通风机房峒室系统设计的合理性与性能测试的规范性

通风机性能现场测试的可能性、规范性和准确性很大程度上取决于通风机房与峒室系统设计的的合理性。本文结合通风机性能现场测试规范性提出了设计与改进通风机房与峒室系统的建议。图５，参３。     

Seborrhea-like dermatitis with psoriasiform elements caused by a mutation in ZNF750, encoding a putative C2H2 zinc finger protein

We describe an Israeli Jewish Moroccan family presenting with autosomal dominant seborrhea-like dermatosis with psoriasiform elements, including enhanced keratinocyte proliferation, parakeratosis, follicular plugging, Pityrosporum ovale overgrowth and dermal CD4 lymphocyte infiltrate. We mapped the disease gene to a 0.5-cM region overlapping the PSORS2 locus (17q25) and identified a frameshift mutation in ZNF750, which encodes a putative C2H2 zinc finger protein. ZNF750 is normally expressed in keratinocytes but not in fibroblasts and is barely detectable in CD4 lymphocytes.     

Role of the ubiquitin–proteasome system in the regulation of P2Y13 receptor expression: impact on hepatic HDL uptake

The protective effect of high density lipoproteins (HDL) against atherosclerosis is mainly attributed to their capacity to transport excess cholesterol from peripheral tissues back to the liver for further elimination into the bile, a process called reverse cholesterol transport (RCT). Recently, the importance of the P2Y₁₃ receptor (P2Y₁₃-R) was highlighted in HDL metabolism since HDL uptake by the liver was decreased in P2Y₁₃-R deficient mice, which translated into impaired RCT. Here, we investigated for the first time the molecular mechanisms regulating cell surface expression of P2Y₁₃-R. When transiently expressed, P2Y₁₃-R was mainly detected in the endoplasmic reticulum (ER) and strongly subjected to proteasome degradation while its homologous P2Y₁₂ receptor (P2Y₁₂-R) was efficiently targeted to the plasma membrane. We observed an inverse correlation between cell surface expression and ubiquitination level of P2Y₁₃-R in the ER, suggesting a close link between ubiquitination of P2Y₁₃-R and its efficient targeting to the plasma membrane. The C-terminus tail exchange between P2Y₁₃-R and P2Y₁₂-R strongly restored plasma membrane expression of P2Y₁₃-R, suggesting the involvement of the intra-cytoplasmic tail of P2Y₁₃-R in expression defect. Accordingly, proteasomal inhibition increased plasma membrane expression of functionally active P2Y₁₃-R in hepatocytes, and consequently stimulated P2Y₁₃-R-mediated HDL endocytosis. Importantly, proteasomal inhibition strongly potentiated HDL hepatic uptake (>200 %) in wild-type but not in P2Y₁₃-R-deficient mice, thus reinforcing the role of P2Y₁₃-R expression in regulating HDL metabolism. Therefore, specific inhibition of the ubiquitin–proteasome system might be a novel powerful HDL therapy to enhance P2Y₁₃-R expression and consequently promote the overall RCT.     

Modification of clonazepam anticonvulsive activity by its association with other anti-epileptic drugs

Summary The modification of the anti-epileptic activity of clonazepam by other anticonvulsivants is studied. The results vary according to the drug and technique used. The usefulness of the 2 techniques employed is discussed.     

Inhibitory effect of exogenous histones on cellular growth and DNA synthesis in Chlamydomonas reinhardtii.]

The addition of exogenous histones to synchronous culture of Chlamydomonas reinhardtii, at the beginning of the cell cycle, leads to the death of the cells. The same amount of histones added in the middle of the cycle, only blocks the cell division. The mechanism of this inhibition effect of the histones could involve a block at the level of the chloroplast DNA replication.     

A salmonella protein antagonizes Rac-1 and Cdc42 to mediate host-cell recovery after bacterial invasion.

An essential feature of the bacterial pathogen Salmonella spp. is its ability to enter cells that are normally non-phagocytic, such as those of the intestinal epithelium. The bacterium achieves entry by delivering effector proteins into the host-cell cytosol by means of a specialized protein-secretion system (termed type III), which causes reorganization of the cell's actin cytoskeleton and ruffling of its membrane. One of the bacterial effectors that stimulates these cellular responses is SopE, which acts as a guanyl-nucleotide-exchange factor on Rho GTPase proteins such as Cdc42 and Rac. As the actin-cytoskeleton reorganization induced by Salmonella is reversible and short-lived, infected cells regain their normal architecture after bacterial internalization. We show here that the S. Typhimurium effector protein SptP, which is delivered to the host-cell cytosol by the type-III secretion system, is directly responsible for the reversal of the actin cytoskeletal changes induced by the bacterium. SptP exerts this function by acting as a GTPase-activating protein (GAP) for Rac-1 and Cdc42.     

Between Kepler and Newton: Hooke’s ‘principles of congruity and incongruity’ and the naturalization of mathematics

ABSTRACT

Robert Hooke’s development of the theory of matter-as-vibration provides coherence to a career in natural philosophy which is commonly perceived as scattered and haphazard. It also highlights aspects of his work for which he is rarely credited: besides the creative speculative imagination and practical-instrumental ingenuity for which he is known, it displays lucid and consistent theoretical thought and mathematical skills. Most generally and importantly, however, Hooke’s ‘Principles?…?of Congruity and Incongruity of bodies’ represent a uniquely powerful approach to the most pressing challenge of the New Science: legitimizing the application of mathematics to the study of nature. This challenge required reshaping the mathematical practices and procedures; an epistemological framework supporting these practices; and a metaphysics which could make sense of this epistemology. Hooke’s ‘Uniform Geometrical or Mechanical Method’ was a bold attempt to answer the three challenges together, by interweaving mathematics through physics into metaphysics and epistemology. Mathematics, in his rendition, was neither an abstract and ideal structure (as it was for Kepler), nor a wholly-flexible, artificial human tool (as it was for Newton). It drew its power from being contingent on the particularities of the material world.