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Effects of oral contrast on dose in abdominopelvic computed tomography with pure iterative reconstruction

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World Journal of Radiology 2016年第9期8卷 809-815页

作者： kevin p murphy Liam J Healy Lee Crush Maria Twomey Fiachra Moloney Sylvia Sexton Owen J O'Connor Michael M Maher Department of Radiology Cork University Hospital

AIM To assess the effect of neutral(NC) and positive(pC) oral contrast use on patient dose in low-dose abdominal computed tomography(CT).METHODS Low-dose clinically indicated CTs were performed on 79 Crohn's patients(35 = pC, 1 L 2% gastrografin; 44 = NC, 1.5 L polyethylene glycol). Scanner settings for both acquisitions were identical apart from 25 s difference in intravenous contrast timing. Body mass index(BMI), scan-ranges, dose-length product and size-specific dose estimated were recorded. Data was reconstructed with pure model-based iterative reconstruction. Image quality was objectively and subjectively analysed. Data analysis was performed with Statistical package for Social *** Higher doses were seen in neutral contrast CTs(107.60 ± 78.7 m ***, 2.47 ± 1.21 m Gy vs 85.65 ± 58.2 m ***, 2.18 ± 0.96 m Gy). The differencehad both NC and pC investigations. Image-quality assessment yielded 6952 datapoints. NC image quality was significantly superior(p patial resolution, subjective contrast resolution, diagnostic acceptability) at all levels. NC bowel distension was significantly(p polyethylene glycol as a neutral OC agent leads to higher radiation doses than standard positive contrast studies, in low dose abdominal CT imaging. This is possibly related to the osmotic effect of the agent resulting in larger intraluminal fluid volumes and resultant increased overall beam attenuation.

关键词： Radiation dose Low dose computed tomography Abdominal imaging Oral contrast Computed tomography

Integrated photonic fractional convolution accelerator

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photonics Research 2024年第8期12卷 1828-1839页

作者： kevin ZELAYA MOHAMMED-ALI MIRI Department of physics Queens College of the City University of New YorkQueensNew York 11367USA physics program The Graduate Center of the City University of New YorkNew YorkNew York 10016USA

An integrated photonic circuit architecture to perform a modified-convolution operation based on the discrete fractional Fourier transform(DFrFT) is introduced. This is accomplished by utilizing two nonuniformly coupled waveguide lattices with equally spaced eigenmode spectra, the lengths of which are chosen so that the DFrFT and its inverse operations are achieved. A programmable modulator array is interlaced so that the required fractional convolution operation is performed. Numerical simulations demonstrate that the proposed architecture can effectively perform smoothing and edge detection tasks even for noisy input signals, which is further verified by electromagnetic wave simulations. Notably, mild lattice defects do not jeopardize the architecture performance, showing its resilience to manufacturing errors.

关键词： fractional convolution utilizing

C-reactive protein and radiographic findings of lower respiratory tract infection in infants

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World Journal of Radiology 2017年第4期9卷 206-211页

作者： Maria Twomey Hannah Fleming Fiachra Moloney kevin p murphy Lee Crush Siobhan B O’Neill Oisin Flanagan Karl James Conor Bogue Owen J O’Connor Michael M Maher Department of Radiology Cork University HospitalWiltonT12 DC4A CorkIreland

AIM To evaluate the association between C-reactive protein(CRp) and radiological evidence of lower respiratory tract infection(LRTI) in *** All patients aged less than 4 years who presented with suspected lower respiratory tract infection,who received a peri-presentation chest radiograph and CRp blood measurement over an 18-mo period were included in the ***,gender,source of referral,CRp,white cell count,neutrophil count along with the patients' symptoms and radiologist's report were *** Three hundred and eleven patients met the *** chest radiographs were more common in patients with elevated CRp levels(p phs when a patient had a CRp level between 50-99 mg/*** levels were a better predictor of positive chest radiograph findings for those aged greater than I year compared to those 1 year or *** CRp may be used in patients with suspected LRTI diagnosis to select those who are likely to have positive findings on chest radiograph,thus reducing unnecessary chest radiographs.

关键词： Chest radiograph C-reactive protein Chest infection Respiratory infection pediatric

Neurolithography:Lithography as an enabling technology in neurology and neuroscience

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Medicine in Novel Technology and Devices 2024年第2期22卷 15-18页

作者： kevin Zhai Department of Medical Education Weill Cornell Medicine-QatarP.O.Box 24144DohaQatar

Modern lithography,which enables the fabrication of complex structures in biomedical devices with exceptional precision,is a potentially transformative force in the neural *** such as photolithography,electron beam lithography,and soft lithography have been utilized to produce devices that guide neuronal growth and differentiation and measure electrophysiological signals at the single-cell *** the clinical sphere,lithography plays a role in the manufacturing of devices for deep brain stimulation,brain-computer interface,and ***,we briefly review the applications of lithography in basic and translational neuroscience and clinical neurology,with an eye toward future advancement.

关键词： Lithography Neurolithography Semiconductors Microfluidics Neural devices

An Efficient Smoothing and Thresholding Image Segmentation Framework with Weighted Anisotropic-Isotropic Total Variation

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1369-1405页

作者： kevin Bui Yifei Lou Fredrick park Jack Xin Department of Mathematics University of CaliforniaIrvineIrvineCA 92697-3875USA Department of Mathematics University of North CarolinaChapel HillChapel HillNC 27599.USA Department of Mathematics and Computer Science Whittier CollegeWhittierCA 90602USA

In this paper,we design an efficient,multi-stage image segmentation framework that incorporates a weighted difference of anisotropic and isotropic total variation(AITV).The segmentation framework generally consists of two stages:smoothing and thresholding,thus referred to as smoothing-and-thresholding(SaT).In the first stage,a smoothed image is obtained by an AITV-regularized Mumford-Shah(MS)model,which can be solved efficiently by the alternating direction method of multipliers(ADMMs)with a closed-form solution of a proximal operator of the l_(1)-αl_(2) *** convergence of the ADMM algorithm is *** the second stage,we threshold the smoothed image by K-means clustering to obtain the final segmentation *** experiments demonstrate that the proposed segmentation framework is versatile for both grayscale and color images,effcient in producing high-quality segmentation results within a few seconds,and robust to input images that are corrupted with noise,blur,or *** compare the AITV method with its original convex TV and nonconvex TVp(Opparts,showcasing the qualitative and quantitative advantages of our proposed method.

关键词： Image segmentation Non-convex optimization Mumford-Shah(MS)model Alternating direction method of multipliers(ADMMs) proximal operator

Creation and validation of a novel low-cost dry lab for early resident training and assessment of robotic prostatectomy technical proficiency

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Current Urology 2024年第2期18卷 133-138页

作者： kevin Kunitsky Abhishek Venkataramana Katherine E.Fero Jorge Ballon Jacob Komberg Robert Reiter Wayne Brisbane Institute of Urologic Oncology Department of UrologyDavid Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA Charles E.Schmidt College of Medicine Florida Atlantic UniversityBoca RatonFLUSA

purpose:To evaluate the preliminary validity and acceptability of a low-cost low-fidelity robotic surgery dry lab for training and assessing residents’technical proficiency with key robotic radical prostatectomy *** and methods:Three standardized inanimate tasks were created to simulate the radical prostatectomy steps of posterior dissection,neurovascular bundle release,and urethrovesical *** trainees and faculty at a single institution completed and evaluated each dry lab *** validity was evaluated by comparing task completion times and Global Evaluative Assessment of Robotic Skills scores across four participant cohorts:medical students(n=5),junior residents(n=5),senior residents(n=5),and attending surgeons(n=7).Content validity,face validity,and acceptabilitywere evaluated through a posttask survey using a 5-point Likert ***:There was a significant difference in the individual and composite task completion times and Global Evaluative Assessment of Robotic Skills scores across all participant cohorts(all pptability for use in residency ***,model realism,compared with human tissue,was poorly *** dry lab production cost was less than US$***:This low-cost procedure-specific dry lab demonstrated evidence of content validity,construct validity,and acceptability for simulating key robotic prostatectomy technical steps and can be used to augment robot-assisted laparoscopic prostatectomy surgical training.

关键词： Robotic surgery education Radical prostatectomy Simulation Dry laboratory Validation

Knowledge, attitudes, and practices regarding Covid-19 and their relationship with Covid-19 booster vaccination status among women with infertility

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Asian pacific Journal of Reproduction 2024年第2期13卷 68-75页

作者： Gita pratama Mila Maidarti Kanadi Sumapradja Achmad Kemal Harzif Natasha Talya kevin Ezekia Irfan Arieqal Hatta Ampri Reproductive Immunoendocrinology Division Department of Obstetrics and GynecologyFaculty of Medicine Universitas Indonesia-dr.Cipto Mangunkusumo General HospitalJakartaIndonesia Yasmin IVF Clinic dr.Cipto Mangunkusumo General Hospital JakartaIndonesia Human Reproduction Infertilityand Family Planning ClusterIndonesia Reproductive Medicine Research and Training CenterFaculty of MedicineUniversitas IndonesiaJakarta 10430Indonesia Department of Obstetrics and Gynecology Faculty of Medicine Universitas Indonesia-dr.Cipto Mangunkusumo General HospitalJakartaIndonesia

Objective:To elucidate the relationship among knowledge,attitudes,and practices regarding Covid-19 and their relationship with booster vaccination status among women with ***:This questionnaire-based cross-sectional study was performed online and offline among women with infertility who visited an infertility clinic in Jakarta,*** assessed the patient’s knowledge,attitudes,and practices regarding Covid-19 and their relationship with booster vaccination status and sociodemographic ***:A total of 178 subjects participated in this study,and most participants(92.6%)had received booster Covid-19 *** the questionnaire,74.2%had good knowledge,and 99.4%had good attitudes regarding Covid-19;however,only 57.9%of patients had good practices.A weak positive correlation existed between knowledge and attitudes(r=0.11,p=0.13)and a moderate negative correlation between attitudes and practices(r=-0.44,p=0.56).participants’knowledge about vaccines and infertility was correlated with booster vaccination status(p=0.04).Academic background(p=0.01)and attitudes(p=0.01)were also correlated with booster vaccination *** significant determinants of hesitance of receiving Covid-19 booster vaccines were high school education or below(OR=0.08,95%CI 0.02-0.36)and poor practices(OR=0.21,95%CI 0.05-0.95).Conclusions:The majority of the participants had received the Covid-19 booster vaccine and had good knowledge and attitudes but poor practices regarding *** participants had poor knowledge about the relationship between infertility and the Covid-19 *** general population should be more informed and reminded about practices to prevent Covid-19 and the relationship between vaccination and fertility to increase the number of people who receive Covid-19 booster vaccines.

关键词： Covid-19 Booster vaccine Infertility Knowledge Attitude practice Human reproduction pandemic

Interfacial engineering through lead binding using crown ethers in perovskite solar cells

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Journal of Energy Chemistry 2024年第5期92卷 263-270页

作者： Sun-Ju Kim YeonJu Kim Ramesh Kumar Chitumalla Gayoung Ham Thanh-Danh Nguyen Joonkyung Jang Hyojung Cha Jovana Milić Jun-Ho Yum kevin Sivula Ji-Youn Seo Department of Nano Fusion Technology Pusan National UniversityBusan 46241Republic of Korea Laboratory for Molecular Engineering of Optoelectronic Nanomaterials Institute of Chemical Sciences and EngineeringÉcole Polytechnique Fédérale de Lausanne(EPFL)1015 LausanneSwitzerland Department of Energy Convergence and Climate Change Kyungpook National UniversityDaegu 41566Republic of Korea Department of Hydrogen and Renewable Energy Kyungpook National UniversityDaegu 41566Republic of Korea Adolphe Merkle Institute University of FribourgCH-1700 FribourgSwitzerland

In the domain of perovskite solar cells(pSCs),the imperative to reconcile impressive photovoltaic performance with lead-related issue and environmental stability has driven innovative *** study pioneers an approach that not only rectifies lead leakage but also places paramount importance on the attainment of rigorous interfacial *** ethers,notably benzo-18-crown-6-ether(B18C6),were strategically integrated at the perovskite-hole transport material *** ethers exhibit a dual role:efficiently sequestering and immobilizing pb^(2+)ions through host-guest complexation and simultaneously establishing a robust interfacial passivation *** crown ether candidates,guided by density functional theory(DFT)calculations,demonstrated proficiency in binding pb2+ions and optimizing interfacial *** devices incorporating these materials achieved exceptional power conversion efficiency(pCE),notably 21.7%for B18C6,underscoring their efficacy in lead binding and interfacial *** techniques,including time-of-flight secondary ion mass spectrometry(ToF-SIMS),ultraviolet photoelectron spectroscopy(UpS),time-resolved photoluminescence(TRpL),and transient absorption spectroscopy(TAS),unequivocally affirmed pb^(2+)ion capture and suppression of non-radiative ***,these pSCs maintained efficiency even after enduring 300 h of exposure to 85%relative *** research underscores the transformative potential of crown ethers,simultaneously addressing lead binding and stringent interfacial passivation for sustainable pSCs poised to commercialize and advance renewable energy applications.

关键词： perovskite solar cells Interfacial passivation Crown ether materials Stability

Dynamics of self-hybridized exciton–polaritons in 2D halide perovskites

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Light(Science & Applications) 2024年第1期13卷 13-22页

作者： Surendra B.Anantharaman Jason Lynch Christopher E.Stevens Christopher Munley Chentao Li Jin Hou Hao Zhang Andrew Torma Thomas Darlington Francis Coen kevin Li Arka Majumdar pJames Schuck Aditya Mohite Hayk Harutyunyan Joshua R.Hendrickson Deep Jariwala Department of Electrical and Systems Engineering University of PennsylvaniaPhiladelphiaPA19104USA KBR Inc. BeavercreekOH45431USA Air Force Research Laboratory Sensors DirectorateWright-Patterson Air Force BaseOH45433USA Department of physics University of WashingtonSeattleWA98195USA Department of physics Emory UniversityAtlantaGA30322USA Department of Chemical and Biomolecular Engineering Rice UniversityHoustonTX77005USA Department of Materials Science and Nanoengineering Rice UniversityHoustonTX77005USA Applied physics program Smalley‐Curl InstituteRice UniversityHoustonTX77005USA Department of Mechanical Engineering Columbia UniversityNew YorkNY10027USA Department of Electrical and Computer Engineering University of WashingtonSeattleWA98195USA

Excitons,bound electron–hole pairs,in two-dimensional hybrid organic inorganic perovskites(2D HOIps)are capable of forming hybrid light-matter states known as exciton-polaritons(E–ps)when the excitonic medium is confined in an optical *** the case of 2D HOIps,they can self-hybridize into E–ps at specific thicknesses of the HOIp crystals that form a resonant optical cavity with the ***,the fundamental properties of these self-hybridized E–ps in 2D HOIps,including their role in ultrafast energy and/or charge transfer at interfaces,remain ***,we demonstrate that>0.5µm thick 2D HOIp crystals on Au substrates are capable of supporting multiple-orders of self-hybridized E–p *** E–ps have high Q factors(>100)and modulate the optical dispersion for the crystal to enhance sub-gap absorption and *** varying excitation energy and ultrafast measurements,we also confirm energy transfer from higher energy E–ps to lower energy E–***,we also demonstrate that E–ps are capable of charge transport and transfer at *** findings provide new insights into charge and energy transfer in E–ps opening new opportunities towards their manipulation for polaritonic devices.

关键词： charge polar excitation