503 research outputs found

    Probing the interactions of phenol with oxygenated functional groups on curved fullerene-like sheets in activated carbon

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    The mechanism(s) of interactions of phenol with oxygenated functional groups (OH, COO and COOH) in nanopores of activated carbon (AC) is a contentious issue among researchers. This mechanism is of particular interest because a better understanding of the role of such groups in nanopores would essentially translate to advances in AC production and use, especially in regard to the treatment of organic-based wastewaters. We therefore attempt to shed more light on the subject by employing density functional theory (DFT) calculations in which fullerene-like models integrating convex or concave structure, which simulate the eclectic porous structures on AC surface, are adopted. TEM analysis, EDS mapping and Boehm titration are also conducted on actual phenol-adsorbed AC. Our results suggest the widely-reported phenomenon of decreased phenol uptake on AC due to increased concentration of oxygenated functional groups is possibly attributed to the increased presence of the latter on the convex side of the curved carbon sheets. Such a system effectively inhibits phenol from getting direct contact with the carbon sheet, thus constraining any available π–π interaction, while the effect of groups acting on the concave part of the curved sheet does not impart the same detriment

    Magnetic anisotropy reversal driven by structural symmetry-breaking in monolayer {\alpha}-RuCl3

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    Layered {\alpha}-RuCl3 is a promising material to potentially realize the long-sought Kitaev quantum spin liquid with fractionalized excitations. While evidence of this exotic state has been reported under a modest in-plane magnetic field, such behavior is largely inconsistent with theoretical expectations of Kitaev phases emerging only in out-of-plane fields. These predicted field-induced states have been mostly out of reach due to the strong easy-plane anisotropy of bulk crystals, however. We use a combination of tunneling spectroscopy, magnetotransport, electron diffraction, and ab initio calculations to study the layer-dependent magnons, anisotropy, structure, and exchange coupling in atomically thin samples. Due to structural distortions, the sign of the average off-diagonal exchange changes in monolayer {\alpha}-RuCl3, leading to a reversal of magnetic anisotropy to easy-axis. Our work provides a new avenue to tune the magnetic interactions in {\alpha}-RuCl3 and allows theoretically predicted quantum spin liquid phases for out-of-plane fields to be more experimentally accessible

    Inhibition of cytokine-mediated JNK signalling by purinergic P2Y11 receptors, a novel protective mechanism in endothelial cells

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    Previous research from our laboratory has demonstrated a novel phenomenon whereby GPCRs play a role in inhibiting cytokine-mediated c-Jun N-terminal kinase (JNK) signalling. So far this novel phenomenon seems to have been vastly overlooked, with little research in the area. Therefore, in this study we explored this further; by assessing the potential of P2YRs to mediate inhibition of cytokine-mediated JNK signalling and related functional outcomes in human endothelial cells. We utilised primary endothelial cells, and employed the use of endogenous activators of P2YRs and well characterised pharmacological inhibitors, to assess signalling parameters mediated by P2YRs, Interleukin-1β (IL-1β), TNFα and JNK. Activation of P2YRs with adenosine tri-phosphate (ATP) resulted in a time- and concentration-dependent inhibition of IL-1β-mediated phosphorylation of JNK and associated kinase activity. The effect was specific for cytokine-mediated JNK signalling, as ATP was without effect on JNK induced by other non-specific activators (e.g. sorbitol, anisomycin), nor effective against other MAPK pathways such as p38 and the canonical NFκB cascade. Pharmacological studies demonstrated a role for the P2Y11 receptor in mediating this effect, but not the P2Y1 nor the adenosine receptors (A1, A2A, A2B & A3). The novel Gαq/11 inhibitor YM254890 and a protein kinase A (PKA) inhibitor H89 both partially reversed ATP-mediated inhibition of IL-1β-stimulated JNK indicating involvement of both Gαq/11 and Gαs mediated pathways. ATP also partially reversed IL-1β-mediated induction of cyclo‑oxygenase-2 (COX-2) and E-selectin. Collectively, these studies indicate the potential for activation of purinergic receptors to protect the endothelium from inflammatory driven JNK activation and may be a new target for inflammatory disease therapy

    Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

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    Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

    Differential host utilisation by different life history stages of the fish ectoparasite Argulus foliaceus (Crustacea: Branchiura)

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    Contains fulltext : 72168.pdf (publisher's version ) (Open Access

    Development, prevalence and treatment of blood pressure abnormalities in spinal cord injury

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    © 2019 Min Yin GohDisorders of blood pressure control arise from disruption of the autonomic nervous system and result in symptomatic orthostatic hypotension and large fluctuations in blood pressure. Ambulatory blood pressure monitoring is used in the general population for assessment of blood pressure control and to detect episodes of hypotension. In spinal cord injury (SCI), impaired control of the sympathetic nervous system leads to orthostatic intolerance and autonomic dysreflexia. Smaller studies in restricted populations have examined ambulatory pressures in SCI and observed abnormalities in diurnal blood pressure variation in complete cervical SCI. Altered diurnal blood pressure is associated with abnormalities in diurnal urine production and orthostatic intolerance in autonomic failure. This triad may also occur in SCI to explain the orthostatic intolerance. A retrospective examination of ambulatory pressures of patients with SCI referred for clinically significant blood pressure disorders revealed a high prevalence of abnormalities in diurnal blood pressure and urine production in acute and chronic tetraplegia and in acute paraplegia. To characterise the course of diurnal blood pressure, urine production and orthostatic symptoms in SCI, two prospective studies were performed. First, consecutive patients admitted with acute SCI were screened for recruitment, and consenting volunteers were compared with immobilised and mobilising controls. In the second study, people with chronic SCI (>1 year) living in the community were compared with mobilising controls. Compared with mobilising and immobilised controls, there was a high prevalence of abnormal diurnal blood pressure variation in SCI. The abnormalities were most prevalent and marked in higher and earlier SCI. Abnormalities persisted over time in both complete and incomplete cervical SCI. Abnormalities in high paraplegia were no different to that of cervical SCI in early SCI, but were no different to that of controls in chronic SCI. Nocturnal hypertension occurred in the absence of day hypertension in SCI, thus clinic pressures may miss elevation in blood pressures and ambulatory monitoring may be beneficial in assessment of blood pressure in SCI. Abnormalities in diurnal urine production were present and persisted over time in cervical SCI, but appeared to improve over time with thoracic SCI, mirroring changes in diurnal blood pressure. Orthostatic hypotension and orthostatic intolerance were more prevalent in SCI than in controls. Mild orthostatic intolerance is common in chronic SCI and a small proportion had more severe symptoms. A single centre study to investigate a drug treatment for orthostatic intolerance in the setting of a loss of diurnal blood pressure variation was unsuccessful due to low recruitment rates. As life expectancy increases in the SCI population, there is evidence of increased rates of cardiovascular disease. Similar to the general population, the loss of diurnal blood pressure variation and elevated nocturnal pressures may be a contributor to the increased cardiovascular disease in SCI, and thus a potential therapeutic target. Ambulatory blood pressure monitoring may be useful to detect these changes and examination of a larger SCI population with a longer duration of follow up for cardiovascular disease may help to determine this

    Massive splenic epidermoid cyst in a child treated with laparoscopic partial splenectomy – case report and review of literature

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    Splenic cysts are extremely rare. We present the case of a young female child who presented with a massive splenic cyst arising from the lower pole of the spleen. We offered surgical intervention in view of persistent abdominal pain and the large size of the cyst, which was predisposing it to traumatic rupture and restricting the child’s normal activities. Cyst excision with splenic preservation was successfully achieved via a laparoscopic lower pole splenectomy. Histology confirmed a benign epidermoid cyst. The case presentation is followed by a brief review of literature

    Untangling the additive and multiplicative relations between natural scenery exposure and human-animal interaction on affective well-being: Evidence from daily diary studies

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    Built nature spaces have been increasingly integrated into our urban environments in recent years with the aim of reaping their psychological benefits. However, despite numerous works of research on the relationship between nature exposure and well-being, most studies have looked into the benefits of well-being from the lens of isolated elements of nature, such as natural scenery or animal exposure. This study aims to fill in the gaps by examining the additive and multiplicative relationships between natural scenery exposure and human–animal interaction on affective well-being (i.e., positive affect, negative affect, and stress) through a daily diary study. Over seven days, natural scenery exposure, human–animal interactions, and affective well-being of 514 young adults were assessed. Through multilevel modelling, we found that natural scenery exposure was associated with increased positive affect at the within- and between-person levels. Moreover, human–animal interaction was associated with increased positive affect at the within-person level. No evidence was found for human–animal interaction as a moderator of the relationship between natural scenery exposure and affective well-being. Our findings support the additive, but not multiplicative, relations between natural scenery exposure and human–animal interactions on their influence on affective well-being. The exploratory analysis showed the lack of multiplicative relationship which can be attributed to the distinct mechanism of the effect between natural scenery exposure and human–animal interactions on affective well-being

    Sharing plates : cooking and coping with cancer.

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    This paper presents the collaboration between National Cancer Centre Singapore (NCCS) and a group of six final-year students from Wee Kim Wee School of Communication and Information, Nanyang Technological University (NTU) in an inaugural campaign that aims to produce and promote Sharing Plates—the first local cookbook by the cancer community to the cancer community. Leveraging on 12 patient profile stories and 40 recipes of homemade dishes, the cookbook serves as a communication platform to a) demystify cancer diet and nutrition by clarifying the fact that cancer patients are able to enjoy everyday food with only minimal alterations in diet and b) inspire and encourage cancer patients and caregivers through uplifting anecdotes as well as campaign events that promote the support network of fellow members of the cancer community. The campaign also aims to emphasise NCCS’ role as a holistic organisation by increasing its focus on nutritional needs of cancer patients. This paper details the research that directed the conceptualisation of the cookbook and campaign strategy. It also focuses on various elements of the campaign, with a final discussion on post-campaign evaluation as well as limitations and future recommendations.Bachelor of Communication Studie
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