bluuebunny/crossref_metadata_2025 huggingface dataset:
Levodopa infusion does not decrease the onset of abnormal involuntary movements in parkinsonian rats
Authors: Papathanou Maria , van der Laan Rika , Jenner Peter , Rose Sarah , McCreary Andrew C.
Published: November 2012

The short duration of effect of levodopa is linked to pulsatile stimulation of striatal dopamine receptors and dyskinesia induction. However, the recent introduction of intraduodenal (i.d.) infusions and novel oral controlled release formulations of l‐dopa may prevent dyskinesia induction and reduce the severity of established involuntary movements. We have compared the effects of twice‐daily intraperitoneal (i.p.) administration and daily i.d. infusion of l‐dopa on the induction and expression of abnormal involuntary movements in 6‐hydroxydopamine (6‐OHDA)‐lesioned rats. Animals were treated with either twice‐daily i.p. administration of l‐dopa/carbidopa (7.85/12.5 mg/kg) or an 8‐hour i.d. infusion of l‐dopa/carbidopa (20/5 mg/mL; infusion rate: 0.04 mL/h) for 14 days, after which treatments were switched between groups and continued for a further 14 days. Pulsatile i.p. administration of l‐dopa induced moderate to severe abnormal involuntary movements, which gradually increased in severity over the 14 days, but i.d. infusion of l‐dopa induced abnormal involuntary movements of a similar severity. Switching from continuous i.d. to pulsatile i.p. administration of l‐dopa continued to provoke severe abnormal involuntary movements expression. Switching from pulsatile i.p. to continuous i.d. l‐dopa administration did not alter the peak abnormal involuntary movement severity but tended to reduce their duration. Treatment with less pulsatile l‐dopa administration using i.d. infusion does not reduce the risk of the appearance of dyskinesia. By contrast, the duration of established dyskinesia can be reduced by more continuous l‐dopa delivery in agreement with clinical experience. © 2012 Movement Disorder Society
A novel β‐nucleating agent for isotactic polypropylene
Authors: Ma Yu‐jie , Xin Mingliang , Xu Kai , Chen Mingcai
Published: November 2012

The nucleating ability of p‐cyclohexylamide carboxybenzene (β‐NA) towards isotactic polypropylene (iPP) was investigated by differential scanning calorimetry, X‐ray diffraction, polarized optical microscopy and scanning electron microscopy. β‐NA is identified to have dual nucleating ability for α‐iPP and β‐iPP under appropriate kinetic conditions. The formation of β‐iPP is dependent on the content of β‐NA. The content of β‐phase can reach as high as 96.96% with the addition of only 0.05 wt% β‐NA. Under non‐isothermal crystallization the content of β‐iPP increases with increasing cooling rate. The maximum β‐crystal content is obtained at a cooling rate of 40 °C min–1. The supermolecular structure of the β‐iPP is identified as a leaf‐like transcrystalline structure with an ordered lamellae arrangement perpendicular to the special surface of β‐NA. Under isothermal crystallization β‐crystals can be formed in the temperature range 80–140 °C. The content of β‐crystals reaches its maximum value at a crystallization temperature of 130 °C. © 2012 Society of Chemical Industry
Integration of phosphoproteomic, chemical, and biological strategies for the functional analysis of targeted protein phosphorylation
Authors: Guo Mingquan , Huang Bill X.
Published: November 2012

Reversible phosphorylation, tightly controlled by protein kinases and phosphatases, plays a central role in mediating biological processes, such as protein–protein interactions, subcellular translocation, and activation of cellular enzymes. MS‐based phosphoproteomics has now allowed the detection and quantification of tens of thousands of phosphorylation sites from a typical biological sample in a single experiment, which has posed new challenges in functional analysis of each and every phosphorylation site on specific signaling phosphoproteins of interest. In this article, we review recent advances in the functional analysis of targeted phosphorylation carried out by various chemical and biological approaches in combination with the MS‐based phosphoproteomics. This review focuses on three types of strategies, including forward functional analysis, defined for the result‐driven phosphoproteomics efforts in determining the substrates of a specific protein kinase; reverse functional analysis, defined for tracking the kinase(s) for specific phosphosite(s) derived from the discovery‐driven phosphoproteomics efforts; and MS‐based analysis on the structure–function relationship of phosphoproteins. It is expected that this review will provide a state‐of‐the‐art overview of functional analysis of site‐specific phosphorylation and explore new perspectives and outline future challenges.
Tissue proteomics in pancreatic cancer study: Discovery, emerging technologies, and challenges
Authors: Pan Sheng , Brentnall Teresa A. , Kelly Kimberly , Chen Ru
Published: November 2012

Pancreatic cancer is a highly lethal disease that is difficult to diagnose and treat. The advances in proteomics technology, especially quantitative proteomics, have stimulated a great interest in applying this technology for pancreatic cancer study. A variety of tissue proteomics approaches have been applied to investigate pancreatic cancer and the associated diseases. These studies were carried out with various goals, aiming to better understand the molecular mechanisms underlying pancreatic tumorigenesis, to improve therapeutic treatment and to identify cancer associated protein signatures, signaling events as well as interactions between cancer cells and tumor microenvironment. Here, we provide an overview on the tissue proteomics studies of pancreatic cancer reported in the past few years in light of discovery and technology development.
Proteomics for understanding miRNA biology
Authors: Huang Tai‐Chung , Pinto Sneha M. , Pandey Akhilesh
Published: November 2012

MicroRNAs (miRNAs) are small noncoding RNAs that play important roles in posttranscriptional regulation of gene expression. Mature miRNAs associate with the RNA interference silencing complex to repress mRNA translation and/or degrade mRNA transcripts. Mass spectrometry‐based proteomics has enabled identification of several core components of the canonical miRNA processing pathway and their posttranslational modifications which are pivotal in miRNA regulatory mechanisms. The use of quantitative proteomic strategies has also emerged as a key technique for experimental identification of miRNA targets by allowing direct determination of proteins whose levels are altered because of translational suppression. This review focuses on the role of proteomics and labeling strategies to understand miRNA biology.
Membrane proteomics by high performance liquid chromatography–tandem mass spectrometry: Analytical approaches and challenges
Authors: Vuckovic Dajana , Dagley Laura F. , Purcell Anthony W. , Emili Andrew
Published: November 2012

Membrane proteins (MPs) play diverse biologically important structural and functional roles including molecular transport, cell communication, and signal transduction. The dysfunctions of many are linked to deleterious human diseases and thus are of utmost importance in drug discovery. MPs comprise approximately 20–30% of all open reading frames (ORFs), however they are typically under‐represented in many LC‐MS proteomics experiments due to their low abundance and poor solubility. To address these analytical challenges, various MP enrichment, solubilization, digestion, and fractionation strategies have been employed to further improve the coverage of the membrane systems while maintaining compatibility with MS detection. This review discusses both established and emerging high‐throughput gel‐free analytical workflows in membrane proteomics, and the inherent advantages, disadvantages, and orthogonality of the various approaches. The issues of critical importance for successful LC‐MS/MS detection such as detergent selection and minimizing ion suppression in detergent‐based workflows are discussed in detail. Recent studies comparing the performance of different analytical strategies are highlighted in order to provide practical insight into the choice of the most appropriate method for membrane‐centric applications ranging from cell surface biomarker discovery to MP interaction network mapping.
Ivabradine (Procoralan): new treatment for chronic heart failure
Authors: Chaplin Steve , Davis Russell
Published: November 2012

Ivabradine (Procoralan) is a new treatment for heart failure in patients in sinus rhythm with a heart rate ≥75bpm. In our New products review, Steve Chaplin presents the clinical data relating to its efficacy and adverse events and Dr Russell Davis discusses its place in treatment.
The roles of thermalized and hot carrier diffusion in determining light yield and proportionality of scintillators
Authors: Grim J. Q. , Li Q. , Ucer K. B. , Burger A. , Bizarri G. A. , Moses W. W. , Williams R. T.
Published: November 2012

Numerical modeling and comparison to experiment in the materials for which suitable parameters have been measured confirm that three of the most important material parameters for predicting proportionality and the related host‐dependent light yield (LY) of scintillators are (i) the carrier diffusion coefficients (including hole self‐trapping if present, and hot‐electron diffusion if unthermalized), (ii) the kinetic order and associated rate constant of nonlinear quenching, and (iii) deep‐trapping probability. Thermalized carrier diffusion appears sufficient to describe the main trends in oxides and semiconductors. For heavier halide hosts, it appears necessary to take account of hot‐electron diffusion to explain several important host‐dependent trends.
Oligo‐viologen/SWCNT nano‐composites: Preparation and characterization
Authors: Constantin Veronica‐Alina , Cao Liangcheng , Sadaf Shamaila , Walder Lorenz
Published: November 2012

The synthesis and characterization of two types of viologen polymer modification of semiconducting carbon nanotubes (poly‐I‐CNT and poly‐II‐CNT) are described. The monomer I is a large three‐arm star‐shaped compound consisting of three benzyl and three phenyl viologen subunits. Electrochemical polymerization via benzylic radical formation was used. The star arms in poly‐I‐CNT are well‐resolved structures in two‐dimensional crystallized fashion (from STM), pointing to self‐assembling prior to polymerization. Besides being completely surface covered, individual SWCNTs are interconnected with the polymer in the poly‐I‐CNT composite material. Poly‐II‐CNT was prepared by chemical reduction of N′‐methyl‐N‐aminophenyl viologens. Repetitive viologen oligomer brushes are observed along the SWCNT after polymerization. The functionalization is confirmed by XPS, electrochemistry, and Raman spectroscopy.

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Growth of carbon nanotubes on carbon fibers without strength degradation
Authors: De Greef Niels , Magrez Arnaud , Couteau Edina , Locquet Jean‐Pierre , Forró Lászlo , Seo Jin Won
Published: November 2012

Carbon nanotubes (CNTs) are grown on PAN‐based carbon fibers by means of catalytic chemical vapor deposition technique. By using catalytic thermal decomposition of hydrocarbon, CNTs can be grown in the temperature range of 650–750 °C. However, carbon fibers suffer significant damages resulting in decrease of initial tensile strength. By applying the oxidative dehydrogenation reaction of C2H2 with CO2, we found an alternative way to grow CNTs on carbon fibers at low temperatures, such as 500 °C. Scanning electron microscope results combined with single fiber tests indicate that this low temperature growth enables homogeneous grafting of CNTs onto carbon fibers without degradation of tensile strength.
Synthesis and Surface Activity of Bisphosphate Gemini Surfactants
Authors: Gotmukle Sharad B. , Bhagwat Sunil S.
Published: November 2012

Anionic bisphosphodiester gemini surfactants with two different spacer moieties and varying alkyl chain lengths were synthesized and investigated for their surface active properties. The equilibrium and dynamic surface tension studies were carried out using the Wilhelmy plate technique and maximum bubble pressure method respectively. It was found that these gemini surfactants possess lower critical micellar concentration values, and reduce the surface tension to a greater extent in comparison with the conventional analogues. The efficiency of the synthesized gemini surfactants was also evaluated. The results of surface activities obtained were correlated with the structures of gemini surfactants. The dynamic surface tension measurements showed that the geminis with long chains adsorb very slowly at the air/water interface within the time span of measurements. These gemini surfactants showed low foamability.
HuR posttranscriptionally regulates early growth response‐1 (Egr‐1) expression at the early stage of T cell activation
Authors: Mou Zongchun , You Jia , Xiao Qianghai , Wei Youheng , Yuan Juan , Liu Yong , Brewer Gary , Ma Wei-Jun
Published: November 2012

T cell activation depends on appropriate and precise regulation of gene expression. Here we find that rapidly translocated RNA‐binding protein HuR, forms messenger ribonucleoprotein (mRNP) complexes with transiently expressed mRNAs encoding early‐response transcription factors, including c‐Fos, c‐Jun, and Egr‐1. Knockdown and overexpression assays demonstrated that proper posttranscriptional control of Egr‐1 expression requires HuR‐mediated translation control. Further analysis showed that the Egr‐1 3′UTR, which contains AU‐rich elements (AREs) and interacts directly with HuR, suppresses reporter gene expression and mediates posttranscriptional regulation of Egr‐1 by HuR. These findings underscore an essential role for HuR in regulating early events during T cell activation.
Predictors of progression to severe Alzheimer's disease in an incidence sample
Authors: Rabins Peter V. , Schwartz Sarah , Black Betty S. , Corcoran Christopher , Fauth Elizabeth , Mielke Michele , Christensen Jessica , Lyketsos Constantine , Tschanz JoAnn
Published: November 2012

Background

Little is known about factors influencing time to severe Alzheimer's disease (AD).

Methods

Incident cases of AD in the Cache County Memory Study were identified. Severe AD was defined as Mini‐Mental State Examination score of ≤10 or Clinical Dementia Rating Scale score of 3; cases with either Mini‐Mental State Examination score of ≥16 or Clinical Dementia Rating <2 were not categorized as severe AD. Kaplan–Meier, log‐rank tests, and Cox analyses were used to identify demographic, clinical, and genetic correlates of time to progression to severe AD.

Results

Sixty‐eight of 335 cases of incident AD developed severe dementia. In bivariate analyses, female gender, less than high school education, at least one clinically significant Neuropsychiatric Inventory domain at baseline, and the youngest and oldest ages exhibited shorter time to severe AD. In competing risk analysis, subjects with mild or at least one clinically significant Neuropsychiatric Inventory domain score, and subjects with worse health were more likely to progress to severe dementia or death.

Conclusions

Demographic and clinical variables predict progression to severe AD. Further study should examine whether these relationships are causal or correlational.
Cognitive and functional resilience despite molecular evidence of Alzheimer's disease pathology
Authors: Negash Selam , Xie Sharon , Davatzikos Christos , Clark Christopher M. , Trojanowski John Q. , Shaw Leslie M. , Wolk David A. , Arnold Steven E.
Published: November 2012

Background

The correlation between neuropathological lesions and cognition is modest. Some individuals remain cognitively intact despite the presence of significant Alzheimer's disease (AD) pathology, whereas others manifest cognitive symptoms and dementia in the same context. The aim of the present study was to examine cognitive and cerebral reserve factors associated with resilient functioning in the setting of AD pathology.

Methods

University of Pennsylvania Alzheimer's Disease Center research participants with biochemical biomarker evidence of AD pathology (cerebrospinal fluid amyloid‐β1‐42 <192 pg/mL) and comparable medial temporal lobe atrophy were categorized by Clinical Dementia Rating Scale‐Sum of Boxes (CDR‐SOB) score as AD dementia (CDR‐SOB >1) or AD resilient (CDR‐SOB ≤0.5). Groups were compared for a variety of demographic, clinical, and neuroimaging variables to identify factors that are associated with resilience to AD pathology.

Results

A univariate model identified education and intracranial volume (ICV) as significant covariates. In a multivariate model with backward selection procedure, ICV was retained as a factor most significantly associated with resilience. The interaction term between ICV and education was not significant, suggesting that larger cranial vault size is associated with resilience even in the absence of more education.

Conclusions

Premorbid brain volume, as measured through ICV, provided protection against clinical manifestations of dementia despite evidence of significant accumulations of AD pathology. This finding provides support for the brain reserve hypothesis of resilience to AD.
Predictors and outcomes for caregivers of people with mild cognitive impairment: A systematic literature review
Authors: Seeher Katrin , Low Lee‐Fay , Reppermund Simone , Brodaty Henry
Published: November 2012

Background

Dementia caregiving is strongly linked to depression, anxiety, and burden in caregivers. Little is known about whether the same holds for people supporting an older person with mild cognitive impairment (MCI). We aim to systematically review the current evidence for negative caregiver outcomes in MCI using Pearlin and colleagues' stress process model as a theoretical framework.

Methods

Widely used scientific literature databases were searched using MCI‐ and caregiver‐related terms with “AND” relations. Results were limited to quantitative English language articles published in peer‐reviewed journals between 1980 and November 2010.

Results

Of the 266 identified articles, six reported relevant depression data on 988 MCI caregivers (73% spouses). The pooled Center for Epidemiologic Studies Depression scale (CES‐D) mean score was 12.95 (standard deviation = 6.16). The pooled depression prevalence (i.e., CES‐D score ≥ 16 or equivalent) was 23%. Two studies compared depression in MCI and dementia caregivers, indicating higher levels in dementia caregivers. Other outcomes, such as burden, stress, or anxiety, were only investigated by individual studies precluding pooling of data. Similarly, pooling of the data on the predictors of caregiver outcomes was impossible because of data heterogeneity. However, descriptive analysis of predictors revealed that Pearlin and colleagues' caregiver stress process model at least partially applies to the MCI context.

Conclusions

The studies reviewed were all cross sectional in design, involving clinical samples, thus limiting generalizability. Depression and psychological comorbidity, although not as pronounced as in dementia caregivers, are common complications in MCI caregivers. The long‐term course of outcomes in MCI caregivers requires further investigation.
Effects of cultured human adipose‐derived stem cells transplantation on rabbit cornea regeneration after alkaline chemical burn
Authors: Lin Hsiu‐Fen , Lai Yung‐Chang , Tai Chih‐Feng , Tsai Jin‐Lian , Hsu Huan‐Chen , Hsu Ruey‐Fen , Lu Sheng‐Nan , Feng Nan‐Hsiung , Chai Chee‐Yin , Lee Chung‐Hsun
Published: November 2012

Ocular chemical burn is a severe injury with poor outcomes. Immediate and appropriate management is highly related to prognosis. We studied the effect of cultured human adipose tissue‐derived stem cells on the regeneration of the rabbit cornea after alkaline chemical burn, using used human adipose tissue‐derived stem cells as the source material. Immediately after the chemical burn, the experimental eye received a single subconjunctival injection of a stem cell suspension (1.3 × 105 cells/0.2 mL), with the other eye serving as control. Rabbits were sacrificed and specimens taken 30 days after injection. The experimental group showed faster wound healing than the control group, and the result for the experimental group was clearer cornea medium. Histologically, there were five to six epithelial cell layers on the corneas of the experimental group as compared to two to three cell layers on the corneas of the control group. Wilcoxon signed rank test showed a significant difference in the epithelial cell layers between the two groups. Surface markers for connexin 43 (Cx43), β‐catenin, E‐cadherin, and P63 were analyzed. Cx43 and β‐catenin showed significant change, as determined by the Wilcoxon signed rank test, which indicated good cell renewal during repair of the corneal epithelium damaged by the chemical burn. E‐cadherin and P63 showed no significant change during the epithelium healing process. Transplantation of cultured human adipose tissue‐derived stem cells as a treatment for a corneal chemical burn promotes cell renewal and assists in damage repair.
Somatic evolution of head and neck cancer — Biological robustness and latent vulnerability
Authors: Masuda Muneyuki , Toh Satoshi , Wakasaki Takahiro , Suzui Masumi , Joe Andrew K.
Published: November 2012

Despite recent advancements in multidisciplinary treatments, the overall survival and quality of life of patients with advanced head and neck squamous cell carcinoma (HNSCC) have not improved significantly over the past decade. Molecular targeted therapies, which have been addressed and advanced by the concept of “oncogene addiction”, have demonstrated only limited successes so far. To explore a novel clue for clinically effective targeted therapies, we analyzed the molecular circuitry of HNSCC through the lens that HNSCC is an evolving system. In the trajectory of this somatic evolution, HNSCC acquires biological robustness under a variety of selective pressures including genetic, epigenetic, micro‐environmental and metabolic stressors, which well explains the major mechanism of “escaping from oncogene addiction”. On the other hand, this systemic view appears to instruct us approaches to target latent vulnerability of HNSCC that is masked behind the plasticity and evolvability of this complex adaptive system.
Zukunftsfähige Qualifikations- und Kompetenzprofile für Ärzte in Deutschland – Ergebnisse einer empirischen Studie
Authors: Evans Michaela , Hilbert Josef
Published: November 2012

Einleitung

Die Modernisierung des Gesundheitssystems sowie der Ruf nach mehr Innovation, Qualität und Wirtschaftlichkeit erfordern in der Praxis neue und erweitere Qualifiaktionen und Kompetenzen von Ärzten. Zahlreiche Universitäten haben mit der Reform ihrer Studiengänge der Humanmedizin begonnen. Weitere Reformen sind vor allem in den Feldern Versorgungs- und Innovationsmanagament, transprofessionelles Lernen sowie Führung notwendig.
Daily Treatment Time and Functional Gains of Stroke Patients During Inpatient Rehabilitation
Authors: Wang Hua , Camicia Michelle , Terdiman Joseph , Mannava Murali K. , Sidney Stephen , Sandel M. Elizabeth
Published: November 2012

Objective

To study the effects of daily treatment time on functional gain of patients who have had a stroke.

Design

A retrospective cohort study.

Setting

An inpatient rehabilitation hospital (IRH) in northern California.

Participants

Three hundred sixty patients who had a stroke and were discharged from the IRH in 2007.

Interventions

Average minutes of rehabilitation therapy per day, including physical therapy, occupation therapy, speech and language therapy, and total treatment.

Main Outcome Measures

Functional gain measured by the Functional Independence Measure, including activities of daily living, mobility, cognition, and the total of the Functional Independence Measure (FIM) scores.

Results

The study sample had a mean age of 64.8 years; 57.4% were men and 61.4% were white. The mean total daily therapy time was 190.3 minutes, and the mean total functional gain was 26.0. A longer daily therapeutic duration was significantly associated with total functional gain (r = .23, P = .0094). Patients who received a total therapy time of <3.0 hours per day had significantly lower total functional gain than did those treated ≥3.0 hours. No significant difference in total functional gain was found between patients treated ≥3.0 but <3.5 hours and ≥3.5 hours per day. The daily treatment time of physical therapy, occupational therapy, and speech and language therapy also was significantly associated with corresponding subscale functional gains. In addition, hemorrhagic stroke, left brain injury, earlier IRH admission, and a longer IRH stay were associated with total functional improvement.

Conclusions

The study demonstrated a significant relationship between daily therapeutic duration and functional gain during IRH stay and showed treatment time thresholds for optimal functional outcomes for patients in inpatient rehabilitation who had a stroke.
Reading Performance After Vision Rehabilitation of Subjects With Homonymous Visual Field Defects
Authors: Gall Carolin , Sabel Bernhard A.
Published: November 2012

Objective

To examine whether increased visual functioning after vision‐restoration training (VRT) coincides with improved reading abilities.

Design

Prospective noncontrolled open‐label trial.

Setting

Controlled laboratory setting for all diagnostic procedures that were conducted before and after 6 months of home‐based VRT with telemedicine support.

Patients

Eleven subjects who had experienced a posterior‐parietal stroke and have homonymous visual field defects.

Interventions

Six months of VRT (1 hour daily repeated light stimulation in the partially damaged visual field).

Main outcome measurements

VRT outcome measures were the number of detected light stimuli in eye‐tracker controlled high‐resolution perimetry and the spared visual field within the affected hemifield up to the relative and absolute defect visual field border (square degrees). Enlargements of spared visual field within the affected hemifield were correlated with changes of reading speed after VRT.

Results

After VRT, the number of detected light stimuli increased by 5.02 ± 4.31% (mean ± SD; P = .03). The spared visual field up to the relative defect visual field border increased from 18.09 ± 32.35 square degrees before to 137.40 ± 53.32 after VRT (P = .006), as well as for the absolute defect visual field border from 36.95 ± 33.77 square degrees before VRT to 152.02 ± 49.70 after VRT (P = .005). Reading speed increased from 108.95 ± 33.95 words per minute before VRT to 122.26 ± 30.35 after VRT (P = .017), which significantly correlated with increased spared visual field up to the relative defect visual field border (r = 0.73, P = .016). Measures of eye movement variability did not correlate with VRT outcome.

Conclusions

VRT improved visual fields in parafoveal areas, which are most relevant for reading. This finding cannot be explained by changes in eye movement behavior. Because of a significant association between improvements of parafoveal vision and reading speed, we propose that patients with homonymous visual field defects who have reading deficits may benefit from visual stimulation by training.
Assessment of Pelvic Floor Muscle Pressure in Female Athletes
Authors: da Silva Borin Lílian Cristina Marques , Nunes Fabiana Roberta , de Oliveira Guirro Elaine Caldeira
Published: November 2012

Objective

To evaluate the pressure of the pelvic floor muscles in female athletes and the associated signs and symptoms of stress urinary incontinence.

Design

A prospective observational study.

Setting

An academic institution, primary level of clinical care.

Participants

Forty women between 18 and 30 years of age divided into 4 groups: 10 volleyball players, 10 handball players, 10 basketball players, and 10 nonathletes.

Methods

The measurement of intracavity pressure was performed with use of a perineometer. The volunteers were instructed to perform 3 maximum isometric contractions of the perineum, held for 4 seconds. Data regarding specific training and urinary symptoms were collected through a questionnaire.

Main Outcome Measurements

Statistical analysis was performed by analysis of variance, with a significance level of 5%. The Spearman correlation was used to verify the degree of association between variables related to training, urinary symptoms, and perineal pressure.

Results

The average (standard deviation) perineal pressure for nonathletes was 6.73 ± 1.91 mm Hg. The average perineal pressure for handball players was 5.55 ± 1.43 mm Hg; for volleyball players, 4.36 ± 1.43 mm Hg; and for basketball players, 3.65 ± 1.35 mm Hg. Statistically significant differences were found in the perineal pressure of volleyball (P = .009) and basketball players (P = .039) compared with nonathletes. The number of games per year, strength training, and on‐court workout correlated significantly with perineal pressure (Spearman correlation coefficient [Rs] of −0.512 for the 3 variables). Urine leakage through effort and nocturia correlated moderately with perineal pressure (Rs of −0.51 and −0.54, respectively). A strong correlation was found between urinary frequency and perineal pressure (Rs of −0.85).

Conclusions

Analysis of these data suggests that perineal pressure is decreased in female athletes compared with nonathlete women. A lower perineal pressure correlates with increased symptoms of urinary incontinence and pelvic floor dysfunction.
Fundamental domain of invariant sets and applications
Authors: ZHANG PENGFEI
Published: November 2012

Let $X$ be a compact metric space, $f:X\to X$ a homeomorphism and $\phi \in C(X,\mathbb {R})$. We construct a fundamental domain for the set of points with finite peaks with respect to the induced cocycle $\{\phi _n\}$. As applications, we give sufficient conditions for the transitive set of a non-conservative partially hyperbolic diffeomorphism to have positive Lebesgue measure, i.e., for an accessible partially hyperbolic diffeomorphism, if the set of points with finite peaks for the Jacobian cocycle is not of full volume, then the set of transitive points is of positive volume.
Shape effects on turbulent modulation by large nearly neutrally buoyant particles
Authors: Bellani Gabriele , Byron Margaret L. , Collignon Audric G. , Meyer Colin R. , Variano Evan A.
Published: November 2012

We investigate dilute suspensions of Taylor-microscale-sized particles in homogeneous isotropic turbulence. In particular, we focus on the effect of particle shape on particle–fluid interaction. We conduct laboratory experiments using a novel experimental technique to simultaneously measure the kinematics of fluid and particle phases. This uses transparent particles having the same refractive index as water, whose motion we track via embedded optical tracers. We compare the turbulent statistics of a single-phase flow to the turbulent statistics of the fluid phase in a particle–laden suspension. Two suspensions are compared, one in which the particles are spheres and the other in which they are prolate ellipsoids with aspect ratio 2. We find that spherical particles at volume fraction ${\phi }_{v} = 0. 14\hspace{0.167em} \% $ reduce the turbulent kinetic energy (TKE) by 15 % relative to the single-phase flow. At the same volume fraction (and slightly smaller total surface area), ellipsoidal particles have a much smaller effect: they reduce the TKE by 3 % relative to the single-phase flow. Spectral analysis shows the details of TKE reduction and redistribution across spatial scales: spherical particles remove energy from large scales and reinsert it at small scales, while ellipsoids remove relatively less TKE from large scales and reinsert relatively more at small scales. Shape effects are far less evident in the statistics of particle rotation, which are very similar for ellipsoids and spheres. Comparing these with fluid enstrophy statistics, we find that particle rotation is dominated by velocity gradients on scales much larger than the particle characteristic length scales.
Amplitude and frequency modulation in wall turbulence
Authors: Ganapathisubramani B. , Hutchins N. , Monty J. P. , Chung D. , Marusic I.
Published: November 2012

In this study we examine the impact of the strength of the large-scale motions on the amplitude and frequency of the small scales in high-Reynolds-number turbulent boundary layers. Time series of hot-wire data are decomposed into large- and small-scale components, and the impact of the large scale on the amplitude and frequency of the small scales is considered. The amplitude modulation effect is examined by conditionally averaging the small-scale intensity (${ u}_{S}^{2} $) for various values of the large-scale fluctuation (${u}_{L} $). It is shown that ${ u}_{S}^{2} $ increases with increasing value of ${u}_{L} $ in the near-wall region, whereas, farther away from the wall, ${ u}_{S}^{2} $ decreases with increasing ${u}_{L} $. The rate of increase in small-scale intensity with the strength of the large-scale signal is neither symmetric (about ${u}_{L} = 0$) nor linear. The extent of the frequency modulation is examined by counting the number of occurrences of local maxima or minima in the small-scale signal. It is shown that the frequency modulation effect is confined to the near-wall region and its extent diminishes rapidly beyond ${y}^{+ } = 100$. A phase lag between the large- and small-scale fluctuations, in terms of amplitude modulation, has also been identified, which is in agreement with previous studies. The phase lag between large- and small-scale fluctuations for frequency modulation is comparable to that of amplitude modulation in the near-wall region. The combined effect of both amplitude and frequency modulation is also examined by computing conditional spectra of the small-scale signal conditioned on the large scales. In the near-wall region, the results indicate that the peak value of pre-multiplied spectra increases with increasing value of ${u}_{L} $, indicating amplitude modulation, while the frequency at which this peak occurs also increases with increasing value of ${u}_{L} $, revealing frequency modulation. The overall trends observed from the conditional spectra are consistent with the results obtained through statistical analyses. Finally, a physical mechanism that can capture most of the above observations is also presented.
Enskog kinetic theory for monodisperse gas–solid flows
Authors: Garzó V. , Tenneti S. , Subramaniam S. , Hrenya C. M.
Published: November 2012

The Enskog kinetic theory is used as a starting point to model a suspension of solid particles in a viscous gas. Unlike previous efforts for similar suspensions, the gas-phase contribution to the instantaneous particle acceleration appearing in the Enskog equation is modelled using a Langevin equation, which can be applied to a wide parameter space (e.g. high Reynolds number). Attention here is limited to low Reynolds number flow, however, in order to assess the influence of the gas phase on the constitutive relations, which was assumed to be negligible in a previous analytical treatment. The Chapman–Enskog method is used to derive the constitutive relations needed for the conservation of mass, momentum and granular energy. The results indicate that the Langevin model for instantaneous gas–solid force matches the form of the previous analytical treatment, indicating the promise of this method for regions of the parameter space outside of those attainable by analytical methods (e.g. higher Reynolds number). The results also indicate that the effect of the gas phase on the constitutive relations for the solid-phase shear viscosity and Dufour coefficient is non-negligible, particularly in relatively dilute systems. Moreover, unlike their granular (no gas phase) counterparts, the shear viscosity in gas–solid systems is found to be zero in the dilute limit and the Dufour coefficient is found to be non-zero in the elastic limit.
Triggering turbulence efficiently in plane Couette flow
Authors: Rabin S. M. E. , Caulfield C. P. , Kerswell R. R.
Published: November 2012

We use a variational formulation incorporating the full Navier–Stokes equations to identify initial perturbations with finite kinetic energy ${E}_{0} $ which generate the largest gain in perturbation kinetic energy at some time $T$ later for plane Couette flow. Using the flow geometry originally used by Butler & Farrell (Phys. Fluids A, vol. 4, 1992, pp. 1637–1650) to identify the linear transient optimal perturbations for ${E}_{0} \ensuremath{\rightarrow} 0$ and incorporating $T$ as part of the optimization procedure, we show how the addition of nonlinearity smoothly changes the result as ${E}_{0} $ increases from zero until a small but finite ${E}_{c} $ is reached. At this point, the variational algorithm is able to identify an initial condition of completely different form which triggers turbulence – called the minimal seed for turbulence. If instead $T$ is fixed at some asymptotically large value, as suggested by Pringle, Willis & Kerswell (J. Fluid Mech., vol. 703, 2012, pp. 415–443), a fundamentally different ‘final’ optimal perturbation emerges from our algorithm above some threshold initial energy ${E}_{f} \in (0, {E}_{c} )$ which shows signs of localization. This nonlinear optimal perturbation clearly approaches the structure of the minimal seed as ${E}_{0} \ensuremath{\rightarrow} { E}_{c}^{\ensuremath{-} } $, although for ${E}_{0} \lt {E}_{c} $, its maximum gain over all time intervals is always less than the equivalent maximum gain for the ‘quasi-linear optimal perturbation’, i.e. the finite-amplitude manifestation of the underlying linear optimal perturbation. We also consider a wider flow geometry recently studied by Monokrousos et al. (Phys. Rev. Lett., vol. 106, 2011, 134502) and present evidence that the critical energy for transition ${E}_{c} $ they found by using total dissipation over a time interval as the optimizing functional is recovered using energy gain at a fixed target time as the optimizing functional, with the same associated minimal seed emerging. This emphasizes that the precise form of the functional does not appear to be important for identifying ${E}_{c} $ provided it takes heightened values for turbulent flows, as postulated by Pringle, Willis & Kerswell (J. Fluid Mech., vol. 703, 2012, pp. 415–443). All our results highlight the irrelevance of the linear energy gain optimal perturbation for predicting or describing the lowest-energy flow structure which triggers turbulence.
Direct numerical simulation of free convection over a heated plate
Authors: Mellado Juan Pedro
Published: November 2012

Direct numerical simulations of free convection over a smooth, heated plate are used to investigate unbounded, unsteady turbulent convection. Four different boundary conditions are considered: free-slip or no-slip walls, and constant buoyancy or constant buoyancy flux. It is first shown that, after the initial transient, the vertical structure agrees with observations in the atmospheric boundary layer and predictions from classical similarity theory. A quasi-steady inner layer and a self-preserving outer layer are clearly distinguished, with an overlap region between them of constant turbulent buoyancy flux. The extension of the overlap region reached in our simulations is more than 100 wall units$ \mathop{ ({\kappa }^{3} / {B}_{s} )}\nolimits ^{1/ 4} $, where${B}_{s} $is the surface buoyancy flux and$\kappa $the corresponding molecular diffusivity (the Prandtl number is one). The buoyancy fluctuation inside the overlap region already exhibits the$\ensuremath{-} 1/ 3$power-law scaling with height for the four types of boundary conditions, as expected in the local, free-convection regime. However, the mean buoyancy gradient and the vertical velocity fluctuation are still evolving toward the corresponding power laws predicted by the similarity theory. The second major result is that the relation between the Nusselt and Rayleigh numbers agrees with that reported in Rayleigh–Bénard convection when the heated plate is interpreted as half a convection cell. The range of Rayleigh numbers covered in the simulations is then$5\ensuremath{\times} 1{0}^{7} \text{{\ndash}} 1{0}^{9} $. Further analogies between the two problems indicate that knowledge can be transferred between steady Rayleigh–Bénard and unsteady convection. Last, we find that the inner scaling based on$\{ {B}_{s} , \hspace{0.167em} \kappa \} $reduces the effect of the boundary conditions to, mainly, the diffusive wall layer, the first 10 wall units. There, near the plate, free-slip conditions allow stronger mixing than no-slip ones, which results in 30 % less buoyancy difference between the surface and the overlap region and 30–40 % thinner diffusive sublayers. However, this local effect also entails one global, substantial effect: with an imposed buoyancy, free-slip systems develop a surface flux 60 % higher than that obtained with no-slip walls, which implies more intense turbulent fluctuations across the whole boundary layer and a faster growth.
A flow in the depth of infinite annular cylindrical cavity
Authors: Shtern Vladimir
Published: November 2012

The paper describes an asymptotic flow of a viscous fluid in an infinite annular cylindrical cavity as the distance from the flow source tends to infinity. If the driving flow near the source is axisymmetric then the asymptotic pattern is cellular; otherwise it is typically not. Boundary conditions are derived to match the asymptotic axisymmetric flow with that near the source. For a narrow cavity, the asymptotic solutions for the axisymmetric and three-dimensional flows are obtained analytically. For any gap, the flow is described by a numerical solution of an eigenvalue problem. The least decaying mode corresponds to azimuthal wavenumber $m= 1$.
Hydrodynamic interactions among multiple circular cylinders in an inviscid flow
Authors: Sun R. , Ng C. O.
Published: November 2012

Hydrodynamic interactions among multiple circular cylinders translating in an otherwise undisturbed inviscid fluid are theoretically investigated. A constructive method for solving a Neumann boundary-value problem in a domain outside$N$circles (one kind of Hilbert boundary-value problem in the complex plane) is presented in the study to derive the velocity potential of the liquid. The method employs successive offset functions combined with a ‘generalized cyclic permutation’ in turn to satisfy the impenetrable boundary condition on each circle. The complex potential is therefore expressed as$N$isolated singularities in power series form and used to get instantaneous added masses of$N$submerged circular cylinders. Then, based on the Hamilton variational principle, a dynamical equation of motion in vector form is derived to predict nonlinear translations of the submerged bodies under fully hydrodynamic interactions. Also, the equivalence of the energy-based Lagrangian framework and a momentum-type one in the two-dimensional body–liquid system is proved. It implies that the pressure integration around a submerged body is holographic, which provides information about velocities and accelerations of all bodies. The numerical solutions indicate some typical dynamical behaviours of more than two circular cylinders which reveal that interesting nonlinear phenomena would appear in such a system with simple physical assumptions.
Exact solutions for wave propagation over a patch of large bottom corrugations
Authors: Yu Jie , Zheng Guangfu
Published: November 2012

Applying the Floquet theory for linear motions (Howard & Yu, J. Fluid Mech., vol. 593, 2007, pp. 209–234) to the problem of wave propagation over a patch of periodic bottom corrugations in an otherwise flat seabed, we show that exact solutions to this scattering problem can be constructed without any constraint on the bottom amplitude and/or slope. These solutions are able to describe both the slowly and fast varying aspects of the flow, in contrast to the analyses based on the general ideas of slowly varying waves. We use as an example the well-studied Bragg scattering by a patch of bottom corrugations to present some quantitative results and comparisons with experimental data.
Flow of power-law fluids in fixed beds of cylinders or spheres
Authors: Singh John P. , Padhy Sourav , Shaqfeh Eric S. G. , Koch Donald L.
Published: November 2012

An ensemble average of the equations of motion for a Newtonian fluid over particle configurations in a dilute fixed bed of spheres or cylinders yields Brinkman’s equations of motion, where the disturbance velocity produced by a test particle is influenced by the Newtonian fluid stress and a body force representing the linear drag on the surrounding particles. We consider a similar analysis for a power-law fluid where the stress $\boldsymbol{\tau} $ is related to the rate of strain $ \mathbisf{e} $ by $\boldsymbol{\tau} = 2m \mathop{ \vert \mathbisf{e} \vert }\nolimits ^{n\ensuremath{-} 1} \mathbisf{e} $, where $m$ and $n$ are constants. In this case, the ensemble-averaged momentum equation includes a body force resulting from the nonlinear drag exerted on the surrounding particles, a power-law stress associated with the disturbance velocity of the test particle, and a stress term that is linear with respect to the test particle’s disturbance velocity. The latter term results from the interaction of the test particle’s velocity disturbance with the random straining motions produced by the neighbouring particles and is important only in shear-thickening fluids where the velocity disturbances of the particles are long-ranged. The solutions to these equations using scaling analyses for dilute beds and numerical simulations using the finite element method are presented. We show that the drag force acting on a particle in a fixed bed can be written as a function of a particle-concentration-dependent length scale at which the fluid velocity disturbance produced by a particle is modified by hydrodynamic interactions with its neighbours. This is also true of the drag on a particle in a periodic array where the length scale is the lattice spacing. The effects of particle interactions on the drag in dilute arrays (periodic or random) of cylinders and spheres in shear-thickening fluids is dramatic, where it arrests the algebraic growth of the disturbance velocity with radial position when $n\geq 1$ for cylinders and $n\geq 2$ for spheres. For concentrated random arrays of particles, we adopt an effective medium theory in which the drag force per unit volume in the medium surrounding a test particle is assumed to be proportional to the local volume fraction of the neighbouring particles, which is derived from the hard-particle packing. The predictions of the averaged equations of motion are validated by comparison with simulations of randomly distributed hydrodynamically interacting cylinders.
Anti-Plane Interaction between a Crack and an Elliptically Cylindrical Layered Media
Authors: Chao C.K. , Wikarta A.
Published: November 2012

Anti-plane interaction of an elliptically cylindrical layered media with an arbitrarily oriented crack embedded in an infinite matrix, intermediate layer, or inner inclusion under a remote uniform shear load is considered in this paper. Based on the technique of conformal mapping and the method of analytical continuation in conjunction with the alternating technique, the solution for a screw dislocation in the inclusions and the matrix is first derived in a series form. The integral equations with logarithmic singular kernels for a line crack can easily be obtained by using the screw dislocation solutions as the Green's function together with the principle superposition. The stress intensity factors, which can properly reflect the interaction between a crack and an elliptically cylindrical layered media, are then obtained numerically in terms of the values of the dislocation density functions of the integral equations. The effects of material property combinations and geometric parameters on the normalized mode-III stress intensity factors are discussed in detail and shown in graphic form.