bluuebunny/crossref_metadata_2025 huggingface dataset:
Micro-Raman study of the microheterogeneity in the MA-MC phase transition in 0.67PbMg1/3Nb2/3O3-0.33PbTiO3 single crystal
Authors: Yang Y. , Zhang L. Y. , Zhu K. , Liu Y. L.
Published: April 2011

Polarized Raman spectroscopy has been employed to investigate the evolution of the microstructure of 0.67PbMg1/3Nb2/3O3-0.33PbTiO3 (PMN-33%PT) single crystal in the temperature range from −195 to 300 °C. The MA-MC-cubic transition sequence was observed in the microareas with MA-type (space group Cm) and MC-type (space group Pm) monoclinic structures. Interestingly, the MA-MC phase transition temperature exhibited remarkable microareal dependence due to the spatial inhomogeneity of polar nanoregions (PNRs). The MC-cubic phase transition took place at 155 °C in both microareas, which consisted well with previous reports. These results reveal that the phase transition in PMN-33%PT single crystal is closely related with the thermal dynamics of PNRs, which will be useful for understanding the microheterogeneity in this compound.
Tunable optical and electronic properties of Si nanowires by electric bias
Authors: Zhang R. Q. , Gao N. , Lian J. S. , Jiang Q
Published: April 2011

Using density functional theory with Hamprecht–Cohen–Tozer–Handy (HCTH) functional, we demonstrate that the electric bias V applied on the surfaces of 〈112〉 Si nanowires (SiNWs) can modulate longitudinal (bandgap Eg) and transverse (indirect to direct bandgap transition) variations of electronic band structures while the latter is direction-dependent and occurs only when V is applied on (110) layers. The physical mechanism of the variations of electronic band structures is essentially the electron redistribution in different layers. Also the semiconductor-to-metal transition can be realized where SiNWs go into metallic regime under suitable values of electric bias. The density of states near the Fermi level increases with increasing V after a semiconductor to metal transition occurs in SiNWs. These results extend the application of SiNWs in optical and electronic nanodevices.
Quantum mechanical embedding theory based on a unique embedding potential
Authors: Huang Chen , Pavone Michele , Carter Emily A.
Published: April 2011

We remove the nonuniqueness of the embedding potential that exists in most previous quantum mechanical embedding schemes by letting the environment and embedded region share a common embedding (interaction) potential. To efficiently solve for the embedding potential, an optimized effective potential method is derived. This embedding potential, which eschews use of approximate kinetic energy density functionals, is then used to describe the environment while a correlated wavefunction (CW) treatment of the embedded region is employed. We first demonstrate the accuracy of this new embedded CW (ECW) method by calculating the van der Waals binding energy curve between a hydrogen molecule and a hydrogen chain. We then examine the prototypical adsorption of CO on a metal surface, here the Cu(111) surface. In addition to obtaining proper site ordering (top site most stable) and binding energies within this theory, the ECW exhibits dramatic changes in the p-character of the CO 4σ and 5σ orbitals upon adsorption that agree very well with x-ray emission spectra, providing further validation of the theory. Finally, we generalize our embedding theory to spin-polarized quantum systems and discuss the connection between our theory and partition density functional theory.
Conditions for efficient and stable ion acceleration by moderate circularly polarized laser pulses at intensities of 1020 W/cm2
Authors: Qiao B. , Zepf M. , Gibbon P. , Borghesi M. , Dromey B. , Kar S. , Schreiber J. , Geissler M.
Published: April 2011

Conditions for efficient and stable ion radiation pressure acceleration (RPA) from thin foils by circularly polarized laser pulses at moderate intensities are theoretically and numerically investigated. It is found that the unavoidable decompression of the co-moving electron layer in Light-Sail RPA leads to a change of the local electrostatic field from a “bunching” to a “debunching” profile, ultimately resulting in premature termination of ion acceleration. One way to overcome this instability is the use of a multispecies foil where the high-Z ions act as a sacrificial species to supply excess co-moving electrons for preserving stable acceleration of the lower-Z ion species. It is shown by 2D particle-in-cell simulations that 100 MeV/u monoenergetic C6+ ion beams are produced by irradiation of a Cu–C-mixed foil with laser pulses at intensities 5 × 1020 W/cm2, which can be easily achieved by current day lasers.
Field emission from single and few-layer graphene flakes
Authors: Santandrea S. , Giubileo F. , Grossi V. , Santucci S. , Passacantando M. , Schroeder T. , Lupina G. , Di Bartolomeo A.
Published: April 2011

We report the observation and characterization of field emission current from individual single- and few-layer graphene flakes laid on a flat SiO2/Si substrate. Measurements were performed in a scanning electron microscope chamber equipped with nanoprobes which allowed local measurement of the field emission current. We achieved field emission currents up to 1 μA from the flat part of graphene flakes at applied fields of few hundred volt per micrometer. We found that the emission process is stable over a period of several hours and that it is well described by a Fowler–Nordheim model for currents over five orders of magnitude.
Ab initio potential and dipole moment surfaces for water. II. Local-monomer calculations of the infrared spectra of water clusters
Authors: Wang Yimin , Bowman Joel M.
Published: April 2011

We employ recent flexible ab initio potential energy and dipole surfaces [Y. Wang, X. Huang, B. C. Shepler, B. J. Braams, and J. M. Bowman, J. Chem. Phys. 134, 094509 (2011)10.1063/1.3554905] to the calculation of IR spectra of the intramolecular modes of water clusters. We use a quantum approach that begins with a partitioned normal-mode analysis of perturbed monomers, and then obtains solutions of the corresponding Schrödinger equations for the fully coupled intramolecular modes of each perturbed monomer. For water clusters, these modes are the two stretches and the bend. This approach is tested against benchmark calculations for the water dimer and trimer and then applied to the water clusters (H2O)n for n = 6–10 and n = 20. Comparisons of the spectra are made with previous ab initio harmonic and empirical potential calculations and available experiments.
Note: Ultrasonic gas flowmeter based on optimized time-of-flight algorithms
Authors: Wang X. F. , Tang Z. A.
Published: April 2011

A new digital signal processor based single path ultrasonic gas flowmeter is designed, constructed, and experimentally tested. To achieve high accuracy measurements, an optimized ultrasound driven method of incorporation of the amplitude modulation and the phase modulation of the transmit–receive technique is used to stimulate the transmitter. Based on the regularities among the received envelope zero-crossings, different received signal's signal-to-noise ratio situations are discriminated and optional time-of-flight algorithms are applied to take flow rate calculations. Experimental results from the dry calibration indicate that the designed flowmeter prototype can meet the zero-flow verification test requirements of the American Gas Association Report No. 9. Furthermore, the results derived from the flow calibration prove that the proposed flowmeter prototype can measure flow rate accurately in the practical experiments, and the nominal accuracies after FWME adjustment are lower than 0.8% throughout the calibration range.
A new route to graphene layers by selective laser ablation
Authors: Dhar S. , Barman A. Roy , Ni G. X. , Wang X. , Xu X. F. , Zheng Y. , Tripathy S. , Ariando  , Rusydi A. , Loh K. P. , Rubhausen M. , Neto A. H. Castro , Őzyilmaz B. , Venkatesan T.
Published: April 2011

Selectively creating regions of spatially varying thickness may enable the utilization of the electronic properties of N-layer (N=1 or more) graphene and other similar layered materials (e.g., topological insulators or layered superconductors) for novel devices and functionalities on a single chip. The ablation threshold energy density increases dramatically for decreasing layer numbers of graphene originating from the dimensional crossover of the specific heat. For the 2D regime of graphite (up to N≈7) the dominant flexural mode specific heat (due to its N-1 dependence) gives rise to a strong layer number-dependence on the pulsed laser ablation threshold energy density, while for 3D regime (N>>7) the ablation threshold saturates due to dominant acoustic mode specific heat. As a result, several energy density windows exist between the minimum energy densities that are required for ablating single, bi, or more layers of graphene, allowing layer number selectivity.
Markov model of smoking cessation
Authors: Killeen Peter R.
Published: April 2011

Survival functions from smoking cessation interventions are described by a three-state Markov model. On quitting, smokers transit through a state of withdrawal characterized by a high rate of relapse, and then into a more secure state of long-term abstinence. The Markov model embodies the dynamic nature of the cessation/relapse process; it permits stronger inference to long-term abstinence rates, provides measures of treatment efficacy, describes the outcomes of new quit attempts, and suggests mechanisms for the survival process.
Growth-factor receptor-bound protein-2 (Grb2) signaling in B cells controls lymphoid follicle organization and germinal center reaction
Authors: Jang Ihn Kyung , Cronshaw Darran G. , Xie Luo-kun , Fang Guoqiang , Zhang Jinping , Oh Hyunju , Fu Yang-Xin , Gu Hua , Zou Yongrui
Published: April 2011

Grb2 (growth-factor receptor-bound protein-2) is a signaling adaptor that interacts with numerous receptors and intracellular signaling molecules. However, its role in B-cell development and function remains unknown. Here we show that ablation of Grb2 in B cells results in enhanced B-cell receptor signaling; however, mutant B cells do not form germinal centers in the spleen after antigen stimulation. Furthermore, mutant mice exhibit defects in splenic architecture resembling that observed in B-cell–specific lymphotoxin-β–deficient mice, including disruption of marginal zone and follicular dendritic cell networks. We find thatgrb2−/−B cells are defective in lymphotoxin-β expression. Although lymphotoxin can be up-regulated by chemokine CXCL13 and CD40 ligand stimulation in wild-type B cells, elevation of lymphotoxin expression ingrb2−/−B cells is only induced by anti-CD40 but not by CXCL13. Our results thus define Grb2 as a nonredundant regulator that controls lymphoid follicle organization and germinal center reaction. Loss of Grb2 has no effect on B-cell chemotaxis to CXCL13, indicating that Grb2 executes this function by connecting the CXCR5 signaling pathway to lymphotoxin expression but not to chemotaxis.
Serine/threonine kinase gene
Stpk-V
, a key member of powdery mildew resistance gene
Pm21
, confers powdery mildew resistance in wheat
Authors: Cao Aizhong , Xing Liping , Wang Xiaoyun , Yang Xueming , Wang Wei , Sun Yulei , Qian Chen , Ni Jinlong , Chen Yaping , Liu Dajun , Wang Xiue , Chen Peidu
Published: April 2011

Powdery mildew resistance gene
Pm21
, located on the chromosome 6V short arm of
Haynaldia villosa
and transferred to wheat as a 6VS·6AL translocation (T6VS·6AL), confers durable and broad-spectrum resistance to wheat powdery mildew.
Pm21
has become a key gene resource for powdery mildew resistance breeding all over the world. In China, 12 wheat varieties containing
Pm21
have been planted on more than 3.4 million hectares since 2002.
Pm21
has been intractable to molecular genetic mapping because the 6VS does not pair and recombine with the 6AS. Moreover, all known accessions of
H. villosa
are immune to powdery mildew fungus.
Pm21
is still defined by cytogenetics as a locus. In the present study, a putative serine and threonine protein kinase gene
Stpk-V
was cloned and characterized with an integrative strategy of molecular and cytogenetic techniques.
Stpk-V
is located on the
Pm21
locus. The results of a single cell transient expression assay showed that
Stpk-V
could decrease the haustorium index dramatically. After the
Stpk-V
was transformed into a susceptible wheat variety Yangmai158, the characterized transgenic plants showed high and broad-spectrum powdery mildew resistance similar to T6VS·6AL. Silencing of the
Stpk-V
by virus-induced gene silencing in both T6VS·6AL and
H. villosa
resulted in their increased susceptibility.
Stpk-V
could be induced by
Bgt
and exogenous H
2
O
2
, but it also mediated the increase of endogenous H
2
O
2
, leading to cell death and plant resistance when the plant was attacked by
Bgt
.
Crystal structures of the endoplasmic reticulum aminopeptidase-1 (ERAP1) reveal the molecular basis for N-terminal peptide trimming
Authors: Kochan Grazyna , Krojer Tobias , Harvey David , Fischer Roman , Chen Liye , Vollmar Melanie , von Delft Frank , Kavanagh Kathryn L. , Brown Matthew A. , Bowness Paul , Wordsworth Paul , Kessler Benedikt M. , Oppermann Udo
Published: April 2011

Endoplasmatic reticulum aminopeptidase 1 (ERAP1) is a multifunctional enzyme involved in trimming of peptides to an optimal length for presentation by major histocompatibility complex (MHC) class I molecules. Polymorphisms in ERAP1 have been associated with chronic inflammatory diseases, including ankylosing spondylitis (AS) and psoriasis, and subsequent in vitro enzyme studies suggest distinct catalytic properties of ERAP1 variants. To understand structure-activity relationships of this enzyme we determined crystal structures in open and closed states of human ERAP1, which provide the first snapshots along a catalytic path. ERAP1 is a zinc-metallopeptidase with typical H-E-X-X-H-(X)
18
-E zinc binding and G-A-M-E-N motifs characteristic for members of the gluzincin protease family. The structures reveal extensive domain movements, including an active site closure as well as three different open conformations, thus providing insights into the catalytic cycle. A K
528
R mutant strongly associated with AS in GWAS studies shows significantly altered peptide processing characteristics, which are possibly related to impaired interdomain interactions.
Thermal dissipation media for high power electronic devices using a carbon nanotube-based composite
Authors: Bui Hung Thang , Nguyen Van Chuc , Pham Van Trinh , Ngo Thi Thanh Tam , Phan Ngoc Minh
Published: April 2011

Challenges in the thermal dissipation of an electronic package arise from the continuous increase in power density of higher-power devices. Carbon nanotubes (CNTs) are known as the highest thermal conductivity material (2000 W 
mK
−1). This excellent thermal property suggests an approach in applying the CNTs in thermal dispersion materials to solve the aforementioned problems. In this work, we present an effect of thermal dissipation of the CNTs in the high-brightness light emitting diode (HB-LED) and micro-processor. For the thermal dissipation of the HB-LED, a vertically aligned carbon nanotube (VA-CNT) film on a Cu substrate was applied. Meanwhile, for the thermal dissipation of a micro-processor, the composite of commercial thermal paste/CNTs was used instead of the VA-CNTs. The experimental and simulation results have confirmed the advantages of the VA-CNT film and thermal paste/CNT composite as excellent thermal dissipation media for HB-LEDs, μ-processors and other high power electronic devices.
On stably free modules over Laurent polynomial rings
Authors: Abedelfatah Abed
Published: April 2011

We prove constructively that for any finite-dimensional commutative ring

R
R

and

n
≥
dim
⁡
(
R
)
+
2

n\geq \dim (R)+2

, the group

E

n

(
R
[
X
,

X

−
1

]
)

\mathrm {E}_{n}(R[X,X^{-1}])

acts transitively on

U
m

n

(
R
[
X
,

X

−
1

]
)

\mathrm {Um}_{n}(R[X,X^{-1}])

. In particular, we obtain that for any finite-dimensional ring

R
R

, every finitely generated stably free module over

R
[
X
,

X

−
1

]

R[X,X^{-1}]

of rank

>
dim
⁡
R

>\dim R

is free; i.e.,

R
[
X
,

X

−
1

]

R[X,X^{-1}]

is

(
dim
⁡
R
)

(\dim R)

-Hermite.
A note on composition operators acting on holomorphic Sobolev spaces
Authors: Choe Boo Rim , Koo Hyungwoon , Smith Wayne
Published: April 2011

A holomorphic self-map

φ
\varphi

of the unit disk is constructed such that the composition operator induced by

φ
\varphi

is bounded on the Hardy-Sobolev space

H
2
1

H^1_2

of order

2
2

as well as on the ordinary holomorphic Lipschitz space

Lip

1

\textrm {Lip}_1

but unbounded on the Zygmund class

Λ
1

\Lambda _1

. Among these three function spaces we have embedding relations

H
2
1

⊂

Lip

1

⊂

Λ
1

H^1_2\subset \textrm {Lip}_1\subset \Lambda _1

. So, the main points here are that our construction provides a composition operator which is bounded on smaller spaces, but not on a larger space and that all the function spaces involved are standard ones.
The singleDrosophilaZO-1 protein Polychaetoid regulates embryonic morphogenesis in coordination with Canoe/afadin and Enabled
Authors: Choi Wangsun , Jung Kuo-Chen , Nelson Kevin S. , Bhat Manzoor A. , Beitel Greg J. , Peifer Mark , Fanning Alan S.
Published: April 2011

Adherens and tight junctions play key roles in assembling epithelia and maintaining barriers. In cell culture zonula occludens (ZO)–family proteins are important for assembly/maturation of both tight and adherens junctions (AJs). Genetic studies suggest that ZO proteins are important during normal development, but interpretation of mouse and fly studies is limited by genetic redundancy and/or a lack of null alleles. We generated null alleles of the single Drosophila ZO protein Polychaetoid (Pyd). Most embryos lacking Pyd die with striking defects in morphogenesis of embryonic epithelia including the epidermis, segmental grooves, and tracheal system. Pyd loss does not dramatically affect AJ protein localization or initial localization of actin and myosin during dorsal closure. However, Pyd loss does affect several cell behaviors that drive dorsal closure. The defects, which include segmental grooves that fail to retract, a disrupted leading edge actin cable, and reduced zippering as leading edges meet, closely resemble defects in canoe zygotic null mutants and in embryos lacking the actin regulator Enabled (Ena), suggesting that these proteins act together. Canoe (Cno) and Pyd are required for proper Ena localization during dorsal closure, and strong genetic interactions suggest that Cno, Pyd, and Ena act together in regulating or anchoring the actin cytoskeleton during dorsal closure.
Reliability of the Nursing Home Survey Process: A Simultaneous Survey Approach
Authors: Lee Robert H. , Gajewski Byron J. , Thompson Sarah
Published: April 2011

Purpose: We designed this study to examine the reliability of the nursing home survey process in the state of Kansas using regular and simultaneous survey teams. In particular, the study examined how two survey teams exposed to the same information at the same time differed in their interpretations. Design and Methods: The protocol for simultaneous surveys consists of having one in-region and one out-of-region team survey a facility together. Results: The regular and simultaneous survey teams generally agreed about the number of deficiencies. The intraclass correlation coefficient was 0.87 for total deficiencies and 0.76 for deficiencies with scores of G or higher. But in a substantial number of instances the teams did not agree about the scope and severity of the deficiency or about what regulation the nursing home had breached. Implications: The survey process is reliable when assessing aggregate results, but it is only moderately reliable when examining individual citations. Stakeholders (i.e., consumers, policy makers, nursing home administrators) should be aware of the limitations of the survey process. It needs to be modified to reduce variability.
Long-Term Effects of a Stage-Based Intervention for Changing Exercise Intentions and Behavior in Older Adults
Authors: Greaney Mary L. , Riebe Deborah , Ewing Garber Carol , Rossi Joseph S. , Lees Faith D. , Burbank Patricia A. , Nigg Claudio R. , Ferrone Christine L. , Clark Phillip G.
Published: April 2011

Purpose:  We examined the efficacy of an intervention tailored to the individual's stage of change for exercise adoption on exercise stage of change, physical activity, and physical function in community-dwelling older adults. Design and Methods: We randomized participants to a print and telephone intervention or a contact comparison group. Through the use of longitudinal analyses we examined the intervention's effectiveness in promoting stage progression, altering decisional balance and the processes of change, increasing self-efficacy and physical activity, and improving physical function among older adults who completed the 24-month study (N = 966). We conducted similar analyses that excluded individuals who were in maintenance at baseline and 24 months. Results:  At the end of the study, there were no differences in stage progression, self-efficacy, decisional balance, the processes of change, physical activity, or physical function by intervention assignment. When the analyses excluded those participants (n = 358) who were in the maintenance stage for exercise throughout the intervention, we found that, compared with the comparison group, a greater proportion of individuals who received the exercise intervention progressed in stage by 24 months. Conversely, more individuals in the comparison group remained stable or regressed in stage compared with the intervention group. Implications: Results indicate that a tailored intervention is effective in increasing motivational readiness for exercise in individuals who were in stages of change other than maintenance.
Lack of transmission of a human influenza virus with avian receptor specificity between ferrets is not due to decreased virus shedding but rather a lower infectivity in vivo
Authors: Roberts Kim L. , Shelton Holly , Scull Margaret , Pickles Raymond , Barclay Wendy S.
Published: April 2011

Influenza virus attaches to host cells by sialic acid (SA). Human influenza viruses show preferential affinity for α2,6-linked SA, whereas avian influenza viruses bind α2,3-linked SA. In this study, mutation of the haemagglutinin receptor-binding site of a human H3N2 influenza A virus to switch binding to α2,3-linked SA did not eliminate infection of ferrets but prevented transmission, even in a co-housed model. The mutant virus was shed from the noses of ferrets directly inoculated with virus in the same amounts and for the same length of time as wild-type virus. Mutant virus infection was localized to the same anatomical regions of the upper respiratory tract of directly inoculated animals. Interestingly, wild-type virus was more readily neutralized than the mutant virus in vitro by ferret nasal washes containing mucus. Moreover after inoculation of equal doses, the mutant virus grew poorly in ex vivo ferret nasal turbinate tissue compared with wild-type virus. The dose of mutant virus required to establish infection in the directly inoculated ferrets was 40-fold higher than for wild-type virus. It was concluded that minimum infectious dose is a predictor of virus transmissibility and it is suggested that, as virus passes from one host to another through stringent environmental conditions, viruses with a preference for α2,3-linked SA are unlikely to inoculate a new mammalian host in sufficient quantities to initiate a productive infection.
Staufen 2 regulates mGluR long-term depression and Map1b mRNA distribution in hippocampal neurons
Authors: Lebeau Geneviève , Miller Linda C. , Tartas Maylis , McAdam Robyn , Laplante Isabel , Badeaux Frédérique , DesGroseillers Luc , Sossin Wayne S. , Lacaille Jean-Claude
Published: April 2011

The two members of the Staufen family of RNA-binding proteins, Stau1 and Stau2, are present in distinct ribonucleoprotein complexes and associate with different mRNAs. Stau1 is required for protein synthesis–dependent long-term potentiation (L-LTP) in hippocampal pyramidal cells. However, the role of Stau2 in synaptic plasticity remains unexplored. We found that unlike Stau1, Stau2 is not required for L-LTP. In contrast, Stau2, but not Stau1, is necessary for DHPG-induced protein synthesis-dependent long-term depression (mGluR-LTD). While Stau2 is involved in early development of spines, its down-regulation does not alter spine morphology or spontaneous miniature synaptic activity in older cultures where LTD occurs. In addition, Stau2, but not Stau1, knockdown reduces the dendritic localization of Map1b mRNA, a specific transcript involved in mGluR-LTD. Moreover, mGluR stimulation with DHPG induces Map1b, but not Map2, mRNA dissociation from mRNA granules containing Stau2 and the ribosomal protein P0. This dissociation was not observed in cells in which Stau2 was depleted. Finally, Stau2 knockdown reduces basal Map1b protein expression in dendrites and prevents DHPG-induced increases in dendritic Map1b protein level. We suggest a role for Stau2 in the generation and regulation of Map1b mRNA containing granules that are required for mGluR-LTD.
Cell Wall Integrity Controls Root Elongation via a General 1-Aminocyclopropane-1-Carboxylic Acid-Dependent, Ethylene-Independent Pathway
Authors: Tsang Dat L. , Edmond Clare , Harrington Jennifer L. , Nühse Thomas S.
Published: April 2011

Cell expansion in plants requires cell wall biosynthesis and rearrangement. During periods of rapid elongation, such as during the growth of etiolated hypocotyls and primary root tips, cells respond dramatically to perturbation of either of these processes. There is growing evidence that this response is initiated by a cell wall integrity-sensing mechanism and dedicated signaling pathway rather than being an inevitable consequence of lost structural integrity. However, the existence of such a pathway in root tissue and its function in a broader developmental context have remained largely unknown. Here, we show that various types of cell wall stress rapidly reduce primary root elongation in Arabidopsis (Arabidopsis thaliana). This response depended on the biosynthesis of 1-aminocyclopropane-1-carboxylic acid (ACC). In agreement with the established ethylene signaling pathway in roots, auxin signaling and superoxide production are required downstream of ACC to reduce elongation. However, this cell wall stress response unexpectedly does not depend on the perception of ethylene. We show that the short-term effect of ACC on roots is partially independent of its conversion to ethylene or ethylene signaling and that this ACC-dependent pathway is also responsible for the rapid reduction of root elongation in response to pathogen-associated molecular patterns. This acute response to internal and external stress thus represents a novel, noncanonical signaling function of ACC.
Small-angle scattering from spindle-shaped colloidal hematite particles in external magnetic fields
Authors: Märkert Christian , Fischer Birgit , Wagner Joachim
Published: April 2011

In the presence of phosphate anions, spindle-shaped mesoscale hematite particles can be preparedviacontrolled precipitation of iron(III) chloride. The aspect ratio of the particles is determined by the concentration of phosphate anions selectively covering specific crystal surfaces and thus enabling anisotropic growth of the particles. The scattering function for suspensions of polydisperse spindles is derived and used to analyse the small-angle scattering resulting from these particles. In the presence of an external magnetic field, the particles align perpendicular to the field direction as a result of the negative anisotropy of their magnetic susceptibility \Delta\chi. Hereby, an isotropic–nematic phase transition can be induced in external magnetic fields.
StressTextureCalculator: a software tool to extract texture, strain and microstructure information from area-detector measurements
Authors: Randau C. , Garbe U. , Brokmeier H.-G.
Published: April 2011

Modern materials science diffractometers are generally equipped with area detectors that allow a high time efficiency to be achieved by simultaneously collecting the scattering pattern over large angular regions. These area-detector-based instruments, however, produce a huge amount of data, especially if they are located at large-scale neutron or synchrotron sources. The softwareStressTextureCalculator(STeCa) was designed to facilitate fast, easy and automated access to such area-detector data. Its outstanding features are direct calculation of diffraction patterns from different types of area-detector measurements, automatic data treatment and peak fitting using several implemented fit options. The resulting information on intensity, peak shift and broadening can then be exported into several data formats. These in turn can be used as input for a wide range of texture, stress and microstructure analysis software packages without additional prior treatment.
Arabidopsis thaliana cdd1 mutant uncouples the constitutive activation of salicylic acid signalling from growth defects
Authors: SWAIN SWADHIN , ROY SHWETA , SHAH JYOTI , VAN WEES SASKIA , PIETERSE CORNÉ M. , NANDI ASHIS K.
Published: April 2011

Arabidopsis genotypes with a hyperactive salicylic acid‐mediated signalling pathway exhibit enhanced disease resistance, which is often coupled with growth and developmental defects, such as dwarfing and spontaneous necrotic lesions on the leaves, resulting in reduced biomass yield. In this article, we report a novel recessive mutant of Arabidopsis, cdd1 (constitutive defence without defect in growth and development1), that exhibits enhanced disease resistance associated with constitutive salicylic acid signalling, but without any observable pleiotropic phenotype. Both NPR1 (NON‐EXPRESSOR OF PATHOGENESIS‐RELATED GENES1)‐dependent and NPR1‐independent salicylic acid‐regulated defence pathways are hyperactivated in cdd1 mutant plants, conferring enhanced resistance against bacterial pathogens. However, a functional NPR1 allele is required for the cdd1‐conferred heightened resistance against the oomycete pathogen Hyaloperonospora arabidopsidis. Salicylic acid accumulates at elevated levels in cdd1 and cdd1 npr1 mutant plants and is necessary for cdd1‐mediated PR1 expression and disease resistance phenotypes. In addition, we provide data which indicate that the cdd1 mutation negatively regulates the npr1 mutation‐induced hyperactivation of ethylene/jasmonic acid signalling.
Durable broad‐spectrum powdery mildew resistance in pea er1 plants is conferred by natural loss‐of‐function mutations in PsMLO1
Authors: HUMPHRY MATT , REINSTÄDLER ANJA , IVANOV SERGEY , BISSELING TON , PANSTRUGA RALPH
Published: April 2011

Loss‐of‐function alleles of plant‐specific MLO (Mildew Resistance Locus O) genes confer broad‐spectrum powdery mildew resistance in monocot (barley) and dicot (Arabidopsis thaliana, tomato) plants. Recessively inherited powdery mildew resistance in pea (Pisum sativum) er1 plants is, in many aspects, reminiscent of mlo‐conditioned powdery mildew immunity, yet the underlying gene has remained elusive to date. We used a polymerase chain reaction (PCR)‐based approach to amplify a candidate MLO cDNA from wild‐type (Er1) pea. Sequence analysis of the PsMLO1 candidate gene in two natural er1 accessions from Asia and two er1‐containing pea cultivars with a New World origin revealed, in each case, detrimental nucleotide polymorphisms in PsMLO1, suggesting that PsMLO1 is Er1. We corroborated this hypothesis by restoration of susceptibility on transient expression of PsMLO1 in the leaves of two resistant er1 accessions. Orthologous legume MLO genes from Medicago truncatula and Lotus japonicus likewise complemented the er1 phenotype. All tested er1 genotypes showed unaltered colonization with the arbuscular mycorrhizal fungus, Glomus intraradices, and with nitrogen‐fixing rhizobial bacteria. Our data demonstrate that PsMLO1 is Er1 and that the loss of PsMLO1 function conditions durable broad‐spectrum powdery mildew resistance in pea.
Breakdown of teenage placements in Danish out‐of‐home care
Authors: Olsson Martin , Egelund Tine , Høst Anders
Published: April 2011

This study deals with the problem of breakdown in out‐of‐home placements for Danish teenagers. How often are these placements prematurely terminated against the requests and intentions of the child welfare authorities? Which factors seem to increase and decrease placement breakdown? The sample consists of 225 youths and 367 placements during the years 2004–2008. Among the 225 youths, 44% experienced a breakdown, and 33% of the 367 placements ended with a breakdown. A large proportion of the placement breakdowns (20%) occurred before 4 months, and within the first year, 62% of the placement breakdowns had taken place. Replacements took place in 61% of all placement breakdowns. The analysis showed that type of placement and number of youth at the same placement had significant association to placement breakdown, but variables based on the social worker's clinical assessment showed no association to breakdown. However, while the logistic regression model was significant, it explained only 6% of the variance. Earlier studies have indicated that breakdown is a substantial problem of child welfare in several other western countries, Denmark is no exception. These corresponding breakdown rates point out that no child welfare system yet have found a method to reduce breakdown substantially.
Investigating the long‐term effects of a psychiatric rehabilitation programme for persons with serious mental illness in the community: a follow‐up study
Authors: Luk Andrew L
Published: April 2011

Aims and objectives.  This is a follow‐up study to investigate the long‐term effects of a holistic care programme for the rehabilitation of persons with serious mental illness. Perception of help from the programme and factors relating to the outcomes of the programme will also be studied.

Background.  This psychiatric rehabilitation programme in Hong Kong adopts a self‐help group (SHG) approach with holistic care emphasising on the physical, psychological, social and spiritual functioning of the programme participants.

Design.  A quantitative approach using a set of self‐administered questionnaires was adopted.

Method.  Data were compared with a quasi‐experimental study conducted in 2003 by Luk and Shek involving an experimental group and a control group.

Results.  All the outcome measures of participants were similar to that of the experimental group found in last study. When compared with the control group, it was found that participants had more hope than the control subjects. Help perceived from the programme included support, encouragement, enhancement of self‐confidence, spiritual assistance and reflection of values. Having a job is found to be a key factor relating to the outcomes of the programme participants.

Conclusions.  The programme is effective to provide some positive changes to its participants. Help is perceived by most participants and the programme is also useful to provide mutual support to participants in maintaining a job in the community, which is a paramount factor for rehabilitation.

Relevance to clinical practice.  A partnership model in SHG seems to be successful in providing support for the rehabilitation of persons with serious mental illness. Spiritual element should be incorporated into psychiatric rehabilitation programme to instil hope and meaningfulness of life. Nurses should be better educated in providing holistic care to individual clients and to a group.
Dying well: factors that influence the provision of good end‐of‐life care for older people in acute and long‐stay care settings in Ireland
Authors: Casey Dympna , Murphy Kathy , Ni Leime Aine , Larkin Philip , Payne Sheila , Froggatt Katherine A , O’Shea Eamon
Published: April 2011

Aim.  The aim of this study was to explore key stakeholders and direct care managers’ perspectives on the current provision of end‐of‐life care for older people in acute and long‐stay care settings in Ireland and to construct a model of these.

Background.  Although the literature reveals a number of factors that impact on end‐of‐life care, no study has examined staff perceptions concerning the provision of good end‐of‐life care for older people in an Irish context.

Design.  Grounded theory was used. Semi‐structured interviews were employed to collect data between 2007–2008.

Method.  A purposive sample of 33 staff involved in the delivery of end‐of‐life care to older people working in six sites were selected.

Results.  Factors that influence provision of end‐of‐life care in Ireland were identified. The core category was ‘dying well’. The potential to ‘die well’ was influenced by three factors, namely philosophy, culture and organisation of care, knowing the person and physical environment and resources.

Conclusions.  People are living longer consequently acute and long‐stay care setting will increasingly become places where older people die. This study identified the factors that influence the provision of good end‐of‐life care for older people. Mobilising resources to ensure that these factors are considered is crucial to ensuring that regardless of where older people die in Ireland, they will receive the highest standard of care that nurses can provide.

Relevance to practice.  Understanding the factors that influence the provision of end‐of‐life care in acute and long‐stay facilities in Ireland can help health professionals give more focused support and ensure that influencing factors are addressed so that older people at end‐of‐life receive quality end‐of‐life care.
Experiences of sub‐fertility among Chinese couples in Hong Kong: a qualitative study
Authors: Loke Alice Y , Yu Pui‐Ling , Hayter Mark
Published: April 2011

Aim.  This study aimed to explore the lived experience of sub‐fertility among Chinese couples in Hong Kong.

Background.  In Chinese culture, the duty of young married couples is to bear children to carry on the family line. Married couples who are unable to bear children often experience personal psychological stress and social pressure.

Design.  Qualitative, exploratory study.

Methods.  Seven women and four men in Hong Kong were interviewed to explore their lived experiences of being involuntarily childless. Collaizi’s phenomenological methods guided data collection and analysis.

Results.  Sub‐fertile couples reported feelings of incompleteness, guilt, shame and isolation from the ‘fertile’ world. These couples acknowledged that sub‐fertility had implications on their marital relationship and regretted not having treatment earlier. Some found ways to replace their ‘loss’ and to cope with their situation, and some rationalised by finding reasons that favoured being childless.

Discussion.  It is recommended that family planning should be incorporated into premarital screening and to provide timely support and counselling.

Relevance to clinical practice.  Family planning and fertility should be incorporated into premarital counselling. Sub‐fertile couples should be encouraged to seek medical help, being provided with early referral for investigation and treatment and with support and counselling. Health care professionals should respect the decisions of sub‐fertile couples with regard to investigations or assisted reproductive services. They should also assess how each partner interprets the situation if they encountered difficulty in dealing with the situation.
Nature and quality of antipsychotic prescribing practice in UK psychiatry of intellectual disability services
Authors: Paton C. , Flynn A. , Shingleton‐Smith A. , McIntyre S. , Bhaumik S. , Rasmussen J. , Hardy S. , Barnes T.
Published: April 2011

Background Antipsychotics are perceived to be over‐used in the management of behavioural problems in people with an intellectual disability (ID). Published guidelines have set good practice standards for the use of these drugs for behavioural indications. We sought to identify the range of indications for which antipsychotic drugs are prescribed in people with ID and to audit clinical practice against the standards.

Method Data were collected from the clinical records of individuals with ID who were under the care of mental health services in the UK, and prescribed an antipsychotic drug.

Results The sample comprised 2319 patients from 39 clinical services. Twenty‐seven per cent of the patients had a diagnosis of a psychotic illness (ICD‐10 F20–29) and 27% an affective illness (ICD‐10 F30–39). The proportion who did not have a psychiatric diagnosis ranged from 6% of those with borderline/mild ID to 21% of those with severe/profound ID. Overall, the most common indications for prescribing an antipsychotic drug were comorbid psychotic illness, anxiety and agitation, and a range of behavioural disturbances. The prevalence of use of antipsychotic drugs to manage challenging behaviour in the absence of concomitant mental illness increased with the severity of ID and accounted for almost half of prescriptions in those with severe/profound ID. Adherence to the audit standards related to documentation of clinical indications and review of efficacy was high. Side effect monitoring was less assiduous.

Conclusions In clinical practice, most prescriptions for antipsychotic drugs in people with ID are consistent with the evidence base and the overall quality of prescribing practice, as measured against recognised standards, is good, although in some patients potentially remedial side effects may not be detected and treated.
Activation of cryptic aminoglycoside resistance in Salmonella enterica
Authors: Koskiniemi Sanna , Pränting Maria , Gullberg Erik , Näsvall Joakim , Andersson Dan I
Published: April 2011

Aminoglycoside resistance in bacteria can be acquired by several mechanisms, including drug modification, target alteration, reduced uptake and increased efflux. Here we demonstrate that increased resistance to the aminoglycosides streptomycin and spectinomycin in Salmonella enterica can be conferred by increased expression of an aminoglycoside adenyl transferase encoded by the cryptic, chromosomally located aadA gene. During growth in rich medium the wild‐type strain was susceptible but mutations that impaired electron transport and conferred a small colony variant (SCV) phenotype or growth in glucose/glycerol minimal media resulted in activation of the aadA gene and aminoglycoside resistance. Expression of the aadA gene was positively regulated by the stringent response regulator guanosine penta/tetraphosphate ((p)ppGpp). SCV mutants carrying stop codon mutations in the hemA and ubiA genes showed a streptomycin pseudo‐dependent phenotype, where growth was stimulated by streptomycin. Our data suggest that this phenotype is due to streptomycin‐induced readthrough of the stop codons, a resulting increase in HemA/UbiA levels and improved electron transport and growth. Our results demonstrate that environmental and mutational activation of a cryptic resistance gene can confer clinically significant resistance and that a streptomycin‐pseudo‐dependent phenotype can be generated via a novel mechanism that does not involve the classical rpsL mutations.
A multicenter study on extramammary Paget’s disease in Korea
Authors: Lee Seok‐Jong , Choe Yoon Seok , Jung Hong Dae , Ahn Sung Ku , Cha Young Chang , Cho Kwang Hyun , Choi Hae Young , Chung Kee Yang , Huh Chang Hun , Kim Il Hwan , Kim Ki‐Ho , Kim Moon Bum , Kim Myung Hwa , Kim You Chan , Lee Jee Bum , Lee Mi Woo , Lee Min‐Geol , Lee Weon Ju , Shin Dong Hoon , Shin Jeong‐Hyun , Suh Kee Suck , Won Young Ho ,   (Korean Society for Skin Cancer and Korean Dermatopathology Research Group)
Published: April 2011

Background  There has been little research on extramammary Paget’s disease (EMPD) conducted in Asia.

Methods  The aim of this multicenter study was to investigate the clinicopathological features, biological behavior, and treatment of EMPD in 194 Korean patients over a five‐year period.

Results  As expected, this disease exhibited a male dominance (3.9:1) pattern. To distinguish the true association of malignancy with EMPD from coincidental occurrence of malignancy, we modified Chanda’s guidelines. This analysis determined that there was an accompanying malignancy in 26 patients (14.4%), which included stomach (six cases), rectum (three cases), and colon (three cases) malignancies. With regard to treatment, 112 patients (58%) underwent conventional excisions, and 22 (11.4%) had Mohs surgery. Follow‐up data for periods of 3–180 months were available for 147 patients; these data indicated that 42 patients (28.6%) experienced local recurrences. Patients who underwent Mohs micrographic surgery experienced a lower rate of recurrence (12.5%) than patients who underwent conventional excision (33.3%).

Conclusions  In summary, this Korean population‐based study demonstrated that the clinical features of EMPD, such as gender predominance, are consistent with reports from other Asian population‐based studies. However, this study additionally demonstrated that the rate of association with malignancy in the Korean population (14.4%) was higher than that observed in other Asian studies.
Cowden’s syndrome: a clinical, immunological, and histopathological study
Authors: Amer Mohamed , Mostafa Fawzia Farag , Attwa Enayat Mohamed , Ibrahim Samia
Published: April 2011

Background  Cowden’s syndrome is a rare, autosomal dominant condition characterized by hamartomas of the gastrointestinal tract and cancer of the breast and thyroid. This study describes the clinical, immunological, and histopathological status of four Cowden’s syndrome cases from two different families.

Methods  Biopsies were taken from different skin, mucous membrane, and intestinal lesions in all patients. Blood samples from patients and their parents were also examined.

Results  Two brothers in the first family had more flexural distribution of papular and warty skin lesions as well as other manifestations of the syndrome, including recurrent pyogenic and fungal infections. Flow cytometric study revealed decreased total T and B‐cell percentages and abnormal helper : suppressor ratios in these patients. The other two patients from the second family showed the classical picture of the syndrome and normal immunological parameters. Histopathologically, most skin lesions of the face showed trichilemmomas, and all oral and some of the other skin lesions showed benign fibromas with giant cells (Cowden’s fibroma). Examination of intestinal biopsies revealed hamartomatous and hyperplastic polyps.

Conclusions  Some cases of Cowden’s syndrome may be associated with prominent flexural skin lesions, recurrent pyogenic and fungal skin infections, decreased total T and B‐cell counts, and an abnormal helper : suppressor ratio.
Cutaneous lepidopterism: dermatitis from contact with moths of Hylesia metabus (Cramer 1775) (Lepidoptera: Saturniidae), the causative agent of caripito itch
Authors: Paniz‐Mondolfi Alberto E. , Pérez‐Alvarez Alexandra M. , Lundberg Ulf , Fornés Lizette , Reyes‐Jaimes Oscar , Hernández‐Pérez Marier , Hossler Eric
Published: April 2011

Background  Lepidopterism derived from contact with arthropods and/or their products can result in adverse reactions that vary in severity from mild irritation to severe reactions including anaphylactic shock and death. Lepidopterism includes cutaneous and/or mucosal manifestations, systemic symptoms, or both mucocutaneous and systemic manifestations.

Objective  Epidemic outbreaks of dermatitis due to Hylesia sp. have been recorded in several countries of Latin America. The impact of climatic changes occurring presently on migrational and reproductive cycles of Hylesia metabus is also discussed in this study.

Materials and methods  In Venezuela, swarms of migrating H. metabus moths are historically recognized as the causative agents of “Caripito itch,” a disease that has become an important public health problem.

Results:  In this review, we present a series of four case reports reflecting the wide clinical pleomorphism exhibited in lepidopterism by H. metabus.

Conclusion  Although dermatitis caused by these moths is usually resistant to all therapeutic treatment, individualization of therapy based on symptoms led to successful treatment in all four cases.