855 research outputs found

    Turbulent convective heat transfer and pressure drop of dilute CuO (copper oxide) - water nanofluid Inside a circular tube

    Get PDF
    This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.Turbulent forced convective heat transfer and pressure drop of 0.01 vol.% CuO-water nanofluid was assessed experimentally. The nanofluids were made flow into a heated horizontal tube under uniform constant heat flux within Reynolds number range of 11,500 to 32,000. The first objective is to know how close traditional correlation/formula for, both, heat transfer and pressure drop can predict nanofluid’s heat transfer and pressure drop. The second is to know how nanofluid’s convective heat transfer and pressure drop are compared to those of its base fluid; in this case water. The results showed that the abovementioned characteristics of the nanofluid can be predicted by the traditional correlation available. It is also found that the nanofluid’s Nusselt number and friction factor, which represent the heat transfer rate and pressure drop, respectively, are close to those of water. Hence, there is no anomaly due to the dispersed nanoparticles within the water.KACST (King Abdulaziz City for Science and Technology

    A systematic review of outcome measures used in clinical trials of treatment interventions following traumatic dental injuries

    Get PDF
    Background: Traumatic dental injuries (TDI) are common, andappropriate treatment will maximize the chances of maintaining teeth infunction while safeguarding their longevity and aesthetics. Subjectively, itappears that outcome measures used in studies investigating TDI arenumerous and diverse. Objectives: To undertake a systematic review ofthe outcomes used in clinical trials of treatment interventions followingTDI. Data sources: The MEDLINE, Cochrane Central Register of Con-trolled Trials, Cochrane Database of Systematic Reviews and EMBASEdatabases were searched up to June 2014. Reference lists of eligible studieswere cross-checked to identify additional studies and strategies to identifygrey literature and ongoing trials were employed. Study selection: Twoauthors independently assessed studies for inclusion and undertook dataextraction. The study designs included were as follows: systematic reviewswith/without meta-analyses, randomized and pseudo-randomized con-trolled trials and controlled clinical trials. There were no language restric-tions. Results: Ten studies confined to two types of TDI were included:avulsion (5) and non-vital immature permanent incisor teeth (5). The out-comes reported predominantly concentrated on injury activity and thephysical consequence of injury. There was little consistency between studiesfor the length of follow up, the time points at which outcomes were evalu-ated or the methods used to measure them. Conclusions: There is signifi-cant heterogeneity in outcomes reported for TDI in the literature. Thesefindings preclude meaningful meta-analysis between studies. Future clinicalstudies need to consider collecting a more consistent and wider range ofoutcomes, which should include one or more from each of the followingdomains: health resources utilisation, adverse effects and quality of life andfamily outcome. There is a clear need for the development of a Core Out-come Set for TDI using robust and established methodology, thus optimiz-ing the value of future research

    The Effect of Cultural Competency Training Programs on Expatriate Nurses\u27 Levels of Cultural Competence in Saudi Arabia as Measured by The Inventory for Assessing the Process of Cultural Competence (IAPCC-R)

    Get PDF
    The study examined the relationship between cultural competence training programs and the levels of cultural competence among expatriate nurses in Saudi Arabia. Cultural competence training programs are believed to increase the awareness of expatriate nurses in Saudi Arabia in regards to issues that might arise from cultural differences between patients and healthcare providers. Healthcare professionals, and healthcare organizations, emphasize the importance of culturally competent healthcare environments in providing optimum healthcare services to individuals from different cultural backgrounds. Findings from the study suggested that participation in cultural competency training is associated to higher cultural competency scores. Additionally, age was positively associated to cultural competency scores. Conclusions drawn from this study provide insights on the potential contribution of cultural competence training programs in the area of cultural competency development among healthcare workers. Keywords: Cultural competency, diversity, training programs, expatriate nurses

    Biomarkers-Directed Strategies to Treat Autism

    Get PDF
    Autism is a neurodevelopmental disorder characterized by social, communication, and behavioral symptoms. Recent research has attempted to identify the potential mechanisms that may contribute to the pathogenesis of autism. Biomarkers as noninvasive quantitative biological measures with accurate indication of a specific mechanism can lead to a better understanding of the pathogenesis required to design the most effective treatments of autism. There is also great hope that the discovery of valid and predictive biomarkers for this disorder will help earlier and more targeted methods for diagnosis and intervention. In this chapter, we discuss some of the current theorized mechanisms contributing to autism, including inflammation, oxidative stress, impaired detoxification, glutamate excitotoxicity, gut-microbiota-brain axis, impaired fatty acid profiling, and serotonin (5-HT)/oxytocin (OT) abnormalities as target to treat autism. Moreover, based on our understanding of the role of these mechanisms, selected treatment strategies are suggested. These strategies include nutraceuticals, probiotics/prebiotics and ω-3 supplementation, targeting glutamate transporters or selective 5-HT reuptake inhibitors, and intranasal OT treatment. Of course, the joint efforts of scientists, caregivers, and other stakeholders must combine to identify valid, clinically useful autism biomarkers that may lead to efficient treatment strategy and/or combined strategies

    On the Toxicity of Therapeutically Used Nanoparticles: An Overview

    Get PDF
    Human beings have been exposed to airborne nanosized particles throughout their evolutionary stages, and such exposures have increased dramatically over the last century. The rapidly developing field of nanotechnology will result in new sources of this exposure, through inhalation, ingestion, and injection. Although nanomaterials are currently being widely used in modern technology, there is a serious lack of information concerning the human health and environmental implications of manufactured nanomaterials. Since these are relatively new particles, it is necessary to investigate their toxicological behavior. The objective of this review was to trace the cellular response to nanosized particle exposure. Therapeutic application of selected nanoparticles together with their range of toxic doses was also reviewed. Effect of therapeutically used nanoparticles on cell membrane, mitochondrial function, prooxidant/antioxidant status, enzyme leakage, DNA, and other biochemical endpoints was elucidated. This paper highlights the need for caution during the use and disposal of such manufactured nanomaterials to prevent unintended environmental impacts

    Strength and durability of composite concretes using municipal wastes

    Get PDF
    The influence of different types of polyethylene (PE) substitutions as partial aggregate replacement of micro-steel fiber reinforced self-consolidating concrete (SCC) incorporating incinerator fly ash was investigated. The study focuses on the workability and hardened properties including mechanical, permeability properties, sulfate resistance and microstructure. Regardless of the polyethylene type, PE substitutions slightly decreased the compressive and flexural strength of SSC initially, however, the difference was compensated at later ages. SEM analysis of the interfacial transition zone showed that there was chemical interaction between PE and the matrix. Although PE substitutions increased the permeable porosity and sorptivity, it significantly improved the sulfate resistance of SCC. The influence of PE shape and size on workability and strength was found to be more important than its type. When considering the disposal of PE wastes and saving embodied energy, consuming recycled PE as partial aggregate replacement was more advantageous over virgin PE aggregate replaced concrete

    Neurotoxins and Autism

    Get PDF
    Recently, a great concern has risen about the increasing prevalence of autism as a neurodevelopmental disorder. Environmental factors as significant contributors to children’s health through a wide range of routes are linked to remarkable increases in this disorder. It is well known and accepted that young children are more vulnerable to environmental toxins, compared to adults. Modern day lifestyles with more mercury and lead exposures, fast food, cell phones, and microwaves place children at higher risk of neurotoxicity. Moreover, a huge number of synthetic chemicals termed as high-production-volume (HPV) chemicals are found in many products such as medications, cosmetics, building materials, plastic, and car fuels. These HPVs highly contribute to brain damage in developing infants. Other environmental toxins include thalidomide, valproic acid, misoprostol, and many infectious agents among which are pathogenic bacteria or their metabolites are found to be neurotoxic and/or linked to incidences of autism. This chapter summarizes the most important routes of exposure to environmental neurotoxins and explains how these toxins are related to the remarkable increase in the prevalence of autism through different etiological mechanisms such as oxidative stress, neuroinflammation, impaired neurochemistry and glutamate excitotoxicity

    Differential Redox Regulation of ORAI Ion Channels: A Mechanism to Tune Cellular Calcium Signaling

    Get PDF
    Reactive oxygen species (ROS) are involved in many physiological and pathophysiological cellular processes. We used lymphocytes, which are exposed to highly oxidizing environments during inflammation, to study the influence of ROS on cellular function. Calcium ion (Ca2+) influx through Ca2+ release–activated Ca2+ (CRAC) channels composed of proteins of the ORAI family is essential for the activation, proliferation, and differentiation of T lymphocytes, but whether and how ROS affect ORAI channel function have been unclear. Here, we combined Ca2+ imaging, patch-clamp recordings and measurements of cell proliferation and cytokine secretion to determine the effects of hydrogen peroxide (H2O2) on ORAI channel activity and human T helper lymphocyte (TH cell) function. ORAI1, but not ORAI3, channels were inhibited by oxidation by H2O2. The differential redox sensitivity of ORAI1 and ORAI3 channels depended mainly on an extracellularly located reactive cysteine, which is absent in ORAI3. TH cells became progressively less redox-sensitive after differentiation into effector cells, a shift that would allow them to proliferate, differentiate, and secrete cytokines in oxidizing environments. The decreased redox sensitivity of effector TH cells correlated with increased expression of Orai3 and increased abundance of several cytosolic antioxidants. Knockdown of ORAI3 with small-interfering RNA rendered effector TH cells more redox-sensitive. The differential expression of Orai isoforms between naïve and effector TH cells may tune cellular responses under oxidative stress
    corecore