bluuebunny/crossref_metadata_2025 huggingface dataset:
Membrane Vesicle Release in Bacteria, Eukaryotes, and Archaea: a Conserved yet Underappreciated Aspect of Microbial Life
Authors: Deatherage Brooke L. , Cookson Brad T.
Published: March 2012

Interaction of microbes with their environment depends on features of the dynamic microbial surface throughout cell growth and division. Surface modifications, whether used to acquire nutrients, defend against other microbes, or resist the pressures of a host immune system, facilitate adaptation to unique surroundings. The release of bioactive membrane vesicles (MVs) from the cell surface is conserved across microbial life, in bacteria, archaea, fungi, and parasites. MV production occurs not only
in vitro
but also
in vivo
during infection, underscoring the influence of these surface organelles in microbial physiology and pathogenesis through delivery of enzymes, toxins, communication signals, and antigens recognized by the innate and adaptive immune systems. Derived from a variety of organisms that span kingdoms of life and called by several names (membrane vesicles, outer membrane vesicles [OMVs], exosomes, shedding microvesicles, etc.), the conserved functions and mechanistic strategies of MV release are similar, including the use of ESCRT proteins and ESCRT protein homologues to facilitate these processes in archaea and eukaryotic microbes. Although forms of MV release by different organisms share similar visual, mechanistic, and functional features, there has been little comparison across microbial life. This underappreciated conservation of vesicle release, and the resulting functional impact throughout the tree of life, explored in this review, stresses the importance of vesicle-mediated processes throughout biology.
How well informed are patients when leaving the emergency department? comparing information provided and information retained
Authors: Marty Hans , Bogenstätter Yvonne , Franc Gabriela , Tschan Franziska , Zimmermann Heinz
Published: March 2012

Study objective

Patients discharged from the emergency department (ED) should be informed comprehensively and accurately about the diagnosis, future examinations and follow-up care. This study investigates: (1) how comprehensively patients are informed by physicians on discharge; (2) how accurately patients remember this information after discharge; (3) how well informed overall patients leave the ED; and (4) whether informedness relates to patient satisfaction.

Methods

This study compares: (1) information given during discharge conversations, based on audio recordings of the conversations, with (2) accuracy of patient recall of this information, based on postdischarge interviews. During these interviews, the authors also assessed (3) amount and accuracy of information provided during treatment. Furthermore, the authors obtained (4) satisfaction ratings by physicians and patients. Data were collected for 96 patients during 20 shifts.

Results

Sufficient information was provided in 83% of discharge conversations. Patients correctly recalled 82% of information received about diagnosis, 56% about examinations planned and 72% about follow-up treatments. Information related to medication was most prone to forgetting or distortion. Altogether, 43% of the patients left the ED correctly informed about diagnosis, planned examinations and follow-up. Patient satisfaction ratings were high (mean 4.7 on a 5-point Likert Scale) and not related to informedness of the patient.

Conclusions

Patients had important information deficits when leaving the ED, and information transmission needs to be improved. The physician–patient discharge conversation seems an ideal opportunity for enhancing patient informedness. Standardisation of discharge procedures and training physicians in how to ensure that patients actually understand the information provided are needed.
Nose and vein, speed and pain: comparing the use of intranasal diamorphine and intravenous morphine in a Scottish paediatric emergency department
Authors: Regan Luke , Chapman Andrew R , Celnik Anna , Lumsden Lesley , Al-Soufi Reem , McCullough Nicola P
Published: March 2012

Background

Urgent analgesia is essential for all children who present in severe pain, but difficulties in obtaining venous access can delay the use of adequate opiate analgesia. Intranasal diamorphine (IND) is now in use in around 60% of emergency departments and is the preferred choice of analgesia as reported by both parents and healthcare professionals. While IND has similar efficacy to intramuscular morphine in children, no study has compared its use against the current gold standard, intravenous morphine (IVM).

Methods

IND was introduced to the Royal Aberdeen Children's Hospital on 24 December 2009. A retrospective case series was constructed to compare its clinical performance with its predecessor IVM. Three unexplored factors were investigated: time to opiate analgesia, the requirement for further analgesia when still in the emergency department and the effect of simple coanalgesia (eg, paracetamol/ibuprofen) on these requirements.

Results

297 patients were eligible for the study (147 IND, 150 IVM) over a 28-month period. There was a non-significant trend to a longer median time to administration of analgesia in patients receiving IND (p=0.170). Patients who received IND were less likely to require further analgesia (p<0.001). Both groups were less likely to require further analgesia when simple coanalgesia was given (p=0.049).

Conclusion

The authors found no significant difference in time to administration of analgesia between agents, but a learning curve has been identified. Sustained effort should be placed on the use of simple coanalgesia. The clinical performance of IND compares favourably with IVM in children with severe pain, and it remains an appropriate preferred agent.
Comments on the dilemma in the February issue: ‘Shortcomings in locum practice procedures’
Authors: Mullan Siobhan
Published: March 2012

The dilemma in the February issue questioned what you should do if you disagreed with practice procedures while working as a locum (In Practice, February 2012, volume 34, pages 110–111). In the example discussed, a client asked for a repeat prescription for acepromazine tablets for a dog in the run up to bonfire night. You knew that it was not the ideal treatment from a behavioural point of view, but other clients' records showed that acepromazine was widely prescribed by the practice for firework phobias. Richard Green commented that locum vets had obligations to the animal, client, practice, colleagues and themselves, and that it was useful to use an ethical matrix to allow due consideration of each of these stakeholders' interests. It was inevitable that there would be differences of opinion on how to do things between the locum and the practice, but very few of these would impact on patient welfare. In instances where the practice was falling short of best practice, locums could use their influence to change things for the better. Many practices were willing to change but did not do so because of inertia or lack of awareness. Best practice changed all the time, and it should be possible to tactfully discuss alternative treatments to the customary ones without overtly criticising colleagues.
Clinical audit: a tool in the defence of clinical standards
Authors: Dunn James
Published: March 2012

James Dunn outlines the process of clinical audit, arguing that regular clinical audit, at local level, empowers clinicians, improves patient care and provides robust grounds for defence against complaints. In a second article, to be published in the April issue of In Practice, he will use antimicrobial prescription as an example to illustrate the application of clinical audit in veterinary practice.
Wnt signalling pathway in the serrated neoplastic pathway of the colorectum: possible roles and epigenetic regulatory mechanisms
Authors: Fu Xiangsheng , Li Li , Peng Yan
Published: March 2012

The role of Wnt signalling in the serrated neoplastic pathway of colorectal tumourigenesis appears to be heterogeneous. Wnt pathway abnormalities contribute to the progression of at least a subset of traditional serrated adenomas of the colorectum, but may play a less active role in its pathogenesis compared with that in conventional adenoma-carcinoma. However, immunohistochemical studies of β-catenin in sessile serrated adenomas have shown wide variability, producing conflicting results on Wnt signalling activation in sessile serrated adenomas. DNA methylation, involvingAPC,SFRPs and mutated in colorectal cancer (MCC), may bridge the mutational gap ofAPCorβ-cateninfor activating Wnt signalling in serrated adenomas of the colorectum.
Adjunctive use of eptifibatide for complication management during elective neuroendovascular procedures
Authors: Dumont Travis M , Kan Peter , Snyder Kenneth V , Hopkins L Nelson , Siddiqui Adnan H , Levy Elad I
Published: March 2012

Objective

A rare complication of neuroendovascular procedures is acute thromboembolism. In the setting of intraprocedural or periprocedural embolism, thrombolytics present a potentially useful therapeutic strategy. A series of patients in whom eptifibatide (a platelet glycoprotein IIb/IIIa receptor inhibitor) was used in the treatment of iatrogenic thromboembolic events occurring during elective neuroendovascular procedures is described.

Methods

Consecutive cases between May 2009 and July 2011 in which eptifibatide was administered were identified and individually reviewed for inclusion in this study (n=12). All study patients received a uniform, weight based bolus dose of 180 μg/kg of eptifibatide administered either intra-arterially through the guide catheter or intravenously. Eptifibatide infusion (2 μg/kg/min) for 24 h after bolus dose administration was continued at the discretion of the surgeon. Procedural details are described and illustrative cases presented.

Results

Three major categories of thromboembolic events were isolated in the course of review of study cases: acute focal neurological decline and no radiographic findings of flow limitation (eight patients), radiographic findings with or without symptoms (two patients) and persistent particulate debris during flow reversal as part of a carotid revascularization procedure (two patients). Following eptifibatide administration, no patient experienced hemorrhagic complications, and neurologic improvement to baseline level was noted in 10 of 12 patients.

Conclusion

Eptifibatide may be an effective therapeutic strategy in the event of thromboembolism during elective neuroendovascular procedures.
Effect of Tai Chi on Body Balance: Randomized Controlled Trial in Elderly Men with Dizziness
Authors: Maciaszek Janusz , Osinski Wieslaw
Published: March 2012

The purpose of this study was to assess the effect of 18-week Tai Chi training on body balance in a dynamic trial among elderly men with dizziness. The study covered subjects aged 60 to 80 years. We identified 40 men who reported a history of dizziness. The subjects were recruited using direct mailings and a community information campaign. The participants were randomly assigned to either the exercise intervention (n = 20) or control group (n = 20). The Tai Chi group participated in an 18-week exercise class held for 45 minutes twice a week. Body balance was studied in two ways: using the "8 foot up and go test" (Rikli and Jones 2001) and using a Computer Posturographic System PE 90 (manufactured by Military Institute of Aviation Medicine in Warsaw and outfitted with Pro-Med modified software). The ability to perform specific tasks (maximal deflections in four directions) was measured on the posturographic platform. The variation in results obtained on the first and second date of tests in the experimental and control groups was confirmed statistically using four parameters, i.e. "8 foot up to and go test ( H = 8.21;p = 0.003), forward deflection ( H = 3.70;p = 0.050), backward deflection ( H = 5.04;p = 0.024) and maximum sway area ( H = 8.86;p = 0.002). Consequently, we found that the 18-week period of Tai-Chi exercises, with a frequency of twice a week for 45 minutes, is beneficial for dynamic balance, which is important for the reduction of fall risk factors among elderly men with dizziness.
Preventive Effects of β-Thujaplicin Against UVB-Induced MMP-1 and MMP-3 mRNA Expressions in Skin Fibroblasts
Authors: Cherng Jong Yuh , Chen Li Yin , Shih Mei Fen
Published: March 2012

Solar UV radiation damages human skin by affecting skin tone and resiliency and leads to premature aging (photoaging). The skin damage is caused by the activation of the AP-1 transcription factor, which increases matrix metalloproteinase (MMP) expression and collagen degradation. An increase of interleukin (IL)-6 is also correlated with the activation of MMP-1 expression. β-thujaplicin has shown both acaricidal and antimicrobial activities. Also, β-thujaplicin has been shown to be protective against apoptosis due to the oxidative effects of UV irradiation. However, the effect of β-thujaplicin on UVB-induced MMPs had not been investigated. In this study, after UVB exposure, MMP-1 and IL-6 production in human skin fibroblasts was examined in the presence of β-thujaplicin, vitamin C, and vitamin E. The expression of MMP-1, MMP-3, tissue inhibitor of metalloproteinase (TIMP-1, TIMP-3) and procollagen mRNA was also investigated. Results showed that UVB-induced MMP-1 production was suppressed by the β-thujaplicin treatment in a dose-dependent manner, but not by vitamin C and vitamin E. β-thujaplicin also prevented the up-regulation of MMP-1 and MMP-3 mRNA. Moreover, the UVB-suppressed procollagen gene expression was restored to normal by β-thujaplicin. Neither UVB nor β-thujaplicin affected the mRNA expression of TIMP-1 and TIMP-3. The IL-6 production induced by UVB was lower in β-thujaplicin treated fibroblasts than in the controls. In conclusion, this study shows the capability of β-thujaplicin in preventing MMP-1 production due to UVB irradiation via inhibition of MMP gene expression. Importantly, the UVB-suppressed procollagen gene expression can be restored to normal by β-thujaplicin. These findings indicate that β-thujaplicin is a promising and potent agent to inhibit UVB-induced MMP-1 and MMP-3 gene expression in skin fibroblasts.
MUON CAPTURE ON DEUTERON AND 3He: A PERSONAL REVIEW
Authors: MARCUCCI LAURA ELISA
Published: March 2012

The present status of theoretical and experimental studies of muon capture reactions on light nuclei is reviewed. In particular, the recent results for the two reactions 2 H (μ-,νμ)nn and 3 He (μ-, νμ)3 H are presented, and the unresolved discrepancies among different measurements and calculations, open problems, and future developments are discussed.
TOWARDS THE LOCALIZATION OF SUSY GAUGE THEORY ON A CURVED SPACE
Authors: NAGASAKI KOICHI , YAMAGUCHI SATOSHI
Published: March 2012

We consider an [Formula: see text] supersymmetric gauge theory on a curved space. We try to generalize Pestun's localization calculation on the four-sphere to a more general class of curved spaces. We calculated the Q-exact term to localize the path-integral, and when it becomes positive-definite, we obtain a configuration where the path-integral localizes. We also evaluate the super-Yang–Mills action in this configuration.
FORESTS OF PROBABILITY ESTIMATION TREES
Authors: BOSTRÖM HENRIK
Published: March 2012

Probability estimation trees (PETs) generalize classification trees in that they assign class probability distributions instead of class labels to examples that are to be classified. This property has been demonstrated to allow PETs to outperform classification trees with respect to ranking performance, as measured by the area under the ROC curve (AUC). It has further been shown that the use of probability correction improves the performance of PETs. This has lead to the use of probability correction also in forests of PETs. However, it was recently observed that probability correction may in fact deteriorate performance of forests of PETs. A more detailed study of the phenomenon is presented and the reasons behind this observation are analyzed. An empirical investigation is presented, comparing forests of classification trees to forests of both corrected and uncorrected PETS on 34 data sets from the UCI repository. The experiment shows that a small forest (10 trees) of probability corrected PETs gives a higher AUC than a similar-sized forest of classification trees, hence providing evidence in favor of using forests of probability corrected PETs. However, the picture changes when increasing the forest size, as the AUC is no longer improved by probability correction. For accuracy and squared error of predicted class probabilities (Brier score), probability correction even leads to a negative effect. An analysis of the mean squared error of the trees in the forests and their variance, shows that although probability correction results in trees that are more correct on average, the variance is reduced at the same time, leading to an overall loss of performance for larger forests. The main conclusions are that probability correction should only be employed in small forests of PETs, and that for larger forests, classification trees and PETs are equally good alternatives.
POWER LAWS AND OTHER HEAVY-TAILED DISTRIBUTIONS IN LINGUISTIC TYPOLOGY
Authors: JÄGER GERHARD
Published: March 2012

The paper investigates the quantitative distribution of language types across languages of the world. The studies are based on three large-scale typological data bases: The World Color Survey, the Automated Similarity Judgment Project data base, and the World Atlas of Language Structures. The main finding is that a surprisingly large and varied collection of linguistic typologies show power law behavior. The bulk of the paper deals with the statistical validation of these findings.
AN EXPERIMENTAL APPROACH TO SPEAKERS' PERSPECTIVES IN A PAIRED WALL GAME
Authors: UNO RYOKO , SUZUKI KEISUKE , IKEGAMI TAKASHI
Published: March 2012

A new interactive "wall game" is proposed to study the emergence of rules and symbols in interaction dynamics. In this game, two human players alternately configure a pattern on a board to communicate with each other. Distinct from related studies, players in this game have no explicit game scores or tasks to optimize. Any dynamics occurring in this game are therefore ad-hoc and on-going processes. There were three major findings in this paper. (i) The subjects mainly interacted in two modes: a dynamic mode where players proceed through the game without assigning any meanings to the pattern, and a metaphoric mode, where players process with narrative reflection. (ii) Subjects spontaneously switch between the two modes, but this switching is suppressed when playing alone. (iii) A transition diagram of the board pattern can be used to label the two modes, e.g. linearity of the diagram is correlated with the metaphoric mode. One of the main features of grammar is to display subjects' intentionality in a systematic way. We argue that the switching between the two modes observed in our experiment can be taken as a grammatical aspect that emerged in the process. These modes express the speaker's perspective in the same manner as grammatical elements do in natural language. The switching behavior should be seen as a process that embodies a player's intention using the medium (in this case, the patterns in the wall game), and a player's exploration of the medium is a necessary step before generating a grammar structure.
LANGUAGE DYNAMICS IN STRUCTURED FORM AND MEANING SPACES
Authors: DE BOER BART , VERHOEF TESSA
Published: March 2012

This paper reviews how the structure of form and meaning spaces influences the nature and the dynamics of the form-meaning mappings in language. In general, in a structured form or meaning space, not all forms and meanings are equivalent: some forms and some meanings are more easily confused with each other than with other forms or meanings. We first give a formalization of this idea, and explore how it influences robust form-meaning mappings. It is shown that some fundamental properties of human language, such as discreteness and combinatorial structure as well as universals of sound systems of human languages follow from optimal communication in structured form and meaning spaces. We also argue that some properties of human language follow less from these fundamental issues, and more from cognitive constraints.

We then show that it is possible to experimentally investigate the relative contribution of functional constraints and of cognitive constraints. We illustrate this with an example of one of our own experiments, in which experimental participants have to learn a set of complex form-meaning mappings that have been produced by a previous generation of participants. Theoretically predicted properties appear in the sets of signals that emerge in this iterated learning experiment.
In defense of doing it the hard way
Authors: Gingras Leanna
Published: March 2012

Evaluation and usability as a practice area has diversified its approaches, broadened the spectrum of UX issues it addresses, and extended its contribution into deeper levels of product-development decision making. This forum addresses conceptual, methodological, and professional issues that arise in the field's continuing effort to contribute robust information about users to product planning and design.

David Siegel and Susan Dray, Editors
Correct router interface modeling (abstracts only)
Authors: Rusek Krzysztof , Janowski Lucjan , Papir ZdzisBaw
Published: March 2012

The aim of this paper is to determine how to model router interface in order to accurately predict packet drops. There is an enormous amount of research on traffic models reported, however, a model of router interface has not gained proper consideration yet.

Our experiments reveal that an incorrect model of the router interface can result in a significant disparity between drop probabilities measured on a physical interface and derived from a trace-driven simulation study. In this paper an accurate model of the router interface (Cisco IOS-based routers with a non-distributed architecture) was presented.
A PMIF with Petri net building blocks (abstracts only)
Authors: Lladó Catalina M. , Harrison Peter G.
Published: March 2012

Performance model interchange formats (PMIFs) support the portability of models and sharing of solutions amongst different tools. XML-based interchange formats have been defined for the interchange of queueing network and Petri net models, amongst others, but there is still scope to extend their application to multiple formalisms, in particular beyond queueing networks. We extend an existing PMIF to hybrid models by including a new type of node, called a "building block", defined as a certain class of Petri nets. The synchronisation primitives of these building blocks can be used to specify fork-join systems whilst, under certain conditions, retaining product-form solutions when embedded in queueing (or other) networks possessing this property already. When a product-form does not exist, the whole network is translated into a Petri net and solved either by simulation or direct solution of the underlying Markov chain by an existing analyser. Finally, we apply the extended PMIF to model a computer system with RAID storage.
Integrated estimation and tracking of performance model parameters with autoregressive trends (abstracts only)
Authors: Zheng Tao , Litoiu Marin , Woodside Murray
Published: March 2012

Adaptive management of a software service system can take advantage of a performance model which can predict the effect of proposed changes, before they are deployed. As the system varies over time the model parameters can be tracked by an estimator such as a Kalman Filter, so that decisions can be updated. The filter is valuable when parameters are "hidden" and cannot be directly measured without excessive cost (as is usually the case for the CPU time of a service). Because there may be significant delays in some management control actions (especially in deploying a new replica of a service), it is also important to be able to predict the changes ahead somewhat in time, that is, to predict the trends. The trend predictor itself needs to be estimated from observed trends in the model parameters. This work uses an autoregressive model for trend prediction and integrates it with the parameter estimator, in a single Kalman Filter, using auxiliary states for the parameter evolution process. This paper describes how the trend model is constructed, and evaluates its effectiveness. It compares the overall performance predictions to a simpler trend predictor using linear extrapolation of the fitted parameter time-series, which turns out to be almost as good. The approach is validated on a real system running a benchmark web application.
Dynamic selection of implementation variants of sequential iterated runge-kutta methods with tile size sampling (abstracts only)
Authors: Kalinnik Natalia , Korch Matthias , Rauber Thomas
Published: March 2012

This paper describes an efficient self-adaptive procedure for iterated Runge-Kutta (IRK) methods, a class of solution methods for initial value problems (IVPs) of ordinary differential equations (ODEs). IRK methods execute a potentially large number of discrete time steps to compute the solution of the IVP. The performance of an IRK solver may strongly depend on the specific characteristics of the given IVP and the hardware architecture on which the solver is executed. To address this problem, this paper applies dynamic auto-tuning to the sequential execution of IRK methods. Auto-tuning is a promising technique to avoid time consuming and extensive manual tuning. Our self-adaptive IRK solver utilizes the time-stepping nature of the IRK method. It selects the fastest implementation variant for the given IVP on the target architecture from a candidate pool during the first time steps. Then, the fastest implementation variant is used to compute all remaining time steps. The different implementation variants in the candidate pool have been developed by modifications of the loop structure of the basic algorithm. For those implementation variants that use loop tiling, we consider different tile sizes during the autotuning phase to further improve the performance of the selfadaptive IRK solver. Runtime experiments demonstrate the efficiency of the self-adaptive IRK solver for different IVPs on different hardware architectures.
Power and energy-aware processor scheduling (abstracts only)
Authors: Brochard Luigi , Panda Raj , DeSota Don , Thomas Francois , Bell Robert H.
Published: March 2012

Power consumption is a critical consideration in high computing systems. We propose a novel job scheduler that optimizes power and energy consumed by clusters when running parallel benchmarks with minimal impact on performance. We construct accurate models for estimating power consumption. These models are based on measurements of power consumption on benchmarks with different characteristics and on systems with processors using different microarchitectures. We show the power estimation models achieve less than 2% error versus actual measurements. We show a job scheduler can be enhanced to make it "power-aware" and to optimize power consumption of jobs with similar performance characteristics. The enhanced scheduler can estimate the power consumed by a particular job using the power estimation model, configure the nodes in the cluster via suitably adjusting processor frequency on each of the nodes to maximize performance, minimize power, or minimize energy with a predictable impact on power, energy and performance.
IO performance prediction in consolidated virtualized environments (abstracts only)
Authors: Kraft Stephan , Casale Giuliano , Krishnamurthy Diwakar , Greer Des , Kilpatrick Peter
Published: March 2012

We propose a trace-driven approach to predict the performance degradation of disk request response times due to storage device contention in consolidated virtualized environments. Our performance model evaluates a queueing network with fair share scheduling using trace-driven simulation. The model parameters can be deduced from measurements obtained inside Virtual Machines (VMs) from a system where a single VM accesses a remote storage server. The parameterized model can then be used to predict the effect of storage contention when multiple VMs are consolidated on the same virtualized server. The model parameter estimation relies on a search technique that tries to estimate the splitting and merging of blocks at the the Virtual Machine Monitor (VMM) level in the case of multiple competing VMs. Simulation experiments based on traces of the Postmark and FFSB disk benchmarks show that our model is able to accurately predict the impact of workload consolidation on VM disk IO response times.
Dynamic VM migration
Authors: Srinivasan Krishnamurthy , Yuuw Sterlan , Adelmeyer Tom J.
Published: March 2012

Dynamic migration of virtual machines (VMs) across physical servers has the potential to increase the utilization of the servers and hence drive down the data center costs. However, IT practitioners are leery of using this capability for increasing resource utilization due to concerns about the impact of such migrations on the performance of the applications, particularly the response times seen by the users of the applications. The relative newness to the industry of many of the tools used to automate VM migrations for resource utilization; data from researchers; as well as the recommendations from some analysts justify such caution and warrant quantifying the risks as well as potential rewards before deciding how aggressively this capability should be adopted. This paper will discuss the requirements for a benchmark to be used for such quantification. We will also discuss adaptations to SPECvirt sc2010, originally developed as a single server benchmark, to meet these requirements. We will also present risk-reward quantifications obtained using this benchmark for a simple case and the broader use of the benchmark for other cases.
Workload characterization of cryptography algorithms for hardware acceleration (abstracts only)
Authors: Chang Jed Kao-Tung , Liu Chen , Liu Shaoshan , Gaudiot Jean-Luc
Published: March 2012

Data encryption/decryption has become an essential component for modern information exchange. However, executing these cryptographic algorithms is often associated with huge overhead and the need to reduce this overhead arises correspondingly. In this paper, we select nine widely adopted cryptography algorithms and study their workload characteristics. Different from many previous works, we consider the overhead not only from the perspective of computation but also focusing on the memory access pattern. We break down the function execution time to identify the software bottleneck suitable for hardware acceleration. Then we categorize the operations needed by these algorithms. In particular, we introduce a concept called "Load-Store Block" (LSB) and perform LSB identification of various algorithms. Our results illustrate that for cryptographic algorithms, the execution rate of most hotspot functions is more than 60%; memory access instruction ratio is mostly more than 60%; and LSB instructions account for more than 30% for selected benchmarks. Based on our findings, we suggest future directions in designing either the hardware accelerator associated with microprocessor or specific microprocessor for cryptography applications.
Characterization, monitoring and evaluation of operational performance trends on server processor hardware (abstracts only)
Authors: Sithole Ernest , McClean Sally , Scotney Bryan , Parr Gerard , Moore Adrian , Dawson Stephen
Published: March 2012

Enterprise IT environments have seen a sharp growth in content use due to the popularity of on-demand data-intensive applications. In turn, the huge demand in content has spawned off major developments such as growth and distribution of computing nodes as well as the adoption of various implementation technologies. Given the complexity brought to the makeup of business computing environments in addressing the above-mentioned factors, the critical planning task of determining the appropriate infrastructure sizes for supporting firm Quality of Service (QoS) guarantees becomes a very challenging undertaking to fulfil. Benchmarking methods are widely employed in calibrating attainable performance in IT solutions, but these have the drawback of presenting output performance metrics as composite measurements that only give an end-to-end perspective. As an enhancement to benchmarking approaches, we explore the use of Performance Monitoring Counters (PMCs) in obtaining detailed operational performance of CPU and memory hardware. Performance Monitoring Counters (PMCs) are onchip registers found on most modern processor hardware. We use PMC-derived measurements to validate cache performance trends that have been derived analytically, and in the course of validations, PMC data is also used to investigate the nature and character of surges in cache miss events, which emerge as the memory load generated by runtime processes increases.
Powering down for energy efficient peer-to-peer file distribution
Authors: Sucevic Andrew , Andrew Lachlan L.H. , Nguyen Thuy T.T.
Published: March 2012

Peer to peer (P2P) techniques can reduce the time for file distribution, yet require peers to stay ON to assist others download. We study the total time that peers need to be ON to distribute a file from a server to a set of peers. We show that a P2P system optimized for energy effciency can consume half the energy of one optimized to minimize download time, with minimal additional delay. To achieve this, peers finish in increasing order of upload capacity and behave selfishly, turning off as soon as they finish downloading. We show that the optimal solution is complex, even for as few as three peers, and advocate heuristics for large networks.
Improving performance and energy savings through alternative forwarding
Authors: Lee Yong Oh
Published: March 2012

Reducing energy consumption in networks is receiving considerable research interest. Different approaches have been advocated, from traffic engineering and topology control to hardware-based approaches. These approaches can work at long-time scales of several hours to very small timescales of a few microseconds.

In this paper, we focus on finer time granularity energy saving schemes. To increase the usage of active links and to increase the down time of already sleeping links, we use alternative forwarding. To our best knowledge, this is the first attempt to collaborate a routing scheme with hardware scheme to save energy consumption in the wired networks. In our evaluation, alternative forwarding achieves 10% more energy saving of the communication links compared to a hardware-based sleeping scheme.
Thread scheduling for heterogeneous multicore processors using phase identification
Authors: Sawalha Lina , Tull Monte P. , Barnes Ronald D.
Published: March 2012

Heterogeneous multicore processors (HMPs) offer promise for significant efficiency improvement. Power-effcient cores can be paired with higher performance cores in an HMP to achieve a beneficial design in terms of both power and performance. However, such processors produce challenges in the effective mapping of threads to cores. An application could have very different behavior and performance when executing on cores of different types. The behavior of typical applications also vary with their phases of execution. Thus, the type of core providing the best performance for an application may depend on the current phase. In this work, we highlight the correlation between execution phases of an application and the performance of those phases on particular core types. We propose mechanisms that identify program phases, exploit the performance behavior of these phases to make effective scheduling decisions, and reuse the result of these scheduling decisions on future occurrences of the same program phases.
Technology Review of Modern Gas Turbine Inlet Filtration Systems
Authors: Wilcox Melissa , Kurz Rainer , Brun Klaus
Published: March 2012

An inlet air filtration system is essential for the successful operation of a gas turbine. The filtration system protects the gas turbine from harmful debris in the ambient air, which can lead to issues such as FOD, erosion, fouling, and corrosion. These issues if not addressed will result in a shorter operational life and reduced performance of the gas turbine. Modern day filtration systems are comprised of multiple filtration stages. Each stage is selected based on the local operating environment and the performance goals for the gas turbine. Selection of these systems can be a challenging task. This paper provides a review of the considerations for selecting an inlet filtration system by covering (1) the characteristics of filters and filter systems, (2) a review of the many types of filters, (3) a detailed look at the different environments where the gas turbine can operate, (4) a process for evaluating the site where the gas turbine will be or is installed, and (5) a method to compare various filter system options with life cycle cost analysis.
Effect of Carbon Nanotube Aqueous Dispersion Quality on Mechanical Properties of Cement Composite
Authors: Nasibulina Larisa I. , Anoshkin Ilya V. , Nasibulin Albert G. , Cwirzen Andrzej , Penttala Vesa , Kauppinen Esko I.
Published: March 2012

An effect of the quality of carbon nanotube (CNT) dispersions added to cement on paste mechanical properties has been studied. High‐quality dispersions of few‐walled CNT (FWCNTs) were produced in two steps. First, FWCNTs were functionalized in a mixture of nitric and sulfuric acids (70 wt.% and 96 wt.%, resp.) at 80∘C. Second, functionalized FWCNTs were washed out by acetone to remove carboxylated carbonaceous fragments (CCFs) formed during CNT oxidation. Mechanical test results showed 2‐fold increase in the compressive strength of the cement paste prepared from the dispersion of acetone‐washed functionalized FWCNTs, which is believed to occur due to the chemical interaction between cement matrix and functional groups (–COOH and –OH). Utilisation of unwashed FWCNTs led to a marginal improvement of mechanical properties of the cement pastes, whereas surfactant‐treated functionalized FWCNT dispersions only worsened the mechanical properties.
Electrical and Thermal Behavior of Copper‐Epoxy Nanocomposites Prepared via Aqueous to Organic Phase Transfer Technique
Authors: Mohd Hirmizi N. H. , Abu Bakar M. , Tan W. L. , Abu Bakar N. H. H. , Ismail J. , See C. H.
Published: March 2012

The preparation, electrical, and thermal behaviors of copper‐epoxy nanocomposites are described. Cetyltrimethylammonium bromide‐ (CTAB‐) stabilized copper (Cu) particles were synthesized via phase transfer technique. Isopropanol (IPA), sodium borohydride (NaBH4), and toluene solution of diglycidyl ether of bisphenol A (DGEBA) were used as transferring, reducing agent, and the organic phase, respectively. The UV‐Vis absorbance spectra of all the sols prepared indicate that the presence of Cu particles with the particles transfer efficiency is ≥97%. The amount, size, and size distribution of particles in the organosol were dependent on the content of organic solute in the organosol. The composites were obtained upon drying the organosols and these were then subjected to further studies on the curing, thermal, and electrical characteristic. The presence of Cu fillers does not significantly affect the completeness of the composite curing process and only slightly reduce the thermal stability of the composites that is >300°C. The highest conductivity value of the composites obtained is 3.06 × 10−2 S cm−1.
Microarchitecture, but Not Bone Mechanical Properties, Is Rescued with Growth Hormone Treatment in a Mouse Model of Growth Hormone Deficiency
Authors: Kristensen Erika , Hallgrímsson Benedikt , Morck Douglas W. , Boyd Steven K.
Published: March 2012

Growth hormone (GH) deficiency is related to an increased fracture risk although it is not clear if this is due to compromised bone quality or a small bone size. We investigated the relationship between bone macrostructure, microarchitecture and mechanical properties in a GH-deficient (GHD) mouse model undergoing GH treatment commencing at an early (prepubertal) or late (postpubertal) time point. Microcomputed tomography images of the femur and L4 vertebra were obtained to quantify macrostructure and vertebral trabecular microarchitecture, and mechanical properties were determined using finite element analyses. In the GHD animals, bone macrostructure was 25 to 43% smaller as compared to the GH-sufficient (GHS) controls (P<0.001). GHD animals had 20% and 19% reductions in bone volume ratio (BV/TV) and trabecular thickness (Tb.Th), respectively. Whole bone mechanical properties of the GHD mice were lower at the femur and vertebra (67% and 45% resp.) than the GHS controls (P<0.001). Both early and late GH treatment partially recovered the bone macrostructure (15 to 32 % smaller than GHS controls) and the whole bone mechanical properties (24 to 43% larger than GHD animals) although there remained a sustained 27–52% net deficit compared to normal mice (P<0.05). Importantly, early treatment with GH led to a recovery of BV/TV and Tb.Th with a concomitant improvement of trabecular mechanical properties. Therefore, the results suggest that GH treatment should start early, and that measurements of microarchitecture should be considered in the management of GHD.
Novel Insights into the Interplay between Apoptosis and Autophagy
Authors: Rikiishi Hidemi
Published: March 2012

For several decades, apoptosis has taken center stage as the principal mechanism of programmed cell death (type I cell death) in mammalian tissues. Autophagic cell death (type II) is characterized by the massive accumulation of autophagic vacuoles in the cytoplasm of cells. The autophagic process is activated as an adaptive response to a variety of extracellular and intracellular stresses, including nutrient deprivation, hormonal or therapeutic treatment, pathogenic infection, aggregated and misfolded proteins, and damaged organelles. Increasing evidence indicates that autophagy is associated with a number of pathological processes, including cancer. The regulation of autophagy in cancer cells is complex since it can enhance cancer cell survival in response to certain stresses, while it can also act to suppress the initiation of cancer growth. This paper focused on recent advances regarding autophagy in cancer and the techniques currently available to manipulate autophagy.
An Unbound Network Coding for Extended IEEE 802.16j Multihop Relay Network
Authors: Sukul Adisak , Chang J. Morris , Bhattarakosol Pattarasinee
Published: March 2012

IEEE 802.16j is an amendment to the IEEE 802.16 broadband wireless access standard to enable the operation of multihop relay stations (RSs). It aims to enhance the coverage, per user throughput of IEEE 802.16e. Comparing with a base station (BS), RS does not need a wireline backhaul and has much lower hardware complexity. Moreover, using RSs can significantly reduce the deployment cost of the system. Unfortunately, there are some tradeoffs in the case of multi-hop RSs. Subscriber stations (SSs), located in a long distance, are suffered from the bottleneck of multi-hop, throughput degradation, and increasing of end-to-end delay. This paper proposes a network coding-based relay scheme for multi-hop relay networks, called NC-BR. It allows RSs to combine two wireless backhaul transmissions into one using the network coding technique. This paper also proposes an improved OFDMA frame structure design for the multi-hop relay network. This technique provides higher utilization for the relay zone by reorganizing the RSs transmission sequence. The analysis and simulation results confirm that the proposed scheme can enhance the throughput gain up to 140% and reduce the end-to-end delay by up to 83%. The simulation results also show that the proposed scheme can reduce the jitter by up to 58%.
Positive Solutions for Neumann Boundary Value Problems of Second‐Order Impulsive Differential Equations in Banach Spaces
Authors: Liu Xiaoya , Li Yongxiang
Published: March 2012

The existence of positive solutions for Neumann boundary value problem of second‐order impulsive differential equations −u″(t) + Mu(t) = f(t, u(t),
t ∈ J, t ≠ tk, , k = 1,2, …, m, u′(0) = u′(1) = θ, in an ordered Banach space E was discussed by employing the fixed point index theory of condensing mapping, where M > 0 is a constant, J = [0,1], f ∈ C(J × K, K), Ik ∈ C(K, K), k = 1,2, …, m, and K is the cone of positive elements in E. Moreover, an application is given to illustrate the main result.
Evaluation on Cartilage Morphology after Intra‐Articular Injection of Titanium Dioxide Nanoparticles in Rats
Authors: Wang Jiangxue , Gao Yu , Hou Ying , Zhao Feng , Pu Fang , Liu Xiaoyu , Wu Zhihong , Fan Yubo
Published: March 2012

Nanoscale wear particles would generate from orthopedic implants with nanoscale surface topography because of residual stress. In this study, the effect of TiO2 nanoparticles on articular cartilage was investigated by intra‐articular injection in rats. Using contrast‐enhanced high‐resolution microcomputed tomography (micro‐CT) technology, the decreased thickness of articular cartilage in distal femur was determined at 1, 7, 14, and 30 days after nanoparticle exposure. A strong linear correlation (r = 0.928, P < 0.0001) was observed with the results obtained by needle probe testing. After exposure to TiO2 nanoparticles, cartilage thickness showed time‐dependent decrease, and cartilage volume was decreased too. Further, the histopathological examination showed the edema chondrocyte and shrinked nucleus in the radial and calcified zone of cartilage. The ultrastructure of articular cartilage implied that the chondrocyte was degenerated, expressing as the condensed chromatin, the dilated endoplasmic reticulum, and the rich mitochondria. Even, the fragments of ruptured endoplasmic reticulum were observed in the cytoplasm of chondrocytes at postexposure day 30. Results indicate that potential damage of articular cartilage was induced by particles existed in knee joint and imply that the biomonitoring should be strengthened in patients with prostheses replacement.
Subretinal Implantation of Electrospun, Short Nanowire, and Smooth Poly(ε-caprolactone) Scaffolds to the Subretinal Space of Porcine Eyes
Authors: Christiansen A. T. , Tao S. L. , Smith M. , Wnek G. E. , Prause J. U. , Young M. J. , Klassen H. , Kaplan H. J. , la Cour M. , Kiilgaard J. F.
Published: March 2012

Biodegradable scaffolds play an important adjunct role in transplantation of retinal progenitor cells (RPCs) to the subretinal space. Poly(ε-Caprolactone) (PCL) scaffolds with different modifications were subretinally implanted in 28 porcine eyes and evaluated by multifocal electroretinography (mfERG) and histology after 6 weeks of observation. PCL Short Nanowire, PCL Electrospun, and PCL Smooth scaffolds were well tolerated in the subretinal space in pigs and caused no inflammation and limited tissue disruption. PCL Short Nanowire had an average rate of preserved overlying outer retina 17% higher than PCL Electrospun and 25% higher than PCL Smooth. Furthermore, PCL Short Nanowire was found to have the most suitable degree of stiffness for surgical delivery to the subretinal space. The membrane-induced photoreceptor damage could be shown on mfERG, but the reductions in P1 amplitude were only significant for the PCL Smooth. We conclude that of the tested scaffolds, PCL Short Nanowire is the best candidate for subretinal implantation.