Enthalpies of pyrolysis and oxidation of Athabasca oil sands

Thermal degradation of Athabasca oil sands, bitumen, and its fractions have been investigated in N₂and in air, at 25–600 °C and at pressures up to 6.9 MPa, using thermogravimetry (TG) and high pressure differential scanning calorimetry (PDSC). These conditions are likely to occur during in-situ recovery of bitumen by underground combustion processes. Two regions of weight loss are detected using both gases. The endothermic low temperature volatilization reactions (150–400 °C) absorbed +26 mJ mg^?1 for oil sand to +2319 mJ mg^?1 for medium oil. The heats of reaction for high-temperature cracking and volatilization reactions (400–550 °C) were similar. The heats of reaction for the low-temperature oxidation reactions (150–375 °C) were ?405 mJ mg^?1 for oil sand to ?30200mJ mg^?1 for medium oil. Values for the high-temperature oxidation reactions (400–550 °C) were slightly higher. Increasing the pressure of nitrogen and air caused an increase in the endothermicity and exothermicity of the respective reactions.     

叶丝风选工艺实用性评价

为评价叶丝风选工艺对卷烟综合质量的影响,在相同条件下,分别对薄板干燥和气流干燥出口叶丝进行了采用与不采用叶丝风选工艺的对比试验。结果表明:①风选能剔除叶丝中气流干燥产生的湿团和薄板干燥产生的焦片,烟丝纯净度可提高0.2百分点以上;②风选降低了高档卷烟香气的透发性,明显改善了低档卷烟的杂气、刺激性和余味,"散花(软蓝)"感官得分提高了0.8分;风选对卷烟烟气成分的影响不显著;③风选提高了叶丝填充能力,降低卷烟单箱消耗0.1kg以上。     

对于低机械谐振频率经纬仪控制算法的研究

通过分析机械谐振频率对经纬仪系统性能的影响,在传统的控制算法基础上,提出了一种改进的控制算法。该控制算法可以抑制低机械谐振频率对经纬仪系统性能的影响,提高经纬仪的闭环带宽及其稳定性和跟踪精度。实验表明,本文提出的改进的控制算法效果好于传统的控制算法。     

数控技术在普通机床改造中的应用

介绍了采用开环控制系统对传统CA6140车床改造的原理和改造中硬件电路及控制软件的设计、选用,以及如何采用微机对数据进行传递、反馈,从而提高了机床运行的可靠性。     

Magnetic shielding in a low-temperature torsion pendulum experiment

A new type of ether drift experiment searches for anomalous torques on a permanent magnet. A torsion pendulum is used at liquid helium temperature so that superconducting cylinders can be used to shield magnetic fields. Lead shields attenuate the earth's field, while Nb-Sn shields fastened to the pendulum contain the fields of the magnet. The paper describes the technique by which the earth's field can be reduced below 10(-4) G while simultaneously the moment of the magnet can be reduced by a factor of 7 x 10(4).     

Premenstrual syndromes

Premenstrual syndrome research has made a great deal of progress since 1983 when the criteria for the diagnosis were clearly defined. Confirming the diagnosis prospectively and ruling out other disorders was a major methodologic advance. The DSM-IV criteria for PMDD now help us identify and classify women who have severe psychologic symptoms during the premenstruum. Although we do not have a definitive cause for PMDD, the consensus is that it is the end result of a complex series of events mediated partly by the serotonin system and triggered by ovulation. Women who meet criteria for PMS, do not meet the criteria for PMDD, and do not have a concurrent disorder should be treated conservatively. Women who meet criteria for PMDD can be treated successfully with low-dose clomipramine, SSRIs, or GnRH-as with "add back" estrogen and progestins.     

Can pooled red cells be used for antibody screening of patients'' specimens?

In this article we report a very rare case of simultaneous and bilateral rupture of the quadriceps tendon in a 38-year-old patient. The initial diagnosis was "herniated vertebral disk". Although there was an extensive neurological and psychiatric examination in combination with several operations, it took almost 3 months until the real reason was found. In this case report we describe our postoperative treatment of early mobilization and compare it with other therapies.     

Chromosomal instability and its relationship to other end points of genomic instability

Chromosomal destabilization is one end point of the more general phenomenon of genomic instability. We previously established that chromosomal instability can manifest in clones derived from single progenitor cells several generations after X-irradiation. To understand the potential relationship between chromosomal destabilization and the other end points of genomic instability, we generated a series of chromosomally stable and unstable clones by exposure to X-rays. All clones were derived from the human-hamster hybrid line GM10115, which contains a single copy of human chromosome 4 in a background of 20-24 hamster chromosomes. These clones were then subjected to a series of assays to determine whether chromosomal instability is associated with a general "mutator phenotype" and whether it modulates other end points of genomic instability. Thus, we analyzed clones for sister chromatid exchange, delayed reproductive cell death, delayed mutation, mismatch repair, and delayed gene amplification. Statistical analyses performed on each group of chromosomally stable and unstable clones indicated that, although individual clones within each group were significantly different from unirradiated clones for many of the end points, there was no significant correlation between chromosomal instability and sister chromatid exchange, delayed mutation, and mismatch repair. Delayed gene amplification was found to be marginally correlated to chromosomal instability (P < 0.1), and delayed reproductive cell death (the persistent reduction in plating efficiency after irradiation) was found to be significantly correlated (P < 0.05). These correlations may be explained by chromosomal destabilization, which can mediate gene amplification and can result in cellular lethality. These data implicate multiple molecular and genetic pathways leading to different manifestations of genomic instability in GM10115 cells surviving exposure to DNA-damaging agents.     

Can the Shape of Nanoparticles Enable the Targeting to Cancer Cells over Healthy Cells?

Macropinocytosis is a consequence of oncogenic alterations of cancer cells while most healthy cells are non-macropinocytic. It is currently unclear whether macropinocytic cancer cells can be targeted rather than healthy cells, by adjusting the shape and size of nanoparticles. Herein, the endocytosis of two differently shaped nanoparticles; nanorods and nanospheres are compared in cancer and healthy cells. The cells are breast epithelial cancer cells (MCF7) and breast epithelial healthy cells (MCF10A) and pancreas cancer cells (PANC-1 cells) and non-tumourogenic patient-derived cancer-associated fibroblasts (CAFs). The endocytosis pathway is quantified by a combination of pair correlation microscopy and endocytosis inhibitors. MCF7 cells use clathrin-mediated endocytosis and macropinocytosis to take up the nanorods while MCF10A cells use predominantly clathrin-mediated endocytosis. Based on the comparison of endocytic behavior of cancer and healthy cells, MCF7 cells can be induced to take up more nanorods and suppress the metabolism and endocytosis of nanorods in MCF10A cells. The nanorods allow targeting to breast cancer MCF7 cells and pancreas cancer cells over the healthy cells. This study opens exciting possibilities for shape to target the cancer cells over healthy cells, by adjusting nanoparticle shape.     

A correlation for the solubility of hydrocarbons in water

A correlation has been developed for the solubility of C₄ to C₁₀ hydrocarbons in water at 25°C and atmospheric pressure. The excess Gibbs free energy is correlated in terms of an effective molar volume which is related to the actual molar volume adjusted to include the effects of the degree of branching, the number of olefinic and acetylenic bonds and the number of aromatic and cycloalkane rings. The root mean square deviation between 59 correlated and experimental solubilities is 20%. The range of solubilities is from 0.052 to 5150 g hydrocarbon per 10⁶ g water. The correlation provides a rational procedure for the estimation of solubility of other hydrocarbons.