Evidence of robust 2D transport and Efros-Shklovskii variable range hopping in disordered topological insulator (Bi2Se3) nanowires

We report the experimental observation of variable range hopping conduction in focused-ion-beam (FIB) fabricated ultra-narrow nanowires of topological insulator (Bi2Se3). The value of the exponent in the hopping equation was extracted as ~ 1/2 for different widths of nanowires, which is the proof of the presence of Efros-Shklovskii hopping transport mechanism in a strongly disordered system. High localization lengths (0.5nm, 20nm) were calculated for the devices. A careful analysis of the temperature dependent fluctuations present in the magnetoresistance curves, using the standard Universal Conductance Fluctuation theory, indicates the presence of 2D topological surface states. Also, the surface state contribution to the conductance was found very close to one conductance quantum. We believe that our experimental findings shed light on the understanding of quantum transport in disordered topological insulator based nanostructures.Comment: 14pages, 4 figure

Anisotropic weakly localized transport in nitrogen-doped ultrananocrystalline diamond films

We establish the dominant effect of anisotropic weak localization (WL) in three dimensions associated with a propagative Fermi surface, on the conductivity correction in heavily nitrogen doped ultrananocrystalline diamond (UNCD) films based on magneto-resistance studies at low temperatures. Also, low temperature electrical conductivity can show weakly localized transport in 3D combined with the effect of electron-electron interactions in these materials, which is remarkably different from the conductivity in 2DWL or strong localization regime. The corresponding dephasing time of electronic wavefunctions in these systems described as ~ T^-p with p < 1, follows a relatively weak temperature dependence compared to the generally expected nature for bulk dirty metals having $p \geq 1$. The temperature dependence of Hall (electron) mobility together with an enhanced electron density has been used to interpret the unusual magneto-transport features and show delocalized electronic transport in these n-type UNCD films, which can be described as low-dimensional superlattice structures.Comment: 27 pages, 6 figures, To be published in Physical Review

DEVELOPMENT AND VALIDATION OF RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF IVERMECTIN AND CLORSULON IN IVERCAM INJECTION

A precise, simple, accurate and selective method was developed and validate for estimation of Ivermectin and Clorsulon in Ivercam injection, Reversed phase high performance liquid chromatographic (RP-HPLC) method was developed for routine quantification of Ivermectin and Clorsulon in laboratory prepared mixtures as well as in combined dosage form. Chromatographic separation was achieved on a BDS hypersil C18 (5μ, 250 x 4.6 mm) utilizing mobile phase of filtered and degassed mixture of 60 phosphate buffer (pH 5.5 adjusted with 1% O-phosphoric acid) and Methanol (60:40 v/v) at a flow rate of 1 mL/min with UV detection at 234 nm. The method has been validated for linearity, accuracy and precision. In RP-HPLC method, the calibration graphs were linear in the concentration range of 2.5-7.5 μg/ml for Ivermectin and 25-75 μg/ml for Clorsulon with percentage recoveries of 100.34 % and 99.76% for Ivermectin and Clorsulon respectively. Conclusion: The results obtained by RP-HPLC methods are rapid, accurate and precise. Therefore proposed method can be used for routine analysis of Clorsulon and Ivermectin in injection

Comparative evaluation of antimicrobial activity of herbal extracts with 5.25% sodium hypochlorite against multispecies dentinal biofilm

Aims: To check the antimicrobial activity of Tinospora cordifolia (TC) (Giloy), Ocimum sanctum (Tulsi), and 5.25% sodium hypochlorite (NaOCl) against 21-day-old multispecies biofilm formed on tooth substrate of extracted human teeth. Settings and Design: In vitro dentin disinfection model used to check the antimicrobial efficacy of herbal extracts. Materials and Methods: The in vitro dentin disinfection model was used to check the antimicrobial activity of the methanolic extracts of medicinal plants along with NaOCl. The polymicrobial biofilm was allowed to grow on extracted teeth sections for a period of 21 days. Remaining microbial load in the form of CFU/ml after the antimicrobial treatment was tabulated and data were statistically analyzed using ANOVA and Bonferroni post-hoc tests. Statistical Analysis Used: SPSS version 17 one-way ANOVA, Bonferroni post-hoc test. Results: Both the plant extracts showed considerable antimicrobial efficacy as compared to negative control. About 5.25% NaOCl was the most effective antimicrobial agent having statistically significant difference against plant extracts and negative control (saline). Conclusions: The methanolic extract of TC (Giloy), O. sanctum (Tulsi), and 5.25% NaOCl has considerable antimicrobial activity against polymicrobial dentinal biofilm of Streptococcus mutans, Enterococcus faecalis, Staphylococcus aureus, and Candida albicans

Detecting Illicit Entities in Bitcoin using Supervised Learning of Ensemble Decision Trees

International audienceSince its inception in 2009, Bitcoin has been mired in controversies for providing a haven for illegal activities. Several types of illicit users hide behind the blanket of anonymity. Uncovering these entities is key for forensic investigations. Current methods utilize machine learning for identifying these illicit entities. However, the existing approaches only focus on a limited category of illicit users. The current paper proposes to address the issue by implementing an ensemble of decision trees for supervised learning. More parameters allow the ensemble model to learn discriminating features that can categorize multiple groups of illicit users from licit users. To evaluate the model, a dataset of 2059 real-life entities on Bitcoin was extracted from the Blockchain. Nine features were engineered to train the model for segregating 28 different licit-illicit categories of users. The proposed model provided a reliable tool for forensic study. Empirical evaluation of the proposed model vis-a-vis three existing benchmark models was performed to highlight its efficacy. Experiments showed that the specificity and sensitivity of the proposed model were comparable to other models

Evaluation of Pulse Rate, Oxygen Saturation, and Respiratory Effort after Different Types of Feeding Methods in Preterm Newborns

Background. During the initial days of hospitalization, preterm newborns are given combinations of breastfeeding, spoon/paladai feeding, and/or gavage feeding. Each method of feeding may have a different effect on vital parameters. Objective. To study changes in vital parameters in relation to different feeding methods and postmenstrual age (PMA) in preterm newborns. Study Design. This prospective observational study was carried out at a tertiary care neonatal unit. Participants. Physiologically stable preterm newborns with PMA less than 37 weeks on full enteral feeds were included in the study. Intervention. None. Outcomes. Respiratory rate (RR), pulse rate (PR), oxygen saturation (SPO2), nasal flaring, and lower chest indrawing were monitored before and up to 3 h after the breastfeeding/spoon (paladai) feeding/gavage feeding or their combinations. These vital parameters were assessed in relation to the feeding methods and PMA groups using ANOVA. Results. A total of 383 records were analyzed from 110 newborns. No infant developed chest indrawing or nasal flaring after any feeding method. During the 3 h period of monitoring, vital parameters changed significantly except in the gavage feeding group. The mean PR did not change, but the mean RR and SPO2 changed significantly at different PMA. Conclusion. Vital parameters changed after different types of feeding methods and at different PMA. A further multicentric prospective study is needed to understand the effect of different feeding methods and PMA on vital parameters

Degradation behavior of MgB<SUB>2</SUB> superconductor

The degradation behavior of polycrystalline MgB2 superconductor, exposed to water and ambient atmosphere, has been studied. We have found that prolonged exposure to water completely destroys superconductivity. Optical microscopic and X-ray diffraction analyses indicate that, on exposure to water, the material becomes amorphous like. X-ray photoelectron spectroscopic measurements reveal the strongly hygroscopic character of MgB2 and we have found that, even at room temperature, water and air change it into Mg(OH)2, MgCO3 and B2O3

INTRAVITREAL OCRIPLASMIN IN CLINICAL PRACTICE: Predictors of Success, Visual Outcomes, and Complications

To investigate predictors of success, visual outcomes, and complications of intravitreal ocriplasmin for the treatment of symptomatic vitreomacular adhesion in a clinical care setting. Retrospective chart review of 49 consecutive eyes of 47 patients who received intravitreal ocriplasmin. Spectral domain optical coherence tomography scans were examined for vitreomacular traction (VMT) release, full-thickness macular hole (FTMH) closure, and other changes in retinal anatomy. Pharmacologic VMT release occurred in 41% of eyes; positive predictors included age ≤75 years (P = 0.001), phakic status (P = 0.016), VMT width ≤750 μm (P = 0.001), and absence of retinal comorbidities (P = 0.035). Pharmacologic FTMH closure occurred in 25% of cases; positive predictors included successful VMT release (P = 0.042), better preinjection best-corrected visual acuity (P = 0.036), and smaller FTMH aperture width (P = 0.033). Eyes that achieved VMT release and did not undergo surgery attained significant improvement in best-corrected visual acuity (P = 0.015). Complications included subfoveal lucency (33%), ellipsoid zone disruption (33%), and FTMH base enlargement (75%). Only FTMH base enlargement resulted in worse visual outcomes (P = 0.024). Subgroup analysis of 14 eyes with ideal characteristics (all positive predictors listed above) yielded a 93% VMT release rate. Proper case selection may facilitate successful pharmacologic vitreolysis with ocriplasmin, improve visual outcomes, and minimize potential complications