Rapid Colorimetric and Fluorometric Discrimination of Maleic Acid vs. Fumaric Acid and Detection of Maleic Acid in Food Additives

An anthracene thiazole based Schiff base L was synthesized and employed for fluorescence switch-on detection of maleic acid in aqueous DMSO. The non-fluorescent L (10-5 M) showed an instantaneous and selective fluorescence enhancement at 506 nm upon interaction with maleic acid (10-5 M). Other potential carboxylic acids (10-5 M), such as malic acid, citric acid, acetic acid, cinnamic acid, tartaric acid, succinic acid, fumaric acid, oxalic acid and malonic acid failed to alter the chromo-fluorogenic properties of L. Probe L can be employed to detect maleic acid down to 2.74 × 10-6 M. The probe L showed good linearity from 2.97 to 6.87 µM. Analytical utility of L was examined by detecting maleic acid in various food additives and drosophila larvae.

Protein interactions, molecular docking, antimicrobial and antifungal studies of terpyridine ligands

Resistance to antibiotics/antibacterials/antifungals in pathogenic microbes has been developing over the past few decades and has recently become a commonplace public-health peril. Thus, alternative nontoxic potent antibiotic agents are covertly needed to control antibiotic-resistant outbreaks. In an effort to combat the challenges posed by the co-occurrence of multidrug resistance, two terpyridine ligands 4'-(4-N,N'-dimethylaminophenyl)-2,2':6',2″-terpyridine (L1) and 4'-(4-tolyl)-2,2':6',2″-terpyridine (L2) have been designed, prepared and confirmed their structure by spectral studies. Thereafter, antimicrobial assay was performed against gram positive and negative bacterial strains along with fungal strains. Both compounds L1 and L2 exhibited remarkable inhibitory activities against bacteria, Escherichia coli and Staphylococcus aureus at MIC values 6.25 and 3.125 µg/ml, respectively. In addition, in silico molecular docking studies were ascertained with bacterial DNA gyrase and fungal demethylase. Furthermore, both L1 and L2 could bind Bovine Serum Albumin (BSA) protein and binding interaction has been studied with the help of UV-Visible and fluorescence spectroscopy. While fluorescence of BSA unperturbed in the presence of L2, an addition of L1 to the solution of BSA resulted significant quenching. The binding constant calculations at different temperature confirmed that the fluorescence quenching between BSA and L1 is predominantly static in nature. The toxicity of L1 and L2 was checked using Drosophila melanogaster. The toxicity analysis suggest both the dyes are non-cytotoxic in nature.Communicated by Ramaswamy H. Sarma.

Pyrene-based fluorescent chemosensor for rapid detection of water and its applications

This manuscript introduces a pyrene-based Schiff base L by reacting pyrenecarboxaldehyde with 2-aminothiazole in equimolar ratio. The ligand L was characterized by various spectral data and single crystal. The water sensing ability of L was examined in different organic solvents. The weakly emissive L in DMSO showed a fluorescence enhancement upon the addition of water. The water-induced fluorescence enhancement of L was occurred due to the combined effect of aggregation-induced emission (AIE) phenomenon and suppression of photo-induced electron transfer (PET) process. Using L, the water in DMSO can be detected down to 0.50 wt% with a quantification limit of 1.52 wt%. The analytical novelty of the developed sensor L was validated by detecting moisture in a variety of raw food products.

Trend in seroprevalence of SARS-CoV-2 (IgG antibody) among tribal-dominated population: Findings from Jharkhand, India

Background & objectives

Serosurvey of COVID-19 provides a better estimation of people who have developed antibodies against the infection. Undertaking such a serosurvey in certain districts of India which are densely populated with prominent tribes can provide valuable information regarding seropravelance of SARS-CoV-2 antibodies among such indigenous populations. In this context, two rounds of population-based, cross-sectional serosurveys for SARS-CoV-2 IgG antibody were carried out in Jharkhand, a tribal-dominated State of India, to compare the seroprevalence of SARS-CoV-2 infection and to determine the associated demographic risk factors.

Methods

The surveys were carried out in June 2020 and February 2021 in ten districts of the State of Jharkhand. Blood samples were collected from the residents of the selected districts by random sampling and tested for anti-SARS-CoV-2 antibodies using an automated chemiluminescence immunoassay platform. A total of 4761 and 3855 eligible participants were included in round 1 and round 2, respectively.

Results

The age- and gender-standardized seroprevalence for COVID-19 during round 1 was 0.54 per cent (0.36-0.80) that increased to 41.69 per cent (40.16-43.22) during round 2 with a gap of eight months in between. The seropositivity among male and female participants was 0.73 and 0.45 per cent, respectively, during the first round and 51.35 and 33.70 per cent, respectively, during the second round. During the first round, 17.37 per cent of the participants were tribal with seropositivity of 0.24 per cent (0.02-0.87), and during the second round, 21.14 per cent were tribal with seropositivity of 39.14 per cent (35.77-42.59). Compared to tribal group, non-tribal participants had an adjusted odds of 1.24 (95% confidence interval=1.04-1.48) for SARS-CoV-2 seropositivity.

Interpretation & conclusions

COVID-19 seroprevalence was found to be low during the first round (0.54%) of the survey, possibly due to the travel restrictions during lockdown better adherence to social distancing and wearing of face masks among the people. Understanding the dynamics of SARS-CoV-2 transmission and the susceptibility to infection at the individual as well as community level will inform decision and help policy makers to design and implement effective public health strategies to mitigate the pandemic in this State.

A qualitative exploratory study using One Health approach for developing an intervention package for elimination of human anthrax in an endemic district of Odisha, India

Background & objectives:

Anthrax is a zoonotic disease of public health concern in India. One of the key predisposing factors is linked to the behaviour of the community. This study was nested within a baseline survey to understand the risk perception, attitude, socio-cultural and behavioural practices among different communities in an anthrax endemic tribal district of Odisha, India. It was aimed to explore the systemic gaps from the officials of different departments while addressing the animal and human anthrax cases and the knowledge, attitude, and behavioural practices among the tribal communities with regards to both animal and human anthrax signs, symptoms, and transmission from animal to human.

Methods:

A qualitative exploratory study was carried out in the district of Koraput, Odisha. Insights from eight focus group discussions (FGDs) and 42 in-depth-interviews (IDIs) with the stakeholders from health, veterinary, forest, general administrative departments and community were collected and analyzed thematically.

Results:

Major themes that emerged were inter-departmental coordination, livestock vaccination, surveillance network, laboratory facilities, prevention and control strategies with regards to the animal and human anthrax cases. The study also emphasized setting up the surveillance system as per the standard guidelines, and strengthening the diagnostic facilities for timely detection of confirmed cases. It also highlighted the current needs and the gaps among inter-sectoral coordination, collaboration, and sensitization among Health, Veterinary, Forest, Education, Nutrition, and Tribal Welfare Departments at various levels to reduce the prevalence and control the outbreaks of anthrax in the district and State.

Interpretation & conclusions:

The coordination gaps, financial burden, insufficient relevant knowledge and information among the concerned stakeholders were the issues found in this study in addition to non-availability of proper diagnostic facility. The coordination among different departments adapting One Health approach may be one of the best possible ways for the elimination of anthrax cases in an endemic region.

Tate J, D. Parashar U, Kang G. Rotavirus Strain Distribution before and after Introducing Rotavirus Vaccine in India

In April 2016, an indigenous monovalent rotavirus vaccine (Rotavac) was introduced to the National Immunization Program in India. Hospital-based surveillance for acute gastroenteritis was conducted in five sentinel sites from 2012 to 2020 to monitor the vaccine impact on various genotypes and the reduction in rotavirus positivity at each site. Stool samples collected from children under 5 years of age hospitalized with diarrhea were tested for group A rotavirus using a commercial enzyme immunoassay, and rotavirus strains were characterized by RT-PCR. The proportion of diarrhea hospitalizations attributable to rotavirus at the five sites declined from a range of 56–29.4% in pre-vaccine years to 34–12% in post-vaccine years. G1P[8] was the predominant strain in the pre-vaccination period, and G3P[8] was the most common in the post-vaccination period. Circulating patterns varied throughout the study period, and increased proportions of mixed genotypes were detected in the post-vaccination phase. Continuous long-term surveillance is essential to understand the diversity and immuno-epidemiological effects of rotavirus vaccination.

Rotavirus Gastroenteritis Hospitalizations Among Under-Five Children in Bhubaneswar, Odisha, India

OBJECTIVE

To report rotavirus-associated AGE (AGE) profile of admitted children among vaccine-introduced areas in Bhubaneswar, Odisha.

METHODS

This study was conducted between 2016 and 2019 at the Capital Hospital, Jagannath hospital and Hi-Tech Medical College and Hospital. All AGE patients below five years old, hospitalized in the study facilities were enrolled. A stool sample was collected and transported to the central laboratory (Christian Medical College, Vellore) for rotavirus antigen detection and genotyping. Clinical and demographic information was collected using a predesigned case report format (CRF).

RESULTS

Out of the 1213 stool samples, 447 (36.9%) were identified to have rotavirus with 350 (78.3%) of them belonging to 6 mo to 2 y age group. Rotavirus gastroenteritis exhibited a single peak from November to February. A total of 414 (92.6%) of rotavirus gastroenteritis children had severe or very severe dehydration with odds of rotavirus diarrhea leading to severe dehydration being 1.5 (95% CI, 1-2.4) compared to moderate dehydration. The common genotype combination was G3P[8] (46%) followed by G1P[8] (19%), G2P[4] (5%), and G9P[4] (3%).

CONCLUSION

Rotavirus gastroenteritis peaked between December to February while the most common genotype combination among the rotavirus GE was G3P[8] and G1P[8]. The present study provides the clinical profile of admitted children in the hospitals with diarrhea and the circulating strains of rotavirus which will help in documenting the epidemiology and the performance of vaccine against the disease in the state.

Intussusception after Rotavirus Vaccine Introduction in India

BACKGROUND

A three-dose, oral rotavirus vaccine (Rotavac) was introduced in the universal immunization program in India in 2016. A prelicensure trial involving 6799 infants was not large enough to detect a small increased risk of intussusception. Postmarketing surveillance data would be useful in assessing whether the risk of intussusception would be similar to the risk seen with different rotavirus vaccines used in other countries.

METHODS

We conducted a multicenter, hospital-based, active surveillance study at 27 hospitals in India. Infants meeting the Brighton level 1 criteria of radiologic or surgical confirmation of intussusception were enrolled, and rotavirus vaccination was ascertained by means of vaccination records. The relative incidence (incidence during the risk window vs. all other times) of intussusception among infants 28 to 365 days of age within risk windows of 1 to 7 days, 8 to 21 days, and 1 to 21 days after vaccination was evaluated by means of a self-controlled case-series analysis. For a subgroup of patients, a matched case-control analysis was performed, with matching for age, sex, and location.

RESULTS

From April 2016 through June 2019, a total of 970 infants with intussusception were enrolled, and 589 infants who were 28 to 365 days of age were included in the self-controlled case-series analysis. The relative incidence of intussusception after the first dose was 0.83 (95% confidence interval [CI], 0.00 to 3.00) in the 1-to-7-day risk window and 0.35 (95% CI, 0.00 to 1.09) in the 8-to-21-day risk window. Similar results were observed after the second dose (relative incidence, 0.86 [95% CI, 0.20 to 2.15] and 1.23 [95% CI, 0.60 to 2.10] in the respective risk windows) and after the third dose (relative incidence, 1.65 [95% CI, 0.82 to 2.64] and 1.08 [95% CI, 0.69 to 1.73], respectively). No increase in intussusception risk was found in the case-control analysis.

CONCLUSIONS

The rotavirus vaccine produced in India that we evaluated was not associated with intussusception in Indian infants. (Funded by the Bill and Melinda Gates Foundation and others.).

Role of Ni substitution on structural, magnetic and electronic properties of epitaxial CoCr2O4 spinel thin films

Cubic spinel CoCr2O4 has recently attained attention due to its multiferroic properties. However, the Co site substitution effect on the structural and magnetic properties has rarely been studied in thin film form. In this work, the structural and magnetic properties of Co1-x Ni x Cr2O4 (x= 0, 0.5) epitaxial thin films deposited on MgAl2O4 (100) and MgO (100) substrates to manipulate the nature of strain in the films using pulsed laser deposition (PLD) technique are presented. The epitaxial nature of the films was manifested through x-ray diffraction (XRD), reciprocal space mapping (RSM) and Rutherford backscattering spectrometry (RBS) measurements. Raman measurements revealed a disappearance of characteristic A 1 g and F 2 g modes of the CoCr2O4 with increase in the Ni content. Atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM) studies show a modification of the surface morphology upon Ni substitution. Magnetic measurements disclose that the ferrimagnetic Curie temperature (T C) of the CoCr2O4 in thin film grown on MgAl2O4 (100) and MgO (100) substrates were found to be 100.6 ± 0.5 K and 93.8 ± 0.2 K, respectively. With Ni substitution the T C values were found to be enhanced to 104.5 ± 0.4 K for MgAl2O4 (100) and 108.5 ± 0.6 K for MgO (100) substrates. X-ray photoelectron spectroscopy (XPS) suggests Cr3+ oxidation states in the films, while Co ions are present in a mixed Co2+/Co3+ oxidation state. The substitution of Ni at Co site significantly modifies the line shape of the core level as well as the valence band. Ni ions are also found to be in a mixed 2+/3+ oxidation state. O 1s core level display asymmetry related to possible defects like oxygen vacancies in the films.

Anomalous luminescent properties in ZnO and SrAl2O4composites

We showed a phase transformation from high temperature hexagonal phase to most stable monoclinic phase of SrAl₂O₄by incorporating 20% of ZnO in ZnO and SrAl₂O₄composite (Singhet al.2014Dalton Transactions). The composite with monoclinic phase further showed the intense near band edge emission and defect band emission corresponding to ZnO without any signature of SrAl₂O₄in PL spectra. An energy band diagram responsible for defect band emission is proposed for the composites.

TiO2 nanowires grown from nanoparticles: structure and charge density study

We report the synthesis of TiO2 nanowires with high aspect ratio using a two step hydrothermal process using TiO2 nanoparticles and 10 M NaOH solvent at a reaction temperature of 180 degrees C. These nanowires are characterized by field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), micro-Raman and X-ray photo emission spectroscopy (XPS). Phase of the nanowires are found to be anatase, confirmed from both XRD and Raman spectroscopic measurements. High resolution electron microscopy (HREM) further supports the anatase structure and selected area electron diffraction (SAED) pattern indicate the single crystalline nature of the nanowires. Addition to these techniques, XPS and EDS refutes the presence of any impurity elements like Na as reported in the literatures. The electronic structures of the nanoparticles and nanowires are studied with maximum entropy method (MEM) using the XRD tools. Nanowires are found to be more ionic than the nanoparticles evidenced from the MEM simulations.