574 research outputs found
Stereomicroscopic evaluation of sealing ability of four different root canal sealers: an in-vitro study
No full textAbstract Aim To compare and evaluate the sealing ability of four different commercially available sealers to provide seal against the dye penetration test using a stereomicroscope-an in-vitro study. Material/Method 80 extracted single rooted mandibular premolar with single canal were used in this study. The samples were divided in 4 groups (20 in each) based on sealer. Group I (Diaproseal), Group II (apexit Plus), Group III (MTA Fillapex) and Group IV (Bio-C). The samples were analyzed using a stereomicroscope and data analysis was done with one-way Anova And post hoc Tukey’s test. Result The mean dye penetration score was 1.2400 ± 0.778 mm for Group I. 2.6000 ± 0.897 mm for Group II, 4.2000 ± 0.923 mm for Group III and 4.225 ± 2.055 mm for Group IV. One-way Anova analysis shows that intergroup comparison was statistically significant between the four groups. The post hoc Tukey’s test reveals that the difference was statistically non-significant between group III and group IV. Conclusion It was concluded that between the four groups the Group I (Diaproseal) showed the least dye penetration followed by Group II (Apexit Pus), Group III (MTA Fillapex) and then Group IV (Bio-C), where there was no significant difference between the Group III (MTA Fillapex) and Group IV (Bio-C)
Sequence- and structure-specific targeting of RNAs by short nucleobase-modified dsRNA-Binding PNAs Incorporating A-U pair-recognizing fluorescent light-up benzothiophene uracil and G-C pair-recognizing guanidinium
No full textThe structures of RNAs determine their functions including protein coding, catalysis, and gene regulation. RNAs are emerging as important therapeutic targets and diagnosis biomarkers. Compared to targeting RNAs through duplex formation, targeting the pre-formed dsRNA regions through structure-specific triplex formation provides a complementary RNA probing/targeting strategy. However, triplex formation through Hoogsteen hydrogen bonding for all base pairs at near-physiological conditions is relatively challenging. We have developed a second-generation modified btU PNA monomer derived from uracil, which recognizes the Watson–Crick A-U base pair and shows fluorescence light-up effect upon binding to dsRNAs. In addition, we developed a novel PNA R monomer for the sequence and structure specific recognition of Watson–Crick G-C base pairs in dsRNAs under physiological pH conditions. Our work provides a modular PNA-based platform for the recognition of biomedically important RNAs for applications in diagnosis and therapeutics.Doctor of Philosoph
Spectre Declassified: Reading from the Right Place at the Wrong Time
No full textPractical information-flow programming languages commonly allow controlled leakage via a declassify construct— programmers can use this construct to declare intentional leakage. For instance, cryptographic signatures and ciphertexts, which are computed from private keys, are viewed as secret by informationflow analyses. Cryptographic libraries can use declassify to make this data public, as it is no longer sensitive. In this paper, we study the interaction between speculative execution and declassification. We show that speculative execution leads to unintended leakage from declassification sites. Concretely, we present a PoC that recovers keys from AES implementations. Our PoC is an instance of a Spectre attack, and remains effective even when programs are compiled with speculative load hardening (SLH), a widespread compiler-based countermeasure against Spectre. We develop formal countermeasures against these attacks, including a significant improvement to SLH we term selective speculative load hardening (selSLH). These countermeasures soundly enforce relative non-interference (RNI): Informally, the speculative leakage of a protected program is limited to the existing sequential leakage of the original program. We implement our simplest countermeasure in the FaCT language and compiler— which is designed specifically for high-assurance cryptography— and we see performance overheads of at most 10%. Finally, although we do not directly implement selSLH, our preliminary evaluation suggests a significant reduction in performance cost for cryptographic functions as compared to traditional SLH.Basavesh Ammanaghatta Shivakumar, Jack Barnes, Gilles Barthe, Sunjay Cauligi, Chitchanok Chuengsatiansup, Daniel Genkin, Sioli O'Connell, Peter Schwabe, Rui Qi Sim, Yuval Yaro
Biocontrol of <I>Rhizoctonia solani</I> Root Rot of Chilli by <I>Bacillus subtilis</I> formulations under Pot Conditions
No full textThe chilli crop suffers massive yield loss due to root rot caused by <em>Rhizoctonia solani</em>. An increase of 10 × 10<sup>5</sup> root colonizing units/cm was obtained as a result of <em>Bacillus subtilis</em> in vitro root colonisation assay post germination. Shelf life studies of the formulations revealed stable population level of the biocontrol agent upto 180<sup>th</sup> day (30°C - 1.6 × 10<sup>8</sup>; 4°C - 1.9 × 10<sup>8</sup>) in talc and upto 150<sup>th</sup> day in lignite (30°C - 1.5 × 10<sup>8</sup>; 4°C - 1.3 × 10<sup>8</sup>). Soil, seed, foliar spray and dip treatment methods of <em>B. subtilis</em> and chlorothalonil brought about a considerable enhancement of all biometric parameters and reduced disease incidence compared to the untreated control. In comparison to the untreated control (50 g and 21 g fresh and dry weight, respectively), highest plant fresh weight (76.84 g) and dry weight (34.17 g) was achieved by the Seed application method. Comparison of plant height revealed maximum values 70 cm (soil application) and 77 cm (dip treatment) with <em>B. subtilis</em> application which was analogous to chlorothalonil treatment (56.5 cm with soil application and 70.33 cm with dip treatment) which was considerably superior to the untreated control (58.2 cm with dip treatment and 61 cm with soil application, respectively). Root dip treatment showed considerable increase in root length with <em>B. subtilis</em> (33 cm) and chlorothalonil (28.5 cm) when compared to untreated control (15 cm). Growth promotion was better with Root dip application while disease control was achieved better with seed application. A 66% and 84% reduction in incitation of disease was noticed with soil and seed application methods, respectively.</jats:p
Pathogenesis of NASH: How Metabolic Complications of Overnutrition Favour Lipotoxicity and Pro-Inflammatory Fatty Liver Disease.
No full textOvernutrition, usually with obesity and genetic predisposition, lead to insulin resistance, which is an invariable accompaniment of nonalcoholic fatty liver disease (NAFLD). The associated metabolic abnormalities, pre- or established diabetes, hypertension and atherogenic dyslipidemia (clustered as metabolic syndrome) tend to be worse for nonalcoholic steatohepatitis (NASH), revealing it as part of a continuum of metabolic pathogenesis. The origins of hepatocellular injury and lobular inflammation which distinguish NASH from simple steatosis have intrigued investigators, but it is now widely accepted that NASH results from liver lipotoxicity. The key issue is not the quantity of liver fat but the type(s) of lipid molecules that accumulate, and how they are “packaged” to avoid subcellular injury. Possible lipotoxic mediators include free (unesterified) cholesterol, saturated free fatty acids, diacylglycerols, lysophosphatidyl-choline, sphingolipids and ceramide. Lipid droplets are intracellular storage organelles for non-structural lipid whose regulation is influenced by genetic polymorphisms, such as PNPLA3. Cells unable to sequester chemically reactive lipid molecules undergo mitochondrial injury, endoplasmic reticulum (ER) stress and autophagy, all processes of interest for NASH pathogenesis. Lipotoxicity kills hepatocytes by apoptosis, a highly regulated, non-inflammatory form of cell death, but also by necrosis, necroptosis and pyroptosis; the latter involve mitochondrial injury, oxidative stress, activation of c-Jun N-terminal kinase (JNK) and release of danger-associated molecular patterns (DAMPs). DAMPs stimulate innate immunity by binding pattern recognition receptors, such as Toll-like receptor 4 (TLR4) and the NOD-like receptor protein 3 (NLRP3) inflammasome, which release a cascade of pro-inflammatory chemokines and cytokines. Thus, lipotoxic hepatocellular injury attracts inflammatory cells, particularly activated macrophages which surround ballooned hepatocytes as crown-like structures. In both experimental and human NASH, livers contain cholesterol crystals which are a second signal for NLRP3 activation; this causes interleukin (IL)-1β and IL18 secretion to attract and activate macrophages and neutrophils. Injured hepatocytes also liberate plasma membrane-derived extracellular vesicles; these have been shown to circulate in NASH and to be pro-inflammatory. The way metabolic dysfunction leads to lipotoxicity, innate immune responses and the resultant pattern of cellular inflammation in the liver are likely also relevant to hepatic fibrogenesis and hepatocarcinogenesis. Pinpointing the key molecules involved pharmacologically should eventually lead to effective pharmacotherapy against NASH
Characterization of nanosilica-Filled epoxy composites for electrical and insulation applications
No full textWe report in this article the results of nanosilica (SiO2)-filled epoxy composites with different loadings and their electrical, thermal, mechanical, and free-volume properties characterized with different techniques. The morphological features were studied by transmission electron microscopy, and differential scanning calorimetry was used to investigate the glass-transition temperature (T-g) of the nanocomposites. The properties of the nanocomposites showed that the electrical resistivity (rho), ultimate tensile strength, and hardness of the composites increased with SiO2 weight fraction up to 10 wt % and decreased there-after; this suggested that the beneficial properties occurred up to this weight fraction. The temperature and seawater aging had a negative influence on rho; that is, rho decreased with increases in the temperature and aging. The free-volume changes (microstructural) in the composite systems correlated with seawater aging but did not correlate so well with the mechanical properties. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 121: 2752-2760, 201
A finite difference method for a class of two-point boundary value problems over a semi-infinite range
No full textAbstractWe examine the three-point finite difference discretization of the two-point boundary value problem: − y″ + f(x)y = g(x), 0 ⩽ x $̌∞, y(0) = y(∞) = 0. Our purpose here is to study the resulting infinite tridiagonal linear system. We first show that, under suitable assumptions, the infinite linear system possesses a unique solution provided inf f(x) = ϵ > 0. We show that the l∞-norm of the discretization error is bounded by Ch2 where h is the step-size and C is a constant independent of h. We assume that ∣ g(x) ∣ ⩽ M e−αχ, for suitable postive constants M and α. We then obtain a bound for the numerical solution yn, at xn, and the bound involves only h, ϵ, M a α. From this bound we conclude that yn → 0 as n → ∞. An interesting application of this bound is that we can obtain an a priori estimate for n so that for this n the numerical solution yn at xn is ‘almost zero’ in the se that ∣ yn ∣ ⩽ δ for a preassigned δ. In other words, this bound provides an a priori estimate for n for truncating the infinite linear system (or equivalently, for truncating the semi-infinite range at xn) so that yn is within the tolerance δ
- …
