Studies of emission in the far-infrared and submillimeter from astrophysical sources require large arrays of detectors containing hundreds to thousands of elements. A multiplexed readout is necessary for practical implementation of such arrays, and can be developed using SQUIDS, such that, e.g., a 32 × 32 array of bolometers can be read out using 100 wires rather than the >2000 needed with a brute force expansion of existing arrays. These bolometer arrays are made by micromachining techniques, using superconducting transition edge sensors as the thermistors. We describe the development of this multiplexed superconducting bolometer array architecture as a step toward bringing about the first astronomically useful arrays of this design. This technology will be used in the SAFIRE instrument on SOFIA, and is a candidate for a wide variety of other spectroscopic and photometric instruments. 相似文献
Compounds that comprise the erythrina alkaloid class of natural products are based on a tetracyclic spiroamine framework and exhibit a range of biological activities on the central nervous system. Herein, we report a new and efficient total synthesis of this multiple‐ring system based on an intramolecular acylal cyclisation (IAC) approach. Using this methodology, the tetracyclic core was rapidly assembled over a two‐step domino process catalysed by a Lewis acid. The effect of heteroatoms, substituents and ring size on the IAC has also been investigated, and the broad application of this procedure is demonstrated by the synthesis of a library of derivatives in good yields with excellent regioselectivity. 相似文献
We have observed cyclotron resonance in a high-mobility GaAs/AlGaAs two-dimensional electron gas by using the techniques of terahertz time-domain spectroscopy combined with magnetic fields. From this, we calculate the real and imaginary parts of the diagonal elements of the magnetoconductivity tensor, which in turn allows us to extract the concentration, effective mass, and scattering time of the electrons in the sample. We demonstrate the utility of ultrafast terahertz spectroscopy, which can recover the true linewidth of cyclotron resonance in a high-mobility (>10(6) cm(2)V(-1)s(-1)) sample without being affected by the saturation effect. 相似文献
While cancer now impacts the health and well-being of more of the human population than ever before, the exponential rise in antimicrobial resistant (AMR) bacterial infections means AMR is predicted to become one of the greatest future threats to human health. It is therefore vital that novel therapeutic strategies are developed that can be used in the treatment of both cancer and AMR infections. Whether the target of a therapeutic agent be inside the cell or in the cell membrane, it must either interact with or cross this phospholipid barrier to elicit the desired cellular effect. Here we summarise findings from published research into the phospholipid membrane composition of bacterial and cancer cell lines and biological samples from cancer patients. These data not only highlight key differences in the membrane composition of these biological samples, but also the methods used to elucidate and report the results of this analogous research between the microbial and cancer fields.This review acts as a repository and comparison of cell membrane phospholipid composition data collected from microbial and cancer fields.相似文献
Vapor‐deposited silicone coatings are attractive candidates for providing insulation in neuroprosthetic devices owing to their excellent resistivity, adhesion, chemical inertness and flexibility. A biocompatibility assessment of these coatings is an essential part of the materials design process, but current techniques are limited to rudimentary cell viability assays or animal muscle implantation tests. This article describes how a recently developed in vitro model of glial scar formation can be utilized to assess the biocompatibility of vapor‐deposited silicone coatings on micron‐scale wires. A multi‐cellular monolayer comprising mixed glial cells was obtained by culturing primary rat midbrain cells on poly(D ‐lysine)‐coated well plates. Stainless steel microwires were coated with two novel insulating thin film silicone polymers, namely poly(trivinyltrimethylcyclotrisiloxane) (polyV3D3) and poly(trivinyltrimethylcyclotrisiloxane–hexavinyldisiloxane) (polyV3D3–HVDS) by initiated chemical vapor deposition (iCVD). The monolayer of midbrain cells was disrupted by placing segments of coated microwires into the culture followed by immunocytochemical analysis after 7 d of implantation. Microglial proximity to the microwires was observed to correlate with the amount of fibronectin adsorbed on the coating surface; polyV3D3–HVDS adsorbed the least amount of fibronectin compared to both stainless steel and polyV3D3. Consequently, the relative number of microglia within 100 µm of the microwires was least on polyV3D3–HVDS coatings compared to steel and polyV3D3. In addition, the astrocyte reactivity on polyV3D3–HVDS coatings was lower compared to stainless steel and polyV3D3. The polyV3D3–HVDS coating was therefore deemed to be most biocompatible, least reactive and most preferable insulating coating for neural prosthetic devices.
Household dust can be a major source of human exposure to environmental contaminants such as polybrominated diphenyl ethers, pesticides, and other compounds. This work shows a screening technique that may be used to identify components in an environmental sample as xenobiotics based on mass spectral characteristics of classes of compounds that may be expected to be present in the environment. Household dust (SRM-2585) from the National Institute of Standards and Technology (NIST) was extracted with hexane using accelerated solvent extraction. Large molecules, such as triglycerides and fatty acids were removed with gel permeation chromatography. The extract was then concentrated and analyzed by comprehensive two dimensional gas chromatography coupled to a time of flight mass spectrometer. The resulting peak table was automatically filtered to identify compound classes such as phthalates, polycyclic aromatic hydrocarbons and their heterocyclic analogs, chlorinated compounds, brominated compounds, and nitro compounds. While phthalates can be identified by abundances at specific masses, the identification of the remaining classes is based on the identification of the molecular ion and identification of isotope clusters or other spectral characteristics. The technique detected compounds identified and quantified by NIST as well as compounds not identified by NIST in the sample. By comparison with concentrations determined by NIST for the analytes found, the technique is able to identify analytes in these compound classes at concentrations as low as 10–20 ng/g dust. 相似文献