Current-induced cooling phenomenon in a two-dimensional electron gas under a magnetic field

We investigate the spatial distribution of temperature induced by a dc current in a two-dimensional electron gas (2DEG) subjected to a perpendicular magnetic field. We numerically calculate the distributions of the electrostatic potential phi and the temperature T in a 2DEG enclosed in a square area surrounded by insulated-adiabatic (top and bottom) and isopotential-isothermal (left and right) boundaries (with phi_{left} < phi_{right} and T_{left} =T_{right}), using a pair of nonlinear Poisson equations (for phi and T) that fully take into account thermoelectric and thermomagnetic phenomena, including the Hall, Nernst, Ettingshausen, and Righi-Leduc effects. We find that, in the vicinity of the left-bottom corner, the temperature becomes lower than the fixed boundary temperature, contrary to the naive expectation that the temperature is raised by the prevalent Joule heating effect. The cooling is attributed to the Ettingshausen effect at the bottom adiabatic boundary, which pumps up the heat away from the bottom boundary. In order to keep the adiabatic condition, downward temperature gradient, hence the cooled area, is developed near the boundary, with the resulting thermal diffusion compensating the upward heat current due to the Ettingshausen effect.Comment: 25 pages, 7 figure

ゲンパツ フメイ ガン ニオケル PET/CT ケンサ ノ ユウヨウセイ ニツイテ

We reported the utility of１８F-FDG-PET/CT examination for patients with cancer of unknownprimary origin. Twenty six patients（13 men, 13 women, aged 27-91 years, mean 71）were examined.The indication for PET/CT examination was tumor maker elevation（14 patients）, suspectedmetastatic tumor（14）and metastasis diagnosed histopathologically（3）. Patients weretold not to eat for at least four hours and a PET/CT image was obtained one hour after theadministration of 3.7MBq/kg FDG. From April to August 2006, 33 patients diagnosed with a cancerof unknown primary origin were referred to our hospital for PET/CT examination from anoutside institution. Twenty six patients could be investigated for outcomes. Seventeen patientsshowed an abnormal accumulation, with 14 of the 17 having their primary regions detected histopathologicallyor clinically. For one patient, the abnormal accumulation could not be determined toshow the origin. For 2 patients, it was difficult to diagnose if these abnormal accumulationsshowed the primary region or not, but CT examinations were helpful for a diagnosis. Seven of the9 patients who showed no abnormal accumulation were treated conservatively and the primaryregion for their cancer could not be detected during the follow up study. In 21 of 26 patients, theseresults were useful to select an appropriate therapy to be applied or a relevant examination. Weconsidered PET/CT examination, where it is possible to scan the whole body at one time, was veryuseful to get both morphologic and metabolic information. PET/CT examination showed a highersensitivity for detecting abnormal lesions than other imaging modalities

Lineage Analysis of Circulating Trypanosoma cruzi Parasites and Their Association with Clinical Forms of Chagas Disease in Bolivia

Around 30–50% of Trypanosoma cruzi infections in Latin America cause chronic Chagas disease 10–30 years after the primary infection due to lack of effective treatment. The major clinical complications associated with chronic Chagas disease are cardiac myositis (leading to cardiac failure), and autonomous neuroplexus degeneration of the digestive tract that can cause megacolon or megaesophagus. Therefore, there are three major clinical forms of Chagas disease; cardiac, digestive and indeterminate (asymptomatic). The parasites, which can infect humans as well as other mammals, are transmitted by species of triatomines commonly found in the Americas. The parasite is divided in at least six discrete typing units: TcI, TcIIa–e. In humans, the TcI is mainly observed in Central America and northern parts of South America while the TcIIb/d/e is confined mainly to the southern cone of Latin America. We determined which DTU were prevalent in chronic patients in Bolivia, where the three clinical forms and several DTUs of the parasites are present, in order to determine whether there was a link between a particular parasite DTU and a particular clinical outcome. We found a vast majority of TcIId but its kDNA polymorphism showed no association with any of the clinical manifestations of chronic Chagas

Tamponamento intrauterino induzido por vácuo para hemorragia pós-parto: uma revisão sistemática

A hemorragia pós-parto (HPP) é uma complicação grave e uma das principais causas de mortalidade materna global, respondendo por aproximadamente 25% de todos os óbitos maternos. A busca por intervenções eficazes e seguras é crítica para melhorar os desfechos maternos. O tamponamento intrauterino induzido por vácuo (VHD) surgiu como uma abordagem promissora, oferecendo potencial para rápido controle do sangramento e redução da necessidade de procedimentos invasivos. Nesse sentido, o presente estudo tem como objetivo analisar a eficácia, segurança e aplicabilidade na prática clínica moderna. Foi realizada uma revisão sistemática da literatura de 2016 a 2024 nas bases de dados PubMed (Medline), Cochrane Library e SciELO. A seleção dos estudos foi baseada em critérios de inclusão e exclusão rigorosos, focando na eficácia, segurança e aplicabilidade do VHD para tratamento da HPP. Três estudos chave foram analisados, com pacientes submetidos ao tratamento com VHD para HPP. Os resultados demonstraram uma taxa de sucesso no tratamento variando de 73% a 94%, com um controle do sangramento alcançado em uma média de 3 minutos. Foi observada uma redução significativa na necessidade de transfusões maciças de sangue e na perda de sangue estimada quando comparado com o tamponamento com balão uterino. Eventos adversos foram relatados, mas todos resolveram-se sem sequelas graves. O tamponamento intrauterino induzido por vácuo apresenta-se como uma opção promissora no tratamento da hemorragia pós-parto, com resultados consistentes indicando eficácia no controle do sangramento e redução na necessidade de transfusões sanguíneas. Embora os resultados sejam encorajadores, mais estudos são necessários para confirmar essas descobertas e explorar plenamente o potencial do VHD na prática clínica. O VHD emerge como uma alternativa eficaz e segura, com potencial para melhorar significativamente os desfechos maternos e reduzir a morbimortalidade associada à HPP

Linking Probabilities of Self-Avoiding Polygons(Knots and soft-matter physics: Topology of polymers and related topics in physics, mathematics and biology)

この論文は国立情報学研究所の電子図書館事業により電子化されました。本研究では,環状高分子の溶液やネットワークの性質に深く関係する絡み合い確率を数値的に評価して考察した。絡み合い確率P_L(r)は,2つの環状高分子を重心間距離rだけ離して置いた場合に,それらがリンク・タイプLのトポロジーを持って絡み合う確率である。また,環状鎖が非自明な絡み目をつくる確率をP_(r)と表す。我々は,環状鎖の長さや排除体積を変えてシミュレーションを行い,P_L(r)およびP_(r)の評価を行った。その結果,これらは距離の関数としては次の関数型:P_=exp(-αr^ν)-Cexp(-βr^μ)で表されることが分かった。ここでα,ν,C,β,μは適合変数である。上記の関数はLによらず一般的に成り立つ。さらに,排除体積が極限的に大きい場合を除いて,上式が計算結果を良く再現することがχ^2値のからも裏付けられた。We have numerically investigated the probability P_L(r) for a pair of self-avoiding random polygons (SAPs) being link L such that each of them have the trivial knot type and they have no overlaps among the segments where they are placed with a distance r between the centers of mass. We call it the linking probability of link L. We propose the following fitting formula: P_L(r)=exp(-αr^ν)-C exp(-βr^μ), where α, ν, C, ,β and μ are parameters. For example, P_(r) denotes the probability of the trivial link. We apply the formula also to the data of P_(r), where it is given by P_(r)=1-P_(r). With respect to the χ^2 values, the formula gives good fitting curves to the values of P_(r) versus r obtained by simulation for r_d&le;0.20. In the simulation we generate SAPs consisting of N spherical segments of radius r_d, where the bond length, i.e the distance between adjacent segments, is fixed to 1. We have numerically obtained P_(r) for the cases of N=32, 64, 128 and 256 for r_d= 0.00, 0.05, …, 0.30

Análise do transcriptoma da glândula venenífera de Rhinocerophis alternatus (Bothrops alternatus): identificação de metaloproteases e desintegrinas

The desintegrinas are cys-rich polypeptides without enzymatic activity, some found in snake venoms with an adhesive motif to integrin, unleashing distinct responses. Several research groups have been studying snake venom disintegrins with focus in pharmacological applications in tumor progression and proliferation, angiogenesis, blood clotting, and osteoporosis. This work shows the results of the construction of cDNA library of Rhinocerophis alternatus venom gland, cloning and expression of ALT-C, a disintegrina-like protein, in bacterial system. The library was comprised of 812 sequences that were classified into: (i) coding for hypothetical protein or mismatched in databases (unknown) corresponding to 20.94%; (ii) transcripts for cellular process 17.86%; and (iii) transcripts coding for toxic protein with 61.21%. Among toxic proteins the SVMPs were the most abundant transcripts 58.59%. Other toxic transcripts were C-type lectins (15.56%), bradykinin potentiating peptides (11.8%), serineproteases (5.18%), cys-rich secretory proteins (2.28%), vascular endothelial growth factors (2.28%), L-amino acid oxidases (1.86%) and phospholipases A2 (1.45%). The percentages correspond to this snake venom effects, low enzymatic activity and hemorrhagic and clotting activity as main action, derived from the SVMPs, C-type lectin and serineproteases. One of the SVMPs contigs were chosen based on the similarity with ALT-C, the defined sequence was called ALT-Ch (ALT-C homologue) since there has 4 conservative substitutions compared to the previously determined sequence. The ALT-C-h sequence was used in PCR to inclusion the restriction site for BamHI and EcoRI, cloned in pGEX4T-1 and transformed into E. coli AD494 (DE3) for expression. The cell culture was grown until the log fase and induced with IPTG for 3 hours, the expressed protein's identity was confirmed by Western Blotting using Polyclonal antibody Anti-ALT-C. The construction of the R. alternatus venom gland cDNA library provides a source of interesting active biomolecules, such as desintegrinas, to pharmacological applications in pathologies involving integrins like angiogenesis, tumor progression and metastasis.Financiadora de Estudos e ProjetosAs desintegrinas são polipeptídeos sem atividade enzimática, ricos em cisteína, geralmente encontrados no veneno de serpentes, possuidoras de um motivo adesivo reconhecedor de integrinas antagonizando ou agonizando a atividade das mesmas. Diversos grupos de pesquisa vêm estudando desintegrinas de venenos de serpentes com o foco em aplicação farmacológica nos processos de progressão e proliferação tumoral, angiogênese, coagulação sanguínea, e osteoporose. Este trabalho apresenta os resultados da construção da biblioteca de cDNA da glândula venenífera de Rinocerophis alternatus e a clonagem e expressão da ALT-C, uma tipo desintegrina, em sistema bacteriano. A biblioteca foi composta por 812 sequências que foram classificadas em: (i) codificantes para proteínas hipotéticas ou sem equivalência nos bancos de dados (unknown) correspondendo a 20,94%; (ii) transcritos para produtos celulares 17,86%; e (iii) transcritos codificantes para proteínas tóxicas 61,21%. Dentre as proteínas tóxicas as SVMPs foram os transcritos mais abundantes com 58,59% dos compostos tóxicos do tecido. Os demais transcritos tóxicos encontrados foram as lectinas do tipo-C (15,56%), peptídeos potenciadores de bradicinina (11,8%), serinoproteases (5,18%), proteínas secretórias ricas em cisteína (2,28%), fatores de crescimento endotelial vascular (2,28%), L-aminoácido oxidases (1,86%) e fosfolipases A2 (1,45%). As percentagens encontradas correspondem aos efeitos do veneno dessa serpente, que possui baixa atividade enzimática e predominate ação hemorrágica e de alteração na coagulação sanguínea derivada da ação das SVMPs, lectinas do tipo-C e serinoproteases. Um dos contigs para SVMPs foi eleito pela similaridade com a ALT-C. A sequência determinada por esse contig foi denominada ALT-C-h (homóloga da ALT-C) por apresentar 4 substituições conservativas da sequência determinada anteriormente. A sequência foi utilizada em PCR para inclusão de sítio de restrição para BamHI e EcoRI, clonado em pGEX4T-1 e transformados em E. coli AD494(DE3) para ensaios de expressão. O cultivo foi crescido até a fase log e a indução expressão realizada com IPTG por 3 horas, a identidade da proteína expressa foi confirmada por western blotting utilizando anticorpo policlonal anti-ALT-C. A construção da biblioteca de cDNA da glândula venenífera de R. alternatus fornece uma fonte de estudo interessante de biomoléculas ativas nos venenos como, por exemplo, as desintegrinas visando aplicações farmacológicas para patologias envolvendo integrinas como angiogênese, progressão e metástase tumoral