bluuebunny/crossref_metadata_2025 huggingface dataset:
Audit of the use of antimicrobial prophylaxis in nasal surgery at a specialist Australian hospital
Authors: Colgan Stephen J. , Mc Mullan Celene , Davies Geoffrey E. , Sizeland Andrew M.
Published: December 2005

Background:  In 2002−03 a retrospective audit of the use of surgical antimicrobial prophylaxis (AMP) for elective nasal surgery was undertaken at the Royal Victorian Eye and Ear Hospital (RVEEH). The RVEEH is a publicly funded teaching hospital that provides specialist eye, nose and throat medicine in Victoria, Australia. The aim of the audit was to determine the extent to which the use of antimicrobial prophylaxis in the hospital was consistent with Australian and international evidence‐based guidelines and if there was a need for the hospital to develop internal guidelines for the use of AMP.

Methods:  The histories of 500 consecutive patients who had undergone nasal surgery within the study period of August 2001 and July 2002 were examined. The data collected from these histories included information such as the patients’ age, gender, diagnosis, surgical procedure performed, antimicrobial agents used, and the length of follow up and a range of factors shown in previous studies to increase the risk of surgical site infection.

Results:  A total of 306 (72.86%) patients were found to have received antimicrobial agents either prior to admission, during admission or on discharge. Only 24 patients (5.71%) were administered antimicrobials immediately prior to surgery and at no other time.

Conclusions:  The findings of this study support the need for further research to examine the appropriateness of the use of AMP at the RVEEH and the need for internal guidelines for its use.
Weeding techniques in transplanted and direct wet‐seeded rice in Pakistan
Authors: BALOCH MOHAMMAD SAFDAR , HASSAN GUL , MORIMOTO TETSUO
Published: December 2005

Field studies were undertaken to explore the weed management strategies for transplanted and direct wet‐seeded rice in the Dera Ismail Khan district of North‐west Frontier Province, Pakistan. The experimental design was a randomized complete block with a split plot arrangement. The main plots consisted of two planting techniques (transplantation and direct seeding), while weed control practises assigned to the subplots included the use of the granular herbicide Sunstar 15WG (ethoxy sulfuron), Machete 60EC (butachlor), conventional hand weeding, and the weedy check (untreated control). Data were recorded on weed dynamics and the agronomic parameters of the rice crop. Economic analyses on the data were also run. The weed density and biomass were lower in the transplantation plots than the direct‐seeding plots. The herbicides ethoxy sulfuron and butachlor reduced the density over the weedy check, with a density comparable to hand weeding in 2002, but slightly higher in 2003. As a result of weed management by hand weeding and herbicides, the paddy yield and its components were significantly higher for the transplanted method compared to the direct‐seeded method. The comparable yield of herbicides with hand weeding offers an option for the use of herbicides as an alternative management tool. In light of our findings, it is concluded that for good economic returns, rice crops may be transplanted rather than direct‐seeded. The herbicides ethoxy sulfuron and butachlor offer a weed control cover comparable with hand weeding under the transplantation method, while butachlor is good for controlling weeds even under the direct‐seeded conditions in the agroclimatic conditions of the area.
A molecular phylogeny of wild and cultivated Echinochloa in East Asia inferred from non‐coding region sequences of trnT‐L‐F
Authors: YAMAGUCHI HIROFUMI , UTANO AYA , YASUDA KENTARO , YANO AZUSA , SOEJIMA AKIKO
Published: December 2005

The phylogenetic relationship among 30 accessions belonging to nine species of the genus Echinochloa Beauv. was studied on the basis of the sequence of three non‐coding regions (trnT‐L, trnL‐F intergenic spacers, and trnL intron) of chloroplast DNA (cpDNA). A strict consensus parsimonious tree of the three most parsimonious trees derived from 25 polymorphic sites (six indels and 19 substitutions) in the total sequences, ranging from 1715–1760 bp, represented five groups: (i) Echinochloa oryzicola Vasing. and Echinochloa stagnina Beauv. from Thailand; (ii) Echinochloa crus‐galli Beauv. complex; (iii) Echinochloa crus‐pavonis Schult; (iv) Echinochloa colonum Link. and Echinochloa frumentacea Link.; and (v) the African species, Echinochloa obtusiflora Stapf and Echinochloa stagnina. Japanese barnyard millet (Echinochloa esculenta H. Scholz) and various weedy varieties of E. crus‐galli and Echinochloa oryzoides Fritsch had quite similar sequences and formed the E. crus‐galli complex, which was characterized by six substitutions. A cultivated form of E. oryzicola (Mosuo barnyard millet) and various morphological and agronomical forms of E. oryzicola were characterized by two indels. Indian barnyard millet (E. frumentacea) and its wild counterpart (E. colonum) were characterized by five substitutions. Domestication as millets and adaptation to paddy environments as mimic weeds might occur after the divergence of species in the Asian Echinochloa.
Marsupialization of fistulotomy and fistulectomy wounds improves healing and decreases bleeding: a randomized controlled trial
Authors: Pescatori M. , Ayabaca S. M. , Cafaro D. , Iannello A. , Magrini S.
Published: December 2005

Background  Marsupialization of anal fistulotomy/fistulectomy wound leaves less raw unepithelialized tissue. The suture results in a more rapid healing and is likely to reduce the risk of bleeding but at the cost of an increased pain and infection. The aim of this prospective study was to compare the outcomes of marsupialization and open wound.

Methods  Forty‐six consecutive patients with anal fistulae were recruited in a randomized controlled trial. Fistula tracks were treated by fistulotomy and/or fistulectomy. The resulting wounds were marsupialized to the skin edges with locking continuous absorbable sutures (M group) or left open (O group). The clinical outcome was then evaluated. The intra‐operative effect of the suture on wound size was recorded as well as the postoperative pain using a 0–10 visual analogue scale (VAS) and the occurrence of both wound bleeding and infection.

Results  Twenty‐two patients were randomized to the M group and 24 to the O group. There were no differences in the age, sex and fistula type between the groups. Mean follow‐up times were 10.5 and 13.8 months, respectively. No significant difference was observed in postoperative pain, the VAS being 3.5 ± 1.5 in the M group and 3.4 ± 1.6 in the O group at 12 h (mean ± s.e.m.; n.s). The marsupialization nearly halved the size of the wound intra‐operatively from an area of 1749 ± 66 mm2 to 819 ± 38 mm2 (P < 0.001), which subsequently decreased to 217 ± 15 mm2 after 4 weeks (P < 0.01). No significant reduction of wound size was observed in the O group (from 1171 ± 31 mm2 to 543 ± 19; n.s). Bleeding occurred less frequently in M group than in O group (36%vs 46%, P < 0.05), whereas the difference in the postoperative sepsis rate was not significant, being 14% in M vs 21% in the O group. Three reinterventions were needed in both groups due to wound sepsis.

Conclusion  Marsupialization after fistulotomy/fistulectomy significantly reduces the size of the wound and the risk of bleeding, without increasing postoperative pain and sepsis.
The relationship of obesity to the complications of diverticular disease
Authors: Dobbins C. , DeFontgalland D. , Duthie G. , Wattchow D. A.
Published: December 2005

Objective  Diverticular disease is common in our community. Most patients remain asymptomatic and the development of diverticular complications is rare. A common clinical observation is that patients presenting with complications of diverticular disease are obese. The aim of this study was to examine the relationship of obesity to the complications of diverticular disease.

Methods  The study was based on a retrospective case note review conducted at the Flinders Medical Centre between 1/7/1998 and 30/6/2003. Patients were identified using ICD codes and their body mass index (BMI) calculated. Controls were taken randomly from the colonoscopy database at The Flinders Medical Centre. Patients were divided into four groups, those admitted with diverticular perforation or abscess, recurrent diverticulitis, a single episode of diverticulitis and a control group of patients with uncomplicated diverticulosis. The mean BMI for each group was calculated. Statistical analysis was performed by one way anova test with significance set at P < 0.05.

Results  Sixty‐one patients were studied, including 16 patients with perforated diverticular disease, 11 randomly selected with recurrent diverticulitis, 16 patients with a single episode of diverticulitis and 18 controls. The control group had a significantly lower BMI than patients presenting with perforation (P = 0.001) or recurrent diverticulitis (P = 0.002). There was no significant difference between the control group and patients with a single episode of diverticulitis (P = 1.0).

Conclusion  The study showed that patients with perforations and recurrent diverticulitis are significantly more obese than those who remain asymptomatic or have one episode. The aetiological relationship between obesity and diverticular complications remain unclear.
Does gum chewing reduce postoperative ileus following open colectomy for left‐sided colon and rectal cancer? – a prospective randomized controlled trial
Authors: Quah H. M. , Samad A. , Neathey A. J. , Hay D. J. , Maw A.
Published: December 2005

Objective  Postoperative ileus is common after colorectal resection and can prolong hospital stay. Gum chewing, a type of sham feeding, may to stimulate gut motility via cephalic‐vagal stimulation, and thereby reduce the length of ileus. This study aimed to determine whether gum chewing in the immediate postoperative period facilitated recovery from ileus following resection for left‐sided colorectal cancer.

Methods  In a prospective randomized control trial, 38 patients undergoing open surgery for left‐sided colorectal cancer were allocated to standard postoperative care (control group, n = 19) or to standard postoperative care plus the immediate use of chewing gum (treatment group, n = 19).

Result  Control patients passed flatus by mean of 2.7 days (SD 1.0) and faeces by 3.9 days (SD 1.5); for the treatment group, this was 2.4 days (SD 1.0) and 3.2 days (SD 1.5) respectively, (NS, P = 0.56 and P = 0.38). Length of hospital stay was 11.1 days (SD 7.3) in control group and 9.4 days (SD 2.5) in the treatment group (NS, P = 0.75).

Conclusion  The addition of gum chewing to a standardized postoperative regimen did not reduce the period of postoperative ileus or shorten length of stay following open surgery for left‐sided colorectal cancer.
Nuclear microsatellite DNA markers for New Zealand kiwi (Apteryx spp.)
Authors: SHEPHERD L. D. , LAMBERT D. M.
Published: December 2005

Kiwi (Apterygidae) is an endemic New Zealand avian family comprising five species whose conservation is actively managed. We present five polymorphic microsatellite DNA loci isolated from North Island brown kiwi (Apteryx mantelli). In addition, we demonstrate cross‐amplification, and in some cases, polymorphism, of these microsatellite DNA loci in four other kiwi species. Therefore, these markers may be broadly applicable to conservation genetic studies within this family.
Characterization and PCR multiplexing of polymorphic microsatellite loci in cashew (Anacardium occidentale L.) and their cross‐species utilization
Authors: CROXFORD A. E. , ROBSON M. , WILKINSON M. J.
Published: December 2005

Cashew (Anacardium occidentale L.) is the most economically important tropical nut crop in the world, and yet there are no sequence tagged site (STS) markers available for its study. Here we use an automated, high‐throughput system to isolate cashew microsatellites from a non‐enriched genomic library blotted onto membranes at high density for screening. Sixty‐five sequences contained a microsatellite array, of which 21 proved polymorphic among a closely related seed garden population of 49 genotypes. Twelve markers were suitable for multiplex analysis. Of these, 10 amplified in all three related tropical tree species tested: Anacardium microcarpum, Anacardium pumilum and Anacardium nanum.
Characterization of polymorphic microsatellite loci in a traditional Chinese medicinal plant, Gastrodia elata
Authors: XU YANQIN , WANG YING , LI ZUOZHOU , BAO ZHAOXIA , ZHOU JIANFENG , HUANG HONGWEN
Published: December 2005

Genetic characterization of germplasm resource is essential for the conservation and efficient utilization of a traditional Chinese medicinal plant, Gastrodia elata. Thirty‐two primer pairs flanking microsatellite repeats were designed and tested using 32 individuals from eight wild populations. A total of 13 microsatellite loci were found highly polymorphic, with three to 10 alleles per locus and gene diversity ranging from 0.400 to 0.841. These microsatellites have been directly applied to the ongoing population and conservation genetics studies.
Six polymorphic microsatellite loci in the Japanese Spanish mackerel, Scomberomorus niphonius
Authors: YOKOYAMA EMI , SAKAMOTO TAKASHI , SUGAYA TAKUMA , KITADA SHUICHI
Published: December 2005

Six polymorphic microsatellite loci were isolated for genetic structure studies of the Japanese Spanish mackerel, Scomberomorus niphonius, a severely exploited marine fish species. The number of observed alleles for each locus ranged from seven to 41, and the values of expected and observed heterozygosities were 0.546–0.946 and 0.602–1.000, respectively. These microsatellite markers should prove to be a useful tool for estimating the population genetic structure and genetic variability of Japanese Spanish mackerel.
Severity of spoilage storage rots of white yam (Dioscorea rotundata Poir.)
Authors: Aboagye‐Nuamah F. , Offei S.K. , Cornelius E.W. , Bancroft R.D.
Published: December 2005

Severity of storage rots in different sections of white yam tubers (Dioscorea rotundata Poir.) was investigated. Yam samples with rots were collected from a yam barn and from selected markets in Accra, Ghana, to identify the most predominant pathogens associated with the rots. Nine fungal spoilage microorganisms, including Aspergillus flavus, Aspergillus niger, Botryodiplodia theobromae, Fusarium culmorum, Fusarium oxysporium, Fusarium sp., Penicillium brevi‐compactum, Penicillium sp. and Rhizopus stolonifer and a bacterium species Erwinia carotovora were identified. The mean incidence of occurrence of the organisms on rotten tissues ranged from 1.2% to 28.5%. Of the 10 microorganisms isolated, B. theobromae, F. oxysporium and R. stolonifer were the most frequently encountered spoilage microorganisms in the markets. E. carotovora, Fusarium solani and Penicillium sp. were relatively sparse (incidence not exceeding 3%) compared to the other yam spoilage microorganisms. The surface area and weight of necrotic tissue induced by the spoilage fungi in the various zones of the tubers over a 28‐day storage period were assessed. All the spoilage microorganisms produced rots in the yams, although to different degrees. The severity of the rots increased in weight and area over the period when the tubers were in store but were normally not significantly different in the zones of tubers. There was, however, a linear progression of rots in the various zones of the yam tubers. Although there was generally no significant (P ≥ 0.05) difference in the severity of rots induced by the different microorganisms in the tubers, R. stolonifer commonly induced more rot in the zones of the tubers compared to B. theobromae and F. oxysporium.
RAPID ENUMERATION OF ENTEROBACTER SAKAZAKII IN RECONSTITUTED MILK FORMULA BY FLUOROGENIC MOST‐PROBABLE‐NUMBER ASSAY USING 96‐WELL MICROTITER PLATE
Authors: OH SE‐WOOK , KANG DONG‐HYUN
Published: December 2005

A new method was developed to rapidly monitor the Enterobacter sakazakii viable counts in reconstituted infant milk formula. Ninety six–well microtiter plates were used to perform a miniaturized 10‐tube most‐probable‐number (MPN) enumeration protocol for E. sakazakii. This procedure is based on fluorogenic detection as a result of the growth and α‐glucosidase production from E. sakazakii in broth containing 4‐methylumbelliferyl‐α‐D‐glucoside (OK medium). The correlation between E. sakazakii counts by conventional plating and microtiter MPN methods was highly agreeable in 0.2% peptone water (R2 = 0.94) and reconstituted infant milk formula (R2 = 0.91). From these results, the new rapid method can quickly monitor E. sakazakii counts in infant milk formula with a high correlation with the conventional plating method. The results indicate that the microtiter MPN method required much shorter incubation times (<10 h) than the conventional plating method (<24 h) and provided a more economical way to monitor E. sakazakii, using selective and differential medium in end point determinations.
Arg16Gly polymorphism of the β2‐adrenergic receptor is associated with differences in cardiovascular function at rest and during exercise in humans
Authors: Snyder Eric M. , Beck Kenneth C. , Dietz Niki M. , Eisenach John H. , Joyner Michael J. , Turner Stephen T. , Johnson Bruce D.
Published: December 2005

In humans, subjects homozygous for arginine (ArgArg) at codon 16 of the β2‐adrenergic receptor (β2AR) have been shown to have greater agonist‐mediated desensitization than subjects homozygous for glycine (GlyGly). We sought to determine if this substitution differentially influenced cardiovascular function during short duration (9 min) low and high intensity exercise (40 and 75% of peak work). Healthy Caucasian ArgArg (n= 16), GlyGly (n= 31) and ArgGly (n= 17) subjects matched for age, sex and peak oxygen uptake were studied. There were no differences in adrenaline (ADR) at rest or with heavy exercise, but the ArgArg group had lower ADR with light exercise (P= 0.04). Resting heart rate (HR) was higher in ArgArg (P < 0.01), while cardiac output , stroke volume (SV), and mean arterial pressure (MAP) were lower than the other groups for ArgArg, ArgGly and GlyGly, respectively, means ±s.e.m., P < 0.01), however, no differences were observed in systemic vascular resistance (SVR). With low intensity exercise and high intensity exercise the ArgArg group continued to have a lower , SV and MAP compared to the other groups (P < 0.05), with no differences observed in SVR. During recovery, the ArgArg subjects continued to have a lower MAP but there were no differences in HR, , or SVR. These data suggest that subjects homozygous for Arg at codon 16 of the β2AR have reduced and MAP at rest that persist during exercise with no evidence for differential changes over the course of exercise despite large changes in catecholamines. This may suggest possible genotype‐related differences in baseline receptor function or density which causes phenotypic differences at rest that are sustained during short‐term exercise.
Functional effects of naturally occurring KCNJ11 mutations causing neonatal diabetes on cloned cardiac KATP channels
Authors: Tammaro Paolo , Proks Peter , Ashcroft Frances M.
Published: December 2005

ATP‐sensitive K+ (KATP) channels are hetero‐octamers of inwardly rectifying K+ channel (Kir6.2) and sulphonylurea receptor subunits (SUR1 in pancreatic β‐cells, SUR2A in heart). Heterozygous gain‐of‐function mutations in Kir6.2 cause neonatal diabetes, which may be accompanied by epilepsy and developmental delay. However, despite the importance of KATP channels in the heart, patients have no obvious cardiac problems. We examined the effects of adenine nucleotides on KATP channels containing wild‐type or mutant (Q52R, R201H) Kir6.2 plus either SUR1 or SUR2A. In the absence of Mg2+, both mutations reduced ATP inhibition of SUR1‐ and SUR2A‐containing channels to similar extents, but when Mg2+ was present ATP blocked mutant channels containing SUR1 much less than SUR2A channels. Mg‐nucleotide activation of SUR1, but not SUR2A, channels was markedly increased by the R201H mutation. Both mutations also increased resting whole‐cell KATP currents through heterozygous SUR1‐containing channels to a greater extent than for heterozygous SUR2A‐containing channels. The greater ATP inhibition of mutant Kir6.2/SUR2A than of Kir6.2/SUR1 can explain why gain‐of‐function Kir6.2 mutations manifest effects in brain and β‐cells but not in the heart.
Cell proliferation depends on mitochondrial Ca2+ uptake: inhibition by salicylate
Authors: Núñez Lucía , Valero Ruth A. , Senovilla Laura , Sanz‐Blasco Sara , García‐Sancho Javier , Villalobos Carlos
Published: December 2005

Store‐operated Ca2+ entry (SOCE) is a ubiquitous Ca2+ influx pathway involved in control of multiple cellular and physiological processes including cell proliferation. Recent evidence has shown that SOCE depends critically on mitochondrial sinking of entering Ca2+ to avoid Ca2+‐dependent inactivation. Thus, a role of mitochondria in control of cell proliferation could be anticipated. We show here that activation of SOCE induces cytosolic high [Ca2+] domains that are large enough to be sensed and avidly taken up by a pool of nearby mitochondria. Prevention of mitochondrial clearance of the entering Ca2+ inhibited both SOCE and cell proliferation in several cell types including Jurkat and human colon cancer cells. In addition, we find that therapeutic concentrations of salicylate, the major metabolite of aspirin, depolarize partially mitochondria and inhibit mitochondrial Ca2+ uptake, as revealed by mitochondrial Ca2+ measurements with targeted aequorins. This salicylate‐induced inhibition of mitochondrial Ca2+ sinking prevented SOCE and impaired cell growth of Jurkat and human colon cancer cells. Finally, direct blockade of SOCE by the pyrazole derivative BTP‐2 was sufficient to arrest cell growth. Taken together, our results reveal that cell proliferation depends critically on mitochondrial Ca2+ uptake and suggest that inhibition of tumour cell proliferation by salicylate may be due to interference with mitochondrial Ca2+ uptake, which is essential for sustaining SOCE. This novel mechanism may contribute to explaining the reported anti‐proliferative and anti‐tumoral actions of aspirin and dietary salicylates.
Mean and covariance of the forward field propagated through a stratified ocean waveguide with three-dimensional random inhomogeneities
Authors: Ratilal Purnima , Makris Nicholas C.
Published: December 2005

Compact analytic expressions are derived for the mean, mutual intensity, and spatial covariance of the acoustic field forward propagated though a stratified ocean waveguide containing three-dimensional random surface and volume inhomogeneities. The inhomogeneities need not obey a stationary random process in space, can be of arbitrary composition and size relative to the wavelength, or can have large surface roughness and slope. The form of the mean forward field after multiple scattering through the random waveguide is similar to that of the incident field, except for a complex change in the horizontal wave number of each mode. This change describes attenuation and dispersion induced by the medium’s inhomogeneities, including potential mode coupling along the propagation path. The spatial covariance of the forward field between two receivers includes the accumulated effects of both coherent and incoherent multiple forward scattering through the random waveguide. It is expressed as a sum of modal covariance terms. Each term depends on the medium’s expected modal extinction densities as well as the covariance of its scattering properties, which potentially couple each mode to every other mode. Three-dimensional scattering effects can become important at ranges where the Fresnel width exceeds the cross-range coherence scale of the medium’s inhomogeneities.
Mean and variance of the forward field propagated through three-dimensional random internal waves in a continental-shelf waveguide
Authors: Chen Tianrun , Ratilal Purnima , Makris Nicholas C.
Published: December 2005

The mean and variance of the acoustic field forward propagated through a stratified ocean waveguide containing three-dimensional (3-D) random internal waves is modeled using an analytic normal mode formulation. The formulation accounts for the accumulated effects of multiple forward scattering. These lead to redistribution of both coherent and incoherent modal energies, including attenuation and dispersion. The inhomogeneous medium’s scatter function density is modeled using the Rayleigh-Born approximation to Green’s theorem to account for random fluctuations in both density and compressibility caused by internal waves. The generalized waveguide extinction theorem is applied to determine attenuation due to scattering from internal wave inhomogeneities. Simulations for typical continental-shelf environments show that when internal wave height exceeds the acoustic wavelength, the acoustic field becomes so randomized that the expected total intensity is dominated by the field variance beyond moderate ranges. This leads to an effectively saturated field that decays monotonically and no longer exhibits the periodic range-dependent modal interference structure present in nonrandom waveguides. Three-dimensional scattering effects can become important when the Fresnel width approaches and exceeds the cross-range coherence length of the internal wave field. Density fluctuations caused by internal waves are found to noticably affect acoustic transmission in certain Arctic environments.
Patch near-field acoustical holography in cylindrical geometry
Authors: Lee Moohyung , Bolton J. Stuart
Published: December 2005

Spatial discrete Fourier transform-based near-field acoustical holography is known to suffer from windowing effects since the measurement aperture is necessarily finite. The latter effect can be mitigated by using patch holography, in which the measured field is extended beyond the measurement aperture based on successive smoothing operations. In this article, the application of a patch holography algorithm to cylindrical geometries is described. In planar geometry, initial zero-padding can be applied to the hologram pressure to an arbitrary degree in both in-plane directions since the pressure magnitude is expected to limit ultimately towards zero in both directions. In a cylindrical geometry, zero-padding can be implemented axially in the same way, but the number of zeros added in the circumferential direction is necessarily determined by the angular sample spacing owing to the periodic nature of the field in this direction. By using both numerical simulation and experimental results, it is shown that the patch extrapolation procedure works well in the cylindrical case, and a discussion of rigid reflecting boundaries is also included. Finally, reconstruction results obtained by the combined use of pressures measured in the finite aperture and two different regularization parameter selection techniques are compared, and the effect of projection distance is discussed.
Evidence for a bipolar change in distortion product otoacoustic emissions during contralateral acoustic stimulation in humans
Authors: Müller Jörg , Janssen Thomas , Heppelmann Guido , Wagner Wolfgang
Published: December 2005

The aim of this study was to investigate the activity of the medial olivocochlear (MOC) efferents during contralateral (CAS) and ipsilateral acoustic stimulation (IAS) by recording distortion product otoacoustic emission (DPOAE) suppression and DPOAE adaptation in humans. The main question was: do large bipolar changes in DPOAE level (transition from enhancement to suppression) also occur in humans when changing the primary tone level within a small range as described by Maison and Liberman for guinea pigs [J. Neurosci. 20, 4701–4707 (2000)]? In the present study, large bipolar changes in DPOAE level (14dB on average across subjects) were found during CAS predominantly at frequencies where dips in the DPOAE fine structure occurred. Thus, effects of the second DPOAE source might be responsible for the observed bipolar effect. In contrast, comparable effects were not found during IAS as was reported in guinea pigs. Reproducibility of CAS DPOAEs was better than that for IAS DPOAEs. Thus, contralateral DPOAE suppression is suggested to be superior to ipsilateral DPOAE adaptation with regard to measuring the MOC reflex strength and for evaluating the vulnerability of the cochlea to acoustic overexposure in a clinical context.
The advantage of knowing where to listen
Authors: Kidd Gerald , Arbogast Tanya L. , Mason Christine R. , Gallun Frederick J.
Published: December 2005

This study examined the role of focused attention along the spatial (azimuthal) dimension in a highly uncertain multitalker listening situation. The task of the listener was to identify key words from a target talker in the presence of two other talkers simultaneously uttering similar sentences. When the listener had no a priori knowledge about target location, or which of the three sentences was the target sentence, performance was relatively poor—near the value expected simply from choosing to focus attention on only one of the three locations. When the target sentence was cued before the trial, but location was uncertain, performance improved significantly relative to the uncued case. When spatial location information was provided before the trial, performance improved significantly for both cued and uncued conditions. If the location of the target was certain, proportion correct identification performance was higher than 0.9 independent of whether the target was cued beforehand. In contrast to studies in which known versus unknown spatial locations were compared for relatively simple stimuli and tasks, the results of the current experiments suggest that the focus of attention along the spatial dimension can play a very significant role in solving the “cocktail party” problem.
Analysis of the near-field ultrasonic scattering at a surface crack
Authors: Masserey Bernard , Mazza Edoardo
Published: December 2005

The near-field scattering of a Rayleigh wave at a surface crack is analyzed with analytical and numerical calculations complemented by detailed experimental observations. These investigations are directed towards the development of inversion schemes for surface crack sizing in mechanical components. The near-field analysis is based on a procedure that allows filtering the Rayleigh wave from the other wave modes scattered at the defect. Pointwise measurements of the out-of-plane displacement using a laser interferometer lead to a complete displacement field image in the crack near field with high spatial resolution. The numerical calculations are compared with the analytical solution and the experimental data in order to validate specific crack modeling approaches and to identify parameters for surface crack characterization. The evaluation is carried out with respect to the stress fields at the crack tip, the surface displacement near field, Rayleigh wave transmission and reflection coefficients, and the time delay of Rayleigh wave transmission. The latter appears as the most suitable parameter for crack characterization due to the relative insensitivity of the measured values on the variability of the experimental conditions. The results of the present work also highlight differences between the scatterings at cracks and narrow slots (“artificial cracks”).
Synergistic modes of vocal tract articulation for American English vowels
Authors: Story Brad H.
Published: December 2005

The purpose of this study was to investigate the spatial similarity of vocal tract shaping patterns across speakers and the similarity of their acoustic effects. Vocal tract area functions for 11 American English vowels were obtained from six speakers, three female and three male, using magnetic resonance imaging (MRI). Each speaker’s set of area functions was then decomposed into mean area vectors and representative modes (eigenvectors) using principal components analysis (PCA). Three modes accounted for more than 90% of the variance in the original data sets for each speaker. The general shapes of the first two modes were found to be highly correlated across all six speakers. To demonstrate the acoustic effects of each mode, both in isolation and combined, a mapping between the mode scaling coefficients and [F1, F2] pairs was generated for each speaker. The mappings were unique for all six speakers in terms of the exact shape of the [F1, F2] vowel space, but the general effect of the modes was the same in each case. The results support the idea that the modes provide a common system for perturbing a unique underlying neutral vocal tract shape.
Interference from audio distracters during speechreading
Authors: Brungart Douglas S. , Simpson Brian D.
Published: December 2005

Although many audio-visual speech experiments have focused on situations where the presence of an incongruent visual speech signal influences the perceived utterance heard by an observer, there are also documented examples of a related effect in which the presence of an incongruent audio speech signal influences the perceived utterance seen by an observer. This study examined the effects that different distracting audio signals had on performance in a color and number keyword speechreading task. When the distracting sound was noise, time-reversed speech, or continuous speech, it had no effect on speechreading. However, when the distracting audio signal consisted of speech that started at the same time as the visual stimulus, speechreading performance was substantially degraded. This degradation did not depend on the semantic similarity between the target and masker speech, but it was substantially reduced when the onset of the audio speech was shifted relative to that of the visual stimulus. Overall, these results suggest that visual speech perception is impaired by the presence of a simultaneous mismatched audio speech signal, but that other types of audio distracters have little effect on speechreading performance.
An improved acoustic microimaging technique with learning overcomplete representation
Authors: Zhang Guang-Ming , Harvey David M. , Braden Derek R.
Published: December 2005

Advancements in integrated circuit (IC) package technology are increasingly leading to size shrinkage of modern microelectronic packages. This size reduction presents a challenge for the detection and location of the internal features/defects in the packages, which have approached the resolution limit of conventional acoustic microimaging, an important nondestructive inspection technique in the semiconductor industry. In this paper, to meet the challenge the learning overcomplete representation technique is pursued to decompose an ultrasonic A-scan signal into overcomplete representations over a learned overcomplete dictionary. Ultrasonic echo separation and reflectivity function estimation are then performed by exploiting the sparse representability of ultrasonic pulses. An improved acoustic microimaging technique is proposed by integrating these operations into the conventional acoustic microimaging technique. Its performance is quantitatively evaluated by elaborated experiments on ultrasonic A-scan signals using acoustic microimaging (AMI) error criteria. Results obtained both from simulated and measured A-scans are presented to demonstrate the superior axial resolution and robustness of the proposed technique.
Herpesviral Protein Networks and Their Interaction with the Human Proteome
Authors: Uetz Peter , Dong Yu-An , Zeretzke Christine , Atzler Christine , Baiker Armin , Berger Bonnie , Rajagopala Seesandra V. , Roupelieva Maria , Rose Dietlind , Fossum Even , Haas Jürgen
Published: December 2005

The comprehensive yeast two-hybrid analysis of intraviral protein interactions in two members of the herpesvirus family, Kaposi sarcoma–associated herpesvirus (KSHV) and varicella-zoster virus (VZV), revealed 123 and 173 interactions, respectively. Viral protein interaction networks resemble single, highly coupled modules, whereas cellular networks are organized in separate functional submodules. Predicted and experimentally verified interactions between KSHV and human proteins were used to connect the viral interactome into a prototypical human interactome and to simulate infection. The analysis of the combined system showed that the viral network adopts cellular network features and that protein networks of herpesviruses and possibly other intracellular pathogens have distinguishing topologies.
Adipose tissue compensates for defect of phosphatidylinositol 3′-kinase induced in liver and muscle by dietary fish oil in fed rats
Authors: Corporeau Charlotte , Foll Christelle Le , Taouis Mohammed , Gouygou Jean-Paul , Bergé Jean-Pascal , Delarue Jacques
Published: December 2005

The present work aimed to study in rats whether substitution of a low level of fish oil (FO; 2.2% of calories) into a low-fat diet (6.6% of calories from fat as peanut-rape oil or control diet) 1) has a tissue-specific effect on insulin signaling pathway and 2) prevents dexamethasone-induced alteration of insulin signaling in liver, muscle, and adipose tissue. Sixteen rats were used for study of insulin signaling, and sixteen rats received an oral glucose load (3 g/kg). Eight rats/group consumed control diet or diet containing FO over 5 wk. Four rats from each group received a daily intraperitoneal injection of saline or dexamethasone (1 mg·kg−1·day−1) for the last 5 days of feeding. In liver, FO decreased phosphatidylinositol 3′-kinase (PI 3′-kinase) activity by 54% compared with control diet. A similar result was obtained in muscle. In both liver and muscle, FO clearly amplified the effect of dexamethasone. FO did not alter early steps of insulin signaling, and in muscle GLUT4 protein content remained unaltered. In adipose tissue, FO increased PI 3′-kinase activity by 74%, whereas dexamethasone decreased it by 65%; inhibition of PI 3′-kinase activity by dexamethasone was similar in rats fed FO or control diet, and GLUT4 protein content was increased by 61% by FO. Glycemic and insulinemic responses to oral glucose were not modified by FO. In conclusion, FO increased PI 3′-kinase activity in adipose tissue while inhibiting it in liver and muscle. The maintenance of whole body glucose homeostasis suggests an important role of adipose tissue for control of glucose homeostasis.
Aging attenuates both the regularity and joint synchrony of LH and testosterone secretion in normal men: analyses via a model of graded GnRH receptor blockade
Authors: Liu Peter Y. , Pincus Steven M. , Takahashi Paul Y. , Roebuck Pamela D. , Iranmanesh Ali , Keenan Daniel M. , Veldhuis Johannes D.
Published: December 2005

Testosterone (T) secretion declines in the aging male, albeit for unknown reasons. From an ensemble perspective, repeated incremental signaling among gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), and T is required to maintain physiological androgen availability. Pattern-regularity statistics, such as univariate approximate entropy (ApEn) and bivariate cross-ApEn, provide specific and sensitive model-free measurement of altered multipathway control. The present study exploits partial muting of one pathway (GnRH drive) to appraise adaptive regulation of LH and T secretion in young and aging individuals. Analyses comprised 100 paired 18-h LH and T concentration time series obtained in 25 healthy men ages 20–72 yr each administered placebo and three graded doses of a specific GnRH-receptor antagonist. Graded blockade of GnRH drive increased the individual regularity of LH and T secretion and the synchrony of LH-T feedforward and T-LH feedback in the cohort as a whole ( P < 0.001 for each). However, age markedly attenuated ganirelix-induced enhancement of univariate T orderliness and bivariate LH-T feedback and T-LH feedback synchrony ( P ≤ 0.0025). In summary, the present analyses support the thesis that aging disrupts coordinate control of T secretion, LH-T feedforward, and T-LH feedback in healthy men. Thus the experimental strategy of stepwise silencing of an agonistic pathway may have utility in dissecting the bases of altered neurohormonal linkages in other systems.
Zymogen activation in a reconstituted pancreatic acinar cell system
Authors: Thrower Edwin C. , Diaz de Villalvilla Alexander P. E. , Kolodecik Thomas R. , Gorelick Fred S.
Published: December 2005

Pathological activation of digestive zymogens within the pancreatic acinar cell initiates acute pancreatitis. Cytosolic events regulate this activation within intracellular compartments of unclear identity. In an in vivo model of acute pancreatitis, zymogen activation was detected in both zymogen granule-enriched and microsomal cellular fractions. To examine the mechanism of this activation in vitro, a reconstituted system was developed using pancreatic cytosol, a zymogen granule-enriched fraction, and a microsomal fraction. Addition of cytosol to either particulate fraction resulted in a prominent increase in both trypsin and chymotrypsin activities. The percentage of the pool of trypsinogen and chymotrypsinogen activated was about twofold and sixfold greater, respectively, in the microsomal than in the zymogen granule-enriched fraction. Activation of chymotrypsinogen but not trypsinogen was significantly enhanced by ATP (5 mM) but not by the inactive ATP analog AMP-PNP. The processing of procarboxypeptidase B to its mature form also demonstrated a requirement for ATP and cytosol. E64d, an inhibitor of cathepsin B, a thiol protease that can activate trypsin, completely inhibited trypsin activity but did not affect chymotrypsin activity or carboxypeptidase B generation. These studies demonstrate that both zymogen granule-enriched and microsomal fractions from the pancreas can support cytosol-dependent zymogen activation. A component of the activation of some zymogens, such as chymotrypsinogen and procarboxypeptidase, may depend on ATP but not on trypsin or cathepsin B.
Synergistic targeting with bone marrow-derived cells and PDGF improves diabetic vascular function
Authors: Klibansky David A. , Chin Andrew , Duignan Inga J. , Edelberg Jay M.
Published: December 2005

Diabetes mellitus is associated with an increased risk of vascular disease, with significant alterations in systemic endothelial progenitor cells (EPCs) and peripheral vascular function. To identify the contribution of the different vascular compartments in the diabetic impairment of vascularization, we employed streptozotocin- and control-treated 3-mo-old C57Bl/6 mice in an isogeneic pinnal cardiac allograft model, revealing a significant delay in vascularization of wild-type cardiac tissue transplanted into diabetic mice. To investigate the basis of this impairment, the function of diabetic bone marrow cells was tested by transplantation of bone marrow cells isolated from diabetic and control mice into intact, unirradiated 18-mo-old C57Bl/6 mice, which have impaired function of both EPCs and peripheral endothelial cells. Importantly, cells derived from control, but not diabetic, bone marrow integrated into transplanted cardiac allografts. To assess the contribution of diabetic changes in the local vasculature, diabetic mice were treated with pinnal injections of platelet-derived growth factor (PDGF)-AB, which promotes cardiac angiogenesis in wild-type mice. However, whereas PDGF-AB enhanced allograft function in control mice, the activity of the cardiac transplants in the PDGF-AB-treated diabetic mice was significantly decreased. To decipher the potential interactions between systemic bone marrow-derived cells and local vascular pathways, diabetic mice were transplanted with wild-type bone marrow cells with or without PDGF-AB pinnal pretreatment, resulting in improved allograft function and donor cell recruitment only in the combination treatment arm. Overall, these studies show that the diabetic impairment in cardiac angiogenesis can be reversed by targeting the synergism between local trophic pathways and systemic cell function.
Thromboxane A2-induced arrhythmias in the anesthetized rabbit
Authors: Wacker Michael J. , Best Shaun R. , Kosloski Lisa M. , Stachura Christopher J. , Smoot Rory L. , Porter Charles B. , Orr James A.
Published: December 2005

Experiments were conducted in the anesthetized rabbit to investigate mechanisms for arrhythmias that occur after left atrial injection of the thromboxane A2 (TxA2) mimetic U-46619. Arrhythmias were primarily of ventricular origin, dose dependent in frequency, and TxA2 receptor mediated. The response was receptor specific since arrhythmias were absent after pretreatment with a specific TxA2 receptor antagonist (SQ-29548) and did not occur in response to another prostaglandin, PGF2α. Alterations in coronary blood flow were unlikely the cause of these arrhythmias because coronary blood flow (as measured with florescent microspheres) was unchanged after U-46619, and there were no observable changes in the ECG-ST segment. In addition, arrhythmias did not occur after administration of another vasoconstrictor (phenylephrine). The potential involvement of autonomic cardiac efferent nerves in these arrhythmias was also investigated because TxA2 has been shown to stimulate peripheral nerves. Pretreatment of animals with the β-adrenergic receptor antagonist propranolol did not reduce the frequency of these arrhythmias. Pretreatment with atropine or bilateral vagotomy resulted in an increased frequency of arrhythmias, suggesting that parasympathetic nerves may actually inhibit the arrhythmogenic activity of TxA2. These experiments demonstrate that left atrial injection of U-46619 elicits arrhythmias via a mechanism independent of a significant reduction in coronary blood flow or activation of the autonomic nervous system. It is possible that TxA2 may have a direct effect on the electrical activity of the heart in vivo, which provides significant implications for cardiac events where TxA2 is increased, e.g., after myocardial ischemia or administration of cyclooxygenase-2 inhibitors.
Modulation of single-nephron GFR in the db/db mouse model of type 2 diabetes mellitus
Authors: Levine David Z. , Iacovitti Michelle , Robertson Susan J. , Mokhtar Ghadeer A.
Published: December 2005

Hyperfiltration has been implicated in the progression toward diabetic nephropathy in type 2 diabetes mellitus (DM2). This study focuses for the first time on the in vivo modulation of single-nephron GFR (SNGFR) in the classic B6.Cg-m+/+Leprdb/J (db/db) mouse model of DM2. To obtain stable preparations, it was necessary to use a sustaining infusion of 3.3 ml·100 g body wt−1·h−1, or higher. SNGFR (measured both proximally and distally) was greater in db/db vs. heterozygote (db/m) mice ( P < 0.05) but not vs. the wild-type (WT) mice. The tubuloglomerular feedback (TGF) responses, determined as free-flow proximal vs. distal SNGFR differences, were significant in db/db mice (11.6 ± 0.8 vs. 9.3 ± 1.0 nl/min, P < 0.01), in db/m mice (8.0 ± 0.8 vs. 7.2 ± 0.6 nl/min, P < 0.02), and WT mice (9.9 ± 0.6 vs. 8.9 ± 0.7 nl/min, P < 0.05). After increasing the sustaining infusion in the db/db mice, to offset glycosuric urine losses, the SNGFR increased significantly, and the TGF response was abolished. In these volume-replete db/db mice, absolute fluid reabsorption measured both at the late proximal and distal tubular sites were significantly increased vs. db/m mice infused at 3.3 ml·100 g body wt−1·h−1. After infusion of the neuronal nitric oxide synthase (nNOS) inhibitor S-methylthiocitrulline, SNGFR fell in both db/db and db/m mice. These studies show that SNGFR is elevated in this mouse model of DM2, is suppressed by nNOS inhibition, and is modulated by TGF influences that are altered by the diabetic state and responsive to changes in extracellular fluid volume.