bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification and Characterization of a Novel Class of Extracellular Poly(3-Hydroxybutyrate) Depolymerase from Bacillus sp. Strain NRRL B-14911
Authors: Ma Wan-Ting , Lin Ju-Hui , Chen Hui-Ju , Chen Syuan-Yi , Shaw Gwo-Chyuan
Published: September 2011

The catalytic, linker, and denatured poly(3-hydroxybutyrate) (dPHB)-binding domains of bacterial extracellular PHB depolymerases (PhaZs) are classified into several different types. We now report a novel class of extracellular PHB depolymerase from
Bacillus
sp. strain NRRL B-14911. Its catalytic domain belongs to type 1, whereas its putative linker region neither possesses the sequence features of the three known types of linker domains nor exhibits significant amino acid sequence similarity to them. Instead, this putative linker region can be divided into two distinct linker domains of novel types: LD1 and LD2. LD1 shows significant amino acid sequence similarity to certain regions of a large group of PHB depolymerase-unrelated proteins. LD2 and its homologs are present in a small group of PhaZs. The remaining C-terminal portion of this PhaZ can be further divided into two distinct domains: SBD1 and SBD2. Each domain showed strong binding to dPHB, and there is no significant sequence similarity between them. Each domain neither possesses the sequence features of the two known types of dPHB-binding domains nor shows significant amino acid sequence similarity to them. These unique features indicate the presence of two novel and distinct types of dPHB-binding domains. Homologs of these novel domains also are present in the extracellular PhaZ of
Bacillus megaterium
and the putative extracellular PhaZs of
Bacillus pseudofirmus
and
Bacillus
sp. strain SG-1. The
Bacillus
sp. NRRL B-14911 PhaZ appears to be a representative of a novel class of extracellular PHB depolymerases.
Identification and Characterization of Leucocyclicin Q, a Novel Cyclic Bacteriocin Produced by Leuconostoc mesenteroides TK41401
Authors: Masuda Yoshimitsu , Ono Hiroshi , Kitagawa Hiroshi , Ito Haruo , Mu Fuqin , Sawa Naruhiko , Zendo Takeshi , Sonomoto Kenji
Published: September 2011

The culture supernatant of
Leuconostoc mesenteroides
TK41401, isolated from Japanese pickles, possessed antimicrobial activity against broad range of a bacterial genera and particularly strong activity against
Bacillus coagulans
, the major contaminant of pickles. An antimicrobial peptide was purified in three chromatographic steps, and its molecular mass was determined to be 6,115.59 Da by electrospray ionization time-of-flight mass spectrometry (ESI-TOF MS). The primary structure of this peptide was determined by amino acid and DNA sequencing, and these analyses revealed that it was translated as a 63-residue precursor. This precursor showed high similarity to the precursor of lactocyclicin Q, a cyclic bacteriocin produced by
Lactococcus
sp. strain QU 12. The molecular weight calculated after cyclization, which was presumed to involve the same process as in lactocyclicin Q (between L3 and W63), agreed with that estimated by ESI-TOF MS. This peptide was proved to be a novel cyclic bacteriocin, and it was termed leucocyclicin Q. The antimicrobial spectrum of this bacteriocin clearly differed from that of lactocyclicin Q, even though their primary structures were quite similar. This is the first report of a cyclic bacteriocin produced by a strain of the genus
Leuconostoc
.
Cloning-Independent and Counterselectable Markerless Mutagenesis System in Streptococcus mutans
Authors: Xie Zhoujie , Okinaga Toshinori , Qi Fengxia , Zhang Zhijun , Merritt Justin
Published: September 2011

Insertion duplication mutagenesis and allelic replacement mutagenesis are among the most commonly utilized approaches for targeted mutagenesis in bacteria. However, both techniques are limited by a variety of factors that can complicate mutant phenotypic studies. To circumvent these limitations, multiple markerless mutagenesis techniques have been developed that utilize either temperature-sensitive plasmids or counterselectable suicide vectors containing both positive- and negative-selection markers. For many species, these techniques are not especially useful due to difficulties of cloning with
Escherichia coli
and/or a lack of functional negative-selection markers. In this study, we describe the development of a novel approach for the creation of markerless mutations. This system employs a cloning-independent methodology and should be easily adaptable to a wide array of Gram-positive and Gram-negative bacterial species. The entire process of creating both the counterselection cassette and mutation constructs can be completed using overlapping PCR protocols, which allows extremely quick assembly and eliminates the requirement for either temperature-sensitive replicons or suicide vectors. As a proof of principle, we used
Streptococcus mutans
reference strain UA159 to create markerless in-frame deletions of 3 separate bacteriocin genes as well as triple mutants containing all 3 deletions. Using a panel of 5 separate wild-type
S. mutans
strains, we further demonstrated that the procedure is nearly 100% efficient at generating clones with the desired markerless mutation, which is a considerable improvement in yield compared to existing approaches.
Analysis of the LIV System of Campylobacter jejuni Reveals Alternative Roles for LivJ and LivK in Commensalism beyond Branched-Chain Amino Acid Transport
Authors: Ribardo Deborah A. , Hendrixson David R.
Published: September 2011

Campylobacter jejuni
is a leading cause of diarrheal disease in humans and an intestinal commensal in poultry and other agriculturally important animals. These zoonotic infections result in significant amounts of
C. jejuni
present in the food supply to contribute to disease in humans. We previously found that a transposon insertion in
Cjj81176_1038
, encoding a homolog of the
Escherichia coli
LivJ periplasmic binding protein of the leucine, isoleucine, and valine (LIV) branched-chain amino acid transport system, reduced the commensal colonization capacity of
C. jejuni
81-176 in chicks.
Cjj81176_1038
is the first gene of a six-gene locus that encodes homologous components of the
E. coli
LIV system. By analyzing mutants with in-frame deletions of individual genes or pairs of genes, we found that this system constitutes a LIV transport system in
C. jejuni
responsible for a high level of leucine acquisition and, to a lesser extent, isoleucine and valine acquisition. Despite each LIV protein being required for branched-chain amino acid transport, only the LivJ and LivK periplasmic binding proteins were required for wild-type levels of commensal colonization of chicks. All LIV permease and ATPase components were dispensable for
in vivo
growth. These results suggest that the biological functions of LivJ and LivK for colonization are more complex than previously hypothesized and extend beyond a role for binding and acquiring branched-chain amino acids during commensalism. In contrast to other studies indicating a requirement and utilization of other specific amino acids for colonization, acquisition of branched-chain amino acids does not appear to be a determinant for
C. jejuni
during commensalism.
EGFR and KRAS mutations detection on lung cancer liquid-based cytology: a pilot study
Authors: Malapelle Umberto , de Rosa Nicla , Rocco Danilo , Bellevicine Claudio , Crispino Carlo , Illiano Alfonso , Piantedosi Franco Vito , Nappi Oscar , Troncone Giancarlo
Published: September 2011

In advanced non-small-cell lung carcinomas epidermal growth factor receptor (EGFR) and KRAS testing is often performed on cytology. Liquid-based cytology (LBC), which eliminates the need for slide preparation by clinicians, may be very useful. In 42 LBC DNA was extracted twice. One sample was obtained directly from CytoLyt solution, whereas the other DNA sample was derived after smear preparation and laser capture microdissection (LCM) of Papanicolaou-stained cells. EGFR and KRAS mutational analyses were performed by direct sequencing. On CytoLyt-derived DNA four EGFR (9%) and five KRAS (12%) gene mutations were found. When direct sequencing was performed after LCM, the rate of cases that displayed either EGFR or KRAS mutations increased from 21% to 40%. Although time-consuming, LCM makes direct sequencing highly sensitive even on LBC preparations containing only a few cells.
Estimated prevalence of theGYS‐1mutation in healthy Austrian Haflingers
Authors: Schwarz B. , Ertl R. , Zimmer S. , Netzmann Y. , Klein D. , Schwendenwein I. , Hoven R. V. D.
Published: September 2011

The aim of this study was to determine the occurrence and frequency of a mutation in the gene coding for skeletal muscle glycogen synthase type 1 (GYS‐1), which is the cause of equine polysaccharide storage myopathy (PSSM) type 1 in a population of 50 Haflingers.GYS‐1genotyping of 50 Haflingers was performed with a validated restriction fragment length polymorphism (RFLP) assay. The second aim was to compare resting and post‐exercise muscle enzyme activities as well as parameters of glucose metabolism in blood between horses with and without the mutation. Nine of the 50 Haflingers were identified to be heterozygous for the mutation (HR). None was homozygous (HH). The estimated HR prevalence was 18 per cent in this herd. Mean aspartate aminotransferase (AST) activity at rest and mean creatine kinase and AST activity after exercise were significantly higher in HR compared with RR (homozygote normal) horses. No significant differences could be found in the other parameters.
Oxidative stress and heart failure
Authors: Tsutsui Hiroyuki , Kinugawa Shintaro , Matsushima Shouji
Published: September 2011

Oxidative stress, defined as an excess production of reactive oxygen species (ROS) relative to antioxidant defense, has been shown to play an important role in the pathophysiology of cardiac remodeling and heart failure (HF). It induces subtle changes in intracellular pathways, redox signaling, at lower levels, but causes cellular dysfunction and damage at higher levels. ROS are derived from several intracellular sources, including mitochondria, NAD(P)H oxidase, xanthine oxidase, and uncoupled nitric oxide synthase. The production of ROS is increased within the mitochondria from failing hearts, whereas normal antioxidant enzyme activities are preserved. Chronic increases in ROS production in the mitochondria lead to a catastrophic cycle of mitochondrial DNA (mtDNA) damage as well as functional decline, further ROS generation, and cellular injury. ROS directly impair contractile function by modifying proteins central to excitation-contraction coupling. Moreover, ROS activate a broad variety of hypertrophy signaling kinases and transcription factors and mediate apoptosis. They also stimulate cardiac fibroblast proliferation and activate the matrix metalloproteinases, leading to the extracellular matrix remodeling. These cellular events are involved in the development and progression of maladaptive myocardial remodeling and failure. Oxidative stress is also involved in the skeletal muscle dysfunction, which may be associated with exercise intolerance and insulin resistance in HF. Therefore, oxidative stress is involved in the pathophysiology of HF in the heart as well as in the skeletal muscle. A better understanding of these mechanisms may enable the development of novel and effective therapeutic strategies against HF.
Combined Blockade of Integrin-α4β1 Plus Cytokines SDF-1α or IL-1β Potently Inhibits Tumor Inflammation and Growth
Authors: Schmid Michael C. , Avraamides Christie J. , Foubert Philippe , Shaked Yuval , Kang Sang Won , Kerbel Robert S. , Varner Judith A.
Published: September 2011

Tumor-associated macrophages promote tumor growth by stimulating angiogenesis and suppressing antitumor immunity. Thus, therapeutics that inhibit macrophage recruitment to tumors may provide new avenues for cancer therapy. In this study, we showed how chemoattractants stromal cell-derived growth factor 1 alpha (SDF-1α) and interleukin 1 beta (IL-1β) collaborate with myeloid cell integrin-α4β1 to promote tumor inflammation and growth. We found that SDF-1α and IL-1β are highly expressed in the microenvironments of murine lung, pancreatic, and breast tumors; surprisingly, SDF-1α was expressed only by tumor cells, whereas IL-1β was produced only by tumor-derived granulocytes and macrophages. In vivo, both factors directly recruited proangiogenic macrophages to tissues, whereas antagonists of both factors suppressed tumor inflammation, angiogenesis, and growth. Signals induced by IL-1β and SDF-1α promoted the interaction of talin and paxillin with the cytoplasmic tails of integrin-α4β1, thereby stimulating myeloid cell adhesion to endothelium in vitro and in vivo. Inhibition of integrin-α4β1, SDF-1α, or IL-1β was sufficient to block tumor inflammation and growth, and the combined blockade of these molecules greatly accentuated these effects. Furthermore, antagonists of integrin-α4β1 inhibited chemotherapy-induced tumor inflammation and acted synergistically with chemotherapeutic agents to suppress tumor inflammation and growth. These results show that targeting myeloid cell recruitment mechanisms can be an effective approach to suppress tumor progression. Cancer Res; 71(22): 6965–75. ©2011 AACR.
Rapid Detection of Coronary Artery Stenoses With Real-Time Perfusion Echocardiography During Regadenoson Stress
Authors: Porter Thomas R. , Adolphson Mary , High Robin R. , Smith Lynette M. , Olson Joan , Erdkamp Michelle , Xie Feng , O'Leary Edward , Wong Benjamin F. , Eifert-Rain Susan , Hagen Mary E. , Abdelmoneim Sahar S. , Mulvagh Sharon L.
Published: September 2011

Background—

Real-time myocardial contrast echocardiography permits the detection of myocardial perfusion abnormalities during stress echocardiography, which may improve the accuracy of the test in detecting coronary artery stenoses. We hypothesized that this technique could be used after a bolus injection of the selective A2A receptor agonist regadenoson to rapidly and safely detect coronary artery stenoses.

Methods and Results—

In 100 patients referred for quantitative coronary angiography, real-time myocardial contrast echocardiography was performed during a continuous intravenous infusion of 3% Definity at baseline and at 2-minute intervals for up to 6 minutes after a regadenoson bolus injection (400 μg). Myocardial perfusion was assessed by examination of myocardial contrast replenishment after brief high mechanical index impulses. A perfusion defect was defined as a delay (>2 seconds) in myocardial contrast replenishment in 2 contiguous segments. Wall motion was also analyzed. The overall sensitivity/specificity/accuracy for myocardial perfusion analysis in detecting a >50% diameter stenosis was 80%/74%/78%, whereas for wall motion analysis it was 60%/72%/66% (
P
<0.001 for differences in sensitivity). Sensitivity for myocardial perfusion analysis was highest on images obtained during the first 2 minutes after regadenoson bolus (
P
<0.001 compared with wall motion), whereas wall motion sensitivity was highest at the 4-to-6–minute period after the bolus. No significant side effects occurred after regadenoson bolus injection.

Conclusions—

Regadenoson real-time myocardial contrast echocardiography appears to be a feasible, safe, and rapid noninvasive method for the detection of significant coronary artery stenoses.

Clinical Trial Registration—

URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT0087369.
Increased Carotid Intima–Media Thickness is Associated With Higher SYNTAX Score
Authors: Korkmaz Levent , Bektas Huseyin , Korkmaz Ayca Ata , Agaç Mustafa Tarık , Acar Zeydin , Erkan Hakan , Celik Sukru
Published: September 2011

The main purpose of this study was to investigate the relation between carotid intima–media thickness (CIMT) and coronary artery disease (CAD) complexity. Consecutive patients (n = 360) with CAD confirmed by coronary angiography were enrolled. Mean CIMT and the overall SYNTAX score (SXscore) were 0.87 ± 0.12 mm and 15 ± 9, respectively. In univariate analysis, there was a significant correlation between the overall SXscore and CIMT ( r = .42, P < .001), age ( r = .23, P < .001), hypertension ( r = .27, P = 0.001), diabetes ( r = 0.11, P = 0.02), smoking ( r = .24, P = .01), dyslipidemia ( r = .2, P = 0.03), and β-blocker use ( r = .19, P < .001). In multivariate analysis, CIMT (β = .34, P < .001) and age (β = .11, P < .019) were independently associated with SXscore. We have demonstrated a significant relation between CIMT and SXscore. Although this study is correlative and no causative conclusions can be drawn, our findings suggest that increased CIMT could reflect complex coronary artery lesions.
The Acute Effects of Passive Smoking on Mean Platelet Volume in Healthy Volunteers
Authors: Yarlioglues Mikail , Ardic Idris , Dogdu Orhan , Akpek Mahmut , Zencir Cemil , Kasapkara Haci Ahmet , Kelesoglu Saban , Elcik Deniz , Ozdogru Ibrahim , Oguzhan Abdurrahman , Kaya Mehmet Gungor
Published: September 2011

Mean platelet volume (MPV) is an indicator of platelet activation. We investigated the acute effect of passive smoking on MPV in healthy volunteers. Healthy nonsmoker volunteers (n = 90) spent 120 minutes in a smoke-free room. Then they were exposed to passive smoking in 3 groups consisting of 30 volunteers each in group A (carbon monoxide [CO] <7.5 ppm), group B (CO = 7.5-15 ppm), and group C (CO > 15 ppm) for 120 minutes in a smoking room. Mean platelet volume did not change in group A and in the smoke-free room. Mean platelet volume increased significantly at the 60th minute and continued to increase at the 90th and 120th minute in group B. Mean platelet volume increased significantly at the 30th minute and continued to increase at the 60th, 90th, and 120th minute in group C. In conclusion, acute exposure to passive smoking affected MPV according to the duration and intensity of smoke.
High Levels of Serum Uric Acid Impair Development of Coronary Collaterals in Patients With Acute Coronary Syndrome
Authors: Duran Mustafa , Ornek Ender , Murat Sani N. , Turfan Murat , Vatankulu Mehmet A. , Ocak Ayse , Doger Cihan , Yalcin Ahmet A. , Demircelik Muhammed B.
Published: September 2011

We evaluated the association of serum uric acid (SUA) level and development of coronary collateral vessels (CCVs) in patients with acute coronary syndrome (ACS). Patients (n = 224) with ACS were included in the study. Coronary collateral vessels were graded according to the Rentrop scoring system. Rentrop grade 0 was accepted as absence of CCV (group 1; n = 117) and Rentrop grade ≥1 was accepted as presence of CCV (group 2; n = 107). Rentrop 0-1 (poor CCV) were determined in 167 patients and Rentrop 2-3 (good CCV) were determined in 57 patients. Both presence of CCV ( P < .001) and development of good CCV ( P = .003) were significantly associated with low levels of SUA. We suggest that high levels of SUA affect the CCV development negatively in nondiabetic and nonhypertensive patients with ACS.
Supporting Children After Single- Incident Trauma
Authors: Alisic Eva , Boeije Hennie R. , Jongmans Marian J. , Kleber Rolf J.
Published: September 2011

Objective. To strengthen trauma-informed health care by exploring parents’ experiences of assisting their child after single-incident trauma (eg, violence, accidents, and sudden loss). Method. Semistructured interviews with parents (N = 33) of 25 exposed children (8-12 years). Results. Responsive parenting after trauma emerged as a core theme, consisting of ( a) being aware of a child’s needs and ( b) acting on these needs. The authors identified 14 strategies, such as comparing behavior with siblings’ behavior and providing opportunities to talk. Parents felt that their capacity to be responsive was influenced by their own level of distress. Conclusion. The authors propose a model of Relational PTSD (posttraumatic stress disorder) and Recovery to assist health care professionals working with children exposed to trauma. The results also point to the need to recognize the challenge that parents face when supporting a child after traumatic exposure and to align more with parents about procedures that may cause the child to be reminded of the event.
A Review of Sexual Health Web Sites for Adolescents
Authors: Whiteley Laura B. , Mello Justin , Hunt Olivia , Brown Larry K.
Published: September 2011

Background: The popularity of the Internet for health information and the growing availability of online access make the Internet a compelling medium for health promotion and HIV/STI prevention efforts for adolescents. Many private and federally funded programs have incorporated Web-based approaches and online technologies into their sexual education and HIV/STI prevention efforts for adolescents. These efforts have resulted in numerous Web sites and varied online content. This content is currently understudied and underevaluated. In this study, current sexual health Web sites targeted at adolescents were catalogued and coded. Methods Web sites targeted at adolescents were coded for educational content, credibility, usability, as well as interactivity. Results A significant amount of sexual health information geared toward teens is available online. All the Web sites reviewed showed deficiencies in educational content, as well as deficiencies in usability, authority, and interactivity. Planned Parenthood’s Web site was the most well rounded of the sites assessed.
Continuity of care for people with psychotic illness: Its relationship to clinical and social functioning
Authors: Catty Jocelyn , White Sarah , Clement Sarah , Cowan Naomi , Geyer Connie , Harvey Kate , Jones Ian Rees , McLaren Susan , Poole Zoe , Rose Diana , Wykes Til , Burns Tom
Published: September 2011

Background:

The relationship between continuity of care and user characteristics or outcomes has rarely been explored. The ECHO study operationalized and tested a multi-axial definition of continuity of care, producing a seven-factor model used here.

Aims:

To assess the relationship between user characteristics and established components of continuity of care, and the impact of continuity on clinical and social functioning.

Methods:

The sample comprised 180 community mental health team users with psychotic disorders who were interviewed at three annual time-points, to assess their experiences of continuity of care and clinical and social functioning. Scores on seven continuity factors were tested for association with user-level variables.

Results:

Improvement in quality of life was associated with better Experience & Relationship continuity scores (better user-rated continuity and therapeutic relationship) and with lower Meeting Needs continuity factor scores. Higher Meeting Needs scores were associated with a decrease in symptoms.

Conclusion:

Continuity is a dynamic process, influenced significantly by care structures and organizational change.
Mechanistic Modeling of Antigen Sink Effect for Mavrilimumab Following Intravenous Administration in Patients With Rheumatoid Arthritis
Authors: Wang Bing , Lau Yvonne Y. , Liang Meina , Vainshtein Inna , Zusmanovich Mikhail , Lu Hong , Magrini Fabio , Sleeman Matthew , Roskos Lorin
Published: September 2011

Mavrilimumab is a fully human monoclonal antibody that binds to granulocyte‐macrophage colony stimulating factor receptor α (GM‐CSFRα) with high affinity and specificity and has potential application in various inflammatory diseases. The objective of this investigation was to develop a mechanistic population model to characterize the pharmacokinetics of mavrilimumab, the GM‐CSFRα–mediated clearance, and receptor occupancy following single intravenous dosing to patients with rheumatoid arthritis. The internalization rate of mavrilimumab—GM‐CSFRα complex was fixed to a value determined from quantitative confocal fluorescent imaging. The estimated typical first‐order clearance and the central and peripheral distribution volumes were 3.79 mL/kg/d, 39.6 mL/kg, and 50.3 mL/kg, respectively. The systemic GM‐CSFRα expression level was estimated to be 0.0782 nM, and the equilibrium dissociation constant (0.103 nM) was in good agreement with the monovalent affinity determined by surface plasmon resonance. By fitting to the observed pharmacokinetic data, the mechanistic model predicted that systemically greater than 90% GM‐CSFRα blockade by mavrilimumab was achieved and maintained up to 4, 7, and 11 weeks following single 1‐, 3‐, and 10‐mg/kg administrations, respectively. Posterior visual predictive check and bootstrapping suggest that the mechanistic model is reasonably robust and can be used to predict mavrilimumab exposure under various scenarios for future clinical trial design.
A combined dimensional analysis and optimization approach for determining elastic–plastic properties from indentation tests
Authors: Kang J J , Becker A A , Sun W
Published: September 2011

Loading–unloading curves obtained from indentation experiments can be used to extract elastic-plastic mechanical properties using the finite element (FE) method. However, extensive computation times are required in such an approach due to the fact that the optimization procedure is based on iterative FE computations. In this study, a combined dimensional analysis and optimization approach is developed for the determination of the elastic-plastic mechanical properties of power law materials, without the need for iterative FE analysis. A parametric study using FE analysis is first conducted to construct the appropriate dimensional functions. The optimization algorithm with either a single indenter or dual indenters is then used to obtain the material properties from the given loading–unloading curves. Different sets of materials properties are used and the accuracy and validity of the predicted mechanical properties using the single indenter or dual indenters are assessed.
Olfactory hallucinations in primary headache disorders: Case series and literature review
Authors: Coleman Elisheva R , Grosberg Brian M , Robbins Matthew S
Published: September 2011

Background: Olfactory hallucinations (phantosmias) have rarely been reported in migraine patients. Unlike visual, sensory, language, brainstem, and motor symptoms, they are not recognized as a form of aura by the International Classification of Headache Disorders.

Methods: We examined the clinical features of 39 patients (14 new cases and 25 from the literature) with olfactory hallucinations in conjunction with their primary headache disorders.

Results: In a 30-month period, the prevalence of phantosmias among all patients seen at our headache center was 0.66%. Phantosmias occurred most commonly in women with migraine, although they were also seen in several patients with other primary headache diagnoses. The typical hallucination lasted 5–60 minutes, occurred shortly before or simultaneous with the onset of head pain, and was of a highly specific and unpleasant odor, most commonly a burning smell. In the majority of patients, phantosmias diminished or disappeared with initiation of prophylactic therapy for headaches.

Conclusions: We propose that olfactory hallucinations are probably an uncommon but distinctive form of migraine aura, based on their semiology, timing and response to headache prophylaxis.
Quantifying the Burden of Writing Research Articles in a Second Language
Authors: Hanauer David I. , Englander Karen
Published: September 2011

This article provides quantitative data to establish the relative, perceived burden of writing research articles in English as a second language. Previous qualitative research has shown that scientists writing English in a second language face difficulties but has not established parameters for the degree of this difficulty. A total of 141 Mexican, Spanish-speaking scientists from a range of scientific disciplines participated in a survey which directly compared writing scientific research articles in Spanish and English as a second language. The survey questions defined burden in relation to perceived difficulty, dissatisfaction, and anxiety. The results revealed that the experience of writing a scientific research article in English as a second language is significantly different than the experience writing in a first language and that this writing process was perceived as 24% more difficult and generated 11% more dissatisfaction and 21% more anxiety. The findings suggest that the use of English as a second language is the cause of this increased burden.
Effect of fenugreek seeds extract on cyclophosphamide-induced histomorphometrical, ultrastructural and biochemical changes in testes of albino mice
Authors: Sakr Saber A , Mahran Hoda A , Abo-El-Yazid Samah M
Published: September 2011

Cyclophosphamide (CPA) is an anticancer drug used in the treatment of a variety of neoplastic lesions. On the other hand, treatment with CPA was accompanied by different toxic effects on different body organs. The present work was conducted to study the effect of fenugreek seed extract on histomorphometrical and ultrastructural changes induced by CPA in testes of albino mice. Twenty animals were given CPA (7.0 mg/kg body weight) three times/week orally for 8 weeks and were killed after 4 and 8 weeks. Testis of CPA-treated mice showed many histological alterations including appearance of irregular seminiferous tubules, reduction in the number of all spermatogenic cells, degeneration of Leydig cells and appearance of intertubular hemorrhage. Concerning the ultrastructural changes, abnormalities in spermatogonia (A and B), spermatocytes, round and elongated spermatids were observed. Degenerated Sertoli cells and degenerated interstitial tissue with abnormal Leydig cells were also seen. Moreover, administration of CPA to animals significantly increased malondialdehyde (MDA, lipid peroxidation marker) and decreased superoxide dismutase (SOD) and catalase (CAT). These changes were time-dependent. Treating animals with CPA and fenugreek seed extract (0.4 g/kg body weight) led to an improvement in the histological and ultrastructural pictures of the testis together with reduction in the level of serum MDA and increase in the activities of serum SOD and CAT. In conclusion, the results of the present work indicated that fenugreek had ameliorative effect against testis damage induced by CPA and this may be mediated by its potent antioxidant activities.
The Role of Power in Nonprofit Innovation
Authors: Dover Graham , Lawrence Thomas B.
Published: September 2011

Innovation is a critical issue for nonprofit organizations and the ability to innovate over time represents an important, unresolved challenge. In this article, we examine continuous innovation in nonprofits from a political perspective. We explore the role of power in shaping how and whether nonprofits are able to continuously innovate. More specifically, we examine how different forms of power are tied to different stages in the innovation process and the implications when those forms of power are under- or overdeveloped. We argue that certain characteristics of nonprofits can complicate the power dynamics associated with each stage of the innovation process. We propose that power imbalances in nonprofits can lead to four innovation pathologies: “nothing happens,” “nothing changes,” “nothing scales,” or “nothing adapts.” This article provides a framework to guide future research into nonprofit innovation as well as a practical tool for individuals and organizations who seek to facilitate continuous innovation.
Optimization of process parameters in wire electrical discharge machining of TiB2 nanocomposite ceramic
Authors: Amini H , Soleymani Yazdi M R , Dehghan G H
Published: September 2011

Wire electrical discharge machining (WEDM) is a widely accepted non-traditional material removal process used to manufacture components with intricate shapes and profiles. The selection of optimum machining conditions for obtaining higher machining efficiency and increasing the accuracy of products are the most important task when the WEDM process is used for machining new advanced material such as nanocomposite ceramics.

In this paper, a series of experiments has been carried out over a wide range of machining conditions. An L32 orthogonal array based on the Taguchi method for design of experiments is used to conduct the experiments. Then, by using a multilayer perceptron neural network, process modelling is performed and the most effective parameters on the process variables (i.e. material removal rate and surface roughness) are determined. Results demonstrate a very good modelling capacity of the proposed neural model. Finally, a genetic algorithm is used to optimize the process performance of WEDM. Additional experiments are performed to verify the adequacy of the optimization method. The optimization results are shown to be in good agreement with the experimental process outputs.
Actuation schemes of a spatial 3-PPRR parallel mechanism
Authors: Zhao J-S , Chu F , Feng Z-J , Dai J S
Published: September 2011

This paper presents a systematic method to analyse actuation schemes. With the wide application of complex spatial mechanisms in engineering the number of excess constraints included in a mechanism is increasing. As a result, there are an increasing number of cases in which the number of actuators needed to control an end-effector is larger than the number of degrees of freedom possessed by the end-effector. The mechanism architecture is first presented and then the mobility of the mechanism is analysed in terms of independent parameters in position constraint equations. Finally, the possible and feasible actuation schemes for the end-effector are generated and analysed.
Mechanics of advanced materials for lightweight structures
Authors: Altenbach H
Published: September 2011

In recent years, there have been a lot of new developments concerning the use of advanced materials for lightweight structures. Examples are long- and short-fibre-reinforced composites, sandwiches, foams, and, last but not least, nanostructures. The analysis of structures made of these materials can be performed on the basis of the Mechanics of Composites. However, stimulated by new applications, new manufacturing technologies, new material compositions, etc. a review of the Mechanics of Composites is necessary.

In this article, some of the actual trends are discussed, for example developments in the application of long- and short-fibre-reinforced composites, laminates affected by multifield loadings, effective property-based analysis of foams, and the description of nanostructures within the concepts of Continuum Mechanics. The starting point of the review are the Engineering Mechanics basics on the level of the BSc program, that means the classical Strength of Materials. Extensions of Materials Strength foundations (for example, inclusion of anisotropy) are often sufficient as first improved estimates. If it is necessary, elements of Continuum Mechanics, of Material Testing or Numerical Solution Techniques can be implied.

The every year increasing number of publications in the field of advanced materials for lightweight structures does not allow to give a complete overview over the state of the art. Recognizing this fact, the author will give a report only of directions related to his own research group and/or in the surrounding of his team.
Two-dimensional simulation of thermal loading with horizontal heat sources
Authors: Jamalabadi M Y A , Ghassemi M , Hamedi M H
Published: September 2011

A numerical investigation has been made of thermal radiation effects in an enclosure, which is formed by a constant temperature wall, an adiabatic wall, two openings, and block heat sources. The relevant governing parameters were the heating number, Nr from 0.05 to 500, the cavity aspect ratio, A =  H/ L from 0.1 to 1, and the number of heaters, N, an odd number ranging from 1 to 19. Heat transfer by natural convection solely and with thermal radiation on the thermal and flow characteristics of the system is studied. A parametric study illustrates the influence of the heating number, aspect ratio, the number of heaters, thermal radiation on the thermal loading characteristics of the system, Nusselt number, and the maximum stream function rate. The results reveal the main characteristics of thermal loading by radiative heat sources.
Multi-criteria decision-making method-based approach to determine a proper level for extrapolation of Rainflow matrix
Authors: Wang J , Hu J , Wang N , Yao M , Wang Z
Published: September 2011

To obtain the genuine load spectra of the components of engineering vehicles, the influencing factors in the extrapolation of load spectra should be considered because these are of paramount importance. In the present paper, a multi-criteria decision-making method (MCDM) is proposed to determine the proper upcrossing of the high and low levels (UHLL) for extrapolation of the Rainflow matrix (RFM). First, the distribution characteristics of load amplitude extracted from observed RFMs are obtained. Subsequently, five criteria, namely, the statistic of mean, statistic of variance, coefficient of skewness, coefficient of kurtosis, and the experts’ preference, are selected to describe the fitting accuracy of the Weibull probability density function. Finally, the relationship between the load threshold and the level crossing function is determined after calculating their relative importance, and consequently, the proper UHLL is obtained. The usefulness and validity of the proposed method is illustrated by two typical load-time histories. Results show that the MCDM-based method can combine the subjective and objective factors and obtain an optimal load level.
A control method to suppress the swing vibration of a hybrid excavator using sliding mode approach
Authors: Jin K , Park T , Lee H
Published: September 2011

This article presents a control method for suppressing the swing vibration of a hybrid excavator. For control design, dynamic models of typical swing motions of the hybrid excavator are derived using a system identification technique. Because the system states of theobtained models are not directly measurable, a sliding mode observer is designed to estimate the system states. A sliding mode control is designed to provide robust tracking performance against the parameter variations and uncertain non-linearities caused by changes in the working conditions. A complicated mathematical model of the hybrid excavator which captures detailed mechanical, electrical, and hydraulic characteristics is developed for system analysis and simulation. The feasibility and effectiveness of the proposed control method are verified by simulations and actual tests in comparison with a conventional proportional and integral controller.
A linear time-varying approach for robustness analyses of a re-entry flight technology demonstrator
Authors: Tancredi U , Grassi M , Corraro F , Vitale A , Filippone E
Published: September 2011

A novel robustness analysis technique is proposed for atmospheric re-entry applications. The problem is stated as a finite time stability (FTS) analysis of linear time-varying (LTV) systems on a compact time domain, subject to bounded variations in initial state and unknown parameters. The FTS property is formulated as the inclusion of all the possible system trajectories into a pre-specified time-varying subset of the state space. Based on assuming the involved sets are polytopes, the proposed approach allows deducing the system FTS from the property verification on a limited number of numerically computed system trajectories. An additional result is presented which allows determination of a conservative estimate of the maximum norm-bound of time-varying perturbations under which the LTV system remains finite time stable. Results of the application of the proposed technique to a re-entry technology demonstrator are presented which demonstrate its effectiveness in complementing conventional linear time invariant-based analyses. Results also show that it is computationally viable and allows linking the system robustness to a quantitative analysis of the system trajectory dispersion around the nominal one due to concurrent initial state dispersion and uncertain parameters effects, which aids in evaluating mission objectives fulfilment.
Study of an upper arm exoskeleton for gravity balancing and minimization of transmitted forces
Authors: Dubey V N , Agrawal S K
Published: September 2011

An upper-arm wearable exoskeleton has been designed for the assistance and functional training of humans. One of the goals of this design is to provide passive assistance to a user by gravity balancing, while keeping the transmitted forces to the shoulder joints at a minimum. Consistent with this goal, this paper discusses: analytical gravity balancing design conditions for the structure of the exoskeleton; a possible implementation of these conditions into practical designs; the minimization of transmitted joint forces to the shoulder while satisfying the gravity balancing conditions; the numerical optimization of the system for gravity balancing and minimization of transmitted forces; and the effect of parameter variation on joint moments and joint forces via numerical optimization.

An implementation of the design was undertaken using zero-free-length springs. The design idea presented in this paper may be useful in relieving the actuators effort of exoskeletons to support the weight of the arm and therefore the possibility of using small actuators and making the system light and portable or even a stand-alone passive support device can be developed based on these gravity balancing conditions.
Modelling of green electricity effects on oligopoly market
Authors: Meszaros M T , Shrestha S O Bade
Published: September 2011

This article builds a simulation model to analyse the effect of a change in the main policy variables of the British Renewable Obligation System, i.e. how the increase in the minimum requirement of green electricity can affect the prices and quantities in the electricity market under oligopoly market structure. The results show that the increasing quota obligation increases the price of electricity. The outcomes of this computational model emphasize the importance of the capacity limit which can constrain the market power and increase the competition in the market. In addition, the simulation shows that the integration of fossil-fuel and renewable producers has very small effect on production and prices because of the capacity limits.
Improved method to mitigate the effect of coal fuel switching on critical process parameters of a steam generator in a thermal power plant
Authors: Dharmalingam S , Sivakumar L , Anandhi T , Umapathy M
Published: September 2011

The design and performance of steam generators supplied to thermal power plants are greatly influenced by the properties of coal burnt. All coals are not same and the variation of heating value of coal supplied to boiler results in changes in critical process parameters like pressure and temperature of main steam produced. These fluctuations are normally controlled by master pressure controller, provided the variation in heating value is within certain limits. If the heating value of coal being burnt varies substantially, a remedial measure is necessary to control the pressure and temperature fluctuations during coal fuel switching. The composition of the coal burnt currently in a boiler is determined from an online analyser, and an embedded controller computes the current heating value of the coal and suitably modifies the gains of all the controllers to arrest the undue fluctuations in pressure and temperature. A validated mathematical model for a typical 500 MW plant is used to simulate the variations in pressure and temperature of steam with normal and embedded controllers. Significant reduction in pressure and temperature variation has been achieved with an embedded controller. This article discusses the improved method of ensuring optimum boiler performance during coal fuel switchover.
An element-oriented model simplification algorithm based on dynamic similarity
Authors: Hung Y H , Wu C H , Hong C W
Published: September 2011

This paper presents an element-oriented model simplification algorithm (EO-MSA) in multi-physical domains. It aims to generate a simplified model to release computational loading while maintaining model fidelity. The dynamics of the multi-physical system can be constructed based on a unified bond graph approach. This EO-MSA approach eliminates those bond graph elements which influence the system behaviour insignificantly in the mathematical model. This study proposes two newly-defined indices, dynamic similarity ( DS), and model similarity index ( MSI), to evaluate the similarity of candidates which are order reduced. Ten error-dynamics modules are mathematically constructed and structurally classified for both the DS and the MSI. The reduced model with minimum MSI can be determined using this approach. Quarter-car simulation results demonstrate that this EO-MSA approach is capable of reducing system complexity while maintaining fidelity with satisfactory tolerance.
Recommendations for using XRF core scanning as a tool in tephrochronology
Authors: Kylander Malin E. , Lind Ewa M. , Wastegård Stefan , Löwemark Ludvig
Published: September 2011

X-ray fluorescence (XRF) core scanning is a relatively new arrangement of a classic analytical technique which allows for non-destructive, in situ XRF analysis of sediment cores from submillimetre resolution upwards. In this contribution we explore the use of XRF core scanning for tephrochronology based on the analysis of three gyttja-rich sediment cores from the Faroe Islands. Using a combination of optical and radiographic images, analytical parameters and elemental profiles (Si, K, Ca, Ti, Mn, Fe, Sr and Zr), higher concentration basaltic tephra layers (>1000 shards/cm3) were positively identified. The XRF core scanning did not capture the lower concentration (<850 shards/cm3) rhyolitic layers found in the core. The elemental data generated for the detected tephra layers using XRF core scanning was not comparable to individual shard analysis by electron microprobe. We recommend using XRF core scanning for tephra screening in order to localize depths for high-resolution subsampling and to avoid depths where sediment mixing has caused tailing/mixing of the tephra signal. At the studied site the basaltic Saksunarvatn ash as well as a tephra belonging to the Askja-S/10 ka eruption were identified.
Generic Versus Branded Enoxaparin in the Prevention of Venous Thromboembolism Following Major Abdominal Surgery
Authors: Gomes Marise , Ramacciotti Eduardo , Henriques Alexandre Cruz , Araujo Gilson Roberto , Szultan Luiz Arnaldo , Miranda Fausto , Thethi Indermohan
Published: September 2011

Introduction: Several generic low-molecular-weight heparins (LMWHs) have recently become available worldwide, including the United States. Companies have filed for regulatory approval of generic versions in many countries, based only on compound biochemical characteristics or its immunogenicity. Methods: Prospective study to evaluate the comparative effect of 2 enoxaparins (Sanofi-Aventis branded enoxaparin [SAe] vs eurofarma-enoxaparin [Ee], a generic version) as prophylaxis for venous thromboembolism (VTE) following major abdominal surgery. A total of 200 patients were randomized in a 1:1 ratio either to receive 40 mg of SAe or Ee subcutaneously (sc) once daily (od) postoperatively for 7 to 10 days. Compressive ultrasound was performed on day 10 + 4. Results: No statistically significant differences between the 2 groups were detected. In all, 2 SAe patients presented deep vein thrombosis ([DVT] 2.1%), none of the Ee group. No major bleeding events occurred. Conclusions: This exploratory trial suggests that the generic LMWH is probably as safe and as effective as the branded enoxaparin (Lovenox, Brazil) in the prophylaxis of VTE in this population.