Distribution by Scientific Domains

Terms modified by Disordered

  • disordered breathing
  • disordered child
  • disordered eating
  • disordered material
  • disordered molecule
  • disordered offender
  • disordered patient
  • disordered phase
  • disordered protein
  • disordered regions
  • disordered semiconductor
  • disordered states
  • disordered structure
  • disordered system
  • disordered water molecule

  • Selected Abstracts

    Nd2Ba2CaZn2Ti3O14.4: A New High Dielectric Constant Oxide Having a Disordered (Cubic) Perovskite Structure.

    CHEMINFORM, Issue 36 2003
    Pika Jha
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    Mental health patients in criminal justice populations: needs, treatment and criminal behaviour

    J. Keene PhD Professor of Primary Care
    Background Government policy requires that health and social care agencies work more closely together and in partnership with the criminal justice system. There is a well-established relationship between crime and mental disorder. Method The Tracking Project provides for the first time in England the means of collating and analysing data on mental disorder (defined as receiving secondary care as patients of a Mental Health Trust) and crime (defined as all those charged with an offence). Data were collected over a three-year period for all individuals who had contact with the criminal justice system and mental health services in an English county. Results In a county population of 800,400, some 30,329 were offenders. More than a third had used a health or social care service during the three-year period; 8.0% were mentally disordered. Those offenders aged 25,64 and who contacted the police more than once were significantly more likely to be mentally disordered. Type of offence was also a relevant variable. The probation service showed broadly similar results. Discussion The research has provided for the first time substantive quantitative evidence of the relationship between crime and mental disorder. The results can be used as the basis for further work to target assessment and risk reduction measures at those most at risk. Copyright 2003 Whurr Publishers Ltd. [source]


    Research Summary: Civil gang injunctions are an increasingly popular gang suppression tactic. This article reports on the first scientific evaluation of the community impact of this strategy. San Bernardino residents in five neighborhoods were surveyed about their perceptions and experience of crime, gang activity, and neighborhood quality 18 months before and 6 months after the issuance of an injunction. Analyses indicated positive evidence of short-term effects in the disordered, primary injunction area, including less gang presence, fewer reports of gang intimidation, and less fear of confrontation with gang members, but no significant changes in intermediate or long-term outcomes except lower fear of crime. Comparison of this injunction area with a previous one suggested that improvements in neighborhood dynamics might accrue over the long term. Negative effects were observed in the secondary, less disordered injunction area. Policy Implications: This study suggests that the strategic suppression of gang member activities may translate into modest immediate improvements in community safety and well-being. Furthermore, the findings suggest that law enforcement use caution regarding the size of an injunction area and the type of gang targeted by the tactic. Coupling an injunction with efforts to improve neighborhood social organization and provide positive alternatives for gang members might substantially improve its effectiveness. [source]

    The Politics of Disciplining Water Rights

    Rutgerd Boelens
    ABSTRACT This article examines how the legal systems of Andean countries have dealt with the region's huge plurality of local water rights, and how official policies to ,recognize' local rights and identities harbour increasingly subtle politics of codification, confinement and disciplining. The autonomy and diversity of local water rights are a major hindrance for water companies, elites and formal rule-enforcers, since State and market institutions require a predictable, uniform playing field. Complex local rights orders are seen as irrational, ill-defined and disordered. Officialdom cannot simply ignore or oppress the ,unruliness and disobedience' of local rights systems: rather it ,incorporates' local normative orders that have the capacity to adequately respond to context-based needs. This article examines a number of evolving, overlapping legal domination strategies, such as the ,marrying' of local and official legal systems in ways that do not challenge the legal and power hierarchy; and reviews the ways in which official regulation and legal strategies deny or take into consideration local water rights repertoires, and the politics of recognition that these entail. Post-colonial recognition policies are not simply responses to demands by subjugated groups for greater autonomy. Rather, they facilitate the water bureaucracy's political control and help neoliberal sectors to incorporate local water users' rights and organizations into the market system , even though many communities refuse to accept these policies of recognition and politics of containment. [source]

    Motor stereotypies in children with autism and other developmental disorders

    The purpose of the study was to count and characterize the range of stereotypies , repetitive rhythmical, apparently purposeless movements , in developmentally impaired children with and without autism, and to determine whether some types are more prevalent and diagnostically useful in children with autism. We described each motor stereotypy recorded during 15 minutes of archived videos of standardized play sessions in 277 children (209 males, 68 females; mean age 4y 6mo [SD 1y 5mo], range 2y 11mo,8y 1mo), 129 with autistic disorder (DSM-III-R), and 148 cognitively-matched non-autistic developmentally disordered (NADD) comparison children divided into developmental language disorder and non-autism, low IQ (NALIQ) sub-groups. The parts of the body involved and characteristics of all stereotypies were scored blind to diagnosis. More children with autism had stereotypies than the NADD comparison children. Autism and, to a lesser degree, nonverbal IQ (NVIQ) <80, especially in females contributed independently to the occurrence, number, and variety of stereotypies, with non-autistic children without cognitive impairment having the least number of stereotypies and children with autism and low NVIQ the most. Autism contributed independently to gait and hand/finger stereotypies and NVIQ <80 to head/trunk stereotypies. Atypical gazing at fingers and objects was rare but virtually limited to autism. Stereotypies are environmentally modulated movement disorders, some highly suggestive, but not pathognomonic, of autism. Their underlying brain basis and genetic correlates need investigation. [source]

    Forensic psychiatry, ethics and protective sentencing: what are the limits of psychiatric participation in the criminal justice process?

    S. N. Verdun-Jones
    As clinicians, psychiatrists are unequivocally dedicated to relieving the suffering of those who are afflicted with mental disorders. However, the public and those individuals, who are assessed, find it difficult to draw a distinction between forensic psychiatrists acting in a clinical role and the very same professionals acting in an evaluative role, on behalf of the state. This paper examines the ethical issues raised by psychiatric involvement in the sentencing process. It rejects the view that a forensic psychiatrist, who undertakes an evaluation for the state, is to be considered as an advocate of justice who is not bound by conventional ethical duties to the individual whom he or she assesses. It contends that the forensic psychiatrist has an important role to play in presenting evidence that may result in the mitigation of the sentence that may be imposed on a person who is mentally disordered. The paper will focus on these issues in the particular context of the situation in England and Wales, Canada and the United States. [source]

    A Crystalline Phase Transition and Optical Properties in a CoIICuII Oxamato-Bridged Ferrimagnetic Chain

    Cynthia L. M. Pereira
    Abstract The compound [CoCu(opba)(DMSO)3] (1) [opba = ortho -phenylenebis(oxamato)] has been synthesized and characterized. Its crystal structure has been analyzed by X-ray diffraction techniques at 100 and 298 K. A structural phase-transition has been detected at around 150 K. An orthorhombic crystalline system is found at both temperatures, with very similar unit-cell dimensions. At room temperature 1 crystallizes in the Pnam space group (, -1 phase), with a = 7.6712(2), b = 14.8003(3), c = 21.0028(5) , and Z = 4, whereas at low temperature it crystallizes in the Pna21 space group (, -1 phase), with a = 7.3530(2), b = 14.5928(4), c = 21.0510(7) , and Z = 4. Both crystalline phases consist of linearly ordered bimetallic chains with the [Cu(opba)]2, units tied by CoII ions to form a one-dimensional system. The DMSO molecules in , -1, which are coordinated to either CuII or CoII, are disordered. At low temperature, a small reorganization of the CuII and CoII environments is observed. The origin of this phase transition, which is completely reversible, is the modification of the crystalline packing with the temperature. Linear birefringence measurements were done on single crystals in the 100,300 K temperature range. Around 150 K, the linear birefringence curve shows an inflexion that is interpreted as being related to the conversion of ,-1 into , -1. Both dc and ac magnetic measurements were performed on the polycrystalline sample. The results reveal a one-dimensional ferrimagnetic behavior. Single crystal optical characterization at room temperature shows that 1 presents a very strong dichroism superposed on the linear birefringence. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

    Nonquenchable Chemical Order,Disorder Phase Transition in Yttrium Oxyfluoride

    Igor Levin
    Abstract A chemical order,disorder polymorphic phase transition in yttrium oxyfluoride (YOF) was studied in situ by X-ray and neutron powder diffraction. The high-temperature form of YOF crystallizes with a cubic Fmm fluorite structure in which the O and F atoms are disordered among the tetrahedrally coordinated sites. The low-temperature form of YOF exhibits rhombohedral Rm symmetry and evolves from the high-temperature form by the phase transition associated with the ordering of the O and F atoms. The transition occurs around 560 C. The superstructure contains layers of [OY4] and [FY4] tetrahedra alternating along the c -axis of the trigonal cell (parallel to the <111> direction of the parent cubic structure). The ordering of the O and F atoms is accompanied by the significant displacements of the Y, O, and F atoms from their ideal positions in the cubic phase. Bond valence sum calculations indicate considerable bond strain for both O and F in the cubic structure; the strain is relieved in the ordered low-temperature phase. The order,disorder transition in YOF is completely reversible and exhibits fast nonquenchable kinetics. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

    New Molecular Charge-Transfer Salts of TM-TTF and BMDT-TTF with Thiocyanate and Selenocyanate Complex Anions [TMTTF = Tetramethyltetrathiafulvalene; BMDT-TTF = Bis(methylenedithio)tetrathiafulvalene]

    Marta Mas-Torrent
    Abstract Three new charge-transfer salts of tetrathiafulvalene (TTF)-based donors with thiocyanato- or selenocyanato-metal complex anions have been synthesised. The salts isolated were [BMDT-TTF]4[Cr(NCS)6] (1), [TM-TTF]4[Cr(NCS)6]2CH3CN (2) and [TM-TTF]4[Cr(NCSe)6]2CH3CN (3) [BMDT-TTF = bis(methylenedithio)tetrathiafulvalene and TM-TTF = tetramethyltetrathiafulvalene]. Single crystals of compound 1 crystallise in the monoclinic C2/c space group with a = 37.286(3), b = 10.0539(6), c = 21.069(2) , , = 124.348(4), V = 6520.9(9) 3 and Z = 4. Compound 3 was also suitable for an X-ray diffraction study, however the anionic part, [Cr(NCSe)6], was highly disordered and the best solution gave a final R factor of 16.4%. A solution was found for the monoclinic space group C2/m with a = 13.787(3), b = 19.507(3), c = 14.735(5) , , = 102.90(3), V = 3862.9(17) 3 and Z = 2. For compound 1 there are several SS close atomic contacts between the donors and acceptors, but there is no discernible magnetic exchange between ions. Such an interaction was previously observed in related salts such as [TTF][Cr(NCS)4(phenanthroline)2] and [donor][M(NCS)4(isoquinoline)2] [M = Cr, Fe and donor = TTF, BEDT-TTF or TM-TTF (tetramethyltetrathiafulvalene)]. Compounds 1 to 3 are all paramagnetic semiconductors in which the magnetic susceptibility is dominated by the Cr-containing anions. The structure-function relationship, along with a comparison with related compounds, indicates that there is no long-range magnetic order because there are no ,-stacking interactions between donor and acceptor; these types of interactions are seen in all of the bulk magnets of this type in which the donor spin is magnetically coupled to the anion. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    Mechanism of Selective and Unselective Enclathration by a Host Compound Possessing Open, Flexible Host Frameworks

    Kazunori Nakano
    Abstract Molecular recognition of o -, m -, and p -xylenes (oX, mX, and pX) through enclathration of cholic acid (CA) is described. All of the xylenes give lattice inclusion crystals with CA, and crystallographic studies reveal that they are included in different open host frameworks. In particular, oX has two polymorphs, depending on the recrystallization temperatures. Competitive recrystallization from mixtures of xylenes resulted in selective enclathrations and the formation of racemic mixed crystals. In the presence of an equimolar amount of oX, CA selectively includes mX or pX in the host frameworks, which are identical to those obtained from the pure mX or pX, respectively. The low affinity of oX is explained in terms of a lower stability of CAoX than of the other two complexes, as judged from the low PCcavity, the volume ratio of the guest compound to the host cavity. Meanwhile, mixtures of mX and pX yield inclusion crystals that accommodate both of the guests. These have the same open host framework as obtained from pure mX, and the guest components are disordered statically in the host cavity. The ratios of the xylene mixtures in the single crystals are similar to those in the original recrystallization mixtures, and also in the bulk crystals, indicating that CA forms mixed crystals of mX and pX. This non-selectivity is attributed to the similar stabilities of CAmX and CApX, according to the moderate PCcavity. The inclusion behavior of CA from mixtures of xylenes is quite similar to chiral recognition by diastereomer-salt methods. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    Structural disorder in amyloid fibrils: its implication in dynamic interactions of proteins

    FEBS JOURNAL, Issue 19 2009
    P. Tompa
    Proteins are occasionally converted from their normal soluble state to highly ordered fibrillar aggregates (amyloids), which give rise to pathological conditions that range from neurodegenerative disorders to systemic amyloidoses. Recent methodological advances in solid-state NMR and EPR spectroscopy have enabled determination of the 3D structure of several amyloids at residue-level resolution. The general picture that emerges is that amyloids constitute parallel , sheets, in which individual polypeptide chains run roughly perpendicular to the major axis of the fibril and are stacked in-register. Thus, the unifying theme of amyloid formation is the structural transition from an initial globular or intrinsically disordered state to a highly ordered regular form. In this minireview, we show that this description is somewhat oversimplified, because part of the polypeptide chain in the amyloid remains intrinsically disordered and does not become part of the ordered core. As demonstrated through examples such as the amyloids of ,-synuclein and A, peptide and the yeast prions HET-s and Ure2p, these disordered segments are depleted in amino acids NQFYV and are enriched in DEKP. They are also significantly more charged and have a higher predicted disordered value than segments in the cross-, core. We suggest that structural disorder in amyloid is a special case of ,fuzziness', i.e. disorder in the bound state that may serve different functions, such as the accommodation of destabilizing residues and the mediation of secondary interactions between protofibrils. [source]

    The Influence of Film Morphology in High-Mobility Small-Molecule:Polymer Blend Organic Transistors

    Jeremy Smith
    Abstract Organic field-effect transistors (OFETs) based upon blends of small molecular semiconductors and polymers show promise for high performance organic electronics applications. Here the charge transport characteristics of high mobility p-channel organic transistors based on 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene:poly(triarylamine) blend films are investigated. By simple alteration of the film processing conditions two distinct film microstructures can be obtained: one characterized by small spherulitic grains (SG) and one by large grains (LG). Charge transport measurements reveal thermally activated hole transport in both SG and LG film microstructures with two distinct temperature regimes. For temperatures >115,K, gate voltage dependent activation energies (EA) in the range of 25,60 meV are derived. At temperatures <115,K, the activation energies are smaller and typically in the range 5,30 meV. For both film microstructures hole transport appears to be dominated by trapping at the grain boundaries. Estimates of the trap densities suggests that LG films with fewer grain boundaries are characterized by a reduced number of traps that are less energetically disordered but deeper in energy than for small SG films. The effects of source and drain electrode treatment with self-assembled monolayers (SAMs) on current injection is also investigated. Fluorinated thiol SAMs were found to alter the work function of gold electrodes by up to ,1,eV leading to a lower contact resistance. However, charge transport analysis suggests that electrode work function is not the only parameter to consider for efficient charge injection. [source]

    The Impact of Polymer Regioregularity on Charge Transport and Efficiency of P3HT:PCBM Photovoltaic Devices

    Ralf Mauer
    Abstract The charge transport in pristine poly(3-hexylthiophene) (P3HT) films and in photovoltaic blends of P3HT with [6,6]-phenyl C61 butyric acid methyl ester (PCBM) is investigated to study the influence of charge-carrier transport on photovoltaic efficiency. The field- and temperature dependence of the charge-carrier mobility in P3HT of three different regioregularities, namely, regiorandom, regioregular with medium regioregularity, and regioregular with very high regioregularity are investigated by the time-of-flight technique. While medium and very high regioregularity polymers show the typical absorption features of ordered lamellar structures of P3HT in the solid state even without previous annealing, films of regiorandom P3HT are very disordered as indicated by their broad and featureless absorption. This structural difference in the solid state coincides with partially non-dispersive transport and hole mobilities h of around 10,4 and 10,5,cm2 V,1 s,1 for the high and medium regioregularity P3HT, respectively, and a slow and dispersive charge transport for the regiorandom P3HT. Upon blending the regioregular polymers with PCBM, the hole mobilities are typically reduced by one order of magnitude, but they do not significantly change upon additional post-spincasting annealing. Only in the case of P3HT with high regioregularity are the electron mobilities similar to the hole mobilities and the charge transport is, thus, balanced. Nonetheless, devices prepared from both materials exhibit similar power conversion efficiencies of 2.5%, indicating that very high regioregularity may not substantially improve order and charge-carrier transport in P3HT:PCBM and does not lead to significant improvements in the power-conversion efficiency of photovoltaic devices. [source]

    Statistical behavior of complex cancer karyotypes

    Mattias Hglund
    Epithelial tumors commonly show complex and variable karyotypes that obscure the identification of general patterns of the karyotypic evolution. To overcome some of these problems, we previously systematically analyzed the accumulated cytogenetic data from individual tumor types by using various statistical means. In the present study, we compare previous results obtained for nine tumor types and perform several meta-analyses of data obtained from a number of epithelial tumors, including head and neck, kidney, bladder, breast, colorectal, ovarian, and lung cancer, as well as from malignant melanoma and Wilms tumor, with the specific aim of discovering common patterns of karyotypic evolution. We show that these tumors frequently develop through a hypo- or a hyperdiploid pathway and progress by an increasing number of alternative imbalances through at least two karyotypic phases, Phases I and II, and possibly through a third, Phase III. During Phase I, the karyotypes exhibited a power law distribution of both the number of changes per tumor and the frequency distribution at which bands were involved in breaks. At the transition from Phase I to Phase II/III, the observed power law distributions were lost, indicating a transition from an ordered and highly structured process to a disordered and chaotic pattern. The change in karyotypic orderliness at the transition from Phase I to Phase II/III was also shown by a drastic difference in karyotypic entropy. 2005 Wiley-Liss, Inc. [source]

    Nodal protrusions, increased Schmidt-Lanterman incisures, and paranodal disorganization are characteristic features of sulfatide-deficient peripheral nerves

    GLIA, Issue 6 2007
    Tomiko Hoshi
    Abstract Galactocerebroside and sulfatide are two major glycolipids in myelin; however, their independent functions are not fully understood. The absence of these glycolipids causes disruption of paranodal junctions, which separate voltage-gated Na+ and Shaker -type K+ channels in the node and juxtaparanode, respectively. In contrast to glial cells in the central nervous system (CNS), myelinating Schwann cells in the peripheral nervous system (PNS) possess characteristic structures, including microvilli and Schmidt-Lanterman incisures, in addition to paranodal loops. All of these regions are involved in axo,glial interactions. In the present study, we examined cerebroside sulfotransferase-deficient mice to determine whether sulfatide is essential for axo,glial interactions in these PNS regions. Interestingly, marked axonal protrusions were observed in some of the nodal segments, which often contained abnormally enlarged vesicles, like degenerated mitochondria. Moreover, many transversely cut ends of microvilli surrounded the mutant nodes, suggesting that alignments of the microvilli were disordered. The mutant PNS showed mild elongation of nodal Na+ channel clusters. Even though Caspr and NF155 were completely absent in half of the paranodes, short clusters of these molecules remained in the rest of the paranodal regions. Ultrastructural analysis indicated the presence of transverse bands in some paranodal regions and detachment of the outermost several loops. Furthermore, the numbers of incisures were remarkably increased in the mutant internode. Therefore, these results indicate that sulfatide may play an important role in the PNS, especially in the regions where myelin,axon interactions occur. 2007 Wiley-Liss, Inc. [source]

    The Influence of Alkyl-Chain Length on Beta-Phase Formation in Polyfluorenes

    Daniel W. Bright
    Abstract Di- n -alkyl substituted polyfluorenes with alkyl chain lengths of 6, 7, 8, 9, and 10 carbon atoms (PF6, PF7, PF8, PF9, and PF10) are studied in dilute solution in MCH using optical spectroscopy. Beta-phase is formed upon cooling in solutions (, 7,g mL,1) of PF7, PF8, and PF9 only, which is observed as an equilibrium absorption peak at , 437,nm and strong changes in the emission spectra. Beta-phase is formed upon thermal cycling to low temperature in solutions (,7,g mL,1) of PF7, PF8, and PF9, which is observed as an equilibrium absorption peak at , 437,nm and strong changes in the emission spectra. Beta phase is found to occur more favorably in PF8 than in PF7 or PF9, which is attributed to a balance between two factors. The first is the dimer/aggregate formation efficiency, which is poorer for longer (more disordered) alkyl chain lengths, and the second is the Van der Waals bond energy available to overcome the steric repulsion and planarize the conjugated backbone, which is insufficient in the PF6 with a shorter alkyl chain. Beta phase formation is shown to be a result of aggregation, not a precursor to it. A tentative value of the energy required to planarize the fluorene backbone of (15.6,,2.5) kJ mol,1 monomer is suggested. Excitation spectra of PF6, PF7, PF8, and PF9 in extremely dilute (, 10,ng mL,1) solution show that beta phase can form reversibly in dilute solutions of PF7, PF8 and PF9, which is believed to be a result of chain collapse or well dispersed aggregates being present in solution from dilution of more concentrated solutions. PF7, PF8, and PF9 also form beta phase in thermally cycled solid films spin-cast from MCH. However, in the films the PF7 formed a larger fraction of beta phase than the PF9, in contrast to the case in solutions, because it is less likely that the close-packed chains in the solid state will allow the formation of planarized chains with the longer PF9 side chains. [source]

    Guest-Induced Chirality in the Ferrimagnetic Nanoporous Diamond Framework Mn3(HCOO)6,

    B. Zhang
    Abstract Chiral magnets are obtained by inclusion of chiral guest molecules into the channels of an achiral nanoporous ferrimagnet consisting of the Mn3(HCOO)6 (1) framework. Insertion of the R or the S enantiomer of 2-chloropropan-1-ol (CH3C*HClCH2OH) in the chiral pores of the previously emptied framework (space group P21/c) results in the two corresponding chiral solids (1R and 1S, space group P21), while insertion of a racemic mixture of the two enantiomers retains the achirality of the host for the meso solid (1RS, space group P21/c). The R guest is ordered in the M channels while the S guest is ordered in the P channels. In contrast, the R guests in the P channels and the S guests in the M channels are disordered on two crystallographic orientations. For the racemic mixture of the two enantiomers in 1RS, random disorder of guests in both channels is observed. Thus, the localization of the guest molecule depends on the nature of the surface to recognize the guest of a particular chirality. The guest inclusion compounds are thermally stable. The 1R and 1S compounds are optically active. All the compounds adopt a ferrimagnetic ground state. Compared to the host framework of 1 without guest, the Curie temperature decreases for both 1R and 1S but increases for 1RS. The additional interactions between the framework and the inserted guest alcohols strengthen the lattice via hydrogen bonds and other electrostatic forces, and it might account for the significant lowering of the lattice contribution as well as the magnetic component to the specific heat capacity upon guest loading. [source]

    Torsional Motion in (tert -Butyl)ammonium Hemispheraplexes: Rotational Barriers and Energy of Binding

    The ADPs (ADPs=atomic anisotropic displacement parameters) from the single-crystal X-ray studies of nine related TBA+ (TBA+=(tert -butyl)ammonium) hemispheraplexes are analyzed, and the results compared to the free energy of binding of this guest by the nine hosts. The lipophilic hosts (Fig.,1) were synthesized over a number of years, with increasing pre-organization for and specificity of binding. Structural studies for six of the complexes have been published, but the remaining three structures, including those of the strongest binders of TBA+, are disordered and have only now been completed. New area-detector data has been analyzed for the TBA+ClO complexes of 5 and of 8 at two temperatures, while the original data for 9,TBA+SCN, has been treated with a disorder model. In addition, improved models are presented for the complexes of 6 and 7. Methods for assessing the precision of the ADP analyses are discussed. Although most of the structures are imprecise, the TBA+ groups do demonstrate some of the characteristics of independent motion. The general trend in calculated libration amplitudes for the TBA+ group suggests that the guests with the greatest free energy of binding, and the shortest distances from N+ to the ligand plane, are those with the highest barriers to internal rotation. [source]

    Single-Molecule Spectroscopy for Plastic Electronics: Materials Analysis from the Bottom-Up

    ADVANCED MATERIALS, Issue 15 2010
    John M. Lupton
    Abstract , -conjugated polymers find a range of applications in electronic devices. These materials are generally highly disordered in terms of chain length and chain conformation, besides being influenced by a variety of chemical and physical defects. Although this characteristic can be of benefit in certain device applications, disorder severely complicates materials analysis. Accurate analytical techniques are, however, crucial to optimising synthetic procedures and assessing overall material purity. Fortunately, single-molecule spectroscopic techniques have emerged as an unlikely but uniquely powerful approach to unraveling intrinsic material properties from the bottom up. Building on the success of such techniques in the life sciences, single-molecule spectroscopy is finding increasing applicability in materials science, effectively enabling the dissection of the bulk down to the level of the individual molecular constituent. This article reviews recent progress in single molecule spectroscopy of conjugated polymers as used in organic electronics. [source]

    Localized electrical current propagation in anisotropically perturbed atmospheres

    T. I. ZohdiArticle first published online: 29 MAR 2010
    Abstract The trajectory of free atmospheric electrical currents, such as lightning and sparks, is strongly influenced by microscale events that occur at the current front. In particular, highly conductive pathways can occur at the free surface front due to dielectric breakdown. The specific directions of the local pathways are minutely perturbed, due to the gaseous, disordered, nature of the media at the small scale. This results in highly conductive, anisotropically perturbed, continuum-level properties at the electrical current front. In this work, a model is developed to investigate the role of the resulting anisotropically perturbed conductivity at the propagation front on the overall trajectory of free atmospheric electrical currents. The approach is to relate the electrical current velocity to the local anisotropic conductivity at the propagation front and the surrounding electric field. The conductive anisotropy is decomposed into an isotropic ,base state' and an anisotropic perturbation. The current trajectory is shown to be governed by a set of non-linear differential equations, for which a numerical solution scheme is developed. The difference between paths taken through anisotropically perturbed and isotropic media is analytically bounded and quantified numerically as a function of the magnitude of the anisotropic perturbation. The analysis and numerical experiments indicate that, in a statistical sense, the difference in the paths taken in anisotropically perturbed and isotropic media depends quasilinearly on the perturbation magnitude. Copyright 2010 John Wiley & Sons, Ltd. [source]

    Unraveling the mysteries of protein folding and misfolding

    IUBMB LIFE, Issue 12 2008
    Heath Ecroyd
    Abstract This mini-review focuses on the processes and consequences of protein folding and misfolding. The latter process often leads to protein aggregation and precipitation with the aggregates adopting either highly ordered (amyloid fibril) or disordered (amorphous) forms. In particular, the amyloid fibril is discussed because this form has gained considerable notoriety due to its close links to a variety of debilitating diseases including Alzheimer's, Parkinson's, Huntington's, and Creutzfeldt-Jakob diseases, and type-II diabetes. In each of these diseases a different protein forms fibrils, yet the fibrils formed have a very similar structure. The mechanism by which fibrils form, fibril structure, and the cytotoxicity associated with fibril formation are discussed. The generic nature of amyloid fibril structure suggests that a common target may be accessible to treat amyloid fibril-associated diseases. As such, the ability of some molecules, for example, the small heat-shock family of molecular chaperone proteins, to inhibit fibril formation is of interest due to their therapeutic potential. 2008 IUBMB IUBMB Life, 60(12): 769,774, 2008 [source]

    Observation of orientational disorder in the hexagonal stuffed tridymite Sr0.864Eu0.136Al2O4 by the maximum-entropy method

    H. Yamada
    The crystal structure of a strontium europium aluminate, Sr0.864Eu0.136Al2O4, with a novel hexagonal form was investigated by a combination of Rietveld analysis and the maximum-entropy method (MEM) with synchrotron X-ray powder diffraction data. The electron density image calculated by the MEM/Rietveld method revealed that the apical oxygen ion in the AlO4 tetrahedron has a broad distribution corresponding to an extraordinarily large atomic displacement parameter. This structure could be expressed by a split-atom model, with which the Rietveld refinement gave Rwp = 2.99% and RB = 4.16%. Subsequently, MEM-based pattern fitting (MPF) decreased the R factors to Rwp = 2.81% and RB = 2.34% and the electron density image clearly showed that the apical oxygen ions of the AlO4 tetrahedra are split over three sites around a threefold axis involving an elongated distribution of the residual O ions along the c axis. These results suggest that AlO4 tetrahedra in Sr0.864Eu0.136Al2O4 are orientationally disordered. [source]

    Teaching diffraction using computer simulations over the Internet

    Th. Proffen
    Computer simulations are a versatile tool to enhance the teaching of diffraction physics and related crystallographic topics to students of chemistry, materials science, physics and crystallography. Interactive computer simulations are presented, which have been added to a World Wide Web (WWW) based tutorial. A simple WWW interface is used to choose appropriate values for selected simulation parameters. The resulting structure and diffraction pattern are then plotted on the screen. Simulated structures range from a single atom to complex disordered or modulated structures. The simple interface requires no special computing knowledge and allows students to explore systematically the relationship between a real-space structure and the corresponding diffraction pattern. The large function set of the underlying simulation program (DISCUS) makes it easy to tailor the tutorial to a given syllabus by modifying or extending the current interactive examples. [source]

    Characterization of end-functionalized styrene,butadiene,styrene copolymers and their application in modified asphalt

    Qiang Wang
    Abstract End amino, carboxylic acid, and hydroxyl functionalized styrene,butadiene,styrene (SBS) triblock copolymers were prepared with 1,5-diazabicyclo[3.1.0]hexane, carbon dioxide, and epoxy ethane as capping agents, respectively. The effects of the end polar groups on the morphology and dynamic mechanical properties were investigated. Transmission electron microscopy images suggested that the group at the end of the polystyrene (PS) segment made the morphology of the PS domains disordered and incompact. Dynamic mechanical results showed that the storage and loss modulus increased after SBS was end-functionalized. End amino and carboxylic acid groups improved the compatibility and storage stability of SBS-modified asphalt. However, the effect of the end-hydroxyl group on the improvement of the storage stability of SBS-modified asphalt was not obvious. The differential scanning calorimetry analysis of SBS-modified asphalt further showed that the compatibility and storage stability of SBS-modified asphalt were improved by the attachment of amino or carboxylic acid groups through the anionic polymerization method. 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 8,16, 2007 [source]

    Television and attitudes toward mental health issues: Cultivation analysis and the third-person effect

    Donald L. Diefenbach
    A television content analysis and survey of 419 community respondents supports the hypothesis that media stereotypes affect public attitudes toward mental health issues. A content analysis of network, prime-time television demonstrates that portrayals are violent, false, and negative. The mentally disordered are portrayed as 10 times more likely to be a violent criminal than nonmentally disordered television characters. A survey demonstrates that as television viewing increases so does the belief among viewers that locating mental health services in residential neighborhoods will endanger the residents. Viewers who watch television news are less likely to support living next to someone who is mentally ill. The survey also tests the third-person effect, and finds that viewers believe television portrayals of mental illness affect others more than themselves. 2007 Wiley Periodicals, Inc. [source]



    Background/objective, Apoptosis is disordered in tumourigensis, however, the importance of apoptosis in relation to DNA damage created at the time of initiation by genotoxic carcinogens, i.e. the acute apoptotic response to genotoxic carcinogens (AARGC), has hardly been explored. p53 and APC are tumor suppressor genes known to be altered frequently in colon cancer, however, it remains unclear whether AARGC is dependent on the function of p53 or APC. p53 ,/,, p53 and APCMin/+ mice provide an excellent model to test the biological significance of AARGC in colon in terms of its ability to delete genetically damaged cells that might progress to cancer. Thus, we have tested the hypothesis that p53 and APC play a critical role in AARGC, by studying AARGC in p53+/, , p53 ,/, mice and APCMin/+0. Methods, p53 knockout mice were produced by breeding male p53+/, with female C57BL/J mice or interbreeding p53+/, mice. APCMin/+ mice were produced by breeding male APCMin/+ mice with female C57BL/J mice. Mice geno-typing were confirmed by PCR. At 10,12 weeks age, 44 mice were given a single subcutaneous azoxymethane (AOM 10 mg/kg) injection to induce AARGC, and killed 6 h later (the time of the maximal response). There were eight p53,/, mice, 11 p53+/, mice, nine p53+/+mice, 12 APCMin/+ mice, and six APC+/+ mice. Three p53,/, mice, four p53+/, mice, seven p53+/+ mice, two APCMin/+, and six APC+/+ mice without AOM injection were used as controls. Apoptosis in colon was measured by classic morphological H & E criteria. Results, In p53+/+ mice, AOM induced a significant increase in apoptosis (4.70 0.35, SEM, apoptotic cells per crypt column) in the distal colon, located almost exclusively in the proliferative compartment. In comparison to the pattern of apoptosis observed in the p53+/+ mice, the apoptotic response of p53,/, mice was almost nonexistent (0.12 0.06) while in p53+/, mice it was significantly suppressed by approximately 50% (2.26 0.28); P < 0.01. In contrast to the importance of p53 gene on AARGC, absence of the APC gene had no obvious effect on AARGC: APCMin/+ mice (5.07 0.30) and APC+/+ (5.50 0.33); P > 0.05. Conclusion, p53 function appears to be critically important for carcinogen-induced apoptosis in colon, while APC homeostasis appears not to be involved in this type of apoptosis. The loss of just one allele of p53, interferes with its function. Further studies are required to determine whether defective AARGC in p53 knockout mice puts them at increased risk of subsequent events in tumorigensis, and whether AARGC can be regulated by known protective agents. [source]

    Implicit Family Process Rules in Eating-Disordered and Non-Eating-Disordered Families

    Kyle S. Gillett
    Family environment has been shown to be one of the factors related to the presence of eating disorders among young-adult females. Clinical experience and theories about eating disorders postulate that implicit family rules are an intricate part of family process that may have a great effect on the creation and maintenance of such problems. This study compared implicit family process rules (specifically rules pertaining to kindness; expressiveness and connection; constraining thoughts, feelings, and self; inappropriate caretaking; and monitoring) in families with a young-adult female diagnosed with an eating disorder,either anorexia nervosa, bulimia nervosa, or eating disorder not otherwise specified,and families with a young-adult female without an eating disorder diagnosis. One hundred two families (51 eating disordered and 51 comparison) participated in the study. Mothers, fathers, young-adult female children, and siblings completed the Family Implicit Rules Profile (Harper, Stoll, & Larson, 2007). Results indicated that eating-disordered families are governed by a greater proportion of constraining family rules than are non-eating-disordered families. Additionally, eating-disordered youth reported a lower proportion of facilitative family rules and a higher proportion of constraining family rules than did parents and siblings. Theoretical, research, and clinical implications are discussed. [source]

    Folding transitions in calpain activator peptides studied by solution NMR spectroscopy

    Orsolya Toke
    Abstract Calpastatin, the endogenous inhibitor of calpain, a cysteine protease in eukaryotic cells, is an intrinsically unstructured protein, which upon binding to the enzyme goes through a conformational change. Peptides calpA (SGKSGMDAALDDLIDTLGG) and calpC (SKPIGPDDAIDALSSDFTS), corresponding to the two conserved subdomains of calpastatin, are known to activate calpain and increase the Ca2+ sensitivity of the enzyme. Using solution NMR spectroscopy, here we show that calpA and calpC are disordered in water but assume an ,-helical conformation in 50% CD3OH. The position and length of the helices are in agreement with those described in the literature for the bound state of the corresponding segments of calpastatin suggesting that the latter might be structurally primed for the interaction with its target. According to our data, the presence of Ca2+ induces a backbone rearrangement in the peptides, an effect that may contribute to setting the fine conformational balance required for the interaction of the peptides with calpain. Copyright 2009 European Peptide Society and John Wiley & Sons, Ltd. [source]

    Peptide vector for gene delivery with high affinity for phosphatidylserine

    Shinichi Kuriyama
    Abstract Since phosphatidylserine (PS) is known to translocate to the external face of the plasma membrane when the cell membrane becomes disordered, we decided to focus our attention on PS as a target molecule for gene delivery. In this paper, the novel peptide Td3701 was designed, synthesized, and characterized for its physico-chemico-biological properties. Td3701 simultaneously exhibited both characters as a DNA carrier and a sensor probe for active targeting, which seemed to be triggered by structural changes in the presence of PS. This is a very unique character among nonviral vectors, and it is believed that Td3701 could be used for selective gene delivery. Copyright 2006 European Peptide Society and John Wiley & Sons, Ltd. [source]

    Informatic calibration of a materials properties database for predictive assessment of mechanically activated disordering potential for small molecule organic solids

    Yannan Lin
    Abstract The potential for small molecule organic crystalline materials to become disordered as a result of high shear mechanical processing was investigated. A data-driven model was generated from a database of critical materials properties, which were expected to correlate with the potential of a small molecule organic crystalline solid to become fully disordered by the application of mechanical energy. The model was compared with a previously published disordering model based on fundamental thermodynamic relationships. Samples of 23 crystalline solids were subjected to extensive comminution under controlled temperature conditions; powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) were used to confirm disordering. Logistic regression was used to investigate the significance of each materials property with respect to the prediction of disordering potential. Seven materials properties (glass transition temperature, melting temperature, heat of fusion, crystallographic density, Young's modulus, molar volume and attachment energy) were identified as having a significant correlation with the potential for material disordering. Stepwise multivariate logistic regression was used to further assess the correlation between disordering potential and each of the seven properties. A linear probability model based on two materials properties (glass transition temperature and molar volume) was developed for the prediction of disordering potential. 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:2696,2708, 2009 [source]