Synthesis and biological activity of folic acid and methotrexate analogues containing L-threo-(2S,4S)-4-fluoroglutamic acid and DL-3,3-difluoroglutamic acid

Clinical and pathological features of 52 infants and children with atypical teratoid/rhabdoid tumor (ATT/RhT) of the central nervous system are defined. This tumor is typically misdiagnosed as a primitive neuroectodermal tumor (PNET) primarily because 70% of ATT/RhTs contain fields indistinguishable from classic PNETs. Separation of these two tumor types is crucial because the prognosis for ATT/RhT is given even when treatment includes surgery with or without radio and/or chemotherapy. These tumors are most common in infants less than 2 years of age. The cases described in this study arose in intracranially in all but one instance, although one-third had already spread throughout the subarachnoid space at presentation. Clinical signs and symptoms and radiological features do not distinguish ATT/RhTs from PNETs. The tumors are composed entirely (13%) or partly (77%) or rhabdoid cells. Seventy percent contains fields of typical PNET alone or in combinations with mesenchymal and/r epithelial elements. The immunohistochemical profile is unique: epithelial membrane antigen, vimentin, and smooth-muscle actin are positive in the majority of tumors and markers for germ-cell tumors are consistently negative. Abnormalities of chromosome 22 distinguish ATT/RhTs from PNETs, which typically display an i(17q) abnormality.     

Aqueous Precipitation of Spherical Zinc Oxide Powders for Varistor Applications

Aqueous precipitation has been used to prepare spherical ZnO particles. These powders have been shown to be suitable for use in the preparation of varistors. The uniform size distribution and uniform coating of these powders with the appropriate dopants allowed fabrication of varistors with improved properties over those fabricated from conventionally ball-milled and calcined powders. The improved properties were a high coefficient of nonlinearity (∼44) in the nonohmic region, a sharp change in electrical behavior from ohmic to nonohmic, and a high resistivity (5×10¹² SOM°m) at low voltages.     

Development and Evolution of Nanostructure in Bulk Thermoelectric Pb-Te-Sb Alloys

Motivated by reports of exceptionally high zT > 2 in thin film superlattices or “quantum well” materials with nanometer sized features, we have undertaken a study of composite materials with nanoscale features that promise to provide similar structures in bulk material. Nanometer scale layers of PbTe and Sb₂Te₃ with periodicities of 180 nm to 950 nm form when quenched eutectic PbTe-Sb₂Te₃ melt, crystallizing as Pb₂Sb₆Te₁₁, subsequently annealed. The lamellar spacing depends on the temperature and time of the anneal. The mechanism for the development of the nanostructures is probed by examining the fraction of material transformed as a function of anneal time. Preliminary analysis of the shape factor exponent reveals that the transformation to the nanostructured lamellae bears similarities to the thickening of very large plates. The coarsening of the lamellar spacing is also examined as a function of time and temperature.     

Strain differences in maintenance of cocaine self-administration and their relationship to novelty activity responses.

The authors previously demonstrated that Fischer 344 (F344) and Lewis inbred rats differ in acquisition of cocaine self-administration. Other studies show that acquisition and maintenance of drug self-administration are predicted by locomotor activity in a novel environment among outbred Sprague-Dawley rats. The present study was designed to determine whether this relationship extended to F344 and Lewis rats. In Experiment 1, F344, Lewis, and Sprague-Dawley rats were trained to self-administer cocaine and tested with several doses under fixed- and progressive-ratio schedules of reinforcement. Self-administered infusions and ineffective active lever presses--those emitted during infusion and time-out periods--were assessed. In Experiment 2, separate sets of rats of each strain were examined for locomotor responses (distance traveled and center time) under novelty conditions. Results show that F344 rats self-administer more cocaine than Lewis or Sprague-Dawley rats under both schedules and emit more ineffective lever presses--a possible measure of craving. Strain comparisons of locomotor responses suggest that center time, not activity, relates to self-administration behavior. Maintenance studies of cocaine self-administration rather than acquisition may better reflect vulnerability to addiction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

He-Ne激光与紫外线复合诱变桑黄菌原生质体的研究

对桑黄菌原生质体进行He-Ne激光与紫外复合诱变处理,经过3代筛选,筛选出了5株变异株S1~S5。5株变异株菌丝发酵产量比出发菌株均有所提高,S1比出发菌株增产64.06%;其中3株变异株多糖含量增加,多糖含量最高的菌株S4比出发菌株提高13.84%。酯酶同工酶分析表明变异株酯酶酶谱发生了变化,传代培养表明变异株具有较稳定的遗传性,正变异率估算表明He-Ne激光与紫外线复合诱变桑黄菌原生质体优于紫外线诱变。     

不同品种紫苏种子营养成分的分析

对植株叶面颜色分别为面青背紫及两面均紫的紫苏种子营养成分进行了测定,对氨基酸及脂肪酸组成进行了分析。结果表明,面青背紫紫苏种子水分、粗脂肪、总蛋白、总糖、纤维素及灰分质量分数分别为8.83%、27.49%、14.57%、9.85%、23.15%及4.01%;两面均紫紫苏种子的质量分数分别为8.49%、31.25%、17.82%、9.52%、21.08%及2.36%。氨基酸分析结果表明,这2个品种紫苏种子中Asp、Glu、Arg及Leu含量均较高,且Arg、Cys及Met质量分数差别显著。脂肪酸分析结果表明,面青背紫紫苏种子中棕榈酸、硬脂酸、油酸、亚油酸及α-亚麻酸质量分数分别为6.85%、4.37%、20.73%、17.87%及49.34%;两面均紫紫苏种子中质量分数分别为7.84%、3.31%、17.62%、17.03%及53.07%。矿物元素分析结果表明,2个品种紫苏种子中P含量最高,其次是Ca、K、Mg,而Cu及Zn含量较低。     

Testing the environmental Kuznets curve hypothesis: an empirical study for East African countries

ABSTRACT

The green economy aims to achieve economic growth and development without an adverse effect on the environment. The environmental Kuznets curve (EKC) hypothesis explains the relationship between economic activity and environmental degradation. Using the EKC hypothesis as a theoretical framework, this study tested the EKC hypothesis for 12 East African countries using the Pooled Mean Group (PMG) approach for the period from 1990 to 2013. The result shows that the relationship between per capita income and CO₂ emissions (a proxy for environmental degradation) is bell shaped and thus is an extended version of the original inverted U-shaped curve relationship between economic activities and environmental degradation. Hence, one can conclude that the economic activities in East African countries do not lead to CO₂ emissions. Therefore, environmental conservation policies, technological advancement and modern industrial policies are required to make the economic growth of East African countries effective in reducing CO₂ emissions.     

Integrated life-cycle design of building enclosures

In spite of the progress in developing methods and tools to support sustainable building design, there is still a lack of a formal approach to bridge the “no man’s land” gap between the traditional building engineering disciplines, and between these and the architecture, to achieve the level of building integration required for sustainability. This paper presents an integration framework that aims at facilitating the inclusion of life-cycle considerations in the design process from the outset, so that materials and systems are selected not only from environmentally friendly resources, but most importantly, to match service life performance expectations. The framework describes an iterative methodology to evaluate these expectations in practice, which is based on an understanding and modeling of the dynamics of the built environment to which materials, components, and systems are exposed. Quantitative methods and test protocols can be incorporated into the framework for assessing function-performance aspects of alternative solutions. Due to its complexity stemming from its inherent exposure to variable environmental loads and its multi-functionality, the framework focuses on addressing the life cycle of the building enclosure system. It is expected that the organization of the underlying principles of building life-cycle performance described in this paper will become a knowledge core that will facilitate a more integrated treatment of buildings in research, education, and practice.