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Characteristics of different aged plantations of Ormosia hosiei with regards to soil microbial biomass and enzymatic activities
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作者 Xiaolong Zhao Peilin Xie +5 位作者 Xueqian Zhang Zeyu Ou Haoxuan Ma Chun Suo Jingqi Ma Pan Wan 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第6期121-134,共14页
Stand age is an important indicator of tree growth and life cycle,and has implications for ecological and biological processes.This study examined changes in soil microbial biomass(SMB)as well as enzyme activities of ... Stand age is an important indicator of tree growth and life cycle,and has implications for ecological and biological processes.This study examined changes in soil microbial biomass(SMB)as well as enzyme activities of different aged plantations and revealed their relationship to soil properties.SMB,microbial biomass carbon(MBC),microbial biomass nitrogen(MBN),microbial biomass phos-phorous(MBP)and enzyme activities(β-1,4-glucosidase(β-G),β-1,4-xylosidase(β-X),cellobiohydrolase(CBH),leucine aminopeptidase(LAP),β-1,4-n-acetylglucosamine(NAG)and acid phosphatase(ACP))were measured in Oro-mosia hosiei plantations of different ages.The soil qual-ity index(SQI)model assessed soil quality.SMB contents significantly decreased in young(7-year-old)and mature plantations(45-year-old)compared to middle-aged(20-year-old)plantations.Activity of soilβ-G,β-X,CBH and NAG in the 20-year-old plantations was markedly higher than in the other plantations except forβ-G,CBH and NAG in the 45-year-old plantations.Soil organic carbon(SOC),total potassium(TK),total porosity,dissolved organic carbon,nitrate nitrogen(NO_(3)--N)and non-capillary porosity were key factors affecting SMB,while soil bulk density,pH,SOC,NO_(3)--N,TK and forest litter(FL)were the main factors affecting soil enzyme activities.SQI decreased in the order:middle-aged>mature>young.The efficiency of soil organic matter conversion,the effect of nitrogen min-eralization and fixation by microorganisms,and the better efficiency of phosphorus utilization in mid-age plantations,which improves soil physical properties,better facilitates tree growth,and further improves the buffering of the soil against acidity and alkalinity.FL quality was the only soil biological factor affecting soil enzyme activity.Our findings demonstrate that different aged plantations affect soil micro-bial biomass,enzyme activity,and soil quality. 展开更多
关键词 Plantation age Soil properties Microbial metabolism Soil health Environmental impact
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Characteristics of the HIV/AIDS Epidemic among People Aged≥50 Years in China during 2018–2021
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作者 HOU Yu Shan JIN Yi Chen +3 位作者 CAI Chang TANG Hou Lin QIN Qian Qian LYU Fan 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第4期399-405,共7页
Objective This study aimed to determine the current epidemiological status of PLWHA aged≥50 years in China from 2018 to 2021.It also aimed to recommend targeted interventions for the prevention and treatment of HIV/A... Objective This study aimed to determine the current epidemiological status of PLWHA aged≥50 years in China from 2018 to 2021.It also aimed to recommend targeted interventions for the prevention and treatment of HIV/AIDS in elderly patients.Methods Data on newly reported cases of PLWHA,aged≥50 years in China from 2018 to 2021,were collected using the CRIMS.Trend tests and spatial analyses were also conducted.Results Between 2018 and 2021,237,724 HIV/AIDS cases were reported among patients aged≥50 years in China.The main transmission route was heterosexual transmission(91.24%).Commercial heterosexual transmission(CHC)was the primary mode of transmission among males,while non-marital non-CHC([NMNCHC];60.59%)was the prevalent route in women.The proportion of patients with CHC decreased over time(Z=67.716,P<0.01),while that of patients with NMNCHC increased(Z=153.05,P<0.01).The sex ratio varied among the different modes of infection,and it peaked at 17.65 for CHC.The spatial analysis indicated spatial clustering,and the high-high clustering areas were mainly distributed in the southwestern and central-southern provinces.Conclusion In China,PLWHA,aged≥50 years,were predominantly infected through heterosexual transmission.The primary modes of infection were CHC and NMNCHC.There were variations in the sex ratio among different age groups,infected through various sexual behaviors.HIV/AIDS cases exhibited spatial clustering.Based on these results,the expansion of HIV testing,treatment,and integrated behavioral interventions in high-risk populations is recommended to enhance disease detection in key regions. 展开更多
关键词 HIV/AIDS aged≥50 years China
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Evaluation of Compatibilizers for Improving Compatibility between Waste Vegetable Oil and Aged Asphalt
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作者 WANG Yanghui DING Yongjie +3 位作者 LI Danli CAO Zhilong SUN Guoqiang MEI Zijun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第5期1278-1286,共9页
Modifying agents 2,2-Bis(4-glycidyloxyphenyl)propane(2BPE)and dibutyl phthalate(DBP)were selected to enhance the compatibility.By using molecular simulation software(Materials Studio,MS),nine systems were constructed,... Modifying agents 2,2-Bis(4-glycidyloxyphenyl)propane(2BPE)and dibutyl phthalate(DBP)were selected to enhance the compatibility.By using molecular simulation software(Materials Studio,MS),nine systems were constructed,including molecular models of aged asphalt and WVO monomers with 2BPE and/or DBP.The solubility parameters,Flory-Huggins parameters,and interaction energies of these systems were calculated to determine the impact of 2BPE and DBP on the compatibility of WVO and aged asphalt.Results showed that the addition of 2BPE and DBP reduced the difference in the solubility parameters between WVO and aged asphalt,thus improving the compatibility between WVO and aged asphalt.Additionally,using a combination of 2BPE and DBP in both aged asphalt and rejuvenator was found to be more effective than using either 2BPE or DBP alone.Finally,it was determined that evaluating the compatibility of WVO and aged asphalt using Van der Waals potential and non-bonding energy as evaluation indicators was more accurate than using electrostatic potential energy. 展开更多
关键词 road engineering aged asphalt compatibility molecular dynamics solubility parameter Flory-Huggins parameter
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Laboratory Evaluation of Performance Recovery of Aged SBS-modified Asphalt Using Regenerants with Different Base Oil Components
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作者 Li Hongzhen Li Shengbin +3 位作者 Feng Zhuangzhuang Jiang Mengmeng Li Ning Dong Fuqiang 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2024年第2期98-107,共10页
In this study,the regenerative effects of different regenerants on aged SBS-modified asphalt from different perspectives were investigated,including their conventional properties,viscoelastic behavior,creep-related pr... In this study,the regenerative effects of different regenerants on aged SBS-modified asphalt from different perspectives were investigated,including their conventional properties,viscoelastic behavior,creep-related properties,and micromorphology.Base oils composed of different proportions of aromatic and saturated hydrocarbons as well as the styrene-butadiene-styrene(SBS)restorer were used to prepare the regenerants.The results showed that the components of the base oil of the regenerant played a crucial role in determining the characteristics and performance of the recycled SBSmodified asphalt.Regenerants containing a high proportion of aromatics dissolved the hard segment in the SBS restorer,thereby delaying the effect of a reduction in the regenerants on the performance of the aged asphalts at a high temperature.Regenerants containing a high proportion of saturates dissolved the soft segment in the SBS restorer to enhance the lowtemperature performance of the recycled asphalts.In addition,the stress sensitivity of the recycled asphalts increased with the fraction of aromatics in the regenerant.As the aromatic content of the base oil components of the regenerants increased and their saturate content decreased,the state of dispersion of the SBS phase in the recycled SBS-modified asphalts improved.The optimal content of aromatics in the base oil of the regenerants should be set in the range of 33%to 47%to ensure the adequate performance of the recycled asphalts and a high efficiency of the SBS restorer. 展开更多
关键词 aged SBS-modified asphalt regeneration mechanisms base oil rheological properties MORPHOLOGY
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Microbiomics and metabolomics insights into the microbial regulation on the formation of flavor components in the traditional fermentation process of Chinese Hongqu aged vinegar
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作者 Shangong Tong Wenlong Li +7 位作者 Yuandong Rao Yanqin Xiao Yingyin Yan Weiling Guo Xucong Lü Jinyuan Sun Lianzhong Ai Li Ni 《Food Science and Human Wellness》 SCIE CAS CSCD 2024年第5期2765-2778,共14页
This study aimed to investigate microbial succession and metabolic dynamics during the traditional fermentation of Hongqu aged vinegar,and explore the core functional microbes closely related to the formation of flavo... This study aimed to investigate microbial succession and metabolic dynamics during the traditional fermentation of Hongqu aged vinegar,and explore the core functional microbes closely related to the formation of flavor components.Microbiome analysis demonstrated that Lactobacillus,Acetobacter,Bacillus,Enterobacter,Lactococcus,Leuconostoc and Weissella were the predominant bacterial genera,while Aspergillus piperis,Aspergillus oryzae,Monascus purpureus,Candida athensensis,C.xylopsoci,Penicillium ochrosalmoneum and Simplicillium aogashimaense were the predominant fungal species.Correlation analysis revealed that Acetobacter was positively correlated with the production of tetramethylpyrazine,acetoin and acetic acid,Lactococcus showed positive correlation with the production of 2-nonanone,2-heptanone,ethyl caprylate,ethyl caprate,1-hexanol,1-octanol and 1-octen-3-ol,C.xylopsoci and C.rugosa were positively associated with the production of diethyl malonate,2,3-butanediyl diacetate,acetoin,benzaldehyde and tetramethylpyrazine.Correspondingly,non-volatile metabolites were also detected through ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry.A variety of amino acids and functional dipeptides were identified during the traditional brewing of Hongqu aged vinegar.Correlation analysis revealed that Lactobacillus was significantly associated with DL-lactate,indolelactic acid,D-(+)-3-phenyllactic acid,pimelic acid,pregabalin and 3-aminobutanoic acid.This study is useful for understanding flavor formation mechanism and developing effective strategies for the suitable strains selection to improve the flavor quality of Hongqu aged vinegar. 展开更多
关键词 Hongqu aged vinegar Traditional fermentation Microbial dynamics Flavor components Bidirectional orthogonal partial least squares
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Weldability of steel used in an aged bridge
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作者 Hirohata Mikihito 《China Welding》 CAS 2024年第3期33-38,共6页
A series of experiments was performed to investigate the weldability of steel used in an aged bridge.A steel material used in an aged railway bridge constructed in 1912 was extracted for this investigation.The chemica... A series of experiments was performed to investigate the weldability of steel used in an aged bridge.A steel material used in an aged railway bridge constructed in 1912 was extracted for this investigation.The chemical compositions of this steel were suitable for welding.However,the aged steel contained much sulfur.Cruciform welded joints were fabricated with this aged steel.Welding defects or cracks were not observed in the joints.The Vickers hardness test on the welded part did not confirm extreme hardening or softening.After yielding by the static tensile test,the cruciform joints were fractured at the welded parts.One of the specimens was fractured in the middle of the thickness of the aged steel.The Sulfur contained in the aged steel might cause this type of fracture.The results show that there may be a risk of brittle fracture not only from the welded part but also from the base metal.The chemical compositions of aged steel must be analyzed when repair welding is applied to the steel. 展开更多
关键词 aged steel bridge repair welding chemical compositions weld defect brittle fracture
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Effects of phosphorus resorption on bioactive phosphorus of different-aged Pinus massoniana plantations
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作者 Xupeng Xue Xiaogai Ge +2 位作者 Lei Lei Benzhi Zhou Mai-He Li 《Forest Ecosystems》 CSCD 2024年第6期875-885,共11页
Phosphorus(P)is an important nutrient element in the photosynthesis process of plants.The effect of stand age on P nutrient dynamics in subtropical plantations is unclear.In this study,the mechanisms of above-and belo... Phosphorus(P)is an important nutrient element in the photosynthesis process of plants.The effect of stand age on P nutrient dynamics in subtropical plantations is unclear.In this study,the mechanisms of above-and belowground P cycling in subtropical P.massoniana plantations of different stand ages(5,9,19,29 and 35 years)were investigated.The percentage of metabolic P in leaves exhibited an initial rise and subsequent decline with stand age of P.massoniana throughout the growing season,culminating in a metabolic P proportion of 34%–68% in litter.During the non-growing season,the main change in the P components of P.massoniana fine roots was a transition from metabolic P to residual P.Relative to during the growing season,soil ligand P fractions decreased by 7%–22% and exchangeable P fractions increased by 0–16%in the non-growing season.Organ P components tended to decrease with increasing stand age,mainly due to the gradual decrease in soil-bioavailable P,a trend alleviated by litter input.The generation of dissolved P by soil phosphatases would limit the reduction in soilbioavailable P caused by leaf P resorption to some extent.The differences in leaf organ P components between the growing and non-growing seasons are attributed to the allocation of P by the P.massoniana.Overall,the results of this study provide a basis for exploring the mechanisms of soil bioavailable P and soil P enzymemediated organ P component allocation in P.massoniana forests.These findings will help improve the management of P-limited P.massoniana plantations to enhance their productivity. 展开更多
关键词 Organ phosphorus components Phosphorus cycling Phosphorus resorption Stand age
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Feeding Practices, Nutritional and Hemoglobin Status of Children Aged 6 to 59 Months in the Republic of Guinea: A Case Study of the Prefecture of Fria
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作者 Amadou Sylla Amadou Sadio Diallo +2 位作者 Demba Magassouba Sâa Gerard Tolno Ella Compaore 《Journal of Environmental Science and Engineering(B)》 CAS 2024年第6期238-245,共8页
Malnutrition is a major public health concern in developing countries,contributing to 45%of deaths among children under five years old.In the Republic of Guinea,the prevalence of acute malnutrition is estimated at 6.7... Malnutrition is a major public health concern in developing countries,contributing to 45%of deaths among children under five years old.In the Republic of Guinea,the prevalence of acute malnutrition is estimated at 6.7%,largely influenced by inadequate breastfeeding and complementary feeding practices.A descriptive cross-sectional study was conducted in the Prefecture of Fria to assess the impact of feeding practices on the growth and development of children aged 6 to 59 months.A sample of 450 children residing in the prefecture was included in the study.The findings revealed a prevalence of acute malnutrition of 8.9%,while 4.4%of the children were underweight,and 7.1%suffered from chronic malnutrition. 展开更多
关键词 Feeding practices Fria MALNUTRITION children aged 6 to 59 months.
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Contraception among Women Aged 35 and over at the University Hospital Center of Brazzaville
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作者 Mpia Nuelly Samantha Bialay Potokoué Gauthier Régis Jostin Buambo +4 位作者 Jean Timothée Ekani Max Lévy Emery Eouani Jules César Mokoko Clautaire Itoua Léon HervéIloki 《Open Journal of Obstetrics and Gynecology》 2024年第11期1716-1725,共10页
Objective: To study contraception among women aged 35 and over at the University Hospital of Brazzaville. Population and Methods: This was a retrospective descriptive study, conducted from April 1st 2017 to January 31... Objective: To study contraception among women aged 35 and over at the University Hospital of Brazzaville. Population and Methods: This was a retrospective descriptive study, conducted from April 1st 2017 to January 31st 2022 in the Obstetrics and Gynecology Department of the University Hospital of Brazzaville, including women aged 35 years and over who had received a contraceptive method. The study variables were sociodemographic, reproductive, clinical and contraceptive method related. Results: Two hundred and thirty customers were collected during the study period, i.e., 10.8% of the patients who received contraception. They were 38.4 ± 3 years old on average, had secondary education (46.1%), were of low socioeconomic status (54.3%), lived with a partner (98.7%) and came from an urban area (97.4%). They were multigravida (85.2%), and multiparous (63.9%) with an average of 4 living children. The indications were of two types: convenience (26.2%) and medical (73.8%). The most commonly used contraceptives were implants (72.2%) and injectable progestin (20.5%). Conclusion: The indication for contraception for women over 35 years of age at the University Hospital Center of Brazzaville is more medical, with the use of long-acting contraceptives. 展开更多
关键词 CONTRACEPTION Women aged 35 and over BRAZZAVILLE
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Risk Factors for Geo-Helminthiasis in Children Aged 6 - 36 Months in a Rural Health District in Cameroon
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作者 Isabelle Mekone Nkwele Monono Naiza +6 位作者 Gervais Talla Kamga Hugues Nana Djeunga Jeannette Epée Ngoue Patricia Epée Eboumbou Suzanne Ngo Um Sap Evelyn Mah Mungeh Joseph Kamgno 《Open Journal of Pediatrics》 2024年第2期391-400,共10页
Introduction and Objectives: Soil-Transmitted-Helminthiasis (STH) is a public health problem in Cameroon. The control strategies currently in place, particularly chemoprevention, has shortcomings linked to the target ... Introduction and Objectives: Soil-Transmitted-Helminthiasis (STH) is a public health problem in Cameroon. The control strategies currently in place, particularly chemoprevention, has shortcomings linked to the target population, which are school-age children. The objective was to determine the prevalence and the risk factors associated with geo-helminthiasis in children aged 0 to 3 years in a rural health district. Method: From December 2020 to May 2021, a descriptive and analytical cross-sectional study of 376 children between 6 and 36 months was carried out in the Akonolinga health district. This was a cluster sampling in 4 health areas. Stool samples were collected and analysed using the mini-FLOTAC method. The results expressed as the number of eggs per gram of stool. A questionnaire on socio-demographic and lifestyle data was administered to the parents. The Chi-squared test was used to measure the association between geo-helminth infection and the data collected. A multivariate analysis using logistic regression was performed (p 0.05). Results: The prevalence of STH was 19.4% (Ascaris lumbricoides: 16% and Trichuris trichiura: 8%). Risk factors were: consumption of contaminated water (AOR = 1.93 [1.03 - 3.6];p = 0.040), early contact of the child with the ground (before age of 4 months) (AOR = 4.9 [2.1 - 11.37];p .001), habit of walking barefoot (AOR = 2.91 [1.1 - 7.97];p = 0.038), and living in a habitat with unpaved ground (AOR = 7.4 [1.55 - 35.7];p = 0.012). Conclusion: The prevalence of STHs in infants was high. Preventive chemotherapy should be extended to this age-group, and other measures intensified. 展开更多
关键词 Akonolinga Soil-Transmitted-Helminths Children aged 0 - 3 Years Risk Factors
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Epidemio-Clinical Profile and Factors Associated with Performance Indicators of Integrated Management of Severe Acute Malnutrition in Children Aged 6 - 59 Months Hospitalized at the Kalaban Coro Reference Health Center
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作者 Mohamed Diarra Abdoul Salam Diarra +14 位作者 Dramane Touré Lamine Traoré Tawfiq Abu Beyadari Balilé Harber Maimouna Kanté Issa Guindo Belco Maiga Karamoko Sacko Kalirou Traoré Fatoumata Dicko Hawa Diall Bokary Diallo Salia Keita Kalba Pélieba Dianguiné Kourounté 《Open Journal of Pediatrics》 2024年第6期988-1005,共18页
Introduction: Malnutrition is an important reason for consultation in Mali’s health facilities and remains a major public health problem. The aim of this study was to describe the epidemioclinical profile and associa... Introduction: Malnutrition is an important reason for consultation in Mali’s health facilities and remains a major public health problem. The aim of this study was to describe the epidemioclinical profile and associated factors with performance indicators of integrated management of severe acute malnutrition in children aged 06 to 59 months. Methodology: this was a cross-sectional study with retrospective data collection (January 2021 to December 2022). All children hospitalized for severe acute malnutrition in the pediatric department and whose medical records were usable were included. Data collected using a standardized questionnaire was analyzed with SPSS Version 20 software. Results: A total of 534 children were included. The 12 to 23 months age group (49.1%) and the female sex (53.18%) were the most affected. Fully vaccinated children by age represented 49.4%. The predominant form of malnutrition was marasmus (77.7%). Diarrhea/vomiting (30.3%), fever (18.4%) and cough (15.5%) were the main reasons for consultations. Cure, discontinuation and death rates were 78.5%, 2.1% and 9.2%, respectively. On univariate analysis, the factors statistically associated with performance indicators (cure, drop-out, death) were gastroenteritis (P-value Conclusion: This study reveals that the frequency of severe acute malnutrition remains high at the Kalaban Coro reference health center. Better prevention of illnesses such as malaria, gastroenteritis, and respiratory infections, as well as timely referral, could help facilitate its management. 展开更多
关键词 Children aged 6 - 59 Months Severe Acute Malnutrition Associated Factors Performance Indicators
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Factors Associated with Acute Respiratory Infections in Children Aged 0 - 5 Years in the Yénawa District of Cotonou (Benin) in 2023
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作者 Virginie Mongbo Luc Béhanzin +2 位作者 Lamidhi Salami Nicolas Hamondji Amegan Edgard-Marius Ouendo 《Open Journal of Epidemiology》 2024年第2期331-342,共12页
Introduction: Acute respiratory infections remain one of the main causes of mortality in children aged 0 to 5. This work aimed to study the associated factors with the occurrence of acute respiratory infections in chi... Introduction: Acute respiratory infections remain one of the main causes of mortality in children aged 0 to 5. This work aimed to study the associated factors with the occurrence of acute respiratory infections in children 0 to 5 years old in Yénawa, Cotonou in 2023. Subjects and Method: It was an analytical cross-sectional study of children aged 0 - 5 years and their mothers in Yénawa, selected by four-degree random sampling. The sampling size, calculated using the Schwartz formula, was 126 children and 126 mothers. The dependent variable was the occurrence of acute respiratory infections. The independent variables were classified into four groups: socio-demographic and economic characteristics, behavioral factors, child-related factors, and environmental factors. Data collected by observation and questionnaire survey were analyzed using STATA version 15 software. Associated factors were investigated by bivariate analysis and multiple logistic regression, at the 5% significance level. Results: A total of 126 children aged 0 - 5 years and 126 mothers were surveyed, aged 23.5 (11 - 36) months and 30 (18 - 48) years respectively. The prevalence of acute respiratory infections was 74.60% (CI95% = 66.89 to 82.30). The associated factors were the mother’s age between 18 and 28 (OR = 10.77;CI95% = 1.89 to 61.27;p = 0.007), the use of charcoal/wood for cooking (OR = 7.36;IC = 1.99 to 27.10;p = 0.003)), children's poor personal hygiene (OR = 8.87;IC = 2.92 to 26.97;p 0.001)), and cohabitation with domestic animals (OR = 7.27;IC = 1.67 to 31.71;p = 0.015). Conclusion: Communicating with mothers about the factors identified will help reduce the prevalence of acute respiratory infections in children aged 0 to 5. 展开更多
关键词 Acute Respiratory Infections Children aged 0 - 5 Associated Factors Yénawa BENIN
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Factors Associated with Mortality in Children Aged 1 Month to 15 Years Hospitalized in the Pediatric Ward of the Kalaban-Coro Reference Health Center: Cross-Sectional Study
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作者 Abdoul Salam Diarra Mohamed Diarra +13 位作者 Dramane Touré Tawfiq Abu Beyadari Balilé Harber Maimouna Kanté Issa Guindo Belco Maiga Karamoko Sacko Kalirou Traoré Fatoumata Dicko Mamadou Togo Kalba Pélieba Mariam Sylla Mamadou Samaké Hamadoun Sangho 《Open Journal of Pediatrics》 2024年第5期800-813,共14页
Introduction: Infant and child mortality is a worldwide concern, but developing countries such as Mali are more affected. The aim of this study was to investigate morbidity and factors associated with mortality in chi... Introduction: Infant and child mortality is a worldwide concern, but developing countries such as Mali are more affected. The aim of this study was to investigate morbidity and factors associated with mortality in children aged 1 month to 15 years. Methodology: This was a cross-sectional study which took place from January 1 to December 31, 2020 covering children aged 1 month to 15 years hospitalized at the Kalaban-Coro CSRéf. Data were entered into Excel and analyzed using SPSS version 20 software. Results: Five hundred children aged 1 months to 15 years were included. The age range 1 to 5 years (53.6%) and male sex (58.2%) were the most represented. Malaria (72.2%), acute respiratory infections (6.2%) and diarrhea/dehydration (3%) were the main morbidities. Mortality was estimated at 10.6%, and the two main causes of death were malaria (56.6%) and acute respiratory infections (7.54%). Univariate analysis revealed a statistically significant association between the dependent variable (death) and age (p Conclusion: This study confirms the high rate of infant and child morbidity and mortality in our health facilities. Strengthening human resources and intensifying behavior-change communication can help reverse the trend. 展开更多
关键词 Children aged 1 Months to 15 Years MORBIDITY Factors Associated with Mortality MORBIDITY
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Dynamics of a Stochastic Epidemic Model with Age-group
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作者 LAN Xiaomin CHEN Guangmin +5 位作者 ZHOU Ruiyang ZHENG Kuicheng CAI Shaojian WEI Fengying JIN Zhen MAO Xuerong 《应用数学》 北大核心 2025年第1期294-307,共14页
A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,t... A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,the aging rates between two age groups are set to be constant.The existence-and-uniqueness of global positive solution is firstly showed.Then,by constructing several appropriate Lyapunov functions and using the high-dimensional Itô’s formula,the sufficient conditions for the stochastic extinction and stochastic persistence of the exposed individuals and the infected individuals are obtained.The stochastic extinction indicator and the stochastic persistence indicator are less-valued expressions compared with the basic reproduction number.Meanwhile,the main results of this study are modified into multi-age groups.Furthermore,by using the surveillance data for Fujian Provincial Center for Disease Control and Prevention,Fuzhou COVID-19 epidemic is chosen to carry out the numerical simulations,which show that the age group of the population plays the vital role when studying infectious diseases. 展开更多
关键词 Epidemic model age groups PERSISTENCE EXTINCTION
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The Association Between Daily Physical Activity and Risk of Hypertension in Middle-Aged and Older Adults:A Nationwide Cohort Study in China
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作者 Junhua Zhang Jie Rong +1 位作者 Hui Zhang Yongmei Yan 《Journal of Clinical and Nursing Research》 2024年第9期83-92,共10页
Physical activity (PA) plays a key role in the treatment of hypertension, and moderate to vigorous PA has been documented to lower the risk of developing hypertension. However, dose-response relationships between PA a... Physical activity (PA) plays a key role in the treatment of hypertension, and moderate to vigorous PA has been documented to lower the risk of developing hypertension. However, dose-response relationships between PA and hypertension are not consistent, and little is known about this relationship within the Chinese middle-aged and older people. We investigated the relationship between PA and hypertension within this population using China Health and Nutrition Survey 1991-2015 data. Physical activity was expressed in terms of the metabolic equivalent task (MET) and participants were divided into groups according to quartiles, namely, Q1 (< 32.97 METs-h/w), Q2 (32.97-60.38 METs-h/ w), Q3 (60.38-98.95 METs-h/w), and Q4 (> 98.95 METs-h/w). Compared with the Q1 group, the odds ratio of risk with hypertension (95% CIs) after adjusting for confounding factors were 0.63 (0.35, 1.12), 0.49 (0.28, 0.86), and 0.62 (0.35, 1.09) for those in Q2, Q3, and Q4, respectively. Restricted cubic spline functions were used and a U-shaped relationship between physical activity and hypertension risk was found, indicative of an optimal level of physical activity, which was found to be 112 METs-h/w. Our data suggest maintenance of optimal levels of total daily physical activity may be important for preventing hypertension in Chinese adults over the age of 40. 展开更多
关键词 Physical activity HYPERTENSION Middle age Older adults
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The Health and Fitness Benefits of Tai Chi for Middle-aged and Elderly People
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作者 Chunli Zhang Mattei Giovanni +1 位作者 Mattei Miriam Shuaishuai Zhai 《Journal of Clinical and Nursing Research》 2024年第12期256-261,共6页
As a traditional form of Chinese martial arts,Tai Chi attracts martial arts enthusiasts worldwide with its unique charm while also serving as an ideal fitness choice for middle-aged and elderly individuals.Its profoun... As a traditional form of Chinese martial arts,Tai Chi attracts martial arts enthusiasts worldwide with its unique charm while also serving as an ideal fitness choice for middle-aged and elderly individuals.Its profound philosophy of health preservation and remarkable fitness benefits make it particularly appealing.Tai Chi emphasizes the coordination of breathing and movement.Through slow,smooth,coherent,and gentle movements,it helps regulate the physical functions and psychological well-being of middle-aged and elderly individuals.This practice significantly enhances their overall health and effectively improves their quality of life.This paper explores the concept and characteristics of Tai Chi,examines its fitness benefits for middle-aged and elderly individuals,and proposes corresponding exercise approaches,aiming to provide practical guidance. 展开更多
关键词 Tai Chi movement Middle and old age FITNESS EFFICACY
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Association between age at diagnosis of diabetes and ocular disease:Insights from a recent article
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作者 Shi-Qi Liu Dong Wang Cheng-Chun Tang 《World Journal of Diabetes》 SCIE 2025年第1期211-216,共6页
In this article,we discuss Ye et al's recent article on the association between age at diabetes diagnosis and subsequent risk of age-related ocular diseases.The study,which utilized United Kingdom Biobank data,hig... In this article,we discuss Ye et al's recent article on the association between age at diabetes diagnosis and subsequent risk of age-related ocular diseases.The study,which utilized United Kingdom Biobank data,highlighted a strong link between early diabetes onset and major eye conditions,such as cataracts,glaucoma,agerelated macular degeneration,and vision loss,independent of glycemic control and disease duration.This finding challenges the previous belief that diabetic eye disease primarily correlates with hyperglycemia.As lifestyles evolve and the age of diabetes diagnosis decreases,understanding this relationship may reveal the complex pathogenesis underlying diabetes-related complications.This editorial summarizes potential mechanisms connecting the age of diabetes onset with four types of ocular diseases,emphasizing the significance of early diagnosis. 展开更多
关键词 DIABETES age at diagnosis CATARACT GLAUCOMA age-related macular disease Vision acuity
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Gut microbiota-astrocyte axis: new insights into age-related cognitive decline
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作者 Lan Zhang Jingge Wei +5 位作者 Xilei Liu Dai Li Xiaoqi Pang Fanglian Chen Hailong Cao Ping Lei 《Neural Regeneration Research》 SCIE CAS 2025年第4期990-1008,共19页
With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent worldwide.Aging is considered the main risk factor for cognitive decline and acts through alterati... With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent worldwide.Aging is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota,microbial metabolites,and the functions of astrocytes.The microbiota–gut–brain axis has been the focus of multiple studies and is closely associated with cognitive function.This article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative diseases.This article also summarizes the gut microbiota components that affect astrocyte function,mainly through the vagus nerve,immune responses,circadian rhythms,and microbial metabolites.Finally,this article summarizes the mechanism by which the gut microbiota–astrocyte axis plays a role in Alzheimer’s and Parkinson’s diseases.Our findings have revealed the critical role of the microbiota–astrocyte axis in age-related cognitive decline,aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition. 展开更多
关键词 age aging Alzheimer’s disease ASTROCYTES cognitive decline dementia gut microbiota gut–brain axis microbial metabolites NEUROINFLAMMATION Parkinson’s disease
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Effects of process parameters on mechanical properties and microstructures of creep aged 2124 aluminum alloy 被引量:7
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作者 湛利华 李炎光 黄明辉 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第7期2232-2238,共7页
A series of tests were carried microstructures of 2124 aluminum alloy in increase of aging time, temperature and low-to-peak-to-low manner. No significant out to investigate the effects of process parameters on mechan... A series of tests were carried microstructures of 2124 aluminum alloy in increase of aging time, temperature and low-to-peak-to-low manner. No significant out to investigate the effects of process parameters on mechanical properties and creep aging process. The results show that creep strain and creep rate increase with the applied stress. The hardness of specimen varies with aging time and stress in a effect of temperature on hardness of material is seen in the range of 185-195 ℃. The optimum mechanical properties are obtained at the conditions of (200 MPa, 185 ℃, 8 h) as the result of the coexistence of strengthening S" and S' phases in the matrix by transmission electron microscopy (TEM). TEM observation shows that applied stress promotes the formation and growth of precioitates and no obvious stress orientation effect is observed in the matrix. 展开更多
关键词 aluminum alloy creep aging behavior age hardening mechanical property MICROSTRUCTURE process parameter
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Microstructure of Mg-8Zn-4Al-1Ca aged alloy 被引量:1
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作者 董允 林小娉 +2 位作者 叶杰 郑润国 何娜 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第2期310-315,共6页
The microstructure of Mg-8Zn-4Al-1Ca aged alloy was investigated by TEM and HRTEM. The results show that the hardening produced in the Mg-8Zn-4Al-1Ca alloy is considerably higher than that in the Mg-8Zn-4A1 alloy. A d... The microstructure of Mg-8Zn-4Al-1Ca aged alloy was investigated by TEM and HRTEM. The results show that the hardening produced in the Mg-8Zn-4Al-1Ca alloy is considerably higher than that in the Mg-8Zn-4A1 alloy. A dense dispersion of disc-like Ca2Mg6Zn3 precipitates are formed in Mg-8Zn-4Al-1Ca alloy aged at 160 ℃ for 16 h. In addition, the lattice distortions, honeycomb-looking Moir&#233; fringes, edge dislocations and dislocation loop also exist in the microstructure. The precipitates of alloy aged at 160 ℃ for 48 h are coarse disc-like and fine dispersed grainy. When the alloy is subjected to aging at 160 ℃ for 227 h, the microstructure consists of numerous MgZn2 precipitates and Ca2Mg6Zn3 precipitates. All the analyses show that Ca is a particularly effective trace addition in improving the age-hardening and postponing the formation of MgZn2 precipitates in Mg-8Zn-4Al alloy aged at 160 ℃. 展开更多
关键词 Mg-8Zn-4Al-1 Ca alloy age hardening Ca2Mg6Zn3 Moire fringe
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