bluuebunny/crossref_metadata_2025 huggingface dataset:
Early life-stage toxicity in zebrafish (Danio rerio) following embryonal exposure to selected polychlorinated biphenyls
Authors: Şişman T , Geyikoğlu F , Atamanalp M
Published: June 2008

Polychlorinated biphenyls are a widespread aquatic contaminant. In this article, specific polychlorinated biphenyl congeners were examined for embryo and early life-stage toxicity in zebrafish ( Danio rerio). A set of three polychlorinated biphenyl congeners (non-ortho polychlorinated biphenyl 126, mono-ortho polychlorinated biphenyl 28 and di-ortho polychlorinated biphenyl 153) were tested. The typical lesions observed were yolk sac edema, vertebra defect, craniofacial malformations (double head, triple retina), anaxial body and inhibition of swim bladder inflation. Moreover, embryo and larval mortality increased and hatching success decreased. The severity of abnormalities and mortalities were concentration- and congener-dependent. Of the compounds tested, polychlorinated biphenyl congener 126 was found to be highly toxic to the fish embryos following exposure. The Lethal Concentration 50 values for polychlorinated biphenyl 28, polychlorinated biphenyl 126, polychlorinated biphenyl 153 calculated by probit analysis were 3.270, 1.298 and 5.375 ppm, respectively. The inhibition of swim bladder inflation was the most sensitive endpoint measured, and it is suggested that the inhibition of swim bladder inflation may be mediated by mechanism with an aryl hydrocarbon receptor activation.
Urban stressors and plasmatic 17-β-estradiol (E2) in male exposed workers
Authors: Tomei G , Rosati MV , Ciarrocca M , Capozzella A , Pimpinella B , Palitti T , Casale T , Di Famiani M , Filippelli C , Cangemi C , Giubilati R , Monti C , Tomei F
Published: June 2008

The aim of the study is to evaluate if the occupational exposure to urban stressors could cause alterations in 17-β-estradiol (E2) plasma levels and related disorders in male traffic police compared with a control group. After excluding from the study, the subjects with the principal confounding factors, traffic police and controls were matched by age, working life, Body Mass Index (BMI), smoking and drinking habit. A total of 171 male traffic police and 171 controls were included in the study. In traffic police, mean E2 values were significantly lower versus controls ( P < 0.001). The distribution of E2 values in traffic police and controls was significant ( P < 0.001). No significant differences were found in percentage of traffic police versus controls concerning the following questionnaire items: fertility and mental health diseases. Our results suggest that the occupational exposure to chemical urban stressor, interacting with and adding to the psychosocial ones, could alter plasma E2 concentrations in male traffic police compared with a control group. According to our previous researches on other neuro-immune-endocrine parameters, E2 could be used as an early biological marker, valuable for the group, to be used in occupational set even before the onset of the pathologies.
The Prevalence and Clustering of Four Major Lifestyle Risk Factors in Hong Kong Chinese Older Adults
Authors: Chou Kee-Lee
Published: June 2008

Objective: This study investigated the prevalence and clustering of four common lifestyle risk factors—cigarette smoking, heavy alcohol drinking, physical inactivity, and low consumption of vegetables and fruits—among older Chinese women and men in Hong Kong. Method: The author examined 4,812 community-dwelling older persons aged 60 and older in a cross-sectional representative study, collecting data on lifestyle risk factors and sociodemographics by in-person interviews during household visits. Results: About 5% of older persons had at least three lifestyle risk factors, and more than 90% of them were men. Clustering was found at both ends of the lifestyle spectrum, especially in older men. Prevalence of multiple risk factors was higher among men, older age groups, and those with higher levels of education but lower for those who were employed. Discussion: Findings suggest that common lifestyle risk factors cluster among older men, and the clustering of risk factors provides support for multiple-behavior interventions.
The methodology of self-controlled case series studies
Authors: Whitaker Heather J , Hocine Mounia N , Farrington C Paddy
Published: June 2008

The self-controlled case series method is increasingly being used in pharmacoepidemiology, particularly in vaccine safety studies. This method is typically used to evaluate the association between a transient exposure and an acute event, using only cases. We present both parametric and semiparametric models using a motivating example on MMR vaccine and bleeding disorders. We briefly describe approaches for interferent events and a sequential version of the method for prospective surveillance of drug safety. The efficiency of the self-controlled case series method is compared to the that of cohort and case control studies. Some further extensions, to long or indefinite exposures and to bivariate counts, are described.
Policy Development for Advocates
Authors: Johnston Sara P. , Helms Lelia B.
Published: June 2008

Calls for cross-disciplinary dialogue and greater coherence in disability policies have produced limited understanding of disability policy making. Most scholars focus on what should be done but give scant consideration to how the dynamics of the policy making process constrain substantive options. The authors argue that failing to consider the environment of the policy making processes on program design and advocacy hinders understanding about policy and development of practical initiatives. This article describes the dynamics of policy making through a case study of the Job Accommodation Network, which provides an example of path dependence and the infilling of policy spaces and exemplifies how later arriving, modest initiatives and influential advocates can target narrower niches, seek to improve collaboration, and create better linkages between stakeholders in their efforts to expand employment opportunities for persons with disabilities. The analysis has implications for advocates and practitioners by demonstrating how policy programs evolve, shape, and adapt to new policy initiatives.
Herpesviruses and human endogenous retroviral sequences in the cerebrospinal fluid of multiple sclerosis patients
Authors: Álvarez-Lafuente R , García-Montojo M , De Las Heras V , Domínguez-Mozo MI , Bartolome M , Benito-Martin MS , Arroyo R
Published: June 2008

Objective

To analyze the possible role of human herpesvirus (HHVs) and human endogenous retroviruses (HERVs) infection in multiple sclerosis (MS) pathogenesis.

Methods

A total of 92 cerebrospinal fluid (CSF) samples were collected: 48 from MS patients at the first clinically evident demyelinating event, 23 from patients with other inflammatory neurological diseases (OINDs) and 21 from patients with other non-inflammatory neurological diseases (ONINDs). Total DNA and RNA were isolated, and the prevalences and viral loads of herpes simplex virus (HSV), varicella-zoster virus (VZV), Epstein–Barr virus (EBV), cytomegalovirus (CMV), HHV-6, HERV-H and HERV-W in the CSF of MS patients and controls were evaluated using a quantitative real-time polymerase chain reaction assay.

Results

(i) For HSV, 1/48 (2.1%, 86 copies/ml of CSF) MS patients and 1/23 (4.3%, 115.2 copies/ml of CSF) OIND patients (a myelitis case) had HSV sequences in the CSF; (ii) for EBV, only 1/48 (2.1%, 72 copies/ml of CSF) MS patients was positive for EBV; (iii) for HHV-6, only 5/48 (10.4%) MS patients had HHV-6 genomes in their CSF (128.1 copies/ml of CSF); (iv) we did not find any positive cases for VZV, CMV, HERV-H and HERV-W among MS patients or controls; (v) no cases of co-infections were found; (vi) the whole prevalence of HHVs was 7/48 (14.6%) for MS patients and 1/44 (2.3%) for controls ( p = 0.038).

Conclusion

The findings described here show that HHV infection is more frequent in the CSF of MS patients than in patients with other neurological diseases; however, only HHV-6 seems to be involved in the pathogenesis of MS in a subset of patients.
Modeling the cost-effectiveness of a new treatment for MS (natalizumab) compared with current standard practice in Sweden
Authors: Kobelt G , Berg J , Lindgren P , Jonsson B , Stawiarz L , Hillert J
Published: June 2008

Objective

To estimate the cost-effectiveness of a new treatment (natalizumab) for multiple sclerosis (MS) compared with current standard therapy with disease-modifying drugs (DMDs) in Sweden.

Methods

A Markov model was constructed to illustrate disease progression based on functional disability (the Expanded Disability Status Scale (EDSS)). The effectiveness of natalizumab was based on a 2-year clinical trial in 942 patients (AFFIRM). The effectiveness of current DMDs was estimated from a matched sample of 512 patients in the Stockholm MS registry. Patients withdrawing from treatment were assumed to follow the disease course of 824 patients with relapsing–remitting disease at onset in the Ontario natural history cohort. Costs and utilities are based on a recent observational study in 1339 patients. All data sets were available at the patient level. Main results are presented from the societal perspective, over a 20-year time frame, in 2005 Euros (€1 = 9.25 SEK).

Results

In the base case, treatment with natalizumab was less expensive and more effective than treatment with current DMDs. When only healthcare costs were considered, the cost per quality-adjusted life year gained with natalizumab was €38 145. Results are sensitive only to the time horizon of the analysis and assumptions about effectiveness of natalizumab beyond the trial.

Conclusions

This cost-effectiveness analysis used registry data, cohort and observational studies to extrapolate the efficacy findings of natalizumab from the AFFIRM clinical trial to measure effectiveness in clinical practice. The analysis results suggest that for the population considered, natalizumab provides an additional health benefit at a similar cost to current DMDs from a societal perspective.
Frequency of celiac disease is not increased among multiple sclerosis patients
Authors: Nicoletti A , Patti F , Lo Fermo S , Sciacca A , Laisa P , Liberto A , Lanzafame S , Contraffatto D , D’Agate C , Russo A , Zappia M
Published: June 2008

We evaluated the presence of IgA and IgG celiac disease–related antibodies in a sample of 217 patients with multiple sclerosis (MS) and in a sample of 200 controls not affected by neurological disorders. None of the 217 patients with MS presented IgG and IgA anti-gliadin, anti-endomysial antibodies, anti-tissue transglutaminase and anti-reticulin, whereas only one of the selected controls presented specific antibodies; this subject resulted to be effectively affected by celiac disease. Our data did not show an increased frequency of celiac disease among patients with MS.
The Meaning of Race and Violence in Grand Theft Auto
Authors: DeVane Ben , Squire Kurt D.
Published: June 2008

This research study investigates how youths actually play Grand Theft Auto: San Andreas and what meanings they make from it. This study finds that players use their own experiences and knowledge to interpret the game—they do not passively receive the games' images and content. The meanings they produce about controversial subjects are situated in players' local practices, identities, and discourse models as they interact with the game's semiotic domain. The results suggest that scholars need to study players in naturalistic settings if they want to see what “effects” games are having on players.
A randomized study of clofarabine versus clofarabine plus low-dose cytarabine as front-line therapy for patients aged 60 years and older with acute myeloid leukemia and high-risk myelodysplastic syndrome
Authors: Faderl Stefan , Ravandi Farhad , Huang Xuelin , Garcia-Manero Guillermo , Ferrajoli Alessandra , Estrov Zeev , Borthakur Gautam , Verstovsek Srdan , Thomas Deborah A. , Kwari Monica , Kantarjian Hagop M.
Published: June 2008

We previously reported the feasibility of clofarabine and cytarabine combinations in AML. Questions remain as to (1) the therapeutic advantage of this combination and (2) the role of lower doses of clofarabine and cytarabine in older patients. We have conducted an adaptively randomized study of lower-dose clofarabine with or without low-dose cytarabine in previously untreated patients with AML aged 60 years and older. Patients received 30 mg/m2 clofarabine intravenously daily for 5 days with or without 20 mg/m2 cytarabine subcutaneously daily for 14 days as induction. Consolidation consisted of 3 days of clofarabine with or without 7 days of cytarabine. Seventy patients were enrolled. The median age was 71 years (range, 60-83 years). Sixteen patients received clofarabine and 54 the combination. Overall, 56% achieved complete remission (CR). CR rate was significantly higher with the combination (63% vs 31%; P = .025). Induction mortality was 19% with the combination versus 31% with clofarabine alone (P = .276). The combination showed better event-free survival (7.1 months vs 1.7 months; P = .04), but not overall survival (11.4 months vs 5.8 months; P = .1). Clofarabine plus low-dose cytarabine has a higher response rate than clofarabine alone with comparable toxicity. This trial is registered at www.clinicaltrials.gov as no. NCT00088218.
Genomic structure and expression of Jmjd6 and evolutionary analysis in the context of related JmjC domain containing proteins
Authors: Hahn Phillip , Böse Jens , Edler Stefanie , Lengeling Andreas
Published: June 2008

Background

The jumonji C (JmjC) domain containing gene 6 (Jmjd6, previously known as phosphatidylserine receptor) has misleadingly been annotated to encode a transmembrane receptor for the engulfment of apoptotic cells. Given the importance of JmjC domain containing proteins in controlling a wide range of diverse biological functions, we undertook a comparative genomic analysis to gain further insights in Jmjd6 gene organisation, evolution, and protein function.

Results

We describe here a semiautomated computational pipeline to identify and annotate JmjC domain containing proteins. Using a sequence segment N-terminal of the Jmjd6 JmjC domain as query for a reciprocal BLAST search, we identified homologous sequences in 62 species across all major phyla. Retrieved Jmjd6 sequences were used to phylogenetically analyse corresponding loci and their genomic neighbourhood. This analysis let to the identification and characterisation of a bi-directional transcriptional unit compromising the Jmjd6 and 1110005A03Rik genes and to the recognition of a new, before overseen Jmjd6 exon in mammals. Using expression studies, two novel Jmjd6 splice variants were identified and validated in vivo. Analysis of the Jmjd6 neighbouring gene 1110005A03Rik revealed an incident deletion of this gene in two out of three earlier reported Jmjd6 knockout mice, which might affect previously described conflicting phenotypes. To determine potentially important residues for Jmjd6 function a structural model of the Jmjd6 protein was calculated based on sequence conservation. This approach identified a conserved double-stranded β-helix (DSBH) fold and a HxDxnH facial triad as structural motifs. Moreover, our systematic annotation in nine species identified 313 DSBH fold-containing proteins that split into 25 highly conserved subgroups.

Conclusion

We give further evidence that Jmjd6 most likely has a function as a nonheme-Fe(II)-2-oxoglutarate-dependent dioxygenase as previously suggested. Further, we provide novel insights into the evolution of Jmjd6 and other related members of the superfamily of JmjC domain containing proteins. Finally, we discuss possibilities of the involvement of Jmjd6 and 1110005A03Rik in an antagonistic biochemical pathway.
A naturally occurring omega current in a Kv3 family potassium channel from a platyhelminth
Authors: Klassen Tara L , Spencer Andrew N , Gallin Warren J
Published: June 2008

Background

Voltage-gated ion channels are membrane proteins containing a selective pore that allows permeable ions to transit the membrane in response to a change in the transmembrane voltage. The typical selectivity filter in potassium channels is formed by a tetrameric arrangement of the carbonyl groups of the conserved amino-acid sequence Gly-Tyr-Gly. This canonical pore is opened or closed by conformational changes that originate in the voltage sensor (S4), a transmembrane helix with a series of positively charged amino acids. This sensor moves through a gating pore formed by elements of the S1, S2 and S3 helices, across the plane of the membrane, without allowing ions to pass through the membrane at that site. Recently, synthetic mutagenesis studies in the Drosophila melanogaster Shaker channel and analysis of human disease-causing mutations in sodium channels have identified amino acid residues that are integral parts of the gating-pore; when these residues are mutated the proteins allow a non-specific cation current, known as the omega current, to pass through the gating-pore with relatively low selectivity.

Results

The N.at-K

v

3.2 potassium channel has an unusual weak inward rectifier phenotype. Several mutations of two amino acids in the voltage sensing (S4) transmembrane helix change the phenotype to a typical delayed rectifier. The inward rectifier channels (wild-type and mutant) are sensitive to 4-aminopyridine (4-AP) but not tetra-ethyl ammonium (TEA), whereas the delayed rectifier mutants are sensitive to TEA but not 4-AP. The inward rectifier channels also manifest low cation selectivity. The relative selectivity for different cations is sensitive to specific mutations in the S4 helix,

Conclusion

N.at-K

v

3.2, a naturally occurring potassium channel of the Kv3 sequence family, mediates ion permeation through a modified gating pore, not the canonical, highly selective pore typical of potassium channels. This channel has evolved to yield qualitatively different ion permeability when compared to all other members of this gene family.
Maximum Spectral Demands in the Near-Fault Region
Authors: Huang Yin-Nan , Whittaker Andrew S. , Luco Nicolas
Published: June 2008

The Next Generation Attenuation (NGA) relationships for shallow crustal earthquakes in the western United States predict a rotated geometric mean of horizontal spectral demand, termed GMRotI50, and not maximum spectral demand. Differences between strike-normal, strike-parallel, geometric-mean, and maximum spectral demands in the near-fault region are investigated using 147 pairs of records selected from the NGA strong motion database. The selected records are for earthquakes with moment magnitude greater than 6.5 and for closest site-to-fault distance less than 15 km. Ratios of maximum spectral demand to NGA-predicted GMRotI50 for each pair of ground motions are presented. The ratio shows a clear dependence on period and the Somerville directivity parameters. Maximum demands can substantially exceed NGA-predicted GMRotI50 demands in the near-fault region, which has significant implications for seismic design, seismic performance assessment, and the next-generation seismic design maps. Strike-normal spectral demands are a significantly unconservative surrogate for maximum spectral demands for closest distance greater than 3 to 5 km. Scale factors that transform NGA-predicted GMRotI50 to a maximum spectral demand in the near-fault region are proposed.
Comparisons of the NGA Ground-Motion Relations
Authors: Abrahamson Norman , Atkinson Gail , Boore David , Bozorgnia Yousef , Campbell Kenneth , Chiou Brian , Idriss I. M. , Silva Walter , Youngs Robert
Published: June 2008

The data sets, model parameterizations, and results from the five NGA models for shallow crustal earthquakes in active tectonic regions are compared. A key difference in the data sets is the inclusion or exclusion of aftershocks. A comparison of the median spectral values for strike-slip earthquakes shows that they are within a factor of 1.5 for magnitudes between 6.0 and 7.0 for distances less than 100 km. The differences increase to a factor of 2 for M5 and M8 earthquakes, for buried ruptures, and for distances greater than 100 km. For soil sites, the differences in the modeling of soil/sediment depth effects increase the range in the median long-period spectral values for M7 strike-slip earthquakes to a factor of 3. The five models have similar standard deviations for M6.5-M7.5 earthquakes for rock sites and for soil sites at distances greater than 50 km. Differences in the standard deviations of up to 0.2 natural log units for moderate magnitudes at all distances and for large magnitudes at short distances result from the treatment of the magnitude dependence and the effects of nonlinear site response on the standard deviation.
Biodiversity Conservation in Tropical Agroecosystems
Authors: Perfecto Ivette , Vandermeer John
Published: June 2008

It is almost certainly the case that many populations have always existed as metapopulations, leading to the conclusion that local extinctions are common and normally balanced by migrations. This conclusion has major consequences for biodiversity conservation in fragmented tropical forests and the agricultural matrices in which they are embedded. Here we make the argument that the conservation paradigm that focuses on setting aside pristine forests while ignoring the agricultural landscape is a failed strategy in light of what is now conventional wisdom in ecology. Given the fragmented nature of most tropical ecosystems, agricultural landscapes should be an essential component of any conservation strategy. We review the literature on biodiversity in tropical agricultural landscapes and present evidence that many tropical agricultural systems have high levels of biodiversity (planned and associated). These systems represent, not only habitat for biodiversity, but also a high‐quality matrix that permits the movement of forest organisms among patches of natural vegetation. We review a variety of agroecosystem types and conclude that diverse, low‐input systems using agroecological principles are probably the best option for a high‐quality matrix. Such systems are most likely to be constructed by small farmers with land titles, who, in turn, are normally the consequence of grassroots social movements. Therefore, the new conservation paradigm should incorporate a landscape approach in which small farmers, through their social organizations, work with conservationists to create a landscape matrix dominated by productive agroecological systems that facilitate interpatch migration while promoting a sustainable and dignified livelihood for rural communities.
Dysregulation of Adipose Glutathione Peroxidase 3 in Obesity Contributes to Local and Systemic Oxidative Stress
Authors: Lee Yun Sok , Kim A Young , Choi Jin Woo , Kim Min , Yasue Shintaro , Son Hee Jung , Masuzaki Hiroaki , Park Kyong Soo , Kim Jae Bum
Published: June 2008

Glutathione peroxidase 3 (GPx3) accounts for the major antioxidant activity in the plasma. Here, we demonstrate that down-regulation of GPx3 in the plasma of obese subjects is associated with adipose GPx3 dysregulation, resulting from the increase of inflammatory signals and oxidative stress. Although GPx3 was abundantly expressed in kidney, lung, and adipose tissue, we observed that GPx3 expression was reduced selectively in the adipose tissue of several obese animal models as decreasing plasma GPx3 level. Adipose GPx3 expression was greatly suppressed by prooxidative conditions such as high levels of TNFα and hypoxia. In contrast, the antioxidant N-acetyl cysteine and the antidiabetic drug rosiglitazone increased adipose GPx3 expression in obese and diabetic db/db mice. Moreover, GPx3 overexpression in adipocytes improved high glucose-induced insulin resistance and attenuated inflammatory gene expression whereas GPx3 neutralization in adipocytes promoted expression of proinflammatory genes. Taken together, these data suggest that suppression of GPx3 expression in the adipose tissue of obese subjects might constitute a vicious cycle to expand local reactive oxygen species accumulation in adipose tissue potentially into systemic oxidative stress and obesity-related metabolic complications.
Open Adoption and the Politics of Transnational Feminist Human Rights
Authors: Sotiropoulos Karen
Published: June 2008

This brief essay offers a rumination on the history and implications of open adoption, with a particular focus on the ways the practice grew out of the women's rights movement of the 1970s and on the ways racial inequities impacted child adoption before and after the rise of openness movements. It draws on a surge of recent scholarly work on child adoption to explore connections between race, child welfare, women's rights, and transnationalism. It also raises the question of child adoption as a human rights issue by considering together activist trends in domestic and international adoption. Finally, it suggests that paired with the political movement for more openness in adoption, the developing field of “adoption studies” may help pave the way for making adoption a more ethical practice.
Teaching about Transnational Feminisms
Authors: Rupp Leila J.
Published: June 2008

This essay describes a graduate reading course in women's studies I taught at the University of California at Santa Barbara in the spring of 2003 to contribute to a consideration of teaching about women's movements, human rights, and transnationalism. My goal in the course was to provide a solid historical background for contemporary questions about the feasibility of transnational feminist activism, the legacies of feminist imperialism and feminist orientalism, the diversity of women's movements, the impact of globalization on women, and the relationship between women's rights and human rights. Thinking about the material we read, the issues we discussed, and the analyses produced by a diverse group of students, I conclude by suggesting that we cannot afford to ignore the ways in which—both in the past and in the present—women (and, of course, men as well) have come together across differences of nationality to fight for human rights and social justice.
The Soul of Socialism: Christianity, Civilization, and Citizenship in the Thought of Eugene Debs
Authors: Burns Dave
Published: June 2008

Eugene Debs underwent a transformation over the course of his life that compelled him to replace a brand of unionism rooted in nationalism with a variant of socialism based on internationalism. As a trade and industrial unionist, Debs employed American political traditions linked to citizenship to attack the inequality and injustice engendered by corporations. After he became a socialist, however, Debs seriously questioned the values of citizenship and the heritage of the American Revolution, ultimately transcending the ideological framework he had utilized as a unionist. Previous historians have missed this shift in Debs's thought because they have presented his Christianity as an extension of his preoccupation with citizenship and the American Revolution. Debs emerged from a republican tradition, but his concern with the fate of humanity led him to substitute his earlier focus on American citizenship with the interests of a worldwide civilization. This process of growth caused Debs to elevate socialism in order to denigrate capitalism, exchange the particular virtues of independence and liberty for the universal values of interdependence and brotherhood, and swap the founding fathers and their revolution for Jesus and his revolutionary gospel. In the end, Debs was more concerned with perfecting the internationalist goals of civilization than the nationalist values of citizenship, and he believed that the perfection of humanity endorsed by Christianity was also the overarching goal of socialism.
Thermal analysis of a liquid-petroleum-liquid injection engine piston using the inverse heat conduction method
Authors: Lee B Y , Kim W J
Published: June 2008

An efficient method utilizing the concept of inverse heat conduction is presented for the thermal analysis of pistons based on application to a liquid-petroleum-liquid injection (LPLI) engine piston. An inverse heat conduction problem is established in the form of an optimization problem. In the optimization problem, the convection heat transfer coefficient (HTC) on the combustion-side surface of the piston is defined as the design variable, while the error between the measured and analysed temperatures is defined as the objective function. For the optimization, two consecutive steps consisting of an axisymmetric and a three-dimensional problem are presented in order to reduce computation time and to obtain stable convergence. The optimum distribution of the HTC at the top surface of the piston is successfully determined through a numerical implementation. The temperature obtained via an analysis using the optimum HTC is compared with the measured temperature, and reasonable agreement is obtained. The present method can be effectively utilized to analyse the temperature distribution of engine pistons.
An anamorphic automobile headlamp design
Authors: Liou Yuan Chang
Published: June 2008

An automobile projector headlamp design with a new anamorphic elliptical reflector and aspherical lens is proposed in this paper. An adopted aspherical model with the fourth-order cross-section equation designs the thick projection lens for good focusing results. A proposed anamorphic elliptical reflector surface with axial lengths varying with the rotating angle can control the light pattern in a simpler and more efficient way. A flat screen is applied to avoid manufacturing difficulties. The whole system in the low-beam concrete design example shows a horizontally wide and vertically narrow light pattern that sufficiently meets the ECE R112 regulations.
Command steering of trailers and command-steering-based optimal control of an articulated system for tractor-track following
Authors: Rangavajhula K , Tsao H-S J
Published: June 2008

First the effectiveness of command steering of trailers in reducing off-tracking during a 90° turn for a truck with three trailers is examined. In command steering, front trailer axles are steered proportionately to the articulation angles between the tractor and corresponding trailers. Then, based on insights gained, the approach of an optimal linear quadratic regulator (LQR) controller to minimize off-tracking indirectly, by minimizing rearward amplification, is used. The simulation results demonstrate that command steering is very effective only for low speeds, although it also reduces the turn radius during a 90° turn. Command-steering-based LQR control is, however, very effective for all speeds.
Effects of the addition of ethanol and cetane number improver on the combustion and emission characteristics of a compression ignition engine
Authors: Ren Y , Huang Z-H , Jiang D-M , Li W , Liu B , Wang X-B
Published: June 2008

Combustion and emission characteristics of a direct-injection diesel engine fuelled with diesel—ethanol blends were investigated. The results show that the ignition delay and the premixed combustion duration increase, while the diffusive combustion duration and the total combustion duration decrease with increase in the oxygen mass fraction in the blends. The addition of 0.2 per cent volume fraction of cetane number improver (isoamyl nitrite) could mean that the ignition delay and the premixed combustion duration of the fuel blends with 10vol% ethanol fraction recover to those of diesel fuel. Meanwhile, with the increase in the ethanol fraction in the fuel blends, the centre of the heat release curve moves closer to the top dead centre. The brake specific fuel consumption increases, while the diesel equivalent brake specific fuel consumption decreases with increase in the ethanol fraction. The exhaust smoke concentration increases and exhaust nitrogen oxide (NO x) concentration decreases on prolonging the fuel delivery advance angle for both diesel fuel and the blended fuels. For a specific fuel injection advance angle, the exhaust smoke concentration shows a large decrease and the exhaust NO x concentration a small decrease on ethanol addition.
Experimental investigation into particulate size and number distribution from a spark ignition engine: In-cylinder combustion and transient events
Authors: Sturgess J , Hill B , Samuel S
Published: June 2008

The work presented here had two main aims: first, it investigated the relationship between in-cylinder combustion performance and particulate size distribution and number count; second, it examined the possibility of reconstructing transient events using steady state test data relating to particulate size distribution and number count. It identified a strong correlation between the geometric mean diameter (GMD) of the engine-out particulate matter and the rate of burning during the early stage of combustion. In addition, it identified correlations between the coefficient of variance for 50 per cent mass fraction burned and the coefficient of variance for particulate GMD. The tests relating to transient events identified that steady state data can be used to reconstruct acceleration events, but not deceleration events. The methodology followed to obtain these findings is detailed in this paper.
Active geometry control suspension system for the enhancement of vehicle stability
Authors: Lee U K , Lee S H , Han C S , Hedrick K , Català A
Published: June 2008

The active control of suspension geometry has historically been a challenging perspective for chassis teams of worldwide automakers. Manufacturers and suppliers have offered different solutions, but few have succeeded in combining a marked improvement in handling performance, low-energy consumption, simplicity, and low cost.

The new and revolutionary approach of an active geometry control suspension (AGCS) reinvents the possibilities of rear-suspension active toe control. This system employs the use of the complexity of a rear multi-link suspension, and a clever design layout to minimize the energy use. Additionally, because of an efficient control logic strategy, the vehicle-handling performance and stability are substantially improved. The system is the most successful in controlling vehicle transient situations initiated mainly by aggressive lane-change manoeuvres at medium to high speeds.

This paper presents the most relevant actions of the development process of the AGCS. The use of different evaluation methods and accurate measurement equipment was crucial for optimization of the system. The methods presented combine subjective evaluations in different road conditions (icy, wet, and dry asphalt), suspension kinematics and elastokinematics characterization, and objective road measurements using dynamic wheel position measurement equipment.

Finally, a comprehensive summary of the handling-test results are explained, which outline the efficiency of the system, and its influence on the active safety level of the vehicle.
Experimental and numerical study of a spark ignition engine with air-assisted direct injection
Authors: Boretti A , Jin S-H , Brear M , Zakis G , Attard W , Watson H , Brewster S , Bryce W
Published: June 2008

An experimental and numerical study of the spray from an air-assisted fuel injector in a direct-injection spark ignition (DISI) engine is presented. The experiments are performed using ultraviolet laser diagnostics in a motoring optical engine that is a DISI variant of a production port-fuel-injected engine. Non-optical single-cylinder firing engine results of experiments and simulations are also presented. Recent related work by the present authors has shown that, under design conditions, the air-assisted injector exhibits strong coupling between the liquid and gas phases. It results in a filled-in conical spray of relatively fine atomization and low penetration, with liquid and vapour fuel concentrations close to the centrally located injector and spark plug, as required for lean stratified operation. This paper shows the strong effect of increasing the chamber temperature on spray evaporation and penetration. This observed temperature effect shows that spray evaporation should vary significantly during cold start. Exhaust gas recirculation (EGR) may also have a beneficial effect on DISI engine performance through enhanced spray evaporation, although this is difficult to verify experimentally. If true, this effect of EGR is a separate mechanism to the known beneficial effects of EGR in air-assisted DISI engines.
An investigation and evaluation of variable-valve-timing and variable-valve-actuation strategies in a diesel homogeneous charge compression ignition engine using three-dimensional computational fluid dynamics
Authors: Peng Z -J , Jia M
Published: June 2008

A three-dimensional computational fluid dynamics modelling was carried out to investigate effects of variable valve timing (VVT) and variable valve actuation (VVA) on gas exchange and fuel-air mixing processes in a diesel homogeneous charge compression ignition (HCCI) engine with early fuel injection. Four VVT or VVA strategies were conducted for this study: first, a negative valve overlap (NVO) strategy with fixed exhaust-valve-opening (EVO) and intake-valve-closing (IVC) timings but variable valve lifts, referred to as the NVO strategy; second, the NVO strategy with fixed valve profiles but variable EVO and IVC timings, referred to as the EVO strategy; third, the NVO strategy with fixed valve lifts and fixed EVO and IVC timings but variable exhaust-valve-closing (EVC) and intake-valve-opening timings, referred to as the EVC strategy; fourth, VVA with just variable valve lifts, referred to as the VMAX strategy. The results indicate that suitable NVO settings will enhance in-cylinder tumble and then increase turbulence intensity before compression end, although the increased NVO has a negative contribution to swirl ratio. It was found that reducing valve lifts alone is not an efficient way to retain the residual gas, but the function of reduced valve lifts will become significantly obvious by combining it with increasing NVO. For the effect of NVO on in-cylinder temperature, longer NVO not only will increase in-cylinder temperature because of the higher residual gas rate but also will improve the in-cylinder temperature homogeneity. On lowering the maximum valve lift or increasing the NVO, the unmixed region of the in-cylinder charge shrinks. The fuel-rich region expands because of the high intake velocity and enhanced turbulence intensity. This is beneficial to the forming of a global homogeneous charge. It has been noted from the current study that, as the droplet distribution may be influenced more by the in-cylinder air motion caused by NVO when the average droplet size is smaller, it is recommended that future studies explore the effects of VVT and VVA on diesel HCCI mixing and combustion with various advanced fuel injection strategies.
Effect of an oxidation catalyst and a three-way catalyst on odorous emissions in internal combustion engines
Authors: Roy M M
Published: June 2008

This study investigated the effect of an oxidation catalyst on odorous emissions in a direct-injection diesel engine at idling. In cold or low-temperature idling, where engines are started from cold condition at ambient temperatures, the effectiveness of the oxidation catalyst to reduce total hydrocarbons (THCs) and aldehydes is low owing to the low catalyst temperatures, and the odour reduction is insignificant. In hot or high-temperature idling, where exhaust temperatures exceed 200°C, THCs and aldehydes are reduced by more than 90 per cent and the odour reduction is more than one point, a significant odour reduction. Below a catalyst temperature of 200°C, objectionable exhaust odour appears.

The gasoline engine also emits a strong exhaust odour when the catalyst condition is poor or there is a mismatch of air—fuel ratio. The effect of a three-way catalyst on the exhaust odour was investigated in a gasoline engine. In rich engine operation condition, there are more THCs, carbon monoxide (CO), and nitrogen oxides (NO x) before the catalyst. After the catalyst in this condition, the THCs, CO, and NO x are significantly reduced, but there is a very sharp and unpleasant odour of ammonia, which is produced inside the catalyst owing to the reduction of NO x.
Photochromic Properties of -Cyclodextrin Dimer Linked by Dithienylethene
Authors: Hu Hui-yuan , Zhang Zhi-ping , Meng Xiang-ming , Zhu Man-zhou , Guo Qing-xiang
Published: June 2008

A -cyclodextrin dimer tethered by photoswitchable dithienylethene moieties was synthesized as a potentially tunable receptor. The dimer exhibits pronounced photochromic properties. Irradiation of the dimer in open form with UV light at 254 nm resulted in immediate photocyclization to the pink closed form; the colorless open form could be regenerated by irradiation with visible light of wavelength >460 nm. The reaction kinetics of the forward photoprocess were also studied. To investigate the binding ability of the dimer in open and closed forms, a fluorescence titration was performed. It was found that the stability constant for the binding of TSPP (meso-tetrakis (4-sulfonatophenyl)porphyrin) by the closed form of the dimer is a factor of 5 higher than that of the open form.
Barrier Height Effect on Cl+H2(D2) Reaction
Authors: Xie Ting-xian , Shi Ai-min
Published: June 2008

Three-dimensional time-dependent quantum wave packet calculation was performed to study the reaction dynamics of Cl+H2(D2) on two potential energy surfaces (CW PESs). The first CW PES is with spin-orbit correction; the second is without spin-orbit correction. The integral cross-section and reaction probability as a function of collision energy are calculated in the collision energy range of 0.1 eV to 1.4 eV. For reaction of Cl with D2, the reaction section with spin-orbit correction has a shift toward the high energy because the barrier height increases. As for the reaction of Cl with H2 at low collision energy, it is more reactive on the PES with spin-orbit correction than on the low barrier height PES without spin-orbit correction, due to the tunnel effect for the reaction of the Cl with H2. When the collision energy is higher than 0.7 eV, the reactivity on the low barrier height PES is larger than that on the high barrier height PES. It is believed that the barrier height plays a very important role in the reactivity of Cl with (H2, D2). For the Cl+H2 reaction the barrier width is also very important because of the tunneling effect.
Fractal Study of Mesoporous Structure in Water Molecular Condensed System
Authors: Wang Li , Yang Ya-Jiang
Published: June 2008

Bis-(4-stearoylaminophenyl) ether (BSADE) can aggregate and self-assemble in water. Transmission electron microscopy (TEM) indicated that the morphology of BSADE aggregates in water was entanglement and thin fiber-like, and that a three dimensional network structure was formed. Water molecules were entrapped in this three dimensional network structure and formed a new type of condensed system (so-called water molecular gel). Water molecular gel is a typical mesoporous material which can be characterized by the fractal dimension D. Using gas adsorption method along with measurement of porosity and specific surface area, the fractal dimension D of the complicated pores was 2.1-2.2 for this water molecular gel. Using viscosity method and the Cayley fractal tree, the fractal dimension D of the fiber-like three dimensional network was determined to be 1.98. The formation process of water molecular gel can be described as nucleation followed by a repeated growing and branching cycle.
Kinetics of Reactions of CCN Radical with Alcohols
Authors: Zhu Zhi-qiang , Ji Min , Zhang Shao-hua , Pei Lin-sen , Chen Yang
Published: June 2008

The reaction kinetics of cyanomethylidyne radical, CCN(X2), with a series of primary alcohols were studied at about 1.33 kPa total pressure and room temperature using pulsed laser photolysis/laser-induced fluorescence (LP/LIF) technique. The CCN radical was produced via laser photolysis of CCl3CN with the fourth harmonic output of a Nd: YAG laser (266 nm). The relative concentration of the CCN(X2) radical was monitored by LIF in the (0, 0) band of the CCN(A2 X2) transition at 470.9 nm. Under pseudo-first-order conditions, the reaction rate constants of CCN(X2) with a series of primary alcohol molecules (n-CnH2n+1OH, n=1-6) were determined by measuring the time evolution of the relative concentration of CCN(X2i). The measured rate constants increased monotonously with the number of carbon atoms in the alcohols, and the values for reactions of CCN(X2) with alcohols were larger than those for reactions of CCN(X2) with alkanes (C1-C5). Based on the bond dissociation energies and linear free energy correlations, it was believed that the reactions of CCN(X2) with alcohols proceeded via a hydrogen abstraction mechanism that was analogous to CCN(X2) with alkanes. The experimental results indicated that the H atoms on the C-H bonds were activated at the presence of the OH group in alcohol molecules and the hydrogen abstraction from the C-H bonds in the alcohol molecules was the dominant reaction pathway. The relation between the rate constants and the long-distance attractive potentials between the CCN radical and the alcohol molecules was discussed.
Electronic Structure and Photophysical Properties of 2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine
Authors: Li Yuan-zuo , Sun Yu , Li Yong-qing , Ma Feng-cai
Published: June 2008

Electronic structure and photophysical properties of 2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine are studied theoretically with quantum chemical methods as well as 2D site and 3D cube representations. The theoretical results reveal that the first excited state is an intramolecular charge transfer excited state. The change in dipole moment for the first excited state of the excitation is fitted, and the calculated result the change in dipole moment =6.40 D is consistent with the experimental result =6.90 D. The polarizability is also fitted. The large changes in dipole moment and the polarizability of the excitation show that S1 is of large nonlinear optical (NLO) effect. The NLO will promote efficient two-photon-absorption cross sections. The excited state properties of dpbt with different external electronic fields are also discussed theoretically.
Thermoelasticity of MgO at High Pressures
Authors: Liu Zi-jiang , Sun Xiao-wei , Ge Su-hong , Wu Hai-ying , Zhang Xiu-lu , Yang Xiang-dong
Published: June 2008

The thermoelastic properties of MgO over a wide range of pressure and temperature are studied using the first-principles plane wave pseudopotential method within the generalized gradient approximation. It is shown that MgO remains in the B1 (NaCl) structure at all pressures existing within the Earth, and transforms into the CsCl-type structure at 397 GPa. The athermal elastic moduli of MgO are calculated, as a function of pressure up to 150 GPa. The calculated results are in excellent agreement with experimental data at zero pressure and compare favorably with other pseudopotential predictions over the pressure regime studied. MgO is found to be highly anisotropic in its elastic properties, with the magnitude of the anisotropy first decreasing between 0 and 20 GPa and then increasing from 20 GPa to 150 GPa. The Cauchy condition is found to be strongly violated in MgO, reflecting the importance of noncentral many-body forces. The thermodynamic properties of MgO are consistent with the experimental data at ambient condition.