898 research outputs found
Research Update: Density functional theory investigation of the interactions of silver nanoclusters with guanine
Citation: Dale, B. B., Senanayake, R. D., & Aikens, C. M. (2017). Research Update: Density functional theory investigation of the interactions of silver nanoclusters with guanine. APL Materials, 5(5). doi:10.1063/1.4977795Bare and guanine-complexed silver clusters Agnz (n = 2-6; z = 0-2) are examined using density functional theory to elucidate the geometries and binding motifs that are present experimentally. Whereas the neutral systems remain planar in this size range, a 2D-3D transition occurs at Ag5+ for the cationic system and at Ag42+ for the dicationic system. Neutral silver clusters can bind with nitrogen 3 or with the pi system of the base. However, positively charged clusters interact with nitrogen 7 and the neighboring carbonyl group. Thus, the cationic silver-DNA clusters present experimentally may preferentially interact at these sites. © 2017 Author(s)
Estimation of body weight using anthropometric parameters in Sri Lankan hospitalized adult patients
Body weight is an important clinical parameter for accurate dosing of drugs with a narrow therapeutic window, However, it is difficult to measure the body weight of a patient if they cannot stand on a scale. There are several anthropometrics-based equations to estimate the body weight, but most of these are derived from white Caucasian populations and are not validated for South Asians. This study aimed to validate existing anthropometrics-based weight estimation equations and develop a new equation for the same purpose for Sri Lankan adults. This prospective study was conducted at the National Hospital of Sri Lanka over a 6-month period, split into a development and a validation phase. During the development phase, estimated body weight of patients by doctors and nurses and patients themselves were noted and compared against their actual body weight. In addition, 13 anthropometric measurements were taken, which were used to validate 12 anthropometrics-based equations to estimate body weight described in literature previously. Two new gender specific regression models to estimate the body weight in the local population was also derived and validated. A total of 502 (males = 249) and 217 (males = 108) patients were recruited for the development and validation phases respectively. Both doctors and patients had comparable accuracy in predicting body weight (p>0.05). All anthropometric based equations were significantly correlated with actual body weight (correlation coefficients: 0.741–0.869), and the new equations derived from the local data performed similarly to the best performing equation identified from the literature during validation phase. However, even the best of these equations could not outperform patient/physician estimates. When the patient weight cannot be measured, an estimate by the patient or the doctor may be the best substitute
Micron Size Laser-Wire System at the ATF Extraction Line, Recent Results and ATF-II Upgrade
The KEK Accelerator test facility (ATF) extraction line laser-wire system has been upgraded last year allowing the measurement of micron scale transverse size electron beams. The most recent measurements using the upgraded system are presented. The ATF-II extraction line design call for the major upgrade of the existing laser-wire system. We report on the hardware upgrades, including the major hardware upgrades to the laser transport, the laser beam diagnostics line, and the mechanical control systems
Outcomes of stroke patients undergoing thrombolysis in Sri Lanka; an observational prospective study from a low-middle income country
Background: Stroke related deaths are relatively higher in low- and middle-income countries where only a fraction of eligible patients undergo thrombolysis. There is also limited evidence on post-thrombolysis outcomes of patients from Asian countries in these income bands. Methods: This is a single center prospective observational study of a patient cohort with acute ischaemic stroke, undergoing thrombolysis with alteplase (low and standard dose), over a 24-month period in 2019/2020. Modified Rankin scale (mRS) for dependency at 3 months (primary outcome), duration of hospital stay, incidence of symptomatic intracranial haemorrhages and all-cause mortality at 3 months (secondary outcomes) were recorded. Demographic, clinical and treatment related factors associated with these outcomes were explored. Results: Eighty-nine patients (males – 61, 69%, mean age: 60 years ±12.18) were recruited. Time from symptom onset to reperfusion was 174 min ± 56.50. Fifty-one patients were independent according to mRS, 11 (12.4%) patients died, and 11 (12.5%) developed symptomatic intracranial haemorrhages by 3 months. Functional independence at 3 months was independently associated with National Institutes of Health Stroke Scale (NIHSS) on admission (p < 0.05). Thrombolysis with low dose alteplase did not lead to better or worse outcomes compared to standard dose. Conclusions: On admission NIHSS is predictive of functional independence at 3 months post-thrombolysis. Low dose alteplase may be as efficacious as standard dose alteplase with associated cost savings, but this needs to be confirmed by a prospective clinical trial for the Sri Lankan population
WWER-1000 Nuclear reactor simulator for education. Part A': Overview of simulator physico-mathematical model components
A review of phylogenetic studies carried out together with morphological ones shows that a major problem with most early studies is that they concentrated on techniques and used material or strains of fungi that in most cases were not carefully reference, and in a worrying number of cases wrongly named. Most classical species, particularly of microfungi, are not represented by adequate type material, or other authoritatively identified cultures or specimens, that can serve as DNA sources for phylogenetic study, or for developing robust identification systems. Natural classifications of fungi therefore suffer from the lack of reference strains in resultant phylogenetic trees. In some cases, epitypification and neotypification can solve this problem and these tools are increasingly used to resolve taxonomic confusion and stabilize the understanding of species, genera, families, or orders of fungi. This manuscript discusses epitypification and neotypification, describes how to epitypify or neotypify species and examines the importance of this process. A set of guidelines for epitypification is presented. Examples where taxa have been epitypified are presented and the benefits and problems of epitypification are discussed. As examples of epitypification, or to provide reference specimens, a new epitype is designated for Paraphaeosphaeria michotii and reference specimens are provided for Astrosphaeriella stellata, A. bakeriana, Phaeosphaeria elongata, Ophiobolus cirsii, and O. erythrosporus. In this way we demonstrate how to epitypify taxa and its importance, and also illustrate the value of proposing reference specimens if epitypification is not advisable. Although we provided guidelines for epitypification, the decision to epitypify or not lies with the author, who should have experience of the fungus concerned. This responsibility is to be taken seriously, as once a later typification is made, it may not be possible to undo that, particularly in the case of epitypes, without using the lengthy and tedious formal conservation and rejection processes
Comparison of bio-inspired algorithms applied to the coordination of mobile robots considering the energy consumption
Many applications, related to autonomous mobile robots, require to explore in an unknown environment searching for static targets, without any a priori information about the environment topology and target locations. Targets in such rescue missions can be fire, mines, human victims, or dangerous material that the robots have to handle. In these scenarios, some cooperation among the robots is required for accomplishing the mission. This paper focuses on the application of different bio-inspired metaheuristics for the coordination of a swarm of mobile robots that have to explore an unknown area in order to rescue and handle cooperatively some distributed targets. This problem is formulated by first defining an optimization model and then considering two sub-problems: exploration and recruiting. Firstly, the environment is incrementally explored by robots using a modified version of ant colony optimization. Then, when a robot detects a target, a recruiting mechanism is carried out to recruit a certain number of robots to deal with the found target together. For this latter purpose, we have proposed and compared three approaches based on three different bio-inspired algorithms (Firefly Algorithm, Particle Swarm Optimization, and Artificial Bee Algorithm). A computational study and extensive simulations have been carried out to assess the behavior of the proposed approaches and to analyze their performance in terms of total energy consumed by the robots to complete the mission. Simulation results indicate that the firefly-based strategy usually provides superior performance and can reduce the wastage of energy, especially in complex scenarios
Metabolic dysfunctions in multiple sclerosis: implications as to causation, early detection, and treatment, a case control study
BACKGROUND: Biochemical changes associated with multiple sclerosis (MS), and its various clinical forms have not been characterized well. Therefore, we investigated the biochemistry of MS in relation to its natural history using targeted lipidomics platforms. METHODS: Cross-sectional serum samples from 24 secondary progressive (SPMS), 100 relapsing remitting (RRMS), 19 primary progressive MS (PPMS), and 55 age-matched control subjects were analyzed by flow injection tandem mass spectrometry for very long chain fatty acid (VLCFA) containing phosphatidyl ethanolamines (PtdEtn), plasmalogen ethanolamines (PlsEtn) and for novel anti-inflammatory gastrointestinal tract acids (GTAs). Changes in analyte levels relative to healthy controls were correlated with the disease stage and disease duration. RESULTS: RRMS subjects having <13 years disease duration had elevated levels (p < 0.05) of anti-inflammatory metabolites (GTAs) and normal levels (p > 0.05) of mitochondrial stress biomarkers (VLCFA-PtdEtn), compared to controls. SPMS subjects had statistically similar levels of anti-inflammatory metabolites (GTAs), elevated mitochondrial stress metabolites (VLCFA-PtdEtn) and elevated peroxisomal metabolites (PlsEtn) compared to controls (p < 0.05). RRMS subjects with > = 13 years disease duration exhibited metabolic profiles intermediate between short-duration RRMS and SPMS, based on statistical significance. Therefore, RRMS cohort appear to comprise of two metabolically distinct subpopulations. The key clinical discriminator of these two groups was disease duration. PPMS patients exhibited metabolic profiles distinct from RRMS and SPMS. CONCLUSIONS: These data indicate that inflammation and mitochondrial stress are intricately involved in the etiology of MS and that progression in MS can potentially be monitored using serum metabolic biomarkers
The economic implications of introducing new technologies under rainfed farming conditions in Sri Lanka : a case study
Timing of cultural practices and income distribution throughout
the year were considered to be the key factors in the success of rainfed
farming. It was felt that new technologies for labour saving at peak
periods and a crop that could be harvested during the off period are useful
approaches to improving the production capacity of rainfed farms. This
study aims to assess the economic benefits of new technologies (NTs)
developed for rainfed farms in a range of practical farm situations. A
case study approach was employed in exploring this situation. Two sample
farmers were selected from a rainfed project conducted in the dry zone of
Sri Lanka.
Whole farm planning based on Linear Programming (LP) was employed.
Essentially, it looks at the farm-household as a whole entity with a common
resource base, interrelated with the various activities of the farmer.
This was demonstrated using only the historical technologies. The optimal
plan generated specified a combination of alternative enterprises subject
to a restricted resource base.
The impact of introducing NTs was assessed by comparing the
previous solution which employs only historical technologies with the new
situation. That is, new technologies to be evaluated are included in the
farmers' options along with the historical technologies. These new
technologies include mechanical weeding, chemical weeding and a dwarf variety
of castor
Synthesis of Nitrogenated Heterocycles by Asymmetric Transfer Hydrogenation of N-(tert-Butylsulfinyl)haloimines
Highly optically enriched, protected, nitrogenated heterocycles with different ring sizes have been synthesized by a very efficient methodology consisting of the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)haloimines followed by treatment with a base to promote an intramolecular nucleophilic substitution process. N-Protected aziridines, pyrrolidines, piperidines, and azepanes bearing aromatic, heteroaromatic, and aliphatic substituents have been obtained in very high yields and diastereomeric ratios up to >99:1. The free heterocycles can be easily obtained by a simple and mild desulfinylation procedure. Both enantiomers of the free heterocycles can be prepared with the same good results by changing the absolute configuration of the sulfur atom of the sulfinyl group.This work was generously supported by the Spanish Ministerio de Ciencia e Innovación (MICINN; grant no. CONSOLIDER INGENIO 2010, CSD2007-00006, CTQ2007-65218 and CTQ2011-24151) and the Generalitat Valenciana (PROMETEO/2009/039 and FEDER). O.P. thanks the Spanish Ministerio de Educación for a predoctoral fellowship (grant no. AP-2008-00989)
First report on \u3cem\u3eHottentotta tamulus\u3c/em\u3e (Scorpiones: Buthidae) from Sri Lanka, and its medical importance
A scorpion species proved to be lethal to humans was recently recorded from Jaffna Peninsula (9°40\u270\u27\u27N 80°0\u270\u27\u27E, mean annual temperature 26.2°C), in the northern dry zone of Sri Lanka. This species is morphologically different from all other known scorpions in Sri Lanka. The species was identified as Hottentotta tamulus (Scorpiones: Buthidae), which is commonly found in Maharashtra, India, the closest mainland to Sri Lanka. Small children and housewives were most of the victims. Soon after sting, the patient develops intense pain at the site of sting followed by numbed sensation. Dominant clinical effects include excessive sweating, agitation and palpitation. Blood pressure of the victim goes up, and if not promptly treated leads to acute heart failure. There is a high risk of spreading of this species to the rest of the country due to transport of goods and sand from the area
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