Mechanical analysis of cranial distractor attachment with three different resorbable fixation systems

Distraction osteogenesis (DO) has become increasingly popular to correct craniosynostosis. Disadvantages of DO include the secondary operation needed for device removal and titanium screw related dura injury. To reduce invasiveness of the secondary device removal operation and to overcome titanium-related problems, fixation of the cranial distractor with resorbable materials is a potential alternative. New resorbable fixation methods, such as ultrasound-activated pins (UAPs) or heat-activated pins (HAPs), allow faster attachment on thinner bone than conventional resorbable screws (CRSs) since tapping is not required. However, resorbable materials are designed to be attached with a resorbable plate, not with a titanium distractor. We evaluated the suitability of CRSs, HAPs and UAPs for the cranial distractor fixation in a laboratory setting with a mechanical testing machine. Fracture tests were conducted in two directions with respect to the longitudinal axis; vertical i.e. axial pull-out strength, and horizontal i.e. shear strength. Mean maximum pull-out strength for CRS, HAP and UAP was 48.9 N, 32.5 N and 14.7 N, respectively. Mean maximum shear strength for CRS, HAP and UAP was 40.8 N, 77.9 N and 38.9 N, respectively. According to our in vitro tests, the cranial distractor attachment with four CRSs or six HAPs per footplate would provide sufficient fixation stability. (C) 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Middle atmospheric ozone, nitrogen dioxide and nitrogen trioxide in 2002-2011: SD-WACCM simulations compared to GOMOS observations

Most of our understanding of the atmosphere is based on observations and their comparison with model simulations. In middle atmosphere studies it is common practice to use an approach, where the model dynamics are at least partly based on temperature and wind fields from an external meteorological model. In this work we test how closely satellite measurements of a few central trace gases agree with this kind of model simulation. We use collocated vertical profiles where each satellite measurement is compared to the closest model data. We compare profiles and distributions of O3, NO2 and NO3 from the Global Ozone Monitoring by Occultation of Stars instrument (GOMOS) on the Envisat satellite with simulations by the Whole Atmosphere Community Climate Model (WACCM). GOMOS measurements are from nighttime. Our comparisons show that in the stratosphere outside the polar regions differences in ozone between WACCM and GOMOS are small, between 0 and 6%. The correlation of 5-day time series show a very high 0.9-0.95. In the tropical region 10° S-10° N below 10hPa WACCM values are up to 20% larger than GOMOS. In the Arctic below 6 hPa WACCM ozone values are up to 20% larger than GOMOS. In the mesosphere between 0.04 and 1hPa the WACCM is at most 20% smaller than GOMOS. Above the ozone minimum at 0.01hPa (or 80km) large differences are found between WACCM and GOMOS. The correlation can still be high, but at the second ozone peak the correlation falls strongly and the ozone abundance from WACCM is about 60% smaller than that from GOMOS. The total ozone columns (above 50hPa) of GOMOS and WACCM agree within ±2% except in the Arctic where WACCM is 10% larger than GOMOS. Outside the polar areas and in the validity region of GOMOS NO2 measurements (0.3-37 hPa) WACCM and GOMOS NO2 agree within -5 to +25% and the correlation is high (0.7-0.95) except in the upper stratosphere at the southern latitudes. In the polar areas, where solar particle precipitation and downward transport from the thermosphere enhance NO2 abundance, large differences up to -90% are found between WACCM and GOMOS NO2 and the correlation varies between 0.3 and 0.9. For NO3, we find that the WACCM and GOMOS difference is between -20 and 5% with a very high correlation of 0.7-0.95. We show that NO3 values strongly depend on temperature and the dependency can be fitted by the exponential function of temperature. The ratio of NO3 to O3 from WACCM and GOMOS closely follow the prediction from the equilibrium chemical theory. Abrupt temperature increases from sudden stratospheric warmings (SSWs) are reflected as sudden enhancements of WACCM and GOMOS NO3 values

Comparison of 'shallow' and 'deep' junction architectures for MBE-grown InAs/GaAs quantum dot solar cells

We report on the fabrication of InAs/GaAs quantum dot solar cells with high open circuit voltage by molecular beam epitaxy. `Shallow' and `deep' junction architectures were compared. The highest open circuit voltage of 0.94 V was obtained for the `shallow' junction configuration. The open circuit voltage of InAs quantum dot solar cells decreased only by ~40 mV compared to GaAs reference cells for both junction architectures indicating high quality quantum dots. The open circuit voltage of InAs/GaAs quantum dot solar cells was also found to be dependent on the size of quantum dots

Treatment of compound tibia fracture with microvascular latissimus dorsi flap and the Ilizarov technique : A cross-sectional study of long-term outcomes

Background: Extensive compound tibial fractures present reconstructive challenges. The present study aimed to assess the outcomes of microvascular latissimus dorsi (LD) flap combined with the Ilizarov technique for extensive compound tibial fractures with bone loss and bone healing complications. Methods: Patient records were reviewed retrospectively. The Lower Extremity Functional Scale (LEFS), the Disabilities of the Arm, Hand and Shoulder (DASH), and the 15D health-related quality of life (HRQoL) instrument were applied. Results: Between 1989 and 2014, 16 patients underwent reconstruction with a microvascular LD flap and bone transport (11/16) or late bone lengthening (5/16). The mean clinical follow-up time was 6.6 (standard deviation (SD): 6.5) years. Three patients had minor complications requiring reoperation. Partial necrosis of one flap required late flap reconstruction in one case. Late bone grafting was used to enhance union in eight of 16 cases. The mean new bone gain was 3.8 cm (SD: 2.5). Overall, 11 patients completed the questionnaires in a mean of 22.3 years (SD: 2.4) after surgery. The main findings revealed a relatively good function of the reconstructed limb and good shoulder function. The mean HRQoL was comparable to that of an age-standardized sample of the general population. Conclusion: Segmental tibia transport and lengthening to correct limb length discrepancy do not compromise the microvascular muscle flap. Combined microvascular LD flap reconstruction and the Ilizarov technique can be used in treating acute compound tibial defects, pseudoarthrosis, and osteitis, all associated with significant amputation risk. Fair long-term functional outcomes and HRQoL are achieved when these combined techniques are used. (C) 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Health-related quality of life after oncological resection and reconstruction of the chest wall

Objectives: There is limited information of the health-related quality of life (HRQoL) after surgical treatment of chest wall tumors. This cross-sectional study aimed to assess long-term HRQoL after chest wall reconstruction following oncological resection. Methods: Seventy-eight patients having undergone chest wall tumor resection and reconstruction during 1997-2015 were invited to complete the 15D and QLQ-C30 HRQoL instruments. Results: Altogether, 55 patients (17 men and 38 women), with a mean (SD) age of 68 (14) years, completed the questionnaires (response rate 71%). Patients had been operated due to soft tissue sarcoma (n=16), advanced breast cancer (n=15), osteo- or chondrosarcoma (n=14), or other tumor (n=10). Median time after primary surgery was 66 (IQR 38, 141) months. The resection was full thickness in 29/55 cases and partial thickness in 26/55 cases. Chest wall reconstruction was required for 47/55 cases (85%). Reconstruction was performed using soft-tissue flap in eight cases, skeletal stabilizations with mesh or mesh-cement-mesh (sandwich method) in 15 cases, and skeletal stabilizations and soft-tissue flap in 24 cases. Patients' mean 15D score (0.878, SD 0.111) was comparable to that of the age- and gender-standardized general population (0.891, SD 0.041). Limitations in breathing and usual activities were noted. The QLQ-C30 cancer-specific HRQoL was 72 points (maximum 100). Scores in the QLQ-C30 Functional scales ranged from 78 (Physical) to 91 (Social). Conclusions: Long-term HRQoL in patients after chest wall reconstruction following oncological resection is fair and comparable to that of the general population. Limitations in breathing and usual activities can occur. (C) 2019 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Maksaetäpesäkkeiden leikkaushoito - missä menevät rajat?

Maksaetäpesäkekirurgia tarjoaa mahdollisuuden parantavaan hoitoon osalle levinnyttä kolorektaalisyöpää ja neuroendokriinista syöpää sairastavista potilaista. Potilasvalinta ja hoidon suunnittelu vaativat moniammatillista yhteistyötä maksakirurgin, gastrokirurgin, onkologin, gastroradiologin ja maksapatologin kesken. Suunnittelussa huomioidaan syöpätaudin käyttäytyminen, kasvainten sijainti maksassa, maksan toiminta ja potilaan yleissairaudet.</p

Force measurements during posterior calvarial vault osteodistraction : A novel measurement method

Posterior calvarial vault osteodistraction (PCVO) has become increasingly popular in the correction of craniosynostosis. When compared to cranioplasty, PCVO offers a shorter, less invasive operation, greater intracranial volume advancement and a lower rate of relapse. In general, distraction protocols are based primarily on clinical observations rather than systematic research. Faster distraction protocols may reduce complications. However, distraction protocols producing higher forces can increase complications. Thus, we need to understand these forces in order to improve distraction protocols and devices. We developed a force measurement method that can be used on PCVO devices. Here, we present preliminary data about the forces developed during PCVO. We measured the forces in four bicoronal craniosynostosis patients during PCVO. We observed a linear-like trend between the force increase and the distraction distance within distraction sessions. We also observed a step-wise force increase between distraction sessions and found that the distraction force relaxed rapidly shortly after the distraction session. The mean maximum pre distraction force for one distracter was 20.4 N, while the mean maximum end-distraction force for one distracter was 57.6 N. Our data suggests that current treatment protocols might be re-evaluated favouring shorter distraction distances and more frequent distraction sessions. (C) 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Retrieval of ozone profiles from GOMOS limb scattered measurements

The GOMOS (Global Ozone Monitoring by Occultation of Stars) instrument on board the Envisat satellite measures the vertical composition of the atmosphere using the stellar occultation technique. While the night-time occultations of GOMOS have been proven to be of good quality, the daytime occultations are more challenging due to weaker signal-to-noise ratio. During daytime GOMOS measures limb scattered solar radiation in addition to stellar radiation. In this paper we introduce a retrieval method that determines ozone profiles between 20–60 km from GOMOS limb scattered solar radiances. GOMOS observations contain a considerable amount of stray light at high altitudes. We introduce a method for removing stray light and demonstrate its feasibility by comparing the corrected radiances against those measured by the OSIRIS (Optical Spectrograph &amp; Infra Red Imaging System) instrument. For the retrieval of ozone profiles, a standard onion peeling method is used. The first comparisons with other data sets suggest that the retrieved ozone profiles in 22–50 km are within 10% compared with the GOMOS night-time occultations and within 15% compared with OSIRIS. GOMOS has measured about 350 000 daytime profiles since 2002. The retrieval method presented here makes this large amount of data available for scientific use