Why Are Male Social Relationships Complex in the Doubtful Sound Bottlenose Dolphin Population?

Copyright 2008 Elsevier B.V., All rights reserved.Peer reviewedPublisher PD

Preparation methods of chitosan nanoparticles: a review

El quitosano es un polisacárido natural que ha sido utilizado frecuentemente en el desarrollo de distintos materiales, debido a sus excepcionales propiedades fisicoquímicas y biológicas. Las nanopartículas de quitosano son generalmente producidas por estrategias denominadas de construcción (del inglés “bottom up”), donde el ensamblado polimérico es promovido por distintas interacciones moleculares. Sin embargo, un grupo de estrategias llamadas de deconstrucción (del inglés “top-down”) basadas en la fragmentación de estructuras macroscópicas, han generado un gran interés recientemente como alternativa para la obtención de nanomateriales. El presente trabajo hace una revisión bibliográfica de los resultados obtenidos por distintas investigaciones sobre la producción de sistemas de nanopartículas basadas en quitosano durante las últimas décadas. Las evidencias demostraron que las nanopartículas de quitosano juegan un papel preponderante en la investigación de los nanomateriales poliméricos con aplicaciones biomédicas y farmacéuticas, debido a la gran diversidad de métodos de obtención existentes que determinan las propiedades de los materiales, tales como tamaño de partícula, capacidad de incorporación y liberación de compuestos bioactivos, carga superficial, mucoadhesividad, entre otras

Spatial Guilds in the Serengeti Food Web Revealed by a Bayesian Group Model

Food webs, networks of feeding relationships among organisms, provide fundamental insights into mechanisms that determine ecosystem stability and persistence. Despite long-standing interest in the compartmental structure of food webs, past network analyses of food webs have been constrained by a standard definition of compartments, or modules, that requires many links within compartments and few links between them. Empirical analyses have been further limited by low-resolution data for primary producers. In this paper, we present a Bayesian computational method for identifying group structure in food webs using a flexible definition of a group that can describe both functional roles and standard compartments. The Serengeti ecosystem provides an opportunity to examine structure in a newly compiled food web that includes species-level resolution among plants, allowing us to address whether groups in the food web correspond to tightly-connected compartments or functional groups, and whether network structure reflects spatial or trophic organization, or a combination of the two. We have compiled the major mammalian and plant components of the Serengeti food web from published literature, and we infer its group structure using our method. We find that network structure corresponds to spatially distinct plant groups coupled at higher trophic levels by groups of herbivores, which are in turn coupled by carnivore groups. Thus the group structure of the Serengeti web represents a mixture of trophic guild structure and spatial patterns, in contrast to the standard compartments typically identified in ecological networks. From data consisting only of nodes and links, the group structure that emerges supports recent ideas on spatial coupling and energy channels in ecosystems that have been proposed as important for persistence.Comment: 28 pages, 6 figures (+ 3 supporting), 2 tables (+ 4 supporting

Comparative Genomics of Bordetella pertussis Reveals Progressive Gene Loss in Finnish Strains

BACKGROUND: Bordetella pertussis is a gram-negative bacterium that infects the human respiratory tract and causes pertussis or whooping cough. The disease has resurged in many countries including Finland where the whole-cell pertussis vaccine has been used for more than 50 years. Antigenic divergence has been observed between vaccine strains and clinical isolates in Finland. To better understand genome evolution in B. pertussis circulating in the immunized population, we developed an oligonucleotide-based microarray for comparative genomic analysis of Finnish strains isolated during the period of 50 years. METHODOLOGY/PRINCIPAL FINDINGS: The microarray consisted of 3,582 oligonucleotides (70-mer) and covered 94% of 3,816 ORFs of Tohama I, the strain of which the genome has been sequenced. Twenty isolates from 1953 to 2004 were studied together with two Finnish vaccine strains and two international reference strains. The isolates were selected according to their characteristics, e.g. the year and place of isolation and pulsed-field gel electrophoresis profiles. Genomic DNA of the tested strains, along with reference DNA of Tohama I strain, was labelled and hybridized. The absence of genes as established with microarrays, was confirmed by PCR. Compared with the Tohama I strain, Finnish isolates lost 7 (8.6 kb) to 49 (55.3 kb) genes, clustered in one to four distinct loci. The number of lost genes increased with time, and one third of lost genes had functions related to inorganic ion transport and metabolism, or energy production and conversion. All four loci of lost genes were flanked by the insertion sequence element IS481. CONCLUSION/SIGNIFICANCE: Our results showed that the progressive gene loss occurred in Finnish B. pertussis strains isolated during a period of 50 years and confirmed that B. pertussis is dynamic and is continuously evolving, suggesting that the bacterium may use gene loss as one strategy to adapt to highly immunized populations

Teaching Tolerance in a Globalized World: Final Remarks

Each of the five empirical studies presented in this report aimed to identify factors and conditions that help schools and teachers to promote tolerance in a globalized world. Each study acknowledged the complex, hierarchical layers of explanatory mechanisms, while focusing on what could be learned from in-depth analysis of data collected by the International Association for the Evaluation ofEducational Achievement’s International Civic and Citizenship Education Study 2009. In this chapter, key findings are summarized, while acknowledging limitations and caveats, and avenues for further research are identified. The report findings also flag some potential implications for policymakers

Fibromyalgia and neuropathic pain - differences and similarities. A comparison of 3057 patients with diabetic painful neuropathy and fibromyalgia

<p>Abstract</p> <p>Background</p> <p>Patients with diabetic neuropathy (DPN) and fibromyalgia differ substantially in pathogenetic factors and the spatial distribution of the perceived pain. We questioned whether, despite these obvious differences, similar abnormal sensory complaints and pain qualities exist in both entities. We hypothesized that similar sensory symptoms might be associated with similar mechanisms of pain generation. The aims were (1) to compare epidemiological features and co-morbidities and (2) to identify similarities and differences of sensory symptoms in both entities.</p> <p>Methods</p> <p>The present multi-center study compares epidemiological data and sensory symptoms of a large cohort of 1434 fibromyalgia patients and 1623 patients with painful diabetic neuropathy. Data acquisition included standard demographic questions and self-report questionnaires (MOS sleep scale, PHQ-9, Pain<it>DETECT</it>). To identify subgroups of patients with characteristic combinations of symptoms (sensory profiles) a cluster analysis was performed using all patients in both cohorts.</p> <p>Results</p> <p>Significant differences in co-morbidities (depression, sleep disturbance) were found between both disorders. Patients of both aetiologies chose very similar descriptors to characterize their sensory perceptions. Burning pain, prickling and touch-evoked allodynia were present in the same frequency. Five subgroups with distinct symptom profiles could be detected. Two of the subgroups were characteristic for fibromyalgia whereas one profile occurred predominantly in DPN patients. Two profiles were found frequently in patients of both entities (20-35%).</p> <p>Conclusions</p> <p>DPN and fibromyalgia patients experience very similar sensory phenomena. The combination of sensory symptoms - the sensory profile - is in most cases distinct and almost unique for each one of the two entities indicating aetiology-specific mechanisms of symptom generation. Beside the unique aetiology-specific sensory profiles an overlap of sensory profiles can be found in 20-35% of patients of both aetiologies.</p

Effective Rheology of Bubbles Moving in a Capillary Tube

We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

Ectopic hbox12 Expression Evoked by Histone Deacetylase Inhibition Disrupts Axial Specification of the Sea Urchin Embryo

Dorsal/ventral patterning of the sea urchin embryo depends upon the establishment of a Nodal-expressing ventral organizer. Recently, we showed that spatial positioning of this organizer relies on the dorsal-specific transcription of the Hbox12 repressor. Building on these findings, we determined the influence of the epigenetic milieu on the expression of hbox12 and nodal genes. We find that Trichostatin-A, a potent and selective histone-deacetylases inhibitor, induces histone hyperacetylation in hbox12 chromatin, evoking broad ectopic expression of the gene. Transcription of nodal concomitantly drops, prejudicing dorsal/ventral polarity of the resulting larvae. Remarkably, impairing hbox12 function, either in a spatially-restricted sector or in the whole embryo, specifically rescues nodal transcription in Trichostatin-A-treated larvae. Beyond strengthen the notion that nodal expression is not allowed in the presence of functional Hbox12 in the same cells, these results highlight a critical role of histone deacetylases in regulating the spatial expression of hbox12

Effects of immunomodulatory treatment with subcutaneous interferon beta-1a oncognitive decline in mildly disabled patients with relapsing-remitting multiple sclerosis

The objective of this study was to assess the effects of subcutaneous (sc) interferon beta-1a (IFNbeta-1a) on cognition in mildly disabled patients with relapsing-remitting multiple sclerosis (RRMS). Patients aged 18-50 years with RRMS (McDonald criteria; Expanded Disability Status Scale score <or=4.0) were assigned IFNbeta therapy at the physician's discretion and underwent standardized magnetic resonance imaging, neurological examination and neuropsychological testing at the baseline and regular intervals for up to three years. This analysis included 459 patients who received sc IFNbeta-1a (44 mcg: n = 236; 22 mcg: n = 223; three-year follow up was available for 318 patients). The hazard ratio for cognitive impairment over three years (44 mcg versus 22 mcg) was 0.68 (95% confidence interval [CI]: 0.480-0.972), suggesting a 32% lower risk with the higher dose treatment. At year 3, the proportion of patients who were cognitively impaired increased slightly from 23.5% at the baseline to 24.8% in the IFNbeta-1a 22 mcg treatment group, but remained stable at 15.2% in the IFNbeta-1a 44 mcg treatment group. The proportion of patients with cognitive impairment at year 3 was significantly higher in the 22 mcg group than in the 44 mcg group (P = 0.03), although a trend was also seen at the baseline (P = 0.058). Multivariate logistic regression (corrected for baseline cognitive deficits) indicated that treatment with the higher dose of IFNbeta-1a was predictive of lower cognitive impairment at three years (odds ratio: 0.51, 95% CI: 0.26-0.99) compared with the lower dose of IFNbeta-1a. These findings suggest that sc IFNbeta-1a may have dose-dependent cognitive benefits in mildly disabled patients with RRMS, and may support early initiation of high-dose IFNbeta-1a treatment