3,923 research outputs found
A Method to Guarantee Local Convergence for Sequential Quadratic Programming with Poor Hessian Approximation
Sequential Quadratic Programming (SQP) is a powerful class of algorithms for
solving nonlinear optimization problems. Local convergence of SQP algorithms is
guaranteed when the Hessian approximation used in each Quadratic Programming
subproblem is close to the true Hessian. However, a good Hessian approximation
can be expensive to compute. Low cost Hessian approximations only guarantee
local convergence under some assumptions, which are not always satisfied in
practice. To address this problem, this paper proposes a simple method to
guarantee local convergence for SQP with poor Hessian approximation. The
effectiveness of the proposed algorithm is demonstrated in a numerical example
Modulation of macrophage and microglial responses to axonal injury in the peripheral and central nervous systems
Journal ArticleOBJECTIVE: After axonal injury, macrophages rapidly infiltrate and become activated in the mammalian peripheral nervous system (PNS) but not the central nervous system (CNS). We used the dorsal root pathway to study factors that modulate the response of macrophages to degenerating axons in both the PNS and the CNS. METHODS: Lewis rats underwent transection of dorsal roots (Group I), stab within the spinal cord (Group II), crush at the dorsal root entry zone (Group III), transection of dorsal roots combined with a CNS lesion (Group IV), or systemic administration of a known activator of macrophages, lipopolysaccharide, alone (Group V) or combined with transection of dorsal roots (Group VI). ED-1 antibody stained for macrophages and activated microglia at 7, 14, and 42 days postinjury. RESULTS: At early time points, Group I demonstrated ED-1 cells in the PNS but not the CNS portion of the degenerating dorsal roots. Group II revealed ED-1 cells near the stab lesion. Group III demonstrated ED-1 cells adjacent to the dorsal root entry zone crush site. Group IV revealed ED-1 cells along both the PNS and the CNS portions of the degenerating dorsal roots when the CNS lesion was placed near the transected roots. Group V demonstrated few ED-1 cells in the PNS and the CNS, whereas Group VI revealed a marked ED-1 cellular response along both the PNS and the CNS portions of the transected dorsal roots. CONCLUSION: Local CNS trauma and systemic administration of lipopolysaccharide can "prime" macrophages/microglia, resulting in an enhanced response to degenerating axons in the CNS. Such priming might prove useful in promoting axonal regeneration
A novel phospholipid-binding protein from the yeast Saccharomyces cerevisiae with dual binding specificities for the transport GTPase Ypt7p and the Sec 1-related Vps33p
The gene product of the Saccharomyces cerevisiae open reading frame YDR229w (named IVY1 for: Interacting with Vps33p and Ypt7p) was found to interact with both the GTPase Ypt7p and the Sec1-related Vps33 protein. While deletion of IVY1 does not lead to any recognized change in phenotype, overexpression of Ivy1p leads to fragmentation of the vacuole, missorting of the vacuolar enzyme carboxypeptidase Y (CPY) to the exterior of the cell, and an accumulation of multivesicular bodies inside the cell. All effects caused by the overexpression of Ivy1p can be reset by simultaneously raising the amount of Vps33p. This suppression activity of Vps33p suggests that Ivv1p and Vps33p at least partially counteract the action of each other in the cell. The intracellular level of Ivy1p increases in cells approaching stationary growth phase at which part of the protein is located at the rim of the vacuole. In addition to its specific interactions with members of two regulatory protein families, Ivy1p in vitro shows a marked propensity for binding phospholipids with high affinity
Kontrolirano izgaranje vodika i kisika u plamenu pri visokom tlaku
In this article the results of experiments of technology of controlled combustion of hydrogen-oxygen flame are presented during the special conditions in high-pressure chamber. The measurement of achieved pressures and temperatures at the controlled process of combustion of hydrogen and oxygen flame was realised as temperature measurement in calibration zone, temperature measurement at the front face of the head, temperature measurement in the pressure chamber and pressure measurement in the pressure chamber.U ovom članku prikazani su rezultati eksperimenata tehnološki kontroliranog izgaranja mješavine vodika i kisika u plamenu tijekom posebnih uvjeta u visokotlačnoj komori. Mjerenja ostvarenih tlakova i temperatura pri kontroliranom procesu izgaranja vodika i kisika u plamenu realizirana su kao mjerenje temperature u zoni kalibracije, mjerenje temperature na prednjoj strani glave, mjerenje temperature u tlačnoj komori i mjerenje tlaka u tlačnoj komori
Vitamin C in the Prevention and Treatment of Frostbite
Two series of experiments were conducted on rats to evaluate the effect of Vit C for prevention and treatment of frostbite. For studies on prevention, 45 rats were divided into 3 groups, as control, Vit C-short term and Vit C-long term. Frostbite was produced experimentally in both the hind limbs by exposing the animals at -15 degree centigrade for 1 h and the assessment of cold injury was done after 15 days. In another study on prevention, frostbite was produced on 20 rats twice, in each limb separately with and without Vit C therapy. The result showed that administration of Vit C for a short period prior to cold exposure period maintained higher rectal temperature and significantly reduced the incidence of frostbite. For studies on treatment, frostbite was produced experimentally in 4 groups of rats. Group I was treated as control, group II was administered 5 mg of Vit C/100 g bw (orally) daily for 15 days. rapid rewarming at 37 degree centigrade on the exposed limbs of group III animals was carried out immediately after cold exposure. Combination of rapid rewarming followed by C therapy was given to group IV. The degree of injury of various groups were compared statistically. Prolonged Vit C therapy as well as waterbath rewarming at body temperature immediately after cold exposure showed significant reduction in tissue damage. High dose of Vit C therapy preceded by rapid rewarming showed additional benefit in reducing the tissue loss
Increased Frequency of Down Syndrome in Young Mothers of Rural Population
Studies were conducted in 222 children clinically diagnosed with Down syndrome (properly diagnosed on the basis of symptoms by Dr. Chandraleka, Pediatrician) to understand the frequency and type distribution of such cases; and to determine the origin of extrachromosome in the 21st pair. Clinical diagnosis was confirmed with karyotyping. Results have shown that nondisjunction or pure trisomy 21 appears to be the main cytogenetic cause; with a percentage frequency of 96.4%; comprising of 114 boys (53.3%) and 108 girls (46.7%). Also the cytological and molecular analysis result revealed that Down syndrome was increased in the young Indian mothers especially in the rural areas.--------------------------------------------------------------------------------------------------------1Department of Advanced Zoology & Biotechnology, Auxillium College, Vellore2School of Bio Sciences & Technology, VIT University, Vellore – 632014*Corresponding author, Email: [email protected] Please Cite This Article As:  R. Regina Mary, K.M. Gothandam, T. Lazar Mathew. 2010. Increased Frequency of Down Syndrome in Young Mothers of Rural Population. Journal of Ecobiotechnology 2/3: 40-44
Two modes of accelerated glacier sliding related to water
We present the first glacier-wide detailed measurement of basal effective pressure and related observations including bed separation to elucidate the role of water in sliding. The hard bedded glacier instrumented in our study exhibited two phases of accelerated sliding motion apparently driven by separate mechanisms. The first acceleration phase (up to 5 fold increase in speed) was closely tied to an increase in bed separation. The faster second phase (up to 9 fold increase in speed) was related to an unusually high level of connectivity of subglacial waters. We infer the first mode was related to cavity opening and the second mode was related to reduced ice contact with the bed. Glacier sliding over a hard bed is typically represented by sliding laws that include the effective basal pressure, but neither sliding phase was accompanied by a simultaneous decrease in local or regional effective pressure
Use of Hyperbaric Oxygen in Experimental Frost-Bite
Frost bite produced in rates by exposing them to -15 degree calcius and the extent of injury in the hind limbs and the tail was assessed at the end of 15 days. Hyperoxic treatment at normal atmospheric pressure and 1.5 atmosphere was given to experimental groups for 30 minutes daily for seven days in a hyperoxic chamber immediately after cold exposure. The controls were not given any treatment. Single oxygen treatment at normal atmosphere pressure was of no value, however, repeated hyperoxic treatment showed limited improvement but repeated treatment for seven days with hyperbaric oxygen at 1.5 atmosphere showed distinct recovery of frozen parts
- …