致辞:从“4C”到“5C”——祝贺“21世纪核心素养5C模型”发布

21世纪学习联盟(the Partnership for 21st Century Learning,以下简称为“P21”)是由世界领先的企业、大学和非政府组织等联合发起的一个机构,于2001年成立于美国华盛顿。该组织成立的初衷,是对所有学生在学校学习、职业生涯和社区生活中取得成功所需的能力、技能和知识,进行界定。21世纪的到来,使教育工作者可以有机会对学习者获得成功所需的素养进行描画。P21研发并推出了“21世纪学习框架”,其所做的工作与经济合作与发展组织(OECD)和世界经济论坛(WEF)正在进行的相关研究具有诸多共性。

Bioactive polydimethylsiloxane surface for optimal human mesenchymal stem cell sheet culture

Human mesenchymal stem cell(hMSC)sheets hold great potential in engineering three-dimensional(3D)completely biological tissues for diverse applications.Conventional cell sheet culturing methods employing thermoresponsive surfaces are cost ineffective,and rely heavily on available facilities.In this study,a cost-effective method of layer-by-layer grafting was utilized for covalently binding a homogenous collagen I layer on a commonly used polydimethylsiloxane(PDMS)substrate surface in order to improve its cell adhesion as well as the uniformity of the resulting hMSC cell sheet.Results showed that a homogenous collagen I layer was obtained via this grafting method,which improved hMSC adhesion and attachment through reliable collagen I binding sites.By utilizing this low-cost method,a uniform hMSC sheet was generated.This technology potentially allows for mass production of hMSC sheets to fulfill the demand of thick hMSC constructs for tissue engineering and biomanufacturing applications.

剖宫产后出现扩散性红斑一例

一名剖宫产术后第6天的26岁女性,因出现自剖宫产伤口至脐下腹部的扩散性红斑就诊于急诊(图1)。患者体质指数30 kg/m2,合并妊娠糖尿病,分娩时发生了胎膜早破。患者诉在过去12小时里红斑面积增加了一倍,并且4小时前出现深色瘀斑。尽管给予了常规镇痛,但患者伤口疼痛程度仍逐渐加重,疼痛评分为9/10,伴全身不适感。体温39℃,心率135次/分钟,呼吸27次/分钟。相关血液检查结果见表1。

Evaluating the sensitivity of SARS-CoV-2 infection rates on college campuses to wastewater surveillance

As college campuses reopened in fall 2020,we saw a large-scale experiment unfold on the efficacy of various strategies to contain the SARS-CoV-2 virus.Traditional individual surveillance testing via nasal swabs and/or saliva is among the measures that colleges are pursuing to reduce the spread of the virus on campus.Additionally,some colleges are testing wastewater on their campuses for signs of infection,which can provide an early warning signal for campuses to locate COVID-positive individuals.However,a representation of wastewater surveillance has not yet been incorporated into epidemiological models for college campuses,nor has the efficacy of wastewater screening been evaluated relative to traditional individual surveillance testing,within the structure of these models.Here,we implement a new model component for wastewater surveillance within an established epidemiological model for college campuses.We use a hypothetical residential university to evaluate the efficacy of wastewater surveillance for maintaining low infection rates.We find that wastewater sampling with a 1-day lag to initiate individual screening tests,plus completing the subsequent tests within a 4-day period can keep overall infections within 5%of the infection rates seen with traditional individual surveillance testing.Our results also indicate that wastewater surveillance can effectively reduce the number of false positive cases by identifying subpopulations for surveillance testing where infectious individuals are more likely to be found.Through a Monte Carlo risk analysis,we find that surveillance testing that relies solely on wastewater sampling can be fragile against scenarios with high viral reproductive numbers and high rates of infection of campus community members by outside sources.These results point to the practical importance of additional surveillance measures to limit the spread of the virus on campus and the necessity of a proactive response to the initial signs of outbreak.