AKTIVITAS ANTIOKSIDAN SEDIAAN NANOPARTIKEL KITOSAN EKSTRAK ETANOL KELOPAK ROSELA (Hibiscus sabdariffa L) PADA TIKUS HIPERKOLESTEROL : PENGUKURAN KADAR MALONDIALDEHID (MDA)

Hypercholesterolemia can induce oxidative stress and are associated with atherosclerosis and other cardiovascular disorders. Administration of a preparation of chitosan nanoparticles roselle extract (NKER) can prevent oxidative stress because it contains flavonoids which have an effect as an antioxidant anthocyanin. Decreased oxidative stress can be determined by measuring the levels of malondealdehid (MDA) produced by the reaction of lipid peroxidation. The purpose of this study was to determine the effect of administration of a preparation of chitosan nanoparticles roselle calyx ethanol extract of antioxidant activity by measuring the levels of MDA. This study used 25 adult rats of Sprague Dawley strain were divided into 5 groups. The first group was given a standard feed diet as baseline, group II was induced with pure cholesterol. Group III, IV and V induced pure cholesterol as well as the dosage given NKER with successive doses of 25 mg/kg, 50 mg/kg and 100 mg/KgBB. The treatment was done for 30 days. On day - 31 each rat blood taken for measurement of total cholesterol, as well as the measurement of MDA using thiobarbituric acid reactive substance (TBARS). The results showed an increase in levels of MDA in mice induced pure cholesterol (group II) with a mean concentration of 7.13 ± 0.22 nmol / ml significantly different to the baseline with a mean concentration of 0.87 ± 0.77 nmol / ml (p≤0,05). The mean levels of MDA in group III, IV and V respectively was 5.49 ± 0.18 nmol / ml; 4.18 ± 0.37 nmol / ml; and 2.18 ± 0.15 nmol / ml,significantly different when compared with the baseline group and the group II (p≤0,05). Decreased levels of MDA in mice given dosage NKER hypercholesterolemia showed that nker preparations have antioxidant activity, which is owned by the highest antioxidant activity NKER dosage dose 100mg/KgBB. Keywords : Antioxidant, Nanoparticles, Roselle, malondialdehyd

Learning in Hybrid-Project Systems: The Effects of Project Performance on Repeated Collaboration

This study advances contingency theories of performance-outcome learning in hybrid-project systems, in which both project participants and superordinate organizations influence the formation of project ventures. We propose that performance-outcome learning depends on the perceived relevance of prior performance and on organizational control over project participants. We examine this framework using data on 239 U.S. movie projects from the years 1931-40. In keeping with our theory, higher project performance led to future collaborations with the same partners, contingent on prior collaborations, project similarity, and organizational control. Our findings imply distinct patterns of network evolution and unfolding adaptation of hybrid-project systems through slow-moving, local adjustments

Manipulating the Formation of NH₄TiOF₃ Mesocrystals: Effects of Temperature, Surfactant, and pH

There are two main competitive processes involved in the formation of NH₄TiOF₃ mesocrystals. One leads to the assembly of individual NH₄TiOF₃ nanocrystals and the subsequent formation of NH₄TiOF₃ mesocrystals. The other converts the NH₄TiOF₃ nanocrystals into TiO₂ (anatase) nanoparticles and results in the subsequent formation of TiO₂ aggregates. Surfactant (Brij 58) molecules appear to facilitate the mesoscale assembly of NH₄TiOF₃ nanocrystals into NH₄TiOF₃ mesocrystals via the interaction of their hydrophobic tails. Elevated temperature and higher solution pH (adjusted by ammonia solution) increase the conversion rate of NH₄TiOF₃ nanocrystals into TiO₂ (anatase) nanoparticles. This conversion process reduces the amount of NH₄TiOF₃ nanocrystals available for the mesoscale assembly and consequently increases the pore volume of the resultant NH₄TiOF₃ mesocrystals. Fluorination and {001} facets affect the photocatalytic performance of the calcined products (anatase TiO₂) of the NH₄TiOF₃ mesocrystals. The present study demonstrates the key parameters that control the formation and stability of NH₄TiOF₃ mesocrystals and the photocatalytic behavior of nanocrystalline TiO₂ derived from the mesocrystals

Risk of Primary Liver Cancer Associated with Gallstones and Cholecystectomy: A Meta-Analysis

<div><p>Background</p><p>Recent epidemiological evidence points to an association between gallstones or cholecystectomy and the incidence risk of liver cancer, but the results are inconsistent. We present a meta-analysis of observational studies to explore this association.</p><p>Methods</p><p>We identified studies by a literature search of PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and relevant conference proceedings up to March 2014. A random-effects model was used to generate pooled multivariable adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Between-study heterogeneity was assessed using Cochran’s Q statistic and the <i>I².</i></p><p>Results</p><p>Fifteen studies (five case-control and 10 cohort studies) were included in this analysis. There were 4,487,662 subjects in total, 17,945 diagnoses of liver cancer, 328,420 exposed to gallstones, and 884,507 exposed to cholecystectomy. Pooled results indicated a significant increased risk of liver cancer in patients with a history of gallstones (OR = 2.54; 95% CI, 1.71–3.79; <i>n</i> = 11 studies), as well as cholecystectomy (OR = 1.62; 95% CI, 1.29–2.02; <i>n</i> = 12 studies), but there was considerable heterogeneity among these studies. The effects estimates did not vary markedly when stratified by gender, study design, study region, and study quality. The multivariate meta-regression analysis suggested that study region and study quality appeared to explain the heterogeneity observed in the cholecystectomy analysis.</p><p>Conclusions</p><p>Our results suggest that individuals with a history of gallstones and cholecystectomy may have an increased risk of liver cancer.</p></div

Characteristics of included studies on the association of gallstones, cholecystectomy and risk of liver cancer.

<p>Abbreviations: PB, population based; HB, hospital based; LC, liver cancer; CI, confidence interval; QS: quality score; NR, not report.</p>♯<p>Shanghai Women’sHealth Study (SWHS) (1996–2010).</p>§<p>Shanghai Men’s Health Study (SMHS) (2002–2010).</p><p>Adjustment factors: 1 age, 2 BMI, 3 education, 4 smoking status, 5 alcohol consumption, 6 family history of liver cancer, 7 history of diabetes, 8 history of hepatitis/chronic liver disease, 9 physical activity, 10 total energy intake, 11, income, 12 menopausal status, 13 calendar years, 14 gender, 15 race, 16 non-steroidal anti-inflammatory drugs intake, 17 perlipidemia, 18 hepatitis B virus infection, 19 hepatitis C virus infection, 20 cirrhosis, 21 time of diagnosis, 22, chronic pancreatitis, 23 study center, 24 year of interview, 25 study period, 26 geographic region, 27, state buy-in status.</p><p>Characteristics of included studies on the association of gallstones, cholecystectomy and risk of liver cancer.</p

Forest plot of the association between cholecystectomy and risk of liver cancer.

<p>Forest plot of the association between cholecystectomy and risk of liver cancer.</p

Flow chart depicts the selection of eligible studies.

<p>Flow chart depicts the selection of eligible studies.</p

Association analysis of HIF-2a gene polymorphisms between HBV-related patients and healthy controls in Zhuang nationality population.

<p>Association analysis of HIF-2a gene polymorphisms between HBV-related patients and healthy controls in Zhuang nationality population.</p

Association analysis of HIF-2a gene polymorphisms between HBV-related patients and healthy controls.

<p>Association analysis of HIF-2a gene polymorphisms between HBV-related patients and healthy controls.</p

Comparison of genotype and allele frequencies in the control subjects of our study and those from the HapMap Project.

<p>Comparison of genotype and allele frequencies in the control subjects of our study and those from the HapMap Project.</p