An experiment to evaluate methods for estimating fossil fuel resources

Estimates of petroleum and natural gas resources vary substantially, both over time and across estimation methods. This paper develops a simulation model of global oil resources to evaluate different resource estimation techniques. Protocols for the Hubbert life cycle and USGS geological analogy methods are developed and applied to synthetic data generated by the model. It is shown that the Hubbert method can generate an accurate estimate as early as twenty years before the peak of global production, but the geological analogy approach overestimates the true resource base over the life cycle of the resource. The results show the applicability of simulation and the synthetic data approach to the problem of evaluating forecasting methods.     

基于输出时滞方法的采样数据系统故障估计

从时滞系统角度率先研究了一类非均匀采样数据系统的故障估计问题.首先,基于输出时滞方法将采样数据系统建模成具有时变时滞输出的连续时间系统;然后,通过分析自适应诊断观测器不再适用于此类连续时滞系统的原因,提出了一种能够保证估计误差指数收敛的增广故障估计滤波器设计新方法;并进一步研究了具有噪声干扰的采样数据系统的时变故障估计问题;最后,通过对某型飞控系统的仿真实验结果验证了所提方法的有效性.     

Modelling and representing: An artefactual approach to model-based representation

The recent discussion on scientific representation has focused on models and their relationship to the real world. It has been assumed that models give us knowledge because they represent their supposed real target systems. However, here agreement among philosophers of science has tended to end as they have presented widely different views on how representation should be understood. I will argue that the traditional representational approach is too limiting as regards the epistemic value of modelling given the focus on the relationship between a single model and its supposed target system, and the neglect of the actual representational means with which scientists construct models. I therefore suggest an alternative account of models as epistemic tools. This amounts to regarding them as concrete artefacts that are built by specific representational means and are constrained by their design in such a way that they facilitate the study of certain scientific questions, and learning from them by means of construction and manipulation.     

浅议我国入世后对国内建筑业的影响及其对策

本文简要论述了我国建筑市场将面临的新的发展机遇,分析了我国加入世界贸易组织后对建筑业的有利与不利因素,讨论了我国建筑业进入国际市场的前景,建议了应对策略和政府的政策导向。     

应用于微结构制造自治系统的流程自动生成

本文介绍计算机自动生成微结构制造流程的技术。微结构器件的种类繁多,不同器件的加工特点都不相同,即以中等复杂程度的CMOS结构而言,其制造流程就达到了几百个步骤之多,因此流程的生成技术是极具挑战性的。一个适用流程可按由简入繁的过程逐步形成。本文首先介绍了根据器件结构的特点,确定单元加工顺序的优先级方案;在单元加工顺序确定后,参照本文所定义的一个原型工艺库,可以将对单元的加工处理展开成局部的工艺步骤串;工艺步骤串连缀而成的初始工艺流程,经过一定的优化与适配工艺条件的之后,产生出在实践中能够直接使用的、详细的工艺流程卡。     

Nature of the FeO2 bonding in myoglobin: An overview from physical to clinical biochemistry

Summary The iron(II)-dioxygen bond in myoglobin and hemoglobin is a subject of wide interest. Studieas range from examinations of physical-chemical properties dependent on electronic structure, to investigations of stability as a function of oxygen supply. Stability properties are of particular importance in vivo, since the oxygenated form is known to be oxidized easily to the ferric form, which cannot be oxygenated and is therefore physiologically inactive.Kinetic and thermodynamic studies of the stability of native oxymyoglobin have revealed a new feature in FeO₂ bonding. In vivo. the iron center is always subject to a nucleophilic attack of the water molecule or hydroxyl ion, which can enter the heme pocket from the surrounding solvent, and thereby irreversibly displace the bound dioxygen from MbO₂ in the form of O ₂ ^– so that the iron is converted to the ferric form. A free energy diagram for the potential reactions of FeO₂ visualizes myoglobin as a molecular structure that can provide in solution the delicate balance of kinetic and thermodynamic factors necessary to stabilize reversible oxygenation, as opposed to irreversible autoxidation to metmyoglobin.     

Change in sensitivity to lipopolysaccharide during the differentiation of human monocytes to macrophages in vitro

Mononuclear phagocytes in distinct differentiation stages and cultured under different conditions were tested for their sensitivity towards lipopolysaccharide (LPS), using procoagulant activity (PCA) expression and tumor necrosis factor (TNF) production as indices. The response of mature monocyte-derived macrophages differed from that of freshly isolated monocytes 1) by higher levels of constititive PCA, 2) by responding to approximately 1,000-fold lower concentrations of LPS with PCA and TNF production, and 3) by a faster rise in PCA and TNF production. Due to the high constitutive level of PCA expression, the PCA stimulation index for LPS was low in macrophages when compared with that in monocytes. Thus, during differentiation to macrophages, human monocytes acquire increased sensitivity to LPS (2 orders of magnitude more sensitive than a sensitive turbidimetricLimulus amoebocyte lysate assay). This exquisite sensitivity to LPS is expressed regardless of whether LPS is offered in the presence or absence of lipopolysaccharide binding protein-containing serum. This points to as yet uncharacterized pathways of high affinity interaction between LPS and macrophages.     

Antibody to tumor necrosis factor (TNF) reduces endotoxin fever

Summary Antibody to tumor necrosis factor (TNF), injected intravenously, reduced endotoxin fever in the rabbit. The fever-reducing effect was apparent in the latter half of the febrile response.This work was supported by a Grants-in-Aid from the Ministry of Education, Science and Culture of Japan (Grant No. 62480112).     

LDPC码概述及若干理论和应用问题

低密度奇偶校验码（LDPC码）被普遍认为是当今最先进的一种纠错码（信道编码）。LDPC码,图模型,迭代译码的研究热潮已在全球流行有10年以上。这篇论文高度概括的简述了LDPC码的背景和基本知识,从一些独特的视角并联系多个领域提出一些对LDPC码相关知识的理解方法和见解主张,总结了LDPC码当今最新的研究进展。从理论和应用两方面提出作者认为非常有意义的研究问题。     

An agglutinin with unique specificity for N-glycolyl sialic acid residues of thyroglobulin in the hemolymph of a marine crabScylla serrata (Forskal)

A novel agglutinin with specificity for sialic acid sequence of sugars in thyroglobulin is identified in the hemolymph ofScylla serrata. The physico-chemical characteristics of its binding affinity, such as pH and temperature optima, and cationic requirements are defined. N-glycolyl neuraminic acid (NeuGc) (at 0.6 mM), in contrast to N-acetyl neuraminic acid (NeuAc) (at >5.0 mM), is the potent inhibitor of hemagglutination. Bovine and porcine thyroglobulins containing NeuGc, inhibited the agglutination. NeuGc-acid glycoprotein fraction (bovine) but not NeuAc-acid glycoprotein fraction (human) inhibited the hemagglutination. The inability of other NeuGc-glycoproteins (bovine submaxillary mucin) to inhibit the agglutination suggests that the agglutinin may also recognize glycosidic linkage associated with NeuGc. The potential of the agglutinin in identifying NeuGc containing human tumor associated antigens is discussed.     

美国气候变化技术计划(CCTP)新战略规划及其对我国的启示

美国气候变化技术计划(CCTP)于2006年9月公布了新的气候变化技术计划战略规划,新规划将通过捕集、减少以及储存的方式来控制温室气体的排放量。该计划中包含的技术有氢能源、生物提炼、清洁煤、碳储存、核分裂和聚变能等,这些技术以最基础的方式转化为国民经济价值,不仅能够改善气候变化,而且可以保证能源安全、空气污染以及其他紧迫需求。本文对美国气候变化技术计划战略规划的任务、目标、方法进行概要介绍,并论述了其对我国气候变化技术发展的重要启示。     

From MDR to MXR: new understanding of multidrug resistance systems, their properties and clinical significance

The ATP binding cassette (ABC) superfamily of membrane transporters is one of the largest protein classes known, and counts numerous proteins involved in the trafficking of biological molecules across cell membranes. The first known human ABC transporter was P-glycoprotein (P-gp), which confers multidrug resistance (MDR) to anticancer drugs. In recent years, we have obtained an increased understanding of the mechanism of action of P-gp as its ATPase activity, substrate specificity and pharmacokinetic interactions have been investigated. This review focuses on the functional characterization of P-gp, as well as other ABC transporters involved in MDR: the family of multidrug-resistance-associated proteins (MRP1-7), and the recently discovered ABC half-transporter MXR (also known as BCRP, ABCP and ABCG2). We describe recent progress in the analysis of protein structure-function relationships, and consider the conceptual problem of defining and identifying substrates and inhibitors of MDR. An in-depth discussion follows of how coupling of nucleotide hydrolysis to substrate transport takes place, and we propose a scheme for the mechanism of P-gp function. Finally, the clinical correlations, both for reversal of MDR in cancer and for drug delivery, are discussed.     

Responses of monkey,rabbit and dog internal carotid arteries to atrial natriuretic factor

Summary Effects of atrial natriuretic factor (ANF) on monkey, rabbit and dog internal carotid arteries were investigated. ANF caused a concentration-dependent relaxation in arterial strips submaximally precontracted with noradrenaline, 5-hydroxytryptamine, or high-potassium solution (10–30 mM). The response was greatest in the monkey arteries and least in the dog arteries. These results suggest that there is a marked species difference in the ANF-induced relaxation of the internal carotid arteries.     

Interpreting Aristotle on mixture: problems about elemental composition from Philoponus to Cooper

Aristotle’s On generation and corruption raises a vital question: how is mixture, or what we would now call chemical combination, possible? It also offers an outline of a solution to the problem and a set of criteria that a successful solution must meet. Understanding Aristotle’s solution and developing a viable peripatetic theory of chemical combination has been a source of controversy over the last two millennia. We describe seven criteria a peripatetic theory of mixture must satisfy: uniformity, recoverability, potentiality, equilibrium, alteration, incompleteness, and the ability to distinguish mixture from generation, corruption, juxtaposition, augmentation, and alteration. After surveying the theories of Philoponus (d. 574), Avicenna (d. 1037), Averroes (d. 1198), and John M. Cooper (fl. circa 2000), we argue for the merits of Richard Rufus of Cornwall’s theory. Rufus (fl. 1231-1256) was a little known scholastic philosopher who became a Franciscan theologian in 1238, after teaching Aristotelian natural philosophy as a secular master in Paris. Lecturing on Aristotle’s De generatione et corruptione, around the year 1235, he offered his students a solution to the problem of mixture that we believe satisfies Aristotle’s seven criteria.     

Genome-wide association study to identify SNPs conferring risk of myocardial infarction and their functional analyses

Myocardial infarction might result from the interactions of multiple genetic and environmental factors, none of which can cause disease solely by each of themselves. Although molecular biological studies revealed that a number of proteins are possibly involved in its pathogenesis, little, if any genetic findings have been reported so far. To reveal genetic backgrounds of myocardial infarction, we performed a large-scale, case-control association study using 92,788 gene-based single-nucleotide polymorphism (SNP) markers. We have identified functional SNPs within the lymphotoxin-α gene (LTA) located on chromosome 6p21 that conferred susceptibility to myocardial infarction. Furthermore, we could identify galectin-2 protein as a binding partner of LTA protein. The association study further revealed that a functional SNP in LGALS2 encoding galectin-2, which led to altered secretion of LTA, also indicated a risk of myocardial infarction. A combined strategy of genetic and molecularcellular biological approaches may be useful in clarifying pathogenesis of common diseases.Received 7 March 2005; received after revision 22 April 2005; accepted 25 April 2005     

西部退耕还林在生态环境建设中的地位与作用

根据中国西部由于自然和人为因素的影响,森林破坏严重,生态环境日趋恶化,经济基础薄弱。自然生态条件较差,发展水平仍然较低,西部各省人均国内生产总值无一达到全国平均水平,已严重的制约国民经济的发展和社会的安定团结的实际情况,分析了森林遭到破坏之后所造成的恶果对整个国民经济持续、快速和健康发展的影响,研究了退耕还林在整治国土中的巨大作用。     

Neuroserpin: a serpin to think about

Proteinases and their inhibitors play important roles in neural development, homeostasis and disease. Neuroserpin is a member of the serine proteinase inhibitor (serpin) superfamily that is secreted from the growth cones of neurons and inhibits the enzyme tissue-type plasminogen activator (tPA). The temporal and spatial pattern of neuroserpin expression suggests a role in synaptogenesis and is most prominent in areas of the brain that participate in learning, memory and behaviour. Neuroserpin also provides neuronal protection in pathologies such as cerebral ischaemia and epilepsy by preventing excessive activity of tPA. Point mutations in neuroserpin cause aberrant conformational transitions and the formation of loop-sheet polymers that are retained within the endoplasmic reticulum of neurons, forming inclusion bodies that underlie an autosomal dominant dementia that we have called familial encephalopathy with neuroserpin inclusion bodies or FENIB. We review here the role of neuroserpin and other proteinase inhibitors in brain development, function and disease. Received 25 February 2005; received after revision 16 November 2005; accepted 28 November 2005     

New approaches to therapy of cancers of the stomach,colon and pancreas based on peptide analogs

Cancers of the stomach, colon and exocrine pancreas are major international health problems and result in more than a million deaths worldwide each year. The therapies for these malignancies must be improved. The effects of gastrointestinal (GI) hormonal peptides and endogenous growth factors on these cancers were reviewed. Some GI peptides, including gastrin and gastrin-releasing peptide (GRP) (mammalian bombesin), appear to be involved in the growth of neoplasms of the GI tract. Certain growth factors such as insulin-like growth factor (IGF)-I, IGF-II and epidermal growth factor and their receptors that regulate cell proliferation are also implicated in the development and progression of GI cancers. Experimental investigations on gastric, colorectal and pancreatic cancers with analogs of somatostatin, antagonists of bombesin/GRP, antagonists of growth hormone-releasing hormone as well as cytotoxic peptides that can be targeted to peptide receptors on tumors were summarized. Clinical trials on peptide analogs in patients with gastric, colorectal and pancreatic cancers were reviewed and analyzed. It may be possible to develop new approaches to hormonal therapy of GI malignancies based on various peptide analogs.Received 20 November 2003; accepted 6 January 2004