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Biomedical subjects

J S Logan

Publications and source records attributed to J S Logan.

At least 73 records · Page 4Linked to original sources
PubMed1991

Training Japanese listeners to identify English /r/ and /l/: a first report.

Native speakers of Japanese learning English generally have difficulty differentiating the phonemes /r/ and /l/, even after years of experience with English. Previous research that attempted to train Japanese listeners to distinguish this contrast using synthetic stimuli reported little success, especially when transfer to natural tokens containing /r/ and /l/ was tested. In the present study, a different training procedure that emphasized variability among stimulus tokens was used. Japanese subjects were trained in a minimal pair identification paradigm using multiple natural exemplars contrasting /r/ and /l/ from a variety of phonetic environments as stimuli. A pretest-posttest design containing natural tokens was used to assess the effects of training. Results from six subjects showed that the new procedure was more robust than earlier training techniques. Small but reliable differences in performance were obtained between pretest and posttest scores. The results demonstrate the importance of stimulus variability and task-related factors in training nonnative speakers to perceive novel phonetic contrasts that are not distinctive in their native language.

Adult↗
PubMed1990

Identification of the origin of the growth hormone-binding protein in rat serum.

GH specifically interacts with a soluble binding protein in serum. The GH-binding protein (GHBP) has been shown to contain the extracellular portion of the cell surface GH receptor (GHR). In rats and mice there is a unique mRNA that encodes the GHBP. This mRNA contains an alternatively spliced exon that replaces the transmembrane and intracellular domains of the receptor with a short hydrophilic carboxy-terminus of 17 and 25 amino acids, respectively, in rats and mice. In humans and other species no mRNAs encoding the GHBP have been identified, suggesting that the GHBP is in these cases a proteolytically processed GHR. In this study a monoclonal antibody (GHBP 4.3) was raised to the rat GHBP using as immunogen a synthetic peptide containing the unique C-terminal 17 amino acids that are not found in the rat GHR. As predicted, this antibody is specific to rat GHBP and does not cross-react with rat GHR. In combination with polyclonal and monoclonal antibodies that recognize both GHBP and GHR, this antibody was used to show that all, or most, of the GHBP in rat serum is indeed derived from the alternatively spliced GHBP mRNA and not from proteolytic processing of the GHR. In addition, endogenous rat serum GHBP was found to exist in two forms, with apparent mol wt of 52 and 44 kDa, arising from a single protein core of 32 kDa by extensive glycosylation. The concentrations of GHBP in male and female rat plasma were also estimated to be 300 and 575 ng/ml, respectively (measured in nonglycosylated GHBP equivalents).

Amino Acid Sequence↗
PubMed1990

Medical impact analysis for the space station.

Since the Space Station Health Maintenance Facility can house only a relatively limited quantity of supplies and equipment, the decisions about what should be included must be based on documented research. In this study, Space Station medical care priorities were determined by a medical impact analysis of two analog populations, U.S. Army and U.S. Navy personnel. Diseases and injuries in the International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM) were ranked, using a Medical Impact Score (MIS) combining modified incidence rate and a function of disease outcome. The validity of the analysis method was tested by measuring rank order correlation between the two analog populations. Despite virtually identical age and sex distributions, Army and Navy incidence rates differed significantly for half of the ICD-9-CM categories, p less than 0.05. Disability rates differed for 76%, p less than 0.05. Nevertheless, Army and Navy MIS rank orders for categories and sections were not significantly different, p less than 0.001. In critical ways, the Space Station will be a safer environment than Earth. Cardiac events, musculoskeletal injuries, affective psychoses, and renal calculi were among the highest scoring categories.

Accidents, Occupational↗
PubMed1989

The role of smart medical systems in the Space Station.

NASA is developing a Health Maintenance Facility to provide medical equipment and supplies requisite for the Space Station to be launched in the late 1990s. An essential component of this medical facility is a computerized Medical Decision Support System which will expedite medical officers' efforts to maintain the crew's health. The computerized system includes four major functions: 1. A data collection and storage system with a self-contained medical expert scheme for performing treatment protocols. The expert system has 'data driven' and 'time driven' capabilities to facilitate automatic decision-making functions. 2. An integrated medical record and medical 'reference' information management component. 3. An inventory management system for medical supplies and pharmaceuticals. 4. Video, audio, and data communications between the medical officer in the Space Station and ground-based medical personnel. This paper discusses the design of such computerized data collection, communications and expert medical systems as will be developed for use in a Space Station Health Maintenance Facility.

Aerospace Medicine↗
PubMed1989

The growth hormone-binding protein in rat serum is an alternatively spliced form of the rat growth hormone receptor.

A cDNA clone isolated from rat liver was demonstrated to encode a soluble, secreted growth hormone (GH)-binding protein consistent with the properties of the newly discovered serum GH-binding protein. The protein coding region of this cDNA was identical in sequence to the extracellular domain of the rat liver GH receptor up to three amino acids before the putative transmembrane domain. At this point, an additional 17 amino acids were encoded in the GH-binding protein before a stop codon was encountered. This cDNA clone was shown to be representative of the structure of the mRNA present in rat liver. These results suggest that the mechanism for production of the rat serum GH-binding protein is by alternative splicing of the gene for the rat GH receptor.

Amino Acid Sequence↗
PubMed1989

Segmental intelligibility of synthetic speech produced by rule.

This paper reports the results of an investigation that employed the modified rhyme test (MRT) to measure the segmental intelligibility of synthetic speech generated automatically by rule. Synthetic speech produced by ten text-to-speech systems was studied and compared to natural speech. A variation of the standard MRT was also used to study the effects of response set size on perceptual confusions. Results indicated that the segmental intelligibility scores formed a continuum. Several systems displayed very high levels of performance that were close to or equal to scores obtained with natural speech; other systems displayed substantially worse performance compared to natural speech. The overall performance of the best system, DECtalk--Paul, was equivalent to the data obtained with natural speech for consonants in syllable-initial position. The findings from this study are discussed in terms of the use of a set of standardized procedures for measuring intelligibility of synthetic speech under controlled laboratory conditions. Recent work investigating the perception of synthetic speech under more severe conditions in which greater demands are made on the listener's processing resources is also considered. The wide range of intelligibility scores obtained in the present study demonstrates important differences in perception and suggests that not all synthetic speech is perceptually equivalent to the listener.

Adult↗
PubMed1989

Trench fever in Belfast, and the nature of the 'relapsing fevers' in the United Kingdom in the nineteenth century.

Some evidence is assembled to suggest that trench fever, an infection with a strain of Rochalimaea, if not quintana, then vinsonii, was present in Belfast in the first half of the nineteenth century in endemic and epidemic form. It may have amounted at times to one half or more of 'fever'. This may account for the comparatively low mortality in some years from 'fever'. The phrase 'relapsing fever' in the nineteenth and twentieth century medical literature of the United Kingdom should not be taken necessarily to mean infection with Borrelia recurrentis. Much or most may have been infection with Rochalimaea, quintana or vinsonii. The newly discovered Irish vole should be examined to see if it carries a Rickettsia or Rochalimaea infection.

Animals↗
PubMed1983

Cardiac function monitored by impedance cardiography during changing seatback angles and anti-G suit inflation.

Impedance cardiography (IC) appears to be a promising noninvasive technique for monitoring small changes in pilot cardiovascular status during conditions simulating flight. Heart rate (HR), stroke volume (SV), cardiac output (CO), ventricular ejection time (VET), and thoracic impedance (Zo) were monitored in ten volunteers for 5 min at each of four seatback angles from vertical: 12 degrees, 30 degrees, 45 degrees, and 60 degrees. Data were also obtained at three seatback angles (12 degrees, 30 degrees, 60 degrees) for 6 min each before, during, and after inflation of the standard USAF anti-G suit to 1.5 psi. Significant differences (p less than 0.05) in HR, SV, CO, VET and Zo were observed among the four positions. Inflation of the standard anti-G suit to 1.5 psi at 1.0 +Gz did not significantly alter HR, SV, or CO; whereas, 1 min of deflation of the anti-G suit significantly altered HR, SV, CO compared to inflation values. The results suggest IC can detect small differences in HR, SV, CO, VET, and Zo within subjects as a function of minor changes in body position.

Cardiac Output↗
PubMed1979

HLA antigen frequencies in flax byssinosis patients.

Not all workers exposed to flax dust contract byssinosis. It is not known what determines susceptibility or insusceptibility. This study is an attempt to establish whether the incidence of histocompatibility antigens is involved in susceptibility to the disease. Forty patients suffering from flax byssinosis were tissue-typed for HLA-A and -B antigens. HLA-B27 was significantly more common in the patients (22.5%) than in the controls (5.5%); P = 0.029 after correction for the number of antigens compared. HLA-A11 was present in twelve patients (30%) compared with 14% in the controls; after correction for the number of comparisons, this is not a statistically significant increase. Because HLA-B27, though significantly more common in flax byssinosis, is not necessary for its occurrence (77.5% of our patients did not have it), it is possible that the increase in the frequency of HLA-B27 is attributable to an association with other genes, perhaps those regulating the immune response or coding for antigens at other HLA loci.

Adult↗
PubMed1978

HLA-antigen frequencies in patients with a Plummer-Vinson stricture.

Factors of individual susceptibility seem to be involved in the occurrence of Plummer-Vinson stricture, which is a permanent stricture of the cervical esophagus associated with long continued iron deficiency. Fifty female patients with Plummer-Vinson stricture were HLA typed and the antigen frequencies were compared with those of 75 female blood donors from the same geographic area and of the same race. A comparison was also made with the HLA antigen frequencies of a group of 200 blood donors (75 female and 125 male). There were no statistically significant differences in the HLA antigen distributions of the three groups.

Adult↗