bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased lung clearance of isoflurane shortens emergence in obesity: a prospective randomized‐controlled trial
Authors: KATZNELSON R. , NAUGHTON F. , FRIEDMAN Z. , LEI D. , DUFFIN J. , FEDORKO L. , WASOWICZ M. , VAN RENSBURG A. , MURPHY J. , FISHER J. A.
Published: July 2011

Background: There is a concern that obesity may play a role in prolonging emergence from fat‐soluble inhalational anaesthetics. We hypothesized that increased pulmonary clearance of isoflurane will shorten immediate recovery from anaesthesia and post‐anaesthesia care unit (PACU) stay in obese patients.

Methods: After Ethics Review Board approval, 44 ASA I–III patients with BMI>30 kg/m2 undergoing elective gynaecological or urological surgery were randomized after completion of surgery to either an isocapnic hyperpnoea (IH) or a conventional recovery (C) group. The anaesthesia protocol included propofol, fentanyl, morphine, rocuronium and isoflurane in air/O2. Groups were compared using unpaired t‐test and ANOVA.

Results: Minute ventilation in the IH group before extubation was 22.6±2.7 vs. 6.3±1.8 l/min in the C group. Compared with C, the IH group had a shorter time to extubation (5.4±2.7 vs. 15.8±2.7 min, P<0.01), initiation of spontaneous ventilation (2.7±2.3 vs. 6.5±4.5 min, P<0.01), BIS recovery >75 (3.2±2.3 vs. 8.9±5.8 min, P<0.01), eye opening (4.6±2.9 vs. 13.6±7.1 min, P<0.01) and eligibility for leaving the operating room (7.1±2.9 vs. 19.9±11.9 min, P<0.01). There was no difference in time for eligibility for PACU discharge.

Conclusion: Increasing alveolar ventilation enhances anaesthetic elimination and accelerates short‐term recovery in obese patients.
Use of acid suppressive therapy more than 10 years after the endoscopic diagnosis of reflux esophagitis with specific emphasis to trademark and generic proton pump inhibitors
Authors: Dackus Gwen HE , Loffeld Susan MLA , Loffeld Ruud JLF
Published: July 2011

Background and Aim:  Reflux esophagitis needs maintenance therapy. Data on comparison between trademark and generic medications are not available. Complaints and use of acid‐suppressive therapy 10 years after diagnosis were determined.

Methods:  A total of 672 patients with esophagitis between 1998 and 2000 were reviewed. Patients received a questionnaire regarding the use of acid‐suppressive therapy, dosage, compliance and satisfaction. The use of trademark and generic medications was assessed. The presence of reflux complaints was assessed via a questionnaire, and a symptom score was calculated using a five‐point Likert scale.

Results:  A total of 208 patients returned the questionnaire, of whom 161 (78%) used acid‐suppressive therapy. Of the patients still on therapy, 72% (n = 116, group 1) had reflux complaints, while the remaining 45 patients (28%, group 2) were in remission. There was no difference in sex, age, or severity of the initially diagnosed reflux esophagitis. Patients in group 1 were significantly less compliant and satisfied compared to patients from group 2 (73% vs 96% and 83% vs 100%, P < 0.001, respectively). An equal number of patients in both groups used trademark and generic medications (P = not significant). The presence of reflux complaints, as well as the symptom score, showed no difference between users of trademark or generic medication.

Conclusion:  More than 10 years after the diagnosis, 22% of patients stopped using acid‐suppressive therapy. Only a minority (28%) were in clinical remission, associated with significantly higher satisfaction and compliance to therapy, as compared to their symptomatic counterparts. There was no difference in effect and usage of trademark versus generic medication preparations.
Life expectancy of Chinese patients with chronic kidney disease without dialysis
Authors: SZETO CHEUK‐CHUN , KWAN BONNIE CHING‐HA , CHOW KAI‐MING , PANG WING‐FAI , KWONG VICKIE WAI‐KI , LEUNG CHI‐BON , LI PHILIP KAM‐TAO
Published: July 2011

Aim:  Long term dialysis is life‐saving for patients with end stage renal disease (ESRD). However, in ESRD patients with multiple comorbid conditions, dialysis may actually be futile, and conservative management is advisable. We studied the life expectancy of Chinese ESRD patients treated conservatively.

Methods:  We reviewed 63 consecutive ESRD patients who were treated conservatively in our centre. Duration of survival was calculated from the date of initial assessment for dialysis, as well as the expected date of needing dialysis based on previous trend of renal function decline.

Results:  At the end of the observation period, 55 patients died. Twelve patients died before the expected date of needing dialysis because of unrelated reasons, while 36 deaths were directly attributed to uraemia. The median overall survival after initial assessment for dialysis was 41.3 months (95% confidence interval (CI), 33.2 to 49.4 months). The median overall survival was 6.58 months (inter‐quartile range, 0.92 to 9.33 months) from the theoretical date of needing dialysis. The survival from the theoretical date of needing dialysis did not correlate with patient age, sex, diabetic status, or baseline renal function.

Conclusions:  In Chinese ESRD patients treated conservatively, the median survival is around 6 months after the theoretical date of needing dialysis. Our result provides an important piece of information for the decision of dialysis and patient counselling.
Influence of obesity on tumour volume in patients with prostate cancer
Authors: Capitanio Umberto , Suardi Nazareno , Briganti Alberto , Gallina Andrea , Abdollah Firas , Lughezzani Giovanni , Salonia Andrea , Freschi Massimo , Montorsi Francesco
Published: July 2011

Study Type – Prognosis (individual cohort)

Level of Evidence 2b

What's known on the subject? and What does the study add?

Obesity is associated with more aggressive prostate cancer.

Prostate cancer tumour volume is affected by excess weight, after adjustment for all possible clinical and pathological confounders.

OBJECTIVE

To investigate the association between body mass index and tumour volume at radical prostatectomy in a large European population.

PATIENTS AND METHODS

Recent data support the hypothesis that the hormonal environment in overweight and obese men may alter androgen‐dependent prostate growth. Body mass index (BMI) has been implicated in prostate cancer pathophysiology.

We analysed 1275 patients with prostate cancer who underwent radical prostatectomy at a single tertiary care institution. Mean tumour volume (TV) was evaluated according to BMI WHO categories (normal <25 kg/m2 vs overweight 25–30 kg/m2 vs obese 30–35 kg/m2 vs severely obese >35 kg/m2).

Univariable linear regression analyses targeted the association between BMI and TV at radical prostatectomy. Multivariable analyses were adjusted for age, prostate‐specific antigen value, biopsy Gleason sum, clinical stage and prostate volume.

RESULTS

Mean BMI was 26.3 kg/m2 (median 26; range 16.7–42.0). Mean TV was 5.6 mL (median 3.3; range 0.1–61.2). The mean prostate‐specific antigen value was 10.3 ng/dL (median 6.6; range 0.3–327).

The mean TV was 5.0, 5.8, 6.3 and 9.2 mL in normal, overweight, obese and severely obese patients, respectively (P= 0.03). TVs in men with a normal BMI were 84% smaller than in severely obese men (5.0 vs 9.2 mL).

On univariable analysis, BMI was correlated with TV at radical prostatectomy (P < 0.001). On multivariable analysis, BMI reached the independent predictor status after adjustment for age, prostate‐specific antigen value, biopsy Gleason score, clinical stage and prostate volume (P= 0.03).

CONCLUSION

We showed that BMI is independently associated with prostate cancer volume at radical prostatectomy. The present results confirm that obesity may play a key role in prostate cancer pathophysiology.
Poverty Effects of Higher Food Prices: A Global Perspective
Authors: de Hoyos Rafael E. , Medvedev Denis
Published: July 2011

The spike in international food prices between 2005 and the first half of 2008 drew much attention to the vulnerability of the poor to such shocks. This paper provides a formal assessment of the direct and indirect impacts of higher prices of agricultural goods on global poverty using a representative sample of 63–93% of the developing world's population. To assess the direct effects, the paper uses domestic food price data between January 2005 and December 2007—when the relative price of food staples rose by an average of 5.6%—to find that the number of individuals living under the extreme poverty line increased by 155 million, with almost three‐quarters of this increase taking place in East Asia. To take the second‐order effects into account, the paper links household survey data with a global general equilibrium model, finding that the same increase in consumer prices of agricultural goods (modeled by increasing demand for first‐generation biofuels) would raise the number of individuals living under extreme poverty by 32 million, with nearly the entire increase occurring in South Asia and Sub‐Saharan Africa.
Home Bias, Border Effect and Internal Market Integration in China: Evidence from Inter‐provincial Value‐added Tax Statistics
Authors: Xing Weibo , Li Shantong
Published: July 2011

This paper examines the home bias in regional trade and the integration of the internal market in China using inter‐provincial value‐added tax statistics. The administrative border between regions is an important trade barrier that results in home bias. Using a border effect model, we find evidence of home bias in provincial trade and relatively low border effects in domestic‐products trade in China. Moreover, the multilateral resistance model, based on a microeconomic foundation, also has strong power in explaining border effects in provincial trade. The empirical results imply that in accordance with some developed economies, China's market integration appears to have reached a high level.
Three Faces of Civilization: ‘In the Beginning All the World was Ireland’
Authors: van Krieken Robert
Published: July 2011

This paper outlines a refinement of the sociological usage of the concept ‘civilization’ by distinguishing between three different ‘faces’ of civilization – as the opposite of barbarism, as equivalent to culture, and in Elias's sense as capturing a particular trajectory of socio-historical development. I then illustrate how this distinction between three different faces of civilization can be deployed in relation to the history of the various attempts by the English to civilize the population of Ireland. Finally, I reflect on the centrality of the experience of the colonization of Ireland for the English conception of how ‘barbarism’ should be understood and opposed to ‘civilization’ (which was then later mobilized in the colonization of the New World), as well as on the ways in which the colonization of Ireland constituted a binding together of both civilizing and decivilizing processes.
How Civilizing Processes Continued: Towards an Informalization of Manners and a Third Nature Personality
Authors: Wouters Cas
Published: July 2011

Based on an analysis of manners books in four Western countries since 1890, this paper describes how ‘civilizing processes’ have continued in the nineteenth and twentieth centuries. The paper first focuses on three central functions of a ‘good society’ and its code of manners, and then describes how, in a long-term phase of formalizing manners and disciplining people, ‘dangerous’ emotions such as those related to physical (including sexual) violence came to be controlled in increasingly automatic ways. Thus, a second-nature or conscience-dominated type of personality became dominant. The twentieth century saw rising social constraints towards being unconstrained, and yet reflective, flexible, and alert. These pressures coincided with an informalization of manners and an emancipation of emotions: emotions that had been denied and repressed regained access to consciousness and wider acceptance in social codes. Yet it has been only since the ‘Expressive Revolution’ of the 1960s that standards of self-control have increasingly enabled people to admit, to themselves and others, to having ‘dangerous’ emotions without provoking shame, particularly the shame-fear of losing control and face. To the extent that it has become ‘natural’ to perceive the pulls and pushes of both ‘first nature’ and ‘second nature’, as well as the dangers and chances, short-term and long-term, of any particular situation or relation, a ‘third nature’ type of personality has been developing. Examples illustrating this trend also help us to understand it as a process of psychic integration triggered by continued social integration.
A Land of a Hundred Thousand Welcomes? Understanding Established and Outsiders Relations in Ireland
Authors: Loyal Steven
Published: July 2011

This paper examines the discriminatory and exclusionary treatment experienced by migrants in Ireland. After outlining the tremendous socio-economic changes that have taken place in the country, it discusses the rise of ethno-racial discrimination in Ireland before examining how these discriminatory and exclusionary practices have so far been interpreted largely within a post-structuralist frame of reference. After outlining the problems inherent in this literature, the paper examines how applicable an Eliasian established–outsider framework is for explaining these exclusionary processes whilst simultaneously noting the differences between Elias's Winston Parva study and the Irish situation.
Left ventricle enlargement and increased systolic velocity in the mitral valve are indirect markers of the hepatopulmonary syndrome
Authors: Pouriki Sophia , Alexopoulou Alexandra , Chrysochoou Christina , Raftopoulos Leonidas , Papatheodoridis George , Stefanadis Christodoulos , Pectasides Dimitrios
Published: July 2011

Background and aims: Hepatopulmonary syndrome (HPS) has been associated with left atrial enlargement, but the presence of other markers of left and right diastolic and/or systolic cardiac dysfunction has not been clarified. We prospectively evaluated the possible associations between echocardiographical‐Doppler findings and HPS.

Methods: Seventy‐nine cirrhotic patients without endogenous heart or pulmonary disease were included. HPS was diagnosed by the presence of increased arterial–alveolar‐difference and intrapulmonary right‐to‐left shunt at contrast‐enhanced transthoracic echocardiography. Echocardiographical systolic and diastolic indices, tissue Doppler imaging (TDI) of mitral and tricuspid annular motion and M‐mode echocardiography measurements were recorded.

Results: Hepatopulmonary syndrome was diagnosed in 12 (15.2%) patients. Patients with compared with those without HPS had significantly younger age, albumin levels and saturation of oxygen (SaO2) in an erect position, but higher left ventricular end diastolic diameter (LVEDD), ejection fraction, E‐wave peak velocity of tricuspid valve, left atrial volume, TDI E wave (early diastolic period) at the right free wall/tricuspid annulus (cm/s) and TDI S wave (systolic) at the left lateral wall/mitral annulus (TDI Smv). In multivariate analysis, the presence of HPS was found to be independently associated with younger age (P=0.027), lower SaO2 in an erect position (P=0.023), higher LVEDD (P=0.019) and higher TDI Smv (P=0.026). LVEDD and TDI Smv offered good diagnostic accuracy for HPS diagnosis (AUROC/c‐statistic: 0.724 and 0.736 respectively).

Conclusions: We confirmed that in patients with cirrhosis, the development of HPS is associated with higher cardiac output and hyperdynamic circulation. Left ventricle enlargement and higher systolic velocity in the mitral valve represent satisfactory indirect markers of HPS.
Three-Dimensional Fluid Dynamic Model for the Prediction of Microfiltration Membrane Fouling and Flux Decline
Authors: Ham Seounghyun , Kapoor Shiv G. , DeVor Richard E. , Wentz John E.
Published: July 2011

A three-dimensional fluid dynamic model is developed to predict flux decline due to membrane fouling during the microfiltration of semisynthetic metalworking fluids. The model includes surface forces as well as hydrodynamic effects. Two pore model geometries are developed based on sintered aluminum oxide membranes. Simulations conducted using a single-pathway pore geometry illustrate the ability of the three-dimensional model to represent how flow continues through a partially blocked pore and how partial blocking reduces effective cross-sectional area. A four-disk pore geometry is used to compare flux decline behavior for different pore size distributions representing a new membrane and a membrane that had become partially blocked. Flux decline results are found to be consistent with published experimental results for similar membranes. An example shows how the three-dimensional fluid dynamic model may be used to determine the best membrane pore size distribution for a given situation and therefore demonstrates its overall utility as a design tool.
Perceptual weighting of the envelope and fine structure across frequency bands for sentence intelligibility: Effect of interruption at the syllabic-rate and periodic-rate of speech
Authors: Fogerty Daniel
Published: July 2011

Listeners often only have fragments of speech available to understand the intended message due to competing background noise. In order to maximize successful speech recognition, listeners must allocate their perceptual resources to the most informative acoustic properties. The speech signal contains temporally-varying acoustics in the envelope and fine structure that are present across the frequency spectrum. Understanding how listeners perceptually weigh these acoustic properties in different frequency regions during interrupted speech is essential for the design of assistive listening devices. This study measured the perceptual weighting of young normal-hearing listeners for the envelope and fine structure in each of three frequency bands for interrupted sentence materials. Perceptual weights were obtained during interruption at the syllabic rate (i.e., 4 Hz) and the periodic rate (i.e., 128 Hz) of speech. Potential interruption interactions with fundamental frequency information were investigated by shifting the natural pitch contour higher relative to the interruption rate. The availability of each acoustic property was varied independently by adding noise at different levels. Perceptual weights were determined by correlating a listener’s performance with the availability of each acoustic property on a trial-by-trial basis. Results demonstrated similar relative weights across the interruption conditions, with emphasis on the envelope in high-frequencies.
Resonance blocking and passing effects in two-dimensional elastic waveguides with obstacles
Authors: Glushkov Evgeny , Glushkova Natalia , Golub Mikhail , Eremin Artem
Published: July 2011

Resonance localization of wave energy in two-dimensional (2D) waveguides with obstacles, known as a trapped mode effect, results in blocking of wave propagation. This effect is closely connected with the allocation of natural resonance poles in the complex frequency plane, which are in fact the spectral points of the related boundary value problem. With several obstacles the number of poles increases in parallel with the number of defects. The location of the poles in the complex frequency plane depends on the defect’s relative position, but the gaps of transmission coefficient plots generally remain in the same frequency ranges as for every single obstacle separately. This property gives a possibility to extend gap bands by a properly selected combination of various scatterers. On the other hand, a resonance wave passing in narrow bands associated with the poles is also observed. Thus, while a resonance response of a single obstacle works as a blocker, the waveguide with several obstacles becomes opened in narrow vicinities of nearly real spectral poles, just as it is known for one-dimensional (1D) waveguides with a finite number of periodic scatterers. In the present paper the blocking and passing effects are analyzed based on a semi-analytical model for wave propagation in a 2D elastic layer with cracks or rigid inclusions.
Perception of musical and lexical tones by Taiwanese-speaking musicians
Authors: Lee Chao-Yang , Lee Yuh-Fang , Shr Chia-Lin
Published: July 2011

This study explored the relationship between music and speech by examining absolute pitch and lexical tone perception. Taiwanese-speaking musicians were asked to identify musical tones without a reference pitch and multispeaker Taiwanese level tones without acoustic cues typically present for speaker normalization. The results showed that a high percentage of the participants (65% with an exact match required and 81% with one-semitone errors allowed) possessed absolute pitch, as measured by the musical tone identification task. A negative correlation was found between occurrence of absolute pitch and age of onset of musical training, suggesting that the acquisition of absolute pitch resembles the acquisition of speech. The participants were able to identify multispeaker Taiwanese level tones with above-chance accuracy, even though the acoustic cues typically present for speaker normalization were not available in the stimuli. No correlations were found between the performance in musical tone identification and the performance in Taiwanese tone identification. Potential reasons for the lack of association between the two tasks are discussed.
Shock pattern solutions for viscous-collisional plasma ion acoustic waves in view of the linear theory of the non-equilibrium thermodynamics
Authors: Abourabia Aly M. , Shahein Rabab A.
Published: July 2011

In the framework of irreversible thermodynamics, we study nonlinear ion-acoustic waves (IAWs) in viscous and collisional plasmas. Electrons, which form the background, are assumed to be nonthermal. On account of ion viscosity and ion-electron collisions, we investigate using ion fluid equations. We study the effects of the nonthermally distributed electrons β and the temperature ratio σ (= Ti/Te) on the stability, where the stability for Burger’s equation is analyzed by two methods: the phase portrait method and irreversible thermodynamics relations at different values of σ and β. We usa a reductive perturbation technique, where the nonlinear evolution of an IAW is governed by the driven Burger equation. This equation is solved exactly by using two methods: the tanh-function method and the Cole–Hopf transformation. Both methods produce shock wave solutions, their results compared, and good agreement exists in most predictions. The analytical calculations show that an IAW propagates as a shock wave with subsonic speed. The flow velocity, pressure, number density, electrostatic potential, and thermodynamic characteristics are estimated and illustrated as functions of time t and the distance x. It is found via the tanh-function method that the amplitudes of the sought-for functions of the system are suppressed and move towards an equilibrium state at the highest value of β. The tanh-function method reveals an advantage over the Cole–Hopf method in the viscous and collisional cases of IAWs, where it satisfies the stability conditions at the highest value of β with the chosen σ values when applied to evaluate the Onsager relation.
Energies and Auger widths of the high-lying double-excited states for Be-like neon
Authors: Zhuo Lin , Gou Bing-Cong , Wang Feng
Published: July 2011

Energies and Auger widths of high-lying doubly-excited states 1s23lnl′ (n = 3–6) for Be-like neon are calculated using a saddle-point variational method and saddle-point complex-rotation method. The relativistic corrections and mass polarization are obtained with first-order perturbation theory. The configuration structure of the high-lying doubly-excited series is checked by relativistic perturbation corrections. The oscillator strengths and radiative transition probabilities are also calculated. Our results of energies and Auger widths are compared with the available theoretical results in the literature. Auger channel energies are compared with those from high-resolution electron spectroscopy. Excellent agreement is obtained in each state.
The apparent velocity and acceleration of relativistically moving objects
Authors: Berlet Austen , McKeon Dennis G.C. , Chishtie Farrukh , Houde Martin
Published: July 2011

Although special relativity limits the actual velocity of a particle to the velocity of light, c, the observed velocity need not be the same as the actual velocity, as the observer is only aware of the position of a particle at the time in the past when it emitted the detected signal. We consider the apparent speed and acceleration of a particle in two cases, one when the particle is moving with a constant speed and the other when it is moving with a constant acceleration. One curious feature of our results is that in both cases, if the actual velocity of the particle approaches c, then the apparent velocity approaches infinity when it is moving toward the observer and c/2 when it is moving away from the observer.
Empirical Modeling of Metal-Contact Effects on Graphene Field-Effect Transistors
Authors: Nouchi Ryo , Tanigaki Katsumi
Published: July 2011

An empirical model is developed to characterize metal-contact effects on the transfer characteristics of graphene field-effect transistors. The present model is based on a diffusive transport, and considers charge carrier doping from metallic electrodes to the adjacent graphene channel. An electron–hole conductivity asymmetry, one of the main features in the transfer characteristics, is well reproduced by the model. Model calculations with varied parameters show that the conductivity asymmetry becomes more distinct with higher charge-carrier mobility, higher doping level at the metal contacts, larger extent of the doped region near the contacts, or shorter channel lengths.
Resistive Switching in Al/Graphene Oxide/Al Structure
Authors: Panin Gennady N. , Kapitanova Olesya O. , Lee Sang Wuk , Baranov Andrey N. , Kang Tae Won
Published: July 2011

We report resistive switching behaviors in an Al/graphene oxide/Al planar structure. Graphene oxide was synthesized by a modified Hummer's method from graphite rods. The planar structures were fabricated on a Si/SiO2 substrate by spin-coating graphene oxide suspensions and patterning Al electrodes by photolithography. Both diode-like (rectifying) and resistor-like (nonrectifying) behaviors were observed in the device switching characteristics. Electrical characterization of the Al/graphene oxide interface using the induced current identified a potential barrier near the interface and its spatial modulation, caused by local changes of resistance at a bias voltage, which correlated well with the resistive switching of the whole structure. The mechanism of the observed local resistance changes near the electrode and the associated resistive switching of the entire structure is associated with the electrodiffusion of oxygen and the formation of sp2 graphene clusters in an sp3 insulating graphene oxide layer formed near the electrode by a pre-forming process.
Room Temperature Logic Inverter on Epitaxial Graphene-on-Silicon Device
Authors: Moutaouakil Amine El , Kang Hyun-Chul , Handa Hiroyuki , Fukidome Hirokazu , Suemitsu Tetsuya , Sano Eiichi , Suemitsu Maki , Otsuji Taiichi
Published: July 2011

The inverting operation of a logic inverter, using two back-gate epitaxial graphene-on-silicon field-effect transistors (GOSFETs), is demonstrated at room temperature. Thanks to the asymmetric ambipolarity of the fabricated GOSFETs, owing to the undesirable back-gate leakage, the on/off state current has been dramatically reduced. This results in a well matched input/output voltage levels for a wide V
DD range from more than 1 V down to 0.5 V. The inverting operation of the device is obtained at as low V
DD bias as 0.5 V. Voltage gains higher than the unity are also obtained. The experimental results are in good agreement with the simulation results made for the case of asymmetric ambipolar transistors.
Characteristics of p–i–n Terahertz and Infrared Photodiodes Based on Multiple Graphene Layer Structures
Authors: Ryzhii Maxim , Otsuji Taiichi , Mitin Vladimir , Ryzhii Victor
Published: July 2011

We calculate the responsivity and dark-current-limited detectivity of terahertz and infrared interband detectors based on p–i–n junctions in the multiple graphene layer structures proposed recently. It is demonstrated that the interband tunneling can be an essential limiting mechanism of the ultimate values of detectivity. To achieve the ultimate detectivity, the optimization of the device structure and the proper choice of the temperature and the bias voltage are required. We show that owing to high values of the quantum efficiency and relatively low rates of thermogeneration, the detectors under consideration can exhibit high responsivity and detectivity at elevated temperatures (in particular, at room temperature) in a wide radiation spectrum and can substantially surpass other detectors.
Silicon Thin Film Powder Samples for Electron Spin Resonance Investigation: Role of Substrate and Preparation Procedure
Authors: Xiao Lihong , Astakhov Oleksandr , Finger Friedhelm
Published: July 2011

Different methods to prepare powder samples of amorphous and microcrystalline thin film silicon material deposited on glass and metal substrates for application in electron spin resonance (ESR) experiments are compared. The powder is needed to provide sufficient sample mass for ESR experiments which otherwise suffer from low signal-to-noise ratio for thin film silicon material deposited on glass with thickness of typically 1 µm and spin densities of less than 1016 cm-3, all in view of the geometrical constraints of ESR cavities. As temporary substrates, Al and Mo foils and glass covered with ZnO are used and we compare the influences of the different substrates, the removal procedure and the exposure time to the etchant or ambient on the ESR properties of the silicon films. We describe reliable sample preparation and annealing procedures under which all three temporary substrates yield very similar ESR properties for the different silicon materials.
Bias-Temperature- and Light-Induced Instability in Short-Channel (L = 1.5 µm) p-Type Polycrystalline Silicon Thin-Film Transistors on Glass Substrates
Authors: Choi Sung-Hwan , Han Min-Koo
Published: July 2011

We investigated the electrical al characteristics of laser-crystallized polycrystalline silicon thin-film transistors (poly-Si TFTs) under various stresses, such as bias, temperature, and light illumination. The threshold voltage of the short-channel TFTs (L
CH = 1.5 µm) was significantly shifted in the negative direction owing to bias temperature stress (ΔV
TH = -3.75 V) compared with that found in long-channel TFTs (ΔV
TH = -0.32 V) at 100 °C. We also investigated the effects of light illumination on laser-crystallized poly-Si TFTs. In order to improve the reliability of laser-crystallized poly-Si TFTs, we developed a multiple-channel structure fabricated without using any additional processes.
Electrical Characterization of Terphenyl-Based Molecular Devices
Authors: Goto Touichiro , Inokawa Hiroshi , Ono Yukinori , Fujiwara Akira , Torimitsu Keiichi
Published: July 2011

The electrical characteristics of phenylene-based molecular devices were assessed. The device consisted of nanogap electrodes and phenylene-based conjugated molecules. One nanogap electrode was obtained by the electromigration of a Au nanowire modified with a self-assembled monolayer (SAM) of 4,4-p-terphenyldithiol (TPDT). The other nanogap electrode was fabricated by the shadow evaporation of metals and subsequent deposition of SAM. Some devices obtained by the electromigration of Au nanowire modified with SAMs exhibited a large activation energy of electrical conduction of up to 0.26 eV. This large activation energy coincides with the intramolecular barrier estimated by ab initio molecular orbital calculations. On the other hand, the devices composed of shadow evaporated nanogaps and subsequently deposited TPDT exhibited a comparatively small activation energy. Neither device showed a clear gate effect with an electrical field up to 3 MV/cm. These results indicate that the electrical characteristics of molecular devices are affected by the fabrication process and the resultant molecule-electrode configuration.
Wavelength-Selective Routing of Optical Short Pulses with Weighted Collinear Acoustooptic Devices
Authors: Goto Nobuo , Miyazaki Yasumitsu
Published: July 2011

Wavelength-selective processing of optical high-bit-rate wavelength-division-multiplexed (WDM) pulses is a key function in photonic networks. Collinear acoustooptic (AO) devices have potential for wavelength-selective routing of optical WDM short pulses. The wavelength selectivity, however, affects the transmission characteristics as the pulse period becomes short, resulting in distortion of the optical pulse shape. Pulse distortion through routing with weighted collinear AO devices is discussed. As weighted AO devices, we consider a sidelobe-suppressed AO device and a Butterworth-type AO device. The pulse distortion characteristics are numerically analyzed using Fourier transformation and the coupled mode theory. Our results show that pulse distortion for pulses having the bandwidths of 40, 160, and 320 GHz can be small for a sidelobe-suppressed AO device having an interaction length less than 20, 10, and 5 mm, respectively. With the Butterworth-type AO device, the interaction length can be 40, 20, and 10 mm for 40, 160, and 320 GHz pulses, respectively.
Slope Efficiency Improvement in Mode-Hop Driven Tunable Single-Mode Cholesteric Liquid Crystal Laser
Authors: Inoue Yo , Yoshida Hiroyuki , Inoue Kenta , Kumagai Takayuki , Kubo Hitoshi , Fujii Akihiko , Ozaki Masanori
Published: July 2011

We report the improvement in the slope efficiency of tunable single-mode cholesteric liquid crystal (ChLC) lasers with a three-layered structure. The device consists of one photopolymerized ChLC layer with a wide reflection band, another ChLC layer with a notch reflection band, and a rhodamine-6G-doped ionic liquid layer acting as the gain medium. Single-mode lasing is obtained from this device structure because the ChLC layer with the notch reflection band strongly reflects only one of the Fabry–Perot cavity modes, and the mode-hop-driven tuning of the lasing wavelength is possible because the reflection band of the notch ChLC can be tuned using external stimuli, such as heat. Our device showed a maximum slope efficiency of 16% (considering emission only in the forward direction), and was found to be approximately 1.5 times larger than that of ordinary ChLC lasers doped with the pyrromethene 597 laser dye. The improvement in the slope efficiency is believed to be attributed to the high quantum efficiency of the rhodamine 6G dye, which cannot be used in conventional ChLC lasers because of its low solubility, but can be used in our device because of the isotropic gain medium employed.
Location and Density Control of Carbon Nanotubes Synthesized Using Ferritin Molecules
Authors: Hanasaki Itsuo , Tanaka Toshihiro , Isono Yoshitada , Zheng Bin , Uraoka Yukiharu , Yamashita Ichiro
Published: July 2011

We have developed the process to control the location and density of carbon nanotubes (CNTs). The CNTs were synthesized by thermal chemical vapor deposition (CVD) using acetylene and hydrogen gas with an aid of iron catalyst particles contained in ferritin molecules. The adsorption pattern of ferritin molecules was produced by the liftoff process to control the domain for CNTs. Baking process after the ferritin coating was crucial to keep the high adsorption density of ferritin after the liftoff process. The higher density of CNTs was obtained by the higher flow rate of acetylene gas. Furthermore, the control of ferritin adsorption density by the alternate multistep coating process has enabled even higher density of CNTs.
Oxidation Resistance of Ti–Si–N and Ti–Al–Si–N Films Deposited by Reactive Sputtering Using Alloy Targets
Authors: Takahashi Kousuke , Oka Nobuto , Yamaguchi Maho , Seino Yutaka , Hattori Koichiro , Nakamura Shin-ichi , Sato Yasushi , Shigesato Yuzo
Published: July 2011

Ti–Si–N and Ti–Al–Si–N films, which possess high hardness due to the formation of a nanocomposite structure in the films, were deposited by reactive magnetron sputtering using alloy targets and then postannealed in air at temperatures ranging from 300 to 800 °C. The hardness of both the films decreased significantly as postannealing temperature increased. However, the hardness of Ti–Al–Si–N films postannealed up to 500 °C remained at more than 30 GPa, which was significantly higher than that of the Ti–Si–N films after the post annealings. Electron probe microanalyses and X-ray photoelectron spectroscopy revealed that Al2O3 phases were formed in the postannealed Ti–Al–Si–N films. Transmission electron microscopy with energy-dispersive X-ray analysis showed that the Al2O3 layer of the postannealed Ti–Al–Si–N films was formed 40 nm below the surface, whereas the depth of the TiO2–SiO2 layer of the postannealed Ti–Si–N films was 100 nm from the surface. These results indicate that Al2O3 phases existed at the surface of the Ti–Al–Si–N films and prevented the oxidation of the interior of the films during postannealing at high temperatures in air.
Effect of Acid Generator Decomposition during Exposure on Acid Image Quality of Chemically Amplified Extreme Ultraviolet Resists
Authors: Kozawa Takahiro , Tagawa Seiichi
Published: July 2011

In chemically amplified extreme ultraviolet (EUV) resists, acid generators are mainly sensitized through the reaction with thermalized electrons. The resolution blur (the migration range of thermalized electrons) and quantum efficiency depend on the acid generator concentration. Therefore, the decomposition of acid generators during exposure affects both resolution blur and quantum efficiency. In this study, the effect of acid generator decomposition on the acid image quality was investigated by Monte Carlo simulation. It was found that the degradation of acid image contrast caused by acid generator decomposition increases with a reduction in feature sizes. Independently of the contrast in the EUV aerial image, the acid image contrast was similarly degraded with the increase of exposure dose. The effect of flare on the additional contrast degradation caused by acid generator decomposition during exposure was also estimated. For the suppression of this flare effect, it is important to increase the acid generator concentration.
Noncontact Optical Brain Activity Measurement System Using Phosphor Placed on Skin
Authors: Funane Tsukasa , Atsumori Hirokazu , Suzuki Atsushi , Kiguchi Masashi
Published: July 2011

A noncontact brain activity measurement system using phosphor [Li(Nd0.9Yb0.1)P4O12] which is excited by and emits near-infrared light was developed. To optimize and validate this system, first, the influence of fluorescence lifetime on the amplitude of lock-in detection was investigated to determine the optimal frequency of the light source's intensity modulation. Second, the sensitivity of the system to the internal absorbance change was estimated using a phantom measurement. Third, to clearly show that this system can detect the absorbance changes in the cerebral blood instead of those in the superficial regions, the hemoglobin changes in the same area of the prefrontal cortex were measured during a working memory task by simultaneously using this system and a conventional contact optical topography system. Finally, the precision of the system was evaluated. The results verified that this system was as effective as a conventional system in detecting human brain activity.
Nanoimprint Fabrication and Thermal Behavior of Atomically Ultrasmooth Glass Substrates with 0.2-nm-Height Steps
Authors: Miyake Yumiko , Akita Yasuyuki , Oi Hideo , Mita Masahiro , Kaneko Satoru , Koyama Kohji , Sunagawa Kazuhiko , Tada Kazuhiro , Hirai Yoshihiko , Yoshimoto Mamoru
Published: July 2011

We examined the conditions for the development of atomically stepped ultrasmooth surfaces on commercial silicate glass substrates by the thermal nanoimprint technique using sapphire (α-Al2O3 single crystal) molds with 0.2-nm-height atomic steps. Under the pressing conditions of 3 MPa, 300 s, and 610 °C for imprinting, a 0.2-nm-high stepped and atomically ultrasmooth terraced surface could be formed on soda-lime silicate glass substrates having the glass transition temperature of 521 °C. We found that the 0.2-nm-height step structure of the imprinted glass surface disappeared after annealing at 490 °C, and the smoothness of the terrace increased.
Minute Mechanical-Excitation Wave-Front Propagation in Human Myocardial Tissue
Authors: Kanai Hiroshi , Tanaka Motonao
Published: July 2011

Complexity of the cardiac contraction sequence is still not fully understood because the dynamic mechanical excitation process, which directly correlates with contraction, cannot be accurately measured based on the electro-magnetic phenomena. By developing a noninvasive novel imaging modality with high temporal and spatial resolutions, the present study shows that the propagation of the mechanical wave-front occurs at the beginning of cardiac contraction sequence for the first time (about 60 ms prior to the ordinarily accepted onset time of the contraction). From the apical side of the interventricular septum, a minute velocity component with an amplitude of several tenth micrometers is generated and it propagates from the apex to the base of the posterior wall, and then from the base to the apex of the septum, with a propagation speed of 3–9 m/s. This dynamic measurement modality is also applicable to various tissues in biology.
Nondestructive Evaluation of Weld Defect by Photoacoustic Microscopy and Its Destructive Inspection Using Replica
Authors: Kato Ryosuke , Endoh Haruo , Hoshimiya Tsutomu
Published: July 2011

The nondestructive evaluation (NDE) of a surface crack and an internal defect introduced in the welded region of an aluminum plate has been demonstrated by photoacoustic microscopy. The surface crack and internal defect are a blowhole and an incomplete fusion, which were formed in the weld metal during welding. Experiments were carried out at different modulation frequencies. Furthermore, to gather information on the internal defect, the measurement of the size and shape of the weld defect was carried out by the replica technique. A stereoscopic image of the replica specimen was compared with a photoacoustic (PA) amplitude image.
High-Power Piezoelectric Characteristics at Continuous Driving of Bi4Ti3O12–SrBi4Ti4O15-Based Ferroelectric Ceramics
Authors: Noumura Yoji , Hiruma Yuji , Nagata Hajime , Takenaka Tadashi
Published: July 2011

The high-power piezoelectric characteristics at continuous driving were studied on lead-free piezoelectric ceramics of a mixed bismuth layer-structured ferroelectric, Bi4Ti3O12–SrBi4Ti4O15 (abbreviated as BIT–SBTi) with MnCO3-doping (abbreviated as BIT–SBTi + Mn x wt %). MnCO3-doping to BIT–SBTi can improve its high-power piezoelectric properties such as the mechanical quality factor Q
m. The vibration velocity, v
0–p, of the BIT–SBTi + Mn 0.2 wt % ceramics was above 2.0 m/s at 5 V/mm in the case of short- and long-time driving. Also, we observed that the resonance frequency change and temperature on the sample surface at a long-time driving for BIT–SBTi + Mn 0.2 wt % were less than 1.0% and 50 °C at v
0–p of 2.0 m/s, respectively. The high-power characteristics of BIT–SBTi + Mn x wt % were superior to those of hard Pb(Zr,Ti)O3 (abbreviated as PZT) at a vibration velocity v
0–p > 1.0 m/s. Therefore, Mn-doped BIT–SBTi-based ceramics are a promising candidate for lead-free high-power applications requiring frequency stability and long-time driving.
Characterization of LiNbO3 Single-Crystal Substrates Irradiated with Electrons
Authors: Miyazaki Hisashi , Morimoto Jun , Toda Kohji , Onoda Shinobu , Ohshima Takeshi
Published: July 2011

Electron irradiation effects on lithium niobate (LiNbO3) single crystals have been investigated by photoacoustic spectroscopy (PAS), Fourier transform infrared (FT-IR) spectroscopy, and Raman scattering spectroscopy. The photoacoustic signal intensity at 750 nm increase with increasing electron electron fluence. The OH- absorption spectra in the IR region are used to examine the defect structure of LiNbO3. The absorption spectra are almost the same at electron fluencies below 5 ×1017/cm2. We found that the influence of the electron irradiation was different between the mirror-polished side and the as-sliced side, as determined from the Raman spectra. There was no change in the Raman spectra on the mirror-polished LiNbO3 surface side. The control of the composition is most important to avoid the effects of electron irradiation.
Breathing-Mode Ceramic Element for Therapeutic Array Transducer
Authors: Otsu Kenji , Yoshizawa Shin , Umemura Shin-ichiro
Published: July 2011

A new concept of piezoceramic array transducer element using breathing mode has been proposed for therapeutic application. Finite element numerical simulation showed that a concave hemispherical piezoceramic shell with a diameter slightly larger than the wavelength in water is effective for obtaining good acoustic matching with water. A hemispherical piezoceramic element with an inner diameter of 4.0 mm and a thickness of 0.2–0.4 mm produced more than several times higher acoustic power output than a conventional thickness-mode element at the same drive voltage in the simulation. Its good acoustic matching with water is considered to be accomplished by the combined resonance with the spherical bulk of water half covered by the shell, because the resonance was very sensitive to the change in sound speed of the virtual material replacing water with the same acoustic impedance in simulation.
Construction of Acceleration Sensor Using a Coupled Vibrator
Authors: Terada Jiro , Sugawara Sumio , Mito Yoshikazu
Published: July 2011

We describe an acceleration sensor comprised of a detection structure constructed from a pair of adjacent vibration bars with resonance frequencies closely aligned to the drive resonance and which are connected to, and placed in opposite directions from each other, in the load direction. Using this structure, acceleration can be easily calculated by differential detection of the oscillation amplitude signals of each of the two vibration bars. The volume of the sensor is made of stainless steel (SUS304). The volume of the experimental sample is about 80×90×8 mm3, and the resonance frequency and quality factor are about 770 Hz and 145, respectively. The sensor characteristics are measured using the gravitational field, and the acceleration is changed by rotating the sensor around the axis along the length of the vibrator.
Visualization of Thermal Distribution Caused by Focused Ultrasound Field in an Agar Phantom
Authors: Kim Jungsoon , Kim Moojoon , Ha Kanglyeol
Published: July 2011

Ultrasound waves have been widely used not only in medical diagnostic systems but also in medical treatment. There has been increasing interest in the thermal distribution caused by ultrasound waves. In this study, using thermochromic particles, a visualization method was suggested in a mimic phantom for organic materials. By blending various thermochromic particles with different critical temperatures, the thermal field distribution in the phantom could be observed. The effect of a concave-type ultrasound transducer on the temperature distribution in an agar phantom mixed with thermochromic particles was observed. The temperature distribution corresponded to changes in the brightness distribution of gray. It was confirmed that the thermal distribution pattern in the vicinity of the focal area varies with the time exposure to ultrasound waves.