bluuebunny/crossref_metadata_2025 huggingface dataset:
rtL180M mutation of hepatitis B virus is closely associated with frequent virological resistance to adefovir dipivoxil therapy
Authors: Lee Yoon‐Seon , Chung Young‐Hwa , Kim Jeong A , Jin Young Joo , Park Won Hyung , Kim Sung Eun , Lee Danbi , Shim Ju Hyun , Kim Kang Mo , Lim Young Suk , Lee Han Chu , Lee Yung Sang , Suh Dong Jin
Published: July 2011

Background and Aim:  We intended to investigate the effects of pre‐existing mutations at reverse transcriptase region of hepatitis B virus (HBV) on the occurrence of virological breakthrough (VB) to adefovir dipivoxil (ADV) in patients with lamivudine (LAM)‐resistant chronic hepatitis B (CHB).

Methods:  Ninety‐seven patients with LAM‐resistant CHB were treated with ADV at a dose of 10 mg daily, and were followed for a median period of 13 months. Just before the initiation of ADV therapy, the whole length of reverse transcriptase region of serum HBV‐DNA was sequenced using direct sequencing.

Results:  All patients had genotype C HBV and mutations in the YMDD motif, specifically, YIDD (65%), YVDD (28%), or both (7%). The rtL180M and rtL80V/I mutations were identified in 68% and 69%, respectively. The cumulative probability of VB was 19% and 27% at 1 and 2 years, respectively. There was no difference in the occurrence of VB with regard to types of YMDD mutation or rtL80V/I. However, interestingly, patients carrying rtL180M experienced VB during ADV monotherapy more frequently than those not carrying rtL180M (2‐year cumulative probability of VB: 37% vs 3% at 2 years, P < 0.01). On multivariate Cox proportional hazards analysis, rtL180M (hazard ratio [HR]: 8.62, 95% confidence interval: 1.08–69.09, P = 0.042) and decrease in HBV‐DNA for 1 year of treatment (HR: 0.69, 95% CI: 0.51–0.95, P = 0.024) are independently associated with VB.

Conclusions:  The rtL180M mutation of HBV, as well as a small decrease in HBV‐DNA after 1 year of treatment might be closely associated with frequent occurrence of virological resistance to ADV in patients with LAM‐resistant CHB.
Cenozoic mystery birds – on the phylogenetic affinities of bony‐toothed birds (Pelagornithidae)
Authors: Mayr Gerald
Published: July 2011

Mayr, G. (2011) Cenozoic mystery birds – on the phylogenetic affinities of bony‐toothed birds (Pelagornithidae). —Zoologica Scripta, 40, 448–467.

The extinct Cenozoic bony‐toothed birds (Pelagornithidae) are characterized by the occurrence of unique spiky projections of the osseous jaws and are among the most distinctive neornithine taxa. Earlier authors considered these marine birds to be most closely related to ‘Pelecaniformes’ or Procellariiformes, but recent phylogenetic analyses resulted in a sister group relationship to Anseriformes. This latter hypothesis was, however, coupled with a non‐monophyly of galloanserine or even neognathous birds, which is not supported by all other current analyses. The character evidence for anseriform affinities of pelagornithids is thus reassessed, and it is detailed that the alleged apomorphies cannot be upheld. Pelagornithids lack some key apomorphies of galloanserine birds, and analysis of 107 anatomical characters did not support anseriform affinities, but resulted in a sister group relationship between Pelagornithidae and Galloanseres. By retaining a monophyletic Galloanseres, this result is in better accordance with widely acknowledged hypotheses on the higher‐level phylogeny of birds. The (Pelagornithidae + Galloanseres) clade received, however, only weak bootstrap support, and some characters, such as the presence of an open frontoparietal suture, may even support a position of Pelagornithidae outside crown‐group Neognathae.
Handing over the Torch: Intergenerational Processes in Figurational Sociology
Authors: Gabriel Norman , Mennell Stephen
Published: July 2011

This collection of essays is designed to show how the various concepts of Norbert Elias's writings fit together in an overall vision for sociology, and how this has come to inspire the wide-ranging and interdisciplinary research tradition of ‘figurational’ sociology. In this introduction, we focus on a somewhat neglected aspect of Elias's work, the concept of generation. We explore his role as a teacher, passing the torch to a first generation of scholars, mainly in Europe, examining his generosity to younger colleagues as well as some of his well-known foibles. We then trace his influence in the emergence of a second generation that is more far-flung, both internationally and across disciplines.
Expression of the 2′,3′‐cAMP‐adenosine pathway in astrocytes and microglia
Authors: Verrier Jonathan D. , Exo Jennifer L. , Jackson Travis C. , Ren Jin , Gillespie Delbert G. , Dubey Raghvendra K. , Kochanek Patrick M. , Jackson Edwin K.
Published: July 2011

J. Neurochem. (2011) 118, 979–987.

Many organs express the extracellular 3′,5′‐cAMP‐adenosine pathway (conversion of extracellular 3′,5′‐cAMP to 5′‐AMP and 5′‐AMP to adenosine). Some organs release 2′,3′‐cAMP (isomer of 3′,5′‐cAMP) and convert extracellular 2′,3′‐cAMP to 2′‐ and 3′‐AMP and convert these AMPs to adenosine (extracellular 2′,3′‐cAMP‐adenosine pathway). As astrocytes and microglia are important participants in the response to brain injury and adenosine is an endogenous neuroprotectant, we investigated whether these extracellular cAMP‐adenosine pathways exist in these cell types. 2′,3′‐, 3′,5′‐cAMP, 5′‐, 3′‐, and 2′‐AMP were incubated with mouse primary astrocytes or primary microglia for 1 h and purine metabolites were measured in the medium by mass spectrometry. There was little evidence of a 3′,5′‐cAMP‐adenosine pathway in either astrocytes or microglia. In contrast, both cell types converted 2′,3′‐cAMP to 2′‐ and 3′‐AMP (with 2′‐AMP being the predominant product). Although both cell types converted 2′‐ and 3′‐AMP to adenosine, microglia were five‐ and sevenfold, respectively, more efficient than astrocytes in this regard. Inhibitor studies indicated that the conversion of 2′,3′‐cAMP to 2′‐AMP was mediated by a different ecto‐enzyme than that involved in the metabolism of 2′,3′‐cAMP to 3′‐AMP and that although CD73 mediates the conversion of 5′‐AMP to adenosine, an alternative ecto‐enzyme metabolizes 2′‐ or 3′‐AMP to adenosine.
Immunomodulatory effects of Alliums and Ipomoea batata extracts on lymphocytes and macrophages functions in White Leghorn chickens: In vitro study
Authors: HANIEH Hamza , NARABARA Kiyoaki , TANAKA Yuji , GU Zhigang , ABE Asaki , KONDO Yasuhiro
Published: July 2011

We previously described that supplementary garlic, onion and purple sweet potato (PSP) enhance humoral immune response in White Leghorn chickens. In the present in vitro study, we investigated the effects of garlic (GE), onion (OE) and PSP (PSPE) extracts on proliferation, interleukin (IL)‐2 and interferon (INF)‐γ gene expression of stimulated lymphocytes. The effects on microbicidal activity, reactive oxygen species (ROS) and nitric oxide (NO) productions of stimulated peritoneal macrophages were studied as well. The results showed that GE augmented Concanavalin A (ConA)‐induced splenocytes (4, 8 and 16 µg/mL) and thymocytes (2, 4 and 8 µg/mL) proliferations, and gene expression of IL‐2 (8 and 16 µg/mL) and INF‐γ (16 µg/mL). None of the examined extracts had mitogenic effect nor stimulated bursacytes response to phorbol 12‐myristate 13‐acetate (PMA). Macrophages exhibited superior microbicidal activity and ROS production with GE at 4 and 8 µg/mL and with OE at 25.6 µg/mL. None of the extracts showed stimulatory effects on NO production. The extracts showed concentration‐dependent inhibitory effects on all measured parameters at higher concentrations. Taken together, it is likely that garlic has direct stimulatory effects on immune cell functions, whereas the in vitro inhibitory effects of onion and PSP were likely attributed to high flavonoid contents.
The re-occurrence of mHz quasi-periodic oscillations in Cygnus X−3
Authors: Koljonen K. I. I. , Hannikainen D. C. , McCollough M. L.
Published: July 2011

We have re-analysed archival RXTE data of the X-ray binary Cygnus X−3 with a view to investigate the timing properties of the source. As compared to previous studies, we use an extensive sample of observations that include all the radio/X-ray spectral states that have been categorized in the source recently. In this study we identify two additional instances of quasi-periodic oscillations that have centroid frequencies in the mHz regime. These events are all associated to a certain extent with major radio flaring, which in turn is associated with relativistic jet ejection events. We review briefly scenarios whereby the quasi-periodic oscillations may arise.
1,2‐Bis(methylsulfonyl)‐1‐(2‐chloroethyl)‐2‐[[1‐(4‐nitrophenyl)ethoxy]carbonyl]hydrazine (KS119): a Cytotoxic Prodrug with Two Stable Conformations Differing in Biological and Physical Properties
Authors: Penketh Philip G. , Baumann Raymond P. , Shyam Krishnamurthy , Williamson Hugh S. , Ishiguro Kimiko , Zhu Rui , Eriksson Emma S. E. , Eriksson Leif A. , Sartorelli Alan C.
Published: July 2011

The anticancer prodrug 1,2‐bis(methylsulfonyl)‐1‐(2‐chloroethyl)‐2‐[[1‐(4‐nitrophenyl)ethoxy]carbonyl]hydrazine (KS119) selectively releases a short‐lived cytotoxin following enzymatic reduction in hypoxic environments found in solid tumors. KS119, in addition to two enantiomers, has two stable atropisomers (conformers differing in structure owing to hindered bond rotation) that interconvert at 37 °C in aqueous solution by first‐order kinetics with t1/2 values of ∼50 and ∼64 h. The atropisomers differ in physical properties such as partition coefficients that allow their chromatographic separation on non‐chiral columns. A striking difference in the rate of metabolism of the two atropisomers occurs in intact EMT6 murine mammary carcinoma cells under oxygen‐deficient conditions. A structurally related molecule, 1,2‐bis(methylsulfonyl)‐1‐(2‐chloroethyl)‐2‐[[1‐(3‐hydroxy‐4‐nitrophenyl)ethoxy]carbonyl]hydrazine (KS119WOH), was also found to exist in similar stable atropisomers. The ratio of the atropisomers of KS119 and structurally related agents has the potential to impact the bioavailability, activation, and therapeutic activity. Thus, thermally stable atropisomers/conformers in small molecules can result in chemically and enantiomerically pure compounds having differences in biological activities.
A proteomic approach to elucidate the multiple targets of selenium‐induced cell‐growth inhibition in human lung cancer
Authors: Zhong Xiaorong , Li Lu , Wang Min , Luo Wei , Tan Qingwei , Xu Feng , Zhu Wen , Wang Qi , Wang Ting , Hou Mei , Nadimity Nagalakshmi , Xue Xingyang , Chen Jun , Ma Wei , Gao Allen C. , Zhou Qinghua
Published: July 2011

Background:  Methylseleninic acid (MSA) has been implicated as a promising anticancer agent for lung cancer. However, the underlying molecular mechanism(s) responsible for MSA's action is not well understood. Our study aimed to examine the cellular effects of MSA on L9981 human high‐metastatic large cell lung cancer cells and gain insights into its possible molecular mechanism(s) through a proteomic approach.

Methods:  L9981 cells were exposed to MSA at different concentrations and time points. The effects of MSA on cell proliferation and apoptosis were detected by cell viability analyzer Vi‐CELL and flow cytometric analysis, respectively. We analyzed the alterations in the proteome profile of L9981 cells induced by MSA using the 2‐D difference in gel electrophoresis (2‐D DIGE) and identified the differentially expressed proteins using a liquid chromatography system followed by tandem mass spectrometry (LC‐MS/MS).

Results:  We found that MSA inhibited cell proliferation in a dose‐dependent manner and significantly induced early apoptosis in L9981 cells. 2‐D DIGE showed that MSA induced significant changes (>1.29 fold) in the expression levels of 42 protein spots compared to the untreated control (P < 0.05). As identified by LC‐MS/MS, proteins that underwent changes in response to MSA were related to various biological functions, including: (i) endoplasmic reticulum stress (upregulation of molecular chaperones like heat shock protein A5, protein disulfide‐isomerase precursor, and calreticulin precursor); (ii) oxidative stress response/ thioredoxin system (decreased thioredoxin‐like protein 1 and increased thioredoxin reductase 1); (iii) translation regulation (downregulation of translation factors like elongation factor 1‐beta and eukaryotic translation initiation factor 6); (iv) mitochondrial bioenergetic function (upregulation of adenosine triphosphate synthase subunit beta and mitochondria); and (v) cell signal transduction regulation (decreased peptidyl‐prolyl cis‐trans isomerase A and 14‐3‐3 protein gamma). The protein and gene expression levels of those proteins of interest were further confirmed by Western blot and/or real‐time reverse transcription polymerase chain reaction.

Conclusion:  Our results suggest that MSA may inhibit cell proliferation and induce apoptosis in lung cancer by modulating multiple targets involved in various crucial cellular processes.
Survival and Prognostic Indicators for Cycad Intoxication in Dogs
Authors: Ferguson D. , Crowe M. , McLaughlin L. , Gaschen F.
Published: July 2011

Background: Cycad palms are commonly used in landscaping and ingestion by dogs can cause disease or death.

Objectives: Determine the morbidity and case fatality of cycad palm toxicosis in dogs from Louisiana, and examine putative prognostic factors.

Animals: Thirty‐four client‐owned dogs with confirmed cycad palm toxicosis between 2003 and 2010.

Methods: Retrospective cohort study. Search of all medical records for animals with cycad palm toxicosis.

Results: Seventeen of 34 (50%) dogs died or were euthanized as a direct consequence of cycad intoxication. There were no differences in presenting signs and physical examination findings between survivors and nonsurvivors. Nonsurvivors had higher serum alanine transaminase activity (median 196 U/L; range 16–4,123 versus 113.5; 48–1,530) and total bilirubin concentration (0.5 mg/dL; 0.1–6.2 versus 0.25; 0–1.7) upon presentation, and their initial serum concentrations of albumin (2.9 g/dL; 1.4–4.1 versus 3.3; 2.2–3.9) were lower than those of survivors. Nadir serum albumin concentration was also lower in nonsurvivors (1.9; 1.4–3.7 versus 3.2; 1.8–3.5). A higher proportion of nonsurvivors had prolonged coagulation times, prothrombin time. and partial thromboplastin time. In a multivariate model, administration of charcoal at initial presentation was associated with longer survival (heart rate [HR] 0.019, 95% CI 0.001–0.644), while high serum aspartate aminotransferase activity was a negative prognostic factor (HR 118.2, 95% CI 2.89–4,826).

Conclusions and Clinical Importance: Cycad intoxication is associated with a higher case fatality than previously published. Several laboratory parameters might help differentiating potential nonsurvivors from survivors. Administration of charcoal as part of the emergency treatment appears to have a protective effect.
Characterization of the Dip Pen Nanolithography Process for Nanomanufacturing
Authors: Saha Sourabh K. , Culpepper Martin L.
Published: July 2011

Dip pen nanolithography (DPN) is a flexible nanofabrication process for creating 2-D nanoscale features on a surface using an “inked” tip. Although a variety of ink-surface combinations can be used for creating 2-D nanofeatures using DPN, the process has not yet been characterized for high throughput and high quality manufacturing. Therefore, at present it is not possible to (i) predict whether fabricating a part is feasible within the constraints of the desired rate and quality and (ii) select/design equipment appropriate for the desired manufacturing goals. Herein, we have quantified the processing rate, tool life, and feature quality for DPN line writing by linking these manufacturing metrics to the process/system parameters. Based on this characterization, we found that (i) due to theoretical and practical constraints of current technology, the processing rate cannot be increased beyond about 20 times the typical rate of ∼1 μm2/min, (ii) tool life for accurate line writing is limited to 1–5 min, and (iii) sensitivity of line width to process parameters decreases with an increase in the writing speed. Thus, we conclude that for a high throughput and high quality system, we need (i) parallelization or process modification to improve throughput and (ii) accurate fixtures for rapid tool change. We also conclude that process control at high speed writing is less stringent than at low speed writing, thereby suggesting that DPN has a niche in high speed writing of narrow lines.
The effects of age and cochlear hearing loss on temporal fine structure sensitivity, frequency selectivity, and speech reception in noise
Authors: Hopkins Kathryn , Moore Brian C. J.
Published: July 2011

Temporal fine structure (TFS) sensitivity, frequency selectivity, and speech reception in noise were measured for young normal-hearing (NHY), old normal-hearing (NHO), and hearing-impaired (HI) subjects. Two measures of TFS sensitivity were used: the “TFS-LF test” (interaural phase difference discrimination) and the “TFS2 test” (discrimination of harmonic and frequency-shifted tones). These measures were not significantly correlated with frequency selectivity (after partialing out the effect of audiometric threshold), suggesting that insensitivity to TFS cannot be wholly explained by a broadening of auditory filters. The results of the two tests of TFS sensitivity were significantly but modestly correlated, suggesting that performance of the tests may be partly influenced by different factors. The NHO group performed significantly more poorly than the NHY group for both measures of TFS sensitivity, but not frequency selectivity, suggesting that TFS sensitivity declines with age in the absence of elevated audiometric thresholds or broadened auditory filters. When the effect of mean audiometric threshold was partialed out, speech reception thresholds in modulated noise were correlated with TFS2 scores, but not measures of frequency selectivity or TFS-LF test scores, suggesting that a reduction in sensitivity to TFS can partly account for the speech perception difficulties experienced by hearing-impaired subjects.
A modal Wentzel-Kramers-Brillouin approach to calculating the waveguide invariant for non-ideal waveguides
Authors: Cockrell Kevin L. , Schmidt Henrik
Published: July 2011

The frequency dependence of a waveguide's Green's function can be summarized by a single parameter known as the waveguide invariant, β. Although it has been shown analytically that β≈1 for ideal waveguides, numerical and experimental results have shown that β≈1 for many realistic shallow water waveguides as well. There is not much prior work explaining why the non-uniformities present in realistic sound speed profiles sometimes have such a small effect on the value of β. This paper presents a method for calculating β using a modal Wentzel-Kramers-Brillouin (WKB) description of the acoustic field, which reveals a straightforward relationship between the sound speed profile and β. That relationship is used to illustrate why non-uniformities in the sound speed profile sometimes have such a small effect on β and under what circumstances the non-uniformities will have a large effect on β. The method uses implicit differentiation and thus does not explicitly solve for the horizontal wavenumbers of the modes, making it applicable to waveguides with arbitrary sound speed profiles and fluid bottom halfspaces. Several examples are given, including an analytic estimate of β in a Pekeris waveguide.
Benefit of temporal fine structure to speech perception in noise measured with controlled temporal envelopes
Authors: Eaves Joanne M. , Quentin Summerfield A. , Kitterick Pádraig T.
Published: July 2011

Previous studies have assessed the importance of temporal fine structure (TFS) for speech perception in noise by comparing the performance of normal-hearing listeners in two conditions. In one condition, the stimuli have useful information in both their temporal envelopes and their TFS. In the other condition, stimuli are vocoded and contain useful information only in their temporal envelopes. However, these studies have confounded differences in TFS with differences in the temporal envelope. The present study manipulated the analytic signal of stimuli to preserve the temporal envelope between conditions with different TFS. The inclusion of informative TFS improved speech-reception thresholds for sentences presented in steady and modulated noise, demonstrating that there are significant benefits of including informative TFS even when the temporal envelope is controlled. It is likely that the results of previous studies largely reflect the benefits of TFS, rather than uncontrolled effects of changes in the temporal envelope.
Learning a novel phonological contrast depends on interactions between individual differences and training paradigm design
Authors: Perrachione Tyler K. , Lee Jiyeon , Ha Louisa Y. Y. , Wong Patrick C. M.
Published: July 2011

Studies evaluating phonological contrast learning typically investigate either the predictiveness of specific pretraining aptitude measures or the efficacy of different instructional paradigms. However, little research considers how these factors interact—whether different students learn better from different types of instruction—and what the psychological basis for any interaction might be. The present study demonstrates that successfully learning a foreign-language phonological contrast for pitch depends on an interaction between individual differences in perceptual abilities and the design of the training paradigm. Training from stimuli with high acoustic-phonetic variability is generally thought to improve learning; however, we found high-variability training enhanced learning only for individuals with strong perceptual abilities. Learners with weaker perceptual abilities were actually impaired by high-variability training relative to a low-variability condition. A second experiment assessing variations on the high-variability training design determined that the property of this learning environment most detrimental to perceptually weak learners is the amount of trial-by-trial variability. Learners’ perceptual limitations can thus override the benefits of high-variability training where trial-by-trial variability in other irrelevant acoustic-phonetic features obfuscates access to the target feature. These results demonstrate the importance of considering individual differences in pretraining aptitudes when evaluating the efficacy of any speech training paradigm.
Toward optimizing stream fusion in multistream recognition of speech
Authors: Mesgarani Nima , Thomas Samuel , Hermansky Hynek
Published: July 2011

A multistream phoneme recognition framework is proposed based on forming streams from different spectrotemporal modulations of speech. Phoneme posterior probabilities were estimated from each stream separately and combined at the output level. A statistical model of the final estimated posterior probabilities is used to characterize the system performance. During the operation, the best fusion architecture is chosen automatically to maximize the similarity of output statistics to clean condition. Results on phoneme recognition from noisy speech indicate the effectiveness of the proposed method.
On the acoustic properties of parallel arrangement of multiple micro-perforated panel absorbers with different cavity depths
Authors: Wang Chunqi , Huang Lixi
Published: July 2011

The acoustic properties of a compound micro-perforated panel (MPP) absorber array are investigated. The absorber array consists of three parallel-arranged MPP absorbers with different cavity depths. A finite element procedure is used to simulate its acoustic behaviors under normal incidence. Experimental studies are carried out to verify the numerical simulations. Due to different reactance matching conditions in the absorber array, strong local resonance occurs and the corresponding local resonance absorption dominates. Compared with single MPP absorber, the absorber array requires lower acoustic resistance for good absorption performance, and the resonance frequencies shift due to inter-resonator interactions. The different acoustic resistance requirement is explained by considering the reduced effective perforation rate of the MPP in the absorber array. The performance of the absorber array varies with the sizes and spatial arrangement of the component absorbers. When the distance between component absorbers is larger than a quarter-wavelength, the above-mentioned parallel absorption mechanism diminishes. In the experimental study, the normal incidence absorption coefficients of a prototype MPP absorber array are tested. The measured results compare well with the numerical predictions. The experimental study also shows that although other absorption mechanisms may exist, dissipation by the MPP is dominant in the MPP absorber array.
Particle motion measured at an operational wind turbine in relation to hearing sensitivity in fish
Authors: Sigray Peter , Andersson Mathias H.
Published: July 2011

The effect of sound pressure on the hearing of fish has been extensively investigated in laboratory studies as well as in field trials in contrast to particle motion where few studies have been carried out. To improve this dearth of knowledge, an instrument for measuring particle motion was developed and used in a field trial. The particle motion is measured using a neutrally buoyant sphere, which co-oscillates with the fluid motion. The unit was deployed in close vicinity to a wind turbine foundation at Utgrunden wind farm in the Baltic Sea. Measurements of particle motion were undertaken at different distances from the turbine as well as at varying wind speeds. Levels of particle motion were compared to audiograms for cod (Gadus morhua L.) and plaice (Pleuronectes platessa L.).
A methodological and preliminary study on the acoustic effect of a trumpet player’s vocal tract
Authors: Kaburagi Tokihiko , Yamada Naoyuki , Fukui Takashi , Minamiya Eriko
Published: July 2011

A methodological study is presented to examine the acoustic role of the vocal tract in playing the trumpet. Preliminary results obtained for one professional player are also shown to demonstrate the effectiveness of the method. Images of the vocal tract with a resolution of 0.5 mm (2 mm in thickness) were recorded with magnetic resonance imaging to observe the tongue posture and estimate the vocal-tract area function during actual performance. The input impedance was then calculated for the player’s air column including both the supra- and subglottal tracts using an acoustic tube model including the effect of wall losses. Finally, a time-domain blowing simulation by Adachi and Sato [J. Acoust. Soc. Am. 99, 1200–1209 (1996)] was performed with a model of the lips. In this simulation, the oscillating frequency of the lips was slightly affected by using different shapes of the vocal tract measured for the player. In particular, when the natural frequency of the lips was gradually increased, the transition to the higher mode occurred at different frequencies for different vocal-tract shapes. Furthermore, simulation results showed that the minimum blowing pressure required to attain the lip oscillation can be reduced by adjusting the vocal-tract shape properly.
Recruiting Trouble
Authors: Foley John F.
Published: July 2011

The recruitment of a subset of monocytes to metastatic sites promotes metastasis through the release of vascular endothelial growth factor.
Genomic Medicine at Its Best
Authors: Lin Richard J.
Published: July 2011

Rare disease helps identify crucial molecular network in host defense against fungal infection.
Hawking radiation from a dynamical Kerr–Newman black hole
Authors: Ding Han , Liu Xian-Ming , Liu Wen-Biao
Published: July 2011

After Hawking radiation from a Schwarzschild black hole is calculated using the Damour–Ruffini method, the tortoise coordinate transformation in a static black hole is extended to a dynamical axisymmetric black hole, such as a dynamical Kerr–Newman black hole. Under the generalized tortoise coordinate transformation, Hawking radiation from a dynamical Kerr–Newman black hole is obtained successfully. Moreover, it also seems to occur on the apparent horizon instead of the event horizon.
Imaging of ultrafast electron motion in molecules
Authors: Barmaki Samira , Guessaf Karima , Laulan Stéphane
Published: July 2011

We probe the attosecond electron motion in [Formula: see text], at short internuclear distances, by exact numerical solution of the 3D time-dependent Schrödinger equation in the Born–Oppenheimer approximation. We simulate a pump-probe experiment to calculate the energy distributions of ionized electrons. We start the experiment with a pump pulse that creates a coherent electronic wavepacket combination of the 1sσg and 2pσu states. We let the electronic wavepacket oscillate during a time delay Δt. In the second step of the experiment, we submit the wavepacket to an intense attosecond X-ray laser pulse. We observe an asymmetry in the energy distributions of ionized electrons that allows the mapping of the attosecond electron motion in [Formula: see text].
Analytical evaluation of jamming transition problem
Authors: Ganji S.S. , Barari A. , Najafi M. , Domairry G.
Published: July 2011

This paper applies two powerful analytical approximation methods to the jamming transition problem (JTP) of traffic flow networks. The governing equations are modeled on the Lorentz system and take the form of a nonlinear nonconservative oscillator. We describe and implement the homotopy perturbation method (HPM) and the variational iteration method (VIM) to compute approximations to the JTP solution. Their solutions are compared with the purely numerical fourth-order Runge–Kutta solution. We conclude that both HPM and VIM provide highly accurate analytical solutions to the nonlinear jamming transition problem.
JET CONVERSIONS IN QUARK-GLUON PLASMA
Authors: KO CHE MING
Published: July 2011

In addition to loosing energy, a quark or gluon jet traversing through a quark-gluon plasma can also be converted to a gluon or quark jet through scattering with the thermal quarks and gluons. Their conversion rates due to two-body elastic [Formula: see text] and inelastic [Formula: see text] scattering have been evaluated in the lowest order in QCD. Including both energy loss and conversions of quark and gluon jets in the expanding quark-gluon plasma produced in relativistic heavy ion collisions, a net conversion of quark jets to gluon jets has been found. This reduces the difference between the nuclear modification factors for quark and gluon jets in heavy ion collisions and thus enhances the ratios of high transverse momentum protons and antiprotons to pions that are produced from the fragmentation of these jets. To account for the observed similar ratios in central Au + Au and p + p collisions at same energy requires, however, a much larger net quark to gluon jet conversion rate than that given by the lowest-order QCD, indicating the importance of higher-order processes and the strongly coupling nature of the quark-gluon plasma in describing the propagation of jets in the quark-gluon plasma.
Nature of Graphene Edges: A Review
Authors: Acik Muge , Chabal Yves J.
Published: July 2011

Graphene edges determine the optical, magnetic, electrical, and electronic properties of graphene. In particular, termination, chemical functionalization and reconstruction of graphene edges leads to crucial changes in the properties of graphene, so control of the edges is critical to the development of applications in electronics, spintronics and optoelectronics. Up to date, significant advances in studying graphene edges have directed various smart ways of controlling the edge morphology. Though, it still remains as a major challenge since even minor deviations from the ideal shape of the edges significantly deteriorate the material properties. In this review, we discuss the fundamental edge configurations together with the role of various types of edge defects and their effects on graphene properties. Indeed, we highlight major demanding challenges to find the most suitable technique to characterize graphene edges for numerous device applications such as transistors, sensors, actuators, solar cells, light-emitting displays, and batteries in graphene technology.
4H-SiC(0001) Basal Plane Stability during the Growth of Epitaxial Graphene on Inverted-Mesa Structures
Authors: Ushio Shoji , Kutsuma Yasunori , Yoshii Arata , Tamai Naoto , Ohtani Noboru , Kaneko Tadaaki
Published: July 2011

The epitaxial graphene growth at the 4H-SiC(0001) surface with intentionally inserted step-free basal plane regions was performed by high temperature annealing in the range of 1600–1900 °C under ultrahigh vacuum. For fabricating inverted-mesa structures with the step-free regions at SiC surfaces, a combined process consisting of a direct laser digging and a Si-vapor etching at 1900 °C was utilized. The graphitized surfaces were characterized by atomic force microscopy, low acceleration voltage (0.1–1.0 kV) scanning electron microscopy and Raman spectroscopy. It was found that the graphene thickness at the SiC step-free surface tends to be suppressed compared with the thickness at background SiC step-terrace surfaces where the steps are intrinsically introduced from intentional/unintentional substrate miscut angles. From the characterization by Raman mapping, 1 ML graphene was obtained at the SiC step-free surface at 1600 °C graphitization in contrast to the case that multilayer graphene was grown at SiC step-terrace surfaces.
Oxygen-Induced Reduction of the Graphitization Temperature of SiC Surface
Authors: Imaizumi Kei , Handa Hiroyuki , Takahashi Ryota , Saito Eiji , Fukidome Hirokazu , Enta Yoshiharu , Teraoka Yuden , Yoshigoe Akitaka , Suemitsu Maki
Published: July 2011

In the solid–vapor phase equilibria between SiC and O2 system, there exists a region where the reaction (2+x)SiC+O2→(2+x)Si↑+ 2CO↑+ xC↓ takes place [Y. W. Song and F. W. Smith: J. Am. Ceram. Soc. 88 (2005) 1864]. By tuning the temperature and the oxygen pressure used in the graphitization annealing into this region, we have succeeded in the growth of epitaxial graphene on SiC crystals at 1000 °C, which is lower, by 250 °C or more, than the conventional epitaxial graphene method. The method is especially useful to formation of epitaxial graphene on silicon (GOS), which requires a lower graphitization temperature because of the Si substrate as well as of its mission to attain compatibility with Si technology.
Controllability of Electrical Conductivity by Oxygen Vacancies and Charge Carrier Trapping at Interface between CoO and Electrodes
Authors: Kishi Hirofumi , Sarhan Abdulla Ali Abdulla , Sakaue Mamoru , Aspera Susan Meñez , David Melanie Yadao , Nakanishi Hiroshi , Kasai Hideaki , Tamai Yukio , Ohnishi Shigeo , Awaya Nobuyoshi
Published: July 2011

Recently, the role of resistance random access memory (RRAM) is becoming extremely important in the development of nonvolatile memories. RRAM works by changing the resistance of the transition metal oxide contained in RRAM after the application of a sufficiently high voltage, however, this switching mechanism has not been fully clarified. In this study, by performing first principles calculations based on the density functional theory, we first investigate the change in the property of bulk CoO resulting from oxygen vacancies and charge carrier trapping in the vicinity of the oxygen vacancies. Next, we perform calculations for slab models of CoO in contact with Ta, W, and Pt electrodes and hence investigate the effects of oxygen vacancies at the interface between the CoO layer and the electrode layer. On the basis of the obtained results, we conclude that W is the most suitable electrode material compared with Ta and Pt.
Phase Change Characteristics of InxSb40-xTe60 Chalcogenide Alloy for Phase Change Random Access Memory
Authors: Yun Jae-Jin , Lee Won-Jong
Published: July 2011

The In
x
Sb40-x
Te60 alloy was selected as a new alternative phase change material for Ge2Sb2Te5 (GST) for phase change random access memory (PRAM). The crystal structure of In
x
Sb40-x
Te60 was an α(Sb2Te3) rhombohedral (a=b=c, α=β=γ≠90°) single phase with identical lattice parameters in a wide composition range of In (0–28 at. %). The crystallization temperature and melting point of In
x
Sb40-x
Te60 were in the ranges of 149–219 °C and 608–614 °C, respectively, and similar to those of GST. The electric properties of In
x
Sb40-x
Te60 with a wide composition range of In contents showed the typical PRAM properties such as current–voltage (I–V), resistance–voltage (R–V), and switching behavior. The reset current of In
x
Sb40-x
Te60 decreased with increasing In content and the low power consumption and good retention can be realized by controlling In content. The ratio of the cell resistance and sheet resistance of amorphous In
x
Sb40-x
Te60 to those crystalline In
x
Sb40-x
Te60 were almost the same as or larger than those of GST. The cycling endurance test of In
x
Sb40-x
Te60 with a wide range of In contents showed the comparable results to GST. In
x
Sb40-x
Te60 was concluded to be a very promising phase change material for PRAM.
Passivation of Germanium Surfaces by a Quinhydrone–Methanol Solution Treatment
Authors: Swain Bibhu P. , Takato Hidetaka , Sakata Isao
Published: July 2011

The bulk lifetime of minority carriers, τb, in germanium (Ge) is one of the most important material parameters in the design and fabrication of Ge-based solar cells. Surface passivation of Ge substrates is indispensable to the accurate evaluation of τb. We have found that a newly developed wet chemical treatment, quinhydrone–methanol (Q/M) solution treatment, effectively passivates Ge surfaces, achieving a surface recombination velocity (S) of less than 20 cm/s. It has been clarified that oxide layers containing the molecules from the Q/M solution were formed on the Ge surfaces treated with the Q/M solution. Ge dangling bonds (DBs) are thought to be terminated by these oxygen related molecules. Band bending in the Ge substrates induced by the oxide layers adsorbed on the Q/M-treated Ge surface can contribute to the reduction in S. We also briefly discuss the properties of a recombination center found in the bulk of highly resistive Ge substrates.
Enhancement of Third-Order Optical Susceptibility in Polythiophene Thin Films Fabricated by Drop Casting Using Anhydrous Solvent
Authors: Kobayashi Takashi , Endo Toshiyuki , Shinke Wataru , Nagase Takashi , Murakami Shuichi , Naito Hiroyoshi
Published: July 2011

To maximize the potential of poly(3-hexylthiophene) (P3HT) as a nonlinear optical material, we examined the conditions for fabricating thin films. The results indicate that the third-order optical susceptibility χ(3), which was determined by electroabsorption spectroscopy, is fourfold enhanced when thin films are drop cast from an anhydrous chloroform solution in an inert atmosphere, compared with the χ(3) of spin-coated thin films prepared in an ambient atmosphere. Fabricating the thin films in an O2- and water-free environment is essential for obtaining large χ(3) values. Under these conditions, we determined the maximum value of the imaginary part of χ(3) for P3HT to be 2.2 ×10-9 esu.
Dynamic Driving Current Using Side Gate Bias of Single-Electron Transistors
Authors: Lee Joung-Eob , Kim Garam , Kim Kyung-Wan , Lee Jung-Han , Kang Kwon-Chil , Lee Jong-Ho , Shin Hyungcheol , Park Byung-Gook
Published: July 2011

Single-electron transistors (SETs) with an electrically formed Coulomb island are proposed and fabricated on the basis of the sidewall patterning on the recessed channel structure. The fabricated device is based on a silicon-on-insulator (SOI) wafer. The quantum dot (QD) is caused by the electrically induced tunneling barriers with n-doped polycrystalline silicon (poly-Si) sidewall gates on the active surface. These devices with side gates are more advantageous in terms of the room-temperature operation and controllability of oscillation peaks for application circuits. This is because the dimensions of the Coulomb island and oscillation peak are modified by the side gate bias. The side gate dependence of the fabricated SET with a recessed channel structure is characterized through a device simulator.
Decrease in Interference Effects between Cells for Metal–Oxide–Nitride–Oxide–Silicon NAND Flash Memory Devices with Metal Spacer Layers
Authors: Kim Sung Ho , You Joo Hyung , Kim Tae Whan
Published: July 2011

Nanoscale metal–oxide–nitride–oxide–silicon (MONOS) NAND flash memory devices with a metal spacer layer were designed to increase the fringing field and the coupling ratio of the control gate and to decrease the interference effects between the cells. The simulation results showed that the drain current and the threshold voltage shift of the MONOS NAND flash memory devices utilizing a metal spacer increased owing to the increase in the fringing field and the coupling ratio. The electric field on the channel surface of the memory devices with a metal spacer layer increased, indicative of the achievement of the maximum fringing field effect, resulting in an increase in the drain current. The simulation results showed that the interference effects for the memory devices utilizing a metal spacer decreased resulting from the shielding of the electric field between neighboring cells.
Measurements of Rotational Temperature and Density of Molecular Nitrogen in Spark-Plug Assisted Atmospheric-Pressure Microwave Discharges by Rotational Raman Scattering
Authors: ElSabbagh Mansour , Kado Shinichiro , Ikeda Yuji , Sasaki Koichi
Published: July 2011

Rotational Raman scattering was adopted for measuring the spatiotemporal evolutions of the rotational temperature (Tr) and the density (nN2) of molecular nitrogen at the electronic ground state in spark-plug assisted atmospheric-pressure microwave discharge. The rotational temperature had a spatial distribution with the peak at the plasma center. The temporal evolution ofTrsuggests a long confinement time of heat in this plasma source. Because of the long confinement time of heat, the plasma was in a nonequilibrium state for at least ∼1 ms after the initiation of the discharge. We observed the depletion ofnN2as well as the decrease in the partial pressure of N2(PN2). They were more significant at a longer distance from the plasma center. The depletion ofnN2at the plasma center was roughly explained by the increase inTr. On the other hand, we have speculated that the significant decreases innN2andPN2in the peripheral region of the plasma is owing to dissociation of N2followed by nitriding of solid surfaces.
Effects of Post-SiH4 and Plasma Treatments on Chemical Vapor Deposited Cu Seeds with Chemical Vapor Deposited TiN Barrier in Porous Low Dielectric Constant and Cu Integration
Authors: Pyo Sung Gyu , Park Shangkyun , Park Hansoo , Lee Donghyun
Published: July 2011

A Cu seed deposited by chemical vapor deposition (CVD) was integrated with a CVD TiN barrier and electroplated Cu in a double level metal interconnect scheme using a dual damascene process. The post-SiH4 treatment of CVD TiN inhibits agglomeration of thin Cu by improving the wettability of Cu seeds as well as reducing the TiN sheet resistance. Post-plasma treatment on CVD Cu seeds decreases impurities in CVD Cu and eliminates interface voids between the CVD Cu seed and electroplated Cu, improving the gap filling properties of electroplated Cu layers. Inherently poor adhesion of the CVD Cu layers between the Cu barrier metal and the electroplated Cu is overcome by CVD TiN post treatments and CVD Cu post-plasma treatment. Bias-thermal-stress (BTS) tests were performed to verify the effect of post-SiH4 treatment. The SiH4 treated CVD TiN barrier and CVD Cu seed show feasibility for 65-nm technology in terms of low via resistance and chain yields.
Thermoelastic Damping in Micromechanical Resonators with a Proof Mass and a Network of Suspension Beams
Authors: Li Pu , Hu Rufu
Published: July 2011

Predicting thermoelastic damping is crucial for the design of highQmicromechanical resonators. In the past, for microresonators which consist of a proof mass and a network of suspension beams, some experiments showed that Zener's model [Phys. Rev. 52 (1937) 230; Phys. Rev. 53 (1938) 90] and Lifshitz and Roukes' model [Phys. Rev. B 61 (2000) 5600] can give a reasonable prediction, and others experiments showed that the two models fail to give a reasonable prediction. Few works give a reasonable and detailed explanation for this phenomenon. In this paper, a general proof is presented that shows Lifshitz and Roukes' model is valid for microresonators with a proof mass support by a network of suspension beams if all suspension beams are operated at pure bending vibration and all suspension beams have the same thickness. The accuracy of Lifshitz and Roukes' model is verified by comparing its results with the experimental results available in the literature.
Design of Optical Isolator with Sputter-Deposited Si Layer Employing Nonreciprocal Radiation-Mode Conversion
Authors: Yokoi Hideki , Yamaguchi Kazuya , Uchiumi Yuki
Published: July 2011

An optical isolator with a Si guiding layer that employs a nonreciprocal guided-radiation mode conversion is discussed. The Si guiding layer was sputter-deposited on a magnetic-garnet cladding layer. A magnetooptic waveguide in the optical isolator had an air/Si/magnetic-garnet structure. A nonreciprocal phase shift in the magnetooptic waveguide was calculated at a wavelength of 1.55 µm. The optical isolator employing the nonreciprocal guided-radiation mode conversion was designed for 1.55 µm.
Low-Frequency Forbidden Bands in Phononic Crystal Plates with Helmholtz Resonators
Authors: Hsu Jin-Chen
Published: July 2011

A theoretical investigation of Lamb wave propagation in two-dimensional phononic crystals composed of an array of solid Helmholtz resonators (HRs) on a thin plate is presented. The dispersion relations, power transmission spectra, and spectra of resonances are calculated by finite-element analysis. Owing to the simultaneous mechanisms of local resonances and Bragg scattering, the structure exhibits low-frequency forbidden bands and Bragg band gaps that can be effectively shifted by changing the geometry of the HRs. As a result, low-frequency band gaps within the audible range can be achieved. Furthermore, the calculated power transmission and resonance spectra for a finite phononic crystal structure show an evident resonance nature and are directly related to the formation of low-frequency band gaps. The spectra of the monolayer HR structure show that the resonances can either induce high reflection or intensify transmission. The effects of different excitation conditions for generating different Lamb wave modes on the transmission of the wave energy are also studied. The calculated results show that the transmission varies with the incident Lamb waves of different modes.
Low-Viscosity Measurement by Capillary Electromagnetically Spinning Technique
Authors: Hosoda Maiko , Hirano Taichi , Sakai Keiji
Published: July 2011

We study sphere rotation against viscous torque confined in a small space. Our new invention, the electromagnetically spinning sphere (EMS) viscometer measures liquid viscosity through the observation of sphere rotation driven by electromagnetic interaction in a noncontact manner. The lower limit of the measurable viscosity is determined from the ratio between the viscous torque and the mechanical friction, and the apparent increase in the contribution of the viscous term leads to the improvement of the accuracy of low-viscosity measurement. We propose a theoretical expression of the torque applied to a sphere rotating in a cylinder and obtained the power law with respect to the gap in between. The results of the numerical simulation and experiment provide evidence of the validity of the theory.