985 research outputs found
Gateway-like absurdly-benign traversable wormhole solutions
A class of wormhole solutions is constructed that has restricted polar
degrees of freedom to achieve a gateway-like configuration. This compels the
use of distribution-valued metrics and connections which further compels the
use of neutrix product of distributions, to define distribution-valued
curvature, Einstein tensor, and other relevant quantities. The solution demands
a spacetime with non-Riemannian effects like non-metricity to be consistent and
well-defined, due to the non-associativity of the neutrix product. Finally, the
ideal gateway configuration where the negative energy requirement is zero is
derived.Comment: 24 pages, Accepted for print in the 'Theoretical and Mathematical
Physics' (Russian Academy of Sciences
4D Flat-space scattering amplitude / correlator correspondence revisited
In this paper, we make connection between CFT three point correlation
function of conserved currents and 4D three point amplitude of general spin
massless gauge field explicit. We do so by taking flat space limit of momentum
space CFT correlation function and show how they reproduce flat space
amplitudes. We then point out a mismatch between number of independent
structures in 3D CFT correlator of conserved currents and 4D flat space
covariant vertex of massless higher spin fields. This is in contrast with
general expectation that counting of 3d CFT correlator and 4d flat space
amplitude should match. This mismatch is even more pronounced in spinor
helicity variables. We also point out an interesting relation between parity
even and parity odd flat space amplitude in momentum space. This observation
helps us to construct a new momentum space CFT strtucture which accounts for
the mismatch. However we should mention that this extra CFT structure can't be
constructed out of conserved currents and hence counting mismatch between CFT
correlation of conserved currents and flat space amplitude of massless gauge
field persists. Story in spinor helicity variable is more complicated and is
discussed in detail. We further comment on the connection of CFT correlation
function in spinor helicity variables to AdS amplitudes in spinor helicity
variables and light cone variables.Comment: 28 pages + 17 pages appendix, some typographical errors fixed and
some more references added. Final results and conclusions unchange
Detection and characterization of metallo-β-lactamases producing Pseudomonas aeruginosa clinical isolates at a tertiary care hospital of Bhopal, India
Background: Carbapenems are very often used effectively against multidrug resistant strains of clinically troublesome pathogens like P. aeruginosa. But there is emerging threat of developing resistance against carbapenems mainly attributed to metallo-β-lactamases production which has proved to be a clinical disaster. Early detection and identification of MBL-producing strains is of crucial importance for the prevention of nosocomial dissemination through appropriate treatment, as well as the timely implementation of infection control measures. Therefore this study was undertaken for screening MBL production in clinical isolates of Pseudomonas aeruginosa.Methods: One hundred fifty consecutive clinical isolates of P. aeruginosa were subjected to susceptibility testing by disc-diffusion test as per CLSI 2014 guidelines. Imipenem resistant strains were then subjected to screening for MBL production by Imipenem- EDTA combined disc test and Imipenem-EDTA double-disc synergy test.Results: A total of 20 (13.3%) isolates of P. aeruginosa showed resistance to Imipenem out of which twelve (8%) were screened as MBL producers by CDT whereas 8 (5.3%) isolates gave positive result by DDST.Conclusions: Introduction of simple, cheap, reliable, reproducible screening tests for early detection and identification of MBL-producing organisms in routine diagnostics is of crucial importance for the prevention of nosocomial dissemination of MBL through appropriate treatment, as well as the timely implementation of effective infection control measures. Antibiotic Stewardship and strict antibiotic policy enforcing judicious use of antibiotics is the need of hour
Bacteriological profile of urinary tract infections at a tertiary care hospital in Western Uttar Pradesh, India
Background: This prospective study was intended to identify the bacterial pathogens causing urinary tract infections and their antimicrobial resistance patterns in a tertiary care teaching hospital of Western Uttar Pradesh, India.Methods: Clean-catch mid-stream urine samples were collected from patients symptomatic for UTI. Samples were cultured aerobically on CLED agar and strains having significant growth (>105cfu/ml) were further processed for identification using standard microbiological techniques and their antimicrobial susceptibility pattern evaluated by Kirby Bauer disk diffusion as per CLSI guidelines.Results: Out of the 2250 urine samples processed, 750 showed significant growth on aerobic culture. Thus, the prevalence of UTI in the population was 33.3%. E. coli was the commonest isolate (33.3%) followed by S. aureus (20 %), Klebsiella spp. (13.3%), Coagulase Negative Staphylococci (13.3%), Enterococcus spp. (6.7%), Pseudomonas spp. (6.7%) and Candida spp. (6.7%). Amongst these isolates, Gram negative bacilli have shown a high susceptibility to imipenem, levofloxacin, nitrofurantoin, linezolid and amoxyclav and Gram positive organisms towards levofloxacin, nitrofurantoin, linezolid, vancomycin and amikacin.Conclusions: This study has shown nitrofurantoin and fluoroquinolones to be the most effective drugs for the empirical therapy of UTI in our region. The study of antimicrobial susceptibility pattern of UTI in a particular area can guide the clinicians in the rational choice of antibiotic treatment so that misuse of antibiotics can be prevented
CHARACTERIZATION AND ANTIMICROBIAL SUSCEPTIBILITY PROFILE OF NON LACTOSE FERMENTING GRAM-NEGATIVE BACTERIAL ISOLATES IN A TERTIARY CARE TEACHING HOSPITAL OF CENTRAL INDIA
Objectives: The non-lactose fermenting Gram-negative bacilli (NLF-GNB) are notorious pathogens reportedly acquiring multiple drug resistance alarmingly and emerging as a public health threat globally. This study was conducted to isolate and identify these pathogens from clinical samples received routinely in our Bacteriology Laboratory and to analyze their antibiotic susceptibility patterns.
Methods: In this cross-sectional study, the first 100 NLF-GNB strains isolated consecutively from 1218 clinical samples were included through convenience sampling. The samples were processed using standard microbiological techniques.
Results: The most common isolate was Pseudomonas aeruginosa followed by Acinetobacter spp, Proteus spp, Shigella spp, Salmonella typhi, Providencia spp., and Morganella spp. P. aeruginosa and Acinetobacter spp. isolates were found to exhibit high susceptibility toward Colistin and Imipenem. Proteus spp. exhibited high sensitivity toward Imipenem, Aminoglycosides, Ceftazidime, and Cefepime. All Providencia isolates were susceptible to Amikacin, Cefepime, and Ceftriaxone. The only isolate of Morganella spp. was found to be susceptible to Amikacin, Cefepime, Ceftazidime, Piperacillin tazobactam, Ciprofloxacin, Imipenem, and Aztreonam. Shigella isolates exhibited very high susceptibility toward Imipenem followed by Gentamicin and Ceftazidime. All the isolates of S. typhi exhibited susceptibility toward Imipenem, Piperacillin tazobactam, Ceftazidime, Ceftriaxone, Cefoperazone sulbactam, and Chloramphenicol. 24% of test isolates were found to be Multidrug resistant.
Conclusion: Antimicrobial surveillance is needed to implement appropriate timely interventions to restrict the spread of multidrug-resistant clones. Strict infection prevention and control practices, with judicious antibiotic prescription policy, may help in tackling this problem by obviating the selection pressure
IN VITRO ANTIBACTERIAL ACTIVITY OF GREEN TEA EXTRACT AGAINST MULTIDRUG-RESISTANT BACTERIA
Objectives: This study aimed to evaluate the antimicrobial activity of ethanolic extract of green tea (Camellia sinensis) against multidrug-resistant strains of the pathogenic bacteria: Extended-spectrum-β-lactamase (ESBL) producing Enterobacteriaceae, Carbapenem-resistant Enterobacteriaceae (CRE), and Metallo-β-lactamase (MBL) producing Pseudomonas aeruginosa strains.
Methods: In this cross-sectional study, the antibacterial activity of ethanolic extract of commercial green tea against the 23 multidrug-resistant test strains was evaluated by the Agar well diffusion method, and the minimum inhibitory concentration of the extract for the test strains was determined by Agar plate dilution method.
Results: Ethanolic extract of green tea was found to exhibit a remarkably significant antimicrobial activity against the ATCC (American type culture collection) control strains: E. coli ATCC 25922 and P. aeruginosa ATCC 27853 with slightly higher activity against later as compared to the former. The extract exhibited a significant antibacterial activity against multidrug-resistant bacterial strains. The highest activity was shown against ESBL producing strains, followed by CRE strains and the least activity against MBL producers.
Conclusion: This study strongly depicts that the ethanolic extract of green tea exhibits significant antibacterial activity even against multidrug-resistant strains. Hence, such plant extracts could be a potential source of bioactive lead compounds that could be utilized in developing herbal antimicrobials as an alternative strategy for tackling the problem of antimicrobial resistance
Study of substitute frame method of analysis for lateral loading conditions
Analysis of multi-storey building frames involves lot of complications and tedious calculations by conventional methods. To carry out such analysis is a time consuming task. Substitute frame method for analysis can be handy in approximate and quick analysis so as to get the estimates ready and participate in the bidding process. Till date, this method has been applied only for vertical loading conditions. In this work, the applicability and effectiveness of this method has been checked under lateral loading conditions
Risk factors associated with periodontal diseases and their clinical considerations
Periodontal diseases are a group of chronic infections caused by pathogenic bacteria colonizing the periodontium. Initiation and progression of periodontal infections are affected by local and systemic conditions. The local factors include dental plaque and plaque retentive areas such as dental calculus and defective restorations. Systemic risk factors include poorly controlled diabetes mellitus and tobacco smoking. Systemic conditions associated with immunodefi ciency state such as neutropenia, AIDS/HIV infections are also important risk factors. Recent studies have revealed several potentially important periodontal risk indicators. These include stress and coping behaviors and osteopenia associated with estrogen deficiency. There are also demographic factors associated with periodontal disease including gender, and hereditary factors
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