艾哈迈德·阿德南·萨伊贡艺术中心,伊兹密尔,土耳其

<正>一座建筑的性能应当如何来衡量?除了通过统治当代建筑舆论的美学、技术以及经济价值来进行描述之外,我们还能够如何来阐释一座建筑,尤其是一座致力于庇护那些渴望展现自己的艺术家的建筑?有人会问成功的表演是如何实现的,表演者是如何进行伪装的、又是如何展现自己的?根据海德格尔的理论,当我们看不到钉子的时候,铁锤的表现才是成功的;钉子本身的出现通常表明出现了问题。     

The evolution of clinical periodontal therapy

Periodontal diseases are considered as old as the history of mankind, Magical, religious and herbal treatments were demonstrated in almost all of the early writings. However, methodical, carefully reasoned therapeutic approaches did not exist until the middle-ages and modern treatment with a scientific base and sophisticated instrumentation did not develop until the 18th century. Prior to the 1950s, diseases were mostly treated by root debridement and the extraction of the affected teeth. Until the 1970s, it was primarily the symptoms of periodontal diseases that were treated. The goal was radical elimination of the periodontal pocket (resective therapy). The means were gingivectomy, flap procedures and osseous surgery. The disadvantages were the massive sacrifice of periodontal tissues, lack of regeneration and clinically elongated teeth. These disadvantages, along with the realization of the importance of aetiologic agents, raised questions about the necessity of total pocket elimination, and the control of subgingival infection by a thorough scaling and root planing (nonsurgical therapy), with and without antibiotics, became a commonly used treatment during the 1980s. Comparative longitudinal studies, surgical versus nonsurgical, demonstrated that both surgical and nonsurgical therapy result in limited regeneration and healing with a long junctional epithelium. The most important aspects of today's modern concept of periodontal therapy are causal, regenerative, and specific for disease type and severity. Although the regeneration of the periodontium can be accomplished with the biological principles of guided tissue regeneration and graft materials, compared to conventional methods, the restoration of a completely normal periodontal status has not yet been achieved. We are about to reach our ultimate goals and presently, the more promising research directions for a substantial regeneration seems to lie in biological mediators. Although the future of periodontal therapy is bright, it is still of critical importance to have a preventive strategy to keep individuals healthy beforehand.     

Evidence for dinucleotide flipping by DNA photolyase

DNA photolyases repair pyrimidine dimers via a reaction in which light energy drives electron donation from a catalytic chromophore, FADH-, to the dimer. The crystal structure of Escherichia coli photolyase suggested that the pyrimidine dimer is flipped out of the DNA helix and into a cavity that leads from the surface of the enzyme to FADH-. We have tested this model using the Saccharomyces cerevisiae Phr1 photolyase which is >50% identical to E. coli photolyase over the region comprising the DNA binding domain. By using the bacterial photolyase as a starting point, we modeled the region encompassing amino acids 383-530 of the yeast enzyme. The model retained the cavity leading to FADH- as well as the band of positive electrostatic potential which defines the DNA binding surface. We found that alanine substitution mutations at sites within the cavity reduced both substrate binding and discrimination, providing direct support for the dinucleotide flip model. The roles of three residues predicted to interact with DNA flanking the dimer were also tested. Arg452 was found to be particularly critical to substrate binding, discrimination, and photolysis, suggesting a role in establishing or maintaining the dimer in the flipped state. A structural model for photolyase-dimer interaction is presented.     

A note on histamine levels in Turkish style fermented sausages

The histamine contents of Turkish style fermented sausages were determined on 46 samples of five different brands obtained from retail stores in Van in Turkey. Histamine was found in all samples in the range 19.64-87.47 mg/kg (mean 32.13 mg/kg). Histamine levels in the brands differed significantly (P<0.01). The results suggest that the histamine levels in the sausages were not hazardous in terms of public health although they may be a potential risk to sensitive individuals.     

The effect of sulphuric acid activation on the crystallinity,surface area,porosity, surface acidity,and bleaching power of a bentonite

The Hanç?l? (Keskin, Ankara, Turkey) bentonite was activated with H₂SO₄ by dry method at 97 °C for 6 h to obtain optimum parameters for imparting a maximum bleaching power towards soybean oil. The H₂SO₄ content in dry bentonite-acid mixture was changed between 0% and 70%. The natural and activated samples were examined by X-ray diffraction (XRD), N₂ adsorption–desorption, and n-butylamine adsorption (from the solution in cyclohexane). The specific surface area (S), specific micro–mesopore volume (V), mesopore size distribution (PSD), and surface acidity (n_m) of the samples were determined. The bleaching power (BP) of each sample for alkali-refined soybean oil was determined. The S, V, n_m, and BP increase after activation at various acid contents up to 40% H₂SO₄ without any considerable change in crystal structure of the smectite. The BP is controlled more by the PSD rather than other adsorptive properties of the bleaching earth. The optimum parameters for activation to obtain maximum bleaching power, are H₂SO₄% = 50–60, S = 250–230 m² g⁻¹, V = 0.46–0.47 cm³ g⁻¹, n_m = 9.0 × 10⁻⁴–8.4 × 10⁻⁴ mol g⁻¹ and PSD mainly distributed between 1.4 and 6.0 nm.     

Simulation analysis of lot streaming in job shops with transportation queue disciplines

In this paper we study a multi-product lot streaming problem in a stochastic job shop with equal and discrete sublots. The problem involves splitting order quantities of different products into different number of equal sublots (NES) and analyzing the effects of sublot-related transportation queue disciplines (TRQD) for different performance measures. Our simulation results show that some combination of TRQD and NES alternatives are appropriate for some performance measures. We also propose a simple heuristic to determine the NES of each product type to further improve the values of performance measures.