895 research outputs found

    Cyber Security training tools for the nuclear energy sector

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    Nowadays, cyber security should be a priority for everyone when they connect their laptop to the internet; however, not many internet users have sufficient knowledge about cyber security. A cyberattack on an individual’s computer could result in the loss of personal information, financial information, or other resources. The damage from a cyberattack on a nuclear facility or other critical infrastructure could have much greater consequences. The attackers could impact the confidentiality of data, the availability of key systems, or the integrity of those safety or operating systems. Therefore, the National Nuclear Security Administration has tasked Pacific Northwest National Laboratory with developing eLearning modules for teaching cyber security to nuclear plant personnel. The eLearning modules are designed to increase cyber security knowledge and awareness for nuclear facility decision makers, regulators, workers, and stakeholders. The modules are designed along the lines of a university curriculum with foundation courses (100 level), and more in-depth courses (200 to 400 level). In general, eLearning modules need to have many interactive activities in order to grab and maintain the learners’ attention. Storyline 2TM is used as our eLearning management system for developing and presenting eLearning content. It provides many features that allow developers to create interactive learning activities. These include drag-and-drop, timeline, and knowledge testing products; moreover, Storyline 2TM allows pictures and videos to be displayed. Content developers are able to publish their Storyline 2TM products into many different formats, including CD, Web, and Word documents. This work focuses on the development of three 200 level courses covering cyber security threats, vulnerabilities, and consequences using Storyline. Gearhead is an activity to provide information on how the adversaries steal information of the employee. Gearhead provides a full freedom to users to discover different ways of attack from adversaries, and Gearhead contains many pictures to make an activity more interesting. Introduction timeline is a product that included a narration voice and drag-and-drop activity, so users have to drag the circle along the timeline to see the picture, listen to the audio, and read the information. By the end of each topic, users will receive some type of assessment to check their knowledge, and Storyline allows to create a test bank questions that we can use for multiple question quiz and drag-and-drop activity. Using Storyline 2TM is a good tool for developing effective cyber security eLearning modules. Beyond this specific training objective this project provided an opportunity for the author to learn education software and techniques useful in modern classrooms and curriculum

    Using unmanned aerial vehicles (‘drones’) to collect data from tagged fishers in the environment

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    Fisher (Pekania pennant) belongs to the weasel family. In October 2014, the United States Fish and Wildlife Service proposed to list the West Coast Distinct Population Segment of fisher as threatened under the Endangered Species Act. We wish to better define where fishers live within their habitats and use that information to improve conservation efforts. Previously, to track the behavior of wild fishers, researchers put tracker collars on the animals and relied on networks of fixed antennas on the ground in the environment to collect data. We are experimenting with using unmanned aerial vehicles (‘drones’) to collect data from tagged fishers in the environment. Using drones could offer advantages over antennas that require a dedicated power source and are placed in the field long-term

    Predicting Tensile Strength for Prestressed Reinforced Concrete-Driven Piles

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    Reinforced concrete piles installed by impact hammers have been used as a common solution for deep foundations because they are cost effective and require less time for construction. Driven piles are often used in large volumes for infrastructure and industrial projects in rural areas. Unlike other installation methods, installing piles using impact hammers can generate tensile stress during construction, which can result in pile failures. Induced tensile stress occurs when piles are being driven through a hard soil layer to a softer soil layer, and transverse cracks happen when induced tensile stress exceeds the pile tensile strength. This issue is not explicitly stated in most standards; the rare code that mentions this issue is AASHTO 2014. AASHTO 2014 uses correlations between the concrete tensile and compressive strengths to obtain the pile tensile strength. However, data collected from more than 1300 tests on the correlations between the concrete tensile and compressive strengths show that the concrete pile tensile strengths obtained using AASHTO 2014 are significantly conservative. This paper provides an adjustment in the correlation for the tensile strength based on previous data, and it proposes an approach to estimate the tensile strength for concrete-driven piles. A case study of the effects of pile failures on the tensile strength is also presented to verify the approach. The obtained tensile strength from the proposed approach agrees well with the measured field data. For the case study, the pile tensile strength obtained using the proposed approach is 38% and 59% higher than the tensile strength obtained using AASHTO 2014. These quantities are significant but may vary, depending on the compression strength of the concrete used and the pile configurations. The proposed approach better predicts the tensile strength of concrete piles and can lead to cost savings. View Full-Tex

    The burden and characteristics of enteric fever at a healthcare facility in a densely populated area of Kathmandu

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    Enteric fever, caused by Salmonella enterica serovars Typhi and Paratyphi A (S. Typhi and S. Paratyphi A) remains a major public health problem in many settings. The disease is limited to locations with poor sanitation which facilitates the transmission of the infecting organisms. Efficacious and inexpensive vaccines are available for S. Typhi, yet are not commonly deployed to control the disease. Lack of vaccination is due partly to uncertainty of the disease burden arising from a paucity of epidemiological information in key locations. We have collected and analyzed data from 3,898 cases of blood culture-confirmed enteric fever from Patan Hospital in Lalitpur Sub-Metropolitan City (LSMC), between June 2005 and May 2009. Demographic data was available for a subset of these patients (n = 527) that were resident in LSMC and who were enrolled in trials. We show a considerable burden of enteric fever caused by S. Typhi (2,672; 68.5%) and S. Paratyphi A (1,226; 31.5%) at this Hospital over a four year period, which correlate with seasonal fluctuations in rainfall. We found that local population density was not related to incidence and we identified a focus of infections in the east of LSMC. With data from patients resident in LSMC we found that the median age of those with S. Typhi (16 years) was significantly less than S. Paratyphi A (20 years) and that males aged 15 to 25 were disproportionately infected. Our findings provide a snapshot into the epidemiological patterns of enteric fever in Kathmandu. The uneven distribution of enteric fever patients within the population suggests local variation in risk factors, such as contaminated drinking water. These findings are important for initiating a vaccination scheme and improvements in sanitation. We suggest any such intervention should be implemented throughout the LSMC area.This work was supported by The Wellcome Trust, Euston Road, London, United Kingdom. MFB is supported by the Medical Research Council (grant G0600718). SB is supported by an OAK foundation fellowship through Oxford University

    Non-zinc mediated inhibition of carbonic anhydrases: coumarins are a new class of suicide inhibitors.

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    The X-ray crystal structure of the adduct between the zinc metalloenzyme carbonic anhydrase II (CA, EC 4.2.1.1) with the recently discovered natural product coumarin derivative 6-(1S-hydroxy-3-methylbutyl)-7-methoxy-2H-chromen-2-one showed the coumarin hydrolysis product, a cis-2-hydroxy-cinnamic acid derivative, and not the parent coumarin, bound within the enzyme active site. The bound inhibitor exhibits an extended, two-arm conformation that effectively plugs the entrance to the enzyme active site with no interactions with the catalytically crucial zinc ion. The inhibitor is sandwiched between Phe131, with which it makes an edge-to-face stacking, and Asn67/Glu238sym, with which it makes several polar and hydrogen bonding interactions. This unusual binding mode, with no interactions between the inhibitor molecule and the active site metal ion is previously unobserved for this enzyme class and presents a new opportunity for future drug design campaigns to target a mode of inhibition that differs substantially from classical inhibitors such as the clinically used sulfonamides and sulfamates. Several structurally simple coumarin scaffolds were also shown to inhibit all 13 catalytically active mammalian CA isoforms, with inhibition constants ranging from nanomolar to millimolar. The inhibition is time dependent, with maximum inhibition being observed after 6 h.No Full Tex

    ẢNH HƯỞNG CỦA MÔI TRƯỜNG NUÔI CẤY LÊN SINH TRƯỞNG CỦA CALLUS CÂY GIẢO CỔ LAM (Gynostemma pentaphyllum (Thunb.) Makino) – MỘT CÂY DƯỢC LIỆU CÓ GIÁ TRỊ

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    Gynostemma pentaphyllum (Thunb.) Makino (Jiaogulan) is a traditional medicinal herb belonging to the Cucurbitaceae family. G. pentaphyllum grows widely in Southern China, Japan, Korea, and Vietnam. The essential bioactive components of Jiaogulan are saponin glycosides (gypenosides) and antioxidants. Jiaogulan exhibits bioactive activities such as anticancer, antioxidant, cholesterol-reducing agent, immunopotentiation, and others. In this study, the primary callus of Jiaogulan was used as a material to evaluate the influence of the culture medium on the induction and growth of secondary calli. The results reveal that the callus cultured on the MS medium supplemented with 2.0 mg/L kinetin and 0.5 mg/L indole-3-butyric acid has the best growth ability, high rate of secondary callus induction (100%), and good callus quality for suspension culture. The concentration of gypenoside and Rb1 in callus is 36.298 and 0.009 mg/g dry weight. The gypenoside concentration of callus is lower than that of leaves (65.58%) and almost similar to that of stems (92.38%) from natural samples. The suitable solvent for the extraction of gypenoside is methanol. The obtained callus will be used as material for cell suspension culture in further studies.Giảo cổ lam (Gynostemma pentaphyllum (Thunb.) Makino) là một cây thuốc dân gian thuộc họ Bầu bí. Cây phân bố rộng ở miền Nam Trung Quốc, Nhật Bản, Hàn Quốc và Việt Nam. Các thành phần có hoạt tính sinh học quan trọng của Giảo cổ làm là saponin glycoside (gypenoside) và các chất chống oxy hóa. Giảo cổ lam được sử dụng hỗ trợ chống ung thư, chống oxy hóa, giảm cholesterol, tăng cường miễn dịch và các tác dụng khác. Trong nghiên cứu này, callus sơ cấp của cây Giảo cổ lam được sử dụng làm nguyên liệu để đánh giá ảnh hưởng của môi trường nuôi cấy lên khả năng phát sinh và sinh trưởng của callus thứ cấp. Kết quả cho thấy, callus được nuôi cấy trên môi trường MS có bổ sung 2,0 mg/L kinetin và 0,5 mg/L indole-3-butyric acid sinh trưởng tốt nhất; tỷ lệ tạo callus thứ cấp cao (100%); callus đáp ứng được tiêu chuẩn để nuôi cấy huyền phù. Hàm lượng gypenoside và Rb1 trong callus là 36,298 và 0,009 mg/g chất khô; gypenoside thấp hơn trong lá (65,58%) và gần tương đương với mẫu thân (92,38%) của sản phẩm thu mua từ thị trường. Dung môi thích hợp để tách chiết gypenoside là methanol. Callus thu được sẽ được sử dụng làm nguyên liệu cho nuôi cấy tế bào huyền phù trong các nghiên cứu tiếp theo

    Cyclic-di-AMP synthesis by the diadenylate cyclase CdaA is modulated by the peptidoglycan biosynthesis enzyme GlmM in lactococcus lactis

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    © 2016 John Wiley & Sons Ltd. The second messenger cyclic-di-adenosine monophosphate (c-di-AMP) plays important roles in growth, virulence, cell wall homeostasis, potassium transport and affects resistance to antibiotics, heat and osmotic stress. Most Firmicutes contain only one c-di-AMP synthesizing diadenylate cyclase (CdaA); however, little is known about signals and effectors controlling CdaA activity and c-di-AMP levels. In this study, a genetic screen was employed to identify components which affect the c-di-AMP level in Lactococcus. We characterized suppressor mutations that restored osmoresistance to spontaneous c-di-AMP phosphodiesterase gdpP mutants, which contain high c-di-AMP levels. Loss-of-function and gain-of-function mutations were identified in the cdaA and gdpP genes, respectively, which led to lower c-di-AMP levels. A mutation was also identified in the phosphoglucosamine mutase gene glmM, which is commonly located within the cdaA operon in bacteria. The glmM I154F mutation resulted in a lowering of the c-di-AMP level and a reduction in the key peptidoglycan precursor UDP-N-acetylglucosamine in L. lactis. C-di-AMP synthesis by CdaA was shown to be inhibited by GlmMI154F more than GlmM and GlmMI154F was found to bind more strongly to CdaA than GlmM. These findings identify GlmM as a c-di-AMP level modulating protein and provide a direct connection between c-di-AMP synthesis and peptidoglycan biosynthesis. c-di-AMP is an essential signalling molecule which affects peptidoglycan homeostasis and resistance against various stressors, however little is known regarding how the c-di-AMP level is regulated in the cell. Here we identify the peptidoglycan biosynthesis enzyme GlmM as a modulator of c-di-AMP synthesis through its regulation of diadenylate cyclase enzyme CdaA activity in Lactococcus lactis

    Insight into the effect of zinc oxide nanoparticles coated multi-walled carbon nanotubes (ZnO/MWCNTs) on the thermal conductivity of epoxy nanocomposite as an electrical-insulating coating

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    The effect of zinc oxide (ZnO) nanoparticles on the thermal conductivity of zinc oxide/multi-walled carbon nanotubes (ZnO/MWCNTs) nanocomposite electrical-insulating coating was investigated. ZnO/MWCNTs was prepared by sol–gel method and incorporated into the epoxy matrix by ultrasonic-mechanical mixing to form the nanocomposite (ZnO/MWCNTs/epoxy). The SEM, XRD, and TGA analysis results showed that ZnO nanoparticles with 3–4 nm size formed layers on MWCNTs wires with a 10-nm diameter. The formed ZnO/CNT nanofillers had a diameter about 20–40 nm and had a highly homogeneous dispersion in the epoxy matrix. The thermal property of the nanocomposites was examined by the thermal imaging method. It was found that both MWCNTs and ZnO/MWCNTs nanofillers have significantly enhanced the thermal conduction of composites even at a low content load of 0.25 wt%. The thermal conductivity of ZnO/MWCNTs/epoxy and MWCNTs/epoxy composites was 0.62 and 1.09 Wm−1 K−1 respectively. The formation of ZnO nanoparticles on MWCNTs was thus led to a decreasing of about 43% in thermal conductivity of the composite. However, the thermal conduction of the ZnO/MWCNTs/epoxy composite is significantly improved about 210% compared to that of neat epoxy. These results proposed a useful method to modify the surface of MWCNTs for the fabrication of epoxy nanocomposite where electrical-insulating and thermal conducting are both required. The composite was applied as an insulating edge coating for capacitive deionization electrodes

    Gallbladder carriage generates genetic variation and genome degradation in Salmonella Typhi

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    Despite recent advances in typhoid fever control, asymptomatic carriage of Salmonella Typhi in the gallbladder remains poorly understood. Aiming to understand if S. Typhi becomes genetically adapted for long-term colonisation in the gallbladder, we performed whole genome sequencing on a collection of S. Typhi isolated from the gallbladders of typhoid carriers. These sequences were compared to contemporaneously sampled sequences from organisms isolated from the blood of acute patients within the same population. We found that S. Typhi carriage was not restricted to any particular genotype or conformation of antimicrobial resistance genes, but was largely reflective of S. Typhi circulating in the general population. However, gallbladder isolates showed a higher genetic variability than acute isolates, with median pairwise SNP distances of 21 and 13 SNPs (p = 2.8x10-9), respectively. Within gallbladder isolates of the predominant H58 genotype, variation was associated with a higher prevalence of nonsense mutations. Notably, gallbladder isolates displayed a higher frequency of non-synonymous mutations in genes encoding hypothetical proteins, membrane lipoproteins, transport/binding proteins, surface antigens, and carbohydrate degradation. Specifically, we identified several gallbladder-specific non-synonymous mutations involved in LPS synthesis and modification, with some isolates lacking the Vi capsular polysaccharide vaccine target due to the 134Kb deletion of SPI-7. S. Typhi is under strong selective pressure in the human gallbladder, which may be reflected phylogenetically by long terminal branches that may distinguish organisms from chronic and acute infections. Our work shows that selective pressures asserted by the hostile environment of the human gallbladder generate new antigenic variants and raises questions regarding the role of carriage in the epidemiology of typhoid fever

    A prospective multi-center observational study of children hospitalized with diarrhea in Ho Chi Minh City, Vietnam.

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    We performed a prospective multicenter study to address the lack of data on the etiology, clinical and demographic features of hospitalized pediatric diarrhea in Ho Chi Minh City (HCMC), Vietnam. Over 2,000 (1,419 symptomatic and 609 non-diarrheal control) children were enrolled in three hospitals over a 1-year period in 2009-2010. Aiming to detect a panel of pathogens, we identified a known diarrheal pathogen in stool samples from 1,067/1,419 (75.2%) children with diarrhea and from 81/609 (13.3%) children without diarrhea. Rotavirus predominated in the symptomatic children (664/1,419; 46.8%), followed by norovirus (293/1,419; 20.6%). The bacterial pathogens Salmonella, Campylobacter, and Shigella were cumulatively isolated from 204/1,419 (14.4%) diarrheal children and exhibited extensive antimicrobial resistance, most notably to fluoroquinolones and third-generation cephalosporins. We suggest renewed efforts in generation and implementation of policies to control the sale and prescription of antimicrobials to curb bacterial resistance and advise consideration of a subsidized rotavirus vaccination policy to limit the morbidity due to diarrheal disease in Vietnam
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