bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Primary Stability of Self‐Tapping and Non‐Self‐Tapping Dental Implants. A 12‐Week Clinical Study
Authors: Marković Aleksa , Calvo‐Guirado José Luís , Lazić Zoran , Gómez‐Moreno Gerardo , Ćalasan Dejan , Guardia Javier , Čolic Snježana , Aguilar‐Salvatierra Antonio , Gačić Bojan , Delgado‐Ruiz Rafael , Janjić Bojan , Mišić Tijana
Published: December 2011

Purpose: The aim of this study was to investigate the relationship between surgical techniques and implant macro‐design (self‐tapping/non‐self‐tapping) for the optimization of implant stability in the low‐density bone present in the posterior maxilla using resonance frequency analysis (RFA).

Materials and Methods: A total of 102 implants were studied. Fifty‐six self‐tapping BlueSkyBredent® (Bredent GmbH&Co.Kg®, Senden, Germany) and 56 non‐self‐tapping Standard Plus Straumann® (Institut Straumann AG®, Waldenburg, Switzerland) were placed in the posterior segment of the maxilla. Implants of both types were placed in sites prepared with either lateral bone‐condensing or with bone‐drilling techniques. Implant stability measurements were performed using RFA immediately after implant placement and weekly during a 12‐week follow‐up period.

Results: Both types of implants placed after bone condensing achieved significantly higher stability immediately after surgery, as well as during the entire 12‐week observation period compared with those placed following bone drilling. After bone condensation, there were no significant differences in primary stability or in implant stability after the first week between both implant types. From 2 to 12 postoperative weeks, significantly higher stability was shown by self‐tapping implants. After bone drilling, self‐tapping implants achieved significantly higher stability than non‐self‐tapping implants during the entire follow‐up period.

Conclusions: The outcomes of the present study indicate that bone drilling is not an effective technique for improving implant stability and, following this technique, the use of self‐tapping implants is highly recommended. Implant stability optimization in the soft bone can be achieved by lateral bone‐condensing technique, regardless of implant macro‐design.
Evaluation of the Esthetic Results of 64 Nonfunctional Immediately Loaded Postextraction Implants in the Maxilla: Correlation between Interproximal Alveolar Crest and Soft Tissues at 3 Years of Follow‐Up
Authors: Malchiodi Luciano , Cucchi Alessandro , Ghensi Paolo , Nocini Pier Francesco
Published: December 2011

Purpose: Many authors have emphasized that immediate loading protocols enable better esthetic results to be achieved compared with delayed loading, especially in the case of postextraction implants that are capable of maintaining the original esthetics of soft tissues. The aim of this study was to establish correlations between the interproximal crest, interproximal papilla, and marginal facial gingiva of immediately loaded postextraction implants by evaluating clinical and radiographic data.

Materials and Methods: Fifty‐eight consecutive patients underwent a tooth extraction and immediate implant placement with 64 postextraction implants, which were immediately loaded using a provisional single crown from June 2005 to December 2006. At 6 months after surgery, all implants were restored with a definitive single crown. Clinical and radiographic data were recorded at the time of surgery, at the time of definitive restoration, and after 3 years of functioning, in order to evaluate soft tissues esthetics and bone tissue condition. Statistical analysis was used to assess significant correlations between the interproximal crest, interproximal papilla, and marginal facial gingiva (p = 0.05).

Results: After 3 years of functioning, the implant success rate was 100% because no implants had failed. All parameters were stable and steady during the 3‐year follow‐up. The regression test revealed a statistically significant correlation between interproximal crest levels and interproximal papilla volume (p = 0.0134), and also between interproximal crest levels and marginal gingiva levels (p = 0.0226).

Conclusions: Postextraction immediately loaded implants represent a predictable technique that should be considered the treatment of choice in cases of single anterior tooth restoration and other cases. Esthetic results seem to depend on correct positioning of the implants, considering the correlation between bone tissue and related soft tissues. Maintaining the original condition of both bone and soft tissues around the tooth to be removed is the key to obtaining optimal esthetic outcomes.
Antagonistic regulation of transmembrane 4 L6 family member 5 attenuates fibrotic phenotypes in CCl4‐treated mice
Authors: Kang Minkyung , Jeong Soo‐Jin , Park Sook Young , Lee Hyo Jeong , Kim Hyun Jeong , Park Ki Hun , Ye Sang‐Kyu , Kim Sung‐Hoon , Lee Jung Weon
Published: December 2011

The development of liver fibrosis from chronic inflammation can involve epithelial–mesenchymal transition (EMT). Severe liver fibrosis can progress to cirrhosis, and further to hepatocellular carcinoma. Because the tetraspanin transmembrane 4 L6 family member 5 (TM4SF5) induces EMT and is highly expressed in hepatocellular carcinoma, it is of interest to investigate whether TM4SF5 expression is correlated with EMT processes during the development of fibrotic liver features. Using hepatic cells in vitro and a CCl4‐mediated mouse liver in vivo model, we examined whether TM4SF5 is expressed during liver fibrosis mediated by CCl4 administration and whether treatment with anti‐TM4SF5 reagent blocks the fibrotic liver features. Here, we found that TM4SF5 expression was induced by the transforming growth factor (TGF)β1 and epidermal growth factor signaling pathways in hepatocytes in vitro. In the CCl4‐mediated mouse liver model, TM4SF5 was expressed during the liver fibrosis mediated by CCl4 administration and correlated with α‐smooth muscle actin expression, collagen I deposition, and TGFβ1 and epidermal growth factor receptor signaling activation in fibrotic septa regions. Interestingly, treatment with anti‐TM4SF5 reagent blocked the TM4SF5‐mediated liver fibrotic features: the formation of fibrotic septa with α‐smooth muscle actin expression and collagen I deposition was attenuated by treatment with anti‐TM4SF5 reagent. These results suggest that TM4SF5 expression mediated by TGFβ1 and growth factor can facilitate fibrotic processes during chronic liver injuries. TM4SF5 is thus a candidate target for prevention of liver fibrosis following chronic liver injury.
Pharmacophore Modeling, 3D‐QSAR Studies, and in‐silico ADME Prediction of Pyrrolidine Derivatives as Neuraminidase Inhibitors
Authors: Zhang Jie , Pan Xiaoyan , Wang Chen , Wang Fang , Li Pengfei , Xu Wenfang , He Langchong
Published: December 2011

Neuraminidase (NA) is a major glycoprotein of influenza virus which is essential for viral infection. It offers a potential target for antiviral drug development. To develop potent NA inhibitors, pharmacophore models were generated by genetic algorithm with linear assignment for hypermolecular alignment of data sets. 3D‐QSAR studies were carried out on 49 molecules. Both comparative molecular field analysis (q2 = 0.720 and r2 = 0.947) and comparative molecular similarity indices analysis (q2 = 0.644 and r2 = 0.885) yielded reasonable results. A preliminary pharmacokinetic profile of these neuraminidase inhibitors was predicted using Volsurf module.
Dropping dead: causes and consequences of vulture population declines worldwide
Authors: Ogada Darcy L. , Keesing Felicia , Virani Munir Z.
Published: December 2011

Vultures are nature's most successful scavengers, and they provide an array of ecological, economic, and cultural services. As the only known obligate scavengers, vultures are uniquely adapted to a scavenging lifestyle. Vultures’ unique adaptations include soaring flight, keen eyesight, and extremely low pH levels in their stomachs. Presently, 14 of 23 (61%) vulture species worldwide are threatened with extinction, and the most rapid declines have occurred in the vulture‐rich regions of Asia and Africa. The reasons for the population declines are varied, but poisoning or human persecution, or both, feature in the list of nearly every declining species. Deliberate poisoning of carnivores is likely the most widespread cause of vulture poisoning. In Asia, Gyps vultures have declined by >95% due to poisoning by the veterinary drug diclofenac, which was banned by regional governments in 2006. Human persecution of vultures has occurred for centuries, and shooting and deliberate poisoning are the most widely practiced activities. Ecological consequences of vulture declines include changes in community composition of scavengers at carcasses and an increased potential for disease transmission between mammalian scavengers at carcasses. There have been cultural and economic costs of vulture declines as well, particularly in Asia. In the wake of catastrophic vulture declines in Asia, regional governments, the international scientific and donor communities, and the media have given the crisis substantial attention. Even though the Asian vulture crisis focused attention on the plight of vultures worldwide, the situation for African vultures has received relatively little attention especially given the similar levels of population decline. While the Asian crisis has been largely linked to poisoning by diclofenac, vulture population declines in Africa have numerous causes, which have made conserving existing populations more difficult. And in Africa there has been little government support to conserve vultures despite mounting evidence of the major threats. In other regions with successful vulture conservation programs, a common theme is a huge investment of financial resources and highly skilled personnel, as well as political will and community support.
The association between pterygium and conjunctival ultraviolet autofluorescence: The Norfolk Island Eye Study
Authors: Sherwin Justin C. , Hewitt Alex W. , Kearns Lisa S. , Griffiths Lyn R. , Mackey David A. , Coroneo Minas T.
Published: December 2011

Purpose:  To investigate the association between conjunctival ultraviolet autofluorescence (UVAF), a biomarker of ocular ultraviolet radiation (UVR) exposure, and prevalent pterygium.

Methods:  We conducted a cross‐sectional study on Norfolk Island, South Pacific. All permanent residents aged ≥15 were invited to participate. Participants completed a sun exposure questionnaire and underwent autorefraction and slit lamp biomicroscope examination. Area of conjunctival UVAF (sum of temporal/nasal area in right and left eyes) was determined using computerized methods. Multivariate logistic and linear regression models were used to estimate the associations with pterygia and UVAF, respectively.

Results:  Of 641 participants, 70 people (10.9%) had pterygium in one or both eyes, and prevalence was higher in males (15.0% versus 7.7%, p = 0.003). Significant independent associations with pterygium in any eye were UVAF (per 10 mm2) [odds ratio (OR) 1.16, 95% confidence interval (CI) 1.16–1.28, p = 0.002], tanning skin phenotype (OR 2.17, 1.20–3.92, p = 0.010) and spending more than three‐quarters of the day outside (OR 2.22, 1.20–4.09, p = 0.011). Increasing quartile of UVAF was associated with increased risk of pterygium following adjustment of age, sex and time outdoors (pTrend = 0.002). Independent associations with increasing UVAF (per 10 mm2) were decreasing age, time outdoors, skin type and male gender (all p < 0.001). UVAF area correlated well with the duration of outdoor activity (pTrend < 0.001).

Conclusion:  Pterygium occurs in approximately one‐tenth of Norfolk Islanders. Increasing conjunctival UVAF is associated with prevalent pterygia, confirming earlier epidemiological, laboratory and ray‐tracing studies that pterygia are associated with UVR. Protection from the sun should be encouraged to reduce the prevalence of pterygium in the community.
Sine wave mesopic contrast sensitivity – defining the normal range in a young population
Authors: Haughom Bente , Strand Trond‐Eirik
Published: December 2011

Purpose:  Limited information is available regarding the normal range of mesopic sine wave contrast sensitivity (CS). The aim of this study was therefore to define a reference range and in addition to identify factors related to mesopic CS in a young population.

Methods:  Individuals with normal visual acuity (VA) were included from a population of air crew members visiting the Institute of Aviation Medicine for routine medical examinations. CS was measured using the Optec 6500/FACT and evaluated by (i) the CS curve with five frequencies and (ii) the index of contrast sensitivity (ICS). ICS was defined as the sum of the weighted differences from the median CS value for each frequency. Multivariate analyses were performed to identify factors related to CS.

Results:  In a total of 197 subjects included, the mean mesopic CS score was significantly lower compared to the corresponding photopic measurements for all five frequencies tested. Median CS score for frequencies 1.5, 3, 6, 12 and 18 cycles per degree was 50, 114, 180, 60 and 33 for photopic and 71, 80, 90, 22 and 12 for mesopic (− glare) conditions, respectively. Better binocular VA was positively associated, while the use of corrective lenses was negatively associated with CS performance.

Conclusion:  We have provided reference values for mesopic CS and identified factors important for CS. The difference between mesopic and photopic measurements highlights the need for separate population norms. The new ICS score may be a useful collective descriptor of the traditional CS curve with five frequencies.
Compositional constraints on the genesis of diogenites
Authors: MITTLEFEHLDT David W. , BECK Andrew W. , LEE Cin‐Ty A. , McSWEEN Harry Y. , BUCHANAN Paul C.
Published: December 2011

Abstract– We have done bulk rock compositional analyses (INAA, ICP‐MS) and petrologic study of a suite of diogenite meteorites. Most contain orthopyroxenes with mg#s of 70.6–79.0. Meteorite Hills (MET) 00425 is magnesian (mg# of 83.9). Lewis Cliff (LEW) 88011 contains orthopyroxene grains of varying mg# (76.3–68.6). Queen Alexandra Range (QUE) 93009 (orthopyroxene mg# 70.6) contains coarse‐grained noritic clasts (plagioclase An84.7–88.3), and is rich in incompatible trace elements. It has Eu/Eu* < 1, indicating that cumulate norites do not dominate its trace element inventory. Queen Alexandra Range 93009 may be transitional between diogenites and magnesian cumulate eucrites. Lewis Cliff 88679, a dimict breccia of harzburgite and orthopyroxenite, has anomalously low concentrations of highly incompatible elements (e.g., Nb, La, Ta, U) compared to other diogenites, but is similar to them in less highly incompatible elements (e.g., Y, Zr, Yb, Hf). It is unlikely that this characteristic reflects a low proportion of a trapped melt component. The highly incompatible elements were likely mobilized after impact mixing of the two parent lithologies. Graves Nunataks 98108 shows an extreme range in Eu/Eu* attributable to the heterogeneous distribution of plagioclase; one sample has the lowest Eu/Eu* among diogenites. We find no compelling evidence to support the hypothesis that diogenite parent magmas were contaminated by partial melts of the eucritic crust. We posit that subsolidus equilibration between orthopyroxene and minor/trace phases (including phosphates) resulted in preferential redistribution of Eu2+ relative to Eu3+ and other rare earth elements, and results in anomalously low Eu/Eu* in samples leached in acids that dissolve phosphates.
Significantly increased risk of cancer in diabetes mellitus patients: A meta‐analysis of epidemiological evidence in Asians and non‐Asians
Authors: Noto Hiroshi , Tsujimoto Tetsuro , Noda Mitsuhiko
Published: December 2011

Aims/Introduction:  Emerging evidence from observational studies suggests that diabetes mellitus affects the cancer risk. However, whether there are differences in the magnitude of the influence of diabetes among ethnic groups is unknown.

Materials and Methods:  We searched MEDLINE and the Cochrane Library for pertinent articles that had been published as of 4 April 2011, and included them in a meta‐analysis of the risk of all‐cancer mortality and incidence in diabetic subjects.

Results:  A total of 33 studies were included in the meta‐analysis, and they provided 156,132 diabetic subjects for the mortality analysis and 993,884 for the incidence analysis. Cancer mortality was approximately 3%, and cancer incidence was approximately 8%. The pooled adjusted risk ratio (RR) of all‐cancer mortality was significantly higher than for non‐diabetic people (RR 1.32 [CI 1.20–1.45] for Asians; RR 1.16 [CI 1.01–1.34] for non‐Asians). Diabetes was also associated with an increased RR of incidence across all cancer types (RR 1.23 [CI 1.09–1.39] for Asians; RR 1.15 [CI 0.94–1.43] for non‐Asians). The RR of incident cancer for Asian men was significantly higher than for non‐Asian men (P = 0.021).

Conclusions:  Diabetes is associated with a higher risk for incident cancer in Asian men than in non‐Asian men. In light of the exploding global epidemic of diabetes, particularly in Asia, a modest increase in the cancer risk will translate into a substantial socioeconomic burden. Our current findings underscore the need for clinical attention and better‐designed studies of the complex interactions between diabetes and cancer. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00183.x, 2012)
Biased thinking assessed by external observers in borderline personality disorder
Authors: Kramer Ueli , Vaudroz Cynthia , Ruggeri Ornella , Drapeau Martin
Published: December 2011

Objectives. Biased thinking (to some extent overlapping with the concepts of cognitive distortions and cognitive errors) is a key concept in cognitive therapy of Borderline Personality Disorder (BPD). Specific contents and cognitive processes related to BPD functioning are known. However, most studies are based on self‐report measures which present a number of important limitations, in particular the difficulty in assessing non‐conscious processes infused by affect. So far, no studies were conducted using valid observer‐rated methodology addressing the question of biased thinking in BPD as it unfolds spontaneously in session.

Design. This is a controlled interview study comparing two matched groups, BPD patients and healthy controls.

Methods. A total of N= 25 clinical dynamic interviews with patients presenting with BPD were transcribed and rated using the Cognitive Errors Rating Scale (Drapeau, Perry, & Dunkley, 2008); their cognitive profiles were compared to those of N= 25 healthy controls who underwent the same procedure.

Results. Overall, results indicated that no between‐group difference in the frequency of specific biases was found. However, heightened levels of negative cognitive biases, in particular over‐generalizing and fortune‐telling, were associated with BPD. Furthermore, negative over‐generalizing was associated with the number of BPD symptoms.

Conclusions. These results have high levels of ecological validity and are promising for the refinement of cognitive theory of BPD. Clinical implications for assessment and intervention are discussed.
Vocalization control in Mongolian gerbils (Meriones unguiculatus) during locomotion behavior
Authors: Nishiyama Kohei , Kobayasi Kohta I. , Riquimaroux Hiroshi
Published: December 2011

The vocalization behavior of Mongolian gerbils, a model animal of auditory physiology, was examined. A pair of gerbils was placed in a chamber, and their species-specific vocalizations and locomotive behaviors were recorded and analyzed. Two types of calls were predominantly produced: high-frequency upward frequency-modulated (HU-FM) calls and low-frequency multi-harmonic frequency-modulated (LM-FM) calls. Emission rates of HU-FM calls significantly decreased as the distance between the two gerbils increased, and playback of simulated HU-FM calls increased the emission rates. Acoustic analysis of HU-FM calls showed that the calls exhibited a stereotypic spectro-temporal structure including a fixed inter-onset interval (100–175 ms) and that individual differences in the frequency could convey the body size of the callers. The timing of HU-FM calls was highly synchronized with jump movements when an animal vocalized while jumping, suggesting the existence of tight locomotor-vocal coupling. Conversely, LM-FM calls were observed only when the gerbils tactilely contacted with each other while fighting over a food. These results suggest that Mongolian gerbils change the rates of call emissions and call types (e.g., LM-FM or HU-FM calls) in response to changes in visual and possibly tactile and auditory information. The functions of both calls are discussed in terms of their acoustic structures.
Perception of intonation in Mandarin Chinese
Authors: Yuan Jiahong
Published: December 2011

There is a tendency across languages to use a rising pitch contour to convey question intonation and a falling pitch contour to convey a statement. In a lexical tone language such as Mandarin Chinese, rising and falling pitch contours are also used to differentiate lexical meaning. How, then, does the multiplexing of the F0 channel affect the perception of question and statement intonation in a lexical tone language? This study investigated the effects of lexical tones and focus on the perception of intonation in Mandarin Chinese. The results show that lexical tones and focus impact the perception of sentence intonation. Question intonation was easier for native speakers to identify on a sentence with a final falling tone and more difficult to identify on a sentence with a final rising tone, suggesting that tone identification intervenes in the mapping of F0 contours to intonational categories and that tone and intonation interact at the phonological level. In contrast, there is no evidence that the interaction between focus and intonation goes beyond the psychoacoustic level. The results provide insights that will be useful for further research on tone and intonation interactions in both acoustic modeling studies and neurobiological studies.
Vibration responses of the organ of Corti and the tectorial membrane to electrical stimulation
Authors: Nowotny Manuela , Gummer Anthony W.
Published: December 2011

Coupling of somatic electromechanical force from the outer hair cells (OHCs) into the organ of Corti is investigated by measuring transverse vibration patterns of the organ of Cori and tectorial membrane (TM) in response to intracochlear electrical stimulation. Measurement places at the organ of Corti extend from the inner sulcus cells to Hensen’s cells and at the lower (and upper) surface of the TM from the inner sulcus to the OHC region. These locations are in the neighborhood of where electromechanical force is coupled into (1) the mechanoelectrical transducers of the stereocilia and (2) fluids of the organ of Corti. Experiments are conducted in the first, second, and third cochlear turns of an in vitro preparation of the adult guinea pig cochlea. Vibration measurements are made at functionally relevant stimulus frequencies (0.48–68 kHz) and response amplitudes (<15 nm). The experiments provide phase relations between the different structures, which, dependent on frequency range and longitudinal cochlear position, include in-phase transverse motions of the TM, counterphasic transverse motions between the inner hair cell and OHCs, as well as traveling-wave motion of Hensen’s cells in the radial direction. Mechanics of sound processing in the cochlea are discussed based on these phase relationships.
Production of contrast between sibilant fricatives by children with cochlear implants
Authors: Todd Ann E. , Edwards Jan R. , Litovsky Ruth Y.
Published: December 2011

Speech production by children with cochlear implants (CIs) is generally less intelligible and less accurate on a phonemic level than that of normally hearing children. Research has reported that children with CIs produce less acoustic contrast between phonemes than normally hearing children, but these studies have included correct and incorrect productions. The present study compared the extent of contrast between correct productions of /s/ and /∫/ by children with CIs and two comparison groups: (1) normally hearing children of the same chronological age as the children with CIs and (2) normally hearing children with the same duration of auditory experience. Spectral peaks and means were calculated from the frication noise of productions of /s/ and /∫/. Results showed that the children with CIs produced less contrast between /s/ and /∫/ than normally hearing children of the same chronological age and normally hearing children with the same duration of auditory experience due to production of /s/ with spectral peaks and means at lower frequencies. The results indicate that there may be differences between the speech sounds produced by children with CIs and their normally hearing peers even for sounds that adults judge as correct.
Enhancing the absorption coefficient of a backed rigid frame porous layer by embedding circular periodic inclusions
Authors: Groby J.-P. , Dazel O. , Duclos A. , Boeckx L. , Kelders L.
Published: December 2011

The acoustic properties of a porous sheet of medium static air flow resistivity (around 10 000Nms-4), in which a periodic set of circular inclusions is embedded and which is backed by a rigid plate, are investigated. The inclusions and porous skeleton are assumed motionless. Such a structure behaves like a multi-component diffraction grating. Numerical results show that this structure presents a quasi-total (close to unity) absorption peak below the quarter-wavelength resonance of the porous sheet in absence of inclusions. This result is explained by the excitation of a complex trapped mode. When more than one inclusion per spatial period is considered, additional quasi-total absorption peaks are observed. The numerical results, as calculated with the help of the mode-matching method described in this paper, agree with those calculated using a finite element method.
Dynamic-range compression affects the lateral position of sounds
Authors: Wiggins Ian M. , Seeber Bernhard U.
Published: December 2011

Dynamic-range compression acting independently at each ear in a bilateral hearing-aid or cochlear-implant fitting can alter interaural level differences (ILDs) potentially affecting spatial perception. The influence of compression on the lateral position of sounds was studied in normal-hearing listeners using virtual acoustic stimuli. In a lateralization task, listeners indicated the leftmost and rightmost extents of the auditory event and reported whether they heard (1) a single, stationary image, (2) a moving/gradually broadening image, or (3) a split image. Fast-acting compression significantly affected the perceived position of high-pass sounds. For sounds with abrupt onsets and offsets, compression shifted the entire image to a more central position. For sounds containing gradual onsets and offsets, including speech, compression increased the occurrence of moving and split images by up to 57 percentage points and increased the perceived lateral extent of the auditory event. The severity of the effects was reduced when undisturbed low-frequency binaural cues were made available. At high frequencies, listeners gave increased weight to ILDs relative to interaural time differences carried in the envelope when compression caused ILDs to change dynamically at low rates, although individual differences were apparent. Specific conditions are identified in which compression is likely to affect spatial perception.
Ultrasonic backscatter coefficient quantitative estimates from high-concentration Chinese hamster ovary cell pellet biophantoms
Authors: Han Aiguo , Abuhabsah Rami , Blue James P. , Sarwate Sandhya , O’Brien William D.
Published: December 2011

Previous work estimated the ultrasonic backscatter coefficient (BSC) from low-concentration (volume density < 3%) Chinese Hamster Ovary (CHO, 6.7 -μm cell radius) cell pellets. This study extends the work to higher cell concentrations (volume densities: 9.6% to 63%). At low concentration, BSC magnitude is proportional to the cell concentration and BSC frequency dependency is independent of cell concentration. At high cell concentration, BSC magnitude is not proportional to cell concentration and BSC frequency dependency is dependent on cell concentration. This transition occurs when the volume density reaches between 10% and 30%. Under high cell concentration conditions, the BSC magnitude increases slower than proportionally with the number density at low frequencies (ka < 1), as observed by others. However, what is new is that the BSC magnitude can increase either slower or faster than proportionally with number density at high frequencies (ka > 1). The concentric sphere model least squares estimates show a decrease in estimated cell radius with number density, suggesting that the concentric spheres model is becoming less applicable as concentration increases because the estimated cell radius becomes smaller than that measured. The critical volume density, starting from when the model becomes less applicable, is estimated to be between 10% and 30% cell volume density.
Investigating acoustic correlates of human vocal fold vibratory phase asymmetry through modeling and laryngeal high-speed videoendoscopy
Authors: Mehta Daryush D. , Zañartu Matías , Quatieri Thomas F. , Deliyski Dimitar D. , Hillman Robert E.
Published: December 2011

Vocal fold vibratory asymmetry is often associated with inefficient sound production through its impact on source spectral tilt. This association is investigated in both a computational voice production model and a group of 47 human subjects. The model provides indirect control over the degree of left–right phase asymmetry within a nonlinear source–filter framework, and high-speed videoendoscopy provides in vivo measures of vocal fold vibratory asymmetry. Source spectral tilt measures are estimated from the inverse-filtered spectrum of the simulated and recorded radiated acoustic pressure. As expected, model simulations indicate that increasing left–right phase asymmetry induces steeper spectral tilt. Subject data, however, reveal that none of the vibratory asymmetry measures correlates with spectral tilt measures. Probing further into physiological correlates of spectral tilt that might be affected by asymmetry, the glottal area waveform is parameterized to obtain measures of the open phase (open/plateau quotient) and closing phase (speed/closing quotient). Subjects’ left–right phase asymmetry exhibits low, but statistically significant, correlations with speed quotient (r = 0.45) and closing quotient (r = −0.39). Results call for future studies into the effect of asymmetric vocal fold vibration on glottal airflow and the associated impact on voice source spectral properties and vocal efficiency.
Estimating the direct-to-reverberant energy ratio from the coherence between coincident pressure and particle velocity
Authors: Kuster Martin
Published: December 2011

An analytical expression for the relationship between the direct-to-reverberant energy ratio (DRR) and the coherence estimation function between coincident pressure and particle velocity component is derived. The analytical solution is first validated with simulated room impulse responses and then used to estimate the DRR in five octave bands for several receiver positions measured in a total of 11 rooms of vastly different sizes and acoustic characteristics. The accuracy is evaluated by comparison with the DRR estimated directly from the room impulse response. The difference is typically 5 dB. For two rooms, the variation of the DRR estimate with source-to-receiver position is also shown. The method is blind in the sense that it is virtually independent of the signal generated by a single sound source.
Observer-based beamforming algorithm for acoustic array signal processing
Authors: Bai Long , Huang Xun
Published: December 2011

In the field of noise identification with microphone arrays, conventional delay-and-sum (DAS) beamforming is the most popular signal processing technique. However, acoustic imaging results that are generated by DAS beamforming are easily influenced by background noise, particularly for in situ wind tunnel tests. Even when arithmetic averaging is used to statistically remove the interference from the background noise, the results are far from perfect because the interference from the coherent background noise is still present. In addition, DAS beamforming based on arithmetic averaging fails to deliver real-time computational capability. An observer-based approach is introduced in this paper. This so-called observer-based beamforming method has a recursive form similar to the state observer in classical control theory, thus holds a real-time computational capability. In addition, coherent background noise can be gradually rejected in iterations. Theoretical derivations of the observer-based beamforming algorithm are carefully developed in this paper. Two numerical simulations demonstrate the good coherent background noise rejection and real-time computational capability of the observer-based beamforming, which therefore can be regarded as an attractive algorithm for acoustic array signal processing.
The effect of carrier level on tuning in amplitude-modulation masking
Authors: Wojtczak Magdalena
Published: December 2011

The effect of carrier level on tuning in modulation masking was investigated for noise and tonal carriers. Bandwidths of the modulation filters, estimated from the masked detection thresholds using an envelope power spectrum model, were independent of level for the noise carrier but seemed to decrease with increasing level for the tonal carrier. However, the apparently sharper tuning could be explained by increased modulation sensitivity and modulation dynamic range with increasing level rather than improved modulation-frequency selectivity. Consistent with this interpretation, the addition of a high-pass noise with a level adjusted to maintain the same threshold for the detection of the signal modulation for each carrier level used eliminated the effect of level on tuning. Overall, modulation filters estimated from psychophysical data do not depend on level in contrast to the modulation transfer functions obtained from neural recordings in the inferior colliculus in physiological studies. The results highlight differences between the characteristics of modulation processing obtained from neural data and perception. The discrepancies indicate the need for further investigation into physiological correlates of tuning in modulation processing.
Fitness Trade-Offs and Environmentally Induced Mutation Buffering in Isogenic
C. elegans
Authors: Casanueva M. Olivia , Burga Alejandro , Lehner Ben
Published: December 2011

All Worms Are Not Equal

Why do specific mutations not affect all individuals who inherit them?

Casanueva
et al.

(p.
82
, published online 15 December; see the Perspective by

Deplancke and Verstrepen

) found that prior exposure to mild environmental stimuli and the stimulation of a stress response in the nematode
Caenorhabditis elegans
reduced the detrimental effects of diverse mutations. Moreover, because of interindividual variation in stress signaling, this protective effect was not the same in all individuals. In the absence of mutations, a stronger response increased stress resistance but also delayed reproduction. Such variability among individuals may be beneficial in an unpredictable environment, acting as a “bet-hedging” strategy to diversify risk.
Asymmetric B Cell Division in the Germinal Center Reaction
Authors: Barnett Burton E. , Ciocca Maria L. , Goenka Radhika , Barnett Lisa G. , Wu Junmin , Laufer Terri M. , Burkhardt Janis K. , Cancro Michael P. , Reiner Steven L.
Published: December 2011

Stochastic or Asymmetric Fate Determination?

During an adaptive immune response, B lymphocytes rapidly divide and differentiate into effector cell populations, including antibody-secreting plasmablasts and memory B cells. Many also change the class of antibody they secrete, through a process called isotype switching. During this process, some cells die. Whether cells acquire these different fates in a stochastic or programmed manner, however, is unclear.

Duffy
et al.

(p.
338
, published online 5 January) used single-cell tracking to determine the times to division, differentiation into a plasmablast, isotype switching, and death of stimulated B lymphocytes. Statistical analysis and mathematical modeling revealed that these cell-fate decisions appear to be the result of random clocks: Which clock went off first (division, differentiation, or death), determined the fate of the cell.

Barnett
et al.

(p.
342
, published online 15 December) sought to determine whether asymmetrical cell division, which is thought to contribute to effector cell-fate decisions in T cells, may be at work in B lymphocytes. Indeed, factors important for the initiation and maintenance of germinal center B lymphocyte identity, along with an ancestral polarity protein, were asymmetrically distributed and maintained their asymmetry during cell division.
Human Regulatory T Cells Rapidly Suppress T Cell Receptor–Induced Ca
2+
, NF-κB, and NFAT Signaling in Conventional T Cells
Authors: Schmidt Angelika , Oberle Nina , Weiß Eva-Maria , Vobis Diana , Frischbutter Stefan , Baumgrass Ria , Falk Christine S. , Haag Mathias , Brügger Britta , Lin Hongying , Mayr Georg W. , Reichardt Peter , Gunzer Matthias , Suri-Payer Elisabeth , Krammer Peter H.
Published: December 2011

Inhibition of calcium signaling is critical for the suppression of T cell responses by regulatory T cells.
A Distinct Interaction Mode Revealed by the Crystal Structure of the Kinase p38α with the MAPK Binding Domain of the Phosphatase MKP5
Authors: Zhang Yuan-Yuan , Wu Jia-Wei , Wang Zhi-Xin
Published: December 2011

Identification of the mechanism through which the kinase p38α interacts
with the phosphatase that inactivates it could lead to the development of more
specific anti-inflammatory drugs.
Protein O-GlcNAcylation Is Required for Fibroblast Growth Factor Signaling in
Drosophila
Authors: Mariappa Daniel , Sauert Kathrin , Mariño Karina , Turnock Daniel , Webster Ryan , van Aalten Daan M. F. , Ferguson Michael A. J. , Müller H.-Arno J.
Published: December 2011

Fibroblast growth factor signaling is connected to metabolism through the intracellular O-GlcNAcylation of the receptor complex.
Evolution of Tetragonal Phase in the FeSe Wire Fabricated by a Novel Chemical-Transformation Powder-in-Tube Process
Authors: Izawa Hiroki , Mizuguchi Yoshikazu , Ozaki Toshinori , Takano Yoshihiko , Miura Osuke
Published: December 2011

We fabricated superconducting FeSe wires by the chemical-transformation powder-in-tube (PIT) process. The obvious correlation between annealing temperature and phase transformation was observed. Annealing above 500 °C produced wire-core transformation from hexagonal to tetragonal phase. Furthermore the hexagonal phase completely transformed into the tetragonal phase by annealing at 1000 °C. With increasing annealing temperature, the superconducting property was dramatically improved, associated with the evolution of the tetragonal phase.
Molecular Beam Epitaxy Growth of Superconducting Ba1-xKxFe2As2and SmFeAs(O,F) Films
Authors: Ueda Shinya , Takeda Soichiro , Takano Shiro , Mitsuda Akihiro , Naito Michio
Published: December 2011

We report the molecular beam epitaxy (MBE) growth of the iron-based superconductors, Ba1-xKxFe2As2and SmFeAs(O,F). In the growth of Ba1-xKxFe2As2films, the key to incorporating volatile K in films is low-temperature (≤350 °C) growth in reduced As flux. The highestTcthus far obtained isTcon(Tcend) = 38.0 K (35.8 K). In the growth of superconducting SmFeAs(O,F), we adopted two methods. In the first method, we first grew pristine SmFeAsO films, and subsequently introduced F into the films by diffusion from an overlayer of SmF3. In the second method, we grew as-grown superconducting SmFeAs(O,F) films by coevaporating Sm, SmF3, Fe, and As. Thus far, better results have been obtained by the first F diffusion method. The films prepared by F diffusion showedTcon(Tcend) = 56.5 K (55.3 K), whereas the as-grown films showedTcon(Tcend) = 51.5 K (48.0 K).
Spin Hall Effect in Superconductors
Authors: Takahashi Saburo , Maekawa Sadamichi
Published: December 2011

Spin Hall effect in a superconductor is theoretically studied. The spin injection from a ferromagnet into a superconductor creates quasiparticle spin and charge currents in SC, which generate charge and spin currents in the transverse direction to accumulate spin and charge imbalance near the side edges of a superconductor. A giant enhancement of spin and charge accumulation signals in the side jump and skew scattering mechanisms of the spin Hall effect is predicted to occur at low temperatures in the superconducting state.
Short-Pulse Intrinsic Tunneling Spectroscopy in Bi2Sr2CaCu2O8+δunder Suppressed Self Heating
Authors: Suzuki Minoru , Takemura Ryota , Hamada Kenji , Ohmaki Masayuki , Watanabe Takao
Published: December 2011

Short-pulse tunneling spectroscopy on a time scale of 300 ns has been conducted using intrinsic Josephson junctions naturally built in the crystal structure of a slightly underdoped Bi2Sr2CaCu2O8+δ(Bi2212) by fabricating a very small and thin mesa of 6 nm in thickness and less than 5 µm in square width. The results are characterized by a pronounced superconducting peak at 79 meV accompanied by a broad pseudgap at a much higher energy of 125 meV, indicating discrete nature of both energy structures. The temperature rise due to self-heating in a small mesa is numerically calculated based on temperature-dependent thermal conductivity and specific heat for each constituent material. It is found that the temperature rise is less than 2 K for the present experiment, which reinforces that the tunneling spectra obtained represent the genuine superconducting properties of Bi2212.
Cooper-Pair Radiative Recombination in Semiconductor Heterostructures: Impact on Quantum Optics and Optoelectronics
Authors: Suemune Ikuo , Sasakura Hirotaka , Hayashi Yujiro , Tanaka Kazunori , Akazaki Tatsushi , Asano Yasuhiro , Inoue Ryotaro , Takayanagi Hideaki , Hanamura Eiichi , Huh Jae-Hoon , Hermannstädter Claus , Odashima Satoru , Kumano Hidekazu
Published: December 2011

The injection of Cooper pairs into a normal medium such as a semiconductor is known as the proximity effect at the superconductor/normal interface. We confirm this injection as well as the contribution of Cooper pairs to a drastic enhancement of inter-band optical transitions in semiconductor heterostructures. In this paper we investigate and clarify the relation of internal quantum efficiencies and radiative lifetimes in Cooper-pair light emitting diodes (CP-LEDs). A quantitative description of the dynamic photon generation processes is given, and the contribution of the Cooper-pair recombination relative to normal-electron recombination in CP-LEDs is discussed in detail.
Charge Injection Enhanced by Guest Material in Molecularly Doped Liquid Crystalline Thin Films
Authors: Nakano Kyohei , Iino Hiroaki , Usui Takayuki , Takayashiki Yukiko , Hanna Jun-ichi
Published: December 2011

We have investigated the charge injection into a host–guest type of molecularly doped liquid crystalline thin film in liquid crystal cells. A 2-phenylnaphthalene smectic liquid crystal of 2-(4'-octylphenyl)-6-dodecyloxynaphthalene was used as a host material and a diketopyrrolopyrrole derivative of 1,4-diketo-N,N '-dimethyl-3,6-bis(4-dodecyloxyphenyl) pyrrolo[3,4-c]pyrrole was used as a dopant material: the current–voltage characteristics of the thin films with Pt, indium–tin oxide (ITO), MgAg, and Al electrodes were measured and analyzed on the basis of the Schottky mechanism. By comparing the current–voltage characteristics, we determined the majority carriers dominating the current and estimated the barrier height for electrons and holes. We found that the barrier height was smaller than the energy difference between energy levels of the host liquid crystalline material and the work functions of electrode materials. We concluded that the current in the host–guest thin film was dominated by the guest material that has a narrow energy gap and is responsible for the charge injection into the host material.
Infrared Polarizer Fabrication by Imprinting on Sb–Ge–Sn–S Chalcogenide Glass
Authors: Yamada Itsunari , Yamashita Naoto , Tani Kunihiko , Einishi Toshihiko , Saito Mitsunori , Fukumi Kouhei , Nishii Junji
Published: December 2011

We fabricated infrared wire-grid polarizers consisting of a 500-nm pitch Al grating on a low toxic chalcogenide glass (Sb–Ge–Sn–S system) using the direct imprinting of subwavelength grating followed by a deposition of Al metal by thermal evaporation. To fabricate the subwavelength grating on a chalcogenide glass more easily, the sharp grating was formed on the mold surface. The fabricated polarizer with Al thickness of 130 nm exhibited a polarization function with a transverse magnetic transmittance greater than 60% in the 5–9 µm wavelength range, and an extinction ratio greater than 20 dB in 3.5–11 µm wavelength range. The extinction ratio of the element with Al wires of 180-nm thickness reached 27 dB at 5.4-µm wavelength. The polarizer can be fabricated at lower costs and simpler fabrication processes compared to conventional infrared polarizers.
Reconstructions on AlN Polar Surfaces under Hydrogen Rich Conditions
Authors: Akiyama Toru , Obara Daisuke , Nakamura Kohji , Ito Tomonori
Published: December 2011

Structures and stability of AlN(0001) and (0001̄) surfaces under hydrogen rich conditions are theoretically investigated by performing first-principles pseudopotential calculations. The calculated surface energies demonstrate that several hydrogen incorporated structures are stabilized depending on the chemical potentials of constituting elements. Using surface phase diagrams, which are obtained by comparing the calculated adsorption energy with vapor-phase chemical potentials, we find that H atoms tend to desorb from AlN(0001) surface even under high H2 pressures. In contrast, N–H bonds on AlN(0001̄) surface are found to be favorable over the wide range growth conditions. These results imply that the growth processes on AlN(0001) surface could be changed by growth conditions such as temperatures and pressures.