bluuebunny/crossref_metadata_2025 huggingface dataset:
Are primary care practitioners in Barbados following diabetes guidelines? - a chart audit with comparison between public and private care sectors
Authors: Adams O Peter , Carter Anne O
Published: June 2011

Background

Over 19% of the population ≥ 40 years of age in Barbados are diabetic. The quality of diabetes primary care is uncertain.

Findings

Charts of diabetic and hypertensive patients were randomly sampled at all public and 20 private sector primary care clinics. Charts of all diabetic patients ≥ 40 years of age were then selected. Processes of care, and quality targets for blood pressure (BP), fasting blood glucose (FBG) and glycosylated haemoglobin (HbA1c) were documented.

252 charts of diabetic patients (125 public and 127 private) were audited. Patients had the following characteristics: mean age 64 years, female gender 61%, mean duration of diagnosis 9 years, and hypertension diagnosed 78%. Patients had an average of 4.7 clinic visits per year, 66% were prescribed metformin, 68% a sulphonylurea, 25% a statin, 21% insulin, 15% aspirin and 12% a glucosidase inhibitor. Public patients compared to private patients were more likely to be female (77% vs. 46%, p < 0.01); have a longer duration of diagnosis (11.4 vs. 6.6 years, p < 0.01), have more clinic visits per year (5.2 vs. 4.3, p < 0.01), and to be using insulin (28 vs. 15% p = 0.01). Over a 2 year period, the proportion of charts with the following recorded at least once was: BP 98%, weight 80%, FBG 76%, total cholesterol 72%, urine tested for albumin 66%, serum creatinine 62%, dietary advice 61%, exercise advice 49%, lipid profile 48%, foot examination 41%, HbA1c 33%, dietician referral 23%, retinal examination 18%, tobacco use 17%, body mass index 0%, and waist circumference 0%. Public patients were more likely to have recorded: weight (92% vs. 68%, p = < 0.01); tests for total cholesterol (78% vs. 65%, p = 0.02), albuminuria (72% vs. 59%, p = 0.03), serum creatinine (79% vs. 44%, p < 0.01), and foot examination (50% vs. 32%, p = < 0.01); dietician referral (37% vs. 8%, p < 0.01), and tobacco use (26% vs. 8%, p < 0.01). For those tested, the most recent BP was < 140/90 for 43%, HBA1c was < 7% for 28%, and FBG was < 6.7 mmol/L for 27%.

Conclusions

Interventions such as body mass assessment, lifestyle advice, screening for retinopathy, monitoring blood glucose control, and achieving BP and glycaemic targets need improvement.
Two logistic models for the prediction of hypothyroidism in pregnancy
Authors: Mbah Anthony U , Ejim Emmanuel C , Onodugo Obinna D , Ezugwu Francis O , Eze Matthew I , Nkwo Peter O , Ugbajah Winston C
Published: June 2011

Background

The mounting evidence linking hypothyroidism during pregnancy with poor pregnancy outcome underscores the need for screening and, therefore, a search for more reliable and cheaper screening methods.

Methods

The study was conducted in two phases. The phase one study comprised of healthy women in different stages of pregnancy who attended routine antenatal clinic at St Theresa's Maternity Hospital, Enugu, Nigeria from September 6 to October 18 1994. In this study the variables compared between the hypothyroid and non-hypothyroid pregnant women were maternal age, the number of the pregnancy or gravidity, gestational age, social class, body weight, height, the clinically assessed size of the thyroid gland, serum free thyroxin (FT4) and serum thyrotrophin (TSH). Based on the parameter differences between the two comparison groups of pregnant women two Logistic models, Model I and Model 11, were derived to differentiate the hypothyroid group from their non-hypothyroid counterparts. The two logistic models were then applied in a prospective validation study involving 197 pregnant women seen at presentation in Mother of Christ Specialist Hospital and Maternity, Ogui Road, Enugu from March 2002 to November 2007

Findings

The findings were that 82 (50.3%) of the 163 pregnant women had thyroid gland enlargement while 60 (36.8%) had hypothyroidism as defined by FT4 values below and/or TSH above their laboratory reference ranges. The pregnant subjects with hypothyroidism, compared with their non-hypothyroid counterparts, were characterized by a higher gravidity (p < 0.01), a higher body weight (p < 0.01), a higher goiter prevalence rate (p < 0.01) and a more advanced gestational age (p < 0.0001). A significant, positive correlation was also found between body weight and gestational age (r = 0.5; p < 0.01) At the cut-off point for Model l (fitted with gravidity, thyroid size and gestational age) it had a sensitivity of 100%, a specificity of 72.8% and an overall predictive accuracy of 82.9%; whereas for Model II (fitted with gravidity, thyroid size and body weight) the sensitivity was 100%, the specificity was 59.2% and the overall accuracy of discrimination was 74.8%. In the prospective validation study both models showed a sensitivity of 100% each with specificities of 85.5% for Model I and 76.2% for Model II.

Conclusion

It is concluded that logistic models fitting gravidity, thyroid gland size and gestational age or body weight are useful alternatives in screening for hypothyroidism during pregnancy. There is, however, a need for further independent confirmation of these findings.
Mature autologous dendritic cell vaccines in advanced non-small cell lung cancer: a phase I pilot study
Authors: Perroud Maurício W , Honma Helen N , Barbeiro Aristóteles S , Gilli Simone CO , Almeida Maria T , Vassallo José , Saad Sara TO , Zambon Lair
Published: June 2011

Background

Overall therapeutic outcomes of advanced non-small-cell lung cancer (NSCLC) are poor. The dendritic cell (DC) immunotherapy has been developed as a new strategy for the treatment of lung cancer. The purpose of this study was to evaluate the feasibility, safety and immunologic responses in use in mature, antigen-pulsed autologous DC vaccine in NSCLC patients.

Methods

Five HLA-A2 patients with inoperable stage III or IV NSCLC were selected to receive two doses of 5 × 107 DC cells administered subcutaneous and intravenously two times at two week intervals. The immunologic response, safety and tolerability to the vaccine were evaluated by the lymphoproliferation assay and clinical and laboratorial evolution, respectively.

Results

The dose of the vaccine has shown to be safe and well tolerated. The lymphoproliferation assay showed an improvement in the specific immune response after the immunization, with a significant response after the second dose (p = 0.005). This response was not long lasting and a tendency to reduction two weeks after the second dose of the vaccine was observed. Two patients had a survival almost twice greater than the expected average and were the only ones that expressed HER-2 and CEA together.

Conclusion

Despite the small sample size, the results on the immune response, safety and tolerability, combined with the results of other studies, are encouraging to the conduction of a large clinical trial with multiples doses in patients with early lung cancer who underwent surgical treatment.

Trial Registration

Current Controlled Trials: ISRCTN45563569
Anti-inflammatory activity of monogalactosyldiacylglycerol in human articular cartilage in vitro: activation of an anti-inflammatory cyclooxygenase-2 (COX-2) pathway
Authors: Ulivi Valentina , Lenti Manuela , Gentili Chiara , Marcolongo Gabriele , Cancedda Ranieri , Descalzi Cancedda Fiorella
Published: June 2011

Introduction

The mono- and digalactosyldiacylglycerol (MGDG and DGDG) galactolipids have been purified from the thermophilic blue-green alga Phormidium sp. ETS-05 that colonizes the therapeutic thermal mud of Abano Terme and Montegrotto Terme, Italy. Both compounds present a marked composition in polyunsaturated fatty acids, mainly omega-3. The therapeutic thermal mud is applied mainly to osteoarthritic cartilage patients. In the present study the effect of MGDG treatment on proteins and factors expressed by human articular cartilage cells in culture and on pathways activated in inflammatory conditions was studied.

Methods

Primary cultures of human articular chondrocytes were used at cell passage number 1 (P1). Cells were treated in serum-free medium with inflammatory cytokines in the presence and in the absence of MGDG. Western blot was performed on collected medium and on cell layers. At least three different experiments were performed on primary cultures. The quantitation of the MGDG effect was performed by densitometric scanning of Western blots. p38 Mitogen Activated Protein Kinase (p38) activation, Nuclear Factor-kappaB (NF-kB) activation and Prostaglandin E2 (PGE2) quantitation were performed by commercially available assays. Results are given as the mean values ± SD. All statistical analyses were performed using GraphPad software. The two-tailed Student's t -test was performed.

Results

We report that MGDG: 1) represses the expression of interleukin-6 (IL-6) and interleukin-8 (IL-8) induced by interleukin-1alpha (IL-1α) or IL-1α + tumor necrosis factor α (TNFα) interfering with the p38 and NF-kB pathways; 2) is not toxic for the cells and does not affect the cell phenotype; 3) strongly enhances COX-2 expression induced by IL-1α or IL-1α + TNFα; 4) represses mPGES expression induced by IL-1α and the synthesis of PGE2 and induces the synthesis of 15-deoxy-Δ 12,14-prostaglandin J2 (15ΔPGJ2). In addition, the COX-2 product 15ΔPGJ2 added to the cells: 1) strongly represses IL-6 and IL-8 induced by IL-1α; 2) represses mPGES expression induced by IL-1α and the synthesis of PGE2.

Conclusions

All together these data suggest that MGDG has an anti-inflammatory activity in human articular cartilage and possibly activates an anti-inflammatory loop triggered by COX-2 via 15ΔPGJ2 production, indicating a possible role of COX-2 in resolution of inflammation. The purified compound is a novel anti-inflammatory agent potentially active for human articular cartilage pathologies related to inflammation.
Epigallocatechin-3-gallate suppresses the global interleukin-1beta-induced inflammatory response in human chondrocytes
Authors: Akhtar Nahid , Haqqi Tariq M
Published: June 2011

Introduction

Epigallocatechin-3-gallate (EGCG) is a bioactive polyphenol of green tea and exerts potent anti-inflammatory effects by inhibiting signaling events and gene expression. Interleukin-1beta (IL-1β) is the principal cytokine linked to cartilage degradation in osteoarthritis (OA). The objective of this study was to evaluate the global effect of EGCG on IL-1β-induced expression of proteins associated with OA pathogenesis in human chondrocytes.

Methods

Primary OA chondrocytes were pretreated with EGCG (10 to 100 uM) and then stimulated with IL-1β (5 ng/ml) for 24 hours. Culture supernatants were incubated with cytokine antibody arrays and immunoreactive proteins (80 proteins) were visualized by enhanced chemiluminiscence. Effect of EGCG on IL-1β-induced expression of 18 selected genes was verified by Real time-PCR and effect on IL-6, IL-8 and tumor necrosis factor-alpha (TNF-α) production was determined using specific ELISAs. Western immunoblotting was used to analyze the effect of EGCG on the interleukin-1 receptor-associated kinase 1 (IRAK-1) and TNF receptor-associated factor 6 (TRAF-6) proteins in IL-1β-stimulated chondrocytes. The role of nuclear factor kappa-B (NF-κB) and mitogen activated protein kinases (MAPKs) in the regulation of selected genes and the mechanism involved in EGCG mediated modulation of these genes was determined by using specific inhibitors for NF- κB (MG132) and MAPKs (p38-MAPK, SB202190; JNK-MAPK, SP600125, ERK-MAPK, PD98059).

Results

Out of 80 proteins present on the array, constitutive expression of 14% proteins was altered by EGCG treatment. No significant stimulatory effect was observed on the proteins associated with cartilage anabolic response. Stimulation with IL-1β enhanced the expression of 29 proteins. Expression of all 29 proteins up-regulated by IL-1β was found to be suppressed by EGCG. EGCG also inhibited the expression of the signaling intermediate TRAF-6 at 50 and 100 uM concentrations (P < 0.05). Our results identified several new targets of EGCG, including epithelial neutrophil activating peptide-78 (ENA-78), granulocyte macrophage colony stimulation factor (GM-CSF), growth- related oncogene (GRO), GRO-α, IL-6, IL-8, monocyte chemotactic protein-1 (MCP-1), MCP-3, macrophage inflammatory protein-1beta (MIP-1β), granulocyte chemotactic protein-2 (GCP-2), MIP-3alpha, interferon-gamma-inducible protein-10 (IP-10), nucleosome assembly protein-2 (NAP-2) and leukemia inhibitory factor (LIF). The inhibitory effects of EGCG were mainly mediated by inhibiting the activation of NF-κB and c-Jun N-terminal Kinase (JNK)-MAPK in human chondrocytes.

Conclusions

Our results suggest that the potential of EGCG in OA treatment/prevention may be related to its ability to globally suppress the inflammatory response in human chondrocytes. These results identify additional new targets of EGCG and advocate that EGCG may be a potent chondroprotective agent in OA.
New rat models of iron sucrose-induced iron overload
Authors: Vu'o'ng Lê Bá , Khorsi-Cauet Hafida , Villegier Anne-Sophie , Bach Véronique , Gay-Quéheillard Jérôme
Published: June 2011

The majority of murine models of iron sucrose-induced iron overload were carried out in adult subjects. This cannot reflect the high risk of iron overload in children who have an increased need for iron. In this study, we developed four experimental iron overload models in young rats using iron sucrose and evaluated different markers of iron overload, tissue oxidative stress and inflammation as its consequences. Iron overload was observed in all iron-treated rats, as evidenced by significant increases in serum iron indices, expression of liver hepcidin gene and total tissue iron content compared with control rats. We also showed that total tissue iron content was mainly associated with the dose of iron whereas serum iron indices depended essentially on the duration of iron administration. However, no differences in tissue inflammatory and antioxidant parameters from controls were observed. Furthermore, only rats exposed to daily iron injection at a dose of 75 mg/kg body weight for one week revealed a significant increase in lipid peroxidation in iron-treated rats compared with their controls. The present results suggest a correlation between iron overload levels and the dose of iron, as well as the duration and frequency of iron injection and confirm that iron sucrose may not play a crucial role in inflammation and oxidative stress. This study provides important information about iron sucrose-induced iron overload in rats and may be useful for iron sucrose therapy for iron deficiency anemia as well as for the prevention and diagnosis of iron sucrose-induced iron overload in pediatric patients.
Genome-wide analysis reveals the active roles of keratinocytes in oral mucosal adaptive immune response
Authors: Wu Tong , Jia Lihua , Du Rui , Tao Xiaoan , Chen Jinou , Cheng Bin
Published: June 2011

To elucidate the roles of oral keratinocytes in the adaptive immune response of oral mucosa, global gene expression analysis was performed by microarray technique and integrating computational methods, including hierarchical clustering, biological process Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis, self-organizing maps (SOMs) and biological association network analysis (BAN). Raw data from microarray experiments were uploaded to the Gene Expression Omnibus Database, http://www.ncbi.nlm.nih.gov/geo/ (GEO accession GSE28035). We identified 666 differentially expressed genes in the early stage (48 h) and 993 in the late stage (96 h) of the oral mucosal adaptive immune response. The analysis revealed that oral keratinocytes exerted diverse biological functions in different stages of immune response. Specifically, in 48 h the differentially expressed genes encompassed an array of biological ontology associated with immune response, such as antigen processing and presentation, and positive regulation of T-cell-mediated cytotoxicity. Several pathways which have been reported to be critical in inflammation, including mitogen-activated protein kinase pathway, were activated. Furthermore, after BAN construction, some putative hub genes and networks such as interleukin-1 α and its subnetwork were recognized. Taken together, these results give substantial evidence to support the active roles of keratinocytes in the oral mucosal adaptive immune response.
Effects of berberine on human rheumatoid arthritis fibroblast-like synoviocytes
Authors: Wang Xiu-hua , Jiang Song-min , Sun Qing-wen
Published: June 2011

Activated rheumatoid arthritis fibroblast-like synoviocytes (RAFLSs) play an important role in the initiation and progression of rheumatoid arthritis (RA). Rapid proliferation and defective apoptosis of RAFLSs are two main mechanisms contributing to synovial hyperplasia. Berberine, the major constituent of Coptidis Rhizoma, has been widely used as an antitumor and anti-inflammation agent. Here we show that berberine significantly inhibited cell proliferation of serum-starved human RAFLSs in a dose-dependent manner. Cell cycle analysis of berberine-treated RAFLSs indicated a cell cycle arrest at the G0/G1 phase. The inhibitory effects of berberine correlated with an induction of cyclin-dependent kinase (CDK) inhibitors Cip1/p21 and Kip1/p27 and a reduction of CDK2, CDK4 and CDK6, and cyclins D1, D2 and E. Furthermore, an apoptosis assay showed that berberine treatment increased apoptotic death of RAFLSs, which was associated with an increased expression of proapoptotic protein Bax and decreased expression of antiapoptotic proteins Bcl-2 and Bcl-xl, disruption of mitochondrial membrane potential, and activation of caspase-3, caspase-9 and poly (ADP-ribose) polymerase. Taken together, these results demonstrate that berberine exerts antiproliferative effects against RAFLSs, likely through deregulation of numerous cell cycle and apoptosis regulators, thus having potential therapeutic implications in the treatment of RA.
Bifidobacterium longum supplementation improved high-fat-fed-induced metabolic syndrome and promoted intestinal Reg I gene expression
Authors: Chen Jin Jin , Wang Ren , Li Xiao-fang , Wang Rui-liang
Published: June 2011

Recent evidence suggests that intestinal Bifidobacterium species (spp.) positively correlates with improved insulin resistance and obesity, and this might be linked to metabolic inflammation. The expression of intestinal REG (regenerating) family proteins which are widely involved in inflammatory bowel disease and diabetes are still unknown in metabolic syndrome. Hence, we investigated the effects of Bifidobacterium longum (BIF) supplementation on metabolic parameters, intestinal function and expression of Reg family genes in a rat model of metabolic syndrome induced by a high-fat (HF) diet. We specifically increased the gut bifidobacterial content of HF-fed rats through BIF supplementation. Compared with the normal chow-fed control rats, HF feeding significantly reduced intestinal Bifidobacterium. As expected, BIF supplementation fed rats had totally restored quantities of Bifidobacterium. HF diet-fed rats showed significant increase in body weight, fat deposits, systolic blood pressure, fasting glucose, fasting triglycerides and reduced insulin sensitivity, while increases of intestinal Bifidobacterium did improve HF-diet-induced metabolic disorders. HF feeding led to significantly higher levels of the plasma lipopolysaccharide, interleukin-1 β and intestinal myeloperoxidase, as well as intestinal inflammatory activity index, while these parameters were normalized to the control levels in the HF + BIF-treated rats. The levels of RegI mRNA and protein in the HF + BIF group were significantly higher than the control and the HF groups. Increasing Bifidobacterium in the gut improved HF-fed-induced metabolic syndrome by reducing metabolic endotoxin concentrations and intestinal inflammation, as well as upgrading the expression of intestinal Reg I as a regulator of growth factor.
Optimization of Train Nose Shape for Reducing Micro-Pressure Wave Radiated from Tunnel Exit
Authors: Kikuchi K. , Iida M. , Fukuda T.
Published: June 2011

When a compression wave generated by a high-speed train entering a tunnel propagates through the tunnel and arrives at the tunnel exit, an impulsive pressure wave (micro-pressure wave) is radiated from the tunnel exit. Improving the train nose shape is one of the techniques for suppressing the micro-pressure wave. Furthermore, tunnel entrance hoods are required for long concrete slab tunnels in order to suppress the micro-pressure wave. The effect of the tunnel entrance hood on the compression wave generated by the train can be evaluated by means of a rapid computational scheme devised and validated experimentally by Howe et al. In this study, the optimal longitudinal distribution of the cross-sectional area of the train nose shape was determined by using the rapid computational scheme and a genetic algorithm. The effect of the nose shape optimization was confirmed through experiments using scale models.
Reactive Power Generation and Optimization during a Power System Fault in Wind Power Turbines Having a DFIG and Crowbar Circuit
Authors: Cheng Mengzeng , Cai Xu
Published: June 2011

For variable-speed constant-frequency (VSCF) wind power generation, a doubly fed induction generator (DFIG) equipped with a crowbar circuit is becoming more widely used in electrical transmission networks. This prevents potentially damaging over-voltage and/or over-current conditions in the DFIG during a power system fault. The response of a DFIG based wind turbine system to voltage dips at the point of common coupling is studied in this paper. A crowbar circuit can limit the surge current as well as protect the rotor side converter and DC-link capacitor. When the crowbar is cut in, the rotor side converter is disconnected from the rotor windings, which makes the DFIG behave as an asynchronous induction generator with high rotor impedance. It is suggested that use of a crowbar circuit can reduce the reactive power absorbed by the stator and also assist in voltage recovery of the grid by injecting reactive power into the grid. This paper analyzes the influence of the AC crowbar resistors or inductors on the reactive power consumption of the stator during grid voltage dips. In addition, the paper presents a current-limiting method to control the grid side converter and the rotor side converter, which provides reactive power to the grid and thus enhance the capability of low voltage ride-through (LVRT). In the simulation studies presented, AC crowbars with different resistor and inductor values are selected. The simulation results show that the stator reactive power absorption can be controlled, while the rotor side converter and grid side converter can be controlled to inject reactive power into the grid to enhance voltage restoration and fault recovery.
Design and Performance Evaluation of a Grid Connected Small Wind Energy Conversion System
Authors: Arifujjaman Md
Published: June 2011

The power conditioning system for grid connection of a Permanent Magnet Generator (PMG)-based small wind energy conversion system requires a rectifier, boost converter and a grid-tie inverter. Such system should be based on an appropriate control strategy to control the aerodynamic power during high wind speed, maximum power production, and maximum power flow to the grid at all operating conditions. This paper presents mathematical modeling and control strategy for the grid connected PMG-based small wind energy conversion system. Furling control and expected dynamics are adopted with the wind turbine for aerodynamic power control, while the optimum speed of the wind turbine is followed to ensure the maximum power production. A novel controller is derived from the optimum speed information that promises maximum power flow to the grid by controlling the boost converter output voltage and current through the duty cycle. It is found that the proposed modeling and control strategy is feasible and results are verified through simulation as well as laboratory experimentation.
On the Existence of Non-Convexities in the Design Space of Isolated Wind-Battery Systems
Authors: Roy Anindita , Kedare Shireesh B , Bandyopadhyay Santanu
Published: June 2011

A set of all feasible design options depicted graphically on a diagram with system design variables is known as the design space. For an isolated wind-battery system, the design space is depicted on a rotor diameter vs. generator rating diagram with battery bank size as a parameter. Design space representation enables the distinction between the feasible and infeasible combinations of design variables. It forms a basis to understand the inter-relation between different design variables outlining the tradeoffs in design. In certain cases, it is observed that the feasible solution set may lead to a non-convex design space. Non-convexities in the design space imply that intuitive selection or arbitrary over sizing of design parameter(s) may lead to non-compliance with respect to overall reliability requirement. Through an illustrative example, it is shown that the primary reasons leading to design space non-convexity are the uneven distribution of wind speed standard deviation in the time horizon, high overall system reliability requirement and the wind regime of the site under consideration. From a graph of system reliability vs. coefficient of variation of wind speed (COV), it is observed that non-convexity in design space is most likely to occur for particular combinations of system reliability requirement and COV of wind speed. This representation facilitates predicting the occurrence of non-convexity in the design envelope prior to detailed system design and optimization; thus providing valuable insight to the system designer and preventing a possible failure of performance and loss of investment.
Development of Statistical Model for Prediction of Occupational Noise Exposure to SDL Operators in Indian Underground Coal Mines
Authors: Pandey R. K. , Thote N. R. , Singh T. N.
Published: June 2011

The main aim of this paper is to assess present scenarios of occupational noise exposure of the operators of a popular category of SDL in Indian underground coal mines and to develop a statistical model for prediction of occupational noise exposure to the SDL operators using machine age as an independent variable. Eighty SDL machines were selected randomly from 18 different mines. Machines working hour were monitored and recorded for all 18 mines. Full shift noise dose (TWA) was measured for the operator of each machine. Regression analysis was performed to develop the statistical model. Validity of the model was verified. The subjects are exposed to occupational noise ranging from 74 to 100.4 dBA TWA. The operator's TWA increases with increase in machine age. A fifth order polynomial equation describes the relationship between machine age and TWA. In a validation study, it was found that the predictive model works in the field on similar machines. The SDL operators are exposed to occupational noise generated, which ranges from 74 to 100.4 dBA TWA. The TWA increases with increase in the machine age. There exists a non linear relation between the SDL age and the corresponding TWA. The predictive statistical model developed in this study works satisfactorily in the field, hence the same is recommended for selected class of SDL machines deployed in Indian underground coal mines.
Practical Advanced Design Considering Random Distribution of Initial Geometric Imperfections
Authors: Zhang Yaochun , Jin Lu , Shao Yongsong , Zhao Jinyou
Published: June 2011

Current advanced analysis and design of steel frames, allows for the most unfavorable combination of initial imperfections. In fact, however, the initial geometric imperfections and their combinations are all random distributions. Recognising this situation, the sway installation tolerances and bow imperfections of both columns and beams are all considered to be the randomly distributed and simulation analyses for imperfections are made using Monte Carlo sampling method in this paper. A large number of parametric studies on twelve-storey single-bay frames with random imperfections have been carried out using the finite element method. Results indicate that both lateral drift values and girder deflections of the frames are distributed normally in the probability statistics terms. The characteristic values of these variables based on many simulation analyses, are extremely close to the results obtained for ideal frames which have on initial imperfections, so that the effects of initial imperfections can be neglected in the advanced design for similar structures. Moreover, a practical advanced design method is proposed, in which the serviceability state of the structure is first investigated under the required characteristic load combinations, and then the ultimate strength capacity is checked under the fundamental load combinations.
Sensitivity Analysis of Site Response Effect on Stochastic Responses of Two-Span Beam
Authors: Mezouer Nourredine , Silhadi Kamel , Hadid Mohamed
Published: June 2011

In this paper, a numerical sensitivity analysis of the spatial variability of ground motions due to site response effect on the stochastic response of a two-span structure subjected to this phenomenon is presented. The site response effect is due to the difference in local soil conditions at different support points. The transfer functions of the soil profiles under each support are analytically formulated. Kanai-Tajimi spectrum parameters are estimated and expressed analytically from the soil profile model. The example structure is intentionally taken to be a simple one as to allow a comprehensive sensitivity analysis. Interesting results in term of mean maximum responses (displacement, bending moment and shear forces) obtained from the spatial variability of ground motion are given and compared to those induced by uniform excitation. Each component of the responses (pseudo static, dynamic and dynamo static) is differently influenced by the site response effect, it is therefore essential to incorporate this effect in the analysis of long span structures to be more realistic.
Plate Girder Bridge Strengthened with Multi-Stepwise Thermal Prestressing Method
Authors: Ahn J.H. , Jung C.Y. , Choi K.T. , Kim S.H.
Published: June 2011

The strengthening of a plate girder bridge with external prestressing tendons is a commonly used method of upgrading existing bridges. Indeed, it has been known to offer advantages such behaviors as increased elastic behaviors under higher loading, increased ultimate resistance, and reduced deflection under service loads. However, this method has notable disadvantages such as stress concentration at anchorages and inefficient live load-carrying capacity. The thermal prestressing method (TPSM) for steel bridges proposed in this study uses thermal expansion and contraction of a cover-plate to provide a combination with the prestress effects of an external prestressing tendon and the section enlargement benefits of the external bonding method.

In this study, the basic concepts of the proposed strengthening protocol using multi-stepwise TPSM are presented. The existence of the strengthening effect is well substantiated and the proposed analytical approach is also rigorously verified. The significant strengthening effects on a simply supported plate girder bridge are analyzed.
Analytical Model for Dynamic Tension in Overhead Power Transmission Lines Subject to Strong Wind
Authors: Wang Dahai , Li Jie , Xie Qiang
Published: June 2011

Dynamic tension in power transmission lines generated by wind-induced vibrations is a critical issue in the design of wind-resistant power transmission towers. Wind-induced vibrations in transmission lines exhibit nonlinear geometric characteristics Using the vibration equation for a continuous cable system, the dynamic tension generated in a transmissio0n line by along-wind loading was decomposed into the two components of static nonlinear effects dependent on the mean wind speed and dynamic linear effects caused by turbulent wind, in the equilibrium plane. The two modes that contribute most to the dynamic tension in a transmission line are the first out-of-plane mode and the first symmetric in-plane mode. This allows the dynamic cable equation to be decoupled, allowing the time- and frequency-domain solutions of the along-wind dynamic tension to be obtained. The effectiveness of this proposed method is demonstrated by a real transmission line and a comparison of the results with a nonlinear finite element analysis.
Seismic Response Analysis of Transmission Tower-Line System on a Heterogeneous Site to Multi-Component Spatial Ground Motions
Authors: Bai Feng-Long , Hao Hong , Bi Kai-Ming , Li Hong-Nan
Published: June 2011

This paper studies the nonlinear responses of a coupled transmission towerline system on a heterogeneous site subjected to multi-component spatially varying ground motions. The three-dimensional finite element model of the transmission tower-line system is established with consideration of the geometric nonlinearity of the transmission lines. The spatial variation of ground motions associated with the wave passage, coherency loss and local site effects are considered. The spatial ground motions on ground surface are derived by modelling the base rock motion propagating through the local soil sites. The base rock motions are assumed consisting of out-of-plane and in-plane waves and are simulated stochastically based on an empirical coherency loss function and the filtered Tajimi-Kanai power spectral density function. The effects of multi-component, spatial variations of ground motions and varying site conditions at multiple tower foundations on seismic response of the transmission tower-line system are analysed. The study reveals that for a reliable seismic response analysis and safe and economic seismic resistance design of transmission tower-line systems, the multi-support and multi-component earthquake excitations with consideration of the effects of local site conditions on ground motion spatial variations should be considered.
Reduced Stiffness Buckling Analysis of Aboveground Storage Tanks with Thickness Changes
Authors: Jaca Rossana C. , Godoy Luis A. , Croll James G.A.
Published: June 2011

The Reduced Stiffness Analysis (RSA) to compute lower bounds to buckling loads of shells has been employed by a number of researchers as a simple way to evaluate the buckling capacity of shells that display unstable behavior and imperfection-sensitivity. It allows the use of simple eigenvalue analysis, without having to perform incremental nonlinear analysis, and is based on the physical behavior of the shell which recognizes that a significant contribution to the stability of a shell under lateral pressure is provided by its membrane stiffness. Unstable post-critical behavior is associated with the loss of this stabilizing membrane contribution. Past use of the approach has been mainly restricted to cases of uniform shell thickness and uniform pressures in the circumferential direction, in which case analytical solutions are possible. Recent applications by the authors and other researchers have shown ways to compute the lower bounds using finite element analysis, for which a modified eigenvalue analysis is constructed by neglecting the membrane contributions to the matrix containing the initial stresses. This paper illustrates the application of the methodology to cases of pressure loaded shells with thickness changes in the meridional direction. A semi-analytical finite element code has been employed for the buckling analysis when uniform pressures act on aboveground steel tanks. The tanks are representative of those constructed for the oil industry, with diameter to thickness ratios of the order of 3000, and height to diameter ratios lower than one.
Closed-Form Optimum Liquid Column Vibration Absorber Parameters for Base-Excited Damped Structures
Authors: Shum K.M. , Kwok K.C.S. , Hitchcock P.A.
Published: June 2011

There have been significant development of techniques for determining optimum parameters of passive dampers and vibration absorbers, but most of the existing studies are limited to the case of an undamped primary structure. This paper aims to develop a first order approximation of the optimal liquid column vibration absorber (LCVA) parameters for suppressing the displacement response of a damped structure under white noise induced ground acceleration. The optimum parameters of a LCVA for the case of an undamped primary structure subjected to white noise induced ground acceleration are first derived and the results are then extended to the case where some damping exists in the primary structure by using a perturbation technique. The accuracy of the derived formulas is then verified through a comparison with the results obtained from numerical methods as well as the results of other studies found in the literature. Finally, a direct approach for determining the optimal head loss coefficient is presented in this study. It is demonstrated that the closed-form approach is capable of predicting the optimal liquid column vibration absorber parameters with reasonable accuracy for damped primary structure.
Interval Reliability Based Condition Assessment of Bridges
Authors: Karunananda P.A.K. , Ohga M. , Dissanayake P.B.R.
Published: June 2011

Recent research indicates that small changes in input parameters of reliability models significantly affect outcomes of reliability computations. This is a considerable concern especially in reliability based condition assessments of old bridges which have lower reliabilities. To overcome such errors of input parameters, structural reliability can be combined with interval analysis (i.e., interval reliability). This paper presents an interval reliability based condition assessment procedure of bridges. Interval reliability of a component is introduced when resistance and load behave as: (1) normal variables; (2) log normal variables. Similarly, interval reliabilities of other components can be estimated. Finally, system interval reliability is estimated. Bridge condition is assessed by comparing with the acceptable reliability of the bridge. A case study, a steel girder bridge, is selected, and its interval reliability indices are estimated for possible errors of statistical parameters. The obtained results are then compared with an existing method without considering interval reliability. Results indicate that there are significant variations in reliability when interval reliability is considered.
CFRP Flexural and Shear Strengthening Technique for RC Beams: Experimental and Numerical Research
Authors: Barros Joaquim A. O. , Costa Inês G. , Ventura-Gouveia A.
Published: June 2011

Near surface mounted (NSM) technique has proved to be a very effective technique for the flexural strengthening of RC beams. Due to the relatively small thickness of the concrete cover that several beams present, cutting the bottom arm of steel stirrups for the installation of NSM laminates might be a possible strategy, whose implications on the beam's load carrying capacity need to be assessed. When steel stirrups are cut, however, the shear resistance can be a concern. This also happens when a strengthening intervention is carried out to increase the flexural resistance of a beam, since in certain cases it is also necessary to increase the shear resistance in order to avoid the occurrence of brittle shear failure. The present work assesses the effectiveness of a technique that aims to increase both the flexural and shear resistance of RC beams that have the bottom arm of the steel stirrups cut for the application of NSM laminates. This assessment is performed by experimental and numerical research. The main results of the experimental program are presented and analyzed, and the innovative aspects of a constitutive model implemented in a computer program are described, being their virtues and deficiencies discussed.
Progress on Experimental and Numerical Research for Slat Noise in JAXA
Authors: Yamamoto Kazuomi , Imamura Taro , Yokokawa Yuzuru
Published: June 2011

This paper summarizes the progress on experimental and numerical research activity for better understanding slat noise in Japan Aerospace Exploration Agency (JAXA). A slat is a leading edge device which is used during take-off and landing of an aircraft to enhance its aerodynamic performance at low speed flight. However, this device is known to be one of the dominant noise sources, especially during the landing phase. To clarify the noise generation mechanism, both experimental and numerical researches are conducted at JAXA. Overall characteristic of slat noise is obtained through several wind tunnel experiments associated with aerodynamic measurements. Large scale computation using large-eddy simulation technique is also performed around the slat region to seek for the relevant unsteady features. Both experimental and numerical results indicate that the dominant noise source from the slat, which has broadband characteristics, is generated around the slat trailing edge.
Large Eddy Simulation of Supersonic Jet Noise from a Circular Nozzle
Authors: Gao J. H. , Li X. D.
Published: June 2011

An imperfectly expanded supersonic jet is simulated with large eddy simulation (LES) method. The full 3D filtered Navier-Stokes equations in cylindrical coordinates coupled with the standard Smagorinsky model are solved by a computational aeroacoustic method. The Dispersion-Relation-Preserving scheme is used for spatial discretization and the low dissipation low dispersion Runge-Kutta method in 2N storage form is utilized for time marching. A high order explicit spatial filter is applied to remove the grid oscillations. An adaptive artificial selective damping is used for shock capturing. The supersonic jet with Mach number 1.19 is simulated. The simultaneous and time average flow field is analyzed. The near filed noise spectra are presented and compared with the experimental data of Ponton et al. and with the numerical results of the present authors by unsteady Reynolds averaged Navier-Stokes (URANS) method. It is shown that the numerical results by LES method agree better with the experimental data than the results by URANS method.
The New Structuralism: Conceptual Mapping of Emerging Key Concepts in Theory and Praxis
Authors: Oxman Rivka
Published: June 2011

The New Structuralism focuses upon the potential of novel design processes to return architecture to its material sources. A theoretical research presents how the structuring, encoding, and fabricating of material systems are contributing to a new material practice which demands a theoretical foundation comprehensive enough to integrate emerging theories, methods and technologies in design. Selected research works supports shared geometrical, structural and manufacturing representations and processes relevant to The New Structuralism are selected and reviewed. DDNET (Digital Design NETwork) is proposed as a conceptual structure which attempts to relate the body of these findings with theoretical constructs such as key concepts, models, techniques, technologies and leading precedents associated with The New Structuralism.
Examination of the Designs by Auguste Perret Using Digitally-Enabled Forensic Techniques
Authors: Brown Andre , Webb Nicholas
Published: June 2011

This paper discusses how digitally-enabled techniques can be used to augment our understanding of a designer's work, particularly in relation to unbuilt or lost projects. In the first half of the twentieth century Auguste Perret gained international recognition for his buildings and we employ two of his unbuilt museums as the basis for illustration of the technique. Current knowledge of his unbuilt projects is based on surviving literature and incomplete illustrations. We show that the use of digitally-enabled techniques facilitates a fuller examination of the original material. Interpretation of material requires parallel studies into the architect, their influences and the context they operated within in order to extrapolate and fill gaps in an informed way. The construction of various digital representations enables a forensic analysis of the projects; consequently we can produce a richer set of information that can, in turn, enhance our analysis and understanding of an architect and their work, in this case, Perret.
Disappearance of stacking fault in colloidal crystals under gravity
Authors: Mori A.
Published: June 2011

After reviewing a previous work on the disappearance of a stacking fault in the hard-sphere (HS) system confined between the top and bottom flat walls under gravity, we present results of a Monte Carlo (MC) simulation of HSs confined between the top flat wall and the bottom square patterned wall under gravity. In MC simulations of HSs between flat walls we observed disappearance of an intrinsic stacking fault through the glide of the Shockley partial dislocation in fcc (001) stacking forced by the stress from a small simulation box. The artifact that the driving force for the fcc (001) growth was the stress from the simulation box has been circumvented; the stress realizing the fcc (001) stacking has been replaced by that from square pattern on the bottom wall. Defect disappearance has also been observed for the square patterned bottom wall case.
Heat transfer modeling of multilayer reactive foil
Authors: Liu R. , Guo S. , Qiu X. , Wang J.
Published: June 2011

Nanostructured reactive foils have attracted a great deal of interest recently due to their unique mechanical and thermal properties. Reactive thin foil can be used as a controllable, localized heating source for joining applications, which enable soldering and brazing of materials at room temperature. In this paper, multiphysics-based numerical simulations were performed to simulate reactive thin foils. The conductive heat transfer equation and mass diffusion equations were solved for 1D, 2D, and 3D cases. 1D simulation examined the effect of the chemical reaction rate on the flame speed; 2D simulation gave the detailed temperature and composition distribution in the bi-layers; and 3D simulation demonstrated the localized heating effect of reactive thin foils on a silicon wafer substrate.
Thermoplastic elastomers including ground tyre rubber in a thermoplastic matrix
Authors: Cañavate J. , Casas P. , Carrillo F. , Nogués F. , Colom X.
Published: June 2011

Disposal of end of life tyres is regulated in many countries. The enormous amount produced every year needs the research of new ways of recycling. A common practice previous to any treatment is the grinding of the tyres by specialized companies producing ground tyre rubber powder. Several attempts to include this powder in polymeric matrixes have been developed, mainly resulting in a lack of compatibility of the components. In this paper we propose a new composite including GTR and EPDM in a HDPE matrix. The use of peroxides to produce crosslinking produces a thermoelastomeric material suitable for industrial applications.