918 research outputs found
Synthesis and structure elucidation of novel pyrazolyl-2-pyrazolines obtained by the reaction of 3-(3-aryl-3-oxopropenyl)chromen-4-ones with phenylhydrazine
Novel 3-aryl-5-{4-[5-(2-hydroxyphenyl)-1-phenylpyrazolyl]}-2-pyrazolines 2a-g have been prepared by the treatment of 3-(3-aryl-3-oxopropenyl)chromen-4-ones 1a-g with phenylhydrazine in refluxing acetic acid. NMR studies on deuteriochloroform solutions of pyrazolyl-2-pyrazolines 2a-g at different temperatures showed that at room temperature a mixture of diastereomers are present. This diastereoselectivity arises from the combination of the pyrazoline C-4 stereocenter and two planar chiral subunits due to internal steric hindrance. The energy barriers of this steric hindrance were overcome in DMSO-d6 solutions at 60oC. The acetylation of some pyrazolyl-2-pyrazoline derivativess 2a-c,e helped to confirm the presence of the referred mixture of diastereomers
Dimethyldioxirane oxidation of exocyclic (E,E)-cinnamylideneketones
http://apps.isiknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=11&SID=X22NMCKHdF5lcLIJG6o&page=1&doc=1&colname=WOSExocyclic (E,E)-cinnamylideneketones were oxidized by an excess of isolated dimethyldioxirane (DMDO, in acetone
solution) at room temperature, providing diastereomeric mixtures of the α,β:γ,δ-diepoxides. In the case of derivatives
bearing an ortho-nitrocinnamylidene moiety, α,β-monoepoxides were also isolated as minor products. The structures of
all new compounds and the stereochemistry of the monoepoxides and diepoxide diastereomers were established by NMR
studies
Determinants of Loan Repayment Performance Among Women Self Help Groups in Bayelsa State, Nigeria
This paper investigated the determinants of loan repayment performance among women self-help groups in Bayelsa State, Nigeria. A structured questionnaire was used to gather information from one hundred and twelve (112) women farmers from eight communities within the States, using the multistage sampling technique. The study revealed that credit was available for agricultural production, processing and petty trading among women farmers. The mean amount of loan disbursed to farmers was N18,147.3 while the mean amount of N15,000 was repaid. Loan repayment percentage was determined to be 83.73% while percentage default was 17.27%. The estimated regression model indicated that women as household heads (X2), interest rate (X3) and household size (X4), negatively and significantly affected the loan repayment performance of women farmers while price stability of farm proceeds (X5) and commitment to self help groups (X6), positively and significantly affected the loan repayment of women farmers in self help groups in the area. It was therefore recommended that more self help credit/saving groups be established in the state and that financial institutions within the state should form a linkage with this groups for efficient loan scheme
Reefs under siege-the rise, putative drivers and consequences of benthic cyanobacterial mats.
A randomized trial of glutamine and antioxidants in critically ill patients.
BACKGROUND: Critically ill patients have considerable oxidative stress. Glutamine and antioxidant supplementation may offer therapeutic benefit, although current data are conflicting.
METHODS: In this blinded 2-by-2 factorial trial, we randomly assigned 1223 critically ill adults in 40 intensive care units (ICUs) in Canada, the United States, and Europe who had multiorgan failure and were receiving mechanical ventilation to receive supplements of glutamine, antioxidants, both, or placebo. Supplements were started within 24 hours after admission to the ICU and were provided both intravenously and enterally. The primary outcome was 28-day mortality. Because of the interim-analysis plan, a P value of less than 0.044 at the final analysis was considered to indicate statistical significance.
RESULTS: There was a trend toward increased mortality at 28 days among patients who received glutamine as compared with those who did not receive glutamine (32.4% vs. 27.2%; adjusted odds ratio, 1.28; 95% confidence interval [CI], 1.00 to 1.64; P=0.05). In-hospital mortality and mortality at 6 months were significantly higher among those who received glutamine than among those who did not. Glutamine had no effect on rates of organ failure or infectious complications. Antioxidants had no effect on 28-day mortality (30.8%, vs. 28.8% with no antioxidants; adjusted odds ratio, 1.09; 95% CI, 0.86 to 1.40; P=0.48) or any other secondary end point. There were no differences among the groups with respect to serious adverse events (P=0.83).
CONCLUSIONS: Early provision of glutamine or antioxidants did not improve clinical outcomes, and glutamine was associated with an increase in mortality among critically ill patients with multiorgan failure. (Funded by the Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00133978.)
Sustainability-driven decision-making model: case study of fiber-reinforced concrete foundation piles
Currently, foundation piles for inhabited areas are often constructed using a continuous flight auger, which is a cost- and time-efficient technology that does not require stabilization of the borehole wall; the steel bar reinforcement is embedded after the concrete has been poured. However, this reinforcement operation can lead to severe construction and structural issues. Thus, several improvements to this technology have been proposed since its first application in the 20th century, such as the use of more fluid concretes. Nevertheless, steel and polymers are emerging as a potential replacement for steel bars in concrete reinforcement for several types of structures and building components, with identified and quantified benefits from a sustainability perspective. Accordingly, this paper proposes and validates a multicriteria decision-making approach designed with multidisciplinary experts within the construction field to assess the sustainability index of concrete pile foundations. The results of a case study enable us to conclude that polymeric fiber-reinforced concrete piles are the most sustainable due to their cost–structural efficiency ratio, high durability, and minimal risks during construction. Steel fiber-reinforced concrete alternatives were also found to be more sustainable than traditional reinforced concrete. Nonetheless, these results are unrepresentative of the current practice as direct costs were found to be the main driver in the decision-making processes, while other costs and both environmental and social indicators are disregarded. This justifies the urgency to provide sustainability-driven decision-making approaches capable of objectively quantifying the satisfaction degree of economic, environmental, and social indicators involved in the analysis
A three-layer MRI-based head phantom for experimental validation of tES simulations
Transcranial electric stimulation (tES) is being investigated for the relief of seizures in medically refractory epilepsy patients. In a quest to optimize the electrode placement and current for improvement of the outcome, we are investigating the exploitation of the pre-stimulation planning using finite element simulations based on individual anatomy from MRI [RM1] scans. A crucial step is validating the stimulation modeling accuracy, but commercial setups for validation do not exist.Hereto, we developed a three-layer head phantom, consisting of skin, skull, and brain tissue, that captures the crucial anatomical features and provides a convenient way of verifying the induced electric fields. It also enables systematic characterization of the uncertainties and variations in conductivity and anatomy. Experiments on the three-layer phantom bridge the gap between simulations and clinical practice since they also allow for using clinical hardware and electrodes.The developed phantom consists of an agar and salt brain layer, a graphite-doped polyurethane skull, and a skin layer made from agar gel with a different conductivity. In this way the solid skull separates the two gel layers, preventing possible ion drift over the layers. The anatomy is based on the ICBM 152 linear model, an average of 152 MRI scans, which enables us to intuitively link measurements and simulations. To perform the systematic characterization experiments, hardware and software were designed in-house. This allows for stimulations and measurements on the phantom in a cheap and modular way. The designed hardware consists of a PID-controlled tES stimulator, which can deliver 4 mA with a frequency up to 100 Hz, and a four-channel differential sensing board based on the OpenBCI Ganglion board.A realistic and modular phantom expands the possibilities of preclinical tES research by providing a tool to validate electric field simulations as well as experiment with clinical hardware and anatomical variations
Correlation between periodontal disease management and metabolic control of type 2 diabetes mellitus: a systematic literature review
Background: Diabetes and periodontal disease share common features in terms of inflammatory responses. Current
scientific evidence suggests that treatment of periodontal disease might contribute to glycemic control. The
objective of the study is a review of the last three years.
Material and Methods: A literature search was performed in the MEDLINE (PubMed), Cochrane, and Scopus databases,
for articles published between 01-01-2013 and 30-06-2015, applying the key terms “periodontal disease”
AND “diabetes mellitus”. The review analyzed clinical trials of humans published in English and Spanish.
Results: Thirteen clinical trials were reviewed, representing a total of 1,912 patients. Three of them had samples of
40 patients, representing a total
of 1,804. Only one article achieved a Jadad score of five. Seven articles (998 patients, 52.3% total), presented a statistically
significant decrease in HbA1c (p<0.05) as a result of periodontal treatment. In the six remaining articles
(representing 914 patients, 47.8% of the total), the decrease in HbA1c was not significant. Patient follow-up varied
between 3 to 12 months. In three articles, the follow-up was of 3, 4, and 9 months, in two 6 and 12 months.
Conclusions: The majority of clinical trials showed that radicular curettage and smoothing, whether associated
with antibiotics or not, can improve periodontal conditions in patients with diabetes mellitus. However, few studies
suggest that this periodontal treatment improves metabolic control. However, there is no clear evidence of a
relation between periodontal treatment and improved glycemic control in patients with type 2 diabetes mellitu
The low energy limit of the non-commutative Wess-Zumino model
The non-commutative Wess-Zumino model is used as a prototype for studying the
low energy behaviour of a renormalizable non-commutative field theory. We start
by deriving the potential mediating the fermion-fermion and boson-boson
interactions in the non-relativistic regime. The quantum counterparts of these
potentials are afflicted by irdering ambiguities but we show that there exists
an ordering prescription which makes them hermitean. For space/space
noncommutativity it turns out that Majorana fermions may be pictured as rods
oriented perpendicularly to the direction of motion showing a lack of
localituy, while bosons remain insensitive to the effects of noncommutativity.
For time/space noncommutativity bosopns and fermions can be regarded as rods
oriented along the direction of motion. For both cases of noncommutativity the
scattering state described scattered waves, with at least one wave having
negative time delay signalizing the underlying nonlocality. The superfield
formulation of the model is used to compute the corresponding effective action
in the one- and two-loop approximations. In the case of time/space
noncommutativity, unitarity is violated in the relativistic regime. However,
this does not preclude the existence of the unitary low energy limit.Comment: 14 pages, 2 figures, minor correction
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