bluuebunny/crossref_metadata_2025 huggingface dataset:
Cysteinoyl‐ and Cysteine‐containing Dipeptidoylbenzotriazoles with Free Sulfhydryl Groups: Easy Access to N‐terminal and Internal Cysteine Peptides
Authors: Ibrahim Tarek S. , Tala Srinivasa R. , El‐Feky Said A. , Abdel‐Samii Zakaria K. , Katritzky Alan R.
Published: December 2011

N‐Protected cysteines 4a–c each with a free sulfhydryl group were prepared in 70–75% yields by treatment of l‐cysteine with 1‐(benzyloxycarbonyl) benzotriazole (Cbz‐Bt) 1a, N‐(tert‐butyloxy‐carbonyl)benzotriazole (Boc‐Bt) 1b, and 1‐(9‐fluorenylmethoxy‐carbonyl)benzotriazole (Fmoc‐Bt) 1c, respectively. N‐Protected, free sulfhydryl cysteines 4a–c were then converted into the corresponding N‐protected, free sulfhydryl cysteinoylbenzotriazoles 7a–c (70–85%), which on treatment with diverse amino acids and dipeptides afforded the corresponding N‐protected, free sulfhydryl N‐terminal cysteine dipeptides 8a–e and tripeptides 8f–h in 73–80% yields. N‐Protected, free sulfhydryl cysteine‐containing dipeptides 9a,b were converted into the corresponding N‐protected, free sulfhydryl dipeptidoylbenzotriazoles 10a,b (69–81%), which on treatment with amino acids, dipeptides, and a tripeptide afforded internal cysteine tripeptides 11a–c, tetrapeptides 11d,e and pentapeptide 11f, each containing a N‐protected, free sulfhydryl groups in 70–90% yields under mild conditions. Treatment of N‐protected, free sulfhydryl cysteinoylbenzotriazole 7a with diamines 12a,b afforded directly the cysteine‐containing disulfide‐bridged cyclic peptides 14a,b in 50% yields.
Correlates of Mental Health Among Latino Farmworkers in North Carolina
Authors: Crain Rebecca , Grzywacz Joseph G. , Schwantes Melody , Isom Scott , Quandt Sara A. , Arcury Thomas A.
Published: December 2011

Purpose: Latino farmworkers are a vulnerable population who confront multiple threats to their mental health. Informed by the stress‐process model of psychiatric disorder, the goal of this paper is to determine primary and context‐specific stressors of poor mental health among Latino farmworkers.

Methods: Structured interview data were obtained from farmworkers (N = 69) in 6 counties in eastern and western North Carolina.

Findings: Results indicated that a substantial number of farmworkers have poor mental health, as indicated by elevated depressive symptoms (52.2%) and anxiety (16.4%). Results also indicated that each mental health outcome had different predictors.

Conclusion: Addressing the mental health issues of farmworkers requires a comprehensive, multifaceted approach.
Gene flow among wild and domesticated almond species: insights from chloroplast and nuclear markers
Authors: Delplancke Malou , Alvarez Nadir , Espíndola Anahí , Joly Hélène , Benoit Laure , Brouck Elise , Arrigo Nils
Published: December 2011

Hybridization has played a central role in the evolutionary history of domesticated plants. Notably, several breeding programs relying on gene introgression from the wild compartment have been performed in fruit tree species within the genus Prunus but few studies investigated spontaneous gene flow among wild and domesticated Prunus species. Consequently, a comprehensive understanding of genetic relationships and levels of gene flow between domesticated and wild Prunus species is needed. Combining nuclear and chloroplastic microsatellites, we investigated the gene flow and hybridization among two key almond tree species, the cultivated Prunus dulcis and one of the most widespread wild relative Prunus orientalis in the Fertile Crescent. We detected high genetic diversity levels in both species along with substantial and symmetric gene flow between the domesticated P. dulcis and the wild P. orientalis. These results were discussed in light of the cultivated species diversity, by outlining the frequent spontaneous genetic contributions of wild species to the domesticated compartment. In addition, crop‐to‐wild gene flow suggests that ad hoc transgene containment strategies would be required if genetically modified cultivars were introduced in the northwestern Mediterranean.
Changing organisms in rapidly changing anthropogenic landscapes: the significance of the ‘Umwelt’‐concept and functional habitat for animal conservation
Authors: Van Dyck Hans
Published: December 2011

There is a growing recognition for the significance of evolutionary thinking in ecology and conservation biology. However, ecology and conservation studies often work with species‐specific, fixed traits that ignore intraspecific variation. The way the habitat of a species is considered is an example of typological thinking biased by human perception. Structural habitat units (e.g., land cover types) as perceived by humans may not represent functional habitat units for other organisms. Human activity may also interfere with the environmental information used by organisms. Therefore, the Umwelt‐concept from ethology needs to be integrated in the way we think about habitat and habitat selection. It states that different organisms live in different perceptual worlds dealing with specific subsamples of the environment as a result of their evolutionary and developmental history. The resource‐based habitat concept is a functional habitat model based on resource distributions (consumables and conditions) and individual movements. This behavioural approach takes into account aspects that relate to the perceptual world of organisms. This approach may offer new opportunities for conservation and may help avoid failures with habitat restoration. Perceptual ability may be subject to adaptive change, but it may also constrain organisms from showing adaptive behaviours in rapidly changing environments.
Impact of a single one‐to‐one education session on glycemic control in patients with diabetes
Authors: BANERJEE Moulinath , MACDOUGALL Michelle , LAKHDAR Abdul F.
Published: December 2011

Background:  Education is one of the pivotal aspects of diabetes care. The impact of education has been found to be efficacious in the short term, but tends to lose efficacy in the long term. The hypothesis tested here was that one‐to‐one education would confer knowledge that would be reflected in metabolic improvement in this group of participants with diabetes.

Methods:  Thirty‐nine patients with type 2 diabetes mellitus and poor diabetes control attended a one‐to‐one diabetic and dietetic education session with a diabetic specialist nurse and a diabetes specialist dieticican. Glycemic control was assessed by measuring serum glycosolated hemoglobin (HbA1c) measurements before the session and at 6 and 12 months afterwards.

Results:  The HbA1c levels fell significantly in the whole group to 8.0 ± 0.5% (P < 0.05) at 6 months and to 8.3 ± 0.7% (P < 0.05) at the final visit from a baseline of 9.2 ± 0.5%. Compared to female patients, male patients had a similar drop in HbA1c at 6 months of 1.1%, which persisted until the final visit, when the drop was –1.3% vs 0.3% (P < 0.05).

Conclusions:  A single episode of one‐to‐one diabetic and dietetic education to subjects with poor diabetic control is effective in improving short‐ and long‐term diabetic control for up to 1 year. Male patients were found to have a better response than female patients.
Role and therapeutic potential of PI3K‐mTOR signaling in de novo resistance to BRAF inhibition
Authors: Deng W. , Vashisht Gopal Y. N. , Scott A. , Chen G. , Woodman S. E. , Davies M. A.
Published: December 2011

BRAF inhibition is highly active in BRAF‐mutant melanoma, but the degree and duration of responses is quite variable. Improved understanding of the mechanisms of de novo resistance may lead to rational therapeutic strategies with improved efficacy. Proteomic analysis of BRAF‐mutant, PTEN‐wild‐type human melanoma cell lines treated with PLX4720 demonstrated that sensitive and de novo resistant lines exhibit similar RAS‐RAF‐MEK‐ERK pathway inhibition, but the resistant cells exhibited durable activation of S6 and P70S6K. Treatment with the mTOR inhibitor rapamycin blocked activation of P70S6K and S6, but it also increased activation of AKT and failed to induce cell death. Combined treatment with rapamycin and PX‐866, a PI3K inhibitor, blocked the activation of S6 and AKT and resulted in marked cell death when combined with PLX4720. The results support the rationale for combined targeting of BRAF and the PI3K‐AKT pathways and illustrate how target selection will be critical to such strategies.
The prevalence of cataract in a population with and without type 2 diabetes mellitus
Authors: Olafsdottir Eydis , Andersson Dan K. G. , Stefánsson Einar
Published: December 2011

Purpose:  To evaluate the prevalence and risk factors of lens opacities in a geographically defined population of subjects with type 2 diabetes mellitus compared with a control population.

Methods:  Subjects in the community of Laxå with a diagnosis of type 2 diabetes mellitus (n = 275) and a control group (n = 256) participated in the study. Lens opacities were graded with Lens Opacities Classification System II in all participants. Lens Opacities Classification System score ≥2 was considered as significant lens opacity. Anthropometric and blood chemistry data were collected for all participants in connection with the eye examination. For the diabetic population, yearly updated information on glucose control, blood pressure and body mass index was available through medical records from diabetes diagnosis until the time of the eye examination.

Results:  The prevalence of significant cortical, posterior subcapsular and nuclear cataract was 65.5%, 42.5% and 48.0%, respectively, in the type 2 diabetes population in Laxå. In logistic regression analyses, all types of lens opacities were strongly associated with age (p < 0.0001). Cortical lens opacity was also associated with a diagnosis of diabetes (p < 0.0001), posterior subcapsular lens opacity with HbA1c (p < 0.0001) and nuclear lens opacity with female gender and higher heart rate (both p = 0.0004). In the diabetic population, all types of cataract were likewise strongly associated with age (p < 0.0001), posterior subcapsular cataract with HbA1c (p = 0.0032), nuclear cataract with female gender (p = 0.0002) and higher heart rate (p = 0.0008).

Conclusions:  Our study shows that cortical cataract is associated with diabetes mellitus, not necessarily defined by glucose control, whereas posterior subcapsular cataract is associated with glucose levels. Nuclear cataract is not associated with diabetes mellitus, but is more frequent in women and is also associated with higher heart rate.
Modeling spatial and dynamic variation in growth, yield, and yield stability of the bioenergy cropsMiscanthus × giganteusandPanicum virgatumacross the conterminousUnitedStates
Authors: Miguez Fernando E. , Maughan Matthew , Bollero Germán A. , Long Stephen P.
Published: December 2011

C4perennial grasses are being considered as environmentally and economically sustainable high yielding bioenergy feedstocks. Temporal and spatial variation in yield across the conterminiousUnitedStates is uncertain due to the limited number of field trials. Here, we use a semi‐mechanistic dynamic crop growth and production model to explore the potential ofMiscanthus × giganteus(Greef et.Deu.) andPanicum virgatumL. across the conterminousUnitedStates. By running the model for 32 years (1979–2010), we were able to estimate dry biomass production and stability. The maximum rainfed simulated end‐of‐growth‐season harvestable biomass forM. × giganteuswas ca. 40 Mg ha−1and ca. 20 Mg ha−1forP. virgatum. In addition, regions of the southeasternUnitedStates were identified as promising due to their high potential production and stability and their relative advantage when compared with county‐level maize biomass production. Regional and temporal variation was most strongly influenced by precipitation and soil water holding capacity.Miscanthus × giganteuswas on average 2.2 times more productive thanP. virgatumfor locations where yields were ≥10 Mg ha−1. The predictive ability of the model forP. virgatumwas tested with 30 previously published studies covering the eastern half of theUnitedStates and resulted in an index of agreement of 0.71 and a mean bias of only −0.62 Mg ha−1showing that, on average, the model tended to only slightly overestimate productivity. This study provides with potential production and variability which can be used for regional assessment of the suitability of dedicated bioenergy crops.
Occurrence of clinical depression during combination therapy with pegylated interferon alpha or natural human interferon beta plus ribavirin
Authors: Nomura Hideyuki , Miyagi Yuugou , Tanimoto Hironori , Yamashita Nobuyuki , Oohashi Seiji , Nishiura Saburo
Published: December 2011

Aim:  The onset of depression symptoms during pegylated interferon α plus ribavirin (PEG‐IFN/RBV) combination therapy has led to treatment discontinuation in some cases. In the present study, we conducted a questionnaire survey during treatment to determine whether natural human interferon β plus ribavirin (IFNβ/RBV) therapy is associated with a lower incidence of depression symptom onset compared with PEG‐IFN/RBV therapy.

Methods:  Seventy‐seven patients with chronic hepatitis C received PEG‐IFN/RBV (PR) or IFNβ/RBV (FR) therapy. A questionnaire survey was administered at the start of treatment, and at 4 and 12 weeks, using the Beck Depression Inventory II (BDI‐II) and the Pittsburgh Sleep Quality Index (PSQI).

Results:  BDI‐II scores in the PR group increased at 4 and 12 weeks, but remained unchanged in the FR group. At 12 weeks, the mean BDI‐II score and incidence of abnormalities with a BDI‐II score of ≥14 were significantly lower in the FR group than in the PR group. BDI‐II scores during IFNβ/RBV therapy in 11 patients currently using antidepressants remained unchanged up to 12 weeks. None of these 11 patients required addition or dose increases of antidepressants, and there was no evidence of worsened depression symptoms. Nine PR patients had BDI‐II scores of ≥14 and PSQI scores of ≥11 at 12 weeks.

Conclusions:  IFNβ/RBV therapy was associated with a lower incidence of depression symptom onset during treatment. In patients already diagnosed with depression, there was no evidence that IFNβ/RBV therapy caused any worsening of symptoms, indicating that IFNβ/RBV therapy is safe for patients with depression.
New Challenges for Product Design: The Product of Design
Authors: Grinyer Clive
Published: December 2011

Product design is still a craft, but product designers are now also in the business of interpreting cultural behavior and translating emotional requirements.
Histone deacetylase inhibitors as suppressors of bone destruction in inflammatory diseases
Authors: Cantley Melissa D , Bartold Peter M , Fairlie David P , Rainsford K D , Haynes David R
Published: December 2011

Objectives

Despite progress in developing many new anti-inflammatory treatments in the last decade, there has been little progress in finding treatments for bone loss associated with inflammatory diseases, such as rheumatoid arthritis and periodontitis. For instance, treatment of rheumatic diseases with anti-tumour necrosis factor-alpha agents has been largely successful in reducing inflammation, but there have been varying reports regarding its effectiveness at inhibiting bone loss. In addition, there is often a delay in finding the appropriate anti-inflammatory therapy for individual patients, and some therapies, such as disease modifying drugs, take time to have an effect. In order to protect the bone, adjunct therapies targeting bone resorption are being developed. This review focuses on new treatments based on using histone deacetylase inhibitors (HDACi) to suppress bone loss in these chronic inflammatory diseases.

Key findings

A number of selected HDACi have been shown to suppress bone resorption by osteoclasts in vitro and in animal models of chronic inflammatory diseases. Recent reports indicate that these small molecules, which can be administered orally, could protect the bone and might be used in combination with current anti-inflammatory treatments.

HDACi do have potential to suppress bone destruction in chronic inflammatory diseases including periodontitis and rheumatoid arthritis.
Liposomal topotecan formulation with a low polyethylene glycol grafting density: pharmacokinetics and antitumour activity
Authors: Li Chunlei , Wang Caixia , Yang Hanyu , Zhao Xi , Wei Na , Cui Jingxia
Published: December 2011

Objectives

PEGylated liposomes could evade recognition by the reticulo-endothelial system and prolong the circulation time of vesicles, resulting in enhanced targeting efficiency and antitumour effect. Typically, vesicles are modified with distearoylphosphatidylethanolamine (DSPE)-polyethylene glycol (PEG) at a high PEG grafting density. However, long circulation time and slow drug release rate might induce severe hand-foot syndrome in clinical practice. In this study, a liposomal topotecan formulation with a low PEG grafting density was prepared and its pharmacokinetics, acute toxicity and antitumour effect were investigated.

Methods

Topotecan was loaded into liposomes using an ammonium sulfate gradient. The resulting formulation was injected to healthy Wistar rats at different dose levels to investigate whether its clearance followed linear kinetics. Biodistribution was performed in Lewis lung cancer-bearing mice. The acute toxicity was evaluated in healthy mice and beagle dogs. To compare the antitumour effects of different formulations and dose schedule, RM-1 prostate, Lewis lung, H446 and L1210 cancer models were used.

Key findings

Topotecan could be encapsulated into low DSPE-PEG liposomes with ∼100% loading efficiency. The clearance of the liposomal formulation followed linear kinetics at a dose level ranging from 0.5 to 4 mg/kg despite the fact that the vesicles were coated at a low PEG density. Compared with free topotecan the liposomal formulation preferentially accumulated into tumour zones instead of normal tissues. Both formulations could rapidly accumulate into liver and tumour, but the liposomal formulation was cleared from tissues at a slow rate relative to the conventional formulation. In rats and beagle dogs, liposomal formulations could not induce skin toxicity. In all the tumour models, smaller split doses were more therapeutically active than larger doses when the overall dose intensity was equivalent.

Conclusions

This has been the first report that plasma kinetics of a liposomal formulation with a low PEG density followed linear kinetics. Moreover, due to its short circulation half-life, the formulation did not induce skin toxicity. Our data revealed that the dose schedule of liposomal drugs should be adjusted in accordance with the biophysical and biological properties of the formulations to achieve the optimal therapeutic efficacy.
Effects of diarylpentanoid analogues of curcumin on chemiluminescence and chemotactic activities of phagocytes
Authors: Jantan Ibrahim , Bukhari Syed Nasir Abbas , Lajis Nordin Haji , Abas Faridah , Wai Lam Kok , Jasamai Malina
Published: December 2011

Objectives

A series of 43 curcumin diarylpentanoid analogues were synthesized and evaluated for their inhibitory effects on the chemiluminescence and chemotactic activity of phagocytes in vitro.

Methods

The effects of the compounds on the respiratory burst of human whole blood and isolated human polymorphonuclear leukocytes (PMNs) were evaluated using a luminol-based chemiluminescence assay and their effect on chemotactic migration of PMNs was investigated using the Boyden chamber technique.

Key findings

Compounds 6, 17, 25 and 30 exhibited significant inhibitory activity on the oxidative burst of PMNs. The presence of methoxy groups at positions 2 and 5, and methoxylation and fluorination at positions 4 and 2 of both phenyl rings, respectively, may contribute significantly to their reactive oxygen species inhibition activity. Compounds 7, 17, 18, 24 and 32 showed strong inhibition of the chemotaxis migration of PMNs. Chlorination at various positions of both phenyl rings of cyclohexanone diarylpentanoid resulted in compounds with potent inhibitory effects on PMN migration.

Conclusions

The results suggest that some of these diarylpentanoid analogues are able to modulate the innate immune response of phagocytes at different steps, emphasizing their potential as a source of new immunomodulatory agents.
Comparative Validation Study on Identification of Premixed Flame Transfer Function
Authors: Tay-Wo-Chong Luis , Bomberg Sebastian , Ulhaq Ahtsham , Komarek Thomas , Polifke Wolfgang
Published: December 2011

The flame transfer function (FTF) of a premixed swirl burner was identified from a time series generated with computational fluid dynamics simulations of compressible, turbulent, reacting flow at nonadiabatic conditions. Results were validated against experimental data. For large eddy simulation (LES), the dynamically thickened flame combustion model with one step kinetics was used. For unsteady simulation in a Reynolds-averaged Navier–Stokes framework (URANS), the Turbulent Flame Closure model was employed. The FTF identified from LES shows quantitative agreement with experiment for amplitude and phase, especially for frequencies below 200 Hz. At higher frequencies, the gain of the FTF is underpredicted. URANS results show good qualitative agreement, capturing the main features of the flame response. However, the maximum amplitude and the phase lag of the FTF are underpredicted. Using a low-order network model of the test rig, the impact of the discrepancies in predicted FTFs on frequencies and growth rates of the lowest order eigenmodes were assessed. Small differences in predicted FTFs were found to have a significant impact on stability limits. Stability behavior in agreement with experimental data was achieved only with the LES-based flame transfer function.
Energy Usage in Natural Gas Pipeline Applications
Authors: Garcia-Hernandez Augusto , Brun Klaus
Published: December 2011

Energy required to transport the fluid is an important parameter to be analyzed and minimized in pipeline applications. However, the pipeline system requirements and equipment could impose different constraints for operating pipelines in the best manner possible. One of the critical parameters that it is looked at closely, is the machines’ efficiency to avoid unfavorable operating conditions and to save energy costs. However, a compression-transport system includes more than one machine and more than one station working together at different conditions. Therefore, a detailed analysis of the entire compression system should be conducted to obtain a real power usage optimization. This paper presents a case study that is focused on analyzing natural gas transport system flow maximization while optimizing the usage of the available compression power. Various operating scenarios and machine spare philosophies are considered to identify the most suitable conditions for an optimum operation of the entire system. Modeling of pipeline networks has increased in the past decade due to the use of powerful computational tools that provide good quality representation of the real pipeline conditions. Therefore, a computational pipeline model was developed and used to simulate the gas transmission system. All the compressors’ performance maps and their driver data such as heat rate curves for the fuel consumption, site data, and running speed correction curves for the power were loaded in the model for each machine. The pipeline system covers 218 miles of hilly terrain with two looped pipelines of 38″ and 36″ in diameter. The entire system includes three compressor stations along its path with different configurations and equipment. For the optimization, various factors such as good efficiency over a wide range of operating conditions, maximum flexibility of configuration, fuel consumption and high power available were analyzed. The flow rate was maximized by using instantaneous maximum compression capacity at each station while maintaining fixed boundary conditions. This paper presents typical parameters that affect the energy usage in natural gas pipeline applications and discusses a case study that covers an entire pipeline. A modeling approach and basic considerations are presented as well as the results obtained for the optimization.
Vocal characteristics of pygmy blue whales and their change over time
Authors: Gavrilov Alexander N. , McCauley Robert D. , Salgado-Kent Chandra , Tripovich Joy , Burton Chris
Published: December 2011

Vocal characteristics of pygmy blue whales of the eastern Indian Ocean population were analyzed using data from a hydroacoustic station deployed off Cape Leeuwin in Western Australia as part of the Comprehensive Nuclear-Test-Ban Treaty monitoring network, from two acoustic observatories of the Australian Integrated Marine Observing System, and from individual sea noise loggers deployed in the Perth Canyon. These data have been collected from 2002 to 2010, inclusively. It is shown that the themes of pygmy blue whale songs consist of ether three or two repeating tonal sounds with harmonics. The most intense sound of the tonal theme was estimated to correspond to a source level of 179 ± 2 dB re 1 μPa at 1 m measured for 120 calls from seven different animals. Short-duration calls of impulsive downswept sound from pygmy blue whales were weaker with the source level estimated to vary between 168 to 176 dB. A gradual decrease in the call frequency with a mean rate estimated to be 0.35 ± 0.3 Hz/year was observed over nine years in the frequency of the third harmonic of tonal sound 2 in the whale song theme, which corresponds to a negative trend of about 0.12 Hz/year in the call fundamental frequency.
Multi-carrier synthetic aperture communication in shallow water: Experimental results
Authors: Kang Taehyuk , Song H. C. , Hodgkiss W. S.
Published: December 2011

Orthogonal frequency division multiplexing (OFDM) communications in the presence of motion is investigated using data collected from the Kauai Acomms MURI 2008 (KAM08) experiment, conducted off the western side of Kauai, Hawaii, in June–July 2008. The experiment involved a vertical array moored in 106 m deep shallow water and a source towed at a speed of 3 knots at ranges between 600 m and 6 km. In order to attain reliable communications with only a single receive element, a synthetic aperture approach is applied. After combining multiple transmissions, an error-free reception is achieved with a low-density parity-check code, confirming the feasibility of coherent synthetic aperture communications using OFDM.
Improved prediction of the turbulence-shear contribution to wind noise pressure spectra
Authors: Yu Jiao , Raspet Richard , Webster Jeremy , Abbott JohnPaul
Published: December 2011

In previous research [Raspet et al., J. Acoust. Soc. Am. 123(3), 1260–1269 (2008)], predictions of the low frequency turbulence-turbulence and turbulence-mean shear interaction pressure spectra measured by a large wind screen were developed and compared to the spectra measured using large spherical wind screens in the flow. The predictions and measurements agreed well except at very low frequencies where the turbulence-mean shear contribution dominated the turbulence-turbulence interaction pressure. In this region the predicted turbulence-mean shear interaction pressure did not show consistent agreement with microphone measurements. The predicted levels were often much larger than the measured results. This paper applies methods developed to predict the turbulence-shear interaction pressure measured at the ground [Yu et al., J. Acoust. Soc. Am. 129(2), 622–632 (2011)] to improve the prediction of the turbulence-shear interaction pressure above the ground surface by incorporating a realistic wind velocity profile and realistic turbulence anisotropy. The revised prediction of the turbulence-shear interaction pressure spectra compares favorably with wind-screen microphone measurements in large wind screens at low frequency.
Design and evaluation of an aeroacoustic wind tunnel for measurement of axial flow fans
Authors: Bilka M. , Anthoine J. , Schram C.
Published: December 2011

An anechoic wind tunnel dedicated to fan self-noise studies has been designed and constructed at the von Karman Institute The multi-chamber, mass flow driven design allows for all fan performance characteristics, aerodynamic quantities (e.g., wake turbulence measurements), and acoustic properties to be assessed in the same facility with the same conditions. The acoustic chamber performance is assessed using the optimum reference method and found to be within the ISO 3745 standards down to 150 Hz for pure tone and broadband source mechanisms. The additional influence of installation effects of an aerodynamic inlet was found to create a scattered sound field only near the source location, while still providing good anechoic results at more distant sound pressure measurement positions. It was found to have inflow properties, span-wise uniformity, and low turbulence intensity, consistent with those desired for fan self-noise studies.
Impact of attenuation on guided mode wavenumber measurement in axial transmission on bone mimicking plates
Authors: Minonzio Jean-Gabriel , Foiret Josquin , Talmant Maryline , Laugier Pascal
Published: December 2011

Robust signal processing methods adapted to clinical measurements of guided modes are required to assess bone properties such as cortical thickness and porosity. Recently, an approach based on the singular value decomposition (SVD) of multidimensional signals recorded with an axial transmission array of emitters and receivers has been proposed for materials with negligible absorption, see Minonzio et al. [J. Acoust. Soc. Am. 127, 2913–2919 (2010)]. In presence of absorption, the ability to extract guided mode degrades. The objective of the present study is to extend the method to the case of absorbing media, considering attenuated plane waves (complex wavenumber). The guided mode wavenumber extraction is enhanced and the order of magnitude of the attenuation of the guided mode is estimated. Experiments have been carried out on 2 mm thick plates in the 0.2–2 MHz bandwidth. Two materials are inspected: polymethylacrylate (PMMA) (isotropic with absorption) and artificial composite bones (Sawbones, Pacific Research Laboratory Inc, Vashon, WA) which is a transverse isotropic absorbing medium. Bulk wave velocities and bulk attenuation have been evaluated from transmission measurements. These values were used to compute theoretical Lamb mode wavenumbers which are consistent with the experimental ones obtained with the SVD-based approach.
Subjective ratings of whole-body vibration for single- and multi-axis motion
Authors: Mansfield Neil J. , Maeda Setsuo
Published: December 2011

Real-world whole-body vibration exposures comprise motion in fore–aft, lateral, and vertical directions simultaneously. There can also be components of roll, pitch, and yaw. If evaluating vibration with respect to human response, most investigators will use methods defined in ISO 2631-1. This uses frequency weightings that were originally derived from laboratory studies of the subjective responses to vibration in one direction at a time. This paper describes experiments that were carried out using a 6 degree-of-freedom vibration simulator to validate the applicability of ISO 2631-1 in multi-axis environments. Fifteen subjects were exposed to 87 stimuli comprising single-axis, dual-axis, and tri-axial random vibration, to which they were required to produce subjective ratings. It is shown that in this study the root-sum-of-squares method of summation of subjective ratings in individual axes was an adequate technique for prediction of subjective rating of multi-axis vibration. Better agreement between objective and subjective measures of vibration was obtained for unweighted vibration than for frequency weighted signals. The best agreement for this study was achieved when axis multiplying factors were set at 2.2 and 2.4 for x- and y-axis vibration, respectively. Different values could be appropriate for other postures, seats, and vibration conditions and should be determined in future studies.
Inverse solution of ear-canal area function from reflectance
Authors: Rasetshwane Daniel M. , Neely Stephen T.
Published: December 2011

A number of acoustical applications require the transformation of acoustical quantities, such as impedance and pressure that are measured at the entrance of the ear canal, to quantities at the eardrum. This transformation often requires knowledge of the shape of the ear canal. Previous attempts to measure ear-canal area functions were either invasive, non-reproducible, or could only measure the area function up to a point mid-way along the canal. A method to determine the area function of the ear canal from measurements of acoustic impedance at the entrance of the ear canal is described. The method is based on a solution to the inverse problem in which measurements of impedance are used to calculate reflectance, which is then used to determine the area function of the canal. The mean ear-canal area function determined using this method is similar to mean ear-canal area functions measured by other researchers using different techniques. The advantage of the proposed method over previous methods is that it is non- invasive, fast, and reproducible.
Incorporating source directionality into outdoor sound propagation calculations
Authors: Vecherin Sergey N. , Keith Wilson D. , Ostashev Vladimir E.
Published: December 2011

Many outdoor sound sources, such as aircraft or ground vehicles, exhibit directional radiation patterns. However, long-range sound propagation algorithms are usually formulated for omnidirectional point sources. This paper describes two methods for incorporating directional sources into long-range sound propagation algorithms. The first is the equivalent source method (ESM), which determines a compact distribution of omnidirectional point sources reproducing a given directivity pattern in the far field. This method can be used with any propagation algorithm because it explicitly reconstructs a source function as a set of point sources with certain amplitudes and positions. The second is a directional starter method (DSM), which is developed specifically for the parabolic equation (PE) algorithms. This method derives narrow- or wide-angle directional starter fields, corresponding to a given source directivity pattern, without reconstructing the equivalent source distribution. Although the ESM can also be used for the PE, the DSM is simpler and can be more convenient, especially if the sound propagation is calculated only for one or a few azimuthal directions. While these two methods are found to produce generally distinct starter fields, they nonetheless yield identical directivity patterns.
Estimating material viscoelastic properties based on surface wave measurements: A comparison of techniques and modeling assumptions
Authors: Royston Thomas J. , Dai Zoujun , Chaunsali Rajesh , Liu Yifei , Peng Ying , Magin Richard L.
Published: December 2011

Previous studies of the first author and others have focused on low audible frequency (<1 kHz) shear and surface wave motion in and on a viscoelastic material comprised of or representative of soft biological tissue. A specific case considered has been surface (Rayleigh) wave motion caused by a circular disk located on the surface and oscillating normal to it. Different approaches to identifying the type and coefficients of a viscoelastic model of the material based on these measurements have been proposed. One approach has been to optimize coefficients in an assumed viscoelastic model type to match measurements of the frequency-dependent Rayleigh wave speed. Another approach has been to optimize coefficients in an assumed viscoelastic model type to match the complex-valued frequency response function (FRF) between the excitation location and points at known radial distances from it. In the present article, the relative merits of these approaches are explored theoretically, computationally, and experimentally. It is concluded that matching the complex-valued FRF may provide a better estimate of the viscoelastic model type and parameter values; though, as the studies herein show, there are inherent limitations to identifying viscoelastic properties based on surface wave measurements.
A threatened beluga (Delphinapterus leucas) population in the traffic lane: Vessel-generated noise characteristics of the Saguenay-St. Lawrence Marine Park, Canada
Authors: McQuinn Ian H. , Lesage Véronique , Carrier Dominic , Larrivée Geneviève , Samson Yves , Chartrand Sylvain , Michaud Robert , Theriault James
Published: December 2011

The threatened resident beluga population of the St. Lawrence Estuary shares the Saguenay-St. Lawrence Marine Park with significant anthropogenic noise sources, including marine commercial traffic and a well-established, vessel-based whale-watching industry. Frequency-dependent (FD) weighting was used to approximate beluga hearing sensitivity to determine how noise exposure varied in time and space at six sites of high beluga summer residency. The relative contribution of each source to acoustic habitat degradation was estimated by measuring noise levels throughout the summer and noise signatures of typical vessel classes with respect to traffic volume and sound propagation characteristics. Rigid-hulled inflatable boats were the dominant noise source with respect to estimated beluga hearing sensitivity in the studied habitats due to their high occurrence and proximity, high correlation with site-specific FD-weighted sound levels, and the dominance of mid-frequencies (0.3–23 kHz) in their noise signatures. Median C-weighted sound pressure level (SPLRMS) had a range of 19 dB re 1 μPa between the noisiest and quietest sites. Broadband SPLRMS exceeded 120 dB re 1 μPa 8–32% of the time depending on the site. Impacts of these noise levels on St. Lawrence beluga will depend on exposure recurrence and individual responsiveness.
Audibility-based predictions of speech recognition for children and adults with normal hearing
Authors: McCreery Ryan W. , Stelmachowicz Patricia G.
Published: December 2011

This study investigated the relationship between audibility and predictions of speech recognition for children and adults with normal hearing. The Speech Intelligibility Index (SII) is used to quantify the audibility of speech signals and can be applied to transfer functions to predict speech recognition scores. Although the SII is used clinically with children, relatively few studies have evaluated SII predictions of children’s speech recognition directly. Children have required more audibility than adults to reach maximum levels of speech understanding in previous studies. Furthermore, children may require greater bandwidth than adults for optimal speech understanding, which could influence frequency-importance functions used to calculate the SII. Speech recognition was measured for 116 children and 19 adults with normal hearing. Stimulus bandwidth and background noise level were varied systematically in order to evaluate speech recognition as predicted by the SII and derive frequency-importance functions for children and adults. Results suggested that children required greater audibility to reach the same level of speech understanding as adults. However, differences in performance between adults and children did not vary across frequency bands.
Restraining mechanisms in regulating glottal closure during phonation
Authors: Zhang Zhaoyan
Published: December 2011

Recent experimental studies showed that isotropic vocal fold models were often blown wide apart and thus not able to maintain adductory position, resulting in voice production with noticeable breathy quality. This study showed that the capability of the vocal fold to resist deformation against airflow and maintain adductory position can be improved by stiffening the body-layer stiffness or increasing the anterior-posterior tension of the vocal folds, which presumably can be achieved through the contraction of the thyroarytenoid (TA) and cricothyroid (CT) muscles, respectively. Experiments in both physical models and excised larynges showed that, when these restraining mechanisms were activated, the vocal folds were better able to maintain effective adduction, resulting in voice production with much clearer quality and reduced breathiness. In humans, one or more restraining mechanisms may be activated at different levels to accommodate the varying degree of restraining required under different voice conditions.
The Emerging Role of Linear Ubiquitination in Cell Signaling
Authors: Emmerich Christoph H. , Schmukle Anna C. , Walczak Henning
Published: December 2011

Linear ubiquitin chains transmit signals that are induced by diverse stimuli and regulate cell activation and death.
Science Signaling
Podcast: 20 December 2011
Authors: Krammer Peter H. , VanHook Annalisa M.
Published: December 2011

Suppression of conventional T cells by regulatory T cells requires inhibition of calcium signaling downstream of the T cell receptor.
6-Alkynylpurines bearing electronacceptor substituents: Preparation, reactivity in cycloaddition reactions and cytostatic activity
Authors: Křováček Martin , Dvořáková Hana , Votruba Ivan , Císařová Ivana , Dvořák Dalimil
Published: December 2011

While direct Sonogashira coupling of 6-halopurines with methyl propiolate and with propargyl aldehyde was not successful, the corresponding orthoester and propargyl aldehyde diethylacetal reacted smoothly. Such prepared orthoester was then converted to the desired methylester by methanolysis, the acetal was too stable to be hydrolyzed. The obtained 6-ethynylpurines, bearing orthoester, acetal, methoxycarbonyl and for comparison also the phenyl substituent on the ethynyl group, were subjected to the cycloaddition reaction with cyclopentadiene, diazomethane and phenylazide. Electron deficient alkynylpurines were considerably more reactive in this reaction compared to the not activated phenylethynyl derivative. The prepared alkynylpurines exhibited medium cytostatic activity (IC50 = 2.6–15 μM), while the cycloadducts were inactive.
Human papillomavirus detection in dysplastic and malignant oral verrucous lesions
Authors: Stokes Angela , Guerra Eliete , Bible Jon , Halligan Eugene , Orchard Guy , Odell Edward , Thavaraj Selvam
Published: December 2011

The role of human papillomaviruses (HPV) in dysplastic and malignant oral verrucous lesions is controversial since there is a wide range in the incidence of virus detection. This study used a multi-tiered method of HPV detection using DNA in-situ hybridisation (ISH) for low- and high-risk subtypes, consensus PCR, and HPV genotype analysis in archival tissue from 20 cases of dysplastic and malignant oral verrucous lesions. The biological significance of HPV DNA detection was assessed by p16 immunohistochemistry (IHC). While 1/7 carcinomas and 5/13 dysplasias contained HPV DNA by consensus PCR and genotype analysis, all specimens were negative for low- and high-risk HPV ISH and negative for p16 IHC. Results show that although high-risk HPV DNA is detectable in a subset of these lesions, the lack of p16 overexpression suggests that the oncogenic process is not driven by HPV oncoproteins.
Increased probability of repetitive spinal motoneuron activation by transcranial magnetic stimulation after muscle fatigue in healthy subjects
Authors: Andersen Birgit , Felding Ulrik Ascanius , Krarup Christian
Published: December 2011

Triple stimulation technique (TST) has previously shown that transcranial magnetic stimulation (TMS) fails to activate a proportion of spinal motoneurons (MNs) during motor fatigue. The depression in size of the TST response, but no attenuation of the conventional motor-evoked potential, suggested increased probability of repetitive spinal MN activation during exercise, even if some MNs failed to discharge by the brain stimulus. Here we used a modified TST [quadruple stimulation (QuadS) and quintuple stimulation (QuintS)] to examine the influence of fatiguing exercise on second and third MN discharges after a single TMS in healthy subjects. This method allows an estimation of the percentage of double and triple discharging MNs. Following a sustained contraction of the abductor digiti minimi muscle at 50% maximal force maintained to exhaustion, the size of QuadS and QuintS responses increased markedly, reflecting that a greater proportion of spinal MNs was activated two or three times by the transcranial stimulus. The size of QuadS responses did not return to precontraction levels during 10-min observation time, indicating long-lasting increase in excitatory input to spinal MNs. In addition, the postexercise behavior of QuadS responses was related to the duration of the contraction, pointing to a correlation between repeated activation of MNs and the subject's ability to maintain force. In conclusion, the study confirmed that an increased fraction of spinal MNs fire more than once in response to TMS when the muscle is fatigued. Repetitive MN firing may provide an adaptive mechanism to maintain motor unit activation and task performance during sustained voluntary activity.
The effect of higher ATP cost of contraction on the metabolic response to graded exercise in patients with chronic obstructive pulmonary disease
Authors: Layec Gwenael , Haseler Luke J. , Richardson Russell S.
Published: December 2011

To better understand the metabolic implications of a higher ATP cost of contraction in chronic obstructive pulmonary disease (COPD), we used31P-magnetic resonance spectroscopy (31P-MRS) to examine muscle energetics and pH in response to graded exercise. Specifically, in six patients and six well-matched healthy controls, we determined the intracellular threshold for pH (TpH) and inorganic phosphate-to-phosphocreatine ratio (TPi/PCr) during progressive dynamic plantar flexion exercise with work rate expressed as both absolute and relative intensity. Patients with COPD displayed a lower peak power output (WRmax) compared with controls (controls 25 ± 4 W, COPD 15 ± 5 W, P = 0.01) while end-exercise pH (controls 6.79 ± 0.15, COPD 6.76 ± 0.21, P = 0.87) and PCr consumption (controls 82 ± 10%, COPD 70 ± 18%, P = 0.26) were similar between groups. Both TpHand TPi/PCroccurred at a significantly lower absolute work rate in patients with COPD compared with controls (controls: 14.7 ± 2.4 W for TpHand 15.3 ± 2.4 W for TPi/PCr; COPD: 9.7 ± 4.5 W for TpHand 10.0 ± 4.6 W for TPi/PCr, P < 0.05), but these thresholds occurred at the same percentage of WRmax (controls: 63 ± 11% WRmax for TpHand 67 ± 18% WRmax for TPi/PCr; COPD: 59 ± 9% WRmax for TpHand 61 ± 12% WRmax for TPi/PCr, P > 0.05). Indexes of mitochondrial function, the PCr recovery time constant (controls 42 ± 7 s, COPD 45 ± 11 s, P = 0.66) and the PCr resynthesis rate (controls 105 ± 21%/min, COPD 91 ± 31%/min, P = 0.43) were similar between groups. In combination, these results reveal that when energy demand is normalized to WRmax, as a consequence of higher ATP cost of contraction, patients with COPD display the same metabolic pattern as healthy subjects, suggesting that skeletal muscle energy production is well preserved in these patients.