Rapid and sensitive detection of Salmonella Typhimurium on eggshells by using wireless biosensors

This article presents rapid, sensitive, direct detection of Salmonella Typhimurium on eggshells by using wireless magnetoelastic (ME) biosensors. The biosensor consists of a freestanding, strip-shaped ME resonator as the signal transducer and the E2 phage as the biomolecular recognition element that selectively binds with Salmonella Typhimurium. This ME biosensor is a type of mass-sensitive biosensor that can be wirelessly actuated into mechanical resonance by an externally applied timevarying magnetic field. When the biosensor binds with Salmonella Typhimurium, the mass of the sensor increases, resulting in a decrease in the sensor's resonant frequency. Multiple E2 phage-coated biosensors (measurement sensors) were placed on eggshells spiked with Salmonella Typhimurium of various concentrations (1.6 to 1.6 × 10(7) CFU/cm(2)). Control sensors without phage were also used to compensate for environmental effects and nonspecific binding. After 20 min in a humidity-controlled chamber (95%) to allow binding of the bacteria to the sensors to occur, the resonant frequency of the sensors was wirelessly measured and compared with their initial resonant frequency. The resonant frequency change of the measurement sensors was found to be statistically different from that of the control sensors down to 1.6 × 10(2) CFU/cm(2), the detection limit for this work. In addition, scanning electron microscopy imaging verified that the measured resonant frequency changes were directly related to the number of bound cells on the sensor surface. The total assay time of the presented methodology was approximately 30 min, facilitating rapid detection of Salmonella Typhimurium without any preceding sampling procedures.     

Validation of a headspace solid-phase microextraction procedure with gas chromatography-electron capture detection of pesticide residues in fruits and vegetables

Headspace solid-phase microextraction (HS-SPME) was evaluated for the determination of pesticide residues in fruits and vegetables by gas chromatography with an electron capture detector (GC-ECD). The fibre used was coated with polydimethylsiloxane (100 μm thickness) and the analytical conditions employed have been developed and optimised in a previous work [Chai, M. K., Tan, G. H., & Asha, L. (2008). Optimisation of headspace solid-phase microextraction for the determination of pesticide residues in vegetables and fruits. Analytical Sciences, 24 (2), 273–276]. The results show that the HS-SPME procedure gave a better linear range, accuracy, precision, detection and quantification limits and is adequate for analysing pesticide residues in fruits and vegetables. The average recoveries obtained for each pesticide ranged between 71% and 98% at three fortification levels with the relative standard deviation of less than 5%. Repeatability (0.3–3.7%) and intermediate precision (0.8–2.5%) were shown to be satisfactory. The limits of detection (0.01–1 μg L⁻¹) and the limits of quantification (0.05–5 μg L⁻¹) of these pesticides were much lower than the maximum residue levels (MRL), allowed for fruits and vegetables in Malaysia.     

结合局部全局特征与多尺度交互的三维多器官分割网络

目的 高度适形放射治疗是常用的癌症治疗方法,该方法的有效性依赖于对癌组织和周边多个危及器官（organ at risk,OAR）解剖结构的精确刻画,因此研究三维图像多器官的高精度自动分割具有重要意义。以视觉Transformer(vision Transformer,ViT)和卷积神经网络（convolutional neural network,CNN）结合为代表的三维医学图像分割方法表现出了丰富的应用优势。然而,这类方法往往忽略同一尺度内和不同尺度间的信息交互,使得CNN和ViT特征的提取和融合受限。本文提出一种端到端多器官分割网络LoGoFUNet(local-global-features fusion UNet),旨在应对现有方法的缺陷。方法 首先,针对单一器官分割,提出在同一尺度下并行提取并融合CNN和ViT特征的LoGoF(local-global-features fusion)编码器,并构建了一个端到端的三维医学图像分割多尺度网络M0。此外,考虑到器官内部以及器官之间的相互关系,该方法在M0网络的基础上设计并引入了多尺度交互（multi-scale interacti...     

Quantification and reduction of organic sulfur compound formation in a commercial wood pulping process

This study experimentally quantified the formation of organic sulfur compounds in a commercial SuperBatch kraft pulping process using a laboratory pilot-scale digester. The results indicate that wood chips not only can adsorb HS- but also methyl mercaptan (MM) in the black liquor used for pretreatment during the two pretreatment stages. The absorption rate of MM is much faster than that of HS-. In the third stage of SuperBatch pulping, the rate of formation of MM and dimethyl sulfide (DMS) is very similar to that found in conventional batch kraft pulping processes. The study examined the applicability of the phase transition cooking (PTC) concept for reducing organic sulfur compounds in pulping, previously developed in laboratory batch pulping using a bomb-type digester, in a SuperBatch process. It was confirmed that there is a phase transition point (PTP) corresponding to PTC in SuperBatch pulping beyond which further delignification significantly increases the formation of volatile organic sulfur compounds. The results indicate that a 40% reduction of TRS formation can be achieved by using PTC.     

Palmitic Acid-Lauric Acid/Expanded Graphite as Form-Stable Composite Phase Change Material for Low-Temperature Energy Storage Applications

Low thermal conductivity of binary fatty acid mixture of palmitic and lauric acids(PA-LA) within the value range of 0.15-0.17 W/(m·K) restricts its wide utilization as thermal energy storage material in the active regime of solar heating applications at low operating temperatures. Nevertheless, this mixture as phase change material(PCM) has a suitable phase-change temperature and heat of 36 ℃ and 176.3 J/g, respectively. Hence, the objective of this study is to formulate a novel form-stable comp...     

疲劳损伤在线预报的研究

对机械系统主要零部件实施疲劳过程在线预报，保证系统的安全性和可靠性，有重要的实际工程意义。以神经网络和局部应力应变法为基础，建立了一个疲劳损伤在线预报方法。该方法使得局部应力应变法不仅应用在设计阶段，而且可以根据实际载荷进行疲劳损伤的在线计算，从而进行疲劳破坏的预报。     

以环保约束性指标优化钢铁工业布局

针对中国钢铁工业布局中存在的＂北重南轻＂、＂东多西少＂和城市型钢铁布局较多等问题,指出现有的钢铁工业布局调整尚不能满足中国区域大气污染防治的要求。系统梳理中国近年来颁布的环境空气质量标准、钢铁工业污染物排放标准和环境保护规划方面针对钢铁工业提出的新要求,指出这些新标准、新要求为钢铁工业优化工业布局形成了重要环境保护约束性指标。同时结合这些约束性指标提出了执行特别排放限值、实行污染物减量置换、提高排污费标准、开展排污权交易和鼓励先进技术应用等推进钢铁工业布局优化的政策措施。     

器外预硫化型MoNiP/γ-Al2O3催化剂的加氢脱硫性能研究

以二苯并噻吩为模型化合物，研究了器外预硫化型加氢催化剂MoNiP／γ-Al2O3的加氢脱硫初始活性及其储存稳定性。结果表明，使用不同配方的硫化剂，在反应温度160℃、浸渍温度160℃、浸渍时间4h、氮气热处理温度300℃的条件下制备得到的器外预硫化催化剂的加氢脱硫活性较好，部分可以达到器内预硫化催化剂的效果，但其加氢活性稍弱；二苯并噻吩在器内与器外预硫化催化剂上的加氢脱硫反应的历程类似，但是对于器外预硫化催化剂而言，二苯并噻吩的加氢脱硫主要依赖于氢解历程。器外预硫化催化剂的储存稳定性较好，长期储存后仍可以维持较高的HDS活性。     

硅改性Hβ沸石催化萘异丙基化反应

采用化学液相沉积法对Hβ沸石进行硅改性,并对其催化萘异丙基化反应的性能进行了评价,考察了硅油类型、沉积量和沉积时间对硅改性Hβ沸石催化性能的影响;采用BET、X射线衍射、吡啶吸附-红外光谱和氨吸附-程序升温脱附等方法对Hβ沸石的晶相、孔结构和酸性进行了表征。实验结果表明,采用该方法可在基本不改变Hβ沸石骨架结构、内孔孔体积和内表面性质的前提下,有效钝化Hβ沸石外表面的酸性位,提高Hβ沸石催化萘异丙基化反应的性能。黏度为100mm2/s的硅油是较好的硅改性剂,在硅油沉积量为0.4mL/g、沉积时间为12h时,可达到较好的改性效果,在此条件下进行硅改性对Hβ沸石的孔口有一定的修饰作用,提高了它的择形催化效果,同时还可提高萘的转化率及二异丙基萘和2,6-二异丙基萘的收率,萘的转化率达82.47%,二异丙基萘和2,6-二异丙基萘的收率分别达到33.80%和8.35%。