bluuebunny/crossref_metadata_2025 huggingface dataset:
Altered muscle activation following hamstring injuries
Authors: Sole Gisela , Milosavljevic Stephan , Nicholson Helen , Sullivan S John
Published: March 2011

Objective

The purpose of this study was to compare the electromyographic (EMG) activity of gluteal and thigh muscles of sportspeople with a recent hamstring injury with uninjured controls during a weight-bearing task.

Study design

Cross-sectional.

Setting

University laboratory.

Participants

16 participants with a hamstring injury (hamstring-injured group, HG) and 18 control participants (control group (CG)) participated in the study.

Main outcome measure

The EMG activity of gluteal, quadriceps and hamstring muscles was recorded during a movement from double- to single-leg movement using surface electrodes.

Results

The EMG onsets of biceps femoris and medial hamstrings were significantly earlier for the HG injured and the uninjured sides in preparation for single-leg standing when compared with the CG average. There were no differences in onsets for the gluteal and quadriceps muscles when comparing the injured or uninjured legs of the HG to the bilateral average of the CG.

Conclusion

The earlier onset of the injured and the uninjured hamstrings in preparation for single leg stance of the HG in comparison with the CG suggests an alteration in the motor control of these muscles. Altered neuromuscular control following a hamstring injury may be a factor to be considered in the rehabilitation of hamstring injuries.
ProducingSalmonella‐free pigs: a review focusing on interventions at weaning
Authors: Wales A. D. , Cook A. J. C. , Davies R. H.
Published: March 2011

Salmonellainfection in pig production is typically endemic and largely asymptomatic. It is a cause of substantial concern among food safety bodies, prompting voluntary and legislative responses aimed at monitoring and reducing the number ofSalmonella‐infected animals entering the human food chain. Elimination of the problem at an early stage of production is highly desirable, and to this end the present review examines published evidence on the carriage ofSalmonellaby piglets before and after weaning, as well as evidence on the dynamics ofSalmonellainfection in the weaner and grower stages of pig production, the effects of maternal immunity, and risk factors forSalmonellaexcretion after weaning. Various interventions to reduce or eliminateSalmonellainfection in young pigs have been tried, such as vaccination, competitive exclusion, treatments in feed and water, antibiotic administration, disinfection of animals, and segregated weaning to clean accommodation. The evidence on the effectiveness of these is considered, and the last is examined in some detail, as it appears currently to offer the best chance of eliminatingSalmonellafrom growing stock.
THE CREATION OF NOVEL AND MARKETABLE SERVICE IDEAS
Authors: CHANG C. M.
Published: March 2011

Novel and marketable service ideas are useful to most service enterprises. However, the literature has identified several reasons for innovations in services as lagging behind those in manufacturing. Some service enterprises believe that service ideas and innovations are readily imitated by competitors. Others view the impact of service innovations on profitability difficult to assess because specific innovative service elements are typically bundled with many other service elements when delivered to or used by customers. Some service enterprises do not have in-house groups specifically dedicated to innovative pursuits, making it difficult for them to systematically produce new service ideas. Furthermore, because services are usually produced and consumed concurrently, any failure tends to expose the service enterprise immediately, unlike the manufacturing companies which can minimize such risks of exposure by conducting pilot testing away from the marketplace. As a result, many service enterprises are said to shy away from aggressively pursuing new service development projects. It does not have to be this way.

This paper describes the combinatorial, heuristic, and normatively guided method, which when correctly applied to a service enterprise enhances the generation of new service ideas in a systematic, speedy, and cost-effective manner, and without requiring the creation of a dedicated and rigid organizational structure. Virtual teams of the "stealth" type are set up to address innovation needs related to marketability and cost competitiveness. These teams may include frontline customer-facing employees as well as customers, suppliers, and other external experts, who can work together despite geographical and time-zone constraints. The application of this method toward developing a specific new service idea is discussed in greater detail.

The integration of a "stealth" team can also be readily applied to the front end of a typical stage-gate service development process, whereby parallel teams are engaged to address critical issues and steps needed to successfully market a service idea before initiating costly development, thereby raising the service enterprises' overall probability of developing commercially successful new services over time.
THE APPLICATION OF REAL OPTIONS THEORY IN DEFENSE R&D PROJECTS: AN EIGHT-FOLD SEQUENTIAL COMPOUND OPTION MODEL
Authors: JANG WON-JOON , LEE JEONG-DONG
Published: March 2011

Today, despite the needs of more credible valuation models in defense research and development (R&D), defense decision makers mainly focus on previous cost and NPV-based approaches to evaluate them. Defense R&D projects should be considered as a sequential compound real option due to its relevant characteristics. This paper presents a real option valuation model with the use of an eight-fold compound option in the valuation of defense R&D projects and its illustrative application using a case study in the Republic of Korea. Compared to the traditional net present value (NPV) methods and their sensitivity analyses with value drivers, the paper shows the necessity of using real option approaches and their mindsets for defense decision makers to decide their defense R&D projects. The contribution of this paper is to present the real option framework in valuating of defense R&D projects, providing for the managerial flexibility with option mindsets. It also shows some limitations of using cost- and NPV-based approaches and presents real options valuation methods as its solution. The paper suggests some feasible defense policy implications that can be applied to the actual process of defense acquisition projects.
LEAN INNOVATION–INTRODUCING VALUE SYSTEMS TO PRODUCT DEVELOPMENT
Authors: SCHUH G. , LENDERS M. , HIEBER S.
Published: March 2011

The implementation of lean thinking in innovation management has not been executed systematically yet. For instance, high uncertainties of processes or limited possibilities for automation in research and development (R&D) indicate special requirements for the implementation of lean thinking. A competitive R&D requires a holistic rethinking for the implementation of lean thinking.

The lean innovation system represents the systematic interpretation of lean thinking principles with reference to product or process innovation and development. One core element of lean innovation is the value system, which is the basis for the value stream design in innovation and development projects. The value system defines, structures and prioritizes "values" adaptively for one specific innovation project. The values are defined by all relevant stakeholders in the innovation and development process, like external and internal customers, considering an organization's strategy and culture. It represents the basis for a consequent value-oriented alignment of project and processes in R&D.

This paper introduces lean innovation and the core findings of the recent survey "Lean innovation" of the Laboratory for Machine Tools and Production Engineering WZL at RWTH Aachen University. Subsequently, the paper focuses on the value system, describes its elements, and shows how to use and benefit from the value system toward a powerful lean innovation.
PMEX — A PERFORMANCE MEASUREMENT EVALUATION MATRIX FOR THE DEVELOPMENT OF INDUSTRIAL SOFTWARE-INTENSIVE PRODUCTS
Authors: CEDERGREN STEFAN , NORSTRÖM CHRISTER , WALL ANDERS
Published: March 2011

The ability to measure performance is both fundamental to and critical in successful product development. Previous research has focused on adding new measurements, not on evaluating those currently used. The performance measurement evaluation matrix (PMEX) is a tool to evaluate the performance-measurement system based on success factors in the development of software-intensive products. Three case studies have been conducted to test the PMEX and the results indicate that the PMEX enables managers to determine explicitly what is and what is not measured. Time, cost, and quality seem to be the focus of the performance measurements while technology and planning activities are absent.
SYNTHESIS, CHARACTERIZATION AND PHOTOCATALYTIC ACTIVITIES OF Ba2YbZrO5.5 NANOPARTICLES UNDER SOLAR IRRADIATION
Authors: KUMAR V. RATHEESH , PRASAD V. S. , WARIAR P. R. S. , KOSHY J.
Published: March 2011

The complex perovskite Ba2YbZrO5.5 has been successfully synthesized as nanoparticles through a single step combustion process for the first time. The X-ray diffraction analysis revealed that the combustion product is phase-pure and has an ordered cubic perovskite structure. Transmission electron microscopy results indicated that the particle sizes are 10–20 nm. The selected area electron diffraction pattern has shown that as-prepared powder is polycrystalline in nature. The UV–visible spectrum analysis confirmed that the optical absorption edge of Ba2YbZrO5.5 is around 340 nm, corresponding to a band gap of ~ 3.65 eV. Photocatalytic activity of Ba2YbZrO5.5 nanoparticles is investigated for the degradation of methyl orange under solar irradiation.
Effects of exercise on VLDL-triglyceride oxidation and turnover
Authors: Sondergaard Esben , Rahbek Iben , Sørensen Lars P. , Christiansen Jens S. , Gormsen Lars C. , Jensen Michael D. , Nielsen Søren
Published: March 2011

Lipids are important substrates for oxidation at rest and during exercise. Aerobic exercise mediates a delayed onset decrease in total and VLDL-triglyceride (TG) plasma concentration. However, the acute effects of exercise on VLDL-TG oxidation and turnover remain unclear. Here, we studied the acute effects of 90 min of moderate-intensity exercise in healthy women and men. VLDL-TG kinetics were assessed using a primed constant infusion of ex vivo labeled [1-14C]triolein VLDL-TG. Fractional VLDL-TG-derived fatty acid oxidation was measured from14CO2specific activity in expired air. VLDL-TG concentration was unaltered during exercise and early recovery, whereas non-VLDL-TG concentration decreased significantly.VLDL-TG secretion rate decreased significantly during exercise and remained suppressed during recovery. Total VLDL-TG oxidation rate was unaffected by exercise. However, the contribution of VLDL-TG oxidation to total energy expenditure fell from 14 ± 9% at rest to 3 ± 4% during exercise. We conclude that VLDL-TG fatty acids are quantitatively important oxidative substrates under basal postabsorptive conditions but remain unaffected during 90-min moderate-intensity exercise and, thus, become relatively less important during exercise. Lower VLDL secretion rate during exercise may contribute to the decrease in TG concentrations during and after exercise.
Continuous 24-h nicotinic acid infusion in rats causes FFA rebound and insulin resistance by altering gene expression and basal lipolysis in adipose tissue
Authors: Oh Young Taek , Oh Ki-Sook , Choi Yong Min , Jokiaho Anne , Donovan Casey , Choi Sangdun , Kang Insug , Youn Jang H.
Published: March 2011

Nicotinic acid (NA) has been used as a lipid drug for five decades. The lipid-lowering effects of NA are attributed to its ability to suppress lipolysis in adipocytes and lower plasma FFA levels. However, plasma FFA levels often rebound during NA treatment, offsetting some of the lipid-lowering effects of NA and/or causing insulin resistance, but the underlying mechanisms are unclear. The present study was designed to determine whether a prolonged, continuous NA infusion in rats produces a FFA rebound and/or insulin resistance. NA infusion rapidly lowered plasma FFA levels (>60%, P < 0.01), and this effect was maintained for ≥5 h. However, when this infusion was extended to 24 h, plasma FFA levels rebounded to the levels of saline-infused control rats. This was not due to a downregulation of NA action, because when the NA infusion was stopped, plasma FFA levels rapidly increased more than twofold ( P < 0.01), indicating that basal lipolysis was increased. Microarray analysis revealed many changes in gene expression in adipose tissue, which would contribute to the increase in basal lipolysis. In particular, phosphodiesterase-3B gene expression decreased significantly, which would increase cAMP levels and thus lipolysis. Hyperinsulinemic glucose clamps showed that insulin's action on glucose metabolism was improved during 24-h NA infusion but became impaired with increased plasma FFA levels after cessation of NA infusion. In conclusion, a 24-h continuous NA infusion in rats resulted in an FFA rebound, which appeared to be due to altered gene expression and increased basal lipolysis in adipose tissue. In addition, our data support a previous suggestion that insulin resistance develops as a result of FFA rebound during NA treatment. Thus, the present study provides an animal model and potential molecular mechanisms of FFA rebound and insulin resistance, observed in clinical studies with chronic NA treatment.
Muc17 protects intestinal epithelial cells from enteroinvasive E. coli infection by promoting epithelial barrier integrity
Authors: Resta-Lenert Silvia , Das Srustidhar , Batra Surinder K. , Ho Samuel B.
Published: March 2011

The membrane-bound mucin MUC17 (mouse homolog Muc3) is highly expressed on the apical surface of intestinal epithelia and is thought to play a role in epithelial restitution and protection. Therefore, we hypothesized that MUC17 has a role in protection of the intestinal mucosa against luminal pathogens. Human intestinal cell lines were transfected by electroporation (Caco-2 and HT 29/19A) and by retroviral expression vector (LS174T, a cell line with high levels of MUC17 expression) using MUC17 siRNA. Transepithelial electrical resistance, permeability, tight-junction protein expression, adhesion, and invasion in response to enteroinvasive Escherichia coli (EIEC) were measured in all cell lines. In some experiments, the effect of the addition of exogenous purified crude mucin or recombinant Muc3 cysteine-rich domain protein (Muc3 CRD1-L-CRD2) as preventative or protective treatment was tested. Reduction of endogenous MUC17 is associated with increased permeability, inducible nitric oxide synthase and cyclooxygenase 2 induction, and enhanced bacterial invasion in response to EIEC exposure. Bacterial adhesion is not affected. Exogenous mucin (Muc3) and recombinant Muc3CRD treatment had a small but significant effect in attenuating the effects of EIEC infection. In conclusion, these data suggest that both native and exogenous MUC17 play a role in attachment and invasion of EIEC in colonic cell lines and in maintaining epithelial barrier function.
Hydrogen sulfide is a partially redox-independent activator of the human jejunum Na+ channel, Nav1.5
Authors: Strege Peter R. , Bernard Cheryl E. , Kraichely Robert E. , Mazzone Amelia , Sha Lei , Beyder Arthur , Gibbons Simon J. , Linden David R. , Kendrick Michael L. , Sarr Michael G. , Szurszewski Joseph H. , Farrugia Gianrico
Published: March 2011

Hydrogen sulfide (H2S) is produced endogenously by l-cysteine metabolism. H2S modulates several ion channels with an unclear mechanism of action. A possible mechanism is through reduction-oxidation reactions attributable to the redox potential of the sulfur moiety. The aims of this study were to determine the effects of the H2S donor NaHS on NaV1.5, a voltage-dependent sodium channel expressed in the gastrointestinal tract in human jejunum smooth muscle cells and interstitial cells of Cajal, and to elucidate whether H2S acts on NaV1.5 by redox reactions. Whole cell Na+ currents were recorded in freshly dissociated human jejunum circular myocytes and NaV1.5-transfected human embryonic kidney-293 cells. RT-PCR amplified mRNA for H2S enzymes cystathionine β-synthase and cystathionine γ-lyase from the human jejunum. NaHS increased native Na+ peak currents and shifted the half-point ( V1/2) of steady-state activation and inactivation by +21 ± 2 mV and +15 ± 3 mV, respectively. Similar effects were seen on the heterologously expressed NaV1.5 α subunit with EC50s in the 10−4 to 10−3 M range. The reducing agent dithiothreitol (DTT) mimicked in part the effects of NaHS by increasing peak current and positively shifting steady-state activation. DTT together with NaHS had an additive effect on steady-state activation but not on peak current, suggesting that the latter may be altered via reduction. Pretreatment with the Hg2+-conjugated oxidizer thimerosal or the alkylating agent N-ethylmaleimide inhibited or decreased NaHS induction of NaV1.5 peak current. These studies show that H2S activates the gastrointestinal Na+ channel, and the mechanism of action of H2S is partially redox independent.
Exercise-induced cardiac preconditioning: how exercise protects your achy-breaky heart
Authors: Frasier Chad R. , Moore Russell L. , Brown David A.
Published: March 2011

The ability of exercise to protect the heart against ischemia-reperfusion (I/R) injury is well known in both human epidemiological studies and experimental animal models. In this review article, we describe what is currently known about the ability of exercise to precondition the heart against infarction. Just 1 day of exercise can protect the heart against ischemia/reperfusion damage, and this protection is upheld with months of exercise, making exercise one of the few sustainable preconditioning stimuli. Exercise preconditioning depends on the model and intensity of exercise, and appears to involve heightened oxidant buffering capacity, upregulated subunits of sarcolemmal ATP-sensitive potassium channels, and adaptations to cardiac mitochondria. We review the putative mechanisms involved in exercise preconditioning and point out many areas where future research is necessary to advance our understanding of how this stimulus confers resistance against I/R damage.
Distinct fast and slow processes contribute to the selection of preferred step frequency during human walking
Authors: Snaterse Mark , Ton Robert , Kuo Arthur D. , Donelan J. Maxwell
Published: March 2011

Humans spontaneously select a step frequency that minimizes the energy expenditure of walking. This selection might be embedded within the neural circuits that generate gait so that the optimum is pre-programmed for a given walking speed. Or perhaps step frequency is directly optimized, based on sensed feedback of energy expenditure. Direct optimization is expected to be slow due to the compounded effect of delays and iteration, whereas a pre-programmed mechanism presumably allows for faster step frequency selection, albeit dependent on prior experience. To test for both pre-programmed selection and direct optimization, we applied perturbations to treadmill walking to elicit transient changes in step frequency. We found that human step frequency adjustments ( n = 7) occurred with two components, the first dominating the response (66 ± 10% of total amplitude change; mean ± SD) and occurring quite quickly (1.44 ± 1.14 s to complete 95% of total change). The other component was of smaller amplitude (35 ± 10% of total change) and took tens of seconds (27.56 ± 16.18 s for 95% completion). The fast process appeared to be too fast for direct optimization and more indicative of a pre-programmed response. It also persisted even with unusual closed-loop perturbations that conflicted with prior experience and rendered the response energetically suboptimal. The slow process was more consistent with the timing expected for direct optimization. Our interpretation of these results is that humans may rely heavily on pre-programmed gaits to rapidly select their preferred step frequency and then gradually fine-tune that selection with direct optimization.
Muscle fatigue-induced enhancement of corticomuscular coherence following sustained submaximal isometric contraction of the tibialis anterior muscle
Authors: Ushiyama Junichi , Katsu Masanori , Masakado Yoshihisa , Kimura Akio , Liu Meigen , Ushiba Junichi
Published: March 2011

Oscillatory activity of the sensorimotor cortex shows coherence with muscle activity within the 15- to 35-Hz frequency band (β-band) during weak to moderate sustained isometric contraction. We aimed to examine the acute changes in this corticomuscular coupling due to muscle fatigue and its effect on the steadiness of the exerted force. We quantified the coherence between the electroencephalogram (EEG) recorded over the sensorimotor cortex and the rectified surface electromyogram (EMG) of the tibialis anterior muscle as well as the coefficient of variance of the dorsiflexion force (ForceCV) and sum of the auto-power spectral density function of the force within the β-band (Forceβ-PSD) during 30% of maximal voluntary contraction (MVC) for 60 s before (prefatiguing task) and after (postfatiguing task) muscle fatigue induced by sustained isometric contraction at 50% of MVC until exhaustion in seven healthy male subjects. The magnitude of the EEG-EMG coherence increased in the postfatiguing task in six of seven subjects. The maximal peak of EEG-EMG coherence stayed within the β-band in both pre- and postfatiguing tasks. Interestingly, two subjects, who had no significant EEG-EMG coherence in the prefatiguing task, showed significant coherence in the postfatiguing task. Additionally, ForceCV and Forceβ-PSD significantly increased after muscle fatigue. These data suggest that when muscle fatigue develops, the central nervous system enhances oscillatory muscular activity in the β-band stronger coupled with the sensorimotor cortex activity accomplishing the sustained isometric contraction at lower performance levels.
Adenosine 5′-monophosphate challenge elicits a more peripheral airway response than methacholine challenge
Authors: Michils Alain , Elkrim Yvon , Haccuria Amaryllis , Van Muylem Alain
Published: March 2011

Adenosine 5′-monophosphate (AMP) and methacholine are commonly used to assess airway hyperreactivity. However, it is not fully known whether the site of airway constriction primarily involved during challenges with either agent is similar. Using a ventilation distribution test, we investigated whether the constriction induced by each agent involves the lung periphery in a similar fashion. Ventilation distribution was evaluated by the phase III slope (S) of the single-breath washout, using gases with different diffusivities like helium (He) and hexafluorosulfur (SF6). A greater postchallenge increase in SHe reflects alterations at the level of terminal and respiratory bronchioles, while a greater increase in SSF6 reflects alterations in alveolar ducts, increases to an equal extent reflecting alterations in more proximal airways where gas transport is still convective for both gases. SSF6 and SHe were measured in 15 asthma patients before and after airway challenges (20% forced expired volume in 1-s fall) with AMP and methacholine. SHe increased to a greater extent than SSF6 after AMP challenge (5.7 vs. 3.7%/l; P = 0.002), with both slopes increasing to an equal extent after methacholine challenge (3.1%/l; P = 0.959). The larger increase in SHe following AMP challenge suggests distal ventilation impairment up to the level of terminal and respiratory bronchioles. With methacholine, the similar increases in SHe and SSF6 suggest a less distal impairment. AMP, therefore, seems to affect more extensively the very peripheral airways, whereas methacholine seems to have an effect on less distal airways.
Electroacupuncture reduces the evoked responses of the spinal dorsal horn neurons in ankle-sprained rats
Authors: Kim Jae Hyo , Kim Hee Young , Chung Kyungsoon , Chung Jin Mo
Published: March 2011

Acupuncture is shown to be effective in producing analgesia in ankle sprain pain in humans and animals. To examine the underlying mechanisms of the acupuncture-induced analgesia, the effects of electroacupuncture (EA) on weight-bearing forces (WBR) of the affected foot and dorsal horn neuron activities were examined in a rat model of ankle sprain. Ankle sprain was induced manually by overextending ligaments of the left ankle in the rat. Dorsal horn neuron responses to ankle movements or compression were recorded from the lumbar spinal cord using an in vivo extracellular single unit recording setup 1 day after ankle sprain. EA was applied to the SI-6 acupoint on the right forelimb (contralateral to the sprained ankle) by trains of electrical pulses (10 Hz, 1-ms pulse width, 2-mA intensity) for 30 min. After EA, WBR of the sprained foot significantly recovered and dorsal horn neuron activities were significantly suppressed in ankle-sprained rats. However, EA produced no effect in normal rats. The inhibitory effect of EA on hyperactivities of dorsal horn neurons of ankle-sprained rats was blocked by the α-adrenoceptor antagonist phentolamine (5 mg/kg ip) but not by the opioid receptor antagonist naltrexone (10 mg/kg ip). These data suggest that EA-induced analgesia in ankle sprain pain is mediated mainly by suppressing dorsal horn neuron activities through α-adrenergic descending inhibitory systems at the spinal level.
Cathodal transcranial direct current stimulation suppresses ipsilateral projections to presumed propriospinal neurons of the proximal upper limb
Authors: Bradnam Lynley V. , Stinear Cathy M. , Byblow Winston D.
Published: March 2011

This study investigated whether cathodal transcranial direct current stimulation (c-tDCS) of left primary motor cortex (M1) modulates excitability of ipsilateral propriospinal premotoneurons (PNs) in healthy humans. Transcranial magnetic stimulation (TMS) of the right motor cortex was used to obtain motor evoked potentials (MEPs) from the left biceps brachii (BB) while participants maintained contraction of the left BB. To examine presumed PN excitability, left BB MEPs were compared with those conditioned by median nerve stimulation (MNS) at the left elbow. Interstimulus intervals between TMS and MNS were set to produce summation at the C3–C4 level of the spinal cord. MNS facilitated BB MEPs elicited at TMS intensities near active motor threshold but inhibited BB MEPs at slightly higher intensities, indicative of putative PN modulation. c-tDCS suppressed the facilitatory and inhibitory effects of MNS. Sham tDCS did not alter either component. There was no effect of c-tDCS and sham tDCS on nonconditioned left BB MEPs or on the ipsilateral silent period of left BB. Right first dorsal interosseous MEPs were suppressed by c-tDCS. These results indicate that M1 c-tDCS can be used to modulate excitability of ipsilateral projections to presumed PNs controlling the proximal arm muscle BB. This technique may hold promise for promoting motor recovery of proximal upper limb function after stroke.
Combined Electrostatic-Covalent Building of Au NPs Multilayers and Their Size-Enhanced Cohesive and SERS Properties
Authors: Mougin K. , Darwich S. , Vidal L. , Haidara H.
Published: March 2011

Multilayers of well-ordered and close-packed 2D nanostructures of gold nanoparticles (NPs) were fabricated using a layer-by-layer technique. Colloidal spherical Au NPs of 5 and 15 nm diameters were synthesized and, respectively, self-assembled in multilayers. The robustness of these systems was insured by a combination of electrostatic and covalent bonds between nanoparticles and linker molecules. The compacity of the superlattice was characterized by AFM observation and ellipsometry measurements. Evidence of stronger cohesion of multilayers of smaller NPs size was brought by submitting the systems to sonication test. The multilayers have also proved analytical potential when used to detect low concentration methylene blue molecules adsorbed on the Au nanoparticles, by surface-enhanced Raman spectroscopy (SERS). The detection sensitivity of these two sized Au NPs architectures was directly compared to an evaporated “bulk” Au thin film of equivalent thickness. Results have displayed a strong increase of the electromagnetic field enhancement with a decrease of the NPs size, whereas the bulk thin Au film was shown to be inefficient as a SERS substrate. These results bring a nice evidence of size effects on the global performance (SERS, cohesion) and hopefully on the stability of NPs based nanostructures.
Pathogens, Social Networks, and the Paradox of Transmission Scaling
Authors: Ferrari Matthew J. , Perkins Sarah E. , Pomeroy Laura W. , Bjørnstad Ottar N.
Published: March 2011

Understanding the scaling of transmission is critical to predicting how infectious diseases will affect populations of different sizes and densities. The two classic “mean-field” epidemic models—either assuming density-dependent or frequency-dependent transmission—make predictions that are discordant with patterns seen in either within-population dynamics or across-population comparisons. In this paper, we propose that the source of this inconsistency lies in the greatly simplifying “mean-field” assumption of transmission within a fully-mixed population. Mixing in real populations is more accurately represented by a network of contacts, with interactions and infectious contacts confined to the local social neighborhood. We use network models to show that density-dependent transmission on heterogeneous networks often leads to apparent frequency dependency in the scaling of transmission across populations of different sizes. Network-methodology allows us to reconcile seemingly conflicting patterns of within- and across-population epidemiology.
Modeling and Simulation of a Chemical Vapor Deposition
Authors: Geiser J. , Arab M.
Published: March 2011

We are motivated to model PE‐CVD (plasma enhanced chemical vapor deposition) processes for metallic bipolar plates, and their optimization for depositing a heterogeneous layer on the metallic plate. Moreover a constraint to the deposition process is a very low pressure (nearly a vacuum) and a low temperature (about 400 K). The contribution of this paper is to derive a multiphysics system of multiple physics problems that includes some assumptions to simplify the complicate
process and allows of deriving a computable mathematical model without neglecting the real‐life processes.
To model the gaseous transport in the apparatus we employ mobile gas phase streams, immobile and mobile phases in a chamber that is filled with porous medium (plasma layers). Numerical methods are discussed to solve such multi‐scale and multi phase models and to obtain qualitative results for the delicate multiphysical processes in the chamber. We discuss a splitting analysis to couple such multiphysical problems. The verification of such a complicated model is done with real‐life experiments
for single species. Such numerical simulations help to economize on expensive physical experiments and obtain control mechanisms for the delicate deposition process.
Connexin-26 Is a Key Factor Mediating Gemcitabine Bystander Effect
Authors: Garcia-Rodríguez Laura , Pérez-Torras Sandra , Carrió Meritxell , Cascante Anna , García-Ribas Ignacio , Mazo Adela , Fillat Cristina
Published: March 2011

Gemcitabine is a nucleoside analogue with anticancer activity. Inside the cell, it is sequentially phosphorylated to generate the active drug. Phosphorylated nucleoside analogues have been shown to traffic through gap junctions. We investigated the participation of gap junctional intercellular communication (GJIC) as a possible mechanism spreading gemcitabine cytotoxicity in pancreatic tumors. Immunohistochemical analysis of pancreatic cancer biopsies revealed increased connexin 26 (Cx26) content but loss of connexins 32 (Cx32) and 43 (Cx43) expression. Cx26 abundance in neoplastic areas was confirmed by Cx26 mRNA in situ hybridization. Heterogeneity on the expression levels and the localization of Cx26, Cx32, and Cx43 were identified in pancreatic cancer cells and found to be associated with the extent of GJIC, and correlated with gemcitabine bystander cytotoxic effect. The abundance of Cx26 at the contact points in tumoral regions prompted us to study the involvement of Cx26 in the GJIC of gemcitabine toxic metabolites and their influence on the antitumoral effects of gemcitabine. Knockdown of Cx26 led to decreased GJIC and reduced gemcitabine bystander killing whereas overexpression of Cx26 triggered increased GJIC and enhanced the gemcitabine cytotoxic bystander effect. Gemcitabine treatment of mice bearing tumors, with a high GJIC capacity, resulted in a significant delay in tumor progression. Interestingly, gemcitabine administration in mice bearing tumors that overexpress Cx26 triggered a dramatic tumor regression of 50% from the initial volume. This study shows that Cx26 participates in the gap junction–mediated bystander cytoxic effect of gemcitabine and provides evidence that upregulation of Cx26 improves gemcitabine anticancer efficacy. Mol Cancer Ther; 10(3); 505–17. ©2011 AACR.
Complex Split Cord Malformation with Mediastinal Extension of a Teratoma and Simultaneous Ventral and Dorsal Bony Spur Splitting the Cord
Authors: Naik Vikas , Mahapatra Ashok Kumar , Gupta Chaitali , Suri Vaishali
Published: March 2011

Introduction: Association of split cord malformation with teratoma is an extremely rare condition. It is very unusual to find split cord malformation with teratomas extending into the posterior mediastinum and still rarer to find bony spur arising dorsally and ventrally at the same level. Case Report: The authors describe the case of a 2-year-old child who presented with dorsal kyphosis and a dermal sinus. The neurological examination was unremarkable. MRI and noncontrast CT of the spine revealed Pang’s type I split cord malformation at the D9–12 level. Bony spur was seen arising both dorsally and ventrally at the D9–12 level. Intraoperatively, intradural teratoma was found coming extradurally both posteriorly between the 2 spurs and anteriorly into the posterior mediastinum above the bony spurs through a defect in the vertebral body of 2 cm diameter. Near total excision was performed. Discussion: To the best of the authors’ knowledge, this is the second case report of an intradural teratoma extending into the mediastinum, occurring with split cord malformations and other spinal anomalies. A similar case was reported from our institute in 2006. This is the first report of its kind of simultaneous dorsal and ventral bony spur at the same level.
The Necessity for Effective Interaction between Basic Scientists and Rehabilitation Clinicians
Authors: Segal Richard L. , Lewek Michael D. , McCulloch Karen , Mercer Vicki S.
Published: March 2011

Important basic science research is being conducted that has direct implications for the rehabilitation of patients, but the translation of this research to change clinical practice does not occur automatically. Advisory panels to the National Center for Medical Rehabilitation Research acknowledge a need for basic and applied research related to the factors underlying coordinated movements, such as the interactions of the neuromuscular and musculoskeletal systems. In this paper, we briefly describe recent studies that have examined the preceding interaction and discuss some basic issues related to the translation of these experiments to the clinic. More importantly, the main purpose of this paper is to discuss models/ways to translate basic science to clinical practice in a two-way and informed interaction between basic scientists and clinicians.
Management of the 2009 A/H1N1 Influenza Pandemic in Patients with Hematologic Diseases: A Prospective Experience at an Italian Center
Authors: Girmenia Corrado , Mercanti Caterina , Federico Vincenzo , Rea Massimiliano , De Vellis Annalisa , Valle Veronica , Micozzi Alessandra , Latagliata Roberto , Breccia Massimo , Morano Salvatore Giacomo , Brunetti Gregorio Antonio , Sali Michela , Delogu Giovanni , Foà Robin , Alimena Giuliana , Gentile Giuseppe
Published: March 2011

Data derived from epidemiologic surveillance adopted at our center in hematologic and stem cell transplant patients during the 2009 influenza A (H1N1)v pandemic are reported. Of the 52 patients with influenza-like disease we observed, 37 underwent a real-time PCR evaluation and 21 had a confirmed diagnosis. Of the RT-PCR-confirmed cases, 23.8% were children (age <18 years) and 9.5% were >65 years; 47.6% presented with a pulmonary infiltrate and 33.3% with respiratory failure. Pulmonary involvement was observed more frequently in patients with comorbidities. All patients received a course of oseltamivir therapy starting an average of 1 day (range <1–2) after the onset of symptoms. No patient was transferred to the intensive care unit. The viral disease had a generally favorable outcome despite the high frequency of pulmonary involvement. A prompt clinical evaluation with an early antiviral and supportive therapy may have played a beneficial role in the outcome.
Major Histocompatibility Complex Class-I-Interacting Natural Killer Cell Receptors of Nonhuman Primates
Authors: Walter Lutz
Published: March 2011

Human natural killer (NK) cell receptors are known to be highly polymorphic, to show complex genetics and to be associated with susceptibility to a variety of immunological diseases. Nonhuman primates are used as important models of these diseases, yet the knowledge of nonhuman primate NK cell receptors and ligands is not as advanced as in humans. Recently published data indicated that diversity and polymorphism of NK cell receptors are similar between nonhuman primates and humans. Comparative genomics revealed instructive insights into the evolution and function of primate NK cell receptor genes and contributed to the understanding of how present-day NK cell receptors and their ligands have evolved. Here, I review the current knowledge of nonhuman primate NK cell receptors that interact with major histocompatibility complex class I proteins.
Natural Killer Cell Responses to Infections in Early Life
Authors: Guilmot Aline , Hermann Emmanuel , Braud Véronique M. , Carlier Yves , Truyens Carine
Published: March 2011

Natural killer (NK) cells are an important component of innate immune responses to infectious diseases. They mediate protection by being able to rapidly lyse infected cells and produce cytokines (primarily interferon-γ) that shape innate and adaptive immune responses. This review summarizes current knowledge on the phenotype and functional abilities of NK cells from healthy newborns/infants and on NK cell responses against viral, bacterial and protozoan infections in early life. Interestingly, NK cell blood counts are higher in newborns than in adults but they do not display striking differences in phenotype, except for an increased frequency of expression of the inhibitory CD94/NKG2A receptor. They display some inherent functional defects, mainly a lower cytolytic capacity that may contribute to the immaturity of the neonatal immune system. Changes in circulating levels of NK cells observed during pediatric infections and the ability of NK cells from newborns and children to produce interferon-γ at the encounter with pathogens indicate that NK cells participate in the immune response to infectious diseases in early life. Unfortunately, information is currently insufficient to assess whether these NK cell responses really contribute to control infections, either vertically transmitted or acquired in infancy.
Natural Killer Cell Responses to Viral Infection
Authors: Brandstadter Joshua D. , Yang Yiping
Published: March 2011

Natural killer (NK) cells, as part of the innate immune system, play a key role in host defense against viral infections. Recent advances have indicated that NK cell activation and function are regulated by the interplay between inhibitory and activating signals. Thus, a better understanding of mechanisms responsible for NK cell activation and function in the control of viral infections will help develop NK cell-based therapies. In this review, we will first discuss how NK cells are activated in response to viral infections. We will then focus on the recruitment of activated NK cells to the site of infection as well as on NK cell effector mechanisms against virally infected cells.
Increased Serum Levels of Oxidative Stress Are Associated with Hospital Readmissions due to Acute Heart Failure
Authors: Rogowski Ori , Shnizer Sergei , Wolff Rafael , Lewis Basil S. , Amir Offer
Published: March 2011

Objectives: Inflammation and serum oxidative stress (OS) are important components in heart failure (HF) deterioration. In this study we tested the hypothesis that an increase in patients’ sera OS levels is associated with acute HF (AHF) readmissions. Methods: Thirty consecutive patients (mean age 71 ± 10 years) admitted with AHF were included in the study. Serum OS in these patients was measured in-hospital and repeatedly after discharge over a period of 8 weeks of follow-up in which we reordered patients’ HF readmissions. Of the 30 patients, 13 (43%) were readmitted (RAD group) and 17 (57%) did not require readmission (NRAD group). Results: OS levels before discharge from the first hospital admission in the 2 groups were similar (p = 0.84 and p = 0.56, respectively). However, using repeated measures ANOVA, we found that the interaction between the time points and the 2 groups of patients (RAD and NRAD) was statistically significant (p = 0.037). It is important to note that OS serum levels were more predictive of HF readmissions than were repeated simultaneous serum measurements of NT-proBNP (p = 0.97). Conclusions: Increased OS levels in AHF patients, after they have been discharged from the hospital, are associated with higher HF readmission rates. In AHF, OS is a dynamic parameter associated with HF deterioration.
Fifty-kDa Hyaluronic Acid Upregulates Some Epidermal Genes without Changing TNF-α Expression in Reconstituted Epidermis
Authors: Farwick M. , Gauglitz G. , Pavicic T. , Köhler T. , Wegmann M. , Schwach-Abdellaoui K. , Malle B. , Tarabin V. , Schmitz G. , Korting H.C.
Published: March 2011

Background: Due to its strong water binding potential, hyaluronic acid (HA) is a well-known active ingredient for cosmetic applications. However, based on its varying molecular size, skin penetration of HA may be limited. Recent studies have demonstrated that low-molecular-weight HA (LMW HA) may show a certain proinflammatory activity. We thus aimed to characterize an LMW-sized HA molecule that combines strong anti-aging abilities with efficient skin penetration but lacks potential proinflammatory effects. Methods: Total RNA and total protein were isolated from reconstituted human epidermis following incubation with HAs of various molecular weights (20, 50, 130, 300, 800 and 1,500 kDa). Tumor necrosis factor-α expression was determined using quantitative PCR. Genomic and proteomic expression of various junctional proteins was determined using Affymetrix and common Western blotting techniques. Results: LMWHA of approximately 50 kDa did not significantly alter tumor necrosis factor-α expression compared to 20-kDa HA, but revealed significantly higher skin penetration rates than larger sized HA associated with increased expression of genes and proteins known to be involved in tight junction formation and keratinocyte cohesion. Conclusion: LMW HA of approximately 50 kDa shows better penetration abilities than larger-sized HA. In addition, LMW HA influences the expression of various genes including those contributing to keratinocyte differentiation and formation of intercellular tight junction complexes without showing proinflammatory activity. These observations contribute to current knowledge on the effects of LMW HA on keratinocyte biology and cutaneous physiology.
Effective Management of Acute Coronary Thrombosis in a Young Woman with Lupus Using Aggressive Medical Therapy
Authors: Patel Parin J. , Matthai, Jr. William H. , Untereker William J.
Published: March 2011

Systemic lupus erythematosus is a chronic inflammatory disorder that predisposes to acute coronary thrombosis. To demonstrate how the pathophysiology of lupus-mediated coronary events may be unique, we offer the case and management of a young woman with lupus who presented with acute myocardial infarction. She was initially managed with medical therapy including the standard regimen of aspirin, heparin, and clopidogrel. Despite a Thrombolysis in Myocardial Infarction risk score of only 2, she was also given eptifibatide infusion because of clinical concerns. Repeated cardiac catheterization showed marked regression of the thrombus, and coronary fractional flow reserve calculation demonstrated full recovery of coronary vasculature with this therapy. This case demonstrates effective management of life-threatening coronary thrombosis with medical therapy only in a young woman with lupus. We briefly review the pathophysiology of acute coronary thrombosis in lupus patients and distinguish this from the more common process of age-related atherosclerosis. Given the lack of evidence in this specific population, we discuss a pathophysiology-based clinical decision-making tool. Assessing clinical risk factors and using technologies such as intravascular ultrasound can help make the correct treatment decision.
The Role of Natural Killer Cells in Human Solid Organ and Tissue Transplantation
Authors: Villard Jean
Published: March 2011

During the last decade, considerable progress was made in the understanding of the natural killer (NK) cell mechanisms of action, especially in the processes of target cell recognition and lysis. These breakthroughs have aroused large interest in the role of NK cells in the pathogenesis of a variety of diseases. In hematopoietic stem cell transplantation, NK cells have been shown to play a significant role in the graft-versus-leukemic effect leading to protocols of cell therapy using amplified NK cells after transplantation. In human solid organ transplantation (SOT), the role of NK cells was controversial due to conflicting clinical and animal model data. NK cells have been shown to exacerbate T-cell responses during rejection, but also to promote tolerance induction under immunosuppression. The role of NK cells is of special interest in SOT because in contrast to T cells, the effect of immunosuppressive drugs on NK cells is modest, at least in vivo. Recent publications demonstrated the importance of killer cell immunoglobulin-like receptor/human leukocyte antigen genotypes to predict the risk of rejection and to prevent cytomegalovirus infection/reactivation. NK cell subpopulations could have different alloreactivity or immunomodulatory potentials. Finally, an understanding of the role of NK cells in the field of embryonic stem cells and their progenitor transplantation is developing. Currently, NK cells are considered a key player in the alloimmune and anti-infectious responses after SOT and transplanted tissues.