2,924 research outputs found
Design and Assessment of an Interactive Digital Tutorial for Undergraduate-Level Sandstone Petrology
This study describes the goals, features and effectiveness of a digital interactive tutorial which was created to provide undergraduates a 'virtual microscope' resource for learning sandstone petrology. The goal of the tutorial is to provide students exposure to the highly visual subject matter of petrography outside the confines of organized laboratory exercises. The hope is that widespread use of such digital interactive formats will allow students to gain high levels of expertise with description and interpretation of earth materials despite the reduced amounts of hands-on laboratory practice that are allowed by modern curricula. Educational levels: Graduate or professional
Nitric Oxide Bioavailability and Its Potential Relevance to the Variation in Susceptibility to the Renal and Vascular Complications in Patients With Type 2 Diabetes
OBJECTIVE—We compared the renal and systemic vascular (renovascular) response to a reduction of bioavailable nitric oxide (NO) in type 2 diabetic patients without nephropathy and of African and Caucasian heritage. RESEARCH DESIGN AND METHODS—Under euglycemic conditions, renal blood flow was determined by a constant infusion of paraminohippurate and changes in blood pressure and renal vascular resistance estimated before and after an infusion of l-Ng-monomethyl-l-arginine. RESULTS—In the African-heritage group, there was a significant fall in renal blood flow (Δ−46.0 ml/min per 1.73 m(2); P < 0.05) and rise in systolic blood pressure (Δ10.0 mmHg [95% CI 2.3–17.9]; P = 0.017), which correlated with an increase in renal vascular resistance (r(2) = 0.77; P = 0.004). CONCLUSIONS—The renal vasoconstrictive response associated with NO synthase inhibition in this study may be of relevance to the observed vulnerability to renal injury in patients of African heritage
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Stem cell marker (Nanog) and Stat-3 signaling promote MicroRNA-21 expression and chemoresistance in hyaluronan/CD44-activated head and neck squamous cell carcinoma cells.
MicroRNAs are often associated with the pathogenesis of many cancers, including head and neck squamous cell carcinoma (HNSCC). In particular, microRNA-21 (miR-21) appears to have a critical role in tumor cell survival, chemoresistance and HNSCC progression. In this study, we investigated matrix hyaluronan (HA)-induced CD44 (a primary HA receptor) interaction with the stem cell markers, Nanog and Stat-3, in HNSCC cells (HSC-3 cells). Our results indicate that HA binding to CD44 promotes Nanog-Stat-3 (also tyrosine phosphorylated Stat-3) complex formation, nuclear translocation and transcriptional activation. Further analyses reveal that miR-21 is controlled by an upstream promoter containing Stat-3 binding site(s), while chromatin immunoprecipitation assays demonstrate that stimulation of miR-21 expression by HA/CD44 signaling is Nanog/Stat-3-dependent in HNSCC cells. This process results in a decrease of a tumor suppressor protein (PDCD4), and an upregulation of i nhibitors of the apoptosis family of proteins (IAPs) as well as chemoresistance in HSC-3 cells. Treatment of HSC-3 cells with Nanog- and/or Stat-3-specific small interfering RNAs effectively blocks HA-mediated Nanog-Stat-3 signaling events, abrogates miR-21 production and increases PDCD4 expression. Subsequently, this Nanog-Stat-3 signaling inhibition causes downregulation of survival protein (IAP) expression and enhancement of chemosensitivity. To further evaluate the role of miR-21 in tumor cell-specific functions, HSC-3 cells were also transfected with a specific anti-miR-21 inhibitor in order to silence miR-21 expression and block its target functions. Our results demonstrate that anti-miR-21 inhibitor not only upregulates PDCD4 expression but also decreases IAP expression and enhances chemosensitivity in HA-treated HNSCC cells. Together, these findings indicate that the HA-induced CD44 interaction with Nanog and Stat-3 has a pivotal role in miR-21 production leading to PDCD4 reduction, IAP upregulation and chemoresistance in HNSCC cells. This novel Nanog/Stat-3 signaling pathway-specific mechanism involved in miR-21 production is significant for the formation of future intervention strategies in the treatment of HA/CD44-activated HNSCC
Moderation for professional learning
Sarah Earle, with Kendra McMahon, outlines how Teacher Assessment in Primary Science (TAPS) can support different ways of moderating
The Iowa State Student Adjustment inventory: A Filial Relations Scale for Personal Procedures
This is the third of a series of papers on the Filial Affection Inventory to be presented to the Iowa Academy of Science. Two years ago the reader (Dr. Emme) reported how the scale was constructed and how it could be used as a tool in personnel work. 1 Last year, Henry made a validation study in which he compared the scale to the home adjustment section of the Bell Adjustment Inventory. 2 The purpose of the present paper is to present the type of data which may he obtained when the inventory is administered to groups of students. Further evidence of validity was sought by studying the relation of home adjustment scores to scholastic difficulties and to maladjustment in general
Identifying Potential Security Flaws using Loophole Analysis and the SECREt
In contemporary software development thereare a number of methods that attempt to ensure the securityof a system. Many of these methods are however introducedin the latter stages of development or try to address theissues of securing a software system by envisioning possiblethreats to that system, knowledge that is usually bothsubjective and esoteric.In this paper we introduce the concept of path fixationand discuss how contradictory paths or loopholes, discoveredduring requirements engineering and using only arequirements specification document, can lead to potentialsecurity flaws in a proposed system.The SECREt is a proof-of-concept prototype tool developedto demonstrate the effectiveness of loophole analysis.We discuss how the tool performs a loophole analysisand present the results of tests conducted on an actualspecification document. We conclude that loophole analysisis an effective, objective method for the discovery ofpotential vulnerabilitites that exist in proposed systems andthat the SECREt can be successfully incorporated into therequirements engineering process
49P. Web Security: A Cross-Sectional View of Businesses Operating in Jamaica
Companies and government ministries alike have been rapidly shifting from the brick-and-mortar to the brick-and-click business model following the tremendous improvements in telecommunications infrastructure, coupled with the ever increasing competitiveness and global influences in local industries. Security unquestionably plays a pivotal role in any online presence. Websites that are built and maintained with a greater awareness of security issues have become more difficult targets for those with malicious intentions. These individuals have begun to shift their focus to softer targets both as the primary goal and as launching pads for other attacks. The aim of this paper is to highlight the susceptibility of businesses in Jamaica to these types of attacks by presenting the results of tests conducted on a representational subset of well established businesses operating in Jamaica with an online presence. We also discuss how the tests were conducted and the nature and consequences of the security flaws discovered
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Lipopolysaccharide-induced VEGF production and ambient oxidative stress in type 2 diabetes
Context
Oxidative stress is implicated in the development of microvascular disease and is associated with an upregulation of vascular endothelial growth factor (VEGF) which is pathogenetically linked to microvascular complications of diabetes. Patients of African origin have an increased susceptibility to microvascular kidney disease compared with Caucasians, the reasons and the mechanisms that contributes to this vulnerability are unclear.
Objectives
Primary) Investigate whether there are ethnic differences in Lipopolysaccharide induced monocyte VEGF production in whole blood cell cultures. Secondary) whether stimulated VEGF production is related to prevailing oxidative stress assessed by plasma lipid hydroperoxides (LOOH) and α-Tocopherol.
Design and Setting
Cross sectional study at a secondary care centre in North London, UK, serving an inner-city community of 154,000 adults.
Patients
African-Caribbean and Caucasian patients with type 2 diabetes (n=52)
Results
Lipopolysaccharide induced production of VEGF in whole blood cultures (61.8[31.9] pg/mL to 78.4[36.0] pg/mL; p<0.001) that correlated positively with LOOH levels (r=0.3, P=0.04) and was significantly higher in African-Caribbean than Caucasian type 2 diabetes patients (404 [207.5] vs 268.8 [137.0] pg/mL X109/L monocytes; P=0.018). Plasma α-Tocopherol concentration was higher in Caucasian patients (40.3[18.3] vs 30.0[9.6] µmol/L; p=0.04) compared to African-Caribbeans.
Conclusions
This study suggests that the redox environment influences VEGF production in response to proinflammatory stimuli in type 2 diabetes. The differential responsiveness by ethnic origin may be of relevance in the variations in susceptibility to the long-term microvascular complications
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