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Nonlinearity-tailored fiber laser technology for low-noise, ultra-wideband tunable femtosecond light generation

Photonics Research 2017年第6期5卷 262-273页

作者： XIAOMIN LIU JESPER LAEGSGAARD ROMAN IEGOROV ASK S.SVANE f.omer ilday HAOHUA TU STEPHEN A.BOPPART DMITRY TURCHINOVICH DTU fotonik Technical University of Denmark Max Planck Institute for Polymer Research Department of Physics Bilkent University National Research Tomsk Polytechnic University Institute of Power Engineering Department of Electrical and Electronics Engineering Bilkent University Biophotonics Imaging Laboratory University of Illinois at Urbana-Champaign fakultat fur Physik Universitat Duisburg-Essen

The emission wavelength of a laser is physically predetermined by the gain medium used. Consequently, arbitrary wavelength generation is a fundamental challenge in the science of light. Present solutions include optical parametric generation, requiring complex optical setups and spectrally sliced supercontinuum, taking advantage of a simpler fiber technology: a fixed-wavelength pump laser pulse is converted into a spectrally very broadband output, from which the required resulting wavelength is then optically filtered. Unfortunately, this process is associated with an inherently poor noise figure, which often precludes many realistic applications of such supercontinuum sources. Here, we show that by adding only one passive optical element—a tapered photonic crystal fiber—to a fixed-wavelength femtosecond laser, one can in a very simple manner resonantly convert the laser emission wavelength into an ultra-wide and continuous range of desired wavelengths, with very low inherent noise, and without mechanical realignment of the laser. This is achieved by exploiting the double interplay of nonlinearity and chirp in the laser source and chirp and phase matching in the tapered fiber. As a first demonstration of this simple and inexpensive technology, we present a femtosecond fiber laser continuously tunable across the entire red–green–blue spectral range.

关键词： length PCf Nonlinearity-tailored fiber laser technology for low-noise ultra-wideband tunable femtosecond light generation

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Mechanism of adjusting bypass ratio by front variable area bypass injector for a variable cycle engine

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Chinese Journal of Aeronautics 2024年第10期37卷 158-171页

作者： Qian LI Chen XIA Guoping HUANG omer MUSA Linjun LI Zonghan YU College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China AECC Sichuan Gas Turbine Establishment Chengdu 610500China College of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

The front Variable Area Bypass Injector(fVABI)is a key to bypass ratio adjustment for a Variable Cycle Engine(VCE).In order to study the role of the fVABI with the Core Driven fan Stage(CDfS)duct,firstly,the engine bypass with the CDfS duct model and the equivalent engine bypass without the CDfS duct model are designed using the concept of a jet boundary *** comparing the difference between airflow driving forces in the two engine bypass models,the quantitative effects of the injection from the CDfS duct on the mass flow rate of the engine bypass airflow are obtained under different combinations of pressure difference and area ***,the CDfS duct injection characteristic map is obtained through the typical experiment of the *** on this map,the performance model of the fVABI is ***,the turbofan engine model with the Variable Inlet Guide Vane(VIGV),the first Variable Cycle Engine model(VCE1)with the CDfS duct and without the VIGV,and the Second Variable Cycle Engine model(VCE2)with the CDfS duct and VIGV are *** gain on the engine bypass ratio adjustment range caused by the injection from the CDfS duct is clarified by comparing the three engine *** is concluded that the bypass ratio adjustment range of the variable cycle engine with the fVABI is about twice that of the traditional turbofan engine.

关键词： front variable area bypass injector Variable cycle engine Bypass ratio Injection CDfS duct injection characteristic map

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Detecting early changes in choroidal vascularity and thickness using optical coherence tomography in patients with corneal crosslinking for keratoconus

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International Journal of Ophthalmology(English edition) 2024年第7期17卷 1267-1272页

作者： Selim Doganay Mehmet omer Kiristioglu Derya Doganay Elif Kacmaz Department of Ophthalmology Bursa Uludag University School of MedicineBursa 16059Turkey Department of Ophthalmology University of Health Sciences Bursa Yuksek Ihtisas Training and Research HospitalBursa 16310Turkey

AIM:To investigate changes in choroidal thickness and vascularity in keratoconus patients treated with corneal ***:This study evaluated 28 eyes of 22 patients with keratoconus who underwent corneal *** choroidal thicknesses were evaluated on enhanced depth imaging optical coherence tomography at the preoperative and postoperative 3d,1,and *** thickness in the four cardinal quadrants and the fovea were *** choroidal vascularity index was also ***:There was no significant difference in central choroidal thickness between the preoperative and postoperative 3d,1mo(P>0.05).There was a significant increase in the 3mo(P=0.034)and a significant decrease in the horizontal choroidal vascularity index on the postoperative 3d(P=0.014),there was no statistically significant change in vertical axes and other visits in horizontal sections(P>0.05).CONCLUSION:This study sheds light on choroidal changes in postoperative corneal crosslinking for *** it suggests the procedure’s relative safety for submacular choroid,more extensive research is necessary to confirm these findings and their clinical significance.

关键词： keratoconus corneal crosslinking choroidal vascularity index enhanced depth imaging optical coherence tomography

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Cellulolytic characterization of the rumen-isolated Acinetobacter pittii ROBY and design of a potential controlled-release drug delivery system

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Engineering Microbiology 2024年第3期4卷 22-28页

作者： Ruken Sariboga omer faruk Sarioglu Istanbul Medeniyet University Department of Molecular Biology and GeneticsIstanbul 34730Turkey Istanbul Medeniyet University Science and Advanced Technologies Research Center(BILTAM)Istanbul 34730Turkey

A novel cellulolytic bacterial strain,ROBY,was isolated from a bovine rumen sample using the enrichment cul-ture *** isolate was found to be Acinetobacter pittii,with>99%similarity according to 16S rRNA gene sequence *** potential use of this strain in combination with doxorubicin(Dox)-integrated cellulose nanoparticles(Dox-CNPs)was evaluated as a proof-of-concept study for the further development of this approach as a novel controlled-release drug delivery *** isolate can utilize CNPs as the sole carbon source for growth and degrade both Dox-CNPs and empty CNPs with high *** cellulases isolated from bacteria may also be used to trigger Dox *** results also demonstrated that the release of Dox into the environment due to nanoparticle degradation in the samples incubated with Dox-CNPs significantly affected bac-terial cell viability(∼75%decrease),proving the release of Dox due to bacterial cellulase activity and suggesting the great potential of this approach for further development.

关键词： Acinetobacter pittii Microcrystalline cellulose Cellulose nanoparticle Controlled-release drug delivery system Doxorubicin

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An integrated spatial planning of the mountainous landscapes for ski sports in a case area at the eastern Türkiye

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Journal of Mountain Science 2024年第3期21卷 754-767页

作者： SATIR Onur TOSUN Busra COSKUN OZYOL funda OZDEMIR omer faruk BERBEROGLU Suha Dept.of Landscape Architecture Van Yuzuncu Yil UniversityVan 65090Türkiye School of Physical Education&Sports Van Yuzuncu Yil UniversityVan 65090Türkiye Van Yuzuncu Yil University Dept.of Architecture&Urban Planning Van 65090Türkiye Dept.of Remote Sensing&GIS Cukurova UniversityAdana 01330Türkiye

Mountainous regions have disadvantages in economic development because of harsh physical and climatic ***,winter tourism activities are one of the key components for supporting economic development in the *** a ski resort area supports direct and indirect employment in a region,and it stops immigration from mountainous regions to other *** research aimed to assess the potential ski areas using a multi criteria evaluation technique in the Van region which is located in the eastern part of Tü*** this context,snow cover duration,sun effect,slope,slope length,elevation,population density,distance from main roads and lake visibility were used as input factors in the decision making *** factor was standardized using a fuzzy technique based on existing well-known ski centers in Tü*** weight of inputs was defined by applying a survey to the professional *** most important factors were detected as transportation opportunities and snow covers whereas,the least important factors were elevation and population ***,lake visibility was very important to make a difference from other existing facilities in the ***,it was included as constraints and lake visible areas were extracted at the final stage of the *** ski areas were mapped in three levels as professional,intermediate and beginner *** of the suitable areas was selected as a sample projection and for the 3D simulation of the ski investment *** costs and benefits were *** was found that a ski tourism area investment can be amortized in 3 years in the region.

关键词： Winter sports and tourism Decision making 3D simulation and modelling Landscape planning GIS

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Elevating Image Steganography:A fusion of MSB Matching and LSB Substitution for Enhanced Concealment Capabilities

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Computers, Materials & Continua 2024年第5期79卷 2923-2943页

作者： Muhammad Zaman Ali omer Riaz Hafiz Muhammad Hasnain Waqas Sharif Tenvir Ali Gyu Sang Choi Department of Information Technology The Islamia University of BahawalpurBahawalpur63100Pakistan Department of Computer Science The Islamia University of BahawalpurBahawalpur63100Pakistan School of Computer Science and Engineering Yeungnam UniversityGyeongbuk38541Korea

In today’s rapidly evolving landscape of communication technologies,ensuring the secure delivery of sensitive data has become an essential *** overcome these difficulties,different steganography and data encryption methods have been proposed by researchers to secure *** of the proposed steganography techniques achieve higher embedding capacities without compromising visual imperceptibility using LSB *** this work,we have an approach that utilizes a combinationofMost SignificantBit(MSB)matching andLeast Significant Bit(LSB)*** proposed algorithm divides confidential messages into pairs of bits and connects them with the MSBs of individual pixels using pair matching,enabling the storage of 6 bits in one pixel by modifying a maximum of three *** proposed technique is evaluated using embedding capacity and Peak Signal-to-Noise Ratio(PSNR)score,we compared our work with the Zakariya scheme the results showed a significant increase in data concealment *** achieved results of ourwork showthat our algorithmdemonstrates an improvement in hiding capacity from11%to 22%for different data samples while maintaining a minimumPeak Signal-to-Noise Ratio(PSNR)of 37 *** findings highlight the effectiveness and trustworthiness of the proposed algorithm in securing the communication process and maintaining visual integrity.

关键词： Steganography most significant bit(MSB) least significant bit(LSB) peak signal-to-noise ratio(PSNR)

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Image Classification Based on Vision Transformer

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Journal of Computer and Communications 2024年第4期12卷 49-59页

作者： Attiapo Acybah Morel omer Department of Computer Science Hubei University of Technology Wuhan China

This research introduces an innovative approach to image classification, by making use of Vision Transformer (ViT) architecture. In fact, Vision Transformers (ViT) have emerged as a promising option for convolutional neural networks (CNN) for image analysis tasks, offering scalability and improved performance. Vision transformer ViT models are able to capture global dependencies and link among elements of images. This leads to the enhancement of feature representation. When the ViT model is trained on different models, it demonstrates strong classification capabilities across different image categories. The ViT’s ability to process image patches directly, without relying on spatial hierarchies, streamlines the classification process and improves computational efficiency. In this research, we present a Python implementation using Tensorflow to employ the (ViT) model for image classification. four categories of animals such as (cow, dog, horse and sheep) images will be used for classification. The (ViT) model is used to extract meaningful features from images, and a classification head is added to predict the class labels. The model is trained on the CIfAR-10 dataset and evaluated for accuracy and performance. The findings from this study will not only demonstrate the effectiveness of the Vision Transformer model in image classification tasks but also its potential as a powerful tool for solving complex visual recognition problems. This research fills existing gaps in knowledge by introducing a novel approach that challenges traditional convolutional neural networks (CNNs) in the field of computer vision. While CNNs have been the dominant architecture for image classification tasks, they have limitations in capturing long-range dependencies in image data and require hand-designed hierarchical feature extraction.

关键词： Convolutional Neural Networks ViT CNN Deep Learning Architecture

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How has the COVID-19 pandemic changed treatment preferences of patients with proximal ureteral stones?

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当代泌尿学（英文） 2024年第1期18卷 66-70页

作者： Ali Kaan Yildiz Ahmet Varan Hakan Kurt omer Gokhan Doluoglu Berat Cem Ozgur Department of Urology University of Medical SciencesAnkara Training and Research HospitalAnkaraTurkey

Background:The impact of the coronavirus disease 2019(COVID-19)pandemic on patient decision making remains *** study aimed to investigate the effect of the pandemic on treatment preferences of patients with proximal ureteral stones.Materials and methods:Retrospective data regarding treatment preferences of patients diagnosed with symptomatic proximal ure-teral stones between July 2018 and November 2021 at a single center were *** from 493 patients were analyzed according to 2 groups,including patients diagnosed during the COVID-19 pandemic and those diagnosed during an equivalent period of time be-fore the pandemic.Results:Preference for conservative treatment increased during the COVID-19 pandemic(p=0.009).In patients who had previously undergone shock wave lithotripsy(SWL),the preference for SWL decreased and the preference for conservative treatment increased during the COVID-19 pandemic(p=0.042).Multiple logistic regression analysis revealed a significant correlation between a preference for conservative treatment during the pandemic and no prior spontaneous stone passage(p=0.003;odds ratio[OR],2.48;95％con-fidence interval[CI],1.45-4.23),no hydronephrosis(p=0.035;OR,3.57;95％Cl,1.34-9.49),and a visual analog scale score of 4 or less(p=0.018;OR,1.97;95％Cl,1.15-3.38).Conclusions:A significant increase in the preference for conservative treatment was observed among patients diagnosed during the pandemic,and patients with a history of SWL demonstrated a preference shift from SWL to conservative treatment.

关键词： COVID-19 pandemic Treatment preference Ureter Urolithiasis

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Allogeneic mesenchymal stem cells may be a viable treatment modality in cerebral palsy

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World Journal of Clinical Cases 2024年第9期12卷 1585-1596页

作者： Osman Boyalı Serdar Kabatas ErdinçCivelek omer Ozdemir Yeliz Bahar-Ozdemir Necati Kaplan Eyüp Can Savrunlu Erdal Karaöz Department of Neurosurgery University of Health Sciences TurkeyGaziosmanpaşa Training and Research HospitalIstanbul 34360Turkey Center for Stem Cell&Gene Therapy Research and Practice University of Health Sciences TurkeyIstanbul 34360Turkey Department of Physical Medicine and Rehabilitation Health Sciences University Sultan Abdulhamid Han Training and Research HospitalIstanbul 34668Turkey Department of Neurosurgery Istanbul Rumeli UniversityÇorlu Reyap HospitalTekirdağ59860Turkey Department of Neurosurgery Nevşehir State HospitalNevşehir 50300Turkey Center for Regenerative Medicine and Stem Cell Research&Manufacturing(LivMedCell) Liv HospitalIstanbul 34340Turkey Department of Histology and Embryology Istinye UniversityFaculty of Medicineİstanbul 34010Turkey Center for Stem Cell and Tissue Engineering Research and Practice Istinye UniversityIstanbul 34340Turkey

BACKGROUND Cerebral palsy(CP)describes a group of disorders affecting movement,balance,and *** in motor functions constitute the main body of CP *** symptoms surface in early childhood and patients are affected for the rest of their ***,treatment involves various pharmacotherapies for different types of CP,including antiepileptics for epilepsy and Botox A for focal ***,none of these methods can provide full symptom *** has prompted researchers to look for new treatment modalities,one of which is mesenchymal stem cell therapy(MSCT).Despite being a promising tool and offering a wide array of possibilities,mesenchymal stem cells(MSCs)still need to be investigated for their efficacy and *** To analyze the efficacy and safety of MSCT in CP *** Our sample consists of four CP patients who cannot stand or walk without external *** of these cases received allogeneic MSCT six times as 1×106/kg intrathecally,intravenously,and intramuscularly using umbilical cord-derived MSCs(UC-MSC).We monitored and assessed the patients pre-and post-treatment using the Wee functional Independence Measure(WeefIM),Gross Motor function Classification System(GMfCS),and Manual Ability Classification Scale(MACS)*** utilized the Modified Ashworth Scale(MAS)to measure *** We found significant improvements in MAS scores after the intervention on both *** months:Rightχ^(2)=4000,P=0.046,leftχ^(2)=4000,P=0.046;four months:Rightχ^(2)=4000,P=0.046,leftχ^(2)=4000,P=0.046;12 months:Rightχ^(2)=4000,P=0.046,leftχ^(2)=4000,P=***,there was no significant difference in motor functions based on WeefIM results(P>0.05).GMfCS and MACS scores differed significantly at 12 months after the intervention(P=0.046,P=0.046).finally,there was no significant change in cognitive functions(P>0.05).CONCLUSION In light of our findings,we believe that UC-MSC therapy has a positive effect on spasticity

关键词： Cerebral palsy Mesenchymal stem cell Transplantation Wharton’s jelly Muscle spasticity

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Safety and efficiency of Wharton’s Jelly-derived mesenchymal stem cell administration in patients with traumatic brain injury:first results of a phase I study

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World Journal of Stem Cells 2024年第6期16卷 641-655页

作者： Serdar Kabatas ErdinçCivelek Osman Boyalı Gülseli Berivan Sezen omer Ozdemir Yeliz Bahar-Ozdemir Necati Kaplan Eyüp Can Savrunlu Erdal Karaöz Department of Neurosurgery University of Health Sciences TurkeyGaziosmanpaşa Training and Research HospitalIstanbul 34360Türkiye Center for Stem Cell&Gene Therapy Research and Practice University of Health Sciences TurkeyIstanbul 34255Türkiye Department of Neurosurgery University of Health SciencesGaziosmanpaşa Training and Research HospitalIstanbul 34255Türkiye Department of Physical Medicine and Rehabilitation Health Sciences University Sultan Abdulhamid Han Training and Research HospitalIstanbul 34668Türkiye Department of Neurosurgery Istanbul Rumeli UniversityÇorlu Reyap HospitalTekirdağ59860Türkiye Department of Neurosurgery Nevşehir State HospitalNevşehir 50300Türkiye Center for Regenerative Medicine and Stem Cell Research&Manufacturing(LivMedCell) Liv HospitalIstanbul 34340Türkiye Department of Histology and Embryology Istinye UniversityFaculty of MedicineIstanbul 34010Türkiye Center for Stem Cell and Tissue Engineering Research and Practice Istinye UniversityIstanbul 34340Türkiye

BACKGROUND Traumatic brain injury(TBI)is characterized by a disruption in the normal function of the brain due to an injury following a trauma,which can potentially cause severe physical,cognitive,and emotional *** cell transplantation has evolved as a novel treatment modality in the management of TBI,as it has the potential to arrest the degeneration and promote regeneration of new cells in the ***’s Jelly-derived mesenchymal stem cells(WJ-MSCs)have recently shown beneficial effects in the functional recovery of neurological *** To evaluate the safety and efficiency of MSC therapy in *** We present 6 patients,4 male and 2 female aged between 21 and 27 years who suffered a *** 6 patients underwent 6 doses of intrathecal,intramuscular(i.m.)and intravenous transplantation of WJ-MSCs at a target dose of 1×106/kg for each application *** was assessed using the Modified Ashworth scale(MAS),motor function according to the Medical Research Council Muscle Strength Scale,quality of life was assessed by the functional Independence Measure(fIM)scale and Karnofsky Performance Status *** Our patients showed only early,transient complications,such as subfebrile fever,mild headache,and muscle pain due to ***,which resolved within 24 *** the one year follow-up,no other safety issues or adverse events were *** 6 patients showed improvements in their cognitive abilities,muscle spasticity,muscle strength,performance scores and fine motor skills when compared before and after the *** values,which we used to assess spasticity,were observed to statistically significantly decrease for both left and right sides(PfIM scale includes both motor scores(Pficant increase in pretest posttest *** difference observed in the participants’Karnofsky Performance Scale values pre and post the intervention was statistically si

关键词： Traumatic brain injury Wharton Jelly Stem cell therapy Transplantation Mesenchymal stem cell

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