40 research outputs found

    Studies of solute-solvent interactions and miceller behaviour of complexes of copper (II) palmitate with substituted phenylthiourea and 2-amino benzothiazole in methanol-benzene mixture

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    In this work, synthesis of copper (II) surfactants followed by the complexation of each other with the molar ratio of 1:2 dissolving in ethanol have been reported. The purity of the resulting complexes of the general formula- CP(PTU )T , CP(BTA)T was checked by thin layer chromatography and characterized on the basis of elemental analysis. Their spectral studies are also included and data suggest that Cu (II) phenylthiourea mixed system binds through the donor ability of nitrogen to transition metal. The magnetic moment studies suggest the dimeric nature of the complexes. IR, NMR, ESR spectral details confirm that complexation has taken place successfully and dada suggest that the complexes possess elongated octahedral geometry. Density, Molar Volume, Apparent Molar Volume of these complexes was investigated in non-aqueous solvent at various concentrations by Springel Pyknometer to understand the nature, critical micelle concentration and micelle characteristics of the complexes. Overall, the CMC values were found to be decreased with increasing average molecular weight of soap complex. The solute - solute interactions were found to be greater before CMC whereas solute-solvent interactions were found greater after CMC

    Cellulose an ageless renewable green nanomaterial for medical applications: an overview of ionic liquids in extraction, separation and dissolution of cellulose

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    Cellulose is a renewable natural fiber, which has gained enormous and significant research interest and evolved as the prime and promising candidate for replacing synthetic fibers. The various sources of cellulose, which is one of the world's most ubiquitous and renewable biopolymer resources, include trees, plants, tunicate and bacteria. The renewable biomaterial in the form of nanocellulose and its composites have been included in this review having the broad range of medical applications, viz.; tissue engineering, cardiovascular surgery, dental, pharmaceuticals, veterinary, adhesion barriers and skin therapy. These grafts are being fabricated from biodegradable materials. Bacterial cellulose is also an emerging renewable biomaterial with immense potential in biomedical field. The fabrication methods, characteristic properties and various overwhelming applications of cellulosic composites are explicitly elucidated in this review. The crux of this review is to exhibit the latest state of art, development in the field of cellulosic nanocomposite science and technology research and their applications towards biomedical field. Among the fourteen principle of green chemistry the two key principles i.e. using environmentally preferable solvents and bio-renewable feed-stocks covers in dissolution of cellulose in ionic liquids (ILs). In addition, this review covers about the comprehensive extraction and dissolution of cellulose and nanocellulose using ILs.publishe

    Fine particulate matter in the tropical environment: monsoonal effects, source apportionment, and health risk assessment

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    The health implications of PM2:5 in the tropical region of Southeast Asia (SEA) are significant as PM2:5 can pose serious health concerns. PM2:5 concentration and sources here are strongly influenced by changes in the monsoon regime from the south-west quadrant to the north-east quadrant in the region. In this work, PM2:5 samples were collected at a semi-urban area using a high-volume air sampler at different seasons on 24 h basis. Analysis of trace elements and water-soluble ions was performed using inductively coupled plasma mass spectroscopy (ICP-MS) and ion chromatography (IC), respectively. Apportionment analysis of PM2:5 was carried out using the United States Environmental Protection Agency (US EPA) positive matrix factorization (PMF) 5.0 and a mass closure model. We quantitatively characterized the health risks posed to human populations through the inhalation of selected heavy metals in PM2:5. 48% of the samples collected exceeded the World Health Organization (WHO) 24 h PM2:5 guideline but only 19% of the samples exceeded 24 h US EPA National Ambient Air Quality Standard (NAAQS). The PM2:5 concentration was slightly higher during the north-east monsoon compared to south-west monsoon. The main trace metals identified were As, Pb, Cd, Ni, Mn, V, and Cr while the main ions were SO

    Kajian jati diri kakitangan dalam organisasi Universiti Kebangsaan Malaysia

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    Isu jati diri merupakan aspek penting dalam organisasi untuk memupuk penglibatan dan rasa setia individu terhadap organisasi. Berlandaskan konsep jati diri, kajian ini bertujuan untuk mengetahui konsep jati diri dalam kalangan warga Universiti Kebangsaan Malaysia (UKM), di mana hasil kajian ini akan dapat mengenal pasti perkara yang perlu dilakukan untuk memupuk perasaan jati diri terhadap UKM. Teori yang mendasari kajian ini ialah teori Identiti Sosial (Turner & Tajfel, 1979). Kajian ini mensasarkan penyertaan warga kerja di peringkat pengurusan tertinggi dan profesional, ahli-ahli akademik dan kakitangan pelaksana. Instrumen kajian ialah sesi tembual. Soalan termubual dibangunkan berdasarkan tiga konstruk jati diri, iaitu setia, sayang dan bangga. Analisis data menunjukkan terdapat pemahaman jati diri yang berbeza dalam kalangan kakitangan UKM di mana ianya bergantung kepada jawatan kumpulan sasar tersebut. Walaupun terdapat perbezaan di mana segilintir responden bersedia untuk meninggalkan UKM sekiranya mereka mendapat tawaran yang lebih baik dari organisi luar, secara umum kakitangan UKM mempunyai semangat setia, sayang dan bangga yang agak tinggi dan positif terhadap UKM. Kajian lanjut pada masa hadapan boleh dilakukan bagi merungkai permasalahan yang timbul dalam kalangan warga UKM agar usaha memperkukuh jati diri UKM dapat dilaksanakan dengan lebih mantap dan komprehensif

    Left atrial function in heart failure with preserved ejection fraction:a systematic review and meta-analysis

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    Aims Left atrial (LA) mechanical function may play a significant role in the development and progression of heart failure with preserved ejection fraction (HFpEF). We performed a systematic review and meta-analysis to evaluate association of impaired LA function with outcomes in HFpEF. Methods and results Multiple databases were searched for original studies measuring different phases of LA function in HFpEF patients. Comparative LA function between HFpEF patients and healthy controls was assessed by pooling weighted mean differences (WMD). Adjusted hazard ratios (HRs) with 95% confidence intervals were pooled to evaluate the prognostic utility of LA function. Twenty-two studies (2 trials, 20 observational) comprising 1974 HFpEF patients and 751 healthy controls were included. HFpEF patients had decreased LA reservoir [WMD = -12.21% (-15.47, -8.95); P <0.001], LA conduit [WMD = -5.68% (-8.56, -2.79); P <0.001], and pump [WMD = -11.07% (-14.81, -7.34); P <0.001] emptying fractions compared with controls. LA reservoir [WMD = -13.38% (-16.07, -10.68); P <0.001], conduit [WMD = -4.09% (-6.77, -1.42); P = 0.003], and pump [WMD = -3.53% (-4.47, -2.59); P <0.001] strains were also significantly lower in HFpEF patients. Decreased LA reservoir strain [HR 1.24 (1.02, 1.50); P = 0.03] was significantly associated with risk of composite all-cause mortality or heart failure hospitalization. Conclusions Impaired LA function appears to have diagnostic and prognostic value in HFpEF, but whether indices of LA function truly refine discrimination for diagnosis or prognosis remains to be fully determined. Larger studies are needed to better evaluate associations between LA function and clinical outcomes and the role of LA function as a target for novel HFpEF therapies

    Freedom of expression, accountability and development in the Arab region

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    Mechanisms for ensuring government transparency and accountability have yet to become established in the Arab region, where oil rents and security rents have traditionally enabled governments to provide jobs and services without having to rely heavily, if at all, on raising revenue through personal income tax on citizens. Yet various forms of resource mobilisation, which will be needed in future, are likely to require a greater degree of accountability from those responsible for such mobilisation. This paper considers whether a move in this direction is under way. It reviews government approaches to freedom of expression in the media and among non-governmental organisations. It notes changes that have taken place in this sphere since the start of the 1990s, not all of them positive, and concludes that many more steps remain to be taken if media organisations and NGOs are to exert pressure for accountability on behalf of citizens, and especially the disadvantaged

    Characterisation of particle mass and number concentration on the east coast of the Malaysian Peninsula during the northeast monsoon

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    Particle mass concentrations (PM10, PM2.5 and PM1) and particle number concentration ((PNC); 0.27 μm ≤ Dp ≤ 34.00 μm) were measured in the tropical coastal environment of Bachok, Kelantan on the Malaysian Peninsula bordering the southern edge of the South China Sea. Statistical methods were applied on a three-month hourly data set (9th January to 24th March 2014) to study the influence of north-easterly winds on the patterns of particle mass and PNC size distributions. The 24-h concentrations of particle mass obtained in this study were below the standard values detailed by the Recommended Malaysian Air Quality Guideline (RMAQG), United States Environmental Protection Agency (US EPA) and European Union (EU) except for PM2.5, which recorded a 24-h average of 30 ± 18 μg m-3 and exceeded the World Health Organisation (WHO) threshold value (25 μg m-3). Principal component analysis (PCA) revealed that PNC with smaller diameter sizes (0.27-4.50 μm) showed a stronger influence, accounting for 57.6% of the variability in PNC data set. Concentrations of both particle mass and PNC increased steadily in the morning with a distinct peak observed at around 8.00 h, related to a combination of dispersion of accumulated particles overnight and local traffic. In addition to local anthropogenic, agricultural burning and forest fire activities, long-range transport also affects the study area. Hotspot and backward wind trajectory observations illustrated that the biomass burning episode (around February-March) significantly influenced PNC. Meteorological parameters influenced smaller size particles (i.e. PM1 and Dp (0.27-0.43 μm)) the most
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