Mapping internal strain fields of fused filament fabrication metal filled polylactic acid structure using digital volume correlation.

With the advancement in Fused Filament Fabrication (FFF), its application is increasing widely across different industries such as aeronautical, biomedical, robotics, etc. The internal structure is becoming more complex and intricate with varying materials of reinforcement which are used to improve mechanical properties. Current measurement techniques like Digital Image Correlation (DIC) are non-destructive testing methods that do not provide enough information on the behaviour of internal microstructure for anisotropic FFF materials. Digital Volume Correlation (DVC) is non-destructive testing technique which provides full field internal 3D deformation and strain fields. Copper particle filled PLA samples manufactured using FFF method with 20, 40, 60 and 80 infill percentages were loaded in tension inside Micro-CT. X-rays were passed through the sample to get a volumetric dataset for different loadings. Using DVC method on the dataset, internal displacement and strain fields were generated for 20, 40, 60 and 80 infill percentage FFF sample.

Digital volume correlation analysis of polylactic acid based fused filament fabrication printed composites.

Fused filament fabrication (FFF) has rapidly begun to see implementation in industrial fields as a method of rapid manufacturing. Traditional FFF parts are made from a single thermoplastic polymer. The polymer is heated to its melting point and deposited on a work bed where a model is gradually built from the base up. While traditional FFF parts have low mechanical properties, a reinforcing phase allows for improved mechanical properties. The addition of a reinforcing material to the base polymer and complex internal microstructure of the 3 D printed party leads to anisotropic mechanical properties. Thus, these materials' mechanical properties become challenging to characterize using traditional measurement techniques due to the previously mentioned factors. Therefore, it is essential to develop a method in which mechanical properties can be measured and analyzed. This study aims to characterize the mechanical behaviour under a uniaxial tensile load of an FFF produced polylactic acid (PLA)-copper particulate composite. The internal response of the FFF sample was imaged using micro-computed tomography at predetermined loads. The µ-CT images were input into an open-source digital volume correlation (DVC) software to measure the internal displacements and strain tensor fields. The study results show the development of different strain fields and interior features of the FFF parts.

Interpreting the dynamic equilibrium during evaporation in a cesium environment.

The cesium ovens for the prototype source of the ITER neutral beam injectors are currently tested in the CAesium Test Stand (CATS) facility, with a background pressure of 10-6 mbar. Different diagnostics are here installed: two Langmuir-Taylor detectors allow us to determine the Cs vapour evaporation rate from the oven and the Cs density at different positions in the vacuum chamber; and laser absorption spectroscopy is used to measure the density integrated over a line of sight and a quartz crystal microbalance to detect the cesium mass deposited in time over a surface. In this paper, we present a model to describe the dynamic equilibrium in the evaporation chamber of CATS with the first oven tested in order to gain information about the Cs sticking coefficient at the walls. The model hence includes sticking and energy accommodation of the Cs atoms to the walls, calculates the flux density at the surfaces, and provides the Cs atom density at any location in the volume. By this model, we simulate the Cs evaporation and the equilibrium density, comparing the modeled results with the experimental data. As a result, a sticking coefficient of 2% is obtained.

Fluoroscopy-guided gastric peroral endoscopic pyloromyotomy (G-POEM): a more reliable and efficient method for treatment of refractory gastroparesis.

INTRODUCTION: Prior studies show promising results of the gastric peroral endoscopic pyloromyotomy (G-POEM) procedure for treatment of refractory gastroparesis. One major technical challenge involved in this procedure is identifying the pyloric muscular ring (PMR). The aim of this study is to establish a reliable method for identification of the PMR during G-POEM. METHODS: Fluoroscopy-guided G-POEM was performed by placing an endoclip at the 9 to 11'o clock position at the pylorus for identification of PMR. Conventional G-POEM was performed by observation of blue colored mucosa at the pylorus area as an indirect marker for PMR. The degree of the PMR identification was graded into well identified, identified, and not identified based on the appearance of the PMR. Procedure times were accurately documented. Gastroparesis cardinal symptoms index and gastric emptying scintigraphy were evaluated before and after the procedure. RESULTS: Fourteen patients were studied, seven underwent fluoroscopy-guided G-POEM, and seven patients underwent conventional G-POEM. All procedures achieved technical success and no adverse events occurred. In the seven patients who underwent fluoroscopy-guided G-POEM, the PMR was well identified in four patients and identified in three patients. In the seven patients who underwent conventional G-POEM, the PMR was identified in four patients and not identified in three patients. The average time to complete the fluoroscopy-guided G-POEM was significantly shorter than that of the conventional G-POEM. CONCLUSIONS: Fluoroscopy-guided G-POEM by placement of an endoclip at the pylorus was a reliable and safe method to direct the orientation of the submucosal tunnel, to facilitate the location of the PMR, and to shorten the procedure time.

Cytokinesis-block micronucleus assay by manual and automated scoring: calibration curves and dose prediction.

The cytokinesis-block micronucleus assay in peripheral blood lymphocytes is one of the best standardized and validated techniques for individual radiation dose assessment. This method has been proposed as an alternative to the dicentric chromosome assay, which is considered the "gold standard" in biological dosimetry because it requires less time and cytogenetic expertise. Nevertheless, for application as a biodosimetry tool in large-scale nuclear or radiological accidents, the manually performed cytokinesis-block micronucleus assay needs further strategies (e.g., the automation of micronucleus scoring) to speed up the analysis. An essential prerequisite for radiation dose assessment is to establish a dose-effect curve. In this study, blood samples of one healthy subject were irradiated with seven increasing doses of x-ray (240 kVp, 1 Gy min⁻¹) ranging from 0.25-4.0 Gy to generate calibration curves based on manual as well as on automated scoring mode. The quality of the calibration curves was evaluated by determination of the dose prediction accuracy after the analysis of 10 blood samples from the same donor exposed to unknown radiation doses. The micronucleus frequencies in binucleated cells were scored manually as well as automatically and were used to assess the absorbed radiation doses with reference to the respective calibration curve. The accuracy of the dose assessment based on manual and automatic scoring mode was compared.

Chronic migraine in women is associated with insulin resistance: a cross-sectional study.

BACKGROUND AND PURPOSE: Migraine is a common neurological disorder. It can be divided into episodic migraine (EM) and chronic migraine (CM), based on headache frequency. Some studies have shown that insulin sensitivity is impaired in migraine; moreover, hypertension, diabetes and obesity are common in patients with CM. The aim of this study was to assess serum glucose, insulin levels and insulin resistance (IR) in a sample of episodic migraineurs, chronic migraineurs and non-pain healthy controls. METHODS: Eighty-three women with EM, 83 with CM and 83 healthy controls were recruited. Headache was diagnosed according to the latest International Classification of Headache Disorders 2 criteria. Waist circumference, body mass index (BMI) and blood pressure were measured. Checked metabolic parameters included fasting glucose, the 2 h 75 g oral glucose tolerance test (2 h OGTT), serum HbA1c, blood lipid profile, C-reactive protein and prolactin. The homeostasis model assessment formula was used to calculate IR. RESULTS: A significant prevalence of IR in CM was observed (P = 0.002). No significant associations were found with fasting glycaemia, the 2 h OGTT, HbA1c, blood lipid profile, C-reactive protein, prolactin and waist circumference. Obesity (BMI >30 kg/m(2)) was associated with an increased risk of CM [odds ratio (OR) 2.4]. When the outcome of interest was the association between IR and obesity, the OR was significantly increased compared with IR alone (OR = 13.2). CONCLUSION: This may suggest that CM is associated with IR status, particularly when it is in partnership with obesity.

Use of recombinant interferon alfa-2b in the treatment of basal cell carcinoma.

BACKGROUND: Several neoplasms including cutaneous T-cell lymphomas, malignant melanoma and Kaposi's sarcoma have been successfully treated with systemic or intralesional interferons (IFNs). Recently, intralesional alpha-IFN has also been employed in the treatment of basal cell carcinoma (BCC). OBJECTIVE: The aim of our study was to evaluate the efficacy of IFN alfa-2b in the treatment of BCC. METHODS: 140 patients with BCC were treated with intra- und perilesional injections of recombinant IFN alfa-2b at a dosage of 1.5-3 x 10(6) IU, three times a week for 4-8 weeks. RESULTS: Complete response was achieved in 94 patients (67.1%), partial response in 33 patients (23.6%) and no response in 13 patients (9.3%). Side effects included fever, headache, fatigue and nausea but were reversible with the use of paracetamol. None of the patients discontinued therapy due to side effects. After a mean follow-up period of 36 months (12-54 months) no relapse has been observed. CONCLUSION: Based on our results, intra- and perilesional IFN alfa-2b represents an effective, alternative treatment for BCC.