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| 9. |
- Graves, J R, et al.
(författare)
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Survivors of out of hospital cardiac arrest: their prognosis, longevity and functional status.
- 1997
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Ingår i: Resuscitation. - : Elsevier Ireland Ltd. - 0300-9572 .- 1873-1570. ; 35:2, s. 117-21
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports, consistent with Utstein Style definitions, 13 years experience observing out-of-hospital cardiac arrest survivors' prognosis, longevity and functional status. We report for all patients, available outcome information for out-of-hospital cardiac arrest survivors in Göteborg Sweden between 1980 and 1993. Patients were followed for at least 1 year and some for over 14 years. From 1980 to 1993 Göteborg EMS treated 3754 out-of-hospital cardiac arrests. 9% (n = 324) were discharged from the hospital alive. Survivors' median age was 67 and 21% (n = 67) were women. Mortality rate was: 21% (n = 61) at 1 year; 56% (n = 78) by 5 years; and 82% (n = 32) by 10 years following the arrest. During the first 3 years, 16% (n = 46) experienced another cardiac arrest, 19% (n = 53) had an acute myocardial infraction and a total of 81% (n = 232) were rehospitalized for various conditions. 14% (n = 40) returned to previous employment, and 74% (n = 229) had retired before their arrest occurred. Cerebral performance categories (CPC) scores were: At hospital discharge N = 324; Data available for 320-1 = 53% (n = 171), 2 = 21% (n = 66), 3 = 24% (n = 77), 4 = 2% (n = 6). One year post arrest N = 263; Data available for 212-1 = 73% (n = 156), 2 = 9% (n = 18), 3 = 17% (n = 36), 4 = 1% (n = 2). Overall, 21% (n = 61) of cardiac arrest survivors died during the first year, and an additional 16% (n = 46) experienced another arrest. 73% of those patients who were still alive after 1 year returned to pre-arrest function.
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| 10. |
- Axelsson, Åsa B., 1955, et al.
(författare)
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Factors surrounding cardiopulmonary resuscitation influencing bystanders' psychological reactions.
- 1998
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Ingår i: Resuscitation. - : Elsevier Ireland Ltd. - 0300-9572 .- 1873-1570. ; 37:1, s. 13-20
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Tidskriftsartikel (refereegranskat)abstract
- The incidence of Sweden's out-of-hospital cardiac arrests averages 10000 annually. Each year bystanders initiate cardiopulmonary resuscitation (CPR) approximately 2000 times prior to arrival of emergency medical service (EMS). The aim of this study was to identify factors influencing the bystanders psychological reactions to performing CPR. We mailed a questionnaire to all bystanders who reported performing CPR to the CPR Centre of Sweden from autumn 1992 to 1995. The study included 544 bystander reports. Nine factors were found to be associated with bystanders experience in a univariate analysis. Among these were victim outcome (p < 0.0001), CPR duration (p = 0.0009) and their experience of the attitude of the EMS personnel (p = 0.004). In a multivariate logistic regression model, lack of debriefing following the intervention (p = 0.0001) and fatal victim outcome (p = 0.03) were independent predictors of a negative bystander psychological reaction. The importance of having someone to talk to following an intervention and the EMS personnel concern for the rescuer should be emphasised. The goal should be that critical incident debriefing is available to every bystander following his or her CPR attempt.
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| 11. |
- Derefeldt, G., et al.
(författare)
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Improvement of tactical situation awareness with colour-coded horizontal-situation displays in combat aircraft
- 1999
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Ingår i: Displays (Guildford). - 0141-9382 .- 1872-7387. ; 20:4, s. 171-184
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Tidskriftsartikel (refereegranskat)abstract
- In the multi-role combat aircraft Gripen, the monochrome head-down displays in the cockpit are to be upgraded in colour. In the present study, the effects of colour-coded displays on visual search and situation awareness (SA) were studied in a real-time simulation of an air-to-air mission with test pilots as subjects. Gripen's monochrome colour scheme was compared to two chromatic (dichrome, polychrome) colour schemes. A 3×2×2 factorial within subjects design was used; the three colour schemes each with two different background conditions (simple and complex) and two different symbol configurations. The pilot had two tasks during the simulation: (1) to track a manoeuvring aircraft within specified limits by using the head-up display (HUD), and (2) to detect the appearance of a priority target on the head-down horizontal-situation display (HSD). Deviations in flight path angle and reaction times for target detection were recorded. After the test runs, the pilot answered questions and ranked the colour schemes in different respects. The pilot also rated them for SA using a subjective rating technique on cognitive compatibility (CC-SART). The results show that colour is advantageous in comparison to the monochrome display: The ranks on situation awareness and preference ratings were higher for the chromatic schemes, and with the complex background, the reaction times were significantly lower for the polychrome colour code. In summary, the results indicate that colour can improve tactical SA in combat aircraft.
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| 12. |
- Finizia, Caterina, 1961, et al.
(författare)
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Advanced laryngeal cancer T3-T4 in Sweden: a retrospective study 1986-1990. Survival and locoregional control related to treatment.
- 1996
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Ingår i: Acta oto-laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 116:6, s. 906-12
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Tidskriftsartikel (refereegranskat)abstract
- Different treatment modalities for advanced laryngeal cancer are much discussed in the literature. One-hundred-and-sixty patients with T3-4, N0-3, M0-1 laryngeal cancer diagnosed in Sweden between 1986 and 1990 were retrospectively analysed. One hundred (65 T3: 35 T4) received radical radiotherapy with salvage surgery (RRSS) in case of residual or recurrent disease. Thirty-eight (11T3: 27 T4) patients received surgery with or without radiotherapy (S +/- RT). Twenty-two patients received no treatment. After a median follow up of 4.4 years, the estimated 5-year actuarial corrected survival and 3-year locoregional control were 59% and 44% for T3 RRSS and 47% and 54% for T3 S +/- RT. No significant difference between the different treatment modalities was found. The 5-year corrected survival rate and the locoregional control at 3 years between T4-RRSS (32%; 26%) and T4-S + RT (58%; 68%) groups were significantly different (p < 0.05 and p < 0.01). This might suggest that surgery with or without radiotherapy still has its place as a treatment modality for patients with advanced T4 laryngeal carcinoma.
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- Herlitz, Johan, et al.
(författare)
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Rhythm changes during resuscitation from ventricular fibrillation in relation to delay until defibrillation, number of shocks delivered and survival
- 1997
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Ingår i: Resuscitation. - : Elsevier Ireland Ltd. - 0300-9572 .- 1873-1570. ; 34:1, s. 17-22
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To describe rhythm changes during the initial phase of resuscitation from ventricular fibrillation in relation to the interval between collapse and defibrillation, to survival and to bystander-initiated cardiopulmonary resuscitation (CPR). PATIENTS: All patients who suffered out-of-hospital cardiac arrest between 1980 and 1992, who were reached by the emergency medical service system (EMS), in whom resuscitation attempts were initiated and who were found in ventricular fibrillation. RESULTS: In all, 1216 patients were included in the study. Among patients who converted to a pulse-generating rhythm after the first defibrillation (n = 119) were 56% discharged from hospital as compared with 6% among patients who converted to asystole. The corresponding figures after the third defibrillation were 49% and 2%, respectively, and after the fifth defibrillation 28% and 7%, respectively. Among patients in whom the first defibrillation took place less than 5 min after collapse, 28% directly converted to a pulse-generating rhythm as compared with 3% when the first defibrillation took place 12 min or more after collapse. CONCLUSION: Among patients who suffer out-of-hospital cardiac arrest and are found in ventricular fibrillation, there is a strong relationship between survival and initial rhythm changes after defibrillation. These rhythm changes are directly related to the interval between collapse and the first defibrillation.
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| 18. |
- Holmberg, M, et al.
(författare)
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Surface force studies of Langmuir-Blodgett cellulose films
- 1997
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Ingår i: Journal of Colloid and Interface Science. - 0021-9797 .- 1095-7103. ; 186, s. 369-381
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Tidskriftsartikel (refereegranskat)abstract
- The interactions between cellulose surfaces, between chitosan coated surfaces and between one cellulose surface and one chitosan coated surface have been studied using the interferometric surface forces apparatus (SFA). The cellulose surfaces were prepared by depositing trimethylsilyl cellulose on hydrophobized mica using the Langmuir-Blodgett technique. The surfaces were desilylated in humid HCl atmosphere to obtain regenerated cellulose. ESCA measurements and wetting studies demonstrated that the desilylation process was effective. AFM studies showed the cellulose surfaces to be smooth with a root mean square roughness of 0.16 nm. Surface force and ellipsometry measurements illustrate that the cellulose film swells considerably in humid air and in water, suggesting that it is mostly amorphous. The interaction between two cellulose surfaces is dominated by a steric repulsion caused by a few dangling tails. On separation an attractive force was present both between two cellulose surfaces and between one cellulose surface and one chitosan surface. The long-range interaction between cellulose and chitosan was shown to be attractive.
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| 23. |
- Andréassob, A-Ch, et al.
(författare)
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Characteristics and outcome among patients with a suspected in hospital cardiac arrest
- 1998
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Ingår i: Resuscitation. - : Elsevier Ireland Ltd. - 0300-9572 .- 1873-1570. ; 39:1-2, s. 23-31
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To describe the characteristics and outcome among patients with a suspected in-hospital cardiac arrest. METHODS: All the patients who suffered from a suspected in-hospital cardiac arrest during a 14-months period, where the cardiopulmonary resuscitation (CPR) team was called, were recorded and described prospectively in terms of characteristics and outcome. RESULTS: There were 278 calls for the CPR team. Of these, 216 suffered a true cardiac arrest, 16 a respiratory arrest and 46 neither. The percentage of patients who were discharged alive from hospital was 42% for cardiac arrest patients, 62% for respiratory arrest and 87% for the remaining patients. Among patients with a cardiac arrest, those found in ventricular fibrillation/ventricular tachycardia had a survival rate of 64%, those found in asystole 24% and those found in pulseless electrical activity 10%. Among patients who were being monitored at the time of arrest, the survival rate was 52%, as compared with 27% for non-monitored patients (P= 0.001). Among survivors of cardiac arrest, a cerebral performance category (CPC) of 1 (no major deficit) was observed in 81% at discharge and in 82% on admission to hospital prior to the arrest. CONCLUSION: We conclude that, during a 14-month period at Sahlgrenska University Hospital in Göteborg, almost half the patients with a cardiac arrest in which the CPR team was called were discharged from hospital. Among survivors, 81% had a CPC score of 1 at hospital discharge. Survival seems to be closely related to the relative effectiveness of the resuscitation organisation in different parts of the hospital.
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| 25. |
- Berg, Cecilia, 1969-, et al.
(författare)
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Direct solid-phase sequence analysis of the human p53 gene by use of multiplex polymerase chain reaction and alpha-thiotriphosphate nucleotides.
- 1995
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 41:10, s. 1461-6
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Tidskriftsartikel (refereegranskat)abstract
- Among the candidate cancer-prognostic genes is the p53 tumor suppressor gene, which, when mutated, plays an important role in the development of many types of cancers. To facilitate robust large-scale DNA analysis of microdissected tumor biopsies, we describe a multiplex/nested PCR approach for a simultaneous outer amplification of exons 4-9 of the human p53 gene with parallel amplification of the HLA-DQB1 locus, involving a total of 14 primers. This approach reduces the required number of cells for analysis and avoids any variation in the amplifications of the individual p53 exons during the common outer amplification step. The HLA sequencing allows sample identification because the DQB1 locus is highly polymorphic and is thereby patient-specific. The p53 and HLA amplicons are analyzed by solid-phase sequencing in a semiautomated format. To improve the DNA sequence quality, we used 2'-deoxyribonucleoside 5'-O-1-thiotriphosphates in the sequencing reactions.
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| 30. |
- Elftonson, JE, et al.
(författare)
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Adhesion of Streptococcus sanguis to porous and non-porous substrates with well-defined surface energies
- 1996
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Ingår i: Journal of Adhesion Science and Technology. - 0169-4243 .- 1568-5616. ; 10, s. 761-770
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Tidskriftsartikel (refereegranskat)abstract
- Adhesion of the oral bacterium Streptococcus sanguis was investigated on two series of surfaces, one solid, non-porous and one porous with a pore diameter centered around 0.2 µm. Each series consisted of four substrates with varying surface free energies: pure aluminum oxide, PEG modified aluminum oxide, and two types of silanized aluminum oxide. The surface composition was analyzed by ESCA and the surface free energy and acid-base character were determined by contact angle measurement using water, formamide and diiodomethane according to Van Oss and Good. Contact angle measurements were conducted on non-porous substrates which had been subjected to the same silanization procedure as the porous ones. Untreated aluminum oxide and PEG modified aluminum oxide were both hydrophilic and gave water contact angles of less than 10°. One silanization procedure gave a surface of intermediate hydrophobicity, with a y-tot of 47.5 mN/m; the other gave a strongly hydrophobic surface of y-tot = 27.4 mN/m. Adhesion of S. sanguis was measured by using radiolabelled bacteria. It was demonstrated that more bacteria adhered to the porous than to the non_x001F_porous substrate and that the PEG treatment, as well as the two sil aniz ation pro cedures, resulted in a decreas e in bacterial adhesion, b oth to the controls treated with aqueous buffer and to surfaces treated with fresh saliva.
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- Gutfelt, S, et al.
(författare)
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Microemulsions as reaction medium for surfactant synthesis
- 1997
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Ingår i: Colloids and Surfaces A. - 0927-7757 .- 1873-4359. ; 128, s. 265-271
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Tidskriftsartikel (refereegranskat)abstract
- Various microemulsion formulations were evaluated as reaction medium for synthesis of a surface active compound, decyl sulfonate, from decyl bromide and sodium sulfite. The reaction rate was fast both in water-in-oil and in bicontinuous microemulsions based on nonionic surfactant. Two-phase systems with added phase transfer agent (quaternary ammonium salt or crown ether) was much less efficient. It is postulated that the low efficiency of the phase transfer agents in catalyzing the reaction is caused by strong ion pair formation between the product formed, decyl sulfonate, and the phase transfer agent. To prove this point decyl bromide was reacted with two other nucleophiles, sodium cyanide and sodium azide. Neither of these give a reaction product that can form ion pair with the phase transfer agent. With these reagents phase transfer catalysis was almost as efficient as synthesis in microemulsion. It was also demonstrated that the rate of decyl sulfonate formation in microemulsion can be increased further by addition of a small amount of cationic surfactant. The choice of surfactant counterion is decisive of the effect on reaction rate, however. Whereas a small non-polarizable ion, such as acetate, gives a considerable reaction rate increase, a large polarizable ion, such as bromide, slows down the reaction. Bromide is believed to interact so strongly with the interface that it prevents the reacting ion, sodium sulfite to reach into the interfacial zone.
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| 36. |
- Herlitz, Johan, 1949, et al.
(författare)
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Lidocaine in out-of-hospital ventricular fibrillation. Does it improve survival?
- 1997
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Ingår i: Resuscitation. - 0300-9572. ; 33:3, s. 199-205
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Tidskriftsartikel (refereegranskat)abstract
- A large proportion of cardiac arrests outside hospital are caused by ventricular fibrillation. Although it is frequently used, the exact role for treatment with lidocaine in these patients remains to be determined.
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| 37. |
- Herlitz, Johan, et al.
(författare)
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Lidocaine in out-of-hospital ventricular fibrillation. Does it improve the survival?
- 1997
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Ingår i: Resuscitation. - : Elsevier Ireland Ltd. - 0300-9572 .- 1873-1570. ; 33:3, s. 199-205
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: A large proportion of cardiac arrests outside hospital are caused by ventricular fibrillation. Although it is frequently used, the exact role for treatment with lidocaine in these patients remains to be determined. AIM: To describe the proportion of patients with witnessed out-of-hospital cardiac arrest found in ventricular fibrillation who survived and were discharged from hospital in relation to whether they were treated with lidocaine prior to hospital admission. Patients and treatment: All the patients with out-of-hospital cardiac arrest found in ventricular fibrillation in Göteborg between 1980 and 1992 in whom cardiopulmonary resuscitation (CPR) was initiated by our emergency medical service (EMS). During the observation period, some of the EMS staff were authorized to give medication and some were not. RESULTS: In all, 1,360 patients were found in ventricular fibrillation, with detailed information being available in 1,212 cases (89%). Lidocaine was given in 405 of these cases (33%). Among patients with sustained ventricular fibrillation, those who received lidocaine had a return of spontaneous circulation (ROSC) more frequently (P < 0.001) and were hospitalized alive more frequently (38% vs. 18%, P < 0.01). However, the rate of discharge from hospital did not significantly differ between the two groups. Among patients who were converted to a pulse-generating rhythm, those who received lidocaine on that indication were more frequently alive than those who did not receive such treatment (94% vs. 84%; P < 0.05). However, the rate of discharge did not significantly differ between the two groups. CONCLUSION: In a retrospective analysis comparing patients who received lidocaine with those who did not in sustained ventricular fibrillation and after conversion to a pulse-generating rhythm, such treatment was associated with a higher rate at ROSC and hospitalization but was not associated with an increased rate of discharge from hospital.
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| 41. |
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| 42. |
- Holmberg, AR, et al.
(författare)
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Ion exchange tumor targeting: a new approach
- 1999
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Ingår i: Clinical cancer research : an official journal of the American Association for Cancer Research. - 1078-0432. ; 5:1010 Suppl, s. 3056S-3058S
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Tidskriftsartikel (refereegranskat)
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| 45. |
- Holmberg, J.A., et al.
(författare)
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Manufacturing and performance of RTM U-beams
- 1997
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Ingår i: Composites. Part A, Applied science and manufacturing. - 1359-835X .- 1878-5840. ; 28:6, s. 513-521
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Tidskriftsartikel (refereegranskat)abstract
- Geometrical limitations and robustness of resin transfer moulding were investigated for single curved laminates. The design of experiments approach was used to determine how the out of plane tensile strength is affected by variations in performing method, radius, fibre content and vacuum assistance. U-beams with an inner radius of 0.8 mm were manufactured and demonstrated good mechanical performance. The strength of these beams was in fact less sensitive to defects than the strength of beams with a 5 mm radius. Different preforming methods can have a strong influence on beam strength due to effects on the void content in the finished laminates. The particular preforming problems encountered are described and possible solutions are suggested and tested. For example utilisation of vacuum assistance during mould filling reduces void content, which in turn tends to reduce the sensitivity of the beam strength to other defects such as wrinkling.
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| 46. |
- Holmberg, J.A., et al.
(författare)
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Micromechanisms of delamination failure in RTM U-beams
- 1997
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Ingår i: Composites. Part A, Applied science and manufacturing. - 1359-835X .- 1878-5840. ; 28:8, s. 709-717
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study, resin transfer moulded U-beams were subjected to opening tensile loads applied to the flanges. The failure behaviour was sensitive to the void content of the material. In the present study, we use optical microscopy of polished edges to observe mechanisms of failure in-situ as delaminations develop in the beam radius. Descriptions of these failure mechanisms are presented. Voids were found to facilitate the growth phase of the delamination process in the beam radius. The mechanisms described will be used in a forthcoming stress analysis to explain the experimentally observed failure behaviour of beams with different radii and void contents.
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| 47. |
- Holmberg, J. Anders
(författare)
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Resin transfer moulded composite materials : processing, structure, property relationships
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis contains analysis of the performance of polymer composites manufactured by resin transfer moulding (RTM). The thesis consists of six papers, where the first two deals with the tensile strength of composites reinforced with randomly oriented glass fibres, which still is the most common reinforcement in RTM manufacturing. The following four papers covers aspects of manufacturing induced defects, out-of-plane strength and dimensional tolerances of carbon fibre reinforced high temperature epoxy, which is a relatively new application for RTM. The apparent tensile strength of random fibre composites is usually significantly higher if measured in bending than in tension. In Paper A, it is shown that the deduction of strength from flexural tests is complicated by several factors, leading to large errors if not accounted for. Approximate closed form expressions are derived to account for friction at the support rollers, nonlinear material behaviour and large deflections and suggested for future use. It is then shown that properly deduced flexural strengths can be predicted from tensile test data by Weibull theory, if applied on effective fibre stress. In Paper B, the Weibull theory is extended to biaxial load cases for random fibre composites. Failure strain predictions based on tensile test data are in good agreement with experimental results from three- and four-point bending and biaxial bending. In Paper C, the robustness and geometrical limitations of resin transfer moulding were investigated for single curved laminates. The design of experiments approach was used to determine how the out of plane tensile strength is affected by variations in preforming method, radius, fibre content and vacuum assistance. Carbon fibre /epoxy U-beams with an inner radius of 0.8 mm were manufactured and demonstrated good mechanical performance. The strength of these beams were in fact less sensitive to defects than the strength of beams with a 5 mm radius. Beams with a 5 mm radius were very sensitive to the presence of voids. A good correlation was obtained between local void content and beam strength, indicating that void content is the only important defect. In-situ optical microscopy was used in Paper D to observe the micromechanisms of failure as delaminations develop in the beam radius. Beams with and without voids were studied to determine how the voids affect the failure initiation. The failure mechanism proposed, based on the observations, involves the position of the voids and the microstructure of the reinforcement. The material system investigated was a plain carbon fibre weave impregnated with epoxy by resin transfer moulding. The voids were primarily located in the matrix rich regions created by the crimp in the reinforcement. Voids were found to have no effect on the initial formation of a debond crack at the interface between adjacent fibre bundles. Instead, the voids increase the stress concentration at the crack tip and therefore crack growth starts at a lower load. In Paper E this issue is brought further by numerical modelling of an initial crack adjacent to a void. The calculated increase in energy release rate, due to the presence of a void, suggests a strength reduction in qualitative agreement with the experimental results presented in Paper C. The reasons for why the smaller radius exhibits a lower defect sensitivity is also discussed in Paper E. Finally, Paper F is a study of the springback phenomenon. The mechanisms responsible for springback during a typical RTM cure schedule are discussed. An approximate model for prediction of springback is developed, incorporating the effects of chemical shrinkage and the phase change at the glass transition temperature. The effect from chemical shrinkage is estimated from fibre and matrix properties and it is demonstrated both theoretically and experimentally that the effect from chemical shrinkage is significant. Model predictions of springback angles are in good agreement with experimental data from the beam series presented in Paper C.
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| 48. |
- Holmberg, K, et al.
(författare)
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Microemulsions as reaction medium for a substitution reaction
- 1996
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Ingår i: Progress in Colloid and Polymer Science. - 0340-255X .- 1437-8027. ; 100, s. 281-285
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Tidskriftsartikel (refereegranskat)abstract
- Synthesis of sodium decyl sulfonate from 1-bromodecane and sodium sulfite was performed in microemulsions based on nonionic surfactant, in liquid crystals and in 2-phase systems with or without a phase transfer agent added. The reactions were fast in both bicontinuous and W/O microemulsion, slower in liquid crystal and very sluggish in 2-phase systems also in the presence of a Q salt or a crown ether. Addition of a small amount of anionic surfactant to the microemulsion systems decreased reaction rate. Addition of cationic surfactant either increased or decreased the reaction rate depending on the choice of counterion.
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| 49. |
- Holmberg, Krister, et al.
(författare)
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Poly(ethylene glycol) grafting as a way to prevent protein adsorption and bacterial adherence
- 1998
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Ingår i: Mittal Festschrift on Adhesion Science and Technology. - : VSP International Science Publishers. ; , s. 443-460
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Bokkapitel (refereegranskat)abstract
- Grafting of poly(ethylene glycol) (PEG) is an effective way of preventing adsorption of proteins and bacteria to hydrophobic surfaces. The paper discusses and compares two different routes of attaching PEG chains to surfaces: adsorption of block copolymers of ethylene oxide and propylene oxide (EO-PO block copolymers) and grafting via use of an anchoring polymer, poly(ethylene imine) (PEI). An overriding goal is to achieve a dense packing of PEG chains. The best effect in terms of protein and bacteria rejection is obtained by adsorbing a preformed copolymer of PEG grafted to PEI on a negatively charged surface. Using PEGs of molecular weight 1,500 g/mol or higher, protein adsorption is reduced to a few percent of the amount adsorbed at an untreated surface. The block copolymer adsorption route is less effective, mainly due to protein-induced desorption of the hydrophilizing agent. Bacterial adherence is also minimal when the PEI-PEG route is used. Branched PEGs are slightly less effective than linear PEGs of the same molecular weight. The difference in performance between linear and branched PEGs is discussed in terms of difference in entropy change when the hydrophilic surface-bound layer is compressed by an approaching protein. Branched PEGs, having smaller exclusion volumes and less freedom of motion, will lose less entropy on compression. The effects excerted on protein adsorption by PEG attached to a surface parallel its effect on particle mobility in electrophoresis. Similar molecular properties seem to be responsible for both protein and bacteria rejection and reduction of electrokinetic effects.
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| 50. |
- Holmberg, Krister, et al.
(författare)
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Surface modification of hydroxyapatite for dental plaque inhibition
- 1997
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Ingår i: Functional Polymers Syntheses and Applications. - : American Chemical Society (ACS). ; , s. 739-751
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Bokkapitel (refereegranskat)abstract
- Various types of surface treatments of hydroxyapatite have been investigated in order to obtain a material with low protein and bacterial adsorption characteristics. Since hydroxyapatite is seen as a model for tooth enamel, a procedure providing a surface with low tendency for biofouling would be of interest in vivo to prevent build-up of dental plaque. The paper summarizes surface modification work in the area, including treatments with proteins and polyelectrolytes, use of hydrophilic noncharged polymers, modification with silicones and fluorination. Particularly interesting in vitro results have been obtained with hydrophilic polymers, e.g. poly(alkylene oxides) and polysaccharides, carrying phosphate groups for anchoring to the mineral surface.
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