bluuebunny/crossref_metadata_2025 huggingface dataset:
Voice Activity and Participation Profile
Authors: Ma Estella P-M. , Yiu Edwin M-L.
Published: April 2006

Traditional clinical voice evaluation focuses primarily on the severity of voice impairment, with little emphasis on the impact of voice disorders on the individual’s quality of life. This study reports the development of a 28-item assessment tool that evaluates the perception of voice problem, activity limitation, and participation restriction using the International Classification of Impairments, Disabilities and Handicaps-2 Beta-1 concept (World Health Organization, 1997). The questionnaire was administered to 40 subjects with dysphonia and 40 control subjects with normal voices. Results showed that the dysphonic group reported significantly more severe voice problems, limitation in daily voice activities, and restricted participation in these activities than the control group. The study also showed that the perception of a voice problem by the dysphonic subjects correlated positively with the perception of limitation in voice activities and restricted participation. However, the self-perceived voice problem had little correlation with the degree of voice-quality impairment measured acoustically and perceptually by speech pathologists. The data also showed that the aggregate scores of activity limitation and participation restriction were positively correlated, and the extent of activity limitation and participation restriction was similar in all except the job area. These findings highlight the importance of identifying and quantifying the impact of dysphonia on the individual’s quality of life in the clinical management of voice disorders.
The Effects of Changes in Hearing Status in Cochlear Implant Users on the Acoustic Vowel Space and CV Coarticulation
Authors: Lane Harlan , Matthies Melanie , Perkell Joseph , Vick Jennell , Zandipour Majid
Published: April 2006

In order to examine the role of hearing status in controlling coarticulation, eight English vowels in /bVt/ and /dVt/ syllables, embedded in a carrier phrase, were elicited from 7 postlingually deafened adults and 2 speakers with normal hearing. The deaf adults served in repeated recording sessions both before and up to a year after they received cochlear implants and their speech processors were turned on. Each of the two hearing control speakers served in two recording sessions, separated by about 3 months. Measures were made of second formant frequency at obstruent release and at 25 ms intervals until the final obstruent.

An index of coarticulation, based on the ratio of F2 at vowel onset to F2 at midvowel target, was computed. Changes in the amount of coarticulation after the change in hearing status were small and nonsystematic for the /bVt/ syllables; those for the /dVt/ syllables averaged a 3% increase—within the range of reliability measures for the 2 hearing control speakers. Locus equations (F2 at vowel onset vs. F2 at vowel midpoint) and ratios of F2 onsets in point vowels were also calculated. Like the index of coarticulation, these measures tended to confirm that hearing status had little if any effect on coarticulation in the deaf speakers, consistent with the hypothesis that hearing does not play a direct role in regulating anticipatory coarticulation in adulthood.

With the restoration of some hearing, 2 implant users significantly increased the average spacing between vowels in the formant plane, whereas the remaining 5 decreased that measure. All speakers but one also reduced vowel duration significantly. Four of the speakers reduced dispersion of vowel formant values around vowel midpoint means, but the other 3 did not show this effect.
The Effect of Target-Selection Strategy on Phonological Learning
Authors: Rvachew Susan , Nowak Michele
Published: April 2006

In this study, 48 children with moderate or severe delays in phonological ability received treatment for four phonemes, selected in accordance with either traditional or nontraditional target-selection criteria. Children who received treatment for phonemes that are early developing and associated with greater productive phonological knowledge showed greater progress toward acquisition of the target sounds than did children who received treatment for late-developing phonemes that were associated with little or no productive phonological knowledge. Between-group differences in generalization learning were not observed. Child enjoyment of therapy did not differ between groups, but parental satisfaction with treatment progress was greater for children in the traditional group than for children in the nontraditional group.
Effects of Abdominal Trussing on Breathing and Speech in Men With Cervical Spinal Cord Injury
Authors: Watson Peter J. , Hixon Thomas J.
Published: April 2006

Abdominal trussing constitutes an inward fixation of the abdominal wall. In the context of speech habilitation/rehabilitation, it is sometimes used to supplant, in part, the function of a paralyzed or paretic abdominal wall. A paralyzed or paretic abdominal wall may be found in individuals with cervical spinal cord injury or in individuals with other neurologic disorders, such as muscular dystrophy. This research was designed to study the effects of trussing as a clinical treatment. A study was designed to systematically and precisely place the abdominal wall at one position (50% inward) to study the effects of trussing (as compared to an untrussed condition) on lung volume and oral reading in three men with cervical spinal cord injury (C5–C6). Results showed that abdominal trussing increased vital capacity, realized via an increase of inspiratory capacity, presumably by optimization of the function of the diaphragm. With the increase in inspiratory capacity, longer utterance duration for oral reading was observed. With increased utterance duration, more syllables were produced per utterance, and pauses occurred at appropriate linguistic locations. Oral reading samples for trussed and untrussed conditions were submitted to preference judgment by a group of 10 judges. For two of the three men studied, oral reading during trussing was preferred because of longer phrases and pauses taken at suitable linguistic boundaries. The findings from this study support clinical impressions that abdominal trussing may be useful in improving speech in individuals with a paralyzed or paretic abdomen whose breathing function for speech is diminished.
Acoustic Patterns of Infant Vocalizations Expressing Emotions and Communicative Functions
Authors: Papaeliou C. , Minadakis G. , Cavouras D.
Published: April 2006

The present study aimed at identifying the acoustic pattern of vocalizations, produced by 7- to 11-month-old infants, that were interpreted by their mothers as expressing emotions or communicative functions. Participants were 6 healthy, first-born English infants, 3 boys and 3 girls, and their mothers. The acoustic analysis of the vocalizations was performed using a pattern recognition (PR) software system. A PR system not only calculates signal features, it also automatically detects patterns in the arrangement of such features. The following results were obtained: (a) the PR system distinguished vocalizations interpreted as emotions from vocalizations interpreted as communicative functions with an overall accuracy of 87.34%; (b) the classification accuracy of the PR system for vocalizations that convey emotions was 85.4% and for vocalizations that convey communicative functions was 89.5%; and (c) compared to vocalizations that express emotions, vocalizations that express communicative functions were shorter, displayed lower fundamental frequency values, and had greater overall intensity. These findings suggest that in the second half of the first year, infants possess a vocal repertoire that contributes to regulating cooperative interaction with their mothers, which is considered one of the major prerequisites for language acquisition.
Listening Effort and Fatigue in School-Age Children With and Without Hearing Loss
Authors: Hicks Candace Bourland , Tharpe Anne Marie
Published: April 2006

Parents, audiologists, and educators have long speculated that children with hearing loss must expend more effort and, therefore, fatigue more easily than their peers with normal hearing when listening in adverse acoustic conditions. Until now, however, very few studies have been conducted to substantiate these speculations. Two experiments were conducted with school-age children with mild-to-moderate hearing loss and with normal hearing. In the first experiment, salivary cortisol levels and a self-rating measure were used to measure fatigue. Neither cortisol measurements nor self-rated measures of fatigue revealed significant differences between children with hearing loss and their normalhearing peers. In the second experiment, however, a dual-task paradigm used to study listening effort indicated that children with hearing loss expend more effort in listening than children with normal hearing. Results are discussed in terms of clinical application and future research needs.
A Family Aggregation Study
Authors: Choudhury Naseem , Benasich April Ann
Published: April 2006

Substantial evidence continues to accrue for familial transmission of specific language impairment (SLI). The incidence in families with a history of SLI is estimated at approximately 20%–40%, whereas in the general population the estimated incidence is about 4%. Typical aggregation studies compare data on the speech and language status of parents and siblings of individuals with SLI (the probands) to similar data from family members of control individuals with no speech or language disorder history. In the present study, family aggregation of SLI was examined for a unique sample of children who were ascertained before 6 months of age and thus did not have SLI, but were born into a family with a positive history of SLI (FH+). No study to date has examined the pattern of affectance in families of children ascertained at such a young age. In addition, the ratio of boys to girls born into such families was investigated, as previous studies have suggested alterations in the expected gender ratios. Consistent with prior research, SLI was found to aggregate in families; the average affectance rate in FH+families was 32%, with significantly more boys (41%) reported as having SLI than girls (16%). A comparison of FH+and control families (FH–) on sociodemographic factors and medical history revealed differences in the overall rate of autoimmune diseases; FH+families reported a significantly higher incidence (35%) compared to FH– families (9%). Finally, the 3- year language abilities of a subset of 32 children from FH+families were compared with those of 60 children from FH– families. Children from FH+families scored significantly lower on standardized measures of language and were more likely to fall below the 16th percentile (28%) than children from FH– families (7%). These results provide converging evidence that children from FH+families are indeed at greater risk of developing language delay compared to children from control families.
Talker and Lexical Effects on Audiovisual Word Recognition by Adults With Cochlear Implants
Authors: Kaiser Adam R. , Kirk Karen Iler , Lachs Lorin , Pisoni David B.
Published: April 2006

The present study examined how postlingually deafened adults with cochlear implants combine visual information from lipreading with auditory cues in an open-set word recognition task. Adults with normal hearing served as a comparison group. Word recognition performance was assessed using lexically controlled word lists presented under auditory-only, visual-only, and combined audiovisual presentation formats. Effects of talker variability were studied by manipulating the number of talkers producing the stimulus tokens. Lexical competition was investigated using sets of lexically easy and lexically hard test words. To assess the degree of audiovisual integration, a measure of visual enhancement, R
a
, was used to assess the gain in performance provided in the audiovisual presentation format relative to the maximum possible performance obtainable in the auditory-only format. Results showed that word recognition performance was highest for audiovisual presentation followed by auditory-only and then visual-only stimulus presentation. Performance was better for single-talker lists than for multiple-talker lists, particularly under the audiovisual presentation format. Word recognition performance was better for the lexically easy than for the lexically hard words regardless of presentation format. Visual enhancement scores were higher for single-talker conditions compared to multiple-talker conditions and tended to be somewhat better for lexically easy words than for lexically hard words. The pattern of results suggests that information from the auditory and visual modalities is used to access common, multimodal lexical representations in memory. The findings are discussed in terms of the complementary nature of auditory and visual sources of information that specify the same underlying gestures and articulatory events in speech.
Verbal and Spatial Information Processing Constraints in Children With Specific Language Impairment
Authors: Hoffman LaVae M. , Gillam Ronald B.
Published: April 2006

A dual-processing paradigm was used to investigate information processing limitations underlying specific language impairment (SLI). School-age children with and without SLI were asked to recall verbal and spatial stimuli in situations that varied the number of tasks that were required and the speed at which stimuli were presented. Children recalled digits or locations of X's that were presented on a computer screen. In some conditions, they were asked to name or point to the color of the stimuli before completing the recall task. In comparison to their typically developing peers, children with SLI had generally poorer recall of digits and locations across all conditions. Typically developing children derived greater benefit than the children with SLI under conditions that enabled them to disperse processing efforts across verbal and spatial response modalities. It appears that limitations in general cognitive capacity and central executive functions in working memory work synergistically with response modality to constrain information processing in children with SLI.
A Prosodically Controlled Word and Nonword Repetition Task for 2- to 4-Year-Olds
Authors: Roy Penny , Chiat Shula
Published: April 2006

An association has been found between nonword repetition and language skills in school-age children with both typical and atypical language development (C. Dollaghan & T. F. Campbell, 1998; S. Ellis Weismer et al., 2000; S. E. Gathercole & A. D. Baddeley, 1990; J. W. Montgomery, 2002). This raises the possibility that younger children's repetition performance may be predictive of later language deficits. In order to investigate this possibility, it is important to establish that elicited repetition with very young children is both feasible and informative. To this end, a repetition task was designed and carried out with 66 children between 2 and 4 years of age. The task consisted of 18 words and 18 matched nonwords that were systematically manipulated for length and prosodic structure. In addition, an assessment of receptive vocabulary was administered.

The repetition task elicited high levels of response. Total scores as well as word and nonword scores were sensitive to age. Lexical status and item length affected performance regardless of age: Words were repeated more accurately than nonwords, and 1-syllable items were repeated more accurately than 2-syllable items, which were in turn repeated more accurately than 3-syllable items. The effect of prosodic structure was also significant. Whole syllable errors were almost exclusive to unstressed syllables, with those preceding stress being most vulnerable. Performance on the repetition task was significantly correlated with performance on the receptive vocabulary test. This repetition task effectively elicited responses from most of the 2- to 4-year-old participants, tapped developmental change in their repetition skills, and revealed patterns in their performance; and thus it has the potential to identify deficits in very early repetition skills that may be indicative of wider language difficulties.
How Well Can Children Recognize Speech Features in Spectrograms? Comparisons by Age and Hearing Status
Authors: Ertmer David J.
Published: April 2006

Real-time spectrographic displays (SDs) have been used in speech training for more than 30 years with adults and children who have severe and profound hearing impairments. Despite positive outcomes from treatment studies, concerns remain that the complex and abstract nature of spectrograms may make these speech training aids unsuitable for use with children. This investigation examined how well children with normal hearing sensitivity and children with impaired hearing can recognize spectrographic cues for vowels and consonants, and the ages at which these visual cues are distinguished. Sixty children (30 with normal hearing sensitivity, 30 with hearing impairments) in 3 age groups (6–7, 8–9, and 10–11 years) were familiarized with the spectrographic characteristics of selected vowels and consonants. The children were then tested on their ability to select a match for a model spectrogram from among 3 choices. Overall scores indicated that spectrographic cues were recognized with greater-than-chance accuracy by all age groups. Formant contrasts were recognized with greater accuracy than consonant manner contrasts. Children with normal hearing sensitivity and those with hearing impairment performed equally well.
Present Tense
Be
Use in Young Children With Specific Language Impairment
Authors: Beverly Brenda L. , Williams Cynthia C.
Published: April 2006

A well-known characteristic of children with specific language impairment (SLI) is a significant deficit in grammatical morphology production compared with younger, language-matched, typically developing children. This is true for present tense
be (am, is, are
), as well as other inflectional morphemes. However, grammatical morpheme learning by children with SLI may vary depending on developmental stage. Participants were 8 boys with SLI (42 to 58 months old with mean length of utterances [MLUs] ≤ 3.0 morphemes) and 14 MLU-matched controls (girls and boys; mean age of 27 months). These groups were younger and had lower MLUs than groups from oft-cited studies (e.g., Cleave & Rice, 1997; Leonard, Bortolini, Caselli, McGregor, & Sabbadini, 1992; Leonard, Eyer, Bedore, & Grela, 1997; Rice, Wexler, & Hershberger, 1998). The SLI group had a significantly higher percentage of
be
use in obligatory contexts (46%) than did the younger, typically developing children (27%). This pattern of better performance in grammatical morphology by SLI groups than controls has been reported. Ingram (1972) and Morehead and Ingram (1973) found similar results for children with language impairment in early-MLU stages. Although findings are presented with caution, they afford an opportunity to consider the nature of SLI. If SLI represents a general processing limitation, then that limitation might enable the language learner with SLI to acquire some initial morphological mappings with relative success. This apparent paradox, which also is evident in normal language acquisition, has been termed
less is more
by Newport (1990). Limited perception and memory force attention to smaller pieces of the input, and these constraints simplify the task for the language learner. SLI is compared with a chronically constrained system that initially assists the learner to achieve basic form-function mappings but ultimately hinders mastery of English morphology.
In Search of the Auditory, Phonetic, and/or Phonological Problems in Dyslexia
Authors: Blomert Leo , Mitterer Holger , Paffen Christiaan
Published: April 2006

There is a growing consensus that developmental dyslexia is associated with a phonological-core deficit. One symptom of this phonological deficit is a subtle speech-perception deficit. The auditory basis of this deficit is still hotly debated. If people with dyslexia, however, do not have an auditory deficit and perceive the underlying acoustic dimensions of speech as well as people who read normally, then why do they exhibit a categorical-perception deficit? A potential answer to this conundrum lies in the possibility that people with dyslexia do not adequately handle the context-dependent variation that speech signals typically contain. A mathematical model simulating such a sensitivity deficit mimics the speech-perception deficits attributed to dyslexia. To assess the nature of the dyslexic problem, the authors examined whether children with dyslexia handle context dependencies in speech differently than do normal-reading individuals. Contrary to the initial hypothesis, children with dyslexia did not show less context sensitivity in speech perception than did normal-reading individuals at auditory, phonetic, and phonological levels of processing, nor did they reveal any categorization deficit. Instead, intrinsic properties of online phonological processes, not phonological representations per se, may be impaired in dyslexia.
Role of Vocal Tract Morphology in Speech Development
Authors: Ménard Lucie , Schwartz Jean-Luc , Boë Louis-Jean
Published: April 2006

The development of speech from infancy to adulthood results from the interaction of neurocognitive factors, by which phonological representations and motor control abilities are gradually acquired, and physical factors, involving the complex changes in the morphology of the articulatory system. In this article, an articulatory-to-acoustic model, integrating nonuniform vocal tract growth, is used to describe the effect of morphology in the acoustic and perceptual domains. While simulating mature control abilities of the articulators (freezing neurocognitive factors), the size and shape of the vocal apparatus are varied, to represent typical values of speakers from birth to adulthood. The results show that anatomy does not prevent even the youngest speaker from producing vowels perceived as the 10 French oral vowels /i y u e ø o ε œ a/. However, the specific configuration of the vocal tract for the newborn seems to favor the production of those vowels perceived as low and front. An examination of the acoustic effects of articulatory variation for different growth stages led to the proposed variable sensorimotor maps for newbornlike, childlike, and adultlike vocal tracts. These maps could be used by transcribers of infant speech, to complete existing systems and to provide some hints about underlying articulatory gestures recruited during growth to reach perceptual vowel targets in French.
Trade-Offs Between Informativeness and Speed of Message Delivery in Augmentative and Alternative Communication
Authors: Hoag Linda A. , Bedrosian Jan L. , McCoy Kathleen F. , Johnson Dallas E.
Published: April 2006

This report is the second in a series of investigations designed to develop a working model identifying the effects of trade-offs between selected conversational maxims on public attitudes toward augmentative and alternative communication (AAC) system users and their communication. In the current study, tradeoffs between the informativeness of a prestored message and its speed of delivery were examined. A total of 96 salesclerks participated. Sixteen scripted, videotaped conversational conditions, involving an AAC customer and a clerk at a checkout counter, were used to manipulate message informativeness and speed of message delivery. Following each assigned viewing, participants completed a questionnaire designed to assess their attitudes toward the AAC user and his or her communication. The conditions involving (a) the quickly delivered message with excessive information, (b) the slowly delivered message with adequate information preceded by a "floorholder," and (c) the slowly delivered message with adequate information without a floorholder were rated higher than (d) the quickly delivered message with inadequate information. There was no main effect for participant or AAC user gender. Implications regarding a model of conversational trade-offs and technological applications are discussed.
Utterance Length and Lexical Diversity in Cantonese-Speaking Children With and Without Specific Language Impairment
Authors: Klee Thomas , Stokes Stephanie F. , Wong Anita M.-Y. , Fletcher Paul , Gavin William J.
Published: April 2006

Two studies of children's conversational language abilities are reported. In the first, mean length of utterance (MLU) and lexical diversity (D) were examined in a group of typically developing Cantonese-speaking children in Hong Kong. Regression analyses indicated a significant linear relationship between MLU and age (
R
= .44) and a significant curvilinear relationship between D and age (
R
= .73) in children age 27–68 months. MLU and D were moderately correlated with each other (
r
= .23); however, the two measures showed no statistical relationship when the effect of age was partialled out. In a second study, the utterances of Chinese children with specific language impairment (SLI) were found to be significantly shorter and less lexically diverse than typically developing children matched for age but similar to children matched for comprehension level. Discriminant analyses revealed that the combination of age, MLU, and D could be used to accurately differentiate children with SLI from both age-matched and language-matched children. Based on these findings, we hypothesize that these measures can be used jointly as a marker of SLI in Cantonese-speaking children.
A Phonemic Implicational Feature Hierarchy of Phonological Contrasts for English-Speaking Children
Authors: Stokes Stephanie F. , Klee Thomas , Carson Cecyle Perry , Carson David
Published: April 2006

Contrastive feature hierarchies have been developed and used for some time in depicting typical phonological development and in guiding therapy decisions. Previous descriptions of feature use have been based on independent analyses and usually phonetic inventories. However, recent trends in phonology include a relational analysis of phonemic inventories (D. Ingram & K. D. Ingram, 2001). The current investigation was a relational analysis of the phonemic inventories of 40 typically developing 2-year-old American-English-speaking children. Consonant inventories were derived from spontaneous speech samples using the Logical International Phonetics Programs computer software (D. K. Oller & R. E. Delgado, 1999). Cluster analysis was used to determine the grouping of contrastive features. Four levels emerged. Level I included [consonant], [sonorant], and [coronal], Level II included [voice], Level III included [anterior], [continuant], and [nasal], and Level IV included [lateral] and [strident]. Results suggested that the resulting 4-level phonemic feature hierarchy might be used to classify the phonological systems of children with phonological disorders.
Categorical Perception of Speech by Children With Specific Language Impairments
Authors: Coady Jeffry A. , Kluender Keith R. , Evans Julia L.
Published: April 2006

Previous research has suggested that children with specific language impairments (SLI) have deficits in basic speech perception abilities, and this may be an underlying source of their linguistic deficits. These findings have come from studies in which perception of synthetic versions of meaningless syllables was typically examined in tasks with high memory demands. In this study, 20 children with SLI (mean age=9 years, 3 months) and 20 age-matched peers participated in a categorical perception task. Children identified and discriminated digitally edited versions of naturally spoken real words in tasks designed to minimize memory requirements. Both groups exhibited all hallmarks of categorical perception: a sharp labeling function, discontinuous discrimination performance, and discrimination predicted from identification. There were no group differences for identification data, but children with SLI showed lower peak discrimination values. Children with SLI still discriminated phonemically contrastive pairs at levels significantly better than chance, with discrimination of same-label pairs at chance. These data suggest that children with SLI perceive natural speech tokens comparably to age-matched controls when listening to words under conditions that minimize memory load. Further, poor performance on speech perception tasks may not be due to a speech perception deficit, but rather to a consequence of task demands.
Prelinguistic Predictors of Vocabulary in Young Children With Autism Spectrum Disorders
Authors: McDuffie Andrea , Yoder Paul , Stone Wendy
Published: April 2006

Purpose:
The goal of the current study was to identify a predictive model of vocabulary comprehension and production in a group of young children with autism spectrum disorders. Four prelinguistic behaviors were selected for consideration as predictors based on theoretical and empirical support for the relationship of these behaviors to language development.

Method:
The study used a longitudinal correlational design. Participants were twenty-nine 2- and 3-year-olds diagnosed with autism spectrum disorders. The prelinguistic behaviors—attention-following, motor imitation, commenting, and requesting—were measured at the initial visit. Vocabulary comprehension and production were measured 6 months later.

Results:
Commenting was the only unique predictor of comprehension after the degree of cognitive delay was controlled. Both commenting and motor imitation of actions without objects were unique predictors of production over and above the other skills and when the degree of cognitive delay was controlled.

Conclusions:
The finding that both commenting and motor imitation simultaneously accounted for unique variance in vocabulary production is new to the literature and requires replication. However, results suggest that increasing behaviors that allow children with autism to make their current focus of attention obvious to social partners may be an effective approach for supporting word learning in young children with autism.
Diffusion in multilayer media: Transient behavior of the lateral diffusion coefficient
Authors: Berezhkovskii Alexander M. , Weiss George H.
Published: April 2006

A general formalism for treating lateral diffusion in a multilayer medium is developed. The formalism is based on the relation between the lateral diffusion and the distribution of the cumulative residence time, which the diffusing particle spends in different layers. We exploit this fact to derive general expressions which give the global and local time-dependent diffusion coefficients in terms of the average cumulative times spent by the particle in different layers and the probabilities of finding the particle in different layers, respectively. These expressions are used to generalize two recently obtained results: (a) A solution for the short-time behavior of the lateral diffusion coefficient in two layers separated by a permeable membrane obtained by a perturbation theory is extended to the entire range of time. (b) A solution for the time-dependent diffusion coefficient of a ligand, which repeatedly dissociates and rebinds to sites on a planar surface, obtained under the assumption that the medium above the surface is infinite, is generalized to allow for the medium layer of finite thickness. For the latter problem we derive an expression for the Fourier-Laplace transform of the propagator in terms of the double Laplace transform of the probability density of the cumulative residence time spent by the ligand in the medium layer.
First characterization of silicon crystalline fibers produced with the μ-pulling technique for future gravitational wave detectors
Authors: Alshourbagy M. , Amico P. , Bosi L. , Cagnoli G. , Campagna E. , Cottone F. , Dari A. , Gammaitoni L. , Lorenzini M. , Losurdo G. , Marchesoni F. , Martelli F. , Piergiovanni F. , Punturo M. , Toncelli A. , Tonelli M. , Travasso F. , Vetrano F. , Vocca H.
Published: April 2006

The design of the gravitational wave interferometric detectors of third generation is under way. An overall improvement of the detector performance can be obtained by reducing a few noise sources, such as seismic noise, shot noise, and most importantly thermal noise. We report here on the design and fabrication of low thermal-noise suspensions made of a new material presently under investigation. An ad hoc technique to produce crystalline silicon fibers has been developed; the first measurements of the fiber mechanical and thermal properties at room temperature have been performed and interpreted. Preliminary measurements of the mechanical losses at low temperature are also discussed.
Genes for the peptidoglycan synthesis pathway are essential for chloroplast division in moss
Authors: Machida Mariko , Takechi Katsuaki , Sato Hiroshi , Chung Sung Jin , Kuroiwa Haruko , Takio Susumu , Seki Motoaki , Shinozaki Kazuo , Fujita Tomomichi , Hasebe Mitsuyasu , Takano Hiroyoshi
Published: April 2006

The general consensus is that a cyanobacterium phagocytosed by a host cell evolved into the plastids of red and green algae, land plants, and glaucophytes. In contrast to the plastids of glaucophytes, which retain a cyanobacterial-type peptidoglycan layer, no wall-like structures have been detected in plastids from other sources. Although the genome of
Arabidopsis thaliana
contains five genes that are essential for peptidoglycan synthesis, MurE, MurG, two genes for
d
-Ala-
d
-Ala ligase (Ddl), and the gene for translocase I (MraY), their functions have not been determined. We report that the moss
Physcomitrella patens
has nine homologous genes related to peptidoglycan biosynthesis: MurA, B, C, D, E, and F, Ddl, genes for the penicillin-binding protein Pbp, and
dd
-carboxypeptidase (Dac). Corroborating a computer prediction, analysis of the GFP fusion proteins with the N terminus of PpMurE or of PpPbp suggests that these proteins are located in the chloroplasts. Gene disruption of the PpMurE gene in
P. patens
resulted in the appearance of macrochloroplasts both in protonema and in leaf cells. Moreover, gene knockout of the
P. patens
Pbp gene showed inhibition of chloroplast division in this moss; however, no Pbp gene was found in
A. thaliana
.
Clinical and Epidemiologic Features of Methicillin-Resistant Staphylococcus aureus in Elderly Hospitalized Patients
Authors: Simor Andrew E. , Ofner-Agostini Marianna , Paton Shirley , McGeer Allison , Loeb Mark , Bryce Elizabeth , Mulvey Michael
Published: April 2006

We describe characteristics of elderly patients with MRSA identified in 37 Canadian hospitals between 1995 and 2002. Of these inpatients, 6,613 (66%) were older than 65 years. They were more likely than younger patients to have been colonized without infection and to have had MRSA isolated from urine or the perineum. The epidemiology and clinical features of these patients is distinct from that of younger patients.
Nisin induction without nisin secretion
Authors: Hilmi Hanan T. Abbas , Kylä-Nikkilä Kari , Ra Runar , Saris Per E. J.
Published: April 2006

Nisin Z, a post-translationally modified antimicrobial peptide ofLactococcus lactis, is positively autoregulated by extracellular nisin via the two-component regulatory proteins NisRK. A mutation in the nisin NisT transporter renderedL. lactisincapable of nisin secretion, and nisin accumulated inside the cells. Normally nisin is activated after secretion by the serine protease NisP in the cell wall. This study showed that when secretion of nisin was blocked, intracellular proteolytic activity could cleave the N-terminal leader peptide of nisin precursor, resulting in active nisin. The isolated cytoplasm of a non-nisin producer could also cleave the leader from the nisin precursor, showing that the cytoplasm ofL. lactiscells does contain proteolytic activity capable of cleaving the leader from fully modified nisin precursor. Nisin could not be detected in the growth supernatant of the NisT mutant strain with a nisin-sensing strain (sensitivity 10 pg ml−1), which has a green fluorescent protein gene connected to the nisin-induciblenisApromoter and a functional nisin signal transduction circuit. Northern analysis of the NisT mutant cells revealed that even though the cells could not secrete nisin, the nisin-inducible promoter PnisZwas active. In anisBornisCbackground, where nisin could not be fully modified due to the mutations in the nisin modification machinery, the unmodified or partly modified nisin precursor accumulated in the cytoplasm. This immature nisin could not induce the PnisZpromoter. The results suggest that when active nisin is accumulated in the cytoplasm, it can insert into the membrane and from there extrude parts of the molecule into the pseudoperiplasmic space to interact with the signal-recognition domain of the histidine kinase NisK. Potentially, signal presentation via the membrane represents a general pathway for amphiphilic signals to interact with their sensors for signal transduction.
Where is T5? A survey of anaesthetists*
Authors: Congreve K. , Gardner I. , Laxton C. , Scrutton M.
Published: April 2006

The extent of a regional block for Caesarean section must be tested and documented before surgery commences. In recent years a block to ‘touch’ that includes T5 has increasingly been considered the best predictive test for a pain‐free Caesarean section. Our survey examines the consistency with which different anaesthetists identified the location of the T5 dermatome. Seventy‐three anaesthetists were asked to mark a point on an anatomical picture to indicate where they would test for T5. Overall there was good agreement on the location of the T5 dermatome, but one in seven anaesthetists were inaccurate by two or more dermatomes. There were no statistically significant differences between the subgroups of senior house officer, specialist registrar and consultant anaesthetists. The knowledge of relevant dermatome levels should be an integral part of obstetric anaesthetic training.
The effects of the exaggerated lithotomy position for radical perineal prostatectomy on respiratory mechanics
Authors: Choi S. J. , Gwak M. S. , Ko J. S. , Lee H. , Yang M. , Lee S. M. , Kim G. S. , Kim M. H.
Published: April 2006

The exaggerated lithotomy position is used during radical perineal prostatectomy to increase perineal exposure. The aim of this study was to evaluate the effects of the exaggerated lithotomy position on respiratory mechanics and arterial blood gases. In the exaggerated lithotomy position, dynamic compliance and static compliance were found to be significantly decreased by 27.4% and 34.8%, respectively, whilst peak, plateau, and mean airway pressures increased significantly by 34.0%, 45.8% and 31.7%, respectively. The physiological dead space/tidal volume ratio and total inspiratory work of breathing increased significantly by 11.1% and 33.7%, respectively. Arterial oxygen tension was significantly decreased by 26.9%; however, no significant differences were seen in end‐tidal or arterial carbon dioxide tension. These results indicate that the exaggerated lithotomy position under general anaesthesia can cause significant effects on respiratory system mechanics and arterial oxygenation and highlights the need for careful monitoring of patients placed in this position for surgery.
No effect of homocysteine‐lowering therapy on vascular inflammation and haemostasis in peripheral arterial occlusive disease
Authors: Schernthaner G.‐H. , Plank C. , Minar E. , Bieglmayer C. , Koppensteiner R. , Schernthaner G.
Published: April 2006

Background  Although peripheral arterial occlusive disease (PAOD) is significantly associated with elevated homocysteine levels, the clinical relevance of hyperhomocysteinaemia for the prevention and progression of PAOD is still unknown.

Materials and methods  A total of 65 patients suffering from symptomatic PAOD with elevated homocysteine levels were randomized onto placebo or B‐vitamins (50 mg thiaminhydrochlorid, 50 mg pyridoxine, and 0·05 mg cyanocobalamin), plus 5 mg folic acid daily for 6 weeks. Serum levels of folic acid, vitamin B12, creatinine, ultra‐sensitive C‐reactive protein (usCRP), interleukin (IL)‐6, IL‐8, IL‐18, monocyte‐chemo‐attractant‐protein‐1 (MCP‐1) and plasma levels of homocysteine, tissue factor (TF) and tissue factor pathway inhibitor (TFPI) were determined on the 1st day and 42nd day. Primary outcome was reduction of homocysteine, secondary outcomes were reduction of usCRP, IL‐6, IL‐8, Il‐18, MCP‐1, TF and TFPI.

Results  The mean reduction of homocysteine concentration was 33% (95%CI 33·36–55·76, or 18·9 ± 5·4 µmol L−1−12·6 ± 2·8 µmol L−1, P = 0) in the B‐vitamin group compared with 1% in the placebo group. Folic acid (P = 0) and vitamin B12 (P = 0) increased significantly in the verum group, but both remained unchanged in the control group. No treatment effect of lowering of homocysteine on any markers of haemostasis (TF, TFPI) or inflammation (usCRP, IL‐6, IL‐8, IL‐18 and MCP‐1) was observed.

Conclusion  Although homocysteine is associated with vascular disease risk in the general population and in particular with PAOD, marked lowering of homocysteine concentrations by folic acid and B‐vitamin supplementation does not influence inflammatory responses involving usCRP, IL‐6, IL‐8, IL‐18 and MCP‐1, nor tissue factor. These results provide evidence against a major effect of hyperhomocysteinaemia on vascular chronic inflammation or coagulation in patients with symptomatic peripheral arterial occlusive disease.
Regulation of castasterone level in primary roots of maize, Zea mays
Authors: Kim Young‐Soo , Kim Tae‐Wuk , Chang Soo Chul , Pharis Richard P. , Lee June Seung , Han Tae‐Jin , Takatsuto Suguru , Cheong Hyeonsook , Kim Seong‐Ki
Published: April 2006

Gas chromatography–mass spectrometry analysis revealed that primary roots of maize contain 28‐norcastasterone (28‐norCS) and its biosynthetic precursors, cholesterol, and cholestanol, which suggests that the C27‐brassinosteroid (C27‐BR) biosynthetic pathway to generate 28‐norCS is operative in the roots. A cell‐free enzyme solution prepared from maize roots successfully mediated C24‐methylation of 28‐norCS to produce castasterone (CS) with the aid of S‐adenosyl‐l‐methionine, which indicates that CS can be generated through C27‐BR biosynthesis, as well as C28‐BR biosynthesis, in maize roots. Enzymatic conversion study using the cell‐free enzyme solution demonstrated that CS is converted into 26‐norCS in the enzyme solution. Exogenously applied 28‐norCS and 26‐norCS showed less activity than CS in the activation of gravitropic curvature and inhibition of root elongation. Taken together, a steady‐state level of CS, the active BR in maize roots, seems to be strictly controlled by complicated processes such as C28‐ and C27‐BR biosynthesis and biodegradation by C26‐demethylation to exert its biological activity.
Influence of the injection site (L2/3 or L3/4) and the posture of the vertebral column on selective spinal anesthesia for ambulatory knee arthroscopy
Authors: Korhonen A‐M. , Valanne J. V. , Jokela R. M. , Ravaska P. , Volmanen P. , Korttila K.
Published: April 2006

Background:  We tested the hypothesis that selective spinal anesthesia for ambulatory knee arthroscopy can be accomplished with a small dose of bupivacaine at the L3/4 interspace with or without a head‐down tilt of 5° when the patients were in the lateral decubitus position.

Methods:  In this double‐blind study, 123 patients were randomly allocated to receive spinal anesthesia with 4 mg of hyperbaric bupivacaine inserted at either the L2/3 interspace, while the vertebral column was kept horizontal (L2/3 group), or the L3/4 level, with the vertebral column horizontal (L3/4H) or tilted 5° head‐down (L3/4T). At 7 min, an additional head down tilt was used in all groups if the sensory block was inadequate.

Results:  In the L3/4T group the sensory block (Th8) reached a significantly higher level 30 min after spinal injection, compared with both the L2/3 (Th10) and L3/4H (Th11) groups. In the L3/4H group, 39% of the patients needed an additional tilt for 3 min at 7 min, compared with 10% (P=0.004) in the L3/4T group. Sacral block developed later and recovered faster (P<0.05) in the L3/4T group compared to the L3/4H group. Home‐readiness was achieved equally fast in all groups.

Conclusion:  When producing selective spinal anesthesia, the posture of the vertebral column is a major determinant of both sensory and motor segments to be blocked. A 4‐mg dose of hyperbaric bupivacaine at the L3/4 interspace with a 5° head‐down tilt of the vertebral column for 6 min is recommended for knee arthroscopy.
Toxicological and biochemical characterizations of GSTs in Liposcelis bostrychophila Badonnel (Psocop., Liposcelididae)
Authors: Dou W. , Wang J.‐J. , Zhao Z.‐M.
Published: April 2006

Abstract:  The toxicological and biochemical characteristics of glutathione S‐transferases (GSTs) in the resistant and susceptible strains of Liposcelis bostrychophila were investigated. The two resistant strains were the dichlorvos‐resistant strain (DDVP‐R) and PH3‐resistant strain (PH3‐R), and the resistance factors were 22.36 and 4.51, respectively. Compared with their susceptible counterparts, the activities per insect and specific activities of GSTs in DDVP‐R and PH3‐R were significantly higher. The apparent Michaelis–Menten constant values (Km) for 1‐chloro‐2,4‐dinitrobenzene (CDNB) were obviously lower in DDVP‐R and PH3‐R (i.e. lower Km values, 1.5625 mm for DDVP‐R and 0.6230 mm for PH3‐R) when compared with their susceptible counterpart (Km = 3.5520), indicating a higher affinity to the substrate CDNB in resistant strains. In contrast, the catalytic activity of GSTs towards CDNB in the susceptible strain was significantly higher than those in resistant strains. It was noticeable that when reduced glutathione (GSH) was used as substrate, GSTs from resistant strains both indicated a significantly declined affinity. For the catalytic activity of GSTs towards GSH, only the Vmax value in DDVP‐R increased significantly compared with that from the susceptible strain, suggesting an overexpression of GST in this resistant strain. The inhibition kinetics of insecticides to GSTs in vitro revealed that dichlorvos and paraoxon possessed excellent inhibition effects on GSTs. The susceptible strain showed higher sensitivity (I50 = 0.9004 mm) to dichlorvos than DDVP‐R and PH3‐R (higher I50s, 8.0955 mm for DDVP‐R and 9.3346 mm for PH3‐R). As for paraoxon, there was a similar situation. The resistant strains both suggested a higher I50 (1.8735 mm for DDVP‐R, and 0.4291 mm for PH3‐R) compared with the susceptible strain (0.2943 mm). These suggested that an elevated detoxification ability of GSTs developed in the resistant strains.