bluuebunny/crossref_metadata_2025 huggingface dataset:
Conserving energy in real-time storage systems with I/O burstiness
Authors: Manzanares Adam , Ruan Xiaojun , Yin Shu , Qin Xiao , Roth Adam , Najim Mais
Published: March 2010

Energy conservation has become a critical problem for real-time embedded storage systems. Although a variety of approaches for reducing energy consumption have been extensively studied, energy conservation for real-time embedded storage systems is still an open problem. In this article, we propose an energy management strategy, I/O Burstiness for Energy Conservation (IBEC), exploiting the burstiness of real-time embedded storage systems applications. Our approach aims at combining the IBEC energy-management strategy with a Linux-based disk block-scheduling mechanism to conserve the energy of storage systems. Extensive experiments are conducted involving a number of synthetic disk traces as well as real-world data-intensive traces. To evaluate the energy efficiency of IBEC, we compare the performance of IBEC against three existing strategies, namely, PA-EDF, DP-EDF, and EDF. Compared with the alternative strategies, IBEC reduces the power consumption of real-time embedded disks system by up to 60%.
Lock-free synchronization for dynamic embedded real-time systems
Authors: Cho Hyeonjoong , Ravindran Binoy , Jensen E. Douglas
Published: March 2010

We consider lock-free synchronization for dynamic embedded real-time systems that are subject to resource overloads and arbitrary activity arrivals. We model activity arrival behaviors using the unimodal arbitrary arrival model (or UAM). UAM embodies a stronger “adversary” than most traditional arrival models. We derive an upper bound on lock-free retries under the UAM with utility accrual scheduling—the first such result. We establish the tradeoffs between lock-free and lock-based sharing under UAM. These include conditions under which activities' accrued timeliness utility is greater under lock-free than lock-based, and the consequent lower and upper bound on the total accrued utility that is possible with lock-free and lock-based sharing. We confirm our analytical results with a POSIX RTOS implementation.
A cost-effective load-balancing policy for tile-based, massive multi-core packet processors
Authors: Musoll Enric
Published: March 2010

Massive multi-core architectures provide a computation platform with high processing throughput, enabling the efficient processing of workloads with a significant degree of thread-level parallelism found in networking environments.

Communication-centric workloads, like those in LAN and WAN environments, are fundamentally composed of sets of packets, named flows. The packets within a flow usually have dependencies among them, which reduce the amount of parallelism. However, packets of different flows tend to have very few or no dependencies among them, and thus can exploit thread-level parallelism to its fullest extent.

Therefore, in massive tile-based multi-core architectures, it is important that the processing of the packets of a particular flow takes place in a set of cores physically close to each other to minimize the communication latency among those cores. Moreover, it is also desirable to spread out the processing of the different flows across all the cores of the processor in order to minimize the stress on a reduced number of cores, thus minimizing the potential for thermal hotspots and increasing the reliability of the processor. In addition, the burst-like nature of packet-based workloads render most of the cores idle most of the time, enabling large power savings by power gating these idle cores.

This work presents a high-level study of the performance, power, and thermal behavior of tile-based architectures with a large number of cores executing flow-based packet workloads, and proposes a load-balancing policy of assigning packets to cores that minimizes the communication latency while featuring a hotspot-free thermal profile.
Hierarchical agent monitoring design approach towards self-aware parallel systems-on-chip
Authors: Guang Liang , Nigussie Ethiopia , Rantala Pekka , Isoaho Jouni , Tenhunen Hannu
Published: March 2010

Hierarchical agent framework is proposed to construct a monitoring layer towards self-aware parallel systems-on-chip (SoCs). With monitoring services as a new design dimension, systems are capable of observing and reconfiguring themselves dynamically at all levels of granularity, based on application requirements and platform conditions. Agents with hierarchical priorities work adaptively and cooperatively to maintain and improve system performance in the presence of variations and faults. Function partitioning of agents and hierarchical monitoring operations on parallel SoCs are analyzed. Applying the design approach on the Network-on-Chip (NoC) platform demonstrates the design process and benefits using the novel approach.
Reliability through redundant parallelism for micro-satellite computing
Authors: McLoughlin Ian Vince , Bretschneider Timo Rolf
Published: March 2010

Spacecraft typically employ rare and expensive radiation-tolerant, radiation-hardened, or at least military qualified parts for computational and other mission critical subsystems. Reasons include reliability in the harsh environment of space, and systems compatibility or heritage with previous missions. The overriding reliability concern leads most satellite computing systems to be rather conservative in design, avoiding novel or commercial-off-the-shelf components. This article describes an alternative approach: an FPGA-arbitrated parallel architecture that allows unqualified commercial devices to be incorporated into a computational device with aggregate reliability figures similar to those of traditional space-qualified alternatives. Apart from the obvious cost benefits in moving to commercial-off-the-shelf devices, these are attractive in situations where lower power consumption and/or higher processing performance are required. The latter argument is particularly of major importance at a time when the gap between required and available processing capability in satellites is widening. An analysis compares the proposed architecture to typical alternatives, maintaining risk of failure to within required levels, and discusses key applications for the parallel architecture.
Online memory compression for embedded systems
Authors: Yang Lei , Dick Robert P. , Lekatsas Haris , Chakradhar Srimat
Published: March 2010

Memory is a scarce resource during embedded system design. Increasing memory often increases packaging costs, cooling costs, size, and power consumption. This article presents CRAMES, a novel and efficient software-based RAM compression technique for embedded systems. The goal of CRAMES is to dramatically increase effective memory capacity without hardware or application design changes, while maintaining high performance and low energy consumption. To achieve this goal, CRAMES takes advantage of an operating system's virtual memory infrastructure by storing swapped-out pages in compressed format. It dynamically adjusts the size of the compressed RAM area, protecting applications capable of running without it from performance or energy consumption penalties. In addition to compressing working data sets, CRAMES also enables efficient in-RAM filesystem compression, thereby further increasing RAM capacity.

CRAMES was implemented as a loadable module for the Linux kernel and evaluated on a battery-powered embedded system. Experimental results indicate that CRAMES is capable of doubling the amount of RAM available to applications running on the original system hardware. Execution time and energy consumption for a broad range of examples are rarely affected. When physical RAM is reduced to 62.5% of its original quantity, CRAMES enables the target embedded system to support the same applications with reasonable performance and energy consumption penalties (on average 9.5% and 10.5%), while without CRAMES those applications either may not execute or suffer from extreme performance degradation or instability. In addition to presenting a novel framework for dynamic data memory compression and in-RAM filesystem compression in embedded systems, this work identifies the software-based compression algorithms that are most appropriate for use in low-power embedded systems.
MobileAccessibility
Authors: Jayant Chandrika
Published: March 2010

There is a significant need for access to low-cost assistive mobile services through standard devices. Many special purpose devices that provide services are specialized for few functions, are usually not networked, and are expensive and difficult to sustain. Mobile devices and their sensors, along with audio or tactile output, show immense promise for improved daily accessibility to the world for blind people on the go. Particularly, the camera has the potential to expand environmental knowledge using context and computer vision. This research will investigate general camera interaction techniques, mobile device and camera accessibility for blind users, and computer vision techniques for recognition given mobile phone limitations. These studies along with formative studies and focus groups with users will inform the design, implementation, and evaluation of future lab and field studies for semi-autonomous focalization with the camera for blind users.
An online multimedia language assistant for people with aphasia and other language barriers
Authors: Ma Xiaojuan
Published: March 2010

Individuals with aphasia, a language disorder, are seldom able to utilize the Internet as a source of information, because their disability makes many written words incomprehensible. A similar situation exists for individuals who read and speak a second language but do not possess a vocabulary as extensive as in their native language. Pictures have been demonstrated to help in both cases. However, few existing paper or electronic picture dictionaries provide efficient, scalable, and adaptable support for looking up unknown terms encountered when browsing the web. For my thesis research, I am designing and developing an Online Multimedia Language Assistant, which allows a reader to click on an unknown word and receive interpretations of the word in as many as five different multimedia representations. The system provides a popup dictionary, images, animations and audio, where applicable. It is also adaptable (by user) and adaptive (system).
Dissertation corner
Authors: Goldstein Moshe
Published: March 2010

A key factor in the properties of biological molecules is their structure. This research has focused on the problem of
protein structure prediction
due to the critical role of peptides and proteins in the normal biological functionality of cells and organisms. At sufficiently low temperatures, though not always, the structure of the minimal free energy corresponds to the global minimum of its force field (FF) -- its Potential Energy Surface (PES), which is a function expressing the potential energy interactions inside the molecule. The problem of predicting the
native
(or
folded
) structure of a polypeptide given its sequence or some unfolded structure
is
the problem of finding that global minimum. This problem is computationally hard because we know that a polypeptide's PES has an estimated number of minima, exponential on its sequence length.
Volunteer computing
Authors: Anderson David P.
Published: March 2010

Computers continue to get faster exponentially, but the computational demands of science are growing even faster. Extreme requirements arise in at least three areas.
Clouds at the crossroads
Authors: Vigfusson Ymir , Chockler Gregory
Published: March 2010

Despite its promise, most cloud computing innovations have been almost exclusively driven by a few industry leaders, such as Google, Amazon, Yahoo!, Microsoft, and IBM. The involvement of a wider research community, both in academia and industrial labs, has so far been patchy without a clear agenda. In our opinion, the limited participation stems from the prevalent view that clouds are mostly an engineering and business-oriented phenomenon based on stitching together existing technologies and tools.
Scientific workflows and clouds
Authors: Juve Gideon , Deelman Ewa
Published: March 2010

In recent years, empirical science has been evolving from physical experimentation to computation-based research. In astronomy, researchers seldom spend time at a telescope, but instead access the large number of image databases that are created and curated by the community [42]. In bioinformatics, data repositories hosted by entities such as the National Institutes of Health [29] provide the data gathered by Genome-Wide Association Studies and enable researchers to link particular genotypes to a variety of diseases.
The Analysis of Multiple Genome Comparisons in GenusEscherichiaand Its Application to the Discovery of Uncharacterised Metabolic Genes in UropathogenicEscherichia coliCFT073
Authors: Bryant William A. , Krabben Preben , Baganz Frank , Zhou Yuhong , Ward John M.
Published: March 2010

A survey of a complete gene synteny comparison has been carried out between twenty fully sequenced strains from the genusEscherichiawith the aim of finding yet uncharacterised genes implicated in the metabolism of uropathogenic strains ofE. coli(UPEC). Several sets of adjacent colinear genes have been identified which are present in all four UPEC included in this study (CFT073, F11, UTI89, and 536), annotated with putative metabolic functions, but are not found in any other strains considered. An operon closely homologous to that encoding the L-sorbose degradation pathway inKlebsiella pneumoniaehas been identified inE. coliCFT073; this operon is present in all of the UPEC considered, but only in 7 of the other 16 strains. The operon's function has been confirmed by cloning the genes intoE. coliDH5αand testing for growth on L-sorbose. The functional genomic approach combining in silico and in vitro work presented here can be used as a basis for the discovery of other uncharacterised genes contributing to bacterial survival in specific environments.
Severe Hyperkalemia and Bilateral Adrenal Metastasis
Authors: Nagler Michael , Müller Beat , Briner Verena , Winterhalder Ralph
Published: March 2010

Adrenal metastases are a common finding in metastatic lung and breast cancer. Often there are no clinical symptoms suggesting them. In this paper, we present a case of a 66-year-old man with metastatic lung cancer suffering from severe hyperkaliemia due to hypoaldosteronism as a result of bilateral adrenal metastasis.
Use of a Distal Radius Endoprosthesis Following Resection of a Bone Tumour: A Case Report
Authors: Gokaraju Kishan , Sri-Ram Kesavan , Donaldson James , Parratt Michael T. R. , Blunn Gordon W. , Cannon Steve R. , Briggs Timothy W. R.
Published: March 2010

Limited literature is available on the reconstruction of the distal radius using prosthetic replacement following resection of a bone tumour. We present the first reported case, in the English literature, of the use of an entirely metal endoprosthesis for the reconstruction of the distal radius. This case involves a 66-year-old male who was treated for giant cell tumour of the distal radius with surgical excision of the lesion and replacement of the defect using a predominantly titanium endoprosthesis. He was followed-up for 56 months following surgery and had a good functional outcome with no associated pain or complications. We propose that the use of a primarily titanium endoprosthesis for the reconstruction of a bone defect of the distal radius is a suitable alternative, providing good function of the forearm with satisfactory range of movement at the wrist and adequate pain relief.
Xenon Anesthesia Improves Respiratory Gas Exchanges in Morbidly Obese Patients
Authors: Abramo Antonio , Di Salvo Claudio , Foltran Francesca , Forfori Francesco , Anselmino Marco , Giunta Francesco
Published: March 2010

Background. Xenon-in-oxygen is a high density gas mixture and may improve PaO2/FiO2 ratio in morbidly obese patients uniforming distribution of ventilation during anesthesia.Methods. We compared xenon versus sevoflurane anesthesia in twenty adult morbidly obese patients (BMI>35) candidate for roux-en-Y laparoscopic gastric bypass and assessed PaO2/FiO2 ratio at baseline, at 15 min from induction of anaesthesia and every 60 min during surgery. Differences in intraoperative and postoperative data including heart rate, systolic and diastolic pressure, oxygen saturation, plateau pressure, eyes opening and extubation time, Aldrete score on arrival to the PACU were compared by the Mann-Whitney test and were considered as secondary aims. Moreover the occurrence of side effects and postoperative analgesic demand were assessed.Results. In xenon group PaO2-FiO2 ratio was significantly higher after 60 min and 120 min from induction of anesthesia; heart rate and overall remifentanil consumption were lower; the eyes opening time and the extubation time were shorter; morphine consumption at 72 hours was lower; postoperative nausea was more common.Conclusions. Xenon anesthesia improved PaO2/FiO2 ratio and maintained its distinctive rapid recovery times and cardiovascular stability. A reduction of opioid consumption during and after surgery and an increased incidence of PONV were also observed in xenon group.
Variations in the Presentation of Aphasia in Patients with Closed Head Injuries
Authors: Kavanagh Dara Oliver , Lynam Conor , Düerk Thorsten , Casey Mary , Eustace Paul W.
Published: March 2010

Impairments of speech and language are important consequences of head injury as they compromise interaction between the patient and others. A large spectrum of communication deficits can occur. There are few reports in the literature of aphasia following closed head injury despite the common presentation of closed head injury. Herein we report two cases of closed head injuries with differing forms of aphasia. We discuss their management and rehabilitation and present a detailed literature review on the topic. In a busy acute surgical unit one can dismiss aphasia following head injury as behaviour related to intoxication. Early recognition with prolonged and intensive speech and language rehabilitation therapy yields a favourable outcome as highlighted in our experience. These may serve as a reference for clinicians faced with this unusual outcome.
Clinical Presentation and Conservative Management of Tympanic Membrane Perforation during Intrapartum Valsalva Maneuver
Authors: Baum Jonathan D. , Rattigan Meghan I. , Sills Eric Scott , Walsh Anthony P. H.
Published: March 2010

Background.Tympanic membrane perforation may occur when ear pressures are excessive, including valsalva maneuver associated with active labor and vaginal delivery. A pressure differential across the eardrum of about 5 psi can cause rupture; the increased intraabdominal pressure spikes repeatedly manifested by “pushing” during second-stage labor easily approach (and may exceed) this level.Material and Method.We describe a healthy 21-year old nulliparous patient admitted in active labor at 39-weeks' gestational age.Results.Blood appeared asymptomatically in the left ear canal at delivery during active, closed-glottis pushing. Otoscopic examination confirmed perforation of the left tympanic membrane. Complete resolution of the eardrum rupture was noted at postpartum check-up six weeks later.Conclusion.While the precise incidence of intrapartum tympanic membrane rupture is not known, it may be unrecognized without gross blood in the ear canal or subjective hearing loss following delivery. Only one prior published report on tympanic membrane perforation during delivery currently appears in the medical literature; this is the first English language description of the event. Since a vigorous and repetitive valsalva effort is common in normal vaginal delivery, clinicians should be aware of the potential for otic complications associated with the increased intraabdominal pressure characteristic of this technique.
Green′s Function and Convergence of Fourier Series for Elliptic Differential Operators with Potential from Kato Space
Authors: Serov Valery
Published: March 2010

We consider the Friedrichs self‐adjoint extension for a differential
operator A of the form A = A0 + q(x)·, which is defined on a bounded
domain Ω ⊂ ℝn, n ≥ 1 (for n = 1 we assume that Ω = (a, b) is a finite
interval). Here A0 = A0(x, D) is a formally self‐adjoint and a uniformly elliptic differential operator of order 2m with bounded smooth
coefficients and a potential q(x) is a real‐valued integrable function
satisfying the generalized Kato condition. Under these assumptions
for the coefficients of A and for positive λ large enough we obtain the
existence of Green′s function for the operator A + λI and its estimates
up to the boundary of Ω. These estimates allow us to prove the absolute and uniform convergence up to the boundary of Ω of Fourier
series in eigenfunctions of this operator. In particular, these results
can be applied for the basis of the Fourier method which is usually
used in practice for solving some equations of mathematical physics.
Navigating Cultural Worlds and Negotiating Identities: A Conceptual Model
Authors: Mistry Jayanthi , Wu Jean
Published: March 2010

For children from culturally and linguistically diverse backgrounds the ability to maintain flexible identities and integrate multiple facets of self is a crucial developmental task. We present a conceptual model for the development of expertise in navigating across cultures, delineating how community characteristics interact with family and individual practices to create the conditions under which children develop expertise in navigating multiple cultural worlds and identities. Core constructs and propositions about the nature of relations are derived from a multidisciplinary review of extant scholarship. To illustrate an application of the model, we compare two waves of immigration to the US from the Indian subcontinent and derive potential hypotheses about how differences in immigration history and circumstances of settlement in the host country are associated with the processes of negotiating identities.
Early Expression of the Androgen Receptor in the Sertoli Cells of a Marsupial Coincides with Downregulation of Anti-Müllerian Hormone at the Time of Urogenital Virilization
Authors: Racine C. , Pask A.J. , Wijayanti G.E. , di Clemente N. , Picard J.-Y. , Shaw G. , Renfree M.B. , Josso N.
Published: March 2010

Anti-Müllerian hormone (AMH), responsible for the regression of Müllerian ducts, is strongly expressed by eutherian fetal and postnatal Sertoli cells. Both AMH and testosterone levels are high during the period of fetal reproductive tract virilization which occurs largely in utero in eutherian mammals. Taking advantage of the fact that differentiation of the urogenital tract occurs after birth in marsupials, we studied the ontogeny and regulation of AMH in the tammar wallaby testis and related it to the expression of the androgen receptor in Sertoli cells. Testicular AMH expression was high between days 10–30 post partum, then fell to basal levels by day 60 and remained low until day 90, the oldest age examined. AMH expression was repressed by treatment of male pouch young with the potent androgen androstanediol. Thus, in the tammar, AMH expression decreases in response to androgen at the time of initial urogenital masculinization, in contrast to the situation in humans in which AMH is repressed by testosterone only at the time of puberty. The difference might be explained by the timing of androgen receptor expression which appears in tammar Sertoli cells at around day 40 of pouch life but only at a later developmental stage in eutherians.
Gender Difference in the Prediction of Weight Loss by Leptin among Overweight Adults
Authors: Ramel Alfons , Arnarson Atli , Parra Dolores , Kiely Mairead , Bandarra Narcisa M. , Martínez J. Alfredo , Thorsdottir Inga
Published: March 2010

Background/Aim: Leptin plays an important role in energy metabolism. The primary objective of the study was to investigate whether baseline leptin levels predict weight loss during a dietary intervention in overweight and obese individuals. Methods: A total of 324 individuals (138 men and 186 women, aged 20–40 years, BMI 27.5–32.5) were recruited in Iceland, Ireland and Spain. The intervention lasted for 8 consecutive weeks, and subjects were instructed to follow a diet, energy restricted by 30%. Anthropometric variables were assessed before and after the intervention. Leptin concentration was measured at baseline and corrected for fat mass. Linear models were used to find out which variables predicted weight loss. Results: At end point, significant weight loss was observed (5.16 ± 3.06 kg, p < 0.001). High baseline leptin concentrations were a significant negative predictor of weight loss in men (p = 0.028), with a predicted difference of 1.8 kg between the lowest and highest leptin quartile. Conclusion: Our study underlines the importance of leptin in energy metabolism. Plasma leptin concentrations at baseline are a predictor of weight loss in overweight men after an 8-week dietary intervention. The same effect was not observed in overweight women, which suggests that the role of leptin in the regulation of weight is gender specific.
Non-Coding RNAs in Mammalian Sexual Development
Authors: McFarlane L. , Wilhelm D.
Published: March 2010

The present decade is witnessing a paradigm shift in our understanding of gene regulation. RNA, once relegated to an intermediary between DNA and protein, has emerged as a key contributor in the coordination of complex developmental pathways. For sexually reproducing organisms, propagation of the species is accomplished via an elaborate sexual phenotype. In mammals this consists of a highly complex cell lineage that has the capacity for intricate self-differentiation whilst maintaining the potential to generate all cell types upon fertilization. In addition, mammals possess a diverse range of somatic reproductive tissues and organs that often undergo dynamic morphological changes in response to a variety of external and internal cues. Although the protein component required to mediate these processes continues to be vigorously investigated, it is becoming increasingly apparent that an understanding of the non-coding RNA (ncRNA) component is required to develop a comprehensive picture of mammalian sexual development.
High-Sensitivity Troponin T Concentrations in Acute Chest Pain Patients Evaluated With Cardiac Computed Tomography
Authors: Januzzi James L. , Bamberg Fabian , Lee Hang , Truong Quynh A. , Nichols John H. , Karakas Mahir , Mohammed Asim A. , Schlett Christopher L. , Nagurney John T. , Hoffmann Udo , Koenig Wolfgang
Published: March 2010

Background—

For evaluation of patients with chest pain and suspected acute coronary syndrome (ACS), consensus guidelines recommend use of a cardiac troponin cut point that corresponds to the 99th percentile of a healthy population. Most conventional troponin methods lack sufficient precision at this low level.

Methods and Results—

In a cross-sectional study, 377 patients (mean age 53.7 years, 64.2% male) with chest pain and low to intermediate likelihood for ACS were enrolled in the emergency department. Blood was tested with a precommercial high-sensitivity troponin T assay (hsTnT) and compared with a conventional cardiac troponin T method. Patients underwent a 64-slice coronary computed tomography coronary angiogram at the time of phlebotomy, on average 4 hours from initial presentation. Among patients with acute chest pain, 37 (9.8%) had an ACS. Using the 99th percentile cut point for a healthy population (13 pg/mL), hsTnT had 62% sensitivity, 89% specificity, 38% positive predictive value, and 96% negative predictive value for ACS. Compared with the cardiac troponin T method, hsTnT detected 27% more ACS cases (
P
=.001), and an hsTnT above the 99th percentile strongly predicted ACS (odds ratio 9.0, 95% confidence interval 3.9 to 20.9,
P
<0.001). Independent of ACS diagnosis, computed tomography angiography demonstrated that concentrations of hsTnT were determined by numerous factors, including the presence and severity of coronary artery disease, left ventricular mass, left ventricular ejection fraction, and regional left ventricular dysfunction.

Conclusions—

Among low- to intermediate-risk patients with chest pain, hsTnT provides good sensitivity and specificity for ACS. Elevation of hsTnT identifies patients with myocardial injury and significant structural heart disease, irrespective of the diagnosis of ACS.
Cyclooxygenase 1–Derived Prostaglandin E
2
and EP1 Receptors Are Required for the Cerebrovascular Dysfunction Induced by Angiotensin II
Authors: Capone Carmen , Faraco Giuseppe , Anrather Josef , Zhou Ping , Iadecola Costantino
Published: March 2010

Prostaglandin E
2
(PGE
2
) EP1 receptors (EP1Rs) may contribute to hypertension and related end-organ damage. Because of the key role of angiotensin II (Ang II) in hypertension, we investigated the role of EP1R in the cerebrovascular alterations induced by Ang II. Mice were equipped with a cranial window, and cerebral blood flow was monitored by laser-Doppler flowmetry. The attenuation in cerebral blood flow responses to whisker stimulation (−46±4%) and the endothelium-dependent vasodilator acetylcholine (−40±4%) induced by acute administration of Ang II (250 ng/kg per minute; IV for 30 to 40 minutes) were not observed after cyclooxygenase 1 or EP1R inhibition or in cyclooxygenase 1 or EP1-null mice. In contrast, cyclooxygenase 2 inhibition or genetic inactivation did not prevent the attenuation. Ang II–induced oxidative stress was not observed after cyclooxygenase 1 or EP1R inhibition or in EP1R-null mice. Prostaglandin E
2
reinstated the Ang II–induced cerebrovascular dysfunction and oxidative stress after cyclooxygenase 1 inhibition. Brain prostaglandin E
2
levels were not increased by Ang II but were attenuated by cyclooxygenase 1 and not cyclooxygenase 2 inhibition. The cerebrovascular dysfunction induced by 14-day administration of “slow-pressor” doses of Ang II (600 ng/kg per minute) was attenuated by neocortical application of SC51089. Cyclooxygenase 1 immunoreactivity was observed in microglia and EP1R in endothelial cells. We conclude that the cerebrovascular dysfunction induced by Ang II requires activation of EP1R by constitutive production of prostaglandin E
2
derived from cyclooxygenase 1. The findings provide the first evidence that EP1Rs are involved in the deleterious cerebrovascular effects of Ang II and suggest new therapeutic approaches to counteract them.
Endothelial Nitric Oxide Synthase–Independent Protective Action of Statin Against Angiotensin II–Induced Atrial Remodeling via Reduced Oxidant Injury
Authors: Yagi Shusuke , Akaike Masashi , Aihara Ken-ichi , Ishikawa Kazue , Iwase Takashi , Ikeda Yasumasa , Soeki Takeshi , Yoshida Sumiko , Sumitomo-Ueda Yuka , Matsumoto Toshio , Sata Masataka
Published: March 2010

Activation of the renin-angiotensin system exacerbates atrial remodeling, leading to atrial fibrillation and thrombosis, especially in a condition with decreased NO bioavailability. Recently, it has been reported that statins reduce the incidence of atrial fibrillation through attenuation of atrial remodeling; however, the mechanisms have not been completely elucidated. Therefore, we aimed to clarify the beneficial effect of statin on atrial remodeling in condition with reduced NO bioavailability. Endothelial NO synthase
−/−
mice were sham operated or infused with angiotensin II (Ang II) via an osmotic minipump for 2 weeks, and Ang II–infused mice were divided into 3 treatment groups: pitavastatin, Tempol (a free radical scavenger), or vehicle. Echocardiography and electrocardiography showed that Ang II infusion caused left atrial enlargement and a high incidence of atrial fibrillation, whereas pitavastatin and Tempol prevented these abnormalities. In histological analysis, Ang II–induced atrial interstitial fibrosis, perivascular fibrosis, and cardiomyocyte hypertrophy were all attenuated by pitavastatin and Tempol. Immunohistochemical staining showed that Ang II downregulated thrombomodulin and tissue factor pathway inhibitor and upregulated tissue factor and plasminogen activator inhibitor 1 in the left atrium and that pitavastatin and Tempol corrected the thrombogenic condition. Moreover, pitavastatin and Tempol reduced Ang II–induced atrial superoxide production and atrial transforming growth factor-β1 expression and Smad 2/3 phosphorylation. Atrial rac1-GTPase activity, known to activate NADPH oxidase, was attenuated by pitavastatin but not by Tempol. In conclusion, pitavastatin exerts endothelial NO synthase–independent protective actions against Ang II–induced atrial remodeling and atrial fibrillation with enhanced thrombogenicity through suppression of oxidant injury.
Behavioral Neurocardiac Training in Hypertension
Authors: Nolan Robert P. , Floras John S. , Harvey Paula J. , Kamath Markad V. , Picton Peter E. , Chessex Caroline , Hiscock Natalie , Powell Jonathan , Catt Michael , Hendrickx Hilde , Talbot Duncan , Chen Maggie H.
Published: March 2010

It is not established whether behavioral interventions add benefit to pharmacological therapy for hypertension. We hypothesized that behavioral neurocardiac training (BNT) with heart rate variability biofeedback would reduce blood pressure further by modifying vagal heart rate modulation during reactivity and recovery from standardized cognitive tasks (“mental stress”). This randomized, controlled trial enrolled 65 patients with uncomplicated hypertension to BNT or active control (autogenic relaxation), with six 1-hour sessions over 2 months with home practice. Outcomes were analyzed with linear mixed models that adjusted for antihypertensive drugs. BNT reduced daytime and 24-hour systolic blood pressures (−2.4±0.9 mm Hg,
P
=0.009, and −2.1±0.9 mm Hg,
P
=0.03, respectively) and pulse pressures (−1.7±0.6 mm Hg,
P
=0.004, and −1.4±0.6 mm Hg,
P
=0.02, respectively). No effect was observed for controls (
P
>0.10 for all indices). BNT also increased RR-high-frequency power (0.15 to 0.40 Hz;
P
=0.01) and RR interval (
P
<0.001) during cognitive tasks. Among controls, high-frequency power was unchanged (
P
=0.29), and RR interval decreased (
P
=0.03). Neither intervention altered spontaneous baroreflex sensitivity (
P
>0.10). In contrast to relaxation therapy, BNT with heart rate variability biofeedback modestly lowers ambulatory blood pressure during wakefulness, and it augments tonic vagal heart rate modulation. It is unknown whether efficacy of this treatment can be improved with biofeedback of baroreflex gain. BNT, alone or as an adjunct to drug therapy, may represent a promising new intervention for hypertension.
Greater Cardiovascular Responses to Laboratory Mental Stress Are Associated With Poor Subsequent Cardiovascular Risk Status
Authors: Chida Yoichi , Steptoe Andrew
Published: March 2010

An increasing number of studies has tested whether greater cardiovascular responses to acute mental stress predict future cardiovascular disease, but results have been variable. This review aimed quantitatively to evaluate the association between cardiovascular responses to laboratory mental stress and subsequent cardiovascular risk status in prospective cohort studies. We searched general bibliographic databases, PsycINFO, Web of Science, and PubMed, up to December 2009. Two reviewers independently extracted data on study characteristics, quality, and estimates of associations. There were 169 associations (36 articles) of stress reactivity and 30 associations (5 articles) of poststress recovery in relation to future cardiovascular risk status, including elevated blood pressure, hypertension, left ventricular mass, subclinical atherosclerosis, and clinical cardiac events. The overall meta-analyses showed that greater reactivity to and poor recovery from stress were associated longitudinally with poor cardiovascular status (
r
=0.091 [95% CI: 0.050 to 0.132],
P
<0.001, and
r
=0.096 [95% CI: 0.058 to 0.134],
P
<0.001, respectively). These findings were supported by more conservative analyses of aggregate effects and by subgroup analyses of the methodologically strong associations. Notably, incident hypertension and increased carotid intima-media thickness were more consistently predicted by greater stress reactivity and poor stress recovery, respectively, whereas both factors were associated with higher future systolic and diastolic blood pressures. In conclusion, the current meta-analysis suggests that greater responsivity to acute mental stress has an adverse effect on future cardiovascular risk status, supporting the use of methods of managing stress responsivity in the prevention and treatment of cardiovascular disease.
Tonic Chemoreflex Activation Contributes to Increased Sympathetic Nerve Activity in Heart Failure–Related Anemia
Authors: Franchitto Nicolas , Despas Fabien , Labrunée Marc , Roncalli Jérome , Boveda Serge , Galinier Michel , Senard Jean-Michel , Pathak Atul
Published: March 2010

Sympathetic activation contributes to both the initiation and progression of heart failure. The role of anemia in determining sympathetic overactivity in chronic heart failure (CHF) patients is unknown. We tested the hypothesis that, in CHF patients, anemia could lead to increased sympathetic activity through tonic activation of excitatory chemoreceptor afferents. We conducted a double-blind, randomized, vehicle-controlled study to examine the effect of chemoreflex deactivation on muscle sympathetic nerve activity in CHF patients with and without anemia. We compared the effect of breathing 100% oxygen for 15 minutes in 18 stable CHF patients with anemia and 18 control CHF patients matched for age, sex, blood pressure, and body mass index. Baseline muscle sympathetic nerve activity was significantly elevated in CHF patients with anemia compared with patients with CHF alone (56.0±3.2 versus 45.5±3.1 bursts per minute;
P
<0.0237). Administration of 100% oxygen led to a significant decrease in muscle sympathetic nerve activity in CHF patients with anemia (from 56.0±3.4 to 50.9±3.2 bursts per minute;
P
<0.0019). In contrast, neither room air nor 100% oxygen changed muscle sympathetic nerve activity or hemodynamics in patients with CHF alone. We report for the first time direct evidence of increased sympathetic nerve traffic in patients with CHF-related anemia. Sympathetic hyperactivity in patients with CHF and anemia is partially chemoreflex mediated and could explain how anemia contributes to the progression of CHF and increases morbidity and mortality in these patients.
Sex Differences in Protection Against Angiotensin II–Induced Endothelial Dysfunction by Manganese Superoxide Dismutase in the Cerebral Circulation
Authors: Chrissobolis Sophocles , Faraci Frank M.
Published: March 2010

Angiotensin II (Ang II) produces oxidative stress and endothelial dysfunction in blood vessels. The vasculature from females may be protected against deleterious effects of Ang II. We tested the hypothesis that manganese superoxide dismutase (MnSOD) protects against Ang II–induced endothelial dysfunction. Experiments were performed in C57Bl/6, wild-type (MnSOD
+/+
), and MnSOD-deficient (MnSOD
+/−
) mice treated systemically with vehicle or Ang II. Basilar arteries were isolated from mice treated for 1 week with a nonpressor dose of Ang II (0.28 mg/kg per day). Ang II treatment produced superoxide-mediated impairment of responses to the endothelium-dependent vasodilator acetylcholine (
P
<0.05). In male but not female MnSOD
+/+
mice, Ang II modestly inhibited responses to acetylcholine (
P
<0.05). In contrast, Ang II selectively impaired these responses by up to 70% in male MnSOD
+/−
mice (
P
<0.05), and this effect was reversed by Tempol (
P
<0.05). Ang II had no effect on acetylcholine responses in MnSOD
+/−
female mice. Vascular superoxide levels after treatment with an inhibitor of CuZn and extracellular superoxide dismutase were higher in Ang II–treated versus vehicle-treated MnSOD
+/−
mice. Thus, a nonpressor dose of Ang II produces endothelial dysfunction in male mice only, suggesting that the female vasculature is protected from Ang II. In male but not female mice, MnSOD deficiency enhanced endothelial dysfunction, suggesting that MnSOD normally protects the vasculature during disease states in which Ang II contributes to vascular dysfunction.
Erythropoietin Increases Expression and Function of Vascular Copper- and Zinc-Containing Superoxide Dismutase
Authors: d'Uscio Livius V. , Smith Leslie A. , Katusic Zvonimir S.
Published: March 2010

Previous studies have shown that treatment with erythropoietin (EPO) exerts vascular protective effects. The exact mechanisms responsible for these effects are not completely understood. In the present study, we hypothesized that EPO stimulates expression and activity of copper- and zinc-containing superoxide dismutase (SOD1), thus protecting vascular tissue from oxidative stress induced by excessive concentrations of superoxide anions. EPO treatment of wild-type mice for 2 weeks (1000 U/kg, SC, biweekly) significantly increased aortic expression of SOD1. This effect resulted in a significant reduction of superoxide anion concentrations in aorta of treated mice. The ability of EPO to reduce vascular production of superoxide anions was abolished in SOD1-deficient mice. In a mouse model of wire-induced injury of the common carotid artery, treatment of wild-type mice with EPO prevented pathological remodeling, whereas the vascular effect of EPO was absent in SOD1-deficient mice. Our findings demonstrate that treatment with EPO increases vascular expression of SOD1. This effect appears to be an important molecular mechanism underlying vascular protection by EPO.
Multicultural Experience, Idea Receptiveness, and Creativity
Authors: Leung Angela Ka-yee , Chiu Chi-yue
Published: March 2010

Inspired by recent advances in creative cognition research, the authors examined in the current research some creative benefits of multicultural experiences. Study 1 showed that European American undergraduates had better creative performance immediately after being exposed to American and Chinese cultures or to a hybrid culture formed by fusing American and Chinese cultures; this effect was also observed 5 to 7 days after the initial exposure. Studies 2 and 3 showed that exposure to multicultural experiences is positively related to the likelihood of engaging in some creativity-supporting processes—generation of unconventional ideas (Study 2) and receptiveness to ideas originated from foreign cultures (Study 3). Finally, in Studies 4 and 5, the authors found that need for cognitive closure (or the need for firm answers) and existential terror significantly attenuated the positive link between multicultural experiences and receptiveness to ideas originated from foreign cultures. The authors discussed these findings’ implications on multicultural learning and creativity.
The Logic of Deliberate Structural Inertia
Authors: Schwarz Gavin M.
Published: March 2010

This article responds to criticism that structural inertia theory neglects the internal influences on organizational adaptation. It develops a model exploring the logic of key decision makers in purposely endorsing structural inertia during organizational change. This response is labeled deliberate inertia, which is part of a typology delineating structural inertia. The model depicts a type of deductive reasoning showing the way that the structural status quo is intentionally selected when undertaking change for reasons outside population ecology. In asserting that structural inertia theory generally overlooks stability that stems from subjective sense making, the model indicates how decision makers delineate a belief in inertia (Layer 1 of the model), and then defend (Layer 2) and legitimize (Layer 3) this choice. This endorsement is deliberate and underscores the influence of decision makers in adopting inertia. Consequently, the model highlights why structural inertia is chosen regardless of pressures for and expectations of more fundamental structural change. The article discusses the implications of how this choice affects eventual structural change.
Time perspective and identity formation: Short-term longitudinal dynamics in college students
Authors: Luyckx Koen , Lens Willy , Smits Ilse , Goossens Luc
Published: March 2010

Planning for the future and developing a personalized identity are conceived of as important developmental tasks that adolescents and emerging adults are confronted with on the pathway to adulthood. The present study set out to examine whether both tasks develop in tandem by using a short-term longitudinal dataset consisting of 371 college students assessed at two time-points, four months apart. Identity formation was assessed using identity commitment and three identity processing styles; time perspective was assessed using the present-hedonistic, present-fatalistic, and future-oriented perspectives. Using cross-lagged structural equation modeling, three competing models were tested: a time perspective main-effects model; an identity main-effects model; and a reciprocal model. In accordance with expectations, evidence was found for the reciprocal model with identity formation and time perspective mutually reinforcing one another across time. Implications and suggestions for future research are discussed.
Schizophrenia genes, epigenetics and psychoneuroimmunology therapeutics: all make sense now?
Authors: Müller Norbert , Dursun Serdar M
Published: March 2010

Genetics, epigenetics, infection as an environmental factor, functional findings for the immune system, and a therapeutic approach with anti-inflammatory therapy provide evidence for a pivotal role of the immune system in schizophrenia. This field, therefore, should focus more on further schizophrenia research.
Physico-mechanical Effects of Surface-modified Sorgum Stalk Powder on Reinforced Rubber
Authors: Yakubu M.K. , Gumel M.S. , Umar A. , Metelerkamp R.
Published: March 2010

Stalk of sorghum was crushed into fine particle size and given three surface treatments: with groundnut oil, alkali, and 3-chloro-2-hydroxyl propyl trimethylammonium chloride. It was presumed that the oil treatment will preclude any negative surface potential that cellulose is known to acquire in aqueous environment. The alkali treatment was to remove the natural surface admixtures but to preserve the negative surface potential, and the tertiary ammonium salt was to confer positive potential to it. The four samples including the untreated fiber were used to produce fiber-reinforced natural rubber composite at varying filler loadings. The pycnometric specific density measurement indicated the following decreasing trend: cationized filler, untreated, causticized, and finally the oil treated. In each case, the density increased with filler volume. The tensile strength of the composites also varied such that both the cationized and alkali-treated fillers recorded higher values than the untreated filler, the oil-treated filler was the least. However, the oil-treated filler did best with the elongation at break for filler loading higher than 40 phr; for loadings lower than 40 phr, the alkali-treated filler did better. The cationized filler recorded low values but was better than the untreated filler. The impact tests demonstrated critical loading effect for all the different samples; the trend showed increase from 10 to 40 phr and then declined, the untreated and the oil-treated did better than the causticized and cationized which recorded the least value. The hardness index did not show much difference between the untreated, causticized, and cationized fillers both of which did better than the oil treated. This work has shown some general improvements arising from cationization of cellulosic filler as reinforcing material for natural rubber.