Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.However,efficient and economic...Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.However,efficient and economic H_(2) production by alkaline water electrolysis is hindered by the sluggish hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Therefore,it is imperative to design and fabricate high-active and low-cost non-precious metal catalysts to improve the HER and OER performance,which affects the energy efficiency of alkaline water electrolysis.Ni_(3)S_(2) with the heazlewoodite structure is a potential electrocatalyst with near-metal conductivity due to the Ni–Ni metal network.Here,the review comprehensively presents the recent progress of Ni_(3)S_(2)-based electrocatalysts for alkaline water electrocatalysis.Herein,the HER and OER mechanisms,performance evaluation criteria,preparation methods,and strategies for performance improvement of Ni_(3)S_(2)-based electrocatalysts are discussed.The challenges and perspectives are also analyzed.展开更多
Objective:To investigate the situation of anaplasmosis in Yiyuan county.Shandong Province. Methods:A total of 26 blood samples from febrile patients suspected of anaplasmosis,48 blood samples from healthy farmers,8 fr...Objective:To investigate the situation of anaplasmosis in Yiyuan county.Shandong Province. Methods:A total of 26 blood samples from febrile patients suspected of anaplasmosis,48 blood samples from healthy farmers,8 from dogs,and 10 from goats and 170 ticks were collected in the same area during 2005-2007,and detected by serological and molecular methods.Results: Eight confirmed cases and 6 probable cases were determined using serologic and molecular methods.The seroprevalence of Anaplasma phagocytophilum(A.phagocytophilum) was 26.7% in healthy cases.Nine out of 10 sheep samples and 7 out of 8 dog samples reacted positively to the A.phagocytophilum antigen.PCR amplification and sequencing of the 16SrRNA of,4. phagocytophilum gene showed that some samples from patients,goats and ticks were 100% identical.The seroprevalence of Rickettsia typhi was 22.9%,Orientia tsutsugamushi 6.3%, Rickettsia sibirica 27.1%,Coxiella burnetii 18.8%,Bartonella henselae 31.3%,and Borrelia burgdorferi 41.6%.Conclusions:It is important to make differential diagnosis of febrile patients and to apply treatment with specific antibiotics.It is needed to enforce essential prevention and control measures including tick control and to improve sanitation conditions.展开更多
Objective:To evaluate the Anaplasma phagocytophilum(A.phagocytophilum),Ehrlichia canis(E.canis,Dirofilaria immitis(D.immitis)(canine heartworm),Borrelia burgdorferi(B.burgdorferi)infections in countryside dogs from Yu...Objective:To evaluate the Anaplasma phagocytophilum(A.phagocytophilum),Ehrlichia canis(E.canis,Dirofilaria immitis(D.immitis)(canine heartworm),Borrelia burgdorferi(B.burgdorferi)infections in countryside dogs from Yunnan,Hainan and Anhui provinces.Methods:Serum samples were collected from 26 dogs in Yunnan.Hainan and Anhui provinces.The samples were tested using a commercial ELISA rapid diagnostic assay kit(SNAP^(?)4Dx^(?);IDEXX Laboratories,Inc.U.S.A.).Meaiiwliile,indirect immunofluorescence assay(IFA)recommended by WHO was conducted to delect IgG to A.phagocytophilum.Two methods were analyzed and compared.Results:The number of serologically positive dogs for IgG to A.phagocytophilum was only 2which was from Hainan province and none of the 26 dogs responded positive for E.canu.D.immitis(canine heartworm,and B.burgdorferi by ELISA rapid diagnostic method.The number of serologically positive dogs for IgG to A.phagocytophilum was 13(50%)by IFA method.Data of the two methods were analyzed by statistical software and the difference was statistically significant(P=0.002).Conclusions:It can be concluded that IFA method was more sensitive than ELISA rapid diagnostic method.However,we need conduct further and intensive epidemiology survey on tick-born diseases pathogens including.4.phagocytophilum,E.canis,D.immitis(canine heartworm),and B.burgdorferi which have public health significance.展开更多
Erratic rainfall and misalignment between the rainy season and the growing season of winter wheat greatly limit rainfed winter wheat yield in the Loess Plateau of China. To increase the grain yield of winter wheat in ...Erratic rainfall and misalignment between the rainy season and the growing season of winter wheat greatly limit rainfed winter wheat yield in the Loess Plateau of China. To increase the grain yield of winter wheat in this region, the effects of different agronomic practices, including adjusting planting pattern(NR, narrow row spacing), increasing seeding rate(high seeding rate, HS), decreasing basal nitrogen rate and increasing top-dressed nitrogen rate(DBN), and replacing an old cultivar with a new cultivar(NC) on wheat yield were investigated for two consecutive years. The results showed that the current grain yield of rainfed winter wheat in the Loess Plateau could be increased to 5879–7093 kg ha^(-1) by HS, DBN and NC practices relative to the practice of high-yielding farmers(PF). The increased yield due to HS, DBN and NC was attributed to the higher number of spikes ha^(-1), 1000-grain weight, and kernels spike^(-1). Before the flowering stage, HS increased soil water consumption(SWC) in 1–3 m subsoil due to the higher plant population compared with that of PF, whereas DBN decreased SWC in the 0–2 m soil layer compared with that of PF. After the flowering stage, HS, DBN, and NC increased SWC by 8–16 mm in 2–3 m subsoil compared to PF. The water use efficiency(WUE) was increased under DBN and NC in comparison with PF.However, the WUE did not increase under HS as it had the highest evapotranspiration among the five treatments. Increasing the use of subsoil water during the late growth stage by optimizing agronomic practices or applying new cultivars with expansive roots should be the primary approach to increase rainfed winter wheat yield in this region.展开更多
Objective To evaluate the feasibility and efficacy of intravascular optical coherence tomography(OCT)in the assessment of plaque characteristics and drug eluting stent deployment quality in the elderly patients with u...Objective To evaluate the feasibility and efficacy of intravascular optical coherence tomography(OCT)in the assessment of plaque characteristics and drug eluting stent deployment quality in the elderly patients with unstable angina(UA)and non-ST segment elevation myocardial infarction(NSTEMI).Methods OCT was used in elderly patients undergoing percutaneous coronary interventions.Fifteen patients,9 males and 6 females with mean age of 72.6±5.3 years(range 67-92 years)were enrolled in the study.Images were obtained before initial balloon dilatation and following stent deployment.The plaque characteristics before dilation,vessel dissection,tissue prolapse,stent apposition and strut distribution after stent implantation were evaluated.Results Fifteen lesions were selected from 32 angiographic lesions as study lesions for OCT imaging after diagnostic coronary angiography.There were 7 lesions in the left anterior descending artery,5 lesions in the right coronary artery and 3 lesions in the left circumflex coronary artery.Among them,12(80.0%)were lipid-rich plaques,and 10(66.7%)were vulnerable plaques with fibrous cap thickness 54.2±7.3μm.Seven ruptured culprit plaques(46.7%)were found;4 in UA patients and 3 in NSTEMI patients.Tissue prolapse was observed in 11 lesions(73.3%).Irregular stent strut distribution was detected in 8 lesions(53.3%).Vessel dissections were found in 5 lesions(33.3%).Incomplete stent apposition was observed in 3 stents(20%)with mean spacing between the struts and the vessel wall 172±96 mm(range 117-436 mm).Conclusions 1)It is safe and feasible to perform intravascular OCT to differentiate vulnerable coronary plaque and monitor stent deployment in elderly patients with UA and USTEMI.2)Coronary plaques in elderly patients with UA and USTEMI could be divided into acute ruptured plaque,vulnerable plaque,lipid-rich plaque,and stable plaque.3)Minor or critical plaque rupture is one of the mechanisms of UA in elderly patients.4)Present drug eluting stent implantation is complicated with multiple tissue prolapses which are associated with irregular strut distributions.5)The action and significance of tissue prolapse on acute vessel flow and in-stent thrombus and restenosis need to be further studied.展开更多
Objective:To evaluate the detection of IgM and IgG antibodies to Orientia tsutsugamushi(O. tsutsugamushi) by rapid diagnostic test(RDT) and microimmunofluorescence assay(ml FA). Methods:RDT using a mixture of recombin...Objective:To evaluate the detection of IgM and IgG antibodies to Orientia tsutsugamushi(O. tsutsugamushi) by rapid diagnostic test(RDT) and microimmunofluorescence assay(ml FA). Methods:RDT using a mixture of recombinant 56-kDa proteins of O.tsutsugamushi and mIFA assay were performed on 20 patients from Fujian and 13 patients from Yunnan Province,and 82 sera samples from healthy farmers in Anhui Province and Beijing City in 2009.Comparison of the RDT and mIFA assay was performed by using X test and the P level of 【0.05 was considered to be significance.Results:Among these 82 normal sera samples,the specificity of RDT was 100%for both IgM and IgG tests.In 33 samples from patients with scrub typhus,5 cases were positively detected earlier by RDT than by mIFA in IgM test,and 2 cases were positive in IgG test.Sensitivities of RDT were 93.9%and 90.9%for IgM and IgG,respectively.The sensitivity of combination lest of IgM and IgG was 100%.Geometric mean titer diluted sera from confirmed cases by IFA and RDT assay were 1:37 vs.1:113(P【0.001) in IgM test and 1:99 vs.1:279 (P【0.05) in IgG test.Conclusions:RDT is more sensitivite than mIFA in the early diagnosis of scrub typhus and it is particularly applicable in rural areas.展开更多
Chemical doping is a powerful method to intrinsically tailor the electrochemical properties of electrode materials.Here,an interstitial boron-doped tunnel-type VO_(2)(B)is constructed via a facile hydrothermal method....Chemical doping is a powerful method to intrinsically tailor the electrochemical properties of electrode materials.Here,an interstitial boron-doped tunnel-type VO_(2)(B)is constructed via a facile hydrothermal method.Various analysis techniques demonstrate that boron resides in the interstitial site of VO_(2)(B)and such interstitial doping can boost the zinc storage kinetics and structural stability of VO_(2)(B)cathode during cycling.Interestingly,we found that the boron doping level has a saturation limit peculiarity as proved by the quantitative analysis.Notably,the 2 at.%boron-doped VO_(2)(B)shows enhanced zinc ion storage performance with a high storage capacity of 281.7 mAh g^(-1) at 0.1 A g^(-1),excellent rate performance of 142.2 mAh g^(-1) at 20 A g^(-1),and long cycle stability up to 1000 cycles with the capacity retention of 133.3 mAh g^(-1) at 5 A g^(-1).Additionally,the successful preparation of the boron-doped tunneltype α-MnO_(2) further indicates that the interstitial boron doping approach is a general strategy,which supplies a new chance to design other types of functional electrode materials for multivalence batteries.展开更多
Background and Objectives The relationship between left atrial(LA)size and congestive heart failure(CHF)is well recognized;however,there is little information on the association of pulmonary vein(PV)diameter and CHF.T...Background and Objectives The relationship between left atrial(LA)size and congestive heart failure(CHF)is well recognized;however,there is little information on the association of pulmonary vein(PV)diameter and CHF.The purpose of this study was to investigate the changes of PV and LA sizes in CHF patients by multislice computed tomography(MSCT)angiography using a new 64-slice scanner.Methods and Results We assessed diameters of PVs ostium and LA by 64-slice MSCT with three-dimensional reconstruction in 25 CHF patients and in 26 age-and sex-matched non-CHF controls.Compared with controls,CHF patients showed significant greater diameters of left superior pulmonary vein(LSPV)and right inferior pulmonary vein(RIPV)in both anteriorposterior(AP)and superior-inferior(SI)directions(P<0.01),significant dilation of right superior pulmonary vein(RSPV)in AP direction(P<0.05),as well as significant increase of LA transverse,AP,and SI diameters(P<0.01).Conclusion Significant dilation of PVs with simultaneous LA enlargement was demonstrated in CHF patients.This anatomic and geometric changes may participate in the perpetuation of AF.展开更多
Objectives:To report the clinical experience of combined interventional procedures in the treatment of elderly patients with coexisting two or more cardiovascular diseases in our medical center,and to assess the feasi...Objectives:To report the clinical experience of combined interventional procedures in the treatment of elderly patients with coexisting two or more cardiovascular diseases in our medical center,and to assess the feasibility,safety and therapeutic efficacy of this management strategy.Methods:Patients were selected to the study if:1)age>65 years;2)with coexistence of two or more cardiovascular diseases which are indications for interventional therapy;3)patients'general condition and organ functions allow the performance of combined multiple procedures;4)the predicted procedure time is within 150 min;5)the predicted contrast medium dosage is within 300 ml.The criteria we analyzed included procedural type,rocedural time,fluoroscopy time,dosage of contrast medium,success rates of the procedures,complications and in-hospital mortality.All patients were followed up for 30.4±9.3 months,to determine the all-cause mortality,recurrence rates and adverse cardiac events.Results:From January 2000 to December 2004,combined interventional procedures were performed on 136 patients,with 2 procedures on 134 patients and 3 procedures on 2 patients.The mean procedure time was 115.4±11.6 min,the mean fluoroscopy time was 35.7±9.3 min,and the mean dosage of contrast medium used was 183.6±19.4 ml.Procedural success rate was 100%,no procedure related death or major complications occurred.Conclusion:Performed by a competent team,combined interventional procedures in elderly patients with multiple cardiovascular diseases were feasible and relatively safe.展开更多
Objective To evaluate the feasibility,safety and efficacy of percutaneous stent implantation for treating left main coronary artery(LMCA)stenosis.Methods Consecutive patients with unprotected left main coronary artery...Objective To evaluate the feasibility,safety and efficacy of percutaneous stent implantation for treating left main coronary artery(LMCA)stenosis.Methods Consecutive patients with unprotected left main coronary artery disease treated by stent-based percutaneous intervention(PCI)at 6 medical centers in China were enrolled.Procedural data and clinical outcomes were obtained from all patients.Results From January 2001 to December 2004,138 patients(79 males and 59 females;mean age:69.7±5.8 years)underwent PCI for LMCA stenosis.Bare metal stents(BMS)were implanted in 51 patients with non-bifurcational lesions and in 5 patients with bifurcational lesions from January of 2001 to June of 2003(BMS group);.Drug eluting stents(DES)were used unselectively to cover both bifurcational and non-bifurcational lesions in 86 patients from July of 2003 to December of 2004(DES group).Procedural success rate of the 138 cases was 98%(135/138).One patient(0.7%)with bifurcation lesion who was treated with DES died from severe heart failure 2 weeks after the procedure.During a mean follow up period of 21.3±5.6 months,one patient died from renal failure,one from sudden cardiac death,4 underwent target lesion revascularization(TLR)in the BMS group,which all occurred in patients with bifurcational lesions;whereas in the DES group no deaths occurred and only one patient with bifurcational lesion had TLR.Conclusions(1)PCI is feasible and relatively safe to treat unprotected left main coronary artery disease in elderly patients at medical centers with experienced professionals.(2)BMS and DES have similar immediate and long-term efficacy in the treatment of ostium and shaft lesions of the LMCA.(3)DES are strongly suggested in the therapy of distal bifurcation lesion of unprotected LMCA.展开更多
Multiple organ dysfunction syndrome in the elderly (MODSE) is an important syndrome in the critical care of elderly patients. MODSE is defined as simultaneous or sequential dysfunction or failure of two or more organs...Multiple organ dysfunction syndrome in the elderly (MODSE) is an important syndrome in the critical care of elderly patients. MODSE is defined as simultaneous or sequential dysfunction or failure of two or more organs on the top of advanced age and chronic multiple organ dysfunction. MODSE is triggered by precipitating factors such as infection (usually pulmonary infection) trauma,surgery, etc. It occurs in two phases. In the early phase, dysfunction of multiple organs (MODE) occurs,and in the later or severe phase, multiple organ failure (MOFE) occurs. MODSE is the most common cause of mortality in the critically iii elderly patient. It is important to understand its clinical characteristics and elucidate its pathogenesis in order to reduce mortality and improve quality of life for these patients.展开更多
Objective:The hyperactivated neddylation pathway plays an important role in tumorigenesis and is emerging as a promising anticancer target.We aimed to study whether NEDD8(neural precursor cell expressed,developmentall...Objective:The hyperactivated neddylation pathway plays an important role in tumorigenesis and is emerging as a promising anticancer target.We aimed to study whether NEDD8(neural precursor cell expressed,developmentally down-regulated 8)might serve as a therapeutic target in esophageal squamous cell carcinoma(ESCC).Methods:The clinical relevance of NEDD8 expression was evaluated by using The Cancer Genome Atlas(TCGA)database and tissue arrays.NEDD8-knockdown ESCC cells generated with the CRISPR/Cas9 system were used to explore the anticancer effects and mechanisms.Quantitative proteomic analysis was used to examine the variations in NEDD8 knockdown-induced biological pathways.The cell cycle and apoptosis were assessed with fluorescence activated cell sorting.A subcutaneous-transplantation mouse tumor model was established to investigate the anticancer potential of NEDD8 silencing in vivo.Results:NEDD8 was upregulated at both the mRNA and protein expression levels in ESCC,and NEDD8 overexpression was associated with poorer overall patient survival(mRNA level:P=0.028,protein level:P=0.026,log-rank test).Downregulation of NEDD8 significantly suppressed tumor growth both in vitro and in vivo.Quantitative proteomic analysis revealed that downregulation of NEDD8 induced cell cycle arrest,DNA damage,and apoptosis in ESCC cells.Mechanistic studies demonstrated that NEDD8 knockdown led to the accumulation of cullin-RING E3 ubiquitin ligases(CRLs)substrates through inactivation of CRLs,thus suppressing the malignant phenotype by inducing cell cycle arrest and apoptosis in ESCC.Rescue experiments demonstrated that the induction of apoptosis after NEDD8 silencing was attenuated by DR5 knockdown.Conclusions:Our study elucidated the anti-ESCC effects and underlying mechanisms of NEDD8 knockdown,and validated NEDD8 as a potential target for ESCC therapy.展开更多
Objective To define the heterogeneous changes of ion channels in the noninfarcted myocardium after myocardial infarction in rabbit and effects of imidapril.Mehods Rabbits with left coronary artery ligation were prepar...Objective To define the heterogeneous changes of ion channels in the noninfarcted myocardium after myocardial infarction in rabbit and effects of imidapril.Mehods Rabbits with left coronary artery ligation were prepared and allowed to recover for 8 wk.Myocytes were isolated from subendocardial,midmyocardial and subepicardial regions of the noninfarcted left ventricular free wall.Ion currents were recorded with whole-cell patch clamp way.Results The densities of the transient outward K^(+)currents(I_(to))and the inward rectifier K^(+)currents(I_(K1))were greatly reduced in midmyocardium and subepicardium while two currents reduced gently in subendocardium.The densities of the delayed rectifier K^(+)currents(I_(K))were reduced in noninfarcted three layers similarly.Imidapril could reverse the changes of membrane currents in healed myocardial infarction cells and depress the dispersion of repolarization.Conclusions The heterogeneities of K currents are enhanced in noninfarcted area.Normalization of heterogeneous changes of repolarization after treatment with imidapril was observed.展开更多
Objective To investigate the occurrence of nocturnal myocardial ischemia and its relationship with sleep-disordered breathing (apneas and oxygen desaturations) in patients with angina pectoris undergoing coronary angi...Objective To investigate the occurrence of nocturnal myocardial ischemia and its relationship with sleep-disordered breathing (apneas and oxygen desaturations) in patients with angina pectoris undergoing coronary angiography.Methods Eighty-two men and 14 women referred for consideration of coronary intervention were randomly selected. Observation by an overnight sleep monitor and Holter recording were performed to study sleep-disordered breathing (oxyhemoglobin desaturations≥4% and apnea-hypopneas),heart rates, and ST-segment depressions (≥ 1mm, ≥1 min).Results Nocturnal ST-segment depressions occurred in 37 % of the patients. ST-segment depression within 2 min after an apnea-hypopnea or desaturation occurred in 17% of the patients. This temporal association was seen in 21% of the patients with nocturnal ST-segment depressions, more frequently in men (P<0.05) and more frequently in those with severe disordered breathing (P<0.05).Most of these ST-segment depressions were preceded by a series of breathing events: repeated apnea-hypopneas or desaturations or both in 73% of the patients. Conclusions Episodes of nocturnal myocardial ischemia are common in patients with angina pectoris. A temporal relationship between sleep-disordered breathing and myocardial ischemia was present in some of our patients, and occurs more frequently in men and in those with severely disordered breathing. (J Geriatr Cardiol 2004;1(2):90-94.)展开更多
Chronic heart failure (CHF) is a clinical syndrome as a common pathway at the end stage of cardiac diseases of different etiologies, and it is currently the only cardiovascular disease with an increasing prevalenc... Chronic heart failure (CHF) is a clinical syndrome as a common pathway at the end stage of cardiac diseases of different etiologies, and it is currently the only cardiovascular disease with an increasing prevalence in the developed countries. In the United States, the prevalence of CHF at age 50 years is 1.0%, whereas it reaches 7.5% at age 80years. In the United Kingdom, the prevalence of CHF is5.0% at age 60-70 years, and 10-20% at age 80 years. The situation is similar in Italy and Portugal. Despite being a developing country in Asia, China has experienced rapid progress in acquiring medical knowledge and advancing techniques in recent years. Due to the markedly declined mortality of acute myocardial infarction (AMI) as well as the aging of Chinese population, about four million Chinese have CHF with a prevalence of 0.9%, most of whom are 60 years of age and older.……展开更多
Good morning, ladies and gentlemen,
In the golden autumn of Beijing, on behalf of the Organizing Committee of the Great Wall International Congress of Cardiology, and the Institute of Geriatric Cardiology at ... Good morning, ladies and gentlemen,
In the golden autumn of Beijing, on behalf of the Organizing Committee of the Great Wall International Congress of Cardiology, and the Institute of Geriatric Cardiology at Chinese PLA General Hospital, I am very delighted to extend my warmest welcome to the representatives, colleagues and distinguished guests, both domestic and abroad, to the 5th International Forum on Geriatric Cardiology.……展开更多
The advent of the Journal of Geriatric Cardiology set up jointly by Chinese and American scholars is an important event in geriatric cardiology with historical significance in China.
Transitory starch is an important carbon source in leaves,and its biosynthesis and metabolism are closely related to grain quality and yield.The molecular mechanisms controlling leaf transitory starch biosynthesis and...Transitory starch is an important carbon source in leaves,and its biosynthesis and metabolism are closely related to grain quality and yield.The molecular mechanisms controlling leaf transitory starch biosynthesis and degradation and their effects on rice(Oryza sativa)quality and yield remain unclear.Here,we show that OsLESV and OsESV1,the rice orthologs of AtLESV and AtESV1,are associated with transitory starch biosynthesis in rice.The total starch and amylose contents in leaves and endosperms are significantly reduced,and the final grain quality and yield are compromised in oslesv and osesv1 single and oslesv esv1 double mutants.Furthermore,we found that OsLESV and OsESV1 bind to starch,and this binding depends on a highly conserved C-terminal tryptophan-rich region that acts as a starch-binding domain.Importantly,OsLESV and OsESV1 also interact with the key enzymes of starch biosynthesis,granule-bound starch synthase I(GBSSI),GBSSII,and pyruvate orthophosphote dikiase(PPDKB),to maintain their protein stability and activity.OsLESV and OsESV1 also facilitate the targeting of GBSSI and GBSSII from plastid stroma to starch granules.Overexpression of GBSSI,GBSSII,and PPDKB can partly rescue the phenotypic defects of the oslesv and osesv1 mutants.Thus,we demonstrate that OsLESV and OsESV1 play a key role in regulating the biosynthesis of both leaf transitory starch and endosperm storage starch in rice.These findings deepen our understanding of the molecular mechanisms underlying transitory starch biosynthesis in rice leaves and reveal how the transitory starch metabolism affects rice grain quality and yield,providing useful information for the genetic improvement of rice grain quality and yield.展开更多
What is already known about this topic?Mucosal IgA plays a crucial role in host immunity against respiratory viruses.Recent studies suggest that it has the potential to mitigate the transmission of the severe acute re...What is already known about this topic?Mucosal IgA plays a crucial role in host immunity against respiratory viruses.Recent studies suggest that it has the potential to mitigate the transmission of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)Omicron variant.However,a comprehensive population-based analysis examining mucosal IgA levels following the winter 2022 wave of the coronavirus disease 2019(COVID-19)pandemic is yet to be conducted.What is added by this report?In our study involving 3,421 participants,we documented IgA responses subsequent to SARS-CoV-2 infection.A significant proportion of individuals sustained increased levels of IgA for over six months.These levels were also observed in individuals with prior infections who underwent asymptomatic reinfections,indicating an active production of IgA antibodies.Further,individuals with multiple vaccinations or severe symptoms tended to display elevated IgA levels after recovery.What are the implications for public health practice?IgA in the nasal mucosa is crucial for defense against SARS-CoV-2 infection.These insights can enhance our knowledge of immune responses following infection and have provided certain reference values for disease prevention and control strategies.展开更多
基金supported by the National Key Research and Development Program(No.2022YFB4202200)the Fundamental Research Funds for the Central Universities.
文摘Green hydrogen(H_(2))produced by renewable energy powered alkaline water electrolysis is a promising alternative to fossil fuels due to its high energy density with zero-carbon emissions.However,efficient and economic H_(2) production by alkaline water electrolysis is hindered by the sluggish hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Therefore,it is imperative to design and fabricate high-active and low-cost non-precious metal catalysts to improve the HER and OER performance,which affects the energy efficiency of alkaline water electrolysis.Ni_(3)S_(2) with the heazlewoodite structure is a potential electrocatalyst with near-metal conductivity due to the Ni–Ni metal network.Here,the review comprehensively presents the recent progress of Ni_(3)S_(2)-based electrocatalysts for alkaline water electrocatalysis.Herein,the HER and OER mechanisms,performance evaluation criteria,preparation methods,and strategies for performance improvement of Ni_(3)S_(2)-based electrocatalysts are discussed.The challenges and perspectives are also analyzed.
基金supported by the National Basic Research Program of China(973 Program) 2010CB530200(2010CB530206)the National Natural Science Foundation of China(No.30771854)National Key Science and Technology Projects of China(Project No.2008ZX10004-008)
文摘Objective:To investigate the situation of anaplasmosis in Yiyuan county.Shandong Province. Methods:A total of 26 blood samples from febrile patients suspected of anaplasmosis,48 blood samples from healthy farmers,8 from dogs,and 10 from goats and 170 ticks were collected in the same area during 2005-2007,and detected by serological and molecular methods.Results: Eight confirmed cases and 6 probable cases were determined using serologic and molecular methods.The seroprevalence of Anaplasma phagocytophilum(A.phagocytophilum) was 26.7% in healthy cases.Nine out of 10 sheep samples and 7 out of 8 dog samples reacted positively to the A.phagocytophilum antigen.PCR amplification and sequencing of the 16SrRNA of,4. phagocytophilum gene showed that some samples from patients,goats and ticks were 100% identical.The seroprevalence of Rickettsia typhi was 22.9%,Orientia tsutsugamushi 6.3%, Rickettsia sibirica 27.1%,Coxiella burnetii 18.8%,Bartonella henselae 31.3%,and Borrelia burgdorferi 41.6%.Conclusions:It is important to make differential diagnosis of febrile patients and to apply treatment with specific antibiotics.It is needed to enforce essential prevention and control measures including tick control and to improve sanitation conditions.
基金supported by the National Basic Research Program of China(973 Program)2010CB530200(2010CB530206)the China-US Collaborative Program on Emerging and Re-emerging Infectious Disease(No.1U2GGH000018-01)
文摘Objective:To evaluate the Anaplasma phagocytophilum(A.phagocytophilum),Ehrlichia canis(E.canis,Dirofilaria immitis(D.immitis)(canine heartworm),Borrelia burgdorferi(B.burgdorferi)infections in countryside dogs from Yunnan,Hainan and Anhui provinces.Methods:Serum samples were collected from 26 dogs in Yunnan.Hainan and Anhui provinces.The samples were tested using a commercial ELISA rapid diagnostic assay kit(SNAP^(?)4Dx^(?);IDEXX Laboratories,Inc.U.S.A.).Meaiiwliile,indirect immunofluorescence assay(IFA)recommended by WHO was conducted to delect IgG to A.phagocytophilum.Two methods were analyzed and compared.Results:The number of serologically positive dogs for IgG to A.phagocytophilum was only 2which was from Hainan province and none of the 26 dogs responded positive for E.canu.D.immitis(canine heartworm,and B.burgdorferi by ELISA rapid diagnostic method.The number of serologically positive dogs for IgG to A.phagocytophilum was 13(50%)by IFA method.Data of the two methods were analyzed by statistical software and the difference was statistically significant(P=0.002).Conclusions:It can be concluded that IFA method was more sensitive than ELISA rapid diagnostic method.However,we need conduct further and intensive epidemiology survey on tick-born diseases pathogens including.4.phagocytophilum,E.canis,D.immitis(canine heartworm),and B.burgdorferi which have public health significance.
基金supported by the National Basic Research Program of China(2015CB150402)the National Key Technology R&D Program(2015BAD22B01)111 project of Chinese Education Ministry(B12007)。
文摘Erratic rainfall and misalignment between the rainy season and the growing season of winter wheat greatly limit rainfed winter wheat yield in the Loess Plateau of China. To increase the grain yield of winter wheat in this region, the effects of different agronomic practices, including adjusting planting pattern(NR, narrow row spacing), increasing seeding rate(high seeding rate, HS), decreasing basal nitrogen rate and increasing top-dressed nitrogen rate(DBN), and replacing an old cultivar with a new cultivar(NC) on wheat yield were investigated for two consecutive years. The results showed that the current grain yield of rainfed winter wheat in the Loess Plateau could be increased to 5879–7093 kg ha^(-1) by HS, DBN and NC practices relative to the practice of high-yielding farmers(PF). The increased yield due to HS, DBN and NC was attributed to the higher number of spikes ha^(-1), 1000-grain weight, and kernels spike^(-1). Before the flowering stage, HS increased soil water consumption(SWC) in 1–3 m subsoil due to the higher plant population compared with that of PF, whereas DBN decreased SWC in the 0–2 m soil layer compared with that of PF. After the flowering stage, HS, DBN, and NC increased SWC by 8–16 mm in 2–3 m subsoil compared to PF. The water use efficiency(WUE) was increased under DBN and NC in comparison with PF.However, the WUE did not increase under HS as it had the highest evapotranspiration among the five treatments. Increasing the use of subsoil water during the late growth stage by optimizing agronomic practices or applying new cultivars with expansive roots should be the primary approach to increase rainfed winter wheat yield in this region.
基金This work is supported by China Capital Medical Development Fund(C03030201).
文摘Objective To evaluate the feasibility and efficacy of intravascular optical coherence tomography(OCT)in the assessment of plaque characteristics and drug eluting stent deployment quality in the elderly patients with unstable angina(UA)and non-ST segment elevation myocardial infarction(NSTEMI).Methods OCT was used in elderly patients undergoing percutaneous coronary interventions.Fifteen patients,9 males and 6 females with mean age of 72.6±5.3 years(range 67-92 years)were enrolled in the study.Images were obtained before initial balloon dilatation and following stent deployment.The plaque characteristics before dilation,vessel dissection,tissue prolapse,stent apposition and strut distribution after stent implantation were evaluated.Results Fifteen lesions were selected from 32 angiographic lesions as study lesions for OCT imaging after diagnostic coronary angiography.There were 7 lesions in the left anterior descending artery,5 lesions in the right coronary artery and 3 lesions in the left circumflex coronary artery.Among them,12(80.0%)were lipid-rich plaques,and 10(66.7%)were vulnerable plaques with fibrous cap thickness 54.2±7.3μm.Seven ruptured culprit plaques(46.7%)were found;4 in UA patients and 3 in NSTEMI patients.Tissue prolapse was observed in 11 lesions(73.3%).Irregular stent strut distribution was detected in 8 lesions(53.3%).Vessel dissections were found in 5 lesions(33.3%).Incomplete stent apposition was observed in 3 stents(20%)with mean spacing between the struts and the vessel wall 172±96 mm(range 117-436 mm).Conclusions 1)It is safe and feasible to perform intravascular OCT to differentiate vulnerable coronary plaque and monitor stent deployment in elderly patients with UA and USTEMI.2)Coronary plaques in elderly patients with UA and USTEMI could be divided into acute ruptured plaque,vulnerable plaque,lipid-rich plaque,and stable plaque.3)Minor or critical plaque rupture is one of the mechanisms of UA in elderly patients.4)Present drug eluting stent implantation is complicated with multiple tissue prolapses which are associated with irregular strut distributions.5)The action and significance of tissue prolapse on acute vessel flow and in-stent thrombus and restenosis need to be further studied.
基金supported by the National Basil Research Program of China(973 Program) 2010CBS30200(2010CB530206)the grants from the National Key Science and Technolog Projects of China,No.2009ZX10004-203 and 2008ZX10004-008)
文摘Objective:To evaluate the detection of IgM and IgG antibodies to Orientia tsutsugamushi(O. tsutsugamushi) by rapid diagnostic test(RDT) and microimmunofluorescence assay(ml FA). Methods:RDT using a mixture of recombinant 56-kDa proteins of O.tsutsugamushi and mIFA assay were performed on 20 patients from Fujian and 13 patients from Yunnan Province,and 82 sera samples from healthy farmers in Anhui Province and Beijing City in 2009.Comparison of the RDT and mIFA assay was performed by using X test and the P level of 【0.05 was considered to be significance.Results:Among these 82 normal sera samples,the specificity of RDT was 100%for both IgM and IgG tests.In 33 samples from patients with scrub typhus,5 cases were positively detected earlier by RDT than by mIFA in IgM test,and 2 cases were positive in IgG test.Sensitivities of RDT were 93.9%and 90.9%for IgM and IgG,respectively.The sensitivity of combination lest of IgM and IgG was 100%.Geometric mean titer diluted sera from confirmed cases by IFA and RDT assay were 1:37 vs.1:113(P【0.001) in IgM test and 1:99 vs.1:279 (P【0.05) in IgG test.Conclusions:RDT is more sensitivite than mIFA in the early diagnosis of scrub typhus and it is particularly applicable in rural areas.
基金Key R&D projects of Henan Province,Grant/Award Number:221111240600National Natural Science Foundation of China,Grant/Award Numbers:U1704256,52272243,52202316+2 种基金Natural Science Foundation of Henan Province,Grant/Award Numbers:212300410300,212300410416PhD Research Fund Project,Grant/Award Number:13501050089School Key Project,Zhengzhou University of Light Industry,Grant/Award Number:2021ZDPY0203。
文摘Chemical doping is a powerful method to intrinsically tailor the electrochemical properties of electrode materials.Here,an interstitial boron-doped tunnel-type VO_(2)(B)is constructed via a facile hydrothermal method.Various analysis techniques demonstrate that boron resides in the interstitial site of VO_(2)(B)and such interstitial doping can boost the zinc storage kinetics and structural stability of VO_(2)(B)cathode during cycling.Interestingly,we found that the boron doping level has a saturation limit peculiarity as proved by the quantitative analysis.Notably,the 2 at.%boron-doped VO_(2)(B)shows enhanced zinc ion storage performance with a high storage capacity of 281.7 mAh g^(-1) at 0.1 A g^(-1),excellent rate performance of 142.2 mAh g^(-1) at 20 A g^(-1),and long cycle stability up to 1000 cycles with the capacity retention of 133.3 mAh g^(-1) at 5 A g^(-1).Additionally,the successful preparation of the boron-doped tunneltype α-MnO_(2) further indicates that the interstitial boron doping approach is a general strategy,which supplies a new chance to design other types of functional electrode materials for multivalence batteries.
文摘Background and Objectives The relationship between left atrial(LA)size and congestive heart failure(CHF)is well recognized;however,there is little information on the association of pulmonary vein(PV)diameter and CHF.The purpose of this study was to investigate the changes of PV and LA sizes in CHF patients by multislice computed tomography(MSCT)angiography using a new 64-slice scanner.Methods and Results We assessed diameters of PVs ostium and LA by 64-slice MSCT with three-dimensional reconstruction in 25 CHF patients and in 26 age-and sex-matched non-CHF controls.Compared with controls,CHF patients showed significant greater diameters of left superior pulmonary vein(LSPV)and right inferior pulmonary vein(RIPV)in both anteriorposterior(AP)and superior-inferior(SI)directions(P<0.01),significant dilation of right superior pulmonary vein(RSPV)in AP direction(P<0.05),as well as significant increase of LA transverse,AP,and SI diameters(P<0.01).Conclusion Significant dilation of PVs with simultaneous LA enlargement was demonstrated in CHF patients.This anatomic and geometric changes may participate in the perpetuation of AF.
文摘Objectives:To report the clinical experience of combined interventional procedures in the treatment of elderly patients with coexisting two or more cardiovascular diseases in our medical center,and to assess the feasibility,safety and therapeutic efficacy of this management strategy.Methods:Patients were selected to the study if:1)age>65 years;2)with coexistence of two or more cardiovascular diseases which are indications for interventional therapy;3)patients'general condition and organ functions allow the performance of combined multiple procedures;4)the predicted procedure time is within 150 min;5)the predicted contrast medium dosage is within 300 ml.The criteria we analyzed included procedural type,rocedural time,fluoroscopy time,dosage of contrast medium,success rates of the procedures,complications and in-hospital mortality.All patients were followed up for 30.4±9.3 months,to determine the all-cause mortality,recurrence rates and adverse cardiac events.Results:From January 2000 to December 2004,combined interventional procedures were performed on 136 patients,with 2 procedures on 134 patients and 3 procedures on 2 patients.The mean procedure time was 115.4±11.6 min,the mean fluoroscopy time was 35.7±9.3 min,and the mean dosage of contrast medium used was 183.6±19.4 ml.Procedural success rate was 100%,no procedure related death or major complications occurred.Conclusion:Performed by a competent team,combined interventional procedures in elderly patients with multiple cardiovascular diseases were feasible and relatively safe.
文摘Objective To evaluate the feasibility,safety and efficacy of percutaneous stent implantation for treating left main coronary artery(LMCA)stenosis.Methods Consecutive patients with unprotected left main coronary artery disease treated by stent-based percutaneous intervention(PCI)at 6 medical centers in China were enrolled.Procedural data and clinical outcomes were obtained from all patients.Results From January 2001 to December 2004,138 patients(79 males and 59 females;mean age:69.7±5.8 years)underwent PCI for LMCA stenosis.Bare metal stents(BMS)were implanted in 51 patients with non-bifurcational lesions and in 5 patients with bifurcational lesions from January of 2001 to June of 2003(BMS group);.Drug eluting stents(DES)were used unselectively to cover both bifurcational and non-bifurcational lesions in 86 patients from July of 2003 to December of 2004(DES group).Procedural success rate of the 138 cases was 98%(135/138).One patient(0.7%)with bifurcation lesion who was treated with DES died from severe heart failure 2 weeks after the procedure.During a mean follow up period of 21.3±5.6 months,one patient died from renal failure,one from sudden cardiac death,4 underwent target lesion revascularization(TLR)in the BMS group,which all occurred in patients with bifurcational lesions;whereas in the DES group no deaths occurred and only one patient with bifurcational lesion had TLR.Conclusions(1)PCI is feasible and relatively safe to treat unprotected left main coronary artery disease in elderly patients at medical centers with experienced professionals.(2)BMS and DES have similar immediate and long-term efficacy in the treatment of ostium and shaft lesions of the LMCA.(3)DES are strongly suggested in the therapy of distal bifurcation lesion of unprotected LMCA.
文摘Multiple organ dysfunction syndrome in the elderly (MODSE) is an important syndrome in the critical care of elderly patients. MODSE is defined as simultaneous or sequential dysfunction or failure of two or more organs on the top of advanced age and chronic multiple organ dysfunction. MODSE is triggered by precipitating factors such as infection (usually pulmonary infection) trauma,surgery, etc. It occurs in two phases. In the early phase, dysfunction of multiple organs (MODE) occurs,and in the later or severe phase, multiple organ failure (MOFE) occurs. MODSE is the most common cause of mortality in the critically iii elderly patient. It is important to understand its clinical characteristics and elucidate its pathogenesis in order to reduce mortality and improve quality of life for these patients.
基金This work was supported by grants from the National Natural Science Foundation of China(Grant Nos.81602072,81902380,81820108022,and 81625018)Innovation Program of Shanghai Municipal Education Commission(Grant No.2019-01-07-00-10-E00056)+5 种基金Program of Shanghai Academic/Technology Research Leader(Grant No.18XD1403800)National High Technology Research and Development Program of China(Grant No.2015AA021107-019)Scientific Research Project of Shanghai Science and Technology Commission(Grant No.18411960600)Shanghai Technological Innovation Action Projects(Grant No.18411950800)Shanghai‘Rising Stars of Medical Talent’Youth Development Program,Outstanding Youth Medical Talents,2018the Shanghai Sailing Program(Grant No.17YF1405000).
文摘Objective:The hyperactivated neddylation pathway plays an important role in tumorigenesis and is emerging as a promising anticancer target.We aimed to study whether NEDD8(neural precursor cell expressed,developmentally down-regulated 8)might serve as a therapeutic target in esophageal squamous cell carcinoma(ESCC).Methods:The clinical relevance of NEDD8 expression was evaluated by using The Cancer Genome Atlas(TCGA)database and tissue arrays.NEDD8-knockdown ESCC cells generated with the CRISPR/Cas9 system were used to explore the anticancer effects and mechanisms.Quantitative proteomic analysis was used to examine the variations in NEDD8 knockdown-induced biological pathways.The cell cycle and apoptosis were assessed with fluorescence activated cell sorting.A subcutaneous-transplantation mouse tumor model was established to investigate the anticancer potential of NEDD8 silencing in vivo.Results:NEDD8 was upregulated at both the mRNA and protein expression levels in ESCC,and NEDD8 overexpression was associated with poorer overall patient survival(mRNA level:P=0.028,protein level:P=0.026,log-rank test).Downregulation of NEDD8 significantly suppressed tumor growth both in vitro and in vivo.Quantitative proteomic analysis revealed that downregulation of NEDD8 induced cell cycle arrest,DNA damage,and apoptosis in ESCC cells.Mechanistic studies demonstrated that NEDD8 knockdown led to the accumulation of cullin-RING E3 ubiquitin ligases(CRLs)substrates through inactivation of CRLs,thus suppressing the malignant phenotype by inducing cell cycle arrest and apoptosis in ESCC.Rescue experiments demonstrated that the induction of apoptosis after NEDD8 silencing was attenuated by DR5 knockdown.Conclusions:Our study elucidated the anti-ESCC effects and underlying mechanisms of NEDD8 knockdown,and validated NEDD8 as a potential target for ESCC therapy.
文摘Objective To define the heterogeneous changes of ion channels in the noninfarcted myocardium after myocardial infarction in rabbit and effects of imidapril.Mehods Rabbits with left coronary artery ligation were prepared and allowed to recover for 8 wk.Myocytes were isolated from subendocardial,midmyocardial and subepicardial regions of the noninfarcted left ventricular free wall.Ion currents were recorded with whole-cell patch clamp way.Results The densities of the transient outward K^(+)currents(I_(to))and the inward rectifier K^(+)currents(I_(K1))were greatly reduced in midmyocardium and subepicardium while two currents reduced gently in subendocardium.The densities of the delayed rectifier K^(+)currents(I_(K))were reduced in noninfarcted three layers similarly.Imidapril could reverse the changes of membrane currents in healed myocardial infarction cells and depress the dispersion of repolarization.Conclusions The heterogeneities of K currents are enhanced in noninfarcted area.Normalization of heterogeneous changes of repolarization after treatment with imidapril was observed.
文摘Objective To investigate the occurrence of nocturnal myocardial ischemia and its relationship with sleep-disordered breathing (apneas and oxygen desaturations) in patients with angina pectoris undergoing coronary angiography.Methods Eighty-two men and 14 women referred for consideration of coronary intervention were randomly selected. Observation by an overnight sleep monitor and Holter recording were performed to study sleep-disordered breathing (oxyhemoglobin desaturations≥4% and apnea-hypopneas),heart rates, and ST-segment depressions (≥ 1mm, ≥1 min).Results Nocturnal ST-segment depressions occurred in 37 % of the patients. ST-segment depression within 2 min after an apnea-hypopnea or desaturation occurred in 17% of the patients. This temporal association was seen in 21% of the patients with nocturnal ST-segment depressions, more frequently in men (P<0.05) and more frequently in those with severe disordered breathing (P<0.05).Most of these ST-segment depressions were preceded by a series of breathing events: repeated apnea-hypopneas or desaturations or both in 73% of the patients. Conclusions Episodes of nocturnal myocardial ischemia are common in patients with angina pectoris. A temporal relationship between sleep-disordered breathing and myocardial ischemia was present in some of our patients, and occurs more frequently in men and in those with severely disordered breathing. (J Geriatr Cardiol 2004;1(2):90-94.)
文摘 Chronic heart failure (CHF) is a clinical syndrome as a common pathway at the end stage of cardiac diseases of different etiologies, and it is currently the only cardiovascular disease with an increasing prevalence in the developed countries. In the United States, the prevalence of CHF at age 50 years is 1.0%, whereas it reaches 7.5% at age 80years. In the United Kingdom, the prevalence of CHF is5.0% at age 60-70 years, and 10-20% at age 80 years. The situation is similar in Italy and Portugal. Despite being a developing country in Asia, China has experienced rapid progress in acquiring medical knowledge and advancing techniques in recent years. Due to the markedly declined mortality of acute myocardial infarction (AMI) as well as the aging of Chinese population, about four million Chinese have CHF with a prevalence of 0.9%, most of whom are 60 years of age and older.……
文摘 Good morning, ladies and gentlemen,
In the golden autumn of Beijing, on behalf of the Organizing Committee of the Great Wall International Congress of Cardiology, and the Institute of Geriatric Cardiology at Chinese PLA General Hospital, I am very delighted to extend my warmest welcome to the representatives, colleagues and distinguished guests, both domestic and abroad, to the 5th International Forum on Geriatric Cardiology.……
文摘The advent of the Journal of Geriatric Cardiology set up jointly by Chinese and American scholars is an important event in geriatric cardiology with historical significance in China.
基金supported by the"STI2030-Major Project"of China(2023ZD04072)the National Major Agriculture Science and Technolohy Project of China(NK2022050102)+1 种基金the National Natural Science Foundation of China(32372099 and 32188102)the Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CACB-202402).
文摘Transitory starch is an important carbon source in leaves,and its biosynthesis and metabolism are closely related to grain quality and yield.The molecular mechanisms controlling leaf transitory starch biosynthesis and degradation and their effects on rice(Oryza sativa)quality and yield remain unclear.Here,we show that OsLESV and OsESV1,the rice orthologs of AtLESV and AtESV1,are associated with transitory starch biosynthesis in rice.The total starch and amylose contents in leaves and endosperms are significantly reduced,and the final grain quality and yield are compromised in oslesv and osesv1 single and oslesv esv1 double mutants.Furthermore,we found that OsLESV and OsESV1 bind to starch,and this binding depends on a highly conserved C-terminal tryptophan-rich region that acts as a starch-binding domain.Importantly,OsLESV and OsESV1 also interact with the key enzymes of starch biosynthesis,granule-bound starch synthase I(GBSSI),GBSSII,and pyruvate orthophosphote dikiase(PPDKB),to maintain their protein stability and activity.OsLESV and OsESV1 also facilitate the targeting of GBSSI and GBSSII from plastid stroma to starch granules.Overexpression of GBSSI,GBSSII,and PPDKB can partly rescue the phenotypic defects of the oslesv and osesv1 mutants.Thus,we demonstrate that OsLESV and OsESV1 play a key role in regulating the biosynthesis of both leaf transitory starch and endosperm storage starch in rice.These findings deepen our understanding of the molecular mechanisms underlying transitory starch biosynthesis in rice leaves and reveal how the transitory starch metabolism affects rice grain quality and yield,providing useful information for the genetic improvement of rice grain quality and yield.
基金Supported by the National Natural Science Foundation of China(82341034).
文摘What is already known about this topic?Mucosal IgA plays a crucial role in host immunity against respiratory viruses.Recent studies suggest that it has the potential to mitigate the transmission of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)Omicron variant.However,a comprehensive population-based analysis examining mucosal IgA levels following the winter 2022 wave of the coronavirus disease 2019(COVID-19)pandemic is yet to be conducted.What is added by this report?In our study involving 3,421 participants,we documented IgA responses subsequent to SARS-CoV-2 infection.A significant proportion of individuals sustained increased levels of IgA for over six months.These levels were also observed in individuals with prior infections who underwent asymptomatic reinfections,indicating an active production of IgA antibodies.Further,individuals with multiple vaccinations or severe symptoms tended to display elevated IgA levels after recovery.What are the implications for public health practice?IgA in the nasal mucosa is crucial for defense against SARS-CoV-2 infection.These insights can enhance our knowledge of immune responses following infection and have provided certain reference values for disease prevention and control strategies.