bluuebunny/crossref_metadata_2025 huggingface dataset:
Are we really doing better with Hem‐o‐lok in VATS?
Authors: Lv Xiayi , Wang Zhitian , Cha Yuxin , Hu Jian , Rusidanmu Aizemaiti , He Zhehao
Published: June 2012

Background:  Due to advances in clip design, new types of surgical ligation clips are available that may reduce clip failure and improve function, but in the field of minimally invasive thoracic surgery, experience of using Hem‐o‐lok for pulmonary artery ligation is limited.

Methods:  To assess risk factors and predictors of failure of the Hem‐o‐lok vascular clip, using vessels harvested from a porcine model.

Results:  The Hem‐o‐lok clip had the worst holding strength compared to other clips. Its hemostatic ability for pulmonary vessels was far less stable compared with renal and hepatic vessels. The Hem‐o‐lok clip either leaked or burst when the vessel to which it was applied was cut flush. The clip became even more likely to fail if the vessel sleeve was mobilized too “clean.”

Conclusion:  Our experiment proved that the use of Hem‐o‐lok clips in video‐assisted thoracoscopic surgery (VATS) has some potential risk. We recommend that all possible care be taken when it is applied to pulmonary vessels during VATS. Leaving some tissues around vessels may increase the thickness of the vessel, which, in turn, may increase the holding strength.
Accountable Governance in Corporate Groups: The Interrelationship of Law and Accounting
Authors: Hadden Tom
Published: June 2012

The complex structures of multinational corporate groups and their many subsidiaries facilitate the concealment of internal financial transactions and the profitability and taxation of operations in different jurisdictions. Current provisions for corporate governance by independent directors and auditors in ultimate holding companies fail to provide relevant information for most major stakeholders. Lawyers and accountants need to develop new structures for corporate governance and corporate social responsibility at every level, especially in respect of national taxation, to meet the proper interests of shareholders, employees, local communities and national governments, and to assist in the transition from centrally controlled and often abusive, to more participatory and responsible capitalism. Auditors have a key role in this and should be required to report on issues of variability in financial statements and to carry out special audits on matters of major concern.
Superannuation in Society: What are the Accountability Relationships and is there a Role for (Group) Accounting?
Authors: Gordon Isabel
Published: June 2012

Superannuation fund reporting is a topical issue: it is in a state of flux and currently on the Australian Accounting Standards Board (AASB) work program for 2012, with the release of ED 223 Superannuation Entities in December 2011. Issues under debate include uncertainty regarding the users of superannuation financial reports, and the application of the principle of ‘transaction neutrality’ to accounting for corporate groups by superannuation entities. Accountability reporting by superannuation funds has remained largely unchanged since the introduction of compulsory superannuation 20 years ago. This paper describes the changing nature of superannuation from a managerial gratuity to a type of deferred pay, and how accounting for superannuation is likely to increase in significance as it responds to the shifting economic nature of superannuation, especially since the global financial crisis. This paper uses basic content analysis to analyse member submissions to the Australian Government's Review into Governance, Efficiency, Structure and Operation of Australia's Superannuation System 2009, and submissions to the AASB's consultation paper on consolidation accounting for superannuation entities in 2007. Limited characterisations of members as being not interested in financial reporting are out of step with the underlying nature of superannuation, and will likely change as the economic significance of superannuation increases in the future.
Differences in weight status and energy‐balance related behaviours according to ethnic background among adolescents in seven countries in Europe: the ENERGY‐project
Authors: Brug J. , van Stralen M. M. , ChinAPaw M. J. M. , De Bourdeaudhuij I. , Lien N. , Bere E. , Singh A. S. , Maes L. , Moreno L. , Jan N. , Kovacs E. , Lobstein T. , Manios Y. , te Velde S. J.
Published: June 2012

Objective

The aim of this study was to explore differences in weight status and energy balance behaviours according to ethnic background among adolescents across Europe.

Methods

A school‐based survey among 10–12‐year‐old adolescents was conducted in seven European countries. Weight, height and waist circumference were measured; engagement in physical activity, sedentary and dietary behaviour, and sleep duration was assessed by child and parent‐report. A distinction between native and non‐native ethnic background was based on language spoken at home, and the parents' country of birth. Analyses were conducted with and without adjustment for parental education.

Results

With valid data on both indicators of ethnic background for 5149 adolescents, 7307 adolescents (52% girls; 11.6 ± 0.7 years) participated. Significantly higher prevalence of overweight, obesity, body mass index and waist circumference were observed among non‐native compared with native adolescents. Non‐native adolescents had less favourable behavioural patterns (sugary drinks, breakfast skipping, sport, TV and computer time, hours of sleep) with the exception of active transport to school. Similar patterns were observed for both indicators of ethnicity, and in most of the separate countries; however, in Greece, weight status indicators were better among non‐native adolescents. After adjustment for parental education, most differences remained significant according to country of origin of the parents, but not according to language spoken at home.

Conclusion

Adolescents of native ethnicity of the country of residence have, in general, more favourable weight status indicators and energy balance‐related behaviours than adolescents of non‐native ethnicity across Europe.
Experimental Investigation of Turbine Stator Well Rim Seal, Re-Ingestion and Interstage Seal Flows Using Gas Concentration Techniques and Displacement Measurements
Authors: Eastwood D. , Coren D. D. , Long C. A. , Atkins N. R. , Childs P. R. N. , Scanlon T. J. , Guijarro-Valencia A.
Published: June 2012

Gas turbine engine performance requires effective and reliable internal cooling over the duty cycle of the engine. Life predictions for rotating components subject to the main gas path temperatures are vital. This demands increased precision in the specification of the internal air system flows which provide turbine stator well cooling and sealing. This in turn requires detailed knowledge of the flow rates through rim seals and interstage labyrinth seals. Knowledge of seal movement and clearances at operating temperatures is of great importance when prescribing these flows. A test facility has been developed at the University of Sussex, incorporating a two stage turbine rated at 400 kW with an individual stage pressure ratio of 1.7:1. The mechanical design of the test facility allows internal cooling geometry to be rapidly reconfigured, while cooling flow rates of between 0.71 CW, ENT and 1.46 CW, ENT, may be set to allow ingress or egress dominated cavity flows. The main annulus and cavity conditions correspond to in cavity rotational Reynolds numbers of 1.71 × 106< Reϕ<1.93 × 106. Displacement sensors have been used to establish hot running seal clearances over a range of stator well flow conditions, allowing realistic flow rates to be calculated. Additionally, gas seeding techniques have been developed, where stator well and main annulus flow interactions are evaluated by measuring changes in gas concentration. Experiments have been performed which allow rim seal and re-ingestion flows to be quantified. It will be shown that this work develops the measurement of stator well cooling flows and provides data suitable for the validation of improved thermo-mechanical and CFD codes, beneficial to the engine design process.
Experimental Study of Low Temperature Diesel Combustion Sensitivity to Engine Operating Parameters
Authors: McTaggart-Cowan G. P. , Cong S. , Garner C. P. , Wahab E. , Peckham M.
Published: June 2012

This work elucidated which engine operating parameters have the greatest influence on Low temperature diesel combustion (LTC) and emissions. Key parameters were selected and evaluated at low and intermediate speed and load conditions using fractional factorial and Taguchi orthogonal experimental designs. The variations investigated were: about ± 5% in EGR rate, fuel injection quantity and engine speed respectively; and ± 10 °C in intake charge temperature. The half-fractional factorial results showed that the interactions among these parameters were negligible for a specific load/speed point. The Taguchi orthogonal method could be used as an efficient DoE tool for studying the multi-parameter ‘small-scale transients’ that a diesel engine would be likely to encounter when operating in LTC modes. LTC showed the most significant sensitivity to EGR rate variations, where an increase from 60% to 63% in EGR rate doubled THC and CO emissions and reduced combustion stability. LTC was also sensitive to the fuel injection quantity with an increase in injected mass lowering the overall oxygen-fuel ratio and thereby increasing THC and CO emissions. These two parameters influenced the oxygen concentration in the intake charge; which was identified to be a decisive parameter for the LTC combustion and emissions. Intake charge temperature affected the total charge quantity trapped in the cylinder and showed noticeable influence on CO emissions for the low speed intermediate load condition. Variations in engine speed showed a negligible influence on the LTC combustion processes and emissions.
Multiple Pantograph Interaction With Catenaries in High-Speed Trains
Authors: Pombo João , Ambrósio Jorge
Published: June 2012

The limitation on the top velocity of high-speed trains concerns the ability to supply the proper amount of energy required to run the engines through the catenary-pantograph interface. Due to the loss of contact, not only the energy supply is interrupted, but also arching between the collector bow of the pantograph and the contact wire of the catenary occurs, leading to the deterioration of the functional conditions of the two systems. An alternative would be to increase the contact force between the two systems. But such force increase would lead to a rapid wear of the contact strip of the pantograph and of the contact wire with negative consequences on the durability of the systems. These situations require that the dynamics of the pantograph-catenary are properly modeled and that software used for analysis, design, or to support maintenance decisions is not only accurate and efficient, but also allows for modeling all details relevant to the train overhead energy collector operation. This work presents a fully three-dimensional methodology for the computational analysis of the interaction between catenary and pantographs. The finite element method (FEM) is used to support the modeling of the catenary, while a multibody (MB) dynamics methodology is applied to support the pantograph modeling. The contact between the two subsystems is described using a penalty contact formulation. A high-speed co-simulation procedure is proposed to ensure the communication between the two methodologies. In order to validate the formulation and models developed, the numerical results are compared against experimental data. The proposed methodology is then applied to study the interaction of multiple pantographs of a high-speed train with the catenary. The results show that the passage of the front pantograph excites the catenary, leading to the deterioration of the contact conditions on the rear one.
Characteristics of Mean Droplet Size Produced by Spinning Disk Atomizers
Authors: Ahmed Mahmoud , Youssef M. S.
Published: June 2012

Characteristics of mean droplet size of spray produced by spinning disk atomizers were experimentally investigated. The phase-doppler particle analyzer (PDPA) was used to measure the droplet size of water spray in the downstream distance along the spray trajectory. Effects of various operating conditions on the mean diameter had been studied. The studied variables were: the rotational speed in the range of 838 to 1677 rad/s (8,000–16,000 rpm), the liquid flow rate in the range of 0.56 to 2.8 × 10−6 m3/s (2–10 L/h), the disk diameter in the range of 0.04 to 0.12 m, and the downstream tangential distance along the spray trajectory of up to 0. 24 m. The Sauter mean diameter (d32) was used to represent the mean of generated spray droplet sizes. The results indicated that the Sauter mean diameter can be correlated with dimensionless groups, such as the Reynolds number, Weber number, flow coefficient, and the ratio of downstream distance to disk diameter. Based on this correlation, it was found that the Sauter mean diameter (d32) increases as the downstream tangential distance, and liquid flow rate increase. Similarly, a decrease of rotational speed and disk diameter results in an increase in the Sauter mean diameter (d32). A comparison between the developed correlation and correlations obtained by other researchers has been presented and discussed in detail.
Analysis and Optimization of a Vaned Diffuser in a Mixed Flow Pump to Improve Hydrodynamic Performance
Authors: Kim Jin-Hyuk , Kim Kwang-Yong
Published: June 2012

Hydrodynamic analysis and an optimization of a vaned diffuser in a mixed-flow pump are performed in this work. Numerical analysis is carried out by solving three-dimensional Reynolds-averaged Navier-Stokes equations using the shear stress transport turbulence model. A validation of numerical results is conducted by comparison with experimental data for the head, power, and efficiency. An optimization process based on a radial basis neural network model is performed with four design variables that define the straight vane length ratio, the diffusion area ratio, the angle at the diffuser vane tip, and the distance ratio between the impeller blade trailing edge and the diffuser vane leading edge. Efficiency as a hydrodynamic performance parameter is selected as the objective function for optimization. The objective function is numerically assessed at design points selected by Latin hypercube sampling in the design space. The optimization yielded a maximum increase in efficiency of 9.75% at the design flow coefficient compared to a reference design. The performance curve for efficiency was also enhanced in the high flow rate region. Detailed internal flow fields between the reference and optimum designs are analyzed and discussed.
Rate Decline Curves Analysis of a Vertical Fractured Well With Fracture Face Damage
Authors: Lei Wang , Xiao-dong Wang , Xu-min Ding , Li Zhang , Chen Li
Published: June 2012

Rate decline analysis is a significant method for predicting well performance. Previous studies on rate decline analysis of fractured wells are all based on homogeneous reservoirs rather than homogeneous ones considering fracture face damage. In this article, a well model intercepted by a finite conductivity vertical fracture with fracture face damage is established to investigate how face damage factor affects the productivity of fractured well. Calculative results show that in transient flow, dimensionless rate decreases with the increase of fracture face damage and in pseudo steady-state flow, all curves under different face damage factors coincide with each other. Then, a new pseudo steady-state analytic formula and its validation are presented. Finally, new Blasingame type curves are established. It is shown that the existence of fracture damage would decrease the rate when time is relatively small, so fracture damage is an essential factor that we should consider for type curves analysis. Compared with traditional type curves, new type curves could solve the problem of both variable rate and variable pressure drop for fractured wells with fracture face damage factor. A gas reservoir example is performed to demonstrate the methodology of new type curves analysis and its validation for calculating important formation parameters.
Drilling Time Reduction Through an Integrated Rock Mechanics Analysis
Authors: Nes Olav-Magnar , Fjær Erling , Tronvoll Johan , Kristiansen Tron G. , Horsrud Per
Published: June 2012

A working methodology to minimize wellbore stability problems has been established through the use of unique laboratory tests, an experimental database for fluid-rock interaction and physical properties of shales, and an integrated modeling approach utilizing different types of experimental and field data. The model simulations provide output accounting for a wide range of input parameters such as well inclination, mud chemistry, rock mechanical properties, field stresses and pressures, formation anisotropy, and shale mineralogy. The model output can subsequently be used to diagnose field drilling problems or to design drilling operations. As an example, data from a high pressure/high temperature (HP/HT) field offshore Mid-Norway as well as a field in the overpressured shales in the southern part of the Norwegian North Sea have been analyzed and compared.
Comparative investigation of elastic properties in a trabecula using micro-Brillouin scattering and scanning acoustic microscopy
Authors: Kawabe Masahiko , Fukui Kenji , Matsukawa Mami , Granke Mathilde , Saïed Amena , Grimal Quentin , Laugier Pascal
Published: June 2012

Micro-Brillouin scattering (μ-BR) and a 200 MHz scanning acoustic microscope (SAM) with similar spatial resolutions were applied to evaluate tissue elastic properties in two directions in a trabecula. Acoustic impedance measured by SAM was in the range of 5–9 Mrayl. Wave velocities determined by μ-BR were in the range of (4.75–5.11) × 103 m/s. Both exhibited a similar trend of variation across the trabecula and were significantly correlated (R2 = 0.63–0.67, p < 0.01). μ-BR is useful for the evaluation of tissue stiffness within a trabecula. Combined with SAM or nanoindentation, it can provide additional information to assess elastic anisotropy at the micro-scale.
Identifying Influential and Susceptible Members of Social Networks
Authors: Aral Sinan , Walker Dylan
Published: June 2012

Who Influences Who?

A goal in social science is how to assess people's influence over one.
Aral and Walker
(p.
337
, published online 21 June) describe a generalized method for identifying influential and susceptible members of social networks based on large-scale in vivo randomized experimentation. The method was used to estimate peer effects in consumer demand for a commercial Facebook application in a representative sample of 12 million Facebook users. Older users were more influential than younger users, women were more influential over men than men over women, and married individuals were the least susceptible to influence in the decision to adopt the product studied.
Human α-Defensin 6 Promotes Mucosal Innate Immunity Through Self-Assembled Peptide Nanonets
Authors: Chu Hiutung , Pazgier Marzena , Jung Grace , Nuccio Sean-Paul , Castillo Patricia A. , de Jong Maarten F. , Winter Maria G. , Winter Sebastian E. , Wehkamp Jan , Shen Bo , Salzman Nita H. , Underwood Mark A. , Tsolis Renee M. , Young Glenn M. , Lu Wuyuan , Lehrer Robert I. , Bäumler Andreas J. , Bevins Charles L.
Published: June 2012

Netting the Bad Guys

Antimicrobial peptides are an evolutionarily conserved component of innate immunity in the intestine. One family, α-defensins, typically exert their antimicrobial effects through microbicidal activity against bacteria. Humans express only two α-defensins, human defensin 5 (HD5) and HD6. HD5 exhibits bactericidal activity and plays a role in shaping the bacterial composition of the gut. HD6, on the other hand, does not show bactericidal activity and its function in the gut is unclear. Now,

Chu
et al.

(p.
477
, published online 21 June; see the Perspective by

Ouellette and Selsted

) show that HD6 protects against bacterial pathogens. Rather than killing them directly, HD6 binds to bacteria surface proteins and, through a process of self-assembly, forms fibrils and nanonets that ensnare invading bacterial pathogens.
Kepler-36: A Pair of Planets with Neighboring Orbits and Dissimilar Densities
Authors: Carter Joshua A. , Agol Eric , Chaplin William J. , Basu Sarbani , Bedding Timothy R. , Buchhave Lars A. , Christensen-Dalsgaard Jørgen , Deck Katherine M. , Elsworth Yvonne , Fabrycky Daniel C. , Ford Eric B. , Fortney Jonathan J. , Hale Steven J. , Handberg Rasmus , Hekker Saskia , Holman Matthew J. , Huber Daniel , Karoff Christopher , Kawaler Steven D. , Kjeldsen Hans , Lissauer Jack J. , Lopez Eric D. , Lund Mikkel N. , Lundkvist Mia , Metcalfe Travis S. , Miglio Andrea , Rogers Leslie A. , Stello Dennis , Borucki William J. , Bryson Steve , Christiansen Jessie L. , Cochran William D. , Geary John C. , Gilliland Ronald L. , Haas Michael R. , Hall Jennifer , Howard Andrew W. , Jenkins Jon M. , Klaus Todd , Koch David G. , Latham David W. , MacQueen Phillip J. , Sasselov Dimitar , Steffen Jason H. , Twicken Joseph D. , Winn Joshua N.
Published: June 2012

So Close and So Different

In our solar system, the rocky planets have very distinct orbits from those of the gas giants.

Carter
et al.

(p.
556
, published online 21 June) report on a planetary system where this pattern does not apply, posing a challenge to theories of planet formation. Data from the Kepler space telescope reveal two planets with radically different densities orbiting the same star with very similar orbital periods. One planet has a rocky Earth-like composition and the other is akin to Neptune.
Field guide for the historical mining site of Mineral de Pozos, Guanajuato, east-central Mexico
Authors: Carrillo-Chávez Alejandro , Levresse Gilles , Reyes Juventino Martínez
Published: June 2012

Silver and gold mineralization was discovered in the late 1600s in the epithermal sulfide-rich veins of Mineral de Pozos Mining District, northeast Guanajuato state, Mexico. The main exploitation period of this mining district was between 1888 and 1922, with sporadic activities until 1942. Exploitation of the deposit is estimated at 1,200,000 tons of ore with average of 202 g/ton silver, and 11.83 g/ton Au. Mineral waste materials (more than 1 million tons) are scattered along the area on the main creeks and in the ancient processing plants (Haciendas de Beneficio). In this field guide, we present brief descriptions of the mineralization, the geology of the area, some of the ancient processing plants, and the potential dispersion of metals derived from the mine tailings into the environment (soil, sediments, and groundwater). Despite the relatively high concentrations of As and Pb in groundwater (0.011–0.090 mg/l As and 0.025–0.035 mg/l Pb), we consider that these values represent natural background values rather than contamination derived from anthropogenic input. However, we consider that Zn is the only metal potentially derived from mining activities being released to the environment. The historical processing plants offer a very interesting perspective of the more than a century old mining activities.
Engineering geology approach to the effects of land subsidence in Mexico City
Authors: Cerca Mariano , Carreón-Freyre Dora , López-Quiroz Penélope , Ovando-Shelley Efraín , Doin Marie Pierre , Gutierrez-Calderón Raúl , González-Hernández Marcos , Jimenez-Sánchez Alejandra , Blancas-Dominguez Daniel
Published: June 2012

The modern Mexico Megacity occupies almost a third of the surface of the Valley of Mexico, and it is exposed to natural and man-induced hazards affecting many aspects of urban development. Land subsidence is a geo-hazard imposing important constraints in the urban development by the gradual decrease in elevation of the land surface. This is caused either naturally, by the extraction of water, oil, minerals, or gas from the subsurface, or by the interaction between natural and anthropogenic forces. In this field trip guide we examine regional land subsidence and the vulnerability to fracturing of the lacustrine soils. Groundwater has been over-exploited for human consumption in Mexico City during the past 70 years, leading to a dramatic decline of piezometric levels and the associated land and subsoil deformation. Interdisciplinary research from geologists and engineers may play an important role in understanding the relationship between geological processes and the suitability of land for urban use.
Geology and tectonics of the southeastern portion of the Sierra de Guanajuato
Authors: Aranda-Gómez José Jorge , Dávila-Harris Pablo , Vassallo-Morales Luis Fernando , Godchaux Martha , Bonnichsen Bill , Martínez-Reyes Juventino , Aguirre-Díaz Gerardo de Jesús , Ortega-Rivera Maria Amabel
Published: June 2012

Guanajuato has a long history (450 years) of mineral exploitation and remarkable silver and gold production from a complex system of fault-veins. Despite this, it is only in the past 40 years that the systematic study of its geology has been conducted. Mid-Tertiary epithermal veins occur in all the Mesozoic and Paleogene rock units exposed in the mining district, and mineralization seems to be the result of the combination of several geologic factors, such as the occurrence of greenschists in the basal complex, a thick sequence of Early Paleogene red beds overlain by a thick succession of Oligocene volcanic rocks with the existence of one or more paleolakes when the volcanoes were active. The systematic study of the greenschists and associated plutonic and sedimentary rocks in the basal complex of Sierra de Guanajuato has contributed significant information to the concept of accretion of the Guerrero terrane to the SW end of the North American craton in the Early Cretaceous. Research on the Eocene red bed sequence suggests that early extension occurred creating fault patterns that later were reactivated during Neogene Basin and Range pulses. Immediately east of the city of Guanajuato, a thick volcanic sequence is exposed, with two pyroclastic units formed by felsic ignimbrites that almost certainly are related to a nearby caldera, which was active immediately prior to Ag-Au mineralization. The first activity pulse of the caldera produced the Bufa ignimbrite, a massive unit that displays very large thickness variations (300 to <10 m) in short distances, which we interpret as a signal that it may be an intracaldera deposit. The second explosive pulse originated the Calderones formation, a unit formed by an undetermined but large number of ignimbrites, surge deposits, layers with accretionary lapilli, and epiclastic-volcanic deposits. The Calderones formation is characterized by pervasive chloritization, which points out toward the presence of external water in the system, probably related to one or more shallow lakes within the caldera previously formed by the Bufa eruption. Lithofacies variations and stratigraphic arguments suggest that the Guanajuato caldera was probably located near the Cerro Alto de Villalpando and La Peregrina lava dome complex. Morphological and structural evidence of the caldera are masked by several pulses of younger normal faulting which affected the southern portion of the Mexican Basin and Range Province (i.e., Mesa Central).
What is the burden of alcohol-related injuries in an inner city emergency department?
Authors: Hoskins Rebecca , Benger Jonathan
Published: June 2012

Background

The annual cost to the NHS of alcohol-related injury and illness is estimated to be £2.7 billion. Alcohol-related violence has become a concerning public health issue. This study set out to establish the burden of alcohol-related violence in an inner city UK emergency department (ED).

Methods

This single centre study was undertaken in the ED of the Bristol Royal Infirmary. This department serves an inner city population. An independent researcher administered a questionnaire to every patient who attended during the study period. A questionnaire was also administered to the treating clinician to ascertain the diagnosis, and whether the patient's attendance was related to alcohol use.

Results

14% (n=111) of participants felt that their attendance at the ED was related to alcohol. 11% of all injured patients felt it was due to alcohol consumption. 3% of patients attended with an alcohol-related illness. The treating clinicians reported that 21% of all patients in this study attended with a problem either directly or indirectly attributable to alcohol.

Discussion

The number of attendances attributable to alcohol-related injury and illness was at least 14% of all patients. One third of patients presenting with an alcohol-related illness or injury required admission to hospital. If these figures are extrapolated, the number of patients presenting with alcohol-related injury is in excess of 7000 attendances to the Bristol Royal Infirmary annually, or nearly 2 million ED patients every year in England and Wales, resulting in 640 000 admissions.
Overexpression of matrix metalloproteinase-9 is correlated with carotid intraplaque hemorrhage in a swine model
Authors: Jiang Xiao-Bing , Wang Jin-Shan , Liu Dong-Hong , Yuan Wei-Si , Shi Zhong-Song
Published: June 2012

Objective

Carotid intraplaque hemorrhage may result in rapid worsening of stenosis and thrombus formation leading to stroke in patients with carotid atherosclerosis. The purpose of this study was to assess the association of the lesional expression of matrix metalloproteinase (MMP)-9 with carotid plaque and intraplaque hemorrhage in a swine model.

Methods

Carotid atherosclerosis was induced in miniswine using a combination of partial ligation and a high cholesterol diet. The carotid artery and rete mirabile were obtained for histopathological and immunohistochemical studies at 3 months. Atherosclerotic changes were classified by Stary stage according to the American Heart Association and the features of vulnerable carotid plaque were assessed. The association of MMP-9 expression in the carotid plaque with intraplaque hemorrhage was analyzed.

Results

One hundred and ninety-one carotid segments from 10 carotid artery models were assessed. Among 139 segments with atherosclerotic changes, 102 had advanced plaque (Stary stage IV–VI). Atheroemboli were found in all 10 rete mirabili, confirming the presence of vulnerable ipsilateral carotid plaques. There was a trend to increased MMP-9 expression in the group with advanced plaque. Areas positive for MMP-9 were significantly greater in plaques with intraplaque hemorrhage than in those without intraplaque hemorrhage (11.84±1.22% vs 6.63±0.59%, p<0.001).

Conclusions

Increased expression of MMP-9 is associated with intraplaque hemorrhage in a swine model of vulnerable carotid atherosclerosis.
HUMANOID LOCOMOTION PLANNING FOR VISUALLY GUIDED TASKS
Authors: HAYET JEAN-BERNARD , ESTEVES CLAUDIA , ARECHAVALETA GUSTAVO , STASSE OLIVIER , YOSHIDA EIICHI
Published: June 2012

In this work, we propose a landmark-based navigation approach that integrates (1) high-level motion planning capabilities that take into account the landmarks position and visibility and (2) a stack of feasible visual servoing tasks based on footprints to follow. The path planner computes a collision-free path that considers sensory, geometric, and kinematic constraints that are specific to humanoid robots. Based on recent results in movement neuroscience that suggest that most humans exhibit nonholonomic constraints when walking in open spaces, the humanoid steering behavior is modeled as a differential-drive wheeled robot (DDR). The obtained paths are made of geometric primitives that are the shortest in distance in free spaces. The footprints around the path and the positions of the landmarks to which the gaze must be directed are used within a stack-of-tasks (SoT) framework to compute the whole-body motion of the humanoid. We provide some experiments that verify the effectiveness of the proposed strategy on the HRP-2 platform.
Optical Nanoscopy: From Acquisition to Analysis
Authors: Gould Travis J. , Hess Samuel T. , Bewersdorf Joerg
Published: June 2012

Recent advances in far-field microscopy have demonstrated that fluorescence imaging is possible at resolutions well below the long-standing diffraction limit. By exploiting photophysical properties of fluorescent probe molecules, this new class of methods yields a resolving power that is fundamentally diffraction unlimited. Although these methods are becoming more widely used in biological imaging, they must be complemented by suitable data analysis approaches if their potential is to be fully realized. Here we review the basic principles of diffraction-unlimited microscopy and how these principles influence the selection of available algorithms for data analysis. Furthermore, we provide an overview of existing analysis strategies and discuss their application.
Quantitative Imaging Methods for the Development and Validation of Brain Biomechanics Models
Authors: Bayly Philip V. , Clayton Erik H. , Genin Guy M.
Published: June 2012

Rapid deformation of brain tissue in response to head impact or acceleration can lead to numerous pathological changes, both immediate and delayed. Modeling and simulation hold promise for illuminating the mechanisms of traumatic brain injury (TBI) and for developing preventive devices and strategies. However, mathematical models have predictive value only if they satisfy two conditions. First, they must capture the biomechanics of the brain as both a material and a structure, including the mechanics of brain tissue and its interactions with the skull. Second, they must be validated by direct comparison with experimental data. Emerging imaging technologies and recent imaging studies provide important data for these purposes. This review describes these techniques and data, with an emphasis on magnetic resonance imaging approaches. In combination, these imaging tools promise to extend our understanding of brain biomechanics and improve our ability to study TBI in silico.
Sculpting Organs: Mechanical Regulation of Tissue Development
Authors: Nelson Celeste M. , Gleghorn Jason P.
Published: June 2012

The ramified architectures of organs such as the mammary gland and lung are generated via branching morphogenesis, a developmental process through which individual cells bud and pinch off of pre-existing epithelial sheets. Although specified by signaling programs, organ development requires integration of all aspects of the microenvironment. We describe the essential role of endogenous cellular contractility in the formation of branching tubes. We also highlight the role of exogenous forces in normal and aberrant branching.
Microfluidic Models of Vascular Functions
Authors: Wong Keith H.K. , Chan Juliana M. , Kamm Roger D. , Tien Joe
Published: June 2012

In vitro studies of vascular physiology have traditionally relied on cultures of endothelial cells, smooth muscle cells, and pericytes grown on centimeter-scale plates, filters, and flow chambers. The introduction of microfluidic tools has revolutionized the study of vascular physiology by allowing researchers to create physiologically relevant culture models, at the same time greatly reducing the consumption of expensive reagents. By taking advantage of the small dimensions and laminar flow inherent in microfluidic systems, recent studies have created in vitro models that reproduce many features of the in vivo vascular microenvironment with fine spatial and temporal resolution. In this review, we highlight the advantages of microfluidics in four areas: the investigation of hemodynamics on a capillary length scale, the modulation of fluid streams over vascular cells, angiogenesis induced by the exposure of vascular cells to well-defined gradients in growth factors or pressure, and the growth of microvascular networks in biomaterials. Such unique capabilities at the microscale are rapidly advancing the understanding of microcirculatory dynamics, shear responses, and angiogenesis in health and disease as well as the ability to create in vivo–like blood vessels in vitro.
Nonlinear Dynamics in Cardiology
Authors: Krogh-Madsen Trine , Christini David J.
Published: June 2012

The dynamics of many cardiac arrhythmias, as well as the nature of transitions between different heart rhythms, have long been considered evidence of nonlinear phenomena playing a direct role in cardiac arrhythmogenesis. In most types of cardiac disease, the pathology develops slowly and gradually, often over many years. In contrast, arrhythmias often occur suddenly. In nonlinear systems, sudden changes in qualitative dynamics can, counterintuitively, result from a gradual change in a system parameter—this is known as a bifurcation. Here, we review how nonlinearities in cardiac electrophysiology influence normal and abnormal rhythms and how bifurcations change the dynamics. In particular, we focus on the many recent developments in computational modeling at the cellular level that are focused on intracellular calcium dynamics. We discuss two areas where recent experimental and modeling work has suggested the importance of nonlinearities in calcium dynamics: repolarization alternans and pacemaker cell automaticity.
Synthetic Biology: An Emerging Engineering Discipline
Authors: Cheng Allen A. , Lu Timothy K.
Published: June 2012

Over the past decade, synthetic biology has emerged as an engineering discipline for biological systems. Compared with other substrates, biology poses a unique set of engineering challenges resulting from an incomplete understanding of natural biological systems and tools for manipulating them. To address these challenges, synthetic biology is advancing from developing proof-of-concept designs to focusing on core platforms for rational and high-throughput biological engineering. These platforms span the entire biological design cycle, including DNA construction, parts libraries, computational design tools, and interfaces for manipulating and probing synthetic circuits. The development of these enabling technologies requires an engineering mindset to be applied to biology, with an emphasis on generalizable techniques in addition to application-specific designs. This review aims to discuss the progress and challenges in synthetic biology and to illustrate areas where synthetic biology may impact biomedical engineering and human health.
The Effect of Nanoparticle Size, Shape, and Surface Chemistry on Biological Systems
Authors: Albanese Alexandre , Tang Peter S. , Chan Warren C.W.
Published: June 2012

An understanding of the interactions between nanoparticles and biological systems is of significant interest. Studies aimed at correlating the properties of nanomaterials such as size, shape, chemical functionality, surface charge, and composition with biomolecular signaling, biological kinetics, transportation, and toxicity in both cell culture and animal experiments are under way. These fundamental studies will provide a foundation for engineering the next generation of nanoscale devices. Here, we provide rationales for these studies, review the current progress in studies of the interactions of nanomaterials with biological systems, and provide a perspective on the long-term implications of these findings.
The Magnetocaloric Effect and Magnetic Refrigeration Near Room Temperature: Materials and Models
Authors: Franco V. , Blázquez J.S. , Ingale B. , Conde A.
Published: June 2012

In the past 20 years, there has been a surge in research on the magnetocaloric response of materials, due mainly to the possibility of applying this effect for magnetic refrigeration close to room temperature. This review is devoted to the main families of materials suitable for this application and to the procedures proposed to predict their response. Apart from the possible technological applications, we also discuss the use of magnetocaloric characterization to gain fundamental insight into the nature of the underlying phase transition.
Atom Probe Tomography 2012
Authors: Kelly Thomas F. , Larson David J.
Published: June 2012

In the world of tomographic imaging, atom probe tomography (APT) occupies the high-spatial-resolution end of the spectrum. It is highly complementary to electron tomography and is applicable to a wide range of materials. The current state of APT is reviewed. Emphasis is placed on applications and data analysis as they apply to many fields of research and development including metals, semiconductors, ceramics, and organic materials. We also provide a brief review of the history and the instrumentation associated with APT and an assessment of the existing challenges in the field.
Ferroelastic Materials
Authors: Salje Ekhard K.H.
Published: June 2012

Large elastic nonlinearities can lead to elastic hysteresis behavior, which defines ferroelasticity in analogy to its sister ferroics: ferromagnetism and ferroelectricity. Ferroelasticity is the most common nonlinear effect in natural materials and plays a major role in the mineralogical behavior of the Earth's crust and mantle. It produces interfacial twin walls that act as sinks and sources for defects and that show localized effects such as superconducting twin boundaries and ferroelectricity, even when such effects do not exist in the bulk. The movement of twin walls under elastic forcing is creep-like, with some superimposed jerks due to pinning and unpinning by defects and jamming by other twin boundaries. This review applies Landau theory and discusses some aspects of the emerging field of domain boundary engineering.
Measurement of Interfacial Evolution in Three Dimensions
Authors: Rowenhorst D.J. , Voorhees P.W.
Published: June 2012

The experimental measurement of the evolution of interfaces in three dimensions is reviewed, concentrating on the evolution of polycrystalline and solid-liquid systems, including growth and coarsening in dendritic systems and evolution during liquid-phase sintering. Both ex situ destructive techniques and in situ nondestructive techniques are considered. The importance of making three-dimensional measurements that can be quantified and unambiguously compared with theory is discussed, showing that these measurements provide a direct validation of theory and critical initial conditions for simulations.
Solid-State Dewetting of Thin Films
Authors: Thompson Carl V.
Published: June 2012

Solid films are usually metastable or unstable in the as-deposited state, and they will dewet or agglomerate to form islands when heated to sufficiently high temperatures. This process is driven by surface energy minimization and can occur via surface diffusion well below a film's melting temperature, especially when the film is very thin. Dewetting during processing of films for use in micro- and nanosystems is often undesirable, and means of avoiding dewetting are important in this context. However, dewetting can also be useful in making arrays of nanoscale particles for electronic and photonic devices and for catalyzing growth of nanotubes and nanowires. Templating of dewetting using patterned surface topography or prepatterning of films can be used to create ordered arrays of particles and complex patterns of partially dewetted structures. Studies of dewetting can also provide fundamental new insight into the effects of surface energy anisotropy and facets on shape evolution.
Fatigue and Damage in Structural Materials Studied by X-Ray Tomography
Authors: Withers Philip J. , Preuss Michael
Published: June 2012

This paper reviews progress using X-ray computed tomography to study damage accumulation. Since its introduction, X-ray microtomography has been used to diagnose the presence of damage. In this review, a wide range of damage-accumulation mechanisms are covered including cavitation, fracture, microcracking, fatigue cracking, and stress corrosion cracking. In this regard, the advantages of attenuation and phase contrast imaging are discussed. This review includes both measurements of damage accumulation, taken postmortem, and the incremental monitoring of damage-accumulation processes during life (sometimes termed four-dimensional tomography). In addition to the qualitative diagnostic studies, the quantitative analysis of tomography images to extract key failure parameters is examined.
Mechanisms of Inflammatory Responses in Obese Adipose Tissue
Authors: Sun Shengyi , Ji Yewei , Kersten Sander , Qi Ling
Published: June 2012

The fields of immunology and metabolism are rapidly converging on adipose tissue. During obesity, many immune cells infiltrate or populate in adipose tissue and promote a low-grade chronic inflammation. Studies to date have suggested that perturbation of inflammation is critically linked to nutrient metabolic pathways and to obesity-associated complications such as insulin resistance and type 2 diabetes. Despite these advances, however, many open questions remain including how inflammatory responses are initiated and maintained, how nutrients impact the function of various immune populations, and how inflammatory responses affect systemic insulin sensitivity. Here we review recent studies on the roles of various immune cells at different phases of obesity and discuss molecular mechanisms underlying obesity-associated inflammation. Better understanding of the events occurring in adipose tissue will provide insights into the pathophysiological role of inflammation in obesity and shed light on the pathogenesis of obesity-associated metabolic syndrome.
Hypomagnesemia and Inflammation: Clinical and Basic Aspects
Authors: Weglicki William B.
Published: June 2012

In recent years, increasing awareness of hypomagnesemia has resulted in clinical trials that associate this mineral deficiency with diabetes, metabolic syndrome, and drug therapies for cancer and cardiovascular diseases. However, diagnostic testing for tissue deficiency of magnesium still presents a challenge. Investigations of animal and cellular responses to magnesium deficiency have found evidence of complex proinflammatory pathways that may lead to greater understanding of mediators of the pathobiology in neuronal, cardiovascular, intestinal, renal, and hematological tissues. The roles of free radicals, cytokines, neuropeptides, endotoxin, endogenous antioxidants, and vascular permeability, and interventions to limit the inflammatory response associated with these parameters, are outlined in basic studies of magnesium deficiency. It is hoped that this limited review of inflammation associated with some diseases complicated by magnesium deficiency will prompt greater awareness by clinicians and other health providers and in turn increase efforts to prevent and treat this disorder.
Lessons Learned from Randomized Clinical Trials of Micronutrient Supplementation for Cancer Prevention
Authors: Mayne Susan T. , Ferrucci Leah M. , Cartmel Brenda
Published: June 2012

This review discusses the results of randomized clinical trials of supplemental micronutrients for cancer prevention completed over the past 20 years, including trials of beta-carotene and retinol, vitamins C and E, selenium, folic acid, and vitamin D. Some trials observed significant reductions in risk, whereas others observed significant increases in risk of the primary cancer endpoint. In considering these trials, it appears that supplementation targeted to populations with low status of the nutrient of interest may prevent cancer, whereas supplementation in populations with higher status or to achieve pharmacological exposures may promote cancer. Observational epidemiologic evidence coupled with these trial results supports the concept of a U-shaped curve for micronutrients in relation to cancer prevention. Based on these data, nutrient supplements are not currently recommended for cancer prevention in the general population. The hypothesis that groups with low nutrient status may benefit from supplementation has yet to be formally tested.