Role of Plasma MMP 9 levels in the Pathogenesis of Chronic Pancreatitis

Pancreatic fibrosis is a key pathological feature in the etiology of chronic pancreatitis that leads to obliteration of exocrine and endocrine pancreatic tissues and its replacement by fibrous tissue resulting in clinical manifestations. Matrix metalloproteinase 9 is a member of the MMP family that is also known as gelatinase B, degrades type IV collagen of extracellular matrix and basal membrane. The present study is aimed at evaluating the clinical significance of plasma concentration of MMP-9 in chronic pancreatitis. The samples were obtained from 112 chronic pancreatitis patients and an equal number of age and sex matched healthy controls. MMP-9 levels were quantitatively measured by ELISA assay. Statistical analysis was applied to test the significance of results. The present study revealed a significant increase of plasma MMP 9 levels in chronic pancreatitis patients compared to control subjects. Elevated levels were also observed in all the patient groups compared to control subjects with regard to sex, age, addictions etc. MMP-9 degrades the type IV collagens in normal basement membrane, which in turn activates the pancreatic stellate cells which promote the development of pancreatitic fibrosis. Thus, elevated plasma levels of MMP-9 may act as a susceptibility factor for the development of chronic pancreatitis.     

Journal clustering using a bibliographic coupling method

The classification of journal titles into fields or specialties is a problem of practical importance in library and information science. An algorithm is described which accomplishes such a classification using the single-link clustering technique and a novel application of the method of bibliographic coupling. The novelty consists in the use of two-step bibliographic coupling linkages, rather than the usual one-step linkages. This modification of the similarity measure leads to a marked improvement in the performance of single-link clustering in the formation of field or specialty clusters of journals. Results of an experiment using this algorithm are reported which grouped 890 journals into 168 clusters. This scope is an improvement of nearly an order of magnitude over previous journal clustering experiments. The results are evaluated by comparison with an independently derived manual classification of the same journal set. The generally good agreement indicates that this method of journal clustering will have significant practical utility for journal classification.     

全光波长变换器及其在光网络中的应用

All optical network (AON) is a hot topic in recentstudies of optical fiber communications . Key tech-niques in AONinclude optical switching/routing,opti-cal cross connection ( OXC) , all optical wavelengthconversion (AOWC) ,all optical buffering,etc. Opti…     

全球气候变化问题的视点:中国和美国

就中国在国际气候变化协议中的位置、中国怎样减少CO2排放、有关碳交易的制度建设、中国在国际碳交易市场中扮演的角色和气候变化协定中的重要性进行了探讨,介绍了美国正在运行的气候法案的主要内容,并提出了中国目前的气候政策和碳交易市场发展中存在的问题,在国际气候大环境中和美国进行了分析对比。     

“Things your history teacher won't teach you: Science edition”: Black women science teachers as anti-racist teachers

Marginalized communities cannot and do not have decontextualized experiences with how socioscientific issues, such as exposure to COVID-19 as frontline essential workers, high Black infant mortality rates, air pollution leading to respiratory problems, and other issues, affect their communities. As PreK-12 science teachers and teacher educators strive to dismantle oppressive practices in their classrooms and curriculum, it would be helpful to learn from Black women science teachers who have been engaging in anti-racist practices before the racial awakenings of Summer 2020. In this study, three different virtual focus groups, or Sista Circles, were conducted with 18 Black women secondary science teachers. Ranging from 1 to 22 years of experience, Black women teachers across the country and international participants in Canada and Qatar participated in the Sista Circles. From intersectional qualitative analysis and narrative inquiry, the findings of the study reveal that Black women science teachers enact anti-racist science teaching by bringing something new to the community; using NGSS standards within the context of the community; teaching at the intersection of history, culture, and science learning and teaching; and building critical consciousness in the science classroom. Furthermore, the findings of the study have implications for the use of anti-racist frameworks within the context of science education that were authentically the practices of the Black women in the study. This study offers insights into how the critical consciousness of Black women teachers can be represented in the science classroom even in times of nonsupport from peers and administration. The power and necessity of Black women teachers are paramount in science classrooms specifically because of the neutral, apolitical ways science teaching has been approached in the past. The narratives and stories shared here exemplify how Black women science teachers transform science teaching and learning by displaying various acts of Criticality.     

Intentional Informationists: Re-envisioning Information Literacy and Re-designing Instructional Programs Around Faculty Librarians' Strengths as Campus Connectors,Information Professionals,and Course Designers

This article adds to the recent literature that questions, and hopes to redefine, the information literacy notions and practices in academic libraries and their institutions. The authors draw on research in the area of social justice to express the need for academic libraries to explore new avenues to insure their institution's graduates are not merely competent consumers of information. The authors put forward the notion of the intentional informationist, who they define as having the contextual, reflective and informational skills to identify information opportunities, tackle complex information problems and pitfalls, and provide solutions or considerations that do not just meet her individual needs. In addition, they pose questions and detail opportunities, partnerships, and examples of curricular and co-curricular integration to engage students beyond the library, instruction sessions, a single course, or graduation requirement.     

The effect of acceleration signal processing for head impact numeric simulations

Brain injury research in sport employs a variety of physical models equipped with accelerometers. These acceleration signals are commonly processed using filters. The purpose of this research was to determine the effect of applying filters with different cutoff frequencies to the acceleration signals used as input for finite element modeling of the brain. Signals were generated from reconstructions of concussion events from American football and ice hockey in the laboratory using a Hybrid III headform. The resulting acceleration signals were used as input for the University College Dublin Brain Trauma Model after being processed with filters. The results indicated that using a filter with a cutoff of 300 Hz or higher had little effect on the resulting strain measures. In some cases there was some effect of the filters on the peak linear (8–30g) and rotational measures (1000–4000 rad/s²), but little effect on the finite element strain result (approximately 2–6 %). The short duration and high magnitude accelerations, such as the puck impact, were most affected by the cutoff frequency of different filters.     

Sequences of reward magnitude and runway performance

Three groups of rats underwent 24 days of training and 12 days of extinction (three trials per day) in a runway under conditions of increasing (I), decreasing (D), and random (R) sequences of reward magnitudes (0, 45, and 500 mg). The I Ss ran faster over the daily trials, the D Ss slowed down, and the R Ss ran at approximately equal speeds on each trial. The patterned running observed in training persisted in extinction, with the R Ss running fastest and the I Ss next. The results were discussed in terms of Capaldi’s sequential theory and Amsel’s frustration theory.