Comparative studies of glycolytic pathways and channeling under in vitro and in vivo modes

This study constructed cell-free glycolytic enzyme systems and compared them to their in vivo functions in Escherichia coli. Under in vitro conditions, flux regulation followed enzyme concentrations and kinetics. In E. coli, only one of the isozymes of phosphofructokinase (PfkA) and fructose-bisphosphate aldolase (FbaA) facilitate Embden-Meyerhof-Parnas (EMP) flux, but under in vitro assays, these isozymes were interchangeable. Additionally, in vitro introduction of the Entner–Doudoroff (ED) pathway improved glycolysis rates, while in vivo overexpression of the ED pathway could not capture significant flux unless its phosphotransferase system (PTS) was knocked out. Lastly, in vivo dynamic ¹³ C-experiments revealed that the labeling order of EMP pathway intermediates was not strictly cascade, indicating intracellular metabolites were not well mixed. These enigmatic observations cannot be fully explained by thermodynamics or substrate level regulations. This article supports the long-time conjecture that EMP enzymes are channeled, and the PTS may be an anchor point to initiate enzyme assemblies. © 2018 American Institute of Chemical Engineers AIChE J, 65: 483–490, 2019     

Amine-immobilized HY zeolite for CO2 capture from hot flue gas

Solid amine-based adsorbents were widely studied as an alternative to liquid amine for post-combustion CO₂ capture (PCC). However, most of the amine adsorbents suffer from low thermal stability and poor cyclic regenerability at the temperature of hot flue gases. Here we present an amine loaded proton type Y zeolite (HY) where the amines namely monoethanolamine (MEA) and ethylenediamine (ED) are chemical immobilized via ionic bond to the zeolite framework to overcome the amine degradation problem. The MEA and ED of 5%, 10% and 20% (mass) concentration – immobilized zeolites were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and N₂ -196 ℃ adsorption to confirm the structure integrity, amine functionalization, and surface area, respectively. The determination of the amine loading was given by C, H, N elemental analysis showing that ED has successfully grafted almost twice as many amino groups as MEA within the same solvent concentration. CO₂ adsorption capacity and thermal stability of these samples were measured using thermogravimetric analyser. The adsorption performance was tested at the adsorption temperature of 30, 60 and 90 ℃, respectively using pure CO₂ while the desorption was carried out with pure N₂ purge at the same temperature and then followed by elevated temperature at 150 ℃. It was found that all the amine@HY have a substantial high selectivity of CO₂ over N₂. The sample 20% ED@HY has the highest CO₂ adsorption capacity of 1.76 mmol·g^-1 at 90 ℃ higher than the capacity on parent NaY zeolite (1.45 mmol·g^-1 only). The amine@HY samples presented superior performance in cyclic thermal stability in the condition of the adsorption temperature of 90 ℃ and the desorption temperature of 150 ℃. These findings will foster the design of better adsorbents for CO₂ capture from flue gas in post-combustion power plants.     

基于FDTW算法的故障录波数据智能比对方法

针对智能变电站保护装置故障录波文件无通道标识信息、难以与同源通道故障录波器录波文件相互对应的问题,提出一种基于快速动态时间规整(fast dynamic time warping, FDTW)算法的故障录波数据智能比对方法。首先,对各厂站提取的故障录波数据进行异常检测,确保故障录波文件中数据的质量。其次,利用拉格朗日插值法进行采样频率转换,解决保护装置与故障录波器采样频率不一致的问题。然后,利用欧氏距离对同源录波文件数据进行波形一致性对齐,以实现时钟同步。最后,使用FDTW算法对无通道标识信息的故障录波数据进行智能比对。算例分析表明,该方法能够对故障录波数据进行一致性处理,可以快速准确地计算待匹配录波波形的相似度,实现同源通道的录波数据匹配,具备较强的稳定性和实时性。     

Function of glucose catabolic pathways in hydrogen production from glucose in Rhodobacter sphaeroides 6016

Purple non-sulfur (PNS) bacteria can convert volatile fatty acids into hydrogen with a high substrate conversion efficiency. However, when PNS bacteria utilize sugars as a carbon source, such as glucose and sucrose, the substrate conversion efficiency is relatively low. In order to investigate the contributions of the glucose catabolic pathways in Rhodobacter sphaeroides 6016 to its hydrogen production, the cfxA gene from the Embden–Meyerhof–Parnas (EMP) pathway, edd from the Entner–Doudoroff (ED) pathway, and kdg from the semi-phosphorylative ED bypass were knocked out to construct the mutant strains edd⁻, cfxA⁻, and kdg⁻, respectively. Additionally, two of these three genes were knocked out to construct the mutant strains kdg⁻edd⁻, kdg⁻cfxA⁻, and cfxA⁻edd⁻. Hydrogen productions by these mutant strains were compared to that of the wild type strain 6016 using 25 mM glucose as a carbon source. Compared to 6016, variations in hydrogen production and growth were detected in the edd mutant strains (kdg⁻edd⁻, cfxA⁻edd⁻, and edd⁻), while no obvious changes were detected in the others. Notably, the kdg⁻edd⁻ mutant did not produce hydrogen, and its maximum growth was 70% less than that of R. sphaeroides 6016. These results indicate that the ED pathway and semi-phosphorylative ED bypass have a governing impact on cell growth and hydrogen production from glucose in R. sphaeroides 6016. The potential synergistic function of the ED pathway and semi-phosphorylative ED bypass and the reasons for the low hydrogen yield from sugar carbon sources in R. sphaeroides 6016 are discussed.     

Artificial bee colony optimization for economic dispatch with valve point effect

In recent years, various heuristic optimization methods have been proposed to solve economic dispatch (ED) problem in power systems. This paper presents the well-known power system ED problem solution considering valve-point effect by a new optimization algorithm called artificial bee colony (ABC). The proposed approach has been applied to various test systems with incremental fuel cost function, taking into account the valve-point effects. The results show that the proposed approach is efficient and robust when compared with other optimization algorithms reported in literature.     

基于LabVIEW的数据采集系统在金属结合剂金刚石砂轮电火花整形上的应用

在本文中，使用霍尔电流电压传感器，数据采集卡，电容测微仪，基于LabVIEW编程语言建立了数据采集系统：通过数据采集系统实时监测金刚石砂轮电火花整形过程，以及测量砂轮圆度。揭示出电火花整形不同阶段电流电压变化的基本规律，而且通过电流和电压图形，可以判断出砂轮是否达到了某一电参数下的整形精度极限：实验结果表明最后整形阶段的微小进给量及低电压、低占空比和高频率的电参数对提高整形精度具有重要作用。基于LabVIEW的数据采集系统的电火花整形技术有助于提高精密整形的精度。W10金刚石砂轮最终可达到小于2μm砂轮圆跳.     

Electron microscopy studies on the formation and evolution of sodium niobate nanoparticles from a polymeric precursor

The objective of this communication is to study by means of electron microscopy the formation of reactive sodium niobate nanoparticles obtained by a novel polymeric precursor route using -malic acid as chelating agent. Conventional electron microscopy and electron-diffraction were used to investigate the crystallization, the particle size evolution and the formation of nanoparticle agglomerates.     

Comparing the effects of age,BMI and gender on severe injury (AIS 3+) in motor-vehicle crashes

Background

The effects of age, body mass index (BMI) and gender on motor vehicle crash (MVC) injuries are not well understood and current prevention efforts do not effectively address variability in occupant characteristics.

Objectives

(1) Characterize the effects of age, BMI and gender on serious-to-fatal MVC injury. (2) Identify the crash modes and body regions where the effects of occupant characteristics on the numbers of occupants with injury is largest, and thereby aid in prioritizing the need for human surrogates that represent different types of occupant characteristics and adaptive restraint systems that consider these characteristics.

Methods

Multivariate logistic regression was used to model the effects of occupant characteristics (age, BMI, gender), vehicle and crash characteristics on serious-to-fatal injuries (AIS 3+) by body region and crash mode using the 2000–2010 National Automotive Sampling System (NASS-CDS) dataset. Logistic regression models were applied to weighted crash data to estimate the change in the number of annual injured occupants with AIS 3+ injury that would occur if occupant characteristics were limited to their 5th percentiles (age ≤ 17 years old, BMI ≤ 19 kg/m²) or male gender.

Results

Limiting age was associated with a decrease in the total number of occupants with head [8396, 95% CI 6871–9070] and thorax injuries [17,961, 95% CI 15,960–18,859] across all crash modes, decreased occupants with spine [3843, 95% CI 3065–4242] and upper extremity [3578, 95% CI 1402–4439] injuries in frontal and rollover crashes and decreased abdominal [1368, 95% CI 1062–1417] and lower extremity [4584, 95% CI 4012–4995] injuries in frontal impacts. The age effect was modulated by gender with older females more likely to have thorax and upper extremity injuries than older males. Limiting BMI was associated with 2069 [95% CI 1107–2775] fewer thorax injuries in nearside crashes, and 5304 [95% CI 4279–5688] fewer lower extremity injuries in frontal crashes. Setting gender to male resulted in fewer occupants with head injuries in farside crashes [1999, 95% CI 844–2685] and fewer thorax [5618, 95% CI 4212–6272], upper [3804, 95% CI 1781–4803] and lower extremity [2791, 95% CI 2216–3256] injuries in frontal crashes. Results indicate that age provides the greater relative contribution to injury when compared to gender and BMI, especially for thorax and head injuries.

Conclusions

Restraint systems that account for the differential injury risks associated with age, BMI and gender could have a meaningful effect on injury in motor-vehicle crashes. Computational models of humans that represent older, high BMI, and female occupants are needed for use in simulations of particular types of crashes to develop these restraint systems.     

Electrodeposition of BiVO4 with needle-like flower architecture for high performance photoelectrochemical splitting of water

Photoelectrochemical (PEC) water splitting is a green and sustainable approach capable of driving mass hydrogen production in the future. To realize this vision, development of a well-performing photoelectrode is highly demanded. In this comprehensive study, electrodeposition technique was applied for fabricating BiVO₄ films by regulating the deposition time from 1 min until 9 min. Interestingly, the morphology, crystallinity, chemical structure, and optical properties of BiVO₄ films depend strongly on the deposition time. It is found that BiVO₄ layer deposited for 7 min with a cross-section thickness of around 321.1–326.5 nm showed the optimum performance, whereby the photocurrent reached up to ~0.32 mA/cm^?2 at 1.23 V vs. RHE. The deposited BiVO₄ represents tiny and long petals, similar to “needle” nanostructures, which is embedded closely into compact agglomerates. Such morphology enables the BiVO₄ films to perform efficiently as photoanode in PEC cells. Besides, high crystallinity is detected from the sharp peaks of XRD and Raman analysis, as well as good light absorption capability that are the main contributors to the enhancement of PEC performance. In addition to the facile fabrication offered by electrodeposition method, the non-toxic attributes and the impressive PEC performance of the optimum BiVO₄ layer could serve as an interesting option for other applications such as gas sensors, solar cells, degradation of pollutants and photocatalytic water splitting.     

Effect of Conditioning Ultrafiltration Membranes on their Performances in Electrodialysis with Ultrafiltration Membrane

Abstract

A recent alternative method based on ultrafiltration membrane stacked in an electrodialysis cell was recently used for the separation of bio‐active high added value charged molecules, such as peptides and polyphenols. However, the ultrafiltration membranes which are uncharged membranes present lower electrical conductivity, in comparison with conventional ion‐exchange membranes. The purpose of this study was to evaluate the effect of conditioning ultrafiltration membranes of different molecular weight cut‐off (MWCO) (10, 20, 50, and 100 kDa) in solution with different ionic strength (distilled water and 0.1 M NaCl_(aq)) on their electrodialytic properties. It appeared that the conditioning solution could have a major impact on the electrical conductivity value of an ultrafiltration membrane and that the final conductivity value after soaking increased with an increase in molecular weight cut‐off. However, the soaking period and solution had no effect on membrane thickness. Furthermore, the electrical conductivity of the membrane was increased after an electrodialysis with ultrafiltration membranes process of a salt solution.