bluuebunny/crossref_metadata_2025 huggingface dataset:
STOCHASTIC RESONANCE IN A SIMPLE MODEL OF MAGNETIC REVERSALS
Authors: BENZI ROBERTO , PINTON JEAN-FRANÇOIS
Published: February 2012

We discuss the effect of stochastic resonance on a simple model of magnetic reversals. The model exhibits statistically stationary solutions and bimodal distribution of the large scale magnetic field. We observe a nontrivial amplification of stochastic resonance induced by turbulent fluctuations, i.e. the amplitude of the external periodic perturbation needed for stochastic resonance to occur is much smaller than the one estimated by the equilibrium probability distribution of the unperturbed system. We argue that similar amplifications can be observed in many physical systems where turbulent fluctuations are needed to maintain large scale equilibria.
THE ENERGY AND CENTRALITY DEPENDENCES OF THE PSEUDORAPIDITY DISTRIBUTIONS OF THE CHARGED PARTICLES INAu+AuCOLLISIONS
Authors: JIANG ZHIJIN , SUN YUFEN , LI QINGGUANG
Published: February 2012

We present the pseudorapidity distributions of the charged particles in nucleus–nucleus collisions as the function of beam energy and impact parameter through weighted superposition of the pseudorapidity distributions in the effective binary nucleon–nucleon collisions. We then analyze with the theoretical model the experimental measurements carried out by BNL-RHIC-PHOBOS Collaboration in Au + Au collisions at [Formula: see text], 130, 62.4 and 19.6 GeV. The model has only two free parameters and the theoretical results favor the experimental measurements well.
NUCLEAR STRUCTURE STUDY AROUND Z = 28
Authors: SRIVASTAVA P. C. , MEHROTRA I.
Published: February 2012

Yrast levels of Ni , Cu and Zn isotopes for 40 ≤ N ≤ 50 have been described by state-of-the-art shell model calculations with three recently available interactions using 56 Ni as a core in the f5/2pg9/2 model space. The results are unsatisfactory viz. large E(2+) for very neutron-rich nuclei, small B(E2) values in comparison to experimental values. These results indicate an importance of inclusion of πf7/2 and νd5/2 orbitals in the model space to reproduce collectivity in this region.
SIZE-DEPENDENT MASS DENSITY OF NANOCRYSTALS
Authors: SAFAEI ALI
Published: February 2012

A new simple, lattice-type-sensitive model has been developed for the size-dependency of the mass density of individual elemental and compound nanocrystals. It has also been generalized for a multi-composition nanocrystal, and can be used for metallic oxides, ionic crystals and alloys. The model has been corroborated with the experimental data for the particle size-dependent apparent density (AD) of silica nanopowder.
Increased Na+/H+ exchanger activity on the apical surface of a cilium-deficient cortical collecting duct principal cell model of polycystic kidney disease
Authors: Olteanu Dragos , Liu Xiaofen , Liu Wen , Roper Venus C. , Sharma Neeraj , Yoder Bradley K. , Satlin Lisa M. , Schwiebert Erik M. , Bevensee Mark O.
Published: February 2012

Pathophysiological anomalies in autosomal dominant and recessive forms of polycystic kidney disease (PKD) may derive from impaired function/formation of the apical central monocilium of ductal epithelia such as that seen in the Oak Ridge polycystic kidney or orpk ( Ift88 Tg737Rpw) mouse and its immortalized cell models for the renal collecting duct. According to a previous study, Na/H exchanger (NHE) activity may contribute to hyperabsorptive Na+ movement in cilium-deficient (“mutant”) cortical collecting duct principal cell monolayers derived from the orpk mice compared with cilium-competent (“rescued”) monolayers. To examine NHE activity, we measured intracellular pH (pHi) by fluorescence imaging with the pH-sensitive dye BCECF, and used a custom-designed perfusion chamber to control the apical and basolateral solutions independently. Both mutant and rescued monolayers exhibited basolateral Na+-dependent acid-base transporter activity in the nominal absence of CO2/HCO3−. However, only the mutant cells displayed appreciable apical Na+-induced pHi recoveries from NH4+ prepulse-induced acid loads. Similar results were obtained with isolated, perfused collecting ducts from orpk vs. wild-type mice. The pHi dependence of basolateral cariporide/HOE-694-sensitive NHE activity under our experimental conditions was similar in both mutant and rescued cells, and 3.5- to 4.5-fold greater than apical HOE-sensitive NHE activity in the mutant cells (pHi 6.23–6.68). Increased apical NHE activity correlated with increased apical NHE1 expression in the mutant cells, and increased apical localization in collecting ducts of kidney sections from orpk vs. control mice. A kidney-specific conditional cilium-knockout mouse produced a more acidic urine compared with wild-type littermates and became alkalotic by 28 days of age. This study provides the first description of altered NHE activity, and an associated acid-base anomaly in any form of PKD.
Ursodeoxycholate modulates bile flow and bile salt pool independently from the cystic fibrosis transmembrane regulator (Cftr) in mice
Authors: Bodewes Frank A. J. A. , Wouthuyzen-Bakker Marjan , Bijvelds Marcel J. , Havinga Rick , de Jonge Hugo R. , Verkade Henkjan J.
Published: February 2012

Cystic fibrosis liver disease (CFLD) is treated with ursodeoxycholate (UDCA). Our aim was to evaluate, in cystic fibrosis transmembrane regulator knockout ( Cftr−/−) mice and wild-type controls, whether the supposed therapeutic action of UDCA is mediated via choleretic activity or effects on bile salt metabolism. Cftr−/−mice and controls, under general anesthesia, were intravenously infused with tauroursodeoxycholate (TUDCA) in increasing dosage or were fed either standard or UDCA-enriched chow (0.5% wt/wt) for 3 wk. Bile flow and bile composition were characterized. In chow-fed mice, we analyzed bile salt synthesis and pool size of cholate (CA). In both Cftr−/−and controls intravenous TUDCA stimulated bile flow by ∼250% and dietary UDCA by ∼500%, compared with untreated animals ( P < 0.05). In non-UDCA-treated Cftr−/−mice, the proportion of CA in bile was higher compared with that in controls (61 ± 4 vs. 46 ± 4%; P < 0.05), accompanied by an increased CA synthesis [16 ± 1 vs. 10 ± 2 μmol·h−1·100 g body wt (BW)−1; P < 0.05] and CA pool size (28 ± 3 vs. 19 ± 1 μmol/100 g BW; P < 0.05). In both Cftr−/−and controls, UDCA treatment drastically reduced the proportion of CA in bile below 5% and diminished CA synthesis (2.3 ± 0.3 vs. 2.2 ± 0.4 μmol·day−1·100 g BW−1; nonsignificant) and CA pool size (3.6 ± 0.6 vs. 1.5 ± 0.3 μmol/100 g BW; P < 0.05). Acute TUDCA infusion and chronic UDCA treatment both stimulate bile flow in cystic fibrosis conditions independently from Cftr function. Chronic UDCA treatment reduces the hydrophobicity of the bile salt pool in Cftr−/−mice. These results support a potential beneficial effect of UDCA on bile flow and bile salt metabolism in cystic fibrosis conditions.
Angiotensin II regulates growth of the developing papillas ex vivo
Authors: Song Renfang , Preston Graeme , Khalili Ali , El-Dahr Samir S. , Yosypiv Ihor V.
Published: February 2012

We tested the hypothesis that lack of angiotensin (ANG) II production in angiotensinogen ( AGT)-deficient mice or pharmacologic antagonism of ANG II AT1receptor (AT1R) impairs growth of the developing papillas ex vivo, thus contributing to the hypoplastic renal medulla phenotype observed in AGT- or AT1R-null mice. Papillas were dissected from Hoxb7GFP+or AGT+/+,+/−,−/−mouse metanephroi on postnatal day P3 and grown in three-dimentional collagen matrix gels in the presence of media (control), ANG II (10−5M), or the specific AT1R antagonist candesartan (10−6M) for 24 h. Percent reduction in papillary length was attenuated in AGT+/+and in AGT+/−compared with AGT−/−(−18.4 ± 1.3 vs. −32.2 ± 1.6%, P < 0.05, −22.8 ± 1.3 vs. −32.2 ± 1.6%, P < 0.05, respectively). ANG II blunted the decrease in papilla length observed in respective media-treated controls in Hoxb7GFP+(−1.5 ± 0.3 vs. −10.0 ± 1.4%, P < 0.05) or AGT+/+,+/−, and−/−papillas (−12.8 ± 0.7 vs. −18.4 ± 1.3%, P < 0.05, −16.8 ± 1.1 vs. −23 ± 1.2%, P < 0.05; −26.2 ± 1.6 vs. −32.2 ± 1.6%, P < 0.05, respectively). In contrast, percent decrease in the length of Hoxb7GFP+papillas in the presence of the AT1R antagonist candesartan was higher compared with control (−24.3 ± 2.1 vs. −10.5 ± 1.8%, P < 0.05). The number of proliferating phospho-histone H3 (pH3)-positive collecting duct cells was lower, whereas the number of caspase 3-positive cells undergoing apoptosis was higher in candesartan- vs. media-treated papillas (pH3: 12 ± 1.4 vs. 21 ± 2.1, P < 0.01; caspase 3: 3.8 ± 0.5 vs. 1.7 ± 0.2, P < 0.01). Using quantitative RT-PCR, we demonstrate that AT1R signaling regulates the expression of genes implicated in morphogenesis of the renal medulla. We conclude that AT1R prevents shrinkage of the developing papillas observed ex vivo via control of Wnt7b, FGF7, β-catenin, calcineurin B1, and α3 integrin gene expression, collecting duct cell proliferation, and survival.
Increased urinary excretion of nephrin, podocalyxin, and βig-h3 in women with preeclampsia
Authors: Wang Yuping , Zhao Shuang , Loyd Susan , Groome Lynn J.
Published: February 2012

Emerging evidence has shown that podocyte injury and reduced specific podocyte protein expressions contribute to proteinuria in preeclampsia. We collected urine specimens from women with preeclampsia to study whether podocyte-specific protein shedding is associated with renal barrier dysfunction. Urine specimens from women with normal pregnancies and from pregnant women complicated by chronic hypertension were used for comparison. We determined soluble podocyte slit protein nephrin levels in the urine specimens. Podocalyxin, βig-h3, and VEGF concentrations were also measured. We found that nephrin and podocalyxin were barely detectable in the urine specimens from normal pregnant women and from women with chronic hypertension. In preeclampsia, urinary nephrin and podocalyxin concentrations were significantly increased and highly correlated to each other, r2= 0.595. Nephrin and podocalyxin were also correlated with urine protein concentrations. βig-h3 was detected in the urine specimens from women with preeclampsia, and it is highly correlated with nephrin and podocalyxin concentrations in preeclampsia. βig-h3 was undetectable in normal pregnancy and pregnancy complicated by chronic hypertension. Elevated VEGF levels were also found in women with preeclampsia compared with those of normal pregnancy and pregnancy complicated by chronic hypertension. These results provide strong evidence that podocyte protein shedding occurs in preeclampsia, and their levels are associated with proteinuria. The finding of urinary βig-h3 excretion in preeclampsia suggests that increased transforming growth factor activity might also be involved in the kidney lesion in this pregnancy disorder.
Role of cyclooxygenase-1-mediated prostacyclin synthesis in endothelium-dependent vasoconstrictor activity of porcine interlobular renal arteries
Authors: Liu Bin , Luo Wenhong , Zhang Yingzhan , Li Hui , Zhu Ningxia , Huang Dongyang , Zhou Yingbi
Published: February 2012

This study aimed to determine whether PGI2 would be evoked by the endogenous endothelial B2 receptor agonist bradykinin (BK) in the porcine interlobular renal artery and, if so, to determine how it would influence the vasomotor reaction, and the specific cyclooxygenase (COX) isoform(s) involved in its synthesis. The production of the PGI2 metabolite 6-keto-PGF1α was analyzed with HPLC-mass spectroscopy, while vasomotor reaction to PGI2 or BK was determined with isometric force measurement. Results showed that BK evoked an increase in the production of 6-keto-PGF1α, which was abolished by endothelial denudation that removed COX-1 expression, or was reduced by COX-1 inhibition. Interestingly, PGI2 evoked a potent contraction, which was prevented by antagonizing thromboxane-prostanoid (TP) receptors and was not enhanced by antagonizing the vasodilator PGI2 (IP) receptors. The IP receptor agonists MRE-269 and iloprost did not induce any relaxation. Moreover, iloprost, which is also a PGI2 analog, caused a contraction, which was sensitive to TP receptor antagonism, but was to a significantly lesser extent than that of PGI2. Indeed, IP receptors were not detected by RT-PCR or Western blotting in the vessel. Following nitric oxide synthase (NOS) inhibition, BK also evoked an endothelium-dependent contraction, which was blocked by TP receptor antagonism. In addition, inhibition of COX-1 (but not COX-2) impeded the vasoconstrictor activity of BK and expedited the relaxation induced by the agonist in NOS-intact vessels. These results demonstrate that in the porcine interlobular renal artery BK evokes endothelial COX-1-mediated PGI2 synthesis, which mainly leads to the activation of TP receptors and a vasoconstrictor response, possibly due to a scarcity of vasodilator activity mediated by IP receptors. Also, our data suggested that the effect of a PGI2 analog on TP receptors could be reduced compared with that of PGI2 due to modified structure as with iloprost.
Protein kinase C-α mediates hypertonicity-stimulated increase in urea transporter phosphorylation in the inner medullary collecting duct
Authors: Klein Janet D. , Martin Christopher F. , Kent Kimilia J. , Sands Jeff M.
Published: February 2012

The UT-A1 urea transporter plays a critical role in the production of concentrated urine. Both vasopressin and hypertonicity increase urea permeability in rat terminal inner medullary collecting ducts (IMCD). Each agonist independently increases UT-A1 phosphorylation and apical plasma membrane accumulation. Vasopressin activates PKA and phosphorylates UT-A1 at serines 486 and 499. Hypertonicity stimulates urea permeability through protein kinase C (PKC) and intracellular calcium. To determine whether the hypertonic stimulation of urea permeability results from a PKC-mediated phosphorylation of UT-A1, rat IMCDs were metabolically labeled with [32P]. Hypertonicity stimulated UT-A1 phosphorylation, and this increase was blocked by preincubation with a PKC inhibitor. IMCDs were biotinylated to assess plasma membrane UT-A1. Hypertonicity increased biotinylated UT-A1, and this increase was blocked by preincubation with a PKC inhibitor. When PKC was directly activated using a phorbol ester, total UT-A1 phosphorylation increased, but phosphorylation at serine 486 was not increased, indicating that PKC did not phosphorylate UT-A1 at the same residue as PKA. Since PKC-α is a calcium-dependent PKC isoform and PKC-α knockout mice have a urine-concentrating defect, it suggested that PKC-α may mediate the response to hypertonicity. Consistent with this hypothesis, hypertonicity increased phospho-PKC-α in rat IMCDs. Finally, PKC-α knockout mice were used to determine whether hypertonicity could stimulate UT-A1 phosphorylation in the absence of PKC-α. Hypertonicity significantly increased UT-A1 phosphorylation in wild-type mice but not in PKC-α knockout mice. We conclude that PKC-α mediates the hypertonicity-stimulated increase in UT-A1 phosphorylation in the IMCD.
Contraction level-related modulation of corticomuscular coherence differs between the tibialis anterior and soleus muscles in humans
Authors: Ushiyama Junichi , Masakado Yoshihisa , Fujiwara Toshiyuki , Tsuji Tetsuya , Hase Kimitaka , Kimura Akio , Liu Meigen , Ushiba Junichi
Published: February 2012

The sensorimotor cortex activity measured by scalp EEG shows coherence with electromyogram (EMG) activity within the 15- to 35-Hz frequency band (β-band) during weak to moderate intensity of isometric voluntary contraction. This coupling is known to change its frequency band to the 35- to 60-Hz band (γ-band) during strong contraction. This study aimed to examine whether such contraction level-related modulation of corticomuscular coupling differs between muscles with different muscle compositions and functions. In 11 healthy young adults, we quantified the coherence between EEG over the sensorimotor cortex and rectified EMG during tonic isometric voluntary contraction at 10–70% of maximal voluntary contraction of the tibialis anterior (TA) and soleus (SOL) muscles, respectively. In the TA, the EEG-EMG coherence shifted from the β-band to the γ-band with increasing contraction level. Indeed, the magnitude of β-band EEG-EMG coherence was significantly decreased, whereas that of γ-band coherence was significantly increased, when the contraction level was above 60% of maximal voluntary contraction. In contrast to the TA, the SOL showed no such frequency changes of EEG-EMG coherence with alterations in the contraction levels. In other words, the maximal peak of EEG-EMG coherence in the SOL existed within the β-band, irrespective of the contraction levels. These findings suggest that the central nervous system regulates the frequency of corticomuscular coupling to exert the desired levels of muscle force and, notably, that the applicable rhythmicity of the coupling for performing strong contractions differs between muscles, depending on the physiological muscle compositions and functions of the contracting muscle.
The contribution of vision, proprioception, and efference copy in storing a neural representation for guiding trail leg trajectory over an obstacle
Authors: Lajoie Kim , Bloomfield Leigh W. , Nelson Fraser J. , Suh Jaewon J. , Marigold Daniel S.
Published: February 2012

Stepping over obstacles requires vision to guide the leading leg, but direct visual information is not available to guide the trailing leg. The neural mechanisms for establishing a stored obstacle representation and thus facilitating the trail leg trajectory in humans are unknown. Twenty-four subjects participated in one of three experiments, which were designed to investigate the contribution of visual, proprioceptive, and efference copy signals. Subjects stepped over an obstacle with their lead leg, stopped, and straddled the obstacle for a delay period before stepping over it with their trail leg while toe elevation was recorded. Subsequently, we calculated maximum toe elevation and toe clearance. First, we found that subjects could accurately scale trail leg toe elevation and clearance, despite straddling an obstacle for up to 2 min, similar to quadrupeds. Second, we found that when the lead leg was passively moved over an obstacle (eliminating an efference copy signal and altering proprioception) without vision, trail leg toe elevation and clearance were reduced, and variability increased compared with when subjects actively moved their lead leg. Trail leg toe measures returned to normal when vision was provided during the passive manipulation. Finally, we found that altering lead leg proprioceptive feedback by adding mass to the ankle had no effect on trail leg toe measures. Taken together, our results suggest that humans can store a neural representation of obstacle properties for extended periods of time and that vision appears to be sufficient in this process to guide trail leg trajectory.
The representations of reach endpoints in posterior parietal cortex depend on which hand does the reaching
Authors: Chang Steve W. C. , Snyder Lawrence H.
Published: February 2012

Neurons in the parietal reach region (PRR) have been implicated in the sensory-to-motor transformation required for reaching toward visually defined targets. The neurons in each cortical hemisphere might be specifically involved in planning movements of just one limb, or the PRR might code reach endpoints generically, independent of which limb will actually move. Previous work has shown that the preferred directions of PRR neurons are similar for right and left limb movements but that the amplitude of modulation may vary greatly. We now test the hypothesis that frames of reference and eye and hand gain field modulations will, like preferred directions, be independent of which hand moves. This was not the case. Many neurons show clear differences in both the frame of reference as well as in direction and strength of gain field modulations, depending on which hand is used to reach. The results suggest that the information that is conveyed from the PRR to areas closer to the motor output (the readout from the PRR) is different for each limb and that individual PRR neurons contribute either to controlling the contralateral-limb or else bimanual-limb control.
Functional connectivity of the frontal eye fields in humans and macaque monkeys investigated with resting-state fMRI
Authors: Hutchison R. Matthew , Gallivan Jason P. , Culham Jody C. , Gati Joseph S. , Menon Ravi S. , Everling Stefan
Published: February 2012

Although the frontal eye field (FEF) has been identified in macaque monkeys and humans, practical constraints related to invasiveness and task demands have limited a direct cross-species comparison of its functional connectivity. In this study, we used resting-state functional MRI data collected from both awake humans and anesthetized macaque monkeys to examine and compare the functional connectivity of the FEF. A seed region analysis revealed consistent ipsilateral functional connections of the FEF with fronto-parietal cortical areas across both species. These included the intraparietal sulcus, dorsolateral prefrontal cortex, anterior cingulate cortex, and supplementary eye fields. The analysis also revealed greater lateralization of connectivity with the FEF in both hemispheres in humans than in monkeys. Cortical surface-based transformation of connectivity maps between species further corroborated the remarkably similar organization of the FEF functional connectivity. The results support an evolutionarily preserved fronto-parietal system and provide a bridge for linking data from monkey and human studies.
Stability of gait and interlimb coordination in older adults
Authors: Krasovsky T. , Baniña M. C. , Hacmon R. , Feldman A. G. , Lamontagne A. , Levin M. F.
Published: February 2012

Most falls in older adults occur when walking, specifically following a trip. This study investigated the short- and longer term responses of young ( n = 24, 27.6 ± 4.5 yr) and older adults ( n = 18, 69.1 ± 4.2 yr) to a trip during gait at comfortable speed and the role of interlimb coordination in recovery from tripping. Subjects walked on a self-paced treadmill when forward movement of their dominant leg was unexpectedly arrested for 250 ms. Recovery of center of mass (COM) movements and of double-support duration following perturbation was determined. In addition, the disruption and recovery of interlimb coordination of the arms and legs was evaluated. Although young and older subjects used similar lower limb strategies in response to the trip, older adults had less stable COM movement patterns before perturbation, had longer transient destabilization (>25%) after perturbation, required more gait cycles to recover double-support duration (older, 3.48 ± 0.7 cycles; young, 2.88 ± 0.4 cycles), and had larger phase shifts that persisted after perturbation (older, −83° to −90°; young, −39° to −42°). Older adults also had larger disruptions to interlimb coordination of the arms and legs. The timing of the initial disruption in coordination was correlated with the disturbance in gait stability only in young adults. In older adults, greater initial COM instability was related to greater longer term arm incoordination. These results suggest a relationship between interlimb coordination and gait stability, which may be associated with fall risk in older adults. Reduced coordination and gait stability suggest a need for stability-related functional training even in high-functioning older adults.
Adaptation of the preferred human bouncing pattern toward the metabolically optimal frequency
Authors: Merritt Kristen J. , Raburn Caroline E. , Dean Jesse C.
Published: February 2012

Humans often appear to prefer movement patterns that minimize the metabolic energy expenditure of performing a task. However, it is not clear whether this preference is dependent on adaptation to feedback or results from a previously learned motor plan. We recently found that for a bouncing task with an identifiable neuromechanical resonant frequency, humans do not initially prefer to bounce at the resonant frequency despite its presumed metabolic benefits. The purpose of the present study was to determine whether humans adapt their preferred bouncing frequency over time to approach the metabolic optimum. Subjects ( n = 12) performed a series of 6-min reclined bouncing trials while we quantified bounce frequency, metabolic rate, and rate of positive mechanical work performed on the body. In one trial, subjects bounced at their preferred frequency. In five other trials, subjects bounced at frequencies prescribed by a metronome to match specific percentages of their resonant frequency (80–120%). Positive mechanical work rate was held constant across trials by having subjects match real-time visual feedback to a target. The metabolic rate was lowest during prescribed frequency trials near resonance, not during the preferred frequency trial when subjects were free to choose the bouncing frequency. While the initial preferred frequency was lower than the resonant frequency, the preferred frequency gradually approached resonance over the course of 6 min. These results provide evidence that humans do not choose their preferred movement pattern based on an unchanging learned motor plan, but instead adapt their preferred frequency in response to feedback. Our findings may have implications for clinical populations, as reduced sensory acuity could prevent identification of the metabolically optimal movement pattern.
Dynamic Context-Aware and Limited Resources-Aware Service Adaptation for Pervasive Computing
Authors: Miraoui Moeiz , Tadj Chakib , Fattahi Jaouhar , Ben Amar Chokri
Published: February 2012

A pervasive computing system (PCS) requires that devices be context aware in order to provide proactively adapted services according to the current context. Because of the highly dynamic environment of a PCS, the service adaptation task must be performed during device operation. Most of the proposed approaches do not deal with the problem in depth, because they are either not really context aware or the problem itself is not thought to be dynamic. Devices in a PCS are generally hand-held, that is, they have limited resources, and so, in the effort to make them more reliable, the service adaptation must take into account this constraint. In this paper, we propose a dynamic service adaptation approach for a device operating in a PCS that is both context aware and limited resources aware. The approach is then modeled using colored Petri Nets and simulated using the CPN Tools, an important step toward its validation.
Enhancing a Commercial Game Engine to Support Research on Route Realism for Synthetic Human Characters
Authors: Hanold Gregg T. , Petty Mikel D.
Published: February 2012

Generating routes for entities in virtual environments, such as simulated vehicles or synthetic human characters, is a long-standing problem, and route planning algorithms have been developed and studied for some time. Existing route planning algorithms, including the widely used A*algorithm, are generally intended to achieve optimality in some metric, such as minimum length or minimum time. Comparatively little attention has been given to route realism, defined as the similarity of the algorithm-generated route to the route followed by real humans in the same terrain with the same constraints and goals. Commercial game engines have seen increasing use as a context for research. To study route realism in a game engine, two developments were needed: a quantitative metric for measuring route realism and a game engine able to capture route data needed to compute the realism metric. Enhancements for recording route data for both synthetic characters and human players were implemented within the Unreal Tournament 2004 game engine. A methodology for assessing the realism of routes and other behaviors using a quantitative metric was developed. The enhanced Unreal Tournament 2004 game engine and the realism assessment methodology were tested by capturing data required to calculate a metric of route realism.
A Computer Model for the Simulation of Nonspherical Particle Dynamics in the Human Respiratory Tract
Authors: Sturm Robert
Published: February 2012

In the study presented here deposition of spheres and nonspherical particles with various aspect ratios (0.01–100) in the human respiratory tract was theoretically modeled. Shape of the nonspherical particles was considered by the application of the latest aerodynamic diameter concepts. Particle deposition was predicted by using a stochastic model of the lung geometry and simulating particle transport trajectories according to the random-walk algorithm. Concerning fibers total deposition is significantly enhanced with respect to that of spheres for μm-sized particles, whereby at normal breathing conditions peripheral lung compartments serve as primary deposition targets. In the case of oblate disks, total deposition becomes mostly remarkable for submicron particles, with the bronchioli and alveoli being targeted to a high extent. Enhancement of the aerodynamic diameter and/or flow rate generally causes a displacement of deposition maxima from peripheral to more proximal lung regions. From these findings, it can be concluded that these particle classes may represent tremendous occupational hazards, especially if they are attached with radioactive elements or heavy metals.
Antioxidant Activities and Phytochemical Study of Leaf Extracts from 18 Indigenous Tree Species in Taiwan
Authors: Ho Shang-Tse , Tung Yu-Tang , Chen Yong-Long , Zhao Ying-Ying , Chung Min-Jay , Wu Jyh-Horng
Published: February 2012

The objective of this study is to assess antioxidant activities of methanolic extracts from the leaves of 18 indigenous tree species in Taiwan. Results revealed that, among 18 species,Acer oliverianumexhibited the best free radical scavenging activities. The IC50values were 5.8 and 11.8 μg/mL on DPPH radical and superoxide radical scavenging activities, respectively. In addition,A. oliverianumalso exhibited the strongest ferrous ion chelating activity. Based on a bioactivity-guided isolation principle, the resulting methanolic crude extracts ofA. oliverianumleaves were fractionated to yield soluble fractions of hexane, EtOAc, BuOH, and water. Of these, the EtOAc fraction had the best antioxidant activity. Furthermore, 8 specific phytochemicals were isolated and identified from the EtOAc fraction. Among them, 1,2,3,4,6-O-penta-galloyl-β-D-glucopyranose had the best free radical scavenging activity. These results demonstrate that methanolic extracts and their derived phytochemicals ofA. oliverianumleaves have excellent antioxidant activities and thus they have great potential as sources for natural health products.
UAV Formation Flight Based on Nonlinear Model Predictive Control
Authors: Chao Zhou , Zhou Shao-Lei , Ming Lei , Zhang Wen-Guang
Published: February 2012

We designed a distributed collision‐free formation flight control law in the framework of nonlinear model predictive control. Formation configuration is determined in the virtual reference point coordinate system. Obstacle avoidance is guaranteed by cost penalty, and intervehicle collision avoidance is guaranteed by cost penalty combined with a new priority strategy.
Characteristics of Evoked Potential Multiple EEG Recordings in Patients with Chronic Pain by Means of Parallel Factor Analysis
Authors: Wang Juan , Li Xiaoli , Lu Chengbiao , Voss Logan J. , Barnard John P. M. , Sleigh Jamie W.
Published: February 2012

This paper presents an alternative method, called as parallel factor analysis (PARAFAC) with a continuous wavelet transform, to analyze of brain activity in patients with chronic pain in the time-frequency-channel domain and quantifies differences between chronic pain patients and controls in these domains. The event related multiple EEG recordings of the chronic pain patients and non-pain controls with somatosensory stimuli (pain, random pain, touch, random touch) are analyzed. Multiple linear regression (MLR) is applied to describe the effects of aging on the frequency response differences between patients and controls. The results show that the somatosensory cortical responses occurred around 250 ms in both groups. In the frequency domain, the neural response frequency in the pain group (around 4 Hz) was less than that in the control group (around 5.5 Hz) under the somatosensory stimuli. In the channel domain, cortical activation was predominant in the frontal region for the chronic pain group and in the central region for controls. The indices of active ratios were statistical significant between the two groups in the frontal and central regions. These findings demonstrate that the PARAFAC is an interesting method to understanding the pathophysiological characteristics of chronic pain.
Effect of Selenium on HLA-DR Expression of Thyrocytes
Authors: Balázs Csaba , Kaczur Viktória
Published: February 2012

Autoimmune thyroid diseases (ATDs) represent the most frequent forms of the organ-specific autoimmune thyroid disorders that result from interaction between genetic and environmental factors. Selenium has been shown to exert a beneficial effect on the autoimmune thyroiditis. In spite of therapeutical effect of selenium on autoimmunity, the mechanism of its action has not been revealed.Objective. To determine whether selenium in vitro thyrocytes cultures are able to influence the HLA-DR molecule expression of human thyrocytes and production of free oxygen radicals.Method. Thyrocytes were prepared from human thyroid gland and cultured in vitro in the presence of interferon-γand sodium selenite. The expression of HLA-DR molecules induced by interferon-γin the presence of sodium selenite of various concentration was measured by fluorescence-activated cell sorter.Results. Selenium has a dose-dependent inhibitory effect on the expression of HLA-DR molecules of thyrocytes induced by interferon-γ. This effect of selenium was in the inverse correlation with antioxidative capacity.Conclusion. Beneficial effect of selenium on autoimmune mechanism is a complex mechanism in which the inhibitory effect on HLA-DR molecule expression and antioxidative capacity are involved into therapy of autoimmune thyroiditis.
Simple Harmonic Oscillator Equation and Its Hyers-Ulam Stability
Authors: Jung Soon-Mo , Kim Byungbae
Published: February 2012

We solve the inhomogeneous simple harmonic oscillator equation and apply this result to obtain a partial solution to the Hyers-Ulam stability problem for the simple harmonic oscillator equation.
Indoor Off-Body Wireless Communication: Static Beamforming versus Space-Time Coding
Authors: Van Torre Patrick , Scarpello Maria Lucia , Vallozzi Luigi , Rogier Hendrik , Moeneclaey Marc , Vande Ginste Dries , Verhaevert Jo
Published: February 2012

The performance of beamforming versus space-time coding using a body-worn textile antenna array is experimentally evaluated for an indoor environment, where a walking rescue worker transmits data in the 2.45 GHz ISM band, relying on a vertical textile four-antenna array integrated into his garment. The two transmission scenarios considered are static beamforming at low-elevation angles and space-time code based transmit diversity. Signals are received by a base station equipped with a horizontal array of four dipole antennas providing spatial receive diversity through maximum-ratio combining. Signal-to-noise ratios, bit error rate characteristics, and signal correlation properties are assessed for both off-body transmission scenarios. Without receiver diversity, the performance of space-time coding is generally better. In case of fourth-order receiver diversity, beamforming is superior in line-of-sight conditions. For non-line-of-sight propagation, the space-time codes perform better as soon as bit error rates are low enough for a reliable data link.
Interobserver Agreement for Endometrial Cancer Characteristics Evaluated on Biopsy Material
Authors: Nofech-Mozes S. , Ismiil N. , Dubé V. , Saad R. S. , Ghorab Z. , Grin A. , Ackerman I. , Khalifa M. A.
Published: February 2012

A shift toward a disease-based therapy designed according to patterns of failure and likelihood of nodal involvement predicted by pathologic determinants has recently led to considering a selective approach to lymphadenectomy for endometrial cancer. Therefore, it became critical to examine reproducibility of diagnosing the key determinants of risk, on preoperative endometrial tissue samples as well as the concordance between preoperative and postresection specimens. Six gynaecologic pathologists assessed 105 consecutive endometrial biopsies originally reported as positive for endometrial cancer for cell type (endometrioid versus nonendometrioid), tumor grade (FIGO 3-tiered and 2-tiered), nuclear grade, and risk category (low risk defined as endometrioid histology, grade 1 + 2 and nuclear grade <3). Interrater agreement levels were substantial for identification of nonendometrioid histology (κ= 0.63; SE = 0.025), high tumor grade (κ= 0.64; SE = 0.025), and risk category (κ= 0.66; SE = 0.025). The overall agreement was fair for nuclear grade (κ= 0.21; SE = 0.025). There is agreement amongst pathologists in identifying high-risk pathologic determinants on endometrial cancer biopsies, and these highly correlate with postresection specimens. This is ascertainment prerequisite adaptation of the paradigm shift in surgical staging of patients with endometrial cancer.
Protecting Privacy of Shared Epidemiologic Data without Compromising Analysis Potential
Authors: Cologne John , Grant Eric J. , Nakashima Eiji , Chen Yun , Funamoto Sachiyo , Katayama Hiroaki
Published: February 2012

Objective. Ensuring privacy of research subjects when epidemiologic data are shared with outside collaborators involves masking (modifying) the data, but overmasking can compromise utility (analysis potential). Methods of statistical disclosure control for protecting privacy may be impractical for individual researchers involved in small-scale collaborations.Methods. We investigated a simple approach based on measures of disclosure risk and analytical utility that are straightforward for epidemiologic researchers to derive. The method is illustrated using data from the Japanese Atomic-bomb Survivor population.Results. Masking by modest rounding did not adequately enhance security but rounding to remove several digits of relative accuracy effectively reduced the risk of identification without substantially reducing utility. Grouping or adding random noise led to noticeable bias.Conclusions. When sharing epidemiologic data, it is recommended that masking be performed using rounding. Specific treatment should be determined separately in individual situations after consideration of the disclosure risks and analysis needs.
Primary Corneal Squamous Cell Carcinoma in a Dog: Clinical and Histopathological Evaluation
Authors: Barsotti Giovanni , Ressel Lorenzo , Finotello Riccardo , Marchetti Veronica , Millanta Francesca
Published: February 2012

An 8-year-old male pug with a 12-month history of a progressive nonpainful mass on the left cornea was evaluated. Ocular examination showed a severe bilateral keratoconjunctivitis sicca, pigmentary keratitis, and an exophytic irregular pink mass occupying approximately 75% of the total corneal surface of the left eye. A squamous cell carcinoma (SCC) was suspected on cytology, and clinical investigations showed no evidence of metastases. A transpalpebral enucleation was therefore performed, and the diagnosis of SCC was confirmed on histopathology. Immunohistochemical investigations showed that the neoplastic cells were pan-cytokeratin positive and vimentin negative. Additionally, nuclei immunoreactive to Ki-67 antigen were detected. Tumor cells were also negative to p53. Immunoreactivity to COX-2 was found in less than 10% of the neoplastic cells. No adjuvant therapies were instituted, and no evidence of local recurrence or distance metastasis was identified during the 24-month follow-up period.
Human Blood-Vessel-Derived Stem Cells for Tissue Repair and Regeneration
Authors: Chen Chien-Wen , Corselli Mirko , Péault Bruno , Huard Johnny
Published: February 2012

Multipotent stem/progenitor cells with similar developmental potentials have been independently identified from diverse human tissue/organ cultures. The increasing recognition of the vascular/perivascular origin of mesenchymal precursors suggested blood vessels being a systemic source of adult stem/progenitor cells. Our group and other laboratories recently isolated multiple stem/progenitor cell subsets from blood vessels of adult human tissues. Each of the three structural layers of blood vessels: intima, media, and adventitia has been found to include at least one precursor population, that is, myogenic endothelial cells (MECs), pericytes, and adventitial cells (ACs), respectively. MECs and pericytes efficiently regenerate myofibers in injured and dystrophic skeletal muscles as well as improve cardiac function after myocardial infarction. The applications of ACs in vascular remodeling and angiogenesis/vasculogenesis have been examined. Our recent finding that MECs and pericytes can be purified from cryogenically banked human primary muscle cell culture further indicates their potential applications in personalized regenerative medicine.
A Strange Term in the Homogenization of Parabolic Equations with Two Spatial and Two Temporal Scales
Authors: Flodén L. , Holmbom A. , Lindberg M. Olsson
Published: February 2012

We study the homogenization of a parabolic equation with oscillations in both space and time in the coefficienta(x/ε,t/ε2)in the elliptic part and spatial oscillations in the coefficientρ(x/ε)that is multiplied with the time derivative∂tuε. We obtain a strange term in the local problem. This phenomenon appears as a consequence of the combination of the spatial oscillation inρ(x/ε)and the temporal oscillation ina(x/ε,t/ε2)and disappears if either of these oscillations is removed.
Risk Factors for Anemia among Brazilian Infants from the 2006 National Demographic Health Survey
Authors: Konstantyner Tulio , Roma Oliveira Thais Cláudia , de Aguiar Carrazedo Taddei José Augusto
Published: February 2012

Iron deficiency is an important public health problem. An understanding of anemia risk factors is essential to informed health policies. We performed a cross-sectional study of 1,382 infants from the 2006 Brazilian National Survey on Demography and the Health of Women and Children. Mild and moderate anemia was characterised by hemoglobin levels below 11.0 and 9.5 g/dL, respectively. Rates for mild and moderate anemia were 25.9% and 9.9%, respectively. The logistic model included three risk factors for mild anemia—urban residence area (OR=2.5;P=0.004), fever in the past 2 weeks (OR=2.4;P<0.001), and age less than 12 months (OR=1.7;P=0.024). Strategies to control infant anemia should include health promotion and nutritional education for families from all socioeconomic levels. Lifestyle quality improvement based on adequate food consumption must be achieved by communities in all macroregions, and especially in urban areas.
Endobronchial Lipomatous Hamartoma: An Incidental Finding in a Patient with Atrial Fibrillation—A Case Report
Authors: Schneider Friederike , Winter Hauke , Schwarz Florian , Niederhagen Manuel , Arias-Herrera Vivian , Martens Eimo , Kääb Stefan , Theiss Hans
Published: February 2012

Introduction. Lung hamartomas are the most common benign tumors of the lung. Typically, they are located in the peripheral lung, while an endobronchial localisation is rare.Case Presentation. We present a case with the rare diagnosis of an endobronchial hamartoma as incidental finding in a 69-year-old male, caucasian patient with atrial fibrillation. At first admission, the patient’s exertional dyspnea was caused by atrial fibrillation. Relapse of exertional dyspnea in the absence of arrhythmia was due to postobstructive pneumonia caused by an endobronchial hamartoma.Conclusion. Endobronchial tumors such as endobronchial lipoma or hamartoma should be considered as potential causes of exertional dyspnea and thus as differential diagnosis of atrial fibrillation. Although endobronchial hamartomas are benign, resection is recommended to prevent postobstructive lung damage.
The Changing Relationship between Surface Temperatures and Indian Monsoon Rainfall with the Phase of ESI Tendency
Authors: Kakade S. B. , Kulkarni Ashwini
Published: February 2012

Effective Strength Index (ESI) is the relative strength of NAO and SO. ESI tendency is the algebraic difference between April-ESI and January-ESI and it represents the simultaneous evolution of NAO and SO from winter to spring. During positive (negative) phase of ESI tendency, NAO restores positive (negative) phase and SO restores negative (positive) phase before the beginning of summer season. Thus during contrasting phases (positive and negative) of ESI tendency, the evolution of NAO and SO is out of phase. In this paper we have studied the spatial and temporal variability of winter-time temperature field over Europe, Arabian Sea and Bay of Bengal during contrasting phases of ESI tendency. The study reveals that during positive (negative) ESI tendency, smaller (larger) region of Europe is showing significant winter-time cooling (warming) at surface. The relationship between winter-time surface temperature over above regions and Indian summer monsoon rainfall (ISMR) also shows spatial and temporal variability. The probable explanation for this change in the relationship is discussed in the paper. Two sets of temperature parameters for two different phases of ESI tendency are found out. Multiple regression equations are developed for the prediction of ISMR in each phase of ESI tendency. The performance of these equations is also discussed in this paper.
The Aurora Kinase A Inhibitor MLN8237 Enhances Cisplatin-Induced Cell Death in Esophageal Adenocarcinoma Cells
Authors: Sehdev Vikas , Peng DunFa , Soutto Mohammed , Washington M. Kay , Revetta Frank , Ecsedy Jeffrey , Zaika Alexander , Rau Tilman T. , Schneider-Stock Regine , Belkhiri Abbes , El-Rifai Wael
Published: February 2012

Esophageal adenocarcinomas are poorly responsive to chemotherapeutics. This study aimed to determine the levels of Aurora kinase A (AURKA) and the therapeutic potential of MLN8237, an investigational AURKA inhibitor, alone and in combination with cisplatin. Using quantitative real-time PCR, we detected frequent AURKA gene amplification (15 of 34, 44%) and mRNA overexpression (37 of 44, 84%) in esophageal adenocarcinomas (P < 0.01). Immunohistochemical analysis showed overexpression of AURKA in more than two-thirds of esophageal adenocarcinoma tissue samples (92 of 132, 70%; P < 0.001). Using FLO-1, OE19, and OE33 esophageal adenocarinoma cell lines, with constitutive AURKA overexpression and mutant p53, we observed inhibition of colony formation with a single treatment of 0.5 μmol/L MLN8237 (P < 0.05). This effect was further enhanced in combination with 2.5 μmol/L cisplatin (P < 0.001). Twenty-four hours after treatment with the MLN8237 or MLN8237 and cisplatin, cell-cycle analyses showed a sharp increase in the percentage of polyploid cells (P < 0.001). This was followed by an increase in the percentage of cells in the sub-G1 phase at 72 hours, concordant with the occurrence of cell death (P < 0.001). Western blot analysis showed higher induction of TAp73β, PUMA, NOXA, cleaved caspase-3, and cleaved PARP with the combined treatment, as compared with a single-agent treatment. Using xenograft models, we showed an enhanced antitumor role for the MLN8237 and cisplatin combination, as compared with single-agent treatments (P < 0.001). In conclusion, this study shows frequent overexpression of AURKA and suggests that MLN8237 could be an effective antitumor agent, which can be combined with cisplatin for a better therapeutic outcome in esophageal adenocarcinomas. Mol Cancer Ther; 11(3); 763–74. ©2012 AACR.