bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Modal Coupling on the Nonlinear Dynamics of Augusti’s Model
Authors: Orlando Diego , Gonçalves Paulo B. , Rega Giuseppe , Lenci Stefano
Published: June 2011

The nonlinear behavior and stability under static and dynamic loads of an inverted spatial pendulum with rotational springs in two perpendicular planes, called Augusti’s model, is analyzed in this paper. This 2DOF lumped-parameter system is an archetypal model of modal interaction in stability theory representing a large class of structural problems. When the system displays coincident buckling loads, several post-buckling paths emerge from the bifurcation point (critical load) along the fundamental path. This leads to a complex potential energy surface. Herein, we aim to investigate the influence of nonlinear modal interactions on the dynamic behavior of Augusti’s model. Coupled/uncoupled dynamic responses, bifurcations, escape from the pre-buckling potential well, stability, and space-time-varying displacements; attractor-manifold-basin phase portraits are numerically evaluated with the aim of enlightening the system complex response. The investigation of basins evolution due to variation of system parameters leads to the determination of erosion profiles and integrity measures which enlighten the loss of safety of the structure due to penetration of eroding fractal tongues into the safe basin.
Multi-Objective Robust Optimization Under Interval Uncertainty Using Online Approximation and Constraint Cuts
Authors: Hu W. , Li M. , Azarm S. , Almansoori A.
Published: June 2011

Many engineering optimization problems are multi-objective, constrained and have uncertainty in their inputs. For such problems it is desirable to obtain solutions that are multi-objectively optimum and robust. A robust solution is one that as a result of input uncertainty has variations in its objective and constraint functions which are within an acceptable range. This paper presents a new approximation-assisted MORO (AA-MORO) technique with interval uncertainty. The technique is a significant improvement, in terms of computational effort, over previously reported MORO techniques. AA-MORO includes an upper-level problem that solves a multi-objective optimization problem whose feasible domain is iteratively restricted by constraint cuts determined by a lower-level optimization problem. AA-MORO also includes an online approximation wherein optimal solutions from the upper- and lower-level optimization problems are used to iteratively improve an approximation to the objective and constraint functions. Several examples are used to test the proposed technique. The test results show that the proposed AA-MORO reasonably approximates solutions obtained from previous MORO approaches while its computational effort, in terms of the number of function calls, is significantly reduced compared to the previous approaches.
Pressure Drop in Generating Free-Surface Liquid Microjet Array From Short Cylindrical Orifices
Authors: Bhunia Avijit , Chen C. L.
Published: June 2011

Liquid microjet arrays have received a lot of research attention in recent years due to its high heat flux cooling capability. The microjets are generated from a jet head cavity with a liquid inlet port on one wall and an array of micro-orifices on another wall. An important, yet relatively less studied aspect of the topic is the pressure (also frequently referred to as the pressure drop) necessary to generate the jets and maintain certain jet velocity. In this study we investigate the pressure drop for17 different array patterns of liquid jet issuing in a surrounding gas (air) medium, i.e., a free surface liquid jet. The number of jets varies from 1 to 126, while the jet diameter ranges from 99 to 208 μm. The current results show more than 200% deviation from the existing correlations in the literature. Through a systematic experimental study we identify the functional dependence of pressure drop on the various geometric parameters. The results uncover the reasons behind the widespread disagreement between the current data and the existing correlations. Pressure drop shows a weak, nonlinear dependence on the orifice wall thickness, compared to the linear dependence used in the existing correlations. Furthermore, the depth of the jet head cavity is shown to be an important parameter dictating pressure drop, unlike the previous studies that inherently assume the cavity to be an infinite reservoir. A new dimensionless pressure drop parameter is proposed and its variation with the jet Reynolds number is correlated. The new correlation predicts all the experimental data within a ± 10% range.
Straight-Build Assembly Optimization: A Method to Minimize Stage-by-Stage Eccentricity Error in the Assembly of Axisymmetric Rigid Components (Two-Dimensional Case Study)
Authors: Hussain T. , Yang Z. , Popov A. A. , McWilliam S.
Published: June 2011

For assembly of rotating machines, such as machining tools, industrial turbomachinery, or aircraft gas turbine engines, parts need to be assembled in order to avoid internal bending of the geometric axis of the rotor to meet functional and vibration requirements. Straight-build assembly optimization is a way of joining parts together in order to have a straight line between the centers of the components. Straight-build assembly is achieved by minimizing eccentricity error stage-by-stage in the assembly. To achieve minimal eccentricity, this paper proposes three assembly procedures: (i) table-axis-build assembly by minimizing the distances from the centers of components to table axis; (ii) minimization of the position error between actual and nominal centers of the component; and (iii) central-axis-build assembly by minimizing the distances from the centers of components to a central axis. To test the assembly procedures, two typical assembly examples are considered using four identical rectangular components and four nonidentical rectangular components, respectively. Monte Carlo simulations are used to analyze the tolerance build-up, based on normally distributed random variables. The results show that assembly variations can be reduced significantly by selecting best relative orientation between mating parts. The results also show that procedures (i) and (ii) have the most potential to minimize the error build-up in the straight build of an assembly. For these procedures, the variation is reduced by 45% and 40% for identical and nonidentical components, respectively, compared to direct-build assembly. Procedure (iii) provides better performance than direct-build assembly for identical components assembly, while it gives smaller variation at the first two stages and larger variation at the third stage for nonidentical components assembly. This procedure could be used in an assembly with limited stages.
Deep UV patterning of 3-amino-propyl-triethoxy-silane self-assembled molecular layers on alumina
Authors: Samantaray C. B. , Hastings Jeffrey. T.
Published: June 2011

Organosilane molecular layers are widely used to modify surface functionality and for the immobilization and assembly of more complex nanostructures. Unlike alkanethiol layers, simple organosilanes have not been directly photopatterened with easily accessible optical wavelengths. In particular, 3-amino-propyl-triethoxy-silane (APTES) is commonly used for such purposes, and a direct means of patterning molecular layers of APTES would be of interest for a variety of applications. However, previous efforts to photopattern aminosilanes have been limited to vacuum ultraviolet (VUV) radiation at 172 nm. Here APTES layers were photopatterned on partially oxidized aluminum using 266 nm laser irradiation. APTES layers were grown on both oxidized Al and Si surfaces for patterning and reflection absorption infrared spectroscopy purposes. APTES on aluminum oxide, in contrast to silicon, retains ethoxy groups. These groups are eliminated by 266 nm laser irradiation providing insight into the photopatterning mechanism. Unlike 172 nm irradiation, the 266 nm wavelength retains the APTES backbone. Microscale patterning of APTES has been performed and the exposed samples were processed in a second organosilane, n-butyltrichlorosilane (BTS) or n-octadecyltrimethoxysilane (ODS), that enhances secondary-electron contrast compared to a patterned APTES sample. The authors found that BTS/APTES patterns exhibited contrast reversal compared to ODS/APTES structures. Direct patterning of organosilane films using deep-UV (rather than VUV or e-beam) exposure allows the use of coherent and continuous-wave sources and also prevents exposure of underlying resist layers when using the organosilane pattern as an in situ metrology standard for electron-beam lithography.
Cryogenic shallow reactive ion etch process for profile control on silicon on insulator platform
Authors: Bakhtazad Aref , Huo Xuan , Sabarinathan Jayshri
Published: June 2011

A cryogenic reactive ion etch (RIE) process is presented to fabricate shallow two-dimensional photonic crystal type dense pattern microstructures (usually with thickness less than 500 nm and with low aspect ratios ∼1–4) on a silicon on insulator (SOI) platform. Deep RIE etching of silicon has been previously investigated particularly with respect to etch rate, etch profile, and selectivity. While using an oxide layer as an etch stop has also been investigated, the profile control near the oxide interface is usually not very important due to the large aspect ratios. However, for shallow structures with low aspect ratios, profile control near the oxide interface is important while the etch rate and the selectivity are not as much of a concern. The authors show how the presence of an insulating layer close to the silicon etch surface makes the cryogenic etch process different from that of bulk silicon in many respects. Under these circumstances, the effects of various etch process parameters, including O2 flow, capacitively coupled rf power, substrate temperature, and chamber pressure on the etch profile quality were studied systematically on the SOI platform. The results are contrasted with bulk silicon cryogenic etching.
Science Signaling
Podcast: 14 June 2011
Authors: Treisman Richard , McDonald Neil Q. , Mouilleron Stéphane , VanHook Annalisa M.
Published: June 2011

Structural analysis reveals how increasing concentrations of monomeric actin prevent a transcriptional coactivator from promoting expression of target genes.
Stressing Bacteria to Death
Authors: Gough Nancy R.
Published: June 2011

The bactericidal activity of mammalian peptidoglycan recognition proteins involves activation of a bacterial two-component stress defense pathway.
mTOR Substrates Revealed
Authors: Ray L. Bryan
Published: June 2011

A search for substrates of a growth-promoting kinase revealed a regulatory feedback loop involved in tumor suppression.
Smoking and Body Weight
Authors: Stern Peter R.
Published: June 2011

Nicotine decreases weight gain by targeting a brain pathway involved in the regulation of energy balance and food intake.
Seeing the Heat
Authors: Vinson Valda K.
Published: June 2011

Thermal activation of visual pigments involves the same chromophore-isomerization reaction as does light activation.
Steady-State Pharmacokinetics of Tenofovir-Based Regimens in HIV-Infected Pediatric Patients
Authors: King Jennifer R. , Yogev Ram , Jean-Philippe Patrick , Graham Bobbie , Wiznia Andrew , Britto Paula , Carey Vincent , Hazra Rohan , Acosta Edward P. ,   for the P1058 Protocol Team
Published: June 2011

HIV-infected children are treated with tenofovir in combination with other, potentially interacting, antiretroviral agents. We report the pharmacokinetic parameters of tenofovir in combination with efavirenz, darunavir-ritonavir, or atazanavir-ritonavir in HIV-infected children. HIV-infected patients 8 to 18 years of age receiving a tenofovir (300 mg)-based regimen containing efavirenz (300 or 600 mg) once daily (group 1), darunavir (300 or 600 mg)-ritonavir (100 mg) twice daily (group 2), or atazanavir (150 to 400 mg)-ritonavir (100 mg) once daily (group 3) were enrolled. Plasma samples were collected over a 24-h time interval. The 90% confidence intervals (90% CI) of the geometric means for the area under the plasma concentration-time curve (AUC) and the minimum concentration of drug in serum (
C
min
) of each antiretroviral were computed and checked for overlap with intervals bracketing published values obtained in adult or pediatric studies demonstrating safety and/or efficacy. Group 1 efavirenz plasma concentrations were observed to be higher in patients receiving fixed-dose combination tablets compared with subjects receiving the individual formulation. In group 2, tenofovir and darunavir exposure was observed to be lower than expected. In group 3, tenofovir and atazanavir administered concomitantly produced exposures similar to those published for adult patients. The 90% CI of AUC and
C
min
for tenofovir overlapped the target range for all combinations. Informal comparisons of treatment groups did not indicate any advantage to any combination with respect to tenofovir exposure. Further study of exposures achieved with antiretrovirals administered in combination is warranted.
Refining Vancomycin Protein Binding Estimates: Identification of Clinical Factors That Influence Protein Binding
Authors: Butterfield Jill M. , Patel Nimish , Pai Manjunath P. , Rosano Thomas G. , Drusano George L. , Lodise Thomas P.
Published: June 2011

While current data indicate only free (unbound) drug is pharmacologically active and is most predictive of response, pharmacodynamic studies of vancomycin have been limited to measurement of total concentrations. The protein binding of vancomycin is thought to be approximately 50%, but considerable variability surrounds this estimate. The present study sought to determine the extent of vancomycin protein binding, to identify factors that modulate its binding, and to create and validate a prediction tool to estimate the extent of protein binding based on individual clinical factors. This single-site prospective cohort study included hospitalized adult patients treated with vancomycin and with a vancomycin serum concentration determination available. Linear regression was used to predict the free vancomycin concentration (
f
[vanco]) and to determine the clinical factors modulating vancomycin protein binding. Among the 50 patients in the study, the mean protein binding was 41.5%. The strongest predictor of
f
[vanco] was the total vancomycin concentration (total [vanco]), and this was modified by dialysis and total protein of ≥6.7 g/dl as covariates. The algebraic expression from the final prediction model was
f
[vanco] = 0.643 + 0.560 × total [vanco] − {0.067 × total [vanco] × D} − {0.071 × total [vanco] × TP} where D = 1 if dialysis dependent or 0 if not dialysis dependent, and TP = 1 if total protein is ≥6.7 g/dl or 0 if total protein is <6.7 g/dl. The
R
2
of the final prediction model was 0.959 (
P
< 0.001). Validation of our model was performed in 13 patients, and the predictive performance was highly favorable (
R
2
was 0.9, and bias and precision were 0.18 and 0.18, respectively). Prediction models such as ours can be utilized in future pharmacokinetics and pharmacodynamics studies evaluating the exposure-response profile and to determine the pharmacodynamic target of interest as it relates to the free concentration.
Analysis of the HD-GYP Domain Cyclic Dimeric GMP Phosphodiesterase Reveals a Role in Motility and the Enzootic Life Cycle of Borrelia burgdorferi
Authors: Sultan Syed Z. , Pitzer Joshua E. , Boquoi Tristan , Hobbs Gerry , Miller Michael R. , Motaleb M. A.
Published: June 2011

HD-GYP domain cyclic dimeric GMP (c-di-GMP) phosphodiesterases are implicated in motility and virulence in bacteria.
Borrelia burgdorferi
possesses a single set of c-di-GMP-metabolizing enzymes, including a putative HD-GYP domain protein, BB0374. Recently, we characterized the EAL domain phosphodiesterase PdeA. A mutation in
pdeA
resulted in cells that were defective in motility and virulence. Here we demonstrate that BB0374/PdeB specifically hydrolyzed c-di-GMP with a

K
m

of 2.9 nM, confirming that it is a functional phosphodiesterase. Furthermore, by measuring phosphodiesterase enzyme activity in extracts from cells containing the
pdeA pdeB
double mutant, we demonstrate that no additional phosphodiesterases are present in
B. burgdorferi
.
pdeB
single mutant cells exhibit significantly increased flexing, indicating a role for c-di-GMP in motility. Constructing and analyzing a
pilZ
pdeB
double mutant suggests that PilZ likely interacts with chemotaxis signaling. While virulence in needle-inoculated C3H/HeN mice did not appear to be altered significantly in
pdeB
mutant cells, these cells exhibited a reduced ability to survive in
Ixodes scapularis
ticks. Consequently, those ticks were unable to transmit the infection to naïve mice. All of these phenotypes were restored when the mutant was complemented. Identification of this role of
pdeB
increases our understanding of the c-di-GMP signaling network in motility regulation and the life cycle of
B. burgdorferi
.
Association between firearm ownership, firearm-related risk and risk reduction behaviours and alcohol-related risk behaviours
Authors: Wintemute Garen J
Published: June 2011

Alcohol use and firearm ownership are risk factors for violent injury and death. To determine whether firearm ownership and specific firearm-related behaviours are associated with alcohol-related risk behaviours, the author conducted a cross-sectional study using Behavioral Risk Factor Surveillance System data for eight states in the USA from 1996 to 1997 (the most recent data available). Altogether, 15 474 respondents provided information on firearm exposure. After adjustment for demographics and state of residence, firearm owners were more likely than those with no firearms at home to have ≥5 drinks on one occasion (OR 1.32; 95% CI 1.16 to 1.50), to drink and drive (OR 1.79; 95% CI 1.34 to 2.39) and to have ≥60 drinks per month (OR 1.45; 95% CI 1.14 to 1.83). Heavy alcohol use was most common among firearm owners who also engaged in behaviours such as carrying a firearm for protection against other people and keeping a firearm at home that was both loaded and not locked away. The author concludes that firearm ownership and specific firearm-related behaviours are associated with alcohol-related risk behaviours.
Obstetrician-gynaecologists' opinions about conscientious refusal of a request for abortion: results from a national vignette experiment
Authors: Rasinski Kenneth A , Yoon John D , Kalad Youssef G , Curlin Farr A
Published: June 2011

Background and objectives

Conscientious refusal of abortion has been discussed widely by medical ethicists but little information on practitioners' opinions exists. The American College of Obstetricians and Gynecologists (ACOG) issued recommendations about conscientious refusal. We used a vignette experiment to examine obstetrician-gynecologists' (OB/GYN) support for the recommendations.

Design

A national survey of OB/GYN physicians contained a vignette experiment in which an OB/GYN doctor refused a requested elective abortion. The vignette varied two issues recently addressed by the ACOG ethics committee—whether the doctor referred and whether the doctor disclosed their objection to the abortion.

Participants and setting

1800 OB/GYN randomly selected physicians were asked to complete a mail survey containing the vignette. The response rate was 66% (n=1154) after excluding 40 ineligible cases.

Measurement

Physicians indicated their approval for the vignette doctor's decision.

Main results

Overall, 43% of OB/GYN physicians responded that the conscientious refusal exercised by the vignette physician was appropriate. 70% rated the vignette doctor as acting appropriately when a referral was made. This dropped to 51% when the doctor disclosed objections to the patient, and to 12% when the doctor disclosed objections and refused to make a referral. Consistent with previous research, males were more likely to support disclosure and refusal to refer. Highly religious physicians supported non-referral but not disclosure.

Conclusion

OB/GYN physicians are less likely to support conscientious refusal of abortion if physicians disclose their objections to patients. This is at odds with ACOG recommendations and with some models of the doctor–patient relationship.
Research, engagement and public bioethics: promoting socially robust science
Authors: Pickersgill Martyn D
Published: June 2011

Citizens today are increasingly expected to be knowledgeable about and prepared to engage with biomedical knowledge. In this article, I wish to reframe this ‘public understanding of science’ project, and place fresh emphasis onpublic understandings of research: an engagement with the everyday laboratory practices of biomedicine and its associated ethics, rather than with specific scientific facts. This is not based on an assumption that non-scientists are ‘ignorant’ and are thus unable to ‘appropriately’ use or debate science; rather, it is underpinned by an empirically-grounded observation that some individuals may be unfamiliar with certain specificities of particular modes of research and ethical frameworks, and, as a consequence, have their autonomy compromised when invited to participate in biomedical investigations. Drawing on the perspectives of participants in my own sociological research on the social and ethical dimensions of neuroscience, I argue that public understanding of biomedical research and its ethics should be developed both at the community level and within the research moment itself in order to enhance autonomy and promote more socially robust science. Public bioethics will have to play a key role in such an endeavour, and indeed will contribute in important ways to the opening up of new spaces of symmetrical engagement between bioethicists, scientists and wider publics—and hence to the democratisation of the bioethical enterprise.
Lost property? Legal compensation for destroyed sperm: a reflection and comparison drawing on UK and French perspectives
Authors: Cordell Sean , Bellivier Florence , Widdows Heather , Noiville Christine
Published: June 2011

In a recent case in the UK, six men stored their sperm before undergoing chemotherapy treatment for cancer in case they proved to be infertile after the treatment. The sperm was not properly stored and as a result was inadvertently destroyed. The men sued the NHS Trust that stored the sperm and were in the end successful.

This paper questions the basis on which the judgement was made and the rationale behind it, namely that the men ‘had ownership’ of the sperm, and that compensation was thus due on the grounds that the men's property had been destroyed. We first argue that the claim is erroneous and enhances the tendency towards the commodification of body parts. We then suggest that the men could have been compensated for the harm done to them without granting property rights, and that this would, at least in philosophical and ethical terms, have been more appropriate. To help illustrate this, we draw on a parallel case in French law in which a couple whose embryos had been destroyed were overtly denied ownership rights in them. Finally, we suggest some possible ethical and practical problems if the proprietary view expressed in the UK ruling were to become dominant in law, with particular focus on the storing of genetic information in biobanks. We conclude that, although compensation claims should not necessarily be ruled out, a ‘no property in the body’ approach should be the default position in cases of detached bodily materials, the alternative being significantly ethically problematic.
MAGNETIC PROPERTIES OF NANOCRYSTALLINE Fe–Ni ALLOYS SYNTHESIZED BY DIRECT AND PULSE ELECTRODEPOSITION
Authors: SANATY-ZADEH A. , RAEISSI K. , SAIDI A.
Published: June 2011

Nanocrystalline iron–nickel alloys are electrodeposited by direct and pulse current densities with the grain sizes between 8–16 nm. XRD patterns showed a variety of structure in alloys from fcc, bcc and mixed (fcc+bcc) by variation of Fe content of alloy. The fcc structure was observed for lower Fe content, dual phase structure for Fe content between 60–70% and bcc structure for higher Fe content. By applying pulse current, an increase in Fe content of alloys was observed. Magnetic property measurements showed a high saturation magnetization for the alloys increased with increase in Fe content and a low coercivity decreased with decrease in grain size for alloys with iron content below 60%.
UNSTABLE CARDIAC SINGULARITIES MAY LEAD TO ATRIAL FIBRILLATION
Authors: WEBBER C. L. , HU Z. , AKAR J. G.
Published: June 2011

A total of 53 atrial electrograms were recorded from 12 human patients diagnosed with different degrees of atrial arrhythmias and fibrillation, but not atrial flutter. The atrial waves were highly complex, noisy, nonuniform, nonlinear, and nonstationary in time and well suited for recurrence quantification analysis (RQA), spectral analysis (FFT) and atrial rate (AR) measurements. Differing degrees of atrial arrhythmias were quantified by measuring singularities in the electrograms. Singularities were defined as the maximum periods of relative isopotential squared (msec2) and presented as unfilled squares along the central line of identity (LOI) on recurrence plots. These nonsolid (unfilled) squares indicate that most singularities were unstable with noisy baselines. All measured variables were plotted against their corresponding unstable singularities. The best correlations were found for variables Vmaxand Laminar over the full range of log10(singularity). That is, the higher the degree of fibrillation the smaller the size of the singularity and the shorter Vmaxand Laminar. The shorter singularities are associated with faster spiral waves. However, since Vmaxand Laminar are direct derivatives of Singularity, this variable remains the sole best quantifier of choice to identify aberrant pacemaker regions.
LOCAL MINIMA-BASED RECURRENCE PLOTS FOR CONTINUOUS DYNAMICAL SYSTEMS
Authors: SCHULTZ AARON P. , ZOU YONG , MARWAN NORBERT , TURVEY MICHAEL T.
Published: June 2011

A major issue in using recurrence plots (RPs) to study dynamical systems is the choice of neighborhood size for thresholding the distance matrix that creates the plot. This is particularly important for continuous dynamical systems as temporal correlations of the trajectory might provide redundant information for recurrence analysis. We suggest an alternative procedure for creating RPs using the local minima provided by the distance profile, which approximately corresponds to the recurrence information in the orthogonal direction. The local minima-based thresholding yields a clean RP of minimized line thickness, that is compared to the plot obtained by the standard radius bases thresholding. New definitions of line segments arising from the local minima-based method are outlined, which yield consistent results with those derived from standard methods. Our preliminary comparison suggests that the newly introduced thresholding technique is more sensitive to small changes in a system's dynamics. We demonstrate our method via the chaotic Lorenz system without the loss of generality.
ACHIRALITY AND LINKING NUMBERS OF LINKS
Authors: MATSUOKA SAORI
Published: June 2011

An oriented and ordered n-component link L in the 3-sphere is said to be achiral if it is ambient isotopic to its mirror image ignoring orientations and ordering of the components. For an oriented and ordered n-component link L, let λL be the product of linking numbers of all 2-component sublinks in L. For n = 4m + 3, where m is a non-negative integer, we show that if L is achiral then λL = 0. And for n ≠ 4m + 3, we show that there exists an n-component achiral link L with λL ≠ 0 by using achiral embeddings of complete graphs with n vertices Kn.
INFLUENCE OF IN-PLANE AXIAL AND SHEAR LOADING ON THE VIBRATION OF METALLIC PLATES
Authors: CARRERA E. , LECCA S. , NALI P. , SOAVE M.
Published: June 2011

This work deals with the vibration problem of metallic plates subjected to combined axial, biaxial and shear in-plane loading. Various type of boundary conditions are considered. Results related to thin plate theories and shear deformation theories are compared to a third-order plate theory including the thickness stretching effects. The Finite Element Method (FEM) is applied on the basis of Carrera Unified Formulation kinematic assumptions. FE matrices are computed by referring to the four-node element. The mixed interpolation of tensorial components technique is used in order to contrast the shear locking for both classical and refined theories. The influence of the in-plane loading (combined axial, biaxial and shear) on plate undamped natural frequencies is illustrated and discussed. Various plate geometries and boundary conditions are considered.
SOLUTE TRANSPORT IN CYCLIC DEFORMED HETEROGENEOUS ARTICULAR CARTILAGE
Authors: ZHANG LIHAI
Published: June 2011

Solute transport in biological tissues is a fundamental process of supplying nutrients to tissue cells. Due to the avascular nature of cartilage, nutrients have to diffuse into the tissue to exert their biological effects. Whilst significant research efforts have been made over last decade towards understanding the solute transport behavior within the cartilage, the effect of dynamic loading on the transport process is still not fully understood. By treating cartilage as a homogeneous tissue, recent theoretical studies generally indicate that physiologically relevant mechanical loading could potentially enhance solute uptake in cartilage. However, like most biological tissues, articular cartilage is actually an inhomogeneous tissue with direction-dependent mechanical properties (such as aggregate modulus and hydraulic permeability). The inhomogeneity of tissue mechanical properties may have considerable influence on solute transport, and thereby need critical investigation. Using an engineering approach, a quantitative theoretical model has been developed in this study to investigate the solute transport behavior in cartilage in consideration of its material inhomogeneity. Using a cylindrical cartilage disk undergoing unconfined cyclic deformation as a case study, the model results demonstrate that inhomogeneous cartilage properties could potentially influence the magnitude and profile of interstitial fluid velocity and pressure throughout the cartilage. Furthermore, the enhancement of solute transport by dynamic loading is depth-dependent due to the inhomogeneous distribution of material properties.
Late Miocene–Holocene canyon incision in the western Altiplano, northern Chile: tectonic or climatic forcing?
Authors: García Marcelo , Riquelme Rodrigo , Farías Marcelo , Hérail Gérard , Charrier Reynaldo
Published: June 2011

Major fluvial incision (600–1000 m) affecting the Coastal Cordillera and Central Depression of northern Chile is analysed to evaluate supposed coeval uplift of the Altiplano and/or climatic changes in the Atacama Desert. The timing of the beginning of incision is constrained by the age of deposition of the Central Depression top. In the north (18–19°S), this top corresponds to fluvial gravels accumulated between 11.9 ± 0.6 Ma and 8.3 ± 0.5 Ma, which are genetically related to semiarid climate and to an eastward poorly dissected parallel drainage network that developed between 15.0 ± 0.6 and 11.2 ± 0.6 Ma; thus, gravel deposition ended at 11.9–11.2 Ma. To the south (19–20°S), the Central Depression top corresponds to
c
. 6 Ma alluvial deposits. Stratigraphically determined canyon ages and knickzone locations indicate that southward dissection began later and/or developed under a regime of lower erosion capacity owing to drier climate. Vertical incision rate evolution is compatible with eastward knickzone migration. Dissection required a considerable altitude difference between ancient and present-day river base levels, which was achieved predominantly by basin infill on an already partially elevated bedrock. Therefore subsequent incision would have been triggered by local semiarid climatic periods rather than by contemporaneous surface uplift. Exoreic canyons occur when climatic conditions in the catchments are arid–semiarid whereas endoreism is developed when these conditions in catchments are hyperarid.
Age constraints and geochemistry of the Ordovician Tyrone Igneous Complex, Northern Ireland: implications for the Grampian orogeny
Authors: Cooper M.R. , Crowley Q.G. , Hollis S.P. , Noble S.R. , Roberts S. , Chew D. , Earls G. , Herrington R. , Merriman R.J.
Published: June 2011

The Tyrone Igneous Complex is one of the largest areas of ophiolitic and arc-related rocks exposed along the northern margin of Iapetus within the British and Irish Caledonides. New U–Pb zircon data and regional geochemistry suggest that the Tyrone Plutonic Group represents the uppermost portions of a
c
. 480 Ma suprasubduction-zone ophiolite accreted onto an outboard segment of Laurentia prior to 470.3 ± 1.9 Ma. The overlying Tyrone Volcanic Group formed as an island arc that collided with the Laurentian margin during the Grampian phase of the Caledonidan orogeny. Early magmatism is characterized by transitional to calc-alkaline, light REE (LREE)-enriched island-arc signatures, with an increasing component of continentally derived material up sequence. Tholeiitic rhyolites with flat to U-shaped REE profiles and LREE-depleted basalts, located stratigraphically below a
c
. 473 Ma rhyolite of the upper Tyrone Volcanic Group, suggest initiation of intra-arc rifting at
c
. 475 Ma. Metamorphic cooling ages from the Tyrone Central Inlier imply arc–continent collision before 468 ± 1.4 Ma, with the emplacement of the Tyrone Volcanic Group onto the margin. A suite of 470.3 ± 1.9 Ma to 464.3 ± 1.5 Ma calc-alkaline intrusions are associated with the continued closure of Iapetus.

Supplementary material:

Geochemical data and petrography are available at
http://www.geolsoc.org.uk/SUP18467
.
Multithreaded Simulation for Synchronous Dataflow Graphs
Authors: Hsu Chia-Jui , Pino José Luis , Bhattacharyya Shuvra S.
Published: June 2011

For system simulation, Synchronous DataFlow (SDF) has been widely used as a core model of computation in design tools for digital communication and signal processing systems. The traditional approach for simulating SDF graphs is to compute and execute static schedules in single-processor desktop environments. Nowadays, however, multicore processors are increasingly popular desktop platforms for their potential performance improvements through thread-level parallelism. Without novel scheduling and simulation techniques that explicitly explore thread-level parallelism for executing SDF graphs, current design tools gain only minimal performance improvements on multicore platforms. In this article, we present a new multithreaded simulation scheduler, called MSS, to provide simulation runtime speedup for executing SDF graphs on multicore processors. MSS strategically integrates graph clustering, intracluster scheduling, actor vectorization, and intercluster buffering techniques to construct InterThread Communication (ITC) graphs at compile-time. MSS then applies efficient synchronization and dynamic scheduling techniques at runtime for executing ITC graphs in multithreaded environments. We have implemented MSS in the Advanced Design System (ADS) from Agilent Technologies. On an Intel dual-core, hyper-threading (4 processing units) processor, our results from this implementation demonstrate up to 3.5 times speedup in simulating modern wireless communication systems (e.g., WCDMA3G, CDMA 2000, WiMax, EDGE, and Digital TV).
40nm CMOS 0.35V-Optimized Standard Cell Libraries for Ultra-Low Power Applications
Authors: Abouzeid Fady , Clerc Sylvain , Firmin Fabian , Renaudin Marc , Sas Tiempo , Sicard Gilles
Published: June 2011

Ultra-low voltage is now a well-known solution for energy constrained applications designed using nanometric process technologies. This work is focused on setting up an automated methodology to enable the design of ultra-low voltage digital circuits exclusively using standard EDA tools. To achieve this goal, a 0.35V energy-delay optimized library was developed. This library, fully compliant with standard library design flow and characterization, was verified through the design and fabrication of a BCH decoder circuit, following a standard front-end to back-end flow. At 0.33V, it performs at 600 kHz with a dynamic energy consumption reduced by a factor 14x from nominal 1.1V. Based on this design, experiments, and preliminary silicon results, two additional libraries were developed in order to enhance future ultra-low voltage circuit performance.
Emerging In Vivo Analyses of Cell Function Using Fluorescence Imaging
Authors: Lippincott-Schwartz Jennifer
Published: June 2011

Understanding how cells of all types sense external and internal signals and how these signals are processed to yield particular responses is a major goal of biology. Genetically encoded fluorescent proteins (FPs) and fluorescent sensors are playing an important role in achieving this comprehensive knowledge base of cell function. Providing high sensitivity and immense versatility while being minimally perturbing to a biological specimen, the probes can be used in different microscopy techniques to visualize cellular processes on many spatial scales. Three review articles in this volume discuss recent advances in probe design and applications. These developments help expand the range of biochemical processes in living systems suitable for study. They provide researchers with exciting new tools to explore how cellular processes are organized and their activity regulated in vivo.
Distinct functions for direct and transthalamic corticocortical connections
Authors: Sherman S. Murray , Guillery R. W.
Published: June 2011

Essentially all cortical areas receive thalamic inputs and send outputs to lower motor centers. Cortical areas communicate with each other by means of direct corticocortical and corticothalamocortical pathways, often organized in parallel. We distinguish these functionally, stressing that the transthalamic pathways are class 1 (formerly known as “driver”) pathways capable of transmitting information, whereas the direct pathways vary, being either class 2 (formerly known as “modulator”) or class 1. The transthalamic pathways provide a thalamic gate that can be open or closed (and otherwise more subtly modulated), and these inputs to the thalamus are generally branches of axons with motor functions. Thus the transthalamic corticocortical pathways that can be gated carry information about the cortical processing in one cortical area and also about the motor instructions currently being issued from that area and copied to other cortical areas.
Synthesis, Characterization, and Electrochemical Study of Tetradentate Ruthenium‐Schiff Base Complexes: Dioxygen Activation with a Cytochrome P450 Model Using 1‐ or 2‐Methylimidazole as Axial Bases
Authors: Ourari Ali , Khelafi Mostefa , Aggoun Djouhra , Bouet Gilles , Khan Mustayeen A.
Published: June 2011

Salicylaldehyde, 2‐hydroxyacetophenone, and 3,5‐dichlorosalicylaldehyde react with 1,2‐diaminoethane to give three symmetrical Schiff bases H2L1, H2L2, and H2L3, respectively. With Ru(III) ions, these ligands lead to three complexes: Ru(III)ClL1 (1), Ru(III)ClL2 (2), and Ru(III)ClL3 (3). The purity of these compounds was estimated by TLC technique and microanalysis while their structures were supported by the usual spectroscopic methods such as NMR, infrared, and electronic spectra. The cyclic voltammetry in acetonitrile showed irreversible waves for all three ligands. Under the same experimental conditions, it was proved that the ruthenium is coordinated in the three complexes 1, 2, and 3 showing quasireversible redox systems. The behavior of these complexes and their comparison with cytochrome P450 are investigated using them as catalysts in the presence of molecular oxygen with an apical nitrogen base: 1‐ or 2‐methylimidazole.
Identification of NF‐κB Modulation Capabilities within Human Intestinal Commensal Bacteria
Authors: Lakhdari Omar , Tap Julien , Béguet-Crespel Fabienne , Le Roux Karine , de Wouters Tomas , Cultrone Antonietta , Nepelska Malgorzata , Lefèvre Fabrice , Doré Joël , Blottière Hervé M.
Published: June 2011

The intestinal microbiota plays an important role in modulation of mucosal immune responses. To seek interactions between intestinal epithelial cells (IEC) and commensal bacteria, we screened 49 commensal strains for their capacity to modulate NF‐κB. We used HT‐29/kb‐seap‐25 and Caco‐2/kb‐seap‐7 intestinal epithelial cells and monocyte‐like THP‐1 blue reporter cells to measure effects of commensal bacteria on cellular expression of a reporter system for NF‐κB. Bacteria conditioned media (CM) were tested alone or together with an activator of NF‐κB to explore its inhibitory potentials. CM from 8 or 10 different commensal species activated NF‐κB expression on HT‐29 and Caco‐2 cells, respectively. On THP‐1, CM from all but 5 commensal strains stimulated NF‐κB. Upon challenge with TNF‐α or IL‐1β, some CM prevented induced NF‐κB activation, whereas others enhanced it. Interestingly, the enhancing effect of some CM was correlated with the presence of butyrate and propionate. Characterization of the effects of the identified bacteria and their implications in human health awaits further investigations.
Endopancreatic Bile Duct Cholangiocarcinoma in a Patient with Peutz-Jeghers Syndrome
Authors: Charalabopoulos Alexandros K. , Krivan Sylvia P. , Machairas Nikolas A. , Evangelos Misiakos P. , Machairas Anastasios N.
Published: June 2011

Peutz-Jeghers syndrome is a rare autosomal dominant inherited disease characterized by a special type of hamartomatous gastrointestinal polyps combined with mucocutaneous melanin pigmentations. Patients with the syndrome have a high risk of developing neoplasia, with colon, small bowel, and stomach being the most common gastrointestinal sites. Herein, we present the occurrence of a rare tumor in patients with Peutz-Jeghers syndrome; a cholangiocarcinoma of the endopancreatic bile duct. A minireview is also presented. It can be concluded that cholangiocarcinoma remains a possible diagnosis in PJS patients, as in others that present with biliary obstruction. PJS patients may be at higher risk than others in view of their propensity for malignancy.
Carbon Dioxide Insufflation in Routine Colonoscopy Is Safe and More Comfortable: Results of a Randomized Controlled Double-Blinded Trial
Authors: Geyer M. , Guller U. , Beglinger C.
Published: June 2011

Many patients experience pain and discomfort after colonoscopy. Carbon dioxide (CO2) can reduce periprocedural pain although air insufflation remained the standard procedure. The objective of this double-blinded, randomized controlled trial was to evaluate whether CO2 insufflation does decrease pain and bloating during and after colonoscopy compared to room air. Methods. 219 consecutive patients undergoing colonoscopy were randomized to either CO2 or air insufflation. Propofol was used in all patients for sedation. Transcutaneous CO2 was continuously measured with a capnograph as a safety parameter. Pain, bloating, and overall satisfaction were assessed at regular intervals before and after the procedure. Results(data are mean ±SD). 110 patients were randomized to CO2 and 109 to room air. The baseline characteristics were similar in both groups. The mean propofol dose was not different between the treatments, as were the time to reach the ileum and the withdrawal time. pCO2 at the end of the procedure was  mmHg (CO2 group) versus  mmHg in the room air group (). No relevant complication occurred in either group. There was significantly less bloating for the CO2 group during the postprocedural recovery period () and over the 24-hour period (). Also, patients with CO2 insufflation experienced significantly less pain (). Finally, a higher overall satisfaction (
) was found in the CO2 group. Conclusions. This trial provides compelling evidence that CO2 insufflation significantly reduces bloating and pain after routine colonoscopy in propofol-sedated patients. The procedure is safe with no significant differences in CO2 between the two groups.
Finite Element Analysis with Iterated Multiscale Analysis for Mechanical Parameters of Composite Materials with Multiscale Random Grains
Authors: Li Youyun , Pan Yuqing , Zheng Jianlong , Zhou Chiqing , Wang Desheng
Published: June 2011

Based on the iterated statistically multiscale analysis (SMSA), we present the convergence of the equivalent mechanical parameters (effective moduli), obtain the error result, and prove the symmetric, positive and definite property of the equivalent mechanical parameters tensor computed by the finite element method. The numerical results show the proved results and illustrate that the SMSA‐FE algorithm is a rational method for predicting the equivalent mechanical parameters of the composite material with multiscale random grains. In conclusion, we discuss the future work for the inhomogeneous composite material with multiscale random grains.
Cancer Cachexia: Mechanisms and Clinical Implications
Authors: Donohoe Claire L. , Ryan Aoife M. , Reynolds John V.
Published: June 2011

Cachexia is a multifactorial process of skeletal muscle and adipose tissue atrophy resulting in progressive weight loss. It is associated with poor quality of life, poor physical function, and poor prognosis in cancer patients. It involves multiple pathways: procachectic and proinflammatory signals from tumour cells, systemic inflammation in the host, and widespread metabolic changes (increased resting energy expenditure and alterations in metabolism of protein, fat, and carbohydrate). Whether it is primarily driven by the tumour or as a result of the host response to the tumour has yet to be fully elucidated. Cachexia is compounded by anorexia and the relationship between these two entities has not been clarified fully. Inconsistencies in the definition of cachexia have limited the epidemiological characterisation of the condition and there has been slow progress in identifying therapeutic agents and trialling them in the clinical setting. Understanding the complex interplay of tumour and host factors will uncover new therapeutic targets.
A Giant Euthyroid Endemic Multinodular Goiter with No Obstructive or Compressive Symptoms
Authors: Nada Ahmed , Mohamed Ahmed Ashraf , Vilallonga Ramon , Armengol Manuel , Moustafa Ibrahim
Published: June 2011

Diffusely enlarged thyroid glands (goitres) are becoming increasingly infrequent. However, in some geographical areas they are still relatively common and can cause compressive symptoms involving the trachea, oesophagus, and recurrent laryngeal nerve. Surgical treatment of diffusely enlarged thyroid glands requires a high level of expertise and may lead to severe complications. Here we present a case report of surgical treatment of an extremely enlarged thyroid gland, found in a 61-year-old female patient. The patient underwent surgery, and a thyroidectomy was performed. The resulting specimen weighed 4.7 kg (10.4 lbs). Histopathological examination revealed a multinodular goitre with multiple cysts and areas of haemorrhage and necrosis. Surgical excision can immediately resolve local symptoms and is often recommended when substernal extension is evident. To the best of our knowledge, this is the largest thyroid gland ever reported in the literature. Only experienced surgeons should treat large thyroid goitres. Ideally, large thyroid goitres should be treated before they reach a substernal component, otherwise any sudden growth in gland size could seriously compromise respiration.