OPUS THD (Technischen Hochschule Deggendorf)
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Experimental investigation of ultrasonic vibration-assisted cryogenic minimum quantity lubrication for milling of Ti-6Al-4V and grinding of Zerodur
No full textIncreasing demands on component properties are leading to the development of high-performance materials for which conventional production methods are reaching their limits from an economic and ecological point of view. In recent years, two technologies have been developed that show great potential compared to conventional machining processes, particularly in machining high-performance materials such as the titanium alloy Ti-6Al-4V. Ultrasonic-assisted machining leads to reduced cutting forces and increased tool life. Cryogenic minimum quantity lubrication prevents the occurrence of high machining temperatures and allows higher material removal rates without a negative impact on tool life. This paper shows the influence of ultrasonic-assisted milling and grinding processes in combination with cryogenic minimum quantity lubrication on the machinability of the high-strength materials Ti-6Al-4V and Zerodur. The investigation addressed cutting forces, tool wear, and surface roughness. The superposition of the technologies resulted in longer tool life and lower tool wear for both milling and grinding. However, the surface roughness was consistently higher due to the ultrasonic superposition. Nevertheless, machining with ultrasonic vibration-assisted cryogenic minimum quantity lubrication has great potential for difficult-to-machine materials, especially due to the reduction in tool wear
Socio-Ecological Controversies from Chilean and Brazilian Sustainable Energy Transitions
No full textChile and Brazil have been historically recognised in South America for having a high share of renewable sources in their primary energy matrices. Furthermore, in the last two decades, aligned with the global efforts to conduct a sustainable energy transition, both countries have experienced a successful introduction of nonconventional renewable energy for power production. Nevertheless, some experiences with renewable sources have been demonstrated to be not entirely societally and environmentally friendly, as some local human communities and ecosystems are threatened, and conflicts have emerged, regardless of low-emission technology. Using the cases of Chile and Brazil, we aim to explore the socio-ecological dimension of sustainable energy transition—which has sometimes been ignored. We analyse the controversies regarding renewable energy and the emergence of socio-ecological conflicts through the principles of justice in transitions. Critical renewable conflicting power projects are identified using the Atlas of Environmental Justice’s database. Considering those experiences, we believe that reinforcing decision-making processes should be in synergy with identifying new alternatives to develop energy in both countries. Placing justice approaches at the centre of public policies is imperative to developing sustainable policies in the future
Towards fully automated inner ear analysis with deep-learning-based joint segmentation and landmark detection framework
No full textAutomated analysis of the inner ear anatomy in radiological data instead of time-consuming manual assessment is a worthwhile goal that could facilitate preoperative planning and clinical research. We propose a framework encompassing joint semantic segmentation of the inner ear and anatomical landmark detection of helicotrema, oval and round window. A fully automated pipeline with a single, dual-headed volumetric 3D U-Net was implemented, trained and evaluated using manually labeled in-house datasets from cadaveric specimen ( N=43) and clinical practice ( N=9). The model robustness was further evaluated on three independent open-source datasets ( N=23+7+17scans) consisting of cadaveric specimen scans. For the in-house datasets, Dice scores of 0.97 and 0.94, intersection-over-union scores of 0.94 and 0.89and average Hausdorff distances of 0.065and 0.14voxel units were achieved. The landmark localization task was performed automatically with an average localization error of 3.3 and 5.2voxel units. A robust, albeit reduced performance could be attained for the catalogue of three open-source datasets. Results of the ablation studies with 43 mono-parametric variations of the basal architecture and training protocol provided task-optimal parameters for both categories. Ablation studies against single-task variants of the basal architecture showed a clear performance benefit of coupling landmark localization with segmentation and a dataset-dependent performance impact on segmentation ability
Biomimetics for Sustainable Developments—A Literature Overview of Trends
No full textBiomimetics holds the promise to contribute to sustainability in several ways. However, it remains unclear how the two broad concepts and research fields are connected. This article presents a literature overview on biomimetic sustainable developments and research. It is shown that there is an increasing trend in publications dealing with various topics and that the research takes place worldwide. The biological models studied in biomimetic sustainable developments are mostly sub-elements of biological systems on a molecular level and lead to eco-friendly, resource and energy-efficient applications. This article indicates that biomimetics is further integrating sustainability to contribute to real problems in this context
Chronic kidney disease is related to impaired left ventricular strain as assessed by cardiac magnetic resonance imaging in patients with ischemic cardiomyopathy
No full textIntroduction
Chronic kidney disease (CKD) is an important cardiovascular risk factor. However, the relationship between CKD and myocardial strain as a parameter of myocardial function is still incompletely understood, particularly in patients with ischemic cardiomyopathy (ICM). Cardiac magnetic resonance imaging (CMR) feature tracking allows to analyze myocardial strain with high reproducibility. Therefore, the aim of the present study was to assess the relationship between CKD and myocardial strain as described by CMR in patients with ICM.
Methods
We retrospectively performed CMR-based myocardial strain analysis in 89 patients with ICM and different stages of CKD, classified according to the KDIGO stages. In all patients, global longitudinal strain (GLS), global circumferential strain (GCS) and global radial strain (GRS) analysis of left ventricular myocardium were performed. Furthermore, segmental longitudinal (SLS), circumferential (SCS) and radial strain (SRS) according to the AHA 16/17-segment model was determined.
Results
Creatinine levels (GLS: r = 0.46, p < 0.001; GCS: r = 0.34, p = 0.001; GRS: r = − 0.4, p < 0.001), urea levels (GLS: r = 0.34, p = 0.001; GCS: r = 0.30, p = 0.005; GRS: r = − 0.31, p = 0.003) as well as estimated glomerular filtration rate (GLS: r = -0.40, p < 0.001; GCS: r = − 0.27, p = 0.012; GRS r = 0.34, p < 0.001) were significantly associated with global strains as determined by CMR. To further investigate the relationship between CKD and myocardial dysfunction, segmental strain analysis was performed: SLS was progressively impaired with increasing severity of CKD (KDIGO-1: − 11.93 ± 0.34; KDIGO-5: − 7.99 ± 0.38; p < 0.001 for KDIGO-5 vs. KDIGO-1; similar data for SCS and SRS). Interestingly, myocardial strain was impaired with CKD in both segments with and without scarring. Furthermore, in a multivariable analysis, eGFR was independently associated with GLS following adjustment for LV-EF, scar burden, diabetes, hypertension, age, gender, LV mass or LV mass index.
Conclusion
CKD is related to impaired LV strain as assessed by CMR in patients with ICM. In our cohort, this relationship is independent of LV-EF, the extent of myocardial scarring, diabetes, hypertension, age, gender, LV mass or LV mass index
Comparison of Postoperative Serum Biomarkers after Total Hip Arthroplasty through Minimally Invasive versus Conventional Approaches: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
No full textBackground:
An effective way to objectively assess intraoperative tissue damage in total hip arthroplasty (THA) is to determine and compare postoperative serum biomarkers (laboratory parameters) such as creatine kinase (CK), C-reactive protein (CRP), and hemoglobin (Hb). This meta-analysis aims to compare the intraoperative tissue damage in THA through minimally invasive (MI) and conventional approaches (CAs) using postoperative serum biomarkers.
Methods:
We searched databases for randomized controlled trials (RCTs) comparing MI THA and CA THA. We calculated mean differences (MDs) with 95% confidence intervals (CIs) for continuous outcomes, using the Hartung–Knapp–Sidik–Jonkman method and a common effect/random effects model.
Results:
A total of 13 RCTs, involving 1186 THA patients, were included in our meta-analysis. In two out of eleven examined outcome parameters, MI THA showed better results than CA THA. In nine out of eleven examined outcome parameters, MI THA showed no significant difference compared to CA THA. MI THA had a 16 mg/L lower CRP value 3 days postoperatively than CA THA (I2 = 66%, p = 0.03, MD = −15.65, 95% CI −30.10 to −1.21). MI THA had a 3 mg/L lower CRP value 4 days postoperatively than CA THA (I2 = 0%, p = 0.98, MD = −3.00, 95% CI −3.27 to −2.74).
Conclusions:
Overall, there was no significant difference between MI THA and CA THA in terms of postoperative serum biomarkers, with a slight advantage of MI THA in CRP values. These results do not provide sufficient evidence to recommend changing the surgical approach from CA THA to MI THA.
Level of evidence I: a systematic review of all relevant randomized controlled trials
Health promotion networks in two districts in Bavaria, Germany: an exploratory case study mapping networks with respect to thematic agenda and location
No full textIntroduction
Building networks is an essential part of health promotion. However, network analysis remains relatively unexplored in this field. This study introduces a new technique that maps thematic agendas and geographical locations of health promotion actors.
Methods
This case study used elements of quantitative and qualitative methods to analyse network data. We used empirical data from two networks in Bavaria, a federal state of Germany.
Results
We identified a total of 55 actors in the first network and 64 actors in the second. We categorized the thematic agenda of actors according to their main field of work: “healthy childhood development,” “healthy middle age phase,” “healthy ageing,” “health equity in all phases of life.” One network showed a significant surplus of actors that focus on “healthy ageing.” We combined and analysed data from both networks collectively. Two districts with no health promotion actors within their geographical borders were identified. To put geographical gaps into context, data about deprivation and age was included.
Discussion
Results identified geographical areas with high need for support from health promotion actors. Through comparison of our results with existing literature, we derived potential network strategies for further successful networking. This study adds a new perspective to characterize health promotion networks by mapping them thematically and geographically. The concept can be used to give health promotion organisations relevant insight into network structures. This can improve decision-making processes concerning partnership strategy and finally lead to a positive health impact. Hence, our findings encourage further development of this technique and other networking methods in the field of health equity and health promotion
Risk Factors and Predictors for Functional Outcome and Complication Rate in Total Hip Arthroplasty through Minimally Invasive and Conventional Approaches: A Systematic Review and Meta-Regression Analysis of 41 Randomized Controlled Trials
No full textObjective:
To investigate and identify risk factors and predictors for the difference in functional outcome and complications between total hip arthroplasty (THA) through minimally invasive and conventional approaches, using a meta-regression analysis of randomized controlled trials (RCTs).
Methods:
A systematic review of the literature up to 31 July 2022 was performed. A meta-regression was conducted based on a random effects meta-analysis using the Hartung–Knapp–Sidik–Jonkman method. Results: A total of 41 RCTs with 3607 patients were found. The following predictors of HHS ≥ 6 months postoperatively were identified: patient age (predictor estimate = 0.14; p < 0.01), avascular necrosis of the femoral head (predictor estimate = −0.03; p = 0.04); incision length (predictor estimate = −0.82; p < 0.01). The following predictors of complication rate were identified: osteoarthritis (predictor estimate = 0.02; p = 0.02); femoral neck fracture (predictor estimate = −0.02; p = 0.02); SuperPATH (predictor estimate = −1.72; p < 0.01).
Conclusions:
Patient age, avascular necrosis of the femoral head, and incision length were identified as predictors of the effect size of the HHS ≥ 6 months postoperatively; and osteoarthritis, femoral neck fracture, and SuperPATH as predictors of the effect size of the complication rate. Based on these findings, we recommend that more frequent use of minimally invasive THA in elderly patients should be considered.
Level of evidence I: a systematic review of all relevant randomized controlled trials.
Registered in PROSPERO on 10 August 2022 (CRD42022350287)
Therapeutic Drug Monitoring in Children and Adolescents: Findings on Fluoxetine from the TDM-VIGIL Trial
No full textFluoxetine is the recommended first-line antidepressant in many therapeutic guidelines for children and adolescents. However, little is known about the relationships between drug dose and serum level as well as the therapeutic serum reference range in this age group. Within a large naturalistic observational prospective multicenter clinical trial (“TDM-VIGIL”), a transdiagnostic sample of children and adolescents (n = 138; mean age, 15; range, 7–18 years; 24.6% males) was treated with fluoxetine (10–40 mg/day). Analyses of both the last timepoint and all timepoints (n = 292 observations), utilizing (multiple) linear regressions, linear mixed-effect models, and cumulative link (mixed) models, were used to test the associations between dose, serum concentration, outcome, and potential predictors. The receiver operating curve and first to third interquartile methods, respectively, were used to examine concentration cutoff and reference values for responders. A strong positive relationship was found between dose and serum concentration of fluoxetine and its metabolite. Higher body weight was associated with lower serum concentrations, and female sex was associated with lower therapeutic response. The preliminary reference ranges for the active moiety (fluoxetine+norfluoxetine) were 208–328 ng/mL (transdiagnostically) and 201.5–306 ng/mL (depression). Most patients showed marked (45.6%) or minimal (43.5%) improvements and reported no adverse effects (64.9%). This study demonstrated a clear linear dose–serum level relationship for fluoxetine in youth, with the identified reference range being within that established for adults
Coronary microvascular dysfunction as assessed by angiography-derived index of microvascular resistance co-localizes with and may explain the presence of ischemia in stress-cardiac magnetic resonance imaging in the absence of coronary artery disease
No full textIntroduction
Ischemia with no obstructive coronary disease (INOCA) is a frequent phenomenon in the cath lab. A possible cause is coronary microvascular dysfunction (CMD), which may be assessed by invasive testing with possible complications; therefore, less invasive approaches have emerged, such as the angiography-derived index of microvascular resistance (aIMR). The aim of our study was to investigate the association of single-vessel aIMR as a measure of CMD with areas of INOCA in stress testing.
Methods
We measured aIMR in 286 vessels from 102 patients undergoing both stress cMRI and coronary angiography. Groups were (a) INOCA group (93 vessels, 32 patients); (b) coronary artery disease (CAD) control group (116 vessels, 42 patients) with ischemia due to relevant stenosis; and (c) control group (77 vessels, 28 patients) without ischemia or relevant stenosis.
Results
INOCA patients presented higher mean aIMR (28.3 ± 5.7) compared to both CAD patients (17.4 ± 5.7, p &lt; 0.001) and controls (22.1 ± 5.9, p &lt; 0.001). Furthermore, in INOCA patients aIMR was significantly increased (33.0 ± 8.1 vs. 25.8 ± 6.3, p = 0.021) in vessels with vs. without ischemia. Single vessel aIMR presented a very good diagnostic efficiency in detecting INOCA [AUC 0.865 (0.804–0.925), optimal cut-off 27.1, p &lt; 0.001].
Conclusion
CMD, as assessed by 3-vessel aIMR, co-localizes with and may explain the presence of ischemia in stress-cMRI in INOCA