Thermal management of the LSU micro gas chromatograph

Gas chromatography is a technique widely used for the separation and analysis of gas samples. Gas chromatographs are used for environmental maintenance, monitoring sophisticated biological analyses, and to separate components from a mixture of gases for mass spectrometer analysis. There has been a tremendous interest in miniaturization of gas chromatograph systems because of the potential for portability, faster response time, lower dead volume, lower power consumption, and lower cost of operation. Conventional gas chromatography keeps the column at a constant temperature during separation, which is called isothermal analysis. Temperature programming is a mode of gas chromatography in which the column temperature is raised progressively during the course of analysis. Temperature programming facilitates separation of a wider range of components, when compared to isothermal analysis, in less time. No miniaturized gas chromatograph systems with temperature programming capability have been reported to date. A temperature programming cycle was implemented for the LSU microGC. The thermal behavior of the device was modeled using an energy-based approach to determine the thermal power requirements. Two heaters were designed, one heater gave uniform temperature distribution over the LSU microGC column, and the other gave a linear temperature gradient along the length of microGC. The heaters were fabricated by electrodepositing Ni-Cr (97.5-2.5) alloy on silicon substrates. The heaters were integrated with test microGC. A commercial PID controller was integrated with the heater and fan to direct the temperature programming for the LSU microGC. Heating and cooling ramp rates of more than 2.46 oC/sec were obtained

Proteolysis of Human Thrombin Generates Novel Host Defense Peptides

The coagulation system is characterized by the sequential and highly localized activation of a series of serine proteases, culminating in the conversion of fibrinogen into fibrin, and formation of a fibrin clot. Here we show that C-terminal peptides of thrombin, a key enzyme in the coagulation cascade, constitute a novel class of host defense peptides, released upon proteolysis of thrombin in vitro, and detected in human wounds in vivo. Under physiological conditions, these peptides exert antimicrobial effects against Gram-positive and Gram-negative bacteria, mediated by membrane lysis, as well as immunomodulatory functions, by inhibiting macrophage responses to bacterial lipopolysaccharide. In mice, they are protective against P. aeruginosa sepsis, as well as lipopolysaccharide-induced shock. Moreover, the thrombin-derived peptides exhibit helical structures upon binding to lipopolysaccharide and can also permeabilize liposomes, features typical of “classical” helical antimicrobial peptides. These findings provide a novel link between the coagulation system and host-defense peptides, two fundamental biological systems activated in response to injury and microbial invasion

Genomic regions associated with resistance to peanut bud necrosis disease (PBND) in a recombinant inbred line (RIL) population.

Not AvailableParents and 318 F8 recombinant inbred lines (RILs) derived from the cross, TAG 24 × ICGV 86031 were evaluated for peanut bud necrosis disease (PBND) resistance and agronomic traits under natural infestation of thrips at a disease hotspot location for 2 years. Significant genotype, environment and genotype × environment interac‐ tion effects suggested role of environment in development and spread of the disease. Quantitative trait loci (QTL) analysis using QTL Cartographer identified a total of 14 QTL for six traits of which five QTL were for disease incidence. One quantitative trait locus q60DI located on LG_AhII was identified using both QTL Cartographer and QTL Network. Another QTL q90DI was detected with a high PVE of 12.57 using QTL Cartographer. A total of nine significant additive × additive (AA) interactions were detected for PBND disease incidence and yield traits with two and seven interactions displaying effects in favour of the parental and recombinant genotype combinations, respectively. This is the first attempt on QTL discovery associated with PBND resist‐ ance in peanut. Superior RILs identified in the study can be recycled or released as variety following further evaluations.Not Availabl