Antibacterial and Antibiofilm Activities of Novel Antimicrobial Peptides against Multidrug-Resistant Enterotoxigenic Escherichia Coli

Post-weaning diarrhea due to enterotoxigenic Escherichia coli (ETEC) is a common disease of piglets and causes great economic loss for the swine industry. Over the past few decades, decreasing effectiveness of conventional antibiotics has caused serious problems because of the growing emergence of multidrug-resistant (MDR) pathogens. Various studies have indicated that antimicrobial peptides (AMPs) have potential to serve as an alternative to antibiotics owing to rapid killing action and highly selective toxicity. Our previous studies have shown that AMP GW-Q4 and its derivatives possess effective antibacterial activities against the Gram-negative bacteria. Hence, in the current study, we evaluated the antibacterial efficacy of GW-Q4 and its derivatives against MDR ETEC and their minimal inhibition concentration (MIC) values were determined to be around 2~32 μg/mL. Among them, AMP Q4-15a-1 with the second lowest MIC (4 μg/mL) and the highest minimal hemolysis concentration (MHC, 256 μg/mL), thus showing the greatest selectivity (MHC/MIC = 64) was selected for further investigations. Moreover, Q4-15a-1 showed dose-dependent bactericidal activity against MDR ETEC in time–kill curve assays. According to the cellular localization and membrane integrity analyses using confocal microscopy, Q4-15a-1 can rapidly interact with the bacterial surface, disrupt the membrane and enter cytosol in less than 30 min. Minimum biofilm eradication concentration (MBEC) of Q4-15a-1 is 4× MIC (16 μg/mL), indicating that Q4-15a-1 is effective against MDR ETEC biofilm. Besides, we established an MDR ETEC infection model with intestinal porcine epithelial cell-1 (IPEC-1). In this infection model, 32 μg/mL Q4-15a-1 can completely inhibit ETEC adhesion onto IPEC-1. Overall, these results suggested that Q4-15a-1 may be a promising antibacterial candidate for treatment of weaned piglets infected by MDR ETEC.     

Quantum hydrodynamic simulation of discrete-dopant fluctuated physical quantities in nanoscale FinFET

Impact of the discrete dopants on device performance is crucial in determining the behavior of nanoscale semiconductor devices. Atomistic quantum mechanical device simulation for studying the effect of discrete dopants on device's physical quantities is urgent. This work explores the physics of discrete-dopant-induced characteristic fluctuations in 16-nm fin-typed field effect transistor (FinFET) devices. Discrete dopants are statistically positioned in the three-dimensional channel region to examine associated carrier's characteristic, concurrently capturing “dopant concentration variation” and “dopant position fluctuation”. An experimentally validated quantum hydrodynamic device simulation was conducted to investigate the potential profile and threshold voltage fluctuations of the 16-nm FinFET. Results of this study provide further insight into the problem of fluctuation and the mechanism of immunity against fluctuation in 16-nm devices.     

Investigation of Raman enhancement in hydrothermally roughened SERS-active substrates

In this work, we study surface enhanced Raman spectroscopy (SERS) active substrates for the detection of Rhodamine 6G. To examine the electromagnetic enhancement, we apply the finite-difference time-domain (FDTD) algorithm to analyze the structures by solving a set of coupled Maxwell's equations (Ampere's Law and Faraday's Law) in differential form. The field enhancements are thus investigated in the visible regime with the wavelength of 633 nm. In our experimental measurement, the surface enhanced Raman scattering signals from the surface of substrates with 12-hour treatment and without treatment are performed and compared. Through the three-dimensional (3D) FDTD calculation, we find that the hydrothermally 12-hour treated samples possess significantly vertical variations of surface and thus have relatively larger field enhancement than those without treated. Consequently, it implies a strong positive effect on the surface enhancement which is consistent with the measured intensity.     

The effectiveness of using procedural scaffoldings in a paper-plus-smartphone collaborative learning context

The purpose of this study was to evaluate the effectiveness of using procedural scaffoldings in fostering students’ group discourse levels and learning outcomes in a paper-plus-smartphone collaborative learning context. All participants used built-in camera smartphones to learn new knowledge by scanning Quick Response (QR) codes, a type of two-dimensional barcode, embedded in paper-based learning materials in this study. Sixty undergraduate and graduate students enrolled at a four-year university in southern Taiwan participated in this study. Participants were randomly assigned into two different groups, using procedural scaffoldings learning and non-procedural scaffoldings learning. The learning unit about the Long Tail, an important concept used in products sales, was the learning task that participants were expected to complete. During the experiment, pretest–posttest and the completed group worksheets were used to collect data. The researchers applied content analyses, chi-square test, t-test, and ANCOVA to answer research questions. The findings indicated that participants in the experimental group using procedural scaffoldings achieved better learning outcomes than their counterparts in the control group in terms of group discourse levels, group learning, and individual learning.     

The Use of Distinctive Monoclonal Antibodies in FMD VLP- and P1-Based Blocking ELISA for the Seromonitoring of Vaccinated Swine

The serum neutralization (SN) test has been regarded as the “gold standard” for seroconversion following foot-and-mouth disease virus (FMDV) vaccination, although a high-level biosafety laboratory is necessary. ELISA is one alternative, and its format is constantly being improved. For instance, standard polyclonal antisera have been replaced by monoclonal antibodies (MAbs) for catching and detecting antibodies, and inactive viruses have been replaced by virus-like particles (VLPs). To the best of current knowledge, however, no researchers have evaluated the performances of different MAbs as tracers. In previous studies, we successfully identified site 1 and site 2 MAbs Q10E and P11A. In this study, following the established screening platform, the VLPs of putative escape mutants from sites 1 to 5 were expressed and used to demonstrate that S11B is a site 3 MAb. Additionally, the vulnerability of VLPs prompted us to assess another diagnostic antigen: unprocessed polyprotein P1. Therefore, we established and evaluated the performance of blocking ELISA (bELISA) systems based on VLPs and P1, pairing them with Q10E, P11A, S11B, and the non-neutralizing TSG MAb as tracers. The results indicated that the VLP paired with S11B demonstrated the highest correlation with the SN titers (R² = 0.8071, n = 63). Excluding weakly positive serum samples (SN = 16–32, n = 14), the sensitivity and specificity were 95.65% and 96.15% (kappa = 0.92), respectively. Additionally, the P1 pairing with Q10E also demonstrated a high correlation (R² = 0.768). We also discovered that these four antibodies had steric effects on one another to varying degrees, despite recognizing distinct antigenic sites. This finding indicated that MAbs as tracers could not accurately detect specific antibodies, possibly because MAbs are bulky compared to a protomeric unit. However, our results still provide convincing support for the application of two pairs of bELISA systems: VLP:S11B-HRP and P1:Q10E-HRP.     

2016年昆明市学校周边食品及婴幼儿食品卫生安全调查

目的 了解2016年昆明市学校周边食品及婴幼儿食品的卫生状况。方法 采集昆明市区的学校午餐、学校周边流动食品、学校周边即食儿童食品、婴幼儿配方食品及鲜乳共203份样品, 按照国家食品污染和有害因素风险监测工作手册的方法进行检测。结果 203份样品中, 共检出19株蜡样芽胞杆菌, 致病菌检出率为9.4%。其中, 学校周边食品的蜡样芽胞杆菌检出率为18.2%, 婴幼儿食品的蜡样芽胞杆菌检出率为4.0%。结论 昆明市学校周边食品及婴幼儿食品中存在蜡样芽胞杆菌污染, 有一定的安全隐患, 相关监管部门应加强监督, 预防食源性疾病的发生。     

Conversion of hydrogen/carbon dioxide into formic acid and methanol over Cu/CuCr2O4 catalyst

Cu/CuCr₂O₄ catalysts were prepared by impregnation method at various calcination temperatures (300, 400, and 500 °C) and then reduced in H₂ stream. The aggregated particles and decreasing surface area/pore volumes of the deactivated catalysts during HCOOH and CH₃OH formations were also observed. Particularly, the EXAFS data showed that first shells of Cu atoms transforms from Cu–O to Cu–Cu after catalytic reactions, their bond distances and coordination numbers are quite different, respectively. It revealed that metallic Cu atoms are one of the important active species over catalyst surface at different reaction temperatures having many unoccupied binding sites for HCOOH and CH₃OH formations. Additionally, the optimal calcination temperature for Cu/CuCr₂O₄ catalysts was demonstrated at 400 °C that attributed to its strongest acidity and basicity. The catalytic reactions in the duration of HCOOH and CH₃OH preparation were proposed that were composed of HCOOH formation, CH₃OH formation, and CH₃OH decomposition happening at CuCr₂O₄, Cu, and CuO active sites, respectively. The highest CO₂ conversion (14.6%), HCOOH selectivity/yield (87.8/12.8%), and TON/TOF values (4.19/0.84) were obtained at 140 °C and 30 bar in 5 h, respectively. Optimal rate constant (2.57 × 10^?2 min^?1) and activation energy (16.24 kJ mol^?1) of HCOOH formation were evaluated by pseudo first-order model and Arrhenius equation, respectively.     

Regulation of virus-induced inflammatory response by β-carotene in RAW264.7 cells

Carotenoids are effective antioxidants, which can quench singlet oxygen, suppress lipid peroxidation, and prevent oxidative damage. Both Pseudorabies virus (PRV) and human Herpes simplex virus (HSV) are DNA viruses, and their pathogenesis and immunobiology are similar. However, PRV does not infect humans. Therefore, PRV was used to infect murine macrophages (RAW264.7 cells), to mimic HSV-induced inflammation. Meanwhile, the influence of β-carotene on PRV-induced inflammation was also investigated. Results indicated that β-carotene inhibited (p < 0.05) NO, IL-1β, IL-6, and MCP-1 production in PRV-infected RAW264.7 cells. β-Carotene also suppressed (p < 0.05) NF-κB (p50 and p65), phosphorylation of extracellular-signal-related kinase (ERK), p38, and c-Jun N-terminal kinase (JNK) expression. It could be concluded that the anti-inflammatory effect of β-carotene is mainly through a suppression of cytokine expression in PRV-induced inflammation, which results from NF-κB inactivation. β-Carotene can be considered a potential anti-inflammatory agent for DNA-virus infection.     

Optimization on configuration of surface conduction electron-emitters

In this work, a novel nanogap with inclined protrusion cathode in palladium strip fabricated by hydrogen absorption under high-pressure treatment is optimized for the surface conduction electron-emitter. Its field emission is sensitive to the geometry of surface conduction electron-emitters (SCE). For a specified emitter material, the SCE are further investigated by varying the thickness, tilted angle and gap of palladium (Pd). An optimal field emission efficiency with 80° tilted angle, 120 nm gap and 10 nm thickness of Pd is found for certain designed field emission efficiency. We further find that varying the emitter material work function of the emitter material from 5.12 eV to 3.9 eV will further improve the field emission property due to the increase of the emitted current.     

基于CDMA和2.4G通信的无线远程血糖监护网络

目前,针对糖尿病的主要治疗方法为用血糖仪频繁测量患者体内的血糖含量,据此对患者的血糖代谢进行调节.借鉴无线传感器网络及体域网相关的技术与思想,利用CDMA蜂窝移动通信技术与2.4G射频通信技术设计了一个可用于监护个人及小区域内多人血糖情况的无线远程血糖监护网络系统.此血糖监护网络能够实现糖尿病的远程诊疗,拉近医患距离,减轻患者痛苦.重点介绍了血糖监护网络的网络架构,详细描述了网络节点CDMA和2.4G无线通信功能的设计与实现.