39 research outputs found

    Study of the Rheological Behavior of Polyamide 5,6 (PA5,6

    Get PDF
    The rheological behavior of polymer melts and polymer solutions are of great importance in polymer processing, particularly for the analysis and design of processing operations as well as understanding the relationship between structures and properties of the final-products. The objective of the present work was to investigate the rheological behavior of polyamide 5,6  (PA5,6) to obtain information on the effect of temperature on the melt behavior of polyamide 5,6 compared to that of polyamide 6. The rheological properties of polyamide 5,6 (PA5,6) have been studied by means of a Haake  rheometer. The effect of temperature on the storage modulus, loss modulus, and complex viscosity was studied. The obtained results showed that the complex viscosity, storage modulus, and loss modulus of PA5,6 and PA6 decrease with increase of the temperature. It is worth noting that the complex viscosity of PA5,6 remains almost constant showing a Newtonian behavior, on the other hand, the complex viscosity of PA6 slightly decreases with the increase of shear rate exhibits a much nearly Newtonian behavior. Similar behavior was observed for other polyamides such as polyamide 6.6 and polyamide 6.,1

    Detection of Trypanozoon trypanosomes infections on Glossina fuscipes fuscipes (Diptera: Glossinidae) using polymerase chain reaction (PCR) technique in the Blue Nile State, Sudan

    Get PDF
    Tsetse flies transmit many species of trypanosomes in Africa, some of which are human and livestock pathogens of major medical and socio-economic impact. Identification of trypanosomes is essential to assess the disease risk imposed by particular tsetse populations. The present study was carried out to determine the trypanosomal infection rate of tsetse flies (Glossina fuscipes fuscipes) in the Blue Nile State of Sudan. A polymerase chain reaction (PCR) assay was used because of the inherent difficulty of speciating trypanosomal parasites in the fly. Our results show that 4.44% (8/180) of the flies were positive for a Trypanosoma brucei group. Three of eight positive flies reacted with primers for Trypanosoma b. rhodesiense. We did not detect flies infected with T. b. gambiense. Thus, the burden of flies harboring T. b. rhodesiense and T. b. brucei trypanosomes were 1.67 and 2.78%, respectively. This is the first evidence of T. b. rhodesiense in the Yabus District. Thus, HAT case-detection active surveillance and tsetse fly control campaigns should be conducted before the establishment of human settlement, investment of natural resources into agricultural and animal husbandry.Key words: Glossina fuscipes fuscipes, Trypanosoma brucei, T. b. gambiense, T. b. rhodesiense, infection rate, PCR technique, Blue Nile State

    BIM-driven energy simulation and optimization for net-zero tall buildings: sustainable construction management

    Get PDF
    The growing demand for sustainable and energy-efficient buildings, particularly in the context of tall structures, has prompted increased attention to innovative solutions. Despite advancements in Building Information Modelling (BIM) technology, there exists a critical gap in understanding its comprehensive application for achieving net-zero energy consumption in tall buildings, particularly in the Malaysian construction industry. This research addresses this gap by presenting a novel strategy that integrates BIM technology with energy analysis tools for net-zero tall buildings in Malaysia. The aim of the study is to contribute valuable insights to the construction industry, policymakers, and researchers by conducting empirical research, utilizing case studies, validating the proposed framework, advancing sustainable design practices, and supporting the transition towards net-zero energy tall buildings in Malaysia. The methodology involves a three-phase approach, including qualitative analysis, a pilot survey, and a main questionnaire. Exploratory factor analysis (EFA) validates the categorization derived from qualitative interviews, while Partial Least Squares Structural Equation Modelling (PLS-SEM) assesses the convergent and discriminant validity of the measurement model. Hypotheses testing using bootstrapping establishes the significance of correlations between BIM deployment and key factors such as early design integration, enhanced energy efficiency, optimized system integration, predictive performance analysis, and validation of sustainable design. The research findings support the positive associations between BIM deployment and the mentioned factors, providing statistical significance through T-statistics and p-values. The implications of this research extend beyond the Malaysian context, offering valuable insights for architects, engineers, and stakeholders involved in designing and managing sustainable tall buildings. By addressing the identified gaps and leveraging BIM technology effectively, stakeholders can contribute to the construction of net-zero energy structures, aligning with global efforts towards sustainable and energy-efficient building practices

    Panels of chemically-modified heparin polysaccharides and natural heparan sulfate saccharides exhibit differences in binding to Slit and Robo, as well as variation between protein binding and cellular activity.

    Get PDF
    Heparin/ heparan sulfate (HS) glycosaminoglycans are required for Slit-Robo cellular responses. Evidence exists for interactions between each combination of Slit, Robo and heparin/HS and for formation of a ternary complex. Heparin/HS are complex mixtures displaying extensive structural diversity. The relevance of this diversity has been studied to a limited extent using a few select chemically-modified heparins as models of HS diversity. Here we extend these studies by parallel screening of structurally diverse panels of eight chemically-modified heparin polysaccharides and numerous natural HS oligosaccharide chromatographic fractions for binding to both Drosophila Slit and Robo N-terminal domains and for activation of a chick retina axon response to the Slit fragment. Both the polysaccharides and oligosaccharide fractions displayed variability in binding and cellular activity that could not be attributed solely to increasing sulfation, extending evidence for the importance of structural diversity to natural HS as well as model modified heparins. They also displayed differences in their interactions with Slit compared to Robo, with Robo preferring compounds with higher sulfation. Furthermore, the patterns of cellular activity across compounds were different to those for binding to each protein, suggesting that biological outcomes are selectively determined in a subtle manner that does not simply reflect the sum of the separate interactions of heparin/HS with Slit and Robo

    A molecular mechanism for the heparan sulfate dependence of Slit-Robo signaling

    Get PDF
    Slit is a large secreted protein that provides important guidance cues in the developing nervous system and in other organs. Signaling by Slit requires two receptors, Robo transmembrane proteins and heparan sulfate (HS) proteoglycans. How HS controls Slit-Robo signaling is unclear. Here we show that the second leucine-rich repeat domain (D2) of Slit, which mediates binding to Robo receptors, also contains a functionally important binding site for heparin, a highly sulfated variant of HS. Heparin markedly enhances the affinity of the Slit-Robo interaction in a solid-phase binding assay. Analytical gel filtration chromatography demonstrates that Slit D2 associates with a soluble Robo fragment and a heparin-derived oligosaccharide to form a ternary complex. Retinal growth cone collapse triggered by Slit D2 requires cell surface HS or exogenously added heparin. Mutation of conserved basic residues in the C-terminal cap region of Slit D2 reduces heparin binding and abolishes biological activity. We conclude that heparin/HS is an integral component of the minimal Slit-Robo signaling complex and serves to stabilize the relatively weak Slit-Robo interaction

    Using the community-based breeding program (CBBP) model as a collaborative platform to develop the African Goat Improvement Network—Image collection protocol (AGIN-ICP) with mobile technology for data collection and management of livestock phenotypes

    Get PDF
    Introduction: The African Goat Improvement Network Image Collection Protocol (AGIN-ICP) is an accessible, easy to use, low-cost procedure to collect phenotypic data via digital images. The AGIN-ICP collects images to extract several phenotype measures including health status indicators (anemia status, age, and weight), body measurements, shapes, and coat color and pattern, from digital images taken with standard digital cameras or mobile devices. This strategy is to quickly survey, record, assess, analyze, and store these data for use in a wide variety of production and sampling conditions.Methods: The work was accomplished as part of the multinational African Goat Improvement Network (AGIN) collaborative and is presented here as a case study in the AGIN collaboration model and working directly with community-based breeding programs (CBBP). It was iteratively developed and tested over 3 years, in 12 countries with over 12,000 images taken.Results and discussion: The AGIN-ICP development is described, and field implementation and the quality of the resulting images for use in image analysis and phenotypic data extraction are iteratively assessed. Digital body measures were validated using the PreciseEdge Image Segmentation Algorithm (PE-ISA) and software showing strong manual to digital body measure Pearson correlation coefficients of height, length, and girth measures (0.931, 0.943, 0.893) respectively. It is critical to note that while none of the very detailed tasks in the AGIN-ICP described here is difficult, every single one of them is even easier to accidentally omit, and the impact of such a mistake could render a sample image, a sampling day’s images, or even an entire sampling trip’s images difficult or unusable for extracting digital phenotypes. Coupled with tissue sampling and genomic testing, it may be useful in the effort to identify and conserve important animal genetic resources and in CBBP genetic improvement programs by providing reliably measured phenotypes with modest cost. Potential users include farmers, animal husbandry officials, veterinarians, regional government or other public health officials, researchers, and others. Based on these results, a final AGIN-ICP is presented, optimizing the costs, ease, and speed of field implementation of the collection method without compromising the quality of the image data collection

    Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

    Get PDF
    Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely
    corecore