bluuebunny/crossref_metadata_2025 huggingface dataset:
MEASURING THE MULTI-DIMENSIONAL KNOWLEDGE DEPRIVATION OF HIV/AIDS: A NEW APPROACH WITH INDIAN EVIDENCE ON ITS MAGNITUDE AND DETERMINANTS
Authors: RAY RANJAN , SINHA KOMPAL
Published: July 2011

Though HIV/AIDS poses serious risks to economic security, there is very little economics literature quantifying awareness and knowledge of this disease and their principal socioeconomic determinants. This is what the present study attempts to do in the context of India, which faces a significant threat from HIV/AIDS. The study is based on India's National Family Health Surveys covering the period of economic reforms and beyond. The contribution is both methodological and empirical. The study shows that the recent multi-dimensional deprivation approach to poverty can also be used to measure and analyse awareness and lack of knowledge of HIV/AIDS. The use of decomposable multi-dimensional measures helps in identifying regions, socioeconomic groups and aspects of HIV knowledge that should be targeted in policy interventions. The study identifies the importance of safe sex practices as an area that needs to be targeted in future information campaigns. The study also explores the impact of increased female autonomy in health and economic decision-making on their and their partners' knowledge of the disease, along with a host of other economic and demographic determinants.
BIOLOGICAL FITNESS AND ACTION OPPORTUNITY OF NATURAL SELECTION IN AN URBAN POPULATION OF CUBA: PLAZA DE LA REVOLUCIÓN, HAVANA
Authors: VAZQUEZ VANESSA , ALONSO VERÓNICA , LUNA FRANCISCO
Published: July 2011

This paper describes the biological fitness of an urban population of Havana city, Plaza de la Revolución, which has the lowest fertility and the highest demographic ageing in Cuba. The aim is to assess the biological fitness of this community through the indexes of action opportunity of natural selection, to determine its evolutionary pattern and the influence of its socio-cultural peculiarity. Demographic data were obtained from the reproductive histories of 1200 women between the ages of 55 and 64. Data concerning mortality and surviving offspring from the first embryonic stages until age of reproduction were also collected. In order to measure the level of biological fitness two indexes were used: the Crow index of action opportunity of natural selection and the corrected index proposed by Johnston and Kensinger, which takes into account prenatal mortality. This corrected index was calculated including and excluding induced abortions in order to evaluate the contribution of these to biological fitness. When only postnatal mortality was considered, the results showed an evolutionary pattern similar to that of developed countries, based on low mortality and fertility. However, when prenatal mortality was taken into account, biological fitness decreased and the corrected index of natural selection was 4.5 times higher than when miscarriages and fetal deaths were not considered. Moreover, this corrected index was 2.65 times higher when induced miscarriages were considered, indicating the large decrease in biological fitness as a result of the current reproductive behaviour of frequent induced abortion.
Frontal osteomas: standardising therapeutic indications
Authors: Gil-Carcedo L M , Gil-Carcedo E S , Vallejo L A , de Campos J M , Herrero D
Published: July 2011

Background:

We believe the currently accepted indications for frontal osteoma surgery are inappropriate. We propose a new osteoma classification system, below, in order to standardise surgical decisions.

Method:

Osteomas were classified based on: relationship of tumour mass to sinus size; tumour proximity to the infundibulum, destruction of sinus walls, and complications. Forty-five osteoma cases were thus classified (1971–2007), 29 of which underwent surgery (64.44 per cent).

Results:

Three stages were thus derived: I, tumour/air fraction less than one-third, tumour distant from the infundibulum, no sinusitis, and no complications (18 patients (40 per cent)); II, tumour/air fraction one-third to one-half, no infundibular obstruction, no bone destruction, no sinusitis, and no complications (six (13.33 per cent)); and III, tumour/air fraction more than one-half, partial or total infundibular obstruction, sinusitis, bone destruction, and/or complications (21 (46.67 per cent)).

Conclusion:

Study findings suggest the following surgical indications: stage I, no surgery required, implement monitoring protocol; stage II, implement monitoring protocol, surgery may be required depending on tumour severity and general patient condition; and stage III, surgery always required. This system provides a method of standardising osteoma surgical decisions.
Encystment site affects the reproductive strategy of a progenetic trematode in its fish intermediate host: is host spawning an exit for parasite eggs?
Authors: HERRMANN KRISTIN K. , POULIN ROBERT
Published: July 2011

Each transmission event in complex, multi-host life cycles create obstacles selecting for adaptations by trematodes. One such adaptation is life cycle abbreviation through progenesis, in which the trematode precociously matures and reproduces within the second intermediate host. Progenesis eliminates the need for the definitive host and increases the chance of life cycle completion. However, progenetic individuals face egg-dispersal challenges associated with reproducing within metacercarial cysts in the tissues or body cavity of the second intermediate host. Most progenetic species await host death for their eggs to be released into the environment. The present study investigated temporal variation of progenesis inStegodexamene anguillaein one of its second intermediate fish hosts and the effect of the fish's reproductive cycle on progenesis. The study involved monthly sampling over 13 months at one locality. A greater proportion of individuals became progenetic in the gonads of female fish hosts. Additionally, progenesis of worms in the gonads was correlated with seasonal daylight and temperature changes, major factors controlling fish reproduction. Host spawning events are likely to be an avenue of egg dispersal for this progenetic species, with the adoption of progenesis being conditional on whether or not the parasite can benefit from fish spawning.
Curupira-1 and Curupira-2, two novel Mutator-like DNA transposons from the genomes of human parasitesSchistosoma mansoniandSchistosoma japonicum
Authors: JACINTO DANIELE S. , MUNIZ HELOISA DOS SANTOS , VENANCIO THIAGO M. , WILSON R. ALAN , VERJOVSKI-ALMEIDA SERGIO , DEMARCO RICARDO
Published: July 2011

Transposons of the Mutator superfamily have been widely described in plants, but only recently have metazoan organisms been shown to harbour them. In this work we describe novel Mutator superfamily transposons from the genomes of the human parasitesSchistosoma mansoniandS. japonicum, which we name Curupira-1 and Curupira-2. Curupira elements do not have Terminal Inverted Repeats (TIRs) at their extremities and generate Target Site Duplications (TSDs) of 9 base pairs. Curupira-2 transposons code for a conserved transposase and SWIM zinc finger domains, while Curupira-1 elements comprise these same domains plus a WRKY zinc finger. Alignment of transcript sequences from both elements back to the genomes indicates that they are subject to splicing to produce mature transcripts. Phylogenetic analyses indicate that these transposons represent a new lineage of metazoan Mutator-like elements with characteristics that are distinct from the recently described Phantom elements. Description of these novel schistosome transposons provides new insights in the evolution of transposable elements in schistosomes.
Ichthyobodo salmonis sp. n. (Ichthyobodonidae, Kinetoplastida), an euryhaline ectoparasite infecting Atlantic salmon (Salmo salar L.)
Authors: ISAKSEN TROND E. , KARLSBAKK EGIL , WATANABE KUNINORI , NYLUND ARE
Published: July 2011

Phylogenetic analyses of SSU rDNA sequences have previously revealed the existence of 2 Ichthyobodo species able to infect Atlantic salmon (Salmo salar L.). Ichthyobodo necator sensu stricto (s.s.) is assumed to be a freshwater parasite, while a genetically distinct but undescribed species, Ichthyobodo sp. II sensu Todal et al. (2004) have been detected on Atlantic salmon in both fresh- and seawater. In the present study a morphological description of Ichthyobodo sp. II from the gills of salmon reared in fresh-, brackish- and seawater is presented, using both light- and electron microscopy. Comparative morphometry show that Ichthyobodo sp. II from both freshwater and seawater displays a different cell shape, and is significantly smaller than I. necator s.s. Also, ultrastructural characteristics distinguish these two species, notably differences in the attachment region and the presence of spine-like surface projections in Ichthyobodo sp. II. Based on both unique SSU rDNA sequences and morphological characteristics, we conclude that Ichthyobodo sp. II. represents a novel species for which we propose the name Ichthyobodo salmonis sp. n.
Do different parasite species interact in their effects on host fitness? A case study on parasites of the amphipodParacalliope fluviatilis
Authors: RAUQUE C. A. , PATERSON R. A. , POULIN R. , TOMPKINS D. M.
Published: July 2011

There is a gap in our understanding of the relative and interactive effects of different parasite species on the same host population. Here we examine the effects of the acanthocephalanAcanthocephalus galaxii, an unidentified cyclophyllidean cestode, and the trematodesCoitocaecum parvumandMicrophallussp. on several fitness components of the amphipodParacalliope fluviatilis, using a combination of infection surveys and both survival and behavioural trials. In addition to significant relationships between specific parasites and measures of amphipod survival, maturity, mating success and behaviour, interactions between parasite species with respect to amphipod photophilia were also significant. While infection by eitherA. galaxiiorC. parvumwas associated with increased photophilia, such increases were negated by co-infection withMicrophallussp. We hypothesize that this is due to the more subtle manipulative effect ofA. galaxiiandC. parvumbeing impaired byMicrophallussp. We conclude that the low frequency at which such double infections occur in our sampled population means that such interactions are unlikely to be important beyond the scale of the host individual. Whether or not this is generally true, implying that parasitological models and theory based on single parasite species studies do generally hold, requires cross-species meta-analytical studies.
A cluster analysis-derived classification of psychological distress and illness behavior in the medically ill
Authors: Fava G. A. , Guidi J. , Porcelli P. , Rafanelli C. , Bellomo A. , Grandi S. , Grassi L. , Mangelli L. , Pasquini P. , Picardi A. , Quartesan R. , Rigatelli M. , Sonino N.
Published: July 2011

Background

The classification of psychological distress and illness behavior in the setting of medical disease is still controversial. Current psychiatric nosology does not seem to cover the spectrum of disturbances. The aim of this investigation was to assess whether the joint use of DSM-IV categories and the Diagnostic Criteria for Psychosomatic Research (DCPR), that provide identification of syndromes related to somatization, abnormal illness behavior, irritable mood, type A behavior, demoralization and alexithymia, could yield subtyping of psychosocial variables in the medically ill.

Method

A cross-sectional assessment using both DSM-IV and the DCPR was conducted in eight medical centers in the Italian Health System. Data were submitted to cluster analysis. Participants were consecutive medical out-patients and in-patients for whom a psychiatric consultation was requested. A total of 1700 subjects met eligibility criteria and 1560 agreed to participate.

Results

Three clusters were identified: non-specific psychological distress, irritability and affective disturbances with somatization.

Conclusions

Two-step cluster analysis revealed clusters that were found to occur across clinical settings. The findings indicate the need of expanding clinical assessment in the medically ill to include the various manifestations of somatization, illness behavior and subclinical distress encompassed by the DCPR.
Multiple-weighted norm inequalities for maximal multi-linear singular integrals with non-smooth kernels
Authors: Grafakos Loukas , Liu Liguang , Yang Dachun
Published: July 2011

We obtain weighted norm inequalities for maximal truncated operators of multi-linear singular integrals with non-smooth kernels in the sense of Duong et al. This class of operators extends the class of multi-linear Calderón-Zygmund operators introduced by Coifman and Meyer and includes the higher-order commutators of Calderón. The weighted norm inequalities obtained in this work are with respect to the new class of multiple weights of Lerner et al. The key ingredient in the proof is the introduction of a new multi-sublinear maximal operator that plays the role of the Hardy-Littlewood maximal function in a version of Cotlar's inequality. As applications of these results, new weighted estimates for the mth order Calderón commutators and their maximal counterparts are deduced.
Boundary blow-up solutions for elliptic equations with gradient terms and singular weights: existence, asymptotic behaviour and uniqueness
Authors: Chen Yujuan , Wang Mingxin
Published: July 2011

This paper deals with the non-negative boundary blow-up solutions of the equation ∆u = b(x)up + c(x)uσ|∇u|q in Ω ⊂ ℝ,N, where b(x), c(x) ∈ Cγ (Ω,ℝ+) for some 0 < γ < 1 and can be vanishing or singular on the boundary, and p, σ and q are non-negative constants. The existence and asymptotic behaviour of such a solution near the boundary are investigated, and we show how the nonlinear gradient term affects the results. As a consequence of the asymptotic behaviour, we also show the uniqueness result.
Asymptotic expansion of solutions to an inverse problem of parabolic type with non-homogeneous boundary conditions
Authors: Guidetti Davide
Published: July 2011

We consider an inverse parabolic problem of reconstruction of the source function, together with the traditional solution. In contrast with older literature, we consider non-homogeneous and time-dependent boundary conditions. We are able to prove a general result of convergence to a stationary state, and of asymptotic expansion as t → ∞.
Aging in Rural Canada: A Retrospective and Review
Authors: Keating Norah , Swindle Jennifer , Fletcher Stephanie
Published: July 2011

La recherche sur le vieillissement en milieu rural s’est développée considérablement depuis la publication du livre,Aging in Rural Canada(Butterworths, 1991). Le but de cet article est double : de fournir une rétrospective sur les questions de viellissement en milieu rural tirée de ce livre, et une revue de la littérature canadienne sur le vieillissement en milieu rural depuis sa publication. L’examen met en évidence les nouvelles orientations dans les définitions conceptuelles du « rural », et dans les questions de l’engagement social, l’indépendance, les réseaux familiaux et sociaux et les services ruraux et la santé. Deux perspectives principales de recherche sont évidents. Le point de vue ou l’optique d’analyse de la marginalisation se concentre sur les personnes âgées en milieu rural ayant des problèmes de santé, mais n’a pas inclus celles qui sont marginalisées par la pauvrété ou le sexe. L’optique d’analyse du vieillissement sain se concentre sur les contributions et l’engagement, mais a omis la recherche sur les relations sociales et la qualité de l’interaction familiale. Le rapport comprend un appel s’interroger sur l’interaction entre les gens et leur lieu de vie et à comprendre les enjeux de la diversité en milieu rural et le processus de vieillissement en milieu rural.
The combined effects of prenatal drug exposure and early adversity on neurobehavioral disinhibition in childhood and adolescence
Authors: Fisher Philip A. , Lester Barry M. , DeGarmo David S. , Lagasse Linda L. , Lin Hai , Shankaran Seetha , Bada Henrietta S. , Bauer Charles R. , Hammond Jane , Whitaker Toni , Higgins Rosemary
Published: July 2011

The negative effects of prenatal substance exposure on neurobiological and psychological development and of early adversity are clear, but little is known about their combined effects. In this study, multilevel analyses of the effects of prenatal substance exposure and early adversity on the emergence of neurobehavioral disinhibition in adolescence were conducted. Neurobehavioral disinhibition has previously been observed to occur frequently in multiproblem youth from high-risk backgrounds. In the present study, neurobehavioral disinhibition was assessed via behavioral dysregulation and poor executive function composite measures. Data were drawn from a prospective longitudinal investigation of prenatal substance exposure that included 1,073 participants followed from birth through adolescence. The results from latent growth modeling analyses showed mean stability but significant individual differences in behavioral dysregulation and mean decline with individual differences in executive function difficulties. Prior behavioral dysregulation predicted increased executive function difficulties. Prenatal drug use predicted the emergence and growth in neurobehavioral disinhibition across adolescence (directly for behavioral dysregulation and indirectly for executive function difficulties via early adversity and behavioral dysregulation). Prenatal drug use and early adversity exhibited unique effects on growth in behavioral dysregulation; early adversity uniquely predicted executive function difficulties. These results are discussed in terms of implications for theory development, social policy, and prevention science.
Growth delay as an index of allostatic load in young children: Predictions to disinhibited social approach and diurnal cortisol activity
Authors: Johnson Anna E. , Bruce Jacqueline , Tarullo Amanda R. , Gunnar Megan R.
Published: July 2011

The goal of this study was to examine whether growth delay can serve as an index of allostatic load during early development, as it is well known that the activity of stress-mediating systems inhibits growth. The participants were children adopted internationally from institutional care (n= 36), children adopted internationally from foster care (n= 26), and nonadopted children (n= 35). For the adopted children, height for age and weight for height were assessed at adoption; for all children, disinhibited social approach (DSA; termed elsewhere as “indiscriminate friendliness”) and diurnal cortisol were assessed at 6–8 years (M= 6.9 years). For internationally adopted children in general, and postinstitutionalized children specifically, linear growth delay assessed at the time of adoption was associated with more dysregulated behavior in response to an unfamiliar adult (i.e., greater DSA) and a more dysregulated diurnal cortisol rhythm (i.e., higher late afternoon and evening values). Further, among the most growth-delayed children, higher cortisol levels later in the day were correlated with DSA. The potential for using growth delay as an allostatic load indicator and the possible problems and limitations in its use in child populations are discussed.
What can allostasis tell us about anabolic–androgenic steroid addiction?
Authors: Hildebrandt Tom , Yehuda Rachel , Alfano Lauren
Published: July 2011

Anabolic–androgenic steroids (AASs) are synthetic hormones used by individuals who want to look better or perform better in athletics and at the gym. Their use raises an interesting paradox in which drug use is associated with a number of health benefits, but also the possibility of negative health consequences. Existing models of AAS addiction follow the traditional framework of drug abuse and dependence, which suggest that harmful use occurs as a result of the drug's ability to hijack the motivation–reward system. However, AASs, unlike typical drugs of abuse, are not used for acute intoxication effects or euphoria. Rather, AASs are used to affect the body through changes to the musculoskeletal system and the hypothalamic–pituitary–gonadal axis as opposed to stimulating the reward system. We offer an allostatic model of AAS addiction to resolve this inconsistency between traditional drug addiction and AAS addiction. This allostatic framework provides a way to (a) incorporate exercise into AAS misuse, (b) identify where AAS use transitions from recreational use into a drug problem, and (c) describe individual differences in vulnerability or resilience to AASs. Implications for this model of AAS addiction are discussed.
Allostatic processes in the family
Authors: Repetti Rena L. , Robles Theodore F. , Reynolds Bridget
Published: July 2011

The concepts of allostatic load and allostatic processes can help psychologists understand how health trajectories are influenced by stressful childhood experiences in the family. This paper describes psychological pathways and two key allostatic mediators, the hypothalamic–pituitary–adrenal axis and the immune system, through which stressful early rearing conditions may influence adult mental and physical health. The action of meshed gears is introduced as a metaphor to illustrate how responses occurring within a brief time frame, for example, immediate reactions to stressors, can influence developmental and health processes unfolding over much longer spans of time. We identify early-developing psychological and biological response patterns that could link chronic stressors in childhood to later health outcomes. Some of these “precursor outcomes” (e.g., heightened vigilance and preparedness for threats; enhanced inflammatory and humoral responses to infectious microorganisms) appear to be aimed at protection from immediate dangers; they may reflect “adaptive trade-offs” that balance short-term survival advantages under harsh rearing conditions against disadvantages manifested later in development. Our analysis also suggests mechanisms that underlie resilience in risky family environments.
Early adversity and adult health outcomes
Authors: Taylor Shelley E. , Way Baldwin M. , Seeman Teresa E.
Published: July 2011

Adversity in childhood has effects on mental and physical health, not only in childhood but across the lifespan. A chief task of our research has been to define the pathways by which childhood experience has these surprising health outcomes, often decades later. The concept of allostatic load, which refers to dysregulations across major biological regulatory systems that have cumulative interacting adverse effects over time, provides a mechanism for understanding these relations and defining specific pathways. To chart these pathways, we examine early childhood socioeconomic status, family environment, and genetic predispositions as antecedents to socioemotional functioning/psychological distress; and neural responses to threat that have downstream effects on major stress regulatory systems, ultimately culminating in risks to mental and physical health outcomes. This integrative approach to investigating the impact of childhood experience on adult health outcomes illustrates the significance of multilevel integrative approaches to understanding developmental psychopathology more generally.
A NOTE ON SOCIAL SECURITY WELFARE WITH SELF-CONTROL PROBLEMS
Authors: Bucciol Alessandro
Published: July 2011

We develop an overlapping-generations model for a closed economy with uncertainty on labor income and mortality risk to show that unfunded social security programs may increase welfare in economies where agents are affected by self-control problems à la Gul and Pesendorfer (2001, Econometrica 69, 1403). We depart from the existing literature by setting the agent's preference parameters to match target levels of macro-variables observed in the real U.S. economy. In our approach, economies with tempted and nontempted agents are indistinguishable in terms of aggregate consumption, labor, and saving behavior when social security provides a replacement rate of 40% (as in the United States). This situation makes agents bear costly self-control problems over more years. Our simulations indicate that social security improves welfare with degrees of temptation equal to 11% or higher. A social security program with a replacement rate of 40% finds support for degrees of temptation not lower than 15%.
Impact of using nationalv. international definitions of underweight, overweight and obesity: an example from Kuwait
Authors: El-Ghaziri Mira , Boodai Shurooq , Young David , Reilly John J
Published: July 2011

Objective

To compare the classification of overweight, obesity and underweight using internationalv. national approaches in Kuwaiti adolescents.

Design

Assessment of underweight, overweight and obesity using a national approach (based on Kuwaiti reference data for BMI-for-age) was compared with assessments obtained using three international approaches: the Coleet al.and International Obesity Task Force (IOTF) definitions of thinness and of overweight and obesity (Cole-IOTF); WHO 2007; and US Centers for Disease Control and Prevention (CDC) 2000 reference data and definitions. The degree of agreement between the different methods was assessed using the weightedκstatistic (κw).

Setting

Two randomly selected public intermediate schools in Kuwait City.

Subjects

A total of 499 10–14-year-old Kuwaiti adolescents.

Results

Prevalence of overweight and obesity using Kuwaiti reference data (36·7 %; 95 % CI 32·4, 41·1) was significantly lower than that obtained using international approaches – Cole-IOTF (44·7 %; 95 % CI 40·3, 49·2), CDC 2000 (44·9 %; 95 % CI 40·5, 49·4) and WHO 2007 (50·5 %; 95 % CI 46·0, 55·0) (P< 0·01). All three international approaches showed almost perfect agreement: IOTFv. WHO (κw= 0·82; 95 % CI 0·79, 0·85) and IOTFv. CDC (κw= 0·90; 95 % CI 0·87, 0·92). However, Kuwaiti reference data showed the lowest agreement with the three international approaches, the poorest being with WHO 2007 (κw= 0·54; 95 % CI 0·49, 0·59).

Conclusions

Caution should be exercised when using recently collected national reference data and definitions while assessing underweight, overweight and obesity for clinical and public health applications.
Comparison of measured rain attenuation and ITU-R predictions on experimental microwave links in Malaysia
Authors: Abdulrahman Amuda Yusuf , bin Abdulrahman Tharek , bin Abdulrahim Sharul Kamal , Kesavan Ulaganathen
Published: July 2011

This paper presents the results of direct rain attenuation measurements carried out on four experimental microwave links, installed at UTM, Malaysia. The links operate at frequencies of 15, 22, 26, and 38 GHz and the cumulative distribution function for different rain rates have been generated from the measured 4-year rain gauge data. The experimentally measured attenuation data have been compared with International Telecommunication Unior-R rain attenuation predictions; and it has been found that the latter have underestimated the measured values, especially at higher rain rates. The deviations have been modeled as a function of rain rate exceedances R%p. It is hoped that the study will provide useful information for estimation of rainfall attenuation on microwave links in tropical regions that have similar situation to Malaysia.
New perspectives on Natal Pulses from satellite observations
Authors: Krug M. , Penven P.
Published: July 2011

More than 6 years of high‐frequency sea surface temperature (SST) imagery are used to follow perturbations at the inshore front of the Agulhas Current, between the northern Natal Bight and Port Elizabeth. Selected case studies as well as a front detection algorithm applied to the SST data provide some new insights into the dynamics of Natal Pulses and the variability of the northern Agulhas Current. Over the measurement period, the path of the Agulhas Current's inshore front does not exhibit any seasonality. Instead, large excursions in the Agulhas Current's inshore front are dominated by the intermittent passage of offshore cyclonic meanders from the Natal Bight and Port Edward regions to Port Elizabeth. SST imagery reveals that as they progress downstream, Natal Pulses interact with the topography to form secondary offshore meanders which propagate in the lee of the original perturbation. Over time, these secondary meanders dissipate, remerge with the original Natal Pulse, or detach from the Agulhas Current. Fluctuations in the Agulhas Current inshore path do not display the same frequency characteristics at all transects. From the northern Natal Bight to Port Edward both the size and frequency of Natal Pulses increases, while south of Port Edward the number of Natal Pulses decreases. At Port Elizabeth, the number of Natal Pulses observed is lower in comparison to previous estimates, with an average of 1.6 Natal Pulses per year.
The death receptor CD95 activates the cofilin pathway to stimulate tumour cell invasion
Authors: Steller Ernst J A , Ritsma Laila , Raats Danielle A E , Hoogwater Frederik J H , Emmink Benjamin L , Govaert Klaas M , Laoukili Jamila , Borel Rinkes Inne H M , van Rheenen Jacco , Kranenburg Onno
Published: July 2011

The death receptor CD95 promotes apoptosis through well‐defined signalling pathways. In colorectal cancer cells, CD95 primarily stimulates migration and invasion through pathways that are incompletely understood. Here, we identify a new CD95‐activated tyrosine kinase pathway that is essential for CD95‐stimulated tumour cell invasion. We show that CD95 promotes Tyr 783 phosphorylation of phospholipase C‐γ1 through the platelet‐derived growth factor receptor‐β, resulting in ligand‐stimulated phosphatidylinositol (4,5)‐bisphosphate (PIP2) hydrolysis. PIP2 hydrolysis liberates the actin‐severing protein cofilin from the plasma membrane to initiate cortical actin remodelling. Cofilin activation is required for CD95‐stimulated formation of membrane protrusions and increased tumour cell invasion.
Progressive methylation of ageing histones by Dot1 functions as a timer
Authors: De Vos Dirk , Frederiks Floor , Terweij Marit , van Welsem Tibor , Verzijlbergen Kitty F , Iachina Ekaterina , de Graaf Erik L , Maarten Altelaar A F , Oudgenoeg Gideon , Heck Albert J R , Krijgsveld Jeroen , Bakker Barbara M , van Leeuwen Fred
Published: July 2011

Post‐translational modifications of histone proteins have a crucial role in regulating gene expression. If efficiently re‐established after chromosome duplication, histone modifications could help propagate gene expression patterns in dividing cells by epigenetic mechanisms. We used an integrated approach to investigate the dynamics of the conserved methylation of histone H3 Lys 79 (H3K79) by Dot1. Our results show that methylation of H3K79 progressively changes after histone deposition, which is incompatible with a rapid copy mechanism. Instead, methylation accumulates on ageing histones, providing the cell with a timer mechanism to directly couple cell‐cycle length to changes in chromatin modification on the nucleosome core.
Site recognition and substrate screens for PKN family proteins
Authors: Collazos Alejandra , Michael Nicholas , Whelan Richard D. H. , Kelly Gavin , Mellor Harry , Pang Leon C. H. , Totty Nick , Parker Peter J.
Published: July 2011

The PRKs [protein kinase C-related kinases; also referred to as PKNs (protein kinase Ns)] are a kinase family important in diverse functions including migration and cytokinesis. In the present study, we have re-evaluated and compared the specificity of PKN1 and PKN3 and assessed the predictive value in substrates. We analysed the phosphorylation consensus motif of PKNs using a peptide library approach and demonstrate that both PKN1 and PKN3 phosphorylate serine residues in sequence contexts that have an arginine residue in position −3. In contrast, PKN1 and PKN3 do not tolerate arginine residues in position +1 and −1 respectively. To test the predictive value of this motif, site analysis was performed on the PKN substrate CLIP-170 (cytoplasmic linker protein of 170 kDa); a PKN target site was identified that conformed to the predicted pattern. Using a protein array, we identified 22 further substrates for PKN1, of which 20 were previously undescribed substrates. To evaluate further the recognition signature, the site on one of these hits, EGFR (epidermal growth factor receptor), was identified. This identified Thr654 in EGFR as the PKN1 phosphorylation site and this retains an arginine residue at the −3 position. Finally, the constitutive phosphorylation of EGFR on Thr654 is shown to be modulated by PKN in vivo.
Acetylsalicylic acid regulates overexpressed small GTPase RhoA in vascular smooth muscle cells through prevention of new synthesis and enhancement of protein degradation
Authors: Li Dong-Bo , Fu Zhi-Xuan , Ruan Shu-Qin , Hu Shen-Jiang , Li Xia
Published: July 2011

RhoA has been shown to play a major role in vascular processes and acetylsalicylic acid (aspirin) is known to exert a cytoprotective effect via multiple mechanisms. In the present study, we aimed at investigating the effect of aspirin on RhoA expression under a stress state in rat VSMCs (vascular smooth muscle cells) and the underlying mechanisms. The expression of iNOS (inducible nitric oxide synthase) and iNOS activity as well as NO concentration was significantly promoted by LPS (lipopolysaccharide) accompanying the elevation of RhoA expression, which was blocked by the addition of the iNOS inhibitor L-NIL [L-N6-(1-iminoethyl)lysine dihydrochloride]. Aspirin (30 μM) significantly attenuated the elevation of RhoA, while indomethacin and salicylate had no similar effect. The sGC (soluble guanylate cyclase) inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) showed the same effect as aspirin in down-regulating RhoA but was reversed by the addition of the cGMP analogue 8-Br-PET-cGMP (β-phenyl-1,N2-ethano-8-bromoguanosine 3′,5′-cyclic monophosphorothioate). 8-Br-PET-cGMP solely enhanced the RhoA expression that was abrogated by preincubation with aspirin. Degradation analysis indicated that aspirin enhanced the protein degradation rate of RhoA and GDP-bound RhoA seemed to be more susceptible to aspirin-enhanced degradation compared with the GTP-bound form. Our results indicate that aspirin attenuates the LPS-induced overexpression of RhoA both by inhibiting new synthesis and accelerating protein degradation, which may help elucidate the multiple beneficial effects of aspirin.
Inhibition of cell growth and up-regulation of MAD2 in human oesophageal squamous cell carcinoma after treatment with the Src/Abl inhibitor dasatinib
Authors: Wang Li , Guo Bin , Wang Ruwen , Jiang Yaoguang , Qin Shukui , Liang Shuhui , Zhao Yunping , Guo Wei , Li Kun , Fan Xiaoqing
Published: July 2011

Aberrant expression and/or activity of the non-receptor protein tyrosine kinase SFK (Src family kinase) members are commonly observed in progressive stages of human tumours. The aim of the present study was to investigate whether Src is a potential drug target for treating oesophageal squamous cell carcinoma. Compared with the human immortalized oesophageal epithelial cell line SHEE, oesophageal squamous cell carcinoma cells have increased tyrosine phosphorylation activities. We have explored the therapeutic potential of dasatinib, a small-molecule inhibitor that targets multiple cytosolic and membrane-bound tyrosine kinases, for the treatment of oesophageal squamous cell carcinoma. We examined that the effects of dasatinib on proliferation, invasion, apoptosis, spindle checkpoint, cell-cycle arrest and kinase activity in vitro using three human oesophageal carcinoma cell lines KYSE30, KYSE180 and EC109. In nude mouse models, dasatinib treatment effectively inhibited the expression of activated Src, resulting in the inhibition of tumour growth. Multiple drug effect isobologram analysis was used to study interactions with the chemotherapeutic drug docetaxel. As expected, the three oesophageal carcinoma cell lines were highly sensitive to dasatinib, but SHEE cells were not sensitive to this drug. Concentration-dependent anti-proliferative effects of dasatinib were observed in the three oesophageal carcinoma cell lines. Dasatinib significantly inhibited oesophageal carcinoma cell invasion and up-regulation of MAD2 (mitotic arrest-deficient 2), as well as inducing cell apoptosis and cell-cycle arrest. Additive and synergistic interactions were observed for the combination of dasatinib and docetaxel. Therefore it was concluded that dasatinib blocks the G1/S transition and inhibits cell growth. These results provided a clear biological rationale to test dasatinib as a single agent or in combination with chemotherapy in oesophageal squamous cell carcinoma. Moreover, we have shown in vitro and in vivo that dasatinib might have therapeutic benefit for patients with oesophageal squamous cell carcinoma who are not eligible for surgery.
Modeling hydrodynamic self-propulsion with Stokesian Dynamics. Or teaching Stokesian Dynamics to swim
Authors: Swan James W. , Brady John F. , Moore Rachel S. ,   ChE 174
Published: July 2011

We develop a general framework for modeling the hydrodynamic self-propulsion (i.e., swimming) of bodies (e.g., microorganisms) at low Reynolds number via Stokesian Dynamics simulations. The swimming body is composed of many spherical particles constrained to form an assembly that deforms via relative motion of its constituent particles. The resistance tensor describing the hydrodynamic interactions among the individual particles maps directly onto that for the assembly. Specifying a particular swimming gait and imposing the condition that the swimming body is force- and torque-free determine the propulsive speed. The body’s translational and rotational velocities computed via this methodology are identical in form to that from the classical theory for the swimming of arbitrary bodies at low Reynolds number. We illustrate the generality of the method through simulations of a wide array of swimming bodies: pushers and pullers, spinners, the Taylor/Purcell swimming toroid, Taylor’s helical swimmer, Purcell’s three-link swimmer, and an amoeba-like body undergoing large-scale deformation. An open source code is a part of the supplementary material and can be used to simulate the swimming of a body with arbitrary geometry and swimming gait.
Weibel instability and structures of magnetic island in anti-parallel collisionless magnetic reconnection
Authors: Lu San , Lu Quanming , Shao Xi , Yoon Peter H. , Wang Shui
Published: July 2011

Two-dimensional (2D) particle-in-cell simulations are performed to investigate the structures of the out-of-plane magnetic field in magnetic island, which is produced during anti-parallel collisionless magnetic reconnection. Regular structures with alternate positive and negative values of the out-of-plane magnetic field along the x direction are formed in magnetic island. The generation mechanism of such structures is also proposed in this paper, which is due to the Weibel instability excited by the temperature anisotropy in magnetic island.
Energy transfer versus charge separation in hybrid systems of semiconductor quantum dots and Ru-dyes as potential co-sensitizers of TiO2-based solar cells
Authors: Giménez Sixto , Rogach Andrey L. , Lutich Andrey A. , Gross Dieter , Poeschl Andreas , Susha Andrei S. , Mora-Seró Ivan , Lana-Villarreal Teresa , Bisquert Juan
Published: July 2011

Hybrid structures of colloidal quantum dots (QDs) with Ru-dyes have been studied as candidates for panchromatic sensitizers for TiO2-based solar cells. Steady-state and time resolved photoluminescence spectroscopy and photocurrent measurements have been employed to identify the prevailing transfer mechanisms for photogenerated excitons between CdSe QDs capped with a traditional bulky organic ligand trioctylphosphine and Ru-dyes (N3 or Ru505) deposited onto inert glass or mesoporous TiO2 substrates. The type II energy level alignment between the QDs and both N3 and Ru505 offers a possibility for the directional charge separation, with electrons transferred to the QDs and holes to the dye. This scenario is indeed valid for the QD/Ru505 and TiO2/QD/Ru505 hybrid systems, with the negligible spectral overlap between the emission of the QDs and the absorption of the Ru505 dye. For the QD/N3 and TiO2/QD/N3 hybrid systems, the spectral overlap favors the longer range energy transfer from the QDs to N3, independently of the presence of the electron acceptor TiO2.
Frictional slip lengths for unidirectional superhydrophobic grooved surfaces
Authors: Crowdy Darren
Published: July 2011

The exact solutions due to Philip [ZAMP 23, 353 (1972)] for Stokes shear flow over a periodic array of no-shear slots embedded in a no-slip surface are generalized to account for an arbitrary pattern of no-shear slots in each period window. The slots, or grooves, in each period window run parallel to each other, and are of infinite length, but their widths and separations can be specified arbitrarily. Explicit solutions are found both for longitudinal and transverse flows over the composite grooved surface. Analytical expressions for the transverse and longitudinal slip lengths associated with the microstructured surfaces are then found as functions of the geometrical parameters characterizing the surface. The formulae are relevant to a wide class of flow geometries and are expected to provide a useful tool in the design, analysis, and optimization of the friction properties of grooved microstructured superhydrophobic surfaces. The results are used to show that introducing even a very small wetted region in a no-shear slot can have a significant influence on the effective slip length.
Conditions for microwave amplification due to spin-torque dynamics in magnetic tunnel junctions
Authors: Xue Lin , Wang Chen , Cui Yong-Tao , Katine J. A. , Buhrman R. A. , Ralph D. C.
Published: July 2011

Spin torque from a microwave current flowing through a magnetic tunnel junction (MTJ) can excite resonant magnetic dynamics and hence resistance oscillations. When a DC current is also applied, the MTJ produces an oscillating voltage at the frequency of the input signal. This oscillating voltage increases with DC bias and can in principle become larger than the input signal, yielding amplification. We analyze how to design tunnel junction devices to achieve gains larger than one.
Microwave cavities for vapor cell frequency standards
Authors: Godone Aldo , Micalizio Salvatore , Levi Filippo , Calosso Claudio
Published: July 2011

In this paper, we report an analysis of the design criteria of microwave cavities for vapor cell frequency standards. Two main geometries exploited in those devices are considered: the cylindrical cavity, used, for example, in the coherent population trapping maser and in the pulsed optically pumped (POP) clock, and the spherical cavity used in the isotropically laser cooled clock. The cavity behavior is described through a lumped equivalent circuit in which the input coupling loop, the dielectric cell containing the atoms and the diodes for frequency tuning or Q control are taken into account. In particular, the effect of the cell on the cavity resonance frequency is analytically evaluated via a first-order perturbation approach. The theory is found in good agreement with the experiments performed with two different cylindrical cavities used for the POP clock; the model here developed can then be helpful in the design of the cavity system. The general principles here reported can be adapted to other standards, such as atomic fountains and hydrogen masers, and to other modes and/or geometries.
Effect of microstructure on the thermal conductivity of disordered carbon
Authors: Suarez-Martinez I. , Marks N. A.
Published: July 2011

Computational methods are used to control the degree of structural order in a variety of carbon materials containing primarily sp2 bonding. Room-temperature thermal conductivities are computed using non-equilibrium molecular dynamics. Our results reproduce experimental data for amorphous and glassy carbons and confirm previously proposed structural models for vitreous carbons. An atomistic model is developed for highly oriented thin films seen experimentally, with a maximum computed thermal conductivity of 35 W m−1 K−1. This value is much higher than that of the amorphous and glassy structures, demonstrating that the microstructure influences the thermal conductivity more strongly than the density.
Stability and crossover of 71° and 109° domains influenced by the film thickness and depolarization field in rhombohedral ferroelectric thin films
Authors: Huang C. W. , Chen Z. H. , Wang Junling , Sritharan T. , Chen Lang
Published: July 2011

The stability of domain patterns in rhombohedral ferroelectric films was studied using the minimum of free energy consisting of electrostatic and elastic energies. The converse piezoelectric effect due to the residual depolarization field was also considered. In the open-circuit condition, the 109° domain is more stable than the 71° one, which has a large depolarization field energy. By gradually decreasing the depolarization field energy, the stable domain pattern changes from 109° to 71° at a critical film thickness. This critical thickness of crossover from 109° to 71° domains is predicted to decrease with increasing residual depolarization field.
High contrast imaging and thickness determination of graphene with in-column secondary electron microscopy
Authors: Kochat Vidya , Nath Pal Atindra , Sneha E. S. , Sampathkumar Arjun , Gairola Anshita , Shivashankar S. A. , Raghavan Srinivasan , Ghosh Arindam
Published: July 2011

We report a new method for quantitative estimation of graphene layer thicknesses using high contrast imaging of graphene films on insulating substrates with a scanning electron microscope. By detecting the attenuation of secondary electrons emitted from the substrate with an in-column low-energy electron detector, we have achieved very high thickness-dependent contrast that allows quantitative estimation of thickness up to several graphene layers. The nanometer scale spatial resolution of the electron micrographs also allows a simple structural characterization scheme for graphene, which has been applied to identify faults, wrinkles, voids, and patches of multilayer growth in large-area chemical vapor deposited graphene. We have discussed the factors, such as differential surface charging and electron beam induced current, that affect the contrast of graphene images in detail.
Temperature dependence of the magnetic properties of L11-type Co–Ni–Pt ordered alloy films for thermally assisted recording media
Authors: Sayama Junichi , Shimatsu Takehito , Nemoto Hiroaki , Okamoto Satoshi , Kitakami Osamu , Aoi Hajime
Published: July 2011

We developed L11-type Co–Ni–Pt ordered alloy films for use as a material for creating thermally assisted magnetic recording media with high recording densities. We examined the temperature dependence of magnetic properties of L11-type (Co1−xNix)50Pt50 ordered alloy films. These films had a uniaxial magnetic anisotropy of 107 erg/cm3 at an x of less than ∼ 0.8. The Curie point was monotonously reduced when the Ni content steadily increased. The composition of Co15Ni35Pt50 (x = 0.7) provided both a high magnetic anisotropy of 1.4 × 107 erg/cm3 and a low Curie point of 583 K, which are favorable for thermally assisted magnetic recording media.
Quantum diffusive dynamics of macromolecular transitions
Authors: Beccara S. a , Garberoglio G. , Faccioli P.
Published: July 2011

We study the role of quantum fluctuations of atomic nuclei in the real-time dynamics of non-equilibrium macro-molecular transitions. To this goal we introduce an extension of the dominant reaction pathways formalism, in which the quantum corrections to the classical overdamped Langevin dynamics are rigorously taken into account to order ℏ2. We first illustrate our approach in simple cases, and compare with the results of the instanton theory. Then we apply our method to study the C7eq → C7ax transition of alanine dipeptide. We find that the inclusion of quantum fluctuations can significantly modify the reaction mechanism for peptides. For example, the energy difference which is overcome along the most probable pathway is reduced by as much as 50%.