582 research outputs found
Studies on Translocation and Distribution of Photosynthetic Assimilates in Tomato Plants I. Effects of Feeding Time and Night Temperature on the Translocation and Distribution of ^<14>C-assimilates
Barriers to success for lower-income microentrepreneurs in the San Francisco Bay Area
Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2001.Includes bibliographical references (leaves [108]-[111]).Microenterprise has recently received significant public attention and support as an economic development and poverty alleviation strategy in the United States. Considering the economic, social and professional benefits of microenterprise, self-employment will continue to be pursued by many lower-income women in the future. This study explores the role of barriers in the development and success of lower-income women's business ownership. Through a survey and in-depth interviews with clients of Women's Initiative for Self-Employment, a microenterprise program in San Francisco California, and interviews with microenterprise professionals, barriers to self-employment are identified and discussed. Barriers in question include lack of capital, training and technical assistance, lack of support from family and friends, childcare and transportation, in addition to others identified by the study sample. Special attention is given to the role of housing as a barrier to self-employment for lower-income women. Recommendations to address these barriers to lower-income entrepreneurs are presented.by Meghan Elizabeth Horl.M.C.P
An integrated approach to prognosis using protein microarrays and nonparametric methods
Over the past several years, multivariate approaches have been developed that address the problem of disease diagnosis. Here, we report an integrated approach to the problem of prognosis that uses protein microarrays to measure a focused set of molecular markers and non-parametric methods to reveal non-linear relationships among these markers, clinical variables, and patient outcome. As proof-of-concept, we applied our approach to the prediction of early mortality in patients initiating kidney dialysis. We found that molecular markers are not uniformly prognostic, but instead vary in their value depending on a combination of clinical variables. This may explain why reports in this area aiming to identify prognostic markers, without taking into account clinical variables, are either conflicting or show that markers have marginal prognostic value. Just as treatments are now being tailored to specific subsets of patients, our results show that prognosis can also benefit from a ‘personalized' approach
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Comprehensive Cell Surface Antigen Analysis Identifies Transferrin Receptor Protein-1 (CD71) as a Negative Selection Marker for Human Neuronal Cells.
Cell state-, developmental stage-, and lineage-specific combinatorial expression of cluster of differentiation (CD) molecules enables the identification of cellular subsets via multicolor flow cytometry. We describe an exhaustive characterization of neural cell types by surface antigens, exploiting human pluripotent stem cell-derived neural cell systems. Using multiwell screening approaches followed by detailed validation of expression patterns and dynamics, we exemplify a strategy for resolving cellular heterogeneity in stem cell paradigms. In addition to providing a catalog of surface antigens expressed in the neural lineage, we identified the transferrin receptor-1 (CD71) to be differentially expressed in neural stem cells and differentiated neurons. In this context, we describe a role for N-Myc proto-oncogene (MYCN) in maintaining CD71 expression in proliferating neural cells. We report that in vitro human stem cell-derived neurons lack CD71 surface expression and that the observed differential expression can be used to identify and enrich CD71- neuronal derivatives from heterogeneous cultures. Stem Cells 2019;37:1293-1306
Rhabdomyolysis recognized after elevation of liver enzymes following prolonged urologic surgery with lateral decubitus position -A case report-
The classic signs and symptoms of rhabdomyolysis are non-specific and not present in all cases, and mild cases might go unrecognized. We present a case of rhabdomyolysis recognized in a 68-year-old man after elevation of liver enzymes following prolonged urologic surgery. The patient's postoperative course was concerned with elevated serum aspartate aminotransferase and alanine aminotransferase without any clinical manifestations on the first postoperative day. After examining the serum creatine kinase and myoglobin levels, the patient was diagnosed with rhabdomyolysis. After 16 days, he was discharged with fully recovered liver enzymes and creatine kinase. We suggest that sufficient perioperative attentions should be given to patients at a higher risk of rhabdomyolysis
Reticulocyte hemoglobin equivalent (Ret He) and assessment of iron-deficient states
Direct measurement of the reticulocyte hemoglobin content provides useful information for the diagnosis and treatment of iron-deficient states. We have examined direct measurements of reticulocyte and red cell hemoglobin content on the Sysmex XE 2100 (Ret He and RBC He respectively) and the Bayer ADVIA 2120 (CHr and CH respectively) analyzers. Good agreement was found between Ret He and CHr (Y = 1.04X − 1.06; r(2) = 0.88) and between the RBC He and CH parameters (Y = 0.93X + 1; r(2) = 0.84 n = 200) in pediatric patients and in normal adults (Ret He and CHr; Y = 1.06X − 0.43; r(2) = 0.83; n = 126; RBC He and CH; Y = 0.94X + 1; r(2) = 0.87; n = 126). In 1500 blood samples from patients on chronic dialysis, Ret He was compared with traditional parameters for iron deficiency (serum iron <40 μg/dl, Tsat <20%, ferritin <100 ng/ml, hemoglobin <11 g/dl) for identifying iron-deficient states. Receiver operator characteristic (ROC) curve analysis revealed values of the area under the curve for Ret He of 0.913 (P < 0.0001). With a Ret He cutoff level of 27.2 pg, iron deficiency could be diagnosed with a sensitivity of 93.3%, and a specificity of 83.2%. Ret He is a reliable marker of cellular hemoglobin content and can be used to identify the presence of iron-deficient states
Formalizing (web) standards: an application of test and proof
Most popular technologies are based on informal or semiformal standards that lack a rigid formal semantics. Typical examples include web technologies such as the DOM or HTML, which are defined by the Web Hypertext Application Technology Working Group (WHATWG) and the World Wide Web Consortium (W3C). While there might be API specifications and test cases meant to assert the compliance of a certain implementation, the actual standard is rarely accompanied by a formal model that would lend itself for, e.g., verifying the security or safety properties of real systems. Even when such a formalization of a standard exists, two important questions arise: first, to what extend does the formal model comply to the standard and, second, to what extend does the implementation comply to the formal model and the assumptions made during the verification? In this paper, we present an approach that brings all three involved artifacts - the (semi-)formal standard, the formalization of the standard, and the implementations - closer together by combining verification, symbolic execution, and specification based testing
Associations between Sympathetic Activity, Plasma Concentrations of Renin, Aldosterone, and Parathyroid Hormone, and the Degree of Intractability of Blood Pressure Control in Hemodialysis Patients
This study was designed to examine how such factors as hemodialysis parameters, body mass index, renin and aldosterone concentrations, sympathetic nervous activity, and parathyroid hormone concentrations are associated with the control of hypertension in hemodialysis patients. Hemodialysis patients (n=114) were grouped into four categories. Group 1 had normal BP without antihypertensive medication. Group 2 needed one antihypertensive drug, Group 3 needed combination of two or three categories of antihypertensive drugs without minoxidil. Group 4 needed more than three categories of antihypertensive drugs including minoxidil. Parathyroid hormone, β2-microglobulin, renin and aldosterone, epinephrine, norepinephrine, and hemodialysis parameters were measured. The fractional clearance of urea as Kt/V urea was significantly lower in Group 3 and Group 4 than in Group 2 (p<0.01). Concentrations of parathyroid hormone were significantly higher in Group 4 than the other groups (p<0.01). Pre-hemodialysis norepinephrine concentrations were significantly higher in Group 4 than the other groups (p<0.05). Traditional factors associated with hypertension did not seem to be relevant to the degree of hypertension in hemodialysis patients in the present study. In conclusion, poor Kt/V urea, elevated parathyroid hormone concentrations, and elevated concentrations of plasma norepinephrine seemed to be the factors that might be associated with control of hypertension in hemodialysis patients
Correlates of the Severity of Coronary Atherosclerosis in Long-term Kidney Transplant Patients
Coronary artery disease remains the leading cause of early death and graft loss in renal transplant patients. The aim of this study was to identify clinical and echocardiographic parameters independently associated with the angiographically-determined severity of coronary atherosclerosis in long-term kidney transplant patients. Fifty-two kidney transplant recipients who underwent elective coronary angiography were reviewed retrospectively. Angiographic severity was evaluated using the modified Gensini index (MGI). The mean age at coronary angiography was 52.5±7.9 yr with a mean prior transplant duration of 118.1±58.8 months. Pearson correlation analysis demonstrated a positive correlation of MGI with transplant duration before coronary angiography and chronic allograft nephropathy, whereas an inverse correlation was demonstrated with ejection fraction and statin use. On subsequent multivariate linear regression analysis, transplant duration before coronary angiography, statin use, and ejection fraction were independently associated with the severity of coronary atherosclerosis in long-term kidney transplant patients. In summary, our study demonstrates that statin use, ejection fraction, and transplant duration before coronary angiography are independent parameters associated with the severity of coronary atherosclerosis in long-term kidney transplant patients. Further investigation is required to reduce the atherosclerotic burden in kidney transplant patients
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