Photocatalytic oxidation for antimicrobial control in built environment: A brief literature overview

This paper presents a literature review of the status of research on indoor antimicrobial control by photocatalytic oxidation (PCO). The review and discussion concentrate on (a) the PCO disinfection mechanisms; (b) different kinetic experiments and models; (c) the dependence of inactivation rate on some key influencing factors; (d) an overview of various PCO reactors and their application performance reported in the literature. Major conclusions of the overview and recommendations for future work include (a) several reaction pathways of PCO antimicrobial process were reported, but the decomposition of cell after inactivation needs to be fully understood; (b) kinetic experiments were carried out to determine the dependence of antimicrobial reaction rate on some influencing factors. However, the results from different researchers were not comparable to each other, due to differences of reaction parameters and the empirical models used; (c) various types of reactors were adopted to determine the efficiency of PCO on the rate of biological aerosol removal from air flow. There is a need to develop an empirical model for PCO reactor combining the particle dynamics and photocatalytic oxidation for bioaerosols; (d) there is a need to develop more stable and reliable photocatalysts, and further develop performance assessment protocol in both laboratory and the field.     

CD28-deficient mice are highly resistant to collagen-induced arthritis

OBJECTIVES: The understanding of testicular histology in acquired immunodeficiency syndrome (AIDS) is essential, because the sexual route is one of the main means of transmission of the human immunodeficiency virus, which is localized primarily in the germ cells of the testes. It is important to determine whether any changes have occurred in the testicular histologic patterns in the course of the AIDS epidemic. METHODS: One hundred forty testicular specimens were available from AIDS autopsies during the AIDS epidemic (1981 to 1998). The epidemic was divided into pre-zidovudine (pre-AZT) therapy (1981 to 1987) and antiviral therapy (1988 to 1998) periods; the latter period was further subdivided on the basis of the particular treatment used. Testicular histology was evaluated and correlated with patient age, CD4 T-cell counts, and pathologic findings in other parts of the body. RESULTS: Testicular histologic findings were categorized into three groups: hypospermatogenesis (group S), spermatogenic arrest (group A), and Sertoli cell only (group O). The percentage of AIDS patients with group S histologic findings remained constant throughout the study period: 26% in the pre-AZT and 28% in the antiviral therapy periods. However, there was a reversal in the percentages of patients in groups A and O: group A decreased from 48% (pre-AZT) to 28% (antiviral) and group O increased from 26% (pre-AZT) to 44% (antiviral). There was no correlation between testicular histologic results and patient age or CD4 count. Opportunistic infections and testicular neoplasms were also identified. CONCLUSIONS: This study demonstrates that current therapy and prolongation of survival in AIDS patients are associated with a shift in the histologic findings of testes toward a more pronounced loss of germ cells. However, 28% of patients still show significant spermatogenesis at the time of death from AIDS and this subgroup cannot be identified by age or CD4 T-cell counts. The presence of large numbers of residual germ cells in these patients suggests that they may continue to be infectious throughout their disease course.     

Structure,Biosynthesis, and Biological Activity of Succinylated Forms of Bacteriocin BacSp222

BacSp222 is a multifunctional peptide produced by Staphylococcus pseudintermedius 222. This 50-amino acid long peptide belongs to subclass IId of bacteriocins and forms a four-helix bundle molecule. In addition to bactericidal functions, BacSp222 possesses also features of a virulence factor, manifested in immunomodulatory and cytotoxic activities toward eukaryotic cells. In the present study, we demonstrate that BacSp222 is produced in several post-translationally modified forms, succinylated at the ε-amino group of lysine residues. Such modifications have not been previously described for any bacteriocins. NMR and circular dichroism spectroscopy studies have shown that the modifications do not alter the spatial structure of the peptide. At the same time, succinylation significantly diminishes its bactericidal and cytotoxic potential. We demonstrate that the modification of the bacteriocin is an effect of non-enzymatic reaction with a highly reactive intracellular metabolite, i.e., succinyl-coenzyme A. The production of succinylated forms of the bacteriocin depends on environmental factors and on the access of bacteria to nutrients. Our study indicates that the production of succinylated forms of bacteriocin occurs in response to the changing environment, protects producer cells against the autotoxicity of the excreted peptide, and limits the pathogenicity of the strain.     

Microfluidic devices harboring unsealed reactors for real-time isothermal helicase-dependent amplification

High-throughput microchip devices used for nucleic-acid amplification require sealed reactors. This is to prevent evaporative loss of the amplification mixture and cross-contamination, which may occur among fluidically connected reactors. In most high-throughput nucleic-acid amplification devices, reactor sealing is achieved by microvalves. Additionally, these devices require micropumps to distribute amplification mixture into an array of reactors, thereby increasing the device cost, and adding complexity to the chip fabrication and operation processes. To overcome these limitations, we report microfluidic devices harboring open (unsealed) reactors in conjunction with a single-step capillary based flow scheme for sequential distribution of amplification mixture into an array of reactors. Concern about evaporative loss in unsealed reactors have been addressed by optimized reactor design, smooth internal reactor surfaces, and incorporation of a localized heating scheme for the reactors, in which isothermal, real-time helicase-dependent amplification (HDA) was performed.     

Magneto-Memristive Switching in a 2D Layer Antiferromagnet

Memristive devices whose resistance can be hysteretically switched by electric field or current are intensely pursued both for fundamental interest as well as potential applications in neuromorphic computing and phase-change memory. When the underlying material exhibits additional charge or spin order, the resistive states can be directly coupled, further allowing electrical control of the collective phases. The observation of abrupt, memristive switching of tunneling current in nanoscale junctions of ultrathin CrI₃, a natural layer antiferromagnet, is reported here. The coupling to spin order enables both tuning of the resistance hysteresis by magnetic field and electric-field switching of magnetization even in multilayer samples.     

Relation-aware volume exploration pipeline

Volume exploration is an important issue in scientific visualization. Research on volume exploration has been focused on revealing hidden structures in volumetric data. While the information of individual structures or features is useful in practice, spatial relations between structures are also important in many applications and can provide further insights into the data. In this paper, we systematically study the extraction, representation, exploration, and visualization of spatial relations in volumetric data and propose a novel relation-aware visualization pipeline for volume exploration. In our pipeline, various relations in the volume are first defined and measured using region connection calculus (RCC) and then represented using a graph interface called relation graph. With RCC and the relation graph, relation query and interactive exploration can be conducted in a comprehensive and intuitive way. The visualization process is further assisted with relation-revealing viewpoint selection and color and opacity enhancement. We also introduce a quality assessment scheme which evaluates the perception of spatial relations in the rendered images. Experiments on various datasets demonstrate the practical use of our system in exploratory visualization.     

封装测试后序先发

封装测试传统上是看作后工序制造,可是随着半导体产业的发展,以满足消费者要求更小、更轻、更高及更多性能的电子产品,封装须与硅芯片研发及实际应用同步进行;甚或在手机等便携产品领域,封装测试要走在前列,才更能配合市场的发展需求。安森美半导体将与大家分享这封装测试发展的新思维,并希望能为封装测试产业作为中国整体半导体产业的发展取得更大的政策支持。     

Removal of co-present chromate and arsenate by zero-valent iron in groundwater with humic acid and bicarbonate

The interactions of co-present Cr(VI) and As(V), and the influences of humic acid and bicarbonate in the process of Cr(VI) and As(V) removal by Fe⁰ were investigated in a batch setting using simulated groundwater with 5 mM NaCl, 1 mM Na₂SO₄, and 0.8 mM CaCl₂ as background electrolytes at an initial pH value of 7. Cr(VI) and As(V) were observed to be subject to different impacts induced by co-existing As(V) or Cr(VI), humic acid and bicarbonate, originating from their distinct removal mechanisms by Fe⁰. Cr(VI) removal is a reduction-dominated process, whereas As(V) removal principally involves adsorption onto iron corrosion products. Experimental results showed that Cr(VI) removal was not affected by the presence of As(V) and humic acid. However, As(V) removal appeared to be inhibited by co-present Cr(VI). When the Cr(VI) concentration was 2, 5, and 10 mg/L, in the absence of humic acid and bicarbonate, As(V) removal rate constants were decreased by 27.9%, 49.0%, and 61.2%, respectively, which probably resulted from competition between Cr(VI) and As(V) for adsorption sites of the iron corrosion products. Furthermore, the presence of humic acid significantly varied As(V) removal kinetics by delaying the formation and aggregation of iron hydroxides due to the formation of soluble Fe-humate complexes and stably dispersed fine iron hydroxides colloids. In the presence of bicarbonate, both Cr(VI) and As(V) removal was increased and the inhibitory effect of Cr(VI) on As(V) removal was suppressed, resulting from the buffering effects and the promoted iron corrosion induced by bicarbonate, and the formation of CaCO₃ in solution, which enhanced As(V) adsorption.     

Evidence for the presence of different alpha-1-proteinase inhibitor genes products in mouse plasma

The plasma alpha-1-proteinase inhibitor (API) of three mouse species Mus domesticus, M. caroli and M. pahori was isolated. Each of the species isoforms were then separated by chromatofocusing; however, no significant differences in association rate constants toward human neutrophil elastase and bovine chymotrypsin were observed. The amino-acid sequence of the P'1-P'15 C-terminal fragments of the API variants indicate that mouse plasma contains at least two different active API isoforms in the case of M. domesticus (five API genes) but only one active API isoform in M. pahori and M. caroli (one API gene).