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In this article, an extremely wideband, isolation-enhanced, low-profile “Multiple-Input-Multiple-Output” (MIMO) antenna along with dual-band-notched features has been investigated. The antenna proposed herein, possesses two mutually orthogonal staircase-etched radiators for achieving a wide bandwidth. The radiating elements are placed mutually perpendicular in order to achieve polarization diversity and high isolation, i.e. for minimization of mutual coupling effect between adjacent radiating elements. The antenna exhibits an extremely wide frequency bandwidth covering 1.2–19.4 GHz except two frequency band notches centered at 3.5 and 5.5 GHz, respectively, originated due to the incorporation of a “Rectangular Complementary Split Ring Resonator (RCSRR)” structure and by etching dual “L-shaped” slits in the ground plane. The center frequency of the notched bands is adjusted by fine tuning of the dimensions of the incorporated band-notching structures. Isolation level (S21) better than −20 dB has been obtained due to the insertion of a “T-shaped” parasitic element as a decoupling structure. A prototype of the proposed antenna having dimension of 20 mm × 20 mm (0.08 λo × 0.08 λo) is fabricated and the antenna responses have been measured. Obtained results show that the miniaturized MIMO diversity antenna is undoubtedly a capable contender for communications supporting an extremely wide impedance bandwidth along with band-notched features for WLAN and WiMAX.
Crab Pulsar (PSR B0531+21) is known to emit pulsed emission in all bands of the electromagnetic spectrum. It also emits giant radio pulses (GRPs) frequently, which are roughly a hundred to million times brighter than the normal pulses. We aim to study whether there is a significant X-ray enhancement correlated with the occurrence of GRPs, using simultaneous observations with the ASTROSAT, the Giant Meterwave Radio telescope (1300 MHz) and the Ooty Radio telescope (325 MHz). This required determination of fixed pipeline offsets between different instruments. We find the offset between ASTROSAT and GMRT to be −30.181 ± 0.095 ms and that between ASTROSAT and ORT to be −18.4 ± 0.2 ms. Our preliminary results with 1300 MHz data also show a break in pulse intensity distribution at ~ 33 Jy in the main pulse and ~ 28 Jy in the inter-pulse.
Chickens (Gallus gallus) were the first avian species selected for whole genome sequencing because of their economic value, use as a food source, livelihood security and research importance. Any living organism contains a galaxy of genes which express all the phenotypes or characters by encoding proteins and peptides, and playing regulatory roles in the biological system. Functional genomics in turn, is a multidisciplinary approach to identify and demonstrate the functional roles of genes and other regulatory molecules such as microRNA and CpG methylation in biological pathways. In the last two decades, the chicken genome database has made significant advancements in accruing large amounts of genomic information through employing advanced bio-informatic tools. Several techniques such as cDNA microarray, serial analysis of gene expression, massively parallel signature sequencing, cDNA subtractive hybridisation and next generation sequencing have been utilised to investigate the genome-wide expression profile instead of revealing expression pattern of one or a few genes in various avian species. Expressed sequence tag or cDNA sequences are the key factors for identification of novel genes and understanding the complex molecular cascades of ontology. A large-scale cDNA library has been constructed from embryonic and adult tissues and consequently identified the presence of about 19,000 functional genes in chickens. The micro RNAs play crucial role in gene expression and to date, approximately 496 micro RNAs have been characterised. The non-coding RNA alters gene expression involved in cellular process, by modulating the chromatin architecture, transcription, RNA splicing, editing, translation and turnover. Functional genomics studies have been extensively used to identify genes associated with several production traits, immuno-genetic mechanism, host-pathogen interaction, pathogen biology etc. Nutrigenomics have determined the genomic mechanism involved in feed utilisation, metabolism and cholesterol synthesis etc., which ultimately reveal potential applications for improving the nutritional efficiency of birds. This review discusses the tools and utility of functional genomics approaches in chicken.
Due to the high surface area and good bio-compatibility of nano structured ZnO, it finds good utility in biosensor applications. In this work we have fabricated highly dense ZnO nano bundles with the assistance of self assembled poly methylsilisesquoxane (PMSSQ) matrix which has been realized in a carpet like configuration with implanted ZnO nano-seeds. Such high aspect ratio structures (∼50) with carpet like layout have been realized for the first time using solution chemistry. Nanoparticles of PMMSQ are mixed with a nano-assembler Poly-propylene glycol (PPG) and Zinc Oxide nanoseeds (5-15 nm). The PPG acts by assembling the PMSSQ nanoparticles and evaporates from this film thus creating the highly porous nano-assembly of PMMSQ nanoparticles with implanted Zinc Oxide seeds. Nano-wire bundles with a high overall surface roughness are grown over this template by a daylong incubation of an aqueous solution of hexamethylene tetra amine and Zinc nitrate. Characterization of the fabricated structures has been extensively performed using FESEM, EDAX, and XRD. We envision these films to have potential of highly dense immobilization platforms for antibodies in immunosensors. The principle advantage in our case is a high aspect ratio of the nano-bundles and a high level of roughness in overall surface topology of the carpet outgrowing the zinc-oxide nanowire bundles. Antibody immobilization has been performed by modifying the surface with protein-G followed by Goat anti salmonella antibody. Antibody activity has been characterized by using 3D profiler, Bio-Rad Protein assay and UV-Visible spectrophotometer.
Synthesis of FeC2O42H2O nano particles was carried out by thermal double decomposition of solutions of oxalic acid dihydrate (C2H2O4 2H2O) and FeSO4 7H2O employing CATA -2R microwave reactor. Structural elucidation was carried out by employing X-ray diffraction, particle size and shape were studied by transmission electron microscopy and nature of bonding was investigated by Optical absorption and near-infrared spectral studies. The powder resulting from this method is possesses distorted rhombic octahedral structure. The particle grain size is about 50 nm. Details of optical transitions are mentioned in terms of energy states.
Graphite electrode surface degradation mechanisms and formation of solid electrolyte layers (SEI) at the interface with the electrolyte were studied as a function of the applied voltage and voltage scan rates using in situ optical microscopy. Voltammetry tests were initiated from a peak voltage of 3.00 V during which the voltage was decreased to a constant base potential (0.02 V) using different scan rates of 0.05-5.00 mV/s. Cross-sectional FIB microscopy indicated that graphite surface and subsurface damage -- in the form of loss of material from graphite -- was reduced when dense and continuous deposits of SEI formed at low scan rates (e.g. 0.05 mV/s).Whereas, non-uniform and discontinuous SEI formed at high scan rates (∼ 5.00 mV/s) was unable to alleviate graphite surface damage.
Pulsed Electron Deposition (PED) is an attractive alternative to Pulsed Laser Deposition (PLD) for growing high temperature superconductor thin films because of its relatively low cost. In this study, YBa2Cu3O7-δ(YBCO) thin film has been fabricated on silicon substrates by Pulsed Electron Deposition technique. SrTiO3 (STO) as a buffer layer has been grown between Si substrate and YBCO superconducting layer. The crystalline structures of STO/Si and YBCO/STO/Si films have been investigated by x-ray diffraction (XRD). The surface morphology and microstructure of YBCO/STO/Si thin film have been characterized with atomic force microscope (AFM) and scanning electron microscope (SEM). From the θ-2θ XRD analysis of YBCO thin films, (00l) diffraction peaks are obtained indicating they have a poor c-axis oriented structure. SEM analysis shows that the surfaces of films are crack-free, but they have some particulates. On AFM images, the droplets are clearly observed leading to a roughly surface.
Prior to 2009 dengue fever had not been reported in the Andaman and Nicobar archipelago. In 2009, a few patients with dengue fever-like illness were reported, some of whom tested positive for dengue antibodies. In 2010, 516 suspected cases were reported, including some with dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS); 80 (15·5%) were positive for dengue antibodies. DENV RNA was detected in five patients and PCR-based typing showed that three of these belonged to serotype 1 and two to serotype 2. This was confirmed by sequence typing. Two clones of dengue virus, one belonging to serotype 1 and the other to serotype 2 appeared to be circulating in Andaman. Emergence of severe diseases such as DHF and DSS might be due to recent introduction of a more virulent strain or because of the enhancing effect of sub-neutralizing levels of antibodies developed due to prior infections. There is a need to revise the vector-borne disease surveillance system in the islands.
ZnSe nanorods are grown by varying the amount of reducing agent Sodium
borohydride and keeping the amount of zinc chloride, selenium powder
constant. The samples are characterized using electron diffraction
techniques. Simultaneously optical absorption, photoluminescence and
longtime photorelaxation of these samples are studied at room temperature.
An increase in band gap is observed in each case as compared to bulk ZnSe.
Also the formation of nanorods is found to be favourable at particular ratio
of reducing agent. An attempt is made to explain the growth and correlate
the structural, optical and electrical properties.
Acute diarrhoea remains a major public health challenge in developing countries. We examined the role of a probiotic in the prevention of acute diarrhoea to discover if there was an effect directed towards a specific aetiology. A double-blind, randomized, controlled field trial involving 3758 children aged 1–5 years was conducted in an urban slum community in Kolkata, India. Participants were given either a probiotic drink containing Lactobacillus casei strain Shirota or a nutrient drink daily for 12 weeks. They were followed up for another 12 weeks. The primary outcome of this study was the occurrence of first episodes of diarrhoea. We assessed this during 12 weeks of intake of study agent and also for 12 weeks of follow-up. There were 608 subjects with diarrhoea in the probiotic group and 674 subjects in the nutrient group during the study period of 24 weeks. The level of protective efficacy for the probiotic was 14% (95% confidence interval 4–23, P<0·01 in adjusted model). The reduced occurrence of acute diarrhoea in the probiotic group compared to nutrient group was not associated with any specific aetiology. No adverse event was observed in children of either probiotic or nutrient groups. The study suggests that daily intake of a probiotic drink can play a role in prevention of acute diarrhoea in young children in a community setting of a developing country.
Faecal specimens of diarrhoea cases (n=2495, collected between November 2007 and October 2009) from Infectious Diseases and Beliaghata General (ID&BG) Hospital, Kolkata, India, were screened by RT–PCR using specific primers targeting region C of the capsid gene of noroviruses (NoVs) to determine the seasonal distribution and clinical characteristics of NoVs associated with diarrhoea. NoV infection was detected in 78 cases, mostly in children aged <2 years. In 22/78 positive cases, the virus was detected as the sole agent; others were as mixed infections with other enteric pathogens. Sequencing of NVGII strains showed clustering with GII.4 NoVs followed by GII.13 and GII.6 NoVs. Clinical characteristics of the diarrhoeic children and adults in Kolkata indicated that NoV infections were detected throughout the year and were associated with a mild degree of dehydration.
The distribution and virulence of Vibrio cholerae serogroups other than O1 and O139 in India before, during and after the advent of O139 serogroup was investigated. A total of 68 strains belonging to 31 different ‘O’ serogroups were identified during the study period. With the exception of O53, there was no spatial or temporal clustering of any particular non-O1 non-O139 serogroup at any given place. Two of the 68 strains examined produced cholera toxin (CT) which could only be partially absorbed with anti-CT immunoglobulin G. Tissue culture assay revealed that some of the non-O1 non-O139 strains produced factors which evoked either a cell rounding or cell elongation response depending upon the medium used. This study indicates that serogroups other than O1 and O139 should also be continuously monitored.
The study was carried out in symptomatic and asymptomatic women attending peripheral health centres to determine the laboratory prevalence of sexually transmitted infection (STI), reproductive tract infection (RTI) and HIV. A total of 4090 women in four study groups were subjected to general and speculum examination and screened for aetiological agents of RTI/STI by standard laboratory techniques. The main complaint was vaginal discharge, singly (11·2%) or along with other symptoms (49·0%). Prevalence of RTI/STI/HIV infection was 36·8%. Agents of RTIs were harboured by 24·3% and that of STIs by 12·5%. HIV seroprevalence was very low (0·1%). HSV-2 represented the commonest aetiological agent of STIs, suggesting the necessity of including anti-HSV treatment in the national syndromic management guidelines. The present study highlights the importance of routine RTI/STI screening of antenatal mothers to avoid adverse consequences to the unborn child, and periodic surveys to detect the infection pattern in symptomatic and asymptomatic women, in order to control HIV infection.
The dielectric response of La- and Dy- doped BiFeO3 thin films at microwave frequencies (up to 12 GHz) has been monitored as a function of frequency, direct current (dc) electric field, and magnetic field in a temperature range from 25 to 300 °C. Both the real and imaginary parts of the response have been found to be non-monotonic (oscillating) functions of measuring frequency. These oscillations are not particularly sensitive to a dc electric field; however, they are substantially dampened by a magnetic field. The same effect has been observed when the volume of the characterized sample is increased. This phenomenon is attributed to the presence of a limited number of structural features with a resonance type response. The exact origin of these features is unknown at present. Leakage current investigations were performed on the whole set of films. The films were highly resistive with low leakage current, thereby giving us confidence in the microwave measurements. These typically revealed ‘N’-type I-V characteristics.
In this study, we have analysed the epidemiological significance of the concurrent infections caused by Vibrio cholerae and intestinal parasites among different age groups of hospitalized diarrhoeal patients in Kolkata. A total of 3556 stool samples collected during 1996–2004 were screened for vibrios and parasites. The seasonality of V. cholerae and parasitic infections were studied in detail. The detection rates for Ascaris lumbricoides and Giardia lamblia infection were more than for the hookworm, Trichuris trichiura and Entamoeba histolytica. V. cholerae O1 was identified as the predominant serogroup among diarrhoeal patients. The highest rates for V. cholerae infection were in the 2–5 years age group and combined infection of V. cholerae and parasites was recorded among children aged between 2 and 10 years.
The dielectric response of La- and Dy- doped BiFeO3 thin films to electric- and magnetic fields was measured at microwave frequencies (up to 12GHz) in a temperature range from 25 °C to 300 °C. Interesting phenomena were observed. Significant oscillations in the C(f) characteristic which were unaffected by the electric field or by elevated temperature but which were dampened by a magnetic field. We also observed ‘N’-type I-V characteristics. A possible explanation for this mesoscopic response is the presence of structural features that cause resonance (e.g. grains, grain-boundaries, domains, domain walls etc), with a contribution strong enough to be averaged by the system. The exact origin of these features is unknown at present.
Primary open angle glaucoma (POAG) is a leading cause of late onset,
progressive, irreversible blindness and, although its etiology is poorly
understood, elevated intraocular pressure (IOP) often appears to be a
contributory factor. Proteomic and Western analyses of trabecular meshwork
(TM) from patients with POAG and age-matched controls originally
implicated cochlin as possibly contributing to glaucoma pathogenesis.
Cochlin deposits were subsequently detected in glaucomatous but not in
control TM and older glaucomatous TM was found to contain higher levels of
cochlin and significantly lower amounts of collagen type II. More
recently, similar results were reported in DBA/2J mice, which at older
ages develop elevated IOP, retinal ganglion cell degeneration, and optic
nerve damage. Notably, cochlin was absent in TM from C57BL/6J, CD1,
and BALBc/ByJ mice, which do not exhibit elevated IOP or glaucoma.
Cochlin was found in the TM of very young DBA/2J mice, prior to
elevated IOP, suggesting that over time the protein may contribute to the
events leading to increased IOP and optic nerve damage. Here we review
these findings and describe how future studies in DBA/2J mice can help
resolve whether cochlin plays a causal role in mechanisms of POAG and