546 research outputs found

    Substituent Effect on Pyridine Efficacy as a Chelating Stabilizer

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    Owing to the growing interest and unique properties of pyridines as bases, effects of substitution and substituent modification on electron density enrichment of the pyridyl nitrogen, and thus the effectiveness of pyridine as metal ion-stabilizers will be introduced in this chapter. Pyridines of the structure C5(S)nH5-nN (S = substituent) that have been intensively studied theoretically were selected as examples to prove the concept of this chapter. Computational results in the reviewed reports showed that: substitution and substituent modification significantly affect the electronic enrichment of nitrogen atom of the pyridine. The conclusions extracted from the covered investigations were employed to promote pyridines to act as efficient stabilizers for the coordinated metal ions. In coordination chemistry, these kinds of coordinated complexes are highly demanded in the field of chemosensation

    Can raisins ameliorate the hypercholesterolaemia-induced cardiac affection?

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    Raisins were investigated for their protective role on cardiac muscle both biochemically and histopathologically in high cholesterol diet (HCD)-fed rats. Wister male rats were randomly divided into four groups (n = 10): control, raisin-fed, HCD-fed and HCD-raisin fed group. Animals were anaesthetized after 13 weeks. Hearts were dissected and processed for histopathological examination. Raisins administration with HCD significantly decreased the animals’ blood glucose, insulin, cholesterol, triglycerides, and low density lipoprotein levels; while increased their high density lipoprotein levels compared with rats fed HCD alone. They also decreased cardiomyocytes’ degeneration, cellular infiltration, haemorrhages and blood vessels affection. Raisins reduced fibrosis by decreasing the immuno-expression of alpha smooth muscle actin marker, whereas they significantly increased the immuno-expression of endothelial nitric oxide synthase. Raisins showed a cardioprotective effect and were able to alleviate the biochemical and the histopathological changes induced by the HCD. Consumption of raisins or their pharmaceutical product should be recommended specially for those eating a high-fat diet

    Variations of the abductor pollicis longus tendon: an anatomic study

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    This study was performed to investigate the variations, dimensions and attachment of the abductor pollicis longus (APL) tendon. Fifty upper limbs of adult cadavers were dissected in the Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia. Variations of APL tendon and its way of insertion were observed;its length, width and thickness were also measured and statistically analysed. Nosingle-tendon-APL was found in all the examined upper limbs. The APL exhibited 2–6 tendons in all the cases. Tendons of APL were classified into medial and lateral. The lateral was considered as the main APL tendon, which was inserted into thebase of the first metacarpal bone. The medial tendons were regarded as accessory slips and were inserted most commonly into the base of the first metacarpalbone; 80% on its anterolateral surface vs. 20% on the lateral one. The rest of themedial slips extended to trapezium, abductor pollicis brevis, thenar fascia, capsuleof first carpometacarpal joint and opponens pollicis, with a frequency of 80%,60%, 40%, 30% and 20%, respectively. Transverse tendinous fibres were noted connecting the various slips of the APL tendons. No significant difference was recorded between the length of the main APL tendon and its accessory tendons, however, a highly significant difference was found between their thicknesses aswell as their widths. Thus it is verified that the lateral tendon of APL is the main,whereas the medial tendons are accessory. The observations regarding dimensions and variations of the APL and their accessory tendons may prove useful tosurgeons as a source of grafting material

    Anatomical variations of the hand extensors

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    This study was performed to investigate the anatomy and variations of the humanextensor tendons of the fingers and their intertendinous connections. Ninetyfive upper limbs of adult cadavers were dissected. The variations in the extensortendons of the fingers, both proximal and distal to the extensor retinaculum, andtheir mode of insertion were observed. Also, the intertendinous connections wereexplored and the obtained data were analysed. The extensor pollicis longus andbrevis tendons were found to be single, doubled or, rarely, absent. Their insertioncould be traced to either the proximal phalanx, or through the extensor expansionto both phalanges, or rarely to the distal phalanx of thumb. The extensor indicishad a single tendon in all specimens. In the majority of specimens, extensor digitorumhad no independent slip to the little finger; it gave off a single tendonto the index, double tendons to the middle finger and triple tendons to the ringfinger. Extensor digiti minimi muscle often had double or triple tendons distal tothe extensor retinaculum. Three types of juncturae tendinum (JT) were identifiedbetween the tendons of extensor digitorum in the 2nd, 3rd and 4th intermetacarpalspaces (IMS) of hands. Types 1 and 2 JT were seen in the three IMS. Type 3 JTwas the most frequently identified of all juncturae and was always absent in the2nd IMS. The percentages of the present data were compared with other researchers’data

    Existence and multiplicity for elliptic problems with quadratic growth in the gradient

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    We show that a class of divergence-form elliptic problems with quadratic growth in the gradient and non-coercive zero order terms are solvable, under essentially optimal hypotheses on the coefficients in the equation. In addition, we prove that the solutions are in general not unique. The case where the zero order term has the opposite sign was already intensively studied and the uniqueness is the rule.Comment: To appear in Comm. PD

    Nonverbal behavior during standardized interviews in patients with schizophrenia spectrum disorders

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    Several studies have consistently shown that patients with schizophrenia or schizophrenia spectrum disorders (SSD) can be distinguished from normal controls on the basis of their nonverbal behavior during standardized interviews, with considerable interactions between negative symptoms and poor facial expressivity. However, most studies have examined unmedicated patients, and gender of both interviewer and interviewee has not been taken into account. In this study we assessed the nonverbal behavior of male and female patients with SSD who were receiving second-generation antipsychotic medication (SGA) using the Ethological Coding System for Interviews (Troisi, 1998). In addition, we used a novel 5-factor model of the Positive and Negative Symptom Scale (PANSS, van der Gaag et al., 2006) to correlate nonverbal behavior with standard psychopathology ratings. Our findings strongly resembled results of previous studies into nonverbal behavior of patients with SSD, despite differences in cultural backgrounds and gender of the interviewer. Negative symptoms were inversely correlated with several of the nonverbal behavioral dimensions. Medication dose did not correlate with any one of the behavioral or psychopathological measures. Patients with SSD make less use of their nonverbal behavioral repertoire compared with controls, independent of antipsychotic treatment. Culture-specific nonverbal expressivity seems to play an additional (minor) role in distinguishing patients from healthy controls

    Synthesis of some quinoline thiosemicarbazone derivatives of potential antimicrobial activity

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    5-Acetyl (or 5-benzoyl)-8-hydroxyquinoline-4-substituted thiosemi-carbazones (IIa-m, IIIa-m respectively) have been prepared via the condensation of . The thiosemicarbazones (IIa-l, IIIa-f) were subjected to cyclization into the corresponding thiazolidinones (IVa-l, Va-f) by the reaction with ethyl bromoacetate in the presence of anhydrous sodium acetate. The structures of the thiosemicarbazones as well as the corresponding thiazolidinones were assigned based on both elemental and spectroscopic evidences. The prepared compounds were also evaluated for antibacterial and antifungal activities

    Effort estimation of FLOSS projects: A study of the Linux kernel

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    This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2011 SpringerEmpirical research on Free/Libre/Open Source Software (FLOSS) has shown that developers tend to cluster around two main roles: “core” contributors differ from “peripheral” developers in terms of a larger number of responsibilities and a higher productivity pattern. A further, cross-cutting characterization of developers could be achieved by associating developers with “time slots”, and different patterns of activity and effort could be associated to such slots. Such analysis, if replicated, could be used not only to compare different FLOSS communities, and to evaluate their stability and maturity, but also to determine within projects, how the effort is distributed in a given period, and to estimate future needs with respect to key points in the software life-cycle (e.g., major releases). This study analyses the activity patterns within the Linux kernel project, at first focusing on the overall distribution of effort and activity within weeks and days; then, dividing each day into three 8-hour time slots, and focusing on effort and activity around major releases. Such analyses have the objective of evaluating effort, productivity and types of activity globally and around major releases. They enable a comparison of these releases and patterns of effort and activities with traditional software products and processes, and in turn, the identification of company-driven projects (i.e., working mainly during office hours) among FLOSS endeavors. The results of this research show that, overall, the effort within the Linux kernel community is constant (albeit at different levels) throughout the week, signalling the need of updated estimation models, different from those used in traditional 9am–5pm, Monday to Friday commercial companies. It also becomes evident that the activity before a release is vastly different from after a release, and that the changes show an increase in code complexity in specific time slots (notably in the late night hours), which will later require additional maintenance efforts

    A Hybrid Model for Dynamic Simulation of Custom Software Projects in a Multiproject Environment

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    This paper describes SimHiProS, a hybrid simulation model of software production. The goal is to gain insight on the dynamics induced by resource sharing in multiproject management. In order to achieve it the hierarchy of decisions in a multiproject organization is modeled and some resource allocation methods based on algorithms from the OR/AI domain are used. Other critical issues such as the hybrid nature of software production and the effects of measurement and control are also incorporated in the model. Some first results are presented.Ministerio de Ciencia e InnovaciĂłn TIN2004-06689-C03-03Ministerio de Ciencia e InnovaciĂłn TIN2007-67843-C06-0

    Bio-Inspired Multi-Layer Spiking Neural Network Extracts Discriminative Features from Speech Signals

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    Spiking neural networks (SNNs) enable power-efficient implementations due to their sparse, spike-based coding scheme. This paper develops a bio-inspired SNN that uses unsupervised learning to extract discriminative features from speech signals, which can subsequently be used in a classifier. The architecture consists of a spiking convolutional/pooling layer followed by a fully connected spiking layer for feature discovery. The convolutional layer of leaky, integrate-and-fire (LIF) neurons represents primary acoustic features. The fully connected layer is equipped with a probabilistic spike-timing-dependent plasticity learning rule. This layer represents the discriminative features through probabilistic, LIF neurons. To assess the discriminative power of the learned features, they are used in a hidden Markov model (HMM) for spoken digit recognition. The experimental results show performance above 96% that compares favorably with popular statistical feature extraction methods. Our results provide a novel demonstration of unsupervised feature acquisition in an SNN
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