bluuebunny/crossref_metadata_2025 huggingface dataset:
Stress‐resilience capacity of pediatric oncologists: A Swedish nationwide and population‐based study of motivation, emotional distress, and overall life satisfaction
Authors: Stenmarker Margaretha , Palmérus Kerstin , Márky Ildikó
Published: December 2008

Background

Pediatric oncology is an area with heavy emotional distress. In balancing the daily challenges motivational factors might play a key role and could be examined by studying an individual's stress‐resilience capacity. This first nationwide population‐based study of 89 Swedish pediatric oncologists presents aspects of motivation related to experience and number of patients cared.

Procedure

In 2006, a cross‐sectional mail survey with questionnaires dealing with motivation, coping resources, life satisfaction and emotional distress was performed. The response rate in the target group was 88%.

Results

The physicians wanted to be well informed (98%) and updated at national (93%) and international (90%) level. Established routines gave them security managing different diagnoses (97%). Optimal pediatric oncology included several colleagues (98%) and a multi‐professional healthcare team (95%). Time pressure was a reality for every participant. Meeting seriously ill children was a way of being aware of essential issues of life (90%). More experienced pediatricians reported higher impact from motivational factors, past overall life satisfaction and a lower degree of somatization. The future overall life satisfaction was higher among physicians meeting more pediatric oncology patients. Between 8% and 45% of the variance in the stress‐resilience capacity of the whole group was explained by low levels of depression, future overall life satisfaction and aspects of motivation.

Conclusions

Pediatric oncologists continuously meet families in crisis. Knowledge of the physicians' stress‐resilience capacity is expected to be useful in improving the physician–patient relationship, retaining experienced physicians and recruiting new specialists in this medical field. Pediatr Blood Cancer 2009;52:503–509. © 2008 Wiley‐Liss, Inc.
Demographic data, natural history, and prognostic factors of idiopathic thrombocytopenic purpura in children: A multicentered study from Argentina
Authors: Donato Hugo , Picón Armando , Martinez Mónica , Rapetti María Cristina , Rosso Amadeo , Gomez Sergio , Rossi Nestor , Bacciedoni Viviana , Schvartzman Gabriel , Riccheri Cecilia , Costa Alejandra , Di Santo Juan
Published: December 2008

Background

Demographics, outcome, and management of idiopathic thrombocytopenic purpura (ITP) in children present differences between countries. Although several factors influence outcome, it is impossible to predict at diagnosis which patients will have acute or chronic disease. High rates of spontaneous remission in chronic ITP have been reported.

Procedure

Data concerning 1,683 patients with ITP diagnosed from 1981 to date are presented; outcome was evaluated in 1,418 children.

Results

Remarkable presenting features were an incidence peak in the first 2 years of age and male predominance in patients <24 months of age. Three age groups with different recovery rates (P < 0.001) were established (2–12 months: 89.8%; 1–8 years: 71.3%; 9–18 years: 49.0%). Platelet count <10 × 109/L and history of previous illness were associated with higher remission rates only in patients >12 months of age. The score developed by the NOPHO Group showed a predictive value of 83.9% for acute ITP. Spontaneous remission between 6 months and 11 years from diagnosis was achieved by 107 of 325 (32.9%) non‐splenectomized children with chronic ITP, and in 44.9% of them between 6 and 12 months from diagnosis.

Conclusions

Age and score were main prognostic factors. Infants <1 year of age are a special group with a brief course and very high recovery rate that are not influenced by other prognostic factors. Definition of groups based on age and scoring could be useful to establish differential management guidelines. The cut‐off value to define chronic ITP should be changed to 12 months. Pediatr Blood Cancer 2009;52:491–496. © 2008 Wiley‐Liss, Inc.
Informed choice in prenatal testing: a survey among obstetricians and gynaecologists in Europe and Asia
Authors: van den Heuvel Ananda , Chitty Lyn , Dormandy Elizabeth , Newson Ainsley , Deans Zuzana , Marteau Theresa M.
Published: December 2008

Purpose

To ascertain the extent to which the value obstetricians and gynaecologists attach to informed choice in the context of prenatal testing varies across countries.

Method

The values attached to informed choice and the perceived importance of test decisions reflecting the views of others considered significant to pregnant women were assessed and compared across obstetricians and gynaecologists in six countries: UK (n = 176), Netherlands (n = 331), Italy (n = 254), Greece (n = 116), China (n = 116) and India (n = 123).

Results

While respondents from the United Kingdom and the Netherlands almost unanimously believed prenatal testing should reflect a parental choice (94%), substantial minorities in Greece, India, and China and to a lesser extent Italy, believed testing should either reflect a family choice or no choice (11–41%). Respondents who attached a low value to the views of others attached greater value to parental choice. Multinomial logistic regression analysis confirmed the independent predictive value of a country and perceived importance of test decision reflecting the views of significant others.

Conclusion

While many obstetricians and gynaecologists favour prenatal testing reflecting a parental choice, the extent to which their values may affect the likelihood that informed choice is realised, may vary across countries. The impact of these findings on patient autonomy is raised. Copyright © 2008 John Wiley & Sons, Ltd.
Characterization of Plasma‐Polymerized Thiophene Thin Films and Nanoparticles Synthesized by a Double‐Discharge Technique
Authors: Goktas Hilal , Ince Fatma Gul
Published: December 2008

PTH nanoparticles and thin films were synthesized via a plasma polymerization technique using a double‐discharge system. This system has a fast filamentary discharge formed from the superposition of an ordinary low‐pressure dc glow discharge and a high‐current pulsed one. The samples were characterized by SEM, TEM, XPS, UV‐vis and FT‐IR spectroscopy. We found that superposing two discharges allows to control the morphology of the films. In the high‐temperature region, smooth and uniform thin films were produced, whereas gas‐phase polymerization resulted in films with grains of irregular shape. However, the films produced in the gas‐phase region exhibited highly thiophenic structures and could be dispersed in DCM, giving nanoparticles of 30 to 50 nm diameter.

magnified image
Alkyl‐Capped Silicon Nanocrystals Lack Cytotoxicity and have Enhanced Intracellular Accumulation in Malignant Cells via Cholesterol‐Dependent Endocytosis
Authors: Alsharif Naif H. , Berger Christine E. M. , Varanasi Satya S. , Chao Yimin , Horrocks Benjamin R. , Datta Harish K.
Published: December 2008

Nanocrystals of various inorganic materials are being considered for application in the life sciences as fluorescent labels and for such therapeutic applications as drug delivery or targeted cell destruction. The potential applications of the nanoparticles are critically compromised due to the well‐documented toxicity and lack of understanding about the mechanisms involved in the intracellular internalization. Here intracellular internalization and toxicity of alkyl‐capped silicon nanocrystals in human neoplastic and normal primary cells is reported. The capped nanocrystals lack cytotoxicity, and there is a marked difference in the rate and extent of intracellular accumulation of the nanoparticles between human cancerous and non‐cancerous primary cells, the rate and extent being higher in the malignant cells compared to normal human primary cells. The exposure of the cells to the alkyl‐capped nanocrystals demonstrates no evidence of in vitro cytotoxicity when assessed by cell morphology, apoptosis, and cell viability assays. The internalization of the nanocrystals by Hela and SW1353 cells is almost completely blocked by the pinocytosis inhibitors filipin, cytochalasin B, and actinomycin D. The internalization process is not associated with any surface change in the nanoparticles, as their luminescence spectrum is unaltered upon transport into the cytosol. The observed dramatic difference in the rate and extent of internalization of the nanocrystals between malignant and non‐malignant cells therefore offers potential application in the management of human neoplastic conditions.
Altering Arabidopsis Oilseed Composition by a Combined Antisense‐Hairpin RNAi Gene Suppression Approach
Authors: Nguyen Tam , Shanklin John
Published: December 2008

Antisense (AS) and hairpin (HP) RNA interference (RNAi) targeted gene suppression technologies have been used to modify seed oil composition. Larger numbers of AS transgenics have to be screened to achieve a targeted level of suppression compared to RNAi. We hypothesized combining AS with RNAi might result in enhanced gene suppression compared to either method individually. AS and HP‐RNAi were combined as hairpin antisense (HPAS) constructs containing ~125 bp sense and antisense portions of an untranslated region of the target gene separated by an intron containing an antisense copy of a portion of the target coding region. The Δ12‐desaturase FAD2, the ω3‐desaturase FAD3 and β‐ketoacyl‐ACP synthase (KAS) II were targeted in Arabidopsis to evaluate changes in oil composition with AS, HP and HPAS constructs driven by the phaseolin promoter. Modest but statistically significant enhancements in oilseed phenotypes were observed with HPAS relative to AS and HP‐RNAi. Phenotypes for HPAS suppression of FAD2 and FAD3 were indistinguishable from their strongest mutant alleles. Our data suggest that HPAS may be useful for: (1) achieving levels of suppression comparable to those of gene knockouts in a tissue specific manner. (2) Maximizing suppression of suboptimal RNAi constructs and (3) minimizing the screening of transgenics to achieve desired oilseed composition.
Preoperative Fasting Duration and Medication Instruction: Are We Improving?
Authors: Crenshaw Jeannette T. , Winslow Elizabeth H.
Published: December 2008

RESEARCH HAS SHOWN that preoperative fasting practices commonly are much longer than national guidelines, and medication instructions are not always given to patients before surgery. After implementation of an evidence‐based preoperative fasting policy and educational efforts for health care providers at one facility, a follow up project was conducted to determine whether these efforts had improved fasting practices.

THE PROJECT FINDINGS indicate that preoperative fasting in excess of safe minimum guidelines persists. Improvements were found in the percentage of patients receiving specific instructions about whether to take their routine medications on the morning of surgery. Continued efforts must be made to implement best practices for preoperative fasting. AORN J 88 (December 2008) 963–976. © AORN, Inc, 2008.
On a dual formulation for the growing sandpile problem
Authors: DUMONT S. , IGBIDA N.
Published: December 2008

In this paper, we are interested in the mathematical and numerical study of the Prigozhin model for a growing sandpile. Based on implicit Euler discretization in time, we give a simple improvement of theoretical and numerical analyses of the dual formulation for the problem. By using this model, we also give some application to the Monge–Kantorovich problem for optimal mass transportation.
Why did life emerge?
Authors: Annila Arto , Annila Erkki
Published: December 2008

Many mechanisms, functions and structures of life have been unraveled. However, the fundamental driving force that propelled chemical evolution and led to life has remained obscure. The second law of thermodynamics, written as an equation of motion, reveals that elemental abiotic matter evolves from the equilibrium via chemical reactions that couple to external energy towards complex biotic non-equilibrium systems. Each time a new mechanism of energy transduction emerges, e.g., by random variation in syntheses, evolution prompts by punctuation and settles to a stasis when the accessed free energy has been consumed. The evolutionary course towards an increasingly larger energy transduction system accumulates a diversity of energy transduction mechanisms, i.e. species. The rate of entropy increase is identified as the fitness criterion among the diverse mechanisms, which places the theory of evolution by natural selection on the fundamental thermodynamic principle with no demarcation line between inanimate and animate.
Circulation over a submarine canyon in the NW Mediterranean
Authors: Flexas M. M. , Boyer D. L. , Espino M. , Puigdefàbregas J. , Rubio A. , Company J. B.
Published: December 2008

The circulation in Blanes canyon, an interruption in the NW Mediterranean continental shelf north of Barcelona, was investigated. The study employs data from oceanographic surveys carried out in the summer and fall of 2003. Velocity data show that in the vicinity of the shelf break the flow is deflected along the canyon walls. A cyclonic mean flow can be seen over the canyon mouth owing to vortex stretching of fluid parcels advected across the shelf break. Field observations are in qualitative agreement with fundamental fluid dynamic considerations based on potential vorticity conservation and friction effects at lateral boundaries. Evidence is given that upwelling is found near the shelf break inside the canyon in the two field experiments. This upwelling extends vertically from the seasonal thermocline (at about 100 m) to the shelf‐slope front (at about 200 m). There is no evidence that upwelled water can reach the continental shelf.
Altitude effect in UV radiation during the Evaluation of the Effects of Elevation and Aerosols on the Ultraviolet Radiation 2002 (VELETA‐2002) field campaign
Authors: Sola Y. , Lorente J. , Campmany E. , de Cabo X. , Bech J. , Redaño A. , Martínez‐Lozano J. A. , Utrillas M. P. , Alados‐Arboledas L. , Olmo F. J. , Díaz J. P. , Expósito F. J. , Cachorro V. , Sorribas M. , Labajo A. , Vilaplana J. M. , Silva A. M. , Badosa J.
Published: December 2008

The Evaluation of the Effects of Elevation and Aerosols on the Ultraviolet Radiation 2002 (VELETA‐2002) field campaign was designed to study the influence of aerosols and altitude on solar UV irradiance. The altitude effect (AE) was evaluated for UV irradiance under cloudless conditions by taking spectral and broadband measurements in SE Spain in the summer of 2002 at three nearby sites located at different heights (680 m, 2200 m, and 3398 m). A spectral radiative transfer model (Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART)) was also applied, mainly to evaluate the tropospheric ozone impact on AE. Results are related to the optical properties and air mass origin of the aerosols as determined by back‐trajectory analysis. During the 1‐week observing period of the campaign, there were two main synoptic situations with different air masses (polar maritime and tropical continental air mass associated with a Saharan dust event). The AE showed a high dependency on wavelength, solar zenith angle, and aerosols, although the growth of the mixing layer during the day also caused substantial AE variability. Saharan dust caused an increase in AE, especially in the UVB region and in the erythemal irradiance. In the UVA (320–400 nm) band the AE ranged 6–8% km−1 at noon, while for the UVB (280–320 nm) band it reached 7–11% km−1. The AE for erythemally weighted irradiance ranged from 11 to 14% km−1 between the lowest and highest stations when it was calculated from spectral measurements.
Long‐term evolution of the cold point tropical tropopause: Simulation results and attribution analysis
Authors: Austin John , Reichler Thomas J.
Published: December 2008

The height, pressure, and temperature of the cold point tropical tropopause are examined in three 140 year simulations of a coupled chemistry climate model. Tropopause height increases approximately steadily in the simulations at a mean rate of 63 ± 3 m/decade (2σ confidence interval). The pressure trend changes near the year 2000 from −1.03 ± 0.30 hPa/decade in the past to −0.55 ± 0.06 hPa/decade for the future. The trend in tropopause temperature changes even more markedly from −0.13 ± 0.07 K/decade in the past to +0.254 ± 0.014 K/decade in the future. The tropopause data were fit using regression by terms representing total column ozone, tropical mean sea surface temperatures, and tropical mass upwelling. Tropopause height and pressure closely follow the upwelling term, whereas tropopause temperature is primarily related to sea surface temperature and ozone. The change in tropopause temperature trend near the year 2000 is related to the change in the sign of the ozone trend with the sea surface temperature having an increased role after 2040. A conceptual model is used to estimate tropopause changes. The results confirm the regression analysis in showing the importance of upper tropospheric warming (connected with sea surface temperature) and stratospheric cooling (connected with CO2 and O3). In the past, global warming and ozone depletion have opposite effects on the tropopause temperature, which decreases slightly. For the future simulation, global warming and ozone recovery reinforce which increases the tropopause temperature. In particular, future tropopause change is found not to be an indicator of climate change alone.
Toward improving the reliability of hydrologic prediction: Model structure uncertainty and its quantification using ensemble‐based genetic programming framework
Authors: Parasuraman Kamban , Elshorbagy Amin
Published: December 2008

Uncertainty analysis is starting to be widely acknowledged as an integral part of hydrological modeling. The conventional treatment of uncertainty analysis in hydrologic modeling is to assume a deterministic model structure, and treat its associated parameters as imperfectly known, thereby neglecting the uncertainty associated with the model structure. In this paper, a modeling framework that can explicitly account for the effect of model structure uncertainty has been proposed. The modeling framework is based on initially generating different realizations of the original data set using a non‐parametric bootstrap method, and then exploiting the ability of the self‐organizing algorithms, namely genetic programming, to evolve their own model structure for each of the resampled data sets. The resulting ensemble of models is then used to quantify the uncertainty associated with the model structure. The performance of the proposed modeling framework is analyzed with regards to its ability in characterizing the evapotranspiration process at the Southwest Sand Storage facility, located near Ft. McMurray, Alberta. Eddy‐covariance‐measured actual evapotranspiration is modeled as a function of net radiation, air temperature, ground temperature, relative humidity, and wind speed. Investigating the relation between model complexity, prediction accuracy, and uncertainty, two sets of experiments were carried out by varying the level of mathematical operators that can be used to define the predictand‐predictor relationship. While the first set uses just the additive operators, the second set uses both the additive and the multiplicative operators to define the predictand‐predictor relationship. The results suggest that increasing the model complexity may lead to better prediction accuracy but at an expense of increasing uncertainty. Compared to the model parameter uncertainty, the relative contribution of model structure uncertainty to the predictive uncertainty of a model is shown to be more important. Furthermore, the study advocates that the search to find the optimal model could be replaced by the quest to unearth possible models for characterizing hydrological processes.
Building conceptual models of field‐scale uranium reactive transport in a dynamic vadose zone‐aquifer‐river system
Authors: Yabusaki Steven B. , Fang Yilin , Waichler Scott R.
Published: December 2008

Subsurface simulation is used to build, test, and couple conceptual process models to better understand the persistence of uranium concentrations above federal drinking water standards in a 0.4 km by 1.0 km groundwater plume beneath the 300 Area of the U.S. Department of Energy's Hanford Site in eastern Washington State. At this location, the unconfined aquifer and the variably saturated lower vadose zone sediments are subject to significant variations in water levels driven by diurnal, weekly, and seasonal fluctuations in the Columbia River stage. In the near‐river aquifer, uranium‐contaminated sediments in the highly transmissive Hanford formation are subject to high groundwater velocities, daily flow reversals, and exposure to river water. One‐ and two‐dimensional simulations of variably saturated flow and reactive transport based on laboratory‐derived models of uranium sorption are used to assess the representation of uranium transport processes in the vadose zone‐aquifer‐river system. The simulations show that the various frequencies of river stage fluctuation are capable of driving significant inland transport above the average water table, which is in contrast to the net groundwater flow to the river. Inclusion of a rate‐limited uranium mass transfer process model is notably more important to the timescales of the river stage‐driven groundwater flow than for vadose zone flow driven by natural recharge. Spatially and temporally variable solution chemistry from the dynamic exchange of river water and groundwater in the unconfined aquifer is shown to significantly alter uranium mobility as represented by a multicomponent uranium surface complexation model.
Pliocene Role in Assessing Future Climate Impacts
Authors: Robinson Marci M. , Dowsett Harry J. , Chandler Mark A.
Published: December 2008

Future warming projected by the Intergovernmental Panel on Climate Change (IPCC) has the potential to affect every person on Earth. Extreme weather events, rising sea level, and migrating ecosystems and resources may result in socioeconomic stresses. Although we can plan and prepare for what is expected, the most dangerous aspect of our changing climate is the uncertainty in climate sensitivity.

To reduce the uncertainties of climate change, paleoclimatologists are focusing on a possible yet imperfect analog to a future warmer climate.
High‐resolution surveys along the hot spot–affected Gálapagos Spreading Center: 3. Black smoker discoveries and the implications for geological controls on hydrothermal activity
Authors: Haymon Rachel M. , White Scott M. , Baker Edward T. , Anderson Peter G. , Macdonald Ken C. , Resing Joseph A.
Published: December 2008

To explore effects of hot spots on mid‐ocean ridge hydrothermal systems, we conducted nested sonar, hydrothermal plume, and near‐bottom photographic surveys along the portion of the Galápagos Spreading Center (GSC) influenced by the Galápagos hot spot, from longitude 95°–89.5°W. We report the first active high‐temperature black smokers to be found on the GSC, at longitudes 94°4.5′W and 91°56.2′–54.3′W; describe two areas of recently inactive smokers, at longitudes 91°23.4′–23.7′W and 91°13.8′W; and document an older inactive site, at longitude 90°33.4′W. All imaged vents issue either from dike‐induced fissures along linear axial volcanic ridges and collapses or from a caldera. Magmatic control of hydrothermal systems also is revealed by spatial clustering of plumes within the topographically elevated middles of volcanic ridge segments with inferred centralized melt supply. In searched areas, smokers are more typical than diffuse flow vents, but total GSC plume incidence is half of that expected from the spreading rate. Why? Dike‐fed fissures provide permeable pathways for efficient hydrothermal extraction of magmatic heat, but cones without calderas do not. Among many point‐source cones surveyed, only the two with calderas had detectable plumes. Possibly, dominance of point‐source over linear‐source melt delivery on the GSC decreases plume incidence. Also, similar maturities of observed vents and their host lava flows indicate that hydrothermally active volcanic segments along the western GSC are contemporaneously in a waning phase of volcanic‐hydrothermal activity. Perhaps ridge/hot spot interaction produces melt pulses that drive near‐synchronous volcanic‐hydrothermal activity on the volcanic segments spanning the hot spot. During active periods, hydrothermally active dike‐fed fissures and calderas may be more abundant than we currently observe.
Mantle convection with longest‐wavelength thermal heterogeneity in a 3‐D spherical model: Degree one or two?
Authors: Yoshida Masaki
Published: December 2008

The formation of longest‐wavelength mantle convection in the sluggish‐lid regime is investigated using a three‐dimensional spherical model. The bottom Rayleigh number is fixed at 107. Considering temperature‐dependent rheology, degree‐one dominant thermal convection occurs for both purely basal heating and mixed (i.e., basal and internal) heating modes. For the purely basal heating mode, degree‐one convection occurs when the viscosity contrast due to temperature‐dependent rheology is 103–104 in both Boussinesq and extended‐Boussinesq fluids. However, with extended‐Boussinesq fluid, degree‐one convection may only occur in the basal heating mode: In the mixed heating mode, degree‐one convection shifts to one with high‐degree modes, presumably because of enhanced viscous dissipation in the highly viscous lid over up/downwelling plumes. The geophysically relevant degree‐two convection with sheet‐like downwellings is not observed in this study. The inclusion of visco‐plastic rheology in the top part of the mantle breaks down degree‐one convection.
Low‐frequency acoustic‐gravity waves from coseismic vertical deformation associated with the 2004 Sumatra‐Andaman earthquake (Mw = 9.2)
Authors: Mikumo Takeshi , Shibutani Takuo , Le Pichon Alexis , Garces Milton , Fee David , Tsuyuki Takahiro , Watada Shingo , Morii Wataru
Published: December 2008

Atmospheric pressure perturbations from the 2004 Sumatra‐Andaman earthquake (Mw = 9.2) were observed by sensitive microbarographs at several global stations. Among these observations, very low‐frequency acoustic‐gravity waves (∼1.4–2.8 mHz) with a group velocity around 300–314 m/s and amplitudes ranging between ∼1 and 12 Pa can be clearly identified through data processing at four stations on the Japanese Islands and also at four International Monitoring System (IMS) stations around the Indian Ocean. Assuming several seismic source parameters for this great thrust earthquake, we produce synthetic barograms using a realistic thermal structure in the atmosphere up to an altitude of 220 km. For this modeling, we incorporate the source dimensions in different zones, the expanding velocity of the source region, the vertical displacements of uplift and subsidence, and their time constants. Combinations of these source parameters provide synthetic waveforms consistent with the general features of the observed low‐frequency records. The results clearly indicate that the recorded waves may have been generated by large‐scale coseismic uplift and subsidence of the sea bottom and associated swelling and depression of the sea surface over the source region extending for 1500 km. The uplift in the south‐central zone of the Andaman‐Nicobar regions may be substantially larger than in the other zones. The time constant of the coseimic vertical deformation is found to be in the range of 1.0–1.5 min, which may correspond to the time elapsed shortly before the generation of tsunami waves.
Ice stream basal conditions from block‐wise surface data inversion and simple regression models of ice stream flow: Application to Bindschadler Ice Stream
Authors: Sergienko O. V. , Bindschadler R. A. , Vornberger P. L. , MacAyeal D. R.
Published: December 2008

Widespread basal conditions controlling ice stream flows are still beyond the scope of direct observation, thus knowledge of their magnitudes and variabilities comes from inversion of surface measurements: ice velocities, surface elevations, and thicknesses. We present a new approach to implement a widely accepted inverse method on regular (10 × 10 km) blocks, smaller than the whole domain, to enhance the spatial resolution of calculated basal conditions. Inverted basal friction coefficients and calculated shear stress have sharp transitions and large variations in small areas. Overall, the obtained basal shear stress is very small in regions of fast flowing ice. The results of the inversion, along with the surface variables, are used to construct two simple regression models of Bindschadler Ice Stream (former Ice Stream D) that reproduce 96% of observed velocity variations. While highly idealized, these regression models are sufficiently informative to be considered as parameterizations for ice stream flow in large‐scale ice sheet models which lack the spatial and temporal resolution necessary to simulate ice stream dynamics in detail.
Overweight and Obesity: Prediction by Silhouettes in Young Adults
Authors: Muñoz‐Cachón M.J. , Salces Itziar , Arroyo Marta , Ansotegui Laura , Rocandio A.M. , Rebato Esther
Published: December 2008

The present study analyzes the prevalence of overweight/obesity in a sample of young adults from the University of the Basque Country (Spain), and tests the efficiency of the silhouettes to predict overweight/obesity. This cross‐sectional study was conducted in a sample of volunteer university students from the University of the Basque Country (356 men and 745 women, age: 18–33 years), who came to the Physical Anthropology laboratory where a standardized questionnaire was administered and anthropometric measurements were taken by a well‐trained anthropometrist. Height and weight were obtained. BMI was calculated as weight/height2 (kg/m2) and it was used as a reference method. Using a questionnaire, based on the standard figural stimuli, subjects were asked to choose the silhouette which was closest to his/her usual appearance (current body size). The accuracy of the Williamson et al.'s silhouettes as an overweight‐obesity indicator was analyzed by gender‐specific receiver operating curve (ROC). The cutoff figure to distinguish between nonoverweight and overweight‐obese individuals corresponded to number 7 in men and 6 in women. These cutoff values matched optimal sensitivity and specificity, with few nonoverweight subjects selecting silhouettes bigger than 7 in the case of men or 6 for women. In conclusion, the figural stimuli allows the identification of populations at overweight/obesity risk with the simple use of silhouettes, at least in this rank of age, where the overweight and obesity are yet little frequent.
Computer‐aided tissue engineering: application to biomimetic modelling and design of tissue scaffolds
Authors: Sun Wei , Starly Binil , Darling Andrew , Gomez Connie
Published: December 2008

Computer‐aided tissue engineering (CATE) enables many novel approaches in modelling, design and fabrication of complex tissue substitutes with enhanced functionality and improved cell–matrix interactions. Central to CATE is its bio‐tissue informatics model that represents tissue biological, biomechanical and biochemical information that serves as a central repository to interface design, simulation and tissue fabrication. The present paper discusses the application of a CATE approach to the biomimetic design of bone tissue scaffold. A general CATE‐based process for biomimetic modelling, anatomic reconstruction, computer‐assisted‐design of tissue scaffold, quantitative‐computed‐tomography characterization, finite element analysis and freeform extruding deposition for fabrication of scaffold is presented.
RNA interference of metastasis‐associated gene 1 inhibits metastasis of B16F10 melanoma cells in a C57BL/6 mouse model
Authors: Qian Haili , Yu Jing , Li Yunfeng , Wang Haijuan , Song Chongwen , Zhang Xueyan , Liang Xiao , Fu Ming , Lin Chen
Published: December 2008

Background information. MTA1 (metastasis‐associated gene 1) has been reported to be overexpressed in cancers with high potential to metastasize. Studies of the molecular mechanisms revealed that MTA1 plays an important role in the process of metastasis of many types of cancer. However, the role of MTA1 in melanoma development is unclear.

Results. We have investigated the therapeutic value of MTA1 in the B16F10 melanoma cell line with the C57BL/6 mouse model. Studies in vitro showed that MTA1 promoted the metastatic ability of B16F10 cancer cells. MTA1 down‐regulation by RNA interference greatly reversed the malignant phenotypes of cancer cells. Immunohistochemical staining of MTA1 in human melanoma samples confirmed the up‐regulation of MTA1 in the process of carcinogenesis. Studies in vivo confirmed down‐regulation of MTA1 suppressed the growth and experimental metastasis of B16F10 melanoma cells.

Conclusions. MTA1 plays an important role in melanoma development and metastasis. It has a promising potential as a target for in cancer gene therapy or chemotherapy.
Arf GAPs as regulators of the actin cytoskeleton
Authors: Randazzo Paul A. , Inoue Hiroki , Bharti Sanita
Published: December 2008

The Arf (ADP‐ribosylation factor) GAPs (GTPase‐activating proteins) are a family of proteins with a common catalytic domain that induces hydrolysis of GTP bound to Arf GTP‐binding proteins. At least three groups of multidomain Arf GAPs affect the actin cytoskeleton and cellular activities, such as migration and movement, that depend on the cytoskeleton. One role of the Arf GAPs is to regulate membrane remodelling that accompanies actin polymerization. Regulation of membrane remodelling is mediated in part by the regulation of Arf proteins. However, Arf GAPs also regulate actin independently of effects on membranes or Arf. These functions include acting as upstream regulators of Rho family proteins and providing a scaffold for Rho effectors and exchange factors. With multiple functional elements, the Arf GAPs could integrate signals and biochemical activities that result in co‐ordinated changes in actin and membranes necessary for a wide range of cellular functions.
Role of Auditory Cortex in Noise- and Drug-Induced Tinnitus
Authors: Eggermont Jos J.
Published: December 2008

Purpose

To elucidate the role of auditory cortex in tinnitus.

Method

Neurophysiological findings in cat auditory cortex following noise trauma or the application of salicylate and quinine, all expected to induce tinnitus, were reviewed. Those findings were interpreted in the context of what is expected from studies in humans, specifically in the brains of people with tinnitus.

Results

Tinnitus is an auditory percept to which several central structures in the auditory system may contribute. Because the central auditory system has both feed-forward connections and feedback connections, it can be described as a set of nested loops. Once these loops become activated in a pathological fashion, as they may be in tinnitus, it becomes hard to assign importance to each contributing structure. Strongly interconnected networks, that is, neural assemblies, may be determining the quality of the tinnitus percept.

Conclusion

It is unlikely that tinnitus is the expression of a set of independently firing neurons, and more likely that it is the result of a pathologically increased synchrony between sets of neurons. There is clear evidence for this from both evoked potentials and from neuron-pair synchrony measures.
Exposure to Disability and Hearing Loss Narratives in Undergraduate Audiology Curriculum
Authors: Berg Abbey L. , Canellas Maryrose , Salbod Stephen , Velayo Richard
Published: December 2008

Purpose

To determine whether exposure to disability and hearing loss narratives increased undergraduate communication sciences and disorders (CSD) students' affective responses to scenarios of individuals with hearing impairment.

Method

Thirty-five CSD undergraduates responded to 8 scenarios (K. English, L. L. Mendel, T. Rojeski, & J. Hornak, 1999). Sixteen students completed a course in audiologic rehabilitation with no exposure to disability and hearing loss narratives; 19 students completed the same course with exposure. Two audiologists, independent and blind to group status, rated the 35 student responses for affective and technical content.

Results

Students exposed to the narratives incorporated more affective elements into their technical responses than students not exposed.

Conclusions

Narratives appear to be effective in increasing affective elements in students' technical/informational responses and may have a place and be of value in undergraduate CSD curriculum.
Gap Detection Methods for Assessing Salicylate-Induced Tinnitus and Hyperacusis in Rats
Authors: Turner Jeremy G. , Parrish Jennifer
Published: December 2008

Purpose

A variety of options for behavioral assessment of tinnitus in laboratory animals are available to researchers today. These options are briefly reviewed, followed by data suggesting that gap detection procedures might be used to efficiently measure acute, salicylate-induced tinnitus and possibly hyperacusis in rats.

Method

Fischer Brown Norway rats (
n
= 10) were given intraperitoneal injections of 350 mg/kg sodium salicylate on 2 consecutive days, and the effects on gap detection were observed across 9 different frequency bands. Pretest, posttest, and washout data were collected. An additional 4 rats were each given 4 different doses of sodium salicylate (0, 150, 250, and 300 mg/kg), and gap detection and prepulse inhibition were measured.

Results

Significant gap detection deficits were observed from pre- to posttest that were consistent with tinnitus. Consistent gap detection deficits were found using broadband noise backgrounds, while significant improvements in responding to frequency-specific test bands were found. Similar effects were repeated in the dose response portion of the study.

Conclusions

Gap detection procedures efficiently measured salicylate-induced changes in behavior that were consistent with the presence of tinnitus. In addition, the reliable, stronger responses at many frequencies after salicylate injections suggest the possibility of measuring a hyperacusis-like phenomenon using these methods.
Fluctuations of the partition function in the generalized random energy model with external field
Authors: Bovier Anton , Klimovsky Anton
Published: December 2008

We study Derrida’s generalized random energy model (GREM) in the presence of uniform external field. We compute the fluctuations of the ground state and of the partition function in the thermodynamic limit for all admissible values of parameters. We find that the fluctuations are described by a hierarchical structure which is obtained by a certain coarse graining of the initial hierarchical structure of the GREM with external field. We provide an explicit formula for the free energy of the model. We also derive some large deviation results providing an expression for the free energy in a class of models with Gaussian Hamiltonians and external field. Finally, we prove that the coarse-grained parts of the system emerging in the thermodynamic limit tend to have a certain optimal magnetization, as prescribed by the strength of the external field and by parameters of the GREM.
Nonlinear study on the terahertz free electron laser amplifier with elliptical waveguide
Authors: Wang Minghong , Liu Pukun , Xue Qianzhong , Dong Ruixin
Published: December 2008

The use of an elliptical waveguide and a planar wiggler with parabolically tapered pole pieces as the terahertz free electron laser (FEL) amplifier model is proposed. A set of self-consistent differential equations for the FEL amplifier is derived by using nonlinear theory, and the characteristics of this amplifier are numerically analyzed. Our numerical simulations are conducted to the 1000GHz amplifier with an electron beam energy of 1.74MeV. The results indicate that the peak power of 180kW and frequency bandwidth of 13.5GHz can be obtained.
Obliquely propagating ion acoustic solitary waves and double layers in a magnetized dusty plasma with anisotropic ion pressure
Authors: Chatterjee Prasanta , Saha Taraknath , Ryu Chang-Mo
Published: December 2008

Obliquely propagating dust ion acoustic solitary waves and double layers in an external magnetic field is studied by using Sagdeev’s pseudo-potential technique. Anisotropic ion pressure is considered, which is defined by applying the Chew–Goldberger–Low theory. The Sagdeev pseudo-potential is derived considering the Poisson equation instead of the charge neutrality condition so that the length scales of the solitary waves and double layers may be shorter than the Debye length. The ranges of parameters for which solitary waves and double layers can exist are studied in detail.
Simulating oligomerization at experimental concentrations and long timescales: A Markov state model approach
Authors: Kelley Nicholas W. , Vishal V. , Krafft Grant A. , Pande Vijay S.
Published: December 2008

Here, we present a novel computational approach for describing the formation of oligomeric assemblies at experimental concentrations and timescales. We propose an extension to the Markovian state model approach, where one includes low concentration oligomeric states analytically. This allows simulation on long timescales (seconds timescale) and at arbitrarily low concentrations (e.g., the micromolar concentrations found in experiments), while still using an all-atom model for protein and solvent. As a proof of concept, we apply this methodology to the oligomerization of an Aβ peptide fragment (Aβ21–43). Aβ oligomers are now widely recognized as the primary neurotoxic structures leading to Alzheimer’s disease. Our computational methods predict that Aβ trimers form at micromolar concentrations in 10ms, while tetramers form 1000 times more slowly. Moreover, the simulation results predict specific intermonomer contacts present in the oligomer ensemble as well as putative structures for small molecular weight oligomers. Based on our simulations and statistical models, we propose a novel mutation to stabilize the trimeric form of Aβ in an experimentally verifiable manner.
Composition dependence of field induced anisotropy in ferromagnetic (Co,Fe)89Zr7B4 and (Co,Fe)88Zr7B4Cu1 amorphous and nanocrystalline ribbons
Authors: Ohodnicki P. R. , Long J. , Laughlin D. E. , McHenry M. E. , Keylin V. , Huth J.
Published: December 2008

The composition dependence of field induced anisotropy KU of field annealed soft ferromagnetic (Co1−xFex)89Zr7B4 and (Co1−xFex)88Zr7B4Cu1 amorphous and amorphous/nanocrystalline “nanocomposite” melt spun ribbons is investigated. With the exception of the highest Co-containing alloys (x<∼0.10), the observations are discussed in terms of a superposition of directional pair ordering of Fe,Co atoms and an additional contribution presumably due to the presence of Zr and B in both the field crystallized and field annealed amorphous ribbons. The highest Co-containing alloys (x<∼0.10) contain multiple nanocrystalline phases (bcc, fcc, and hcp) for which a peak in KU is observed (KU∼2000–2500 J/m3). In this framework, asymmetry in the compositional dependence of KU resulting in larger values for Co-rich alloys relative to Fe-rich alloys for both the field crystallized and field annealed amorphous alloys is explained in terms of a strong dependence of the Curie temperature of the amorphous phase on the Co content.
Direct mapping of recoil in the ion-pair dissociation of molecular oxygen by a femtosecond depletion method
Authors: Baklanov Alexey V. , Janssen Liesbeth M. C. , Parker David H. , Poisson Lionel , Soep Benoit , Mestdagh Jean-Michel , Gobert Olivier
Published: December 2008

Time-resolved dynamics of the photodissociation of molecular oxygen, O2, via the Σu−3 ion-pair state have been studied with femtosecond time resolution using a pump-probe scheme in combination with velocity map imaging of the resulting O+ and O− ions. The fourth harmonic of a femtosecond titanium-sapphire (Ti:sapphire) laser (λ≈205nm) was found to cause three-photon pumping of O2 to a level at 18.1eV. The parallel character of the observed O+ and O− images allowed us to conclude that dissociation takes place on the Σu−3 ion-pair state. The 815nm fundamental of the Ti:sapphire laser used as probe was found to cause two-photon electron photodetachment starting from the O2 ion-pair state, giving rise to (O(P3)+O+(S4)) products. This was revealed by the observed depletion of the yield of the O− anion and the appearance of a new O+ cation signal with a kinetic energy Etransl(O+) dependent on the time delay between the pump and probe lasers. This time-delay dependence of the dissociation dynamics on the ion-pair state has also been simulated, and the experimental and simulated results coincide very well over the experimental delay-time interval from about 130fsto20ps where two- or one-photon photodetachment takes place, corresponding to a change in the R(O+,O−) interatomic distance from 12 to about 900Å. This is one of the first implementations of a depletion scheme in femtosecond pump-probe experiments which could prove to be quite versatile and applicable to many femtosecond time-scale experiments.
Dimensional scaling treatment of stability of simple diatomic molecules induced by superintense, high-frequency laser fields
Authors: Wei Qi , Kais Sabre , Herschbach Dudley
Published: December 2008

We present results obtained using dimensional scaling with high-frequency Floquet theory to evaluate the stability of gas phase simple diatomic molecules in superintense laser fields. The large-D limit provides a simple model that captures the main physics of the problem, which imposes electron localization along the polarization direction of the laser field. This localization markedly reduces the ionization probability and can enhance chemical bonding when the laser strength becomes sufficiently strong. We find that energy and structure calculations at the large-dimensional limit (D→∞) for stabilities of H2+, H2, and He2 in superintense laser fields are much simpler than at D=3, yet yield similar results to those found from demanding ab initio calculations. We also use the large-D model to predict the stability of H2− and the field strength needed to bind the “extra” electron to the H2 molecule.
Adsorption of self-avoiding tethered membranes: A Monte Carlo simulation study
Authors: Popova Hristina , Milchev Andrey
Published: December 2008

Adsorption of self-avoiding tethered membranes of hexagonal orientation on a solid impenetrable plane is studied by means of Monte Carlo computer simulations of a coarse-grained continuum model, varying the membrane linear size L and the strength ϵ of the short-range attractive wall potential. A second-order adsorption transition is found to take place at a critical strength of the adsorption potential ϵc, as predicted earlier for binding manifolds in the so-called strong fluctuating regime. By means of finite-size scaling analysis for membranes of size 5≤L≤30, containing 61≤N≤2611 monomers, we find that the critical crossover exponent for adsorption ϕ≈0.60±0.01. Thus the fraction m of adsorbed segments at ϵc is found to scale as m∝Nϕ−1=N−0.4. The membrane thickness λmin decreases with growing strength ϵ of the adhesive potential as λmin∝|ϵ/ϵc−1|−ψ, where ψ≈0.58±0.02. The monomer density profiles of adsorbed membranes decay exponentially with the distance z from the substrate ρ(z)∝exp[−(z/ξ)], where the correlation length ξ∝|ϵ/ϵc−1|−ψ̃ with ψ̃≈0.70±0.01. We also investigate the kinetics of adsorption of a polymerized membrane in the regime of strong adsorption and find that the order parameter variation with elapsed time during the adsorption process is given by a power law m(t)∝tω, where ω≈1.0, regardless of the strength of the adsorbing potential ϵ⪢ϵc. The characteristic time for complete adsorption in this regime scales as τads∝L2. Regarding the strength ϵ of the substrate potential, τads is found to diminish linearly as the respective equilibrium value of the order parameter increases. A simple analytic model yields also τads∝L2 while suggesting that the process of adsorption cannot be identified by simple “unrolling.”