bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of a survey methodology for gastroesophageal reflux disease in China
Authors: Cao Yang , Yan Xiaoyan , Ma Xiu-Qiang , Wang Rui , Johansson Saga , Wallander Mari-Ann , He Jia
Published: September 2008

Background

Gastroesophageal reflux disease (GERD) causes a wide range of clinical symptoms and potentially serious complications, but epidemiological data about GERD in China are limited. The aim of this pilot study was to develop and validate a methodology for the epidemiological study of GERD in China.

Methods

Regionally stratified, randomized samples of Shanghai residents (n = 919) completed Mandarin translations of the Reflux Disease Questionnaire (RDQ), GERD Impact Scale, Quality of Life in Reflux and Dyspepsia (QOLRAD) questionnaire and 36-item Short Form Health Survey (SF-36). Reliability and construct validity were tested by appropriate statistical analyses.

Results

The response rate was 86%. The test-retest reliability coefficients for the RDQ, GERD Impact Scale, QOLRAD and SF-36 were 0.80, 0.71, 0.93 and 0.96, respectively, and Cronbach's alpha coefficients were 0.86, 0.80, 0.98 and 0.90, respectively. Dimension scores were highly correlated with the total scores for the QOLRAD and SF-36, and factor analysis showed credible construct validity for the RDQ, GERD Impact Scale and SF-36. The RDQ GERD score was significantly negatively correlated with QOLRAD dimensions of food and drink problems and social functioning, and was significantly negatively correlated with all dimensions of the SF-36. All eight of the SF-36 dimensions were significantly correlated with the QOLRAD total score.

Conclusion

This study developed and tested a successful survey methodology for the investigation of GERD in China. The questionnaires used demonstrated credible reliability and construct validity, supporting their use in larger epidemiological surveys of GERD in China.
Association of ADAM33 gene polymorphisms with adult allergic asthma and rhinitis in a Chinese Han population
Authors: Su Dongju , Zhang Ximei , Sui Hong , Lü Fuzhen , Jin Lianhong , Zhang Jing
Published: September 2008

Background

Rhinitis and asthma are very common diseases involving genetic and environmental factors. Most patients with asthma also have rhinitis, which suggests the concept of 'one airway, one disease.' A disintegrin and metalloproteinase 33 (ADAM33) is the first asthma-susceptible gene to be discovered by positional cloning. To evaluate the potential influence of ADAM33 gene polymorphisms on allergic rhinitis (AR) and allergic asthma (AS), a case-control study was conducted on the Han population of northeast China.

Methods

Six polymorphic sites (V4, T+1, T2, T1, S1, and Q-1) were genotyped in 128 patients with AR, 181 patients with AS, and 151 healthy controls (CTR). Genotypes were determined by the polymerase chain restriction fragment length polymorphism (PCR-RFLP) method. Data were analyzed using the chi-square test with Haploview software.

Results

The single nucleotide polymorphisms (SNPs), V4 G/C, T+1 A/G, and T1 G/A, of the ADAM33 gene may be the causal variants in AR, whereas ADAM33 V4 G/C, T2 A/G, T1 G/A, and Q-1A/G may participate in the susceptibility of AS.

Conclusion

These results suggest that polymorphisms of the ADAM33 gene may modify individual susceptibility to AR and AS in a Chinese Han population.
Trypanosoma cruzi alkaline 2-DE: Optimization and application to comparative proteome analysis of flagellate life stages
Authors: Magalhães Adriana D , Charneau Sébastien , Paba Jaime , Guércio Rafael AP , Teixeira Antonio RL , Santana Jaime M , Sousa Marcelo V , Ricart Carlos AO
Published: September 2008

Background

Trypanosoma cruzi, a flagellate protozoan, is the etiological agent of Chagas disease, a chronic illness that causes irreversible damage to heart and digestive tract in humans. Previous 2-DE analyses of T. cruzi proteome have not focused on basic proteins, possibly because of inherent difficulties for optimizing 2-DE in the alkaline pH range. However, T. cruzi wide pH range 2-DE gels have shown few visible spots in the alkaline region, indicating that the parasite either did not have an appreciable amount of alkaline proteins or that these proteins were underrepresented in the 2-DE gels.

Results

Different IEF conditions using 6–11 pH gradient strips were tested for separation of T. cruzi alkaline proteins. The optimized methodology described here was performed using anodic "paper bridge" sample loading supplemented by increased concentration of DTT and Triton X-100 on Multiphor II (GE Healthcare) equipment and an electrode pad embedded in DTT- containing solution near the cathode in order to avoid depletion of reducing agent during IEF. Landmark proteins were identified by peptide mass fingerprinting allowing the production of an epimastigote 2-DE map. Most identified proteins corresponded to metabolic enzymes, especially those related to amino acid metabolism. The optimized 2-DE protocol was applied in combination with the "two-in-one gel" method to verify the relative expression of the identified proteins between samples from epimastigote and trypomastigote life stages.

Conclusion

High resolution 2-DE gels of T. cruzi life forms were achieved using the optimized methodology and a partial epimastigote alkaline 2-DE map was built. Among 700 protein spots detected, 422 were alkaline with a pI above 7.0. The "two-in-one gel" method simplified the comparative analysis between T. cruzi life stages since it minimized variations in spot migration and silver-stained spot volumes. The comparative data were in agreement with biological traits of T. cruzi life forms and also corroborated previous T. cruzi proteomic studies. For instance, enzymes related to amino acid metabolism and dehydrogenases were more abundant in epimastigote 2-DE gel whilst trans-sialidase and a paraflagellar protein were found specifically in the trypomastigote 2-DE profile.
Whole genome expression and biochemical correlates of extreme constitutional types defined in Ayurveda
Authors: Prasher Bhavana , Negi Sapna , Aggarwal Shilpi , Mandal Amit K , Sethi Tav P , Deshmukh Shailaja R , Purohit Sudha G , Sengupta Shantanu , Khanna Sangeeta , Mohammad Farhan , Garg Gaurav , Brahmachari Samir K ,   Indian Genome Variation Consortium, Mukerji Mitali
Published: September 2008

Background

Ayurveda is an ancient system of personalized medicine documented and practiced in India since 1500 B.C. According to this system an individual's basic constitution to a large extent determines predisposition and prognosis to diseases as well as therapy and life-style regime. Ayurveda describes seven broad constitution types (Prakriti s) each with a varying degree of predisposition to different diseases. Amongst these, three most contrasting types, Vata, Pitta, Kapha, are the most vulnerable to diseases. In the realm of modern predictive medicine, efforts are being directed towards capturing disease phenotypes with greater precision for successful identification of markers for prospective disease conditions. In this study, we explore whether the different constitution types as described in Ayurveda has molecular correlates.

Methods

Normal individuals of the three most contrasting constitutional types were identified following phenotyping criteria described in Ayurveda in Indian population of Indo-European origin. The peripheral blood samples of these individuals were analysed for genome wide expression levels, biochemical and hematological parameters. Gene Ontology (GO) and pathway based analysis was carried out on differentially expressed genes to explore if there were significant enrichments of functional categories among Prakriti types.

Results

Individuals from the three most contrasting constitutional types exhibit striking differences with respect to biochemical and hematological parameters and at genome wide expression levels. Biochemical profiles like liver function tests, lipid profiles, and hematological parameters like haemoglobin exhibited differences between Prakriti types. Functional categories of genes showing differential expression among Prakriti types were significantly enriched in core biological processes like transport, regulation of cyclin dependent protein kinase activity, immune response and regulation of blood coagulation. A significant enrichment of housekeeping, disease related and hub genes were observed in these extreme constitution types.

Conclusion

Ayurveda based method of phenotypic classification of extreme constitutional types allows us to uncover genes that may contribute to system level differences in normal individuals which could lead to differential disease predisposition. This is a first attempt towards unraveling the clinical phenotyping principle of a traditional system of medicine in terms of modern biology. An integration of Ayurveda with genomics holds potential and promise for future predictive medicine.
The role of the humoral immune response in the molecular evolution of the envelope C2, V3 and C3 regions in chronically HIV-2 infected patients
Authors: Borrego Pedro , Marcelino José Maria , Rocha Cheila , Doroana Manuela , Antunes Francisco , Maltez Fernando , Gomes Perpétua , Novo Carlos , Barroso Helena , Taveira Nuno
Published: September 2008

Background

This study was designed to investigate, for the first time, the short-term molecular evolution of the HIV-2 C2, V3 and C3 envelope regions and its association with the immune response. Clonal sequences of theenvC2V3C3 region were obtained from a cohort of eighteen HIV-2 chronically infected patients followed prospectively during 2–4 years. Genetic diversity, divergence, positive selection and glycosylation in the C2V3C3 region were analysed as a function of the number of CD4+ T cells and the anti-C2V3C3 IgG and IgA antibody reactivity

Results

The mean intra-host nucleotide diversity was 2.1% (SD, 1.1%), increasing along the course of infection in most patients. Diversity at the amino acid level was significantly lower for the V3 region and higher for the C2 region. The average divergence rate was 0.014 substitutions/site/year, which is similar to that reported in chronic HIV-1 infection. The number and position of positively selected sites was highly variable, except for codons 267 and 270 in C2 that were under strong and persistent positive selection in most patients. N-glycosylation sites located in C2 and V3 were conserved in all patients along the course of infection. Intra-host variation of C2V3C3-specific IgG response over time was inversely associated with the variation in nucleotide and amino acid diversity of the C2V3C3 region. Variation of the C2V3C3-specific IgA response was inversely associated with variation in the number of N-glycosylation sites.

Conclusion

The evolutionary dynamics of HIV-2 envelope during chronic aviremic infection is similar to HIV-1 implying that the virus should be actively replicating in cellular compartments. Convergent evolution of N-glycosylation in C2 and V3, and the limited diversification of V3, indicates that there are important functional constraints to the potential diversity of the HIV-2 envelope. C2V3C3-specific IgG antibodies are effective at reducing viral population size limiting the number of virus escape mutants. The C3 region seems to be a target for IgA antibodies and increasing N-linked glycosylation may prevent HIV-2 envelope recognition by these antibodies. Our results provide new insights into the biology of HIV-2 and its relation with the human host and may have important implications for vaccine design.
Surgery vs. radiotherapy in localized prostate cancer. Which is best?
Authors: Welz Stefan , Nyazi Maximilian , Belka Claus , Ganswindt Ute
Published: September 2008

Surgery and radiotherapy are currently accepted alternatives for the treatment of localized prostate cancer. In the absence of relevant randomized trials no decision regarding the superiority of any of the given approaches can be made. Up to now several cohort-based approaches indicate similar outcomes for both treatments. Based on a new population based approach, Merglen and co-workers recently concluded that surgery would offer the best chance of long-term control in terms of 10-year survival for T1–T3 prostate cancer patients. Unfortunately the strength of this trial is limited by several shortcomings. Most importantly, issues of radiation dosage have not been taken into account. In addition, several relevant parameters including Gleason score and PSA are not well balanced between the arms and the assignment to arbitrary risk groups does not reflect the real biological behaviour. Thus, the data provided do not support the strong conclusion issued by the authors. Based on the data available, surgery and radiotherapy still have to be considered as equally effective.
The GLAaS algorithm for portal dosimetry and quality assurance of RapidArc, an intensity modulated rotational therapy
Authors: Nicolini Giorgia , Vanetti Eugenio , Clivio Alessandro , Fogliata Antonella , Korreman Stine , Bocanek Jiri , Cozzi Luca
Published: September 2008

Background

To expand and test the dosimetric procedure, known as GLAaS, for amorphous silicon detectors to the RapidArc intensity modulated arc delivery with Varian infrastructures and to test the RapidArc dosimetric reliability between calculation and delivery.

Methods

The GLAaS algorithm was applied and tested on a set of RapidArc fields at both low (6 MV) and high (18 MV) beam energies with a PV-aS1000 detector. Pilot tests for short arcs were performed on a 6 MV beam associated to a PV-aS500. RapidArc is a novel planning and delivery method in the category of intensity modulated arc therapies aiming to deliver highly modulated plans with variable MLC shapes, dose rate and gantry speed during rotation. Tests were repeated for entire (360 degrees) gantry rotations on composite dose plans and for short partial arcs (of ~6 or 12 degrees) to assess GLAaS and RapidArc mutual relationships on global and fine delivery scales. The gamma index concept of Low and the Modulation Index concept of Webb were applied to compare quantitatively TPS dose matrices and dose converted PV images.

Results

The Gamma Agreement Index computed for a Distance to Agreement of 3 mm and a Dose Difference (ΔD) of 3% was, as mean ± 1 SD, 96.7 ± 1.2% at 6 MV and 94.9 ± 1.3% at 18 MV, over the field area. These findings deteriorated slightly is ΔD was reduced to 2% (93.4 ± 3.2% and 90.1 ± 3.1%, respectively) and improved with ΔD = 4% (98.3 ± 0.8% and 97.3 ± 0.9%, respectively). For all tests a grid of 1 mm and the AAA photon dose calculation algorithm were applied. The spatial resolution of the PV-aS1000 is 0.392 mm/pxl. The Modulation Index for calculations resulted 17.0 ± 3.2 at 6 MV and 15.3 ± 2.7 at 18 MV while the corresponding data for measurements were: 18.5 ± 3.7 and 17.5 ± 3.7. Partial arcs findings were (for ΔD = 3%): GAI = 96.7 ± 0.9% for 6° rotations and 98.0 ± 1.1% for 12° rotations.

Conclusion

The GLAaS method can be considered as a valid Quality Assurance tool for the verification of RapidArc fields. The two implementations (composite rotation or short arcs) allow the verification of either the entire delivery or of short partial segments to possibly identify local discrepancies between delivery and calculations. RapidArc, according to the findings, appears to be a safe delivery method in terms of dosimetric accuracy allowing its clinical application.
Retention of foreign body in the gut can be a sign of congenital obstructive anomaly: a case report
Authors: Subudhi Pravas Chandra , Singh Shivaram Prasad , Meher Chudamani , Agrawal Omprakash
Published: September 2008

Introduction

Small smooth objects that enter the gut nearly always pass uneventfully through the gastrointestinal tract. Retention of foreign objects may occur due to congenital obstructive anomaly of the gut.

Case presentation

We report here a child who presented with features of small gut obstruction which were attributed to a foreign body impacted in the intestine. At surgery, an annular pancreas was detected and the foreign body was found to be lodged in the distended proximal duodenum.

Conclusion

The reported case highlights the fact that an impacted radio-opaque foreign body in a child should warn the pediatrician to the possibility of an obstructive congenital anomaly.
In GFP with high risk HPV-18E6 fusion protein expressed 293T and MCF-7 cells, the endogenous wild-type p53 could be transiently phosphorylated at multiple sites
Authors: Sun Lina , Zhang Ge , Li Zongfang , Song Tusheng , Huang Chen , Si Lusheng
Published: September 2008

Background

Infected cells recognize viral replication as a DNA damage stress and elicit the host surveillance mechanism to anti-virus infection. Modulation of the activity of tumor suppressor p53 is a key event in the replication of many viruses. They could manipulate p53 function through phosphorylation modification for their own purpose. But there is rarely research about p53 phosphorylation status in the context of HPV-E6. Therefore, we investigated whether p53 could be phosphorylated by HPV-E6.

Methods

We used a mammalian green fluorescence protein (GFP) expression system to express HPV-18E6 with GFP fusion proteins (GFP-18E6) in wild-type (wt) p53 cell lines, such as 293T and MCF-7 cells to trace the traffic and subcellular location of E6 protein. By immunofluorescence technique and immunoblotting, we determined the positive phosphorylated sites of p53 and observed the distribution of phosphorylated p53 in the context of GFP-18E6.

Results

GFP-18E6 was predominantly located in nuclei of wt p53 cell lines, and it could induce transient phosphorylation of p53 at multiple sites, such as Ser15, Ser20, and Ser392. All the three sites of phosphorylated p53s were localized in nuclei together with GFP-18E6.

Conclusion

In GFP with high risk HPV-18E6 fusion protein expressed 293T and MCF-7 cells, the endogenous wt p53 could be transiently phosphorylated at multiple sites.
Induction of HLA-B27 heavy chain homodimer formation after activation in dendritic cells
Authors: Santos Susana G , Lynch Sarah , Campbell Elaine C , Antoniou Antony N , Powis Simon J
Published: September 2008

Introduction

Ankylosing spondylitis (AS) is a severe, chronic inflammatory arthritis, with a strong association to the human major histocompatibilty complex (MHC) class I allele human leucocyte antigen (HLA) B27. Disulfide-linked HLA-B27 heavy-chain homodimers have been implicated as novel structures involved in the aetiology of AS. We have studied the formation of HLA-B27 heavy-chain homodimers in human dendritic cells, which are key antigen-presenting cells and regulators of mammalian immune responses.

Method

Both an in vitro dendritic-like cell line and monocyte-derived dendritic cells from peripheral blood were studied. The KG-1 dendritic-like cell line was transfected with HLA-B27 cDNA constructs, and the cellular distribution, intracellular assembly and ability of HLA-B27 to form heavy-chain homodimers was compared with human monocyte-derived dendritic cells after stimulation with bacterial lipopolysaccharide (LPS).

Results

Immature KG-1 cells expressing HLA-B27 display an intracellular source of MHC class I heavy-chain homodimers partially overlapping with the Golgi bodies, but not the endoplasmic reticulum, which is lost at cell maturation with phorbyl-12-myristate-13-acetate (PMA) and ionomycin. Significantly, the formation of HLA-B27 homodimers in transfected KG-1 cells is induced by maturation, with a transient induction also seen in LPS-stimulated human monocyte-derived dendritic cells expressing HLA-B27. The weak association of wildtype HLA-B*2705 with the transporter associated with antigen processing could also be enhanced by mutation of residues at position 114 and 116 in the peptide-binding groove to those present in the HLA-B*2706 allele.

Conclusion

We have demonstrated that HLA-B27 heavy-chain homodimer formation can be induced by dendritic cell activation, implying that these novel structures may not be displayed to the immune system at all times. Our data suggests that the behaviour of HLA-B27 on dendritic cells may be important in the study of inflammatory arthritis.
4-Hydroxynonenal induces apoptosis in human osteoarthritic chondrocytes: the protective role of glutathione-S-transferase
Authors: Vaillancourt France , Fahmi Hassan , Shi Qin , Lavigne Patrick , Ranger Pierre , Fernandes Julio C , Benderdour Mohamed
Published: September 2008

Introduction

4-Hydroxynonenal (HNE) is one of the most abundant and reactive aldehydes of lipid peroxidation products and exerts various effects on intracellular and extracellular signalling cascades. We have previously shown that HNE at low concentrations could be considered as an important mediator of catabolic and inflammatory processes in osteoarthritis (OA). In the present study, we focused on characterizing the signalling cascade induced by high HNE concentration involved in cell death in human OA chondrocytes.

Methods

Markers of apoptosis were quantified with commercial kits. Protein levels were evaluated by Western blotting. Glutathione (GSH) and ATP levels were measured with commercial kits. Glucose uptake was assessed by 2-deoxy-D-[3H]-glucose. The role of GSH-S-transferase A4-4 (GSTA4-4) in controlling HNE-induced chondrocyte apoptosis was investigated by chondrocyte transfection with small interfering RNA (siRNA) or with the expression vector of GSTA4-4.

Results

Our data showed that HNE at concentrations of up to 10 μM did not alter cell viability but was cytotoxic at concentrations of greater than or equal to 20 μM. HNE-induced chondrocyte death exhibited several classical hallmarks of apoptosis, including caspase activation, cytochrome c and apoptosis-induced factor release from mitochondria, poly (ADP-ribose) polymerase cleavage, Bcl-2 downregulation, Bax upregulation, and DNA fragmentation. Our study of signalling pathways revealed that HNE suppressed pro-survival Akt kinase activity but, in contrast, induced Fas/CD95 and p53 expression in chondrocytes. All of these effects were inhibited by an antioxidant, N-acetyl-cysteine. Analysis of cellular energy and redox status showed that HNE induced ATP, NADPH, and GSH depletion and inhibited glucose uptake and citric acid cycle activity. GSTA4-4 ablation by the siRNA method augmented HNE cytotoxicity, but, conversely, its overexpression efficiently protected chondrocytes from HNE-induced cell death.

Conclusion

Our study provides novel insights into the potential mechanisms of cell death in OA cartilage and suggests the potential role of HNE in OA pathophysiology. GSTA4-4 expression is critically important for cellular defence against oxidative stress-induced cell death in OA cartilage, possibly by HNE elimination.
Tirofiban preserves platelet loss during continuous renal replacement therapy in a randomised prospective open-blinded pilot study
Authors: Link Andreas , Girndt Matthias , Selejan Simina , Rbah Ranja , Böhm Michael
Published: September 2008

Introduction

Approximately one third of all patients with cardiogenic shock suffer from acute kidney injury. Percutaneous coronary intervention, intra-aortic balloon pump, and continuous renal replacement therapy (CRRT) require effective antiplatelet therapy and anticoagulation, resulting in a high risk for platelet loss and bleeding events. The reversible platelet glycoprotein IIb/IIIa receptor inhibitor tirofiban was investigated to preserve platelet number and activation in a prospective open-blinded endpoint evaluation study.

Methods

Forty patients with cardiogenic shock and acute kidney injury requiring CRRT were randomly assigned to two groups receiving unfractioned heparin (UFH) (n = 20) or a combined anticoagulation with UFH and tirofiban (n = 20). The primary endpoint was platelet loss during CRRT. Secondary endpoints were urea reduction, haemofilter life span, bleeding events, and necessity for platelet transfusions.

Results

In UFH-treated patients, the percentage of platelet-monocyte aggregates significantly increased (P < 0.001) and consecutively platelet cell count significantly decreased (P < 0.001). In contrast, combined treatment with UFH and tirofiban significantly decreased platelet-monocyte aggregates and platelet numbers (P < 0.001).

Conclusions

This pilot study provides evidence that the use of tirofiban in addition to UFH prevents platelet loss and preserves platelet function in patients with cardiogenic shock and acute kidney injury requiring CRRT. The pathophysiological inhibition of platelet aggregation and platelet-monocyte interaction appears to be causally involved.
Embryonic implantation: cytokines, adhesion molecules, and immune cells in establishing an implantation environment
Authors: van Mourik Maaike S M , Macklon Nick S , Heijnen Cobi J
Published: September 2008

Successful implantation is an absolute requirement for the reproduction of species, including humans. The process by which a foreign blastocyst is accepted by the maternal endometrium is complex and requires interplay of many systems. Implantation occurs during the putative implantation window, in which the maternal endometrium is ready to accept the blastocyst, which on the other hand, also plays a specific role. It produces cytokines and chemokines and expresses adhesion molecules and certain classes of MHC molecules. We review the most important players in implantation. Concerning the cytokines, the establishment of controlled aggression is key; an excess of pro- or anti-inflammation is detrimental to pregnancy outcome. Chemokines control the orientation of the embryo. The adhesion molecules are necessary to establish the required physical interaction between mother and blastocyst. Finally, immune cells and in particular, uterine NK and regulatory T cells are pivotal in inducing tolerance to the blastocyst. The aim of this review is to discuss mechanisms at play and their relative importance to the establishment of pregnancy.
On the use of multicomponent streamer recordings for reconstruction of pressure wavefields in the crossline direction
Authors: Robertsson Johan O. , Moore Ian , Vassallo Massimiliano , Özdemir Kemal , van Manen Dirk-Jan , Özbek Ali
Published: September 2008

Three-component measurements of particle motion would bring significant benefits to towed-marine seismic data if processed in conjunction with the pressure data. We show that particle velocity measurements can increase the effective Nyquist wavenumber by a factor of two or three, depending on how they are used. A true multicomponent streamer would enable accurate data reconstruction in the crossline direction with cable separations for which pressure-only data would be irrecoverably aliased. We also show that conventional workflows aimed at reducing these aliasing effects, such as moveout correction applied before interpolation, are compatible with multicomponent measurements. Some benefits of velocity measurements for deghosting data are well known. We outline how the new measurements might be used to address some long-standing deghosting challenges of particular interest. Specifically, we propose methods for recovering de-ghosted data between streamers and for 3D deghosting of seismic data at the streamer locations.
Global optimization with model-space preconditioning: Application to AVO inversion
Authors: Misra Somanath , Sacchi Mauricio D.
Published: September 2008

Linearized-inversion methods often have the disadvantage of dependence on the initial model. When the initial model is far from the global minimum, optimization is likely to converge to a local minimum. Optimization problems involving nonlinear relationships between data and model are likely to have more than one local minimum. Such problems are solved effectively by using global-optimization methods, which are exhaustive search techniques and hence are computationally expensive. As model dimensionality increases, the search space becomes large, making the algorithm very slow in convergence. We propose a new approach to the global-optimization scheme that incorporates a priori knowledge in the algorithm by preconditioning the model space using edge-preserving smoothing operators. Such nonlinear operators acting on the model space favorably precondition or bias the model space for blocky solutions. This approach not only speeds convergence but also retrieves blocky solutions. We apply the algorithm to estimate the layer parameters from the amplitude-variation-with-offset data. The results indicate that global optimization with model-space-preconditioning operators provides faster convergence and yields a more accurate blocky-model solution that is consistent with a priori information.
Performance ofBRCA1/2Mutation Prediction Models in Asian Americans
Authors: Kurian Allison W. , Gong Gail D. , Chun Nicolette M. , Mills Meredith A. , Staton Ashley D. , Kingham Kerry E. , Crawford Beth B. , Lee Robin , Chan Salina , Donlon Susan S. , Ridge Yolanda , Panabaker Karen , West Dee W. , Whittemore Alice S. , Ford James M.
Published: September 2008

Purpose

There are established differences in breast cancer epidemiology between Asian and white individuals, but little is known about hereditary breast cancer in Asian populations. Although increasing numbers of Asian individuals are clinically tested for BRCA1/2 mutations, it is not known whether computer models that predict mutations work accurately in Asian individuals. We compared the performance in Asian and white individuals of two widely used BRCA1/2 mutation prediction models, BRCAPRO and Myriad II.

Patients and Methods

We evaluated BRCAPRO and Myriad II in 200 Asian individuals and a matched control group of 200 white individuals who were tested for BRCA1/2 mutations at four cancer genetics clinics, by comparing numbers of observed versus predicted mutation carriers and by evaluating area under the receiver operating characteristic curve (AUC) for each model.

Results

BRCAPRO and Myriad II accurately predicted the number of white BRCA1/2 mutation carriers (25 observed v 24 predicted by BRCAPRO; 25 predicted by Myriad II, P ≥ .69), but underpredicted Asian carriers by two-fold (49 observed v 25 predicted by BRCAPRO; 26 predicted by Myriad II; P ≤ 3 × 10−7). For BRCAPRO, this racial difference reflects substantial underprediction of Asian BRCA2 mutation carriers (26 observed v 4 predicted; P = 1 × 10−30); for Myriad II, separate mutation predictions were not available. For both models, AUCs were nonsignificantly lower in Asian than white individuals, suggesting less accurate discrimination between Asian carriers and noncarriers.

Conclusion

Both BRCAPRO and Myriad II underestimated the proportion of BRCA1/2 mutation carriers, and discriminated carriers from noncarriers less well, in Asian compared with white individuals.
Cognitive and Adaptive Outcome in Extracerebellar Low-Grade Brain Tumors in Children: A Report From the Children's Oncology Group
Authors: Ris M. Douglas , Beebe Dean W. , Armstrong F. Daniel , Fontanesi John , Holmes Emi , Sanford Robert A. , Wisoff Jeffrey H.
Published: September 2008

Purpose

To determine whether pediatric patients treated with surgery only for low-grade tumors in the cerebral hemispheres, supratentorial midline, and exophytic brainstem evidence neurocognitive, academic, adaptive, or emotional/behavioral sequelae.

Patients and Methods

Ninety-three patients from a natural history study of low-grade astrocytomas were tested an average of 111 days after surgery. Rates of below average (≤ 25th percentile) scores in this sample were compared with test norms, and performances were compared across anatomic sites. Finally, the relationships of pre-, peri-, and postsurgical complications to outcome were investigated.

Results

For the entire sample, there was a significantly elevated rate of below average scores across intelligence quotient, achievement, and adaptive behavior, but not behavioral/emotional adjustment measures. Patients with hemispheric, midline, and brainstem tumors did not differ significantly. Patients with left hemisphere tumors generally performed worse than those with right hemisphere tumors. Finally, neurobehavioral outcome was unrelated to pre-, peri-, or postsurgery complications.

Conclusion

After surgery for low-grade brain tumors, a significant number of patients was found to function below average, by as much as 55% compared with 25% in the normative population. Moreover, these results suggest greater risk for patients with lesions situated in the left cerebral hemisphere. Routine neuropsychological follow-up of children after treatment for low-grade tumors is recommended.
Of Time and Eternity
Authors: Renwick William
Published: September 2008

This essay discusses tonal ambiguity in the chorale melody “Das alte Jahr” and suggests a poetic interpretation of Bach's chorale. Expressive elements such as the passus duriusculus, the sospiro, and pervasive chromaticism are woven into a radical tonal plan that reflects a multifaceted perspective on time suggested by the change of year. In particular, the chromatic fourth becomes a tonality-defining element that contrasts the essentially diatonic melody. I suggest that the tonal and motivic balances in the piece reflect the duality of regret for the past and hope for the future, as well as a cyclic harmonic plan that reflects the yearly cycle and the notion of spiritual transformation.
Modelling and optimization of the resistance spot welding process via a Taguchi—neural approach in the automobile industry
Authors: Lin H-L , Chou T , Chou C-P
Published: September 2008

Many parameters affect the quality of the resistance spot welding (RSW) process. It is not easy to obtain optimal parameters of the RSW process in the automobile industry. Conventionally, the Taguchi method has been widely used in engineering; however, with this method the desired results can only be obtained with the use of very discrete control factors, thus leading to uncertainty about the real optimum. In the process to weld the low-carbon sheet steels of the auto body, the Taguchi method was used for the initial optimization of the RSW process parameters. A neural network with the Levenberg—Marquardt back-propagation algorithm was then adopted to develop the relationships between the welding process parameters and tensile shear strength of each specimen. The optimal parameters of the RSW process were determined by simulating the process parameters using a well-trained neural network model. Experimental results illustrate the Taguchi—neural approach.
Elasticity of a farm trailer's chassis at different twisting angles
Authors: Akdemir B , Ulger P , Eker B , Saglam C , Celen I , Aktas T , Avci G
Published: September 2008

It is important to know the behaviours of materials used to design and manufacture farm trailers in the same way as is necessary for all mechanical systems. Fatigue tests for trailers give an idea about the behaviours of its components. Simulators are very useful test systems for applying fatigue tests under laboratory conditions. The aim of this research was to determine the effects of different twisting angles of a trailer chassis on a farm trailer by using a simulator apparatus. Tests were carried out in either static or dynamic conditions. The minimum and maximum twisting angles were selected as −10° and +10° for all tests respectively. The farm trailer was twisted for each 2° and the system was stopped to measure the forces for static conditions. Measured forces were used to calculate the twisting moments. The experimental apparatus ran continuously between −10° and +10° and the forces were measured for each 2° under dynamic conditions. The tests were performed at 26 cycles/min for twisting angles of ±10°. The energy absorbed through hysteresis by the trailer chassis was calculated as 27980Nm. The total energy and the coefficient of absorption ability of the chassis were calculated as 107849Nm and 25.9 per cent respectively. The materials of the trailer chassis must be more elastic than this value according to the literature to absorb vibrations created by the road or field. When the twisting moment of the trailer is smaller, it is possible that the trailer may fall over when going round a bend in the road. Stability requires high twisting moments. The absorption of vibration, however, requires smaller twisting moments.
Modelling gas flow pressure gradients in gelcast ceramic foam diesel particulate filters
Authors: Adigio E M , Binner J G P , Garner C P , Hague R J , Williams A M
Published: September 2008

New mathematical models are proposed that predict fluid flow pressure gradients in gelcast ceramic foam diesel exhaust particulate filters by considering the foam structure conceptually as serially connected orifices. The resulting multiple orifice mathematical (MOM) model is based on the sum of a viscous term derived from an extended Ergun model and the kinetic energy loss derived from the Bernoulli and conservation of mass equations. The MOM model was calibrated using experimental data obtained from measuring the air flowrate and pressure drop across a physical large-scale three-dimensional model of a cellular foam structure produced using rapid manufacturing techniques. The calibrated model was then validated using fluid flow data obtained from gelcast ceramic foam filters of various cell sizes and was found to require no empirical recalibration for each gelcast ceramic foam sample. The MOM model for clean filters was extended to predict pressure gradients of filters loaded with particulate matter (PM). The prediction of pressure gradients through gelcast ceramic filters using the MOM model for clean and PM-loaded cases was shown to be in reasonable agreement with experimental data. The models were finally applied to design a filter for a turbocharged, charge-cooled, 2.0l, four-stroke, common rail, direct injection passenger car diesel engine.
Effects of design and adhesive modulus on the torsional stiffness of automotive structures
Authors: Fellows N A , Harris A , Durodola J F , Beevers A
Published: September 2008

The torsional stiffness of automotive structures is one of the major factors that affect vehicle handling, safety, and passenger comfort. Several factors such as material property, geometry, and joining technique contribute to the stiffness of a structure. This paper investigates the effect of adhesive modulus on the torsional stiffness of idealized box beams and plenum chambers for a luxury car. The effect of the adhesive modulus was investigated by considering four different adhesives ranging in modulus from 6MPa to 3GPa. To assess the influence of the apertures, some tests were carried out on box beams containing a single aperture on one side. Spot-welded plenum chambers and beams were also tested to provide a comparison of adhesive performance against conventional methods of joining. The effect of the adhesive modulus and the apertures in the plenum chambers on the results are discussed in the light of the results obtained, as well as the suitability of using adhesive bonding to reduce the vehicle weight.
Effects of carbon dioxide in-cylinder injection on premixed charge compression ignition combustion
Authors: Qu S , Deng K-Y , Cui Y , Shi L
Published: September 2008

In this study, two fuel injections were used to realize premixed charge compression ignition combustion. The first was during the negative valve overlap period; the second was just before the compression top dead centre. First, the effects of the second fuel injection timing are discussed, and then carbon dioxide (CO2) in-cylinder injection parameters, including injection timing, injection quantity, and injection pressure, are discussed. In addition, CO2 in-cylinder and intake pipe injection are also compared in the study of injection quantity. The results revealed that, for CO2 in-cylinder injection, either advancing CO2 injection timing or increasing cyclic injection quantity can greatly reduce the emission of nitrogen oxides (NO x) with little impairment of the thermal efficiency. With increase in the CO2 injection quantity, intake pipe injection has a similar effect to external exhaust gas recirculation, such as NO x emission reduction accompanied by smoke increase; while CO2 in-cylinder injection has a weaker effect in reducing NO x emission than intake-pipe injection does, it has little effect on smoke. Generally, with the same CO2 injection quantity, higher injection pressure results in higher momentum flux and total momentum. Since larger momentum flux and momentum have a stronger disturbance on the air—fuel mixture, resulting in a more homogeneous mixture, a larger injection pressure leads to lower NO x emission.
Confidence limits for motorcycle speed from slide distance
Authors: Wood D P , Alliot R , Glynn C , Simms C K , Walsh D G
Published: September 2008

In many motorcycle accidents, the motorcycle falls to the ground and slides to rest following impact or loss of control. The determination of the motorcycle speed just prior to ‘fall-over’ is important for biomechanics research and for litigation. This paper presents a new model of motorcycle fall-over and slide, which accounts for the loss of horizontal momentum resulting from the initial motorcycle-to-ground impact and the subsequent slide to rest. The model includes cases involving motorcycle fall-over owing to loss of control as well as impact. The models represent both the mean and variation present in the available experimental data for dry roads very well and are used to develop confidence limits for accident reconstruction purposes, in cases where only the motorcycle slide distance along the ground is known. Previously proposed confidence limit criteria are applied to predicting motorcycle speed ranges from slide distance, and it is shown that the level of prediction uncertainty can be substantially reduced in cases where additional information specific to the vehicle and road configurations is available.
The effect of diesel engine operating conditions on exhaust particle size distributions
Authors: Armas O , Ballesteros R , Gómez A
Published: September 2008

Owing to the negative effects that aerosols have on human health, the interest in knowing the size and the amount of particulate matter emitted by diesel engines is increasing. The measurement of this kind of aerosol is mainly influenced by three parameters: the ambient conditions, the sampling method used to characterize the emissions together with the system used to determine the particle size distributions, and, finally, the physical and chemical characteristics of the aerosol, which are a direct consequence of those processes occurring in the engine (composition, size, and concentration of particles in the aerosol, amount of volatile organic compounds, sulphur compounds, and different residues coming from the additives used in fuels and lubricants, etc.). An experimental study has been developed which combines the use of a partial dilution minitunnel and a scanning mobility particle sizer. The aim is to study the influence that the engine operating conditions which the driver can control by using the throttle while driving a vehicle, i.e. the torque and engine speed, have on the particle size distribution and its statistical parameters, namely the mean diameter and total concentration. This study was carried out on a light-duty direct-injection diesel engine which is used currently on European roads. Four steady operation modes were tested, from the most emissions-significant zones of the engine map. Likewise, a complementary study has been developed for a better understanding of the combined effect of both fuel-to-air and exhaust gas recirculation (EGR) ratios. In this latter study the EGR was completely eliminated from the engine modes previously studied.
An interval type-2 fuzzy logic controller for quarter-vehicle active suspensions
Authors: Cao J , Liu H , Li P , Brown D
Published: September 2008

A novel adaptive fuzzy logic controller (AFC) based on an interval type-2 fuzzy controller is proposed for vehicle non-linear active suspension systems. The adaptive strategy elicited from the least-mean-squares optimal algorithm is adopted to self-tune lower bounds and upper bounds of interval type-2 fuzzy membership functions (IMF2s). The IMF2s are utilized in the AFC design to deal with not only non-linearity and uncertainty caused by irregular road inputs and immeasurable disturbance, but also the potential uncertainty of experts knowledge and experience. A case study based on a quarter-vehicle active suspension model has demonstrated that the proposed type-2 controller significantly outperforms conventional fuzzy controllers of an active suspension and a passive suspension.
Anthropometrical limitations in the construction of passenger vehicles: Case study
Authors: Klarin M M , Spasojević-Brkić V K , Stanojević P D , Sajfert Z D
Published: September 2008

The result of anthrometrical limitations is, among other things, the usual construction of passenger automobiles for a range from a 5th-percentile woman to a 95th-percentile man driver, determining the position and adjustability (movement) of the seat, the position and angle of the windscreen, and the torso of the driver.

Anthropometrical changes, especially the form of the stochastic normal function for the division of certain measures in Serbia and possibly at the global level, influence the increase in all anthropometrical values but also influence the difference between the measurements for the 5th-percentile woman and the 95th-percentile man driver, for which range the passenger automobile is usually adjusted. On the other hand, this leads to difficulties and the impossibility of normal use of the steering wheel with the hands of a small 5th-percentile aged woman because they are too near, and also the 95th-percentile aged man driver, because they are too far. Therefore, the usual design of the steering wheel for a total 50th-percentile hermaphrodite (man—woman) is no longer sustainable, but the tip of the steering-wheel shaft should also be adjusted to suit a certain range, until a more acceptable technical solution is found.
Roll state estimator for rollover mitigation control
Authors: Park J-I , Yoon J-Y , Kim D-S , Yi K-S
Published: September 2008

This paper describes a new methodology for designing model-based estimators for detecting impending vehicle rollover. Vehicle roll motions are induced by manoeuvring and road disturbances. An estimator is designed on the basis of a three-degree-of-freedom vehicle manoeuvring model and a four-degree-of-freedom half-car suspension model to obtain good estimates of the vehicle roll angle and roll rate in driving situations in which both manoeuvring and road disturbances affect the vehicle roll motions. The estimator uses existing sensors, such as the steering wheel angle sensor, lateral acceleration sensor, and yaw rate sensor, on a vehicle equipped with an electronic stability control system. Since road disturbance is unknown or very expensive to measure, disturbance-decoupled-observer design technique is used in the design of the estimator. The parameter adaptation algorithm can be used for vehicle mass to improve the accuracy of estimator. The performance of the estimator is evaluated through computer simulations using a validated vehicle simulator. It is shown that, with only the sensor measurements already available, good estimates of the roll angle and roll rate can be obtained using the proposed estimator in driving situations in which both manoeuvring and road disturbances affect the vehicle roll motions. A rollover index that indicates rollover danger has been computed using the measured lateral acceleration and yaw rate, and the estimated roll angle and roll rate. The rollover index computed using the estimated states is shown to be a good measure for the danger of vehicle rollover.