bluuebunny/crossref_metadata_2025 huggingface dataset:
Whole Body Vibration Amplitude Levels Differentially Affect Tendon and Ligament Structural Properties
Authors: Keller Benjamin V. , Davis Matthew L. , Dahners Laurence E. , Weinhold Paul S.
Published: July 2013

Recently there have been a large number of studies examining the potential therapeutic effects of whole body vibration (WBV). Numerous studies have shown that low magnitude, high frequency vibration (LMHFV) can be anabolic for muscle and bone. Vibration has been applied to both animals and humans with notable increases in muscle cross-sectional area as well as strength [1, 4, 7]. Both high (3 G) and low (0.3 G) vibratory stimuli have been reported to initiate an increase in bone density and subsequently bone strength [3, 5]. The effects of LMHFV on other dense connective tissue types have been relatively unexplored. Legerlotz et al. investigated the response of rat Achilles tendons to 2 G WBV and found no effect on biomechanical properties [2]. However, Legerlotz’s experiment applied between 2–7 minutes of vibration a day which is significantly less than other studies as well as clinical applications. The goal of our study was to determine the effects of vibration level on the structural and material properties of intact ligaments and tendons. We hypothesized that vibration, a passive surrogate for exercise, may contribute to ligament and tendon strengthening.
Validation of an MRI-Based Method to Measure Tibiofemoral Joint Cartilage Contact Area
Authors: Allen Jerome , Gade Venkata , Barrance Peter J.
Published: July 2013

Osteoarthritis is a progressive and debilitating joint disease that is the leading cause of physical disability in industrial nations around the world [1]. It not only negatively affects the comfort and functional activity of individuals, but as a result also taxes the health care system of these countries.
Recovery of Intervertebral Disc Degeneration Post Enzymatic Treatment is Mediated by Matrix Metalloproteinases
Authors: Chahine Nadeen , Stetson Nate , Rajan Neena , Grande Daniel , Levine Mitchell
Published: July 2013

Enzymatic degradation of the intervertebral disc (IVD) with chondroitinase ABC (ChABC) reduces proteoglycan content of the IVD, thus simulating the GAG loss seen clinically in patients suffering from disc degeneration. This approach has been employed in models of disc injury in rats, rabbits and goats when administered over a large range of dosages [1–3]. Moreover, ChABC has also been used to induce repair of herniated discs in rabbits via chemonucleolysis [4, 5]. Despite the effectiveness of ChABC treatment to reduce the GAG content of the IVD, several recent studies including our own, have shown that this GAG loss is reversible at extended time points post enzymatic treatment [2,6,7]. The goal of the current study is to examine the dose dependent response of IVDs to degradation by ChABC in vivo. We hypothesize that administration of ChABC will result in dose dependent GAG loss and reduced mechanical properties. We administered ChABC at 0.1 U/ml, 1.0 U/ml and 10 U/ml and examined the changes in biomechanical properties, biochemical content, and gene expression in order to examine the biophysical and molecular mechanism by which GAG loss occurs in this model.
Parametric Investigation of Magnetic Particle Transport for Targeted Drug Delivery Applications
Authors: Cooper Daniel B. , Vlachos Pavlos P.
Published: July 2013

In recent years, there has been significant clinical and research interest in magnetic drug targeting (MDT). MDT allows the targeted delivery of drugs only to the affected sites, alleviating the rest of the body from the potential toxic or other side effects of the drug. The underlying concept of MDT is to attach drugs to small magnetic particles which can then be manipulated by a magnetic field designed to attract the drug carrying particles to the target site [1]. This will lead to increasing localized accumulation of the drug at the target site. MDT can have great implications on pharmaceutical treatments, ranging from oncology to cardiology and beyond [2, 3].
Use of Spine Robot Employing Real Time Force Control to Simulate a Pure Moment Protocol for the Subaxial Cervical Spine: An In Vitro Biomechancial Study
Authors: Wido Daniel M. , DiAngelo Denis J. , Kelly Brian P.
Published: July 2013

A standard biomechanical testing protocol for evaluation of the sub-axial cervical spine is the application of pure bending moments to the free end of the spine (with opposing end fixed) and measurement of its motion response. The pure moment protocol is often used to compare spinal fusion instrumentation and has also been used to evaluate non-fusion instrumentation (e.g. disc arthroplasty devices) [1,2]. A variety of different testing systems have been employed to implement pure moment application. In cases where the loading is applied quasi-statically using a series of weights and pulleys the spine may relax between intermittent loading phases and/or unintended loading may be applied causing experimental artifact. Our objective was to use an existing programmable robotic testing platform (Spine Robot) to develop a novel real time force control strategy to simulate pure moment loading under precisely controlled continuous movement conditions. This would serve to advance robotic testing capabilities with an end goal to simulate different protocols in the same platform, and to potentially minimize fixturing and quasi-static artifacts.
Aortic Wall Mechanics: A Geometry-Driven Problem
Authors: Raut Samarth S. , Liu Peng , Jana Anirban , Finol Ender A.
Published: July 2013

Abdominal Aortic Aneurysm (AAA) is a vascular disease that occurs predominantly in people over 60 years of age. The rupture of an AAA is a catastrophic event associated with up to a 90% mortality rate. Hence, it is important for vascular surgeons to justify the risk of repair vis-à-vis the risk of aneurysm rupture. In clinical practice, rupture risk assessment is based on measuring the maximum aneurysm diameter where 5.5 cm is accepted as the critical size for recommending (surgical or endovascular) intervention. However, this criterion is based on an extensive history of evidence-based medicine rather than an individualized assessment of the aneurysm’s potential to rupture. Primary among the biomechanical factors associated with the rupture assessment of an AAA is mechanical wall stress, which is dependent on the accuracy of the geometry reconstruction, intraluminal pressure loading and the constitutive material model used for the aortic wall. We hypothesize that in unruptured, asymptomatic AAA, the wall mechanics is the outcome of primarily the patient specific aneurysm shape and to a lesser extent, the constitutive material property model used to characterize the vascular wall. Evaluating the relative contributions of wall material properties and AAA geometry to wall mechanics estimation will increase our understanding of the factors that influence peak wall stress as an indicator for rupture risk assessment. In the present work, we evaluate the aforementioned hypothesis using a size-matched approach.
Material Properties of Aorta From Nanoindentaion Tests
Authors: Hemmasizadeh Ali , Parenti Cristina , Darvish Kurosh
Published: July 2013

Aorta is assumed as a homogenous material in current finite element models, but in fact aorta is composed of three major layers: intima, media, and adventitia with different microstructural organizations that result in different material properties. Understanding the material properties of these layers is essential for studying the local mechanisms of deformation, force transmission, and failure in aorta. The material properties of aorta wall layers were determined from nano-indentation tests. The results show that the value of shear modulus generally increases from the inner wall toward the outer wall. Aorta material time dependency was independent from the radial orientation. This study explains why aorta rupture initiates near the inner wall and propagates toward the outer wall.
Multidomain Modeling of Spatial Distributions of Tissue Optical Properties During Indentation: Mechanical Tissue Optical Clearing Devices as Diagnostic Tools
Authors: Vogt William C. , Izquierdo-Roman Alondra , Rylander Christopher G.
Published: July 2013

Soft tissues are highly heterogeneous materials comprised of water, proteins, and many types of cells. This composite configuration results in a large mismatch in index of refraction between tissue constituents, creating a high-scattering medium in the visible and near-infrared range. “Tissue optical clearing” can increase light transmission through these tissues, potentially improving both optical diagnostic and therapeutic procedures [1]. Dehydration has been shown to be a mechanism of optical clearing, and previous work has investigated mechanical loading as a method of creating reversible localized water displacement in skin using novel mechanical tissue optical clearing devices (TOCDs) [2]. In addition to potentially enhancing established light-based procedures, the principles of TOCD operation may provide a platform for a novel diagnostic tool capable of utilizing many different measurement types simultaneously.
Cyclic Strain and Interstitial Flow Modulate Cardiac Fibroblast Phenotype Through Angiotensin II and TGF-β Pathways
Authors: Galie Peter A. , Stegemann Jan P.
Published: July 2013

A fibrotic scar in the myocardium is characterized by excessive extracellular matrix deposition, loss of functioning cardiomyocytes, and the transition of healthy cardiac fibroblasts to a myofibroblast phenotype. Previous research has suggested that the myofibroblast transition is mediated by mechanical stimuli including cyclic strain [1–2] and interstitial fluid flow [3–5].
Response of Mesenchymal Stem Cells and Intervertebral Disc Cells to Inflammatory Challenge
Authors: Rajan Neena , Stetson Nathaniel , Razzano Passquale , Levine Mitchell , Grande Daniel , Chahine Nadeen
Published: July 2013

Human intervertebral disc (IVD) degeneration is accompanied by elevated levels of pro-inflammatory cytokines, particularly IL-1β and TNF-α [1–3]. Cytokine secretion by disc cells increases catabolic breakdown of the tissue, resulting in a positive feedback of disc integrity loss and further inflammation [4–6]. A recent study by our group has shown that severity of degeneration in an injury model can influence the therapeutic effect of cell based repair, such as treatment with mesenchymal stem cells (MSCs) [7]. The goal of this study is to measure the response of MSCs to inflammatory challenge, and to compare this response to that of differentiated disc cells from the nucleus pulposus (NP), annulus fibrosis (AF) and end plate (EP). In this study, we investigated the effects of lipopolysaccharide (LPS) on intervertebral disc cells and MSCs viability, pro-inflammatory cytokine expression and extracellular matrix (ECM) expression. LPS is an endotoxin that induces strong immune responses in animal tissue and hence widely used as a pre-clinical model of inflammation. This approach provides an opportunity to study broad aspects of the physiological inflammatory process observed in degenerative disc disease.
Evaluation of Regression Equations for Medial and Lateral Contact Force From Instrumented Knee Implant Data
Authors: Meyer Andrew J. , D’Lima Darryl D. , Banks Scott A. , Coburn James , Harman Melinda , Mikashima Yoshinori , Fregly Benjamin J.
Published: July 2013

The ability to predict medial and lateral contact forces accurately in the knee could be useful for research on neuromuscular coordination, the development of treatments for knee osteoarthritis, and the design of knee replacements with improved durability and functionality. To improve their ability to predict medial and lateral contact forces, researchers have recently developed knee implants capable of measuring four [1] or six [2] in vivo loads applied to the tibia. These implants provide data that is useful for validating in vivo knee load predictions from computational models. A difficulty in using these experimental measurements is translating them into clinically significant measurements, i.e. medial and lateral contact force. A simple and quick method for finding these contact forces from the experimental implant data would be ideal.
Characterization of Nanoparticle Distribution in Microcirculation Through a Microfluidics Device
Authors: Thomas Antony , Tan Jifu , Perry Susan , Liu Yaling
Published: July 2013

Various methods of targeted nano drug delivery have been developed in recent years to reduce side effects, toxicity, and lower drug doses [1]. The use of nanoparticles in drug delivery provides advantages in drug targeting, delivery and release along with serving in diagnosis and therapy [2]. Higher percentage of nanoparticle drug is uptaken by the target cells while larger drug particles are easily cleaned off by the human body. Nanoparticles also have large surface to volume ratio, which aids in attachment of many functional groups and thereby enhances targeting.
Dual-Joint Modeling for Estimation of Total Knee Replacement Contact Forces During Locomotion
Authors: Hast Michael W. , Piazza Stephen J.
Published: July 2013

Knowledge of implant loading is critical to improving component designs, surgical techniques, and rehabilitation protocols so that joint replacement life is extended postoperative function is optimized. Determination of the forces applied to joint replacement components during human movement is a challenging goal, however, that is not readily met through experimental methods. Instrumented implants do permit direct measurement of implant loads [1], but instrumented implants do not give a complete characterization of the contact mechanics nor are they practical for incorporation into the implant design cycle.
Design of Tissue-Engineered Leaflet Shape for the Ovine Pulmonary Valve Single Leaflet Replacement Surgery
Authors: Fan Rong , Hobson Christopher M. , Bayoumi Ahmed , Mayer John E. , Wagner William R. , Sacks Michael S.
Published: July 2013

Pulmonary valve (PV) replacement surgery is a treatment option for patients with a congenitally defective pulmonary outflow track. A tissue engineered pulmonary valve (TEPV) is a potential approach to serve as a replacement pediatric heart valve that has the potential for somatic growth. The single leaflet replacement surgical model can assist in assessing candidate biomaterials responses to in-vivo function. However, an empirically determined unloaded leaflet shape may result in abnormal valve function due to incomplete coaptation of leaflets and asymmetric stress distributions. Thus, to determine the final deformed shape of an engineered scaffold replacement PV leaflet under transvalvular pressure the following key factors must be determined: the scaffold anisotropic mechanical properties, optimal thickness, and the exact initial leaflet shape. We have used electrospun poly (ester urethane) ureas (ES-PEUU) scaffolds since they exhibit mechanical properties very similar to the native PV [1]. In this work we present a design framework of the optimal leaflet shape determination utilizing a single sheet of ES-PEUU for single leaflet replacement surgery via finite element (FE) simulation. The mechanical properties of ES-PEUU scaffold for leaflet replacement were obtained from biaxial in-plane tension and three-point bending flexural deformation experiments. Generalized Fung-type hyperelastic constitutive model [2] was implemented into a commercial FE software package to simulate the mechanical behavior of ES-PEUU scaffolds. By perturbing the initial shape of leaflet and simulating its quasi-static deformation under PV diastolic loading, the optimal shape of unloaded leaflet can be determined by comparing the deformed shape of leaflet obtained from FE simulation of TEPV with the one from microCT scan of a native ovine PV.
Nonlinear Vocal Fold Dynamics in a Two-Mass Model of Speech Arising From Asymmetric Intraglottal Flow
Authors: Erath Byron D. , Zañartu Matías , Peterson Sean D. , Plesniak Michael W.
Published: July 2013

Voiced speech is initiated as air is expelled from the lungs and passes through the vocal tract inciting self-sustained oscillations of the vocal folds. While various approaches exist for investigating both normal and pathological speech, the relative inaccessibility of the vocal folds make multi-mass speech models an attractive alternative. Their behavior has been benchmarked with excised larynx experiments, and they have been used as analysis tools for both normal and disordered speech, including investigations of paralysis, vocal tremor, and breathiness. However, during pathological speech, vocal fold motion is often unstructured, resulting in chaotic motion and a wealth of nonlinear phenomena. Unfortunately, current methodologies for multi-mass speech models are unable to replicate the nonlinear vocal fold behavior that often occurs in physiological diseased voice for realistic values of subglottal pressure.
Coupled-Oscillator Model of Suspended Load Locomotion: Predictions of Stability Gains and Metabolic Drop
Authors: Ackerman Jeffrey , Seipel Justin
Published: July 2013

When humans and animals carry load, there is an increase in the metabolic cost of locomotion proportional to the load; this is reduced when the load is elastically coupled to the load carrier [1]. There are existing paradigms in biomechanics that demonstrate this concept, such as the modern horse jockey riding style, the Suspended Load Ergonomic Backpack, and carrying loads with springy poles [1–3]. For example, the Suspended Load Ergonomic Backpack is designed to suspend a load with compliant springs that elastically decouple the motion of the load from the motion of the wearer [2]. It has been shown to reduce the peak forces and reduce the metabolic cost of locomotion compared to a standard backpack [2].
Assessment of Right Ventricular Inefficiency Using Energy Transfer Ratio in Repaired Tetralogy of Fallot
Authors: Lee Namheon , Das Ashish , Gottliebson William M. , Banerjee Rupak K.
Published: July 2013

Pulmonary insufficiency (PI) induces pulmonary regurgitation and often leads to right ventricular (RV) enlargement and RV pressure overloading in repaired Tetralogy of Fallot (rTOF) patients. The appropriate timing of surgical treatments to renormalize RV function remains uncertain due to lack of suitable clinical diagnostic parameters. An energy transfer ratio (eMPA) between the net energy (Enet) transferred at main pulmonary artery (MPA) from RV and stroke work (SW) by RV was calculated using RV volume and pressure data for subjects in two study groups: the rTOF patient group (n = 7) and the control group (n = 7). Statistical analysis was performed to determine the difference of eMPA between the two groups. The mean eMPA for rTOF patients (0.64) was significantly lower (60.2%, p<0.05) than that of controls (1.61).
Development of a Computational Model of Lymphangions in Series: A Parameter Sensitivity Analysis
Authors: Weimer Jon , Moore James E. , Bertram Christopher D. , Richardson Will , Placette Beth Ann
Published: July 2013

The lymphatic system plays a vital role in the body to maintain normal health. The lymphatics are responsible for fluid and protein balance, as they transport approximately 3.6 liters/day of fluid from the interstitial spaces to the venous circulation. Throughout this transfer process, both positive and negative events can occur. Undesirable pathogens are typically destroyed in lymph nodes, but since it serves as the primary transport mechanism for the immune system, it is also involved in the spread of pathogens such as cancer cells.
Synthesis and Cytotoxicity Analysis of Carbon Nanohorn-Quantum Dot Complexes
Authors: Zimmermann Kristen A. , Zhang Jianfei , Dorn Harry , Rylander Christopher , Rylander Marissa Nichole
Published: July 2013

Carbon nanoparticles have the potential to significantly impact the medical field over the next decade. Currently, carbon nanoparticles are being studied for a myriad of applications, including drug delivery, selective laser therapy, imaging, and biosensing. The most common type of carbon particles being investigated are carbon nanotubes (CNTs). CNTs are attractive materials for medical applications because of their physical properties and the ease with which they can be surface modified; however, there is a great deal of controversy over their possible toxicity. A more novel type of CNT that was discovered in 1999 by Iijima et al. is the carbon nanohorn [1]. Individual single-walled nanohorns (SWNHs) are single graphene sheets that roll into a conical open ended structure. The open ends of these cones are then attracted to one another through van der Waals interactions and form a flower-like final structure [2]. SWNHs are more favorable for medical applications because they are produced without the use of metal catalysts abating the concern of toxicity associated with CNTs.
Computational Models and Digital Image Analysis of Carbon Nanotube Mediated Laser Cancer Therapy
Authors: Whitney Jon , Sarkar Saugata , Ding Xuanfeng , Singh Ravi , Burke Andrew , Torti Suzy , Rylander Marissa Nichole
Published: July 2013

Laser-based photothermal therapy can provide a minimally invasive treatment alternative to surgical resection of tumors. The selectivity and effectiveness of laser therapy can be greatly enhanced when photo-absorbing nanoparticles such as multi-walled carbon nanotubes (MWNTs) are introduced into the tissue [1,2]. The effectiveness of nanoparticle enhanced laser treatment can be determined through a combined approach using experimental measurement and computational models. This approach allows ideal laser parameters (e.g. irradiance, pulse duration) and nanoparticle properties (e.g. concentration and delivery method) to be selected to maximize treatment efficacy. We developed a computational model to predict the temperature response of tissue representative phantoms and in vivo murine renal cancer (RENCA) kidney tumors to MWNTs used in combination with external laser irradiation. The accuracy of the computational model prediction of temperature was verified by comparing with experimental measurements of temperature using magnetic resonance thermometry (MRTI). In addition, an image analysis technique is introduced for measuring the spatial viability of cancer cells suspended in tissue phantoms following nanoparticle enhanced laser therapy and correlating cell viability with thermal exposure. Spatial viability and thermal measurements are combined to predict cell death as a function of temperature in tissue phantoms.
Digital Microfluidic Platform for 3-D Tissue Based High Throughput Screening
Authors: George Subin M. , Moon Hyejin
Published: July 2013

Pharmaceutical drug development requires exhaustive testing of potential drugs in before animal and human clinical trials. Only one in ten drugs entering clinical trials receive the final approval. Most drugs fail in later stages due to lack of efficacy or toxicity which are discovered later on, after having cleared in vitro trials [1]. This highlights the need for improved laboratory testing methods to screen out failure candidates. It should be noted that 3-dimensional (3D) tissue constructs provide a better environment to mimic physiological processes as compared to conventional 2-dimensional (2D) cell based testing systems [2]
Design of Efficient Electroosmotic Micromixer
Authors: Panta Yogendra M. , Adhikari Param C.
Published: July 2013

Micro-bio/chemical applications in a μTAS (Micro Total Analysis Systems) require rapid and uniform mixing of a number of fluid streams that carries bio/chemical species in the solution. An electro osmotic mixer from COMSOL model library is taken as a main model from which other alterations are designed for optimization. The circular, square and elliptical mixers were modeled to see the variation in the mixing. We analyzed the mixing process by varying the mixing shape, concentration, mixing channel width and electrode pairs. Concentration variance at the outlet over time was studied to determine the extent of mixing.
In Vitro Investigation of the Effect of Flow Pulsatility on Power Loss in the Total Cavopulmonary Connection
Authors: Tang Elaine , Khiabani Reza H. , Haggerty Christopher M. , Yoganathan Ajit P.
Published: July 2013

Total Cavopulmonary Connection (TCPC) is the most common surgical palliation for single ventricle heart defects. In such connections, venae cavae are connected to the pulmonary arteries, bypassing the right ventricle. The patient-specific anatomical complexity makes characterization and optimization of the fluid mechanics a unique challenge.
On smoothing articulatory trajectories obtained from Gaussian mixture model based acoustic-to-articulatory inversion
Authors: Ghosh Prasanta K. , Narayanan Shrikanth S.
Published: July 2013

It is well-known that the performance of acoustic-to-articulatory inversion improves by smoothing the articulatory trajectories estimated using Gaussian mixture model (GMM) mapping (denoted by GMM + Smoothing). GMM + Smoothing also provides similar performance with GMM mapping using dynamic features, which integrates smoothing directly in the mapping criterion. Due to the separation between smoothing and mapping, what objective criterion GMM + Smoothing optimizes remains unclear. In this work a new integrated smoothness criterion, the smoothed-GMM (SGMM), is proposed. GMM + Smoothing is shown, both analytically and experimentally, to be identical to the asymptotic solution of SGMM suggesting GMM + Smoothing to be a near optimal solution of SGMM.
Changes in Amyloid-β and Tau in the Cerebrospinal Fluid of Transgenic Mice Overexpressing Amyloid Precursor Protein
Authors: Maia Luis F. , Kaeser Stephan A. , Reichwald Julia , Hruscha Michael , Martus Peter , Staufenbiel Matthias , Jucker Mathias
Published: July 2013

Changes in Aβ and Tau in the CSF of APP transgenic mice mirror the temporal sequence and magnitude of changes in these proteins in the CSF of Alzheimer’s disease patients.
Vector Decoys Trick the Immune Response
Authors: VandenDriessche Thierry , Chuah Marinee K.
Published: July 2013

Humoral immunity to adeno-associated viral vectors can be overcome by using empty capsid mutant “decoys” for preexisting antibodies (Mingozzi
et al
., this issue).
Incidental Swimming with Millstones
Authors: Kingsmore Stephen F.
Published: July 2013

The medical genomics community needs carefully considered guidelines for the reporting of incidental findings.
Two Drugs Are Better than One—Modeling Drug Combinations in Cancer Therapy
Authors: Callahan Margaret K.
Published: July 2013

Human melanoma tumor samples underlie a mathematical model that predicts responses to combinations of targeted drugs.
Stealth Attack by the Gut Microbiota
Authors: Eid Tore
Published: July 2013

Perturbations in the normal bacterial flora of the gut contribute to hepatocellular carcinoma in obese mice.
Can Antacids Affect the Heart?
Authors: Tonelli Adriano R.
Published: July 2013

Common antacid drugs raise the concentration of asymmetric dimethylarginine, a molecule that potentially increases cardiovascular risk.
Influenza Viruses: Breaking All the Rules
Authors: Taubenberger Jeffery K. , Morens David M.
Published: July 2013

Influenza A viruses (IAV) are significant pathogens able to repeatedly switch hosts to infect multiple avian and mammalian species, including humans. The unpredictability of IAV evolution and interspecies movement creates continual public health challenges, such as the emergence of the 2009 pandemic H1N1 virus from swine, as well as pandemic threats from the ongoing H5N1 and the recent H7N9 epizootics. In the last decade there has been increased concern about the “dual use” nature of microbiology, and a set of guidelines covering “dual use research of concern” includes seven categories of potentially problematic scientific experiments. In this Perspective, we consider how in nature IAV continually undergo “dual use experiments” as a matter of evolution and selection, and we conclude that studying these properties of IAV is critical for mitigating and preventing future epidemics and pandemics.
6: Seismicity, crustal structure, and intraplate tectonics of the interior of the western Cordillera
Authors: Smith Robert B.
Published: July 2013

Seismicity, fault-plane solutions, and Cenozoic geology are used to infer contemporary west to northwest extension and components of lateral slip between subplates of the western North American plate. Seismicity of the western interior of the Cordillera is characterized by earthquakes that occur in broad zones, up to 150 km wide, in the Nevada and the Intermountain seismic zones. Epicenters are scattered and when accurately located many do not coincide with mapped faults. Focal depths are shallow and seldom exceed 20 km. Secondary seismicity occurs around the margins of the Colorado Plateau, in central Idaho, and in eastern Oregon and Washington. The contemporary strain pattern of the Western United States, as interpreted from fault-plane solutions, suggests that three intraplate lithospheric blocks—the Sierra Nevada, the Great Basin-High Lava Plains, and the Northern Rocky Mountains-Columbia Plateau are moving west to northwest as “slivers” between the obliquely converging Pacific and North American plates. Intraplate extension within the Great Basin is primarily accommodated by north-south normal faulting in north-central Nevada and along the Wasatch Front, but significant components of strike-slip faulting occur along active seismic zones in southwestern Nevada and along the northern Intermountain seismic belt in Montana.

A thin crust, ~25 km, characterizes the east margin of the Great Basin, with average Pn-velocities of ~7.5 km /s. A crustal low-velocity layer, at 5 to 15 km depth, coincides with the eastern margin of the Great Basin. A thin crust, with an apparent Pn-velocity of ~7.7 km /s, occurs on the northwest margin of the Great Basin and beneath parts of the Oregon-High Lava Plains. The central part of the Great Basin has a thicker crust, ~30 km, and higher Pn-velocities, 7.7 to 7.9 km /s. The Colorado Plateau and the Rocky Mountains have thicker crusts, 40 to 50 km, and Pn-velocities of ~7.8 km/s.

An upper-mantle diapir or an upwelling thermal mechanism, facilitated by stress relaxation above the now-truncated Farallon subducting plate, is postulated to have uplifted, extended, and heated the crust of the Great Basin beginning at ~20 m.y. Late Cenozoic centers of volcanism appear to have progressed outward from a northern Great Basin thermal center in two divergent directions—northwesterly along a combined extensional-strike-slip zone of deformation in the High Lava Plains of southeastern Oregon and northeasterly along an extensional zone marked by the Snake River Plain. Lithospheric heating is thought to have produced a broad uplift of the Great Basin with concomitant crustal thinning and diminishing of upper-mantle Pn-velocities. The thermal mechanisms are hypothesized to have produced laterally divergent mantle flow to form symmetric zones of crustal thinning and low Pn-velocities that presently mark the east and west margins of the Great Basin.
Comparing hormone therapy effects in two RCTs and two large observational studies that used similar methods for comprehensive data collection and outcome assessment
Authors: Hartz Arthur , He Tao , Wallace Robert , Powers John
Published: July 2013

Objectives

Prospective observational studies (OSs) that collect adequate information about confounders can validly assess treatment consequences. However, what constitutes adequate information is unknown. This study investigated whether the extensive information collected by the Women's Health Initiative (WHI) in two OSs and two randomised controlled trials (RCTs) was adequate.

Design

Secondary analysis of WHI data. Cox regression was used to select from all baseline risk factors those that best predicted outcome. Cox regression that included these risk factors was used for two types of analyses: (1) comparing RCT and OS assessments of the effects of hormone therapy on outcome for participants with specific characteristics and (2) evaluating whether adjustment for measured confounders could eliminate outcome differences among datasets.

Setting

The WHI included more than 800 baseline risk factors and outcomes during a median follow-up of 8 years.

Participants

151 870 postmenopausal women ages 50–79.

Primary and secondary outcome measures

Myocardial infarction and stroke.

Results

RCT and OS results differed for the association of hormone therapy with outcome after adjusting for confounding factors and stratifying on factors that were hypothesised to modulate the effects of hormone therapy (eg, age and time since menopause) or that empirically modulated the effects of hormone therapy in this dataset (eg, blood pressure, previous coronary revascularisation and private medical insurance). Some of the four WHI datasets had significantly worse outcomes than others even after adjusting for risk and stratifying by type of hormone therapy, for example, the risk-adjusted HR for myocardial infarction was 1.37 (p<0.0001) in an RCT placebo group compared with an OS group not taking hormone therapy.

Conclusions

Apparently the WHI did not collect sufficient information to give reliable assessments of treatment effects. If the WHI did not collect sufficient data, it is likely that few OSs collect sufficient information.
Angiotensin II downregulates ACE2-mediated enhancement of MMP-2 activity in human cardiofibroblasts
Authors: Kuan Tang-Ching , Chen Mu-Yuan , Liao Yan-Chiou , Ko Li , Hong Yi-Han , Yen Chun-Yi , Hsieh Wen-Yeh , Cheng Kun-Shan , Wu Chien-Liang , Lin Chih-Sheng
Published: July 2013

Angiotensin converting enzyme II (ACE2) is a component of the renin-angiotensin system (RAS) that negatively regulates angiotensin II (Ang II). Ang II, in turn, affects the expression of matrix metalloproteinases (MMPs) to induce heart remodeling. The specific mechanisms by which ACE2 regulates MMP-2, however, remain unclear. The aim of this study was to investigate the regulatory relationships between Ang II, ACE2, and MMP-2. ACE2 expression was upregulated and downregulated in human cardiofibroblasts (HCFs) by lentiviral infection. Effects on MMP-2 activity, shed ACE2 activity, extracellular signal-regulated kinase (ERK) signaling pathway, and ADAM metallopeptidase domain 17 (ADAM17) expression were assessed. ACE2 increased MMP-2 activity, and Ang II inhibited this effect through the Ang II type-1 receptor (AT1R) and ERK1/2 signaling pathway. Ang II also reduced the effect of ACE2 on ERK1/2 levels, the activity of shed ACE2, and adam17 expression in HCFs. Additionally, these Ang II-mediated reductions could be attenuated by AT1R antagonist valsartan. In conclusion, these data help to clarify how ACE2 and Ang II interact to regulate MMP-2 and control tissue remodeling in heart disease.
Re-mobilization of pile shaft friction after an earthquake
Authors: Stringer M.E. , Madabhushi S.P.G.
Published: July 2013

During strong earthquakes, significant excess pore pressures can develop in saturated soils. After shaking ceases, the dissipation of these pressures can cause significant soil settlement, creating downward-acting frictional loads on piled foundations. Additionally, if the piles do not support the full axial load at the end of shaking, then the proportion of the superstructure’s vertical loading carried by the piles may change as a result of the soil settlement, further altering the axial load distribution on piles as the soil consolidates. In this paper, the effect of hydraulic conductivity and initial post-shaking pile head loading is investigated in terms of the changing axial load distribution and settlement responses. The investigation is carried out by considering the results from four dynamic centrifuge experiments in which a 2 × 2 pile group was embedded in a two-layer profile and subjected to strong shaking. It is found that large contrasts in hydraulic conductivity between the two layers of the soil model affected both the pile group settlements and axial load distribution. Both these results stem from the differences in excess pore pressure dissipation, part of which took place very rapidly when the underlying soil layer had a large hydraulic conductivity.
Anti-mycobacterial activities of copper(II) salicylaldimine complexes derived from long-chain aliphatic amines
Authors: Patterson Alyssa E. , Bowes Eric G. , Bos Allyson , O’Neill Taryn , Li Haoxin , Flewelling Andrew , Vogels Christopher M. , Decken Andreas , Gray Christopher A. , Westcott Stephen A.
Published: July 2013

Twelve copper(II) Schiff base complexes derived from lipophilic amines have been prepared using either salicylaldehyde or ortho-vanillin via a microwave-assisted reaction. All complexes have been obtained elementally pure and an X-ray diffraction of an isopentyl derivative has confirmed the structure of these compounds. All complexes showed a promising degree of anti-mycobacterial activity against Mycobacterium tuberculosis, where activity seemed to increase with an increase in the length of the aliphatic chain.
Potential climate change impacts on temperate forest ecosystem processes
Authors: Peters Emily B. , Wythers Kirk R. , Zhang Shuxia , Bradford John B. , Reich Peter B.
Published: July 2013

Large changes in atmospheric CO2, temperature, and precipitation are predicted by 2100, yet the long-term consequences for carbon (C), water, and nitrogen (N) cycling in forests are poorly understood. We applied the PnET-CN ecosystem model to compare the long-term effects of changing climate and atmospheric CO2 on productivity, evapotranspiration, runoff, and net nitrogen mineralization in current Great Lakes forest types. We used two statistically downscaled climate projections, PCM B1 (warmer and wetter) and GFDL A1FI (hotter and drier), to represent two potential future climate and atmospheric CO2 scenarios. To separate the effects of climate and CO2, we ran PnET-CN including and excluding the CO2 routine. Our results suggest that, with rising CO2 and without changes in forest type, average regional productivity could increase from 67% to 142%, changes in evapotranspiration could range from –3% to +6%, runoff could increase from 2% to 22%, and net N mineralization could increase 10% to 12%. Ecosystem responses varied geographically and by forest type. Increased productivity was almost entirely driven by CO2 fertilization effects, rather than by temperature or precipitation (model runs holding CO2 constant showed stable or declining productivity). The relative importance of edaphic and climatic spatial drivers of productivity varied over time, suggesting that productivity in Great Lakes forests may switch from being temperature- to water-limited by the end of the century.
Changes in white pine blister rust infection and mortality in limber pine over time
Authors: Smith Cyndi M. , Langor David W. , Myrholm Colin , Weber Jim , Gillies Cameron , Stuart-Smith Jon
Published: July 2013

Limber pine (Pinus flexilis E. James) is under threat from white pine blister rust (WPBR), mountain pine beetle, drought, and fire suppression across its range in western North America. In 2003–2004, we established 85 plots to assess the mortality and incidence of WPBR on limber pine, and remeasured them in 2009. Infection was evident in 74% of the plots in 2003–2004 and 88% of the plots in 2009. The proportion of dead trees increased from 32% in 2003–2004 to 35% in 2009. The percentage of live trees infected increased from 33% in 2003–2004 to 43% in 2009. Mean live limber pine basal area in 2009 ranged from 0.03 to 77.8 m2/ha per plot. Twenty (24%) of the plots had no seedlings in the first measurement, but only 15% in the second measurement. Seedling infection was low (8% in 2003–2004 and 4% in 2009). In 12 plots that were measured three times, mortality increased from 30% of all trees in 1996 to 50% in 2003, then decreased to 46% in 2009. Infection decreased from 73% of live trees in 1996 to 46% in 2003, then increased to 66% in 2009. High mortality and infection levels suggest that the long-term persistence of many limber pine populations in the southern part of the study area are in jeopardy, and continued monitoring is needed to assist with management decisions.
Fire-history implications of fire scarring
Authors: Baker William L. , Dugan Alexa J.
Published: July 2013

Fire scars are widely used to reconstruct fire history, yet patterns of scarring are poorly understood, hampering effective sampling and analysis. Factors that influence the probability a tree will receive a scar (SP) and the fraction of trees that scar (SF) are little studied. We analyzed scarring in 16 fires in ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) forests in northern Arizona. SP was significantly related to char height, presence of a preceding scar, tree diameter, and years since a preceding fire. Mean SF was 0.375, but varied from 0.121 to 0.728, with SF significantly higher with higher mean char height, larger scar dimensions, higher fire severity, larger tree diameter, and where no preceding fire had burned within 30 years. The expected healing times exceeded 55 years for 33% of scars and 100 years for 11% of scars. Scars with a preceding scar were 38% larger than new scars, with expected healing about 20–25 years longer. Scars were clustered, particularly at scales from >20 to >40 m. Scar directions generally aligned with fire-spread directions, which were complex. Variability in SF complicates fire-history methods that use fire counts rather then area burned. Methods that account for spatial and temporal variability in the abundance of evidence are needed.
Development of a genetic linkage map for Sharon goatgrass (Aegilops sharonensis) and mapping of a leaf rust resistance gene
Authors: Olivera P.D. , Kilian A. , Wenzl P. , Steffenson B.J.
Published: July 2013

Aegilops sharonensis (Sharon goatgrass), a diploid wheat relative, is known to be a rich source of disease resistance genes for wheat improvement. To facilitate the transfer of these genes into wheat, information on their chromosomal location is important. A genetic linkage map of Ae. sharonensis was constructed based on 179 F2plants derived from a cross between accessions resistant (1644) and susceptible (1193) to wheat leaf rust. The linkage map was based on 389 markers (377 Diversity Arrays Technology (DArT) and 12 simple sequence repeat (SSR) loci) and was comprised of 10 linkage groups, ranging from 2.3 to 124.6 cM. The total genetic length of the map was 818.0 cM, with an average interval distance between markers of 3.63 cM. Based on the chromosomal location of 115 markers previously mapped in wheat, the four linkage groups of A, B, C, and E were assigned to Ae. sharonensis (Ssh) and homoeologous wheat chromosomes 6, 1, 3, and 2. The single dominant gene (designated LrAeSh1644) conferring resistance to leaf rust race THBJ in accession 1644 was positioned on linkage group A (chromosome 6Ssh) and was flanked by DArT markers wpt-9881 (at 1.9 cM distal from the gene) and wpt-6925 (4.5 cM proximal). This study clearly demonstrates the utility of DArT for genotyping uncharacterized species and tagging resistance genes where pertinent genomic information is lacking.
ASYMPTOTICS OF LARGE EIGENVALUES FOR A CLASS OF BAND MATRICES
Authors: BOUTET DE MONVEL ANNE , JANAS JAN , ZIELINSKI LECH
Published: July 2013

We investigate the asymptotic behavior of large eigenvalues for a class of finite difference self-adjoint operators with compact resolvent in l2.
DYNAMIC PULSE INTEGRATING CIRCUIT FOR INFRARED RECEIVERS
Authors: SHI LING-FENG , ZENG AI-QIN , LI QIN-QIN , CHENG LI-YE , LAI XIN-QUAN
Published: July 2013

In this paper, a frequency-tunable dynamic pulse integrating circuit for infrared receivers is presented. The proposed circuits possess many advantages, such as high sensitivity, high immunity against disturbances, simple structure, and so on. This integrator not only defines a minimum time for the burst length and a minimum time between the bursts, but also achieves the same minimum number of pulses in different frequencies. The frequency-tunable dynamic pulse integrator is a combined structure of the center frequency modulation and a new type of pulse integrator. The center frequency modulation is implemented by using zener zap anti-fuse trim and a second-order band-pass filter (BPF) with bipolar operational transconductance amplifier (OTA) cell. The integrator also describes the characteristics of variable-error tolerance to prevent the output envelope error due to the lack of individual pulses. The results of simulation are shown that the center frequency is available from 33 to 40 kHz and 56 kHz in typical application by Cadence respectively. Moreover, the minimum burst length is 10 pulses and minimum bursts gap time is 14 pulses in typical application.
IMPLEMENTING LOW-COST FAULT TOLERANCE VIA HYBRID SYNCHRONOUS/ASYNCHRONOUS CHECKS
Authors: LI JIANLI , TAN QINGPING , TAN LANFANG
Published: July 2013

As semiconductor technologies scale down to deep sub-micron dimensions, transient faults will soon become a critical reliability concern. Due to their prohibitive costs, traditional high-end solutions are unacceptable for the mainstream commodity market. This paper presents FTPIPE, a hybrid software/hardware solution, which provides sufficient fault coverage with affordable overhead for single-threaded programs running on commodity systems. Leveraging existing exception mechanisms with minor modifications to handle exception-causing faults, FTPIPE focuses on tolerating silent data corruptions by using compile-time analysis and performing selective instruction replication in a modern superscalar pipeline extended with minimal hardware overhead. Unlike existing instruction replication-based solutions, which detect faults by synchronous checks, the FTPIPE platform has exploited a novel hybrid synchronous/asynchronous check method for the replicated instructions. In this manner, better performance can be obtained without degradation of fault coverage. By synchronous checks, the validation of the result of a replicated instruction must be finished before it is committed, whereas such a guarantee is not required by an asynchronous check. Evaluation using a set of nine programs from the Mibench benchmark suite demonstrates that FTPIPE can tolerate 89.8% of transient faults under a modest performance overhead of 20.1%.
GENERATION OF THIRD-ORDER QUADRATURE OSCILLATOR CIRCUITS USING NAM EXPANSION
Authors: SOLIMAN AHMED M.
Published: July 2013

A systematic synthesis procedure for generating third-order grounded passive element quadrature oscillators is given. The synthesis procedure is based on using nodal admittance matrix (NAM) expansion applied to the Y matrix of a recently reported three Op Amp third-order oscillator circuit. Four new circuits using current conveyors (CCII) are reported. In addition four more new circuits using inverting current conveyors (ICCII) are also given. Many more quadrature third-order oscillator circuits using combinations of CCII and ICCII can be obtained. Simulation results demonstrating the practicality of one of the generated circuits are included.
STABILITY AND NONLINEAR DYNAMIC ANALYSES OF BEAM WITH PIEZOELECTRIC ACTUATOR AND SENSOR BASED ON HIGHER-ORDER MULTIPLE SCALES METHODS
Authors: RECHDAOUI M. S. , AZRAR L.
Published: July 2013

Higher-order multiple scales methods have been developed for a strong nonlinear differential equation modeling the nonlinear transverse dynamic behavior of piezoelectric–elastic–piezoelectric sandwich beams. The proportional and derivative potential feedback controls via sensor and actuator layers are used. Two higher-orders multiple scales methods are developed leading to accurate approximate time-response and frequency and phase-amplitude relationships. As the classical multiple scales method disregards the quadratic nonlinear terms, the developed higher-order multiple scales methods overcame this drawback and lead to more accurate results. Static and dynamic stability criteria are elaborated and tested. Critical bifurcation points and peak amplitudes are characterized in accordance with the excitation amplitude and the feedback parameters.