流式细胞仪在海洋无脊椎动物细胞学研究中的应用

简要概述了流式细胞仪的工作原理以及在海洋动物细胞学研究中流式细胞仪的应用。包括对海洋动物主要是无脊椎动物血细胞的分类及其功能的研究和海洋无脊椎动物多倍体育种中染色体倍性检测等。     

Steroid hormone receptors, matrix metalloproteinases, insulin-like growth factor, and dystroglycans interactions in prostatic diseases in the elderly men

OBJECTIVES: The aim of this study was to evaluate the reactivity of steroid hormone receptors (SHRs), dystroglycans (DGs), matrix metalloproteinases (MMPs), insulin‐like growth factor receptor (IGFR‐1), and laminin (Lam) in both prostatic stromal and epithelial compartments showing different diseases in elderly men. METHODS: Sixty prostatic samples were obtained from 60‐ to 90‐year‐old patients (mean 63 years) with and without prostatic lesions from Hospital of the School of Medicine, State University of Campinas (UNICAMP). The Samples were divided into standard (no lesions); high grade prostatic intraepithelial neoplasia (HGPIN); prostatic cancer (PC); and benign prostatic hyperplasia (BPH) groups. The samples were submitted to immunohistochemistry and Western blotting analyses. Research Ethics Committee of the School of Medicine, University of Campinas/UNICAMP (number 0094.0.146.000‐08). RESULTS: The results showed increased IGFR‐1 and MMPs protein levels in the PC and HGPIN groups. Decreased αDG and βDG protein levels were verified in the PC and HGPIN groups. Androgen receptor (AR) reactivity was similar among all groups. Estrogen receptor α (Erα) immunoreactivity was more intense in the epithelium in the PC and HGPIN groups. Estrogen receptor β (ERβ) immunoreactivity was weak in the epithelium of the HGPIN and PC groups. CONCLUSIONS: To conclude, there was an association among IGFR‐1, MMPs, and SHRs, indicating IGFR‐1 as a target molecule in prostate therapy, considering the IGF proliferative properties. Also, the distinct SHRs reactivities in the lesions in both prostatic compartments indicated different paracrine signals and pointed out the importance of estrogenic pathways in the activation of these disorders. Microsc. Res. Tech. 75:1197–1205, 2012. © 2012 Wiley Periodicals, Inc.     

Erosion-corrosion interactions and their effect on marine and offshore materials

Increasingly the demands of modern fluid handling systems are for low costs with increased reliability and longevity along with no loss of fluid containment. These cannot be achieved without minimising the material damage caused by the combined surface degradation mechanisms of erosion and corrosion when systems are handling solids or are cavitating. This paper reviews the rationale behind the selection of erosion resistance surfaces for fluid handling equipment and highlights the complexities encountered when these surfaces are exposed to environments which contain sand particles or cavitation in a corrosive medium. The erosion and erosion-corrosion performance of a variety of coatings and bulk surfaces are discussed using volume loss rate versus sand impact energy maps. Synergistic terms are identified using standard deviation ratios of electrochemical current noise. Recent researches on the erosion-corrosion of coatings of aluminium, cermets and nickel aluminium bronze are reviewed as candidates for erosion-corrosion resistant surfaces. Electrochemical techniques designed to monitor the erosion-corrosion mechanisms and coating integrity are used to quantify the synergistic terms present when both erosion and corrosion act simultaneously.     

Grid-specimen interactions: factors affecting copper nanocluster formation on polymer thin films

All transmission electron microscopy (TEM) studies require the use of grids to support thin films or sections of specimens within the microscope. These grids are presumed to remain inert during sample loading and analysis, an assumption which becomes questionable when on-the-grid processing methods are employed to probe the response of a specimen to a particular stimulus, such as temperature increase. Uniform dispersions of nanoclusters were observed to develop on and undergo chemical complexation with thin cast films of a poly(siloxaneimide) copolymer supported on various copper grids during thermal annealing at temperatures of up to 200°C. The thermal conditions which promoted nanocluster formation were investigated. Experiments designed to elucidate the mechanism by which these nanoclusters develop revealed that cuprous oxide (Cu₂O) from the copper support grids is deposited on these imide-bearing films from the vapour phase.     

Protein-mediated interactions in the dynamic regulation of acute inflammation

Protein-mediated interactions are the fundamental mechanism through which cells regulate health and disease. These interactions require physical contact between proteins and their respective targets of interest. These targets include not only other proteins but also nucleic acids and other important molecules as well. These proteins are often involved in multibody complexes that work dynamically to regulate cellular health and function. Various techniques have been adapted to study these important interactions, such as affinity-based assays, mass spectrometry, and fluorescent detection. The application of these techniques has led to a greater understanding of how protein interactions are responsible for both the instigation and resolution of acute inflammatory diseases. These pursuits aim to provide opportunities to target specific protein interactions to alleviate acute inflammation.     

Decentralized stabilizability and formation control of multi-agent systems with antagonistic interactions

This paper studies the stabilizability and formation control problems of multi-agent systems with antagonistic interactions. The agents run a bipartite consensus protocol using a signed Laplacian which is different from the conventional one. By taking advantage of the proposed structurally balanced independent strongly connected components(SBiSCCs) of the signed graph, a sufficient and necessary condition is presented to solve the decentralized stabilizability problem of multi-agent systems with antagonistic interactions. Besides, formation control is considered and the sufficient and necessary condition is provided by applying the proposed results. Several simulations are given to illustrate the theoretical results.     

ZDDP and MoDTC interactions in boundary lubrication—The effect of temperature and ZDDP/MoDTC ratio

Tribofilms formed under boundary lubrication from ZDDP and MoDTC additives alone or in different ratios in the lubricant have been studied. The tribological performance is linked to the tribofilm properties and consequently to the lubricating conditions. Tribofilms are formed using a reciprocating pin-on-plate tribometer. Surface sensitive analytical techniques, such as energy dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS) have been used for tribofilm characterisation. The XPS peaks have been deconvoluted to characterise the species formed in the wear scar. The formation of species with different tribological properties, due to the decomposition of ZDDP and MoDTC molecules as a result of testing temperature, is shown. Surface analyses have shown that MoDTC decomposes, even in low-lubricant bulk temperature tests (30 °C), forming the same species as in high-lubricant bulk temperature tests (100 and 150 °C) but the tribofilms give different tribological performance. The effectiveness in friction reduction is shown to depend on the ratio between what are defined as high- and low-friction species in the tribofilm.     

Additive-additive and additive-surface interactions in lubrication

Combinations of additives are often found to exhibit antagonistic or synergistic effects compared to the performance of the individual additives. This paper reviews the state of knowledge concerning such effects. Direct interactions, where two additives combine at a molecular level, are distinguished from complementary or exclusary effects where the individual contributions of separate additives enhance or reduce overall performance but with no direct interaction. Additive interactions take place in solution and at surfaces, and both are discussed.     

ZDDP and MoDTC interactions and their effect on tribological performance – tribofilm characteristics and its evolution

In this work, the interactions between two key additives in current lubricants (ZDDP and MoDTC) and the effect on tribofilm formation and tribofilm evolution under boundary lubrication are studied. The chemical and tribological characteristics of the tribofilms are probed using measurement of friction, wear and film characteristics. Tribofilms have been examined by energy dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). In order to investigate the morphology of the reaction films formed, atomic force microscopy (AFM) was used. In this work, for the first time, a link between a proposed MoDTC breakdown mechanism and MoDTC tribofilm characteristics, measured on experimentally derived tribofilms, is made.     

Organelle interactions and possible degradation pathways visualized in high-pressure frozen algal cells

Organelle interactions, although essential for both anabolic and catabolic pathways in plant cells have not been examined in detail so far. In the present study the structure of different organelle–organelle, organelle–vesicle and organelle–membrane interactions were investigated in growing and nongrowing cells of the green alga Micrasterias denticulata by use of high pressure freeze fixation and energy filtering transmission electron microscopy. It became clear that contacts between mitochondria always occur by formation of a cone-shaped protuberance of one of the mitochondria which penetrates into its fusion partner. In the same way, structural interactions between mitochondria and mucilage vesicles and between microbodies and mucilage vesicles are achieved. Lytic compartments contact mitochondria or mucilage vesicles again by forming protuberances and by extending their contents into the respective compartment. Detached portions of mitochondria are found inside lytic compartments as a consequence of such interactions. Mitochondria found in contact with the plasma membrane reveal structural disintegration. Our study shows that interactions of organelles and vesicles are frequent events in Micrasterias cells of different ages. The interactive contacts between lytic compartments and organelles or vesicles suggest a degradation pathway different from autophagy processes described in the literature. Both the interactions between vesicles and organelles and the degradation pathways occur independently from cytoskeleton function as demonstrated by use of cytochalasin D and the microtubule inhibitor amiprophos-methyl.     

Electron-gas interactions in the environmental scanning electron microscopes gaseous detector

The construction of high signal-to-noise, artefact-free secondary electron images in the elevated pressure conditions of an environmental SEM is a nontrivial process. The interactions of information carrying species, as well as probe beam electrons, with the chamber gas are the major reasons for such complications. In this paper, we discuss and review the present understanding of these phenomena. In addition, we outline procedures for assessing the signal-amplifying and charge-neutralising capabilities of an environmental gas. It is only with a knowledge of such parameters and an appreciation of the gas-electron collision processes that one can optimise the microscope's operating parameters. Moreover, such information enables the separation of topographic detail from artefactual features in the detected electron images.     

Cryo‐scanning electron microscopy and light microscopy for the study of fungi interactions

The application of the cryo‐scanning electron microscopy and light microscopy for the study of the interactions at different environmental conditions between Penicillium oxalicum and Fusarium verticillioides is described. A dual microculture was developed for the light microscopy analysis of the interaction. The microscope and macroscopic examinations were compared. Analysis of Petri plates revealed that F. verticillioides was a competitor for space and nutrients while P. oxalicum was a mycoparasite under the microscopic observations. Microsc. Res. Tech., 2010. © 2010 Wiley‐Liss, Inc.     

Combining optical tweezers and scanning probe microscopy to study DNA-protein interactions

We present the first results obtained with a new instrument designed and built to study DNA-protein interactions at the single molecule level. This microscope combines optical tweezers with scanning probe microscopy and allows us to locate DNA-binding proteins on a single suspended DNA molecule. A single DNA molecule is stretched taut using the optical tweezers, while a probe is scanned along the molecule. Interaction forces between the probe and the sample are measured with the optical tweezers. The instrument thus enables us to correlate mechanical and functional properties of bound proteins with the tension within the DNA molecule. The typical friction force between a micropipette used as probe and a naked DNA molecule was found to be <1 pN. A 16 micro m DNA molecule with approximately 10-15 digoxygenin (DIG) molecules located over a 90 nm range in the middle of the DNA was used as a model system. By scanning with an antidigoxygenin (alpha-DIG) antibody-coated pipette we were able to localize these sites by exploiting the high binding affinity between this antibody-antigen pair. The estimated experimental resolution assuming an infinitesimally thin and rigid probe and a single alpha-DIG/DIG bond was 15 nm.     

Parametric study of aluminium alloy fouling in marine environment using RSM technique

ABSTRACT

Fouling is known to be a prominent industrial problem which is greatly affected by parameters like temperature, time and flowrate. The aim of this work was to simulate the fouling process in AA 6061 by developing a model through Minitab 16 and evaluate the models. Box Behnken design of Response surface methodology was applied for modelling and optimization of fouling propensity in artificial sea water. A response surface model was obtained and Analysis of Variance was performed to test the significance of the model. Fouling propensity was found in terms of weight gain. An experimental rig consisting of a recirculating loop mimicking the industrial conditions of fouling was used in the study. SEM analysis shows uneven deposits on the metal surface. Sharp, irregular deposits pressed deep into the metal was observed. The finding of this work would enable us to evaluate the individual and interactive effects of the parameters.     

Studies on additive-additive interactions: Effects of dispersant and antioxidant additives on the synergistic combination of overbased sulphonate and ZDDP

A strong synergism between overbased sulphonate (OBS) and zinc dialkyldithiophosphate (ZDDP) in a proven diesel engine oil formulation has been reported in an earlier communication.¹ In continuation of these studies, the effect of different types of dispersant, of varying nitrogen content, and an antioxidant, on a synergistic combination of OBS-ZDDP has been investigated. Both detergency and dispersancy of the optimised formulation were improved with high nitrogen-content dispersants, which also increased strongly the wear tendencies. The antioxidant, though it improved detergency, did not show any positive effect on antiwear performance. Detailed IR and ³¹p-NMR spectroscopic analyses on interactive additive pairs, namely, ZDDP-PIBS and ZDDP-antioxidant, indicated the formation of association complexes and hydrogen bonding respectively.     

Development of histamine-immunoreactivity in the Central nervous system of the two locust species Schistocerca gregaria and Locusta migratoria

Locusts are attractive model preparations for cellular investigations of neurodevelopment. In this study, we investigate the immunocytochemical localization of histamine in the developing ventral nerve cord of two locust species, Schistocerca gregaria and Locusta migratoria. Histamine is the fast neurotransmitter of photoreceptor neurons in the compound eye of insects, but it is also synthesized in interneurons of the central nervous system. In the locust ventral nerve cord, the pattern of histamine-immunoreactive neurons follows a relatively simple bauplan. The histaminergic system comprises a set of single, ascending projection neurons that are segmentally arranged in almost every neuromere. The neurons send out their axons anteriorly, forming branches and varicosities throughout the adjacent ganglia. In the suboesophageal ganglion, the cell bodies lie in a posteriolateral position. The prothoracic ganglion lacks histaminergic neurons. In the posterior ganglia of the ventral nerve cord, the somata of the histaminergic neurons are ventromedially positioned. Histamine-immunoreactivity starts around 50% of embryonic development in interneurons of the brain. Subsequently, the neurons of the more posterior ganglia of the ventral nerve cord become immunoreactive. From 60% embryonic development, the pattern of soma staining in the nerve cord appears mature. Around 65% of embryonic development, the photoreceptor cells show histamine-immunoreactivity. The histaminergic innervation of the neuropile develops from the central branches toward the periphery of the ganglia and is completed right before hatching.     

表面粗糙度产生原因及影响因素的分析与控制

分析了表面粗糙度产生的原因、影响因素以及对零件使用性能的影响,提出了控制表面粗糙度的多种方法,对机械加工技术人员具有一定的参考价值。     

Changes in friction and wear performance caused by interactions among lubricant additives

Engine oil additives generally fall into one of two general categories: those that affect bulk oil properties and those that affect the surface properties of lubricated parts. Interactions among surface-active additives can lead to less-than-expected lubricant performance. Laboratory friction and wear test results are presented to illustrate the changes in lubricant performance that interactions among additives can cause. Some possible explanations are proposed.