Culture of cells as three-dimensional (3D) aggregates, named spheroids, possesses great potential to improve in vitro cell models for basic biomedical research. However, such cell spheroid models are often complicated, cumbersome, and expensive compared to conventional Petri-dish cell cultures. In this work, we developed a simple microfluidic device for cell spheroid formation, culture, and harvesting. Using this device, cells could form uniformly sized spheroids due to strong cell–cell interactions and the spatial confinement of microfluidic culture chambers. We demonstrated cell spheroid formation and culture in the designed devices using embryonic stem cells, carcinoma cells, and fibroblasts. We further scaled up the device capable of simultaneously forming and culturing 5000 spheroids in a single chip. Finally, we demonstrated harvesting of the cultured spheroids from the device with a simple setup. The harvested spheroids possess great integrity, and the cells can be exploited for further flow cytometry assays due to the ample cell numbers. 相似文献
Education and Information Technologies - As a technology the effect of the Internet of Things (IoT) is so strong that it has changed the way of living. The transition is also apparent in the field... 相似文献
Purpose: The purpose of this study is to develop a conceptual framework with related analysis methodologies that identifies the influence of social environment on an established cropping system.
Design/methodology/approach: A stratified survey including 103 villages and 823 farmers was conducted in all districts of Haryana (India). Firstly, technical efficiency (TE) was modeled using biophysical data including grain yield, seeding rate, wheat varieties, tillage, sowing date, seed source, harvesting method and the application of fertilizer, herbicide and irrigation. The relationship between TE and social community factors such as farm size, farmer age, level of education and agricultural support programs was analyzed by regression tree.
Findings: TE was lower with the farmers who only have education to a primary standard. Farmers with high TE scores were mostly between 35 and 40 years of age, and a higher TE association was common for farmers who use technical publications. Social individual factors such as farmers’ views on the future of farming were also analyzed across different TE levels.
Practical implications: Farmers with lower TE are an obvious target for production improvement, particularly given the understanding that the overall production yield gap is small in Haryana.
Theoretical implications: Our conceptual framework shows a quantitative way to establish the socio-ecological linkage, and to identify the opportunities for changes in management with extension services leading to productivity improvement.
Originality/value: This paper provides a novel framework with detailed methodology to effectively identify the socio-economic factors that limit the biophysical production in an agricultural system. 相似文献
The objectives of this paper were to explore the existing status of agricultural higher education in India, application of marketing concepts in similar institutions and to find the most appropriate marketing concept to make agricultural higher education more competitive. Extensive searches of relevant agricultural education, business management and higher educational data bases were made. It was found that agricultural higher education in India is stagnant and is facing an identity crisis among its stakeholders. Marketing theories and concepts which are now being applied in higher education across the globe have not been thought of in the context of agriculture education. A review of the literature suggested that considering the objectives, the multiplicity of stakeholders and the nature of public-funded agricultural education, marketing orientation would be most appropriate. Based on the experiences of similar institutions, the paper suggests a three-level strategy for the implementation of marketing orientation in institutions of agricultural higher education. 相似文献
This paper examines stability and change during the elementary-to-middle school transition, focusing on adolescents’ experiences of home–school dissonance because of real or perceived differences between home/self and values within the school context. Relationships were hypothesized between exacerbation and amelioration of dissonance, middle school mastery and performance goal practices, and students’ perceptions thereof. The sample consisted of 274 African-American and 284 European-American (49% female) students. Middle school teachers (N = 236) provided data on school academic practices. Multilevel growth curve analysis indicated significant variance among the 10 middle schools regarding change in dissonance. Both mastery-focused middle school practices and students’ perception of middle school classrooms as more performance and less mastery focused than elementary classrooms were significant predictors of change in dissonance. Path-analyses evidence pointed to the mediational role of school belonging on the relationship between perception of classroom mastery goals and dissonance. Path analyses revealed direct and indirect effects of perception of classroom performance goals on dissonance and school belonging. This paper highlights the importance of creating inclusive learning environments that minimize social comparison saliency and validate students for who they are. 相似文献
Molecular combing and flow-induced stretching are the most commonly used methods to immobilize and stretch DNA molecules. While both approaches require functionalization steps for the substrate surface and the molecules, conventionally the former does not take advantage of, as the latter, the versatility of microfluidics regarding robustness, buffer exchange capability, and molecule manipulation using external forces for single molecule studies. Here, we demonstrate a simple one-step combing process involving only low-pressure oxygen (O2) plasma modified polysilsesquioxane (PSQ) polymer layer to facilitate both room temperature microfluidic device bonding and immobilization of stretched single DNA molecules without molecular functionalization step. Atomic force microscopy and Kelvin probe force microscopy experiments revealed a significant increase in surface roughness and surface potential on low-pressure O2 plasma treated PSQ, in contrast to that with high-pressure O2 plasma treatment, which are proposed to be responsible for enabling effective DNA immobilization. We further demonstrate the use of our platform to observe DNA-RNA polymerase complexes and cancer drug cisplatin induced DNA condensation using wide-field fluorescence imaging. 相似文献
There is an extensive amount of Library and Information Science (LIS) writing produced each year. While there is general awareness regarding the variety of journal literature, there is no certainty on the percentage of the collection that we can call research. This project is an important first step in answering the question. A content analysis of the LIS academic/scholarly journals at the Simmons College Library was conducted. The research level collection of LIS literature makes the library an ideal candidate for this study. The latest issue of each journal subscribed to for fiscal year 2012–2013 containing academic/scholarly content was analyzed. Each article was analyzed to determine: 1) if it was research or non-research, 2) the method used to collect data for the study in the article, and 3) the subject terms or keywords associated with the article. 105 journal titles were identified out of 177 periodicals. In the 1880 articles analyzed from these, 16% qualified as research. Surveys were found to be the most popular research method used. This study will benefit students, faculty, and staff with research requirements as well as librarians who guide patrons through a search for research literature. 相似文献
This study investigates the decay and half-life of online citations cited in four open access journals published between 2000 and 2009. A total of 1158 online citations cited in 1086 research articles published in two science and social science journals spanning a period of 10 years (2000–2009) were extracted. Study found that 24.58% (267 out of 1086) of articles had online citations and these articles contained a substantially very less number of online citations (2.98%) compared to previous study results. 30.56% (26% in Science and 52.73% in Social Science) of online citations were not accessible and remaining 69.44% of online citations were still accessible. The ‘HTTP 404 error message-page not found’ was the overwhelming message encountered and represented 67.79% of all HTTP message. Domains associated with .ac and .net had higher successful access rates while .org and .com/.co had lowest successful access rates. The half-life of online citations was computed to be approximately 11.5 years and 9.07 years in Science and Social science journal articles respectively. 相似文献
IntroductionDetecting low viral load has been a challenge in this pandemic, which has led to its escalated transmission. Complement activation has been implicated in pathogenesis of Covid-19 infection. Thus, evaluation of complement activation in suspected Covid-19 infection may help to detect infection and limit false negative cases thus limiting transmission of infection. We speculate that measuring C4b, produced from an activated complement system due to the presence of Covid-19 may help in its detection, even when the viral titers are low.MethodsPlasma C4b levels of symptomatic RT-PCR positive patients (cases, n = 40); symptomatic RT-PCR negative patients (n = 35) and asymptomatic RT-PCR negative controls (n = 40) were evaluated. Plasma C5b-9, IL-6, D-dimer and C1-Inhibitor (C1-INH) were also measured in cases and controls. ELISA kits were used for all measurements. Statistical analyses were carried out using Stata, version 12 (Stata Corp., Texas, USA).ResultsC4b levels were found to be significantly increased in RT-PCR positive patients as compared to asymptomatic RT-PCR negative controls. RT-PCR negative but symptomatic patients still showed increased C4b levels. The significantly higher levels of C4b in cases with a cut-off value of ≥ 116 ng/ml with optimum sensitivity and specificity of 80% and 52% respectively is indicative of its possible use as an adjunct marker. Increased levels of D-dimer, IL6, along with decreased levels of C1-INH were found in cases compared to controls. Whereas, C5b-9 levels were not significantly raised in cases.ConclusionsThe results of our study suggests that plasma C4b may help to detect infection in false negative cases of RT-PCR that escape detection owing to low viral load. However, to confirm it a large-scale study is needed.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12291-022-01033-z. 相似文献