Thermal studies on electrodeposited black oxide coating on magnesium alloys

Thermal behavior of black anodic coatings on magnesium alloy, AZ31B and magnesium lithium alloy, MLA 9 has been investigated. The chemical nature of coating is characterized by infrared spectral studies. The thermoanalytical investigations have been carried out using thermogravimetry (TG), derivative thermogravimetry (DTG), and differential scanning calorimetry (DSC). The decomposition proceeds through three steps viz., dehydration, decomposition of chromium hydroxide and sulphate and decomposition of magnesium chromate to oxide. Measurement of hemispherical emittance of coatings verses temperature was investigated using calorimetric methods. The studies revealed that the thermal emittance of coatings increases with temperature. © 2001 Elsevier Science B.V

A15 superconductors: An alternative to niobium for RF cavities

Since the international committee for future accelerators recommended that the linear collider design should be based on the superconducting technology, the scientific world interest is now focused on further developments of new resonant cavities fabrication technics and cost reduction. Besides the attempt to improve the Nb sputtered on Cu accelerating structures performances, it is important to pursue research on new materials. The goal will be the achievement of superconducting cavities working better than the Nb ones at 4.2 K. Among the possible candidates, A15 compounds appear to be the most promising. Three of them were chosen: Mo–Re system which shows the A15 phase far from the stoichiometric composition (Mo3Re), V3Si that has a really high RRR value, Nb3Sn that is the only A15 compound already used for a resonant accelerating structure [G. Muller, P. Kneisel, D. Mansen, H. Piel, J. Pouryamout, R.W. Roeth, in: Proceedings of the 5th EPAC, London, 1985, p. 2085] and we obtained some interesting preliminary results. We are setting up a 6 GHz cavities measurement system: it is very simple, fast to use and it will give us the opportunity to make such small resonators become our samples

Linking activity and function to ecosystem dynamics in a coastal bacterioplankton community

For bacterial communities containing hundreds to thousands of distinct populations, connecting functional processes and environmental dynamics at high taxonomic resolution has remained challenging. Here we use the expression of ribosomal proteins (%RP) as a proxy for in situ activity of 200 taxa within 20 metatranscriptomic samples in a coastal ocean time series encompassing both seasonal variability and diel dynamics. %RP patterns grouped the taxa into seven activity clusters with distinct profiles in functional gene expression and correlations with environmental gradients. Clusters 1-3 had their highest potential activity in the winter and fall, and included some of the most active taxa, while Clusters 4-7 had their highest potential activity in the spring and summer. Cluster 1 taxa were characterized by gene expression for motility and complex carbohydrate degradation (dominated by Gammaproteobacteria and Bacteroidetes), and Cluster 2 taxa by transcription of genes for amino acid and aromatic compound metabolism and aerobic anoxygenic phototrophy (Roseobacter). Other activity clusters were enriched in transcripts for proteorhodopsin and methylotrophy (Cluster 4; SAR11 and methylotrophs), photosynthesis and attachment (Clusters 5 and 7; Synechococcus, picoeukaryotes, Verucomicrobia, and Planctomycetes), and sulfur oxidation (Cluster 7; Gammaproteobacteria). The seasonal patterns in activity were overlain, and sometimes obscured, by large differences in %RP over shorter day-night timescales. Seventy-eight taxa, many of them heterotrophs, had a higher %RP activity index during the day than night, indicating a strong diel activity rhythm at this coastal site. Emerging from these taxonomically-and time-resolved estimates of in situ microbial activity are predictions of specific ecological groupings of microbial taxa in a dynamic coastal environment

Methicillin Resistant Staphylococcus aureus Contamination of Hands and Mobile Phones of Health Care Workers in a Health Care Setting: A Silent Threat

Background: The extensive use of mobile phones in the hospital among health care workers (HCWs) can lead to infectious agents being transferred from one patient to another and thus serve as a vehicle in the transmission of nosocomial pathogens. Objectives: This study aimed to investigate the prevalence of Methicillin Resistant Staphylococcus auerus (MRSA) contamination of mobile phones and hands of HCWs in Gandaki Medical College and Teaching Hospital. Methods: The present study was hospital and laboratory based cross-sectional study, carried out from April, 2017 to December, 2017. A total of 100 mobile phone swab and 100 hand swab samples of HCWs were collected and cultured directly on MacConkey agar, blood agar, and mannitol salt agar after 24 hrs of enrichment. All the isolated organisms including MRSA were identified using standard microbiological techniques and subjected to antibiotic susceptibility testing using disc diffusion technique. Results: Among the Gram positive isolates, frequency distribution from mobile phones showed the highest prevalence of coagulase negative Staphylococci (CONS) (34.69%), followed by Staphylococcus aureus (20.41%), Bacillus spp (15.31%), Micrococci spp (11.23%), however considerable number of Diptheroides (8.16%), Enterococci (6.12%) and Streptococcus pneumoniae (4.08%). Siimilarly from hand swabs CONS (39.62%), followed by S. aureus (26.42%), Bacillus spp (10.38%), Micrococci (11.32%), Enterococci (6.60%) and Diptheroids (5.66%) were isolated. The frequency of MRSA was 20%, 25% among mobile phones and hands of HCWs respectively. Drugs like Vancomycin, Amikacin, Clindamycin and Gentamycin were found quite effective against S. aureus in the present study and would be better options for the management of such infections. Conclusions: Mobile phones and hands of HCWs were the potential source of nosocomial infections including multidrug-resistant pathogens like methicillin-resistant S. aureus

Synthesis, characterization, and preclinical validation of a PET radiopharmaceutical for interrogating Aβ (β-amyloid) plaques in Alzheimer’s disease

BACKGROUND: PET radiopharmaceuticals capable of imaging β-amyloid (Aβ) plaque burden in the brain could offer highly valuable diagnostic tools for clinical studies of Alzheimer’s disease. To further supplement existing armamentarium of FDA-approved agents as well as those under development, and to correlate multiphoton-imaging data reported earlier, herein, we describe preclinical validation of a PET tracer. METHODS: A novel PET radiopharmaceutical ((18)F-7B) was synthesized and characterized. To assess its affinity for Aβ, binding assays with Aβ(1-42) fibrils, Alzheimer’s disease (AD) homogenates, and autoradiography studies and their IHC correlations were performed. For assessing its overall pharmacokinetic profiles in general and its ability to cross the blood-brain barrier (BBB) in particular, biodistribution studies in normal mice were performed. Finally, for evaluating potential for (18)F-7B to serve as a targeted Aβ probe, the microPET/CT imaging was performed in age-matched amyloid precursor protein/presenilin-1 (APP/PS1) mice and wild-type (WT) counterparts. RESULTS: The radiotracer (18)F-7B shows saturable binding to autopsy-confirmed AD homogenates (K(d) = 17.7 nM) and Aβ(1-42) fibrils (K(d) = 61 nM). Preliminary autoradiography studies show binding of (18)F-7B to cortical Aβ plaques in autopsy-confirmed AD tissue sections, inhibition of that binding by unlabeled counterpart 7A-indicating specificity, and a good correlation of tracer binding with Aβ immunostaining. The agent indicates high initial penetration into brains (7.23 ± 0.47%ID/g; 5 min) of normal mice, thus indicating a 5-min/120-min brain uptake clearance ratio of 4.7, a benchmark value (>4) consistent with the ability of agents to traverse the BBB to enable PET brain imaging. Additionally, (18)F-7B demonstrates the presence of parental species in human serum. Preliminary microPET/CT imaging demonstrates significantly higher retention of (18)F-7B in brains of transgenic mice compared with their WT counterparts, consistent with expected binding of the radiotracer to Aβ plaques, present in APP/PS1 mice, compared with their age-matched WT counterparts lacking those Aβ aggregates. CONCLUSIONS: These data offer a platform scaffold conducive to further optimization for developing new PET tracers to study Aβ pathophysiology in vitro and in vivo

Mechanical versus thermodynamical melting in pressure-induced amorphization: the role of defects

We study numerically an atomistic model which is shown to exhibit a one--step crystal--to--amorphous transition upon decompression. The amorphous phase cannot be distinguished from the one obtained by quenching from the melt. For a perfectly crystalline starting sample, the transition occurs at a pressure at which a shear phonon mode destabilizes, and triggers a cascade process leading to the amorphous state. When defects are present, the nucleation barrier is greatly reduced and the transformation occurs very close to the extrapolation of the melting line to low temperatures. In this last case, the transition is not anticipated by the softening of any phonon mode. Our observations reconcile different claims in the literature about the underlying mechanism of pressure amorphization.Comment: 7 pages, 7 figure

Apigenin inhibits PMA-induced expression of pro-inflammatory cytokines and AP-1 factors in A549 cells

Acute and chronic alveolar or bronchial inflammation is thought to be central to the pathogenesis of many respiratory disorders. Cytokines and granulocyte macrophage colony-stimulating factors (GM-CSF) play an important role in chronic inflammation. Activator protein-1 (AP-1) the superfamily of transcription factors is involved in proliferation, differentiation, apoptosis, and transformation including inflammation. Understanding the function and regulation of proinflammatory factors involved in inflammation may provide the novel therapeutic strategies in the treatment of inflammatory diseases. Our aim of the present study is to investigate the pro-inflammatory cytokines and pattern of AP-1 factors expressed during activation of lung adenocarcinoma A549 cells by Phorbol-12-myristate-13-acetate (PMA) and to understand the anti-inflammatory effect of apigenin. A549 cells were treated with and without PMA or apigenin, and the cell viability was assessed by MTT assay. Expressions of inflammatory mediators and different AP-1 factors were analyzed by semi-quantitative RT-PCR. IL-6 protein secreted was analyzed by ELISA, and expressions of IL-1β, c-Jun, and c-Fos proteins were analyzed by Western blotting. Activation of A549 cells by PMA, induced the expression of pro-inflammatory cytokine (IL-1β, IL-2, IL-6, IL-8, and TNF-α) mRNAs and secretion of IL-6 and the expression of specific AP-1 factors (c-Jun, c-Fos, and Fra-1). Treatment of cells with apigenin, significantly inhibited PMA-stimulated mRNA expression of above pro-inflammatory cytokines, AP-1 factors, cyclooxygenase-2, and secretion of IL-6 protein. Results suggested that the AP-1 factors may be involved in inflammation and apigenin has anti-inflammatory effect, which may be useful for therapeutic management of lung inflammatory diseases. © 2015, Springer Science+Business Media New York

Architecture for a territorial dispute resolution system : a systems approach

Thesis (S.M.)--Massachusetts Institute of Technology, System Design and Management Program, 2007.Includes bibliographical references (leaves 137-139).Introduction: A great part of the world today is engaged in excruciating conflicts that threaten the afflicted regions locally besides holding global peace to ransom. Most of these conflicts take the form of territorial disputes that are often protracted and sap the energies out of the nation states. Kashmir, Sudan, Israel-Palestine and Sri-Lanka today are embroiled in a bitter dispute embittered by relentless bloodshed and deep-rooted animosity carried forward through generations. The disputed regions in themselves are a mute testimony of the abject neglect of its subjects by the central ruling body (could be a democratic government! a dictator or a monarch) and failure to provide some of the important political goods across the board for a long period of time. When weighed against some of the accepted norms of development indices like the GINI index, GDP, GDP per capita, infant mortality rates, HDI index, TI index, etc one would see that the disputed regions perform quite pathetically across most of the metrics and not without a reason. Nation states exist to provide political goods to people (Ref 1). However, quite unabashedly nation-states continue its tirade against each other over a piece of land pumping huge sums of public assets that could otherwise be diverted towards development efforts depressing benefits in both the disputed territory and on the whole. Territoriality is dogma that invokes strong reactions. As per Zartman (Ref 2) a state's territory is a collective good that is equally shared by the citizens of the state. This means that the territory is indivisible and is available in the same proportion to all the citizens. It is considered to be one of the three basic components--together with people and a government--which endow a state with a sovereign moral personality universally recognized by the law and the community of nations. Till the time the territoriality is perceived as a collective good, there is no room for territorial claims to erupt. They however occur when the "national territory"--or, what the state's authorities suppose to be the "national territory"--is no longer perceived as a common good by a concerned group of citizens and becomes a "need" for this specific group. Territorial claims are about the desacralization of this territorial absoluteness. They represent iconoclastic uprisings from "politically active communal groups" determined to question the absolutely sacred dogma of the state's territorial integrity. Thus fundamentally a territorial dispute is a process of deconstruction and de-institutionalization of the nation state's order and boundaries. The focus of this thesis is to understand the epistemology of a territorial dispute and develop a framework for creating a more effective conflict resolution design. This by no means is aimed at churning out a cook book kind of a recipe to solve all the territorial disputes that afflict the world. On the contrary, this work makes an attempt to trace the path as we move from a dispute system to a resolution system by understanding the underlYing architecture. It is in fact akin to taking a step backwards and revisiting the delicate theme of territorial disputes by dissecting it deeper to peel off the layers that wrap the core problem. We use the principles of systems thinking and system architecture in understanding the intrinsic nature of a territorial dispute by treating it as a system operating in a given environment. The systems thinking paradigm allows us to view the problem in an unbiased and objective manner without getting fixated on a particular solution or a problem area. It attempts to view the conflict holistically and tries to lay threadbare the embedded structural units in the system by decomposing it into its lowest entity. The objectivity that would (in all likelihood) emerge from such an exercise may provide plausible steps to architect a resolution system design template or at least strengthen the intuitive logic of the negotiators and mediators as they grapple with the specter of a territorial dispute. In taking this view on the issue, it is indeed quite well understood that architecture of systems that are laced with social and political processes is tedious as they are highly complex and non-linear in their response. The complexity stems from the deep crosscoupling between the social, political and economic processes and the non- linearity arises out of the fact that each input in a particular realm does not necessarily elicit a proportional response. There are strong causal feedback loops that make the system response counter-intuitive too. It is beyond doubt, a sizeable challenge for a resolution system architect to pick up the gauntlet and create a simple yet creative architecture that would form the vertebral column for the design of a robust resolution system. To be able to do so one needs to clearly understand the rudiments of Systems Architecture and International Relations so as to weave a concept together.by Rajeev Sharma.S.M

EISMF

Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 124-130).There are several technological solutions available in the market to help organizations with information security breach detection and prevention such as intrusion detection and prevention systems, antivirus software, firewalls, and spam filters. There is no doubt in the fact that significant progress has been made in the technological side of information security. However, when we study causes of information security breaches, we find that a significant number are caused by non-technical reasons such as social engineering, theft of computing device or portable hard drive, human behavior, and human error. This leads us to conclude that information security should not be viewed through technology perspective only. Instead, a more holistic approach is required. This thesis provides a systems approach towards information security management and include technological, management and social aspects. This thesis starts with introduction especially background and motivation of the author, followed by literature research. Next, Enterprise Information Security Management Framework is presented leading to estimation of an organization's information security management maturity-level. Finally, conclusion and potential future work are presented.by Dhirendra Sharma.S.M.in Engineering and Managemen