2,762 research outputs found
Inflaton Decay in an Alpha Vacuum
We study the alpha vacua of de Sitter space by considering the decay rate of
the inflaton field coupled to a scalar field placed in an alpha vacuum. We find
an {\em alpha dependent} Bose enhancement relative to the Bunch-Davies vacuum
and, surprisingly, no non-renormalizable divergences. We also consider a
modified alpha dependent time ordering prescription for the Feynman propagator
and show that it leads to an alpha independent result. This result suggests
that it may be possible to calculate in any alpha vacuum if we employ the
appropriate causality preserving prescription.Comment: 16 pages, 1 figure, Revtex 4 preprin
INFLUENCE OF FOOT TYPE ON BALANCE AND POSTURAL SWAY AMONG THE COMMUNITY DWELLING OLDER ADULTSâ€
Aim: To compare the relationship between Foot Type, Postural sway and Balance among the community dwelling older adult.Objective: 1. To find the correlation between foot type on static and dynamic balance among community dwelling older adults2.To find the correlation between postural sway and foot type among community dwelling older adults.Methodology: 20 community dwelling older adults were included for the study based on inclusion and exclusion criteria. The subjects foot type was assessed using the navicular drop test. The subjects were classified into 3 different foot types: as pronated, neutral and supinated. After classifying the subject according to the foot type, they were measured for static and dynamic balance using Berg Balance Scale(BBS). For the same subjects, postural sway was assessed with Lord's Sway meter under 4 situations: 1. Standing on stable surface(floor) open eyes and 2. Standing on stable surface(floor) closed eyes, 3. Standing on unstable surface(foam) with eyes open and 4. Standing on unstable surface(foam) with eyes closed. The sway of older adult was recorded and analysedResult: There was strong correlation between pronated and anteroposterior sway in EO on unstable surface and between neutral and anteroposterior sway in EC standing on stable surface. There was moderate correlation between berg balance scale score and neutral foot type. Pronated and anteroposterior sway in EO standing on stable surface also showed moderate correlation.Conclusion: The results showed strong to moderate correlation between foot type, postural sway and balance, from this study it is clear that foot position affects the balance among older adults. Â
Progressive myoclonic epilepsy due to rare mitochondrial ND6 mutation, m.14487T>C
INTRODUCTION:
Mitochondrial diseases exhibit wide phenotypic heterogeneity, and can present as progressive myoclonic epilepsy.
SUMMARY:
We report a case of adult-onset drug-resistant epilepsy, cortical myoclonus and bilateral optic neuropathies due to m.14487T>C, a rare mitochondrial gene mutation identified on whole-genome sequencing. This mutation, which affects the NADH dehydrogenase 6 (ND6) subunit of the mitochondrial respiratory chain, is most commonly implicated in cases of infantile-onset Leigh syndrome, although a broader phenotypic spectrum including migraine with aura and progressive myoclonic epilepsy have been described. Serial MRI scans over a 2-year period demonstrated the interval development of bihemispheric stroke-like lesions. Giant somatosensory evoked potentials and short-duration myoclonic jerks with craniocaudal spread on surface electromyography were consistent with cortical myoclonus. Optical coherence tomography showed bilateral symmetric thinning of the nerve fibre layer in the papillomacular bundles.
CONCLUSION:
Whole-genome sequencing can help to provide a definitive diagnosis for mitochondrial disease and should be considered in situations where clinical suspicion remains high despite normal genetic panels or muscle histopathology. Mitochondrial disease can present as adult-onset progressive myoclonic epilepsy, and bilateral optic neuropathies can be a striking feature of ND6 mitochondrial gene mutations. In our case, severe cortical myoclonus affecting speech and swallowing remained highly drug-resistant, however, symptomatic benefit was derived from targeted onabotulinum toxin A injections
Mechanism of phosphorescence quenching in photomagnetic molecules determined by positron annihilation spectroscopy
Platinum Octaethyl Porphyrin (Pt.OEP) is an efficient phosphor under ultraviolet excitation. The phosphorescent triplet state (T(sub 1)) is readily quenched by the oxygen (O2) molecules. This phenomenon is being utilized as the basis for global air pressure measurements in aerodynamic facilities at various laboratories. The exact mechanism by which O2 molecules quench the (T(sub 1)-S(sub 0)) transitions is still unknown. The diamagnetic S(sub n) singlet states, which feed T(sub 1) states via intersystem crossings, would presumably not be affected by O2. It must be the magnetic T(sub 1) states, which can interact with the paramagnetic O2 molecules, that are affected. However, our positron lifetime and Doppler broadening studies suggest the formation of (S(sub n).02) complexes which can also eventually reduce the population of the T(sub 1) states (i.e. quench phosphorescence). This is possible since higher triplet states in (Pt-OEP) are admixed with the S(sub n) states via spin orbit interactions. The experimental procedures and the results of various measurements are discussed in this paper
Mechanism of phosphorescence quenching in photomagnetic molecules determined by positron annihilation spectroscopy
Platinum Octaethyl Porphyrin (Pt.OEP) is an efficient phosphor under ultraviolet excitation. The phosphorescent triplet state (T(sub 1)) is readily quenched by the oxygen (O2) molecules. This phenomenon is being utilized as the basis for global air pressure measurements in aerodynamic facilities at various laboratories. The exact mechanism by which O2 molecules quench the (T(sub 1) - S(sub 0)) transitions is still unknown. The diamagnetic S(sub n) singlet states, which feed T(sub 1) states via intersystem crossings, would presumably not be affected by O2. It must be the magnetic T(sub 1) states, which can interact with the paramagnetic O2 molecules, that are affected. However, our positron lifetime and Doppler broadening studies suggest the formation of (S(sub n) central dot O2) complexes which can also eventually reduce the population of the T(sub 1) states (i.e. quench phosphorescence). This is possible since higher triplet states in (Pt.OEP) are admixed with the S(sub n) states via spin orbit interactions. The experimental procedures and the results of various measurements are discussed in this paper
FORMULATION AND EVALUATION OF SIMVASTATIN GASTRORETENTIVE DRUG DELIVERY SYSTEM
Objective: The aim of this study was to formulate and evaluate gastro retentive drug delivery system (GRRDS) using an effervescent approach for simvastatin.Methods: Floating tablets were prepared using directly compressible polymers hydroxypropyl methylcellulose (HPMC) K100M, HPMC K4M and carboxymethylcellulose sodium (NaCMC). The prepared tablets were subjected to pre-formulation studies like Compressibility index, Hausner ratio and post compression parameters like buoyancy/floating test and In vitro dissolution study.Results: Drug-excipient compatibility studies performed with the help of FTIR instrument indicated that there were no interactions. The DSC thermogram of the formulations revealed that crystalline form of simvastatin existed in the formulation which was confirmed by X-ray powder diffraction. Dissolution studies indicated that there was a decrease in the drug release with an increase in the polymer viscosity. The tablets prepared with low-viscosity grade HPMC K4M exhibited short Buoyancy Lag Time and floated for a longer duration as compared with formulations containing high viscosity grade HPMC K100M. The ‘n' value for dissolution studies for all the formulations was found to be in the range of 0.647 to 0.975 indicating non-Fickian or anomalous drug transport. Conclusion: The drug release rate and floating duration of tablets depended on the nature of the polymer and other added excipients. The release rate of the drug can be optimized by using different ratios of polymers and other excipients. The formulation F8 achieved the optimized batch and complied with all the properties of the tablets
Effect of Milk on Fibronectin and Collagen Type I Binding to \u3ci\u3eStaphylococcus aureus\u3c/i\u3e and Coagulase-Negative Staphylococci Isolated from Bovine Mastitis
Tryptic soy broth (TSB)-grown cells of Staphylococcus aureus isolated from acute and chronic bovine mastitis bound mainly 125I-fibronectin (125I-Fn), whereas strains of nine species of coagulase-negative staphylococci showed a predominant interaction with 125I-collagen (125I-Cn) type I. A particle agglutination assay (PAA) was used to examine the interaction of coagulase-negative staphylococci with 1251-Fn and 125I-Cn immobilized on latex. All 368 coagulase-negative staphylococci demonstrated high 125I-Cn and moderate to low 125I-Fn interactions in the PAA. Cn-PAA reactivity was high among strains of Staphylococcus xylosus (84.2%), Staphylococcus simulans (77.8%), Staphylococcus epidermidis (76.7%), and Staphylococcus hyicus (74.3%), whereas all six Staphylococcus capitis strains clumped Cn-PAA reagent. Incubating TSB-grown cells in 10% skim milk for 1 h decreased the 125I-Fn- and 125I-Cn-binding affinity in most of the S. aureus and coagulase-negative staphylococci, while growth in 10% skim milk for 18 h resulted in more than 90% decrease or complete loss of interaction with these proteins. Decreased 1251-Fn binding in the presence of milk was correlated with protease production but not with 125I-Cn binding
Effect of Milk on Fibronectin and Collagen Type I Binding to \u3ci\u3eStaphylococcus aureus\u3c/i\u3e and Coagulase-Negative Staphylococci Isolated from Bovine Mastitis
Tryptic soy broth (TSB)-grown cells of Staphylococcus aureus isolated from acute and chronic bovine mastitis bound mainly 125I-fibronectin (125I-Fn), whereas strains of nine species of coagulase-negative staphylococci showed a predominant interaction with 125I-collagen (125I-Cn) type I. A particle agglutination assay (PAA) was used to examine the interaction of coagulase-negative staphylococci with 1251-Fn and 125I-Cn immobilized on latex. All 368 coagulase-negative staphylococci demonstrated high 125I-Cn and moderate to low 125I-Fn interactions in the PAA. Cn-PAA reactivity was high among strains of Staphylococcus xylosus (84.2%), Staphylococcus simulans (77.8%), Staphylococcus epidermidis (76.7%), and Staphylococcus hyicus (74.3%), whereas all six Staphylococcus capitis strains clumped Cn-PAA reagent. Incubating TSB-grown cells in 10% skim milk for 1 h decreased the 125I-Fn- and 125I-Cn-binding affinity in most of the S. aureus and coagulase-negative staphylococci, while growth in 10% skim milk for 18 h resulted in more than 90% decrease or complete loss of interaction with these proteins. Decreased 1251-Fn binding in the presence of milk was correlated with protease production but not with 125I-Cn binding
Timing Offset Calibration of CZTI instrument aboard ASTROSAT
The radio as well as the high energy emission mechanism in pulsars is yet not
understood properly. A multi-wavelength study is likely to help in better
understanding of such processes. The first Indian space-based observatory,
ASTROSAT, has five instruments aboard, which cover the electromagnetic spectrum
from infra-red (1300 ) to hard X-ray (380 KeV). Cadmium Zinc Telluride
Imager (CZTI), one of the five instruments is a hard X-ray telescope functional
over an energy range of 20-380 KeV. We aim to estimate the timing offset
introduced in the data acquisition pipeline of the instrument, which will help
in time alignment of high energy time series with those from two other
ground-based observatories, viz. the Giant Meterwave Radio Telescope (GMRT) and
the Ooty Radio Telescope (ORT). PSR B0531+21 is a well-studied pulsar with
nearly aligned radio and hard X-ray pulse profiles. We use simultaneous
observations of this pulsar with the ASTROSAT, the ORT and the GMRT. The pulsar
was especially observed using the ORT with almost daily cadence to obtain good
timing solutions. We also supplement the ORT data with archival FERMI data for
estimation of timing noise. The timing offset of ASTROSAT instruments was
estimated from fits to arrival time data at the ASTROSAT and the radio
observatories. We estimate the offset between the GMRT and the ASTROSAT-CZTI to
be -4716 50 . The corresponding offset with the ORT was -29639
50 . The offsets between the GMRT and Fermi-LAT -5368 56
. (Abridged)Comment: 6 pages, 5 figures, 2 tables, Revised and Updated, accepted for
publication in A&
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