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Background/objectives: Recent metabolomics technique reveals a plasma-free amino acid (PFAA)-based metabolite signature that is suggestive of altered PFAAs being an early manifestation of obesity-related insulin resistance. However, the PFAA profiles within non-obese, but more insulin-resistant Asians are not well researched. Compared with Caucasians, Asian populations have more central adiposity, which is generally regarded as metabolically more adverse, but the underlying mechanisms remain unclear. In the present study, we examined whether PFAA profiling was at least one important factor mediating central adiposity and insulin resistance, and aid in cardiovascular risk assessment in healthy Asians with normal body weight.Subject/methods: This was a cross-sectional study. A total of 190 healthy men (n=87 with a mean±s.d. body mass index (BMI) of 23.5±3.5 kg/m2) and women (n=103 with a mean±s.d. BMI of 21.4±3.7 kg/m2) residing in Singapore took part in this study. PFAA levels were measured by using an amino acid analyzer. Basic anthropometric measurements, fasting blood glucose, fasting serum insulin and lipid profiles were obtained using standard protocols.Results: Seven out of 18 amino acids were significantly correlated with measures of obesity (for example, waist circumference; waist-to-hip ratio and BMI) in current participants. Among them, the plasma concentrations of five amino acids, including Phe, Tyr, Met, Ala and His were positively associated with waist-to-hip ratio. With the exception of His, which had no association with insulin resistance, Phe, Tyr, Met and Ala were significantly associated with hyperinsulinemia and insulin resistance (P<0.05). In contrast, no associations were observed between circulating BCAAs (that is, Val, Leu, Ile), measures of obesity and insulin resistance. However, significant inverse associations were observed between BCAAs and total cholesterol and high-density lipoprotein.Conclusions: We found that central adiposity was associated with alterations of specific amino acids. As a result, PFAAs may serve as metabolite predictors of hyperglycemia, hyperinsulinemia and dyslipidemia in healthy participants. [ABSTRACT FROM AUTHOR]

A backward prediction model (BPM) has been developed to generate the missing bridge condition ratings in past years, thereby ensuring adequate condition data as required in long-term performance modelling. The BPM establishes a correlation between the known condition ratings and the non-bridge factors, including climate condition, traffic volume and population growth. The aim of this study is to confirm the ability of BPM in improving the prediction accuracy using the existing bridge deterioration models. The prediction accuracies of typical deterministic and stochastic bridge deterioration models are compared when different sets of BPM-generated historical condition ratings are used as input. Comparisons indicate that the prediction error decreases as more historical condition ratings are made available. Notwithstanding the above findings, several limitations of the current deterministic and stochastic bridge deterioration models are also worth noting and further research is essential to improve the prediction accuracy of bridge deterioration modelling. [ABSTRACT FROM AUTHOR]

A simple numerical modelling technique is proposed for estimating the shear-lag behaviour of framed-tube systems with multiple internal tubes. The system is analysed using an orthotropic box beam analogy approach in which each tube is individually modelled by a box beam that accounts for the flexural and shear deformations, as well as the shear-lag effects. The method idealises the tube(s)-in-tube structure as a system of equivalent multiple tubes, each composed of four equivalent orthotropic plate capable of carrying loads and shear forces. The numerical analysis so developed is based on the minimum potential energy principle in conjunction with the variational approach. The shear-lag phenomenon of such structures is studied taking into account the additional bending stresses in the tubes. Structural parameters governing the shear-lag behaviour in tube(s)-in-tube structures are also investigated through a series of numerical examples. [ABSTRACT FROM AUTHOR]

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Coarse and fine aggregates generated from crushed concrete products for new concrete can be generally accepted only when the properties of recycled aggregate concrete, in addition to the relationships between different properties of such a concrete, are well understood. The results of an experimental investigation into the relationship of compressive strength to ultrasonic pulse velocity and to rebound number is presented in this paper. It has been observed that for the water-cured concrete the strength-pulse velocity relationship is influenced by the use of the recycled aggregate. For the same value of the pulse velocity, the strength of recycled aggregate concrete is higher than that for the natural aggregate concrete. On the other hand, the strength-rebound number relationship is not affected by the aggregate type used. The combined method of pulse velocity and rebound number for strength estimation is also evaluated. [ABSTRACT FROM AUTHOR]