bluuebunny/crossref_metadata_2025 huggingface dataset:
Measuring the short-range force field above a single molecule with atomic resolution
Authors: Mohn Fabian , Gross Leo , Meyer Gerhard
Published: August 2011

We present a method that enables atomic-resolution measurements of the short-range force field above a single organic admolecule using noncontact atomic force microscopy. We have extended the standard force-mapping technique to be able to measure at close tip–molecule distances, in regions that cannot be accessed by normal constant-height or constant-frequency-shift imaging. Our technique can be used to study the interaction between a well-defined scanning probe tip and an admolecule on the atomic scale and yields atomic resolution of both molecule and substrate. Furthermore, it enables the measurement of constant-frequency-shift topographies of molecules with nonplanar adsorption geometries.
Diffusion limited current in very high aspect ratio Pt needle electrodes
Authors: Hu Jie , Yum Kyungsuk , Tajik Arash , Minary-Jolandan Majid , Bang Jeahoon , Yu Min-Feng
Published: August 2011

A direct-write nanofabrication technique was applied to fabricate high aspect ratio Pt needle electrodes for site specific electrochemistry and electrophysiology. Non-passivated and passivated (with a 10 nm thin insulating film) Pt needles having uniform radii as small as 100 nm and lengths over 30 μm were deposited on the exposed conductive ends of ultramicroelectrodes to form extended needle electrodes. Diffusion limited current and its dependence on the radius of the Pt needle were measured with linear sweep voltammetry. Model fittings validated the function of such needle electrodes for effective microscale electrochemical studies and potentially electrophysiological applications.
Modification of spontaneous emission rates in single colloidal CdSe/ZnS quantum dots by a submicron-sized dielectric disk
Authors: Yuan C. T. , Wang Y. C. , Yang Y. C. , Wu M. C. , Tang Jau , Shih M. H.
Published: August 2011

The spontaneous emission (SE) of light sources can be modified externally by surrounding local density of optical states. Here, the SE of single colloidal CdSe/ZnS quantum dots (QDs) coupled to dielectric disks with sub-micrometer sizes was investigated. Using single-QD measurement, the radiative decay rates can be extracted based on time-tagged, time-resolved measurement. In this case, up to ∼6-fold enhancement of the SE rate was observed when single QDs were located on the disk edge. In addition, the photon statistic was found to exhibit photon anti-bunching behavior with much narrowing linewidth, indicating single-photon emission via fast radiative decay process.
Acoustic guiding and subwavelength imaging with sharp bending by sonic crystal
Authors: Li Bo , Deng Ke , Zhao Heping
Published: August 2011

A sharp bending scheme for the self-collimation of acoustic waves is proposed by simply truncating the sonic crystals. An all-angle and wide-band 90°-bending wave guide is demonstrated with nearly perfect transmissions for Gaussian beams at a wide range of incident angles. A 90°-bended imaging for a point source with a subwavelength resolution of 0.37 λ0 is also realized by the proposed structure. These results will find applicability in the manipulation of acoustic waves by sonic crystals.
Molecular dynamics simulations of oxide memristors: Crystal field effects
Authors: Savel’ev S. E. , Alexandrov A. S. , Bratkovsky A. M. , Stanley Williams R.
Published: August 2011

We present molecular-dynamic simulations of memory resistors (memristors) including the crystal field effects on mobile ionic species such as oxygen vacancies appearing during operation of the device. Vacancy distributions show different patterns depending on the ratio of a spatial period of the crystal field to a characteristic radius of the vacancy-vacancy interaction. There are signatures of the orientational order and of spatial voids in the vacancy distributions for some crystal field potentials. The crystal field stabilizes the patterns after they are formed, resulting in a non-volatile switching of the simulated devices.
Ultrafast 2D IR anisotropy of water reveals reorientation during hydrogen-bond switching
Authors: Ramasesha Krupa , Roberts Sean T. , Nicodemus Rebecca A. , Mandal Aritra , Tokmakoff Andrei
Published: August 2011

Rearrangements of the hydrogen bond network of liquid water are believed to involve rapid and concerted hydrogen bond switching events, during which a hydrogen bond donor molecule undergoes large angle molecular reorientation as it exchanges hydrogen bonding partners. To test this picture of hydrogen bond dynamics, we have performed ultrafast 2D IR spectral anisotropy measurements on the OH stretching vibration of HOD in D2O to directly track the reorientation of water molecules as they change hydrogen bonding environments. Interpretation of the experimental data is assisted by modeling drawn from molecular dynamics simulations, and we quantify the degree of molecular rotation on changing local hydrogen bonding environment using restricted rotation models. From the inertial 2D anisotropy decay, we find that water molecules initiating from a strained configuration and relaxing to a stable configuration are characterized by a distribution of angles, with an average reorientation half-angle of 10°, implying an average reorientation for a full switch of ≥20°. These results provide evidence that water hydrogen bond network connectivity switches through concerted motions involving large angle molecular reorientation.
Dispersion of denatured carbon nanotubes by using a dimethylformamide solution
Authors: Nguyen Thi Thuy , Nguyen Sy Uan , Phuong Dinh Tam , Nguyen Duc Chien , Mai Anh Tuan
Published: August 2011

The dispersion of carbon nanotubes (CNTs) in liquid plays an important role in fundamental research and applied science. The most common technique applied to disperse CNTs is ultrasonication. The surfactants used for CNT dispersion are ethanol, sodium dodecyl benzenesulfonate (SDBS), dodecyltrimethylammonium bromide (DATB), sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (NaDDBS). This paper presents the dispersion of denatured CNTs by using a dimethylformamide (DMF) solution. The DMF is adsorbed on the surface of the nanotubes by a hydrophobic or π–π interaction. Ultrasonication helps DMF debundle the nanotubes by Coulombic or hydrophilic interaction, allowing the Van der Waals forces among the individual nanotubes to be overcome. UV–Vis spectra of dispersed CNTs in solution showed a maximum at 260 nm and decreased from UV to near IR. The vibration properties of the carbon samples were characterized with Raman spectroscopy, which illustrated the D and G bands of denatured CNTs at 1354 and 1581 cm−1, respectively, different from the values of 1352 cm−1 and 1580 cm−1, respectively, for undenatured CNTs. Finally, the interaction between surfactants and nanotubes was studied by Fourier transform infrared spectroscopy (FTIR).
Post-critically finite fractal and Martin boundary
Authors: Ju Hongbing , Lau Ka-Sing , Wang Xiang-Yang
Published: August 2011

For an iterated function system (IFS), which we call simple post critically finite, we introduce a Markov chain on the corresponding symbolic space and study its boundary behavior. We carry out some fine estimates of the Martin metric and use them to prove that the Martin boundary can be identified with the invariant set (fractal) of the IFS. This enables us to bring in the boundary theory of Markov chains and the discrete potential theory on this class of fractal sets.
Trs65p, a subunit of the Ypt1p GEF TRAPPII, interacts with the Arf1p exchange factor Gea2p to facilitate COPI-mediated vesicle traffic
Authors: Chen Shuliang , Cai Huaqing , Park Sei-Kyoung , Menon Shekar , Jackson Catherine L. , Ferro-Novick Susan
Published: August 2011

The TRAPP complexes are multimeric guanine exchange factors (GEFs) for the Rab GTPase Ypt1p. The three complexes (TRAPPI, TRAPPII, and TRAPPIII) share a core of common subunits required for GEF activity, as well as unique subunits (Trs130p, Trs120p, Trs85p, and Trs65p) that redirect the GEF from the endoplasmic reticulum–Golgi pathway to different cellular locations where TRAPP mediates distinct membrane trafficking events. Roles for three of the four unique TRAPP subunits have been described before; however, the role of the TRAPPII-specific subunit Trs65p has remained elusive. Here we demonstrate that Trs65p directly binds to the C-terminus of the Arf1p exchange factor Gea2p and provide in vivo evidence that this interaction is physiologically relevant. Gea2p and TRAPPII also bind to the yeast orthologue of the γ subunit of the COPI coat complex (Sec21p), a known Arf1p effector. These and previous findings reveal that TRAPPII is part of an Arf1p GEF-effector loop that appears to play a role in recruiting or stabilizing TRAPPII to membranes. In support of this proposal, we show that TRAPPII is more soluble in an arf1Δ mutant.
Heat shock factor 2 is required for maintaining proteostasis against febrile-range thermal stress and polyglutamine aggregation
Authors: Shinkawa Toyohide , Tan Ke , Fujimoto Mitsuaki , Hayashida Naoki , Yamamoto Kaoru , Takaki Eiichi , Takii Ryosuke , Prakasam Ramachandran , Inouye Sachiye , Mezger Valerie , Nakai Akira
Published: August 2011

Heat shock response is characterized by the induction of heat shock proteins (HSPs), which facilitate protein folding, and non-HSP proteins with diverse functions, including protein degradation, and is regulated by heat shock factors (HSFs). HSF1 is a master regulator of HSP expression during heat shock in mammals, as is HSF3 in avians. HSF2 plays roles in development of the brain and reproductive organs. However, the fundamental roles of HSF2 in vertebrate cells have not been identified. Here we find that vertebrate HSF2 is activated during heat shock in the physiological range. HSF2 deficiency reduces threshold for chicken HSF3 or mouse HSF1 activation, resulting in increased HSP expression during mild heat shock. HSF2-null cells are more sensitive to sustained mild heat shock than wild-type cells, associated with the accumulation of ubiquitylated misfolded proteins. Furthermore, loss of HSF2 function increases the accumulation of aggregated polyglutamine protein and shortens the lifespan of R6/2 Huntington's disease mice, partly through αB-crystallin expression. These results identify HSF2 as a major regulator of proteostasis capacity against febrile-range thermal stress and suggest that HSF2 could be a promising therapeutic target for protein-misfolding diseases.
GlobalMIT: learning globally optimal dynamic bayesian network with the mutual information test criterion
Authors: Vinh Nguyen Xuan , Chetty Madhu , Coppel Ross , Wangikar Pramod P.
Published: August 2011

Motivation: Dynamic Bayesian networks (DBN) are widely applied in modeling various biological networks including the gene regulatory network (GRN). Due to the NP-hard nature of learning static Bayesian network structure, most methods for learning DBN also employ either local search such as hill climbing, or a meta stochastic global optimization framework such as genetic algorithm or simulated annealing.

Results: This article presents GlobalMIT, a toolbox for learning the globally optimal DBN structure from gene expression data. We propose using a recently introduced information theoretic-based scoring metric named mutual information test (MIT). With MIT, the task of learning the globally optimal DBN is efficiently achieved in polynomial time.

Availability: The toolbox, implemented in Matlab and C++, is available at http://code.google.com/p/globalmit.

Contact:  vinh.nguyen@monash.edu; madhu.chetty@monash.edu

Supplementary information:  Supplementary data is available at Bioinformatics online.
A comprehensively molecular haplotype-resolved genome of a European individual
Authors: Suk Eun-Kyung , McEwen Gayle K. , Duitama Jorge , Nowick Katja , Schulz Sabrina , Palczewski Stefanie , Schreiber Stefan , Holloway Dustin T. , McLaughlin Stephen , Peckham Heather , Lee Clarence , Huebsch Thomas , Hoehe Margret R.
Published: August 2011

Independent determination of both haplotype sequences of an individual genome is essential to relate genetic variation to genome function, phenotype, and disease. To address the importance of phase, we have generated the most complete haplotype-resolved genome to date, “Max Planck One” (MP1), by fosmid pool-based next generation sequencing. Virtually all SNPs (>99%) and 80,000 indels were phased into haploid sequences of up to 6.3 Mb (N50 ∼1 Mb). The completeness of phasing allowed determination of the concrete molecular haplotype pairs for the vast majority of genes (81%) including potential regulatory sequences, of which >90% were found to be constituted by two different molecular forms. A subset of 159 genes with potentially severe mutations in either cis or trans configurations exemplified in particular the role of phase for gene function, disease, and clinical interpretation of personal genomes (e.g., BRCA1). Extended genomic regions harboring manifold combinations of physically and/or functionally related genes and regulatory elements were resolved into their underlying “haploid landscapes,” which may define the functional genome. Moreover, the majority of genes and functional sequences were found to contain individual or rare SNPs, which cannot be phased from population data alone, emphasizing the importance of molecular phasing for characterizing a genome in its molecular individuality. Our work provides the foundation to understand that the distinction of molecular haplotypes is essential to resolve the (inherently individual) biology of genes, genomes, and disease, establishing a reference point for “phase-sensitive” personal genomics. MP1's annotated haploid genomes are available as a public resource.
Egg hormones in a highly fecund vertebrate: do they influence offspring social structure in competitive conditions?
Authors: Burton Tim , Hoogenboom M. O. , Armstrong J. D. , Groothuis T. G. G. , Metcalfe N. B.
Published: August 2011

1. Social status can vary considerably among individuals and has significant implications for performance. In addition to a genetic component, social status may be influenced by environmental factors including maternal effects such as prenatal hormone exposure. Maternal effects on traits determining social status have previously been examined in species where mothers provide parental care for relatively few offspring and therefore directly influence postnatal development. However, the generality of conclusions arising from these investigations is unclear because species that employ different reproductive strategies have not been studied.

2. We investigated the hypothesis that egg steroid hormone levels influence the social status of juvenile brown trout (Salmo trutta). We manipulated intra‐clutch levels of cortisol and testosterone in eggs from 15 mothers using dilute hormone baths at the time of fertilization and examined their effects on traits that correlate with social status in juveniles [including standard body size, aggression, competitive ability and standard metabolic rate (SMR)].

3. Hormone treatment did not affect whole‐animal or mass‐corrected SMR at the critical developmental stage when juveniles switch from reliance on a maternally provisioned yolk sac to independent feeding. However, juveniles from cortisol‐treated eggs were smaller at this developmental stage. They were also less aggressive than, and subordinate to, fish from untreated eggs in socially competitive conditions, even after correcting for the observed effect of cortisol on body size. Egg testosterone treatment resulted in a likely pharmacological or toxicological dose with subsequent effects on both body size and behaviour in independently feeding juveniles.

4. Results from this study demonstrate that variation in the amount of cortisol deposited in eggs by spawning females influences juvenile social status and performance. The effects of elevated egg cortisol in fish are similar to the actions of embryonic glucocorticoids reported in other vertebrate taxa with very different reproductive strategies, suggesting a widespread mechanism for the effects of maternal stress on offspring. Possible adaptive aspects of this relationship are discussed.
The presence of sheep leads to increases in plant diversity and reductions in the impact of deer on heather
Authors: DeGabriel Jane L. , Albon Steve D. , Fielding Deborah A. , Riach David J. , Westaway Sally , Irvine R. Justin
Published: August 2011

1. Grazing has been implicated in the decline of heather‐dominated moorlands in Britain, but there has been little consideration of the effects of different species of herbivores on plant diversity. Sheep stocks have recently decreased in Scotland, and quantification of how this affects biodiversity is essential for understanding how different grazing regimes modify upland habitats.

2. We investigated the effects of grazing on plant biodiversity in heather/grass mosaics at 16 upland sites in Scotland. Red deer Cervus elaphus L. were present at all sites, but sheep Ovis aries L. had been removed from half of the sites. Our experimental design incorporated replication at three spatial scales, from a landscape level down to 10 × 10 m plots.

3. We quantified the relative effects of different herbivore species, vegetation structure and rainfall on heather utilisation, species richness and evenness (alpha diversity; Shannon–Wiener index) and beta diversity.

4. At all spatial scales, deer dung counts were higher and heather was shorter when sheep were absent. Furthermore, utilisation of heather was positively correlated with the amount of deer dung, the amount of grass present and smooth grass height.

5. Alpha diversity was consistently positively correlated with the relative amount of grass, but was also positively related to the amount of sheep dung at the largest spatial scale. At the finest scale, alpha diversity was negatively correlated with the amount of deer dung. Beta diversity was higher when sheep were present at all scales.

6. Synthesis and applications. Mixed grazing by sheep and deer appears to be beneficial for increasing both alpha and beta diversity and minimizing damage to heather in the uplands. The absence of sheep is likely to result in expanding deer populations and greater impact on heather. Management of grazing herbivores is an important tool for maintaining biodiversity in many ecosystems. Our results indicate that reducing livestock may alter the impacts of wild grazers on their habitats and drive changes in diversity, whereas mixed grazing can enhance habitat quality and maintain plant diversity. Therefore, this effect should be considered when devising policy recommendations.
Brain region‐specific gene expression changes after chronic intermittent ethanol exposure and early withdrawal in C57BL/6J mice
Authors: Melendez Roberto I. , McGinty Jacqueline F. , Kalivas Peter W. , Becker Howard C.
Published: August 2011

Neuroadaptations that participate in the ontogeny of alcohol dependence are likely a result of altered gene expression in various brain regions. The present study investigated brain region‐specific changes in the pattern and magnitude of gene expression immediately following chronic intermittent ethanol (CIE) exposure and 8 hours following final ethanol exposure [i.e. early withdrawal (EWD)]. High‐density oligonucleotide microarrays (Affymetrix 430A 2.0, Affymetrix, Santa Clara, CA, USA) and bioinformatics analysis were used to characterize gene expression and function in the prefrontal cortex (PFC), hippocampus (HPC) and nucleus accumbens (NAc) of C57BL/6J mice (Jackson Laboratories, Bar Harbor, ME, USA). Gene expression levels were determined using gene chip robust multi‐array average followed by statistical analysis of microarrays and validated by quantitative real‐time reverse transcription polymerase chain reaction and Western blot analysis. Results indicated that immediately following CIE exposure, changes in gene expression were strikingly greater in the PFC (284 genes) compared with the HPC (16 genes) and NAc (32 genes). Bioinformatics analysis revealed that most of the transcriptionally responsive genes in the PFC were involved in Ras/MAPK signaling, notch signaling or ubiquitination. In contrast, during EWD, changes in gene expression were greatest in the HPC (139 genes) compared with the PFC (four genes) and NAc (eight genes). The most transcriptionally responsive genes in the HPC were involved in mRNA processing or actin dynamics. Of the few genes detected in the NAc, the most representatives were involved in circadian rhythms. Overall, these findings indicate that brain region‐specific and time‐dependent neuroadaptive alterations in gene expression play an integral role in the development of alcohol dependence and withdrawal.
Periadolescent amphetamine treatment causes transient cognitive disruptions and long‐term changes in hippocampal LTP depending on the endogenous expression of pleiotrophin
Authors: Gramage Esther , Del Olmo Nuria , Fole Alberto , Martín Yasmina B. , Herradón Gonzalo
Published: August 2011

Amphetamine treatment during adolescence causes long‐term cognitive deficits in rats. Pleiotrophin (PTN) is a cytokine with important roles in the modulation of synaptic plasticity, whose levels of expression are significantly regulated by amphetamine administration. To test the possibility that the long‐term consequences of periadolescent amphetamine treatment cross species and, furthermore, to test the hypothesis that PTN could be one of the factors involved in the adult cognitive deficits observed after periadolescent amphetamine administrations, we comparatively studied the long‐term consequences of periadolescent amphetamine treatment (3 mg/kg intraperitoneal, daily during 10 days) in normal wild‐type (PTN+/+) and in PTN genetically deficient (PTN−/−) mice. Within the first week after cessation of treatment, significant deficits in the passive avoidance and Y‐maze tests were only observed in amphetamine‐pretreated PTN−/− mice. However, 13 and 26 days after the last administration, we did not find significant differences in Y‐maze between amphetamine‐ and saline‐pretreated PTN−/− mice. In addition, we did not find any genotype‐ or treatment‐related anxiogenic‐ or depressive‐like behaviour in adult mice. Furthermore, we observed a significantly enhanced long‐term potentiation (LTP) in CA1 hippocampal slices from saline‐pretreated PTN−/− mice compared with saline‐pretreated PTN+/+ mice. Interestingly, amphetamine pre‐treatment during adolescence significantly enhanced LTP in adult PTN+/+ mice but did not cause any effect in PTN−/− mice, suggesting LTP mechanisms saturation in naïve PTN−/− mice. The data demonstrate that periadolescent amphetamine treatment causes transient cognitive deficits and long‐term alterations of hippocampal LTP depending on the endogenous expression of PTN.
Optimising Perceived Distortion in Lossy Encoding of Dynamic Meshes
Authors: Váša L. , Petřík O.
Published: August 2011

Development of geometry data compression techniques in the past years has been limited by the lack of a metric with proven correlation with human perception of mesh distortion. Many algorithms have been proposed, but usually the aim has been to minimise mean squared error, or some of its derivatives.

In the field of dynamic mesh compression, the situation has changed with the recent proposal of the STED metric, which has been shown to capture the human perception of mesh distortion much better than previous metrics. In this paper we show how existing algorithms can be steered to provide optimal results with respect to this metric, and we propose a novel dynamic mesh compression algorithm, based on trajectory space PCA and Laplacian coordinates, specifically designed to minimise the newly proposed STED error. Our experiments show that using the proposed algorithm, we were able to reduce the required data rate by up to 50% while preserving the introduced STED error.
An Optimization Approach to Improving Collections of Shape Maps
Authors: Nguyen Andy , Ben‐Chen Mirela , Welnicka Katarzyna , Ye Yinyu , Guibas Leonidas
Published: August 2011

Finding an informative, structure‐preserving map between two shapes has been a long‐standing problem in geometry processing, involving a variety of solution approaches and applications. However, in many cases, we are given not only two related shapes, but a collection of them, and considering each pairwise map independently does not take full advantage of all existing information. For example, a notorious problem with computing shape maps is the ambiguity introduced by the symmetry problem — for two similar shapes which have reflectional symmetry there exist two maps which are equally favorable, and no intrinsic mapping algorithm can distinguish between them based on these two shapes alone. Another prominent issue with shape mapping algorithms is their relative sensitivity to how “similar” two shapes are — good maps are much easier to obtain when shapes are very similar. Given the context of additional shape maps connecting our collection, we propose to add the constraint of global map consistency, requiring that any composition of maps between two shapes should be independent of the path chosen in the network. This requirement can help us choose among the equally good symmetric alternatives, or help us replace a “bad” pairwise map with the composition of a few “good” maps between shapes that in some sense interpolate the original ones. We show how, given a collection of pairwise shape maps, to define an optimization problem whose output is a set of alternative maps, compositions of those given, which are consistent, and individually at times much better than the original. Our method is general, and can work on any collection of shapes, as long as a seed set of good pairwise maps is provided. We demonstrate the effectiveness of our method for improving maps generated by state‐of‐the‐art mapping methods on various shape databases.
Deformable 3D Shape Registration Based on Local Similarity Transforms
Authors: Papazov C. , Burschka D.
Published: August 2011

In this paper, a new method for deformable 3D shape registration is proposed. The algorithm computes shape transitions based on local similarity transforms which allows to model not only as‐rigid‐as‐possible deformations but also local and global scale. We formulate an ordinary differential equation (ODE) which describes the transition of a source shape towards a target shape. We assume that both shapes are roughly pre‐aligned (e.g., frames of a motion sequence). The ODE consists of two terms. The first one causes the deformation by pulling the source shape points towards corresponding points on the target shape. Initial correspondences are estimated by closest‐point search and then refined by an efficient smoothing scheme. The second term regularizes the deformation by drawing the points towards locally defined rest positions. These are given by the optimal similarity transform which matches the initial (undeformed) neighborhood of a source point to its current (deformed) neighborhood. The proposed ODE allows for a very efficient explicit numerical integration. This avoids the repeated solution of large linear systems usually done when solving the registration problem within general‐purpose non‐linear optimization frameworks. We experimentally validate the proposed method on a variety of real data and perform a comparison with several state‐of‐the‐art approaches.
Multiscale Biharmonic Kernels
Authors: Rustamov Raif M.
Published: August 2011

This paper introduces a general principle for constructing multiscale kernels on surface meshes, and presents a construction of the multiscale pre‐biharmonic and multiscale biharmonic kernels. Our construction is based on an optimization problem that seeks to minimize a smoothness criterion, the Laplacian energy, subject to a sparsity inducing constraint. Namely, we use the lasso constraint, which sets an upper bound on the l1 ‐norm of the solution, to obtain a family of solutions parametrized by this upper‐bound parameter. The interplay between sparsity and smoothness results in smooth kernels that vanish away from the diagonal. We prove that the resulting kernels have gradually changing supports, consistent behavior over partial and complete meshes, and interesting limiting behaviors (e.g. in the limit of large scales, the multiscale biharmonic kernel converges to the Green's function of the biharmonic equation); in addition, these kernels are based on intrinsic quantities and so are insensitive to isometric deformations. We show empirically that our kernels are shape‐aware, are robust to noise, tessellation, and partial object, and are fast to compute. Finally, we demonstrate that the new kernels can be useful for function interpolation and shape correspondence.
FIRM LOCATION: FIRM COMPETENCES, FINANCIAL STRUCTURE AND REGIONAL DETERMINANTS
Authors: Kottaridi Constantina , Lioukas Spyros
Published: August 2011

This paper examines the choice of firms to locate in particular regions based on an expanded set of decision making determinants which takes into consideration firm profiles and competences, firm characteristics with particular emphasis on their financial structure and attractive regional factors focusing on knowledge. It combines intuitions from industrial economics, spatial analysis, corporate finance theory and strategic management to explore in greater depth the location of entrepreneurial activities at the sub‐national level of regions, in particular between large urban areas and the periphery. Results suggest that the firm competences are conducive to their location and that other firm attributes contribute to this decision. When regional development and technological sophistication is taken into account, it is evidenced that they act as catalysts to the above decision, though only with respect to metropolitan regions where economies of scale could be exploited.
AGGLOMERATION AND GROWTH WITH ENDOGENOUS EXPENDITURE SHARES*
Authors: Cerina Fabio , Mureddu Francesco
Published: August 2011

ABSTRACT We develop a New Economic Geography and Growth model which, by using a CES utility function in the second‐stage optimization problem, allows for expenditure shares in industrial goods to be endogenously determined. The implications of our generalization are quite relevant. In particular, we obtain the following novel results: (1) two additional nonsymmetric interior steady states emerge for some intermediate values of trade costs. These steady‐states are stable if the industrial and the traditional goods are either good or very poor substitutes, while they are unstable for intermediate (yet lower than one) values of the intersectoral elasticity of substitution. In the latter case, the model displays three interior steady states—the symmetric and the core‐periphery allocations—which are stable at the same time; (2) agglomeration processes may always take place, whatever the degree of market integration, provided that the traditional and the industrial goods are sufficiently good substitutes; (3) the regional rate of growth is affected by the interregional allocation of economic activities even in the absence of localized spillovers, so that geography always matters for growth and (4) the regional rate of growth is affected by the degree of market openness: in particular, depending on whether the traditional and the industrial goods are good or poor substitutes, economic integration may be, respectively, growth‐enhancing or growth‐detrimental.
Role Conflict and Self‐Efficacy Among Employed Parents: Examining Complex Statistical Interactions
Authors: Houle Lucie , Chiocchio François , Favreau Olga E. , Villeneuve Martine
Published: August 2011

In response to growing concerns with explaining how work and family interfere with each other and with statistical approaches that do not capture the way in which predictors interact, this study tested statistical interactions involving personal and social resources of 410 full‐time employed women and men. The results indicate that self‐efficacy is a strong predictor of family interfering with work (FIW) and work interfering with family (WIF). Gender moderates the relation between supervisor support and WIF moderates the impact of efficacy beliefs and instrumental support at home on FIW. Specifically, while supervisor support is negatively related to WIF in women and men, high levels of support more strongly affected men's perceptions of WIF. In low self‐efficacy men, high levels of support at home improved their perceptions of FIW but these perceptions worsened in women. These findings contrast with earlier research that focus predominantly on the predictive value of structural demands (for example, the number of hours worked per week and family size). This study shows that gender plays a critical yet intricate role as a predictor of the successful management of work and family roles: it is not gender per se but its interaction with personal and social variables that informs us about differences in the experience of employed parents.
Current psoriasis treatments in an Italian population and their association with socio‐demographical and clinical features
Authors: Altobelli E. , Marziliano C. , Fargnoli M.C. , Petrocelli R. , Maccarone M. , Chimenti S. , Peris K.
Published: August 2011

Background  Patient adherence is a key element for therapeutic success and represents a major concern for all healthcare professionals.

Objective  Aim of our study was to assess the frequency of use of treatments currently available for psoriasis and its association with specific socio‐demographical and clinical variables.

Methods  The study population consisted of 1689 patients, aged 12–85 years. Information concerning socio‐demographical variables, clinical features and the type of current treatment was collected. Items on patients’ satisfaction of current treatments and of dermatologist‐patient relationship were also included. The chi‐squared test was used to estimate the association between the categorical variables, whereas Wilcoxon and Kruskal–Wallis tests were applied to the interval and ordinal variables. The Cochran–Mantel–Haenszel chi‐squared trend test was used to evaluate the degree of satisfaction related to dermatologist–patient relationship.

Results  Of the 1689 psoriatic patients, 54.1% did not use any treatments and 45.9% used at least one treatment. The use of drugs was significantly associated exclusively to severity of disease and affected body surface area. Systemic therapies, both traditional treatments and biological agents, were mainly used in patients with disease duration >10 years and disease severity. Treatment adherence was significantly associated to the degree of patient’s satisfaction of his/her relationship with the dermatologist. Alternative treatment such as over the counter medications and acupuncture were used by 33% of patients.

Conclusion  The majority of psoriatic patients do not use any treatments. However, treatment adherence significantly increases when dermatologists clarify the treatment schedule, inform patients and meet the patients’ needs.
The Swedish APP mutation alters the effect of genetically reduced BACE1 expression on the APP processing
Authors: Rabe Sabine , Reichwald Julia , Ammaturo Domenico , de Strooper Bart , Saftig Paul , Neumann Ulf , Staufenbiel Matthias
Published: August 2011

J. Neurochem. (2011) 119, 231–239.

Inhibition of β‐secretase (BACE1) is a key therapeutic approach in Alzheimer’s disease (AD), as BACE1 initiates amyloid‐β (Aβ) cleavage from the β‐amyloid precursor protein (APP). As Aβ reductions in mice lacking one BACE1 allele diverged considerably between studies we investigated the effect of BACE1 knock‐out in more detail. With both BACE1 alleles the Swedish mutation (APP23 mice) increased APP processing and shifted it towards the β‐secretase pathway as compared with non‐mutated APP expressed at a similar level (APP51/16 mice). This effect was much smaller then observed in cell culture. An about 50% decrease in BACE1 enzyme activity resulted in a sub‐proportional Aβ reduction with the Swedish mutation (−20%) and even less for non‐mutated APP (−16%). In wild‐type mice, the Aβ reduction may be even further diminished. Other metabolites of the β‐secretase pathway decreased accordingly while the alternative α‐secretase pathway increased. Complete BACE1 deletion strongly enhanced these changes. The remaining Aβ signal also described by others can be explained by assay cross‐reactivity with other APP metabolites supporting BACE1 as the major β‐secretase. Our data indicate that BACE1 is in excess over APP at the cleavage site(s). Alterations in APP expression or substrate properties, therefore, quantitatively change its cleavage and Aβ generation.
Adaptations to aerobic interval training: interactive effects of exercise intensity and total work duration
Authors: Seiler S. , Jøranson K. , Olesen B. V. , Hetlelid K. J.
Published: August 2011

To compare the effects of three 7‐week interval training programs varying in work period duration but matched for effort in trained recreational cyclists. Thirty‐five cyclists (29 male, 6 female, VO2peak 52 ± 6 mL kg/min) were randomized to four training groups with equivalent training the previous 2 months (∼6 h/wk, ∼1.5 int. session/wk). Low only (n=8) trained 4–6 sessions/wk at a low‐intensity. Three groups (n=9 each) trained 2 sessions/wk × 7 wk: 4 × 4 min, 4 × 8 min, or 4 × 16 min, plus 2–3 weekly low‐intensity bouts. Interval sessions were prescribed at the maximal tolerable intensity. Interval training was performed at 88 ± 2, 90 ± 2, and 94 ± 2% of HRpeak and 4.9, 9.6, and 13.2 mmol/L blood lactate in 4 × 16, 4 × 8, and 4 × 4 min groups, respectively (both P<0.001). 4 × 8min training induced greater overall gains in VO2peak, power@VO2peak, and power@4 mM bLa‐ (Mean ± 95%CI): 11.4 (8.0–14.9), vs 4.2 (0.4–8.0), 5.6 (2.1–9.1), and 5.5% (2.0–9.0) in Low, 4 × 16, and 4 × 4 min groups, respectively (P<0.02 for 4 × 8 min vs all other groups). Interval training intensity and accumulated duration interact to influence the adaptive response. Accumulating 32 min of work at 90% HR max induces greater adaptive gains than accumulating 16 min of work at ∼95% HR max despite lower RPE.
Marginal Bone‐Level Alterations at Implants Installed in Block versus Particulate Onlay Bone Grafts Mixed with Platelet‐Rich Plasma in Atrophic Maxilla. A Prospective 5‐Year Follow‐Up Study of 15 Patients
Authors: Dasmah Amir , Thor Andreas , Ekestubbe Annika , Sennerby Lars , Rasmusson Lars
Published: August 2011

Background: Extensive atrophy of the alveolar process may require a bone‐grafting procedure prior to implant treatment. Autogenous bone grafts from the iliac crest, used as onlay block and particulate bone, have been used together with sinus‐lift procedure in order to rehabilitate patients with extremely resorbed maxillae. However, there are to our knowledge no 5‐year follow‐up studies evaluating the extent of bone‐level change in patients treated with respectively block and particulate autogenous bone grafts.

Purpose: The purpose of this prospective clinical study was to conduct a 5‐year follow‐up analysis with focus on bone‐level alteration in block versus particulate onlay bone grafts.

Material and Methods: Fifteen out of originally 19 patients who were treated with iliac bone grafts and oral implants in the maxilla have been followed through the first 5 postoperative years. In a first study conducted on 19 patients, the role of platelet‐rich plasma in conjunction with autogenous bone was evaluated. In this 5‐year follow‐up study, the marginal bone alterations have been documented at base line, 1 year and 5 years of loading to the nearest 0,1 mm at mesial and distal surfaces of the implants. Two implants were installed on each side of the midline in either block or particulate bone grafts giving test and control sides in each patient. Additionally, two implants on each side were installed in residual bone/grafted sinus floor.

Result: Marginal bone alteration in the anterior maxilla appeared larger at the side augmented by block bone at baseline, and after 1 and 5 years of loading, but the change was not statistically significant. Moreover, there was a significantly higher degree of marginal alteration during the first year of loading, compared with the examinations after 5 years.

Conclusion: The present follow‐up study showed that there is no significant difference in the extension of resorption between block‐ and particulate autogenous bone grafts over a 5‐year period. Most of the resorption occurred during the first year in function.
Phosphodiesterase Type 5 Expression in Human and Rat Lower Urinary Tract Tissues and the Effect of Tadalafil on Prostate Gland Oxygenation in Spontaneously Hypertensive Rats
Authors: Morelli Annamaria , Sarchielli Erica , Comeglio Paolo , Filippi Sandra , Mancina Rosa , Gacci Mauro , Vignozzi Linda , Carini Marco , Vannelli Gabriella B. , Maggi Mario
Published: August 2011

Introduction

In humans, prostate phosphodiesterase type 5 inhibitors (PDE5) expression was prominently localized in the endothelial and smooth muscle cells of the vascular bed, suggesting a possible action of PDE5 inhibitors (PDE5i) on prostate blood flow.

Aim

To investigate PDE5 expression in human and rat lower urinary tract (LUT) tissues, including vasculature, and determine the effects of PDE5 inhibition with tadalafil on prostatic blood perfusion.

Main Outcome Measures

Human vesicular-deferential arteries (which originate from the inferior vesical artery, the main arterial source of blood supply to the bladder and prostate) were analyzed for PDE5 expression and activity. The effects of tadalafil on prostate oxygenation were studied in spontaneously hypertensive rats (SHR), characterized by ischemia/hypoxia of the genitourinary tract.

Methods

PDE5 expression was evaluated by quantitative reverse transcription-polymerase chain reaction and immunohistochemistry. SHR were treated with tadalafil (2 mg/kg/day) for 1, 7, or 28 days and compared with untreated SHR and the unaffected counterpart Wistar-Kyoto (WKY) rats. Prostate oxygenation was detected by Hypoxyprobe-1 and hypoxia markers (hypoxia-inducible factor-1α[HIF-1α] and endothelin-1 type B [ETB]) immunostaining.

Results

Human vesicular-deferential artery expressed high levels of PDE5, similar to corpora cavernosa, immunolocalized in the endothelial and smooth muscle layer. In these arteries, tadalafil inhibited cyclic guanosine monophosphate breakdown (half maximal inhibitory concentration (IC50) in the low nanomolar range, as in corpora cavernosa) and increased the relaxant response to sodium nitroprusside. SHR prostate resulted markedly hypoxic (hypoxyprobe immunopositivity) and positive for HIF-1α and ETB, while tadalafil treatment restored oxygenation to WKY level at each time point. The mRNA expression of the HIF-1α target gene, BCL2/adenovirus E1B 19 kDa interacting protein 3, was significantly increased in SHR prostate and partially restored to WKY level by tadalafil.

Conclusion

Human vesicular-deferential artery is characterized by a high expression and activity of PDE5, which was inhibited by tadalafil in vitro. In SHR, tadalafil increases prostate tissue oxygenation, thus suggesting a possible mechanism through which PDE5i exert beneficial effects on LUT symptoms.
THE USE OF CFD TO IMPROVE THE PERFORMANCE OF A PARTIALLY LOADED COLD STORE
Authors: TANAKA FUMIHIKO , KONISHI YOSHIHIRO , KUROKI YUZURU , HAMANAKA DAISUKE , UCHINO TOSHITAKA
Published: August 2011

A transient three‐dimensional computational fluid dynamics model was developed to investigate the cooling performance of a partially loaded cold store in cooling process. The model accounted for turbulence by means of the standard k‐ε model with standard wall profiles. The model was validated successfully in cooling experiments with a mean error of 0.36 m/s and 1.4C for the air velocity in a refrigerated room and the temperature of the product, respectively. Based on the model, we studied the effect of different loading patterns of corrugated fiberboard containers filled with products in a cold store on cooling effectiveness. As a result, flat loading with air gaps was the optimal configuration to achieve high uniformity of temperature and rapid cooling. The findings of this study can help to elucidate and improve the cooling performance of refrigerated rooms for storing agricultural products.

PRACTICAL APPLICATIONS

The developed model is used to assess the cooling performance of partially loaded store. In this study, we have investigated how to stack the product in cold store to achieve uniform and rapid cooling. In order to extend the shelf life of fresh produce, it is very important to investigate the effect of loaded pattern on the cooling performance. The developed cooling model with 48 loaded corrugated fiberboard containers was based on one container cooling model. The approach presented in this paper can be used to design the loading pattern of agricultural products in a cold store.
FLOW AND FUNCTIONAL CHARACTERIZATION OF CORNSTARCH POWDER IN THE PRESENCE OF WATER AND PREGELATINIZED STARCH
Authors: DHANALAKSHMI K. , BHATTACHARYA SUVENDU
Published: August 2011

A model system comprising cornstarch has been agglomerated in the presence of binders like water and pregelatinized starch (PGS). Moisture and PGS contents have been varied between 12.3 and 20.1% and 0 and 6%, respectively. The physical characteristics of powder that have been determined include loose bulk density, wetting time and sinking time. A powder flow analyzer has been employed to determine flow characteristics like maximum force and energy for compression and decompression. An increase in moisture content and/or PGS increases average particle size and loose bulk density of agglomerates. The wet agglomerates show improved wetting and sinking times compared to dried agglomerates. Like wetting time, sinking time also decreases with an increase in moisture content meaning that these two indices behave in a similar manner. The functional properties like wetting and sinking times of powders at 18.5% moisture made with PGS are instant and only take less than 5 s.

PRACTICAL APPLICATION

Processed powdered foods frequently undergo the process of rehydration with a solvent system such as water or milk. Hence, the powder needs to be wetted quickly and thoroughly, sinking into the liquid rather than floating at the liquid surface and disperse/dissolve preferably without any lump formation. The importance of wetting time lies in the development and quality control of several food powders like milk powder, instant tea, coffee and mixes that are claimed to have instant properties. The generated data and findings, although developed on a model system, can be extrapolated to other food systems for developing new products for convenience to consumers.