bluuebunny/crossref_metadata_2025 huggingface dataset:
Infusion Room–Based Transition to Practice Model for Teaching Cancer Systemic Therapy Management
Authors: Duff Jennifer M. , Markham Merry-Jennifer , George Thomas J. , Close Julia L.
Published: September 2017

Purpose:

Oncology training requirements mandate that fellows demonstrate competence in delivery of cancer therapeutics, understand clinical indications for treatment, and manage toxicities by completion of training. An academic training environment may hinder fellows’ engagement in prescribing, monitoring, and adjusting cancer therapy; thus, trainees may complete their fellowship with limited experience in developing such critical skills. To provide hands-on experience in cancer systemic therapy management, we created a novel infusion room–based rotation in the final year of training; here we report the structure, logistics, and evaluation of this innovative program.

Methods:

In 2004, The University of Florida Hematology Oncology Fellowship Program created an outpatient infusion room rotation called Transition to Practice (TTP). We surveyed 20 graduates of the program to assess the ability of the rotation to teach skills necessary for systemic therapy management and identify which fellowship rotations had an impact on their readiness to practice independently.

Results:

Nineteen graduates completed the survey. TTP was rated highest for promoting independence in making decisions related to therapy and adjustment to the treatment plan. It was less valuable in teaching the financial aspects of cancer therapy encounters. The Veterans Affairs Medical Center continuity clinic and the TTP rotation were highly regarded for preparing graduates to practice oncology independently.

Conclusion:

We consider the TTP model an effective learning environment for oncology trainees to develop the essential skill set for managing cancer systemic therapy on the basis of this single-institution analysis of recent graduates. This model could be applied to training other oncology professionals, such as advanced practice providers, who are new to the field.
Anaesthetic-associated cardiac arrhythmias in dogs and cats: part 1
Authors: Miller Chris , Flaherty Derek
Published: September 2017

Perioperative arrhythmias are frequently observed in both healthy and sick dogs and cats due to a variety of different aetiologies. Basic knowledge of the cardiovascular system and the effect that arrhythmias may have is necessary to know how and when to treat these, and when to simply monitor. Differentiation between common, benign arrhythmias and cardiovascularly detrimental arrhythmias is important for appropriate management. Recognition of certain arrhythmias that have the potential to progress rapidly and potentially fatally is of vital importance. The aim of this first of two articles is to give an overview of the potential adverse effects of arrhythmias during the peri-anaesthetic period; to discuss when arrhythmias should be treated; and to consider in greater depth recognition and management of bradyarrhythmias. Part two of this series will discuss tachyarrhythmias.
Treatment of gallbladder disease in dogs and cats
Authors: Kilpatrick Scott , Uetsu Yuki , Bell Andrew
Published: September 2017

Gallbladder diseases are relatively uncommon in small animals. Clinical conditions of the gallbladder include cholycystitis, gallbladder mucocele, cholelithiasis and neoplasia. Gallbladder diseases are more common in older animals and the clinical presentation of disease is similar to other gastrointestinal or hepatic diseases. Haematology and biochemistry often demonstrate nonspecific abnormalities including leucocytosis, neutrophilia, increased liver enzymes and hyperbilirubineamia. Endocrine diseases such as hypothyroidism and hyperadrenocorticism are often found concurrently with gallbladder diseases. Ultrasound is a useful diagnostic tool for the investigation of gallbladder diseases. Ultrasound-guided cholecystocentesis can also be performed and its complication rate is low. Medical treatments commonly include antibiotics and choleretics. The efficacy of medical treatment has not been totally determined and surgical intervention is often required as a definitive treatment. Morbidity and mortality of surgical intervention is relatively high, due to complications such as peritonitis.
Lending a paw: locum tips and tricks
Authors: Parkinson Kate
Published: September 2017

Locum work is becoming increasingly popular throughout the UK. Many veterinary surgeons will work as locums at some stage in their careers. Locum work allows plenty of flexibility and can offer travel opportunities, endless variety, and extra money. However, locum veterinary surgeons do not have a stable income, may find it difficult to get certain types of loans, often have long commutes, and are responsible for their own professional expenses and accounting. Many cases will be lost to follow-up, and it can be difficult not being part of a permanent practice team. You may work through a limited company or through an umbrella company, which is often organised through a locum agency. Most locum veterinary surgeons in the UK find work through locum agencies, although freelance work is also possible. The author has found locum work personally and professionally rewarding, and would recommend freelance locum work as an alternative career option.
Research roundup: September 2017
Authors: Som Rita
Published: September 2017

In brief

Rheumatoid arthritis patients with anxiety and depression favour talking therapy over medication Non-medical prescribers are adhering to government guidelines on antibiotic prescribing and prescribing fewer antibiotics Sleep disturbance in people with diabetes is thought to form a physiological cycle Some age-related health declines might be due to poorer sleep quality
Kajian Perilaku Dinamik Struktur Jembatan Penyeberangan Orang (JPO) 2 Lantai Akibat Beban Manusia yang Bergerak
Authors: Indarto Himawan , Pudjianto Bambang , Nurhuda Ilham
Published: September 2017

Jembatan Penyeberangan Orang (JPO) dengan bentang panjang dan JPO dengan lantai bertingkat, mulai banyak di bangun di kota-kota besar di Indonesia. JPO dibangun sebagai sarana penghubung dari satu bangunan ke bangunan lainnya, sekaligus berfungsi sebagai jembatan penyeberangan lalu lintas yang berada di bawahnya. Bentuk struktur yang langsing membawa konsekuensi, bahwa struktur JPO rentan terhadap masalah getaran. Masalah munculnya getaran pada struktur JPO pada saat orang melewati jembatan, akan menyebabkan ketidak-nyamanan bagi pengguna jalan. Getaran yang muncul pada JPO dapat diakibatkan oleh karena frekuensi getar alami dari struktur JPO yang terlalu besar, atau terjadinya resonansi yang diakibatkan karena frekuensi getar beban yang melewati JPO mendekati frekuensi getar alami dari struktur. Pada perencanaan struktur JPO, asumsi bahwa beban pejalan kaki merupakan beban statik dengan hanya satu arah komponen beban kearah vertikal, adalah tidak tepat. Beberapa penelitian telah membuktikan bahwa beban orang yang bergerak merupakan beban dinamik yang mempunyai tiga komponen arah beban, yaitu arah vertikal, longitudinal, dan lateral. Dari hasil penelitian diketahui bahwa, beban pejalan kaki yang bersifat dinamik pada struktur JPO 2 Lantai, akan menyebabkan deformasi struktur 1,55 kali lebih besar  dibandingkan dengan deformasi yang didapat dari analisis statik. Hal ini kiranya perlu diperhatikan di dalam perencanaan struktur JPO, agar didapatkan perencanaan yang memenuhi syarat kekuatan dan kekakuan, sehingga tidak menyebabkan terjadi permasalahan getaran pada saat digunakan.
Kajian Kerentanan Ekosistem Pesisir Kabupaten Demak Berdasar Perubahan Garis Pantai dengan Teknologi Penginderaan Jauh dan Sistem Informasi Geografis
Authors: Sasmito Bandi , Suprayogi Andri
Published: September 2017

Pesisir dan pantai Kabupaten Demak terdapat beragam ekosistem seperti mangrove, ikan, terumbu karang, burung pemakan ikan, udang, dan sebagainya. Sedangkan garis pantai di Kabupaten Demak mengalami perubahan yang disebabkan oleh proses abrasi dan akresi yang terpicu karena aktivitas manusia yang intensif di wilayah pesisir. Abrasi dan akresi yang terjadi dirasa mengancam keberagaman ekosistem, sehingga perlu dilakukannya perlindungan dan pelestarian kawasan pesisir dan pantai. Penelitian ini menggunakan metode berupa penggabungan teknologi Penginderaan Jauh dan Sistem Iinformasi Geografis (SIG) untuk mengukur kerentanan wilayah pesisir dengan memanfaatkan klasifikasi kerentanan pesisir dari Environmental Sensitivity Index (ESI) Maps serta perhitungan laju perubahan garis pantai menggunakan perangkat lunak Digital Shoreline Analysis System (DSAS). Hasil yang diharapkan dari penelitian ini adalah 1. Deteksi perubahan garis pantai di Kabupaten Demak dalam kurun waktu 5 (lima) tahun terakhir (2011-2015), 2. Pemodelan trend perubahan garis pantai 5 (lima) tahun kedepan (2016-2020), dan 3. Deteksi ekosistem pesisir Kabuaten Demak mana saja yang terdampak akibat perubahan garis pantai 5 tahun terakhir (2011-2015), dan trend 5 tahun kedepan (2016-2020).
Spatial resolution of electrical source localization depends on inter-electrode spacing and signal-to-noise ratio
Authors: Nguyen Martin , Schanze Thomas
Published: September 2017

Extracellular recordings of electrical neuronal sources with non-planar multichannel microelectrodes promise a high spatio-temporal resolution. We have developed signal-based algorithms, simulations and models to inversely estimate neuronal source positions and electrical properties by using multi-sensor recorded extracellular action potentials (EAP). Here, we analyse the dependence of electrode configurations on the position estimation by simulations. Estimations were simulated for various inter-electrode spacings, electrode-source distances and signal-to-noise ratios. The results show that inverse estimation depends on the electrode size or rather on the inter-electrode spacing. We find, as a rule, the larger the spacing, the larger the eligible source location area, but estimation quality of sources which are in the proximity of an electrode contact decreases. In addition, noise worsen the estimation and decreases the assessable distance between source and electrode. Thus, multichannel micro-electrodes should be selected towards signal and spatial sensitivity requirements.
Development of a tool-kit for the detection of healthy and injured cardiac tissue based on MR imaging
Authors: Westphal Philip , Hilbert Sebastian , Unger Michael , Chalopin Claire
Published: September 2017

Planning of interventions to treat cardiac arrhythmia requires a 3D patient specific model of the heart. Currently available commercial or free software dedicated to this task have important limitations for routinely use. Automatic algorithms are not robust enough while manual methods are time-consuming. Therefore, the project attempts to develop an optimal software tool. The heart model is generated from preoperative MR data-sets acquired with contrast agent and allows visualisation of damaged cardiac tissue. A requirement in the development of the software tool was the use of semi-automatic functions to be more robust. Once the patient image dataset has been loaded, the user selects a region of interest. Thresholding functions allow selecting the areas of high intensities which correspond to anatomical structures filled with contrast agent, namely cardiac cavities and blood vessels. Thereafter, the target-structure, for example the left ventricle, is coarsely selected by interactively outlining the gross shape. An active contour function adjusts automatically the initial contour to the image content. The result can still be manually improved using fast interaction tools. Finally, possible scar tissue located in the cavity muscle is automatically detected and visualized on the 3D heart model. The model is exported in format which is compatible with interventional devices at hospital. The evaluation of the software tool included two steps. Firstly, a comparison with two free software tools was performed on two image data sets of variable quality. Secondly, six scientists and physicians tested our tool and filled out a questionnaire. The performance of our software tool was visually judged more satisfactory than the free software, especially on the data set of lower quality. Professionals evaluated positively our functionalities regarding time taken, ease of use and quality of results. Improvements would consist in performing the planning based on different MR modalities.
Improving subviral particle tracks in fluoroscopic image sequences by global motion compensation
Authors: Rausch Andreas , Schanze Thomas
Published: September 2017

Automatic detection and tracking of subviral particles in image sequences is an indispensable supportive method for modern medicine research programs. This paper describes the development of a highly adaptable camera-to-world system motion invariant tracking algorithm. A translation compensation is obtained by cross correlations. Particles are detected by an implemented existing algorithm. The detected particles are linked by solving a Linear Assignment Problem. For highly stable results the tracks are improved by Kalman filtering. The algorithm is tested on simulated sequences. The results show a great ability for stable tracking.
Removing noise in biomedical signal recordings by singular value decomposition
Authors: Schanze Thomas
Published: September 2017

Noise reduction or denoising is the process of removing noise from a signal. If some signal properties are known linear filtering is often useful. Fourier, wavelet and similar transform approaches remove unwanted signal components in the codomain. For this, predefined eigen-functions, e.g. wavelets, are used. Here we use singular value decomposition in order to compute a signal driven re-presentation (eigendecompositon). By removing unwanted components of the representation the signal can be denoised. We introduce the new method, apply it to signals and discuss its properties.
Multifunctional surface probe for less invasive stimulation of sacral somatic and autonomic outflow under EMG feedback control
Authors: Kauff Daniel W. , Moszkowski Tomasz , Ruff Roman , Kneist Werner
Published: September 2017

Invasive electric stimulation of sacral somatic and autonomic outflow is used for treatment of urinary and anorectal functional disturbances and selective monitoring of the autonomic nerve-sparing technique in pelvic surgery, the so called pelvic intraoperative neuromonitoring. The aim of this experimental study was to investigate a less invasive approach for simultaneous stimulation of sacral somatic and autonomic outflow and concomitant recording of feedback.

A newly developed multifunctional surface probe for simultaneous transrectal stimulation and electromyography (EMG) of external (EAS) and internal anal sphincter (IAS) was investigated in a consecutive series of six male pigs. The probe (cathode) was designed for intra-anal/-rectal application. An additional surface anode was placed on the animals´ back at the level of the sacrum. Each animal underwent autonomic nerve-sparing low anterior rectal resection. The transrectal stimulations followed a standardized protocol. Further direct stimulation of the surgically exposed pelvic autonomic nerves was carried out with a hand-guided bipolar microfork probe.

In all six experiments, the transrectal stimulation resulted in significantly increased EMG signals of the somatically innervated EAS (21.0 μV (interquartile range (IQR): 17.8; 64.4) before stimulation vs. 375.8 μV (IQR: 103.4; 895.9) during stimulation, p = 0.004) and autonomically innervated IAS (35.1 μV (IQR: 27.9; 41.7) before stimulation vs. 1115.7 μV (IQR: 420.1; 2920.3) during stimulation, p = 0.008). Subgroup analysis of the observed IAS EMG signals under transrectal stimulation and hand guided direct stimulation revealed no significant differences between both methods (70.5 μV (IQR: 31.5; 322.7) vs. 320.3 μV (IQR: 204.0; 358.0), p = 0.109).

The newly developed multifunctional surface probe enabled successful transrectal stimulation of sacral somatic and autonomic outflow under EMG feedback control. The clinical value of this less invasive approach for the treatment of functional disturbances needs further investigations.
Realization of a multi-layer EIT-system
Authors: Busch Christoph , Schullcke Benjamin , Moeller Knut
Published: September 2017

Electrical Impedance Tomography (EIT) is an imaging technique used for monitoring of ventilation distribution in the lung. Small alternating currents are injected and resulting voltages are measured on the body surface with electrodes fixed around the thorax. Two-dimensional EIT (2D-EIT) is the most common technique in clinical applications but enables visualization of only one horizontal slice of the thorax. However, additional information in the cranio-caudal direction is necessary to more comprehensively assess the ventilation distribution.

3D-EIT systems address this issue, but clinically approved systems are not yet available. The aim of this study is to realize a multi-layer EIT-system with several electrode planes. An approved EIT system functions as basis for this development (PulmoVista 500, Dräger, Lübeck, Germany). Two planes were used for the technical realization of the multi-layer EIT-system. The alternation between the planes was realised using analog switches, which were controlled via a frequency generator and transfer the injected current and the measured voltages between the different electrode planes and the EIT device. The multi-layer EIT-System was applied to a phantom tank for first pilot measurements.

Results on the phantom tank with non-conductive targets at different heights reveal that the system is capable of providing information in the cranio-caudal direction. The high frame rates of EIT images combined with the high switching speed of the used analog switches enable real-time acquisition of ventilation at different thoracic planes. Thus, the modified EIT device makes it possible to comprehensively monitor the redistribution of air in the lungs during a breathing cycle, not only in a single plane, but also in the cranio-caudal direction.
tISM - a transportable integrating sphere setup for standardized measurements of blood and tissue phantoms
Authors: Wegerich Philipp , Rackebrandt Klaas , Gehring Hartmut
Published: September 2017

The development of an optical sensor for non-invasive measurements in humans requires a test setup, where the optical properties of tissue and blood can be adjusted and measured standardized. The goal of this work is to develop a simplified device based on an integrating sphere setup to evaluate the optical properties of tissue and blood phantoms with respect to static as well as flow conditions. Furthermore, the measurement system is intended to be used at different locations such as laboratories and operating theaters. We evaluate the absorption μa and reduced scattering μs' coefficients of specimens, with the developed integrating sphere setup. The measurement is regulated by a microcontroller for averaging and processing the data. The system is housed in a lightproof box and powered by a battery and therefore transportable. Due to this construction, no calibration is necessary between transports of the system. Calculations are executed with the inverse adding doubling algorithm. In order to basically calibrate and evaluate the setup before first transportation, a dilution series with Intralipid and India ink serve for the test. The results were consistent with precedent studies (mean absolute deviation for μs' of 0.75 mm-1) and demonstrate that this method might be able to produce liquids with adjustable optical properties, as required for further research. Furthermore, a first dilution series of heparinized heamoglobin (5 to 15 g/dl) with oxygen saturation of 98 % was measured with this system under flow conditions.

We observed a linear increase of μa and μs' with the increment of the haemoglobin concentration. As light sources, laser diodes in the range from 780 to 980 nm were introduced. Static and flow measurements indicated that the system is capable for evaluating optical properties under the selected conditions.
Variability of intra-aneurysmal hemodynamics caused by stent-induced vessel deformation
Authors: Voß Samuel , Berg Philipp , Janiga Gabor , Skalej Martin , Beuing Oliver
Published: September 2017

Clinical observation revealed deformations of the local vasculature due to implanted devices related to treatment of intracranial aneurysms. Pre- and post-interventional image data is reviewed and segmented. Based on Computational Fluid Dynamics (CFD) the effect of the vessel deformation on the intra-aneurysmal hemodynamics is investigated. The simulations incorporate the vessel trees with aneurysm excluding the device itself in order to consider the isolated effect of geometric modifications. As a result, the aneurysm inflow jet is redirected, changing the local flow quantities. Finally, a neck inflow rate reduction of 52.5 % is archived. Thus, a targeted vessel straightening as a novel tool for treatment planning appear to be an idea worth to discuss in the community.
Characterization of online high dynamic range imaging for laser-driven ion beam diagnostics using visible light
Authors: Englbrecht Franz , Balling Felix , Rösch Thomas Federico , Würl Matthias , Lindner Florian Hans , Parodi Katia , Schreiber Jörg
Published: September 2017

Laser-driven acceleration of particle beams is an emerging modality under research for biomedical applications. The spatially resolved diagnostics of laser-accelerated proton bunches is crucial for their application. The RadEye detector, featuring up to 10 cm x 5 cm area of online complementary metal-oxide-semiconductor (CMOS) detector made of 48 μm pixels, is established for x-ray, proton and ion beam diagnostics. We exploit the usually undesired ‘Image lag’ phenomenon of incomplete pixel reset to generate 2D-images with a larger dynamic range than the single frame range of 12-bit. Using 532 nm laser pulses and computer simulations for single-slit diffraction, calibration factors to stack multiple readouts were successfully derived to quantitatively reconstruct spatial information about an optical beam and hence extend the dynamic range of the detector compared to a single frame. The final goal is focus quantification for a permanent magnet quadrupole system for protons and terawatt (TW-class) laser focus diagnostics.
Long-term stable surface modification of DLC coatings
Authors: Gotzmann Gaby
Published: September 2017

The use of coatings based on diamond like carbon (DLC) for medical applications was established during the last years. Main advantages of these coatings are its high hardness, good wear and friction behavior and its biocompatibility. Using low-energy electron-beam treatment, we addressed the surface modification of DLC coatings. The aim was to generate new biofunctional surface characteristics that are long-term stable.

Electron-beam modification resulted in significantly increased surface hydrophilicity, giving rise to the conclusion, that biological reaction on these surfaces will also be influenced by the modification. Furthermore, the stability of the surface modification was investigated. Therefore, the modified samples were stored for 8 weeks under ambient conditions. Additionally, the samples were stored in physiological saline solution at 37°C for 8 weeks. The stability of the modification was analyzed by contact angle measurement confirming no changes over the whole period of storage. In addition, the stability against standard cleaning and sterilization procedures was investigated. The durability of the modification to withstand these cleaning procedures was also proven.

With these findings, the low-energy electron-beam modification seems to be a suitable tool for surface modification of DLC coatings. Thereby, the very good long-term stability is a great improvement in comparison to conventional surface modification methods like plasma treatment. In order to investigate the suitability of the modified coatings for biomedical applications, the cellular response was investigated using human fibroblasts, revealing a significantly reduced cell count on modified surfaces while maintaining their biocompatibility. By modification of the DLC surfaces, it is possible to adapt the cell adhesion on the treated surface areas. These findings demonstrate electron-beam treatment to be applicable for partial surface modification and functionalization within biomedical applications.
Microfluidic system for enhanced cardiac tissue formation
Authors: Busek Mathias , Kolanowski Tomasz , Grünzner Stefan , Steinfelder Christian , Guan Kaomei , Sonntag Frank
Published: September 2017

Hereby a microfluidic system for cell cultivation is presented in which human pluripotent stem cell-derived cardiomyocytes were cultivated under perfusion. Besides micro-perfusion this system is also capable to produce well-defined oxygen contents, apply defined forces and has excellent imaging characteristics. Cardiomyocytes attach to the surface, start spontaneous beating and stay functional for up to 14 days under perfusion. The cell motion was subsequently analysed using an adapted video analysis script to calculate beating rate, beating direction and contraction or relaxation speed.
Fast parallel quantification of dual drug systems via UV-VIS spectrometry – a case study with antibiotic substances
Authors: Eickner Thomas , Reske Thomas , Illner Sabine , Schmitz Klaus-Peter , Martin David P. , Grabow Niels
Published: September 2017

Implant-based drug delivery necessitates a rigorous quantitative assessment and quality control of the drug release behavior. In this context, a fast simultaneous UV-VIS spectrometer quantification method was developed for an antibiotic dual drug system. Particular challenges arose from interfering spectra, as well as different solubility and stability of the drugs. The test system used here consists of the antibiotics Minocycline and Rifampin, which are used as an antibiotic combination approach in a growing number of device applications, such as impregnation of venous or urethral catheters. Two suitable wavelengths for this test system were identified. At a wavelength of 475 nm only Rifampin shows an absorption maximum, which was used to determine the concentration of Rifampin in the mixture. At 245 nm both antibiotics have a local extremum, a maximum for Minocycline, and a minimum for Rifampin. The developed UV-VIS spectrometer method for Rifampin and Minocycline dissolved in Sörensen buffer showed good results for small concentrations of Minocycline. For stability tests, a mixture of both antibiotics (1:1) was stored at 37°C for up to 144 h in NaCl solution (0.9%), and in Sörensen buffer, respectively. At defined time points, UV-VIS spectra were recorded, and feasibility of this quick simultaneous quantification method for these two widely used antibiotics was demonstrated.
Standard manual reprocessing of angiographic systems in the hybrid OR
Authors: Buhl Sebastian , Werner Carina , Bulitta Clemens
Published: September 2017

A current FDA guidance demands the validation of cleaning and disinfecting protocols even for non-sterile medical devices. The aim of this work is to clarify whether this is already possible using the guidance itself as well as the German DIN EN ISO 17664. An angiography system (Artis Zeego / Pheno - Siemens) was selected as a test object for the validation of a cleaning and disinfection protocol for medical devices in a hybrid operating room. In pilot study prior to the trial, critical points of the system were evaluated by means of questionnaires to clinical users (OTA, surgical technicians). An initial assessment of the in-house cleaning protocols used in the hospitals was done by using a fluorescence assay. The microbiological examination took place subsequently by contact plates and swabbing to determine the amount and type of germs on the surfaces of the system. These experiments were done at three different clinical sites. It was found that there was a significant germ count on several surfaces of the product even after in-house cleaning and disinfection (C&D). After application of an enhanced C&D plan, these germs could be greatly reduced at all verified sites. In addition, it could be shown that DIN EN ISO 17664 can in principle be applied to non-sterile medical products.
Evaluation of an automated analysis for pain-related evoked potentials
Authors: Wulf Michael , Eitner Lynn , Felderhoff Thomas , Özgül Özüm , Staude Gerhard , Maier Christoph , Knopp Andreas , Höffken Oliver
Published: September 2017

This paper presents initial steps towards an auto-mated analysis for pain-related evoked potentials (PREP) to achieve a higher objectivity and non-biased examination as well as a reduction in the time expended during clinical daily routines. While manually examining, each epoch of an en-semble of stimulus-locked EEG signals, elicited by electrical stimulation of predominantly intra-epidermal small nerve fibers and recorded over the central electrode (Cz), is in-spected for artifacts before calculating the PREP by averag-ing the artifact-free epochs. Afterwards, specific peak-latencies (like the P0-, N1 and P1-latency) are identified as certain extrema in the PREP’s waveform. The proposed automated analysis uses Pearson’s correlation and low-pass differentiation to perform these tasks. To evaluate the auto-mated analysis’ accuracy its results of 232 datasets were compared to the results of the manually performed examina-tion. Results of the automated artifact rejection were compa-rable to the manual examination. Detection of peak-latencies was more heterogeneous, indicating some sensitivity of the detected events upon the criteria used during data examina-tion.
Neuro control – using neuro monitoring data to control networked active instruments
Authors: Dietz Christian , Pfeiffer Jonas H. , Dingler Max E. , Lüth Tim C.
Published: September 2017

Intraoperative neurophysiological monitoring (IONM) can be used to monitor the neural integrity and help the surgeon to reduce iatrogenic patient damage. We present a networked digital assistance system based on real-time IONM data. The system automatically reduces the power of active medical ablation instruments when they endanger neural structures. We integrated a nerve monitor into a real-time network of medical devices. In doing so, neurophysiological signals are available to all connected medical devices in real-time. With the IONM data a so-called function module Neuro Control calculates and controls the maximum allowed power for active instruments like an ultrasonic dissector.
Time-domain analysis of distortion-product otoacoustic emissions using a hydrodynamic cochlea model
Authors: Zelle Dennis , Dalhoff Ernst , Gummer Anthony W.
Published: September 2017

As a by-product of nonlinear amplification in the cochlea, the inner ear emits sound waves in response to two tones with different frequencies. These sound waves are measurable in the ear canal as distortion-product otoacoustic emissions (DPOAEs). DPOAEs putatively consist of two components emerging at different locations in the cochlea. Wave interference between the two components limits the accuracy of DPOAEs as a noninvasive measure of cochlear function. Using short stimulus pulses instead of continuous stimuli, the two DPOAE components can be separated in the time domain due to their different latencies. The present work utilizes a nonlinear hydrodynamic cochlea model to simulate short-pulse DPOAEs in the time domain. When adding irregularities to the mechanical parameters of the model, the simulated DPOAE signals show two distinguishable components and long-lasting beat tones, similar to band-pass filtered experimental data from normal-hearing human subjects. The model results suggest that the beat tones can occur solely due to interference of the coherent-reflection component with the fading nonlinear-distortion component.
Radiofrequency applicator concepts for simultaneous MR imaging and hyperthermia treatment of glioblastoma multiforme
Authors: Oberacker Eva , Kuehne Andre , Nadobny Jacek , Zschaeck Sebastian , Weihrauch Mirko , Waiczies Helmar , Ghadjar Pirus , Wust Peter , Niendorf Thoralf , Winter Lukas
Published: September 2017

Glioblastoma multiforme is the most frequent and most aggressive malignant brain tumor with de facto no long term curation by the use of current multimodal therapeutic approaches. The efficacy of brachytherapy and enhancing interstitial hyperthermia has been demonstrated. RF heating at ultrahigh fields (B0=7.0T, f=298MHz) has the potential of delivering sufficiently large thermal dosage for hyperthermia of relatively large tumor areas. This work focuses on electromagnetic field (EMF) simulations and provides realistic applicator designs tailored for simultaneous RF heating and MRI. Our simulations took advantage of target volumes derived from patient data, and our preliminary results suggest that RF power can be focused to both a small tumor area and a large clinical target volume.
Heart rate from face videos under realistic conditions for advanced driver monitoring
Authors: Pilz Christian S. , Zaunseder Sebastian , Canzler Ulrich , Krajewski Jarek
Published: September 2017

The role of physiological signals has a large impact on driver monitoring systems, since it tells something about the human state. This work addresses the recursive probabilistic inference problem in time-varying linear dynamic systems to incorporate invariance into the task of heart rate estimation from face videos under realistic conditions. The invariance encapsulates motion as well as varying illumination conditions in order to accurately estimate vitality parameters from human faces using conventional camera technology. The solution is based on the canonical state space representation of an Itô process and a Wiener velocity model. Empirical results yield to excellent real-time and estimation performance of heart rates in presence of disturbing factors, like rigid head motion, talking, facial expressions and natural illumination conditions making the process of human state estimation from face videos applicable in a much broader sense, pushing the technology towards advanced driver monitoring systems.
Forecasting transient sleep episodes by pupil size variability
Authors: Schumann Andy , Ebel Juliane , Bär Karl-Jürgen
Published: September 2017

The ability to predict when a person is about to fall asleep is an important challenge in recent biomedical research and has various possible applications. Sleepiness and fatigue are known to increase pupillary fluctuations and the occurrence of eye blinks. In this study, we evaluated the use of the pupil diameter to forecast sleep episodes of short duration (>1s). We conducted multi-channel physiological and pupillometric recordings (diameter, gaze position) in 91 healthy volunteers at rest in supine position. Although they were instructed to keep their eyes open, short sleep episodes were detected in 20 participants (16 males, age: 26.2±5.6 years), 53 events in total. Before each sleep event, pupil size was extracted in a window of 30s (without additional sleep event). Mean pupil diameter and its standard deviation, Shannon entropy and wavelet entropy in the first half (15s) were compared to the second half of the window (15s). Linear and nonlinear measures demonstrated an elevation of pupil size variability before sleep onset. Most obviously, WE and SD increased significantly from 0.054±0.056 and 0.38±0.16 mm to 0.113±0.103 (T(102)=2.44, p<0.001) and 0.46±0.18 mm (T(104)=3.67, p<0.05) in the second half of each analysis window. We were able to identify 83% of the pre-sleep segments by linear discriminant analysis. Although our data was acquired in an experimental condition, it suggests that pupillary unrest might be a suitable predictor of events related to transient sleep or inattentiveness. In the future, we are going to involve the other recorded physiological signals into the analysis.
Optimizing a perfusion CT protocol for head and neck cancer
Authors: Stüssi Anja , Bogowicz Marta , Weichselbaumer Verena , Veit-Haibach Patrick , Riesterer Oliver , Guckenberger Matthias , Tanadini-Lang Stephanie
Published: September 2017

Perfusion computed tomography (CTP) images tumor angiogenesis and can assess tumor aggressiveness. However, the CTP examinations are dose intensive. This study aimed to optimize a routinely used CTP protocol for the head and neck region in oncology in order to reduce the effective dose to the patient and simultaneously achieve the same image quality.

The Alderson phantom was scanned on a GE Revolution CT scanner. A scan with our standard protocol for head and neck cancer patients was used (100kV, 80mAs, 5mm slice thickness and backprojection algorithm) and in seven predefined regions (ROI) the signal to noise ratio (SNR) was measured. For the dose optimized protocol, the tube voltage was lowered and the mAs adaptation protocol was used. To improve image quality different percentage of an adaptive statistical iterative reconstruction (ASiR) was applied. For a better resolution we set the slice thickness to 2.5 mm. The mAs adaption range and the percentage of the ASiR reconstruction were varied until we found a combination with the same median SNR in the seven defined ROIs as for our old protocol. For the old and the optimized protocol dose measurements were performed using 25 LiF-TLDs. Organ doses were calculated and the effective dose was determined based on the weighting factors of ICRP103.

The optimized scanning protocol used a voltage of 80kV, a mAs range between 15 and 80, a noise level of 10%, and 50% ASiR reconstruction. The median SNR ratio was slightly better (14% better SNR) with the new protocol. An effective dose of 8 mSv was measured with the original protocol and 4 mSv with the optimized scanning protocol. For organs in the scanning field the dose was reduced by a factor of 2 and outside the field by a factor of 2.2.

Advanced reconstruction algorithms allow a significant dose reduction and an improvement of image resolution, while maintaining the image quality.
A multi-institutional survey evaluating patient related QA – phase II
Authors: Teichmann Tobias , Salz Henning , Schwedas Michael , Howitz Simon , Wiezorek Tilo
Published: September 2017

In phase I of the survey a planning intercomparison of patient-related QA was performed at 12 institutions. The participating clinics created phantom based IMRT and VMAT plans which were measured utilizing the ArcCheck diode array. Mobius3D (M3D) was used in phase II. It acts as a secondary dose verification tool for patient-specific QA based on average linac beam data collected by Mobius Medical Systems. All Quasimodo linac plans will be analyzed for the continuation of the intercomparison. We aim to determine if Mobius3D is suited for use with diverse treatment techniques, if beam model customization is needed. Initially we computed first Mobius3D results by transferring all plans from phase I to our Mobius3D server. Because of some larger PTV mean dose differences we checked if output factor customization would be beneficial. We performed measurements and output factor correction to account for discrepancies in reference conditions. Compared to Mobius3D's preconfigured average beam data values, these corrected output factors differed by ±1.5% for field sizes between 7x7cm2 and 30x30cm2 and to −3.9% for 3x3cm2. Our method of correcting the output factors turns out good congruence to M3D's reference values for these medium field sizes.
Electrospinning of polyimide nanofibres – effects of working parameters on morphology
Authors: Kohse Stefanie , Grabow Niels , Schmitz Klaus-Peter , Eickner Thomas
Published: September 2017

The use of the electrospinning technique is a promising and versatile method for producing fibrous nonwovens from various polymers. Here we present fibre formation via direct electrospinning of a soluble polyimide, a class of polymers that is typically insoluble. In this study solution parameters as the solvent and the polymer concentration are investigated. Furthermore relevant process parameters are varied for optimization of the performance. The presented data indicate polyimide as a promising material for the fabrication of nanofibrous nonwovens via direct electrospinning.
Cyclic stress-strain behavior of polymeric nonwoven structures for the use as artificial leaflet material for transcatheter heart valve prostheses
Authors: Arbeiter Daniela , Brandt-Wunderlich Christoph , Siewert Stefan , Kohse Stefanie , Pfensig Sylvia , Schmitz Klaus-Peter , Grabow Niels
Published: September 2017

Xenogenic leaflet material, bovine and porcine pericardium, is widely used for the fabrication of surgically implanted and transcatheter heart valve prostheses. As a biological material, long term durability of pericardium is limited due to calcification, degeneration and homogeneity. Therefore, polymeric materials represent a promising approach for a next generation of artificial heart valve leaflets with improved durability. Within the current study we analyzed the mechanical performance of polymeric structures based on elastomeric materials. Polymeric cast films were prepared and nonwovens were manufactured in an electrospinning process. Analysis of cyclic stress-strain behavior was performed, using a universal testing machine. The uniaxial cyclic tensile experiments of the elastomeric samples yielded a non-linear elastic response due to viscoelastic behavior with hysteresis. Equilibrium of stress-strain curves was found after a specific number of cycles, for cast films and nonwovens, respectively. In conclusion, preconditioning was found obligatory for the evaluation of the mechanical performance of polymeric materials for the use as artificial leaflet material for heart valve prostheses.
Automatic particle analysis by Raman spectroscopy – evaluation of sample preparation and optimum background material
Authors: Kurzhals Anja , Teske Michael , Reske Thomas , Eickner Thomas , Grabow Niels , Schmidt Wolfram , Schmitz Klaus-Peter
Published: September 2017

The particle generation of medical implants and drug coated balloons (DCB) is evaluated by simulating the implantation process and collecting the released particle material. In addition to size and particle counts their material composition is of interest. Raman spectroscopy and micros-copy are established methods for chemical identification. For the manual analysis of the particles different filter or rather background materials are suitable because different require-ments in height and intensity of the spectra can be compen-sated by the user. The aim of this study was to find suitable background materials for automatic particle identification.

Raman analysis of background and spherical polystyrene standard particles on filters and plain surfaces was performed manually to receive evaluable spectra for automation. Auto-matic analysis was done by a) single-point spectrum meas-urement using the coordinate list of all particles, and b) scan-ning a large sample area pixel by pixel measuring back-ground and particles.

For automatic analysis with method a) the polycarbonate membrane provided best results. With method b) the polysty-rene spectrum of the particles could be found on both plain surfaces and the polycarbonate membrane. Influences from the background spectrum could be kept small by thoroughly defining the focal plane with a wavelength specific autofocus mode for method a) and manually for method b).
Beat-to-beat blood pressure measurement from instantaneous harmonic phase-shifts in non-invasive photoplethysmographic signals
Authors: Kern Fabian , Bernhard Stefan
Published: September 2017

The state-of-the-art blood pressure measurement is beside common cuff-based methods the cuff-less estimation of pulse-transit-time, which is the time a blood pressure wave requires to travel from left ventricle of the heart to another peripheral point in the cardiovascular system. Within this work we present a novel estimation method for cuff-less blood pressure measurement by analysing a single photoplethysmographic signal in the frequency domain. The harmonic phase-shift of the fundamental frequency and the first harmonic within the photoplethysmographic signal has proven a strong correlation of r = 0.8514 and r = 0.9315 with systolic and diastolic blood pressure respectively.
EOG feature relevance determination for microsleep detection
Authors: Golz Martin , Wollner Sebastian , Sommer David , Schnieder Sebastian
Published: September 2017

Automatic relevance determination (ARD) was applied to two-channel EOG recordings for microsleep event (MSE) recognition. 10 s immediately before MSE and also before counterexamples of fatigued, but attentive driving were analysed. Two type of signal features were extracted: the maximum cross correlation (MaxCC) and logarithmic power spectral densities (PSD) averaged in spectral bands of 0.5 Hz width ranging between 0 and 8 Hz. Generalised learn-ing vector quantisation (GRLVQ) was used as ARD method to show the potential of feature reduction. This is compared to support-vector machines (SVM), in which the feature reduction plays a much smaller role. Cross validation yielded mean normalised relevancies of PSD features in the range of 1.6 - 4.9 % and 1.9 - 10.4 % for horizontal and vertical EOG, respectively. MaxCC relevancies were 0.002 - 0.006 % and 0.002 - 0.06 %, respectively. This shows that PSD features of vertical EOG are indispensable, whereas MaxCC can be neglected. Mean classification accuracies were estimated at 86.6±b 1.3 % and 92.3±b 0.2 % for GRLVQ and SVM, respec-tively. GRLVQ permits objective feature reduction by inclu-sion of all processing stages, but is not as accurate as SVM.
Definition, estimation and limitations of the dominant frequency in intracardiac electrograms
Authors: Schwaderlapp Gerald , Oesterlein Tobias , Dössel Olaf , Armin Luik , Schmitt Claus , Lenis Gustavo
Published: September 2017

Intracardiac electrogram recordings during atrial fibrillation (AFib) are characterized by irregular rhythms and complex morphologies. Hence, analysis in the time domain is a difficult task. The so called dominant frequency DF is a spectrum based approach that aims at finding the most relevant frequency in a signal providing information about the rate and dynamics of AFib. However, in recent years various studies reported controversial results regarding the clinical relevance of the DF. In this work, a definition of the DF at a fundamental scale is proposed as the rate at which action potentials are triggered in atrial cells. The most common method to estimate the DF in literature, labeled as DFSpec
, is examined in comparison to the proposed definition. A signal processing study using synthetic signals verified that the DFSpec
is stable for all changes in morphology of atrial activations. However, it is also demonstrated that the DFSpec
becomes unstable for variations above 20% in the cycle length of a signal. Spectrum based DF estimation should be interpreted in a critical manner and is not advisable for study endpoints or clinical markers.