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1.
Diagn Microbiol Infect Dis ; 110(1): 116398, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38908041

ABSTRACT

Carbapenem-resistant significant members of Acinetobacter calcoaceticus-Acinetobacter baumannii (CR-SM-ACB) complex have emerged as an important cause of sepsis, especially in ICUs. This study demonstrates the application of loop-mediated-isothermal-amplification (LAMP) assay for detection of CR-SM-ACB-complex from patients with sepsis. Whole-blood and culture-broths(CB) collected from patients with culture-positive sepsis were subjected to LAMP and compared with PCR, and RealAmp. Vitek-2 system and conventional PCR results were used as confirmatory references. The sensitivity and specificity of LAMP(97 % & 100 %) and RealAmp(100 % & 100 %) for detection of CR-SM-ACB-complex from CB were better than PCR(87 % & 100 %). Diagnostic accuracy of LAMP, RealAmp, and PCR for detection of SM-ACB-complex from CB was 98.5 %, 100 %, and 88.5 % respectively. Turnaround time of Culture, LAMP, PCR, and RealAmp was 28-53, 6-20, 9-23, and 6-20hours, respectively. LAMP is a simple, inexpensive tool that can be applied directly to positive CB and may be customized to detect emerging pathogens and locally-prevalent resistance genes and to optimize antimicrobial use.

2.
Phys Rev Lett ; 132(12): 126903, 2024 Mar 22.
Article in English | MEDLINE | ID: mdl-38579224

ABSTRACT

Adiabaticity is crucial for our understanding of complex quantum dynamics and thus for advancing fundamental physics and technology, but its impact cannot yet be quantified in complex but common cases where dynamics is only partially adiabatic, several eigenstates are simultaneously populated and transitions between noneigenstates are of key interest. We construct a universally applicable measure that can quantify the adiabaticity of quantum transitions in an arbitrary basis. Our measure distinguishes transitions that occur due to the adiabatic change of populated system eigenstates from transitions that occur due to beating between several eigenstates and can handle nonadiabatic events. While all quantum dynamics fall within the scope of the measure, we demonstrate its usage and utility through two important material science problems-energy and charge transfer-where adiabaticity could be effected by nuclear motion and its quantification will aid not only in unraveling mechanisms but also in system design, for example, of light harvesting systems.

3.
Sci Total Environ ; 920: 170984, 2024 Apr 10.
Article in English | MEDLINE | ID: mdl-38365025

ABSTRACT

Exposure to elevated particulate matter (PM) concentrations in ambient air has become a major health concern over urban areas worldwide. Reactive oxygen species (ROS) generation due to ambient PM (termed as their oxidative potential, OP) is shown to play a major role in PM-induced health effects. In the present study, the OP of the ambient PM2.5 samples, collected during summer 2019 from New Delhi, were measured using the dithiothreitol (DTT) assay. Average volume-normalized OP (OPV) was 2.9 ± 1.1 nmol DTT min-1 m-3, and mass-normalized OP (OPm) was 61 ± 29 pmol DTT min-1 µg-1. The regression statistics of OPv vs chemical species show the maximum slope of OPV with the elemental carbon (EC, r2 = 0.72) followed by water-soluble organic carbon (WSOC, r2 = 0.72), and organic carbon (OC, r2 = 0.64). A strong positive correlation between OPm and secondary inorganic aerosols (SIA, such as NH4+ and NO3- mass fractions) was also observed, indicating that the sources emitting NO2 and NH3, precursors of NO3- and NH4+, also emit DTT-active species. Interestingly, the slope value of OPv vs OC for aged aerosols (OM/OC > 1.7, f44 > 0.12 and f43 < 0.04) was 1.7 times higher than relatively fresh organic aerosols (OA, OM/OC < 1.7, f44 < 0.12, f43 > 0.04). An increase in OPv and OPoc with f44 indicates the formation of more DTT active species with the ageing of OA. A linear increase in OPoc with increasing Nitrogen/Carbon (N/C) ratio suggests that nitrogenous OA have higher OP.

4.
BMC Infect Dis ; 19(1): 717, 2019 Aug 14.
Article in English | MEDLINE | ID: mdl-31412801

ABSTRACT

BACKGROUND: Coagulase-negative Staphylococci (CoNS) have emerged as a major causative agent of blood-stream infections (BSI). Linezolid (LZD) is currently used for treating glycopeptide and methicillin-resistant staphylococci. It is important to understand the resistance mechanism and probable transmission of LZD resistant (LR) CoNS within the hospital. METHODS: Clinically significant LRCoNS from patients with BSI were characterized using MALDI-TOF and 16S rRNA gene sequence analysis. Antimicrobial susceptibility and MIC of vancomycin and LZD were determined. LZD resistance mechanisms using PCR for the cfr gene and mutation in the V domain of the 23S rRNA gene were studied. RESULTS: The MIC of LZD ranged from 8 to 32 µg/ml. LR was observed in three different CoNS species from diverse locations within the hospital. The cfr gene was identified in all the isolates. Sequence analysis of V domain region of 23S rRNA gene confirmed mutation in single copy among 12/15 isolates with novel mutations: G2614 T and C2384T. All infections were nosocomially acquired and LZD resistance was emerging in the absence of prior LZD use. Horizontal spread of resistant isolates and cfr gene among diverse species were the probable mechanisms of transmission. CONCLUSION: The study highlights the novel mutations associated with LRCoNS and the importance of surveillance & transmission pathway within the hospital. It also systematically discusses the published information on LRCoNS.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteremia/microbiology , Linezolid/pharmacology , Staphylococcal Infections/microbiology , Staphylococcus/drug effects , Adult , Aged , Aged, 80 and over , Bacteremia/drug therapy , Child, Preschool , Coagulase/genetics , Drug Resistance, Bacterial/drug effects , Drug Resistance, Bacterial/genetics , Female , Humans , India , Infant , Male , Microbial Sensitivity Tests , Middle Aged , Mutation , RNA, Ribosomal, 23S/genetics , Staphylococcal Infections/drug therapy , Staphylococcus/genetics , Staphylococcus/isolation & purification
5.
Clin Transl Oncol ; 21(3): 259-267, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30062522

ABSTRACT

Classical protein kinase C (cPKC) enzymes are ser/thr protein kinases that have been an important factor in regulating a variety of cellular functions required for both in terms of health and disease. Therefore, precise control of cPKC-mediated signal is necessary for cellular homeostasis; however, their dysregulation leads to the development of several pathophysiological conditions including cancer. In cellular microenvironment, cPKC-mediated signaling is accompanied by multiple molecular mechanisms including phosphorylation, second messenger binding, and scaffold proteins. Functional cPKC interacts with a number of cellular proteins involved in the regulation of multiple biological functions such as cell growth, survival, migration, and adhesion. Further, the role of cPKC varies from cell to cell, substrate to substrate and, therefore, it is plausible to assume that the dysregulation of cPKC activity causes cellular transformation. Currently, there is no sufficient literature available to provide better understating to develop an effective therapeutic regimen to reverse pathophysiological condition caused by functionally dysregulated cPKC. Therefore, in the present review, we have focused on to provide a better and detail information on the various aspects of cPKC such as structure, mode of activation, regulation, and distinct cellular functions useful for the development of an effective therapeutic regimen against the breast cancer.


Subject(s)
Breast Neoplasms/enzymology , Protein Kinase C/metabolism , Female , Humans
6.
J Clin Diagn Res ; 11(9): DC01-DC05, 2017 Sep.
Article in English | MEDLINE | ID: mdl-29207701

ABSTRACT

INTRODUCTION: Enterococci are part of the normal intestinal flora and have been recognized as important human pathogens. Vancomycin Resistant Enterococci (VRE) are global threat as this resistance is transmissible and also poses a challenge for infection control. AIM: This study was undertaken to study phenotypic and genotypic characteristics of VRE from clinically significant infections among hospitalized patients and their association with gut colonization. MATERIALS AND METHODS: Clinically significant isolates of enterococci (n=250) were studied. Species confirmation was done by Polymerase Chain Reaction (PCR). Minimum Inhibitory Concentration (MIC) for vancomycin was determined by E-test. PCR for VanA, VanB and VanC1 gene was done for genotypic characterization. MIC for teicoplanin, linezolid, tigecycline, daptomycin and quinupristin-dalfopristin was determined by E test. Patients with VRE infection were screened for gut colonization using vancomycin screen agar (6 µg/mL). Continuous data was analysed using the Student's t-test. Categorical data was assessed using Pearson's Chi-square test. A value of p ≤ 0.05 was considered statistically significant. RESULTS: There was good correlation between the phenotypic and genotypic methods used for species identification and detection of vancomycin resistance. E. faecium (162, 64.8%) was most common followed by E. faecalis (82, 32.84%) and E. gallinarum (6, 2.4%). Overall higher resistance was observed among E. faecium. Vancomycin MIC ≥ 2 µg/mL was noted in 63 (25.2%) isolates. Fifty seven isolates showed presence of vanA and vanC1 was detected in six isolates of E. gallinarum. Isolates with VanB genotype was not detected in the present study. MIC50 (µg/mL) for teicoplanin, linezolid, tigecycline, daptomycin and quinupristin-dalfopristrin was 24, 0.75, 0.064, 2 and 0.064 respectively. Resistance to linezolid (1, 1.6%) and tigecycline (2, 3.2%) was rare. Majority (33/47, 70.2%) patients with clinically significant VRE infection showed gut colonization. CONCLUSION: Vancomycin resistance among enterococci is emerging. Emergence of tigecycline and linezolid resistance is also posing a challenge for clinicians. Thus, further investigations are warranted to control vancomycin resistance among pathogens.

7.
BMC Microbiol ; 16(1): 138, 2016 07 08.
Article in English | MEDLINE | ID: mdl-27392139

ABSTRACT

BACKGROUND: Resistance amongst the commensal flora is a serious threat because a very highly populated ecosystem like the gut, may at a later stage, be a source of extra intestinal infections, resistant strains may spread to other host or transfer genetic resistance element to other members of micro-biota including pathogens. This study was carried out to assess fecal colonization by carbapenemase producing Enterobacteriaceae (CPE) and associated risk factors among 100 patients admitted to intensive care unit (ICU). The phenotypic and molecular characterizations of CPE were also included. RESULTS: Colonization with CPE was observed in 6.6 % (8/122) controls. Among ICU patients, fecal carriage of CPE was significantly higher on day 4 (D4) (22 %) as compared to day 1 (D1) (11 %) (p value 0.002). The carbapenemase genes detected included OXA- 48, 181, KPC and NDM-1 with NDM-1 being the predominant carbapenemase in both ICU D1 and D4. Among the 50 CPE isolates, 8 (16 %) were susceptible to meropenem and imipenem (Minimum inhibitory concentration; MIC ≤ 1 mg/L) and all were susceptible to colistin (MIC range 0.125 - 1 mg/L) and tigecycline (MIC range 0.06- 1.5 mg/L). The risk factors associated with CPE carriage were duration of ICU stay, use of ventilator and aminoglycosides. CONCLUSIONS: Prior colonization with CPE could result in their influx and spread in ICU, challenging infection control measures. Exposure to ICU further increases risk of colonization with diverse carbapenemase-producing Enterobacteriaceae. Gut colonization with these strains may be a source of endogenous infection and horizontal transfer of these genes in future.


Subject(s)
Bacterial Proteins/biosynthesis , Enterobacteriaceae/enzymology , Feces/chemistry , Feces/microbiology , beta-Lactamases/biosynthesis , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , DNA, Bacterial/genetics , Drug Resistance, Bacterial , Enterobacteriaceae/drug effects , Enterobacteriaceae/genetics , Enterobacteriaceae/isolation & purification , Enterobacteriaceae Infections/microbiology , Enterobacteriaceae Infections/transmission , Gastrointestinal Microbiome , Humans , India , Infection Control , Intensive Care Units , Microbial Sensitivity Tests , Risk Factors , Tertiary Care Centers , beta-Lactamases/genetics
8.
Indian J Med Microbiol ; 33(4): 576-9, 2015.
Article in English | MEDLINE | ID: mdl-26470968

ABSTRACT

Systemic fungal infection related to fluconazole-resistant yeasts are emerging in immunocompromised patients. In this case-series, we report eight cases of fungemia caused by Trichosporon spp. (2), Stephanoascus ceferrii (1), Kodamaea ohmeri (1), Pichia kutrawersi (2), Candida rugosa (1) and Candida lusitianae (1) in immunocompromised patients. All the yeasts except (Trichosporon asahii) were sequenced. As these rare species are inherently resistant to antifungal agents and they may lead to the development of nosocomial outbreaks, therefore, accurate identification followed by antifungal susceptibility testing is crucial for proper treatment and management.


Subject(s)
Fungemia/diagnosis , Fungemia/microbiology , Hematologic Diseases/complications , Immunocompromised Host , Saccharomycetales/isolation & purification , Trichosporon/isolation & purification , Adolescent , Adult , Antifungal Agents/pharmacology , Drug Resistance, Fungal , Female , Humans , Male , Microbial Sensitivity Tests , Middle Aged , Saccharomycetales/classification , Saccharomycetales/drug effects , Saccharomycetales/genetics , Sequence Analysis, DNA , Trichosporon/classification , Trichosporon/drug effects , Trichosporon/genetics , Young Adult
9.
New Microbes New Infect ; 7: 57-66, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26257914

ABSTRACT

Nosocomial infections are acquired during hospital treatment or in a hospital environment. One such infecting agent, Escherichia coli, harbours many virulence genes that enable it to become pathogenic, causing damage to the host. The mechanism of the E. coli virulence factors provenance to cause infection in host environments is not clearly elucidated. We investigated the virulence and pathogenicity of E. coli affected by the host environment. For this, blood (n = 78) and faecal (n = 83) E. coli isolates were collected from patients with and without sepsis, respectively, who had been admitted to the intensive care unit. The E. coli genomic DNA was isolated; the phylogenetic grouping was conducted by triplex PCR. The occurrence of nine virulence genes among the all the isolates was confirmed by gene-specific PCR. The prevalence of E. coli in blood isolates was more in phylogenetic groups B2 and D compared to groups A and B1. However, in faecal isolates, there was no significant difference. The prevalence of adhesin and toxin (papG, sfa, afa, cnf1, hlyA) genes was higher in blood compared to faecal E. coli isolates. However, the prevalence of aer, traT and PAI was similar as well as higher among both of these groups. These observations indicate a role of external environment (hospital setting) on host susceptibility (development of infection) in the faecal E. coli isolates, thereby making the patient prone to a sepsis condition.

10.
J Parasit Dis ; 39(2): 200-5, 2015 Jun.
Article in English | MEDLINE | ID: mdl-26064000

ABSTRACT

Infection with Haemonchus contortus is one of the most important economic problems in small ruminants worldwide. Resistance development by parasites, drug residues in meat, toxicity, non-availability and high cost limit the usefulness of currently used synthetic drugs. Therefore, the present study was undertaken to evaluate in vitro anthelmintic efficacy of aqueous extract of seeds of Butea monosperma (Lam.) Kuntze against H. contortus. Phytochemical analysis of extract showed high concentration of phenolic (11.93 ± 0.64 mg of GAE/g of extract), flavonoids (238.17 ± 19.14 mg of quercetin/g extract) and tannin (10.80 ± 0.70 mg of GAE/g of extract) content. The observations revealed that parasites were sluggish and movement was little at 4 h post exposure of 25, 50 mg/ml and very sluggish in 100 mg/ml concentration. The extract showed complete mortality of the adult H. contortus worms at the concentrations of 100 mg/ml at the time exposure of 6 h and with the concentration of 50 mg/ml at the post exposure of 8 h. At 25 mg/ml concentration 50 % mortality was recorded at 6 h and complete at 8 h post exposure. The LC50 at 6 and 8 h were 45.20 and 17.50 mg/ml respectively. Levamisole at concentration of 0.5 mg/ml caused 50 % mortality at 2 h post exposure and full mortality at 4 h post exposure. These cidal effects may be due to presence of high phenolic, flavonoids and tannin content in the extract. The results confirm the aqueous extract of B. monosperma (Lam.) Kuntze on adult H. contortus worms.

11.
Exp Appl Acarol ; 67(1): 147-57, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26071101

ABSTRACT

Detection of resistance levels against deltamethrin and cypermethrin in Rhipicephalus (Boophilus) microplus collected from Jammu (India) was carried out using larval packet test (LPT). The results showed the presence of resistance level II and I against deltamethrin and cypermethrin, respectively. Adult immersion test (AIT) and LPT were used to evaluate the in vitro efficacy of ethanolic and aqueous floral extracts of Calendula officinalis against synthetic pyrethroid resistant adults and larvae of R. (B.) microplus. Four concentrations (1.25, 2.5, 5 and 10 %) of each extract with four replications for each concentration were used in both the bioassays. A concentration dependent mortality was observed and it was more marked with ethanolic extract. In AIT, the LC50 values for ethanolic and aqueous extracts were calculated as 9.9 and 12.9 %, respectively. The egg weight of the live ticks treated with different concentrations of the ethanolic and aqueous extracts was significantly lower than that of control ticks; consequently, the reproductive index and the percent inhibition of oviposition values of the treated ticks were reduced. The complete inhibition of hatching was recorded at 10 % of ethanolic extract. The 10 % extracts caused 100 % mortality of larvae after 24 h. In LPT, the LC50 values for ethanolic and aqueous extracts were determined to be 2.6 and 3.2 %, respectively. It can be concluded that the ethanolic extract of C. officinalis had better acaricidal properties against adults and larvae of R. (B.) microplus than the aqueous extract.


Subject(s)
Acaricides/pharmacology , Calendula/chemistry , Plant Extracts/pharmacology , Rhipicephalus/drug effects , Animals , Female , Flowers/chemistry , India , Larva/drug effects , Nitriles/pharmacology , Pyrethrins/pharmacology , Rhipicephalus/growth & development
12.
Exp Appl Acarol ; 65(1): 141-8, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25039005

ABSTRACT

The aim of the study was to evaluate the in vitro efficacy of different concentrations of ethanolic extract obtained from the aerial parts of Artemisia absinthium in comparison to amitraz on adults, eggs and larvae of Hyalomma anatolicum using the adult immersion test (AIT), egg hatchability test and larval packet test (LPT), respectively. Four concentrations of the extract (2.5, 5, 10 and 20%) with three replications for each concentration were used in all the bioassays. In AIT, the mortality rates at 2.5, 5 and 10% were significantly different (p < 0.05) in comparison to the control group; however, at 20%, it was similar to the positive control group. Maximum mortality of 86.7% was recorded at 20%. The LC50 and LC95 values were calculated as 6.51 and 55.43%, respectively. The oviposition was reduced significantly by 36.8 and 59.1% at concentrations of 10 and 20%, respectively. Egg hatchability was reduced significantly at all concentrations (2.5-20%) in comparison to the control. In LPT, the extract caused 100% mortality of larvae at all the concentrations after 24 h. The results show that ethanolic extract obtained from the aerial parts of A. absinthium has acaricidal properties and could be useful in controlling H. anatolicum.


Subject(s)
Acaricides/pharmacology , Artemisia absinthium/chemistry , Ethanol/chemistry , Plant Extracts/pharmacology , Ticks/drug effects , Acaricides/chemistry , Animals , Female , Larva/drug effects , Ovum/drug effects , Plant Components, Aerial/chemistry , Plant Extracts/chemistry
13.
Plant Biol (Stuttg) ; 17(3): 608-17, 2015 May.
Article in English | MEDLINE | ID: mdl-25311688

ABSTRACT

Sucrose synthesis/accumulation in sugarcane is a complex process involving many genes and regulatory sequences that control biochemical events in source-sink tissues. Among these, sucrose synthase (SuSy), sucrose phosphate synthase (SPS), soluble acid (SAI) and cell wall (CWI) invertases are important. Expression of these enzymes was compared in an early (CoJ64) and late (BO91) maturing sugarcane variety using end-point and qRT-PCR. Quantitative RT-PCR at four crop stages revealed high CWI expression in upper internodes of CoJ64, which declined significantly in both top and bottom internodes with maturity. In BO91, CWI expression was high in top and bottom internodes and declined significantly only in top internodes as the crop matured. Overall, CWI expression was higher in CoJ64 than in BO91. During crop growth, there was no significant change in SPS expression in bottom internodes in CoJ64, whereas in BO91 it decreased significantly. Apart from a significant decrease in expression of SuSy in mature bottom internodes of BO91, there was no significant change. Similar SAI expression was observed with both end-point and RT-PCR, except for significantly increased expression in top internodes of CoJ64 with maturity. SAI, being a major sucrose hydrolysing enzyme, was also monitored with end-point PCR expression in internode tissues of CoJ64 and BO91, with higher expression of SAI in BO91 at early crop stages. Enzyme inhibitors, e.g. manganese chloride (Mn(++) ), significantly suppressed expression of SAI in both early- and late-maturing varieties. Present findings enhance understanding of critical sucrose metabolic gene expression in sugarcane varieties differing in content and time of peak sucrose storage. Thus, through employing these genes, improvement of sugarcane sucrose content is possible.


Subject(s)
Gene Expression , Genes, Plant , Plant Development , Plant Proteins/genetics , Plant Stems/metabolism , Saccharum/genetics , Sucrose/metabolism , Cell Wall/metabolism , Crops, Agricultural , Gene Expression Regulation, Plant , Glucosyltransferases/genetics , Glucosyltransferases/metabolism , Hybridization, Genetic , Molecular Sequence Data , Plant Proteins/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Saccharum/enzymology , Saccharum/growth & development , Saccharum/metabolism , Species Specificity , beta-Fructofuranosidase/genetics , beta-Fructofuranosidase/metabolism
14.
ScientificWorldJournal ; 2014: 858973, 2014.
Article in English | MEDLINE | ID: mdl-25525626

ABSTRACT

In vitro efficacy of ethanolic extracts obtained from the aerial parts of Ageratum conyzoides and Artemisia absinthium was assessed on Rhipicephalus microplus using adult immersion test (AIT). Five concentrations of the extract (1.25%, 2.5%, 5%, 10%, and 20%) with three replications for each concentration were used in the bioassay. In AIT, the maximum mortality was recorded as 40% and 66.7% at 20% concentration for A. conyzoides and A. absinthium, respectively. Acaricidal activity was found to be higher in the extract of A. absinthium with LC50 and LC95 values of 11.2% and 61.7%, respectively. Egg mass weight of the live ticks treated with different concentrations of the extracts was significantly (P<0.05) lower than that of control ticks; consequently, the reproductive index and oviposition values of the treated ticks were reduced significantly (P<0.05). The A. conyzoides inhibited 90% hatching of eggs at the 20% concentration, whereas A. absinthium showed 100% inhibition at 5%, 10%, and 20% concentrations. The results show that A. absinthium has better acaricidal properties than A. conyzoides and could be useful in controlling R. microplus.


Subject(s)
Acaricides/pharmacology , Ageratum/chemistry , Artemisia absinthium/chemistry , Ethanol/chemistry , Plant Extracts/pharmacology , Rhipicephalus/drug effects , Animals , Body Weight/drug effects , Cattle , Dose-Response Relationship, Drug , Oviposition/drug effects , Ovum/drug effects , Phytotherapy , Regression Analysis , Reproduction/drug effects
15.
J Phys Chem A ; 118(22): 3996-4004, 2014 Jun 05.
Article in English | MEDLINE | ID: mdl-24815040

ABSTRACT

Straight chain amide N,N-dihexyloctanamide (DHOA) has been found to be a promising alternative extractant to tri-n-butyl phosphate (TBP) for the reprocessing of irradiated uranium- and thorium-based fuels. Unlike TBP, DHOA displays preferential extraction of Pu(IV) over U(VI) at higher acidities (≥3 M HNO3) and poor extraction at lower acidities. Density functional theory (DFT) based calculations have been carried out on the structures and relative binding energies of U(VI) and Pu(IV) with the extractant molecules. These calculations suggest that the differential hardness of the two extractants is responsible for the preferential binding/complexation of TBP to uranyl, whereas the softer DHOA and the bulky nature of the extractant lead to stronger binding/complexation of DHOA to Pu(IV). In conjunction with quantum chemical calculations, small angle neutron scattering (SANS) measurements have also been performed for understanding the stoichiometry of the complex formed that leads to relatively lower extraction of Th(IV) (a model for Pu(IV)) as compared to U(VI) using DHOA and TBP as the extractants. The combined experimental and theoretical studies helped us to understand the superior complexation/extraction behavior of Pu(IV) over U(VI) with DHOA.

16.
Environ Sci Process Impacts ; 16(4): 904-15, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24531276

ABSTRACT

The presence of long-lived radionuclides in natural aquatic systems is of great environmental concern in view of their possible migration into biospheres of mankind. Trivalent actinides such as (241/243)Am can contribute a great deal to radioactivity for several thousand years. This migration is significantly influenced by various factors such as pH, complexing ions present in aquatic environments, and the sorption of species involving radionuclides by sediments around water bodies. Clay minerals such as bentonite are known to be highly efficient in radionuclide retention and hence are suitable candidates for backfill materials. This study presents experimental results on the interaction of Eu(iii) and Gd(iii) (chemical analogs of Am(iii) and Cm(iii)) with bentonite clay under varying experimental conditions of contact time, pH, and the presence of complexing anions such as humic acid (HA) and citric acid (cit). The sorption of HA on bentonite decreased with increasing the pH from 2 to 8, which was attributed to electrostatic interactions between HA and the bentonite surfaces. The sorption of Eu(iii) on bentonite colloids showed marginal variation with pH (>95%). However, a decrease in Eu(iii) sorption was observed in the presence of HA beyond pH 5 due to the increased aqueous complexation of Eu(iii) with deprotonated HA in the aqueous phase. The complexation of Eu(iii) with citrate ions was studied using Time Resolved Laser induced Fluorescence Spectroscopy (TRLFS) to explain the sorption data. Extended X-ray absorption fine structure (EXAFS) and electron paramagnetic resonance (EPR) investigations were carried out to understand the local chemical environment surrounding Eu(iii) and Gd(iii) (EPR probe) sorbed on bentonite under different experimental conditions. Surface complexation modelling shows the predominant formation of ≡XOEu(+2) (silanol) up to pH < 7, and beyond which ≡YOEu(OH)(+) (aluminol) is responsible for the quantitative sorption of Eu(iii) onto bentonite in the studied pH range.


Subject(s)
Bentonite/chemistry , Humic Substances , Metals/chemistry , Models, Chemical , Hydrogen-Ion Concentration , Ions/chemistry , Spectrometry, Fluorescence , X-Ray Absorption Spectroscopy
17.
J Helminthol ; 88(3): 357-61, 2014 Sep.
Article in English | MEDLINE | ID: mdl-23721888

ABSTRACT

The neuromuscular system of helminths is an important area for target identification and drug development. Many anthelmintics, namely ivermectin, levamisole, piperazine, pyrantel, praziquantel and organophosphates, produce paralysis of helminths by affecting their neuromuscular systems. The neuromuscular system of helminths is also an important area of research to identify some of the important differences between the neuromuscular physiology of helminths and mammals. The identification of differences would help in developing newer target-specific, safe and effective anthelmintics. The present study was carried out to investigate the effects of different adrenergic neurotransmitters (epinephrine, norepinephrine, dopamine, l-dopa) and their antagonists (propranolol and haloperidol) on the spontaneous muscular activity of isometrically mounted Paramphistomum cervi.


Subject(s)
Adrenergic Agents/metabolism , Adrenergic beta-Antagonists/metabolism , Dopamine Antagonists/metabolism , Locomotion , Muscles/physiology , Neurotransmitter Agents/metabolism , Paramphistomatidae/physiology , Animals
18.
Ultrasound ; 22(1): 26-36, 2014 Feb.
Article in English | MEDLINE | ID: mdl-27433190

ABSTRACT

National guidelines for routine ultrasound quality assurance include the measurement of transducer sensitivity using the in-air reverberation pattern generated from a transducer operating in air. The in-air reverberation method has been compared with other well-known measures of transducer sensitivity, such as the Sonora FirstCall probe tester (Sonora Medical Systems Inc, Longmont, CO, USA) and phantom-based images. There is good agreement between the in-air reverberation images and the Sonora FirstCall probe data for individual crystal sensitivity. However, the in-air reverberation approach is cheaper and easier to implement for linear and curvilinear transducers. The methods used for measuring the in-air reverberation pattern and the influence of scanner parameters such as gain and output power have been investigated. In general, reliance on a visual assessment of reverberation depth can lead to inconsistencies in the measurement of reverberation depth, when taken over a period of several months. The value of scanner parameters, in particular scanner gain, is also important when trying to measure changes in reverberation depth due to changes in transducer performance. A more accurate assessment of changes in transducer sensitivity, using the in-air reverberation method, is found by measuring the peak pixel grey scale values within a chosen reverberation band in the image. This quantitative approach can be taken a step further by assessing changes within the whole in-air reverberation pattern, by applying a two-dimensional cross correlation between two reverberation images to assess changes in transducer performance.

19.
Ultrasound ; 22(1): 61-5, 2014 Feb.
Article in English | MEDLINE | ID: mdl-27433195

ABSTRACT

Management of ultrasound equipment at Sheffield Teaching Hospitals NHS Foundation Trust is described. The organisation and input of various stakeholders and their involvement with ultrasound equipment management and scientific ultrasound is discussed. Two important stakeholders are the Medical Equipment Management Group and the Radiation Safety Steering Committee. The Medical Equipment Management Group has a specific sub-group, the Ultrasound sub-group, and its role is to coordinate the purchase, replacement and quality assurance of ultrasound equipment in the Trust. The Radiation Safety Steering Committee has a non-ionising radiation representative and the role of this committee is to provide corporate assurance that any health and safety issues arising from the use of radiation to either patients, members of the public or staff within the Trust are being effectively managed. The Ultrasound sub-group of the Medical Equipment Management Group has successfully brought together management of all ultrasound equipment within the Trust and is in the process of fulfilling the quality assurance and training milestones set out by the Medical Equipment Management Group. Advice from the Radiation Safety Steering Committee has helped to increase awareness of ultrasound safety and good scanning practice, especially in the case of neonatal ultrasound imaging, within the Trust. In addition, the RSSC has given advice on clinical pathways for patients undergoing ionising radiation imaging while being treated by extra-corporeal shockwave lithotripsy.

20.
Parasitol Res ; 113(2): 747-54, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24288053

ABSTRACT

The objective of the study was to evaluate the in vitro efficacy of different concentrations of chloroform extract obtained from the aerial parts of Artemisia absinthium in comparison to amitraz on adults, eggs and larvae of the dog tick Rhipicephalus sanguineus using the adult immersion test (AIT), egg hatchability test (EHT) and larval packet test (LPT), respectively. Five concentrations of the extract (1.25, 2.5, 5, 10 and 20 %) with three replications for each concentration were used in all the bioassays. A control group was established (water + dimethylsulphoxide) together with a positive control group (amitraz), with three repetitions each. In AIT, the mortality rates were 0.0, 13.3, 16.7, 33.3 and 93.3 % in concentrations of 1.25, 2.5, 5, 10 and 20 %, respectively, and the variation was significant (p=0.0151). The LC50 (CI) and LC95 (CI) values were calculated as 8.793 % (8.217-9.408) and 34.59 % (29.71-40.26), respectively. The egg production was reduced by 6.6, 6.6, 18.3, 42.5 and 85.1 % in the concentrations of 1.25, 2.5, 5, 10 and 20 %, respectively, and it was statistically significant (p=0.0274). In EHT, hatching was completely inhibited at 5, 10 and 20 % displaying 100 % ovicidal action while at the concentrations of 1.25 and 2.5 %, the inhibition rates were 20 and 60 %, respectively. In LPT, the extract caused 100 % mortality of larvae in the concentrations of 5, 10 and 20 % after 24 h while at the concentrations of 1.25 and 2.5 %, the mortality rates were 54.3 and 96.7 %, respectively. The LC50 (CI) and LC95 (CI) values were determined to be 1.11 % (1.099-1.121) and 2.37 % (2.328-2.423), respectively. The results show that the extract of A. absinthium has acaricidal properties and could be useful in controlling R. sanguineus which is an efficient vector of pathogens both in dogs and humans.


Subject(s)
Acaricides , Artemisia absinthium/chemistry , Plant Extracts , Rhipicephalus sanguineus , Animals , Dogs , Female , Larva , Oils, Volatile , Ovum , Toluidines
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