bluuebunny/crossref_metadata_2025 huggingface dataset:
The morphology and properties of melt-mixed polyoxymethylene/monosilanolisobutyl-POSS composites
Authors: Illescas Silvia , Sánchez-Soto Miguel , Milliman Henry , Schiraldi David A. , Arostegui Asier
Published: August 2011

In this study, the morphology and thermo-mechanical behavior of composites formed by a polyoxymethylene (POM) matrix and monosilanolisobutyl polyhedral oligomeric silsesquioxane (msib-POSS) filler have been studied. The msib-POSS molecules were added to the POM by direct melt blending at loadings between 0 and 10 wt.%. Hydrogen bonding interactions were detected between POM and msib-POSS Si-OH groups, increasing their mutual compatibility and leading to nanometer-size dispersion of some msib-POSS molecules. These interactions do not prevent POSS aggregation during blending, but lead to micron-scale msib-POSS domains. The thermal decomposition temperature of the composites remained practically constant under inert and oxidative conditions. The low temperature thermal transition (γ) and glass transition temperature ( Tg) of POM were found to move to higher temperatures only when 2.5 wt.% of msib-POSS was added, indicating that POSS is physically linked to the POM chains, restricting their motion under those conditions. Low content (2.5 wt.%) of msib-POSS results in antiplastization, whereas higher levels of POSS lead to a decrease in the storage modulus of the polymer. The relationships among these effects and the morphological characteristics of the systems will be discussed herein.
Airfoil Structural Morphing Based on S.M.A. Actuator Series: Numerical and Experimental Studies
Authors: Barbarino S. , Pecora R. , Lecce L. , Concilio A. , Ameduri S. , De Rosa L.
Published: August 2011

Multiple flight regimes during typical aircraft missions mean that a single unique optimized configuration, that maximizes aerodynamic efficiency and maneuverability, cannot be defined. Discrete components such as ailerons and flaps provide some adaptability, although they are far from optimal. Wing morphing can significantly improve the performance of future aircraft, by adapting the wing shape to the specific flight regime requirements, but also represents a challenging problem: the structure has to be stiff to maintain its shape under loads, and yet be flexible to deform without collapse. One solution is to adopt structural elements made of smart materials; Shape Memory Alloys (SMAs) have demonstrated their suitability for many static applications due to their high structural integration potential and remarkable actuation capabilities.

In this work, the airfoil camber at the wing trailing edge on a full scale wing of a civil regional transportation aircraft is controlled by substituting a traditional split flap with a hingeless, smooth morphed flap. Firstly, the development and testing of an actuator device based on a SMA ribbon, capable of a net rotation of 5 deg, is presented. Then, a flap bay is designed and experimentally tested in presence of static loads, based on a compliant rib built as a series repetition of the proposed actuator. An aero-thermo-mechanical simulation within a FE approach was adopted to estimate the behavior and performance of the compliant rib, integrating both aerodynamic loads, by means of a Vortex Lattice Method (VLM) code, and SMA phenomenology, implementing Liang and Rogers’ constitutive model. The prototype showed good actuation performance even in presence of external loads. Very good numerical-experimental correlation is found for the unloaded case, while some fatigue issues emerged in presence of static loads.
Concomitant Forms of Abuse and Help-Seeking Behavior Among White, African American, and Latina Women Who Experience Intimate Partner Violence
Authors: Flicker Sharon M. , Cerulli Catherine , Zhao Xi , Tang Wan , Watts Arthur , Xia Yinglin , Talbot Nancy L.
Published: August 2011

This study uses National Violence against Women Survey data to investigate the differential impact of concomitant forms of violence (sexual abuse, stalking, and psychological abuse) and ethnicity on help-seeking behaviors of women physically abused by an intimate partner ( n = 1,756). Controlling for severity of the physical abuse, women who experienced concomitant sexual abuse are less likely to seek help, women who experienced concomitant stalking are more likely to seek help, whereas concomitant psychological abuse is not associated with help seeking. Ethnic differences are found in help seeking from friends, mental health professionals, police, and orders of protection. Implications for service outreach are discussed.
Effect of Acetylcholine on Mitogen Response of Peripheral Lymphocytes Isolated From Rats Exposed to Chronic Stress
Authors: Ono Makiko , Okada Shinobu
Published: August 2011

The purpose of this study was to clarify the effects of acetylcholine (Ach) on lymphocyte function in rats under chronic stress. The authors isolated peripheral lymphocytes from rats 5 weeks after stress treatment and then measured interleukin-2 (IL-2) production after stimulation with concanavalin A or phytohemagglutinin-L. Although mitogen-induced IL-2 production of the stress group was lower than that of the control group, the addition of Ach significantly increased mitogen-induced IL-2 production in both groups. This effect of Ach was inhibited by atropine in the control group only. The changes (increasing rates) in mitogen-induced IL-2 production from basal condition showed a negative correlation with serum corticosterone concentrations. The authors observed no correlation between the effects of Ach (changes in mitogen-induced IL-2 production with Ach compared to those without Ach) and serum corticosterone concentration. These findings suggest that stimulation of the parasympathetic nervous system improves lymphocyte function during chronic stress.
Methodological Issues for Studying the Rest–Activity Cycle and Sleep Disturbances
Authors: Calogiuri Giovanna , Weydahl Andi , Carandente Franca
Published: August 2011

Shift work schedules, intensive physical exercise late in the day, psychological stress, or a busy lifestyle might induce disorders of the circadian structure, which can affect health on both the physiological and neurobehavioral levels. Rest–activity rhythm is strongly connected with an organism’s circadian structure, and irregular sleep–wake patterns can lead to a disruption of entrainment, resulting in physiological and neurobehavioral dysfunction. Shift nurses are often subject to disturbances in the quality and duration of their sleep, raising the possibility of negative impacts on their health and their patients' safety. Researchers have used actigraphy in a number of studies to assess sleep patterns. Because of the close connection between sleep and circadian structure, it may be useful to extend the evaluation of actigraphy data to the analysis of the rest–activity rhythm with rhythmometric procedures to provide a better understanding of possible sleep disorders in relation to entrainment. Actigraphy is an easy and reliable way to study these rhythms and identify possible circadian-rhythm disorders. In this article, the authors discuss methodological issues concerning the evaluation of the rest–activity rhythm, with a focus on actigraphy.
Interleukin-10 Predicts Preterm Birth in Acculturated Hispanics
Authors: Wommack Joel C. , Ruiz R. Jeanne , Marti C. Nathan , Stowe Raymond P. , Brown Charles E. L. , Murphey Christina
Published: August 2011

Objective:

Among Hispanics living in the United States, acculturation is associated with an increased risk for preterm birth. Inflammatory pathways are also associated with preterm birth. As such, the current study sought to investigate the potential relationships among preterm birth, acculturation of Hispanic women, and inflammatory markers.

Study Design:

The authors performed an observational study on pregnant Hispanic women in Texas at 22–24 weeks' gestation ( n = 470). The authors obtained demographic data prenatally as well as birth outcome data from the medical chart after delivery. The authors obtained venous blood and used plasma to assay interleukin-1 receptor antagonist (IL-1RA), interleukin-6 (IL-6), and interleukin-10 (IL-10). The authors used logistic regression to understand whether the presence or the absence of IL-10 levels was related to acculturation and the risk of preterm birth.

Results:

The authors observed interactions between undetectable IL-10 levels and years in the United States and undetectable IL-10 levels and being born in the United States in models predicting preterm birth. Follow-up probes of these interactions suggested that when IL-10 was undetectable, preterm birth became more likely as time living in the United States increased, χ2 = 5.15 (1, 416), p = .020, odds ratio (OR) = 3.17, and was more likely in participants born in the United States than in those born elsewhere, χ2 = 5.35 (1, 462), p = .020, OR = 16.78. The authors observed no interactions among acculturation, preterm birth, and IL-1RA and IL-6 levels.

Conclusion:

Acculturated Hispanics who lack the protective effects of IL-10 experience a markedly higher risk of preterm birth than nonacculturated Hispanics.
Prescribing Information Therapy
Authors: Chesser Amy K. , Woods Nicole C. Keene , Davis Aaron A. , Bowers Caleb J.
Published: August 2011

Background: Recently, experts have included information therapy (Ix) as a method for increasing clinician-patient communication, patient adherence, patient understanding of diagnosis and treatment options, and reduction in hospitalizations. Methods: This study, a secondary, retrospective analysis of survey data, independently examined participating patient perceptions of an Ix program between two Mid-western employers. Surveys were administered through the online platform from January 1, 2006 through December 31, 2009 for Employer 1 (N = 4105) and from June 1, 2007 through December 31, 2009 for Employer 2 (N = 8123). Results: Preliminary findings indicate the majority of patients were adherent to recommended treatment(s) and highly rated their physician’s performance. Additionally, patients indicated that their physician’s access to their questionnaire responses motivated them to improve their health literacy and change their health behaviors. Secondary data analysis indicated a positive relationship between prescribed Ix and self-reported health literacy. Conclusion: As Web-based Ix increases in frequency, the evaluation of patient and clinician communication is important and should be expanded to increase the benefits for both patients and clinicians.
Dominant-negative C/ebpα and polycomb group protein Bmi1 extend short-lived hematopoietic stem/progenitor cell life span and induce lethal dyserythropoiesis
Authors: Zhou Ting , Wang Lei , Zhu Kang-Yong , Dong Mei , Xu Peng-Fei , Chen Yi , Chen Sai-Juan , Chen Zhu , Deng Min , Liu Ting Xi
Published: August 2011

The primitive hematopoietic stem/progenitor cells (HSPCs) during embryonic hematopoiesis are thought to be short-lived (SL) with limited self-renewal potential. The fate and consequence of these short-lived HSPCs, once reprogrammed into “long-lived” in a living animal body, remain unknown. Here we show that targeted expression of a dominant-negative C/ebpα (C/ebpαDN) in the primitive SL-HSPCs during zebrafish embryogenesis extends their life span, allowing them to survive to later developmental stage to colonize the definitive hematopoietic sites, where they undergo a proliferative expansion followed by erythropoietic dysplasia and embryonic lethality because of circulation congestion. Mechanistically, C/ebpαDN binds to a conserved C/EBP-binding motif in the promoter region of bmi1 gene, associated with a specific induction of bmi1 transcription in the transgenic embryos expressing C/ebpαDN. Targeted expression of Bmi1 in the SL-HSPCs recapitulates nearly all aberrant phenotypes induced by C/ebpαDN, whereas knockdown of bmi1 largely rescues these abnormalities. The results indicate that Bmi1 acts immediately downstream of C/ebpαDN to regulate the survival and self-renewal of HSPCs and contribute to the erythropoietic dysplasia.
Development of thymic NK cells from double negative 1 thymocyte precursors
Authors: Vargas Claudia L. , Poursine-Laurent Jennifer , Yang Liping , Yokoyama Wayne M.
Published: August 2011

The differentiation of natural killer (NK) cells and a subpopulation of NK cells which requires an intact thymus, that is, thymic NK cells, is poorly understood. Previous in vitro studies indicate that double negative (CD4−CD8−, DN) thymocytes can develop into cells with NK cell markers, but these cells have not been well characterized. Herein, we generated and characterized NK cells differentiating from thymic DN precursors. Sorted DN1 (CD44+CD25−) CD122−NK1.1− thymocytes from Rag1−/− mice were adoptively transferred into Rag1−/−Ly5.1 congenic mice. After intrathymic injection, donor-derived cells phenotypically resembling thymic NK cells were found. To further study their differentiation, we seeded sorted DN1 CD122−NK1.1− thymocytes on irradiated OP9 bone marrow stromal cells with IL-15, IL-7, Flt3L, and stem cell factor. NK1.1+ cells emerged after 7 days. In vitro differentiated NK cells acquired markers associated with immature bone marrow–derived NK cells, but also expressed CD127, which is typically found on thymic NK cells. Furthermore, we found that in vitro cells generated from thymic precursors secreted cytokines when stimulated and degranulated on target exposure. Together, these data indicate that functional thymic NK cells can develop from a DN1 progenitor cell population.
Domain architecture conservation in orthologs
Authors: Forslund Kristoffer , Pekkari Isabella , Sonnhammer Erik LL
Published: August 2011

Background

As orthologous proteins are expected to retain function more often than other homologs, they are often used for functional annotation transfer between species. However, ortholog identification methods do not take into account changes in domain architecture, which are likely to modify a protein's function. By domain architecture we refer to the sequential arrangement of domains along a protein sequence.

To assess the level of domain architecture conservation among orthologs, we carried out a large-scale study of such events between human and 40 other species spanning the entire evolutionary range. We designed a score to measure domain architecture similarity and used it to analyze differences in domain architecture conservation between orthologs and paralogs relative to the conservation of primary sequence. We also statistically characterized the extents of different types of domain swapping events across pairs of orthologs and paralogs.

Results

The analysis shows that orthologs exhibit greater domain architecture conservation than paralogous homologs, even when differences in average sequence divergence are compensated for, for homologs that have diverged beyond a certain threshold. We interpret this as an indication of a stronger selective pressure on orthologs than paralogs to retain the domain architecture required for the proteins to perform a specific function. In general, orthologs as well as the closest paralogous homologs have very similar domain architectures, even at large evolutionary separation.

The most common domain architecture changes observed in both ortholog and paralog pairs involved insertion/deletion of new domains, while domain shuffling and segment duplication/deletion were very infrequent.

Conclusions

On the whole, our results support the hypothesis that function conservation between orthologs demands higher domain architecture conservation than other types of homologs, relative to primary sequence conservation. This supports the notion that orthologs are functionally more similar than other types of homologs at the same evolutionary distance.
Implementation of 3D spatial indexing and compression in a large-scale molecular dynamics simulation database for rapid atomic contact detection
Authors: Toofanny Rudesh D , Simms Andrew M , Beck David AC , Daggett Valerie
Published: August 2011

Background

Molecular dynamics (MD) simulations offer the ability to observe the dynamics and interactions of both whole macromolecules and individual atoms as a function of time. Taken in context with experimental data, atomic interactions from simulation provide insight into the mechanics of protein folding, dynamics, and function. The calculation of atomic interactions or contacts from an MD trajectory is computationally demanding and the work required grows exponentially with the size of the simulation system. We describe the implementation of a spatial indexing algorithm in our multi-terabyte MD simulation database that significantly reduces the run-time required for discovery of contacts. The approach is applied to the Dynameomics project data. Spatial indexing, also known as spatial hashing, is a method that divides the simulation space into regular sized bins and attributes an index to each bin. Since, the calculation of contacts is widely employed in the simulation field, we also use this as the basis for testing compression of data tables. We investigate the effects of compression of the trajectory coordinate tables with different options of data and index compression within MS SQL SERVER 2008.

Results

Our implementation of spatial indexing speeds up the calculation of contacts over a 1 nanosecond (ns) simulation window by between 14% and 90% (i.e., 1.2 and 10.3 times faster). For a 'full' simulation trajectory (51 ns) spatial indexing reduces the calculation run-time between 31 and 81% (between 1.4 and 5.3 times faster). Compression resulted in reduced table sizes but resulted in no significant difference in the total execution time for neighbour discovery. The greatest compression (~36%) was achieved using page level compression on both the data and indexes.

Conclusions

The spatial indexing scheme significantly decreases the time taken to calculate atomic contacts and could be applied to other multidimensional neighbor discovery problems. The speed up enables on-the-fly calculation and visualization of contacts and rapid cross simulation analysis for knowledge discovery. Using page compression for the atomic coordinate tables and indexes saves ~36% of disk space without any significant decrease in calculation time and should be considered for other non-transactional databases in MS SQL SERVER 2008.
Polymorphic variability in the 3' untranslated region (UTR) of IL12B is associated with susceptibility to severe anaemia in Kenyan children with acute Plasmodium falciparum malaria
Authors: Ong'echa John M , Raballah Evans O , Kempaiah Prakasha M , Anyona Samuel B , Were Tom , Davenport Gregory C , Konah Stephen , Vulule John M , Ouma Collins , Hittner James B , Perkins Douglas J
Published: August 2011

Background

Plasmodium falciparummalaria remains a leading cause of morbidity and mortality among African children. Innate immunity provides the first line of defence againstP. falciparuminfections, particularly in young children that lack naturally-acquired malarial immunity, such as the population examined here. Consistent with the fact that elevated interleukin (IL)-12 is an important component of the innate immune response that provides protective immunity against malaria, we have previously shown that suppression of IL-12 in African children is associated with the development of severe malarial anaemia (SMA). Since the role ofIL12Bvariants in conditioning susceptibility to SMA remains largely unexplored, the association between a single nucleotide polymorphism (1188A→C, rs3212227), SMA (Hb<6.0g/dL), circulating IL-12p40/p70 levels, and longitudinal clinical outcomes in Kenyan children (n = 756) residing in a holoendemic falciparum malaria transmission area were investigated.

Results

Multivariate logistic regression analysis in children with acute malaria (n = 544) demonstrated that carriers of the C allele had increased susceptibility to SMA (CC: OR, 1.674; 95% CI, 1.006-2.673;P= 0.047, and AC: OR, 1.410; 95% CI, 0.953-2.087;P= 0.086) relative to wild type (AA). Although children with SMA had lower IL-12p40/p70 levels than the non-SMA group (P= 0.037), levels did not differ significantly according to genotype. Longitudinal analyses in the entire cohort (n = 756) failed to show any significant relationships between rs3212227 genotypes and either susceptibility to SMA or all-cause mortality throughout the three year follow-up.

Conclusion

The rs3212227 is a marker of susceptibility to SMA in children with acute disease, but does not appear to mediate functional changes in IL-12 production or longitudinal outcomes during the acquisition of naturally-acquired malarial immunity.
Comparative effect of olmesartan and candesartan on lipid metabolism and renal function in patients with hypertension: a retrospective observational study
Authors: Nishida Yayoi , Takahashi Yasuo , Nakayama Tomohiro , Soma Masayoshi , Asai Satoshi
Published: August 2011

Background

Angiotensin II receptor blockers (ARBs), including olmesartan and candesartan, are widely used antihypertensive agents. Many clinical studies have demonstrated that ARBs have organ-protecting effects, e.g., cardioprotection, vasculoprotection and renoprotection. However, the effect of prolonged olmesartan monotherapy on lipid metabolism in patients with hypertension is less well studied. We performed a retrospective observational study to compare the effects of olmesartan with those of candesartan, focusing on lipid metabolism and renal function.

Methods

We used data from the Clinical Data Warehouse of Nihon University School of Medicine obtained between Nov 1, 2004 and Feb 28, 2011, to identify cohorts of new olmesartan users (n = 168) and candesartan users (n = 266). We used propensity-score weighting to adjust for differences in all covariates (age, sex, comorbid diseases, previous drugs) between olmesartan and candesartan users, and compared serum chemical data including serum triglyceride (TG), LDL-cholesterol (LDL-C), total cholesterol (TC), potassium, creatinine and urea nitrogen. The mean exposure of olmesartan and candesartan users was 126.1 and 122.8 days, respectively.

Results

After adjustment, there were no statistically significant differences in all covariates between olmesartan and candesartan users. The mean age was 60.7 and 61.0 years, and 33.4% and 33.7% of olmesartan and candesartan users were women, respectively. There were no statistically significant differences in mean values for all laboratory tests between baseline and during the exposure period in both olmesartan and candesartan users. In olmesartan users, the reduction of serum TG level was significant in comparison with that in candesartan users. Other parameters of lipid profile and renal function showed no statistically significant difference in the change from baseline to during the exposure period between olmesartan and candesartan users.

Conclusions

In this study, we observed a more beneficial effect on lipid metabolism, a reduction of serum TG, with olmesartan monotherapy than with candesartan monotherapy. However, there were no clinically significant changes in the levels of all test parameters between baseline and during the exposure period with both drugs. These results suggest that the influence of olmesartan or candesartan monotherapy on lipid metabolism and renal function is small, and that they can be safely used in patients with hypertension.
Sympathetic nervous dysregulation in the absence of systolic left ventricular dysfunction in a rat model of insulin resistance with hyperglycemia
Authors: Thackeray James T , Radziuk Jerry , Harper Mary-Ellen , Suuronen Erik J , Ascah Kathryn J , Beanlands Rob S , DaSilva Jean N
Published: August 2011

Background

Diabetes mellitus is strongly associated with cardiovascular dysfunction, derived in part from impairment of sympathetic nervous system signaling. Glucose, insulin, and non-esterified fatty acids are potent stimulants of sympathetic activity and norepinephrine (NE) release. We hypothesized that sustained hyperglycemia in the high fat diet-fed streptozotocin (STZ) rat model of sustained hyperglycemia with insulin resistance would exhibit progressive sympathetic nervous dysfunction in parallel with deteriorating myocardial systolic and/or diastolic function.

Methods

Cardiac sympathetic nervous integrity was investigated in vivo via biodistribution of the positron emission tomography radiotracer and NE analogue [11C]meta-hydroxyephedrine ([11C]HED). Cardiac systolic and diastolic function was evaluated by echocardiography. Plasma and cardiac NE levels and NE reuptake transporter (NET) expression were evaluated as correlative measurements.

Results

The animal model displays insulin resistance, sustained hyperglycemia, and progressive hypoinsulinemia. After 8 weeks of persistent hyperglycemia, there was a significant 13-25% reduction in [11C]HED retention in myocardium of STZ-treated hyperglycemic but not euglycemic rats as compared to controls. There was a parallel 17% reduction in immunoblot density for NE reuptake transporter, a 1.2 fold and 2.5 fold elevation of cardiac and plasma NE respectively, and no change in sympathetic nerve density. No change in ejection fraction or fractional area change was detected by echocardiography. Reduced heart rate, prolonged mitral valve deceleration time, and elevated transmitral early to atrial flow velocity ratio measured by pulse-wave Doppler in hyperglycemic rats suggest diastolic impairment of the left ventricle.

Conclusions

Taken together, these data suggest that sustained hyperglycemia is associated with elevated myocardial NE content and dysregulation of sympathetic nervous system signaling in the absence of systolic impairment.
What shapes research impact on policy? Understanding research uptake in sexual and reproductive health policy processes in resource poor contexts
Authors: Sumner Andy , Crichton Jo , Theobald Sally , Zulu Eliya , Parkhurst Justin
Published: August 2011

Assessing the impact that research evidence has on policy is complex. It involves consideration of conceptual issues of what determines research impact and policy change. There are also a range of methodological issues relating to the question of attribution and the counter-factual. The dynamics of SRH, HIV and AIDS, like many policy arenas, are partly generic and partly issue- and context-specific. Against this background, this article reviews some of the main conceptualisations of research impact on policy, including generic determinants of research impact identified across a range of settings, as well as the specificities of SRH in particular. We find that there is scope for greater cross-fertilisation of concepts, models and experiences between public health researchers and political scientists working in international development and research impact evaluation. We identify aspects of the policy landscape and drivers of policy change commonly occurring across multiple sectors and studies to create a framework that researchers can use to examine the influences on research uptake in specific settings, in order to guide attempts to ensure uptake of their findings. This framework has the advantage that distinguishes between pre-existing factors influencing uptake and the ways in which researchers can actively influence the policy landscape and promote research uptake through their policy engagement actions and strategies. We apply this framework to examples from the case study papers in this supplement, with specific discussion about the dynamics of SRH policy processes in resource poor contexts. We conclude by highlighting the need for continued multi-sectoral work on understanding and measuring research uptake and for prospective approaches to receive greater attention from policy analysts.
Fixed point results under c-distance in tvs-cone metric spaces
Authors: Đorđević Momčilo , Đorić Dragan , Kadelburg Zoran , Radenović Stojan , Spasić Dragoljub
Published: August 2011

Fixed point and common fixed point results for mappings in tvs-cone metric spaces (with the underlying cone which is not normal) under contractive conditions expressed in the terms of c-distance are obtained. Respective results concerning mappings without periodic points are also deduced. Examples are given to distinguish these results from the known ones.

Mathematics Subject Classification (2010)

47H10, 54H25
ELISA measurement of specific non-antigen-bound antibodies to Aβ1-42 monomer and soluble oligomers in sera from Alzheimer's disease, mild cognitively impaired, and noncognitively impaired subjects
Authors: Klaver Andrea C , Coffey Mary P , Smith Lynnae M , Bennett David A , Finke John M , Dang Loan , Loeffler David A
Published: August 2011

Background

The literature contains conflicting results regarding the status of serum anti-Aβ antibody concentrations in Alzheimer's disease (AD). Reduced levels of these antibodies have been suggested to contribute to the development of this disorder. The conflicting results may be due to polyvalent antibodies, antibody "masking" due to Aβ binding, methodological differences, and/or small sample sizes. The objectives of this pilot study were to compare serum anti-Aβ antibody concentrations between AD, mild cognitive impairment (MCI), and elderly noncognitively impaired (NCI) subjects while addressing these issues, and to perform power analyses to determine appropriate group sizes for future studies employing this approach.

Methods

Serum antibodies to Aβ1-42 monomer and soluble oligomers in AD, MCI, and NCI subjects (10/group) were measured by ELISA, subtracting polyvalent antibody binding and dissociating antibody-antigen complexes. Differences in mean antibody levels were assessed for significance with repeated measures ANOVA using restricted maximum likelihood estimation, using Tukey-Kramer tests and confidence intervals for multiple comparisons. Spearman's rank correlation was used to determine associations between anti-monomer and anti-oligomer antibody concentrations. Estimated sample sizes required to detect effects of various sizes were calculated.

Results

There were no significant differences between groups for mean anti-Aβ antibody levels, although these tended to be higher in AD than NCI specimens. Estimated group sizes of 328 and 150 for anti-Aβ monomer and oligomer antibodies, respectively, would have been required for 80% power for significance at 0.05 for a 25% increase in the AD mean relative to the NCI mean. Serum antibody concentrations to Aβ monomer and oligomers were strongly associated (correlations: 0.798 for undissociated sera, 0.564 for dissociated sera). Antibody-antigen dissociation significantly increased anti-Aβ monomer but not anti-Aβ oligomer antibody levels.

Conclusions

The findings in this pilot study are consistent with relatively similar concentrations of specific, non-antigen-bound antibodies to Aβ1-42 monomer and soluble oligomers in AD, MCI, and NCI sera. The differences between groups for these antibodies would have required approximate group sizes of 328 and 150, respectively, for a high probability for statistical significance. These findings do not support the hypothesis that reduced levels of anti-Aβ antibodies might contribute to AD's pathogenesis.
Cellular phenotype impacts human immunodeficiency virus type 1 viral protein R subcellular localization
Authors: Ferrucci Adriano , Nonnemacher Michael R , Wigdahl Brian
Published: August 2011

Background

Human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) is a virion-associated regulatory protein that functions at several points within the viral life cycle and has been shown to accumulate primarily in the nucleus and at the nuclear envelope. However, most studies have investigated Vpr localization employing cell types irrelevant to HIV-1 pathogenesis. To gain a better understanding of how cellular phenotype might impact HIV-1 Vpr intracellular localization, Vpr localization was examined in several cell lines representing major cellular targets for HIV-1 infection within the peripheral blood, bone marrow, and central nervous system (CNS).

Results

Utilizing a green fluorescent protein-tagged Vpr, we detected Vpr mainly in foci inside the nucleus, at the nuclear envelope, and around the nucleoli, with dispersed accumulation in the cytoplasm of human endothelial kidney 293T cells. No differences were observed in Vpr localization pattern with respect to either the location of the tag (N- or C-terminus) or the presence of other viral proteins. Subsequently, the Vpr localization pattern was explored in two primary HIV-1 target cells within the peripheral blood: the CD4+ T lymphocyte (represented by the Jurkat CD4+ T-cell line) and the monocyte-macrophage (represented by the U-937 cell line). Vpr was found primarily in speckles within the cytoplasm of the Jurkat T cells, whereas it accumulated predominantly intranuclearly in U-937 monocytic cells. These patterns differ from that observed in a bone marrow progenitor cell line (TF-1), wherein Vpr localized mainly at the nuclear envelope with some intranuclear punctuate staining. Within the CNS, we examined two astroglioma cell lines and found that Vpr displayed a perinuclear and cytoplasmic distribution.

Conclusions

The results suggest that the pattern of Vpr localization depends on cellular phenotype, probably owing to interactions between Vpr and cell type-specific host factors. These interactions, in turn, are likely coupled to specific roles that Vpr plays in each cell type within the context of the viral life cycle. Phenotype-specific Vpr localization patterns might also provide an explanation with respect to Vpr secretion or release from HIV-1-infected cells within the peripheral blood and CNS.
Admission risk factors for cerebral vasospasm in ruptured brain arteriovenous malformations: An observational study
Authors: Chhor Vibol , Le Manach Yannick , Clarençon Fréderic , Nouet Aurélien , Daban Jean-Louis , Abdennour Lamine , Puybasset Louis , Lescot Thomas
Published: August 2011

Introduction

Cerebral vasospasm is a well-documented complication of aneurismal subarachnoid hemorrhage but has not been extensively studied in brain arteriovenous malformations (BAVMs). Here, our purpose was to identify risk factors for cerebral vasospasm after BAVM rupture in patients requiring intensive care unit (ICU) admission.

Methods

Patients admitted to our ICU from January 2003 to May 2010 for BAVM rupture were included in this observational study. Clinical, laboratory and radiological features from admission to ICU discharge were recorded. The primary endpoint was cerebral vasospasm by transcranial Doppler (TCD-VS) or cerebral infarction (CI) associated with vasospasm. Secondary endpoints included the Glasgow Outcome Scale (GOS) at ICU discharge.

Results

Of 2,734 patients admitted to our ICU during the study period, 72 (2.6%) with ruptured BAVM were included. TCD-VS occurred in 12 (17%) and CI in 6 (8%) patients. All patients with CI had a previous diagnosis of TCD-VS. A Glasgow Coma Scale score <8 was a risk factor for both TCD-VS (relative risk (RR), 4.7; 95% confidence interval (95% CI), 1.6 to 26) and CI (RR, 7.8; 95% CI, 0.1 to 63). Independent risk factors for TCD-VS by multivariate analysis were lower Glasgow Coma Scale score (odds ratio (OR) per unit decrease, 1.38; 95% CI, 1.13 to 1.80), female gender (OR, 4.86; 95% CI, 1.09 to 25.85), and younger age (OR per decade decrease, 1.39; 95% CI, 1.05 to 1.82). The risk of a poor outcome (GOS <4) at ICU discharge was non-significantly increased in the patients with TCD-VS (RR, 4.9; 95% CI, 0.7 to 35; P = 0.09). All six patients with CI had poor outcomes.

Conclusions

This is the first cohort study describing the incidence and risk factors for cerebral vasospasm after BAVM rupture. Larger studies are needed to investigate the significance of TCD-vasospasm and CI in these patients.
Source-receiver interferometry for seismic wavefield construction and ground-roll removal
Authors: Duguid Craig , Halliday David , Curtis Andrew
Published: August 2011

Seismic interferometry describes the construction of unmeasured wavefield responses (or Green's functions) between two or more points by applying cross-correlation, deconvolution, or convolution to seismic data recordings. The practical implications are that, applying inter-receiver interferometry, a “virtual” (imaginary) source of energy can be created at the location to a real receiver by using energy recorded from surrounding sources. Similarly, by using inter-source interferometry, a virtual receiver can be created at the location of a real source by using energy recorded at surrounding receivers (Curtis et al., 2009). These two methods can be combined to create the new technique of source-receiver interferometry (Curtis, 2009; Curtis and Halliday, 2010; Halliday and Curtis, 2010) which synthesizes real-source to real-receiver Green's function estimates using only energy recorded at a surrounding boundary of receivers and from an additional surrounding boundary of sources. The boundary sources in each case can be active (such as an explosive or vibrating source) or passive (such as noise from anthropogenic activity or ocean waves). This paper describes the first real-data application of source-receiver interferometry, and demonstrates its potential to enhance existing methods of interferometric ground-roll suppression.
Delineation of concealed basement depression from aeromagnetic studies of Mahanadi Basin, East Coast of India
Authors: Sarma B.S.P. , Chakravarthi V.
Published: August 2011

A detailed study of aeromagnetic anomalies across the Mahanadi Basin on the east coast of India has brought out a concealed basement depression, trending ENE-WSW, in the Rajnagar-Paradeep region. In this article, the aeromagnetic data pertaining to the Rajnagar-Paradeep region are analyzed quantitatively for their basement structure. The inferred basement depression, bounded on the north by a low-angle normal fault and in the south by a steep fault, characterizes the features of a typical half-graben structure. Furthermore, the southern boundary fault of the inferred depression correlates with an ENE-WSW-striking northward-dipping fault in the offshore region. The fact that the marine gravity anomaly also shows discrete lows over this region substantiates the aeromagnetic interpretation.
Applications of interbed multiple attenuation
Authors: Griffiths Malcolm , Hembd Jeshurun , Prigent Hervé
Published: August 2011

Surface-related multiple attenuation schemes have proven useful in attenuating a significant proportion of the high-amplitude multiple content in seismic data. Although generally sufficient for exploration purposes, there is growing recognition that more complicated interbed multiples exist within the data and that they may interfere with the interpretation of reservoirs and other areas of interest. In this paper, we examine a data-driven method and a model-driven method for attenuating internal multiples showing both synthetic and real-world examples of their application.
Case studies in 3D interbed multiple attenuation
Authors: Brookes David
Published: August 2011

Attenuating water-column multiples with 3D SRME has become common practice, but interbed multiples are not attenuated with this technique since these multiples do not reflect from the free surface. Interbed multiples are often reflected between closely spaced events, giving them an effective velocity very similar to primary events. Because there is little moveout discrimination, interbed multiples do not respond to Radon multiple attenuation or other moveout-based techniques. Extending the concept of SRME to predict interbed multiples is not a new idea, but the 3D implementation was not widely applied until recently. The increase in available computing power has made 3D IME (interbed multiple elimination) a viable option. This paper will discuss a synthetic data set, a Gulf of Mexico marine data set, and an Egyptian Western Desert land data set. Attenuating interbed multiples is an important issue in exploration, especially in the Middle East, where this type of multiple is particularly problematic because the anti-multiple tools based on velocity differences do not work well in this geologic setting. In the salt provinces, attenuating interbed multiples is of particular importance as their presence greatly inhibits interpretation. In addition, removing this class of multiple is very helpful in understanding dirty salt.
Regional Economic Impacts of a Verdugo Scenario Earthquake Disruption of Los Angeles Water Supplies: A Computable General Equilibrium Analysis
Authors: Rose Adam , Liao Shu-Yi , Bonneau Amanda
Published: August 2011

This paper advances the state of the art in the development and application of a computable general equilibrium model to estimate the business interruption impacts of a Verdugo scenario earthquake on the water system serving Los Angeles. The model has been especially designed to incorporate engineering and spatial aspects of this system in the context of the regional economy to include resilience responses at various water outage levels. The Verdugo earthquake scenario and Monte Carlo simulations show that water outages in LA County could result in business interruption losses of several billion dollars without any resilience adjustment. However, a reduction of these losses by more than 90% is possible through the application of several types of resilience on the customer side, most prominently rescheduling production, in addition to conservation, input substitution, and storage of water. Allowing the price of water to rise to reflect its scarcity would reduce the losses even further.
Endoscopic Image-Guided Transcervical Odontoidectomy
Authors: Dasenbrock Hormuzdiyar H. , Clarke Michelle J. , Bydon Ali , Sciubba Daniel M. , Witham Timothy F. , Gokaslan Ziya L. , Wolinsky Jean-Paul
Published: August 2011

BACKGROUND:

Ventral decompression with posterior stabilization is the preferred treatment for symptomatic irreducible basilar invagination. Endoscopic image-guided transcervical odontoidectomy (ETO) may allow for decompression with limited morbidity.

OBJECTIVE:

To describe the perioperative outcomes of patients undergoing anterior decompression of basilar invagination with the use of ETO.

METHODS:

Fifteen patients who had a follow-up of at least 16 months were retrospectively reviewed. Intraoperatively, the vertebral body of C2 was removed and the odontoid was resected in a “top-down” manner using endoscopic visualization and frameless stereotactic navigation. Posterior instrumented stabilization was subsequently performed.

RESULTS:

The average (± standard deviation) age of the patients was 42.6 ± 24.5 (range, 11–72) years. Postoperative complications occurred in 6 patients, including a urinary tract infection (n = 2), upper airway swelling (n = 2), dysphagia (n = 2), gastrostomy tube placement (n = 1), and an asymptomatic pseudomeningocele (n = 1). No patients required a tracheostomy, had bacterial meningitis, or developed a venous thromboembolic event; only 1 patient was intubated for more than 48 hours postoperatively. With a mean follow-up of 41.9 ± 14.4 (range, 16–59) months, myelopathy improved in all patients and no patient experienced late neurological deterioration. The mean modified Japanese Orthopedic Association (JOA) score increased from 11.2 ± 4.2 to 15.9 ± 1.4 (P = .002). Patients with a diagnosis other than rheumatoid arthritis or who had a higher preoperative JOA score had a significantly better postoperative neurological recovery (P = .005).

CONCLUSION:

ETO may be a valid treatment for patients with symptomatic irreducible basilar invagination that avoids some of the morbidity of transoral surgery and leads to long-term improvement in myelopathy.
Hearing Preservation Using the Middle Fossa Approach for the Treatment of Vestibular Schwannoma
Authors: Kutz Joe Walter , Scoresby Tyler , Isaacson Brandon , Mickey Bruce E. , Madden Christopher J. , Barnett Samuel L. , Coimbra Caetano , Hynan Linda S. , Roland Peter S.
Published: August 2011

BACKGROUND:

The incidence of small vestibular schwannomas in patients with serviceable hearing is increasing because of the widespread use of MRI. The middle fossa approach provides the patient with an opportunity for tumor removal with hearing preservation.

OBJECTIVE:

To determine the rate of hearing preservation and facial nerve outcomes after removal of a vestibular schwannoma with the use of the middle fossa approach.

METHODS:

A retrospective case review at a tertiary, academic medical center was performed identifying patients from 1998 through 2008 that underwent removal of a vestibular schwannoma by the middle fossa approach. Preoperative and postoperative audiograms were compared to determine hearing preservation rates. In addition, facial nerve outcomes at last follow-up were recorded.

RESULTS:

Forty-six patients underwent a middle fossa craniotomy for the removal of a vestibular schwannoma. Of the 38 patients that had class A or class B hearing preoperatively, 24 (63.2%) retained class A or B hearing and 29 (76.3%) retained class A, B, or C hearing. When tumors were 10 mm or less in patients with class A or B preoperative hearing, 22 of 30 patients (73.3%) retained class A or B hearing. When the tumor size was greater than 10 mm in patients with class A or B preoperative hearing, 2 of 8 patients (25%) retained class A or B hearing. At most recent follow-up, 76.1% of patients had House-Brackmann grade I facial function, 13.0% had House-Brackmann grade II facial function, and 10.9% had House-Brackmann grade III facial function.

CONCLUSION:

Hearing preservation rates are excellent using the middle fossa approach, especially for smaller tumors. No patient experienced long-term facial nerve function worse than House-Brackmann grade III.
Wing motion measurement and aerodynamics of hovering true hoverflies
Authors: Mou Xiao Lei , Liu Yan Peng , Sun Mao
Published: August 2011

Most hovering insects flap their wings in a horizontal plane (body having a large angle from the horizontal), called `normal hovering'. But some of the best hoverers, e.g. true hoverflies, hover with an inclined stroke plane (body being approximately horizontal). In the present paper, wing and body kinematics of four freely hovering true hoverflies were measured using three-dimensional high-speed video. The measured wing kinematics was used in a Navier–Stokes solver to compute the aerodynamic forces of the insects. The stroke amplitude of the hoverflies was relatively small, ranging from 65 to 85 deg, compared with that of normal hovering. The angle of attack in the downstroke (∼50 deg) was much larger that in the upstroke (∼20 deg), unlike normal-hovering insects, whose downstroke and upstroke angles of attack are not very different. The major part of the weight-supporting force (approximately 86%) was produced in the downstroke and it was contributed by both the lift and the drag of the wing, unlike the normal-hovering case in which the weight-supporting force is approximately equally contributed by the two half-strokes and the lift principle is mainly used to produce the force. The mass-specific power was 38.59–46.3 and 27.5–35.4 W kg–1 in the cases of 0 and 100% elastic energy storage, respectively. Comparisons with previously published results of a normal-hovering true hoverfly and with results obtained by artificially making the insects' stroke planes horizontal show that for the true hoverflies, the power requirement for inclined stroke-plane hover is only a little (<10%) larger than that of normal hovering.