Browsing by Author "P. Prakash"

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B-site disorder driven multiple-magnetic phases: Griffiths phase, re-entrant cluster glass, and exchange bias in Pr2CoFeO6
(American Institute of Physics Inc., 2019) Arkadeb Pal; Prajyoti Singh; V.K. Gangwar; Surajit Ghosh; P. Prakash; S.K. Saha; Amitabh Das; Manoranjan Kumar; A.K. Ghosh; Sandip Chatterjee
The magnetic spin ordering and the magnetization dynamics of a double perovskite Pr2CoFeO6 have been investigated by employing the (dc and ac) magnetization and neutron powder diffraction techniques. The study revealed that Pr2CoFeO6 adopted a B-site disordered orthorhombic structure (Pnma). Furthermore, ab initio band structure calculations suggested an insulating antiferromagnetic ground state. Magnetization measurements revealed that the system possesses a spectrum of competing magnetic phases, viz., long range canted antiferromagnetic (AFM) spin ordering (TN ∼269 K), Griffiths-like phase, re-entrant cluster glass (TG ∼34 K), and exchange bias effects. The neutron diffraction study divulged the exhibition of a long range G-type of canted AFM spin ordering. The random nonmagnetic dilution of magnetic Fe3+ (high spin) ions by Co3+ (low spin) ions due to B-site disorder essentially played a crucial role in manifesting such magnetic properties of the system. © 2019 Author(s).
Fasciolopsiasis: Endemic focus of a neglected parasitic disease in Bihar
(Wolters Kluwer Medknow Publications, 2015) A. Achra; P. Prakash; R. Shankar
Purpose: To describe a newly discovered, previously unreported endemic focus of fasciolopsiasis in the Phulwaria village, under tehsil Sugauli, East Champaran, Bihar. Materials and Methods: A study was conducted at village Phulwaria, following diagnosis of fasciolopsiasis in three children from the village. A total of 120 individuals, including all the children and adults who gave history of recent passage of red fleshy masses in their stool, were included in the study. The cases of fasciolopsiasis were treated with Praziquantel 25 mg/kg, three doses a day. Risk factors for the transmission of the parasite in the village were also studied. Results: Questionnaire revealed majority of the population suffering from abdominal discomfort and passage of red fleshy masses in stool. These fleshy masses were identified as Fasciolopsis buski. One hundred and eighteen individuals were presumably considered as cases of the parasitic infection. After treatment with Praziquantel, all of them passed the parasite in their stool for the next 2-3 days. On investigating, it was observed that all the conditions required for effective continuation of the life cycle of the parasite were present in this village. Conclusion: This study draws attention to a new endemic focus of fasciolopsiasis in Bihar, with a very high prevalence due to poverty, the lack of awareness about the parasite in villagers as well as ignorance among local medical practitioners. There is an urgent need for mass campaign around the region for its effective control. © 2015, Medknow Publications. All rights reserved.
Fungal keratitis in north India; Spectrum and diagnosis by Calcofluor white stain
(Wolters Kluwer Medknow Publications, 2015) M. Gupta; A. Chandra; P. Prakash; T. Banerjee; O.P.S. Maurya; R. Tilak
[No abstract available]
Increased prevalence of extended spectrum β lactamase producers in neonatal septicaemic cases at a tertiary referral hospital
(Medknow Publications and Media Pvt. Ltd, 2008) A. Bhattacharjee; M. Sen; P. Prakash; A. Gaur; S. Anupurba
Emergence of extended spectrum β lactamases (ESBLs) producing strains of gram negative bacteria, as one of the leading cause of septicaemia often complicates the clinical and therapeutic outcome. The present study was undertaken to investigate the prevalence of ESBLs in bacteria isolated from neonatal septicaemic cases along with their antimicrobial sensitivity pattern. Blood samples were collected from 243 suspected cases of neonatal septicaemia. Apart from susceptibility testing, all the gram negative isolates were subjected to phenotypic tests for ESBL production. Amongst the positive test samples (n = 115), 84 were gram negative rods. ESBL was detected in 26 (32%) isolates. Results indicate that routine ESBL detection should be made imperative and empirical use of third generation cephalosporins must be discouraged.
Investigation of multi-mode spin-phonon coupling and local B-site disorder in Pr2CoFeO6 by Raman spectroscopy and correlation with its electronic structure by XPS and XAS studies
(Institute of Physics Publishing, 2019) Arkadeb Pal; Surajit Ghosh; Amish G. Joshi; Shiv Kumar; Swapnil Patil; Prince K. Gupta; Prajyoti Singh; V.K. Gangwar; P. Prakash; Ranjan K. Singh; Eike F. Schwier; M. Sawada; K. Shimada; A.K. Ghosh; Amitabh Das; Sandip Chatterjee
Electronic structure of Pr2CoFeO6 (at 300 K) was investigated by x-ray photoemission spectroscopy (XPS) and x-ray absorption spectroscopy techniques. All three cations, i.e. Pr, Co and Fe were found to be trivalent in nature. XPS valance band analysis suggested the system to be insulating in nature. The analysis suggested that Co3+ ions exist in low spin state in the system. Moreover, Raman spectroscopy study indicated the random distribution of the B-site ions (Co/Fe) triggered by same charge states. In temperature-dependent Raman study, the relative heights of the two observed phonon modes exhibited anomalous behaviour near magnetic transition temperature TN ∼ 270 K, thus indicating towards interplay between spin and phonon degrees of freedom in the system. Furthermore, clear anomalous softening was observed below TN which confirmed the existence of strong spin-phonon coupling occurring for at least two phonon modes of the system. The line width analysis of the phonon modes essentially ruled out the role of magnetostriction effect in the observed phonon anomaly. The investigation of the lattice parameter variation across TN (obtained from the temperaturedependent neutron diffraction measurements) further confirmed the existence of the spin- phonon coupling. © 2019 IOP Publishing Ltd Printed in the UK.
Necessity to identify the causative agent for appropriate treatment in fungal corneal ulcer: an in vitro study
(Elsevier Masson SAS, 2018) M.K. Gupta; A. Chandra; P. Prakash; R. Tilak
Objective: Fungal corneal ulcers are a major cause of preventable blindness. Different antifungal agents as natamycin, nystatin, fluconazole, itraconazole, voriconazole are used to treat these ulcers. Among these, natamycin is most widely used as a treatment modality. In natamycin non-responding cases, other drugs especially voriconazole is used. This study was done to assess the use of antifungal drugs in the treatment of fungal corneal ulcer by determining the minimum inhibitory concentration against common fungal pathogens. Material and methods: Minimum inhibitory concentration of fluconazole, itraconazole, voriconazole, nystatin and natamycin was assessed against the 61 isolated corneal fungal pathogens as per CLSI guidelines. Results: MIC value of different antifungal agents varies as per fungal strains. Voriconazole showed the lowest MIC against the isolated fungi, in comparison to fluconazole and itraconazole. In comparison to other fungi, higher natamycin MIC was observed against Aspergillus species. Itraconazole is poorly effective against Fusarium sp. Conclusion: Identification of causative fungi is necessary before antifungal treatment. Lowest voriconazole MIC promotes its use as 1st line drug. Comparative higher natamycin MIC, especially against Aspergillus species, warns clinician to have MIC in each case of a non-responding fungal corneal ulcer. © 2017
Observation on integron carriage among clinical isolates of Klebsiella pneumoniae producing extended-spectrum β-lactamases
(Medknow Publications and Media Pvt. Ltd, 2010) A. Bhattacharjee; M.R. Sen; P. Prakash; A. Gaur; S. Anupurba; G. Nath
Purpose: Klebsiella pneumoniae is considered an important pathogen causing nosocomial and community-acquired infections and is often associated with the production of extended-spectrum -lactamases (ESBL) belonging to SHV and CTX-M families, which are frequently described as a part of complex integrons, facilitate their horizontal transfer to other related as well as unrelated microbes. The present study was undertaken to investigate the occurrence and characterization of integrons among K pneumoniae isolates producing ESBL in a tertiary referral hospital. Materials and Methods: A total of 136 clinical isolates of K pneumoniae were investigated for the presence of ESBL. Their ESBL genes were characterized by multiplex polymerase chain reaction (PCR). Integrase gene PCR was performed to detect the presence of integron. The isolates were further typed by random amplification of polymorphic DNA (RAPD). Result: Out of 136 K pneumoniae isolates, 63 (46%) were confirmed to be ESBL producers. SHV (68%) and CTX-M (67%) ESBL genes were the most common in our study. Of the 63 ESBL-positive isolates, 58 (92%) strains carried integrons; 52 strains (82%) carried only class 1 integron, whereas 6 (9%) isolates harboured both class 2 integrons and the class 1 gene. However, in ESBL negatives, only 29 (40%) strains were positive for class 1 integron and none for class 2 integron. Conclusion: The presence of class 2 integron amongst ESBL-producing K pneumoniae is being described for the first time in this part of the world. The findings of this study strongly suggest that integrons have a role in the dissemination of ESBL-mediated resistance among the nosocomial isolates of K pneumonia.
Observations on carbapenem resistance by minimum inhibitory concentration in nosocomial isolates of acinetobacter species: An experience at a tertiary care hospital in north India
(2008) A. Gaur; A. Garg; P. Prakash; S. Anupurba; T.M. Mohapatra
Acinetobacter species are emerging as an important nosocomial pathogen. Multidrug-resistant Acinetobacter spp. has limited the option for effective treatment. Although carbapenems are effective for the treatment of such infections, resistance to this drug has recently been reported. This study was undertaken to assess resistance to carbapenem in clinical isolates of Acinetobacter spp. from hospitalized patients by both disc-diffusion and minimum inhibitory concentration (MIC) methods. All clinical samples from suspected cases of nosocomial infections were processed, and 265 isolates were identified as Acinetobacter species. These isolates were tested for antibiotic resistance by the disc-diffusion method with 14 antimicrobials, including meropenem and imipenem. Thereafter, all Acinetobacter species were subjected to MIC for meropenem. More than 80% resistance to second- and third-generation cephalosporins, aminoglycosides, and quinolones was recorded. Thirty percent of the strains were resistant to cefoperazone/sulbactam. Resistance to meropenem was observed in 6.4% of Acinetobacter spp. while 8.3% of the isolates showed intermediate resistance detected by MIC. All carbapenem-resistant/intermediate strains were also resistant to other (>10) antibiotics tested by the disc-diffusion method. The rising trend of resistance to carbapenem poses an alarming threat to the treatment for such infections. Regular monitoring, judicious prescription, and early detection of resistance to carbapenem are necessary to check further dissemination of drug resistance in Acinetobacter spp. © International Centre for Diarrhoeal Disease Research, Bangladesh.
Role of pollen starch and soluble sugar content on fruit set in tomato under heat stress
(Society for the Advancement of Breeding Researches in Asia and Oceania, 2015) S. Kumar; P. Prakash; S. Kumar; K. Srivastava
The effects of heat stress on pollen starch and soluble sugar content in relation to fruit set were examined in 4 tomato genotypes under controlled condition at 2 temperature regimes, including optimal and high temperature. The optimal temperature conditions (OT, 28/21 °C) resulted in starch accumulation in the pollen grains, where it reached a maximum value before anthesis and diminished towards anthesis. Total soluble sugar concentration gradually increased in the pollen grains reaching a maximum at anthesis. Continuous exposure of the plants to high temperatures (HT, 37/27 °C) prevented the transient increase in starch concentration and led to decrease in the concentrations of soluble sugars in the pollen grains at anthesis. It also markedly reduced the percent pollen viability, pollen germination, and fruit set, as compared to optimal temperature (OT, 28/21°C). These results suggest that a major effect of heat stress on pollen development is a decrease in starch concentration before anthesis, which results in a decreased soluble sugar concentration in the mature pollen grains at anthesis. These events possibly contribute to the decreased pollen viability, pollen germination, and ability to fruit set in tomato. The results strongly indicated that 2 tomato genotypes (Pusa Sadabahar and NDTVR-60) could be a valuable source of heat-tolerant germplasm for tomato breeding programs. © Society for the Advancement of Breeding Research in Asia and Oceania (SABRAO) 2015.
Scytalidium infection associated with dyskeratosis congenita [17]
(2007) J. Garg; R. Tilak; A.K. Gulati; S. Singh; P. Prakash; A. Garg
[No abstract available]
Zinc Sulphate and Vermicompost Mitigate Phytotoxic Effects of Arsenic by Altering Arsenic Uptake, Biochemical and Antioxidant Enzyme Activities in Wheat (Triticum aestivum L.)
(Pleiades journals, 2021) S. Karmakar; P. Prakash; A. Chattopadhyay; D. Dutta
Abstract: Seedlings of wheat genotype HUW-234 (Triticum aestivum L.) were raised in pot soil culture using eight different treatment combinations, enriched with inorganic arsenic (AsV at 0, 30 mg/kg soil), zinc sulphate (Zn at 0, 20 mg/kg soil) and vermicompost (at 0, 15 t/ha). Plants exposed to As toxicity were found significantly (P ≤ 0.05) lower in total chlorophyll, carotenoids and soluble protein content and higher in proline accumulation. A significant (P ≤ 0.05) reduction in nitrate reductase (NR) activity was also noticed under this As stress. As toxicity severely altered the activities of several antioxidant scavenging enzymes in the test seedlings. Superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities were found elevated, whereas, catalase (CAT) showed a decrease in its activity in seedlings exposed to As stress. As a consequence, a significant (P ≤ 0.05) reduction in grain yield (up to 42%) was also recorded. Mitigation of toxic effects of As with significant (P ≤ 0.05) alteration in the biochemical constituents, as well as antioxidant enzymatic activities, was observed when supplemented with zinc sulphate and vermicompost whether alone or in combination. All these examined parameters were correlated either positively or negatively with the concentrations of As in wheat grain, straw and root. The rate of translocation of As in plants was increased when solely treated with As; while a decreasing trend was noticed for those plants which received zinc sulphate and vermicompost as treatment. Hence, this study faithfully establishes the relationship of zinc sulphate and vermicompost application with reduced As content in the plant part, thus resulting in better crop growth and yield. © 2021, Pleiades Publishing, Ltd.