bluuebunny/crossref_metadata_2025 huggingface dataset:
The longitudinal method: study of the change process in qualitative studies in management sciences
Authors: Moufdi Nada , Mansouri Ali
Published: August 2021

Considered as one of the tools available to the researcher to understand and analyze the process and course of phenomena, the longitudinal qualitative study remains, despite its importance, an ignored research protocol and is rarely used in management sciences. This contribution aims to provide clarification elements regarding the definition, typology, data collection methods and analysis of results in longitudinal qualitative research. It provides a helpful guide for conducting and reviewing longitudinal studies in these sciences.
Digital entrepreneurship in Morocco: measurement model validation
Authors: Saoura Zakia , Abriane Ahmed , Moumen Aniss
Published: August 2021

According to the 2017 Global Entrepreneurship Monitor report, there are 6.5 million adults aged 18-64 planning to start an entrepreneurial career by 2020. However, the gap between attempt and effective creations remains one of the largest within Arab countries (40% versus 9%). Given these statistics, we ask the question about the profile of the Moroccan entrepreneur. In this paper, we opted for a quantitative research methodology on an exploratory sample. We distributed a questionnaire to a sample of eighty Moroccan entrepreneurs representing different regions of Morocco. The objective of our study is to validate a measurement scale of three dimensions: 1/ entrepreneurial motivations, 2/ skills, and 3/ behaviour in the Moroccan context. To do so, we present, in the first part, a literature review on digital entrepreneurship. Then, we establish a state of the art of entrepreneurship in Morocco. Then, we show our methodology. Finally, we reveal and discuss the results of our study.
The 3D Printing solutions during the COVID-19 pandemic in 2020/2021
Authors: Yaagoubi H. , Abouchadi H. , Janan M. Taha
Published: August 2021

The 2019-2021 coronavirus pandemic (COVID-19), which began in the city of Wuhan in China, towards the end of 2019. As of March 12, 2020, the World Health Organization ordered the disease of coronavirus 2019 (COVID-19) as a pandemic, at the time of its composition, has spread to more than 180 countries on the planet. The number of COVID-19 patients is on the rise worldwide; given the high number of patients and the disruption of the production network; this has created a shortage of clinical parts and personal protective equipment; the 3D printing has endorsed its role in this area. 3D printing continues to provide healthcare workers with missing equipment for example, millions of face shields, face veils, valves, nasopharyngeal swabs and more have been made using 3D printing, in this article, we will share the contribution and experience of the 3D printing sector in the medical sector and a survey has been carried out of the studies to give a global view on the way and pace of use of this technology in the World during this health crisis.
Analysis of sentiments conveyed through Twitter concerning COVID-19
Authors: Chiny Mohamed , Chihab Marouane , Bencharef Omar , Chihab Younes
Published: August 2021

Due to the social and economic fallout from the COVID-19 pandemic, we sought to gauge the attitudes of social network users, in this case, Twitter, towards the topic using a sentiment analysis approach. We collected 178,683 tweets using the Twitter API based on queries for the high-frequency hashtag #covid19. After the preprocessing step, we classified them in a binary way (positive and negative) and according to their intensity (valence) using the VADER model and then the NRCLex dictionary, which allows us to classify feelings according to their affective class. The results suggest that overall, the feelings detected through the tweets are positive. In addition, users seem to be interestedin the pandemic as a trend rather than as a topic related to other social or economic aspects.
Development of peripheral regions in the context of the bioeconomy paradigm
Authors: Yarkova Yuliana , Stoykova Blaga , Markov Nedelin
Published: August 2021

The existence of peripheral regions is a significant challenge for regional development management. These regions have a specific economic and social profile, and their complex development is accompanied by the consideration of a number of factors that have a strong local significance and, in most cases, a dampening effect. The aim of the present study is to follow the trends in the development of a typical peripheral region in Bulgaria, focusing on identifying the potential of the regional economy for transformation to bioeconomic and circular orientation. The object of the study is the region Strandzha-Sakar, and the subject of the study is the potential for bio-economic and circular orientation based on specific traditional assessments, measuring both economic and demographic trends and local economic traditions.
The just transition of the European Green Deal and the development of the regions with intensive coal mining (example of Marishki Basin – Bulgaria)
Authors: Yarkova Yuliana , Yarkov Dobri , Tsacheva Stoyanka
Published: August 2021

The just energy transition is an opportunity to drive a very important process of transformation of the traditional linear, waste holding economy based on fossil fuels and polluting transport to a new type of economy, driven by the circularity bio-, RES economics paradigm and environmentally responsible transport. The purpose of this study is to contribute to the identification of the direction, factors and mechanisms of the energy transition in the Marishki Basin – Bulgaria, as well as to formulate proposals related to the development of territorial plans for a just transition and the integrated development plans of the municipalities. The methods that have been applied to achieve the purpose of the research are qualitative – desk research (search for general information about the object and the subject of the research – offline and online) and an in-depth interview with leading experts (regarding the process of transition and transformation of the Maritsa East complex). In addition to subjective expert assessments, objective statistical data for the region and for the Maritsa East complex were used for the needs of the research. The present work summarizes the views of the leading experts and makes suggestions regarding the future economic development of the region concerned and its energy transition. The Marishki Basin is a region within which it is necessary to develop and implement a system of projects and measures to be set out in the integrated development plans of the municipalities concerned and to be part of the territorial plans for a just transition. The leading sectors are to bet agri-energ biotechnology, aquaponics, “hydrogen valleys”, digital industries, robotics, urban agriculture, tourism and other activities that would create an innovative economic organism in the region.
Bioeconomy as an innovative approach to rural development in the context of Common Agricultural Policy in EU
Authors: Turlakova Teodorina
Published: August 2021

Bioeconomy is an innovative approach in the economy of the region, aimed at integrating the available natural and labour resources, production facilities, the achievements of science in the field of innovation technologies. These are related to the production of material goods, the conversion of production and energy in the direction of fuller utilization of organic and mineral sources as a raw material resource for achieving sustainable development in the field of production and consumption, stable economic development and growth living standards of the population while protecting the environment and resources. The aim of the report is to analyze the possibilities for applying the bioeconomy in rural areas through research and innovation, stimulating private investment, developing new value chains and engaging stakeholders. The role of the CAP in supporting and financing activities of the bio and circular economy models is argued.
Covid-19 Pandemic as a Contemporary Challenge and Determinant of EU Citizens’ Priorities
Authors: Pastarmadzhieva Daniela , Angelova Mina
Published: August 2021

The challenges caused by the Covid-19 pandemic have numerous dimensions. Although the public and the health care systems are the most affected by the situation, the indirect consequences may last longer. One of the areas, which has been put under stress is the relations between the society and the state. These relations determine the overall stability and performance of the states, which is also valid for supranational entity as the European Union (EU). In order to protect its stability, the member states of the latter need to respond the expectation and priorities of their citizens. Thus, the purpose of the current study is to identify if there is a change in the priorities of the EU citizens and what is it. The object of the study are the countries, members of the European Union, studied from 2016 to 2020. Focus of the research is the topics, most relevant for the citizens of EU member states. The data used is from Euro barometer and for the purposes of the analysis statistical methods (frequencies and cross tables) and comparative approach are used. The results show that generally the top priorities of the EU citizens are the same, but their intensity varies across the studied years.
Brownfield Reuse Investment as a Tool for Limiting the Territorial Expansion of Settlements in Bulgaria
Authors: Gospodinova Anna
Published: August 2021

The goal set by the author of the study is to consider the good European practices in the remediation and reuse of Brownfields and on that basis to outline the possibilities for the use of these practices in Bulgaria in order to limit the territorial expansion of settlements (populated places) at the expense of non-urbanized areas. The specific character of the issue under study determines the following research methods as most suitable: the document analysis method; the comparison method; the methods of analysis and synthesis. There are laid down the possibilities for Brownfield reuse in Bulgaria. The reuse of the so-called brownfields combines the advantages of the environmental, the economic and the social development as it results in a more sustainable development of settlements, as well as in reduced reclamation and building up of green areas and non-urbanized land for the erection of new buildings and the development of infrastructure (social as well as technical).
Impact of COVID-19 on the tourism sector in Bulgaria: state, measures to deal with the effects of pandemic
Authors: Zheleva Violetka , Mutafov Emil
Published: August 2021

Nowadays the tourism sector is facing challenges from different type. The physical limitations in travel, overnight stays and public health affected all forms of tourism. Since the outbreak of the COVID-19 pandemic, industries worldwide have been in a state of stagnation, collapse and insecurity which can be seen mostly in tourism sector. According to global expectations physical and mental health care are top priority, so forms of alternative tourism will be the focus of the tourism sector in near future. Current research is relying on hypothesis that alternative forms of tourism are more preferable than the mass tourism, since it is less widespread and consumers would find this form safer from a health point of view. Results will provide detailed overview of tourism sector in Bulgaria and its distribution.
COVID-crisis: opportunities vs challenges for innovative transformations and self-development
Authors: Piatnytska Galyna , Hryhorenko Oleh , Zhukovska Valentyna
Published: August 2021

Topical issues related to the identification of factors influencing innovative transformations during the COVID-crisis have been highlighted. The aim of the study is to identify opportunities and challenges for innovative transformations and self-development in the context of the COVID-crisis. The methods of systems analysis, surveys and synthesis were used. Research data confirmed that the pandemic has not fundamentally changed the fact that the potential of breakthrough innovations continues to exist. It is not expedient for enterprises to abandon R&D and innovations, despite the current challenges. Innovative transformations require not only financial support, but also human resources and innovative ideas. According to our survey of students in 2020, it was identified that today they can be divided into those who are: 1) able to develop and try to solve problems regardless of the situation; 2) able to take advantage of opportunities but may be unable to resist threats and solve problems; 3) unable to make constructive decisions and think creatively in the COVID-crisis. To ensure progressive innovation development, the number of the first group should be the largest, and the third – the smallest. It is concluded that currently, the situation for innovative transformations is ambiguous. The paradox of imaginary and real positioning is revealed. This showed discrepancies between how potential business managers assess opportunities and respond to challenges in the COVID-crisis.
Impact assessment of European policies for combating payment card fraud on the Stakeholders
Authors: Atanasova Magdalena
Published: August 2021

The security of non-cash payment instruments is a key factor for the economic stability of the European Union. Crime with electronic payment instruments and related illegal activities affect the Digital Single Market and the financial interests of the European Union. Organized crime groups generate € 1.44 billion a year in the Community from payment card fraud, with illegal proceeds reinvested in illegal activity and not recovered. The current scientific article aims to assess an ex-post impact of European policies for combating payment card fraud and counterfeiting on the stakeholders, in particular payment process participants. The goal is to establish the policy efficiency by analyzing the cost and benefits of the specific policy for the participants. A methodology has been developed, based on a multidisciplinary approach. The following scientific methods are used: case study; research and review of legal and other documents; content analysis of strategic and annual reports and assessments; analysis of qualitative indicators and secondary analysis of empirical data. The results of the survey show that the cost of crime prevention and control measures is high, but responsibility for costs is shared between the public and private sectors, and consumers. Strengthening cooperation between stakeholders will lead to higher policy benefits and lower costs.
Justification of the need to implement intelligent warehouse systems in fish processing
Authors: Pencheva Velizara , Hvarchilkov Vladimir , Asenov Asen , Beloev Ivan , Grozev Dimitar , Yankov Emil , Hristakov Ivaylo
Published: August 2021

The paper reviews the existing state of fishing worldwide and in Bulgaria. Then the scheme is determined, according to which the live fish moves from the water basins in which it is raised and lives until it is sent to the store network and the end customers. As a result of the studies conducted, two-week points in the transitional warehouses have been identified. They are characterized by four main indexes: oxygen, temperature, Ph acidity and water level in the container. It these four are not within the determined allowances, it is possible the quality of the environment for storing the live fish to be deteriorated, which can lead to premature death of the fish. In this respect, a regression model with the four main indexes that are to be monitored and maintained within the allowance values has been created for achieving high quality of the storage environment. For the regression model has been determined a coefficient of determination R = 0.9131, and a Fisher’s criterion, which is 5.0143 compared to the one in the Table - 2.5802, which shows that the model is adequate and can be used for further calculations. For the practical solution of the problem, it has been proposed to introduce an intelligent information system in the transitional warehouses for storing live fish before the end processing. The system proposed will be used to monitor and control the four main indexes and to improve the conditions for storing live fish when it is moved along the chain of fish farms to the warehouses for end processing.
Behavioural changes of the business parties in the tourist sector after the implementation of the measures for overcoming the Covid-19 crisis
Authors: Grigorova Zlatka , Dzhabarova Yulia
Published: August 2021

The harmful consequences of Covid-19 mostly influenced the Tourist sector worldwide. The negative trends shaped the fearful reality for all related businesses and involved parties and let them face the challenge to overcome this cruel environment of existence and streamline their future survival and development. To prevent the companies from the environmental threats, and to support their recovery and future stable existence, many different measures at national and regional level were taken. The paper aims at clarifying the influence and efficiency of the carried-out measures in the Tourist sector. The applied methodology is based on the comparative analysis. For this purpose, an online research was conducted in two different periods, and the data was registered through questionnaires containing three structured thematic blocks. The sample consists of 73 representatives, presented by different parties from the Tourist sector in the Plovdiv region. The survey was conducted in the period of April 2020 – April 2021. The provided conclusions and recommendations could serve all institutions at national and regional level, as well as business organizations in their policies. The policy makers and the policy recipients could both benefit from the results of the study in order to reply adequately to the challenges of the surrounding environment and consumer requirements, and thus, to be able to adapt their business and marketing strategies.
The operational and research DTM-2020 thermosphere models
Authors: Bruinsma Sean , Boniface Claude
Published: August 2021

Aims: The semi-empirical Drag Temperature Models (DTM) predict the Earth’s thermosphere’s temperature, density, and composition, especially for orbit computation purposes. Two new models were developed in the framework of the H2020 Space Weather Atmosphere Models and Indices (SWAMI) project. The operational model is driven by the trusted and established F10.7 andKpindices for solar and geomagnetic activity. The so-called research model is more accurate, but it uses the indices F30 and the hourly Hpo, which are not yet accredited operationally.Methods: The DTM2020 models’ backbone comprises GOCE, CHAMP, and Swarm A densities, processed by TU Delft, and Stella processed in-house. They constitute the standards for absolute densities, and they are 20–30% smaller than the datasets used in the fit of DTM2013. Also, the global daily mean TLE densities at 250 km, spanning four solar cycles, were now used to improve solar cycle variations. The operational model employs the same algorithm as DTM2013, which was obtained through fitting all data in our database from 1967 to 2019. Because of the Hpo index, which is not available before 1995, the coefficients linked to the geomagnetic activity of the research model are fitted to data from 2000 to 2019. The algorithm was updated to take advantage of the higher cadence of Hpo. Both models are assessed with independent data and compared with the COSPAR International Reference Atmosphere models NRLMSISE-00, JB2008, and DTM2013. The bias and precision of the models are assessed through comparison with observations according to published metrics on several time scales. Secondly, binning of the density ratios are used to detect specific model errors.Results: The DTM2020 densities are on average 20–30% smaller than those of DTM2013, NRLMSISE-00, and JB2008. The assessment shows that the research DTM2020 is the least biased and most precise model compared to assimilated data. It is a significant improvement over DTM2013 under all conditions and at all altitudes. This is confirmed by the comparison with independent SET HASDM density data. The operational DTM2020 is always less accurate than the research model except at 800 km altitude. It has comparable or slightly higher precision than DTM2013, despite using F10.7 instead of F30 as solar activity driver. DTM, and semi-empirical models in general, can still be significantly improved on the condition of setting up a more complete and consistent total density, composition, and temperature database than available at this time by means of a well-conceived observing system.
Therapieoptionen und outcome bei idiopathischen entzündlichen Muskelerkrankungen
Authors: Unger Leonore
Published: August 2021

Die idiopathischen entzündlichen Muskelerkrankungen (IIM) sind eine sehr heterogene Gruppe, die sich immer besser differenzieren lässt. Damit eröffnen sich mehr Möglichkeiten für gezieltere Therapien, die zum einen auf die Veränderung pathogenetischer Faktoren gerichtet sind. Zum anderen sollen sie Krankheitsaktivität vermindern, Muskelaufbau fördern, Organschäden verhindern und Lebensqualität verbessern.

Die folgende Übersichtsarbeit fasst die vorhandenen Daten zu bereits angewandten Behandlungen in der Praxis zusammen und gibt einen Ausblick auf zukünftige Alternativen.

Für die Polymyositis (PM) und Dermatomyositis (DM) sind Glukokortikoide weiter unverzichtbarer Therapiebestandteil. Eine frühe Kombination mit konventionellen DMARDs hat sich durchgesetzt. Die ProDerm- Studie stellt für die Immunglobulintherapie in der Praxis eine gute Basis dar. Rituximab (RTX) löst Cyclophosphamid (CYC) bei schweren Verlaufsformen immer mehr ab.

Für Abatacept, Jak-Kinase-Hemmer, Apremilast, Sifalimumab und Lenabasum müssen vielversprechende erste Ergebnisse durch weiter Studien untermauert werden. Anspruchsvoll ist die Behandlung bei extramuskulärer Beteiligung. Von großem Interesse ist der zukünftige Stellenwert von Nintedanib bei der interstitiellen Lungenerkrankung im Rahmen einer Myositis (IIM-ILD).

Die Therapie der Einschlusskörperchen- Myositis (IBM) ist immer noch eine große Herausforderung. Zahlreiche Studien haben bisher nicht überzeugend zu einer Besserung der Prognose führen können. Spätestens bei therapierefraktärem Verlauf sollte an eine Malignom- assoziierte Myositis gedacht werden. Gelegentlich verbirgt sich auch eine hereditäre Myopathie hinter einer, zum Beispiel durch einen Infekt oder Überlastung getriggerten, Myositis.

Komplikationen im Verlauf, wie Dysphagie, Infektionen, Myokardbeteiligung stellen keine Seltenheit dar. Häufig besteht Multimorbidität. Eine interdisziplinäre Zusammenarbeit in einem kompetenten Team, in dem erfahrene Physio-, Ergo- und Psychotherapeuten fester Bestandteil sind, ist unabdingbar für eine erfolgreiche Begleitung dieser Patienten.
Long-term outcome after EUS-guided radiofrequency ablation: Prospective results in pancreatic neuroendocrine tumors and pancreatic cystic neoplasms
Authors: Barthet Marc , Giovannini Marc , Gasmi Mohamed , Lesavre Nathalie , Boustière Christian , Napoleon Bertrand , LaQuiere Arthur , Koch Stephane , Vanbiervliet Geoffroy , Gonzalez Jean-Michel
Published: August 2021

Background and study aims Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) for pancreatic neuroendocrine tumors (NETs) and intraductal pancreatic mucinous neoplasia (IPMN) with worrisome features or high-risk stigmata (WF/HRS) has been evaluated in few series with short-term outcomes. This studyʼs primary endpoint was to assess the long-term efficacy of EUS-RFA in patients with NETs or pancreatic cystic neoplasms (PCNs) over at least 3 years.

Patients and methods Twelve patients had 14 NETs with a mean 13.4-mm size (10–20) and 17 patients had a cystic tumor (16 IPMN, 1 MCA) with a 29.1-mm mean size (9–60 were included. They were treated with EUS-guided RFA, evaluated prospectively at 1 year, and followed annually for at least 3 years.

Results The mean duration of follow-up was 42.9 months (36–53). Four patients died during follow-up (17–42 months) from unrelated diseases.

At 1-year follow-up, and 85.7 % complete disappearance was seen in 12 patients with 14 NETs. At the end of follow-up (45.6 months), complete disappearance of tumors was seen in 85.7 % of cases. One case of late liver metastasis occurred in a patient with initial failure of EUS-RFA. At 1-year follow-up, a significant response was seen in 70.5 % of 15 patients with PCNs. At the end of the follow-up, there was a significant response in 66.6 % with no mural nodules. Two cases of distant pancreatic adenocarcinoma unrelated to IPMN occurred.

Conclusions EUS-RFA results for pancreatic NETs or PCNs appear to be stable during 42 months of follow-up.
Feasibility of an EUS e-training course with live cases
Authors: Dhir Vinay , Udawat Priyanka , Shah Rahul , Alahari Aruna
Published: August 2021

Background and study aims One-on-one endoscopic ultrasound (EUS) mentorship was not possible at most institutions during the COVID-19 pandemic. We decided to test the feasibility of structured training in EUS with virtual e-classes with live cases. The aim of this study was to assess the feasibility of a virtual EUS training course with objective end points.

Patients and methods Twenty-one trainees were trained on a virtual platform over 16 classes of 90 minutes each, over 3 months. The virtual training screen had two equal parts, one showing the endoscopist’s hand movements, and another the resultant EUS display. The course curriculum included EUS anatomy of the mediastinum, pancreatico-biliary region and rectum. The assessment was done on videos of procedures performed by trainees.

Results Twenty trainees performed 251 EUS procedures (range 8–25, mean 12.5 ± 4.9) at their institutions. At the end of the course, all students (100 %) could maneuver the echo-endoscope through to the duodenum. Fifteen trainees sent a video for final assessment. The successful specified area identification rates were 12 of 15 (80 %) for the subcarinal space, 10 of15 (66.6 %) for the head of the pancreas, 10 of 15 (66.6 %) for the common bile duct, and nine of 15 (60 %) for the tail of pancreas. The success rate of ability to get appropriate windows was 10 of 15 (67 %) for the subcarinal space, eight of 15 (53.3 %) for the head of the pancreas, seven of 15 (46.6 %) for the common bile duct and six of 15 (40 %) for the tail of pancreas. No adverse events were reported.

Conclusions A virtual EUS training course with live cases appears feasible. It allows the possibility of training a large number of students. Further evaluation is needed, especially of virtual assessment methods and training benchmarks.
Video clips compared with high-definition still images for characterization of colorectal neoplastic lesions: a randomized comparative prospective study
Authors: Pioche Mathieu , Jacques Jérémie , Héroin Lucile , Rivory Jérôme , Ponchon Thierry , Legros Romain , Albouys Jérémie , Chaussade Stanislas , Gronier Olivier , Reimund Jean-Marie , Fabacher Thibaut , Sautereau Denis , Dumeirain Franck ,   and the French Society of Digestive Endoscopy (SFED)
Published: August 2021

Background and study aims Accurate real-time characterization of colorectal neoplastic lesions (CNLs) during colonoscopy is important for deciding appropriate treatment. No studies have evaluated whether still images or video clips are better for characterization. We compared histological predictions and size estimations of CNLs between two groups of gastroenterologists: one viewing still images and the other viewing video clips.

Materials and methods Participants were shown 20 CNLs as either 3–5 still images or a video clip. Three endoscopy experts obtained the images using high-definition white light and virtual chromoendoscopy without magnification. Stratified randomization was performed according to experience. For each lesion, participants assessed the size and histological subtype according to the CONECCT classification (hyperplastic polyp [IH], sessile serrated lesion [IS], adenoma [IIA], high-risk adenoma or superficial adenocarcinoma [IIC], or deeply invasive adenocarcinoma [III]). The correct histological status and size were defined by the pathology reports or combined criteria between histology and expert opinion for high-risk adenoma or superficial adenocarcinoma (CONECCT IIC).

Results 332 participants were randomized and 233 performed the characterization. Participants comprised 118 residents, 75 gastroenterologists, and 40 endoscopy experts; 47.6 % were shown still images and 52.4 % viewed video clips. There was no statistically significant difference between the two groups in histological prediction, our primary end point. However, the lesion size was better assessed using still images than video clips (P = 0.03).

Conclusions Video clips did not improve the histological prediction of CNLs compared with still images. Size was better assessed using still images.
Ursache von Muskelschwäche: Spektrum neuromuskulärer Erkrankungen und diagnostisches Vorgehen
Authors: Fitzner Maren , Schmidt Jens
Published: August 2021

Das Leitsymptom der muskulären Schwäche kann auf das Vorliegen einer neuromuskulären Erkrankung zurückzuführen sein, findet sich jedoch auch bei einer Reihe anderer Faktoren wie Elektrolytveränderungen, Vitaminmangel, Schilddrüsenerkrankungen, Bewegungsmangel oder bei unerwünschten Arzneimittelnebenwirkungen. Einer gründlichen Anamnese und körperlichen Untersuchung kommt daher in der differentialdiagnostischen Abklärung eine große Bedeutung zu. Die zeitliche Entwicklung, das Verteilungsmuster sowie Begleitsymptome erlauben oftmals bereits eine erste diagnostische Einordnung. Bei begründetem Verdacht auf das Vorliegen einer neuromuskulären Erkrankung sollte die weiterführende Diagnostik durch einen Neurologen oder ein neuromuskuläres Zentrum erfolgen. Zu den wichtigsten neuromuskulären Erkrankungen mit Leitsymptom einer muskulären Schwäche gehören die neuromuskulären Übertragungsstörungen, Neuropathien, erbliche und erworbene Myopathien sowie Motoneuronerkrankungen. Diese Übersicht stellt die wichtigsten Ursachen für eine muskuläre Schwäche zusammen und zeigt das zu empfehlende diagnostische Vorgehen auf.
Biomarker und Histologie bei idiopathischen inflammatorischen Myopathien
Authors: Schneider Udo , Stenzel Werner , Stuhlmüller Bruno
Published: August 2021

Die idiopathischen inflammatorischen Myopathien (IIM) sind eine Gruppe entzündlicher Muskelerkrankungen für deren Diagnosestellung, Verlaufsbeurteilung, Prognoseabschätzung und Risikostratifizierung Biomarker eine jeweils essentielle Rolle spielen. Biomarker in diesem Kontext können sowohl „herkömmliche“ serologische Marker wie Muskelenzyme oder Autoantikörper, histologische Marker wie entitätsspezifische inflammatorische Muster, aber auch genomische und genetische Marker sein. Der vorliegende Artikel gibt einen Überblick über bewährte und innovative Marker.
Dermatologische Differentialdiagnosen von idiopathischen entzündlichen Muskelerkrankungen
Authors: Sunderkötter Cord , Golle Linda
Published: August 2021

Die Hautsymptome sind für die Differenzialdiagnose der Myositiden wichtig, da sie einmal entscheidend für die Unterscheidung der Dermatomyositis und des Anti-Synthetase-Syndroms von den anderen Autoimmun-Myositiden sind, und da sie bei Myositiden im Rahmen von Overlap Syndromen Hinweise auf die zugrunde liegenden Autoimmunerkrankungen (Lupus erythematodes, systemische Sklerose u. a.) geben können. Daher sollte bei Patienten mit einer Myositis eine genaue Inspektion der Haut erfolgen. Fast pathognomonisch für die Dermatomyositis ist die Trias aus symmetrischem, fliederfarbenem Erythem auf den Oberlidern (heliotropes Erythem), Erytheme oder flache Papeln oder Plaques über den proximalen interphalangealen und metacarpophalangealen Fingergelenken (so genannte Gottron Papeln) und Erytheme über Knien, Ellenbogen oder Knöcheln (so genanntes Gottron Zeichen). Daneben gibt es eine Reihe weiterer, typischer Hautsymptome (peitschenabdruckartige Erytheme, Poikilodermie, dystrophe Nagelhäutchen, Vaskulitiden, Juckreiz). Beim Anti-Synthetase-Syndrom treten neben einem Raynaud Phänomen als charakteristisches Symptom die sog. Mechanikerhände („mechanic‘s hands“) auf, d. h. Hyperkeratosen und Fissuren lateral an den Fingern. Klinisch und histologisch sind die Hautsymptome beim LE nicht eindeutig von denen der Dermatomyositis zu trennen, auch wenn es einige Unterschiede gibt. Die Hauteffloreszenzen sprechen nicht immer gut auf die Therapien der Myositis an. Ein Rückgang wurde unter Glukokortikoiden, Methotrexat, IVIG, Mycophenolatmofetil und Rituximab beobachtet. Als systemische Therapie gegen die Hautbeteiligung hat Hydroxychloroquin Wirksamkeit gezeigt, manchmal nur in Kombination mit Mepacrin. Zur zusätzlichen topischen Behandlung eignen sich Glukokortikoide und Calcineurin-Inhibitoren. Eine generelle Maßnahme ist der konsequente Sonnenschutz.
Ru(II)-Catalyzed C–H Activation Reaction between 2-Phenyl­quinazolinone and Vinylene Carbonate
Authors: Guan Mei , Wu Yong , Chen Yuncan , Huang Xin , Xu Yingying , Li Jianglian , Lai Ruizhi
Published: August 2021

In the report, we described the ruthenium(II)-catalyzed C–H activation/cyclization of 2-arylquinazolinones with vinyl carbonate for the synthesis of different fused quinazolinones. Through this strategy, the 6-hydroxy-5,6-dihydro-8H-isoquinolino[1,2-b]quinazolin-8-one and 8H-isoquino[1,2-b] quinazolin-8-one have been obtained, respectively, under different temperatures. Additionally, the reaction features broad substrate scope and good yields, only producing carbon dioxide as byproduct. Moreover, we performed preliminary mechanistic studies of this reaction and proposed a possible mechanism.
Evaluation of Salivary Leptin Levels and Its Correlation with Class I, Class II, and Class III Facial Skeletal Pattern: A Prefatory Study
Authors: Siva Dharma Danusha , Abu Bakar Noraini , Mustafa Basma Ezzat
Published: August 2021

Objective The aim of this study was to assess and compare the salivary leptin hormone levels between different classes of facial skeletal pattern (Class I, II, and III).

Materials and Methods A sample of 62 patients were selected prior to the orthodontic treatment from a population that attended the International Islamic University Malaysia Specialist Orthodontic Clinic. Based on the lateral cephalometric analysis, the subjects were grouped into Class I, Class II, and Class III facial skeletal patterns, according to Eastman and Wits appraisal. Subsequently, unstimulated saliva samples were taken and purified to undergo leptin enzyme-linked immunosorbent assay analysis to determine the levels of leptin hormone. Statistical analysis using the Kruskal–Wallis test was used to analyze the data obtained.

Results The results showed that there was a significant difference between the levels of leptin hormone between Class I and Class II skeletal patterns and between Class I and Class III facial skeletal patterns. No statistical difference was noted between the levels of leptin of Class II and Class III facial skeletal patterns.

Conclusion Salivary leptin hormone levels are higher in patients with Class II and Class III facial skeletal patterns compared with Class I.
Oral Health Knowledge, Attitude, and Behavior of Nursing and Technical Students in Croatia
Authors: Cabov Tomislav , Eljuga Ksenija , Fuchs Petra Nola , Devcic Maja Kinkela , Prpic Jelena , Kovac Zoran , Puharic Zrinka , Glazar Irena , Zulec Mirna
Published: August 2021

Objective The aim of this study was to test knowledge, attitudes, and behavior of the students from the Bjelovar University of Applied Sciences in relation to oral health, and to determine the respectable differences between students of nursing and technical study programs.

Materials and Methods Students were randomly selected to represent a convenient sample. A total of 140 students from nursing and technical studies were interviewed by using the World health organization Oral Health Questionnaire, adapted to fit the study purposes.

Statistical Analysis Descriptive statistics were used to determine frequency distribution and percentages for all variables. Pearson’s Chi-square test was used to compare the proportions. A p-value less than 0.05 was considered to be statistically significant.

Results The distribution of participants regarding gender was significantly different between the study programs (p = 0.000). Significant difference was also observed in their perceived socioeconomic status (p = 0.001). A significant difference was found between the study programs regarding the knowledge whether bad teeth could impair general health (p = 0.001), could tooth decay and periodontal disease may be prevented (p = 0.002), as well as the importance of regular dental check-ups for prevention of tooth decay (p = 0.028). There were significant differences regarding dietary habits and alcohol consumption in the past 30 days between the observed study programs (p = 0.000) while no significant differences were found regarding tobacco and tobacco product use (p = 0.170).

Conclusion Results obtained and presented in this paper show better knowledge and more favorable habits and behaviors among the students from nursing study program compared with the technical ones. Still all students’ habits should be changed to improve oral health. To change attitudes and influence habits, effective oral health promotion programs are needed; not only in colleges, but also in primary and secondary schools.
Evaluation and Correlation of Beta Angle with Wits Appraisal and ANB Angle in Various Skeletal Malocclusion Groups—A Cephalometric Study
Authors: Bhullar Mandeep K. , Thakur Arun K. , Mittal Sanjay , Aggarwal Isha , Palkit Tanzin , Goyal Merry
Published: August 2021

Introduction Sagittal skeletal discrepancies are frequently assessed by Wits appraisal and point A–Nasion–point B (ANB) angle. These angular and linear measurements depend upon various factors and sometime produced inaccurate results. Beta angle has been introduced recently and possesses significant advantage over ANB and Wits appraisal, because it is independent of cranial landmarks and dental occlusion.

Aim To evaluate and correlate beta angle in various skeletal malocclusions and its correlation with Wits appraisal and ANB angle.

Material and Methods The present study was carried out in Bhojia Dental College and Hospital, Baddi, Himachal Pradesh, India. A total of 63 pretreatment lateral cephalograms (23 skeletal class I, 20 skeletal class II, and 20 skeletal class III) of patients aged between 14 to 25 years were included. Various landmarks and planes were identified and marked. Values of Wits appraisal, ANB angle, and beta angle were recorded. Comparisons of group were made with the chi-square test. Spearman correlation coefficient was calculated to see relation between different values.

Results Values of correlation coefficient of beta angle with Wits appraisal and ANB angle were –0.645 and –0.815, respectively.

Conclusion Overall beta angle showed strong correlation with Wits appraisal and ANB angle, however correlation of beta angle with Wits appraisal and ANB angle among various skeletal malocclusion groups (skeletal class I, II, and III) was not statistically significant.
Impact of a Vancomycin-Induced Shift of the Gut Microbiome in a Gram-Negative Direction on Plasma Factor VIII:C Levels: Results from a Randomized Controlled Trial
Authors: Grimnes Gro , Bhoelan Soerajja , Hindberg Kristian , Davids Mark , Nieuwdorp Max , Mollnes Tom E. , Michelsen Annika E. , Ueland Thor , Brækkan Sigrid K. , Hansen John-Bjarne , Tichelaar Vladimir
Published: August 2021

Background Inflammation is present in several conditions associated with risk of venous thromboembolism. The gut microbiome might be a source of systemic inflammation and activation of coagulation, by translocation of lipopolysaccharides from gram-negative bacteria to the systemic circulation.

Objective To investigate whether a vancomycin-induced shift of the gut microbiome in a gram-negative direction influences systemic inflammation and plasma factor (F) VIII procoagulant activity (FVIII:C).

Methods and Results We performed a randomized controlled trial including 43 healthy volunteers aged 19 to 37 years. Twenty-one were randomized to 7 days of oral vancomycin intake and 22 served as controls. Feces and blood were sampled at baseline, the day after the end of intervention, and 3 weeks after intervention. Gut microbiome composition was assessed by amplicon sequencing. FVIII:C was measured using an activated partial thromboplastin time-based assay, cytokines were measured using multiplex technology, complement activation was measured using the enzyme-linked immunosorbent assay, and high-sensitivity C-reactive protein (CRP) was measured by an immunoturbidimetric assay. Vancomycin intake reduced gut microbiome diversity and increased the abundance of gram-negative bacteria. Change in FVIII:C in the intervention group was +4 IU/dL versus −6 IU/dL (p = 0.01) in the control group. A similar change was observed for log-transformed CRP (+0.21 mg/dL vs. −0.25 mg/dL, p = 0.04). The cytokines and complement activation markers remained similar in the two groups.

Conclusion The found slight increases in FVIII:C and CRP levels might support the hypothesis that a vancomycin-induced gram-negative shift in the gut microbiome could induce increased systemic inflammation and thereby a procoagulant state.
KLF11 Protects against Venous Thrombosis via Suppressing Tissue Factor Expression
Authors: Liang Wenying , Lu Haocheng , Sun Jinjian , Zhao Guizhen , Wang Huilun , Guo Yanhong , Eitzman Daniel , Chen Y Eugene , Fan Yanbo , Zhang Jifeng
Published: August 2021

Krüppel-like factors (KLFs) play essential roles in multiple biological functions, including maintaining vascular homeostasis. KLF11, a causative gene for maturity-onset diabetes of the young type 7, inhibits endothelial activation and protects against stroke. However, the role of KLF11 in venous thrombosis remains to be explored. Utilizing stasis-induced murine deep vein thrombosis (DVT) model and cultured endothelial cells (ECs), we identified an increase of KLF11 expression under prothrombotic conditions both in vivo and in vitro. The expression change of thrombosis-related genes was determined by utilizing gain- and loss-of-function approaches to alter KLF11 expression in ECs. Among these genes, KLF11 significantly downregulated tumor necrosis factor-α (TNF-α)-induced tissue factor (TF) gene transcription. Using reporter gene assay, chromatin immunoprecipitation assay, and co-immunoprecipitation, we revealed that KLF11 could reduce TNF-α-induced binding of early growth response 1 (EGR1) to TF gene promoter in ECs. In addition, we demonstrated that conventional Klf11 knockout mice were more susceptible to developing stasis-induced DVT. These results suggest that under prothrombotic conditions, KLF11 downregulates TF gene transcription via inhibition of EGR1 in ECs. In conclusion, KLF11 protects against venous thrombosis, constituting a potential molecular target for treating thrombosis.
Low hysteresis and enhanced figure-of-merit of pyroelectric energy conversion at compatible phase transformation
Authors: Zhang Chenbo , Zhu Zeyuan , Choi Jong Yun , Kim Jung Yun , Chen Xian
Published: August 2021

The pyroelectricity of polar materials provides great potential for electricity generation from waste heat. The pyroelectric effect of the material can be magnificently enhanced at a first-order phase transformation due to the abrupt jump in spontaneous polarization within a narrow temperature range. Here, we show that the performance of energy conversion by phase transformation is inversely resonant with the hysteresis of thermally driven structural transformations in a (Ba1−xSrx) (Hf0.02Ce0.005Ti0.975)O3 system, corresponding to a singular lattice distortion mode satisfying the crystallographic compatibility condition. Among the finely tuned Sr compositions from 0.04 to 0.10, we discovered that Sr0.07 composition is a promising material candidate in this material system for pyroelectric energy conversion. Our work suggests a rational strategy of material development for pyroelectric energy conversion applications.
Excitation of helical shape argon atmospheric pressure plasma jet using RF pulse modulation
Authors: Mahreen  , Veda Prakash G. , Kar Satyananda , Sahu Debaprasad , Ganguli A.
Published: August 2021

The article reports the excitation of a helical argon atmospheric pressure plasma jet using a pulse-modulated 13.56 MHz radio frequency (RF) power source. This helical structure is observed in open ambient air, which is far different from the conventional conical shape. This helical structure originates due to the periodic pressure variation in the discharge region caused by pulse-modulated RF (2 kHz modulation frequency) and propagates downstream into the ambient air. The geometrical characteristics of the observed structure are explored using optical imaging. Moreover, the influence of various input parameters, viz., duty cycle, gas flow rate, and RF power, of the modulated pulse on the formation of a helical structure are studied. These helical structures have an implication on the plasma jet chemical features (enhancement of reactive oxygen and nitrogen species) as these are involved in an increase in air entrainment into the ionization region desired for various plasma applications.
Wavelength and power dependence on multilevel behavior of phase change materials
Authors: Sevison Gary A. , Burrow Joshua A. , Guo Haiyun , Sarangan Andrew , Hendrickson Joshua R. , Agha Imad
Published: August 2021

We experimentally probe the multilevel response of GeTe, Ge2Sb2Te5 (GST), and 4% tungsten-doped GST (W-GST) phase change materials (PCMs) using two wavelengths of light: 1550 nm, which is useful for telecom-applications, and near-infrared 780 nm, which is a standard wavelength for many experiments in atomic and molecular physics. We find that the materials behave differently with the excitation at the different wavelengths and identify useful applications for each material and wavelength. We discuss thickness variation in the thin films used as well and comment on the interaction of the interface between the material and the substrate with regard to the multilevel behavior. Due to the differences in penetration depths, absorption, and index contrast, different PCMs could be more suitably used depending on the application and wavelength of operation.
Arrhenius behavior of crystallization at up to 184 000 K/s in Ge2Sb2Te5 thin films
Authors: Nozard Hantz , Schiettekatte François
Published: August 2021

We investigate the glass transition and crystallization of Ge2Sb2Te5 by nanocalorimetry on 32–57 nm layers at temperature scanning rates ranging from 23 to 184 kK/s. Crystallization follows the Arrhenius behavior observed at low heating rates, with an activation energy of 2.7 ± 0.1 eV. The crystal-growth velocity (>500 µm/s at 500 K) confirms fast values found in earlier work and by ab initio molecular dynamics simulations. These experiments also outline the importance of carrying out ultra-fast scanning calorimetry studies with samples in excellent thermal contact with the heating device.