Organic Additives for the Enhancement of Laminar Flow in a Brain‐Vessels‐Like Microchannel Assembly

Organic polymers were extracted from okra, aloe vera, and hibiscus leaves and used as drag‐reducing additives (DRAs) to enhance the laminar flow in custom‐made microchannels that simulate the human brain vessels. The experiment was conducted using an open‐loop microfluidic system. The flow enhancement performance was evaluated as the function of percentage of flow increment of mucilage additives at different concentrations. Okra mucilage showed greater flow enhancement performance at higher mucilage concentration while both aloe vera and hibiscus mucilage performed better at lower additive concentration. The findings prove the potential of these organic polymers as DRAs to enhance the blood flow.     

Characterisation of a uranium ore using multiple X-ray diffraction based methods

Uranium bearing ores are often a complex mixture of minerals and compounds, a number of which are not of economic importance and are commonly referred to as gangue materials. In order to improve the efficiency of the dissolution stage of the overall uranium extraction process, a greater understanding of the minerals and compounds present in the ore is required. A greater knowledge of the gangue materials present is important as they can influence various aspects of the dissolution process such as providing potential adsorption sites for aqueous uranium species and through influencing the equilibrium of reactions involving aqueous uranium species. In this study the mineralogy of a uranium ore was investigated using a range of X-ray diffraction (XRD) based methods including in situ high temperature XRD and XRD using a synchrotron beam line. The results obtained from standard XRD (Cu Kα), high temperature XRD and synchrotron XRD (16.534 keV) were compared and a number of minerals were identified. The improved spatial resolution and intensity of the synchrotron data allowed for superior phase identification of a variety of minerals where standard X-ray techniques gave inconclusive results.     

Solution Structure and Constrained Molecular Dynamics Study of Vitamin B12 Conjugates of the Anorectic Peptide PYY(3–36)

Vitamin B₁₂–peptide conjugates have considerable therapeutic potential through improved pharmacokinetic and/or pharmacodynamic properties imparted on the peptide upon covalent attachment to vitamin B₁₂ (B₁₂). There remains a lack of structural studies investigating the effects of B₁₂ conjugation on peptide secondary structure. Determining the solution structure of a B₁₂–peptide conjugate or conjugates and measuring functions of the conjugate(s) at the target peptide receptor may offer considerable insight concerning the future design of fully optimized conjugates. This methodology is especially useful in tandem with constrained molecular dynamics (MD) studies, such that predictions may be made about conjugates not yet synthesized. Focusing on two B₁₂ conjugates of the anorectic peptide PYY(3–36), one of which was previously demonstrated to have improved food intake reduction compared with PYY(3–36), we performed NMR structural analyses and used the information to conduct MD simulations. The study provides rare structural insight into vitamin B₁₂ conjugates and validates the fact that B₁₂ can be conjugated to a peptide without markedly affecting peptide secondary structure.     

Hydroxyoctadecadienoic Acids Regulate Apoptosis in Human THP‐1 Cells in a PPARγ‐Dependent Manner

Macrophage apoptosis, a key process in atherogenesis, is regulated by oxidation products, including hydroxyoctadecadienoic acids (HODEs). These stable oxidation products of linoleic acid (LA) are abundant in atherosclerotic plaque and activate PPARγ and GPR132. We investigated the mechanisms through which HODEs regulate apoptosis. The effect of HODEs on THP‐1 monocytes and adherent THP‐1 cells were compared with other C18 fatty acids, LA and α‐linolenic acid (ALA). The number of cells was reduced within 24 hours following treatment with 9‐HODE (p < 0.01, 30 μM) and 13 HODE (p < 0.01, 30 μM), and the equivalent cell viability was also decreased (p < 0.001). Both 9‐HODE and 13‐HODE (but not LA or ALA) markedly increased caspase‐3/7 activity (p < 0.001) in both monocytes and adherent THP‐1 cells, with 9‐HODE the more potent. In addition, 9‐HODE and 13‐HODE both increased Annexin‐V labelling of cells (p < 0.001). There was no effect of LA, ALA, or the PPARγ agonist rosiglitazone (1μM), but the effect of HODEs was replicated with apoptosis‐inducer camptothecin (10μM). Only 9‐HODE increased DNA fragmentation. The pro‐apoptotic effect of HODEs was blocked by the caspase inhibitor DEVD‐CHO. The PPARγ antagonist T0070907 further increased apoptosis, suggestive of the PPARγ‐regulated apoptotic effects induced by 9‐HODE. The use of siRNA for GPR132 showed no evidence that the effect of HODEs was mediated through this receptor. 9‐HODE and 13‐HODE are potent—and specific—regulators of apoptosis in THP‐1 cells. Their action is PPARγ‐dependent and independent of GPR132. Further studies to identify the signalling pathways through which HODEs increase apoptosis in macrophages may reveal novel therapeutic targets for atherosclerosis.     

The process of Retirement Planning Scale (PRePS): Development and validation.

Although a substantial proportion of the western population is approaching retirement age, little is known about how they are preparing for the future. Much attention has been paid to the consumption of educational material and retirement wealth in the present literature, but the process of retirement planning has been ignored. S. L. Friedman and E. K. Scholnick's (1997) theoretical model provided the basis for a comprehensive measure of retirement planning. According to their process theory, individuals develop an understanding of the problem, set goals, make a decision to start preparing, and finally undertake the behaviors needed to fulfill their goals. Fifty-two items were developed to assess each stage of the planning process for financial, health, lifestyle, and psychosocial retirement planning. These were tested on a population sample of 1,449 New Zealanders aged 49–60. Confirmatory factor analysis, bivariate correlations, and hierarchical regression provided support for the valid use of the measure. Necessary antecedents, such as the tendency to look to the future, and locus of control were significantly related to the Process of Retirement Planning Scale (PRePS). The PRePS also outperformed retirement planning measures used in the Health and Retirement Study (F. T. Juster & R. Suzman, 1995) after controlling for socioeconomic and psychological variables. This measure will enable social policy makers to determine which stages of retirement planning require support and intervention. The PRePS will also help to determine which domains of retirement planning predict well-being in later life and the factors which differentiate those who are planning from those who are not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Silicon-doped hydroxyapatite prepared by a thermal technique for hard tissue engineering applications

Hydroxyapatite (HA, Ca₅(PO₄)₃OH) has been extensively used for bone implantation due to its similarity to the mineral component of bone, which makes it strongly osteoconductive. However, HA has low resorbability, and it is difficult to replace by a newly regenerated bone. Si doping can enhance the resorbability of HA by modifying its crystal structure. Here, we developed a simple thermal technique for preparing Si-doped HA from silica (SiO₂) and HA precursors, both of which are inexpensive and commercially available. This method included the physical binding of SiO₂ and HA particles, followed by pressing and sintering the mixture at an elevated temperature, which enhanced the atomic diffusion of Si into HA unit cells. We also evaluated the simulated body fluid (SBF) activity of the Si-doped HA prepared by this technique and showed that it significantly had higher resorbability and mineralizing potential compared to the pure HA. Our experimental design including, the individual precipitation and resorption assays enabled us to explain the mechanism behind the improved activity of Si-doped HA in SBF. This was attributed to the formation of new phases, such as β-tricalcium phosphate (β-TCP) and calcium silicate (Ca₂SiO₄) with higher solubility than HA on the SiO₂-contating HA during the sintering stage. This can provide some guidelines for designing new calcium phosphate-based materials for hard tissue engineering applications.     

Epidemiologic and economic analyses of pregnancy loss attributable to mastitis in primiparous Holstein cows

The main objective of the study reported here was to examine the association between pregnancy loss (PL) and previous exposure to clinical or subclinical mastitis before breeding or during gestation in primiparous Holstein cows. A secondary objective was to estimate the cost of clinical mastitis during gestation, including that of PL attributable to mastitis in study cows. A total of 687 primiparous Holstein cows from 1 dairy farm were included in a matched case-control study. Study cows were declared pregnant via ultrasound on d 33 after timed artificial insemination (TAI). Case cows (n = 78) were those diagnosed as nonpregnant by rectal palpation on d 47 or 75 after TAI. Control cows were those confirmed as pregnant by rectal palpation on d 47 and 75 after TAI. Case cows were matched with eligible controls according to year of calving and calving-to-conception interval ±3 d. Cows were assigned to 1 of 3 groups: (1) cows not affected with clinical or subclinical mastitis; (2) cows affected with subclinical mastitis (Dairy Herd Improvement Association somatic cell score >4.5); and (3) cows affected with clinical mastitis during 2 exposure periods, 1 to 42 d before breeding or during gestation (1 to PL diagnosis day for case cows, and 1 to 75 d for control cows). Conditional logistic regression was used to model the odds of PL as a function of previous exposure to mastitis in study cows. Mastitis before breeding was not associated with PL. The odds of PL were 2.21 times greater in cows affected with clinical mastitis during gestation (95% confidence interval = 1.01, 4.83), compared with cows without mastitis, after controlling for breeding type and lameness. The cost of clinical mastitis during gestation was $149, which includes the cost ($27) of PL attributable to mastitis. In conclusion, this study provides evidence that clinical mastitis during gestation can cause PL in primiparous dairy cows leading to economic losses.