785 research outputs found
C. C. Mehta
No full textOn the life and works of Chandravadan Chimanlal Mehta, b. 1901, Gujarati author
THE ROLE OF B CELLS IN THE T CELL DEPENDENT RELEASE OF HUMAN B CELL GROWTH FACTOR
No full textQuiescent human B cells are postulated to go through activation and proliferation phases before undergoing differentiative phase for immunoglobulin secretion. The present studies address some of the aspects of activation and proliferation phase of normal human B cells. The definitions of signals responsible for B cell activation and proliferation resulted in the development of a highly specific, reproducible B cell growth factor (BCGF) assay. This BCGF bioassay utilizes activation by rabbit anti-human IgM-antibody. The functional specificity of this assay for measuring BCGF activity was demonstrated by the finding that target B cells proliferated but did not differentiate. The factor specificity was determined by specific absorption of BCGF by anti-IgM activated B cells. This assay was utilized for the studies of T-B cell collaboration and the essential function of monocytes in the production and/or release of B cell growth factor in a syngeneic in vitro system. It is apparent that highly purified T cells are poor producers of BCGF by themselves and require monocytes to secrete significant quantities of BCGF upon PHA stimulation. Macrophage soluble factor, Interleukin 1, is capable of replacing monocyte function for the release of BCGF by activated T cells. In our studies, B cells are incapable to function as accessory cells to replace monocyte function. Normal B cells are also not capable of producing BCGF under our experimental observations. However, the addition of these B cells at an optimum cell density (T:B ratio 1:1) doubles the monocyte dependent release of BCGF by syngeneic T cells. The augmentative role of B cells is expanded to understand the mechanism of BCGF release by T cells. It is observed from our studies that DR antigen of B cell surface is involved in the release of BCGF. The functional difference between DR of B cells and monocytes is observed as IL-1 could replace DR-treated monocytes whereas failed to replace DR-treated B cells for the release of BCGF by T cells. This functional difference may be attributed to the reported microheterogeneity in DR of B cells and monocytes. The addition of irradiated B cells increased the monocyte dependent T cell proliferation, suggesting the increase of T cell pool for BCGF release. In summary, the development of a biological assay specific for B cell growth factor led to the delineation of an interesting role of B cells in the release of its own growth factor by T cells. . . . (Author\u27s abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UM
Recommended from our members
Studies Pertaining to Amide C–N Bond Activation and Strained Heterocyclic Allenes
No full textThis dissertation describes the development of reaction methodologies that utilize unconventional building blocks. One major effort involves the development of a strategy to improve the practicality of the nickel-catalyzed Suzuki–Miyaura cross-coupling of amide electrophiles and a strategy for a base-mediated reduction of ketones to secondary alcohols. Furthermore, a one-pot reductive arylation of amides wherein two different nucleophiles are added to the amide carbonyl carbon is reported. This reaction, which proceeds by way of a sequential nickel-catalyzed Suzuki–Miyaura coupling and base-catalyzed reduction cascade process, directly converts amide starting materials to chiral secondary alkyl–aryl alcohol products. Finally, investigations into strained heterocyclic allenes are described. These studies detail the cyclic allene approach to the core of the manzamine alkaloid keramaphidin B, where the key step hinges on a cycloaddition of an azacyclic allene intermediate. Furthermore, the parameters controlling the regioselectivity of the Diels–Alder cycloaddition of heterocyclic allenes with a-pyrones is reported. Each of the methodologies presented is expected to expand the synthetic toolbox by leveraging unique reactivity
Visual outcomes of bilateral congenital and developmental cataracts in young children in south India and causes of poor outcome.
No full textCONTEXT: Bilateral pediatric cataracts are important cause of visual impairment in children. AIM: To study the outcome of bilateral pediatric cataract surgery in young children. SETTING AND DESIGN: Retrospective case series in a tertiary center. MATERIALS AND METHODS: Records of pediatric cataracts operated between January 2001 and December 2003, with a minimum follow-up of 3 months, were reviewed retrospectively. STATISTICAL METHODS: Independent sample t-test, Fisher's exact test, and logistic regression using SPSS (Statistical Package for Social Science, Chicago, USA) version 12. RESULTS: 215/257 (83.7%) patients had a minimum follow-up of 3 months. The mean age of presentation to the hospital was 53 months (range: 0-168 months). Congenital cataract was present in 107 patients (58.2%) and developmental cataract in 77 patients (41.8%). The mean age at surgery was 55.2 months (range: 1-168 months). Out of 430 eyes, 269 (62.6%) had an intraocular lens implanted. The mean duration of follow-up was 13.1 months (range: 3-38 months). Pre-operatively, 102 patients (47.3%) had visual acuity 6/18. The most common early post-operative complication was fibrinous uveitis in 57 eyes (13.3%) and the most common delayed post-operative complication was posterior capsular opacification in 118 eyes (27.4%). The most important prognostic factor for poor outcome was congenital cataract (odds ratio [OR]: 26.3; 95% confidence interval [CI], 4.4-158.5) and total cataract (OR: 4.8; 95% CI, 1.3-17). CONCLUSION: Nearly half of the eyes had visual acuity >6/18. The outcome was poorer in congenital cataracts, especially those operated after >1 year of age
Multi-disciplinary Design Optimization of a Rotor for an Offshore Wind Turbine: A comparison of static and dynamic models
No full textCurrently, the design approach in the wind industry is to perform sequential optimization of different disciplines like wake aerodynamics, turbine, support structure, etc., which might fail to capture the interactions between these disciplines, leading to a sub-optimal design. Literature suggests that a Multi-disciplinary Design Analysis and Optimization (MDAO) tool that integrates all the different disciplines of a wind farm results in a lower LCOE value compared to the conventional approach. However, of all the existing tools, some of them lack user agility (do not cater to all the stakeholders of a wind farm), demand high computational resources, or use low fidelity models. This thesis deals with the wind turbine discipline, with a focus on rotor optimization. The existing framework of WINDOW (the tool being developed at TU Delft) uses a low fidelity static model for the rotor, with a safety factor of 1.5 to account for the missing dynamic effects of loading. To study the implications of the same, a high fidelity dynamic model with an aero-servo-elastic coupling, is integrated into WINDOW, and the differences resulting in the optimized design, from the two models, are evaluated.Electrical Engineering | Sustainable Energy Technolog
Motion planning with task scheduling in heterogeneous computing systems
No full textIncludes bibliographical references.2023 Summer.Motion planning is an important problem in many contexts of
robotics. Heterogeneous computing systems in robots are able to run
tasks on different processing units in varying orders, but with
different impacts on the robot's state and performance. Currently
existing sampling-based motion planning frameworks explore a state
space through typically random sampling to create a path to a goal
region, but only consider physical obstacles in their way such as
walls, and do not consider the constraints of computational
requirements on the path or the impacts of choosing different
schedules for computation. We introduce a novel system which uses
Petri nets as a modeling system on the computational requirements, and
uses constraint solvers to find computation schedules for the motion
planning tasks. This allows us to select motions based not only on
their physical validity, but also computation-related parameters. We
subdivide a space of constraints on the system into regions, enabling
schedule reuse in order to improve the algorithm's efficiency. We also
discuss the use of Petri nets to model another aspect of computation
in a heterogeneous environment, memory contention. Our system enables
us to consider physical dynamics such as heat and power in a way that
prior systems are not capable. We demonstrate that our system can
handle a variety of constraints of different severities, and can avoid
computational obstacles more effectively than na\"ive planning systems
which do not consider computational constraints and instead disallow
regions as though they are physical obstacles
The nematic-isotropic phase transition in semiflexible fused hard-sphere chain fluids
No full textA density-functional theory of the isotropic-nematic phase transition in both rigid and semiflexible hard-sphere chain fluids is described. The theory is based on an exact analytical evaluation of the excluded volume and second virial coefficient B-2 for rigid chain molecules, which demonstrates that B-2 in these cases is equivalent to that of a binary mixture of hard spheres and hard diatomic molecules. It is assumed that the same binary-mixture representation applies to semiflexible chains, while scaled particle theory is used to obtain the properties of the fluid at arbitrary densities. The results of the theory are in very good agreement with Monte Carlo (MC) simulation data for rigid tangent hard-sphere chains, but in lesser agreement with available MC studies of rigid fused hard-sphere chains. We find that there is reasonable agreement between the theory and MC data for semiflexible tangent chains, which improves with increasing chain length. The behavior predicted by the theory for semiflexible chains is contrasted with that given by the Khokhlov and Semenov theory of nematic ordering of wormlike polymer chains. (C) 2001 American Institute of Physics.PT: J; CR: BOUBLIK T, 1974, MOL PHYS, V27, P1415 BOUBLIK T, 1975, J CHEM PHYS, V63, P4084 BOUBLIK T, 1977, CHEM PHYS LETT, V46, P315 BOUBLIK T, 1981, MOL PHYS, V44, P1369 BOUBLIK T, 1989, MOL PHYS, V68, P191 BOUBLIK T, 1990, J CHEM PHYS, V93, P730 CARNAHAN NF, 1969, J CHEM PHYS, V51, P635 CHAPMAN WG, 1988, MOL PHYS, V65, P1057 CHEN ZY, 1993, MACROMOLECULES, V26, P3419 COSTA LA, 1995, J CHEM PHYS, V102, P6212 COTTER MA, 1977, J CHEM PHYS, V66, P1098 COTTER MA, 1978, PHYS REV A, V18, P2669 DIJKSTRA M, 1995, PHYS REV E A, V51, P5891 ESCOBEDO FA, 1997, J CHEM PHYS, V106, P9858 FYNEWEVER H, 1998, J CHEM PHYS, V108, P1636 GAO J, 1989, J CHEM PHYS, V91, P3168 HONNELL KG, 1989, J CHEM PHYS, V90, P1841 JAFFER KM, 1999, J CHEM PHYS, V110, P11630 KHOKHLOV AR, 1981, PHYSICA A, V108, P546 KHOKHLOV AR, 1982, PHYSICA A, V112, P605 LEE SD, 1987, J CHEM PHYS, V87, P4972 MEHTA SD, 1996, J PHYS CHEM-US, V100, P10408 MULLER M, 1998, PHYS REV E, V57, P6973 ONSAGER L, 1949, ANN NY ACAD SCI, V51, P627 PARSONS JD, 1979, PHYS REV A, V19, P1225 PATRA CN, 2000, J CHEM PHYS, V112, P1579 SEN S, 1994, J CHEM PHYS, V101, P9010 VARGA S, 2000, MOL PHYS, V98, P693 VEGA C, 1994, J CHEM PHYS, V100, P6727 WALSH JM, 1990, J PHYS CHEM-US, V94, P5115 WERTHEIM MS, 1987, J CHEM PHYS, V87, P7323 WHITTLE M, 1991, MOL PHYS, V72, P247 WILLIAMSON DC, 1995, MOL PHYS, V86, P819 WILLIAMSON DC, 1998, J CHEM PHYS, V108, P10294 YETHIRAJ A, 1992, MACROMOLECULES, V25, P3979 YETHIRAJ A, 1995, J CHEM PHYS, V102, P5499 YETHIRAJ A, 1995, J CHEM PHYS, V102, P6874 YETHIRAJ A, 1998, MOL PHYS, V93, P693 ZHOU YQ, 1995, J CHEM PHYS, V103, P2688; NR: 39; TC: 8; J9: J CHEM PHYS; PG: 11; GA: 397THSource type: Electronic(1
- …
