18 research outputs found
Determining target species for assessment in multispecies and multigear fisheries: insights from an expanded CMFRI-NMFDC database
This paper highlights the richness of information available in an expanded ICAR-CMFRI-NMFDC fish catch and effort database for the state of Kerala. Strengthening of the database by digitizing data in the old paper data sheets was done under a multi-national project, ICAR-CMFRI-CSIRO-LENFEST Ocean Programme. The high diversity of fished taxa was classified according to the periodicity of its occurrence over this long period. Guidelines for determining the number of species for which stock assessment is to be carried out in the context of a multigear and multispecies fisheries sector were derived. This national-level database will be of immense use to researchers and policy makers for preparing fisheries management plans for the sustainable harvest of marine fishery resources
Status of Indian marine fish stocks: modelling stock biomass dynamics in multigear fisheries
A biomass dynamics modelling study to derive biological reference points and management requirements of 223 commercially important fish
stocks in different maritime states of India was conducted. Two decades (1997–2016) of fishery-related data on the harvest of resources by
different types of fishing fleets formed the input. The multigear nature of the fishery situation was solved by introducing a gear standardization parameter into the biomass dynamics model. The relative positions of the fish stocks were depicted through Kobe plots generated for
the ten maritime states/union territory, and the fish stocks were categorized, based on the status, into sustainable, overfished, recovering, and
overfishing. The results indicate that 34.1% of the assessed fish stocks in the country are sustainable, 36.3% are overfished, 26.5% are recovering, and 3.1% are in the overfishing status. Regionally, the percentage of sustainable fish stocks were high along the southwest coast (51.6%),
overfished stocks were high along the northwest coast (54.2%), and recovering fish stocks were high along the northeast coast (47.8%).
The national mean B/BMSY was estimated as 0.86, which is a strong reason for strengthening fisheries management. Fishing fleets harvesting
overfished stocks were examined for each maritime state, and recommendations regarding reduction in annual fishing hours are made
Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial
SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication
Characterization and Pathogenicity of Vibrio cholerae and Vibrio vulnificus from Marine environments
The genus Vibrioof the family Vibrionaceae are Gram negative, oxidasepositive,
rod- or curved- rodshaped facultative anaerobes, widespread in marine
and estuarine environments. Vibrio species are opportunistic human pathogens
responsible for diarrhoeal disease, gastroenteritis, septicaemia and wound
infections and are also pathogens of aquatic organisms, causing infections to
crustaceans, bivalves and fishes. In the present study, marine environmental
samples like seafood and water and sediment samples from aquafarms and
mangroves were screened for the presence of Vibrio species. Of the134 isolates
obtained from the various samples, 45 were segregated to the genus Vibrio on the
basis of phenotypic characterization.like Gram staining, oxidase test, MoF test and
salinity tolerance. Partial 16S rDNA sequence analysis was utilized for species
level identification of the isolates and the strains were identified as V.
cholerae(N=21), V. vulnificus(N=18), V. parahaemolyticus(N=3), V. alginolyticus
(N=2) and V. azureus (N=1). The genetic relatedness and variations among the 45
Vibrio isolates were elucidated based on 16S rDNA sequences. Phenotypic
characterization of the isolates was based on their response to 12 biochemical tests
namely Voges-Proskauers’s (VP test), arginine dihydrolase , tolerance to 3% NaCl
test, ONPG test that detects β-galactosidase activity, and tests for utilization of
citrate, ornithine, mannitol, arabinose, sucrose, glucose, salicin and cellobiose.
The isolates exhibited diverse biochemical patterns, some specific for the species
and others indicative of their environmental source.Antibiogram for the isolates
was determined subsequent to testing their susceptibility to 12 antibiotics by the
disc diffusion method. Varying degrees of resistance to gentamycin (2.22%),
ampicillin(62.22%), nalidixic acid (4.44%), vancomycin (86.66), cefixime
(17.77%), rifampicin (20%), tetracycline (42.22%) and chloramphenicol (2.22%)
was exhibited. All the isolates were susceptible to streptomycin, co-trimoxazole,
trimethoprim and azithromycin. Isolates from all the three marine environments
exhibited multiple antibiotic resistance, with high MAR index value.
The molecular typing methods such as ERIC PCR and BOX PCR revealed
intraspecies relatedness and genetic heterogeneity within the environmental
isolatesof V. cholerae and V. vulnificus. The 21 strains of V. choleraewere
serogroupedas non O1/ non O139 by screening for the presence O1rfb and O139
rfb marker genes by PCR.
The virulence/virulence associated genes namely ctxA, ctxB, ace, VPI,
hlyA, ompU, rtxA, toxR, zot, nagst, tcpA, nin and nanwere screened in V. cholerae
and V. vulnificusstrains.The V. vulnificusstrains were also screened for three
species specific genes viz., cps, vvhand viu. In V. cholerae strains, the virulence
associated genes like VPI, hlyA, rtxA, ompU and toxR were confirmed by PCR.
All the isolates, except for strain BTOS6, harbored at least one or a combination
of the tested genes and V. choleraestrain BTPR5 isolated from prawn hosted the
highest number of virulence associated genes. Among the V. vulnificusstrains,
only 3 virulence genes, VPI, toxR and cps, were confirmed out of the 16 tested
and only 7 of the isolates had these genes in one or more combinations. Strain
BTPS6 from aquafarm and strain BTVE4 from mangrove samples yielded positive
amplification for the three genes.
The toxRgene from 9 strains of V. choleraeand 3 strains of V. vulnificus
were cloned and sequenced for phylogenetic analysis based on nucleotide and the
amino acid sequences. Multiple sequence alignment of the nucleotide sequences
and amino acid sequences of the environmental strains of V. choleraerevealed that
the toxRgene in the environmental strains are 100% homologous to themselves
and to the V. choleraetoxR gene sequence available in the Genbank database. The
3 strains of V. vulnificus displayed high nucleotide and amino acid sequence
similarity among themselves and to the sequences of V. cholerae and V. harveyi
obtained from the GenBank database, but exhibited only 72% homology to the
sequences of its close relative V. vulnificus.
Structure prediction of the ToxR protein of Vibrio cholerae strain BTMA5
was by PHYRE2 software. The deduced amino acid sequence showed maximum
resemblance with the structure of DNA-binding domain of response regulator2
from Escherichia coli k-12 Template based homology modelling in PHYRE2
successfully modelled the predicted protein and its secondary structure based on
protein data bank (PDB) template c3zq7A.
The pathogenicity studies were performed using the nematode
Caenorhabditiselegansas a model system. The assessment of pathogenicity of
environmental strain of V. choleraewas conducted with E. coli strain OP50 as the
food source in control plates, environmental V. cholerae strain BTOS6, negative
for all tested virulence genes, to check for the suitability of Vibrio sp. as a food
source for the nematode;V. cholerae Co 366 ElTor, a clinical pathogenic strain
and V. cholerae strain BTPR5 from seafood (Prawn) and positive for the tested
virulence genes like VPI, hlyA, ompU,rtxA and toxR. It was found that V.
cholerae strain BTOS6 could serve as a food source in place of E. coli strain OP50
but behavioral aberrations like sluggish movement and lawn avoidance and
morphological abnormalities like pharyngeal and intestinal distensions and
bagging were exhibited by the worms fed on V. cholerae Co 366 ElTor strain and
environmental BTPR5 indicating their pathogenicity to the nematode.
Assessment of pathogenicity of the environmental strains of V. vulnificus
was performed with V. vulnificus strain BTPS6 which tested positive for 3
virulence genes, namely, cps, toxRand VPI, and V. vulnificus strain BTMM7 that
did not possess any of the tested virulence genes. A reduction was observed in the
life span of worms fed on environmental strain of V. vulnificusBTMM7 rather than
on the ordinary laboratory food source, E. coli OP50. Behavioral abnormalities
like sluggish movement, lawn avoidance and bagging were also observed in the
worms fed with strain BTPS6, but the pharynx and the intestine were intact.
The presence of multi drug resistant environmental Vibrio strainsthat
constitute a major reservoir of diverse virulence genes are to be dealt with caution
as they play a decisive role in pathogenicity and horizontal gene transfer in the
marine environments.Cochin University of Science & Technolog
Improvement in corrosion resistance of magnesium-aluminum alloy via friction stir processing
Friction stir processing was done for surface modification of cast Magnesium-Aluminum alloy. The microstructural characteristics related to different phases of untreated cast Magnesium-Aluminum alloy, friction stir processed under different process parameters like rotational speeds at 380rpm and 545 rpm with 31.5 mm/min transverse speed with and without pure aluminum powder were investigated by Metallurgical microscopy at lower magnification and scanning electron microscopy at higher magnification. Pure aluminum powder of fine size (~19μm) was filled in the groove made at the center of the Magnesium-Aluminum alloy plate which cover 33 vol% of pure aluminum during friction stir processing. The electrochemical behavior of the Magnesium-Aluminum alloy, Friction stir processed Magnesium-Aluminum alloy without aluminum powder and Friction stir processed Magnesium-Aluminum alloy with pure aluminum powder were investigated using Potentiostat in 5 wt % sodium chloride (NaCl) solution.Surface of all conditions specimens were analyzed for the phases present on the surface by X-Ray Diffractometer (XRD) which revealed different peaks of α-Mg phase, β-phases (Mg17Al12) and Pure Aluminum . In friction stir processed Magnesium-Aluminum alloy double pass with aluminum powder all these peaks were observed. The electrochemical corrosion tests revealed the least corrosion rate (0.603 X 102mpy) for friction stir processed double pass with aluminum powder amongst all the tested specimens. The improvement in corrosion resistance of friction stir processed double pass with aluminum powder is because of more formations of the β-phases (Mg17Al12) and aluminum dissolved in the α-Mg phase
Occurrence of potential pathogenic Aeromonas species in tropical seafood, aquafarms and mangroves off Cochin coast in South India
Exploring the photocatalytic potential of copper iodide thin films deposited via multiple spray technique
This study explores the optimization of deposition parameters for CuI thin films, and investigates their potential application as photocatalysts. γ-CuI thin films were grown on glass substrate using the nebulized spray method at different substrate temperatures. Structural, morphological, and optical studies of the films were carried out. The substrate temperature was found to have a profound influence in determining the aforesaid properties of the films. As seen from scanning electron micrographs, the morphology of the films varied from discontinuous to uniform, and then to being agglomerated, when substrate temperature was increased from 50 °C to 175 °C. At the same time, it was observed from x-ray diffraction studies that films with better crystallite size was formed at lower temperatures. To obtain films with good crystallinity as well as continuous morphology, multiple spraying was carried out which involve repeating the deposition process manifold on the same substrate. Systematic characterization showed that multiple spraying at low temperatures resulted in uniform films with good crystallinity. The photocatalytic activity of single, double and triple sprayed CuI thin films prepared by nebulized spray method under visible light irradiation was also investigated. All of the films exhibited photocatalytic activity in the visible spectral region, with the triple-sprayed CuI thin film exhibiting the greatest efficiency in the photocatalytic degradation of Methylene blue
Investigation on the High Vacuum Tribological Characteristics of Surface Treated Nuclear Grade Stainless Steel Type AISI 316 LN at 25 to 500 degrees C
Although some researchers have published friction and wear data of Plasma Nitride (PN) coatings, the tribological behavior of PN/PN Pairs in high vacuum environment has not been published so far In order to bridge this knowledge gap, tribological tests under dry conditions have been conducted on PN/PN Pairs for varying temperatures of 25, 200, 400 and 500 degrees C in high vacuum (1.6 x 10(-4) bar) environment. The PN coatings showed good wear resistance layer on the ring surface. The PN coatings were removed only from the pin surface for all the tests since it contacts at a point. The friction and wear were low at lower temperatures and it eliminated adhesion between the contact surfaces until the coating was completely removed from the pin surface. (C) 2011 Journal of Mechanical Engineering. All rights reserved