306 research outputs found
High density Schottky barrier IRCCD sensors for SWIR applications at intermediate temperature
Monolithic 32 x 64 and 64 x 1:128 palladium silicide (Pd2Si) interline transfer infrared charge coupled devices (IRCCDs) sensitive in the 1 to 3.5 micron spectral band were developed. This silicon imager exhibits a low response nonuniformity of typically 0.2 to 1.6% rms, and was operated in the temperature range between 40 to 140 K. Spectral response measurements of test Pd2Si p-type Si devices yield quantum efficiencies of 7.9% at 1.25 microns, 5.6% at 1.65 microns 2.2% at 2.22 microns. Improvement in quantum efficiency is expected by optimizing the different structural parameters of the Pd2Si detectors. The spectral response of the Pd2Si detectors fit a modified Fowler emission model. The measured photo-electric barrier height for the Pd2Si detectors is 0.34 eV and the measured quantum efficiency coefficient, C1, is 19%/eV. The dark current level of Pd2Si Schottky barrier focal plane arrays (FPAs) is sufficiently low to enable operation at intermediate temperatures at TV frame rates. Typical dark current level measured at 120 K on the FPA is 2 nA/sq cm. The operating temperature of the Pd2Si FPA is compatible with passive cooler performance. In addition, high density Pd2Si Schottky barrier FPAs are manufactured with high yield and therefore represent an economical approach to short wavelength IR imaging. A Pd2Si Schottky barrier image sensor for push-broom multispectral imaging in the 1.25, 1.65, and 2.22 micron bands is being studied. The sensor will have two line arrays (dual band capability) of 512 detectors each, with 30 micron center-to-center detector spacing. The device will be suitable for chip-to-chip abutment, thus providing the capability to produce large, multiple chip focal planes with contiguous, in-line sensors
Oxytocin is an age-specific circulating hormone that is necessary for muscle maintenance and regeneration.
The regenerative capacity of skeletal muscle declines with age. Previous studies suggest that this process can be reversed by exposure to young circulation; however, systemic age-specific factors responsible for this phenomenon are largely unknown. Here we report that oxytocin--a hormone best known for its role in lactation, parturition and social behaviours--is required for proper muscle tissue regeneration and homeostasis, and that plasma levels of oxytocin decline with age. Inhibition of oxytocin signalling in young animals reduces muscle regeneration, whereas systemic administration of oxytocin rapidly improves muscle regeneration by enhancing aged muscle stem cell activation/proliferation through activation of the MAPK/ERK signalling pathway. We further show that the genetic lack of oxytocin does not cause a developmental defect in muscle but instead leads to premature sarcopenia. Considering that oxytocin is an FDA-approved drug, this work reveals a potential novel and safe way to combat or prevent skeletal muscle ageing
Case Report: Oral–Facial–Digital Syndrome type VI with self mutilations
We report the case of a 2.5 year old female, 2nd in order of birth of 1st cousin consanguineous marriage, with the typical features of Oral–Facial–Digital Syndrome type VI (OFDS VI) including midline pseudo cleft upper lip, sublingual nodule, molar tooth sign by MRI brain, bilateral mesoaxial polydactyly (hexadactyly), and developmental delay. The patient had self mutilations which was not reported before in OFDS VI except once.Keywords: Oral–Facial–Digital Syndrome type VI; Varadi–Papp syndrome; Self mutilation; Polydactyly; Molar tooth sign; Peudocleft li
Protonation-Induced Microphase Separation in Thin Films of a Polyelectrolyte-Hydrophilic Diblock Copolymer
Block copolymers composed of poly(oligo ethylene glycol methyl ether methacrylate) and poly(2-vinylpyridine) are disordered in the neat state but can be induced to order by protonation of the P2VP block, demonstrating a tunable and responsive method for triggering assembly in thin films. Comparison of protonation with the addition of salts shows that microphase separation is due to selective protonation of the P2VP block. Increasing acid incorporation and increasing 2-vinylpyridine content for P2VP minority copolymers both promote increasingly phase-separated morphologies, consistent with protonation increasing the effective strength of segregation between the two blocks. The self-assembled nanostructures formed after casting from acidic solutions may be tuned based on the amount and type of acid incorporation as well as the annealing treatment applied after casting, where both aqueous and polar organic solvents are shown to be effective. Therefore, POEGMA-b-P2VP is a novel ion-containing block copolymer whose morphologies can be facilely tuned during casting and processing by controlling its exposure to acid.United States. Dept. of Energy. Office of Basic Energy Sciences (Award DE-SC0001088)National Science Foundation (U.S.) (Award CMMI-1246740
Case Report: Meier-Gorlin syndrome: Report of an additional patient with congenital heart disease
We report a 7 year old female child with the classical triad of Meier-Gorlin syndrome (MGS), (microtia, absent patella and short stature). She had the characteristic facial features, with normal mentality and defective speech, skeletal abnormalities, conductive hearing loss, cystitis and normal growth hormone level. She suffered from recurrent chest infection during the first year of life which improved gradually with age. Although congenital heart is rarely observed in MGS, our patient had in addition fenestrated interatrial septal defect.Keywords Meier-Gorlin syndrome; Ear-patella-short stature syndrome; Primordial dwarfism; Microtia; Absent patell
Plasticity of the Muscle Stem Cell Microenvironment
Satellite cells (SCs) are adult muscle stem cells capable of repairing damaged and creating new muscle tissue throughout life. Their functionality is tightly controlled by a microenvironment composed of a wide variety of factors, such as numerous secreted molecules and different cell types, including blood vessels, oxygen, hormones, motor neurons, immune cells, cytokines, fibroblasts, growth factors, myofibers, myofiber metabolism, the extracellular matrix and tissue stiffness. This complex niche controls SC biology-quiescence, activation, proliferation, differentiation or renewal and return to quiescence. In this review, we attempt to give a brief overview of the most important players in the niche and their mutual interaction with SCs. We address the importance of the niche to SC behavior under physiological and pathological conditions, and finally survey the significance of an artificial niche both for basic and translational research purposes
Effect of verapamil on glycemic control in type 2 diabetic hypertensive patients in Saudi Arabia : a quasi experimental study
Background: Type 2 diabetes is a common chronic disease that continues to increase in prevalence globally and is a major healthcare burden. Diabetes and hypertension frequently occur concurrently, and the use of antihypertensive agents is common in diabetic patients. One antihypertensive agent, verapamil, has tentatively shown potentially positive effects on glycemic control in assorted pre-clinical models. Aim: To evaluate the effect of verapamil on glycemic control in hypertensive type 2 diabetic patients. Methods: Type 2 diabetic hypertensive patients were recruited from King Fahad Medical City, Riyadh, KSA, to receive oral verapamil therapy. Blood pressure and glycometabolic parameters, including fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), C-peptide, and homeostatic model assessment insulin resistance (HOMA-IR), were monitored at baseline and after 6 months of verapamil therapy. Results: Thirty-five patients (16 male, 19 female) with a mean age of 57.2 years were recruited. The use of verapamil was associated with non-significant decreases in HbA1c, FPG, C-peptide, and HOMA-IR. However, a sub-group of 17 participants showed a decrease in HbA1c that was ≥0.5%. Univariate logistic regression showed that baseline BMI, HOMA-IR, and C-peptide were significantly (P < 0.05) associated with HbA1c reductions of ≥0.5%. Conclusion: Verapamil is metabolically neutral and allows the stabilization of glycometabolic parameters in type 2 diabetic individuals. Additional research exploring the mechanism behind the variable response to verapamil therapy is warranted
Transethnic analysis of the human leukocyte antigen region for ulcerative colitis reveals not only shared but also ethnicity-specific disease associations
Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gut. Genetic association studies have identified the highly variable human leukocyte antigen (HLA) region as the strongest susceptibility locus for IBD, and specifically DRB1*01:03 as a determining factor for ulcerative colitis (UC). However, for most of the association signal such a delineation could not be made due to tight structures of linkage disequilibrium within the HLA. The aim of this study was therefore to further characterize the HLA signal using a trans-ethnic approach. We performed a comprehensive fine mapping of single HLA alleles in UC in a cohort of 9,272 individuals with African American, East Asian, Puerto Rican, Indian and Iranian descent and 40,691 previously analyzed Caucasians, additionally analyzing whole HLA haplotypes. We computationally characterized the binding of associated HLA alleles to human self-peptides and analysed the physico-chemical properties of the HLA proteins and predicted self-peptidomes. Highlighting alleles of the HLA-DRB1*15 group and their correlated HLA-DQ-DR haplotypes, we identified consistent associations across different ethnicities but also identified population-specific signals. We observed that DRB1*01:03 is mostly present in individuals of Western European descent and hardly present in non-Caucasian individuals. We found peptides predicted to bind to risk HLA alleles to be rich in positively charged amino acids such. We conclude that the HLA plays an important role for UC susceptibility across different ethnicities. This research further implicates specific features of peptides that are predicted to bind risk and protective HLA proteins
Potential Risk Factors of Developmental Cognitive Delay in the First Two Years of Life
BACKGROUND: The first two years of life constitute a critical period of rapid change. The events during this phase prepare the child for subsequent developmental competency.AIM: To determine the potential risk factors that affect an infant’s cognitive development in the first two years of life in a sample of Egyptian infantsSUBJECTS AND METHODS: A cross-sectional comparative study included 655 male and female infants. Their age ranged from 3 – 24 months. Bayley Scales of Infant and Toddler Development (Bayley III) were used for cognitive assessment. Perinatal and nutritional data were recorded. Levels of serum Zinc, Copper, Iron, vitamin B12 and complete blood count (CBC) were assessed in a subsample of 193 infants.RESULTS: Infants having below the average cognitive composite score (CCS) represented 38.47% of the whole sample. The risk of having a low average (CCS) was determined by multiple factors. Poor maternal education and low family income were the most significant social risk factors (OR = 2.19, p = 0.0003; OR = 1.64, p = 0.002 respectively). Prematurity and complicated labor represented significant perinatal risks (OR = 1.22, p = 0.005; OR = 2.39, p =0.001respectively). Bottle feeding versus breastfeeding in the first six months of life was the most significant nutritional predictor of low average (CCS) (OR = 1.79, p = 0.001). Infants with low average (CCS) had significantly lower levels of serum zinc and vitamin B12 than those with average scores. CONCLUSION: Multiple factors appear to interact affecting the early cognitive development of Egyptian infants. Prematurity, complicated labour, poor maternal education, low family income and micronutrient deficiency are the main risk factors. Studying these factors is of great value in directing governmental intervention efforts
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