Deuterium Effect on Thermal Decomposition of Deuterated Gap: 1. Slow Thermal Analysis with a TGA-DTA-FTIR-MS

The knowledge of the degradation mechanisms of propellants is a key factor in understanding some performance issues of chemical propulsion systems. The thermal decomposition of GAP and a deuterated analog was studied. Thermogravimetric analyses coupled to differential thermal analysis, Fourier transform infrared spectrometry, and mass spectrometry were employed to evaluate the complete decomposition profile of GAPs. Evidence of labeled gaseous compounds were found both in mass spectra and in the FTIR spectra, where new frequencies associated with isotopic labeled gaseous products were detected. An imine-bearing species was detected among the decomposition products, apparently originating from the breakdown of the azide group.     

纳米Al粉的热脱附研究（英）

纳米Al粉有独特热行为,能增强某些含能材料的性能.然而,纳米Al粉与水的反应性高,导致纳米Al粉＂老化＂,降低了它在含能复合材料中的作用.由于纳米Al粉的老化反应与吸附至其表面的水有关,因此应特别关注水的吸、脱附作用.本文用TG和TG-FTIR-MS研究了纳米Al粉吸附气体的热脱附.结果表明,所研究的纳米Al粉含12%（质量）的吸附气体.用FTIR和MS检测到水和CO2的脱附.用多重加热速率和等温研究,得到了吸附气体的脱附过程动力学参数.对不同方法得到的脱附活化能进行了比较.     

Application of Neuron-Selective Fluorescent Probe,NeuA, To Identify Mouse Retinal Degeneration

The retina is part of the central nerve system (CNS) and has various interneurons and sensory neurons such as photoreceptor cells. Retinitis pigmentosa (RP) is an inherited condition that is characterized by photoreceptor degeneration. Herein, we developed a fluorescent probe-NeuA-for detecting retinal neuronal cells and applied NeuA to discriminate between healthy and RP retinas. The staining pattern of NeuA in the retinas of healthy and RP mouse models was examined in vitro, ex vivo and in vivo using confocal microscopy, the fluorescent fundus microscopy and optical coherent tomography (OCT). NeuA strongly stained the outer segment layer of photoreceptor cells and some bipolar cells in the healthy retina, but there was only weak staining in the photoreceptor degenerated retinas. Therefore, NeuA probe can be used as the detecting RP tools in the preclinical conditions.     

Assessment of analytical reproducibility of 1H NMR spectroscopy based metabonomics for large-scale epidemiological research: the INTERMAP Study

Large-scale population phenotyping for molecular epidemiological studies is subject to all the usual criteria of analytical chemistry. As part of a major phenotyping investigation we have used high-resolution 1H NMR spectroscopy to characterize 24-h urine specimens obtained from population samples in Aito Town, Japan (n = 259), Chicago, IL (n = 315), and Guangxi, China (n = 278). We have investigated analytical reproducibility, urine specimen storage procedures, interinstrument variability, and split specimen detection. Our data show that the multivariate analytical reproducibility of the NMR screening platform was >98% and that most classification errors were due to urine specimen handling inhomogeneity. Differences in metabolite profiles were then assessed for Aito Town, Chicago, and Guangxi population samples; novel combinations of biomarkers were detected that separated the population samples. These cross-population differences in urinary metabolites could be related to genetic, dietary, and gut microbial factors.     

An Activity-Based Nanosensor for Minimally-Invasive Measurement of Protease Activity in Traumatic Brain Injury

Current screening and diagnostic tools for traumatic brain injury (TBI) have limitations in sensitivity and prognostication. Aberrant protease activity is a central process that drives disease progression in TBI and is associated with worsened prognosis, thus direct measurements of protease activity can provide more diagnostic information. In this study, a nanosensor is engineered to release a measurable signal into the blood and urine in response to activity from the TBI-associated protease calpain. Readouts from the nanosensor are designed to be compatible with ELISA and lateral flow assays, clinically-relevant assay modalities. In a mouse model of TBI, the nanosensor sensitivity is enhanced when ligands that target hyaluronic acid are added. In evaluation of mice with mild or severe injuries, the nanosensor identifies mild TBI with a higher sensitivity than the biomarker glial fibrillary acidic protein (GFAP). This nanosensor technology allows for measurement of TBI-associated proteases without the need to directly access brain tissue and has the potential to complement existing TBI diagnostic tools.