Radiation induced depinning of a charge density wave system

The frequency-dependent response of a pinned charge density wave is considered in terms of forced vibration of an oscillator held in an anharmonic well. It is shown that the effective pinning-frequency can be reduced by applying a d.c. field. If a strong a.c. field, superposed on a d.c. field is applied on such a system “jumps” can be observed in the frequency dependent response of the system. The conditions at which these “jumps” occur are investigated with reference to NbSe3. The possibility of observing such phenomena in other systems like superionic conductors, non-linear dielectrics like ferroelectrics is pointed out. The characteristics are expressed in terms of some “scaled variables” — in terms of which the characteristics show a universal behaviour

Double walled carbon nanotubes as ultrafast optical switches

Pristine and molybdenum filled double walled carbon nanotubes (DWNTs) suspended in D2O show excellent ultrafast optical switching properties investigated through femtosecond Z-scan and degenerate pump-probe method using 50 fs pulses with central photon energy of 1.57 eV. For pristine-DWNT, the two photon absorption coefficient, beta and nonlinear refraction coefficient, n2 are 4.9×10−8 cm/W, and 9.5×10−11 cm2/W, respectively, which yield one photon figure of merit, W=133 and two photon figure of merit, T=0.4. The degenerate pump-probe measurements show strong photoinduced bleaching with biexponential decay with time constants ~150 and 600 fs. ©2009 American Institute of Physics

The business of myth-making: Mary Poppins, P.L. Travers and the Disney effect

In just one of the many extraordinary moments during the spectacular Opening Ceremony of the 2012 London Olympic Games, thirty Mary Poppinses floated into the stadium on their umbrellas to battle a 40 foot-long inflatable Lord Voldemort. This multi-million pound extravaganza was telecast to a global audience of over one billion people, highlighting in an extremely effective manner the grandeur and eccentricities of the host nation, and featuring uniquely British icons such as Mr Bean, James Bond, The Beatles and Harry Potter, as well as those quintessential icons of Englishness, the Royal Family, double-decker red buses and the National Health Service.

Combined effect of double antireflection coating and reversible molecular doping on performance of few-layer graphene/n-silicon Schottky barrier solar cells

Few-layer graphene films were grown by chemical vapor deposition and transferred onto n-type crystalline silicon wafers to fabricate graphene/n-silicon Schottky barrier solar cells. In order to increase the power conversion efficiency of such cells the graphene films were doped with nitric acid vapor and an antireflection treatment was implemented to reduce the sunlight reflection on the top of the device. The doping process increased the work function of the graphene film and had a beneficial effect on its conductivity. The deposition of a double antireflection coating led to an external quantum efficiency up to 90% across the visible and near infrared region, the highest ever reported for this type of devices. The combined effect of graphene doping and antireflection treatment allowed to reach a power conversion efficiency of 8.5% exceeding the pristine (undoped and uncoated) device performance by a factor of 4. The optical properties of the antireflection coating were found to be not affected by the exposure to nitric acid vapor and to remain stable over time.

Double standard polynucleotides: two typical alternative conformations for nucleic acids

Two typical alternative conformations for double strandee polynucleotides with Watson-Crick base pairing scheme are presented. these types avoid tangling of the chains. Representative models of these types with two different views, to show the similarity and dissimilarity between these models and the Watson-Crick model, are given.

Pyhä Teresa ja keskiajan mystiikan teoriat

In my dissertation I have studied St Teresa (1515-1582) in the light of medieval mystical theories. I have two main levels in my research: historical and theological. On the historical level I study St Teresa s personal history in the context of her family and the Spanish society. On the theological level I study both St Teresa s mysticism and her religious experience in the light of medieval mysticism. St Teresa wrote a book called Life , which is her narrative autobiography and story about her mystical spiritual formation. She reflected herself through biblical texts interpreting them in the course of the biblical hermeneutics like allegory, typology, tropology and anagogy. In addition to that she read others life stories from her period of time, but reflected herself only slightly through the sociological point of view. She used irony as a means to gain acceptance to her authority and motive to write. Her position has been described as a double bind because of writing at the request of educated men and to the non-educated women as she herself was uneducated. She used irony as a means to achieve valuation to women, to gain negative attributes connected to them and to gain authority to teach them mystical spirituality, the Bible and prayer. In this ironic tendency she was a feminist writer. In order to understand medieval mysticism I have written in the first chapter a review of the main trends in medieval mysticism in connection with the classical emotional theories. Two medieval mystical theories show an important role in St Teresa s mysticism. One is love mysticism and the other is the three partite way of mysticism (purification, illumination and union). The classic-philosophical emotional theories play a role in both patterns. The theory of love mysticism St Teresa interpreted in the traditional way stressing the spiritual meaning of love in connexion with God and neighbors. Love is an emotion, which is bound with other emotions, but all objects of love don t strengthen spiritual love. In the three partite way of mysticism purification means to find biblical values in life and to practice meditative self-knowledge theologically interpreted. In illumination human understanding has to be illuminated by God and united to mystical knowledge from God. St Teresa considered illumination a way to learn things. Illumination has also psychological aspects like recognition of many trials and pains, which come from life on earth. Theologically interpreted in illumination one should die to oneself, let oneself be transformed and renewed by God. I have also written a review of the modern philosophical discussion on personal identity where memory and mental experiences are important creators of personal identity. St Teresa bound medieval mystical teaching together with her personal religious experience. Her personal identity is by its character based on her narrative life story where mental experiences play important role. Previous researchers have labelled St Teresa as an ecstatic person whose experiences produced ecstatic phenomena to the mysticism. These phenomena combined with visions have in one respect made of her a person who has brought physical and visionary tendencies to theology. In spite of that she also represents a modern tendency trying to give words to experiences, which at first seem to be exceptional and extreme and which are easily interpreted as one-sided either physical or sexual or unsaid. In other respect I have stressed the personality of St Teresa that was represented as both strong and weak. The strong personality for her is demonstrated by religious faith and in its practice. The weak personality was for her a natural personal identity. St Teresa saw a unifying aspect in almost all. Firstly, her mysticism was aimed towards union with God and secondly, the unifying aspects and common rules in human relations in community life were central. Union with God is based on the fact that in a soul God is living in its centre, where God is present in the Trinitarian way. The picture of God in ourselves is a mirror but to get to know God better is to recognize his/her presence in us. When the soul recognizes itself as a dwelling place of God, it knows itself as God knows him/herself. There is equality between God and the soul. To be a Christian means to participate in God in his Trinitarian being. The participation to God is a process of divinization that puts a person into transformation, change and renewal. The unitive aspect concludes also knowledge of opposites between experience of community and solitude as well as community and separateness. As a founder of monasteries St Teresa practiced theology of poverty. She renewed the monastic life founding a rule called discalced that stressed ascetic tendencies. Supporters of her work were after the difficulties in the beginning both society and churchly leaders. She wrote about the monasteries including in her description at times seriousness at times humor and irony. Her stories are said to be picaresque histories that contain stories of ordinary laymen and many unexpected occasions. She exercised a kind of Bakhtinian dialogue in her letters. St Teresa stressed the virtues like sacrifice, determination and courage in the monastic life. Most of what she taught of virtues is based on biblical spirituality but there are also psychological tendencies in her writings. The theological pedagogical advice is mixed with psychology, but she herself made no distinction between different aspects in her teaching. To understand St Teresa and her mysticism is to recognize that she mixes her personal religious experience and mysticism, which widens mysticism to religious experience in a new way, although this corresponds also the very definition of mysticism. St Teresa concentrated on mental-spiritual experiences and the aim of her mystical teaching was to produce a human mind well cured like a garden that has God as its gardener.

Patriarkkana ikuisuuden performanssissa : Maskuliinisuuden ja miehen ruumiillisuuden rakentuminen mormonien Duties and Blessings of the Priesthood -opetuskäsikirjassa

The material I analyze for my master's thesis is a teaching manual used by the Mormons (the Church of Jesus Christ of Latter-day Saints), called "Duties and Blessings of the Priesthood". This work includes numerous lesson plans, each one with a separate topic. The manual is intended especially for teaches, but can also be used for individual study. The main target of my research is to find out how men and their bodies are constructed in the manual. Prescriptive texts together with narrative stories and illustrations create a multifaceted picture of Mormon notions of masculinity and corporeality. I approach my research material from a constructivist perspective. I build my interpretative reading upon Critical Discourse Analysis. I am especially interested in how the manual interprets and understands connections between gender, embodiment and religion. I understand gender in Judith Butler's terms, as a performance of styled and repeated gestures. Some of the discussions I raise in my work draw upon the disciplines of Critical Men's Studies and Sociology of Religion. In Mormonism, gender is thought to be an elementary part of human ontology. It is an eternal trait inherited from God the Father (and God the Mother). The place of men in Mormon cosmology is determined by their double role as patriarchs, fathers and priests. The main objective of mortal life is to gain salvation together with one's family. The personal goal of a Mormon man is to one day become a god. Patriarchs are responsible for the spiritual and material well-being of their family. The head of a household should be gentle and loving, but still an unconditional authority. In the manual, a Mormon man is depicted as a successor of mythical and exemplary men of sacred history. The perfect and sinless body of Jesus Christ serves as an ideal for the male body. Mormon masculinity is also defined by priesthood - the holy power of God - which is given to practically all male Mormons. Through the priesthood, a Mormon man serves as the governor of God on Earth. The Mormon priest has the authority to bind the immanent and the transcendent worlds together with gestures, poses and motions performed with his body. In Mormonism, the body also symbolizes a temple or a space where the sacred meets the profane. Because the priesthood borne by a man is holy, he has to treat his body accordingly. The body is valuable in itself, without it one cannot be saved. Men are forbidden of polluting their bodies by using stimulants or by having sexual relations out of wedlock. A priesthood holder must uphold healthy habits, dress neatly, and conduct himself in a temperate manner. He must also be outgoing and attentive. The manual suggests that a man's goodness or wickedness can be perceived from his external appearance. The Church of Jesus Christ of Latter-day Saints is a hierarchical and man-led organisation. The ideals of gender and corporeality are set by a homogenous priesthood leadership that consists mainly of white heterosexual American men. The larger Mormon community can control individual men by sanctioning. Growing as a Mormon man happens under the guidance of one's reference group.

Unbounding the interaction design problem: The contribution of HCI in three interventions for well-being

In this paper we consider HCI's role in technology interventions for health and well-being. Three projects carried out by the authors are analysed by appropriating the idea of a value chain to chart a causal history from proximal effects generated in early episodes of design through to distal health and well-being outcomes. Responding to recent arguments that favour bounding HCI's contribution to local patterns of use, we propose an unbounded view of HCI that addresses an extended value chain of influence. We discuss a view of HCI methods as mobilising this value chain perspective in multi-disciplinary collaborations through its emphasis on early prototyping and naturalistic studies of use.

Conformation of polypeptide-chains containing both l-residues and D-residues .2. Double-helical structures of poly-ld-peptides

Polypeptides with alternating L- and D-amino acid residues can take up stereochemically satisfactory coaxial double-helical structures, both antiparallel and parallel, which are stabilized by systematic interchain NH O hydrogen bonds. Semiempirical energy calculations over allowed regions of conformational space have yielded the characteristics of these double-helices. There are four possible types of antiparallel double-helices - A3, A4, A5 and A6, with n, the number of LD peptide units per turn, around 2.8, 3.6, 4.5 and 5.5 respectively, while for the parallel double-helices there are two types, P3 and P4, having similar helical parameters as in A3 and A4. The hydrogen-bonding scheme restricts the pitch in all the models to the narrow range of 10.0 to 11.5 Å. All these helices have large central cores whose radii increase proportionately with n. In this respect, A3 and A4 are suitable models for the structure of gramicidin A. In terms of their relative energies, antiparallel double-helices are marginally more stable than those with parallel strands. Our results indicate that the energy differences amongst the members in the antiparallel family are not significant and thus provide an explanation for the polymorphism reported for poly(γ-benzyl-LD-glutamate).

Dissipative dynamics of a harmonic oscillator: A nonperturbative approach

Starting from a microscopic theory, we derive a master equation for a harmonic oscillator coupled to a bath of noninteracting oscillators. We follow a nonperturbative approach, proposed earlier by us for the free Brownian particle. The diffusion constants are calculated analytically and the positivity of the master equation is shown to hold above a critical temperature. We compare the long time behavior of the average kinetic and potential energies with known thermodynamic results. In the limit of vanishing oscillator frequency of the system, we recover the results of the free Brownian particle.

Taiwanese migrants in Australia: An investigation of their accultration and well-being

Taiwanese migrants settled in Brisbane, Australia (N=271) completed a questionnaire battery available in both Mandarin and English. A series of multiple and hierarchical regression analyses were used to investigate the factors associated with these migrants’ acculturation and indicators of psychological well-being. Results indicated that various personal factors (age, English language proficiency and duration of stay) were associated with acculturation and indicators of psychological wellbeing. Acculturation was not associated with wellbeing. Social support was associated with the indicators of the participants’ wellbeing. The outcome indicated that although associated with similar personal and environmental factors, acculturation and psychological wellbeing occurred separately. The study highlights the significance of certain personal resources and social support.

Thermodynamics of Monosaccharide and Disaccharide Binding to Erythrina corallodendron Lectin

Isothermal titration calorimetry measurements of the binding of 2′-fucosyllactose, lactose, N-acetyllactosamine, galactopyranose, 2-acetamido-2-deoxygalactopyranoside, methyl α-N-dansylgalactosaminide (Me-α-DNS-GalN), methyl α-D-galactopyranoside, methyl β-D-galactopyranoside, and fucose to Erythrina corallodendron lectin (ECorL), a dimer with one binding site per subunit, were performed at 283-286 and 297-299 K. The site binding enthalpies, ΔHb, with the exception of Me-α-DNS-GalN, are the same at both temperatures and range from −47.1 ± 1.0 kJ mol−1 for N-acetyllactosamine to −4.4 ± 0.3 kJ mol−1 for fucose, and the site binding constants range from 3.82 ± 0.9 × 105 M−1 for Me-α-DNS-GalN at 283.2 K to 0.46 ± 0.05 × 103 M−1 for fucose at 297.2 K. The binding reactions are mainly enthalpically driven except for fucose and exhibit enthalpy-entropy compensation. The binding enthalpies of the disaccharides are about twice the binding enthalpies of the monosaccharides in contrast to concanavalin A where the binding enthalpies do not double for the disaccharides. Differential scanning calorimetry measurements show that denaturation of the ECorL dimer results in dissociation into its monomer subunits. The binding constants from the increase in denaturation temperature of ECorL in the presence of saccharides are in agreement with values from isothermal titration calorimetry results. The thermal denaturation of ECorL occurs around 333 K, well below the 344-360 K denaturation temperature of other legume lectins of similar size and tertiary structure, undoubtedly due to the difference in its quaternary structure relative to other legume lectins. This is also apparent from the independent unfolding of its two domains.

Analysis of the amino acid sequences of plant Bowman-Birk inhibitors

Plant seeds contain a large number of protease inhibitors of animal, fungal, and bacterial origin. One of the well-studied families of these inhibitors is the Bowman-Birk family(BBI). The BBIs from dicotyledonous seeds are 8K, double-headed proteins. In contrast, the 8K inhibitors from monocotyledonous seeds are single headed. Monocots also have a 16K, double-headed inhibitor. We have determined the primary structure of a Bowman-Birk inhibitor from a dicot, horsegram, by sequential edman analysis of the intact protein and peptides derived from enzymatic and chemical cleavage. The 76-residue-long inhibitor is very similar to that ofMacrotyloma axillare. An analysis of this inhibitor along with 26 other Bowman-Birk inhibitor domains (MW 8K) available in the SWISSPROT databank revealed that the proteins from monocots and dicots belong to related but distinct families. Inhibitors from monocots show larger variation in sequence. Sequence comparison shows that a crucial disulphide which connects the amino and carboxy termini of the active site loop is lost in monocots. The loss of a reactive site in monocots seems to be correlated to this. However, it appears that this disulphide is not absolutely essential for retention of inhibitory function. Our analysis suggests that gene duplication leading to a 16K inhibitor in monocots has occurred, probably after the divergence of monocots and dicots, and also after the loss of second reactive site in monocots.

Multifunctional RNA silencing pathway polymerase QDE-1 of Neurospora crassa

Double-stranded RNA and associated proteins are known to regulate the gene expression of most eukaryotic organisms. These regulation pathways have different components, outcomes and distinct nomenclature depending on the model system, and often they are referred to collectively as RNA silencing. In many cases, RNA-dependent RNA polymerases (RdRPs) are found to be involved in the RNA silencing, but their targets, activities, interaction partners and reaction products remain enigmatic. In the filamentous fungus Neurospora crassa, the RdRP QDE-1 is critical for silencing of transgenes a phenomenon known as quelling. In this thesis the structure, biochemical activities and biological functions of QDE-1 were extensively studied. This dimeric RdRP was shown to possess five distinct catalytic in vitro activities that could be dissected by mutagenesis and by altering reaction conditions. The biochemical characterization implied that QDE-1 is actually an active DNA-dependent RNA polymerase that has additional RdRP activity. It also provided a structural explanation for the dimerization and suggested a biological framework for the functions of QDE-1 in vivo. (I) QDE-1 was also studied in a broader context along with the other components of the quelling pathway. It was shown that DNA damage in Neurospora causes a dramatic increase in the expression level of the Argonaute protein QDE-2 as well as the synthesis of a novel class of small RNAs known as qiRNAs. The accumulation of qiRNAs was shown to be dependent on several quelling components, and particularly to be derived from an aberrant ssRNA (aRNA) molecule that is synthesized by QDE-1 in the nucleus. The genomic distribution of qiRNA targets was analyzed and the possible biological significance of qiRNAs was studied. Importantly, qiRNAs are the first class of small RNAs that are induced by DNA damage. (II) After establishing that QDE-1 is a multifunctional RNA polymerase with several activities, template specificities and subcellular locations, the focus was turned onto its interaction partners. It had been previously known that QDE-1 associates with Replication Protein A (RPA), but the RecQ helicase QDE-3 was now shown to regulate this interaction. RPA was also observed to promote QDE-1 dependent dsRNA synthesis in vitro. By characterizing the interplay between QDE-1, QDE-3 and RPA, a working model of quelling and qiRNA pathways in Neurospora was presented. (III) This work sheds light on the complexity of the various RNA silencing pathways of a fungal model system. It shows how an RdRP can regulate gene expression on many levels, and suggests novel lines of research in other eukaryotic organisms.

Sostdc1 Plays an Essential Role in Mammalian Tooth Patterning : Insight into the Rodent Dental Evolution

This thesis work focuses on the role of TGF-beta family antagonists during the development of mouse dentition. Tooth develops through an interaction between the dental epithelium and underlying neural crest derived mesenchyme. The reciprocal signaling between these tissues is mediated by soluble signaling molecules and the balance between activatory and inhibitory signals appears to be essential for the pattern formation. We showed the importance of Sostdc1 in the regulation of tooth shape and number. The absence of Sostdc1 altered the molar cusp patterning and led to supernumerary tooth formation both in the molar and incisor region. We showed that initially, Sostdc1 expression is in the mesenchyme, suggesting that dental mesenchyme may limit supernumerary tooth induction. We tested this in wild-type incisors by minimizing the amount of mesenchymal tissue surrounding the incisor tooth germs prior to culture in vitro. The cultured teeth phenocopied the extra incisor phenotype of the Sostdc1-deficient mice. Furthermore, we showed that minimizing the amount of dental mesenchyme in cultured Sostdc1-deficient incisors caused the formation of additional de novo incisors that resembled the successional incisor development resulting from activated Wnt signaling. Sostdc1 seemed to be able to inhibit both mesenchymal BMP4 and epithelial canonical Wnt signaling, which thus allows Sostdc1 to restrict the enamel knot size and regulate the tooth shape and number. Our work emphasizes the dual role for the tooth mesenchyme as a suppressor as well as an activator during tooth development. We found that the placode, forming the thick mouse incisor, is prone to disintegration during initiation of tooth development. The balance between two mesenchymal TGF-beta family signals, BMP4 and Activin is essential in this regulation. The inhibition of BMP4 or increase in Activin signaling led to the splitting of the large incisor placode into two smaller placodes resulting in thin incisors. These two signals appeared to have different effects on tooth epithelium and the analysis of the double null mutant mice lacking Sostdc1 and Follistatin indicated that these TGF-beta inhibitors regulate the mutual balance of BMP and Activin in vivo. In addition, this work provides an alternative explanation for the issue of incisor identity published in Science by Tucker et al. in 1998 and proposes that the molar like morphology that can be obtained by inhibiting BMP signaling is due to partial splitting of the incisor placodes and not due to change in tooth identity from the incisor to the molar. This thesis work presents possible molecular mechanisms that may have modified the mouse dental pattern during evolution leading to the typical rodent dentition of modern mouse. The rodent dentition is specialized for gnawing and consists of two large continuously growing incisors and toothless diastema region separating the molars and incisors. The ancestors of rodents had higher number of more slender incisors together with canines and premolars. Additionally, murine rodents, which include the mouse, have lost their ability for tooth replacement. This work has revealed that the inhibitory molecules appear to play a role in the tooth number suppression by delineating the spatial and temporal action of the inductive signals. The results suggest that Sostdc1 plays an essential role in several stages of tooth development through the regulation of both the BMP and Wnt pathway. The work shows a dormant sequential tooth forming potential present in wild type mouse incisor region and gives a new perspective on tooth suppression by dental mesenchyme. It reveals as well a novel mechanism to create a large mouse incisor through the regulation of mesenchymal balance between inductive and inhibitory signals.