434 research outputs found

    Seed dormancy and endogenous growth substances in Anab-e-Shahi grapes

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    Auxin, gibberellin and inhibitor contents were estimated in the freshly extracted seeds as well as in those moist stratified for 30, 45, 60, 75 and 90 days. The maximum seed germination was obtained when the seeds were stratified for 60 days. Auxin activity increased with the increase in the period of stratification and was found to be at its maximum in the germinating seeds. Fully ripe freshly extracted seeds did not show any gibberellin-like activity. It was maximum in the extracts of the seeds moist-stratified for 60 days. Abscisic acid-like inhibitor was present in the extracts of the fully ripe fresh seeds. Its quantity decreased with the period of stratification and was minimum when the seeds were stratified for 45 and 90 days. From these studies, it may be postulated that the seed germination in grapes is regulated by the appearance of growth promoting substances like auxins and gibberellins during stratification and disappearance of inhibitors like abscisic acid. In all the cultivars, stratification for 60 days was sufficient to create these conditions for the best seed germination.Samenruhe und endogene Wachstumsregulatoren bei der Rebensorte Anab-e-ShahiDer Gehalt an Auxin, Gibberellin und Hemmstoffen in frisch isolierten Samen von Anab-e-Shahi sowie in Samen, die 30, 45, 60, 75 und 90 Tage lang feucht stratifiziert worden waren, wurde bestimmt. Durch 60tägige Stratifikation wurde die Keimung am stärksten gefördert. Mit der Dauer der Stratifikation nahm auch die Auxinaktivität zu, um ihr Maximum in den keimenden Samen zu erreichen. Voll ausgereifte, frisch isolierte Samen zeigten keinerlei Gibberellin-artige Aktivität. Eine solche war in den Extrakten von Samen, die 60 Tage lang feucht stratifiziert worden waren, im Maximum vorhanden. In den Extrakten voll ausgereifter, frischer Samen trat ein Abscisinsäure-artiger Hemmstoff auf. Seine Konzentration nahm mit fortschreitender Stratifikation ab und erreichte ihr Minimum nach 45 und 90 Tagen. Aufgrund der vorliegenden Untersuchungen kann angenommen werden, daß die Samenkeimung bei Reben durch das verstärkte Auftreten wachstumsfördernder Substanzen wie Auxine und Gibberelline im Laufe der Stratifikation und den Rückgang Abscisinsäure-artiger Hemmstoffe reguliert wird. Auch bei anderen Rebensorten genügte durchweg eine 60tägige Stratifikation, um die bestmöglichen Bedingungen für die Samenkeimung zu schaffen

    Effect of vitamin C on N,N′-dimethyl-4,4′-bipyridinium dichloride-induced hepatic and renal toxicity in Swiss albino mice

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    Purpose: To evaluate the effectiveness of vitamin C on paraquat-induced hepatic and renal toxicity in Swiss albino mice.Methods: Three groups of Swiss albino mice (n = 10), i.e., control, paraquat (15 mg/kg) and paraquat (15 mg/kg) + vitamin C (20 mg/kg) were used in the study. The drugs were administered intraperitoneally for four days. Blood samples were collected on day 5 for determination of serum levels of liver and renal biomarkers. Thereafter, the animals were sacrificed; liver and kidney were excised and preserved in neutral formalin for histopathological analysis.Results: The paraquat-treated animals showed higher levels of aspartate transaminase (AST), alanine transaminase (ALT), serum urea and creatinine, relative to values for control. Histopathological examination of the paraquat-treated animals showed cytoplasmic vacuolar degeneration and congestion of central vein in the liver, and glomerular necrosis in the kidneys. Control and vitamin C-treated mice showed normal architecture of liver and kidney.Conclusion: These results indicate that vitamin C modulated the paraquat-induced liver and renal abnormalities in the experimental animals. Thus vitamin C exerts hepatoprotective and renoprotective effects against paraquat poisoning.Keywords: Paraquat poisoning, Liver, Kidney, Vitamin C, Toxicity, Histopatholog

    The incidence and intensity of postendodontic pain and flareup in single and multiple visit root canal treatments: a systematic review and meta-analysis

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    To assess the incidence and intensity of postendodontic pain and flareup in single and multiple visit root canal treatment (RCT) and determine if the difference between the two is significant, a search of PubMed, Medline, Embase, Cochrane, Scopus and Web of science was conducted. The grey literature was searched using Google Scholar and Saudi digital library. Randomised controlled trials evaluating the incidence and intensity of postendodontic pain and flareup published in English from 1 January 2000 to 15 April 2020 were searched. The PRISMA protocol was followed to select the articles. A random effects model was used for the meta-analysis of the data in the included studies. Twenty-one articles were included in the review. Three compared both the incidence and the intensity, while the rest compared either one of the parameters. Most studies used both hand-driven and rotary instruments and irrigated with sodium hypochlorite. Twelve studies used an intracanal medicament. Although individual studies showed discordant treatment outcomes, the meta-analysis did not reveal any significant difference in the incidence or the intensity of the postendodontic flareup between the single and multiple visit RCT groups. Single or a multiple visit root canal treatment is not an independent determinant for the risk of postendodontic pain or a flareup

    Impact of couple stress and variable viscosity on heat transfer and flow between two parallel plates in conducting field

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    This study explores the flow properties of a couple stress fluid with the consideration of variable viscosity and a uniform transverse magnetic field. Under the effect of irreversible heat transfer, a steady fluid flow has taken place between two parallel inclined plates. The fluid flows due to gravity and the constant pressure gradient force. The plates are fixed and isothermal. The governing equations have been solved analytically for velocity and temperature fields. The total rate of heat flow and volume flow across the channel, skin friction, and Nusselt number at both plates are calculated and represent the impacts of relevant parameters through tables and graphs. The findings show that velocity, temperature, and the total rate of heat flow across the channel are enhanced by increasing the couple stress parameter and the viscosity variation parameter, while increasing the values of the Hartmann number reduces them

    Hygienic quality of dehydrated aromatic herbs marketed in Southern Portugal

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    Dehydrated aromatic herbs are highly valued ingredients, widely used at home level and by food processing industry, frequently added to a great number of recipes in the Mediterranean countries. Despite being considered low-moisture products and classified as GRAS, during pre and post-harvesting stages of production they are susceptible of microbial contamination. In Europe an increasing number of food recalls and disease outbreaks associated with dehydrated herbs have been reported in recent years. In this study the microbial quality of 99 samples of aromatic herbs (bay leaves, basil, coriander, oregano, parsley, Provence herbs, rosemary and thyme) collected from retails shops in the region of Algarve (Southern Portugal) was assessed. All the samples were tested by conventional methods and were assayed for the total count of aerobic mesophilic microorganisms, Salmonella spp., Escherichia coli, coagulase-positive staphylococci and filamentous fungi. Almost 50 % of the herbs did not exceed the aerobic mesophilic level of 104 CFU/g. The fungi count regarded as unacceptable (106 CFU/g) was not found in any of the tested herbs, while 84 % of the samples ranged from ≤102 to 104 CFU/g. No sample was positive for the presence of Salmonella spp., Escherichia coli and staphylococci. The results are in compliance with the European Commission criteria although they point out to the permanent need of surveillance on the good standards of handling/cooking practices as well as the importance of avoiding contamination at production, retailing and distribution. The microbiological hazards associated with the pathogenic and toxigenic microbiota of dried herbs remain as a relevant public health issue, due to the fact that they are added to foods not submitted to any following lethal procedure. Control measures should be adopted in order to ensure that all phases of their supply chain respect the food safety standards.FCT: UID/BIA/04325/2019.info:eu-repo/semantics/publishedVersio

    Commissioning and First Operation of the Antiproton Decelerator (AD)

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    The Antiproton Decelerator (AD) is a simplified source of antiprotons which provides low energy antiprotons for experiments, replacing four machines: AC (Antiproton Collector), AA (Antiproton Accumulator), PS and LEAR (Low Energy Antiproton Ring), shutdown in 1996. The former AC was modified to include deceleration and electron cooling. The AD started operation in July 2000 and has since delivered cooled beam at 100 MeV/c (kinetic energy of 5.3 MeV) to 3 experiments (ASACUSA, ATHENA and ATRAP) for 1500 h. The flux (up to 2.5´105pbars /s delivered in short pulses of 330 ns every 110 s) and the quality of the ejected beam are not far from the design specifications. A linear RF Quadrupole Decelerator (RFQD) was commissioned in November 2000 to post-decelerate the beam for ASACUSA from 5.3 MeV to about 15 keV. Problems encountered in converting the fixed energy AC into a decelerating machine will be outlined, and the present status of the AD, including the performance of the cooling systems and the special diagnostics to cope with beams of less than 107 pbars, will be reviewed. Possible future developments will be sketche

    Casting a Wide Net: HIV Drug Resistance Monitoring in Pre-Exposure Prophylaxis Seroconverters in the Global Evaluation of Microbicide Sensitivity Project

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    Background: Evidence of HIV drug resistance (HIVDR) in individuals using oral pre-exposure prophylaxis (PrEP) who acquire HIV is limited to clinical trials and case studies. More data are needed to understand the risk of HIVDR with oral PrEP during PrEP rollout. Mechanisms to collect these data vary, and are dependent on cost, scale of PrEP distribution, and in-country infrastructure for the identification, collection, and testing of samples from PrEP seroconverters. / Methods: The Global Evaluation of Microbicide Sensitivity (GEMS) project, in collaboration with country stakeholders, initiated HIVDR monitoring among new HIV seroconverters with prior PrEP use in Eswatini, Kenya, South Africa, and Zimbabwe. Standalone protocols were developed to assess HIVDR among a national sample of PrEP users. In addition, HIVDR testing was incorporated into existing demonstration projects for key populations. / Lessons learned: Countries are supportive of conducting a timelimited evaluation of HIVDR during the early stages of PrEP rollout. As PrEP rollout expands, the need for long-term HIVDR monitoring with PrEP will need to be balanced with maintaining national HIV drug resistance surveillance for pretreatment and acquired drug resistance. Laboratory capacity is a common obstacle to setting up a monitoring system. / Conclusions: Establishing HIV resistance monitoring within PrEP programs is feasible. Approaches to drug resistance monitoring may evolve as the PrEP programs mature and expand. The methods and implementation support offered by GEMS assisted countries in developing methods to monitor for drug resistance that best fit their PrEP program needs and resources

    An Antiproton Decelerator in the CERN PS Complex

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    The present CERN PS low-energy antiproton complex involves 4 machines to collect, cool, decelerate and supply experiments with up to 1010 antiprotons per pulse and per hour of momenta ranging from 0.1 to 2 GeV/c. In view of a possible future physics programme requiring low energy antiprotons, mainly to carry out studies on antihydrogen, a simplified scheme providing at low cost antiprotons at 100 MeV/c has been studied. It requires only one machine, the present Antiproton Collector (AC) converted into a cooler and decelerator (Antiproton Decelerator, AD) and delivering beam to experiments in the hall of the present Antiproton Accumulator Complex (AAC) [1]. This paper describes the feasibility study of such a scheme [2]

    The antiproton decelerator (AD), a simplified antiproton source (feasibility study)

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    In view of a possible future physics programme concerning antihydrogen a simplified scheme for the provision of antiprotons of a few MeV has been studied. It uses the present target area and the modified Antiproton Collector (AC) in its present location. In this report all the systems are reviewed and their modifications discussed
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