Search

Balaji Veeraraghavan,1 Dhanasekhar Kesavelu,2 Bijesh Yadav1 1Christian Medical College, Vellore, Tamil Nadu, 632004, India; 2SS Child Care, Mogappair, West Chennai, 600037, IndiaCorrespondence: Balaji Veeraraghavan, Christian Medical College, Vellore, Tamil Nadu, 632004, India, Tel +919442210555, Email vbalaji@cmcvellore.ac.inAbstract: Gut microbiota starts colonizing from birth and reach the adult gut microbial profile by around three years of age. There are scarce data on the gut microbial profiles of Indian infants. Moreover, there are insufficient data comparing the types of gut microbiota in Indian and Western infants, at different stages of their growth between 0 and 24 months. Also, with increasing globalization, infants of one country of origin are born in another country or travel to another country during infancy. Hence, these infants are exposed to changing environment and food practices that often causes dysbiosis or imbalance in the healthy gut microbiota profile. Dysbiosis has been linked, directly or indirectly, with many neurodevelopmental, gastrointestinal, respiratory, and other health issues. Early probiotic supplementation is associated with the return to the gut microbiota profile to a healthy state at one year and beyond. The changing global scenarios warrant the availability of a probiotic that can be used across nations. However, this is possible only if the gut microbiota profile of Indian and Western infants is similar enough to encourage the use of same probiotic in both populations. Hence, a systematic literature search was carried out to assess if the microbiota profile of the Indian and Western infants was comparable. This systematic review included 29 studies (10 Indian and 19 Western) and found that despite some differences, the gut microbiota of Indian and Western infants aged 0– 24 months are largely similar, with implications for probiotic supplementation.Keywords: gut microbiota, Indian, Western, 0.24 months, infants

Bhuvan Yadav, Srujana Mohanty, Bijayini Behera Department of Microbiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha, 751019, IndiaCorrespondence: Srujana Mohanty, Department of Microbiology, All India Institute of Medical Sciences, Bhubaneswar, Odisha, 751019, India, Tel +9438884124, Email srujana_micro@yahoo.co.inPurpose: This study was conducted to find out the occurrence of hypervirulent Klebsiella pneumoniae (hvKP) isolates from different clinical specimens in a tertiary care hospital of eastern India and investigate the distribution of virulence factors, capsular serotypes and antibiogram profile. The distribution of carbapenemase-encoding genes in convergent (hvKP and carbapenem-resistant) isolates was also studied.Materials and methods: A total of 1004 K. pneumoniae isolates were obtained from different clinical specimens from August 2019 to June 2021 and hvKP isolates were identified using the string test. Genes of capsular serotypes K1, K2, K5, K20, K54 and K57, virulence-associated genes, rmpA, rmpA2, mrkD, allS, iroN, iutA, iuc, kfuB and ybtS, and carbapenemase-encoding genes, NDM-1, OXA-48, OXA-181, and KPC, were evaluated by polymerase chain reaction. Antimicrobial susceptibility was determined primarily by the VITEK-2 Compact automated platform (bioMérieux, Marcy-l’Étoile, France) and supplemented by disc-diffusion/EzyMIC (HiMedia, Mumbai, India) wherever needed.Results: Out of 1004 isolates, 33 (3.3%) were hvKP. Most frequent capsular serotype was K2 in 11 (33.3%). Amongst virulence genes, mrkD, iutA and kfuB were detected most frequently in 93.9%, 84.8% and 63.6% isolates respectively. Classical Klebsiella pneumoniae isolates were significantly more resistant than hvKP to cephalosporins, amoxicillin-clavulanic acid, and fluoroquinolones (p < 0.05). Carbapenem resistance was seen in 10 hvKP convergent isolates with the most prevalent carbapenemase-encoding gene being OXA-48 and OXA-181 in 50% isolates.Conclusion: There is a need for continued surveillance of hvKP strains in view of the impending threat of a global spread of convergent strains.Keywords: antimicrobial resistance, carbapenem-resistantK. pneumoniae, hypervirulent Klebsiella pneumoniae, Klebsiella pneumoniae, virulence gene

In the present study, we have investigated the effect of magnetic Cr doping on the transport properties of a sputtered Bi2Se3 thin film on the SrTiO3 (110) substrate. The high-resolution x-ray diffraction and Raman spectroscopy measurements revealed the growth of rhombohedral Bi2Se3 thin films. Further electronic and compositional analysis was done by x-ray photoemission spectroscopy and Rutherford backscattering spectroscopy, and the x-value was estimated to be 0.18 in the Bi2−xCrxSe3 thin film. The variation in the resistivity with temperature (2–300 K) revealed the metallic nature in undoped Bi2Se3 up to 30 K and upturn resistivity below 30 K. The Cr-doped Bi2Se3 resistivity data show a traditional semiconducting nature up to 25 K and take an abrupt upturn resistivity below 25 K. The resistivity behavior of both samples was explained by adopting a model that consists of the total resistance, a combination of bulk and surface resistance in parallel. The bulk bandgap value determined by this method is obtained to be 256 meV in an undoped Bi2Se3 thin film. Magnetoconductance data of the undoped thin film revealed a weak anti-localization (WAL) effect, while the Cr-doped thin film showed a weak localization (WL) effect at low temperatures (<50 K). At low magnetic field and low temperature, a competing nature of WAL and WL effects was prominent in the Cr-doped film. A drastic increase in the electrical resistance suggests that Cr doping can significantly modify the electrical properties of Bi2Se3 thin films, which could have potential applications in futuristic devices. [ABSTRACT FROM AUTHOR]

In the past few decades, perovskite materials have attracted the attention in research due to a wide range of applications in sensors and solid-state fuel cells. Perovskite lanthanum ferrite has also significant importance in LPG and humidity sensors for its photocatalytic activity and temperature-dependent surface morphology. The doping of CNT in perovskite ceramics plays a vital role in enhancing surface activity. CNT-doped Lanthanum ferrite sample was prepared by Sol–gel process. The well-prepared lanthanum ferrite samples were characterized for thermal, crystallographic, surface morphological, molecular, and optical studies. Differential scanning calorimetry study shows the clear crystallization of LaFeO3 after decomposition and removal of organic species. X-ray diffraction study also confirms the crystallization of cubic LaFeO3 with a minimum crystallite size of 38 nm. Scanning electron microscopic studies of lanthanum ferrite pellet and thick-film samples show the presence of large number of pores in uniformly distributed grains and particles. The pores in the thick-film sample were found to be higher in the pellet sample. XPS and EDS analysis confirm the elemental composition as La, Fe, O, and C. The optical band gap of the composite material was found to be 4.05 eV. The increase in band gap with LPG exposure on sensing element is also validated by DFT analysis. The maximum values of percentage sensor responses were found to be 431 and 480 at 5000-ppm LPG for pellet and film, respectively for LPG sensing. The thick film shows a better response in comparison to pellet over the entire range of gas sensing. The doping of 1 mol% CNT in lanthanum ferrite enhances the sensor response significantly. [ABSTRACT FROM AUTHOR]