Getting magnetocaloric materials into good shape: Cold-working of La(Fe, Co, Si)13 by powder-in-tube-processing

The powder-in-tube (PIT) technology was applied to La(Fe, Co, Si)13 powder cladded by a thin seamless austenitic steel jacket. Wires appear to be promising in the search for alternative regenerator geometries, since they offer various possibilities of arrangements allowing to optimise heat transfer and pressure loss within the boundaries set by parallel plate and sphere beds. Here, pre-alloyed La(Fe, Co, Si)13 powder was filled in a AISI 316L austenitic steel tube and swaged to wires with an outer diameter of 1 mm. By mechanical deformation, the steel jacket thickness was reduced to about 100 μm surrounding the magnetocaloric core. A post-annealing of only 10 min at 1050 °C is sufficient to form the magnetocaloric NaZn13-type phase resulting in an entropy change close to the value of a pure reference sample. The presented technology is not limited to La(Fe, Co, Si)13/steel combination but can be extended to material pairs involving wire core materials with a first order transition, such as Fe2P-type or Heusler alloys

Repeatability of nerve fiber layer thickness measurements in patients with glaucoma and without glaucoma using spectral-domain and time-domain OCT

Background: The aim of this work is to assess the repeatability of spectral-domain-OCT (SD-OCT) retinal nerve fiber layer thickness (RNFL) thickness measurements in a non-glaucoma group and patients with glaucoma and to compare these results to conventional time-domain-OCT (TD-OCT). Methods: In a prospective, comparative, observational case-control study, 50 eyes of 25 non-glaucoma and 22 eyes of 11 patients with primary open angle glaucoma (POAG) were included. SD-OCT and TD-OCT circle scans were centered on the optic disc. In each eye, OCT scans were performed three times by two independent observers. RNFL thickness was measured in four quadrants around the optic disc. In addition, the overall mean RNFL thickness was assessed. Intraclass correlation coefficients (ICC) and coefficients of variation (COV) were calculated. Inter-observer and inter-OCT repeatability was visualized by using Bland-Altman analysis. Results: Intra-observer repeatability for TD- OCT was good with an ICCmean RNFL thickness of 0.939 in non-glaucomas and 0.980 in glaucomatous eyes. For SD-OCT, intra-observer repeatability was higher with an ICC of 0.989 for non-glaucomas and 0.997 for glaucomatous eyes. COVs for TD-OCT ranged from 2.9-7.7% in non-glaucomas and from 6.0-13.3% in glaucoma patients. COVs for SD-OCT ranged from 0.3-1% in non-glaucomas and from 0.9-2.3% in glaucomatous eyes. COVs were influenced by various factors. In the glaucoma group, COVs were significantly higher (p < 0.001) compared to the non-glaucoma group. COVs increased by a mean of 5.1% when TD-OCT was used instead of SD-OCT (p < 0.001). Conclusions: SD-OCT RNFL thickness measurements in healthy volunteers and glaucoma patients showed good intra- and inter-observer repeatability. Especially in glaucomatous eyes, repeatability of SD-OCT was superior to TD-OC

Rates of glaucomatous visual field change before and after transscleral cyclophotocoagulation: a retrospective case series

BACKGROUND: The primary goal of glaucoma treatment is to lower and control intraocular pressure (IOP) and thereby prevent functional deterioration. For glaucomas that are refractory to medical and incisional surgical therapies, transscleral diode cyclophotocoagulation (TCP) is a well-established procedure to effectively decrease IOP. This study investigated rates of visual field (VF) change in patients with glaucoma before and after TCP. METHODS: This retrospective case series investigated rates of VF changes in glaucoma patients before and after they underwent TCP. At least four VF examinations were required, two before and two after surgery. VF examinations were performed using standard automated perimetry and rates of change were calculated by linear regression analysis of mean deviation (MD) values measured over time. RESULTS: A total of 46 eyes of 43 patients were included and followed on average 3.6 years before and 2.1 years after TCP. 67 % of the eyes showed further progression of glaucoma following surgery. Mean preoperative MD change was -0.21 dB/year (SE = 0.08, 95 % CI [-0.06, -0.37]). Postoperatively the mean change was -0.26 dB/year (SE = 0.22 95 % CI [0.38, -0.48]) which results in a difference between pre- and postoperative MD rate of 0.05 dB/year (p = 0.824). The mean MD value was worse after surgery and dropped by 1.73 dB (SE = 0.58, 95 % CI [-0.59, -2.87], p = 0.003). Intraocular pressure (IOP) decreased from 23.2 mmHg (SD = 4.67) before TCP to 14.3 mmHg (SD = 3.17) after TCP (p < 0.001). For each 1 mmHg of IOP reduction after surgery, postoperative rate of VF loss decreased by 0.15 dB/year. CONCLUSION: Rates of glaucomatous visual field loss did not significantly change after TCP and the majority of the eyes showed further progression of glaucoma after surgery. Mean MD value was considerably lower after TCP

Flexible development of location-based mobile augmented reality applications with AREA

Mobile applications have garnered a lot of attention in the last years. The computational capabilities of mobile devices are the mainstay to develop completely new application types. The provision of augmented reality experiences on mobile devices paves one alley in this feld. For example, in the automotive domain, augmented reality applications are used to experience, inter alia, the interior of a car by moving a mobile device around. The device’s camera then detects interior parts and shows additional information to the customer within the camera view. Another application type that is increasingly utilized is related to the combination of serious games with mobile augmented reality functions. Although the latter combination is promising for many scenarios, technically, it is a complex endeavor. In the AREA (Augmented Reality Engine Application) project, a kernel was implemented that enables location-based mobile augmented reality applications. Importantly, this kernel provides a fexible architecture that fosters the development of individual location-based mobile augmented reality applications. The work at hand shows the fexibility of AREA based on a developed serious game. Furthermore, the algorithm framework and major features of it are presented. As the conclusion of this paper, it is shown that mobile augmented reality applications require high development eforts. Therefore, fexible frameworks like AREA are crucial to develop respective applications in a reasonable time

Selektive Lasertrabekuloplastik bei Patienten unter maximaler Lokaltherapie: eine retrospektive Analyse

Zusammenfassung: Hintergrund: Hauptziel der Glaukomtherapie ist nach wie vor die erfolgreiche Augendrucksenkung. Ziel dieser retrospektiven Studie war es, die Wirksamkeit der selektiven Lasertrabekuloplastik (SLT) bei Patienten unter maximaler Augendruck senkender Therapie zu untersuchen. Besonderes Augenmerk wurde in der Analyse darauf gelegt, ob präoperativ bekannte Faktoren einen Einfluss auf den IOD-senkenden Effekt haben. Material und Methode: Inkludiert wurden Patienten mit der Diagnose einer okulären Hypertension oder eines Offenwinkelglaukoms (primäres Offenwinkelglaukom, Pseudoexfoliationsglaukom, Pigmentdispersionsglaukom und Normaldruckglaukom), die im Zeitraum von 3/2008 bis 12/2010 aufgrund unzureichender Drucksenkung unter maximaler Lokaltherapie einer SLT unterzogen wurden und die einen Nachbeobachtungszeitraum von mindestens 3Monaten hatten. Die Datenanalyse erfolgte präoperativ, sowie einen Tag, einen Monat und drei Monate nach SLT und dann dreimonatlich bis zu 2,5 Jahre. Hauptmessparameter waren Ausmaß der IOD-Senkung sowie Erfolgsraten (³ 20% Augendruck-Senkung). Eine Re-SLT wurde nicht als Misserfolg gewertet. Resultate: Einhunderteinunddreißig Augen von 98 Patienten (58 Frauen, mittleres Alter 71,6 ± 11,2 Jahre, mittlerer Nachbeobachtungszeitraum 1,05 ± 0,67 Jahre) wurden inkludiert. Mittlerer Augendruck vor SLT war 19,6 ± 4,9mmHg. Bis 1,75 Jahre nach SLT war der Augendruck stets signifikant reduziert (16,6 ± 3,6; p = 0,044). Bis 2 Jahre nach SLT hatten Patienten mit höherem Ausgangs-Augendruck eine signifikant stärkere Drucksenkung (R2  = 0,358; p = 0,009). Es gab keinen signifikanten Unterschied in der Überlebensanalyse sowohl zwischen phaken bzw. pseudophaken Patienten als auch zwischen Patienten mit bzw. ohne Prostaglandintherapie (p = 0,671 und p = 0,994). Zwölf Augen hatten eine zweite SLT (mittlere Zeit bis zur Re-SLT 1,03 ± 0,55 Jahre). Fünfzehn Augen benötigten eine weitere Augendruck senkende Operation (mittlere Zeit bis zum Versagen der SLT 0,84 ± 0,52 Jahre). Schlussfolgerung: SLT kann auch bei Patienten unter maximaler Lokaltherapie noch eine signifikante Drucksenkung bewirken, wobei das Ausmaß der Drucksenkung über die Zeit abnimmt. Die Augendruck senkende Wirkung ist bei Patienten mit höherem präoperativen Augendruck stärker ausgepräg

Outcome of Pediatric Cataract Surgeries in a Tertiary Center in Switzerland

Purpose. To determine and to analyze the outcome of pediatric cataract surgery. Methods. A retrospective chart review of individuals aged up to 10 years who underwent cataract surgery between January 1, 2004, and December 31, 2014, at the UniversityHospital Zurich, Switzerland. Results. 63 children (94 affected eyes) with bilateral (68/94) or unilateral (26/94) cataract were identified. Surgery was performed at a median age of 1.5 months (IQR: 1.3–2.6 months) for the aphakic group (45/94) and of 50.7 months (IQR: 38.0–78.4 months) for the IOL group (49/94). At the last follow-up visit (median 31.1 months, IQR: 18.4–50.2 months), visual acuity was better in bilateral than in unilateral cataract cases. Posterior capsular opacification (PCO) was diagnosed in 30.9% of eyes without a significant difference in the IOL and aphakic groups (p=0.12). Aphakic glaucoma was diagnosed in 12/45 eyes at a median of 6.8 months (IQR 2.1–13.3 months) after surgery. Microcornea (5/12) and anterior segment anomalies (8/12) were associated with glaucoma development (p<0.05). Conclusion. Laterality and timing of surgery influence the outcome of pediatric cataract surgery. PCO was the most frequent postoperative complication. Aphakic glaucoma is often associated with ocular developmental abnormalities and a poor visual outcome

Searching for biological feedstock material: 3D printing of wood particles from house borer and drywood termite frass

Frass (fine powdery refuse or fragile perforated wood produced by the activity of boring insects) of larvae of the European house borer (EHB) and of drywood termites was tested as a natural and novel feedstock for 3D-printing of wood-based materials. Small particles produced by the drywood termite Incisitermes marginipennis and the EHB Hylotrupes bajulus during feeding in construction timber, were used. Frass is a powdery material of particularly consistent quality that is essentially biologically processed wood mixed with debris of wood and faeces. The filigree-like particles flow easily permitting the build-up of wood-based structures in a layer wise fashion using the Binder Jetting printing process. The quality of powders produced by different insect species was compared along with the processing steps and properties of the printed parts. Drywood termite frass with a Hausner Ratio HR = 1.1 with ρBulk = 0.67 g/cm3 and ρTap = 0.74 g/cm3 was perfectly suited to deposition of uniformly packed layers in 3D printing. We suggest that a variety of naturally available feedstocks could be used in environmentally responsible approaches to scientific material sciences/additive manufacturing