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Quantitative phase imaging through an ultra-thin lensless fiber endoscope

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Light(Science & Applications) 2022年第8期11卷 1843-1852页

作者： Jiawei Sun Jiachen Wu Song Wu Ruchi Goswami Salvatore Girardo Liangcai Cao Jochen Guck nektarios koukourakis Juergen W.Czarske Laboratory of Measurement and Sensor System Technique(MST) TU DresdenHelmholtzstrasse 1801069DresdenGermany Competence Center for Biomedical Computational Laser Systems(BIOLAS) TU DresdenDresdenGermany State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentsTsinghua University100084BeijingChina Institute for Integrative Nanosciences IFW DresdenHelmholtzstraße 2001069DresdenGermany Max Planck Institute for the Science of Light&Max-Planck-Zentrum für Physik und Medizin 91058ErlangenGermany Cluster of Excellence Physics of Life TU DresdenDresdenGermany Institute of Applied Physics TU DresdenDresdenGermany

Quantitative phase imaging(QPI)is a label-free technique providing both morphology and quantitative biophysical information in ***,applying such a powerful technique to in vivo pathological diagnosis remains ***-core fiber bundles(MCFs)enable ultra-thin probes for in vivo imaging,but current MCF imaging techniques are limited to amplitude imaging *** demonstrate a computational lensless microendoscope that uses an ultra-thin bare MCF to perform quantitative phase imaging with microscale lateral resolution and nanoscale axial sensitivity of the optical path *** incident complex light field at the measurement side is precisely reconstructed from the far-field speckle pattern at the detection side,enabling digital refocusing in a multi-layer sample without any mechanical *** accuracy of the quantitative phase reconstruction is validated by imaging the phase target and hydrogel beads through the *** the proposed imaging modality,three-dimensional imaging of human cancer cells is achieved through the ultra-thin fiber endoscope,promising widespread clinical applications.

关键词： fiber phase thin

Investigation of human organoid retina with digital holographic transmission matrix measurements

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Light(Advanced Manufacturing) 2022年第2期3卷 33-47页

作者： nektarios koukourakis Felix Wagner Stefan Rothe Mike O.Karl Jürgen W.Czarske Laboratory for Measurement and Sensorsystem Technique TU DresdenDresdenGermany Competence Center for Biomedical Laser Systems(BIOLAS) TU DresdenDresdenGermany Center for Regenerative Therapies Dresden(CRTD) TU DresdenDresdenGermany German Center for Neurodegenerative Diseases(DZNE)Dresden DresdenGermany Faculty of Physics TU DresdenDresdenGermany Excellence Cluster Physics of Life(PoL) TU DresdenDresdenGermany

Advanced manufacturing of retinal organoid samples from human induced pluripotent stem cells represents a promising way to study the development of retinal *** retina is an epithelium composed of different cell layers with unique optical properties and detects light by photoreceptor neurons for visual *** are still many challenges in detecting early and distinct cellular changes in retinal *** this paper,we study the capability of the optical transmission matrix,which fully describes the transition of a light field propagating through a scattering *** its rich information content,the transmission matrix is commonly just used for light delivery through scattering *** holography is employed to measure the complex light-field information of the transmitted *** demonstrate that singular value decomposition of the transmission matrix allows to discriminate phantom tissues with varying scattering *** apply these findings to retinal organoid *** of the protonophore carbonyl cyanide m-chloro-phenylhydrazone(CCCP),a known inducer of retinal damage in animals,caused cell death and structural changes in human retinal organoids,which resulted in distinct changes in the transmission *** data indicate that the analysis of the transmission matrix can distinguish pathologic changes of the retina towards the development of imaging-based biomarkers.

关键词： Transmission matrix Digital holography Retina Organoids Neurodegeneration Cell death

Neighborhood environment,physical activity,and quality of life in adults:Intermediary effects of personal and psychosocial factors

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Journal of Sport and Health Science 2017年第1期6卷 96-102页

作者： Eleni Theodoropoulou nektarios A.M.Stavrou Konstantinos Karteroliotis School of Physical Education and Sport Science National and Kapodistrian University of AthensAthens 17237Greece

Background: Studies have indicated that there is a positive and indirect relationship between physical activity(PA) and quality of life(QoL). The current study examined this relationship through a social cognitive model with consideration to the intermediary effects of exercise self-efficacy,and physical(PCS, physical component summary) and psychological(MCS, mental component summary) health. Additionally, this model was widened to include concepts from the ecological theory, and any causal associations among neighborhood environment, PA, and ***: Six hundred and eighty-four physically active adults(39.16 ± 13.52 years, mean ± SD), living in Athens, Greece, completed a series of questionnaires measuring PA, QoL, exercise self-efficacy, PCS, MCS, neighborhood environment, and family and friend support for PA. The examined models were analyzed using structural equation ***: The social cognitive and ecological models proved to be of appropriate fit. Within the social cognitive model, PA positively affected QoL through the mediating effects of exercise self-efficacy, PCS, and MCS. With regards to the ecological model, neighborhood environment positively influenced QoL through the intermediary effects of family support for PA, exercise self-efficacy, PA, PCS, and ***: Results indicated that the most important mediators in the examined models were exercise self-efficacy and health. Further, findings demonstrated the role of neighborhood environment in enhancing PA and QoL. Future studies should be carried out applying longitudinal data for a better understanding of these associations over time.

关键词： Cognitive Ecological Health Self-efficacy Structural equation modeling

Training on LSA lifeboat operation using Mixed Reality

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Virtual Reality & Intelligent Hardware 2023年第3期5卷 201-212页

作者： Spyridon nektarios BOLIERAKIS Margarita KOSTOVASILI Lazaros KARAGIANNIDIS Angelos AMDITIS I-SENSE Group National Technical University of Athens(NTUA)Zografou 15773Greece

Background This work aims to provide an overview of the Mixed Reality(MR)technology’s use in maritime industry for training *** training procedures cover a broad range of procedural operations for Life-Saving Appliances(LSA)lifeboats;however,several gaps and limitations have been identified related to the practical training that can be addressed through the use of ***,Virtual and Mixed Reality applications are already used in various fields in maritime industry,but their full potential have not been yet *** project aims to exploit MR advantages in the maritime training by introducing a relevant application focusing on use and maintenance of LSA *** An MR Training application is proposed supporting the training of crew members in equipment usage and operation,as well as in maintenance activities and *** application consists of the training tool that trains crew members on handling lifeboats,the training evaluation tool that allows trainers to assess the performance of trainees,and the maintenance tool that supports crew members to perform maintenance activities and procedures on *** each tool,an indicative session and scenario workflow are implemented,along with the main supported interactions of the trainee with the *** The application has been tested and validated both in lab environment and using a real LSA lifeboat,resulting to improved experience for the users that provided feedback and recommendations for further *** application has also been demonstrated onboard a cruise ship,showcasing the supported functionalities to relevant stakeholders that recognized the added value of the application and suggested potential future exploitation *** The MR Training application has been evaluated as very promising in providing a user-friendly training environment that can support crew members in LSA lifeboat operation and maintenance,while it is still subject to

关键词： Augmented Reality Mixed Reality Maritime training Cruise industry Lifeboat operation Lifeboat maintenance H2020 research project

Impact of travel speed on the microstructure and mechanical properties of adjustable-gap bobbin-tool friction stir welded Al–Mg joints

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International Journal of Minerals,Metallurgy and Materials 2021年第4期28卷 710-717页

作者： Dong Wu Wen-ya Li Yan-jun Gao Jun Yang Quan Wen nektarios Vidakis Achillefs Vairis State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Travel TechnologiesNorthwestern Polytechnical UniversityXi'an 710072China Capital Aerospace Machinery Company Beijing 100076China Department of Mechanical Engineering Hellenic Mediterranean UniversityHeraklionCrete 71004Greece

The butt welds of 4-mm thick 5A06 aluminum alloy plates were produced by adjustable-gap bobbin-tool friction stir travel with travel speeds of 200, 300, and 400 mm/min in this *** microstructure was studied using optical microscopy and electron backscatter diffraction(EBSD).Tensile tests and microhardness measurements were performed to identify the effect of the travel speed on the joint mechanical *** joints were obtained at 200 mm/min while voids were present at different positions of the joints as the travel speed *** EBSD results show that the grain size, high angle grain boundaries, and density of geometrically necessary dislocations in different regions of the joint vary depending on the recovery and recrystallization *** attention was given to the relationship between the local microstructure and mechanical *** measurements show that the average hardness of the stir zone(SZ) was greater than that of the base material, which was only affected slightly by the travel *** tensile strength of the joint decreased with increasing travel speed and the maximal strength efficiency reached 99%.

关键词： friction stir welding bobbin-tool aluminum alloy microstructure mechanical properties adjustable-gap

Impact of 0.1% sodium hyaluronate and 0.2% sodium hyaluronate artificial tears on postoperative discomfort following cataract extraction surgery: a comparative study

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Eye and Vision 2019年第1期6卷 41-49页

作者： Panagiota Ntonti Eirini-Kanella Panagiotopoulou Georgios Karastatiras nektarios Breyannis Sevasti Tsironi Georgios Labiris Department of Ophthalmology University Hospital of Alexandroupolis68100 DraganaAlexandroupolisGreece Department of Ophthalmology Papanikolaou General HospitalThessalonikiGreece Department of Ophthalmology Naval Hospital of AthensAthensGreece Department of Ophthalmology Athinaiki KlinikiAthensGreece

Background:Recent artificial tear preparations have provided 0.2%concentration of sodium ***,no published data exist on their potential superiority against 0.1%in alleviating dry-eye-disease symptoms in cataract extraction ***:A total of 180 patients that underwent cataract extraction surgery were randomly divided into 2 groups according to their postoperative regime:Study group(SG)received fixed combination of tobramycin and dexamethasone(FCTD)quid for 3 weeks,and additionally 0.2%sodium hyaluronate provided in the COMOD®device quid for 6 *** group(CG)received fixed combination of tobramycin and dexamethasone(FCTD)quid for 3 weeks,and additionally 0.1%sodium hyaluronate provided in the COMOD®device quid for 6 *** following indexes were evaluated at 3 postoperative checkpoints:(1)Surface discomfort index(SDI)which was derived by four direct 10-scale Likert-type questions that were addressed to the patient and pertained to:(a)foreign body sensation(FBS),(b)blinking discomfort(BD),(c)stinging sensation(SS),(d)tearing sensation(TS),(2)Tear breakup time(TBUT),(3)Schirmer’s test,(4)Central corneal thickness(CCT),and (4)Central Corneal Sensitivity(CCS).Results:Both groups showed reduced CCS values at all postoperative examination points;however,SG participants had significantly better CCS(all p<0.05).SG had better TBUT than CG at the 3rd(p=0.03)and 6th examination points(p=0.04).Moreover,SG had better SDI scores at the 3rd(SDI=9.26±0.55)and 6th weeks(SDI=9.47±0.48)*** participants(p=0.03 and p<0.01,respectively).Conclusion:The increased 0.2%sodium hyaluronate concentration in the artificial tears provided in the COMOD®device seems to address dry-eye-disease symptoms better in patients who underwent phacoemulsification surgery than the 0.1%*** registration:*** Identifier:NCT03705949 Oct 15,2018,retrospectively registered.

关键词： Cataract Postoperative regime Artificial tears Surface discomfort index Hylocomod Hylogel Sodium hyaluronate

Multifunctional HDPE/Cu biocidal nanocomposites for MEX additive manufactured parts: Perspectives for the defense industry

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Defence Technology（防务技术） 2024年第8期38卷 16-32页

作者： Nectarios Vidakis Nikolaos Michailidis Markos Petousis nektarios K.Nasikas Vassilios Saltas Vassilis Papadakis Nikolaos Mountakis Apostolos Argyros Mariza Spiridaki Ioannis Valsamos Department of Mechanical Engineering Hellenic Mediterranean UniversityHeraklion 71410Greece Physical Metallurgy Laboratory Mechanical Engineering DepartmentSchool of EngineeringAristotle University of ThessalonikiThessaloniki 54124Greece Centre for Research&Development of Advanced Materials(CERDAM) Center for Interdisciplinary Research and InnovationBalkan CentreThessaloniki 57001Greece Division of Mathematics and Engineering Sciences Department of Military SciencesHellenic Army AcademyVari GR16673AtticaGreece Department of Electronic Engineering Hellenic Mediterranean UniversityChania 73133Greece Department of Industrial Design and Production Engineering University of West AtticaAthens 12244Greece Institute of Electronic Structure and Laser Foundation for Research and Technology-HellasHeraklion 70013Greece

In this study, we investigated the performance improvement caused by the addition of copper(Cu)nanoparticles to high-density polyethylene(HDPE) matrix material. Composite materials, with filler percentages of 0.0, 2.0, 4.0, 6.0, 8.0, and 10.0 wt% were synthesized through the material extrusion(MEX)3D printing technique. The synthesized nanocomposite filaments were utilized for the manufacturing of specimens suitable for the experimental procedure that followed. Hence, we were able to systematically investigate their tensile, flexural, impact, and microhardness properties through various mechanical tests that were conducted according to the corresponding standards. Broadband Dielectric Spectroscopy was used to investigate the electrical/dielectric properties of the composites. Moreover, by employing means of Raman spectroscopy and thermogravimetric analysis(TGA) we were also able to further investigate their vibrational, structural, and thermal properties. Concomitantly, means of scanning electron microscopy(SEM), as well as atomic force microscopy(AFM), were used for the examination of the morphological and structural characteristics of the synthesized specimens, while energy-dispersive Xray spectroscopy(EDS) was also performed in order to receive a more detailed picture on the structural characteristics of the various synthesized composites. The corresponding nanomaterials were also assessed for their antibacterial properties regarding Staphylococcus aureus(S. aureus) and Escherichia coli(E. coli) with the assistance of a method named screening agar well diffusion. The results showed that the mechanical properties of HDPE benefited from the utilization of Cu as a filler, as they showed a notable improvement. The specimen of HDPE/Cu 4.0 wt% was the one that presented the highest levels of reinforcement in four out of the seven tested mechanical properties(for example, it exhibited a 36.7%improvement in the flexural strength, compared to the pure matrix). At the same

关键词： High-density polyethylene(HDPE) Copper(Cu) Material extrusion(MEX) Mechanical performance Electrical properties Antibacterial Defense and security

No treeline shift despite climate change over the last 70 years

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Forest Ecosystems 2022年第1期9卷 13-22页

作者： Mirela Beloiu Dimitris Poursanidis Antonis Tsakirakis nektarios Chrysoulakis Samuel Hoffmann Petros Lymberakis Antonis Barnias David Kienle Carl Beierkuhnlein Department of Biogeography University of BayreuthUniversitatsstraaße 3095447BayreuthGermany Remote Sensing Lab Institute of Applied and Computational MathematicsFoundation for Research and Technology Hellas100 N.Plastira Str.Vassilika VoutonHeraklion70013Greece Samaria National Park Management BodyOld National Road Chanion-KissamouAgioi ApostoloiChaniaCreteGreece Natural History Museum of Crete University of CreteKnossou Av.71409IrakleioCreteGreece GIB Department of Geography University of Bayreuth95447BayreuthGermany BayCEER Bayreuth Center of Ecology and Environmental Research University of Bayreuth95448BayreuthGermany

Background:The recent rise in temperature and shifting precipitation regimes threaten ecosystems around the globe to different *** are expected to respond to climate warming by shifting to higher elevations,but it is unclear whether they can track temperature ***,we integrated high-resolution aerial imagery with local climatic and topographic characteristics to study the treeline dynamic from 1945 to 2015 on the semiarid Mediterranean island of Crete,***:During the study period,the mean annual temperature at the treeline increased by 0.81℃,while the average precipitation decreased by 170 *** treeline is characterized by a diffuse form,with trees growing on steep limestone slopes(>50°)and shallow ***,the treeline elevation decreases with increasing distance from the coast and with aspect(south>north).Yet,we found no shift in the treeline over the past 70 years,despite an increase in temperature in all four study ***,the treeline elevation correlated strongly with topographic exposure to wind(R^(2)=0.74,p<0.001).Therefore,the temporal lag in treeline response to warming could be explained by a combination of topographic and microclimatic factors,such as the absence of a shelter effect and a decrease in ***:Although there was no treeline shift over the last 70 years,climate change has already started shifting the treeline altitudinal ***,the lack of climate-mediated migration at the treeline should raise concerns about the threats posed by warming,such as drought damages,and wildfire,especially in the Mediterranean ***,conservation management should discuss options and needs to support adaptive management.

关键词： Aerial imagery Protected area Continental island Mediterranean region High mountains Temperature Precipitation Climate change Forest dynamics

Alzheimer Disease and Music-Therapy: An Interesting Therapeutic Challenge and Proposal

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Advances in Alzheimer's Disease 2021年第1期10卷 1-18页

作者： Aligizakis Eftychios Sivaropoulos nektarios Gryllaki Nikoleta Public Health Center of Kandanos Chania Greece Public Health Center of Spili Rethymno Greece Public Health Center of Chania Chania Greece

Aim: The aim of this study is to highlight the effectiveness of music therapy in Alzheimer’s Disease (AD) and their caregivers. Methods: The biennial 2019 to 2020, 32 patients, with AD (ICD-10), were examined, by a research group composed by a Neurologist, a GP and a Music-psychotherapist. All patients were under pharmaceutical care. The patients’ medical record and musical profile was assessed. The answers were provided by the patients themselves or by their tutors. Then, personal or family sessions were organized with the participation of musical instruments. The patients staging and evaluation were made through MMSE. The test was repeated every six months under the Neurologist’s supervision. Finally, 31 totally patients succeeded to complete our intervention and to be estimated. Results: The duration of follow-up of the patients was 30 months. At the beginning and end of the sessions we obtained the following data: In a total of 32 patients with AD, initially 3 patients (9.37%) had Mild AD, 19 patients (59.37%) had Moderate AD, 10 patients (31.25%) severe AD, based on the MMSE evaluation. After 30 months, 11 patients had Mild AD (35.48%), number resulting from the music benefit of cognitive function in patients with moderate AD. 15 patients with Moderate AD (48.38%) were observed, out of the initial 19 (59.37%) patients with Moderate AD, a number attributed to the sum of patients who improved from severe AD and those who were transferred, benefiting from treatment, from Moderate AD disease to Mild AD. Finally 5 patients with severe AD disease were evaluated (16.12%), while before the treatment we had 10 patients (31.25%) with severe AD. Conclusions: Music therapy is a tool to increase the life quality of the participants. The results expected in the treatment of AD are obtained by means of good collaboration among the research team.

关键词： Alzheimer Disease Patients Care Givers Music-Therapy Improvement of Cognitive Impairment