Synthesis of bio-based thermoplastic polyurethane elastomers containing isosorbide and polycarbonate diol and their biocompatible properties.

A new family of highly elastic polyurethanes (PUs) partially based on renewable isosorbide were prepared by reacting hexamethylene diisocyanate with a various ratios of isosorbide and polycarbonate diol 2000 (PCD) via a one-step bulk condensation polymerization without catalyst. The influence of the isorsorbide/PCD ratio on the properties of the PU was evaluated. The successful synthesis of the PUs was confirmed by Fourier transform-infrared spectroscopy and (1)H nuclear magnetic resonance. The resulting PUs showed high number-average molecular weights ranging from 56,320 to 126,000 g mol(-1) and tunable Tg values from -34 to -38℃. The thermal properties were determined by differential scanning calorimetry and thermogravimetric analysis. The PU films were flexible with breaking strains from 955% to 1795% at from 13.5 to 54.2 MPa tensile stress. All the PUs had 0.9-2.8% weight lost over 4 weeks and continual slow weight loss of 1.1-3.6% was observed within 8 weeks. Although the cells showed a slight lower rate of proliferation than that of the tissue culture polystyrene as a control, the PU films were considered to be cytocompatible and nontoxic. These thermoplastic PUs were soft, flexible and biocompatible polymers, which open up a range of opportunities for soft tissue augmentation and regeneration

Potency of partially purified anthocyanin from leaf extract of Guiera senegalensis against carbon tetrachloride-induced lipoperoxidation in rats

Anthocyanin was extracted and partially purified from the ethanolic leaf extract of Guiera senegalensis (GS). The recovered anthocyanin extract was found to have a concentration of 8mg/cm3 and an absorption spectrum with peak at 268nm. In order to assess the preventive action of the anthocyanin against lipoperoxidation, serum malondialdehyde (MDA) was analyzed in rats administered with 1mg/kg of the anthocyanin before induction of lipoperoxidation in the rats using carbon tetrachloride (CC14). Serum MDA was also analyzed in rats administered with 1 and 2 mg/kg of anthocyanin for up to seven (7) days after induction of lipoperoxidation in the rats in order to determine the curative effect of the extract. The results suggest that anthocyanin extracted from GS leaves are more effective in the cure than prevention of lipoperoxidation, and the most effective daily dose of treatment is 1mg/kg for 7 days. Key words: Guiera senegalensis, Anthocyanin, Potency, Lipoperoxidatio

Correlation and path coefficient analysis of yield and agronomic characters among open pollinated maize varieties and their F1 hybrids in a diallel cross

A two-year study was conducted on maize (Zea mays L.) at the University of Ilorin Teaching and Research Farm Ilorin, Nigeria, during 2005 and 2006 growing seasons. The objective was to investigate correlation between grain yield and other agronomic parameters using 10 open-pollinated maize varieties and their 45 F1 hybrids in a half diallel. Positive and significant phenotypic and genotypic correlations were found for days to 50% tasselling with plant and ear height, and grain yield with plant height, number of grains ear-1 and ear weight. Positive and significant environmental correlation was also recorded for grain yield with plant and ear height, and ear weight. The path analysis revealed that, days to 50% silking, ear weight and number of grains ear-1 had the highest direct effect on grain yield, while number of grains ear-1 had the highest moderate indirect negative effects on grain yield. Days to flowering, plant and ear height, number of grains ear-1 and ear weight could be the important selection criteria in improving open pollinated maize varieties and hybrids for high grain yield

Carbon dynamics of Deep Bay, eastern Pearl River Estuary, China. I: a mass balance budget and implications for shorebird conservation

Deep Bay is a shallow embayment (112 km2) in the eastern Pearl River Estuary, China, and comprises 4 major wetland components: (1) a shallow brackish water body of 2.9 m average depth, (2) 2700 ha of intertidal mudflat, (3) 200 ha of tidal mangroves and (4) 300 ha of traditional tidal aquaculture ponds excavated in the mid-to-high intertidal region. A carbon budget is proposed for Deep Bay based on published information on the 4 major landscape components. Despite the usual emphasis placed on the role of mangroves as net carbon exporters in support of consumer (such as shorebird) populations, the carbon budget suggests that about 50% of all carbon available in Deep Bay originates from anthropogenic input from rapidly urbanising, as well as agricultural, areas in the local catchments. Mangrove production only contributes about 1.8% of the total carbon available in Deep Bay. Calculations based on the basal metabolic demands of the bird assemblage in winter suggest that the Deep Bay mudflats are close to carrying capacity. The annual carbon requirements of the shorebirds and availability (as demonstrated by the supply/demand ratio for the curlew) are lowest in the winter months, when bird numbers are large but production low. Considering the shorebird assemblage foraging on the mudflat, the total carbon consumption in January 1994 amounted to 16.9 t, while the carbon production during the same period was 27.8 t. These figures suggest that Deep Bay is near carrying capacity unless >50% of the invertebrate resources are made available to the birds. The results of this study also argue that organic enrichment in Deep Bay, which has usually been regarded as a 'pollutant', forms the basis of the major beneficial use of carbon (shorebird conservation), although further enrichment may result in negative impacts. This study highlights the importance of incorporating human influences into the study of the structure and function of ecosystems in urban settings.published_or_final_versio

Carbon dynamics of Deep Bay, eastern Pearl River Estuary, China. I: a mass balance budget and implications for shorebird conservation

Deep Bay is a shallow embayment (112 km2) in the eastern Pearl River Estuary, China, and comprises 4 major wetland components: (1) a shallow brackish water body of 2.9 m average depth, (2) 2700 ha of intertidal mudflat, (3) 200 ha of tidal mangroves and (4) 300 ha of traditional tidal aquaculture ponds excavated in the mid-to-high intertidal region. A carbon budget is proposed for Deep Bay based on published information on the 4 major landscape components. Despite the usual emphasis placed on the role of mangroves as net carbon exporters in support of consumer (such as shorebird) populations, the carbon budget suggests that about 50% of all carbon available in Deep Bay originates from anthropogenic input from rapidly urbanising, as well as agricultural, areas in the local catchments. Mangrove production only contributes about 1.8% of the total carbon available in Deep Bay. Calculations based on the basal metabolic demands of the bird assemblage in winter suggest that the Deep Bay mudflats are close to carrying capacity. The annual carbon requirements of the shorebirds and availability (as demonstrated by the supply/demand ratio for the curlew) are lowest in the winter months, when bird numbers are large but production low. Considering the shorebird assemblage foraging on the mudflat, the total carbon consumption in January 1994 amounted to 16.9 t, while the carbon production during the same period was 27.8 t. These figures suggest that Deep Bay is near carrying capacity unless >50% of the invertebrate resources are made available to the birds. The results of this study also argue that organic enrichment in Deep Bay, which has usually been regarded as a 'pollutant', forms the basis of the major beneficial use of carbon (shorebird conservation), although further enrichment may result in negative impacts. This study highlights the importance of incorporating human influences into the study of the structure and function of ecosystems in urban settings.published_or_final_versio

Polysaccharides from wolfberry antagonizes glutamate excitotoxicity in rat cortical neurons

Glutamate excitotoxicity is involved in many neurodegenerative diseases including Alzheimer's disease (AD). Attenuation of glutamate toxicity is one of the therapeutic strategies for AD. Wolfberry (Lycium barbarum) is a common ingredient in oriental cuisines. A number of studies suggest that wolfberry has anti-aging properties. In recent years, there is a trend of using dried Wolfberry as food supplement and health product in UK and North America. Previously, we have demonstrated that a fraction of polysaccharide from Wolfberry (LBA) provided remarkable neuroprotective effects against beta-amyloid peptide-induced cytotoxicity in primary cultures of rat cortical neurons. To investigate whether LBA can protect neurons from other pathological factors such as glutamate found in Alzheimer brain, we examined whether it can prevent neurotoxicity elicited by glutamate in primary cultured neurons. The glutamate-induced cell death as detected by lactate dehydrogenase assay and caspase-3-like activity assay was significantly reduced by LBA at concentrations ranging from 10 to 500 μg/ml. Protective effects of LBA were comparable to memantine, a non-competitive NMDA receptor antagonist. LBA provided neuroprotection even 1 h after exposure to glutamate. In addition to glutamate, LBA attenuated N-methyl-d-aspartate (NMDA)-induced neuronal damage. To further explore whether LBA might function as antioxidant, we used hydrogen peroxide (H2O2) as oxidative stress inducer in this study. LBA could not attenuate the toxicity of H2O2. Furthermore, LBA did not attenuate glutamate-induced oxidation by using NBT assay. Western blot analysis indicated that glutamate-induced phosphorylation of c-jun N-terminal kinase (JNK) was reduced by treatment with LBA. Taken together, LBA exerted significant neuroprotective effects on cultured cortical neurons exposed to glutamate. © 2009 Springer Science+Business Media, LLC.postprin

Neuroprotective effects of minocycline on double-stranded RNA-induced neurotoxicity in cultured cortical neurons

1. Minocycline, memantine,and glycoconjugate were assessed for their ability to protect cultured primary cortical neurons against double-stranded RNA-induced neurotoxicity. 2. Minocycline but not memantine or glycoconjugate protected cultured cells and warrants further investigation.published_or_final_versio

MODUL PELATIHAN SD KELAS TINGGI KELOMPOK KOMPETENSI B

Modul ini membahas dua kompetensi bagi guru SD Kelas Tinggi, yakni kompetensi PROFESIONAL tentang KAJIAN BILANGAN DAN STATISTIKA SEKOLAH DASAR; dan kompetensi PEDAGOGIK tentang Teori Belajar dan Prinsip Pembelajara

Carbon nanotube four-terminal devices for pressure sensing applications

Carbon nanotubes (CNTs) are of high interest for sensing applications,owing to their superior mechanical strength, high Young’s modulus and low density. In this work, we report on a facile approach for the fabrication of carbon nanotube devices using a four terminal configuration. Oriented carbon nanotube films were pulled out from a CNT forest wafer and then twisted into a yarn. Both the CNT film and yarn were arranged on elastomer membranes/diaphragms which were arranged on a laser cut acrylic frame to form pressure sensors. The sensors were calibrated using a precisely controlled pressure system, showing a large change of the output voltage of approximately 50 mV at a constant supply current of 100 μA and under a low applied pressure of 15 mbar. The results indicate the high potential of using CNT films and yarns for pressure sensing applications