An algorithmic approach for system decomposition and balanced realized model reduction

This paper deals with the development of an algorithm for unstable continuous/discrete-time system decomposition into completely stable and completely unstable subsystems using real Schur transformation technique. The application of the proposed algorithm is investigated for unstable LTI plant or controller reduction and the available balanced realized model reduction theories applicable for stable systems are extended for unstable, continuous/discrete-time systems. The algorithm and its applications are illustrated with MATLAB-based computer-simulated results for continuous and discrete-time systems.     

Developing a community of thinking: assessment of environmental education

This paper discusses an oral assessment intervention in environmental education at two tertiary institutions in South Africa. A qualitative study grounded in a social constructivist framework, the inquiry locates learning and assessment of environmental education based on practical activities and first‐hand experience within the framework of situated learning, and explores processes of constructing and assessing knowledge within the learner's community of practice. The paper focuses on how communities of practice can be used as a possible learning approach in environmental education to address the diversity and challenges of classrooms, and on the efficacy of oral assessments structured to encourage thinking through dialog in such settings.     

Microalbuminuria in Obese Young and Middle Aged Population: A Potential Marker of Cardiovascular Risk

Microalbuminuria is an established cardiovascular risk indicator in diabetes, hypertension and the general population. There is lack of information on MAU in healthy obese Indian adults and an ongoing debate whether obese adults deserve targeted identification and clinical intervention for MAU and prediabetes. We aimed to screen the healthy obese, young (group I) and middle aged (group II) adults for prevalence of MAU and prediabetes and study its association with Framingham risk score. The study included 50 healthy obese young (20–30 years) and middle aged adults (31–50 years), attending the outpatient clinic of Dept. of Medicine for a duration of 2 months (July–August). The patients were screened for fasting blood sugar, lipid profile and MAU. Of the total patients 28 % had MAU, 32.14 % of which had prediabetes and 33.33 % had diabetes whereas 10 % were normoglycemic. The group I patients had 50 % cases of MAU and group II had 25 % patients with MAU. Group II 63.63 % pre-diabetics. The values of MAU obtained were correlated with age, gender, body mass index, systolic and diastolic blood pressure, FBS, waist to hip ratio using Pearson’s Coefficient (p < 0.05). The 10 year CVD risk calculated using FRS in subjects with MAU was higher as compared to those without MAU. Thus we conclude that Indian, young and middle aged obese adults to be at a risk of prediabetes, MAU and CV risk warranting their routine screening for better clinical outcomes.     

UV-B Induced stimulation of phosphatidylinositol 3-kinase in human fetal hepatocytes

We investigated the effect of UV-B irradiation on PI 3-kinase activity in human fetal hepatocytes. When cells were exposed to monochromatic (304nm) UV-B light, a significant increase in intracellular PI 3-kinase activity was observed in a dose dependent manner with maximal activity upon 1500 Jm⁻² irradiation. At 1500 Jm⁻² dose PI 3-kinse activity increased by 80% in membrane fraction of fetal hepatocytes of 25 weeks gestation. PI 3-kinse inhibitors wortmannin and LY294002 specifically inhibited the UV-B induced lipid kinase activity and blocked significantly the UV-B induced cell viability. The data suggests a correlation between cell survival and elevated levels of PI 3-kinase and suggest that UV-B irradiation at a dose of 1500 Jm⁻² is ideal for fetal hepatocyte transplantation. Also, PI 3-kinase levels could be a representative marker for viable UV-B irradiated fetal hepatocytes for transplantation.     

A study on interaction of Aluminium with rat intestinal brush border membrane

The present studies with aluminium chloride given in drinking water showed marked inhibition in the activities of intestinal brush border membrane marker enzymes, namely alkaline phosphatase, acetyl cholinesterase, γ-glutamyl transpeptidase and sucrase. Moreover, a significant depression in the levels of membrane constituents, viz phospholipids, cholesterol, hexoses and sialic acid following aluminium chloride treatment was also observed. On the basis of these studies it may be concluded that if aluminium is taken in high quantities it may alter the structure and functioning of the intestinal brush border membrane, which in turn may lead to the improper digestion and reduced nutrient uptake from the small intestine.     

Clodronate-superparamagnetic iron oxide-containing liposomes attenuate renal injury in rats with severe acute pancreatitis

Background and objective

It has been shown that macrophages play an important role in the development of severe acute pancreatitis (SAP), and eventually lead to multiple organ failure (MOF). Clodronate-liposome selectively depleted macrophages. This study was to investigate the role of renal macrophage infiltration in acute renal injury in rats with SAP and to evaluate the potential of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance imaging (MRI) for diagnosis.

Methods

Superparamagnetic Fe₃O₄ nanoparticles were prepared by chemical coprecipitation. SPIO-liposomes and SPIO-clodronate-liposomes were prepared by the thin film method. SAP models were prepared by injection of sodium taurocholate into the subcapsular space of rat pancreas. Sprague-Dawley rats were randomly divided into a control group, SAP plus SPIO-liposome (P) group, and SAP plus SPIO-clodronate-containing liposome (T) group. Kidney injury was evaluated by T2-weighted MRI scan. The levels of serum amylase (SAM), blood urea nitrogen (BUN), and serum creatinine (SCr) were measured by an automated enzymatic method. Serum tumor necrosis factor-α (TNF-α) was measured by enzyme-linked immunosorbent assay (ELISA). Pathological changes in the pancreas and kidney were observed using hematoxylin and eosin (H&E) staining, while cell apoptosis was detected with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. In addition, the macrophage markers (CD68) of the renal tissue were detected with immunohistochemistry.

Results

The pathological changes in the pancreas and kidneys of rats in the T group were milder than those in the P group. The MRI signal intensity of the kidneys in the P and T groups was significantly lower than that in the control group. There were significant changes in the two experimental groups (P<0.01). The levels of SAM, Bun, SCr, and TNF-α in rats in the P group were higher than those in the control group (P<0.01) and in the T group (P<0.01). The apoptosis of the kidney in the T group was higher than that in the P group at 2 and 6 h (P<0.01).

Conclusions

Clodronate-containing liposomes protected against renal injury in SAP rats, and SPIO can be used as a tracer for MRI examination to detect renal injury in SAP rats. SPIO-aided MRI provided an efficient non-invasive way to monitor the migration of macrophages after renal injury in rats with SAP.     

反复张力下V形切口圆条的表面裂纹的疲劳扩展

研究目的：在相同的反复张力下,研究V形切口圆条表面裂纹的疲劳扩展规律。研究方法：1.构建V形切口圆条模型（图1）,基于线性二次元将模型表面离散成一个个网格点（图2）;2.以AZ-6A-T5镁合金为例,利用J积分计算应力强度因数,利用NASGRO裂纹增长率模拟裂纹的疲劳扩展;3.通过研究不同的裂纹纵横比和对应的应力强度因数之间的相关性来研究裂纹的扩展。重要结论：1.在裂纹扩展时裂纹纵横比的初始值对断裂形状的发展有重要影响;2.裂纹纵横比对疲劳负荷寿命的作用比缺口半径更加明显;3.当裂纹前缘演变成一条直线形时可观察到不稳定的裂纹扩展;4.裂纹深度一定时,断裂纵横比越小,疲劳负荷寿命越短;5.当裂纹纵横比为0.6-0.7时,出现了不稳定的裂纹扩展。     

Critical perspectives on testing teaching: reframing teacher education for English medium instruction

The investigation reported here provides a basis for considering the role of corrective and transformative critiques in producing knowledge through testing teaching for reframing teacher education in response to, and as an expression of, the globalisation of English. This knowledge-producing approach to critique begins with a literature review of prior testing models of content and language integrated learning through English medium instruction (EMI) programmes. Delphi procedures were employed with a panel of 30 experts from three focus groups, namely teachers, testing experts, and teacher evaluation administrators. A comparison of relative importance of the indicators generated through this study via the analytic hierarchy process yielded practical implications for reframing the internationalisation of education using EMI. The analysis of interviews with teachers was used to critically rework or otherwise correct the testing model. Through adopting the practice of critique as a knowledge-producing venture, this study offers a model of EMI testing that can contribute to improvements in the organisation of professional learning and change, as well as certification procedures.