bluuebunny/crossref_metadata_2025 huggingface dataset:
TSEE from Ion-Implanted LiF Crystals
Authors: Kawanishi Masaharu , Kakiage Toru , Kido Yoshiaki , Oda Keiji , Yamamoto Takayoshi
Published: March 2014

TSEE glow curves were studied for ion-implanted LiF single-crystals and for crystals irradiated by X-rays as well as those thermally annealed and irradiated by X-rays (afterward). It was found that the TSEE glow curve for Mg+ implanted LiF is influenced by the implantation energy and dose. Also, the annealed Mg+ implanted LiF (100 kV ×1012 Mg+/cm2) showed a greater response upon X-rays irradiation (compared with non-implanted LiF). Variations in the TSEE glow curves are qualitatively discussed.
TSEE from MgO Single Crystal Physically Processed
Authors: Fernando Jose , Chubachi Diniz , Kakiage Toru , Kawamoto Jun-ichi , Nakasaku Satoshi , Yamamoto Takayoshi , Kawanishi Masaharu , Watanabe Shigeo
Published: March 2014

Thermally stimulated exoelectron emission (TSEE) was studied for MgO single crystals. First, the TSEE response was measured for annealed or quenched samples. Some samples were ion-implanted by H+, He+ or Al+; then, after thermal annealing, the TSEE showed an increase relative to the non-implanted samples. This process was dependent on the element, energy and implanted dose. After a few reading cycles the TSEE of the ion-implanted samples started to decrease. However, upon re-annealing it increased once more. This showed that a fraction of the newly produced centers could be stabilized using a proper, yet still unknown, thermal treatment.
TL and TSEE Dosemeter of Cu+ Implanted Li2B4O7 Glass Ceramics
Authors: Kawamoto Takamichi , Tomita Akihiro , Kawanishi Masaharu
Published: March 2014

Simultaneous TL and TSEE measurements were carried out with Li2B4O7 glass ceramics in which Cu+ had been implanted and glass ceramics which were made of (Li2B4O7:Cu+SiO2+Pt). For all cases it was found that the TSEE responses were stable and reliable. However, the TL response of the Cu+-implanted samples showed a very unstable behavior, probably because the implanted Cu+ could not find stable sites in crystals under the heat treatment condition adopted in this experiment. It was also found that (Li2B4O7:Cu+SiO2+Pt) glass ceramics had good TL and TSEE responses as solid-state dosemeters.
A Method for Increasing the Exoelectron Detection Efficiency using Afterpulses in a Counter
Authors: Igarashi Ryuji , Narita Yuichi
Published: March 2014

Successful results for increasing the TSEE count using a gas flow GM counter to make full use of afterpulse is described. As has already been reported, afterpulses from a GM counter can occur, depending on the intensity of the incident ionizing radiation. The occurrence can be enhanced by a counter operation that transiently lowers the wire potential to a value negative to ground when a counter delivers an output pulse (INT–SW operation). This experiment showed us that an INT–SW operation can be used in some cases as a means to increase the TSEE detection efficiency or sensitivity.
Cylindrical Mirror Analyzer for Measuring Energy Spectrum of Photostimulated Exoelectrons
Authors: Yamamoto Shigeyuki , Yokogawa Hiroshi , Hashimoto Hiroshi
Published: March 2014

A cylindrical mirror analyzer (CMA) for measuring the energy spectrum of photostimulated exoelectrons has been designed. The CMA is equipped with a mirror mounted at an angle of 45° to the electron optical axis within an inner cylinder. Through the mirror, ultraviolet light can be focused on the surface of a specimen. Typical results obtained with this CMA are presented.
TSEE Responses of Oxides to Energetic Ion Bombardment
Authors: Huzimura Ryoitiro , Miyagawa Soji , Ato Yasuro , Kawanishi Masaharu
Published: March 2014

In this paper, the TSEE responses of oxides, mainly MgO, to bombardment with H+, He+, Ne+ and Ar+ in the energy range between 30 and 100 kev are presented. First, the relative yields of exoelectrons are explained by assuming the response function \int S(x)exp
(-x/λ)dx. S(x), the energy deposited due to nuclear and electronic collisions, is a function of the particle-penetration depth x and λ is the attenuation length for exoelectron emission. Numerical estimations of S(x) for ions impinging on MgO were made using Monte Carlo simulation data based on the Linhard theory. In experiments in a UHV system, significant TSEE peaks peculiar to heavy-ion bombardment were found and attributed to nuclear-collision effects by comparing the observed responses with the results estimated from the above functions. An electron excitation is found to produce sources for exoelectrons with λ≃200 Å inside the bulk as well as on the surfaces.
Keynote Paper on Exoelectron Emission Research
Authors: Scharmann A.
Published: March 2014

A survey of the exoelectron research that took place during the last 30 years, important results, potential applications and fundametal problems are given.
Equipment for Fast Automatic Readout of TSEE Dosemeters Employing a Wide-Range Proportional Counter
Authors: Kriegseis W. , Scharmann A. , Senger W. , Woerner B.
Published: March 2014

The influence of temperature and pressure of the counting gas on the characteristics and reproducibility of cylindrical proportional counters for exoelectron measurements is outlined and possibilities for an improved operation are described. For a fast readout of BeO thin-film dosemeters, a computer-controlled equipment has been constructed which employs a wide-range proportional counter, active pulse amplification, optical heating and temperature detection. The dosemeters are stored in input and output receptacles and are transported to the counting tube under processor control. A complete readout cycle of one sample occurs in about 30 s. The characteristic data of the dose measurements are printed out by a thermoprinter. The whole set of data is also available at a serial interface.
Role of Non-Stoichiometry in Exoelectron Oxide Emission II. Exoemission Activity
Authors: Kortov V. S.
Published: March 2014

Various types of oxide exoemission activities have been considered. Changes in the exoemission activity at stoichiometry violations have been used for technical purposes.
Kinetics of Exoelectron After-Emission from MgO
Authors: Matsumura Keiko , Huzimura Ryoitiro
Published: March 2014

Having found a reproducible after-emission for MgO in a UHV-AES system, we studied its kinetics using two models:(I) a tunneling recombination of trapped electrons and holes and (II) a diffusion-controlled recombination of active species. A numerical analysis showed that only model II can explain the after-emission.
Exoemission Excitation of Ferroelectrics in Vacuum by Alternating Voltage
Authors: Sujak B. , Biedrzycki K.
Published: March 2014

Measurements of exoemission under vacuum conditions from KDP (KH2PO4) single crystals during continuous repolarization by an alternating voltage have been performed. The temperature position of the main peak of the exoelectron emission intensity observed on the TSEE curve coincided with the phase-transition temperature (123 K) of KH2PO4 crystalline samples. It has been found that TSEE curves are reproducible in the vicinity of the Curie temperature region under continuous excitation with an alternating voltage.
Effect of Phase Transitions on the TSEC and TSEE from Solid Methanol
Authors: Otop H. , Sujak B.
Published: March 2014

Thermally Stimulated Electric Current (TSEC) and Thermally Stimulated Exoemission (TSEE) from solid methanol have been measured during a cooling process in the temperature range 170–80 K. Both TSEC and TSEE result from the subjugation of solid methanol to a temperature ramp.
It has been found that both TSEC and TSEE intensities depend strongly on whether or not a methanol sample has been cooled diretly from the liquid phase. It has also been found that the TSEC intensity increases with the temperature difference which exists across a sample during the solidification process, whereas the TSEE peak value remains approximately constant for the same conditions. Also, a non-stable broadening of peaks could be observed.
Measurement System for Longitudinal and Shear Waves in Solids under Shock Compression in Several Tens of GPa Region Combined with the Keyed-Powder Gun
Authors: Mashimo Tsutomu , Nagayama Kunihito
Published: March 2014

A measurement system for both longitudinal and shear waves in solids under shock compression in several 10 s of GPa region has been developed. In this system, combined compression-shear waves in solids are generated by the oblique-parallel-plate impact method using the keyed-powder gun, which is capable of accelerating a projectile without rotation to velocities of over 2 km/s. The particle-velocity histories of both longitudinal and shear waves are measured by an electromagnetic gauge method using pulsive-oblique magnetic field and Faraday gauges.
Measurements of Underwater Sound Absorption Coefficient by the Reverberation Method
Authors: Takahashi Sumio , Kikuchi Toshiaki , Ogura Akiteru
Published: March 2014

Measurements of underwater sound absorption coefficient are carried out on ten sample materials by the reverberation method using a reverberation water tank. In order to record short reverberation time in the tank, a digital memory is used. Measured absorption coefficient values are plotted against transmission loss of the samples, and the method is shown to be useful for the evaluation of underwater sound absorbing materials.
Ultrasonic Measurement on Water Suspension of Small Particle Flowing through a Tube as a Model of Biological Substance
Authors: Shiokawa Showko , Unno Yoshihiro , Moriizumi Toyosaka , Iehisa Nobuaki
Published: March 2014

A new technique for a flow-cytometer using an ultrasonic measurement system has been proposed and experimentally studied. The present measuring equipment utilizes a high-precision phase detection system using arched IDT's. As a model of biological substance, a particle-solution medium which consists of a suspension of polymethyl-methacrylate spheres in a water solution flowing through a tube was used. The phase was measured as a function of the particle concentration, size and density. The experimental results showed that the present technique may be applicable to an ultrasonic cytometer.
Propagation Characteristics of SAW on a ZnO/SiO2/high-velocity-substrate Structure
Authors: Yamaguchi Masatsune , Tanno Masayuki , Hashimoto Ken-ya , Kogo Hiroshi
Published: March 2014

The paper describes surface acoustic wave (SAW) propagation on a ZnO/SiO2/high-velocity-alumina-substrate multi-layered structure. It was shown that, quite independent of the elastic properties of the alumina substrate, the electromechanical coupling factor k
2 and temperature coefficient of frequency (TCF) reflect those for Lamb waves in a ZnO/SiO2 composite membrane. This suggests a simple guiding principle to find multi-layered structures with moderate temperature stability and k
2 for SAW, that is, TCF could be compensated without greatly reducing k
2 by the proper choice of substrate materials.
5 GHz Range SAW Filter Fabricated by Electron Beam Exposure with O2-Plasma Ashing Techniques
Authors: Yamanouchi Kazuhiko , Meguro Toshiyasu , Chen Zhuo Hui
Published: March 2014

High performance filters in the GHz range are required in communication systems. In this paper, fine electrodes of the order of 0.187 µm width have been fabricated using electron beam lithography, normal lift-off techniques and O2-plasma cleaning system. These techniques have been applied to surface acoustic wave (SAW) filters in the GHz range. We performed experiments with the filters at 5 GHz. Filters with minimum insertion loss of 15.0 dB at the center frequency of 5 GHz were obtained. We also describe and demonstrate some new single phase unidirectional transducers (SPUDT) utilizing self-aligned angle evaporation techniques with low loss and no ripples. The experimental results show a directivity of 18.0 dB/transducer at about 500 MHz and 10.0 dB at about 2 GHz.
Effect of Eddy Current Loss on the Propagation Properties of Magneto-Surface-Acoustic-Waves in Highly Magnetostrictive Alloy Film Deposited on Glass Substrate
Authors: Inoue Mitsuteru , Tsuboi Yoshihiro , Makita Akihiko , Fujita Naoyuki , Miyama Tomohiro , Fujii Toshitaka
Published: March 2014

Propagation properties of magneto-surface-acoustic-waves (MSAWs) in highly magnetostrictive alloy films formed on glass substrates are analyzed using the “matrix approach”. The analysis reveals that MSAWs appearing in this configuration are two modes of the Rayleigh-type and the Love-type SAWs. The velocity and attenuation of these two modes of waves versus drive frequency vary in a different manner depending strongly on the easy axis orientation of the uniaxial magnetic anisotropy in the film plane, which reflects the fact that the coupling between the spin and the elastic system is different.
Ultrasonic Plastic Welding with Welding Tip Pair
Authors: Tsujino Jiromaru , Kenmotsu Kazuya , Fujita Hiroaki , Ishikawa Susumu
Published: March 2014

Ultrasonic plastic micro-welding with transverse and longitudinal vibration welding tip pairs is studied. (1) A welding tip pair of 20 kHz vibrating perpendicularly, and (2) a welding tip pair of 20 kHz and 27 kHz vibrating parallel to the surfaces to be welded are used for micro-welding of plastic sheet specimens. The welding tips are arranged parallel to each other with a small gap and driven at antiphase vibration mode. Using these welding tip pairs, welding specimens are joined with very narrow width from the upper part of lapped specimens according to the gap distance with no damage to the lower part of the specimens.
Low Temperature Acoustic Microscopy at Ultrasonic Frequencies
Authors: Cheeke J. D. N. , Germain L.
Published: March 2014

We describe a transmission mode technique in acoustic microscopy which is well adapted to low temperature work in which the receiving transducer is placed at the focal plane. Examples of images at room temperature and helium temperatures are given and some of the difficulties and particularities of helium imaging are described. We also present preliminary results of studies of nonlinear effects in water, liquid nitrogen and liquid helium with the SAM and the direct observation of higher order harmonics using the focal plane detection technique.
Enhancement of Ultrasonic Testing Equipment Time Based Resolution by Synthetic Waveform Generator
Authors: Ohta Koji , Watanabe Takeharu , Kojima Chihiro , Yamada Hiroaki
Published: March 2014

To upgrade time based resolution of angle beam probes in ultrasonic material testing, the deconvolution inverse filter has been developed. It can be used in the field with a conventional ultrasonic flaw detector. The filter function must be transferred into the time domain by a computer, and calculation results are written on the ROM. In the field, the contents of the ROM are read, D/A converted, and the angle beam probe is excited by this wave form. A computer is not necessary to use the inverse filter in the field.
Ion Beam Excited Acoustic Image and Specific Element Image of Teeth
Authors: Tateno Hiroto , Ono Teruo , Iwashita Youichirou , Kawano Kazunori , Noikura Takenori
Published: March 2014

The ion beam excited acoustic microscope (IAM) is a new microscope which provides visual representations of the elastic waves caused by localized chopping ion energy. Topographs of ultrasonic attenuation and local elastic variations were obtained by measuring frequency and amplitude at a composite resonant point between transducer and sample. Specific ion images were also obtained from the same measurement. In this paper, the IAM and observed topographs and intensity modulated images of the specific ions are described. The elasticity of the hydroxyapatite crystal of the teeth is examined.
Electron-Acoustic Microscopic Study on Dislocation Lines in the Base Region of npn Si–Tr
Authors: Takenoshita Hiroshi
Published: March 2014

Using an npn Si–Tr chip, bias voltage was applied between the collector and the base for in situ observation of SEM and electron-acoustic microscopy (EAM) in the same area. The results disclosed the following. (1) The contrast of electron acoustic image (EAI) of EAM varied with the bias conditions. (2) Dislocation lines were observed in the base region but not in the emitter region. (3) The dislocation lines in the EAI were not observed at bias voltage of 0 V but appeared at 0.4 V to the collector. (4) By using at acceleration voltage of 30 kV and Si as a specimen, the observation depth by EAM was about 10 µm. EAM study of another type of Tr chips was also undertaken.
Generation of Lamb Wave Using Linear Array Probe and Its Application for Flaw Detection
Authors: Jitsumori Akio , Inoue Satoru , Maekawa Takaaki , Inari Takahiko
Published: March 2014

The method with which a Lamb wave of the required mode is generated and detected by electronically adjusting the incident angle using a linear array probe, and its application to flaw detection is presented. To test the ability of this method, experiments were carried out using specimens with an artificial flaw. The method was shown to be successful. The two dimensional CRT display method of the detected flaws, in which the polar coordinates consist of the propagation time and the incident angle of the wave, and the brightness corresponds to the amplitude of echo is also presented.
Inspection of Interior Adhesion in Plywood by Means of Acoustic Emission
Authors: Yoshimura Noboru , Ogasawara Yuji , Kodaki Mitsukazu , Asari Koichi , Nishida Makoto , Okuyama Daitaro
Published: March 2014

A trial inspection was made of interior adhesion in plywood using the acoustic emission (AE) method. A bending test investigated the relation between AE characteristics and samples with and without adhesion in plywood. It was found that for sample C without adhesion AE started to count at an early stage of mechanical load. Also, sample C gave various amplitudes in the range from 30 kHz to 100 kHz even at an early stage of mechanical load.
Photoacoustic Imaging in the Vicinity of Phase Transition Temperature
Authors: Kojima Seiji
Published: March 2014

A scanning laser photoacoustic microscope has been manufactured and first applied to the study of a phase transition. It has been found for the melting of gallium that the state in which the solid and liquid phases coexist can be observed clearly by this method. The spatial variation of photoacoustic signals is discussed with regard to the temperature variation data.
SAW Propagation Properties in Ta2O5 Strip Waveguide for Waveguide-Type Acousto-Optic Devices
Authors: Goto Nobuo , Miyazaki Yasumitsu
Published: March 2014

SAW (surface acoustic wave) channel waveguides are expected to improve acousto-optic (A–O) interaction efficiency and integration density in construction. Thin strips of Ta2O5 and Al-coated Ta2O5 showed excellent properties as 3-dimensional SAW waveguides on LiNbO3. Propagation loss in the 100 µm-width Ta2O5 strip was about 1 dB for
40∼100 MHz. Coupling loss of SAW excited by a focused IDT into the waveguide was 2 dB. Stronger field confinement was obtained in a wider frequency range by overlaying thin Al on the Ta2O5 strip than Ta2O5 alone. These waveguides are useful for A–O devices of optical processing and communication.
Nondestructive Evaluation of Materials by Photoacoustic Microscope and Photothermal Beam Deflection
Authors: Kasai Masanobu , Sawada Tsuguo , Watanabe Yohichi Gohshi Tomoharu , Furuya Keiichi
Published: March 2014

Photothermal beam deflection (PBD) is a new photoacoustic inspection technique, which has the assets of being both nondesstructive and noncontact. In this paper, PBD signals were anlyzed and compared with PAM signals experimentally. PBD image for the oside layer on the surface of stainless steel was demonstrated as one PBD application.
Effects of Liquid Viscosity on Ultrasonic Propagation in Liquid/Solid Structure
Authors: Kikuchi Tsuneo , Moriizumi Toyosaka
Published: March 2014

The purpose of this paper is to describe the effects of liquid viscosity on ultrasonic propagation in a liquid/solid structure. Two types of propagation system were assumed: one was the solid/liquid structure, and the other was the solid/liquid/solid structure. In the former case, leaky SAW propagating along the interface was perturbed by the shear stress caused by the liquid viscosity. In the latter case guided waves propagating in the liquid layer were influenced by viscosity if the viscous penetration depth was comparable with the liquid thickness.
Study of Dislocations in CsI by Simultaneous Measurements of Ultrasonic Velocity and Attenuation
Authors: Koizumi Hirokazu , Iwasa Izumi , Kakumoto Munenari , Suzuki Takayoshi
Published: March 2014

A new ultrasonic measuring system which enables automatic and simultaneous measurements of sound velocity v and attenuation α was constructed. Using this system, changes in v and α by plastic deformation were measured for a CsI and a CsI–CsBr mixture in the temperature range of 1.5–80K. The low temperature experimental results can be accounted for by the interaction of dislocations and obstacles, Peierls potential or Br impurities.
Surface Elastic Wave in Point Group 6̄
Authors: Kameyama Hiroshi
Published: March 2014

It is proved without any assumption of quasi-static approximation that a Rayleigh-mode piezoelectric surface wave can be propagated in the sagittal plane in a case when that plane is not a mirror plane in the point group of 6̄-C
3h. It is also shown that a Bleustein-Gulyaev wave can be propagated in a sagittal plane which is not perpendicular to the axis of two-fold rotation.
Ultrasonic Linear Array Probe with Triple Acoustic Matching Layers
Authors: Ohta Masaya , Inoue Takeshi , Takahasi Sadayuki
Published: March 2014

This paper is concerned with an ultrasonic linear array probe with triple acoustic matching layers. The probe is designed with multiple-mode filter theory, because it has four-fold resonant modes adjacent reciprocally. The optimum specific acoustic impedances and thicknesses for individual acoustic matching layers are computed. A linear array probe with 3.5 MHz center frequency is trially produced. The obtained probe data shows wide-band, high-efficiency, low-ripple characteristics. Measured fractional 6 dB bandwidth, tuned by series inductor, is 94%. With this probe, distance resolution is improved in tomograms obtained with medical diagnostic equipment.
Transducers, Sensors, and Actuators
Authors: Newnham Robert E.
Published: March 2014

We review some of the basic ideas underlying composite electroceramics. The ideas will be illustrated with electromechanical transducers, sonochemical sensors, active vibration absorbers, electronic actuators, and a variety of other applications-both real and imagined.
Wide-band Multi-layer Ultrasonic Transducers Made of Piezoelectric Films of Vinylidene Fluoride-Trifluoroethylene Copolymer
Authors: Sakaguchi Kousaku , Sato Takashi , Koyama Kiyohito , Ikeda Susumu , Yamamizu Shuichiro , Wada Yasaku
Published: March 2014

Piezoelectric films of vinylidene fluoride-trifluoroethylene copolymer are applied to construct a wide-band ultrasonic transducer with multi-layered structure. One of the component films has a polarization direction opposite to the others. Amplitudes of even- and odd- resonances are adjusted by combination of copolymer films with different thicknesses. A wide-band transducer whose bandwidth in more than twice that of a single-layer transducer is obtained. The design principle and the method for preparing this wide-band transducer are presented.
Measurement of Finite Amplitude Ultrasound Wave Fields by Light Beam CT
Authors: Akiyama Iwaki , Nishida Yukihiro , Waki Hisao , Nakajima Masato , Yuta Shin-ichi
Published: March 2014

This paper describes an optical method to observe wave form distortion due to the finite amplitude ultrasound propagation. Distribution of magnitude and phase of each harmonic component in the plane normal to ultrasound beam axis is reconstructed from the diffraction spectrum through CT algorithm.
Two new species and a new combination in the lichen genus Pertusaria in Brazil
Authors: Archer Alan W. , Elix John Alan
Published: March 2014

Two new species, Pertusaria marcellii and P. saxatilis are reported from Brazil and the new combination Pertusaria ferax (Müll.Arg.) A.W.Archer & Elix is made.
Feasibility of Non-Coplanar Tomotherapy for Lung Cancer Stereotactic Body Radiation Therapy
Authors: Yang Wensha , Jones Ryan , Lu Weiguo , Geesey Constance , Benedict Stanley , Read Paul , Larner James , Sheng Ke
Published: March 2014

To quantify the dosimetric gains from non-coplanar helical tomotherapy (HT) arcs for stereotactic body radiation therapy (SBRT) of lung cancer, we created oblique helical arcs by rotating patient's CT images. Ten, 20 and 30 degrees of yaws were introduced in the treatment planning for a patient with a hypothetical lung tumor at the upper, middle and lower portion of the right lung, and the upper and middle left lung. The planning target volume (PTV) was 43 cm3. 60 Gy was prescribed to the PTV. Dose to organs at risk (OARs), which included the lungs, heart, spinal cord and chest wall, was optimized using a 2.5 cm jaw, 0.287 pitch and modulation factor of 2.5. Composite plans were generated by dose summation of the resultant plans. These plans were evaluated for its conformity index (Rx) and percentile volume of lung receiving radiation dose of x Gy (Vx). Conformity index was defined by the ratio of x percent isodose volume and PTV. The results show that combination of non-coplanar arcs reduced R50 by 4.5%, R20 by 26% and R10 by 30% on average. Non-coplanar arcs did not affect V20 but reduced V10 and V5 by 10% and 24% respectively. Composite of the non-coplanar arcs also reduced maximum dose to the spinal cord by 20–39%. Volume of chest wall receiving higher than 30 Gy was reduced by 48% on average. Heart dose reduction was dependent on the location of the PTV and the choice of non-coplanar orientations. Therefore we conclude that non-coplanar HT arcs significantly improve critical organ sparing in lung SBRT without changing the PTV dose coverage.
A Two-Step Optimization Method for Improving Multiple Brain Lesion Treatments with Robotic Radiosurgery
Authors: Ma L. , Sahgal A. , Hwang A. , Hu W. , Descovich M. , Chuang C. , Barani I. , Sneed P. K. , McDermott M. , Larson D. A.
Published: March 2014

Planning robotic radiosurgery treatments for multiple (n > 3) metastatic brain lesions is challenging due to the need of satisfying a large number of dose-volume constraints and the requirement of prescribing different dose levels to individual targets. In this study, we developed a sequential two-step optimization technique to improve the planning quality of such treatments. In contrast to the conventional approach of where all targets are simultaneously planned, we have developed a two-step optimization method. In this method, the first step was to create treatment plans for individual targets. In the second step, the 3D dose matrices associated with each plan were exported to Dicom-RT digital files and subsequently optimized. For the optimization, a singular-value-decomposition (SVD) algorithm was implemented to minimize the dose interferences among different targets. Finally, we compared the optimized treatment plans with the treatment plans created using the conventional method to determine the effectiveness of the new method. Large improvements in target dose distributions as well as normal brain sparing were found for the two-step optimization treatment plans as compared with the conventional treatment plans. The two-step optimization significantly lowered the volume of normal brain receiving relatively low doses. For example, the normal brain volume receiving 12-Gy was reduced by averaged 42% (range 34%–47%) with the two-step optimization. Such improvements generally enlarged with increasing number of targets being treated regardless of target sizes. Of note, normal brain dose was found to increase non-linearly with increasing number of targets. In summary, a two-step optimization technique is demonstrated to significantly improve the treatment plan quality as well as reduce the planning effort for multi-target robotic radiosurgery.
The Improvement of Irreversible Electroporation Therapy Using Saline-Irrigated Electrodes: A Theoretical Study
Authors: Adeyanju Oyinlolu. O. , Al-Angari Haitham M. , Sahakian A. V.
Published: March 2014

Irreversible electroporation (IRE) is a novel therapy used to ablate tumors with high-field electric pulses applied in short durations. It is important to reduce the generation of heat in IRE to avoid the harmful effects of thermal damage. The objective of this simulation study was to examine the effects of saline irrigation in the reduction of heat upon electrodes used in IRE treatment of hepatocellular carcinoma. We used a two dimensional Finite Element Model of a tumor in a liver with electrodes placed at the center of the tumor. We simulated a typical electroporation protocol with varying thicknesses and conductivities of the saline layer, and we observed the maximum temperature and the distribution of the electric field and temperature in the tissue. Our results showed that the maximum temperature in the tissue decreases with the use of saline, but the surface area of the tumor that could potentially be thermally damaged may increase with the thickness and conductivity of the saline. With the use of saline, one can achieve upwards of a 17% reduction of the maximum temperature at the electrodes. Also, the distribution of temperature and the electric field becomes more homogenous between the electrodes as the conductivity of the saline layer increases for all thicknesses of saline. We conclude that irrigating electrodes with saline may be an effective measure to enhance the efficacy of irreversible electroporation by reducing the maximum temperature at the electrodes and also improving the extent and distribution of the electric field in the tissue. However, the properties of the saline should be adjusted so as to limit the increase of thermal damage propagated in the tissue.
Anti-angiogenesis by Lentivirus-Mediated Small Interfering RNA Silencing of Angiopoietin-2 Gene in Pancreatic Carcinoma
Authors: Zhou J. , Zhang Z-X. , Zhao H. , Zhu D-M. , Zhang Y. , Li D-C.
Published: March 2014

Angiopoietin-2 (Ang2) has been shown highly expressed in resected human pancreatic carcinoma samples, but the role of it is less clear. We were, therefore, interested in exploring the effects of Ang2 silencing on the angiogenesis and growth of pancreatic carcinoma. Lentivirus mediated Ang2 small hairpin RNA (LV-RNAi) were transfected into pancreatic carcinoma cell line MIA PaCa-2. Three groups were designed in this study: the control group (Mia PaCa-2 cells), the LV-NC group (cells transfected with the control GFP-lentivirus) and the LV-RNAi group (cells transfected with LV-RNAi). The mRNA and protein level of Ang2 gene were detected by real-time polymerase chain reaction and Western blot respectively. MTT assay and Flow Cytometry were used to detect the cell growth and apoptosis. Anti-angiogenesis effect was measured by chick embryo chorioallantoic membrane (CAM) assay. In nude mice bearing tumors, after treatment with intratumoral injection of LV-RNAi, mice growth and tumor volume were observed, and the expression of Ang2, VEGF and CD34 were measured by immunohistochemistry. Compared with the control group and the LV-NC group, the mRNA and protein level of Ang2 gene were successfully knocked down in LV- RNAi group. Also the vessel count was decreased in CAM assay after LV-RNAi transfection. Meanwhile, no obvious cell viability and apoptosis changes were found in MTT assay and Flow Cytometry, respectively. LV-RNAi inhibited pancreatic carcinoma angio- genesis and growth by downregulating the expression of VEGF and CD34. These findings demonstrate that Ang2 gene silencing may exert a anti-angiogenesis effect in vitro and in vivo, and Ang2 targeted gene therapy has the potential to serve as a novel way for pancreatic carcinoma treatment.
First forecast of a sudden stratospheric warming with a coupled whole‐atmosphere/ionosphere model IDEA
Authors: Wang H. , Akmaev R. A. , Fang T.‐W. , Fuller‐Rowell T. J. , Wu F. , Maruyama N. , Iredell M. D.
Published: March 2014

We present the first “weather forecast” with a coupled whole‐atmosphere/ionosphere model of Integrated Dynamics in Earth's Atmosphere (IDEA) for the January 2009 Sudden Stratospheric Warming (SSW). IDEA consists of the Whole Atmosphere Model and Global Ionosphere‐Plasmasphere model. A 30 day forecast is performed using the IDEA model initialized at 0000 UT on 13 January 2009, 10 days prior to the peak of the SSW. IDEA successfully predicts both the time and amplitude of the peak warming in the polar cap. This is about 2 days earlier than the National Centers for Environmental Prediction operational Global Forecast System terrestrial weather model forecast. The forecast of the semidiurnal, westward propagating, zonal wave number 2 (SW2) tide in zonal wind also shows an increase in the amplitude and a phase shift to earlier hours in the equatorial dynamo region during and after the peak warming, before recovering to their prior values about 15 days later. The SW2 amplitude and phase changes are shown to belikelydue to the stratospheric ozoneand/orcirculation changes. The daytime upward plasma drift and total electron content in the equatorial American sector show a clear shift to earlier hours and enhancement during and after the peak warming, before returning to their prior conditions. These ionospheric responses compare well with other observational studies. Therefore, the predicted ionospheric response to the January 2009 SSW can be largely explained in simple terms of the amplitude and phase changes of the SW2 zonal wind in the equatorialEregion.
Ultrasmall Dispersible Crystalline Nickel Oxide Nanoparticles as High‐Performance Catalysts for Electrochemical Water Splitting
Authors: Fominykh Ksenia , Feckl Johann M. , Sicklinger Johannes , Döblinger Markus , Böcklein Sebastian , Ziegler Jürgen , Peter Laurence , Rathousky Jiri , Scheidt Ernst‐Wilhelm , Bein Thomas , Fattakhova‐Rohlfing Dina
Published: March 2014

Ultrasmall, crystalline, and dispersible NiO nanoparticles are prepared for the first time, and it is shown that they are promising candidates as catalysts for electrochemical water oxidation. Using a solvothermal reaction in tert‐butanol, very small nickel oxide nanocrystals can be made with sizes tunable from 2.5 to 5 nm and a narrow particle size distribution. The crystals are perfectly dispersible in ethanol even after drying, giving stable transparent colloidal dispersions. The structure of the nanocrystals corresponds to phase‐pure stoichiometric nickel(ii) oxide with a partially oxidized surface exhibiting Ni(iii) states. The 3.3 nm nanoparticles demonstrate a remarkably high turn‐over frequency of 0.29 s–1 at an overpotential of g = 300 mV for electrochemical water oxidation, outperforming even expensive rare earth iridium oxide catalysts. The unique features of these NiO nanocrystals provide great potential for the preparation of novel composite materials with applications in the field of (photo)electrochemical water splitting. The dispersed colloidal solutions may also find other applications, such as the preparation of uniform hole‐conducting layers for organic solar cells.
Liquid Metal/Metal Oxide Frameworks
Authors: Zhang Wei , Ou Jian Zhen , Tang Shi‐Yang , Sivan Vijay , Yao David D. , Latham Kay , Khoshmanesh Khashayar , Mitchell Arnan , O'Mullane Anthony P. , Kalantar‐zadeh Kourosh
Published: March 2014

A new platform described as the liquid metal/metal oxide (LM/MO) framework is introduced. The constituent spherical structures of these frameworks are made of micro‐ to nanosized liquid metal spheres and nanosized metal oxides, combining the advantages of both materials. It is shown that the diameters of the spheres and the stoichiometry of the structures can be actively controlled. Additionally, the liquid suspension of these spheres demonstrates tuneable plasmon resonances. These spherical structures are assembled to form LM/MO frameworks which are capable of demonstrating high sensitivity towards low concentrations of heavy metal ions, and enhanced solar light driven photocalalytic activities. These demonstrations imply that the LM/MO frameworks are a suitable candidate for the development of future high performance electronic and optical devices.
Nano‐antennae assisted emission of extreme ultraviolet radiation
Authors: Pfullmann Nils , Noack Monika , Cardoso de Andrade José , Rausch Stefan , Nagy Tamas , Reinhardt Carsten , Knittel Vanessa , Bratschitsch Rudolf , Leitenstorfer Alfred , Akemeier Dieter , Hütten Andreas , Kovacev Milutin , Morgner Uwe
Published: March 2014

High‐order harmonic generation in xenon with oscillator repetition rates is studied. The necessary intensity is reached via plasmonic field enhancement at nanostructured arrays of bow‐tie gold antennae. The theoretical analysis focuses on the thermal properties and the damage threshold of the bow‐tie antennae. On the experimental side the number of contributing atoms is determined and optimized. Extreme ultraviolet radiation is successfully observed with photon fluxes almost an order of magnitude larger than previously reported.
Anti‐Tuberculosis Evaluation and Conformational Study of N‐Acylhydrazones Containing the Thiophene Nucleus
Authors: Cardoso Laura N. F. , Bispo Marcelle L. F. , Kaiser Carlos R. , Wardell James L. , Wardell Solange M. S. V. , Lourenço Maria C. S. , Bezerra Flávio A. F. M. , Soares Rodrigo P. P. , Rocha Marcele N. , de Souza Marcus V. N.
Published: March 2014

A series of N‐acylhydrazonyl‐thienyl derivatives (compounds 2 and 3), mainly of the type 2‐(aryl‐CHNNHCOCH2)‐thiene (2: aryl = substituted‐phenyl; 3: aryl = heteroaryl) were evaluated against Mycobacterium tuberculosis. Particularly active compound was 3 (heteroaryl = 5‐nitrothien‐2‐yl or 5‐nitrofuran‐2‐yl) with MIC values of 8.5 and 9.0 μM, respectively. Moderately active compounds were compound 3 (heteroaryl = pyridin‐2‐yl) and compound 2 containing aryl = 2‐ or 4‐hydroxyphenyl groups, with MIC values between 170 and 408 μM. Compound 2 containing OMe, H, F, Cl, Br, CN, and NO2 substituents and compound 3 (heteroaryl = furan‐2‐yl, thien‐2‐yl, pyrrol‐2‐yl, imidazol‐2‐yl, pyridin‐3‐yl, and pyridin‐4‐yl) were all inactive. Clearly, there is no correlation of activity with the electronic effects of the substituents. The activities suggest different modes of biological action of the compounds having nitro‐heteroaryl groups, on the one hand, and the 2‐hydroxyphenyl or pyridin‐2‐yl substituents, on the other hand. Compounds having 2‐ or 4‐hydroxyphenyl, 2‐hydroxy‐5‐nitrophenyl, or 4‐hydroxy‐3‐chlorophenyl were less cytotoxic than ethambutol. It is important to notice that compound 3 (aryl = 5‐NO2‐furan‐2‐yl) exhibited a promising therapeutic index (TI = 1093.90), with a value 4.4 less than that of ethambutol. Compounds 2 and 3 exist in DMSO or MeOD solutions as mixtures of EC(O)N/ECN and ZC(O)N/ECN conformers.
The selective conversion of glutamic acid in amino acid mixtures using glutamate decarboxylase—a means of separating amino acids for synthesizing biobased chemicals
Authors: Teng Yinglai , Scott Elinor L. , Sanders Johan P. M.
Published: March 2014

Amino acids (AAs) derived from hydrolysis of protein rest streams are interesting feedstocks for the chemical industry due to their functionality. However, separation of AAs is required before they can be used for further applications. Electrodialysis may be applied to separate AAs, but its efficiency is limited when separating AAs with similar isoelectric points. To aid the separation, specific conversion of an AA to a useful product with different charge behavior to the remaining compounds is desired. Here the separation of L‐aspartic acid (Asp) and L‐glutamic acid (Glu) was studied. L‐Glutamate α‐decarboxylase (GAD, Type I, EC 4.1.1.15) was applied to specifically convert Glu into γ‐aminobutyric acid (GABA). GABA has a different charge behavior from Asp therefore allowing a potential separation by electrodialysis. Competitive inhibition and reduced operational stability caused by Asp could be eliminated by maintaining a sufficiently high concentration of Glu. Immobilization of GAD does not reduce the enzyme's initial activity. However, the operational stability was slightly reduced. An initial study on the reaction operating in a continuous mode was performed using a column reactor packed with immobilized GAD. As the reaction mixture was only passed once through the reactor, the conversion of Glu was lower than expected. To complete the conversion of Glu, the stream containing Asp and unreacted Glu might be recirculated back to the reactor after GABA has been removed. Overall, the reaction by GAD is specific to Glu and can be applied to aid the electrodialysis separation of Asp and Glu. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:681–688, 2014
Enhancement of the antimicrobial properties of bacteriophage‐K via stabilization using oil‐in‐water nano‐emulsions
Authors: Esteban Patricia Perez , Alves Diana R. , Enright Mark C. , Bean Jessica E. , Gaudion Alison , Jenkins A.T.A. , Young Amber E.R. , Arnot Tom C.
Published: March 2014

Bacteriophage therapy is a promising new treatment that may help overcome the threat posed by antibiotic‐resistant pathogenic bacteria, which are increasingly identified in hospitalized patients. The development of biocompatible and sustainable vehicles for incorporation of viable bacterial viruses into a wound dressing is a promising alternative. This article evaluates the antimicrobial efficacy of Bacteriophage K against Staphylococcus aureus over time, when stabilized and delivered via an oil‐in‐water nano‐emulsion. Nano‐emulsions were formulated via thermal phase inversion emulsification, and then bacterial growth was challenged with either native emulsion, or emulsion combined with Bacteriophage K. Bacteriophage infectivity, and the influence of storage time of the preparation, were assessed by turbidity measurements of bacterial samples. Newly prepared Bacteriophage K/nano‐emulsion formulations have greater antimicrobial activity than freely suspended bacteriophage. The phage‐loaded emulsions caused rapid and complete bacterial death of three different strains of S. aureus. The same effect was observed for preparations that were either stored at room temperature (18–20°C), or chilled at 4°C, for up to 10 days of storage. A response surface design of experiments was used to gain insight on the relative effects of the emulsion formulation on bacterial growth and phage lytic activity. More diluted emulsions had a less significant effect on bacterial growth, and diluted bacteriophage‐emulsion preparations yielded greater antibacterial activity. The enhancement of bacteriophage activity when delivered via nano‐emulsions is yet to be reported. This prompts further investigation into the use of these formulations for the development of novel anti‐microbial wound management strategies. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:932–944, 2014
Physiological description of multivariate interdependencies between process parameters, morphology and physiology during fed‐batch penicillin production
Authors: Posch Andreas E. , Herwig Christoph
Published: March 2014

Optimization of productivity and economics of industrial bioprocesses requires characterization of interdependencies between process parameters and process performance. In the case of penicillin production, as in other processes, process performance is often closely interlinked with the physiology and morphology of the organism used for production. This study presents a systematic approach to efficiently characterize the physiological effects of multivariate interdependencies between bioprocess design parameters (spore inoculum concentration, pO2 control level and substrate feed rate), morphology, and physiology. Method development and application was performed using the industrial model process of penicillin production. Applying traditional, statistical bioprocess analysis, multivariate correlations of raw bioprocess design parameters (high spore inoculum concentration, low pO2 control as well as reduced glucose feeding) and pellet morphology were identified. A major drawback of raw design parameter correlation models; however, is the lack of transferability across different process scales and regimes. In this context, morphological and physiological bioprocess modeling based on scalable physiological parameters is introduced. In this study, raw parameter effects on pellet morphology were efficiently summarized by the physiological parameter of the biomass yield per substrate. Finally, for the first time to our knowledge, the specific growth rate per spore was described as time‐independent determinant for switching from pellet to disperse growth during penicillin production and thus introduced as a novel, scalable key process parameter for pellet morphology and process performance. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:689–699, 2014
Edinburgh datashare – reflections from a data repository manager
Authors: Rice Robin
Published: March 2014

EDITOR'S SUMMARY

A no‐cost data repository service for university researchers, the Edinburgh DataShare has grown from a demonstration project to an integral part of the research data management (RDM) initiative of the University of Edinburgh. The initiative is designed to serve data management planning, data storage, data stewardship and data support, as well as provide a data asset registry and a vault where data will be retained for a period of time. Pilot testing the repository and RDM services has led to changes in the interface and workflow to improve usability. Testing by a clinical health instructor raised questions about anonymized patient data, confidentiality and vulnerability to hacking and led to a decision to cap the embargo on data access at five years. Additional testing for very large datasets and multimedia datasets remains to be done to determine the minimum amount of data fields that will serve a variety of purposes.
Response‐dependent two‐phase sampling designs for biomarker studies
Authors: McIsaac Michael A. , Cook Richard J.
Published: March 2014

Two‐phase sampling designs are developed and investigated for use in the context of a rheumatology study where interest lies in the association between a biomarker with an expensive assay and disease progression. We derive optimal phase‐II stratum‐specific sampling probabilities for analyses from parametric maximum likelihood (ML), mean score (MS), inverse probability weighted (IPW) and augmented inverse probability weighted estimating equations (AIPW). The easy‐to‐implement optimally efficient design for the MS estimator is found to be asymptotically optimal for the IPW and AIPW estimators we consider, and is shown to result in efficiency gains over balanced and simple random sampling even when analyses are likelihood‐based. We further demonstrate the robustness of this optimal design and show that it results in very efficient estimation even when the model or parameters used in its derivation are misspecified. The Canadian Journal of Statistics 42: 268–284; 2014 © 2014 Statistical Society of Canada