237 research outputs found

    Cutting-Edge Green Polymer/Nanocarbon Nanocomposite for Supercapacitor—State-of-the-Art

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    Supercapacitors have attained a special stance among energy storage devices such as capacitors, batteries, fuel cell, and so forth. In this state-of-the-art overview on green synthesis approaches and green materials for supercapacitors, the cutting-edge green polymer/nanocarbon nanocomposite systems were explored by focusing on the design and related essential features. In this regard, various polymers were reconnoitered including conjugated polymers, thermosetting matrices, and green-cellulose-based matrices. Nanocarbon nanomaterials have also expanded research thoughtfulness for green-technology-based energy storage devices. Consequently, green polymer/nanocarbon nanocomposites have publicized fine electron conduction pathways to promote the charge storage, specific capacitance, energy density, and other essential features of supercapacitors. Future research directions must focus on the design of novel high performance green nanocomposites for energy storage applications

    Polymer/Fullerene Nanocomposite for Optoelectronics—Moving toward Green Technology

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    Optoelectronic devices have been developed using the polymer/fullerene nanocomposite, as focused in this review. The polymer/fullerene nanocomposite shows significant structural, electronics, optical, and useful physical properties in optoelectronics. Non-conducting and conducting polymeric nanocomposites have been applied in optoelectronics, such as light-emitting diodes, solar cells, and sensors. Inclusion of fullerene has further broadened the methodological application of the polymer/fullerene nanocomposite. The polymeric matrices and fullerene may have covalent or physical interactions for charge or electron transportation and superior optical features. Green systems have also been explored in optoelectronic devices; however, due to limited efforts, further design innovations are desirable in green optoelectronics. Nevertheless, the advantages and challenges of the green polymer/fullerene nanocomposite in optoelectronic devices yet need to be explored

    Trends and directions in cloud service selection

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    With the growing popularity of cloud computing the number of cloud service providers and services have significantly increased. Thus selecting the best cloud services becomes a challenging task for prospective cloud users. The process of selecting cloud services involves various factors such as characteristics and models of cloud services, user requirements and knowledge, and service level agreement (SLA), to name a few. This paper investigates into the cloud service selection tools, techniques and models by taking into account the distinguishing characteristics of cloud services. It also reviews and analyses academic research as well as commercial tools in order to identify their strengths and weaknesses in the cloud services selection process. It proposes a framework in order to improve the cloud service selection by taking into account services capabilities, quality attributes, level of user's knowledge and service level agreements. The paper also envisions various directions for future research

    Green-Synthesized Graphene for Supercapacitors—Modern Perspectives

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    Graphene is a unique nanocarbon nanostructure, which has been frequently used to form nanocomposites. Green-synthesized graphene has been focused due to environmentally friendly requirements in recent technological sectors. A very important application of green-synthesized graphene-based nanocomposite has been observed in energy storage devices. This state-of-the-art review highlights design, features, and advanced functions of polymer/green-synthesized graphene nanocomposites and their utility in supercapacitor components. Green graphene-derived nanocomposites brought about numerous revolutions in high-performance supercapacitors. The structural diversity of conjugated polymer and green graphene-based nanocomposites has facilitated the charge transportation/storage capacity, specific capacitance, capacitance retention, cyclability, and durability of supercapacitor electrodes. Moreover, the green method, graphene functionality, dispersion, and matrix–nanofiller interactions have affected supercapacitance properties and performance. Future research on innovative polymer and green graphene-derived nanocomposites may overcome design/performance-related challenging factors for technical usages

    Suspected severe malaria in a sudanese patient affected by sickle cell disease who was treated with hydroxyurea

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    Sickle cell disease (SCD) is the most common genetic disease in sub-Saharan Africa. The signs and symptoms of SCD usually begin in early childhood. Characteristic features of this disorder include anaemia, repeated infections, and periodic episodes of pain. Malaria is one of the infections that can occur in patients with SCD in endemic countries. Many guidelines recommend antimalarial chemoprophylaxis in these patients, although the debate on which drug should be used is still ongoing. Hydroxyurea (HU), which is considered a safe and effective treatment for both children and adults with SCD, seems to affect the incidence and severity of malaria, although these impacts have yet to be fully demonstrated. We report a case of an eight-and-a-half-year-old Sudanese boy with SCD treated with HU admitted for suspected severe malaria who showed a recrudescence after first-line treatment. Although he had undergone splenectomy and thus belonged to a category of patients at high risk for infectious complications, he was not receiving any malaria chemoprophylaxis. This case emphasises the importance of the routine administration of malaria prophylaxis to children with SCD living in endemic areas, even when they are treated with HU, and especially if they are at high risk for infectious complications because they have undergone splenectomy. There is an urgent need for further research to evaluate the most appropriate regimen and its optimal duration

    Fighting the Progress of COVID-19 by Enhancing Immunity: A Review of Traditional Sudanese Natural Products Containing Immune-Boosting Elements

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    The World Health Organization has classified the coronavirus disease outbreak as a worldwide pandemic as a result of the COVID-19 expansion. According to medical professionals, individuals with strong immunity often outlive infections more frequently than those with poor immunity. The COVID-19 pandemic has prompted the need for novel approaches to treating the illness and its symptoms. Natural products from plants are increasingly being seen favorably in comparison to synthetic ones in the fight against diseases. As a result, in order to avoid contracting any unanticipated illnesses, individuals must increase their immunity by eating more dietary supplements and by taking drugs that have immune-boosting properties. This review aimed to give a general overview of some traditional Sudanese foods and drinks that are rich in immune-boosting elements, and accordingly, they could be safely recommended as an adjuvant dietary supplement to improve the immune system\u27s ability to fight such infections as COVID-19. Also, this review aims to bring attention to the fact that immune boosters may be found in natural sources, which will help pharmaceutical companies by taking some of the load off of them. Electronic databases, including Google Scholar, Scopus, and the Web of Science, were searched for relevant material. The selected articles underwent independent eligibility and information extraction reviews. The review focused on certain traditional Sudanese herbs and their derivatives that are rich in immune-stimulating vitamins and minerals and therefore could possibly be recommended as immune-boosting dietary supplements to help fight COVID-19. This review highlights the fact that the pharmaceutical sector, especially community and hospital pharmacists, could play a vital role in supporting the healthcare system by encouraging their communities to add plants and their products that are rich in immune-boosting vitamins and minerals to their diet

    What doesn't kill you makes you stranger: Dipeptidyl peptidase-4 (CD26) proteolysis differentially modulates the activity of many peptide hormones and cytokines generating novel cryptic bioactive ligands

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    Dipeptidyl peptidase 4 (DPP4) is an exopeptidase found either on cell surfaces where it is highly regulated in terms of its expression and surface availability (CD26) or in a free/circulating soluble constitutively available and intrinsically active form. It is responsible for proteolytic cleavage of many peptide substrates. In this review we discuss the idea that DPP4-cleaved peptides are not necessarily inactivated, but rather can possess either a modified receptor selectivity, modified bioactivity, new antagonistic activity, or even a novel activity relative to the intact parent ligand. We examine in detail five different major DPP4 substrates: glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), peptide tyrosine-tyrosine (PYY), and neuropeptide Y (NPY), and stromal derived factor 1 (SDF-1 aka CXCL12). We note that discussion of the cleaved forms of these five peptides are underrepresented in the research literature, and are both poorly investigated and poorly understood, representing a serious research literature gap. We believe they are understudied and misinterpreted as inactive due to several factors. This includes lack of accurate and specific quantification methods, sample collection techniques that are inherently inaccurate and inappropriate, and a general perception that DPP4 cleavage inactivates its ligand substrates. Increasing evidence points towards many DPP4-cleaved ligands having their own bioactivity. For example, GLP-1 can work through a different receptor than GLP-1R, DPP4-cleaved GIP can function as a GIP receptor antagonist at high doses, and DPP4-cleaved PYY, NPY, and CXCL12 can have different receptor selectivity, or can bind novel, previously unrecognized receptors to their intact ligands, resulting in altered signaling and functionality. We believe that more rigorous research in this area could lead to a better understanding of DPP4’s role and the biological importance of the generation of novel cryptic ligands. This will also significantly impact our understanding of the clinical effects and side effects of DPP4-inhibitors as a class of anti-diabetic drugs that potentially have an expanding clinical relevance. This will be specifically relevant in targeting DPP4 substrate ligands involved in a variety of other major clinical acute and chronic injury/disease areas including inflammation, immunology, cardiology, stroke, musculoskeletal disease and injury, as well as cancer biology and tissue maintenance in aging

    Comportamiento de Alfalfa (Medicago Sativa L.) en el Centro Chaqueño Argentino con pastoreo rotativo intensivo y cortes

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    El trabajo tuvo por objetivo evaluar el comportamiento de cultivares de alfalfa en el Chaco (Argentina), bajo pastoreo racional intensivo y cortes. Se evaluaron durante dos años cuatro cultivares comerciales de los grupos 5 (Magnum III), 8 (DK 184 y DK 187) y 9 (DK 192), con latencia intermedia o sin latencia. Se compararon con un testigo local (CUF 101), en una superficie de 7 has. Se realizaron dos cortes de limpieza, a los 20 y 40 días. Luego de un descanso de 80 días comenzó a ser pastoreado. Se complementó con campo natural (21 has). Se usaron novillos Brangus media sangre de 300 kg PV inicial. Los cortes para evaluar rendimiento de MS se realizaron sobre transectas fijas, cortando cuatro repeticiones de 1 m2 en forma manual. El diseño experimental fue bloques completos al azar, en arreglo factorial 2x5 para análisis de rendimiento anual total. La producción estacional se analizó en bloques al azar sin comparar entre años. Se utilizó el test de Tukey para probar diferencias entre medias. La producción total de forraje de los cultivares comerciales superó al testigo en el segundo año. La evolución del número de plantas indicó que a pesar de la disminución, todos los cultivares podrían usarse por 3 o 4 años, excepto el testigo. Los cortes de verano permitieron hacer en promedio 6 rollos/ha en el primer año y 4 en el segundo. La ganancia diaria de peso fue 925 g y 847 g durante el primer y segundo año respectivamente. La utilización de alfalfa para pastoreo y para reservas es una alternativa viable para empresas agrícolas ganaderas en áreas marginales

    Determination of effective parameters on growth and bloom forming of Cochlodinium polykrikoides

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    Harmful algal blooms resulting in red discoloration of coastal waters in the Persian Gulf, Iran were first observed in January 2007. The species responsible for the bloom, which was identified as Cochlodinium polykrikoides, coincided with massive aquatic organisms’ mortalities in the Persian Gulf. In order to provide optimum growth and bloom forming, C. polykrikoides cells were sampled during the bloom conditions in the coastal waters of Persian Gulf. After adaptation in filtered seawater, they isolated by positive phototropism characteristic of this species to light. They were grown in modified media culture at different salinity (30, 32 and 35ppt), temperature (20, 23, 26 and 28ºC) and intensity (35, 70 and 90 µmol m^-2 s^-1) with an initial cell density of 50 cell mL^−1. The results of the present study clearly showed that the highest alga biomass was obtained following culture by using A^2 medium under the 32ppt salinity, 26°C temperature, and under a 11h light:13h dark photoperiod regime at a light intensity of 90 µmol m^-2 s^-1 provided by cool white fluorescent tubes. Mean cell density of C. polykrikoides in a 60 liter tank for ten days reached to 32 × 10^6 cell L^−1. Moreover, individual C. polykrikoides chain with 18 cells was observed for the first time in cultures. Based on the results from the present study, as mentioned above, providing suitable media culture and physical condition (light intensity and temperature), bloom forming of C. polykrikoides start from day 8 to 10 and will be continued until day 24 t0 28. In the other hand, C. polykrikoide cells immediately crashed and destroyed

    Hemodynamics optimization during off-pump coronary artery bypass: the 'no compression' technique

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    OBJECTIVE: Heart manipulation during OPCAB may cause hemodynamical instability in particular for access to the posterior and lateral walls. The 'no compression' technique involves enucleation of the heart without any compression on the cavities, and stabilization of the target area with a suction device. The impact of this technique on hemodynamics is assessed. METHODS: In order to analyze a homogeneous group, 26 consecutive patients with triple grafts, one to each side of the heart in the same sequential order (posterior, lateral and anterior wall successively) were selected. Heart rate (HR), mean pulmonary arterial pressure (PAP, mmHg), pulmonary capillary wedge pressure (PCWP, mmHg), mean arterial pressure (MAP, mmHg), cardiac output index (COI, l/min per m(2)), and central venous saturation (SvO(2),%) were monitored. A coronary shunt was used for all the anastomoses. RESULTS: HR was stable with baseline value of 60+/-10 and the highest value for the anterior wall, 63.6+/-8 (P=0.23). PAP and PCWP exhibited their highest increase, when compared with baseline, for the lateral wall, 23.9+/-4.7 vs. 20.7+/-6.2 (P=0.06), and 17.2+/-4.7 vs. 14.9+/-5.6 (P=0.16), respectively. MAP, COI and SvO(2), exhibited their largest drop, when compared with baseline, for the lateral wall too, 73.1+/-9.1 vs. 77.1+/-7.5 (P=0.12), 1.99+/-0.47 vs. 2.26+/-0.55 (P=0.09), and 70.5+/-8.4 vs. 74.8+/-9.3 (P=0.12), respectively. CONCLUSIONS: None of the hemodynamical parameter differed significantly from baseline value for all three territories. While hemodynamics was perfectly maintained during the posterior and anterior walls revascularization, exposure of the lateral wall led to marginal changes only
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