bluuebunny/crossref_metadata_2025 huggingface dataset:
Functions of the Clostridium acetobutylicium FabF and FabZ proteins in unsaturated fatty acid biosynthesis
Authors: Zhu Lei , Cheng Juanli , Luo Biao , Feng Saixiang , Lin Jinshui , Wang Shengbin , Cronan John E , Wang Haihong
Published: June 2009

Background

The original anaerobic unsaturated fatty acid biosynthesis pathway proposed by Goldfine and Bloch was based on in vivo labeling studies in Clostridium butyricum ATCC 6015 (now C. beijerinckii) but to date no dedicated unsaturated fatty acid biosynthetic enzyme has been identified in Clostridia. C. acetobutylicium synthesizes the same species of unsaturated fatty acids as E. coli, but lacks all of the known unsaturated fatty acid synthetic genes identified in E. coli and other bacteria. A possible explanation was that two enzymes of saturated fatty acid synthesis of C. acetobutylicium, FabZ and FabF might also function in the unsaturated arm of the pathway (a FabZ homologue is known to be an unsaturated fatty acid synthetic enzyme in enterococci).

Results

We report that the FabF homologue located within the fatty acid biosynthetic gene cluster of C. acetobutylicium functions in synthesis of both unsaturated fatty acids and saturated fatty acids. Expression of this protein in E. coli functionally replaced both the FabB and FabF proteins of the host in vivo and replaced E. coli FabB in a defined in vitro fatty acid synthesis system. In contrast the single C. acetobutylicium FabZ homologue, although able to functionally replace E. coli FabZ in vivo and in vitro, was unable to replace FabA, the key dehydratase-isomerase of E. coli unsaturated fatty acid biosynthesis in vivo and lacked isomerase activity in vitro.

Conclusion

Thus, C. acetobutylicium introduces the double of unsaturated fatty acids by use of a novel and unknown enzyme.
Identification and expression analysis of WRKY transcription factor genes in canola (Brassica napus L.) in response to fungal pathogens and hormone treatments
Authors: Yang Bo , Jiang Yuanqing , Rahman Muhammad H , Deyholos Michael K , Kav Nat NV
Published: June 2009

Background

Members of plant WRKY transcription factor families are widely implicated in defense responses and various other physiological processes. For canola (Brassica napusL.), no WRKY genes have been described in detail. Because of the economic importance of this crop, and its evolutionary relationship toArabidopsis thaliana, we sought to characterize a subset of canolaWRKYgenes in the context of pathogen and hormone responses.

Results

In this study, we identified 46WRKYgenes from canola by mining the expressed sequence tag (EST) database and cloned cDNA sequences of 38BnWRKYs. A phylogenetic tree was constructed using the conserved WRKY domain amino acid sequences, which demonstrated that BnWRKYs can be divided into three major groups. We further comparedBnWRKYsto the 72WRKYgenes fromArabidopsisand 91WRKYfrom rice, and we identified 46 presumptive orthologs ofAtWRKYgenes. We examined the subcellular localization of four BnWRKY proteins using green fluorescent protein (GFP) and we observed the fluorescent green signals in the nucleus only.

The responses of 16 selectedBnWRKYgenes to two fungal pathogens,Sclerotinia sclerotiorumandAlternaria brassicae, were analyzed by quantitative real time-PCR (qRT-PCR). Transcript abundance of 13BnWRKYgenes changed significantly following pathogen challenge: transcripts of 10WRKYs increased in abundance, twoWRKYtranscripts decreased after infection, and one decreased at 12 h post-infection but increased later on (72 h). We also observed that transcript abundance of 13/16BnWRKYgenes was responsive to one or more hormones, including abscisic acid (ABA), and cytokinin (6-benzylaminopurine, BAP) and the defense signaling molecules jasmonic acid (JA), salicylic acid (SA), and ethylene (ET). We compared these transcript expression patterns to those previously described for presumptive orthologs of these genes inArabidopsisand rice, and observed both similarities and differences in expression patterns.

Conclusion

We identified a set of 13BnWRKYgenes from among 16BnWRKYgenes assayed, that are responsive to both fungal pathogens and hormone treatments, suggesting shared signaling mechanisms for these responses. This study suggests that a large number of BnWRKY proteins are involved in the transcriptional regulation of defense-related genes in response to fungal pathogens and hormone stimuli.
Mediated, moderated and direct effects of country of residence, age, and gender on the cognitive and social determinants of adolescent smoking in Spain and the UK: a cross-sectional study
Authors: Markham Wolfgang A , Lopez Maria Luisa , Aveyard Paul , Herrero Pablo , Bridle Christopher , Comas Angel , Charlton Anne , Thomas Hywel
Published: June 2009

Background

European trans-national adolescent smoking prevention interventions based on social influences approaches have had limited success. The attitudes-social influences-efficacy (ASE) model is a social cognition model that states smoking behaviour is determined by smoking intention which, in turn, is predicted by seven ASE determinants; disadvantages, advantages, social acceptance, social norms, modelling, perceived pressure, self-efficacy. Distal factors such as country of residence, age and gender are external to the model. The ASE model is, thus, closely related to the Theory of Planned Behaviour. This study assessed the utility of the ASE model using cross-sectional data from Spanish and UK adolescents.

Methods

In 1997, questionnaires were simultaneously administered to Spanish (n = 3716) and UK adolescents (n = 3715) who were considered at high risk of smoking. Participants' age, gender, smoking intentions and ASE determinant scores were identified and linear regression analysis was used to examine the mediated, moderated and direct effects of country of residence, age and gender on participants' smoking intentions.

Results

All UK participants were aged 12 or 13 and most Spanish participants were aged between 12 and 14 (range 12–16 years). Amongst 12 and 13 year olds, regular smoking was more common in Spain. Almost half the participants were female (47.2% in Spain; 49.9% in the UK). Gender did not vary significantly according to age.

The distribution of ASE determinant scores varied by country and predicted intention. The influence of each ASE determinant on intention was moderated by country. Country had a large direct influence on intention (1.72 points on a 7 point scale) but the effects of age and gender were mediated by the ASE determinants.

The findings suggest resisting peer pressure interventions could potentially influence smoking amongst UK adolescents but not Spanish adolescents. Interventions that promote self-efficacy, on the other hand, would possibly have a greater influence on smoking amongst Spanish adolescents.

Conclusion

The ASE model may not capture important cultural factors related to adolescent smoking and the relative contribution of particular ASE determinants to adolescent smoking intentions may differ between countries. Future European trans-national adolescent smoking prevention programmes may benefit from greater undestanding of country-level cultural norms.
Factors associated with low bone mass in the hemodialysis patients – a cross-sectional correlation study
Authors: Huang Guey-Shiun , Chu Tzong-Shinn , Lou Meei-Fang , Hwang Shiow-Li , Yang Rong-Sen
Published: June 2009

Background

Low bone mass is common in end-stage renal disease patients, especially those undergoing hemodialysis. It can lead to serious bone health problems such as fragility fractures. The purpose of this study is to investigate the risk factors of low bone mass in the hemodialysis patients.

Methods

Sixty-three subjects on hemodialysis for at least 6 months were recruited from a single center for this cross-sectional study. We collected data by questionnaire survey and medical records review. All subjects underwent a bone mineral density (BMD) assay with dual-energy x-ray absorptiometry at the lumbar spine and right hip. Data were statistically analyzed by means of descriptive analysis, independent t test and one way analysis of variance for continuous variables, Pearson product-moment correlation to explore the correlated factors of BMD, and stepwise multiple linear regression to identify the predictors of low bone mass.

Results

Using WHO criteria as a cutoff point, fifty-one subjects (81%) had a T-score lower than -1, of them 8 subjects (13%) had osteoporosis with the femoral neck most commonly affected. Regarding risk factors, age, serum alkaline phosphatase (ALP) level, and intact parathyroid hormone (iPTH) level had significant negative correlations with the femoral neck and lumbar spine BMD. On the other hand, serum albumin level, effective exercise time, and body weight (BW) had significant positive correlations with the femoral neck and lumbar spine BMD. Age, effective exercise time, and serum albumin level significantly predicted the femoral neck BMD (R2 × 0.25), whereas BW and the ALP level significantly predicted the lumbar spine BMD (R2 × 0.20).

Conclusion

This study showed that advanced age, low BW, low serum albumin level, and high ALP and iPTH levels were associated with a low bone mass in the hemodialysis patients. We suggest that regular monitoring of the femoral neck BMD, maintaining an adequate serum albumin level and BW, and undertaking an exercise program are important to improve bone health in the patients undergoing hemodialysis.
Identification of ERβ1 and ERβ2 in human seminoma, in embryonal carcinoma and in their adjacent intratubular germ cell neoplasia
Authors: Rago Vittoria , Romeo Francesco , Giordano Francesca , Ferraro Aurora , Andò Sebastiano , Carpino Amalia
Published: June 2009

Background

Estrogens exert a role on germ cell physiology of normal human testis through the mediation of the estrogen receptor (ER) beta subtypes. Epidemiological studies evidenced an increased incidence of testicular germ cell cancer after elevated pre-natal estrogen exposure but the expression of estrogen receptors in these testicular neoplasms has not been well elucidated.

Methods

Immunohistochemistry and Western blot analysis were used to investigate the expression of three distinct ER isoforms, ERalpha, ERbeta1, and ERbeta2 in paraffin-embedded tissues from seminomas and embryonal carcinomas, which are the most common testicular germ cell tumours.

Results

Neoplastic cells of all specimens revealed a positive ERbeta1 and ERbeta2 immunoreactivity, while the ERalpha signal was undetectable. A similar pattern of estrogen receptor immunostaining was also observed in the malignant germ cells of intratubular germ cell neoplasia, adjacent to testicular cancers. Western blot analysis of tumour extracts revealed two immunoreactive bands, a 59 kDa band for ERbeta1 and a 53 kDa band for ERbeta2.

Conclusion

A variable ERbeta expression was previously reported in testicular germ cell tumours and, particularly, an ERbeta down-regulation was evidenced in seminoma and embryonal carcinoma. Conversely, the current study has clearly identified ERbeta1 and ERbeta2 in the neoplastic cells of seminoma and embryonal carcinoma, as well as in the malignant cells of their common pre-invasive precursor, intratubular germ cell neoplasia. Therefore, our findings suggest that ERbeta1, together with a possible ERbeta2 contribute, can mediate estrogen action in both early and late neoplastic testicular germ cells, not confirming the previously hypothesized antiproliferative effect of ERbeta on male gonadal cells.
Rationale, design, and baseline characteristics of the Acetylcystein for Contrast-Induced nephropaThy (ACT) Trial: a pragmatic randomized controlled trial to evaluate the efficacy of acetylcysteine for the prevention of contrast-induced nephropathy
Authors:   The ACT Trial Investigators
Published: June 2009

Background

Aceltylcysteine has been evaluated in several small trials as a means of reducing the risk of contrast-induced nephropathy (CIN), however systematic reviews of these studies do not provide conclusive answers. Therefore, a large randomized controlled trial (RCT) is needed to provide a reliable answer as to whether acetylcysteine is effective in decreasing the risk of CIN in high-risk patients undergoing angiographic procedures.

Methods

ACT is a RCT of acetylcysteine versus placebo in 2,300 patients at-risk for CIN undergoing an intravascular angiographic procedure. The randomization list will be concealed. Participants, health care staff, investigators and outcome assessors will be blinded to whether patients receive acetylcysteine or placebo. All analysis will follow the intention-to-treat principle. The study drugs (acetylcysteine 1200 mg or placebo) will be administered orally twice daily for two doses before and two doses after the procedure. The primary outcome is the occurrence of CIN, defined as a 25% elevation of serum creatinine above baseline between 48 and 96 hours after angiography.

Discussion

The first patient entered the trial on September, 2008. Up to April 7, 2009, 810 patients had been included in 35 centers. The mean age was 69 (Standard deviation: 10), 18% had a baseline serum creatinine >1.5 mg/dL, 57% were diabetics and 13% had a history of heart failure. The ongoing ACT Trial is the largest multicentre RCT that will determine whether acetylcysteine is effective in decreasing the risk of CIN in patients at risk undergoing angiography.

Trial registration

Clinicaltrials.gov NCT00736866
A multicenter review of deep venous thrombosis prophylaxis practice patterns for blunt hepatic trauma
Authors: Datta Indraneel , Ball Chad G , Rudmik Lucas R , Paton-Gay Damian , Bhayana Deepak , Salat Peter , Schieman Colin , Smith Dean F , vanWijngaarden-Stephens Mary , Kortbeek John B
Published: June 2009

Background

Non-operative management of blunt hepatic trauma is successful in the majority of hemodynamically stable patients. Due to the risk of recurrent hemorrhage, pharmacologic deep venous thrombosis (DVT) prophylaxis is often delayed. The optimal timing of prophylaxis is unclear. A multi-centre, retrospective review of patients with blunt hepatic injuries presenting between 2000 and 2004 was performed. All patients had an ISS ≥ 12 and a CT scan confirming hepatic trauma. Patients were categorized into: (1) early DVT prophylaxis (≤ 48 hrs of admission), (2) delayed prophylaxis (>48 hrs), and (3) no prophylaxis.

Methods and results

Thirty-seven (25%) and 45 (42%) patients received early and delayed DVT prophylaxis respectively. The remainder (32%) received none. Mean hepatic injury grades were lower in the early prophylaxis group (II) compared to the delayed and no prophylaxis cohorts (III)(p = 0.002). The number of patients requiring post-admission blood transfusions was highest in the delayed group (44%) compared to the early (26%) and no prophylaxis (6%) groups (p = 0.03). No patient in the early prophylaxis cohort developed a DVT or required delayed angiographic or operative intervention. Two patients in the delayed group failed non-operative management. Eight (18%) patients in the delayed group developed a clinically significant DVT; 1 (2%) progressed to a PE.

Conclusion

Practice patterns indicate that chemical DVT prophylaxis initiated within 48 hours of admission may be safe in patients with significant blunt hepatic trauma. Delays in prevention result in venothromboembolic events, but not in fewer blood transfusions or a decreased need for subsequent angiographic or operative therapies.
Molecular prognostic markers for adult acute myeloid leukemia with normal cytogenetics
Authors: Gregory Tara K , Wald David , Chen Yichu , Vermaat Johanna M , Xiong Yin , Tse William
Published: June 2009

Acute myeloid leukemia (AML) is a heterogenous disorder that results from a block in the differentiation of hematopoietic progenitor cells along with uncontrolled proliferation. In approximately 60% of cases, specific recurrent chromosomal aberrations can be identified by modern cytogenetic techniques. This cytogenetic information is the single most important tool to classify patients at their initial diagnosis into three prognostic categories: favorable, intermediate, and poor risk. Currently, favorable risk AML patients are usually treated with contemporary chemotherapy while poor risk AML patients receive allogeneic stem cell transplantation if suitable stem cell donors exist. The largest subgroup of AML patients (~40%) have no identifiable cytogenetic abnormalities and are classified as intermediate risk. The optimal therapeutic strategies for these patients are still largely unclear. Recently, it is becoming increasingly evident that it is possible to identify a subgroup of poorer risk patients among those with normal cytogenic AML (NC-AML). Molecular risk stratification for NC-AML patients may be possible due to mutations of NPM1, FLT3, MLL, and CEBPα as well as alterations in expression levels of BAALC, MN1, ERG, and AF1q. Further prospective studies are needed to confirm if poorer risk NC-AML patients have improved clinical outcomes after more aggressive therapy.
ENREGISTERMENT, COMMODIFICATION, AND HISTORICAL CONTEXT: “GEORDIE” VERSUS “SHEFFIELDISH”
Authors: Beal Joan C.
Published: June 2009

This article examines a range of texts from nineteenth-century Newcastle and Sheffield, both in the north of England, to demonstrate how the urban dialects of these cities, known respectively as “Geordie” and “Sheffieldish,” became enregistered in this period. Features that were actually more widespread in the north of England and in Scotland were “claimed” as unique to each of these new urban dialects, and in each case, a repertoire of features emerged that continues to be cited and indeed used by speakers and writers today, albeit often in performative contexts. The article goes on to consider how awareness of a distinct “Geordie” accent/dialect arrived much earlier and became more widespread than that of “Sheffieldish” and how this is reflected in the commodification of the former but not the latter.
PITTSBURGHESE SHIRTS: COMMODIFICATION AND THE ENREGISTERMENT OF AN URBAN DIALECT
Authors: Johnstone Barbara
Published: June 2009

This article considers a type of material artifact that circulates ideas about regional speech in the United States: T-shirts bearing words and phrases thought to be unique to Pittsburgh, Pennsylvania. I argue that Pittsburghese shirts, seen for themselves and in the context of their production, distribution, and consumption, are part of a process leading to the creation and focusing of the idea that there is a Pittsburgh dialect. To describe how particular locally hearable forms have become linked with the city, I invoke Asif Agha's concept of “enregisterment.” To understand why this has happened at the time and in the way it has, I draw on Arjun Appadurai's model of the “commodity situation.” I suggest that Pittsburghese shirts contribute to dialect enregisterment in at least four ways: they put local speech on display, they imbue local speech with value, they standardize local speech, and they link local speech with particular social meanings.
Rac3 inhibits adhesion and differentiation of neuronal cells by modifying GIT1 downstream signaling
Authors: Hajdo-Milasinovic Amra , van der Kammen Rob A. , Moneva Zvezdana , Collard John G.
Published: June 2009

Rac1 and Rac3 are highly homologous regulatory proteins that belong to the small GTPases of the Rho family. Previously, we showed that Rac3 induces cell rounding and prevents neuronal differentiation, in contrast to its close relative Rac1, which stimulates cell spreading and neuritogenesis. To explain these opposing effects, we investigated whether Rac1 and Rac3 interact with different proteins. Here, we show that both Rac1 and Rac3 interact with GIT1, a multifunctional Arf-GAP protein, which regulates cell-matrix adhesion, cell spreading and endocytosis. However, in contrast to Rac1, the Rac3-GIT1 interaction is not mediated by βPix. Interestingly, Rac3 expression severely attenuates the interaction between GIT1 and paxillin, accompanied by defective paxillin distribution, focal adhesion formation and disturbed cell spreading. Moreover, in Rac3-expressing cells, Arf6 activity is strongly reduced and the Arf6-GAP activity of GIT1 is required for Rac3 downstream signaling. Indeed, expression of wild-type Arf6 or the Arf6-GEF ARNO induced cell spreading in the otherwise rounded Rac3-expressing cells. Our data suggest that Rac3 and Rac1 oppose each other's function by differently modulating GIT1 signaling. Rac1 induces adhesion and differentiation by activating PAK1 and stimulating the GIT1-paxillin interaction, whereas Rac3 blocks this interaction and inactivates Arf6 by stimulating the GAP function of GIT1, thereby preventing cell spreading and differentiation.
Inactivation of the C. elegans lipin homolog leads to ER disorganization and to defects in the breakdown and reassembly of the nuclear envelope
Authors: Golden Andy , Liu Jun , Cohen-Fix Orna
Published: June 2009

The nuclear envelope (NE) is a dynamic structure, undergoing periods of growth, breakdown and reassembly during the cell cycle. In yeast, altering lipid synthesis by inactivating the yeast homolog of lipin, a phosphatidic acid phosphohydrolase, leads to disorganization of the peripheral ER and abnormal nuclear shape. These results suggest that lipid metabolism contributes to NE dynamics; however, since yeast undergo closed mitosis, the relevance of these observations to higher eukaryotes is unclear. In mammals, lipin has been implicated in adipose tissue differentiation, insulin resistance, lipid storage and obesity, but the underlying cellular defects caused by altering lipin levels are not known. Here, we identify the Caenorhabditis elegans lipin homolog (LPIN-1) and examine its affect on NE dynamics. We find that downregulating LPIN-1 by RNAi results in the appearance of membrane sheets and other abnormal structures in the peripheral ER. Moreover, lpin-1 RNAi causes defects in NE breakdown, abnormal chromosome segregation and irregular nuclear morphology. These results uncover cellular processes affected by lipin in metazoa, and suggest that lipid synthesis has a role in NE dynamics.
CDK2 is required for proper homologous pairing, recombination and sex-body formation during male mouse meiosis
Authors: Viera Alberto , Rufas Julio S. , Martínez Inés , Barbero José L. , Ortega Sagrario , Suja José A.
Published: June 2009

Cyclin-dependent kinase 2 (CDK2) was assumed to be essential in the mammalian cell cycle both at the G1-S transition and throughout the S phase. Interestingly, ablation of Cdk2 in mice does not have substantial consequences for embryonic or postnatal development, but both males and females are infertile. In the present study, we have analysed the meiotic alterations leading to infertility in Cdk2–/– male mice. We have studied the distribution and dynamics of several proteins related to meiosis progression, such as synaptonemal complex proteins, cohesin complexes, and centromere-, telomere- and recombination-related proteins. Cdk2–/– spermatocytes show an incomplete chromosome pairing, an extensive non-homologous synapsis and arrest at a pachytene-like stage with unrepaired programmed double-strand breaks. In these spermatocytes, some telomeres do not attach to the nuclear envelope, and sex chromosomes do not form a sex body. Our data demonstrate an unpredicted participation of CDK2 in the accurate pairing and recombination between homologues during mammalian meiosis.
An integral protein of the inner nuclear membrane localizes to the mitotic spindle in mammalian cells
Authors: Buch Charlotta , Lindberg Robert , Figueroa Ricardo , Gudise Santhosh , Onischenko Evgeny , Hallberg Einar
Published: June 2009

Here, we characterize a transmembrane protein of the nuclear envelope that we name spindle-associated membrane protein 1 (Samp1). The protein is conserved in metazoa and fission yeast and is homologous to Net5 in rat and Ima1 in Schizosaccharomyces pombe. We show that, in human cells, the protein is a membrane-spanning polypeptide with an apparent molecular mass of 43 kDa. This is consistent with a predicted polypeptide of 392 amino acids that has five transmembrane segments and its C-terminus exposed to the nucleoplasm. During interphase, Samp1 was specifically distributed in the inner nuclear membrane. Post-transcriptional silencing of Samp1 expression resulted in separation of centrosomes from the nuclear envelope, indicating that it is functionally connected to the cytoskeleton. At the onset of mitosis, most of the protein dispersed out into the ER, as expected. However, during mitosis, a significant fraction of the protein specifically localized to the polar regions of the mitotic spindle. We demonstrate for the first time, in human cells, the existence of a membranous structure overlapping with the mitotic spindle. Interestingly, another integral inner nuclear membrane protein, emerin, was absent from the spindle-associated membranes. Thus, Samp1 defines a specific membrane domain associated with the mitotic spindle.
A limit load solution for a thick-walled cylinder with a fully circumferential crack under axial tension
Authors: Budden P J , Lei Y
Published: June 2009

Limit loads for a thick-walled cylinder with an internal or external fully circumferential surface crack under pure axial load are derived on the basis of the von Mises yield criterion. The solutions reproduce the existing thin-walled solution when the ratio between the cylinder wall thickness and the inside radius tends to zero. The solutions are compared with published finite element limit load results for an elastic–perfectly plastic material. The comparison shows that the theoretical solutions are conservative and very close to the finite element data.
Equivalent fuel consumption optimal control of a series hybrid electric vehicle
Authors: Gao J-P , Zhu G-M G , Strangas E G , Sun F-C
Published: June 2009

Improvements in hybrid electric vehicle fuel economy with reduced emissions strongly depend on their supervisory control strategy. In order to develop an efficient real-time supervisory control strategy for a series hybrid electric bus, the proposed equivalent fuel consumption optimal control strategy is compared with two popular strategies, thermostat and power follower, using backward simulations in ADVISOR. For given driving cycles, global optimal solutions were also obtained using dynamic programming to provide an optimization target for comparison purposes. Comparison simulations showed that the thermostat control strategy optimizes the operation of the internal combustion engine and the power follower control strategy minimizes the battery charging and discharging operations which, hence, reduces battery power loss and extends the battery life. The equivalent fuel consumption optimal control strategy proposed in this paper provides an overall system optimization between the internal combustion engine and battery efficiencies, leading to the best fuel economy.
Investigation into the influence of environmental conditions on power system ratings
Authors: Michiorri A , Taylor P C , Jupe S C E , Berry C J
Published: June 2009

This article presents research that seeks to assist distribution network operators in the adoption of real-time thermal rating (RTR) systems. The exploitation of power system rating variations is challenging because of the complex nature of environmental conditions such as wind speed. The adoption of an RTR system may overcome this challenge and offers perceived benefits such as increased distributed generation (DG) accommodation and avoidance of component damage or premature ageing. Simulations, using lumped parameter component models, are used to investigate the influence of environmental conditions on overhead line, electric cable, and power transformer ratings. Key findings showed that the average rating of overhead lines, electric cables, and power transformers ranged from 1.70 to 2.53, 1.00 to 1.06, and 1.06 to 1.10 times the static rating, respectively. Since overhead lines were found to have the greatest potential for rating exploitation, the influence of environmental conditions on four overhead line types was investigated and it was shown that the value of an RTR system is location dependent. Furthermore, the additional annual energy yield from DG that could potentially be accommodated through deployment of an RTR system was found to be 54 per cent for the case considered.
The capability of energy storage systems to damp power system oscillations
Authors: Du W , Wang H F , Xiao L , Dunn R
Published: June 2009

This article presents a novel analytical method for studying the capability of an energy storage system (ESS) installed in a power system to damp power system oscillations. The proposed method is based on the well-known equal-area criterion and linearized small-signal stability analysis. In the article, the proposed method is presented generally for the analysis of damping a power oscillation along a transmission line in the power system. The method is then used to study damping power system oscillations in a single-machine infinite-bus power system installed with a shunt-connected ESS. Many useful analytical conclusions are obtained, which clearly and simply explains why and how the ESS can effectively suppress power system oscillations. Computational results and nonlinear simulation of an example power system installed with a battery energy storage system (BESS) are given in the article to demonstrate and confirm the analytical conclusions obtained. Application of the proposed method in a more complicated case of multi-machine power systems and an issue of limitation of capacity of ESS in the applications are discussed briefly at the end of the article.
Linear approximant-based metaheuristic proportional-integral-derivative controller for a neutral time delay central heating system
Authors: Koumboulis F N , Kouvakas N D , Paraskevopoulos P N
Published: June 2009

For a test-case central heating plant, modelled as a non-linear neutral time delay system, a metaheuristic proportional-integral-derivative (PID) control scheme is proposed to control the temperature of the room using as a sole actuatable input the energy supplied to the boiler. The control scheme is based on a neutral time delay description of the linearized approximation of the process. The linearization is tested using a Euclidian norm type of error, with emphasis on the performance variable of the system, to show that it is an accurate approximation of the original process for a wide range of variables of the plant. The performance of the closed-loop system is examined via simulation experiments.
Surface defects effects on bearing dynamics
Authors: Ashtekar A , Sadeghi F , Stacke L-E
Published: June 2009

Influence of race defects on the motions of bearing components (i.e. inner and outer races, cage, and balls) was investigated using a six degrees of freedom dynamic model for deep groove and angular contact ball bearings. Surface defects such as dents and bumps on bearing surfaces cause the elements (balls and cage) of bearings to vibrate and impact the inner and outer races. To model the effects of surface defects on bearing dynamics, the superposition principle was used to include the effects of a dent or bump on bearing dynamics. A bump having a general geometry was modelled as an equivalent ellipsoid in contact with the original bearing components geometry while a dent was modelled as an equivalent ellipsoidal depression on the bearing surface in contact with bearing component. Therefore, the net forces acting on the contacting body is superposition of forces acting on the bodies without any defect and forces corresponding to defect alone. This approach was also used to investigate and model the effects of debris contaminants on bearing performance. The effects of the debris are calculated similar to bumps with an exception that debris is free to move within the bearing component domain. The results indicate that surface defects and irregularities such as dents and bumps have a significant effect on bearing motion and forces. The results also demonstrate that a single defect can affect the forces and motion throughout the entire bearing and on all bearing components.
Dynamic mechanical properties of polymer-lining and their effect on coefficient of friction
Authors: Peng Y X , Zhu Z C , Chen G A
Published: June 2009

To obtain the dynamic and thermomechanical properties of polymer-lining and their effect on coefficient of friction (COF) between lining and wire rope, dynamic mechanical ana-lysis (DMA) and friction experiment were performed on the polymer-linings of GM-3 and K25. The effects of temperature and frequency on storage modulus ( E1), loss modulus ( E2), and loss factor (tanΔ) were obtained by DMA based on the theory of viscoelasticity. It was observed that the values of E1 increased with increasing frequency at−20–375 °C, while the values of E2 and tanΔ increased with frequency from Tg (glass-transition temperature) and reversed at higher temperature. Moreover, friction experiments were conducted on a special friction tester at different surrounding temperatures to measure COF of K25 and GM-3. It is found that the COF increases linearly with the loss factor, which can give good explanation for why COF increases with low sliding speed. Therefore, it is feasible and effective for increasing the loss factor or decreasing the storage modulus to improve polymer-lining's COF, which can also supply theoretical support for developing new lining with high tribological property.
Four-bar motion generation with elasticity constraints and optimization
Authors: Al-Smadi Y M , Russell K , Sodhi R S
Published: June 2009

In conventional planar four-bar motion generation, all mechanism links are assumed rigid or non-deforming. Although the assumption of link rigidity in kinematic synthesis may be generally appropriate and often practiced, a statically loaded planar four-bar mechanism will undergo a degree of elastic deflection, particularly the crank and follower links. In this work, a non-linear optimization problem is formulated for planar four-bar motion generation that considers an applied coupler force and corresponding crank static torque, crank transverse deflection, and follower buckling. The output from the non-linear optimization problem – mechanism fixed and moving pivot loci – are input for a search algorithm that down selects a mechanism solution that satisfies transmission angle conditions, Grashof conditions, and a mechanism compactness condition. The final output of the presented method is planar four-bar motion generator that approximates prescribed coupler poses with satisfactory crank deflection and without follower buckling and also satisfies conditions for link rotatability, transmission angle and compactness.
Effect of silver ring splints on hand dexterity and grip strength in patients with rheumatoid arthritis: an observational pilot study
Authors: Spicka Caroline , Macleod Christina , Adams Jo , Metcalf Cheryl
Published: June 2009

Background

Deformities of the proximal interphalangeal joints (PIPJ) of the hand are common in patients with rheumatoid arthritis. Three-point ring splints are one of several conservative options for treating such deformities.

Methods

This observational pilot study assessed the impact of PIPJ silver ring splints (SRS) on dexterity and handgrip strength in individuals with rheumatoid arthritis. Dexterity and handgrip were measured using two standardized outcome tools, the Nine Hole Peg Test and the MIE digital grip analyser. Eight individuals who routinely wore individually tailored SRS from one rheumatology occupational therapy department were recruited into the study. Hand dexterity and grip strength was tested with and without the SRS in situ.

Results

Although differences in bilateral dexterity and handgrip strength results did not reach statistical significance ( P > 0.05) in this sample, there was a trend for dexterity and grip strength to slightly improve when SRS were worn.

Conclusions

Further research is needed to evaluate the effect of SRS on hand function especially its long-term effect on deformities.
Worst-Case Analysis for a General Class of Online Lot-Sizing Heuristics
Authors: Van den Heuvel Wilco , Wagelmans Albert P. M.
Published: June 2009

In this paper, we analyze the worst-case performance of heuristics for the classical economic lot-sizing problem with time-invariant cost parameters. We consider a general class of online heuristics that is often applied in a rolling-horizon environment. We develop a procedure to systematically construct worst-case instances for a fixed time horizon and use it to derive worst-case problem instances for an infinite time horizon. Our analysis shows that any online heuristic has a worst-case ratio of at least 2.
Copula-Based Multivariate Input Models for Stochastic Simulation
Authors: Biller Bahar
Published: June 2009

As large-scale discrete-event stochastic simulation becomes a tool that is used routinely for the design and analysis of stochastic systems, the need for input-modeling support with the ability to represent complex interactions and interdependencies among the components of multivariate time-series input processes is more critical than ever. Motivated by the failure of independent and identically distributed random variables to represent such input processes, a comprehensive framework called Vector-Autoregressive-To-Anything (VARTA) has been introduced for multivariate time-series input modeling. Despite its flexibility in capturing a wide variety of distributional shapes, we show that VARTA falls short in representing dependence structures that arise in situations where extreme component realizations occur together. We demonstrate that it is possible to extend VARTA to work for such dependence structures via the use of the copula theory, which has been used primarily for random vectors in the simulation input-modeling literature, for multivariate time-series input modeling. We show that our copula-based multivariate time-series input model, which includes VARTA as a special case, allows the development of statistically valid fitting and fast sampling algorithms well suited for driving large-scale stochastic simulations.
Cancer Research UK promotes research in surgery
Authors: Johnson Peter
Published: June 2009

In November 2008 Cancer Research UK published its strategy for the next five years (http://science.cancer researchuk.org/research_strategy/) and in doing so made a commitment to enhance the field of research in surgery. This is a recognition of the fact that surgery continues to be the primary modality for the cure and control of cancer but that despite making several important contributions to our knowledge, surgical research has been seen as an area of relative weakness for the UK. This is something that Cancer Research UK is determined to help remedy, in partnership with others such as the National Institute for Health Research, the surgical royal colleges and the specialist associations.
Improving surgery through research: barriers and solutions
Authors: Williams Norman , Edwards Simon
Published: June 2009

The UK government spends over £1.5 billion on medical research every year. Despite substantial year-on-year increases for the last decade, less than 1.5% of this investment is spent on surgical research. Questions are now being asked about the type of medical research undertaken in the UK and its benefit to patient care as well as how innovation and translation can be improved.
The Adherence Support Gap: The ‘Ideal' Versus ‘Reality’ of Antiretroviral Adherence Support Provided by HIV Health Providers in Clinical Practice
Authors: Park-Wyllie Laura Y , Kam Derek , Bayoumi Ahmed M
Published: June 2009

Background

Guidelines suggest that clinicians should provide their patients with antiretroviral adherence support, but there is uncertainty about the types of adherence support clinicians think are important, the methods they use to provide adherence support, and the barriers they face in providing such support in clinical practice.

Objective

To study clinician perspectives on the importance of different antiretroviral adherence support activities and compare these with clinicians' self-reported actual adherence support practices.

Methods

From March to August 2005, surveys were mailed to physicians, pharmacists, and nurses who provide care to HIV patients in Ontario, Canada. The 84-item survey asked providers to rate how necessary it was to provide 30 types of adherence support activities and how frequently they actually provided each of the types of adherence support. From this, we assessed healthcare provider perceptions of best or ideal practices in supporting medication adherence and actual or usual care in adherence support provision. We also examined whether an adherence support gap existed between the provision of best practice adherence support and actual adherence support in clinical practice.

Results

One hundred sixty-nine of 300 mailed surveys were returned, for a response rate of 56%. Respondents were highly specialized in HIV care and nearly all practiced in urban settings. Respondents indicated that most of the surveyed adherence support activities should be provided to all patients. However, most clinicians did not actually provide these adherence supports to their patients to the extent that they desired. We calculated an adherence support gap that ranged from 31% to 75% across the different types of adherence support activities.

Conclusions

We observed important adherence support gaps between ideal best practices in the provision of adherence support and actual provision of adherence support in clinical practice.
Influence of Clinical and Demographic Variables on Mycophenolic Acid Pharmacokinetics in Antineutrophil Cytoplasmic Antibody–Associated Vasculitis
Authors: Joy Melanie S , Hilliard Tandrea , Hu Yichun , Hogan Susan L , Wang Jinzhao , Falk Ronald J , Smith Philip C
Published: June 2009

Background

Mycophenolic acid (MPA) is used off-label to treat many forms of glomerulonephritis.

Objective

To evaluate the pharmacokinetics of MPA and its glucuronide (MPAG) in antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis patients with renal manifestations and to determine the effects of clinical (urinary protein excretion, serum albumin, creatinine clearance) and demographic (age, race, sex) variables on MPA and MPAG pharmacokinetics.

Methods

Twenty-three patients taking MPA at steady-state were evaluated. Plasma and urine samples were collected over 24 hours. Analyses included noncompartmental pharmacokinetics and statistics including Mann-Whitney U test and univariate/multiple regression.

Results

MPA clearance (Cl/F 288 ± 154 mL/min) was approximately 2-fold higher than previously reported from transplant patients and predicted by weight and race (ranked MPA Cl/F = −11.766 + 0.2035 [wt] + 4.9578 [race]: R2 41.8%; p = 0.005). Creatinine clearance (CrCl) less than 60 mL/min resulted in higher MPA exposure, total area under the curve (AUC)0-12, and AUC6-12 as well as unbound AUC0-12. The metabolic ratio (MPAGAUC/MPAAUC) of 8.67 ± 5.57 was lower than that previously reported in renal transplant recipients.

Conclusions

Diminished kidney function (eg, CrCl <60 mL/min) demonstrated enhanced MPA and MPAG exposure in patients with ANCA vasculitis. However, unlike renal transplant recipients, patients with ANCA vasculitis had enhanced Cl/F and diminished metabolic ratio, suggesting the need to comprehensively evaluate the role of disease-specific factors on MPA pharmacokinetics.
Impact of Additional Disabilities on Adaptive Behavior and Support Profiles for People With Intellectual Disabilities
Authors: Harries Julia , Guscia Roma , Nettelbeck Ted , Kirby Neil
Published: June 2009

Numerous researchers have reported a high incidence of additional disabilities coexisting with intellectual disabilities. Although an intuitive link can be made between the existence of multiple disabilities and greater need for support, little has been reported about this relationship. Using measures of adaptive functioning and support needs, we examined the extent to which adaptive and challenging behaviors and consequent support needs (including medical) were impacted by the presence and severity of additional disabilities for individuals with intellectual disabilities. Results show that adaptive behaviors and support needs were meaningfully related to the number and severity of additional disabilities present, whereas this was not so for challenging behaviors. Findings are discussed in terms of contemporary models of disability and functioning.
Monoamine Oxidase A Promoter Gene Associated With Problem Behavior in Adults With Intellectual/Developmental Disabilities
Authors: May Michael E. , Srour Ali , Hedges Lora K. , Lightfoot David A. , Phillips John A. , Blakely Randy D. , Kennedy Craig H.
Published: June 2009

A functional polymorphism in the promoter of the gene encoding monoamine oxidase A has been associated with problem behavior in various populations. We examined the association of MAOA alleles in adult males with intellectual/developmental disabilities with and without established histories of problem behavior. These data were compared with a gender, ethnicity, and age-matched contrast sample. About 43% (15/35) of adults with intellectual/developmental disabilities and problem behavior possessed the low-efficiency version of the MAOA gene. In comparison, 20% (7/35) of adults with intellectual/developmental disabilities and no problem behavior and 20% (7/35) of the contrast group had the short-allele MAOA polymorphism. Therefore, a common variant in the MAOA gene may be associated with problem behavior in adults with intellectual/developmental disabilities.
Comparison of mechanical properties of thermally modified wood at growth ring and cell wall level by means of instrumented indentation tests
Authors: Stanzl-Tschegg Stefanie , Beikircher Wilfried , Loidl Dieter
Published: June 2009

Thermal modification is a well established method to improve the dimensional stability and the durability for outdoor use of wood. Unfortunately, these improvements are usually accompanied with a deterioration of mechanical performance (e.g., reduced strength or higher brittleness). In contrast, our investigations of the hardness properties in the longitudinal direction of beech wood revealed a significant improvement with thermal modification. Furthermore, we applied instrumented indentation tests on different hierarchical levels of wood structure (growth ring and cell wall level) to gain closer insights on the mechanisms of thermal treatment of wood on mechanical properties. This approach provides a variety of mechanical data (e.g., elastic parameters, hardness parameters, and viscoelastic properties) from one single experiment. Investigations on the influence of thermal treatment on the mechanical properties of beech revealed similar trends on the growth ring as well as the on the cell wall level of the wood structure.