bluuebunny/crossref_metadata_2025 huggingface dataset:
Methods for calculating the absolute entropy and free energy of biological systems based on ideas from polymer physics
Authors: Meirovitch Hagai
Published: July 2009

The commonly used simulation techniques, Metropolis Monte Carlo (MC) and molecular dynamics (MD) are of a dynamical type which enables one to sample system configurations i correctly with the Boltzmann probability, P, while the value of P is not provided directly; therefore, it is difficult to obtain the absolute entropy, S ∼ −ln P, and the Helmholtz free energy, F. With a different simulation approach developed in polymer physics, a chain is grown step‐by‐step with transition probabilities (TPs), and thus their product is the value of the construction probability; therefore, the entropy is known. Because all exact simulation methods are equivalent, i.e. they lead to the same averages and fluctuations of physical properties, one can treat an MC or MD sample as if its members have rather been generated step‐by‐step. Thus, each configuration i of the sample can be reconstructed (from nothing) by calculating the TPs with which it could have been constructed. This idea applies also to bulk systems such as fluids or magnets. This approach has led earlier to the “local states” (LS) and the “hypothetical scanning” (HS) methods, which are approximate in nature. A recent development is the hypothetical scanning Monte Carlo (HSMC) (or molecular dynamics, HSMD) method which is based on stochastic TPs where all interactions are taken into account. In this respect, HSMC(D) can be viewed as exact and the only approximation involved is due to insufficient MC(MD) sampling for calculating the TPs. The validity of HSMC has been established by applying it first to liquid argon, TIP3P water, self‐avoiding walks (SAW), and polyglycine models, where the results for F were found to agree with those obtained by other methods. Subsequently, HSMD was applied to mobile loops of the enzymes porcine pancreatic α‐amylase and acetylcholineesterase in explicit water, where the difference in F between the bound and free states of the loop was calculated. Currently, HSMD is being extended for calculating the absolute and relative free energies of ligand–enzyme binding. We describe the whole approach and discuss future directions. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis, molecular structure, IR and Raman spectra as well as DFT chemical calculations for alkylamides of thiocyanoacetic acid
Authors: Kucharska E. , Lorenc J. , Sa̧siadek W. , Ban‐Oganowska H. , Talik Z. , Hanuza J. , Ma̧czka M.
Published: July 2009

This paper reports on room‐temperature infrared (IR) and Raman studies and vibrational characteristics of amide and thiocyano groups of R‐NH‐CO‐CH2‐SCN n‐alkylamides of thiocyanoacetic acid (R = C8H17, C9H19, C12H25 and C14H29). Their molecular structure has been proposed on the basis of optimization process. The experimental wavenumbers have been compared to those obtained from discrete Fourier transform (DFT) quantum chemical calculations performed with the use of B3LYP/6–31G(d,p) approximation. The role of the hydrogen bonds in the stabilization of the structure has been analyzed. It was found that the hydrogen bonding and strong dynamic interactions between the unit cell components are responsible for the deviation of several theoretical wavenumbers from the experimental ones. Copyright © 2009 John Wiley & Sons, Ltd.
Optimising tip‐enhanced optical microscopy
Authors: Downes Andrew , Mouras Rabah , Mari Meropi , Elfick Alistair
Published: July 2009

We discuss the range of tip‐enhanced optical microscopies—namely mapping scattered light, fluorescence, Raman and coherent anti‐Stokes Raman scattering (CARS) signals on the scale of 10–20 nm. Through the use of measurements and finite‐element simulations, we explain what the optimum tip materials and sizes are and illumination wavelengths to use for all these modes of imaging. We also show that the observed limit of 50–100 µW of illumination power is due to a temperature rise of tens of degrees beneath the tip apex, and is most likely linked to the evaporation of water from the tip apex region. This has two important implications—that the tip is surrounded by water even when imaging ‘in air’, and that the tip and sample are both heated when imaging. With emphasis on Raman and CARS, we discuss how both these types of tip‐enhanced optical microscopy can be made about as fast as their diffraction‐limited counterparts. Copyright © 2009 Her Majesty the Queen in right of Canada. Published by John Wiley & Sons. Ltd.
The minor salivary gland biopsy as a diagnostic tool for Sjogren syndrome
Authors: Bamba Ravinder , Sweiss Nadera J. , Langerman Alexander J. , Taxy Jerome B. , Blair Elizabeth A.
Published: July 2009

Objectives/Hypothesis:

In suspected cases of Sjogren syndome (SS), patients are often referred for a labial minor salivary gland biopsy. However, studies have shown this test to be unreliable. Pathologic misinterpretation and immunosuppressive medications may affect the results of the biopsy. As a result, it is best to perform this procedure only when necessary. The purpose of the current study was to review clinical signs and symptoms of patients who underwent a lip biopsy to determine which patients benefited most from this procedure.

Study Design:

Retrospective review.

Methods:

A retrospective chart review of patients referred to otolaryngology for a lip biopsy for the diagnosis of SS.

Results:

Joint pain, salivary gland swelling, and abnormal serology (anti‐Sjogren syndrome A/anti‐Sjogren syndrome B) were more prevalent in the positive lip biopsy group (grade = 3 or 4). Out of the 12 patients who had both sicca symptoms and positive serology, nine (75%) had a grade = 4. Presence of sicca symptoms and positive serology were predictive of a positive biopsy (P = .017). Excluding those patients who were on immunosuppression for more than 6 weeks prior to the biopsy, the correlation became stronger (P = .011).

Conclusions:

In this study, clinical presentation of sicca symptoms and positive serology reliably predicted the results of a lip biopsy. The results of this study suggest that patients with clear criterion for SS may not require a lip biopsy, especially those patients on immunosuppression. When physicians suspect SS, a thorough clinical and laboratory examination is necessary to determine if a patient will benefit from a minor salivary gland biopsy. Laryngoscope, 2009
Cochlear nerve diameter in normal hearing ears using high‐resolution magnetic resonance imaging
Authors: Jaryszak Eric M. , Patel Nimish A. , Camp Morgan , Mancuso Anthony A. , Antonelli Patrick J.
Published: July 2009

Objectives:

Deficient cochlear nerves (CN) have been associated with poor cochlear implant performance. Normative data on CN diameter based on radiographic imaging have not been published. The objectives of this study were to determine if CN diameter could be reproducibly measured on parasagittal constructive interference in steady state (CISS)‐sequence magnetic resonance imaging (MRI) and to establish a normative range for CN diameter.

Study Design:

Retrospective review of MRI images by two independent blinded observers.

Methods:

Thirty patients (45 ears) with a CISS‐sequence MRI done for auditory complaints in patients with normal hearing in one ear were included. CN diameters were measured in a parasagittal plane just medial to the internal auditory canal (IAC) fundus by two independent observers. Cross‐sectional areas were calculated and interobserver agreement was evaluated.

Results:

The CN was identified in 100% of studied ears. In 93%, the diameters were able to be measured by both observers. In 7% of ears, the cochlear nerve was unable to be measured secondary to the proximity of the CN to IAC wall. The CN vertical diameter (1.4 mm ± 0.21 mm), horizontal diameter (1.0 mm ± 0.15 mm), and cross‐sectional area (1.1 mm ± 0.26 mm2) were normally distributed. There was good interobserver correlation for each measure.

Conclusions:

CN diameter can be reliably measured at the IAC fundus. This study establishes normative radiographic data for the CN diameter. These data may be used to evaluate the cause and treatment prognosis in patients with sensorineural hearing loss. Laryngoscope, 2009
Acellular dermis compared to skin grafts in oral cavity reconstruction
Authors: Girod Douglas A. , Sykes Kevin , Jorgensen Jeffery , Tawfik Ossama , Tsue Terance
Published: July 2009

Objectives/Hypothesis:

To compare the efficacy of acellular dermal matrix (ADM) and split thickness skin grafts (STSG) in oral cavity reconstruction.

Study Design:

Prospective cohort study.

Methods:

Thirty‐four patients were included in this study (ADM, n = 22; STSG, n = 12). Evaluation for patient demographics, graft site, graft contracture, and functional status as defined by the EORTC QLQ‐C30 and the H&N35 questionnaires. A subgroup of patients underwent graft site biopsy for histological analysis. A cost estimate of both procedures was also performed.

Results:

Patient groups were similar in age, sex, race, smoking exposure, and site grafted. More patients were treated with radiation therapy (pre‐ or postoperative) in the ADM group (45%) compared to the STSG group (17%). Graft failure rate was higher in the ADM group (14% vs. 0%), and both groups had similar estimated graft contraction. The quality of life survey results favored the ADM group, but only the category of trouble with social eating was statistically significant (P= .03). Radiation therapy had a significantly negative impact for both ADM and STSG. Histology demonstrated increased inflammation, fibrosis, and elastic fibers in the STSG group. The cost of the STSG was 3.5 times higher than the ADM group.

Conclusions:

Acellular dermis grafting for reconstruction of the oral cavity offers several advantages over STSG, including the lack of donor site morbidity, lower cost, a natural appearing mucosal surface, and comparable if not superior functional status. Lower graft survival rates for ADM in the setting of prior radiation and with thicker graft material was encountered. Laryngoscope, 2009
A model for 532‐nanometer pulsed potassium titanyl phosphate (KTP) laser—Induced injury in the rat larynx
Authors: Mallur Pavan S. , Amin Milan R. , Saltman Benjamin E. , Branski Ryan C.
Published: July 2009

Objectives/Hypothesis:

The potassium titanyl phosphate (KTP) laser is emerging as a potentially effective treatment for various vocal fold pathologies. To date, the precise mechanism(s) of action of this wavelength on the layered microarchitecture of the vocal fold remains unknown. The purpose of this study is to develop an in vivo model for the use of the KTP laser in the rat vocal fold and to characterize the potential of this model for future studies.

Study Design:

In vivo survival surgery.

Methods:

A model for videoendoscopic visualization and injury to the rat vocal fold was established using a microlaryngoscope and rigid telescope. Unilateral vocal fold injury was induced with the KTP laser at 10 Watts (W) 20 milliseconds (ms) pulse width. Animals were euthanized at 1 day post‐treatment. Larynges were subjected to gross visual analysis and histological analyses via hematoxylin and eosin and trichrome staining.

Results:

Consistent endoscopic visualization and injury was obtained without significant operative morbidity or mortality. The KTP laser caused superficial blanching and minor edema in the vocal fold, which resolved grossly by 24 hours postinjury. A modest inflammatory cell infiltrate was observed 1 day following injury. However, no remarkable alterations to the vocal fold microarchitecture were observed in the acute period.

Conclusions:

We propose that this novel model simulates the clinical scenario of laser use for the vocal folds. Use of this model will allow us to further characterize effects, mechanisms, and therapeutic efficacy of this wavelength. Laryngoscope, 2009
Secondary central compartment surgery for thyroid cancer
Authors: Ondik Michael P. , Dezfoli Seper , Lipinski Lindsay , Ruggiero Francis , Goldenberg David
Published: July 2009

Objectives/Hypothesis:

To report surgical outcomes in a large series of patients with a history of thyroid cancer who underwent secondary central compartment surgery (SCCS).

Study Design:

Retrospective chart review.

Methods:

The records of 44 patients who underwent 47 secondary central compartment surgeries for thyroid cancer were reviewed.

Results:

Metastatic nodal disease was found in 59.6% (28) central neck compartments. Remnant thyroid tissue was removed from 17 necks. The rate of transient and permanent vocal cord paralysis per SCCS was 2.1% and 6.4%, respectively. Transient and permanent hypoparathyroidism occurred in 11.9% and 9.5% of cases, respectively.

Conclusions:

SCCS is feasible but does carry some risk. The long‐term implications of early intervention in this setting are still largely unknown and will warrant future research. Laryngoscope, 2009
Effect of vegetation restoration on ant nest‐building activities following mobile dune stabilization in the Horqin Sandy land, Northern China
Authors: Liu R. T. , Zhao H. L. , Zhao X. Y.
Published: July 2009

Measurements of the density and characteristics (size and height) of ant mounds were carried out on mobile, semi‐mobile, semi‐fixed and fixed dunes in the Horqin Sandy Land, Northern China. The relationships between the distribution of ant mounds and the plant community (abundance and cover) were investigated, for areas within and across the dune stages. Changes in spatial pattern of ant mounds were also analysed following mobile dune stabilization. The results showed no ant mounds on mobile dunes; the mound density was significantly higher on fixed dunes than on semi‐fixed or semi‐mobile dunes. The mound density depended on plant density and cover across all dune stages, but not within any dune stage. The mound diameter increased but the mound height decreased from semi‐mobile dunes to fixed dunes. However, the mound diameter and height were not related to plant cover and density within any stabilization stage or across all dune stages. The spatial pattern of ant mounds tended to change from more clumped (semi‐mobile and semi‐fixed dunes) to less clumped and approached a random pattern (fixed dunes) along the dune stabilization gradient, which was related to the changing vegetation pattern during succession. Although the quantification of the number of ant species present was not attempted on each dune, the observed differences in ant colour and size suggest at least eight species were present. Fixed dunes were more attractive for different kinds of ant species, but the mound distribution exhibited a more random pattern with more continuous vegetation. Thus, different environmental conditions, especially in terms of the plant communities present at different dune stages, affected the activities and behaviour of the ants (including the distribution of mounds), but did not affect mound size and height. Copyright © 2009 John Wiley & Sons, Ltd.
Molecular complexes between π‐excedent heterocycles (indoles and carbazole) and π‐deficient polynitrobenzenes
Authors: López Concepción , Claramunt Rosa M. , Pinilla Elena , Torres M. Rosario , Alkorta Ibon , Elguero José
Published: July 2009

Five charge‐transfer complexes 1–5 derived from indoles (including a carbazole) and halogenopolynitrobenzenes (ClDNB, FDNB, ClTNB) as well as their individual components have been studied in the solid state by 13C CPMAS NMR. The stacking effects on the 13C chemical shifts have been rationalized by means of M05‐2X functional and GIAO/B3LYP/6‐311 ++G(d,p) calculations. The results, although only semiquantitative, are very promising for studying such structures. Copyright © 2009 John Wiley & Sons, Ltd.
Patient with amyloidoma of the ulnar nerve and salivary glands
Authors: Salameh Johnny , Baran Johanna L. , Tick Chong Peter Siao
Published: July 2009

Amyloidomas of the peripheral nervous system have been reported rarely. We describe a patient with a history of localized amyloidosis of the salivary glands who presented a few years later with paresthesias of her left medial arm, forearm, and fifth digit. A mass affecting the left ulnar nerve was confirmed by MRI studies. It was excised and proven on pathological examination to be an amyloidoma. The benign course of this patient's illness is consistent with localized amyloidosis affecting two different organs. Muscle Nerve, 2009
Optimal routing with failure‐independent path protection
Authors: Stidsen Thomas , Petersen Bjørn , Spoorendonk Simon , Zachariasen Martin , Rasmussen Kasper Bonne
Published: July 2009

Reliable communication has become crucial in today's information society. Modern communication networks are required to deliver reliable communication to their customers. Unfortunately, protection against network failures significantly hampers efficient utilization of network investments, because the associated routing problems become much harder. In this article we present a rigorous mathematical analysis of one of the most promising protection methods: Failure independent path protection. We present an LP model which is solved by column generation. The subproblem is proven to be strongly$ \cal N $P‐hard, but still solvable for medium sized networks through the use of specialized dynamic programming algorithms. This enables us to evaluate the performance of failure independent path protection for eight networks with up to 37 nodes and 57 links. The results indicate that only between 3% and 8% extra network capacity is necessary when compared with the capacity required by complete rerouting (which is the absolute lower bound for single link failure protection). © 2009 Wiley Periodicals, Inc. NETWORKS, 2010
Design of quadrature rules for Müntz and Müntz‐logarithmic polynomials using monomial transformation
Authors: Lombardi Guido
Published: July 2009

A method for constructing the exact quadratures for Müntz and Müntz‐logarithmic polynomials is presented. The algorithm does permit to anticipate the precision (machine precision) of the numerical integration of Müntz‐logarithmic polynomials in terms of the number of Gauss–Legendre (GL) quadrature samples and monomial transformation order. To investigate in depth the properties of classical GL quadrature, we present new optimal asymptotic estimates for the remainder. In boundary element integrals this quadrature rule can be applied to evaluate singular functions with end‐point singularity, singular kernel as well as smooth functions. The method is numerically stable, efficient, easy to be implemented. The rule has been fully tested and several numerical examples are included. The proposed quadrature method is more efficient in run‐time evaluation than the existing methods for Müntz polynomials. Copyright © 2009 John Wiley & Sons, Ltd.
Strict and effective bounds in goal‐oriented error estimation applied to fracture mechanics problems solved with XFEM
Authors: Panetier J. , Ladevèze P. , Chamoin L.
Published: July 2009

In this work, we analyze a method that leads to strict and high‐quality local error bounds in the context of fracture mechanics. We investigate in particular the capability of this method to evaluate the discretization error for quantities of interest computed using the extended finite element method (XFEM). The goal‐oriented error estimation method we are focusing on uses the concept of constitutive relation error along with classical extraction techniques. The main innovation in this paper resides in the methodology employed to construct admissible fields in the XFEM framework, which involves enrichments with singular and level set basis functions. We show that this construction can be performed through a generalization of the classical procedure used for the standard finite element method. Thus, the resulting goal‐oriented error estimation method leads to relevant and very accurate information on quantities of interest that are specific to fracture mechanics, such as mixed‐mode stress intensity factors. The technical aspects and the effectiveness of the method are illustrated through two‐dimensional numerical examples. Copyright © 2009 John Wiley & Sons, Ltd.
An essentially non‐oscillatory semi‐Lagrangian method for tidal flow simulations
Authors: El‐Amrani Mofdi , Seaïd Mohammed
Published: July 2009

We develop an essentially non‐oscillatory semi‐Lagrangian method for solving two‐dimensional tidal flows. The governing equations are derived from the incompressible Navier–Stokes equations with assumptions of shallow water flows including bed frictions, eddy viscosity, wind shear stresses and Coriolis forces. The method employs the modified method of characteristics to discretize the convective term in a finite element framework. Limiters are incorporated in the method to reconstruct an essentially non‐oscillatory algorithm at minor additional cost. The central idea consists in combining linear and quadratic interpolation procedures using nodes of the finite element where departure points are localized. The resulting semi‐discretized system is then solved by an explicit Runge–Kutta Chebyshev scheme with extended stages. This scheme adds in a natural way a stabilizing stage to the conventional Runge–Kutta method using the Chebyshev polynomials. The proposed method is verified for the recirculation tidal flow in a channel with forward‐facing step. We also apply the method for simulation of tidal flows in the Strait of Gibraltar. In both test problems, the proposed method demonstrates its ability to handle the interaction between water free‐surface and bed frictions. Copyright © 2009 John Wiley & Sons, Ltd.
African American women's beliefs about mental illness, stigma, and preferred coping behaviors
Authors: Ward Earlise C. , Heidrich Susan M.
Published: July 2009

We examined African American women's representations/beliefs about mental illness, preferred coping behaviors if faced with mental illness, whether perceived stigma was associated with treatment‐seeking, and if so, whether it was related to beliefs and coping preference, and whether these variables differed by age group. Participants were 185 community‐dwelling African American women 25 to 85 years of age. Results indicated the women believed that mental illness is caused by several factors, including family‐related stress and social stress due to racism, is cyclical, and has serious consequences but can be controlled by treatment. Participants endorsed low perceptions of stigma. Major preferred coping strategies included praying and seeking medical and mental health care. Age differences were found in all variables except stigma. © 2009 Wiley Periodicals, Inc. Res Nurs Health 32:480–492, 2009
Fibril protein fragmentation pattern in systemic AL‐amyloidosis
Authors: Enqvist Stina , Sletten Knut , Westermark Per
Published: July 2009

Immunoglobulin light chain (AL)‐amyloidosis was one of the first types of amyloidosis discovered and still little is known about its pathogenic mechanisms. One major obstacle is the very heterogeneous condition; in fact, every patient could be considered to have their own disease since symptoms and outcome vary enormously. The reason for this is not known but intrinsic factors of the immunoglobulin light chain (LC) and the fact that every LC is unique seem to be important. Post‐translational modifications such as glycosylation and proteolysis are most certainly involved. By using western blotting, we studied in detail the proteolytic pattern in six patients with AL‐amyloidosis of kappa type with the aid of three peptide antisera against two domains in the constant segment and one conserved domain in framework 3 of the variable region. Materials from one to five organs were analysed. The result clearly demonstrates that the fragmentation pattern was similar in amyloid of different organs in one patient but differed greatly between patients. Full‐length, N‐, and C‐terminal fragments were detected with the three antisera. The results strongly support the hypothesis that proteolytic cleavage occurs after fibril formation. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Type 1 deiodinase activity and generation of triiodothyronine (T3) in prostate of sexually active rats
Authors: López‐Juárez Alejandra , Delgado Guadalupe , Aceves Carmen , Anguiano Brenda
Published: July 2009

BACKGROUND

Thyroxine (T4) and triiodothyronine (T3) are involved in the development and function of the male reproductive system. The type 1 deiodinase enzyme (D1) plays a major role in the intracellular conversion of T4 to the active form, T3. D1 is expressed in the prostate of pubescent rats, but it is unknown whether locally generated T3 is involved in the development and function of this gland.

METHODS

D1 activity was analyzed in prostates from neonatal to old rats. Local T3 generation (D1 and T3 levels) was evaluated in adult animals with 1–5 months of continuous sexual activity. D1 activity was measured by the radiolabeled‐iodide‐release method and T3 concentration by radioimmunoassay. Secretory activity of the prostate was evaluated by a morphological analysis of epithelium (hematoxilin‐eosin stain) and by measuring the activity of acid phosphatase as a marker enzyme for secretion.

RESULTS

The highest prostate D1 activity was expressed around puberty, and it was almost undetectable during the neonatal period and with aging. Interestingly, 1 and 4 months of sexual activity avoided the decrease of D1 activity associated with aging. Sexual activity provoked a hypertrophy and functional hyperplasia in all lobes, but D1 and acid phosphatase activity increased only in the ventral lobe. D1 activity correlated with an increase in the prostatic T3 concentration.

CONCLUSIONS

The increased local generation of T3 in prostate might be related to: (1) the differentiation/maturation that occurs at puberty and (2) the energy expenditure associated with maintaining the secretory activity of the glandular epithelium. Prostate 69: 1651–1659, 2009. © 2009 Wiley‐Liss, Inc.
Prescribing in 2008: savings made in four drug groups
Authors: Chaplin Steve
Published: July 2009

The NAO report Prescribing Savings in 2008 details the savings made by GPs through improved prescribing of four groups of drugs. Steve Chaplin analyses the findings. Copyright © 2009 Wiley Interface Ltd.
Electronic transport of silicon nanowires with surface defects
Authors: Li Junwen , Jayasekera Thushari , Meunier Vincent , Mintmire John W.
Published: July 2009

We report first‐principle results for the electronic transport properties of silicon nanowires along the 〈110〉 direction with hydroxyl surface defects. The Hamiltonian and overlap matrices of the system are obtained using an all‐electron, Gaussian‐basis, local‐density functional approach adapted for helical symmetry and the transport calculation makes use of the Landauer approach. We show that the hydroxyl defects can greatly reduce the conductance of hydrogen‐passivated Si nanowires and can be used to tune the conductance of the silicon nanowires. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Strong correlation effects in the electron binding energies of phthalocyanine
Authors: Zakrzewski Viatcheslav G. , Dolgounitcheva Olga , Ortiz J. V.
Published: July 2009

Vertical ionization energies of free‐base phthalocyanine are determined with the partial third‐order and the third‐order algebraic diagrammatic construction approximations of electron propagator theory. A triple‐ζ plus polarization basis set is used in calculations performed with semidirect algorithms. Strong correlation effects occur for all final states with π holes. Whereas the Koopmans description of the lowest cationic state retains some qualitative validity, this approximation collapses in the remaining π final states. The results are in good agreement with photoelectron spectra. Two vertical electron affinities correspond to bound 2B1g and 2B2g anionic states of phthalocyanine. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Spatial distribution of large wood jams in streams related to stream‐valley geomorphology and forest age in Northern Michigan
Authors: Morris Arthur E. L. , Goebel P. Charles , Palik Brian J.
Published: July 2009

Geomorphology at the scale of stream valleys influences smaller scale processes that give rise to spatially distributed patches, including large wood jams (LWJ) in streams. Understanding the spatial distribution of LWJ along streams with reference to large‐scale geomorphology is valuable for understanding stream and riparian interactions, and may be critical for effective stream management and restoration. We surveyed the locations of LWJ along 18 stream segments within study areas defined by stream‐valley geomorphology. The objective of this study was to test the prediction that LWJ in this system will be aggregated in areas defined by stream‐valley geomorphology, but be randomly distributed at smaller scales. The spatial distribution of LWJ was analysed by a one‐dimensionalK‐function analysis capable of detecting aggregated, random and segregated patterns at different scales. The prediction that LWJ aggregate in areas defined by stream‐valley geomorphology was supported: LWJ aggregated at scales up to several kilometres in three streams. LWJ also was segregated at smaller scales in two of these streams; this was detectable when several stream valley segments were considered together. The prediction that LWJ would be randomly distributed at smaller scales was supported at most smaller scales for most streams. In fact, 40% of individual stream valley segments contained LWJ that were randomly distributed at all scales. Twenty‐seven per cent of individual stream valley segments showed segregated LWJ distributions. Large‐scale aggregation of LWJ evidences the need to select reference reaches that encompass several geomorphic patches at the scale of the stream valley. Segregated patterns of LWJ distributions evidence opportunities to better understand the relationships between hydraulic systems, material transport dynamics and riparian forests. Copyright © 2009 John Wiley & Sons, Ltd.
Admission control and handover management for high‐speed trains in vehicular geostationary satellite networks with terrestrial gap‐filling
Authors: Lattanzi Fabio , Giambene Giovanni , Acar Guray , Evans Barry
Published: July 2009

Following a recent upgrade, the Digital Video Broadcasting—Return Channel Satellite (DVB‐RCS) standard sets up to support terminal mobility. In this scenario, integration with terrestrial systems becomes a primary concern to ensure network connectivity in urban areas. This article proposes an integrated satellite–terrestrial architecture for the provision of broadband services onboard high‐speed trains, in which terrestrial cellular networks are seen as viable gap‐fillers for discontinuous satellite coverage. We derive an analytical model of the hybrid DVB‐RCS‐cellular system by exploiting analogies between the mobility pattern predictability of LEO constellations and that of high‐speed trains. Terminals whose QoS cannot be guaranteed by the satellite segment are proposed to temporarily divert the connections towards the terrestrial infrastructure, where available. Using an iterative approach based on the Erlang fixed‐point approximation, we show performance improvements with respect to stand‐alone satellite systems in terms of handover failure probability and overall resource utilization. The analytical model is also validated via our ns2‐based DVB‐RCS packet‐level simulator. Detailed modelling of synchronization and signalling mechanisms confirms the accuracy of the analytical results, and shows that topology and mobility information can contribute to refine radio resource utilization optimality when used jointly. Copyright © 2009 John Wiley & Sons, Ltd.
Dynamics of concurrent software development
Authors: Rahmandad Hazhir , Weiss David M.
Published: July 2009

In a concurrent development process different releases of a software product overlap. Organizations involved in concurrent software development not only experience the dynamics common to single projects, but also face interactions between different releases of their product: they share resources among different stages of different projects, including customer support, they have a common code base and architecture that carries problems across releases, they use the same capabilities, and their market success in early releases impacts their resources in later ones. Drawing on two case studies we discuss some of the feedback processes central to concurrent software development and build a simple simulation model to analyze the resulting dynamics. This model sheds light on tipping dynamics, the nature of inter‐project feedback loops, and alternative resource allocation policies relevant to management of concurrent software development. Copyright © 2009 John Wiley & Sons, Ltd.
The Neurotransmitter VIP Expands the Pool of Symmetrically Dividing Postnatal Dentate Gyrus Precursors via VPAC2 Receptors or Directs Them Toward a Neuronal Fate via VPAC1 receptors
Authors: Zaben Malik , John Sheward W. , Shtaya Anan , Abbosh Christopher , Harmar Anthony J. , Pringle Ashley K. , Gray William P.
Published: July 2009

The controlled production of neurons in the postnatal dentate gyrus and thoughout life is important for hippocampal learning and memory. The mechanisms underlying the necessary coupling of neuronal activity to neural stem/progenitor cell (NSPC) function remain poorly understood. Within the dentate subgranular stem cell niche, local interneurons appear to play an important part in this excitation-neurogenesis coupling via GABAergic transmission, which promotes neuronal differentiation and integration. Here we show that vasoactive intestinal polypeptide, a neuropeptide coreleased with GABA under specific firing conditions, is uniquely trophic for proliferating postnatal nestin-positive dentate NSPCs, mediated via the VPAC2 receptor. We also show that VPAC2 receptor activation shifts the fate of symmetrically dividing NSPCs toward a nestin-only phenotype, independent of the trophic effect. In contrast, selective VPAC1 receptor activation shifts NSPC fate toward granule cell neurogenesis without any trophism. We confirm a trophic role for VPAC2 receptors in vivo, showing reduced progeny survival and dentate neurogenesis in adult Vipr2−/− mice. We also show a specific reduction in type 2 nestin-positive precursors in vivo, consistent with a role for VPAC2 in maintaining this cell population. This work provides the first evidence of differential fate modulation of neurogenesis by neurotransmitter receptor subtypes and extends the fate-determining effects of neurotransmitters to maintaining the nestin-positive pool of NSPCs. This differential receptor effect may support the independent pharmacological manipulation of precursor pool expansion and neurogenic instruction for therapeutic application in the treatment of cognitive deficits associated with a decline in neurogenesis.
Direct Evidence of Mesenchymal Stem Cell Tropism for Tumor and Wounding Microenvironments Using In Vivo Bioluminescent Imaging
Authors: Kidd Shannon , Spaeth Erika , Dembinski Jennifer L. , Dietrich Martin , Watson Keri , Klopp Ann , Battula Venkata Lokesh , Weil Micheal , Andreeff Michael , Marini Frank C.
Published: July 2009

Multipotent mesenchymal stromal/stem cells (MSC) have shown potential clinical utility. However, previous assessments of MSC behavior in recipients have relied on visual detection in host tissue following sacrifice, failing to monitor in vivo MSC dispersion in a single animal and limiting the number of variables that can be observed concurrently. In this study, we used noninvasive, in vivo bioluminescent imaging to determine conditions under which MSC selectively engraft in sites of inflammation. MSC modified to express firefly luciferase (ffLuc-MSC) were injected into healthy mice or mice bearing inflammatory insults, and MSC localization was followed with bioluminescent imaging. The inflammatory insults investigated included cutaneous needle-stick and surgical incision wounds, as well as xenogeneic and syngeneic tumors. We also compared tumor models in which MSC were i.v. or i.p. delivered. Our results demonstrate that ffLuc-expressing human MSC (hMSC) systemically delivered to nontumor-bearing animals initially reside in the lungs, then egress to the liver and spleen, and decrease in signal over time. However, hMSC in wounded mice engraft and remain detectable only at injured sites. Similarly, in syngeneic and xenogeneic breast carcinoma-bearing mice, bioluminescent detection of systemically delivered MSC revealed persistent, specific colocalization with sites of tumor development. This pattern of tropism was also observed in an ovarian tumor model in which MSC were i.p. injected. In this study, we identified conditions under which MSC tropism and selective engraftment in sites of inflammation can be monitored by bioluminescent imaging over time. Importantly, these consistent findings were independent of tumor type, immunocompetence, and route of MSC delivery.
Reference ranges for middle cerebral artery peak systolic velocity in monochorionic diamniotic twins: a longitudinal study
Authors: Klaritsch P. , Deprest J. , Van Mieghem T. , Gucciardo L. , Doné E. , Jani J. , Lewi P. , Rasmussen S. , Lewi L.
Published: July 2009

Objectives

The role of middle cerebral artery (MCA) peak systolic velocity (PSV) has become established in the management of fetal anemia. To date, singleton reference ranges have also been used in twin pregnancies. However, in monochorionic twin pregnancies, normal ranges for cerebral blood flow may differ from those in singletons owing to intertwin blood exchange. We aimed to establish gestational age‐specific reference ranges for MCA‐PSV in monochorionic diamniotic (MCDA) twin pregnancies, to compare them with previously reported singleton reference ranges, and to establish terms for calculating conditional reference intervals appropriate for individual serial measurements.

Methods

In a prospective longitudinal study we examined 50 uncomplicated MCDA pregnancies that were recruited between 11 and 14 weeks of gestation. Fetal MCA Doppler waveforms were assessed biweekly from 15 weeks of gestation onwards. Multilevel modeling was used to estimate gestational age‐specific reference ranges for MCA‐PSV and terms for conditional reference intervals were established.

Results

Based on 824 observations in 100 fetuses, normative ranges from 15 to 37 weeks of gestation were constructed. Median MCA‐PSV increased with advancing gestational age. Measurements between 18 and 37 weeks were comparable to those in singletons. However, before 18 weeks MCA‐PSV values were higher in MCDA twin pregnancies compared with singleton references.

Conclusions

Between 18 and 37 weeks of gestation, reference ranges of singletons can be used to assess fetal anemia in MCDA twin pregnancies. Prior to 18 weeks the application of singleton references may lead to an increased number of false‐positive diagnoses of presumed fetal anemia in MCDA twin pregnancies. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Synthesis and Crystal Structure of Ca2Ag1.83Al0.67Ge1.50 – A Solid Solution with the NbCoB‐type structure
Authors: Ponou Siméon , Lidin Sven
Published: July 2009

The crystal structure of the new phase, Ca2Ag1.83Al0.67Ge1.50(1) (1) was determined by single‐crystal X‐ray diffraction, after the compound was obtained by high temperature synthesis technique. 1 crystallizes with the NbCoB type structure in the orthorhombic space group Pmmn (no. 59) with unit cell parameters: a = 20.505(1) Å, b = 4.3807(2) Å, c = 7.2211(3) Å, V = 648.65 Å3 (Z = 5). The structure of the title compound represent a rare intergrowth of the well known KHg2 (or CeCu2) and Fe2P type structures.
Ring‐shaped [(TiCl2)(1,3‐P2S8)]2 Molecules Containing Uncommon [P2S8]2– Anions
Authors: Hoppe Diana , Pfitzner Arno
Published: July 2009

Intensely red, moisture‐sensitive crystals of [(TiCl2)(1,3‐P2S8)]2 were obtained by the reaction of TiCl4 and P4S10 at room temperature. The crystal structure determination revealed molecules formally consisting of two units of the anion [1,3‐P2S8]2– connected with two [TiCl2]2+ cations resulting in the ring‐shaped [(TiCl2)(1,3‐P2S8)]2. The thiophosphate [1,3‐P2S8]2– forms a six‐membered ring and has a rather uncommon constitution among the multitude of anionic phosphorus sulfides and selenides.
Interaction of four parallel non‐symmetric permeable mode‐III cracks with different lengths in a functionally graded piezoelectric material plane
Authors: Zhang P.‐W. , Zhou Z.‐G. , Li G.
Published: July 2009

In this paper, the behavior of four parallel non‐symmetric permeable cracks with different lengths in a functionally graded piezoelectric material plane subjected to anti‐plane shear stress loading was studied by the Schmidt method. The problem was formulated through Fourier transform into four pairs of dual integral equations, in which unknown variables are the jumps of displacements across the crack surfaces. To solve the dual integral equations, the jumps of displacements across the crack surfaces were directly expanded as a series of Jacobi polynomials. The results show that the stress intensity factors at the crack tips depend on the lengths and spacing of cracks and the material parameters. It is also revealed that the crack shielding effect presents in functionally graded piezoelectric materials.
Evaluation of three immobilization combinations in the capybara (Hydrochoerus hydrochaeris)
Authors: King Jay D. , Congdon Elizabeth , Tosta Carolina
Published: July 2009

Capybaras (Hydrochoerus hydrochaeris) are the world's largest rodent. Owing to its uniqueness, 50 AZA institutions in North America display this species. As shown by a survey, no standard anesthetic protocol has been developed for this species. As a part of an ongoing behavioral study in Venezuela, capybaras were surgically implanted with radio transmitters. Animals were randomly assigned to one of the three immobilization protocols: (1) Tiletamine HCl/Zolazepam HCl, (2) Tiletamine HCl/Zolazepam HCl/Medetomidine HCl, and (3) Tiletamine HCl/Zolazepam HCl/Medetomidine HCl/Butorphanol tartrate. The protocol recommended for minimally invasive procedures when inhalant anesthetics are unavailable is a combination of Tiletamine HCl/Zolazepam HCl/Medetomidine HCl/Butorphanol tartrate. This is based on ease of administration, volume, onset of action, depth of anesthetic achieved, reversibility, safety, and costs. Zoo Biol 29:59–67, 2010. © 2009 Wiley‐Liss, Inc.
Systematic Video Game Training in Surgical Novices Improves Performance in Virtual Reality Endoscopic Surgical Simulators: A Prospective Randomized Study
Authors: Schlickum Marcus Kolga , Hedman Leif , Enochsson Lars , Kjellin Ann , Felländer‐Tsai Li
Published: July 2009

Background

Previous studies have shown a correlation between previous video game experience and performance in minimally invasive surgical simulators. The hypothesis is that systematic video game training with high visual‐spatial demands and visual similarity to endoscopy would show a transfer effect on performance in virtual reality endoscopic surgical simulation.

Methods

A prospective randomized study was performed. Thirty surgical novices were matched and randomized to five weeks of systematic video game training in either a first‐person shooter game (Half Life) with high visual‐spatial demands and visual similarities to endoscopy or a video game with mainly cognitive demands (Chessmaster). A matched control group (n = 10) performed no video game training during five weeks. Performance in two virtual reality endoscopic surgical simulators (MIST‐VR and GI Mentor II) was measured pre‐ and post‐training. Before simulator training we also controlled for students’ visual‐spatial ability, visual working memory, age, and previous video game experience.

Results

The group training with Half Life showed significant improvement in two GI Mentor II variables and the MIST‐VR task MD level medium. The group training with Chessmaster only showed an improvement in the MIST‐VR task. No effect was observed in the control group. As recently shown in other studies, current and previous video game experience was important for simulator performance.

Conclusions

Systematic video game training improved surgical performance in advanced virtual reality endoscopic simulators. The transfer effect increased when increasing visual similarity. The performance in intense, visual‐spatially challenging video games might be a predictive factor for the outcome in surgical simulation.
Surgical strategy of biliary papillomatosis in Western countries
Authors: Vibert Eric , Dokmak Safi , Belghiti Jacques
Published: July 2009

Surgical resection, considered the optimal treatment of biliary papillomatosis, often remains incomplete due to high risk of recurrence in view of positive margins or recurrence on the remnant bile duct because of its multifocality. Resection of the whole biliary tree by liver transplantation and duodenopancreatectomy can be regarded as the only curative treatment. However, this approach has resulted in unfavorable results in patients with advanced tumor invasion and/or positive lymph nodes. For the majority of biliary tumors, preoperative assessment is often insufficient. Therefore, we advocate initial partial resection as a first step to eliminate both advanced tumor invasion and/or positive lymph nodes on definitive analysis of the specimen. We propose the strategy of initial resection for selecting the patients who would actually benefit from liver transplantation.
The Acute Liver Injury in Mice Caused by Nano-Anatase TiO2
Authors: Ma Linglan , Zhao Jinfang , Wang Jue , Liu Jie , Duan Yanmei , Liu Huiting , Li Na , Yan Jingying , Ruan Jie , Wang Han , Hong Fashui
Published: July 2009

Although it is known that nano-TiO2or other nanoparticles can induce liver toxicities, the mechanisms and the molecular pathogenesis are still unclear. In this study, nano-anatase TiO2(5 nm) was injected into the abdominal cavity of ICR mice for consecutive 14 days, and the inflammatory responses of liver of mice was investigated. The results showed the obvious titanium accumulation in liver DNA, histopathological changes and hepatocytes apoptosis of mice liver, and the liver function damaged by higher doses nano-anatase TiO2. The real-time quantitative RT-PCR and ELISA analyses showed that nano-anatase TiO2can significantly alter the mRNA and protein expressions of several inflammatory cytokines, including nucleic factor-κB, macrophage migration inhibitory factor, tumor necrosis factor-α, interleukin-6, interleukin-1β, cross-reaction protein, interleukin-4, and interleukin-10. Our results also implied that the inflammatory responses and liver injury may be involved in nano-anatase TiO2-induced liver toxicity.
Stability Profile of Fatty Acids in Yak (Bos grunniens) Kidney Fat During the Initial Stages of Autoxidation
Authors: Zhang HaiRong , Wang Qiang , Fan Enguo
Published: July 2009

Previously, we have shown that the fatty acid composition of yak kidney is of reasonable value and is suitable for further development of possible commercial products. Changes in the fatty acids of yak kidney fat during the initial stages of storage have been investigated. The full period of autoxidation was determined by peroxide value (PV) and thiobarbituric acid‐reactive substances (TBARS) at 15 ± 1 °C for up to 70 days. The stability profile of the fatty acids identified by gas chromatography demonstrated that saturated fatty acids increased from 49.68 to 55.96% and that polyunsaturated fatty acids and monounsaturated fatty acids decreased from 10.73 to 6.95% and from 37.85 to 28.22%, respectively. Amounts of all the functional fatty acids except conjugated linoleic acid and linoleic acid, started to decrease after 10 days of storage. These results indicated that the initial stage of autoxidation occurred during the first 25 days of storage. It is suggested that development of potential commercial products should be accomplished within ten days, because the functional fatty acids started to decrease after this period of storage. In addition, the good correlation between PV/TBARS values and changes of individual fatty acids could be used as an indicator to monitor the changes of the functional fatty acid during the development process of yak kidney fat‐related commercial products.