| 1. |
- Ericson, Mats L., et al.
(författare)
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Processing and mechanical properties of orientated preformed glass-mat-reinforced thermoplastics
- 1993
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Ingår i: Composites Science And Technology. - 0266-3538 .- 1879-1050. ; 49:2, s. 121-130
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Tidskriftsartikel (refereegranskat)abstract
- The stiffness and strength of moulded, glass-mat-reinforced thermoplastics (GMT) components would be increased by the presence of highly orientated fibres at critical locations. A previously described method to produce preformed GMT materials was therefore further developed to make orientation of the fibres in the preform possible. Two ‘orientation plates' were used to orientate the fibres during spray-up of a glass-fibre/polyethylene preform. The preform was then heated by hot gas and compression moulded. The ratio of the highest and lowest stiffnesses of a given plate was in the range of 27 to 38. Micromechanics equations were used with classical lamination theory to design a model laminate with stiffness properties in close agreement with experimental data. Reasons for the relatively wide fibre orientation distribution and low fibre length efficiency factor obtained for the model laminate are discussed and improvements suggested.
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| 2. |
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| 3. |
- Holte, J, et al.
(författare)
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Enhanced early insulin response to glucose in relation to insulin resistance in women with polycystic ovary syndrome and normal glucose tolerance.
- 1994
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 78:5, s. 1052-8
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Tidskriftsartikel (refereegranskat)abstract
- Insulin secretion in response to iv glucose and insulin sensitivity (euglycemic hyperinsulinemic clamp) were evaluated in 49 women with polycystic ovary syndrome (PCOS) [body mass index (BMI), 17.6-37.2 kg/m2] and 42 control subjects (BMI, 18.8-38.1 kg/m2). Seven women with PCOS exhibited glucose intolerance with subnormal insulin secretion. Compared with control subjects, women with PCOS and normal glucose tolerance had an increased (36-56%) insulin increment, not explained by insulin resistance, and over the whole range of BMI. In contrast, insulin sensitivity was similar in women with PCOS and control subjects at BMI 21 kg/m2, but showed a more pronounced decline with increasing BMI in women with PCOS, who had 35% and 70% lower insulin sensitivities at BMI 28 and 35 kg/m2, respectively. After adjusting for truncal-abdominal sc fat distribution, which was more pronounced in the women with PCOS, the two groups had similar insulin sensitivity over the entire range of BMI (P = 0.9), whereas the difference in insulin increment was insignificant after adjusting for the free androgen index (testosterone x 100/sex hormone binding globulin; P = 0.16). Hemoglobin A1C levels were lower in women with PCOS than in the control subjects. It is concluded that the early insulin response to glucose was increased in women with PCOS, not accounted for by insulin resistance, closely associated to the increased androgenicity, and present also at low-normal BMI. In contrast, insulin resistance was seen only at higher BMI levels and was largely determined by the increased truncal-abdominal fat mass in PCOS.
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| 4. |
- Ojehagen, Agneta, et al.
(författare)
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A 6‐Year Follow‐Up of Alcoholics After Long‐Term Outpatient Treatment
- 1994
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Ingår i: Alcoholism: Clinical and Experimental Research. - : Wiley. - 0145-6008 .- 1530-0277. ; 18:3, s. 720-725
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Tidskriftsartikel (refereegranskat)abstract
- The predictors of the long‐term outcome in alcoholics (n= 50) who had been treated in a 2‐year outpatient treatment program were investigated. Previously, the sample had been followed up personally 2 years after the termination of treatment. This study is a repeated, independent follow‐up of the same sample over a 4‐year period, 3–6 years after termination of treatment. Outcome could be categorized in 38 subjects. Patients with a favorable outcome during at least 2 years of the 4‐year follow‐up period (n= 21), who were categorized as a positive outcome group, were compared with the other patients (n= 17). There was no significant correlation between initial patient characteristics and outcome 3–6 years after treatment. Drinking outcome during the 1st half‐year of treatment had no correlation to positive drinking outcome in years 3–6, whereas there was a positive correlation for later phases of treatment and outcome reaching a significant level during the 2nd and 4th half‐year of treatment. A favorable drinking outcome during years 1–2 after treatment had a positive significant correlation to outcome in years 3–6 after treatment [i.e., 80% of the patients with a favorable outcome during the 1st follow‐up period also had a positive outcome during the 2nd follow‐up period, and 72% of those who had an unfavorable outcome during the 1st follow‐up period had an unfavorable outcome also during the 2nd follow‐up period (x2 test = 10.4, p < 0.001). Psycho‐social adjustment at the 6‐year follow‐up did not differ significantly between subjects in the positive outcome group and subjects in the negative outcome group.
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| 5. |
- Pessah-Rasmussen, H, et al.
(författare)
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Human fibroblasts lacking trans-stilbene oxide active glutathione transferase exhibit increased cell death when exposed to polycyclic aromatic hydrocarbons
- 1992
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Ingår i: Pharmacology and Toxicology. - : Wiley. - 0901-9928 .- 1600-0773. ; 70:5 Pt 1, s. 5-361
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Tidskriftsartikel (refereegranskat)abstract
- Glutathione transferases (GST) are detoxifying enzymes who act with many endogenous and exogenous substances such as polycyclic aromatic hydrocarbons (PAH). The GST activity towards trans-stilbene oxide (GST-tSBO) is inherited in an autosomal dominant fashion and can be separated in high (GST-positive) and low (GST-negative) phenotypes when measured in blood. Human fibroblast cultures were established from males matched for age, smoking habits and clinical manifestations of atherosclerosis. Matched pairs of GST-negative and GST-positive fibroblasts were studied. There was a very strong correlation between the levels of GST-tSBO in peripheral blood and in cultured fibroblasts within the same individual. When fibroblasts were exposed to benzo(a)pyrene (BP) or dimethylbenzanthracene (DMBA) GST-negative cells produced relatively more collagen than GST-positive cells. GST-negative fibroblasts showed a greater cell death than GST-positive fibroblasts as well among controls as after exposure to PAH. It is concluded that lack of GST-tSBO is easily discriminated in cultured skin fibroblasts. GST-negative and GST-positive fibroblasts showed different susceptibility towards some toxic stimuli that might be of importance in atherogenesis.
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| 6. |
- Pessah-Rasmussen, H, et al.
(författare)
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Increased smooth muscle cell proliferation by dimethylbenzanthracene is correlated to variations in activity of ornithine decarboxylase but not arylhydrocarbonhydroxylase
- 1991
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Ingår i: Artery. - 0098-6127. ; 18:5, s. 55-240
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Tidskriftsartikel (refereegranskat)abstract
- Polycyclic aromatic hydrocarbons of cigarette smoke have been suggested to be involved in atherogenesis. After being converted to epoxides by monooxidases in the arterial wall the hydrocarbons may exert toxic or mutagenic effects on the smooth muscle cells (SMC). In a previous study we found that dimethylbenzanthracene (DMBA), an inducer of arylhydrocarbonhydroxylase (AHH), increased SMC proliferation and viability. In the present work we intended to study whether these effects were mediated by AHH. Alpha-naphtoflavone (ANF), a non specific AHH inhibitor, decreased SMC proliferation. The effects of ANF were totally counteracted by serum, partially by albumin and not at all by platelet derived growth factor. AHH activity was not detectable nor basally nor after induction in SMC, and this made us conclude that the effects of DMBA and ANF on SMC proliferation were not mediated by AHH. On the other hand the activity of ornithine decarboxylase was influenced by DMBA and ANF in parallel to proliferation, suggesting the involvement of this enzyme in the described DMBA effects on SMC proliferation. This mechanism might be of relevance for the pathogenesis of atherosclerosis especially in relation to cigarette smoking.
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| 7. |
- Stark, A.K., et al.
(författare)
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Effect of atomic oxygen on the mechanical properties of highly graphitized carbon fibers
- 1994
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223 .- 1873-3891. ; 32:4, s. 641-644
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Tidskriftsartikel (refereegranskat)abstract
- Material degradation is a serious problem for large structural members that operate in low earth orbit for a long time. In order to study how the mechanical properties of the fibers change in this environment, highly graphitized polyacrylonitrile-based high modulus carbon fibers have been exposed to different fluences of atomic oxygen, the dominant atmospheric element in low earth orbit. Tensile tests were performed on these fibers. Young's modulus and tensile strength decreased with increasing exposure to atomic oxygen. Scanning electron microscopy revealed that the surface of the carbon fiber was severely degraded by the atomic oxygen, and this explains the decreases in Young's modulus and tensile strength
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| 8. |
- Udén, P, et al.
(författare)
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Preoperative localization in unilateral parathyroid surgery. A cost-benefit study on ultrasound, computed tomography and scintigraphy
- 1990
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Ingår i: Acta Chirurgica Scandinavica. - 0001-5482. ; 156:1, s. 29-35
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Tidskriftsartikel (refereegranskat)abstract
- In 50 patients with primary hyperparathyroidism, investigation before initial neck exploration included ultrasonography, computed tomography and 99technetium-201thallium subtraction scintigraphy. The sensitivity for correct preoperative localization was 50%, 54% and 56%, respectively. There was marked inter-observer variation in assessment of ultrasonography and computed tomography, while scintigrams were evaluated by only one person. The scintigraphic sensitivity increased with size of the glands. In cases where correct preoperative localization permitted unilateral parathyroidectomy, the time for surgery and anesthesia was significantly reduced. A cost-benefit analysis, however, revealed that the financial saving from this time reduction was outweighed by the cost of the localization procedures. The authors conclude that investigations for definition of enlarged parathyroid glands are not indicated prior to unilateral parathyroidectomy.
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| 9. |
- Varna, Janis, et al.
(författare)
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Specimen size effects on modulus of GMT and other inhomogeneous composites
- 1992
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Ingår i: Journal of Thermoplastic Composite Materials. - : SAGE Publications. - 0892-7057 .- 1530-7980. ; 5:2, s. 105-114
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Tidskriftsartikel (refereegranskat)abstract
- Mean values and standard deviations are often used to characterize certain mechanical properties. It is widely known that some properties, e.g., tensile strength of brittle solids and their standard deviations, are affected by the volume studied. In the pres ent study, the mean value and the standard deviation for the longitudinal elastic modulus of a cuboid specimen are treated. A model to predict the mean values and standard devia tions for varying lengths and widths is presented. Experimental data from the literature for glass mat reinforced polypropylene is used to show that the model shows excellent ac curacy with experimental data
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| 10. |
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