bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of sensory impairment on social interaction between residents in care homes
Authors: Cook Glenda , Brown‐Wilson Christine , Forte Denise
Published: November 2006

Aim.  The aim was to draw on older people's narratives to illuminate the experience of living in a care home and the impact that vision and hearing impairments have on the individual's ability to engage in social interactions with other residents.

Methods.  The paper draws on two research studies, first, a hermeneutic inquiry examining the meaning ascribed to living in a care home, the second, a constructivist study, exploring relationships between residents, families and staff. Both studies drew on older people's narrative accounts to explore their experiences of living in a care home. On independently interpreting the narratives a similar theme emerged around the challenges to social interactions experienced by residents with sight and/or hearing impairment. This resulted in a cross study analysis to further illuminate this theme.

Findings.  The cross study analysis highlighted the difficulties residents experience in interacting with others, in the home, as a consequence of sight and/or hearing impairment, and the potential impact this had on feelings of social isolation. This is illustrated through narratives from two residents, one with sight impairment and the other with hearing loss. The narratives highlight the problems these people encountered and how resilient they were in adjusting to their sensory loss and maintaining social interactions. One conclusion from the study is the need for more empirical work in this area.

Relevance to clinical practice.  The paper identifies a number of issues for practice including staff taking a more proactive role in screening for, and managing, visual and hearing impairments in residents. Also the vital role staff play in ensuring the environment optimizes the residents’ ability to fully engage in the residential community.
The fig wax scale Ceroplastes rusci (Linnaeus) (Homoptera: Coccidae) in south‐east Vietnam: Pest status, life history and biocontrol trials with Eublemma amabilis Moore (Lepidoptera: Noctuidae)
Authors: VU Nga Thi , EASTWOOD Rod , NGUYEN Chat Thi , PHAM Lam Van
Published: November 2006

The fig wax scale Ceroplastes rusci (Linnaeus) is a serious pest of fruit trees in many countries. In the present study we investigated the extent of C. rusci infestation and the range of host species, particularly in fruit orchards, in south‐east Vietnam. Captive populations of C. rusci were established to record life history parameters and to investigate the efficacy of an endemic predacious moth, Eublemma amabilis Moore, as a potential biocontrol agent. Heavy infestation of C. rusci (up to 100%) was recorded in soursop and other fruit orchards, and the culturally important Hoa Mai flower was also affected. Captive breeding trials found E. amabilis to be an efficient predator of C. rusci, but an unusual hyperactive trait in early instars of E. amabilis resulted in lower than expected survival rates. The implications of this trait in terms of the laboratory environment, augmentative release protocols and as a survival strategy are discussed.
Ecological and morphological characteristics of the endoparasitoids of larval Acronicta rumicis (Lepidoptera: Noctuidae)
Authors: CHO Youngho , KWON Ohseok , NAM Sang‐Ho
Published: November 2006

The Hymenopterans Glyptapanteles liparidis, Microplitis sp. and Diadegma sp. were found to be larval parasitoids and koinobionts of Acronicta rumicis (Lepidoptera: Noctuidae). Mesochorus semirufus is believed to be a new unreported hyperparasitoid of G. liparidis, which, along with M. semirufus, is a gregarious parasitoid. In contrast, the parasitoids Microplitis sp. and Diadegma sp. are solitary. All of the hymenopteran parasitoids are multivoltine insects that emerge from A. rumicis more than once. Compcilura concinnata, Euexorista sp. and Exorista sp. of the Diptera were found to be larval–pupal parasitoids, solitary parasitoids and koinobionts. These three species are univoltine, and emerge only once from A. rumicis. Morphological and life cycle data were collected for G. liparidis, and for the parasitoids of that species found in this study. The major and minor axes of an egg of G. liparidis were 0.10 and 0.02 mm, respectively, while the mean clutch size of G. liparidis was 67.71 ± 39.36 individuals. The body length of female and male G. liparidis were 2.25 ± 0.06 and 2.21 ± 0.12 mm, respectively, and the longevity of an adult was 2.93 ± 0.96 days. Among the parasitoids, the mean body length of an adult Microplitis sp. was 3.5 mm and adults lived for an average of 8.13 ± 3.54 days. The adult Diadegma sp. was larger (mean body length 6.5 mm) but lived for a shorter interval (3.33 ± 1.32 days). The body lengths of female and male M. semirufus were 3.16 ± 0.11 and 3.10 ± 0.23 mm, respectively, greater than the body lengths of female and male G. liparidis. The body lengths of adult C. concinnata, Euexorista sp. and Exorista sp. were 9.5, 9.53 and 8.68 mm, respectively. All of their pupae were dark brown.
CD45 Isoform Expression in Microglia and Inflammatory Cells in HIV‐1 Encephalitis
Authors: Cosenza‐Nashat Melissa A. , Kim Mee‐Ohk , Zhao Meng‐Liang , Suh Hyeon‐Sook , Lee Sunhee C.
Published: November 2006

CD45 is a membrane tyrosine phosphatase that modulates the function of the hematopoietic cells.In vitro, agonist antibodies to CD45RO or CD45RB isoforms have been shown to suppress microglial activation, but whether microgliain vivoexpress these isoforms in HIV encephalitis (HIVE) is unknown. Brain sections from control and HIVE were immunostained for CD45 isoforms using exon‐specific antibodies (RA, RB, RC and RO). RA and RC were limited to rare lymphocytes, while RB expression was robust in microglia and inflammatory cells. RO was low in control microglia, but increased in HIVE. RO was also localized to macrophages and CD8+ T cells. Targeting CD45in vivowith isoform‐specific antibodies remains a therapeutic option for neuroinflammatory diseases.
Influence of Transglutaminase‐Induced Cross‐Linking on Properties of Fish Gelatin Films
Authors: Yi J. B. , Kim Y. T. , Bae H. J. , Whiteside W. S. , Park H. J.
Published: November 2006

ABSTRACT:  Fish gelatin (FG) is a potential alternative to current mammalian (beef and pork) gelatin. However, its physical and thermal properties limit its use in many applications. The treatment of microbial transglutaminase (MTGase) on FG could be a practical way to increase the use of FG films in various applications. Physical properties, barrier properties, and molecular weight change of FG films were measured. The viscosity of the MTGase‐treated FG solution significantly (P < 0.05) increased from 6.81 ± 0.65 cP to 35.04 ± 3.59 cP as the reaction time and concentration of MTGase increased. After employing 2% of MTGase into FG solution, the tensile strength increased from 48.03 ± 5.45 MPa to 68.00 ± 1.9 MPa, while percent elongation decreased from 13.1%± 2.90% to 1.47%± 0.05%. Oxygen barrier property was significantly (P < 0.05) increased from 7.24 ± 1.48 cc·m/m2·d to 17.69 ± 3.08 cc·m/m2·d, while water vapor permeability was not statistically (P < 0.05) different. The melting temperature (Tm) measured by differential scanning calorimetry increased from 124.78 ± 1.98 °C to 158.49 ± 2.68 °C as the enzyme reaction time increased. The color values of L*, a*, and b* were changed from 95.56 ± 0.09 to 95.50 ± 0.06, from −0.17 ± 0.01 to −0.23 ± 0.00, and from 3.17 ± 0.04 to 3.47 ± 0.09, respectively. The opacity significantly (P < 0.05) increased from 1.43%± 0.32% to 2.87%± 0.06%. SDS‐PAGE results showed that the molecular weight of fish gelatin films increased when the MTGase reaction takes place.
A Structural Integrity Assessment Methodology for Pressurized Vessels
Authors: Yee Raymond K. , Kapper Mike
Published: November 2006

Pressurized vessels such as a steam drum in a typical power plant can often experience in-service cracking. Structural integrity assessment methodology can be a useful tool to determine the suitability of a vessel for service. This methodology may include fitness-for-service and remaining useful life analyses of a vessel based on the nondestructive examination (NDE) results and operating conditions. In this paper, the structural integrity assessment methodology applied to a steam drum case study is described. The analysis procedure, material property determination, stress analysis, limiting flaw size evaluation, and remaining useful life evaluation for the drum are discussed. A thermal shock design tool is briefly introduced. Recommendations for appropriate action are also presented. The assessment methodology employed in this paper can be applied to other similar pressurized vessels and structures in power plants.
Effect of Thread Pitch and Initial Tension on the Self-Loosening of Threaded Fasteners
Authors: Nassar Sayed A. , Housari Basil A.
Published: November 2006

A mathematical model and an experimental procedure are presented to study the self-loosening phenomenon of threaded fasteners that are subjected to cyclic transverse loads. The study investigates the effect of thread pitch, initial bolt tension, and the amplitude of the external excitation on the loosening of a single-bolt joint. The rate of drop in the joint clamp load (fastener tension) per cycle, as well as the total number of cycles that would cause the complete loss of clamp load, are monitored. In the mathematical model, the differential equations of linear and angular motion of the bolt are formulated in terms of the system properties and the external cyclic transverse excitation. Numerical integration of the equation of angular motion provides the bolt rotation in the loosening direction, which causes the partial or full loss of the clamp load. An iterative MATLAB code is developed and used for the calculation of tension loss in the fastener tension due to the self-loosening. Analytical and experimental results are discussed.
Thermoelastic Stresses in Thick-Walled Vessels Under Thermal Transients via the Inverse Route
Authors: Segall A. E.
Published: November 2006

A common threat to thick-walled vessels and pipes is thermal shock from operational steady state or transient thermoelastic stresses. As such, boundary conditions must be known or determined in order to reveal the underlying thermal state. For direct problems where all boundary conditions (temperature or flux) are known, the procedure is relatively straightforward and mathematically tractable as shown by many studies. Although more practical from a measurement standpoint, the inverse problem where the boundary conditions must be determined from remotely determined temperature and/or flux data is ill-posed and inherently sensitive to errors in the data. As a result, the inverse route is rarely used to determine thermal stresses. Moreover, most analytical solutions to the inverse problem rely on a host of assumptions that usually restrict their utility to time frames before the thermal wave reaches the natural boundaries of the structure. To help offset these limitations and at the same time solve for the useful case of a thick-walled cylinder exposed to thermal loading on the internal surface, the inverse problem was solved using a least-squares determination of polynomial coefficients based on a generalized direct solution to the heat equation. Once the inverse problem was solved in this fashion and the unknown boundary condition on the internal surface determined, the resulting polynomial was used with the generalized direct solution to determine the internal temperature and stress distributions as a function of time and radial position. For a thick-walled cylinder under an internal transient with external convection, excellent agreement was seen with known temperature histories. Given the versatility of the polynomial solutions advocated, the method appears well suited for many thermal scenarios provided the analysis is restricted to the time interval used to determine the polynomial and the thermophysical properties that do not vary with temperature.
Mean Shear Stress Effect for a Notch-Free Ductile Material Under Pure Cyclic Torsional Loads
Authors: Wang Shyh-Jen
Published: November 2006

The relationship of torque versus angle of rotation stabilizes after only a few cycles so that the alternating stress will become a constant as long as the maximum shear stress is less than the shear yield strength of the material. Using this information in Findley‘s fatigue criterion, it is demonstrated that the mean shear stress has very little influence on the fatigue limit of a notch-free ductile material under cyclic torsional loading.
Improved volume-averaged model for steady and pulsed-power electronegative discharges
Authors: Kim Sungjin , Lieberman M. A. , Lichtenberg A. J. , Gudmundsson J. T.
Published: November 2006

An improved volume-averaged global model is developed for a cylindrical (radius R, length L) electronegative (EN) plasma that is applicable over a wide range of electron densities, electronegativities, and pressures. It is applied to steady and pulsed-power oxygen discharges. The model incorporates effective volume and surface loss factors for positive ions, negative ions, and electrons combining three electronegative discharge regimes: a two-region regime with a parabolic EN core surrounded by an electropositive edge, a one-region parabolic EN plasma, and a one-region flat-topped EN plasma, spanning the plasma parameters and gas pressures of interest for low pressure processing (below a few hundred millitorr). Pressure-dependent effective volume and surface loss factors are also used for the neutral species. A set of reaction rate coefficients, updated from previous model calculations, is developed for oxygen for the species O2, O2(Δg1), O, O2+, O+, and O−, based on the latest published cross-section sets and measurements. The model solutions yield all of the quantities above together with such important processing quantities such as the neutral/ion flux ratio ΓO∕Γi, with the discharge aspect ratio 2R∕L and pulsed-power period and duty ratio (pulse on-time/pulse period) as parameters. The steady discharge results are compared to an experiment, giving good agreement. For steady discharges, increasing 2R∕L from 1 to 6 leads to a factor of 0.45 reduction in ΓO∕Γi. For pulsed discharges with a fixed duty ratio, ΓO∕Γi is found to have a minimum with respect to pulse period. A 25% duty ratio pulse reduces ΓO∕Γi by a factor of 0.75 compared to the steady-state case.
Si
O
2
-like film deposition by dielectric barrier discharge plasma gun at ambient temperature under an atmospheric pressure
Authors: Chen Qiang , Zhang Yuefei , Han Erli , Ge Yuanjing
Published: November 2006

A medium-frequency dielectric barrier discharge (DBD) plasma gun was used to deposit SiO2-like films at ambient temperature under atmospheric pressure. SiO2-like films were deposited on Si and stainless-steel surfaces by flowing Ar gas containing hexamethyldisiloxane (HMDSO) monomer through the gun. The authors found that the chemical structure of the deposited SiO2-like film strongly depended on the HMDSO monomer ratio in the flowing gas and on the incident power. Fourier transform infrared spectroscopy showed no hydroxyl group in the chemical structure under the low HMDSO ratio in flowing gas or high incident plasma power. Scanning electron microscopy and atomic force microscopy revealed that SiO2-like films began to grow as islands and then formed in columns having porosity. Oxygen added to the plasma-gun flow plays a lesser role in the SiO2-like deposition from a DBD plasma gun at atmospheric pressure, and the critical temperature for pure SiO2 formation is also greatly lowered.
Measurement of desorbed products during organic polymer thin film etching by plasma beam irradiation
Authors: Kurihara Kazuaki , Karahashi Kazuhiro , Egami Akihiro , Nakamura Moritaka
Published: November 2006

The authors investigated the etching characteristics of three kinds of methacrylate polymer films, which have the same main chain but with different side chains, using a plasma beam irradiation apparatus. The polymers are polytbutylmethacrylate, polybenzylmethacrylate, and polycyclohexylmethacrylate. The major desorbed products during nitrogen plasma beam etching were found to be HCN and C2N2 for all methacrylate polymer films. The desorbed products originating from the polymer structure, namely, the main chain and the side chain, were hardly observed. The energy distributions of desorbed products were mainly composed of Maxwell-Boltzmann distribution with a small component of collision cascade distribution for all three polymers and were slightly dependent on the ion energy. It is concluded that chemical sputtering, which can be defined as the production of weakly bound species by ion bombardment, followed by thermal desorption, is the significant ion induced mechanism of organic polymer etching.
An audio-visual corpus for speech perception and automatic speech recognition
Authors: Cooke Martin , Barker Jon , Cunningham Stuart , Shao Xu
Published: November 2006

An audio-visual corpus has been collected to support the use of common material in speech perception and automatic speech recognition studies. The corpus consists of high-quality audio and video recordings of 1000 sentences spoken by each of 34 talkers. Sentences are simple, syntactically identical phrases such as “place green at B 4 now.” Intelligibility tests using the audio signals suggest that the material is easily identifiable in quiet and low levels of stationary noise. The annotated corpus is available on the web for research use.
A stochastic representation of environmental uncertainty and its coupling to acoustic wave propagation in ocean waveguides
Authors: Finette Steven
Published: November 2006

It is argued that a quantitative measure of incomplete environmental knowledge or information (i.e., environmental uncertainty) should be included in any simulation-based predictions linked to acoustic wave propagation. A method is then proposed to incorporate environmental uncertainty directly into the computation of acoustic wave propagation in ocean waveguides. In this regard, polynomial chaos expansions are chosen to represent uncertainty in both the environment and acoustic field. The sound-speed distribution and acoustic field are therefore generalized to stochastic processes, where uncertainty in the field is interpreted in terms of its statistical moments. Starting from the narrow angle parabolic approximation, a set of coupled differential equations is derived in which the coupling term links incomplete environmental information to the corresponding uncertainty in the acoustic field. Propagation of both the field and its uncertainty in an isospeed waveguide is considered as an example, where the sound speed is described by a random variable. The first two moments of the field are computed explicitly and compared to those obtained from independent Monte Carlo solution of the conventional (deterministic) parabolic equation that describes the acoustic wave properties.
Semi-automatic classification of bird vocalizations using spectral peak tracks
Authors: Chen Zhixin , Maher Robert C.
Published: November 2006

Automatic off-line classification and recognition of bird vocalizations has been a subject of interest to ornithologists and pattern detection researchers for many years. Several new applications, including bird vocalization classification for aircraft bird strike avoidance, will require real time classification in the presence of noise and other disturbances. The vocalizations of many common bird species can be represented using a sum-of-sinusoids model. An experiment using computer software to perform peak tracking of spectral analysis data demonstrates the usefulness of the sum-of-sinusoids model for rapid automatic recognition of isolated bird syllables. The technique derives a set of spectral features by time-variant analysis of the recorded bird vocalizations, then performs a calculation of the degree to which the derived parameters match a set of stored templates that were determined from a set of reference bird vocalizations. The results of this relatively simple technique are favorable for both clean and noisy recordings.
Continuous thermoacoustic mixture separation
Authors: Swift G. W. , Geller D. A.
Published: November 2006

The superposition of nonzero time-averaged mole flux Ṅ on a thermoacoustic wave in a binary gas mixture in a tube produces continuous mixture separation, in which one or more partially purified product streams are created from a feedstock stream. Significant product and feedstock flows occur through capillaries that are small enough to experience negligible thermoacoustic phenomena of their own. Experiments with a 50–50 helium-argon mixture show diverse consequences of nonzero flow, involving the addition of only one simple term nHṄ to the equation for the heavy component’s time-averaged mole flux, where nH is the mole fraction of the heavy component. A boundary condition for nH must be imposed on the equation wherever products flow out of the separation tube, but not where feedstock flows in.
Advantages of the Hilbert Huang transform for marine mammals signals analysis
Authors: Adam Olivier
Published: November 2006

While marine mammals emit variant signals (in time and frequency), the Fourier spectrogram appears to be the most widely used spectral estimator. In certain cases, this approach is suboptimal, particularly for odontocete click analysis and when the signal-to-noise ratio varies during the continuous recordings. We introduce the Hilbert Huang transform (HHT) as an efficient means for analysis of bioacoustical signals. To evaluate this method, we compare results obtained from three time-frequency representations: the Fourier spectrogram, the wavelet transform, and the Hilbert Huang transform. The results show that HHT is a viable alternative to the wavelet transform. The chosen examples illustrate certain advantages. (1) This method requires the calculation of the Hilbert transform; the time-frequency resolution is not restricted by the uncertainty principle; the frequency resolution is finer than with the Fourier spectrogram. (2) The original signal decomposition into successive modes is complete. If we were to multiply some of these modes, this would contribute to attenuate the presence of noise in the original signal and to being able to select pertinent information. (3) Frequency evolution for each mode can be analyzed as one-dimensional (1D) signal. We not need a complex 2D post-treatment as is usually required for feature extraction.
The experimental synthesis of random pressure fields: Methodology
Authors: Bravo Teresa , Maury Cédric
Published: November 2006

This paper presents a methodology for the off-line reproduction of random pressure fields with given spatial correlation characteristics. The simulation method is first presented, together with an outline of the signal processing techniques required. The design of an experimental setup is then detailed in relation with the nature of the simulated pressure fields. Of particular interest is the laboratory synthesis of three different types of partially correlated random excitations: an acoustic diffuse field, a grazing incident plane wave, and a turbulent boundary layer. The corresponding excitations are generated in a semianechoic chamber over a test panel using a near-field array of 16 loudspeakers driven by a set of optimal signals. The loudspeakers are positioned at a suitable distance above a sufficiently dense grid of microphones close to the simulation surface. The mutually correlated drive signals are determined from both the target correlation properties and the acoustic transfer functions measured between the loudspeakers and the microphones. This approach could provide a cost-effective method of reducing the variation of low frequency sound transmission measurements as well as simulating the propeller-induced noise and the boundary layer noise transmitted through aircraft fuselage structures.
Speech recognition in normal hearing and sensorineural hearing loss as a function of the number of spectral channels
Authors: Başkent Deniz
Published: November 2006

Speech recognition by normal-hearing listeners improves as a function of the number of spectral channels when tested with a noiseband vocoder simulating cochlear implant signal processing. Speech recognition by the best cochlear implant users, however, saturates around eight channels and does not improve when more electrodes are activated, presumably due to reduced frequency selectivity caused by channel interactions. Listeners with sensorineural hearing loss may also have reduced frequency selectivity due to cochlear damage and the resulting reduction in the nonlinear cochlear mechanisms. The present study investigates whether such a limitation in spectral information transmission would be observed with hearing-impaired listeners, similar to implant users. To test the hypothesis, hearing-impaired subjects were selected from a population of patients with moderate hearing loss of cochlear origin, where the frequency selectivity would be expected to be poorer compared to normal hearing. Hearing-impaired subjects were tested for vowel and consonant recognition in steady-state background noise of varying levels using a noiseband vocoder and as a function of the number of spectral channels. For comparison, normal-hearing subjects were tested with the same stimuli at different presentation levels. In quiet and low background noise, performance by normal-hearing and hearing-impaired subjects was similar. In higher background noise, performance by hearing-impaired subjects saturated around eight channels, while performance by normal-hearing subjects continued to increase up to 12–16 channels with vowels, and 10–12 channels with consonants. A similar trend was observed for most of the presentation levels at which the normal-hearing subjects were tested. Therefore, it is unlikely that the effects observed with hearing-impaired subjects were due to insufficient audibility or high presentation levels. Consequently, the results with hearing-impaired subjects were similar to previous results obtained with implant users, but only for background noise conditions.
Auditory measures of selective and divided attention in young and older adults using single-talker competition
Authors: Humes Larry E. , Lee Jae Hee , Coughlin Maureen P.
Published: November 2006

In this study, two experiments were conducted on auditory selective and divided attention in which the listening task involved the identification of words in sentences spoken by one talker while a second talker produced a very similar competing sentence. Ten young normal-hearing (YNH) and 13 elderly hearing-impaired (EHI) listeners participated in each experiment. The type of attention cue used was the main difference between experiments. Across both experiments, several consistent trends were observed. First, in eight of the nine divided-attention tasks across both experiments, the EHI subjects performed significantly worse than the YNH subjects. By comparison, significant differences in performance between age groups were only observed on three of the nine selective-attention tasks. Finally, there were consistent individual differences in performance across both experiments. Correlational analyses performed on the data from the 13 older adults suggested that the individual differences in performance were associated with individual differences in memory (digit span). Among the elderly, differences in age or differences in hearing loss did not contribute to the individual differences observed in either experiment.
M
-ary frequency shift keying communications over an underwater acoustic channel: Performance comparison of data with models
Authors: Yang Wen-Bin , Yang T. C.
Published: November 2006

The bit error rate (BER) is modeled for M-ary frequency-shift-keying (MFSK) signals in a fading channel using different envelope amplitude statistics and compared with frequency-hopping (FH) FSK signaling data collected during the TREX04 experiment, which used Binary FSK (BFSK) for each symbol. The BER data is found to be significantly higher than that of a Rayleigh fading channel and is found to agree with that modeled with a K-distribution amplitude fading distribution. Using the parameters of the K-distribution, independently measured from the M-sequence data collected in the same experiment, the modeled BER as a function of the signal-to-noise ratio (SNR) agrees well with the measured BER within the SNR of the data. This suggests that the BER of FH-FSK signaling can be predicted given some prior channel characterization measurements.
Generation of Gut-Homing IgA-Secreting B Cells by Intestinal Dendritic Cells
Authors: Mora J. Rodrigo , Iwata Makoto , Eksteen Bertus , Song Si-Young , Junt Tobias , Senman Balimkiz , Otipoby Kevin L. , Yokota Aya , Takeuchi Hajime , Ricciardi-Castagnoli Paola , Rajewsky Klaus , Adams David H. , von Andrian Ulrich H.
Published: November 2006

Normal intestinal mucosa contains abundant immunoglobulin A (IgA)–secreting cells, which are generated from B cells in gut-associated lymphoid tissues (GALT). We show that dendritic cells (DC) from GALT induce T cell–independent expression of IgA and gut-homing receptors on B cells. GALT-DC–derived retinoic acid (RA) alone conferred gut tropism but could not promote IgA secretion. However, RA potently synergized with GALT-DC–derived interleukin-6 (IL-6) or IL-5 to induce IgA secretion. Consequently, mice deficient in the RA precursor vitamin A lacked IgA-secreting cells in the small intestine. Thus, GALT-DC shape mucosal immunity by modulating B cell migration and effector activity through synergistically acting mediators.
A Member of the Second Carbohydrate Uptake Subfamily of ATP-Binding Cassette Transporters Is Responsible for Ribonucleoside Uptake inStreptococcus mutans
Authors: Webb Alexander J. , Hosie Arthur H. F.
Published: November 2006

Streptococcus mutanshas a significant number of transporters of the ATP-binding cassette (ABC) superfamily. Members of this superfamily are involved in the translocation of a diverse range of molecules across membranes. However, the functions of many of these members remain unknown. We have investigated the role of the singleS. mutansrepresentative of the second subfamily of carbohydrate uptake transporters (CUT2) of the ABC superfamily. The genetic context of genes encoding this transporter indicates that it may have a role in ribonucleoside scavenging. Inactivation ofrnsA(ATPase) orrnsB(solute binding protein) resulted in strains resistant to 5-fluorocytidine and 5-fluorouridine (toxic ribonucleoside analogues). As other ribonucleosides including cytidine, uridine, adenosine, 2-deoxyuridine, and 2-deoxycytidine protectedS. mutansfrom 5-fluorocytidine and 5-fluorouridine toxicity, it is likely that this transporter is involved in the uptake of these molecules. Indeed, thernsAandrnsBmutants were unable to transport [2-14C]cytidine or [2-14C]uridine and had significantly reduced [8-14C]adenosine uptake rates. Characterization of this transporter in wild-typeS. mutansindicates that it is a high-affinity (Km= 1 to 2 μM) transporter of cytidine, uridine, and adenosine. The inhibition of [14C]cytidine uptake by a range of structurally related molecules indicates that the CUT2 transporter is involved in the uptake of most ribonucleosides, including 2-deoxyribonucleosides, but not ribose or nucleobases. The characterization of this permease has directly shown for the first time that an ABC transporter is involved in the uptake of ribonucleosides and extends the range of substrates known to be transported by members of the ABC transporter superfamily.
Multiple GTPases Participate in the Assembly of the Large Ribosomal Subunit in
Bacillus subtilis
Authors: Schaefer Laura , Uicker William C. , Wicker-Planquart Catherine , Foucher Anne-Emmanuelle , Jault Jean-Michel , Britton Robert A.
Published: November 2006

GTPases have been demonstrated to be necessary for the proper assembly of the ribosome in bacteria and eukaryotes. Here, we show that the essential GTPases YphC and YsxC are required for large ribosomal subunit biogenesis in
Bacillus subtilis
. Sucrose density gradient centrifugation of large ribosomal subunits isolated from YphC-depleted cells and YsxC-depleted cells indicates that they are similar to the 45S intermediate previously identified in RbgA-depleted cells. The sedimentation of the large-subunit intermediate isolated from YphC-depleted cells was identical to the intermediate found in RbgA-depleted cells, while the intermediate isolated from YsxC-depleted cells sedimented slightly slower than 45S, suggesting that it is a novel intermediate. Analysis of the protein composition of the large-subunit intermediates isolated from either YphC-depleted cells or YsxC-depleted cells indicated that L16 and L36 are missing. Purified YphC and YsxC are able to interact with the ribosome in vitro, supporting a direct role for these two proteins in the assembly of the 50S subunit. Our results indicate that, as has been demonstrated for
Saccharomyces cerevisiae
ribosome biogenesis, bacterial 50S ribosome assembly requires the function of multiple essential GTPases.
A Multicenter Study Evaluating the Current Strategies for Isolating
Staphylococcus aureus
Strains with Reduced Susceptibility to Glycopeptides
Authors: Wootton Mandy , MacGowan Alasdair P. , Walsh Timothy R. , Howe Robin A.
Published: November 2006

Glycopeptide-intermediate
Staphylococcus aureus
(GISA) and heterogeneous GISA (hGISA) strains are notoriously difficult to detect in the diagnostic laboratory. The clinical importance of GISA, and particularly hGISA, will only be obvious when a definitive detection method is available. A few novel GISA and hGISA detection methods have been proposed; however, their validity has never been tested on a significant scale and in different laboratories. This study compares three screening methods for detecting GISA and hGISA strains in 12 laboratories, using a blind panel of 48 strains with known glycopeptide susceptibilities. The three screening methods used were brain heart infusion agar with 6 mg/liter vancomycin (BHIA6V) (CDC/CLSI), Mueller-Hinton agar with 5 mg/liter teicoplanin (MHA5T) (European Antimicrobial Resistance Surveillance System [EARSS]), and the macrodilution method Etest (MET) (EARSS), with population analysis profile-area under the curve analysis as the gold standard. Sensitivity and specificity were highest for MHA5T and MET, which identified 82.5% and 85.9% of strains, respectively. BHIA6V had poor sensitivity, particularly for hGISA (11.5% of strains were detected), and gave the largest interlaboratory variation in performance. MET exhibited the least interlaboratory variation. It is essential that laboratories use appropriate methods to detect GISA/hGISA strains so that the prevalence and clinical importance of these strains can be assessed properly.
Precise Identification of a Human Immunodeficiency Virus Type 1 Antigen Processing Mutant
Authors: Zimbwa Peter , Milicic Anita , Frater John , Scriba Thomas J. , Willis Antony , Goulder Philip J. R. , Pillay Tilly , Gunthard Huldrych , Weber Jonathan N. , Zhang Hua-Tang , Phillips Rodney E.
Published: November 2006

Human immunodeficiency virus type 1 (HIV-1) evokes a strong immune response, but the virus persists. Polymorphisms within known antigenic sites result in loss of immune recognition and can be positively selected. Amino acid variation outside known HLA class I restricted epitopes can also enable immune escape by interfering with the processing of the optimal peptide antigen. However, the lack of precise rules dictating epitope generation and the enormous genetic diversity of HIV make prediction of processing mutants very difficult. Polymorphism E169D in HIV-1 reverse transcriptase (RT) is significantly associated with HLA-B*0702 in HIV-1-infected individuals. This polymorphism does not map within a known HLA-B*0702 epitope; instead, it is located five residues downstream of a HLA-B*0702-restricted epitope SPAIFQSSM (SM9). Here we investigate the association between E169D and HLA-B*0702 for immune escape via the SM9 epitope. We show that this single amino acid variation prevents the immune recognition of the flanked SM9 epitope by cytotoxic T cells through lack of generation of the epitope, which is a result of aberrant proteasomal cleavage. The E169D polymorphism also maps within and abrogates the recognition of an HLA-A*03-restricted RT epitope MR9. This study highlights the potential for using known statistical associations as indicators for viral escape but also the complexity involved in interpreting the immunological consequences of amino acid changes in HIV sequences.
Intraspecies Host Specificity of a Single-Stranded RNA Virus Infecting a Marine Photosynthetic Protist Is Determined at the Early Steps of Infection
Authors: Mizumoto Hiroyuki , Tomaru Yuji , Takao Yoshitake , Shirai Yoko , Nagasaki Keizo
Published: November 2006

Viruses are extremely abundant in seawater and are believed to be significant pathogens to photosynthetic protists (microalgae). Recently, several novel RNA viruses were found to infect marine photosynthetic protists; one of them is HcRNAV, which infects
Heterocapsa circularisquama
(
Dinophyceae
). There are two distinct ecotypes of HcRNAV with complementary intraspecies host ranges. Nucleotide sequence comparison between them revealed remarkable differences in the coat protein coding gene resulting in a high frequency of amino acid substitutions. However, the detailed mechanism supporting this intraspecies host specificity is still unknown. In this study, virus inoculation experiments were conducted with compatible and incompatible host-virus combinations to investigate the mechanism determining intraspecies host specificity. Cells were infected by adding a virus suspension directly to a host culture or by transfecting viral RNA into host cells by particle bombardment. Virus propagation was monitored by Northern blot analysis with a negative-strand-specific RNA probe, transmission electron microscopy, and a cell lysis assay. With compatible host-virus combinations, propagation of infectious progeny occurred regardless of the inoculation method used. When incompatible combinations were used, direct addition of a virus suspension did not even result in viral RNA replication, while in host cells transfected with viral RNA, infective progeny virus particles with a host range encoded by the imported viral RNA were propagated. This indicates that the intraspecies host specificity of HcRNAV is determined by the upstream events of virus infection. This is the first report describing the reproductive steps of an RNA virus infecting a photosynthetic protist at the molecular level.
Oncolytic Virotherapy Synergism with Signaling Inhibitors: Rapamycin Increases Myxoma Virus Tropism for Human Tumor Cells
Authors: Stanford Marianne M. , Barrett John W. , Nazarian Steven H. , Werden Steven , McFadden Grant
Published: November 2006

Myxoma virus is a rabbit-specific poxvirus pathogen that also exhibits a unique tropism for human tumor cells and is dramatically oncolytic for human cancer xenografts. Most tumor cell lines tested are permissive for myxoma infection in a fashion intimately tied to the activation state of Akt kinase. A host range factor of myxoma virus, M-T5, directly interacts with Akt and mediates myxoma virus tumor cell tropism. mTOR is a regulator of cell growth and metabolism downstream of Akt and is specifically inhibited by rapamycin. We report that treatment of nonpermissive human tumor cell lines, which normally restrict myxoma virus replication, with rapamycin dramatically increased virus tropism and spread in vitro. This increased myxoma replication is concomitant with global effects on mTOR signaling, specifically, an increase in Akt kinase. In contrast to the effects on human cancer cells, rapamycin does not increase myxoma virus replication in rabbit cell lines or permissive human tumor cell lines with constitutively active Akt. This indicates that rapamycin increases the oncolytic capacity of myxoma virus for human cancer cells by reconfiguring the internal cell signaling environment to one that is optimal for productive virus replication and suggests the possibility of a potentially therapeutic synergism between kinase signaling inhibitors and oncolytic poxviruses for cancer treatment.
Kaposi's Sarcoma-Associated Herpesvirus-Encoded Protein Kinase and Its Interaction with K-bZIP
Authors: Izumiya Yoshihiro , Izumiya Chie , Van Geelen Albert , Wang Don-Hong , Lam Kit S. , Luciw Paul A. , Kung Hsing-Jien
Published: November 2006

The oncogenic herpesvirus, Kaposi's sarcoma-associated herpesvirus, also identified as human herpesvirus 8, contains genes producing proteins that control transcription and influence cell signaling. Open reading frame 36 (ORF36) of this virus encodes a serine/threonine protein kinase, which is designated the viral protein kinase (vPK). Our recent efforts to elucidate the role of vPK in the viral life cycle have focused on identifying viral protein substrates and determining the effects of vPK-mediated phosphorylation on specific steps in viral replication. The vPK gene was transcribed into 4.2-kb and 3.6-kb mRNAs during the early and late phases of viral reactivation. vPK is colocalized with viral DNA replication/transcription compartments as marked by a polymerase processivity factor, and K-bZIP, a protein known to bind the viral DNA replication origin (Ori-Lyt) and to regulate viral transcription. The vPK physically associated with and strongly phosphorylated K-bZIP at threonine 111, a site also recognized by the cyclin-dependent kinase Cdk2. Both K-bZIP and vPK were corecruited to viral promoters targeted by K-bZIP as well as to the Ori-Lyt region. Phosphorylation of K-bZIP by vPK had a negative impact on K-bZIP transcription repression activity. The extent of posttranslational modification of K-bZIP by sumoylation, a process that influences its repression function, was decreased by vPK phosphorylation at threonine 111. Our data thus identify a new role of vPK as a modulator of viral transcription.
Immunogenicity and Protective Efficacy of DNA Vaccines Expressing Rhesus Cytomegalovirus Glycoprotein B, Phosphoprotein 65-2, and Viral Interleukin-10 in Rhesus Macaques
Authors: Yue Yujuan , Kaur Amitinder , Eberhardt Meghan K. , Kassis Nadine , Zhou Shan Shan , Tarantal Alice F. , Barry Peter A.
Published: November 2006

Rhesus cytomegalovirus (RhCMV) infection of macaques exhibits strong similarities to human CMV (HCMV) persistence and pathogenesis. The immunogenicity of DNA vaccines encoding three RhCMV proteins (a truncated version of glycoprotein B lacking the transmembrane region and endodomain [gBΔTM], phosphoprotein 65-2 [pp65-2], and viral interleukin-10 [vIL-10]) was evaluated in rhesus macaques. Two groups of monkeys (four per group) were genetically immunized four times with a mixture of either pp65-2 and gBΔTM or pp65-2, vIL-10, and gBΔTM. The vaccinees developed anti-gB and anti-pp65-2 antibodies in addition to pp65-2 cellular responses after the second booster immunization, with rapid responses observed with subsequent DNA injections. Weak vIL-10 immune responses were detected in two of the four immunized animals. Neutralizing antibodies were detected in seven monkeys, although titers were weak compared to those observed in naturally infected animals. The immunized monkeys and naïve controls were challenged intravenously with 10
5
PFU of RhCMV. Anamnestic binding and neutralizing antibody responses were observed 1 week postchallenge in the vaccinees. DNA vaccination-induced immune responses significantly decreased peak viral loads in the immunized animals compared to those in the controls. No difference in peak viral loads was observed between the pp65-2/gBΔTM DNA- and pp65-2/vIL-10/gBΔTM-vaccinated groups. Antibody responses to nonvaccine antigens were lower postchallenge in both vaccine groups than in the controls, suggesting long-term control of RhCMV protein expression. These data demonstrated that DNA vaccines targeting the RhCMV homologues of HCMV gB and pp65 altered the course of acute and persistent RhCMV infection in a primate host.
Retinoic Acid-Inducible Gene I Mediates Early Antiviral Response and Toll-Like Receptor 3 Expression in Respiratory Syncytial Virus-Infected Airway Epithelial Cells
Authors: Liu Ping , Jamaluddin Mohammad , Li Kui , Garofalo Roberto P. , Casola Antonella , Brasier Allan R.
Published: November 2006

Respiratory syncytial virus (RSV) is one of the most common viral pathogens causing severe lower respiratory tract infections in infants and young children. Infected host cells detect and respond to RNA viruses using different mechanisms in a cell-type-specific manner, including retinoic acid-inducible gene I (RIG-I)-dependent and Toll-like receptor (TLR)-dependent pathways. Because the relative contributions of these two pathways in the recognition of RSV infection are unknown, we examined their roles in this study. We found that RIG-I helicase binds RSV transcripts within 12 h of infection. Short interfering RNA (siRNA)-mediated RIG-I “knockdown” significantly inhibited early nuclear factor-κB (NF-κB) and interferon response factor 3 (IRF3) activation 9 h postinfection (p.i.). Consistent with this finding, RSV-induced beta interferon (IFN-β), interferon-inducible protein 10 (IP-10), chemokine ligand 5 (CCL-5), and IFN-stimulated gene 15 (ISG15) expression levels were decreased in RIG-I-silenced cells during the early phase of infection but not at later times (18 h p.i.). In contrast, siRNA-mediated TLR3 knockdown did not affect RSV-induced NF-κB binding but did inhibit IFN-β, IP-10, CCL-5, and ISG15 expression at late times of infection. Further studies revealed that TLR3 knockdown significantly reduced NF-κB/RelA transcription by its ability to block the activating phosphorylation of NF-κB/RelA at serine residue 276. We further found that TLR3 induction following RSV infection was regulated by RIG-I-dependent IFN-β secreted from infected airway epithelial cells and was mediated by both IFN response-stimulated element (ISRE) and signal transducer and activator of transcription (STAT) sites in its proximal promoter. Together these findings indicate distinct temporal roles of RIG-I and TLR3 in mediating RSV-induced innate immune responses, which are coupled to distinct pathways controlling NF-κB activation.