The interaction of proteins with surfaces is important in numerous applications in many fields-such as biotechnology, proteomics, sensors, and medicine--but fundamental understanding of how protein ...stability and structure are affected by surfaces remains incomplete. Over the last several years, molecular simulation using coarse grain models has yielded significant insights, but the formalisms used to represent the surface interactions have been rudimentary. We present a new model for protein surface interactions that incorporates the chemical specificity of both the surface and the residues comprising the protein in the context of a one-bead-per-residue, coarse grain approach that maintains computational efficiency. The model is parameterized against experimental adsorption energies for multiple model peptides on different types of surfaces. The validity of the model is established by its ability to quantitatively and qualitatively predict the free energy of adsorption and structural changes for multiple biologically-relevant proteins on different surfaces. The validation, done with proteins not used in parameterization, shows that the model produces remarkable agreement between simulation and experiment.
Single-photon spectrometers utilizing optical spectral components and single-photon detectors have shown exceptional spectral resolving capability with single-photon sensitivity, enabling numerous ...spectroscopy applications in photon-scarce environments. Here, we report a compact computational spectrometer combining a superconducting single-photon detector array and 3D-printed photonic-crystal filters. The unknown light source is encoded by passing through the 3D-printed filters with various spectral transmissions, detected by a broadband superconducting single-photon detector array, and finally computationally reconstructed using the known spectral features of each array element. The fabricated spectrometer shows system sensitivity down to powers of −108.2 dBm at 1310 nm and achieves a resolution of 5 nm ranging from 1200 to 1700 nm.
Transparent chromium doped Y3Al5O12 ceramics with excellent optical qualities were successfully fabricated by solid state reaction sintering using divalent dopants (CaO and MgO) as sintering aids, ...and the conversion efficiency of Cr4+ ion in Cr: YAG ceramic was effectively regulated by various approaches. All samples were fully transparent after vacuum sintered at 1820 °C for 8 h. It was found that under fixed amount of divalent dopants, the conversion efficiency of Cr4+ ion in Cr: YAG ceramics was significantly increased by increasing Cr doping concentration, elevating annealing temperature, prolonging annealing soaking time or adopting oxygen annealing atmosphere. The absorption coefficient of as fabricated 0.1 at.% Cr: YAG ceramics at 1030 nm reached up to 5.2 cm−1 after annealed at 1300 °C for 30 h under an oxygen atmosphere. It was much higher than that of corresponding single crystal fabricated by traditional Czochralski method.
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•Transparent Cr: YAG ceramics with excellent optical qualities were fabricated.•The conversion efficiency of Cr4+ was successfully regulated.•The optical quality of Cr: YAG ceramics relies on annealing process.•The absorption coefficient of 0.1 at. % Cr: YAG ceramics was 5.2 cm−1.
We study the effects of the fourth quark generation model in Bs→π^-K^＋ decay. Combining with the up-to-date experimental measurement for B（Bs→π^-K^＋） dir - and Acp ^dir（Bs→π^-K^＋） by the CDF ...Collaboration, we derive the new bound of weak phase Фbd, which are 0° 〈 Фbd 〈 44°,321° 〈 Фbd 〈 360° and 0° 〈 Фbd 〈 26°, 342° 〈Фbd 〈 360° for mr, ： 400 and 600 GeV respectively. In these regions, B（Bs→π^-K^＋） and Acp^dir （Bs→π^-K^＋） consist with the current experimental data within errors.
Antimicrobial peptides, because of their unique structural and chemical properties, hold a promising future for the development of a new class of bacterial-resistant antibiotics, effective ...antimicrobial coatings, and high performance biosensors. To understand the structure/function relationship of surface-bound peptides as they relate to such applications, sum frequency generation (SFG) vibrational spectroscopy, coarse grained molecular dynamics simulations, and antimicrobial activity tests were used to characterize both surface peptide structural information and peptide activity. Results from MSI-78, an antimicrobial peptide, chemically immobilized via the N- (nMSI-78) or C-terminus (MSI-78n), demonstrate that the attachment site influences the structure and behavior of surface-bound peptides. Although both immobilized peptides adopt an α-helical structure in aqueous buffer, nMSI-78 stands up and MSI-78n lies down on the surface, as indicated by both SFG and MD simulations. Antimicrobial activity tests indicated that peptides that stand up interact with bacterial cells much quicker than peptides that lie down. We believe that this study provides fundamental insights into how to rationally engineer peptides and substrate surfaces to produce optimized abiotic/biotic interfaces for antimicrobial applications and beyond.
Engineering phase change materials (PCM) to realize superior data storage devices requires a detailed understanding of crystallization kinetics and its temperature dependence. The temperature ...dependence of crystallization differs distinctly between crystallizing from the glassy phase and the undercooled liquid (UCL). Hence, knowing the phase from which crystallization occurs is necessary for predicting the switching ability. Here, we measure the glassy dynamics and crystallization kinetics using calorimetry for heating rates spanning over six orders of magnitude. Our results show that the prominent PCM (Ag,In)-doped Sb2Te (AIST) exhibits a change from crystallizing from the glassy phase to crystallizing from the UCL at a critical heating rate of 5,000 K/s. Above the glass transition, the activation energy of crystallization changes drastically enabling rapid crystallization at elevated temperatures.
Studies regarding the temporal-spatial variability of water source quality are crucial for protecting urban drinking water and for urban planning. With 41 typical drinking water sources in Guangdong ...Province as the research object, this study investigated temporal-spatial trend of different kinds of water sources in different seasons, a subject that has received little attention. The water quality index (WQI) method was used to study the quality of water sources, and the seasonal Kendall testing method was used to analyze the trends in changing water quality. The following results were obtained: (1) Overall, 22 water sources showed tendencies towards improvement and 13 showed a steady trend towards improvement. In addition, 6 sources faced water quality deterioration problems. The quality of the water source and its variations in eastern, northern and western Guangdong are satisfactory. However, the water sources with the poorest quality or that exhibited deteriorative trends were concentrated in the Pearl River Delta. (2) More water sources exhibited improving quality during the non-flood season than during the flood season. In addition, this effect was more pronounced in river-type source water than in reservoir-type source waters. During the flood season, 5 water sources exhibited deteriorative trends. Of these water sources, 3 were river-type. In addition, 18 water sources had improving water quality. Of these, 12 were river-type. During the non-flood season, only 2 river-type water sources exhibited a deteriorative trend. In addition, 19 water sources showed water quality improvements. Of these, 14 were river-type sources. (3) According to the calculated WQI and its temporal variations, this paper suggests that water sources in Guangdong can be classified into four groups, high WQI, saltatory WQI, fluctuant WQI, and low WQI. In addition, the WQI method and seasonal Kendall testing methods are appropriate for investigating the temporal-spatial variability of water source quality and can provide guidance for regional water source planning.
Many studies have shown that cytochrome P450 (CYP) gene polymorphisms are usually associated with an increased risk of cardiovascular and cerebrovascular diseases. To explore the association of ...CYP2C8 and CYP2J2 gene polymorphisms with hypertensive intracerebral hemorrhage (HICH) in the Han Chinese population.
Forty HICH patients and 40 control subjects were recruited for this study. Two single nucleotide polymorphisms (SNP) (rs1058932, rs2275622) in the CYP2C8 gene and two SNPs (rs2271800, rs1155002) in the CYP2J2 gene were selected for genotyping by direct sequencing. Statistical analysis was applied to examine the effect of genetic variation on HICH.
We found that variant alleles of CYP2C8 rs1058932 (A) and rs2275622 (C) were both significantly associated with HICH, especially in females. We also found significant associations of CYP2C8 rs1058932 (A) and rs2275622 (C) variant alleles with poor outcomes in HICH patients, especially in males.
CYP2C8 gene polymorphisms might increase the risk of HICH in the Han Chinese population and might lead to poor outcomes. This finding adds to the body of literature supporting novel therapeutic strategies for HICH.
The Silicon Charge Detector (SCD) is a subdetector of the High Energy Cosmic Radiation Detection payload. The dynamic range of the silicon microstrip detector can be extended by the capacitive ...coupling effect, which is related to the interstrip capacitance and the coupling capacitance. A detector prototype with several sets of parameters was designed and tested in the ion beams at the CERN Super Proton Synchrotron. The capacitive coupling fractions with readout strip and floating strip incidences were studied using the beam test data and SPICE simulation.
