| 1. |
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| 2. |
- Taghavi, Hamidreza, 1981, et al.
(författare)
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Technical design of a new bone conduction implant (BCI) system
- 2015
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Ingår i: International Journal of Audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 54:10, s. 736-744
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The objective of this study is to describe the technical design and verify the technical performance of a new bone conduction implant (BCI) system. Design: The BCI consists of an external audio processor and an implanted unit called the bridging bone conductor. These two units use an inductive link to communicate with each other through the intact skin in order to drive an implanted transducer. Study sample: In this study, the design of the full BCI system has been described and verified on a skull simulator and on real patients. Results: It was found that the maximum output force (peak 107 dB re 1 N) of the BCI is robust for skin thickness range of 2-8 mm and that the total harmonic distortion is below 8% in the speech frequency range for 70 dB input sound pressure level. The current consumption is 7.5 mA, which corresponds to 5-7 days use with a single battery. Conclusions: This study shows that the BCI is a robust design that gives a sufficiently high output and an excellent sound quality for the hearing rehabilitation of indicated patients.
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| 3. |
- Altraja, Alan, et al.
(författare)
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Expression of laminins in the airways in various types of asthmatic patients: A morphometric study
- 1996
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Ingår i: American Journal of Respiratory Cell and Molecular Biology. - 1044-1549 .- 1535-4989. ; 15:4, s. 482-488
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Tidskriftsartikel (refereegranskat)abstract
- Laminins (Ln) are crucial in airway morphogenesis. Because they are able to interact with inflammatory cells, they are likely to participate in inflammation accompanied by airway structural remodeling in asthma. Taking biopsies and using immunohistochemistry and quantitative image analysis, we characterized the distribution of Ln chains alpha 1, alpha 2, and beta 2 in the bronchial mucosa of patients with seasonal (n = 17), early occupational (n = 8), and chronic asthma (n = 16) for comparison with that of normal controls (n = 8). In all asthmatic patients, both Ln chains alpha 1 and beta 2 were confined to the superficial margin of the basement membrane (BM), blood vessels, and smooth muscle. The thickness of Ln beta 2 expression in BM was significantly greater in patients with chronic (1.9 +/- 0.1 microns; P < 0.001) and occupational asthma (1.7 +/- 0.1 microns; P < 0.05) than in controls (0.4 +/- 0.3 microns). Only in patients with occupational asthma was the thickness of the Ln alpha 1 layer (2.3 +/- 0.2 microns; mean +/- SEM) significantly different from that in controls (1.4 +/- 0.5 microns; P < 0.05). There was no immunoreactivity for the Ln alpha 2 chain in controls or patients with mild asthma, but in clinically severe chronic asthma we found a discontinuous staining along the epithelial margin of the BM. Since Ln chains alpha 2 and beta 2 appear to function only during morphogenesis, increased expression of these Ln chains in adult asthma patients suggests accelerated tissue turnover in the airways, possibly as a result of airway inflammation in asthma.
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| 4. |
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| 5. |
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| 6. |
- Bengtsson, Bo, et al.
(författare)
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Residential Mobility and Housing Policy : Continuity and Change in the Swedish Housing Regime
- 2019
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Ingår i: Investigating Spatial Inequalities: Mobility, Housing and Employment in Scandinavia and South-East Europe. - : Emerald Group Publishing Limited. - 9781789739428 ; , s. 139-158
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Bokkapitel (refereegranskat)abstract
- Transaction costs, responsive housing supply, rent controls, tenant protection, and access to credit affect residential mobility these different parts of housing policy are included in what has been defined as housing regimes, which embrace regulations, laws, norms, and ideology as well as economic factors. In this chapter, we investigate how these regimes change by using institutional theories of path dependence. We use Sweden as an example and study three Swedish housing market reforms during the past decades that may have affected residential mobility, each related to one of the main institutional pillars of housing provision: tenure legislation, taxation, and finance. More precisely, we study the development of the rental regulation since the late 1960s, the tax reform in 1991, and the new reforms on mortgages since 2010. What caused these reforms? What were the main mechanisms behind them, and why did they occur at the time they did? We argue, besides affecting residential mobility, these reforms have the common feature of including interesting elements of path dependence and forming critical junctures that have led the development on to a new path. Institutions of tenure legislation, housing finance, and taxation are often claimed to have effects on residential mobility. Although they are seldom designed with the explicit aim of supporting (or counteracting) residential mobility, they may sometimes do so as more or less unintended consequences.
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| 7. |
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| 8. |
- Bergquist, Jonas, et al.
(författare)
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Mass spectrometry of proteins - Uppsala perspectives on past and present : Paper in honor of Prof. Peter Roepstorff's 65th birthday
- 2007
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Ingår i: International Journal of Mass Spectrometry. - : Elsevier BV. - 1387-3806 .- 1873-2798. ; 268:2-3, s. 73-82
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Tidskriftsartikel (refereegranskat)abstract
- The development of biological mass spectrometry has been rapid in the past three to four decades. In particular, the possibility to detect and identify peptides and proteins from biologically and medically relevant samples has revolutionized life sciences. The development has gone from a stage where the detection of insulin in a mass spectrum was a major event to one in which the recording of mass spectra with more than 104 resolved and calibrating peaks in each spectrum is a routine task.In this paper, the evolution of protein mass spectrometry will be discussed from the Uppsala horizon with special emphasis on the unique coupling between ion induced desorption of biomolecules and ion track physics.
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| 9. |
- Bergström, Martin, et al.
(författare)
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Interventions in Foster Family Care: A Systematic Review
- 2020
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Ingår i: Research on social work practice. - : SAGE Publications. - 1049-7315 .- 1552-7581. ; 30:1, s. 3-18
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Foster family care is associated with adverse short- and long-term consequences for the child. A systematic review was conducted on interventions for foster children and foster careers. Method: A comprehensive search process was used to find eligible interventions evaluated in randomized controlled trials or quasi-experimental studies. The quality of studies was assessed with GRADE, and effects were synthesized using meta-analytic methods. Results: In all, 28 publications of 18 interventions, including 5,357 children, were identified. Only three specific interventions had sufficient confidence of evidence. No study had examined tools for foster parent selection nor had evaluated preservice programs related to outcomes. Discussion: These analyses provide new insights and hope into the field of systematic interventions in foster care. The overall results indicate that it is possible to improve eight outcomes but cannot point out which programs are superior. Ethically, social care organizations should systematically collect knowledge about effects and side effects.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Bjurulf, Bo, et al.
(författare)
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Riksdagsvalet 1991
- 1994
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Ingår i: Väljare i kommunalvalet. Om missnöje, misstroende och politisk kultur. - 9171505474
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Abstract is not available
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| 15. |
- Brandt, Anders, et al.
(författare)
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Properties of bone conduction hearing
- 2006
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Ingår i: XXIV International Modal Analysis Conference, St. Louis, Missouri.
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Konferensbidrag (refereegranskat)
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| 16. |
- Brandt, Anders, et al.
(författare)
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Properties of Bone Conduction Hearing
- 2006
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Konferensbidrag (refereegranskat)abstract
- Bone conduction sound, the transmission of sound as vibrations in the skull bone, is used in several areas, forexample for hearing aids, in audiometry, and in communication systems. The bone-anchored hearing aid (BAHA)has been commercially available for many years. This device utilizes titanium screws attached to the skull bonepenetrating the soft tissues thus providing a rigid attachment to the skull bone. Subjects equipped with suchtitanium screws have proven important for investigation of bone conducted sound and in the present paper anoverview of some results from different studies on such patients is given. Included are results from investigationsof resonance frequencies, propagation delays, and transcranial (cross-skull) attenuation.
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| 17. |
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| 18. |
- Carlsson, L, et al.
(författare)
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Common cancer-related symptoms among GP patients - Opportunistic screening in primary health care
- 2001
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Ingår i: Scandinavian Journal of Primary Health Care. - 0281-3432 .- 1502-7724. ; 19:3, s. 199-203
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Tidskriftsartikel (refereegranskat)abstract
- Objective-To study the occurrence of symptoms related to the five most common forms of cancer among patients regularly visiting primary care. To estimate the proportion of symptoms needing GP examination, and the number of tumours thus diagnosed. Design-Patients with some form of non-malignant chronic disease received a letter with information about cancer-related symptoms along with an invitation to regular check-up. The letter described the most common symptoms of breast, colorectal, lung, prostate and skin cancers. Setting-12 health centres in Kalmar County, Sweden. Subjects-5200 patients aged over 40 years. Results-One patient in 13 reported cancer-related symptoms to the GP. Women reported more symptoms than men, and almost half of them had had symptoms at previous check-ups. The GP was able to explain 7 out of 10 patients' symptoms directly. When other symptoms were examined, 8 cancers were diagnosed as well as 6 pre-malignant tumours, corresponding to 3 tumour diagnoses per 1000 check-ups. Conclusion-While attending regular check-ups, patients may not report symptoms which cause anxiety and sometimes indicate serious diseases. It is possible to widen the perspective and link both primary and secondary prevention of certain cancers to the check-up.
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| 19. |
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| 20. |
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| 21. |
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| 22. |
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| 23. |
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| 24. |
- Clemente, Francesco, et al.
(författare)
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Touch and Hearing Mediate Osseoperception
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Osseoperception is the sensation arising from the mechanical stimulation of a bone-anchored prosthesis. Here we show that not only touch, but also hearing is involved in this phenomenon. Using mechanical vibrations ranging from 0.1 to 6 kHz, we performed four psychophysical measures (perception threshold, sensation discrimination, frequency discrimination and reaction time) on 12 upper and lower limb amputees and found that subjects: consistently reported perceiving a sound when the stimulus was delivered at frequencies equal to or above 400 Hz; were able to discriminate frequency differences between stimuli delivered at high stimulation frequencies (similar to 1500 Hz); improved their reaction time for bimodal stimuli (i.e. when both vibration and sound were perceived). Our results demonstrate that osseoperception is a multisensory perception, which can explain the improved environment perception of bone-anchored prosthesis users. This phenomenon might be exploited in novel prosthetic devices to enhance their control, thus ultimately improving the amputees' quality of life.
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| 25. |
- Cornell, Ann, 1962-, et al.
(författare)
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Anodic Reactions in the Chlorate Process
- 2001. - 1
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Ingår i: Energy and Electrochemical Processes for a Cleaner Environment. - Pennington, New Jersey, USA : The Electrochemical Scoiety, Inc.. - 1566773563 ; , s. 117-128
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Bokkapitel (refereegranskat)
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| 26. |
- Cornell, Ann, et al.
(författare)
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Ruthenium-based dimensionally stable anode in chlorate electrolysis - Effects of electrolyte composition on the anode potential
- 2003
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 150:1, s. D6-D12
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Tidskriftsartikel (refereegranskat)abstract
- In this work the anodic reactions taking place on a dimensionally stable anode (DSA) in chlorate electrolyte have been investigated. Rotating disk electrodes were made from commercial RuO2-catalyzed DSAs and studied in steady-state polarization measurements, mainly IR-corrected polarization curves. Effects of varying pH and electrolyte concentrations of chloride, chlorate, chromium(VI), hypochlorite (ClO- + ClOH) as well as mass transport were studied. The kinetics for the chlorine evolution reaction, with a Tafel slope of 40 mV/decade of current, was not dependent on pH in the region 2-8, at potentials lower than 1.2 V vs. Ag/AgCl. The slope of the polarization curves increased at about 1.2 V vs. Ag/AgCl, a pH-dependent bend not due to mass-transport limitations in the electrolyte. At a pH of 6.5, typical for the chlorate process, oxygen evolution is an important side reaction favored by the dichromate buffer and by increased mass transport, both keeping down the pH at the anode. In the chlorine evolution region the potentials increased when adding Cr(VI) to the electrolyte, whereas no major effect was seen from additions of NaClO. (C) 2002 The Electrochemical Society.
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| 27. |
- Cornell, Ann, et al.
(författare)
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Ruthenium based DSA in chlorate electrolysis–critical anode potential and reaction kinetics
- 2003
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Ingår i: Electrochimica Acta. - 0013-4686 .- 1873-3859. ; 48:5, s. 473-481
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Tidskriftsartikel (refereegranskat)abstract
- Ruthenium based DSA®s have been investigated in chlorate electrolyte using rotating discs made from commercial electrodes. Measurements of the voltammetric charge, q*, and of iR-corrected polarisation curves up to current densities of 40 kA/m2 were recorded on new anodes and on aged anodes from 3 years of production in a chlorate plant. Anodic polarisation curves in chloride containing electrolytes bend towards a higher slope at approximately 1.2 V versus Ag/AgCl, likely due to oxidation of ruthenium. The potential and current density at which the curves bend have been defined as the critical potential, Ecr, and the critical current density, icr. New anodes that operate at a relatively high potential, >Ecr, obtain an increase in real surface area and thereby a decrease in anode potential and in the selectivity for oxygen formation during the first months of operation. Experiments at constant ionic strength under chlorate process conditions showed that Ecr decreased with increasing chloride concentration with a factor of −0.09 V/log Cl−, whereas icr increased with increasing chloride concentration. The chlorine evolution reaction was of the first order with respect to chloride concentration. A possible reaction mechanism for chlorine formation is suggested.
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| 28. |
- Eeg-Olofsson, Måns, 1967, et al.
(författare)
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BCI-bone conduction implant.
- 2013
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Ingår i: The Fourth International Symposium on Bone Conduction Hearing – Craniofacial Osseointegration. Newcastle, UK.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 29. |
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| 30. |
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| 31. |
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| 32. |
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| 33. |
- Eeg-Olofsson, Måns, 1967, et al.
(författare)
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Evaluation of bone tissue formation in a flat surface attachment of a Bone Conduction Implant - A pilot study in a sheep model
- 2014
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Ingår i: Audiology & Neurotology Extra. - : S. Karger AG. - 1664-5537. ; 4:3, s. 62-76
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Tidskriftsartikel (refereegranskat)abstract
- The Bone Conduction Implant (BCI) is a new bone conduction hearing device implanted under intact skin. The transducer has a flat direct contact to the mastoid part of the temporal bone and no screws are used. The sound signal is transmitted from the external audio processor to the implant by means of magnetic induction. In this study, osseointegration of a flat passive BCI transducer dummy in sheep skulls was assessed using quantitative and qualitative histology as well as Cone Beam Computed Tomography (CBCT) and Computed Tomography (CT). The histology results were also related to the mechanical properties of the bone to implant interface. Eight months after the surgical implantation, histology sections of the bone close to the implant showed bone remodelling, compact bone and some degree of osseointegration. The histological findings corresponded well to the mechanical measurements indicating stiffer bone close to the implant, and unaffected skull vibration transmission. Neither CBCT nor CT had enough resolution to visualize the bone to implant interface in detail. In this study, using an animal model, it is shown that a flat implant in contact with bone, can be a feasible method for efficient vibration transmission to the skull bone.
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| 34. |
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| 35. |
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| 36. |
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| 37. |
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| 38. |
- Eeg-Olofsson, Måns, 1967, et al.
(författare)
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Transmission of bone conducted sound – Correlation between hearing perception and cochlear vibration
- 2013
-
Ingår i: Hearing Research. - : Elsevier. - 0378-5955 .- 1878-5891. ; 306, s. 11-20
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Tidskriftsartikel (refereegranskat)abstract
- The vibration velocity of the lateral semicircular canal and the cochlear promontory was measured on 16 subjects with a unilateral middle ear common cavity, using a laser Doppler vibrometer, when the stimulation was by bone conduction (BC). Four stimulation positions were used: three ipsilateral positions and one contralateral position. Masked BC pure tone thresholds were measured with the stimulation at the same four positions. Valid vibration data were obtained at frequencies between 0.3 and 5.0 kHz. Large intersubject variation of the results was found with both methods. The difference in cochlear velocity with BC stimulation at the four positions varied as a function of frequency while the tone thresholds showed a tendency of lower thresholds with stimulation at positions close to the cochlea. The correlation between the vibration velocities of the two measuring sites of the otic capsule was high. Also, relative median data showed similar trends for both vibration and threshold measurements. However, due to the high variability for both vibration and perceptual data, low correlation between the two methods was found at the individual level. The results from this study indicated that human hearing perception from BC sound can be estimated from the measure of cochlear vibrations of the otic capsule. It also showed that vibration measurements of the cochlea in cadaver heads are similar to that measured in live humans.
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| 39. |
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| 40. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
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Bone Conduction Stimulated VEMP Using the B250 Transducer
- 2021
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Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 14, s. 225-237
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Bone conduction (BC) stimulation is rarely used for clinical testing of vestibular evoked myogenic potentials (VEMPs) due to the limitations of conventional stimulation alternatives. The aim of this study is to compare VEMP using the new B250 transducer with the Minishaker and air conduction (AC) stimulation. Methods: Thirty normal subjects between 20 and 37 years old and equal gender distribution were recruited, 15 for ocular VEMP and 15 for cervical VEMP. Four stimulation conditions were compared: B250 on the mastoid (FM); Minishaker and B250 on the forehead (FZ); and AC stimulation using an insert earphone. Results: It was found that B250 at FM required a statistically significant lower hearing level than with AC stimulation, in average 41 dB and 35 dB lower for ocular VEMP and cervical VEMP, respectively, but gave longer n10 (1.1 ms) and n23 (1.6 ms). No statistical difference was found between B250 at FM and Minishaker at FZ. Conclusion: VEMP stimulated with B250 at FM gave similar response as the Minishaker at FZ and for a much lower hearing level than AC stimulation using insert earphones.
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| 41. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
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Electro-acoustic performance of the new bone vibrator Radioear B81: A comparison with the conventional Radioear B71
- 2015
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Ingår i: International Journal of Audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 54:5, s. 334-340
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The objective is to evaluate the electro-acoustic performance of a new audiometric bone vibrator, the B81 from Radioear Corporation, USA. Comparison will be made with the widely used B71 which has well-known limitations at low frequencies. Design: The B81 is based on the balanced electromagnetic separation transducer (BEST) principle where static forces are counterbalanced so that nonlinear distortion forces are reduced and maximum hearing levels can be increased. Study sample: Maximum hearing level, total harmonic distortion (THD), frequency response, and electrical impedance were measured for six devices of each bone vibrator type on an artificial mastoid. Results: It was found that B81 reaches 10.7-22.0 dB higher maximum (@ THD. 6% or V-in. 6 V-RMS) hearing levels than B71 for frequencies below 1500 Hz, and had significantly lower THD up to 1000 Hz. There was no statistically significant difference between their frequency response, except a deviation at the mid frequencies (alpha = 0.01) where B81 was more efficient and the electrical impedances were practically the same. Conclusions: In general, B81 had an improved electro-acoustic performance compared to B71 and is compatible with same audiometers. In particular, B81 allows for sensorineural hearing loss to be measured at considerably higher hearing levels than with B71 below 1500 Hz.
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| 42. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
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Electroacoustic evaluation of the bone conduction transducer B250 for vestibular and hearing diagnostics in comparison with Radioear B71 and B81
- 2024
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Ingår i: International Journal of Audiology. - 1499-2027 .- 1708-8186. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The objective is to evaluate the electroacoustic performance of the B250 transducer and to compare it with the two most widely used audiometric transducers B71 and B81. Design: The electroacoustic performance was evaluated in terms of sensitivity level, distortion, maximum hearing level and electrical impedance. Study sample: Six B250 prototype transducers were evaluated and compared with published data of B71 and B81 together with complementary measurements of maximum hearing level at 125 Hz and phase of electrical impedance. Differences in reference equivalent threshold vibratory force levels were estimated by comparing hearing threshold measurements of 60 healthy ears using B81 and B250. Results: B250 has approximately 27 dB higher sensitivity levels than both B71 and B81 at 250 Hz and can generate higher maximum hearing level at low frequencies: 11.8 to 35.8 dB (125–1000 Hz) higher than B71, and 1.4 to 18.6 dB (125–750 Hz) higher than B81. The maximum average difference in reference threshold force levels was 13.5 ± 8.7 dB higher for B250 at 250 Hz compared to B81. Conclusions: B250 can produce higher output force with less distortion than B71 and B81, especially at 125 and 250 Hz, which could possibly improve low frequency investigations of the audio-vestibular system.
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| 43. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
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Electroacoustic evaluation of the bone conduction transducer B250 for vestibular and hearing diagnostics in comparison with Radioear B71 and B81
- 2024
-
Ingår i: INTERNATIONAL JOURNAL OF AUDIOLOGY. - 1499-2027 .- 1708-8186.
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveThe objective is to evaluate the electroacoustic performance of the B250 transducer and to compare it with the two most widely used audiometric transducers B71 and B81.DesignThe electroacoustic performance was evaluated in terms of sensitivity level, distortion, maximum hearing level and electrical impedance.Study sampleSix B250 prototype transducers were evaluated and compared with published data of B71 and B81 together with complementary measurements of maximum hearing level at 125 Hz and phase of electrical impedance. Differences in reference equivalent threshold vibratory force levels were estimated by comparing hearing threshold measurements of 60 healthy ears using B81 and B250.ResultsB250 has approximately 27 dB higher sensitivity levels than both B71 and B81 at 250 Hz and can generate higher maximum hearing level at low frequencies: 11.8 to 35.8 dB (125-1000 Hz) higher than B71, and 1.4 to 18.6 dB (125-750 Hz) higher than B81. The maximum average difference in reference threshold force levels was 13.5 +/- 8.7 dB higher for B250 at 250 Hz compared to B81.ConclusionsB250 can produce higher output force with less distortion than B71 and B81, especially at 125 and 250 Hz, which could possibly improve low frequency investigations of the audio-vestibular system.
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| 44. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
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Magnetic resonance imaging investigation of the bone conduction implant - a pilot study at 1.5 Tesla.
- 2015
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Ingår i: Medical devices (Auckland, N.Z.). - 1179-1470. ; 8, s. 413-23
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this pilot study was to investigate if an active bone conduction implant (BCI) used in an ongoing clinical study withstands magnetic resonance imaging (MRI) of 1.5 Tesla. In particular, the MRI effects on maximum power output (MPO), total harmonic distortion (THD), and demagnetization were investigated. Implant activation and image artifacts were also evaluated.
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| 45. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
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MRI Induced Torque and Demagnetization in Retention Magnets for a Bone Conduction Implant
- 2014
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Ingår i: IEEE Transactions on Biomedical Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9294 .- 1558-2531. ; 61:6, s. 1887-1893
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Tidskriftsartikel (refereegranskat)abstract
- Performing magnetic resonance imaging (MRI) examinations in patients who use implantable medical devices involve safety risks both for the patient and the implant. Hearing implants often use two permanent magnets, one implanted and one external, for the retention of the external transmitter coil to the implanted receiver coil to achieve an optimal signal transmission. The implanted magnet is subjected to both demagnetization and torque, magnetically induced by the MRI scanner. In this paper, demagnetization and a comparison between measured and simulated induced torque is studied for the retention magnet used in a bone conduction implant (BCI) system. The torque was measured and simulated in a uniform static magnetic field of 1.5 T. The magnetic field was generated by a dipole electromagnet and permanent magnets with two different types of coercive fields were tested. Demagnetization and maximum torque for the high coercive field magnets was 7.7% +/- 2.5% and 0.20 +/- 0.01 Nm, respectively and 71.4% +/- 19.1% and 0.18 +/- 0.01 Nm for the low coercive field magnets, respectively. The simulated maximum torque was 0.34 Nm, deviating from the measured torque in terms of amplitude, mainly related to an insufficient magnet model. The BCI implant with high coercive field magnets is believed to be magnetic resonance (MR) conditional up to 1.5 T if a compression band is used around the skull to fix the implant. This is not approved and requires further investigations, and if removal of the implant is needed, the surgical operation is expected to be simple.
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| 46. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
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Robustness and lifetime of the bone conduction implant - a pilot study
- 2019
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Ingår i: Medical Devices: Evidence and Research. - 1179-1470. ; 12, s. 89-100
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The objective of this study was to develop methods for evaluating the mechanical robustness and estimating the lifetime of the novel bone conduction implant (BCI) that is used in a clinical study. The methods are intended to be applicable to any similar device. Materials and methods: The robustness was evaluated using tests originally developed for cochlear implants comprising a random vibration test, a shock test, a pendulum test, and an impact test. Furthermore, magnetically induced torque and demagnetization during magnetic resonance imaging at 1.5 T were investigated using a dipole electromagnet. To estimate the lifetime of the implant, a long-term age-accelerated test was performed. Results: Out of all the tests, the pendulum and the impact tests had the largest effect on the electro-acoustic performance of the BCI implant, even if the change in performance was within acceptable limits (< 20%). In comparison with baseline data, the lower and higher resonance peaks shifted down in frequency by 13% and 18%, respectively, and with a loss in magnitude of 1.1 and 2.0 dB, respectively, in these tests. Conclusion: A complete series of tests were developed, and the BCI passed all the tests; its lifetime was estimated to be at least 26 years for patients who are using the implant for 12 hours on a daily basis.
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| 47. |
- Fredén Jansson, Karl-Johan, 1988, et al.
(författare)
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Vibrotactile Thresholds on the Mastoid and Forehead Position of Deaf Patients Using Radioear B71 and B81
- 2017
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Ingår i: Ear and Hearing. - 1538-4667 .- 0196-0202. ; 38:6, s. 714-723
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The main objective of this study was to measure the vibrotactile thresholds on the mastoid process and forehead positions using patients with bilateral deafness and to compare the results from the two bone conduction vibrators Radioear B71 and B81. Design: There is a possibility that the vibrotactile sensation on the skin makes it difficult to discriminate between sound and vibration. The risk is highest for patients who have bone conduction hearing thresholds in proximity to or worse than their vibrotactile thresholds. All measurements were performed similar to regular bone conduction threshold testing using an audiometer-driven bone conduction vibrator and pulsed warble tones, but the patients were instructed to respond only when feeling vibrations of the bone conduction vibrator instead of when hearing sound. Both the posterior forehead position and the mastoid process position on the temporal bone were tested for comparative reasons. In total, 16 patients participated in the study, 31% females and 69% males of age 29 to 77 years. All subjects were cochlear implant recipients, either uni-or bilaterally implanted. They were selected based on their audiogram data showing unmeasurable unaided hearing. Results: The force level at which the vibrotactile thresholds were reached, increased with frequency from 125 up to 500 Hz, but remained constant for higher frequencies up to 2 kHz. A statistically significant difference was found between the 2 devices at 125 Hz at both the mastoid process and forehead position, where the vibrotactile threshold seem to be more sensitive for B71, possibly due to contribution of distortion components. There was no statistically significant difference in vibrotactile thresholds between the mastoid process and forehead position in absolute values (force level in dB re 1 mu N), but in terms of hearing levels (dB HL) there was an average difference of 10 and 9 dB for B71 and B81, respectively. Conclusions: The results indicate that the vibrotactile thresholds can be confounded with bone conduction hearing thresholds measurements up to 500 Hz when using a standard audiometer and in particular when measuring on the forehead position.
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| 48. |
- Furebring, Mia, et al.
(författare)
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Expression of the C5a receptor (CD88) on granulocytes and monocytes in patients with severe sepsis
- 2002
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Ingår i: Critical Care. - 1364-8535 .- 1466-609X. ; 6:4, s. 363-370
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Treatment of patients with severe sepsis with agents antagonising the effects of C5a has been proposed based on beneficial effects in animal experiments and in vitro studies demonstrating upregulation of the C5a receptor (CD88) on granulocytes by endotoxin. MATERIALS AND METHODS: CD88 expression on leukocytes from 12 patients with severe sepsis or septic shock was analysed by flow cytometer, and serum complement factors C3a and C5b-9 were measured by enzyme immunoassay techniques. RESULTS: The granulocyte CD88 expression on day 1 was lowered (36; range, 2-59) in comparison with controls (63; range, 25-88) (P < 0.001), despite complement activation, while the monocyte CD88 expression was unchanged. The receptor reduction correlated significantly to the APACHE II score (r2 = 0.35, P < 0.05). The recovery of CD88 expression was slow. DISCUSSION: In contrast to the findings in animals, it is concluded that granulocyte CD88 expression is reduced at the time when the diagnosis of severe sepsis or septic shock can clinically be made. The reason for this needs further investigation but it may be due to a previous complement activation or to cytokine effects.
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