An electron microscopic study of quasicrystals in a quaternary alloy : Mg32(Al, Zn, Cu)49

The discovery of a solid exhibiting m 3 5 point group symmetry by Shechtman et. al. (l) in a rapidly solidified Al-14at%Mn alloy has activated intensive studies of a new class of solids, termed as quasicrystals (2). While the original discovery reported the existence of quasicrystals in AI-Mn. AI-Fe and AI-Cr alloys, subsequent work has revealed their existence in Mg-Zn-Al(3,4), Mg-A]-Cu(5), AI-Mn-Si(6) and Ti-Ni-V(7) alloys (Table l).

Proton NMR studies of dihalogenated phenyl benzamides: two-dimensional higher quantum methodologies

The scalar coupled proton NMR spectra of many organic molecules possessing more than one phenyl ring are generally complex due to degeneracy of transitions arising from the closely resonating protons, in addition to several short- and long- range couplings experienced by each proton. Analogous situations are generally encountered in derivatives of halogenated benzanilides. Extraction of information from such spectra is challenging and demands the differentiation of spectrum pertaining to each phenyl ring and the simplification of their spectral complexity. The present study employs the blend of independent spin system filtering and the spin-state selective detection of single quantum (SO) transitions by the two-dimensional multiple quantum (MQ) methodology in achieving this goal. The precise values of the scalar couplings of very small magnitudes have been derived by double quantum resolved experiments. The experiments also provide the relative signs of heteronuclear couplings. Studies on four isomers of dilhalogenated benzanilides are reported in this work.

High Resoulution Electron Microscopy of Chloritoid Minerals From Different Geological Melieu

Structural defects of three chloritoid minerals from distinet geologic melieu have been investigated by high resolution electron microscopy. X-ray powder and electron diffraction patterns indicate that the chloritoid from one geological source (A) is2M 1+2M2 monoclinic variant while those from another geological source (B) are 2M 2 monoclinic variants. In a typical one-dimensional lattice image of a crystal from sourceA, the 2M 2 matrix is broken by insertion of triclinic inter-growths. Another crystal with the 2M 2 matrix showed single, triple, quadruple and quintuple layers displaying an unusually high degree of disorder. Lattice images of 2M 2 monoclinic variants from sourceB yielded more homogeneous micrographs. The important finding from the present studies is that the chloritoid from sourceA is a severely disordered low-temperature intermediate phase in the conversion of the triclinic chloritoid to the high-temperature ordered monoclinic variants of sourceB. Severely disordered chloritoids, marking the beginning of low grade metamorphism, are generated as intermediates between the state of complete disordered arrangement towards the end of low grade metamorphism within the narrow stability range of 400°–500°C.

In planta localization and interactions of impatiens necrotic spot tospovirus proteins

Impatiens necrotic spot tospovirus (INSV) is a significant pathogen of ornamentals. The tripartite negative- and ambi-sense RNA genome encodes six proteins that are involved in cytoplasmic replication, movement, assembly, insect transmission and defence. To gain insight into the associations of these viral proteins, we determined their intracellular localization and interactions in living plant cells. Nucleotide sequences encoding the nucleoprotein N, non-structural proteins NSs and NSm, and glycoproteins Gn and Gc of a Kentucky isolate of INSV were amplified by RTPCR, cloned, sequenced and transiently expressed as fusions with autofluorescent proteins in leaf epidermal cells of Nicotiana benthamiana. All proteins accumulated at the cell periphery and co-localized with an endoplasmic reticulum marker. The Gc protein fusion also localized to the nucleus. N and NSm protein self-interactions and an NSm-N interaction were observed by using bimolecular fluorescence complementation. A tospovirus NSm homotypic interaction had not been reported previously.

A hypothesis on the role of hydroxyproline in stabilizing collagen structure

The possibility of hydroxyproline residues stabilizing the collagen triple-helical structure by the formation of additional hydrogen bonds through their γ-hydroxyl group has been studied from structural considerations. It is not possible for this hydroxyl group to form a direct hydrogen bond with a suitable group in a neighbouring chain of the triple-helical protofibril. However, in the modified one-bonded structure, which is stabilized by additional hydrogen bonds being formed through water molecules as intermediaries (put forward in 1968 by Ramachandran, G. N. and Chandrasekharan, R.), it is found that the γ-hydroxyl group of hydroxyproline can form a good hydrogen bond with the water oxygen as acceptor, the hydrogen bond length being 2.82 Å. It is proposed that, in addition to stabilizing the collagen triple-helical structure due to the stereochemical properties of the pyrrolidine ring, hydroxyproline gives added stability by the formation of an extra hydrogen bond. Experimental studies on the determination of shrinkage and denaturation temperatures of native collagen and its synthetic analogues, as a function of their hydroxyproline content, are being undertaken to test this hypothesis.

The mean geometry of the peptide unit from crystal structure data

The average dimensions of the peptide unit have been obtained from the data reported in recent crystal structure analyses of di- and tripeptides. The bond lengths and bond angles agree with those in common use, except for the bond angle C---N---H, which is about 4° less than the accepted value, and the angle C2α---N---H which is about 4° more. The angle τ (Cα) has a mean value of 114° for glycyl residues and 110° for non-glycyl residues. Attention is directed to these mean values as observed in crystal structures, as they are relevant for model building of peptide chain structures.

The non-planar peptide unit II. Comparison of theory with crystal structure datastar, open

The theoretical results derived in Part I (Ramachandran, G.N., Lakshminarayan, A.V. and Kolaskar, A.S. (1973) Biochim. Biophys. Acta 303, 8–13) that the three bonds of the peptide unit meeting at N can have a pyramidal structure is confirmed by an analysis of 14 published crystal structures of small peptides. It is shown that the dihedral angles θN and Δω are correlated, while θC, is small and is uncorrelated with Δω, showing that the non-planar distortion at C′ is generally small.

Theory of the non-planar peptide unitstar, open

By means of CNDO/2 calculations on N-methyl acetamide, it is shown that the state of minimum energy of the trans-peptide unit is a non-planar conformation, with the NH and NC2α bonds being significantly out of the plane formed by the atoms C1α, C′, O and N.

Conformation of the LL and LD hairpin bends with internal hydrogen bonds in proteins and peptides

The conformation of three linked peptide units having an internal 4 → 1 type of hydrogen bond has been studied in detail, and the low energy conformations are listed. These conformations all lead to the reversal of the chain direction, and may therefore be called as “hairpin bends” or “U-bends”. Since this bend can occur at the end of two chains hydrogen-bonded in the antiparallel β-conformation, it is also known as the “β-bend”. Two types of conformation are possible when the residues at the second and third Cα atoms are both of type L (the LL bend), while only one type is possible for the LD and the DL bend. The LL bend can also accommodate the sequences LG, GL, GG (G = glycine), while the LD bend can accommodate the sequences LG, GD and GG. The conformations for the sequences DD and DL are exact inverses (or mirror images) of those for the sequences LL and LD, respectively, and have dihedral angles (phi2, ψ2), (phi3, ψ3) of the same magnitudes, but of opposite signs as those for the former types, which are listed, along with the characteristics (length, angle and energy) of the hydrogen bonds. A comparison of the theoretical predictions with experimental data (from X-ray diffraction and NMR studies) on proteins and peptides, show reasonably good agreement. However, a systematic trend is observable in the experimental data, slightly deviating from theory, which indicates that some deformations occur in the shapes of the peptide units forming the bend, differing from that of the standard planar peptide unit.

Stabilization of the collagen structure by hydroxyproline residues

The molecular structure of collagen is now accepted to be based on a triple-stranded coiled-coil, in which the three strands are held together predominantly by hydrogen bonds. Recent experimental evidence has shown that the presence of hydroxyproline residues in the third position of the repeating tripeptide unit lends additional stability to the collagen structure. In this paper, we report a model structure, which is supported by these observations. In a model structure proposed earlier, there are two hydrogen bonds per tripeptide unit, one of which is a direct interchain hydrogen bond, while the second hydrogen bond can be formedvia a water molecule. It has now been shown that the same water molecule can also form a hydrogen bond with the oxygen of theγ-hydroxyl group of hydroxyproline in the third position in the sequence (Gly-R2-R3). This hydroxyl group can also take part in an inter-triple-helix hydrogen bond. Our studies thus show the role played by hydroxyproline residues in the structure and stability of collagen.

The Fashion Studies Book

The Fashion Book is an exciting, readable and comprehensive, all-in-one resource for students of fashion across the English-speaking world. It is designed as an introduction to fashion studies that can be used in a range of fashion courses from fashion studies degrees to fashion modules, and majors in disciplines including cultural studies, cultural sociology, cultural geography, communications and media, anthropology and cultural history. The book will present current writings and research on major topics debates in fashion studies drawing on the literature on fashion theory and incorporating many global case studies (as easy-to-read boxed material). Graphs, tables and diagrams will add texture to the written material. Approximately 200 colour images are planned to generously illustrate the historical and the contemporary tapestry of fashion. A dedicated interactive website will complement the text and ensure that students are in touch with the latest news, issues and trends.

Religion Explained? : A Philosophical Appraisal of the Cognitive Science of Religion

This study examines philosophically the main theories and methodological assumptions of the field known as the cognitive science of religion (CSR). The study makes a philosophically informed reconstruction of the methodological principles of the CSR, indicates problems with them, and examines possible solutions to these problems. The study focuses on several different CSR writers, namely, Scott Atran, Justin Barrett, Pascal Boyer and Dan Sperber. CSR theorising is done in the intersection between cognitive sciences, anthropology and evolutionary psychology. This multidisciplinary nature makes CSR a fertile ground for philosophical considerations coming from philosophy of psychology, philosophy of mind and philosophy of science. The study begins by spelling out the methodological assumptions and auxiliary theories of CSR writers by situating these theories and assumptions in the nexus of existing approaches to religion. The distinctive feature of CSR is its emphasis on information processing: CSR writers claim that contemporary cognitive sciences can inform anthropological theorising about the human mind and offer tools for producing causal explanations. Further, they claim to explain the prevalence and persistence of religion by cognitive systems that undergird religious thinking. I also examine the core theoretical contributions of the field focusing mainly on the (1) “minimally counter-intuitiveness hypothesis” and (2) the different ways in which supernatural agent representations activate our cognitive systems. Generally speaking, CSR writers argue for the naturalness of religion: religious ideas and practices are widespread and pervasive because human cognition operates in such a way that religious ideas are easy to acquire and transmit. The study raises two philosophical problems, namely, the “problem of scope” and the “problem of religious relevance”. The problem of scope is created by the insistence of several critics of the CSR that CSR explanations are mostly irrelevant for explaining religion. Most CSR writers themselves hold that cognitive explanations can answer most of our questions about religion. I argue that the problem of scope is created by differences in explanation-begging questions: the former group is interested in explaining different things than the latter group. I propose that we should not stick too rigidly to one set of methodological assumptions, but rather acknowledge that different assumptions might help us to answer different questions about religion. Instead of adhering to some robust metaphysics as some strongly naturalistic writers argue, we should adopt a pragmatic and explanatory pluralist approach which would allow different kinds of methodological presuppositions in the study of religion provided that they attempt to answer different kinds of why-questions, since religion appears to be a multi-faceted phenomenon that spans over a variety of fields of special sciences. The problem of religious relevance is created by the insistence of some writers that CSR theories show religious beliefs to be false or irrational, whereas others invoke CSR theories to defend certain religious ideas. The problem is interesting because it reveals the more general philosophical assumptions of those who make such interpretations. CSR theories can (and have been) interpreted in terms of three different philosophical frameworks: strict naturalism, broad naturalism and theism. I argue that CSR theories can be interpreted inside all three frameworks without doing violence to the theories and that these frameworks give different kinds of results regarding the religious relevance of CSR theories.

Vedestä vai Hengestä? : Uuras Saarnivaaran kasteteologia

Of water or the Spirit? Uuras Saarnivaara s theology of baptism The aim of the study was to investigate PhD and ThD Uuras Saarnivaara s views on baptism as well as their possible changes and the reasons for them. Dr Saarnivaara said himself that he searched for the truth about the relationship between baptism and faith for decades, and had faltered in his views. The method of this research is systematic analysis. A close study of the source material shows that Dr Saarnivaara s views on baptism have most likely changed several times. Therefore, special attention was paid to the time periods defined by when his literary works were published. This resulted in revealing the different perspectives he had on baptism. The fact that Dr Saarnivaara worked on two continents Europe and North America added a challenge to the research process. At the beginning of the research, I described Dr Saarnivaara s phases of life and mapped out his vast literary production as well as presented his theological basis. Saarnivaara s theological view on the means of grace and their interrelation in the church was influenced by the Laestadian movement, which caused him to adopt the view that the Holy Spirit does not dwell in the means of grace, but in the believers. Thus the real presence of Christ in the means of grace is denied. God s word is divided into Biblical revelation and proclamation by believers through the means of grace. Also, the sacraments are overshadowed by the preached word. Because grace is received through the word of the gospel preached publicly or privately by a believer, the preacher s status gains importance at the expense of the actual means of grace. Saarnivaara was intrigued by the content of baptism from the time he was a student until the end of his life. As a young theologian, he would adopt the opinions of his teachers as well as the view of the Evangelical Lutheran Church of Finland, which at the time was dominated by the pietistic movement and the teachings of J. T. Beck. After Saarnivaara had converted to the Laestadian movement, moved to the United States and started his Luther research, he adopted a view on baptism which was to a great extent in accordance with Luther and the Lutheran Symbolical Books. Saarnivaara considered his former views on baptism unbiblical and publicly apologised for them. In the 1950s, after starting his ministry within the Finnish neopietistic movements, Saarnivaara adopted a Laestadian-neopietistic doctrine of baptism. During his Beckian-pietistic era, Saarnivaara based his baptism theology on the event of the disciples of Jesus being baptised by John the Baptist, the revival of Samaria in the Book of Acts and the conversion of Cornelius and his family, all cases where the receiving of the Holy Spirit and the baptism were two separate events in time. In order to defend the theological unity of the Bible, Saarnivaara had to interpret Jesus teachings on baptism in the Gospels and the teachings of the Apostles in the New Testament letters from a viewpoint based on the three events mentioned above. During his Beckian-pietistic era, the abovementioned basic hermeneutic choice caused Saarnivaara to separate baptism by water and baptism by the Holy Spirit in his salvation theology. Simultaneously, the faith of a small child is denied, and rebirth is divided into two parts, the objective and the subjective, the latter being moved from the moment of baptism to a possible spiritual break-through at an age when the person possesses a more mature understanding. During his Laestadian-Lutheran era, Saarnivaara s theology of baptism was biblically consistent and the same for all people regardless of the person s age. Small children receive faith in baptism through the presence of Christ. The task of other people s faith is limited to the act of bringing the child to the baptism so that the child may receive his/her own faith from Christ and be born again as a child of God. The doctrine of baptism during Saarnivaara s Laestadian-neopietistic era represents in many aspects the emphases he presented during his first era, although they were now partly more radical. Baptism offers grace; it is not a means of grace. Justification, rebirth and salvation would take place later on when a person had reached an age with a more mature understanding through the word of God. A small child cannot be born again in baptism because being born again requires personal faith, which is received through hearing and understanding the law and the gospel. Saarnivaara s views on baptism during his first and third era are, unlike during his second era, quite controversial. The question of the salvation of a small child goes unanswered, or it is even denied. The central question during both eras is the demand of conversion and personal faith at a mature age. The background for this demand is in Saarnivaara s anthropology, which accentuates man s relationship to God as an intellectual and mental matter requiring understanding, and which needs no material instruments. The two first theological eras regarding Saarnivaara s doctrine of baptism lasted around ten years. The third era lasted over 40 years until his death.

Crystal structure from packing studies: application to the triclinic structure of the cyclic hexapeptide cyclo-(gly-tyr-gly)2

The paper describes a novel method of finding the position and orientation of a relatively rigid molecule in the unit cell from criteria concerning allowed contact distances between atoms. On application to the crystal structure of a hexapeptide, C25H31N6O8.2H2O, it was possible to solve the structure from this starting point, by a series of SFLS refinements with an increasingly larger number of reflexions at successive stages. The packing analysis succeeded, even though the water molecules were not included to start with.