bluuebunny/crossref_metadata_2025 huggingface dataset:
Simvastatin inhibits oxidative stress via the activation of nuclear factor erythroid 2‐related factor 2 signaling in trophoblast cells
Authors: Chigusa Yoshitsugu , Kawasaki Kaoru , Kondoh Eiji , Mogami Haruta , Ujita Mari , Fujita Kohei , Tatsumi Keiji , Takeda Satoru , Konishi Ikuo
Published: November 2015

Aim

Nuclear factor erythroid 2‐related factor 2 (Nrf2) is a key transcriptional regulator against oxidative stress through the induction of antioxidant and cytoprotective genes, such as heme oxygenase 1 (HO‐1), glutamyl cysteine ligase catalytic (GCLC), and glutamyl cysteine ligase modulatory (GCLM). Nrf2 signaling is disrupted in pre‐eclamptic placentas, although increased oxidative stress is implicated in pre‐eclampsia. The aims of the study were: (i) to investigate the mechanism that underlies the impaired Nrf2 signaling in pre‐eclamptic placentas, and (ii) to examine the potential therapeutic role of statin for pre‐eclampsia.

Material and Methods

Human choriocarcinoma JAR cells were cultured under normoxia (20% O2) or hypoxia (1% O2). Small‐interfering ribonucleic acids were used to knockdown Nrf2. Real‐time quantitative reverse transcriptase polymerase chain reaction and Western blotting were used to evaluate the influence of oxidative stress (H2O2 100 μM) and simvastatin (50 μM) on Nrf2 and its target genes. Reactive oxygen species levels were analyzed by flow cytometry in immortalized human trophoblast TCL1 cells treated with or without H2O2 (100 μM) ± simvastatin (50 μM).

Results

Nuclear factor erythroid 2‐related factor 2 activation was significantly suppressed under hypoxic conditions. Nrf2 knockdown resulted in insufficient enhancement of HO‐1, GCLC and GCLM expression under oxidative stress. In contrast, Nrf2 signaling was augmented by simvastatin, which suppressed the induction of oxidative stress in trophoblasts.

Conclusion

Hypoxia is one of the important negative regulators of Nrf2 activation, and simvastatin inhibits oxidative stress through the activation of Nrf2 signaling in trophoblasts, indicating the potential therapeutic role of statin for pre‐eclampsia.
Codes of Contention: Building Regulations in Colonial Bombay, 1870‐1912
Authors: Issar Sukriti
Published: November 2015

This paper investigates the contentious institutionalization of building codes in colonial Bombay. Based on original archival research, the paper demonstrates that building codes were inflected with a discourse of moral regulation that masked the material interests of the state. Resistance to these regulations came from many quarters; conflicts within the state, public opinion expressed in the press, and political strategizing of residents and landowners in the public sphere. The paper argues for greater attention to the historically variable interconnections between power and resistance in specific empirical contexts.
Growth Mixture Modeling of Adolescent Body Mass Index Development: Longitudinal Patterns of Internalizing Symptoms and Physical Activity
Authors: Ames Megan E. , Wintre Maxine G.
Published: November 2015

Growth mixture modeling was used to identify different trajectories of body mass index (BMI) among adolescents ages 10–15 from a national sample. Three distinct classes were found for both boys and girls: “normative” (90.9% and 89.7%), “high increasing” (6.3% and 7.4%), and “decreasing” (2.8% and 2.9%). Multinomial logistic regression identified family income as predictive of class membership for boys and pubertal status and being rural as predictive for girls. Parent‐reported health was a common predictor across gender. Growth curves of internalizing symptoms and physical activity were modeled to explore trends across classes. Findings highlight complexities in the relations between BMI, internalizing symptoms, and physical activity in this developmental period.
The Scientific and the Social in Implementing Atkins v. Virginia
Authors: Pifer Natalie A.
Published: November 2015

Atkins v. Virginia (2002) categorically exempts intellectually disabled defendants from execution, yet some constitutionally suspect punishments suggest a gap between law and practice. This article moves beyond critiquing Atkins' formal implementation to provide a decentered analysis of the Atkins gap focused on the category of intellectual disability. It explores how drawing boundaries around intellectual disability in capital cases requires law to grapple with fluid scientific and social constructs through a study of how courts operationalize intellectual disability in capital cases. It draws from literatures considering the construction of intellectual disability and law's relationship to the scientific and the social and finds that this intersection first enables a conceptual disconnect between scientific and legal constructions of intellectual disability and, second, invites the use of stereotypes to inform the category. These processes undermine Atkins'—and other categorical exemptions'—ability to functionally limit extreme punishments and also reveal law as mutually constitutive.
Population genetic evidence for cold adaptation in European Drosophila melanogaster populations
Authors: Božičević Vedran , Hutter Stephan , Stephan Wolfgang , Wollstein Andreas
Published: November 2015

We studied Drosophila melanogaster populations from Europe (the Netherlands and France) and Africa (Rwanda and Zambia) to uncover genetic evidence of adaptation to cold. We present here four lines of evidence for genes involved in cold adaptation from four perspectives: (i) the frequency of SNPs at genes previously known to be associated with chill‐coma recovery time (CCRT), startle reflex (SR) and resistance to starvation stress (RSS) vary along environmental gradients and therefore among populations; (ii) SNPs of genes that correlate significantly with latitude and altitude in African and European populations overlap with SNPs that correlate with a latitudinal cline from North America; (iii) at the genomewide level, the top candidate genes are enriched in gene ontology (GO) terms that are related to cold tolerance; (iv) GO enriched terms from North American clinal genes overlap significantly with those from Africa and Europe. Each SNP was tested in 10 independent runs of Bayenv2, using the median Bayes factors to ascertain candidate genes. None of the candidate genes were found close to the breakpoints of cosmopolitan inversions, and only four candidate genes were linked to QTLs related to CCRT. To overcome the limitation that we used only four populations to test correlations with environmental gradients, we performed simulations to estimate the power of our approach for detecting selection. Based on our results, we propose a novel network of genes that is involved in cold adaptation.
The dying of the light: crepuscular activity in Culicoides and impact on light trap efficacy at temperate latitudes
Authors: MEISWINKEL R. , ELBERS A. R. W.
Published: November 2015

The light trap is the tool of choice for conducting large‐scale Culicoides (Diptera: Ceratopogonidae) vector surveillance programmes. Its efficacy is in doubt, however. To assess this, hourly changes in Culicoides activity over the 24‐h diel were determined comparatively by way of light trapping and aerial sweeping, and correlated against light intensity. In the Netherlands, sweeping around cattle at pasture revealed that, in early summer, Culicoides are active throughout the diel, and that their abundance peaks during the crepuscular period and falls to a low during the brightest hours of the day. By contrast, the light trap was able to accumulate Culicoides only at night (i.e. after illuminance levels had dropped to 0 lux and midge activity had begun to decline). Although Culicoides chiopterus and species of the Culicoides obsoletus complex were similarly abundant around livestock, they differed critically in their hours of peak activity, being largely diurnal and nocturnal, respectively. This polarity helps to explain why, routinely, the C. obsoletus complex dominates light trap collections and C. chiopterus does not. Inability to accumulate Culicoides at light intensity levels above 0 lux means that, at ever‐higher latitudes, particularly beyond 45° N, the progressive northward lengthening of the twilight period will have an increasingly adverse impact upon the efficacy of the light trap as a vector surveillance tool.
Spinocerebellar degeneration: Discrepancies between clinical and pathological diagnoses
Authors: Yamada Mitsunori , Toyoshima Yasuko , Makifuchi Takao , Kakita Akiyoshi , Takahashi Hitoshi
Published: November 2015

To improve the diagnostic accuracy of sporadic spinocerebellar degeneration (SCD), we assessed the clinical and pathological data of 1494 consecutive autopsy cases. The number of patients who received a diagnosis of sporadic SCD (including multiple system atrophy) either clinically or pathologically was 19 (1.3%). We identified six cases with clinical misdiagnoses of SCD that were confirmed pathologically as progressive supranuclear palsy (PSP, four cases), basilar artery thrombosis (one case) and unclassified tauopathy (one case). The total number of patients who received a clinical diagnosis of sporadic SCD was 93 and the positive predictive value was 93.5%. We also identified 13 autopsy cases that were pathologically confirmed as SCD, but had been clinically misdiagnosed as having other disorders. Their clinical diagnoses comprised progressive supranuclear palsy (five cases) and Parkinson's disease (PD, four cases), as well as parkinsonism with dementia, amyotrophic lateral sclerosis, paraneoplastic syndrome and multiple cerebral infarction (one case each). The results indicate that it is often difficult to distinguish PSP and PD from SCD, because of the atypical combination of symptoms or atypical timing of the appearance of symptoms, such as severe autonomic failure, cognitive impairment, poor L‐dopa responsiveness, early cerebellar signs and obvious vertical gaze palsy.
Understanding Fallible Warrant and Fallible Knowledge: Three Proposals
Authors: Hetherington Stephen
Published: November 2015

One of contemporary epistemology's more important conceptual challenges is that of understanding the nature of fallibility. Part of why this matters is that it would contribute to our understanding the natures of fallible warrant and fallible knowledge. This article evaluates two candidates – and describes a shared form of failing. Each is concealedly infallibilist. This failing is all‐too‐representative of the difficulty of doing justice to the notion of fallibility within the notions of fallible warrant and fallible knowledge. The article ends with a proposal for an improved (even if schematic) form of conception of fallible warrant and fallible knowledge.
Correlation between neurochemical metabolism and memory function in adolescent patients with depression: A multi‐voxel 1H magnetic resonance spectroscopy study
Authors: Mao Ning , Fang Junfang , Xie Haizhu , Liu Xinjiang , Jiang Xingyue , Wang Guangbin , Cui Minghu , Wang Bin , Liu Qiang
Published: November 2015

Aims

We utilized multi‐voxel proton magnetic resonance spectroscopy (1H‐MRS) to detect biochemical abnormalities in dorsolateral prefrontal white matter and anterior cingulate gray matter and to determine the correlation of biochemical changes with memory function in depressed adolescents.

Methods

A total of 24 depressed patients and 23 healthy controls were enrolled in this study. MRS was performed to assess the N‐acetylaspartate (NAA)/creatine Cr and choline (Cho)/Cr ratios in dorsolateral prefrontal white matter and anterior cingulate gray matter of participants. Memory function was measured on the basis of Wechsler Memory Scale scores, and depression was diagnosed on the basis of clinical observation, interview, and Hamilton Depression Rating Scale scores.

Results

Compared with controls, depressed patients had significantly lower NAA/Cr and Cho/Cr ratios in left dorsolateral prefrontal white matter and lower NAA/Cr ratios in right dorsolateral prefrontal white matter (P < 0.05). No biochemical differences were identified in the bilateral anterior cingulate gray matter between the two groups. Nevertheless, the depressed patients showed significantly lower memory quotient than controls (P < 0.05). The NAA/Cr ratio in dorsolateral prefrontal white matter positively correlated with memory quotient (left: P < 0.01; right: P < 0.05).

Conclusions

These findings suggest that biochemical abnormalities in prefrontal white matter are involved in the pathophysiology of adolescent depression. In particular, such abnormalities are already present at the early stage of the disorder, and low NAA/Cr in bilateral anterior frontal white matter may be associated with memory impairment and related neuropathology.
Classifying eating‐related problems among institutionalized people with dementia
Authors: Shinagawa Shunichiro , Honda Kazuki , Kashibayashi Tetsuo , Shigenobu Kazue , Nakayama Kazuhiko , Ikeda Manabu
Published: November 2015

Aims

Various eating‐related problems are commonly observed among people with dementia, and these problems place a huge burden on the caregivers. An appropriate classification of these problems is important in order to understand their underlying mechanisms and to develop a therapeutic approach for managing them. The aim of this study was to develop a possible classification of eating‐related problems and to reveal the background factors affecting each of these problems across various conditions causing dementia.

Methods

The participants were 208 institutionalized patients with a diagnosis of dementia. Care staff were asked to report all kinds of eating‐related problems that they observed. After the nurses' responses were analyzed, 24 items relating to eating‐related problems were extracted. A factor analysis of these 24 items was conducted, followed by a logistic regression analysis to investigate the independent variables that most affected each of the eating‐related factors.

Results

Four factors were obtained. Factor 1 was overeating, factor 2 was swallowing problems, factor 3 was decrease in appetite, and factor 4 was obsession with food. Each factor was associated with different background variables, including Mini‐Mental State Examination scores, Clinical Dementia Ratings, and neuropsychiatric symptoms.

Conclusions

This study suggests that eating‐related problems are common across conditions causing dementia and should be separately considered in order to understand their underlying mechanisms.
Overlapping Consensus Thin and Thick: John Rawls and Simone Weil
Authors: Heifetz Aviad , Minelli Enrico
Published: November 2015

John Rawls and Simone Weil presented two distinct conceptions of political justice, aimed at articulating a common ethos in an inherently heterogeneous society. The terms of the former, chiefly concerned with the distribution of primary goods, underwrite much of today's Western democracies political liberalism. The terms of the latter, chiefly concerned with the way interaction is organised in social activities in view of the body and soul's balancing pairs of needs, are less well known. We explain the sense in which the overlapping consensus in Weil's notion of political justice is “thicker”, and may thus deserve more attention – alongside that of Rawls – for substantiating a democratic ethos within political liberalism.
Estimating Multivariate Volatility Models Equation by Equation
Authors: Francq Christian , Zakoïan Jean-Michel
Published: November 2015

The paper investigates the estimation of a wide class of multivariate volatility models. Instead of estimating an m-multivariate volatility model, a much simpler and numerically efficient method consists in estimating m univariate generalized auto-regressive conditional heteroscedasticity type models equation by equation in the first step, and a correlation matrix in the second step. Strong consistency and asymptotic normality of the equation-by-equation estimator are established in a very general framework, including dynamic conditional correlation models. The equation-by-equation estimator can be used to test the restrictions imposed by a particular multivariate generalized auto-regressive conditional heteroscedasticity specification. For general constant conditional correlation models, we obtain the consistency and asymptotic normality of the two-step estimator. Comparisons with the global method, in which the model parameters are estimated in one step, are provided. Monte Carlo experiments and applications to financial series illustrate the interest of the approach.
Helicobacter cinaedi bacteremia in four renal transplant patients: clinical features and an important suggestion regarding the route of infection
Authors: Imafuku A. , Araoka H. , Tanaka K. , Marui Y. , Sawa N. , Ubara Y. , Takaichi K. , Ishii Y. , Tomikawa S.
Published: November 2015

Helicobacter cinaedi can cause bacteremia mainly in immunocompromised patients. We present the clinical characteristics of H. cinaedi bacteremia in 4 renal transplant patients. Interestingly, all cases showed triggers of bacterial translocation: 2 cases developed after colonic perforation caused by diverticulitis, 1 case developed post cholecystectomy, and the remaining patient had chronic diarrhea. Accordingly, bacterial translocation caused by severe gastrointestinal complication could be a cause of H. cinaedi bacteremia.
Preoperative platelet transfusions and perioperative red blood cell requirements in patients with thrombocytopenia undergoing noncardiac surgery
Authors: Warner Matthew A. , Jia Qing , Clifford Leanne , Wilson Gregory , Brown Michael J. , Hanson Andrew C. , Schroeder Darrell R. , Kor Daryl J.
Published: November 2015

BACKGROUND

Perioperative hemorrhage impacts patient outcomes and health care resource utilization, yet the risks of transfusion therapies are significant. In patients with preoperative thrombocytopenia, the effects of prophylactic preoperative platelet (PLT) transfusion on perioperative bleeding complications remain uncertain.

STUDY DESIGN AND METHODS

This is a retrospective cohort study of noncardiac surgical patients between January 1, 2008, and December 31, 2011. Propensity‐adjusted analyses were used to evaluate associations between preoperative thrombocytopenia, preoperative PLT transfusion, and the outcomes of interest, with a primary outcome of perioperative red blood cell (RBC) transfusion.

RESULTS

A total of 13,978 study participants were included; 860 (6.2%) had a PLT count of not more than 100 × 109/L with 71 (8.3%) receiving PLTs preoperatively. Administration of PLTs was associated with higher rates of perioperative RBC transfusion (66.2% vs. 49.1%, p = 0.0065); however, in propensity‐adjusted analysis there was no significant difference between groups (odds ratio [OR] [95% confidence interval {95% CI}], 1.68 [0.95‐2.99]; p = 0.0764]. Patients receiving PLTs had higher rates of intensive care unit (ICU) admission (OR [95% CI], 1.95 [1.10‐3.46]; p = 0.0224) and longer hospital lengths of stay (estimate [95% bootstrap CI], 7.2 [0.8‐13.9] days; p = 0.0006) in propensity‐adjusted analyses.

CONCLUSION

Preoperative PLT transfusion did not attenuate RBC requirements in patients with thrombocytopenia undergoing noncardiac surgery. Moreover, preoperative PLT transfusion was associated with increased ICU admission rates and hospital duration. These findings suggest that more conservative management of preoperative thrombocytopenia may be warranted.
Influence of the Hip Joint Modeling Approaches on the Kinematics of Human Gait
Authors: Costa João , Peixoto Joaquim , Moreira Pedro , Pedro Souto António , Flores Paulo , Lankarani Hamid M.
Published: November 2015

The influence of the hip joint formulation on the kinematic response of the model of human gait is investigated throughout this work. To accomplish this goal, the fundamental issues of the modeling process of a planar hip joint under the framework of multibody systems are revisited. In particular, the formulations for the ideal, dry, and lubricated revolute joints are described and utilized for the interaction of femur head inside acetabulum or the hip bone. In this process, the main kinematic and dynamic aspects of hip joints are analyzed. In a simple manner, the forces that are generated during human gait, for both dry and lubricated hip joint models, are computed in terms of the system's state variables and subsequently introduced into the dynamics equations of motion of the multibody system as external generalized forces. Moreover, a human multibody model is considered, which incorporates the different approaches for the hip articulation, namely, ideal joint, dry, and lubricated models. Finally, several computational simulations based on different approaches are performed, and the main results are presented and compared to identify differences among the methodologies and procedures adopted in this work. The input conditions to the models correspond to the experimental data capture from an adult male during normal gait. In general, the obtained results in terms of positions do not differ significantly when different hip joint models are considered. In sharp contrast, the velocity and acceleration plotted vary significantly. The effect of the hip joint modeling approach is clearly measurable and visible in terms of peaks and oscillations of the velocities and accelerations. In general, with the dry hip model, intrajoint force peaks can be observed, which can be associated with the multiple impacts between the femur head and the cup. In turn, when the lubricant is present, the system's response tends to be smoother due to the damping effects of the synovial fluid.
A Numerical Model for the Identification of the Structural Damages in Rolling Contact Bearings Using Matrix Method of Dimensional Analysis
Authors: Jamadar I. M. , Vakharia D. P.
Published: November 2015

The damages to the structural elements, viz., inner race, outer race, rollers, cage, etc., of rolling contact bearings if not detected in time can cause tragic failures of the machineries supported by these bearings. The operating parameters like variations in the machinery speed, unbalance, operating load, etc., can cause a bearing to vibrate at higher energy levels and consequently will accelerate its wear. An attempt is made in this study, and a generalized model is developed using matrix method of dimensional analysis (MMDA) that predicted the response and correlated the dependent parameter, i.e., response with the significant independent parameters. Combined use of response surface methodology (RSM) is made to explore the dependence of various factors such as size of the defect, unbalance, speed, and their interactions on the vibration characteristics of the bearings. It is observed from the study that the model developed based on the MMDA has provided an efficient approach in recognizing the damaged bearing state, which can be easily implemented in the condition-based preventive maintenance strategies. Also, the effectiveness of MMDA as compared to the conventional Buckingham's pi theorem in the dimensional analysis (DA) practice, especially in the problems involving multiple variables, is shown in this study.
Effects of Anisotropic Slip on the Elastohydrodynamic Lubrication of Circular Contacts
Authors: Chen Qie-Da , Jao Hsiang-Chin , Chu Li-Ming , Li Wang-Long
Published: November 2015

By coupling the equations of the modified Reynolds equation with the anisotropic slip effect, the piezoviscosity and piezodensity relations, the elasticity deformation equation, and the load equilibrium equation are solved simultaneously using the finite element method (FEM) for the elastohydrodynamic lubrication (EHL) of circular contact problems under constant load conditions. Results show that the film thickness is more sensitive to the slip length in a sliding direction (x-direction) than to the slip length in a transverse direction (y-direction). A slip in the y-direction concentrates the pressure toward the center region, and the film collects toward the central region and possesses a deeper dimple. The central pressure and coefficient of friction (COF) increase as the slip length in the y-direction increases. On the contrary, the central pressure and COF decrease as the slip length in the x-direction increases. Detailed results and animations for film thicknesses and pressure distributions are available under the “Supplemental Data” tab for this paper on the ASME Digital Collection.
Hydrodynamic Behaviors of the Gas-Lubricated Film in Wedge-Shaped Microchannel
Authors: Zhang Xueqing , Chen Qinghua , Liu Juanfang
Published: November 2015

As for the micro gas bearing operating at a high temperature and speed, one wedge-shaped microchannel is established, and the hydrodynamic properties of the wedge-shaped gas film are comprehensively investigated. The Reynolds equation, modified Reynolds equation, energy equation, and Navier–Stokes equations are employed to describe and analyze the hydrodynamics of the gas film. Furthermore, the comparisons among the hydrodynamic properties predicted by various models were performed for the different wedge factors and the different wall temperatures. The results show that coupling the simplified energy equation with the Reynolds or modified Reynolds equations has an obvious effect on the change of the friction force acting on the horizontal plate and the load capacity of the gas film at the higher wedge factor and the lower wall temperature. The velocity slip weakens the squeeze of the gas film and strengths the gas backflow. A larger wedge factor or a higher wall temperature leads to a higher gas film temperature and thus enhances the rarefaction effect. As the wall temperature is elevated, the load capacity obtained by the Reynolds equation increases, while the results by the Navier–Stokes equations coupled with the full energy equation rapidly decrease. Additionally, the vertical flow across the gas film in the Navier–Stokes equations weakens the squeeze between the gas film and the tilt plate and the gas backflow.
Perfectly Elastic Axisymmetric Sinusoidal Surface Asperity Contact
Authors: Saha S. , Xu Y. , Jackson R. L.
Published: November 2015

This work presents a finite element (FE) study of a perfectly elastic axisymmetric sinusoidal-shaped asperity in contact with a rigid flat for different amplitude to wavelength ratios and a wide range of material properties. This includes characterizing the pressure required to cause complete contact between the surfaces. Complete contact is defined as when there is no gap remaining between two contacting surfaces. The model is designed in such a way that its axisymmetric and interaction with the adjacent asperities are considered by the effect of geometry at the base of the asperity. The numerical results are compared to the model of curved point contact for the perfectly elastic case (known as Hertz contact) and Westergaard's solution. Once properly normalized, the nondimensional contact area does not vary with nondimensional load. The critical pressure required to cause complete contact is found. The results are also curve fitted to provide an expression for the contact area as a function of load over a wide range of cases for use in practical applications, such as to predict contact resistance. This could be a stepping stone to more complex models.
Efficient and Accurate Calculation of Discrete Frequency Response Functions and Impulse Response Functions
Authors: Xu Y. F. , Zhu W. D.
Published: November 2015

Modal properties of a structure can be identified by experimental modal analysis (EMA). Discrete frequency response functions (FRFs) and impulse response functions (IRFs) between response and excitation series are bases for EMA. In the calculation of a discrete FRF, the discrete Fourier transform (DFT) is applied to both response and excitation series, and a transformed series in the DFT is virtually extended to have an infinite length and be periodic with a period equal to the length of the series; the resulting periodicity can be physically incorrect in some cases, which depends on an excitation technique used. An efficient and accurate methodology for calculating discrete FRFs and IRFs is proposed here, by which fewer spectral lines are needed and accuracies of resulting FRFs and IRFs can be maintained. The relationship between an IRF from the proposed methodology and that from the least-squares (LS) method is shown. A coherence function extended from a new type of coherence functions is used to evaluate qualities of FRFs and IRFs from the proposed methodology in the frequency domain. The extended coherence function can yield meaningful values even with response and excitation series of one sampling period. Based on the extended coherence function, a fitting index is used to evaluate overall qualities of the FRFs and IRFs. The proposed methodology was numerically and experimentally applied to a two degrees-of-freedom (2DOF) mass–spring–damper system and an aluminum plate to estimate their FRFs and IRFs, respectively. In the numerical example, FRFs and IRFs from the proposed methodology agree well with theoretical ones. In the experimental example, an FRF and its associated IRF from the proposed methodology with a random impact series agreed well with benchmark ones from a single impact test.
Limits of the Kelvin Voigt Model for the Analysis of Wave Propagation in Monoatomic Mass-Spring Chains
Authors: Palermo Antonio , Marzani Alessandro
Published: November 2015

In this study, the effect of energy dissipation on harmonic waves propagating in one-dimensional monoatomic linear viscoelastic mass-spring chains is investigated. In particular, first dispersion laws in terms of wavenumber, attenuation, and wave propagation velocities (phase, group, and energy) for a generic viscoelastic mass-spring chain are derived from the homologous linear elastic (LE) expressions in force of the correspondence principle. A new formula for the energy velocity is introduced to account for energy dissipation. Next, such relations are specified for the Kelvin Voigt (KV) and the standard linear solid (SLS) rheological models. The analysis of the KV mass-spring chain in the high-frequency regime proves that the so-called wavenumber-gap is not related to energy dissipation, as assumed in previous studies, but is due to the nonphysical rigid behavior of the model at high frequencies. The SLS mass-spring chain, in fact, does not show any wavenumber-gap and at high frequencies recovers the wavenumber dispersion curve of the LE system. The behavior of the energy velocity for the different mass-spring chains confirms this conclusion.
Experimental Validation of Wave Vibration Analysis of Complex Vibrations in a Two-Story Metallic Space Frame Based on the Timoshenko Bending Theory
Authors: Mei C.
Published: November 2015

In a space frame, there exist in- and out-of-plane bending, axial, and torsional vibrations. The analysis of complex vibrations in such structures has relied mostly on numerical approaches. In this study, a wave-based analytical approach is applied to obtain solutions to vibrations in space frames. Both free and forced wave vibration responses are obtained, with bending vibrations modeled using the Timoshenko theory. A two-story steel space frame is built to validate the analytical results, and good agreements have been reached between the analytical and experimental studies. The effect of torsional rigidity adjustment on the accuracy of predicted vibrational responses in structures involving rotationally nonsymmetric cross sections is also examined.
Stochastic model explains formation of cell arrays on H/O-diamond patterns
Authors: Ukraintsev Egor , Broz Antonin , Hubalek Kalbacova Marie , Kromka Alexander , Rezek Bohuslav
Published: November 2015

Cell migration plays an important role in many biological systems. A relatively simple stochastic model is developed and used to describe cell behavior on chemically patterned substrates. The model is based on three parameters: the speed of cell movement (own and external), the probability of cell adhesion, and the probability of cell division on the substrate. The model is calibrated and validated by experimental data obtained on hydrogen- and oxygen-terminated patterns on diamond. Thereby, the simulations reveal that: (1) the difference in the cell movement speed on these surfaces (about 1.5×) is the key factor behind the formation of cell arrays on the patterns, (2) this difference is provided by the presence of fetal bovine serum (validated by experiments), and (3) the directional cell flow promotes the array formation. The model also predicts that the array formation requires mean distance of cell travel at least 10% of intended stripe width. The model is generally applicable for biosensors using diverse cells, materials, and structures.
Partial pressure measurement standard for characterizing partial pressure analyzers and measuring outgassing rates
Authors: Jousten Karl , Putzke Stephan , Buthig Joachim
Published: November 2015

In this work, a measurement standard was established for partial pressures in high and ultrahigh vacuum conditions. Three (or more, with higher uncertainty) different gases with known partial pressures from 10−8 to 10−2 Pa can be generated in a calibration chamber of an ultrahigh vacuum system by a continuous expansion method. The ratio between two partial pressures can range from 10−6 to 1. The readings of partial pressure analyzers can be calibrated by comparing them to known partial pressures. The calibration chamber is connected to a sample chamber, where outgassing samples can be inserted via a load lock. With an in situ calibrated partial pressure analyzer, the outgassing rate from the samples can be measured in a traceable way to the international systems of units.
Evaluation of MRI and cannabinoid type 1 receptor PET templates constructed using DARTEL for spatial normalization of rat brains
Authors: Kronfeld Andrea , Buchholz Hans‐Georg , Maus Stephan , Reuss Stefan , Müller‐Forell Wibke , Lutz Beat , Schreckenberger Mathias , Miederer Isabelle
Published: November 2015

Purpose:

Image registration is one prerequisite for the analysis of brain regions in magnetic‐resonance‐imaging (MRI) or positron‐emission‐tomography (PET) studies. Diffeomorphic anatomical registration through exponentiated Lie algebra (DARTEL) is a nonlinear, diffeomorphic algorithm for image registration and construction of image templates. The goal of this small animal study was (1) the evaluation of a MRI and calculation of several cannabinoid type 1 (CB1) receptor PET templates constructed using DARTEL and (2) the analysis of the image registration accuracy of MR and PET images to their DARTEL templates with reference to analytical and iterative PET reconstruction algorithms.

Methods:

Five male Sprague Dawley rats were investigated for template construction using MRI and [18F]MK‐9470 PET for CB1 receptor representation. PET images were reconstructed using the algorithms filtered back‐projection, ordered subset expectation maximization in 2D, and maximum a posteriori in 3D. Landmarks were defined on each MR image, and templates were constructed under different settings, i.e., based on different tissue class images [gray matter (GM), white matter (WM), and GM + WM] and regularization forms (“linear elastic energy,” “membrane energy,” and “bending energy”). Registration accuracy for MRI and PET templates was evaluated by means of the distance between landmark coordinates.

Results:

The best MRI template was constructed based on gray and white matter images and the regularization form linear elastic energy. In this case, most distances between landmark coordinates were <1 mm. Accordingly, MRI‐based spatial normalization was most accurate, but results of the PET‐based spatial normalization were quite comparable.

Conclusions:

Image registration using DARTEL provides a standardized and automatic framework for small animal brain data analysis. The authors were able to show that this method works with high reliability and validity. Using DARTEL templates together with nonlinear registration algorithms allows for accurate spatial normalization of combined MRI/PET or PET‐only studies.
TestDose: A nuclear medicine software based on Monte Carlo modeling for generating gamma camera acquisitions and dosimetry
Authors: Garcia Marie‐Paule , Villoing Daphnée , McKay Erin , Ferrer Ludovic , Cremonesi Marta , Botta Francesca , Ferrari Mahila , Bardiès Manuel
Published: November 2015

Purpose:

The TestDose platform was developed to generate scintigraphic imaging protocols and associated dosimetry by Monte Carlo modeling. TestDose is part of a broader project (www.dositest.com) whose aim is to identify the biases induced by different clinical dosimetry protocols.

Methods:

The TestDose software allows handling the whole pipeline from virtual patient generation to resulting planar and SPECT images and dosimetry calculations. The originality of their approach relies on the implementation of functional segmentation for the anthropomorphic model representing a virtual patient. Two anthropomorphic models are currently available: 4D XCAT and ICRP 110. A pharmacokinetic model describes the biodistribution of a given radiopharmaceutical in each defined compartment at various time‐points. The Monte Carlo simulation toolkit gate offers the possibility to accurately simulate scintigraphic images and absorbed doses in volumes of interest. The TestDose platform relies on gate to reproduce precisely any imaging protocol and to provide reference dosimetry. For image generation, TestDose stores user's imaging requirements and generates automatically command files used as input for gate. Each compartment is simulated only once and the resulting output is weighted using pharmacokinetic data. Resulting compartment projections are aggregated to obtain the final image. For dosimetry computation, emission data are stored in the platform database and relevant gate input files are generated for the virtual patient model and associated pharmacokinetics.

Results:

Two samples of software runs are given to demonstrate the potential of TestDose. A clinical imaging protocol for the Octreoscan™ therapeutical treatment was implemented using the 4D XCAT model. Whole‐body “step and shoot” acquisitions at different times postinjection and one SPECT acquisition were generated within reasonable computation times. Based on the same Octreoscan™ kinetics, a dosimetry computation performed on the ICRP 110 model is also presented.

Conclusions:

The proposed platform offers a generic framework to implement any scintigraphic imaging protocols and voxel/organ‐based dosimetry computation. Thanks to the modular nature of TestDose, other imaging modalities could be supported in the future such as positron emission tomography.
Quantifying the performance of in vivo portal dosimetry in detecting four types of treatment parameter variations
Authors: Bojechko C. , Ford E. C.
Published: November 2015

Purpose:

To quantify the ability of electronic portal imaging device (EPID) dosimetry used during treatment (in vivo) in detecting variations that can occur in the course of patient treatment.

Methods:

Images of transmitted radiation from in vivo EPID measurements were converted to a 2D planar dose at isocenter and compared to the treatment planning dose using a prototype software system. Using the treatment planning system (TPS), four different types of variability were modeled: overall dose scaling, shifting the positions of the multileaf collimator (MLC) leaves, shifting of the patient position, and changes in the patient body contour. The gamma pass rate was calculated for the modified and unmodified plans and used to construct a receiver operator characteristic (ROC) curve to assess the detectability of the different parameter variations. The detectability is given by the area under the ROC curve (AUC). The TPS was also used to calculate the impact of the variations on the target dose–volume histogram.

Results:

Nine intensity modulation radiation therapy plans were measured for four different anatomical sites consisting of 70 separate fields. Results show that in vivo EPID dosimetry was most sensitive to variations in the machine output, AUC = 0.70 − 0.94, changes in patient body habitus, AUC = 0.67 − 0.88, and systematic shifts in the MLC bank positions, AUC = 0.59 − 0.82. These deviations are expected to have a relatively small clinical impact [planning target volume (PTV) D99 change <7%]. Larger variations have even higher detectability. Displacements in the patient's position and random variations in MLC leaf positions were not readily detectable, AUC < 0.64. The D99 of the PTV changed by up to 57% for the patient position shifts considered here.

Conclusions:

In vivo EPID dosimetry is able to detect relatively small variations in overall dose, systematic shifts of the MLC's, and changes in the patient habitus. Shifts in the patient's position which can introduce large changes in the target dose coverage were not readily detected.
Validation of a method for in vivo 3D dose reconstruction for IMRT and VMAT treatments using on‐treatment EPID images and a model‐based forward‐calculation algorithm
Authors: Van Uytven Eric , Van Beek Timothy , McCowan Peter M. , Chytyk‐Praznik Krista , Greer Peter B. , McCurdy Boyd M. C.
Published: November 2015

Purpose:

Radiation treatments are trending toward delivering higher doses per fraction under stereotactic radiosurgery and hypofractionated treatment regimens. There is a need for accurate 3D in vivo patient dose verification using electronic portal imaging device (EPID) measurements. This work presents a model‐based technique to compute full three‐dimensional patient dose reconstructed from on‐treatment EPID portal images (i.e., transmission images).

Methods:

EPID dose is converted to incident fluence entering the patient using a series of steps which include converting measured EPID dose to fluence at the detector plane and then back‐projecting the primary source component of the EPID fluence upstream of the patient. Incident fluence is then recombined with predicted extra‐focal fluence and used to calculate 3D patient dose via a collapsed‐cone convolution method. This method is implemented in an iterative manner, although in practice it provides accurate results in a single iteration. The robustness of the dose reconstruction technique is demonstrated with several simple slab phantom and nine anthropomorphic phantom cases. Prostate, head and neck, and lung treatments are all included as well as a range of delivery techniques including VMAT and dynamic intensity modulated radiation therapy (IMRT).

Results:

Results indicate that the patient dose reconstruction algorithm compares well with treatment planning system computed doses for controlled test situations. For simple phantom and square field tests, agreement was excellent with a 2%/2 mm 3D chi pass rate ≥98.9%. On anthropomorphic phantoms, the 2%/2 mm 3D chi pass rates ranged from 79.9% to 99.9% in the planning target volume (PTV) region and 96.5% to 100% in the low dose region (>20% of prescription, excluding PTV and skin build‐up region).

Conclusions:

An algorithm to reconstruct delivered patient 3D doses from EPID exit dosimetry measurements was presented. The method was applied to phantom and patient data sets, as well as for dynamic IMRT and VMAT delivery techniques. Results indicate that the EPID dose reconstruction algorithm presented in this work is suitable for clinical implementation.
The Effectiveness of Open Repair Versus Percutaneous Repair for an Acute Achilles Tendon Rupture
Authors: Krueger Heidi , David Shannon
Published: November 2015

Clinical Scenario:

There are 2 approaches available for surgical repair of the Achilles tendon: open or percutaneous. However, there is controversy over which repair is superior.

Focused Clinical Question:

Which type of surgery is better in providing the best overall patient outcome, open or percutaneous repair, in physically active men and women with acute Achilles tendon ruptures?

Summary of Search, “Best Evidence” Appraised, and Key Findings:

The literature was searched for studies of level 3 evidence or higher that investigated the effectiveness of open repair versus percutaneous repair on acute Achilles tendon ruptures in physically active men and women. The literature search resulted in 3 studies for possible inclusion. All 3 good-quality studies were included.

Clinical Bottom Line:

There is supporting evidence to indicate that percutaneous repair is the best option for Achilles tendon surgery when it comes to the physically active population. Percutaneous repair has faster surgery times, less risk of complications, and faster recovery times over having an open repair, although it is acknowledged that every patient has a different situation and best individual option may vary patient to patient.
Reliability of Isometric and Eccentric Isokinetic Shoulder External Rotation
Authors: Papotto Brianna M. , Rice Thomas , Malone Terry , Butterfield Timothy , Uhl Tim L.
Published: November 2015

Context: Shoulder external rotators are challenged eccentrically throughout the deceleration phase of throwing, which is thought to contribute to overuse injuries. To evaluate the effectiveness of intervention programs, as well as identifying deficits, reliable and responsive measures of isometric and eccentric shoulder external rotation are necessary. Previously, isometric measures have primarily tested a single position, and eccentric measures have not been found to have high reliability. Objective: To examine the between-days reliability of multiple-angle isometric and dynamic eccentric isokinetic testing of shoulder external rotation. Design: Repeated measures. Participants: 10 healthy subjects (age 30 ± 12 y, height 166 ± 13 cm, mass 72 ± 10 kg). Main Outcome Measures: Average isometric peak torque of shoulder external rotation at 7 angles was measured. From these values, the angle of isometric peak torque was calculated. Dynamic eccentric average peak torque, average total work, and average angle of peak torque were measured. Results: Between-days reliability was high for average peak torque during isometric contractions at all angles (ICC ≥ .85), as it was for dynamic eccentric average peak torque (ICC ≥ .97). The estimated angle of isometric peak torque (ICC ≤ .65) was not highly reliable between days. The average angle of peak torque from the eccentric testing produced inconsistent results. Average total work of dynamic eccentric shoulder external rotation was found to be highly reliable between days (ICC ≥ . 97). Conclusion: Aspects of force such as peak torque and total work in isometric and eccentric testing of the shoulder external-rotator muscles can be measured reliably between days and used to objectively evaluate shoulder strength and identify changes when they occur. Angle measurements of peak torque could provide insight into the mechanical properties of the posterior shoulder muscles but were found to be inconsistent between days.
A validated gene regulatory network and GWAS identifies early regulators of T cell–associated diseases
Authors: Gustafsson Mika , Gawel Danuta R. , Alfredsson Lars , Baranzini Sergio , Björkander Janne , Blomgran Robert , Hellberg Sandra , Eklund Daniel , Ernerudh Jan , Kockum Ingrid , Konstantinell Aelita , Lahesmaa Riita , Lentini Antonio , Liljenström H. Robert I. , Mattson Lina , Matussek Andreas , Mellergård Johan , Mendez Melissa , Olsson Tomas , Pujana Miguel A. , Rasool Omid , Serra-Musach Jordi , Stenmarker Margaretha , Tripathi Subhash , Viitala Miro , Wang Hui , Zhang Huan , Nestor Colm E. , Benson Mikael
Published: November 2015

Combining a gene regulatory network and disease association data identified early regulators of T cell–associated diseases.
Asthma super-sized
Authors: Alvarez Jessica A.
Published: November 2015

Obesity alters the immune cell profile of asthmatic lungs.
Wound healing goes green
Authors: Spiller Kara L.
Published: November 2015

Biomaterials containing photosynthetic algae promote tissue regeneration in a mouse model.
Singled out: Exploring epigenetics
Authors: Wong Ian Y.
Published: November 2015

Droplet-based microfluidics and DNA barcoding reveal the epigenetic state of chromatin in single cells.