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Oestrogen-androgen crosstalk in the pathophysiology oferectile dysfunction

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Asian Journal of Andrology 2003年第4期5卷 307-313页

作者： B Srilatha PG Adaikan Department of Obstetrics & Gynaecology national university of singapore 5 lower kent ridge road Singapore 119074Department of Obstetrics & Gynaecology National University of Singapore 5 Lower Kent Ridge Road Singapore 119074

Ageing in man is associated with a decline in testosterone following changes in the hypothalamo-pituitary testicular axis. This may offset the physiologic equilibrium between oestrogen and androgen and at some point when the ratio of free testosterone to oestradiol reaches a critical level, the oestrogenic gonadotropin suppressive effect predominates with decreased release of FSH and LH. Adding to this endocrinal complexity is the continued peripheral conversion to oestradiol through aromatisation. Although the androgen deficiency is not the sole cause for impotence in the elderly, there is a gradual decrease in nocturnal penile tumescence (NPT) and spontaneous morning erections with ageing. Despite the age related increase in oestrogen levels, the information on the pathophysiological role of the 'female hormone' in erectile dysfunction has been scanty. Together with our identification of oestrogen receptors within the penile cavernosum, we have delineated dysfunctional changes on male erection mediated by oestradiol. These findings parallel the recent concerns over environmental oestrogens on fertility declines in young men. Oestrogenic activity is also present in plants and thereby in human diet. These phytoestrogens are structurally and functionally similar to oestradiol and more potent than the environmental oestrogenic chemicals such as organochlorine and phenolic compounds. Thus in the light of growing concerns of possible compromising effects on sexuality by endogenous and environmental oestrogens, we are faced with the scientific need to delineate their role on the mechanism of male erectile pathway in health and disease for clinical correlates and prognostics.

关键词： oestrogen environmental oestrogens oestrogen receptor testosterone functional crosstalk erectile dysfunction

NANO-INDENTATION STUDIES OF TRANSPARENT CONDUCTING OXIDE THIN FILMS

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NANO-INDENTATION STUDIES OF TRANSPARENT CONDUCTING OXIDE THI...

Optimization of Multi-Join Queries in Shared-Nothing Systems

第8届国际材联电子材料国际研讨会

作者： Kaiyang Zeng Furong Zhu Jianqiao Hu Lu Shen Keran Zhang Hao Gong Institute of Materials Research and Engineering 3 Research Link singapore 117602 Dept. of Mat.Sciences national university of singapore lower kent ridge road singapore 119260

＜正＞ Transparent conductive oxide （TCO） thin films have widespread applications due to their unique properties of low electrical resistivity and high optical transmission in the visible spectrum range. TCO films have been used in photovoltaic devices, liquid crystal displays and organic light emitting diodes. It is well known that the optical, electrical, mechanical and morphological properties of TCO films have direct implications for determining and improving the device performance and reliability. Much effort has been

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Journal of Computer Science & Technology 1995年第2期10卷 149-162页

作者： Kian-Lee Tan(Department of Information Systems and Computer Science, national university ofsingapore, lower kent ridge road, singapore 0511) Department of Information Systems and Computer Science National University of Singapore Singapore

This paper proposes a semi-greedy framework for optimizing multi-joinqueries in shared-nothing systems. The plan generated by the framework com-prises several pipelines, each performing several joins. The framework deter-mines the 'optimal' number of joins to be performed in each pipeline. Thedecisions are made based on the cost estimation of the entire processing *** ekisting optimization algorithms are extended under the framework. Ananalytical model is presented and used to compare the quality of plans producedby each optimization algorithm. Our study shows that the new algorithms out-perform their counterparts that are not extended.

关键词： Multi-join optimization shared-nothing systems pipelining,hash join segmented right-deep tree

Translational Semantics for a Conceptual Level Query Language

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Journal of Computer Science & Technology 1995年第2期10卷 175-187页

作者： $Hock C. Chan(Department of Information Systems and Computer Science, national university ofsingapore, lower kent ridge road, singapore 0511) Department of Information Systems and Computer Science National University of Singapore Singapore

A conceptual level database language for the entity relationship (ER) modelimplicitly contains integrities basic to ER concepts and special retrieval seman-tics for inheritances of attributes and relationships. Prolog, which belongs tothe logical and physical level, cannot be used as a foundation to directly definethe database language. It is shown how Prolog can be enhanced to under-stand the concepts of entities, relationships, attributes and is-a *** enhanced Prolog is then used as a foundation to define the semantics of adatabase query language for the ER model. The three basic functions of modelspecification, updates and retrievas are defined.

关键词： Conceptual level query language semantics logic entityrelationship model abstraction level ER calculus

Influence of Coolant on Cutting Tool Performance

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Journal of Materials Science & Technology 1997年第3期13卷 199-205页

作者： K.H.W.Seah and X.Li(Dept. of Mechanical and Production Engineering, national university of singapore, 10 kent ridge Crescent,singapore 119260) Dept. of Mechanical and Production Engineering National University of Singapore 10 Kent Ridge Crescent Singapore 119260 Singapore

This paper reports a Study carried out to substantiate or refute the belief that when coolant is applied, the cutting performance is actually improved. Experiments on cutting forces and chip geometry were conducted in which AISI 1050 Steel was machined by turning using P30 uncoated tungsten carbide tools. Experiments were performed on a CNC Okuma LH35-N lathe undermachining conditions commonly used in workshops in singapore and many other parts of the world.

关键词： Tool Influence of Coolant on Cutting Tool Performance

CONVERGENCE OF CASCADE ALGORITHMS AND SMOOTHNESS OF REFINABLE DISTRIBUTIONS

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Chinese Annals of Mathematics,Series B 2003年第3期24卷 367-386页

作者： SUN QIYU Department of Mathematics, university of Houston, Houston, TX 77204, USA. Department of Mathematics, national university of singapore, 10 kent ridge Crescent, 119260, singapore. Department of Mathematics University of Houston TX 77204 USA Department of Mathematics National University of Singapore 10 Kent Ridge Crescent 119260 Singapore

In this paper, the author at first develops a method to study convergence of the cascadealgorithm in a Banach space without stable assumption on the initial (see Theorem 2.1), andthen applies the previous result on the convergence to characterizing compactly supportedrefinable distributions in fractional Sobolev spaces and Holder continuous spaces (see Theorems3.1, 3.3, and 3.4). Finally the author applies the above characterization to choosing appropriateinitial to guarantee the convergence of the cascade algorithm (see Theorem 4.2).

关键词： Cascade algorithm Cascade operator Refinable distribution Shift-invariant space Linear independent shifts Stable shifts Fractional Sobolev space

Comparing the Effectiveness of Coatings on Carbide andCermet Cutting Tool Inserts

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Journal of Materials Science & Technology 1995年第4期11卷 269-275页

作者： K.H. W.Seah M.Rahman and C.H.Lee (Dept. of Mech. & Prod. Eng., national university of singapore, 10 kent ridge Crescent, singapore 0511 T.N.Goh (Dept. of Ind. & Sys. Eng., national university of singapore, 10 kent ridge Crescent, singapore 0511) national Univ of singapore Singapore

A series of metal cutting experiments was performed on a CNC lathe to evaluate the performance of various coatings on different tool substrates. The workpiece material was plain medium carbon steel and the cutting tool materials were carbide and cermet inserts coated with various single as well as multilayer coatings. Machining was done under various cutting conditions of speed and feed-rate, and for various durations of Cutting. The output parameters studied were the cutting forces (axial, radial and tangential), the surface roughness of the workpiece, as well as the tool wear (crater and flank wear). From these results, the performances of the various cutting inserts are evaluated and compared. Results show that cutting forces are significantly lower when using coated cermets than when using coated carbides although different coatings on the same substrate also result in different cutting forces. However, there is less difference in the surface roughness of the finished workpiece for the various coatings and substrates.

关键词： Tool Comparing the Effectiveness of Coatings on Carbide andCermet Cutting Tool Inserts

Outcomes after percutaneous coronary interventions in patients with chronic kidney disease

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Journal of Geriatric Cardiology 2005年第3期2卷 183-187页

作者： Tan Huay Cheem Cardiac Department Level 3 Main BuildingNational University Hospital5 Lower Kent Ridge RoadSingapore 119074Singapore

IntroductionChronic kidney disease (CKD) is a significant contributor to cardiovascular morbidity and *** with CKD are known to have a greater prevalence of cardiovascular disease than the general population,1 and patients with concurrent CKD and coronary artery disease (CAD) have greater mortality than patients without CKD.2-4 The rate of cardiovascular mortality is approximately 50%,five to 10 times higher than the general population.

关键词： CKD Outcomes after percutaneous coronary interventions in patients with chronic kidney disease

A THIRD-ORDER BOUSSINESQ MODEL APPLIED TO NONLINEAR EVOLUTION OF SHALLOW-WATER WAVES

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Journal of Hydrodynamics 2000年第2期12卷 107-126页

作者： Zhang Ying long CCM MINDEF, Department of Mech. and Prod. Eng., national university of singapore, 10 kent ridge Crescent, singapore 119260 Zhu Song ping Department of Mathematics, the university of Wollongong, Wollongong, NSW 2522, Australia Natl Univ of singapore Singapore Singapore

The conventional Boussinesq model is extended to the third order in dispersion and nonlinearity. The new equations are shown to possess better linear dispersion characteristics. For the evolution of periodic waves over a constant depth, the computed wave envelops are spatially aperiodic and skew. The model is then applied to the study of wave focusing by a topographical lens and the results are compared with Whalin′s (1971) experimental data as well as some previous results from the conventional Boussinesq model. Encouragingly, improved agreement with Whalin′s experimental data is found. [WT5”HZ]

关键词： shallow water waves nonlinearity evolution third order Boussinesq model