Insulin resistance and essential hypertension in Vietnamese subjects

Several epidemiological and experimental studies suggest that essential arterial hypertension is associated with hyperinsulinism and insulin resistance in obese subjects and also in subjects with normal body weight. Undernutrition remains frequent in adult Vietnamese people and mean body mass index is around 18.5 kg/m2 in Vietnam. The aim of this study was to look for insulin resistance in hypertensive Vietnamese subjects, despite a markedly lower BMI in Vietnam than in occidental countries. One hundred and eight hypertensive patients (51 men and 57 women) over 40 years (mean = 65.4 years) were compared with 36 healthy subjects (23 men and 13 women) over 40 years (mean = 63.8 years). Hypertensive patients had significantly higher BMI (20.5 +/- 0.3 (SEM) kg/m2 vs 18.4 +/- 0.4 kg/m2; p < 0.01), thicker triceps skinfold (1.26 +/- 0.07 cm vs 0.71 +/- 0.07 cm; p < 0.001) and not significantly different waist/hip ratio (0.88 +/- 0.01 vs 0.85 +/- 0.01). Blood glucose at fasting and 2 hours after 75 g glucose taken orally were similar in hypertensive and normotensive subjects. Plasma insulin at fasting and 2 hours after glucose were significantly higher in hypertensive patients (44.4 +/- 5.1 pmol/L vs 21.6 +/- 3.2 pmol/L; p < 0.05 and 271.1 +/- 21.6 pmol/L vs 139.1 +/- 15.2 pmol/L; p < 0.001). Thus, despite under-nutrition, hypertensive Vietnamese patients have a moderate but significant increase in BMI and fat mass without predominant abdominal localization, and a state of insulin-resistance, compared with normotensive healthy subjects.     

Facile synthesis of ZnBi<Subscript>2</Subscript>O<Subscript>4</Subscript>-graphite composites as highly active visible-light photocatalyst for the mineralization of rhodamine B

Novel highly active visible-light photocatalysts in the form of zinc bismuth oxide (ZnBi₂O₄) and graphite hybrid composites were prepared by coupling via a co-precipitation method followed by calcination at 450 °C. The as-prepared ZnBi₂O₄-graphite hybrid composites were tested for the degradation of rhodamine B (RhB) solutions under visible-light irradiation. The existence of strong electronic coupling between the two components within the ZnBi₂O₄-graphite heterostructure suppressed the photogenerated recombination of electrons and holes to a remarkable extent. The prepared composite exhibited excellent photocatalytic activity, leading to more than 93% of RhB degradation at an initial concentration of 50mg·L^-1 with 1.0 g catalyst per liter in 150min. The excellent visible-light photocatalytic mineralization of ZnBi₂O₄-1.0graphite in comparison with pristine ZnBi₂O₄ could be attributed to synergetic effects, charge transfer between ZnBi₂O₄ and graphite, and the separation efficiency of the photogenerated electrons and holes. The photo-induced h+ and the superoxide anion were the major active species responsible for the photodegradation process. The results demonstrate the feasibility of ZnBi₂O₄-1.0graphite as a potential heterogeneous photocatalyst for environmental remediation.     

MarCHGen: A framework for generating a malware concept hierarchy

Automatic classification of virus instances into a concept hierarchy has been attracting much attention from malware research community. However, it is definitely not a trivial work, because malwares usually come in binary forms whose actions are complicated and obfuscated. Therefore, the typical data mining approaches based on feature extraction are not easily applied. In this paper, we tackle this problem by introducing a framework known as MarCHGen (Malware Concept Hierarchy Generation). In this framework, we first apply virus logical concept analysis, which incorporates formal concept analysis with temporal logic to capture malware behaviours and generalize a virus concept lattice accordingly. Second, we propose an on‐the‐fly conceptual clustering technique to generate a malware concept hierarchy. In the MarCHGen framework, the malware concept hierarchy will be monitored by the prelarge data set management technique to avoid reclustering several times unnecessarily. Our approach has been applied in a real data set of virus, and promising experimental results have been acquired.     

Performance Analysis of Smart Relaying with Equal Gain Combining

Relaying communications has been proposed as a way to provide spatial diversity. In general, one is interested in a relaying system that can achieve the maximal diversity order with a low system complexity. One enabling technique is equal gain combining (EGC) and its application in relaying systems is the main focus of this paper. In particular, the techniques of EGC and smart relaying are combined in the decode-and-forward (DF) processing method. It is shown that for a system with one relay and M-ary phase-shift-keying (M-PSK) modulation, maximal diversity orders of 2m and 2 are achieved over Nakagami-m and Hoyt fading environments, respectively. With K relays, simulation results suggest that the corresponding diversity orders are m(K?+?1) and (K?+?1).     

Radio resource management for downlink multimedia services in TDMA/CDMA interference-limited cellular networks

This paper addresses the radio resource management (RRM) structure and efficient dynamic capacity allocation techniques for hybrid TDMA/ CDMA mobile cellular networks to support downlink multimedia services with different quality-of-service (QoS) requirements in an interference-limited environment. Various burst-driven timeslot-code assignment algorithms suitable for distributed processing are proposed to achieve high system capacity in terms of b/s/Hz/cell while maintaining a required percentage of satisfied users. Simulation results for various traffic scenarios are used for performance evaluation and comparison. The impacts of bursty WWW traffic on speech performance are also examined. It is shown that interference information can be used in timeslot-code assignment to significantly improve the system performance. Based on the received interference information, the minimum instantaneous power (MIP) algorithm aims to assign timeslot-codes that minimize the required transmitted power to maintain a target SINR. The MIP can provide an increase of 23% in system capacity. By considering to reduce both potentially received and generated interference in timeslot-code assignment, the Minimum Sum of Path-loss Ratios (MS-PLR) algorithm can further offer an additional capacity increase of 24%.     

Multiple heat pulses during PCR extension enabling amplification of GC-rich sequences and reducing amplification bias

PCR amplification over GC-rich and/or long repetitive sequences is challenging because of thermo-stable structures resulting from incomplete denaturation, reannealing, and self-annealing of target sequences. These structures block the DNA polymerase during the extension step, leading to formation of incomplete extension products and favoring amplification of nonspecific products rather than specific ones. We have introduced multiple heat pulses in the extension step of a PCR cycling protocol to temporarily destabilize such blocking structures, in order to enhance DNA polymerase extension over GC-rich sequences. With this novel type of protocol, we were able to amplify all expansions of CGG repeats in five Fragile X cell lines, as well as extremely GC-rich nonrepetitive segments of the GNAQ and GP1BB genes. The longest Fragile X expansion contained 940 CGG repeats, corresponding to about 2.8 kilo bases of 100% GC content. For the GNAQ and GP1BB genes, different length PCR products in the range of 700 bases to 2 kilobases could be amplified without addition of cosolvents. As this technique improves the balance of amplification efficiencies between GC-rich target sequences of different length, we were able to amplify all of the allelic expansions even in the presence of the unexpanded allele.     

Automatic summary assessment for intelligent tutoring systems

Summary writing is an important part of many English Language Examinations. As grading students’ summary writings is a very time-consuming task, computer-assisted assessment will help teachers carry out the grading more effectively. Several techniques such as latent semantic analysis (LSA), n-gram co-occurrence and BLEU have been proposed to support automatic evaluation of summaries. However, their performance is not satisfactory for assessing summary writings. To improve the performance, this paper proposes an ensemble approach that integrates LSA and n-gram co-occurrence. As a result, the proposed ensemble approach is able to achieve high accuracy and improve the performance quite substantially compared with current techniques. A summary assessment system based on the proposed approach has also been developed.     

Simulation of instrumented indentation and material characterization

Extensive large deformation finite element analyses were carried out to investigate the response of elasto-plastic materials obeying power law strain-hardening during the loading and unloading process of instrumented sharp indentation. The functional forms of the relationships between the characteristics of the load–indentation curve and the material properties of elasto-plastic materials were examined. The governing equations relating the curvature of the loading curve to the elasto-plastic material properties were formulated based on cavity expansion analogy. Two simple and robust algorithms were proposed for forward and reverse analyses. The numerical results obtained are in good agreement with published values. The uniqueness of the results from the reverse analysis algorithm was also addressed. By considering the load–displacement curve of Al 6061-T651, it was demonstrated that a one-to-one relationship between the elasto-plastic material properties and the load–displacement curve does not always exist.     

Multidisciplinary design optimization of a vehicle system in a scalable, high performance computing environment

Multidisciplinary Design Optimization of a vehicle system for safety, NVH (noise, vibration and harshness) and weight, in a scalable HPC environment, is addressed. High performance computing, utilizing several hundred processors in conjunction with approximation methods, formal MDO strategies and engineering judgement are effectively used to obtain superior design solutions with significantly reduced elapsed computing times. The increased computational complexity in this MDO work is due to addressing multiple safety modes including frontal crash, offset crash, side impact and roof crush, in addition to the NVH discipline, all with detailed, high fidelity models and analysis tools. The reduction in large-scale MDO solution times through HPC is significant in that it now makes it possible for such technologies to impact the vehicle design cycle and improve the engineering productivity.