An all silicon quantum computer

A solid-state implementation of a quantum computer composed entirely of silicon is proposed. Qubits are Si-29 nuclear spins arranged as chains in a Si-28 (spin-0) matrix with Larmor frequencies separated by a large magnetic field gradient. No impurity dopants or electrical contacts are needed. Initialization is accomplished by optical pumping, algorithmic cooling, and pseudo-pure state techniques. Magnetic resonance force microscopy is used for readout. This proposal takes advantage of many of the successful aspects of solution NMR quantum computation, including ensemble measurement, RF control, and long decoherence times, but it allows for more qubits and improved initialization.Comment: ReVTeX 4, 5 pages, 2 figure

On the analysis of sedimentation velocity in the study of protein complexes

Sedimentation velocity analytical ultracentrifugation has experienced a significant transformation, precipitated by the possibility of efficiently fitting Lamm equation solutions to the experimental data. The precision of this approach depends on the ability to account for the imperfections of the experiment, both regarding the sample and the instrument. In the present work, we explore in more detail the relationship between the sedimentation process, its detection, and the model used in the mathematical data analysis. We focus on configurations that produce steep and fast-moving sedimentation boundaries, such as frequently encountered when studying large multi-protein complexes. First, as a computational tool facilitating the analysis of heterogeneous samples, we introduce the strategy of partial boundary modeling. It can simplify the modeling by restricting the direct boundary analysis to species with sedimentation coefficients in a predefined range. Next, we examine factors related to the experimental detection, including the magnitude of optical aberrations generated by out-of-focus solution columns at high protein concentrations, the relationship between the experimentally recorded signature of the meniscus and the meniscus parameter in the data analysis, and the consequences of the limited radial and temporal resolution of the absorbance optical scanning system. Surprisingly, we find that large errors can be caused by the finite scanning speed of the commercial absorbance optics, exceeding the statistical errors in the measured sedimentation coefficients by more than an order of magnitude. We describe how these effects can be computationally accounted for in SEDFIT and SEDPHAT

Важливе історико-географічне дослідження

Рец. на кн. Темушева В.Н. "Гомельская земля в конце XV первой половине XVI в. Территориальные трансформации в пограничном регионе". — М.: "Квадрига", 2009. — 190 с.Review of the book: Temushev V.N. "Gomel Land in the Late 15th — the 1st half of the 16th Centuries. Territorial Transformations in the Frontier Area". — Moscow: "Kvadriga", 2009. — 190 p

The FANCM:p.Arg658* truncating variant is associated with risk of triple-negative breast cancer.

Breast cancer is a common disease partially caused by genetic risk factors. Germline pathogenic variants in DNA repair genes BRCA1, BRCA2, PALB2, ATM, and CHEK2 are associated with breast cancer risk. FANCM, which encodes for a DNA translocase, has been proposed as a breast cancer predisposition gene, with greater effects for the ER-negative and triple-negative breast cancer (TNBC) subtypes. We tested the three recurrent protein-truncating variants FANCM:p.Arg658*, p.Gln1701*, and p.Arg1931* for association with breast cancer risk in 67,112 cases, 53,766 controls, and 26,662 carriers of pathogenic variants of BRCA1 or BRCA2. These three variants were also studied functionally by measuring survival and chromosome fragility in FANCM -/- patient-derived immortalized fibroblasts treated with diepoxybutane or olaparib. We observed that FANCM:p.Arg658* was associated with increased risk of ER-negative disease and TNBC (OR = 2.44, P = 0.034 and OR = 3.79; P = 0.009, respectively). In a country-restricted analysis, we confirmed the associations detected for FANCM:p.Arg658* and found that also FANCM:p.Arg1931* was associated with ER-negative breast cancer risk (OR = 1.96; P = 0.006). The functional results indicated that all three variants were deleterious affecting cell survival and chromosome stability with FANCM:p.Arg658* causing more severe phenotypes. In conclusion, we confirmed that the two rare FANCM deleterious variants p.Arg658* and p.Arg1931* are risk factors for ER-negative and TNBC subtypes. Overall our data suggest that the effect of truncating variants on breast cancer risk may depend on their position in the gene. Cell sensitivity to olaparib exposure, identifies a possible therapeutic option to treat FANCM-associated tumors

Disruption of Nrf2, a Key Inducer of Antioxidant Defenses, Attenuates ApoE-Mediated Atherosclerosis in Mice

Background: Oxidative stress and inflammation are two critical factors that drive the formation of plaques in atherosclerosis. Nrf2 is a redox-sensitive transcription factor that upregulates a battery of antioxidative genes and cytoprotective enzymes that constitute the cellular response to oxidative stress. Our previous studies have shown that disruption of Nrf2 in mice (Nrf2-/-) causes increased susceptibility to pulmonary emphysema, asthma and sepsis due to increased oxidative stress and inflammation. Here we have tested the hypothesis that disruption of Nrf2 in mice causes increased atherosclerosis. Principal Findings: To investigate the role of Nrf2 in the development of atherosclerosis, we crossed Nrf2-/- mice with apoliporotein E-deficient (ApoE-/- mice. ApoE-/- and ApoE-/- Nrf2-/- mice were fed an atherogenic diet for 20 weeks, and plaque area was assessed in the aortas. Surprisingly, ApoE-/- Nrf2-/- mice exhibited significantly smaller plaque area than ApoE-/- controls (11.5% vs 29.5%). This decrease in plaque area observed in ApoE-/- Nrf2-/- mice was associated with a significant decrease in uptake of modified low density lipoproteins (AcLDL) by isolated macrophages from ApoE-/- Nrf2-/- mice. Furthermore, atherosclerotic plaques and isolated macrophages from ApoE-/- Nrf2-/- mice exhibited decreased expression of the scavenger receptor CD36. Conclusions: Nrf2 is pro-atherogenic in mice, despite its antioxidative function. The net pro-atherogenic effect of Nrf2 may be mediated via positive regulation of CD36. Our data demonstrates that the potential effects of Nrf2-targeted therapies on cardiovascular disease need to be investigated.9 page(s

Comparative Functional Genomics Analysis of NNK Tobacco-Carcinogen Induced Lung Adenocarcinoma Development in Gprc5a-Knockout Mice

Background: Improved understanding of lung cancer development and progression, including insights from studies of animal models, are needed to combat this fatal disease. Previously, we found that mice with a knockout (KO) of G-protein coupled receptor 5A (Gprc5a) develop lung tumors after a long latent period (12 to 24 months). Methodology/Principal Findings: To determine whether a tobacco carcinogen will enhance tumorigenesis in this model, we administered 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) i.p. to 2-months old Gprc5a-KO mice and sacrificed groups (n = 5) of mice at 6, 9, 12, and 18 months later. Compared to control Gprc5a-KO mice, NNK-treated mice developed lung tumors at least 6 months earlier, exhibited 2- to 4-fold increased tumor incidence and multiplicity, and showed a dramatic increase in lesion size. A gene expression signature, NNK-ADC, of differentially expressed genes derived by transcriptome analysis of epithelial cell lines from normal lungs of Gprc5a-KO mice and from NNK-induced adenocarcinoma was highly similar to differential expression patterns observed between normal and tumorigenic human lung cells. The NNK-ADC expression signature also separated both mouse and human adenocarcinomas from adjacent normal lung tissues based on publicly available microarray datasets. A key feature of the signature, up-regulation of Ube2c, Mcm2, and Fen1, was validated in mouse normal lung and adenocarcinoma tissues and cells by immunohistochemistry and western blotting, respectively

Currículo de la pre secundaria en Timor Oriental y su articulación con la secundaria general

Problemas herdados nas últimas décadas conduziram Timor-Leste a reestruturar os currículos do ensino pré-secundário – EPS – e do secundário geral – ESG.1 Atendendo à importância de uma adequada articulação vertical ao longo dos ciclos de escolaridade e diante do cumprimento de uma primeira edição completa do EPS, importa estudar se tal currículo está alinhado com o do ESG, em particular no que respeita às Ciências e Tecnologia. Este artigo centra-se na análise do currículo do EPS e na avaliação da sua articulação com o do ESG. Não obstante existam décalages entre o currículo prescrito, o implementado e o apropriado, é relevante haver sintonia no nível dos currículos para uma educação e formação de boa qualidade, fundamentais à consecução dos Objetivos de Desenvolvimento do Milénio.Problems inherited from the last decades have led Timor-Leste to restructure its pre-secondary – EPS – and general secondary – ESG – curricula. Considering the importance of an adequate vertical articulation throughout the schooling cycles and before the conclusion of the first complete edition of the EPS, it is necessary to study if such a curriculum is aligned with the one of the ESG, in particular with regard to Science and Technology. This article focuses on the analysis of the EPS curriculum and the evaluation of its articulation with the one of ESG. Notwithstanding the décalages among the prescribed, the implemented and the appropriate curricula, it is relevant to have a fine-tuning at this level to ensure good quality education and training, essential to achieve the millennium development goals.Des problèmes hérités des dernières décennies ont conduit le Timor-Oriental à restructurer ses programmes d’enseignement présecondaire – EPS –, ainsi que ceux de l’enseignement secondaire général – ESG. Compte tenu de l’importance d’une bonne articulation verticale tout au long des cycles scolaires etvu qu’une première édition complète de l’EPS a déjà été mise en place, il est important de vérifier si ce programme s’aligne bien à celui de l’ESG, particulièrement en ce qui concerne les Sciences et la Technologie. Cet article se concentre sur l’analyse du programme de l’EPS et sur l’évaluation de son articulation avec celui de l’ESG. Nonobstant certains décalages entre le programme prescrit, celui qui a été mis en œuvre et celui qui est approprié, il est nécessaire que les programmes soient en phase pour atteindre une éducation et une formation de qualité, fondamentales pour la réalisation des Objectifs du Millénaire pour le Développement.Problemas heredados en las últimas décadas hicieron que Timor Oriental reestructurase los currículos de la educación pre secundaria – EPS – y de la secundaria general – ESG. En función de la importancia de una adecuada articulación vertical a lo largo de los ciclos de escolaridad y frente al cumplimiento de una primera edición completa do EPS, importa estudiar si tal currículo está alineado con el del ESG, en particular en lo que concierne a las Ciencias y Tecnología. Este artículo se centra en el análisis del currículo del EPS y en la evaluación de su articulación con el del ESG. No obstante la existencia de décalages entre el currículo prescrito, el implementado y el apropiado, es relevante que haya sintonía a nivel de los currículos para una educación y formación de calidad, fundamentales para la consecución de los Objetivos de Desarrollo del Milenio

Frequent epigenetic inactivation of Wnt antagonist genes in breast cancer

Although mutation of APC or CTNNB1 (β-catenin) is rare in breast cancer, activation of Wnt signalling is nonetheless thought to play an important role in breast tumorigenesis, and epigenetic silencing of Wnt antagonist genes, including the secreted frizzled-related protein (SFRP) and Dickkopf (DKK) families, has been observed in various tumours. In breast cancer, frequent methylation and silencing of SFRP1 was recently documented; however, altered expression of other Wnt antagonist genes is largely unknown. In the present study, we found frequent methylation of SFRP family genes in breast cancer cell lines (SFRP1, 7 out of 11, 64%; SFRP2, 11 out of 11, 100%; SFRP5, 10 out of 11, 91%) and primary breast tumours (SFRP1, 31 out of 78, 40%; SFRP2, 60 out of 78, 77%; SFRP5, 55 out of 78, 71%). We also observed methylation of DKK1, although less frequently, in cell lines (3 out of 11, 27%) and primary tumours (15 out of 78, 19%). Breast cancer cell lines express various Wnt ligands, and overexpression of SFRPs inhibited cancer cell growth. In addition, overexpression of a β-catenin mutant and depletion of SFRP1 using small interfering RNA synergistically upregulated transcriptional activity of T-cell factor/lymphocyte enhancer factor. Our results confirm the frequent methylation and silencing of Wnt antagonist genes in breast cancer, and suggest that their loss of function contributes to activation of Wnt signalling in breast carcinogenesis