bluuebunny/crossref_metadata_2025 huggingface dataset:
Perioperative respiratory complications following awake and deep extubation in children undergoing adenotonsillectomy
Authors: Baijal Rahul G. , Bidani Sudha A. , Minard Charles G. , Watcha Mehernoor F.
Published: November 2014

Background

Perioperative respiratory complications after adenotonsillectomy (T&A) are common and have been described to occur more frequently in children below 3 years of age, those with cranio‐facial abnormalities, Down syndrome, obstructive sleep apnea, morbid obesity, and failure to thrive.

Aims

To investigate the association between awake vs deep tracheal extubation and perioperative respiratory conditions.

Results

The primary outcome was any perioperative respiratory complication. Major complications included the need for airway reinstrumentation, continuous or bi‐level positive airway pressure (CPAP or BiPAP) and ventilation, or pharmacologic intervention for managing airway obstruction. Minor respiratory complications included persistent hypoxemia defined as oxygen saturation (SpO2) <92% for ≥30 s or postoperative oxygen dependence for hypoxemia for ≥15 min. There was no statistically significant difference in the incidence of any perioperative respiratory complication in children undergoing an awake vs deep extubation (18.5% and 18.9% for awake and deep extubation, respectively (P = 0.93)). Only low weight (≤14 kg) was associated with increased perioperative respiratory complications (P = 0.005). In this study, factors found not to be statistically significant with perioperative respiratory complications included age; presence of Down syndrome, cranio‐facial abnormality, or cerebral palsy; obstructive sleep apnea confirmed by polysomnography; diagnosis of obstructive sleep apnea by clinical history; presence of an upper respiratory tract infection (URI) within 2 weeks of presentation; history of reactive airway disease; status at extubation; endtidal sevoflurane and carbon dioxide concentrations at extubation; total intraoperative opioids administered in morphine equivalents (mg·kg−1); administration of propofol at extubation; and intraoperative administration of an anticholinergic drug.

Conclusions

There was no difference in the incidence of perioperative respiratory complications in children undergoing a T&A following an awake vs deep extubation. Only weight ≤14 kg was associated with increased perioperative respiratory complications.
Integration of BpMADS4 on various linkage groups improves the utilization of the rapid cycle breeding system in apple
Authors: Weigl Kathleen , Wenzel Stephanie , Flachowsky Henryk , Peil Andreas , Hanke Magda‐Viola
Published: November 2014

Rapid cycle breeding in apple is a new approach for the rapid introgression of agronomically relevant traits (e.g. disease resistances) from wild apple species into domestic apple cultivars (Malus × domestica Borkh.). This technique drastically shortens the long‐lasting juvenile phase of apple. The utilization of early‐flowering apple lines overexpressing the BpMADS4 gene of the European silver birch (Betula pendula Roth.) in hybridization resulted in one breeding cycle per year. Aiming for the selection of non‐transgenic null segregants at the end of the breeding process, the flower‐inducing transgene and the gene of interest (e.g. resistance gene) that will be introgressed by hybridization need to be located on different chromosomes. To improve the flexibility of the existing approach in apple, this study was focused on the development and characterization of eleven additional BpMADS4 overexpressing lines of four different apple cultivars. In nine lines, the flowering gene was mapped to different linkage groups. The differences in introgressed T‐DNA sequences and plant genome deletions post‐transformation highlighted the unique molecular character of each line. However, transgenic lines demonstrated no significant differences in flower organ development and pollen functionality compared with non‐transgenic plants. Hybridization studies using pollen from the fire blight‐resistant wild species accession Malus fusca MAL0045 and the apple scab‐resistant cultivar ‘Regia’ indicated that BpMADS4 introgression had no significant effect on the breeding value of each transgenic line.
Cotton (Gossypium hirsutum) 14‐3‐3 proteins participate in regulation of fibre initiation and elongation by modulating brassinosteroid signalling
Authors: Zhou Ying , Zhang Ze‐Ting , Li Mo , Wei Xin‐Zheng , Li Xiao‐Jie , Li Bing‐Ying , Li Xue‐Bao
Published: November 2014

Cotton (Gossypium hirsutum) fibre is an important natural raw material for textile industry in the world. Understanding the molecular mechanism of fibre development is important for the development of future cotton varieties with superior fibre quality. In this study, overexpression of Gh14‐3‐3L in cotton promoted fibre elongation, leading to an increase in mature fibre length. In contrast, suppression of expression of Gh14‐3‐3L, Gh14‐3‐3e and Gh14‐3‐3h in cotton slowed down fibre initiation and elongation. As a result, the mature fibres of the Gh14‐3‐3 RNAi transgenic plants were significantly shorter than those of wild type. This ‘short fibre’ phenotype of the 14‐3‐3 RNAi cotton could be partially rescued by application of 2,4‐epibrassinolide (BL). Expression levels of the BR‐related and fibre‐related genes were altered in the Gh14‐3‐3 transgenic fibres. Furthermore, we identified Gh14‐3‐3 interacting proteins (including GhBZR1) in cotton. Site mutation assay revealed that Ser163 in GhBZR1 and Lys51/56/53 in Gh14‐3‐3L/e/h were required for Gh14‐3‐3‐GhBZR1 interaction. Nuclear localization of GhBZR1 protein was induced by BR, and phosphorylation of GhBZR1 by GhBIN2 kinase was helpful for its binding to Gh14‐3‐3 proteins. Additionally, 14‐3‐3‐regulated GhBZR1 protein may directly bind to GhXTH1 and GhEXP promoters to regulate gene expression for responding rapid fibre elongation. These results suggested that Gh14‐3‐3 proteins may be involved in regulating fibre initiation and elongation through their interacting with GhBZR1 to modulate BR signalling. Thus, our study provides the candidate intrinsic genes for improving fibre yield and quality by genetic manipulation.
Help seeking and social competence mediate the parental attachment–college student adjustment relation
Authors: HOLT LAURA J.
Published: November 2014

This short‐term longitudinal study investigated whether attitudes about academic help seeking, social competence, and self‐compassion mediated the relations between parental attachment and college student adjustment. Two hundred and four first‐year students completed measures of parental attachment and the proposed mediators at the beginning of their first semester. At the end of the semester, students reported on their academic, social, and personal/emotional adjustment. Results showed that attitudes about academic help seeking mediated the attachment–academic adjustment relation and social competence mediated the attachment–social adjustment relation. Personal/emotional adjustment largely was predicted by initial personal/emotional adjustment. These findings suggest that help‐seeking attitudes and social competence could be fruitful targets of intervention for personnel working with college students who have strained parental relationships.
Immunization of mice with Plasmodium TCTP delays establishment of Plasmodium infection
Authors: Taylor K. J. , Van T. T. H. , MacDonald S. M. , Meshnick S. R. , Fernley R. T. , Macreadie I. G. , Smooker P. M.
Published: November 2014

Translationally controlled tumour protein (TCTP) may play an important role in the establishment or maintenance of parasitemia in a malarial infection. In this study, the potential of TCTP as a malaria vaccine was investigated in two trials. In the initial vaccine trial, Plasmodium falciparum TCTP (PfTCTP) was expressed in Saccharomyces cerevisiae and used to immunize BALB/c mice. Following challenge with Plasmodium yoelii YM, parasitemia was significantly reduced during the early stages of infection. In the second vaccine trial, the TCTP from P. yoelii and P. berghei was expressed in Escherichia coli and used in several mouse malaria models. A significant reduction in parasitemia in the early stages of infection was observed in BALB/c mice challenged with P. yoelii YM. A significantly reduced parasitemia at each day leading up to a delayed and reduced peak parasitemia was also observed in BALB/c mice challenged with the nonlethal Plasmodium chabaudi (P.c.) chabaudi AS. These results suggest that TCTP has an important role for parasite establishment and may be important for pathogenesis.
Artificial leaf aids analysis of chlorophyll fluorescence and P700 absorbance in studies involving microalgae
Authors: Qiao Hongjin , Fan Xiao , Xu Dong , Ye Naihao , Wang Jiying , Cao Shaona
Published: November 2014

Measuring chlorophyll fluorescence and P700 absorbance has been widely used to study photosynthesis in both terrestrial plants and algae. However, in order to apply these measurement techniques to study microalgae, a concentrated suspension of algae, which is usually prepared by centrifugation, is required. In this study, instead of using centrifugation, we concentrated microalgae on a nitrocellulose membrane using filtration to create an ‘artificial leaf’ before analysis. Overall, we were able to generate values of the appropriate photosynthetic parameters that were comparable to those obtained when chlorophyll fluorescence and P700 absorbance were measured following centrifugation. There were no statistically significant differences (P > 0.05) between the artificial leaf method and the traditional cuvette method for determining chlorophyll fluorescence or P700 absorbance at appropriate chlorophyll concentrations. We were also able to reduce background noise by using a filter membrane as a carrier. Therefore, an artificial leaf has the potential to be a valuable tool for phycologists interested in studying microalgal photosynthesis by enabling them to eliminate tedious centrifugation steps. In addition, fluorometers commonly used for studying the leaves of higher plants will also be suitable for studying microalgae.
Diabetes mellitus onset in geriatric patients: does long‐term atypical antipsychotic exposure increase risk?
Authors: Abitbol Roza , Rej Soham , Segal Marilyn , Looper Karl J.
Published: November 2014

Background

Diabetes mellitus (DM) in common in adults using psychotropic medications. However, it remains largely unknown whether there is an additional risk of diabetes mellitus (DM) in elderly psychiatric outpatients, particularly those with long‐term exposure to atypical antipsychotics (AP).

Methods

In this retrospective longitudinal study, 61 atypical AP‐exposed and 64 atypical AP‐unexposed geriatric psychiatric patients were compared to a group of 200 psychotropic‐naïve controls. Our main composite outcome was diabetes incidence over a 4‐year period, defined by fasting blood glucose ≥ 7.0 mmol/L or a new‐onset oral hypoglycaemic or insulin prescription during the 4‐year period.

Results

The 4‐year incidence of DM did not differ significantly between groups: 12.3%, 6.7%, and 11.9% in the atypical AP‐exposed, atypical AP‐unexposed, and control groups, respectively (χ2 = 1.40, P = 0.50). Depression and antidepressant, cholinesterase inhibitor, and valproate use were independently associated with increases in fasting glucose. However, hyperglycaemia and hypoglycaemic prescriptions were not more common in geriatric psychiatric patients.

Conclusions

DM does not appear to be more common in geriatric psychiatric patients than similarly aged controls and is not more common in atypical AP users. However, depression and antidepressant, cholinesterase inhibitor, and valproate use may increase fasting glucose levels, and the clinical significance of this warrants further investigation. Nonetheless, given the rates of untreated and undertreated fasting hyperglycaemia in both our geriatric psychiatric and control samples (>10% of all patients), we recommend regular screening for DM in these populations.
ERP and pupil responses to deviance in an oddball paradigm
Authors: Kamp Siri‐Maria , Donchin Emanuel
Published: November 2014

We investigated the relationship between, and functional significance of, P300, novelty P3, and the pupil dilation response (PDR). Subjects categorized stimuli including (a) words of a frequent category, (b) words of an infrequent category (14%), and (c) pictures of the frequent category (“novels”; 14%). The P300 and novelty P3 were uncorrelated with the PDR and differed in their response to experimental manipulation. Therefore, although the three physiological responses often co‐occur, they appear to each manifest a distinct function: The PDR may be more closely linked to aspects of behavioral responding than the event‐related potentials. Within participants, P300 and PDR latencies accounted for unique portions of the reaction time variance, and amplitudes of all three responses were larger for stimuli recalled on a subsequent test, compared to not recalled. We discuss the possibility that all three responses reflect norepinephric input from the locus coeruleus.
Suicidal Behavior Outcomes of Childhood Sexual Abuse: Longitudinal Study of Adjudicated Girls
Authors: Rabinovitch Sara M. , Kerr David C. R. , Leve Leslie D. , Chamberlain Patricia
Published: November 2014

Childhood sexual abuse (CSA) histories are prevalent among adolescent girls in the juvenile justice system (JJS) and may contribute to their high rates of suicidal behavior. Among 166 JJS girls who participated in an intervention trial, baseline CSA and covariates were examined as predictors of suicide attempt and nonsuicidal self‐injury (NSSI) reported at long‐term follow‐up (7–12 years later). Early forced CSA was related to lifetime suicide attempt and NSSI history and (marginally) to postbaseline attempt; effects were not mediated by anxiety or depressive symptoms. Findings suggest that earlier victimization and younger entry into JJS are linked with suicide attempt and NSSI.
Influence of farm yard manure, poultry manure and forest litter on copper solubility in soil and uptake by Phaseolus vulgaris
Authors: Senkondo Y. H. , Tack F. M. G. , Semu E.
Published: November 2014

Long term and intensive use of copper‐based fungicides on coffee farms may contaminate soils with copper. The legacy of copper pollution may pose the risk of contaminating food crops cultivated on these soils. A randomized block design field experiment at Kilimanjaro, Tanzania was designed to investigate the effects of different application rates of cattle manure, poultry manure and forest litter on aqua regia, EDTA and CaCl2 extractable copper in soils and copper uptake by bean plants grown on this long‐term copper‐contaminated soil (more than 50 yr of copper application). It was important to examine the potential of the organic amendments in mobilizing or immobilizing copper and assess the risks of contaminating bean crops at a farm, where the application of organic amendments was common practice. At harvest, rhizosphere soils were collected and analysed. The soils were found to have large concentrations of copper, greatly exceeding international standard levels. Poultry manure applied at 40 tons/ha significantly increased CaCl2 extractable copper compared with the control treatment. Organic carbon, cation exchange capacity, EDTA extractable copper, aqua regia extractable copper and copper concentrations in bean seeds or leaves were not significantly changed by the organic matter treatments. The concentration of copper was significantly less in bean seeds than in bean leaves (P < 0.01). The bean plants did not take up excessive quantities of copper, and therefore, the risk of copper contamination of bean crops in this farm appears to be small.
Ligand‐Induced Compaction of the PEX5 Receptor‐Binding Cavity Impacts Protein Import Efficiency into Peroxisomes
Authors: Fodor Krisztián , Wolf Janina , Reglinski Katharina , Passon Daniel M. , Lou Ye , Schliebs Wolfgang , Erdmann Ralf , Wilmanns Matthias
Published: November 2014

Peroxisomes entirely rely on the import of their proteome across the peroxisomal membrane. Recognition efficiencies of peroxisomal proteins vary by more than 1000‐fold, but the molecular rationale behind their subsequent differential import and sorting has remained enigmatic. Using the protein cargo alanine‐glyoxylate aminotransferase as a model, an unexpected increase from 34 to 80% in peroxisomal import efficiency of a single‐residue mutant has been discovered. By high‐resolution structural analysis, we found that it is the recognition receptor PEX5 that adapts its conformation for high‐affinity binding rather than the cargo protein signal motif as previously thought. During receptor recognition, the binding cavity of the receptor shrinks to one third of its original volume. This process is impeded in the wild‐type protein cargo because of a bulky side chain within the recognition motif, which blocks contraction of the PEX5 binding cavity. Our data provide a new insight into direct protein import efficiency by removal rather than by addition of an apparent specific sequence signature that is generally applicable to peroxisomal matrix proteins and to other receptor recognition processes.
The impact of whole blood processing and freezing conditions on the quality of therapeutic plasma prepared from whole blood
Authors: Runkel Stefan , Hitzler Walter E. , Hellstern Peter
Published: November 2014

Background

The quality of whole blood (WB)‐derived plasma preparations has been the subject of several studies, but there has been a lack of robust, comparative data for the different methods of processing and freezing.

Study Design and Methods

Six WB‐derived plasma units were pooled and split (n = 16) and frozen within either 8 or 24 hours after WB collection, stored at 4°C or at room temperature (RT), and then frozen either slowly at −20°C or rapidly to below −30°C. Plasma units were tested for fibrinogen, Factor (F)V, FVII, FVIII, FXI, and von Willebrand factor (VWF), protein C (PC), protein S (PS) activity and free PS, prothrombin time, and partial thromboplastin time.

Results

FVIII was reduced by 9% to 19% after having been stored for 24 hours irrespective of storage temperature. Slow freezing (SF) reduced FVIII by 17% to 25% compared to rapid freezing (RF) to below −30°C. Storage temperature, but not 24‐hour storage, decreased PS activity by 20% to 28%. PS activity was 8% to 17% lower in plasma units frozen slowly compared to RF. Storage and freezing had no influence on free PS. SF caused small losses of FVII and FXI activity.

Conclusion

Twenty‐four‐hour hold at RT and SF both reduce FVIII levels below 70 U/dL in many plasma units. PS activity is affected substantially by storage temperature and SF, but free PS is not. With regard to plasma quality, freezing to below −30°C within 1 hour is superior to SF at −20°C.
In vitro comparison of cryopreserved and liquid platelets: potential clinical implications
Authors: Johnson Lacey , Reade Michael C. , Hyland Ryan A. , Tan Shereen , Marks Denese C.
Published: November 2014

Background

Platelet (PLT) concentrates can be cryopreserved in dimethyl sulfoxide (DMSO) and stored at −80°C for 2 years. These storage conditions improve availability in both rural and military environments. Previous phenotypic and in vitro studies of cryopreserved PLTs are limited by comparison to fresh liquid‐stored PLTs, rather than PLTs stored over their clinically relevant shelf life. Further, nothing is known of the effect of reconstituting cryopreserved PLTs in plasma stored at a variety of clinically relevant temperatures.

Study Design and Methods

Apheresis PLTs were either stored at room temperature for 5 days or cryopreserved at −80°C with 5% DMSO. Cryopreserved PLTs were thawed at 37°C and reconstituted in plasma (stored at different temperatures) and compared to fresh and expired liquid‐stored PLTs. In vitro assays were performed to assess glycoprotein expression, PLT activity, microparticle content, and function.

Results

Compared to liquid PLTs over storage, cryopreserved PLTs had reduced expression of the key glycoprotein receptors GPIbα and GPIIb. However, the proportion of PLTs expressing activation markers CD62P and CD63 was similar between cryopreserved and liquid‐stored PLTs at expiry. Cryopreserved PLT components contained significantly higher numbers of phosphatidylserine‐ and tissue factor–positive microparticles than liquid‐stored PLTs, and these microparticles reduced the time to clot formation and increased thrombin generation.

Conclusion

There are distinct differences between cryopreserved and liquid‐stored PLTs. Cryopreserved PLTs also have an enhanced hemostatic activity. Knowledge of these in vitro differences will be essential to understanding the outcomes of a clinical trial comparing cryopreserved PLTs and liquid PLTs stored for various durations.
Factors affecting the distribution and associated species of Malva parviflora in the Nile Delta, Egypt
Authors: Shehata Hanaa S. , Galal Tarek M.
Published: November 2014

Malva parviflora (little mallow) is a wild herb with agricultural importance in Egypt, where it is cultivated as a food crop. The main objective of the present work was to study the distribution and common associated species of the arable weed, M. parviflora, in the Nile Delta, Egypt. In addition, the diversity and behavior of the common species along the prevailing environmental conditions were assessed. Fifty stands, representing five common habitats (crop fields, orchards, canals, drains and roadsides), were selected. Eighty‐five species and one variety (50 annuals and 36 perennials) were recorded. Therophytes dominated the other life forms and biregional taxa contributed the highest chorological elements. Malva parviflora is a therophytic plant that has a Mediterranean distribution intermingled with Irano‐Turanian elements. Moreover, the highest coverage percentage of M. parviflora was recorded in the canal banks. Four vegetation groups that represented the distinct habitats were produced by the application of a two‐way indicator species analysis and a detrended correspondence analysis as a classification and ordination technique, respectively. Vegetation group C, which inhabited the crop fields, was the most diverse. A canonical correspondence analysis indicated that calcium carbonate, organic carbon, carbonate, potassium and the potassium adsorption ratio and electrical conductivity are the most effective soil variables on the distribution of M. parviflora and its associated species in the different habitats. It was found that M. parviflora was affected greatly by calcium carbonate, sand and magnesium. In addition, it was significantly associated with soil bicarbonate. Such a study could help in managing this important agricultural weed.
Thermal Performance of Nanofluid Charged Heat Pipe With Phase Change Material for Electronics Cooling
Authors: Chougule Sandesh S. , Sahu S. K.
Published: November 2014

The paper reports the thermal performance of a nanofluid (MCNT/water) charged heat pipe with phase change material (PCM) as energy storage material (ESM) for electronic cooling. The adiabatic section of heat pipe is covered by the PCM stored in a container made of acrylic material. Here, paraffin is used as PCM. PCM can absorb and release thermal energy depending upon the fluctuations in the heating load. Tests are conducted to obtain the temperature distributions in PCM during charge/discharge processes. Present study utilizes two different ESM (water and paraffin), different fan speeds and heating powers in the PCM cooling module. The cooling module with heat pipe and paraffin as ESM found to save higher fan power consumption compared to the cooling module that utilities only a heat pipe.
A Computational Study of Dry Static Friction Between Elastoplastic Surfaces Using a Statistically Homogenized Microasperity Model
Authors: Sista Bhargava , Vemaganti Kumar
Published: November 2014

Friction is a complex phenomenon that arises from the interaction of deforming surface microasperities and adhesive forces at very small length scales. In this work, we use a computational model to understand the effects of various physical parameters on the friction response between two similar linearly elastic-perfectly plastic surfaces. The main ingredients of the computational model are a statistical model of the surface based on a Gaussian autocorrelation function (ACF), a parametric representation of the normal and shear responses of a single microasperity, and a statistical homogenization procedure to compute the overall friction response. The surfaces are assumed to be isotropic in nature. We employ this computational model to develop constitutive relationships for the friction force and coefficient of friction for Aluminum 6061 and stainless steel surfaces. We study the effects of various quantities such as surface roughness, material properties, normal load, and adhesive forces on the overall friction response. Our results show that the model is able to capture a wide variety of friction responses. Our results also suggest that the root mean squared (RMS) roughness of the surface alone is insufficient to describe the friction characteristics of a surface, and that an additional parameter is needed. We propose one such parameter, the aspect ratio, which is the ratio of the RMS roughness to the correlation length.
Damage Localization in Composite Structures Using Nonlinear Vibration Response Properties
Authors: Underwood Sara S. , Meyer Janette J. , Adams Douglas E.
Published: November 2014

Subsurface damage in composite materials is difficult to detect using visual techniques, and other current inspection methods lack the ability to perform quick, wide-area inspections without the need for reference signatures or baseline measurements. This paper presents a method for detecting and locating subsurface damage in composite materials without historical reference measurements by considering the nonlinear behavior of the material in the vicinity of damage. Nonlinear behavior is identified by comparing frequency response functions measured at different input amplitudes. It will be shown that the nonlinear behavior of the material is most evident in the areas nearest to the damage. The proposed inspection method is demonstrated both analytically and experimentally. First, a finite element model of a sandwich beam is developed using Bernoulli–Euler beam elements to represent each layer of the beam and springs to represent the interface between the layers. A bilinear stiffness nonlinearity is simulated to represent disbond damage between the top and core layers of the beam. The simulated disbond damage is localized by identifying degrees of freedom which indicate significant nonlinear response through a comparison of frequency response functions measured at various input amplitudes. Next, the method is demonstrated experimentally by identifying disbond damage in a fiberglass sandwich panel. A three-dimensional scanning laser vibrometer is used to measure the forced frequency response of the panel in its damaged state as it is excited at two or more amplitudes of excitation by a piezoelectric actuator. Comparisons of the frequency response functions measured at different input amplitudes show that the subsurface damage introduces nonlinear behavior which resembles a bilinear stiffness nonlinearity, and the differences in the frequency response functions are largest in the vicinity of the damage location. In addition, it was found that improved localization of the damage is achieved by investigating the response at higher frequencies. This work has application as a nondestructive method for detecting and locating subsurface damage in composite materials and, by using a laser vibrometer for noncontact measurement, allows for quick, wide-area inspection of composite materials without the need for reference signatures or baseline measurements.
Fluidic Flexible Matrix Composite Vibration Absorber for a Cantilever Beam
Authors: Zhu Bin , Rahn Christopher D. , Bakis Charles E.
Published: November 2014

Fluidic flexible matrix composite (F2MC) tubes with resonant fluidic circuits can absorb vibration at a specific frequency when bonded to flexible structures. The transverse structural vibration applies cyclic axial strain to the F2MC tubes. The anisotropic elastic properties of the composite tube amplify the axial strain to produce large internal volume change. The volume change forces fluid through a flow port and into an external accumulator. The fluid inertance in the flow port (inertia track) and the stiffness of the accumulator are analogous to the vibration absorbing mass and stiffness in a conventional tuned vibration absorber. An analytical model of an F2MC-integrated cantilever beam is developed based on Euler–Bernoulli beam theory and Lekhnitskii's solution for anisotropic layered tubes. The collocated tip force to tip displacement analytical transfer function of the coupled system is derived. Experimental testing is conducted on a laboratory-scale F2MC beam structure that uses miniature tubes and fluidic components. The resonant peak becomes an absorber notch in the frequency response function (FRF) if the inertia track length is properly tuned. Tuning the fluid bulk modulus and total flow resistance in the theoretical model produces results that match the experiment well, predicting a magnitude reduction of 35 dB at the first resonance using an F2MC absorber. Based on the experimentally validated model, analysis results show that the cantilever beam vibration can be reduced by more than 99% with optimally designed tube attachment points and flow port geometry.
Dynamic Analysis of a Series Iwan Model Derived From a Continuous Frictional Interface
Authors: Deshmukh Dinar , Berger Edward
Published: November 2014

Reduced-order models for characterizing friction interfaces have been investigated for the last 75 years. Recent work has been focused on microslip formulations of the interface behavior, where a continuous interface is approximated with a multipoint contact model. A novel multipoint friction model is presented in this work, which is entirely derived from a shear-lag approach to resolve the kinematic state of the friction interface under the presence of tangential loading. Both static and dynamic loading conditions are analyzed and comparisons are drawn between the continuous and discrete models. The series Iwan model presented in this work differentiates between the elastic and friction components of the interface displacement, both parameters being calibrated using material properties and model geometry. The response characteristics of the series Iwan model under dynamic loading conditions are also investigated. The series Iwan model is in good agreement with the shear-lag approach for results such as propagation of the slip zone with increasing pullout force. The transient response of the structural mass and the kinematic states of the Iwan elements are convergent with increasing model order. A direct physical correlation between the response of the series Iwan model and kinematics of the continuous interface is developed, which greatly enhances the appeal of this particular model for simulating interface phenomena.
Effect of UV curing time on physical and electrical properties and reliability of low dielectric constant materials
Authors: Kao Kai-Chieh , Chang Wei-Yuan , Chang Yu-Min , Leu Jihperng , Cheng Yi-Lung
Published: November 2014

This study comprehensively investigates the effect of ultraviolet (UV) curing time on the physical, electrical, and reliability characteristics of porous low-k materials. Following UV irradiation for various periods, the depth profiles of the chemical composition in the low-k dielectrics were homogeneous. Initially, the UV curing process preferentially removed porogen-related CHx groups and then modified Si-CH3 and cage Si-O bonds to form network Si-O bonds. The lowest dielectric constant (k value) was thus obtained at a UV curing time of 300 s. Additionally, UV irradiation made porogen-based low-k materials hydrophobic and to an extent that increased with UV curing time. With a short curing time (<300 s), porogen was not completely removed and the residues degraded reliability performance. A long curing time (>300 s) was associated with improved mechanical strength, electrical performance, and reliability of the low-k materials, but none of these increased linearly with UV curing time. Therefore, UV curing is necessary, but the process time must be optimized for porous low-k materials on back-end of line integration in 45 nm or below technology nodes.
Ordered array of Ga droplets on GaAs(001) by local anodic oxidation
Authors: Sala Elisa M. , Bollani Monica , Bietti Sergio , Fedorov Alexey , Esposito Luca , Sanguinetti Stefano
Published: November 2014

The authors present a procedure to obtain uniform, ordered arrays of Ga droplets on GaAs(001) substrates. The growth process relies on an interplay between the substrate patterning, in form of a two dimensional array of nanoholes periodically modulated obtained via local anodic oxidation, and self-assembly of Ga droplets in a molecular beam epitaxy environment. The formation of site controlled Ga droplets, characterized by atomic force microscopy, is the outcome of the combined effects of capillary condensation and nucleation kinetics.
Acoustic radiation force and torque on an absorbing compressible particle in an inviscid fluid
Authors: Silva Glauber T.
Published: November 2014

Exact formulas of the acoustic radiation force and torque exerted by an arbitrary time-harmonic wave on an absorbing compressible particle that is suspended in an inviscid fluid are presented. It is considered that the particle diameter is much smaller than the incident wavelength, i.e., the so-called Rayleigh scattering limit. Moreover, the particle absorption assumed here is due to the attenuation of compressional waves only. Shear waves inside and outside the particle are neglected, since the inner and outer viscous boundary layer of the particle are supposed to be much smaller than the particle radius. The obtained radiation force formulas are used to establish the trapping conditions of a particle by a single-beam acoustical tweezer based on a spherically focused ultrasound transducer. In this case, it is shown that the particle absorption has a pivotal role in single-beam trapping at the transducer focal region. Furthermore, it is found that only the first-order Bessel vortex beam can generate the radiation torque on a small particle. In addition, numerical evaluation of the radiation force and torque exerted on a benzene and an olive oil droplet suspended in water are presented and discussed.
Phase effects in masking by harmonic complexes: Detection of bands of speech-shaped noise
Authors: Deroche Mickael L. D. , Culling John F. , Chatterjee Monita
Published: November 2014

When phase relationships between partials of a complex masker produce highly modulated temporal envelopes on the basilar membrane, listeners may detect speech information from temporal dips in the within-channel masker envelopes. This source of masking release (MR) is however located in regions of unresolved masker partials and it is unclear how much of the speech information in these regions is really needed for intelligibility. Also, other sources of MR such as glimpsing in between resolved masker partials may provide sufficient information from regions that disregard phase relationships. This study simplified the problem of speech recognition to a masked detection task. Target bands of speech-shaped noise were restricted to frequency regions containing either only resolved or only unresolved masker partials, as a function of masker phase relationships (sine or random), masker fundamental frequency (F0) (50, 100, or 200 Hz), and masker spectral profile (flat-spectrum or speech-shaped). Although masker phase effects could be observed in unresolved regions at F0s of 50 and 100 Hz, it was only at 50-Hz F0 that detection thresholds were ever lower in unresolved than in resolved regions, suggesting little role of envelope modulations for harmonic complexes with F0s in the human voice range and at moderate level.
Age mitigates the correlation between cognitive processing speed and audio-visual asynchrony detection in speech
Authors: Alm Magnus , Behne Dawn
Published: November 2014

Cognitive processing speed, hearing acuity, and audio-visual (AV) experience have been suggested to influence AV asynchrony detection. Whereas the influence of hearing acuity and AV experience have been explored to some extent, the influence of cognitive processing speed on perceived AV asynchrony has not been directly tested. Therefore, the current study investigates the relationship between cognitive processing speed and AV asynchrony detection in speech and, with hearing acuity controlled, assesses whether age-related AV experience mitigates the strength of this relationship. The cognitive processing speed and AV asynchrony detection by 20 young adults (20–30 years) and 20 middle-aged adults (50–60 years) were measured using auditory, visual and AV recognition reaction time tasks, and an AV synchrony judgment task. Strong correlations between audio, visual, and AV reaction times and AV synchrony window size were found for young adults, but not for middle-aged adults. These findings suggest that although cognitive processing speed influences AV asynchrony detection in speech, the strength of the relationship is seemingly reduced by AV experience.
The focal index as a singular metric for beamforming effectiveness
Authors: Kelly Matthew R. , Amuso Vincent J. , Eddins David A. , Borkholder David A.
Published: November 2014

Hearing-impaired individuals frequently cite intelligibility problems in multi-talker environments. Microphone arrays performing time-delay beamforming address conditions of poor signal-to-noise ratio by spatially filtering incoming sound. Existing beam pattern metrics including peak side lobe level, integrated side lobe level, beamwidth, and planar directivity index fail to quantitatively capture all elements essential for improving speech intelligibility in multi-talker situations. The focal index (FI) was developed to address these deficiencies. Simulations were performed to exemplify the robust nature of the FI and to demonstrate the utility of this metric for driving array parameter selection. Beam patterns were generated and the metrics were calculated and evaluated against the strict unidirectional requirements for the array. Array performance was assessed by human subjects in a speech recognition task that incorporated competing speech from multiple locations. Simulations of array output were presented under conditions differing in array sparsity. The resulting human subject data were used to demonstrate the linear relationship (R2 > 0.975) between speech-intelligibility-weighted FI (SII-FI) and the signal-to-noise ratio thresholds for 20% and 80% correct responses. Data indicate that the FI and SII-FI are robust singular metrics for determining the effectiveness of the array.
Analysis of vibratory states in phonation using spectral features of the electroglottographic signal
Authors: Selamtzis Andreas , Ternström Sten
Published: November 2014

The vocal folds can oscillate in several different ways, manifest to practitioners and clinicians as “registers” or “mechanisms,” of which the two most often considered are modal voice and falsetto voice. Here these will be taken as instances of different “vibratory states,” i.e., distinct quasi-stationary patterns of vibration of the vocal folds. State transitions are common in biomechanical nonlinear oscillators, and they are often abrupt and impossible to predict exactly. Therefore, vibratory states are a source of confounding variation, for instance when acquiring a voice range profile (VRP). In the quest for a state-based, non-invasive VRP, a semi-automatic method based on the short-term spectrum of the electroglottographic (EGG) signal was developed. The method identifies rapid vibratory state transitions, such as the modal-falsetto switch, and clusters the EGG data based on their similarities in the relative levels and phases of the lower frequency components. Productions of known modal and falsetto voice were accurately clustered by a Gaussian mixture model. When mapped into the VRP, this EGG-based clustering revealed connected regions of different vibratory sub-regimes in both modal and falsetto.
A cross-dialectal acoustic comparison of vowels in Northern and Southern British English
Authors: Williams Daniel , Escudero Paola
Published: November 2014

This study compares the duration and first two formants (F1 and F2) of 11 nominal monophthongs and five nominal diphthongs in Standard Southern British English (SSBE) and a Northern English dialect. F1 and F2 trajectories were fitted with parametric curves using the discrete cosine transform (DCT) and the zeroth DCT coefficient represented formant trajectory means and the first DCT coefficient represented the magnitude and direction of formant trajectory change to characterize vowel inherent spectral change (VISC). Cross-dialectal comparisons involving these measures revealed significant differences for the phonologically back monophthongs /ɒ, ɔː, ʊ, uː/ and also /зː/ and the diphthongs /eɪ, əʊ, aɪ, ɔɪ/. Most cross-dialectal differences are in zeroth DCT coefficients, suggesting formant trajectory means tend to characterize such differences, while first DCT coefficient differences were more numerous for diphthongs. With respect to VISC, the most striking differences are that /uː/ is considerably more diphthongized in the Northern dialect and that the F2 trajectory of /əʊ/ proceeds in opposite directions in the two dialects. Cross-dialectal differences were found to be largely unaffected by the consonantal context in which the vowels were produced. The implications of the results are discussed in relation to VISC, consonantal context effects and speech perception.
Interaural-phase discrimination in notched noise
Authors: Nitschmann Marc , Verhey Jesko L.
Published: November 2014

Discrimination thresholds for the interaural-phase difference (IPD) of a 500-Hz sinusoid were measured in the presence of a diotic notched-noise masker as a function of notch width. The reference sinusoid had zero IPD. The level was set to 3 dB above the individual masked threshold for the diotic sinusoid at the respective notch width. Just-noticeable IPDs increased from about 20° for notch widths up to 100 Hz to 100° at the largest notch width of 800 Hz. Model simulations show that the data are consistent with the equalization-cancellation theory, if effectively wider binaural filters are assumed.
Stability analysis and design of time-domain acoustic impedance boundary conditions for lined duct with mean flow
Authors: Liu Xin , Huang Xun , Zhang Xin
Published: November 2014

This work develops the so-called compensated impedance boundary conditions that enable stable time domain simulations of sound propagation in a lined duct with uniform mean flow, which has important practical interest for noise emission by aero-engines. The proposed method is developed analytically from an unusual perspective of control that shows impedance boundary conditions act as closed-loop feedbacks to an overall duct acoustic system. It turns out that those numerical instabilities of time domain simulations are caused by deficient phase margins of the corresponding control-oriented model. A particular instability of very low frequencies in the presence of steady uniform background mean flow, in addition to the well known high frequency numerical instabilities at the grid size, can be identified using this analysis approach. Stable time domain impedance boundary conditions can be formulated by including appropriate phaselead compensators to achieve desired phase margins. The compensated impedance boundary conditions can be simply designed with no empirical parameter, straightforwardly integrated with ordinary linear acoustic models, and efficiently calculated with no need of resolving sheared boundary layers. The proposed boundary conditions are validated by comparing against asymptotic solutions of spinning modal sound propagation in a duct with a hard-soft interface and reasonable agreement is achieved.
Audio-visual interaction and perceptual assessment of water features used over road traffic noise
Authors: Galbrun Laurent , Calarco Francesca M. A.
Published: November 2014

This paper examines the audio-visual interaction and perception of water features used over road traffic noise, including their semantic aural properties, as well as their categorization and evocation properties. The research focused on a wide range of small to medium sized water features that can be used in gardens and parks to promote peacefulness and relaxation. Paired comparisons highlighted the inter-dependence between uni-modal (audio-only or visual-only) and bi-modal (audio-visual) perception, indicating that equal attention should be given to the design of both stimuli. In general, natural looking features tended to increase preference scores (compared to audio-only paired comparison scores), while manmade looking features decreased them. Semantic descriptors showed significant correlations with preferences and were found to be more reliable design criteria than physical parameters. A principal component analysis identified three components within the nine semantic attributes tested: “emotional assessment,” “sound quality,” and “envelopment and temporal variation.” The first two showed significant correlations with audio-only preferences, “emotional assessment” being the most important predictor of preferences, and its attributes naturalness, relaxation, and freshness also being significantly correlated with preferences. Categorization results indicated that natural stream sounds are easily identifiable (unlike waterfalls and fountains), while evocation results showed no unique relationship with preferences.
Relative variance of the mean-squared pressure in multimode media: Rehabilitating former approaches
Authors: Monsef Florian , Cozza Andrea , Rodrigues Dominique , Cellard Patrick , Durocher Jean-Noel
Published: November 2014

The commonly accepted model for the relative variance of transmission functions in room acoustics, derived by Weaver, aims at including the effects of correlation between eigenfrequencies. This model is based on an analytical expression of the relative variance derived by means of an approximated correlation function. The relevance of the approximation used for modeling such correlation is questioned here. Weaver's model was motivated by the fact that earlier models derived by Davy and Lyon assumed independent eigenfrequencies and led to an overestimation with respect to relative variances found in practice. It is shown here that this overestimation is due to an inadequate truncation of the modal expansion, and to an improper choice of the frequency range over which ensemble averages of the eigenfrequencies is defined. An alternative definition is proposed, settling the inconsistency; predicted relative variances are found to be in good agreement with experimental data. These results rehabilitate former approaches that were based on independence assumptions between eigenfrequencies. Some former studies showed that simpler correlation models could be used to predict the statistics of some field-related physical quantity at low modal overlap. The present work confirms that this is also the case when dealing with transmission functions.