309 research outputs found
Super-reflection of light from a random amplifying medium with disorder in the complex refractive index : Statistics of fluctuations
The probability distribution of the reflection coefficient for light
reflected from a one-dimensional random amplifying medium with {\it
cross-correlated} spatial disorder in the real and the imaginary parts of the
refractive index is derived using the method of invariant imbedding. The
statistics of fluctuations have been obtained for both the correlated telegraph
noise and the Gaussian white-noise models for the disorder. In both cases, an
enhanced backscattering (super-reflection with reflection coefficient greater
than unity) results because of coherent feedback due to Anderson localization
and coherent amplification in the medium. The results show that the effect of
randomness in the imaginary part of the refractive index on localization and
super-reflection is qualitatively different.Comment: RevTex 6 pages, 3 figures in ps file
Elevated levels of serum sialic acid and C-reactive protein: markers of systemic inflammation in patients with chronic obstructive pulmonary disease
Background: Chronic obstructive pulmonary disease (COPD) is a systemic chronic inflammatory disease with pulmonary and extra-pulmonary manifestations involving lungs causing airways dysfunction. C-reactive protein (C-RP) is a positive acute phase reactant and albumin a negative phase reactant during inflammation in COPD patients. Sialic acid (SA) prevalent in mucus rich tissues is gaining importance as biochemical marker in inflammatory immune response. Purpose of present study was to measure serum C-reactive protein (C-RP), total sialic acid and albumin levels in COPD patients and establish there association in COPD and compare with healthy controls.Methods: Seventy five clinically confirmed COPD patients, both male and female between the age group of 38-70 years were selected for the study and age/ sex matched healthy volunteers as controls were selected for comparison. Serum samples were analyzed for C-RP (mg/dl) by nephalometry and TSA (mmol/L) by periodate resorcinol method and albumin by dye binding method by spectrophotometer.Results: The mean value of serum C-RP in cases was 3.26±2.0 (mg/dl) and in controls 0.57±0.34 (mg/dl) with p<0.001. TSA in cases was 3.53±1.41 (mmol/L) compared to controls 1.81±0.53 (mmol/L), p<0.001. There was a statistically significant positive correlation between C-RP and TSA (r=0.755, p<0.001). The mean value of Albumin in cases decreased (2.54±0.87) as compared to control (4.07±0.66) (p<0.001) showed negative correlation with C-RP (r= -0.418, p<0.01) and TSA (r= -0.728, p<0.001). There was a significant decrease in BMI among cases 19.95±3.17 compared to control 21.17±1.78 p<0.001.Conclusions: C- reactive protein in association with TSA has increased in COPD as a marker of systemic inflammation. Albumin and BMI decreased as a result of nutritional depletion. Patients with low BMI and low serum albumin level have greater risk of having exacerbation, acute respiratory failure than patients with normal BMI.
S-Adenosyl homocysteine and DNA ends stimulate promiscuous nuclease activities in the Type III restriction endonuclease EcoPI
In the absence of the methyl donor S-adenosyl methionine and under certain permissive reaction conditions, EcoPI shows non-specific endonuclease activity. We show here that the cofactor analogue S-adenosyl homocysteine promotes this promiscuous DNA cleavage. Additionally, an extensive exonuclease-like processing of the DNA is also observed that can even result in digestion of non-specific DNA in trans. We suggest a model for how DNA communication events initiating from non-specific sites, and in particular free DNA ends, could produce the observed cleavage patterns
A review on drug resistance patho-mechanisms in ESKAPE bacterial pathogens
The escalating incidence of nosocomial infections stemming from ESKAPE
(Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter
baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) bacterial pathogens presents a
formidable clinical challenge globally, affecting both the developed and developing nations.
These pathogens, which are distinguished by their robust antibiotic resistance mechanisms,
pose a significant threat to the public health. Their ability to evade traditional antimicrobial
treatments underscores the urgent need for novel therapeutic stratifies or alternative
approaches to mitigate their negative impact. Understanding the intricate mechanisms
underpinning antibacterial resistance in ESKAPE bacteria is paramount for developing
effective interventions. Enhanced insights into these mechanisms will facilitate the prediction
of resistance patterns among the multidrug-resistant pathogens, thereby guiding the
development of targeted therapies and preventive measures. Consequently, comprehensive
efforts are needed aiming at unraveling the intricacies of antibacterial resistance in ESKAPE
pathogens that are imperative to safeguarding the public health. The aim of the present review
was to highlight the patho-mechanisms of ESKAPE bacteria towards the different antibiotics
and genes involved in multi-drug resistance
Comparative analysis of co-processed starches prepared by three different methods
Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that co-granulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of co-processing influences the powder and tableting properties of the co-processed excipient
Comparative analysis of co-processed starches prepared by three different methods
Co-processing is currently of interest in the generation of high-functionality excipients for tablet formulation. In the present study, comparative analysis of the powder and tableting properties of three co-processed starches prepared by three different methods was carried out. The co-processed excipients consisting of maize starch (90%), acacia gum (7.5%) and colloidal silicon dioxide (2.5%) were prepared by co-dispersion (SAS-CD), co-fusion (SAS-CF) and co-granulation (SAS-CG). Powder properties of each co-processed excipient were characterized by measuring particle size, flow indices, particle density, dilution potential and lubricant sensitivity ratio. Heckel and Walker models were used to evaluate the compaction behaviour of the three co-processed starches. Tablets were produced with paracetamol as the model drug by direct compression on an eccentric Tablet Press fitted with 12 mm flat-faced punches and compressed at 216 MPa. The tablets were stored at room temperature for 24 h prior to evaluation. The results revealed that co-granulated co-processed excipient (SAS-CG) gave relatively better properties in terms of flow, compressibility, dilution potential, deformation, disintegration, crushing strength and friability. This study has shown that the method of co-processing influences the powder and tableting properties of the co-processed excipient
Reversible and repeatable phase transition at a negative temperature regime for doped and co-doped spin coated mixed valence vanadium oxide thin films
Smooth, uniform mixed valance vanadium oxide (VO) thin films are grown on flexible, transparent Kapton and opaque Al6061 substrates by the spin coating technique at a constant rpm of 3000. Various elements e.g., F, Ti, Mo and W are utilized for doping and co-doping of VO. All the spin coated films are heat treated in a vacuum. Other than the doping elements the existence of only V4+ and V5+ species is noticed in the present films. Transmittance as a function of wavelength and the optical band gap are also investigated for doped and co-doped VO thin films grown on a Kapton substrate. The highest transparency (approximate to 75%) is observed for the Ti, Mo and F (i.e., Ti-Mo-FVO) co-doped VO system while the lowest transparency (approximate to 35%) is observed for the F (i.e., FVO) doped VO system. Thus, the highest optical band gap is estimated as 2.73 eV for Ti-Mo-FVO and the lowest optical band gap (i.e., 2.59 eV) is found for the FVO system. The temperature dependent phase transition characteristics of doped and co-doped VO films on both Kapton and Al6061 are studied by the differential scanning calorimetry (DSC) technique. Reversible and repeatable phase transition is noticed in the range of -24 to -26.3 degrees C
Physiological Correlates of Volunteering
We review research on physiological correlates of volunteering, a neglected but promising research field. Some of these correlates seem to be causal factors influencing volunteering. Volunteers tend to have better physical health, both self-reported and expert-assessed, better mental health, and perform better on cognitive tasks. Research thus far has rarely examined neurological, neurochemical, hormonal, and genetic correlates of volunteering to any significant extent, especially controlling for other factors as potential confounds. Evolutionary theory and behavioral genetic research suggest the importance of such physiological factors in humans. Basically, many aspects of social relationships and social activities have effects on health (e.g., Newman and Roberts 2013; Uchino 2004), as the widely used biopsychosocial (BPS) model suggests (Institute of Medicine 2001). Studies of formal volunteering (FV), charitable giving, and altruistic behavior suggest that physiological characteristics are related to volunteering, including specific genes (such as oxytocin receptor [OXTR] genes, Arginine vasopressin receptor [AVPR] genes, dopamine D4 receptor [DRD4] genes, and 5-HTTLPR). We recommend that future research on physiological factors be extended to non-Western populations, focusing specifically on volunteering, and differentiating between different forms and types of volunteering and civic participation
Prognosticfactors in patients with renal cell carcinoma: Is TNM (1997) staging relevant in Indian subpopulation?
BACKGROUND: RCC (Renal Cell Carcinoma) is a common genitourinary
malignancy, but its behavior has not been studied in the Indian
Subpopulation. AIMS: The aim of this study was to assess the validity
of 1997 AJCC TNM staging in Indian subpopulation and also to identify
independent predictors for survival in patients having RCC. SETTING
AND DESIGN: Retrospective uncontrolled analysis of patients with RCC
was performed at our centre. MATERIAL AND METHODS: Medical records of
patients of undergoing radical nephrectomy at our center between 1994
to August 2003 were identified retrospectively. Medical records of 178
patients were available for analysis. Patient characteristics,
preoperative imaging and surgical details were reviewed. Each tumor was
staged according to the 1997 AJCC TNM classification. Nuclear grade was
assigned according to the Fuhrman\u2032s grading system. STATISTICAL
METHODS: Statistical analysis was performed using statistical software
and descriptive statistics and survival functions were obtained.
Univariate and multivariate analysis of factors affecting outcome of
the patient were performed. RESULTS: Mean follow up period was 42.3
months (range 3 to 108 months). Stage wise 5-year Cancer specific
survival was 87.2% in stage 1 disease, 74.3% in stage 2, 36.4% in stage
3 and 3.1% in stage 4. Univariate analysis revealed that stage, grade
and lymph node status were statistically significant (P=0.009, 0.007
and 0.003 respectively). Sub-classifying stage 1 tumors between tumor
of less than 4 cm. and more than 4 cm. did not reveal any statistically
significant difference in survival (P=0.32). Multivariate analysis
model revealed that Fuhrman\u2032s grade and lymph node status were
statistically significant (P=0.007 and 0.002 respectively).
CONCLUSION: This study validates the TNM (1997) staging for RCC as
having significant survival impact in the Indian subpopulation.
Sub-classifying stage 1 tumors between tumor of less than 4 cm. and
more than 4 cm is not of much importance. Nuclear grade and lymph node
involvement are important independent predictors of survival. Organ
confined tumors with high nuclear grades need to be followed up more
rigorously
Calibration of VELC detectors on-board Aditya-L1 mission
Aditya-L1 is the first Indian space mission to explore the Sun and solar
atmosphere with seven multi-wavelength payloads, with Visible Emission Line
Coronagraph (VELC) being the prime payload. It is an internally occulted
coronagraph with four channels to image the Sun at 5000 \AA~ in the field of
view 1.05 - 3 \rsun, and to pursue spectroscopy at 5303 \AA, 7892 \AA~ and
10747 \AA~ channels in the FOV (1.05 - 1.5 \rsun). In addition,
spectropolarimetry is planned at 10747 \AA~ channel. Therefore, VELC has three
sCMOS detectors and one InGaAs detector. In this article, we aim to describe
the technical details and specifications of the detectors achieved by way of
thermo-vacuum calibration at the CREST campus of the Indian Institute of
Astrophysics, Bangalore, India. Furthermore, we report the estimated conversion
gain, full-well capacity, and readout noise at different temperatures. Based on
the numbers, it is thus concluded that it is essential to operate the sCMOS
detectors and InGaAs detectors at and C,
respectively, at the spacecraft level.Comment: Accepted for publication in Experimental Astronomy; 13 Pages, 5
Figures and 8 Table
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