bluuebunny/crossref_metadata_2025 huggingface dataset:
Rhythmic Kinetics of Single Fusion and Fission in a Plant Cell Protoplast
Authors: Thiel Gerhard , Kreft Marko , Zorec Robert
Published: January 2009

Plant cells exhibit a lively activity of exocytosis and endocytosis at the plasma membrane. This is required for cell surface area regulation and also for membrane protein recycling. Although these processes are important for growth and development, they are understood purely with respect to their molecular mechanisms, regulation, spatial organization, and kinetics. According to the classical view, secretory vesicles release all their cargo in one step upon fusing and incorporating into the plasma membrane. Recent studies have shown that this model is oversimplifying the reality. Here we use real‐time patch‐clamp recording to monitor single‐vesicle fusion and fission in order to resolve the kinetic properties of these elementary processes. The data show that single vesicles can, in a rhythmic fashion, make and break contact with the plasma membrane of plant protoplasts. Such oscillations are only possible if the two processes are linked by a distinct feedback system. The fact that similar rhythmic fusion/fission activity is also present in constitutive exocytosis in animal cells implies that the underlying mechanisms appear universal in eukaryotic cells.
Exocytosis of Insulin
Authors: Rozzo Aldo , Meneghel‐Rozzo Tiziana , Delakorda Saša Lipovšek , Yang Shi‐Bing , Rupnik Marjan
Published: January 2009

The aim of this study was to define when an insulin‐positive cell becomes functional in vivo and starts to exocytose insulin in a regulated nutrient‐dependent manner. Insulin‐positive cells appear in embryonic life (midgestation) and complete their maturation, presumably around birth. In order to work with embryonic and newborn endocrine pancreas, we used organotypic slices. The mouse embryonic pancreas slices show high basal insulin release that is not further elevated by high glucose levels. Despite the presence of functional voltage‐activated ion channels, the cells are not electrically active in the presence of secretagogues. At birth, the high basal insulin release drops and, after postnatal day 2, the insulin‐positive cells show both adult‐like bursting electrical activity and hormone release induced by high glucose levels. These properties allowed us to define them as beta cells. Despite the apparent stability of the transcription factor profile reported in insulin‐positive cells during late‐embryonic life, functional beta cells appear only 2 days after birth.
Apical Plasma Membrane Traffic in Superficial Cells of Bladder Urothelium
Authors: Kreft Mateja Erdani , Jezernik Kristijan , Kreft Marko , Romih Rok
Published: January 2009

Superficial urothelial cells that line the urinary bladder accommodate cyclical changes in organ volume while maintaining a permeability barrier between urine and tissue fluids. The specific apical plasma membrane traffic is necessary for their proper function. The composition of the apical plasma membrane is dramatically modified during differentiation of bladder urothelial cells, most notably by assembly of urothelial plaques containing uroplakins. However, the assembly of uroplakins into plaques, their insertion and removal from the apical surface, and the regulation of these processes are still poorly understood. This review examines the traffic (exocytosis/endocytosis) of the apical plasma membrane during differentiation of urothelial cells and focuses on the physiological and clinical significance of the apical plasma membrane traffic in bladder superficial urothelial cells.
Depuration of Striped Venus Clam (Chamelea gallina L.): Effects on Microorganisms, Sand Content, and Mortality
Authors: Maffei M. , Vernocchi P. , Lanciotti R. , Guerzoni M.E. , Belletti N. , Gardini F.
Published: January 2009

ABSTRACT:  This study was focused on the evaluation of the microbiological indices, defined by European legislation, before and after the depuration of clams (Chamelea gallina) landed in category B seawater. The survival of depurated clams and the meat yield were also evaluated. The results obtained from October 2002 to September 2003 evidenced a mean microbial reduction during depuration of 62% for Escherichia coli and 54% for fecal coliforms (FC). All the samples had FC counts below the limit after 24 h depuration with the exception of the August samples. E. coli was found in concentration slightly higher than the legal limit only in the samples of December and January. In August, the E. coli concentration did not decrease during the depuration, while in the other samples significant reduction of E. coli concentration was observed. Salmonella spp. and V. parahaemolyticus were never detected in the clams harvested between March and September. Vibrio alginolyticus was found in the clams harvested in May and September both before and after the depuration process. The viability of clam was not negatively affected by depuration, in fact, an increase of viability was observed with the exception of the samples of April. The meat yield was not influenced by the depurative treatment in C. gallina; the mean value found before depuration, 10.47% (with 1.95 SD), did not significantly vary after the treatment (10.58%, SD 2.07). In conclusion, the depuration conditions can improve the quality of C. gallina; however, its effects on microbiological quality depended on environmental conditions.
Reduction of Oil Absorption in Deep‐Fried, Battered, and Breaded Chicken Patties Using Whey Protein Isolate as a Postbreading Dip: Effect on Flavor, Color, and Texture
Authors: Mah E. , Brannan R.G.
Published: January 2009

ABSTRACT: The effect of the application of whey protein isolate (WPI) solution as a postbreading dip to reduce oil absorption in deep‐fried, battered, and breaded chicken patties on sensory properties was investigated. Chicken patties were battered, breaded with either crackermeal (CMP) or Japanese breadcrumbs (JBP), and dipped into WPI solutions at varying protein concentrations (0%, 2.5%, 5%, and 10%[w/w] WPI) and pH levels (pH 2, 3, and 8). A trained descriptive sensory panel evaluated the patties for 16 attributes relating to appearance, texture, and flavor. Instrumental analysis on the color and texture of the patties was also performed. The only perceivable changes in treated patties were related to color, hardness, and crunchiness. Increasing WPI concentration caused darkening of JBP but made CMP lighter. Patties treated at pH 8 were significantly darker across all WPI concentrations. The presence of WPI increased hardness and crust fracture for CMP but not JBP. Variations in pH levels did not affect texture. Thus, JBP that showed the highest lipid reduction (10% WPI at pH 2) were observed to be darker, less yellow, but did not produce any perceivable changes in hardness or crunchiness, while CMP with the lowest lipid content (5% WPI at pH 2) were lighter, more yellow, harder, and crunchier.
Inactivation of Escherichia coli K‐12 in Apple Juice Using Combination of High‐Pressure Homogenization and Chitosan
Authors: Kumar S. , Thippareddi H. , Subbiah J. , Zivanovic S. , Davidson P.M. , Harte F.
Published: January 2009

ABSTRACT:  Apple juice and apple cider were inoculated with Escherichia coli K‐12 and processed using a high‐pressure homogenizer to study bacterial inactivation. Seven levels of pressure ranging from 50 to 350 MPa were used in the high‐pressure homogenizer. Two types of chitosan (regular and water soluble) with 2 levels of concentration 0.01% and 0.1% were investigated for synergistic effect with high‐pressure homogenization for the bacterial inactivation. E. coli K‐12 inactivation was evaluated as a function of homogenizing pressure at different concentration of 2 types of chitosan in apple juice and cider. High‐pressure homogenization (HPH) induced significant inactivation in the range of 100 to 200 MPa, while thermal inactivation was the primary factor for the bacterial inactivation above 250 MPa. Significant (P < 0.05) 2‐way interactions involving pressure and type of substrate or pressure and chitosan concentration were observed during the study. The homogenization pressure and the incremental quantity of chitosan (both types) acted synergistically with the pressure to give higher inactivation. Significantly (P < 0.05) higher inactivation was observed in apple juice than apple cider at same homogenizing pressure. No effect of type of chitosan was observed on the bacterial inactivation.
A Combination of Grape Seed‐Derived Procyanidins and Gypenosides Alleviates Insulin Resistance in Mice and HepG2 Cells
Authors: Zhang H.‐J. , Ji B.‐P. , Chen G. , Zhou F. , Luo Y.‐C. , Yu H.‐Q. , Gao F.‐Y. , Zhang Z.‐P. , Li H.‐Y.
Published: January 2009

ABSTRACT:  This study investigated the effects of grape seed‐derived procyanidins (GSP), gypenosides (GPE), and combination procyanidins/gypenosides on insulin resistance in mice and HepG2 cells. ICR mice were randomly divided into 2 control and 4 treatment groups. The control mice were to receive either normal diet (ND) or high‐fat diet (HFD), and the treatment groups were fed high‐fat diet with either 80 mg/kg of GSP (GSP80), GPE (GPE80), GSP + GPE (1: 1, GSP40 + GPE40), or 500 mg/kg of metformin for a 6‐wk period. All the groups of mice except the normal control were on high‐fat diet along with fructose (15%) administered in drinking water throughout the period of treatment. An insulin‐resistant HepG2 cell model was developed after 24 h of 5 × 10−7 mol/L insulin incubation. The treatment of GPE80 could significantly reduce the index of insulin resistance (HOMA‐IR) and increase hepatic glycogen concentration, compared with HFD group (P < 0.05). When GSP and GPE were administered simultaneously, synergic effects were observed in decreasing the HOMA‐IR index and serum total cholesterol (TC) level and enhancing glucose tolerance. All treatment groups showed considerable raise of hepatic glucokinase activity (P < 0.05 compared with HFD group). GSP application increased the consumption of extracellular glucose in HepG2 cells. Our data suggest that the combination of GSP and GPE may have functional efficacy in consumers with insulin resistance.
Comparative Analysis of GPCR Crystal Structures†
Authors: Lodowski David T. , Angel Thomas E. , Palczewski Krzysztof
Published: January 2009

The phototransduction cascade is perhaps the best understood model system for G protein‐coupled receptor (GPCR) signaling. Phototransduction links the absorption of a single photon of light to a decrease in cytosolic cGMP. Depletion of the cGMP pool induces closure of cGMP‐gated cation channels resulting in the hyperpolarization of photoreceptor cells and consequently a neuronal response. Many biochemical and both low‐ and high‐resolution structural approaches have been utilized to increase our understanding of rhodopsin, the key molecule of this signaling cascade. Rhodopsin, a member of the GPCR or seven‐transmembrane spanning receptor superfamily, is composed of a chromophore, 11‐cis‐retinal that is covalently bound by a protonated Schiff base linkage to the apo‐protein opsin at Lys296 (in bovine opsin). Upon absorption of a photon, isomerization of the chromophore to an all‐trans‐retinylidene conformation induces changes in the rhodopsin structure, ultimately converting it from an inactive to an activated state. This state allows it to activate the heterotrimeric G protein, transducin, by triggering nucleotide exchange. To fully understand the structural and functional aspects of rhodopsin it is necessary to critically examine crystal structures of its different photointermediates. In this review we summarize recent progress on the structure and activation of rhodopsin in the context of other GPCR structures.
pH‐dependent Interaction of Rhodopsin with Cyanidin‐3‐glucoside. 1. Structural Aspects†
Authors: Yanamala Naveena , Tirupula Kalyan C. , Balem Fernanda , Klein‐Seetharaman Judith
Published: January 2009

Anthocyanins are a class of natural compounds common in flowers and vegetables. Because of the increasing preference of consumers for food containing natural colorants and the demonstrated beneficial effects of anthocyanins on human health, it is important to decipher the molecular mechanisms of their action. Previous studies indicated that the anthocyanin cyanidin‐3‐glucoside (C3G) modulates the function of the photoreceptor rhodopsin. In this paper, we show using selective excitation 1H NMR spectroscopy that C3G binds to rhodopsin. Ligand resonances broaden upon rhodopsin addition and rhodopsin resonances exhibit chemical shift changes as well as broadening effects in specific resonances, in an activation state‐dependent manner. Furthermore, dark‐adapted and light‐activated states of rhodopsin show preferences for different C3G species. Molecular docking studies of the flavylium cation, quinoidal base, carbinol pseudobase and chalcone forms of C3G to models of the dark, light‐activated and opsin structures of rhodopsin also support this conclusion. The results provide new insights into anthocyanin–protein interactions and may have relevance for the enhancement of night vision by this class of compounds. This work is also the first report of the study of ligand binding to a full‐length membrane receptor in detergent micelles by 1H NMR spectroscopy. Such studies were previously hampered by the presence of detergent micelle resonances, a problem overcome by the selective excitation approach.
Glu 87 of Channelrhodopsin‐1 Causes pH‐dependent Color Tuning and Fast Photocurrent Inactivation†
Authors: Tsunoda Satoshi P. , Hegemann Peter
Published: January 2009

Channelrhodopsins (ChR1 and ChR2) are directly light‐gated ion channels acting as sensory photoreceptors in the green alga Chlamydomonas reinhardtii. These channels open rapidly after light absorption and both become permeable for cations such as H+, Li+, Na+, K+ and Ca2+. Km for Ca2+ is 16.6 mm in ChR1 and 18.3 mm in ChR2 whereas the Km values for Na+ are higher than 100 mm for both ChRs. Action spectra of ChR1 peak between 470 and 500 nm depending on the pH conditions, whereas ChR2 peaks at 470 nm regardless of the pH value. Now we created two chimeric ChRs possessing helix 1–5 of ChR1 and 6, 7 of ChR2 (ChR1/25/2), or 1, 2 from ChR1 and 3–7 from ChR2 (ChR1/22/5). Both ChR‐chimera still showed pH‐dependent action spectra shifts. Finally, a mutant ChR1E87Q was generated that inactivated only slowly in the light and showed no spectral shift upon pH change. The results indicate that protonation/deprotonation of E87 in helix 1 alters the chromophore polarity, which shifts the absorption and modifies channel inactivation accordingly. We propose a trimodal counter ion complex for ChR1 but only a bimodal complex for ChR2.
A Tin Oxide Transparent Electrode Provides the Means for Rapid Time‐resolved pH Measurements: Application to Photoinduced Proton Transfer of Bacteriorhodopsin and Proteorhodopsin†
Authors: Tamogami Jun , Kikukawa Takashi , Miyauchi Seiji , Muneyuki Eiro , Kamo Naoki
Published: January 2009

An electrochemical cell was previously reported in which bacteriorhodopsin (BR, purple membrane) was adsorbed on the surface of a transparent SnO2 electrode, and illumination resulted in potential or current changes (Koyama et al., Science 265:762–765, 1994; Robertson and Lukashev, Biophys. J. 68:1507–1517, 1995; Koyama et al., Photochem. Photobiol. 68:400–406, 1998). In this paper, we concluded that pH changes caused by proton transfer by the deposited BR or proteorhodopsin (PR) films lead to the flash‐induced potential change in the SnO2 electrode. Thus, the signals originate from BR and PR acting as light‐driven proton pumps. This conclusion was drawn from the following observations. (1) The relation between the potential of a bare electrode and pH is linear for a wide pH range. (2) The flash‐induced potential changes decrease with an increase in the buffer concentration. (3) The action spectrum of PR agrees well with the absorption spectrum. (4) The present electrode can monitor the pH change in the time range from 10 ms to several hundred milliseconds, as deduced by comparing the SnO2 signal with the signals of pH‐sensitive dyes. Using this electrode system, flash‐induced proton transfer by BR was measured for a wide pH range from 2 to 10. From these data, we reconfirmed various pKa values reported previously, indicating that the present method can give the correct pKa values. This is the first report to estimate these pKa values directly from the proton transfer. We then applied this method to flash‐induced proton transfer of PR. We observed proton uptake followed by release for the pH range from 4 to 9.5, and in other pH ranges, proton release followed by uptake was observed.
Evaluation of newly developed combination therapy of intra‐arterial 5‐fluorouracil and systemic pegylated interferon α‐2b for advanced hepatocellular carcinoma with portal venous invasion: preliminary results
Authors: Kasai Kazuhiro , Kuroda Hidekatsu , Ushio Akira , Sawara Kei , Takikawa Yasuhiro , Suzuki Kazuyuki
Published: January 2009

Aim:  Prognosis is extremely poor for advanced hepatocellular carcinoma (HCC) in patients with portal invasion. The present study evaluated the efficacy of combined intra‐arterial 5‐fluorouracil (5‐FU) and systemic pegylated interferon (PEG‐IFN)α‐2b in patients with advanced HCC.

Methods:  The subjects comprised nine HCC patients with portal vein thrombosis treated using subcutaneous administration of PEG‐IFNα‐2b (50–100 µg on day 1 of every week, for 4 weeks) and intra‐arterial infusion of 5‐FU (250 mg/day for 5 h on days 1–5 of every week, for 4 weeks). For four patients with hepatitis C virus (HCV) infection, oral administration of ribavirin (400–800 mg/day) was added. At the end of every cycle, response to therapy was assessed using Response Evaluation Criteria in Solid Tumors (RECIST) guidelines.

Results:  Partial response (PR) was observed in seven of nine patients, with stable or progressive disease in the remaining two patients. Tumors were resectable in three patients displaying PR after treatment. Tumor markers decreased significantly after therapy. Serum HCV‐RNA titers were markedly decreased and became undetectable in all patients with HCV infection. National Cancer Institute–Common Toxicity Criteria: version 3.0 (NCI‐CTC) grade 3 thrombocytopenia was seen in one case at the end of treatment, but was resolved with cessation of treatment. Other adverse effects were manageable.

Conclusion:  Combination therapy with intra‐arterial 5‐FU and systemic PEG‐IFNα‐2b may be useful as a palliative treatment for patients with advanced HCC. A prospective controlled trial using a larger population of patients with advanced HCC is needed to evaluate this new combination therapy.
HBV genotypes in India: do they influence disease severity?
Authors: Madan Kaushal , Batra Yogesh , Sreenivas Vishnubhatla , Mizokami Masashi , Tanaka Yasuhito , Chalamalasetty Sreenivasa Baba , Panda Subrat K. , Acharya Subrat K.
Published: January 2009

Aims:  Association of HBV genotypes (especially A and D) with severity of liver disease is controversial. We studied the influence of HBV genotypes on liver disease severity among Indian patients.

Methods:  We selected 247 HBV infected patients (42 acute hepatitis, 87 carriers, 44 chronic hepatitis B [CHB], 35 liver cirrhosis [LC] and 40 hepatocellular carcinoma [HCC]). Genotyping of stored sera was performed using genotype‐specific enzyme‐linked immunosorbent assay (ELISA) and restriction fragment length polymorphism (RFLP). The distribution of genotypes in disease states of differing clinical, histological and biochemical severity were compared.

Results:  The most common genotype was D (162/237, 68.3%), followed by A (61, 25.7%) and C (14, 5.9%). The distribution of HBV genotypes between patients with acute hepatitis and CHB (carriers + CHB + LC + HCC), or between carriers and disease states (CHB + LC + HCC), or between mild chronic infection (carriers + CHB) and complications of chronic HBV infection (LC + HCC) was similar. Eighty‐seven patients had liver biopsy; the median histological activity index (HAI) and fibrosis stage at baseline were similar between genotype groups (four [1–9] genotype A [n = 28]), three (2–4) genotype C (n = 4) and four (1–10) genotype D (n = 55); P = 0.33 for HAI score; (0.5 [0–6] genotype A, 0.5 [0–4] genotype C and 1 [0–6] genotype D; P = 0.92 for fibrosis stage). The response to therapy was similar between the genotypes.

Conclusion:  Clinical, histological severity and therapeutic responses are similar among patients with HBV genotypes A and D.
Learning the Dynamic Processes of Color and Light in Interior Design
Authors: Poldma Tiiu
Published: January 2009

Interior environments and their design are profoundly influenced by how designers integrate color and light with form and space. In our increasingly global world, new lighting technologies are changing our perception of color and light and subsequently our interrelationships with one another and with interior space. This alters the choices that we have as designers when we make both color and light decisions. Traditional light and color theories are being challenged with new lighting approaches that are complex, dynamic, and that are changing people's immediate experiences within spaces. Currently, new light technologies alter our perceptual relationships with people and forms, as light, its spectral color, and the forms its affects are more interactive and modulated in real time.

Usually, in interior design coursework, students learn about color and light as static theories that they are then asked to apply within the interior design of spaces in subsequent design studios. Through a presentation and examination of the course “Color and Light in Interior Design,” this paper proposes considering integrating color and light theories with new contexts of dynamic, integrated human experiences of color and light in interior space. Students acquire learning experiences that integrate theory and practice by understanding the complex interrelationships of light, color, and objects in interior spaces as interactive, and by exploring design concepts in actual environments as a laboratory where they can test theories and their own ideas. The course structure is described and the theories underlying the course goals are explored. Color and light theories are considered in the context of emerging technologies and how phenomenological approaches affect our perceptions and experiences in spaces. Student examples of two of the four course projects are presented as these put theories into practice. The discussion shows that light and color theory, when explored in this way, stimulates both comprehensive and creative responses that integrate new technology with aesthetic theory and functional aspects of well–designed light/color solutions. The integrating of practice into theory stimulates reflective thinking and an understanding of situated contexts in interior design problem solving. The course develops emerging necessities of understanding dynamic color/light concepts that contribute to broadening interior design applied knowledge.
Position and Orientation Characteristic Equation for Topological Design of Robot Mechanisms
Authors: Yang Ting-Li , Liu An-Xin , Jin Qiong , Luo Yu-Feng , Shen Hui-Ping , Hang Lu-Bin
Published: January 2009

This paper presents the explicit mapping relations between topological structure and position and orientation characteristic (POC) of mechanism motion output. It deals with (1) the symbolic representation and the invariant property of the topological structure of the mechanism, (2) the matrix representation of POC of mechanism motion output, and (3) the POC equations of serial and parallel mechanisms and the corresponding symbolic operation rules. The symbolic operation involves simple mathematic tools and fewer operation rules and has clear geometrical meaning, so it is easy to use. The POC equations cannot only be used for structural analysis of the mechanism (such as determining POC of the relative motion between any two links of a mechanism and the rank of single-loop kinematic chain and calculating the full-cycle DOF of a mechanism, etc.) but can be used for structural synthesis of the mechanism as well (e.g., structural synthesis of the rank-degenerated serial mechanism, the over constrained single-loop mechanism, and the rank-degenerated parallel mechanism, etc.).
Self-Deployment of a Tape-Spring Hexapod: Experimental and Numerical Investigation
Authors: Aridon G. , Rémond D. , Morestin F. , Blanchard L. , Dufour R.
Published: January 2009

In the framework of developing a future space telescope, this paper focuses on a deployable hexapod equipped with tape-spring coiling devices. It describes the measurement of the platform deployment with a gravity compensation setup. The deployment modeling starts with the formulation of a phenomenological model for a single deployable coiling device. A force-elongation model is built experimentally by measuring the restoring force of such a hysteretic tape-spring actuator. Then, six actuator models are used in parallel to build a complete model of the deployable hexapod. Finally, measured and predicted platform responses are compared. A design of experiments approach highlights that disparities in the restoring force of tape-spring actuators are decisive for deployment success. A regression model is obtained to predict the hexapod’s twist behavior, which is the main indicator of deployment failure. This investigation underlines the requirement of actuator control during deployment.
Formulation of Elastic Interaction Between Bolts During the Tightening of Flat-Face Gasketed Joints
Authors: Alkelani Ali A. , Nassar Sayed A. , Housari Basil A.
Published: January 2009

A novel mathematical model is proposed for studying elastic interaction in gasketed bolted joints. The model predicts the tension changes in tightened bolts due to the subsequent tightening of other bolts in the joint. It also predicts the final clamp load distribution after the completion of joint tightening. The model is used to investigate the effect of various factors on the elastic interaction phenomenon; factors include the gasket thickness, bolt spacing, fastener preload level, and tightening sequence of various bolts. Experimental verification is provided for the validation of the mathematical model. Experimental and analytical results are presented and discussed. The proposed model provides a good prediction of the final clamp load in the joint. Moreover, the proposed model may be used to determine the level of initial bolt tension in each bolt that would be necessary to achieve the desired level of uniform clamp load in the joint at the initial assembly.
A Computational Design Method for a Shape Memory Alloy Wire Actuated Compliant Finger
Authors: Lan Chao-Chieh , Yang You-Nien
Published: January 2009

This paper presents a computational method to design a compliant finger for robotic manipulations. As traditional mechanical fingers require bulky electromagnetic motors and numerous relative moving parts to achieve dexterous motion, we propose a class of fingers; the manipulation of which relies on finger deflections. These compliant fingers are actuated by shape memory alloy (SMA) wires that exhibit high work-density, frictionless, and quiet operations. The combination of compliant members with embedded SMA wires makes the finger more compact and lightweight. Various SMA wire layouts are investigated to reduce their response time while maintaining sufficient output force. The mathematical models of finger deflection caused by SMA contraction are then derived along with experimental validations. As finger shapes are essential to the range of deflected motion and output force, we find its optimal initial shapes through the use of a shape parametrization technique. We further illustrate our method by designing a humanoid finger that is capable of three-dimensional manipulation. Since compliant fingers can be fabricated monolithically, we expect the proposed design method to be utilized for applications of various scales.
Application of Multiparameter Optimization for Robust Product Design
Authors: Herrmann Douglas K.
Published: January 2009

Taguchi optimization or robust design is an effective way to balance rigorous statistical testing and compressed time schedules when engineering a product design. In an effort to define the specifications of the parameters that will eventually control the product output, it is necessary to first identify those parameters that will most likely have the greatest effect on the performance of the system. Once the parameters have been narrowed down, it is then the job of the testing to identify the levels of each parameter to ensure robust performance of the system. Without the efficiencies of the designed experiments described as robust design, it would be impossible within the constraints of a tight design schedule to properly optimize a system design for reliable performance. The usefulness of the Taguchi optimization is especially important when a design will be subjected to a wide variety of noises. It is for this reason that Taguchi techniques fit well in the world of paper handling product design. This paper discusses how these techniques were used to optimize a production printer finishing module. It steps through the process from identifying the parameters and setting up the test to the additional evaluation of parameters to meet the design constraints of the physical hardware.
Actuator Gain Distributions to Analytically Meet Specified Performance Capabilities in Serial Robot Manipulators
Authors: Rios Oziel , Tesar Delbert
Published: January 2009

A serial robotic manipulator arm is a complex electromechanical system whose performance is characterized by its actuators. The actuator itself is a complex nonlinear system whose performance can be characterized by the speed and torque capabilities of its motor, and its accuracy depends on the resolution of the encoder as well as its ability to resist deformations under load. The mechanical gain associated with the transmission is critical to the overall performance of the actuator since it amplifies the motor torque, thus improving the force capability of the manipulator housing it, reduces the motor speed to a suitable output speed operating range, and amplifies the stiffness improving the precision under load of the overall system. In this work, a basic analytic process that can be used to manage the actuator gain parameter to obtain an improved arm design based on a set of desired/required performance specifications will be laid out. Key to this analytic process is the mapping of the actuator parameters (speed, torque, stiffness, and encoder resolution) to their effective values at the system output via the mechanical gains of the actuators as well as the effective mechanical gains of the manipulator. This forward mapping of the actuator parameters allows the designer to determine how each of the parameters influences the functional capacity of the serial manipulator arm. The actuator gains are then distributed along the effective length of the manipulator to determine their effects on the performance capabilities of the system. The analytic formulation is also demonstrated to be effective in addressing the issue of configuration management of serial robotic manipulators where the goal is to assemble a system that meets some required performance specifications. To this end, two examples demonstrating a solution of the configuration management problem are presented. The analytic process developed based on the mapping of the mechanical parameters of the actuator to their effective values at the system output is shown to dramatically reduce the effort in the initial phases of the design process, meaning that the number of design iterations can be dramatically reduced.
Observations of low-frequency temporal and spatial coherence in shallow water
Authors: DeFerrari Harry A.
Published: January 2009

Measurements of temporal and spatial coherence are most always confounded by the presence of multipath interference. Here, two sets of data are presented that allow separation of arrivals from individual propagating modes and then unambiguous computations of temporal and spatial coherence free of multipath effects. A consistent finding for surface reflected bottom reflected (SRBR) modes is that lower order mode are more coherent in both time and space than higher order (steeper) modes. Also, SRBR paths are much more coherent than refracted bottom reflected mode groups that cannot be separated in time and are affected by multi-mode interference.
Spectral and temporal integration of brief tones
Authors: Hoglund Evelyn M. , Feth Lawrence L.
Published: January 2009

Both spectral and temporal integration of tones have been explored in detail, but integration of tones varying across both dimensions has received little attention. This study explores temporal integration of tone pulses that vary over a range of frequencies. Baseline thresholds were obtained for both spectral and temporal integration with the same signals and compared with prior research. The signals were then varied on both dimensions in several ways: with equivalent spectral and temporal step sizes, different spectral and temporal step sizes, and a random pattern of frequency presentation. The data were also analyzed by spectral step size, temporal step size, frequency range, direction and slope of frequency change, and predictability. The spectral and temporal integration conditions showed that the current procedures and signals yielded the same improvement in detection thresholds as prior studies. The spectrotemporal integration conditions showed the improvement for overall detection of the signals to be limited by spectral integration, with improvement related primarily to the number of tones, regardless of timing and frequency. Surprisingly, trial-by-trial random presentation of signal frequencies did not negatively influence detection. These results support the multiple looks hypothesis [Viemeister, N. F. and Wakefield, G. H. (1991). “Temporal integration and multiple looks,” J. Acoust. Soc. Am. 90, 858–865] as applied to spectrotemporal integration.
Space domain complex envelopes: Definition and a spatial modulation method
Authors: Park Choon-Su , Kim Yang-Hann
Published: January 2009

When one visualizes a sound field as a means of treating noise sources, a detailed variation of the sound field is not required. It is sufficient to see source locations and overall variation of the field. A complex envelope in space can provide adequate information that one wishes to get because an envelope shows a gross change in signal. In other words, to interpret overall variation of sound fields in terms of a complex envelope is attempted. To achieve this objective, spatial complex envelopes have been defined firstly, and then a spatial modulation method to obtain the envelope has been theoretically developed and verified.
Comparison of stationary acoustic monitoring and visual observation of finless porpoises
Authors: Kimura Satoko , Akamatsu Tomonari , Wang Kexiong , Wang Ding , Li Songhai , Dong Shouyue , Arai Nobuaki
Published: January 2009

The detection performance regarding stationary acoustic monitoring of Yangtze finless porpoises Neophocaena phocaenoides asiaeorientalis was compared to visual observations. Three stereo acoustic data loggers (A-tag) were placed at different locations near the confluence of Poyang Lake and the Yangtze River, China. The presence and number of porpoises were determined acoustically and visually during each 1-min time bin. On average, porpoises were acoustically detected 81.7±9.7% of the entire effective observation time, while the presence of animals was confirmed visually 12.7±11.0% of the entire time. Acoustic monitoring indicated areas of high and low porpoise densities that were consistent with visual observations. The direction of porpoise movement was monitored using stereo beams, which agreed with visual observations at all monitoring locations. Acoustic and visual methods could determine group sizes up to five and ten individuals, respectively. While the acoustic monitoring method had the advantage of high detection probability, it tended to underestimate group size due to the limited resolution of sound source bearing angles. The stationary acoustic monitoring method proved to be a practical and useful alternative to visual observations, especially in areas of low porpoise density for long-term monitoring.
Pitch discrimination interference: The role of ear of entry and of octave similarity
Authors: Gockel Hedwig E. , Hafter Ervin R. , Moore Brian C. J.
Published: January 2009

Gockel et al. [(2004). J. Acoust. Soc. Am. 116, 1092–1104] reported that discrimination of the fundamental frequency (F0) of two sequentially presented complex tones (the target) was impaired when an additional complex tone (the interferer) was presented simultaneously with and to the same ear as the target, even though the target and interferer were filtered into separate frequency regions. This pitch discrimination interference (PDI) was greatest when the target and interferer had similar F0s. The current study examined the role of relative ear of entry of the target and interferer and whether the dependence of the PDI effect on the relative F0 of target and interferer is based on pitch height (F0 as such) or pitch chroma (the musical note). Sensitivity (d′) was measured for discrimination of the F0 of a target with a nominal F0 of 88 Hz, bandpass filtered from 1375 to 1875 Hz. The interferer was bandpass filtered from 125 to 625 Hz. The contralateral interferer produced marked PDI, but smaller than for ipsilateral presentation. PDI was not larger when the interferer’s F0 was twice the nominal target F0 than when it was a factor of 1.9 or 2.1 higher.
Basin-scale time reversal communications
Authors: Song H. C. , Kuperman W. A. , Hodgkiss W. S.
Published: January 2009

During November 1994, broadband acoustic signals were transmitted from a 75-Hz source to a 20-element, 700-m vertical array at approximately 3250km range in the eastern North Pacific Ocean as part of the acoustic engineering test (AET) of the acoustic thermometry of ocean climate program [Worcester et al., J. Acoust. Soc. Am. 105, 3185–3201 (1999)]. The AET tomography signal can be treated as a binary-phase shift-keying communication signal with an information rate of 37.5bits∕s. With the multipath arrivals spanning 5–8sec, these data represent an extreme case of intersymbol interference. The AET array data are processed using time reversal combined with frequent channel updates to accommodate channel variations over the 20-min long reception, followed by a single channel decision-feedback equalizer. The almost error-free performance using all 20 array elements demonstrates the feasibility of time reversal communications at basin scale. Further, comparable performance of single receive element communications integrating over multiple transmissions indicates that the ocean provided temporal diversity that is as effective as the spatial diversity provided by the array.
Acoustic, psychophysical, and neuroimaging measurements of the effectiveness of active cancellation during auditory functional magnetic resonance imaging
Authors: Hall Deborah A. , Chambers John , Akeroyd Michael A. , Foster John R. , Coxon Ron , Palmer Alan R.
Published: January 2009

Functional magnetic resonance imaging (fMRI) is one of the principal neuroimaging techniques for studying human audition, but it generates an intense background sound which hinders listening performance and confounds measures of the auditory response. This paper reports the perceptual effects of an active noise control (ANC) system that operates in the electromagnetically hostile and physically compact neuroimaging environment to provide significant noise reduction, without interfering with image quality. Cancellation was first evaluated at 600Hz, corresponding to the dominant peak in the power spectrum of the background sound and at which cancellation is maximally effective. Microphone measurements at the ear demonstrated 35dB of acoustic attenuation [from 93to58dB sound pressure level (SPL)], while masked detection thresholds improved by 20dB (from 74to54dB SPL). Considerable perceptual benefits were also obtained across other frequencies, including those corresponding to dips in the spectrum of the background sound. Cancellation also improved the statistical detection of sound-related cortical activation, especially for sounds presented at low intensities. These results confirm that ANC offers substantial benefits for fMRI research.
Interest of the attenuation coefficient in multiparametric high frequency ultrasound investigation of whole blood coagulation process
Authors: Callé Rachel , Plag Camille , Patat Frédéric , Ossant Frédéric
Published: January 2009

Previous studies [R. Libgot, F. Ossant, Y. Gruel, P. Lermusiaux, and F. Patat, Proc.-IEEE Utrason. Symp. 4, 2259–2262 (2005); R. Libgot-Callé, F. Ossant, Y. Gruel, P. Lermusiaux, and F. Patat, Ultrasound Med. Biol. 34, 252–264 (2008); F. Ossant, R. Libgot, P. Coupé, P. Lermusiaux, and F. Patat, Proc.-IEEE Ultrason. Symp. 2, 846–849 (2004)] showed the potential of an in vitro high frequency ultrasound (beyond 20MHz) device to describe the blood clotting process. The parameters were simultaneously estimated in double transmission (DT) with the calculation of the velocity of longitudinal waves and in backscattering (BS) modes with the estimation of the integrated BS coefficient and the effective scatterer size. The aim of the present study was to show how the integrated attenuation coefficient (IAC) assessed in DT mode could provide additional information on this process, especially regarding the fibrin polymerization which is an important part of the coagulation process. A characteristic time ta of the variations in IAC that could be linked to fibrin formation was identified.
Pitfalls in behavioral estimates of basilar-membrane compression in humans
Authors: Wojtczak Magdalena , Oxenham Andrew J.
Published: January 2009

Psychoacoustic estimates of basilar-membrane compression often compare on- and off-frequency forward masking. Such estimates involve assuming that the recovery from forward masking for a given signal frequency is independent of masker frequency. To test this assumption, thresholds for a brief 4-kHz signal were measured as a function of masker-signal delay. Comparisons were made between on-frequency (4kHz) and off-frequency (either 2.4 or 4.4kHz) maskers, adjusted in level to produce the same amount of masking at a 0-ms delay between masker offset and signal onset. Consistent with the assumption, forward-masking recovery from a moderate-level (83dB SPL) 2.4-kHz masker and a high-level (92dB SPL) 4.4-kHz masker was the same as from the equivalent on-frequency maskers. In contrast, recovery from a high-level (92dB SPL) 2.4-kHz forward masker was slower than from the equivalent on-frequency masker. The results were used to simulate temporal masking curves, taking into account the differences in on- and off-frequency masking recoveries at high levels. The predictions suggest that compression estimates assuming frequency-independent masking recovery may overestimate compression by as much as a factor of 2. The results suggest caution in interpreting forward-masking data in terms of basilar-membrane compression, particularly when high-level maskers are involved.
Within- and across-channel factors in the multiband comodulation masking release paradigm
Authors: Grose John H. , Buss Emily , Hall Joseph W.
Published: January 2009

Maskers made up of comodulated narrow bands of noise can result in a signal detection advantage due to both within- and across-channel processes. The purpose of this study was to determine whether contributions from these processes could be differentiated on the basis of two stimulus manipulations: (1) onset/offset asynchrony across bands and (2) introduction of a random temporal fringe surrounding the comodulated bands. The hypothesis was that only masking release due to across-channel processing would be disrupted by these manipulations. Five-band comodulated maskers were constructed, and the availability of within- and across-channel cues was varied by adjusting the frequency spacing of the bands; both logarithmic and linear spacings were tested. The signal was a 1kHz pure tone. Onset/offset asynchrony had different effects depending on the characteristics of the asynchrony. The results were consistent with an interpretation that across-channel, but not within-channel, masking release was disrupted when the flanking bands were presented continuously and the on-signal band was gated. However, the results suggested that both the across-channel and the within-channel masking release were disrupted in conditions where the on-signal band was continuous and the flanking bands were gated on, as well as in conditions where a random temporal fringe was present.
Speech enhancement with multichannel Wiener filter techniques in multimicrophone binaural hearing aids
Authors: Van den Bogaert Tim , Doclo Simon , Wouters Jan , Moonen Marc
Published: January 2009

This paper evaluates speech enhancement in binaural multimicrophone hearing aids by noise reduction algorithms based on the multichannel Wiener filter (MWF) and the MWF with partial noise estimate (MWF-N). Both algorithms are specifically developed to combine noise reduction with the preservation of binaural cues. Objective and perceptual evaluations were performed with different speech-in-multitalker-babble configurations in two different acoustic environments. The main conclusions are as follows: (a) A bilateral MWF with perfect voice activity detection equals or outperforms a bilateral adaptive directional microphone in terms of speech enhancement while preserving the binaural cues of the speech component. (b) A significant gain in speech enhancement is found when transmitting one contralateral microphone signal to the MWF active at the ipsilateral hearing aid. Adding a second contralateral microphone showed a significant improvement during the objective evaluations but not in the subset of scenarios tested during the perceptual evaluations. (c) Adding the partial noise estimate to the MWF, done to improve the spatial awareness of the hearing aid user, reduces the amount of speech enhancement in a limited way. In some conditions the MWF-N even outperformed the MWF possibly due to an improved spatial release from masking.
Measuring hybrid passive-active sound absorption of a microperforated liner at oblique incidence
Authors: Cobo Pedro , Cuesta María
Published: January 2009

The performance of hybrid passive-active absorbers at normal incidence has been previously demonstrated. However, their feasibility in realistic environments remains to be confirmed. This paper proposes a hybrid passive-active liner absorbing at oblique incidence. The passive absorber is a 2.44×2.44×1 mm3 microperforated panel backed by a 5 cm deep air layer and a rigid ending. An active multichannel cell, composed of five single-input single-output controllers, releases the sound pressure at the entrance of the air cavity in a reduced area of the microperforated panel absorber. Hybrid passive/active absorption of the prototype is measured in an anechoic room up to a maximum incidence angle of 21°. For instance, at 20° such a system is able to provide an average absorption of 94% between 266 and 1500 Hz. In addition, the performance that would provide such a hybrid absorber in a reverberant room has been quantified theoretically by an index describing the active-to-passive reverberation time ratio in terms of the active-to-passive absorption area and absorption coefficient ratios. The proposed prototype, implementing 7% of the active proportion area, would afford a reverberation time reduction between 77.5% and 12% from 100 to 500 Hz.