bluuebunny/crossref_metadata_2025 huggingface dataset:
Anatomical location of arterial and venous lines significantly affects motor performance in rats
Authors: OHAYON Sharon , GRUENBAUM Shaun E. , ARTRU Alan A. , BOYKO Matthew , GRUENBAUM Benjamin F. , DUBILET Michael , LEIBOWITZ Akiva , SHAPIRA Yoram , TEICHBERG Vivian I. , ZLOTNIK Alexander
Published: April 2012

Several motor‐function scales have been developed to assess neurological function in animal models of stroke, subarachnoid hemorrhage and closed head injury. We hypothesize that the location of arterial and venous catheters, even in the absence of brain injury, may impact rats' motor performance. Our study examined the effect of catheter location, rate of infection and the time required for catheter placement. We further describe an original technique of tail artery cannulation without exposure of the artery. Sixty‐one rats were anesthetized and randomly assigned to one of seven groups, including no catheter, tail artery or artery + vein catheters, or femoral artery or artery + vein catheters. A neurological severity score (NSS) was determined at 1 h, 24 h and 48 h after surgical preparation or catheter placement. NSS at 1 h after placement of unilateral and bilateral femoral catheters was higher than the NSS observed at 1 h after placement of tail arterial and venous catheters (P < 0.01). The NSS also was higher at 24 h in the bilateral femoral catheter groups as compared with the tail catheter groups (P < 0.05). There were no differences in the NSS observed between the groups that had tail catheters and the sham group at 1 h, 24 h or 48 h. Infection rate at the site of catheter placement and the time required for catheter placement was also higher in the femoral catheter groups (P < 0.001). Thus, we propose that the line location may bias a study's results and lead to deceptive interpretations of neurological assessment following rat head injury. Compared to femoral vessels, tail blood vessels are preferable locations for lines placement.
Debris discs at centimetre wavelengths: planetesimal populations in young extrasolar Kuiper belts
Authors: Greaves J. S. , Hales A. S. , Mason B. S. , Matthews B. C.
Published: April 2012

Two luminous debris discs around 100 Myr old have been searched for 1 cm dust emission, to a depth three times greater than in any such previous study. Very low limits were set towards both HD 377 and HD 104860 (noise levels of 12–14 Jy), extending the spectral range from 70 m to 3 mm where cool dust has previously been sought. The almost-identical fluxes of the two systems were merged into an average spectral energy distribution, which was then fitted using a distribution of grain sizes. The canonical infinite collisional cascade, with numbers of particles n(D) ∝ D−3.5 for diameter D, overpredicts the 1-cm flux, which should have been detected at over 3σ for the merged system. Preferred solutions have truncated grain populations with largest particles around 1.5–4 mm in diameter, and slightly flatter distributions, up to n(D) ∝ D−3.1. The lack of cm-sized and larger particles is reminiscent of the similar deficit inferred around comets from spacecraft encounters. Such departures from simple power-law distributions of particles have been predicted in recent models where some size regimes are more readily broken up than others. A deficit of cm-scale particles can explain the fits we obtain, and reduces the total masses inferred for the comet belts of these stars.
One step beyond: the excursion set approach with correlated steps
Authors: Musso Marcello , Sheth Ravi K.
Published: April 2012

We provide a simple formula that accurately approximates the first crossing distribution of barriers having a wide variety of shapes, by random walks with a wide range of correlations between steps. Special cases of it are useful for estimating halo abundances, evolution and bias, as well as the non-linear counts in cells distribution. We discuss how it can be extended to allow for the dependence of the barrier on quantities other than overdensity, to construct an excursion set model for peaks, and to show why assembly and scale-dependent bias are generic even at the linear level.
Syntheses and Structure–Activity Relationships of Seven Manganese–Salen Derivatives as Anti‐amyloidogenic and Fibril‐destabilizing Agents Against Hen Egg‐white Lysozyme Aggregation
Authors: Bahramikia Seifollah , Yazdanparast Razieh , Gheysarzadeh Ali
Published: April 2012

Accumulation of intra‐ and/or extracellular misfolded proteins as amyloid fibrils is a key hallmark in more than 20 amyloid‐related diseases. In that respect, blocking or reversing amyloid aggregation via the use of small compounds is considered as two useful approaches in hampering the development of these diseases. In this research, we have studied the ability of different manganese–salen derivatives to inhibit amyloid self‐assembly as well as to dissolve amyloid aggregates of hen egg‐white lysozyme, as an in vitro model system, with the aim of investigating their structure–activity relationships. By coupling several techniques such as thioflavin T and anilinonaphthalene‐8‐sulfonic acid fluorescence, congo red absorbance, far‐UV circular dichroism, and transmission electron microscopy, we demonstrated that all compounds possessed anti‐amyloidogenic activities and were capable of dispersing the fibrillar aggregates. In addition, MTT assay of the treated SK‐N‐MC cells with the preformed fibrils formed in the presence of compounds at a drug‐to‐protein molar ratio of 5:1, indicated a significant increase in the viability of cells, compared to the fibrils formed in the absence of each of the compounds. Our spectroscopy, electron microscopy, and cellular studies indicated that EUK‐15, with a methoxy group at the para position (group R5), had higher activity to either inhibit or disrupt the β‐sheet structures relative to other compounds. On the basis of these results, it can be concluded that in addition to aromatic rings of each of the derivatives, the type and position of the side group(s) contribute to lower lysozyme fibril accumulation.
Secularism in the Indian Context
Authors: Das Acevedo Deepa
Published: April 2012

Indian constitutional framers sought to tie their new state to ideas of modernity and liberalism by creating a government that would ensure citizens' rights while also creating the conditions for democratic citizenship. Balancing these two goals has been particularly challenging with regard to religion, as exemplified by the emergence of a peculiarly Indian understanding of secularism which requires the nonestablishment of religion but not the separation of religion and state. Supporters argue that this brand of secularism is best suited to the particular social and historical circumstances of independent India. This article suggests that the desire to separate religion and state is integral to any understanding of secularism and that, consequently, the Indian state neither is nor was meant to be secular. However, Indian secularists correctly identify the Indian state's distinctive approach to religion-state relations as appropriate to the Indian context and in keeping with India's constitutional goals.
Origin Myths, Contracts, and the Hunt for Pari Passu
Authors: Weidemaier Mark , Scott Robert , Gulati Mitu
Published: April 2012

We use interviews with corporate lawyers and a data set of contracts to explore an elite area of legal practice: sovereign bond lending. Sovereign debt lawyers work at prestigious global law firms, yet the contracts they produce include some terms that defy explanation. Lawyers often account for the existence of these terms through origin myths. Focusing on one contract term, the pari passu clause, we explore two puzzling aspects of these myths. First, we demonstrate that the myths are inaccurate as to both the clause's origin and the role of lawyers in contract drafting. Second, the myths often are unflattering, inaccurately portraying lawyers as engaged in little more than rote copying. We probe this disjuncture between the myths and lawyers' actual practices and explore why contracts origin myths might hold such appeal for this elite segment of the bar.
Proton‐based chemoradiation for synchronous bilateral non‐small‐cell lung cancers: A case report
Authors: Shi Wenyin , Nichols, Jr Romaine C. , Flampouri Stella , Li Zuofeng , Hsi Wen , Huh Soon , Ho Meng Wei , Henderson Randall H. , Mendenhall Nancy P. , Hoppe Bradford S.
Published: April 2012

In this case report, we present the history and treatment of a 70‐year‐old man with synchronous bilateral non‐small‐cell lung cancers with proton‐beam radiation. Surgical treatment was not feasible and optimized photon intensity‐modulated radiotherapy (IMRT) to the primary tumors would have resulted in unacceptably high normal‐tissue exposures. Proton‐beam radiation enabled radiation dose escalation and concurrent chemotherapy while maintaining normal‐tissue tolerance.
The Relationship between Body Dysmorphic Disorder Behaviors and the Acquired Capability for Suicide
Authors: Witte Tracy K. , Didie Elizabeth R. , Menard William , Phillips Katharine A.
Published: April 2012

In a sample of 200 individuals diagnosed with body dysmorphic disorder (BDD), we utilized the interpersonal–psychological theory for suicide as a framework to examine BDD behaviors that might be associated with suicide risk, insofar as they might increase the acquired capability for suicide. We predicted that physically painful BDD behaviors (e.g., cosmetic surgery, restrictive eating) would be associated with suicide attempts but not suicide‐related ideation because these behaviors increase capability for, but not thoughts about, suicide. Our hypothesis was partially confirmed, as BDD‐related restrictive food intake was associated with suicide attempts (but not suicide‐related ideation) even after controlling for numerous covariates.
Estimating adult sex ratios from bird mist netting data
Authors: Amrhein Valentin , Scaar Bertrand , Baumann Marc , Minéry Nicolas , Binnert Jean‐Paul , Korner‐Nievergelt Fränzi
Published: April 2012

1. It is increasingly acknowledged that skewed adult sex ratios (ASRs) may play an important role in ecology, evolution and conservation of animals.

2. In birds, published estimates on ASRs mostly rely on mist netting data. However, previous studies suggested that mist nets or other trap types provide biased estimates on sex ratios, with males being more susceptible to capture than females.

3. We used data from a Constant Effort Site ringing scheme to show how sex ratios that are corrected for sex‐ and year‐specific capture probabilities can be directly estimated by applying capture–recapture analysis, for example, in a Bayesian framework.

4. When capture data were pooled from the 19 years of study, we found that in the blackbird (Turdus merula) and the blackcap (Sylvia atricapilla), the observed proportions of males were 57% and 55%, respectively. However, when the observed annual proportions of males were corrected for the sex‐specific capture probabilities, the proportions of males did not clearly differ from 50% in most study years, and thus, the apparent male‐bias in the ASRs almost completely disappeared.

5. We propose that published estimates on ASRs in birds should be re‐evaluated if based solely on observed sex ratios from mist netting studies.

6. We further propose that data from national bird ringing schemes and in particular from Constant Effort Site ringing programs can provide valuable information on ASRs, if analysed using capture–recapture models. We discuss important assumptions of those models; for example, movements that may differ between sexes should be taken into account, as well as the occurrence of transient individuals that do not hold breeding territories within a study site.
Coupling Dynamic Model and Control of Chatter in Cold Rolling
Authors: Yang Xu , Tong Chao-nan
Published: April 2012

The dynamic model of 4-h mill, which couples with the rolling process model, the mill roll stand structure model, and the hydraulic servo system model, is built by analyzing the vibration process of cold rolling. By linearization, the multiple input multiple output linear transfer function matrix model of single stand 4-h cold mill system is obtained. With the consideration of strip quality, the model of strip thickness control system is established in a simplified form. Meanwhile, the robust controller based on quantitative feedback theory is designed for the gauge control model. A comparison with PID controller shows that the controller has better disturbance attenuation performance for parameter uncertainty and external disturbance.
Highly Reduced Lumped Parameter Models Representing Impedance Functions at the Interface of One-Dimensional Viscoelastic Continua
Authors: Saitoh Masato
Published: April 2012

In recent dynamic problems dealing with high-frequency excitations, such as ultrasonic vibrations, a proper representation of rods transmitting kinetic energy from the interface attached to the vibrating system to the other end is strongly demanded for effectively reducing computational time and domain. A highly reduced lumped parameter model that properly simulates the dynamic characteristics of a uniform, isotropic, homogeneous, and viscoelastic rod subjected to excitations at its end is proposed in this paper. The model consists of springs, dashpots, and so called “gyro-mass elements.” The gyro-mass element generates a reaction force proportional to the relative acceleration of the nodes between which it is placed. This model consists of units arranged in series, each unit consisting of a spring, a dashpot, and a gyro-mass element arranged in parallel. A formula is proposed for determining the properties of the elements in the units based on the modal expansion. The results show that a notable reduction of 90% in the degrees of freedom is accomplished with high accuracy by using the proposed model consisting of a set of units associated with modes in a target frequency region and a supplemental unit associated with residual stiffness, which is advantageous for efficient numerical computations in recent dynamic problems.
Machine Tool Condition Monitoring Based on an Adaptive Gaussian Mixture Model
Authors: Yu Jianbo
Published: April 2012

Indirect, online tool wear monitoring is one of the most difficult tasks in the context of industrial machining operation. The challenge is how to construct an effective model that can consistently exemplify the degradation propagation of tool performance (i.e., tool wear) based on a continuous acquisition of multiple sensor signals. This paper proposes an adaptive Gaussian mixture model (AGMM) to provide a comprehensible and robust indication (i.e., Kullback–Leibler (KL) divergence) for quantifying tool performance degradation. Based on dynamic learning rate, parameter updating, and merge and split of Gaussian components, AGMM is capable of online adaptively learning the dynamic changes of tool performance in its full life. Furthermore, the performance changes of tools are quantified by measuring the distance between two density distributions approximated by the AGMM and the baseline GMM trained by the normal data, respectively. Experimental results of its application in a machine tool test demonstrate the effectiveness of the AGMM-based KL-divergence indication for assessment of tool performance degradation.
Statics and Stiffness
Model of Serial-Parallel Manipulator Formed by k Parallel Manipulators Connected in
Series
Authors: Hu Bo , Yu Jingjing , Lu Yi , Sui Chunping , Han Jianda
Published: April 2012

The statics and stiffness model of serial-parallel manipulators (S-PMs) formed by k parallel manipulators (PMs) connected in series is established in this paper. The S-PMs can provide features of both serial manipulators (SMs) and PMs. First, the unified formulae for solving the statics and stiffness of S-PMs are derived. Second, a k(PS + RPS + SPS) S-PM is analyzed to illustrate this model. Finally, an analytic solved example for 5(PS + RPS + SPS) S-PM is given. The established model can offer an essential theoretical basis for S-PMs.
Comparison of Algorithms for Haptic Interaction With Isosurfaces Extracted From Volumetric Datasets
Authors: Rizzi Silvio H. , Luciano Cristian J. , Pat Banerjee P.
Published: April 2012

Combinations of graphics and haptics libraries are used in medical simulations for simultaneous visualization and tactile interaction with complex 3D anatomy models. The minimum frame rate of 1 kHz for haptics rendering makes it a nontrivial problem when dealing with complex and highly detailed polygonal models. Multiple haptics algorithms based on polygonal mesh rendering, volume haptics, and intermediate representation are evaluated in terms of their servoloop rendering time, client thread rendering time, and quality of force feedback. Algorithms include OpenHaptics’ Feedback Buffer and Depth Buffer, GodObject and Ruspini renderers in h3d, chai3d implementation in h3d, ScalarSurfaceFriction mode in Volume Haptics ToolKit (vhtk), and the authors’ intermediate representation algorithm based on volumetric data. The latter, in combination with surface graphics visualization, is found to deliver the best rendering time, to detect all collisions and to provide correct haptic feedback where other algorithms fail.
Topology Optimization for Static Shape Control of Piezoelectric Plates With Penalization on Intermediate Actuation Voltage
Authors: Kang Zhan , Wang Xiaoming , Luo Zhen
Published: April 2012

This paper investigates the simultaneous optimal distribution of structural material and trilevel actuation voltage for static shape control applications. In this optimal design problem, the shape error between the actuated and the desired shapes is chosen as the objective function. The energy and the material volume are taken as constraints in the optimization problem formulation. The discrete-valued optimization problem is relaxed using element-wise continuous design variables representing the relative material density and the actuation voltage level. Artificial interpolation models which relate the mechanical/piezoelectrical properties of the material and the actuation voltage to the design variables are employed. Therein, power-law penalization functions are used to suppress intermediate values of both the material densities and the control voltage. The sensitivity analysis procedure is discussed, and the design variables are optimized by using the method of moving asymptotes (MMA). Finally, numerical examples are presented to demonstrate the applicability and effectiveness of the proposed method. It is shown that the proposed method is able to yield distinct material distribution and to suppress intermediate actuation voltage values as required.
Chemical and structural study of electrically passivating Al2O3/Si interfaces prepared by atomic layer deposition
Authors: Naumann Volker , Otto Martin , Wehrspohn Ralf B. , Hagendorf Christian
Published: April 2012

Aluminum oxide (Al2O3) layers, prepared by atomic layer deposition (ALD), provide excellent surface passivation properties on crystalline Si surfaces, which are of major importance for photovoltaic applications. Beyond the chemical passivation by reduction of the electronic surface state density, a supportive field effect passivation mechanism emerges at the Al2O3/Si interface. The atomic origin of the fixed negative charges that are responsible for the field effect is currently under discussion. In this contribution, thin layers of Al2O3 with thicknesses ranging from the submonolayer region to several nanometers have been grown on Si substrates by means of thermal ALD. The principle elements of the samples have been quantified by x-ray photoelectron spectroscopy as a function of the film thickness. Changes at the interface upon thermal annealing have been investigated in detail. After the first few ALD cycles an imperfect Al2O3 layer is found together with the formation of an ultrathin SiOx interlayer. Continued deposition leads to stoichiometric Al2O3 growth. Within the first ∼1 nm from the Si interface, additional O (“excess O”), surpassing the Al2O3 and SiO2 stoichiometry, is observed. The excess O does not completely react with the Si surface to SiO2 during thermal annealing. Therefore, interstitial O in near-interface Al2O3 is suggested to provide the fixed negatively charged states.
Quantitative study of focused ultrasound enhanced doxorubicin delivery to prostate tumor in vivo with MRI guidance
Authors: Chen Xiaoming , Cvetkovic Dusica , Ma C.‐M. , Chen Lili
Published: April 2012

Purpose:

The purpose of this study was to investigate the potential of MR‐guided pulsed focused ultrasound (pFUS) for the enhancement of drug uptake in prostate tumorsin vivo using doxorubicin (Dox).

Methods:

An antitumor drug Dox, an orthotopic animal prostate tumor model using human prostate cancer, LNCaP cell line, and a clinical FUS treatment system (InSightec ExAblate 2000) with a 1.5T GE MR scanner were used in this study. First, experiments on a tissue mimic phantom to determine the optimal acoustic power and exposure durations with a 10% duty cycle and a 1 Hz pulse rate were performed. The temperature variation was monitored using real‐time MR thermometry. Second, tumor‐bearing animals were treated with pFUS. There were three groups (n = 8/group): group 1 received pFUS + Dox (10 mg/kg i.v. injection immediately after pFUS exposure), group 2 received Dox only (10 mg/kg i.v. injection), and group 3 was a control. Animals were euthanized 2 h after the pFUS treatment. The Dox concentration in the treated tumors was measured by quantifying fluorescent tracers using a fluorometer. Third, the histological changes of tumors with and without pFUS treatments were evaluated. Finally, experiments were performed to study the spatial drug distribution in tumors after the pFUS treatment, in which two animals received pFUS + Dox, two animals received Dox only, and one animal was used as control. Two hours following the treatment, animals were euthanized and processed. The Dox distribution was determined using a fluorescence microscope.

Results:

Parametric measurements using a tissue phantom showed that the temperature increased with an increasing acoustic power (from 10 to 50 W) or sonication duration (from 10 to 60 s) with a given acoustic frequency of 1 MHz, duty cycle 10%, and pulse rate 1 Hz. A set of ultrasound parameters was identified with which the temperature elevation was less than 5 °C, which was used for nonthermal pFUS sonication. Increased Dox concentration (14.9 ± 2.5 μg/g) was measured in the pFUS‐treated group compared to the Dox‐only group (9.5 ± 1.6 μg/g), indicating an approximate 60% increase withp = 0.05. The results were consistent with the increased spatial drug distributions by fluorescence imaging. Histological analysis showed increased extravasation in pFUS‐treated prostate tumors suggesting increased drug delivery with pFUS.

Conclusions:

The results showed that pFUS‐enhanced drug uptake in prostate tumors was significant. This increased uptake may be due to increased extravasation by pFUS. Optimal pFUS parameters may exist to maximize the drug uptake, and this study using Dox demonstrated a quantitative method for such systematic parametric studies. In addition, this study may provide useful data for the potential application of pFUS‐mediated Dox delivery for prostate tumor therapy.
Looking Beyond Historical Patient Outcomes to Improve Clinical Models
Authors: Chia Chih-Chun , Rubinfeld Ilan , Scirica Benjamin M. , McMillan Sean , Gurm Hitinder S. , Syed Zeeshan
Published: April 2012

Clinical models can be improved by decreasing the importance assigned to fitting historical patient outcomes in often small and imperfectly characterized derivation cohorts.
Tweaking the Social Network
Authors: Gomez-Mancilla Baltazar
Published: April 2012

A preclinical mouse model of autism spectrum disorder paves the way for clinical trials with a glutamate receptor antagonist.
Response to Comment on “A Peptidomimetic Targeting White Fat Causes Weight Loss and Improved Insulin Resistance in Obese Monkeys”
Authors: Barnhart Kirstin F. , Christianson Dawn R. , Kolonin Mikhail G. , Hulvat James F. , Chan Lawrence , Arap Wadih , Pasqualini Renata
Published: April 2012

Several lines of evidence indicate that the effects of adipotide on weight loss and food consumption in obese monkeys are not due to a toxic effect, but rather result from the targeting mechanism of adipotide.
Tree macrofossils of Younger Dryas age from Cohoes, New York State, USA
Authors: Miller Norton G. , Griggs Carol B.
Published: April 2012

Tree macrofossils dating from the middle to end (about 1000 years, ca. 12 600–11 600 cal years BP) of the Younger Dryas chronozone were found in an organic deposit on the southwest side of the Mohawk River, near its junction with the Hudson River in Cohoes, New York, USA. The fossils included substantial wood fragments, associated plant remains, and pollen, which indicate a forest of white spruce ( Picea glauca ), balsam fir ( Abies balsamea ), and tamarack ( Larix laricina ). The presence of white, rather than black ( P. mariana ) or red ( P. rubens ) spruce in the Younger Dryas was probably due to a riparian-type environment, confirmed by its location and American beaver tooth marks on some of the wood fragments. The clusters of wood radiocarbon dates indicate periodic changes in erosion and deposition at the site. One possible but very short decline (temperature reversal?) may be indicated by tree-ring growth, but in general, the ring widths of the trees and their growth responses suggest variable but slowly improving conditions over time, possibly from warming temperatures, before the end of the Younger Dryas.
Deep transverse basement structural control of mineral systems in the southeastern Canadian Cordillera1Geological Survey of Canada Contribution 20110294.
Authors: McMechan M.E.
Published: April 2012

Intermittent reactivation of deep Paleoproterozoic- and Archean-aged transverse structures in the North American cratonic basement beneath the southeastern Canadian Cordillera exerted an important influence on the subsequent sedimentary, intrusive, deformation, and mineralization history. Two regional crossbelt transverse structural corridors recognized by recurrent episodic changes in sediment thickness and facies, and anomalous transverse structural trends, occur within the thrust and fold belt. Palinspastic restoration of the exposed transported structural corridors showed that the northern and southern structural corridors are cover expressions of the Red Deer zone and Vulcan Low structures in the cratonic basement, respectively. Transverse basement-controlled structural corridors enhanced the mineral potential and mineralization systems along them by localization of sedimentary facies favourable for mineralization, hydrothermal flow, intrusions, and favourable structures for mineralization. Greatest enhancement of hydrothermal flow and mineralization occurred near the intersection of basin-parallel and transverse structures. Greater opportunity for mineralization and intrusion occurred not only along the exposed corridors, but also in the west, above their undeformed “root” in the basement. The processes that intensified mineralization and localized intrusions along transverse basement-controlled structural corridors in the southeastern Canadian Cordillera should have occurred in thrust and fold belts elsewhere. The niobium-bearing Aley carbonatite complex in the eastern Cordillera of northeastern British Columbia may be an example of this.
TRANSITION FREQUENCY OF STRONG-COUPLING IMPURITY BOUND POLARON IN AN ASYMMETRIC QUANTUM DOT
Authors: WANG CHENG-SHUN , CHEN YU-FANG , XIAO JING-JIN
Published: April 2012

Properties of the excited state of strong-coupling impurity bound polaron in an asymmetric quantum dot are studied by using linear combination operator and unitary transformation methods. The first internal excited state energy, the excitation energy and the transition frequency between the first internal excited and the ground states of the impurity bound polaron as functions of the transverse and the longitudinal effective confinement lengths of the dot, the electron–phonon coupling strength and the Coulomb bound potential were derived. Our numerical results show that they will increase with decreasing the effective confinement lengths, due to interesting quantum size confining effects. But they are an increasing functions of the Coulomb bound potential. The first internal excited state energy is a decreasing function of the electron–phonon coupling strength whereas the transition frequency and the excitation energy are an increasing one of the electron–phonon coupling strength.
CLASSIFYING INNOVATION
Authors: MILLER LAWRENCE , MILLER RUTH
Published: April 2012

This technical note describes initial efforts of the University of Toledo Accelerated Radical Innovation (ARI) research team in beginning to develop a comprehensive classification system, describing all dimensions, types, and activity levels of innovation. It does not purport to provide a finalized system, but rather is meant to spark discussion, and motivate additional development and research efforts leading toward a complete comprehensive and understandable system for classifying innovation.
ENABLING DISPERSED INNOVATION — HOW THE UNITED STATES CAN UTILIZE ITS LONG TAIL OF TALENT
Authors: RAMACHANDRAN RAJA
Published: April 2012

The United States, having enjoyed nearly half a century of technology leadership, today faces a number of challenges in maintaining its innovation advantage. These include: (1) Declining science and engineering talent pipeline, (2) increased global competition, (3) rigidity of the venture capital model, and (4) saturation of key technology centers. In a period where all Science Engineering (S&E) talent is not necessarily deployed to S&E occupations due to other opportunities or geographical challenges, "Dispersed Innovation," the idea of a location independent model to achieve higher technical utilization of American S&E talent is a proposed solution which consists of four key components: (1) Build out of advanced transportation networks, (2) increased use of collaboration tools, (3) cultural acceptance of entrepreneurship, and (4) increased funding options and models.
DYNAMIC STABILITY OF A BEAM ON AN ELASTIC FOUNDATION INCLUDING STRESS WAVE EFFECTS
Authors: LIU YING , LU G.
Published: April 2012

This paper examines the dynamic stability of an elastic beam on the elastic foundation, in which the stress wave effect is taken into account. Based on Euler–Bernoulli beam theory, the dynamic response of the elastic beam on the elastic foundation to a small transverse perturbation is analyzed. By considering the stress wave propagation in the beam and the constraint of the elastic foundation, the critical bifurcation condition of elastic beam is derived, and the critical axial load of the elastic beam is predicted. Furthermore, the effects of the elastic foundation and the beam length on buckling condition are discussed by using numeric examples. Finally, an approximate solution of critical axial load for elastic beam on the elastic foundation is provided, which may be used to investigate elastic beam buckling problem.
POSTBUCKLING OF PIEZOELECTRIC NANOBEAMS WITH SURFACE EFFECTS
Authors: LI YUHANG , CHEN CHI , FANG BO , ZHANG JIAZHONG , SONG JIZHOU
Published: April 2012

Surface effects, including surface elasticity, surface piezoelectricity and residual surface stress, on the postbuckling of piezoelectric nanobeams due to an electric field are investigated using an energy method in this paper. The critical buckling voltage and amplitude are obtained analytically in terms of the bulk and surface material properties and geometric parameters. The results show that surface effects play a significant role in the postbuckling of piezoelectric nanobeams. It is found that the influences of surface piezoelectricity and residual surface stress are more prominent than the surface elasticity. These results might be helpful for designing piezoelectric nanobeam-based devices.
A CLASSIFICATION INDICES-BASED MODEL FOR NET PRIMARY PRODUCTIVITY (NPP) AND POTENTIAL PRODUCTIVITY OF VEGETATION IN CHINA
Authors: LIN HUILONG , ZHAO JUN , LIANG TIANGANG , BOGAERT JAN , LI ZHENQING
Published: April 2012

Net Primary Productivity (NPP) is an important parameter, which is closely connected with global climate change, the global carbon balance and cycle. The study of climate-vegetation interaction is the basis for research on the responses of terrestrial ecosystem to global change and mainly comprises two important components: climate vegetation classification and the NPP of the natural vegetation. Comparing NPP estimated from the classification indices-based model with NPP derived from measurements at 3767 sites in China indicated that the classification indices-based model was capable of estimating large scale NPP. Annual cumulative temperature above 0°C and a moisture index, two main factors affecting NPP, were spatially plotted with the ArcGIS grid tool based on measured data in 2348 meteorological stations from 1961 to 2006. The distribution of NPP for potential vegetation classes under present climate conditions was simulated by the classification indices-based model. The model estimated the total NPP of potential terrestrial vegetation of China to fluctuate between 1.93 and 4.54 Pg C year-1. It provides a reliable means for scaling-up from site to regional scales, and the findings could potentially favor China's position in reducing global warming gases as outlined in the Kyoto Protocol in order to fulfill China's commitment of reducing greenhouse gases.
CVTree: A WHOLE-GENOME-BASED AND ALIGNMENT-FREE APPROACH TO MICROBIAL PHYLOGENY
Authors: HAO BAILIN
Published: April 2012

The number of sequenced genomes of Archaea, Bacteria, and Fungi accumulates rapidly. Several thousands genomes of these unicellular organisms will be available in a few years. Due to the extremely large difference in genome size and gene content it is difficult to use the traditional alignment-based method to infer phylogeny from the genomes. An alignment-free and whole-genome-based approach called CVTree has been developed and successfully applied to these organisms. As CVTree has been successfully applied to genomes of viruses, chloroplasts, Bacteria, Archaea and fungi, in this brief review we will mainly touch on some mathematical problems related to the foundation of the new approach, including a few yet unsolved problems, such as the violation of the triangular inequalities of the dissimilarity measure used in the CVTree method.
A MATHEMATICAL APPROACH TO STRUCTURAL TRANSITIONS IN VIRAL CAPSIDS
Authors: INDELICATO GIULIANA , TWAROCK REIDUN
Published: April 2012

The majority of viruses have protein containers, called capsids, in which proteins are arranged with icosahedral symmetry. The capsids of these viruses follow structural blueprints that can be modelled as subsets of 3-dimensional aperiodic lattices called quasicrystals. These, in turn, can be obained by projection from 6-dimensional Bravais lattices. In this work we apply the crystallographic theory of phase transitions to these 6D lattices, and via projection of these results derive information on the structural transitions of viruses important for infection.
ONE APPROACH TO COMPUTER MODELING OF MICROKINETICS FOR BIOTECHNOLOGICAL PROCESSES
Authors: KABILJANOV A. S. , FOZILOVA M. M. , KUCHKAROV F. S.
Published: April 2012

Intelligence — algorithmic method of modeling of microkinetics for biotechnological processes (BTP) is considered. The generalized mathematical model of microkinetics of biotechnological processes received on the basis of the system approach is given. The question of regularization of a task of parametrical identification is considered.
A MORPHOMETRIC ANALYSIS OF HYLARANA SIGNATA GROUP (PREVIOUSLY KNOWN AS RANA SIGNATA AND RANA PICTURATA) OF MALAYSIA
Authors: ZAINUDIN RAMLAH , SAZALI SITI NURLYDIA
Published: April 2012

A study on morphometrical variations of Malaysian Hylarana signata group was conducted to reveal the morphological relationships within the species group. Twenty-seven morphological characters from 18 individuals of H. signata and H. picturata were measured and recorded. The numerical data were analysed using Discriminant Function Analysis in SPSS program version 16.0 and UPGMA Cluster Analysis in Minitab program version 14.0. The results show the complexity clustering between the examined species that might be due to ancient polymorphism of the lineages or cryptic species within the group. Hence, further study should include more representatives in order to fully elucidate the morphological relationships of H. signata group.
MATHEMATICAL MODEL OF THREE SPECIES FOOD CHAIN INTERACTION WITH MIXED FUNCTIONAL RESPONSE
Authors: WS MADA SANJAYA , MOHD ISMAIL BIN , MAMAT MUSTAFA , SALLEH ZABIDIN
Published: April 2012

In this paper, we study mathematical model of ecology with a tritrophic food chain composed of a classical Lotka-Volterra functional response for prey and predator, and a Holling type-III functional response for predator and super predator. There are two equilibrium points of the system. In the parameter space, there are passages from instability to stability, which are called Hopf bifurcation points. For the first equilibrium point, it is possible to find bifurcation points analytically and to prove that the system has periodic solutions around these points. Furthermore the dynamical behaviors of this model are investigated. Models for biologically reasonable parameter values, exhibits stable, unstable periodic and limit cycles. The dynamical behavior is found to be very sensitive to parameter values as well as the parameters of the practical life. Computer simulations are carried out to explain the analytical findings.
MODELING OF BIOLOGICAL POPULATIONS USING FUZZY DIFFERENTIAL EQUATIONS
Authors: AHMAD M. Z. , HASAN M. K.
Published: April 2012

This paper explores the application of fuzzy differential equations in modeling of prey and predator populations. A new model, referred to as fuzzy predator-prey model is introduced. This model is then solved numerically by means of a fuzzy Euler method. Some numerical results are presented in order to show the evolution of the prey and predator populations over time. Finally, the stability of the new fuzzy model is studied and shown graphically in the fuzzy phase plane.
STAGE-STRUCTURED POPULATION DYNAMICS OF AEDES AEGYPTI
Authors: YUSOFF NURAINI , BUDIN HARUN , ISMAIL SALEMAH
Published: April 2012

Aedes aegypti is the main vector in the transmission of dengue fever, a vector-borne disease affecting world population living in tropical and sub-tropical countries. Better understanding of the dynamics of its population growth will help in the efforts of controlling the spread of this disease. In looking at the population dynamics of Aedes aegypti, this paper explored the stage-structured modeling of the population growth of the mosquito using the matrix population model. The life cycle of the mosquito was divided into five stages: eggs, larvae, pupae, adult1 and adult2. Developmental rates were obtained for the average Malaysian temperature and these were used in constructing the transition matrix for the matrix model. The model, which was based only on temperature, projected that the population of Aedes aegypti will blow up with time, which is not realistic. For further work, other factors need to be taken into account to obtain a more realistic result.
NUMERICAL SOLUTION OF 1D AND 2D THERMOELASTIC COUPLED PROBLEMS
Authors: KHALDJIGITOV ABDUVALI , QALANDAROV AZIZ , NIK LONG NIK MOHD ASRI , ESHQUVATOV ZAINIDIN
Published: April 2012

Study the heats propagation in a solid, liquid continuums is an actual problems. The liquid continuum may be considered as a biomaterial. The present investigation is devoted to the study of 1D and 2D dynamic coupled thermo elasticity problems. In case of coupled problems the motion and heat conduction equations are considered together. For numerical solution of thermo elasticity problems an explicit and implicit schemes are constructed. The explicit and implicit schemes by using recurrent formulas and the "consecutive" methods are solved. Comparison of two results shows a good coincidence.
EVASION FROM ONE PURSUER IN A HILBERT SPACE
Authors: ALLAHABI FATEH , IBRAGIMOV G.I.
Published: April 2012

We study a differential game of one pursuer and one evader described by infinite systems of second order ordinary differential equations. Controls of players are subjected to geometric constraints. Differential game is considered in Hilbert spaces. We proved one theorem on evasion. Moreover, we constructed explicitly a control of the evader.
SIMULATION OF KORTEWEG DE VRIES EQUATION
Authors: MAT ZIN S. , ARIFFIN W. N. M. , HASHIM ALI S. A.
Published: April 2012

Korteweg de Vries (KdV) equation has been used as a mathematical model of shallow water waves. In this paper, we present one-, two-, and three-soliton solution of KdV equation. By definition, soliton is a nonlinear wave that maintains its properties (shape and velocity) upon interaction with each other. In order to investigate the behavior of soliton solutions of KdV equation and the interaction process of the two- and three-solitons, computer programs have been successfully simulated. Results from these simulations confirm that the solutions of KdV equation obtained are the soliton solutions.
Receptor-mediated nonproteolytic activation of prorenin and induction of TGF-β1 and PAI-1 expression in renal mesangial cells
Authors: Zhang Jiandong , Wu Jie , Gu Chunyan , Noble Nancy A. , Border Wayne A. , Huang Yufeng
Published: April 2012

While elevated plasma prorenin levels are commonly found in diabetic patients and correlate with diabetic nephropathy, the pathological role of prorenin, if any, remains unclear. Prorenin binding to the (pro)renin receptor [(p)RR] unmasks prorenin catalytic activity. We asked whether elevated prorenin could be activated at the site of renal mesangial cells (MCs) through receptor binding without being proteolytically converted to renin. Recombinant inactive rat prorenin and a mutant prorenin that is noncleavable, i.e., cannot be activated proteolytically, are produced in 293 cells. After MCs were incubated with 10−7 M native or mutant prorenin for 6 h, cultured supernatant acquired the ability to generate angiotensin I (ANG I) from angiotensinogen, indicating both prorenins were activated. Small interfering RNA (siRNA) against the (p)RR blocked their activation. Furthermore, either native or mutant rat prorenin at 10−7 M alone similarly and significantly induced transforming growth factor-β1, plasminogen activator inhibitor-1 (PAI-1), and fibronectin mRNA expression, and these effects were blocked by (p)RR siRNA, but not by the ANG II receptor antagonist, saralasin. When angiotensinogen was also added to cultured MCs with inactive native or mutant prorenin, PAI-1 and fibronectin were further increased significantly compared with prorenin or mutant prorenin alone. This effect was blocked partially by treatment with (p)RR siRNA or saralasin. We conclude that prorenin binds the (p)RR on renal MCs and is activated nonproteolytically. This activation leads to increased expression of PAI-1 and transforming growth factor-β1 via ANG II-independent and ANG II-dependent mechanisms. These data provide a mechanism by which elevated prorenin levels in diabetes may play a role in the development of diabetic nephropathy.
Physiological Implications of Hydrogen Sulfide: A Whiff Exploration That Blossomed
Authors: Wang Rui
Published: April 2012

The important life-supporting role of hydrogen sulfide (H2S) has evolved from bacteria to plants, invertebrates, vertebrates, and finally to mammals. Over the centuries, however, H2S had only been known for its toxicity and environmental hazard. Physiological importance of H2S has been appreciated for about a decade. It started by the discovery of endogenous H2S production in mammalian cells and gained momentum by typifying this gasotransmitter with a variety of physiological functions. The H2S-catalyzing enzymes are differentially expressed in cardiovascular, neuronal, immune, renal, respiratory, gastrointestinal, reproductive, liver, and endocrine systems and affect the functions of these systems through the production of H2S. The physiological functions of H2S are mediated by different molecular targets, such as different ion channels and signaling proteins. Alternations of H2S metabolism lead to an array of pathological disturbances in the form of hypertension, atherosclerosis, heart failure, diabetes, cirrhosis, inflammation, sepsis, neurodegenerative disease, erectile dysfunction, and asthma, to name a few. Many new technologies have been developed to detect endogenous H2S production, and novel H2S-delivery compounds have been invented to aid therapeutic intervention of diseases related to abnormal H2S metabolism. While acknowledging the challenges ahead, research on H2S physiology and medicine is entering an exponential exploration era.
The Germline Stem Cell Niche Unit in Mammalian Testes
Authors: Oatley Jon M. , Brinster Ralph L.
Published: April 2012

This review addresses current understanding of the germline stem cell niche unit in mammalian testes. Spermatogenesis is a classic model of tissue-specific stem cell function relying on self-renewal and differentiation of spermatogonial stem cells (SSCs). These fate decisions are influenced by a niche microenvironment composed of a growth factor milieu that is provided by several testis somatic support cell populations. Investigations over the last two decades have identified key determinants of the SSC niche including cytokines that regulate SSC functions and support cells providing these factors, adhesion molecules that influence SSC homing, and developmental heterogeneity of the niche during postnatal aging. Emerging evidence suggests that Sertoli cells are a key support cell population influencing the formation and function of niches by secreting soluble factors and possibly orchestrating contributions of other support cells. Investigations with mice have shown that niche influence on SSC proliferation differs during early postnatal development and adulthood. Moreover, there is mounting evidence of an age-related decline in niche function, which is likely influenced by systemic factors. Defining the attributes of stem cell niches is key to developing methods to utilize these cells for regenerative medicine. The SSC population and associated niche comprise a valuable model system for study that provides fundamental knowledge about the biology of tissue-specific stem cells and their capacity to sustain homeostasis of regenerating tissue lineages. While the stem cell is essential for maintenance of all self-renewing tissues and has received considerable attention, the role of niche cells is at least as important and may prove to be more receptive to modification in regenerative medicine.
Mammalian MAPK Signal Transduction Pathways Activated by Stress and Inflammation: A 10-Year Update
Authors: Kyriakis John M. , Avruch Joseph
Published: April 2012

The mammalian stress-activated families of mitogen-activated protein kinases (MAPKs) were first elucidated in 1994, and by 2001, substantial progress had been made in identifying the architecture of the pathways upstream of these kinases as well as in cataloguing candidate substrates. This information remains largely sound. Nevertheless, an informed understanding of the physiological and pathophysiological roles of these kinases remained to be accomplished. In the past decade, there has been an explosion of new work using RNAi in cells, as well as transgenic, knockout and conditional knockout technology in mice that has provided valuable insight into the functions of stress-activated MAPK pathways. These findings have important implications in our understanding of organ development, innate and acquired immunity, and diseases such as atherosclerosis, tumorigenesis, and type 2 diabetes. These new developments bring us within striking distance of the development and validation of novel treatment strategies. Herein we first summarize the molecular components of the mammalian stress-regulated MAPK pathways and their regulation as described thus far. We then review some of the in vivo functions of these pathways.