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Biomedical subjects

J Sheehan

Publications and source records attributed to J Sheehan.

At least 37 records · Page 2Linked to original sources
PubMed1999

Process Design and Costing of Bioethanol Technology: A Tool for Determining the Status and Direction of Research and Development.

Bioethanol is a fuel-grade ethanol made from trees, grasses, and waste materials. It represents a sustainable substitute for gasoline in today's passenger cars. Modeling and design of processes for making bioethanol are critical tools used in the U.S. Department of Energy's bioethanol research and development program. We use such analysis to guide new directions for research and to help us understand the level at which and the time when bioethanol will achieve commercial success. This paper provides an update on our latest estimates for current and projected costs of bioethanol. These estimates are the result of very sophisticated modeling and costing efforts undertaken in the program over the past few years. Bioethanol could cost anywhere from $1.16 to $1.44 per gallon, depending on the technology and the availability of low cost feedstocks for conversion to ethanol. While this cost range opens the door to fuel blending opportunities, in which ethanol can be used, for example, to improve the octane rating of gasoline, it is not currently competitive with gasoline as a bulk fuel. Research strategies and goals described in this paper have been translated into cost savings for ethanol. Our analysis of these goals shows that the cost of ethanol could drop by 40 cents per gallon over the next ten years by taking advantage of exciting new tools in biotechnology that will improve yield and performance in the conversion process.

Journal Article↗
PubMed1999

Enzymes, Energy, and the Environment: A Strategic Perspective on the U.S. Department of Energy's Research and Development Activities for Bioethanol.

For well over one hundred years, researchers around the world have pursued ways to make ethanol from biomass such as wood, grasses, and waste materials. To distinguish it from ethanol made from starch and sugars in traditional agricultural crops, we refer to ethanol made from biomass as "bioethanol." The effort to develop bioethanol technology gained significant momentum in the late 1970s as a result of the energy crises that occurred in that decade. This article briefly reviews the broader history of bioethanol technology development. With this as a background, we focus our attention on the strategic thinking behind the U.S. Department of Energy's Bioethanol Program, which envisions remarkable advances in cellulase enzyme research and as the basis for significant future process cost reductions.

Journal Article↗
PubMed1999

How to defuse compliance time bombs. Part 2: Six hypothetical allegations. Panel discussion.

In the second and final part of this series, a panel of legal experts discusses more hypothetical allegations against a fictional laboratory, including billing for additional indices, using expired reagents, and falsifying the results of employee competency tests. Learn how to handle these dilemmas before they explode into full-blown legal violations.

Clinical Laboratory Techniques↗
PubMed1998

Surreptitious observation of responses to hypnotically suggested hallucinations: a test of the compliance hypothesis.

Suggestions for arm levitation and for visual, auditory, tactile, and taste hallucinations were administered twice via audiotape to a group of high suggestible students and low suggestible simulators. During one of the administrations, participants were led to believe they were alone, but their behavior was surreptitiously recorded on videotape and observed on a video monitor. During the other administration, they were observed openly by an experimenter who had not been informed about group assignment. When unaware that they were being observed, simulators were significantly less responsive to suggestion and engaged in substantially more role-inappropriate behavior. In contrast, the responsiveness of nonsimulating students was not affected by the presence of an experimenter, and they exhibited little role-inappropriate behavior even when alone. These data indicate that the responses of suggestible individuals reflect internally generated changes in experience and are not due to simple intentional compliance (i.e., faking).

Adult↗
PubMed1998

Formation and turnover of NSF- and SNAP-containing "fusion" complexes occur on undocked, clathrin-coated vesicle-derived membranes.

Specificity of vesicular transport is determined by pair-wise interaction between receptors (SNAP receptors or SNAREs) associated with a transport vesicle and its target membrane. Two additional factors, N-ethylmaleimide-sensitive fusion protein (NSF) and soluble NSF attachment protein (SNAP) are ubiquitous components of vesicular transport pathways. However, the precise role they play is not known. On the basis that NSF and SNAP can be recruited to preformed SNARE complexes, it has been proposed that NSF- and SNAP-containing complexes are formed after SNARE-dependent docking of transport vesicles. This would enable ATPase-dependent complex disassembly to be coupled directly to membrane fusion. Alternatively, binding and release of NSF/SNAP may occur before vesicle docking, and perhaps be involved in the activation of SNAREs. To gain more information about the point at which so-called 20S complexes form during the transport vesicle cycle, we have examined NSF/SNAP/SNARE complex turnover on clathrin-coated vesicle-derived membranes in situ. This has been achieved under conditions in which the extent of membrane docking can be precisely monitored. We demonstrate by UV-dependent cross-linking experiments, coupled to laser light-scattering analysis of membranes, that complexes containing NSF, SNAP, and SNAREs will form and dissociate on the surface of undocked transport vesicles.

Animals↗
PubMed1998

The role and rewards of asylum attendants in Victorian England.

This paper reports on a study of the role and rewards of asylum attendants at a West Yorkshire asylum in the period 1852-1889. The role aspect was analysed with reference to the Regulations and Orders of the institution concerned and the rewards aspects with reference to the staff records. It emerged that attendants were the most poorly paid group of staff within the institution and the drop-out rate was high in the early years of service, though a number did give long service.

Economics, Hospital↗
PubMed1997

Structural characterisation of two forms of procyclic acidic repetitive protein expressed by procyclic forms of Trypanosoma brucei.

A procyclic acidic repetitive protein (PARP) fraction was purified from long-term cultures of Trypanosoma brucei procyclic forms by a solvent-extraction and reverse phase chromatography procedure. The PARP fraction yielded small quantities of a single N-linked oligosaccharide with the structure Man alpha1-6(Man alpha1-3)Man alpha1-6(Man alpha1-3)Manbeta1-4GlcNAcbeta1-4GlcNAc (Man5GlcNAc2). Fractionation of PARP on Con A-Sepharose revealed that the majority (80 to 90%) of the PARP fraction did not bind to Con A and was composed of the parpA alpha gene product that contains repeats of -Glu-Pro-Pro-Thr- (GPEET-PARP) and that lacks an N-glycosylation site. This form of PARP has not been previously identified at the protein-level. The minor Con-A-binding fraction was shown to be rich in the previously described form of PARP, encoded by the parpAbeta and/or parpB alpha genes, that contains a -Glu-Pro- repeat domain (EP-PARP) and an N-glycosylation site. Analysis of longer and shorter-term cultures suggested that procyclic cells initially express predominantly EP-PARP that is gradually replaced by GPEET-PARP. Both forms of PARP were shown to contain indistinguishable glycosylphosphatidylinositol (GPI) membrane anchors, where the conserved GPI core structure is substituted by heterogeneous sialylated branched polylactosamine-like structures that are predicted to form a dense surface glycocalyx above which the polyanionic -Glu-Pro-Pro-Thr- and -Glu-Pro- repeat domains are displayed. The phosphatidylinositol (PI) component of the GPI anchor was shown to be a mixture of 2-O-acyl-myo-inositol-1-HPO4-(sn-1-stearoyl-2-lyso-glycerol) and 2-O-acyl-myo-inositol-1-HPO4-(sn-1-octadecyl-2-lyso-glycerol), where the acyl chain substituting the inositol ring showed considerable heterogeneity. Mass spectrometric and light scattering experiments both suggested an average mass of approximately 15 kDa for GPEET-PARP, with individual glycoforms ranging from about 12 kDa to 20 kDa, that is consistent with its amino acid and carbohydrate composition. A measured translational diffusion coefficient of 3.9 x 10(7) cm2 s(-1) indicates that this molecule has a highly elongated shape. The possible functions of these unusual glycoproteins are discussed.

Animals↗
PubMed1996

Risk of aspirin-associated major upper-gastrointestinal bleeding with enteric-coated or buffered product.

BACKGROUND: Aspirin products are known to cause irritation and injury to the gastric mucosa. The belief that enteric-coated and buffered varieties are less likely to occasion major upper-gastrointestinal bleeding (UGIB) than plain aspirin was tested in data from a multicentre case-control study. METHODS: 550 incident cases of UGIB admitted to hospital with melaena or haematemesis and confirmed by endoscopy, and 1202 controls identified from population census lists, were interviewed about use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) during the 7 days before the onset of bleeding (cases) or interview (controls). Relative risks of UGIB for each type of aspirin used regularly (at least every other day) were calculated overall, and according to dose, by multiple logistic regression, with control for age, sex, marital status, date, education, cigarette smoking, alcohol use, and use of NSAIDs. FINDINGS: The relative risks of UGIB for plain, enteric-coated, and buffered aspirin at average daily doses of 325 mg or less were 2.6, 2.7, and 3.1, respectively. At doses greater than 325 mg, the relative risk was 5.8 for plain and 7.0 for buffered aspirin; there were insufficient data to evaluate enteric-coated aspirin at this dose level. There were no important differences in risk attributable to the three aspirin forms according to bleeding site (gastric vs duodenal), or when users of NSAIDs were excluded. INTERPRETATION: Use of low doses of enteric-coated or buffered aspirin carries a three-fold increase in the risk of major UGIB. The assumption that these formulations are less harmful than plain aspirin may be mistaken.

Adolescent↗
PubMed1996

Type VI collagen is present in human and bovine vitreous.

BACKGROUND: Heterotypic (mixed) collagen fibrils that contain collagen types II, IX and V/XI have previously been identified in vitreous gel. The purpose of this study was to determine whether vitreous gel also contains type VI collagen microfibrils, as they are widely distributed in other tissues where they may play an important structural role. METHODS: Bovine and human vitreous gel was analysed by rotary shadowing electron microscopy after bacterial collagenase digestion and gel filtration chromatography. Bovine vitreous was extracted in 4 M guanidine hydrochloride, and following isopycnic centrifugation fractions were analysed by western blotting. RESULTS: Type VI collagen microfibrils were identified by electron microscopy in human and bovine vitreous. Type VI collagen was identified by western blot analysis. CONCLUSION: Type VI collagen is present in vitreous and may participate in the structural assembly of the vitreous gel.

Animals↗
PubMed1994

External examiners: roles and issues.

This paper is based on an analysis of the role of external examiners and a discussion of the various aspects of the role. Fifteen facets of the role have been identified and each facet is discussed with reference to the relevant literature. Among the issues discussed are the powers of external examiners in the decision making process; their role as the custodians of standards; and the significance of their reports. The discussion spans four levels of academic awards including diploma, bachelor's degree, master's degree and doctoral degree and deals with matters of principle as well as the mass of written and other material which external examiners are faced with. Some strengths and weaknesses of the external examining system have been identified and finally a question is raised about its future.

Education, Nursing↗
PubMed1994

A journal club as a teaching and learning strategy in nurse teacher education.

An account of the operation of a journal club in a Postgraduate Certificate in Education course for teachers of nursing is reported here. The paper is based on three issues: the background to journal clubs, the process involved in the operation of the club concerned, and the expected outcomes. The origins of journal clubs and the reading habits of nurses are considered in the background section through a review of some of the relevant literature. The negotiation involved, the frequency of meetings and the ethos in which they were conducted are discussed in the section on the processes involved. In the final section, both the tangible and personal outcomes are discussed and the conclusion reached is that a journal club is a worthwhile educational activity.

Certification↗
PubMed1993

Characterization of two different glycosylated domains from the insoluble mucin complex of rat small intestine.

The highly glycosylated domains of rat small intestinal mucins were isolated after reduction and trypsin digestion and separated into two populations (A and B) by gel chromatography. The molecular mass values were 650 and 335 kDa, respectively, and the relative yields suggest that the two glycopeptides occur in equimolar proportions. Electron microscopy revealed linear structures with weight average lengths of 230 nm (A) and 110 nm (B) corresponding to a mass/unit length of about 3 kDa/nm. The protein cores (17-19%) contain large amounts of threonine (over 40%), serine (17-24%), and proline (18-19%). Carbohydrate and sulfate account for approximately 80 and 0.5%, respectively, and gas chromatography-mass spectrometry showed that the patterns of neutral and sialic acid-containing glycans are very similar in the two glycopeptides. Both contain a significant amount (7-10 mol %) of single GalNAc residues, the average oligosaccharide is about 4 sugar residues long, and the largest species observed are heptasaccharides. The major neutral and sialic acid-containing oligosaccharides are Fuc1-2Gal1-3GalNAcol and GlcNAc1-6(NeuGc2-Gal1-3)GalNAcol, respectively. Sialic acid is present as both N-acetyl- and N-glycoloyl-neuraminic acid. Repeated extractions of the tissue with guanidinium chloride left approximately 80% of the mucus glycoproteins as an insoluble glycoprotein complex whereas exposure to dithiothreitol or high speed homogenization accomplished complete solubilization. The "subunits" obtained after reduction with dithiothreitol are larger than glycopeptides A and B, and fragments corresponding in size to the latter are obtained after cleavage with trypsin. Most of the mucins from rat small intestine thus occurs as an insoluble glycoprotein complex composed of subunits joined with disulfide bonds. The subunits contain two highly glycosylated regions with different lengths substituted with very similar oligosaccharides.

Amino Acids↗
PubMed1993

Altered glycosylation of the MUC-1 protein core contributes to the colon carcinoma-associated increase of mucin-bound sialyl-Lewis(x) expression.

The mucin carbohydrate epitope sialyl-Le(x), detected with the monoclonal antibody AM-3, is strongly overexpressed in > 90% of human colon carcinomas. We show here that in colon carcinoma one of the mucin cores bearing the sialyl-Le(x) group is MUC-1, whereas sialyl-Le(x) present in normal colon is not detectable on MUC-1. The amounts of MUC-1 core detectable with the monoclonal antibody BC3 in extracts of tumor tissue are 60-180% of those in normal tissue. Two other carbohydrate epitopes located on MUC-1 in mucins from normal and tumor tissue have also been characterized. In contrast to sialyl-Le(x), their expression on MUC-1 is variable and does not correlate with the malignant transformation of colonic mucosa. The transfer of the sialyl-Le(x) group onto the MUC-1 core contributes to the colon carcinoma-associated overexpression of the sialyl-Le(x) epitope.

Antigens↗
PubMed1993

Issues in the supervision of postgraduate research students in nursing.

Some general points are made in this paper about the nature of postgraduate research degrees, and the process which results in a thesis is set out. These are followed by considering the degrees in a nursing context and also in relation to the social sciences. Next the aims of postgraduate research degree programmes are considered. Approaches to the matching of students are set out. Among those discussed are mentoring, collegiality, classification and framing, and the use of workshops. In the conclusion, some desired outcomes of the supervisory process are suggested.

Education, Nursing, Graduate↗
PubMed1991

Increased number of accessible sugar epitopes defined with monoclonal antibody AM-3 on colonic mucins is associated with malignant transformation of colonic mucosa.

Monoclonal antibody AM-3 detects a mucin sugar epitope (AM-3 epitope) the expression of which increases in the course of human colon carcinogenesis parallel to the gradual morphological alterations (so called adenoma-carcinoma sequence). In the present report the AM-3-positive mucin has been purified from human normal and carcinomatous colonic tissue. About 300-fold enrichment of the epitope per protein from both sources was achieved after ultracentrifugation, gel filtration on Sepharose CL-6B and isopyknic gradient centrifugation. Slot-blot and enzyme-linked immunosorbent assays of the purified preparation indicated not only different amounts of the mucins but also a consistent qualitative difference between the molecules from both sources. The qualitative difference could be obliterated by a partial removal of the AM-3 epitope from the tumor-derived mucin with neuraminidase. The visualization of the molecules by rotary shadowing indicated that the mucins from both sources have similar length distribution, 80% of the molecules being 100-600 nm long. The reaction with AM-3 antibody followed by rotary shadowing showed that in the purified preparations more than 95% of the tumor-derived molecules and 74% of the normal colon tissue-derived molecules carried the epitope. The tumor-derived mucins bound, on the average, 34 +/- 15 (SD) antibodies/1000 nm of the protein core while the mucin from normal colon tissue carried 12 +/- 11 antibodies/1000 nm of the protein core. These data indicate that the increased expression of AM-3 epitopes during malignant transformation of the human colon is due to accumulation of AM-3-positive mucin as well as a higher number of accessible AM-3 epitopes on this mucin.

Antibodies, Monoclonal↗
PubMed1991

Conceptions of the nursing process amongst nurse teachers and clinical nurses.

This is a report of an empirical study whose aim was to investigate the conceptual nature of the nursing-process approach to the delivery of nursing care. The report includes a selective review of the literature on the subject to determine how the nursing-process approach is characterized by people who write about it. Details of the grounded theory research methodology used are outlined. So are the hierarchically focused interviews used to collect the data. Details of the data analysis are also given, including the use of a cluster analysis technique. In the results section, areas of concordance between conceptions of the nursing-process approach as they appear in the literature and those held by the interviews have been identified. Areas where conceptions are at variance with those in the literature have also been identified.

Adult↗