bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non-Sibilant Fricatives in English: Spectral Information above 10 kHz
Authors: Tabain Marija 
Published: April 2003

Abstract
The purpose of this study is to explore the contribution of higher frequencies to fricative consonant classification in Australian English. The spectral range above 10 kHz is analysed in an attempt to provide better classifications of the dental and the labiodental fricatives. A comparison is made between real-word data and data from a controlled-word context. Although results for the controlled-word context suggest that spectral information above 10 kHz may be of use in classifying [f] correctly, these results are not repeated for the real-word data. Moreover, classification of [f] and [q] using only the information above 10 kHz yields quite poor results. It is also shown that the results for the voiced dental and labiodental fricatives are not as promising as those for their voiceless counterparts.
Perceiving Final Voiceless Stops without Release: Effects of Preceding Monophthongs versus Nonmonophthongs
Authors: Lisker Leigh 
Published: April 2003

Abstract
Prepausal postvocalic stops in English are reported to occur both with and without audible release bursts, more or less randomly, and this difference is said to be without distinctive function. However, there is evidence that an English final stop, absent its release, may be of reduced intelligibility, particularly as to its place of articulation. Without audible release a final stop’s place is conveyed mainly, perhaps entirely, by frequency shifts in the vowel formants. Among the vowels of English some are diphthongal, a property also signaled by formant shifts. The question arises: Is the intelligibility of an unreleased stop significantly affected by the phonetic nature of the vowel? Perceptual testing of appropriately chosen nonsense monosyllables ending in [p<sup>⌍</sup> t<sup>⌍</sup> k<sup>⌍</sup>] indicates that these stops are generally somewhat less intelligible after diphthongs. However, not all three stops are affected equally, [k<sup>⌍</sup>] perception being especially reduced in this context.
The Phonetic Potential of Nonhuman Vocal Tracts: Comparative Cineradiographic Observations of Vocalizing Animals
Authors: Tecumseh Fitch W. 
Published: April 2003

Abstract
For more than a century it has been noted that the adult human vocal tract differs from that of other mammals, in that the resting position of the larynx is much lower in humans. While animals habitually breathe with the larynx inserted into the nasal cavity, adult humans are unable to do this. This anatomical difference has been cited as an important factor limiting the vocal potential of nonhuman animals, because the low larynx of humans allows a wider range of vocal tract shapes and thus formant patterns than is available to other species. However, it is not clear that the static anatomy of dead animals provides an accurate guide to the phonetic potential of the living animal’s vocal tract. Here I present X-ray video observations of four mammal species (dogs Canis familiaris, goats Capra hircus, pigs Sus scrofa and cotton-top tamarins Sagunius oedipus). In all four species, the larynx was lowered from the nasopharynx, and the velum was closed, during loud calls. In dogs this temporary lowering was particularly pronounced. Although preliminary, these results suggest that the nonhuman vocal tract is more flexible than previously supposed, and that static postmortem anatomy provides an incomplete guide to the phonetic potential of nonhuman animals. The implications of these findings for theories of speech evolution are discussed.
Speech to Infants as Hyperspeech: Knowledge-Driven Processes in Early Word Recognition
Authors: Fernald Anne 
Published: April 2003

AbstractThe intelligibility of a word in continuous speech depends on the clarity of the word and on linguistic and nonlinguistic contextual information available to the listener. Despite limited knowledge of language and the world, infants in the first 2 years are already beginning to make use of contextual information in processing speech. Adults interacting with infants tend to modify their speech in ways that serve to maximize predictability for the immature listener by highlighting focussed words and using frequent repetition and formulaic utterances. Infant-directed speech is viewed as a form of ‘hyperspeech’ which facilities comprehension, not by modifying phonetic properties of individual words but rather by providing contextual support on perceptual levels accessible to infants even in the earliest stages of language learning.
Prognostic Factors in Childhood Intracranial Ependymomas: The Role of Age and Tumor Location
Authors: Sala Francesco , Talacchi Andrea , Mazza Carlo , Prisco Roberto , Ghimenton Claudio , Bricolo Albino 
Published: April 2003

Despite several clinical reports on intracranial ependymomas in children, the factors which affect prognosis, and the possibility that certain combinations of factors might limit survival, are still a matter of debate. Between 1976 and 1996 we operated on 35 children with intracranial ependymomas. Postoperative irradiation was given to 27 patients, with associated chemotherapy in 6 cases. Mean follow-up was 62 months. In 12 patients a 5-year follow-up was possible. In October 1996, 18 patients (51.4%) were still alive, the longest disease-free follow-up being 20 years, and the shortest 8 months. We analyzed the prognostic relevance of eight factors. For each factor, different subgroups were distinguished and compared as follows: age at diagnosis (<4 vs. ≥4 years), sex, tumor location (supratentorial vs. infratentorial), tumor size (<4 vs. 4–7 vs. >7 cm), surgical removal (total vs. subtotal), histology (low-grade vs. anaplastic), morphology (solid vs. cystic), adjuvant therapies (treatment vs. no treatment). Two-way contingency tables were made to identify associations between variables. The only significant association was between age and tumor location (p = 0.022): in children under 4, tumors were almost invariably located in the posterior fossa (9 out of 10 cases) with a clear preference for the lateral recess (8 cases). Other correlations were not significant. Kaplan-Meier survival curves were compared to assess the prognostic relevance of each factor. Survival was significantly lower for children under 4, for those with posterior fossa tumors, and for patients with residual tumor (p < 0.05). A multivariate analysis compared variables which significantly affected survival, revealing that age is the most important factor affecting prognosis (p < 0.05), while tumor location and surgical removal do not add any significance to the effect of age on survival. We conclude that age has the strongest prognostic relevance in childhood intracranial ependymomas, while the effect of tumor location on survival may be related to the high incidence of lateral recess ependymomas in younger children.
Treatment of Posthemorrhagic Hydrocephalus in the Preterm Infant with a Ventricular Access Device
Authors: Hudgins Roger J. , Boydston William R. , Gilreath Carita L. 
Published: April 2003

Intraventricular hemorrhage (IVH) and subsequent posthemorrhagic hydrocephalus (PHH) commonly complicate the course of extremely preterm infants. Many methods for treating the hydrocephalus have been used, none of which are ideal. We present the largest series of infants with PHH treated with one modality, the ventricular access device (VAD). One hundred and forty-nine preterm infants with PHH were treated by placement of a VAD and serial taps to control intracranial pressure and ventricular size. Variables recorded include gender, race, gestational age, weight at birth, IVH grade, incidence of VAD infection, malfunction or local wound problems and indwelling time to either shunt placement or VAD removal. Of the 149 preterm infants, 91 were males and 58 females. The average birth weight was 994 g and the average gestational age at birth was 26.3 weeks. Three infants were IVH grade 1, 8 were grade 2, 62 were grade 3 and 76 were grade 4. VAD occlusion occurred in 15 infants (10%). Nine infants required contralateral VAD placement for a trapped ventricle. VAD infection occurred in 12 infants (8%), 5 of whom were treated successfully with a combination of systemic and intra-VAD antibiotics without removal of the VAD. The total rate of revision was thus 20% (15 for occlusion, 9 for trapped ventricle, 7 for infection). Wound problems were minimal and consisted of 4 cerebrospinal fluid leaks and 14 subgaleal fluid collections. For the 133 survivors, the rate of shunt placement was 88%. The VAD, while not ideal, is an excellent treatment at this time for PHH. It can be utilized for several months with acceptable rates of infection, blockage and wound complications. The VAD tap is simple to perform, not disruptive to minimal stimulation protocols, and can be done by physician extenders. In addition, medications can be administered via the access device, thus allowing treatment of some infections without VAD removal as well as instillation of thrombolytic agents such as urokinase.
Successful Use of Intracavitary Bleomycin for Low-Grade Astrocytoma Tumor Cyst
Authors: Disabato Jennifer A. , Handler Michael H. , Strain John D. , Fleitz Julie M. , Foreman Nicholas K. 
Published: April 2003

We report successful use of bleomycin in a low-grade astrocytoma tumor cyst of the tectal plate. A 6-year-old male underwent subtotal resection of a low-grade astrocytoma of the tectal plate followed by chemotherapy and proton beam radiation at age 2 and a half. Despite resolution of the solid portion of the tumor, serial MRI showed enlargement of a bilobar tumor cyst 3 years after the original diagnosis. The patient developed progressive ataxia, short-term memory loss and dysconjugate gaze. Following stereotactic placement of an Ommaya reservoir into the cyst, Isovue contrast and CT scan were used to confirm the integrity of the cyst. Five consecutive daily doses of 3.0 mg of bleomycin were instilled into the cyst after removal of cyst fluid. The therapy was well tolerated in the outpatient setting, and the clinical findings resolved. Subsequent CT and MRI at 4 months and 2 years after bleomycin confirmed no recurrence of the tumor or cyst.
Relationship between Inflammatory Cells in Bronchoalveolar Lavage Fluid and Pathologic Changes in the Lung Interstitium
Authors: Yoshii Chiharu , Nagata Nobuhiko , Tao Yoshiaki , Suematsu Rika , Nikaido Yoshihiko , Kido Masamitsu 
Published: April 2003

Bronchoalveolar lavage (BAL) is recognized as an important research tool for various lung diseases, but it is still uncertain whether inflammatory cells in BAL fluid (BALF) accurately reflect pathologic changes in the lung interstitium. We used a morphometric method to quantify the density of inflammatory cells in the lung interstitium by utilizing a computer-aided graphic analyzer and compared those findings with BALF results. Two types of animal models were studied, i.e., endotoxemia (<i>Escherichia coli</i> endotoxin) and hypersensitivity pneumonitis (inhaled ovalbumin). Male Wistar rats were used; the right lungs were lavaged and the left lungs were prepared for morphometric study. In the endotoxemia model, the neutrophil fraction in BALF and the neutrophil density in the lung interstitium correlated significantly at 18 h (r = 0.81, p < 0.05) and 24 h (r = 0.81, p < 0.05) but not at any other time points after injection. In the hypersensitivity pneumonitis model, the neutrophil fraction in BALF and the neutrophil density in the lung interstitium correlated significantly (r = 0.80, p < 0.05) only at 3 h after inhalation. The lymphocyte fraction in BALF and the lymphocyte density in the lung interstitium were correlated positively at 3 h (r = 0.83, p < 0.05), 1 day (r = 0.82, p < 0.05), 2 days (r = 0.67, p = NS), and 4 days (r = 0.87, p < 0.05), but not at 6 days after inhalation. Our data suggest that neutrophil fraction in BALF does not reflect neutrophil populations in the lung interstitium except at the time of maximal neutrophil count in lung lavage. For lymphocytes in the hypersensitivity pneumonitis model, those in BALF and in the lung interstitium roughly correlate in the majority of measurements.
Clearance in Small Ciliated Airways in Allergic Asthmatics after Bronchial Allergen Provocation
Authors: Svartengren Katharina , Svartengren Magnus , Philipson Klas , Barck Charlotte , Bylin Gunnar , Camner Per 
Published: April 2003

<i>Background:</i> Asthma tends to affect mucociliary clearance, as assessed from measurements in large airways. However, there is no knowledge about clearance in the smallest airways of the tracheobronchial region in acute exacerbation of asthma. <i>Objective:</i> The aim of the study was to investigate clearance from the bronchiolar region in patients with allergic asthma in a situation resembling a mild acute exacerbation of the disease. We also aimed to compare clearance data with corresponding data found for healthy subjects and asthmatics on therapy. <i>Methods:</i> Tracheobronchial clearance was studied twice in 9 patients with mild asthma of the allergic type after inhalation of 6 μm (aerodynamic diameter) monodisperse Teflon particles labelled with <sup>111</sup>In. At one exposure, inhalation was performed 4 h after bronchial provocation with an allergen the patients were allergic to. The second exposure was a control measurement. The particles were inhaled at an extremely slow flow, 0.05 liter/s, which gives deposition mainly in the small ciliated airways (bronchioles). Lung retention was measured at 0, 24, 48 and 72 h. <i>Results:</i> All patients demonstrated an early asthmatic reaction of varying degree after bronchial provocation. There was significant clearance of radioaerosol in each 24-hour period for both exposures, with the possible exception of the period between 24 and 48 h for the provocation exposure, with similar fractions of retained particles at all points of time. The retained fractions were significantly larger compared to a group of healthy subjects and asthmatics on regular treatment with anti-inflammatory drugs. <i>Conclusions:</i> Our results indicate that in allergic asthmatics a bronchial allergen provocation with an early asthmatic reaction does not significantly influence overall clearance from the bronchiolar region. However, in the present group of patients, retention in small ciliated airways was significantly higher compared to healthy subjects and asthmatics on regular treatment.
Reproterol – A Monomolecular Combination of Orciprenaline and Theophylline: Novel Aspects of Its Mode of Action in Asthma
Authors: Juergens Uwe R. , Stöber Meinolf , Vetter Hans 
Published: April 2003

<i>Background and Objective:</i> Reproterol is a monomolecular combination of orciprenaline and theophylline used as β-adrenergic agonist to induce bronchodilation in bronchial asthma. Since the mechanism of action of reproterol has not been investigated so far, its potential anti-inflammatory activity in asthma remains still unknown. Therefore, we have studied in vitro whether the theophylline component of the reproterol molecule might enhance the stimulatory effect of the β-adrenoceptor on cAMP production resulting in suppression of inflammatory mediator production. <i>Methods:</i> The effects of reproterol, orciprenaline and theophylline (10<sup>–9</sup>–10<sup>–5</sup> <i>M</i>) on spontaneous cAMP (5 × 10<sup>4</sup> cells/30 min)- and on LPS (10 μg/ml)-stimulated LTB<sub>4</sub> production (10<sup>5</sup> cells/4 h) were determined in normal monocytes in vitro. <i>Results:</i> Production of cAMP (n = 9) was significantly augmented in a dose-dependent manner by orciprenaline (30 ± 8%) and theophylline (28 ± 10%), but mostly by reproterol (127 ± 8%) at 10<sup>–5</sup> <i>M</i>. Despite incubation with propranolol, significant stimulation of cAMP production was notable following reproterol therapy. Production of LTB<sub>4</sub> was significantly inhibited by reproterol (–48 ± 14%) and less by theophylline (–28 ± 10%), but was stimulated by orciprenaline (+20 ± 8%) at 10<sup>–5</sup> <i>M</i>. <i>Conclusion:</i> We conclude that reproterol exerts a strong stimulatory effect on monocyte cAMP production and a suppressive effect on LTB<sub>4</sub> production possibly due to a synergistic mode of action on adenylate cyclase activity and inhibition of phosphodiesterases. More clinical studies in bronchial asthma will be needed to determine whether these results may translate into clinically relevant effects.
Stereotactic Biopsy of Intracranial Brain Lesions
Authors: Fritsch, Michael J. , Leber, Mark  J. , Gossett, Lynne , Lulu, Bruce A. , Hamilton Allan J. 
Published: April 2003

Diagnostic yield and complication rate were analyzed for a series of 65 consecutive stereotactic biopsies of intra-axial brain lesions. The diagnostic yield was 98.5 ± 1.5% and the complication rate was 1.5%. A median number of 14 biopsies (range 1–48) were taken per lesion. The biopsy sites followed a clockwise pattern, going from the superficial margin to the center and the deep margin of the lesion with respect to the inner table of the skull. A side window cannula biopsy needle was used. All patients underwent immediate postoperative CT scans within 4 h of biopsy to rule out intracranial complications. All patients were discharged within 24 h after biopsy, unless medical reasons unrelated to the biopsy required further hospitalization. We attribute the high diagnostic yield in our series to the high number of systematically taken biopsies per lesion. The higher number of biopsies did not lead to an increase in complications. From our experience, it appears safe to discharge patients the same day or within 24 h after a stereotactic biopsy if the postoperative CT shows no complication. Stereotactic biopsy could often safely be performed on an outpatient basis.
Frameless Laser-Guided Stereotaxis: A System for CT-Monitored Neurosurgical Interventions
Authors: Hussman Karl L. , Chaloupka John C. , Berger Scott B. , Chon Kenneth S. , Broderick Maggie 
Published: April 2003

<b>Objective:</b> Since a simple, rapid and accurate stereotactic system allowing CT monitoring would offer the neurosurgeon several advantages, the feasibility and application accuracy of frameless laser-guided freehand point stereotaxis for neurosurgical interventions was studied. <b>Methods:</b> A Cartesian coordinate grid mounted upon the far wall of a CT scan room defined a plane. The scanner isocenter defined the origin of a three-dimensional coordinate system. Phantom entry point and target point coordinates were determined by the positional CT cursor. These coordinates were entered into a computer which determined the coordinates of the grid intersection point with a line passing through the entry and target points. A tripod-mounted laser assembly comprising two encased lasers oriented retrograde and antegrade along opposite vectors, was positioned near the grid. The retrograde laser was positioned to illuminate the marked grid intersection point while the antegrade laser simultaneously illuminated the entry point; the beams were thereby aligned along the line of trajectory. The tip of a probe was placed on the entry point; the hub was then moved into the path of the antegrade laser, thereby aligning the probe with the line of trajectory. The probe was then inserted to the target at a trigonometrically calculated distance. <b>Results:</b> Ten consecutive phantom tests averaged 17.5 min. Phantom test application accuracy averaged ±2 mm at an average insertion distance of 7.1 cm. <b>Conclusion:</b> Phantom tests indicate that simple, rapid and accurate CT-monitored frameless laser-guided freehand point stereotaxis is feasible. Clinical investigation is warranted.
Comparative Magnetic Resonance Image-Based Evaluation of Thalamotomy and Pallidotomy Lesion Volumes
Authors: Tollefson Travis T. , Burns Jeffrey , Wilkinson Steve , Overman John , Kieltyka Jennifer , Goodman Scott H. , Koller William C. , Tröster Alex , Lyons Kelly , Pahwa Rajesh , Batnitzky Solomon , Wetzel Louis , Gordon Michael 
Published: April 2003

Acute thalamotomy and pallidotomy lesion volumes based on magnetic resonance (MR) images were measured in 22 patients (11 thalamotomy and 11 pallidotomy patients). Thalamotomy inner lesion volumes (0.06 ± 0.04 ml; thermocoagulative zone) were smaller than pallidotomy inner lesion volumes (0.14 ± 0.08 ml) as determined using T<sub>1</sub>-weighted 3D-MPRAGE (1.5-mm slice spacing). Similar results were found using T<sub>1</sub>-weighted (6-mm slice spacing) image sets (0.09 ± 0.05 ml, thalamotomy; 0.13 ± 0.05 ml, pallidotomy). No differences were found when comparing thalamic or pallidal inner lesion volumes when the comparison was based on T<sub>2</sub> weighted images. Thalamotomy total lesion volumes (thermocoagulative and surrounding edematous zones) were less than pallidotomy total lesion volumes independent of the MR protocol. The difference in thalamotomy and pallidotomy lesion volumes is most likely based on the distance between each discrete lesion placed along the lesioning tracts. In 7 of 11 thalamotomies, this distance was 1 mm with the remaining having 2 mm between each discrete lesion. All pallidotomy discrete lesions were 2 mm apart. More overlap between discrete lesioning sites for thalamotomies is likely to produce reduced lesion volumes.
Temperature Distribution Produced in Brain Tissue and Other Media by a Radiofrequency Hyperthermia Generator
Authors: Chua Eric , Gose Earl , Vinas Federico C. , Dujovny Manuel , Star Jeniffer 
Published: April 2003

The temperature distribution produced in living brain tissue by a radiofrequency, Neuro N-50, hyperthermia probe was measured as a function of probe temperature, heating duration, and distance from the heating probe by a sensor containing five thermocouples for durations up to 2 min. Brain sections were examined to determine the effects of heating at various temperatures. It was found that a simple theoretical conductive heat transfer model predicted the steady-state temperature distributions quite well. At distances up to 7.4 mm from the heating probe, a heating time of 20 s was sufficient to produce about 90% of the temperature rise measured at 120 s. The equilibrium temperature at any distance from the center of the probe was a linear function of the reciprocal of this distance. The time constant for heating was approximately 3 s at 0.95 mm from the heating probe and about 10 s at 7.4 mm for brain tissue, while these values are about 5–20 s in egg white. For a given probe size, higher probe temperatures increased the size of the region of cell death. According to the heat transfer model, the diameter of the region of tissue that attains a given temperature is proportional to the diameter of the probe. The use of probe temperatures up to 90°C would enable an increase in the volume of the region of cell death, or the use of a smaller diameter probe to produce a lesion of a given size.