bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding Impacts of Groundwater Extraction on Flow Dynamics in Multi-aquifers in the Ho Chi Minh City Area, Vietnam
Authors:   Ho Chi Minh City University of Technology, and Vietnam National University, Ha Quang-Khai , Koontanakulvong Sucharit ,   Chulalongkorn University
Published: December 2024

Understanding the dynamic characteristics of the groundwater flow budget is crucial for effective water management. This study investigates the groundwater budget in the Ho Chi Minh City (HCMC) area by the application of groundwater flow modeling. A 3D model was built to simulate groundwater flow in aquifer systems in Ho Chi Minh City, using extensive hydrogeological data from 400 borehole logs, along with climate, hydrological, and groundwater extraction data. The model was calibrated in both steady-state and transient conditions, with monthly data from 1995–2007, and then validated using five years of monthly groundwater level monitoring data from 2008–2012. In general, the calibrated and validated models show a good match between calculated and observed groundwater levels, with R2 values > 0.8. The model results illustrate that recharge rates in HCMC vary according to local geological conditions and fluctuate seasonally due to changes in climate factors such as rainfall and evaporation. The annual recharge rate did not significantly change during 1995–2012. A groundwater depression cone was observed in the city center, with a maximum groundwater level approximately 50 meters below mean sea level (bmsl). Groundwater extraction increased sixfold from 1995–2012, which is the main cause of groundwater level decline. This study also found that the river system plays an important role in maintaining the groundwater balance in the area. As a result, increased groundwater exploitation has induced a fourfold rise in river leakage, while groundwater discharge to the river decreased by 35% during the same period. These changes potentially contribute to increased risks to groundwater quality, a reduction in base flow within the river system, and greater vulnerability of the natural ecosystem.
Concept of a load reducing knee-orthosis
Authors: Abdulrazeq Abdallah , Al-Hazba Ahmed , Pöschel Till , Thomas Hanna , Boese Axel
Published: December 2024

Joint diseases are one of the significant challenges that come with age. The pain that these diseases cause can affect the quality of life of the patient, especially if the disease is causing aches in a high-load-bearing joint like the knee. Most patients these days choose to undergo total joint arthroplasty. However, some patients cannot do the surgery for different reasons or choose to delay it as late as possible. Their only option is to use a walking stick with the associated restrictions in terms of quality of life and incorrect physical strain. To help those patients and reduce their pain, this work aimed to create a concept that reduces the load acting on the knee and lower leg. Alleviating the load on the knee joint has been identified as a crucial factor in reducing pain associated with various knee conditions. To achieve this, the load should be partially transferred from the upper leg to the ground. Following the primary design process stages, a first demonstrator was built and tested. The results of the tests indicated that the device could reduce 30 % of the load exerted on the knee during the first phase of walking. Moreover, it takes around 27 seconds to fasten the device to the user's leg. The overall conclusion is that the first demonstrator proved the validity of the main concept, although there is room for improvement.
Multi-view surgical phase recognition during laparoscopic cholecystectomy
Authors: Bajraktari Flakë , Pott Peter P.
Published: December 2024

In the realm of laparoscopic procedures, intelligent context-aware assistance systems hold promise for enhancing surgical workflows and patient safety. This study employs a multi-view approach to recognize surgical phases, combining data from a laparoscopic camera and an in-room camera simultaneously. The study aimed to improve phase recognition accuracy using a Transformer-based model with late sensor fusion, which yielded mixed results. The data poses significant challenges, as self-recorded videos are insufficient for extracting relevant information, necessitating real-world data. Additionally, the overall model needs refinement, as certain components degrade performance with poor data. This research highlights the complexities and opportunities in integrating multiview data for surgical phase recognition, emphasizing the importance of diverse data collection strategies and model architectures for real-world surgical settings.
Enhancing No Reference Laparoscopic Video Quality Assessment with Evolutionary ANFIS
Authors: Biswas Sria , Palanisamy Rohini
Published: December 2024

Distortions in laparoscopic videos affect surgeon visibility and surgical precision, underscoring the need for sustained high video quality. This study presents a real-time laparoscopic video quality assessment algorithm independent of reference content availability. Statistical parameters derived from luminance, local binary pattern and motion-vector maps of video frames are observed to effectively discern distortion types and severities. These parameters are used to train an evolutionary adaptive neuro-fuzzy inference system (ANFIS) end-to-end with subjective score labels. Training and validation loss curves saturate at the 85th epoch, demonstrating the model’s efficient data fitting capability. Performance comparison with other state-of-the-art methods reveals superior results, with high correlation scores of 0.9989 and 0.9446 for experts and 0.9956 and 0.9847 for non-experts, alongside low root mean square errors of 0.0828 and 0.1685 for expert and non-experts, respectively. The model accurately replicates the expert and non-expert perceptual opinions, encouraging future research in stereoscopic, augmented, and virtual reality data.
Using a confined space to boost the driving amplitude of pulsating bubbles to facilitate jetting
Authors: Carlson Craig S. , Anderton Nicole , Aharonson Vered , Otake Naoyuki , Xinyue Hu , Yamasaku Momoka , Hashimoto Mamoru , Kudo Nobuki , Postema Michiel
Published: December 2024

A bubble collapsing near an interface may result in the formation of a liquid jet protruding from the distal bubble side, through the bubble, towards the interface. Ultrasound assisted jetting has been observed when subjecting, by approximation, infinite fluids to acoustic amplitudes above the inertial cavitation threshold, limiting the possibility of ultrasoundguided, bubble-assisted drug or gene delivery. However, the vascular system can be regarded as a finite fluid. The purpose of this study was to investigate the feasibility of lowamplitude jetting for fluid containing biocompatible cavitation nuclei, by placing the region of interest in a confined space to ensure a standing wave field. Droplets of QuantisonTMultrasound contrast agent were pipetted into a Perspex cylindrical compartment of 8-mm diameter and 2-mm height, which was part of an imaging system. The contrast agent was subjected to 3-cycle ultrasound pulses with a centre frequency of 1MHz whilst being observed at a frame rate of ten million frames per second. Jetting was observed to occur with microbubbles nucleated from the contrast agent in an acoustic regime whose free-field mechanical index was 0.6. Empirical curve matching showed a pulse amplification by a factor of six owing to the chosen geometry. Visible jet lengths of twice the bubble radius on the verge of collapse were measured. Owing to the confined space, the local acoustic amplitude was amplified to surpass the cavitation threshold. This finding is of interest for medical ultrasonic applications where the local environment comprises reflectors.
Non-invasive and continuous monitoring of 3D stem cell culture in a bioreactor
Authors: Carrillo Mario , Altmaier Saskia , Meiser Ina , Ihmig Frank R.
Published: December 2024

The development and discovery of new drugs and therapy products in regenerative medicine are carried out through multiple stages which involve several strict quality protocols. The use of cell-based model systems is the most relevant alternative to deviate from animal testing. However, the underlying biomanufacturing process in a 3D environment can be prone to failures or unexpected behaviors such as cell growth anomalies or inconsistencies in cell aggregation, which can seriously affect the quality of the result. Therefore, it is necessary to establish a non-invasive and continuous monitoring mechanism that minimizes contamination risks, allows taking early decisions and enables large-scale production in the long term. The results of our embedded machine learning approach show that it is feasible to train machine learning models that can operate on a resourcelimited embedded board with acceptable prediction accuracy for the estimation of the average size of growing stem cell spheroids. Further experiments are needed to investigate the full information potential of the recorded process data.
Development and Validation of a Patient Model for Simulating Anaesthetic Uptake
Authors: Demgensky Clara , Hennigs Carlotta , Kater Andreas , Bargstädt Björn , Rostalski Philipp
Published: December 2024

Mathematical patient models play a profound role in the managing and understanding of anaesthesia. This article proposes a patient model for simulating anaesthetic uptake, i.e. the storing of anaesthetic gases in the human body, thus extending a well known four compartment model from literature. Real time data is used for the simulation, from which the sevoflurane concentration is extracted. The exhaled concentrations from the model and the data are compared. A literature model is extended with ratios of compartmental perfusion, the introduction of coefficients representing diffusion and the change of the solubility coefficient. The extended and the literature model are applied to five training data sets, with prior optimization of the parameters that have the most impact. Afterwards, both models are validated on five additional data sets. The results of the extended model are mostly better than the results of the literature model. Therefore, the extensions improve the model for the used data, but need to be validated with a larger amount of data.
Impact of the European proposal to restrict PFAS on modern medical technology and treatment options
Authors: Derad Lukas , Thaler Melanie , Wiktor Kevin , Bregulla Rainer , Bader Christian
Published: December 2024

Functionality of state-of-the-art medical devices often depends on high-end materials. Today, a large spectrum of medical devices like heart valves, vascular grafts, sutures or endoscopic devices consist of or incorporate fluoropolymers like polytetrafluoroethylene (PTFE). Fluoropolymers offer unique mechanical, electrical and chemical properties. Based on their chemical constitution, fluoropolymers are assigned to the group of per- and polyfluorinated substances (PFAS). The aim of the current restriction proposal within Europe (EU) is to limit and/or fully ban the persistent PFAS substances known as forever chemicals. The restriction proposal concerns all PFAS substances beyond further subdividing and evaluating their hazardous potential and with just short-term derogations depending on the application. The consequences of the impending restriction proposal on PFAS is shown from a medical device industry viewpoint. Literature data on annual material consumption and supply chain are collected and evaluated, especially pointing to future problems assuming an entry into force of the pending restriction proposal. Furthermore, the short derogation times are contextualized with current timelines of Medical Device Regulation (MDR) approval processes to highlight the impact on product availability assuming a PFAS ban. Selected examples of affected products illustrate, how patient treatment options are limited by the PFAS restriction. It can be clearly shown that the PFAS restriction will critically affect the medical device sector through collapsed supply chain and insufficient derogation times for product approvals, thus limiting the availability of medical products and setting back the gold standards in medical treatment.
Integration Models for SDC-capable Medical Devices into an Existing OR Network
Authors: Deutschle Jennifer , Beyersdorffer Patrick , Junger Denise , Tangemann Michael , Seitz Björn , Burgert Oliver
Published: December 2024

The interconnection of medical devices in an operating room (OR) represents a major step in optimizing clinical processes and increasing the quality of treatment. The IEEE 11073 Service-oriented Device Connectivity (SDC) standard family constitutes the foundation for manufacturerindependent information exchange and remote control of medical devices. However, integrating new SDC-capable devices into an existing OR network poses a major challenge for medical device manufacturers. Thus, suitable integration models are required. This work focuses on the definition of three possible integration models and their comparison according to architectural design patterns. Thereby, the use case of integrating a high-frequency (HF) surgical device to interconnect with existing SDC-capable devices is pursued. One of the models, which focuses on high expandability and low coupling, was successfully applied to interconnect an HF surgical device with an OR light in the research OR of Reutlingen University. The results indicate transferability to other integration scenarios and are intended to further promote manufacturer-independent integrated ORs.
Pressure Modulation Improves Locomotion of an Expanding Robot for Colonoscopy
Authors: Dinkel Johanna , Weinmann Denise , Pott Peter P. , Schäfer Max B.
Published: December 2024

Colonoscopy plays a pivotal role in early colorectal disease detection. It is hindered by procedural difficulties such as friction between colonoscope and colon wall as well as maneuverability issues. Expanding robots offer a promising alternative, aiming for a reduced risk of tissue damage and reduced forces between colononscope and tissue. In this paper, the usage of expanding locomotion for colonoscopy is investigated to address technical challenges. Preliminary tests on a custom-designed test rig demonstrate the potential of intermitted advancement and retraction modes to overcome challenges such as the difference in pathlength of robot body and working channel as well as the typical buckling during retraction of expanding robots. Future research will focus on refining control systems based on sensor feedback and evaluating additional parameters for clinical application.
Comparison of YOLO and transformer based tumor detection in cystoscopy
Authors: Eixelberger Thomas , Maisch Philipp , Belle Sebastian , Kriegmaier Maximilian , Bolenz Christian , Wittenberg Thomas
Published: December 2024

Background: Bladder cancer (BCa) is the second most common type of cancer in the genitourinary system and causes approximately 165,000 deaths each year. The diagnosis of BCa is primarily done through cystoscopy, which involves visually examining the bladder using an endoscope. Currently, white light cystoscopy is considered the most reliable method for diagnosis. However, it can be challenging to detect and diagnose flat, small, or poorly textured lesions. The study explores the performance of deep learning systems (YOLOv7- tiny, RT-DETR18), originally designed for detecting adenomas in colonoscopy images, when retrained and tested with cystoscopy images. The deep neural network used in the study was pre-trained on 35,699 colonoscopy images (some from Mannheim) and both architectures achieved a F1 score of 0.91 on publicly available colonoscopy datasets. Results: When the adenoma-detection network was tested with cystoscopy images from two sources (Ulm and Erlangen), F1 scores ranging from 0.58 to 0.81 were achieved. Subsequently, the networks were retrained using 12,066 cystoscopy images from Mannheim, resulting in improved F1 scores ranging from 0.77 to 0.85. Conclusion: It could be shown that transformer based networks perform slightly better than YOLOv7-tiny networks, but both network types are feasable for lesion detection in the human bladder. The retraining of the network with additional cystoscopy data led to an improvement in the performance of urinary lesion detection. This suggests that it is possible to achieve a domain-shift with the inclusion of appropriate additional data.
Bioresorbable Vascular Scaffolds for the Treatment of Aortic Coarctation in Pediatric Patients – Aspects of Dimensional and Mechanical Performance
Authors: Fiedler Nicklas , Oschatz Stefan , Ince Hüseyin , Grabow Niels , Lebahn Kerstin
Published: December 2024

At present, there are no bioresorbable systems available for the treatment of aortic coarctation in pediatric patients. However, experience with off-label used systems and knowledge of bioresorbable scaffolds in other applications suggest potential benefits. While stenting techniques are typically preferred for older children, there have been encouraging reports regarding their use in newborns and very young infants recently. Bioresorbable scaffolds could potentially close the technological gap in this area and serve as a bridge therapy for non-operable patients. This work identifies geometric and loading aspects in the light of current literature to improve the growth-responsive development of new scaffolds for the treatment of congenital heart diseases with pediatric-specific characteristics.
Rethinking AI with Transformative Philosophy
Authors: Bruno Gransche
Published: December 2024

This paper introduces the Transformative Philosophy (T:Phil) program, an initiative designed to embed ethical and socio-political literacy into the technological development process. T:Phil, developed within the Digitalized Lifeworld research cluster and in partnership with leading international technology reflection experts, provides a comprehensive framework for integrating philosophical insights with technical expertise. Aimed at decision-makers in the tech industry, T:Phil delivers tailored content through modular series such as Re:Thinking Technology, which challenge participants to reconsider their approaches to AI, digital infrastructures, and our language of technology. The paper highlights two key modules of the T:Phil program: The first, AI in an Atlas-View, promotes a holistic understanding of AI by examining its technical, human, and environmental aspects. This module encourages participants to view AI as a complex socio-technical ensemble rather than merely a technical innovation. The second module, AI as a Metaphor, explores the metaphorical language used to describe AI, fostering critical awareness of how these metaphors shape our perceptions and influence the ethical considerations of AI deployment. Through innovative delivery methods, including hybrid keynote- discussion events, short series, and intensive Thinkathons, T:Phil engages technical professionals in reflective practices that enhance their understanding of technology’s - especially AI’s - broader implications. The program aims to help cultivate a new cadre of ethically and philosophically informed tech experts capable of designing AI systems that promote equitable and just outcomes. This paper briefly introduces the T:Phil program and provides examples of its application, demonstrating its potential to transform the way we integrate ethical reflection into technology development.
Ultrasound-based Eigenfrequency Analysis to Determine Material Parameters of Tissue Mimicking Phantoms
Authors: Heim Christian , Huber Christian M. , Ullmann Ingrid , Lyer Stefan , Rupitsch Stefan J.
Published: December 2024

A modern area of research in cancer treatment is magnetic drug targeting (MDT) with superparamagnetic iron oxide nanoparticles (SPIONs). In order to understand the processes involved in MDT in more detail and to be able to perform this therapy as efficiently as possible, a monitoring system for the spatial distribution of SPIONs in biological tissue is required. One approach is to use magnetomotive ultrasound (MMUS) to monitor the spatial distribution over time. However, the spatial distribution of SPIONs cannot be quantitatively determined applying basic MMUS algorithms. Therefore, MMUS has been extended by a simulation part to quantitatively determine the spatial distribution of SPIONs. This extended MMUS algorithm requires the material parameters and the geometry of the target tumorous tissue. In this contribution, we describe an ultrasound-based eigenfrequency analysis combined with an iterative inverse simulation-based method to determine the mechanical parameter Young's modulus of tissue mimicking phantoms. The presented approach yields a good estimate of the Young's modulus compared to the result from a compression test.
Investigation on surface properties of lasertextured Ti-6Al-4V ELI biomaterial
Authors: Hiremath Somashekhar S. , Gupta Arnab , Amin Ankit T. , Ramakrishnan S.
Published: December 2024

In this paper, a thorough analysis of nanosecond laser texturing on Ti-6A1-4V ELI material was carried out, with a particular emphasis on the modulation of laser process parameters and their effects on surface morphology, elemental composition, microscale topographical features, and wettability. The laser-textured samples exhibit unique surface morphologies that were identified by different topographical metrics such as average surface roughness (Sa), surface development ratio (Sdr), peak-to-peak distance (dp), and peak-to-valley height (hp) along parallel and perpendicular to laser scanning directions. The energy dispersive x-ray spectroscopy (EDS) was used to examine the differences in elemental composition and crystallographic constitution of the samples revealed using the x-ray diffraction analysis (XRD). Further contact angle measurement in both the parallel and perpendicular directions revealed the hydrophobicity of the laser-textured surfaces. Out of 4 samples, LT-2 and LT-4 samples displayed noticeably larger contact angles, demonstrating a high degree of hydrophobicity in both directions. Improved hydrophobicity of the textured surfaces may lead to reduced bacterial attachment, whereas anisotropic surface features at the microscale may provide contact guidance to osteoblast cells, opening up avenues for regenerative tissue engineering on biomaterial interfaces.
Magnetomotive Displacement of Magnetic Nanoparticles in Different Tissue Phantoms
Authors: Huber Christian Marinus , Heim Christian , Li Jiaqi , Ermert Helmut , Rupitsch Stefan J. , Ullmann Ingrid , Lyer Stefan
Published: December 2024

Magnetic nanoparticles (MNPs) can be used in various biomedical applications, such as magnetic drug targeting (MDT) or magnetic hyperthermia for cancer treatment. MNPs are injected into the body and accumulated with an external magnetic field at the tumor site. For therapy monitoring, the MNPs distribution has to be accurately mapped in real time. Magnetomotive ultrasound (MMUS) is a suitable technique for this purpose. It was already demonstrated that MMUS can map the accumulation process of MNPs during MDT. Moreover, inverse MMUS is an advanced technique to quantify MNP distribution. This method simulates the displacement of MNPs and surrounding tissues and compares the results to measured data. Understanding how magnetomotive displacement behaves in various elastic environments is crucial for advancing inverse MMUS and accurately quantifying MNP distributions. In this study, ultrasound tissue phantoms were fabricated with varying elastic parameters, incorporating MNPs. Subsequently, their MMUS displacement is assessed.
Ultrasound-Induced Stable and Inertial Cavitation of Magnetic Nanoparticles for Drug Delivery Applications
Authors: Huber Christian Marinus , Hageroth Lars , Meyer Constanze , Ermert Helmut , Ullmann Ingrid , Vossiek Martin , Lyer Stefan
Published: December 2024

Drug-loaded magnetic nanoparticles (MNPs) accumulated by an external magnetic field already showed their efficacy in localized tumor treatment in animal studies. Furthermore, specific MNPs are sonosensitive, enabling them to generate inertial cavitation when exposed to a focused ultrasound field. This can be used for controlling drug release, as well as for particle detection and mapping. In addition to inertial cavitation, stable cavitation is also a part of the cavitation process, which has not yet been evaluated on MNPs. While stable cavitation is less harmful to surrounding tissue compared to inertial cavitation, it also contributes to enhanced tumor perfusion. Hence, an optimal strategy could involve inducing inertial cavitation only within the tumor region for drug release and mapping, while employing stable cavitation outside the tumor to enhance perfusion. This study aims to investigate stable cavitation mediated by MNPs for the first time, while examining their overall cavitation behavior.
De novo establishment of an ex vivo culture for living myocardial slices applying a microphysiological system – MPSlms
Authors: Jordan Maria , Schmieder Florian , Waleczek Florian J. G. , Polk Christoph , Stucki-Koch Angelika , Philipp Jürgen , Dietzel Leila , Clement Alexander , Behrens Stephan , Thum Thomas , Sonntag Frank , Fiedler Jan
Published: December 2024

Cardiovascular disease is a global health burden. To develop novel treatment options complex in vitro model systems are needed that resemble the pathophysiological situation ex vivo. Nevertheless, current pre-clinical in vitro models for pharmacological research are limited in complexity. Basic cell culture models lack cardiac tissue architecture and intercellular communication, limiting their translational capability. Force measurement methods on ex vivo cultured living myocardial slices (LMS) have been described for contraction analysis studies after compound treatment. Here, we combined LMS with a microphysiological system (MPS) to develop MPSlms as heart-on-chip approach that enables advanced nutrition circulation and integrates electrical pacing (MPSpacer) of the ex vivo cardiac tissue. To optimize the LMS technique, we designed a novel isometric tissue holder (ITH) and miniaturized the LMS format, allowing for extended condition testing and thus refinement of animal experiments. The contractile performance of cardiomyocytes was quantified by applying optical mapping of movement detection, which revealed precise and local variations in contraction within one LMS.
Vector Network Analyzer (VNA) Measurements for Electrical Impedance Tomography
Authors: Karime Ahmad , Battistel Alberto , Möller Knut
Published: December 2024

Electrical Impedance Tomography is a noninvasive imaging technique that employs electrical currents to reveal the internal conductivity distribution within the body. The study follows a new Radio Frequency (RF) approach, by using a Vector Network Analyzer to provide a multifrequency measurement between 10 kHz and 1 GHz. A plastic and a metallic object were positioned within a saline-filled phantom to test the EIT reconstructed images at different frequencies. The results show that based on the image reconstruction, the material’s conductivity can be distinguished at specific frequencies. However, beyond 10 MHz, the reconstructed images become less reliable until reaching 1 GHz, where the reconstructed image deteriorates significantly. While Electrical Impedance Tomography (EIT) has potential in new applications, its efficacy is limited by the ill-posed problem of the reconstruction. Further development and refinement of techniques, particularly in addressing issues that occur at higher frequencies, are required to realize EIT’s full potential in various fields.
Can Auditory Stimulation Improve Sleep Apnea?
Authors: Kranz Dominik D. , Salanitro Matthew , Osmers Eike , Rosenblum Lisa , Schöbel Christoph , Kolossa Dorothea , Penzel Thomas , Wessel Niels
Published: December 2024

Recent advancements in the field of acoustic stimulation have shown promising effects on the autonomic nervous system, influencing parameters such as heart rate [1] and cognitive performance [2]. In this study, we analyzed polygraphy data from patients with heart failure related central sleep apnea. We compared the Apnea-Hypopnea Index (AHI) during a baseline night with that during a night where acoustic stimulation was applied for 40 minutes before bedtime. Seven out of eight patients showed a significant reduction in AHI during the intervention night (p < 0.01). These preliminary findings suggest that further investigation in a more controlled environment is warranted.
Numerical Analysis of Geometric Influences in Tetrapolar Electrical Impedance Spectroscopy Using Monte Carlo Simulations
Authors: Lovasz Zoltan , Atmaca Ömer , Veil Carina , Herkommer Alois , Sawodny Oliver
Published: December 2024

Electrical impedance spectroscopy is promising for intraoperative cancer diagnosis by differentiating tissue based on its electrical properties, yet faces challenges from material nonlinearities and sensor effects. In this study, 3D finite element simulations were performed to analyze geometric dependencies. Two different tetrapolar ring electrode layouts are placed on virtual piece of normal and tumor tissue with each radius varied using Monte Carlo simulations and the resulting impedances and cell constants were evaluated statistically. Additionally, a novel sensitivity quality metric is introduced, enabling the identification of the geometry more suitable for impedance measurements. The results highlight the superior sensitivity quality of the improved geometry. Future research should integrate the geometric Monte Carlo approach with variations of dielectric properties of tissue and optimizing the quality metric taking electrode polarization effects into considerations.
Temperature dependence of shape recovery of HMW and VHMW poly-(L-lactide)
Authors: Oschatz Stefan , Schultz Selina , Fiedler Nicklas , Grabow Niels
Published: December 2024

Within this work, the influence of recovery temperature on thermal induced shape recovery behaviour of injection molded biodegradable poly-(L-lactide) (PLLA) was investigated. Shape retention, shape recovery and shape recovery rate were determined for high molecular weight (HMW) PLLA (320 kDa) and very high molecular weight (VHMW) PLLA (700 kDa) at recovery temperatures of 50, 60, 70, 80 and 90 °C, respectively, using DMA experiments. It was found that for both polymers, shape recovery reached a plateau of around ~70% at 80 °C, which could not be increased at higher temperatures. However, shape recovery rate did show to be affected by higher temperatures. Moreover, it was found that the polymer with the higher molecular mass exhibited a higher shape recovery rate.
Precise processing of pure undiluted PEGDA via inkjet printing for drug release systems
Authors: Sannan Ahmed , Eickner Thomas , Teske Michael , Mau Robert , Grabow Niels , Seitz Hermann
Published: December 2024

Poly(ethylene glycol) diacrylate (PEGDA) is a common polymer in the field of biomedical engineering and can be used for the production of drug delivery systems (DDS). The main advantages of PEGDA are biocompatibility and the ability to alter the physical and chemical properties, thereby ensuring individualized drug release behaviour. The processing of PEGDA via inkjet printing is relevant for the production of DDS. This can be challenging due to the high viscosity of pure PEGDA. In this work, PEGDA, with a molecular weight of 250 g/mol (PEGDA250), was inkjet printed using a Nanoplotter 2.1 with a piezoelectric heatable NanoTip HV-J-H printhead (GeSiM mbH, Radeberg, Germany) at different voltages and temperatures. Droplet generation was analysed in terms of droplet volume and angle deviations. PEGDA250 can be inkjet printed reproducibly in a voltage range of 60 V - 80 V at room temperature (20 °C) or heated up to 38 °C. The average volume of heated (38 °C) PEGDA250 droplets was approximately 110 pl - 150 pl higher than the droplet volume of PEGDA250 in the unheated state. The average angle deviations of main and satellite droplets were mostly < 3°. Increasing voltage or excessive heating of more than 38 °C caused greater instabilities in the droplet generation as well as larger satellite droplets which can affect the accuracy negatively. The studies have shown that PEGDA250 can be processed via inkjet printing and thus can be used as a drug carrier for DDS without the need for mixing with a solvent.
Influencing Factors on the Registration Accuracy of a Learned Feature Descriptor in Laparoscopic Liver Surgery
Authors: Schwab Sara , Krames Lorena , Nahm Werner
Published: December 2024

In laparoscopic liver surgery, image-guided navigation systems provide crucial support to surgeons by supplying information about tumor and vessel positions. For this purpose, these information from a preoperative CT or MRI scan is overlaid onto the laparoscopic video. One option is performing a registration of preoperative 3D data and 3D reconstructed laparoscopic data. A robust registration is challenging due to factors like limited field of view, liver deformations, and 3D reconstruction errors. Since in reality various influencing factors always intertwine, it is crucial to analyze their combined effects. This paper assesses registration accuracy under various synthetically simulated influences: patch size, spatial displacement, Gaussian deformations, holes, and downsampling. The objective is to provide insights into the required quality of the intraoperative 3D surface patches. LiverMatch serves as the feature descriptor, and registration employs the RANSAC algorithm. The results of this paper show that ensuring a large field of view of at least 15-20% of the liver surface is necessary, allowing tolerance for less accurate depth estimation.
HOLa: HoloLens Object Labeling
Authors: Schwimmbeck Michael , Khajarian Serouj , Holzapfel Konstantin , Schmidt Johannes , Remmele Stefanie
Published: December 2024

In the context of medical Augmented Reality (AR) applications, object tracking is a key challenge and requires a significant amount of annotation masks. As segmentation foundation models like the Segment Anything Model (SAM) begin to emerge, zero-shot segmentation requires only minimal human participation obtaining high-quality object masks. We introduce a HoloLens-Object-Labeling (HOLa) Unity and Python application based on the SAM-Track algorithm that offers fully automatic single object annotation for HoloLens 2 while requiring minimal human participation. HOLa does not have to be adjusted to a specific image appearance and could thus alleviate AR research in any application field.We evaluate HOLa for different degrees of image complexity in open liver surgery and in medical phantom experiments. Using HOLa for image annotation can increase the labeling speed by more than 500 times while providing Dice scores between 0.875 and 0.982, which are comparable to human annotators. Our code is publicly available at: https://github.com/mschwimmbeck/HOLa.
Lateral shear interferometry for shape accuracy measurements of 3D-printed micro-optics
Authors: Zhao Yanqiu , Wang Lunwei , Siegle Leander , Giessen Harald
Published: December 2024

The technique of 3D-printed micro-optics has experienced significant advancements over the last few years [1, 2]. This progressive evolution has been marked by remarkable strides in precision and miniaturization, making it particularly attractive to applications in the field of medical endoscopy. One noteworthy application entails the fabrication of micro-lenses directly on optical fibers, thereby creating endoscopic devices with unparalleled capabilities. A significant attribute of these micro-optical systems lies in their capability for precise imaging and their adept navigation through exceptionally narrow biological structures. For instance, the application of the 3D-printed endoscopy technology has facilitated insertion into the aorta of mice, as well as severely diseased human carotid arteries [2, 3]. This unprecedented level of accessibility and adaptability holds immense promise for diagnostic and therapeutic interventions in the realm of cardiovascular medicine and beyond. In the future, it may also be conceivable for micro-lenses to serve not only as imaging tools, but also as integral components of 3D-printing processes aimed at repairing damaged human tissue with bio-materials. For micro-lens production and quality control, performance assessment is invariably necessary to assure diffraction limited imaging in the different optical applications. With confocal surface profiling, only the surface shape information of micro-optics can be obtained. However, not only the shape of 3D-printed optics is relevant for its quality, but also its refractive index distribution is crucial when determining its overall optical performance. Therefore, the measurement of the wavefront is decisive in evaluating lens performance. Lateral shear interferometry presents itself as a compact and precise method for wavefront measurements. The only essential component required in the set-up is a pair of glass plates with high surface quality. Consequently, the entire set-up can be notably streamlined, as there is no requirement to construct an interferometer reference arm. This advantage facilitates the development of a notably compact set-up, making lateral shear interferometry particularly advantageous for integration with microscope and 3D-printer, despite the requirement for more complex algorithms in analyzing lateral shear interferograms. In this paper, simulation of shear interferogram fringes corresponding to wavefronts exhibiting varying aberrations are discussed. Additionally, this research encompasses measurement and analysis of shear interferograms obtained from wave fronts transmitted through different lenses. Through meticulous examination of these experimental results, the characteristics and performance of the tested optical systems are elucidated, contributing to a deeper understanding of wavefront analysis methodologies and their applicability in optical characterization studies.
Investigating dye adsorption: The role of surface-modified montmorillonite nanoclay in kinetics, isotherms, and thermodynamics
Authors: Alruwais Raja Saad
Published: December 2024

The study presents a straightforward, eco-friendly method for removing toxic dyes, such as methylene blue (MB) and acid red (AR), from aqueous solutions through solid-phase extraction using adsorption on surface-modified montmorillonite nanoclay. The nanoclay, containing 25–30 wt% methyl dihydroxyethyl hydrogenated tallow ammonium (MM-MDH nanoclay), functions as the environmentally benign adsorbent. The physical properties of MM-MDH nanoclay were characterized utilizing scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and surface area analysis. Optimal conditions for dye removal, including solution pH, nanoclay dosage, contact time, solution temperature, and ionic strength, were systematically investigated. Experimental results demonstrated that MM-MDH nanoclay effectively removed the majority of dyes within 90 min. Isotherm data indicated an adsorption capacity of 34.33 mg/g for AR dye and 20.19 mg/g for MB dye under optimal conditions. The adsorption process was analyzed kinetically and thermodynamically, revealing that the pseudo-second-order kinetic model accurately described the adsorption behavior. Thermodynamic analysis confirmed that the process was spontaneous and exothermic for AR dye and spontaneous and endothermic for MB dye. The effectiveness of MM-MDH nanoclay was further validated by removing dyes from three different real samples, demonstrating high performance in dye removal over four consecutive cycles.
Modeling the emitted carbon dioxide and monoxide gases in the gasification process using optimized hybrid machine learning models
Authors: Shen Baohua , Lu Xiaoman , Jiang Juan , Li Daoguo
Published: December 2024

The machine learning methods are hereby proposed to predict the amount of Carbon Monoxide (CO) and Carbon Dioxide (CO₂) emissions in a gasification process, which is one of the most important enabling technologies for carbon-containing materials, such as coal, biomass, and waste toward producing end products of worth, such as syngas, hydrogen, and synthetic fuels. In an attempt to support efforts for improving the emission prediction-a key criterion for enhancing efficiency and further, the environmental performance of gasification-two new advanced algorithms are being applied for the optimization of the model of a random forest: the Jellyfish Search Optimizer (JSO) and Sooty Tern Optimization Algorithm (STOA). The tuned RFJS (RF+JSO) was the best of these configurations, providing the least RMSE of 0.593 on test data and the highest R
2 on validation of 0.983, proving to be most effective for the prediction of emissions. This goes to attest that the model RFJS would be a strong tool in real-time-based carbon emissions reduction due to its effectiveness in dealing with major implications from environmental monitoring to regulation and further into sustainable energy production.
Positive Obligations to Retrofit Buildings with Third-Party Effect under Private Law as an Instrument of Public Climate Policy
Authors: Hoops Björn , Ahlinder Elisabeth , Bryła Jakub , Teruel Rosa Maria Garcia , Godt Christine , Guerry Anais , Holligan Bonnie , Janocha Tomasz , Joye Jean-François , Karens Jacco , Petersen Víðir Smári , Praduroux Sabrina , Moreno Hector Simón , Vern Flora , Van de Voorde Johan , Walsh Rachael , Zowczak Franciszek
Published: December 2024

310When incentives fail to encourage enough owners to make their buildings climate-proof, the State has to impose obligations to retrofit buildings if climate targets are to be reached. This contribution examines whether the State can employ obligations based upon agreement with third-party effect, to enforce higher energy-efficiency standards for buildings and an improved energy mix. It presents and compares the responses to two cases from eleven European jurisdictions. It shows that the majority of examined jurisdictions will allow for the State to impose positive obligations with third-party effect through a burden registered in favour of the State or a property right for the buyer. Only Dutch law would be likely to invalidate the obligation because the obligation circumvents public-law safeguards. A minority of the examined jurisdictions would not allow for a burden with positive obligations as its main content.311
The in situ green synthesis of metal organic framework (HKUST-1)/cellulose/chitosan composite aerogel (CSGA/HKUST-1) and its adsorption on tetracycline
Authors: Wang Tianhao , Wang Luyang , Liu Shun , Chen Lin , Jin Xin , Liu Haitang , Liao Xiaoyuan
Published: December 2024

In this work, a strategy of in situ 3D hierarchical porous HKUST-1/cellulose/chitosan (CSGA/HKUST-1) composite aerogels were synthesized using ethylene glycol diglycidyl ether (EGDE) as a cross-linking agent. The effect of EGDE on CSGA/HKUST-1 and the adsorption of tetracycline (TC) was investigated: the composite aerogel (CSGA) was produced by the ring-opening reaction of the epoxy group of EGDE in alkaline solution. The chemical structure of CSGA/HKUST-1 composite aerogel was characterized by FT-IR, XRD and XPS.49.33 % mass loading of CSGA1/HKUST-1 was achieved and N2 adsorption and desorption experiment showed the BET specific surface area reached 694.514 m2 g−1. SEM observed the CSGA/HKUST-1 composite aerogel pores were filled with a large number of octahedral HKUST-1 crystal particles. CSGA/HKUST-1 composite aerogel has excellent tetracycline adsorption capacity (285.7 mg g−1), and the removal efficiency remained at 92.7 % after five cycles of adsorption–desorption. The pseudo-second-order kinetic model and Langmuir model adsorption mechanism was successfully concluded. This study can provide ideas for in situ synthesis of MOFs on 3D composite aerogel to prepare adsorption materials, improve the mass loading rate of MOFs and prevent MOFs from falling off, etc., and enrich the application of MOFs materials in the treatment of antibiotic pollutants.
Uptake of Eu, Th, U, and Pu by granite and biotite gneiss in Korean fresh groundwater under oxidizing and reducing conditions
Authors: Eun Hyeonjin , Szabo Peter Gyula , Rehhorn Darlyn , Lee Seungwoo , Jo Yongheum , Altmaier Marcus , Lee Jinyoung , Gaona Xavier , Yun Jong-Il
Published: December 2024

The uptake of Eu, Th, U, and Pu by Korean granite and biotite gneiss was investigated in a series of batch experiments. Experiments were conducted under well-defined redox conditions, i.e., oxidizing (air), mildly reducing (Ar-atmosphere and buffered with hydroquinone, pe + pH ≈ 8–9), and strongly reducing (Ar-atmosphere and buffered with Na2S2O4, pe + pH ≈ 0.5–3). Radionuclide concentration, pH and E
h were systematically monitored up to t ≤ 113 days after the addition of the radionuclide. The natural content of Eu, Th and U in pristine granite and biotite gneiss materials was quantified by means of alkaline fusion. Eu exhibited moderate sorption on biotite gneiss displaying higher distribution ratios (R
d) compared to granite. This observation was possibly explained by the affinity of Ln(III)/An(III) towards biotite mineral absent in the investigated granite material. Strong sorption was observed for Th, U, and Pu in reducing systems where the predominance of the +IV oxidation state is expected. For these three systems, the strength of the uptake follows the order R
d(Pu(IV)) > R
d(U(IV)) > R
d(Th(IV)), consistent with the hydrolysis strength of the corresponding aquo-ions. A significantly weaker sorption was observed for U and Pu under oxidizing conditions, although R
d values are manifestly higher for Pu than U. Thermodynamic calculations for the oxidizing conditions predicted the predominance of U(VI) and Pu(V)/Pu(IV), explaining observed differences in retention under oxidizing conditions. These results contribute to a quantitative description and a better understanding of the retention of redox-sensitive radionuclides in crystalline host rocks. Emphasis is placed on the importance of utilizing both redox-stable probes (e.g., Eu, Th) and redox-sensitive actinides (e.g., U, Pu), as well as well-defined redox conditions for accurate predictions of radionuclide retention.
Os desafios da prática na formação inicial docente: experiência da Educação Física da UNESP de Rio Claro
Authors: Souza Neto Samuel de , Benites Larissa
Published: December 2024

Este artigo aborda as políticas educativas atuais para a formação docente. Em particular,recupera o conjunto de políticas e debates no campo educacional e suas incidências sobre os programas de formação docente e sobre os estágios em meio escolar. A experiência de Rio Claro, na forma de uma pesquisa, assim como o resultado de estudos e documentos produzidos por pesquisadores desta instituição são apresentados de forma integrada, focalizando a formação e o papel dos estágios supervisionados, dos professores supervisores, professores -colaboradores e das escolas que acolhem os estagiários. Enfim, os limites e possibilidades dos dispositivos de enquadramento de estagiários e parcerias postos em prática por esta instituição são analisados e colocados em perspectiva à luz da literatura sobre es te tema.
A organização dos estágios e o acompanhamento do desenvolvimento profissional dos estagiários em Quebec
Authors: Gervais Colette
Published: December 2024

Este texto descreve a formação para o ensino no Quebec, que se apoia em um referencial de competências profissionais e que deixa bastante espaço para as experiências de estágio. Elementos da organização dos estágios são apresentados, destacando -se tendências a respeito da contribuição dos formadores e do desenvolvimento profissional dos estagiários, baseando-se em resultados de estudos. Um quadro de referência para a formação dos formadores de estagiários, recentemente desenvolvido, é apresentado. Por fim, segue-se um questionamento quanto às perspectivas teóricas subjacentes ao desenvolvimento das experiências de estágio.