阻止抬升盆地原油生物降解的深埋灭菌作用

微生物活动造成的原油生物降解作用发生地球中大多数的油藏中，人们认为生物降解作用大大降低油藏中原油的质量，为成功寻找工业油藏，理解地质建造中生物降解作用发生的条件与过程是十分重要的，尽管最近的研究推测微生物活动在温度在150℃仍能有效地发生，但是人们普遍认为在地质时代，有效的石油生物降解作用通常发生在温度低于80℃的储层中，然而奇怪的是在温度低于80℃的储层中，还可发现未降解的原油，本文收集了一些油藏中有关生物降解程度的数据，发现未降角原油局限于埋藏浅的冷盆地，这些盆地曾是地球中更深，更热的部位，后经抬升作用形成的，我们认为这石油储层在深埋过程中，在温度为80－90℃时经历了灭菌作用，使得深部生物圈中降解烃类的生物停止活动，尽管这些储层后期抬升到较冷的部位并再次发生石油充注，也不会发生生物降解作用，表明灭菌后的沉积物不再适合降解烃类的细菌生长。     

HLA-DR mismatching correlates with early cardiac allograft rejection, incidence, and graft survival when high-confidence-level serological DR typing is used

To determine if cardiac allograft outcome is improved among patients with fewer HLA-DR mismatches with their donors, we studied 132 recipients of a primary cardiac allograft who were transplanted between December 1985 and December 1991. These recipients and their donors all had high-confidence-level serological HLA-DR typing, previously shown to correlate highly with DNA DR typing. Patients were divided in two groups based on the HLA-DR mismatch with their donors. Group I consisted of 78 patients with 1 or zero DR mismatch and group II of 54 patients with 2 DR mismatches. Allograft outcome measurements included incidence of moderate rejection, incidence of allograft vasculopathy at 12 months, cardiac function measured as left ventricular ejection fraction (LVEF) and cardiac index (CI), and actuarial graft survival up to 7 years. Groups I and group II were not different with regard to recipient age, donor age, ischemia time, pulmonary vascular resistance, sex, or PRA greater than 0%. Group II had a higher incidence of moderate rejection on the first-week biopsy (47% vs. 25%, P = 0.019), and during the first month (84% vs. 58%, P = 0.006), but no difference was found in frequency of rejection from months 2 to 12. LVEF was not different in the groups at any point. CI was better in group I at 12 months (2.76 vs. 2.5, P = 0.03). No statistically significant difference was found in incidence of allograft vasculopathy (17% vs. 26%, P = 0.204). Actual graft survival at 1 year was better for group I (91% vs. 74%, P = 0.008), and actuarial graft survival at 6 years also favored group I (76% vs. 56%, P = 0.04). Using high-confidence-level serological HLA-DR typing assignments we demonstrated that HLA-DR mismatching correlates highly with cardiac allograft outcome. Implications are that heart transplant survival could be improved if prospective matching were feasible and prioritized or if immunosuppression were tailored to the HLA-DR match.     

Long-term static testing of an FRP prototype highway structure

In recent years it has become apparent that the labour and maintenance costs of highway structures fabricated from conventional constructional materials (i.e. steel and concrete) are rising, and therefore the whole life cost of these structures is being significantly affected. Highway structures manufactured from advanced composite materials provide a viable solution to reduce substantially both the labour and the maintenance costs, whilst providing structures that behave in accordance with the present British code of practice for highway structures.

The principle objectives of the investigations were to undertake experimentally and to verify, where applicable, numerically the suitability of advanced fibre-reinforced polymer (FRP) composite materials manufactured in the form of box beams for use as highway structures. It was also important to research into any unique behaviour exhibited by the FRP structures while under test and to develop relevant theoretical models and formulae to characterize completely this behaviour.

The composite box beam showed no signs of global deterioration and generally behaved as predicted; the short term stiffness of the beam measured at specific times during the test did not decrease to any extent. There was some local flexural cracking in the connectors at the position of the applied loads, but this can be eliminated by design. The creep and deflections of the beam at the end of the test were well within acceptable limits.     

Role of imidazoline receptors in the cardiovascular actions of moxonidine, rilmenidine and clonidine in conscious rabbits

The present study in conscious rabbits with intracisternal (i.c.) catheters sought to determine the relative contribution of the I1 subtype of imidazoline receptors (IR) and alpha 2 adrenoceptors to the hypotensive effects of rilmenidine, clonidine and moxonidine with an I1-IR/alpha 2 adrenoceptor antagonist efaroxan and a specific alpha 2 adrenoceptor antagonist 2-methoxyidazoxan (2-MI). The alpha 2 adrenoceptor antagonist effect of efaroxan was compared with 2-MI by performing cumulative dose-response curves in the presence of alpha-methyldopa (400 micrograms/kg i.c.). 2-MI was 5.6 times more potent than efaroxan at reversing 75% of the hypotension elicited by alpha-methyldopa (P < .025). This dose ratio was used to match doses of efaroxan and 2-MI for similar alpha 2 adrenoceptor blockade. The effects of efaroxan (4.1, 13, 41 micrograms/kg i.c.) and 2-MI (0.74, 2.3, 7.4 micrograms/kg i.c.) were investigated on a single i.c. dose of rilmenidine (12 micrograms/kg), clonidine (0.75 microgram/kg) and moxonidine (0.51 microgram/kg). These doses of the antihypertensive agents, which were determined from cumulative dose-response curves, produce 90% of the maximum hypotension. Efaroxan was more effective at reversing the hypotension induced by moxonidine and rilmenidine than was 2-MI (P < .01). These findings suggest that rilmenidine and moxonidine act predominantly via IR. By contrast, 2-MI was more effective at reversing the clonidine-induced hypotension than was efaroxan (P < .001), suggesting that clonidine acts mainly via alpha 2 adrenoceptors in conscious normotensive rabbits. Thus, a higher selectivity of the second generation agents moxonidine and rilmenidine for I1-IR over alpha 2 adrenoceptors, compared with the first generation agent clonidine, appears to be necessary for this effect to be manifested in their hypotensive actions.     

Improvement of the engineering properties of asphalt pavements using a ‘soft’ compaction technique (AMIR-Compaction)

In most countries of the world asphalt pavement of road networks represents the biggest single investment in the transportation system. In Canada, asphalt pavement built over the past decade is worth more than 70 billion dollars (in 1984 dollars). In order to maintain the current road network at the present level of service and prevent it from further deterioration, over 6 billion dollars is needed anually.

Traditionally, asphalt overlays are widely used to rehabilitate existing deteriorated pavements. Unfortunately the new overlays have been observed to fail in a relatively short time. Thus the investment in overlays is lost.

Recent research based on the concept of relative rigidity has indicated that the rapid deterioration of new asphalt overlays is directly related to current construction equipment. It has been shown analytically and experimentally that steel rollers used in compacting the asphalt layer will result in surface cracks during construction. Traffic and environmental influences will accelerate the failure of the new layer.

This paper presents the results of a testing programme evaluating the engineering properties of asphalt slabs compacted by a new method using a compactor termed AMIR. The results showed that the AMIR compactor will prevent the formation of constitution cracks resulting in an increase of indirect tensile strength of 10% and an increase of direct tensile strength of up to 60% when compared to steel roller compacted asphalt slabs.     

压力容器用封头制造质量控制和专业化生产发展方向

中国法规首次对压力容器等特种设备用封头实施制造资格许可和强制的监督检验制度。本文根据法规标准的规定,对压力容器封头制造质量控制和专业化生产发展方向的要求作一系统的综述,以提高压力容器产品的整体质量,确保特种设备安全万无一失。     

Spatio‐temporal trends of nutrients and physico‐chemical parameters on lake ecosystem and fisheries prior to onset of cage farming and re‐opening of the Mbita passage in the Nyanza Gulf of Lake Victoria

Many large lake ecosystems are experiencing increasing eutrophication and persistent cyanobacteria‐dominated algal blooms affecting their water quality and ecosystem productivity because of widespread non‐point and point nutrient sources. Accordingly, the present study utilized data of July 2003 and January–February 2004, as well as previous measurements of nutrients and physico‐chemical variables (electrical conductivity, dissolved oxygen, temperature, pH, turbidity and chlorophyll‐a), to characterize the spatial and temporal trends, as a means of better understanding the factors influencing lake environmental conditions, as support tools for long‐term ecosystem management and for better understanding the long‐term trends and effects. Inshore gulf areas were found to represent zones of maximum nutrient concentrations, compared to the deep main lake zones, with significant inter‐parameter correlations. Phosphorus, silicon and chlorophyll‐a concentrations were significantly correlated. Water electrical conductivity was also significantly and positively correlated with soluble reactive silicon (SRSi), alkalinity hardness DO, while exhibiting a negative association with water transparency. Water turbidity and transparency, electrical conductivity, and SRSi concentrations clearly describe a gradient from the gulf into the main lake. For such a shallow gulf, these findings suggest primary productivity is influenced mainly by the availability of nutrients, light transparency and the extent of availability of resuspended nutrients. The increasing eutrophic state of Lake Victoria is a serious concern since it contributes to an increased potential of more frequent occurrences of cyanobacterial blooms, a potential public health risk to both humans and wildlife. Improved understanding of influences from previous fish species introductions and concomitant changes in indigenous fish species, increased lake basin population and anthropogenic activities, water hyacinth resurgences, sustainability of biodiversity, and current interests in cage farming, are among the major concerns and challenges facing the contemporary Lake Victoria. The trends regarding nutrients and physico‐chemical characteristics are intended to support better monitoring efforts and data to promote the lake's ecosystem services and the sustainable management of the lake ecosystem.     

Perceived interactivity leading to e-loyalty: Development of a model for cognitive–affective user responses

Novel applications of website interactivity are important to attract and retain online users. In this empirical study five designs for interactivity are examined using different web-poll interfaces. The goal of the investigation is to examine perceived interactivity in a model which includes most commonly tested cognitive elements such as efficiency and effectiveness, but augments this model with the inclusion of a cognitive–affective element for trust, and an affective element of enjoyment. More specifically, a model is created to validate the relationship of perceived interactivity (comprised of user control, user connectedness, and responsiveness of the web-poll application) to efficiency, effectiveness, trust and enjoyment, of the website. In turn, efficiency, effectiveness, trust, and enjoyment are tested for their influence on user behavioral intentions for e-loyalty. All relationships in the model are supported. In addition, exploratory evaluation of qualitative comments is conducted to investigate additional insights between the five web-poll treatments in this investigation. The research confirms the complexity of a model in which cognitive, cognitive–affective and affective elements are present, and advances knowledge on the consequences of perceived interactivity. In additional to theoretical advancements, the research has merit for web designers and online marketers regarding how to enhance interactive online web applications.     

Achieving greater anonymity in network latency

Each lnternet communication leaves trails that can be followed back to the user. Notably, anonymous communication schemes are purposed to hide users＇ identity as to personal, source, destination location and content information. Notably, no network capability is in existence to completely negate anonymity leakage in network latency[~l, thus, the minimization of anonymity leakage in network latency becomes critically salient. The purpose of this paper is to investigate network latency anonymity leaks, and propose practical techniques for their reduction. In this direction, the author investigate the following technical question： What implementation techniques can be configured to truly reduce anonymity leaks using deployable systems and exploiting the popular Tor security strategies.