社会资本影响大学生就业的两面性研究:理性选择理论的视角

根据理性选择理论,社会资本影响大学生就业的动力机制在于大学生及其家庭为了实现家庭预期利益最大化和用人单位录用决策者为了实现个人预期利益最大化而做出的理性选择。社会资本对大学生就业的影响具有两面性,积极影响在于社会资本增加大学生的就业信息来源、降低信息搜寻成本、增加就业机会、提高就业质量和满意度、促进工作流动和职业发展;消极影响在于社会资本损害就业公平、限制大学生择业范围、增加就业成本。应客观看待社会资本的两面性作用,大学生应积累社会资本,发挥社会资本的积极作用,政府应营造公平竞争的就业市场环境,减少社会资本的负面影响。

Micro/nanoelectrode-based electrochemical methodology for single cell and organelle analysis

Cells are the basic unit of life.Electrochemical analysis of single cells/organelles is essential for uncovering the molecular mechanisms of physiological and pathological processes that are difficult to elucidate on a larger scale.This paper provides an overview of the commonly used fabrication methods for micro/nanoelectrodes applied in the investigations of single cells/organelles as well as the corresponding electrochemical measurements over the last four years including extracellular measurement,combination of extra and intracellular measurement,intracellular reactive oxygen species and reactive nitrogen species(ROS/RNS)measurement,and isolated organelles measurement.

Isotopic fingerprinting of dissolved iron sources in the deep western Pacific since the late Miocene

Iron(Fe)is a productivity-limiting nutrient in the ocean.However,the sources of dissolved Fe(dFe)in the deep ocean and how they respond to tectonic and climate changes are still poorly understood.In the northern hemisphere,dust flux to the low-latitude western Pacific has increased dramatically since the late Miocene associated with intense aridification of the Asian inland.Meanwhile,the terrigenous material supply to the open ocean might have also changed as a result of the reorganization of the Pacific circulation due to the gradual closure of seaways in the low latitudes.Therefore,the western Pacific is a characteristic region for understanding the sources of dFe in the deep ocean and their responses to long term climate changes.Here,we present data on isotopic evolution of dFe and dissolved Pb since^8 Ma based on ferromanganese crust METG-03(16.0°N,152.0°E,3850 m water depth)in the western Pacific deep water.Our results show thatδ56Fe of the crust remains fairly stable since the late Miocene,i.e.,about-0.32±0.08‰(2SD).We infer thatδ56Fe of dFe in the deep western Pacific is relatively invariant at^0.45±0.1‰based on the Fe isotopic fractionation between hydrogenetic crust and the seawater dissolved component.The reconstructed isotope signature is similar to the measuredδ56Fe value(0.37±0.15‰)of the intermediate to deep waters in the modern low-latitude western Pacific region close to the island arcs,but is significantly higher than that of the eastern Pacific deep waters near South America which is controlled by the reductive dissolution of continental shelf sediments and the hydrothermal inputs(δ56Fe<-0.1‰).The deep-water 206Pb/204Pb ratio recorded by METG-03 displays systematic increase at about 8–4 Ma,reflecting increased input from sediment dissolution of low-latitude island arcs associated with reorganization of the western Pacific deep circulation.Notably,Fe isotopes of terrigenous materials from different sources are similar,while their dissolved Fe isotopic signatures released to the ocean are mainly controlled by the mechanism of particle dissolution.The stability ofδ56Fe and systematic changes in Pb isotopes over the last^8 Ma thus suggest that Asian dust dissolution and hydrothermal inputs are likely only minor sources of dFe in the low-latitude deep western Pacific,while the acquisition and transport of dFe from shelf sediments by organic ligand binding in the oxic environment is the major dFe source which keeps stable on tectonic time scales since the late Miocene.

Risk factors associated with the progression from mild keloids to severe keloids

Background:Keloids are benign fibrous growths that are caused by excessive tissue build-up.Severe keloids exert more significant effects on patients’quality of life than do mild keloids.We aimed to identify factors associated with the progression from mild keloids to severe keloids,as distinct from those associated with the formation of keloids.Methods:In this retrospective case-control study,251 patients diagnosed with keloids at West China Hospital between November 2018 and April 2021 were grouped according to the severity of lesions(mild[n=162]or severe[n=89]).We collected their basic characteristics,living habits,incomes,comorbidities,and keloid characteristics from Electronic Medical Records in the hospital and the patients’interviews.Conditional multivariable regression was performed to identify the independent risk factors for the progression of keloids.Results:Eighty-nine patients(35.5%)were classified as having severe keloids.We found the distribution of severe keloids varied with sex,age,excessive scrubbing of keloids,family income,the comorbidity of rheumatism,disease duration,characteristics of the location,location in sites of high-stretch tension,the severity and frequency of pain,the severity of pruritus,and infection.Multivariable analysis revealed significant associations between severe keloids and infection(odds ratio[OR],3.55;P=0.005),excessive scrubbing of keloids(OR,8.65;P=0.001),low or middle family income(OR,13.44;P=0.021),comorbidity of rheumatism(OR,18.97;P=0.021),multiple keloids located at multiple sites(OR,3.18;P=0.033),and disease duration>15 years(OR,2.98;P=0.046).Conclusion:Doctors should implement more active and thorough measures to minimize the progression of mild keloids in patients who have any of the following risk factors:infection,excessive scrubbing of keloids,low or middle family income,comorbidity of rheumatism,multiple keloids located at multiple sites,and disease duration>15 years.