bluuebunny/crossref_metadata_2025 huggingface dataset:
Single channel surface electromyography blind recognition model based on watermarking
Authors: Yina Guo , Dawei Zhou
Published: May 2011

A single channel electromyography blind recognition model based on watermarking is proposed in this paper. Single Channel Independent Component Analysis is adopted to avoid complicated circuit connection and the unreliability of hardware and reduce the noise which accompanied with surface Electromyography (sEMG) signals. Embedded watermarking is applied to solve the problem of blind source separation disorder. A self adaptive neural network and some eigenvectors are applied in sEMG features classification. From the classification results, hand gestures can be recognized. In consideration of time-scale synchronization attack, the host sEMG signals are transformed into wavelet domain and the synchronization codes are embedded. The experiment results show that the model proposed in this paper is penetrable against most common signal processing, and can recognize the hand gesture accurately.
Experimental validation of a shape memory alloy retrofitting application
Authors: AlSaleh R , Casciati F , El-Attar A , El-Habbal I
Published: May 2011

Minarets are spread across urban nuclei. Their structural weakness could result in failures with heavy consequences. However, the retrofit solutions are limited due to their simple cantilever scheme. The use of metallic pre-stressed wires/cables is a rather consolidated technique. The use of shape memory alloy (SMA) wires has been recently investigated. In view of such an application, a series of reduced-scale tests was planned and realized. This paper synthesizes the full report on an experimental work performed to study the effect of SMA wires on the dynamic behavior of a single degree of freedom model built in laboratory to represent a 1/16th of a minaret actually built in Cairo, Egypt. The model was tested under free vibration for different values of the axial force, before and after adding SMA wires. The results showed enhancements in the stiffness when the SMA wires were added and when the axial force increased, while a decrease in damping ratios was detected when increasing the applied axial force or after providing SMA wires.
Improved low-frequency performance of a composite sound absorption coating
Authors: Meng Tao , Hong-Xing Hua
Published: May 2011

In order to improve the low-frequency acoustic performance, a composite sound absorption coating made by embedding another viscoelastic material into the viscoelastic substrate of the traditional sound absorption coating, has been developed. Compared to the substrate, the transverse wave speed of the embedded-layer is lower. Accounting for the symmetry, the unit cell of the traditional sound absorption coating or the composite sound absorption coating could be approximately regarded as a viscoelastic single-layer cylindrical tube or a viscoelastic double-layer cylindrical tube, respectively. The plane wave normally impinging on the sound absorption coating only excites the axisymmetric wave propagating in the axial direction of the viscoelastic cylindrical tube. If the complex axisymmetric wave number and the effective impedance of the viscoelastic cylindrical tube are obtained, the acoustic performance of the sound absorption coating could be evaluated by using the transfer matrix method, which is suitable for both the single-layer cylindrical tube and the double-layer cylindrical tube. Numerical results show that the peak frequency of the sound absorption coefficient is shifted to the lower location as the proportion of the embedded-layer increases, or the transverse wave speed of the embedded-layer decreases.
Comparative cost-efficiency across the European G5 countries of various regimens of filgrastim, biosimilar filgrastim, and pegfilgrastim to reduce the incidence of chemotherapy-induced febrile neutropenia
Authors: Aapro Matti , Cornes Paul , Abraham Ivo
Published: May 2011

Objectives: This cost-efficiency analysis of the granulocyte colony-stimulating factors (G-CSF) filgrastim (originator Neupogen® and biosimilar Zarzio®) and pegfilgrastim (Neulasta®) examined against a time horizon of 1–14 days of treatment and across the European Union G5 countries (a) when, cost-wise, using Neulasta® 6 mg versus Neupogen® or Zarzio® 300 µg may be cost-saving in reducing the incidence of chemotherapy-induced febrile neutropenia; and (b) if cost-wise, treatment with Zarzio® 300 µg yields a savings advantage over Neupogen® 300 µg.

Methods: Cost-efficiency analysis of the direct costs a buyer or payer would incur when purchasing or covering any of these agents for managing one patient during one cycle of chemotherapy under regimens of 1–14 days of standard filgrastim using the population-weighted average unit dose cost of each agent per their public pack cost across the European G5 countries.

Results: The cost of Neupogen® treatment ranged from €128.16 (1 day) to €1794.30 (14 days), compared to €95.46 and €1336.46 for Zarzio®, thus yielding potential cost savings from €32.70 to €457.84 for the latter. Neulasta® turns cost-saving at day 12 of Neupogen® treatment. At no point over a 14-day treatment period did Neulasta® yield a savings advantage over Zarzio®.

Conclusion: Prophylaxis or treatment of febrile neutropenia with Zarzio® is cost-efficient under all possible treatment scenarios relative to Neupogen® and to Neulasta®. In the absence of convincing evidence that pegfilgrastim is pharmacotherapeutically superior to standard filgrastim, there is no cost-efficiency rationale to treat with Neulasta® over Zarzio®, though there may be a small window of approximately 3 days where Neulasta® is cost-efficient over Neupogen®. Regardless, our analysis shows Zarzio® to be the most cost-efficient approach to reducing the incidence of febrile neutropenia in chemotherapy-treated patients.
Play at work: continuation, intervention and usurpation
Authors: Sørensen Bent Meier , Spoelstra Sverre
Published: May 2011

The interest in organizational play is growing, both in popular business discourse and organization studies. As the presumption that play is dysfunctional for organizations is increasingly discarded, the existing positions may be divided into two camps; one proposes ‘serious play’ as an engine for business and the other insists that work and play are largely indistinguishable in the postindustrial organization. Our field study of a design and communications company in Denmark shows that organizational play can be much more than just functional to the organization. We identify three ways in which workplaces engage in play: play as a (serious) continuation of work, play as a (critical) intervention into work and play as an (uninvited) usurpation of work.
Self-determination and Exercise Stages of Change: Results from the Diabetes Aerobic and Resistance Exercise Trial
Authors: Fortier Michelle S. , Sweet Shane N. , Tulloch Heather , Blanchard Chris M. , Sigal Ronald J. , Kenny Glen P. , Reid Robert D.
Published: May 2011

Little longitudinal research exists on the relationship between exercise self-determination and stage of change. This study investigated how self-determined motivation changes in patients with type 2 diabetes ( N = 175) as they moved through the stages of change over a six-month exercise trial. Hierarchical linear modelling revealed that patients who progressed through the stages of exercise change had an overall increase in self-determined motivation, while non-progressors experienced a reduction in self-determined motivation from three to six months. These results indicate that individuals engaging in regular exercise at six months maintain initial increases in self-determined motivation. Findings are discussed in light of self-determination theory.
College students on the autism spectrum
Authors: White Susan W. , Ollendick Thomas H. , Bray Bethany C.
Published: May 2011

As more young people are identified with autism spectrum diagnoses without co-occurring intellectual disability (i.e. high-functioning autism spectrum disorder; HFASD), it is imperative that we begin to study the needs of this population. We sought to gain a preliminary estimate of the scope of the problem and to examine psychiatric risks associated HFASD symptoms in university students. In a large sample ( n = 667), we examined prevalence of ASD in students at a single university both diagnostically and dimensionally, and surveyed students on other behavioral and psychiatric problems. Dependent upon the ascertainment method, between .7 per cent and 1.9 per cent of college students could meet criteria for HFASD. Of special interest, none of the students who were found to meet diagnostic criteria ( n = 5) formally for HFASD in this study had been previously diagnosed. From a dimensional perspective, those students scoring above the clinical threshold for symptoms of autism ( n = 13) self-reported more problems with social anxiety than a matched comparison group of students with lower autism severity scores. In addition, symptoms of HFASD were significantly correlated with symptoms of social anxiety, as well as depression and aggression. Findings demonstrate the importance of screening for autism-related impairment among university students.
Evaluation of the revised algorithm of Autism Diagnostic Observation Schedule (ADOS) in the diagnostic investigation of high-functioning children and adolescents with autism spectrum disorders
Authors: Kamp-Becker Inge , Ghahreman Mardjan , Heinzel-Gutenbrunner Monika , Peters Mira , Remschmidt Helmut , Becker Katja
Published: May 2011

The Autism Diagnostic Observation Schedule (ADOS) is a semi-structured, standardized assessment designed for use in diagnostic evaluation of individuals with suspected autism spectrum disorder (ASD). The ADOS has been effective in categorizing children who definitely have autism or not, but has lower specificity and sometimes sensitivity for distinguishing children with milder ASDs. Revised ADOS algorithms have been recently developed. The goals of this study were to analyze the predictive validity of different ADOS algorithms for module 3, in particular for high-functioning autism spectrum disorder. The participants were 252 children and adolescents aged between four and 16 years, with a full-scale IQ above 70 (126 with a diagnosis of ASD, 126 with a heterogeneous non-spectrum diagnosis). As a main finding, sensitivity was substantially higher for the newly developed ‘revised algorithm’, both for autism versus non-spectrum, as well as for the broader ASD versus non-spectrum, using the higher cut-off. The strength of the original algorithm lies in its positive predictive power, while the revised algorithm shows weaknesses in specificity for non-autism ASD. As the ADOS is valid and reliable even for higher functioning ASD, the findings of the present study have been used to make recommendations regarding the best use of ADOS algorithms in a high-functioning sample.
The Effect of Balconies on Ventilation Performance of Low-rise Buildings
Authors: Ai Z.T. , Mak C.M. , Niu J.L. , Li Z.R. , Zhou Q.
Published: May 2011

Chand et al. conducted experiments in a low speed wind tunnel to study the effect of balconies on the ventilative force on low-rise buildings without openings. Using their model, this study intends to investigate indoor ventilation performance by examining mass flow rate and average velocity on the working plane using computational fluid dynamics. Simulations were validated against their experiments. The numerical results indicate that, for single-sided ventilation, the provision of balconies increases mass flow rate and reduces average velocity on the working plane in most rooms, but for cross ventilation, this provision has no significant effect under normally or obliquely incident wind conditions. After the addition of balconies, the worst ventilation circumstances on the windward side under single-sided ventilation conditions were found on the intermediate floor. The simulation results also showed that, in many cases, wind flows into and out of the rooms through the left or right side of the opening rather than through the bottom and top of the opening, especially in the case of buildings that are obliquely oriented to the air stream. This phenomenon demonstrates that predictions of single-sided ventilative force using data relating to the bottom and top parts of the opening are not accurate enough.
Study of the effect of the spiral geometry on wheel/rail contact forces
Authors: Shabana A A , El-Ghandour A I , Zaazaa K E
Published: May 2011

Spiral sections are used in the construction of railroad tracks in order to achieve a smooth change in the curvature. In order to satisfy the kinematic conditions at the position, velocity, and acceleration levels in railroad vehicle dynamics computational algorithms based on the constraint contact formulations; third-order derivatives of the wheel/rail contact constraint functions with respect to the wheel and rail geometric surface parameters must be evaluated. Discontinuities in these higher derivatives can produce jumps in the wheel/rail contact forces at the spiral entries and exits. This paper develops a simple procedure that can be applied online to ensure that the curvature and its derivative of the rail space curve are continuous at the spiral entries and exits. Because continuity of the space curve geometric variables does not ensure continuity of these variables on the rail surface, the effect of the proposed procedure on the contact forces is examined. The constraint and elastic wheel/rail contact formulations are first reviewed in order to show the degree of continuity required and the basic kinematic conditions used to search online for the wheel/rail contact points. The rigid track geometry is described using the absolute nodal coordinate formulation (ANCF), which employs a geometric description that ensures the continuity of the position and gradient vectors at the track nodes. In order to ensure the continuity of the curvature vector and its derivative at the intersection of the spirals with the tangent and curve segments, a set of linear conditions are developed and solved online, allowing for implicit elimination of track nodal variables. These conditions are not considered as kinematic constraints imposed on the system motion since they are mainly used to improve the rigid track geometric description and do not involve the system generalized coordinates or their time derivatives. The procedure described in this investigation does not require making changes in the description of the track geometry and does not require the use of higher order derivatives of the track node angles in order to achieve the desired degree of continuity. Because higher degree of continuity achieved for the rail space curve does not ensure a similar degree of continuity on the surface where the wheel/rail contact occurs; the effect of the change of the degree of continuity of the space curve at the spiral entries and exits on the rail surface geometry is also discussed in this paper. The results presented in this study show that the proposed procedure can lead to improvement in the wheel/rail contact force results in some simulation scenarios. The results, obtained using the proposed procedure, are compared with the results obtained using local mesh refinements.
Neurological Principles and Rehabilitation of Action Disorders
Authors: Frey Scott H. , Fogassi Leonardo , Grafton Scott , Picard Nathalie , Rothwell John C. , Schweighofer Nicolas , Corbetta Maurizio , Fitzpatrick Susan M.
Published: May 2011

This chapter outlines the basic computational, anatomical, and physiological (CAP) principles underlying upper-limb actions, such as reaching for a cup and grasping it or picking up a key, inserting it into a lock, and turning it.
Mechanics performance of three-degree-of-freedom excavating mechanism of an electric shovel
Authors: Wei B , Gao F , Chen J , He J , Wu S , Song Q
Published: May 2011

Electric shovel is one of the most important equipment in surface-mining operations. The medium–tool interaction model is an essential basis in the process of machine design. Therefore, it is important to make the model accurate compared to the actual situation. This article proposes a new medium–tool interaction model based on the analysis of medium–tool interaction mechanism taking into account the actual excavating process. The result of the new model is quite in agreement with the full-scale tests. In order to make the excavating process more efficient, the traditional two-degree-of-freedom (DOF) excavating mechanism is redesigned and a new three-DOF excavating mechanism is obtained. A new electric shovel with three-DOF excavating mechanism is more flexible in that it will perform the excavation process with a favourable excavating angle that can reduce the resistance force involved in medium–tool interaction. Based on the new medium–tool interaction model, the dynamic model of the three-DOF excavating mechanism is established for the mechanics performance analysis. The numeric validation shows that the new excavating mechanism is more efficient in the excavating process.
An Investigation of Nurses' Knowledge, Attitudes, and Practices Regarding Disinfection Procedures in Italy
Authors: Sessa Alessandra , Di Giuseppe Gabriella , Albano Luciana , Angelillo Italo F ,   the Collaborative Working Group
Published: May 2011

Background

This study assessed the level of knowledge, attitudes, and practice regarding disinfection procedures among nurses in Italian hospitals.

Methods

A face-to-face interview gathered the following information: demographic and practice characteristics; knowledge about the healthcare-associated infections (HAIs) and the disinfection practices; attitudes towards the utility of guidelines/protocols and perception of the risks of acquiring/transmitting HAIs; compliance with antisepsis/disinfection procedures; and sources of information.

Results

Only 29% acknowledged that urinary and respiratory tract infections were the two most common HAIs and this knowledge was significantly higher in those with a higher level of education. Attitudes towards the utility of guidelines/protocols for disinfection procedures showed a mean score of 9.1. The results of the linear regression model indicated a more positive attitude in female nurses, in those with a lower number of years of activity, and in those needing additional information about disinfection procedures. Nurses with higher educational level and with a higher perception of risk of transmitting an infectious disease while working were more likely to perform appropriate antisepsis of the surgical wound and handwashing before and after medication.

Conclusions

Plan of successful prevention activities about HAIs and provide pointers to help optimize disinfection procedures and infection prophylaxis and management are needed.
Fibromyalgia and neuropathic pain - differences and similarities. A comparison of 3057 patients with diabetic painful neuropathy and fibromyalgia
Authors: Koroschetz Jana , Rehm Stefanie E , Gockel Ulrich , Brosz Mathias , Freynhagen Rainer , Tölle Thomas R , Baron Ralf
Published: May 2011

Background

Patients with diabetic neuropathy (DPN) and fibromyalgia differ substantially in pathogenetic factors and the spatial distribution of the perceived pain. We questioned whether, despite these obvious differences, similar abnormal sensory complaints and pain qualities exist in both entities. We hypothesized that similar sensory symptoms might be associated with similar mechanisms of pain generation. The aims were (1) to compare epidemiological features and co-morbidities and (2) to identify similarities and differences of sensory symptoms in both entities.

Methods

The present multi-center study compares epidemiological data and sensory symptoms of a large cohort of 1434 fibromyalgia patients and 1623 patients with painful diabetic neuropathy. Data acquisition included standard demographic questions and self-report questionnaires (MOS sleep scale, PHQ-9, PainDETECT). To identify subgroups of patients with characteristic combinations of symptoms (sensory profiles) a cluster analysis was performed using all patients in both cohorts.

Results

Significant differences in co-morbidities (depression, sleep disturbance) were found between both disorders. Patients of both aetiologies chose very similar descriptors to characterize their sensory perceptions. Burning pain, prickling and touch-evoked allodynia were present in the same frequency. Five subgroups with distinct symptom profiles could be detected. Two of the subgroups were characteristic for fibromyalgia whereas one profile occurred predominantly in DPN patients. Two profiles were found frequently in patients of both entities (20-35%).

Conclusions

DPN and fibromyalgia patients experience very similar sensory phenomena. The combination of sensory symptoms - the sensory profile - is in most cases distinct and almost unique for each one of the two entities indicating aetiology-specific mechanisms of symptom generation. Beside the unique aetiology-specific sensory profiles an overlap of sensory profiles can be found in 20-35% of patients of both aetiologies.
The natural history of West Nile virus infection presenting with West Nile virus meningoencephalitis in a man with a prolonged illness: a case report
Authors: Mainali Shraddha , Afshani Mansoor , Wood James B , Levin Michael C
Published: May 2011

Introduction

Estimates indicate that West Nile virus infects approximately one and a half million people in the United States of America. Up to 1% may develop West Nile virus neuroinvasive disease, in which infected patients develop any combination of meningitis, encephalitis, or acute paralysis.

Case presentation

A 56-year-old African-American man presented to our hospital with headache, restlessness, fever, myalgias, decreased appetite, and progressive confusion. A cerebrospinal fluid examination showed mild leukocytosis and an elevated protein level. Testing for routine infections was negative. Brain T2-weighted magnetic resonance imaging scans showed marked enlargement of caudate nuclei and increased intensity within the basal ganglia and thalami. A West Nile virus titer was positive, and serial brain magnetic resonance imaging scans showed resolving abnormalities that paralleled his neurological examination.

Conclusion

This report is unusual as it portrays the natural history and long-term consequences of West Nile virus meningoencephalitis diagnosed on the basis of serial brain images.
Endotoxin-induced uveitis is primarily dependent on radiation-resistant cells and on MyD88 but not TRIF
Authors: Kezic J , Taylor S , Gupta S , Planck S R , Rosenzweig H L , Rosenbaum J T
Published: May 2011

TLR4 activation by LPS (endotoxin) is mediated by the MyD88 and TRIF intracellular signaling pathways. We determined the relative activation of these pathways in murine ocular tissue after LPS exposure. Additionally, we explored whether BM-derived or non-BM-derived cells were the major contributors to EIU. Mice deficient in TRIF or MyD88 and their congenic (WT) controls received 250 ng ultrapure LPS ivt at 0 h. Ocular inflammation was assessed by histological analysis at 4, 6, and 24 h, and additionally, in MyD88−/− mice, intravital microscopy was performed at 4 h and 6 h to assess adherent, rolling, and infiltrating cells in the iris vasculature and tissue. Cytokines associated with the MyD88 and TRIF intracellular signaling pathways were analyzed in ocular tissue at 4 h. BM chimeric mice (WT→WT, TLR4−/−→WT, WT→TLR4−/−) received 250 ng LPS by ivt injection, and ocular tissues were examined by histology at 6 h. Lack of MyD88 resulted in a markedly diminished cellular response and reduced production of MyD88-related cytokines 4 h post-LPS treatment. In contrast, lack of TRIF led to reduced production of TRIF-related cytokines and no change in the cellular response to LPS. Therefore, the MyD88 pathway appears to be the dominant TLR4 pathway in EIU. Only WT → TLR4−/− chimeric mice were resistant to EIU, and this suggests, surprisingly, that non-BM-derived (radiation-resistant) cells in the eye play a greater role than BM-derived cells.
Steroidogenic Factor-1 (SF-1)-Driven Differentiation of Murine Embryonic Stem (ES) Cells into a Gonadal Lineage
Authors: Jadhav Unmesh , Jameson J. Larry
Published: May 2011

Steroidogenic factor 1 (SF-1) is essential for the development and function of steroidogenic tissues. Stable incorporation of SF-1 into embryonic stem cells (SF-1-ES cells) has been shown to prime the cells for steroidogenesis. When provided with exogenous cholesterol substrate, and after treatment with retinoic acid and cAMP, SF-1-ES cells produce progesterone but do not produce other steroids such as cortisol, estradiol, or testosterone. In this study, we explored culture conditions that optimize SF-1-mediated differentiation of ES cells into defined steroidogenic lineages. When embryoid body formation was used to facilitate cell lineage differentiation, SF-1-ES cells were found to be restricted in their differentiation, with fewer cells entering neuronal pathways and a larger fraction entering the steroidogenic lineage. Among the differentiation protocols tested, leukemia inhibitory factor (LIF) removal, followed by prolonged cAMP treatment was most efficacious for inducing steroidogenesis in SF-1-ES cells. In this protocol, a subset of SF-1-ES cells survives after LIF withdrawal, undergoes morphologic differentiation, and recovers proliferative capacity. These cells are characterized by induction of steroidogenic enzyme genes, use of de novo cholesterol, and production of multiple steroids including estradiol and testosterone. Microarray studies identified additional pathways associated with SF-1 mediated differentiation. Using biotinylated SF-1 in chromatin immunoprecipitation assays, SF-1 was shown to bind directly to multiple target genes, with induction of binding to some targets after steroidogenic treatment. These studies indicate that SF-1 expression, followed by LIF removal and treatment with cAMP drives ES cells into a steroidogenic pathway characteristic of gonadal steroid-producing cells.
A novel chemically directed route for the generation of definitive endoderm from human embryonic stem cells based on inhibition of GSK-3
Authors: Bone Heather K. , Nelson Adam S. , Goldring Christopher E. , Tosh David , Welham Melanie J.
Published: May 2011

The use of small molecules to ‘chemically direct’ differentiation represents a powerful approach to promote specification of embryonic stem cells (ESCs) towards particular functional cell types for use in regenerative medicine and pharmaceutical applications. Here, we demonstrate a novel route for chemically directed differentiation of human ESCs (hESCs) into definitive endoderm (DE) exploiting a selective small-molecule inhibitor of glycogen synthase kinase 3 (GSK-3). This GSK-3 inhibitor, termed 1m, when used as the only supplement to a chemically defined feeder-free culture system, effectively promoted differentiation of ESC lines towards primitive streak (PS), mesoderm and DE. This contrasts with the role of GSK-3 in murine ESCs, where GSK-3 inhibition promotes pluripotency. Interestingly, 1m-mediated induction of differentiation involved transient NODAL expression and Nodal signalling. Prolonged treatment of hESCs with 1m resulted in the generation of a population of cells displaying hepatoblast characteristics, that is expressing α-fetoprotein and HNF4α. Furthermore, 1m-induced DE had the capacity to mature and generate hepatocyte-like cells capable of producing albumin. These findings describe, for the first time, the utility of GSK-3 inhibition, in a chemically directed approach, to a method of DE generation that is robust, potentially scalable and applicable to different hESC lines.
Stargazin-related protein γ7 is associated with signalling endosomes in superior cervical ganglion neurons and modulates neurite outgrowth
Authors: Waithe Dominic , Ferron Laurent , Dolphin Annette C.
Published: May 2011

The role(s) of the newly discovered stargazin-like γ-subunit proteins remains unclear; although they are now widely accepted to be transmembrane AMPA receptor regulatory proteins (TARPs), rather than Ca2+ channel subunits, it is possible that they have more general roles in trafficking within neurons. We previously found that γ7 subunit is associated with vesicles when it is expressed in neurons and other cells. Here, we show that γ7 is present mainly in retrogradely transported organelles in sympathetic neurons, where it colocalises with TrkA–YFP, and with the early endosome marker EEA1, suggesting that γ7 localises to signalling endosomes. It was not found to colocalise with markers of the endoplasmic reticulum, mitochondria, lysosomes or late endosomes. Furthermore, knockdown of endogenous γ7 by short hairpin RNA transfection into sympathetic neurons reduced neurite outgrowth. The same was true in the PC12 neuronal cell line, where neurite outgrowth was restored by overexpression of human γ7. These findings open the possibility that γ7 has an essential trafficking role in relation to neurite outgrowth as a component of endosomes involved in neurite extension and growth cone remodelling.
Kinematics of the quadrate bone during feeding in mallard ducks
Authors: Dawson Megan M. , Metzger Keith A. , Baier David B. , Brainerd Elizabeth L.
Published: May 2011

Avian cranial kinesis, in which mobility of the quadrate, pterygoid and palatine bones contribute to upper bill elevation, is believed to occur in all extant birds. The most widely accepted model for upper bill elevation is that the quadrate rotates rostrally and medially towards the pterygoid, transferring force to the mobile pterygoid–palatine complex, which pushes on the upper bill. Until now, however, it has not been possible to test this hypothesis in vivo because quadrate motions are rapid, three-dimensionally complex and not visible externally. Here we use a new in vivo X-ray motion analysis technique, X-ray reconstruction of moving morphology (XROMM), to create precise (±0.06 mm) 3-D animations of the quadrate, braincase, upper bill and mandible of three mallard ducks, Anas platyrhynchos. We defined a joint coordinate system (JCS) for the quadrato-squamosal joint with the axes aligned to the anatomical planes of the skull. In this coordinate system, the quadrate's 3-D rotations produce an elliptical path of pterygoid process motion, with medial and rostrodorsal then lateral and rostrodorsal motion as the upper bill elevates. As the upper bill depresses, the pterygoid process continues along the ellipsoidal path, with lateral and caudoventral then medial and caudoventral motion. We also found that the mandibular rami bow outwards (streptognathy) during mandibular depression, which may cause the lateral component of quadrate rotation that we observed. Relative to the JCS aligned with the anatomical planes of the skull, a second JCS aligned with quadrato-squamosal joint anatomy did not produce a simpler description of quadrate kinematics.
The influence of trout cardiac troponin I and PKA phosphorylation on the Ca2+ affinity of the cardiac troponin complex
Authors: Kirkpatrick Kelly P. , Robertson Andrew S. , Klaiman Jordan M. , Gillis Todd E.
Published: May 2011

The trout heart is 10-fold more sensitive to Ca2+ than the mammalian heart. This difference is due, in part, to cardiac troponin C (cTnC) from trout having a greater Ca2+ affinity than human cTnC. To determine what other proteins are involved, we cloned cardiac troponin I (cTnI) from the trout heart and determined how it alters the Ca2+ affinity of a cTn complex containing all mammalian components (mammalian cTn). Ca2+ activation of the complex was characterized using a human cTnC mutant that contains anilinonapthalenesulfote iodoacetamide attached to Cys53. When the cTn complex containing labeled human cTnC was titrated with Ca2+, its fluorescence changed, reaching an asymptote upon saturation. Our results reveal that trout cTnI lacks the N-terminal extension found in cTnI from all other vertebrate groups. This protein domain contains two targets (Ser23 and Ser24) for protein kinase A (PKA) and protein kinase C. When these are phosphorylated, the rate of cardiomyocyte relaxation increases. When rat cTnI in the mammalian cTn complex was replaced with trout cTnI, the Ca2+ affinity was increased ∼1.8-fold. This suggests that trout cTnI contributes to the high Ca2+ sensitivity of the trout heart. Treatment of the two cTn complexes with PKA decreased the Ca2+ affinity of both complexes. However, the change for the complex containing rat cTnI was 2.2-fold that of the complex containing trout cTnI. This suggests that the phosphorylation of trout cTnI does not play as significant a role in regulating cTn function in trout.
Loading effects on jump performance in green anole lizards,Anolis carolinensis
Authors: Kuo Chi-Yun , Gillis Gary B. , Irschick Duncan J.
Published: May 2011

Locomotor performance is a crucial determinant of organismal fitness but is often impaired in certain circumstances, such as increased mass (loading) resulting from feeding or gravidity. Although the effects of loading have been studied extensively for striding locomotion, its effects on jumping are poorly understood. Jumping is a mode of locomotion that is widely used across animal taxa. It demands large amounts of power over a short time interval and, consequently, may be affected by loading to a greater extent than other modes of locomotion. We placed artificial loads equal to 30% body mass on individuals of the species Anolis carolinensis to simulate the mass gain following the consumption of a large meal. We investigated the effects of loading on jump performance (maximum jump distance and accuracy), kinematics and power output. Loading caused a significant 18% decline in maximum jump distance and a significant 10% decline in takeoff speed. In other words, the presence of the load caused the lizards to take shorter and slower jumps, whereas takeoff angle and takeoff duration were not affected. By contrast, jump accuracy was unaffected by loading, although accuracy declined when lizards jumped to farther perches. Finally, mass-specific power output did not increase significantly when lizards jumped with loads, suggesting that the ability to produce mechanical power may be a key limiting factor for maximum jump performance. Our results suggest that mass gain after a large meal can pose a significant locomotor challenge and also imply a tradeoff between fulfilling energy requirement and moving efficiently in the environment.
Dolphin hearing during echolocation: evoked potential responses in an Atlantic bottlenose dolphin (Tursiops truncatus)
Authors: Li Songhai , Nachtigall Paul E. , Breese Marlee
Published: May 2011

Auditory evoked potential (AEP) responses were recorded during echolocation in an Atlantic bottlenose dolphin (Tursiops truncatus) trained to accept suction-cup EEG electrodes and detect targets by echolocation. AEP recording was triggered by the echolocation clicks of the animal. Three targets with target strengths of –34, –28 and –22 dB were used at a target distance of 2 to 6.5 m for each target. The results demonstrated that the AEP appeared to both outgoing echolocation clicks and echoes during echolocation, with AEP complexes consisting of alternative positive and negative waves. The echo-related AEP amplitudes were obviously lower than the outgoing click-related AEP amplitudes for all the targets at the investigated target distances. However, for targets with target strengths of –22 and –28 dB, the peak-to-peak amplitudes of the echo-related AEPs were dependent on the target distances. The echo-related AEP response amplitudes increased at further target distances, demonstrating an overcompensation of echo attenuation with target distance in the echo-perception system of the dolphin biosonar. Measurement and analysis of outgoing click intensities showed that the click levels increased with target distance (R) by a factor of approximately 10 to 17.5 logR depending on target strength. The results demonstrated that a dual-component biosonar control system formed by intensity compensation behavior in both the transmission and receiving phases of a biosonar cycle exists synchronously in the dolphin biosonar system.
Arctic reindeer extend their visual range into the ultraviolet
Authors: Hogg Christopher , Neveu Magella , Stokkan Karl-Arne , Folkow Lars , Cottrill Phillippa , Douglas Ronald , Hunt David M. , Jeffery Glen
Published: May 2011

The Arctic has extreme seasonal changes in light levels and is proportionally UV-rich because of scattering of the shorter wavelengths and their reflection from snow and ice. Here we show that the cornea and lens in Arctic reindeer do not block all UV and that the retina responds electrophysiologically to these wavelengths. Both rod and cone photoreceptors respond to UV at low-intensity stimulation. Retinal RNA extraction and in vitro opsin expression show that the response to UV is not mediated by a specific UV photoreceptor mechanism. Reindeer thus extend their visual range into the short wavelengths characteristic of the winter environment and periods of extended twilight present in spring and autumn. A specific advantage of this short-wavelength vision is the use of potential information caused by differential UV reflections known to occur in both Arctic vegetation and different types of snow. UV is normally highly damaging to the retina, resulting in photoreceptor degeneration. Because such damage appears not to occur in these animals, they may have evolved retinal mechanisms protecting against extreme UV exposure present in the daylight found in the snow-covered late winter environment.
Low external environmental calcium levels prevent forgetting in Lymnaea
Authors: Knezevic Bogdan , Dalesman Sarah , Karnik Vikram , Byzitter Jovita , Lukowiak Ken
Published: May 2011

Forgetting may allow an animal to react more appropriately to current conditions, rather than continuing to exhibit a previously learned, possibly maladaptive behaviour based on previous experience. One theory is that forgetting is an active process, whereby the previously learnt response is replaced by new learning that interferes with the older memory. Hence, we hypothesized that an appropriately timed environmental stressor that blocks long-term memory (LTM) formation would also block forgetting. Lymnaea stagnalis (L.) is a freshwater snail, which requires environmental calcium of at least 20 mg l–1 to meet its requirements. Low environmental Ca2+ (i.e. 20 mg l–1) in their environment acts as a stressor, and prevents LTM formation. Here, we asked whether a low Ca2+ environment would also prevent forgetting, concordant with the retrograde interference model of Jenkins and Dallenbach. Snails were operantly conditioned to reduce aerial respiration in hypoxia. When maintained in standard conditions (80 mg l–1 Ca2+), snails demonstrated LTM following training lasting 24 h, but not 72 h; however, when trained in standard conditions then exposed to a low Ca2+ environment (20 mg l–1) immediately following training, they retained memory for at least 96 h, indicating that forgetting had been blocked. Thus, when exposed to low environmental Ca2+, Lymnaea will fail to form new memories, but will also continue to retain information previously learned and remembered as the low calcium blocks forgetting.
Layer-by-layer Deposition of Ionomers with Lipophilic Ion-pairs Dissociated in Less-polar Media
Authors: Ohta Masahiko , Ono Toshikazu , Sada Kazuki
Published: May 2011

Two kinds of oppositely charged polystyrene ionomers bearing the bulky and lipophilic phosphazenium cation or diborateimidazolide anion that are soluble and dissociated partially into ions even in nonpolar solvents were prepared. Alternate complexes of them were fabricated in less-polar solvent, acetone, layer-by-layer onto a gold substrate and silica nanoparticles.
Structural and functional analysis of Nro1/Ett1: a protein involved in translation termination in S. cerevisiae and in O2-mediated gene control in S. pombe
Authors: Rispal Delphine , Henri Julien , van Tilbeurgh Herman , Graille Marc , Séraphin Bertrand
Published: May 2011

In Saccharomyces cerevisiae, the putative 2-OG-Fe(II) dioxygenase Tpa1 and its partner Ett1 have been shown to impact mRNA decay and translation. Hence, inactivation of these factors was shown to influence stop codon read-though. In addition, Tpa1 represses, by an unknown mechanism, genes regulated by Hap1, a transcription factor involved in the response to levels of heme and O2. The Schizosaccharomyces pombe orthologs of Tpa1 and Ett1, Ofd1, and its partner Nro1, respectively, have been shown to regulate the stability of the Sre1 transcription factor in response to oxygen levels. To gain insight into the function of Nro1/Ett1, we have solved the crystal structure of the S. pombe Nro1 protein deleted of its 54 N-terminal residues. Nro1 unexpectedly adopts a Tetratrico Peptide Repeat (TPR) fold, a motif often responsible for protein or peptide binding. Two ligands, a sulfate ion and an unknown molecule, interact with a cluster of highly conserved amino acids on the protein surface. Mutation of these residues demonstrates that these ligand binding sites are essential for Ett1 function in S. cerevisiae, as investigated by assaying for efficient translation termination.
Sharing and archiving nucleic acid structure mapping data
Authors: Rocca-Serra Philippe , Bellaousov Stanislav , Birmingham Amanda , Chen Chunxia , Cordero Pablo , Das Rhiju , Davis-Neulander Lauren , Duncan Caia D.S. , Halvorsen Matthew , Knight Rob , Leontis Neocles B. , Mathews David H. , Ritz Justin , Stombaugh Jesse , Weeks Kevin M. , Zirbel Craig L. , Laederach Alain
Published: May 2011

Nucleic acids are particularly amenable to structural characterization using chemical and enzymatic probes. Each individual structure mapping experiment reveals specific information about the structure and/or dynamics of the nucleic acid. Currently, there is no simple approach for making these data publically available in a standardized format. We therefore developed a standard for reporting the results of single nucleotide resolution nucleic acid structure mapping experiments, or SNRNASMs. We propose a schema for sharing nucleic acid chemical probing data that uses generic public servers for storing, retrieving, and searching the data. We have also developed a consistent nomenclature (ontology) within the Ontology of Biomedical Investigations (OBI), which provides unique identifiers (termed persistent URLs, or PURLs) for classifying the data. Links to standardized data sets shared using our proposed format along with a tutorial and links to templates can be found at http://snrnasm.bio.unc.edu.
Between-Method Differences in Prostate-Specific Antigen Assays Affect Prostate Cancer Risk Prediction by Nomograms
Authors: Stephan Carsten , Siemßen Kerstin , Cammann Henning , Friedersdorff Frank , Deger Serdar , Schrader Mark , Miller Kurt , Lein Michael , Jung Klaus , Meyer Hellmuth-Alexander
Published: May 2011

BACKGROUND

To date, no published nomogram for prostate cancer (PCa) risk prediction has considered the between-method differences associated with estimating concentrations of prostate-specific antigen (PSA).

METHODS

Total PSA (tPSA) and free PSA were measured in 780 biopsy-referred men with 5 different assays. These data, together with other clinical parameters, were applied to 5 published nomograms that are used for PCa detection. Discrimination and calibration criteria were used to characterize the accuracy of the nomogram models under these conditions.

RESULTS

PCa was found in 455 men (58.3%), and 325 men had no evidence of malignancy. Median tPSA concentrations ranged from 5.5 μg/L to 7.04 μg/L, whereas the median percentage of free PSA ranged from 10.6% to 16.4%. Both the calibration and discrimination of the nomograms varied significantly across different types of PSA assays. Median PCa probabilities, which indicate PCa risk, ranged from 0.59 to 0.76 when different PSA assays were used within the same nomogram. On the other hand, various nomograms produced different PCa probabilities when the same PSA assay was used. Although the ROC curves had comparable areas under the ROC curve, considerable differences were observed among the 5 assays when the sensitivities and specificities at various PCa probability cutoffs were analyzed.

CONCLUSIONS

The accuracy of the PCa probabilities predicted according to different nomograms is limited by the lack of agreement between the different PSA assays. This difference between methods may lead to unacceptable variation in PCa risk prediction. A more cautious application of nomograms is recommended.
Phosphorylation of Histone H2A.X as an Early Marker of Neuronal Endangerment following Seizures in the Adult Rat Brain
Authors: Crowe Samantha L. , Tsukerman Susanna , Gale Karen , Jorgensen Timothy J. , Kondratyev Alexei D.
Published: May 2011

The phosphorylated form of histone H2A.X (γ-H2AX) is a well documented early, sensitive, and selective marker of DNA double-strand breaks (DSBs). Previously, we found that excessive glutamatergic activity increased γ-H2AX in neuronsin vitro.Here, we evaluated γ-H2AX formation in the adult rat brain following neuronal excitation evoked by seizure activityin vivo. We found that brief, repeated electroconvulsive shock (ECS)-induced seizures (three individual seizures within 60 min) did not trigger an increase γ-H2AX immunostaining. In contrast, a cluster of 5–7 individual seizures evoked by kainic acid (KA) rapidly (within 30 min) induced γ-H2AX in multiple neuronal populations in hippocampus and entorhinal cortex. This duration of seizure activity is well below threshold for induction of neuronal cell death, indicating that the γ-H2AX increase occurs in response to sublethal insults. Moreover, an increase in γ-H2AX was seen in dentate granule cells, which are resistant to cell death caused by KA-evoked seizures. With as little as a 5 min duration of status epilepticus (SE), γ-H2AX increased in CA1, CA3, and entorhinal cortex to a greater extent than that observed after the clusters of individual seizures, with still greater increases after 120 min of SE. Our findings provide the first direct demonstration that DNA DSB damage occursin vivoin the brain following seizures. Furthermore, we found that the γ-H2AX increase caused by 120 min of SE was prevented by neuroprotective preconditioning with ECS-evoked seizures. This demonstrates that DNA DSB damage is an especially sensitive indicator of neuronal endangerment and that it is responsive to neuroprotective intervention.