bluuebunny/crossref_metadata_2025 huggingface dataset:
Locomotion and contraction in an asconoid calcareous sponge
Authors: Bond Calhoun
Published: November 2013

Various large‐scale behaviors (e.g., locomotion, shape changes, contractions) have been documented numerous times in intact sponges of the class Demospongiae. However, little is known about such motile events in calcareous sponges (Class Calcarea). Here, we report on whole‐sponge behaviors of the calcareous asconoid sponge Leucosolenia botryoides, as revealed by time‐lapse videos. These behaviors included locomotion and contraction. Locomotion in these sponges appeared as an outward movement (25–130 μm h−1) of the asconoid tubes away from the sponge's center; such translocations were always accompanied by extensive movements of protruding spicules, which appear to act as anchoring hooks for the sponge's translocations. This is the first report of whole‐sponge locomotion in the Calcarea. Contractile waves also were propagated in these sponges at speeds of 50–150 μm h−1, and they involved systemic contraction, then re‐extension of the asconoid tubes. The observations suggest that, like the more complex demosponges, these simple calcareous sponges are capable of adaptive whole‐animal behaviors (changes in flow, shape, and location), which occur in response to environmental stimuli such as crawling intruders.
Climate change shifts environmental space and limits transferability of treeline models
Authors: Schibalski Anett , Lehtonen Aleksi , Schröder Boris
Published: November 2013

Our study aims at gaining insights into the processes determining the current treeline dynamics in Finnish Lapland. Using forest surveys conducted in 1978 and 2003 we modelled the occurrence and abundance of three dominant tree species in Finnish Lapland, i.e. Pinus sylvestris, Picea abies and Betula pubescens, with boosted regression trees. We assessed the importance of climatic, biotic and topographic variables in predicting tree occurrence and abundance based on their relative importance and response curves. We compared temporal and spatial transferability by using an extended transferability index.

Site fertility, the abundance of co‐occurring species and growing degree days were generally the most important predictors for both occurrence and abundance across all species and datasets. Climatic predictors were more important for modelling occurrences than for modelling abundances. Occurrence models were able to reproduce the observed treeline pattern within one time period or region. Abundance models underestimated basal area but captured the general pattern of low and high values. Model performance as well as transferability differed considerably between species and datasets. Pinus sylvestris was modelled more successfully than P. abies and B. pubescens. Generally, spatial transferability was greater than temporal transferability. Comparing the environmental space between datasets revealed that transferring models means extrapolating to novel environments, providing a plausible explanation for limited transferability.

Our study illustrates how climate change can shift the environmental space and lead to limited model transferability. We identified non‐climatic factors to be important in predicting the distribution of dominant tree species, contesting the widespread assumption of climatically induced range expansion.
Number of teeth, C‐reactive protein, fibrinogen and cardiovascular mortality: a 15‐year follow‐up study in a Finnish cohort
Authors: Janket Sok‐Ja , Baird Alison E. , Jones Judith A. , Jackson Elizabeth A. , Surakka Markku , Tao Wen , Meurman Jukka H. , Van Dyke Thomas E.
Published: November 2013

Aim

To test whether the number of teeth, an inverse proxy for composite oral infection scores is associated with better survival.

Materials and Methods

The Kuopio Oral Health and Heart study initiated a case–control study in 1995–1996 consisting of 256 consecutive coronary artery disease patients and 250 age and gender‐matched controls. We appended the mortality data and formulated a longitudinal study. By May 31st, 2011, 124 mortalities had occurred and 80 of which were of cardiovascular origin. Using Cox proportional hazards models, we assessed the association of the teeth group (Teethgrp) – consisting of 10 teeth – with cardiovascular and all‐cause mortality after 15.8 years of median follow‐up.

Results

In multivariate models, with the edentulous state as reference, one level increase in Teethgrp was associated with significantly increased survival from cardiovascular disease (CVD) mortality with a Hazard Ratio (HR) 0.73, p‐value = 0.02 but not with all‐cause mortality (HR = 0.87, p = 0.13). The findings were not mediated by C‐reactive protein (CRP) levels ≥3 mg/L or by median fibrinogen levels, but were mediated by CRP levels >5 mg/L.

Conclusion

Each increment of 10 teeth from the edentulous state was associated with a 27% improved CVD survival, independent of low‐grade systemic inflammation.
Assessing Lesbian, Gay, and Bisexual Affirmative Training in Couple and Family Therapy: Establishing the Validity of the Faculty Version of the Affirmative Training Inventory
Authors: McGeorge Christi R. , Carlson Thomas S. , Toomey Russell B.
Published: November 2013

This study established the validity and factor structure of the Faculty Version of the Affirmative Training Inventory (ATI‐F), which assesses faculty members’ perceptions of the level of lesbian, gay, and bisexual (LGB) affirmative training that occurs in clinical programs. Additionally, this study examined the latent associations among the subscales of the ATI‐F and three convergent validity items utilizing a sample of 117 faculty members from accredited family therapy programs. The findings provide empirical support for the relationship between including classroom content on LGB affirmative therapy and faculty members’ beliefs about LGB individuals and relationships. Specifically, faculty members who report more positive beliefs about LGB clients appear to be more likely to include LGB affirmative therapy content in the courses they teach.
Identification of Races and Mating Types of Cochliobolus carbonum from Corn in the Yunnan Province in China
Authors: Lu Canhua , Wu Yixin , Ho Honhing , Mao Zichao , He Yueqiu
Published: November 2013

Northern corn leaf spot, a foliar disease caused by Cochliobolus carbonum, has become prevalent in southwestern China, especially in the Yunnan Province. Races and mating types were identified for 169 isolates collected from 13 prefectures of Yunnan by artificial inoculation using six hybrid corns as differential hosts and by crossing with three standard mating strains: CC092 (MAT1‐2), CC120 (MAT1‐1) and CC026 (MAT1‐1). Results showed the existence of three races: CCR1 (one isolate), CCR2 (43 isolates) and CCR3 (125 isolates). Most isolates were moderately or weakly virulent with only five being highly virulent. CCR3 was widely distributed and significantly more virulent than CCR2 that coexisted with CCR3 in many locations. On Sach's nutrient agar, 20.71% of the Yunnan isolates self‐mated, forming sterile perithecia. Fully developed perithecia could be formed between isolates of different geographic origins, but only 15.98% strains mated successfully with CC092 and 5.33% formed mature perithecia with 4–6 ascospores per asus. Similar results were obtained in crossing with CC026 or CC120. Mating could also occur between CCR3 and CCR2. Both mating types were found in Yunnan with 84 MAT1‐1 strains (one CCR1, 10 CCR2 and 73 CCR3) and 85 MAT1‐2 strains (33 CCR2 and 52 CCR3) and they coexisted in most areas. To identify the mating type rapidly, three specific primers were successfully developed and employed to amplify the mating‐type genes, with stable patterns of 1627 and 876 bp fragments obtained from MAT1‐1 and MAT1‐2 isolates, respectively. The ratio between MAT1‐1 and MAT1‐2 was 1 : 1, indicating that the mating‐type genes segregated randomly in the field naturally.
Morphometry of the Pelvic Floor Muscles in Women With and Without Provoked Vestibulodynia Using 4D Ultrasound
Authors: Morin Mélanie , Bergeron Sophie , Khalifé Samir , Mayrand Marie-Hélène , Binik Yitzchak M.
Published: November 2013

Introduction

It has been suggested that pelvic floor muscles (PFMs) play an important role in provoked vestibulodynia (PVD) pathophysiology. Controversy in determining their exact contribution may be explained by methodological limitations related to the PFM assessment tools, specifically the pain elicited by the measurement itself, which may trigger a PFM reaction and introduce a strong bias.

Aim

The aim of this study was to compare PFM morphometry in women suffering from PVD to asymptomatic healthy control women using a pain-free methodology, transperineal four-dimensional (4D) ultrasound.

Methods

Fifty-one asymptomatic women and 49 women suffering from PVD were recruited. Diagnosis of PVD was confirmed by a gynecologist following a standardized examination. All the participants were nulliparous and had no other urogynecological conditions. The women were evaluated in a supine position at rest and during PFM maximal contraction.

Main Outcome Measures

Transperineal 4D ultrasound, which consists of a probe applied on the surface of the perineum without any vaginal insertion, was used to assess PFM morphometry. Different parameters were assessed in sagittal and axial planes: anorectal angle, levator plate angle, displacement of the bladder neck, and levator hiatus area. The investigator analyzing the data was blinded to the clinical data.

Results

Women with PVD showed a significantly smaller levator hiatus area, a smaller anorectal angle, and a larger levator plate angle at rest compared with asymptomatic women, suggesting an increase in PFM tone. During PFM maximal contraction, smaller changes in levator hiatus area narrowing, displacement of the bladder neck, and changes of the anorectal and of the levator plate angles were found in women with PVD compared with controls, which may indicate poorer PFM strength and control.

Conclusion

Using a reliable and pain-free methodology, this research provides sound evidence that women with PVD display differences in PFM morphometry suggesting increased tone and reduced strength.
A Causality Analysis of Economic Growth and Union Density inEuropean Countries
Authors: Jaoul‐Grammare Magali , Terraz Isabelle
Published: November 2013

In this paper, we analyse the relationship between union density and economic growth using aGranger causality analysis and shocks analysis with vector autoregression model. We find that theGranger causality goes from the growth rate to the unionization rate in four of the 11European countries under study.France bucks the trend: it is the only country in which union density influences economic growth, moreover in a positive way.
Control of experimental Triatoma infestans populations: effect of pour‐on cypermethrin applied to chickens under natural conditions in the Argentinean Chaco region
Authors: AMELOTTI I. , CATALÁ S. S. , GORLA D. E.
Published: November 2013

Among peridomestic structures, chicken coops are sites of major importance for the domestic ecology of Triatoma infestans (Hemiptera: Reduviidae). The aim of this study was to evaluate in an experimental context the effects of a cypermethrin pour‐on formulation applied to chickens on blood intake, moulting and mortality in T. infestans, under the natural climatic conditions of a region endemic for Chagas' disease. Experimental chicken huts were made of bricks and covered with plastic mosquito nets. Ninety fourth‐instar nymphs were maintained in each hut. The study used a completely random design in which chickens in the experimental group were treated with a cypermethrin pour‐on formulation. Five replicates (= huts) of the experimental and control groups were conducted. The number of live T. infestans, blood intake and moults to fifth‐instar stage were recorded at 1, 5, 20, 35 and 45 days after the application of cypermethrin. Cumulative mortality was higher in nymphs exposed to treated chickens (> 71%) than in control nymphs (< 50%) (P < 0.01). Blood intake and moulting rate were lower in nymphs fed on treated chickens than in control nymphs (P < 0.05). Pour‐on cypermethrin was able to cause significant mortality, although it did not eliminate the experimental population of T. infestans.
Effect of Short‐Term Scrotal Hyperthermia on Spermatological Parameters, Testicular Blood Flow and Gonadal Tissue in Dogs
Authors: Henning H , Masal C , Herr A , Wolf K , Urhausen C , Beineke A , Beyerbach M , Kramer S , Günzel‐Apel A‐R
Published: November 2013

Contents

The objective was to assess the effect of a short‐term scrotal hyperthermia in dogs on quantitative and qualitative ejaculate parameters, testicular blood flow and testicular and epididymal histology. After a control period, the scrotum of seven normospermic adult beagle dogs was insulated with a self‐made suspensory for 48 h. Nine weeks later, two animals were castrated, while in five animals, scrotal hyperthermia was repeated. Dogs were castrated either 10 or 40 days thereafter. In each phase of scrotal insulation, average scrotal surface temperature increased by 3.0°C. Semen was collected twice weekly throughout the experiment. Total sperm count did not change after the first hyperthermia, but it slightly decreased after the second (p < 0.05). Profiles of sperm morphology and velocity parameters (CASA) rather indicated subtle physiological variations in sperm quality than effects of a local heat stress. Chromatin stability of ejaculated spermatozoa as indicated by SCSA remained constant throughout the experiment. Perfusion characteristics of the gonads, that is, systolic peak velocity, pulsatility and resistance index at the marginal location of the testicular artery, did not change due to hyperthermia (p > 0.05). Histological examination of excised testes and epididymides for apoptotic (TUNEL and activated caspase‐3) and proliferating cells (Ki‐67 antigen) indicated only marginal effects of scrotal insulation on tissue morphology. In conclusion, a mild short‐term scrotal hyperthermia in dogs does not cause substantial changes in sperm quantity and quality. In contrast to other species, canine testes and epididymides may have a higher competence to compensate such thermal stress.
Enrichment of Y‐Chromosome‐Bearing Bull Spermatozoa by Swim‐up Through a Column
Authors: Azizeddin A , Ashkar FA , King WA , Revay T
Published: November 2013

Contents

With the advancement of assisted reproductive biotechnologies, preselecting the sex of offspring has become an important goal for cattle and other livestock breeding as well as for research. The aim of this study was to investigate the feasibility of producing enriched pools of X‐ or Y‐chromosome‐bearing sperm by vertical swim‐up through a long, narrow column. Sperm recovered from the top portion of the column was predominantly Y‐bearing (60%, p < 0.05), which were capable of fertilizing matured oocytes and produce significantly more male embryos compared with standard swim‐up protocol.
Interpolating the Lorenz Curve: Methods to Preserve Shape and Remain Consistent with the Concentration Curves for Components
Authors: Okamoto Masato
Published: November 2013

C1‐class interpolation methods that preserve monotonicity and convexity and are thus suitable for the estimation of the Lorenz curve from grouped data are not widely known. Instead, parametric models are usually applied for such estimation. Parametric models, however, have difficulty in accurately approximating every part of income/expenditure distributions. This paper proposes two types of C1‐class shape‐preserving interpolation methods. One is a piecewise rational polynomial interpolation (proposed independently by Stineman and Delbourgo) that enables consistent interpolation of the concentration curves for income/expenditure components, attaining approximately the same accuracy as that of the existing methods when applied to decile‐grouped data or to more detailed aggregation. Another is a Hybrid interpolation that employs pieces of curves derived from parametric models on end intervals. Empirical comparisons show that the Hybrid interpolation (with the assistance of parametric models for class‐boundary estimation) outperforms the existing methods even when applied to quintile‐grouped data without class boundaries.
Inflation Targeting in ASEAN‐10
Authors: Poon Wai Ching , Lee Yong Shen
Published: November 2013

The paper addresses the empirical question of whether economies that do not systematically target inflation (non‐inflation targeters) experience higher exchange rate volatility as compared with inflation targeters in 10 countries of the Association of Southeast Asian Nation (ASEAN) from 1990 to 2010. The paper examines the role of real exchange rate, exchange rate volatility and the reaction functions of central banks using dynamic panel estimation techniques. The results indicate that the output gap offers more useful information than the inflation gap in setting interest rates for inflation targeters, implying that the real term is more important than the nominal term. In turn, this suggests that an increase in interest rate can be wielded swiftly to reduce real gross domestic product and suppress inflation. The real exchange rate appears as a weaker determinant in setting interest rates for non‐inflation targeters. Inflation targeters experienced lower exchange rate volatility compared with non‐targeters in the ASEAN, which implies that implementation costs to their domestic economies may be marginally lower. Meanwhile, the non‐targeters follow a mixed strategy as both the inflation and real exchange rate are used as instruments to set the interest rates.
Evaluation of rebound tonometry in red‐eared slider turtles (Trachemys scripta elegans)
Authors: Delgado Cherlene , Mans Christoph , McLellan Gillian J. , Bentley Ellison , Sladky Kurt K. , Miller Paul E.
Published: November 2013

Objective

To evaluate feasibility and accuracy of intraocular pressure (IOP) measurement by rebound tonometry in adult red‐eared slider turtles and determine the effects of manual and chemical restraint onIOP.

Animal studied

Seventeen adult red‐eared slider turtles.

Procedures

Intraocular pressure was measured with TonoLab®and TonoVet®tonometers in conscious, unrestrained turtles. To evaluate the effects of manual restraint, turtles were restrained by digital pressure on the rostral head or proximal neck. The effect of two chemical restraint protocols (dexmedetomidine, ketamine, midazolam [DKM] and dexmedetomidine, ketamine [DK] subcutaneously) onIOPwas evaluated. Triplicate TonoLab®and TonoVet®readings were compared with direct manometry in threeex vivoturtle eyes.

Results

TonoLab®correlated better with manometry atIOPs < 45 mmHg than TonoVet®(linear regression slopes of 0.89 and 0.30, respectively). Mean (±SD)IOPin unrestrained conscious turtles was significantly lower (P < 0.01) with TonoLab®(10.02 ± 0.66 mmHg) than with TonoVet®(11.32 ± 1.57 mmHg). Manual neck restraint caused a significant increase inIOP(+6.31 ± 5.59 mmHg), while manual rostral head restraint did not. Both chemical restraint protocols significantly reducedIOP(DKM: −1.0 ± 0.76 mmHg;DK: −1.79 ± 1.17) compared with measurements in conscious unrestrained turtles.

Conclusions

Chemical and manual neck restraint affectedIOP. Rostral head restraint had no significant effect onIOPand is, therefore, recommended as the appropriate restraint technique in red‐eared slider turtles. TonoLab®measurements estimated actualIOPmore accurately, within physiologic range, than measurements obtained using the TonoVet®.
The Effect of a Pressure-Containing Correlation Model on Near-Wall Flow Simulations With Reynolds Stress Transport Models
Authors: Poroseva Svetlana V.
Published: November 2013

It is accustomed to think that turbulence models based on solving the Reynolds-averaged Navier–Stokes (RANS) equations require empirical functions to accurately reproduce the behavior of flow characteristics of interest, particularly near a wall. The current paper analyzes how choosing a model for pressure-strain correlations in second-order closures affects the need for introducing empirical functions in model equations to reproduce the flow behavior near a wall correctly. An axially rotating pipe flow is used as a test flow for the analysis. Results of simulations demonstrate that by using more physics-based models to represent pressure-strain correlations, one can eliminate wall functions associated with such models. The higher the Reynolds number or the strength of imposed rotation on a flow, the less need there is for empirical functions regardless of the choice of a pressure-strain correlation model.
Verification and Validation of an Open Source–Based Morphology Analysis Platform to Support Implant Design
Authors: Bischoff Jeffrey E. , Davis Brad , Seebeck Jörn , Henderson Adam , Zuhars Joel , Marion Pat , Goodlett Casey
Published: November 2013

Availability of medical image data and ongoing advancement of image-processing and mathematical-modeling techniques are increasingly enabling device manufacturers to conduct clinically relevant morphological and mechanical analyses across populations to support device development. Gaps in the ability of contemporary commercial codes to fully realize these analytical goals frequently requires some amount of in-house code development and deployment. Verification and validation (V&V) of these custom modules or platforms is an essential requirement for deployment of the software within a medical device design controls system. One such software platform to support orthopedic morphological analysis, zibra, has been successfully developed through a collaborative relationship between Zimmer, Inc. and Kitware, Inc. The development process involved configuration of commercial code, open-source toolkits, and custom code. Here, the V&V strategy to support deployment of zibra is described.
Computational Analysis of the Electro-Mechanical Activation Sequence of the Myocardium
Authors: Marcé-Nogué Jordi , Roure Francesc , Fortuny Gerard
Published: November 2013

In 1975 the valencian cardiologist F. Torrent-Guasp described the heart as a Helical Ventricular Myocardial Band (HVMB) in which “The ventricular myocardium is presented when it is unrolled under the form of a single big muscular band that, due to its special disposition, describes two cavities in the intact heart” [1]. It gives a different perspective of the morphology of the heart than the current and it could explain better and most coherently the propagation of the electrical stimulus which activates the shortening of the fibres, the complex deformation movement of the heart and maybe an explanation about understanding the cardiac contraction.
Structural Deformation of Native Aortic Valve Leaflet Under Hypertension: An In Vitro Study
Authors: Yap C. H. , Kim H. S. , Dasi L. P. , Weiler M. J. , Balachandran K. , Haj-Ali R. , Yoganathan A. P.
Published: November 2013

The aortic valve (AV) is a complex structure that functions in a complex dynamic environment. During systole, the valve leaflets bend at the base to open and experience fluid shear stress on both ventricular and aortic sides of the leaflet. During diastole, adverse pressure gradient closes the valve causing it to structurally support the systemic afterload pressure. Ex vivo experiments has shown that isolated mechanical forces such as pressure, membrane tension, and fluid shear stress affects the remodeling activities of the valve leaflets and also elicit pathological responses [1], potentially leading to calcific aortic valve disease in the long term. Clinically, patients with hypertension have increased risk of developing calcific aortic valve disease [2], which could be a result of the increased pressure or the increased stretch on the valve leaflets.
A Relation Between Particle Hemodynamics and Intraluminal Thrombus Formation in Abdominal Aortic Aneurysms
Authors: Basciano Christopher A. , Ng Julie H. Y. , Finol Ender A. , Kleinstreuer Clement
Published: November 2013

Abdominal aortic aneurysms (AAAs) are local dilations of the aorta below the renal arteries where the lumen diameter is ≥ 1.5 times the normal diameter of the healthy blood vessel. Ruptured aneurysms are the 13th leading cause of death in the US [1]. In approximately 75% of all AAAs, a particle-deposition layer forms adjacent to the arterial wall within the lumen called the intra-luminal thrombus (ILT). The thrombus composition has been shown to be a fibrin structure composed of blood cells, platelets, blood proteins, and other cellular debris [2]. Additionally, Yamazumi et al. [3] have presented data that suggest AAA morphology is associated with an elevated state of blood coagulation and fibrinolysis within the aneurysm.
Influence of Distal Resistance and Proximal Vascular Stiffness on Vascular Impedance and Hemodynamics in Pulmonary Hypertension: A Computational Study With Validation Using an Animal Model
Authors: Su Zhenbi , Hunter Kendall , Tan Wei , Shandas Robin
Published: November 2013

Clinically, invasive measurement of pulmonary vascular flow and pressure provides the hemodynamic status of the pulmonary circulation with pulmonary arterial hypertension (PAH). Current diagnostics and therapeutics for PAH revolve around pulmonary vascular resistance (PVR), which is determined by the mean pressure divided by mean flow [1]. Though PVR correlates well with right ventricular (RV) afterload, failure of which is the primary determinant of mortality [2–4], PVR does not provide the complete measure of RV afterload since it neglects dynamic impedance effects [4, 5]. Although we have shown that impedance predicts clinical outcomes better than PVR alone, several key questions remain about the relationship between hemodynamics and impedance changes in pulmonary hypertension.
Remote Control of Apical Epithelial Sheet Contraction by Laser Ablation or Nano-Perfusion: Acute Stimulus Triggers Rapid Remodeling of F-Actin Network in Apical Cortex
Authors: Joshi Sagar D. , Davidson Lance A.
Published: November 2013

Apical contraction is the major tissue movement during remodeling of epithelial sheets in development. During apical contraction, groups of cells narrow their apices to form bottle-shaped structures, driving events such as sea-urchin gastrulation [1], Drosophila ventral-furrow formation, vertebrate neurulation and wound healing [2]. Tissue-folding events such as invagination, ingression and involution involve this tissue movement in which cells actively build “rifts” and “tubes”. Epithelial cells integrate genetic information, mechanical signals, and biochemical gradients to build these structures, but how they do so is unknown [3]. Theoretical models [4] provide some mechanical explanation for these events. Here we experimentally induce apical contractions controllably for the first time in amphibian embryos. Two independent methods, namely, laser ablation of cell membranes and nano-perfusion with cell lysate induce cell contraction in tissue isolates and in whole embryos. We demonstrate a biochemical pathway that stimulates rapid actin-reorganization/ polymerization accompanied by increases in α-actinin. The F-actin remodeling correlates with increased levels of Ca++. Cell contraction begins within few seconds of laser ablation or nano-perfusion, peaks within a minute and is followed by a similar relaxation. Acute control of epithelial mechanics will allow us to better understand how molecular genetic processes drive shape change in tissues and will help future bioengineers build complex 3D epithelial organs.
Meniscal Movement During the Gait Cycle Is Sensitive to the Attachment Properties of the Meniscal Horns
Authors: Netravali Nathan A. , Giori Nicholas J. , Andriacchi Thomas P.
Published: November 2013

The menisci are integral structures within the knee that help provide conforming surfaces between the femoral and tibial cartilage by moving as the knee flexes and thus reducing the contact stresses on the articular cartilage in the knee throughout the knee’s wide range of motion [1]. The menisci are firmly rooted in the tibial plateau at the anterior and posterior horns with more lax attachment in central regions. Thus, the stiffness of these meniscal attachments at the horns is an important consideration when evaluating meniscal function. Hence it is crucial to properly represent the attachment of the menisci at the anterior and posterior horns when evaluating normal motion of the menisci during knee movement. While finite element (FE) models of the tibio-menisco-femoral joint have been useful tool in evaluating meniscal function, previous FE models [2–5] of the knee joint that include the meniscus have not addressed the movement of the menisci during daily activities. Yet it is precisely this mobility of the menisci that permits them to adapt to the movement of the articular surfaces during typical activities and prevent injuries. Thus, the objective of this study was to simulate meniscal motion during a portion of the gait cycle and investigate the sensitivity of meniscal attachment stiffness using a finite element model. A previously established method [4] for attaching the meniscal horns to the tibia was used and its material properties were varied to determine the sensitivity of the movement of the menisci to the properties of the attachments at the horns.
Hand/Handhold Coupling: Influence of Active Grip Force and Friction on Breakaway Strength
Authors: Young Justin G. , Woolley Chuck B. , Armstrong Thomas J. , Ashton-Miller James A.
Published: November 2013

Fall-related fatalities and injuries during climbing tasks represent a significant socioeconomic problem whether they occur in children, in the working age population, or in the elderly. The strength of the mechanical coupling between hand and handhold largely determines if a person can support their bodyweight or will lose grip of the handhold, fall and risk injury. It therefore seems prudent to quantify the maximum amount of external force that the coupling between the hand and handhold is capable of withstanding and to determine how handle design properties influence this.
Validation of Abdominal Aortic Aneurysm Dynamics: A Comparative Analysis of PIV, CFD, and FSI
Authors: Scotti Christine M. , Shu Fangjun , Vandenberghe Stijn , Seong Jaehoon , Antaki James F. , Lieber Baruch B. , Finol Ender A.
Published: November 2013

Flow visualization techniques provide the opportunity to observe the fluid dynamics phenomena that occur in vascular geometries under specific, known conditions. These conditions can then be used to calibrate computational models of identical geometries, a validation that is useful in the assessment of prospective interventions and perturbations. The present study investigated the flow dynamics within both a rigid abdominal aortic aneurysm (AAA) model with an iliac bifurcation and a compliant replica. Velocity fields were experimentally measured in vitro using particle image velocimetry (PIV) and compared with transient CFD and FSI analyses. The results show that the CFD approach is able to predict the patterns of flow from the PIV experiments, which arise from the geometry of the AAA. The FSI representation of the compliant wall PIV experiments showed that the in-plane dynamics visualized by PIV matched by FSI in a qualitative manner. Wall deformation, assessed by means of diameter changes in the cardiac cycle at the midsection of the compliant AAA model, was matched by the FSI analysis with a maximum relative difference of 8%.
MD simulations of low energy Clx+ ions interaction with ultrathin silicon layers for advanced etch processes
Authors: Brichon Paulin , Despiau-Pujo Emilie , Joubert Olivier
Published: November 2013

Molecular dynamics simulations of low-energy (5–100 eV) Cl+ and Cl2+ bombardment on (100) Si surfaces are performed to investigate the impact of plasma dissociation and very low-energy ions (5–10 eV) in chlorine pulsed plasmas used for silicon etch applications. Ion bombardment leads to an initial rapid chlorination of the Si surface followed by the formation of a stable SiClx mixed layer and a constant etch yield at steady state. The SiClx layer thickness increases with ion energy (from 0.7 ± 0.2 nm at 5 eV to 4 ± 0.5 nm at 100 eV) but decreases for Cl2+ bombardment (compared to Cl+), due to the fragmentation of Cl2+ molecular ions into atomic Cl species with reduced energies [one X eV Cl + <−> two 2X eV Cl2+]. The Si etch yield is larger for Cl2+ than Cl+ bombardment at high-energy (Ei > 25 eV) but larger for Cl+ than Cl2+ bombardment at low-energy (Ei < 25 eV) due to threshold effects. And the higher the ion energy, the less saturated the etch products. Results suggest that weakly dissociated chlorine plasmas (containing more Cl2+ than Cl+ ions) should lead to thinner SiClx mixed layers and lower Si etch yields if ion energies remains below 25 eV, which confirms the potential of pulsed plasmas to address etching challenges of ultrathin films transistors, in which slow etch rates and very controlled processes are required.
A focused electric spark source for non-contact stress wave excitation in solids
Authors: Dai Xiaowei , Zhu Jinying , Haberman Michael R.
Published: November 2013

A focused electric spark is used as a non-contact acoustic source to excite stress waves in solids. The source consists of an electric spark source located at the near focus of an ellipsoidal reflector that focuses the acoustic disturbance generated by the spark source to the far focal point. Experimental studies using both contact and non-contact sensors indicate that the source has the capability to excite the Rayleigh surface wave and impact-echo mode (S1-zero-group-velocity Lamb mode) in a 250 mm thick concrete slab and to enable fully air-coupled testing of concrete specimens.
Effect of temporal modulation rate on the intelligibility of phase-based speech
Authors: Chen Fei , Guan Tian
Published: November 2013

This study investigated the effect of temporal modulation rate on the intelligibility of speech synthesized with primarily phase information using two methods: Phase-based vocoded speech (preserving phase cues and discarding envelope cues) and Hilbert fine-structure stimuli (summing up the multi-channel Hilbert fine-structure waveforms). Listening experiments with normal-hearing participants showed that the intelligibility of the two types of phase-based speech was significantly improved when synthesized using a high temporal modulation rate (or short frame) compared to that synthesized using the whole speech segment. This intelligibility advantage appears to be attributed to better preservation of the temporal envelope cues in phase-based speech.
A Microchannel Neuroprosthesis for Bladder Control After Spinal Cord Injury in Rat
Authors: Chew Daniel J. , Zhu Lan , Delivopoulos Evangelos , Minev Ivan R. , Musick Katherine M. , Mosse Charles A. , Craggs Michael , Donaldson Nicholas , Lacour Stéphanie P. , McMahon Stephen B. , Fawcett James W.
Published: November 2013

An electronic interface for recording and stimulating nerves that innervate the bladder helps to restore normal bladder function in rats with spinal cord injury.
Money for Robots
Authors: LaMarco Kelly
Published: November 2013

Co-robots might be our new best friends if a U.S. federal funding initiative is successful.
Factors Affecting the Initial Adhesion and Retention of the Plant Pathogen Xylella fastidiosa in the Foregut of an Insect Vector
Authors: Killiny Nabil , Almeida Rodrigo P. P.
Published: November 2013

Vector transmission of bacterial plant pathogens involves three steps: pathogen acquisition from an infected host, retention within the vector, and inoculation of cells into susceptible tissue of an uninfected plant. In this study, a combination of plant and artificial diet systems were used to determine the importance of several genes on the initial adhesion and retention of the bacterium
Xylella fastidiosa
to an efficient insect vector. Mutant strains included fimbrial (
fimA
and
pilB
) and afimbrial (
hxfA
and
hxfB
) adhesins and three loci involved in regulatory systems (
rpfF
,
rpfC
, and
cgsA
). Transmission assays with variable retention time indicated that HxfA and HxfB were primarily important for early adhesion to vectors, while FimA was necessary for both adhesion and retention. The long pilus protein PilB was not deficient in initial adhesion but may be important for retention. Genes upregulated under the control of
rpfF
are important for both initial adhesion and retention, as transmission rates of this mutant strain were initially low and decreased over time, while disruption of
rpfC
and
cgsA
yielded trends similar to that shown by the wild-type control. Because induction of an
X. fastidiosa
transmissible state requires pectin, a series of experiments were used to test the roles of a polygalacturonase (
pglA
) and the pectin and galacturonic acid carbohydrates on the transmission of
X. fastidiosa
. Results show that galacturonic acid, or PglA activity breaking pectin into its major subunit (galacturonic acid), is required for
X. fastidiosa
vector transmission using an artificial diet system. This study shows that early adhesion and retention of
X. fastidiosa
are mediated by different factors. It also illustrates that the interpretation of results of vector transmission experiments, in the context of vector-pathogen interaction studies, is highly dependent on experimental design.
Role of the Trypanosoma brucei HEN1 Family Methyltransferase in Small Interfering RNA Modification
Authors: Shi Huafang , Barnes Rebecca L. , Carriero Nicholas , Atayde Vanessa D. , Tschudi Christian , Ullu Elisabetta
Published: November 2013

Parasitic protozoa of the flagellate order Kinetoplastida represent one of the deepest branches of the eukaryotic tree. Among this group of organisms, the mechanism of RNA interference (RNAi) has been investigated in
Trypanosoma brucei
and to a lesser degree in
Leishmania
(
Viannia
) spp. The pathway is triggered by long double-stranded RNA (dsRNA) and in
T. brucei
requires a set of five core genes, including a single Argonaute (AGO) protein,
T. brucei
AGO1 (
Tb
AGO1). The five genes are conserved in
Leishmania
(
Viannia
) spp. but are absent in other major kinetoplastid species, such as
Trypanosoma cruzi
and
Leishmania major
. In
T. brucei
small interfering RNAs (siRNAs) are methylated at the 3′ end, whereas
Leishmania
(
Viannia
) sp. siRNAs are not. Here we report that
T. brucei
HEN1, an ortholog of the metazoan HEN1 2′-
O
-methyltransferases, is required for methylation of siRNAs. Loss of
Tb
HEN1 causes a reduction in the length of siRNAs. The shorter siRNAs in
hen1
−/−
parasites are single stranded and associated with
Tb
AGO1, and a subset carry a nontemplated uridine at the 3′ end. These findings support a model wherein
Tb
HEN1 methylates siRNA 3′ ends after they are loaded into
Tb
AGO1 and this methylation protects siRNAs from uridylation and 3′ trimming. Moreover, expression of
Tb
HEN1 in
Leishmania
(
Viannia
)
panamensis
did not result in siRNA 3′ end methylation, further emphasizing mechanistic differences in the trypanosome and
Leishmania
RNAi mechanisms.
Imaging Early Pathogenesis of Bubonic Plague: Are Neutrophils Commandeered for Lymphatic Transport of Bacteria?
Authors: Bland David M. , Anderson Deborah M.
Published: November 2013

Vector-borne infections begin in the dermis when a pathogen is introduced by an arthropod during a blood meal. Several barriers separate an invading pathogen from its replicative niche, including phagocytic cells in the dermis that activate immunity by engulfing would-be pathogens and migrating to the lymph node. In addition, neutrophils circulating in the blood are rapidly recruited when the dermal barriers are penetrated. For flea-borne disease, no insect-encoded immune-suppressive molecules have yet been described that might influence the establishment of infection, leaving the bacteria on their own to defend against the mammalian immune system. Shortly after a flea transmits
Yersinia pestis
to a mammalian host, the bacteria are transported to the lymph node, where they grow logarithmically and later spread systemically. Even a single cell of
Y. pestis
can initiate a lethal case of plague. In their article, J. G. Shannon et al. [mBio 4(5):e00170-13, 2013, doi:10.1128/mBio.00170-13] used intravital microscopy to visualize trafficking of
Y. pestis
in transgenic mice
in vivo
, which allowed them to examine interactions between bacteria and specific immune cells. Bacteria appeared to preferentially interact with neutrophils but had no detectable interactions with dendritic cells. These findings suggest that
Y. pestis
infection of neutrophils not only prevents their activation but may even result in their return to circulation and migration to distal sites.
Wild blueberry consumption affects aortic vascular function in the obese Zucker rat
Authors: Vendrame Stefano , Kristo Aleksandra S. , Schuschke Dale A. , Klimis-Zacas Dorothy
Published: November 2013

This study evaluates the effect of wild blueberry (WB) consumption on the biomechanical properties of the aorta in the obese Zucker rat (OZR), a model of the metabolic syndrome. Thirty-six OZRs and 36 lean controls (lean Zucker rats) were placed either on a WB-enriched or a control (C) diet for 8 weeks. Phenylephrine (Phe)-mediated vasoconstriction and acetylcholine (Ach)-mediated vasorelaxation in the aortic vessel were investigated, as well as the contribution of the nitric oxide synthase and cyclooxygenase (COX) pathways in each of the above responses by using specific inhibitors. Obese Zucker rats exhibited a reduced vasocontstrictor response to Phe and an exaggerated vasorelaxant response to Ach. The WB diet partially restored Phe-induced constrictor responses and attenuated Ach-induced relaxant responses in OZR. Plasma nitric oxide was significantly attenuated (22.1 ± 1.1 μmol·L−1, WB vs 25.6 ± 1.4 μmol·L−1, C, p ≤ 0.05) with the WB diet. Thromboxane A2 levels in the aortic effluent were not significantly affected in the WB diet group, while PGI2 concentration significantly increased (766.5 ± 92.2 pg·mg−1 aorta in the WB vs 571.7 ± 37.8 pg·g−1 aorta in the C group, p ≤ 0.05). Downregulation of inducible nitric oxide synthase and COX2 expression in the OZR aorta was observed in the WB diet group. In conclusion, WB consumption altered the biomechanical properties of the OZR aorta by partially restoring the impaired Phe-induced constrictor responses and attenuating the exaggerated response to Ach-induced vasorelaxation.
Effects of initial coherence on distinguishability of pure/mixed states and chiral stability in an open chiral system
Authors: Han Heekyung , Wardlaw David M. , Frolov Alexei M.
Published: November 2013

We examine how initial coherences in open chiral systems affect distinguishability of pure versus mixed states and purity decay. Interaction between a system and an environment is modeled by a continuous position measurement and a two-level approximation is taken for the system. The resultant analytical solution is explored for various parameters, with emphasis on the interplay of initial coherences of the system and dephasing rate in determining the purity decay and differences in the time evolution of pure versus mixed initial states. Implications of the results for several fundamental problems are noted.
On the strength and nature of intermolecular X···O interactions in CF2ClBr−O3complexes (X = F, Cl, Br): an ab initio investigation
Authors: Esrafili Mehdi D. , Solimannejad Mohammad
Published: November 2013

Ab initio calculations were realized to analyze the existence of intermolecular X···O interactions in bromochlorodifluoromethane (CF2ClBr) complexes with ozone, where X = F, Cl, and Br. These calculations have been carried out using MP2 and CCSD(T) methods, through analysis of surface electrostatic potentials V(r), intermolecular interaction energies, and electron density analysis. Coupled cluster (CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ) calculations indicate that the stabilization energies for the CF2ClBr−O3complexes lie in the range between –3.9 and –7.7 kJ/mol. The characteristic of X···O interactions has been identified in terms of the electron density analysis within the quantum theory of atoms in molecules. Energy decomposition analysis shows that the attractive nature of the X···O interactions within the title complexes is chiefly due to dispersion effects, but electrostatic contribution also plays an important role.
Using coherent control to extract the phases of electronic transition-dipole matrices: the LiRb case
Authors: Menzel-Jones Cian , Shapiro Moshe
Published: November 2013

We show that “bichromatic coherent control” (BCC) enables the determination of the amplitudes (= magnitudes + phases) of individual transition-dipole matrix elements (TDMs) and the amplitude of time-evolving wave packets from time-resolved fluorescence data. In the present use of BCC, one induces quantum interferences using two external laser fields to coherently deplete the population of different pairs of excited energy eigenstates. The BCC-induced depletion is supplemented by the computation of the Fourier integral of the time-resolved fluorescence at the beat frequencies of the two states involved. The combination of BCC and Fourier transform enables the determination of both the expansion coefficients of the wave packet in a basis of vibrational energy eigenstates and the amplitudes of the [Formula: see text] electronic TDMs linking the excited and ground rovibrational states. We illustrate our method by determining the amplitudes of the TDMs linking the vibrational states of the [Formula: see text] spin orbit coupled potentials to both the singlet [Formula: see text] and the triplet [Formula: see text] electronic ground states in LiRb. The approach, which is found to be quite robust against errors in the BCC procedure and experimental data, can be readily generalized to the imaging of wave packets of polyatomic molecules.
SIMULATING TOPOLOGICAL EFFECTS WITH PHOTONS IN COUPLED QED CAVITY ARRAYS
Authors: NOH CHANGSUK , ANGELAKIS DIMITRIS G.
Published: November 2013

We provide a pedagogical account of an early proposal realizing fractional quantum Hall effect (FQHE) using coupled quantum electrodynamics (QED) cavity arrays (CQCAs). We start with a brief introduction on the basics of quantum Hall effects and then review the early proposals in the simulation of spin-models and fractional quantum Hall (FQH) physics with photons in coupled atom-cavity arrays. We calculate the energy gap and the overlap between the ground state of the system and the corresponding Laughlin wavefunction to analyze the FQH physics arising in the system and discuss possibilities to reach the ground state using adiabatic methods used in Cavity QED.
Hardware/software approaches for reducing the process variation impact on instruction fetches
Authors: Kadayif Ismail , Turkcan Mahir , Kiziltepe Seher , Ozturk Ozcan
Published: November 2013

As technology moves towards finer process geometries, it is becoming extremely difficult to control critical physical parameters such as channel length, gate oxide thickness, and dopant ion concentration. Variations in these parameters lead to dramatic variations in access latencies in Static Random Access Memory (SRAM) devices. This means that different lines of the same cache may have different access latencies. A simple solution to this problem is to adopt the worst-case latency paradigm. While this egalitarian cache management is simple, it may introduce significant performance overhead during instruction fetches when both address translation (instruction Translation Lookaside Buffer (TLB) access) and instruction cache access take place, making this solution infeasible for future high-performance processors. In this study, we first propose some hardware and software enhancements and then, based on those, investigate several techniques to mitigate the effect of process variation on the instruction fetch pipeline stage in modern processors. For address translation, we study an approach that performs the virtual-to-physical page translation once, then stores it in a special register, reusing it as long as the execution remains on the same instruction page. To handle varying access latencies across different instruction cache lines, we annotate the cache access latency of instructions within themselves to give the circuitry a hint about how long to wait for the next instruction to become available.