Simulator-mediated acquisition of a dynamic control skill

Uses of stored skill-models to accelerate simulator-based real-time training in a control skill are discussed. A real-time coach must deliver advice at three levels: (1) what to do next, (2) what to watch for, and (3) what went wrong. Human learning and machine learning results are presented using different screen representations of a pole-and-cart balancing task.     

Low-temperature X-ray microanalysis of the differentiating vascular tissue in root tips of Lemna minor L

The fracture faces of bulk-frozen tissue offer a number of advantages for the analysis of diffusible elements. They are easy to prepare, remain uncontaminated, and, unlike most frozen-hydrated sections, can be shown to exist in a fully hydrated state throughout examination and analysis. Root tips of Lemna minor briefly treated with a polymeric cryoprotectant are quench frozen in melting nitrogen. Fractures are prepared using the AMRAY Biochamber, lightly etched if necessary to reveal surface detail and carbon coated while maintaining the specimen at 110 K. The frozen-hydrated fracture faces are analysed at 110 K using the P/B ratio method which is less sensitive to changes in surface geometry and variations in beam current. The method has been used to investigate the distribution of seven elements (Na+, Mg⁺⁺, P, S, Cl^?, K+ and Ca⁺⁺) in the developing vascular tissue of the root tip. The microprobe can measure relative elemental ratios at the cellular level and the results from this present study reveal important variations in different parts of the root. The younger, more actively dividing cells, appear to have a slightly higher concentration of diffusible ions in comparison to the somewhat older tissues which have begun to differentiate into what are presumed to be functional vascular elements.     

Mobilization of peripheral blood stem cells in children using G-CSF after carboplatin containing myelosuppressive chemotherapy

PURPOSE: Peripheral blood stem cell (PBSC) apheresis provides an alternative to autologous marrow harvest as a source of hematologic stem cells for transplantation in children with solid tumors. PATIENTS AND METHODS: Eight children with metastatic or recurrent solid tumors underwent 27 apheresis procedures. Recovery from myelosuppressive chemotherapy occurred without continuous daily growth factor support prior to mobilization. Granulocyte colony stimulating factor (G-CSF) at 16 microgs/kg/day was used to increase stem cells in the peripheral circulation. CD 34 positive cells, mononuclear cells (MNC), and CFU-GM were measured in the apheresis products. Prior chemotherapy was examined as a clinical factor that affected PBSC yield. RESULTS: A significant correlation was found between CD 34+/kg and CFU-GM/kg of the products (r = 0.758, P < 0.001). Patients receiving cumulative doses of carboplatin over 1,600 mg/m2 produced adequate MNC (1 x 10(8)/kg) but yielded significantly less CD 34+ cells or CFU-GM than those patients receiving less carboplatin. Prior doses of etoposide and ifosfamide did not effect PBSC yield. CONCLUSIONS: The mobilization technique was well tolerated, and the products obtained produced trilineage engraftment in the patients that underwent peripheral blood stem cell transplantation. Peripheral blood stem cell apheresis in children can be optimized by selection of appropriate candidates and mobilization with G-CSF after an absence of hematopoietic growth factor support.     

CYP1B1 Augments the Mesenchymal,Claudin-Low,and Chemoresistant Phenotypes of Triple-Negative Breast Cancer Cells

Cytochrome P4501B1 (CYP1B1) is elevated in breast cancer. Studies indicate a relationship between CYP1B1 and aggressive cancer phenotypes. Here, we report on in vitro studies in triple-negative breast cancer cell lines, where knockdown (KD) of CYP1B1 was used to determine the influence of its expression on invasive cell phenotypes. CYP1B1 KD in MDA-MB-231 cells resulted in the loss of mesenchymal morphology, altered expression of epithelial–mesenchymal genes, and increased claudin (CLDN) RNA and protein. CYP1B1 KD cells had increased cell-to-cell contact and paracellular barrier function, a reduced rate of cell proliferation, abrogation of migratory and invasive activity, and diminished spheroid formation. Analysis of clinical breast cancer tumor samples revealed an association between tumors exhibiting higher CYP1B1 RNA levels and diminished overall and disease-free survival. Tumor expression of CYP1B1 was inversely associated with CLDN7 expression, and CYP1B1^HI/CLDN7^LOW identified patients with lower median survival. Cells with CYP1B1 KD had an enhanced chemosensitivity to paclitaxel, 5-fluorouracil, and cisplatin. Our findings that CYP1B1 KD can increase chemosensitivity points to therapeutic targeting of this enzyme. CYP1B1 inhibitors in combination with chemotherapeutic drugs may provide a novel targeted and effective approach to adjuvant or neoadjuvant therapy against certain forms of highly metastatic breast cancer.     

Generalised rely-guarantee concurrency: an algebraic foundation

The rely-guarantee technique allows one to reason compositionally about concurrent programs. To handle interference the technique makes use of rely and guarantee conditions, both of which are binary relations on states. A rely condition is an assumption that the environment performs only atomic steps satisfying the rely relation and a guarantee is a commitment that every atomic step the program makes satisfies the guarantee relation. In order to investigate rely-guarantee reasoning more generally, in this paper we allow interference to be represented by a process rather than a relation and hence derive more general rely-guarantee laws. The paper makes use of a weak conjunction operator between processes, which generalises a guarantee relation to a guarantee process, and introduces a rely quotient operator, which generalises a rely relation to a process. The paper focuses on the algebraic properties of the general rely-guarantee theory. The Jones-style rely-guarantee theory can be interpreted as a model of the general algebraic theory and hence the general laws presented here hold for that theory.     

Effect of psychrotrophic bacteria and of an isolated protease from Pseudomonas fluorescens M3/6 on the plasmin system of fresh milk

In the present study, we investigated the effect of Pseudomonas spp. growth on the plasmin enzymatic system in casein and whey fractions of fresh milk. Two bacterial strains, Pseudomonas spp. SRM28A and Pseudomonas fluorescens M3/6, were inoculated at a level of approximately 10(3) cfu/ml into fresh milk and incubated at 7 degrees C for 3 d. Bacterial counts were approximately 10(8) cfu/ml by d 3. Samples collected every 24 h were treated to separate the casein from the whey fraction. Casein and whey fractions were subjected to electrophoresis to visualize protein breakdown and plasmin activity and to colorimetric assays to quantify plasmin-related activities. With psychrotrophic bacterial growth, plasmin levels in casein fractions decreased significantly and in whey fractions increased then decreased significantly. Fresh milk results were similar for the two strains and were similar to earlier results with reconstituted nonfat dry milk. A transmission electron microscopy study by immunocytochemistry showed the presence of plasmin in casein micelles and its disappearance upon microbial growth in the milk. We hypothesized that extracellular microbial proteases produced by psychrotrophic microorganisms are responsible for this effect. To confirm this, an extracellular bacterial protease was isolated from Pseudomonas fluorescens M3/6 by ammonium sulfate fractionation and ion-exchange chromatography and incubated with fresh milk. Milk samples analyzed during incubation with the protease had significantly increased plasmin and plasminogen activities in the whey fraction within 5 h of incubation, while differences in activities in the casein fraction occurred at time 7.5 h for plasmin activity and 10 h of incubation for plasminogen activity. These quantitative data were supported by plasmin activity as visualized by casein-SDS-PAGE. These results suggest that growth of the Pseudomonas strains in fresh milk, and particularly their production of extracellular proteases, may be a causative factor in the release of plasmin from the casein micelle. Such plasmin release could affect the quality of cheeses and other food products that utilize dairy ingredients.     

注入信号频率对注入式定子接地保护的影响

为研究注入信号频率对发电机注入式接地保护测量灵敏度、测量误差方面和保护注入功率的影响,得到注入式定子接地保护外加注入源频率的最佳选择范围,提升注入式定子接地保护的测量精度.通过MATLAB/SIMULINK模块仿真计算分析说明了采用电流判据的局限性,并得出注入信号的最佳选择范围.结果表明:注入信号的最佳选择范围低频区间...     

一维碲纳米棒的溶剂热合成

用一缩二乙二醇作为溶剂,以碲粉为原料,通过溶剂热反应合成了一维碲纳米晶体,讨论了温度对碲纳米晶体形貌的影响。结果发现,在160℃的温度下,产物大小均匀,高长径比的一维碲纳米棒的产量最高。     

Microstructural Changes and Kinetics of Reduction of Hematite to Magnetite in CO/CO2 Gas Atmospheres

Metallurgical and Materials Transactions B - The microstructures of porous magnetite formed on gaseous reduction of dense hematite have been examined using high-resolution scanning electron...     

Microfluidic switchboards with integrated inertial pumps

Arrays of H-shaped microfluidic channels connecting two different fluidic reservoirs have been built with silicon/SU8 microfabrication technologies utilized in production of thermal inkjet printheads. The fluids are delivered to the channels via slots etched through the silicon wafer. Every H-shaped channel comprises four thermal inkjet resistors, one in each of the four legs. The resistors vaporize water and generate drive bubbles that pump the fluids from the bulk reservoirs into and out of the channels. By varying relative frequencies of the four pumps, input fluids can be routed to any part of the network in any proportion. Several fluidic operations including dilution, mixing, dynamic valving, and routing have been demonstrated. Thus, a fully integrated microfluidic switchboard that does not require external sources of mechanical power has been achieved. A matrix formalism to describe flow in complex switchboards has been developed and tested.