发酵辣椒中的微生物及其风味物质研究进展

发酵辣椒即利用微生物在厌氧条件下的分解作用产生各种代谢产物,经过一系列的生物化学变化及物理变化,形成的具有独特发酵风味的辣椒制品。发酵辣椒作为一种传统的辣椒制品,香辣酸脆,开胃可口,符合大众口味,但由于传统自然发酵菌群不明、结果不可控等因素,接种发酵成为目前研制发酵辣椒的热点方法,更是制备具有优良风味的发酵辣椒的关键。该研究介绍了发酵辣椒中的微生物多样性及其检测方法,总结了发酵辣椒中的风味物质,经综合分析得：发酵辣椒中的微生物以乳酸杆菌属和酵母菌属为主,产生酯类、醇类、酸类、烯烃类、醛类等众多复杂的香气成分,烷烃类、烯烃类和萜醇类物质在未发酵成熟的辣椒中是主要呈香物质,同样是辣椒发酵后的部分香气成分,赋予了发酵辣椒独特的花香、果香等香气特征。该研究重点阐述了影响发酵辣椒中风味物质的因素,主要包括发酵原料、发酵方法、发酵菌种、发酵盐度、发酵温度、发酵时间等几个方面,其中发酵原料、发酵菌种以及发酵盐度对于发酵辣椒风味的生成至关重要,此外,该研究还指出了目前研究过程中存在的问题及对未来的展望,以期为发酵辣椒工业化发展提供理论基础。     

Co-Aggregation of S100A9 with DOPA and Cyclen-Based Compounds Manifested in Amyloid Fibril Thickening without Altering Rates of Self-Assembly

The amyloid cascade is central for the neurodegeneration disease pathology, including Alzheimer’s and Parkinson’s, and remains the focus of much current research. S100A9 protein drives the amyloid-neuroinflammatory cascade in these diseases. DOPA and cyclen-based compounds were used as amyloid modifiers and inhibitors previously, and DOPA is also used as a precursor of dopamine in Parkinson’s treatment. Here, by using fluorescence titration experiments we showed that five selected ligands: DOPA-D-H-DOPA, DOPA-H-H-DOPA, DOPA-D-H, DOPA-cyclen, and H-E-cyclen, bind to S100A9 with apparent K_d in the sub-micromolar range. Ligand docking and molecular dynamic simulation showed that all compounds bind to S100A9 in more than one binding site and with different ligand mobility and H-bonds involved in each site, which all together is consistent with the apparent binding determined in fluorescence experiments. By using amyloid kinetic analysis, monitored by thioflavin-T fluorescence, and AFM imaging, we found that S100A9 co-aggregation with these compounds does not hinder amyloid formation but leads to morphological changes in the amyloid fibrils, manifested in fibril thickening. Thicker fibrils were not observed upon fibrillation of S100A9 alone and may influence the amyloid tissue propagation and modulate S100A9 amyloid assembly as part of the amyloid-neuroinflammatory cascade in neurodegenerative diseases.     

Diagnosis of poor control-loop performance using higher-order statistics

Higher-order statistical (HOS) techniques were first proposed over four decades ago. This paper is concerned with higher-order statistical analysis of closed-loop data for diagnosing the causes of poor control-loop performance. The main contributions of this work are to utilize HOS tools such as cumulants, bispectrum and bicoherence to develop two new indices: the non-Gaussianity index (NGI) and the nonlinearity index (NLI) for detecting and quantifying non-Gaussianity and nonlinearity that may be present in regulated systems, and to use routine operating data to diagnose the source of nonlinearity. The new indices together with some graphical plots have been found to be useful in diagnosing the causes of poor performance of control loops. Successful applications of the proposed method are demonstrated on simulated as well as industrial data. This study clearly shows that HOS-based methods are promising for closed-loop performance monitoring.     

Online feature-based multisensor object detection system for bucket-wheel excavators

This paper proposes the development of a monitoring system to be applied for a production system (bucket-wheel excavator). The system is based on a multisensor-based object detection system. The main objective of the detection system is to obtain—in real time—reliable decisions on the presence of large stones in the transported overburden. The highest possible detection rate and the lowest possible false alarm rate should be achieved to avoid disturbances or failures of the production process. Due to the complexity of the considered production system, different physical effects are taken into account. The detection system consists of two detection modules (acceleration and laser scanner module), a plausibility module (weightometer module), and a fusion module. The acceleration module consists of five acceleration sensors. The acceleration signals are individually undergone preprocessing, feature extraction, and classification processes. The preliminary decisions of different sensor channels are fused to obtain statements about the presence of large stones. In the laser scanner module, the signal is prefiltered, filtered, validated, and classified in order to detect excavated stones. The weightometer module is based on two load cells signals. It is developed to approve the plausibility of the positive statements of the acceleration module. The fusion module is developed in order to synchronize and combine the output statements of different modules to obtain the production system state with respect to the presence of an object. The detection system is developed based on the acquired knowledge from the analysis of the production process and the analysis of the acquired data during the production process. The designed system has been implemented using standard industrial hardware. The testing results to be reported show that the system requirements can be fulfilled.     

Validation of a Real-Time PCR On-Site Quantification Method for MON810 Maize

A rapid on-, or near-site, quantitative method for use as a pre-harvest predictive decision, or co-existence monitoring, tool for adventitious genetically modified (GM) presence has been developed. Based on a laboratory-based protocol for real-time (RT) quantification of the MON810 GM event in maize kernels, the duplex RT polymerase chain reaction method was constructed around the portable Cepheid SmartCyclerII platform, requiring only modest support infrastructure for field application. Validation through an international ring trial showed good compliance with minimum assay performance requirements as defined by the European Network of GMO Laboratories (RSD_r = 18.5%; RSD_R = 32.8; Bias = 26.7%).     

Mutation of the protein-O-mannosyltransferase enhances secretion of the human urokinase-type plasminogen activator in Hansenula polymorpha

Human urokinase-type plasminogen activator (uPA) is poorly secreted and aggregates in the endoplasmic reticulum of yeast cells due to inefficient folding. A screen for Hansenula polymorpha mutants with improved uPA secretion revealed a gene encoding a homologue of the Saccharomyces cerevisiae protein-O-mannosyltransferase Pmt1p. Expression of the H. polymorpha PMT1 gene (HpPMT1) abolished temperature sensitivity of the S. cerevisiae pmt1 pmt2 double mutant. As in S. cerevisiae, inactivation of the HpPMT1 gene affected electrophoretic mobility of the O-glycosylated protein, extracellular chitinase. In contrast to S. cerevisiae, disruption of HpPMT1 alone caused temperature sensitivity. Inactivation of the HpPMT1 gene decreased intracellular aggregation of uPA, suggesting that enhanced secretion of uPA was due to improvement of its folding in the endoplasmic reticulum. Unlike most of the endoplasmic reticulum membrane proteins, HpPmt1p possesses the C-terminal KDEL retention signal.     

Monitoring of the Long-term Performance of Stainless Steel Reinforcement in Saline Environments

The aim of the present work is to evaluate the corrosion behaviour of different types of stainless steel reinforcement and to determine their suitability for the use in a chloride contaminated concrete environment. Electrochemical impedance spectroscopy (EIS) measurements were performed on steel reinforcement specimens in a simulated concrete pore solution containing chlorides. The concrete specimens, with embedded electrical resistance (ER) probes for corrosion monitoring, were subjected to cyclic wetting-drying. Reinforced concrete columns with ER probes and coupled multi-electrodes for the measurement of partial currents were exposed to a real marine environment. Traditional stainless steel reinforcement in chloride contaminated environment behaves significantly better than carbon steel. Austenitic low-Ni stainless steel showed similar corrosion resistance to that of the traditional stainless steels, whereas ferritic stainless steel was found to be unsuitable for use in such environments. ER probes and coupled multi-electrodes were shown to be promising methods for corrosion monitoring in concrete.     

穿越活动地裂缝地铁隧道震害机制研究

 通过振动台模型试验对穿越活动地裂缝的地铁隧道的动力响应进行了研究,研究内容主要包括地铁隧道的加速度反应,土压力及应变的变化规律。分析结果表明,穿越活动地裂缝的地铁隧道在地震荷载作用中,活动地裂缝场地产生不均匀沉降,上盘沉降大于下盘区,预设地裂缝部位沉降值最大,不均匀沉降导致次生裂缝及沉降陡坎产生,地铁隧道上方场地土体产生细小裂缝;地铁隧道与活动地裂缝的加速度时程曲线均与地震动荷载加速度时程具有一致性,地铁隧道各部位加速度时程保持一致,说明在地震中地铁运动保持整体性,上盘场地的加速度峰值较大,表明在活动地裂缝中上盘区对地震动力有一定的放大效应;活动地裂缝场地中土压力呈现出动土压力曲线变化,地震加载结束后隧道结构侧向的土压力受力状态及大小均产生变化,隧道结构顶部的土压力有较大增加;应变曲线表明在扩大断面的马蹄形隧道结构中拱腰部位的应变增值最大,拱顶部位次之,底板的应变增值相比最小。以上成果对于合理认识跨越地裂缝的地铁隧道的地震响应特征具有重要意义,可为地铁隧道实际工程设计和施工的抗震设防提供宝贵的基础资料。