275 research outputs found

    Biochar-amended potting medium reduces the susceptibility of rice to root-knot nematode infections

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    Background: Biochar is a solid coproduct of biomass pyrolysis, and soil amended with biochar has been shown to enhance the productivity of various crops and induce systemic plant resistance to fungal pathogens. The aim of this study was to explore the ability of wood biochar to induce resistance to the root-knot nematode (RKN) Meloidogyne graminicola in rice (Oryza sativa cv. Nipponbare) and examine its histochemical and molecular impact on plant defense mechanisms. Results: A 1.2 % concentration of biochar added to the potting medium of rice was found to be the most effective at reducing nematode development in rice roots, whereas direct toxic effects of biochar exudates on nematode viability, infectivity or development were not observed. The increased plant resistance was associated with biochar-primed H2O2 accumulation as well as with the transcriptional enhancement of genes involved in the ethylene (ET) signaling pathway. The increased susceptibility of the Ein2b-RNAi line, which is deficient in ET signaling, further confirmed that biochar-induced priming acts at least partly through ET signaling. Conclusion: These results suggest that biochar amendments protect rice plants challenged by nematodes. This priming effect partially depends on the ET signaling pathway and enhanced H2O2 accumulation

    Bandwidth-sensitive oblivious routing

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    Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Includes bibliographical references (p. 81-83).Traditional oblivious routing algorithms either do not take into account the bandwidth demand, or assume that each flow has its own private channel to guarantee deadlock freedom. Though adaptive routing schemes can react to varying network traffic, they require complicated router designs. In this thesis, we present a polynomial-time heuristic routing algorithm that takes bandwidth requirements of each flow into account to minimize maximum channel load. The heuristic algorithm has two variants. The first one produces a deadlock-free route. The second one produces a minimal route, and is deadlock-free with two or more virtual channels assuming proper VC allocation. Both routing algorithms are oblivious, and need only simple router designs. The performance of each bandwidth-sensitive routing algorithm is evaluated against dimension-order routing and against the other on a number of benchmarks.by Tina Wen.M.Eng

    PFAS in Aerosols Released During Bathroom Showering

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    Poly- and Perfluoroalkyl substances (PFAS) are characterized by strong bonds between carbon and fluorine atoms giving them long environmental lifetimes and the ability to bioaccumulate in humans, animals and plants. PFAS compounds have been detected in ground water, surface water bodies and municipal waters. They are widely used in personal care products as surfactants which provides pathways for human exposure. To my knowledge, human exposure to PFAS during showering has not been studied. The goal of this project is to measure the amount of PFAS that humans are exposed to while showering with or without the use of personal care products. PFAS concentrations were measured in scenarios background, water only, and a full shower with personal care product use. Results suggest that shower activities might contribute to bathroom PFNA, PFOA, PFHxA exposures; however the dataset is limited in size, findings are not statistically significant, and thus more measurements are warranted.Master of Science in Environmental Engineerin

    Design and implementation of mobile learning at Open University Malaysia (OUM)

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    With learners going mobile, supporting their learning through mobile phones appears to be timely and appropriate, especially for learners in an open and distance learning environment. Mobile learning in the form of short messaging service was piloted with one of the University’s first semester compulsory courses in May 2009. The course, “Learning Skills for Open and Distance Learners” was selected on the basis of its importance in preparing learners for the learning environment at the University. At the end of the course the students are expected to be able to have been able to manage their learning better and to benefit from the blend of pedagogies. The text messages were designed in such a way as to prompt learners to apply principles related to, among others, the study skills, time management, stress management and use the university’s learning management system, digital library collection and participate in the online forums. The approach taken was to ensure that learners were prompted to think, read, practice or discuss issues during the class tutorials or forums. The five types of text messages were those related to forum, content, tips, motivation and course management. The paper describes the design and implementation of the mobile learning initiative at OUM. Feedback from 712 students using a questionnaire is also included in the paper. (Authors' abstract

    Static virtual channel allocation in oblivious routing

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    Most virtual channel routers have multiple virtual channels to mitigate the effects of head-of-line blocking. When there are more flows than virtual channels at a link, packets or flows must compete for channels, either in a dynamic way at each link or by static assignment computed before transmission starts. In this paper, we present methods that statically allocate channels to flows at each link when oblivious routing is used, and ensure deadlock freedom for arbitrary minimal routes when two or more virtual channels are available. We then experimentally explore the performance trade-offs of static and dynamic virtual channel allocation for various oblivious routing methods, including DOR, ROMM, Valiant and a novel bandwidth-sensitive oblivious routing scheme (BSORM). Through judicious separation of flows, static allocation schemes often exceed the performance of dynamic allocation schemes

    Application-Aware Deadlock-Free Oblivious Routing

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    Conventional oblivious routing algorithms are either not application-aware or assume that each flow has its own private channel to ensure deadlock avoidance. We present a framework for application-aware routing that assures deadlock-freedom under one or more channels by forcing routes to conform to an acyclic channel dependence graph. Arbitrary minimal routes can be made deadlock-free through appropriate static channel allocation when two or more channels are available. Given bandwidth estimates for flows, we present a mixed integer-linear programming (MILP) approach and a heuristic approach for producing deadlock-free routes that minimize maximum channel load. The heuristic algorithm is calibrated using the MILP algorithm and evaluated on a number of benchmarks through detailed network simulation. Our framework can be used to produce application-aware routes that target the minimization of latency, number of flows through a link, bandwidth, or any combination thereof

    DRMref: Comprehensive Reference Map of Drug Resistance Mechanisms in Human Cancer

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    Drug resistance poses a significant challenge in cancer treatment. Despite the initial effectiveness of therapies such as chemotherapy, targeted therapy and immunotherapy, many patients eventually develop resistance. To gain deep insights into the underlying mechanisms, single-cell profiling has been performed to interrogate drug resistance at cell level. Herein, we have built the DRMref database (https://ccsm.uth.edu/DRMref/) to provide comprehensive characterization of drug resistance using single-cell data from drug treatment settings. The current version of DRMref includes 42 single-cell datasets from 30 studies, covering 382 samples, 13 major cancer types, 26 cancer subtypes, 35 treatment regimens and 42 drugs. All datasets in DRMref are browsable and searchable, with detailed annotations provided. Meanwhile, DRMref includes analyses of cellular composition, intratumoral heterogeneity, epithelial-mesenchymal transition, cell-cell interaction and differentially expressed genes in resistant cells. Notably, DRMref investigates the drug resistance mechanisms (e.g. Aberration of Drug\u27s Therapeutic Target, Drug Inactivation by Structure Modification, etc.) in resistant cells. Additional enrichment analysis of hallmark/KEGG (Kyoto Encyclopedia of Genes and Genomes)/GO (Gene Ontology) pathways, as well as the identification of microRNA, motif and transcription factors involved in resistant cells, is provided in DRMref for user\u27s exploration. Overall, DRMref serves as a unique single-cell-based resource for studying drug resistance, drug combination therapy and discovering novel drug targets

    Investigation of Type 2 Diabetes Risk Alleles Support CDKN2A/B, CDKAL1, and TCF7L2 As Susceptibility Genes in a Han Chinese Cohort

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    Background: Recent genome-wide association studies (GWASs) have reported several genetic variants to be reproducibly associated with type 2 diabetes. Additional variants have also been detected from a metaanalysis of three GWASs, performed in populations of European ancestry. In the present study, we evaluated the influence of 17 genetic variants from 15 candidate loci, identified in type 2 diabetes GWASs and the metaanalysis, in a Han Chinese cohort. Methodology/Principal Findings: Selected type 2 diabetes-associated genetic variants were genotyped in 1,165 type 2 diabetic patients and 1,136 normoglycemic control individuals of Southern Han Chinese ancestry. The OR for risk of developing type 2 diabetes was calculated using a logistic regression model adjusted for age, sex, and BMI. Genotype-phenotype associations were tested using a multivariate linear regression model. Genetic variants in CDKN2A/B, CDKAL1, TCF7L2, TCF2, MC4R, and PPARG showed a nominal association with type 2 diabetes (P <= 0.05), of whom the three first would stand correction for multiple testing: CDKN2A/B rs10811661, OR: 1.26 (1.12-1.43) P = 1.8* 10(-4); CDKAL1 rs10946398, OR: 1.23 (1.09-1.39); P = 7.1* 10(-4), and TCF7L2 rs7903146, OR: 1.61 (1.19-2.18) P = 2.3* 10(-3). Only nominal phenotype associations were observed, notably for rs8050136 in FTO and fasting plasma glucose (P = 0.002), postprandial plasma glucose (P = 0.002), and fasting C-peptide levels (P = 0.006) in the diabetic patients, and with BMI in controls (P = 0.033). Conclusions/Significance: We have identified significant association between variants in CDKN2A/B, CDKAL1 and TCF7L2, and type 2 diabetes in a Han Chinese cohort, indicating these genes as strong candidates conferring susceptibility to type 2 diabetes across different ethnicities

    Scoring mechanisms of p16INK4a immunohistochemistry based on either independent nucleic stain or mixed cytoplasmic with nucleic expression can significantly signal to distinguish between endocervical and endometrial adenocarcinomas in a tissue microarray study

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    <p>Abstract</p> <p>Background</p> <p>Endocervical adenocarcinomas (ECAs) and endometrial adenocarcinomas (EMAs) are malignancies that affect uterus; however, their biological behaviors are quite different. This distinction has clinical significance, because the appropriate therapy may depend on the site of tumor origin. The purpose of this study is to evaluate 3 different scoring mechanisms of p16<sup>INK4a </sup>immunohistochemical (IHC) staining in distinguishing between primary ECAs and EMAs.</p> <p>Methods</p> <p>A tissue microarray (TMA) was constructed using formalin-fixed, paraffin-embedded tissue from hysterectomy specimens, including 14 ECAs and 24 EMAs. Tissue array sections were immunostained with a commercially available antibody of p16<sup>INK4a</sup>. Avidin-biotin complex (ABC) method was used for antigens visualization. The staining intensity and area extent of the IHC reactions was evaluated using the semi-quantitative scoring system. The 3 scoring methods were defined on the bases of the following: (1) independent cytoplasmic staining alone (Method C), (2) independent nucleic staining alone (Method N), and (3) mean of the sum of cytoplasmic score plus nucleic score (Method Mean of C plus N).</p> <p>Results</p> <p>Of the 3 scoring mechanisms for p16<sup>INK4a </sup>expression, Method N and Method Mean of C plus N showed significant (<it>p-values </it>< 0.05), but Method C showed non-significant (p = 0.245) frequency differences between ECAs and EMAs. In addition, Method Mean of C plus N had the highest overall accuracy rate (81.6%) for diagnostic distinction among these 3 scoring methods.</p> <p>Conclusion</p> <p>According to the data characteristics and test effectiveness in this study, Method N and Method Mean of C plus N can significantly signal to distinguish between ECAs and EMAs; while Method C cannot do. Method Mean of C plus N is the most promising and favorable means among the three scoring mechanisms.</p
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