bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of 0.1% Ammonium Hydroxide to Replace Sodium Tripolyphosphate in Fresh Meat Injection Brines
Authors: Cerruto‐Noya C.A. , VanOverbeke D.L. , DeWitt C.A. Mireles
Published: July 2009

ABSTRACT:  Paired USDA Select beef strip loins (n = 10), aged 2 d, were injected with either an alkaline‐based (3.6% sodium chloride, 1% Herbalox seasoning, adjusted to pH 10 with ammonium hydroxide [approximately 0.1%, FFC grade]) or a phosphate‐based (3.6% sodium chloride, 1% Herbalox seasoning, 4.5% sodium tripolyphosphate) brine. Steaks were evaluated for 19 d. Overall, phosphate‐injected steaks performed better than alkaline‐injected steaks with respect to cook yield, water holding capacity, lipid oxidation, color stability, tenderness, and juiciness. Phosphate‐injected steaks also had less purge than alkaline‐injected steaks, as confirmed by composition analysis. Phosphate‐injected steaks were higher in moisture and ash content, and were nearly 2% lower in protein content. Alkaline‐injected steaks had significantly lower aerobic (approximately 1 log lower) and anaerobic (approximately 2 log lower) plate counts. Final meat pH probably contributed to the differences observed between treatments. The final pH of phosphate‐injected steak was 5.99 while that of alkaline‐injected steak was 5.73. Further research should be conducted to determine the concentration of ammonium hydroxide needed in the alkaline‐based brine to increase the final meat pH to similar levels found in the phosphate‐injected steaks.
Screening for Beneficial Effects of Oral Intake of Sweet Corn by DNA Microarray Analysis
Authors: Tokuji Yoshihiko , Akiyama Kyoko , Yunoki Keita , Kinoshita Mikio , Sasaki Keiko , Kobayashi Hitoshi , Wada Masahiro , Ohnishi Masao
Published: July 2009

ABSTRACT:  To identify novel functions of the oral intake of sweet corn, we performed DNA microarray analysis of the livers of sweet corn‐fed mice. Functional annotation clustering 1600 genes with expression levels that were affected (more than 1.5‐fold change) by dietary sweet corn indicated that both cell proliferation and programmed cell death were modulated by sweet corn intake. In the Wnt signaling pathway, which is involved in cell proliferation, the levels of Jun and β‐catenin expression were downregulated by dietary sweet corn. The mRNA levels of Rb and p53, negative regulators of the cell cycle, were increased in mice fed with sweet corn. Dietary corn upregulated expression levels of genes that regulate apoptosis positively (for example, BOK, BID, CASP4). These results suggested that sweet corn is a valuable food for suppressing cancer. Oral administration of sweet corn inhibited tumor growth (36.6% reduce in tumor weight, P < 0.05) in mice inoculated with Ehrlich tumor cells.
Factors Affecting Migration of Vanillin from Chitosan/Methyl Cellulose Films
Authors: Sangsuwan J. , Rattanapanone N. , Auras R.A. , Harte B.R. , Rachtanapun P.
Published: July 2009

ABSTRACT:  The diffusion kinetics and factors affecting the migration of vanillin from chitosan/methyl cellulose (Chi/MC) films into water, cantaloupe juice (CJ), pineapple juice (PJ), and citrate buffer adjusted to pH values of 3.5, 5, and 6.5 were studied. Vanillin was incorporated into the Chi/MC films to provide an inhibitory effect against microorganisms. Initial vanillin concentration in the films, temperature, and pH of extracting solvent impacted the migration behavior of vanillin. The diffusion coefficients (D) followed the Arrhenius equation and increased as temperature increased for all the solvents. As temperature rose, the rate increment of the diffusion of vanillin into pineapple juice was higher than that into water and cantaloupe juice. Films containing lower vanillin content had a higher diffusion coefficient than those containing high vanillin content. Migration of vanillin was affected by pH rather than acid concentration. Lower pH resulted in a higher migration rate.
DNA Damage, Repair and Photoadaptation in a Xiphophorus Fish Hybrid
Authors: Mitchell David L. , Paniker Lakshmi , Douki Thierry
Published: July 2009

Exposure to sunlight is responsible for most cutaneous malignant melanomas in the human population. It is very likely that DNA damage is an initial event in melanomagenesis, however, the role played by this damage is an open question. To this end, we used a hemipigmented F1 hybrid of the fish genus Xiphophorus and HPLC tandem mass spectrometry to examine the effects of melanin on the induction and repair of the predominant UV‐induced photoproducts formed in skin cell DNA. We found that heavily pigmented skin cells had about half the damage of nonpigmented cells and the relative induction of the major photoproducts was independent of the degree of pigmentation. The efficiency of photoenzymatic repair was the same in nonpigmented and pigmented areas of the fish. We found no evidence of residual damage at 10 days after the last exposure. Most striking was that repeated exposure to multiple doses of UVB caused a very significant photoadaptive response. Rather than an accumulation of damage after five doses of UVB we saw a significant reduction in the amount of damage induced after the final dose compared with the initial dose. The relevance of these observations is discussed in the context of melanoma susceptibility and UVB thresholds.
MC1R Gene Polymorphism Affects Skin Color and Phenotypic Features Related to Sun Sensitivity in a Population of French Adult Women
Authors: Latreille Julie , Ezzedine Khaled , Elfakir Anissa , Ambroisine Laurence , Gardinier Sophie , Galan Pilar , Hercberg Serge , Gruber Florian , Rees Jonathan , Tschachler Erwin , Guinot Christiane
Published: July 2009

The melanocortin‐1 receptor (MC1R) gene is known to play a major role in skin and hair pigmentation and to be highly polymorphic in Caucasians. This study was performed to investigate the relationships between MC1R gene polymorphisms and skin color in a large sample of French middle‐aged Caucasian women. The codons 60 to 265 and the codon 294 of the MC1R gene were sequenced in 488 women. The skin color was measured on the inner side of the forearm using a spectrophotometric instrument. Fifteen variants were identified: Arg151Cys, Arg160Trp, Arg142His, Asp294His, Ile155Thr, Asp84Glu, Val60Leu, Val92Met, Arg163Gln, Ser83Pro, Thr95Met, Pro256Ser, Val265Ile, Ala166Ala and Gln233Gln. Women carrying Arg151Cys, Asp294His, Arg160Trp and Asp84Glu variants had a significantly higher reflectance in the red region, which indicates a lower level of functional melanin. This association was the most pronounced for women carrying Asp84Glu. In contrast, no significant difference was observed for other variants. Moreover, associations between MC1R polymorphisms and the risks of experiencing sunburn and of having freckles were found independently of skin color. Our findings support the hypothesis that MC1R polymorphisms do not necessarily alter the skin color but should sensitize the skin to UV‐induced DNA damage.
Mitigating Photosensitivity of Erythropoietic Protoporphyria Patients by an Agonistic Analog of α‐Melanocyte Stimulating Hormone†
Authors: Harms Juergen H. , Lautenschlager Stephan , Minder Christoph E. , Minder Elisabeth I.
Published: July 2009

Erythropoietic protoporphyria (EPP) is a rare hereditary disorder characterized by dermal accumulation of the photosensitizer protoporphyrin IX. Following sunlight exposure, the resulting photosensitivity is manifested first as pain, later as erythema, edema and dermal lesions. Afamelanotide (Nle4‐d‐Phe7‐α‐MSH), a synthetic analog of α‐melanocyte stimulating hormone and agonist of the melanocortin‐1‐receptor, promotes melanin synthesis, increasing skin pigmentation. This study examines the efficacy of afamelanotide in preventing symptoms in patients with EPP. A sustained‐release subcutaneous implant of 20 mg afamelanotide was administered twice, with a 60‐day interval to five EPP patients. Therapeutic efficacy was assessed by a photoprovocation test using standardized white light irradiation, melanin density (MD) determination and daily recording of sunlight exposure and symptoms. From Day 30 to Day 120 tolerance to photoprovocation significantly increased compared with baseline (P = 0.007) and skin MD was significantly higher than that recorded at baseline (P = 0.004). Except for two low‐grade pain episodes, patients recorded no phototoxic events past Day 4 of treatment. Tolerance to natural sunlight was up to 24 times longer than prior to therapy. The findings demonstrate beneficial effects of afamelanotide in patients with EPP. Due to the limited number of patients enrolled and the design being an open‐label study, confirmation by a large‐scale trial is required.
Constitutive Expression of MC1R in HaCaT Keratinocytes Inhibits Basal and UVB‐induced TNF‐α Production
Authors: Garcin Geneviève , Le Gallic Lionel , Stoebner Pierre‐Emmanuel , Guezennec Anne , Guesnet Joelle , Lavabre‐Bertrand Thierry , Martinez Jean , Meunier Laurent
Published: July 2009

Alpha‐melanocyte stimulating hormone (α‐MSH) binds to melanocortin‐1 receptor (MC1R) on melanocytes to stimulate pigmentation and modulate various cutaneous inflammatory responses. MC1R expression is not restricted to melanocytic cells and may be induced in keratinocytes after UVB exposure. We hypothesized that MC1R signaling in keratinocytes, wherein basal conditions are barely expressed, may modulate mediators of inflammation, such as nuclear factor‐kappa B (NF‐κB) and tumor necrosis factor‐alpha (TNF‐α). Therefore, we generated HaCaT cells that stably express human MC1R or the Arg151Cys (R151C) nonfunctional variant. We demonstrate that: (1) the constitutive activity of MC1R results in elevated intracellular cAMP level, reduced NF‐κB activity and decreased TNF‐α transcription; (2) binding of α‐MSH to MC1R and the subsequent increase in cAMP production do not inhibit TNFα‐mediated NF‐κB activation; (3) MC1R signaling is sufficient to strongly inhibit UVB‐induced TNF‐α expression and this inhibitory effect is further enhanced by α‐MSH stimulation. Our findings suggest that the constitutive activity of the G‐protein‐coupled MC1R in keratinocytes may contribute to the modulation of inflammatory events and immune response induced by UV light.
Early Results of Photoselective Vaporization of the Prostate in Medical Control‐failed Patients
Authors: CHANG Shen Kuang , TSUI Ke Hung , LEE Sheng Hui , CHEN Chien Lun , LIN Yu Hsiang , CHANG Phei Lang
Published: July 2009

Objectives: We present here our early results and learning curve for photoselective vaporization of the prostate (PVP) performed by an experienced urologist and we provide an analysis of the morbidity and early functional outcomes.

Methods: Forty‐four patients were selected, from May 2006 to January 2009, who had benign prostate hyperplasia (BPH) accompanied by lower urinary tract symptoms (LUTS). After undergoing PVP for BPH at our hospital, the patients were followed up for approximately 2 years. PVP was performed by the same experienced urologist using potassium‐titanyl‐phosphate (KTP) laser. Baseline characteristics, preoperative and perioperative data, and postoperative complications were evaluated. Regular outpatient department follow‐up was conducted after patients were discharged from the hospital at 1, 4 and 12 weeks.

Results: The mean age of the 44 patients was 71.6 years. The mean prostate volume was 47.52 mL. The mean PVP surgery time was 79.11 min. The mean urinary catheterization time was 23.41 h. Few complications arose after PVP, except that 47.7% of the patients developed pyuria after being discharged from hospital. The average hospital stay was 2.45 days. There were no significant differences in the efficiency of tissue vaporization among the patients.

Conclusion: PVP for BPH has various advantages, including reducing postoperative complications. An experienced urologist can easily perform PVP. However, early results show no significant differences in the efficiency for the PVP technique.
Gastric Neoplasia in Horses
Authors: Taylor S.D. , Haldorson G.J. , Vaughan B. , Pusterla N.
Published: July 2009

Background:Gastric neoplasia of horses is incompletely described.

Objective:Provide history, clinical signs, and clinicopathological and pathological findings associated with gastric neoplasia in horses.

Animals:Twenty‐four horses with gastric neoplasia.

Methods:Retrospective study. History, clinical signs, and clinicopathological and pathologic findings in horses diagnosed histologically with gastric neoplasia were reviewed.

Results:Horses ranged in age from 9 to 25 years (median 18 years at presentation). There was no apparent breed or sex predisposition. The most common presenting complaints were inappetance (17/24), weight loss (14/24), lethargy (7/24), hypersalivation (7/24), colic (5/24), and fever (5/24). The most consistent clinical signs were tachypnea (10/19), decreased borborygmi (8/19), and low body weight (7/17). Useful diagnostic tests included rectal examination, routine blood analysis, gastroscopy, abdominocentesis, and transabdominal ultrasound examination. Anemia was the most common hematologic abnormality encountered (7/19), and hypercalcemia of malignancy was seen in 4/16 horses. Squamous cell carcinoma was the most common tumor identified (19/24), and was most often (14/19) found as a single ulcerated, necrotic mass in the nonglandular portion of the stomach. Other gastric neoplasms encountered were leiomyoma (n=2), mesothelioma (n=1), adenocarcinoma (n=1), and lymphoma (n=1). Metastatic neoplasia was found in 18/23 horses. The median time from onset of clinical signs to death was 4 weeks, and all horses died or were euthanized because of gastric neoplasia.

Conclusions:Squamous cell carcinoma is the most common primary gastric neoplasia in horses. The survival time after diagnosis of gastric neoplasia in horses is short.
Dysregulation of human bestrophin‐1 by ceramide‐induced dephosphorylation
Authors: Xiao Qinghuan , Yu Kuai , Cui Yuan‐yuan , Hartzell H. Criss
Published: July 2009

Best vitelliform macular dystrophy is an inherited autosomal dominant, juvenile onset form of macular degeneration caused by mutations in a chloride ion channel, human bestrophin‐1 (hBest1). Mutations in Best1 have also been linked to several other forms of retinopathy. In addition to mutations, hBest1 dysfunction might come about by disruption of other processes that regulate Best1 function. Here we show that hBest1 chloride channel activity is regulated by ceramide and phosphorylation. We have identified a protein kinase C (PKC) phosphorylation site (serine 358) in hBest1 that is important for sustained channel function. Channel activity is maintained by PKC activators, protein phosphatase inhibitors, or pseudo‐phosphorylation by substitution of glutamic acid for serine 358. When ceramide levels are elevated by exogenous addition of ceramide to the bath, by addition of bacterial sphingomyelinase, or by hypertonic stress, S358 is rapidly dephosphorylated. The dephosphorylation is mediated by protein phosphatase 2A. Hypertonic stress‐induced dephosphorylation is blocked by a dihydroceramide, an inactive form of ceramide, and manumycin, an inhibitor of neutral sphingomyelinase. Our results support a model in which ceramide accumulation during early stages of retinopathy inhibits hBest1 function, leading to abnormal fluid transport across the retina, and enhanced inflammation.
Insights Into Crowding Effects on Protein Stability From a Coarse-Grained Model
Authors: Shen Vincent K. , Cheung Jason K. , Errington Jeffrey R. , Truskett Thomas M.
Published: July 2009

Proteins aggregate and precipitate from high concentration solutions in a wide variety of problems of natural and technological interest. Consequently, there is a broad interest in developing new ways to model the thermodynamic and kinetic aspects of protein stability in these crowded cellular or solution environments. We use a coarse-grained modeling approach to study the effects of different crowding agents on the conformational equilibria of proteins and the thermodynamic phase behavior of their solutions. At low to moderate protein concentrations, we find that crowding species can either stabilize or destabilize the native state, depending on the strength of their attractive interaction with the proteins. At high protein concentrations, crowders tend to stabilize the native state due to excluded volume effects, irrespective of the strength of the crowder-protein attraction. Crowding agents reduce the tendency of protein solutions to undergo a liquid-liquid phase separation driven by strong protein-protein attractions. The aforementioned equilibrium trends represent, to our knowledge, the first simulation predictions for how the properties of crowding species impact the global thermodynamic stability of proteins and their solutions.
Characterizing Ice Crystal Growth Behavior Under Electric Field Using Phase Field Method
Authors: He Zhi Zhu , Liu Jing
Published: July 2009

In this article, the microscale ice crystal growth behavior under electrostatic field is investigated via a phase field method, which also incorporates the effects of anisotropy and thermal noise. The multiple ice nuclei’s competitive growth as disclosed in existing experiments is thus successfully predicted. The present approach suggests a highly efficient theoretical tool for probing into the freeze injury mechanisms of biological material due to ice formation during cryosurgery or cryopreservation process when external electric field was involved.
Numerical Simulation of Au Nanoparticles Effect on the PCR Process
Authors: Chen Chao , Zhang Aili , Zhang Xiaodong , Hu Jun , Xu Lisa X.
Published: July 2009

Gold nanoparticles have been found to greatly enhance the polymerase chain reaction (PCR) specificity and yield in recent studies. However, the underlying mechanism is still unclear, though different hypotheses have already been proposed. In this study, a mass-action based model has been developed to investigate the effect of Au nanoparticles on the two-round PCR results. The great affinity of Au nanoparticles to the single-stranded DNA is taken into consideration. Each nanoparticle is treated as a bioreactor and/or a selector, around which, reaction equations are coupled to simulate the particle effect, and to investigate the key parameters that might influence such an effect. It is assumed that there exists a competing mechanism between the specific and nonspecific bindings, both in the solution and on the particle surface during the reactions. The numerical predictions accord well to the experimental results, and can be used to explain the Au nanoparticles’ effect on the enhancement of the PCR specificity and efficiency.
Electrical Field and Temperature Model of Nonthermal Irreversible Electroporation in Heterogeneous Tissues
Authors: Daniels Charlotte , Rubinsky Boris
Published: July 2009

Nonthermal irreversible electroporation (NTIRE) is a new minimally invasive surgical technique that is part of the emerging field of molecular surgery, which holds the potential to treat diseases with unprecedented accuracy. NTIRE utilizes electrical pulses delivered to a targeted area, producing irreversible damage to the cell membrane. Because NTIRE does not cause thermal damage, the integrity of all other molecules, collagen, and elastin in the targeted area is preserved. Previous theoretical studies have only examined NTIRE in homogeneous tissues; however, biological structures are complex collections of diverse tissues. In order to develop electroporation as a precise treatment in clinical applications, realistic models are necessary. Therefore, the purpose of this study was to refine electroporation as a treatment by examining the effect of NTIRE in heterogeneous tissues of the prostate and breast. This study uses a two-dimensional finite element solution of the Laplace and bioheat equations to examine the effects of heterogeneities on electric field and temperature distribution. Three different heterogeneous structures were taken into account: nerves, blood vessels, and ducts. The results of this study demonstrate that heterogeneities significantly impact both the temperature and electrical field distribution in surrounding tissues, indicating that heterogeneities should not be neglected. The results were promising. While the surrounding tissue experienced a high electrical field, the axon of the nerve, the interior of the blood vessel, and the ducts experienced no electrical field. This indicates that blood vessels, nerves, and lactiferous ducts adjacent to a tumor treated with electroporation will survive, while the cancerous lesion is ablated. This study clearly demonstrates the importance of considering heterogeneity in NTIRE applications.
Biocompatible Ionic Liquids: A New Approach for Stabilizing Proteins in Liquid Formulation
Authors: Vrikkis Regina M. , Fraser Kevin J. , Fujita Kyoko , MacFarlane Douglas R. , Elliott Gloria D.
Published: July 2009

Ionic liquids (ILs) have shown excellent promise as both solutes and solvents for stabilizing proteins at room temperature. Because many modern drugs are protein-based, these stabilizing characteristics have great potential to provide advances in the field of liquid formulation of therapeutic proteins. However, before these developments can be translated into clinical solutions it is essential to establish data related to the biocompatibility of these ILs. The current work investigates the cytotoxicity of several ILs that were rationally synthesized from natural biomolecules and compounds that have already been approved as excipients for drug formulations. The effect of choline dihydrogen phosphate (choline dhp), choline saccharinate, and 1-butyl 3-methyl imidazolium lactate (bmim lactate) on the metabolic activity of a mouse macrophage cell line (J774) was assessed using the reduction in resazurin as an indicator of activity and, by extension, viability. Two formulations of lysozyme (10 mg/ml and 100 mg/ml) in 80 wt % choline dhp (aq) were prepared and the proteins were evaluated for structural stability immediately following formulation and again at 1 month. Equivalent formulations in 0.1 M Na acetate aqueous buffer were evaluated as controls. A differential scanning microcalorimeter (DSC) was used to evaluate the structural stability on the basis of the unfolding temperature and the enthalpy of unfolding, and a micrococcus lysodiekticus activity test was used to evaluate functional activity. All compounds were found to be relatively benign, with toxicity increasing in the order choline dhp<choline saccharinate<bmim lactate. At 1 month lysozyme that had been stored in choline dhp had a higher activity and folded fraction than lysozyme that had been stored in aqueous buffer. These results suggest that biocompatibility and protein stabilization characteristics can be rationally designed into ionic liquids.
Heat Loss Through the Glabrous Skin Surfaces of Heavily Insulated, Heat-Stressed Individuals
Authors: Grahn D. A. , Dillon J. L. , Heller H. C.
Published: July 2009

Insulation reduces heat exchange between a body and the environment. Glabrous (nonhairy) skin surfaces (palms of the hands, soles of the feet, face, and ears) constitute a small percentage of total body surface area but contain specialized vascular structures that facilitate heat loss. We have previously reported that cooling the glabrous skin surfaces is effective in alleviating heat stress and that the application of local subatmospheric pressure enhances the effect. In this paper, we compare the effects of cooling multiple glabrous skin surfaces with and without vacuum on thermal recovery in heavily insulated heat-stressed individuals. Esophageal temperatures (Tes) and heart rates were monitored throughout the trials. Water loss was determined from pre- and post-trial nude weights. Treadmill exercise (5.6 km/h, 9–16% slope, and 25–45 min duration) in a hot environment (41.5°C, 20–30% relative humidity) while wearing insulating pants and jackets was used to induce heat stress (Tes≥39°C). For postexercise recovery, the subjects donned additional insulation (a balaclava, winter gloves, and impermeable boot covers) and rested in the hot environment for 60 min. Postexercise cooling treatments included control (no cooling) or the application of a 10°C closed water circulating system to (a) the hand(s) with or without application of a local subatmospheric pressure, (b) the face, (c) the feet, or (d) multiple glabrous skin regions. Following exercise induction of heat stress in heavily insulated subjects, the rate of recovery of Tes was 0.4±0.2°C/h(n=12), but with application of cooling to one hand, the rate was 0.8±0.3°C/h(n=12), and with one hand cooling with subatmospheric pressure, the rate was 1.0±0.2°C/h(n=12). Cooling alone yielded two responses, one resembling that of cooling with subatmospheric pressure (n=8) and one resembling that of no cooling (n=4). The effect of treating multiple surfaces was additive (no cooling, ΔTes=−0.4±0.2°C; one hand, −0.9±0.3°C; face, −1.0±0.3°C; two hands, −1.3±0.1°C; two feet, −1.3±0.3°C; and face, feet, and hands, −1.6±0.2°C). Cooling treatments had a similar effect on water loss and final resting heart rate. In heat-stressed resting subjects, cooling the glabrous skin regions was effective in lowering Tes. Under this protocol, the application of local subatmospheric pressure did not significantly increase heat transfer per se but, presumably, increased the likelihood of an effect.
Voxelized Model of Interstitial Transport in the Rat Spinal Cord Following Direct Infusion Into White Matter
Authors: Kim Jung Hwan , Astary Garrett W. , Chen Xiaoming , Mareci Thomas H. , Sarntinoranont Malisa
Published: July 2009

Direct tissue infusion, e.g., convection-enhanced delivery (CED), is a promising local delivery technique for treating diseases of the central nervous system. Predictive models of spatial drug distribution during and following direct tissue infusion are necessary for treatment optimization and planning of surgery. In this study, a 3D interstitial transport modeling approach in which tissue properties and anatomical boundaries are assigned on a voxel-by-voxel basis using tissue alignment data from diffusion tensor imaging (DTI) is presented. The modeling approach is semi-automatic and utilizes porous media transport theory to estimate interstitial transport in isotropic and anisotropic tissue regions. Rat spinal cord studies compared predicted distributions of albumin tracer (for varying DTI resolution) following infusion into the dorsal horn with tracer distributions measured by Wood et al. in a previous study. Tissue distribution volumes compared favorably for small infusion volumes (<4 μl). The presented DTI-based methodology provides a rapid means of estimating interstitial flows and tracer distributions following CED into the spinal cord. Quantification of these transport fields provides an important step toward development of drug-specific transport models of infusion.
Frontiers in Biotransport: Water Transport and Hydration
Authors: Aksan Alptekin , Hubel Allison , Bischof John C.
Published: July 2009

Biotransport, by its nature, is concerned with the motions of molecules in biological systems while water remains as the most important and the most commonly studied molecule across all disciplines. In this review, we focus on biopreservation and thermal therapies from the perspective of water, exploring how its molecular motions, properties, kinetic, and thermodynamic transitions govern biotransport phenomena and enable preservation or controlled destruction of biological systems.
A note on noise propagation in street canyons
Authors: Li Kai Ming , Lai Chenly Yuen Cheung
Published: July 2009

The current study examines the propagation of sound in street canyons with geometrically reflecting surfaces. An image source method is a popular numerical model to estimate the propagation of sound energy in a street canyon. This numerical model calculates the total sound energy received at a field point by summing the contributions from individual image sources incoherently. The discrete image source model is generalized by replacing rows of point sources with their respective line sources. An integral formulation is derived, which can be evaluated exactly to give a simple analytical solution. The expression permits rapid computations of the sound energy due to a point source placed in a street canyon. The transient sound energy at a receiver point is also examined. It has been demonstrated that the transient sound energy can be expressed in terms of a standard exponential integral. The Schroeder integration method is then used to calculate the reverberation times, which allow a straightforward assessment of the acoustic environment in street canyons. Indoor and outdoor experiments were conducted to validate the proposed integral formulation. The analytical formulas were also compared with numerical results based on the standard image source method and with published experimental data.
The forced radiation efficiency of finite size flat panels that are excited by incident sound
Authors: Davy John L.
Published: July 2009

The radiation efficiency of an infinite flat panel that radiates a plane wave into a half space is equal to the inverse of the cosine of the angle between the direction of propagation of the plane wave and the normal to the panel. The fact that this radiation efficiency tends to infinity as the angle tends to 90° causes problems with simple theories of sound insulation. Sato calculated numerical values of radiation efficiency for a finite size rectangular panel in an infinite baffle whose motion is forced by sound incident at an angle to the normal from the other side. This paper presents a simple two dimensional analytic strip theory, which agrees reasonably well with Sato’s numerical calculations for a rectangular panel. This leads to the conclusion that it is mainly the length of the panel in the direction of radiation, rather than its width that is important in determining its radiation efficiency. A low frequency correction is added to the analytic strip theory. The theory is analytically integrated over all angles of incidence, with the appropriate weighting function, to obtain the diffuse sound field forced radiation efficiency of a panel.
Developmental factors and the non-native speaker effect in auditory-visual speech perception
Authors: Chen Yuchun , Hazan Valerie
Published: July 2009

The study investigated language and developmental factors in the use of visual information in audiovisual speech perception in speakers from different language backgrounds. Mandarin-Chinese and English adults and 8- to 9-year-old children were presented with /ba/, /da/, and /ga/ tokens spoken by two English and two Mandarin-Chinese speakers. A syllable identification task was presented in auditory-only, visual-only, and audiovisual (congruent and incongruent) conditions in clear and in noise. The results showed an increase in the use of visual information in adults relative to children in both the Chinese and English groups. In addition, a positive correlation between the total visual effect and speechreading performance was found, suggesting that the smaller visual influence in the bimodal condition for children might be accounted by their less sophisticated speechreading ability. In regard to the language factor, it was found that Chinese perceivers use visual information in their audiovisual speech processing to the same extent as English perceivers. Finally, there was evidence for a “non-native speaker effect” (i.e., stronger visual effect for non-native speech stimuli), but only for the English participants. Results from the current study suggest that the visual appearance of individual speakers and the acoustic-phonetic properties of specific languages should be considered in future cross-language studies.
Long-term road traffic noise exposure is associated with an increase in morning tiredness
Authors: de Kluizenaar Yvonne , Janssen Sabine A. , van Lenthe Frank J. , Miedema Henk M. E. , Mackenbach Johan P.
Published: July 2009

This study investigates the association between night time road traffic noise exposure (Lnight) and self-reported sleep problems. Logistic regression was performed in a large population based cohort study (GLOBE), including over 18 000 subjects, to study the association between exposure at the dwelling façade and sleep problems. Measures of sleep problems were collected by questionnaire with two questions: “Do you in general get up tired and not well rested in the morning?” and “Do you often use sleep medication or tranquilizers?” After adjustment for potential confounders, a significant association was found between noise exposure and the risk of getting up tired and not rested in the morning. Although prevalence of medication use was higher at higher noise levels compared to the reference category (Lnight<35 dB), after adjustment for covariates this association was not significant. Long-term road traffic noise exposure is associated with increased risk of getting up tired and not rested in the morning in the general population. This result extends the earlier established relationship between long-term noise exposure and self-reported sleep disturbance assessed with questions that explicitly referred to noise and indicates that road traffic noise exposure during the night may have day-after effects.
Limit cycle oscillations in a nonlinear state space model of the human cochlea
Authors: Ku Emery M. , Elliott Stephen J. , Lineton Ben
Published: July 2009

It is somewhat surprising that linear analysis can account for so many features of the cochlea when it is inherently nonlinear. For example, the commonly detected spacing between adjacent spontaneous otoacoustic emissions (SOAEs) is often explained by a linear theory of “coherent reflection” [Zweig and Shera (1995). J. Acoust. Soc. Am. 98, 2018–2047]. The nonlinear saturation of the cochlear amplifier is, however, believed to be responsible for stabilizing the amplitude of a SOAE. In this investigation, a state space model is used to first predict the linear instabilities that arise, given distributions of cochlear inhomogeneities, and then subsequently to simulate the time-varying spectra of the nonlinear models. By comparing nonlinear simulation results to linear predictions, it is demonstrated that nonlinear effects can have a strong impact on the steady-state response of an unstable cochlear model. Sharply tuned components that decay away exponentially within 100 ms are shown to be due to linearly resonant modes of the model generated by the cochlear inhomogeneities. Some oscillations at linearly unstable frequencies are suppressed over a longer time scale, whereas those that persist are due to linear instabilities and their distortion products.
Design of a non-traditional dynamic vibration absorber
Authors: Cheung Y. L. , Wong W. O.
Published: July 2009

A non-traditional dynamic vibration absorber is proposed for the minimization of maximum vibration velocity response of a vibrating structure. Unlike the traditional damped absorber configuration, the proposed absorber has a linear viscous damper connecting the absorber mass directly to the ground instead of the main mass. Optimum parameters of the proposed absorber are derived based on the fixed-point theory for minimizing the maximum vibration velocity response of a single-degree-of-freedom system under harmonic excitation. The extent of reduction in maximum vibration velocity response of the primary system when using the traditional dynamic absorber is compared with that using the proposed one. Under the optimum tuning condition of the absorbers, it is proved analytically that the proposed absorber provides a greater reduction in maximum vibration velocity response of the primary system than the traditional absorber.
Sound power emitted by a pure-tone source in a reverberation room
Authors: Jacobsen Finn , Molares Alfonso Rodríguez
Published: July 2009

Energy considerations are of enormous practical importance in acoustics. In “energy acoustics,” sources of noise are described in terms of the sound power they emit, the underlying assumption being that this property is independent of the particular environment where the sources are placed. However, it is well known that the sound power output of a source emitting a pure tone or a narrow band of noise actually varies significantly with its position in a reverberation room at low frequencies, and even larger variations occur between different rooms. The resulting substantial uncertainty in measurements of sound power as well as in predictions based on knowledge of sound power is one of the fundamental limitations of energy acoustics. The existing theory for this phenomenon is fairly complicated and has only been validated rather indirectly. This paper describes a far simpler theory and demonstrates that it gives predictions in excellent agreement with the established theory. The results are confirmed by experimental results as well as finite element calculations.
Travel-time sensitivity kernels versus diffraction patterns obtained through double beam-forming in shallow water
Authors: Iturbe Ion , Roux Philippe , Virieux Jean , Nicolas Barbara
Published: July 2009

In recent years, the use of sensitivity kernels for tomographic purposes has been frequently discussed in the literature. Sensitivity kernels of different observables (e.g., amplitude, travel-time, and polarization for seismic waves) have been proposed, and relationships between adjoint formulation, time-reversal theory, and sensitivity kernels have been developed. In the present study, travel-time sensitivity kernels (TSKs) are derived for two source-receiver arrays in an acoustic waveguide. More precisely, the TSKs are combined with a double time-delay beam-forming algorithm performed on two source-receiver arrays to isolate and identify each eigenray of the multipath propagation between a source-receiver pair in the acoustic waveguide. A relationship is then obtained between TSKs and diffraction theory. It appears that the spatial shapes of TSKs are equivalent to the gradients of the combined direction patterns of the source and receiver arrays. In the finite-frequency regimes, the combination of TSKs and double beam-forming both simplifies the calculation of TSK and increases the domain of validity for ray theory in shallow-water ocean acoustic tomography.
Regularization in global sound equalization based on effort variation
Authors: Stefanakis Nick , Sarris John , Jacobsen Finn
Published: July 2009

Sound equalization in closed spaces can be significantly improved by generating propagating waves that are naturally associated with the geometry, as, for example, plane waves in rectangular enclosures. This paper presents a control approach termed effort variation regularization based on this idea. Effort variation equalization involves modifying the conventional cost function in sound equalization, which is based on minimizing least-squares reproduction errors, by adding a term that is proportional to the squared deviations between complex source strengths, calculated independently for the sources at each of the two walls perpendicular to the direction of propagation. Simulation results in a two-dimensional room of irregular shape and in a rectangular room with sources randomly distributed on two opposite walls demonstrate that the proposed technique leads to smaller global reproduction errors and better equalization performance at listening positions outside of the control region compared to effort regularization and compared to a simple technique that involves driving groups of sources identically.
The effect of altered auditory feedback on control of vocal production in budgerigars (Melopsittacus undulatus)
Authors: Osmanski Michael S. , Dooling Robert J.
Published: July 2009

Budgerigars learn their vocalizations by reference to auditory information and they retain the ability to learn new vocalizations throughout life. Auditory feedback of these vocalizations was manipulated in three experiments by training birds to produce vocalizations while wearing small earphones. Experiments 1 and 2 examined the effect of background noise level (Lombard effect) and the effect of manipulating feedback level from self-produced vocalizations (Fletcher effect), respectively. Results show that birds exhibit both a Lombard effect and a Fletcher effect. Further analysis showed that changes in vocal intensity were accompanied by changes in call fundamental frequency and duration. Experiment 3 tested the effect of delaying or altering auditory feedback during vocal production. Results showed subsequent production of incomplete and distorted calls in both feedback conditions. These distortions included changes in the peak fundamental frequency, amplitude, duration, and spectrotemporal structure of calls. Delayed auditory feedback was most disruptive to subsequent calls when the delay was 25 ms. Longer delays resulted in fewer errors.
Experimental jet velocity and edge tone investigations on a foot model of an organ pipe
Authors: Außerlechner Hubert J. , Trommer Thomas , Angster Judit , Miklós András
Published: July 2009

In order to investigate the physical processes involved in the build-up of the sound signal in a labial organ pipe a pipe foot model has been developed. The main important parameters, such as positions of the lower and upper lips, the wind pressure in the pipe foot, and the width of the flue, can be adjusted by means of this model. Moreover, different types of languids and pipe bodies (resonators) can be attached to the model. For the reason of corresponding to a real metal organ pipe these parts of the model are made of a typical alloy used in organ building. The reproducibility of measurements is provided by the micrometer screws applied for the adjustments. Flow and edge tone measurements are carried out with the help of this model. Velocity measurements with different flue widths show that the exit velocity of the jet corresponds to the Bernoulli-velocity and is asymmetrically contracted. At larger distances (>5mm) the velocity distribution can be described by a Gauss-function having linearly increasing width. A mathematical relation of the centerline velocity as a function of the cut-up height L is found. The results of edge tone measurements show differences between previous studies and the present one. No frequency stages (and hysteresis phenomena) are found within the investigated pressure and cut-up range; the frequency modes of the edge tone coexist. The measured frequencies can be described by theoretical models.
Nonlinear parabolic equation model for finite-amplitude sound propagation over porous ground layers
Authors: Leissing Thomas , Jean Philippe , Defrance Jérôme , Soize Christian
Published: July 2009

The nonlinear parabolic equation (NPE) is a time-domain method widely used in underwater sound propagation applications. It allows simulation of weakly nonlinear sound propagation within an inhomogeneous medium. So that this method can be used for outdoor sound propagation applications it must account for the effects of an absorbing ground surface. The NPE being formulated in the time domain, complex impedances cannot be used and, hence, the ground layer is included in the computational system with the help of a second NPE based on the Zwikker–Kosten model. A two-way coupling between these two layers (air and ground) is required for the whole system to behave correctly. Coupling equations are derived from linearized Euler’s equations. In the frame of a parabolic model, this two-way coupling only involves spatial derivatives, making its numerical implementation straightforward. Several propagation examples, both linear or nonlinear, are then presented. The method is shown to give satisfactory results for a wide range of ground characteristics. Finally, the problem of including Forchheimer’s nonlinearities in the two-way coupling is addressed and an approximate solution is proposed.
Analysis of flow-structure interaction in the larynx during phonation using an immersed-boundary method
Authors: Luo Haoxiang , Mittal Rajat , Bielamowicz Steven A.
Published: July 2009

A recently developed immersed-boundary method is used to model the flow-structure interaction associated with the human phonation. The glottal airflow is modeled as a two-dimensional incompressible flow driven by a constant subglottal pressure, and the vocal folds are modeled as a pair of three-layered, two-dimensional, viscoelastic structures. Both the fluid dynamics and viscoelasticity are solved on fixed Cartesian grids using a sharp-interface immersed boundary method. It is found that the vibration mode and frequency of the vocal fold model are associated with the eigenmodes of the structures, and that the transition of the vibration mode takes place during onset of the sustained vibration. The computed glottal waveforms of the volume flux, velocity, and pressure are reasonably realistic. The glottal flow features an unsteady jet whose direction is deflected by the large-scale vortices in the supraglottal region. A detailed analysis of the flow and vocal fold vibrations is conducted in order to gain insights into the biomechanics of phonation.
Adaptive plasticity in brainstem of adult listeners following earplug-induced deprivation
Authors: Munro Kevin J. , Blount Jennifer
Published: July 2009

Previous research has shown that loudness perception is modified in adult listeners following 2 weeks of continuous sensory deprivation or stimulation [Formby, C. et al. (2003). J. Acoust. Soc. Am. 114, 55–58]. However, it is not known if the auditory system undergoes physiological changes or if the listeners simply recalibrate their behavioral criteria such that they become more, or less, conservative following sensory deprivation and stimulation, respectively. The results of this study, comparing threshold of the middle ear acoustic reflex in the two ears of adult listeners after use of a unilateral earplug, are consistent with adaptive plasticity. Acoustic reflexes were measured at a lower sound pressure level in the ear that had been plugged for 7 days. Thus, the effect is consistent with a central gain mechanism mediated by a process within the brainstem.
In Vivo Antibacterial Activity of Vertilmicin, a New Aminoglycoside Antibiotic
Authors: You Xue-Fu , Li Cong-Ran , Yang Xin-Yi , Yuan Min , Zhang Wei-Xin , Lou Ren-Hui , Wang Yue-Ming , Li Guo-Qing , Chen Hui-Zhen , Song Dan-Qing , Sun Cheng-Hang , Cen Shan , Yu Li-Yan , Zhao Li-Xun , Jiang Jian-Dong
Published: July 2009

Vertilmicin is a novel aminoglycoside antibiotic with potent activity against gram-negative and -positive bacteria in vitro. In this study, we further evaluated the efficacy of vertilmicin in vivo in systemic and local infection animal models. We demonstrated that vertilmicin had relatively high and broad-spectrum activities against mouse systemic infections caused byEscherichia coli,Klebsiella pneumoniae,Staphylococcus aureus, andEnterococcus faecalis. The 50% effective doses of subcutaneously administered vertilmicin were 0.63 to 0.82 mg/kg, 0.18 to 0.29 mg/kg, 0.25 to 0.99 mg/kg, and 4.35 to 7.11 mg/kg againstE. coli,K. pneumoniae,S. aureus, andE. faecalisinfections, respectively. The therapeutic efficacy of vertilmicin was generally similar to that of netimicin, better than that of gentamicin in all the isolates tested, and better than that of verdamicin againstE. coli9612 andE. faecalisHH22 infections. The therapeutic efficacy of vertilmicin was further confirmed in local infection models of rabbit skin burn infection and mouse ascending urinary tract infection.