bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Thermophysical Methods for Oxide/Silicate Glasses
Authors: Chromčíková Mária , Liška Marek
Published: October 2015

An brief overview of the selected thermo-physical measurements realized in the VILA laboratories for the glass industry and for the fundamental research of glass is presented. Among the routine measurements realized for the glass industry the thermodilatometry for measuring the glass transition temperature, and linear thermal expansion coefficients of glass and metastable glassforming melt are described in detail. The fact that the glass transition temperature is not a single valued physical quantity is stressed in connection with the measurement time temperature schedule. The probably most important quantity related to the glass production technology is the viscosity. Its measurement in the range extending ten orders of magnitude is described. The combination of the falling ball method, the rotation viscosimetry and the thermomechanical analysis is needed to cover the above viscosity range. Among the methods used in the fundamental research of glass structure and properties the study of structural relaxation is overviewed. Here the own method of combined viscous flow and structure relaxation TMA measurement is described in detail.
Low Temperature Internal Gettering of Bulk Defects in Silicon Photovoltaic Materials
Authors: Al-Amin Mohammad , Murphy J.D.
Published: October 2015

Multicrystalline silicon (mc-Si) substrates are widely used for photovoltaic cells. The minority carrier lifetime in mc-Si is affected by recombination associated with metallic impurities in many forms, such as point-like defects, precipitates and bound to or precipitated at structural defects such as dislocations. We have studied the effect of low temperature annealing on the lifetime and bulk iron concentration in as-received mc-Si wafers from different locations within a block. Lifetime measurements are made using a temporary iodine-ethanol surface passivation technique to minimize the occurrence of bulk hydrogenation which often occurs from dielectric films. In good wafers from the middle of the block the lifetime is reduced by annealing at 400 °C and 500 °C in a way which does not correlate with changes in bulk iron concentration. Lifetime improvements occur in relatively poor samples from the top and bottom of the block annealed at 300 °C, and also in samples from the bottom annealed at 400 °C. The improvement in bottom wafers correlates with iron loss from the bulk. Our work shows that under some conditions the lifetime in relatively poor as-grown wafers can be improved by low temperature internal gettering.
Vacancy Species Produced by Rapid Thermal Annealing of Silicon Wafers
Authors: Voronkov Vladimir V. , Falster Robert
Published: October 2015

Rapid thermal annealing (RTA) of Czochralski silicon wafers at around 1260°C installs a depth profile of some vacancy species. Subsequent oxygen precipitation in such wafers is vacancy-assisted. The data on RTA-installed vacancy profiles - and the corresponding precipitate density profiles - suggest that there is a slow-diffusing vacancy species (Vs) along with two fast-diffusing species: a Watkins vacancy (Vw) manifested in irradiation experiments and fast vacancy (Vf) responsible for the high-T vacancy contribution into self-diffusion. The Vs species are lost during cooling stage of RTA, and the loss seems to occur by conversion of Vs into Vf followed by a quick out-diffusion of Vf. A model based on this scenario provides a good fit to the reported profiles of oxide precipitate density in RTA wafers for different values of TRTA and different cooling rates.
Orientation Dependency of Dislocation Generation in Si Growth Process
Authors: Jiptner Karolin , Miyamura Yoshiji , Gao Bing , Harada Hirofumi , Kakimoto Koichi , Sekiguchi Takashi
Published: October 2015

In an attempt to understand how and where dislocations are introduced into Si ingots by temperature gradients, bulk dislocation-free FZ crystals are exposed to temperature gradients similar to those in Bridgman Si crystal growth. This heat treatment introduces dislocations, which were analyzed using X-ray topography (XRT) and Scanning InfraRed Polariscopy (SIRP). Hereby, the orientation dependency is taken into account and ingots in (001) and (111) growth orientation are evaluated in this work. It can be found that the dislocation generation takes place at similar regions of the crystal and is independent of orientation, however, their propagation and multiplication differs. This leads to an overall different shape of the dislocation network. Especially intriguing are the long slip lines in the (111)-crystal, which cannot be found in the (001)-crystal. This suggests a different magnitude of slip propagation depending on the sample orientation. This effect should be explained by a different activation of slip systems and is discussed in the paper.
Metastable Defects in Proton Implanted and Annealed Silicon
Authors: Jelinek Moriz , Laven Johannes G. , Ganagona Naveen , Job Reinhart , Schustereder Werner , Schulze Hans Joachim , Rommel Mathias , Frey Lothar
Published: October 2015

Two metastable defects with energy levels at Ec-0.28eV and Ec-0.37eV, which previously have been reported in proton implanted- and in proton implanted and annealed crystalline silicon are discussed. Recent results on the peculiar behavior of these defects upon periodical application of two different bias conditions during DLTS measurement are reviewed. Two specifically designed DLTS measurement sequences are proposed in order to further reveal the defects transformation rates and respective activation energies.
The Efficiency of Hydrogen-Doping as a Function of Implantation Temperature
Authors: Jelinek Moriz , Laven Johannes G. , Ganagona Naveen , Schustereder Werner , Schulze Hans Joachim , Rommel Mathias , Frey Lothar
Published: October 2015

– For a conventional proton implantation doping process applied to crystalline silicon comprising proton implantation and subsequent furnace annealing the effect of the substrate temperature set during implantation is examined for temperatures between 50 °C and 200 °C. The formation efficiency of the hydrogen related donors in the maximum of the related doping profiles is shown to linearly increase with the implantation temperature. Regarding the dose rate, a reverted effect is found. The appearing effects are explained by considering the evolution of the initial implantation damage towards a vacancy related precursor species of the hydrogen related donor. Additional information about the implantation temperature dependent defect distribution is gained from Fourier-DLTS results.
Mössbauer Spectroscopy on Fe Impurities in Si Materials
Authors: Yoshida Yutaka , Ino Yuji , Tanaka Kiyotaka
Published: October 2015

Based on a series of Mössbauer spectroscopic investigations on Fe impurities in p-type and n-type Si materials, we propose a new model for Fe impurities in Si matrix, consisting not only of interstitial Fe, but also substitutional Fe atoms with different charge states. Mössbauer spectroscopy enables us to observe directly these components which transform each other by changing external conditions such as under light illumination, under external voltage, and also under external stress. This means that not only interstitial Fe impurities, but also substitutional Fe impurities appear to be a source for producing “electrically active Fe impurities” in Si materials.
Internal Gettering of Copper for Microelectronic Applications
Authors: Kissinger Gudrun , Kot Dawid , Schubert Markus Andreas , Sattler Andreas , Müller Timo
Published: October 2015

The results of this work have shown that for microelectronic applications, gettering at dislocations is less important and oxygen precipitates are the main getter sink for Cu. Sufficient gettering of Cu in samples contaminated with low Cu concentration requires a higher density and larger oxygen precipitates compared to samples contaminated with high Cu concentration. It is demonstrated that the getter efficiency depends on the contamination level of the samples and getter test with low contamination level must be applied for microelectronic applications. Furthermore, a getter test for 3D chip stack technologies was developed. It was shown that although the wafers are thinned to a thickness of 50 μm their getter efficiency seems to be higher than for wafers of the original thickness. This is assumed to be due to the higher Cu concentration in the thinner wafers which can be gettered easier. It is also demonstrated that BMDs can getter Cu impurities even if the temperature does not exceed 300 °C. The getter efficiency tends to be higher if the samples are stored under day light and not in the dark.
Detection and Prevention of Palladium Contamination in Silicon Devices
Authors: Polignano Maria Luisa , Mica Isabella , Brambilla Agostino , Brambilla Claudio , Brambilla Simona , Ceresoli Monica , Codegoni Davide , Farini Laura , Somaini Francesco
Published: October 2015

In this work we report the results of a set of experiments carried out to assess the ability of recombination lifetime measurements for the detection of palladium contamination in silicon. Palladium is found to be a very effective recombination center, so recombination lifetime measurements are a very sensitive method to detect palladium in silicon. The surface segregation of palladium was monitored by the reduction of its recombination activity in the silicon volume. The palladium segregation at the wafer surface was checked by selective etching, and by Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX) analysis.After validating recombination lifetime measurements for palladium detection, we use these measurements to define suitable approaches to the prevention of palladium contamination of silicon devices. The efficiency of a diffusion barrier layer (silicon nitride) and of decontamination by wet cleaning are tested.
Search for Effective Sites of Proximity Gettering Induced by Ion Implantation in Si Wafers with First Principles Calculation
Authors: Shirasawa Sho , Sueoka Koji
Published: October 2015

Fe, Ni and Cu atoms diffuse very quickly in Si and are the main targets for metal gettering. W, Hf, and Mo atoms, for example, which diffuse very slowly in Si have also recently become gettering targets in addition to these metals. Therefore, proximity gettering techniques by using ion implantation are being considered. Not only implanted elements but intrinsic point defects exist and form several complexes after the heat treatment for Si crystal recovery. This research systematically investigated the binding energy of twelve important metals (Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Hf, Ta, and W) with implanted dopants (B, C, P, and As) and their complexes with intrinsic point defects (vacancies (Vs) and self-interstitials (Is)) by using first principles calculation. These data should be useful in the design of proximity gettering in LSI manufacturing processes.
Structure, Electronic Properties and Annealing Behavior of Di-Interstitial-Oxygen Center in Silicon
Authors: Markevich Vladimir P. , Peaker Anthony R. , Hamilton Bruce , Gusakov Vasilii E. , Lastovskii Stanislav B. , Murin Leonid I. , Ganagona Naveengoud , Monakhov E.V. , Svensson Bengt Gunnar
Published: October 2015

It is argued in this work that a DLTS signal associated with hole emission from a radiation-induced defect with an energy level at Ev + 0.09 eV is related to a complex of silicon di-interstitial with an oxygen atom (I2O). This signal has been observed in the DLTS spectra of p-type Si:O samples irradiated with either 4-6 MeV electrons or alpha particles. Isochronal and isothermal annealing studies of the samples have shown that the defect responsible for the DLTS signal from the Ev + 0.09 eV level disappears upon heat-treatments in the temperature range 75-100 °C and its formation and annealing behavior is similar to that of a center giving rise to the infrared absorption band at 936 cm-1 previously assigned to a local vibrational mode (LVM) due to the I2O complex.
Possible configurations of the I2O complex have been found by ab-initio modeling and analyzed. Formation and binding energies, energy levels and LVMs for different configurations have been determined. It has been found that the minimum energy configuration of the I2O complex consists of the compact I2 to which a divalent interstitial oxygen atom is attached. Calculated values of the strongest LVM (ν = 971 см-1 ) and position of the donor level {Ev + (0.11-0.13) eV} for the minimum energy configuration are very close to those assigned to the I2O defect in the infrared absorption and DLTS experiments.
Growth of Czochralski Silicon Crystals Having Ultralow Carbon Concentrations
Authors: Nagai Yuta , Kashima Kazuhiko , Nakagawa Satoko , Higasa Mitsuo
Published: October 2015

Reducing the carbon concentration in Czochralski (CZ) silicon crystals is crucial in order to improve the properties of high-power devices, such as on-resistance and carrier lifetime. To achieve carbon concentration reduction, it is necessary to reduce carbon monoxide (CO) contamination from the CZ furnace graphite components and to remove the carbon impurities originating from the starting material. In this study, suppressing the chemical reaction between silicon monoxide (SiO) and the graphite heater effectively reduced the CO contamination rate. Furthermore, we attempted to promote CO evaporation during the CZ process in order to remove carbon impurities from the melt. Increasing the Ar gas flow velocity above the melt surface was found to be effective in increasing the CO evaporation rate during both the melting and growth processes. The CO evaporation rate during the melting process of 8-inch CZ silicon was calculated as being of the order of 10-2 μg/s. Owing to the effects of the CO evaporation, 8-inch CZ silicon crystals with carbon concentrations lower than 2.0 × 1014 atoms/cm3 at a solidified fraction of 0.85 were grown.
50 cm Size Seed Cast Si Ingot Growth and its Characterization
Authors: Sekiguchi Takashi , Miyamura Yoshiji , Harada Hirofumi , Jiptner Karolin , Chen Jun , Prakash Ronit R. , Nakano Satoshi , Gao Bing , Kakimoto Koichi
Published: October 2015

We have proposed single seed cast Si growth and developed a furnace for 50 cm square ingots. By optimizing growth parameters, improving gas condition, coating, the quality of mono Si ingot has improved. Namely, dislocation density, the concentrations of substitutional carbon and interstitial oxygen have been significantly reduced. The conversion efficiency of cast Si solar cells has become comparable with those of CZ Si wafers.
Statistical Consideration of Grain Growth Mechanism of Multicrystalline Si by One-Directional Solidification Technique
Authors: Sekiguchi Takashi , Prakash Ronit R. , Jiptner Karolin , Luo Xian Jia , Chen Jun , Miyamura Yoshiji , Harada Hirofumi
Published: October 2015

The grain evolution of multicrystalline Si was studied using the ingot grown from microcrystalline template. The grain shape evolution and width increase are not monotonic but may have 3 stages. On the other hand, the grain boundary (GB) analysis suggests that there exit 2 reactions, namely random GB annihilation at the initial stage and Σ3 generation and annihilation at the steady state.
Radiation Damage in 4H-SiC and its Effect on Power Device Characteristics
Authors: Hazdra Pavel , Popelka Stanislav , Záhlava Vít , Vobecký Jan
Published: October 2015

The effect of neutron, electron and ion irradiation on electrical characteristics of unipolar 1700V SiC power devices (JBS diodes, JFETs and MESFETs) was investigated. DLTS investigation showed that above mentioned projectiles introduce similar deep acceptor levels (electron traps) in the SiC bandgap which compensate nitrogen shallow donors and cause majority carrier (electron) removal. The key degradation effect occurring in irradiated devices is the increase of the ON-state resistance which is caused by compensation of the low doped n-type epilayer and simultaneous lowering of electron mobility. In the case of SiC power switches (JFET, MOSFET), these effects are accompanied by the shift of the threshold voltage. Radiation defects introduced in SiC power devices is unstable and some defects anneal out already at operation temperatures (below 175°C). However, this does not have significant effect on device characteristics.
Ab Initio Study of MgSe Self-Interstitial (Mgi and Sei)
Authors: Igumbor Emmanuel , Obodo Kingsley , Meyer Water E.
Published: October 2015

We present detailed calculations of formation and thermodynamics transition state energies of Mgi and Sei interstitial defects in MgSe using generalized gradient approximation (GGA) and local density approximation (LDA) functional in the frame work of density functional theory (DFT). For both LDA and GGA the formation energies of Mgi and Sei are relatively low in all the configurations. The most stable Se interstitial was the tetrahedral (T) configuration having lower formation energy than the decagonal (D) configuration. The Mgi and Sei defect introduced transition state levels that had either donor or acceptor levels within the band gap. Sei acts as a donor or an acceptor and creates levels that were either deep or shallow depending on the configuration. Sei exhibit negative-U properties and show charge states metastability in the D configuration. Mgi acts as only shallow donor (+2/ + 1) in both T and D configurations, in addition we pointed out the role of Mgias electrically activating donor.
Comparative Investigations of the Surface Damage of Monocrystalline Silicon Wafers by Scanning Infrared Reflection Examination and Raman Spectroscopy
Authors: Möller Hans Joachim , Würzner Sindy , Buchwald Rajko , Herms Martin , Wagner Matthias
Published: October 2015

Mechanical preparation of mono-and multicrystalline silicon wafers by sawing, lapping, or grinding damages the surface. Depending on the mechanical impact of the treatment different degrees of damage structures occur. It is necessary for further processing of wafers to have damage free and contactless methods to characterize structures such as changes of the lattice structure by phase transformations or plastic deformations, and microcracks below the surface. In this paper we present results of investigations on the sub-surface damage by two contactless optical methods: Scanning infrared reflection polarimetry with SIREX and Raman spectroscopy. The investigations were carried out on silicon wafers sawn with the multi-wire technique using diamond coated wires. The sub-surface damage mainly consists of microcracks of different length, which penetrate several micrometers into the bulk. The results were compared with confocal microscopy and scanning electron microscopy analyses of the same damage structures.
Comparative Spatially Resolved Characterization of a Czochralski-Grown Silicon Crystal by Different Laser-Based Imaging Techniques
Authors: Herms Martin , Wagner Matthias , Molchanov Alexander , Rommel Mathias , Zschorsch Markus , Würzner Sindy
Published: October 2015

The axial distribution of electrical and optical properties of a 4 inch Czochralski-grown silicon single crystal were analyzed by different methods that can be applied in the scanning mode. These methods were tested with respect to the suitability to reveal growth striations. The residual stress was visualized by SIRIS (Scanning Infrared Stress Inspection System) and SIREX (Scanning Infrared Stress Explorer), the electrical resistivity by LPS (Lateral Photovoltage Scanning) and SRP (Spreading Resistance Profiling), and the lifetime of the minority charge carriers by MDP (Microwave Detected Photoconductivity) mapping. The concentration of interstitial oxygen (Oi) across the growth striations was determined by FTIR (Fourier Transform Infrared) spectroscopy. We demonstrate for the first time on the micrometer scale that the Oi scan is very well-correlated with the profile of Δσ (difference of the in-plane principal stress components). The stress field is tensile oriented in growth direction, i. e. perpendicularly to the growth striations. The stress-concentration coefficient has been estimated to be in the order of 10-13 Pa cm-3 what does agree well with previous XRD results.
Imaging Defect Luminescence of 4H-SiC by Ultraviolet-Photoluminescence
Authors: Berwian Patrick , Kaminzky Daniel , Rosshirt Katharina , Kallinger Birgit , Friedrich Jochen , Oppel Steffen , Schneider Adrian , Schütz Michael
Published: October 2015

A new tool for characterizing extended defects in Silicon Carbide (SiC) based on photoluminescence imaging is presented. In contrast to other techniques like Defect Selective Etching (DSE) or X-ray topography this technique is both fast and non-destructive. It is shown that several defect types, especially those relevant for the performance of electronic devices on SiC (i.e. Stacking Faults and Basal Plane Dislocations) can be investigated. The tool is therefore usable in research and development for a quick feedback on process related defect generation as well as in a production environment for quality control.
Valence-Mending Passivation of Si(100) Surface: Principle, Practice and Application
Authors: Tao Meng
Published: October 2015

Surface states have hindered and degraded many semiconductor devices since the Bardeen era. Surface states originate from dangling bonds on the surface. This paper discusses a generic solution to surface states, i.e. valence-mending passivation. For the Si (100) surface, a single atomic layer of valence-mending sulfur, selenium or tellurium can terminate ~99% of the dangling bonds, while group VII fluorine or chlorine can terminate the remaining 1%. Valence-mending passivation of Si (100) has been demonstrated using CVD, MBE and solution passivation. The keys to valence-mending passivation include an atomically-clean Si (100) surface for passivation and precisely one monolayer of valence-mending atoms on the surface. The passivated surface exhibits unprecedented properties. Electronically the Schottky barrier height between various metals and valence-mended Si (100) now follows more closely the Mott-Schottky theory. With metals of extreme workfunctions, new records for low and high Schottky barriers are created on Si (100). The highest barrier so far is 1.14 eV, i.e. a larger-than-bandgap barrier, and the lowest barrier is below 0.08 eV and potentially negative. Chemically silicidation between metal and valence-mended Si (100) is suppressed up to 500 °C, and the thermally-stable record Schottky barriers enable their applications in nanoelectronic, optoelectronic and photovoltaic devices. Another application is transition metal dichalcogenides. Valence-mended Si (100) is an ideal starting surface for growth of dichalcogenides, as it provides only van der Waals bonding to the dichalcogenide.
Stable, Extrinsic, Field Effect Passivation for Back Contact Silicon Solar Cells
Authors: Bonilla Ruy S. , Collett Katherine , Rands Lucy , Martins George , Lobo Richard , Wilshaw Peter R.
Published: October 2015

A new technique is described by which ionic species can be rapidly transported into oxide films, and once there provide effective and stable field effect passivation to silicon surfaces. Field effect passivation in thermally grown oxide films has been achieved by embedding potassium ions using a combined drift and diffusion mechanism at high temperature. This process has been shown to be over 10 times faster than a pure diffusion process. The resulting passivation stable for periods exceeding 600 days, with lifetimes reaching 1.4 ms, equivalent to a surface recombination velocity (SRV) ≤ 5.7 cm/s, on 1 Ωcm, n-type, FZ-Si.
Investigation of Parasitic Edge Recombination in High-Lifetime Oxidized n-Si
Authors: Bonilla Ruy S. , Martins George , Wilshaw Peter R.
Published: October 2015

An investigation of the parasitic surface recombination mechanisms in high-lifetime oxidized n-Si is presented. An approximate analytical expression describing recombination at the edge of square shaped specimens is derived. This shows that edge recombination can have a significant effect on the effective lifetime as measured using the transient photo-conductance technique and that for well passivated high quality material edge recombination can be the dominant mechanism in reducing the effective lifetime below the intrinsic level. For 3 x 3 cm2 pieces of silicon measured using a Sinton photo-conductance lifetime instrument, it is shown that recombination at the edge of the sample results in an additional component to the measured lifetime of around 16 ms at an injection level of 1015 cm-3. When this effect is taken into account measurements of 1 Ωcm FZ-Si show that a SRV as low as 1.5 cm/s is possible when the surface is passivated using a corona charge concentration of +2.2 x 1012 q/cm2 deposited on a 100 nm oxide layer.
A Novel Single Gene Deletion (−αMAL3.5) Giving Rise to Silent α Thalassemia Carrier Removing the Entire HBA2 Gene Observed in Two Chinese Patients with Hb H Disease: Case Report of Two Probands
Authors: Abdul Hamid Faidatul Syazlin , Ahmad Rahimah , Saleem Mohamed , Aziz Nur Aisyah , Omar Syahira Lazira , Mohamad Arif Siti Hida Hajira , Sathar Jameela , Zakaria Zubaidah
Published: October 2015

We report a novel deletion at the HBA2 presented with Hb H disease in two Malaysian- Chinese patients. The two unrelated probands were diagnosed with Hb H disease in a primary hematological screening for thalassemia. Results from routine molecular analysis with gap-polymerase chain reaction (PCR) method revealed a genotype asynchrony with the observed clinical presentation. Subsequent DNA analysis using a battery of molecular methods such as gap-PCR, multiplex ligation dependent probe amplification, DNA sequencing, confirmed the presence of a novel deletion in both the index cases removing the entire α2 globin gene. We have designated the deletion as (−αMAL3.5). Hematological indices and clinical findings suggest that the deletion has an α+ phenotype. The molecular process of this deletion is the result from misalignment and unequal crossover event between the duplicated homologous Y-boxes within the α globin gene cluster. Uncharacterized deletions, single nucleotide polymorphism and other nucleotide indels at the primer binding sites may impede the optimum condition for its annealing and extension and therefore may invalidate the gap-PCR obscuring the real genotype.
P.G.R. de Villiers Dedication – A tribute
Authors: Van Eck Ernest
Published: October 2015

No abstract available.
Atypical proliferative endometrioid tumor of ovary
Authors: Jetley S , Khetrapal S , Ahmad A , Jairajpuri ZS
Published: October 2015

Borderline ovarian tumors represent 10-20% of epithelial ovarian neoplasms that typically have an excellent prognosis. Both the oncological behavior of this group of tumors and also the diagnostic histological criteria are intermediate between the specific criteria of benign and malignant. They usually occur in the third to fourth decade of women's lives and are limited to the ovary in 80% of cases. Atypical proliferative or borderline ovarian tumors constitute a group of epithelial tumors with an excellent prognosis due to the low aggressiveness, microscopic examination is mandatory in order to establish an accurate histological diagnosis in all cases of borderline ovarian tumors and to differentiate from well differentiated adenocarcinoma. We report a case of a 45 year old female who presented with irregular bleeding per vaginum and underwent hysterectomy with bilateral salpingo-oophorectomy. Atypical proliferative endometrioid tumor of the left ovary was an incidental finding, which is a very rare occurrence.
The effectiveness of acetic acid wash protocol and the interpretation patterns of blood contaminated cervical cytology ThinPrep®specimens
Authors: Frisch Nora K. , Ahmed Yasin , Sethi Seema , Neill Daniel , Kalinicheva Tatyana , Shidham Vinod
Published: October 2015

Background:

ThinPrep®(TP) cervical cytology, as a liquid-based method, has many benefits but also a relatively high unsatisfactory rate due to debris/lubricant contamination and the presence of blood. These contaminants clog the TP filter and prevent the deposition of adequate diagnostic cells on the slide. An acetic acid wash (AAW) protocol is often used to lyse red blood cells, before preparing the TP slides.

Design:

From 23,291 TP cervical cytology specimens over a 4-month period, 2739 underwent AAW protocol due to initial unsatisfactory smear (UNS) with scant cellularity due to blood or being grossly bloody. Randomly selected 2739 cervical cytology specimens which did not undergo AAW from the same time period formed the control (non-AAW) group. Cytopathologic interpretations of AAW and non-AAW groups were compared using the Chi-square test.

Results:

About 94.2% of the 2739 cases which underwent AAW were subsequently satisfactory for evaluation with interpretations of atypical squamous cells of undetermined significance (ASCUS) 4.9% (135), low-grade squamous intraepithelial lesions (LSIL) 3.7% (102), and high-grade squamous intraepithelial lesions (HSIL) 1% (28). From the 2739 control cases, 96.3% were satisfactory with ASCUS 5.5% (151), LSIL 5.1% (139), and HSIL 0.7% (19). The prevalence of ASCUS interpretations was similar (P= 0.33). Although there were 32% more HSIL interpretations in the AAW group (28 in AAW vs. 19 in non-AAW), the difference was statistically insignificant (P= 0.18). AAW category; however, had significantly fewer LSIL interpretations (P= 0.02). The percentage of UNS cases remained higher in the AAW group with statistical significance (P< 0.01).

Conclusions:

While AAW had a significantly higher percent of UNS interpretations, the protocol was effective in rescuing 94.2% of specimens which otherwise may have been reported unsatisfactory. This improved patient care by avoiding a repeat test. The prevalence of ASCUS and HSIL interpretations between AAW and non-AAW groups were comparable. Though not statistically significant, HSIL interpretations were relatively higher in the AAW group. LSIL interpretations showed lower prevalence in AAW group.
Engagement, Exploration, Empowerment
Authors: Stoffel Virginia (Ginny)
Published: October 2015

Engagement, exploration, and empowerment are significant practice strategies used by occupational therapy practitioners as a means of getting to know what matters to clients and how to facilitate their participation in everyday life. Applied to the American Occupational Therapy Association (AOTA) as an organization, professional engagement, exploration of new service contexts, and empowerment of members to take an active role in shaping the profession's future are examined. This address, given at the 2015 AOTA Annual Convention & Expo, looks to the future in terms of engaging greater numbers of members; participating in Vision 2025, a strategic planning initiative that will be unveiled at the 2016 AOTA Annual Conference & Expo; and empowering members to achieve excellence in occupational therapy.
Implications of carbon monoxide bias for methane lifetime and atmospheric composition in chemistry climate models
Authors: Strode S. A. , Duncan B. N. , Yegorova E. A. , Kouatchou J. , Ziemke J. R. , Douglass A. R.
Published: October 2015

Abstract. A low bias in carbon monoxide (CO) at northern high and mid-latitudes is a common feature of chemistry climate models (CCMs) that may indicate or contribute to a high bias in simulated OH and corresponding low bias in methane lifetime. We use simulations with CO tagged by source type to investigate the sensitivity of the CO bias to CO emissions, transport, global mean OH, and the hemispheric asymmetry of OH. We also investigate how each of these possible contributors to the CO bias affects the methane lifetime. We find that the use of specified meteorology alters the distribution of CO compared to a free-running CCM simulation, improving the comparison with surface observations in summer. Our results also show that reducing the hemispheric asymmetry of OH improves the agreement of simulated CO with observations. We use simulations with parameterized OH to quantify the impact of known model biases on simulated OH. Removing biases in ozone and water vapor as well as reducing Northern Hemisphere NOx does not remove the hemispheric asymmetry in OH, but it reduces global mean OH by 18 %, bringing the simulated methane lifetime into agreement with observation-based estimates.
An analytical system for the measurement of stable hydrogen isotopes in ambient volatile organic compounds
Authors: Meisehen T. , Bühler F. , Koppmann R. , Krebsbach M.
Published: October 2015

Abstract. Stable isotope measurements in atmospheric volatile organic compounds (VOCs) are an excellent tool to analyse chemical and dynamical processes in the atmosphere. While up to now isotope studies of VOCs in ambient air have mainly focussed on carbon isotopes, we herein present a new measurement system to investigate hydrogen isotope ratios in atmospheric VOCs. This system, consisting of a gas chromatography pyrolysis isotope ratio mass spectrometer (GC-P-IRMS) and a pre-concentration system, was thoroughly characterised using a VOC test mixture. A precision of better than 9 ‰ (in δ 2H) is achieved for n-pentane, 2-methyl-1,3-butadiene (isoprene), n-heptane, 4-methyl-pentane-2-one (4-methyl-2-pentanone), methylbenzene (toluene), n-octane, ethylbenzene, m/p-xylene and 1,2,4-trimethylbenzene. A comparison with independent measurements via elemental analysis shows an accuracy of better than 9 ‰ for n-pentane, n-heptane, 4-methyl-2-pentanone, toluene and n-octane. Above a minimum required pre-concentrated compound mass the obtained δ 2H values are constant within the standard deviations. In addition, a remarkable influence of the pyrolysis process on the isotope ratios is found and discussed. Reliable measurements are only possible if the ceramic tube used for the pyrolysis is sufficiently conditioned, i.e. the inner surface is covered with a carbon layer. It is essential to verify this conditioning regularly and to renew it if required. Furthermore, influences of a necessary H3+ correction and the pyrolysis temperature on the isotope ratios are discussed. Finally, the applicability to measure hydrogen isotope ratios in VOCs at ambient levels is demonstrated with measurements of outside air on 5 different days in February and March 2015. The measured hydrogen isotope ratios range from −136 to −105 ‰ forn-pentane, from −86 to −63 ‰ for toluene, from −39 to −15 ‰ for ethylbenzene, from −99 to −68 ‰ for m/p-xylene and from −45 to −34 ‰ for o-xylene.
Frequency and intensity of palaeofloods at the interface of Atlantic and Mediterranean climate domains
Authors: Wilhelm B. , Vogel H. , Crouzet C. , Etienne D. , Anselmetti F. S.
Published: October 2015

Abstract. The long-term response of the flood activity to both Atlantic and Mediterranean climatic influences was explored by studying a lake sequence (Lake Foréant) of the Western European Alps. High-resolution sedimentological and geochemical analysis revealed 171 turbidites, 168 of which result from past flood events over the last millennium. The deposit thickness was used as a proxy of intensity of past floods. Because the Foréant palaeoflood record is in agreement with the documented variability of historical floods resulting from local and mesoscale convective events, it is assumed to highlight changes in flood frequency and intensity related to such events typical of both climatic influences. Comparing the Foréant record with other Atlantic-influenced and Mediterranean-influenced regional flood records highlights a common feature in all flood patterns that is a higher flood frequency during the cold period of the Little Ice Age (LIA). In contrast, high-intensity flood events are apparent during both, the cold LIA and the warm Medieval Climate Anomaly (MCA). However, there is a tendency towards higher frequencies of these events during the warm MCA. The MCA extremes could mean that under the global warming scenario, we might see an increase in intensity (not in frequency). However, the flood frequency and intensity in course of 20th century warming trend did not change significantly. Uncertainties lie in the interpretation of the lack of 20th century extremes (transition or stable?) and the different climate forcing factors (greenhouse gases vs. solar/volcanic eruptions).
Impacts of grid resolution on surface energy fluxes simulated with an integrated surface-groundwater flow model
Authors: Shrestha P. , Sulis M. , Simmer C. , Kollet S.
Published: October 2015

Abstract. The hydrological component of the Terrestrial Systems Modeling Platform (TerrSysMP), which includes integrated surface-groundwater flow, was used to investigate the grid resolution dependence of simulated soil moisture, soil temperature, and surface energy fluxes over a sub-catchment of the Rur, Germany. The investigation was motivated by the recent developments of new earth system models, which include 3-D physically based groundwater models for the coupling of land–atmosphere interaction and subsurface hydrodynamics. Our findings suggest that for grid resolutions between 100 and 1000 m, the non-local controls of soil moisture are highly grid resolution dependent. Local vegetation, however, strongly modulates the scaling behavior, especially for surface fluxes and soil temperature, which depends on the radiative transfer property of the canopy. This study also shows that for grid resolutions above a few 100 m, the variation of spatial and temporal patterns of sensible and latent heat fluxes may significantly affect the resulting atmospheric mesoscale circulation and boundary layer evolution in coupled runs.
Technical Note: The impact of spatial scale in bias correction of climate model output for hydrologic impact studies
Authors: Maurer E. P. , Ficklin D. L. , Wang W.
Published: October 2015

Abstract. Statistical downscaling is a commonly used technique for translating large-scale climate model output to a scale appropriate for assessing impacts. To ensure downscaled meteorology can be used in climate impact studies, downscaling must correct biases in the large-scale signal. A simple and generally effective method for accommodating systematic biases in large-scale model output is quantile mapping, which has been applied to many variables and shown to reduce biases on average, even in the presence of non-stationarity. Quantile mapping bias correction has been applied at spatial scales ranging from areas of hundreds of kilometers to individual points, such as weather station locations. Since water resources and other models used to simulate climate impacts are sensitive to biases in input meteorology, there is a motivation to apply bias correction at a scale fine enough that the downscaled data closely resembles historically observed data, though past work has identified undesirable consequences to applying quantile mapping at too fine a scale. This study explores the role of the spatial scale at which the quantile-mapping bias correction is applied, in the context of estimating high and low daily streamflows across the Western United States. We vary the spatial scale at which quantile mapping bias correction is performed from 2° (∼ 200 km) to 1/8° (∼ 12 km) within a statistical downscaling procedure, and use the downscaled daily precipitation and temperature to drive a hydrology model. We find that little additional benefit is obtained, and some skill is degraded, when using quantile mapping at scales finer than approximately 0.5° (∼ 50 km). This can provide guidance to those applying the quantile mapping bias correction method for hydrologic impacts analysis.
Analysis of soil moisture condition under different land uses in the arid region of Horqin sandy land, northern China
Authors: Niu C. Y. , Musa A. , Liu Y.
Published: October 2015

Abstract. Land use plays an important role in controlling spatial and temporal variations of soil moisture by influencing infiltration rates, runoff and evapotranspiration, which is important to crop growth and vegetation restoration in semiarid environments, such as Horqin sandy land in north China. However, few studies have been conducted comparing differences of dynamics of soil water conditions and the responses of soil to infiltration under different land use types in semiarid area. Five different land use types were selected to analyze soil moisture variations in relation to land use patterns during the growing season of 2 years. Results showed that soil moisture condition was affected by different land uses in semi-arid sandy soils. The higher soil moisture content among different land uses was exhibited by the grassland, followed by cropland, poplar land, inter-dunes and shrub land. The temporal variations of soil moisture in different land uses were not always consistent with the rainfall due to the dry sequence. Moreover, soil water at the surface, in the root zone and at the deep soil layer indicated statistical differences for different types of land cover. Meanwhile, temporal variations of soil moisture profile changed with precipitation. However, in the deep soil layer, there was a clear lag in response to precipitation. In addition, seasonal variations of profile soil moisture were classified into two types: increasing and waving types. And the stable soil water layer was at 80–120 cm. Furthermore, the infiltration depth exhibited a positive correlation with precipitation under all land uses. This study provided an insight into the implications for land and agricultural water management in this area.
Nietzsche's Actuality: Boscovich and the Extremities of Becoming
Authors: Tones Matthew , Mandalios John
Published: October 2015

The problem of persistence and emergence endowed with the limits of “actuality” is examined in the context of Nietzsche's appropriation of both Heraclitus and Boscovich to forge a natural philosophy of becoming. The physics of Boscovich allowed a systematic refurbishment of Heraclitean notions of becoming over being while Heraclitus's tensive dynamic of generation surpassed and overcame the limits of Anaximander's indeterminate. Nietzsche's early investigations bear overt signs of a formative philosophical outlook that seeks to marry the infinite and the sensible in a fashion consistent with his mature concept of becoming.
The association between filial piety and loneliness among Chinese older adults in the greater Chicago area
Authors: Dong XinQi , Zhang Manrui , Chang E-Shien
Published: October 2015

Background: Loneliness is an important health indicator for psychological well-being. This study aims to examine the association between filial piety and loneliness among Chinese older adults in the U.S.Methods: Data were drawn from the PINE study, a population-based study of 3,159 Chinese older adults aged 60 and above in the greater Chicago area. Severity of loneliness was the dependent variable. Independent variables were the expectation and perceived receipt of filial piety, examined in six domains. Negative Binomial Regression analyses were conducted.Results: Lower levels of perceived filial piety receipt were associated with greater severity of loneliness (Ratio of Expected Severity: 0.92, 0.91-0.94) after adjusting for socio-demographics and medical co-morbidities. Expectation of filial piety was not associated with severity of loneliness.Conclusion: Our findings indicate higher perceived receipt of filial piety may protect older adults from loneliness. Our study suggests that cultural sensitivity need to be considered in the detection and intervention of loneliness.
Exacerbation of Migraines Following Robotic Surgery for Endometrial Carcinoma
Authors: Geisler John P , Manahan Kelly J
Published: October 2015

Objective: Robotic hysterectomies are becoming increasingly common in the United States. Although benefits exist, risks are also present. The purpose of this study was to see what percentage of women with migraine headaches had a post-operative exacerbation.Study design: Records were examined for the diagnosis of migraine headaches as well as post-operative diagnosis of a headache. Records were also examined for age, estimated blood loss, total skin to skin operative time and body mass index.Results: Surgeries and records for 100 women were examined. Only 6% of women complained of post-operative headaches. However, 45% of women with history of migraines complained of post-operative headaches (p <0.001). Age was the only significant factor with women having post-operative headaches being significantly younger (p = 0.009).Conclusion: Post-operative headaches were more common in women with a pre-operative history of migraine headaches than in those without a history. Patients with a history of migraines should be warned of this risk.
Concise Review: The U.S. Food and Drug Administration and Regenerative Medicine
Authors: Witten Celia M. , McFarland Richard D. , Simek Stephanie L.
Published: October 2015

Regenerative medicine (RM) is a popular term for a field of scientific and medical research. There is not one universally accepted definition of RM, but it is generally taken to mean the translation of multidisciplinary biology and engineering science into therapeutic approaches to regenerate, replace, or repair tissues and organs. RM products have the potential to provide treatments for a number of unmet needs but have substantial scientific and regulatory challenges that need to be addressed for this potential to be fully realized. FDA has established formal regulatory definitions for biologics, medical devices, and combination products, as well as human cells and tissues. Regenerative medicine products regulated by FDA are classified on the basis of these definitions, and the classification forms the basis for determining the regulatory requirements to each specific product. FDA regulations are generally written to allow the agency flexibility to accommodate new scientific questions raised by novel and evolving technologies. FDA efforts to facilitate product development in this novel and promising area include working with individual sponsors, interacting with the scientific and industry communities, participating in standards development, and developing policy and guidance.

Significance

Regenerative medicine is generally taken to mean the translation of multidisciplinary biology and engineering science into therapeutic approaches to regenerate, replace, or repair tissues and organs. This article provides an overview of the efforts of the U.S. Food and Drug Administration (FDA) to facilitate product development in the field commonly known was regenerative medicine. It provides an introduction to the processes by which FDA works with individual sponsors, interacts with the scientific and industry communities, participates in standards development, and develops formal FDA policy and guidance.