bluuebunny/crossref_metadata_2025 huggingface dataset:
Machine Learning Techniques for the Assessment of AAA Rupture Risk
Authors: Shum Judy , Di Martino Elena S. , Muluk Satish C. , Finol Ender A.
Published: July 2013

Recent clinical studies have shown that the maximum transverse diameter of an abdominal aortic aneurysm (AAA) alone, or in combination with its expansion rate are not entirely reliable indicators of rupture potential. We hypothesize that AAA shape, size, and wall thickness may be related to rupture risk and can be deciding factors in the clinical management of the disease. A non-invasive, image-based evaluation of AAA size and geometry was implemented using an in-house code (AAAVASC v1.0, Carnegie Mellon University) on a retrospective study of 88 subjects. The contrast enhanced, computed tomography (CT) scans of 44 patients who suffered AAA rupture within 1 month of the scan were compared to those of 44 patients who received elective repair. The images were segmented and three-dimensional models were generated. Twenty-eight geometry-based indices were calculated to characterize the size and shape of each AAA and estimate regional variations in wall thickness. A multivariate analysis of variance was performed for all indices comparing the ruptured and non-ruptured data sets to determine which indices were statistically significant. A classification model was created using a J48 decision tree algorithm and its performance was assessed using 10-fold cross validation. The model correctly classified eighty-six data sets and had an average prediction accuracy of 74% (κ = 0.69). Such a decision model can be used in a clinical setting to assess the risk of AAA rupture with minimal user intervention.
Importance of Protein Denaturation to Thermochemical Ablation of Liver Tumors
Authors: Mori Shoji , Aravalli Rajagopal , Choi Jeunghwan , Cressman Erik , Bischof John
Published: July 2013

Solid tumors in the liver such as hepatocellular carcinoma, often are not amenable to chemotherapy or surgical therapies. Local “ablation” methods including thermal and chemical ablation are therefore options for treatment. Hyperthermic ablation methods (RF, microwave, HIFU and laser) can potentially accomplish treatment in a single session but are considerably more costly than chemicals. It was therefore of interest to investigate if a known protein denaturant such as urea would destroy liver tumors. Further, we wished to assess whether this destruction occurs by protein denaturation mechanisms similar to hyperthermic destruction. Specifically, Lepock showed that hyperthermic cell destruction occurs for many cells when overall protein denaturation is greater than 5% (i.e. survival drops from 95% to 5% beyond this range). In this study we report on the cytotoxicity of urea on human hepatoma HuH-7. We then quantify the amount of cellular protein denaturation associated with cytotoxicity and show that protein denaturation in excess of 5% of total protein must occur in order for significant cell killing.
Dynamics of Stretch-Induced Stress Fiber Remodeling in 3D Cell Culture
Authors: Lee Sheng-Lin , Nekouzadeh Ali , Pryse Kenneth M. , Elson Elliot L. , Genin Guy M.
Published: July 2013

The responses of living cells to mechanical stimuli are believed to underlie diseases such as fibrotic cardiomyopathy [1] and asthma [2]. Emerging evidence suggests that mechanical signals transduced through the actin cytoskeleton and its connections to the extracellular matrix (ECM) have important effects on cell physiology and tissue development [13]. Understanding the responses of cells in realistic mechanical environments to mechanical stimuli is therefore of great importance to understanding development and disease.
Delivery of Active FGF-2 From Mechanically-Stable Biological Nanofibers Accelerates Cell Ingress Into Multifiber Composites
Authors: Kluge Jonathan A. , Pampati Rudra A. , Schenker Mara L. , Zhou Daniel J. , Esterhai John E. , Kaplan David L. , Mauck Robert L.
Published: July 2013

Fibrocartilaginous tissues such as the meniscus and annulus fibrosus serve critical load-bearing roles, relying on arrays of highly organized collagen fibers to resist tensile loads [1]. As these specialized structures are often injured, there exists great demand for engineered tissues for repair or replacement. Cell-laden aligned nanofibrous scaffolds formed from poly(ε-caprolactone) (PCL) have shown promise in achieving tissuelike mechanical and biochemical properties and can direct cellular and matrix organization in vitro [2]. A current limitation of nanofibrous scaffolds, however, is a slow rate of cellular infiltration, particularly in thick scaffolds. To address this, dynamic composite nanofibrous scaffolds have been fabricated via multi-fiber spinning [3], which can offer tunable modes of degradation depending on the polymer sources. For example, water-soluble polyethylene oxide (PEO) fibers can be co-spun with PCL to improve porosity and hasten cell ingress [4]. Incorporation of additional tunable and bioactive polymer sources may add greater versatility to these composite systems. For example, aqueous-based silk fibroin can be used as a slow-degrading, mechanically strong composite fiber component [5] into which active biologic factors (drugs, growth factors) can be incorporated [6]. Variably-degradable silk fibers can be formed by modulating post-spinning treatments, and protein release kinetics can likewise be manipulated by the physical crosslinking method [7]. We hypothesized that incorporation of robust and tunable silk protein-based fibers into a composite of slow-degrading synthetic fibers would provide mechanical function while delivering active biologic factors to expedite cell proliferation and encourage more rapid construct colonization. To test this hypothesis, we characterized the release kinetics of recombinant FGF-2 from silk fibers and its bioactivity in vitro and in a rat subcutaneous implant model.
A Structural Constitutive Model for Right Ventricular Myocardium
Authors: Valdez-Jasso Daniela , Simon Marc A. , Sacks Michael S.
Published: July 2013

Although right-ventricular (RV) function is an important determinant of cardio-pulmonary performance in health and disease, RV myocardium biomechanical function has received little attention. In particular, no multiaxial data of the full-thickness RV have been reported for the passive or active myocardial states, for either normal or pathological conditions. Since an understanding of tissue-level biomechanical behavior is integral to connecting cellular behavior to organ-level performance, investigations into the RV myocardial stress-strain relationship are central in providing this link. For example, ventricular wall stress is considered to be a major driver of ventricular remodeling, and thus a better understanding of how wall stress and deformation are linked would provide unique insight into the mechanisms of RV function and ultimately failure in disease. Such knowledge would have direct applicability to improving methods to detect RV dysfunction, predicting response to disease-specific therapies and improving the timing of therapy if or when needed. Here, we present the first report on the multiaxial biomechanical behavior of viable full-thickness right-ventricular free wall (RVFW) myocardium and our initial efforts in developing a structural constitutive model for this remarkable tissue.
Microstructural Changes in Collagen and Elastin and Their Impact on the Mechanics of the Pulmonary Artery in Hypertension
Authors: Lammers Steven , Feyintola Tosin , Hunter Kendall , Gibson Emily , Lei Tim , Kao Phil , Qi H. Jerry , Lanning Craig , Shandas Robin , Stenmark Kurt
Published: July 2013

In pulmonary arteries (PA), mechanical function is largely driven by the underlying microstructure of the structural proteins collagen and elastin, which reside within the extracellular matrix (ECM) of the arterial tissue. It has long been established that much of the mechanical non-linearity associated with arterial tissue is the result of collagen mechanics. Arterial collagen is arranged within the vascular wall as tortuous fibrils with a bulk fiber orientation of roughly helical configuration. When arterial tissue is deformed, these collagen fibers become straightened in the direction of applied load. At some critical deformation, termed the transition stretch (λTrans), collagen fibers begin to carry load, thus significantly altering material stiffness. This in turn gives rise to the non-linear force-stretch (F-λ) response typical of these tissues, Figure 1. We have recently found that λTrans is significantly reduced in the hypoxia-induced pulmonary hypertensive (PH) rat model. We therefore propose that this model constitutes an ideal system to study the effect of collagen microstructure on the mechanics of arterial tissues in response to PH vascular remodeling. We hypothesize that quantitative characterization of collagen microstructure will predict pulmonary artery (PA) λTrans within this model system. By directly relating collagen microstructural changes to bulk tissue mechanics in response to PH-induced vascular remodeling we can better understand how changes in collagen structure impact pulmonary hemodynamic capacitance, a major component of cardiac load and contributing factor to right heart failure.
A Strain Energy-Based Constitutive Model for Continuous-Fiber Tissue Engineered Valved Conduit Tissue
Authors: Eckert Chad E. , Sacks Michael S.
Published: July 2013

Understanding growth and remodeling of extracelluar matrix (ECM) embedded in a scaffold phase is crucial for improving tissue engineering efforts, especially within the context of a mechanically-demanding enviroment to which engineered heart valve tissues (EHVT) are subjected. Our previous modeling efforts at short in vitro timepoints (one to three weeks) [1] illustrated the strong dependency of ECM-scaffold composite mechanical properties on that of the existing continuous scaffold phase. In this work, we build on these efforts by developing a generalized, large-deformation continuum-based model for short timepoint in vitro/in vivo environments and validating it using a ECM-analog system to simulate remodeling tissue. It is our intent to estimate the ECM mechanical quality from the measured scaffold-ECM composite.
A Spring-Mass Model of Locomotion With Full Asymptotic Stability
Authors: Shen Zhuohua , Seipel Justin
Published: July 2013

The concept of passive dynamic walking and running [5] has demonstrated that a simple passive model can represent the dynamics of whole-body human locomotion. Since then, many passive models were developed and studied: [3,1,2,11]. The later developed Spring-Loaded Inverted Pendulum (SLIP) [1, 4, 11, 2] exhibits stable center of mass (CoM) motions just by resetting the landing angle at each touch down. Also, compared to SLIP, a SLIP-like model with simple flight leg control is better at resisting perturbations of the angle of velocity but not the magnitude [11, 2, 7]. Energy conserving models explain much about whole-body locomotion. Recently, there has been investigations of modified spring-mass models capable of greater stability, like that of animals and robots [9, 10, 8, 12]. Inspired by RHex [6], the Clock-Torqued Spring-Loaded Inverted Pendulum (CT-SLIP) model [9] was developed, and has been used to explain the robust stability of animal locomotion [12]. Here we present a model (mechanism) simpler than CT-SLIP called Forced-Damped SLIP (FD-SLIP) that can attain full asymptotically stability of the CoM during locomotion, and is capable of both walking and running motions. The FD-SLIP model, having fewer parameters, is more accessible and easier to analyze for the exploration and discovery of principles of legged locomotion.
Decoupled Stabilization of Spring-Mass Rigid-Body Locomotion
Authors: Hu Huan , Seipel Justin
Published: July 2013

Stable and reliable legged locomotion is critical for humans and humanoid robots. In the study of legged locomotion, simple models consisting of point-mass bodies and massless legs with telescoping actuators have been insightful. Several variants have been used, including the telescoping leg as a general force actuator [1], a simple passive linear or nonlinear spring [2], and a spring in series with a general force actuator [3]. These models serve as analogs that simplify the problem of understanding the mechanics of legged locomotion of real animals. One of defects of these simple models is the representation of the body by a point mass. Hence, trunk stabilization is not addressed. Nevertheless, this is a major problem in human and humanoid locomotion. In this study we propose a novel decoupled strategy to stabilize the trunk. First, we describe how this decoupled strategy works theoretically. Then, we present a case study based on the CT-SLIP model. Finally, we summarize the work and its expected impacts.
Separation Analysis of Breast Cancer Progression Lines Using Contactless Dielectrophoresis
Authors: Rojas Andrea D. , Schmelz Eva M. , Davalos Rafael V.
Published: July 2013

Selective separation and isolation of microparticles or cells based on their biophysical properties has become an essential step in laboratory use [1]. Techniques include field flow fractionation [2], fluorescent and magnetic activated cell sorting [3], laser tweezers [4] and dielectrophoresis [5]. The latter technique uses a particle’s intrinsic properties to its advantage without altering the original structure or disrupting the viability of the cell which is highly attractive for cancer research.
Mechanical Characterization of the Wall of a Tissue Engineered Pulmonary Valve Conduit: A Twenty Week In Vivo Study
Authors: Eckert Chad E. , Gottlieb Danielle , Padera Robert F. , Schoen Frederick J. , Mayer John E. , Sacks Michael S.
Published: July 2013

Current clinical options for congential pulmonary valve disease are limited and associated with several complications, including lack of somatic growth in replacements. Often, surgical intervention also requires the reconstruction of the right ventricular outflow tract. Tissue engineered pulmonary valved conduits have received much attention as a potential therapy, offering prospective long-term functional improvements and accommodating somatic growth [1]. Though in vitro work has been performed, little is known concerning the physical properties and quality of the tissue produced in vivo, owing to small specimen sample sizes and a lack of detailed mechanical analyses. This work focuses on elucidating in vivo time-course changes in the mechanical quality of tissue engineered pulmonary valve conduit.
On the Mechanics of Partially Mineralized Tissues and Their Implications for the Attachment of Tendon to Bone
Authors: Liu Yanxin , Birman Victor , Chen Chanqing , Thomopoulos Stavros , Genin Guy M.
Published: July 2013

The mechanical implications of adding prescribed amounts of mineral to collagen are important for understanding bone development and the attachment of tendon to bone. Bone and tendon both have at their core hierarchical networks of collagen that has been elucidated recently at the nanoscale [1]. In bone and in partially mineralized tissues, this network accommodates varying degrees of mineral at the nanoscale in channels that that form within collagen fibrils, and subsequently on the exterior of fibrils [2]. We hypothesized that the details of this accommodation of mineral have important mechanical consequences for partially mineralized tissues, and built a simple multi-scale model to quantify these effects.
Transport in Pulsatile Axisymmetric Stented Arterial Models From Location-Dependent Variations in Permeability and Mechanical Properties
Authors: Keyes Joseph T. , Simon Bruce R. , Vande Geest Jonathan P.
Published: July 2013

Drug-eluting stents (DESs) perform their antiproliferative effects through the use of localized drug delivery. The delivery may be computationally modeled to determine efficacy of the DES-tissue system and utilizes coupled convective and diffusive transport. Since the movement of solutes through the wall is via the coupled effects of convective and diffusive transport, the relative influence of these factors provides insight into the governing forces of localized DES drug delivery [1].
Experimental Fluid Dynamic Investigation of a Novel Hyper-Elastic Thin Film for Cerebral Aneurysm Treatment
Authors: Babiker Haithem , Chun Youngjae , Kealey Colin P. , Carman Gregory P. , Levi Dan S. , Frakes David H.
Published: July 2013

Wide-neck and giant cerebral aneurysms are difficult to treat with conventional endovascular or surgical means [1]. Recently, stand-alone stent treatment has been explored as a viable treatment option for these aneurysms. Two goals of standalone stent design are to permit flexible conformation of the stent through tortuous vessels and to provide sufficient coverage across the aneurysmal neck [2]. Stents that achieve those goals can facilitate the long-term physiological processes that exclude the aneurysmal sac from circulation. Thrombosis within the sac is an important intermediate step, which may begin with the elimination of aneurysmal inflow [3].
Mixing Enhancement in Microfluidic Devices Using Contactless Dielectrophoresis (cDEP)
Authors: Salmanzadeh Alireza , Shafiee Hadi , Stremler Mark A. , Davalos Rafael V.
Published: July 2013

Rapid mixing is necessary in lab-on-a-chip (LOC) and Micro Total Analysis Systems (μTAS) devices for chemical and biological processes [1]. Because of the small length scale of microdevices, rapid efficient mixing is difficult to achieve. Thus mixing without any intentional stretching and folding of interfaces is dominated by molecular diffusion, which takes a long time relative to the typical operating timescale of these microdevices. To address this need, various techniques for enhancing mixing in microdevices have been proposed [1]. Electrokinetic mixing has proven to be an efficient method for actively mixing solutions or microparticles [2]. Among electrokinetics techniques, DEP, the motion of a particle in a suspending medium due to the presence of a non-uniform electric field [3], has shown a great potential for particle separation, manipulation, and identification. However, there is not much reported use of DEP for mixing enhancement reported in the literature. Lee et al. [4] presented a micromixer that uses DEP force to generate chaotic trajectories within a mixing chamber. Although DEP has been a very successful technique to manipulate microparticles, it has some drawbacks such as electrolysis (bubble formation), electrode delamination and sample contamination.
Directed Cellular Dynamics on Aligned STEP Fibrous Mechanistic Microenvironments
Authors: Sheets Kevin , Nain Amrinder
Published: July 2013

Cells attach to and interact with their immediate mechanistic native microenvironment. However, the current state-the-art in vitro cell studies are performed on flat substrates of glass, plastic or gel. [1]. The native environment consisting of an assembly of protein nanofibers forming the extracellular matrix (ECM) offers different mechanistic environments for different tissues, which elicits diverse cellular behavior [2]. Recently, there is increased interest in mimicking the ECM by depositing polymeric fibers in single and multiple layers using electrospinning, template synthesis, and micro dry-spinning. The key fibrous spatial parameters (diameter, alignment, spacing, and orientation) can be designed to generate microenvironments of varying mechanical properties. However, the exact role of these parameters on cellular behavior is not clearly understood. Hence, in this study we explore the topological-mechanistic effects of fibrous scaffolds on dynamics of different cell types.
Enrichment of Cancer Cells Using a High Throughput Contactless Dielectrophoretic (CDEP) Microfluidic Device
Authors: Salmanzadeh Alireza , Shafiee Hadi , Sano Mike B. , Stremler Mark A. , Davalos Rafael V.
Published: July 2013

Selective concentration of microparticles is a very important process in many medical and biological applications such as early cancer detection. It has been shown that dielectrophoresis (DEP), the motion of a particle due to its polarization in the presence of a non-uniform electric field, is a method for enrichment of bioparticels based on their electrical properties and size [1, 2, 3]. Bioparticels can be concentrated using DEP by changing applied voltage and frequency, media and particles conductivity and permittivity, and geometry of microchannel and electrodes. DEP has been used to separate circulating tumor cells (CTCs) from clinical blood, breast tumor cells from CD34+ hemopoietic stem cells, breast tumor cells from peripheral blood, leukemia cells from blood.
Effect of Non-Uniform Material De-Cohesion on Crack Initiation From Notches in Crosslinked UHMWPE
Authors: Sirimamilla P. Abhiram , Furmanski Jevan , Rimnac Clare M.
Published: July 2013

Ultra High Molecular Weight Polyethylene (UHMWPE) has been successfully used as a bearing material in total joint arthroplasty for the last 4 decades [1] but about 5%–10% of the implants undergo revision surgery in the first 10 years of implantation [2]. Crack initiation from a stress-concentration design feature (e.g., a sharp corner of a locking mechanism on an acetabular component) has been observed to lead to catastrophic failure in-vivo [3]. Therefore, it is important to understand crack initiation from clinically relevant notches to mitigate the risk of component fracture. UHMWPE is a semi-crystalline polymer and little is known about the physical mechanisms governing crack tip phenomena. The time dependent theoretical expression of fracture mechanics indicates that the critical fracture energy (Jc) varies with crack initiation time (ti) with an exponent ‘n’ (Equation 1).
Local and Distant Intramedullary Pressure and Bone Strain by Dynamic Hydraulic Stimulation
Authors: Qin Y. X. , Hu M. , Serra-Hsu F. , Cheng J. , Ferreri S. , Huang Y. , Zhang Z. K. , Lin L. , Evangelista D.
Published: July 2013

Osteoporosis gives rise to fragile bones that have higher fracture risks due to diminished bone mass and altered bone microarchitecture [1]. Mechanical loading mediated bone adaptation has demonstrated promising potentials as a non-pharmacological alteration for both osteogenic response and attenuation of osteopenia [2]. Intramedullary pressure (ImP) has been proposed as a key factor for fluid flow initiation and mechanotransductive signal inductions in bone. It is also suggested that integration of strain signals over time allows low-level mechanical strain in the skeleton to trigger osteogenic activities. The potential bone fluid flow induced by strain and ImP mediates adaptive responses in the skeleton [3]. Previous in vivo studies using oscillatory electrical stimulations showed that dynamic muscle contractions can generate ImP and bone strain to mitigate disuse osteopenia in a frequency-dependent manner. To apply ImP alteration as a means for bone fluid flow regulation, it may be necessary to develop a new method that could couple external loading with internal bone fluid flow. In order to further study the direct effect of ImP on bone adaptation, it was hypothesized that external dynamic hydraulic stimulation (DHS) can generate ImP with minimal strain in a frequency-dependent manner. The aim of this study was to evaluate the immediate effects on local and distant ImP and bone strain induced by a novel, non-invasive dynamic external pressure stimulus in response to a range of loading frequencies.
A Two/Three Dimension Model of Intracellular Ice Formation in Cryo-Preservation
Authors: Li Wei , Zhang Aili , Xu Lisa X.
Published: July 2013

Cryo-preservation of precious cells like stem cells and oocytes requires high success rate because they are hard to obtain and limited in number. Simulation of the freezing process could: (1)Serve as an inexpensive replacement for vivo experiments (when collecting complete experiment data is too costly or time consuming); (2) Help optimize the cyro-preservation protocols. (3) Help to confirm or disprove intracellular ice formation theories. Most of the published models simulating the water loss and intracellular ice formation have treated the cell as a uniform volume with evenly distributed water content. Albeit being a well-founded premise given consideration to the minuteness size of the cell, there are several issues it cannot properly address.
Improvements in an Automatic Mesh Generation System for Complex Biological Topologies: Multi-Domain Analysis
Authors: Doehring Todd C.
Published: July 2013

Fully automated mesh generation remains a difficult challenge for complex organic shapes encountered in bioengineering. The topologies are often complex and in most practical applications have multiple domains.
Dynamics of Membrane Rafts, Talin, and Actin at Nascent and Mechanically Perturbed Focal Adhesions
Authors: Fuentes Daniela E. , Butler Peter J.
Published: July 2013

A single endothelial cell was deformed at the apical surface by binding a functionalized nanoelectrode probe to a predetermined location on the surface of the cell. After identifying the point of contact, as recognized by the electronic signature of the nanoelectrode, and allowing binding to the cell of the fibronectin-functionalized tip, a focal adhesion site was induced at the probe site. The probe was displaced thereby applying a prescribed shear deformation to the surface of the cell. Locations of membrane rafts were identified by cholera toxin, and focal adhesion proteins were assessed using RFP-talin, and GFP-actin. Mechanical coupling and kinetics of assembly of these labeled proteins were measured using time-lapse fluorescent images taken under 60X with a multi-point confocal scanner. Raft marker GM1, Actin, and Talin were observed to sequentially accumulate at probe site with different kinetics not only upon probe contact but also upon deformation. Following deformation, later transient motion of rafts in the opposite direction of initial deformation was observed suggesting that rafts recoil. In conclusion, we report a novel nanoelectrode-based method for controlled manipulation of the cell surface and observed mechanical coupling of focal adhesions and cross-linked lipid rafts.
Innovative Scaffold Design for Soft Tissue-to-Bone Interface Tissue Engineering
Authors: Subramony Siddarth D. , Spalazzi Jeffrey P. , Moffat Kristen L. , Rodeo Scott A. , Lu Helen H.
Published: July 2013

Soft tissue-based ACL reconstruction grafts are limited by their inability to reestablish a functional interface with bone tissue[1–2]. The native ACL-bone interface consists of three regions: ligament, fibrocartilage, and bone[3–5]. Graft integration is a critical factor governing its clinical success, and the regeneration of an anatomic interface on synthetic or biological ACL grafts will improve clinical outcome. Our interface tissue engineering effort has focused on biomimetic scaffold design to recapitulate the inherent complexity of the ligament-to-bone interface and ultimately, to guide interface regeneration. To this end, we have designed a tri-phasic scaffold comprised of three distinct yet continuous phases, each designed for the formation of a specific tissue type found at the ACL-to-bone interface, as well as a bi-phasic collar to promote the formation of fibrocartilage on ACL reconstruction grafts and also enhance osteointegration.
A Tribute to Professor Savio L.Y. Woo: A Superb Scholar and Great Leader in Bioengineering
Authors: Chien Shu
Published: July 2013

It is a great pleasure and privilege for me to participate in the symposium in honor of Dr. Savio Woo’s 70th birthday. Professor Woo has had a truly outstanding career in bioengineering as a scholar and leader that has spanned four decades. He has superb intellectual capability and made full use of it by working with strong dedication, continuous innovation, and outstanding leadership, culminating in his truly remarkable career as a superb scholar and great leader in Bioengineering.
Hysteresis in experimental I–V curves of electron hop funnels
Authors: Rowe Tyler , Pearlman Marcus , Browning Jim
Published: July 2013

Electron hop funnels provide a method to integrate field emission arrays into microwave vacuum electron devices, to protect the arrays, and to provide a method to study the secondary electron characteristics of dielectrics. A hop funnel is a dielectric material with an electrode, known as the hop electrode, placed around the narrow end (exit) of the funnel to control the current transmitted through the device. Current is transmitted through the funnel via electron-hopping transport. This work investigates a hysteresis observed in the current–voltage characteristic of the device. The experimental results showing the observed hysteresis will be presented. This work will demonstrate that charging on the bottom of the hop funnel is not the fundamental cause of the hysteresis.
Overcoming Preexisting Humoral Immunity to AAV Using Capsid Decoys
Authors: Mingozzi Federico , Anguela Xavier M. , Pavani Giulia , Chen Yifeng , Davidson Robert J. , Hui Daniel J. , Yazicioglu Mustafa , Elkouby Liron , Hinderer Christian J. , Faella Armida , Howard Carolann , Tai Alex , Podsakoff Gregory M. , Zhou Shangzhen , Basner-Tschakarjan Etiena , Wright John Fraser , High Katherine A.
Published: July 2013

Capsid decoys enhance the efficacy of AAV vector transduction after systemic delivery in the presence of neutralizing antibodies.
Genomics in Clinical Practice: Lessons from the Front Lines
Authors: Jacob Howard J. , Abrams Kelly , Bick David P. , Brodie Kent , Dimmock David P. , Farrell Michael , Geurts Jennifer , Harris Jeremy , Helbling Daniel , Joers Barbara J. , Kliegman Robert , Kowalski George , Lazar Jozef , Margolis David A. , North Paula , Northup Jill , Roquemore-Goins Altheia , Scharer Gunter , Shimoyama Mary , Strong Kimberly , Taylor Bradley , Tsaih Shirng-Wern , Tschannen Michael R. , Veith Regan L. , Wendt-Andrae Jaime , Wilk Brandon , Worthey Elizabeth A.
Published: July 2013

This Commentary explores the challenges in launching a medical genomics clinic for whole genome sequencing and analysis of patient samples.
Involvement of FtsE ATPase and FtsX Extracellular Loops 1 and 2 in FtsEX-PcsB Complex Function in Cell Division of Streptococcus pneumoniae D39
Authors: Sham Lok-To , Jensen Katelyn R. , Bruce Kevin E. , Winkler Malcolm E.
Published: July 2013

The FtsEX protein complex has recently been proposed to play a major role in coordinating peptidoglycan (PG) remodeling by hydrolases with the division of bacterial cells. According to this model, cytoplasmic FtsE ATPase interacts with the FtsZ divisome and FtsX integral membrane protein and powers allosteric activation of an extracellular hydrolase interacting with FtsX. In the major human respiratory pathogen
Streptococcus pneumoniae
(pneumococcus), a large extracellular-loop domain of FtsX (ECL1
FtsX
) is thought to interact with the coiled-coil domain of the PcsB protein, which likely functions as a PG amidase or endopeptidase required for normal cell division. This paper provides evidence for two key tenets of this model. First, we show that FtsE protein is essential, that depletion of FtsE phenocopies cell defects caused by depletion of FtsX or PcsB, and that changes of conserved amino acids in the FtsE ATPase active site are not tolerated. Second, we show that temperature-sensitive (Ts)
pcsB
mutations resulting in amino acid changes in the PcsB coiled-coil domain (CC
PcsB
) are suppressed by
ftsX
mutations resulting in amino acid changes in the distal part of ECL1
FtsX
or in a second, small extracellular-loop domain (ECL2
FtsX
). Some FtsX suppressors are allele specific for changes in CC
PcsB
, and no FtsX suppressors were found for amino acid changes in the catalytic PcsB CHAP domain (CHAP
PcsB
). These results strongly support roles for both ECL1
FtsX
and ECL2
FtsX
in signal transduction to the coiled-coil domain of PcsB. Finally, we found that
pcsB
CC
(Ts) mutants (Ts mutants carrying mutations in the region of
pcsB
corresponding to the coiled-coil domain) unexpectedly exhibit delayed stationary-phase autolysis at a permissive growth temperature.

IMPORTANCE
Little is known about how FtsX interacts with cognate PG hydrolases in any bacterium, besides that ECL1
FtsX
domains somehow interact with coiled-coil domains. This work used powerful genetic approaches to implicate a specific region of pneumococcal ECL1
FtsX
and the small ECL2
FtsX
in the interaction with CC
PcsB
. These findings identify amino acids important for
in vivo
signal transduction between FtsX and PcsB for the first time. This paper also supports the central hypothesis that signal transduction between pneumococcal FtsX and PcsB is linked to ATP hydrolysis by essential FtsE, which couples PG hydrolysis to cell division. The classical genetic approaches used here can be applied to dissect interactions of other integral membrane proteins involved in PG biosynthesis. Finally, delayed autolysis of the
pcsB
CC
(Ts) mutants suggests that the FtsEX-PcsB PG hydrolase may generate a signal in the PG necessary for activation of the major LytA autolysin as pneumococcal cells enter stationary phase.
LOW VOLTAGE, LOW POWER CHEBYSHEV FILTER IN 0.18 μm CMOS TECHNOLOGY
Authors: REKHA S. , LAXMINIDHI T.
Published: July 2013

This paper presents an active-RC continuous time filter in 0.18 μm standard CMOS technology intended to operate on a very low supply voltage of 0.5 V. The filter designed, has a 5th order Chebyshev low pass response with a bandwidth of 477 kHz and 1-dB passband ripple. A low-power operational transconductance amplifier (OTA) is designed which makes the filter realizable. The OTA uses bulk-driven input transistors and feed-forward compensation in order to increase the Dynamic Range and Unity Gain Bandwidth, respectively. The paper also presents an equivalent circuit of the OTA and explains how the filter can be modeled using descriptor state-space equations which will be used for design centering the filter in the presence of parasitics. The designed filter offers a dynamic range of 51.3 dB while consuming a power of 237 μW.
WEAKLY-INTERACTING MASSIVE PARTICLES IN TORSIONALLY-GRAVITATING DIRAC THEORY
Authors: FABBRI LUCA
Published: July 2013

We shall consider the problem of Dark Matter (DM) in torsion gravity with Dirac matter fields; we will consider the fact that if Weakly-Interacting Massive Particles in a bath are allowed to form condensates then torsional effects may be relevant even at galactic scales: we show that torsionally-gravitating Dirac fields have interesting properties for the problem of DM. We discuss consequences.
REGIOSELECTIVITY INVESTIGATION FOR THE PYROLYSIS OF XANTHATES: A COMPUTATIONAL STUDY
Authors: WU PING , TRUONG JOHNNY , HUANG YONGSHUN , LI JIAXING
Published: July 2013

MP2/6-31+G(d,p)//MP2/6-31G(d) method was employed to investigate the pyrolyses of O -sec-butyl S -methyl xanthate (Chugeav reaction) and S -sec-butyl O -methyl xanthate, which gave regioselective products of E-butene, Z-butene and 1-butene. Both procedures were found to have 13 possible pathways, of which nine pathways would generate the alkene products. For O -sec-butyl S -methyl xanthate, the computational results indicated that the most favorable three pathways corresponded to a two-step mechanism, with the rate-determining step to be a thion sulfur atom involved six-membered ring transition states. The calculated products distribution was consistent with the experimental observations. However, for S -sec-butyl O -methyl xanthate, thiol-participated four-membered ring transition states were found to be more energetically favored than the six-membered ring transition state to produce 1-butene, which can be attributed to a larger sulfur atomic size than an oxygen atom. As the calculation result, only trace amount of 1-butene could be obtained with a major product being E-butene and Z-butene as a minority.
REVIEW OF METAL, CARBON AND POLYMER NANOPARTICLES FOR INFRARED PHOTOTHERMAL THERAPY
Authors: GRAHAM ELIZABETH G. , MACNEILL CHRISTOPHER M. , LEVI-POLYACHENKO NICOLE H.
Published: July 2013

The aim of this review is to provide an up-to-date overview of nanoparticles developed for use as photothermal therapy agents (PTT) over the past five years. The main emphasis is on nanoparticles that absorb near infrared (NIR) light for PTT of cancer. Mild hyperthermia, including drug delivery, versus thermal ablation is also discussed. Recent advances in the synthesis of highly anisotropic novel metal nanoparticles for PTT are described. New metals and metal oxide complexes, as well as the use of quantum dots for PTT and as imaging agents are newer areas of development that are explained. This review also highlights current progress in the development of carbon nanoparticles, including reduced graphene oxide for both thermal ablation as well as drug delivery. The review culminates in the recent use electrically conductive polymer nanoparticles for hyperthermia. The advantages and unique features of these contemporary nanoparticles being used for PTT are highlighted. The goal of the present work is to describe the recent evolution of nanoparticles for NIR stimulated PTT, and highlight the innovations and future directions.
Neogene rock uplift and erosion in northern Borneo: evidence from the Kinabalu granite, Mount Kinabalu
Authors: Cottam M. A. , Hall R. , Sperber C. , Kohn B. P. , Forster M. A. , Batt G. E.
Published: July 2013

Thermochronological data from the Kinabalu granite, emplaced between
c
. 7.2 and 7.8 Ma, provide a unique record of northern Borneo’s exhumation during the Neogene. Biotite
40
Ar/
39
Ar ages (
c
. 7.32–7.63 Ma) record rapid cooling of the granite in the Late Miocene as it equilibrated with ambient crustal temperatures. Zircon fission-track ages (
c
. 6.6–5.8 Ma) and apatite (U–Th–Sm)/He ages (central age
c
. 5.5 Ma) indicate rapid cooling during the Late Miocene–Early Pliocene. This cooling reflects exhumation of the granite, uplift and erosion bringing it closer to the Earth’s surface. Thermochronological age versus elevation relationships suggest exhumation rates of more than 7 mm a
−1
during the latest Miocene and Early Pliocene. Neither the emplacement of the Kinabalu granite nor its exhumation is related to the Sabah orogeny, which terminated in the Early Miocene. Instead, granite magmatism was caused by extension related to subduction rollback of the Sulu Arc, and Mio-Pliocene exhumation of the Kinabalu granite was driven either by lithospheric delamination or break-off of a subducted slab beneath Sabah. Plio-Pleistocene tectonism offshore and onshore northern Borneo reflects continuing large-scale gravity-driven tectonics in the region.

Supplementary material:

Full
40
Ar/
39
Ar, fission-track and (U–Th–Sm)/He analytical data and
40
Ar/
39
Ar age spectra plots can be found at
www.geolsoc.org.uk/SUP18613
.
Taste dysfunction in BTBR mice due to a mutation ofItpr3, the inositol triphosphate receptor 3 gene
Authors: Tordoff Michael G. , Ellis Hillary T.
Published: July 2013

The BTBR T+tf/J (BTBR) mouse strain is indifferent to exemplars of sweet, Polycose, umami, bitter, and calcium tastes, which share in common transduction by G protein-coupled receptors (GPCRs). To investigate the genetic basis for this taste dysfunction, we screened 610 BTBR × NZW/LacJ F2hybrids, identified a potent QTL on chromosome 17, and isolated this in a congenic strain. Mice carrying the BTBR/BTBR haplotype in the 0.8-Mb (21-gene) congenic region were indifferent to sweet, Polycose, umami, bitter, and calcium tastes. To assess the contribution of a likely causative culprit, Itpr3, the inositol triphosphate receptor 3 gene, we produced and tested Itpr3 knockout mice. These were also indifferent to GPCR-mediated taste compounds. Sequencing the BTBR form of Itpr3 revealed a unique 12 bp deletion in Exon 23 (Chr 17: 27238069; Build 37). We conclude that a spontaneous mutation of Itpr3 in a progenitor of the BTBR strain produced a heretofore unrecognized dysfunction of GPCR-mediated taste transduction.
Research of High-Speed FBG Demodulation System for Distributed Dynamic Monitoring of Mechanical Equipment
Authors: Li Zhengying , Xu Zhiqiang , Tang Zhihao , Zhao Meng , Cai Linjun , Liu Quan
Published: July 2013

This paper designs and implements the high-speed FBG demodulation system which can demodulate multiple FBG sensors (up to 64 sensors in series per channel) of 4 channels synchronously. The system is based on the method of tunable F-P filter. Both the nonlinear effect and the temperature drift effect of the F-P filter are eliminated by applying the triangular-like drive signal and reference channels. In addition, a high-speed adaptive algorithm for peak-find is designed for the system. The experiment results show that, for the whole system, the stability is 2 pm, the resolution is 1 pm, the linearity is 0.999, the measurement precision is 20 pm, and the demodulation frequency is 4 kHz. Consequently, the system is very suitable for distributed dynamic monitoring of complicated mechanical equipment.
Lipoxin A4Preconditioning and Postconditioning Protect Myocardial Ischemia/Reperfusion Injury in Rats
Authors: Zhao Qifeng , Shao Lan , Hu Xingti , Wu Guowei , Du Jie , Xia Jie , Qiu Huixian
Published: July 2013

This study aims to investigate the pre- and postconditioning effects of lipoxin A4(LXA4) on myocardial damage caused by ischemia/reperfusion (I/R) injury. Seventy-two rats were divided into 6 groups: sham groups (C1and C2), I/R groups (I/R1and I/R2), and I/R plus LXA4preconditioning and postconditioning groups (LX1and LX2). The serum levels of IL-1β, IL-6, IL-8, IL-10, TNF-α, and cardiac troponin I (cTnI) were measured. The content and the activity of Na+-K+-ATPase as well as the superoxide dismutase (SOD), and malondialdehyde (MDA) levels were determined. Along with the examination of myocardium ultrastructure and ventricular arrhythmia scores (VAS), connexin 43 (Cx43) expression were also detected. Lower levels of IL-1β, IL-6, IL-8, TNF-α, cTnI, MDA content, and VAS and higher levels of IL-10, SOD activity, Na+-K+-ATPase content and activity, and Cx43 expression appeared in LX groups than I/R groups. Besides, H&E staining, TEM examination as well as analysis of gene, and protein confirmed that LXA4preconditioning was more effective than postconditioning in preventing arrhythmogenesis via the upregulation of Cx43. That is, LXA4postconditioning had better protective effect on Na+-K+-ATPase and myocardial ultrastructure.
The Role of Neurotransmitters in Protection against Amyloid-β Toxicity by KiSS-1 Overexpression in SH-SY5Y Neurons
Authors: Chilumuri Amrutha , Milton Nathaniel G. N.
Published: July 2013

Recent studies have suggested that the kisspeptin (KP) and kissorphin (KSO) peptides have neuroprotective actions against the Alzheimer’s amyloid-β (Aβ) peptide. Overexpression of the human KiSS-1 gene that codes for KP and KSO peptides in SH-SY5Y neurons has also been shown to inhibit Aβ neurotoxicity. The in vivo actions of KP include activation of neuroendocrine and neurotransmitter systems. The present study used antagonists of KP, neuropeptide FF (NPFF), opioids, oxytocin, estrogen, adrenergic, cholinergic, dopaminergic, serotonergic, and γ-aminobutyric acid (GABA) receptors plus inhibitors of catalase, cyclooxygenase, nitric oxide synthase, and the mitogen activated protein kinase cascade to characterize the KiSS-1 gene overexpression neuroprotection against Aβ cell model. The results showed that KiSS-1 overexpression is neuroprotective against Aβ and the action appears to involve the KP or KSO peptide products of KiSS-1 processing. The mechanism of neuroprotection does not involve the activation of the KP or NPFF receptors. Opioids play a role in the toxicity of Aβ in the KiSS-1 overexpression system and opioid antagonists naloxone or naltrexone inhibited Aβ toxicity. The mechanism of KiSS-1 overexpression induced protection against Aβ appears to have an oxytocin plus a cyclooxygenase dependent component, with the oxytocin antagonist atosiban and the cyclooxygenase inhibitor SC-560 both enhancing the toxicity of Aβ.
Maternal Cardiac Arrest: A Practical and Comprehensive Review
Authors: Jeejeebhoy Farida M. , Morrison Laurie J.
Published: July 2013

Cardiac arrest during pregnancy is a dedicated chapter in the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care; however, a robust maternal cardiac arrest knowledge translation strategy and emergency response plan is not usually the focus of institutional emergency preparedness programs. Although maternal cardiac arrest is rare, the emergency department is a high-risk area for receiving pregnant women in either prearrest or full cardiac arrest. It is imperative that institutions review and update emergency response plans for a maternal arrest. This review highlights the most recent science, guidelines, and recommended implementation strategies related to a maternal arrest. The aim of this paper is to increase the understanding of the important physiological differences of, and management strategies for, a maternal cardiac arrest, as well as provide institutions with the most up-to-date literature on which they can build emergency preparedness programs for a maternal arrest.
Alkali/Surfactant/Polymer Flooding in the Daqing Oilfield Class II Reservoirs Using Associating Polymer
Authors: Feng Ru-Sen , Guo Yong-Jun , Zhang Xin-Min , Hu Jun , Li Hua-Bing
Published: July 2013

Hydrophobically modified associating polyacrylamide (HAPAM) has good compatibility with the Daqing heavy alkylbenzene sulfonate surfactant. The HAPAM alkali/surfactant/polymer (ASP) system can generate ultralow interfacial tension in a wide range of alkali/surfactant concentrations and maintain stable viscosity and interfacial tension for 120 days. The HAPAM ASP system has good injectivity for the Daqing class II reservoirs (100–300 × 10−3 μm2) and can improve oil recovery by more than 25% on top of water flooding. In the presence of both the alkali and the surfactant, the surfactant interacts with the associating groups of the polymer to form more micelles, which can significantly enhance the viscosity of the ASP system. Compared with using HPAM (Mw  =  2.5 MDa), using HAPAM can reduce the polymer use by more than 40%.
Optimal Homotopy Asymptotic Method for Solving the Linear Fredholm Integral Equations of the First Kind
Authors: Almousa Mohammad , Ismail Ahmad
Published: July 2013

The aim of this study is to present the use of a semi analytical method called the optimal homotopy asymptotic method (OHAM) for solving the linear Fredholm integral equations of the first kind. Three examples are discussed to show the ability of the method to solve the linear Fredholm integral equations of the first kind. The results indicated that the method is very effective and simple.
Some Integrals Involvingq-Laguerre Polynomials and Applications
Authors: Cao Jian
Published: July 2013

The integrals involving multivariateq-Laguerre polynomials and then auxiliary ones are studied. In addition, the representations ofq-Hermite polynomials byq-Laguerre polynomials and their related integrals are given. At last, some generalized integrals associated with generalizedq-Hermite polynomials are deduced.
Personalization in Mobile Activity Recognition System Using K-Medoids Clustering Algorithm
Authors: Vo Quang Viet , Hoang Minh Thang , Choi Deokjai
Published: July 2013

Nowadays mobile activity recognition (AR) has been creating great potentials in many applications including mobile healthcare and context-aware systems. Human activities could be detected based on sensory data that are available on today's smart phone. In this study, we consider mobile phones as an independent device since sending the data to central server can generate privacy issues. Furthermore, applying AR on mobile phone does not only require an effective accuracy rate but also the lowest power consumption. Normally, an AR model learnt from acceleration data of a specific person is distributed to other people to recognize the same activities instead of generating different models individually. This work often cannot create accurate results on the prediction in broad range of participants. Moreover, such AR model also has to allow each user to update his new activities independently. Therefore, we propose an algorithm that integrates Support Vector Machine classifier and K-medoids clustering method to resolve completely the demand.