bluuebunny/crossref_metadata_2025 huggingface dataset:
Surgical optimization and characterization of a minimally invasive aortic banding procedure to induce cardiac hypertrophy in mice
Authors: Martin Tamara P. , Robinson Emma , Harvey Adam P. , MacDonald Margaret , Grieve David J. , Paul Andrew , Currie Susan
Published: March 2012

Left ventricular pressure overload in response to aortic banding is an invaluable model for studying progression of cardiac hypertrophy and transition to heart failure. Traditional aortic banding has recently been superceded by minimally invasive transverse aortic banding (MTAB), which does not require ventilation so is less technically challenging. Although the MTAB approach is superior, few laboratories have documented success, and minimal information on the model is available. The aim of this study was to optimize conditions for MTAB and to characterize the development and progression of cardiac hypertrophy. Isofluorane proved the most suitable anaesthetic for MTAB surgery in mice, and 1 week after surgery the MTAB animals showed significant increases in systolic blood pressure (MTAB 110 ± 6 mmHg versus sham 78 ± 3 mmHg, n= 7, P < 0.0001) and heart weight to body weight ratio (MTAB 6.2 ± 0.2 versus sham 5.1 ± 0.1, n= 12, P < 0.001), together with systolic (e.g. fractional shortening, MTAB 31.7 ± 1%versus sham 36.6 ± 1.4%, P= 0.01) and diastolic dysfunction (e.g. left ventricular end‐diastolic pressure, MTAB 12.7 ± 1.0 mmHg versus sham 6.7 ± 0.8 mmHg, P < 0.001). Leucocyte infiltration to the heart was evident after 1 week in MTAB hearts, signifying an inflammatory response. More pronounced remodelling was observed 4 weeks postsurgery (heart weight to body weight ratio, MTAB 9.1 ± 0.6 versus sham 4.6 ± 0.04, n= 10, P < 0.0001) and fractional shortening was further decreased (MTAB 24.3 ± 2.5%versus sham 43.6 ± 1.7%, n= 10, P= 0.003), together with a significant increase in cardiac fibrosis and further cardiac inflammation. Our findings demonstrate that MTAB is a relevant experimental model for studying development and progression of cardiac hypertrophy, which will be highly valuable for future studies examining potential novel therapeutic interventions in this setting.
Numerical Simulation of an Oscillating Cylinder Using Large Eddy Simulation and Implicit Large Eddy Simulation
Authors: Feymark A. , Alin N. , Bensow R. , Fureby C.
Published: March 2012

In this work, we use large eddy simulation (LES) to study the influence of grid and subgrid model on the lift and drag force predictions of a fixed cylinder undergoing streamwise sinusoidal oscillations in a steady flow, resulting in a varying Reynolds number, Re, within the range 405 ≤ Re ≤ 2482. This benchmark case is a first step toward studying engineering applications related to flow-induced vibrations. We examine the influence of both grid resolution and the subgrid model using implicit and explicit LES. The methodology used, LES based on a finite-volume method capable of handling moving meshes, are found to provide force predictions that agree well with experimentally measured data, with respect both to the overall flow development and force magnitude.
Analytic determination of the mean free path of sequential reactions
Authors: Alderson Eric C. , Santarius John F.
Published: March 2012

The concept of mean free path has been in use since 1858 as a way to determine the average path length in which a collision and related reactions will occur. The derivation of a collision mean free path typically treats the average path length for a single collision. There are a number of instances where a series of collisions and reactions produce a product of interest, yet a means to determine the average path length for a series of reactions is not apparent in the literature. This paper will review the derivation of mean free path for a single collision, then extend the derivation to the mean free path for two and three collisions in sequence, and finally discuss how this derivation can be extended to an arbitrary number of collisions.
Effects of Airflow and Changing Humidity on the Aerosolization of Respirable Fungal Fragments and Conidia of Botrytis cinerea
Authors: Madsen Anne Mette
Published: March 2012

The purpose of this study was to investigate the aerosolization of particles (micro- and macroconidia and fragments) from
Botrytis cinerea
cultures in relation to potential human inhalation in indoor environments. The influence of the following factors on the aerosolization of
B. cinerea
particles was studied: exposure to airflow, relative humidity (rh), changing rh, and plant or building materials. The aerodynamic diameter (
d

a

) and the respirable fraction of the aerosolized particles were determined. Conidia and fragments of
B. cinerea
were not aerosolized as a response to a decrease in the rh. In contrast, both micro- and macroconidia and fungal fragments were aerosolized when exposed to an airflow of 1.5 m s
−1
or 0.5 m s
−1
. Significantly more particles of microconidial size and fragment size were aerosolized at a low rh (18 to 40% rh) than at a higher rh (60 to 80% rh) when cultures were exposed to airflow. The size of the respirable fraction of the aerosolized particles was dependent on the rh but not on the growth material. At high rh, about 30% of the aerosolized particles were of respirable size, while at low rh, about 70% were of respirable size. During low rh, more fungal (1→3)-β-
d
-glucan and chitinase were aerosolized than during high rh. In conclusion, exposure to external physical forces such as airflow is necessary for the aerosolization of particles from
B. cinerea
. The amount and size distribution are highly affected by the rh, and more particles of respirable sizes were aerosolized at low rh than at high rh.
Modular Glucuronoxylan-Specific Xylanase with a Family CBM35 Carbohydrate-Binding Module
Authors: Valenzuela Susana Valeria , Diaz Pilar , Pastor F. I. Javier
Published: March 2012

Xyn30D from the xylanolytic strain
Paenibacillus barcinonensis
has been identified and characterized. The enzyme shows a modular structure comprising a catalytic module family 30 (GH30) and a carbohydrate-binding module family 35 (CBM35). Like GH30 xylanases, recombinant Xyn30D efficiently hydrolyzed glucuronoxylans and methyl-glucuronic acid branched xylooligosaccharides but showed no catalytic activity on arabinose-substituted xylans. Kinetic parameters of Xyn30D were determined on beechwood xylan, showing a

K
m

of 14.72 mg/ml and a
k
cat
value of 1,510 min
−1
. The multidomain structure of Xyn30D clearly distinguishes it from the GH30 xylanases characterized to date, which are single-domain enzymes. The modules of the enzyme were individually expressed in a recombinant host and characterized. The isolated GH30 catalytic module showed specific activity, mode of action on xylan, and kinetic parameters that were similar to those of the full-length enzyme. Computer modeling of the three-dimensional structure of Xyn30D showed that the catalytic module is comprised of a common (β/α)
8
barrel linked to a side-associated β-structure. Several derivatives of the catalytic module with decreasing deletions of this associated structure were constructed. None of them showed catalytic activity, indicating the importance of the side β-structure in the catalysis of Xyn30D. Binding properties of the isolated carbohydrate-binding module were analyzed by affinity gel electrophoresis, which showed that the CBM35 of the enzyme binds to soluble glucuronoxylans and arabinoxylans. Analysis by isothermal titration calorimetry showed that CBM35 binds to glucuronic acid and requires calcium ions for binding. Occurrence of a CBM35 in a glucuronoxylan-specific xylanase is a differential trait of the enzyme characterized.
EscA Is a Crucial Component of the Type III Secretion System of Enteropathogenic Escherichia coli
Authors: Sal-Man Neta , Biemans-Oldehinkel Esther , Sharon David , Croxen Matthew A. , Scholz Roland , Foster Leonard J. , Finlay B. Brett
Published: March 2012

The virulence of many Gram-negative pathogens is associated with type III secretion systems (T3SSs), which deliver virulence effector proteins into the cytoplasm of host cells. Components of enteropathogenic
Escherichia coli
(EPEC) T3SS are encoded within the locus of enterocyte effacement (LEE). While most LEE-encoded T3SS proteins in EPEC have assigned names and functions, a few of them remain poorly characterized. Here, we studied a small LEE-encoded protein, Orf15, that shows no homology to other T3SS/flagellar proteins and is only present in attaching and effacing pathogens, including enterohemorrhagic
E. coli
and
Citrobacter rodentium
. Our findings demonstrated that it is essential for type III secretion (T3S) and that it is localized to the periplasm and associated with the inner membrane. Membrane association was driven by the N-terminal 19 amino acid residues, which were also shown to be essential for T3S. Consistent with its localization, Orf15 was found to interact with the EPEC T3SS outer membrane ring component, EscC, which was previously shown to be embedded within the outer membrane and protruding into the periplasmic space. Interestingly, we found that the predicted coiled-coil structure of Orf15 is critical for the protein's function. Overall, our findings suggest that Orf15 is a structural protein that contributes to the structural integrity of the T3S complex, and therefore we propose to rename it EscA.
TGF-β and Smad3 modulate PI3K/Akt signaling pathway in vascular smooth muscle cells
Authors: Suwanabol Pasithorn A. , Seedial Stephen M. , Zhang Fan , Shi Xudong , Si Yi , Liu Bo , Kent K. Craig
Published: March 2012

Transforming growth factor-β (TGF-β) is upregulated at the time of arterial injury; however, the mechanism through which TGF-β enhances the development of intimal hyperplasia is not clear. Recent studies from our laboratory suggest that in the presence of elevated levels of Smad3, TGF-β stimulates smooth muscle cell (SMC) proliferation. This is a novel phenomenon in that TGF-β has traditionally been known as a potent inhibitor of cellular proliferation. In these studies we explore the signaling pathways through which TGF-β mediates its proliferative effect in vascular SMCs. We found that TGF-β phosphorylates and activates Akt in a time-dependent manner, and this effect is significantly enhanced by overexpression of Smad3. Furthermore, both chemical and molecular inhibition of Smad3 can reverse the effect of TGF-β on Akt. Although we found numerous signaling pathways that might function as intermediates between Smad3 and Akt, p38 appeared the most promising. Overexpression of Smad3 enhanced p38 phosphorylation and inhibition of p38 with a chemical inhibitor or a small interfering RNA blocked TGF-β-induced Akt phosphorylation. Moreover, TGF-β/Smad3 enhancement of SMC proliferation was blocked by inhibition of p38. Phosphorylation of Akt by TGF-β/Smad3 was not dependent on gene expression or protein synthesis, and immunoprecipitation studies revealed a physical association among p38, Akt, and Smad3 suggesting that activation requires a direct protein-protein interaction. Our findings were confirmed in vivo where overexpression of Smad3 in a rat carotid injury model led to enhancement of p-p38, p-Akt, as well as SMC proliferation. Furthermore, inhibition of p38 in vivo led to decreased Akt phosphorylation and SMC proliferation. In summary, our studies reveal a novel pathway whereby TGF-β/Smad3 stimulates SMC proliferation through p38 and Akt. These findings provide a potential mechanism for the substantial effect of TGF-β on intimal hyperplasia and suggest new targets for chemical or molecular prevention of vascular restenosis.
Antenatal imatinib treatment reduces pulmonary vascular remodeling in a rat model of congenital diaphragmatic hernia
Authors: Chang Ya-Ting , Ringman Uggla Andreas , Österholm Cecilia , Tran Phan-Kiet , Eklöf Ann-Christine , Lengquist Mariette , Hedin Ulf , Tran-Lundmark Karin , Frenckner Björn
Published: March 2012

The pathophysiology of congenital diaphragmatic hernia (CDH) is constituted by pulmonary hypoplasia and pulmonary hypertension (PH). We previously reported successful treatment with imatinib of a patient with CDH. This study examines the effect of antenatal imatinib administration on the pulmonary vasculature in a rat model of CDH. Pregnant rats were given nitrofen to induce CDH. Controls were given olive oil. Half of the CDH fetuses and half of the controls were treated with imatinib antenatally E17-E21, rendering four groups: Control, Control+Imatinib, CDH, and CDH+Imatinib. Lung sections were obtained for morphometry and immunohistochemistry, and protein was purified for Western blot. Effects of nitrofen and imatinib on Ki-67, caspase-3, PDGF-B, and PDGF receptors were analyzed. Imatinib significantly reduced medial wall thickness in pulmonary arteries of rats with CDH. It also normalized lumen area and reduced the proportion of fully muscularized arteries. Imatinib also caused medial thinning in the control group. Cell proliferation was increased in CDH, and this proliferation was significantly reduced by imatinib. PDGF-B and PDGFR-β were upregulated in CDH, and imatinib treatment resulted in a downregulation. PDGFR-α remained unchanged in CDH but was significantly downregulated by imatinib. Antenatal imatinib treatment reduces development of medial wall thickness and restores lumen area in pulmonary arteries in nitrofen-induced CDH. The mechanism is reduced cell proliferation. Imatinib is an interesting candidate for antenatal therapy for PH in CDH, but potential side effects need to be investigated and more specific targeting of PDGF signaling is needed.
Preparation and foaming extrusion behavior of polylactide acid/polybutylene succinate/montmorillonoid nanocomposite
Authors: Ma Pengcheng , Wang Xiangdong , Liu Bengang , Li Ying , Chen Shihong , Zhang Yuxia , Xu Guozhi
Published: March 2012

Polylactic acid (PLA)/polybutylene succinate (PBS) and the PLA/PBS/montmorillonite (MMT) composites were prepared by melt extrusion. The morphology structure, mechanical, thermal, and dynamic rheological properties of the composites were characterized, as well as foaming extrusion behavior of the composites was also studied. The results showed that MMT particles were intercalated into the PLA/PBS matrix forming an ‘intercalation’ structure. The toughness of PLA could be improved by blending with PBS. The comprehensive evaluation of mechanical properties of PLA/PBS was further improved by adding MMT. MMT could play the role of heterogeneous nucleation to improve the crystallization effect of PLA/PBS composite. The melt strength of PLA could be significantly increased by the synergies of MMT and PBS. Meanwhile, MMT could act as a compatibilizer to enhance the interfacial interaction between PLA and PBS. The synergies of PBS and MMT effectively reduced the density of PLA blend foam products, and increased their cell density, uniformity of cell size, and shape distribution.
Scientists Seen by Children
Authors: Ruiz-Mallén Isabel , Escalas Maria Teresa
Published: March 2012

Evidence shows that people in Western societies often have a stereotypical image of science and scientists, but studies have mainly focused on English-speaking countries. This article assesses children’s and adolescents’ perceptions of scientists in Catalonia, Spain. An analysis of the perceived image of scientists was conducted using 236 drawings. Findings suggest that Catalan children perceive scientists as stereotypical and that this image is dominant among boys older than 12 years. To reduce the gap between children’s perceptions and scientists’ reality, more efforts must be addressed from science communication research and science education institutions.
Is Internet Use Associated With Reporting Fewer Problems in Collaboration?
Authors: Duque Ricardo B. , Miller B. Paige , Barriga Omar , Shrum Wesley , Henríquez Guillermo
Published: March 2012

In the developing world, many advocate the benefits of collaboration as the primary driver of research productivity. One of the crucial conditions that support, and help overcome problems in, distributed work is consistent access and use of Internet technologies. But it is argued that the collaborative benefits of Internet technologies are not symmetrically distributed worldwide, perhaps a result of neo-dependency relationships between the South and the North. To evaluate this, in this article, the authors consider the association between “e-mail use and diversity,” “reported problems in web surfing,” and “problems in research collaboration” for a population of scientists outside the mainstream, in the South American nation of Chile. They surveyed 337 scientists over three regions asking them to report on their collaborative behavior, Internet use, and research challenges. While they find that Chileans on the whole report fewer problems compared with other less developed nations studied in this way, they do report problems when reporting more collaborators and when their professional network is geographically heterogeneous. E-mail use, though, has no association with less frequent reports of research challenges, while reporting that “the Internet has made them more connected” and reporting (more intensely) “problems encountered while surfing the web” are significantly associated with reporting more problems in research, when controlling for background, professional activities, institutional and field context, and the number and location of collaborators.
Photographs and stories: ethics, benefits and dilemmas of using participant photography with Black middle-class male youth
Authors: Allen Quaylan
Published: March 2012

Drawing upon research conducted with Black American middle-class youth in a secondary school, this article highlights the use of participant photography with Black male youth. Participant photography is a visual method that places the power of photo documentation in the hands of research subjects, empowering them to document and reflect on social issues and cultural phenomena important to them. This article highlights the significance of the method when exploring the understudied lives of Black middle-class males, ethical considerations of using visual methods with youth populations, as well as the benefits and dilemmas of engaging Black male youth in participant photography. Visual and narrative data produced from the participant photography project are used to highlight the benefits and ethical dilemmas of the method when working with Black male middle-class youth.
An Ion Adsorption Model Related to the Change in the Standard Chemical Potential of Adsorption Reactions
Authors: Wu Xiaofu
Published: March 2012

A simple model is proposed for the prediction of equilibrium ion adsorption in liquid/solid systems. The establishment of the model was based on the assumption that the change in the standard chemical potential of the adsorption system should be zero if ion adsorption taking place spontaneously at a constant temperature is purely a thermodynamic process in which, driven by the electrochemical potentials, the ions move between liquid and solid phases without changing their chemical nature. Experiments have been conducted to test this assumption using the adsorption of Zn2+, Cd2+ and K+ ions from aqueous solutions onto swelling vermiculite, natural zeolite and synthetic zeolite. The results showed that the proposed model fitted the experimental data well. This study provides evidence that, under the conditions employed, ion adsorption reactions are essentially physical processes and the change in the standard chemical potential of the adsorption reaction is negligible.
Carbon Dioxide Capture by Dendrimer-Modified Silica Nanoparticles
Authors: Yu Bing , Cong Hailin , Zhao Xiu Song , Chen Zhaojing
Published: March 2012

Aminosilane- and dendrimer-modified silica nanoparticles were synthesized in the presence of (3-aminopropyl)trimethoxysilane and melamine-based dendrimer, respectively. The surface properties, morphology and carbon dioxide adsorption/desorption performances of the silica nanoparticles before and after surface modification were studied and compared. Severe aggregation of the silica nanoparticles was largely minimized after surface modification. The carbon dioxide adsorption capacity of the dendrimer-modified silica nanoparticles was significantly enhanced in comparison with the unmodified and aminosilane-modified silica nanoparticles because of the large surface area and presence of functional groups exhibiting CO2 affinity in the former.
Dreams, Genius Loci and Structures
Authors: Samyn Philippe
Published: March 2012

Structures and services are profoundly characteristic of the designs of Samyn and Partners in a quest for constructions that tally with the client's dreams and wishes and are in harmony with the genius loci (the special atmosphere of a particular place).

The development of my theory on volume and displacement indicators permanently fuels our structural design work.

Projects that did not come to fruition also foster research and are therefore just as important as those that were actually built.

The approach will thus be illustrated by some projects as well as completed constructions.
The Future Role of Hydro Plant in Maximising the Integration of Wind Generation
Authors: Piekutowski Marian , Halley Andrew , Denholm Stephen
Published: March 2012

This paper describes the changing role of hydro-electric generation in Tasmania in the presence of expanding wind energy developments. Whereas hydro generators have traditionally been dispatched on the premise of satisfying energy requirements, with other power system security functions including voltage control, frequency control, fault current contribution, inertia etc largely satisfied by default, analysis suggests that hydro generators will need to be utilised more deliberately for their ancillary service capabilities if high levels of wind penetration are to be realised in Tasmania. This paper presents a selection of design modifications currently being investigated for existing hydro plant which are aimed at extending certain ancillary service capabilities, while minimising impacts on water storage strategies. Discussions include trade-offs that exist under such operational regimes, as well as the need for revised market arrangements necessary to adequately compensate generators for their role as renewable energy facilitators.
Imbalance Costs of Wind Power for a Hydro Power Producer in Finland
Authors: Holttinen Hannele , Koreneff Göran
Published: March 2012

This paper studies imbalance costs for wind power for different options of managing imbalances from a large producer point of view. In the Nordic electricity markets wind power producers at the markets sell their production based on day-ahead forecasts and pay imbalance fees for prediction errors. Most of the wind power production goes through Balance Responsible Players that have time to adjust the planned production levels or enter trades up to the hour of delivery. In this paper, the imbalance fees for dispersed wind power in Finland for year 2004 data are calculated with four options. The base case leaves all day-ahead forecast errors to balance settlement. Imbalance cost will then be 0.62 €/MWh for dispersed wind power in Finland. The crossover benefit of combining the imbalances of wind with imbalances of load and other production proves to be large, especially if the imbalances can be combined with those of load. Different options for active trade 3 hours before delivery or internal balancing show that it is only cost effective if trading close to spot market prices (at low wind penetration). A rough estimate shows that 400 MW of hydro power could provide internal balancing to cover 83…63% of the forecast errors of wind power, when wind power is 200…400 MW. The market value for this balancing service was 1.3 €/MWh with 2004 prices.
Modelling the Fire Resistance of Prestressed Concrete Floors using Multi-Spring Connection Elements
Authors: Min Jeong-Ki , Dhakal Rajesh , Moss Peter , Buchanan Andrew , Abu Anthony
Published: March 2012

The fire resistance of precast prestressed concrete floor systems is heavily influenced by the end connections and the stiffness of the surrounding structure, both of which must be considered in any analysis. Analysing floor slabs with beam or shell elements whose end nodes share the nodes of supporting beams leads to a major problem for precast prestressed flooring systems where the steel tendons terminate at the end of the flooring units, because the approach of sharing nodes of the supporting beam and floor assumes that these tendons are anchored into the supporting beams. In order to solve this problem, a "multi-spring" connection element has been developed. Experimental data available from previous research work has been used to validate the finite element model. It is concluded that the inclusion of the multi-spring connection results in more accurate predictions of prestressed hollowcore slab behaviour in fire conditions.
Democracia e mobilização social: participação autônoma e instituições políticas na transição brasileira
Authors: Rodrigues Alberto Tosi
Published: March 2012

O artigo propõe uma leitura das mobilizações e desmobilizações políticas da sociedade como a contrapartida dos processos de ampliação e estreitamento dos canais institucionais que regulam a interação dos atores, isto é, como movimentos de "socialização" ou "privatização" do conflito sócio-político. Tomando o caso empírico brasileiro, discute a transição e a "consolidação" democráticas do ponto de vista da permeabilidade do sistema político à participação autônoma da sociedade mobilizada.
El muestreo en investigación cualitativa: principios básicos y algunas controversias
Authors: Martínez-Salgado Carolina
Published: March 2012

En este trabajo se presentan los fundamentos de la elección de los participantes en una investigación cualitativa, en contraste con los que rigen al muestreo probabilístico en la investigación epidemiológica. Se proponen los conceptos de generalizabilidad nomotética e ideográfica, y los de transferibilidad y reflexividad, para una mejor comprensión de las diferencias. Se mencionan los fundamentos de los principales tipos de muestreo que suelen utilizarse en investigación cualitativa, el significado del concepto de saturación y algunos de sus cuestionamientos. Por último, se plantean algunas reflexiones en torno a las controversias suscitadas en los últimos años sobre las diversas perspectivas paradigmáticas desde las cuales se puede efectuar hoy día la investigación cualitativa, sus posibilidades de combinación con la investigación epidemiológica, y algunas implicaciones para el estudio de los problemas de salud.
Trabalho de campo, narrativa e produção de conhecimento na pesquisa etnográfica contemporânea: subsídios ao campo da saúde
Authors: Trad Leny Alves Bomfim
Published: March 2012

Neste artigo desenvolvo um exercício de reflexão em torno das peculiaridades da pesquisa etnográfica contemporânea, assinalando alguns desafios inerentes a este processo. A discussão se centrará, especialmente, nos seguintes aspectos: os limites impostos pela notória abreviação do tempo de imersão no campo; os desafios na aprendizagem do trabalho etnográfico, seja nos processos de observação ou interação no campo, seja na tarefa de produção textual; questões de caráter epistemológico e ético que merecem uma atenção especial no por parte dos praticantes da abordagem etnográfica e da comunidade científica em geral. Considero, especialmente, oportuno promover o debate em torno do método etnográfico, abordando suas peculiaridades, complexidade operacional e potencialidades enquanto ferramenta de produção de conhecimento, na esfera da saúde/ saúde coletiva, tendo em vista o incremento notável desta abordagem neste campo.
O uso de tomografia computadorizada nas internações por Acidente Vascular Cerebral no Sistema Único de Saúde no Brasil
Authors: Rolim Cristina Lúcia Rocha Cubas , Martins Monica
Published: March 2012

O Acidente Vascular Cerebral é um dos principais motivos de internação no Sistema Único de Saúde. O exame de tomografia computadoriza tem sido indicado como o principal método diagnóstico de imagem para a definição do tratamento do Acidente Vascular Cerebral. O objetivo desse artigo é avaliar a utilização de exames de tomografia computadorizada em internações por Acidente Vascular Cerebral com base nas informações do Sistema de Informação Hospitalar do Sistema Único de Saúde. O universo de estudo incluiu as internações de pacientes adultos ocorridas no Brasil e financiadas pelo Sistema Único de Saúde entre abril de 2006 e dezembro de 2007. A análise dos dados foi descritiva para o conjunto de casos de Acidente Vascular Cerebral e para cada subgrupo separadamente. Das 328.087 internações por Acidente Vascular Cerebral, observou-se que em 73,5% o exame não foi realizado. Nas internações que realizaram tomografia computadorizada, 22,3% tiveram acesso a um exame e somente 4,2% a dois exames. Além de subutilizado, o exame de tomografia computadorizada, quando realizado, não trouxe melhora na codificação adequada do subgrupo da doença.
Specificity of Antimicrobial Peptide LL‐37 to Neutralize Periodontopathogenic Lipopolysaccharide Activity in Human Oral Fibroblasts
Authors: Suphasiriroj Wiroj , Mikami Masato , Shimomura Hiromi , Sato Soh
Published: March 2012

Background: The antimicrobial peptide LL‐37 is known to have a potent lipopolysaccharide (LPS)‐neutralizing activity in various cell types. Because of observed heterogeneity within periodontopathogenic LPS, the authors hypothesized that LL‐37 had specificity to neutralize such LPS activity. The present study, therefore, aims to investigate the LPS‐neutralizing activity of LL‐37 to various periodontopathogenic LPS in interleukin‐8 (IL‐8) production after challenging them in human oral fibroblasts.

Methods: Human periodontal ligament fibroblasts (PDLF) and gingival fibroblasts (GF) were cultured from biopsies of periodontal ligament and gingival tissues. After cell confluence in 24‐well plates, LPS (10 μg/mL) from Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans were added with or without LL‐37 (10 μg/mL). After 18 hours, the supernatant was collected and analyzed in IL‐8 production by enzyme‐linked immunosorbent assay.

Results: All periodontopathogenic LPS statistically significantly induced IL‐8 production in both PDLF and GF (P <0.01). After neutralization with LL‐37, both PDLF and GF showed a statistically significant reduction in IL‐8 production compared with LPS‐treated groups without LL‐37 (P <0.01), and the percentage of reduction in IL‐8 production in PDLF appeared to be higher than in GF. In addition, the percentage of reduction in IL‐8 production varied considerably according to each periodontopathogenic LPS.

Conclusions: The antimicrobial peptide LL‐37 had an ability to suppress periodontopathogenic LPS‐induced IL‐8 production in both PDLF and GF. Its LPS‐neutralizing activity revealed specificity to periodontopathogenic LPS and seemed to be dependent on the heterogeneity within LPS between different genera.
Potential role of noncommercial swine populations in the epidemiology and control of porcine reproductive and respiratory syndrome virus
Authors: Wayne Spencer R. , Morrison Robert B. , Odland Carissa A. , Davies Peter R.
Published: March 2012

Objective—To assess the role of noncommercial pigs in the epidemiology of porcine reproductive and respiratory syndrome (PRRS) virus.

Design—Seroepidemiologic study and survey study.

Animals—661 pigs from which blood samples were collected at slaughter and 32 pigs from which blood samples were collected longitudinally.

Procedures—Spatial databases of commercial farms and 4-H participation were evaluated by use of commercial geographic information systems software. Information on disease knowledge and management methods of 4-H participants was obtained by mail survey and personal interview. Serum samples for antibody testing by PRRS ELISA were obtained from pigs at slaughter or at county fairs and on farms.

Results—Participation in 4-H swine programs was geographically associated with commercial swine production in Minnesota, and 39% of 4-H participants reared pigs at locations with commercial pigs. High seroprevalence at fairs (49%; range, 29% to 76%) and seroconversion after fairs indicated that PRRS virus exposure was common in pigs shown by 4-H participants and that transmission could occur at fairs.

Conclusions and Clinical Relevance—The small swine population shown by 4-H members (estimated 12,000 pigs) relative to the population of commercial swine in Minnesota (estimated 6.5 million pigs) suggested the former overall was likely of minor importance to PRRS virus epidemiology at present. However, the relative frailty of knowledge of biosecurity practices, evidence that PRRS virus exposure was frequent, common intentions to show pigs at multiple events, and often close interactions with commercial herds suggested that the 4-H community should be involved in regional efforts to control PRRS.
The Bethesda System thyroid diagnostic categories in the African-American population in conjunction with surgical pathology follow-up
Authors: Archuletta Pamela Anne , Gidwani Raja , Husain Mujtaba , Johnson Teresa , Shidham Vinod , Alzohaili Opada , Bandyopadhyay Sudeshna , Feng Jining , Shi Dongping , Geng Lili , Tranchida Paul , Giorgadze Tamar
Published: March 2012

Background:

It has been reported that African-Americans (AA) have a higher prevalence of overall malignancy compared to Caucasians, in the United States, yet the incidence of thyroid malignancy is half. The aim of this study is to assess the rate of malignant versus benign thyroid disease in AA from an urban-based hospital with an academic setting. Our study analyzed the AA population with respect to fine needle aspiration (FNA) of thyroid lesions, in correlation with final surgical pathology. This is the first study of its kind to our knowledge.

Design:

We retrospectively reviewed thyroid FNA cytology between January 2005 and February 2011. Consecutive FNA specimens with corresponding follow-up surgical pathology were included. The patients were categorized as African- American (AA) and Non-African-American (NAA), which included Caucasians (C), Hispanics (H), and Others (O). The FNA results were classified using the latest edition of The Bethesda System for Reporting Thyroid Cytopathology (TBS-Thy) and the follow-up surgical pathology was used for the final categorization.

Results:

We studied 258 cases: 144 AA (56%) and 114 NAA [43 C (17%), 3 H (1%), and 68 O (28%)]. The average age for AA was 51 years (range 20 – 88) and for NAA was 53 years (range 25 – 86). There were more females than males in the AA versus the NAA group (85 vs. 75%). The incidence of thyroid lesions in the FNA specimens was similar between these two populations. The distribution of benign versus malignant diagnosis on follow-up surgical pathology was examined across TBS-Thy class.

Conclusion:

Our data suggest that distribution of benign versus malignant lesions in the thyroid FNA of AA versus NAA, with follow-up surgical pathology, is comparable for TBS-Thy classes, non-diagnostic (I), benign (II), suspicious for malignancy (V), and malignant (VI) in AA versus NAA.
A general and efficient cantilever functionalization technique for AFM molecular recognition studies
Authors: Bowers Carleen M. , Carlson David A. , Shestopalov Alexander A. , Clark Robert L. , Toone Eric J.
Published: March 2012

Atomic force microscopy (AFM) is a versatile technique for the investigation of noncovalent molecular associations between ligand–substrate pairs. Surface modification of silicon nitride AFM cantilevers is most commonly achieved using organic trialkoxysilanes. However, susceptibility of the SiO bond to hydrolysis and formation of polymeric aggregates diminishes attractiveness of this method for AFM studies. Attachment techniques that facilitate immobilization of a wide variety of organic and biological molecules via the stable SiC bond on silicon nitride cantilevers would be of great value to the field of molecular recognition force spectroscopy. Here, we report (1) the formation of stable, highly oriented monolayers on the tip of silicon nitride cantilevers and (2) demonstrate their utility in the investigation of noncovalent protein–ligand interactions using molecular recognition force spectroscopy. The monolayers are formed through hydrosilylation of hydrogen‐terminated silicon nitride AFM probes using a protected α‐amino‐ω‐alkene. This approach facilitates the subsequent conjugation of biomolecules. The resulting biomolecules are bound to the tip by a strong SiC bond, completely uniform with regard to both epitope density and substrate orientation, and highly suitable for force microscopy studies. We show that this attachment technique can be used to measure the unbinding profiles of tip‐immobilized lactose and surface‐immobilized galectin‐3. Overall, the proposed technique is general, operationally simple, and can be expanded to anchor a wide variety of epitopes to a silicon nitride cantilever using a stable SiC bond. © 2012 Wiley Periodicals, Inc. Biopolymers 97: 761–765, 2012.
Microwave‐assisted alkylation of diethyl ethoxycarbonylmethylphosphonate under solventless conditions
Authors: Grün Alajos , Blastik Zsófia , Drahos László , Keglevich György
Published: March 2012

The reaction of diethyl ethoxycarbonylmethylphosphonate with a series of alkyl halides, under microwave (MW) and solventless conditions at 120°C, in the presence of Cs2CO3 and in the absence of a phase transfer catalyst afforded the corresponding monoalkylated products in yields of >70%. The thermal variant carried out in boiling acetonitrile was slow and led to incomplete conversions. In the MW method, the phase transfer catalyst is substituted by MW irradiation and there is no need for a solvent. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:241–246, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21009
Comparative risk assessment of carcinogens in alcoholic beverages using the margin of exposure approach
Authors: Lachenmeier Dirk W. , Przybylski Maria C. , Rehm Jürgen
Published: March 2012

Alcoholic beverages have been classified as carcinogenic to humans. As alcoholic beverages are multicomponent mixtures containing several carcinogenic compounds, a quantitative approach is necessary to compare the risks. Fifteen known and suspected human carcinogens (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, lead, 4‐methylimidazole, N‐nitrosodimethylamine, ochratoxin A and safrole) occurring in alcoholic beverages were identified based on monograph reviews by the International Agency for Research on Cancer. The margin of exposure (MOE) approach was used for comparative risk assessment. MOE compares a toxicological threshold with the exposure. MOEs above 10,000 are judged as low priority for risk management action. MOEs were calculated for different drinking scenarios (low risk and heavy drinking) and different levels of contamination for four beverage groups (beer, wine, spirits and unrecorded alcohol). The lowest MOEs were found for ethanol (3.1 for low risk and 0.8 for heavy drinking). Inorganic lead and arsenic have average MOEs between 10 and 300, followed by acetaldehyde, cadmium and ethyl carbamate between 1,000 and 10,000. All other compounds had average MOEs above 10,000 independent of beverage type. Ethanol was identified as the most important carcinogen in alcoholic beverages, with clear dose response. Some other compounds (lead, arsenic, ethyl carbamate, acetaldehyde) may pose risks below thresholds normally tolerated for food contaminants, but from a cost‐effectiveness point of view, the focus should be on reducing alcohol consumption in general rather than on mitigative measures for some contaminants that contribute only to a limited extent (if at all) to the total health risk.
Subchronic microcystin‐lr exposure increased hepatic apoptosis and induced compensatory mechanisms in mice
Authors: Lezcano Noelia , Sedán Daniela , Lucotti Ignacio , Giannuzzi Leda , Vittone Leticia , Andrinolo Darío , Mundiña‐Weilenmann Cecilia
Published: March 2012

Acute lethal cytotoxicity of microcystin‐LR (MC‐LR), a toxin produced by fresh‐water cyanobacteria, has been attributed to protein phosphatases type 1 and type 2A (PP1/PP2A) inhibition and reactive oxygen species (ROS) generation. However, the effects and molecular mechanisms of prolonged, sublethal MC‐LR exposure are less known. We studied mice intraperitonealy injected with saline or 25 μg MC‐LR/kg for 28 days (every 2 days). MC‐LR induced apoptosis in liver and not in kidneys or heart of treated animals. Liver also showed decreased α‐tubulin levels (45.56% ± 7.65% of controls) and activation of p38‐MAPK and CaMKII pathways (137.93% ± 11.64% and 419.35% ± 67.83% of the control group, respectively). PP1/PP2A activity decreased from 1.82 ± 0.23 (controls) to 0.91 ± 0.98 mU/mg (MC‐LR–treated mice); however, no difference in total Ser/Thr phosphatase activity was found between both the groups. The results demonstrated that apoptosis and cytoskeleton disruption contributed to the hepatic cytotoxic effects of subchronic MC‐LR administration. These effects occurred in association with sustained activation of signaling cascades and development of compensatory mechanisms to maintain total Ser/Thr phosphatase activity. © 2012 Wiley Periodicals, Inc. J Biochem Mol Toxicol 26:131–138, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.20419
Tetramethylguanidinium‐polyallylamine (Tmg‐PA): A new class of nonviral vector for efficient gene transfection
Authors: Mahato Manohar , Rana Gaurav , Kumar Pradeep , Sharma Ashwani Kumar
Published: March 2012

Highly toxic polyallylamine (PA) was reacted with a varying amount of a novel linker, 6‐(N,N,N′,N′‐tetramethylguanidinium chloride) hexanoic acid (Tmg‐HA), to prepare a series of tetramethylguanidinium‐PA (Tmg‐PA) polymers, which were used as vectors for gene transfection. The extent of attachment of the linker, Tmg‐HA, to the PA backbone was determined by 2,4,6‐trinitrobenzene sulfonic acid assay. The modified polymers (Tmg‐PAs), when complexed with pDNA, exhibited good condensation ability. The nanoparticles, so formed, were characterized by their size and zeta potential and were subsequently evaluated for their toxicity and transfection ability on various mammalian cells, viz., HeLa, CHO, and HEK 293 cells. Mobility shift assay revealed that on increasing the percent substitution of Tmg‐HA onto PA (from Tmg‐PA1 to Tmg‐PA6), relatively higher amounts of modified polymers were required to retard the mobility of a fixed amount of DNA. Besides, Tmg‐PA polymers provided sufficient protection (ca. 84–88%) to bound DNA against nucleases and one of the formulations, Tmg‐PA2 (ca. 15% substitution) displayed the highest transfection efficiency outcompeting the commercial transfection reagent, Lipofectamine™ with minimal cytotoxicity. More impressively, the transfection efficiency increased despite recording a decrease in the buffering capacity of the grafted polymers suggesting that buffering capacity is not the sole parameter in determining the gene delivery efficiency of a vector system. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Vacancy spatial distribution causes different magnetism in graphene
Authors: Antonov Vladislav , Borisova Dobrina , Proykova Ana
Published: March 2012

Recent reliable experiments have reported magnetism in defective graphene while the perfect one is nonmagnetic. In this work, we study the role of the vacancy concentration and spatial distribution on the orientation and magnitude of the magnetic moments induced by the defects with the help of the Quantum Espresso code, which is a plane‐wave implementation of the density functional theory. In the case of more than one vacancy per supercell, interaction between the total magnetic moments at each defective site occurs. The interaction is ferromagnetic for vacancies in the same sublattices and it is antiferromagnetic for the case of different sublattices. © 2012 Wiley Periodicals, Inc.
Compressible inviscid instability of rapidly expanding spherical material interfaces
Authors: Mankbadi Mina R. , Balachandar S.
Published: March 2012

A high-order weighted essentially non-oscillatory scheme is employed to investigate the stability of a rapidly expanding material interface produced by a spherical shock tube. The flow structure is characterized by a forward moving primary shock, a backward moving secondary shock, and a spherical contact interface in-between. We consider herein the linear inviscid regime and focus on the development of the three-dimensional perturbations around the contact interface by solving a one-dimensional system of partial differential equations. Numerical simulations are performed to illustrate the effects of the contact interface's density discontinuity on the growth of the disturbances for various spherical wave numbers. In a spherical shock tube the instability is influenced by various mechanisms which include classical Rayleigh-Taylor (RT) effects, Bell-Plesset or geometry/curvature effects, the effects of impulsively accelerating the interface, and compressibility effects. Henceforth, the present instability will be referred to as non-classical RT instability to distinguish it from classical RT instability. For an extended intermediate time period, it can be shown that the small disturbances grow exponentially as in the classical RT instability. During this stage, the exponential growth rate increases with the spherical wave number, until it saturates for very large wave numbers due to the finite thickness limitation of the numerical representation of the contact interface. The results compare favorably with previous theoretical models; but indicate that in addition to compressibility, the space-time evolution of the contact interface's thickness plays a significant role. A parametric study is performed that varies the pressure and density ratios of the initial spherical container. The characteristics of the contact interface and the applicability of various instability theories is investigated for these regimes. Furthermore, varying the pressure and density ratios aids in understanding significance of compressibility effects on the instability at different operating conditions.
Wall-locking of kink modes in a line-tied screw pinch with a rotating wall
Authors: Paz-Soldan C. , Brookhart M. I. , Hegna C. C. , Forest C. B.
Published: March 2012

The effect of rotating conducting walls on mode-locking is studied in a line-tied, linear screw pinch experiment and then compared to a torque balance model which has been extended to include differential wall rotation. Wall rotation is predicted to asymmetrically affect the mode-unlocking threshold, with fast rotation eliminating the locking bifurcation. Static error fields are observed to lock the resistive wall mode (RWM) variant of the current driven kink instability by modifying the electromagnetic torque. Using locked modes, the stabilizing effect of wall rotation on the RWM is experimentally demonstrated by illustrating a reduction of the RWM growth rate and an extension of the RWM-stable operation window.
Fusion reactions from >150 keV ions in a dense plasma focus plasmoid
Authors: Lerner Eric J. , Murali S. Krupakar , Shannon Derek , Blake Aaron M. , Roessel Fred Van
Published: March 2012

Using a dense plasma focus device with a 50 kJ capacitor charge, we have observed fusion reactions from deuterium ions with record energies of >150 keV, which are confined for durations of 7–30 ns in the cores of plasmoids with typical radii of 300–500 μm and densities ∼3 × 1019 cm−3. We have for the first time simultaneously imaged the plasmoid at high (30 μm) resolution and measured trapped ion energy and neutron anisotropy. The isotropy of the neutron emission as well as other observations confirms that the observed neutrons per pulse of up to 1.5 × 1011 are produced mainly by confined ions, not an unconfined beam. The conditions achieved are of interest for aneutronic fusion, such as with pB11 fuel.