SYNAPT G2 HDMS高清质谱性能特点及应用简介

SYNAPT~(TM) G2 HDMS质谱分析系统是沃特世公司第二代基于高效离子淌度(ion mobility spectrometry,IMS,也称离子迁移)技术的高性能四极杆-飞行时间质谱仪。通过两种技术的结合与升级,SYNAPT G2 HDMS不仅能按离子的质荷比分离检测,还可根据离子的大小、形状等将其分离。因此,此质谱系统不但可以提高传统质谱数据的准确性,更可以提供样品形态信息,从而得到样品活性、结构状态等信息。其在蛋白组学、代谢组学、糖及脂类分析、医学标志物发掘、药物开发与质控、食品安全检测、环境安全检测等方面有着广泛的应用空间,并已经表现出良好的性能优势,成为各领域工作者的有力的分析工具。本文简要介绍该系统的性能特点及应用。     

Feedforward Controller of Ill-Conditioned Hysteresis Using Singularity-Free Prandtl–Ishlinskii Model

Piezoelectric, magnetostrictive, and shape memory alloy actuators are gaining importance in high-frequency precision applications constrained by space. Their intrinsic hysteretic behavior makes control difficult. The Prandtl-Ishlinskii (PI) operator can model hysteresis well, albeit a major inadequacy: the inverse operator does not exist when the hysteretic curve gradient is not positive definite, i.e., ill condition occurs when slope is negative. An inevitable tradeoff between modeling accuracy and inversion stability exists. The hysteretic modeling improves with increasing number of play operators. But as the piecewise continuous interval of each operator reduces, the model tends to be ill-conditioned, especially at the turning points. Similar ill-conditioned situation arises when these actuators move heavy loads or operate at high frequency. This paper proposes an extended PI operator to map hysteresis to a domain where inversion is well behaved. The inverse weights are then evaluated to determine the inverse hysteresis model for the feedforward controller. For illustration purpose, a piezoelectric actuator is used.     

A Model With Temperature-Dependent Exponent for Hot-Carrier Injection in High-Voltage nMOSFETs Involving Hot-Hole Injection and Dispersion

An improved hot-hole-involved interface-state generation model is proposed for hot-carrier injection (HCI) degradation in high-voltage (HV) nMOSFETs. This model is based on experiments over a wide range of temperatures, voltage conditions, simulation results, and the underlying physical mechanisms. The model provides a thorough picture of an HCI system in HV nMOSFETs, with hot-hole injection related to an additional maximum electric-field region. The hot-hole injection in HCI is assumed to introduce deeper localized hydrogen states in gate-oxide films than that in negative-bias temperature instabilities. This result facilitates the dispersive transport of hydrogen. Therefore, HCI degradation in HV transistors is explained within the framework of disorder-controlled hydrogen kinetics. The power-law model can successfully predict temperature dependences for HCI degradation.     

Investigation of hot carrier degradation in asymmetric nDeMOS transistors

Hot carrier degradation in asymmetric nDeMOS transistors is investigated in this paper. It is found that the worst case hot carrier stress condition in asymmetric nDeMOS transistors is at I_g,max, and not at I_b,max and hot-electron injection (HE, i.e. V_gs = V_ds). Further, the damage regions in transistors upon various hot carrier stress modes are located by using variable amplitude charge pumping technique. It is found that the interface traps generation in the gate/n-type graded drain (NGRD) overlap and spacer/NGRD regions is the dominant mechanism of hot carrier degradation in transistors upon I_g,max stress mode. Moreover, both the interface trap generation and the electron trapping are two important factors to induce the electrical parameters shifts of asymmetric nDeMOS transistors under I_b,max and HE stress.     

Cysteine‐Rich Antifungal Proteins from Filamentous Fungi are Promising Bioactive Natural Compounds in Anti‐Candida Therapy

The emerging number of life‐threatening invasive fungal infections caused by drug‐resistant Candida strains urges the need for the development and application of fundamentally new and safe antifungal strategies in the clinical treatment. Recent studies demonstrated that the extracellular cysteine‐rich and cationic antifungal proteins (crAFPs) originating from filamentous fungi, and de novo designed synthetic peptide derivatives of these crAFPs provide a feasible basis for this approach. This mini‐review focuses on the global challenges of the anti‐Canidia therapy and on the crAFPs as potential drug candidates to overcome existing problems. The advantages and limitations in the use of crAFPs and peptide derivatives compared to those of conventional antifungal drugs will also be critically discussed.     

Multivariate data analyses of persistent organic pollutants in maternal adipose tissue in Singapore

Persistent organic pollutants (POPs) were detected in 88 maternal adipose tissue samples collected during year 2004 to 2006, in Singapore. Organochlorine pesticides (OCPs) were the most dominant followed by polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Multivariate data analyses (MVA) including principal component analysis (PCA), partial least-squares regression (PLSR), and partial least-squares discriminant analysis (PLS-DA) were applied to elucidate the relationship between concentrations of POPs in adipose tissues and donors' characteristics. Food consumption played the most significant role in accounting for levels of POPs in adipose tissue. Fish and poultry consumption was the route of PCBs and PBDEs in mothers in Singapore, while beta-HCH came mainly from vegetables. An age-dependent accumulation of POPs was found for beta-HCH and PCB congeners, and lactation and gestation functioned as a decontamination processes for PCBs in adipose tissue. Gestational diabetes mellitus (GDM) may change the profile of POPs in adipose tissue, probably due to an alteration in lipid metabolism. POPs investigated here may not be the cause of antenatal complication in pregnant women, and baby gender was not related to the pattern of contaminants in maternal adipose tissue.     

Survival of SA11 rotavirus in fresh fruit juices of pineapple, papaya, and honeydew melon

Survival of rotavirus in fresh fruit juices of papaya (Caraca papaya L.), honeydew melon (Cucumis melo L.), and pineapple (Ananas comosus [L.] Merr.) was studied. Clarified juices were prepared from pulps of ripe fruits and sterilized by ultrafiltration. One milliliter of juice from each fruit was inoculated with 20 microl of 1 x 10(6) PFU of SA11 rotavirus and sampled immediately (0-h exposure) and 1 and 3 h later at 28 degrees C. Mean viral titers in juices of papaya (pH 5.1) and honeydew melon (pH 6.3) at 1 and 3 h were not significantly different from titers at 0-h exposure. Mean viral titers in juices from pineapples with ripening color indices of 3 (pH 3.6) and 6 (pH 3.7) at 1-h exposure (color index 3: 4.0 +/- 1.7 x 10(4); color index 6: 2.3 +/- 0.3 x 10(5)) and 3-h exposure (color index 3: 1.1 +/- 0.4 x 10(4); color index 6:1.3 +/- 0.6 x 10(5)) were significantly lower than titers at 0-h exposure (color index 3: 5.7 +/- 2.9 x 10(5); color index 6: 7.4 +/- 1.3 x 10(5)). Virus titers in pineapple juices of color index 3 were significantly lower than titers of the virus in juices of index 6. In cell culture medium (pH 7.4), SA11 titer remained stable over 3 h at 28 degrees C. However, at pH 3.6, the virus titer was reduced to a level not significantly different from that of the virus in pineapple juice of color index 6 (pH 3.7). In conclusion, papaya and honeydew melon juices, in contrast to pineapple juice, have the potential to transmit rotavirus. Inactivation of SA11 virus in pineapple juice can be possibly attributed to low pH and constituent(s) in the juice.     

Mass spectrometry-based "omics" technologies in cancer diagnostics

Many "omics" techniques have been developed for one goal: biomarker discovery and early diagnosis of human cancers. A comprehensive review of mass spectrometry-based "omics" approaches performed on various biological samples for molecular diagnosis of human cancers is presented in this article. Furthermore, the existing and potential problems/solutions (both de facto experimental and bioinformatic challenges), and future prospects have been extensively discussed. Although the use of present omic methods as diagnostic tools are still in their infant stage and consequently not ready for immediate clinical use, it can be envisaged that the "omics"-based cancer diagnostics will gradually enter into the clinic in next 10 years as an important supplement to current clinical diagnostics.     

A galerkin finite element scheme for the rectangular gas-lubricated slider bearing — the transient case

A finite element method for the computation of pressures and load-bearing characteristics of gas-lubricated slider bearings is presented. Steady state bearing characteristics are established by integrating the time-dependent equations. Results are presented for some test problems, including a rectangular slider bearing and two one-dimensional problems for which analytic solutions are known.     

A Soft Resistive Acoustic Sensor Based on Suspended Standing Nanowire Membranes with Point Crack Design

An artificial basilar membrane (ABM) is an acoustic transducer that mimics the mechanical frequency selectivity of the real basilar membrane, which has the potential to revolutionize current cochlear implant technology. While such ABMs can be potentially realized using piezoelectric, triboelectric, and capacitive transduction methods, it remains notoriously difficult to achieve resistive ABM due to the poor frequency discrimination of resistive‐type materials. Here, a point crack technology on noncracking vertically aligned gold nanowire (V‐AuNW) films is reported, which allows for designing soft acoustic sensors with electric signals in good agreement with vibrometer output—a capability not achieved with corresponding bulk cracking system. The strategy can lead to soft microphones for music recognition comparable to the conventional microphone. Moreover, a soft resistive ABM is demonstrated by integrating eight nanowire‐based sensor strips on a soft trapezoid frame. The wearable ABM exhibits high‐frequency selectivity in the range of 319–1951 Hz and high sensitivity of 0.48–4.26 Pa^?1. The simple yet efficient fabrication in conjunction with programmable crack design indicates the promise of the methodology for a wide range of applications in future wearable voice recognition devices, cochlea implants, and human–machine interfaces.