Development of a Highly Selective,Sensitive, and Fast Response Upconversion Luminescent Platform for Hydrogen Sulfide Detection

Hydrogen sulfide (H₂S) has been recognized as one of most important gaseous signaling molecules mediated by a variety of physiological and pathological processes. Yet, its functions remain largely elusive due to the lack of potent monitoring methods. Hereby this issue is addressed with a powerful new platform—dye‐assembled upconversion nanoparticles (UCNPs). A series of chromophores with different absorption bands and fast responses towards H₂S is combined with UCNPs and results in a library of H₂S sensors with responsive emission signals ranging from the visible to the near‐infrared (NIR) region. These nanoprobes demonstrate highly selective and rapid responses to H₂S in vitro and in cells. Furthermore, H₂S levels in blood can be detected using the developed nanoprobes. Hence the reported H₂S sensing platform can serve as a powerful diagnostic tool to research H₂S functions and to investigate H₂S‐related diseases.     

生物技术在制浆工业应用的前景

介绍了微生物技术在制浆工业应用的研究情况及其发展前景。主要包括:生物化学制浆、生物机械制浆、生物漂白、废水生物处理、废纸生物脱墨、树脂生物控制等,以及所用真菌或细菌的菌种及其作用原理和处理方法。     

纳米发光材料及器件的研究发展

纳米发光材料及相关器件是近年来国际上的一个研究热点。本文对这方面的主要研究方向如硅基纳米发光材料、纳米粉末发光材料、碳纳米管的场发射等研究进展进行了综述。这些纳米材料在光电集成、信息显示等领域具有重要的学术意义和良好的市场前景。     

Microbial treatment of waxy crude oil for mitigating wax precipitation and improving liquidity

The wax deposition of crude oil during transportation reduces the inner diameter, blocks the pipeline, and eventually increases the cost of petroleum production. This study reports a paraffin-degrading bacterial strain DG2 isolated from petroleum-contaminated soil. The effect of this strain on the removal of paraffin in crude oil was investigated. DG2, identified as Pseudomonas, produced biosurfactant that reduced the surface tension to 35.7?mN/m^?1 and exhibited high emulsification activity. Results of gas chromatography–mass spectrometry analysis of the waxy crude oil treated by DG2 showed decreased heavy hydrocarbon fractions (C25 and C32). The degradation test revealed that DG2 reduced the wax appearance temperature by 4.16?°C and the viscosity by 23% of the waxy crude oil. These findings indicate that paraffin-degradation strain DG2 may be used for effective paraffin biodegradation.     

One-Component Artificial Gustatory System Based on Hydrogen-Bond Organic Framework for Discrimination of Versatile Analytes

Hydrogen-bond organic frameworks (HOFs) with excellent structural and luminescent properties have emerged as a promising material for the construction of fluorescence sensors. However, designing a facile, universal and high throughput sensor with multiplex detection capacity still remains challenging. Herein, a one-component sensor array is constructed that mimics natural gustatory system for accurate and high-throughput discrimination and identification of versatile analytes. HOF as a single sensing element greatly simplifies the probe preparation in sensor array and detection procedure. Metal ions, proteins and bacteria as the model targets are rapid and accurately discriminated, presenting the universality of the system. Particularly, the system is successfully used for the classification of antibiotic mechanisms. The study expands the application scope of HOFs and provides a facile and universal system for sensing applications.     

The polymerase chain reaction: Applications for the detection of foodborne pathogens

Faster methods for the detection of foodborne microbial pathogens are needed. The polymerase chain reaction (PCR) can amplify specific segments of DNA and is used to detect and identify bacterial genes responsible for causing diseases in humans. The major features and requirements for the PCR are described along with a number of important variations. A considerable number of PCR‐based assays have been developed, but they have been applied most often to clinical and environmental samples and more rarely for the detection of foodborne microorganisms. Much of the difficulty in implementing PCR for the analysis of food samples lies in the problems encountered during the preparation of template DNAs from food matrices; a variety of approaches and considerations are examined. PCR methods developed for the detection and identification of particular bacteria, viruses, and parasites found in foods are described and discussed, and the major features of these reactions are summarized.     

Reduction of Streptococcus thermophilus in a whey protein isolate by low moisture extrusion cooking without loss of functional properties

A whey protein isolate powder (WPI) (4–5% water) inoculated with 5x10⁵ viable Streptococcus thermophilus per g, was continuously processed in a twin screw extruder under the following conditions (barrel length = 500 or 1000 mm; screw profile = forward transport and compression elements; moisture content during extrusion = 4–5%; feed rate = 10 kg h^-1; barrel temperature ( T_b ) = 80–204°C; speed of screw rotation = 50 r.p.m.). The minimum residence time determined by pulse injection of erythrosin was 20–25 s (500 mm barrel) or 35–40 s (1000 mm barrel).
Reduction values of viable Streptococcus thermophilus of 10^4.2-fold (500 mm barrel, T_b = 143°C) or 10^4.9-fold (1000 mm barrel, T_b = 133°C) were obtained without any modification of protein solubility or gelling properties. WPI extruded at the highest barrel temperatures (182–204°C) underwent limited browning and reduction of protein solubility. Gel permeation and hydrophobic interaction chromatography of the soluble constituents did not show any aggregates of β-lactoglobulin or α-lactalbumin.
Gels prepared from control or extruded WPI ( T_b 143°C with a barrel length = 500 mm or T_b 133°C with a barrel length = 1000 mm) were identical, as judged by scanning electron microscopy and rheological evaluations.     

新型糖源——低聚异麦芽糖

介绍了一种新型糖源低聚异麦芽糖。它具有低甜度、低热量、不蛀牙的特性。是人体肠道内双歧杆菌的增殖因子,能促进有益菌群在肠道中的繁殖。它是一种具有特殊功能的食品及食品配料。鉴于它的特殊功效,被广泛地应用于医药、保健、食品等领域。     

发酵乳─最新研究动向

有关发酵乳的研究,目前主要集中于新产品的开发和健康特性的研究。在对近１０年有关文献研究的基础上,介绍了发酵乳的种类,益生菌,乳酸菌的培养、代谢特性、遗传和生物技术,发酵剂的制作,健康特性研究及乳酸菌的安全性等。     

Class IIa bacteriocins from lactic acid bacteria: antibacterial activity and food preservation

In the last decade, a variety of ribosomally synthesized antimicrobial peptides, or bacteriocins, produced by lactic acid bacteria have been identified and characterized. As a result of these studies, insight has been gained into various fundamental aspects of biology and biochemistry such as bacteriocin processing and secretion, mechanisms of cell immunity, and structure-function relationships. In parallel, there has been a growing awareness that bacteriocins may be developed into useful antimicrobial food additives. Class IIa bacteriocins can be considered as the major subgroup of bacteriocins from lactic acid bacteria, not only because of their large number, but also because of their significant biological activities and potential applications. The present review provides an overview of the knowledge available for class IIa bacteriocins and discusses common features and recent findings concerning these substances. The activity and potential food applications of class IIa bacteriocins are a major focus of this review.