Sweet potato leaf tips have high nutritional value,and exploring the differences in the metabolic profiles of leaf tips among different sweet potato varieties can provide information to improve their qualities.In this...Sweet potato leaf tips have high nutritional value,and exploring the differences in the metabolic profiles of leaf tips among different sweet potato varieties can provide information to improve their qualities.In this study,a UPLC-Q-Exactive Orbitrap/MS-based untargeted metabolomics method was used to evaluate the metabolites in leaf tips of 32 sweet potato varieties.Three varieties with distinct overall metabolic profiles(A01,A02,and A03),two varieties with distinct profiles of phenolic acids(A20 and A18),and three varieties with distinct profiles of flavonoids(A05,A12,and A16)were identified.In addition,a total of 163 and 29 differentially expressed metabolites correlated with the color and leaf shape of sweet potato leaf tips,respectively,were identified through morphological characterization.Group comparison analysis of the phenotypic traits and a metabolite-phenotypic trait correlation analysis indicated that the color differences of sweet potato leaf tips were markedly associated with flavonoids.Also,the level of polyphenols was correlated with the leaf shape of sweet potato leaf tips,with lobed leaf types having higher levels of polyphenols than the entire leaf types.The findings on the metabolic profiles and differentially expressed metabolites associated with the morphology of sweet potato leaf tips can provide useful information for breeding sweet potato varieties with higher nutritional value.展开更多
Background: Liver abscess (LA) is a suppurated collection in the hepatic parenchyma. In Africa, liver abscesses are most often of amoebic origin, but more recently, the rate of pyogenic liver abscesses (PLA) has incre...Background: Liver abscess (LA) is a suppurated collection in the hepatic parenchyma. In Africa, liver abscesses are most often of amoebic origin, but more recently, the rate of pyogenic liver abscesses (PLA) has increased. Objective: to assess the epidemiological characteristics, clinical features, biological radiological findings, and outcomes of patients with PLA and with amebic liver abscess (ALA) in order to determine the potential factors that may help improve diagnosis and treatment for LA in the context of secondary care centers with limited medical supports. Methods: Retrospective review of LA diagnosed and treated at three secondary care centers in Thiès over 11 years. Results: 61 patients, were included, 52.45% had ALA and 47.54% had PLA. Males were predominant (79.31% in PLA vs 65.63% in ALA, p = 0.2). The median age was 38 years for the PLA group vs 39 years for the ALA group (p = 0.4). In both groups, the most common symptom was right upper abdominal pain (81.97%), hepatomegaly (81.97%). The PLA group had a higher prevalence of fever (79.31% vs 46.88%, p = 0,009), chills (51.72% vs 18.75%, p = 0.007), right basi-thoracic pain (55.17% vs 28.13%, p = 0.032), and jaundice (55.17% vs 28%, p = 0.032). There was no difference in radiological features between PLA and ALA. Patients with PLA had a higher level of White blood cell (20.600 vs 15.400, p = 0.014). The most common bacteria identified in PLA were Escherichia coli (58.8%). All patients had received antibiotic therapy, which was combined with aspiration puncture (37.3%), transcutaneous drainage (43.3%), and surgery (9.0%). Seven patients had received antibiotic therapy alone and all had amoebic abscesses. Elsewhere, the occurrence of complications was higher in PLA cases (75.86% vs 37.5%, p = 0.003). The overall hospital mortality rate was 13.11%, higher in cases of PLA (24.14% vs 3.13%, p = 0.022). Conclusion: Clinical and biological features were more severe in PLA. But radiological features cannot be used to distinguish between PLA and ALA.展开更多
This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the fe...This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular spacing.In addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any overshoots.The significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient profiles.Furthermore,all variables existing in the entire system are analyzed to be convergent.Simulation and experimental results are provided to validate the utility of suggested solution.展开更多
Background: Cervical cancer (CC) is one of the most frequent cancers and the leading cause of death from gynecological cancer in Low and middle income countries, Cameroon inclusive. Surgery is the primary treatment mo...Background: Cervical cancer (CC) is one of the most frequent cancers and the leading cause of death from gynecological cancer in Low and middle income countries, Cameroon inclusive. Surgery is the primary treatment modality when the disease is diagnosed at early stage. Radical hysterectomy in cervical cancer has not been evaluated in recent years in Cameroon. The purpose of this study is thus to evaluate the epidemiological and clinical features and short term outcomes of patients who underwent surgery. Patients and methods: This retrospective study was conducted at the Douala Gynaeco-obstetric and Pediatric Hospital and the Douala General Hospital. Cervical cancer patients who underwent Radical hysterectomy between January 2015 and December 2020 were included. A pre-established data collection tool was used to record socio-demographic, clinical and outcomes information from patients’ files;additional outcome information was obtained from phone calls. Descriptive analysis was done using the SPSS version 26. Bivariate analysis was used to determine associations between disease and patients characteristics and occurrence of adverse postoperative outcome. P value of 0.05 was considered. Results: Sixty one patients were enrolled. Their ages ranged from 33 to 74 years with a mean age of 51.95 ± 10.29 years. Over 85% of women were married, 65.57% were unemployed and 86.88% were multiparous. Only 28% had never done cervical cancer screening. Most patients had stage IB1 to IB2 stage disease (57.1%). Less than 9% underwent radical hysterectomy and 8 of those (13.11%) suffered intraoperative complications. Twenty-five patients (40.98%) presented immediate and short term complications. There was no significant association between the disease or patients’ characteristics and adverse outcomes. Conclusion: Cervical cancer patients are relatively young in our settings and only 9% of them reach the hospital at early stage. Postoperative adverse outcomes rate is higher than that reported in the literature. Sensitization on screening and awareness of early symptoms can reverse the situation.展开更多
In this work, we investigated aroma volatiles emanated by dry roots, stems, leaves, flowers, and fruits of Cardariadraba (L.) Desv. growing wild in Tunisia and its aerial part essential oils (EOs) composition. A total...In this work, we investigated aroma volatiles emanated by dry roots, stems, leaves, flowers, and fruits of Cardariadraba (L.) Desv. growing wild in Tunisia and its aerial part essential oils (EOs) composition. A total of 37 volatileorganic compounds (96.7%–98.9%) were identified;4 esters, 4 alcohols, 7 hydrocarbons, 12 aldehydes, 5 ketones,1 lactone, 1 organosulfur compound, 2 organonitrogen compounds, and 1 acid. The hydrocarbons form the maingroup, representing 49.5%–84.6% of the total detected volatiles. The main constituent was 2,2,4,6,6-pentamethylheptane(44.5%–76.2%) reaching the highest relative percentages. Forty-two compounds were determined in thetwo fractions of EOs, representing 98.8% and 97.2% of the total oil composition, respectively. The principal componentswere hexadecanoic acid (34.6%), 6-methyl-5-hepten-2-one (18.3%), decanal (15.0%), 6,10,14-trimethyl-2-pentadecanone (13.2%), and n-pentacosane (13%). Micromorphological details of the leaf and stem epidermisusing light microscopy revealed polygonal cells with sinuous walls in the adaxial and abaxial leaf surfaces andnearly rectangular and long ones with linear and thick walls for the stem epidermis. The stomata complexes wereanisocytic in the leaf epidermis and mainly anisocytic and rarely paracytic in the stem epidermis. Non-glandulartrichomes were unbranched and long with an acute apex or short with a convex apex. The glandular ones wereidentified for the first time in this species. They were short-stalked with a large secretory head. The highest stomatalindex (17.02%) was recorded in the abaxial leaf surface. The identification of headspace volatiles and essentialoil compounds can be used to characterize this species, and the various epidermis micromorphologicalfeatures are very useful for biosystematics taxonomic studies within Brassicaceae.展开更多
The effects of the co-inoculation of Debaryomyces hansenii separately with 3 lactic acid bacteria(LAB),Lactobacillus sakei,Lactobacillus plantarum and Lactobacillus curvatus,on the taste and odour profi les of dry sau...The effects of the co-inoculation of Debaryomyces hansenii separately with 3 lactic acid bacteria(LAB),Lactobacillus sakei,Lactobacillus plantarum and Lactobacillus curvatus,on the taste and odour profi les of dry sausages were investigated.The co-inoculated sausages showed higher free amino acid and organic acid contents than the non-inoculated control and sausages inoculated with D.hansenii alone.Meanwhile,the sausages inoculated with D.hansenii+L.plantarum,D.hansenii+L.sakei and D.hansenii+L.curvatus had the highest contents of aldehydes,esters and alcohols,respectively.The results of electronic tongue,electronic nose and sensory evaluation demonstrated that compared with the sausage inoculated with D.hansenii,the sour taste and fl oral odour increased and the fatty odour decreased in the sausage inoculated with D.hansenii+L.sakei;this was more favourable for the development of a desirable fl avour in sausages.Moreover,the partial least squares regression analysis indicated that 10 taste and 33 odour compounds were mainly responsible for the differences in the flavour profiles among the sausages.Overall,these findings contributed to a more comprehensive understanding of the formation of sensory characteristics in dry sausages co-inoculated with yeast and LAB.展开更多
Objective Previous studies on the association between lipid profiles and chronic kidney disease(CKD)have yielded inconsistent results and no defined thresholds for blood lipids.Methods A prospective cohort study inclu...Objective Previous studies on the association between lipid profiles and chronic kidney disease(CKD)have yielded inconsistent results and no defined thresholds for blood lipids.Methods A prospective cohort study including 32,351 subjects who completed baseline and follow-up surveys over 5 years was conducted.Restricted cubic splines and Cox models were used to examine the association between the lipid profiles and CKD.A regression discontinuity design was used to determine the cutoff value of lipid profiles that was significantly associated with increased the risk of CKD.Results Over a median follow-up time of 2.2(0.5,4.2)years,648(2.00%)subjects developed CKD.The lipid profiles that were significantly and linearly related to CKD included total cholesterol(TC),triglycerides(TG),high-density lipoprotein cholesterol(HDL-C),TC/HDL-C,and TG/HDL-C,whereas lowdensity lipoprotein cholesterol(LDL-C)and LDL-C/HDL-C were nonlinearly correlated with CKD.TC,TG,TC/HDL-C,and TG/HDL-C showed an upward jump at the cutoff value,increasing the risk of CKD by 0.90%,1.50%,2.30%,and 1.60%,respectively,whereas HDL-C showed a downward jump at the cutoff value,reducing this risk by 1.0%.Female and participants with dyslipidemia had a higher risk of CKD,while the cutoff values for the different characteristics of the population were different.Conclusion There was a significant association between lipid profiles and CKD in a prospective cohort from Northwest China,while TG,TC/HDL-C,and TG/HDL-C showed a stronger risk association.The specific cutoff values of lipid profiles may provide a clinical reference for screening or diagnosing CKD risk.展开更多
BACKGROUND The coronavirus disease 2019(COVID-19)pandemic has been linked to an increased incidence of diabetes and diabetic ketoacidosis(DKA).However,the relationship between COVID-19 infection and progression to typ...BACKGROUND The coronavirus disease 2019(COVID-19)pandemic has been linked to an increased incidence of diabetes and diabetic ketoacidosis(DKA).However,the relationship between COVID-19 infection and progression to type 1 diabetes(T1D)in children has not been well defined.AIM To evaluate the influence of COVID-19 infection and inactivated vaccine adminis-tration on the progression of T1D among Chinese children.METHODS A total of 197 newly diagnosed patients with T1D were retrospectively enrolled from Children's Hospital of Fudan University between September 2020 and December 2023.The patients were divided into three groups based on their history of COVID-19 infection and vaccination:the infection group,the vacci-nation-only group,and the non-infection/non-vaccination group.Comprehensive clinical assessments and detailed immunological evaluations were performed to delineate the characteristics and immune responses of these groups.RESULTS The incidence of DKA was significantly higher in the COVID-19 infection group(70.2%)compared to the non-infection/non-vaccination group(62.5%)and vac-scination-only group(45.6%;P=0.015).Prior COVID-19 infection was correlated with increased DKA risk(OR:1.981,95%CI:1.026-3.825,P=0.042),while vacci-nation was associated with a reduced risk(OR:0.558,95%CI:0.312-0.998,P=0.049).COVID-19 infection mildly altered immune profiles,with modest dif-ferences in autoantibody positivity,lymphocyte distribution,and immunoglobulin levels.Notably,HLA-DR3 po-sitive children with a history of COVID-19 infection had an earlier T1D onset and lower fasting C-peptide levels than the HLA-DR3 negative children with a history of infection(both P<0.05).CONCLUSION COVID-19 infection predisposes children to severe T1D,characterized by enhanced DKA risk.Inactivated vaccination significantly lowers DKA incidence at T1D onset.These findings are valuable for guiding future vaccination and T1D risk surveillance strategies in epidemic scenarios in the general pediatric population.展开更多
Background:The International Agency for Research on Cancer(IARC)released the latest estimates of the global burden of cancer.We present a comparison of cancer profiles between 2020 and 2022,leveraging data from the Gl...Background:The International Agency for Research on Cancer(IARC)released the latest estimates of the global burden of cancer.We present a comparison of cancer profiles between 2020 and 2022,leveraging data from the Global Cancer Statistics(GLOBOCAN).Methods:Cancer incidence and mortality data were sourced from two different years,2020 and 2022,in the GLOBOCAN database.We tracked changes in age-standardized incidence and mortality rates,as well as estimated numbers of new cancer cases and deaths of the 15 most common cancer types globally and in China between 2020 and 2022.Additionally,we conducted comparisons to assess alterations in the cancer burden and variations in mortality-to-incidence ratio(MIR)across different regions and countries for both 2020 and 2022.Results:Lung cancer remained the most common cancer and the leading cause of cancer death worldwide.The new cases of thyroid cancer witnessed a sharp increase in 2022.Conversely,the numbers of new cancer cases and deaths from stomach and esophageal cancer decreased significantly in 2022.The geographic distribution of cancer incidence and mortality across six continents in 2022 largely mirrored that of 2020.Higher Human Development Index(HDI)levels in countries corresponded with elevated rates of cancer incidence and mortality,consistent with the previous year.Among 185 countries or territories,China’s age-standardized incidence rate(ASIR)ranked 64th and its age-standardized mortality rate(ASMR)ranked 68th,aligning with global averages.Lung cancer continued to impose the greatest burden of incidence and mortality.Stomach,breast,and esophageal cancers showed declines in both case counts and ASIR.Noteworthy reductions in both ASMR and absolute mortality numbers were observed in liver,stomach,and esophageal cancers.The global MIR decreased from 0.516 in 2020 to 0.488 in 2022.MIR trends indicated an upward trajectory with decreasing HDI levels in both 2022 and 2020.While Canada,Germany,India,Italy,Japan,and the United Kingdom demonstrated increasing MIRs,China exhibited the most significant decrease,followed by Russia and the United States.Conclusions:The global landscape of cancer incidence and mortality in 2022 reflects ongoing trends observed in 2020.Cancer burdens vary notably across countries with differing socioeconomic statuses.Decreases in stomach,liver,and esophageal cancer cases and deaths signify progress in cancer control efforts.The decrease in the global MIRs highlights potential improvements in cancer management.展开更多
BACKGROUND Disorders of gut-brain interaction(DGBI)are common,but knowledge about their physiopathology is still poor,nor valid tools have been used to evaluate them in childhood.AIM To develop a psycho-gastroenterolo...BACKGROUND Disorders of gut-brain interaction(DGBI)are common,but knowledge about their physiopathology is still poor,nor valid tools have been used to evaluate them in childhood.AIM To develop a psycho-gastroenterological questionnaire(PGQ)to assess the psycho-gastroenterological profile and social characteristics of a pediatric population with and without DGBI.METHODS One hundred and nineteen Italian children(age 11-18)were included:28 outpatient patients with DGBI(Rome IV criteria)and 91 healthy controls.They filled the PGQ,faces pain scale revised(FPS-R),Bristol stool chart,ga-strointestinal symptoms rating scale,state-trait anxiety inventory,Toronto alexithymia scale 20,perceived self-efficacy in the management of negative emotions and expression of positive emotions(APEN-G,APEP-G),irritable bowel syndrome-quality of life questionnaire,school performances,tobacco use,early life events,degree of digital-ization.RESULTS Compared to controls,patients had more medical examinations(35%of them went to the doctor more than five times),a higher school performance(23%vs 13%,P<0.05),didn’t use tobacco(never vs 16%,P<0.05),had early life events(28%vs 1%P<0.05)and a higher percentage of pain classified as 4 in the FPS-R during the examination(14%vs 7%,P<0.05).CONCLUSION Pediatric outpatients with DGBI had a higher prevalence of early life events,a lower quality of life,more medical examinations rising health care costs,lower anxiety levels.展开更多
Background:The aim of this study was to analyze the bi-directional causal relation-ship between lipid profile and characteristics related to muscle atrophy by using a bi-directional Mendelian randomization(MR)analysis...Background:The aim of this study was to analyze the bi-directional causal relation-ship between lipid profile and characteristics related to muscle atrophy by using a bi-directional Mendelian randomization(MR)analysis.Methods:The appendicular lean mass(ALM),whole body fat-free mass(WBFFM)and trunk fat-free mass(TFFM)were used as genome-wide association study(GWAS)data for evaluating muscle mass;the usual walking pace(UWP)and low grip strength(LGS)were used as GWAS data for evaluating muscle strength;and the triglycerides(TG),total cholesterol(TC),high density lipoprotein cholesterol(HDL),low density lipo-protein cholesterol(LDL),apolipoprotein A-1(Apo A-1),and apolipoprotein B(Apo B)were used as GWAS data for evaluating lipid profile.For specific investigations,we mainly employed inverse variance weighting for causal estimation and MR-Egger for pleiotropy analysis.Results:MR results showed that the lipid profile predicted by genetic variants was negatively correlated with muscle mass,positively correlated with UWP,and was not causally correlated with LGS.On the other hand,the muscle mass predicted by genetic variants was negatively correlated with lipid profile,the UWP predicted by genetic variants was mainly positively correlated with lipid profile,while the LGS pre-dicted by genetic variants had no relevant causal relationship with lipid profile.Conclusions:Findings of this MR analysis suggest that hyperlipidemia may affect muscle mass and lead to muscle atrophy,but has no significant effect on muscle strength.On the other hand,increased muscle mass may reduce the incidence of dyslipidemia.展开更多
The traditional orbit determination method based on pulsar profile distortion can determine the six elements of the orbit.However,the estimation accuracies of these methods are limited and the computational load of a ...The traditional orbit determination method based on pulsar profile distortion can determine the six elements of the orbit.However,the estimation accuracies of these methods are limited and the computational load of a six-dimensional search is huge.To solve this problem,the differential-geometry-based Multi-dimensional Joint Position-Velocity Estimation(MJPVE)using Crab pulsar profile distortion is proposed in this paper.Firstly,through theoretical analysis,it is found that the pulsar profile distortion caused by the initial state error in some joint positionvelocity directions is very small.In other words,the accuracies of estimation in these directions are very low.Namely,the search dimension can be reduced,which in turn greatly reduces the computational load.Then,we construct the chi-squared function of the pulsar profile with respect to the estimation error in joint position-velocity direction and use differential geometry to find the joint position-velocity directions corresponding to different degrees of distortion.Finally,we utilize the grid search based on directory folding in these joint position-velocity directions corresponding to large degrees of distortion to obtain the joint position-velocity estimation.The experimental results show that compared with the grouping bi-chi-squared inversion method,MJPVE has high precision and extensive navigation information.展开更多
The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficien...The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficiency and low-cost manufacturing of the component.Blank design is the key part of plastic forming process design.For spinning-rolling process,the shape and size of the blank play a crucial role in process stability,deformation behavior and dimensional accuracy.So this work proposes a blank design method to determine the geometry structure and sizes of the blank.The mathematical model for calculating the blank size has been deduced based on volume conservation and neutral layer length invariance principle.The FE simulation and corresponding trial production of an actual big-tapered profiled ring disk show that the proposed blank design method is applicative.In order to obtain a preferred blank,the influence rules of blank size determined by different deformation degrees(rolling ratio k)on the spinning-rolling process are revealed by comprehensive FE simulations.Overall considering the process stability,circularity of the deformed ring disk and forming forces,a reasonable range of deformation degree(rolling ratio k)is recommended for the blank design of the new spinning-rolling process.展开更多
CO2 concentrations at different heights in a broadleaved/Korean forest (with a mean height of 26 m) were measured with infrared gas analyzer IRGA (model 2250D, LI-COR Inc. and LI-COR, 820) from Aug. to Oct. of 1999, A...CO2 concentrations at different heights in a broadleaved/Korean forest (with a mean height of 26 m) were measured with infrared gas analyzer IRGA (model 2250D, LI-COR Inc. and LI-COR, 820) from Aug. to Oct. of 1999, Apr. to Jul. of 2000, and from Aug. 2002 to Sept. 2003. Based on the collected dada, the diurnal and seasonal dynamics of profiles and storage of carbon dioxide in the forest were analyzed. The diurnal CO2 profiles showed that the vertical distribution of CO2 concentration were different for daytime and nighttime, and the CO2 concentration was highest close to forest floor, no matter at daytime and nighttime. The seasonal profiles of CO2 showed that stratification in the canopy was evident during growth season. CO2 concentrations at different heights (60 m to 2.5 m) had a little change in March, with a difference of 10 mmolmol-1, but had a significant change in July, with a difference of 60 mmolmol-1. In July, there also existed a greater gradient of CO2 concentrations at canopy (22, 26 and 32 m), with a difference of 8 mmolmol-1. The calculated total storage (ΔC/Δt ) of CO2 in the air column with height of 40 m beneath eddy covariance instrument was negative, and made a little contribution to NEE.展开更多
The gas_well system permanently installed in the soil was adopted for studying the dynamic relationship between CO 2 profiles and seedling root growth of Pinus sylvestris var. sylvestriformis (Takenouchi) Che...The gas_well system permanently installed in the soil was adopted for studying the dynamic relationship between CO 2 profiles and seedling root growth of Pinus sylvestris var. sylvestriformis (Takenouchi) Cheng et C. D. Chu. The study was conducted in the Open Research Station of Changbai Mountain Forest Ecological System, The Chinese Academy of Sciences from 1999 to 2001. Four treatments were arranged in the rectangular open_top chambers (OTCs): ambient CO 2+no_seedling, 700 μmol/mol CO 2+no_seedling, ambient CO 2 +seedlings, 700 μmol/mol CO 2+seedlings. By collecting and analyzing soil gas synchronously, it was found that the dynamics of CO 2 profiles were related to the biological activity of seedlings. There were more roots distributed in the top soil and the boundary layer across soil and sand, which made more contributions to the CO 2 profiles due to respiration root. Compared with the ambient CO 2, elevated CO 2 led to the peak of CO 2 concentration distribution shifted from soil surface layer to the boundary layer as seasonally growing of seedling roots. It is suggested the gas_well system is an inexpensive, non_destructive and relatively sensitive method for study of soil CO 2 concentration profiles.展开更多
Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain ...Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters (PMzs) from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon (EC) and organic carbon (OC) was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum (GC-MS). Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. 13-Sitostrol also made up relatively a large fraction of PMz5 compared with the other sterols (0.18%-0.63% of the total fine particle mass). Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index (CPI) of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches.展开更多
Organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflow...Organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflowing river (Fuhe River) in North China. Total concentrations of OCPs, PCBs and PAHs in sediments ranged from 5.4 to 707.6 ng]g, 2.3 to 197.8 ng/g, and 101.3 to 6360.5 ng]g, respectively. The levels of contaminants in Fuhe River were significantly higher than those in Baiyandian Lake. For hexachlorocyclohexane (HCHs) and dichlorodiphenytrich/oroethanes (DDTs), α-HCH and p,p'-DDT were predominant isomers; while for PCBs, PCB 28/31, PCB 40/103, PCB 60, PCB 101, and PCB 118 were predominant congeners. Possible sources derived from historical usage for OCPs and incomplete combustion fuel, wood, and coal and exhaustion of boats or cars for PAHs. Risk assessment of sediment indicated that sediments in Fuhe River were likely to pose potential biological adverse impact.展开更多
Back propagation neural networks are used to retrieve atmospheric temperature profiles from NOAA-16 Advanced Microwave Sounding Unit-A (AMSU-A) measurements over East Asia. The collocated radiosonde observation and AM...Back propagation neural networks are used to retrieve atmospheric temperature profiles from NOAA-16 Advanced Microwave Sounding Unit-A (AMSU-A) measurements over East Asia. The collocated radiosonde observation and AMSU-A data over land in 2002-2003 are used to train the network, and the data over land in 2004 are used to test the network. A comparison with the multi-linear regression method shows that the neural network retrieval method can significantly improve the results in all weather conditions. When an offset of 0.5 K or a noise level of ±0.2 K is added to all channels simultaneously, the increase in the overall root mean square (RMS) error is less than 0.1 K. Furthermore, an experiment is conducted to investigate the effects of the window channels on the retrieval. The results indicate that the brightness temperatures of window channels can provide significantly useful information on the temperature retrieval near the surface. Additionally, the RMS errors of the profiles retrieved with the trained neural network are compared with the errors from the International Advanced TOVS (ATOVS) Processing Package (IAPP). It is shown that the network-based algorithm can provide much better results in the experiment region and comparable results in other regions. It is also noted that the network can yield remarkably better results than IAPP at the low levels and at about the 250-hPa level in summer skies over ocean. Finally, the network-based retrieval algorithm developed herein is applied in retrieving the temperature anomalies of Typhoon Rananim from AMSU-A data.展开更多
Objective To calculate the effects of malnutrition on economic productivity in China. Methods PROFILES was used to quantify the function consequences of malnutrition in term of protein energy malnutrition, iron defici...Objective To calculate the effects of malnutrition on economic productivity in China. Methods PROFILES was used to quantify the function consequences of malnutrition in term of protein energy malnutrition, iron deficiency and iodine deficiency. Results Productivity gained due to improved iodine nutrition. The reduction in the TGR in 1992 to 2001 increased the net present value of further economic productivity by $142 billion. Reduction of the TGR rate to 5% over next 10 years would result in future productivity gains with value of $40 billion. Productivity gain due to reductions in child stunting would result in future economic productivity gains with the value of $101 billion. Reducing stunting further over the next 10 years would gain $20 billion. Productivity gain due to reduction of iron deficiency anemia reduced by 30% over the next 10 years would gain worth $107 billion and if childhood anemia reduced by 30% over next 10 years would gain $348 billion. Conclusion These interventions have huge economic payoff. That is likely to exceed their costs many times over.展开更多
基金This work was supported by grants from the construction and operation of the Food Nutrition and Health Research Center of Guangdong Academy of Agricultural Sciences,China(XTXM 202205)the earmarked fund for CARS-10Sweetpotato,and the Guangdong Modern Agro-industry Technology Research System,China(2022KJ111).
文摘Sweet potato leaf tips have high nutritional value,and exploring the differences in the metabolic profiles of leaf tips among different sweet potato varieties can provide information to improve their qualities.In this study,a UPLC-Q-Exactive Orbitrap/MS-based untargeted metabolomics method was used to evaluate the metabolites in leaf tips of 32 sweet potato varieties.Three varieties with distinct overall metabolic profiles(A01,A02,and A03),two varieties with distinct profiles of phenolic acids(A20 and A18),and three varieties with distinct profiles of flavonoids(A05,A12,and A16)were identified.In addition,a total of 163 and 29 differentially expressed metabolites correlated with the color and leaf shape of sweet potato leaf tips,respectively,were identified through morphological characterization.Group comparison analysis of the phenotypic traits and a metabolite-phenotypic trait correlation analysis indicated that the color differences of sweet potato leaf tips were markedly associated with flavonoids.Also,the level of polyphenols was correlated with the leaf shape of sweet potato leaf tips,with lobed leaf types having higher levels of polyphenols than the entire leaf types.The findings on the metabolic profiles and differentially expressed metabolites associated with the morphology of sweet potato leaf tips can provide useful information for breeding sweet potato varieties with higher nutritional value.
文摘Background: Liver abscess (LA) is a suppurated collection in the hepatic parenchyma. In Africa, liver abscesses are most often of amoebic origin, but more recently, the rate of pyogenic liver abscesses (PLA) has increased. Objective: to assess the epidemiological characteristics, clinical features, biological radiological findings, and outcomes of patients with PLA and with amebic liver abscess (ALA) in order to determine the potential factors that may help improve diagnosis and treatment for LA in the context of secondary care centers with limited medical supports. Methods: Retrospective review of LA diagnosed and treated at three secondary care centers in Thiès over 11 years. Results: 61 patients, were included, 52.45% had ALA and 47.54% had PLA. Males were predominant (79.31% in PLA vs 65.63% in ALA, p = 0.2). The median age was 38 years for the PLA group vs 39 years for the ALA group (p = 0.4). In both groups, the most common symptom was right upper abdominal pain (81.97%), hepatomegaly (81.97%). The PLA group had a higher prevalence of fever (79.31% vs 46.88%, p = 0,009), chills (51.72% vs 18.75%, p = 0.007), right basi-thoracic pain (55.17% vs 28.13%, p = 0.032), and jaundice (55.17% vs 28%, p = 0.032). There was no difference in radiological features between PLA and ALA. Patients with PLA had a higher level of White blood cell (20.600 vs 15.400, p = 0.014). The most common bacteria identified in PLA were Escherichia coli (58.8%). All patients had received antibiotic therapy, which was combined with aspiration puncture (37.3%), transcutaneous drainage (43.3%), and surgery (9.0%). Seven patients had received antibiotic therapy alone and all had amoebic abscesses. Elsewhere, the occurrence of complications was higher in PLA cases (75.86% vs 37.5%, p = 0.003). The overall hospital mortality rate was 13.11%, higher in cases of PLA (24.14% vs 3.13%, p = 0.022). Conclusion: Clinical and biological features were more severe in PLA. But radiological features cannot be used to distinguish between PLA and ALA.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.62173312 and 61803348in part by the National Major Scientific Instruments Development Project under Grant No.61927807+3 种基金in part by the Program for the Innovative Talents of Higher Education Institutions of ShanxiShanxi Province Science Foundation for Excellent Youthsin part by the Shanxi"1331 Project"Key Subjects Construction(1331KSC)in part by Graduate Innovation Project of Shanxi Province under Grant No.2021Y617。
文摘This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular spacing.In addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any overshoots.The significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient profiles.Furthermore,all variables existing in the entire system are analyzed to be convergent.Simulation and experimental results are provided to validate the utility of suggested solution.
文摘Background: Cervical cancer (CC) is one of the most frequent cancers and the leading cause of death from gynecological cancer in Low and middle income countries, Cameroon inclusive. Surgery is the primary treatment modality when the disease is diagnosed at early stage. Radical hysterectomy in cervical cancer has not been evaluated in recent years in Cameroon. The purpose of this study is thus to evaluate the epidemiological and clinical features and short term outcomes of patients who underwent surgery. Patients and methods: This retrospective study was conducted at the Douala Gynaeco-obstetric and Pediatric Hospital and the Douala General Hospital. Cervical cancer patients who underwent Radical hysterectomy between January 2015 and December 2020 were included. A pre-established data collection tool was used to record socio-demographic, clinical and outcomes information from patients’ files;additional outcome information was obtained from phone calls. Descriptive analysis was done using the SPSS version 26. Bivariate analysis was used to determine associations between disease and patients characteristics and occurrence of adverse postoperative outcome. P value of 0.05 was considered. Results: Sixty one patients were enrolled. Their ages ranged from 33 to 74 years with a mean age of 51.95 ± 10.29 years. Over 85% of women were married, 65.57% were unemployed and 86.88% were multiparous. Only 28% had never done cervical cancer screening. Most patients had stage IB1 to IB2 stage disease (57.1%). Less than 9% underwent radical hysterectomy and 8 of those (13.11%) suffered intraoperative complications. Twenty-five patients (40.98%) presented immediate and short term complications. There was no significant association between the disease or patients’ characteristics and adverse outcomes. Conclusion: Cervical cancer patients are relatively young in our settings and only 9% of them reach the hospital at early stage. Postoperative adverse outcomes rate is higher than that reported in the literature. Sensitization on screening and awareness of early symptoms can reverse the situation.
文摘In this work, we investigated aroma volatiles emanated by dry roots, stems, leaves, flowers, and fruits of Cardariadraba (L.) Desv. growing wild in Tunisia and its aerial part essential oils (EOs) composition. A total of 37 volatileorganic compounds (96.7%–98.9%) were identified;4 esters, 4 alcohols, 7 hydrocarbons, 12 aldehydes, 5 ketones,1 lactone, 1 organosulfur compound, 2 organonitrogen compounds, and 1 acid. The hydrocarbons form the maingroup, representing 49.5%–84.6% of the total detected volatiles. The main constituent was 2,2,4,6,6-pentamethylheptane(44.5%–76.2%) reaching the highest relative percentages. Forty-two compounds were determined in thetwo fractions of EOs, representing 98.8% and 97.2% of the total oil composition, respectively. The principal componentswere hexadecanoic acid (34.6%), 6-methyl-5-hepten-2-one (18.3%), decanal (15.0%), 6,10,14-trimethyl-2-pentadecanone (13.2%), and n-pentacosane (13%). Micromorphological details of the leaf and stem epidermisusing light microscopy revealed polygonal cells with sinuous walls in the adaxial and abaxial leaf surfaces andnearly rectangular and long ones with linear and thick walls for the stem epidermis. The stomata complexes wereanisocytic in the leaf epidermis and mainly anisocytic and rarely paracytic in the stem epidermis. Non-glandulartrichomes were unbranched and long with an acute apex or short with a convex apex. The glandular ones wereidentified for the first time in this species. They were short-stalked with a large secretory head. The highest stomatalindex (17.02%) was recorded in the abaxial leaf surface. The identification of headspace volatiles and essentialoil compounds can be used to characterize this species, and the various epidermis micromorphologicalfeatures are very useful for biosystematics taxonomic studies within Brassicaceae.
基金funded by the National Natural Science Foundation of China(32172232 and 31771990)the Major Science and Technology Projects of Heilongjiang Province(2021ZX12B05).
文摘The effects of the co-inoculation of Debaryomyces hansenii separately with 3 lactic acid bacteria(LAB),Lactobacillus sakei,Lactobacillus plantarum and Lactobacillus curvatus,on the taste and odour profi les of dry sausages were investigated.The co-inoculated sausages showed higher free amino acid and organic acid contents than the non-inoculated control and sausages inoculated with D.hansenii alone.Meanwhile,the sausages inoculated with D.hansenii+L.plantarum,D.hansenii+L.sakei and D.hansenii+L.curvatus had the highest contents of aldehydes,esters and alcohols,respectively.The results of electronic tongue,electronic nose and sensory evaluation demonstrated that compared with the sausage inoculated with D.hansenii,the sour taste and fl oral odour increased and the fatty odour decreased in the sausage inoculated with D.hansenii+L.sakei;this was more favourable for the development of a desirable fl avour in sausages.Moreover,the partial least squares regression analysis indicated that 10 taste and 33 odour compounds were mainly responsible for the differences in the flavour profiles among the sausages.Overall,these findings contributed to a more comprehensive understanding of the formation of sensory characteristics in dry sausages co-inoculated with yeast and LAB.
基金supported by the Municipal Science and Technology Program of Wuwei City,China(WW2202RPZ037)the Fundamental Research Funds for the Central Universities in China(Grant No.lzujbky-2018-69).
文摘Objective Previous studies on the association between lipid profiles and chronic kidney disease(CKD)have yielded inconsistent results and no defined thresholds for blood lipids.Methods A prospective cohort study including 32,351 subjects who completed baseline and follow-up surveys over 5 years was conducted.Restricted cubic splines and Cox models were used to examine the association between the lipid profiles and CKD.A regression discontinuity design was used to determine the cutoff value of lipid profiles that was significantly associated with increased the risk of CKD.Results Over a median follow-up time of 2.2(0.5,4.2)years,648(2.00%)subjects developed CKD.The lipid profiles that were significantly and linearly related to CKD included total cholesterol(TC),triglycerides(TG),high-density lipoprotein cholesterol(HDL-C),TC/HDL-C,and TG/HDL-C,whereas lowdensity lipoprotein cholesterol(LDL-C)and LDL-C/HDL-C were nonlinearly correlated with CKD.TC,TG,TC/HDL-C,and TG/HDL-C showed an upward jump at the cutoff value,increasing the risk of CKD by 0.90%,1.50%,2.30%,and 1.60%,respectively,whereas HDL-C showed a downward jump at the cutoff value,reducing this risk by 1.0%.Female and participants with dyslipidemia had a higher risk of CKD,while the cutoff values for the different characteristics of the population were different.Conclusion There was a significant association between lipid profiles and CKD in a prospective cohort from Northwest China,while TG,TC/HDL-C,and TG/HDL-C showed a stronger risk association.The specific cutoff values of lipid profiles may provide a clinical reference for screening or diagnosing CKD risk.
基金Supported by National Key Research and Development Program of China,No.2021YFC2701900 and No.2016YFC1305300.
文摘BACKGROUND The coronavirus disease 2019(COVID-19)pandemic has been linked to an increased incidence of diabetes and diabetic ketoacidosis(DKA).However,the relationship between COVID-19 infection and progression to type 1 diabetes(T1D)in children has not been well defined.AIM To evaluate the influence of COVID-19 infection and inactivated vaccine adminis-tration on the progression of T1D among Chinese children.METHODS A total of 197 newly diagnosed patients with T1D were retrospectively enrolled from Children's Hospital of Fudan University between September 2020 and December 2023.The patients were divided into three groups based on their history of COVID-19 infection and vaccination:the infection group,the vacci-nation-only group,and the non-infection/non-vaccination group.Comprehensive clinical assessments and detailed immunological evaluations were performed to delineate the characteristics and immune responses of these groups.RESULTS The incidence of DKA was significantly higher in the COVID-19 infection group(70.2%)compared to the non-infection/non-vaccination group(62.5%)and vac-scination-only group(45.6%;P=0.015).Prior COVID-19 infection was correlated with increased DKA risk(OR:1.981,95%CI:1.026-3.825,P=0.042),while vacci-nation was associated with a reduced risk(OR:0.558,95%CI:0.312-0.998,P=0.049).COVID-19 infection mildly altered immune profiles,with modest dif-ferences in autoantibody positivity,lymphocyte distribution,and immunoglobulin levels.Notably,HLA-DR3 po-sitive children with a history of COVID-19 infection had an earlier T1D onset and lower fasting C-peptide levels than the HLA-DR3 negative children with a history of infection(both P<0.05).CONCLUSION COVID-19 infection predisposes children to severe T1D,characterized by enhanced DKA risk.Inactivated vaccination significantly lowers DKA incidence at T1D onset.These findings are valuable for guiding future vaccination and T1D risk surveillance strategies in epidemic scenarios in the general pediatric population.
文摘Background:The International Agency for Research on Cancer(IARC)released the latest estimates of the global burden of cancer.We present a comparison of cancer profiles between 2020 and 2022,leveraging data from the Global Cancer Statistics(GLOBOCAN).Methods:Cancer incidence and mortality data were sourced from two different years,2020 and 2022,in the GLOBOCAN database.We tracked changes in age-standardized incidence and mortality rates,as well as estimated numbers of new cancer cases and deaths of the 15 most common cancer types globally and in China between 2020 and 2022.Additionally,we conducted comparisons to assess alterations in the cancer burden and variations in mortality-to-incidence ratio(MIR)across different regions and countries for both 2020 and 2022.Results:Lung cancer remained the most common cancer and the leading cause of cancer death worldwide.The new cases of thyroid cancer witnessed a sharp increase in 2022.Conversely,the numbers of new cancer cases and deaths from stomach and esophageal cancer decreased significantly in 2022.The geographic distribution of cancer incidence and mortality across six continents in 2022 largely mirrored that of 2020.Higher Human Development Index(HDI)levels in countries corresponded with elevated rates of cancer incidence and mortality,consistent with the previous year.Among 185 countries or territories,China’s age-standardized incidence rate(ASIR)ranked 64th and its age-standardized mortality rate(ASMR)ranked 68th,aligning with global averages.Lung cancer continued to impose the greatest burden of incidence and mortality.Stomach,breast,and esophageal cancers showed declines in both case counts and ASIR.Noteworthy reductions in both ASMR and absolute mortality numbers were observed in liver,stomach,and esophageal cancers.The global MIR decreased from 0.516 in 2020 to 0.488 in 2022.MIR trends indicated an upward trajectory with decreasing HDI levels in both 2022 and 2020.While Canada,Germany,India,Italy,Japan,and the United Kingdom demonstrated increasing MIRs,China exhibited the most significant decrease,followed by Russia and the United States.Conclusions:The global landscape of cancer incidence and mortality in 2022 reflects ongoing trends observed in 2020.Cancer burdens vary notably across countries with differing socioeconomic statuses.Decreases in stomach,liver,and esophageal cancer cases and deaths signify progress in cancer control efforts.The decrease in the global MIRs highlights potential improvements in cancer management.
文摘BACKGROUND Disorders of gut-brain interaction(DGBI)are common,but knowledge about their physiopathology is still poor,nor valid tools have been used to evaluate them in childhood.AIM To develop a psycho-gastroenterological questionnaire(PGQ)to assess the psycho-gastroenterological profile and social characteristics of a pediatric population with and without DGBI.METHODS One hundred and nineteen Italian children(age 11-18)were included:28 outpatient patients with DGBI(Rome IV criteria)and 91 healthy controls.They filled the PGQ,faces pain scale revised(FPS-R),Bristol stool chart,ga-strointestinal symptoms rating scale,state-trait anxiety inventory,Toronto alexithymia scale 20,perceived self-efficacy in the management of negative emotions and expression of positive emotions(APEN-G,APEP-G),irritable bowel syndrome-quality of life questionnaire,school performances,tobacco use,early life events,degree of digital-ization.RESULTS Compared to controls,patients had more medical examinations(35%of them went to the doctor more than five times),a higher school performance(23%vs 13%,P<0.05),didn’t use tobacco(never vs 16%,P<0.05),had early life events(28%vs 1%P<0.05)and a higher percentage of pain classified as 4 in the FPS-R during the examination(14%vs 7%,P<0.05).CONCLUSION Pediatric outpatients with DGBI had a higher prevalence of early life events,a lower quality of life,more medical examinations rising health care costs,lower anxiety levels.
基金Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2021A1515220030Hunan Provincial Clinical Medical Technology Innovation Guiding Project,Grant/Award Number:2020SK53307+2 种基金Hunan Provincial Health Commission,Grant/Award Number:20201902Natural Science Foundation of Hunan Province,Grant/Award Number:2020JJ8043Project of Hunan Provincial Health,Grant/Award Number:c2019133。
文摘Background:The aim of this study was to analyze the bi-directional causal relation-ship between lipid profile and characteristics related to muscle atrophy by using a bi-directional Mendelian randomization(MR)analysis.Methods:The appendicular lean mass(ALM),whole body fat-free mass(WBFFM)and trunk fat-free mass(TFFM)were used as genome-wide association study(GWAS)data for evaluating muscle mass;the usual walking pace(UWP)and low grip strength(LGS)were used as GWAS data for evaluating muscle strength;and the triglycerides(TG),total cholesterol(TC),high density lipoprotein cholesterol(HDL),low density lipo-protein cholesterol(LDL),apolipoprotein A-1(Apo A-1),and apolipoprotein B(Apo B)were used as GWAS data for evaluating lipid profile.For specific investigations,we mainly employed inverse variance weighting for causal estimation and MR-Egger for pleiotropy analysis.Results:MR results showed that the lipid profile predicted by genetic variants was negatively correlated with muscle mass,positively correlated with UWP,and was not causally correlated with LGS.On the other hand,the muscle mass predicted by genetic variants was negatively correlated with lipid profile,the UWP predicted by genetic variants was mainly positively correlated with lipid profile,while the LGS pre-dicted by genetic variants had no relevant causal relationship with lipid profile.Conclusions:Findings of this MR analysis suggest that hyperlipidemia may affect muscle mass and lead to muscle atrophy,but has no significant effect on muscle strength.On the other hand,increased muscle mass may reduce the incidence of dyslipidemia.
基金supported in part by the National Natural Science Foundation of China(Nos.61873196,62373030,61772187)the Innovation Program for Quantum Science and Technology(No.2021ZD0303400)。
文摘The traditional orbit determination method based on pulsar profile distortion can determine the six elements of the orbit.However,the estimation accuracies of these methods are limited and the computational load of a six-dimensional search is huge.To solve this problem,the differential-geometry-based Multi-dimensional Joint Position-Velocity Estimation(MJPVE)using Crab pulsar profile distortion is proposed in this paper.Firstly,through theoretical analysis,it is found that the pulsar profile distortion caused by the initial state error in some joint positionvelocity directions is very small.In other words,the accuracies of estimation in these directions are very low.Namely,the search dimension can be reduced,which in turn greatly reduces the computational load.Then,we construct the chi-squared function of the pulsar profile with respect to the estimation error in joint position-velocity direction and use differential geometry to find the joint position-velocity directions corresponding to different degrees of distortion.Finally,we utilize the grid search based on directory folding in these joint position-velocity directions corresponding to large degrees of distortion to obtain the joint position-velocity estimation.The experimental results show that compared with the grouping bi-chi-squared inversion method,MJPVE has high precision and extensive navigation information.
基金the National Natural Science Foundation of China(No.52275378)the National Key Laboratory for Precision Hot Processing of Metals(6142909200208)。
文摘The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficiency and low-cost manufacturing of the component.Blank design is the key part of plastic forming process design.For spinning-rolling process,the shape and size of the blank play a crucial role in process stability,deformation behavior and dimensional accuracy.So this work proposes a blank design method to determine the geometry structure and sizes of the blank.The mathematical model for calculating the blank size has been deduced based on volume conservation and neutral layer length invariance principle.The FE simulation and corresponding trial production of an actual big-tapered profiled ring disk show that the proposed blank design method is applicative.In order to obtain a preferred blank,the influence rules of blank size determined by different deformation degrees(rolling ratio k)on the spinning-rolling process are revealed by comprehensive FE simulations.Overall considering the process stability,circularity of the deformed ring disk and forming forces,a reasonable range of deformation degree(rolling ratio k)is recommended for the blank design of the new spinning-rolling process.
基金This study is supported by The Development Plan of State Key Fundamental Research of China (973) (contract No. 2002CB412502),by Knowledge Innovation Project of CAS (KZCX1-SW-01-03) and by Natural Science Foundation of China (30170167).
文摘CO2 concentrations at different heights in a broadleaved/Korean forest (with a mean height of 26 m) were measured with infrared gas analyzer IRGA (model 2250D, LI-COR Inc. and LI-COR, 820) from Aug. to Oct. of 1999, Apr. to Jul. of 2000, and from Aug. 2002 to Sept. 2003. Based on the collected dada, the diurnal and seasonal dynamics of profiles and storage of carbon dioxide in the forest were analyzed. The diurnal CO2 profiles showed that the vertical distribution of CO2 concentration were different for daytime and nighttime, and the CO2 concentration was highest close to forest floor, no matter at daytime and nighttime. The seasonal profiles of CO2 showed that stratification in the canopy was evident during growth season. CO2 concentrations at different heights (60 m to 2.5 m) had a little change in March, with a difference of 10 mmolmol-1, but had a significant change in July, with a difference of 60 mmolmol-1. In July, there also existed a greater gradient of CO2 concentrations at canopy (22, 26 and 32 m), with a difference of 8 mmolmol-1. The calculated total storage (ΔC/Δt ) of CO2 in the air column with height of 40 m beneath eddy covariance instrument was negative, and made a little contribution to NEE.
文摘The gas_well system permanently installed in the soil was adopted for studying the dynamic relationship between CO 2 profiles and seedling root growth of Pinus sylvestris var. sylvestriformis (Takenouchi) Cheng et C. D. Chu. The study was conducted in the Open Research Station of Changbai Mountain Forest Ecological System, The Chinese Academy of Sciences from 1999 to 2001. Four treatments were arranged in the rectangular open_top chambers (OTCs): ambient CO 2+no_seedling, 700 μmol/mol CO 2+no_seedling, ambient CO 2 +seedlings, 700 μmol/mol CO 2+seedlings. By collecting and analyzing soil gas synchronously, it was found that the dynamics of CO 2 profiles were related to the biological activity of seedlings. There were more roots distributed in the top soil and the boundary layer across soil and sand, which made more contributions to the CO 2 profiles due to respiration root. Compared with the ambient CO 2, elevated CO 2 led to the peak of CO 2 concentration distribution shifted from soil surface layer to the boundary layer as seasonally growing of seedling roots. It is suggested the gas_well system is an inexpensive, non_destructive and relatively sensitive method for study of soil CO 2 concentration profiles.
基金Project supported by the Hi-Tech Research and Development Program (863) of China (No. 2001AA641060 2003AA641040)the National Basic Research Program (973) of China (No. 2002CB410801).
文摘Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters (PMzs) from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon (EC) and organic carbon (OC) was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum (GC-MS). Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. 13-Sitostrol also made up relatively a large fraction of PMz5 compared with the other sterols (0.18%-0.63% of the total fine particle mass). Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index (CPI) of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches.
基金supported by the National Basic Research Program (973) of China (No.2006CB403306)the National Natural Science Foundation of China (No.30870311)
文摘Organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflowing river (Fuhe River) in North China. Total concentrations of OCPs, PCBs and PAHs in sediments ranged from 5.4 to 707.6 ng]g, 2.3 to 197.8 ng/g, and 101.3 to 6360.5 ng]g, respectively. The levels of contaminants in Fuhe River were significantly higher than those in Baiyandian Lake. For hexachlorocyclohexane (HCHs) and dichlorodiphenytrich/oroethanes (DDTs), α-HCH and p,p'-DDT were predominant isomers; while for PCBs, PCB 28/31, PCB 40/103, PCB 60, PCB 101, and PCB 118 were predominant congeners. Possible sources derived from historical usage for OCPs and incomplete combustion fuel, wood, and coal and exhaustion of boats or cars for PAHs. Risk assessment of sediment indicated that sediments in Fuhe River were likely to pose potential biological adverse impact.
文摘Back propagation neural networks are used to retrieve atmospheric temperature profiles from NOAA-16 Advanced Microwave Sounding Unit-A (AMSU-A) measurements over East Asia. The collocated radiosonde observation and AMSU-A data over land in 2002-2003 are used to train the network, and the data over land in 2004 are used to test the network. A comparison with the multi-linear regression method shows that the neural network retrieval method can significantly improve the results in all weather conditions. When an offset of 0.5 K or a noise level of ±0.2 K is added to all channels simultaneously, the increase in the overall root mean square (RMS) error is less than 0.1 K. Furthermore, an experiment is conducted to investigate the effects of the window channels on the retrieval. The results indicate that the brightness temperatures of window channels can provide significantly useful information on the temperature retrieval near the surface. Additionally, the RMS errors of the profiles retrieved with the trained neural network are compared with the errors from the International Advanced TOVS (ATOVS) Processing Package (IAPP). It is shown that the network-based algorithm can provide much better results in the experiment region and comparable results in other regions. It is also noted that the network can yield remarkably better results than IAPP at the low levels and at about the 250-hPa level in summer skies over ocean. Finally, the network-based retrieval algorithm developed herein is applied in retrieving the temperature anomalies of Typhoon Rananim from AMSU-A data.
基金This study was funded by The Western Pacific Regional Office of the World Health Organization.
文摘Objective To calculate the effects of malnutrition on economic productivity in China. Methods PROFILES was used to quantify the function consequences of malnutrition in term of protein energy malnutrition, iron deficiency and iodine deficiency. Results Productivity gained due to improved iodine nutrition. The reduction in the TGR in 1992 to 2001 increased the net present value of further economic productivity by $142 billion. Reduction of the TGR rate to 5% over next 10 years would result in future productivity gains with value of $40 billion. Productivity gain due to reductions in child stunting would result in future economic productivity gains with the value of $101 billion. Reducing stunting further over the next 10 years would gain $20 billion. Productivity gain due to reduction of iron deficiency anemia reduced by 30% over the next 10 years would gain worth $107 billion and if childhood anemia reduced by 30% over next 10 years would gain $348 billion. Conclusion These interventions have huge economic payoff. That is likely to exceed their costs many times over.