金属阳离子和硫酸铵对除草剂药效的影响

除草剂的药效受到多种因素的影响,其中作为溶剂水的质量就是一要素,如硬水中钙、镁等金属阳离子,而含有锰、锌等金属阳离子的叶肥也会有影响,它们会对一些除草剂的防效有一定的减弱作用。硫酸铵是传统化肥,它可以增加一些除草剂的防除效果,而且可以减弱金属阳离子和锰、锌叶肥对除草剂除草活性的拮抗作用。     

Study of additive‐additive interactions in a lubricant system by NMR,ESCA, and thermal techniques

Engine oil lubricants are formulated with a variety of additive components at different dosages to obtain the desired physico‐chemical characteristics. Antiwear, friction modification/energy efficiency, dispersancy, and detergency properties are normally achieved by the use of zinc dialkyldithiophosphate (ZDDP), molybdenum dithiocarbamate (MoDTC) and ashless alkyl phosphorodithioate, polyisobutylene succinimide (PIBS), and metal sulphonates / phenates, respectively. It has been reported that these additives interact with each other and affect the overall performance of a lubricant system. The additive‐additive interactions have been studied by nuclear magnetic resonance (NMR) and infrared spectroscopic techniques, where attention has been mainly focused on the ZDDP‐PIBS additive system in the presence or absence of other additives. The results have been used to relate the synergistic or antagonistic effects of such interactions to the overall performance of a lubricant. Recently, MoDTC has found wider application in lubricants as a friction modifier and energy‐efficient additive. However, no studies of the additive‐additive interactions of the PIBS‐MoDTC‐ZDDP additive system using analytical techniques have been reported. The present paper covers the fundamental and mechanistic aspects of additive‐additive interactions of ZDDP, MoDTC, PIBS, and sulphonate / phenate additives present in a lubricant system as studied by ³¹P NMR, electron spectroscopy for chemical analysis (ESCA), and thermogravimetric analysis (TGA) techniques. ESCA, which is a surface analytical technique, has been used to provide basic evidence for the formation of various complexes through interactions occurring in the electronic binding energies of orbitals of various atoms of the additives. The ESCA studies have also revealed the actual atomic sites of interaction between the additives responsible for the formation of adducts or complexes. The differential scanning calorimetry profiles of blends have verified the interactions among the additives and shown that the stability of the additive system is quite different from that of the additives alone. The shifts in the ³¹P NMR signals, the changes in the binding energies of the s, p, and d orbitals of additive elements, and the multistage decomposition profiles in the TGA thermograms of interacting systems due to complexion and adduct formation have enabled a mechanism of interaction to be proposed.     

Microbes versus microbes: control of pathogens in the food chain

Foodborne illness continues as a considerable threat to public health. Despite improved hygiene management systems and increased regulation, pathogenic bacteria still contaminate food, causing sporadic cases of illness and disease outbreaks worldwide. For many centuries, microbial antagonism has been used in food processing to improve food safety. An understanding of the mode of action of this microbial antagonism has been gained in recent years and potential applications in food and feed safety are now being explored. This review focuses on the potential opportunities presented, and the limitations, of using microbial antagonism as a biocontrol mechanism to reduce contamination along the food chain; including animal feed as its first link. © 2014 Society of Chemical Industry     

将分数阶微分演算引入数字图像处理

为了系统论述图像分数阶微分对纹理细节的增强能力及其侧抑制原理,提出数字图像分数阶微分掩模及其运算规则。论述了分数阶微分的动力学物理意义并推导了分数阶微积分与经典时-频分析之间的关系,分析了在一定条件下二维分数阶微分的可分离性;其次,从信号处理和生物视觉神经模型两个角度提出图像分数阶微分的高斯差感受野模型,并分析其产生的特殊马赫现象;最后,提出并论述了数字图像分数阶微分掩模及其运算规则。计算机数值实验结果表明,对于纹理细节信息丰富的图像信号而言,分数阶微分对灰度变化不大的平滑区域中的纹理细节信息的增强效果明显优于整数阶微分运算。     

Discourses of the wound and desire for the Other: remembrances of the Katyń massacre and the Smoleńsk crash

ABSTRACT

We investigate the commemorative debate in Polish newspapers about how the Katyń massacre and the presidential plane crash near Smoleńsk, Russia, should be remembered. We demonstrate that a psychoanalytic discursive analysis elucidates the insistence on remembering past wounds, nationalist politics of victimhood, and the difficulties in reaching rapprochement in intercultural relations. To this end, we analyze the commemorative debates in two main Polish newspapers and a news magazine. We argue that an emotive discourse of “Katyń as a wound” yearns for a therapeutic healing of the rifts in Polish national mythology and postcommunist identity. This discourse revolves around a demand for recognition from the Russian Other of a wounded subject by employing evocative metonymies and transposing logics of equivalence and difference.     

Mycotoxins co-contamination: Methodological aspects and biological relevance of combined toxicity studies

Mycotoxins are secondary fungal metabolites produced mainly by Aspergillus, Penicillium, and Fusarium. As evidenced by large-scale surveys, humans and animals are simultaneously exposed to several mycotoxins. Simultaneous exposure could result in synergistic, additive or antagonistic effects. However, most toxicity studies addressed the effects of mycotoxins separately.

We present the experimental designs and we discuss the conclusions drawn from in vitro experiments exploring toxicological interactions of mycotoxins.

We report more than 80 publications related to mycotoxin interactions. The studies explored combinations involving the regulated groups of mycotoxins, especially aflatoxins, ochratoxins, fumonisins, zearalenone and trichothecenes, but also the “emerging” mycotoxins beauvericin and enniatins. Over 50 publications are based on the arithmetic model of additivity. Few studies used the factorial designs or the theoretical biology-based models of additivity. The latter approaches are gaining increased attention. These analyses allow determination of the type of interaction and, optionally, its magnitude. The type of interaction reported for mycotoxin combinations depended on several factors, in particular cell models and the tested dose ranges. However, synergy among Fusarium toxins was highlighted in several studies. This review indicates that well-addressed in vitro studies remain valuable tools for the screening of interactive potential in mycotoxin mixtures.     

半夏软腐病内生拮抗放线菌的分离与鉴定

针对半夏生产过程中软腐病废水普遍和危害严重的现状,从7个半夏主产区的半夏植株上分离到47个内生放线菌,通过平板和组培苗拮抗活性筛选获得两个具有较强活性的菌株07JX3-2和07JX3-7,经形态、培养特征和生理生化实验鉴定,初步确定两个分离物均属于链霉菌属(streptomyces),至于其所在种有待进一步鉴定。两个拮抗菌株的获得为半夏软腐病的生物防治研究和应用奠定了基础。     

Accumulation of dead cells from contact killing facilitates coexistence in bacterial biofilms

Bacterial communities are governed by a wide variety of social interactions, some of which are antagonistic with potential significance for bacterial warfare. Several antagonistic mechanisms, such as killing via the type VI secretion system (T6SS), require killer cells to directly contact target cells. The T6SS is hypothesized to be a highly potent weapon, capable of facilitating the invasion and defence of bacterial populations. However, we find that the efficacy of contact killing is severely limited by the material consequences of cell death. Through experiments with Vibrio cholerae strains that kill via the T6SS, we show that dead cell debris quickly accumulates at the interface that forms between competing strains, preventing physical contact and thus preventing killing. While previous experiments have shown that T6SS killing can reduce a population of target cells by as much as 10⁶-fold, we find that, as a result of the formation of dead cell debris barriers, the impact of contact killing depends sensitively on the initial concentration of killer cells. Killer cells are incapable of invading or eliminating competitors on a community level. Instead, bacterial warfare itself can facilitate coexistence between nominally antagonistic strains. While a variety of defensive strategies against microbial warfare exist, the material consequences of cell death provide target cells with their first line of defence.     

新型紫外探测器及其应用

综述了我所研制的新型紫外探测器的工作原理、结构设计。介绍了这类具有极高灵敏度和超快时间响应探测器的主要技术性能及其在高技术武器装备和民用市场的潜在应用。     

关于对当前营养问题的探讨

人们对食物由“量”的满足转向“质”的重视,渴望食以健为先。而有些人由原来渴望“三高”食品变成了要求“三低一高”食品而走进了食品营养的误区。按照营养学理论“营养”和“营养素”是两个概念。营养素之间也有相互作用和相互制约关系即营养素之间的转化作用、协同作用、拮抗作用。