Fine grained AZ31 produced by conventional thermo-mechanical processing

The magnesium alloy AZ31 was processed by severe hot rolling and annealing. This processing was optimised to produce recrystallised grain sizes as small as 2.2 μm. The texture of the processed plate was similar to that of the as-received material, with a strong basal alignment in the normal direction. Tensile testing of the fine grained material showed an increase in the strength and elongation compared to the as-received plate. It is  concluded that the improved mechanical properties of the fine grained material results from a refinement in the grain size and the elimination of shear bands that pre-exist in the as-received material.

Health implications of body size perception and weight tolerance in older adults

Obesity is a well-recognized risk factor for Type II diabetes and cardiovascular disease. In this study a high percentage of older adults were either overweight or obese. The aims were to assess older adults' tolerance for excess weight, and to compare self-perceptions of an acceptable weight with national guidelines. Participants were 76 males and females aged between 65 and 97 years. Results indicated that 60 per cent accurately identified their own body size. Further, participants were more tolerant of excess weight in males compared to females, regardless of age. It was concluded that this cohort remains vulnerable to weight-related illnesses.

Risk of cardiovascular and all-cause mortality in individuals with diabetes mellitus, impaired fasting glucose, and impaired glucose tolerance. The Australian Diabetes, Obesity and Lifestyle Study (AusDiab)

Background--Diabetes mellitus increases the risk of cardiovascular disease (CVD) and all-cause mortality. The relationship between milder elevations of blood glucose and mortality is less clear. This study investigated whether impaired fasting glucose and impaired glucose tolerance, as well as diabetes mellitus, increase the risk of all-cause and CVD mortality.

Methods and Results--In 1999 to 2000, glucose tolerance status was determined in 10 428 participants of the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab). After a median follow-up of 5.2 years, 298 deaths occurred (88 CVD deaths). Compared with those with normal glucose tolerance, the adjusted all-cause mortality hazard ratios (HRs) and 95% confidence intervals (CIs) for known diabetes mellitus and newly diagnosed diabetes mellitus were 2.3 (1.6 to 3.2) and 1.3 (0.9 to 2.0), respectively. The risk of death was also increased in those with impaired fasting glucose (HR 1.6, 95% CI 1.0 to 2.4) and impaired glucose tolerance (HR 1.5, 95% CI 1.1 to 2.0). Sixty-five percent of all those who died of CVD had known diabetes mellitus, newly diagnosed diabetes mellitus, impaired fasting glucose, or impaired glucose tolerance at baseline. Known diabetes mellitus (HR 2.6, 95% CI 1.4 to 4.7) and impaired fasting glucose (HR 2.5, 95% CI 1.2 to 5.1) were independent predictors for CVD mortality after adjustment for age, sex, and other traditional CVD risk factors, but impaired glucose tolerance was not (HR 1.2, 95% CI 0.7 to 2.2).

Conclusions--This study emphasizes the strong association between abnormal glucose metabolism and mortality, and it suggests that this condition contributes to a large number of CVD deaths in the general population. CVD prevention may be warranted in people with all categories of abnormal glucose metabolism.

Differences in height explain gender differences in the response to the oral glucose tolerance test - the AusDiab study

Aim To determine the extent of gender-related differences in the prevalence of glucose intolerance for the Australian population and whether body size may explain such differences.

Methods Cross-sectional data were collected from a national cohort of 11 247 Australians aged ≥ 25 years. Glucose tolerance status was assessed according to both fasting plasma glucose (FPG) and 2-h plasma glucose (2hPG) levels following a 75-g oral glucose tolerance test (OGTT). Anthropometric and glycated haemoglobin measurements were also made.

Results Undiagnosed diabetes and non-diabetic glucose abnormalities were more prevalent among men than women when based only on the FPG results (diabetes: men 2.2%, women 1.6%, P = 0.02; impaired fasting glycaemia: men 12.3%, women 6.6%, P < 0.001). In contrast 16.0% of women and 13.0% of men had a 2hPG abnormality (either diabetes or impaired glucose tolerance, P = 0.14). Women had a mean FPG 0.3 mmol/l lower than men (P < 0.001), but 2hPG 0.3 mmol/l higher (P = 0.002) and FPG-2hPG increment 0.5 mmol/l greater (P < 0.001). The gender difference in mean 2hPG and FPG-2hPG increment disappeared following adjustment for height. For both genders, those in the shortest height quartile had 2hPG levels 0.5 mmol/l higher than the tallest quartile, but height showed almost no relationship with the FPG.

Conclusions Men and women had different glycaemic profiles; women had higher mean 2hPG levels, despite lower fasting levels. It appeared that the higher 2hPG levels for women related to lesser height and may be a consequence of using a fixed glucose load in the OGTT, irrespective of body size.

Gender differences in the prevalence of impaired fasting glycaemia and impaired glucose tolerance in Mauritius. Does sex matter?

Objective: To examine gender differences in the characteristics and prevalence of various categories of glucose tolerance in a population study in Mauritius.

Research design and methods: In 1998, a community-based cross-sectional survey was conducted in Mauritius. Categories of glucose metabolism were determined in 5388 adults, with an oral glucose tolerance test given to those who did not have previously diagnosed diabetes (n = 4036). Other cardiovascular risk factors were assessed among those without known diabetes.

Results: For men and women the prevalence of diabetes (22.0 vs. 21.8%, respectively) and the prevalence of coexisting impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) (3.2 vs. 2.9%) were similar. However, men were twice as likely as women to have isolated IFG [5.1% (4.2–6.0) vs. 2.9% (2.3–3.5)], despite being younger, thinner and with lower plasma insulin but higher lipids. Conversely, the prevalence of isolated IGT was lower in men [9.0% (7.9–10.2) vs. 13.9% (12.6–15.1)]. Among non-diabetic individuals, fasting glucose was higher in men than women, whereas 2-h glucose was higher in women. In people without diabetes, women had significantly higher body mass index, beta cell function (HOMA-B), fasting and 2-h insulin than men and significantly lower waist-hip ratios, waist circumference, insulin sensitivity (HOMA-S) and triglycerides.

Conclusion: In Mauritius, the distribution of impaired glucose metabolism differs by sex. The observation that IFG is more prevalent in men and IGT more prevalent in women raises important questions about their underlying aetiology and the ability of the current glucose thresholds to equally identify men and women at high-risk of developing diabetes. IFG should be seen as a complimentary category of abnormal glucose tolerance, rather than a replacement for IGT.

Green tea, black tea, and epigallocatechin modify body composition, improve glucose tolerance, and differentially alter metabolic gene expression in rats fed a high-fat diet

The mechanisms of how tea and epigallocatechin-3-gallate (EGCG) lower body fat are not completely understood. This study investigated long-term administration of green tea (GT), black tea (BT), or isolated EGCG (1 mg/kg per day) on body composition, glucose tolerance, and gene expression related to energy metabolism and lipid homeostasis; it was hypothesized that all treatments would improve the indicators of metabolic syndrome. Rats were fed a 15% fat diet for 6 months from 4 weeks of age and were supplied GT, BT, EGCG, or water. GT and BT reduced body fat, whereas GT and EGCG increased lean mass. At 16 weeks GT, BT, and EGCG improved glucose tolerance. In the liver, GT and BT increased the expression of genes involved in fatty acid synthesis (SREBP-1c, FAS, MCD, ACC) and oxidation (PPAR-α, CPT-1, ACO); however, EGCG had no effect. In perirenal fat, genes that mediate adipocyte differentiation were suppressed by GT (Pref-1, C/EBP-β, and PPAR-γ) and BT (C/EBP-β), while decreasing LPL, HSL, and UCP-2 expression; EGCG increased expression of UCP-2 and PPAR-γ genes. Liver triacylglycerol content was unchanged. The results suggest that GT and BT suppressed adipocyte differentiation and fatty acid uptake into adipose tissue, while increasing fat synthesis and oxidation by the liver, without inducing hepatic fat accumulation. In contrast, EGCG increased markers of thermogenesis and differentiation in adipose tissue, while having no effect on liver or muscle tissues at this dose. These results show novel and separate mechanisms by which tea and EGCG may improve glucose tolerance and support a role for these compounds in obesity prevention.

Identification and characterization of genes conferring salt tolerance to Escherichia coli from pond water metagenome

Metagenomics provides culture-independent access to gene pool of the whole microbial communities. To identify genes responsible for salt tolerance in unculturable bacteria, Escherichia coli clones were enriched with an ability to grow at inhibitory NaCl concentrations (750 mM) from a pond water metagenomic library. From two unique clones, genes encoding for proteins with similarity to a putative general stress protein (GspM) harbouring GsiB domain and a putative enoyl-CoA hydratase (EchM) were identified to be responsible for salt tolerance. The gspM was expressed by its native promoter whereas the echM was expressed from the lacZ promoter of the plasmid. EchM was overexpressed with a hexahistidyl tag. Purified EchM showed crotonyl-CoA hydratase activity. These genes have potential application in generating salt tolerant recombinant bacteria or transgenic plants.

Repair and tolerance of DNA damage in higher plants

DNA repair mechanisms constitute an essential cellular response to DNA damage arising either from metabolic processes or from environmental sources such as ultraviolet radiation. Repair of these lesions may be via direct reversal, or by processes such as nucleotide excision repair (NER), a coordinated pathway in which lesions and the surrounding nucleotides are excised and replaced via DNA resynthesis. The importance of repair is illustrated by human disease states such as xeroderma pigmentosum and Cockayne's syndrome which result from defects in the NER system arising from mutations in XP- genes or XP- and CS- genes respectively Little detail is known of DNA damage repair processes in plants, despite the economic and ecological importance of these organisms. This study aimed to expand our knowledge of the process of NER in plants, largely via a polymerase chain reaction (PCR)-based approach involving amplification, cloning and characterisation of plant genomic DNA and cDNA. Homologues of the NER components XPF/RAD1 and XPD/RAD3 were isolated as both genomic and complete cDNA sequences from the model dicotyledonous plant Arabidopsis thaliana. The sequence of the 3'-untranslated region of atXPD was also determined. Comparison of genomic and cDNA sequences allowed a detailed analysis of gene structures, including details of intron/exon processing. Variable transcript processing to produce three distinct transcripts was found in the case of atXPF. In an attempt to validate the proposed homologous function of these cDNAs, assays to test complementation of resistance to ultraviolet radiation in the relevant yeast mutants were performed. Despite extensive amino acid sequence conservation, neither plant cDNA was able to restore UV-resistance. As the yeast RAD3 gene product is also involved in vivo in transcription, and so is required for viability, the atXPD cDNA was tested in a complementation assay for this function in an appropriate yeast mutant. The plant cDNA was found to substantially increase the viability of the yeast mutant. The structural and functional significance of these results is discussed comparatively with reference to yeast, human and other known homologues. Other putative NER homologues were identified in A. thaliana database sequences, including those of ERCC1/RAD10 and XPG/ERCC5/RAD2, and are now the subjects of ongoing investigations. This study also describes preliminary investigations of putative REVS and RAD30 translesion synthesis genes from A. thaliana.

VVP808 is a novel agent that improves glucose tolerance in DIO mice

As the prevalence of diabetes mellitus continues to increase, there is an urgent need to discover new, effective treatment strategies to combat this disorder. In this study, we tested a novel agent, VVP808, which we previously demonstrated has insulin-sensitising properties (as measured by an increase in insulin-stimulated glucose uptake in 3T3-L1 adipocytes). A dose-ranging study was performed (10-100mg/kg/d) in C57BL/6J mice that had been fed a high-fat diet (45% of energy) for 12 weeks. VVP808 was administered by single daily oral gavage for a period of 16 days. Body weight, food intake and water intake were measured daily, whilst fasting blood glucose and plasma insulin levels were measured at the beginning and end of the study, with an intra-peritoneal glucose tolerance test (ipGTT) performed on day -1 and day 13. Administration of VVP808 to diet-induced obese (DIO) mice caused a strong dose-dependent improvement in glucose tolerance. There was a 34-42% reduction in the blood glucose area under the curve (AUC) at doses of 20mg/kg, 50mg/kg and 100mg/kg VVP808 (p=0.02-0.005). Administration of VVP808 resulted in a small but significant reduction in body weight in the 50mg/kg and 100mg/kg treated animals relative to vehicle (p=0.01 and 0.001 respectively). This decrease in body weight was associated with a reduction in food intake for the 100mg/kg treated animals only. Epididymal fat pad weight was significantly reduced in animals treated with 100mg/kg VVP808 (p=0.01). Furthermore, treatment with VVP808 for 16 days resulted in a highly significant dose-dependent reduction in fasting blood glucose levels relative to vehicle treated animals (p= 0.01-0.001). In conclusion, our data showed that VVP808 acts in a dose-dependent manner to reduce fasting blood glucose levels and improve glucose tolerance. These data suggest that VVP808 is an interesting new agent with potential for development as a novel therapeutic for type 2 diabetes.

Thermo-mechanical processing and the shape memory effect in an Fe–Mn–Si-based shape memory alloy

The effect of cold rolling and annealing on the shape memory effect (SME) in an Fe–Mn–Si-based alloy has been studied. It has been found
that the SME in these alloys can be significantly increased by the appropriate thermo-mechanical processing (TMP). The optimum conditions
were found to be 15% cold rolling followed by annealing at 800 ◦C for 15 min. This produced a total strain recovery of 4.5%. TEM showed that
this processing schedule produces a microstructure of evenly spaced, and well defined stacking faults throughout the parent phase. It is shown for
the first time that samples processed in this way produce a larger fraction of martensite compared to samples in the as-austenitized condition. It
is concluded that the stacking faults induced by TMP act as nucleation sites for martensite formation during deformation. The SME is improved
primarily as a result of the increased amount of martensite that is formed in this condition.

The study into fault tolerance based on rollback-recovery for clusters

The provision of fault tolerance is an important aspect to the success of distributed and cluster computing. Through this research , a transparent, autonomic and efficient fault tolerant facility was designed and implemented; thereby relieving the burden of a user having to handle and react to the failure of an application.

Tolerance of larger body sizes by young adults living in Australia and Hawaii

Identifying the barriers to achieving an appropriate body size is important for health. This study investigated young adults' tolerance of excess weight in other adults. Participants were 172 students (65 male, 107 female) with a mean age of 22.24 years (SD = 1.61). Half the participants resided in Australia, and half in Hawaii. Students from both countries were found to be tolerant of body sizes larger than those recommended for good health. These results help inform our understanding of the factors that may influence weight gain, and have important implications for the worldwide obesity problem and related health issues.