Structure

Özet
Matematiğin mimarlık dahil olmak üzere farklı disiplinlerle girdiği sıkı ilişki ve teknolojinin gün geçtikçe gelişmesiyle kullanım alanı artan bilgisayar destekli tasarım teknolojisi sayesinde tasarım sürecinde farklı matematiksel modellerin kullanılması mümkün olmuştur. Matematiksel modellerle strüktür tasarımı, geometri ve malzeme parametrelerini ön plana çıkarmıştır. 
Karmaşıklık kuramının sistemdeki dinamiklerin modellenmesi açısından strüktür tasarımındaki rolü önemlidir. Birbirinden farklı birçok parametrenin olması ve bunlar arasındaki ilişkilerin keşif süreci taşıyıcı sistemi tasarlanabilir bir sistem yapmıştır.  Geometri, bu sistemin formunu oluşturur ve ilk dikkat çeken parametredir. Yaratılan her form bir geometri içerir ve formun ayakta durabilmesi için de strüktür tasarımına ihtiyaç vardır. Mimarlıkta geometriyle birlikte malzeme, tasarımın dokusunun, biçiminin ve binanın görünümünün oluşmasında temel bileşenlerdendir.
Strüktür tasarımında en temel yöntem olan sonlu elemanlar analizi ışığında, arup optimizeri, dinamik rahatlama, evrimsel şekil optimizeri ve evrimsel strüktür optimizeri incelenmiştir. Bu analizler sonucu ortaya çıkan zincir eğrisi, bükülme, minimal yüzey ve nurbs modelleri araştırılmıştır. Arup optimizeri, tüm sistemde kendi kendini organize etmesini sağlayacak en uygun tekrar elemanlarını seçer ve bu elemanları tek tek analiz eder. Dinamik rahatlama, malzemenin yerçekimi ile kendiliğinden şekil almasını sağlayan topolojik şekildeki kemer yapının optimizasyonunu sağlar. Evrimsel şekil optimizeri ise serbest forma en uygun alanı seçmek için en az deplasman yaptıracak strüktürel eleman yerleşmesini analiz eder. Evrimsel strüktür optimizeri ise sistemde vektörel gerilimi azaltmaya yönelik analizler yapar.
Strüktür modellerinden zincir eğrisi modelinde zincir, yerçekimine karşı oluşan eğrinin formunu alır. Bükülme, malzemenin kırılma noktasının gelişen teknoloji ve yeni malzemelerle eşik değerinin artması sonucunda, eski kırılma noktasının bükülmesiyle oluşan formdur. Minimal yüzeyler, minimum yüzey-gerilim potansiyel enerjisine sahip ve alan olarak da minimum olan formlardır. Nurbs ise üniform olmayan çizgiler eğrisidir ve bu eğriler, bir strüktür modelinde geometrinin haritalamasını yaparak serbest form yapıların strüktüre referans olabilecek olası çizgi ve yüzey ilşikilerinin hesaplanmasında kullanılırlar.
Matematiğin bir model oluşturduğu bu strüktür sistemlerinde, bilgisayar ortamında oluşan simülasyon, geçmişin sıkıcı ve anlaması zor olan hesaplamalarını geride bırakıp mimar ve mühendislere ortak olarak kullanabilecekleri bir ara yüz oluşturmuştur.

          Anahtar Kelimeler: Strüktür Tasarımı, Karmaşıklık Kuramı, Optimizasyon, Geometri, Kendi kendini Organize Etme, Topoloji

Kendi evini inşa etmek, büyülü ve çekici bir çağrı.

Peki gerçekten mümkün mü? Çok yakın bir tarihe kadar, hepimiz yaşayacağımız evi kendi ellerimizle ve köy imecesi ile yapıyorduk; Çölde, kutuplarda, dağ başları, nehir kenarlarında ya da çok uzak adalarda. Bütün insanlığın coğrafyalarına özel tasarımları ve nesilden nesile aktardıkları bir bilgelikleri vardı. Taş seçimiden, ağaçların kesileceği mevsim hatta ay döngüsüne kadar, şimdi bakıldığında insanı hayrete düşüren bir teknik ve tasarımla. Üstelik bu yapılar binlerce yıla meydan okuyor. Betonun altmış yıllık ömrü, bunları sadece güldürüyor.

İster kendi elleriniz ve belirli bir dayanışma ağı içinde evinizi yapmaya karar verdiniz, isterseniz bir usta ile anlaşıp işe koyuldunuz. Gözünüz kör, kulağınız sağır ve elleriniz bağlı olmasın. Artık kendi evini, seçtiği malzemeden, iç tasarıma kadar profesyonellerin insafına bırakmaya razı olmayan bir bakış açısı egemen oluyor. Bunun Türkiye’deki örnekleri azımsanmayacak kadar arttı.  Hem de ortaya çıkan yapılar, parmak ısırtıyor. Malzeme ile iklim arasındaki denge, araziye oturuş, deneysel çalışmalara verilen değer ve en önemlisi insanı içinde iyi hissettiren evler, hepsi mümkün.

Melih Aşanlı geleneksel sanatlar bilgilerinin üzerine, uzun yıllar çalıştığı restorasyon ve heykel tekniklerini de ekleyerek, kendisi gibi kırsala yerleşen veya yerleşmeye niyetli gönüllüler için muhteşem bir rehber kitap hazırladı. Arazi, toprak ve arazinin neresine evinizi oturtacağınızdan başlayarak, malzemeleri sınıflandırarak, temelden çatıya kadar evinizi inşa etmenizi yahut ustaları yönlendirmenizi sağlayacak kitabıyla hayranlık uyandırıyor. Melih Aşanlı belki de anlatmak istediklerinin özünü şöyle özetliyor;

“Suyun, toprağın, taşın, ağacın doğasını idrak etmek, algılamak en gerekli ilkeler. Malzemelere hükmetmeye çalışmadan da, sadece uyum sağlayarak ihtiyaçlarımızı karşılayabileceğimiz aslında eski olan güncel bir önerme ile ne isterseniz yapmakta özgürsünüz.”

Aslında bütün mesele de özgür olmak değil mi ?

According to the results of the Russian Finance Ministry assessment of the quality of
financial management of the managers of the federal budget, including process and
outcome indicators of financial activity as part of the state programs « Education
Development », « Science and Technology Development», the Ministry of Education and
Science of the Russian Federation in 2017 occupied the 26th place.
The relatively low financial and managerial statements of the Ministry of Education
and Science of the Russian Federation activity concerning government program funding
are caused by deficiencies in methods and tools for managing budget expenditures, and
it is proved by Russian Audit Chamber’s findings concerning the ineffectiveness of
financial expenditures in the «5-100» project.
In this way the relevance of the research theme is due to need for theoretical
development of the conceptual construct, modifying the model of organizational and
financial clearing for subsidizing government programs, adapting the algorithm for
applying social bonds to the education and science sectors of the Russian Federation,
justifying new methodological approaches and practical recommendations for developing
the system for financing government programs in the domain of education and science.

Anionic s complexes, also referred to as "Jackson-Meisenheimer" or "Meisenheimer" complexes, are key intermediates in the S N Ar mechanism of aromatic nucleophilic substitution reactions [Eq. (1)]. They are formed by the covalent addition of nucleophiles (Nu À ) to aromatic substrates bearing electron-withdrawing substituents (X) and have been characterized as stable or transient species by X-ray crystallography, NMR, and UV/Vis spectroscopy in condensed phases. As compared with the wealth of kinetic and thermodynamic studies on Meisenheimer complexes in solution, relatively few studies are concerned with their gas-phase chemistry. [3] In a recent report, the exceedingly fast reaction of fluoride ion with nitrobenzene was ascribed to a potentialenergy profile where the anionic ipso complex is a transition state rather than a stable species lying in a local energy minimum. A transition towards an energy profile displaying an anionic s complex intermediate is predicted by DFT calculations, as the para position with respect to the NO 2 leaving group (Y = NO 2 ) is substituted by an electron-withdrawing group. Gas-phase thermochemical data for the equilibria involving the addition of anions to substituted benzenes have been obtained by high-pressure mass spec-trometry, thereby providing information on the stabilities of the complexes though not directly on their structures. [6] Indeed, depending on the nature of the substituents on the benzene ring and the nature of Nu À , various stable structures can occur and structural assignments have relied largely on calculations. [6][7] The structural elucidation of prototypical Meisenheimer complexes in the gas phase is reported herein. To this end, a spectroscopic methodology is applied that is based on the coupling of the radiation output of an IR free-electron laser (FEL) at the CLIO (Centre Laser Infrarouge dOrsay) European facility with a Paul-type ion-trap mass spectrometer, thus exploiting the potential emerging from the combination of mass spectrometry with an IR FEL radiation source. [9] The IR features of a gaseous ion may be disclosed in the IR multiphoton dissociation (IRMPD) spectrum, which reports the resonance-enhanced photofragmentation process following multiple-photon absorption in correspondence with the IR active modes of the sampled species. Among the several recent achievements, IRMPD spectra have been reported for few inorganic negative ions, including complexes of halide ions, iron carbonyl clusters, and vanadium oxide cluster anions. When a basic methanol solution of 1,3,5-trinitrobenzene (TNB) is subjected to electrospray ionization (ESI) in the negative-ion mode, the adduct ion incorporating the anion of the solvent, [CH 3 OC 6 H 3 (NO 2 ) 3 ] À , is the major ionic species observed. The structural assay of the so-formed species is gained by IRMPD spectroscopy, whereby the ion is isolated in the ion trap and allowed to interact with the IR FEL radiation. A wavelength-dependent dissociation process leads to a major product ion formally corresponding to deprotonated TNB [Eq. (2 a)], implying loss of a methanol molecule. These products are thermodynamically favored with respect to the alkoxide ion and neutral TNB pair, owing to the higher acidity of nitrobenzene relative to primary alcohols. A second, minor dissociation pathway [Eq. (2 b)] occurs by formal loss of neutral methyl nitrite, leading to 2,4dinitrophenoxide as the likely product ion in a process involving substantial bonding rearrangement.

Calculating protein–protein interaction energies is crucial for understanding protein–protein associations. On the basis of the methodology of mean-field potential, we have developed an empirical approach to estimate binding free energy for protein–protein interactions. This knowledge-based approach has been used to derive distance-dependent free energies of protein complexes from a nonredundant training set in the Protein Data Bank (PDB), with a careful treatment of homology. We calculate atom pair potentials for 16 pair interactions, which can reflect the importance of hydrophobic interactions and specific hydrogen-bonding interactions. The derived potentials for hydrogen-bonding interactions show a valley of favorable interactions at a distance of ≈3 Å, corresponding to that of an established hydrogen bond. For the test set of 28 protein complexes, the calculated energies have a correlation coefficient of 0.75 compared with experimental binding free energies. The performance of the method in ranking the binding energies of different protein–protein complexes shows that the energy estimation can be applied to value binding free energies for protein–protein associations. Proteins 2002;46:190–196. © 2001 Wiley-Liss, Inc.

N-sulfinyltrifluoromethanesulfonamide was found to react with diisopropyl-and dicyclohexylcarbodiimides with the formation of N-trifluoromethanesulfonyl-2,4-dialkyl-1,2,4-thiadiazetidin-3-imine 1-oxides. The mechanism includes the [2p + 2p] cycloaddition resulting in 2-trifluoromethanesulfonyl-3-alkylimino-4-alkyl-1,2,4-thiadiazetidine 1-oxides, the ring opening of the latter, rotation about the C-N bond and the ring closure to the final products.

Transaldolase (Tal) is involved in the central carbon metabolism, i.e. the non-oxidative pentose phosphate pathway, and is therefore a ubiquitous enzyme. However, Tals show a low degree in sequence identity and vary in length within the enzyme family which previously led to the definition of five subfamilies. We wondered how this variation is conserved in structure and function. To answer this question we characterised and compared the Tals from Bacillus subtilis, Corynebacterium glutamicum and Escherichia coli, each belonging to a different subfamily, with respect to their biochemical properties and structures. The overall structure of the Tal domain, a (b ⁄ a) 8 -barrel fold, is well conserved between the different subfamilies but the enzymes show different degrees of oligomerisation (monomer, dimer and decamer). The substrate specificity of the three enzymes investigated is quite similar which is reflected in the conservation of the active site, the phosphate binding site as well as the position of a catalytically important water molecule. All decameric enzymes characterised so far appear to be heat stable no matter whether they originate from a mesophilic or thermophilic organism. Hence, the thermostability might be due to the structural properties, i.e. tight packing, of these enzymes.

Aromatic amines represent one of the most important classes of industrial and environmental chemicals: many of them have been reported to be powerful carcinogens and mutagens, and/or hemotoxicants. Their toxicity has been studied also with quantitative structure-activity relationship (QSAR) methods: these studies are potentially suitable for investigating mechanisms of action and for estimating the toxicity of compounds lacking experimental determinations. In this paper, we first summarized the QSAR models for the rodent carcinogenicity of the aromatic amines. The gradation of potency of the carcinogenic amines depended firstly on their hydrophobicity, and secondly on electronic (reactivity, propensity to be metabolically transformed) and steric properties. On the contrary, the difference between carcinogenic and non-carcinogenic aromatic amines depended mainly on electronic and steric properties. These QSARs can be used directly for estimating the carcinogenicity of aromatic amines. A two-step prediction is possible: (1) estimation of yes/no activity; (2) if the answer from step 1 is yes, then prediction of the degree of potency. The QSARs for rodent carcinogenicity were put in a wider context by comparing them with those for: (a) Salmonella mutagenicity; (b) general toxicity; (c) enzymatic reactions; (d) physical-chemical reactions. This comparative QSAR exercise generated a coherent global picture of the action mechanisms of the aromatic amines. The QSARs for carcinogenicity were similar to those for Salmonella mutagenicity, thus pointing to a similar mechanism of action. On the contrary, the general toxicity QSARs (both in vitro and in vivo systems) were mostly based on hydrophobicity, pointing to an aspecific mechanism of action much simpler than that for carcinogenicity and mutagenicity. The oxidation of the amines (first step in the main metabolic pathway leading to carcinogenic and mutagenic species) had identical QSARs in both enzymatic and physical-chemical systems, thus providing evidence for the link between simple chemical reactions and those in biological systems. The results show that it is possible to generate mechanistically and statistically sound QSAR models for rodent carcinogenicity, and indirectly that the rodent bioassay is a reliable source of good quality data.

The structure of copper iron pyrophosphate catalysts prepared with various atomic ratios of metals and different pretreatment conditions was studied by using XRD, FT-IR, DR UV-vis and H 2 -TPR techniques. The preparation methods modify the phase composition, oxidation state and reducibility of the patterns. The catalytic properties in the selective oxidation of methane to formaldehyde and methanol were examined in both, pulse and flow reactors, using O 2 and/or N 2 O oxidizing agents. The oxidants used impact the onset of methane conversion, the primary oxidation products formation and the methane conversion. The highest single-pass yield of useful oxygenates (1.8%) was achieved with N 2 O over the Cu/Fe ∼ = 1:2 pyrophosphate catalyst which consists mainly of the crystalline Fe II Fe III 2 (P 2 O 7 ) 2 and copper containing nanodomains. Enhanced interaction and cooperation between these phases leading to a synergic effect of Cu and Fe has been emphasized. The Cu II and Fe III species of the above structure can be reduced more easily but at similar temperatures than those in the crystalline CuFe 2 (P 2 O 7 ) 2 . Pulse reaction studies indicate that the lattice oxygen of the catalyst could react with methane molecules producing formaldehyde and methanol and replenishment of the lattice oxygen by N 2 O takes place rather readily and rapidly. The nature of active species, methane conversion and oxygenates selectivity remained almost unchanged during the time on stream.

Background-The anisotropy of cardiac tissue is a key determinant of 3D electric propagation and the stability of activation wave fronts in the heart. The electric properties of ventricular myocardium are widely assumed to be axially anisotropic, with activation propagating most rapidly in the myofiber direction and at uniform velocity transverse to this. We present new experimental evidence that contradicts this view. Methods and Results-For the first time, high-density intramural electric mapping (325 electrodes at Ϸ4ϫ4ϫ1-mm spacing) from pig left ventricular tissue was used to reconstruct 3D paced activation surfaces projected directly onto 3D tissue structure imaged throughout the same left ventricular volume. These data from 5 hearts demonstrate that ventricular tissue is electrically orthotropic with 3 distinct propagation directions that coincide with local microstructural axes defined by the laminar arrangement of ventricular myocytes. The maximum conduction velocity of 0.67Ϯ0.019 ms Ϫ1 was aligned with the myofiber axis. However, transverse to this, the maximum conduction velocity was 0.30Ϯ0.010 ms Ϫ1 , parallel to the myocyte layers and 0.17Ϯ0.004 ms Ϫ1 normal to them. These orthotropic conduction velocities give rise to preferential activation pathways across the left ventricular free wall that are not captured by structurally detailed computer models, which incorporate axially anisotropic electric properties. Conclusions-Our findings suggest that current views on uniform side-to-side electric coupling in the heart need to be revised. In particular, nonuniform laminar myocardial architecture and associated electric orthotropy should be included in future models of initiation and maintenance of ventricular arrhythmia. (Circ Arrhythmia Electrophysiol. 2009;2:433-440.)

Antigen recognition by ab T lymphocytes is mediated via the multisubunit TCR complex consisting of invariant CD3g,d,o and z chains associated with clonotypic TCRa and b molecules. Charged amino acids located centrally within the TCRa transmembrane region are necessary and sufficient for assembly with the CD3do heterodimer. Previously, we have shown that deletion of 6-12 amino acids from the carboxy terminus of the TCRa-chain dramatically abrogates surface TCR expression, suggesting that the distal portion of the TCRa transmembrane region contains information that regulates the assembly and/or intracellular transport of TCR complexes. We have examined in more detail the molecular basis for reduced TCR expression in T cells bearing truncated TCRa chains. We found that in contrast to wild-type (wt), variant TCRa proteins missing the last nine C-terminal amino acids did not associate with core CD3g,d,o chains and were not assembled into disulphide-linked ab heterodimers. The stability of newly synthesised wt and variant TCRa molecules was similar, showing that the abrogated surface TCR expression was not a consequence of impaired protein survival. Nevertheless, truncated TCRa chains still assembled with the chaperon protein calnexin in the endoplasmic reticulum, indicating that the distal portion of the TCRa transmembrane region is not essential for calnexin interaction. These data document a role for the distal portion of the TCRa transmembrane region in the assembly of TCR complexes and provide a molecular basis for reduced TCR expression in cells bearing truncated TCRa chains.

The isothermal ternary phase diagram for the 1-dodecylpyridinium bromide/dodecane/water system was determined at 40°C by 2 H NMR and polarizing microscopy methods. Two liquid crystalline phases, a large cubic area and a normal hexagonal phase, and one isotropic normal micellar solution phase were characterized, and their ranges of existence were determined. The micelles were found to be probably small and spherical at lower concentrations of surfactant, and were found to grow at higher concentrations and on addition of oil. The two-phase areas, L 1 ؉ H I and H I ؉ I, are both very narrow. The comparatively large cubic area, containing 43-63 wt% surfactant and 3-10 wt% dodecane, is probably consistent of more than one structure. SAXS experiments indicate two different structures built of discrete micellar aggregates.

Background: Feedback inhibition of biosynthetic threonine deaminase (TD) from Escherichia coli provided one of the earliest examples of protein-based metabolic regulation. Isoleucine, the pathway end-product, and valine, the product of a parallel pathway, serve as allosteric inhibitor and activator, respectively. This enzyme is thus a useful model system for studying the structural basis of allosteric control mechanisms.

By allowing the estimation of forest structural and biophysical characteristics at different temporal and spatial scales, remote sensing may contribute to our understanding and monitoring of planted forests. Here, we studied 9-year time-series of the Normalized Difference Vegetation Index (NDVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) on a network of 16 stands in fast-growing Eucalyptus plantations in São Paulo State, Brazil. We aimed to examine the relationships between NDVI time-series spanning entire rotations and stand structural characteristics (volume, dominant height, mean annual increment) in these simple forest ecosystems. Our second objective was to examine spatial and temporal variations of light use efficiency for wood production, by comparing time-series of Absorbed Photosynthetically Active Radiation (APAR) with inventory data.

Arrangements of cationic starches hydrophobized by acetylation (CS-acet) deposited from aqueous electrolyte solutions onto hydrophilized and hydrophobized silica surfaces were investigated by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The influence of electrolyte composition, acetylation degree of cationic starch (DS ACET ), and deposition method was examined. On a hydrophobic substrate, CS-acet formed an open film with structure strongly dependent on DS ACET and electrolyte composition of the solution. On a hydrophilic substrate, acetylation increased the hydrophobicity of the film when the starch was deposited by adsorbing. When deposition was made by spin coating, i.e., the CS-acet was forced onto the substrate, the hydrophobic tuning by acetylation was lost. The films deposited by spin coating were thicker and considerably rougher than those deposited by adsorbing.

Since the cloning of Aequorea victoria green fluorescent protein (GFP) in 1992, a family of known GFP-like proteins has been growing rapidly. Today, it includes more than a hundred proteins with different spectral characteristics cloned from Cnidaria species. For some of these proteins, crystal structures have been solved, showing diversity in chromophore modifications and conformational states. However, we are still far from a complete understanding of the origin, functions and evolution of the GFP family. Novel proteins of the family were recently cloned from evolutionarily distant marine Copepoda species, phylum Arthropoda, demonstrating an extremely rapid generation of fluorescent signal. Here, we have generated a non-aggregating mutant of Copepoda fluorescent protein and solved its high-resolution crystal structure. It was found that the protein b-barrel contains a pore, leading to the chromophore. Using site-directed mutagenesis, we showed that this feature is critical for the fast maturation of the chromophore.

We have employed computer-aided furnace design and process simulation to optimize the conditions under which single-walled carbon nanotubes (SWCNTs) may be grown in high yields on 4 in. wafers for electronic device applications. Hydrokinetic simulations were performed to obtain optimized furnace structures and process conditions in terms of gas flow, temperature, and gas speed. Shower head structures and a flow isolation barrier were installed in an experimental 6 in. furnace, as suggested by the hydrokinetic simulations. To ensure clean surfaces and uniform catalyst islands, catalyst patterns were lifted off using Au films or polydimethylsiloxane. Photolithography was used to fabricate field-effect transistors with SWCNTs grown on 4 in. wafer substrates. The total yield of the nanotube devices increased from 30.5% to 96.4% after optimization.

The work focused on the penultimate enzyme, prothrombin, in the coagulation cascade. Prothrombin was purified and characterized from ostrich plasma. The results obtained contribute to a better understanding of blood coagulation in the ostrich and the evolution of prothrombin and the coagulation cascade. Prothrombin was purified from ostrich plasma by barium chloride precipitation, ammonium sulfate fractionation, and DEAE-cellulose and Cu 2 + -chelate Sepharose chromatography. Ostrich prothrombin exhibited a M r of 72 800 and a pI of 6.9 using SDS-PAGE and PAG-isoelectrofocusing, respectively. The N-terminal sequence of ostrich prothrombin showed 78 and 87% identity with human and bovine, respectively. The cDNA was isolated from ostrich liver and the predicted amino acid sequence compared with those from other species. Ostrich prothrombin shares sequence identity with chicken (84%), human (60%), bovine (59%), rat (60%), mouse (59%) and hagfish (50%) prothrombin, suggesting a common function of prothrombin in these vertebrates. Amino acid sequence identities indicate that the thrombin b-chain (62%) and the propeptide-Gla (75%) domains are the regions most constrained for the common functions of vertebrate prothrombins. Ostrich prothrombin, therefore, shows similarity in structure to other vertebrate prothrombins.

The impact of sugar (17.6-31.2%) and fat (8.7-15.8%) levels on cookie structure was studied. Cookie diameter increased and its height decreased with increasing sugar or fat levels. X-ray microfocus computed tomography porosities and cell sizes increased with fat level, but cell size distribution, cell wall thickness and distribution were not affected by fat level, indicating that fat primarily incorporates air. In contrast, the sugar level influenced porosity, cell size, cell wall thickness and their relative distributions. Thus, the sucrose level, probably by affecting dough viscosity during baking, largely influences the baked cookie structure. Cell and cell wall anisotropy measurements indicated that the inner orientation of cells and cell walls probably depends on the horizontal spread behaviour, rather than on the maximum cookie height and collapse. Finally, the surface cracking pattern was determined by sugar level, rather than by structural collapse at the end of baking.

The EF-hand family is a large set of Ca 2+ -binding proteins that contain characteristic helix-loop-helix binding motifs that are highly conserved in sequence. Members of this family include parvalbumin and many prominent regulatory proteins such as calmodulin and troponin C. EF-hand proteins are involved in a variety of physiological processes including cell-cycle regulation, second messenger production, muscle contraction, microtubule organization and vision.

Two novel zeolites MCM-58 and MCM-68 with 12-ring channels and containing the cages in the structure were investigated with respect to their acidic properties and compared with other two 12-ring zeolites, namely Beta and ZSM-12. The main objective was to characterize the accessibility and acid strength of Lewis and Brønsted sites using FTIR spectroscopy. Pyridine adsorption allowed for quantification of Brønsted and Lewis acid centres and pointed out that while in the structure of MCM-58 nearly all Al atoms form acidic SiAOHAAl bridges, only about half of Al is a source of the Brønsted acidity in MCM-68. The special attention was devoted to the origin and location of the hydrogen-bonded OH groups in the MCM-58 zeolite. The frequency lowering is caused by the across-the-ring interaction with the oxygen atom and not by the interaction with the nearby OH groups, as proved by high temperature activation and deuteration experiments. The location of the 3485 cm À1 OH groups in the five member ring was proposed. Carbon monoxide adsorption allowed proposing the location of the residual K + cations in the main channels of MCM-58 and in the 6 10 4 6 cages in MCM-68.

Highlights d AnchorDock allows flexible and completely blind highresolution docking of peptides d AnchorDock search is directed to the most relevant parts of the conformational space d AnchorDock supports a recognition model that is driven by local structural elements

There has been substantial academic interest surrounding innovation, change management, and the individual attributes that permit and promote learning, organisational change and innovative behaviour. This research uses a psychometric tool known as the Instinctive Drives System® to measure preferred working styles in 3,943 employees from a range of international companies. The employees were then classified into three groups (Engineers, Operators and Executives) following Schein's (1996) classification of occupational subcultures. This study reveals significant differences between the occupational subcultures, suggesting that executives are more inclined towards variety, flexibility and change rather than routine and structure. In contrast, operators and engineers demonstrated preferences for logic and certainty. These results have a range of implications, for researchers and practitioners. Researchers can extend the results of this study, and further explore the differences found between executives and managers from different subcultures. Practitioners may use the results to initiate change to integrate preferred working styles.

a b s t r a c t Nanometric inorganic pigments are widely used as fillers for hybrid composite materials. However, these nanometric powders are hydrophilic in nature and their surface must be functionalized before use. In this work, titanium dioxide (TiO 2 ) nanoparticles were coated using silane coupling agents with alkyl functionality. A supercritical carbon dioxide (scCO 2 ) method was used for surface silanization. Five alkylalkoxysilanes with different alkyl chain length and structure were studied: methyltrimethoxy, isobutyltriethoxy, octyltriethoxy, octyldimethylmethoxy and octadecyltrimethoxysilane. The microstructure and thermal stability of deposited monolayers were characterized using thermogravimetric analysis, ATR-IR spectroscopy, transmission electron microscopy, wettability characterization and low-temperature N 2 adsorption/desorption analysis. The use of scCO 2 as a solvent provided an effective approach to functionalize individual inorganic nanoparticles due to the enhanced diffusivity of the solution molecules in the aggregates interparticle voids. The trifunctional silanes employed here yielded surfaces with better thermal stabilities and greater hydrophobicities than the used monofunctional silane.

Binary blend films from lactide-rich poly (D-lactide-co-glycolide) (PDLG) and poly ( Llactide-co-glycolide) (PLLG ) were obtained by casting methylene chloride solutions of the two mixed copolymers with different D-and L-lactide contents ( X D I and X L I ) ,

The structure and force field of pyridine-3-carboxamide (nicotinamide)-d 0 and-d 2 have been studied by IR spectra, ab initio and density functional calculations. According to the energy analysis, the E-conformer is more stable than the Zone. This result is in agreement with the correlation analysis performed (experimental vs theoretical IR frequencies), that indicates the same conformer is prevalent in CHCl 3 /CDCl 3 solutions, as well as in the solid state. Both ab initio and DFT force field calculations give good descriptions of the IR spectra of nicotinamided 0 and-d 2 studied, and fairly good ones for the corresponding isotopic shifts. The theoretical bond lengths and angles are in excellent agreement with those determined experimentally by electron and neutron diffractions. According to the calculations, the carboxamide group holds a negative electric charge and the Mulliken charge transfer between it and the b-pyridyl ring is 0.30 e K .

Just as law has survived Legal Realism and Critical Legal Studies, just as philosophy has survived the deconstruction of Derrida and Foucault, cricket has survived Bodyline and all the other contradictions of the game. Like all other games, cricket involves a tension between the game as 'game' and the 'game' as an embodiment of cultural lessons and broader messages. (Fraser 1993: 272). Body-line was not an incident, it was not an accident, it was not a temporary aberration. It was the violence and ferocity of our age expressing itself in cricket. (James 1963: 188). More recently, the game has erupted with issues of cheating and bad sportsmanship which have encompassed libel actions between International players, and the banning (but subsequent reinstatement) of the gifted Pakistani player Salim Malik [1]. Contemporaneously, allegations surfaced in the English County Championship with relation to match

La notion d'« appareils » insiste sur le fait qu'une époque se constitue à partir de l'articulation singulière d'une loi, d'un dispositif technique et d'un support, qui tour à tour qualifie, manipule (techniquement) et enregistre, comme trace, « l'événement ». L'appareil, c'est : ce qui met en rapport la singularité et la collectivité avec la loi, selon des normes de légitimité » […] « La loi, c'est ce qui ouvre le matériau (le corps) à autre chose que lui : l'événement 1. Diagrammes et temporalité architecturale : la loi des « appareils »

The information on population structure of Acanthaster planci in Bunaken National Park (BNP) is urgent to be presented in order to be considered in decision making especially on coral reef management in BNP. The objectives of  this study was to examine the  population structure of A. planci, represented by the diameter and weight, number of arms, while the density, distribution and types of coral predation by reef animals in the Southern part of Bunaken Island also observed. Data were collected at the three locations namely, front reef flat (FRF), middle reef flat (MRF) and back reef flat (BRF) with total coverage area of ​​100 x 50 meters. Sixty two individuals (41 at night and 21 at day time) were found with a body diameter ranging between 14 – 28 cm, whereas body weight ranged from 80 – 700 gr, with the number of arms between 9 until 17. The density of A. planci during day time was 0.0042 ind/m2, while the night time was 0.0082 ind/m2, moreover the animal is generally spread aggr...

According to literature data, high-pressure homogenisation of starch paste in the optimum conditions gives a product of digestibility reduced by 50%. This product has been analysed from the point of view of its resistance to enzyme activity. Results obtained by X-ray diffraction, scanning electron microscopy, optical microscopy and measurements of surface activity prove that reduction in the product digestibility is not related to changes in its crystalline structure and morphology of its particles. The product of high-pressure homogenisation of the paste is also found to be characterised by very slow kinetics of wetting. In comparison to the native starch, the aqueous solutions of the product of homogenisation show significantly different surface activity and different mode of iodine complexation.

The paper attempts to provide an updated and holistic description of the research ethics system in Latvia and discuses the problems in its structure and functioning. It is based on the data gathered in an empirical study of RECs in Central and Eastern Europe in 2008 and it is structured according to the integrated framework proposed by Hyder et al. First a short outline of the historical development of the ethics review system in the 1990s is given, then the issues of general social, political and economic background and the resultant enabling conditions, as well as the national and regional strategy of ethical review are reviewed. Next, the discussion turns to institutional commitment, the factors influencing the quality of review, and ethically relevant aspects of investigators’ behavior. The main conclusion is that current developmental conditions are not too favorable for research ethics review; despite the overall progress, several crucial enabling conditions are not in place yet.

This paper describes the planning and control procedures observed to operate in a medium-sized British company producing and marketing animal foods and related products for agricultural markets, and relates these to the emergence of corporate strategies. It focuses upon the role of management in this process and relies upon the accounts given by managers and observation of their behaviour to accomplish this. Much of the description is presented using managers' own words. Rhenman's framework is used to set the observations in a wider theoretical context.

The concepts``habit'' and``habitus,'' having almost disappeared from the sociological lexicon during the earlier part of the postwar period, 1 are currently enjoying renewed interest in the social sciences. This is due, in large part, to the work of Pierre Bourdieu. 2 Bourdieu uses the concept of the habitus to steer a way through some of the key theoretical polarities and problems of contemporary sociological theory and, on that basis, is able to construct a very powerful and persuasive theory of practice. His work draws out the signi¢cance and relevance of the concept of habit for sociological purposes and in doing so makes a very appealing case for a habit or disposition based theory of agency. Notwithstanding this, however, Bourdieu's formulation and use of the concept of the habitus does raise a number of di¤culties. Furthermore, there is more potential for an elaboration and deepening of this concept than his work to date has achieved. In this article, I seek both to identify these weaknesses and shortcomings and to consider ways in which we might fruitfully respond to them. In particular, I suggest that a return to the phenomenological literature on habit and the habitus, which Bourdieu himself has certainly drawn from, provides a useful ¢rst step for developing and strengthening this central sociological concept. This is not intended as a phenomenological critique of Bourdieu, a call to replace his conception of habit with a phenomenological one nor a call for a full scale``marriage'' of phenomenology with Bourdieu's sociology. It is my view that Bourdieu o¡ers the most persuasive and exciting framework in contemporary sociology and I am simply re£ecting upon a number of ways in which that framework can be elaborated and deepened. For this reason, I make no e¡ort to outline the phenomenological project or consider its broader relevance or disagreements with the work of Bourdieu. My interest in phenomenology, for the purposes of this article, is restricted purely to the insights it o¡ers on the nature of habit. It is for this same

This work gives estimated values of the velocity correlation coefficients VCCs for ternary electrolyte solutions (the system may have a tracer ion as one of the components), utilizing available measured transport coefficients. The VCCs originate from linear response theory and give a deeper insight into the microdynamic structure of complex ionic solutions. By assuming Onsager's relation to be valid, ten sets of velocity correlation coefficients were calculated for a ternary system and were used to calculate the VCCs for 134 Cs + ion (present in trace amount) transport in aqueous solutions of CsCl and KCl at 25 • C. Keywords Velocity correlation coefficients • Cs + ion transport • Diffusion coefficients • Sliding cell method • Radioactive tracer technique • Aqueous CsCl solution • Aqueous KCl solution

Spider venoms are complex mixtures of neurotoxic peptides, proteins and low molecular mass organic molecules. Their neurotoxic activity is due to the interaction of the venom components with cellular receptors, in particular ion channels. Spider venoms have proven to be a rich source of highly specific peptide ligands for selected subtypes of potassium, sodium and calcium channels, and these toxins have been used to elucidate the structure and physiological roles of the channels in excitable and non-excitable cells. Spider peptides show great variability in their pharmacological activity and primary structure but relative homogeneity in their secondary structure. Following diverse molecular evolution mechanisms, and in particular selective hypermutation, short spider peptides appear to have functionally diversified while retaining a conserved molecular scaffold. This paper reviews the composition and pharmacology of spider venoms with emphasis on polypeptide toxin structure, mode of action and molecular evolution. © 2000 Société française de biochimie et biologie moléculaire / Éditions scientifiques et médicales Elsevier SAS spiders / neurotoxins / peptides / ion channels / structure / pharmacology * Correspondence and reprints.

Background: Non-Watson-Crick base pair associations contribute significantly to the stabilization of RNA tertiary structure. The conformation adopted by such pairs appears to be a function of both the sequence and the secondary structure of the RNA molecule. GA mispairs adopt G(anti)A(anti) configurations in some circumstances, such as the ends of helical regions of rRNAs, but in other circumstances probably adopt an unusual configuration in which the inter-base hydrogen bonds involve functional groups from other bases. We investigated the structure of GA pairs in a synthetic RNA dodecamer, r(CGCGAAUUAGCG), which forms a duplex containing two such mismatches. Results: The structure of the RNA duplex was determined by single crystal X-ray diffraction techniques to a resolution in the range 7.0-1.8A, and found to be an A-type helical structure with 10 Watson-Crick pairs and two GA mispairs. The mispairs adopt the G(anti) A(anti) conformation, held together by two obvious hydrogen bonds. Unlike analogous base pairs seen in a DNA duplex, they do not exhibit a high propeller twist and may therefore be further stabilized by weak, reverse, three-center hydrogen bonds. Conclusions: G(anti)A(anti) mispairs are held together by two hydrogen bonds between the 06 and N1 of guanine and the N6 and N1 of adenine. If the mispairs do not exhibit high propeller twist they may be further stabilized by inter-base reverse three-centre hydrogen bonds. These interactions, and other hydrogen bonds seen in our study, may be important in modelling the structure of RNA molecules and their interactions with other molecules.