5,831 research outputs found

    A tale of three kingdoms: Members of the Phylum Nematoda independently acquired the detoxifying enzyme cyanase through horizontal gene transfer from plants and bacteria

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    Horizontal gene transfer (HGT) has played an important role in the evolution of nematodes. Among candidate genes, cyanase, which is typically found only in plants, bacteria and fungi, is present in more than 35 members of the Phylum Nematoda, but absent from free-living and clade V organisms. Phylogenetic analyses showed that the cyanases of clade I organisms Trichinella spp., Trichuris spp. and Soboliphyme baturini (Subclass: Dorylaimia) represent a well-supported monophyletic clade with plant cyanases. In contrast, all cyanases found within the Subclass Chromadoria which encompasses filarioids, ascaridoids and strongyloids are homologous to those of bacteria. Western blots exhibited typical multimeric forms of the native molecule in protein extracts of Trichinella spiralis muscle larvae, where immunohisto- chemical staining localized the protein to the worm hypodermis and underlying muscle. Recombinant Trichinella cyanase was bioactive where gene transcription profiles support functional activity in vivo. Results suggest that: (1) independent HGT in parasitic nematodes originated from different Kingdoms; (2) cyanase acquired an active role in the biology of extant Trichinella; (3) acquisition occurred more than 400 million years ago (MYA), prior to the divergence of the Trichinellida and Dioctophymatida, and (4) early, free-living ances- tors of the genus Trichinella had an association with terrestrial plants

    Decision Factors for the Adoption and Continued Use of Online Direct Sales Channels among SMEs

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    Although more and more small and medium-sized enterprises (SMEs) use the Internet for business purposes, few of them have adopted the Internet as an online direct sales channel (ODSC). Among those that do use the ODSC, some end up abandoning it after adoption. This study explores a few critical factors underlying the initial adoption and continued use of online direct sales channels among SMEs. Synthesizing existing works, we construct an innovation adoption decision factors classification framework that classifies innovation decision factors into three dimensions: decision entity factors, decision object factors, and context factors. We then operationalize these factors in the context of SMEs’ initial adoption and post-adoption continued use of online direct sales channels. We conduct a survey study on SMEs within the United States. The results demonstrate that an SME’s initial adoption and post-adoption continued use of an ODSC involve different sets of decision factors. Furthermore, results demonstrate a learning effect within adopting firms that implies they perceive the relative advantage of ODSC differently in comparison to pre-adopters

    Acute and Subacute Toxic Study of Aqueous Leaf Extract of Combretum Molle

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    Purpose: The purpose of the present study was to evaluate the acute and subacute toxicity of the aqueous leaf extract of Combretum molle.Methods: The acute toxicity of the extract was evaluated in rats. The animals were orally administered with doses ranging from 2000 to 8000 mg/kg and observed continuously for the first 4 h, then hourly for the next 24 h, and finally, 6-hourly for 72 h. Control animals received orally normal saline. The rats were observed carefully for mortality, pain as well as respiratory movements. For subacute toxicity, 6 groups of 6 rats (3 male and 3 female) each received intraperitoneally, normal saline (control), 400, 600, 800, 1000 and 1200 mg/kg of the extract, respectively, thrice daily for 15 days. At the end of the treatment period, the animals were sacrificed and their organs (liver, heart and kidney) removed for macroscopic examination.Results: For the acute toxicit test, no death and signs of poisoning were observed in the treated groups. In the subacute tstudy, LD50 in the rats after intraperitoneal administration was 700 mg/kg (456 - 896, 95 % confidence interval). The clinical signs of poisoning (motor difficulties, decreased respiratory rate, and tremor preceding death) were observed, suggesting overt toxicity throughout the neuromuscular system. However, histological examination of vital organs showed normal architecture suggesting no morphological abnormalities in the heart, kidney and liver.Conclusion: The results show that the aqueous leaf extract of C. molle is moderately toxic when given intraperitoneally.Keywords: Combretum molle, Acute/subacute toxicity, Histopathology, Rat

    Evaluation agronomique de variĂ©tĂ©s de canne Ă  sucre en dĂ©but de campagne de rĂ©colte Ă  FerkĂ© au Nord de la CĂŽte d’Ivoire : vers un allĂšgement du schĂ©ma de sĂ©lection

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    Dans le but de contribuer Ă  l’allĂšgement du schĂ©ma de sĂ©lection de la canne Ă  sucre, 16 variĂ©tĂ©s ont Ă©tĂ© Ă©valuĂ©es, sur la base du rendement en sucre extractible, de la tolĂ©rance au charbon (U. scitaminea), Ă  l’échaudure des feuilles (maladies endĂ©miques) et au foreur de tiges (E. saccharina), dans 4 essais, conduits sur 5 ans, en dĂ©but de saison de rĂ©colte Ă  Sucaf-FerkĂ© 2 (nord de la CĂŽte d’Ivoire). Les variĂ©tĂ©s commerciales SP701143, SP711406, MEX73523, N19, R575, SP75184 et SP791230 ont prĂ©sentĂ©, respectivement, des TSE/ha de 12,2 ; 15,3 ; 11,6 ; 11,7 ; 10,6 ; 11,5 et 12,1 significativement supĂ©rieures Ă  celles de NCo376 (variĂ©tĂ© la plus cultivĂ©e jusqu’en 2008). Par ailleurs, celles-ci ont Ă©tĂ© moins sensibles au charbon et au foreur de tiges que NCo376 (taux de charbon < 5000 fouets/ha et ENA % < 3 %). Les variĂ©tĂ©s commerciales se sont avĂ©rĂ©es plus adaptĂ©es aux conditions de culture du site que les prĂ©sĂ©lectionnĂ©es, avec des taux d’adaptation de 33 %, 100 %, 67 % et 75 %. L’étude suggĂšre en outre, la possibilitĂ© de rĂ©duire la 2e Ă©tape de sĂ©lection de 2 ans et de conduire le criblage en une seule Ă©tape de 3 ans. Ce qui ramĂšnerait la durĂ©e du cycle de sĂ©lection Ă  6 ans, contre 11, voire 15 ans auparavant.Mots clĂ©s : VariĂ©tĂ©s de canne Ă  sucre, adaptation, charbon, foreur, CĂŽte d’Ivoir

    Towards Understanding Hierarchical Learning: Benefits of Neural Representations

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    Deep neural networks can empirically perform efficient hierarchical learning, in which the layers learn useful representations of the data. However, how they make use of the intermediate representations are not explained by recent theories that relate them to "shallow learners" such as kernels. In this work, we demonstrate that intermediate neural representations add more flexibility to neural networks and can be advantageous over raw inputs. We consider a fixed, randomly initialized neural network as a representation function fed into another trainable network. When the trainable network is the quadratic Taylor model of a wide two-layer network, we show that neural representation can achieve improved sample complexities compared with the raw input: For learning a low-rank degree-pp polynomial (p≄4p \geq 4) in dd dimension, neural representation requires only O~(d⌈p/2⌉)\tilde{O}(d^{\lceil p/2 \rceil}) samples, while the best-known sample complexity upper bound for the raw input is O~(dp−1)\tilde{O}(d^{p-1}). We contrast our result with a lower bound showing that neural representations do not improve over the raw input (in the infinite width limit), when the trainable network is instead a neural tangent kernel. Our results characterize when neural representations are beneficial, and may provide a new perspective on why depth is important in deep learning.Comment: 41 pages, published in NeurIPS 202

    Prenatal diagnosis of total and partial anomalous pulmonary venous connection: multicenter cohort study and meta-analysis

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    Objectives: The aims of this study were to review systematically literature on and describe the sonographic features and associated anomalies of total (TAPVC) and partial (PAPVC) anomalous pulmonary venous connection and scimitar syndrome (SS). Methods: A retrospective cohort study was carried out of cases of TAPVC, PAPVC and SS that underwent comprehensive ultrasound examination, seen over a 20-year period at two tertiary referral centers. Assessed variables included TAPVC subtype, gestational age at diagnosis, area behind the left atrium, ventricular disproportion, vertical vein, pulmonary venous obstruction, mode of diagnosis, association with cardiac and extracardiac conditions, and pregnancy and fetoneonatal outcomes. The outcome was considered favorable if the individual was alive and well (no functional impairment from surgery or cardiac or extracardiac conditions). Cases associated with right isomerism were excluded from the analysis, as TAPVC in these cases was only one of several major cardiac anomalies affecting sonographic signs. A systematic review was performed in order to obtain a synthesis of characteristics associated with TAPVC, PAPVC and SS. The literature search of PubMed and EMBASE (1970–2016) included reviews, case series and case reports. A meta-analysis was conducted only for TAPVC. Random-effects models were used to obtain pooled estimates of the frequencies of clinical characteristics and sonographic features. Results: For TAPVC, a total of 15 studies involving 71 patients (including 13 from the current cohort study) were included in the systematic review and meta-analysis. The pooled estimate for the association of TAPVC with congenital heart disease was 28.3% (95% CI, 18.1–41.3%) and with extracardiac anomalies it was 18.5% (95% CI, 10.5–30.6%). Of TAPVC cases, obstructed venous return was observed in 34.1% (95% CI, 22.7–47.7%), a favorable outcome in 43.8% (95% CI, 24.0–65.8%), ventricular disproportion in 59.2% (95% CI, 45.1–72.0%), increased area behind the left atrium in 58.1% (95% CI, 41.1–73.5%) and a vertical vein in 59.3% (95% CI, 41.1–75.3%). Diagnosis was established by using color or power Doppler in 84.9% (95% CI, 67.3–93.9%) of cases. For SS, there were only three studies describing eight cases, to which the current study added another five. Ventricular disproportion was present in three out of nine SS cases for which data were available, but for two of these, there was a concurrent heart anomaly. Color Doppler was used for all SS diagnoses, and four-dimensional echocardiography was useful in two out of six cases in which it was used. Outcome for SS cases was generally good. For PAPVC, there were only five studies describing five cases, to which the current study added another two. Major cardiac anomalies were associated in four out of seven of these cases, and extracardiac anomalies in three out of six cases for which data were available. Conclusions: TAPVC can be associated with other cardiac and extracardiac anomalies in a significant percentage of cases. Leading sonographic signs are ventricular disproportion, increased area behind the left atrium and the finding of a vertical vein. Color/power Doppler is the key mode for diagnosis of TAPVC. Obstructed venous return can be expected in roughly one-third of cases of TAPVC and outcome is favorable in less than half of cases. Data for SS and PAPVC are too few to synthesize. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd

    Caracterisation moleculaire et selection de varietes de manioc resistantes contre Xanthomonas axonopodis PV. Manihotis en Cote d’Ivoire

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    La bactĂ©riose du manioc causĂ©e par Xanthomonas axonopodis pv. manihotis cause de dommages aux cultures de manioc en CĂŽte d’Ivoire. En vue d’avoir une meilleure connaissance de l’agent pathogĂšne, 800 isolats ont Ă©tĂ© collectĂ©s des fragments de feuilles et de tiges de manioc malades dans six des sept zones agroĂ©cologiques (ZAE). Les colonies bactĂ©riennes de chaque isolat montrant les caractĂ©ristiques morphologiques typiques Xanthomonas axonopodis pv. manihotis ont Ă©tĂ© soumises Ă  une analyse molĂ©culaire. En se basant sur le dĂ©nombrement des feuilles attaquĂ©es par la maladie, la sensibilitĂ© de huit variĂ©tĂ©s de manioc a Ă©tĂ© Ă©valuĂ©e dans les conditions d’infestation naturelle Ă  FerkessĂ©dougou. Les rĂ©sultats ont montrĂ© aprĂšs 48 heures d’incubation, des colonies de caractĂ©ristiques morphologiques, blanc-ivoire, lisses, brillantes, convexes, avec des contours rĂ©guliers, non puantes et d’aspect visqueux. L’amplification par PCR de l’ADN, a montrĂ© un profil Ă  une seule bande d’une taille d’environ 900 pb caractĂ©ristique de Xanthomonas axonopodis pv. manihotis. Des huit variĂ©tĂ©s testĂ©es, seules les variĂ©tĂ©s amĂ©liorĂ©es « Bocou 2 » et « Yavo » ont Ă©tĂ© les moins attaquĂ©es. Xanthomonas axonopodis pv. manihotis est bien sĂ»r l’agent causal des taches, brĂ»lures et dieback observĂ©es sur les variĂ©tĂ©s de manioc en CĂŽte d’Ivoire. Donc, les variĂ©tĂ©s « Bocou 2 » et « Yavo » peuvent ĂȘtre recommandĂ©es aux producteurs des zones oĂč la bactĂ©riose vasculaire du manioc sĂ©vit plus.Mots clĂ©s : Manioc, Xanthomonas axonopodis pv. manihotis, caractĂ©risation molĂ©culaire, rĂ©sistance variĂ©tal

    Anti-inflammatory recombinant TSG-6 stabilizes the progression of focal retinal degeneration in a murine model

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    <p>Abstract</p> <p>Background</p> <p>Inflammatory responses are detected in the retina of patients with age-related macular degeneration and <it>Ccl2<sup>-/-</sup>/Cx3cr1<sup>-/- </sup></it>mice on rd8 background,(<it>Ccl2<sup>-/-</sup>/Cx3cr1<sup>-/- </sup></it>mice) a model that develops progressive age-related macular degeneration-like retinal lesions including focal photoreceptor degeneration, abnormal retinal pigment epithelium and A2E accumulation. Tumor necrosis factor-inducible gene 6 protein is an anti-inflammatory protein and has been shown to improve myocardial infarction outcome and chemically injured cornea in mice by suppressing inflammation. In this study, we evaluated the effect of an intravitreous injection of recombinant TSG-6 on the retinal lesions of <it>Ccl2<sup>-/-</sup>/Cx3cr1<sup>-/- </sup></it>mice.</p> <p>Methods</p> <p>Recombinant TSG-6 (400 ng) was administered by intravitreous injection into the right eye of six-week-old C<it>cl2<sup>-/-</sup>/Cx3cr1<sup>-/- </sup></it>mice. Their left eye was injected with phosphate-buffered saline as a control. Funduscopic pictures were taken before injection and sequentially once a month after injection. The mice were killed two months after injection and the ocular histology examined. Retinal A2E, a major component of lipofuscin, was measured by high performance liquid chromatography. The microarray of ocular mRNA of 92 immunological genes was performed. The genes showing differentiated expression in microarray were further compared between the injected right eye and the contralateral (control) eye by [real-time quantitative reverse transcription polymerase chain reaction] qRT-PCR.</p> <p>Results</p> <p>The continuous monitoring of the fundus for two months showed a slower progression or alleviation of retinal lesions in the treated right eyes as compared with the untreated left eyes. Among 23 pairs of eyes, the lesion levels improved in 78.3%, stayed the same in 8.7% and progressed in 13.0%. Histology confirmed the clinical observation. Even though there was no difference in the level of A2E between the treated and the untreated eyes, microarray analysis of 92 immune genes showed that <it>IL-17a </it>was substantially decreased after the treatment. Expression of <it>TNF-α </it>showed a similar pattern to <it>IL-17a</it>. The results were consistent in duplicated arrays and confirmed by qRT-PCR.</p> <p>Conclusions</p> <p>We concluded that intravitreous administration of recombinant TSG-6 might stabilize retinal lesions in <it>Ccl2<sup>-/-</sup>/Cx3cr1<sup>-/- </sup></it>mice on rd8 background. Modulation of ocular immunological gene expressions, especially IL-17a, could be one of the mechanisms.</p
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