Metal organic frameworks as a catalyst for oxygen reduction: an unexpected outcome of a highly active Mn-MOF-based catalyst incorporated in activated carbon.

Owing to their unique chemistry and physical properties, metal-organic frameworks (MOFs) are an interesting class of materials which can be utilized for a wide array of applications. MOFs have been proposed to be used as catalysts for fuel cells, but their low intrinsic electronic conductivity hampered their utilization as is. In this work, we present the synthesis and application of MOF-based precious-metal-group-free (PGM-free) catalysts for oxygen reduction based on a unique metal-organic framework-carbon composite material. Benzene tricarboxylic acid-based MOFs were synthesized inside activated carbon (AC) with four different, first row transition metals: Mn, Fe, Co, and Cu. The MOFs@AC were analyzed electrochemically to measure their catalytic activity. Further physical and chemical characterization studies are performed to measure the material properties. The MOFs@AC are found to be conductive and active catalysts for the oxygen reduction reaction in an alkaline environment. Surprisingly, the Mn-MOF-based@AC exhibits the best performance with an onset potential of 0.9 V vs. RHE and the almost four-electron mechanism, as opposed to most other known PGM-free catalysts, which show Fe and Co as the most active metals.

Mapping and validation of a major QTL affecting resistance to pancreas disease (salmonid alphavirus) in Atlantic salmon (Salmo salar).

Pancreas disease (PD), caused by a salmonid alphavirus (SAV), has a large negative economic and animal welfare impact on Atlantic salmon aquaculture. Evidence for genetic variation in host resistance to this disease has been reported, suggesting that selective breeding may potentially form an important component of disease control. The aim of this study was to explore the genetic architecture of resistance to PD, using survival data collected from two unrelated populations of Atlantic salmon; one challenged with SAV as fry in freshwater (POP 1) and one challenged with SAV as post-smolts in sea water (POP 2). Analyses of the binary survival data revealed a moderate-to-high heritability for host resistance to PD in both populations (fry POP 1 h(2)~0.5; post-smolt POP 2 h(2)~0.4). Subsets of both populations were genotyped for single nucleotide polymorphism markers, and six putative resistance quantitative trait loci (QTL) were identified. One of these QTL was mapped to the same location on chromosome 3 in both populations, reaching chromosome-wide significance in both the sire- and dam-based analyses in POP 1, and genome-wide significance in a combined analysis in POP 2. This independently verified QTL explains a significant proportion of host genetic variation in resistance to PD in both populations, suggesting a common underlying mechanism for genetic resistance across lifecycle stages. Markers associated with this QTL are being incorporated into selective breeding programs to improve PD resistance.

Dual ectopic thyroid gland with Graves' disease and unilateral ophthalmopathy: a case report and review of the literature.

Ectopic thyroid gland (ETG) is a rare entity and can be seen anywhere in the route of descending gland. It is much rarer when encountered away from the midline. Dual ETG is such a rare entity that only a few have been reported in the literature. ETGs not only cause thyroid dysfunction, most commonly hypothyroidism and rarely hyperthyroidism, but also frequent local symptoms. Therapeutic options change according to patients' co-morbid diseases, age, size of goiter and presence of local symptoms. Graves' disease is very rarely detected in a patient with ectopic thyroid. There is no report in literature concerning ectopic thyroid presenting with Graves' disease and unilateral ophthalmopathy. We describe a case with dual ETG and Graves' disease and unilateral ophthalmopathy: it is the first reported in literature.

Influence of polyethylene glycol and povidone on the polymorphic transformation and solubility of carbamazepine.

PURPOSE: Influence of polymers on the polymorphic transition of drugs has received limited attention in the literature. The main objective of this study was to gain an understanding of the influence of polyethylene glycol and povidone on the crystalline modification and subsequently the solubility of carbamazepine in solid dispersions. METHODS: The physical state of the drug within the dispersions was determined using DSC and powder X-ray diffractometer. DSC and optical microscopy was used to study the kinetics and morphology of dihydrate formation, respectively. RESULTS: Both the polymeric dispersions showed an improved dissolution profile for carbamazepine. Carbamazepine was present in an amorphous form within the povidone dispersions. In contrast, the PEG dispersions showed the presence of crystalline drug. Higher ratios of drug/PEG resulted in the metastable form I of carbamazepine. Dihydrate formation from both the polymeric dispersions was higher compared with pure carbamazepine. The physical state of the drug and the amount of drug in solution accounted for the higher dihydrate formation from these dispersions. CONCLUSIONS: Knowledge of the factors contributing to enhanced solubility is critical to the stability of solid dispersions. Additionally, influence of polymers like povidone on the crystalline transitions of polymorphic drugs may be crucial during its use as a binder in granulation.

Influence of various drugs on the glass transition temperature of poly(vinylpyrrolidone): a thermodynamic and spectroscopic investigation.

PURPOSE: To determine the influence of hydrogen bonding and solubility parameter on the glass transition temperature (T(g)) of various drug-poly(vinylpyrrolidone) blends. METHODS: The T(g) of PVP films containing either acetaminophen, naproxen, salicylamide, carbamazepine, griseofulvin or propranolol hydrochloride were measured using differential scanning calorimetry. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction was used to characterize the specific interactions between the drug-PVP blends and the physical state of the films, respectively. The total solubility parameter and its individual components were calculated using the method of Van Krevelen. RESULTS: Salicylamide displayed the greatest plasticizing effect, depressing the T(g) to the minimum. This was consistent with the FTIR data, which indicated the presence of hydrogen bonding with PVP. Griseofulvin showed the least plasticizing effect due to lack of interaction with PVP. All the drugs except griseofulvin were amorphous within the film up to 30% (w/w) drug composition. The correlation between the various components of the solubility parameters and the plasticizing effect of drugs was very poor. CONCLUSIONS: Spectroscopic investigation for the presence of interaction between the drugs and PVP proved to be extremely predictive of the plasticizing effect of various drugs. In contrast, solubility parameters appeared to be far less sensitive indicators of drug-PVP miscibility.

Level of energy intake affects the estrous cycle in Sundevall's jird (Meriones crassus).

Effects of energy intake on the estrous cycle of the desert gerbillid, Sundevall's jird (Meriones crassus; 80 g; n=22) were studied. Females were offered either maintenance or below maintenance levels of millet seeds and ad lib. Atriplex halimus leaves and stems; drinking water was not available. Vaginal smears were used to determine sexual stage. We hypothesized that the estrous cycle ceases at low levels of energy intake and commences when sufficient energy is available. Females lost body mass linearly with a decrease in metabolizable energy intake. Estrous cycle averaged 4.46 d at maintenance energy intake but increased to an average of 7.81 d at 70% of maintenance energy intake. A cessation of the cycle occurred at an energy intake below 70% of maintenance requirements, which resulted in a body mass loss of more than 1% per day. More variability in the length of the different stages of the cycle was found with lower levels of energy intake. When offered ad lib. millet seeds and A. halimus (n=14), recovery to the normal cycle was attained within 10 d by 43% of the females and within 16 d by the rest of the females. Recovery time was longest in females that previously had the lowest energy intake. We concluded that the estrous cycle of M. crassus is sensitive to energy intake. With restricted energy intake, the estrous cycle and reproductive activities cease but can be restored with provision of adequate energy. This strategy ensures that reproduction occurs when conditions of food availability and body condition of the females are favorable.

The erythrocyte glutathione levels during oral glucose tolerance test.

Erythrocytes glutathione (GSH) levels were measured in erythrocytes from 33 subjects, at baseline and after 2-hour glucose loading in order to investigate the effect of glucose ingestion on the erythrocyte GSH. According to the World Health Organisation criteria 18 subjects had normal glucose tolerance (NGT)(mean age 48 +/- 10 years, 10 women, 8 men), 15 subjects had impaired glucose tolerance (IGT)(mean age 52 +/- 8 years, 9 women, 6 men). After 12-hour fasting, erythrocyte GSH levels were 40.5 +/- 8.06 and 39.27 +/- 10.26 mg/dl hemolisate in subjects with NGT and IGT, respectively (p = N.S). After 2-hour glucose loading, erythrocyte GSH levels decreased to 36.01 +/- 9.4 (p < 0.05) and 32.36 +/- 5.7 (p < 0.005) in subjects with NGT and IGT, respectively. The decrease in erythrocyte GSH levels in subjects with IGT was greater than in NGT individuals (p < 0.001). There was negative correlation between glucose, insulin, C-peptide, and erythrocyte GSH levels after glucose loading (p < 0.005). Our results suggest that glucose loading induce an oxidative stress in all subjects but this oxidative stress is greater in subjects with IGT than with NGT.