bluuebunny/crossref_metadata_2025 huggingface dataset:
PIXE analysis of Middle European 18th and 19th century glass seals
Authors: Simon Alíz , Matiskainen Heikki , Uzonyi Imre , Csedreki László , Szikszai Zita , Kertész Zsófia , Räisänen Jyrki , Kiss Árpád Z.
Published: April 2011

Particle‐induced X‐ray emission method was applied for the determination of light and heavy elemental composition of archaeological glass seals. Quantitative information on the major, minor and trace elements and their correlations in respect of the raw materials which were used for the glass manufacturing are discussed. Although the differences of the elemental concentrations between the seals originating from different glassworks were small, discriminant analysis enabled the separation of glassworks to an extent which makes future provenance studies feasible. The need of supplementary use of energy dispersive X‐ray fluorescence and proton‐induced gamma‐ray emission for the glass samples was also investigated. Copyright © 2011 John Wiley & Sons, Ltd.
The identification of plaggen soils using external beam microPIXE analysis
Authors: Grime Geoffrey W. , Guttmann‐Bond Erika
Published: April 2011

Plaggen soils are man‐made agricultural soils which were created in historical times by using peat or turf as animal bedding. This bedding was then spread onto fields to create a rich and unusually deep topsoil. The plaggen system was used in Northern Europe from the Middle Ages up to, in some cases, the 1960s. Plaggen soils can be difficult to distinguish from soils which have simply had manure added, and in this paper we report the use of Proton Induced X‐Ray Emission (PIXE) to investigate the levels of nutrient elements, particularly phosphorus, in soils from a farm in Shetland which is known to have used plaggen soils until 1967. Elemental maps obtained in air using the University of Surrey External Beam system allow us to identify peat fragments which contain significantly elevated levels of phosphorus relative to fresh peat and relative to the surrounding soil matrix. A further finding is that the peat fragments also contain elevated levels of bromine which can be used to distinguish plaggened peat from manure. This technique will be applied to a study of the origins of the plaggen method. Copyright © 2011 John Wiley & Sons, Ltd.
PIXE analysis of a murine solid tumor treated with proton therapy combined with cisplatin
Authors: Terakawa A. , Ishii K. , Yamazaki H. , Matsuyama S. , Kikuchi Y. , Ito Y. , Tagawa A. , Yasunaga S. , Kawamura T. , Takahashi Y. , Hatori Y. , Hamada N. , Fujiki K. , Ito N. , Wada S. , Funaki Y. , Sera K.
Published: April 2011

Platinum concentration in a murine solid tumor treated with proton therapy combined with the platinum‐based chemotherapeutic agent cisplatin [cis‐diamminedichloro‐platinum(II) (CDDP)] was investigated with conventional and submilli‐PIXE (particle‐induced X‐ray emission) analyses. An enhanced therapeutic effect on tumor growth was observed in NFSa fibrosarcoma tumors in mice when proton therapy with a single dose of 30 Gy and CDDP treatment (10 mg/kg) were combined. The conventional PIXE analysis based on an internal standard method showed that the platinum concentration was 2.6 ± 0.3 µg/g for the tumor samples excised from the mice 6 h after the CDDP administration. The submilli‐PIXE analysis of the tumor sections showed that spatial distribution of CDDP may be more or less uniform in the tumor. Copyright © 2011 John Wiley & Sons, Ltd.
CEACAM1 Cytoplastic Expression is Closely Related to Tumor Angiogenesis and Poorer Relapse‐free Survival After Curative Resection of Hepatocellular Carcinoma
Authors: Zhu Jiankang , Yang Yongmei , Ma Chao , Zhang Guangyong , Wang Kexin , Hu Sanyuan
Published: April 2011

Background

The aim of this study was to investigate the expression of carcinoembryonic antigen‐related cell adhesion molecule 1 (CEACAM1) and its effects on tumor angiogenesis and relapse‐free survival (RFS) after curative resection of hepatocellular carcinoma (HCC).

Methods

Expression of CEACAM1 and CD34 was immunohistochemically detected in HCC specimens from 97 patients. Microvessel density (MVD) was determined by counting CD34‐positive endothelial cells. Statistical analyses were performed to determine the effects of CEACAM1 on clinicopathologic factors, tumor angiogenesis, and RFS.

Results

CEACAM1 expression was detected in 91 HCC specimens; 53 cases showed membranous expression and 38 cases showed cytoplastic expression. CEACAM1 cytoplastic expression was significantly associated with tumor size, number of tumors, vascular invasion, satellite nodules, Edmondson–Steiner grade, TNM stage, and MVD (p < 0.05 for all). Moreover, CEACAM1 cytoplastic expression was significantly associated with poorer RFS. The 3‐year RFS of patients with CEACAM1 cytoplastic expression was significantly lower than that of those with CEACAM1 membranous expression (26.3 vs. 52.8%, p = 0.005). Cox analysis revealed that CEACAM1 cytoplastic expression was an independent prognostic factor for 3‐year RFS (p = 0.031).

Conclusion

CEACAM1 expression was common in HCC, and CEACAM1 cytoplastic expression was closely associated with tumor progression, angiogenesis, and poorer RFS, indicating that cytoplastic CEACAM1 might be a predictor of relapsing phenotype and a possible novel target of antiangiogenic therapy for patients with HCC.
Hmong Mental Health Needs Assessment: A Community‐Based Partnership in a Small Mid‐Western Community
Authors: Collier Ann Futterman , Munger Martha , Moua Yong Kay
Published: April 2011

The overall goal of this assessment was to verify the mental health needs of Hmong living in a mid‐west community in order clarify the format, content, and feasibility of providing mental health services for Hmong in the future. Using a Community‐Based Participatory Research (CBPR) model, we held four focus groups with 36 men, women, adolescents and professionals, all of Hmong descent, as well as interviewed 28 individual medical, mental health, education, and social service providers in the Eau Claire community. Our Hmong sample was frequently unclear about what “mental” health meant, indicating a low level of mental health literacy. Results confirmed that there are significant mental health needs in this refugee and immigrant population. Participants described problems consistent with depression, post‐traumatic stress disorder (PTSD), anxiety disorders, somatoform disorders, and severe social stress and acculturation difficulties in every generation. Elder people and male adolescents were described as the most disaffected and in need of immediate services. It will be critical to address mental health literacy before designing future interventions. Treatment suggestions were provided with the intention of removing barriers and incorporating culturally sensitive methodologies, while continuing to work closely with our local mental health providers and Hmong leadership.
Long‐term population dynamics in a Mediterranean aquatic snake
Authors: Luiselli Luca , Madsen Thomas , Capizzi Dario , Rugiero Lorenzo , Pacini Nic , Capula Massimo
Published: April 2011

A review of several long‐term studies has recently suggested that snakes might be declining in large parts of the world. Additional data from other long‐term studies are therefore urgently needed in order to assess the generalities of such suggested declines. Based on a 20‐year study, we analyzed demographic data on adult dice snakes (Natrix tessellata) studied in central Italy between 1985 and 2004. Both male and female dice snakes were relatively long‐lived, with no significant differences in longevity between the sexes. Individual males and females were observed over a maximum of 10 and 14 years, respectively. However, the among‐year recapture rates between the year the snakes were initially captured and the subsequent year (i.e., year 1 to year 2) was significantly lower (45%) than the among‐year recapture rates during subsequent years (74%; i.e., year 2 to year 3), suggesting that a large proportion of the snakes at first capture were in fact not resident within our study area, and hence many snakes were migrating in and out of our 2‐km stream study site, with no inter‐sexual difference in dispersal rates. Sex ratio was virtually equal if we consider the study period as a whole. Significant annual fluctuations were, however, observed through the study. In 1985–1990, 1993–1995, 1998 and 1999 the sex ratio was male‐biased, whereas in 2000–2004 female‐biased. In terms of both survival and recapture probabilities, model selection showed that Akaike's information criterion favored the model incorporating body size, with the model incorporating year having an intermediate likelihood, and the model with sex included being the most disfavored. Total population number estimates suggest an average 86 adult individuals along the 2 km of stream with only minor annual variations. However, a significant decrease in the number of males occurred during the last 6 years of our study. Thus, further monitoring of this population is warranted in light of the decline of snake populations reported recently.
Drug‐resistant malaria: Molecular mechanisms and implications for public health
Authors: Petersen Ines , Eastman Richard , Lanzer Michael
Published: April 2011

Resistance to antimalarial drugs has often threatened malaria elimination efforts and historically has led to the short‐term resurgence of malaria incidences and deaths. With concentrated malaria eradication efforts currently underway, monitoring drug resistance in clinical settings complemented by in vitro drug susceptibility assays and analysis of resistance markers, becomes critical to the implementation of an effective antimalarial drug policy. Understanding of the factors, which lead to the development and spread of drug resistance, is necessary to design optimal prevention and treatment strategies. This review attempts to summarize the unique factors presented by malarial parasites that lead to the emergence and spread of drug resistance, and gives an overview of known resistance mechanisms to currently used antimalarial drugs.
Morphological development of dendritic spines on rat cerebellar Purkinje cells
Authors: Velázquez‐Zamora D.A. , Martínez‐Degollado M. , González‐Burgos I.
Published: April 2011

The posterior cerebellum is strongly involved in motor coordination and its maturation parallels the development of motor control. Climbing and mossy fibers from the spinal cord and inferior olivary complex, respectively, provide excitatory afferents to cerebellar Purkinje neurons. From post‐natal day 19 climbing fibers form synapses with thorn‐like spines located on the lower primary and secondary dendrites of Purkinje cells. By contrast, mossy fibers transmit synaptic information to Purkinje cells trans‐synaptically through granule cells. This communication occurs via excitatory synapses between the parallel fibers of granule cells and spines on the upper dendritic branchlets of Purkinje neurons that are first evident at post‐natal day 21. Dendritic spines influence the transmission of synaptic information through plastic changes in their distribution, density and geometric shape, which may be related to cerebellar maturation. Thus, spine density and shape was studied in the upper dendritic branchlets of rat Purkinje cells, at post‐natal days 21, 30 and 90. At 90 days the number of thin, mushroom and thorn‐like spines was greater than at 21 and 30 days, while the filopodia, stubby and wide spines diminished. Thin and mushroom spines are associated with increased synaptic strength, suggesting more efficient transmission of synaptic impulses than stubby or wide spines. Hence, the changes found suggest that the development of motor control may be closely linked to the distinct developmental patterns of dendritic spines on Purkinje cells, which has important implications for future studies of cerebellar dysfunctions.
Efficacy of iopanoic acid for treatment of spontaneous hyperthyroidism in cats
Authors: Gallagher Alexander E. , Panciera David L.
Published: April 2011

Iopanoic acid is an iodine containing oral cholecystographic agent that has been used to treat hyperthyroidism in humans and has recently been evaluated in an experimental model of feline hyperthyroidism. The aim of this study was to evaluate the efficacy of iopanoic acid in cats with spontaneous hyperthyroidism. Eleven cats were included in the study. Eight were treated initially with 50 mg orally q 12 h and three were treated with 100 mg orally q 12 h. Prior to treatment (baseline) and at 2, 4, and 12 weeks of treatment, owner questionnaires, physical exams, complete blood count, biochemistry analyses, and T3 and T4 concentrations were evaluated. The mean serum T3 concentration decreased with treatment at all time periods compared to baseline. Mean T4 concentrations were increased at weeks 4 and 12 compared to baseline. Five cats had a partial response during the initial 4 weeks of therapy, but the effects were transient and no significant improvements in clinical signs or physical exam findings were noted at any time period. Results suggest that iopanoic acid may be beneficial for acute management of thyrotoxicosis in some cats, but is not suitable for long-term management.
Health‐related quality of life in patients undergoing cholecystectomy
Authors: Hsueh Li‐Na , Shi Hon‐Yi , Wang Tsai‐Fan , Chang Chiung‐Ying , Lee King‐Teh
Published: April 2011

This large‐scale prospective cohort study of a Taiwan population applied generalized estimating equations to evaluate predictors of health‐related quality of life (HRQOL) after open cholecystectomy (OC) and laparoscopic cholecystectomy (LC) procedures performed between February 2007 and November 2008. The Gastrointestinal Quality of Life Index and Short Form‐36 were used in a preoperative assessment and in 3rd month and 6th month postoperative assessments of 38 OC and 259 LC patients. The HRQOL of the cholecystectomy patients were significantly improved at 3 months and 6 months postsurgery (p < 0.05). At 3 months postsurgery, HRQOL improvement was significantly larger in LC patients than in OC patients. Patient characteristics, clinical characteristics, and health care quality were also significantly related to HRQOL improvement (p < 0.05). Additionally, after controlling for related variables, preoperative health status was significantly and positively associated with each subscale of the Gastrointestinal Quality of Life Index and Short Form‐36 throughout the 6 months (p < 0.05). Patients should be advised that their postoperative HRQOL may depend not only on their postoperative health care but also on their preoperative functional status.
Metabolic effects of signal transduction inhibition in cancer assessed by magnetic resonance spectroscopy
Authors: Moestue Siver Andreas , Engebraaten Olav , Gribbestad Ingrid Susann
Published: April 2011

Despite huge efforts in development of drugs targeting oncogenic signalling, the number of such drugs entering clinical practice to date remains limited. Rational use of biomarkers for drug candidate selection and early monitoring of response to therapy may accelerate this process. Magnetic resonance spectroscopy (MRS) can be used to assess metabolic effects of drug treatment both in vivo and in vitro, and technological advances are continuously increasing the utility of this non‐invasive method. In this review, we summarise the use of MRS for monitoring the effect of targeted anticancer drugs, and discuss the potential role of MRS in the context of personalised cancer treatment.
Geschlecht und Gesundheit
Authors: Hurrelmann Klaus , Quenzel Gudrun
Published: April 2011

Einleitung

Nach wie vor werden geschlechtsspezifische Unterschiede in der Gesundheitswahrnehmung, den gesundheitlichen Risikofaktoren und den Krankheitsverläufen häufig unterschätzt. In den Gesundheitswissenschaften gibt es seit Langem Bemühungen, die insgesamt beträchtlichen Unterschiede im Gesundheitszustand und in der Lebenserwartung von Männern und Frauen zu erklären. Hierzu werden sowohl medizinische als auch sozialwissenschaftliche Ansätze herangezogen.
Geschlecht und psychische Störungen
Authors: Möller-Leimkühler Anne Maria
Published: April 2011

Einleitung

Psychische Störungen sind komplexe, multifaktoriell bedingte Erkrankungen, von denen etwa jeder dritte erwachsene Deutsche im Laufe eines Jahres betroffen ist. Sie gehören zu den häufigsten und kostenintensivsten Erkrankungen, insbesondere Angsterkrankungen und Depressionen, die seit den 1990er Jahren zunehmend zu Fehlzeiten, stationären Behandlungen und Frühberentungen führen. Während die Lebenszeitprävalenz psychischer Störungen von Frauen und Männern insgesamt etwa gleich hoch ist, zeigen sich erhebliche Prävalenzunterschiede bei einzelnen psychischen Störungen.
Geschlechtsspezifische genetische Effekte bei komplexen Erkrankungen
Authors: Heid Iris M. , Rehli Michael , Kronenberg Florian
Published: April 2011

Einleitung

„Männer kommen vom Mars und Frauen von der Venus“. Was hinreichend humorigen Gesprächsstoff liefert, besitzt einen medizinisch und gesundheitswissenschaftlich relevanten Hintergrund. Viele Erkrankungen weisen deutliche Geschlechtsunterschiede in Prävalenz, Entstehungsalter oder Schweregrad auf. So tritt Herzinsuffizienz bei Männern häufiger und in eher jüngeren Jahren auf (Regitz-Zagrosek et al., 2010), um nur ein klassisches Beispiel zu nennen. Woher kommen diese Unterschiede? Welcher Anteil dieser Unterschiede ist vererbt, wie viel ist erworben?
Anisotropic viscosity changes subduction zone thermal structure
Authors: Lev Einat , Hager Bradford H.
Published: April 2011

Abundant observations of seismic anisotropy in subduction zones attest that the material in the mantle wedge has a strong fabric and therefore should be mechanically anisotropic. In this paper, we examine the effect of anisotropic viscosity on the thermal structure of subduction zone mantle wedges and quantify its importance relative to other thermal and rheological factors. Using two‐dimensional finite element kinematic models we find that anisotropic viscosity results in two substantial changes: a hotter slab‐wedge interface and time variability of the melt production rate and excess temperatures. Although not as significant as the effect of temperature‐dependent viscosity, anisotropy leads to an increase of up to 35°C in the temperature along the slab‐wedge interface. A hotter slab‐wedge interface can change the depth extent of the seismogenic zone, limit the depth to which hydrous minerals can carry water, and influence flux melting. Time variability of the thermal field is a novel result of adding anisotropic viscosity to our models. This time variability results from heterogeneity in material alignment and could explain temporal changes in subduction zone magmatism without invoking a change in the wedge geometry, slab age, or composition.
Comparison of frictional strength and velocity dependence between fault zones in the Nankai accretionary complex
Authors: Ikari Matt J. , Saffer Demian M.
Published: April 2011

Accretionary complexes host a variety of fault zones that accommodate plate convergence and internal prism deformation, including the décollement, imbricate thrusts, and out‐of‐sequence thrusts or splays. These faults, especially the décollement and major splay faults, are considered to be candidates for hosting slow slip events and large magnitude earthquakes, but it is not clear what modes of slip should be expected at shallow levels or how they are related to fault rock frictional properties. We conducted laboratory experiments to measure the frictional properties of fault and wall rock from three distinct fault zone systems sampled during Integrated Ocean Drilling Program Expedition 316 and Ocean Drilling Program Leg 190 to the Nankai Trough offshore Japan. These are (1) a major out‐of‐sequence thrust fault, termed the “megasplay” (Site C0004), (2) the frontal thrust zone, a region of diffuse thrust faulting near the trench (Site C0007), and (3) the décollement zone sampled 2 km from the trench (Site 1174). At 25 MPa effective normal stress, at slip rates of 0.03–100 μm/s, and in the presence of brine as a pore fluid, we observe low friction (μ ≤ 0.46) for all of the materials we tested; however, the weakest samples (μ ≤ 0.30) are from the décollement zone. Material from the megasplay fault is significantly weaker than the surrounding wall rocks, a pattern not observed in the frontal thrust and décollement. All samples exhibit primarily velocity‐strengthening frictional behavior, suggesting that earthquakes should not nucleate at these depths. A consistent minimum in the friction rate parameter a‐b at sliding velocities of ∼1–3 μm/s (∼0.1–0.3 m/d) is observed at all three sites, suggesting that these shallow fault zones may be likely to host slow slip events.
Extreme rainfall and flooding from orographic thunderstorms in the central Appalachians
Authors: Smith James A. , Baeck Mary Lynn , Ntelekos Alexandros A. , Villarini Gabriele , Steiner Matthias
Published: April 2011

The central Appalachian region has experienced some of the largest rainfall accumulations in the world at time intervals less than 6 h, including the 18 July 1942 Smethport, Pennsylvania, storm that produced 780 mm in less than 5 h. The envelope curve of central Appalachian flood peaks at “small” drainage areas (less than 1000 km2) is dominated by orographic thunderstorm systems, like the Smethport storm. Orographic thunderstorm systems that have produced catastrophic flooding in the central Appalachians are examined through observational and numerical model analyses using the Weather Research and Forecasting (WRF) model. Analyses suggest that the frequency of catastrophic flooding varies over the central Appalachian region and that small‐scale variation may be linked to the role of complex terrain in altering thunderstorm dynamics. Catastrophic flooding along the western margin of the central Appalachians is dominated by four storms that occurred on 18–19 July (1889, 1942, 1977, and 1996), which were associated with warm season extratropical systems and were characterized by rapidly moving storm elements in complex terrain. Along the eastern margin and interior of the central Appalachians, catastrophic flooding is linked to four “terrain‐locked” orographic convective systems that occurred 17–18 June 1949, 18–19 August 1969, 27 June 1995, and 11 August 2003. WRF model simulations of the Little River storm (June 1949), Rapidan storm (June 1995), Smethport storm (18 July 1942) and Redbank storm (18–19 July 1996) are used to characterize “ingredients” of catastrophic rainstorms in the central Appalachians.
High-power, kilojoule laser interactions with near-critical density plasma
Authors: Willingale L. , Nilson P. M. , Thomas A. G. R. , Bulanov S. S. , Maksimchuk A. , Nazarov W. , Sangster T. C. , Stoeckl C. , Krushelnick K.
Published: April 2011

Experiments were performed using the Omega EP laser, which provided pulses containing 1kJ of energy in 9ps and was used to investigate high-power, relativistic intensity laser interactions with near-critical density plasmas, created from foam targets with densities of 3–100 mg/cm3. The effect of changing the plasma density on both the laser light transmitted through the targets and the proton beam accelerated from the interaction was investigated. Two-dimensional particle-in-cell simulations enabled the interaction dynamics and laser propagation to be studied in detail. The effect of the laser polarization and intensity in the two-dimensional simulations on the channel formation and electron heating are discussed. In this regime, where the plasma density is above the critical density, but below the relativistic critical density, the channel formation speed and therefore length are inversely proportional to the plasma density, which is faster than the hole boring model prediction. A general model is developed to describe the channel length in this regime.
Magnetocaloric effect in single crystal Nd2Co7
Authors: Ilyn M. , Bartashevich M. I. , Andreev A. V. , Tereshina E. A. , Zhukova V. , Zhukov A. , Gonzalez J.
Published: April 2011

Single-crystalline sample of Nd2Co7 (TC 613 K) has been used to study “anisotropic” magnetocaloric effect (MCE), originated from field induced rotation of the magnetic moment from easy- to hard-magnetization direction. Anisotropy constants were estimated using measured magnetization isotherms within 200–320 K temperature range, which encompasses two spontaneous spin-reorientation phase transitions. These data allow us to calculate the magnetic entropy and “anisotropic” MCE using simple thermodynamic model. Thus obtained MCE was successfully compared with MCE calculated by means of the Maxwell relation. Main differences between “anisotropic” MCE and MCE concerned with magnetizing of ferromagnetic substances near their Curie temperatures have been revealed. In spite of rather low characteristic values (ΔS = −0.005 MJ/Km3, ΔT = 0.4 K at 235 K and ΔS = 0.005 MJ/Km3, ΔT =− 0.44 K at 250 K on the field change of 1 T) observed in Nd2Co7, intrinsic properties of the “anisotropic” MCE were found to be rather good: it may be a flat function of temperature, rotation of the moment can be completed in the moderate fields, neither temperature nor field hysteresises has been observed. Furthermore, the peak values of the “anisotropic” MCE are not limited by equation restricting MCE in the common ferromagnetic materials.
Discoveries from the exploration of gyrokinetic momentum transport
Authors: Staebler G.M. , Waltz R. E. , Kinsey J. E.
Published: April 2011

The momentum transport due to gyroradius scale turbulence in tokamak plasmas is very complex. In general, some type of breaking of the parity of the gyrokinetic equation under simultaneous reflection of the poloidal angle and the sign of the parallel velocity phase space coordinate (poloidal parity) is always involved. There are three distinct types of poloidal parity breaking effects. In this paper, all three types of poloidal parity breaking are explored using the quasi-linear trapped gyro-Landau fluid [G. M. Staebler et al., Phys. Plasmas 12, 102508 (2005)] transport code. Selected results are verified with full nonlinear turbulence simulations using the gyro [J. Candy et al., J. Comput. Phys. 186, 545 (2003)] gyrokinetic code. The observable properties like an energy pinch driven by a parallel velocity shear and a dependence of momentum transport on the direction of the ion grad-B drift relative to the X-point location in single null divertor geometry have been discovered.
Localized defects closely related with the magnetism of graphite induced by 12C+ ion implantation
Authors: Yang Xin-Mei , He Zhou-Tong , Li Wei-Feng , Xia Hui-Hao , Song You , Zhou Xing-Tai , Liu Xiang-Dong , Zhao Ming-Wen , Wang Tian-Wei , Hou Ke-Yu
Published: April 2011

The magnetism of highly oriented pyrolytic graphite (HOPG) induced by 70 keV 12C+ ion implantation was investigated by using electron spin resonance (ESR) and theoretical simulations of the electronic structure of defective graphite using spin-polarized density functional theory. The results indicate that defects produced by 12C+ ion implantation can induce magnetic moments which are localized since a L1 line is observed at a fixed resonance field, independent of the angle between the field and the c axis of the HOPG sample. The angle and temperature dependence of the ESR spectra indicates that extrinsic carriers are induced in the implanted layer, and they may have an exchange interaction with local spins to produce a single asymmetric L1 line of the implanted sample. The consistent results given by the ESR spectra and the theoretical simulations of the electronic structure of defective graphite provide a clear explanation for the magnetic order in 12C+ ion-implanted HOPG. The defects produced by the implantation induce local magnetic moments in the sample. Due to the interaction between the local spins and the extrinsic carriers, the local magnetic moments may be coupled through the mediation of itinerant carriers.
Interface model for HfO2 gate stack from first principles calculations and its application to nanoscale device simulations
Authors: Shin Mincheol , Park Yongjin , Kong Ki-jeong , Chang Hyunju
Published: April 2011

Rigorous first-principles calculations are performed to address the interface properties of HfO2 gate stacks with interlayer (IL). The band-gap and dielectric constant change nonabruptly at the HfO2/IL and IL/Si interfaces with transition regions of a few angstrom wide. Device-level simulations are then performed with the interface properties reflected, and electrostatics, gate-leakage and drain currents are found to be substantially influenced by the presence of the transition regions. Based on the findings, the equivalent single-layer model as a practical guide to the modeling and simulation of HfO2 gate stacks is proposed.
Linear and nonlinear coupled drift and ion acoustic waves in collisional pair ion–electron magnetoplasma
Authors: Mushtaq A. , Saeed R. , Haque Q.
Published: April 2011

Linear and nonlinear coupled electrostatic drift and ion acoustic waves are studied in inhomogeneous, collisional pair ion–electron plasma. The Korteweg–de Vries–Burgers (KdVB) equation for a medium where both dispersion and dissipation are present is derived. An attempt is made to obtain exact solution of KdVB equation by using modified tanh–coth method for arbitrary velocity of nonlinear drift wave. Another exact solution for KdVB is obtained, which gives a structure of shock wave. Korteweg–de Vries (KdV) and Burgers equations are derived in limiting cases with solitary and monotonic shock solutions, respectively. Effects of species density, magnetic field, obliqueness, and the acoustic to drift velocity ratio on the solitary and shock solutions are investigated. The results discussed are useful in understanding of low frequency electrostatic waves at laboratory pair ion plasmas.
Reaction-diffusion analysis for one-step plasma etching and bonding of microfluidic devices
Authors: Rosso Michel , van Steijn Volkert , de Smet Louis C. P. M. , Sudhölter Ernst J. R. , Kleijn Chris R. , Kreutzer Michiel T.
Published: April 2011

A self-similar reaction front develops in reactive ion etching when the ions penetrate channels of shallow height h. This relates to the patterning of microchannels using a single-step etching and bonding, as described by Rhee et al. [Lab Chip 5, 102 (2005)]. Experimentally, we report that the front location scales as xf∼ht1/2 and the width is time-invariant and scales as δ∼h. Mean-field reaction-diffusion theory and Knudsen diffusion give a semiquantitative understanding of these observations and allow optimization of etching times in relation to bonding requirements.
Low-threshold green laser heterostructures with Zn(Mg)SSe/ZnSe graded-index superlattice waveguide: Structural and optical properties
Authors: Sedova I. V. , Lutsenko E. V. , Gronin S. V. , Sorokin S. V. , Vainilovich A. G. , Sitnikova A. A. , Yablonskii G. P. , Alyamani A. , Fedorov D. L. , Kop’ev P. S. , Ivanov S. V.
Published: April 2011

We report on structural and optical properties of green (λ∼520 nm) ZnCdSe/ZnMgSSe optically pumped laser heterostructures with a Zn(Mg)SSe/ZnSe graded-index superlattice (SL) waveguide, grown by molecular beam epitaxy. The pseudomorphic 400 nm thick waveguide comprising a set of strained ZnMgSSe/ZnSe and ZnSSe/ZnSe SLs of different periods and barrier-to-well thickness ratios at each side of a ZnCdSe quantum well (QW) active region provides efficient transport of nonequilibrium carriers to the QW. This results in reduction in laser threshold down to the extremely low value of 1.5 kW/cm2 at 300 K and increasing the external quantum efficiency above 44%.
Effect of cavity mode volume on photoluminescence from silicon photonic crystal nanocavities
Authors: Nakayama Shigeru , Ishida Satomi , Iwamoto Satoshi , Arakawa Yasuhiko
Published: April 2011

We experimentally investigated photoluminescence (PL) from silicon photonic crystal nanocavities with different mode volumes at room temperature. The integrated cavity mode intensity, which was estimated from the observed PL signal by considering extraction and collection efficiencies for each cavity mode, increased as the cavity mode volume decreased. This result suggests that smaller cavities have larger mode emission efficiency per volume than that for larger cavities at room temperature.
Mechanical analysis and optimization of a microcantilever sensor coated with a solid receptor film
Authors: Yoshikawa Genki
Published: April 2011

This letter presents an analytical model for the static deflection and optimization of a nanomechanical cantilever sensor coated with a solid receptor film. All relevant physical parameters of both cantilever and coating film are included; Young’s modulus, Poisson’s ratio, and geometrical parameters (length, width, and thickness). This model provides accurate values verified by a good agreement with those simulated by finite element analysis, while the Stoney’s equation [G. G. Stoney, Proc. R. Soc. London, Ser. A 82, 172 (1909)] and Sader’s model [J. E. Sader, J. Appl. Phys. 89, 2911 (2001)] which assume ideal surface stress without a solid coating film, result in significant deviation under some conditions. Mechanical analysis and optimization based on experimental results are also demonstrated as an example.
Nanometer-scale epitaxial strain release in perovskite heterostructures using “SrAlOx” sliding buffer layers
Authors: Sato H. K. , Mundy J. A. , Higuchi T. , Hikita Y. , Bell C. , Muller D. A. , Hwang H. Y.
Published: April 2011

We demonstrate the strain release of LaAlO3 epitaxial films on SrTiO3 (001) by inserting ultrathin “SrAlOx” buffer layers. Although SrAlOx is not a perovskite, nor stable as a single phase in bulk, epitaxy stabilizes the perovskite structure up to a thickness of 2 unit cells (uc). At a critical thickness of 3 uc of SrAlOx, the interlayer acts as a sliding buffer layer, and abruptly relieves the lattice mismatch between the LaAlO3 film and the SrTiO3 substrate, while maintaining crystallinity. This technique may provide a general approach for strain relaxation of perovskite films far below the thermodynamic critical thickness.
Graphyne- and graphdiyne-based nanoribbons: Density functional theory calculations of electronic structures
Authors: Pan L. D. , Zhang L. Z. , Song B. Q. , Du S. X. , Gao H.-J.
Published: April 2011

We report on the configurations and electronic properties of graphyne and graphdiyne nanoribbons with armchair and zigzag edges investigated with first principles calculations. Our results show that all the nanoribbons are semiconductors with suitable band gaps similar to silicon. And their band gaps decrease as widths of nanoribbons increase. We also find that the band gap is at the Γ point for all graphdiyne ribbons and it is at the X point for all graphyne ribbons. Of particular interest, the band gap of zigzag graphyne nanoribbons show a unique “step effect” as the width increases. This property is good for tuning of the energy band gap, as in a certain range of the ribbon width, the energy gap remains constant and in reality the edge cannot be as neat as that in a theoretic model.
Design and synthesis of superhydrophobic carbon nanofiber composite coatings for terahertz frequency shielding and attenuation
Authors: Das Arindam , Megaridis Constantine M. , Liu Lei , Wang Tao , Biswas Abhijit
Published: April 2011

We report design and synthesis of polymer-based large-area superhydrophobic carbon nanofiber (CNF) composite coatings for tunable electromagnetic interference shielding and attenuation in the terahertz (THz) frequency regime. Such coatings with different CNF/polymer weight ratios are characterized by a frequency domain THz spectroscopy system. A maximum THz shielding effectiveness of ∼32 dB was measured in the examined frequency range of 570–630 GHz. Coating attenuation level varied with CNF loading. Two-dimensional distributions of power attenuation at 600 GHz showed good spatial uniformity. The present composite coatings, in addition to their self-cleaning property, have high potential for advanced technology high-frequency applications.
Enhanced protein binding on femtosecond laser ablated poly(methyl methacrylate) surfaces
Authors: Ma Xiaodong , Huo Haibin , Wei Ming , Wang Lingling , Shen Mengyan , Barry Carol , Mead Joey
Published: April 2011

Poly(methyl methacrylate) (PMMA) substrates were ablated through a fast femtosecond (fs) laser scanning process to create patterns for enhanced protein binding. Typically, two patterns with lines and grids were produced and the protein binding was evaluated by studying the adsorption of fluorescein isothiocyanate (FITC)-labeled bovine serum albumin (BSA). It was found that the adsorption of FITC-BSA was increased up to tenfold on both patterns compared with the untreated PMMA surface, indicating the potential application of the fs laser ablated PMMA surfaces as protein assay substrates.
Mode shift of the voltage sensors in Shaker K+ channels is caused by energetic coupling to the pore domain
Authors: Haddad Georges A. , Blunck Rikard
Published: April 2011

The voltage sensors of voltage-gated ion channels undergo a conformational change upon depolarization of the membrane that leads to pore opening. This conformational change can be measured as gating currents and is thought to be transferred to the pore domain via an annealing of the covalent link between voltage sensor and pore (S4-S5 linker) and the C terminus of the pore domain (S6). Upon prolonged depolarizations, the voltage dependence of the charge movement shifts to more hyperpolarized potentials. This mode shift had been linked to C-type inactivation but has recently been suggested to be caused by a relaxation of the voltage sensor itself. In this study, we identified two ShakerIR mutations in the S4-S5 linker (I384N) and S6 (F484G) that, when mutated, completely uncouple voltage sensor movement from pore opening. Using these mutants, we show that the pore transfers energy onto the voltage sensor and that uncoupling the pore from the voltage sensor leads the voltage sensors to be activated at more negative potentials. This uncoupling also eliminates the mode shift occurring during prolonged depolarizations, indicating that the pore influences entry into the mode shift. Using voltage-clamp fluorometry, we identified that the slow conformational change of the S4 previously correlated with the mode shift disappears when uncoupling the pore. The effects can be explained by a mechanical load that is imposed upon the voltage sensors by the pore domain and allosterically modulates its conformation. Mode shift is caused by the stabilization of the open state but leads to a conformational change in the voltage sensor.
On maximal ranges of vector measures for subsets and purification of transition probabilities
Authors: Dai Peng , Feinberg Eugene
Published: April 2011

Consider a measurable space with an atomless finite vector measure. This measure defines a mapping of the

σ
\sigma

-field into a Euclidean space. According to the Lyapunov convexity theorem, the range of this mapping is a convex compactum. Similar ranges are also defined for measurable subsets of the space. Two subsets with the same vector measure may have different ranges. We investigate the question whether, among all the subsets having the same given vector measure, there always exists a set with the maximal range of the vector measure. The answer to this question is positive for two-dimensional vector measures and negative for higher dimensions. We use the existence of maximal ranges to strengthen the Dvoretzky-Wald-Wolfowitz purification theorem for the case of two measures.
Monomials as sums of powers: The real binary case
Authors: Boij Mats , Carlini Enrico , Geramita Anthony
Published: April 2011

We generalize an example, due to Sylvester, and prove that any monomial of degree

d
d

in

R

[

x
0

,

x
1

]

\mathbb {R}[x_0, x_1]

, which is not a power of a variable, cannot be written as a linear combination of fewer than

d
d

powers of linear forms.
Gauss images of hyperbolic cusps with convex polyhedral boundary
Authors: Fillastre François , Izmestiev Ivan
Published: April 2011

We prove that a 3–dimensional hyperbolic cusp with convex polyhedral boundary is uniquely determined by its Gauss image. Furthermore, any spherical metric on the torus with cone singularities of negative curvature and all closed contractible geodesics of length greater than2π2\piis the metric of the Gauss image of some convex polyhedral cusp. This result is an analog of the Rivin-Hodgson theorem characterizing compact convex hyperbolic polyhedra in terms of their Gauss images.

The proof uses a variational method. Namely, a cusp with a given Gauss image is identified with a critical point of a functional on the space of cusps with cone-type singularities along a family of half-lines. The functional is shown to be concave and to attain its maximum at an interior point of its domain. As a byproduct, we prove rigidity statements with respect to the Gauss image for cusps with or without cone-type singularities.

In a special case, our theorem is equivalent to the existence of a circle pattern on the torus, with prescribed combinatorics and intersection angles. This is the genus one case of a theorem by Thurston. In fact, our theorem extends Thurston’s theorem in the same way as Rivin-Hodgson’s theorem extends Andreev’s theorem on compact convex polyhedra with non-obtuse dihedral angles.

The functional used in the proof is the sum of a volume term and curvature term. We show that, in the situation of Thurston’s theorem, it is the potential for the combinatorial Ricci flow considered by Chow and Luo.

Our theorem represents the last special case of a general statement about isometric immersions of compact surfaces.
GM3 suppresses anchorage‐independent growth via Rho GDP dissociation inhibitor beta in melanoma B16 cells
Authors: Wang Pu , Xu Su , Wang Yinan , Wu Peixing , Zhang Jinghai , Sato Toshinori , Yamagata Sadako , Yamagata Tatsuya
Published: April 2011

Ly‐GDI, Rho GTPase dissociation inhibitor beta, was found to be expressed parallel to the GM3 level in mouse B16 cells whose GM3 contents were modified by B4galt6 sense, B4galt6 antisense cDNA, or St3galt5 siRNA transfection. Ly‐GDI expression was increased on GM3 addition to these cells and decreased with D‐PDMP treatment, a glucosylceramide synthesis inhibitor. Suppression of GM3 or Ly‐GDI by RNAi was concomitantly associated with an increase in anchorage‐independent growth in soft agar. These results clearly indicate that GM3 suppresses anchorage‐independent growth through Ly‐GDI. GM3 signals regulating Ly‐GDI expression was inhibited by LY294002, siRNA against Akt1 and Akt2 and rapamycin, showing that GM3 signals are transduced via the PI3K/Akt/mTOR pathway. Either siRNA towards Rictor or Raptor suppressed Ly‐GDI expression. The Raptor siRNA suppressed the effects of GM3 on Ly‐GDI expression and Akt phosphorylation at Thr308, suggesting GM3 signals to be transduced to mTOR‐Raptor and Akt‐Thr308, leading to Ly‐GDI stimulation. siRNA targeting Pdpk1 reduced Akt phosphorylation at Thr308 and rendered the cells insensitive to GM3 stimulation, indicating that Akt‐Thr308 plays a critical role in the pathway. The components aligned in this pathway showed similar effects on anchorage‐independent growth as GM3 and Ly‐GDI. Taken together, GM3 signals are transduced in B16 cells through PI3K, Pdpk1, AktThr308 and the mTOR/Raptor pathway, leading to enhanced expression of Ly‐GDI mRNA, which in turn suppresses anchorage‐independent growth in melanoma B16 cells. (Cancer Sci 2011; 102: 1476–1485)
Functional variant (−1304T>G) in the MKK4 promoter is associated with decreased risk of acute myeloid leukemia in a southern Chinese population
Authors: Jiang Lan , Zhou Ping , Sun Aining , Zheng Jian , Liu Bin , You Yonghe , Zhang Chun , Wu Depei , Zhou Yifeng
Published: April 2011

As a member of the MAPK kinase family, mitogen‐activated protein kinase kinase (MKK) 4 (NM_003010.2) is know to be involved in the regulation of apoptosis, inflammation, and tumorigenesis. Several polymorphisms have been identified in the promoter region of the MKK4 gene and we hypothesized that genetic variations in this region may alter gene expression, and thus cancer risk. In the present study, we genotyped two polymorphisms in the promoter of the MKK4 gene, namely −1304T>G (rs3826392) and −1044A>T (rs3809728), in 433 patients with AML and 600 controls, and assessed the association between those polymorphisms and the risk of AML. Compared with the −1304TT genotype, patients with the −1304TG genotype had a significantly decreased risk of AML (adjusted odds ratio (OR) 0.67; 95% confidence interval (CI) 0.51−0.87), with the risk decreased even further in those carrying −1304GG (OR 0.56; 95% CI 0.31–0.97). Additional experiments, which focused on reporter gene expression driven by MKK4 promoters, demonstrated that the presence of a −1304G allele led to greater transcriptional activity than the presence of a −1304T allele. However, no significant association was observed between the MKK4−1044A>T polymorphism and the risk of AML. These findings suggest that the functional −1304G>T variant may contribute to the risk of AML by enhancing the transcriptional activity of MKK4. Thus, this polymorphism may be a genetic modifier for the development of AML. (Cancer Sci 2011; 102: 1462–1468)
Roles of Pim‐3, a novel survival kinase, in tumorigenesis
Authors: Mukaida Naofumi , Wang Ying‐Ying , Li Ying‐Yi
Published: April 2011

Pim‐3 is a member of the Provirus integrating site Moloney murine leukemia virus (Pim) family, which belongs to the Ca2+/calmodulin‐dependent protein kinase (CaMK) group and exhibits serine/threonine kinase activity. Similar to other members of the Pim family (i.e. Pim‐1 and Pim‐2), Pim‐3 can prevent apoptosis and promote cell survival and protein translation, thereby enhancing cell proliferation of normal and malignant cells. Pim‐3 is expressed in vital organs, such as the heart, lung, and brain. However, minimal phenotypic changes in Pim‐3‐deficient mice suggest that Pim‐3 may be physiologically dispensable. Pim‐3 expression is enhanced in several cancer tissues, particularly those of endoderm‐derived organs, including the liver, pancreas, colon, and stomach. The development of hepatocellular carcinoma is accelerated in mice expressing the Pim‐3 gene selectively in the liver only when these mice are treated with a hepatocarcinogen, indicating that Pim‐3 can act as a promoter but not as an initiator. Moreover, inhibition of Pim‐3 expression can retard in vitro cell proliferation of hepatocellular, pancreatic, and colon carcinoma cell lines by promoting cell apoptosis. Furthermore, a Pim‐3 kinase inhibitor has been reported to inhibit cell proliferation in an in vivo xenograft model using a human pancreatic cancer cell line without inducing any major adverse effects. Thus, Pim‐3 kinase may be a candidate molecule for the development of molecular targeting drugs against cancer. (Cancer Sci 2011; 102: 1437–1442)