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The trend of low fertility and aging in ethnic minority areas and the policy responses in China:An analysis based on data from the latest three censuses
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作者 XU Xiao-lu PAN Ning 《Ecological Economy》 2023年第2期175-185,共11页
Low fertility and population aging are important factors affecting economic and social development.From 2000 to 2020,the development of low fertility in ethnic minority areas shows three trends of accelerated declinin... Low fertility and population aging are important factors affecting economic and social development.From 2000 to 2020,the development of low fertility in ethnic minority areas shows three trends of accelerated declining,slow declining and first falling and then rising,which are the results of the balance between the inhibiting effect of controlling birth policy and the rapidly rising birth cost,and the promoting effect of encouraging birth policy on the fertility desire of social members.The development of aging in ethnic minority areas shows two trends of acceleration and deceleration,which are the results of the balance between the promoting effect of controlling birth policy,the outflow of young and middle-aged labor force and the rise of life expectancy,and the inhibiting effect of the encouraging birth policy,the restraint of talent return and talent introduction.Combined with the development degree of low fertility and aging,we can accurately classify and implement policies for different ethnic minority areas.The areas with serious low fertility and population aging problems need economic policies to change the population age structure as soon as possible.The areas with slight low fertility and population aging problems should carry out ideological policies in priority to maintain the benign structure of population age. 展开更多
关键词 ethnic minority areas low fertility population aging
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T6态热挤压Al-5Cu-0.8Mg-0.15Zr-0.2Sc-0.5Ag合金的低周疲劳行为
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作者 王莹 陈立佳 +2 位作者 周舸 张浩宇 张思倩 《沈阳工业大学学报》 CAS 北大核心 2024年第1期77-81,共5页
为了揭示经过T6处理的热挤压Al-5Cu-0.8Mg-0.15Zr-0.2Sc-0.5Ag合金在不同温度下的低周疲劳变形与断裂行为,对T6态热挤压合金进行了室温和200℃条件下的低周疲劳实验。结果表明:在室温和200℃下合金塑性应变幅与载荷反向周次之间服从Coff... 为了揭示经过T6处理的热挤压Al-5Cu-0.8Mg-0.15Zr-0.2Sc-0.5Ag合金在不同温度下的低周疲劳变形与断裂行为,对T6态热挤压合金进行了室温和200℃条件下的低周疲劳实验。结果表明:在室温和200℃下合金塑性应变幅与载荷反向周次之间服从Coffin-Manson公式,而弹性应变幅与载荷反向周次之间服从Basquin公式;合金在室温和200℃下低周疲劳变形时,在较低外加总应变幅下疲劳变形机制主要为平面滑移,而在较高外加总应变幅下疲劳变形机制主要为波状滑移;室温和200℃下合金的疲劳裂纹均萌生于疲劳试样表面并以穿晶方式扩展。 展开更多
关键词 AL-CU-MG-ag合金 T6处理 低周疲劳 循环硬化 循环稳定 疲劳寿命 变形机制 疲劳断裂
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EFFECT OF DYNAMIC STRAIN AGING ON LOW CYCLE FATIGUE BEHAVIOUR OF 18-8 AUSTENITIC STAINLESS STEEL 被引量:2
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作者 PENG Kaiping CHEN Wenzhe OIAN Kuangwu Fuzhou University,Fuzhou,China teaching assistant,Department of Mechanical Engineering,Fuzhou University,Fuzhou 350002,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1993年第6期420-425,共6页
Studies were made of the symmetric tensile-compressive low cycle fatigue behaviour and the influence of dynamic strain aging(DSA)pre-treatment of 18-8 austenitic stainless steel. Within the testing amplitude range of ... Studies were made of the symmetric tensile-compressive low cycle fatigue behaviour and the influence of dynamic strain aging(DSA)pre-treatment of 18-8 austenitic stainless steel. Within the testing amplitude range of strain.±0.5 % to±1.5 %,the three processes of cyclic hardening,cyclic saturation and cyclic softening were observed.In the same amplitude of strain,the peak stress of the samples pre-treated by DSA is higher than that of solid-solu- tion and cold working pre-treatment,but no remarkable differences of the fatigue lives of them were found.TEM observation shows that the uniform and stable dislocation networks with high density form after DSA pre-treatment,which increases the cyclic peak stress.The cyclic softening results from the low dislocation density and elongated cell structure with low energy. 展开更多
关键词 18-8 austenitic stainless steel dynamic strain aging low cycle fatigue
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Effect of low temperature aging on microstructure and mechanical properties of super-high strength aluminum alloy 被引量:7
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作者 冯春 刘志义 +1 位作者 宁爱林 曾苏民 《Journal of Central South University of Technology》 EI 2006年第5期461-467,共7页
The effects of heat treatment on the microstructure and mechanical properties of two alloys, namely Al-12.2%Zn-2.48%Cu-2.0%Mg-0.15%Zr-0.166%Ag(alloy 1), and Al-9.99%Zn-1.72%Cu-2.5%Mg- 0.13%Zr (alloy 2) were invest... The effects of heat treatment on the microstructure and mechanical properties of two alloys, namely Al-12.2%Zn-2.48%Cu-2.0%Mg-0.15%Zr-0.166%Ag(alloy 1), and Al-9.99%Zn-1.72%Cu-2.5%Mg- 0.13%Zr (alloy 2) were investigated. The results show that low temperature aging after promotive solution treatment can increase elongation without the loss of strength for the studied alloys. The optimum aging treatment (T6) for alloy 1 and alloy 2 is 100℃/80h and 100℃/48h, respectively. Compared with other heat treatment alloys, alloy 1 and alloy 2 show super-high tensile strength up to 753MPa and 788MPa, remaining 9.3% and 9.7% elongation under T6 condition, respectively. During aging, trace addition of Ag enhances the formations of GP zone and metastable phase, and stabilizes GP zone and metastable phase to a higher temperature. Trace addition of Ag prolongs the aging time of reaching the peak strength and delays over-aging condition of the alloy. However, trace addition of Ag promotes the formation of coarse constituent in the alloy and consumes hardening alloying elements of Zn and Mg. Moreover, the addition of the transition element Zr in 7000 series super-high alloy forms incoherent Al3Zr dispersoid which can serve as nucleation sites for nonuniform precipitation of η phase during aging process. The higher the aging temperature, the greater the tendency for nonuniform precipitation of η phase. 展开更多
关键词 AL-ZN-MG-CU 低温时效 显微结构 机械性能 铝合金
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纯水相Ag^(+)/TiO_(2)溶液的制备及其抗菌性能研究
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作者 吴世斌 谢镇泽 +1 位作者 王景光 杜昶 《功能材料》 CAS CSCD 北大核心 2024年第4期4167-4173,共7页
采用低温液相法制备了纯水相纳米TiO_(2)溶液,然后在纳米TiO_(2)表面沉积Ag^(+)获得了纯水相Ag^(+)/TiO_(2)溶液。通过扫描电子显微镜(SEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、傅里叶变换红外光谱仪(FT-IR... 采用低温液相法制备了纯水相纳米TiO_(2)溶液,然后在纳米TiO_(2)表面沉积Ag^(+)获得了纯水相Ag^(+)/TiO_(2)溶液。通过扫描电子显微镜(SEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、傅里叶变换红外光谱仪(FT-IR)、紫外-可见光吸收光谱仪(UV-Vis)和荧光光谱仪(PL)进行表征。经过各项表征分析可知,Ag^(+)/TiO_(2)粒子是粒径10 nm的球形颗粒,XRD特征峰为锐钛矿二氧化钛和硫酸银的叠加峰。此外,沉积的Ag以+1的价态存在,且提高了纳米TiO_(2)的光催化活性,产生了协同效应。抗菌测试结果表明,制备的纯水相Ag^(+)/TiO_(2)溶液在不同菌种和不同应用环境下均表现优异的抗菌性能,说明了Ag^(+)/TiO_(2)抗菌的高效性和广谱性,具有极大的市场应用价值。 展开更多
关键词 ag^(+)/TiO_(2)溶液 低温液相 表面沉积 纯水相 抗菌
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Low Birth Weight in Cameroon: Research and Analysis of Factors Associated with Their Occurrence in Douala Maternity Wards
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作者 Henri Essome Merlin Boten Bounyom +17 位作者 Astrid Ndolo Kondo Ingrid Doriane Ofakem Ilick Charlotte Epossè Ekoube Rita Bono Betoko Hassanatou Iyawa Fulbert Mangala Nkwele Théophile Nana Njamen Robert Tchounzou Alphonse Ngalame Nyong Charlotte Irène Cyrielle Edjoa Mboe Moustapha Bilkissou Junie Ngaha Yaneu Marga Vanina Ngono Akam Gervais Mounchikpou Ngouhouo Grâce Tocki Toutou Michel Roger Ekono Nelly Noubi Pascal Foumane 《Open Journal of Obstetrics and Gynecology》 2024年第5期758-778,共21页
Introduction: Low birth weight (LBW) is defined by the World Health Organization (WHO) as a birth weight strictly below 2500 g, whatever the term of pregnancy. It constitutes a major public health problem, both in dev... Introduction: Low birth weight (LBW) is defined by the World Health Organization (WHO) as a birth weight strictly below 2500 g, whatever the term of pregnancy. It constitutes a major public health problem, both in developed and developing countries, due to its magnitude and its strong association with infant morbidity and mortality. Main objective was to study the factors associated with the occurrence of small-for-gestational-age newborns in Douala. Methodology: We carried out a cross-sectional analytical study with prospective data collection using a technical pretested sheet in the maternity wards of the Douala General Hospital, the Laquintinie Hospital, and the District hospitals of Deido, Nylon and Bonassama over a period of 4 months (January to April 2020). We were interested in any newborn, born alive, vaginally or by cesarean section, of low weight, seen in the first 24 hours from a full-term single-fetal pregnancy whose mother had given her consent. Our sampling was consecutive and non-exhaustive. We excluded newborns whose term was unclear and those with congenital malformations or signs of embryo-foetopathy. Data collection was done using survey sheets. Statistical analyzes were carried out with CS Pro 7.3 and SPSS version 25.0 software. The Student, Chi-square and Fischer tests were used to compare the means of the variables, the percentages with a significance threshold P value Results: During the study period, 305 full-term newborns were included, divided into 172 boys and 133 girls. The percentage of small-for-gestational-age newborns was 9.8%;after multivariate analysis by logistic regression to eliminate confounding factors, we found maternal factors associated with small for gestational age newborns;maternal age less than 20 years, primiparity, gestational age (37 - 38), a delay in prenatal visits greater than 14 weeks, anemia in pregnancy, positive toxoplasmosis serology in pregnancy, a body mass index of Conclusion: Our study revealed the potential determinants of low birth weight at term in the Cameroonian urban context and specifically in Douala. 展开更多
关键词 NEWBORN low Birth Weight Gestational age Douala
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Effect of dislocation structure evolution on low-angle grain boundary formation in 7050 aluminum alloy during aging
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作者 Wei Gu Jing-yuan Li Yi-de Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2015年第7期721-728,共8页
The effect of dislocation structure evolution on low-angle grain boundary formation in 7050 aluminum alloy during aging was studied by using optical microscopy, transmission electron microscopy, and electron backscatt... The effect of dislocation structure evolution on low-angle grain boundary formation in 7050 aluminum alloy during aging was studied by using optical microscopy, transmission electron microscopy, and electron backscatter diffraction analysis of misorientation angle distribution, cumulative misorientation and geometrically necessary dislocation (GND) density. Experimental results indicate that coarse spindle-shaped grains with the dimension of 200 μm- 80 μm separate into fine equiaxed grains of 20μm in size as a result of newborn low-angle grain boundaries formed during the aging process. More specifically, the dislocation arrays, which are rearranged and formed due to scattered dislocations during earlier quenching, transform into low-angle grain boundaries with aging time. The relative frequency of 3°-5° low-angle grain boundaries increases to over 30%. The GND density, which describes low-angle grain boundaries with the misorientation angle under 3°, tends to decrease during initial aging. The inhomogeneous distribution of GNDs is affected by grain orientation. A decrease in GND density mainly occurs from 1.83 × 10^13 to 4.40 × 10^11 m^-2 in grains with 〈111〉 fiber texture. This is consistent with a decrease of unit cumulative misorientation. Precipitation on grain boundaries and the formation of a precipitation free zone (PFZ) are facilitated due to the eroding activity of the Graft etchant. Consequently, low-angle grain boundaries could be readily viewed by optical microscopy due to an increase in their electric potential difference. 展开更多
关键词 aluminum alloys low-angle grain boundaries dislocation structure aging dislocation density
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Increased susceptibility of aging gastric mucosa to injury and delayed healing:Clinical implications 被引量:8
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作者 Andrzej S Tarnawski Amrita Ahluwalia 《World Journal of Gastroenterology》 SCIE CAS 2018年第42期4721-4727,共7页
In this editorial we comment on the article by Fukushi K et al published in the recent issue of the World Journal of Gastroenterology 2018; 24(34): 3908-3918. We focus specifically on the mechanisms of the anti-thromb... In this editorial we comment on the article by Fukushi K et al published in the recent issue of the World Journal of Gastroenterology 2018; 24(34): 3908-3918. We focus specifically on the mechanisms of the anti-thrombotic action of aspirin, gastric mucosal injury and aging-related increased susceptibility of gastric mucosa to injury. Aspirin is widely used not only for the management of acute and chronic pain and arthritis, but also importantly for the primary and secondary prevention of cardiovascular events such as myocardial infarcts and strokes. Clinical trials have consistently shown that antiplatelet therapy with long term, low dose aspirin(LDA)-75 to 325 mg daily, dramatically reduces the risk of non-fatal myocardial infarcts, stroke and mortality in patients with established arterial diseases. However, such treatment considerably increases the risk of gastrointestinal(GI) ulcerations and serious bleeding by > 2-4 fold, especially in aging individuals. This risk is further increased in patients using LDA together with other antiplatelet agents, other nonsteroidal anti-inflammatory agents(NSAIDs) and/or alcohol, or in patients with Helicobacter pylori(H. pylori) infection. Previous studies by our group and others have demonstrated prominent structural and functional abnormalities in gastric mucosa of aging individuals(which we refer to as aging gastric mucosa or "aging gastropathy") compared to the gastric mucosa of younger individuals. Aging gastric mucosa has impaired mucosal defense, increased susceptibility to injury by a variety of noxious agents such as aspirin, other NSAIDs and ethanol, and delayed and impaired healing of injury. The mechanism underlying these abnormalities of aging gastric mucosa include reduced mucosal blood flowcausing hypoxia, upregulation of PTEN, activation of proapoptotic caspase-3 and caspase-9, and reduced survivin(anti-apoptosis protein), importin-α(nuclear transport protein), vascular endothelial growth factor, and nerve growth factor. The decision regarding initiation of a long-term LDA therapy should be made after a careful consideration of both cardiovascular and GI risk factors. The latter include a previous history of GI bleeding and/or ulcers, age ≥ 70, male gender, concurrent use of other NSAIDs, alcohol consumption and H. pylori infection. Furthermore, the incidence of GI ulcers and bleeding can be reduced in patients on long term LDA treatment by several measures. Clinicians treating such patients should test for and eradicate H. pylori, instruct patients to avoid alcohol and non-aspirin NSAIDs, including cyclooxygenase-2-selective NSAIDs, and prescribe proton pump inhibitors in patients on LDA therapy. In the future, clinicians may be able to prescribe one of several potential new drugs, which include aspirin associated with phosphatidylcholine(PL2200), which retains all property of aspirin but reduces by approximately 50% LDA-induced GI ulcerations. 展开更多
关键词 aging gastric mucosa INJURY low dose aspirin PLATELETS CYCLOOXYGENASE-1 CYCLOOXYGENASE-2 THROMBOXANE A-2
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Age-related decrease in aromatase and estrogen receptor (ERα and ERβ) expression in rat testes: protective effect of low caloric diets 被引量:2
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作者 Khaled Hamden Dorothee Silandre +2 位作者 Christelle Delalande Abdefattah El Feki Serge Carreau 《Asian Journal of Andrology》 SCIE CAS CSCD 2008年第2期177-187,共11页
Aim: To examine the effects on rat aging of caloric restriction (CR1) and undernutrition (CR2) on the body and on testicular weights, on two enzymatic antioxidants (superoxide dismutase and catalase), on lipid ... Aim: To examine the effects on rat aging of caloric restriction (CR1) and undernutrition (CR2) on the body and on testicular weights, on two enzymatic antioxidants (superoxide dismutase and catalase), on lipid peroxidation and on the expression of testicular aromatase and estrogen receptors (ER). Methods: CR was initiated in 1-month-old rats and carried on until the age of 18 months. Results: In control and CR2 rats an age-related decrease of the aromatase and of ER (α and β) gene expression was observed; in parallel a diminution of testicular weights, and of the total number and motility of epididymal spermatozo was recorded. In addition, aging in control and CR2 rats was accompartied by a significant decrease in testicular superoxide dismutase, catalase activities, and an increase in lipid peroxidation level (thiobarbituric acid reactive substance), associated with alterations of spermatogenesis. Conversely, caloric restriction-treatment exerted a protective effect and all the parameters were less affected by aging. Conclusion: These results indicate that during aging, a low caloric diet (not undernutrition) is beneficial for spermatogenesis and likely improves the protection of the cells via an increase of the cellular antioxidant defense system in which aromatase/ ER could play a role. (Asian J Andro12008 Mar; 10: 177-187) 展开更多
关键词 aging low caloric diet rat testis AROMATASE estrogen receptors antioxidants
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Sn-Ag-Cu钎料的制备与显微组织性能研究
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作者 柳砚 《长春师范大学学报》 2023年第10期77-81,121,共6页
Sn-Ag-Cu系低银钎料凭借其优良的工艺和力学性能被普遍认为是最有前途的含铅钎料替代品。为了研究低银钎料的制备及其显微组织特性,制备银的质量分数分别为0、0.3%、0.5%、1.0%的四组低银钎料。比较分析熔化温度与银的质量分数对低银钎... Sn-Ag-Cu系低银钎料凭借其优良的工艺和力学性能被普遍认为是最有前途的含铅钎料替代品。为了研究低银钎料的制备及其显微组织特性,制备银的质量分数分别为0、0.3%、0.5%、1.0%的四组低银钎料。比较分析熔化温度与银的质量分数对低银钎料的熔化特性、显微组织、抗拉强度及润湿特性的影响。结果表明,添加少量的银可以降低锡铜钎料的熔化温度,使锡铜钎料的晶粒变得细小,晶粒排列得更加紧密。当钎料中银的质量分数为1.0%时,钎料的抗拉强度达到47.4 MPa,在紫铜基体上的铺展面积为39.9 mm2,润湿角为5.01°。 展开更多
关键词 Sn-ag-Cu低银钎料 显微组织 力学性能
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Ag/TiO_(2)复合物的低温合成及其光催化性能研究 被引量:1
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作者 范顶 王黎明 +2 位作者 刘峰强 徐丽慧 潘虹 《功能材料》 CAS CSCD 北大核心 2023年第4期4104-4109,共6页
以钛酸四正丁酯、硝酸银为原料,采用溶胶凝胶与溶剂热相结合的方法,在低温(120℃)条件下制备了Ag/TiO_(2)复合物。采用SEM、EDS、XRD、XPS、DRS等对样品进行表征并对其光催化性能进行测试。结果表明:所合成的Ag/TiO_(2)(3%)复合物具有... 以钛酸四正丁酯、硝酸银为原料,采用溶胶凝胶与溶剂热相结合的方法,在低温(120℃)条件下制备了Ag/TiO_(2)复合物。采用SEM、EDS、XRD、XPS、DRS等对样品进行表征并对其光催化性能进行测试。结果表明:所合成的Ag/TiO_(2)(3%)复合物具有最佳的光催化效果,光催化活性最高,在100 W高压汞灯照射下光反应90 min对30 mg/L的活性Red 24染料的降解率就能达到100%;在500 W氙灯照射下150 min对30 mg/L的活性Red 24的降解率能达到92.6%;在紫外和可见光下对染料的降解率都能达到90%以上,具有优异的紫外/可见光光催化活性。研究结果为低温合成复合光催化材料的研究提供一种有效的思路。 展开更多
关键词 ag/TiO_(2) 低温合成 光催化降解 活性染料 表征
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Ag/g-C_(3)N_(4)材料的制备及其光催化还原低浓度硝酸盐氮 被引量:1
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作者 刘志华 丘一帆 +5 位作者 岳远超 郭珊 卜湘 阳涛 黄烨 张绪霖 《环境化学》 CAS CSCD 北大核心 2023年第11期3999-4009,共11页
采用简单焙烧法及光还原沉淀法制备Ag/g-C_(3)N_(4)复合光催化材料,通过SEM、TEM、XRD、FT-IR、XPS、UV-vis等对其进行表征,并研究了该复合材料在金卤灯照射下对低浓度硝酸盐(初始质量浓度10 mg·L^(-1))的还原效果.结果表明,采用5%... 采用简单焙烧法及光还原沉淀法制备Ag/g-C_(3)N_(4)复合光催化材料,通过SEM、TEM、XRD、FT-IR、XPS、UV-vis等对其进行表征,并研究了该复合材料在金卤灯照射下对低浓度硝酸盐(初始质量浓度10 mg·L^(-1))的还原效果.结果表明,采用5%Ag/g-C_(3)N_(4)光催化剂时,硝酸盐氮去除率为58.6%,相比g-C_(3)N_(4)光催剂去除率增加21.9%;pH值为6时,硝酸盐氮还原率和产物中氮气占比最高;在180min时,硝酸盐氮去除率达66.9%,产物中氮气占比为61.6%,氮气选择性为92%.Ag可作为电子捕捉剂减缓g-C_(3)N_(4)光生电子(e^(-))与空穴(h^(+))的复合,促进硝酸盐氮的还原;同时空穴清除剂(甲酸)氧化过程中生成过氧化物自由基(COO^(·-)),也可促进硝酸盐氮的还原.经4次重复实验,硝酸盐氮去除率在65.8%以上,可见该催化剂具备良好的稳定性,具有良好的应用前景. 展开更多
关键词 ag/g-C_(3)N_(4) 低浓度硝酸盐 光催化 氮气选择性
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Maternal Age, Low Birth Weight and Early Neonatal Death in Tertiary Hospital in the Volta Region of Ghana 被引量:1
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作者 Innocent Afeke Lennox Mac-Ankrah +7 位作者 Ibrahim Jamfaru Kokou H. Amegan-Aho Hintermann Kobina Mbroh Sylvester Y. Lokpo Edem Obum Delali Geni Joseph Adu-Amankwaah Verner N. Orish 《Open Journal of Pediatrics》 2017年第4期254-262,共9页
Objectives: Current study sought to determine an association between Low Birth Weight (LBW) and early neonatal mortality at a resource limited country’s referral hospital and to determine relationship between materna... Objectives: Current study sought to determine an association between Low Birth Weight (LBW) and early neonatal mortality at a resource limited country’s referral hospital and to determine relationship between maternal age and birth outcomes. Method: A retrospective study analyzing data on births in the Volta Regional Hospital, Ghana from the period of November 2011 to June 2016. A total of 8279 births were analyzed. Results: Results suggest that teenage mothers (8.60%) are more likely to give birth to pre-term babies than the elderly (6.60%) and the adult mothers (4.61%). LBW is highest among the teenage mothers (12.69%) followed by the elderly mothers (7.87%) and then the least among the adult mothers (6.48%). Extremely Low Birth Weight (ELBW) and Macrosomia births were more observed among the elderly mothers (0.90%;2.17%) than the teenage (0.28%;0.14%) and adult mothers (0.34%;1.61%) respectively. Data suggest that 100% of the ELBW were pre-term birth, 88.28% Very Low Birth Weight (VLBW), 34.56% LBW and only 1.06% of the pre-term birth were with Normal Birth Weight (NBW). Death rate ranges from 50% for ELBW, 33.59% for VLBW, 8.22% for LBW, 5.43% for Macrosomia and 1.5% for NBW. However, death rate distribution among the various age groups was statistically not significant (P 0.106). Conclusions: Our study suggests that early neonatal death, especially deaths among ELBW and VLBW is still high at the VRH of Ghana and therefore there is the need for further studies into interventions to reduce death among neonates born with VLBW and ELBW. 展开更多
关键词 low BIRTH Weight NEONATE Early NEONATAL DEATH MATERNAL age
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Age-Related Surface Oxidases Shed into Body Fluids as Targets to Prevent Skin Aging and Reduce Cardiovascular Risk
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作者 D. James Morré Dale Kern +2 位作者 Christiaan Meadows Helen Knaggs Dorothy M. Morré 《World Journal of Cardiovascular Diseases》 2014年第3期119-129,共11页
Age-related Ecto-Nicotinamide Adenine Dinucleotide Oxidase Disulfide Thiol Exchangers 3 (ENOX3) or age-related NADH oxidases (arNOX) are expressed at the cell surface as five members of the TM-9 superfamily, initially... Age-related Ecto-Nicotinamide Adenine Dinucleotide Oxidase Disulfide Thiol Exchangers 3 (ENOX3) or age-related NADH oxidases (arNOX) are expressed at the cell surface as five members of the TM-9 superfamily, initially membrane anchored, all functionally similar, with the N-termini exposed at the cell’s exterior. ECTO-NOXes are cell surface proteins with both time-keeping CoQH2 [NAD(P)H] oxidase and protein disulfidethiol interchange activities. They are designated as ECTO-NOX proteins because of their localization on the outer surface of the plasma membrane and to distinguish them from the phox-NOXes of host defense. A ca. 30 kDa N-terminal fragment is cleaved and accumulates in body fluids (serum, saliva, urine, perspiration). arNOXes appear around age 30 and increase steadily thereafter. Reduced quinones, i.e., reduced coenzyme Q, of the plasma membrane are natural substrates. NAD(P)H is oxidized as an artificial substrate. In one phase of the arNOX cycle electrons are transferred to oxygen to generate superoxide. Substrates for the shed forms of arNOX appear to be proteins of body fluids. Circulating lipoproteins and skin matrix proteins emerge as potentially important health-related targets. Through oxidation of collagen, elastin and other proteins of the skin matrix, arNOXes are major contributors to skin aging through tyrosine and thiol oxidation and subsequent cross linking. The main destructive action of arNOX, however, may be to directly oxidize circulating lipoproteins. arNOX in the blood is structured as an integral component of the LDL particle through site-specific binding. As such, arNOXes are implicated as major risk factors for cardiovascular disease due to specific oxidation of LDLs. The superoxide produced and its conversion to hydrogen peroxide would be one part of the potentially destructive properties by contribution to lipid oxidation. Inhibition of arNOX proteins provides a rational basis for anti-aging interventions and their elimination as a major risk factor of atherogenesis. 展开更多
关键词 Atherosclerosis Cardiovascular Risk agE-RELATED NADH OXIDASE (arNOX) TM9 SUPERFAMILY of TRANSMEMBRANE Proteins Serum and Body Fluids Saliva Skin aging low Density LIPOPROTEINS
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新型NZSP陶瓷隔膜Ag/AgCl参比电极在低温钠离子熔盐中的稳定性
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作者 涂继国 常诚 +3 位作者 冯鑫 罗乙娲 孟龙 焦树强 《中国有色金属学报》 EI CAS CSCD 北大核心 2023年第12期4181-4188,共8页
开发能长期使用、电位可靠、重现性好的参比电极是熔盐电化学研究的重要基础,针对传统玻璃隔膜Ag/AgCl参比电极在低温熔盐体系中难以实现离子传导及稳定液接电位等问题,本文设计开发了以Na^(+)离子导电陶瓷Na_(3)Zr_(2)Si_(2)PO_(12)(NZ... 开发能长期使用、电位可靠、重现性好的参比电极是熔盐电化学研究的重要基础,针对传统玻璃隔膜Ag/AgCl参比电极在低温熔盐体系中难以实现离子传导及稳定液接电位等问题,本文设计开发了以Na^(+)离子导电陶瓷Na_(3)Zr_(2)Si_(2)PO_(12)(NZSP)为隔膜,适用于低温Na^(+)离子熔盐体系的新型Ag/AgCl参比电极;通过电化学测试分析,系统研究了该Ag/AgCl参比电极的稳定性和电位重现性。结果表明:NZSP隔膜能有效阻挡隔膜两端液相之间的互相扩散,Ag/AgCl参比电极的电阻低至300Ω,显示出良好的离子传导能力。多次重复使用后,Ag/AgCl参比电极的电位变化仅±5 mV,显示出优异的电极稳定性和可重复使用特性。总的来说,基于NZSP陶瓷隔膜的新型Ag/AgCl参比电极在低温Na^(+)离子熔盐体系中表现出电位稳定、响应快速及长期使用再现性好等特点。 展开更多
关键词 低温钠离子熔盐 ag/agCl参比电极 NZSP陶瓷 离子电导率 稳定性
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A creep technique for monitoring the aging precipitation in Cu-Nb bainitic steels
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作者 Xuemin Wang Bing Cao +2 位作者 Guifeng Zhou Chuang Li Xinlai He 《Journal of University of Science and Technology Beijing》 CSCD 2006年第1期50-53,共4页
A creep technique was applied on a Gleeble-1500 thermal simulator for monitoring the aging precipitation in ultra-low carbon steels containing various coppers. The aging hardening curve was obtained by the hardness te... A creep technique was applied on a Gleeble-1500 thermal simulator for monitoring the aging precipitation in ultra-low carbon steels containing various coppers. The aging hardening curve was obtained by the hardness testing. With the aid of an optical microscope and TEM, the microstructure and the aging precipitates were detected. The results indicate that when the precipitation occurs during the creep a plateau will appear on the creep curve; the left-hand and right-hand endings of the plateau correspond to the precipitation start (Ps) and finish (Pf) times, respectively. The Pf obtained from the creep curve coincides with the peak hardness time (tp) at the aging hardening curve. A precipitation-time-temperature (PTT) diagram of the steel can be obtained. 展开更多
关键词 CREEP ULCB (ultra-low carbon bainitic) steels aging PRECIPITATION
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Adsorption and Diffusion of Hydrogen Atom on Low-index Ag Planes
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作者 ZHANG Jing DIAO Zhao-Yu WANG Ze-Xin 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2005年第10期1217-1223,共7页
The 5-parameter Morse potential (5-MP) of the interaction between H atom and Ag surfaces has been constructed. The adsorption and diffusion of H on Ag low-index surfaces are investigated with 5-MP in detail. The cha... The 5-parameter Morse potential (5-MP) of the interaction between H atom and Ag surfaces has been constructed. The adsorption and diffusion of H on Ag low-index surfaces are investigated with 5-MP in detail. The characteristics of critical points are obtained. The theoretical results show that H atom can only adsorb at the three-fold site on Ag(111 ); the quasi-3-fold site and long-bridge site are stable adsorption sites on Ag(110) surface for the H atom, and at low coverage hydrogen predominantly occupies the quasi-3-fold site. This work predicts that the four-fold hollow site is the most stable adsorption state for H atom on Ag(100). The results of this work are approved by the experimental and theoretical results. 展开更多
关键词 H-ag system 5-MP ADSORPTION VIBRATION low-index surfaces
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Low-fluence photodynamic therapy combinations in the treatment of exudative age-related macular degeneration
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作者 Taylan Ozturk Hakan Oner +1 位作者 Ali Osman Saatci Suleyman Kaynak 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2012年第3期377-383,共7页
AIM:To compare the efficacy of low-fluence photodynamic therapy(PDT) combinations in the treatment of age-related macular degeneration(AMD).· METHODS:Forty-five previously untreated eyes of 45 patients with exuda... AIM:To compare the efficacy of low-fluence photodynamic therapy(PDT) combinations in the treatment of age-related macular degeneration(AMD).· METHODS:Forty-five previously untreated eyes of 45 patients with exudative AMD whose best-corrected visual acuity(BCVA) was ≥0.3(Snellen) were enrolled.15 patients in Group I underwent low-fluence PDT(25J/cm2-300mW/cm2-83sec) and intravitreal pegaptanib combination,15 patients in Group II underwent PDT(50J/cm2-600mW/cm2-83sec) and intravitreal pegaptanib combination while,15 patients in Group III underwent intravitreal pegaptanib monotherapy.Complete ophthalmologic examinations were performed in pre and post treatment visits,and the results were statistically analised.A clinical activity score(CAS) was calculated by using changes in lesion size,amount of hemorrhage,staining pattern in FA and OCT measurement of intra/subretinal fluid.≤3 logMAR lines of decrease in BCVA and decrease in CAS were considered as successful treatment.· RESULTS:The mean age of 19 female(42.2%) and 26 male(57.8%) patients was(72.82±8.02) years.Mean follow-up was(13.93±5.87) months.Lesion type was occult in 28 eyes(62.2%).Treatment success rates according to BCVA assessments were 86.7%,80%,60% and mean BCVA decrease were 0.3,1.0,2.2 logMAR lines in Group I,II and III,respectively(P >0.05).According to the changes in central macular thickness and CAS,no difference was found among the study groups(P =0.850 and P =0.811,respectively).Patients treated with combination regimens had lower intravitreal injection frequencies(P =0.015).· CONCLUSION:Combination regimen with intravitreal pegaptanib and low-fluence PDT seems to be safe and effective in stabilizing the clinical activity and BCVA in exudative AMD.· 展开更多
关键词 age-related macular degeneration photodynamic therapy low-fluence photodynamic therapy ANTI-VEGF
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(Ag,Ti)复合膜层的制备及光热性能研究
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作者 王瑶瑶 时方晓 +1 位作者 曲汝丹 覃茜语 《广州化学》 CAS 2023年第3期33-35,共3页
采用普通钠钙玻璃作为基底材料,利用磁控溅射沉积系统制备出(Ag,Ti)复合膜,通过紫外-可见光分光光度计、自制隔热木箱对膜层透光隔热性能进行分析,采用SEM对复合膜表面形貌分析,并对复合膜进行应用于室外的耐酸碱腐蚀性测试。结果表明:A... 采用普通钠钙玻璃作为基底材料,利用磁控溅射沉积系统制备出(Ag,Ti)复合膜,通过紫外-可见光分光光度计、自制隔热木箱对膜层透光隔热性能进行分析,采用SEM对复合膜表面形貌分析,并对复合膜进行应用于室外的耐酸碱腐蚀性测试。结果表明:Ag基膜层在溅射参数为Ag靶功率为75 W、溅射时间为0.2 min、氩气流量20 sccm、溅射压强2.1 Pa时具有最高的可见光透过率;(Ag,Ti)复合膜在不改变Ag溅射参数的情况下,Ti靶溅射功率为48 W、溅射时间0.2 min、氩气流量20 sccm、溅射压强2.1 Pa时具有较好的透光隔热性能,此时可见光透过率达到70%,隔热达到4.5℃,复合膜表面相对平整。 展开更多
关键词 (ag Ti)复合膜 low-E玻璃 磁控溅射 透光性能 隔热性能
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不同慢性病中老年女性骨折风险及低骨量切点预测分析 被引量:1
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作者 常凤 李彦龙 《中国组织工程研究》 CAS 北大核心 2024年第14期2140-2144,共5页
背景:中老年女性是骨质疏松的高发人群,慢性病增加骨质疏松罹患风险。低骨量是骨质疏松发病前的危险阶段,目前缺少常见慢性病人群的骨折风险差异及诊断指标切点值的相关报道。目的:通过对不同慢性病中老年女性骨折风险的分析,探讨肥胖... 背景:中老年女性是骨质疏松的高发人群,慢性病增加骨质疏松罹患风险。低骨量是骨质疏松发病前的危险阶段,目前缺少常见慢性病人群的骨折风险差异及诊断指标切点值的相关报道。目的:通过对不同慢性病中老年女性骨折风险的分析,探讨肥胖、高血压、高血脂、糖尿病、动脉硬化与骨密度的相关性,找到可预测低骨量指标的切点值,为防治骨质疏松提供参考。方法:将45-70岁203名女性受试者分为正常组和慢性病组,采用超声骨密度测量仪进行跟骨骨密度测试,采用动脉硬化仪测试肱-踝脉搏波传导速度,采用全自动生化分析仪测试血糖、血脂,采用身体成分分析仪测试体质量指数、脂肪质量及肌肉质量。结果与结论:①61-70岁女性骨密度和骨折风险系数及51-60岁、61-70岁骨强度与<50岁比较,差异有显著性意义(P<0.05);②糖尿病组骨折风险明显高于其余各组,动脉硬化组则高于正常组和肥胖组(P<0.05);③骨密度与年龄、左侧血管弹性程度、右侧血管弹性程度、三酰甘油呈负相关,与体质量指数呈正相关(P<0.05);上述指标与骨密度受试者工作特征(ROC)曲线下面积介于0.5-0.7之间,低骨量对应切点分别为55.5岁(年龄)、756.0 cm/s(左侧血管弹性)、789.0 cm/s(右侧血管弹性)、1.115 mmol/L(三酰甘油)、22.35 kg/m^(2)(体质量指数);④结论:糖尿病和动脉硬化增加中老年女性骨折风险,测定体质量指数、血管弹性和三酰甘油对女性低骨量预测具有一定早期诊断价值。 展开更多
关键词 中老年女性 骨折风险 低骨量 切点预测
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