Assessment Of Preventive Dental Care Among Dental Students In India: A Knowledge, Attitude, And Education Study

Aim: Knowledge and oral health behavior of dental students plays an important role in oral health education of patients and community at large. It is therefore important that their own oral health behavior conforms to expectations of the population. Hence, the aim of the present study was to evaluate the oral health knowledge, attitude, and education among dental students. Materials and Methods: In the present study an online survey was distributed to 1500 dental students from eight dental colleges in India The participants were divided into two groups – final years and interns. Data collected was statistically analyzed Kruskal-Wallis test was used for intergroup comparison and Mann-Whitney test was used for intragroup comparison. Result: There was no statistical difference in knowledge between both groups, though a statistically significant difference was seen between the groups for attitude and practice Conclusion: The results of our study show that students who participated in the study have good knowledge about the preventive dental treatment. However they should be encouraged to practice what they have learnt and encouraged to do more preventive treatment along with curative treatment

Evaluation Of Knowledge, Attitude and Practice Of Pediatricians Towards Long-Term Liquid Medicaments And Its Association With Dental Health

Background: A regular practice following child birth is interaction with the pediatrician for routine medical examination, who administers children with a variety of medicines. Heavily sweetened liquid pediatric medicines has been a well accepted risk factor for the development of dental caries and dental erosion. Aim: To evaluate pediatricians' knowledge, attitude and practice about the long term use of liquid pediatric medicines and their relationship with dental caries and dental erosion. Methods: A cross-sectional survey was undertaken among the pediatricians in Chennai. Total subjects included in the survey were 55 pediatricians, through the method of convenience sampling. Data was collected by pre-tested, structured and self administered questionnaires handed out in hospitals, medical clinics and offices. The data on qualitative responses of the respondents was presented in percentage and statistical significance was tested using Chi-square test for independence of attributes. Results: No statistical difference was seen in the practice of advising dental checkup. Statistically significant difference was seen in awareness of PLM and association with caries, Prescription time for PLM, Practice on advising of rinsing mouth with water, brushing and chewing gum (P<0.001) Conclusion: Pediatricians in this study did not adequately perceive the relationship between the presence of fermentable carbohydrates in pediatric liquid medications and dental caries. But, they had moderate knowledge and lacked proper attitude and practice regarding the various preventive measures . Further studies with a larger sample are necessary

SiGe based multiple-phase VCO operating for mm-wave frequencies

The ever-increasing demand for higher speed in wireless consumer applications has increased the interest in the unlicensed spectrum of 7 GHz around 60 GHz. The high atmospheric oxygen absorption at 60 GHz and small size of the antennas at this frequency requires the use of integrated phased-array systems to overcome the deficiencies of lossy channels at these frequencies. The phased arrays combine signals from multiple paths to obtain higher receiver sensitivity and directivity. The system thus requires phase-shifted voltage-controlled oscillator (VCO) signals to implement phase shifting in the local-oscillator (LO) path. In this research, the vector sum method to generate various phases of the signal at 60 GHz was investigated for its suitability in phased-array systems. The main focus was on improving the phase noise performance of the VCO. The VCO was implemented using a fully differential common-collector Colpitts oscillator in the cascode configuration, which was found to be the VCO configuration with acceptable phase noise performance and stability in the millimetre-wave range. The research focus was on modelling the phase noise of the VCO, and was performed by identifying the impulse sensitivity function for various noise sources, followed by analysing its effect on the linear time varying (LTV) model of the oscillators. The analysis led to a closed-form expression for the phase noise of the oscillator in terms of process and design parameters. The design was then optimised in terms of identified parameters to attain minimum phase noise. The phase noise expression using LTV theory and SpectreRF simulations reported the same optimum value for the design parameter, of around 0.3 for the capacitor ratio. The simulation results utilising the vector sum phase shifting method to generate multiple phase oscillator signals suggest its suitability in implementing phased-array systems in the millimetre-wave range. The vector sum was realised by generating quadrature signals from the oscillator using hybrid couplers. Variable gain amplifiers (VGAs) based on Gilbert mixer topology were used to combine the in-phase and quadrature phase signals to generate the phase-shifted oscillator signal. The gains of the VGAs were linearised by using a pre-distortion circuit, which was an inverse tanh cell. A fully differential 60 GHz VCO was fabricated using a SiGe process with a fT of 200 GHz. The fabricated integrated circuit (IC) measured at the wafer level had a centre frequency of 52.8 GHz and a tuning range of 7 GHz. It demonstrated a phase noise performance of -98.9 dBc/Hz at 1 MHz offset and a power dissipation of 140 mW, thus providing a VCO figure of merit of 172 dBc/Hz. It delivered a differential output power of 8 dBm and the IC occupied an area of 0.54 mm2, including the bondpads. It was thus concluded that a 10 % design margin for the tuning range is required while using SiGe BiCMOS technology. The simulation results demonstrate that the VCO, along with an active interpolator, provides a range of phase-shifted signals from 0° to 360° in steps of 22.5° for various gain settings of the VGAs. The power dissipation of the active interpolator is around 60 mW and the system could thus be employed in LO path shifting architecture of the phased arrays with increased power consumption.Thesis (PhD)--University of Pretoria, 2013.Electrical, Electronic and Computer Engineeringunrestricte

Phase noise analysis for a mm-wave VCO configuration

The letter highlights the importance of modelling the phase noise of an oscillator using the impulse sensitivity function. A Colpitts oscillator in the common collector configuration is analyzed to obtain an expression for its phase noise. The oscillator design is thus optimized for phase noise with respect to process and design parameters. The fabricated voltage controlled oscillator at an oscillating frequency of 52.8 GHz has a measured phase noise of -98.9 dBc/Hz at 1 MHz offset.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1098-2760hb201

BiCMOS Colpitts oscillator for vector-sum interpolators

PURPOSE : The demand for higher bandwidth has resulted in the development of mm-wave phased array systems. This paper explores a technique that could be used to feed the individual antennas in a mm-wave phased array system with the appropriate phase shifted signal, to achieve required directivity. It presents differential Colpitts oscillators at 5 GHz and 60 GHz that can provide differential output signals to quadrature signal generators in the proposed phase shifter system. APPROACH : The phase shifter system comprises a differential Colpitts voltage controlled oscillator (VCO) and utilizes the vector-sum technique to generate the phase shifted signal. The differential VCO is connected in the common-collector configuration for the 5 GHz VCO, and is extended using a cascode transistor for the 60 GHz VCO for better stability at mm-wave. The vector-sum is achieved using a variable gain amplifier (VGA) that combines the in-phase and quadrature phase signal, generated from oscillator output using hybrid Lange couplers. The devices were fabricated using IBM 130 nm SiGe BiCMOS process, and simulations were performed with a process design kit provided by the foundry. FINDINGS : The measured results of the 5 GHz and 60 GHz VCOs indicate that differential Colpitts VCO could generate oscillator output with good phase noise performance. The simulation results of the phase shifter system indicate that generation of signals with phases from 0° to 360° in steps of 22.5° was achieved using the proposed approach. A Gilbert mixer topology was used for the VGA and the linearity was improved by a pre-distortion circuit implemented using an inverse tanh cell. ORIGINALITY / VALUE : The measurement results indicate that differential Colpitts oscillator in common-collector configuration could be used to generate differential VCO signals for the vector-sum phase shifter. The simulation results of the proposed phase shifter system at mm-wave shows that the phase shift could be realised at a total power consumption of 200 mW.http://www.emeraldinsight.com/loi/mihb2016Electrical, Electronic and Computer Engineerin

A role for the Hsp90 molecular chaperone family in antigen presentation to T lymphocytes via major histocompatibility complex class II molecules

The heat shock protein (HSP) Hsp90 is known to chaperone cytosolic peptides for MHC class I (MHCI)-restricted antigen presentation to T lymphocytes. We now demonstrate a role for Hsp90 activity in presentation of antigens on MHCII. Treatment of mouse antigen-presenting cells (APC) with the pharmacological Hsp90 inhibitor, geldanamycin, inhibited MHCII-mediated presentation of endocytosed and cytosolic proteins as well as synthetic peptides to specific T cells. Ectopic expression of human Hsp90 in APC enhanced MHCII-mediated antigen presentation. Further, pharmacological Hsp90 inhibition reduced, while retroviral Hsp90 overexpression enhanced, the levels of stable compact MHCII heterodimers correlating with the antigen presentation phenotype. Pharmacological inhibition of Hsp90 activity in IFN-γ-treated APC resulted in severe abrogation of MHCII-restricted presentation of cytosolic antigen, but only partially inhibited exogenous antigen presentation. Our data suggest a major role for Hsp90 activity in MHCII-mediated antigen presentation pathways, and implicate IFN-γ-inducible Hsp90-independent mechanisms

Cardiac monitoring in memory clinics: national survey of UK practice

Aims and method People diagnosed with dementia are often started on acetylcholinesterase inhibitors (AChEIs). As AChEIs can be associated with cardiac side-effects, an electrocardiogram (ECG) is sometimes requested before treatment. Previous work has suggested there is little consensus as to when or how ECGs should be obtained. This can create inconsistent practice, with patient safety, economic and practical repercussions. We surveyed 305 UK memory clinic practitioners about prescribing practice. Results More than 84% of respondents completed a pulse and cardiac history before prescribing AChEIs. Opinion was divided as to who should fund and conduct ECGs. It was believed that obtaining an ECG causes patients inconvenience and delays treatment. Despite regularly interpreting ECGs, 76% of respondents did not update this clinical skill regularly. Clinical implications The variation in practice observed has service-level and patient implications and raises potential patient safety concerns. Implementing national guidelines or seeking novel ways of conducting cardiac monitoring could help standardise practice

Associations between frailty, physical performance, and renal biomarkers in older people with advanced chronic kidney disease

Acknowledgments With thanks to the recruiting teams and participants who took part in the BiCARB trial. GS and MDW acknowledge support from the NIHR Newcastle Biomedical Research CentrePeer reviewedPublisher PD

Mimicry of native peptide antigens by the corresponding retro-inverso analogs is dependent on their intrinsic structure and interaction propensities

Retro-inverso (ri) analogs of model T cell and B cell epitopes were predictively designed as mimics and then assayed for activity to understand the basis of functional ri-antigenic peptide mimicry. ri versions of two MHC class I binding peptide epitopes, one from a vesicular stomatitis virus glycoprotein (VSVp) and another from OVA (OVAp), exhibit structural as well as functional mimicry of their native counterparts. The two ri peptides exhibit conformational plasticity and they bind to MHC class I (H-2Kb) similar to their native counterparts both in silico and in vivo. In fact, ri-OVAp is also presented to an OVAp-specific T cell line in a mode similar to native OVAp. In contrast, the ri version of an immunodominant B cell peptide epitope from a hepatitis B virus protein, PS1, exhibits no structural or functional correlation with its native counterpart. PS1 and its ri analog do not exhibit similar conformational propensities. PS1 is less flexible relative to its ri version. These observed structure-function relationships of the ri-peptide epitopes are consistent with the differences in recognition properties between peptide-MHC vs peptide-Ab binding where, while the recognition of the epitope by MHC is pattern based, the exquisitely specific recognition of Ag by Ab arises from the high complementarity between the Ag and the binding site of the Ab. It is evident that the correlation of conformational and interaction propensities of native L-peptides and their ri counterparts depends both on their inherent structural properties and on their mode of recognition