bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Process for Hydrothermal Lead-Free Piezoelectric Powders and Performances of Sintered (K0.48Na0.52)NbO3 Ceramics
Authors: Maeda Takafumi , Hemsel Tobias , Morita Takeshi
Published: July 2011

In this study, we report some improvements in a hydrothermal method for lead-free piezoelectric powders and the performance of the sintered (K0.48Na0.52)NbO3 ceramics. To increase the obtained powder weight per source solution volume, the hydrothermal reaction conditions were modified. This improvement is important for mass production; however, it resulted in a larger particle size dispersion. Therefore, we examined to introduced the ball milling process that is useful for dense (K0.48Na0.52)NbO3 ceramics. When a large amount of powder was obtained, it took a long time to eliminate the residual alkaline ions in the hydrothermal powders by a washing process. Therefore, a neutralization was conducted in the powder washing process. Using this powder, a solid solution of (K,Na)NbO3 ceramics was synthesized. The relative density was successfully increased. Concerning the electrical properties, the relative permittivity was improved, and the piezoelectric constant d
33 was also increased from 114 to 130 pC/N.
Noncontact Monitoring of Surface Temperature Distribution by Laser Ultrasound Scanning
Authors: Yamada Hiroyuki , Kosugi Akira , Ihara Ikuo
Published: July 2011

A laser ultrasound scanning method for measuring a surface temperature distribution of a heated material is presented. An experiment using an aluminum plate heated up to 120 °C is carried out to verify the feasibility of the proposed method. A series of one-dimensional surface acoustic wave (SAW) measurements within an area of a square on the aluminum surface are performed by scanning a pulsed laser for generating SAW using a galvanometer system, where the SAWs are detected at a fixed location on the surface. An inverse analysis is then applied to SAW data to determine the surface temperature distribution in a certain direction. The two-dimensional distribution of the surface temperature in the square is constructed by combining the one-dimensional surface temperature distributions obtained within the square. The surface temperature distributions obtained by the proposed method almost agrees with those obtained using an infrared radiation camera.
Tomographic Measurement of Vortex Air Flow Field Using Multichannel Transmission and Reception of Coded Acoustic Wave Signals
Authors: Li Haiyue , Takata Syogo , Yamada Akira
Published: July 2011

An acoustic travel time tomography system for the monitoring of the vortex wind flow velocity profile has been studied, where multichannel parallel acoustic transmitter/receiver pairs are placed along opposite sides of the monitoring region. Thus far, to prevent cross-talk between the elements, travel time collections must be made successively for every single transducer element. Hence, it is difficult to achieve real-time observation while maintaining the temporal variation in the air flow field. To realize simultaneous multichannel travel time collections, a coded modulation method is introduced using the Kasami sequence. To verify the validity of the method, basic examinations of both simulation and experiment data are carried out.
Examination on Fast Algorithms of Compact Finite Difference Calculation for Finite Difference Time Domain Acoustic Wave Simulation
Authors: Yoda Takeshi , Okubo Kan , Tagawa Norio , Tsuchiya Takao
Published: July 2011

In this study we examined a fast and efficient calculation method for compact finite-differences (FDs). The proposed method employs a recursive filter (RF) method. This method is based on z-transformation and its RF algorithm. Analysis of sound propagation using compact FDs with the RF method was implemented. Using the RF algorithm, we can implement compact finite difference time domain (FD-TD) analysis as a simpler code than a conventional technique using LU factorization, i.e., the Tomas method. The results obtained in this study clarified that the RF method reduces calculation time required for compact FDs.
Detection of Shear Horizontal Guided Waves Propagating in Aluminum Plate with Thinning Region
Authors: Nakamura Nurmalia , Ogi Hirotsugu , Hirao Masahiko
Published: July 2011

We propose a new method for wall-thinning inspection based on mode conversion of shear horizontal (SH) guided waves, which is represented as group velocity change. Group velocities of higher modes of SH guided wave propagating in a plate-like wave guide depend on the thickness and frequency due to dispersive characteristic. There exists a cut-off thickness for each higher mode, below which the associated mode cannot propagate and mode conversion to lower ones is expected, leading to discontinuous velocity change. Here, the fundamental SH0 and first asymmetric SH1 modes are generated by the periodic-permanent-magnet electromagnetic acoustic transducer (PPM-EMAT) and propagated in aluminum plates containing thinning regions. A broad-range piezoelectric pinducer is used to detect the propagating wave in order to explore the mode conversions phenomena. We directly observed that the generated SH1 mode converts to SH0 mode in thinning region and converts back to SH1 mode when the thickness returns to original.
Optimal Design of Lamb Wave Electromagnetic Acoustic Transducers for Improving Their Excitation Performance
Authors: Kang Lei , Wang Shujuan , Jiang Tao , Zhai Guofu
Published: July 2011

An optimal design method for improving the excitation performance of the Lamb wave electromagnetic acoustic transducers (EMATs) is proposed to minimize the influence of multi-mode and dispersion and to increase the signal strength of Lamb waves concurrently. The method combines the “two-intersection-points” method and “zero-slope” criterion with the orthogonal test method. Nine prime parameters of Lamb wave EMATs are optimized and the influences of parameters on Lamb wave signal strength are obtained. Analysis indicates that the spacing interval of the coil and the working frequency of the transducers determine multi-mode and dispersion characteristics of Lamb waves, and lift-off distance, excitation current, magnet thickness and conductor width play a significant role in the signal strength. Experimentation shows that, after optimization, not only are the multi-mode and dispersion phenomena of Lamb waves minimized, but also the signal amplitude is increased by 216%, which verifies the validity of the proposed method.
High-Frequency Electrodeless Quartz Crystal Microbalance Chip with a Bare Quartz Resonator Encapsulated in a Silicon Microchannel
Authors: Kato Fumihito , Ogi Hirotsugu , Yanagida Taiji , Nishikawa Shintaro , Nishiyama Masayoshi , Hirao Masahiko
Published: July 2011

We present a high-frequency electrodeless quartz crystal microbalance (QCM) chip with a bare quartz resonator encapsulated in a silicon microchannel, which is fabricated by micromachining technology. This QCM chip packages an AT-cut quartz plate 2.5 mm long, 1.7 mm wide, and 9.6 µm thick, which is supported by micropillars without fixed parts. There is no issue about destruction during assembly because handling the fragile quartz resonator becomes unnecessary. The quartz resonator is electrodeless and not fixed; therefore, there are no losses due to electrodes and contacting wires. As a result, a high quality factor (Q-factor) and a high signal-to-noise ratio (SNR) can be obtained. The Q-factor is about 800–2800 at 170 MHz in the flow of the carrier solution. In addition, it is possible to reuse the device, because the quartz surfaces can adsorb receptor proteins nonspecifically, which can be removed by a washing procedure with a strong acid solution flowed in the microchannel. The high-frequency quartz resonator (170 MHz) encapsulated in the microchannel can reduce the influence of the viscosity contribution to the frequency shift, achieving highly sensitive and quantitative analysis. The QCM chip is excited and detects the shear vibrations of the quartz resonator by the line antennas without contact. Consequently, both sides of the quartz resonator can be used as the detection area in a solution. We succeeded in detecting the human immunoglobulin G (hIgG) at a concentration of 6 µg/ml via the staphylococcal protein A (SPA) immobilized nonspecifically on the developed QCM chip in real time without any labeling.
Sensitivity Analysis of Lateral Field Excited Acoustic Wave Gas Sensors with Finite Element Method
Authors: Chen Yung-Yu , Liu Chih-Chieh
Published: July 2011

In the last decade, there are increasing investigations on lateral field excited (LFE) acoustic wave sensors in biochemical liquid sensing applications due to their high sensitivity and simple fabrication. However, the research on this kind of sensor for gas detection is still awaited. This paper presents a theoretical modeling of the LFE acoustic wave gas sensor with a nanostrustured selective film for the first time. We developed this model by adopting a finite element software, COMSOL. Besides the eigenfrequency and frequency-response analyses, the sensitivities to the variations of mass density and electrical conductivity of the selective film caused from gas concentration were calculated. In the meantime, quartz crystal microbalance (QCM) sensors were also analyzed for comparison. Finally, the effect of geometry of the LFE gas sensor on the sensitivity was discussed. Results show that the LFE sensor exhibits larger sensing range and higher sensitivity to external electrical variation than the QCM sensor. This is because no shielding electrode exists on sensing surface of the LFE sensor, and hence the electric field can penetrate into the selective film. The simulation results provide useful guidelines for designing LFE acoustic wave gas sensors.
Zero Temperature Coefficient of Frequency Surface Acoustic Wave Resonator for Narrow-Duplex-Gap Application on SiO2/Al/LiNbO3 Structure
Authors: Nakanishi Hidekazu , Nakamura Hiroyuki , Tsurunari Tetsuya , Fujiwara Joji , Hamaoka Yosuke , Hashimoto Ken-ya
Published: July 2011

In this paper, we describe a zero temperature coefficient of frequency (TCF) surface acoustic wave (SAW) resonator on a SiO2/Al/LiNbO3 structure. We studied the dependence of TCF and electromechanical coupling factor (K
2) of shear-horizontal (SH) SAW on SiO2 thickness, where the SiO2 shape control technique is applied to suppress spurious responses caused by the Rayleigh mode. As a result, we could realize a high performance SAW resonator having moderate K
2 (8%) and zero TCF with complete suppression of the Rayleigh-mode spurious response. We demonstrated that the SiO2 shape control technique is effective for suppression of the Rayleigh-mode spurious response in the SAW resonator using the SiO2/Al/LiNbO3 structure for a wide range of SiO2 thicknesses. We also revealed the applicability of the SiO2/Al/LiNbO3 structure to SAW duplexers with a narrow duplex gap.
Measurement of the Resonant Characteristics of a Single Bubble Vibration by Using a Laser Doppler Vibrometer
Authors: Yoshikawa Taisuke , Kotera Hironori , Yoshida Kenji , Koyama Daisuke , Nakamura Kentaro , Watanabe Yoshiaki
Published: July 2011

We constructed the experimental system with a laser Doppler vibrometer (LDV) for measuring the vibration of a single microbubble. It was demonstrated that the system enabled the capture of the vibration with an amplitude of nanometer order. We attempted to experimentally measure the resonant characteristics of a bubble attached to a wall by using the system. As a result, we succeeded in measuring the characteristics and evaluating the Q factor and the resonant radius at a driving frequency of 27.8 kHz, although these values are different from those predicted on the basis of the theory for a single free bubble. The LDV measurement system is expected to an effective tool for evaluating bubble vibrations with very small displacement amplitudes, such as the vibration of a microcapsule.
Sonophotocatalytic Destruction of Chloroform: Comparison of Processes and Synergistic Effects
Authors: Park Beomguk , Cho Eunju , Park Heedeung , Khim Jeehyeong
Published: July 2011

This study compared ultrasound, ultraviolet, and catalyst processes and evaluated their respective synergistic effects. The ultrasonic frequencies in this study used 35, 283, 450, and 935 kHz, whereas short wavelength ultraviolet lamp (UVC) was used. The dose of TiO2 was 0.3 g/L. The degradation rate constants for the sonophotolytic processes were (4.2–8.7)×10-3 min-1, nearly the same for the sonolytic processes. The value of the synergistic effect was 1.07. The main mechanism of this process was pyrolysis by ultrasound. The ultraviolet provided another mechanism as using oxidation by hydroxyl radicals, but the enhancement was not significant. The rate constants of sonophotocatalytic processes were (48.1–64.6)×10-3 min-1. The calculated value of synergistic effect was 1.54. In this process, the main mechanism for degradation was oxidation by hydroxyl radicals on the surface of TiO2. The roles of the ultrasound were the dispersion of catalyst and mass transport of pollutant to the surface of the catalyst.
Finite Element Analysis of the Standing Wave Field in a Tube with Lossy Wall for Thermoacoustic System
Authors: Nishikori Michiaki , Tsuchiya Takao , Sakamoto Shin-ichi
Published: July 2011

The finite element method (FEM) is applied to the analysis of the steady-state sound field in a thermoacoustic tube in the frequency domain. Although the thermoacoustic field is nonlinear and isothermal, a linear and adiabatic model is proposed, in which only the sound intensity field is considered because the sound intensity is generally discussed for the efficiency of energy conversion in the thermoacoustic system. In the numerical model, the divergence of the sound intensity is modeled as the sound source and the dissipation is modeled as loss caused by the specific acoustic impedance of the wall. Some numerical demonstrations are made for the two-dimensional standing wave field in a straight tube with a lossy wall. The influences of the stack and the phase adjuster on the sound field are examined. It is found that the sound field in the thermoacoustic tube can be qualitatively analyzed by introducing the specific acoustic impedance of the wall.
Development and Characterization of a Small Ring-Shaped Ultrasonic Probe for Biopsies
Authors: Tanaka Yuusuke , Tanaka Katsuhiko , Sugiyama Susumu , Kurumi Yoshimasa , Tani Tohru , Nishitani Yutaka , Takahashi Osamu
Published: July 2011

A small ultrasonic probe capable of precise control of needle position is required for biopsies taken in abdominal surgery and laparoscopic surgery. We fabricated a small size ring-shaped probe with a through hole to insert the needle. The probe simultaneously detects the object in front of it, e.g., a lesion, and the tip of the needle. The error of the insertion depth measured by this detection was estimated to be less than 10.1% at a depth of more than 5 mm when the inner diameter of the probe was 1.1 mm and the outer diameter of the needle was 0.6 mm. The results of an experiment using a stomach wall specimen indicate that the position of the needle can be precisely controlled because the needle is directly below the probe.
Multi Element Diverging Beam from a Linear Array Transducer for Transverse Cross Sectional Imaging of Carotid Artery: Simulations and Phantom Vessel Validation
Authors: Ponnle Akinlolu , Hasegawa Hideyuki , Kanai Hiroshi
Published: July 2011

Transverse cross sectional imaging of the intima–media complex of the carotid arterial wall is difficult to obtain by conventional linear scanning. The angular widths of imaged regions of the anterior and posterior walls are limited. In this study, multi element diverging beam from a linear array transducer was investigated by simulations and experiments. B-mode image was reconstructed, using combinations of multi angle receiving beams from multiple transmissions per frame. The images obtained by the proposed method from simulations and silicone-rubber tube phantom showed an increase in the angular width over that in the case of conventional linear scanning. Also, images were investigated for sub aperture sizes of 36, 56, and 96 elements with different beam-spread angles. On the basis of the results of the present study, the sub aperture size of 36 elements and beam-spread angle of 90° are recommended for achieving the optimum results for this application in in-vivo imaging.
Effect of Existence of Red Blood Cells in Trapping Performance of Microbubbles by Acoustic Radiation Force
Authors: Masuda Kohji , Nakamoto Ryusuke , Watarai Nobuyuki , Koda Ren , Taguchi Yuto , Kozuka Teruyuki , Miyamoto Yoshitaka , Kakimoto Takashi , Enosawa Shin , Chiba Toshio
Published: July 2011

We have proposed a method to control microbubbles by making use of acoustic radiation force, which is generated with acoustic propagation, to correspond to therapeutic applications of ultrasound. By preventing bubbles from passing through the desired target area, the local concentration of bubbles can be enhanced. However, we have never experimentally confirmed this phenomenon under in vivo conditions or close to those. Thus, we carried out an experiment to evaluate the trapping performance of bubbles using a suspension of red blood cells (RBCs) and an artificial blood vessel. By defining the trapping index to evaluate the amount of trapped microbubbles, we have confirmed that the trapping performance was enhanced according to the concentration of RBCs and the sound pressure, but not according to the central frequency of ultrasound. The results indicate that the existence of RBCs near microbubbles contributed to the increase in the size of aggregations propelled against the vessel wall.
Reference Materials for the Measurement of Acoustic Attenuation Coefficients
Authors: Yoshida Tomoji , Gotow Akari , Tanaka Kouhei , Kondo Toshio
Published: July 2011

In this work, we present a reference material for measuring the acoustic attenuation coefficient of biological tissues or tissue-mimicking materials by a transmission method. Accurate measurements by the method require a reference material that has the same acoustic velocity and density as the biological tissue. The newly developed reference material was prepared from NaCl and MgSO4 aqueous solutions. The inorganic material is stable through time. To formulate materials with the desired acoustic velocity and density, the ratio of three constituents (i.e., water, NaCl, and MgSO4) can be determined depending on the method of experiments with mixtures by Scheffe.
Automated Identification of the Heart Wall Throughout the Entire Cardiac Cycle Using Optimal Cardiac Phase for Extracted Features
Authors: Takahashi Hiroki , Hasegawa Hideyuki , Kanai Hiroshi
Published: July 2011

In most methods for evaluation of cardiac function based on echocardiography, the heart wall is currently identified manually by an operator. However, this task is very time-consuming and suffers from inter- and intraobserver variability. The present paper proposes a method that uses multiple features of ultrasonic echo signals for automated identification of the heart wall region throughout an entire cardiac cycle. In addition, the optimal cardiac phase to select a frame of interest, i.e., the frame for the initiation of tracking, was determined. The heart wall region at the frame of interest in this cardiac phase was identified by the expectation–maximization (EM) algorithm, and heart wall regions in the following frames were identified by tracking each point classified in the initial frame as the heart wall region using the phased tracking method. The results for two subjects indicate the feasibility of the proposed method in the longitudinal axis view of the heart.
Three-Dimensional Anisotropy of Ultrasonic Wave Velocity in Bovine Cortical Bone: Effects of Hydroxyapatite Crystallites Orientation and Microstructure
Authors: Nakatsuji Tomohiro , Yamamoto Kazufumi , Suga Daisuke , Yanagitani Takahiko , Matsukawa Mami , Yamazaki Kaoru , Matsuyama Yukihiro
Published: July 2011

The three-dimensional anisotropy of longitudinal wave velocity and the hydroxyapatite (HAp) crystallites orientation in bovine cortical bone were experimentally investigated in detail. Bovine cortical bone has two typical microstructures, plexiform and haversian. Two spherical specimens (diameter: 9 mm) were obtained from the anterior (plexiform) and posterior (haversian) parts of a 30-month-old bovine femur. The three-dimensional anisotropy of longitudinal wave velocity was measured using a conventional ultrasonic pulse system by rotating the spherical specimen in the axial–tangential (A–T), axial–radial (A–R), and radial–tangential (R–T) planes. The velocity clearly changed depending on the propagation direction in all the planes. In the A–T and A–R planes, the direction of the highest velocity was slightly inclined from the bone axis direction. Moreover, the results from the X-ray pole figure analysis indicated that there were small tilts in the HAp crystallites orientation. The tilts were similar to those of the highest velocity direction and there were good correlations between velocity and HAp crystallites orientation. However, a comparatively low correlation was found in the posterior part, which shows the stronger effects of bone microstructure. On the other hand, in the R–T plane, where small HAp crystallites oriented, a weak velocity anisotropy was found owing to the bone microstructure. Ultrasonic wave velocities depended on both HAp crystallites orientation and microstructure. The degrees of contribution of these factors varied owing to the position and propagation direction.
Vertical Coherence Measurements of Ambient Noise in Shallow Water off the East Coast of Korea
Authors: Cho Sungho , Choi Jee Woong
Published: July 2011

Measurements of the vertical coherence of ambient noise in shallow water off the east coast of Korea are presented. The noise was received by a 15-m-length vertical line array covering the water column from 96.5 to 111.5 m, which was deployed in waters 160 m deep. The level of the power spectral density for frequencies less than 300 Hz was relatively low, suggesting that the contribution of the shipping noise to the overall noise level was negligibly small. The results of the measured coherence imply that the noise field was fairly symmetrical about the horizontal but not isotropic. The vertical coherence of the wind-generated sea-surface noise is compared to theory, without the consideration of shipping noise. The comparison suggests that the primary source of ambient noise in the experimental site was wind-driven sea-surface noise. A small discrepancy is found in frequencies above approximately 3 kHz. Possible causes for this are discussed.
Intercarrier Interference Cancellation for Time-Reversed Orthogonal Frequency Division Multiplexing Systems
Authors: Lin Chundan , Zhang Wansong , Yoon Jong Rak , Park Jihyun
Published: July 2011

Time-reversed orthogonal frequency division multiplexing (OFDM) communications arouse much interest in the bandlimited underwater acoustic channel. In this paper, a time-reversed OFDM communication system combined with an intercarrier interference (ICI) self cancellation scheme is proposed to reduce the ICI due to carrier frequency offset. Simulation results demonstrate that time-reversed OFDM systems using the proposed scheme can effectively reduce ICI effects, increase the signal-to-noise ratio (SNR) with low computation complexity, and hence give rise to performance improvement.
A minor role for lipocalin 2 in high-fat diet-induced glucose intolerance
Authors: Jun Lucy S. , Siddall C. Parker , Rosen Evan D.
Published: July 2011

Adipose tissue controls energy homeostasis and systemic insulin sensitivity through the elaboration of a series of cytokines and hormones, collectively termed “adipokines.” We and others have identified Lcn2 as a novel adipokine, but its exact role in obesity-induced insulin resistance remains controversial. The aim of this study was to examine the metabolic phenotype of Lcn2−/− mice to clarify the role of Lcn2 in metabolism. Male and female Lcn2−/− and wild-type (WT) littermates were placed on either chow or high-fat diet (HFD) to characterize their metabolic phenotype. Studies included body weight and body composition, glucose and insulin tolerance tests, and adipokine expression studies in serum and in white adipose tissue (WAT). Neither chow nor HFD cohorts showed any differences in body weight or body composition. Chow-fed Lcn2−/− mice did not exhibit any difference in glucose homeostasis compared with WT mice. Fasting serum glucose levels were lower in the chow-fed Lcn2−/− mice, but this finding was not seen in the HFD cohort. Serum adiponectin, leptin, resistin, and RBP4 levels were not different between WT and Lcn2−/− on chow diet. HFD-fed male Lcn2−/− mice did display a small improvement in glucose tolerance, but no difference in insulin sensitivity was seen in either male or female Lcn2−/− mice on HFD. We conclude that the global ablation of Lcn2 has a minimal effect on obesity-associated glucose intolerance but does not appear to affect either age- or obesity-mediated insulin resistance in vivo.
Operational Transresistance Amplifier-Based Multiphase Sinusoidal Oscillators
Authors: Pandey Rajeshwari , Pandey Neeta , Bothra Mayank , Paul Sajal K.
Published: July 2011

Multiphase sinusoidal oscillator circuits are presented which utilize Operational Transresistance Amplifier (OTRA) as the active element. The first circuit producesnodd-phase oscillations of equal amplitudes and equally spaced in phase. The second circuit is capable of producingnodd- or even- phase oscillations equally spaced in phase. An alternative approach is discussed in the third circuit, which utilizes a single-phase tunable oscillator circuit which is used to inject signals into a phase shifter circuits. An automatic gain control (AGC) circuit has been implemented for the second and third circuit. The circuits are simple to realize and have a low component count. PSPICE simulations have been given to verify the theoretical analysis. The experimental outcome corroborates the theoretical propositions and simulated results.
Hedgehog Fights Back: Mechanisms of Acquired Resistance against Smoothened Antagonists
Authors: Metcalfe Ciara , de Sauvage Frederic J.
Published: July 2011

Acquired resistance to targeted therapies threatens the value of these otherwise very promising agents. The recent description of resistance to the Hedgehog pathway inhibitor vismodegib (GDC-0449) in a medulloblastoma patient who had a dramatic initial response has spurred efforts to understand potential mechanisms of drug resistance. Elucidating these mechanisms will play a significant role in informing strategies to overcome this meaningful limitation. Cancer Res; 71(15); 5057–61. ©2011 AACR.
Phytochemical Prospection and Modulation of Aminoglycoside Antibiotic Activity by Croton campestris A.
Authors: Matias E.F.F. , Santos K.K.A. , Almeida T.S. , Costa J.G.M. , Coutinho H.D.M.
Published: July 2011

Background:Escherichia coli is known to produce enterotoxins whose properties and role in diarrheal disease have been extensively investigated; besides, this bacterium is related to several extra-intestinal problems in the intensive care unit and in surgical wound infections. Some species of Staphylococcus are recognized as etiological agents of opportunistic infections in animals and humans. This study is the first test on the modulation of antibiotic activity by Croton campestris A. against multiresistant strains of E. coli and Staphylococcus aureus. Methods: In this study, the hexane and methanol extract of C. campestris A. was tested for antibacterial activity alone and in combination with aminoglycosides against bacterial strains. The synergy of the methanol and hexane extract was verified by microdilution method. Results: A synergistic effect of both extracts combined with the aminoglycosides was demonstrated. Conclusions: It is suggested that the extracts from C. campestris A. could be used as a source of natural product derived from this plant with resistance-modifying antibacterial activity, providing a new weapon against the problem of bacterial resistance to antibiotics.
Effect of Sublethal CO2 Laser Irradiation on Gene Expression of Streptococcus mutans Immobilized in a Biofilm
Authors: Sol A. , Feuerstein O. , Featherstone J.D.B. , Steinberg D.
Published: July 2011

Streptococcus mutans colonizing on tooth surfaces is one of the major causative agents of human dental caries. Despite numerous studies conducted on lasers and oral tissue interactions, little is known about the effect of laser energy on S. mutans gene expression in a biofilm form. The aim of this study was to investigate the effect of sublethal energies of CO2 laser on biofilm and gene expression of the oral bacteria S. mutans immobilized in biofilm. S. mutans biofilm was irradiated with CO2 laser. Vitality and construction of the biofilm were observed by confocal laser scanning microscopy and scanning electron microscopy. The effect of laser irradiation on gene expression was evaluated by DNA microarray. CO2 laser irradiation had a dose effect on the viability of S. mutans immobilized in biofilm. A nonsignificant lethal effect was observed at 31 J/cm2 while at higher energy of 70 and 144 J/cm2 an antibacterial effect was recorded. The mode of antibacterial action seems to be from the inner layers toward the outer layer of the biofilm, indicating the influence of the surface on the killing effect. At 31 J/cm2, microarray analysis indicated a moderate effect on S. mutans gene expression due to CO2 laser irradiation, mainly down-regulating genes related to bacterial stress response. In conclusion, laser irradiation at sublethal energy had an effect on gene expression of S. mutans.
Instrumental Activities of Daily Living Impairment Is Associated with Increased Amyloid Burden
Authors: Marshall Gad A. , Olson Lauren E. , Frey Meghan T. , Maye Jacqueline , Becker J. Alex , Rentz Dorene M. , Sperling Reisa A. , Johnson Keith A. ,   Alzheimer’s Disease Neuroimaging Initiative
Published: July 2011

Background/Aims: Instrumental activities of daily living (IADL) impairment in Alzheimer’s disease has been associated with global amyloid deposition in postmortem studies. We sought to determine whether IADL impairment is associated with increased cortical Pittsburgh Compound B (PiB) retention. Methods: Fifty-five subjects (19 normal older controls, NC, and 36 with mild cognitive impairment, MCI) underwent clinical assessments and dynamic PiB positron emission tomography imaging. Results: A linear multiple regression model showed that greater IADL impairment was associated with greater global PiB retention in all subjects (R2 = 0.40; unstandardized partial regression coefficient, β = 5.8; p = 0.0002) and in MCI subjects only (R2 = 0.28; β = 6.1; p = 0.003), but not in NC subjects only. Conclusion: These results suggest that daily functional impairment is related to greater amyloid burden in MCI.
The Efficacy of Licensed-Indication Use of Donepezil and Memantine Monotherapies for Treating Behavioural and Psychological Symptoms of Dementia in Patients with Alzheimer’s Disease: Systematic Review and Meta-Analysis
Authors: Lockhart I.A. , Orme M.E. , Mitchell S.A.
Published: July 2011

Background/Aims: Behavioural and psychological symptoms of dementia (BPSD) in Alzheimer’s disease (AD) greatly increase caregiver burden. The abilities of donepezil and memantine to manage BPSD within their licensed indications in AD were compared. Methods: A systematic review, random effects meta-analysis and Bucher indirect comparison were conducted. Results: Six randomised controlled studies (4 donepezil and 2 memantine) reported use within the licensed indication and had Neuropsychiatric Inventory (NPI) data suitable for meta-analysis. BPSD showed significant improvement with donepezil compared with placebo [weighted mean difference (WMD) in NPI –3.51, 95% confidence interval (CI) –5.75, –1.27], whereas this was not the case for memantine (WMD –1.65, 95% CI –4.78, 1.49). WMD in NPI for donepezil versus memantine favoured donepezil but was not statistically significant (–1.86, 95% CI –5.71, 1.99; p = 0.34). Conclusion: Within its licensed indication, donepezil is efficacious for the management of BPSD in AD compared with placebo.
On the Vertical Distribution of Mean Vertical Velocities in the Convective Regions during the Wet and Dry Spells of the Monsoon over Gadanki
Authors: Uma K. N. , Kumar K. Kishore , Shankar Das Siddarth , Rao T. N. , Satyanarayana T. M.
Published: July 2011

The Indian Mesosphere–Stratosphere–Troposphere (MST) radar observations of vertical distribution of mean vertical velocities w in convective regions during the wet and dry spells of the Indian summer monsoon over a tropical station at Gadanki, India (13.5°N, 79.2°E) are discussed. The composite w profile during the wet spell consistently shows a single peak at ~13 km whereas during the dry spell it shows two peaks, one at 5 km and another at 11–13 km. The characteristics of this altitudinal distribution in w are discussed in terms of background wind and thermal structure during both spells of the monsoon. Background w obtained from NCEP–NCAR reanalysis shows subsidence throughout the depth of the troposphere during the dry spell of the monsoon over Gadanki. Analysis of background wind and thermal structure clearly reveal that wind shear and temperature inversion in the midtroposphere are different in the dry spell compared to that of the wet spell, which may be the possible reason for the observed double-peak w structure during the dry spell of the monsoon. The present analysis for the first time brought out the distinct vertical distribution in w and the background meteorological conditions during the wet and dry spells of the monsoon over Gadanki, which may have implications in understanding the monsoon convective systems during the wet and dry spells of the Indian summer monsoon.
Beyond Identity: Incorporating System Reliability Information Into an Automated Combat Identification System
Authors: Neyedli Heather F. , Hollands Justin G. , Jamieson Greg A.
Published: July 2011

Objective: The aim of this study was to evaluate display formats for an automated combat identification (CID) aid.

Background: Verbally informing users of automation reliability improves reliance on automated CID systems. A display can provide reliability information in real time.

Method: We developed and tested four visual displays that showed both target identity and system reliability information. Display type (pie, random mesh) and display proximity (integrated, separated) of identity and reliability information were manipulated. In Experiment 1, participants used the displays while engaging targets in a simulated combat environment. In Experiment 2, participants briefly viewed still scenes from the simulation.

Results: Participants relied on the automation more appropriately with the integrated display than with the separated display. Participants using the random mesh display showed greater sensitivity than those using a pie chart. However, in Experiment 2, the sensitivity effects were limited to lower reliability levels.

Conclusion: The integrated display format and the random mesh display were the most effective displays tested.

Application: We recommend the use of the integrated format and a random mesh display to indicate identity and reliability information with an automated CID system.
Martial Virtue
Authors: Hart David K. , Hart David W. , Nesbit Rebecca
Published: July 2011

The changing nature of modern warfare and consistent problems with ethical lapses have created significant problems in the administration of the U.S. military. The authors propose reengaging civic humanism in the form of martial virtue as the basis of a new military ethic. A more civically engaged military will be better equipped to manage the complexity and demands of modern warfare and, more important, do so in a more ethically prudent manner. Furthermore, martial virtue provides a bridge for the peculiar disjunction between military and public administration as well as a common normative ground from which to proceed. After providing a brief theoretical context, the authors propose six basic principles of martial virtue, followed by a more pragmatic discussion of the practical implications of such an ethic in the U.S. military.
Experiences in the Face of Disasters
Authors: Henderson Tammy L. , Hildreth Gladys
Published: July 2011

The current collection contributes to our understanding of the stress experienced by and resilience of individuals and families in the aftermath of a disaster. We begin the collection with an article on two theories, vulnerability and social capital theory. These theories serve as tools to capture physical, social, and economic vulnerabilities as well as to determine how the dynamics of social networks interact when experiencing a disaster. The remaining authors of the current collection examined the experiences, stresses, and resilience of lower-income mothers, special education teachers, older adults, and families. Authors offer recommendations for disaster planning or future research.
Public Health Ethics, Legitimacy, and the Challenges of Industrial Wind Turbines: The Case of Ontario, Canada
Authors: Shain Martin
Published: July 2011

While industrial wind turbines (IWTs) clearly raise issues concerning threats to the health of a few in contrast to claimed health benefits to many, the trade-off has not been fully considered in a public health framework. This article reviews public health ethics justifications for the licensing and installation of IWTs. It concludes that the current methods used by government to evaluate licensing applications for IWTs do not meet most public health ethical criteria. Furthermore, these methods are contrary to widely held fundamental principles of administrative law and governmental legitimacy. A set of decision-making principles are suggested to address this situation that are derived from existing and emerging legal principles in Canada and elsewhere. These include the Precautionary Principle, the Least Impactful Means (Proportionality) Test, and the Neighbor Principle.
Leo Strauss and Arab Philosophy
Authors: Abbes Makram
Published: July 2011

This paper closely examines Strauss’ conception of “medieval Enlightenment”. It focuses on the central role that arab philosophy has played in the development of Strauss’s thought and discusses the validity of the uses he makes of it. It also emphasizes the interest of Strauss’s analyses as regards arab philosophy while drawing attention to the tensions they create. It claims that Strauss’ involvement in the quarrel between ancients and moderns aims at showing that medieval philosophy cannot be reduced simply to the effort to reconcile philosophy and religion. The ideas of some arab philosophers cropped up throughout Strauss’s philosophical development and determined his interpretation of maimonides and Plato as well as his stance in opposition to the moderns. however Strauss’s idea of the “medieval Enlightenment” remains fundamentally ambiguous. Is that Enlightenment supposed to be an argument for the preservation of faith alongside reason or does it rather express a kind of atheism or disguised materialism?
Islamology Comes to the Aid of Islamism
Authors: Ghalioun Burhan
Published: July 2011

This paper discusses the idea of an incompatibility between muslim beliefs and the demands of modernity. It claims that the idea of Islam as a religion that makes it difficult for muslim societies to bring about the changes necessary for their entry into modernity is fostering the rise of radical Islamism. Islamology as an academic discipline seems grounded on the idea that the explanatory models of the social sciences are not applicable to Islam: interpreting the history of muslim societies, both modern and classical, must of necessity involve a change in technique and method. Whereas chairs in Islamology are proliferating in universities, arab world specialists, historians, anthropologists, sociologists, political scientists, economists and demographers are almost abandoning the study of real living societies in favour of Islamic studies. Scholars are increasingly taken up with theology, religious history, interfaith conflicts, the relationship between dogma and modern values and ideas. The authors claims in favour of “getting rid” of this centrality of theological issues, in favour of a more secular analysis of the history and present state of muslim societies.
‘Searching for a Sleeping State’
Authors: Oussedik Fatma
Published: July 2011

This paper deals with the role and task of intellectual groups in current muslim societies, with a particular outlook on algeria. It discusses the social and educational impact of their action, and the internal and external limits to their action. democratization and arabization are considered as two dialectical poles of the ongoing process of modernization of those societies.
Challenges of metal recycling and an international covenant as possible instrument of a globally extended producer responsibility
Authors: Wilts Hennning , Bringezu Stefan , Bleischwitz Raimund , Lucas Rainer , Wittmer Dominic
Published: July 2011

As illustrated by the case studies of end-of-life vehicles and waste electric and electronic equipment, the approach of an extended producer responsibility is undermined by the exports of used and waste products. This fact causes severe deficits regarding circular flows, especially of critical raw materials such as platinum group metals. With regard to global recycling there seems to be a responsibility gap which leads somehow to open ends of waste flows and a loss or down-cycling of potential secondary resources. Existing product-orientated extended producer responsibility (EPR) approaches with mass-based recycling quotas do not create adequate incentives to supply waste materials containing precious metals to a high-quality recycling and should be amended by aspects of a material stewardship. The paper analyses incentive effects on EPR for the mentioned product groups and metals, resulting from existing regulations in Germany. It develops a proposal for an international covenant on metal recycling as a policy instrument for a governance-oriented framework to initiate systemic innovations along the complete value chain taking into account product group- and resource group-specific aspects on different spatial levels. It aims at the effective implementation of a central idea of EPR, the transition of a waste regime still focusing on safe disposal towards a sustainable management of resources for the complete lifecycle of products.
Spike Firing Pattern of Output Neurons of the Limulus Circadian Clock
Authors: Liu Jiahui S. , Passaglia Christopher L.
Published: July 2011

The lateral eyes of the horseshoe crab ( Limulus polyphemus) show a daily rhythm in visual sensitivity that is mediated by efferent nerve signals from a circadian clock in the crab’s brain. How these signals communicate circadian messages is not known for this or other animals. Here the authors describe in quantitative detail the spike firing pattern of clock output neurons in living horseshoe crabs and discuss its possible significance to clock organization and function. Efferent fiber spike trains were recorded extracellularly for several hours to days, and in some cases, the electroretinogram was simultaneously acquired to monitor eye sensitivity. Statistical features of single- and multifiber recordings were characterized via interval distribution, serial correlation, and power spectral analysis. The authors report that efferent feedback to the eyes has several scales of temporal structure, consisting of multicellular bursts of spikes that group into clusters and packets of clusters that repeat throughout the night and disappear during the day. Except near dusk and dawn, the bursts occur every 1 to 2 sec in clusters of 10 to 30 bursts separated by a minute or two of silence. Within a burst, each output neuron typically fires a single spike with a preferred order, and intervals between bursts and clusters are positively correlated in length. The authors also report that efferent activity is strongly modulated by light at night and that just a brief flash has lasting impact on clock output. The multilayered firing pattern is likely important for driving circadian rhythms in the eye and other target organs.
Wavelet Measurement Suggests Cause of Period Instability in Mammalian Circadian Neurons
Authors: Meeker Kirsten , Harang Richard , Webb Alexis B. , Welsh David K. , Doyle Francis J. , Bonnet Guillaume , Herzog Erik D. , Petzold Linda R.
Published: July 2011

Cells in the suprachiasmatic nucleus (SCN) display remarkable precision, while either physically or chemically decoupling these cells from each other leads to a dramatic increase in period-to-period variability. Where previous studies have classified cells as either arrhythmic or circadian, our wavelet analysis reveals that individual cells, when removed from network interactions, intermittently express circadian and/or longer infradian periods. We reproduce the characteristic period distribution of uncoupled SCN cells with a stochastic model of the uncoupled SCN cell near a bifurcation in Bmal1 transcription repression. This suggests that the uncoupled cells may be switching between 2 oscillatory mechanisms: the indirect negative feedback of protein complex PER-CRY on the expression of Per and Cry genes, and the negative feedback of CLOCK-BMAL1 on the expression of the Bmal1 gene. The model is particularly sensitive near this bifurcation point, with only a small change in Bmal1 transcription repression needed to switch from the stable precision of coupled SCN cells to the unstable oscillations of decoupled individual cells, making this rate constant, an ideal target for cell signaling in the SCN.
Acute Disseminated Encephalomyelitis Preceding Measles Exanthema
Authors: Nardone Raffaele , Golaszewski Stefan , Trinka Eugen , Tezzon Frediano , Zuccoli Giulio
Published: July 2011

We report a case of acute disseminated encephalomyelitis preceding measles virus infection. Brain magnetic resonance imaging revealed signal intensity abnormalities in the basal ganglia and cortex consistent with acute disseminated encephalomyelitis. Fever and the first Koplik spots appeared 8 and 10 days later, respectively. This case supports the hypothesis that the immune-mediated demyelinating process may occur before the symptomatic phase of a viral infection. Therefore, children without history of infectious disorders should also have acute disseminated encephalomyelitis included in the differential considerations.
Family Interventions to Prevent Maltreatment of Children With Disabilities
Authors: Weisleder Pedro
Published: July 2011

In addition to the challenges inherent to physical and cognitive impairments, children with disabilities are at high risk of exhibiting behavioral and emotional problems. Consequently, their parents are under undo stress, which in some instances may lead to child abuse. Specifically, children with disabilities are 3 to 4 times more likely to be abused than are their normally developing peers. This alarming statistic is a consequence of a set of interrelated factors that include the child, the disability, the family, and the socioeconomic environment where they live. In this installment of Ethical Crossroads, Murphy examines those factors. She ends her commentary by emphasizing the importance of recognizing the caregivers' needs. In her mind, patient-focused rehabilitation interventions fall short of the mark. Instead, providing support to the family unit is a more fitting approach to the multidisciplinary care of a child with disabilities.