bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient computation of the Kauffman bracket
Authors: Ellenberg Lauren , Newman Gabriella , Sawin Stephen , Shi Jonathan
Published: June 2014

This paper bounds the computational cost of computing the Kauffman bracket of a link in terms of the crossing number of that link. Specifically, it is shown that the image of a tangle with g boundary points and n crossings in the Kauffman bracket skein module is a linear combination of O(2g) basis elements, with each coefficient a polynomial with at most n non-zero terms, each with integer coefficients, and that the link can be built one crossing at a time as a sequence of tangles with maximum number of boundary points bounded by [Formula: see text] for some C. From this it follows that the computation of the Kauffman bracket of the link takes time and memory a polynomial in n times [Formula: see text].
ON OPTIMAL CHEMOTHERAPY FOR HETEROGENEOUS TUMORS
Authors: LEDZEWICZ URSZULA , SCHÄTTLER HEINZ
Published: June 2014

A mathematical model for cancer chemotherapy of heterogeneous tumor populations is considered as an optimal control problem with the objective to minimize the tumor burden over a prescribed therapy horizon. While an upfront maximum tolerated dose (MTD) regimen with rest-period has been confirmed as mathematically optimal for models when the tumor population is homogeneous, in the presence of partially sensitive or even resistant cells, protocols that administer the therapeutic agents at lower dose rates described by so-called singular controls become a viable alternative. In this paper, the structure of protocols that follow an initial upfront maximum dose treatment with reduced dose rate singular controls is investigated. Such protocols reflect structures which in the medical literature sometimes are called chemo-switch protocols.
MODELING AND OPTIMAL CONTROL FOR ANTIRETROVIRAL THERAPY
Authors: GRIGORIEVA ELLINA V. , KHAILOV EVGENII N. , BONDARENKO NATALIA V. , KOROBEINIKOV ANDREI
Published: June 2014

We consider a three-dimensional nonlinear control model based on the Wodarz HIV model. The model phase variables are populations of the uninfected and infected target cells and the concentration of an antiretroviral drug. The drug intake rate is assumed to be a bounded control function. An optimal control problem of minimizing the cumulative infection level (the infected cells population) on a given time interval is stated and solved, and the types of the optimal control for different model parameters are found by analytical methods. We thereby reduce the two-point boundary value problem (TPBVP) for the Pontryagin maximum principle to a problem of the finite-dimensional optimization. Numerical results are presented to illustrate the optimal solution.
A NEW MODEL FOR THE SUCTION PRESSURE UNDER A CONTACT LENS
Authors: MAKI KARA L. , ROSS DAVID S.
Published: June 2014

We present a new approach to compute the suction pressure under a soft contact lens. When a soft contact lens is placed on an eye, it is subjected to forces from the tear film in which it is immersed and from the blinking eyelid. In response, the lens bends and stretches. The equilibration of these forces generates a suction pressure that keeps the lens on the cornea. In this paper, we develop a mathematical model of the elastic equilibrium of a soft contact lens that allows us to predict the suction pressure distribution under such a lens. We explore the influence of the shape of the lens and its elastic properties on the suction pressure.
MODELING THE IMPACT OF AWARENESS CREATED BY MEDIA CAMPAIGNS ON VACCINATION COVERAGE IN A VARIABLE POPULATION
Authors: SHARMA ANUPAMA , MISRA A. K.
Published: June 2014

Vaccines are a core component of any preventive strategy designed to ensure the global public health. A major factor influencing the successful implementation of any immunization program is awareness and public acceptance of the vaccine. The present study focuses on potential impacts of awareness created by media campaigns on vaccination coverage of hepatitis B. In this paper, a SIR model with vital dynamics in a population of varying size is investigated, which couples hepatitis B vaccination and awareness created by media within a single framework. It is assumed that media campaigns propagate awareness about measures requisite for escaping the chances of contracting hepatitis B. The awareness created by media motivates people to get vaccinated and attain full immunization against hepatitis B virus. For analyzing the model, stability theory of differential equations is employed. First, equilibria of the system comprising fractions of the population are obtained and their stability behavior is discussed. Then the asymptotic behavior of total population is discussed in detail. Three threshold parameters R0, R1and R2governing the dynamics of infection and total population are also affirmed. The findings of numerical simulations are also in line with analytically obtained results.
An Overview of Knowledge Management Techniques for e-Recruitment
Authors: Martinez-Gil Jorge
Published: June 2014

The number of potential job candidates and therefore, costs associated with their hiring, has grown significantly in the recent years. This is mainly due to both the complicated situation of the labour market and the increased geographical flexibility of employees. Some initiatives for making the e-Recruitment processes more efficient have notably improved the situation by developing automatic solutions. But there are still some challenges that remain open since traditional solutions do not consider semantic relations properly. This problem can be appropriately addressed by means of a sub discipline of knowledge management called semantic processing. Therefore, we overview the major techniques from this field that can play a key role in the design of a novel business model that is more attractive for job applicants and job providers.
Environment-induced mixing processes in quantum walks
Authors: Lehman Lauri
Published: June 2014

The mixing process of discrete-time quantum walks on one-dimensional lattices is revisited in a setting where the walker is coupled to an environment, and the time evolution of the walker and the environment is unitary. The mixing process is found to be incomplete, in the sense that the walker does not approach the maximally mixed state indefinitely, but the distance to the maximally mixed state saturates to some finite value depending on the size of the environment. The quantum speedup of mixing time is investigated numerically as the size of the environment decreases from infinity to a finite value. The mixing process in this unitary setting can be explained by interpreting it as an equilibration process in a closed quantum system, where subsystems can exhibit equilibration even when the entropy of the total system remains zero.
Using long-range contact number information for protein secondary structure prediction
Authors: Feng Yonge , Luo Liaofu
Published: June 2014

In this paper, we first combine tetra-peptide structural words with contact number for protein secondary structure prediction. We used the method of increment of diversity combined with quadratic discriminant analysis to predict the structure of central residue for a sequence fragment. The method is used tetra-peptide structural words and long-range contact number as information resources. The accuracy of Q3 is over 83% in 194 proteins. The accuracies of predicted secondary structures for 20 amino acid residues are ranged from 81% to 88%. Moreover, we have introduced the residue long-range contact, which directly indicates the separation of contacting residue in terms of the position in the sequence, and examined the negative influence of long-range residue interactions on predicting secondary structure in a protein. The method is also compared with existing prediction methods. The results show that our method is more effective in protein secondary structures prediction.
Flow latency analysis of component-based embedded software: Model and methodology
Authors: Tang Lei , Wang Hanbo
Published: June 2014

A wide variety of ways to analyze the end-to-end latency emerges due to the feature of component-based software. The researchers began to see that the latency is more sensitive to the data and control flows than the software architecture. However, for an embedded software, the latency depends upon the hardware heavily. To illuminate the feature clearly, we extend the atomic model of component-based software first. A way to specify the flows involved is further developed to identify the end-to-end latency. What is more, a novel methodology that bridges the gap between a constraint on latency and an execution platform is proposed for the embedded software. By constructing a hierarchical architecture, it is available to consider the methodology as a decision problem where the satisfiability module theory (SMT) can be applied. Experimental results demonstrate how the latency analysis conducts with the proposed model and methodology for the complex software architecture.
Stable dielectric response in lead-free relaxor K0.5Na0.5NbO3–SrTiO3 thin films
Authors: Eršte A. , Kupec A. , Kmet B. , Malič B. , Bobnar V.
Published: June 2014

K 0.5 Na 0.5 NbO 3– SrTiO 3 (KNN–STO) thin films of different compositions were prepared by the chemical solution deposition method. While structural investigations confirmed the formation of perovskite solid solution in all developed films, dielectric experiments revealed a relaxor broad dispersive maximum in the sample with 15 mol% of STO, exhibiting for a thin film high ε′ ~ 330 at ~ 210 K. The history-dependent effects of this relaxor sample were compared to those of KNN–STO ceramics and, furthermore, shown to be much weaker than in widely used lead-based ferroelectric and relaxor ( Pb , La )( Zr , Ti ) O 3 ceramics: While fatigue endurance results revealed a slight drop in polarization after 3 × 105 switching cycles, the results of aging of the dielectric constant revealed no notable decrease in its values after 106 s.
Lateral ramps and strike-slip kinematics on Mercury
Authors: Massironi M. , Di Achille G. , Rothery D. A. , Galluzzi V. , Giacomini L. , Ferrari S. , Zusi M. , Cremonese G. , Palumbo P.
Published: June 2014

At a global scale, Mercury is dominated by contractional features manifested as lobate scarps, wrinkle ridges and high-relief ridges. Here, we show that some of these features are associated with strike-slip kinematic indicators, which we identified using flyby and orbital Mercury Dual Imaging System (MDIS) data and digital terrain models. We recognize oblique-shear kinematics along lobate scarps and high-relief ridges by means of (1) map geometries of fault patterns (frontal thrusts bordered by lateral ramps, strike-slip duplexes, restraining bends); (2) structural morphologies indicating lateral shearing (en echelon folding, pop-ups, pull-aparts); and (3) estimates of offsets based on displaced crater rims and differences in elevation between pop-up structures and pull-apart basins and their surroundings. Transpressional faults, documented across a wide range of latitudes, are found associated with reactivated rims of ancient buried basins and, in most cases, linked to frontal thrusts as lateral ramps hundreds of kilometres long. This latter observation suggests stable directions of tectonic transport over wide regions of Mercury's surface. In contrast, global cooling would imply an overall isotropic contraction with limited processes of lateral shearing induced by pre-existent lithospheric heterogeneities. Mantle convection therefore may have played an important role during the tectonic evolution of Mercury.
Mechanosensing at the Vascular Interface
Authors: Tarbell John M. , Simon Scott I. , Curry Fitz-Roy E.
Published: June 2014

Mammals are endowed with a complex set of mechanisms that sense mechanical forces imparted by blood flow to endothelial cells (ECs), smooth muscle cells, and circulating blood cells to elicit biochemical responses through a process referred to as mechanotransduction. These biochemical responses are critical for a host of other responses, including regulation of blood pressure, control of vascular permeability for maintaining adequate perfusion of tissues, and control of leukocyte recruitment during immunosurveillance and inflammation. This review focuses on the role of the endothelial surface proteoglycan/glycoprotein layer—the glycocalyx (GCX)—that lines all blood vessel walls and is an agent in mechanotransduction and the modulation of blood cell interactions with the EC surface. We first discuss the biochemical composition and ultrastructure of the GCX, highlighting recent developments that reveal gaps in our understanding of the relationship between composition and spatial organization. We then consider the roles of the GCX in mechanotransduction and in vascular permeability control and review the prominent interaction of plasma-borne sphingosine-1 phosphate (S1P), which has been shown to regulate both the composition of the GCX and the endothelial junctions. Finally, we consider the association of GCX degradation with inflammation and vascular disease and end with a final section on future research directions.
Induced Pluripotent Stem Cells for Regenerative Medicine
Authors: Hirschi Karen K. , Li Song , Roy Krishnendu
Published: June 2014

With the discovery of induced pluripotent stem (iPS) cells, it is now possible to convert differentiated somatic cells into multipotent stem cells that have the capacity to generate all cell types of adult tissues. Thus, there is a wide variety of applications for this technology, including regenerative medicine, in vitro disease modeling, and drug screening/discovery. Although biological and biochemical techniques have been well established for cell reprogramming, bioengineering technologies offer novel tools for the reprogramming, expansion, isolation, and differentiation of iPS cells. In this article, we review these bioengineering approaches for the derivation and manipulation of iPS cells and focus on their relevance to regenerative medicine.
3D Biofabrication Strategies for Tissue Engineering and Regenerative Medicine
Authors: Bajaj Piyush , Schweller Ryan M. , Khademhosseini Ali , West Jennifer L. , Bashir Rashid
Published: June 2014

Over the past several decades, there has been an ever-increasing demand for organ transplants. However, there is a severe shortage of donor organs, and as a result of the increasing demand, the gap between supply and demand continues to widen. A potential solution to this problem is to grow or fabricate organs using biomaterial scaffolds and a person's own cells. Although the realization of this solution has been limited, the development of new biofabrication approaches has made it more realistic. This review provides an overview of natural and synthetic biomaterials that have been used for organ/tissue development. It then discusses past and current biofabrication techniques, with a brief explanation of the state of the art. Finally, the review highlights the need for combining vascularization strategies with current biofabrication techniques. Given the multitude of applications of biofabrication technologies, from organ/tissue development to drug discovery/screening to development of complex in vitro models of human diseases, these manufacturing technologies can have a significant impact on the future of medicine and health care.
Hydrogeomorphic Effects of Explosive Volcanic Eruptions on Drainage Basins
Authors: Pierson Thomas C. , Major Jon J.
Published: June 2014

Explosive eruptions can severely disturb landscapes downwind or downstream of volcanoes by damaging vegetation and depositing large volumes of erodible fragmental material. As a result, fluxes of water and sediment in affected drainage basins can increase dramatically. System-disturbing processes associated with explosive eruptions include tephra fall, pyroclastic density currents, debris avalanches, and lahars—processes that have greater impacts on water and sediment discharges than lava-flow emplacement. Geo-morphic responses to such disturbances can extend far downstream, persist for decades, and be hazardous. The severity of disturbances to a drainage basin is a function of the specific volcanic process acting, as well as distance from the volcano and magnitude of the eruption. Postdisturbance unit-area sediment yields are among the world's highest; such yields commonly result in abundant redeposition of sand and gravel in distal river reaches, which causes severe channel aggradation and instability. Response to volcanic disturbance can result in socioeconomic consequences more damaging than the direct impacts of the eruption itself.
Bone Morphogenetic Proteins as Regulators of Iron Metabolism
Authors: Parrow Nermi L. , Fleming Robert E.
Published: June 2014

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-beta (TGF-β) superfamily of signaling molecules. In addition to protean roles in embryonic development, germ-line specification, and cellular differentiation, a central role in iron homeostasis has recently been demonstrated for certain BMPs. Specifically, BMP6 serves to relate hepatic iron stores to the hepatocellular expression of the iron-regulatory hormone hepcidin. This regulation occurs via cellular SMAD-signaling molecules and is strongly modulated by the BMP coreceptor hemojuvelin (HJV). Mutations in certain genes influencing signaling to hepcidin via the BMP/SMAD pathway are associated with human disorders of iron metabolism, such as hereditary hemochromatosis and iron-refractory iron-deficiency anemia. Evidence suggests that signals in addition to iron stores influence hepcidin expression via the BMP/SMAD pathway. This review summarizes the details of BMP/SMAD signaling, with a particular focus on its role in iron homeostasis and iron-related diseases.
Induced Systemic Resistance by Beneficial Microbes
Authors: Pieterse Corné M.J. , Zamioudis Christos , Berendsen Roeland L. , Weller David M. , Van Wees Saskia C.M. , Bakker Peter A.H.M.
Published: June 2014

Beneficial microbes in the microbiome of plant roots improve plant health. Induced systemic resistance (ISR) emerged as an important mechanism by which selected plant growth–promoting bacteria and fungi in the rhizosphere prime the whole plant body for enhanced defense against a broad range of pathogens and insect herbivores. A wide variety of root-associated mutualists, including Pseudomonas, Bacillus, Trichoderma, and mycorrhiza species sensitize the plant immune system for enhanced defense without directly activating costly defenses. This review focuses on molecular processes at the interface between plant roots and ISR-eliciting mutualists, and on the progress in our understanding of ISR signaling and systemic defense priming. The central role of the root-specific transcription factor MYB72 in the onset of ISR and the role of phytohormones and defense regulatory proteins in the expression of ISR in aboveground plant parts are highlighted. Finally, the ecological function of ISR-inducing microbes in the root microbiome is discussed.
Speciation in Fungal and Oomycete Plant Pathogens
Authors: Restrepo Silvia , Tabima Javier F. , Mideros Maria F. , Grünwald Niklaus J. , Matute Daniel R.
Published: June 2014

The process of speciation, by definition, involves evolution of one or more reproductive isolating mechanisms that split a single species into two that can no longer interbreed. Determination of which processes are responsible for speciation is important yet challenging. Several studies have proposed that speciation in pathogens is heavily influenced by host-pathogen dynamics and that traits that mediate such interactions (e.g., host mobility, reproductive mode of the pathogen, complexity of the life cycle, and host specificity) must lead to reproductive isolation and ultimately affect speciation rates. In this review, we summarize the main evolutionary processes that lead to speciation of fungal and oomycete plant pathogens and provide an outline of how speciation can be studied rigorously, including novel genetic/genomic developments.
The Activation and Suppression of Plant Innate Immunity by Parasitic Nematodes
Authors: Goverse Aska , Smant Geert
Published: June 2014

Plant-parasitic nematodes engage in prolonged and intimate relationships with their host plants, often involving complex alterations in host cell morphology and function. It is puzzling how nematodes can achieve this, seemingly without activating the innate immune system of their hosts. Secretions released by infective juvenile nematodes are thought to be crucial for host invasion, for nematode migration inside plants, and for feeding on host cells. In the past, much of the research focused on the manipulation of developmental pathways in host plants by plant-parasitic nematodes. However, recent findings demonstrate that plant-parasitic nematodes also deliver effectors into the apoplast and cytoplasm of host cells to suppress plant defense responses. In this review, we describe the current insights in the molecular and cellular mechanisms underlying the activation and suppression of host innate immunity by plant-parasitic nematodes along seven critical evolutionary and developmental transitions in plant parasitism.
Measurement Equivalence in Cross-National Research
Authors: Davidov Eldad , Meuleman Bart , Cieciuch Jan , Schmidt Peter , Billiet Jaak
Published: June 2014

Determining whether people in certain countries score differently in measurements of interest or whether concepts relate differently to each other across nations can indisputably assist in testing theories and advancing our sociological knowledge. However, meaningful comparisons of means or relationships between constructs within and across nations require equivalent measurements of these constructs. This is especially true for subjective attributes such as values, attitudes, opinions, or behavior. In this review, we first discuss the concept of cross-group measurement equivalence, look at possible sources of nonequivalence, and suggest ways to prevent it. Next, we examine the social science methodological literature for ways to empirically test for measurement equivalence. Finally, we consider what may be done when equivalence is not supported by the data and conclude with a review of recent developments that offer exciting directions and solutions for future research in cross-national measurement equivalence assessment.
Role of anion exchangers in Cl− and HCO3− secretion by the human airway epithelial cell line Calu-3
Authors: Kim Dusik , Kim Juyeon , Burghardt Beáta , Best Len , Steward Martin C.
Published: June 2014

Despite the importance of airway surface liquid pH in the lung's defenses against infection, the mechanism of airway HCO3− secretion remains unclear. Our aim was to assess the contribution of apical and basolateral Cl−/HCO3− exchangers to Cl− and HCO3− transport in the Calu-3 cell line, derived from human airway submucosal glands. Changes in intracellular pH (pHi) were measured following substitution of Cl− with gluconate. Apical Cl− substitution led to an alkalinization in forskolin-stimulated cells, indicative of Cl−/HCO3− exchange. This was unaffected by the anion exchange inhibitor DIDS but inhibited by the CFTR blocker CFTRinh-172, suggesting that the HCO3− influx might occur via CFTR, rather than a solute carrier family 26 (SLC26) exchanger, as recently proposed. The anion selectivity of the recovery process more closely resembled that of CFTR than an SLC26 exchanger, and quantitative RT-PCR showed only low levels of SLC26 exchanger transcripts relative to CFTR and anion exchanger 2 (AE2). For pHi to rise to observed values (∼7.8) through HCO3− entry via CFTR, the apical membrane potential must reverse to at least +20 mV following Cl− substitution; this was confirmed by perforated-patch recordings. Substitution of basolateral Cl− evoked a DIDS-sensitive alkalinization, attributed to Cl−/HCO3− exchange via AE2. This appeared to be abolished in forskolin-stimulated cells but was unmasked by blocking apical efflux of HCO3− via CFTR. We conclude that Calu-3 cells secrete HCO3− predominantly via CFTR, and, contrary to previous reports, the basolateral anion exchanger AE2 remains active during stimulation, providing an important pathway for basolateral Cl− uptake.
Cystic fibrosis transmembrane conductance regulator dysfunction in VIP knockout mice
Authors: Alcolado Nicole G. , Conrad Dustin J. , Poroca Diogo , Li Mansong , Alshafie Walaa , Chappe Frederic G. , Pelis Ryan M. , Anini Younes , Xu Zhaolin , Hamidi Sayyed , Said Sami I. , Chappe Valerie M.
Published: June 2014

Vasoactive intestinal peptide (VIP), a neuropeptide, controls multiple functions in exocrine tissues, including inflammation, and relaxation of airway and vascular smooth muscles, and regulates CFTR-dependent secretion, which contributes to mucus hydration and local innate defense of the lung. We had previously reported that VIP stimulates the VPAC1 receptor, PKCϵ signaling cascade, and increases CFTR stability and function at the apical membrane of airway epithelial cells by reducing its internalization rate. Moreover, prolonged VIP stimulation corrects the molecular defects associated with F508del, the most common CFTR mutation responsible for the genetic disease cystic fibrosis. In the present study, we have examined the impact of the absence of VIP on CFTR maturation, cellular localization, and function in vivo using VIP knockout mice. We have conducted pathological assessments and detected signs of lung and intestinal disease. Immunodetection methods have shown that the absence of VIP results in CFTR intracellular retention despite normal expression and maturation levels. A subsequent loss of CFTR-dependent chloride current was measured in functional assays with Ussing chamber analysis of the small intestine ex vivo, creating a cystic fibrosis-like condition. Interestingly, intraperitoneal administration of VIP corrected tissue abnormalities, close to the wild-type phenotype, as well as associated defects in the vital CFTR protein. The results show in vivo a primary role for VIP chronic exposure in CFTR membrane stability and function and confirm in vitro data.
Inhibition of Wnt/β-catenin signaling promotes epithelial differentiation of mesenchymal stem cells and repairs bleomycin-induced lung injury
Authors: Wang Cong , Zhu Huiming , Sun Zhaorui , Xiang Zou , Ge Yuanyuan , Ni Can , Luo Zhaowen , Qian Weiping , Han Xiaodong
Published: June 2014

Idiopathic pulmonary fibrosis is a progressive lung disorder of unknown etiology. Previous studies have shown that aberrant activation of the Wnt/β-catenin signaling cascade occurs in lungs of patients with idiopathic pulmonary fibrosis. Given the important roles of the Wnt/β-catenin signaling pathway in the development of pulmonary fibrosis, we targeted this pathway for the intervention of pulmonary fibrosis with XAV939, a small molecule that specifically inhibits Tankyrase 1/2, eventually leading to the degradation of β-catenin and suppression of the Wnt/β-catenin signaling pathway. Our results demonstrated that XAV939 significantly inhibited the activation of Wnt/β-catenin signaling and attenuated bleomycin-induced lung fibrosis in mice, and thus improved the survival of mice with lung injury. Interestingly, previous investigations have confirmed that endogenous and exogenous mesenchymal stem cells could be recruited to the injured lung, although the exact effects of these cells are debatable. To determine the effect of Wnt/β-catenin signaling in the epithelial differentiation of bone marrow-derived mesenchymal stem cells (BM-MSCs), we established a coculture system that contains BM-MSCs and alveolar type II epithelial cells. The in vitro experiments demonstrated that XAV939 could promote the differentiation of BM-MSCs into an epithelium-like phenotype in the coculture system. We also found that XAV939 could inhibit the proliferation and myofibroblast differentiation of NIH/3T3 fibroblasts. This work supports that inhibition of the Wnt/β-catenin signaling pathway may be exploited for the treatment of idiopathic pulmonary fibrosis for which effective treatment strategies are still lacking.
Blood flow does not redistribute from respiratory to leg muscles during exercise breathing heliox or oxygen in COPD
Authors: Louvaris Zafeiris , Vogiatzis Ioannis , Aliverti Andrea , Habazettl Helmut , Wagner Harrieth , Wagner Peter , Zakynthinos Spyros
Published: June 2014

In patients with chronic obstructive pulmonary disease (COPD), one of the proposed mechanisms for improving exercise tolerance, when work of breathing is experimentally reduced, is redistribution of blood flow from the respiratory to locomotor muscles. Accordingly, we investigated whether exercise capacity is improved on the basis of blood flow redistribution during exercise while subjects are breathing heliox (designed to primarily reduce the mechanical work of breathing) and during exercise with oxygen supplementation (designed to primarily enhance systemic oxygen delivery but also to reduce mechanical work of breathing). Intercostal, abdominal, and vastus lateralis muscle perfusion were simultaneously measured in 10 patients with COPD (forced expiratory volume in 1 s: 46 ± 12% predicted) by near-infrared spectroscopy using indocyanine green dye. Measurements were performed during constant-load exercise at 75% of peak capacity to exhaustion while subjects breathed room air and, then at the same workload, breathed either normoxic heliox (helium 79% and oxygen 21%) or 100% oxygen, the latter two in balanced order. Times to exhaustion while breathing heliox and oxygen did not differ (659 ± 42 s with heliox and 696 ± 48 s with 100% O2), but both exceeded that on room air (406 ± 36 s, P < 0.001). At exhaustion, intercostal and abdominal muscle blood flow during heliox (9.5 ± 0.6 and 8.0 ± 0.7 ml · min−1·100 g−1, respectively) was greater compared with room air (6.8 ± 0.5 and 6.0 ± 0.5 ml·min−1·100 g·, respectively; P < 0.05), whereas neither intercostal nor abdominal muscle blood flow differed between oxygen and air breathing. Quadriceps muscle blood flow was also greater with heliox compared with room air (30.2 ± 4.1 vs. 25.4 ± 2.9 ml·min−1·100 g−1; P < 0.01) but did not differ between air and oxygen breathing. Although our findings confirm that reducing the burden on respiration by heliox or oxygen breathing prolongs time to exhaustion (at 75% of maximal capacity) in patients with COPD, they do not support the hypothesis that redistribution of blood flow from the respiratory to locomotor muscles is the explanation.
Rapid prediction of biomechanical costs during action decisions
Authors: Cos Ignasi , Duque Julie , Cisek Paul
Published: June 2014

When given a choice between actions that yield the same reward, we tend to prefer the one that requires the least effort. Recent studies have shown that humans are remarkably accurate at evaluating the effort of potential reaching actions and can predict the subtle energetic demand caused by the nonisotropic biomechanical properties of the arm. In the present study, we investigated the time course over which such information is computed and comes to influence decisions. Two independent approaches were used. First, subjects performed a reach decision task in which the time interval for deciding between two candidate reaching actions was varied from 200 to 800 ms. Second, we measured motor-evoked potential (MEPs) to single-pulse transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) to probe the evolving decision at different times after stimulus presentation. Both studies yielded a consistent conclusion: that a prediction of the effort associated with candidate movements is computed very quickly and influences decisions within 200 ms after presentation of the candidate actions. Furthermore, whereas the MEPs measured 150 ms after stimulus presentation were well correlated with the choices that subjects ultimately made, later in the trial the MEP amplitudes were primarily related to the muscular requirements of the chosen movement. This suggests that corticospinal excitability (CSE) initially reflects a competition between candidate actions and later changes to reflect the processes of preparing to implement the winning action choice.
Corticospinal excitability of the biceps brachii is higher during arm cycling than an intensity-matched tonic contraction
Authors: Forman Davis , Raj Amita , Button Duane C. , Power Kevin E.
Published: June 2014

Human studies have not assessed corticospinal excitability of an upper-limb prime mover during arm cycling. The purpose of the present study was to determine whether supraspinal and/or spinal motoneuron excitability of the biceps brachii was different between arm cycling and an intensity-matched tonic contraction. We hypothesized that spinal motoneuron excitability would be higher during arm cycling than an intensity-matched tonic contraction. Supraspinal and spinal motoneuron excitability were assessed using transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid electrical stimulation (TMES) of the corticospinal tract, respectively. TMS-induced motor-evoked potentials (MEPs) and TMES-induced cervicomedullary-evoked potentials (CMEPs) were assessed at three separate positions (3, 6, and 12 o'clock relative to a clock face) during arm cycling and an intensity-matched tonic contraction. MEP amplitudes were 7.2 and 8.8% maximum amplitude of the compound muscle action potential (Mmax) larger during arm cycling compared with a tonic contraction at the 3 ( P < 0.001) and 6 o'clock ( P < 0.001) positions, respectively. There was no difference between tasks during elbow extension (12 o'clock). CMEP amplitudes were 5.2% Mmax larger during arm cycling compared with a tonic contraction at the 3 o'clock position ( P < 0.001) with no differences seen at midflexion (6 o'clock) or extension (12 o'clock). The data indicate an increase in the excitability of corticospinal neurons, which ultimately project to biceps brachii during the elbow flexion portion of arm cycling, and increased spinal motoneuron excitability at the onset of elbow flexion during arm cycling. We conclude that supraspinal and spinal motoneuron excitability are phase- and task-dependent.
Disrupting information coding via block of 4-AP-sensitive potassium channels
Authors: Padmanabhan Krishnan , Urban Nathaniel N.
Published: June 2014

Recent interest has emerged on the role of intrinsic biophysical diversity in neuronal coding. An important question in neurophysiology is understanding which voltage-gated ion channels are responsible for this diversity and how variable expression or activity of one class of ion channels across neurons of a single type affects they way populations carry information. In mitral cells in the olfactory bulb of mice, we found that biophysical diversity was conferred in part by 4-aminopyridine (4-AP)-sensitive potassium channels and reduced following block of those channels. When populations of mitral cells were stimulated with identical inputs, the diversity exhibited in their output spike patterns reduced with the addition of 4-AP, decreasing the stimulus information carried by ensembles of 15 neurons from 437 ± 15 to 397 ± 19 bits/s. Decreases in information were due to reduction in the diversity of population spike patterns generated in response to different features of the stimulus, suggesting that the coding capacity of a population can be altered by changes in the function of single ion channel types.
Design and Fabrication of Diffractive Light-Collecting Microoptical Device with 1D and 2D Lamellar Grating Structures
Authors: Lee ChaBum
Published: June 2014

This paper presents the optimal design method of diffractive light-collecting microoptical device and its fabrication method by E-beam lithography, fast atom beam etching, and hot-embossing processes. The light-collecting device proposed in the paper is comprised of 9 (3 × 3) blocks of optical elements: 4 blocks of 1D lamellar grating structures, 4 blocks of 2D lamellar grating structures, and a single block of nonpatterned element at the center, which acts for lens to be able to collect the diffracted and transmitted lights from the lamellar grating structures into the focus area. The overall size of the light-collecting device is 300 × 300 μm2, and the size of each block was practically designed as 100 × 100 μm2. The performance of 1D and 2D lamellar grating structures was characterized in terms of diffraction efficiency and diffraction angle using a rigorous coupled-wave
analysis (RCWA) method, and those geometric parameters, depth, pitch, and orientation, were optimized to achieve a high light-collecting efficiency. The master molds for the optimized structures were fabricated on Si substrate by E-beam lithography and fast atom beam etching processes. The 100 μm thick patterned polymethyl methacrylate (PMMA) film was then replicated by a hot-embossing process. As a result, the patterned PMMA film collected 63.0% more incident light than a nonpatterned one.
Feedback Linearisation for Nonlinear Vibration Problems
Authors: Jiffri S. , Paoletti P. , Cooper J. E. , Mottershead J. E.
Published: June 2014

Feedback linearisation is a well-known technique in the controls community but has not been widely taken up in the vibrations community. It has the advantage of linearising nonlinear system models, thereby enabling the avoidance of the complicated mathematics associated with nonlinear problems. A particular and common class of problems is considered, where the nonlinearity is present in a system parameter and a formulation in terms of the usual second-order matrix differential equation is presented. The classical texts all cast the feedback linearisation problem in first-order form, requiring repeated differentiation of the output, usually presented in the Lie algebra notation. This becomes unnecessary when using second-order matrix equations of the problem class considered herein. Analysis is presented for the general multidegree of freedom system for those cases when a full set of sensors and actuators is available at every degree of freedom and when the number of sensors and actuators is fewer than the number of degrees of freedom. Adaptive feedback linearisation is used to address the problem of nonlinearity that is not known precisely. The theory is illustrated by means of a three-degree-of-freedom nonlinear aeroelastic model, with results demonstrating the effectiveness of the method in suppressing flutter.
Novel Clinical and Diagnostic Aspects of Antineutrophil Cytoplasmic Antibodies
Authors: Schulte-Pelkum Johannes , Radice Antonella , Norman Gary L. , Lόpez Hoyos Marcos , Lakos Gabriella , Buchner Carol , Musset Lucile , Miyara Makoto , Stinton Laura , Mahler Michael
Published: June 2014

Antineutrophil cytoplasmic antibodies (ANCA) are the serological hallmark of some idiopathic systemic vasculitides. Besides the investigation of ANCA-associated vasculitis (AAV) and constant effort for a standardized nomenclature and classification of the AAV, a main focus of research during the last few years has been to constantly improve the performance of enzyme immunoassays. With the latest so called third generation ELISA, this goal seemed to be fulfilled. The International Consensus Statement on Testing and Reporting of ANCA gave recommendations for standardized strategies for the serological diagnosis of ANCA. New developments now target the system immanent drawbacks of the respective diagnostic methods, be it the need for batching and the long time to result for ELISA, or the high likelihood of error and subjectivity of indirect immunofluorescence (IIF). Random access technology and multiplexing for solid phase assays as well as digital imaging for IIF are tools which may help to expedite and simplify routine diagnostics in the lab and in emergency settings. Recent findings indicate that PR3-ANCA have clinical utility beyond the diagnosis of AAV. PR3-ANCA can also serve as an aid for the differentiation between ulcerative colitis (UC) and Crohn’s disease (CrD) and the stratification of UC patients. This review provides a detailed review of what is known about ANCA and highlights the latest research and state-of-the-art developments in this area.
Computing Singular Points of Projective Plane Algebraic Curves by Homotopy Continuation Methods
Authors: Luo Zhongxuan , Feng Erbao , Zhang Jielin
Published: June 2014

We present an algorithm that computes the singular points of projective plane algebraic curves and determines their multiplicities and characters. The feasibility of the algorithm is analyzed. We prove that the algorithm has the polynomial time complexity on the degree of the algebraic curve. The algorithm involves the combined applications of homotopy continuation methods and a method of root computation of univariate polynomials. Numerical experiments show that our algorithm is feasible and efficient.
A Source Aware Scheduling Algorithm for Time-Optimal Convergecast
Authors: Zhao Jing , Qin Yajuan , Yang Dong , Rao Ying
Published: June 2014

Most applications of industrial wireless sensor networks (IWSNs) should converge process data generated by each node to the central manager. The data collection operation results in an important communication primitive referred to as convergecast. Convergecast is a many-to-one communication paradigm as a critical functionality deployed for industrial monitoring and control. Delaying of process data may degrade the overall control performance and even lead to the malfunction of industrial applications. Therefore, timeslot and channel resources should be scheduled efficiently for real-time communication. This paper is interested in determining a TDMA schedule that minimizes the number of timeslots and completes convergecast with a limited number of channels. In order to achieve the lower bound derived by theoretical analysis, we proposed a source aware scheduling algorithm for general network. For IWSNs with a fixed number of available channels, we present a source aware scheduling algorithm with constrained channel. According to simulation results, we demonstrate that the performance of our algorithm is close to the lower bound on latency with a limited number of channels. Our algorithm is also scalable for schedules with multiple packets and specific transmission latency of a single packet.
Differential Fault Attack on KASUMI Cipher Used in GSM Telephony
Authors: Wang Zongyue , Dong Xiaoyang , Jia Keting , Zhao Jingyuan
Published: June 2014

The confidentiality of GSM cellular telephony depends on the security of A5 family of cryptosystems. As an algorithm in this family survived from cryptanalysis, A5/3 is based on the block cipher KASUMI. This paper describes a novel differential fault attack on KAUSMI with a 64‐bit key. Taking advantage of some mathematical observations on the FL, FO functions, and key schedule, only one 16‐bit word fault is required to recover all information of the 64‐bit key. The time complexity is only 232 encryptions. We have practically simulated the attack on a PC which takes only a few minutes to recover all the key bits. The simulation also experimentally verifies the correctness and complexity.
The Role of microRNAs in the Regulation of Apoptosis in Lung Cancer and Its Application in Cancer Treatment
Authors: Othman Norahayu , Nagoor Noor Hasima
Published: June 2014

Lung cancer remains to be one of the most common and serious types of cancer worldwide. While treatment is available, the survival rate of this cancer is still critically low due to late stage diagnosis and high frequency of drug resistance, thus highlighting the pressing need for a greater understanding of the molecular mechanisms involved in lung carcinogenesis. Studies in the past years have evidenced that microRNAs (miRNAs) are critical players in the regulation of various biological functions, including apoptosis, which is a process frequently evaded in cancer progression. Recently, miRNAs were demonstrated to possess proapoptotic or antiapoptotic abilities through the targeting of oncogenes or tumor suppressor genes. This review examines the involvement of miRNAs in the apoptotic process of lung cancer and will also touch on the promising evidence supporting the role of miRNAs in regulating sensitivity to anticancer treatment.
Small Intestinal Amyloidosis: A Rare Cause of Diverticular Disease
Authors: Groisman Gabriel M. , Cohen Hector I.
Published: June 2014

Systemic amyloidosis frequently involves the small intestine. However, its association with diverticular disease has been seldom reported to date. To draw attention to this rare but potentially harmful association, we herein present an additional case of small bowel diverticular disease associated with amyloidosis.
Three-Step Block Method for Solving Nonlinear Boundary Value Problems
Authors: See Phang Pei , Abdul Majid Zanariah , Suleiman Mohamed
Published: June 2014

We propose a three-step block method of Adam’s type to solve nonlinear second-order two-point boundary value problems of Dirichlet type and Neumann type directly. We also extend this method to solve the system of second-order boundary value problems which have the same or different two boundary conditions. The method will be implemented in predictor corrector mode and obtain the approximate solutions at three points simultaneously using variable step size strategy. The proposed block method will be adapted with multiple shooting techniques via the three-step iterative method. The boundary value problem will be solved without reducing to first-order equations. The numerical results are presented to demonstrate the effectiveness of the proposed method.
Antibacterial and Antifungal Effect of 405 nm Monochromatic Laser on Endodontopathogenic Microorganisms
Authors: Imamura Takahiro , Tatehara Seiko , Takebe Yusuke , Tokuyama Reiko , Ohshima Tomoko , Maeda Nobuko , Satomura Kazuhito
Published: June 2014

The purpose of this study is to evaluate the usefulness of 405 nm monochromatic laser irradiation as an alternative management for prevention and/or treatment of endodontic infections. A monochromatic laser-emitting device equipped with a 405-nm laser diode was developed. Using this device, the effect of 405 nm laser irradiation on the growth ofPorphyromonas gingivalis, Prevotella intermedia, Enterococcus faecalis, andCandida albicans, which are microorganisms associated with persistent endodontic infections, was evaluated by viable colony counting. As a result, the irradiation with a 405 nm laser had a significant bactericidal/fungicidal effect onP. gingivalis, P. intermedia, andC. albicans, whereas the growth ofE. faecaliswas not affected by the irradiation. The inhibition rate inP. gingivalisandP. intermediawas ~60% and ~80%, respectively, following irradiation at 0.2 W for 300 sec. The inhibition rate inC. albicanswas ~90% following irradiation at 0.2 W for 1200 sec. These results indicate that 405 nm monochromatic laser irradiation exerts a bactericidal/fungicidal effect on these microorganisms. The present study clearly demonstrates that 405 nm laser irradiation is a promising alternative management strategy for prevention and/or treatment of endodontic infections.
Almost Sure andLpConvergence of Split-Step Backward Euler Method for Stochastic Delay Differential Equation
Authors: Guo Qian , Tao Xueyin
Published: June 2014

The convergence of the split-step backward Euler (SSBE) method applied to stochastic differential equation with variable delay is proven inLp-sense. Almost sure convergence is derived from theLpconvergence by Chebyshev’s inequality and the Borel-Cantelli lemma; meanwhile, the convergence rate is obtained.