461 research outputs found

    Polymers in extension:from crystallization to filament breakup

    Get PDF

    Polymers in extension:from crystallization to filament breakup

    Get PDF

    Managing Student-guided Inquiry How can we use student questions to drive instruction more frequently or with greater skill? Which methods work best in supporting a student-guided inquiry approach?

    Get PDF
    This qualitative study began with a desire to explore how science instruction can use student questions as centerpieces of ongoing, student-centered classroom inquiry. This research is supported in part by the principles of the National Research Council, National Council for the Teachers of Mathematics, and American Association for the Advancement of Science, which all purport that inquiry is an effective way to teach science. Subjects included a physical science class of eighth grade students in New York State. The students were involved in a two-week inquiry-based investigation of fossil fuels and energy, and were responsible during this time to meet the requirements of curriculum benchmarks (Appendix A.) The purpose of the study was to determine how we can use student questions to drive instruction more frequently or with more skill, and to identify methods that best support a student-guided inquiry approach. It evolved into a very different study of reflective practice. What began as a quest for information and methods evolved into a reflective journey that has already improved my practice in my classroom, increased my confidence as a teacher, and helped me to consider my future and options for personal and professional growth. When I took the time reflect, I found that my research questions were born out of a lack of confidence. I identified strategies that I currently employ that are effective in managing student-guided inquiry and that are backed by the literature, and have some keen insights into my own perceptions and my current construct of inquiry. I have concluded that the research supports my current understandings of inquiry, that my classroom was already quite student-centered. I have a much different outlook now than I did at the start of this study. It has made me much more forward-thinking and has made me less self-critical and fault-finding in my abilities as an instructor than I was at this project\u27s inception

    Retinal micro-vascular and aortic macro-vascular changes in postmenopausal women with primary hyperparathyroidism

    Get PDF
    Aim of the study was to evaluate the micro and macro-vascular changes in patients with primary hyperparathyroidism (PHPT) compared to controls. 30 postmenopausal PHPT women (15 hypertensive and 15 normotensive) and 30 normotensive controls underwent biochemical evaluation of mineral metabolism and measurements of arterial stiffness by 24 hour ambulatory blood pressure monitoring. Retinal microcirculation was imaged by a Retinal Vessel Analyzer. PHPT patients also underwent bone mineral density measurements and kidney ultrasound. PHPT patients had higher mean calcium and parathyroid hormone values compared to controls. Evaluating macro-vascular compartment, we found higher values of 24 hours-systolic, diastolic blood pressure, aortic pulse wave velocity (aPWV) and aortic augmentation index (Aix) in hypertensive PHPT, but not in normotensive PHPT compared to controls. The eye examination showed narrowing arterial and venular diameters of retinal vessels in both hypertensive and normotensive PHPT compared to controls. In hypertensive PHPT, 24 hours systolic blood pressure was associated only with parathyroid hormone (PTH) levels (beta = 0.36, p = 0.04). aPWV was associated with retinal diameter (beta = −0.69, p = 0.003), but not with PTH. Retinal artery diameter was associated with PTH (beta = −0.6, p = 0.008). In the normotensive PHPT, only PTH was associated with retinal artery diameter (beta = −0.60, p = 0.01) and aortic AIx (beta = 0.65, p = 0.02). In conclusion, we found macro-vascular impairment in PHPT and that micro-vascular impairment is negatively associated with PTH, regardless of hypertension in PHPT

    Efficacy of gluten-free diet in patients with rheumatoid arthritis.

    Get PDF
    Recent research has increasingly shown that depending on the foods we eat, gut flora may be affected by an inflammatory or anti-inflammatory response, thus playing an important role in inflammatory autoimmune diseases, such as rheumatoid arthritis or gastroenterological disorders. Gluten seems to be a glycoprotein with a clinically relevant inflammatory effect. Several observational studies and anecdotal cases reported a correlation between gluten and various diseases, including autoimmune diseases, such as rheumatoid arthritis. This study aimed to evaluate whether gluten-free diet could be effective in controlling inflammation and ongoing rheumatoid arthritis symptoms. We report 4 cases of patients with long-standing rheumatoid arthritis with no response to several conventional and biotechnological drugs, treated with a gluten-free diet concurrently with the drug therapy. Our patients presented different degrees of response to the diet, in terms of disease remission and improvement of symptoms. Our cases confirm that a gluten-free diet may improve symptoms of rheumatoid arthritis, even in patients resistant to conventional drug therapies

    Osteomalacia and Vitamin D Status: A Clinical Update 2020

    Get PDF
    Historically, rickets and osteomalacia have been synonymous with vitamin D deficiency dating back to the 17th century. The term osteomalacia, which literally means soft bone, was traditionally applied to characteristic radiologically or histologically documented skeletal disease and not just to clinical or biochemical abnormalities. Osteomalacia results from impaired mineralization of bone that can manifest in several types, which differ from one another by the relationships of osteoid (ie, unmineralized bone matrix) thickness both with osteoid surface and mineral apposition rate. Osteomalacia related to vitamin D deficiency evolves in three stages. The initial stage is characterized by normal serum levels of calcium and phosphate and elevated alkaline phosphatase, PTH, and 1,25-dihydroxyvitamin D [1,25(OH)2D]—the latter a consequence of increased PTH. In the second stage, serum calcium and often phosphate levels usually decline, and both serum PTH and alkaline phosphatase values increase further. However, serum 1,25(OH)2D returns to normal or low values depending on the concentration of its substrate, 25-hydroxyvitamin D (25OHD; the best available index of vitamin D nutrition) and the degree of PTH elevation. In the final stage, hypocalcemia and hypophosphatemia are invariably low with further exacerbation of secondary hyperparathyroidism. The exact,or even an approximate, prevalence of osteomalacia caused by vitamin D deficiency is difficult to estimate, most likely it is underrecognized or misdiagnosed as osteoporosis. Signs and symptoms include diffuse bone, muscle weakness, and characteristic fracture pattern, often referred to as pseudofractures, involving ribs, scapulae, pubic rami, proximal femurs, and codfish-type vertebrae. The goal of therapy of vitamin D-deficiency osteomalacia is to alleviate symptoms, promote fracture healing, restore bone strength, and improve quality of life while correcting biochemical abnormalities. There is a need for better understanding of the epidemiology of osteomalacia. Simplified tools validated by concurrent bone histology should be developed to help clinicians promptly diagnose osteomalacia

    Psoriatic spondyloarthritis and Sjögren syndrome: a casual association?

    Get PDF
    The association between Sjögren syndrome (SS) and psoriatic arthritis (PsA) is rare. Herein, we report a case of SS in a PsA patient with the mutilans variant. A 67-year old woman developed PsA with progressive articular destruction up to the typical deformation of 'telescoping fingers' in the distal phalanges. Psoriatic onychopathy presented ten years after the osteolytic damage in the hands. This late appearance led to delayed diagnosis and therapy, and, consequently, worsened the articular destruction. Thereafter, the patient developed a typical SS with clinical symptoms, such as xerophthalmia and xerostomia. This diagnosis was confirmed by positive diagnostic tests, such as Schirmer test, ANA, and anti-SSA/Ro and anti-SSB/La antibodies. A potential association between the two diseases is discussed

    Vitamin D and Its Relationship with Obesity and Muscle

    Get PDF
    The skin synthesis of vitamin D represents the first step of a metabolic pathway whose features have been extensively studied and clarified in the last decades. In particular, the production of active and inactive forms of the hormone and the actions of the corresponding enzymes have offered new insights into the knowledge of vitamin D metabolism. Additionally, the description of the different organs and tissues expressing the vitamin D receptor and its possible functions, as well as its genetic determinants, have allowed focusing on the interrelationship between vitamin D and many physiological and pathological functions. In this context, many studies reported the association between vitamin D and adipose tissue metabolism, as well as the possible role of the hormone in obesity, weight, and fat mass distribution. Finally, many reports focused on the vitamin D-related effects on skeletal muscle, particularly on the mechanisms by which vitamin D could directly affect muscle mass and strength. This paper is mainly aimed to review vitamin D metabolism and its relationship with obesity and skeletal muscle function

    Identification of Plant Extracts that Inhibit the Formation of Diabetes-Linked IAPP Amyloid

    Get PDF
    The extracts of 27 vegetables, spices and herbs were screened for their functional ability to inhibit the aggregation of islet amyloid polypeptide (IAPP, amylin) into toxic amyloid aggregates. The aggregation of IAPP has been directly linked to the death of pancreatic β-islet cells in type 2 diabetes. Inhibiting the aggregation of IAPP is believed to have the potential to slow, if not prevent entirely, the progression of this disease. As vegetables, spices and herbs are known to possess many different positive health effects, the extracts of 27 plants (abundant within the United States and spanning several plant families) were screened for their ability to inhibit the formation of toxic IAPP aggregates. Their anti-amyloid activities were assessed through (1) thioflavin T binding assays, (2) visualization of amyloid fibers using atomic force microscopy and (3) cell rescue studies. From this research, mint, peppermint, red bell pepper and thyme emerged as possessing the greatest anti-amyloid activity
    • …
    corecore