5,349 research outputs found

    Hydrophobicity properties of graphite and reduced graphene oxide of the polysulfone (PSf) mixed matrix membrane

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    Hydrophobicity properties of graphite and reduced graphene oxide (rGO) (from exfoliated graphite/rGO) towards PSf polymer membrane characteristic and properties at different additives weight concentrations (1, 2, 3, 4 and 5 wt. %) were investigated. Both PSF/graphite and PSf/rGO membranes were characterized in term of hydrophobicity, surface bonding, surface roughness and porosity. FTIR peaks revealed that membrane with graphite and reduced graphene oxide nearly diminished their O-H bonding which was opposite to the graphene oxide peak that shows a strong O-H bonding as increased exfoliated times. These results were in line with the contact angle results that showed strong hydrophobicity of graphite and reduced graphene oxide membranes as increased these additives concentration. The effect of strong hydrophobicity in these membranes also has resulted in smoother surface roughness compared to pristine PSf membrane. Further investigation of the performance of water flux also proved that both above membranes have strong hydrophobic effect, with the lowest pure water flux rate (L/m2h) was given by PSf/rGO 3% membrane at 19.2437 L/m2h

    Peer influence as a driver of technological innovation in the UK National Health Service: a qualitative study of clinicians’ experiences and attitudes

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    Background Accelerating innovation to improve quality is a key policy target for healthcare systems around the world. Effectively influencing individuals’ behaviour is crucial to the success of innovation initiatives. This study explores UK clinicians’ lived experiences of, and attitudes towards, clinical peers endorsing healthcare innovations. Methods Qualitative interviews with UK-based clinicians in one of two groups: (1) clinicians working in ‘front-line’ service provision and (2) clinicians in strategic leadership roles within health institutions. Participants were identified through purposive sampling, and participated in semistructured telephone interviews. Thematic analysis was used to identify and analyse themes in the data. Results 17 participants were recruited: eight clinicians from front-line UK healthcare settings and nine clinicians in leadership roles. Two major themes were identified from the interviews: power and trust. Participants recognised and valued peers’ powerful influence, exerted in person via social networks and routine work-related activities. Peers were implicitly trusted, although often on condition of their credibility and deservingness of respect, supporting evidence and absence of conflict of interest. While the groups shared similar views, they diverged on the subject of institutions, felt to be powerful by strategic leaders yet scarcely mentioned by front-line clinicians. Conclusions UK clinicians view peers as a powerful and trustworthy source to promote innovative technologies. Policies that aim to support this process should seek to control the wider conditions that nurture peer-to-peer influence. Further research into interpersonal influence in health settings may improve implementation of change initiatives

    Numerical Investigation of Heat Transfer Enhancement in a Circular Tube with Rectangular Opened Rings

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    Turbulent forced convection of coolant air flow (10 m/s velocity) in a steel tube of 50 cm long having outside diameter of 60 mm and inside diameter of 30 mm with constant outside surface temperature of 1000, 1200 and 1400 Ko is numerically analyzed. The renormalization group k-ε model is used to simulate turbulence in ANSYS - FLUENT 14.5. An opened ring of rectangular cross section (5x7 mm) is fitted in the tube and separated by 8cm pitch. Results of temperature and velocity distribution along the tube center line for the case of tube with internal ribs were compared with that of plain tube , these results show that the use of internal ribs enhance the heat transfer rate and found to possess the highest performance factors for turbulent flow

    Nutritional Evaluation and Physicochemical Properties of Fermented Shirezh Dairy Product

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    Many of the Kurdish traditional dairy products have not been studied thoroughly so far though are still produced at small scale. Dow (sour butter milk) and Shirezh are among these products. Shirezh known to Iraqi Kurds as sour concentrated Dow. The characteristics of Shirezh and Dow were: pH (5.5, 4.05), acidity (2.13%, 1.10%), total solids (18.70%, 5.32%), ash (0.62%, 0.45%), fat (2.57%, 0.8%) and total protein (13.59%, 3.28%) respectively, furthermore the amino acids of Shirezh’s protein found in balanced and acceptable quality. The aim of this research is to introduce Shirezh and Dow to scientific literature and to determine their characterization and nutritional values. Keywords: Shirezh, Dow, Dairy, Fermented, Nutrition, Physicochemical, Amino acids

    Calculation of Thermodynamic and Transport Properties of Less Simple Metals

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    Patterned silicon substrates: a common platform for room temperature GaN and ZnO polariton lasers

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    A new platform for fabricating polariton lasers operating at room temperature is introduced: nitride-based distributed Bragg reflectors epitaxially grown on patterned silicon substrates. The patterning allows for an enhanced strain relaxation thereby enabling to stack a large number of crack-free AlN/AlGaN pairs and achieve cavity quality factors of several thousands with a large spatial homogeneity. GaN and ZnO active regions are epitaxially grown thereon and the cavities are completed with top dielectric Bragg reflectors. The two structures display strong-coupling and polariton lasing at room temperature and constitute an intermediate step in the way towards integrated polariton devices

    Aromaticity of the doubly charged [8]circulenes

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    Magnetically induced current densities and current pathways have been calculated for a series of fully annelated dicationic and dianionic tetraphenylenes, which are also named [8]circulenes. The gauge including magnetically induced current (GIMIC) method has been employed for calculating the current density susceptibilities. The aromatic character and current pathways are deduced from the calculated current density susceptibilities showing that the neutral [8]circulenes have two concentric pathways with aromatic and antiaromatic character, respectively. The inner octatetraene core (the hub) is found to sustain a paratropic (antiaromatic) ring current, whereas the ring current along the outer part of the macrocycle (the rim) is diatropic (aromatic). The neutral [8]circulenes can be considered nonaromatic, because the sum of the ring-current strengths of the hub and the rim almost vanishes. The aromatic character of the doubly charged [8]circulenes is completely different: the dianionic [8]circulenes and the OC-, CH-, CH2-, SiH-, GeH-, SiH2-, and GeH2-containing dicationic species sustain net diatropic ring currents i.e., they are aromatic, whereas the O-, S-, Se-, NH-, PH- and AsH-containing dicationic [8]circulenes are strongly antiaromatic. The present study also shows that GIMIC calculations on the [8]circulenes provide more accurate information about the aromatic character than that obtained using local indices such as nuclear-independent chemical shifts (NICSs) and H-1 NMR chemical shifts.Peer reviewe

    Chemical and biological investigations of Delonix regia (Bojer ex Hook.) Raf.

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    U radu je opisana izolacija pet sastojaka petroleterske i diklormetanske frakcije metanolnog ekstrakta kore biljke Delonix regia: lupeol (1), epilupeol (2), β-sitosterol (3), stigmasterol (4) i p-metoksibenzaldehid (5). Nadalje, testirano je antimikrobno djelovanje različitih ekstrakata difuzijskom metodom na disku (15 μg mm2). Zone inhibicije za sastojke topljive u petroleteru, tetraklormetanu i diklormetanu bile su 914 mm, 1113 mm, odnosno 920 mm, dok je zona inhibicije standarda kanamicina bila 2025 mm. U biološkom pokusu smrtnosti morskih kozica najveću toksičnost pokazali su spojevi topljivi u tetraklormetanu (LC50 = 0,83 μg mL1), dok je topljivost sastojaka topljivih u petroleteru i diklormetanu bila LC50 14,94, odnosno 3,29 μg mL1, a standarda vinkristin sulfata 0,812 μg mL1. Ovo je prvo izvješće o izolaciji sastojaka, antimikrobnom djelovanju i citotoksičnosti biljke D. regia.In this study five compounds, lupeol (1), epilupeol (2), β-sitosterol (3), stigmasterol (4) and p-methoxybenzaldehyde (5) were isolated from the petroleum ether and dichloromethane fractions of a methanolic extract of the stem bark of Delonix regia. Antimicrobial screening of the different extracts (15 μg mm2) was conducted by disc diffusion method. The zones of inhibition demonstrated by the petroleum ether, carbon tetrachloride and dichloromethane fractions ranged from 914 mm, 1113 mm and 920 mm, respectively, compared to kanamycin standard with the zone of inhibition of 2025 mm. In brine shrimp lethality bioassay, the carbon tetrachloride soluble materials demonstrated the highest toxicity with LC50 of 0.83 μg mL1, while petroleum ether and dichloromethane soluble partitionates of the methanolic extract revealed LC50 of 14.94 and 3.29 μg mL1, respectively, in comparison with standard vincristine sulphate with LC50 of 0.812 μg mL1. This is the first report on compounds separation from D. regia, their antimicrobial activity and cytotoxicity

    Integration of global ring currents using the Ampere-Maxwell law

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    Magnetically induced ring currents are calculated from the magnetic shielding tensor by employing the Ampere-Maxwell law. The feasibility of the method is demonstrated by integrating the zz component of the shielding tensor along the symmetry axis of highly symmetric ring-shaped aromatic, antiaromatic and nonaromatic molecules. The calculated ring-current strengths agree perfectly with the ones obtained by integrating the current-density flux passing through a plane cutting half the molecular ring. The method can be used in combination with all electronic structure codes capable of calculating nuclear magnetic resonance (NMR) shielding tensors in general points in space. We also show that nucleus independent chemical shifts (NICS) along the symmetry axis are related to the spatial derivative of the strength of the global ring-current along the z axis.Peer reviewe

    Impact of meningitis on intelligence and development: A systematic review and meta-analysis

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    BACKGROUND: We undertook a systematic review and meta-analysis to address the question "what is the impact of meningitis on IQ and development." METHODS: Search: conducted using standardized search terms across Medline, PsychInfo and EMBASE to 06/2014. Eligibility: human studies of any infectious aetiology of meningitis reporting IQ or infant developmental age or stage outcomes. Quality: Centre for Evidence Based Medicine, Oxford, quality tools. Analysis: random effects meta-analysis by organism. RESULTS: 39 studies were included in the review, 34 providing data on IQ (2015 subjects) and 12 on developmental delay (382 subjects). Across all bacterial organisms, meningitis survivors had a mean IQ 5.50 (95% CI: -7.19, -3.80; I2 = 47%, p = 0.02) points lower than controls. IQ was significantly lower than controls for Neisseria meningitides (NM: 5 points) and Haemophilus influenzae b (Hib: 6 points) but not in viral meningitis, with only single studies included for Streptococcus pneumoniae (SP) and group B streptococcus (GBS). The pooled relative risk (RR) for low IQ (IQ<70) in survivors of bacterial meningitis compared with controls was 4.99 (95% CI: 3.17, 7.86) with no significant heterogeneity (I2 = 49%, p = 0.07). Developmental delay of approximately 0.5SD was reported in studies of bacterial meningitis but no delay in the only study of viral meningitis. CONCLUSIONS: We found moderate evidence that surviving bacterial meningitis has a deleterious impact on IQ and development but no evidence that viral meningitis had meaningful cognitive impacts. Survivors of bacterial meningitis should be routinely offered screening for cognitive deficits and developmental delay in addition to hearing loss
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