Analysis of the structure and luminescence properties of Zn2GeO4:Eu3+ according to Judd–Ofelt theory

The preparation and characteristic of nanorod-like Zn₂GeO₄ doped with Eu³⁺ or zinc germanate (ZGO):xEu³⁺ (x = 0 ÷ 0.05), which was synthesized using the hydrothermal method, are described. The influence of Eu³⁺-doping ions on the structure and the optical properties of ZGO was also investigated. According to the photoluminescence spectra, ZGO:xEu³⁺ nanophosphors gave a red emission due to the ⁵D₀→⁷F₂ emission of Eu³⁺ ions. In accordance with Judd–Ofelt theory, the intensity parameters for f–f transitions from the emission and absorption spectrum were determined. At the ⁵D₀ excited state of Eu³⁺, total spontaneous emission probabilities (A_R), lifetimes (τ_R), branching ratios (β_R), and quantum efficiency (η) were calculated. The ZGO:xEu³⁺ (x = 0.02, 0.03, 0.04) phosphor showed the branch ratio β (⁵D₀→⁷F₂) > 60%, indicating that the phosphors prepared here have a promising potential as laser light. The sample with a concentration of 0.04Eu³⁺ achieved the highest quantum efficiency of 84%, suggesting that it has potential light-emitting diode applications.     

Synbiotics: a New Route of Self-production and Applications to Human and Animal Health

Probiotics and Antimicrobial Proteins - Synbiotics are preparations in which prebiotics are added to probiotics to achieve superior performance and benefits on the host. A new route of their...     

Hypolipidaemic Effects of (24R)-4α-methyl-5α-stigmasta-7,22-dien-3β-ol Derived from Aurantiochytrium mangrovei BT3 in the HEPG2 Cell Line

Applied Biochemistry and Microbiology - Aurantiochytrium mangrovei BT3, a heterotrophic marine microalga, has the ability to produce high amounts of polyunsaturated fatty acids and bioactive...     

Undiagnosed Cryptic Diversity in Small,Microendemic Frogs (Leptolalax) from the Central Highlands of Vietnam

A major obstacle in prioritizing species or habitats for conservation is the degree of unrecognized diversity hidden within complexes of morphologically similar, “cryptic” species. Given that amphibians are one of the most threatened groups of organisms on the planet, our inability to diagnose their true diversity is likely to have significant conservation consequences. This is particularly true in areas undergoing rapid deforestation, such as Southeast Asia. The Southeast Asian genus Leptolalax is a group of small-bodied, morphologically conserved frogs that inhabit the forest-floor. We examined a particularly small-bodied and morphologically conserved subset, the Leptolalax applebyi group, using a combination of molecular, morphometric, and acoustic data to identify previously unknown diversity within. In order to predict the geographic distribution of the group, estimate the effects of habitat loss and assess the degree of habitat protection, we used our locality data to perform ecological niche modelling using MaxEnt. Molecular (mtDNA and nuDNA), acoustic and subtle morphometric differences revealed a significant underestimation of diversity in the L. applebyi group; at least two-thirds of the diversity may be unrecognised. Patterns of diversification and microendemism in the group appear driven by limited dispersal, likely due to their small body size, with several lineages restricted to watershed basins. The L. applebyi group is predicted to have historically occurred over a large area of the Central Highlands of Vietnam, a considerable portion of which has already been deforested. Less than a quarter of the remaining forest predicted to be suitable for the group falls within current protected areas. The predicted distribution of the L. applebyi group extends into unsurveyed watershed basins, each potentially containing unsampled diversity, some of which may have already been lost due to deforestation. Current estimates of amphibian diversity based on morphology alone are misleading, and accurate alpha taxonomy is essential to accurately prioritize conservation efforts.     

Patient Satisfaction with Methadone Maintenance Treatment in Vietnam: A Comparison of Different Integrative-Service Delivery Models

Background

Patient satisfaction is an important component of quality in healthcare delivery. To inform the expansion of Methadone Maintenance Treatment (MMT) services in Vietnam, we examined the satisfaction of patients with regards to different services delivery models and identified its associated factors.

Methods

We interviewed 1,016 MMT patients at 5 clinics in Hanoi and Nam Dinh province. The modified SATIS instrument, a 10-item scale, was used to measure three dimensions: “Services quality and convenience”, “Health workers’ capacity and responsiveness” and “Inter-professional care”.

Results

The average score was high across three SATIS dimensions. However, only one third of patients completely satisfied with general health services and treatment outcomes. Older age, higher education, having any problem in self-care and anxiety/depression were negatively associated with patient’s satisfaction. Meanwhile, patients receiving MMT at clinics, where more comprehensive HIV and general health care services were available, were more likely to report a complete satisfaction.

Conclusion

Patients were highly satisfied with MMT services in Vietnam. However, treatment for drug users should go beyond methadone maintenance to address complicated health demands of drug users. Integrating MMT with comprehensive HIV and general health services together with improving the capacity of health workers and efficiency of services organisation to provide interconnected health care for drug users are critical for improving the outcomes of the MMT program.     

Liraglutide Improves Hypertension and Metabolic Perturbation in a Rat Model of Polycystic Ovarian Syndrome

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder in women of reproductive age, with a prevalence of 5–8%. Type 2 diabetes and cardiovascular disease (CVD) are its long-term complications. Targeted therapies addressing both these complications together are lacking. Glucagon like peptide-1 (GLP-1) agonists that are used to treat type 2 diabetes mellitus have beneficial effects on the cardiovascular system. Hence we hypothesized that a GLP-1 agonist would improve both cardiovascular and metabolic outcomes in PCOS. To test this hypothesis, we used an established rat model of PCOS. Prepubertal female Sprague Dawley rats were sham-implanted or implanted s.c. with dihydrotestosterone (DHT) pellets (90 day release; 83μg/day). At 12 wks of age, sham implanted rats received saline injections and the DHT treated animals were administered either saline or liraglutide (0.2mg/kg s.c twice daily) for 4 weeks. Subgroups of rats were implanted with telemeters between 12-13 weeks of age to monitor blood pressure. DHT implanted rats had irregular estrus cycles and were significantly heavier than the control females at 12 weeks (mean± SEM 251.9±3.4 vs 216.8±3.4 respectively; p<0.05) and 4 weeks of treatment with liraglutide in DHT treated rats significantly decreased body weight (mean± SEM 294.75 ±3.2 in DHT+ saline vs 276.25±2.7 in DHT+ liraglutide group respectively; p<0.01). Liraglutide treatment in the DHT implanted rats significantly improved glucose excursion during oral glucose tolerance test (area under the curve: DHT+ saline 28674±310 vs 24990± 420 in DHT +liraglutide p <0.01). DHT rats were hypertensive and liraglutide treatment significantly improved mean arterial pressure. These results suggest that GLP-1 treatment could improve DHT–induced metabolic and blood pressure deficits associated with PCOS.     

Identification and genetic characterization of the Pseudomonas aeruginosaleuB gene encoding 3-isopropylmalate dehydrogenase

The Pseudomonas aeruginosa leuB gene, encoding 3-isopropylmalate dehydrogenase, was identified upstream of asd, encoding aspartate-β-semialdehyde dehydrogenase. Genetic analysis indicated that leuB is identical to the previously mapped gene defined by the leu-10 allele. The chromosomal leuB locus was inactivated by gene replacement. The insertions had no adverse effect on expression of the downstream asd gene but resulted in leucine auxotrophy. The leuB gene encodes a protein containing 360 amino acids (with a molecular weight of 39153), which was expressed in Escherichia coli as a M, 42000 protein. The results suggested that, in contrast to the situation in other bacteria (E. coli, Salmonella typhimurium and Bacillus subtilis) the P. aeruginosa leuB gene is physically separated from the genes encoding the other enzymes of the isopropylmalate pathway.     

Molecular basis for interaction between Icap1 alpha PTB domain and beta 1 integrin.

Icap1 alpha is a 200-amino acid protein that binds to the COOH-terminal 13 amino acids ((786)AVTTVVNPKYEGK(798)) of the integrin beta(1) subunit. Alanine scanning mutagenesis of this region revealed that Val(787), Val(790), and (792)NPKY(795) are critical for Icap1 alpha binding. The NPXY motif is a known binding substrate for phosphotyrosine binding (PTB) domain proteins. The sequences of Icap1 alpha, residues 58--200, and the beta(1) integrin, residues 786-797, were aligned to the available PTB-peptide structures to generate a high quality structural model. Site-directed mutagenesis showed that Leu(135), Ile(138), and Ile(139) of Icap1 alpha, residues predicted by the model to be in close proximity to (792)NPKY(795), and Leu(82) and Tyr(144), residues expected to form a hydrophobic pocket near Val(787), are required for the Icap1 alpha-beta(1) integrin interaction. These findings indicate that Icap1 alpha is a PTB domain protein, which recognizes the NPXY motif of beta(1) integrin. Furthermore, our date suggest that an interaction between Val(787) and the hydrophobic pocket created by Leu(82) and Tyr(144) of Icap1 alpha forms the basis for the specificity of Icap1 alpha for the beta(1) integrin subunit.     

Characterization of a Pseudomonas aeruginosa Fatty Acid Biosynthetic Gene Cluster: Purification of Acyl Carrier Protein (ACP) and Malonyl-Coenzyme A:ACP Transacylase (FabD)

A DNA fragment containing the Pseudomonas aeruginosa fabD (encoding malonyl-coenzyme A [CoA]:acyl carrier protein [ACP] transacylase), fabG (encoding beta-ketoacyl-ACP reductase), acpP (encoding ACP), and fabF (encoding beta-ketoacyl-ACP synthase II) genes was cloned and sequenced. This fab gene cluster is delimited by the plsX (encoding a poorly understood enzyme of phospholipid metabolism) and pabC (encoding 4-amino-4-deoxychorismate lyase) genes; the fabF and pabC genes seem to be translationally coupled. The fabH gene (encoding beta-ketoacyl-ACP synthase III), which in most gram-negative bacteria is located between plsX and fabD, is absent from this gene cluster. A chromosomal temperature-sensitive fabD mutant was obtained by site-directed mutagenesis that resulted in a W258Q change. A chromosomal fabF insertion mutant was generated, and the resulting mutant strain contained substantially reduced levels of cis-vaccenic acid. Multiple attempts aimed at disruption of the chromosomal fabG gene were unsuccessful. We purified FabD as a hexahistidine fusion protein (H6-FabD) and ACP in its native form via an ACP-intein-chitin binding domain fusion protein, using a novel expression and purification scheme that should be applicable to ACP from other bacteria. Matrix-assisted laser desorption-ionization spectroscopy, native polyacrylamide electrophoresis, and amino-terminal sequencing revealed that (i) most of the purified ACP was properly modified with its 4'-phosphopantetheine functional group, (ii) it was not acylated, and (iii) the amino-terminal methionine was removed. In an in vitro system, purified ACP functioned as acyl acceptor and H(6)-FabD exhibited malonyl-CoA:ACP transacylase activity.