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Guile SD, Bantick JR, Cheshire DR, Cooper ME, Davis AM, Donald DK, Evans R, Eyssade C, Ferguson DD, Hill S, Hutchinson R, Ingall AH, Kingston LP, Martin I, Martin BP, Mohammed RT, Murray C, Perry MWD, Reynolds RH, Thorne PV, Wilkinson DJ, Withnall J. Potent blockers of the monocarboxylate transporter MCT1: novel immunomodulatory compounds. Bioorg Med Chem Lett 2006; 16:2260-5. [PMID: 16455256 DOI: 10.1016/j.bmcl.2006.01.024] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 01/05/2006] [Accepted: 01/06/2006] [Indexed: 11/24/2022]
Abstract
A novel series of potent blockers of the monocarboxylate transporter, MCT1, is disclosed. From very potent but lipophilic lead compounds, systematic changes to all parts of the molecule, targeting reduction in log D, afforded compounds with significantly improved overall properties. These compounds show potent immunomodulatory activity.
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Abstract
Sensitization to indoor allergens has long been recognized as a risk factor for asthma and its associated phenotypes. Immunoglobulin E antibody quantification may be used to confirm that a particular sensitization has a role in the development of respiratory symptoms. However, in order to use quantitative information effectively, it is essential to understand the factors that contribute to the deterioration of symptoms and cause exacerbations. One such risk factor is high allergen exposure. Worsening asthma control is also associated with virus infections, in particular rhinovirus infection. Each of these factors in isolation is unlikely to have a major effect on symptoms. However, the combination of respiratory virus infection, allergen sensitization and concurrent high exposure to allergens markedly increases the risk for hospitalization. Further investigation of this synergism could help to understand the mechanisms of asthma exacerbations and lead to the development of strategies for prevention.
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Murray C, Golombok S. Solo mothers and their donor insemination infants: follow-up at age 2 years. Hum Reprod 2005; 20:1655-60. [PMID: 15734751 DOI: 10.1093/humrep/deh823] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Findings are presented of the second phase of a longitudinal study of solo-mother families created through donor insemination (DI). METHODS At the time of the child's second birthday, 21 solo DI mother families were compared with 46 married DI families on standardized interview and questionnaire measures of the psychological well being of the mothers, mother-child relationships and the psychological development of the child. RESULTS The solo DI mothers showed greater pleasure in their child and lower levels of anger accompanied by a perception of their child as less 'clingy'. Fewer emotional and behavioural difficulties were shown by children of solo than married DI mothers. CONCLUSIONS The findings from this first cohort of solo DI families to be studied lend further weight to the view that these women represent a distinct subgroup of single parents, who, out of a strong desire for a child, have made the active choice to go it alone. Moreover, this route to parenthood does not necessarily seem to have an adverse effect on mothers' parenting ability or the psychological adjustment of the child.
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Golombok S, Jadva V, Lycett E, Murray C, Maccallum F. Families created by gamete donation: follow-up at age 2. Hum Reprod 2005; 20:286-93. [PMID: 15539442 DOI: 10.1093/humrep/deh585] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Findings are presented of the second phase of a longitudinal study of families created through gamete donation. METHODS At the time of the child's second birthday, 46 donor insemination families and 48 egg donation families were compared with 68 natural conception families on standardized interview and questionnaire measures of the psychological well being of the parents, parent-child relationships and the psychological development of the child. RESULTS The gamete donation mothers showed a trend towards greater pleasure in their child accompanied by a perception of their child as more vulnerable, with egg donation mothers tending towards greater pleasure and donor insemination mothers tending towards greater concern. The fathers did not differ on any of the variables under study. CONCLUSIONS The findings from this recent cohort add further weight to the growing body of research showing that the absence of a genetic link between a parent and a child does not necessarily jeopardize the development of a positive relationship between them.
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Canfell K, Gray W, Snijders P, Murray C, Tipper S, Drinkwater K, Beral V. Factors predicting successful DNA recovery from archival cervical smear samples. Cytopathology 2004; 15:276-82. [PMID: 15456416 DOI: 10.1111/j.1365-2303.2004.00164.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polymerase chain reaction (PCR)-based DNA testing of archival cervical smear slides is a useful method of retrospectively establishing the presence of the human papillomavirus (HPV) in cervical cells. A cellular DNA recovery test is performed in parallel to HPV DNA testing to ensure that sufficient cells are present and purification of sample DNA has been successfully performed. Previous studies have not comprehensively assessed DNA recovery rates in slides older than 13 years. We undertook a study to determine the factors impacting DNA recovery in 436 UK slides dating from 11 to 33 years prior to testing. Overall, a low cellular DNA recovery success rate of 29% was obtained but a strong trend was observed with increasing recovery rates the older the slides (P < 0.001). Recovery rates increased from 22% in the most recent slides collected from 1988 to 1992, to 61% in the oldest slides, collected in 1970-72. It is likely that fixation compounds incorporating acetic acid, introduced in the UK through the 1980s, have compromised subsequent attempts at PCR amplification. These findings emphasize the importance of the original fixation method in the success of DNA recovery from archival smear samples.
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van Santen VL, Joiner KS, Murray C, Petrenko N, Hoerr FJ, Toro H. Pathogenesis of Chicken Anemia Virus: Comparison of the Oral and the Intramuscular Routes of Infection. Avian Dis 2004; 48:494-504. [PMID: 15529971 DOI: 10.1637/7155-010904r] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The events during the pathogenesis of chicken anemia virus (CAV) infection following intramuscular (IM) and oral inoculation were further elucidated and compared by sequential clinical, pathologic, and morphometric histopathologic evaluations, and by sequential determination of CAV genome concentrations in different organs. Specific-pathogen-free chickens were inoculated by IM or oral routes with the same dose (2 x 10(6) mean tissue culture infective dose [TCID50]) of CAV isolate 03-4876 at 1 day of age. Weights and hematocrits were obtained at 7, 10, 14, 18, 21, 25, and 28 days postinoculation (DPI). Seven birds from each group were necropsied at 7, 10, 14, and 28 DPI, and samples of thymus, Harderian gland, and cecal tonsils (CT) were obtained for histopathologic examination and CAV genome quantification by real-time polymerase chain reaction. Peak CAV genome concentrations were detected in the thymus at 10 and 14 DPI in the IM and orally infected chickens, respectively. High CAV DNA concentrations were maintained throughout the experimental period until 28 DPI, despite specific seroconversion occurring by 14 DPI in the IM-inoculated chickens. CAV was isolated from both orally and IM-infected chickens 28 DPI. Peak CAV genomes in the thymuses of IM and orally infected chickens coincided with peak lymphocyte depletion in these organs. Lymphocyte repopulation of the thymus occurred by 28 DPI in spite of the presence of the virus in the organs of both infected chicken groups. CAV genomes were detected in the CT, but histopathologic changes were not observed. Compared with the IM route of infection, orally infected chickens did not show apparent signs of illness. Clinical parameters, including reduction of weight gains and hematocrits, and gross and histopathologic changes were delayed and less severe in the orally inoculated chickens. This was concurrent with a delay in accumulation of CAV genomes in the thymus of these chickens.
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Atkinson MJ, Allen RP, DuChane J, Murray C, Kushida C, Roth T. Validation of the Restless Legs Syndrome Quality of Life Instrument (RLS-QLI): findings of a consortium of national experts and the RLS Foundation. Qual Life Res 2004; 13:679-93. [PMID: 15130030 DOI: 10.1023/b:qure.0000021322.22011.d0] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
UNLABELLED This study was designed to assess the initial psychometric properties of a new disease-specific health-related quality of life (HRQL) measure, the Restless Legs Syndrome (RLS) Quality of Life Instrument (RLS-QLI). METHODS Draft items were generated from a literature review, consultation with MD and PhD specialists in the fields of neurology and sleep medicine, and input from two patient focus groups. The initial item reduction was accomplished using a survey of 392 persons with self-reported RLS symptoms from the membership of the RLS Foundation. The final (independent) validation sample consisted of 574 of persons on the RLS Foundation's Interest Group List Serve who also reported having RLS. The mean age of participants was 54.5 (SD 12.3), with a sex ratio of 1M:2F, and the majority was on some form of medication for RLS (66%). RESULTS Four factors were identified (Daily Function, Social Function, Sleep Quality, and Emotional Well-Being) consisting of 17 items that explained 73.3% of the total variance. Each scale had good internal consistency (Cronbach's alpha's between 0.85 and 0.91) and 2-week test retest stability (Pearson Correlations between 0.81 and 0.93). Convergent validity was demonstrated using related scales on the SF-36 (r = 0.47-0.60) and criterion-related validity was shown using the clinical IRLS Scale of Symptom Severity (r = -0.45 to -0.77). CONCLUSION The RLS-QLI is a valid disease-specific HRQL instrument that will contribute to our understanding of how RLS impacts the lives of those affected with this CNS disorder.
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Frick B, Dalnoki-Veress K, Forrest JA, Dutcher J, Murray C, Higgins A. First inelastic neutron scattering studies on thin free standing polymer films. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2003; 12 Suppl 1:S93-S96. [PMID: 15011024 DOI: 10.1140/epjed/e2003-01-022-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2003] [Indexed: 05/24/2023]
Abstract
Glass transition studies in free standing polymer films have revealed values of the transition temperature, T(g), which were substantially reduced below the bulk for sufficiently thin films. Here we report on the preparation of two stacks of free standing polystyrene films: 70 films with a thickness of h approximately 107 nm and 140 films with h approximately 55 nm with equivalent total sample thicknesses of approximately 7.5 microm. We have performed the first measurements on such samples using inelastic neutron scattering, and demonstrate that inelastic neutron scattering experiments, performed on the time-of-flight spectrometer IN6 and the backscattering spectrometer IN16 at the Institut Laue-Langevin, are feasible.
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Murray C, Markos F, Snow HM, Corcoran T, Parfrey N, Shorten GD. Effects of fenoldopam on renal blood flow and its function in a canine model of rhabdomyolysis. Eur J Anaesthesiol 2003; 20:711-8. [PMID: 12974592 DOI: 10.1017/s0265021503001157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVE Our hypothesis was that fenoldopam, a selective DA1 agonist, would protect against rhabdomyolysis-induced renal injury. METHODS We studied the effects of intravenous fenoldopam (0.1-1.0 microg kg(-1) min(-1)) or saline on renal blood flow and function in 10 anaesthetized Labrador dogs in whom rhabdomyolysis and myoglobinuric acute renal failure had been induced by administration of glycerol 50% (10mL kg(-1)) intramuscularly. Haemodynamic measurements including renal blood flow and derived parameters of renal function including creatinine clearance were recorded before and for the 30 min following glycerol injection, and during the 3 h following commencement of each infusion. Serum malondialdehyde concentrations were measured before and 15 min after glycerol intramuscularly, and 30 and 150 min after commencement of the infusion. RESULTS In the fenoldopam group, creatinine clearance was less than placebo at 1 and 2 h after commencing the infusion (12.7 +/- 11.5 versus 31.3 +/- 9.9 mL min(-1), P = 0.04; 8.5 +/- 5.3 versus 20.1 +/- 7.4 mL min(-1), P = 0.03). A 140-fold increase in serum malondialdehyde concentration occurred in one dog (fenoldopam group). CONCLUSION Fenoldopam increased the severity of the renal injury in this canine model of myoglobinuric acute renal failure.
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Malone L, Burgess E, Mercer C, Christeller J, Lester M, Murray C, Phung M, Philip B, Tregidga E, Todd J. Effects of biotinbinding proteins on eight species of pasture invertebrates. ACTA ACUST UNITED AC 2002. [DOI: 10.30843/nzpp.2002.55.3916] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Biotinbinding proteins (BBPs) such as avidin and streptavidin represent potent insect control compounds which could be delivered via transgenic plants The effects of BBPs on some pasture pests were determined Black field cricket nymphs (Teleogryllus commodus) had significantly reduced growth and survival when fed on lettuce leaves painted with purified avidin Adult clover root weevils (Sitona lepidus) were unharmed when fed clover foliage painted with avidin In contrast neonate or oneweekold S lepidus larvae had poor survival when fed on artificial diets containing avidin or streptavidin Neonate larval Argentine stem weevils (Listronotus bonariensis) had significantly reduced survival when fed with artificial diet containing streptavidin or avidin Slugs (Deroceras reticulatum) and snails (Cantareus aspersus) were not harmed when fed with avidinpainted lettuce Similar numbers of eggs were laid and galls produced by the rootknot nematodes Meloidogyne javanica Meloidogyne hapla and Meloidogyne incognita inoculated onto transgenic tobacco plants expressing avidin and nontransgenic controls
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Murray C, Judd D, Snyder P. Evaluation of a post-professional master's program in allied health. JOURNAL OF ALLIED HEALTH 2002; 30:223-8. [PMID: 11828583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Changes in allied health education have precipitated a need to review existing educational programs. As more disciplines require a graduate degree for professional entry, it becomes important to articulate the benefits of advanced, post-professional graduate education for allied health professionals. This article reports results from a study of one interdisciplinary Master of Health Sciences (MHS) program. The intent of the study was to 1) analyze graduates' satisfaction with components of the MHS program; 2) explore the perceived impact of the MHS program on graduates' professional practices; and 3) examine employers' perceptions of the program's effect on graduates' professional behaviors. An investigator-developed written questionnaire was used to gather perspectives from 53 graduates and 27 of their employers. Graduates believed the MHS program had had a positive influence on their employment. Graduates' employers concurred, giving high marks to graduates' skill levels and job performances. Program graduates were active in professional organizations, but few were involved in scholarly activities such as research. Implications for curriculum design of advanced master's programs in allied health are discussed.
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Hynes-Gay P, Chu N, Murray C, Nicholson M. The use of high-frequency oscillatory ventilation in adult ARDS patients. DYNAMICS (PEMBROKE, ONT.) 2002; 12:12-6. [PMID: 11982229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Current ventilatory objectives for adults with ARDS include maximizing gas exchange while minimizing lung injury. To this end, high-frequency oscillatory ventilation (HFOV), a mechanical ventilation strategy that simultaneously avoids end-inspiratory alveolar overdistension and end-expiratory alveolar collapse, has been recommended. HFOV meets these criteria from a theoretical perspective, however, is without the benefit of a prospective randomized clinical trial of CMV versus HFOV to demonstrate that effect. This article provides an overview of high-frequency oscillation, followed by an illustration of how it was applied in the case of a 43-year-old patient who developed respiratory failure 24 hours post-Caesarean section.
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Willis WL, Murray C, Talbott C. Campylobacter isolation trends of cage versus floor broiler chickens: a one-year study. Poult Sci 2002; 81:629-31. [PMID: 12033411 DOI: 10.1093/ps/81.5.629] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
An experiment was carried out over a 1-yr period with broiler chickens to assess the influence of cage and floor rearing environments on the isolation trends of Campylobacter jejuni. The study used 36 7-wk-old broiler chickens that were raised in floor pens and naturally infected with or exposed to C. jejuni during the growout period. These broilers were then leg-banded and split into two groups with 18 per group. The groups were placed in wire cages or in a floor pen with unused litter in separate houses on the same farm. Each broiler was swabbed cloacally monthly to determine the presence of C. jejuni. The yearly average percentage isolation rates were significantly (P < 0.05) higher for the broilers held in the litter floor pen (130/185;66%) when compared to the broilers kept in wire cages (67/193;35%). There was a trend for higher isolation rates in the fall for caged and floor broilers and a decrease in rates near the end of the experimental year (summer) in the caged broilers. Isolation rates for both treatments reached their lowest level for the month of March. No caged broilers tested positive during the last 4 mo of the trial. The long-term cage isolation was linked to a reduced prevalence of C. jejuni. The results from this study suggest that housing environment and time spent in that environment play a major role in the continuing shedding and isolation of C. jejuni in broiler chickens.
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de Boer KA, McArthur S, Murray C, Jansen RPS. O-54. First live birth following blastocyst biopsy and PGD analysis. Reprod Biomed Online 2002. [DOI: 10.1016/s1472-6483(12)60073-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Roberts C, de Boer K, McArthur S, Murray C, Persson J, Wright D. O-41. Three live births following PGD in carriers of Robertsonian and reciprocal translocations. Reprod Biomed Online 2002. [DOI: 10.1016/s1472-6483(12)60060-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Murphy MB, Murray C, Shorten GD. Fenoldopam: a selective peripheral dopamine-receptor agonist for the treatment of severe hypertension. N Engl J Med 2001; 345:1548-57. [PMID: 11794223 DOI: 10.1056/nejmra010253] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Oehlert WH, Natt S, Nguyen L, Murray C, Nsa W, Bratzler DW. Improving influenza and pneumococcal immunizations in Oklahoma: preliminary results of a survey of Medicare beneficiaries. THE JOURNAL OF THE OKLAHOMA STATE MEDICAL ASSOCIATION 2001; 94:461-8. [PMID: 11642002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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Goddard PJ, Summers RW, Macdonald AJ, Murray C, Fawcett AR. Behavioural responses of red deer to fences of five different designs. Appl Anim Behav Sci 2001; 73:289-298. [PMID: 11434963 DOI: 10.1016/s0168-1591(01)00150-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Capercaillie, a large species of grouse, are sometimes killed when they fly into high-tensile deer fences. A fence design which is lower or has a less rigid top section than conventional designs would reduce bird deaths, but such fences would still have to be deer-proof. The short-term behavioural responses of farmed red deer (Cervus elaphus) to fences of five designs, including four that were designed to be less damaging to capercaillie, were measured. Five deer were located on one side of a fence with a larger group (20 animals), from which they had been recently separated, on the other. The efficacy of fences in preventing deer from the small group from rejoining the larger group was also recorded. In addition to a conventional deer fence (C) the four new designs were, an inverted "L" shape (L), a fence with offset electric wire (E), a double fence (D) and a fence with four webbing tapes above (W). Four replicate groups of deer were each tested for 3 days with each fence design. Deer paced the test fence line relatively frequently (a proportion of 0.09 scan observations overall) but significantly less when deer were separated by fences E or C compared to L, W or D (overall difference between fence types, P<0.001). Deer separated by fence E spent significantly more time pacing perimeter fences than deer separated by fences of other types (overall difference between fence types, P<0.01) but deer separated by fence C maintained a low level of fence pacing overall. Analysis of behaviour patterns across the first day and the 3 days of exposure suggested that the novelty of the test fences, rather than the designs per se, influenced the behaviour of the deer. Over the course of the study, no deer crossed either C or L. Three deer crossed E and two deer crossed both W and D. On this basis, field testing, particularly of fence L, would be a useful next step.
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Murray C, Shipman P, Khangure M, Chakera T, Robbins P, McAuliffe W, Davis S. Lhermitte-Duclos disease associated with Cowden's syndrome: case report and literature review. AUSTRALASIAN RADIOLOGY 2001; 45:343-6. [PMID: 11531761 DOI: 10.1046/j.1440-1673.2001.00933.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Lhermitte-Duclos disease (LDD) is a rare entity that may occur in the setting of Cowden's syndrome (CS). Accurate preoperative diagnosis can be made on the characteristic CT and MR appearances, thereby obviating the need for biopsy. It is important to be aware of the link between LDD and CS so that appropriate genetic counselling and tumour surveillance can be undertaken.
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Abstract
During a 20 yr period (1978 to 1998), 233 isolates of Salmonella spp. were cultured from 179 wildlife animals (representing 25 species), 32 crocodile (Crocodylus porosus) eggs and six crocodile nesting sites, and represented 59 different serotypes. Salmonella serotype Virchow, the major serotype infecting humans in north Queensland, (Australia) was common in macropodids, but was not found in reptiles and was isolated only once from cane toads (Bufo marinus). Investigations of human cases of salmonellosis should include simultaneous studies on wild and domestic animals in contact with the case.
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Dalnoki-Veress K, Forrest JA, Murray C, Gigault C, Dutcher JR. Molecular weight dependence of reductions in the glass transition temperature of thin, freely standing polymer films. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 63:031801. [PMID: 11308668 DOI: 10.1103/physreve.63.031801] [Citation(s) in RCA: 242] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2000] [Revised: 07/10/2000] [Indexed: 05/23/2023]
Abstract
We have used transmission ellipsometry to perform a comprehensive study of the glass transition temperature T(g) of freely standing polystyrene films. Six molecular weights M(w), ranging from 575 x 10(3) to 9100 x 10(3), were used in the study. For each M(w) value, large reductions in T(g) (as much as 80 degrees C below the bulk value) were observed as the film thickness h was decreased. We have studied in detail the dependence of the T(g) reductions on M(w) in a regime dominated by chain confinement effects. The empirical analysis presented is highly suggestive of the existence of a mechanism of mobility in thin freely standing films that is inhibited in the bulk and distinct from the usual cooperative motion associated with the glass transition.
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