bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential haplotype amplification leads to misgenotyping of heterozygote as homozygote when using single nucleotide mismatch primer
Authors: Sarkar Navonil De , Majumder Mousumi , Roy Bidyut
Published: September 2012

Mismatches at the 3′end of /or within a primer are reported to affect the efficiency of PCR and cause allele drop. Here, we report preferential amplification of one haplotype and misgenotyping, when double heterozygotes at NAT1 (rs1057126 and rs15561) were genotyped by sequencing and PCR‐RFLP methods using mismatch reverse primers located next to the target SNP. Detailed study revealed highest (100%) and lowest (0%) misgenotyping when the mismatch was at the 3rd and 15th nucleotide positions from 3′ end of the primer, respectively. But, the same primers, without any mismatch genotyped heterozygotes correctly. Homozygotes can always be detected correctly irrespective of mismatch position in the primer. Similar results were observed for two SNPs (rs12947788 and rs 12951053) at TP53. Using mismatch NAT1 reverse primers, located three nucleotides away from the target SNP, both TaqMan and sequencing methods showed preferential synthesis of one haplotype strand and misgenotyping in heterozygotes, respectively. So, mismatch primer, located next to target SNP, should be avoided to genotype heterozygotes, since, PCR and sequencing based genotyping methods may lead the investigators to report faulty allelic and genotypic frequencies. This study mimics a situation when an unknown variation is present in the primer‐binding sites of both chromosomes.
Dose‐response analysis of bromate‐induced DNA damage and mutagenicity is consistent with low‐dose linear, nonthreshold processes
Authors: Spassova Maria A. , Miller David J. , Eastmond David A. , Nikolova Nadejda S. , Vulimiri Suryanarayana V. , Caldwell Jane , Chen Chao , White Paul D.
Published: September 2012

Mutagenic agents have long been inferred to act through low‐dose linear, nonthreshold processes. However, there is debate about this assumption, with various studies interpreting datasets as showing thresholds for DNA damage and mutation. We have applied rigorous statistical analyses to investigate the shape of dose‐response relationships for a series of in vitro and in vivo genotoxicity studies using potassium bromate (KBrO3), a water ozonation byproduct that is bioactivated to a reactive species causing oxidative damage to DNA. We analyzed studies of KBrO3 genotoxicity where no‐effect/threshold levels were reported as well as other representative datasets. In all cases, the data were consistent with low‐dose linear models. In the majority of cases, the data were fit either by a linear (straight line) model or a model which was linear at low doses and showed a saturation‐like downward curvature at high doses. Other datasets with apparent upward curvature were still adequately represented by models that were linear at low dose. Sensitivity analysis of datasets showing upward curvature revealed that both low‐dose linear and nonlinear models provide adequate fits. Additionally, a simple biochemical model of selected key processes in bromate‐induced DNA damage was developed and illustrated a situation where response for early primary events suggested an apparent threshold while downstream events were linear. Overall, the statistical analyses of DNA damage and mutations induced by KBrO3 are consistent with a low‐dose linear response and do not provide convincing evidence for the presence of a threshold. Environ. Mol. Mutagen., 2013. © 2012 Wiley Periodicals, Inc.
Validation of a treatment algorithm for major depression in an older Brazilian sample
Authors: Ribeiz Salma R. I. , Ávila Renata , Martins Camila B. , Moscoso Marco A. A. , Steffens David C. , Bottino Cássio M. C.
Published: September 2012

Objective

The aim of this study was to investigate the effectiveness of a modified version of the Duke Somatic Algorithm Treatment for Geriatric Depression (STAGED) in a Brazilian sample of older patients with major depression. Besides, we aimed to investigate possible baseline predictive factors for remission in this sample.

Methods

Sixty‐seven depressed individuals were treated according to STAGED over 24 weeks in a prospective cohort design with follow‐up. All patients had criteria for major depression and were at least 60 years of age at baseline enrollment.

Results

During this follow‐up, 56 patients could be classified in remitted or not remitted group, 42.85% reached remission, and 57.14% did not reach remission. These results are even better than those found in the original study, probably due to the lower baseline depression severity of our sample. When baseline characteristics were compared between remitted and not remitted groups, scores of Mini Mental State Examination and Cambridge Cognitive Examination (CAMCOG) were the only variables with statistical significant difference (p < 0.05) between groups. Logistic regression analysis was carried out to try to predict remission and statistical significance (p < 0.05) was found only for baseline MMSE scores. It may mean that patients with mixed cognitive disorders and mood disorders have a worse course of depression.

Conclusions

This version of STAGED seems to be a useful strategy for treatment of depression in late life. Baseline general cognitive performance might be useful to predict remission of depression in older patients with mild to moderate depression. Further research with different population characteristics should be conducted in order to evaluate its usefulness and feasibility in different settings. Copyright © 2012 John Wiley & Sons, Ltd.
Evaluation of a horseradish peroxidase‐catalyzed process for triclosan removal and antibacterial activity reduction
Authors: Melo C. F. , Dezotti M.
Published: September 2012

BACKGROUND: Triclosan is a biocide used in personal care products, and its presence in water bodies has been reported. This compound is suspected to be linked with the emergence of antibiotic‐resistant bacteria. In the present work, the enzyme horseradish peroxidase (HRP) was used to catalyze triclosan removal.

RESULTS: The stoichiometric ratio of H2O2 to triclosan (0.83) was higher than the value predicted by the HRP catalytic cycle (0.5). During the reactions, HRP activity was gradually reduced, likely due to excess H2O2. The addition of veratryl alcohol, syringaldazine and p‐coumaric acid (redox mediators) to the reaction medium, at a mediator/triclosan molar ratio of 1.0, increased triclosan removal from 45% (without a mediator) to 56%, 64% and 80%, respectively. The antibacterial activity of these mediators was much lower than that observed for triclosan.

CONCLUSION: The antibacterial activity of triclosan solution was effectively reduced after enzymatic treatment. Moreover, the enzymatic process was proven to be technically feasible for removing triclosan at an environmental relevant concentration. © 2012 Society of Chemical Industry
Effect of porous media types on oil recovery by indigenous microorganisms from a Mexican oil field
Authors: Roldán‐Carrillo Teresa , Castorena‐Cortés Gladys , Reyes‐Avila Jesús , Zapata‐Peñasco Icoquih , Olguín‐Lora Patricia
Published: September 2012

Background

Several studies on oil recovery using a packed system have been reported; however, the majority use Berea (quartz). In Mexico, more than 37% of the proven reserves are found in reservoirs formed of carbonate and quartz rocks. In this study, the effects on microbial oil recovery of three types of porous media were evaluated: carbonate (Lm), quartz (Ot), and rock from a Mexican oil reservoir (Ch), formed of carbonate (45%) and quartz (38%).

Results

Oil recovery experiments using granulated porous media saturated with oil and two mixed cultures (AF1 and AF2) from a Mexican oil field, were assessed at 70°C under anaerobic conditions. Microbial cultures were composed of thermophilic, fermentative microorganisms, including Thermoanaerobacter, Natronovirga and Geothermobacterium, among others. Biomass production (150–240 mg L–1), substrate consumption (0.1 mg L–1 h–1) and CO2 production (0.10–0.28 mmol L–1) were measured. The systems presented significant differences in recovery (P= 0.000006), and carbonated systems presented the highest oil recovery; the best system combining the AF2 culture with porous medium from a Mexican reservoir (Ch) composed mainly of carbonate, achieving an oil recovery of 23.8%.

Conclusion

The efficiency of microbial enhanced oil recovery is dependent on the inoculum and the type of porous medium.
Aqua oxyhydroxycarbonate second phases at the surface of Ba/Sr‐based proton conducting perovskites: a source of confusion in the understanding of proton conduction
Authors: Colomban Ph. , Tran C. , Zaafrani O. , Slodczyk A.
Published: September 2012

Ba/Sr‐based zirconates and cerates appear as potential proton conducting electrolytes for water electrolysers, hydrogen fuel cells and CO2/syngas converters. Such application requires long lifetime of each components: a good chemical and thermal stability of the device core and a low reactivity of the electrolyte membrane. It has been recently revealed that the complex infrared (IR) and Raman signatures observed for series of zirconates, cerates and/or titanates, assigned by some authors to the bulk protonic species actually arose from the surface species in the form of second undesirable phases: the high dense proton conducting ceramics being free from such signatures. In order to contribute to a better characterization of the phases that can be formed on the surface of proton conducting ceramics, we analysed the IR and Raman spectra of Ba/SrO, Ba/Sr(OH)2, Ba/SrCO3 in their dry and hydrated/deuterated forms in combination with thermogravimetric analysis. The results allowed us to confirm the above claim and to re‐assign the vibrational spectra of perovskite materials wrongly attributed to the bulk protonic species. Since these second phases exhibit a high proton conductivity, their presence is very detrimental in the determination of intrinsic electrolyte bulk properties and interpretation of the conduction mechanisms. Copyright © 2012 John Wiley & Sons, Ltd.
Influence of oligonucleotide interaction on electronic properties of single walled carbon nanotubes
Authors: Ayaksız Ozturk Sevcan , Kelestemur Seda , Culha Mustafa
Published: September 2012

Raman spectroscopy is a powerful tool to study molecular systems. The influence of the non‐covalent interactions of two different lengths of oligonucleotides, 10‐base and 25‐base, composed of polyA, polyT, polyG and polyC, on the electronic structure of single‐walled carbon nanotubes (SWCNTs) is first studied by means of Raman spectroscopy. Then, the possible changes in their electronic structure with chemical attachment of the oligonucleotides are investigated. The Raman data indicates that polyA with 10‐base wraps the SWCNTs at increased incubation time, while polyA with 25‐base wraps quickly, but increasing the incubation time reduces the efficient wrapping, possibly due to the self‐stacking. The polyT‐10 does not wrap around the SWCNTs very effectively even at increased incubation times, but the polyT‐25 wraps them effectively in 30 mins, but increasing the time again decreases the wrapping significantly. While polyG shows similar pattern to the case for the polyA, the polyC shows much higher affinity for the SWCNTs under all studied conditions. The chemical attachment of the same oligonucleotides does not alter the electronic properties of the SWCNTs significantly. These results suggest that oligonucleotides can be used to bring the SWCNTs into higher structures through DNA hybridization without significantly altering their unique properties. Copyright © 2012 John Wiley & Sons, Ltd.
Current trends in international occupational therapy practice
Authors: Punwar Alice
Published: September 2012

Occupational therapy has grown and developed into an international field with 43 national associations holding membership in the World Federation of Occupational Therapists (WFOT). This paper reviews the development of WFOT, describes the status of occupational therapy in selected WFOT member countries, and discusses worldwide health problems and current trends in international occupational therapy practice.
Predictors of burden in mothers of physically disabled children
Authors: Tetreault Sylvie , Weiss‐Lambrou Rhoda , Vezina Aline
Published: September 2012

The impact a physically disabled child has on the family, particularly the impact of the child on the mother's burden, is a relatively unexplored area of study in the literature. The purpose of the present study was to identify which factors are significantly associated with the burden perceived by mothers of a disabled child. Seventy‐four mothers who had a child with a physical disability, living in Québec, Canada, completed four self‐administered questionnaires which examined certain characteristics of the mother, the child and the environment in relation to burden. The statistical analysis of the data revealed four predictors of burden in mothers of a physically disabled child: the amount of time the mother spent on caregiving, the secondary health problems of the child, the number of years of marriage and the mother's use of specific coping strategies. The findings are discussed in terms of their clinical implications for occupational therapists and recommendations for future studies are proposed.
The quality of occupational therapy evaluated in six outpatients
Authors: Söderback Ingrid , Pekkanen Kerstin , Riedel Dorothee , Krakau Ingvar , Gruvsved Åsa , Härtull Marina , Kratz Gunvor , Lind Anna , Lassfolk Anita
Published: September 2012

The purpose of the study was to analyse the content and evaluate the quality of clinical occupational therapy in outpatients as reported by their respective therapists. An inductive and interpretive technique with special study protocols was developed in Sweden for the study of six patients. Each therapist kept a protocol of the patient's 2–3 months' participation in occupational therapy. The protocols were subsequently interpreted independently by another occupational therapist and a physician. At the end of the study, function and ability had improved in four cases and quality of life in five out of six cases as demonstrated by their ability in activities of daily living.
Qualitative research with people with intellectual disability
Authors: Llewellyn Gwynnyth
Published: September 2012

Qualitative research methods are gaining popularity in disability research, in particular as a way to explore the personal experience of disability. However, using these methods can be problematic with people traditionally regarded as vulnerable in the research relationship. People with intellectual disability are often so regarded. This paper discusses ethical concerns and issues of research credibility in qualitative research with this group of disabled people. An ethnographic study about the parenting experience of parents with intellectual disability is used to illustrate strategies to achieve credibility in qualitative studies in intellectual disability research.
Methodology for validating the translation of test measurements applied to occupational therapy
Authors: Hachey Raymonds , Jumoorty Jennifer , Mercier Celine
Published: September 2012

There are many evaluations for assessing English‐speaking patients but few standardised instruments exist in other languages. A description of the methodology and procedures for validating the translation of the ‘Role Checklist’ is presented. A research study was conducted, with individuals having a severe mental health disability, using the Role Checklist as the instrument to be validated into French. This checklist assesses productive roles in adult life by indicating the individual's perception of his or her past, present, future roles. The results regarding the reliability and validity of the French version will be discussed. Although the overall results of the French version are good, part 2 of the instrument should be used with caution.
A case study applying a psychodynamic approach to occupational therapy
Authors: Benetton M.J.
Published: September 2012

By means of a case study, the author presents the most important methodological and technical aspects used to treat patients with psychosis in occupational therapy based on a psychodynamic approach. This study results fundamentally from the connection of three stories each one with its main character. In the first story, the main character is a psychiatric patient (a 20‐year‐old young man having the diagnosis of paranoid schizophrenia). In the second story, the main character is ‘occupational therapy in mental health’ (emphasis is put on the psychodynamic approach). In the third story, the main character is an occupational therapist who works in her private office. I hope this study illustrates the constitution of an occupational therapy technique in mental health.
Polymer brushes on flat and curved surfaces: How computer simulations can help to test theories and to interpret experiments
Authors: Binder K. , Milchev A.
Published: September 2012

Theoretical descriptions of static properties of polymer brushes are reviewed, with an emphasis on monodisperse macromolecules grafted to planar, cylindrical, or spherical substrates. Blob concepts and resulting scaling relations are outlined, and various versions of the self‐consistent field theory are summarized: the classical approximation and the strong stretching limit, as well as the lattice formulation. The physical justification of various inherent assumptions is discussed, and computer simulation results addressing the test of the validity of these approximations are reviewed. Also, alternative theories, such as the single chain mean field theory and the density functional theory, are briefly mentioned, and the main facts about the models used in the computer simulations are summarized. Both molecular dynamics and Monte Carlo simulations are described, the latter including lattice models and bead‐spring models in the continuum. Also extensions such as brush–brush interactions or nanoparticles inside of brushes as well as the solubility of free chains in brushes are briefly mentioned. Pertinent experimental results, though still somewhat scarce, are mentioned throughout and their consequences on the status of the theoretical understanding of polymer brushes is emphasized. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Student empowerment in an environmental science classroom: Toward a framework for social justice science education
Authors: Dimick Alexandra Schindel
Published: September 2012

Social justice education is undertheorized in science education. Given the wide range of goals and purposes proposed within both social justice education and social justice science education scholarship, these fields require reconciliation. In this paper, I suggest a student empowerment framework for conceptualizing teaching and learning social justice science education in classroom settings. I utilize this framework to analyze the case study of a high school environmental science classroom in the United States where the teacher and students created environmental action projects that were relevant to their community. I examine how social, political, and academic empowerment were or were not enacted within the classroom and argue for educators to give heed to all three simultaneously to mediate student empowerment while working toward social justice science education. © 2012 Wiley Periodicals, Inc. Sci Ed 96: 990–1012, 2012
Light‐Governed Capillary Flow in Microfluidic Systems
Authors: Jiang Li , Erickson David
Published: September 2012

Light‐based flow systems for point‐of‐care devices are of interest because, in principle, sunlight could be used to operate them, potentially allowing for high functionality with minimal device complexity and expense. A light‐operated method to drive flow using poly(N‐isopropylacrylamide), a ‘smart’ polymer that changes wettability as a function of temperature, is introduced. It is grafted onto a carbon black‐polydimethylsiloxane surface, which converts light into a thermal pattern that valves flow at user‐defined locations. Flow rates are demonstrated ranging from 4 μL min−1 at 25 °C to 0.1 μL min−1 at 40 °C. The valving dynamics are also characterised, and a response time of less than 4 s is shown. Light‐operated flow could provide the simple architecture and advanced functionality needed in low‐resource point‐of‐care devices.
A protocol to compare nestedness among submatrices
Authors: Strona Giovanni , Stefani Fabrizio , Galli Paolo , Fattorini Simone
Published: September 2012

Searching for nestedness has become a popular exercise in community ecology. Significance of a nestedness index is usually evaluated using z values, and finding that a matrix is nested is typically a common result. However, nestedness is not likely to be spread uniformly within a matrix of species presence/absence per site. Selected parts of the matrix may show a degree of nestedness significantly higher (or lower) than expected from the overall pattern. Here we describe a procedure to assess if a particular submatrix (i.e., a peculiar combination of rows and columns extracted from the complete matrix) is more or less nested than expected for an assortment of sites and species taken at random from the same overall matrix. The idea is to obtain several submatrices of different sizes from the same overall matrix and to calculate their z values. A regression is then performed between z values of submatrices and their sizes. A nestedness index independent of matrix size is suggested as the deviation of the z value of a particular submatrix from that expected according to the regression line. We applied our protocol to 55 matrices with different nestedness indices under various null‐models and, for purpose of demonstration, we discussed in detail a single case study regarding various animal groups of the Aegean Islands (Greece). The obtained results strongly encourage further research to focus not only on the question whether a matrix is nested or not, but also on where and why nestedness is confined.
Affordances for second language learning in World of Warcraft
Authors: Rama Paul S. , Black Rebecca W. , van Es Elizabeth , Warschauer Mark
Published: September 2012

What are the affordances of online gaming environments for second language learning and socialization? To answer this question, this qualitative study examines two college-age Spanish learners’ experiences participating in the Spanish language version of the massively multi-player online game World of Warcraft. Using data culled from participant observation, interviews, logs of in-game chat, and student journal entries, we describe how the design of the game, cultural norms for its use, and participants’ own abilities interact to afford distinct opportunities for language learning for these two students. Discussion focuses on how online games might be used for language teaching and learning in ways that take full advantage of the medium's affordances for both experienced and inexperienced players.
Calculation of measurement uncertainty for cellulose based transformed board material in tensile testing
Authors: Fank S. , Aydemir B.
Published: September 2012

Today’s global economy obliges manufacturers to produce their products in high quality with cheaper cost. Thus, manufacturers must develop their products applying tests to get better performance and higher quality before distributing them to the competitive market. In order to produce long working life of transformer reactors without losing their performance, different tests including axial and flexural testing are applied on the cellulose based laminated board material used in production. During development of laminated board material, test results should be known very well and the measurement uncertainty of tensile tests should be calculated taking into account all parameters. In this study, effective parameters on the quality of tensile testing causing an increase on the measurement uncertainty are investigated. Tensile strength and elongation test of laminated board material were carried out according to IEC 60641-2 and the uncertainty contributions based on experimental results were calculated. The results and impact of the uncertainty parameters are presented in detail.
Three-dimensional wake transition behind an inclined flat plate
Authors: Yang Dan , Narasimhamurthy Vagesh D. , Pettersen Bjørnar , Andersson Helge I.
Published: September 2012

Transition phenomena in the wake of a flat plate at 25° angle of attack are investigated by means of three-dimensional computer simulations. The Strouhal number versus Reynolds number relationship was determined for Re from 275 to 800. The Strouhal number turned out to be independent of the Reynolds number for Re > 400 and distinctly lower than that reported from recent two-dimensional simulations. A first subharmonic frequency was detected already at Re = 300, at which the originally two-dimensional wake also became three-dimensional. The spanwise wavelength of the most energetic three-dimensional mode turned out to be about two times the projected width of the plate and almost independent of Re. The complexities of the vortex shedding increased gradually with increasing Reynolds number until a turbulent-like state with a continuous spectrum of spanwise scales was found. However, while a strict spanwise periodicity was observed for Re = 350, a more irregular wake topology occurred at Re = 325 with two distinctly different spanwise wavelengths along the span of the plate. The spectral energy of the subharmonic frequency of the longer of these wavelengths was the dominating one.
Pronounced Purcell enhancement of spontaneous emission in CdTe/ZnTe quantum dots embedded in micropillar cavities
Authors: Jakubczyk T. , Pacuski W. , Smoleński T. , Golnik A. , Florian M. , Jahnke F. , Kruse C. , Hommel D. , Kossacki P.
Published: September 2012

The coupling of CdTe/ZnTe quantum dot (QD) emission to micropillar cavity eigenmodes in the weak coupling regime is demonstrated. We analyze photoluminescence spectra of QDs embedded in monolithic micropillar cavities based on Bragg mirrors which contain MgSe/ZnTe/MgTe superlattices as low-index material. The pillar emission shows pronounced cavity eigenmodes, and their spectral shape is in good agreement with simulations. QD emission in resonance with the cavity mode is shown to be efficiently guided toward the detector, and an experimental Purcell enhancement by a factor of 5.7 is determined, confirming theoretical expectations.
The importance of cantilever dynamics in the interpretation of Kelvin probe force microscopy
Authors: Satzinger Kevin J. , Brown Keith A. , Westervelt Robert M.
Published: September 2012

A realistic interpretation of the measured contact potential difference (CPD) in Kelvin probe force microscopy (KPFM) is crucial in order to extract meaningful information about the sample. Central to this interpretation is a method to include contributions from the macroscopic cantilever arm, as well as the cone and sharp tip of a KPFM probe. Here, three models of the electrostatic interaction between a KPFM probe and a sample are tested through an electrostatic simulation and compared with experiment. In contrast with previous studies that treat the KPFM cantilever as a rigid object, we allow the cantilever to bend and rotate; accounting for cantilever bending provides the closest agreement between theory and experiment. We demonstrate that cantilever dynamics play a major role in CPD measurements and provide a simulation technique to explore this phenomenon.
Cross-plane electronic and thermal transport properties of p-type La0.67Sr0.33MnO3/LaMnO3 perovskite oxide metal/semiconductor superlattices
Authors: Jha Pankaj , Sands Timothy D. , Cassels Laura , Jackson Philip , Favaloro Tela , Kirk Benjamin , Zide Joshua , Xu Xianfan , Shakouri Ali
Published: September 2012

Lanthanum strontium manganate (La0.67Sr0.33MnO3, i.e., LSMO)/lanthanum manganate (LaMnO3, i.e., LMO) perovskite oxide metal/semiconductor superlattices were investigated as a potential p-type thermoelectric material. Growth was performed using pulsed laser deposition to achieve epitaxial LSMO (metal)/LMO (p-type semiconductor) superlattices on (100)-strontium titanate (STO) substrates. The magnitude of the in-plane Seebeck coefficient of LSMO thin films (<20 μV/K) is consistent with metallic behavior, while LMO thin films were p-type with a room temperature Seebeck coefficient of 140 μV/K. Thermal conductivity measurements via the photo-acoustic (PA) technique showed that LSMO/LMO superlattices exhibit a room temperature cross-plane thermal conductivity (0.89 W/m·K) that is significantly lower than the thermal conductivity of individual thin films of either LSMO (1.60 W/m·K) or LMO (1.29 W/m·K). The lower thermal conductivity of LSMO/LMO superlattices may help overcome one of the major limitations of oxides as thermoelectrics. In addition to a low cross-plane thermal conductivity, a high ZT requires a high power factor (S2σ). Cross-plane electrical transport measurements were carried out on cylindrical pillars etched in LSMO/LMO superlattices via inductively coupled plasma reactive ion etching. Cross-plane electrical resistivity data for LSMO/LMO superlattices showed a magnetic phase transition temperature (TP) or metal-semiconductor transition at ∼330 K, which is ∼80 K higher than the TP observed for in-plane resistivity of LSMO, LMO, or LSMO/LMO thin films. The room temperature cross-plane resistivity (ρc) was found to be greater than the in-plane resistivity by about three orders of magnitude. The magnitude and temperature dependence of the cross-plane conductivity of LSMO/LMO superlattices suggests the presence of a barrier with the effective barrier height of ∼300 meV. Although the magnitude of the cross-plane power factor is too low for thermoelectric applications by a factor of approximately 10−4—in part because the growth conditions chosen for this study yielded relatively high resistivity films—the temperature dependence of the resistivity and the potential for tuning the power factor by engineering strain, oxygen stoichiometry, and electronic band structure suggest that these epitaxial metal/semiconductor superlattices are deserving of further investigation.
Photoluminescence spectroscopy and energy-level analysis of metal-organic-deposited Ga2O3:Cr3+ films
Authors: Tokida Yoshinori , Adachi Sadao
Published: September 2012

The aims of this study are (i) to demonstrate the synthesis of Cr3+-activated β-Ga2O3 films by metal-organic deposition and (ii) to report the temperature-dependent photoluminescence (PL) properties of such films from 20 to 300 K. An activation energy of ∼0.9 eV for the Cr3+ ions in β-Ga2O3 is determined from a plot of PL intensity vs calcination temperature. The red-line emission doublet R1 and R2 at ∼1.8 eV and the broad emission band with a peak at ∼1.7 eV are ascribed to the Cr3+ ions in the β-Ga2O3 host. The energies of the excited states, i.e., 2E, 4T2, 2T2, 4T1, and 4T1, in Cr3+ are determined from the experimental PL and PL excitation spectra using a newly developed analysis model. The high-energy luminescence tail of the broad 4T2 → 4A2 emission band can be explained by the hot-carrier effect of the photoexcited electrons in the 4T2 state. The relative intensities of the R-line emission doublet can also be explained very well by the population and depopulation of the electron numbers in the E¯ (R1) and 2A¯ (R2) states. PL properties, such as the temperature-dependent PL intensity, peak energy, and spectral width, are analyzed in detail.
Partial molar quantity of an intensive mother function
Authors: Koga Yoshikata
Published: September 2012

A new formal definition is given to the partial molar quantity of a component i for an intensive mother function. We perturb the entire system by increasing the amount of the target component by δni keeping others constant and measure the response of the system in terms of an intensive mother function, Φ, δΦ. We then define its partial molar quantity of the ith component, ϕi, as ϕi = [δΦ/{δni/(N + δni)]] in the limit of δni → 0. Thus, the physical meaning of ϕi is the effect of the ith component (only) on Φ of the system, just as the partial molar quantity for an extensive mother function. This new formal definition could serve as a starting point for statistical mechanics development of a microscopic connection to the third derivatives of G. We show a number of examples such as an enthalpic inter-solute interaction, a partial molar S-V cross fluctuation density of solute, their analogues, and an excess partial molar absorptivity of solute. These examples were used for studying the nature of aqueous solutions without realizing their formal definition and were instrumental in advancing our understandings.
Role of electropores on membrane blebbing—A model energy-based analysis
Authors: Joshi R. P. , Hu Q.
Published: September 2012

Cell blebbing has been observed invitro in the context of external intense electric field pulsing of biological cells. Here, we propose that this is promoted in part by the formation of electropores that influence the membrane tension. Model energy-based calculations of bleb formation are presented. It is shown that the high density of electropores (with radii around 1 nm) driven by a nanosecond voltage pulse could lead to quasi-stable 1 μm blebs, and that the preferred site for bleb formation would predominantly be near the polar caps facing the electrodes. This is in keeping with recent experimental reports. Our study has implications to pore closing and their lifetimes, an aspect important for intracellular drug delivery.
Digital discrimination of neutrons and gamma-rays in organic scintillation detectors using moment analysis
Authors: Xie Xufei , Zhang Xing , Yuan Xi , Chen Jinxiang , Li Xiangqing , Zhang Guohui , Fan Tieshuan , Yuan Guoliang , Yang Jinwei , Yang Qingwei
Published: September 2012

Digital discrimination of neutron and gamma-ray events in an organic scintillator has been investigated by moment analysis. Signals induced by an americium-beryllium (Am/Be) isotropic neutron source in a stilbene crystal detector have been sampled with a flash analogue-to-digital converter (ADC) of 1 GSamples/s sampling rate and 10-bit vertical resolution. Neutrons and gamma-rays have been successfully discriminated with a threshold corresponding to gamma-ray energy about 217 keV. Moment analysis has also been verified against the results assessed by a time-of-flight (TOF) measurement. It is shown that the classification of neutrons and gamma-rays afforded by moment analysis is consistent with that achieved by digital TOF measurement. This method has been applied to analyze the data acquired from the stilbene crystal detector in mixed radiation field of the HL-2A tokamak deuterium plasma discharges and the results are described.
Thermoelectric properties of YBa2Cu3O7−δ–La2/3Ca1/3MnO3 superlattices
Authors: Heinze S. , Habermeier H.-U. , Cristiani G. , Blanco Canosa S. , Le Tacon M. , Keimer B.
Published: September 2012

We report measurements of the thermoelectric power and electrical resistivity of superlattices composed of the high-temperature superconductor YBa2Cu3O7−δ (YBCO) and the metallic ferromagnet La2/3Ca1/3MnO3 (LCMO) with individual layer thicknesses between 5 and 50 nm. Whereas YBCO and LCMO reference films prepared under the same conditions exhibit negative Seebeck coefficients, in excellent agreement with data on bulk compounds of identical composition, those of all superlattices are positive, regardless of the individual layer thickness. Having ruled out lattice strain and incomplete oxygenation, we attribute the observed sign reversal of the Seebeck coefficient to a long-range electronic reconstruction nucleated at the YBCO-LCMO interfaces.
Interactions between active particles and dynamical structures in chaotic flow
Authors: Khurana Nidhi , Ouellette Nicholas T.
Published: September 2012

Using a simple model, we study the transport dynamics of active, swimming particles advected in a two-dimensional chaotic flow field. We work with self-propelled, point-like particles that are either spherical or ellipsoidal. Swimming is modeled as a combination of a fixed intrinsic speed and stochastic terms in both the translational and rotational equations of motion. We show that the addition of motility to the particles causes them to feel the dynamical structure of the flow field in a different way from fluid particles, with macroscopic effects on the particle transport. At low swimming speeds, transport is suppressed due to trapping on transport barriers in the flow; we show that this effect is enhanced when stochastic terms are added to the swimming model or when the particles are elongated. At higher speeds, we find that elongated swimmers tend be attracted to the stable manifolds of hyperbolic fixed points, leading to increased transport relative to swimming spheres. Our results may have significant implications for models of real swimming organisms in finite-Reynolds-number flows.
Schottky barrier height of Au on the transparent semiconducting oxide β-Ga2O3
Authors: Mohamed M. , Irmscher K. , Janowitz C. , Galazka Z. , Manzke R. , Fornari R.
Published: September 2012

The Schottky barrier height of Au deposited on (100) surfaces of n-type β-Ga2O3 single crystals was determined by current-voltage characteristics and high-resolution photoemission spectroscopy resulting in a common effective value of 1.04 ± 0.08 eV. Furthermore, the electron affinity of β-Ga2O3 and the work function of Au were determined to be 4.00 ± 0.05 eV and 5.23 ± 0.05 eV, respectively, yielding a barrier height of 1.23 eV according to the Schottky-Mott rule. The reduction of the Schottky-Mott barrier to the effective value was ascribed to the image-force effect and the action of metal-induced gap states, whereas extrinsic influences could be avoided.
d
ferromagnetism in undoped n and p-type In2O3 films
Authors: Sun Shaohua , Wu Ping , Xing Pengfei
Published: September 2012

Undoped indium oxide films with room temperature d0 ferromagnetism were prepared by radiofrequency magnetron sputtering with different O2/Ar flux ratio. The optical and magnetic properties changed non-monotonously as the oxygen flux increases. A conversion of conductivity from n-type to p-type was observed as the flux ratio reached 15:15. The concordant results in structural, electrical, optical, and magnetic properties suggest that single ionized oxygen and indium vacancies play crucial roles in mediating the ferromagnetism in n and p-type In2O3 films, respectively.
Highly flexible inverted organic solar cells with improved performance by using an ultrasmooth Ag cathode
Authors: Liu Yue-Feng , Feng Jing , Cui Hai-Feng , Yin Da , Song Jun-Feng , Chen Qi-Dai , Sun Hong-Bo
Published: September 2012

Inverted organic solar cells (OSCs) with high efficiency and flexibility have been demonstrated. A thick Ag film with ultrasmooth morphology fabricated on a photopolymer substrate by template-stripping process and a semitransparent Ag film has been employed as cathode and anode of the top-illuminated OSCs, respectively. An improved performance has been obtained compared with that of the OSCs deposited on Si substrate due to the enhanced charge extraction and reduced charge loss resulted from the employment of the ultrasmooth cathode. Moreover, the flexible OSCs obtained by this method keep good performance under a small bending radius and after repeated bending.
S-parameter and perfect pinning of the Fermi level at nonpolar (11-20) a-plane p-GaN surfaces
Authors: Choi Yunju , Man Song Keun , Kim Hyunsoo
Published: September 2012

We investigated the Schottky barrier height and S-parameter at nonpolar (11-20) a-plane p-GaN surfaces by using Schottky diodes fabricated with various metals, including Ti, Cu, Ni, and Pt. A barrier inhomogeneity model was used to explain anomalous carrier transport behavior at the nonpolar p-GaN surfaces, yielding the mean barrier heights of 2.01, 1.73, 1.82, and 1.92 eV for the Ti, Cu, Ni, and Pt contacts, respectively. The extracted S-parameter was as low as 0.02, indicating perfect pinning of the surface Fermi level at around 1.9 eV above the valence band.
Body size and trophic divergence of two large sympatric elapid snakes (Notechis scutatus and Austrelaps superbus) (Serpentes:Elapidae) in Tasmania
Authors: Fearn S. , Dowde J. , Trembath D. F.
Published: September 2012

Tiger snakes (Notechis scutatus) and lowland copperheads (Austrelaps superbus) are both large viviparous elapid snakes confined to the cooler, mesic regions of southern Australia. In spite of both species being common and widespread in the island state of Tasmania, no quantified studies on the trophic ecology of these two snakes from the main island has been published. During a two-year period we collected field data from 127 adult A. superbus and 74 adult N. scutatus from throughout eastern Tasmania. For both species, males were larger than females with respect to all measured parameters, including mass and head size. Reproduction in females was strongly seasonal and clutch size was not related to maternal body size. N. scutatus has a larger head than A. superbus and consequently ingests both small and large prey. N. scutatus in our study displayed the most catholic diet of any Australian elapid studied to date and consumed mammals (possum, bandicoot, antechinus, rats, mice), birds (fairy wrens), fish (eel, trout) and frogs. A. superbus shows a more specialist diet of large volumes of predominately ectothermic prey (frogs, lizards, snakes) even at maximal sizes and was more likely to contain ingested prey than specimens of N. scutatus. Distinctive rodent bite scars were common on N. scutatus but rare on A. superbus. The high frequency of rodent bite scars on N. scutatus further supports our findings of a primarily endothermic diet for mature specimens. We suggest that significant differences in head size, and hence diet, as well as a taxonomically diverse suite of potential prey in Tasmania allow both these large snakes to coexist in sympatry and avoid interspecific competitive exclusion.
DBL-1, a TGF-β, is essential for
Caenorhabditis elegans
aversive olfactory learning
Authors: Zhang Xiaodong , Zhang Yun
Published: September 2012

The TGF-β superfamily is conserved throughout metazoan, and its members play essential roles in development and disease. TGF-β has also been implicated in adult neural plasticity. However, the underlying mechanisms are not well understood. Here we report that DBL-1, a
Caenorhabditis elegans
TGF-β homolog known to control body morphology and immunity, is essential for aversive olfactory learning of potentially harmful bacteria food. We show that DBL-1 generated by the AVA command interneurons, which are critical for sensorimotor responses, regulates aversive olfactory learning, and that the activity of the type I TGF-β receptor SMA-6 in the hypodermis is needed during adulthood to generate olfactory plasticity. These spatial and temporal mechanisms are critical for the DBL-1 signaling to achieve its diverse functions in development and adult neural plasticity. Interestingly, aversive training decreases AVA calcium response, leading to an increase in the DBL-1 signal secreted from AVA, revealing an experience-dependent change that can underlie the role of TGF-β signaling in mediating plasticity.
TheSalmonellaTyphimurium effector SteC inhibits Cdc42-mediated signaling through binding to the exchange factor Cdc24 inSaccharomyces cerevisiae
Authors: Fernandez-Piñar Pablo , Alemán Ainel , Sondek John , Dohlman Henrik G. , Molina María , Martín Humberto
Published: September 2012

Intracellular survival of Salmonella relies on the activity of proteins translocated into the host cell by type III secretion systems (T3SS). The protein kinase activity of the T3SS effector SteC is required for F-actin remodeling in host cells, although no SteC target has been identified so far. Here we show that expression of the N-terminal non-kinase domain of SteC down-regulates the mating and HOG pathways in Saccharomyces cerevisiae. Epistasis analyses using constitutively active components of these pathways indicate that SteC inhibits signaling at the level of the GTPase Cdc42. We demonstrate that SteC interacts through its N-terminal domain with the catalytic domain of Cdc24, the sole S. cerevisiae Cdc42 guanine nucleotide exchange factor (GEF). SteC also binds to the human Cdc24-like GEF protein Vav1. Moreover, expression of human Cdc42 suppresses growth inhibition caused by SteC. Of interest, the N-terminal SteC domain alters Cdc24 cellular localization, preventing its nuclear accumulation. These data reveal a novel functional domain within SteC, raising the possibility that this effector could also target GTPase function in mammalian cells. Our results also highlight the key role of the Cdc42 switch in yeast mating and HOG pathways and provide a new tool to study the functional consequences of Cdc24 localization.
First Report of Pitch Canker Disease Caused by Rhizosphaera kalkhoffii on Pinus sylvestris in China
Authors: You C. J. , Tian C. M. , Liang Y. M. , Dong X. B. , Tsui C.
Published: September 2012

In November 2010, pitch canker disease was first discovered on Pinus sylvestris var. mongolica Litv. from Daxinganling region in Inner Mongolia Province, China, resulting in severe dieback and bark cracking on the host, accompanied by resin flowing profusely from cankers on the infected branches, cones, and trunks (2). The early stage symptoms consisted of sunken cankers, reddish-brown needles on infected twigs followed by heavy resin soaking of the wood as the disease progressed. Pieces of pitch-soaked wood (3 × 3 mm2) cut from cankerous tissue on branches were surface-sterilized with 0.4% NaOCl for 2 min and then rinsed twice in sterile distilled water. The fragments were placed on potato dextrose agar and incubated at 28°C in the dark. After 7 to 8 days, this process consistently yielded cultures with whitish, dense, aerial mycelium that later darkened to gray. Microconidia were single, oblong to cylindrical, aseptate, and 4 to 10 × 2 to 4 μm. Macroconidia were hyaline, 1- to 2-septate, oblong to cylindrical, with tiny papillae at both ends, and 10 to 13 × 2 to 5 μm, fitting the description of Rhizosphaera kalkhoffii (1). To verify the identification based on morphological features, the internal transcribed spacer (ITS) region of the ribosomal RNA genes was amplified using primers ITS1 (TCCGTAGGTGAACCTGCGG) and ITS4 (TCCTCCGCTTATTGATATGC) according to the published protocol (3), and then sequenced and compared to the GenBank database through BLAST search. Comparison of the sequences revealed 98% homology to R. kalkhoffii (EU700375.1 and EU700376.1). Representative sequences of R. kalkhoffii (JQ353721 and JQ353722) were deposited in GenBank. The pathogenicity of two representative isolates of R. kalkhoffii was also confirmed by spraying 40 μl of conidial suspension (4.6 × 106 conidia/ml) on the bark surface of 20 2-year-old healthy pine seedlings, wounded by scratching with a sterilized knife. Sterile distilled water sprays were used for the controls. Within 4 to 8 weeks after inoculation, 90% of inoculated P. sylvestris exhibited symptoms of pitch cankers around the inoculation site similar to those on the original infection. R. kalkhoffii was consistently reisolated from all inoculated plants but not from water-treated controls, fulfilling Koch's postulates. R. kalkhoffii have previously been documented as pathogens of needle blight of Picea pungens (1). To our knowledge, this is the first report of R. kalkhoffii as a pathogen on Pinus sylvestris in China, and furthermore, pitch canker disease is currently listed as a quarantine disease in China, increasing the significance of this report.

References: (1) J. Kumi et al. Eur. J. Forest Pathol. 9:35, 1979. (2) J. K. Lee et al. Plant Pathol. 16:52, 2000. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.