bluuebunny/crossref_metadata_2025 huggingface dataset:
Microcrystalline silicon solar cells with an open-circuit voltage above 600mV
Authors: van den Donker M. N. , Klein S. , Rech B. , Finger F. , Kessels W. M. M. , van de Sanden M. C. M.
Published: April 2007

Microcrystalline silicon solar cells with an open-circuit voltage surpassing the 600mV barrier were prepared by combining the use of a hot wire deposited p-i interface with that of an i layer deposited by radio-frequency parallel plate plasma deposition using controlled SiH4 flow profiling. The control of the bulk and interface properties facilitated effective charge carrier collection from i layers with a crystalline volume fraction as low as ∼30%. Judging from the absorption in the infrared and the excellent charge carrier transport, the optoelectronic properties of this material were still dominated by the crystalline rather than the amorphous phase.
Effects of gate edge profile on off-state leakage suppresion in metal gate/high-k dielectric n-type metal-oxide-semiconductor field effect transistors
Authors: Kang Chang Yong , Choi Rino , Song S. C. , Lee B. H.
Published: April 2007

The impact of process integration on device characteristics of metal gate/high-k device was investigated systematically. It was found that the profile of gate stack edge and following processes should be optimized to achieve low gate-induced drain leakage, gate leakage, and high drive current. For low standby power applications, an offset of high-k dielectric layer was more desirable. With an optimized gate edge profile, the authors achieved 100 times lower off-state current compared to previous reported results. However, the saturation current degradation was minimal.
Photoluminescence of individual doped GaAs∕AlGaAs nanofabricated quantum dots
Authors: Kalliakos Sokratis , García César Pascual , Pellegrini Vittorio , Zamfirescu Marian , Cavigli Lucia , Gurioli Massimo , Vinattieri Anna , Pinczuk Aron , Dennis Brian S. , Pfeiffer Loren N. , West Ken W.
Published: April 2007

Dilute arrays of GaAs∕AlGaAs modulation-doped quantum dots with same sizes fabricated by electron beam lithography and low impact reactive ion etching exhibit highly uniform luminescence lines. Single quantum dots display spectral emission with peak energies and linewidths linked largely to the geometrical diameter of the dot and to the built-in electron population. Multicharged excitonic and biexcitonic emission intensities have activation energy of about 2meV. These results highlight the potential of high quality nanofabricated quantum dots for applications in areas that require fine control of optical emission.
Role of the internal strain on the incomplete Si∕SiO2 phase separation in substoichiometric silicon oxide films
Authors: La Magna A. , Nicotra G. , Bongiorno C. , Spinella C. , Grimaldi M. G. , Rimini E. , Caristia L. , Coffa S.
Published: April 2007

Silicon nanoclusters were formed in plasma-enhanced chemical vapor deposited substoichiometric silicon oxide films by annealing at 1100°C for 1∕2h as a function of different deposition parameters. The samples were analyzed by energy filtered transmission electron microscopy and Rutherford backscattering. At any deposition condition, the clustered silicon concentration is significantly lower than the initial silicon excess concentration. This behavior is explained by taking into account the free energy difference between the metastable SiO and stable SiO2 phase and the strain energy associated with the different atomic densities of Si and SiO2.
Three-dimensional photonic crystal by holographic contact lithography using a single diffraction mask
Authors: Zhou Guangya , Chau Fook Siong
Published: April 2007

The authors present an approach for fabrication of three-dimensional (3D) periodic micro-nanoscale structures through holographic contact lithography using a single diffraction mask. The mask functions to split an incoming laser beam into four diffracted beams in an umbrella configuration to produce a 3D periodic interference pattern immediately behind it. The recording photoresist can thus be placed in direct contact with or in close proximity to the mask. The proposed approach was investigated using 3D finite-difference time-domain method. Simulation results confirmed the feasibility of the method.
Role of surface plasmon in second harmonic generation from gold nanorods
Authors: Hubert C. , Billot L. , Adam P.-M. , Bachelot R. , Royer P. , Grand J. , Gindre D. , Dorkenoo K. D. , Fort A.
Published: April 2007

The role of surface plasmon in second harmonic generation from arrays of gold nanorod particles excited by femtosecond laser pulses is investigated as a function of incident light polarization and irradiation wavelength. In addition to photoluminescence, a peak of second harmonic is observed and is found to depend on the polarization and wavelength of the fundamental frequency laser beam. In particular, the authors found similarities between extinction spectra of the nanoparticles and spectra of emmitted second harmonic. This behavior can be explained by resonant excitation of localized surface plasmon resonances.
Stress-induced width-dependent degradation of low-temperature polycrystalline silicon thin-film transistor
Authors: Hsieh Szu-I , Liang Hsing-Yi , Lin Chrong-Jung , King Ya-Chin , Chen Hung-Tse
Published: April 2007

This study characterizes the stress-induced subthreshold degradation effect in low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) formed using sequential lateral solidified (SLS) crystallization on a glass substrate. The SLS process is adopted to improve carrier mobility by increasing the grain size. The deterioration of the innate subgrain boundaries that are induced by channel hot-electron stress causes these transistors to exhibit double-hump subthreshold characteristics which become more prominent as the width of the channel increases. A physical theory and a proposed transistor network model accurately explain and predict the width-dependent subthreshold degradation characteristics of these stress LTPS-TFTs.
Power-law transient charge transport in a nonpolar liquid
Authors: Beunis F. , Strubbe F. , Neyts K. , Verschueren A. R. M.
Published: April 2007

Transient current measurements in response to a voltage step can reveal a lot of information about the nature, the origin, and the properties of electrically charged species in nonpolar media. In situations where the influence of the charges on the electric field can be neglected, interpretation is straightforward. However, this condition is not fulfilled in many applications. This work provides an approximate analytical description, illustrated by measurements and simulations, for cases in which the contribution of the charge density to the electric field is comparable in magnitude to the contribution of the applied voltage.
Application of the Nelson model to four timelag fuel classes using Oklahoma field observations: model evaluation and comparison with National Fire Danger Rating System algorithms
Authors: Carlson J. D. , Bradshaw Larry S. , Nelson Ralph M. , Bensch Randall R. , Jabrzemski Rafal
Published: April 2007

The application of a next-generation dead-fuel moisture model, the ‘Nelson model’, to four timelag fuel classes using an extensive 21-month dataset of dead-fuel moisture observations is described. Developed by Ralph Nelson in the 1990s, the Nelson model is a dead-fuel moisture model designed to take advantage of frequent automated weather observations. Originally developed for 10-h fuels, the model is adaptable to other fuel size classes through modification of the model’s fuel stick parameters. The algorithms for dead-fuel moisture in the National Fire Danger Rating System (NFDRS), on the other hand, were originally developed in the 1970s, utilise once-a-day weather information, and were designed to estimate dead-fuel moisture for mid-afternoon conditions. Including all field observations over the 21-month period, the Nelson model showed improvement over NFDRS for each size fuel size class, with r2 values ranging from 0.51 (1000-h fuels) to 0.79 (10-h fuels). However, for observed fuel moisture at or below 30%, the NFDRS performed better than the Nelson model for 1-h fuels and was about the same accuracy as the Nelson for 10-h fuels. The Nelson model is targeted for inclusion in the next-generation NFDRS.
Biological screening of natural products and drug innovation in China
Authors: Wang Ming-Wei , Hao Xiaojiang , Chen Kaixian
Published: April 2007

Natural products have been applied to human healthcare for thousands of years. Drug discovery in ancient times was largely by chance and based on clinical practices. As understanding of therapeutic benefits deepens and demands for natural products increase, previously serendipitous discoveries evolve into active searches for new medicines. Many drugs presently prescribed by physicians are either directly isolated from plants or are artificially modified versions of natural products. Scientists are looking for lead compounds with specific structures and pharmacological effects often from natural sources. Experiences and successes of Chinese scientists in this specialized area have resulted in a number of widely used drugs. The tremendous progress made in life sciences has not only revealed many pathological processes of diseases, but also led to the establishment of various molecular and cellular bioassays in conjunction with high-throughput technologies. This is advantageous and permits certain natural compounds that are difficult to isolate and purify, and compounds that are difficult to synthesize, to be assayed. The transition from traditional to empirical and to molecular screening will certainly increase the probability of discovering new leads and drug candidates from natural products.
Mutations within the FGF5 gene are associated with hair length in cats
Authors: Drögemüller C. , Rüfenacht S. , Wichert B. , Leeb T.
Published: April 2007

Hereditary hair length variability in mice and dogs is caused by mutations within the fibroblast growth factor 5 (FGF5) gene. The aim of this study was to evaluate the feline FGF5 orthologue as a functional candidate gene for the long hair phenotype in cats, which is recessive to short hair. We amplified the feline FGF5 cDNA and characterised two alternatively spliced transcripts by RT‐PCR. Comparative cDNA and genomic DNA sequencing of long‐ and short‐haired cats revealed four non‐synonymous polymorphisms in the FGF5 coding sequence. A missense mutation (AM412646:c.194C>A) was found in the homozygous state in 25 long‐haired Somali, Persian, Maine Coon, Ragdoll and crossbred cats. Fifty‐five short‐haired cats had zero or one copy of this allele. Additionally, we found perfect co‐segregation of the c.194C>A mutation within two independent pedigrees segregating for hair length. A second FGF5 exon 1 missense mutation (AM412646:c.182T>A) was found exclusively in long‐haired Norwegian Forest cats. The c.182T>A mutation probably represents a second FGF5 mutation responsible for long hair in cats. In addition to the c.194C>A mutation, a frameshift mutation (AM412646:c.474delT) was found with a high frequency in the long‐haired Maine Coon breed. Finally, a missense mutation (AM412646:c.475A>C) was also associated with the long‐haired phenotype in some breeds. However, as one short‐haired cat was homozygous for this polymorphism, it is unlikely that it has a functional role in the determination of hair length.
Single nucleotide polymorphisms for pig identification and parentage exclusion
Authors: Rohrer G. A. , Freking B. A. , Nonneman D.
Published: April 2007

Single nucleotide polymorphisms (SNPs) have become an important type of marker for commercial diagnostic and parentage genotyping applications as automated genotyping systems have been developed that yield accurate genotypes. Unfortunately, allele frequencies for public SNP markers in commercial pig populations have not been available. To fulfil this need, SNP markers previously mapped in the USMARC swine reference population were tested in a panel of 155 boars that were representative of US purebred Duroc, Hampshire, Landrace and Yorkshire populations. Multiplex assay groups of 5–7 SNP assays/group were designed and genotypes were determined using Sequenom's massarray® system. Of 80 SNPs that were evaluated, 60 SNPs with minor allele frequencies >0.15 were selected for the final panel of markers. Overall identity power across breeds was 4.6 × 10−23, but within‐breed values ranged from 4.3 × 10−14 (Hampshire) to 2.6 × 10−22 (Yorkshire). Parentage exclusion probability with only one sampled parent was 0.9974 (all data) and ranged from 0.9594 (Hampshire) to 0.9963 (Yorkshire) within breeds. Sire exclusion probability when the dam's genotype was known was 0.99998 (all data) and ranged from 0.99868 (Hampshire) to 0.99997 (Yorkshire) within breeds. Power of exclusion was compared between the 60 SNP and 10 microsatellite markers. The parental exclusion probabilities for SNP and microsatellite marker panels were similar, but the SNP panel was much more sensitive for individual identification. This panel of SNP markers is theoretically sufficient for individual identification of any pig in the world and is publicly available.
Successful treatment of thrombotic microangiopathy after haematopoietic stem cell transplantation with rituximab
Authors: Au Wing‐Yan , Ma Edmond S. , Lee Tsz‐Leung , Ha Shau‐Yin , Fung Alvin T. , Lie Albert K. W. , Kwong Yok‐Lam
Published: April 2007

Thrombotic microangiopathy (TMA) is a grave complication after haematopoietic stem cell transplantation (HSCT) and effective treatment is undefined. Five patients with postHSCT TMA, which was refractory to at least 1 week of plasma exchange and prednisolone, were treated with rituximab (375 mg/m2/week × 4). Remission was achieved in four patients, of whom three remained in remission and one had died of sepsis at a median follow‐up of 10 months. ADAMTS13 levels were low in all evaluable patients, and only one patient showed significant anti‐ADAMTS13 antibody. The levels of ADAMTS13 and anti‐ADAMTS13 antibody did not change significantly with rituximab‐induced remission.
Absolute lymphocyte count predicts therapeutic efficacy of rituximab therapy in follicular lymphomas
Authors: Behl Deepti , Ristow Kay , Markovic Svetomir N. , Witzig Thomas E. , Habermann Thomas M. , Colgan Joseph P. , Inwards David J. , White William L. , Ansell Stephen M. , Micallef Ivana N. , Johnston Patrick B. , Porrata Luis F.
Published: April 2007

The immunologic mechanisms of action of rituximab include complement mediated lysis and antibody‐dependent cellular cytotoxicity. We hypothesised that a stronger host immune system prior to rituximab therapy for follicular (grades 1and 2) lymphomas (FL) would result in better response rates and longer time to progression (TTP). Thus, we studied the role of absolute lymphocyte count (ALC) prior to rituximab therapy on treatment efficacy and TTP in FL patients. Between 1996 and 2002, 79 FL patients were treated with single agent rituximab during their lymphoma treatment at the Mayo Clinic. The median age of the cohort was 56·6 years (range: 25–98 years). The median TTP was 12·5 months (range: 1–76 months). Superior TTP was observed with an ALC ≥0·89 × 109/l (n = 40) compared with an ALC <0·89 × 109/l (n = 39) at the time of rituximab therapy (median: 36·5 vs. 8·1 months, respectively,P < 0·0009). Higher complete response rates were observed in the ALC ≥0·89 × 109/l (23/40, 58%) compared with the ALC <0·89 × 109/l (5/39, 13%) (P < 0·0001). Multivariate analysis showed ALC to be an independent predictor for TTP. This study supports our hypothesis that a higher ALC predicts longer TTP following rituximab therapy.
A new least‐squares minimization approach to depth and shape determination from magnetic data
Authors: Abdelrahman El‐Sayed M. , Abo‐Ezz Eid. R. , Essa Khalid S. , El‐Araby T.M. , Soliman Khaled S.
Published: April 2007

We have developed a least‐squares minimization approach to depth determination using numerical second horizontal derivative anomalies obtained from magnetic data with filters of successive window lengths (graticule spacings). The problem of depth determination from second‐derivative magnetic anomalies has been transformed into finding a solution to a non‐linear equation of the form, f(z) = 0. Formulae have been derived for a sphere, a horizontal cylinder, a dike and a geological contact. Procedures are also formulated to estimate the magnetic angle and the amplitude coefficient.

We have also developed a simple method to define simultaneously the shape (shape factor) and the depth of a buried structure from magnetic data. The method is based on computing the variance of depths determined from all second‐derivative anomaly profiles using the above method. The variance is considered a criterion for determining the correct shape and depth of the buried structure. When the correct shape factor is used, the variance of depths is less than the variances computed using incorrect shape factors.

The method is applied to synthetic data with and without random errors, complicated regionals, and interference from neighbouring magnetic rocks. Finally, the method is tested on a field example from India. In all the cases examined, the depth and the shape parameters are found to be in good agreement with the actual parameters.
Localized cultural denoising of high‐resolution aeromagnetic data
Authors: Paoletti V. , Fedi M. , Florio G. , Rapolla A.
Published: April 2007

We show how a denoising technique based on the wavelet transform can be used to deal with localized noise related to DC electrified railway lines. This method, which performs localized and sharp filtering of cultural noise, was applied to high‐resolution aeromagnetic data acquired in the Phlegrean volcanic area, southern Italy, in 1999 and 2001. The helicopter‐borne survey was aimed at giving new detailed insights into the distribution of the magnetization of the area and, therefore, into the volcanological characteristics of the region. The surveyed area is characterized by the presence of towns, buildings and DC electrified railway lines whose magnetic effects influenced the measurements and were responsible for some of the measured anomalies. This cultural noise has, therefore, to be minimized as much as possible in order to allow the data to be interpreted accurately. Due to the excellent space‐scale localization properties of the discrete wavelet transform, the cultural disturbance was removed very precisely, leaving the field in the adjacent areas unchanged.
Granulocyte–macrophage colony‐stimulating factor drives monocytes to CD14low CD83+ DCSIGN– interleukin‐10‐producing myeloid cells with differential effects on T‐cell subsets
Authors: Ganguly Dipyaman , Paul Kausik , Bagchi Jayashree , Rakshit Srabanti , Mandal Labanya , Bandyopadhyay Gautam , Bandyopadhyay Santu
Published: April 2007

Summary Granulocyte–macrophage colony‐stimulating factor (GM‐CSF) has long been found to have growth‐promoting effects on multipotent haematopoietic lineages, specifically granulocytes and macrophages. GM‐CSF combined with interleukin‐4 (IL‐4) drives monocytes to become myeloid dendritic cells (mDCs) in vitro. We report that culturing human monocytes with GM‐CSF alone generates myeloid cells (GM‐Mono) that have lower expression of CD14 than monocytes and that fail to express DC‐SIGN. GM‐Monos, however, express CD83 and the transcription factor PU.1, although at a lower level than the conventional mDCs generated in the presence of GM‐CSF and IL‐4. On stimulation with tumour necrosis factor‐α, interferon‐γ and anti‐CD40 monoclonal antibody, the GM‐Monos predominantly produced IL‐10 but were less efficient in IL‐12 production. In a primary allogeneic mixed lymphocyte reaction, GM‐Monos induced hyporesponsiveness and IL‐10‐biased cytokine production in CD4+ T cells. In fresh mixed lymphocyte reaction, GM‐Monos inhibited conventional mDC‐induced allogeneic CD4+ T‐cell proliferation. GM‐Mono‐induced inhibition of allogeneic CD4+ T‐cell proliferation was partially attributed to IL‐10. Interestingly, GM‐Monos neither induced hyporesponsiveness in allogeneic CD8+ T cells nor inhibited conventional mDC‐induced allogeneic CD8+ T‐cell proliferation. Taken together, we characterize monocyte‐derived CD14low CD83+ cells generated by GM‐CSF that can induce tolerance or stimulation of T cells depending on T‐cell subsets.
Increased levels of interferon‐γ primed by culture filtrate proteins antigen and CpG‐ODN immunization do not confer significant protection against Mycobacterium tuberculosis infection
Authors: Morais da Fonseca Denise , Lopes Silva Célio , Oliveira e Paula Marina , Garcia Soares Edson , Marchal Gilles , Horn Cynthia , Deperon Bonato Vânia Luiza
Published: April 2007

The results of various animal model studies of tuberculosis (TB) suggest that culture filtrate proteins (CFPs), which are antigens secreted by Mycobacterium tuberculosis, are largely responsible for improvements in TB vaccines. The great obstacle to developing protein subunit vaccines is that adjuvants are required in order to stimulate relevant protective immune responses. Acting as immune adjuvants, CpG‐oligodeoxynucleotides (CpG‐ODNs) promote the activation of Th1 cells and of pro‐inflammatory cytokines. To evaluate the adjuvant role of CpG‐ODNs in conferring enhanced immunogenic capacity and protection against M. tuberculosis, we immunized mice with CFP antigen combined with synthetic CpG‐ODNs (CFP/CpG) or with incomplete Freund's adjuvant (IFA) (CFP/IFA). Immunization with CFP/CpG induced a T helper 1 (Th1)‐biased response accompanied by a higher immunoglobulin G2a (IgG2a) antibody/IgG1 antibody ratio, elevated production of interferon‐γ (IFN‐γ) by spleen cells and in lungs. However, CFP/IFA‐immunized mice presented higher levels of IgG1 antibodies, as well as increased production of IFN‐γ, interleukin (IL)‐5, and IL‐10 by spleen cells, together with lower levels of IFN‐γ in the lungs. Despite the stronger Th1 response seen in both groups, believed to be necessary for protection against TB, only mice immunized with CFP/IFA were protected after M. tuberculosis infection. Lung histology revealed that lung parenchyma were better preserved in CFP/IFA‐immunized mice, which also presented intense lymphocyte recruitment to the lesion, whereas CFP/CpG‐immunized mice presented severe pulmonary injury accompanied by necrosis. Based on the data presented, we discuss the widely accepted paradigm that high levels of IFN‐γ are directly correlated with protection against experimental TB.
Is a new paradigm emerging for oceanic island biogeography?
Authors: Heaney Lawrence R.
Published: April 2007

Following several decades during which two dissimilar and incompatible models (equilibrium and vicariance) dominated island biogeography, recent publications have documented patterns that point the way towards a new paradigm that includes elements of both models, as well as some novel aspects. Many of these seminal contributions have been made possible by the recent development of robust, temporally calibrated phylogenies used in concert with increasingly precise and reliable geological reconstructions of oceanic regions. Although a new general model of oceanic island biogeography has not yet been proposed, in this brief overview I present six hypotheses that summarize aspects of the emerging paradigm. These hypotheses deal with: the frequency of dispersal over oceanic water barriers by terrestrial organisms; the existence of substantial variation in the amount of dispersal (and gene flow) within a given set of related species within a given archipelago; the frequency, extent and impact on species richness of diversification within archipelagos; the frequent correlation of island age and the age of the species that live on the island; the long‐term persistence of species on oceanic islands; and the occasional recolonization of continents by species from clades that diversified on islands. Identifying, testing, and seeking means of synthesizing these and other emerging hypotheses may allow a new conceptual paradigm to emerge.
Phase transitions of silver and silver–palladium alloys immersed in mercury
Authors: CHERN LIN J. H. , YUAN J. Y. , HO W. F. , JU C. P.
Published: April 2007

summary  A series of Ag–Hg and Ag–Pd–Hg phases have been prepared by immersion in mercury and subsequent heat treatment of pure Ag and a series of Ag–Pd alloys. Phase transitions, along with the changes involved in morphology and chemistry, are investigated. Experimental results indicate that when mercury‐immersed Ag discs are heat‐treated at 90 °C for 12 h, large (>50 μm) crystals with Ag/Hg atomic ratios close to those of stoichiometric AgHg2 form on the Ag surface. Heat treatment for 36 h causes these crystals to disintegrate into smaller (majority <10 μm) Ag2Hg3 (γ1) crystals. After 60 h, the stoichiometric γ1 crystals further breakdown into even smaller stoichiometric AgHg(β1) crystals. The oft‐referenced β1 phase Ag1·1Hg0·9 is not supported in the present study. Addition of Pd to Ag has a dramatic effect on the morphology of the γ1 phase. With more addition of Pd, large‐faceted and elongated γ1 crystals tend to grow in the midst of smaller matrix γ1 crystals. All three different Pd‐containing crystals have (Ag + Pd)/Hg ratios very close to those of the stoichiometric γ1 phase, indicating that added Pd tends to replace Ag, rather than Hg, in the γ1 phase.
Characteristics of a jaw reflex in humans with temporomandibular disorders: a preliminary report
Authors: MAILLOU P. , CADDEN S. W.
Published: April 2007

summary  Electromyography was used to compare characteristics of an inhibitory jaw reflex in 10 temporomandibular disorder patients and 10 age‐ and sex‐matched healthy controls. The methodology was novel in that the reflex was that evoked in the active masseter muscle, by electrical stimulation of perioral skin. This response has advantages over those previously studied as it avoids problems associated with stimulating in the moist intra‐oral environment and it is monophasic, thus permitting easy quantification. The results have shown that (i) with the stimulation parameters employed, the reflex was present in all 10 control subjects, but in only eight of 10 temporomandibular disorder patients. (ii) When stimulation intensities were expressed as multiples of sensory threshold, there was no significant difference in the minimum level of stimulation required to evoke the reflex between the groups, although there was a trend for the patients with temporomandibular disorders to require higher intensities. (iii) Comparison of data from subjects giving responses at the same stimulus intensity (6 × sensory threshold: seven temporomandibular disorder patients, eight controls), showed no significant differences in the latencies or magnitudes of the reflex between the groups. However, the overall duration of the reflex was significantly shorter for the patients with temporomandibular disorders, with the reflex finishing significantly earlier. Thus even within the limitations of this study, it appears that an inhibitory jaw reflex evoked from stimulation around the mouth, may be weaker in temporomandibular disorder patients. This conclusion is consistent with previous studies on more complex jaw reflexes evoked by intra‐oral stimuli.
The prevalence of tooth discolouration and the self‐satisfaction with tooth colour in a Chinese urban population
Authors: XIAO J. , ZHOU X. D. , ZHU W. C. , ZHANG B. , LI J. Y. , XU X.
Published: April 2007

Summary  Objectives: To determine the prevalence of tooth discolouration, self‐satisfaction with tooth colour, and correlation with socio‐demographic‐behavioural factors in adults and teenagers in Chengdu, China. Design: A cross‐sectional survey.

Participants: 405 Chinese urban adults and teenagers from a multistage random probability sample. Methods: Tooth colour was measured on the maxillary central incisors using a colorimeter. Tooth discolouration was determined according to the discolouration level figure and evaluation criteria. Self‐satisfaction with tooth colour was assessed on a five‐point qualitative scale. Data were coded and analyzed using SPSS software. Results: The mean values for L*, a* and b* were 70·67 (s.d. 1·91), 4·29 (s.d. 2·05) and 17·51 (s.d. 4·13), respectively. Age and sex were the most important factors associated with tooth colour (P < 0·05). About half of the study population (48·9%) suffered from some tooth discolouration, and 52·6% were dissatisfied with their tooth colour. Education and smoking were significant factors affecting self‐satisfaction with tooth colour (P < 0·05). Conclusions: Tooth discolouration is common among the Chinese, and many Chinese are dissatisfied with their tooth colour. Self‐satisfaction with tooth colour decreased with increasing severity of discolouration. Further research is needed to determine types of tooth discolouration among broader regions in China.
Contemporary pollen and seed dispersal in a Prunus mahaleb population: patterns in distance and direction
Authors: GARCÍA C. , JORDANO P. , GODOY J. A.
Published: April 2007

Pollination and seed dispersal determine the spatial pattern of gene flow in plant populations and, for those species relying on pollinators and frugivores as dispersal vectors, animal activity plays a key role in determining this spatial pattern. For these plant species, reported dispersal patterns are dominated by short‐distance movements with a significant amount of immigration. However, the contribution of seed and pollen to the overall contemporary gene immigration is still poorly documented for most plant populations. In this study we investigated pollination and seed dispersal at two spatial scales in a local population of Prunus mahaleb (L.), a species pollinated by insects and dispersed by frugivorous vertebrates. First, we dissected the relative contribution of pollen and seed dispersal to gene immigration from other parts of the metapopulation. We found high levels of gene immigration (18.50%), due to frequent long distance seed dispersal events. Second, we assessed the distance and directionality for pollen and seed dispersal events within the local population. Pollen and seed movement patterns were non‐random, with skewed distance distributions: pollen tended moved up to 548 m along an axis approaching the N–S direction, and seeds were dispersed up to 990 m, frequently along the SW and SE axes. Animal‐mediated dispersal contributed significantly towards gene immigration into the local population and had a markedly nonrandom pattern within the local population. Our data suggest that animals can impose distinct spatial signatures in contemporary gene flow, with the potential to induce significant genetic structure at a local level.
VZ CVn: a close binary system with γ Doradus-like variations
Authors: İbanoǧlu C. , Taş G. , Sipahi E. , Evren S.
Published: April 2007

We present new photometric two-colour observations of the double-lined close binary star VZ CVn. Combining two data sets obtained in 1971–72 and in 2006, the physical parameters of both components were derived. After removing the light variations due to the eclipses and proximity effects, a periodic variation in the more massive component with a dominant period of 1.068 76 d could be detected in the first photometric data set. In accordance with its position on the Hertzsprung–Russell diagram and both its pulsation period and pulsation constant of 0.62 d, the primary component of VZ CVn should be an excellent γ Doradus candidate. The less massive secondary component seems to have smaller radius with respect to its mass. Both components appear to have lower luminosities with respect to their masses; hence, their radiative properties seem to be different. The evolutionary status of the components is also discussed.
The ABC transporter AtPDR8 is a cadmium extrusion pump conferring heavy metal resistance
Authors: Kim Do‐Young , Bovet Lucien , Maeshima Masayoshi , Martinoia Enrico , Lee Youngsook
Published: April 2007

Cadmium (Cd) and lead (Pb) are widespread pollutants that are toxic to plant growth. The expression of AtPDR8 was upregulated in cadmium‐ or lead‐treated Arabidopsis thaliana. To test whether AtPDR8 is involved in heavy metal resistance, we examined transgenic Arabidopsis that over‐expressed AtPDR8 and RNAi plants that exhibited a severely reduced AtPDR8 transcript level, as well as T‐DNA insertion mutants of this ABC transporter. AtPDR8‐over‐expressing plants were more resistant to Cd2+ or Pb2+ than the wild‐type and had lower Cd contents. In contrast, AtPDR8 RNAi transgenic plants and T‐DNA insertion lines were more sensitive to Cd2+ or Pb2+ compared to wild‐type plants and had higher Cd contents. The GFP–AtPDR8 protein was targeted to the plasma membrane, and GUS activity was present in most cells but strongest in the root hair and epidermal cells. Cd extrusion was higher in the AtPDR8‐over‐expressing plants in a flux assay using isolated protoplasts and radioactive 109Cd, and was lower in the RNAi transgenic plants than in the wild‐type. Together, these data strongly support a role for AtPDR8 as an efflux pump of Cd2+ or Cd conjugates at the plasma membrane of Arabidopsis cells. As AtPDR8 has been suggested to be involved in the pathogen response and in the transport of chemicals that mediate pathogen resistance, this ABC protein is likely to transport a very broad range of substrates.
Infection of tobacco with different Pseudomonas syringae pathovars leads to distinct morphotypes of programmed cell death
Authors: Krzymowska Magdalena , Konopka‐Postupolska Dorota , Sobczak Miroslaw , Macioszek Violetta , Ellis Brian E. , Hennig Jacek
Published: April 2007

Tobacco plants (Nicotiana tabacum cv. Xanthi‐nc) infiltrated with either of two pathovars of Pseudomonas syringae– an avirulent strain of P. syringae pv. tabaci (Pst) or the non‐host pathogen P. syringae pv. maculicola M2 (Psm) – developed a hypersensitive response (HR). There were considerable differences in HR phenotype, timing and sequence of cell dismantling between the two pathosystems. Following Psm infiltration, the first macroscopic signs were visible at 4.5 h post‐infiltration (hpi). Simultaneously, increased plasma membrane permeability was observed, suggesting that the loss of cell membrane integrity initiates the macroscopic HR evoked by Psm. In contrast, after Pst treatment there was a distinct time lapse between the first signs of tissue collapse (9 hpi) and the occurrence of plasma membrane discontinuity (12 hpi). Ultrastructural studies of cells undergoing the HR triggered by Psm and Pst revealed distinct patterns of alterations in morphology of organelles. Moreover, while different forms of nuclear degeneration were observed in leaf zones infiltrated with Pst, we failed to detect any abnormalities in the nuclei of Psm‐treated tissue. In addition, application of synthetic caspase inhibitors (Ac‐DEVD‐CHO, Ac‐YVAD‐CMK) abolished HR induced by Pst, but not Psm. Our observations suggest that different cell death mechanisms are executed in response to Psm and Pst. Interestingly, pre‐inoculation with Pst, but not with Psm, induced a long‐distance acquired resistance (LDAR) response, even though locally a typical set of defense responses, including acquired resistance, was activated locally in response to Psm. The failure of Psm to induce LDAR may be due to the rapid degeneration of bundle sheath cells resulting from Psm infection.
A mutation in NLA, which encodes a RING‐type ubiquitin ligase, disrupts the adaptability of Arabidopsis to nitrogen limitation
Authors: Peng Mingsheng , Hannam Carol , Gu Honglan , Bi Yong‐Mei , Rothstein Steven J.
Published: April 2007

Abundant nitrogen is required for the optimal growth and development of plants, while numerous biotic and abiotic factors that consume soil nitrogen frequently create a nitrogen limitation growth condition. To cope with this, plants have evolved a suite of adaptive responses to nitrogen limitation. However, the molecular mechanism governing the adaptability of plants to nitrogen limitation is totally unknown because no reported mutant defines this trait. Here we isolated an Arabidopsis mutant, nla (nitrogen limitation adaptation), and identified the NLA gene as an essential component in this molecular mechanism. Supplied with insufficient inorganic nitrogen (nitrate or ammonium), the nla mutant failed to develop the essential adaptive responses to nitrogen limitation, but senesced much earlier and more rapidly than did the wild type. Under other stress conditions including low phosphorus nutrient, drought and high temperature, the nla mutant did not show this early senescence phenotype, but closely resembled the wild type in growth and development. Map‐based cloning of NLA revealed that this gene encodes a RING‐type ubiquitin ligase, and nla is a deletion mutation which does not code for the RING domain in the NLA protein. The NLA protein is localized to the nuclear speckles, where this protein interacts with the Arabidopsis ubiquitin conjugase 8 (AtUBC8). In the nla mutant, the deletion of the RING domain from NLA altered its subcellular localization, disrupted the interaction between NLA and AtUBC8 and caused the early senescence phenotype induced by low inorganic nitrogen. All the results indicate that NLA is a positive regulator for the development of the adaptability of Arabidopsis to nitrogen limitation.
Invasive zygomycosis in transplant recipients
Authors: Uçkay Ilker , Chalandon Yves , Sartoretti Pascal , Rohner Peter , Berney Thierry , Hadaya Karine , Van Delden Christian
Published: April 2007

Abstract:  Zygomycosis are rare fungal infections occurring mainly in immunocompromised patients. To date only 160 cases have been published in transplant recipients. We report four new cases of zygomycosis in transplant recipients illustrating the large clinical spectrum of this infection: one disseminated infection with heart involvement and one rhinocerebral infection with dissemination in two bone marrow transplant recipients, one cutaneous infection in a liver and one pulmonary infection in a kidney recipient. All cases, except the cutaneous infection that was accessible to surgical resection and a systemic antifungal treatment, were fatal. In transplant recipients cumulating risk factors for zygomycosis, a high index of suspicion is required. Early diagnosis and combining surgery with systemic amphotericin‐B are mandatory to improve survival rates.
The long‐term survival of simultaneous pancreas and kidney transplant with basiliximab induction therapy
Authors: Zhang Rubin , Florman Sandy , Devidoss Sharmila , Zarifian April , Killackey Mary , Paramesh Anil , Fonseca Vivian , Batuman Vecihi , Hamm L. Lee , Slakey Douglas
Published: April 2007

Abstract:  Interleukin‐2 receptor (IL2R) antibody has emerged as an attractive induction therapy for organ transplant. However, the long‐term outcome of basiliximab induction in simultaneous pancreas and kidney (SPK) transplant remains speculative. We retrospectively analyzed the long‐term survivals of 91 consecutive SPK recipients with basiliximab as induction, combination of steroid, tacrolimus (TAC) and mycophenolate acid (MFA) – either mycophenolate mofetil (MMF) or sodium mycophenolate (myfortic) as maintenance. At one, three, five, and seven‐yr, the actual patient survival rate were 91.2%, 90.3%, 88.1%, and 88.2%, respectively; kidney graft survivals were 90.1%, 84.7%, 78.6%, and 70.6%, respectively; and pancreas graft survivals were 86.8%, 80.6%, 71.4%, and 58.8% respectively. There was a low incidence of rejection and CMV infection. Basiliximab induction with TAC, MFA, and steroid maintenance therapy can provide excellent long‐term outcome for SPK recipients.
14th International HLA and Immunogenetics Workshop: Report on the Prospective Chronic Rejection Project
Authors: Ozawa M. , Terasaki P. I. , Lee J. H. , Castro R. , Alberu J. , Alonso C. , Alvarez I. , Toledo R. , Alvez H. , Monterio M. , Teixeira J. , Campbell P. , Ciszek M. , Charron D. , Gautreau C. , Christiansen F. , Conca R. , Gomez B. , Monteon F. , Grosse‐Wilde H. , Heinemann F. , Humar I. , Kamoun M. , Kimball P. , Kobayashi T. , Kupatawintu P. , Leech S. , LeFor W. , Mehra N. , Panigrahi A. , Naumova E. , Norman D. , Piazza A. , Poli F. , Colombo B. , Roy R. , Schonemann C. , Sireci G. , Tanabe K. , Ishida H. , Van den Berg‐Loonen E. , Zeevi A.
Published: April 2007

An international collaborative study of 45 transplant centers was undertaken at the 14th International HLA (human leukocyte antigen) and Immunogenetics Workshop to see if HLA antibodies detected posttransplant are predictive of chronic graft failure. With the newly developed assay, MICA (major histocompatibility complex class I‐related chain A) antibodies were also measured and their effect analyzed. Total of 5219 sera from patients who were more than 6 months posttransplant with functioning graft were tested for HLA antibodies by enzyme‐linked immunosorbent assay, flow cytometry, or Luminex. HLA antibodies were found in 27.2% of kidney patients, 23.6% in the liver, 52.7% in the heart, and 21.7% in the lung. The method of antibody testing did not have a marked influence on the frequency of antibodies detected. MICA antibodies were detected in 15% of kidneypatients, 30% of heart patients, and 31% of liver patients. Among 948 kidney patients who had HLA antibodies, 7.3% had rejected their graft within 1 year of testing, compared with 1.7% in 2615 patients without HLA antibodies (P= 0.8 × 10−17). Death occurred in 1.4% of total kidney patients and did not correlate to the presence of antibodies. We conclude that patients with posttransplant HLA antibodies indeed have a higher rate of chronic graft failure and that posttransplant antibodies are predictive of chronic rejection.
14th International HLA and Immunogenetics Workshop: Report of progress in methodology, data collection, and analyses
Authors: Single R. M. , Meyer D. , Mack S. J. , Lancaster A. , Erlich H. A. , Thomson G.
Published: April 2007

The Biostatistics Component of the 13th International Histocompatibility Workshop (IHWS) developed the PyPop (Python for Population Genomics) software framework for high‐throughput analysis and quality control (QC) assessments of highly polymorphic genotype data. Since its initial release, the software has had several new analysis modules added to it. These additions, combined with improved data filtering and QC modules, facilitate analyses of data at different levels (allele, haplotype, amino acid sequence, and nucleotide sequence). Since the 13th IHWS, much of the human leukocyte antigen (HLA) data from the workshop, QCed via PyPop and other methods, have been made publicly available through the Major Histocompatibility Complex database web site at the National Center for Biotechnology Information (http://ncbi.nih.gov/mhc/). The Anthropology/Human Genetic Diversity component (AHGDC) data have been used in a variety of studies. Prugnolle et al. used this data to corroborate a model of pathogen‐driven selection as a factor related to high levels of diversity at HLA loci. Using a comparative genomics approach contrasting results for HLA and non‐HLA markers, Meyer et al. analyzed a subset of the 13th IHWS AHGDC data and showed that HLA loci show detectable signs of both natural selection and the demographic history of populations.
PyPop update – a software pipeline for large‐scale multilocus population genomics
Authors: Lancaster A. K. , Single R. M. , Solberg O. D , Nelson M. P. , Thomson G.
Published: April 2007

Population genetic statistics from multilocus genotype data inform our understanding of the patterns of genetic variation and their implications for evolutionary studies, generally, and human disease studies in particular. In any given population one can estimate haplotype frequencies, identify deviation from Hardy–Weinberg equilibrium, test for balancing or directional selection, and investigate patterns of linkage disequilibrium. Existing software packages are oriented primarily toward the computation of such statistics on a population‐by‐population basis, not on comparisons among populations and across different statistics. We developed PyPop (Python for Population Genomics) to facilitate the analyses of population genetic statistics across populations and the relationships among different statistics within and across populations. PyPop is an open‐source framework for performing large‐scale population genetic analyses on multilocus genotype data. It computes the statistics described above, among others. PyPop deploys a standard Extensible Markup Language (XML) output format and can integrate the results of multiple analyses on various populations that were performed at different times into a common output format that can be read into a spreadsheet. The XML output format allows PyPop to be embedded as part of a larger analysis pipeline. Originally developed to analyze the highly polymorphic genetic data of the human leukocyte antigen region of the human genome, PyPop has applicability to any kind of multilocus genetic data. It is the primary analysis platform for analyzing data collected for the Anthropological component of the 13th and 14th International Histocompatibility Workshops. PyPop has also been successfully used in studies by our group, with collaborators, and in publications by several independent research teams.
14th International HLA and Immunogenetics Workshop: Report on mapping microsatellite markers in the major histocompatibility complex region
Authors: Gourraud P‐A. , Hoffman D. , Cambon‐Thomsen A. , Feolo M.
Published: April 2007

This paper describes the use of the program e‐pcr to localize 687 known major histocompatability complex (MHC) microsatellite primer pairs to their sequence positions in several genomic assemblies across the MHC region. The sequences used were the Sequences of Sanger Institute’s MHC Haplotype Project: COX, PGF, QBL, as well as the Celera, and Reference (PGF across extended MHC) sequences from the NCBI genomic build 36. More than 95% (664/687) of the markers mapped unambiguously to the Reference assembly sequence. All primer pairs used in this analysis, and those were previously unknown to UniSTS, have now been assigned permanent public UniSTS identifiers. Mapping and descriptive data for each primer pair are available at the publicly accessible dbMHC microsatellite resource: http://www.ncbi.nlm.nih.gov/projects/mhc/xslcgi.fcgi?cmd=mssearch
14th International HLA and Immunogenetics Workshop: Report on the HLA component of type 1 diabetes
Authors: Steenkiste A. , Valdes A. M. , Feolo M. , Hoffman D. , Concannon P. , Noble J. , Schoch G. , Hansen J. , Helmberg W. , Dorman J. S. , Thomson G. , Pugliese A. ,   13th IHWS 1 Diabetes Component participating investigators
Published: April 2007

The type 1 diabetes (T1D) component of the 13th International Histocompatibility Workshop (IHW) obtained microsatellite (msat) and human leukocyte antigen (HLA)‐DR/DQ data on case/control and family samples through an international collaboration. The aim was to detect the effects of susceptibility loci on the HLA complex independent of the primary determinants in the class II region (HLA‐DR/DQ). As part of the activity of the 14th International HLA and Immunogenetics Workshop (14th IHIWS), a T1D workshop was held to present analyses of the 13th IHW data and to discuss the current status of knowledge about the genetics of T1D. These data are now available online through dbMHC, a web‐based resource established by the National Center for Biotechnology. Continuing work since the 13th IHW has resulted in published work showing heterogeneity of DR3 haplotypes in data sets from the 13th IHW and Human Biological Data Interchange (HBDI). In addition, we identified markers that define DRB1*1501 DQB1*0602 haplotypes conferring reduced protection from diabetes in a Swedish 13th IHW data set. Further analyses of the 13th IHW data set not only showed some significant results but also demonstrated extensive heterogeneity reminiscent of non‐HLA genes. The haplotype analysis in HBDI families identified two msats with significant effects on susceptibility and statistically significant age of onset effects at class III markers that are not because of linkage disequilibrium, with class I alleles known to affect age of onset. The above studies underscore the importance of refining our understanding of susceptibility associated with genes in the HLA complex.