bluuebunny/crossref_metadata_2025 huggingface dataset:
Entre el presente y el pasado, los documentos audiovisuales. Representaciones para la reconstrucción de historia/s reciente/s. Córdoba 1966–1983
Authors: Romano Silvia
Published: December 2016

El tema aquí abordado se inscribe en el proyecto «Pa-trimonio audiovisual, derechos humanos e historiareciente» que, en líneas generales, se propuso contribuiral conocimiento sobre el conjunto de los destinatariosde la represión ilegal y el terrorismo de Estado en ladécada de 1970. La mayor parte de esas personas par-ticipó de la vida política, gremial, estudiantil, barrialde Córdoba en períodos previos a ser desaparecidos yasesinados por lo cual consideramos factible investigaren las noticias televisivas contemporáneas como recursoy fuente histórica para rescatar y restituir sus imágenes,sus voces y reconstruir sus trayectorias en el contextode la época. En ese marco el texto se interroga sobre elmodo en que esos registros audiovisuales contribuyen a que otros sujetos reconstruyan aspectos de ese pasado,sea para producir conocimiento científico o público,interpretaciones audiovisuales, o para elaborar y/ore–elaborar historias personales y grupales, centrandola mirada sobre este último aspecto.
La construcción del sí mismo. El caso de la publicidad electoral: «La fuerza de Atilio» (Frente para la Victoria, 2011)
Authors: Kesler Betina , Jara Valentina
Published: December 2016

La publicidad, en general, visibiliza, pone en superficie e,incluso, construye una necesidad. La publicidad audio-visual, en particular, utiliza estrategias formales del ciney el documental en esta construcción. En este artículo seabordará el modo en que las publicidades electorales dela campaña del Frente para la Victoria (fpv) (2011) creanla necesidad a partir de estrategias formales y, a su vez,a partir de la puesta en funcionamiento de un nosotrospretendidamente inclusivo que configura e instaura un«ser argentino». Sin embargo, en este nosotros puedeleerse el otro término del par dicotómico en tanto eseotro es construido discursivamente por una hegemoníay es tematizado a partir del empleo (formal) de ciertosestereotipos. En este sentido, los spots publicitarios delfpv (2011) operan en la configuración de un nosotrospartidario que supone un lector–consumidor que na-turaliza y reproduce lógicas dominantes.
Sociedad de riesgo: El incumplimiento de la Ley de Acceso a la Información por la Comisión Técnica Nacional de Bioseguridad (ctnBio) de Brasil
Authors: De Oliveira Nildete S.
Published: December 2016

Este artículo hace un análisis sobre la falta de respeto a laLey de Acceso a la Información por la Comisión TécnicaNacional de Bioseguridad (ctnBio). El artículo tambiénreflexiona sobre los riesgos que existen en la sociedad con-temporánea relacionadas con la (ctnBio y el derecho delos ciudadanos y de la sociedad de acceso a la informacióna partir de una perspectiva ambiental. La argumentaciónparte de la comprensión de los conceptos de riesgo, desociedad de riesgo, de derecho a la información y de lanorma creadora de la (ctnBio. Se toma como parámetroun estudio de caso relacionado con el tratamiento dadoa la cuestión de riesgo ambiental y las informacionesproporcionadas por la Comisión Técnica (ctnBio). Seconcluyó que la sociedad, además de tener el derecho,también necesita conocer el grado de riesgo al cual estásiendo expuesta, así como sus consecuencias. Se sugierecomo medida para lograr la solución del problema, la creación inmediata del Sistema de Informaciones enBioseguridad —sib. Esto es para cumplir con la funciónde comunicar datos a la ctnBio que sean de interés paraese órgano y para la población como: sistematizar susinformes anuales con información clara que ayude al ciu-dadano a conocer los temas tratados; promover frecuentesaudiencias públicas con el objetivo de permitir y fomentarel diálogo entre el gobierno y los electores y finalmenteefectivizar el derecho de acceso a la información.
Research Progress in Oncology. Highlighting and Exploiting the Roles of Several Strategic Proteins in Understanding Cancer Biology
Authors: Odiba Arome S. , Ottah Victoria E. , Anunobi Ogechukwu O. , Edeke Affiong A. , Ukegbu Chimere Y. , Chukwunonyelum Ike , Onosakponome Irhuoghene , Joshua Parker E.
Published: December 2016

Although almost all biological processes are mediated by a variety of proteins, it is important to bring to spotlight recent experimental and clinical research advances that had their focus on highlighting and taking advantage of the roles of several strategic proteins in order to gain more understanding of cancer biology. Proteins have a major stake in the initiation, progression, sustenance and completion of cellular processes, and have also demonstrated their vital roles in cancer processes. The characteristic functions of proteins and modified proteins have been utilized in the understanding and treatment of cancer. Recent insights in such roles and applications include linker histone H1.2 in the compaction of chromatin and gene silencing via the recognition of H3K27me3; c-Jun with Fra-2/c-Fos in the promotion of aggressive tumour phenotypes in tongue cancer; the use of sodium channelinhibiting agents targeting the transmembrane protein in breast, colon and prostate cancer; SET-mediated activities; protein interaction networks in glioma; Gpnmb significance as a biomarker; β-carbolines inhibition on Wnt/β-catenin signaling; p53 mutants co-opt chromatin pathways; Bone morphogenetic protein 4 as regulator of the behaviors of cancer cell; Brain-Expressed X-linked (BEX) proteins in human cancers; targeting CDK4/6 including protein kinases to make a reversal of multidrug resistance in sarcoma. In-depth knowledge of Proteomics will go a long way in helping us uncover a lot more strategies that will help us in the long fight against cancer.
Characterization of particle shape, zeta potential, loading efficiency and outdoor stability for chitosan-ricinoleic acid loaded with rotenone
Authors: Feng Bohua , Ashraf Muhammad Aqeel , Peng Liufen
Published: December 2016

Carboxymethyl chitosan grafted with ricinoleic acid (CMC-g-RA), an amphiphilic drug carrier, was synthetized, loaded with rotenone (Rot), and characterized for particles shape, zeta potential, loading efficiency and outdoor stability. Results show that as the ratio of carrier to drug increased, the formulation exhibited monodisperse nanoparticles negative surface charge. The loading efficiency of the formulation was up to 68%. The outdoor test also indicated that the formulation with the higher loading efficiency prevented Rot degradation in natural environments.
Genetic diversity and population structure of ginseng in China based on RAPD analysis
Authors: Wang Shi-jie , Chen Xiao-lin , Han Feng-bo , Li Ru-sheng , Li Gang , Zhao Yan , Xu Yong-hua , Zhang Lian-xue
Published: December 2016

Population genetic diversity was estimated from forty-four individual ginseng (Panax ginsengC.A. Meyer) plants collected from seven geographical populations located in Heilongjiang, Liaoning, and Jilin Provinces of China as well as the People’s Republic of Korea by using randomly amplified polymorphic DNA (RAPD) markers. Overall, 41 polymorphic loci were amplified using ten primer pairs. The polymorphism percentage ranged from 50% to 100% among seven local populations of ginseng, indicating that there is plentiful genetic diversity in wild ginseng populations. The genetic diversity at the species level was higher than that at the population level. Variance analysis showed that there was a significant difference among populations in genetic diversity. The genetic differentiation coefficient (i.e., FST) indicates that 43% of the variation occurred among populations, which indicates that substantial genetic differentiation occurred among populations. At the same time, the measured value of gene flow (Nm) was 0.66 based on the observed genetic differentiation coefficient among populations, suggesting there was moderate gene flow among populations.
Optimizing the extraction of antibacterial compounds from pineapple leaf fiber
Authors: Zhuang Zhikai , Zhang Jin , Li Mingfu , Deng Ganran , Ou Zhongqing , Lian Wenwei , He Junyan , Huang Tao
Published: December 2016

Five different solvents (petroleum ether, chloroform, ethyl acetate, acetone, and distilled water) were used to extract antibacterial compounds from pineapple leaf fiber. Compounds extracted using acetone showed the greatest antibacterial effect against Escherichia coli, measured by inhibition zone diameter. Three extraction parameters including temperature, time and solid-liquid ratio were optimized through orthogonal experiment based on single factor investigations for achieving maximum active substance extraction rate and bacteriostatic effect. Results showed that using acetone, the optimum extraction conditions for temperature, time and solid-liquid ratio were 45°C, 8 h, and 1:40 (g/ml), respectively.
Identification of residual non-biodegradable organic compounds in wastewater effluent after two-stage biochemical treatment
Authors: Xuqing Liu , Yayun Li , Chao Liu , Li Zhang , Hao Yuan , Chao Fu , Ashraf Muhammad Aqeel
Published: December 2016

The main non-biodegradable compounds (soluble microbial product – SMP) of wastewater from the Maotai aromatic factories, located in the Chishui river region, were analyzed by UV spectroscopy, and by solid-phase extraction followed by gas chromatography coupled to mass spectrometry, after a two-stage biochemical treatment. The UV-Vis spectra revealed that the wastewater contained two double-bonds in conjugated systems (conjugated diene or α, β- unsaturated ketone, etc.) and simple non-conjugated chromophores containing n electrons from carbonyl groups or the like. The residual organic non-biodegradable substances were identified using SPE-GC/MS analysis as complex polymers containing hydroxyl, carbonyl, and carboxyl functional groups with multiple connections to either benzene rings or heterocyclic rings. As these compounds are difficult to remove by conventional biochemical treatments, our findings provide a scientific basis for the design of efficient new strategies to remove SMP from wastewater.
In-silico analysis of non-synonymous-SNPs of STEAP2: To provoke the progression of prostate cancer
Authors: Naveed Muhammad , Tehreem Sana , Mubeen Shamsa , Nadeem Fareeha , Zafar Fatima , Irshad Muhammad
Published: December 2016

As a novel biomarker from the STEAP family, STEAP2 encodes six transmembrane epithelial antigens to prostate cancer. The overexpression of STEAP2 is predicted as the second most common cancer in the world that is responsible for male cancer-related deaths. Nonsynonymous SNPs are important group of SNPs which lead to alternations in encoded polypeptides. Changes in the amino acid sequence of gene products can lead to abnormal tissue function. The present study firstly sorted out those SNPs which exist in the coding region of STEAP2 and evaluated their impact through computational tools. Secondly, the three-dimensional structure of STEAP2 was formed through I-TASSER and validated by different software. Genomic data has been retrieved from the 1000 Genome project and Ensembl and subsequently analysed using computational tools. Out of 177 non-synonymous single nucleotide polymorphisms (nsSNPs) within the coding region, 42 mis-sense SNPs have been predicted as deleterious by all analyses. Our research shows a welldesigned computational methodology to inspect the prostate cancer associated nsSNPs. It can be concluded that these nsSNPs can play their role in the up-regulation of STEAP2 which further leads to progression of prostate cancer. It can benefit scientists in the handling of cancerassociated diseases related to STEAP2 through developing novel drug therapies.
microRNAs in cardiovascular disease – clinical application
Authors: Schulte Christian , Karakas Mahir , Zeller Tanja
Published: December 2016

microRNAs (miRNAs) are well-known, powerful regulators of gene expression, and their potential to serve as circulating biomarkers is widely accepted. In cardiovascular disease (CVD), numerous studies have suggested miRNAs as strong circulating biomarkers with high diagnostic as well as prognostic power. In coronary artery disease (CAD) and heart failure (HF), miRNAs have been suggested as reliable biomarkers matching up to established protein-based such as cardiac troponins (cT) or natriuretic peptides. Also, in other CVD entities, miRNAs were identified as surprisingly specific biomarkers – with great potential for clinical applicability, especially in those entities that lack specific protein-based biomarkers such as atrial fibrillation (AF) and acute pulmonary embolism (APE). In this regard, miRNA signatures, comprising a set of miRNAs, yield high sensitivity and specificity. Attempts to utilize miRNAs as therapeutic agents have led to promising results. In this article, we review the clinical applicability of circulating miRNAs in CVD. We are giving an overview of miRNAs as biomarkers in numerous CVD entities to depict the variety of their potential clinical deployment. We illustrate the function of miRNAs by means of single miRNA examples in CVD.
Effects of heat treatment and welding process on superelastic behaviour and microstructure of micro electron beam welded NiTi
Authors: Balz Isabel , Reisgen Uwe , Schoft Julia , Otten Christian
Published: December 2016

Medical devices with small dimensions made of superelastic NiTi become more popular, but joining these parts remains challenging. Since laser welding was found to be an option, electron beam welding seems to be an interesting alternative as it provides additional advantages due to the precise beam positioning and the high vacuum. Superelasticity is influenced by microstructure and surface layer composition that are mainly affected by welding process and by heat treatment and therefore will be investigated in the present paper.
Towards in silico prognosis using big data
Authors: Ohs Nicholas , Keller Fabian , Blank Ole , Lee Yuk-Wai Wayne , Cheng Chun-Yiu Jack , Arbenz Peter , Müller Ralph , Christen Patrik
Published: December 2016

Clinical diagnosis and prognosis usually rely on few or even single measurements despite clinical big data being available. This limits the exploration of complex diseases such as adolescent idiopathic scoliosis (AIS) where the associated low bone mass remains unexplained. Observed low physical activity and increased RANKL/OPG, however, both indicate a mechanobiological cause. To deepen disease understanding, we propose an in silico prognosis approach using clinical big data, i.e. medical images, serum markers, questionnaires and live style data from mobile monitoring devices and explore the role of inadequate physical activity in a first AIS prototype. It employs a cellular automaton (CA) to represent the medical image, micro-finite element analysis to calculate loading, and a Boolean network to integrate the other biomarkers. Medical images of the distal tibia, physical activity scores, and vitamin D and PTH levels were integrated as measured clinically while the time development of bone density and RANKL/OPG was observed. Simulation of an AIS patient with normal physical activity and patient-specific vitamin D and PTH levels showed minor changes in bone density whereas the simulation of the same AIS patient but with reduced physical activity led to low density. Both showed unchanged RANKL/OPG and considerable cortical resorption. We conclude that our integrative in silico approach allows to account for a variety of clinical big data to study complex diseases.
Usability evaluation of a locomotor therapy device considering different strategies
Authors: Langthaler Sonja , Lassnig Alexander , Baumgartner Christian , Schröttner Jörg
Published: December 2016

Usability of medical devices is one of the main determining factors in preventing use errors in treatment and strongly correlates to patient safety and quality of treatment. This thesis demonstrates the usability testing and evaluation of a prototype for locomotor therapy of infants. Therefore, based on the normative requirements of the EN 62366, a concept combined of evaluation procedures and assessing methods was created to enable extensive testing and analysis of the different aspects of usability. On the basis of gathered information weak points were identified and appropriate measures were presented to increase the usability and operating safety of the locomotor prototype. The overall outcome showed an usability value of 77.4% and an evaluation score of 6.99, which can be interpreted as “satisfactory”.
Hypoxia-on-a-chip
Authors: Busek Mathias , Grünzner Stefan , Steege Tobias , Klotzbach Udo , Sonntag Frank
Published: December 2016

In this work a microfluidic cell cultivation device for perfused hypoxia assays as well as a suitable controlling unit are presented. The device features active components like pumps for fluid actuation and valves for fluid direction as well as an oxygenator element to ensure a sufficient oxygen transfer. It consists of several individually structured layers which can be tailored specifically to the intended purpose. Because of its clearness, its mechanical strength and chemical resistance as well as its well-known biocompatibility polycarbonate was chosen to form the fluidic layers by thermal diffusion bonding. Several oxygen sensing spots are integrated into the device and monitored with fluorescence lifetime detection. Furthermore an oxygen regulator module is implemented into the controlling unit which is able to mix different process gases to achieve a controlled oxygenation. First experiments show that oxygenation/deoxygenation of the system is completed within several minutes when pure nitrogen or air is applied to the oxygenator. Lastly the oxygen input by the pneumatically driven micro pump was quantified by measuring the oxygen content before and after the oxygenator.
Bionic forceps for the handling of sensitive tissue
Authors: Kölle Lucia , Schwarz Oliver
Published: December 2016

Anatomical forceps are used for the handling of sensitive structures in medicine. Structures which are manipulated with these forceps can get damaged or slip out of the grip of the forceps. This paper presents a forceps using the bionic Fin-Ray-Effect inspired by fish-fins in order to handle vulnerable structures in particular. During the process of development, functional models of this forceps were designed, 3D-printed and evaluated.
Experimental studies on 3D printing of barium titanate ceramics for medical applications
Authors: Schult Mark , Buckow Eric , Seitz Hermann
Published: December 2016

The present work deals with the 3D printing of porous barium titanate ceramics. Barium titanate is a biocompatible material with piezoelectric properties. Due to insufficient flowability of the starting material for 3D printing, the barium titanate raw material has been modified in three different ways. Firstly, barium titanate powder has been calcined. Secondly, flow additives have been added to the powder. And thirdly, flow additives have been added to the calcined powder. Finally, a polymer has been added to the three materials and specimens have been printed from these three material mixtures. The 3D printed parts were then sintered at 1320°C. The sintering leads to shrinkage which differs between 29.51–71.53% for the tested material mixtures. The porosity of the parts is beneficial for cell growth which is relevant for future medical applications. The results reported in this study demonstrate the possibility to fabricate porous piezoelectric barium titanate parts with a 3D printer that can be used for medical applications. 3D printed porous barium titanate ceramics can especially be used as scaffold for bone tissue engineering, where the bone formation can be promoted by electrical stimulation.
Patient specific root-analogue dental implants – additive manufacturing and finite element analysis
Authors: Gattinger Johannes , Bullemer Christian N. , Harrysson Ola L. A.
Published: December 2016

Aim of this study was to prove the possibility of manufacturing patient specific root analogue two-part (implant and abutment) implants by direct metal laser sintering. The two-part implant design enables covered healing of the implant. Therefore, CT-scans of three patients are used for reverse engineering of the implants, abutments and crowns. Patient specific implants are manufactured and measured concerning dimensional accuracy and surface roughness. Impacts of occlusal forces are simulated via FEA and compared to those of standard implants.
3D printing – a key technology for tailored biomedical cell culture lab ware
Authors: Schmieder Florian , Ströbel Joachim , Rösler Mechthild , Grünzner Stefan , Hohenstein Bernd , Klotzbach Udo , Sonntag Frank
Published: December 2016

Today’s 3D printing technologies offer great possibilities for biomedical researchers to create their own specific laboratory equipment. With respect to the generation of ex vivo vascular perfusion systems this will enable new types of products that will embed complex 3D structures possibly coupled with cell loaded scaffolds closely reflecting the in-vivo environment. Moreover this could lead to microfluidic devices that should be available in small numbers of pieces at moderate prices. Here, we will present first results of such 3D printed cell culture systems made from plastics and show their use for scaffold based applications.
3D printing of hydrogels in a temperature controlled environment with high spatial resolution
Authors: Fischer Benjamin , Schulz André , Gepp Michael M. , Neubauer Julia , Gentile Luca , Zimmermann Heiko
Published: December 2016

There is great hope in 3D printing techniques to create patient specific scaffolds for therapeutic applications. The majority of these approaches rely on materials that both give support to cells and effectively mimic a tissue specific microenvironment. Hydrogels provide an exceptional support for cells but their physicochemical properties are not suited for conventional additive layer manufacturing. Their low viscosity and resulting fluidic nature inhibit voluminous 3D deposition and lead to crude printing accuracy. To enhance mechanical features, hydrogels are often chemically modified and/or mixed with additives; however it is not clear whether these changes induce effects on cellular behavior or if in vivo applications are at risk. Certainly it increases the complexity of scaffold systems. To circumvent these obstacles, we aimed for a 3D printing technique which is capable of creating scaffolds out of unmodified, pure hydrogels. Here we present a new method to produce alginate scaffolds in a viscosity- independent manner with high spatial resolution. This is achieved by printing in a sub-zero environment which leads to fast freezing of the hydrogels, thus preserving the printed shape and circumventing any viscosity dependent flows. This enables the user to create scaffolds which are able to reflect soft or stiff cell niches.
Biocompatibility of photopolymers for additive manufacturing
Authors: Leonhardt Stefan , Klare Martin , Scheer Maurice , Fischer Theresa , Cordes Burghard , Eblenkamp Markus
Published: December 2016

To establish photopolymers for the production of class II or class III medical products by additive manufacturing it is essential to know which components of photopolymeric systems, consisting of monomers, photoinitiators and additives, are the determining factors on their biocompatible properties. In this study the leachable substances of a cured photopolymeric system were eluted and identified by HPLC-MS detection. In addition the cured photopolymer was testes for cytotoxicity and genotoxicity according to DIN EN ISO 10993 for long time applications. The results showed that uncured residual monomers are the determining factor on the biocompatible properties of the photopolymeric system. Strategies to reduce these residual monomers in the cured photopolymer are presented.
Biochemical piezoresistive sensors based on pH- and glucose-sensitive hydrogels for medical applications
Authors: Schmidt Ulrike , Guenther Margarita , Gerlach Gerald
Published: December 2016

Many conventional analysis techniques to detect chemical or biological species are able to achieve a high detection sensitivity, however, they are equipment- or time-expensive due to a multi-step procedure. In this work we describe sensor concepts using piezoresistive pressure sensor chips with integrated analyte-sensitive hydrogels, that enable inexpensive and robust biochemical sensors which are miniaturizable and in-line capable. Biocompatible hydrogels were developed and tested for pH- and glucose-monitoring during the chemical and biochemical processes. For that, monomer mixtures based on hydroxypropyl methacrylate HPMA, 2-(dimethylamino)ethyl methacrylate DMAEMA, tetraethylene glycol dimethacrylate TEGDMA and ethylene glycol EG were photo-polymerized. By means of carbodiimide chemistry, glucose oxidase was bound to the pH-sensitive HPMA/DMAEMA/TEGDMA/EG hydrogel squares causing the glucose-sensitivity. The crosslinked hydrogels were integrated in piezoresistive pressure sensors of different designs. pH- and glucose-depending reversible gel swelling processes were observed by means of the output voltage of dip sensors and of a novel implantable flexible sensor set-up. Due to its biocompatible components, the latter could be used inside the human body monitoring physiological blood values, for example glucose.
Novel wireless measurement system of pressure dedicated to in vivo studies
Authors: Bances Enrique , Fiestas Antonio , Witte Hartmut
Published: December 2016

This paper reports on the development of a wireless system to monitor the thoracic cavity pressure in mammals. This project seeks to open a new field using the radio frequency (RF) technology in the studies of the interaction between breathing and locomotion in mammals. Furthermore, this study embodies the first step to develop a method of telemetry and remote monitoring based on implantable devices. In addition, it can be modified with other sensors to measure different physiological parameters.
Deep brain stimulation: increasing efficiency by alternative waveforms
Authors: Argiti Katerina , Joseph Kevin , Mottaghi Soheil , Feuerstein Thomas J. , Hofmann Ulrich G.
Published: December 2016

Deep brain stimulation (DBS) is based on the effect of high frequency stimulation (HFS) in neuronal tissue. As a therapy option for patients suffering from e.g. Parkinson’s disease, DBS has been used for decades. Despite the widespread use, the effect of HFS on neurons is not fully investigated. Improving the stimulation efficiency und specificity could increase the efficiency of the INS (internal neuronal stimulator) as well as potentially reduce unwanted side effects. The effect of HFS on the GABAergic system was quantified using whole cell patch clamp electrophysiology during HFS stimulation in cortical human brain slicesin vitro. Rectangular, sine, sawtooth and triangular waveforms were applied extracellularly. Since HFS has been hypothesized to increase the activity of the axons of GABAergic interneurons, a decrease in activity can be observed in the pyramidal cells that the interneurons project to. By isolating the incoming non- GABAergic events, we can filter out only the GABAAcurrents which can be verified using a GABAAantagonist. The results show that all the waveforms effectively increase the GABAAcurrents. The triangle waveform causes the highest significant increase in the activity which further increases over time after the stimulation was turned off.
Prediction of immediately occurring microsleep events from brain electric signals
Authors: Golz Martin , Sommer David , Krajewski Jarek
Published: December 2016

This contribution addresses the question if imminent changes of the cortical state are predictable. The analysis is based on 1484 examples of microsleep (MS) and 1940 counterexamples of sustained attention (SA), both observed during overnight driving in the simulator. EEG segments (8 s in length) immediately before each respective event were included. Features were extracted by (i) modified periodogram and (ii) Choi-Williams distribution. Machine learning algorithms, namely the optimized learning vector quantization (OLVQ) and the support-vector machine with Gaussian kernel function (SVM), were trained in order to map signal features to the event type (MS or SA). Cross validation analysis yielded test set classification accuracies of 87.5 ± 0.1 % and 82.7 ± 0.1 % for feature set (i) and (ii), respectively. In general, SVM outperformed OLVQ. In conclusion, EEG contains enough information to predict immediately upcoming microsleep events.
Determining cardiac vagal threshold from short term heart rate complexity
Authors: Hamdan Rami Abou , Schumann Andy , Herbsleb Marco , Schmidt Marcus , Rose Georg , Bär Karl-Jürgen , Gabriel Holger
Published: December 2016

Evaluating individual aerobic exercise capacity is fundamental in sports and exercise medicine but associated with organizational and instrumental effort. Here, we extract an index related to common performance markers, the aerobic and anaerobic thresholds enabling the estimation of exercise capacity from a conventional sports watch supporting beatwise heart rate tracking. Therefore, cardiac vagal threshold (CVT) was determined in 19 male subjects performing an incremental maximum exercise test. CVT varied around the anaerobic threshold AnT with mean deviation of 7.9 ± 17.7 W. A high correspondence of the two thresholds was indicated by Bland-Altman plots with limits of agreement −27.5 W and 43.4 W. Additionally, CVT was strongly correlated AnT (r
p
= 0.86, p < 0.001) and reproduced this marker well (r
c
= 0.81). We conclude, that cardiac vagal threshold derived from compression entropy time course can be useful to assess physical fitness in an uncomplicated way.
Reducing of gradient induced artifacts on the ECG signal during MRI examinations using Wilcoxon filter
Authors: Schmidt Marcus , Krug Johannes W. , Rose Georg
Published: December 2016

The electrocardiogramm (ECG) is the state-of-the-art signal for gating in cardiovascular magnetic resonance imaging and patient monitoring. Using the ECG for gating and monitoring during the magnetic resonance imaging examination is a high challenging task due to the superimposition of the magnetohydrodynamic effect, radio-frequency (RF) pulses and fast switching gradient magnetic fields. The gradient induced artifacts hamper the correct QRS detection which is needed for correct gating and heart rate calculation and ECG displaying for patient monitoring. To suppress the gradient artifacts from the ECG signal acquired during MRI, a technique based on the Wilcoxon filter was developed. It was evaluated using ECG signals of 14 different subjects acquired in a 3 T MRI scanner. It could be shown reliable results for reducing gradient induced artifacts in the ECG signal in real-time.
Automatic detection and mapping of double potentials in intracardiac electrograms
Authors: Oesterlein Tobias , Kramlich Alexander , Lenis Gustavo , Luik Armin , Schmitt Claus , Dössel Olaf
Published: December 2016

Catheter ablation has become a very efficient strategy to terminate sustained cardiac arrhythmias like atrial flutter (AFlut). Identification of the optimal ablation spot, however, often proves difficult when scar from previous ablations is present. Although the application of electro-anatomical mapping systems allows to record thousands of intracardiac electrograms (EGMs) from each atrium, state-of-the-art techniques provide limited options for automatic signal processing. Goal of the presented research was the development of an algorithm to detect EGMs that present double potentials (DPs), as these often indicate functional or anatomical lines of block for cardiac excitation. Using an annotated database, we developed several features based on the morphological descriptors of DPs. These were used to train a binary decision tree which was able to detect DPs with a correct rate of over 90%.
Modeling the pelvic region for non-invasive pelvic intraoperative neuromonitoring
Authors: Moszkowski Tomasz , Krüger Thilo , Kneist Werner , Hoffmann Klaus-Peter
Published: December 2016

Finite element analysis (FEA) of electric current distribution in the pelvis minor may help to assess the usability of non-invasive surface stimulation for continuous pelvic intraoperative neuromonitoring. FEA requires generation of quality volumetric tetrahedral mesh geometry. This study proposes the generation of a suitable mesh based on MRI data. The resulting volumetric mesh models the autonomous nerve structures at risk during total mesorectal excision. The model also contains the bone, cartilage, fat, skin, muscle tissues of the pelvic region, and a set of electrodes for surface stimulation. The model is ready for finite element analysis of the discrete Maxwell’s equations.
Best practice: surgeon driven application in pelvic operations
Authors: Krueger Thilo B. , Wegner Celine , Somerlik-Fuchs Karin H. , Hoffmann Klaus-Peter , Mattmueller Rudi
Published: December 2016

In applied biomedical engineering and medical industry the transfer of established technology towards customers’ needs is essential for successful development and therefore business opportunities. In chronological order, we can show the transfer of scientific results of neurophysiological research into an existing neuromonitoring system and product which can be used by non-experts in medical technology in the operating room environment. All neurophysiology functions were realized in an intuitive graphical user interface. To stimulate the autonomous nerves, a specialized parameter paradigm was used, different from motor nerve stimulation. In the background, a complex signal processing algorithm recorded smooth muscle and bladder manometry data in synchronized time and automatically detected neurophysiological signals. The acquired data was then presented in real-time. With this effort a complex scientific task could be simplified to a Yes/No statement to the end-user. Beside all the reduction of complexity, the scientific challenge was still obtained, as raw-data is still possible to be recorded.
Vasomotor assessment by camera-based photoplethysmography
Authors: Trumpp Alexander , Schell Joachim , Malberg Hagen , Zaunseder Sebastian
Published: December 2016

Camera-based photoplethysmography (cbPPG) is a novel technique that allows the contactless acquisition of cardio-respiratory signals. Previous works on cbPPG most often focused on heart rate extraction. This contribution is directed at the assessment of vasomotor activity by means of cameras. In an experimental study, we show that vasodilation and vasoconstriction both lead to significant changes in cbPPG signals. Our findings underline the potential of cbPPG to monitor vasomotor functions in real-life applications.
Classification of morphologic changes in photoplethysmographic waveforms
Authors: Tigges Timo , Music Zenit , Pielmus Alexandru , Klum Michael , Feldheiser Aarne , Hunsicker Oliver , Orglmeister Reinhold
Published: December 2016

An ever increasing number of research is examining the question to what extent physiological information beyond the blood oxygen saturation could be drawn from the photoplethysmogram. One important approach to elicit that information from the photoplethysmogram is the analysis of its waveform. One prominent example for the value of photoplethysmographic waveform analysis in cardiovascular monitoring that has emerged is hemodynamic compensation assessment in the peri-operative setting or trauma situations, as digital pulse waveform dynamically changes with alterations in vascular tone or pulse wave velocity. In this work, we present an algorithm based on modern machine learning techniques that automatically finds individual digital volume pulses in photoplethysmographic signals and sorts them into one of the pulse classes defined by Dawber et al. We evaluate our approach based on two major datasets – a measurement study that we conducted ourselves as well as data from the PhysioNet MIMIC II database. As the results are satisfying we could demonstrate the capabilities of classification algorithms in the automated assessment of the digital volume pulse waveform measured by photoplethysmographic devices.
Novel computation of pulse transit time from multi-channel PPG signals by wavelet transform
Authors: Pielmuş Alexandru-Gabriel , Pflugradt Maik , Tigges Timo , Klum Michael , Feldheiser Aarne , Hunsicker Oliver , Orglmeister Reinhold
Published: December 2016

Being able to accurately monitor blood pressure in a reliable, truly non-invasive manner is a highly sought after goal within the biomedical community. In this paper we propose and assess a system, methodology and algorithm for unobtrusively obtaining true pulse transit time data from readily accessible peripheral locations, such as the hand, using a highly synchronous body-sensor-network encompassing an electrocardiogram- and dual mode photoplethysmogram sensor node. The results suggest the feasibility of acquiring such data, which strongly correlates with the recorded reference blood pressure, and can therefore be further employed to track changes thereof.
Semi-automated detection of fractional shortening in zebrafish embryo heart videos
Authors: Nasrat Sara , Marcato Daniel , Hirth Sofia , Reischl Markus , Pylatiuk Christian
Published: December 2016

Quantifying cardiac functions in model organisms like embryonic zebrafish is of high importance in small molecule screens for new therapeutic compounds. One relevant cardiac parameter is the fractional shortening (FS). A method for semi-automatic quantification of FS in video recordings of zebrafish embryo hearts is presented. The software provides automated visual information about the end-systolic and end-diastolic stages of the heart by displaying corresponding colored lines into a Motion-mode display. After manually marking the ventricle diameters in frames of end-systolic and end-diastolic stages, the FS is calculated. The software was evaluated by comparing the results of the determination of FS with results obtained from another established method. Correlations of 0.96 < r < 0.99 between the two methods were found indicating that the new software provides comparable results for the determination of the FS.
Blood pressure measurement on the cheek
Authors: Schneider Sarah , Affeld Klaus , Kopic Claudia , Kertzscher Ulrich
Published: December 2016

In a large group of patients, it is impossible to measure blood pressure using an upper arm cuff. An alternative, non-invasive method of blood pressure measurement is required for patients with severe limb deformities or obesity, for amputees, and in the emergency medicine. The device proposed here measures blood pressure in the cheek using a small pressure pad and a pump to occlude the cheek artery – arteria facialis – and assesses blood flow with an infrared light source and a detector. The infrared light signal is analysed to assess the systolic and diastolic blood pressure of the patient. Manual evaluation of the light intensity signal showed a good agreement between cheek blood pressure measurement and a reference measurement using an upper arm cuff.
Derivation of the respiratory rate from directly and indirectly measured respiratory signals using autocorrelation
Authors: Schrumpf Fabian , Sturm Matthias , Bausch Gerold , Fuchs Mirco
Published: December 2016

The estimation of respiratory rates from contineous respiratory signals is commonly done using either fourier transformation or the zero-crossing method. This paper introduces another method which is based on the autocorrelation function of the respiratory signal. The respiratory signals can be measured either directly using a flow sensor or chest strap or indirectly on the basis of the electrocardiogram (ECG). We compare our method against other established methods on the basis of real-world ECG signals and use a respiration-based breathing frequency as a reference. Our method achieved the best agreement between respiration rates derived from directly and indirectly measured respiratory signals.
Real-time QRS detection using integrated variance for ECG gated cardiac MRI
Authors: Schmidt Marcus , Krug Johannes W. , Rose Georg
Published: December 2016

During magnetic resonance imaging (MRI), a patient’s vital signs are required for different purposes. In cardiac MRI (CMR), an electrocardiogram (ECG) of the patient is required for triggering the image acquisition process. However, a reliable QRS detection of an ECG signal acquired inside an MRI scanner is a challenging task due to the magnetohydrodynamic (MHD) effect which interferes with the ECG. The aim of this work was to develop a reliable QRS detector usable inside the MRI which also fulfills the standards for medical devices (IEC 60601-2-27). Therefore, a novel real-time QRS detector based on integrated variance measurements is presented. The algorithm was trained on ANSI/AAMI EC13 test waveforms and was then applied to two databases with 12-lead ECG signals recorded inside and outside an MRI scanner. Reliable results for both databases were achieved for the ECG signals recorded inside (DBMRI: sensitivity Se = 99.94%, positive predictive value +P = 99.84%) and outside (DBInCarT: Se = 99.29%, +P = 99.72%) the MRI. Due to the accurate R-peak detection in real-time this can be used for monitoring and triggering in MRI exams.
Preprocessing of unipolar signals acquired by a novel intracardiac mapping system
Authors: Huck Salina , Oesterlein Tobias , Luik Armin , Schmitt Claus , Wakili Reza , Dössel Olaf
Published: December 2016

The novel high-density mapping system Rhythmia
TM
Medical (Boston Scientific, Marlborough, USA) allows a fast and automatic acquisition of intracardiac electrograms (EGMs). For recording the ORION mini-basket catheter is used. Due to the small electrode surface, the spatial averaging is smaller than with other commonly used mapping catheters. This results in a higher quality of unipolar signals. However, these are still corrupted by noise such as high frequency interference. Within this project, methods were developed and benchmarked that can be applied to detect and remove these undesired components. An algorithm was implemented to detect and eliminate artificial peaks in the spectrum of the EGM. The filtered signals showed improved quality in time domain. The performance of the spectral peak detection resulted in a median sensitivity of 92.1% and in a median positive predictive value of 91.9%.
Continuous non-invasive monitoring of blood pressure in the operating room: a cuffless optical technology at the fingertip
Authors: Solà Josep , Proença Martin , Braun Fabian , Pierrel Nicolas , Degiorgis Yan , Verjus Christophe , Lemay Mathieu , Bertschi Mattia , Schoettker Patrick
Published: December 2016

Routine monitoring of blood pressure during general anaesthesia relies on intermittent measurements with a non-invasive brachial cuff every five minutes. This manuscript provides first experimental evidence that a physiology-based pulse wave analysis algorithm applied to optical data (as provided by a standard fingertip pulse oximeter) is capable of accurately estimating blood pressure changes in-between cuff readings. Combined with the routine use of oscillometric cuffs, the presented novel approach is a candidate technology to increase patient safety by providing beat-to-beat hemodynamic measurements without the need of invasive monitoring procedures.
Application of microwave sensor technology in cardiovascular disease for plaque detection
Authors: Wagner David , Vogt Sebastian , Jamal Farabi Ibne , Guha Subhajit , Wenger Christian , Wessel Jan , Kissinger Dietmar , Pitschmann Kai , Schumann Ulrich , Schmidt Bertram , Detert Markus
Published: December 2016

Arteriosclerosis and associated cardiovascular disease remains the leading cause of mortality. Improved methods for vascular plaque detection allow early diagnose and better therapeutic options. Present diagnostic tools require intense technical expenditure and diminish value of modern screening methods. Our group developed an microwave sensor for on-site detection of plaque formation in arterial vessels. The sensor is an oscillator working around 27 GHz which is coupled to a microstrip stub line. The final flexible polyimid interposer has a length of 38 cm, a width of 1.2 mm and a thickness of 200 μm. Because of its minimal size the interposer completed a catheter with a diameter of 8F ready for further clinical use in cardiology and heart surgery.
Artificial blood circulatory and special Ultrasound Doppler probes for detecting and sizing gaseous embolism
Authors: Stark Philipp , Kalkbrenner Christoph , Braß Patrick , Brucher Rainer
Published: December 2016

This paper presents a special designed artificial blood circulatory (ABC) for studying gaseous embolism based on detection of gaseous emboli and their sizing using ultrasound (US) spectral Doppler. Blood mimicking fluid (BMF) was used in the circulatory to get valid results without using human blood. The additional necessary degassing circulatory shows a promising effect of decontaminating the BMF from air bubbles. This offers the base for detecting and sizing microemboli using special algorithms and finally leads to reliable calculations of dangerous embolism and its air volume. Standard US probes at an integrated tissue model and a new 8-MHz central catheter ultrasound (CCUS) probe inside a superior vena cava model (SVCM) are used and deliver the Doppler spectrogram as input for automatic emboli detection and further signal analysis. First results using the newly developed 8-MHz CCUS probe inside the SVCM and its Doppler spectrogram characteristics show promising results but need more detailed studies.
A method to determine the kink resistance of stents and stent delivery systems according to international standards
Authors: Brandt-Wunderlich Christoph , Schwerdt Christopher , Behrens Peter , Grabow Niels , Schmitz Klaus-Peter , Schmidt Wolfram
Published: December 2016

The kink behavior of vascular stents is of particular interest for clinicians, stent manufacturers and regulatory as a kinked stent generates a lumen loss in the stented vessel and can lead to in-stent restenosis. In this study methods to determine the kink resistance of stents and stent delivery systems according to the ISO 25539-2 and FDA guidance no. 1545 were presented. The methods are applicable for balloon expandable stents as well as for self-expanding stents and determine the lumen loss and residual diameter change dependent on the specific bending radius.
Comparison of stented bifurcation and straight vessel 3D-simulation with a prior simulated velocity profile inlet
Authors: Wüstenhagen Carolin , Borowski Finja , Grabow Niels , Schmitz Klaus-Peter , Stiehm Michael
Published: December 2016

Coronary diseases are the main reason for death in the western world. Bio-fluid mechanical correlations with arterial diseases are in the focus of our research. To treat occluded vessels, stents are implanted. Stent implantations can be associated with blood flow disruptions leading to restenosis or thrombosis formation. Numerical flow simulation is a promising tool to evaluate the hemodynamic performance of cardiovascular implants, but is resource-intensive in time and computational power. Therefore, a reduction in grid size would be beneficial due to economic exploitation of computational cost. The purpose of this numerical investigation is to substitute the computational domain of a distal stented bifurcation with a stented straight vessel by using the right inlet condition. The deviation of the results of the two different methods to simulate the blood flow situation in a bifurcation is marginal. This inlet can be used for standardised simulations of bifurcations were lesions commonly occur.
Transient Euler-Lagrange/DEM simulation of stent thrombosis
Authors: Stiehm Michael , Wüstenhagen Carolin , Grabow Niels , Schmitz Klaus-Peter
Published: December 2016

Stent implantation is the treatment of choice for cardiovascular diseases. By introduction of biodegradable thick strut stents investigations of thrombosis formation is one focus of research. This study deals with a transient Euler-Lagrange/DEM approach to simulate the flow field, platelet movement and clotting. The recirculation zones prolong particle residence time. As a result, the vicinity of stent struts shown a particularly higher risk for stent thrombosis.