bluuebunny/crossref_metadata_2025 huggingface dataset:
Usage and Impact of Information and Communication Technologies in Healthcare Delivery
Authors: Kong Lu , Sadatsafavi Hessam , Verma Rohit
Published: September 2019

This paper discusses two aspects of the use of information and communication technologies (ICTs) in healthcare: first, the prevalence of using tables and laptop computers by physicians during clinical visits and second, the growing trend of using such technologies for delivering healthcare remotely. Open-ended and structured questionnaires were used to elicit relevant information, which was analyzed using qualitative content analysis and logistic regression models. Results suggest that, as computer literacy is increasing within the general population and caregivers’ skills in using the computer technology is improving, patients are welcoming the use of ICTs in healthcare. The analysis also showed that age together with enabling factors, such as income and education, are substantial barriers to the use of remote care services, even more important than gender, place of residence, race or ethnicity, and care need. Income and education do not influence the acceptance of ICT use by doctors during visits. Females, older participants, and those with more children in the household showed more resistance to the use of ICT in healthcare. At the same time, the depersonalization of interactions with caregivers was a critical concern identified related to the use of ICT in healthcare.
Learning from the past, looking to the future
Authors: Maclean Gaynor D
Published: September 2019

This article offers an insight into past achievements in moving towards safe motherhood. Considering data from across the globe and in particular achievements in Africa, lessons that have been learned are shared and present a fitting focus for the years ahead. Co-operation, competence, compassion and commitment are the ‘four Cs’ of 21st century midwifery, and offer direction, inspiration and purpose. Promoting safer childbirth for women everywhere, especially the most vulnerable, is a shared goal in midwifery, and moving forward together with optimal skills and attitudes will enable midwives to make a real difference where it matters most.
Batwing mammoplasty: a safe oncoplastic technique for breast conservation in breast cancer patients with gigantomastia
Authors: Manie TM , Youssef MMG , Taha SN , Rabea A , Farahat AM
Published: September 2019

Background

Surgical management of breast cancer with gigantomastia can be challenging when planning breast conservation, as major breast reduction is required. Complex oncoplastic procedures can carry an additional surgical risk in this situation. We suggest batwing mammoplasty as a simple and safe oncoplastic procedure for those patients.

Materials and methods

Fourteen patients with gigantomastia diagnosed with breast cancer were included in this prospective cohort study. All underwent batwing mammoplasty and contralateral symmetrisation procedure between May 2016 and June 2018. Patient satisfaction assessed by the Breast-Q questionnaire.

Results

All patients had a body mass index above 30kg/m2 with a mean of 36.7kg/m2 (range 31.6–44.9kg/m2). The mean distance from midclavicular point to nipple was 42cm (range 38–50cm). The mean operative time was 83 minutes for procedures done by a single surgeon. Mean specimen weight was 1.2kg (ranging from 1.035–1.63kg). Postoperative complications occurred in 14.2% of patients. Nipple–areola complex viability was not compromised nor sensation impaired. The mean Breast-Q score for patient satisfaction with breasts was 68.6 (range 61–74). The mean score for physiological wellbeing was 77.3 (range 64–84) and the mean score for physical wellbeing was 35 (range 31–40).

Conclusion

Batwing mammoplasty is a safe and simple oncoplastic procedure in patients who have breast cancer with gigantomastia. It has short operative time and low complications rate. In our cohort of patients, there was no delay in the delivery of adjuvant treatment. The cosmetic outcome was favourable with a high patient satisfaction.
Framed to fit? Challenging the domestic abuse ‘story’ in child protection
Authors: Ferguson Greig , Featherstone Brid , Morris Kate
Published: September 2019

The current framing of domestic violence generates profound problems for those concerned with supporting change for all involved. In particular, the stress on the ‘equal vulnerability’ of all women to domestic abuse, irrespective of economic or social circumstances, is out of line with a developing evidence base and deprives policymakers and practitioners of the conceptual tools that are needed to situate actual identities, choices and challenges with differing implications for women as well as men. In this article, we note the relative lack of attention in the UK to the work of international researchers on how gendered inequalities intersect with those arising from a range of others, crucially, class and ‘race’. This body of work also draws attention to the importance of understanding the impact of state interventions on marginalised communities, an area also neglected in the UK.
The promise and agony of migration: Formation of identity across memory as a voyage and distance as exile
Authors: Al-Kurdi Wasim
Published: September 2019

In the last decade, death boats in the Mediterranean have stolen the lives of thousands of people escaping wars in Iraq, Syria and Gaza. Immigration in Palestine started in the twentieth century with young people escaping to Western countries to dodge forced military service imposed by the Ottoman Empire during World War II, while tens of thousands of Palestinians found themselves forced to leave their cities and villages to dwell in refugee camps still exist today. I worked on a drama with students and teachers that arose from this complex and multifaceted historical context. It is a subject that influences and is influenced by people’s lives. Travelling between different geographies has changed our perception of identity through deconstructing and re-examining it. In light of this, the drama on which I worked was able to explore the concepts of place, distance and the ‘other’ in relation to people’s fate. We explored the meaning of identity as a ‘cultural and historical definition of the individual or group of people’ and as an individual’s identification card (passport), then looked at the relationship between them.
When tragedy embraces the farce: Adaption of Gogol’s The Government Inspector in different cultures
Authors: Meyer Wendy Lathrop
Published: September 2019

How do drama and theatre contribute to developing a democratic process at the intersection between production, activity and way of working? This article examines how artistic processes can shed light on, investigate and comment about moral dilemmas based on Nicolai Gogol’s dramatic script from 1836, The Government Inspector, a Russian farce about corruption. A Nordplus-project designed in 2013 made it possible for drama students, both in Norway and in Tanzania, to establish platforms enabling the students from each country to freely investigate and interpret their own ideas of corruption through process drama activity by exploring Gogol’s original text. This article also investigates whether and how the students’ cultural identity affected their own perspectives on the matter by pinpointing the aftermath of corrupt activity through dramatic depiction and activity.
Working in multiple figured worlds and positionings to reinvestigate the science behind a national tragedy
Authors: Swanson Carrie
Published: September 2019

This article outlines research that intersects the fields of drama and science education. It highlights the value of using positioning theory and figured worlds to illuminate how the concept of Mantle of the Expert supports science learning. Drama has been found to enhance engagement and learning in science, but its use is uncommon. This article reports on a mixed-methods action research project that examined whether Mantle of the Expert supported or constrained the learning of science with 29 New Zealand students in Years 7 and 8. Data generated from students pre- and post-unit assessments, observations of classroom episodes, student and teacher interviews, and classroom artefacts were analysed statistically and thematically. The positioning triad of position, storyline and speech acts was used to show how the different components of Mantle of the Expert supported science learning. Examining the different figured worlds within which the students operated illuminated the different affordances of each learning space. In addition, the data showed that the students improved significantly in their conceptual understanding of the science taught and provided an opportunity to work within an expert scientist role.
Lactancia materna, alimentación complementaria y suplementación con multimicronutrientes: Perspectiva intercultural
Authors: Bustamante Llatas Jessica Paola , Gordillo Julón Miguel Amberly , Díaz Manchay Rosa Jeuna , Mogollón Torres Flor de María , Vega Ramírez Angelica Soledad , Tejada Muñoz Sonia
Published: September 2019

Introducción: La alimentación en el niño es fundamental para su adecuado crecimiento y desarrollo saludable; sin embargo algunas prácticas culturales arraigadas en diferentes comunidades han influido en la morbilidad y la mortalidad infantil, a pesar de la educación sanitaria que brinda el personal de salud.Objetivo: Describir y comprender la lactancia materna, alimentación complementaria y suplementación con multimicronutrientes al lactante menor desde una perspectiva intercultural.Métodos: Estudio cualitativo, con diseño etnográfico. La muestra estuvo conformada 25 participantes (10 enfermeros y 15 madres andinas), elegidas por conveniencia y determinada por la técnica de saturación y redundancia. Para la recolección de datos se usó la entrevista etnográfica y la observación participante, registrándose en el diario de campo, procesados mediante análisis temático. Se tuvo en cuenta los criterios de rigor científico y los principios de bioética personalista.Resultados: Emergieron tres temas culturales: A) Educación sanitaria, costumbres y lactancia materna. B) Educación sanitaria y prácticas culturales en la alimentación complementaria. C) Educación sanitaria, consumo y rechazo de multimicronutrientes. Conclusiones: El personal de salud educa a la madre andina acerca de  una adecuada alimentación que deben realizar en el hogar, pero más prevalece sus costumbres y creencias, lo que puede ocasionar deficiente crecimiento y desarrollo.
Perfil epidemiológico de casos de sífilis em gestantes em uma maternidade pública
Authors: Da Silva Deusiane Pereira , Cunha Karla Joelma Bezerra , Lages Camila Marinho , Albuquerque Ana Carolina Dias , Dos Santos Vagner Ferreira , Pereira Lívia Carvalho
Published: September 2019

Objetivo: O objetivo do estudo foi analisar operfil epidemiológico dos casos de sífilisem gestante em uma maternidade deTeresina, Piauí, em 2016. Método: Pesquisa epidemiológica descritiva e documental, com abordagem quantitativa, realizado no Serviço de Vigilância Epidemiológica da referida maternidade, de novembro de 2016 a janeiro de 2017, a partir de dados do Sistema de informação de Agravos de Notificação (SINANNET). Os dados foram estratificados segundo: faixa etária, escolaridade, idade gestacional no diagnóstico, titulação do teste não treponêmico, a classificação da sífilis e adesão do parceiro. Resultados e discussão: Em relação a prevalência, no ano de 2016 foram notificados setenta e cinco casos, que corresponde a 2,8%. A doença mostrou-se prevalente nas mulheres na faixa etária de 20 a 29 anos e que cursaram ensino fundamental incompleto. A maioria (77,33%) foi diagnosticada no terceiro trimestre, 22,7% das gestantes apresentaram VRDL de 1:16, a classificação clinica mais incidente foi a terciária e latente com 61,33% dos casos, com relação à adesão dos parceiros, somente 32% realizaram tratamento. Conclusões: É necessário um diagnóstico, tratamento e seguimento rigorosos na tentativa de reduzir os casos de sífilis em gestantes e sífilis congênita, assim como romper a cadeia de transmissão com estratégias e ações direcionadas no combate à doença.
LAND-SOIL CHARACTERISTICS FOR MAPPING PADDY CROPPING INTENSITY USING DECISION TREE ANALYSIS FROM SINGLE DATE ALI IMAGERY IN MAGELANG, CENTRAL JAVA, INDONESIA
Authors: Arjasakusuma Sanjiwana , Danoedoro Projo , Herumurti Sigit , Nugroho Yanuar Adji , Aryaguna Prama Ardha
Published: September 2019

Paddy field area and its cropping intensity are main information used to measure the crop production and the response of crop to changing climate conditions. Remote sensing technology has been used widely to map cropping pattern of paddy mostly using spectral analysis of multi temporal multispectral data of remote sensing. However, the cropping intensity of paddy was also influenced by the characteristics of planted land to paddy field which defines the level of land suitability for planting paddy.  This research aimed to map paddy rotation by using single date ALI imagery by assessing the land and soil characteristics based on the land suitability parameters for planting paddy.  Soil characteristics such as texture, acidity level, P205 (phosphor) and C-organic level collected from field work and terrain characteristics such as landform, surface water, and drainage density from visual delineation of SRTM 90 m was collected as inputs for the decision tree analysis to map the repetition of paddy planting throughout the year. The results showed the overall accuracy of 85% ± 8% (95 % level of confidence) for the final paddy rotation map where 2-times paddy per year was mostly found in the study area.
Unusual accessory peroneal muscles, peroneus quartus, peroneus digiti quinti, and their association with peroneus brevis tendon tear
Authors: Dangintawat Pimpimol , Apinun Jirun , Huanmanop Thanasil , Agthong Sithiporn , Akkarawanit Prim , Chentanez Vilai
Published: September 2019

Background

Anatomic variation and supernumerary contents in the superior peroneal tunnel, and the prominence of the retrotrochlear eminence and peroneal tubercle are related to peroneal tendon disorders.

Objectives

To investigate the prevalence, origin, and insertion of accessory peroneal muscles, the prominence of the retrotrochlear eminence and peroneal tubercle, and their association with peroneal tendon tears.

Methods

We examined 109 formalin-embalmed legs of cadavers from Thai donors. Accessory peroneal muscles and peroneal tendon tears were noted. Associations with peroneal tendon tears were evaluated using a χ2 test.

Results

We found 48 accessory peroneal muscles comprising 13 peroneus quartus (PQ), 33 peroneus digiti quinti (PDQ), and 2 unusual muscles. All PDQ originated from the PB tendon and inserted on various parts of the 5th toe. The PQ originated mostly from the PB muscle belly and less from the tendinous part with various insertions on the retrotrochlear eminence, peroneal tubercle, cuboid, and dorsolateral surface of the 5th metatarsal base. Two unusual accessory muscles were identified, 1 coexisting with the PQ. A PB tendon tear was found in 13% of specimens. We found no association between the peroneal tendon tears and the accessory peroneal muscles, or prominence of the retrotrochlear eminence or peroneal tubercle.

Conclusions

The prevalence of PQ, PDQ, and unusual accessory peroneal muscles was concordant with previous findings. We noted a new type of unusual accessory peroneal muscle coexisting with the PQ. No association was found between peroneal tendon tears and the PQ, PDQ, or prominence of the retrotrochlear eminence or peroneal tubercle.
A maximum principle for circle-valued temperatures
Authors: Cooper Andrew A.
Published: September 2019

In this note we prove a ‘maximum principle’ for circle-valued solutions of the (time-dependent) heat equation on closed Riemannian manifolds.
Practical approach to method verification in plasma and validation in cerebrospinal fluid under accreditation using a flexible scope in molecular virology: setting up the HIV, HBV and HCV Aptima™ Quant Dx assays
Authors: Lefeuvre Caroline , Pivert Adeline , Tran Cong T. , Lunel-Fabiani Françoise , Ducancelle Alexandra , Le Guillou-Guillemette Hélène
Published: September 2019

Background

Our laboratory obtained the ISO 15189 accreditation for the plasmatic HIV-1, HBV and HCV viral load (VL) using the m2000 RealTime™ system, which was recently changed for the platform Panther®. Here, we discuss a strategy for performing method validation/verification very quickly.

Methods

We performed the mandatory (repeatability, internal quality assessment [IQA], measurement uncertainty [MU]) and optional technical verifications for CE/IVD assays using the flexible scope range A. We also performed the mandatory assays for the validation of HIV-1 VL in the cerebrospinal fluid (CSF) using the flexible scope range B. The change was checked by following up on the turnaround time (TAT).

Results

The coefficient of variation (CV%) for repeatability and IQA complied with the limit of 0.25 log. The MU results ranged from 0.04 to 0.25 log copies or IU/mL. The comparisons of methods showed excellent correlations (R2 = 0.96 for the three parameters) but a delayed centrifugation on HCV VL showed variations of up to 2 log IU/mL. An excellent linearity for HIV-1 in the CSF was obtained from 1.5 to 5 log copies/mL with R2 = 0.99. The TAT increased (84%–98%) in routine usage.

Conclusions

The three Aptima assays are well suited for routine laboratory use and can be integrated within less than 2 weeks in accordance with flexible scope range A. Our data allows us to confidently perform HIV-1 VL in CSF following flexible scope range B. Finally, we provide an organizational guide for flexible scope management in molecular virology within a short time frame.
Pre-, post- or no acidification of urine samples for calcium analysis: does it matter?
Authors: Chenevier-Gobeaux Camille , Rogier Marie , Dridi-Brahimi Imane , Koumakis Eugénie , Cormier Catherine , Borderie Didier
Published: September 2019

Background

Measuring 24 h-urine calcium concentration is essential to evaluate calcium metabolism and excretion. Manufacturers recommend acidifying the urine before a measurement to ensure calcium solubility, but the literature offers controversial information on this pre-analytical treatment. The objectives of the study were (1) to compare pre-acidification (during urine collection) versus post-acidification (in the laboratory), and (2) to evaluate the impact of acidification on urinary calcium measurements in a large cohort.

Methods

We evaluated the effects of pre- and post-acidification on 24-h urine samples collected from 10 healthy volunteers. We further studied the impact of acidification on the calcium results for 567 urine samples from routine laboratory practice, including 46 hypercalciuria (≥7.5 mmol/24 h) samples.

Results

Calciuria values in healthy volunteers ranged from 0.6 to 12.5 mmol/24 h, and no statistical significance was found between non-acidified, pre-acidified and post-acidified conditions. A comparison of the values (ranging from 0.21 to 29.32 mmol/L) for 567 urine samples before and after acidification indicated 25 samples (4.4%) with analytical differences outside limits of acceptance. The bias observed for these deviant values ranged from −3.07 to 1.32 mmol/L; no patient was re-classified as hypercalciuric after acidification, and three patients with hypercalciuria were classified as normocalciuric after acidification. These three deviant patients represent 6.5% of hypercalciuric patients.

Conclusions

Our results indicate that pre- and post-acidification of urine is not necessary prior to routine calcium analysis.
DOAC-Remove abolishes the effect of direct oral anticoagulants on activated protein C resistance testing in real-life venous thromboembolism patients
Authors: Kopytek Magdalena , Ząbczyk Michał , Malinowski Krzysztof P. , Undas Anetta , Natorska Joanna
Published: September 2019

Background

Direct oral anticoagulants (DOACs) may cause false results of activated protein C resistance (APC-R) ratio. DOAC-Remove, a new reagent based on activated carbon, has been designed to eliminate the interference of DOACs on coagulation assays. The aim of the study was to investigate whether the use of DOAC-Remove enables to determine APC-R in patients treated with DOACs.

Methods

We assessed 74 venous thromboembolism (VTE) patients, including 25 on rivaroxaban, 25 on apixaban and 24 taking dabigatran. APC-R was determined using the Russell Viper Venom Time (RVVT)-based clotting test. APC-R and DOAC concentrations were tested at baseline and following DOAC-Remove. Thrombophilia, including factor V Leiden (FVL) mutation was tested.

Results

FVL mutation was found in 20 (27%) patients. The APC-R ratio at baseline was measurable in 43 patients (58.1%), including 20 (80%) on rivaroxaban, 19 (76%) on apixaban and four (16.7%) on dabigatran. In patients with measurable APC-R at baseline, the ratio >2.9 was found in 23 patients (53.5%). In 16 (37.2%) subjects APC-R ratio <1.8 suggested FVL mutation which was genetically confirmed. Four (9.3%) FVL carriers on dabigatran showed negative/equivocal APC-R results. In 11 (14.9%) patients taking rivaroxaban or apixaban, in whom blood was collected 2–5 h since the last dose, we observed unmeasurable APC-R. DOAC-Remove almost completely eliminated all plasma DOACs. After addition of DOAC-Remove all APC-R ratios were measurable. In four FVL carriers on dabigatran with false negative APC-R, DOAC-Remove resulted in APC-R ratios <1.8.

Conclusions

DOAC-Remove effectively reduces DOACs concentration in plasma, which enables FVL testing using APC-R.
Inter-individual variability of EEG features during microsleep events
Authors: Golz Martin , Schenka Adolf , Haselbeck Florian , Pauli Martin Patrick
Published: September 2019

This paper examines the question of how strongly the spectral properties of the EEG during microsleep differ between individuals. For this purpose, 3859 microsleep examples were compared with 4044 counterexamples in which drivers were very drowsy but were able to perform the driving task. Two types of signal features were compared: logarithmic power spectral densities and entropy measures of wavelets coefficient series. Discriminant analyses were performed with the following machine learning methods: support-vector machines, gradient boosting, learning vector quantization. To the best of our knowledge, this is the first time that results of the leave-one-subject-out cross-validation (LOSO CV) for the detection of microsleep are presented. Error rates lower than 5.0 % resulted in 17 subjects and lower than 13 % in another 11 subjects. In 3 individuals, EEG features could not be explained by the pool of EEG features of all other individuals; for them, detection errors were 15.1 %, 17.1 %, and 27.0 %. In comparison, cross validation by means of repeated random subsampling, in which individuality is not considered, yielded mean error rates of 5.0 ± 0.5 %. A subsequent inspection of raw EEG data showed that in two individuals a bad signal quality due to poor electrode attachment could be the cause and in one individual a very unusual behavior, a high and long-lasting eyelid activity which interfered the recorded EEG in all channels.
Relationship between core body temperature and heart rate variability in an ultrashort sleep-wake schedule
Authors: Heinze Christian , Golz Martin
Published: September 2019

The circadian rhythm that drives the human sleepwake cycle manifests itself in the variation of the core body temperature (CBT). Measuring CBT continuously, however, is intricate. Heart rate and its variability also varies notably over the course of the day, but is more accessible to measure. We present first results from a study that investigates the biorhythmic relationship between the circadian rhythm of CBT and measures of heart rate variability (HRV). Twelve subjects participated in a 50-hour experiment that was segmented into one hundred 30-minute blocks. In each block, subjects attempted to sleep for ten minutes. CBT and the ECG were continuously recorded. To date, intervals between successive heart beats (RR intervals) were determined for three subjects. From RR intervals of each attempted-sleep episode, power spectral densities (PSD) were estimated with the Lomb-Scargle periodogram and averaged into 0.02-Hz wide bands. The periodogram of each RR-frequency-band time series was estimated and compared against the periodogram of CBT, which, as expected, shows a dominant maximum at a period length of 24 hours. Mutual information, an entropy-based measure of interdependence, was used for the comparison. The highest coherence towards CBT was found for the RR-PSD between 0.24 and 0.34 Hz. This RR-PSD range usually includes the respiratory rate, which may indicate that heart rate is more closely linked to respiration at certain times of the day than at others.
Heart Rate Variability Analysis During Lower Body Negative Pressure Test Induced Central Hypovolemia
Authors: Tigges Timo , Bajrami Lorik , Pielmuş Alexandru-Gabriel , Klum Michael , Orglmeister Reinhold , Wiegank Ludwig , Feldheiser Aarne
Published: September 2019

In clinical patient monitoring scenarios, the detection of hemorrhage is still a major problem. Traditional vital signs like heart rate and blood pressure are insensitive to blood loss due to compensatory mechanisms in the body that can sustain these parameters until shortly before cardiovascular collapse. These compensatory mechanisms during blood loss are primarily driven by the autonomic nervous system. Heart rate variability analysis is a viable tool in the quantitative analysis of the autonomic nervous system and shows promising results in the context of hypovolemia detection. In order to investigate if HRV parameters suitably reflect a mild to moderate blood volume reduction, we conducted a lower body negative pressure test study with 30 volunteering participants thereby simulating progressive central hypovolemia. Here, HRV parameters from the time domain (mean HR, SDNN, RMSSD, rSDRM, pNN50), the frequency domain (VLF, LF, HF, LF/HF), non-linear HRV parameters (SD1, SD2, SD1/SD2, SampEn, ApEn) and the respiratory rate (RR) were collected. The changes of the evaluated parameters as a consequence of the reduced blood volume were statistically evaluated. A statistically significant deviation from their baseline values could be found for RMSSD, rSDRM, pNN50, HF, LF/HF, SD1 and SD1/SD2 at a chamber pressures starting at −30 mmHg. Therefore, we support the proposition that heart rate variability analysis can help in detecting otherwise occult hypovolemia.
MRV-validated numerical flow analysis of thrombotic potential of coronary stent designs
Authors: Oldenburg Jan , Borowski Finja , Schmitz Klaus-Peter , Stiehm Michael , Öner Alper Ö , Quirin Lukas , John Kristine , Bruschewski Martin , Grundmann Sven
Published: September 2019

The formation of a thrombus is associated with dramatic consequences for the patient, such as increased risks of neurologic events and myocardial infarction or even death. A pathologically altered blood flow is associated with these complications. Consequently, a consistent fluid-mechanical analysis of implants, such as coronary stents, must be carried out. Computational fluid dynamics (CFD) is an important in silico tool for the analysis of different stent designs. Using three different generic stent designs (closed-cell, open-cell and helical), CFD could be performed with the OpenFOAM software package. The stents were implemented in a vascular model having a fully developed Hagen-Poiseuille velocity profile (umean = 0.6 m/s) as inlet condition. In combination with the dynamic viscosity of the Newtonian test fluid of 6.04·10-5m2/s, Reynolds numbers up to 460 were achieved. Spatially high-resolved velocity fields from measurements in the magnetic resonance tomograph (magnetic resonance velocimetry, MRV) were available for validation. The velocity field was compared in selected cross sections and longitudinal sections. The difference of the main flow proximal and distal to the stent models were below 6 %. In addition, a similar flow topology could be quantified using the Q-criterion. Due to the very good agreement of the numerical results with the MRV-measurements, the numerical method has been applied to further analysis of stent designs regarding to time average wall shear stress (TAWSS) distribution on the luminal vessel surface (surface area with TAWSS < 0.4 Pa was related to overall vessel surface) under pulsatile conditions. Although all stent designs have the same square cross-section, a large influence of the stent design on WSS distribution could be observed (closedcell vs. helical = -50.2 %; open-cell vs. helical = -38.5 %). By using validated CFD it was possible to quantify the hemodynamic benefit of helical stent design in terms of thrombosis potential.
Esophageal electrode model and simulation of directed transesophageal electrical pacing of the spinal cord
Authors: Schleh Manuela , Heinke Matthias , Hörth Johannes
Published: September 2019

Spinal cord stimulation (SCS) is the most commonly used technique of neurostimulation. It involves the stimulation of the spinal cord and is therefore used to treat chronic pain. The existing esophageal catheters are used for temperature monitoring during an electrophysiology study with ablation and transesophageal echocardiography. The aim of the study was to model the spine and new esophageal electrodes for the transesophageal electrical pacing of the spinal cord, and to integrate them in the Offenburg heart rhythm model for the static and dynamic simulation of transesophageal neurostimulation. The modeling and simulation were both performed with the electromagnetic and thermal simulation software CST (Computer Simulation Technology, Darmstadt). Two new esophageal catheters were modelled as well as a thoracic spine based on the dimensions of a human skeleton. The simulation of directed transesophageal neurostimulation is performed using the esophageal balloon catheter with an electric pacing potential of 5 V and a trapezoidal signal. A potential of 4.33 V can be measured directly at the electrode, 3.71 V in the myocardium at a depth of 2 mm, 2.68 V in the thoracic vertebra at a depth of 10 mm, 2.1 V in the thoracic vertebra at a depth of 50 mm and 2.09 V in the spinal cord at a depth of 70 mm. The relation between the voltage delivered to the electrodes and the voltage applied to the spinal cord is linear. Virtual heart rhythm and catheter models as well as the simulation of electrical pacing fields and electrical sensing fields allow the static and dynamic simulation of directed transesophageal electrical pacing of the spinal cord. The 3D simulation of the electrical sensing and pacing fields may be used to optimize transesophageal neurostimulation.
Correlation-based spike sorting of multivariate data
Authors: Larionov Pavel , Juergens Tom , Schanze Thomas
Published: September 2019

Automated classification of waveforms is an important method of data processing used in various fields of science, such as neuroscience, biomedical engineering, etc. This work shows the possibility of sorting special waveforms i.e. spikes recorded with multichannel electrode arrays by using principles of correlation and data-driven reference. A new method to estimate the number of k-means clusters by using a Monte Carlo method is introduced. To demonstrate the performance of the algorithm, generated signals were used, which are created to mimic multichannel recording of the extra-cellular neuronal signals.
Learning by Researching – Students enhance perfusionist’s workplace with data glasses in internships
Authors: Pawelzik Leonard , Ibenthal Elisabeth , Backhaus Claus
Published: September 2019

A new internship for the module human factors engineering of the study course biomedical engineering was developed on the concept of learning by researching combining the transfer of knowledge with gathering new and publishable findings. Students pass the research cycle, investigating whether perfusionists strain can be reduced by utilizing data glasses. Corresponding to the concept of cooperative learning, students (n = 40) are divided into teams of five, giving each member a predefined expert role. Each expert is responsible either for physiological measurements, the perfusionists workspace, planning of usability tests, data glasses applications or team leading. Following the research cycle, milestones are set at which the teams present partial results to the entire group. Initially, students immerse in the field of research by reviewing literature. They prepare and present research hypotheses and select one for their investigation. Proximately, each team develops and introduces their research design. Teams organize themselves with planning test days and inviting subjects (n ≥ 10 each team). Finally, results are presented in group and collated by each team in a scientific paper. Every team reviews a scientific paper from another team and returns it before they are send in for grading. Evaluation shows higher workloads for students, but also relevant and interesting input. Two groups publish their papers in scientific journals.
An actuated larynx phantom for pre-clinical evaluation of droplet-based reflex-stimulating laryngoscopes
Authors: Friedemann Fast Jacob , He Jiazhen , Ortmaier Tobias , Jungheim Michael , Ptok Martin , Kahrs Lüder Alexander
Published: September 2019

The laryngeal adductor reflex (LAR) is an important protective function of the larynx to prevent aspiration and potentially fatal aspiration pneumonia by rapidly closing the glottis. Recently, a novel method for targeted stimulation and evaluation of the LAR has been proposed to enable non-invasive and reproducible LAR performance grading and to extend the understanding of this reflexive mechanism. The method relies on the laryngoscopically controlled application of accelerated water droplets in association with a high-speed camera system for LAR stimulation site and reflex onset latency identification. Prototype laryngoscopes destined for this method require validation prior to extensive clinical trials. Furthermore, demonstrations using a realistic phantom could increase patient compliance in future clinical settings. For these purposes, a model of the human larynx including vocal fold actuation for LAR simulation was developed in this work. The combination of image processing based on a custom algorithm and individual motorization of each vocal fold enables spatio-temporal droplet impact detection and controlled vocal fold adduction. To simulate different LAR pathologies, the current implementation allows to individually adjust the reflex onset latency of the ipsi- and contralateral vocal fold with respect to the automatically detected impact location of the droplet as well as the maximum adduction angle of each vocal fold. An experimental study of the temporal offset between desired and observed LAR onset latency due to image processing was performed for three average droplet masses based on highspeed recordings of the phantom. Median offsets of 100, 120 and 128 ms were found (n=16). This offset most likely has a multifactorial cause (image processing delay, inertia of the mechanical components, droplet motion). The observed offset increased with increasing droplet mass, as fluid oscillations after impact may have been detected as motion. In future work, alternative methods for droplet impact detection could be explored and the observed offset could be used for compensation of this undesirable delay.
Computer Assisted Auscultation System for Phonoangiography of the Carotid Artery
Authors: Sühn Thomas , Mahmoodian Naghmeh , Sreenivas Arathi , Maldonado Iván , Spiller Moritz , Boese Axel , Illanes Alfredo , Friebe Michael , Bloxton Michael
Published: September 2019

Cerebrovascular diseases such as stenosis, atherosclerosis or distention of the carotid artery are accountable for about 1 million death per year across Europe. Diagnostic tools like ultrasound imaging, angiography or magnetic resonance-based imaging require specific hardware and highly depend on the experience of the examining clinician. In contrast auscultation with a stethoscope can be used to screen for carotid bruits - audible vascular sounds associated with turbulent blood flow - a method called phonoangiography. A reliable auscultation setup is prerequisite to ensure high signal quality, adequate processing and the objective evaluation of this audible signal. We propose a computer assisted auscultation system for the acquisition of vascular sounds of the carotid. The system comprises of an auscultation device, a smartphone-based control application and cloud-based signal analysis and storage. It is designed to facilitate the objective assessment, screening and monitoring of long-term changes in the vessel condition based on auscultation of the carotid artery.
Reconstruction accuracy of an automated serial cross-sectional preparation technique for morphological human temporal bone imaging
Authors: Hügl Silke , Erfurt Peter , Lenarz Thomas , Majdani Omid , Rau Thomas S.
Published: September 2019

Detailed knowledge about the three-dimensional morphology of the human cochlea and its intra-cochlear bony and soft-tissue structures is essential for development of new cochlear implant electrode carriers. A manual cross-sectional preparation and imaging technique, hereinafter referred to as “microgrinding”, uses human temporal bone samples embedded in epoxy resin. This process was automated to shorten the time needed for preparation and to increase reproducibility. In this study, reconstruction accuracy of the automated microgrinding technique was determined. Four assemblies of LEGO® bricks were used as artificial samples to analyze the resulting reconstruction accuracy of the whole procedure including embedding, preparation and image registration. The outer surfaces of the samples were measured using a portable coordinate measuring machine by manually choosing points on each surface. After embedding the samples in epoxy resin, following the protocol for human temporal bone samples, preparation using the automated microgrinding was performed with a slice thickness of 50μm. Pixel-spacing within an image was 11.5μm/px. The samples were identified within the dataset using threshold segmentation. Subsequently, points were manually chosen on each surface of the segmented samples. Planes, angles between planes and distances between corners were calculated for the physical and the digital samples. Deviation of the digitally derived measures compared to the physically derived ones describe the reconstruction accuracy of the automated microgrinding process. Parallel planes had a deviation of 0.5° ± 0.5° (range: 0 - 2.9°). Orthogonal planes, whose line of intersection is parallel to the direction of milled abrasion, had a deviation of 0.8 ° ± 0.5 ° (range: 0 - 2.1°), whereas such orthogonal planes whose line of intersection is parallel to the documented sample surface had a deviation of 0.4° ± 0.3 ° (range: 0 - 1.7 °). Distances between corners had an absolute deviation of 0.1 mm ± 0.1mm (range: 0 - 0.6mm), which corresponds to a relative deviation of 1% ± 1% (range: 0 - 6.5%). This study shows a highly accurate sample preparation using an automated microgrinding technique as an essential prerequisite for three-dimensional morphological imaging.
Preliminary Study on 3D printing of PEGDA Hydrogels for Frontal Sinus Implants using Digital Light Processing (DLP)
Authors: Mau Robert , Nazir Jamal , John Samuel , Seitz Hermann
Published: September 2019

Digital Light Processing (DLP) enables high precision 3D-printing of photopolymers and holds promising potential for patient-specific implant solutions. On the material side, Poly(ethylene glycol) diacrylate (PEGDA) has emerged as an interesting material for use in biomedical applications. For adequate photopolymerization, a photoinitiator and a light absorber are necessary, using welldefined concentrations. This study shows preliminary results of DLP 3D-printing of different PEGDA hydrogel compositions with varying water content (90; 70; 50; 30; 10; 0 % w/w) as well as varying concentrations of a photoinitiator and a light absorber. Printing performance and accuracy are investigated by printing rectangular test samples as well as an anatomically customised tubular frontal sinus implant prototype. For basic mechanical characterisation, the hardness of the printed hydrogels is investigated using a Shore A durometer. The results show a decrease in printing accuracy and hardness with an increasing water content of the composition. There is a need to use a light absorber to reach high printing accuracy. This leads to a need for increasing photoinitiator concentration and prolonged light exposure to achieve proper printing performance.
Superparamagnetic Iron Oxide Nanoparticles
Authors: Lüdtke-Buzug Kerstin , Penxová Zuzana
Published: September 2019

The direct detection of the spatial distribution of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) as a tracer for Magnetic Particle Imaging (MPI) enables threedimensional functional images with high spatial and temporal resolution. The commercially available tracers have not been developed primarily for MPI. Therefore, they do not sufficiently contribute to the desired image quality. Hence, optimizing the SPIONs during the production process is of interest. A peculiarity of the here presented synthesis method - the alkaline coprecipitation - is that this process takes place under ultrasonic control. The use of ultrasound creates extraordinary reaction conditions through sonochemical phenomena, such as formation, growth and implosive collapse of cavitation bubbles within a liquid. In addition, the ultrasonic waves and the oscillation of the medium improve the mixing process and thus ensure the homogenization during the synthesis. The objective of this study is the variation of ultrasonic frequencies and the type of used dextran as coating material, to provide SPIONs with better performance for MPI and more suitable properties for in vivo application. The focus of the optimization is to increase the magnetite core size while simultaneously reducing the hydrodynamic size. The experiments have shown that both, the ultrasound frequency and the molecular weight of used dextran, influence the properties of the SPIONs.
Covalent coupling of polymers as drug coatings on silicone surfaces for future applications
Authors: Wulf Katharina , Teske Michael , Arbeiter Daniela , Eickner Thomas , Grabow Niels , Paasche Gerrit , Lenarz Thomas
Published: September 2019

Insertion of a cochlear implant (CI) into the scala tympani evokes electrode insertion trauma that can result in mechanical damage of the lateral and medial wall and causes ingrowth of fibrous tissue on the implant surface. In consequence, it is of great clinical interest to modify the silicone surface of CI electrodes in order to inhibit and minimize the overgrowth by connective tissue. In this case, the covalent coupling of bifunctional polymers on common CI silicone surfaces is a versatile method to influence the implant cell interaction, but is still a challenge due to the chemically unreactive properties of silicone. We present a sophisticated method to apply a biodegradable polymer coating, such as polylactide or polyhydroxybutyrate, on silicone surfaces to generate a drug delivery system using a covalently bound intermediate layer. The adhesive coatings were applied via spincoating processes with different adherence to the intermediate layer. Changes in surface morphology were investigated by comparison of pure silicone and coated silicone. Specific polymer bands of the infrared spectra were detected by IR spectroscopy. Results indicate a complete coating with polylactide or polyhydroxybutyrate. The presented method is a versatile tool for the coating of silicone CI electrodes with degradable polymer layers.
Formation and characterisation of hydrogel diffusion channels for directed drug delivery
Authors: Eickner Thomas , Kohse Stefanie , Illner Sabine , Oschatz Stefan , Teske Michael , Rekowska Natalia , Senz Volkmar , Schmitz Klaus-Peter , Grabow Niels
Published: September 2019

Drug Delivery Systems (DDS) are frequently operating in a surrounding liquid environment, such as blood in the case of drug-eluting stents or perilymph in the case of cochlear implants. However, there is also a demand for systems with sustained drug release in predominantly dry environments, mostly consisting of ambient air. Examples are the treatment of diseases located in the middle ear or the paranasal sinuses. On the one hand, due to the lack of transportation media, the functionality of a polymer/drug combination for delayed release would be limited in such environments. On the other hand, these environments are generally equipped with mucus membranes. Hence, a somewhat humid surrounding is ensured. In this study, a concept of a hydrogel equipped DDS for drug delivery through the round window membrane is presented, addressing two objectives. First objective is to ensure the drug transport by serving as a diffusion channel. For instance the route to the drug target destination, the round window membrane, can be provided by a hydrogel. The second objective is to ensure the adhesion to the membrane. Two promising approaches are presented in this study: The photo induced immobilisation of PEGDA700, as well as the immobilisation of chitosan on poly(l-lactid) (PLLA). For both approaches PLLA specimen had to be modified with oxygen plasma followed by activation for crosslinking with subsequent immobilisation of the hydrogel. With these methods a layer thickness of at least 5 μm was achieved. All steps were characterized with contact angle measurements. After the immobilization of the hydrogel, the swelling factor, as well as the layer thickness was examined.
Post-processed chemical treatment of polyimide electrospun nonwovens with ethylenediamine for biomedical applications
Authors: Oschatz Stefan , Arbeiter Daniela , Eickner Thomas , Grabow Niels , Illner Sabine
Published: September 2019

The generation of electrospun nonwovens from polyimide (PI) is challenging as the fibers are prone to distinct delamination. In consequence, the resulting nonwoven material has particularly low structural integrity and loose fibre interlocking, demanding for a follow-up treatment, such as high temperature thermal treatment. In this work, a facile method for a post-processed treatment of PI nonwoven is presented in order to obtain a mechanically stable material while maintaining the characteristics of the electrospun nonwoven. The procedure was performed using a solution of EDA in methanol at 37 °C and ambient pressure to achieve a modified fiber interaction. Overall, the developed protocol opens new possibilities in the processing of PI into delamination-free nonwovens. Potential adverse effects of a high temperature thermal treatment are being avoided, and new applications in the field of medical devices may become accessible.
Investigation of mechanical and magnetophoretic focusing for magnetic flow cytometry
Authors: Liu Jan , Reisbeck Mathias , Hayden Oliver
Published: September 2019

As an alternative to optical flow cytometry, magnetic flow cytometry has emerged in recent years for single cell analysis with sheath-less flow conditions. Instead of measuring scattered light, magnetic fields of magneticallylabeled cells are recorded and analyzed. To determine microfluidic opportunities to manipulate cell trajectories for in-situ cell focusing we use mechanical guiding structures and magnetophoretic forces. A 3D-microfluidic particle simulation has been implemented that revealed parameters ensuring the crucial balance between hydrodynamic drag and magnetophoretic forces. Experimental measurements verified the 3D particle tracking simulation.