Measurement of J/ψ azimuthal anisotropy in Au+Au collisions at sqrt[s(NN)]=200 GeV

The measurement of J/ψ azimuthal anisotropy is presented as a function of transverse momentum for different centralities in Au+Au collisions at sqrt[s(NN)]=200 GeV. The measured J/ψ elliptic flow is consistent with zero within errors for transverse momentum between 2 and 10 GeV/c. Our measurement suggests that J/ψ particles with relatively large transverse momenta are not dominantly produced by coalescence from thermalized charm quarks, when comparing to model calculations.

Role of casein phosphopeptide amorphous calcium phosphate in remineralization of white spot lesions and inhibition of Streptococcus mutans?

INTRODUCTION

To promote the remineralization by ionic exchange mechanism instead of invasive techniques many remineralizing agents can be used.

OBJECTIVE

To evaluate the remineralization effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on white spot lesions (WSLs) and its inhibitory effect on Streptococcus mutans colonization.

MATERIALS AND METHODS

The study group consisted of 60 subjects exhibiting at least 1-WSL. Subjects were randomly divided into 2 groups: A test group using CPP-ACP cream (GC-Tooth Mousse, Leuven, Belgium) and a control group using only fluoride containing toothpaste for a period of 3-month. Baseline WSLs were scored using DIAGNOdent device (KaVo Germany) and the saliva samples were collected to measure S. mutans counts. After the 3-month period the WSLs were again recorded and the saliva collection was repeated.

RESULT

DIAGNOdent measurements were increased by time (P = 0.002) in the control group and no statistically significant difference (P = 0.217) was found in the test group by the 3-month period. In both groups, the mutans counts were decreased in the 3-month experimental period.

CONCLUSION

These clinical and laboratory results suggested that CPP-ACP containing cream had a slight remineralization effect on the WSL in the 3-month evaluation period however, longer observation is recommended to confirm whether the greater change in WSLs is maintained.

Retapamulin: a newer topical antibiotic

Impetigo is a common childhood skin infection. There are reports of increasing drug resistance to the currently used topical antibiotics including fusidic acid and mupirocin. Retapamulin is a newer topical agent of pleuromutilin class approved by the Food and Drug Administration for treatment of impetigo in children and has been recently made available in the Indian market. It has been demonstrated to have low potential for the development of antibacterial resistance and a high degree of potency against poly drug resistant Gram-positive bacteria found in skin infections including Staphylococcus aureus strains. The drug is safe owing to low systemic absorption and has only minimal side-effect of local irritation at the site of application.

Evaluation of viral heterogeneity using next-generation sequencing, end-point limiting-dilution and mass spectrometry

Hepatitis C Virus sequence studies mainly focus on the viral amplicon containing the Hypervariable region 1 (HVR1) to obtain a sample of sequences from which several population genetics parameters can be calculated. Recent advances in sequencing methods allow for analyzing an unprecedented number of viral variants from infected patients and present a novel opportunity for understanding viral evolution, drug resistance and immune escape. In the present paper, we compared three recent technologies for amplicon analysis: (i) Next-Generation Sequencing; (ii) Clonal sequencing using End-point Limiting-dilution for isolation of individual sequence variants followed by Real-Time PCR and sequencing; and (iii) Mass spectrometry of base-specific cleavage reactions of a target sequence. These three technologies were used to assess intra-host diversity and inter-host genetic relatedness in HVR1 amplicons obtained from 38 patients (subgenotypes 1a and 1b). Assessments of intra-host diversity varied greatly between sequence-based and mass-spectrometry-based data. However, assessments of inter-host variability by all three technologies were equally accurate in identification of genetic relatedness among viral strains. These results support the application of all three technologies for molecular epidemiology and population genetics studies. Mass spectrometry is especially promising given its high throughput, low cost and comparable results with sequence-based methods.

Coordinated evolution of the hepatitis B virus polymerase

The detection of compensatory mutations that abrogate negative fitness effects of drug-resistance and vaccine-escape mutations indicates the important role of epistatic connectivity in evolution of viruses, especially under the strong selection pressures. Mapping of epistatic connectivity in the form of coordinated substitutions should help to characterize molecular mechanisms shaping viral evolution and provides a tool for the development of novel anti-viral drugs and vaccines. We analyzed coordinated variation among amino acid sites in 370 the hepatitis B virus (HBV) polymerase sequences using Bayesian networks. Among the HBV polymerase domains the spacer domain separating terminal protein from the reverse-transcriptase domain, showed the highest network centrality. Coordinated substitutions preserve the hydrophobicity and charge of Spacer. Maximum likelihood estimates of codon selection showed that Spacer contains the highest number of positively selected sites. Identification of 67% of the domain lacking an ordered structure suggests that Spacer belongs to the class of intrinsically disordered domains and proteins whose crucial functional role in the regulation of transcription, translation and cellular signal transduction has only recently been recognized. Spacer plays a central role in the epistatic network associating substitutions across the HBV genome, including those conferring viral virulence, drug resistance and vaccine escape. The data suggest that Spacer is extensively involved in coordination of HBV evolution.

Influences of external vs. core-shell mixing on aerosol optical properties at various relative humidities

Aerosol optical properties of external and core-shell mixtures of aerosol species present in the atmosphere are calculated in this study for different relative humidities. Core-shell Mie calculations are performed using the values of radii, refractive indices and densities of aerosol species that act as core and shell, and the core-shell radius ratio. The single scattering albedo (SSA) is higher when the absorbing species (black carbon, BC) is the core, while for a sulfate core SSA does not vary significantly as the BC in the shell dominates the absorption. Absorption gets enhanced in core-shell mixing of absorbing and scattering aerosols when compared to their external mixture. Thus, SSA is significantly lower for a core-shell mixture than their external mixture. SSA is more sensitive to core-shell ratio than mode radius when BC is the core. The extinction coefficient, SSA and asymmetry parameter are higher for external mixing when compared to BC (core)-water soluble aerosol (shell), and water soluble aerosol (core)-BC (shell) mixtures in the relative humidity range of 0 to 90%. Spectral SSA exhibits the behaviour of the species which acts as a shell in core-shell mixing. The asymmetry parameter for an external mixture of water soluble aerosol and BC is higher than BC (core)-water soluble aerosol (shell) mixing and increases as function of relative humidity. The asymmetry parameter for the water soluble aerosol (core)-BC (shell) is independent of relative humidity as BC is hydrophobic. The asymmetry parameter of the core-shell mixture decreases when BC aerosols are involved in mixing, as the asymmetry parameter of BC is lower. Aerosol optical depth (AOD) of core-shell mixtures increases at a higher rate when the relative humidity exceeds 70% in continental clean and urban aerosol models, whereas AOD remains the same when the relative humidity exceeds 50% in maritime aerosol models. The SSA for continental aerosols varies for core-shell mixing of water soluble aerosol (core)-shell (BC) when compared to their external mixture, while the SSA for maritime aerosols does not vary significantly for different mixing scenarios because of the dominance of sea salt aerosols. Thus, these results confirm that aerosol mixing can modify the physical and optical characteristics of aerosols, which vary as a function of relative humidity. These calculations will be useful in parameterising the effect of core-shell vs. external mixing of aerosols in global climate models, and in the evaluation of aerosol radiative effects.

Observation of an energy-dependent difference in elliptic flow between particles and antiparticles in relativistic heavy ion collisions

Elliptic flow (v(2)) values for identified particles at midrapidity in Au + Au collisions, measured by the STAR experiment in the beam energy scan at RHIC at sqrt[s(NN)] = 7.7-62.4 GeV, are presented. A beam-energy-dependent difference of the values of v(2) between particles and corresponding antiparticles was observed. The difference increases with decreasing beam energy and is larger for baryons compared to mesons. This implies that, at lower energies, particles and antiparticles are not consistent with the universal number-of-constituent-quark scaling of v(2) that was observed at sqrt[s(NN)] = 200 GeV.

Airborne black carbon concentrations over an urban region in western India-temporal variability, effects of meteorology, and source regions

This study characterizes over 5 years of high time resolution (5 min), airborne black carbon (BC) concentrations (July 2003 to December 2008) measured over Ahmedabad, an urban region in western India. The data were used to obtain different time averages of BC concentrations, and these averages were then used to assess the diurnal, seasonal, and annual variability of BC over the study region. Assessment of diurnal variations revealed a strong association between BC concentrations and vehicular traffic. Peaks in BC concentration were co-incident with the morning (0730 to 0830, LST) and late evening (1930 to 2030, LST) rush hour traffic. Additionally, diurnal variability in BC concentrations during major festivals (Diwali and Dushera during the months of October/November) revealed an increase in BC concentrations due to fireworks displays. Maximum half hourly BC concentrations during the festival days were as high as 79.8 μg m(-3). However, the high concentrations rapidly decayed suggesting that local meteorology during the festive season was favorable for aerosol dispersion. A multiple linear regression (MLR) model with BC as the dependent variable and meteorological parameters as independent variables was fitted. The variability in temperature, humidity, wind speed, and wind direction accounted for about 49% of the variability in measured BC concentrations. Conditional probability function (CPF) analysis was used to identify the geographical location of local source regions contributing to the effective BC measured (at 880 nm) at the receptor site. The east north-east (ENE) direction to the receptor was identified as a major source region. National highway (NH8) and two coal-fired thermal power stations (at Gandhinagar and Sabarmati) were located in the identified direction, suggesting that local traffic and power plant emissions were likely contributors to the measured BC.

Convergence of HbA1c values towards target in 272 primary care patients following nine years of target-driven care

BACKGROUND

We wished to determine the effect of a target-driven incentivised programme on haemoglobin A1c (HbA1c ) values in a UK diabetic population.

METHODS

An audit was carried out in 1999-2000, which included an estimation of glycaemic control in a randomly selected diabetic cohort from ten primary care practices in Sutton Coldfield, serving a population of 90 000 patients. Each practice was given a randomised list of patients and asked to complete detailed questionnaires on patients with confirmed diabetes. We collected data on 516 patients, 425 of whom had their HbA1c measured in 1999-2000 (Audit 2000). A re-audit of HbA1c was carried out in 2007-08 (Audit 2008) determining the changes in HbA1c since the original audit. Of the original cohort, 272 patients had an audit of HbA1c carried out in Audit 2008.

RESULTS

Overall, a small increase in median and mean HbA1c values was observed. We estimated that the proportion of patients with HbA1c achieving the lower Quality and Outcomes Framework HbA1c target of < 7.5%; 173 of the 272 patients met this target in Audit 2000, whereas the number was 162 in Audit 2008. To understand the changes observed, patients were stratified as quintiles based on the HbA1c in Audit 2000 and changes in HbA1c after 8 years for each quintile were estimated. The mean changes for the different quintiles are: quintile 1 (HbA1c < 6.1%), +1.49%; quintile 2 (HbA1c 6.1- 6.6%), +0.8%; quintile 3 (HbA1c 6.7-7.3%), +0.3%; quintile 4 (HbA1c 7.4-8.5%), -0.18%; and quintile 5 (HbA1c > 8.5%), -1.55%.

CONCLUSION

Our results suggest that, eight years on, patients with poor glycaemic control in 2000 saw an overall decrease in HbA1c by 2008, with the reverse seen in patients with good control.

A comparative evaluation on the cleaning and shaping ability of three nickel titanium rotary instruments using computerized tomography - An ex vivo study

Introduction:

Successful root canal treatment depends primarily on the removal of micro-organisms through chemo-mechanical instrumentation of the root canal system. This encompasses shaping by mechanical removal of the dentine and cleaning by chemical disinfection of microorganisms and dissolution of organic tissues from the root canal. While root canal shaping can be predictably and efficiently attained with advanced instrumentation technology, effective cleaning of the entire root canal system remains a challenge. Rotary nickel titanium instruments are known for their efficient preparation of root canal. This is mainly because of the super elasticity of the nickel titanium alloy which gives an increased flexibility and allows the instrument to efficiently follow the original path of root canal. The purpose of this study is to compare the cleaning efficiency and shaping ability of M two, K3, Race ni-ti rotary instruments during the preparation of curved canals in extracted molars.

Materials and Methods:

Thirty teeth with 18 mm as their working length were selected and divided into three groups of 10 teeth each Angle of curvature, Radius of curvature, was determined using computerized tomography. A Pre and Post-operative measurement of canal width and volume was recorded and compared using CT. The teeth was then sectioned into two halves and subjected to scanning electron microscope. Images were taken at the level of apical third, middle third and coronal third for debris and smear layer. Scoring was done separately for both debris and smear layer.

Results:

Results were tabulated and statistically analyzed to evaluate the shaping ability and cleaning efficiency. Instruments were examined for any deformation or fracture during canal preparation.

Conclusion:

M two showed greater enlargements in all the three levels, when compared its width and volume, with other two instruments. K3 was better than Race when compared among them. In the scanning electron microscope study for debris and smear layer M Two performed better followed by K3 and Race.

Comparison of the push-out shear bond strength of four types of glass ionomers when used to bond amalgam: An in vitro study

Background:

Dental amalgam is the primary direct posterior restorative material used worldwide, but it have certain shortcomings due to the lack of adhesiveness to the cavity. The introduction of the concept of bonded amalgam helped improve the use of amalgam as a restorative material.

Aim:

Evaluation of the comparative push-out shear bond strength of four types of conventional glass ionomers used to bond amalgam to tooth in simulated class I situations.

Materials and Methods:

Four chemical cure glass ionomers are used: GC Fuji I, GC Fuji II, GC Fuji III and GC Fuji VII, and are compared with unbonded amalgam. The push-out bond strength was tested using the Instron Universal Testing Machine at a crosshead speed of 0.5 mm/min.

Statistical Analysis:

One-way ANOVA and post hoc Bonferroni tests were used to analyze the data.

Results:

The results showed that the use of glass ionomer to bond amalgam resulted in an increase in the bond strength of amalgam. The Type VII glass ionomer showed the highest bond strength in comparison with the other glass ionomers.

Conclusions:

Conventional glass ionomer bonds to amalgam and shows a beneficial increase in the bond strength of the restoration in comparison with unbonded amalgam.

T regulatory cells play a significant role in modulating MHC class I antibody-induced obliterative airway disease

The molecular mechanisms leading to the development of chronic lung allograft dysfunction following de novo development of antibodies to mismatched donor MHC remain undefined. We demonstrated that intrabronchial administration of antibodies to MHC class I resulted in induction of both innate and adaptive cellular immune responses characterized by a predominance of Th17 specific to lung associated self-antigens Kα1-tubulin and Collagen-V leading to the development of obliterative airway lesions (OAD), correlate of chronic rejection following human lung transplantation. To determine the role of regulatory T cells (Treg) in the pathogenesis of OAD, we administered anti-MHC class I to mice, in which Treg were depleted by conditional ablation of FoxP3+cells. Under this condition, we observed a threefold increase in pulmonary cellular infiltration, luminal occlusion and fibrous deposition when compared anti-MHC class I Ab administered mice maintaining FoxP3. OAD lesions were accompanied with enhanced accumulation of neutrophils along with self-antigen-specific Th17 and humoral responses. However, IL-17-blockade or adoptive transfer of Treg abrogated OAD. We conclude that Treg exerts a suppressive effect on anti-MHC induced IL-8-mediated neutrophil infiltration and innate immune responses that leads to inhibition of Th17 immune responses to lung associated self-antigens which is critical for development of OAD.

Sensing with optical vortices in photonic-crystal fibers

We demonstrate optical polarization vortex generation in a photonic-crystal fiber (PCF) by means of a CO(2) laser-induced long period grating. Vortices are a special subclass of fiber modes that result in polarization-insensitive resonances even when grating perturbations are asymmetric, as is the case with structural perturbations in single-material PCFs. The physics of vortex generation, combined with the use of structural perturbations alone, in single-material fibers, opens up a new schematic for realizing harsh-environment sensors. We show that the temperature and polarization stability of our vortex devices is maintained for prolonged periods of time (tested up to 34 h) at temperatures exceeding 1000 °C. We envisage that this demonstration opens up a new way of realizing high-temperature sensors in a cost-effective manner.

Resonant bend loss in leakage channel fibers

Leakage channel fibers, designed to suppress higher-order modes, demonstrate resonant power loss at certain critical radii of curvature. Outside the resonance, the power recovers to the levels offset by the usual mechanism of bend-induced loss. Using C2 imaging, we experimentally characterize this anomaly and identify the corresponding physical mechanism as the radiative decay of the fundamental mode mediated by the resonant coupling to a cladding mode.

Polarization-resolved imaging of an ensemble of waveguide modes

We demonstrate polarization-sensitive measurement of the modal content of waveguides by generalizing the classic rotating wave-plate-based polarimeter to wide-field optical low-coherence interferometry. The spatial phases of the modes are retrieved with principal component analysis. By applying this polarization-sensitive cross-correlation (C2) imaging technique to the characterization of a few-mode fiber, we reveal that different modes experience distinct bend-induced birefringence in optical fibers. This polarization-resolved C2 imaging is well suited for analyzing the impact of polarization on wave propagation in high-power fiber lasers as well as in mode-division-multiplexed communications systems.

The substitutions G245C and G245D in the Zn(2+)-binding pocket of the p53 protein result in differences of conformational flexibility of the DNA-binding domain

Transcription activation of the proapoptotic target genes is a means by which the p53 protein implements its function of tumor suppression. Zn(2+) is a known regulator of p53 binding to the target genes. We have previously obtained an evidence that amino acid substitutions in the p53 Zn(2+)-binding pocket can presumably exert an influence on Zn(2+) position in the Zn(2+)-p53 complex and thereby affect p53 binding to DNA. With these background considerations, our aim was to estimate the effect of the putative changes in the Zn(2+) position in its binding pocket due to the G245C and G245D substitutions on the conformation of the p53 DNA-binding motif. Statistical analysis of the molecular dynamics (MD) trajectories of the mutant p53-Zn(2+) complexes was used to detect significant deviations in conformation of the mutant p53 forms. MD simulations demonstrated that (1) the two substitutions in the Zn(2+)-binding pocket caused changes in the conformation of the p53 DNA-binding motif, as compared with the wild-type (WT) p53; (2) binding of Zn(2+) to the p53 mutant forms reduced the effect of the substitutions on conformational change; and (3) Zn(2+) binding in the normal position compensated the effect of the mutations on the conformation in comparison to the altered Zn(2+) position.

Radiative effects of aerosols over Indo-Gangetic plain: environmental (urban vs. rural) and seasonal variations

Aerosol radiative effects over two environmentally distinct locations, Kanpur (urban site) and Gandhi College (rural location) in the Indo-Gangetic plain (IGP), a regional aerosol hot spot, utilizing the measured optical and physical characteristics of aerosols, an aerosol optical properties model and a radiative transfer model, are examined. Shortwave aerosol radiative forcing (ARF) at the top of the atmosphere (TOA) is < -12 W m( - 2) over Kanpur and Gandhi College. ARF at the surface is ≥ -30 W m( - 2). Atmospheric warming is maximum during premonsoon (>30 W m( - 2)). Shortwave atmospheric heating due to aerosols is >0.4 K/day over IGP and peaks during premonsoon at >0.6 K/day due to lower single scattering albedo (SSA) and higher surface albedo. TOA forcing is always less negative over Kanpur when compared to Gandhi College due to lower surface albedo except in postmonsoon owing to higher SSA. This happens as TOA forcing depends on SSA and surface albedo in addition to aerosol optical depth. The magnitude of longwave forcing and atmospheric cooling in an absolute sense is significantly small and contributes only about 20% or less to the net (shortwave + longwave) forcing. Aerosol radiative effects over these two locations, despite differences in aerosol characteristics, are similar, thus confirming that aerosols and their radiative influence get transported due to circulation. ARF over Kanpur and Gandhi College is an order of magnitude higher when compared to greenhouse gas forcing. A large reduction in surface reaching solar irradiance accompanied by large atmospheric warming can have implications on precipitation and hydrological cycle, and these aerosol radiative effects should be included while performing regional-scale aerosol climate assessments.

An obligatory role for lung infiltrating B cells in the immunopathogenesis of obliterative airway disease induced by antibodies to MHC class I molecules

Using a murine model, we demonstrated that endobronchial administration of antibodies (Abs) to major histocompatibility complex (MHC) class I results in cellular infiltration, epithelial metaplasia, fibrosis and obstruction of the small airways (obliterative airway disease [OAD]) mediated predominantly by Th17 responses to self-antigens. This resembles bronchiolitis obliterans syndrome developed following human lung transplantation. Since B cells play a crucial role in induction of autoimmune responses, we defined the role of B cells and its antigen presenting properties in induction of OAD in this study. Anti-MHC class I was administered endobronchially in B(-/-) and wild-type mice. In contrast to wild type, B(-/-) animals did not demonstrate cellular infiltration, epithelial metaplasia and obstruction of airways following anti-MHC. Frequency of K-α1 tubulin and CollagenV-specific IL-17 cells was significantly decreased in B(-/-) mice. As expected, Abs against self-antigens and germinal center formation were not developed in B(-/-) mice. Thus, we conclude that B cells and its antigen presenting capacity play an important role in induction of immune responses to self-antigens and immunopathogenesis of OAD following the administration of anti-MHC. Therefore, strategies to block B-cell and its antigen presenting functions should be considered for preventing the development of chronic rejection.

A low cost point-of-care viscous sample preparation device for molecular diagnosis in the developing world; an example of microfluidic origami

The lab-on-a-chip concept has led to several point-of-care (POC) diagnostic microfluidic platforms. However, few of these can process raw samples for molecular diagnosis and fewer yet are suited for use in a resource-limited setting without permanent electrical infrastructure. We present here a very low cost paper microfluidic device for POC extraction of bacterial DNA from raw viscous samples--a challenge for conventional microfluidic platforms. This is an example of "microfluidic origami" in that the system is activated by folding; demonstrated here is room temperature cell lysis and DNA extraction from pig mucin (simulating sputum) spiked with E. coli without the use of external power. The microfluidic origami device features dry reagent storage and rehydration of the lysis buffer. We demonstrate DNA extraction from samples with a bacterial load as low as 33 CFU ml(-1). Extraction times, starting from the raw sample, have been optimized to about 1.5 h without the use of external power, or to within 1 h using an oven or a heater block. The fabrication of this paper microfluidic device can be translated into high volume production in the developing world without the need for a semiconductor clean room or a microfabrication facility. The sample preparation can be performed with the addition of just the sample, water, ethanol and elute buffer to the device, thus reducing chemical hazards during transport and handling.

A test of the influence of continental axes of orientation on patterns of human gene flow

The geographic distribution of genetic variation reflects trends in past population migrations and can be used to make inferences about these migrations. It has been proposed that the east-west orientation of the Eurasian landmass facilitated the rapid spread of ancient technological innovations across Eurasia, while the north-south orientation of the Americas led to a slower diffusion of technology there. If the diffusion of technology was accompanied by gene flow, then this hypothesis predicts that genetic differentiation in the Americas along lines of longitude will be greater than that in Eurasia along lines of latitude. We use 678 microsatellite loci from 68 indigenous populations in Eurasia and the Americas to investigate the spatial axes that underlie population-genetic variation. We find that genetic differentiation increases more rapidly along lines of longitude in the Americas than along lines of latitude in Eurasia. Distance along lines of latitude explains a sizeable portion of genetic distance in Eurasia, whereas distance along lines of longitude does not explain a large proportion of Eurasian genetic variation. Genetic differentiation in the Americas occurs along both latitudinal and longitudinal axes and has a greater magnitude than corresponding differentiation in Eurasia, even when adjusting for the lower level of genetic variation in the American populations. These results support the view that continental orientation has influenced migration patterns and has played an important role in determining both the structure of human genetic variation and the distribution and spread of cultural traits.

Remineralization of early enamel lesions using casein phosphopeptide amorphous calcium Phosphate: an ex-vivo study

Objective:

This study aimed at qualitatively evaluating the remineralization potential of casein phosphopeptide amorphous calcium phosphate on artificial early enamel lesions in an ex-vivo scenario by observing the treated tooth surface using a scanning electron microscope (SEM).

Materials and Methods:

This randomized study was conducted on 10 subjects undergoing orthodontic treatment with premolar extraction as part of their treatment. Artificial white lesions were created with the application of 37% phosphoric acid for 20 mins. Teeth were then divided into two groups: one experimental and the other control. Customised orthodontic band with a window was luted with intermediate restorative material in the experimental group whereas in the control group, band without a window was luted. The casein phosphopeptide amorphous calcium phosphate (GC TOOTH MOUSSE) paste was then applied on the window region of the experimental group for 3 mins thrice daily after meals for 14 days, whereas no paste was applied in the control group. After 14 days, teeth were extracted and viewed under an SEM.

Results:

The study groups showed remineralization of the lesions as compared with the control group in most of the samples.

Conclusion:

Casein phophopeptide could significantly remineralize the artificial enamel lesions in vivo.

Effect of 10% sodium ascorbate on the calcium: Phosphorus ratio of enamel bleached with 35% hydrogen peroxide: an in vitro quantitative energy-dispersive X-ray analysis

Objectives:

The study assessed quantitatively the calcium and phosphorous loss from the enamel surface following bleaching with 35% hydrogen peroxide and reversal with 10% sodium ascorbate using energy-dispersive X-ray analysis (EDAX).

Materials and Methods:

Eight non-carious, freshly extracted human permanent maxillary central incisors without any visible defects were used. Each specimen was bleached with 35% hydrogen peroxide activated by light and reversed with sodium ascorbate antioxidant gel. The calcium and phosphorous content in weight percent of sound, bleached and reversed enamel was acquired using EDAX. The Ca/P ratio was calculated from the obtained data. One-way ANOVA followed by Post Hoc Tukey test was used for comparing the Ca/P ratio of sound, bleached and reversed enamel.

Results:

All the samples subjected to bleaching using 35% hydrogen peroxide showed a statistically significant decrease in the Ca/P ratio as compared with samples in which no bleaching procedure was performed (P-value < 0.01). The striking finding was that there was a significant increase in the Ca/P ratio on application of sodium ascorbate antioxidant gel when compared with the bleached enamel (P-value < 0.01).

Conclusion:

The authors concluded that 35% hydrogen peroxide causes a significant decrease in the Ca/P ratio. This decrease in the Ca/P ratio can be restored by the application of 10% sodium ascorbate antioxidant gel.

Antidiabetic and antihyperlipidemic potential of Abelmoschus esculentus (L.) Moench. in streptozotocin-induced diabetic rats

Objectives:

The present investigation was aimed to study the antidiabetic and antihyperlipidemic potential of Abelmoschus esculentus peel and seed powder (AEPP and AESP) in streptozotocin (STZ)-induced diabetic rats.

Materials and Methods:

Acute toxicity of AEPP and AESP was studied in rats at 2000 mg/kg dose and diabetes was induced in rats by administration of STZ (60 mg/kg, i.p.). After 14 days of blood glucose stabilization, diabetic rats received AEPP, AESP, and glibenclamide up to 28 days. The blood samples were collected on day 28 to estimate the hemoglobin (Hb), glycosylated hemoglobin (HbA1c), serum glutamate-pyruvate transferase (SGPT), total protein (TP), and lipid profile levels.

Results:

In acute toxicity study, AESP and AESP did not show any toxicity or death up to a dose of 2000 mg/kg. Therefore, to assess the antidiabetic action, one by fifth and one by tenth dose of both powders were selected. Administration of AEPP and AESP at 100 and 200 mg/kg dose in diabetic rats showed significant (P < 0.001) reduction in blood glucose level and increase in body weight than diabetic control rats. A significant (P < 0.001) increased level of Hb, TP, and decreased level of HbA1c, SGPT were observed after the treatment of both doses of AEPP and AESP. Also, elevated lipid profile levels returned to near normal in diabetic rats after the administration of AEPP and AESP, 100 and 200 mg/kg dose, compared to diabetic control rats.

Conclusion:

The present study results, first time, support the antidiabetic and antihyperlipidemic potential of A. esculentus peel and seed powder in diabetic rats.

Perspectives on human population structure at the cusp of the sequencing era

Human groups show structured levels of genetic similarity as a consequence of factors such as geographical subdivision and genetic drift. Surveying this structure gives us a scientific perspective on human origins, sheds light on evolutionary processes that shape both human adaptation and disease, and is integral to effectively carrying out the mission of global medical genetics and personalized medicine. Surveys of population structure have been ongoing for decades, but in the past three years, single-nucleotide-polymorphism (SNP) array technology has provided unprecedented detail on human population structure at global and regional scales. These studies have confirmed well-known relationships between distantly related populations and uncovered previously unresolvable relationships among closely related human groups. SNPs represent the first dense genome-wide markers, and as such, their analysis has raised many challenges and insights relevant to the study of population genetics with whole-genome sequences. Here we draw on the lessons from these studies to anticipate the directions that will be most fruitful to pursue during the emerging whole-genome sequencing era.

Evaluation of Four Elastomeric Interocclusal Recording Materials

BACKGROUND

The fabrication of dental prosthesis requires the transfer of interocclusal records from patient's mouth to semi-adjustable articulators using different kinds of recording media. Any inaccuracy in these interocclusal records leads to occlusal errors in the final prosthesis. This study was conducted to evaluate the dimensional changes occurring in the interocclusal recording material over a given period of time and the material's resistance to compression during the cast mounting on the articulator.

METHODS

In this in vitro study, the linear dimensional change and compressive resistance of four commercially available elastomeric interocclusal recording media was tested. Three were addition silicones and the fourth was a polyether material. Cylindrical samples of 10mm diameter of each material were prepared in three different thicknesses of 2, 4 and 6mm. Ten samples each of thickness of 2, 4 and 6mm for all four materials were prepared (total of 120 samples). The linear dimensional changes of the samples were evaluated after 24 hours of fabrication. The compressive resistance was measured when each of these was subjected to a constant compressive load of 25 Newtons.

RESULTS

The mean linear dimensional change in a horizontal plane was minimum for Kanibite Hard, an addition silicone. Ramitec showed the maximum linear dimensional change. The mean compression distance was least for Futar D Occlusion (an addition silicone) and maximum for Ramitec (a polyether). It was observed that the samples of thickness 2mm for all the materials underwent least compression.

CONCLUSION

The compressive resistance of each elastomer was inversely proportional to the thickness of the sample. This implies that minimum thickness of the recording materials should be used for recording maxillomandibular relations without sacrificing the strength of the interocclusal record.

Comparison of temperature rise in the pulp chamber with different light curing units: An in-vitro study

Aims/Objectives:

This in vitro study was designed to measure and compare the temperature rise in the pulp chamber with different light curing units.

Materials and Methods:

The study was done in two settings-in-vitro and in-vivo simulation. In in-vitro setting, 3mm and 6mm acrylic spacers with 4mm tip diameter thermocouple was used and six groups were formed according to the light curing source- 3 Quartz-Tungsten-Halogen (QTH) units and 3 Light-Emitting-Diode (LED) units. For the LED units, three modes of curing like pulse-cure mode, fast mode and ramp mode were used. For in-vivo simulation, 12 caries free human third molar tooth with fused root were used. K-type thermocouple with 1 mm tip diameter was used. Occlusal cavity was prepared, etched, rinsed with water and blot dried; bonding agent was applied and incremental curing of composite was done. Thermal emission for each light curing agent was noted.

Results:

Temperature rise was very minimal in LED light cure units than in QTH light cure units in both the settings. Temperature rise was minimal at 6mm distance when compared to 3 mm distance. Among the various modes, fast mode produces the less temperature rise. Temperature rise in all the light curing units was well within the normal range of pulpal physiology.

Conclusion:

Temperature rise caused due to light curing units does not result in irreversible pulpal damage.

Cross-correlated (C2) imaging of fiber and waveguide modes

We demonstrate a method that enables reconstruction of waveguide or fiber modes without assuming any optical properties of the test waveguide. The optical low-coherence interferometric technique accounts for the impact of dispersion on the cross-correlation signal. This approach reveals modal content even at small intermodal delays, thus providing a universally applicable method for determining the modal weights, profiles, relative group-delays and dispersion of all guided or quasi-guided (leaky) modes. Our current implementation allows us to measure delays on a femtosecond time-scale, mode discrimination down to about - 30 dB, and dispersion values as high as 500 ps/nm/km. We expect this technique to be especially useful in testing fundamental mode operation of multi-mode structures, prevalent in high-power fiber lasers.

Dynamics of a polymer chain confined in a membrane

We present a Brownian dynamics theory with full hydrodynamics (Stokesian dynamics) for a Gaussian polymer chain embedded in a liquid membrane which is surrounded by bulk solvent and walls. The mobility tensors are derived in Fourier space for the two geometries, namely, a free membrane embedded in a bulk fluid, and a membrane sandwiched by the two walls. Within the preaveraging approximation, a new expression for the diffusion coefficient of the polymer is obtained for the free-membrane geometry. We also carry out a Rouse normal mode analysis to obtain the relaxation time and the dynamical structure factor. For large polymer size, both quantities show Zimm-like behavior in the free-membrane case, whereas they are Rouse-like for the sandwiched membrane geometry. We use the scaling argument to discuss the effect of excluded-volume interactions on the polymer relaxation time.

Role of SLC5A8, a plasma membrane transporter and a tumor suppressor, in the antitumor activity of dichloroacetate

There has been growing interest among the public and scientists in dichloroacetate as a potential anticancer drug. Credible evidence exists for the antitumor activity of this compound, but high concentrations are needed for significant therapeutic effect. Unfortunately, these high concentrations produce detrimental side effects involving nervous system, thereby precluding its use for cancer treatment. The mechanistic basis of the compound’s antitumor activity is its ability to activate pyruvate dehydrogenase complex through inhibition of pyruvate dehydrogenase kinase. Since the compound inhibits the kinase at micromolar concentrations, it is not known why therapeutically prohibitive high doses are needed for suppression of tumor growth. We hypothesized that lack of effective mechanisms for the entry of dichloroacetate into tumor cells may underlie this phenomenon. Here we show that SLC5A8 transports dichloroacetate very effectively with high affinity. This transporter is expressed in normal cells, but the expression is silenced in tumor cells via epigenetic mechanisms. The lack of the transporter makes tumor cells resistant to the antitumor activity of dichloroacetate. However, if the transporter is expressed in tumor cells ectopically, the cells become sensitive to the drug at low concentrations. This is evident in breast cancer cells, colon cancer cells, and prostate cancer cells. Normal cells, which constitutively express the transporter, are however not affected by the compound, indicating the tumor cell-selective therapeutic activity. The mechanism of the antitumor activity of the compound is still its ability to inhibit pyruvate dehydrogenase kinase and force mitochondrial oxidation of pyruvate. Since the silencing of SLC5A8 in tumors involves DNA methylation and its expression can be induced by treatment with DNA methylation inhibitors, our findings suggest that combining dichloroacetate with a DNA methylation inhibitor would offer a means to reduce the doses of dichloroacetate to avoid detrimental effects associated with high doses but without compromising antitumor activity.

Characterization of HCV-specific CD4+Th17 immunity in recurrent hepatitis C-induced liver allograft fibrosis

Hepatitis C virus (HCV) recurrence with accelerated fibrosis following orthotopic liver transplantation (OLT) is a universal phenomenon. To evaluate mechanisms contributing to HCV induced allograft fibrosis/cirrhosis, we investigated HCV-specific CD4+Th17 cells and their induction in OLT recipients with recurrence utilizing 51 HCV+ OLT recipients, 15 healthy controls and 9 HCV- OLT recipients. Frequency of HCV specific CD4+ Tcells secreting IFN-γ, IL-17 and IL-10 was analyzed by ELISpot. Serum cytokines and chemokines were analyzed by LUMINEX. Recipients with recurrent HCV induced allograft inflammation and fibrosis/cirrhosis demonstrated a significant increase in frequency of HCV specific CD4+Th17 cells. Increased pro-inflammatory mediators (IL-17, IL-1β, IL-6, IL-8 and MCP-1), decreased IFN-γ, and increased IL-4, IL-5 and IL-10 levels were identified. OLT recipients with allograft inflammation and fibrosis/cirrhosis demonstrated increased frequency of Foxp3+ regulatory T cells (Tregs) that inhibited HCV specific CD4+Th1 but not Th17 cells. This suggests that recurrent HCV infection in OLT recipients induces an inflammatory milieu characterized by increased IL-6, IL-1β and decreased IFN-γ which facilitates induction of HCV specific CD4+Th17 cells. These cells are resistant to suppression by Tregs and may mediate an inflammatory cascade leading to cirrhosis in OLT recipients following HCV recurrence.