Magnetisation of magnetite nanoparticles medium with dipol-dipol interaction

International Nuclear Information System (INIS)

Ali-zade, R. A.

2005-01-01

Full text: Magnetisation expression for magnetite nanoparticles medium with dipo-dipol interaction has been obtained. We suggested, that energy magnetic dipol-dipol interaction of magnetite nanopaticles is determined by: E d-d = - m 2 /4πμ 0 r 3 (cth x -1/x) 2 where x=mH/kT. This expression has been substituted in statistical sum of magnetite nanoparticles medium. Obtained statistical sum consists the production of two statistical sums. The first statistical sum described non-interacting magnetite nanoparticle medium and from this is obtained Langevan equation. Second statistical sum is: Z 2 -∫exp(Σm 2 /4π 0 r 3 (cth x -1/x) 2 ) dΩ 2 . The second statistical sum has been expanded in Taylor's set and taken into consideration first two terms. Integration has been carried out over all volume. In this case take into account that, number twice interactions of magnetite nanoparticles in unit volume is equal to N(N-1)/2 at N>>1 to N 2 /2. We obtain expressions for magnetisation and initial magnetic susceptibility of interacting magnetite nanoparticles medium take into account that Φ=-kT ln Z, M=-dΦ/dH, χ=dM/dH: M=M Sφm (cth x -1/x)+ 1/3 M S 2 φ m 2 (1μ 0 H) ln(VM S /kT).(cth x -1/x)(-xcsch 2 x+1/x) χ 0 =1/3 (m/kT)+ 1/27 M S 2 φ m 2 (1μ 0 )ln(VM S /kT).(m/kT) 2 . Second term in the magnetisation is sufficient at weak and middle magnetic fields. At large magnetic fields, it leads to zero. The second term of magnetisation has maximum at x=1.566. The values of experimental and calculated magnetic field corresponding to magnetisation maximum for magnetite nanoparticles medium (mean diameter of nanoparticle is 9.4 nm) are 1.19 10 4 A/m and 1.25 10 4 A/m respectively. Magnetic dipol-dipol interaction influence to magnetisation of magnetite nanoparticles. Magnetite nanoparticles lined along external magnetic fields line and formatted chains. Magnetisation of medium occurs by the 'parallel' mechanism method magnetisation of chains

Amide proton transfer imaging for differentiation of benign and atypical meningiomas

Energy Technology Data Exchange (ETDEWEB)

Joo, Bio [The Armed Forces Capital Hospital, Department of Radiology, Seongnam, Gyeonggi-do (Korea, Republic of); Han, Kyunghwa; Choi, Yoon Seong; Lee, Seung-Koo [Yonsei University College of Medicine, Department of Radiology and Research Institute of Radiological Science, College of Medicine, Seoul (Korea, Republic of); Ahn, Sung Soo [Yonsei University College of Medicine, Department of Radiology and Research Institute of Radiological Science, College of Medicine, Seoul (Korea, Republic of); Yonsei University, Department of Radiology, College of Medicine, Seoul (Korea, Republic of); Chang, Jong Hee; Kang, Seok-Gu [Yonsei University College of Medicine, Department of Neurosurgery, Seoul (Korea, Republic of); Kim, Se Hoon [Yonsei University College of Medicine, Department of Pathology, Seoul (Korea, Republic of); Zhou, Jinyuan [Johns Hopkins University School of Medicine, Division of MRI Research, Department of Radiology, Baltimore, MD (United States)

2018-01-15

To investigate the difference in amide proton transfer (APT)-weighted signals between benign and atypical meningiomas and determine the value of APT imaging for differentiating the two. Fifty-seven patients with pathologically diagnosed meningiomas (benign, 44; atypical, 13), who underwent preoperative MRI with APT imaging between December 2014 and August 2016 were included. We compared normalised magnetisation transfer ratio asymmetry (nMTR{sub asym}) values between benign and atypical meningiomas on APT-weighted images. Conventional MRI features were qualitatively assessed. Both imaging features were evaluated by multivariable logistic regression analysis. The discriminative value of MRI with and without nMTR{sub asym} was evaluated. The nMTR{sub asym} of atypical meningiomas was significantly greater than that of benign meningiomas (2.46% vs. 1.67%; P < 0.001). In conventional MR images, benign and atypical meningiomas exhibited significant differences in maximum tumour diameter, non-skull base location, and heterogeneous enhancement. On multivariable logistic regression analysis, high nMTR{sub asym} was an independent predictor of atypical meningiomas (adjusted OR, 11.227; P = 0.014). The diagnostic performance of MRI improved with nMTR{sub asym} for predicting atypical meningiomas. Atypical meningiomas exhibited significantly higher APT-weighted signal intensities than benign meningiomas. The discriminative value of conventional MRI improved significantly when combined with APT imaging for diagnosis of atypical meningioma. (orig.)

Magnetisation processes and magnetic viscosity of mechanically alloyed SmCo5

International Nuclear Information System (INIS)

Ding, J.; Smith, P.A.I.; McCormick, P.G.; Street, R.

1996-01-01

Mechanically alloyed SmCo 5 materials with coercivities in the range of 50-75 kOe were studied in this work. Irreversible magnetisation processes were investigated by measuring remanences after initial magnetisation and after demagnetisation. A large deviation of the demagnetisation remanence from the Wohlfarth relationship indicated that interactions between grains play an important role in the irreversible magnetisation process. Viscosity tests showed nearly linear relationship between the magnetic field and the viscosity parameter for the initial magnetisation, while the viscosity was not strongly dependent on the field for the demagnetisation. High values of the viscosity parameter, Λ, between 120 to 220 Oe were measured at fields near coercivity. (orig.)

Spin and orbital magnetisation densities determined by Compton scattering of photons

International Nuclear Information System (INIS)

Collins, S.P.; Laundy, D.; Cooper, M.J.; Lovesey, S.W.; Uppsala Univ.

1990-03-01

Compton scattering of a circularly polarized photon beam is shown to provide direct information on orbital and spin magnetisation densities. Experiments are reported which demonstrate the feasibility of the method by correctly predicting the ratio of spin and orbital magnetisation components in iron and cobalt. A partially polarised beam of 45 keV photons from the Daresbury Synchrotron Radiation Source produces charge-magnetic interference scattering which is measured by a field-difference method. Theory shows that the interference cross section contains the Compton profile of polarised electrons modulated by a structure factor which is a weighted sum of spin and orbital magnetisations. In particular, the scattering geometry for which the structure factor vanishes yields a unique value for the ratio of the magnetisation densities. Compton scattering, being an incoherent process, provides data on total unit cell magnetisations which can be directly compared with bulk data. In this respect, Compton scattering complements magnetic neutron and photon Bragg diffraction. (author)

X-ray imaging of spin currents and magnetisation dynamics at the nanoscale

International Nuclear Information System (INIS)

Bonetti, Stefano

2017-01-01

Understanding how spins move in time and space is the aim of both fundamental and applied research in modern magnetism. Over the past three decades, research in this field has led to technological advances that have had a major impact on our society, while improving the understanding of the fundamentals of spin physics. However, important questions still remain unanswered, because it is experimentally challenging to directly observe spins and their motion with a combined high spatial and temporal resolution. In this article, we present an overview of the recent advances in x-ray microscopy that allow researchers to directly watch spins move in time and space at the microscopically relevant scales. We discuss scanning x-ray transmission microscopy (STXM) at resonant soft x-ray edges, which is available at most modern synchrotron light sources. This technique measures magnetic contrast through the x-ray magnetic circular dichroism (XMCD) effect at the resonant absorption edges, while focusing the x-ray radiation at the nanometre scale, and using the intrinsic pulsed structure of synchrotron-generated x-rays to create time-resolved images of magnetism at the nanoscale. In particular, we discuss how the presence of spin currents can be detected by imaging spin accumulation, and how the magnetisation dynamics in thin ferromagnetic films can be directly imaged. We discuss how a direct look at the phenomena allows for a deeper understanding of the the physics at play, that is not accessible to other, more indirect techniques. Finally, we present an overview of the exciting opportunities that lie ahead to further understand the fundamentals of novel spin physics, opportunities offered by the appearance of diffraction limited storage rings and free electron lasers. (topical review)

SQUID measurements of remanent magnetisation in refillable 3He spin-filter cells (SFC)

Science.gov (United States)

Hutanu, V.; Rupp, A.; Sander-Thömmes, T.

2007-07-01

A strong influence of external magnetic fields on the relaxation time constant T1 of glass cells serving as reservoirs for polarised 3He, observed for various alkali metal-coated cells made of different glass types, was initially associated with the presence of a large number of ferromagnetic clusters on the glass surface. Later experiments showed the presence of the so-called “ T1 hysteresis” phenomenon with a similar distinctiveness also in uncoated cells made of pure synthetic quartz glass. It suggests that the origin of such a relaxation is a macroscopic magnetisation in the bulk of the cell. We present the results of a multi-SQUID system investigation on magnetised and non-magnetised quartz glass cells, Cs coated as well as bare wall, to be used as neutron spin filters at HMI Berlin. The presence of a macroscopic remanent magnetic moment in the cells after their exposition to external magnetic fields has been experimentally shown. More than 80% of the remanent magnetic moment of the magnetised cells was found to be concentrated in the region of the glass valves. SQUID measurements reveal the existence of some remanent magnetisation in all valve parts and also in the vacuum grease, but most magnetic are the plastic parts and the O-ring. Different valve and sealing types have been compared in order to find the less magnetisable one.

Single crystal magnetisation of UFe10Mo2

International Nuclear Information System (INIS)

Estrela, P.; Godinho, M.; Spirlet, J.C.

1997-01-01

Magnetisation measurements have been performed for different directions on aligned UFe 10 Mo 2 single crystals. The results confirm a basal plane anisotropy and suggest an important magnetic contribution from the uranium sublattice. (orig.)

Induced voltage due to time-dependent magnetisation textures

International Nuclear Information System (INIS)

Kudtarkar, Santosh Kumar; Dhadwal, Renu

2010-01-01

We determine the induced voltage generated by spatial and temporal magnetisation textures (inhomogeneities) in metallic ferromagnets due to the spin diffusion of non-equilibrium electrons. Using time dependent semi-classical theory as formulated in Zhang and Li and the drift-diffusion model of transport it is shown that the voltage generated depends critically on the difference in the diffusion constants of up and down spins. Including spin relaxation results in a crucial contribution to the induced voltage. We also show that the presence of magnetisation textures results in the modification of the conductivity of the system. As an illustration, we calculate the voltage generated due to a time dependent field driven helimagnet by solving the Landau-Lifshitz equation with Gilbert damping and explicitly calculate the dependence on the relaxation and damping parameters.

Holographic magnetisation density waves

Energy Technology Data Exchange (ETDEWEB)

Donos, Aristomenis [Centre for Particle Theory and Department of Mathematical Sciences, Durham University,Stockton Road, Durham, DH1 3LE (United Kingdom); Pantelidou, Christiana [Departament de Fisica Quantica i Astrofisica & Institut de Ciencies del Cosmos (ICC),Universitat de Barcelona,Marti i Franques 1, 08028 Barcelona (Spain)

2016-10-10

We numerically construct asymptotically AdS black brane solutions of D=4 Einstein theory coupled to a scalar and two U(1) gauge fields. The solutions are holographically dual to d=3 CFTs in a constant external magnetic field along one of the U(1)’s. Below a critical temperature the system’s magnetisation density becomes inhomogeneous, leading to spontaneous formation of current density waves. We find that the transition can be of second order and that the solutions which minimise the free energy locally in the parameter space of solutions have averaged stressed tensor of a perfect fluid.

Soft X-ray magnetic scattering study of rotational magnetisation processes in cobalt/copper multilayers

International Nuclear Information System (INIS)

Hase, T.P.A.; Fulthorpe, B.D.; Wilkins, S.B.; Tanner, B.K.; Marrows, C.H.; Hickey, B.J.

2001-01-01

We report the observation of magnetic viscosity in the intensity of resonant magnetic soft X-ray scattering during rotational magnetisation processes in antiferromagnetically coupled Co/Cu multilayers. The hysteretic time-dependent component of the signal can be fitted to a single-exponential function that varies as a function of magnetising field

Hybrid MR-PET of brain tumours using amino acid PET and chemical exchange saturation transfer MRI.

Science.gov (United States)

da Silva, N A; Lohmann, P; Fairney, J; Magill, A W; Oros Peusquens, A-M; Choi, C-H; Stirnberg, R; Stoffels, G; Galldiks, N; Golay, X; Langen, K-J; Jon Shah, N

2018-06-01

PET using radiolabelled amino acids has become a promising tool in the diagnostics of gliomas and brain metastasis. Current research is focused on the evaluation of amide proton transfer (APT) chemical exchange saturation transfer (CEST) MR imaging for brain tumour imaging. In this hybrid MR-PET study, brain tumours were compared using 3D data derived from APT-CEST MRI and amino acid PET using O-(2- 18 F-fluoroethyl)-L-tyrosine ( 18 F-FET). Eight patients with gliomas were investigated simultaneously with 18 F-FET PET and APT-CEST MRI using a 3-T MR-BrainPET scanner. CEST imaging was based on a steady-state approach using a B 1 average power of 1μT. B 0 field inhomogeneities were corrected a Prametric images of magnetisation transfer ratio asymmetry (MTR asym ) and differences to the extrapolated semi-solid magnetisation transfer reference method, APT# and nuclear Overhauser effect (NOE#), were calculated. Statistical analysis of the tumour-to-brain ratio of the CEST data was performed against PET data using the non-parametric Wilcoxon test. A tumour-to-brain ratio derived from APT# and 18 F-FET presented no significant differences, and no correlation was found between APT# and 18 F-FET PET data. The distance between local hot spot APT# and 18 F-FET were different (average 20 ± 13 mm, range 4-45 mm). For the first time, CEST images were compared with 18 F-FET in a simultaneous MR-PET measurement. Imaging findings derived from 18 F-FET PET and APT CEST MRI seem to provide different biological information. The validation of these imaging findings by histological confirmation is necessary, ideally using stereotactic biopsy.

High-temperature magnetisation measurements on the pearlite transformation kinetics in nearly eutectoid steel

International Nuclear Information System (INIS)

Dijk, N.H. van; Offerman, S.E.; Klaasse, J.C.P.; Sietsma, J.; Zwaag, S. van der

2004-01-01

The isothermal transformation kinetics of the austenite to pearlite transformation in (nearly) eutectoid steel was studied by in situ magnetisation measurements at high temperatures. In eutectoid steel the high temperature austenite (γ-Fe) phase decomposes into pearlite, which consists of a lamellar structure of ferrite (α-Fe) and cementite (Fe 3 C). Below the Curie temperature of ferrite T C =1043 K the ferrite phase fraction can be probed by the magnetisation measurements. For our nearly eutectoid steel not only pearlite but also a small fraction of pro-eutectoid ferrite is formed. The transformation kinetics of the pearlite and the pro-eutectoid ferrite is studied by magnetisation measurements as a function of the isothermal transformation temperature and compared with the results from additional dilatometry measurements. The transformation kinetics was found to vary over four orders of magnitude over the range of transformation temperatures and was compared with model predictions

Optic nerve magnetisation transfer ratio after acute optic neuritis predicts axonal and visual outcomes.

Directory of Open Access Journals (Sweden)

Yejun Wang

Full Text Available Magnetisation transfer ratio (MTR can reveal the degree of proton exchange between free water and macromolecules and was suggested to be pathological informative. We aimed to investigate changes in optic nerve MTR over 12 months following acute optic neuritis (ON and to determine whether MTR measurements can predict clinical and paraclinical outcomes at 6 and 12 months. Thirty-seven patients with acute ON were studied within 2 weeks of presentation and at 1, 3, 6 and 12 months. Assessments included optic nerve MTR, retinal nerve fibre layer (RNFL thickness, multifocal visual evoked potential (mfVEP amplitude and latency and high (100% and low (2.5% contrast letter acuity. Eleven healthy controls were scanned twice four weeks apart for comparison with patients. Patient unaffected optic nerve MTR did not significantly differ from controls at any time-point. Compared to the unaffected nerve, affected optic nerve MTR was significantly reduced at 3 months (mean percentage interocular difference = -9.24%, p = 0.01, 6 months (mean = -12.48%, p<0.0001 and 12 months (mean = -7.61%, p = 0.003. Greater reduction in MTR at 3 months in patients was associated with subsequent loss of high contrast letter acuity at 6 (ρ = 0.60, p = 0.0003 and 12 (ρ = 0.44, p = 0.009 months, low contrast letter acuity at 6 (ρ = 0.35, p = 0.047 months, and RNFL thinning at 12 (ρ = 0.35, p = 0.044 months. Stratification of individual patient MTR time courses based on flux over 12 months (stable, putative remyelination and putative degeneration predicted RNFL thinning at 12 months (F(2,32 = 3.59, p = 0.02. In conclusion, these findings indicate that MTR flux after acute ON is predictive of axonal degeneration and visual disability outcomes.

Gravity Defied From Potato Asteroids to Magnetised Neutron Stars

Indian Academy of Sciences (India)

Gravity Defied. From Potato Asteroids to Magnetised Neutron Stars. 2. ... objects that just missed being stars in this particular install- ment. 1. .... However, the total energy that can be made .... trial metals in which the electrons form a degenerate Fermi gas. ... In deuterium fusion, a deuterium nucleus and a proton combine to.

Imaging outcomes for trials of remyelination in multiple sclerosis.

Science.gov (United States)

Mallik, Shahrukh; Samson, Rebecca S; Wheeler-Kingshott, Claudia A M; Miller, David H

2014-12-01

Trials of potential neuroreparative agents are becoming more important in the spectrum of multiple sclerosis research. Appropriate imaging outcomes are required that are feasible from a time and practicality point of view, as well as being sensitive and specific to myelin, while also being reproducible and clinically meaningful. Conventional MRI sequences have limited specificity for myelination. We evaluate the imaging modalities which are potentially more specific to myelin content in vivo, such as magnetisation transfer ratio (MTR), restricted proton fraction f (from quantitative magnetisation transfer measurements), myelin water fraction and diffusion tensor imaging (DTI) metrics, in addition to positron emission tomography (PET) imaging. Although most imaging applications to date have focused on the brain, we also consider measures with the potential to detect remyelination in the spinal cord and in the optic nerve. At present, MTR and DTI measures probably offer the most realistic and feasible outcome measures for such trials, especially in the brain. However, no one measure currently demonstrates sufficiently high sensitivity or specificity to myelin, or correlation with clinical features, and it should be useful to employ more than one outcome to maximise understanding and interpretation of findings with these sequences. PET may be less feasible for current and near-future trials, but is a promising technique because of its specificity. In the optic nerve, visual evoked potentials can indicate demyelination and should be correlated with an imaging outcome (such as optic nerve MTR), as well as clinical measures. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Simulation and Analysis of Magnetisation Characteristics of Interior Permanent Magnet Motors

Directory of Open Access Journals (Sweden)

J. A. Walker

2005-01-01

Full Text Available Modern permanent magnet (PM synchronous brushless machines often have magnetic circuits in which the patterns of saturation are complex and highly variable with the position of the rotor. The classical phasor diagram theory of operation relies on the assumption of sinusoidal variation of flux-linkage with rotor position, and neglects the non-linear effects that arise in different operating states. The finite element method is a useful tool for detailed magnetic analysis, but it is important to verify simulation results by direct measurement of the magnetic characteristics of the motor, in terms of “magnetisation curves” of current and flux-linkage. This paper presents results from finite element simulations to determine the magnetisation in a split-phase interior permanent magnet (IPM motor. Investigation has been made to determine the effects of the rotor geometry on the synchronous reactances and airgap flux distribution. Comparisons are made with a second IPM motor with a different rotor configuration. 

Magnetisation switching in a ferromagnetic Heisenberg nanoparticle with uniaxial anisotropy: a Monte Carlo investigation

International Nuclear Information System (INIS)

Ledue, D.; Berche, P.E.; Patte, R.

2004-01-01

We investigate the thermal-activated magnetisation reversal in a single ferromagnetic nanoparticle with uniaxial anisotropy using Monte Carlo simulations. The aim of this work is to reproduce the reversal magnetisation by uniform rotation at very low temperature in the high-energy barrier hypothesis, that is to realize the Neel-Brown model. For this purpose we have considered a simple cubic nanoparticle where each site is occupied by a classical Heisenberg spin. The Hamiltonian is the sum of an exchange interaction term, a single-ion anisotropy term and a Zeeman interaction term. Our numerical data of the thermal variation of the switching field are compared to an approximated expression and previous experimental results on Co nanoparticles

The Magnetisation of MnB and its Variation with Temperature

Energy Technology Data Exchange (ETDEWEB)

Lundquist, N; Myers, H P

1960-12-15

It has been shown that MnB is the only ferromagnetic phase occurring in the Mn-B system. The magnetisation per unit mass at 0 K and in infinite field strength has been found to be 163 corresponding to a Bohr magneton value 1.92 per Mn atom. The Curie temperature in zero field is 300 C. The significance of this magnetic data is discussed.

Remote transfer of PET images by internet

International Nuclear Information System (INIS)

Zuo Chuantao; Lin Xiangtong; Guan Yihui; Zhao Jun

2003-01-01

The methodology of PET image remote transfer by Internet has been explored. The original images were got with ECAT EXACT HR + PET, and then converted to Dicom format by Mview software. The Dicom images were transferred via Internet. Thus the PET images were transferred via Internet successfully. The ideal images were obtained away from 8 km. The transfer time of brain and whole body image was (37±3)s and (245±10)s respectively, while the transfer rate was (34.7±2.8) kbyte/s and (34.4±1.5)kbyte/s, respectively. The results showed that the remote transfer via Internet was feasible and practical

The relationship between magnetisation and hysteresis of critical current in sintered YBCO. [Y-Ba-Cu-O

Energy Technology Data Exchange (ETDEWEB)

Jones, A R; Blunt, F J; Campbell, A M [Research Centre in Superconductivity, Univ. of Cambridge (United Kingdom); Doyle, R A [Dept. of Physics, Univ. of Witwatersrand (South Africa)

1992-06-10

Measurements are reported of transport critical current and magnetisation on the same samples of YBCO for three different orientations with respect to applied magnetic field. The predictions made by the model of Evetts and Glowacki for the hysteresis observed in J{sub c} were investigated and found to be in qualitative agreement with the results. However, attempts to relate the hysteresis to the magnetisation by assuming that J{sub c} is a unique function of the internal field H = H{sub 0}-nM were unsuccessful. The value of n is found to be much larger than any demagnetising factor and varies widely with both field and geometry. (orig.).

Role of magnetic resonance imaging in the management of perianal Crohn's disease.

Science.gov (United States)

Gallego, Jose C; Echarri, Ana

2018-02-01

Perianal fistulas are a major problem in many patients with Crohn's disease. These are usually complex fistulas that adversely affect patients' quality of life, and their clinical management is difficult. Medical treatment sometimes achieves cessation of discharge and closure of the external opening; however, it is difficult to assess the status of the rest of the fistula tract. Magnetic resonance imaging is the method of choice with which to evaluate the condition of perianal fistulas and allows for assessment of the status of inaccessible areas. Magnetic resonance imaging also allows the clinician to evaluate other perianal manifestations of Crohn's disease that differ from the fistulas. This imaging technique is therefore a fundamental means of patient monitoring. When used in conjunction with assessment of the patient's morphological findings, it provides information that allows for both quantification of disease severity and evaluation of the response to treatment. New types of magnetic resonance sequences are emerging, such as diffusion, perfusion, and magnetisation transfer. These sequences may serve as biomarkers because they provide information reflecting the changes taking place at the molecular level. This will help to shape a new scenario in the early assessment of the response to treatments such as anti-tumour necrosis factor drugs. • MRI is the method of choice with which to evaluate perianal fistulas. • In perianal Crohn's disease, MRI is a fundamental means of patient monitoring. • The usefulness of the Van Assche score for patient monitoring remains unclear. • New MRI sequences' diffusion, perfusion, and magnetisation transfer may serve as biomarkers.

Resonance Energy Transfer Molecular Imaging Application in Biomedicine

Directory of Open Access Journals (Sweden)

NIE Da-hong1,2;TANG Gang-hua1,3

2016-11-01

Full Text Available Resonance energy transfer molecular imaging (RETI can markedly improve signal intensity and tissue penetrating capacity of optical imaging, and have huge potential application in the deep-tissue optical imaging in vivo. Resonance energy transfer (RET is an energy transition from the donor to an acceptor that is in close proximity, including non-radiative resonance energy transfer and radiative resonance energy transfer. RETI is an optical imaging technology that is based on RET. RETI mainly contains fluorescence resonance energy transfer imaging (FRETI, bioluminescence resonance energy transfer imaging (BRETI, chemiluminescence resonance energy transfer imaging (CRETI, and radiative resonance energy transfer imaging (RRETI. RETI is the hot field of molecular imaging research and has been widely used in the fields of biology and medicine. This review mainly focuses on RETI principle and application in biomedicine.

Transfer function analysis of radiographic imaging systems

International Nuclear Information System (INIS)

Metz, C.E.; Doi, K.

1979-01-01

The theoretical and experimental aspects of the techniques of transfer function analysis used in radiographic imaging systems are reviewed. The mathematical principles of transfer function analysis are developed for linear, shift-invariant imaging systems, for the relation between object and image and for the image due to a sinusoidal plane wave object. The other basic mathematical principle discussed is 'Fourier analysis' and its application to an input function. Other aspects of transfer function analysis included are alternative expressions for the 'optical transfer function' of imaging systems and expressions are derived for both serial and parallel transfer image sub-systems. The applications of transfer function analysis to radiographic imaging systems are discussed in relation to the linearisation of the radiographic imaging system, the object, the geometrical unsharpness, the screen-film system unsharpness, other unsharpness effects and finally noise analysis. It is concluded that extensive theoretical, computer simulation and experimental studies have demonstrated that the techniques of transfer function analysis provide an accurate and reliable means for predicting and understanding the effects of various radiographic imaging system components in most practical diagnostic medical imaging situations. (U.K.)

High field magnetisation studies in some rare earth based amorphous ribbons

Science.gov (United States)

Krishnan, R.; Lassri, H.; Driouch, L.

1995-02-01

We have carried out magnetisation studies at fields up to 20 T of melt spun amorphous Fe 72- xY xHo 8B 20 alloys. The approach to saturation for H ≤ 11 T has been analysed on the basis of Chudnovsky's model, and the exchange constant, random anisotropy etc. have been calculated. We have also extracted the local anisotropy from the coercivity.

Baby MIND: A Magnetised Spectrometer for the WAGASCI Experiment

Energy Technology Data Exchange (ETDEWEB)

Antonova, M.; et al.

2017-04-26

The WAGASCI experiment being built at the J-PARC neutrino beam line will measure the difference in cross sections from neutrinos interacting with a water and scintillator targets, in order to constrain neutrino cross sections, essential for the T2K neutrino oscillation measurements. A prototype Magnetised Iron Neutrino Detector (MIND), called Baby MIND, is being constructed at CERN to act as a magnetic spectrometer behind the main WAGASCI target to be able to measure the charge and momentum of the outgoing muon from neutrino charged current interactions.

Transfer learning improves supervised image segmentation across imaging protocols.

Science.gov (United States)

van Opbroek, Annegreet; Ikram, M Arfan; Vernooij, Meike W; de Bruijne, Marleen

2015-05-01

The variation between images obtained with different scanners or different imaging protocols presents a major challenge in automatic segmentation of biomedical images. This variation especially hampers the application of otherwise successful supervised-learning techniques which, in order to perform well, often require a large amount of labeled training data that is exactly representative of the target data. We therefore propose to use transfer learning for image segmentation. Transfer-learning techniques can cope with differences in distributions between training and target data, and therefore may improve performance over supervised learning for segmentation across scanners and scan protocols. We present four transfer classifiers that can train a classification scheme with only a small amount of representative training data, in addition to a larger amount of other training data with slightly different characteristics. The performance of the four transfer classifiers was compared to that of standard supervised classification on two magnetic resonance imaging brain-segmentation tasks with multi-site data: white matter, gray matter, and cerebrospinal fluid segmentation; and white-matter-/MS-lesion segmentation. The experiments showed that when there is only a small amount of representative training data available, transfer learning can greatly outperform common supervised-learning approaches, minimizing classification errors by up to 60%.

Transfer learning improves supervised image segmentation across imaging protocols

DEFF Research Database (Denmark)

van Opbroek, Annegreet; Ikram, M. Arfan; Vernooij, Meike W.

2015-01-01

with slightly different characteristics. The performance of the four transfer classifiers was compared to that of standard supervised classification on two MRI brain-segmentation tasks with multi-site data: white matter, gray matter, and CSF segmentation; and white-matter- /MS-lesion segmentation......The variation between images obtained with different scanners or different imaging protocols presents a major challenge in automatic segmentation of biomedical images. This variation especially hampers the application of otherwise successful supervised-learning techniques which, in order to perform...... well, often require a large amount of labeled training data that is exactly representative of the target data. We therefore propose to use transfer learning for image segmentation. Transfer-learning techniques can cope with differences in distributions between training and target data, and therefore...

Nonlinear interactions in magnetised piezoelectric semiconductor plasmas

International Nuclear Information System (INIS)

Sharma, Giriraj; Ghosh, S.

2000-01-01

Based on hydrodynamics model of plasmas an analytical investigation of frequency modulational interaction between copropagating high frequency pump and acoustic mode and consequent amplification (steady-state and transient) of the modulated waves is carried out in a magnetised piezoelectric semiconductor medium. The phenomenon of modulation amplification is treated as four wave interaction process involving cubic nonlinearity of the medium. Gain constants, threshold-pump intensities and optimum-pulse duration for the onset of modulational instabilities are estimated. The analysis has been performed in non-dispersive regime of the acoustic mode, which is one of the preconditions for achieving an appreciable initial steady-state growth of the modulated signal wave. It is found that the transient gain diminishes very rapidly if one chooses the pump pulse duration beyond the maximum gain point. Moreover, the desired value of the gain can be obtained by adjusting intensity and pulse duration of the pump and doping concentration of the medium concerned. (author)

Geophysical evidence for widespread reversely magnetised pyroclastics in the western Taupo Volcanic Zone (New Zealand)

International Nuclear Information System (INIS)

Soengkono, S.; Hochstein, M.P.; Smith, I.E.M.; Itaya, T.

1992-01-01

Low-altitude aeromagnetic data show that negative residual anomalies are widespread over the western Taupo Volcanic Zone, New Zealand. Paleomagnetic study of eight rhyolitic ignimbrite units and two lava flows which are exposed in this area, together with new K-Ar dates of four of the ignimbrite units, indicate that the two lava units and seven of the ignimbrite units were erupted during the Matuyama geomagnetic epoch (>0.73 Ma B.P.) and suggest that rhyolitic volcanism in the western Taupo Volcanic Zone began as early as 1.6 Ma B.P. These results provide the basis for an interpretation of our aeromagnetic data which confirms the hypothesis that the magnetic anomalies observed in the western Taupo Volcanic Zone are caused by widespread, thick, reversely magnetised pyroclastic and lava flows. Magnetic modelling also allows thickness estimates of the younger, normally magnetised cover rocks which reach a maximum thickness of the order of 0.5 km in the Mangakino area. The magnetic structure of these volcanic rocks defines approximately the lateral extent of the Mangakino Volcanic Centre. (author). 41 refs., 2 figs., 3 tabs

Image quality transfer and applications in diffusion MRI

DEFF Research Database (Denmark)

Alexander, Daniel C.; Zikic, Darko; Ghosh, Aurobrata

2017-01-01

This paper introduces a new computational imaging technique called image quality transfer (IQT). IQT uses machine learning to transfer the rich information available from one-off experimental medical imaging devices to the abundant but lower-quality data from routine acquisitions. The procedure u...

Magnetic resonance imaging findings after rectus femoris transfer surgery

International Nuclear Information System (INIS)

Gold, Garry E.; Asakawa, Deanna S.; Blemker, Silvia S.; Delp, Scott L.

2004-01-01

We describe the magnetic resonance (MR) imaging appearance of the knee flexor and extensor tendons after bilateral rectus femoris transfer and hamstring lengthening surgery in five patients (10 limbs) with cerebral palsy. Three-dimensional models of the path of the transferred tendon were constructed in all cases. MR images of the transferred and lengthened tendons were examined and compared with images from ten non-surgical subjects. The models showed that the path of the transferred rectus femoris tendon had a marked angular deviation near the transfer site in all cases. MR imaging demonstrated irregular areas of low signal intensity near the transferred rectus femoris and around the hamstrings in all subjects. Eight of the ten post-surgical limbs showed evidence of fluid near or around the transferred or lengthened tendons. This was not observed in the non-surgical subjects. Thus, MR imaging of patients with cerebral palsy after rectus femoris transfer and hamstring-lengthening surgery shows evidence of signal intensity and contour changes, even several years after surgery. (orig.)

A rational approach to the modulation of the dynamics of the magnetisation in a dysprosium-nitronyl-nitroxide radical complex.

Science.gov (United States)

Poneti, Giordano; Bernot, Kevin; Bogani, Lapo; Caneschi, Andrea; Sessoli, Roberta; Wernsdorfer, Wolfgang; Gatteschi, Dante

2007-05-14

A control of the dynamics of the magnetisation is chemically achieved in a ring-like Dy-radical based molecule, allowing the estimation of the quantum tunneling frequency with a (4)He-cooled susceptometer.

Real-time transfer and display of radiography image

International Nuclear Information System (INIS)

Liu Ximing; Wu Zhifang; Miao Jicheng

2000-01-01

The information process network of cobalt-60 container inspection system is a local area network based on PC. The system requires reliable transfer of radiography image between collection station and process station and the real-time display of radiography image on process station. Due to the very high data acquisition rate, in order to realize the real-time transfer and display of radiography image, 100 M Ethernet technology and network process communication technology are adopted in the system. Windows Sockets is the most common process communication technology up to now. Several kinds of process communication way under Windows Sockets technology are compared and tested. Finally the author realized 1 Mbyte/s' inerrant image transfer and real-time display with blocked datagram transfer technology

Non-invasive measurement and imaging of tissue iron oxide nanoparticle concentrations in vivo using proton relaxometry

International Nuclear Information System (INIS)

St Pierre, T G; Clark, P R; Chua-anusorn, W; Fleming, A; Pardoe, H; Jeffrey, G P; Olynyk, J K; Pootrakul, P; Jones, S; Moroz, P

2005-01-01

Magnetic nanoparticles and microparticles can be found in biological tissues for a variety of reasons including pathological deposition of biogenic particles, administration of synthetic particles for scientific or clinical reasons, and the inclusion of biogenic magnetic particles for the sensing of the geomagnetic field. In applied magnetic fields, the magnetisation of tissue protons can be manipulated with radiofrequency radiation such that the macroscopic magnetisation of the protons precesses freely in the plane perpendicular to the applied static field. The presence of magnetic particles within tissue enhances the rate of dephasing of proton precession with higher concentrations of particles resulting in higher dephasing rates. Magnetic resonance imaging instruments can be used to measure and image the rate of decay of spin echo recoverable proton transverse magnetisation (R 2 ) within tissues enabling the measurement and imaging of magnetic particle concentrations with the aid of suitable calibration curves. Applications include the non-invasive measurement of liver iron concentrations in iron-overload disorders and measurement and imaging of magnetic particle concentrations used in magnetic hyperthermia therapy. Future applications may include the tracking of magnetically labelled drugs or biomolecules and the measurement of fibrotic liver damage

Two-magnon bound state causes ultrafast thermally induced magnetisation switching

Science.gov (United States)

Barker, J.; Atxitia, U.; Ostler, T. A.; Hovorka, O.; Chubykalo-Fesenko, O.; Chantrell, R. W.

2013-01-01

There has been much interest recently in the discovery of thermally induced magnetisation switching using femtosecond laser excitation, where a ferrimagnetic system can be switched deterministically without an applied magnetic field. Experimental results suggest that the reversal occurs due to intrinsic material properties, but so far the microscopic mechanism responsible for reversal has not been identified. Using computational and analytic methods we show that the switching is caused by the excitation of two-magnon bound states, the properties of which are dependent on material factors. This discovery allows us to accurately predict the onset of switching and the identification of this mechanism will allow new classes of materials to be identified or designed for memory devices in the THz regime. PMID:24253110

Transfer and conversion of images based on EIT in atom vapor.

Science.gov (United States)

Cao, Mingtao; Zhang, Liyun; Yu, Ya; Ye, Fengjuan; Wei, Dong; Guo, Wenge; Zhang, Shougang; Gao, Hong; Li, Fuli

2014-05-01

Transfer and conversion of images between different wavelengths or polarization has significant applications in optical communication and quantum information processing. We demonstrated the transfer of images based on electromagnetically induced transparency (EIT) in a rubidium vapor cell. In experiments, a 2D image generated by a spatial light modulator is used as a coupling field, and a plane wave served as a signal field. We found that the image carried by coupling field could be transferred to that carried by signal field, and the spatial patterns of transferred image are much better than that of the initial image. It also could be much smaller than that determined by the diffraction limit of the optical system. We also studied the subdiffraction propagation for the transferred image. Our results may have applications in quantum interference lithography and coherent Raman spectroscopy.

Magnetization transfer imaging identifies basal ganglia abnormalities in adult ADHD that are invisible to conventional T1 weighted voxel-based morphometry

Directory of Open Access Journals (Sweden)

Arjun Sethi

2017-01-01

Full Text Available In childhood, Attention Deficit Hyperactivity Disorder (ADHD is reliably associated with reduced volume of the striatum. In contrast, striatal abnormalities are infrequently detected in voxel-based morphometry (VBM neuroimaging studies of adults with ADHD. This discrepancy has been suggested to reflect normalisation of striatal morphology with age and prolonged treatment of symptoms. If so, this would indicate that while striatal abnormalities are linked to symptom expression in childhood, they cannot explain the persistence of these symptoms in adulthood. However, this may not be case. Instead, we hypothesized that the lack of evidence for striatal abnormalities in adult ADHD may reflect poor sensitivity of typical (T1-weighted neuroimaging to detect subcortical differences. To address this, we acquired both magnetisation transfer (MT saturation maps optimised for subcortical contrast, and conventional T1-weighted images in 30 adults with ADHD and 30 age, IQ, gender and handedness-matched controls. Using VBM of both datasets, we demonstrate volumetric reductions within the left ventral striatum on MT that are not observed on identically pre-processed T1-weighted images from the same participants. Nevertheless, both techniques reported similar sensitivity to cortical abnormalities in the right inferior parietal lobe. Additionally, we show that differences in striatal iron may potentially explain this reduced sensitivity of T1-weighted images in adults. Together, these findings indicate that prior VBM studies reporting no abnormalities in striatal volume in adult ADHD might have been compromised by the methodological insensitivity of T1-weighted VBM to subcortical differences, and that structural abnormalities of the striatum in ADHD do indeed persist into adulthood.

Discriminative Transfer Learning for General Image Restoration

KAUST Repository

Xiao, Lei; Heide, Felix; Heidrich, Wolfgang; Schö lkopf, Bernhard; Hirsch, Michael

2018-01-01

Recently, several discriminative learning approaches have been proposed for effective image restoration, achieving convincing trade-off between image quality and computational efficiency. However, these methods require separate training for each restoration task (e.g., denoising, deblurring, demosaicing) and problem condition (e.g., noise level of input images). This makes it time-consuming and difficult to encompass all tasks and conditions during training. In this paper, we propose a discriminative transfer learning method that incorporates formal proximal optimization and discriminative learning for general image restoration. The method requires a single-pass discriminative training and allows for reuse across various problems and conditions while achieving an efficiency comparable to previous discriminative approaches. Furthermore, after being trained, our model can be easily transferred to new likelihood terms to solve untrained tasks, or be combined with existing priors to further improve image restoration quality.

Discriminative Transfer Learning for General Image Restoration

KAUST Repository

Xiao, Lei

2018-04-30

Recently, several discriminative learning approaches have been proposed for effective image restoration, achieving convincing trade-off between image quality and computational efficiency. However, these methods require separate training for each restoration task (e.g., denoising, deblurring, demosaicing) and problem condition (e.g., noise level of input images). This makes it time-consuming and difficult to encompass all tasks and conditions during training. In this paper, we propose a discriminative transfer learning method that incorporates formal proximal optimization and discriminative learning for general image restoration. The method requires a single-pass discriminative training and allows for reuse across various problems and conditions while achieving an efficiency comparable to previous discriminative approaches. Furthermore, after being trained, our model can be easily transferred to new likelihood terms to solve untrained tasks, or be combined with existing priors to further improve image restoration quality.

On the role of the magnetic tension during the gravitational collapse of a magnetised fluid

International Nuclear Information System (INIS)

Tsagas, Christos G

2005-01-01

We investigate the physics of magnetised gravitational collapse by studying the behaviour of a timelike congruence of non-geodesic worldlines in the presence of a magnetic field. We show that the general relativistic coupling between magnetism and geometry, and the tension properties of the field, lead to magneto-curvature stresses that resist the collapse. When these tension stresses dominate, they can prevent an initially converging family of non-geodesic worldlines from focusing without violating the standard energy conditions

Past, present, and future of sublimation transfer imaging

Science.gov (United States)

Akada, Masanori

1990-07-01

SONY's announcement of tlavica system shaked the world in 1981. In the new nonphotographic imaging system, image is acquired with CCD to be converted into electric image-signal, stored in magnetic recording media,displayed on a CR1 and printed on a special sheet. To get a hard copy, Sublimation Transfer technology was developed. That announcement brought about world-wide R&D of competitive color imaging systems: Ink-jet, Wax transfer,. Sublimation Transfer(ST) and Electrophotography. In spite of much effort,most of those were insufficient for getting a good hard copy. Developing sufficient ST recording media, Dai Nippon Printing started ST recording media business in 1986. It was the first manufacturing scale production and sale of ST recording media in the world. Nowadays ST technology is known for its advantages: high image quality, consistency from copy to copy, smooth tone-reproduction from high-light to maximum density, and easiness to use. In the following paper progress of ST recording media and the present situation and future markets of the media will be presented.

Amide Proton Transfer (APT) MR imaging and Magnetization Transfer (MT) MR imaging of pediatric brain development

International Nuclear Information System (INIS)

Zhang, Hong; Kang, Huiying; Peng, Yun; Zhao, Xuna; Jiang, Shanshan; Zhang, Yi; Zhou, Jinyuan

2016-01-01

To quantify the brain maturation process during childhood using combined amide proton transfer (APT) and conventional magnetization transfer (MT) imaging at 3 Tesla. Eighty-two neurodevelopmentally normal children (44 males and 38 females; age range, 2-190 months) were imaged using an APT/MT imaging protocol with multiple saturation frequency offsets. The APT-weighted (APTW) and MT ratio (MTR) signals were quantitatively analyzed in multiple brain areas. Age-related changes in MTR and APTW were evaluated with a non-linear regression analysis. The APTW signals followed a decreasing exponential curve with age in all brain regions measured (R"2 = 0.7-0.8 for the corpus callosum, frontal and occipital white matter, and centrum semiovale). The most significant changes appeared within the first year. At maturation, larger decreases in APTW and lower APTW values were found in the white matter. On the contrary, the MTR signals followed an increasing exponential curve with age in the same brain regions measured, with the most significant changes appearing within the initial 2 years. There was an inverse correlation between the MTR and APTW signal intensities during brain maturation. Together with MT imaging, protein-based APT imaging can provide additional information in assessing brain myelination in the paediatric population. (orig.)

Amide Proton Transfer (APT) MR imaging and Magnetization Transfer (MT) MR imaging of pediatric brain development

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hong; Kang, Huiying; Peng, Yun [Beijing Children' s Hospital, Capital Medical University, Imaging Center, Department of Radiology, Beijing (China); Zhao, Xuna [Philips Healthcare, Beijing (China); Jiang, Shanshan; Zhang, Yi; Zhou, Jinyuan [Johns Hopkins University, Division of MR Research, Department of Radiology, Baltimore, MD (United States)

2016-10-15

To quantify the brain maturation process during childhood using combined amide proton transfer (APT) and conventional magnetization transfer (MT) imaging at 3 Tesla. Eighty-two neurodevelopmentally normal children (44 males and 38 females; age range, 2-190 months) were imaged using an APT/MT imaging protocol with multiple saturation frequency offsets. The APT-weighted (APTW) and MT ratio (MTR) signals were quantitatively analyzed in multiple brain areas. Age-related changes in MTR and APTW were evaluated with a non-linear regression analysis. The APTW signals followed a decreasing exponential curve with age in all brain regions measured (R{sup 2} = 0.7-0.8 for the corpus callosum, frontal and occipital white matter, and centrum semiovale). The most significant changes appeared within the first year. At maturation, larger decreases in APTW and lower APTW values were found in the white matter. On the contrary, the MTR signals followed an increasing exponential curve with age in the same brain regions measured, with the most significant changes appearing within the initial 2 years. There was an inverse correlation between the MTR and APTW signal intensities during brain maturation. Together with MT imaging, protein-based APT imaging can provide additional information in assessing brain myelination in the paediatric population. (orig.)

Magnetization transfer MR of cerebrovascular disorders using calculated images

Energy Technology Data Exchange (ETDEWEB)

Enomoto, Kyoko; Watabe, Tsuneya; Amanuma, Makoto; Heshiki, Atsuko [Saitama Medical School, Moroyama, Saitama (Japan)

1997-06-01

This study applied a magnetization transfer contrast method to patients with cerebrovascular disorders. A 1.5 T superconducting MR unit was used, and magnetization transfer ratio (MTR) images were calculated by evaluating two paired images before and after off-resonance gradient echo pulse sequences. The normal white matter showed the highest MTRs, CSF the lowest, and gray matter, intermediate. Cerebral ischemic patients showed two patterns according to the chronological stage of the affected area. Lesions in the acute and subacute stages revealed higher transfer rates than those in the chronic stage. Patients with cerebral hemorrhage were divided into three groups: the hyperacute group showed a low transfer pattern; the acute group presented inhomogeneous high transfer rates; and the subacute group showed remarkably low transfer rates. In the acute and subacute ischemic stages, increased macromolecules caused higher MTRs than in the chronic stage. In hemorrhagic groups, low MTRs in subacute hemorrhage reflected the transfer of methemoglobin. High MTRs in acute hemorrhage with rich deoxyhemoglobin suggested increased fibrin, plasma, and serum components of macromolecules. The MTC method provided new chronological information on cerebral hemorrhage, adding to that provided by routine MR images. (author)

Performance assessment of imaging plates for the JHR transfer Neutron Imaging System

Science.gov (United States)

Simon, E.; Guimbal, P. AB(; )

2018-01-01

The underwater Neutron Imaging System to be installed in the Jules Horowitz Reactor (JHR-NIS) is based on a transfer method using a neutron activated beta-emitter like Dysprosium. The information stored in the converter is to be offline transferred on a specific imaging system, still to be defined. Solutions are currently under investigation for the JHR-NIS in order to anticipate the disappearance of radiographic films commonly used in these applications. We report here the performance assessment of Computed Radiography imagers (Imaging Plates) performed at LLB/Orphée (CEA Saclay). Several imaging plate types are studied, in one hand in the configuration involving an intimate contact with an activated dysprosium foil converter: Fuji BAS-TR, Fuji UR-1 and Carestream Flex XL Blue imaging plates, and in the other hand by using a prototypal imaging plate doped with dysprosium and thus not needing any contact with a separate converter foil. The results for these imaging plates are compared with those obtained with gadolinium doped imaging plate used in direct neutron imaging (Fuji BAS-ND). The detection performances of the different imagers are compared regarding resolution and noise. The many advantages of using imaging plates over radiographic films (high sensitivity, linear response, high dynamic range) could palliate its lower intrinsic resolution.

Pediatric Trauma Transfer Imaging Inefficiencies-Opportunities for Improvement with Cloud Technology.

Science.gov (United States)

Puckett, Yana; To, Alvin

2016-01-01

This study examines the inefficiencies of radiologic imaging transfers from one hospital to the other during pediatric trauma transfers in an era of cloud based information sharing. Retrospective review of all patients transferred to a pediatric trauma center from 2008-2014 was performed. Imaging was reviewed for whether imaging accompanied the patient, whether imaging was able to be uploaded onto computer for records, whether imaging had to be repeated, and whether imaging obtained at outside hospitals (OSH) was done per universal pediatric trauma guidelines. Of the 1761 patients retrospectively reviewed, 559 met our inclusion criteria. Imaging was sent with the patient 87.7% of the time. Imaging was unable to be uploaded 31.9% of the time. CT imaging had to be repeated 1.8% of the time. CT scan was not done per universal pediatric trauma guidelines 1.2% of the time. Our study demonstrated that current imaging transfer is inefficient, leads to excess ionizing radiation, and increased healthcare costs. Universal implementation of cloud based radiology has the potential to eliminate excess ionizing radiation to children, improve patient care, and save cost to healthcare system.

Pediatric Trauma Transfer Imaging Inefficiencies—Opportunities for Improvement with Cloud Technology

Directory of Open Access Journals (Sweden)

Yana Puckett

2016-02-01

Full Text Available BACKGROUND: This study examines the inefficiencies of radiologic imaging transfers from one hospital to the other during pediatric trauma transfers in an era of cloud based information sharing. METHODS: Retrospective review of all patients transferred to a pediatric trauma center from 2008–2014 was performed. Imaging was reviewed for whether imaging accompanied the patient, whether imaging was able to be uploaded onto computer for records, whether imaging had to be repeated, and whether imaging obtained at outside hospitals (OSH was done per universal pediatric trauma guidelines. RESULTS: Of the 1761 patients retrospectively reviewed, 559 met our inclusion criteria. Imaging was sent with the patient 87.7% of the time. Imaging was unable to be uploaded 31.9% of the time. CT imaging had to be repeated 1.8% of the time. CT scan was not done per universal pediatric trauma guidelines 1.2% of the time. CONCLUSION: Our study demonstrated that current imaging transfer is inefficient, leads to excess ionizing radiation, and increased healthcare costs. Universal implementation of cloud based radiology has the potential to eliminate excess ionizing radiation to children, improve patient care, and save cost to healthcare system.

Visualisation of subchondral erosion in rat monoarticular arthritis by magnetic resonance imaging

International Nuclear Information System (INIS)

Carpenter, T.A.; Everett, J.R.; Hall, L.D.; Harper, G.P.; Hodgson, R.J.; James, M.F.

1995-01-01

High-resolution magnetic resonance imaging (MRI) was used to investigate antigen-induced monoarticular arthritis (AIMA) in the rat. In sagittal, spin-echo images of the knee, characteristic parallel bands, in the order dark-light-dark, were consistently observed 5-8 days after arthritis induction; the bands ran concentric with, and just beneath, the femoral and tibial articular surfaces. Concurrent radiology, histology and MRI (chemical shift-selective imaging and contrast enhancement with magnetisation transfer and gadolinium) established that the phenomenon reflected subchondral erosion, not artefact. The outer hypointense band corresponded to calcified cartilage underlying the articular surface. The central hyperintense band reflected inflammatory matrix displacing normal haematopoietic tissue immediately subchondrally; here, trabecular bone had mostly disappeared, but adjacent articular cartilage, although under attack and lacking proteoglycan, appeared structurally normal. The inner hypointense band reflected deeper, truncated trabeculae within inflammatory matrix, layered with pallisading osteoblast-like cells. This study exemplifies the power of MRI for revealing localised joint pathology non-invasively, and shows that rat AIMA shares many pathological features with arthritis in human beings. (orig.)

DyNi2Mn—magnetisation and Mössbauer spectroscopy

International Nuclear Information System (INIS)

Wang Jianli; Campbell, Stewart James; Kennedy, Shane Joseph; Dou Shixue; Wu Guangheng

2012-01-01

The physical properties of DyNi 2 Mn doped with 57 Fe have been investigated by X-ray diffraction, magnetisation (10–300 K) and 57 Fe Mössbauer spectroscopy measurements (5–300 K). DyNi 2 Mn( 57 Fe) crystallizes in the MgCu 2 -type cubic structure (Fd   −3m space group). The ordering temperature is found to be T C  = 99(2) K, much higher than those of DyNi 2 (∼22 K) and DyMn 2 (∼35 K). Analyses of isothermal M–H curves and the related Arrott plots confirm that the magnetic phase transition at T C is second order. The magnetic entropy change around T C is 4.0 J/kg K for a magnetic field change of 0 T to 5 T. The spectra above T C exhibit features consistent with quadrupolar effects while below T C the spectra exhibit magnetic hyperfine splitting. The Debye temperature for DyNi 2 Mn has been determined as θ D  = 200(20) K from a fit to the variable temperature isomer shift IS(T).

DyNi{sub 2}Mn-magnetisation and Moessbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Wang Jianli; Campbell, Stewart James, E-mail: stewart.campbell@adfa.edu.au [University of New South Wales, School of Physical, Environmental and Mathematical Sciences (Australia); Kennedy, Shane Joseph [ANSTO, Bragg Institute (Australia); Dou Shixue [University of Wollongong, Institute for Superconductivity and Electronic Materials (Australia); Wu Guangheng [Chinese Academy of Science, Institute of Physics (China)

2012-03-15

The physical properties of DyNi{sub 2}Mn doped with {sup 57}Fe have been investigated by X-ray diffraction, magnetisation (10-300 K) and {sup 57}Fe Moessbauer spectroscopy measurements (5-300 K). DyNi{sub 2}Mn({sup 57}Fe) crystallizes in the MgCu{sub 2}-type cubic structure (Fd{sup }-3m space group). The ordering temperature is found to be T{sub C} = 99(2) K, much higher than those of DyNi{sub 2} ({approx}22 K) and DyMn{sub 2} ({approx}35 K). Analyses of isothermal M-H curves and the related Arrott plots confirm that the magnetic phase transition at T{sub C} is second order. The magnetic entropy change around T{sub C} is 4.0 J/kg K for a magnetic field change of 0 T to 5 T. The spectra above T{sub C} exhibit features consistent with quadrupolar effects while below T{sub C} the spectra exhibit magnetic hyperfine splitting. The Debye temperature for DyNi{sub 2}Mn has been determined as {theta}{sub D} = 200(20) K from a fit to the variable temperature isomer shift IS(T).

Image transfer by cascaded stack of photonic crystal and air layers

NARCIS (Netherlands)

Shen, C.; Michielsen, K.; Raedt, H. De

2006-01-01

We demonstrate image transfer by a cascaded stack consisting of two and three triangular-lattice photonic crystal slabs separated by air. The quality of the image transfered by the stack is sensitive to the air/photonic crystal interface termination and the frequency. Depending on the frequency and

High-resolution magnetic resonance imaging of arthritic pathology in the rat knee

Energy Technology Data Exchange (ETDEWEB)

Carpenter, T.A. (Herchel Smith Lab. for Medicinal Chemistry, Cambridge Univ. (United Kingdom)); Everett, J.R. (Smith Kline Beecham Pharmaceuticals, Betchworth (United Kingdom)); Hall, L.D. (Herchel Smith Lab. for Medicinal Chemistry, Cambridge Univ. (United Kingdom)); Harper, G.P. (Smith Kline Beecham Pharmaceuticals, Welwyn (United Kingdom)); Hodgson, R.J. (Herchel Smith Lab. for Medicinal Chemistry, Cambridge Univ. (United Kingdom)); James, M.F. (Smith Kline Beecham Pharmaceuticals, Harlow (United Kingdom)); Watson, P.J. (Herchel Smith Lab. for Medicinal Chemistry, Cambridge Univ. (United Kingdom))

1994-08-01

High-resolution magnetic resonance imaging (MRI) has been used to visualise the changes that occur in both soft tissue and bone during antigen-induced, monoarticular arthritis (AIMA) of the rat knee. Extensive optimisation studies were performed in order to minimise the time of the experiments and to maximise both the signal-to-noise ratio and the contrast in the MR images. The study was cross-sectional rather than longitudinal and at each of the 13 time points studied during the progression of the disease, corresponding X-radiographs and histological sections were obtained. Interpretation of the spin echo MR images was aided by the use of chemical shift-selective imaging, magnetisation transfer contrast and relaxation time experiments, as well as by correlation with the histology and X-radiography data. The MR images clearly show invasion of the synovium by an inflammatory pannus which spreads over the articular cartilage and invades the bone, leading to erosion and later remodelling. Two distinct types of bony erosion were observed: focal erosions, especially at the margins of the joint, and subchondral erosions. It is concluded that MRI provides a sensitive, non-invasive method for investigating both early-stage inflammatory changes and late-stage bony changes in the knee joints of the arthritic rat. (orig.)

High-resolution magnetic resonance imaging of arthritic pathology in the rat knee

International Nuclear Information System (INIS)

Carpenter, T.A.; Everett, J.R.; Hall, L.D.; Harper, G.P.; Hodgson, R.J.; James, M.F.; Watson, P.J.

1994-01-01

High-resolution magnetic resonance imaging (MRI) has been used to visualise the changes that occur in both soft tissue and bone during antigen-induced, monoarticular arthritis (AIMA) of the rat knee. Extensive optimisation studies were performed in order to minimise the time of the experiments and to maximise both the signal-to-noise ratio and the contrast in the MR images. The study was cross-sectional rather than longitudinal and at each of the 13 time points studied during the progression of the disease, corresponding X-radiographs and histological sections were obtained. Interpretation of the spin echo MR images was aided by the use of chemical shift-selective imaging, magnetisation transfer contrast and relaxation time experiments, as well as by correlation with the histology and X-radiography data. The MR images clearly show invasion of the synovium by an inflammatory pannus which spreads over the articular cartilage and invades the bone, leading to erosion and later remodelling. Two distinct types of bony erosion were observed: focal erosions, especially at the margins of the joint, and subchondral erosions. It is concluded that MRI provides a sensitive, non-invasive method for investigating both early-stage inflammatory changes and late-stage bony changes in the knee joints of the arthritic rat. (orig.)

Inelastic Neutron Scattering and Magnetisation Investigation of an Exchange-Coupled Dy2 SMM

Science.gov (United States)

Baker, Michael L.; Zhang, Qing; Sarachik, Myriam P.; Kent, Andrew D.; Chen, Yizhang; Butch, Nicholas; Pineda, Eufemio M.; McInnes, Eric

The strong spin orbit coupling and weak crystal field energies of simple exchange-coupled rare earth SMMs makes the precise evaluation of their magnetic properties nontrivial. Here we report a detailed investigation of the single molecule magnet hqH2Dy2(hq)4(NO3)3MeOH. Inelastic neutron scattering is used to obtain direct access to several low energy crystal field excitations. The INS results display several features that are not found in earlier FIR absorption experiments, while other features found in the latter are absent. Based on the effective point charge model, numerical calculations are currently underway to resolve these apparent discrepancies using complementary magnetisation measurements to resolve the exchange between Dy ions. Work supported by ARO W911NF-13-1-1025 (CCNY) and NSF-DMR-1309202 (NYU).

Competing exchange interactions and their relevance for the magnetisation process in RMn6-xCrxSn6 powders (R=Y, Gd, Tb, Dy, Ho, Er)

International Nuclear Information System (INIS)

Brabers, J.H.V.J.; Zhou, G.F.; Colpa, J.H.P.; Buschow, K.H.J.; De Boer, F.R.

1994-01-01

The free-powder magnetisation of RMn 6-x Cr x Sn 6 compounds has been measured for compounds with R=Y, Gd, Tb, Dy, Ho, Er in fields up to 38 T, and interpreted in terms of a simple model, which is also outlined in this paper. From the measurements, estimates for the R-3d mean-field coupling constant (n RT ) could be derived for the cases where R=Gd, Tb, Dy, Ho, Er. In turn, the n RT values can be related to the microscopic spin-coupling constant (J RT ). In the case of YMn 6 Sn 6 the high-field measurement presents evidence for a very weak antiferromagnetic coupling between the Mn layers. Furthermore, values for the Mn moments (μ Mn ) were also derived from the magnetisation measurements. The estimated μ Mn values are of the order of 2.0 μ B . ((orig.))

Image transfer with spatial coherence for aberration corrected transmission electron microscopes

International Nuclear Information System (INIS)

Hosokawa, Fumio; Sawada, Hidetaka; Shinkawa, Takao; Sannomiya, Takumi

2016-01-01

The formula of spatial coherence involving an aberration up to six-fold astigmatism is derived for aberration-corrected transmission electron microscopy. Transfer functions for linear imaging are calculated using the newly derived formula with several residual aberrations. Depending on the symmetry and origin of an aberration, the calculated transfer function shows characteristic symmetries. The aberrations that originate from the field’s components, having uniformity along the z direction, namely, the n-fold astigmatism, show rotational symmetric damping of the coherence. The aberrations that originate from the field’s derivatives with respect to z, such as coma, star, and three lobe, show non-rotational symmetric damping. It is confirmed that the odd-symmetric wave aberrations have influences on the attenuation of an image via spatial coherence. Examples of image simulations of haemoglobin and Si [211] are shown by using the spatial coherence for an aberration-corrected electron microscope. - Highlights: • The formula of partial coherence for aberration corrected TEM is derived. • Transfer functions are calculated with several residual aberrations. • The calculated transfer function shows the characteristic damping. • The odd-symmetric wave aberrations can cause the attenuation of image via coherence. • The examples of aberration corrected TEM image simulations are shown.

Image transfer with spatial coherence for aberration corrected transmission electron microscopes

Energy Technology Data Exchange (ETDEWEB)

Hosokawa, Fumio, E-mail: hosokawa@bio-net.co.jp [BioNet Ltd., 2-3-28 Nishikityo, Tachikwa, Tokyo (Japan); Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8503 (Japan); Sawada, Hidetaka [JEOL (UK) Ltd., JEOL House, Silver Court, Watchmead, Welwyn Garden City, Herts AL7 1LT (United Kingdom); Shinkawa, Takao [BioNet Ltd., 2-3-28 Nishikityo, Tachikwa, Tokyo (Japan); Sannomiya, Takumi [Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8503 (Japan)

2016-08-15

The formula of spatial coherence involving an aberration up to six-fold astigmatism is derived for aberration-corrected transmission electron microscopy. Transfer functions for linear imaging are calculated using the newly derived formula with several residual aberrations. Depending on the symmetry and origin of an aberration, the calculated transfer function shows characteristic symmetries. The aberrations that originate from the field’s components, having uniformity along the z direction, namely, the n-fold astigmatism, show rotational symmetric damping of the coherence. The aberrations that originate from the field’s derivatives with respect to z, such as coma, star, and three lobe, show non-rotational symmetric damping. It is confirmed that the odd-symmetric wave aberrations have influences on the attenuation of an image via spatial coherence. Examples of image simulations of haemoglobin and Si [211] are shown by using the spatial coherence for an aberration-corrected electron microscope. - Highlights: • The formula of partial coherence for aberration corrected TEM is derived. • Transfer functions are calculated with several residual aberrations. • The calculated transfer function shows the characteristic damping. • The odd-symmetric wave aberrations can cause the attenuation of image via coherence. • The examples of aberration corrected TEM image simulations are shown.

Conjugate Image Theory Applied on Capacitive Wireless Power Transfer

OpenAIRE

Ben Minnaert; Nobby Stevens

2017-01-01

Wireless power transfer using a magnetic field through inductive coupling is steadily entering the market in a broad range of applications. However, for certain applications, capacitive wireless power transfer using electric coupling might be preferable. In order to obtain a maximum power transfer efficiency, an optimal compensation network must be designed at the input and output ports of the capacitive wireless link. In this work, the conjugate image theory is applied to determine this opti...

Transfer function analysis of positron-emitting tracer imaging system (PETIS) data

International Nuclear Information System (INIS)

Keutgen, N.; Matsuhashi, S.; Mizuniwa, C.; Ito, T.; Fujimura, T.; Ishioka, N.S.; Watanabe, S.; Sekine, T.; Uchida, H.; Hashimoto, S.

2002-01-01

Quantitative analysis of the two-dimensional image data obtained with the positron-emitting tracer imaging system (PETIS) for plant physiology has been carried out using a transfer function analysis method. While a cut leaf base of Chinese chive (Allium tuberosum Rottler) or a cut stem of soybean (Glycine max L.) was immersed in an aqueous solution containing the [ 18 F] F - ion or [ 13 N]NO 3 - ion, tracer images of the leaf of Chinese chive and the trifoliate of soybean were recorded with PETIS. From the time sequence of images, the tracer transfer function was estimated from which the speed of tracer transport and the fraction moved between specified image positions were deduced

Gene transfer strategies for improving radiolabeled peptide imaging and therapy

International Nuclear Information System (INIS)

Rogers, B.E.; Buchsbaum, D.J.; Zinn, K.R.

2000-01-01

Utilization of molecular biology techniques offers attractive options in nuclear medicine for improving cancer imaging and therapy with radiolabeled peptides. Two of these options include utilization of phage-panning to identify novel tumor specific peptides or single chain antibodies and gene transfer techniques to increase the antibodies and gene transfer techniques to increase the number of antigen/receptor sites expressed on malignant cells. The group has focused on the latter approach for improving radiolabeled peptide imaging and therapy. The most widely used gene transfer vectors in clinical gene therapy trials include retrovirus, cationic lipids and adenovirus. It has been utilized adenovirus vectors for gene transfer because of their ability to accomplish efficient in vivo gene transfer. Adenovirus vectors encoding the genes for a variety of antigens/receptors (carcinoembryonic antigen, gastrin-releasing peptide receptor, somatostatin receptor subtype 2 (SSTr2) have all shown that their expression is increased on cancer cells both in vitro and in vivo following adenovirus infection. Of particular interest has been the adenovirus encoding for SSTr2 (AdCMVSSTr2). Various radioisotopes have been attached to somatostatin analogues for imaging and therapy of SSTr2-positive tumors both clinically and in animal models. The use of these analogues in combination with AdCMVSSTr2 is a promising approach for improving the detection sensitivity and therapeutic efficacy of these radiolabeled peptides against solid tumors. In addition, it has been proposed the use of SSTr2 as a marker for imaging the expression of another cancer therapeutic transgene (e.g. cytosine deaminase, thymidine kinase) encoded within the same vector. This would allow for non-invasive monitoring of gene delivery to tumor sites

Soil transference patterns on bras: Image processing and laboratory dragging experiments.

Science.gov (United States)

Murray, Kathleen R; Fitzpatrick, Robert W; Bottrill, Ralph S; Berry, Ron; Kobus, Hilton

2016-01-01

In a recent Australian homicide, trace soil on the victim's clothing suggested she was initially attacked in her front yard and not the park where her body was buried. However the important issue that emerged during the trial was how soil was transferred to her clothing. This became the catalyst for designing a range of soil transference experiments (STEs) to study, recognise and classify soil patterns transferred onto fabric when a body is dragged across a soil surface. Soil deposits of interest in this murder were on the victim's bra and this paper reports the results of anthropogenic soil transfer to bra-cups and straps caused by dragging. Transfer patterns were recorded by digital photography and photomicroscopy. Eight soil transfer patterns on fabric, specific to dragging as the transfer method, appeared consistently throughout the STEs. The distinctive soil patterns were largely dependent on a wide range of soil features that were measured and identified for each soil tested using X-ray Diffraction and Non-Dispersive Infra-Red analysis. Digital photographs of soil transfer patterns on fabric were analysed using image processing software to provide a soil object-oriented classification of all soil objects with a diameter of 2 pixels and above transferred. Although soil transfer patterns were easily identifiable by naked-eye alone, image processing software provided objective numerical data to support this traditional (but subjective) interpretation. Image software soil colour analysis assigned a range of Munsell colours to identify and compare trace soil on fabric to other trace soil evidence from the same location; without requiring a spectrophotometer. Trace soil from the same location was identified by linking soils with similar dominant and sub-dominant Munsell colour peaks. Image processing numerical data on the quantity of soil transferred to fabric, enabled a relationship to be discovered between soil type, clay mineralogy (smectite), particle size and

The Effect of Crystal Packing and Re(IV) Ions on the Magnetisation Relaxation of [Mn6 ]-Based Molecular Magnets

OpenAIRE

Martínez-Lillo, José; Cano, Joan; Wernsdorfer, Wolfgang; Brechin, Euan K

2015-01-01

The energy barrier to magnetisation relaxation in single-molecule magnets (SMMs) proffers potential technological applications in high-density information storage and quantum computation. Leading candidates amongst complexes of 3d metals ions are the hexametallic family of complexes of formula [Mn6 O2 (R-sao)6 (X)2 (solvent)y ] (saoH2 =salicylaldoxime; X=mono-anion; y=4-6; R=H, Me, Et, and Ph). The recent synthesis of cationic [Mn6 ][ClO4 ]2 family members, in which the coordinating X ions we...

Modulation transfer function cascade model for a sampled IR imaging system.

Science.gov (United States)

de Luca, L; Cardone, G

1991-05-01

The performance of the infrared scanning radiometer (IRSR) is strongly stressed in convective heat transfer applications where high spatial frequencies in the signal that describes the thermal image are present. The need to characterize more deeply the system spatial resolution has led to the formulation of a cascade model for the evaluation of the actual modulation transfer function of a sampled IR imaging system. The model can yield both the aliasing band and the averaged modulation response for a general sampling subsystem. For a line scan imaging system, which is the case of a typical IRSR, a rule of thumb that states whether the combined sampling-imaging system is either imaging-dependent or sampling-dependent is proposed. The model is tested by comparing it with other noncascade models as well as by ad hoc measurements performed on a commercial digitized IRSR.

Fe/V and Fe/Co (0 0 1) superlattices: growth, anisotropy, magnetisation and magnetoresistance

International Nuclear Information System (INIS)

Nordblad, P.; Broddefalk, A.; Mathieu, R.; Blomqvist, P.; Eriksson, O.; Waeppling, R.

2003-01-01

Some physical properties of BCC Fe/V and Fe/Co (0 0 1) superlattices are reviewed. The dependence of the magnetic anisotropy on the in-plane strain introduced by the lattice mismatch between Fe and V is measured and compared to a theoretical derivation. The dependence of the magnetic anisotropy (and saturation magnetisation) on the layer thickness ratio Fe/Co is measured and a value for the anisotropy of BCC Co is derived from extrapolation. The interlayer exchange coupling of Fe/V superlattices is studied as a function of the V layer thickness (constant Fe thickness) and layer thickness of Fe (constant V thickness). A region of antiferromagnetic coupling and GMR is found for V thicknesses 12-14 monolayers. However, surprisingly, a 'cutoff' of the antiferromagnetic coupling and GMR is found when the iron layer thickness exceeds about 10 monolayers

Modelling of isothermal remanence magnetisation curves for an assembly of macrospins

International Nuclear Information System (INIS)

Tournus, F.

2015-01-01

We present a robust and efficient framework to compute isothermal remanent magnetisation (IRM) curves for magnetic nanoparticle assemblies. The assembly is modelled by independent, randomly oriented, uniaxial macrospins and we use a Néel model to take into account the thermal relaxation. A simple analytic expression is established for a single size, in a sudden switching approximation, and is compared to more evolved models. We show that for realistic samples (necessarily presenting a size dispersion) the simple model is very satisfactory. With this framework, it is then possible to reliably simulate IRM curves, which can be compared to experimental measurements and used in a best fit procedure. We also examine the influence of several parameters on the IRM curves and we discuss the link between the irreversible susceptibility and the switching field distribution. - Highlights: • A framework to compute IRM curves for nanoparticle assemblies is presented. • A simple analytic expression (for a single size) is compared to more evolved models. • The simple expression can reliably simulate IRM curves for realistic samples. • Irreversible susceptibility and the influence of several parameters is discussed

Fluorescence resonance energy transfer imaging of CFP/YFP labeled NDH in cyanobacterium cell

International Nuclear Information System (INIS)

Ji Dongmei; Lv Wei; Huang Zhengxi; Xia Andong; Xu Min; Ma Weimin; Mi Hualing; Ogawa Teruo

2007-01-01

The laser confocal scanning microscopy combined with time-correlated single photon counting imaging technique to obtain fluorescence intensity and fluorescence lifetime images for fluorescence resonance energy transfer measurement is reported. Both the fluorescence lifetime imaging microscopy (FLIM) and intensity images show inhomogeneous cyan fluorescent protein and yellow fluorescent protein (CFP /YFP) expression or inhomogeneous energy transfer between CFP and YFP over whole cell. The results presented in this work show that FLIM could be a potential method to reveal the structure-function behavior of NAD(P)H dehydrogenase complexes in living cell

Characterisation of a CMOS charge transfer device for TDI imaging

International Nuclear Information System (INIS)

Rushton, J.; Holland, A.; Stefanov, K.; Mayer, F.

2015-01-01

The performance of a prototype true charge transfer imaging sensor in CMOS is investigated. The finished device is destined for use in TDI applications, especially Earth-observation, and to this end radiation tolerance must be investigated. Before this, complete characterisation is required. This work starts by looking at charge transfer inefficiency and then investigates responsivity using mean-variance techniques

Conjugate Image Theory Applied on Capacitive Wireless Power Transfer

Directory of Open Access Journals (Sweden)

Ben Minnaert

2017-01-01

Full Text Available Wireless power transfer using a magnetic field through inductive coupling is steadily entering the market in a broad range of applications. However, for certain applications, capacitive wireless power transfer using electric coupling might be preferable. In order to obtain a maximum power transfer efficiency, an optimal compensation network must be designed at the input and output ports of the capacitive wireless link. In this work, the conjugate image theory is applied to determine this optimal network as a function of the characteristics of the capacitive wireless link, as well for the series as for the parallel topology. The results are compared with the inductive power transfer system. Introduction of a new concept, the coupling function, enables the description of the compensation network of both an inductive and a capacitive system in two elegant equations, valid for the series and the parallel topology. This approach allows better understanding of the fundamentals of the wireless power transfer link, necessary for the design of an efficient system.

Telemedicine using an image transfer system in the treatment of neurosurgical emergent cases

International Nuclear Information System (INIS)

Saito, Atsushi; Numagami, Yoshihiro; Kamiyama, Hironaga; Furuno, Yuuichi; Nishimura, Shinjitsu; Nishijima, Michiharu

2007-01-01

Our department is located in the Tsugaru district, which is famous for heavy snow fall, and the small number of neurosurgeon centers in the urban areas leads to an inadequate distribution of neurosurgeons for patients in this region. Such geographical and social constraints have made it difficult to offer sufficient neurosurgical care to all patients in the region. We describe the usefulness of a telemedicine triage system using an image transfer system in the treatment of neurosurgical emergent cases. Image transfer systems have been installed at our hospital and 11 regional hospitals in the Tsugaru district, and have been utilized for teleconsultation regarding neurosurgical patients via transferred computed tomography images since 1989. Consultations regarding 2,858 cases were directed to our department between 1989 and 2006, including 1,615 cases of stroke, 869 cases of head trauma, 97 cases of brain tumor, and 277 cases with other disorders. 84% of subarachnoid hemorrhage cases and 22% of head trauma cases needed emergent transfer. The state of consciousness in intracerebral hemorrhage, and the state of consciousness and time of consultation in head trauma were statistically significant factors for emergent transfer. The presert telemedicine triage system was useful for ensuring correct diagnosis and appropriate primary neurosurgical care in the regional hospitals without neurosurgical units, resulting in a reinforcement of the relationships among the regional hospitals and the efficient transfer of emergent neurosurgical patients. (author)

Development of a system for transferring images via a network: supporting a regional liaison.

Science.gov (United States)

Mihara, Naoki; Manabe, Shiro; Takeda, Toshihiro; Shinichirou, Kitamura; Junichi, Murakami; Kouji, Kiso; Matsumura, Yasushi

2013-01-01

We developed a system that transfers images via network and started using them in our hospital's PACS (Picture Archiving and Communication Systems) in 2006. We are pleased to report that the system has been re-developed and has been running so that there will be a regional liaison in the future. It has become possible to automatically transfer images simply by selecting the destination hospital that is registered in advance at the relay server. The gateway of this system can send images to a multi-center, relay management server, which receives the images and resends them. This system has the potential to be useful for image exchange, and to serve as a regional medical liaison.

Information Recovery Algorithm for Ground Objects in Thin Cloud Images by Fusing Guide Filter and Transfer Learning

Directory of Open Access Journals (Sweden)

HU Gensheng

2018-03-01

Full Text Available Ground object information of remote sensing images covered with thin clouds is obscure. An information recovery algorithm for ground objects in thin cloud images is proposed by fusing guide filter and transfer learning. Firstly, multi-resolution decomposition of thin cloud target images and cloud-free guidance images is performed by using multi-directional nonsubsampled dual-tree complex wavelet transform. Then the decomposed low frequency subbands are processed by using support vector guided filter and transfer learning respectively. The decomposed high frequency subbands are enhanced by using modified Laine enhancement function. The low frequency subbands output by guided filter and those predicted by transfer learning model are fused by the method of selection and weighting based on regional energy. Finally, the enhanced high frequency subbands and the fused low frequency subbands are reconstructed by using inverse multi-directional nonsubsampled dual-tree complex wavelet transform to obtain the ground object information recovery images. Experimental results of Landsat-8 OLI multispectral images show that, support vector guided filter can effectively preserve the detail information of the target images, domain adaptive transfer learning can effectively extend the range of available multi-source and multi-temporal remote sensing images, and good effects for ground object information recover are obtained by fusing guide filter and transfer learning to remove thin cloud on the remote sensing images.

Deep Learning- and Transfer Learning-Based Super Resolution Reconstruction from Single Medical Image

Directory of Open Access Journals (Sweden)

YiNan Zhang

2017-01-01

Full Text Available Medical images play an important role in medical diagnosis and research. In this paper, a transfer learning- and deep learning-based super resolution reconstruction method is introduced. The proposed method contains one bicubic interpolation template layer and two convolutional layers. The bicubic interpolation template layer is prefixed by mathematics deduction, and two convolutional layers learn from training samples. For saving training medical images, a SIFT feature-based transfer learning method is proposed. Not only can medical images be used to train the proposed method, but also other types of images can be added into training dataset selectively. In empirical experiments, results of eight distinctive medical images show improvement of image quality and time reduction. Further, the proposed method also produces slightly sharper edges than other deep learning approaches in less time and it is projected that the hybrid architecture of prefixed template layer and unfixed hidden layers has potentials in other applications.

Solid-phase immunoradiometric assay for C-reactive protein using magnetisable cellulose particles

International Nuclear Information System (INIS)

Beer, F.C. de; Pepys, M.B.

1982-01-01

An immunoradiometric assay (IRMA) for C-reactive protein (CRP) was developed using magnetisable cellulose particles as the solid-phase support for anti-CRP antibodies. 125 I-labelled immunopurified anti-CRP antibody was used to quantitate the amount of CRP taken up by the solid phase. Unbound label was easily and rapidly removed by decantation after sedimenting the particles on a magnet. The assay could detect 1 μg CRP/l and had a range of up to 10 mg/l with the portion of the standard curve between 10 μg/l and 2-3 mg/l being linear. Fifty samples per hour could be processed manually from serum to CRP result with an intra-assay CV of 5.2% and an inter-assay CV of 10.0%, based on 5 replicates of 5 samples with CRP levels between 2 mg/l and 180 mg/l run in 5 separate assays. Fifty clinical samples were assayed in parallel with a standard electroimmunoassay and yielded a linear correlation coefficient (r) of 0.975 and a slope of 0.98. With its single, brief incubation step including all reagents and its simple phase separation procedure the present method may be the assay of choice when precise measurement of CRP concentrations is required rapidly. (Auth.)

Temperature dependence of the spontaneous magnetisation of ferromagnetic insulators: Does it obey the 3/2-5/2-β law?

International Nuclear Information System (INIS)

Kuz'min, M.D.; Tishin, A.M.

2005-01-01

Temperature dependence of the spontaneous magnetisation is analysed for three archetypal ferromagnetic insulators, EuS, EuO and CrBr 3 . The main point is the shape, rather than scale, of the curve M s (T). As far as the available data enable us to judge, this shape is adequately described by the simple ''3/2-5/2-β'' expression (m=[1-sτ 3/2 -(1-s)τ 5/2 ] β ), proposed previously for metallic ferromagnets, and depends on a single dimensionless parameter s. The lack of direct experimental data makes this conclusion a preliminary one. In order to resolve the question definitively, accurate magnetic measurements on single crystals are required as a matter of priority

Computer Software Configuration Item-Specific Flight Software Image Transfer Script Generator

Science.gov (United States)

Bolen, Kenny; Greenlaw, Ronald

2010-01-01

A K-shell UNIX script enables the International Space Station (ISS) Flight Control Team (FCT) operators in NASA s Mission Control Center (MCC) in Houston to transfer an entire or partial computer software configuration item (CSCI) from a flight software compact disk (CD) to the onboard Portable Computer System (PCS). The tool is designed to read the content stored on a flight software CD and generate individual CSCI transfer scripts that are capable of transferring the flight software content in a given subdirectory on the CD to the scratch directory on the PCS. The flight control team can then transfer the flight software from the PCS scratch directory to the Electronically Erasable Programmable Read Only Memory (EEPROM) of an ISS Multiplexer/ Demultiplexer (MDM) via the Indirect File Transfer capability. The individual CSCI scripts and the CSCI Specific Flight Software Image Transfer Script Generator (CFITSG), when executed a second time, will remove all components from their original execution. The tool will identify errors in the transfer process and create logs of the transferred software for the purposes of configuration management.

Amide proton transfer imaging of high intensity focused ultrasound-treated tumor tissue

NARCIS (Netherlands)

Hectors, S.J.C.G.; Jacobs, I.; Strijkers, G.J.; Nicolay, K.

2014-01-01

Purpose: In this study, the suitability of amide proton transfer (APT) imaging as a biomarker for the characterization of high intensity focused ultrasound (HIFU)-treated tumor tissue was assessed. Methods: APT imaging was performed on tumor-bearing mice before (n=15), directly after (n=15) and at 3

Amide Proton Transfer Imaging of High Intensity Focused Ultrasound-Treated Tumor Tissue

NARCIS (Netherlands)

Hectors, Stefanie J. C. G.; Jacobs, Igor; Strijkers, Gustav J.; Nicolay, Klaas

2014-01-01

PurposeIn this study, the suitability of amide proton transfer (APT) imaging as a biomarker for the characterization of high intensity focused ultrasound (HIFU)-treated tumor tissue was assessed. MethodsAPT imaging was performed on tumor-bearing mice before (n=15), directly after (n=15) and at 3

A novel permanently magnetised high gradient magnetic filter using assisted capture for fine particles

Energy Technology Data Exchange (ETDEWEB)

Watson, J.H.P. [Univ. of Southampton (United Kingdom)

1995-02-01

This paper describes the structure and properties of a novel permanently magnetised magnetic filter for fine friable radioactive material. Previously a filter was described and tested. This filter was designed so that the holes in the filter are left open as capture proceeds which means the pressure drop builds up only slowly. This filter is not suitable for friable composite particles which can be broken by mechanical forces. The structure of magnetic part of the second filter has been changed so as to strongly capture particles composed of fine particles weakly bound together which tend to break when captured. This uses a principle of assisted-capture in which coarse particles aid the capture of the fine fragments. The technique has the unfortunate consequence that the pressure drop across the filter rises faster as capture capture proceeds than the filter described previously. These filters have the following characteristics: (1) No external magnet is required. (2) No external power is required. (3) Small is size and portable. (4) Easily interchangeable. (5) Can be cleaned without demagnetising.

Viriato: a Fourier-Hermite spectral code for strongly magnetised fluid-kinetic plasma dynamics

Science.gov (United States)

Loureiro, Nuno; Dorland, William; Fazendeiro, Luis; Kanekar, Anjor; Mallet, Alfred; Zocco, Alessandro

2015-11-01

We report on the algorithms and numerical methods used in Viriato, a novel fluid-kinetic code that solves two distinct sets of equations: (i) the Kinetic Reduced Electron Heating Model equations [Zocco & Schekochihin, 2011] and (ii) the kinetic reduced MHD (KRMHD) equations [Schekochihin et al., 2009]. Two main applications of these equations are magnetised (Alfvnénic) plasma turbulence and magnetic reconnection. Viriato uses operator splitting to separate the dynamics parallel and perpendicular to the ambient magnetic field (assumed strong). Along the magnetic field, Viriato allows for either a second-order accurate MacCormack method or, for higher accuracy, a spectral-like scheme. Perpendicular to the field Viriato is pseudo-spectral, and the time integration is performed by means of an iterative predictor-corrector scheme. In addition, a distinctive feature of Viriato is its spectral representation of the parallel velocity-space dependence, achieved by means of a Hermite representation of the perturbed distribution function. A series of linear and nonlinear benchmarks and tests are presented, with focus on 3D decaying kinetic turbulence. Work partially supported by Fundação para a Ciência e Tecnologia via Grants UID/FIS/50010/2013 and IF/00530/2013.

Method for estimating modulation transfer function from sample images.

Science.gov (United States)

Saiga, Rino; Takeuchi, Akihisa; Uesugi, Kentaro; Terada, Yasuko; Suzuki, Yoshio; Mizutani, Ryuta

2018-02-01

The modulation transfer function (MTF) represents the frequency domain response of imaging modalities. Here, we report a method for estimating the MTF from sample images. Test images were generated from a number of images, including those taken with an electron microscope and with an observation satellite. These original images were convolved with point spread functions (PSFs) including those of circular apertures. The resultant test images were subjected to a Fourier transformation. The logarithm of the squared norm of the Fourier transform was plotted against the squared distance from the origin. Linear correlations were observed in the logarithmic plots, indicating that the PSF of the test images can be approximated with a Gaussian. The MTF was then calculated from the Gaussian-approximated PSF. The obtained MTF closely coincided with the MTF predicted from the original PSF. The MTF of an x-ray microtomographic section of a fly brain was also estimated with this method. The obtained MTF showed good agreement with the MTF determined from an edge profile of an aluminum test object. We suggest that this approach is an alternative way of estimating the MTF, independently of the image type. Copyright © 2017 Elsevier Ltd. All rights reserved.

Intelligent Image Recognition System for Marine Fouling Using Softmax Transfer Learning and Deep Convolutional Neural Networks

Directory of Open Access Journals (Sweden)

C. S. Chin

2017-01-01

Full Text Available The control of biofouling on marine vessels is challenging and costly. Early detection before hull performance is significantly affected is desirable, especially if “grooming” is an option. Here, a system is described to detect marine fouling at an early stage of development. In this study, an image of fouling can be transferred wirelessly via a mobile network for analysis. The proposed system utilizes transfer learning and deep convolutional neural network (CNN to perform image recognition on the fouling image by classifying the detected fouling species and the density of fouling on the surface. Transfer learning using Google’s Inception V3 model with Softmax at last layer was carried out on a fouling database of 10 categories and 1825 images. Experimental results gave acceptable accuracies for fouling detection and recognition.

Geodesic Flow Kernel Support Vector Machine for Hyperspectral Image Classification by Unsupervised Subspace Feature Transfer

Directory of Open Access Journals (Sweden)

Alim Samat

2016-03-01

Full Text Available In order to deal with scenarios where the training data, used to deduce a model, and the validation data have different statistical distributions, we study the problem of transformed subspace feature transfer for domain adaptation (DA in the context of hyperspectral image classification via a geodesic Gaussian flow kernel based support vector machine (GFKSVM. To show the superior performance of the proposed approach, conventional support vector machines (SVMs and state-of-the-art DA algorithms, including information-theoretical learning of discriminative cluster for domain adaptation (ITLDC, joint distribution adaptation (JDA, and joint transfer matching (JTM, are also considered. Additionally, unsupervised linear and nonlinear subspace feature transfer techniques including principal component analysis (PCA, randomized nonlinear principal component analysis (rPCA, factor analysis (FA and non-negative matrix factorization (NNMF are investigated and compared. Experiments on two real hyperspectral images show the cross-image classification performances of the GFKSVM, confirming its effectiveness and suitability when applied to hyperspectral images.

Process techniques of charge transfer time reduction for high speed CMOS image sensors

International Nuclear Information System (INIS)

Cao Zhongxiang; Li Quanliang; Han Ye; Qin Qi; Feng Peng; Liu Liyuan; Wu Nanjian

2014-01-01

This paper proposes pixel process techniques to reduce the charge transfer time in high speed CMOS image sensors. These techniques increase the lateral conductivity of the photo-generated carriers in a pinned photodiode (PPD) and the voltage difference between the PPD and the floating diffusion (FD) node by controlling and optimizing the N doping concentration in the PPD and the threshold voltage of the reset transistor, respectively. The techniques shorten the charge transfer time from the PPD diode to the FD node effectively. The proposed process techniques do not need extra masks and do not cause harm to the fill factor. A sub array of 32 × 64 pixels was designed and implemented in the 0.18 μm CIS process with five implantation conditions splitting the N region in the PPD. The simulation and measured results demonstrate that the charge transfer time can be decreased by using the proposed techniques. Comparing the charge transfer time of the pixel with the different implantation conditions of the N region, the charge transfer time of 0.32 μs is achieved and 31% of image lag was reduced by using the proposed process techniques. (semiconductor devices)

Chemical exchange saturation transfer MR imaging of Parkinson's disease at 3 Tesla

International Nuclear Information System (INIS)

Li, Chunmei; Peng, Shuai; Wang, Rui; Chen, Min; Chen, Haibo; Su, Wen; Zhao, Xuna; Zhou, Jinyuan

2014-01-01

To demonstrate the feasibility of using chemical exchange saturation transfer (CEST) imaging to detect Parkinson's disease (PD) in patients at 3 Tesla. Twenty-seven PD patients (17 men and 10 women; age range, 54-77 years) and 22 age-matched normal controls (13 men and 9 women; age range, 55-73 years) were examined on a 3-Tesla MRI system. Magnetization transfer spectra with 31 different frequency offsets (-6 to 6 ppm) were acquired at two transverse slices of the head, including the basal ganglia and midbrain. One-way analysis of variance tests was used to compare the differences in CEST imaging signals between PD patients and normal controls. Total CEST signal between the offsets of 0 and 4 ppm in the substantia nigra was significantly lower in PD patients than in normal controls (P = 0.006), which could be associated with the loss of dopaminergic neurons. Protein-based CEST imaging signals at the offset of 3.5 ppm in the globus pallidus, putamen and caudate were significantly increased in PD patients, compared to normal controls (P < 0.001, P = 0.003, P < 0.001, respectively). CEST imaging signals could potentially serve as imaging biomarkers to aid in the non-invasive molecular diagnosis of PD. (orig.)

Evaluation of biolistic gene transfer methods in vivo using non-invasive bioluminescent imaging techniques

Directory of Open Access Journals (Sweden)

Daniell Henry

2011-06-01

Full Text Available Abstract Background Gene therapy continues to hold great potential for treating many different types of disease and dysfunction. Safe and efficient techniques for gene transfer and expression in vivo are needed to enable gene therapeutic strategies to be effective in patients. Currently, the most commonly used methods employ replication-defective viral vectors for gene transfer, while physical gene transfer methods such as biolistic-mediated ("gene-gun" delivery to target tissues have not been as extensively explored. In the present study, we evaluated the efficacy of biolistic gene transfer techniques in vivo using non-invasive bioluminescent imaging (BLI methods. Results Plasmid DNA carrying the firefly luciferase (LUC reporter gene under the control of the human Cytomegalovirus (CMV promoter/enhancer was transfected into mouse skin and liver using biolistic methods. The plasmids were coupled to gold microspheres (1 μm diameter using different DNA Loading Ratios (DLRs, and "shot" into target tissues using a helium-driven gene gun. The optimal DLR was found to be in the range of 4-10. Bioluminescence was measured using an In Vivo Imaging System (IVIS-50 at various time-points following transfer. Biolistic gene transfer to mouse skin produced peak reporter gene expression one day after transfer. Expression remained detectable through four days, but declined to undetectable levels by six days following gene transfer. Maximum depth of tissue penetration following biolistic transfer to abdominal skin was 200-300 μm. Similarly, biolistic gene transfer to mouse liver in vivo also produced peak early expression followed by a decline over time. In contrast to skin, however, liver expression of the reporter gene was relatively stable 4-8 days post-biolistic gene transfer, and remained detectable for nearly two weeks. Conclusions The use of bioluminescence imaging techniques enabled efficient evaluation of reporter gene expression in vivo. Our results

Quantitative Magnetization Transfer Imaging in Human Brain at 3 T via Selective Inversion Recovery

OpenAIRE

Dortch, Richard D.; Li, Ke; Gochberg, Daniel F.; Welch, E. Brian; Dula, Adrienne N.; Tamhane, Ashish A.; Gore, John C.; Smith, Seth A.

2011-01-01

Quantitative magnetization transfer imaging yields indices describing the interactions between free water protons and immobile, macromolecular protons—including the macromolecular to free pool size ratio (PSR) and the rate of magnetization transfer between pools kmf. This study describes the first implementation of the selective inversion recovery quantitative magnetization transfer method on a clinical 3.0-T scanner in human brain in vivo. Selective inversion recovery data were acquired at 1...

Efficient nonlinear registration of 3D images using high order co-ordinate transfer functions.

Science.gov (United States)

Barber, D C

1999-01-01

There is an increasing interest in image registration for a variety of medical imaging applications. Image registration is achieved through the use of a co-ordinate transfer function (CTF) which maps voxels in one image to voxels in the other image, including in the general case changes in mapped voxel intensity. If images of the same subject are to be registered the co-ordinate transfer function needs to implement a spatial transformation consisting of a displacement and a rigid rotation. In order to achieve registration a common approach is to choose a suitable quality-of-registration measure and devise a method for the efficient generation of the parameters of the CTF which minimize this measure. For registration of images from different subjects more complex transforms are required. In general function minimization is too slow to allow the use of CTFs with more than a small number of parameters. However, provided the images are from the same modality and the CTF can be expanded in terms of an appropriate set of basis functions this paper will show how relatively complex CTFs can be used for registration. The use of increasingly complex CTFs to minimize the within group standard deviation of a set of normal single photon emission tomography brain images is used to demonstrate the improved registration of images from different subjects using CTFs of increasing complexity.

Smear correction of highly variable, frame-transfer CCD images with application to polarimetry.

Science.gov (United States)

Iglesias, Francisco A; Feller, Alex; Nagaraju, Krishnappa

2015-07-01

Image smear, produced by the shutterless operation of frame-transfer CCD detectors, can be detrimental for many imaging applications. Existing algorithms used to numerically remove smear do not contemplate cases where intensity levels change considerably between consecutive frame exposures. In this report, we reformulate the smearing model to include specific variations of the sensor illumination. The corresponding desmearing expression and its noise properties are also presented and demonstrated in the context of fast imaging polarimetry.

Interactive definition of transfer functions in volume rendering based on image markers

International Nuclear Information System (INIS)

Teistler, Michael; Nowinski, Wieslaw L.; Breiman, Richard S.; Liong, Sauw Ming; Ho, Liang Yoong; Shahab, Atif

2007-01-01

Objectives A user interface for transfer function (TF) definition in volume rendering (VR) was developed that allows the user to intuitively assign color and opacity to the original image intensities. This software may surpass solutions currently deployed in clinical practice by simplifying the use of TFs beyond predefined settings that are not always applicable. Materials and methods The TF definition is usually a cumbersome task that requires the user to manipulate graphical representations of the TF (e.g. trapezoids). A new method that allows the user to place markers at points of interest directly on CT and MRI images or orthogonal reformations was developed based on two-dimensional region growing and a few user-definable marker-related parameters. For each user defined image marker, a segment of the transfer function is computed. The resulting TF can also be applied to the slice image views. Results were judged subjectively. Results Each individualized TF can be defined interactively in a few simple steps. For every user interaction, immediate visual feedback is given. Clinicians who tested the application appreciated being able to directly work on familiar slice images to generate the desired 3D views. Conclusion Interactive TF definition can increase the actual utility of VR, help to understand the role of the TF with its variations, and increase the acceptance of VR as a clinical tool. (orig.)

Amide proton transfer imaging in clinics: Basic concepts and current and future use in brain tumors and stoke

Energy Technology Data Exchange (ETDEWEB)

Park, Ji Eun [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of); Jahng, Geon Ho [Dept. of Radiology, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Jeong, Ha Kyu [Philips Korea, Seoul (Korea, Republic of)

2016-12-15

Amide proton transfer (APT) imaging is gaining attention as a relatively new in vivo molecular imaging technique that has higher sensitivity and spatial resolution than magnetic resonance spectroscopy imaging. APT imaging is a subset of the chemical exchange saturation transfer mechanism, which can offer unique image contrast by selectively saturating protons in target molecules that get exchanged with protons in bulk water. In this review, we describe the basic concepts of APT imaging, particularly with regard to the benefit in clinics from the current literature. Clinical applications of APT imaging are described from two perspectives: in the diagnosis and monitoring of the treatment response in brain glioma by reflecting endogenous mobile proteins and peptides, and in the potential for stroke imaging with respect to tissue acidity.

Imaging and Manipulating Energy Transfer Among Quantum Dots at Individual Dot Resolution.

Science.gov (United States)

Nguyen, Duc; Nguyen, Huy A; Lyding, Joseph W; Gruebele, Martin

2017-06-27

Many processes of interest in quantum dots involve charge or energy transfer from one dot to another. Energy transfer in films of quantum dots as well as between linked quantum dots has been demonstrated by luminescence shift, and the ultrafast time-dependence of energy transfer processes has been resolved. Bandgap variation among dots (energy disorder) and dot separation are known to play an important role in how energy diffuses. Thus, it would be very useful if energy transfer could be visualized directly on a dot-by-dot basis among small clusters or within films of quantum dots. To that effect, we report single molecule optical absorption detected by scanning tunneling microscopy (SMA-STM) to image energy pooling from donor into acceptor dots on a dot-by-dot basis. We show that we can manipulate groups of quantum dots by pruning away the dominant acceptor dot, and switching the energy transfer path to a different acceptor dot. Our experimental data agrees well with a simple Monte Carlo lattice model of energy transfer, similar to models in the literature, in which excitation energy is transferred preferentially from dots with a larger bandgap to dots with a smaller bandgap.

Use of a laser-induced fluorescence thermal imaging system for film cooling heat transfer measurement

Energy Technology Data Exchange (ETDEWEB)

Chyu, M.K. [Carnegie Mellon Univ., Pittsburgh, PA (United States)

1995-10-01

This paper describes a novel approach based on fluorescence imaging of thermographic phosphor that enables the simultaneous determination of both local film effectiveness and local heat transfer on a film-cooled surface. The film cooling model demonstrated consists of a single row of three discrete holes on a flat plate. The transient temperature measurement relies on the temperature-sensitive fluorescent properties of europium-doped lanthanum oxysulfide (La{sub 2}O{sub 2}S:EU{sup 3+}) thermographic phosphor. A series of full-field surface temperatures, mainstream temperatures, and coolant film temperatures were acquired during the heating of a test surface. These temperatures are used to calculate the heat transfer coefficients and the film effectiveness simultaneously. Because of the superior spatial resolution capability for the heat transfer data reduced from these temperature frames, the laser-induced fluorescence (LIF) imaging system, the present study observes the detailed heat transfer characteristics over a film-protected surface. The trend of the results agrees with those obtained using other conventional thermal methods, as well as the liquid crystal imaging technique. One major advantage of this technique is the capability to record a large number of temperature frames over a given testing period. This offers multiple-sample consistency.

Chemical exchange rotation transfer imaging of intermediate-exchanging amines at 2 ppm.

Science.gov (United States)

Zu, Zhongliang; Louie, Elizabeth A; Lin, Eugene C; Jiang, Xiaoyu; Does, Mark D; Gore, John C; Gochberg, Daniel F

2017-10-01

Chemical exchange saturation transfer (CEST) imaging of amine protons exchanging at intermediate rates and whose chemical shift is around 2 ppm may provide a means of mapping creatine. However, the quantification of this effect may be compromised by the influence of overlapping CEST signals from fast-exchanging amines and hydroxyls. We aimed to investigate the exchange rate filtering effect of a variation of CEST, named chemical exchange rotation transfer (CERT), as a means of isolating creatine contributions at around 2 ppm from other overlapping signals. Simulations were performed to study the filtering effects of CERT for the selection of transfer effects from protons of specific exchange rates. Control samples containing the main metabolites in brain, bovine serum albumin (BSA) and egg white albumen (EWA) at their physiological concentrations and pH were used to study the ability of CERT to isolate molecules with amines at 2 ppm that exchange at intermediate rates, and corresponding methods were used for in vivo rat brain imaging. Simulations showed that exchange rate filtering can be combined with conventional filtering based on chemical shift. Studies on samples showed that signal contributions from creatine can be separated from those of other metabolites using this combined filter, but contributions from protein amines may still be significant. This exchange filtering can also be used for in vivo imaging. CERT provides more specific quantification of amines at 2 ppm that exchange at intermediate rates compared with conventional CEST imaging. Copyright © 2017 John Wiley & Sons, Ltd.

Magnetization transfer contrast on gradient echo MR imaging of the temporomandibular joint

International Nuclear Information System (INIS)

Niitsu, M.; Hirohata, H.; Yoshioka, H.; Anno, I.; Campeau, N.G.; Itai, Y.

1995-01-01

Thirty-nine temporomandibular joints (TMJ) from 20 patients with suspected internal derangements were imaged by a 1.5 T MR imager. The on-resonance binomial magnetization transfer contrast (MTC) pulse was applied to gradient echo images with a dual receiver coil (9 s/section). With the use of an opening device, a series of sequential images were obtained at increments of mouth opening and closing. The tissue signal intensities with (Ms) and without (Mo) MTC were measured and subjective image analysis was performed. Compared with the standard images, MTC technique provided selective signal suppression of disks. The average of Ms/Mo ratio of the disks (0.56) was lower than that of the retrodiskal pad (0.79) and of the effusion (0.89). With MTC technique, fluid conspicuity was superior to standard image. However, no significant superiority was found in disk definition subjectively. (orig.)

Magnetic resonance imaging of flow and mass transfer in electrohydrodynamic liquid bridges

NARCIS (Netherlands)

Wexler, Adam D.; Drusová, Sandra; Fuchs, Elmar C.; Woisetschläger, Jakob; Reiter, Gert; Fuchsjäger, Michael; Reiter, Ursula

2017-01-01

Abstract: Here, we report on the feasibility and use of magnetic resonance imaging-based methods to the study of electrohydrodynamic (EHD) liquid bridges. High-speed tomographic recordings through the longitudinal axis of water bridges were used to characterize the mass transfer dynamics, mixing,

Characterization of orthogonal transfer array CCDs for the WIYN one degree imager

Science.gov (United States)

Lesser, Michael; Ouellette, David; Boroson, Todd; Harbeck, Daniel; Martin, Pierre; Jacoby, George; Cavin, John; Sawyer, David; Boggs, Kasey; Bredthauer, Richard

2012-03-01

The WIYN One Degree Imager (ODI) will provide a one degree field of view for the WIYN 3.5 m telescope located on Kitt Peak near Tucson, Arizona. Its focal plane consists of an 8x8 grid of Orthogonal Transfer Array (OTA) CCD detectors. These detectors are the STA2200 OTA CCDs designed and fabricated by Semiconductor Technology Associates, Inc. and backside processed at the University of Arizona Imaging Technology Laboratory. Several lot runs of the STA2200 detectors have been fabricated. We have backside processed devices from these different lots and provide detector performance characterization, including noise, CTE, cosmetics, quantum efficiency, and some orthogonal transfer characteristics. We discuss the performance differences for the devices with different silicon thickness and resistivity. A fully buttable custom detector package has been developed for this project which allows hybridization of the silicon detectors directly onto an aluminum nitride substrate with an embedded pin grid array. This package is mounted on a silicon-aluminum alloy which provides a flat imaging surface of less than 20 microns peakvalley at the -100 C operating temperature. Characterization of the package performance, including low temperature profilometry, is described in this paper.

Transferring Biomarker into Molecular Probe: Melanin Nanoparticle as a Naturally Active Platform for Multimodality Imaging

OpenAIRE

Fan, Quli; Cheng, Kai; Hu, Xiang; Ma, Xiaowei; Zhang, Ruiping; Yang, Min; Lu, Xiaomei; Xing, Lei; Huang, Wei; Gambhir, Sanjiv Sam; Cheng, Zhen

2014-01-01

Developing multifunctional and easily prepared nanoplatforms with integrated different modalities is highly challenging for molecular imaging. Here, we report the successful transfer of an important molecular target, melanin, into a novel multimodality imaging nanoplatform. Melanin is abundantly expressed in melanotic melanomas and thus has been actively studied as a target for melanoma imaging. In our work, the multifunctional biopolymer nanoplatform based on ultrasmall (

Experimental measurement of the interfacial heat transfer coefficients of subcooled flow boiling using micro-thermocouple and double directional images

International Nuclear Information System (INIS)

Seong-Jin Kim; Goon-Cherl Park

2005-01-01

Full text of publication follows: Models or correlations for phase interface are needed to analyze the multi-phase flow. Interfacial heat transfer coefficients are important to constitute energy equation of multi-phase flow, specially. In subcooled boiling flow, bubble condensation at the bubble-liquid interface is a major mechanism of heat transfer within bulk subcooled liquid. Bubble collapse rates and temperatures of each phase are needed to determine the interfacial heat transfer coefficient for bubble condensation. Bubble collapse rates were calculated through image processing in single direction, generally. And in case of liquid bulk temperature, which has been obtained by general temperature sensor such as thermocouple, was used. However, multi-directional images are needed to analyze images due to limitations of single directional image processing. Also, temperature sensor, which has a fast response time, must be used to obtain more accurate interfacial heat transfer coefficient. Low pressure subcooled water flow experiments using micro-thermocouple and double directional image processing with mirrors were conducted to investigate bubble condensation phenomena and to modify interfacial heat transfer correlation. Experiments were performed in a vertical subcooled boiling flow of a rectangular channel. Bubble condensing traces with respect to time were recorded by high speed camera in double direction and bubble collapse rates were calculated by processing recorded digital images. Temperatures were measured by micro-thermocouple, which is a K-type with a 12.7 μm diameter. The liquid temperature was estimated by the developed algorithm to discriminate phases and find each phase temperature in the measured temperature including both liquid and bubble temperature. The interfacial heat transfer coefficient for bubble condensation was calculated from the bubble collapse rates and the estimated liquid temperature, and its correlation was modified. The modified

Magneto-Plasmonics and Resonant Interaction of Light with Dynamic Magnetisation in Metallic and All-Magneto-Dielectric Nanostructures.

Science.gov (United States)

Maksymov, Ivan S

2015-04-09

A significant interest in combining plasmonics and magnetism at the nanoscale gains momentum in both photonics and magnetism sectors that are concerned with the resonant enhancement of light-magnetic-matter interaction in nanostructures. These efforts result in a considerable amount of literature, which is difficult to collect and digest in limited time. Furthermore, there is insufficient exchange of results between the two research sectors. Consequently, the goal of this review paper is to bridge this gap by presenting an overview of recent progress in the field of magneto-plasmonics from two different points of view: magneto-plasmonics, and magnonics and magnetisation dynamics. It is expected that this presentation style will make this review paper of particular interest to both general physical audience and specialists conducting research on photonics, plasmonics, Brillouin light scattering spectroscopy of magnetic nanostructures and magneto-optical Kerr effect magnetometry, as well as ultrafast all-optical and THz-wave excitation of spin waves. Moreover, readers interested in a new, rapidly emerging field of all-dielectric nanophotonics will find a section about all-magneto-dielectric nanostructures.

Magneto-Plasmonics and Resonant Interaction of Light with Dynamic Magnetisation in Metallic and All-Magneto-Dielectric Nanostructures

Directory of Open Access Journals (Sweden)

Ivan S. Maksymov

2015-04-01

Full Text Available A significant interest in combining plasmonics and magnetism at the nanoscale gains momentum in both photonics and magnetism sectors that are concerned with the resonant enhancement of light-magnetic-matter interaction in nanostructures. These efforts result in a considerable amount of literature, which is difficult to collect and digest in limited time. Furthermore, there is insufficient exchange of results between the two research sectors. Consequently, the goal of this review paper is to bridge this gap by presenting an overview of recent progress in the field of magneto-plasmonics from two different points of view: magneto-plasmonics, and magnonics and magnetisation dynamics. It is expected that this presentation style will make this review paper of particular interest to both general physical audience and specialists conducting research on photonics, plasmonics, Brillouin light scattering spectroscopy of magnetic nanostructures and magneto-optical Kerr effect magnetometry, as well as ultrafast all-optical and THz-wave excitation of spin waves. Moreover, readers interested in a new, rapidly emerging field of all-dielectric nanophotonics will find a section about all-magneto-dielectric nanostructures.

Solid-phase immunoradiometric assay for serum amyloid A protein using magnetisable cellulose particles

International Nuclear Information System (INIS)

De Beer, F.C.; Dyck, R.F.; Pepys, M.B.

1982-01-01

An immunoradiometric assay for human serum amyloid A protein (SAA) was developed using magnetisable cellulose particles as the solid phase. Rabbit antiserum to SAA was raised by immunization with SAA isolated from acute-phase serum by gel filtration in formic acid. The antiserum was rendered monospecific for SAA by solid-phase immunoabsorption with normal human serum, which contains only traces of SAA, and some was coupled covalently to the cellulose particles. Immunopurified anti-SAA antibodies were isolated from the monospecific anti-SAA serum by binding to, and elution from insolubilized acute-phase serum and were radiolabelled with 125 I. The assay was calibrated with an acute phase serum which contained 6000 times more SAA than normal sera with the lowest detectable level of SAA, and an arbitrary value of 6000 U/l was assigned to this standard. Sera were tested in the native, undenatured state and there was no increase in SAA immunoreactivity following alkali treatment or heating. The assay range was from 1-2000 U/l so that all SAA levels above 6 U/l could be measured on a single (1:6) dilution of serum. The intra- and interassay coefficients of variation were 11.7 and 15.0% respectively. Among 100 healthy normal subjects (50 male, 50 female) the median SAA level was 9 U/l, range <1-100, with 93% below 20 U/l and only 2% below the lower limit of sensitivity of the assay (1 U/l). (Auth.)

Characterization of adaptive statistical iterative reconstruction (ASIR) in low contrast helical abdominal imaging via a transfer function based method

Science.gov (United States)

Zhang, Da; Li, Xinhua; Liu, Bob

2012-03-01

Since the introduction of ASiR, its potential in noise reduction has been reported in various clinical applications. However, the influence of different scan and reconstruction parameters on the trade off between ASiR's blurring effect and noise reduction in low contrast imaging has not been fully studied. Simple measurements on low contrast images, such as CNR or phantom scores could not explore the nuance nature of this problem. We tackled this topic using a method which compares the performance of ASiR in low contrast helical imaging based on an assumed filter layer on top of the FBP reconstruction. Transfer functions of this filter layer were obtained from the noise power spectra (NPS) of corresponding FBP and ASiR images that share the same scan and reconstruction parameters. 2D transfer functions were calculated as sqrt[NPSASiR(u, v)/NPSFBP(u, v)]. Synthesized ACR phantom images were generated by filtering the FBP images with the transfer functions of specific (FBP, ASiR) pairs, and were compared with the ASiR images. It is shown that the transfer functions could predict the deterministic blurring effect of ASiR on low contrast objects, as well as the degree of noise reductions. Using this method, the influence of dose, scan field of view (SFOV), display field of view (DFOV), ASiR level, and Recon Mode on the behavior of ASiR in low contrast imaging was studied. It was found that ASiR level, dose level, and DFOV play more important roles in determining the behavior of ASiR than the other two parameters.

Chemical exchange saturation transfer MR imaging of Parkinson's disease at 3 Tesla

Energy Technology Data Exchange (ETDEWEB)

Li, Chunmei; Peng, Shuai; Wang, Rui; Chen, Min [Beijing Hospital, Department of Radiology, Beijing (China); Chen, Haibo; Su, Wen [Beijing Hospital, Department of Neurology, Beijing (China); Zhao, Xuna [Peking University, Center for MRI Research and Beijing City Key Lab for Medical Physics and Engineering, Beijing (China); Zhou, Jinyuan [Johns Hopkins University, Department of Radiology, Baltimore, MD (United States)

2014-10-15

To demonstrate the feasibility of using chemical exchange saturation transfer (CEST) imaging to detect Parkinson's disease (PD) in patients at 3 Tesla. Twenty-seven PD patients (17 men and 10 women; age range, 54-77 years) and 22 age-matched normal controls (13 men and 9 women; age range, 55-73 years) were examined on a 3-Tesla MRI system. Magnetization transfer spectra with 31 different frequency offsets (-6 to 6 ppm) were acquired at two transverse slices of the head, including the basal ganglia and midbrain. One-way analysis of variance tests was used to compare the differences in CEST imaging signals between PD patients and normal controls. Total CEST signal between the offsets of 0 and 4 ppm in the substantia nigra was significantly lower in PD patients than in normal controls (P = 0.006), which could be associated with the loss of dopaminergic neurons. Protein-based CEST imaging signals at the offset of 3.5 ppm in the globus pallidus, putamen and caudate were significantly increased in PD patients, compared to normal controls (P < 0.001, P = 0.003, P < 0.001, respectively). CEST imaging signals could potentially serve as imaging biomarkers to aid in the non-invasive molecular diagnosis of PD. (orig.)

A novel end-to-end classifier using domain transferred deep convolutional neural networks for biomedical images.

Science.gov (United States)

Pang, Shuchao; Yu, Zhezhou; Orgun, Mehmet A

2017-03-01

Highly accurate classification of biomedical images is an essential task in the clinical diagnosis of numerous medical diseases identified from those images. Traditional image classification methods combined with hand-crafted image feature descriptors and various classifiers are not able to effectively improve the accuracy rate and meet the high requirements of classification of biomedical images. The same also holds true for artificial neural network models directly trained with limited biomedical images used as training data or directly used as a black box to extract the deep features based on another distant dataset. In this study, we propose a highly reliable and accurate end-to-end classifier for all kinds of biomedical images via deep learning and transfer learning. We first apply domain transferred deep convolutional neural network for building a deep model; and then develop an overall deep learning architecture based on the raw pixels of original biomedical images using supervised training. In our model, we do not need the manual design of the feature space, seek an effective feature vector classifier or segment specific detection object and image patches, which are the main technological difficulties in the adoption of traditional image classification methods. Moreover, we do not need to be concerned with whether there are large training sets of annotated biomedical images, affordable parallel computing resources featuring GPUs or long times to wait for training a perfect deep model, which are the main problems to train deep neural networks for biomedical image classification as observed in recent works. With the utilization of a simple data augmentation method and fast convergence speed, our algorithm can achieve the best accuracy rate and outstanding classification ability for biomedical images. We have evaluated our classifier on several well-known public biomedical datasets and compared it with several state-of-the-art approaches. We propose a robust

Theoretical modelling of physiologically stretched vessel in magnetisable stent assisted magnetic drug targeting application

International Nuclear Information System (INIS)

Mardinoglu, Adil; Cregg, P.J.; Murphy, Kieran; Curtin, Maurice; Prina-Mello, Adriele

2011-01-01

The magnetisable stent assisted magnetic targeted drug delivery system in a physiologically stretched vessel is considered theoretically. The changes in the mechanical behaviour of the vessel are analysed under the influence of mechanical forces generated by blood pressure. In this 2D mathematical model a ferromagnetic, coiled wire stent is implanted to aid collection of magnetic drug carrier particles in an elastic tube, which has similar mechanical properties to the blood vessel. A cyclic mechanical force is applied to the elastic tube to mimic the mechanical stress and strain of both the stent and vessel while in the body due to pulsatile blood circulation. The magnetic dipole-dipole and hydrodynamic interactions for multiple particles are included and agglomeration of particles is also modelled. The resulting collection efficiency of the mathematical model shows that the system performance can decrease by as much as 10% due to the effects of the pulsatile blood circulation. - Research highlights: →Theoretical modelling of magnetic drug targeting on a physiologically stretched stent-vessel system. →Cyclic mechanical force applied to mimic the mechanical stress and strain of both stent and vessel. →The magnetic dipole-dipole and hydrodynamic interactions for multiple particles is modelled. →Collection efficiency of the mathematical model is calculated for different physiological blood flow and magnetic field strength.

[Chemical Exchange Saturation Transfer Imaging of Creatine Metabolites: a 3.0 T MRI Pilot].

Science.gov (United States)

Guo, Ying-kun; Li, Zhen-lin; Rong, Yu; Xia, Chun-chao; Zhang, Li-zhi; Peng, Wan-ling; Liu, Xi; Xu, Hua-yan; Zhang, Ti-jiang; Zuo, Pan-li; Schmitt, Benjamin

2016-03-01

To determine the feasibility of using chemical exchange saturation transfer (CEST) imaging to measure creatine (Cr) metabolites with 3.0 T MR. Phantoms containing different concentrations of Cr under various pH conditions were studied with CEST sequence on 3.0 T MR imaging. CEST effect and Z spectra were analyzed. Cr exhibited significant CEST effect (± 1.8 ppm, F = 99.08, P 3.0 T MR imaging, and positive correlation was found between the signal intensity and concentration of Cr (r = 0.963, P 3.0 T MR imaging. Creatine concentrations and pH influence CEST effect.

Image Processing for Bioluminescence Resonance Energy Transfer Measurement—BRET-Analyzer

Directory of Open Access Journals (Sweden)

Yan Chastagnier

2018-01-01

Full Text Available A growing number of tools now allow live recordings of various signaling pathways and protein-protein interaction dynamics in time and space by ratiometric measurements, such as Bioluminescence Resonance Energy Transfer (BRET Imaging. Accurate and reproducible analysis of ratiometric measurements has thus become mandatory to interpret quantitative imaging. In order to fulfill this necessity, we have developed an open source toolset for Fiji—BRET-Analyzer—allowing a systematic analysis, from image processing to ratio quantification. We share this open source solution and a step-by-step tutorial at https://github.com/ychastagnier/BRET-Analyzer. This toolset proposes (1 image background subtraction, (2 image alignment over time, (3 a composite thresholding method of the image used as the denominator of the ratio to refine the precise limits of the sample, (4 pixel by pixel division of the images and efficient distribution of the ratio intensity on a pseudocolor scale, and (5 quantification of the ratio mean intensity and standard variation among pixels in chosen areas. In addition to systematize the analysis process, we show that the BRET-Analyzer allows proper reconstitution and quantification of the ratiometric image in time and space, even from heterogeneous subcellular volumes. Indeed, analyzing twice the same images, we demonstrate that compared to standard analysis BRET-Analyzer precisely define the luminescent specimen limits, enlightening proficient strengths from small and big ensembles over time. For example, we followed and quantified, in live, scaffold proteins interaction dynamics in neuronal sub-cellular compartments including dendritic spines, for half an hour. In conclusion, BRET-Analyzer provides a complete, versatile and efficient toolset for automated reproducible and meaningful image ratio analysis.

Magnetization transfer on T2-weighted image : magnetization Transfer ratios in normal brain and cerebral lesions

Energy Technology Data Exchange (ETDEWEB)

Lim, Myung Kwan; Roh, Hong Gee; Suh, Chang Hae; Cho, Young Kook; Kim, Hyung Jin; Kim, Jin Hee; Kim, Sung Tae; Choi, Sung Kyu [Inha Univ. College of Medicine, Incheon (Korea, Republic of)

1998-07-01

To evaluate the magnetization transfer ratio(MTR) of various normal structures and pathologic lesions, as seen on magnetization transfer T2-weighted images (MT+T2WI). Materials and Methods : In ten normal volunteers, T2-weighted images without MT (MT-T2WI) and with MT(MT+T2WI) were obtained. Off-set pulses used in MT+T2WI were 400, 600, 1000, 1500, and 2000Hz. In 60 clinical cases infarction(n=10), brain tumors(n=5), traumatic hematomas(n=5), other hematomas(n=3) vascular malformation(n=2) white matter disease(n=2) normal(n=31) and others(n=2), both MT-T2WI and MT+T2WI images were obtained using an off-set pulse of 600 Hz. In all volunteers and patients, MTR in various normal brain parenchyma and abnormal areas was measured. Results : The MTRs of white and gray matter were 48% and 45% respectively at 400 Hz, 26% and 22% at 600Hz, 12% and 11% of 1000Hz, 10% and 9% 1500HZ, and 9% and 8% at 2000Hz of RF. The MTR of CSF was 43% at 400 Hz of off-resonance RF, while the contrast resolution of T2WI was poor. An off-resonance of 600Hz appeared to be the optimal frequency. In diseased areas,MTRs varied but were usually similar to or lower than those of brain parenchyma. Conclusion : The optimal off-resonance RF on MT+T2WI appears to be 600 Hz for relatively high MTR of brain parenchyma and low MTR of CSF,in which MTRs of white and gray matter were 26% and 22%, respectively, of 600Hz off-set pulse. The MTRs of cerebral lesions varied and further studies of various cerebral lesions are needed.

Thermal activation in statistical clusters of magnetic nanoparticles

International Nuclear Information System (INIS)

Hovorka, O

2017-01-01

This article presents a kinetic Monte-Carlo study of thermally activated magnetisation dynamics in clusters of statistically distributed magnetic nanoparticles. The structure of clusters is assumed to be of fractal nature, consistently with recent observations of magnetic particle aggregation in cellular environments. The computed magnetisation relaxation decay and frequency-dependent hysteresis loops are seen to significantly depend on the fractal dimension of aggregates, leading to accelerated magnetisation relaxation and reduction in the size of hysteresis loops as the fractal dimension increases from one-dimensional-like to three-dimensional-like clusters. Discussed are implications for applications in nanomedicine, such as magnetic hyperthermia or magnetic particle imaging. (paper)

Spherical gradient-index lenses as perfect imaging and maximum power transfer devices.

Science.gov (United States)

Gordon, J M

2000-08-01

Gradient-index lenses can be viewed from the perspectives of both imaging and nonimaging optics, that is, in terms of both image fidelity and achievable flux concentration. The simple class of gradient-index lenses with spherical symmetry, often referred to as modified Luneburg lenses, is revisited. An alternative derivation for established solutions is offered; the method of Fermat's strings and the principle of skewness conservation are invoked. Then these nominally perfect imaging devices are examined from the additional vantage point of power transfer, and the degree to which they realize the thermodynamic limit to flux concentration is determined. Finally, the spherical gradient-index lens of the fish eye is considered as a modified Luneburg lens optimized subject to material constraints.

Image Signal Transfer Method in Artificial Retina using Laser

Energy Technology Data Exchange (ETDEWEB)

Yoon, I.Y.; Lee, B.H.; Kim, S.J. [Seoul National University, Seoul (Korea)

2002-05-01

Recently, the research on artificial retina for the blind is active. In this paper a new optical link method for the retinal prosthesis is proposed. Laser diode system was chosen to transfer image into the eye in this project and the new optical system was designed and evaluated. The use of laser diode array in artificial retina system makes system simple for lack of signal processing part inside of the eyeball. Designed optical system is enough to focus laser diode array on photodiode array in 20X20 application. (author). 11 refs., 7 figs., 2 tabs.

Imaging of endogenous exchangeable proton signals in the human brain using frequency labeled exchange transfer imaging.

Science.gov (United States)

Yadav, Nirbhay N; Jones, Craig K; Hua, Jun; Xu, Jiadi; van Zijl, Peter C M

2013-04-01

To image endogenous exchangeable proton signals in the human brain using a recently reported method called frequency labeled exchange transfer (FLEX) MRI. As opposed to labeling exchangeable protons using saturation (i.e., chemical exchange saturation transfer, or CEST), FLEX labels exchangeable protons with their chemical shift evolution. The use of short high-power frequency pulses allows more efficient labeling of rapidly exchanging protons, while time domain acquisition allows removal of contamination from semi-solid magnetization transfer effects. FLEX-based exchangeable proton signals were detected in human brain over the 1-5 ppm frequency range from water. Conventional magnetization transfer contrast and the bulk water signal did not interfere in the FLEX spectrum. The information content of these signals differed from in vivo CEST data in that the average exchange rate of these signals was 350-400 s(-1) , much faster than the amide signal usually detected using direct saturation (∼30 s(-1) ). Similarly, fast exchanging protons could be detected in egg white in the same frequency range where amide and amine protons of mobile proteins and peptides are known to resonate. FLEX MRI in the human brain preferentially detects more rapidly exchanging amide/amine protons compared to traditional CEST experiments, thereby changing the information content of the exchangeable proton spectrum. This has the potential to open up different types of endogenous applications as well as more easy detection of rapidly exchanging protons in diaCEST agents or fast exchanging units such as water molecules in paracest agents without interference of conventional magnetization transfer contrast. Copyright © 2013 Wiley Periodicals, Inc.

Magnetization transfer contrast MR imaging of the knee at 0.3 T

International Nuclear Information System (INIS)

Yoshioka, Hiroshi; Onaya, Hiroaki; Niitsu, Mamoru; Anno, Izumi; Itai, Yuji; Nishimura, Hiroshi; Kajiyama, Koji; Masuda, Tomonori; Nakajima, Kotaro.

1994-01-01

It has been reported that magnetization transfer contrast (MTC) images were effective in evaluating the articular cartilage. However, only one in vivo study of the articular cartilage in the knee has been demonstrated at 1.5T. The purpose of this study was to evaluate the optimal off-resonance MTC pulse at 0.3T MR imager and assess its clinical usefulness. Five normal volunteers and eleven patients with suspected knee injuries were investigated using off-resonance sinc, gaussian, constant shaped irradiation pulses. All MTC images revealed higher contrast and contrast-to-noise (C/N) ratio between articular cartilage and external reference (saline) in the normal volunteers' knee than conventional gradient recalled echo images. MTC images with the gaussian or sinc shaped pulse were judged superior to those with constant wave pulse because the former images showed a fewer artifact with lower specific absorption rate than the latter images. The sinc MTC images were performed with the lowest SAR. The gaussian MTC images revealed better contrast and C/N between articular cartilage and joint fluid than the sinc MTC images in patients. 3D MTC images using Guassian pulse were also performed within a clinically tolerable imaging time (13 min 39 sec). Thus, MTC images in the knee at 0.3T using off-resonance pulse may be effective to assess knee injury due to better contrast between articular cartilage and joint fluid. (author)

Plane wave analysis of coherent holographic image reconstruction by phase transfer (CHIRPT).

Science.gov (United States)

Field, Jeffrey J; Winters, David G; Bartels, Randy A

2015-11-01

Fluorescent imaging plays a critical role in a myriad of scientific endeavors, particularly in the biological sciences. Three-dimensional imaging of fluorescent intensity often requires serial data acquisition, that is, voxel-by-voxel collection of fluorescent light emitted throughout the specimen with a nonimaging single-element detector. While nonimaging fluorescence detection offers some measure of scattering robustness, the rate at which dynamic specimens can be imaged is severely limited. Other fluorescent imaging techniques utilize imaging detection to enhance collection rates. A notable example is light-sheet fluorescence microscopy, also known as selective-plane illumination microscopy, which illuminates a large region within the specimen and collects emitted fluorescent light at an angle either perpendicular or oblique to the illumination light sheet. Unfortunately, scattering of the emitted fluorescent light can cause blurring of the collected images in highly turbid biological media. We recently introduced an imaging technique called coherent holographic image reconstruction by phase transfer (CHIRPT) that combines light-sheet-like illumination with nonimaging fluorescent light detection. By combining the speed of light-sheet illumination with the scattering robustness of nonimaging detection, CHIRPT is poised to have a dramatic impact on biological imaging, particularly for in vivo preparations. Here we present the mathematical formalism for CHIRPT imaging under spatially coherent illumination and present experimental data that verifies the theoretical model.

Transfer Learning with Convolutional Neural Networks for Classification of Abdominal Ultrasound Images.

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Cheng, Phillip M; Malhi, Harshawn S

2017-04-01

The purpose of this study is to evaluate transfer learning with deep convolutional neural networks for the classification of abdominal ultrasound images. Grayscale images from 185 consecutive clinical abdominal ultrasound studies were categorized into 11 categories based on the text annotation specified by the technologist for the image. Cropped images were rescaled to 256 × 256 resolution and randomized, with 4094 images from 136 studies constituting the training set, and 1423 images from 49 studies constituting the test set. The fully connected layers of two convolutional neural networks based on CaffeNet and VGGNet, previously trained on the 2012 Large Scale Visual Recognition Challenge data set, were retrained on the training set. Weights in the convolutional layers of each network were frozen to serve as fixed feature extractors. Accuracy on the test set was evaluated for each network. A radiologist experienced in abdominal ultrasound also independently classified the images in the test set into the same 11 categories. The CaffeNet network classified 77.3% of the test set images accurately (1100/1423 images), with a top-2 accuracy of 90.4% (1287/1423 images). The larger VGGNet network classified 77.9% of the test set accurately (1109/1423 images), with a top-2 accuracy of VGGNet was 89.7% (1276/1423 images). The radiologist classified 71.7% of the test set images correctly (1020/1423 images). The differences in classification accuracies between both neural networks and the radiologist were statistically significant (p convolutional neural networks may be used to construct effective classifiers for abdominal ultrasound images.

Ultra-portable field transfer radiometer for vicarious calibration of earth imaging sensors

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Thome, Kurtis; Wenny, Brian; Anderson, Nikolaus; McCorkel, Joel; Czapla-Myers, Jeffrey; Biggar, Stuart

2018-06-01

A small portable transfer radiometer has been developed as part of an effort to ensure the quality of upwelling radiance from test sites used for vicarious calibration in the solar reflective. The test sites are used to predict top-of-atmosphere reflectance relying on ground-based measurements of the atmosphere and surface. The portable transfer radiometer is designed for one-person operation for on-site field calibration of instrumentation used to determine ground-leaving radiance. The current work describes the detector- and source-based radiometric calibration of the transfer radiometer highlighting the expected accuracy and SI-traceability. The results indicate differences between the detector-based and source-based results greater than the combined uncertainties of the approaches. Results from recent field deployments of the transfer radiometer using a solar radiation based calibration agree with the source-based laboratory calibration within the combined uncertainties of the methods. The detector-based results show a significant difference to the solar-based calibration. The source-based calibration is used as the basis for a radiance-based calibration of the Landsat-8 Operational Land Imager that agrees with the OLI calibration to within the uncertainties of the methods.

Brain MR post-gadolinium contrast in multiple sclerosis: the role of magnetization transfer and image subtraction in detecting more enhancing lesions

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Gavra, M.M.; Gouliamos, A.D.; Vlahos, L.J. [Department of Radiology, ' ' Aretaieion' ' Hospital,University of Athens Medical School, Athens (Greece); Voumvourakis, C.; Sfagos, C. [Department of Neurology, ' ' Eginiteion' ' Hospital, University of Athens Medical School, Athens (Greece)

2004-03-01

Our purpose was to evaluate the role of magnetization transfer and image subtraction in detecting more enhancing lesions in brain MR imaging of patients with multiple sclerosis (MS). Thirty-one MS patients underwent MR imaging of the brain with T1-weighted spin echo sequences without and with magnetization transfer (MT) using a 1.5 T imager. Both sequences were acquired before and after intravenous injection of a paramagnetic contrast agent. Subtraction images in T1-weighted sequences were obtained by subtracting the pre-contrast images from the post-contrast ones. A significant difference was found between the numbers of enhanced areas in post-gadolinium T1-weighted images without and with MT (p=0.020). The post-gadolinium T1-weighted images with MT allowed the detection of an increased (13) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. A significant difference was also found between the numbers of enhanced areas in post-gadolinium T1-weighted images without MT and subtraction images without MT (p=0.020). The subtraction images without MT allowed the detection of an increased (10) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. Magnetization transfer contrast and subtraction techniques appear to be the simplest and least time-consuming applications to improve the conspicuity and detection of contrast-enhancing lesions in patients with MS. (orig.)

Brain MR post-gadolinium contrast in multiple sclerosis: the role of magnetization transfer and image subtraction in detecting more enhancing lesions

International Nuclear Information System (INIS)

Gavra, M.M.; Gouliamos, A.D.; Vlahos, L.J.; Voumvourakis, C.; Sfagos, C.

2004-01-01

Our purpose was to evaluate the role of magnetization transfer and image subtraction in detecting more enhancing lesions in brain MR imaging of patients with multiple sclerosis (MS). Thirty-one MS patients underwent MR imaging of the brain with T1-weighted spin echo sequences without and with magnetization transfer (MT) using a 1.5 T imager. Both sequences were acquired before and after intravenous injection of a paramagnetic contrast agent. Subtraction images in T1-weighted sequences were obtained by subtracting the pre-contrast images from the post-contrast ones. A significant difference was found between the numbers of enhanced areas in post-gadolinium T1-weighted images without and with MT (p=0.020). The post-gadolinium T1-weighted images with MT allowed the detection of an increased (13) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. A significant difference was also found between the numbers of enhanced areas in post-gadolinium T1-weighted images without MT and subtraction images without MT (p=0.020). The subtraction images without MT allowed the detection of an increased (10) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. Magnetization transfer contrast and subtraction techniques appear to be the simplest and least time-consuming applications to improve the conspicuity and detection of contrast-enhancing lesions in patients with MS. (orig.)

Coded aperture imaging: the modulation transfer function for uniformly redundant arrays

International Nuclear Information System (INIS)

Fenimore, E.E.

1980-01-01

Coded aperture imaging uses many pinholes to increase the SNR for intrinsically weak sources when the radiation can be neither reflected nor refracted. Effectively, the signal is multiplexed onto an image and then decoded, often by a computer, to form a reconstructed image. We derive the modulation transfer function (MTF) of such a system employing uniformly redundant arrays (URA). We show that the MTF of a URA system is virtually the same as the MTF of an individual pinhole regardless of the shape or size of the pinhole. Thus, only the location of the pinholes is important for optimum multiplexing and decoding. The shape and size of the pinholes can then be selected based on other criteria. For example, one can generate self-supporting patterns, useful for energies typically encountered in the imaging of laser-driven compressions or in soft x-ray astronomy. Such patterns contain holes that are all the same size, easing the etching or plating fabrication efforts for the apertures. A new reconstruction method is introduced called delta decoding. It improves the resolution capabilities of a coded aperture system by mitigating a blur often introduced during the reconstruction step

Nuclear magnetic resonance apparatus

International Nuclear Information System (INIS)

Lambert, R.

1991-01-01

In order to include the effect of a magnetic object in a subject under investigation, Nuclear Magnetic Resonance (NMR) apparatus is operable at more than one radio frequency (RF) frequency. The apparatus allows normal practice as far as obtaining an NMR response or image from a given nuclear species is concerned, but, in addition, interrogates the nuclear spin system at a frequency which is different from the resonance frequency normally used for the given nuclear species, as determined from the applied magnetic field. The magnetic field close to a magnetised or magnetisable object is modified and the given nuclear species gives a response at the different frequency. Thus detection of a signal at the frequency indicates the presence of the chosen nuclei close to the magnetised or magnetisable object. Applications include validation of an object detection or automatic shape inspection system in the presence of magnetic impurities, and the detection of magnetic particles which affect measurement of liquid flow in a pipe. (author)

Highly sensitive and area-efficient CMOS image sensor using a PMOSFET-type photodetector with a built-in transfer gate

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Seo, Sang-Ho; Kim, Kyoung-Do; Kong, Jae-Sung; Shin, Jang-Kyoo; Choi, Pyung

2007-02-01

In this paper, a new CMOS image sensor is presented, which uses a PMOSFET-type photodetector with a transfer gate that has a high and variable sensitivity. The proposed CMOS image sensor has been fabricated using a 0.35 μm 2-poly 4- metal standard CMOS technology and is composed of a 256 × 256 array of 7.05 × 7.10 μm pixels. The unit pixel has a configuration of a pseudo 3-transistor active pixel sensor (APS) with the PMOSFET-type photodetector with a transfer gate, which has a function of conventional 4-transistor APS. The generated photocurrent is controlled by the transfer gate of the PMOSFET-type photodetector. The maximum responsivity of the photodetector is larger than 1.0 × 10 3 A/W without any optical lens. Fabricated 256 × 256 CMOS image sensor exhibits a good response to low-level illumination as low as 5 lux.

ADvanced IMage Algebra (ADIMA): a novel method for depicting multiple sclerosis lesion heterogeneity, as demonstrated by quantitative MRI.

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Yiannakas, Marios C; Tozer, Daniel J; Schmierer, Klaus; Chard, Declan T; Anderson, Valerie M; Altmann, Daniel R; Miller, David H; Wheeler-Kingshott, Claudia A M

2013-05-01

There are modest correlations between multiple sclerosis (MS) disability and white matter lesion (WML) volumes, as measured by T2-weighted (T2w) magnetic resonance imaging (MRI) scans (T2-WML). This may partly reflect pathological heterogeneity in WMLs, which is not apparent on T2w scans. To determine if ADvanced IMage Algebra (ADIMA), a novel MRI post-processing method, can reveal WML heterogeneity from proton-density weighted (PDw) and T2w images. We obtained conventional PDw and T2w images from 10 patients with relapsing-remitting MS (RRMS) and ADIMA images were calculated from these. We classified all WML into bright (ADIMA-b) and dark (ADIMA-d) sub-regions, which were segmented. We obtained conventional T2-WML and T1-WML volumes for comparison, as well as the following quantitative magnetic resonance parameters: magnetisation transfer ratio (MTR), T1 and T2. Also, we assessed the reproducibility of the segmentation for ADIMA-b, ADIMA-d and T2-WML. Our study's ADIMA-derived volumes correlated with conventional lesion volumes (p < 0.05). ADIMA-b exhibited higher T1 and T2, and lower MTR than the T2-WML (p < 0.001). Despite the similarity in T1 values between ADIMA-b and T1-WML, these regions were only partly overlapping with each other. ADIMA-d exhibited quantitative characteristics similar to T2-WML; however, they were only partly overlapping. Mean intra- and inter-observer coefficients of variation for ADIMA-b, ADIMA-d and T2-WML volumes were all < 6 % and < 10 %, respectively. ADIMA enabled the simple classification of WML into two groups having different quantitative magnetic resonance properties, which can be reproducibly distinguished.

Identification and prioritization of rail squat defects in the field using rail magnetisation technology

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Kaewunruen, Sakdirat

2015-04-01

Inevitably, rail squats and studs are continuing to be a serious problem for railway organisations around the world in the 21st century. They are typically classified as the growth of any cracks that have grown longitudinally through the subsurface and some of the cracks propagating to the bottom of rails transversely, and have branched from initial longitudinal cracks with a depression of rail surface. The horizontal crack, which results in a depression of rail surface, induces increased maintenance level, more frequent monitoring, compromised rail testing (as the crack shields the signal echoes), and possible broken rails. This paper presents field investigations using a magnetised-rail testing device developed by MRX Technologies to identify and prioritise the rail squats. Most of the in situ squats were found on the high rail of the transition (variable-radius curved track), which is associated with rolling contact fatigue (RCF). This investigation highlights the field performance of the MRX's surface crack detection technology in comparison with the traditional ultrasonic method and detailed walking inspection. Visually, it was found in the field that the size of the RCF squats varies from very small to moderate. The predicted crack data were obtained by scanning the magnitised rails. The comparison of the actual crack depths (ultrasonic) and the predicted crack depths (MRX device) shows: • A possible correlation for small RCF/ squat cracks. • Poor interpretation of larger defects and welds. The field assessment also suggests some practical issues required for further development, including the detection of rail spalling, deep transverse crack, welding, and so on.

Magnetisation and AC susceptibility studies of La1-xSrxFe0.8Cr0.2O3-δ (0.0

International Nuclear Information System (INIS)

Ferreira, L.P.; Cruz, M.M.; Ramos, T.; Sa, M.A.; Carvalho, M.D.; Godinho, M.

2007-01-01

Magnetisation and AC magnetic susceptibility measurements have been performed in the perovskite-type compounds La 1-x Sr x Fe 0.8 Cr 0.2 O 3-δ (x=0.2, 0.4, 0.6 and 0.8). All compounds show an overall antiferromagnetic behaviour mainly attributed to predominant Fe 3+ -O-Fe 3+ interactions. For 0.2 ord . The coexistence of AFM and FM interactions leads to reentrant magnetic behaviour for the x=0.4 compound and to spin-glass like behaviour for x=0.8. Between x=0.6 and 0.8, the similar magnetic moments found in the paramagnetic region indicate that the Fe/Cr valences do not change significantly, pointing towards an increased role for oxygen vacancy formation in the charge compensation mechanism

Short-Term Solar Irradiance Forecasts Using Sky Images and Radiative Transfer Model

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Juan Du

2018-05-01

Full Text Available In this paper, we propose a novel forecast method which addresses the difficulty in short-term solar irradiance forecasting that arises due to rapidly evolving environmental factors over short time periods. This involves the forecasting of Global Horizontal Irradiance (GHI that combines prediction sky images with a Radiative Transfer Model (RTM. The prediction images (up to 10 min ahead are produced by a non-local optical flow method, which is used to calculate the cloud motion for each pixel, with consecutive sky images at 1 min intervals. The Direct Normal Irradiance (DNI and the diffuse radiation intensity field under clear sky and overcast conditions obtained from the RTM are then mapped to the sky images. Through combining the cloud locations on the prediction image with the corresponding instance of image-based DNI and diffuse radiation intensity fields, the GHI can be quantitatively forecasted for time horizons of 1–10 min ahead. The solar forecasts are evaluated in terms of root mean square error (RMSE and mean absolute error (MAE in relation to in-situ measurements and compared to the performance of the persistence model. The results of our experiment show that GHI forecasts using the proposed method perform better than the persistence model.

Nuclear overhauser enhancement mediated chemical exchange saturation transfer imaging at 7 Tesla in glioblastoma patients.

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Daniel Paech

Full Text Available BACKGROUND AND PURPOSE: Nuclear Overhauser Enhancement (NOE mediated chemical exchange saturation transfer (CEST is a novel magnetic resonance imaging (MRI technique on the basis of saturation transfer between exchanging protons of tissue proteins and bulk water. The purpose of this study was to evaluate and compare the information provided by three dimensional NOE mediated CEST at 7 Tesla (7T and standard MRI in glioblastoma patients. PATIENTS AND METHODS: Twelve patients with newly diagnosed histologically proven glioblastoma were enrolled in this prospective ethics committee-approved study. NOE mediated CEST contrast was acquired with a modified three-dimensional gradient-echo sequence and asymmetry analysis was conducted at 3.3 ppm (B1 = 0.7 µT to calculate the magnetization transfer ratio asymmetry (MTR(asym. Contrast enhanced T1 (CE-T1 and T2-weighted images were acquired at 3T and used for data co-registration and comparison. RESULTS: Mean NOE mediated CEST signal based on MTR(asym values over all patients was significantly increased (p<0.001 in CE-T1 tumor (-1.99 ± 1.22%, tumor necrosis (-1.36 ± 1.30% and peritumoral CEST hyperintensities (PTCH within T2 edema margins (-3.56 ± 1.24% compared to contralateral normal appearing white matter (-8.38 ± 1.19%. In CE-T1 tumor (p = 0.015 and tumor necrosis (p<0.001 mean MTR(asym values were significantly higher than in PTCH. Extent of the surrounding tumor hyperintensity was smaller in eight out of 12 patients on CEST than on T2-weighted images, while four displayed at equal size. In all patients, isolated high intensity regions (0.40 ± 2.21% displayed on CEST within the CE-T1 tumor that were not discernible on CE-T1 or T2-weighted images. CONCLUSION: NOE mediated CEST Imaging at 7 T provides additional information on the structure of peritumoral hyperintensities in glioblastoma and displays isolated high intensity regions within the CE-T1 tumor that cannot be acquired on CE-T1 or T2

PET/CT (and CT) instrumentation, image reconstruction and data transfer for radiotherapy planning

International Nuclear Information System (INIS)

Sattler, Bernhard; Lee, John A.; Lonsdale, Markus; Coche, Emmanuel

2010-01-01

computed tomography (CT) are used to communicate the actual image data created by the modalities. Care must be taken for data security, especially when transferring data across the (network-) borders of different hospitals. Overall, the most important precondition for successful integration of functional imaging in RT treatment planning is the goal orientated as well as close and thorough communication between nuclear medicine and radiotherapy departments on all levels of interaction (personnel, imaging protocols, GTV delineation, and selection of the data transfer method).

The Physics of Imaging with Remote Sensors : Photon State Space & Radiative Transfer

Science.gov (United States)

Davis, Anthony B.

2012-01-01

Standard (mono-pixel/steady-source) retrieval methodology is reaching its fundamental limit with access to multi-angle/multi-spectral photo- polarimetry. Next... Two emerging new classes of retrieval algorithm worth nurturing: multi-pixel time-domain Wave-radiometry transition regimes, and more... Cross-fertilization with bio-medical imaging. Physics-based remote sensing: - What is "photon state space?" - What is "radiative transfer?" - Is "the end" in sight? Two wide-open frontiers! center dot Examples (with variations.

Recent Advances in Nanoparticle-Based Förster Resonance Energy Transfer for Biosensing, Molecular Imaging and Drug Release Profiling

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Nai-Tzu Chen

2012-12-01

Full Text Available Förster resonance energy transfer (FRET may be regarded as a “smart” technology in the design of fluorescence probes for biological sensing and imaging. Recently, a variety of nanoparticles that include quantum dots, gold nanoparticles, polymer, mesoporous silica nanoparticles and upconversion nanoparticles have been employed to modulate FRET. Researchers have developed a number of “visible” and “activatable” FRET probes sensitive to specific changes in the biological environment that are especially attractive from the biomedical point of view. This article reviews recent progress in bringing these nanoparticle-modulated energy transfer schemes to fruition for applications in biosensing, molecular imaging and drug delivery.

Cascade Convolutional Neural Network Based on Transfer-Learning for Aircraft Detection on High-Resolution Remote Sensing Images

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Bin Pan

2017-01-01

Full Text Available Aircraft detection from high-resolution remote sensing images is important for civil and military applications. Recently, detection methods based on deep learning have rapidly advanced. However, they require numerous samples to train the detection model and cannot be directly used to efficiently handle large-area remote sensing images. A weakly supervised learning method (WSLM can detect a target with few samples. However, it cannot extract an adequate number of features, and the detection accuracy requires improvement. We propose a cascade convolutional neural network (CCNN framework based on transfer-learning and geometric feature constraints (GFC for aircraft detection. It achieves high accuracy and efficient detection with relatively few samples. A high-accuracy detection model is first obtained using transfer-learning to fine-tune pretrained models with few samples. Then, a GFC region proposal filtering method improves detection efficiency. The CCNN framework completes the aircraft detection for large-area remote sensing images. The framework first-level network is an image classifier, which filters the entire image, excluding most areas with no aircraft. The second-level network is an object detector, which rapidly detects aircraft from the first-level network output. Compared with WSLM, detection accuracy increased by 3.66%, false detection decreased by 64%, and missed detection decreased by 23.1%.

Longitudinal assessment of mouse renal injury using high-resolution anatomic and magnetization transfer MR imaging.

Science.gov (United States)

Wang, Feng; Jiang, Rosie; Takahashi, Keiko; Gore, John; Harris, Raymond C; Takahashi, Takamune; Quarles, C Chad

2014-11-01

The purpose of this study is to evaluate the utility of high-resolution non-invasive endogenous high-field MRI methods for the longitudinal structural and quantitative assessments of mouse kidney disease using the model of unilateral ureter obstruction (UUO). T1-weighted, T2-weighted and magnetization transfer (MT) imaging protocols were optimized to improve the regional contrast in mouse kidney. Conventional T1 and T2 weighted images were collected in UUO mice on day 0 (~3h), day 1, day 3 and day 6 after injury, on a 7 T small animal MRI system. Cortical and medullary thickness, corticomedullary contrast and Magnetization Transfer Ratio (MTR) were assessed longitudinally. Masson trichrome staining was used to histologically assess changes in tissue microstructure. Over the course of UUO progression there were significant (prenal cortical and medullary atrophy, cortical-medullary differentiation and MTR changes provide an endogenous, non-invasive and quantitative evaluation of renal morphology and tissue composition during UUO progression. Copyright © 2014 Elsevier Inc. All rights reserved.

Imaging and modeling of collagen architecture in living tissue with polarized light transfer (Conference Presentation)

Science.gov (United States)

Ramella-Roman, Jessica C.; Stoff, Susan; Chue-Sang, Joseph; Bai, Yuqiang

2016-03-01

The extra-cellular space in connective tissue of animals and humans alike is comprised in large part of collagen. Monitoring of collagen arrangement and cross-linking has been utilized to diagnose a variety of medical conditions and guide surgical intervention. For example, collagen monitoring is useful in the assessment and treatment of cervical cancer, skin cancer, myocardial infarction, and non-arteritic anterior ischemic optic neuropathy. We have developed a suite of tools and models based on polarized light transfer for the assessment of collagen presence, cross-linking, and orientation in living tissue. Here we will present some example of such approach applied to the human cervix. We will illustrate a novel Mueller Matrix (MM) imaging system for the study of cervical tissue; furthermore we will show how our model of polarized light transfer through cervical tissue compares to the experimental findings. Finally we will show validation of the methodology through histological results and Second Harmonic imaging microscopy.

One Size Fits All: Evaluation of the Transferability of a New "Learning" Histologic Image Analysis Application.

Science.gov (United States)

Arlt, Janine; Homeyer, André; Sänger, Constanze; Dahmen, Uta; Dirsch, Olaf

2016-01-01

Quantitative analysis of histologic slides is of importance for pathology and also to address surgical questions. Recently, a novel application was developed for the automated quantification of whole-slide images. The aim of this study was to test and validate the underlying image analysis algorithm with respect to user friendliness, accuracy, and transferability to different histologic scenarios. The algorithm splits the images into tiles of a predetermined size and identifies the tissue class of each tile. In the training procedure, the user specifies example tiles of the different tissue classes. In the subsequent analysis procedure, the algorithm classifies each tile into the previously specified classes. User friendliness was evaluated by recording training time and testing reproducibility of the training procedure of users with different background. Accuracy was determined with respect to single and batch analysis. Transferability was demonstrated by analyzing tissue of different organs (rat liver, kidney, small bowel, and spleen) and with different stainings (glutamine synthetase and hematoxylin-eosin). Users of different educational background could apply the program efficiently after a short introduction. When analyzing images with similar properties, accuracy of >90% was reached in single images as well as in batch mode. We demonstrated that the novel application is user friendly and very accurate. With the "training" procedure the application can be adapted to novel image characteristics simply by giving examples of relevant tissue structures. Therefore, it is suitable for the fast and efficient analysis of high numbers of fully digitalized histologic sections, potentially allowing "high-throughput" quantitative "histomic" analysis.

Ultra-fast stem cell labelling using cationised magnetoferritin

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Correia Carreira, S.; Armstrong, J. P. K.; Seddon, A. M.; Perriman, A. W.; Hartley-Davies, R.; Schwarzacher, W.

2016-03-01

Magnetic cell labelling with superparamagnetic iron oxide nanoparticles (SPIONs) facilitates many important biotechnological applications, such as cell imaging and remote manipulation. However, to achieve adequate cellular loading of SPIONs, long incubation times (24 hours and more) or laborious surface functionalisation are often employed, which can adversely affect cell function. Here, we demonstrate that chemical cationisation of magnetoferritin produces a highly membrane-active nanoparticle that can magnetise human mesenchymal stem cells (hMSCs) using incubation times as short as one minute. Magnetisation persisted for several weeks in culture and provided significant T2* contrast enhancement during magnetic resonance imaging. Exposure to cationised magnetoferritin did not adversely affect the membrane integrity, proliferation and multi-lineage differentiation capacity of hMSCs, which provides the first detailed evidence for the biocompatibility of magnetoferritin. The combination of synthetic ease and flexibility, the rapidity of labelling and absence of cytotoxicity make this novel nanoparticle system an easily accessible and versatile platform for a range of cell-based therapies in regenerative medicine.Magnetic cell labelling with superparamagnetic iron oxide nanoparticles (SPIONs) facilitates many important biotechnological applications, such as cell imaging and remote manipulation. However, to achieve adequate cellular loading of SPIONs, long incubation times (24 hours and more) or laborious surface functionalisation are often employed, which can adversely affect cell function. Here, we demonstrate that chemical cationisation of magnetoferritin produces a highly membrane-active nanoparticle that can magnetise human mesenchymal stem cells (hMSCs) using incubation times as short as one minute. Magnetisation persisted for several weeks in culture and provided significant T2* contrast enhancement during magnetic resonance imaging. Exposure to cationised

Characterizing amide proton transfer imaging in haemorrhage brain lesions using 3T MRI

Energy Technology Data Exchange (ETDEWEB)

Jeong, Ha-Kyu [Philips Korea, Seoul (Korea, Republic of); Korea Basic Science Institute, Chungcheongbuk-do (Korea, Republic of); Han, Kyunghwa [Yonsei University College of Medicine, Department of Radiology and Research Institute of Radiological Science, Seodaemun-gu, Seoul (Korea, Republic of); Yonsei University College of Medicine, Yonsei Biomedical Research Institute, Seoul (Korea, Republic of); Zhou, Jinyuan [Johns Hopkins University School of Medicine, Division of MRI Research, Department of Radiology, Baltimore, MD (United States); Zhao, Yansong [Philips Healthcare, MR Clinical Science, Cleveland, OH (United States); Choi, Yoon Seong; Lee, Seung-Koo; Ahn, Sung Soo [Yonsei University College of Medicine, Department of Radiology and Research Institute of Radiological Science, Seodaemun-gu, Seoul (Korea, Republic of)

2017-04-15

The aim of this study was to characterize amide proton transfer (APT)-weighted signals in acute and subacute haemorrhage brain lesions of various underlying aetiologies. Twenty-three patients with symptomatic haemorrhage brain lesions including tumorous (n = 16) and non-tumorous lesions (n = 7) were evaluated. APT imaging was performed and analyzed with magnetization transfer ratio asymmetry (MTR{sub asym}). Regions of interest were defined as the enhancing portion (when present), acute or subacute haemorrhage, and normal-appearing white matter based on anatomical MRI. MTR{sub asym} values were compared among groups and components using a linear mixed model. MTR{sub asym} values were 3.68 % in acute haemorrhage, 1.6 % in subacute haemorrhage, 2.65 % in the enhancing portion, and 0.38 % in normal white matter. According to the linear mixed model, the distribution of MTR{sub asym} values among components was not significantly different between tumour and non-tumour groups. MTR{sub asym} in acute haemorrhage was significantly higher than those in the other regions regardless of underlying pathology. Acute haemorrhages showed high MTR{sub asym} regardless of the underlying pathology, whereas subacute haemorrhages showed lower MTR{sub asym} than acute haemorrhages. These results can aid in the interpretation of APT imaging in haemorrhage brain lesions. (orig.)

End-to-End Airplane Detection Using Transfer Learning in Remote Sensing Images

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Zhong Chen

2018-01-01

Full Text Available Airplane detection in remote sensing images remains a challenging problem due to the complexity of backgrounds. In recent years, with the development of deep learning, object detection has also obtained great breakthroughs. For object detection tasks in natural images, such as the PASCAL (Pattern Analysis, Statistical Modelling and Computational Learning VOC (Visual Object Classes Challenge, the major trend of current development is to use a large amount of labeled classification data to pre-train the deep neural network as a base network, and then use a small amount of annotated detection data to fine-tune the network for detection. In this paper, we use object detection technology based on deep learning for airplane detection in remote sensing images. In addition to using some characteristics of remote sensing images, some new data augmentation techniques have been proposed. We also use transfer learning and adopt a single deep convolutional neural network and limited training samples to implement end-to-end trainable airplane detection. Classification and positioning are no longer divided into multistage tasks; end-to-end detection attempts to combine them for optimization, which ensures an optimal solution for the final stage. In our experiment, we use remote sensing images of airports collected from Google Earth. The experimental results show that the proposed algorithm is highly accurate and meaningful for remote sensing object detection.

Seven-Tesla Magnetization Transfer Imaging to Detect Multiple Sclerosis White Matter Lesions.

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Chou, I-Jun; Lim, Su-Yin; Tanasescu, Radu; Al-Radaideh, Ali; Mougin, Olivier E; Tench, Christopher R; Whitehouse, William P; Gowland, Penny A; Constantinescu, Cris S

2018-03-01

Fluid-attenuated inversion recovery (FLAIR) imaging at 3 Tesla (T) field strength is the most sensitive modality for detecting white matter lesions in multiple sclerosis. While 7T FLAIR is effective in detecting cortical lesions, it has not been fully optimized for visualization of white matter lesions and thus has not been used for delineating lesions in quantitative magnetic resonance imaging (MRI) studies of the normal appearing white matter in multiple sclerosis. Therefore, we aimed to evaluate the sensitivity of 7T magnetization-transfer-weighted (MT w ) images in the detection of white matter lesions compared with 3T-FLAIR. Fifteen patients with clinically isolated syndrome, 6 with multiple sclerosis, and 10 healthy participants were scanned with 7T 3-dimensional (D) MT w and 3T-2D-FLAIR sequences on the same day. White matter lesions visible on either sequence were delineated. Of 662 lesions identified on 3T-2D-FLAIR images, 652 were detected on 7T-3D-MT w images (sensitivity, 98%; 95% confidence interval, 97% to 99%). The Spearman correlation coefficient between lesion loads estimated by the two sequences was .910. The intrarater and interrater reliability for 7T-3D-MT w images was good with an intraclass correlation coefficient (ICC) of 98.4% and 81.8%, which is similar to that for 3T-2D-FLAIR images (ICC 96.1% and 96.7%). Seven-Tesla MT w sequences detected most of the white matter lesions identified by FLAIR at 3T. This suggests that 7T-MT w imaging is a robust alternative for detecting demyelinating lesions in addition to 3T-FLAIR. Future studies need to compare the roles of optimized 7T-FLAIR and of 7T-MT w imaging. © 2017 The Authors. Journal of Neuroimaging published by Wiley Periodicals, Inc. on behalf of American Society of Neuroimaging.

The effects of image transfer strategy achieved through cobranding and brand extension

Directory of Open Access Journals (Sweden)

Rakita Branko

2010-01-01

Full Text Available This paper investigates the strategic importance of brand extension and cobranding. These two strategies we identify as the most important and the most popular brand image transfer strategies. They are widely adopted strategies for firms entering new markets, so they can take advantage of an existing brand's equity. In this article, we investigate whether cobranding with partner and brand extension has positive effects on customers' responses toward a new product. We also analyzed prerequisites for successful implementation of mentioned brand strategies. .

Time-resolved imaging of flyer dynamics for femtosecond laser-induced backward transfer of solid polymer thin films

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Feinaeugle, M., E-mail: m.feinaeugle@utwente.nl [Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Gregorčič, P. [Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, 1000, Ljubljana (Slovenia); Heath, D.J. [Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Mills, B., E-mail: bm602@orc.soton.ac.uk [Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Eason, R.W. [Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ (United Kingdom)

2017-02-28

Highlights: • Laser-induced backward transfer was investigated by time-resolved shadowgraphy. • Flyer velocity was a function of carrier, donor thickness, delay and fluence. • We investigated the fluence window for intact transfer and the role of the receiver. • Donor-crater profile variation was studied for different ejection regimes. • Conditions for intact and fragmented flyers were determined. - Abstract: We have studied the transfer regimes and dynamics of polymer flyers from laser-induced backward transfer (LIBT) via time-resolved shadowgraphy. Imaging of the flyer ejection phase of LIBT of 3.8 μm and 6.4 μm thick SU-8 polymer films on germanium and silicon carrier substrates was performed over a time delay range of 1.4–16.4 μs after arrival of the laser pulse. The experiments were carried out with 150 fs, 800 nm pulses spatially shaped using a digital micromirror device, and laser fluences of up to 3.5 J/cm{sup 2} while images were recorded via a CCD camera and a spark discharge lamp. Velocities of flyers found in the range of 6–20 m/s, and the intact and fragmented ejection regimes, were a function of donor thickness, carrier and laser fluence. The crater profile of the donor after transfer and the resulting flyer profile indicated different flyer ejection modes for Si carriers and high fluences. The results contribute to better understanding of the LIBT process, and help to determine experimental parameters for successful LIBT of intact deposits.

Pore-scale study on flow and heat transfer in 3D reconstructed porous media using micro-tomography images

International Nuclear Information System (INIS)

Liu, Zhenyu; Wu, Huiying

2016-01-01

Highlights: • The complex porous domain has been reconstructed with the micro CT scan images. • Pore-scale numerical model based on LB method has been established. • The correlations for flow and heat transfer were derived from the predictions. • The numerical approach developed in this work is suitable for complex porous media. - Abstract: This paper presents the numerical study on fluid flow and heat transfer in reconstructed porous media at the pore-scale with the double-population thermal lattice Boltzmann (LB) method. The porous geometry was reconstructed using micro-tomography images from micro-CT scanner. The thermal LB model was numerically tested before simulation and a good agreement was achieved by compared with the existing results. The detailed distributions of velocity and temperature in complex pore spaces were obtained from the pore-scale simulation. The correlations for flow and heat transfer in the specific porous media sample were derived based on the numerical results. The numerical method established in this work provides a promising approach to predict pore-scale flow and heat transfer characteristics in reconstructed porous domain with real geometrical effect, which can be extended for the continuum modeling of the transport process in porous media at macro-scale.

Quantitative magnetization transfer imaging of rodent glioma using selective inversion recovery.

Science.gov (United States)

Xu, Junzhong; Li, Ke; Zu, Zhongliang; Li, Xia; Gochberg, Daniel F; Gore, John C

2014-03-01

Magnetization transfer (MT) provides an indirect means to detect noninvasively variations in macromolecular contents in biological tissues, but, so far, there have been only a few quantitative MT (qMT) studies reported in cancer, all of which used off-resonance pulsed saturation methods. This article describes the first implementation of a different qMT approach, selective inversion recovery (SIR), for the characterization of tumor in vivo using a rodent glioma model. The SIR method is an on-resonance method capable of fitting qMT parameters and T1 relaxation time simultaneously without mapping B0 and B1 , which is very suitable for high-field qMT measurements because of the lower saturation absorption rate. The results show that the average pool size ratio (PSR, the macromolecular pool versus the free water pool) in rat 9 L glioma (5.7%) is significantly lower than that in normal rat gray matter (9.2%) and white matter (17.4%), which suggests that PSR is potentially a sensitive imaging biomarker for the assessment of brain tumor. Despite being less robust, the estimated MT exchange rates also show clear differences from normal tissues (19.7 Hz for tumors versus 14.8 and 10.2 Hz for gray and white mater, respectively). In addition, the influence of confounding effects, e.g. B1 inhomogeneity, on qMT parameter estimates is investigated with numerical simulations. These findings not only help to better understand the changes in the macromolecular contents of tumors, but are also important for the interpretation of other imaging contrasts, such as chemical exchange saturation transfer of tumors. Copyright © 2013 John Wiley & Sons, Ltd.

Chemical exchange saturation transfer (CEST) MR technique for in-vivo liver imaging at 3.0 tesla

Energy Technology Data Exchange (ETDEWEB)

Chen, Shu-Zhong; Deng, Min; Wang, Yi-Xiang J. [Chinese University of Hong Kong, Prince of Wales Hospital, Department of Imaging and Interventional Radiology, Faculty of Medicine (China); Yuan, Jing [Hong Kong Sanatorium and Hospital, Medical Physics and Research Department, Happy Valley, Hong Kong (China); Wei, Juan [Philips Healthcare Asia, Shanghai (China); Zhou, Jinyuan [Johns Hopkins University, Department of Radiology, Baltimore, MD (United States); Kennedy Krieger Institute, F.M. Kirby Research Center for Functional Brain Imaging, Baltimore, MD (United States)

2016-06-15

To evaluate Chemical Exchange Saturation Transfer (CEST) MRI for liver imaging at 3.0-T. Images were acquired at offsets (n = 41, increment = 0.25 ppm) from -5 to 5 ppm using a TSE sequence with a continuous rectangular saturation pulse. Amide proton transfer-weighted (APTw) and GlycoCEST signals were quantified as the asymmetric magnetization transfer ratio (MTR{sub asym}) at 3.5 ppm and the total MTR{sub asym} integrated from 0.5 to 1.5 ppm, respectively, from the corrected Z-spectrum. Reproducibility was assessed for rats and humans. Eight rats were devoid of chow for 24 hours and scanned before and after fasting. Eleven rats were scanned before and after one-time CCl4 intoxication. For reproducibility, rat liver APTw and GlycoCEST measurements had 95 % limits of agreement of -1.49 % to 1.28 % and -0.317 % to 0.345 %. Human liver APTw and GlycoCEST measurements had 95 % limits of agreement of -0.842 % to 0.899 % and -0.344 % to 0.164 %. After 24 hours, fasting rat liver APTw and GlycoCEST signals decreased from 2.38 ± 0.86 % to 0.67 ± 1.12 % and from 0.34 ± 0.26 % to -0.18 ± 0.37 % respectively (p < 0.05). After CCl4 intoxication rat liver APTw and GlycoCEST signals decreased from 2.46 ± 0.48 % to 1.10 ± 0.77 %, and from 0.34 ± 0.23 % to -0.16 ± 0.51 % respectively (p < 0.05). CEST liver imaging at 3.0-T showed high sensitivity for fasting as well as CCl4 intoxication. (orig.)

On-bead combinatorial synthesis and imaging of chemical exchange saturation transfer magnetic resonance imaging agents to identify factors that influence water exchange.

Science.gov (United States)

Napolitano, Roberta; Soesbe, Todd C; De León-Rodríguez, Luis M; Sherry, A Dean; Udugamasooriya, D Gomika

2011-08-24

The sensitivity of magnetic resonance imaging (MRI) contrast agents is highly dependent on the rate of water exchange between the inner sphere of a paramagnetic ion and bulk water. Normally, identifying a paramagnetic complex that has optimal water exchange kinetics is done by synthesizing and testing one compound at a time. We report here a rapid, economical on-bead combinatorial synthesis of a library of imaging agents. Eighty different 1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid (DOTA)-tetraamide peptoid derivatives were prepared on beads using a variety of charged, uncharged but polar, hydrophobic, and variably sized primary amines. A single chemical exchange saturation transfer image of the on-bead library easily distinguished those compounds having the most favorable water exchange kinetics. This combinatorial approach will allow rapid screening of libraries of imaging agents to identify the chemical characteristics of a ligand that yield the most sensitive imaging agents. This technique could be automated and readily adapted to other types of MRI or magnetic resonance/positron emission tomography agents as well.

Pocket Size Solid State FLASH and iPOD Drives for gigabyte storage, display and transfer of digital medical images: an introduction

International Nuclear Information System (INIS)

Sankaran, A.

2008-01-01

The transition of radiological imaging from analog to digital was closely followed by the development of the Picture Archiving and Communication (PACS) system. Concomitantly, multidimensional imaging ( 4D and 5D, for motion and functional studies on 3D images) have presented new challenges, particularly in handling gigabyte size images from CT, MRI and PET scanners, which generate thousands of images. The storage and analysis of these images necessitate expensive image workstations. This paper highlights the recent innovations in mass storage, display and transfer of images, using miniature/pocket size solid state FLASH and iPOD drives

Liquid-Metal/Water Direct Contact Heat Exchange: Flow Visualization, Flow Stability, and Heat Transfer Using Real-Time X-Ray Imaging

International Nuclear Information System (INIS)

Abdulla, Sherif H.; Liu Xin; Anderson, Mark H.; Bonazza, Riccardo; Corradini, Michael L.; Cho, Dae; Page, Richard

2005-01-01

Advanced reactor system designs are being considered with liquid-metal cooling connected to a steam power cycle. In addition, current reactor safety systems are considering auxiliary cooling schemes that assure ex-vessel debris coolability utilizing direct water injection into molten material pools to achieve core quenching and eventual coolability. The phenomenon common in both applications is direct contact heat exchange. The current study focuses on detailed measurements of liquid-metal/water direct contact heat exchange that is directly applicable to improvements in effective heat transfer in devices that are being considered for both of these purposes.In this study, a test facility was designed at the University of Wisconsin-Madison to map the operating range of liquid-metal/water direct contact heat exchange. The test section (184-cm height, 45.75-cm width, and 10-cm depth) is a rectangular slice of a larger heat exchange device. This apparatus was used not only to provide measurements of integral thermal performance (i.e., volumetric heat transfer coefficient), but also local heat transfer coefficients in a bubbly flow regime with X-ray imaging based on measured parameters such as bubble formation time, bubble rise velocity, and bubble diameters.To determine these local heat transfer coefficients, a complete methodology of the X-ray radiography for two-phase flow measurement has been developed. With this methodology, a high-energy X-ray imaging system is optimized for our heat exchange experiments. With this real-time, large-area, high-energy X-ray imaging system, the two-phase flow was quantitatively visualized. An efficient image processing strategy was developed by combining several optimal digital image-processing algorithms into a software computational tool written in MATLAB called T-XIP. Time-dependent heat transfer-related variables such as bubble volumes and velocities, were determined. Finally, an error analysis associated with these measurements

Towards an ultra-thin medical endoscope: multimode fibre as a wide-field image transferring medium

Science.gov (United States)

Duriš, Miroslav; Bradu, Adrian; Podoleanu, Adrian; Hughes, Michael

2018-03-01

Multimode optical fibres are attractive for biomedical and industrial applications such as endoscopes because of the small cross section and imaging resolution they can provide in comparison to widely-used fibre bundles. However, the image is randomly scrambled by propagation through a multimode fibre. Even though the scrambling is unpredictable, it is deterministic, and therefore the scrambling can be reversed. To unscramble the image, we treat the multimode fibre as a linear, disordered scattering medium. To calibrate, we scan a focused beam of coherent light over thousands of different beam positions at the distal end and record complex fields at the proximal end of the fibre. This way, the inputoutput response of the system is determined, which then allows computational reconstruction of reflection-mode images. However, there remains the problem of illuminating the tissue via the fibre while avoiding back reflections from the proximal face. To avoid this drawback, we provide here the first preliminary confirmation that an image can be transferred through a 2x2 fibre coupler, with the sample at its distal port interrogated in reflection. Light is injected into one port for illumination and then collected from a second port for imaging.

Pathological Assessment of Brain White Matter in Relapsing-Remitting MS Patients using Quantitative Magnetization Transfer Imaging

Directory of Open Access Journals (Sweden)

Khodarahm Pahlevan

2011-09-01

Full Text Available Introduction: Multiple sclerosis (MS is characterized by lesions in the white matter (WM of the central nervous system. Magnetic resonance imaging is the most specific and sensitive method for diagnosis of multiple sclerosis. However, the ability of conventional MRI to show histopathologic heterogeneity of MS lesions is insufficient. Quantitative magnetization transfer imaging (qMTI is a relatively new method to investigate pathologic processes of the brain tissue occurring in MS patients. Material and Methods: Voxel-based analyses allow regional comparisons between groups to be made for the whole brain in a single analysis. This is done by coregistering data from all individual subjects to a reference brain, generally referred to as the "standard space", and then comparing them on a voxel-by-voxel basis. This study aimed to analyze whole-brain quantitative T1 maps, not to find global changes or changes in selected regions, but specifically to investigate the spatial distribution throughout the brain of T1 increases in MS WM with respect to control WM. In this study, 11 healthy controls, 10 relapsing-remitting (RR MS patients and 13 CIS patients were studied using MT-MRI imaging. MT parameters, including magnetization transfer ratio (MTR, magnetization transfer rate between free protons and restricted macromolecular protons, Ksat and longitudinal relaxation times (with and without MT saturation pulse, T1sat and T1free values were evaluated. Results: The results showed that, at a group level, there is widespread involvement of WM throughout the brain in CIS MS and especially in RRMS, where a significant T1 increase was found in 15.58% of WM voxels (normals < RR. Discussion and Conclusion: This study demonstrates that WM in large parts of the brain is susceptible to disease processes in RR and CIS MS

Solitons, Lie Group Analysis and Conservation Laws of a (3+1)-Dimensional Modified Zakharov-Kuznetsov Equation in a Multicomponent Magnetised Plasma

Science.gov (United States)

Du, Xia-Xia; Tian, Bo; Chai, Jun; Sun, Yan; Yuan, Yu-Qiang

2017-11-01

In this paper, we investigate a (3+1)-dimensional modified Zakharov-Kuznetsov equation, which describes the nonlinear plasma-acoustic waves in a multicomponent magnetised plasma. With the aid of the Hirota method and symbolic computation, bilinear forms and one-, two- and three-soliton solutions are derived. The characteristics and interaction of the solitons are discussed graphically. We present the effects on the soliton's amplitude by the nonlinear coefficients which are related to the ratio of the positive-ion mass to negative-ion mass, number densities, initial densities of the lower- and higher-temperature electrons and ratio of the lower temperature to the higher temperature for electrons, as well as by the dispersion coefficient, which is related to the ratio of the positive-ion mass to the negative-ion mass and number densities. Moreover, using the Lie symmetry group theory, we derive the Lie point symmetry generators and the corresponding symmetry reductions, through which certain analytic solutions are obtained via the power series expansion method and the (G'/G) expansion method. We demonstrate that such an equation is strictly self-adjoint, and the conservation laws associated with the Lie point symmetry generators are derived.

An optimized framework for quantitative magnetization transfer imaging of the cervical spinal cord in vivo.

Science.gov (United States)

Battiston, Marco; Grussu, Francesco; Ianus, Andrada; Schneider, Torben; Prados, Ferran; Fairney, James; Ourselin, Sebastien; Alexander, Daniel C; Cercignani, Mara; Gandini Wheeler-Kingshott, Claudia A M; Samson, Rebecca S

2018-05-01

To develop a framework to fully characterize quantitative magnetization transfer indices in the human cervical cord in vivo within a clinically feasible time. A dedicated spinal cord imaging protocol for quantitative magnetization transfer was developed using a reduced field-of-view approach with echo planar imaging (EPI) readout. Sequence parameters were optimized based in the Cramer-Rao-lower bound. Quantitative model parameters (i.e., bound pool fraction, free and bound pool transverse relaxation times [ T2F, T2B], and forward exchange rate [k FB ]) were estimated implementing a numerical model capable of dealing with the novelties of the sequence adopted. The framework was tested on five healthy subjects. Cramer-Rao-lower bound minimization produces optimal sampling schemes without requiring the establishment of a steady-state MT effect. The proposed framework allows quantitative voxel-wise estimation of model parameters at the resolution typically used for spinal cord imaging (i.e. 0.75 × 0.75 × 5 mm 3 ), with a protocol duration of ∼35 min. Quantitative magnetization transfer parametric maps agree with literature values. Whole-cord mean values are: bound pool fraction = 0.11(±0.01), T2F = 46.5(±1.6) ms, T2B = 11.0(±0.2) µs, and k FB  = 1.95(±0.06) Hz. Protocol optimization has a beneficial effect on reproducibility, especially for T2B and k FB . The framework developed enables robust characterization of spinal cord microstructure in vivo using qMT. Magn Reson Med 79:2576-2588, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc

Initial study of magnetization transfer contrast MR imaging of the knee at 3 Tesla

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Yoshioka, Hiroshi; Echigo, Junko; Niitsu, Mamoru; Anno, Izumi; Itai, Yuji [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine; Nakai, Toshiharu; Sato, Hiroshi; Tsukamoto, Tetsuji

1998-10-01

It has been reported that various image sequences, including magnetization transfer contrast (MTC) were effective in evaluating articular cartilage. It is difficult to identify cartilaginous structures, however, using conventional MR imaging because of low spatial resolution and low signal-to-noise (S/N) ratio. The purpose of the present study was to evaluate the optimal imaging sequences with MTC pulse at 3 T and to assess the feasibility of the clinical application thereof. Five porcine knees were studied using varying imaging parameters (frequency offset, flip angle (FA) and echo time (TE)) combined with off-resonance sinc radiation pulses. The effect of MTC was analyzed by dividing the signal intensity of MTC GRE images by that of conventional GRE images (Ms/Mo). MTC images were obtained with a low specific absorption rate (SAR). With an offset frequency of 1.5 kHz (repetition time/TE/FA=60 ms/8 ms/30 degrees), the mean Ms/Mo of articular cartilage and meniscus was 0.70 and 0.65, respectively. An FA of 20 to 30 degrees and a TE of 11 to 12 ms appear to be optimal parameters at 3 T with MTC pulse because of the higher S/N ratio of cartilage and higher contrast-to-noise ratio of cartilage relative to that of distilled water. These findings suggest that MTC at 3 T may be feasible and effective for assessment of cartilage and meniscus in clinical applications. (author)

Data and image transfer using mobile phones to strengthen microscopy-based diagnostic services in low and middle income country laboratories.

Directory of Open Access Journals (Sweden)

Coosje J Tuijn

Full Text Available BACKGROUND: The emerging market of mobile phone technology and its use in the health sector is rapidly expanding and connecting even the most remote areas of world. Distributing diagnostic images over the mobile network for knowledge sharing, feedback or quality control is a logical innovation. OBJECTIVE: To determine the feasibility of using mobile phones for capturing microscopy images and transferring these to a central database for assessment, feedback and educational purposes. METHODS: A feasibility study was carried out in Uganda. Images of microscopy samples were taken using a prototype connector that could fix a variety of mobile phones to a microscope. An Information Technology (IT platform was set up for data transfer from a mobile phone to a website, including feedback by text messaging to the end user. RESULTS: Clear images were captured using mobile phone cameras of 2 megapixels (MP up to 5MP. Images were sent by mobile Internet to a website where they were visualized and feedback could be provided to the sender by means of text message. CONCLUSION: The process of capturing microscopy images on mobile phones, relaying them to a central review website and feeding back to the sender is feasible and of potential benefit in resource poor settings. Even though the system needs further optimization, it became evident from discussions with stakeholders that there is a demand for this type of technology.

Biochemical imaging of cervical intervertebral discs with glycosaminoglycan chemical exchange saturation transfer magnetic resonance imaging: feasibility and initial results

International Nuclear Information System (INIS)

Schleich, Christoph; Mueller-Lutz, Anja; Zimmermann, Lisa; Boos, Johannes; Wittsack, Hans-Joerg; Antoch, Gerald; Miese, Falk; Schmitt, Benjamin

2016-01-01

To evaluate glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging at 3T in the assessment of the GAG content of cervical IVDs in healthy volunteers. Forty-two cervical intervertebral discs of seven healthy volunteers (four females, three males; mean age: 21.4 ± 1.4 years; range: 19-24 years) were examined at a 3T MRI scanner in this prospective study. The MRI protocol comprised standard morphological, sagittal T2 weighted (T2w) images to assess the magnetic resonance imaging (MRI) based grading system for cervical intervertebral disc degeneration (IVD) and biochemical imaging with gagCEST to calculate a region-of-interest analysis of nucleus pulposus (NP) and annulus fibrosus (AF). GagCEST of cervical IVDs was technically successful at 3T with significant higher gagCEST values in NP compared to AF (1.17 % ± 1.03 % vs. 0.79 % ± 1.75 %; p = 0.005). We found topological differences of gagCEST values of the cervical spine with significant higher gagCEST effects in lower IVDs (r = 1; p = 0). We could demonstrate a significant, negative correlation between gagCEST values and cervical disc degeneration of NP (r = -0.360; p = 0.019). Non-degenerated IVDs had significantly higher gagCEST effects compared to degenerated IVDs in NP (1.76 % ± 0.92 % vs. 0.52 % ± 1.17 %; p < 0.001). Biochemical imaging of cervical IVDs is feasible at 3T. GagCEST analysis demonstrated a topological GAG distribution of the cervical spine. The depletion of GAG in the NP with increasing level of morphological degeneration can be assessed using gagCEST imaging. (orig.)

Measurement of the presampled two-dimensional modulation transfer function of digital imaging systems

International Nuclear Information System (INIS)

Fetterly, Kenneth A.; Hangiandreou, Nicholas J.; Schueler, Beth A.; Ritenour, E. Russell

2002-01-01

The purpose of this work was to develop methods to measure the presampled two-dimensional modulation transfer function (2D MTF) of digital imaging systems. A custom x-ray 'point source' phantom was created by machining 256 holes with diameter 0.107 mm through a 0.5-mm-thick copper plate. The phantom was imaged several times, resulting in many images of individual x-ray 'spots'. The center of each spot (with respect to the pixel matrix) was determined to subpixel accuracy by fitting each spot to a 2D Gaussian function. The subpixel spot center locations were used to create a 5x oversampled system point spread function (PSF), which characterizes the optical and electrical properties of the system and is independent of the pixel sampling of the original image. The modulus of the Fourier transform of the PSF was calculated. Next, the Fourier function was normalized to the zero frequency value. Finally, the Fourier transform function was divided by the first-order Bessel function that defined the frequency content of the holes, resulting in the presampled 2D MTF. The presampled 2D MTF of a 0.1 mm pixel pitch computed radiography system and 0.2 mm pixel pitch flat panel digital imaging system that utilized a cesium iodide scintillator was measured. Comparison of the axial components of the 2D MTF to one-dimensional MTF measurements acquired using an edge device method demonstrated that the two methods produced consistent results

The progress in diagnostic imaging for staging of bladder and prostate cancer. Endorectal magnetic resonance imaging and magnetization transfer contrast

International Nuclear Information System (INIS)

Arima, Kiminobu; Hayashi, Norio; Yanagawa, Makoto; Kawamura, Juichi; Kobayashi, Shigeki; Takeda, Kan; Sugimura, Yoshiki

1999-01-01

We retrospectively studied the staging accuracy of endorectal magnetic resonance imaging (MRI) in comparison with transrectal ultrasound examination (TRUS) for 71 localized bladder cancers and 19 localized prostate cancers (PC) radically resected. The accuracy of clinical staging for bladder cancer in endorectal MRI and TRUS was 85.9% and 69.2%, respectively. The presence or absence of the continuity of submucosal enhancement on T2-weighted MRI images could be useful for the staging of bladder cancer. The accuracy of the seminal vesicular invasion for prostate cancer in endorectal MRI and TRUS was 95% and 63%, respectively. To determine whether magnetization transfer contrast (MTC) provides additional information in the diagnosis of prostate cancer, the magnetization transfer ratios (MTRs) were calculated in 22 patients with PC, 5 with benign prostatic hyperplasia (BPH) and 4 controls. The mean MTR in the peripheral zone of the normal prostate (8.0%±3.4 [standard deviation]) showed a statistically significant decrease relative to that in the inner zone of the normal prostate (27.4%±3.4, p<0.01), BPH (25.5%±3.7, p<0.01), pre-treatment PC (30.6%±5.9, p<0.01), and PC after hormonal therapy (20.3%±6.3, p<0.01). The mean MTR in pre-treatment PC was significantly higher than that in BPH, or in PC after hormonal therapy (p<0.01). MTC was considered to be useful for conspicuity of prostate cancer lesion. (author)

Postcontrast T1-weighted brain magnetic resonance imaging in pediatric patients: comparison between postcontrast fat-suppression imaging and conventional T1-weighted or magnetization transfer imaging

International Nuclear Information System (INIS)

Lee, Choong Wook; Goo, Hyun Woo

2004-01-01

We wished to assess the merits and weaknesses of postcontrast fat-suppression (FS) brain MR imaging in children for the evaluation of various enhancing lesions as compared with postcontrast conventional T1-weighted or magnetization transfer (MT) imaging. We reviewed the records of those patients with enhancing lesions on brain MR imaging who had undergone both FS imaging and one of the conventional T1-weighted or MT imaging as a post-contrast T1-weighted brain MR imaging. Thirty-one patients (21 male, 10 female; mean age, 8.7 years) with 38 enhancing lesions (18 intra-axial, 16 extra-axial and 4 orbital locations) were included in this study. There were 27 pairs of FS and conventional imagings, and 13 pairs of FS and MT imagings available for evaluation. Two radiologists visually assessed by consensus the lesions' conspicuity, and they also looked for the presence of flow or susceptibility artifacts in a total of 40 pairs of MR imagings. For 19 measurable lesions (14 pairs of FS and conventional T1-weighted imagings, 5 pairs of FS and MT imagings), the contrast ratios between the lesion and the normal brain ([SIlesion-SIwater]/[SInormal brain-SIwater]) were calculated and compared. Compared with conventional imaging, the lesion conspicuity on FS imaging was better in 10 cases (7 extra-axial lesions, 2 orbital lesions and 1 fat-containing intra-axial lesion), equal in 16 cases, and worse in one case. Compared with MT imaging, the lesion conspicuity on FS imaging was better in 3 cases (2 extra-axial lesions and 1 intra-axial lesion), equal in 8 cases, and worse in 2 cases. Image quality of FS imaging was compromised by flow or susceptibility artifacts for 7 patients. The contrast ratios for FS imaging were not significantly different from those for conventional imaging (2.2±0.7 vs. 2.2±0.6, respectively, p=0.914) and they were significantly lower than those for MT imaging (2.4±0.8 vs. 4.5±1.5, respectively, p=0.018). Postcontrast FS brain MR imaging appears to be

Variation of the count-dependent Metz filter with imaging system modulation transfer function

International Nuclear Information System (INIS)

King, M.A.; Schwinger, R.B.; Penney, B.C.

1986-01-01

A systematic investigation was conducted of how a number of parameters which alter the system modulation transfer function (MTF) influence the count-dependent Metz filter. Since restoration filters are most effective at those frequencies where the object power spectrum dominates that of the noise, it was observed that parameters which significantly degrade the MTF at low spatial frequencies strongly influence the formation of the Metz filter. Thus the radionuclide imaged and the depth of the source in a scattering medium had the most influence. This is because they alter the relative amount of scattered radiation being imaged. For low-energy photon emitters, the collimator employed and the distance from the collimator were found to have less of an influence but still to be significant. These cause alterations in the MTF which are more gradual, and hence are most pronounced at mid to high spatial frequencies. As long as adequate spatial sampling is employed, the Metz filter was determined to be independent of the exact size of the sampling bin width, to a first approximation. For planar and single photon emission computed tomographic (SPECT) imaging, it is shown that two-dimensional filtering with the Metz filter optimized for the imaging conditions is able to deconvolve scatter and other causes of spatial resolution loss while diminishing noise, all in a balanced manner

Enhancement system of nighttime infrared video image and visible video image

Science.gov (United States)

Wang, Yue; Piao, Yan

2016-11-01

Visibility of Nighttime video image has a great significance for military and medicine areas, but nighttime video image has so poor quality that we can't recognize the target and background. Thus we enhance the nighttime video image by fuse infrared video image and visible video image. According to the characteristics of infrared and visible images, we proposed improved sift algorithm andαβ weighted algorithm to fuse heterologous nighttime images. We would deduced a transfer matrix from improved sift algorithm. The transfer matrix would rapid register heterologous nighttime images. And theαβ weighted algorithm can be applied in any scene. In the video image fusion system, we used the transfer matrix to register every frame and then used αβ weighted method to fuse every frame, which reached the time requirement soft video. The fused video image not only retains the clear target information of infrared video image, but also retains the detail and color information of visible video image and the fused video image can fluency play.

Retrieval of spruce leaf chlorophyll content from airborne image data using continuum removal and radiative transfer

Czech Academy of Sciences Publication Activity Database

Malenovský, Z.; Homolová, L.; Zurita-Milla, R.; Lukeš, Petr; Kaplan, Věroslav; Hanuš, Jan; Gastellu-Etchegory, J.P.; Schaepman, M.E.

2013-01-01

Roč. 131, APR (2013), s. 85-102 ISSN 0034-4257 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) LM2010007 Institutional support: RVO:67179843 Keywords : Chlorophyll retrieval * Imaging spectroscopy * Continuum removal * Radiative transfer * PROSPECT * DART * Optical indices * Norway spruce * High spatial resolution * AISA Subject RIV: EH - Ecology, Behaviour Impact factor: 4.769, year: 2013

Transferring biomarker into molecular probe: melanin nanoparticle as a naturally active platform for multimodality imaging.

Science.gov (United States)

Fan, Quli; Cheng, Kai; Hu, Xiang; Ma, Xiaowei; Zhang, Ruiping; Yang, Min; Lu, Xiaomei; Xing, Lei; Huang, Wei; Gambhir, Sanjiv Sam; Cheng, Zhen

2014-10-29

Developing multifunctional and easily prepared nanoplatforms with integrated different modalities is highly challenging for molecular imaging. Here, we report the successful transfer of an important molecular target, melanin, into a novel multimodality imaging nanoplatform. Melanin is abundantly expressed in melanotic melanomas and thus has been actively studied as a target for melanoma imaging. In our work, the multifunctional biopolymer nanoplatform based on ultrasmall (passive nanoplatforms require complicated and time-consuming processes for prebuilding reporting moieties or chemical modifications using active groups to integrate different contrast properties into one entity. In comparison, utilizing functional biomarker melanin can greatly simplify the building process. We further conjugated αvβ3 integrins, cyclic c(RGDfC) peptide, to MNPs to allow for U87MG tumor accumulation due to its targeting property combined with the enhanced permeability and retention (EPR) effect. The multimodal properties of MNPs demonstrate the high potential of endogenous materials with multifunctions as nanoplatforms for molecular theranostics and clinical translation.

A Novel Image Encryption Scheme Based on Clifford Attractor and Noisy Logistic Map for Secure Transferring Images in Navy

Directory of Open Access Journals (Sweden)

Mohadeseh Kanafchian

2017-04-01

In this paper, we first give a brief introduction into chaotic image encryption and then we investigate some important properties and behaviour of the logistic map. The logistic map, aperiodic trajectory, or random-like fluctuation, could not be obtained with some choice of initial condition. Therefore, a noisy logistic map with an additive system noise is introduced. The proposed scheme is based on the extended map of the Clifford strange attractor, where each dimension has a specific role in the encryption process. Two dimensions are used for pixel permutation and the third dimension is used for pixel diffusion. In order to optimize the Clifford encryption system we increase the space key by using the noisy logistic map and a novel encryption scheme based on the Clifford attractor and the noisy logistic map for secure transfer images is proposed. This algorithm consists of two parts: the noisy logistic map shuffle of the pixel position and the pixel value. We use times for shuffling the pixel position and value then we generate the new pixel position and value by the Clifford system. To illustrate the efficiency of the proposed scheme, various types of security analysis are tested. It can be concluded that the proposed image encryption system is a suitable choice for practical applications.

Enhanced imaging of magnetic structures in micropatterned arrays of Co dots and antidots

Energy Technology Data Exchange (ETDEWEB)

Chiolerio, Alessandro [Physics Department Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Celasco, Edvige [Physics Department Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Materials and Microsystems Laboratory (chi lab)-LATEMAR Unit, Lungo Piazza d' Armi 6, Chivasso (Torino) (Italy); Celegato, Federica [INRIM, Strada delle Cacce 91, 10138 Torino (Italy); Guastella, Salvatore; Martino, Paola [Physics Department Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Allia, Paolo [Physics Department Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)], E-mail: paolo.allia@polito.it; Tiberto, Paola [INRIM, Strada delle Cacce 91, 10138 Torino (Italy); Pirri, Fabrizio [Physics Department Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Materials and Microsystems Laboratory (chi lab)-LATEMAR Unit, Lungo Piazza d' Armi 6, Chivasso (Torino) (Italy)

2008-10-15

A specific technique of numerical treatment of atomic force microscopy (AFM) and magnetic force microscopy (MFM) signal has been developed to enhance the quality of raw images, in order both to improve their contrast and to gain better insight on the sample topography and on the local arrangement of the magnetisation vector. Basically, the technique consists in computing the optimum conformal transformation that allows one to superimpose two AFM images of the same area, acquired performing subsequent scans whose fast scan axis were mutually perpendicular, and applying the inverse transform to the second image. After MFM image superposition, the two datasets were either summed or subtracted, in order to improve the magnetic contrast. Computations have been done in a Matlab workspace with the help of Image Processing Toolbox 4.2. Improved MFM images obtained on both dots and antidots thin evaporated Co arrays in the demagnetised state (after performing alternate field demagnetisation parallel and perpendicular to the array plane) have been interpreted. Samples consisting of large-size patterns (1x1 mm) of circular dots/antidots with square/hexagonal lattices and minimum diameters of 1 {mu}m were prepared by optical lithography. The magnetic film thickness was chosen depending on resist thickness, and varied between 25 and 150 nm, with a fixed ratio 1:4 between metal/resist film thickness. MFM was exploited to obtain images of either intra-dot or inter-antidot magnetic structures.

Conversion from film to image plates for transfer method neutron radiography of nuclear fuel

Energy Technology Data Exchange (ETDEWEB)

Craft, Aaron E.; Papaioannou, Glen C.; Chichester, David L.; Williams, Walter J.

2017-02-01

This paper summarizes efforts to characterize and qualify a computed radiography (CR) system for neutron radiography of irradiated nuclear fuel at Idaho National Laboratory (INL). INL has multiple programs that are actively developing, testing, and evaluating new nuclear fuels. Irradiated fuel experiments are subjected to a number of sequential post-irradiation examination techniques that provide insight into the overall behavior and performance of the fuel. One of the first and most important of these exams is neutron radiography, which provides more comprehensive information about the internal condition of irradiated nuclear fuel than any other non-destructive technique to date. Results from neutron radiography are often the driver for subsequent examinations of the PIE program. Features of interest that can be evaluated using neutron radiography include irradiation-induced swelling, isotopic and fuel-fragment redistribution, plate deformations, and fuel fracturing. The NRAD currently uses the foil-film transfer technique with film for imaging fuel. INL is pursuing multiple efforts to advance its neutron imaging capabilities for evaluating irradiated fuel and other applications, including conversion from film to CR image plates. Neutron CR is the current state-of-the-art for neutron imaging of highly-radioactive objects. Initial neutron radiographs of various types of nuclear fuel indicate that radiographs can be obtained of comparable image quality currently obtained using film. This paper provides neutron radiographs of representative irradiated fuel pins along with neutron radiographs of standards that informed the qualification of the neutron CR system for routine use. Additionally, this paper includes evaluations of some of the CR scanner parameters and their effects on image quality.

A theory of frequency domain invariants: spherical harmonic identities for BRDF/lighting transfer and image consistency.

Science.gov (United States)

Mahajan, Dhruv; Ramamoorthi, Ravi; Curless, Brian

2008-02-01

This paper develops a theory of frequency domain invariants in computer vision. We derive novel identities using spherical harmonics, which are the angular frequency domain analog to common spatial domain invariants such as reflectance ratios. These invariants are derived from the spherical harmonic convolution framework for reflection from a curved surface. Our identities apply in a number of canonical cases, including single and multiple images of objects under the same and different lighting conditions. One important case we consider is two different glossy objects in two different lighting environments. For this case, we derive a novel identity, independent of the specific lighting configurations or BRDFs, that allows us to directly estimate the fourth image if the other three are available. The identity can also be used as an invariant to detecttampering in the images. While this paper is primarily theoretical, it has the potential to lay the mathematical foundations for two important practical applications. First, we can develop more general algorithms for inverse rendering problems, which can directly relight and change material properties by transferring the BRDF or lighting from another object or illumination. Second, we can check the consistency of an image, to detect tampering or image splicing.

The Rejuvenating Effect in Hot Asphalt Recycling by Mortar Transfer Ratio and Image Analysis.

Science.gov (United States)

Wang, Fusong; Wang, Zipeng; Li, Chao; Xiao, Yue; Wu, Shaopeng; Pan, Pan

2017-05-24

Using a rejuvenator to improve the performance of asphalt pavement is an effective and economic way of hot asphalt recycling. This research analyzes the rejuvenating effect on aged asphalt by means of a Mortar Transfer Ratio (MTR) test, which concerns the ratio of asphalt mortar that moves from recycled aggregates (RAP aggregates) to fresh added aggregates when aged asphalt is treated with a regenerating agent and comes into contact with fresh aggregates. The proposed MTR test analyzes the regeneration in terms of the softening degree on aged asphalt when the rejuvenator is applied. The covered area ratio is studied with an image analyzing tool to understand the possibility of mortar transferring from RAP aggregates to fresh aggregates. Additionally, a micro-crack closure test is conducted and observed through a microscope. The repairing ability and diffusion characteristics of micro-cracks can therefore be analyzed. The test results demonstrate that the proposed mortar transfer ratio is a feasible way to evaluate rejuvenator diffusion during hot recycling. The mortar transfer ratio and uncovered area ratio on fresh aggregates are compatible, and can be used to quantify the contribution of the rejuvenator. Within a certain temperature range, the diffusing effect of the rejuvenator is better when the diffusing temperature is higher. The diffusion time of the rejuvenator is optimum when diffusion occurs for 4-8 h. When the rejuvenator is properly applied, the rough and cracking surface can be repaired, resulting in better covered aggregates. The micro-closure analysis visually indicates that rejuvenators can be used to repair the RAP aggregates during hot recycling.

Simulation of Sentinel-3 images by four stream surface atmosphere radiative transfer modeling in the optical and thermal domains

NARCIS (Netherlands)

Verhoef, W.; Bach, H.

2012-01-01

Simulation of future satellite images can be applied in order to validate the general mission concept and to test the performance of advanced multi-sensor algorithms for the retrieval of surface parameters. This paper describes the radiative transfer modeling part of a so-called Land Scene Generator

Magnetization transfer and spin lock MR imaging of patellar cartilage degeneration at 0.1 T

International Nuclear Information System (INIS)

Koskinen, S.K.; Ylae-Outinen, H.; Komu, M.E.S.; Aho, H.J.

1997-01-01

Purpose: To investigate magnetization transfer (MT) parameters and rotating frame relaxation time T1ρ in patellar cartilage at different levels of degeneration. Material and Methods: Thirty cadaveric patellae were examined at 0.1 T using the time-dependent saturation-transfer MT technique and the spin lock (SL) technique. In an SL experiment, nuclear spins are locked with a radiofrequency (RF) field, and the locked nuclear magnetization relaxes along the magnetic component of the locking RF field. The specimens were divided into three groups according to the level of cartilage degeneration. MT parameters and T1ρ were measured. Results: The MT effect was greater in degenerated cartilage than in normal cartilage. T1ρ was longer in advanced cartilage degeneration than in intermediate cartilage degeneration. Conculsion: The results suggest that more studies are needed to fully establish the value of SL imaging in cartilage degeneration. (orig.)

Conception and data transfer analysis of an open-source digital image archive designed for radiology

International Nuclear Information System (INIS)

Teichgraeber, U.K.M.; Lehmkuhl, L.; Harderer, A.; Emmel, D.; Ehrenstein, T.; Ricke, J.; Felix, R.

2003-01-01

Purpose: Implementation of a self-designed, web-based digital image archive incorporating the existing DICOM infrastructure to assure distribution of digital pictures and reports and to optimize work flow. Assessment after three years. Materials and methods: Open-source software was used to guarantee highest reliability and cost effectiveness. In view of rapidly increasing capacity and decreasing costs of hard discs (HDs), HDs were preferred over slower and expensive magneto-optical disk (MOD) or tape storage systems. The number of installed servers increased from one to 12. By installing HDs with increased capacities, the number of servers should be kept constant. Entry and access of data were analyzed over two 4-month periods (after 1.5 and 2 years of continuous operations). Results: Our digital image archive was found to be very reliable, cost effective and suitable for its designated tasks. As judged from the measured access volume, the average utilization of the system increased by 160%. In the period from January to April 2002, the users accessed 239.8 gigabyte of the stored 873.7 gigabyte image data (27%). The volume of the stored data added 20%, mainly due to an increase in cross-section imaging. Conclusion: The challenge of developing a digital image archive with limited financial resources resulted in a practicable and expandable solution. The utilization, number of active users and volume of transferred data have increased significantly. Our concept of utilizing HDs for image storage proved to be successful. (orig.) [de

Anatomy of the Java plate interface from depth-migrated seismic images: Implications for sediment transfer

Science.gov (United States)

Kopp, H.; Hindle, D.; Klaeschen, D.; Oncken, O.; Reichert, C.; Scholl, D.

2008-12-01

We present seismic data from the western Java margin off Indonesia. The newly pre-stack depth migrated seismic images resolve the structural details of the western Java forearc and the fate of sediment subducted at the trench. Approximately 2/3 of the trench sediment fill is detached and incorporated into frontal prism imbricates, while the floor sequence is transported down a subduction channel. Basal mass transfer occurs by episodic accretion of sediment beneath the submerged forearc as the active detachment stepwise descends to a deeper level below the outer wedge. Fluctuations in subduction channel dimensions are enhanced by deep-reaching thrust faults that are traced from a velocity singularity marking the top of the oceanic basement towards the seafloor. These thrust faults breach the subduction channel and inhibit recycling of material to mantle depth, while serving as an incremental ramp along which the active detachment is transferred to a lower position. The high ratio of accreted/subducted sediment is associated with the evolution of a large bivergent wedge (>100 km) despite the comparatively low sediment input to the trench (<2 km). We used quantitative DEM modeling to gain some insight into the evolution of the distinct tectonic units. In the modelling, initiation of sediment accretion occurs against the arc rock framework, which is imaged in the MCS data. Overthrusting of the wedge onto the forearc basin is also expressed in a prominent retro-thrust imaged in the seismic data. The seismic data document an end-member type of subduction zone where near-complete accretion of the trench sediment fill by frontal and basal accretion is supported by the lack of evidence for subducted sediment in the geochemical signature of Mt. Guntur and Mt. Gallunggung, two volcanoes positioned in the prolongation of our seismic line on Java.

Chemical Exchange Saturation Transfer MR Imaging Is Superior to Diffusion Tensor Imaging in the Diagnosis and Severity Evaluation of Parkinson's Disease: a Study on Substantia Nigra and Striatum

Directory of Open Access Journals (Sweden)

Chunmei eLi

2015-10-01

Full Text Available Parkinson’s disease (PD is a neurodegenerative disorder characterized by nigrostriatal cell loss. To date the diagnosis of PD is still based primarily on the clinical manifestations which may be typical and obvious only in advanced-stage PD. Thus, it is crucial to find a reliable marker for the diagnosis of PD. We conducted this study to assess the diagnostic efficiency of chemical-exchange-saturation-transfer (CEST imaging and diffusion-tensor imaging (DTI in PD at 3 Tesla by evaluating changes on substantia nigra and striatum. Twenty-three PD patients and twenty-three age-matched normal controls were recruited. All patients and controls were imaged on a 3 Tesla MR system, using an 8-channel head coil. CEST imaging was acquired in two transverse slices of the head, including substantia nigra and striatum. The magnetization-transfer-ratio asymmetry at 3.5 ppm, MTRasym(3.5ppm, and the total CEST signal intensity between 0 and 4 ppm were calculated. Multi-slice DTI was acquired for all the patients and normal controls. Quantitative analysis was performed on the substantia nigra, globus pallidus, putamen and caudate. The MTRasym(3.5ppm value, the total CEST signal intensity and fractional anisotropy (FA value of the substantia nigra were all significantly lower in PD patients than in normal controls (P = 0.003, P = 0.004 and P < 0.001, respectively. The MTRasym(3.5ppm values of the putamen and the caudate were significantly higher in PD patients than in normal controls (P = 0.010 and P = 0.009, respectively. There were no significant differences for the mean diffusivity (MD in these four regions between PD patients and normal controls. In conclusion, CEST MR imaging provided multiple CEST image contrasts in the substantia nigra and the striatum in PD and may be superior to DTI in the diagnosis of PD.

The Assessment of Structural Changes in MS Plaques and Normal Appearing White Matter Using Quantitative Magnetization Transfer Imaging (MTI

Directory of Open Access Journals (Sweden)

Masoomeh Fooladi

2007-12-01

Full Text Available Introduction: Multiple sclerosis (MS is a demyelinating disease of the central nervous system (CNS, affecting mostly young people at a mean age of 30 years. Magnetic resonance imaging (MRI is one of the most specific and sensitive methods in diagnosing and detecting the evolution of multiple sclerosis disease. But it does not have the ability to differentiate between distinct histopathological heterogeneities that occur in MS lesions and brain tissue.Quantitative magnetization transfer imaging (qMTI is a relatively new MRI technique which can be used to examine the pathological processes of the brain parenchyma which occur in MS patients.This quantitative MRI technique can provide more complete information about the extent and nature of the brain tissue destruction in multiple sclerosis, which cannot be detected by conventional MRI. Material and Methods: In this study, twelve patients with relapsing-remitting MS and twelve healthy control subjects underwent conventional MR imaging including: T2-FSE, T1-SE and FLAIR sequences as well as quantitative magnetization transfer imaging. All the focal lesions were identified on T2-weighted images and were classified according to their signal hypointensity on T1-weighted scans. The white matter and MS lesions were segmented using a semi-automated system. MT ratio (MTR histogram analysis was performed for the brain white matter and the average MTR value was calculated for the classified MS lesions. Results: A significant reduction was found in MTR value of the normal appearing white matter (NAWM in patients with relapsing-remitting MS, suggesting that MS is a more diffuse disease, affecting the whole brain tissue. A wide range changes in MTR values can be observed in MS lesions. MTR reduction is correlated with the degree of lesion hypointensity on T1-weighted scans. The lower MTR values of lesions that appear progressively more hypointense on T1-weigted images reflect varying degrees of demyelination and

Net-based data transfer and automatic image fusion of metabolic (PET) and morphologic (CT/MRI) images for radiosurgical planning of brain tumors

International Nuclear Information System (INIS)

Baum, R.P.; Przetak, C.; Schmuecking, M.; Klener, G.; Surber, G.; Hamm, K.

2002-01-01

Aim: The main purpose of radiosurgery in comparison to conventional radiotherapy of brain tumors is to reach a higher radiation dose in the tumor and sparing normal brain tissue as much as possible. To reach this aim it is crucial to define the target volume extremely accurately. For this purpose, MRI and CT examinations are used for radiotherapy planning. In certain cases, however, metabolic information obtained by positron emission tomography (PET) may be useful to achieve a higher therapeutic accuracy by sparing important brain structures. This can be the case, i.e. in low grade astrocytomas for exact delineation of vital tumor as well as in differentiating scaring tissue from tumor recurrence and edema after operation. For this purpose, radiolabeled aminoacid analogues (e.g. C-11 methionine) and recently O-2-[ 18 F] Fluorethyl-L-Tyrosin (F-18 FET) have been introduced as PET tracers to detect the area of highest tumor metabolism which allows to obtain additional information as compared to FDG-PET that reflects the local glucose metabolism. In these cases, anatomical and metabolic data have to be combined with the technique of digital image fusion to exactly determine the target volume, the isodoses and the area where the highest dose has to be applied. Materials: We have set up a data transfer from the PET Center of the Zentralklinik Bad Berka with the Department of Stereotactic Radiation at the Helios Klinik Erfurt (distance approx. 25 km) to enable this kind of image fusion. PET data (ECAT EXACT 47, Siemens/CTI) are transferred to a workstation (NOVALIS) in the Dept. of Stereotactic Radiation to be co-registered with the CT or MRI data of the patient. All PET images are in DICOM format (obtained by using a HERMES computer, Nuclear Diagnostics, Sweden) and can easily be introduced into the NOVALIS workstation. The software uses the optimation of mutual information to achieve a good fusion quality. Sometimes manual corrections have to be performed to get an

Radiopharmaceuticals to monitor gene transfer

International Nuclear Information System (INIS)

Wiebe, L. I.; Morin, K. W.; Knaus, E. E.

1997-01-01

Advances in genetic engineering and molecular biology have opened the door to disease treatment by transferring genes to cells that are responsible for the pathological condition being addressed. These genes can serve to supplement or introduce the function of indigenous genes that are either inadequately expressed or that are congenitally absent in the patient. They can introduce new functions such as drug sensitization to provide a unique therapeutic target. Gene transfer is readily monitored in vitro using a range of histochemical and biochemical tests that are ''built in'' to the therapeutic gene cassette. In vivo, in situ monitoring of the gene transfer and gene expression processes can be achieved with these tests only if biopsy is possible. Scintigraphic imaging can offer unique information on both the extent and location of gene expression, provided that an appropriate reporter gene is included in the therapeutic cassette. This overview includes a brief orientation to gene transfer therapy and is followed by a review of current approaches to gene therapy imaging. The concluding section deals with imaging based on radiolabelled nucleoside substrates for herpes simplex type-1 thymidine kinase, with emphasis on IVFRU, a stable potent and selective HSV-1 TK substrate developed in their laboratories

Targeted molecular imaging

International Nuclear Information System (INIS)

Kim, E. Edmund

2003-01-01

Molecular imaging aims to visualize the cellular and molecular processes occurring in living tissues, and for the imaging of specific molecules in vivo, the development of reporter probes and dedicated imaging equipment is most important. Reporter genes can be used to monitor the delivery and magnitude of therapeutic gene transfer, and the time variation involved. Imaging technologies such as micro-PET, SPECT, MRI and CT, as well as optical imaging systems, are able to non-invasively detect, measure, and report the simultaneous expression of multiple meaningful genes. It is believed that recent advances in reporter probes, imaging technologies and gene transfer strategies will enhance the effectiveness of gene therapy trials

Chemical exchange saturation transfer (CEST) MR technique for in-vivo liver imaging at 3.0 tesla.

Science.gov (United States)

Chen, Shu-Zhong; Yuan, Jing; Deng, Min; Wei, Juan; Zhou, Jinyuan; Wáng, Yì-Xiáng J

2016-06-01

To evaluate Chemical Exchange Saturation Transfer (CEST) MRI for liver imaging at 3.0-T. Images were acquired at offsets (n = 41, increment = 0.25 ppm) from -5 to 5 ppm using a TSE sequence with a continuous rectangular saturation pulse. Amide proton transfer-weighted (APTw) and GlycoCEST signals were quantified as the asymmetric magnetization transfer ratio (MTRasym) at 3.5 ppm and the total MTRasym integrated from 0.5 to 1.5 ppm, respectively, from the corrected Z-spectrum. Reproducibility was assessed for rats and humans. Eight rats were devoid of chow for 24 hours and scanned before and after fasting. Eleven rats were scanned before and after one-time CCl4 intoxication. For reproducibility, rat liver APTw and GlycoCEST measurements had 95 % limits of agreement of -1.49 % to 1.28 % and -0.317 % to 0.345 %. Human liver APTw and GlycoCEST measurements had 95 % limits of agreement of -0.842 % to 0.899 % and -0.344 % to 0.164 %. After 24 hours, fasting rat liver APTw and GlycoCEST signals decreased from 2.38 ± 0.86 % to 0.67 ± 1.12 % and from 0.34 ± 0.26 % to -0.18 ± 0.37 % respectively (p 3.0-T showed high sensitivity for fasting as well as CCl4 intoxication. • CEST MRI of in-vivo liver was demonstrated at clinical 3 T field strength. • After 24-hour fasting, rat liver APTw and GlycoCEST signals decreased significantly. • After CCl4 intoxication both rat liver APTw and GlycoCEST signals decreased significantly. • Good scan-rescan reproducibility of liver CEST MRI was shown in healthy volunteers.

Cellular transfer of magnetic nanoparticles via cell microvesicles: impact on cell tracking by magnetic resonance imaging.

Science.gov (United States)

Silva, Amanda K Andriola; Wilhelm, Claire; Kolosnjaj-Tabi, Jelena; Luciani, Nathalie; Gazeau, Florence

2012-05-01

Cell labeling with magnetic nanoparticles can be used to monitor the fate of transplanted cells in vivo by magnetic resonance imaging. However, nanoparticles initially internalized in administered cells might end up in other cells of the host organism. We investigated a mechanism of intercellular cross-transfer of magnetic nanoparticles to different types of recipient cells via cell microvesicles released under cellular stress. Three cell types (mesenchymal stem cells, endothelial cells and macrophages) were labeled with 8-nm iron oxide nanoparticles. Then cells underwent starvation stress, during which they produced microvesicles that were subsequently transferred to unlabeled recipient cells. The analysis of the magnetophoretic mobility of donor cells indicated that magnetic load was partially lost under cell stress. Microvesicles shed by stressed cells participated in the release of magnetic label. Moreover, such microvesicles were uptaken by naïve cells, resulting in cellular redistribution of nanoparticles. Iron load of recipient cells allowed their detection by MRI. Cell microvesicles released under stress may be disseminated throughout the organism, where they can be uptaken by host cells. The transferred cargo may be sufficient to allow MRI detection of these secondarily labeled cells, leading to misinterpretations of the effectiveness of transplanted cells.

Transfer, imaging, and analysis plate for facile handling of 384 hanging drop 3D tissue spheroids.

Science.gov (United States)

Cavnar, Stephen P; Salomonsson, Emma; Luker, Kathryn E; Luker, Gary D; Takayama, Shuichi

2014-04-01

Three-dimensional culture systems bridge the experimental gap between in vivo and in vitro physiology. However, nonstandardized formation and limited downstream adaptability of 3D cultures have hindered mainstream adoption of these systems for biological applications, especially for low- and moderate-throughput assays commonly used in biomedical research. Here we build on our recent development of a 384-well hanging drop plate for spheroid culture to design a complementary spheroid transfer and imaging (TRIM) plate. The low-aspect ratio wells of the TRIM plate facilitated high-fidelity, user-independent, contact-based collection of hanging drop spheroids. Using the TRIM plate, we demonstrated several downstream analyses, including bulk tissue collection for flow cytometry, high-resolution low working-distance immersion imaging, and timely reagent delivery for enzymatic studies. Low working-distance multiphoton imaging revealed a cell type-dependent, macroscopic spheroid structure. Unlike ovarian cancer spheroids, which formed loose, disk-shaped spheroids, human mammary fibroblasts formed tight, spherical, and nutrient-limited spheroids. Beyond the applications we describe here, we expect the hanging drop spheroid plate and complementary TRIM plate to facilitate analyses of spheroids across the spectrum of throughput, particularly for bulk collection of spheroids and high-content imaging.

Two-dimensional pixel image lag simulation and optimization in a 4-T CMOS image sensor

Energy Technology Data Exchange (ETDEWEB)

Yu Junting; Li Binqiao; Yu Pingping; Xu Jiangtao [School of Electronics Information Engineering, Tianjin University, Tianjin 300072 (China); Mou Cun, E-mail: xujiangtao@tju.edu.c [Logistics Management Office, Hebei University of Technology, Tianjin 300130 (China)

2010-09-15

Pixel image lag in a 4-T CMOS image sensor is analyzed and simulated in a two-dimensional model. Strategies of reducing image lag are discussed from transfer gate channel threshold voltage doping adjustment, PPD N-type doping dose/implant tilt adjustment and transfer gate operation voltage adjustment for signal electron transfer. With the computer analysis tool ISE-TCAD, simulation results show that minimum image lag can be obtained at a pinned photodiode n-type doping dose of 7.0 x 10{sup 12} cm{sup -2}, an implant tilt of -2{sup 0}, a transfer gate channel doping dose of 3.0 x 10{sup 12} cm{sup -2} and an operation voltage of 3.4 V. The conclusions of this theoretical analysis can be a guideline for pixel design to improve the performance of 4-T CMOS image sensors. (semiconductor devices)

[A Method to Reconstruct Surface Reflectance Spectrum from Multispectral Image Based on Canopy Radiation Transfer Model].

Science.gov (United States)

Zhao, Yong-guang; Ma, Ling-ling; Li, Chuan-rong; Zhu, Xiao-hua; Tang, Ling-li

2015-07-01

Due to the lack of enough spectral bands for multi-spectral sensor, it is difficult to reconstruct surface retlectance spectrum from finite spectral information acquired by multi-spectral instrument. Here, taking into full account of the heterogeneity of pixel from remote sensing image, a method is proposed to simulate hyperspectral data from multispectral data based on canopy radiation transfer model. This method first assumes the mixed pixels contain two types of land cover, i.e., vegetation and soil. The sensitive parameters of Soil-Leaf-Canopy (SLC) model and a soil ratio factor were retrieved from multi-spectral data based on Look-Up Table (LUT) technology. Then, by combined with a soil ratio factor, all the parameters were input into the SLC model to simulate the surface reflectance spectrum from 400 to 2 400 nm. Taking Landsat Enhanced Thematic Mapper Plus (ETM+) image as reference image, the surface reflectance spectrum was simulated. The simulated reflectance spectrum revealed different feature information of different surface types. To test the performance of this method, the simulated reflectance spectrum was convolved with the Landsat ETM + spectral response curves and Moderate Resolution Imaging Spectrometer (MODIS) spectral response curves to obtain the simulated Landsat ETM+ and MODIS image. Finally, the simulated Landsat ETM+ and MODIS images were compared with the observed Landsat ETM+ and MODIS images. The results generally showed high correction coefficients (Landsat: 0.90-0.99, MODIS: 0.74-0.85) between most simulated bands and observed bands and indicated that the simulated reflectance spectrum was well simulated and reliable.

Using transfer learning to detect galaxy mergers

Science.gov (United States)

Ackermann, Sandro; Schawinksi, Kevin; Zhang, Ce; Weigel, Anna K.; Turp, M. Dennis

2018-05-01

We investigate the use of deep convolutional neural networks (deep CNNs) for automatic visual detection of galaxy mergers. Moreover, we investigate the use of transfer learning in conjunction with CNNs, by retraining networks first trained on pictures of everyday objects. We test the hypothesis that transfer learning is useful for improving classification performance for small training sets. This would make transfer learning useful for finding rare objects in astronomical imaging datasets. We find that these deep learning methods perform significantly better than current state-of-the-art merger detection methods based on nonparametric systems like CAS and GM20. Our method is end-to-end and robust to image noise and distortions; it can be applied directly without image preprocessing. We also find that transfer learning can act as a regulariser in some cases, leading to better overall classification accuracy (p = 0.02). Transfer learning on our full training set leads to a lowered error rate from 0.0381 down to 0.0321, a relative improvement of 15%. Finally, we perform a basic sanity-check by creating a merger sample with our method, and comparing with an already existing, manually created merger catalogue in terms of colour-mass distribution and stellar mass function.

Hands-free image capture, data tagging and transfer using Google Glass: a pilot study for improved wound care management.

Directory of Open Access Journals (Sweden)

Gabriel Aldaz

Full Text Available Chronic wounds, including pressure ulcers, compromise the health of 6.5 million Americans and pose an annual estimated burden of $25 billion to the U.S. health care system. When treating chronic wounds, clinicians must use meticulous documentation to determine wound severity and to monitor healing progress over time. Yet, current wound documentation practices using digital photography are often cumbersome and labor intensive. The process of transferring photos into Electronic Medical Records (EMRs requires many steps and can take several days. Newer smartphone and tablet-based solutions, such as Epic Haiku, have reduced EMR upload time. However, issues still exist involving patient positioning, image-capture technique, and patient identification. In this paper, we present the development and assessment of the SnapCap System for chronic wound photography. Through leveraging the sensor capabilities of Google Glass, SnapCap enables hands-free digital image capture, and the tagging and transfer of images to a patient's EMR. In a pilot study with wound care nurses at Stanford Hospital (n=16, we (i examined feature preferences for hands-free digital image capture and documentation, and (ii compared SnapCap to the state of the art in digital wound care photography, the Epic Haiku application. We used the Wilcoxon Signed-ranks test to evaluate differences in mean ranks between preference options. Preferred hands-free navigation features include barcode scanning for patient identification, Z(15 = -3.873, p < 0.001, r = 0.71, and double-blinking to take photographs, Z(13 = -3.606, p < 0.001, r = 0.71. In the comparison between SnapCap and Epic Haiku, the SnapCap System was preferred for sterile image-capture technique, Z(16 = -3.873, p < 0.001, r = 0.68. Responses were divided with respect to image quality and overall ease of use. The study's results have contributed to the future implementation of new features aimed at enhancing mobile hands-free digital

Hands-Free Image Capture, Data Tagging and Transfer Using Google Glass: A Pilot Study for Improved Wound Care Management

Science.gov (United States)

Aldaz, Gabriel; Shluzas, Lauren Aquino; Pickham, David; Eris, Ozgur; Sadler, Joel; Joshi, Shantanu; Leifer, Larry

2015-01-01

Chronic wounds, including pressure ulcers, compromise the health of 6.5 million Americans and pose an annual estimated burden of $25 billion to the U.S. health care system. When treating chronic wounds, clinicians must use meticulous documentation to determine wound severity and to monitor healing progress over time. Yet, current wound documentation practices using digital photography are often cumbersome and labor intensive. The process of transferring photos into Electronic Medical Records (EMRs) requires many steps and can take several days. Newer smartphone and tablet-based solutions, such as Epic Haiku, have reduced EMR upload time. However, issues still exist involving patient positioning, image-capture technique, and patient identification. In this paper, we present the development and assessment of the SnapCap System for chronic wound photography. Through leveraging the sensor capabilities of Google Glass, SnapCap enables hands-free digital image capture, and the tagging and transfer of images to a patient’s EMR. In a pilot study with wound care nurses at Stanford Hospital (n=16), we (i) examined feature preferences for hands-free digital image capture and documentation, and (ii) compared SnapCap to the state of the art in digital wound care photography, the Epic Haiku application. We used the Wilcoxon Signed-ranks test to evaluate differences in mean ranks between preference options. Preferred hands-free navigation features include barcode scanning for patient identification, Z(15) = -3.873, p < 0.001, r = 0.71, and double-blinking to take photographs, Z(13) = -3.606, p < 0.001, r = 0.71. In the comparison between SnapCap and Epic Haiku, the SnapCap System was preferred for sterile image-capture technique, Z(16) = -3.873, p < 0.001, r = 0.68. Responses were divided with respect to image quality and overall ease of use. The study’s results have contributed to the future implementation of new features aimed at enhancing mobile hands-free digital

Sketch Style Recognition, Transfer and Synthesis of Hand-Drawn Sketches

KAUST Repository

Shaheen, Sara

2017-01-01

exploits techniques from multi-disciplinary areas including geometrical modeling and image processing. It consists of two methods of transfer: stroke-style and brush-style transfer. (1) Stroke-style transfer aims to transfer the style of the input sketch

Rapid and quantitative chemical exchange saturation transfer (CEST) imaging with magnetic resonance fingerprinting (MRF).

Science.gov (United States)

Cohen, Ouri; Huang, Shuning; McMahon, Michael T; Rosen, Matthew S; Farrar, Christian T

2018-05-13

To develop a fast magnetic resonance fingerprinting (MRF) method for quantitative chemical exchange saturation transfer (CEST) imaging. We implemented a CEST-MRF method to quantify the chemical exchange rate and volume fraction of the N α -amine protons of L-arginine (L-Arg) phantoms and the amide and semi-solid exchangeable protons of in vivo rat brain tissue. L-Arg phantoms were made with different concentrations (25-100 mM) and pH (pH 4-6). The MRF acquisition schedule varied the saturation power randomly for 30 iterations (phantom: 0-6 μT; in vivo: 0-4 μT) with a total acquisition time of ≤2 min. The signal trajectories were pattern-matched to a large dictionary of signal trajectories simulated using the Bloch-McConnell equations for different combinations of exchange rate, exchangeable proton volume fraction, and water T 1 and T 2 relaxation times. The chemical exchange rates of the N α -amine protons of L-Arg were significantly (P exchange using saturation power method. Similarly, the L-Arg concentrations determined using MRF were significantly (P exchange rate was well fit (R 2  = 0.9186) by a base catalyzed exchange model. The amide proton exchange rate measured in rat brain cortex (34.8 ± 11.7 Hz) was in good agreement with that measured previously with the water exchange spectroscopy method (28.6 ± 7.4 Hz). The semi-solid proton volume fraction was elevated in white (12.2 ± 1.7%) compared to gray (8.1 ± 1.1%) matter brain regions in agreement with previous magnetization transfer studies. CEST-MRF provides a method for fast, quantitative CEST imaging. © 2018 International Society for Magnetic Resonance in Medicine.

Synthesis and systematic evaluation of dark resonance energy transfer (DRET)-based library and its application in cell imaging.

Science.gov (United States)

Su, Dongdong; Teoh, Chai Lean; Kang, Nam-Young; Yu, Xiaotong; Sahu, Srikanta; Chang, Young-Tae

2015-03-01

In this paper, we report a new strategy for constructing a dye library with large Stokes shifts. By coupling a dark donor with BODIPY acceptors of tunable high quantum yield, a novel dark resonance energy transfer (DRET)-based library, named BNM, has been synthesized. Upon excitation of the dark donor (BDN) at 490 nm, the absorbed energy is transferred to the acceptor (BDM) with high efficiency, which was tunable in a broad range from 557 nm to 716 nm, with a high quantum yield of up to 0.8. It is noteworthy to mention that the majority of the non-radiative energy loss of the donor was converted into the acceptor's fluorescence output with a minimum leak of donor emission. Fluorescence imaging tested in live cells showed that the BNM compounds are cell-permeable and can also be employed for live-cell imaging. This is a new library which can be excited through a dark donor allowing for strong fluorescence emission in a wide range of wavelengths. Thus, the BNM library is well suited for high-throughput screening or multiplex experiments in biological applications by using a single laser excitation source. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Technique for improving the quality of images from digital cameras using ink-jet printers and smoothed RGB transfer curves

Science.gov (United States)

Sampat, Nitin; Grim, John F.; O'Hara, James E.

1998-04-01

The digital camera market is growing at an explosive rate. At the same time, the quality of photographs printed on ink- jet printers continues to improve. Most of the consumer cameras are designed with the monitor as the target output device and ont the printer. When a user is printing his images from a camera, he/she needs to optimize the camera and printer combination in order to maximize image quality. We describe the details of one such method for improving image quality using a AGFA digital camera and an ink jet printer combination. Using Adobe PhotoShop, we generated optimum red, green and blue transfer curves that match the scene content to the printers output capabilities. Application of these curves to the original digital image resulted in a print with more shadow detail, no loss of highlight detail, a smoother tone scale, and more saturated colors. The image also exhibited an improved tonal scale and visually more pleasing images than those captured and printed without any 'correction'. While we report the results for one camera-printer combination we tested this technique on numbers digital cameras and printer combinations and in each case produced a better looking image. We also discuss the problems we encountered in implementing this technique.

Continuous imaging space in three-dimensional integral imaging

International Nuclear Information System (INIS)

Zhang Lei; Yang Yong; Wang Jin-Gang; Zhao Xing; Fang Zhi-Liang; Yuan Xiao-Cong

2013-01-01

We report an integral imaging method with continuous imaging space. This method simultaneously reconstructs real and virtual images in the virtual mode, with a minimum gap that separates the entire imaging space into real and virtual space. Experimental results show that the gap is reduced to 45% of that in a conventional integral imaging system with the same parameters. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Imaging using long range dipolar field effects

International Nuclear Information System (INIS)

Gutteridge, Sarah

2002-01-01

The work in this thesis has been undertaken by the author, except where indicated in reference, within the Magnetic Resonance Centre, at the University of Nottingham during the period from October 1998 to March 2001. This thesis details the different characteristics of the long range dipolar field and its application to magnetic resonance imaging. The long range dipolar field is usually neglected in nuclear magnetic resonance experiments, as molecular tumbling decouples its effect at short distances. However, in highly polarised samples residual long range components have a significant effect on the evolution of the magnetisation, giving rise to multiple spin echoes and unexpected quantum coherences. Three applications utilising these dipolar field effects are documented in this thesis. The first demonstrates the spatial sensitivity of the signal generated via dipolar field effects in structured liquid state samples. The second utilises the signal produced by the dipolar field to create proton spin density maps. These maps directly yield an absolute value for the water content of the sample that is unaffected by relaxation and any RF inhomogeneity or calibration errors in the radio frequency pulses applied. It has also been suggested that the signal generated by dipolar field effects may provide novel contrast in functional magnetic resonance imaging. In the third application, the effects of microscopic susceptibility variation on the signal are studied and the relaxation rate of the signal is compared to that of a conventional spin echo. (author)

Nanomagnetic intergrowths in Fe-Ni meteoritic metal: The potential for time-resolved records of planetesimal dynamo fields

DEFF Research Database (Denmark)

Bryson, James F.J.; Church, Nathan S.; Kasama, Takeshi

2014-01-01

been imaged using off-axis electron holography. The CZ is revealed to be a natural nanocomposite of magnetically hard islands of tetrataenite (ordered FeNi) embedded in a magnetically soft matrix of ordered Fe3Ni. In the remanent state, each tetrataenite island acts as a uniaxial single domain particle......) varies with the length scale of the matrix phase (Lm), with Hs > 1 T for Lm ∼10 nm (approaching the intrinsic switching field for isolated single domain tetrataenite) and 0.2hard tetrataenite...... field could have been present during nanostructure formation. This observation demonstrates the potential for stable chemical transformation remanent magnetisation to be encoded by the nanostructure, with variations in the proportions of the six possible magnetisation states reflecting the intensity...

Magnetization transfer imaging of periventricular white matter lesions in patients with multi-infarct dementia

International Nuclear Information System (INIS)

Hanyu, Haruo; Imon, Yukari; Asano, Tetsuichi; Iwamoto, Toshihiko; Takasaki, Masaru

1998-01-01

Using magnetization transfer (MT) imaging, we studied the underlying pathological conditions of periventricular hyperintense (PVH) white matter changes seen on T2-weighted MR images of patients with multi-infarct dementia. Twenty-two patients with multiple lacunar infarcts and PVH lesions, including 11 with dementia (diagnosed as multi-infarct dementia) and 11 without dementia, and 10 control subjects (with multiple lacunes, but no PVH lesion) were studied using the MT technique. MT ratios (MTRs) were calculated for PVH lesions (normal-appearing frontal white matter in controls) and the genu of the corpus callosum. Signal intensities on T2-weighted images in PVH lesions of patients were significantly higher than those in normal-appearing white matter of controls, while there were no significant differences in signal intensity in the genu of the corpus callosum among the dementia, non-dementia and control groups. However, MTRs in patients with PVH lesions were significantly lower than those in controls, and MTRs in demented patients were significantly lower than those in non-demented patients. Moreover, MTRs in the genu of the corpus callosum of demented patients were significantly lower than in those in non-demented patients and controls. MTRs in PVH lesions and the genu of the corpus callosum significantly correlated with Hasegawa's dementia scale score. These results suggest that there is some difference in histopathologic changes of PVH lesions between demented and non-demented patients and that the pathological substrate in the corpus callosum may play a role in inducing cognitive decline. Studies with MT imaging may allow the characterization of different pathological conditions that cannot be visualized by conventional MRI. (author)

Optimization of CMOS image sensor utilizing variable temporal multisampling partial transfer technique to achieve full-frame high dynamic range with superior low light and stop motion capability

Science.gov (United States)

Kabir, Salman; Smith, Craig; Armstrong, Frank; Barnard, Gerrit; Schneider, Alex; Guidash, Michael; Vogelsang, Thomas; Endsley, Jay

2018-03-01

Differential binary pixel technology is a threshold-based timing, readout, and image reconstruction method that utilizes the subframe partial charge transfer technique in a standard four-transistor (4T) pixel CMOS image sensor to achieve a high dynamic range video with stop motion. This technology improves low light signal-to-noise ratio (SNR) by up to 21 dB. The method is verified in silicon using a Taiwan Semiconductor Manufacturing Company's 65 nm 1.1 μm pixel technology 1 megapixel test chip array and is compared with a traditional 4 × oversampling technique using full charge transfer to show low light SNR superiority of the presented technology.

Imaging in Vivo Extracellular pH with a Single Paramagnetic Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Contrast Agent

Directory of Open Access Journals (Sweden)

Guanshu Liu

2012-01-01

Full Text Available The measurement of extracellular pH (pHe has potential utility for cancer diagnoses and for assessing the therapeutic effects of pH-dependent therapies. A single magnetic resonance imaging (MRI contrast agent that is detected through paramagnetic chemical exchange saturation transfer (PARACEST was designed to measure tumor pHe throughout the range of physiologic pH and with magnetic resonance saturation powers that are not harmful to a mouse model of cancer. The chemical characterization and modeling of the contrast agent Yb3+-1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid, 10-o-aminoanilide (Yb-DO3A-oAA suggested that the aryl amine of the agent forms an intramolecular hydrogen bond with a proximal carboxylate ligand, which was essential for generating a practical chemical exchange saturation transfer (CEST effect from an amine. A ratio of CEST effects from the aryl amine and amide was linearly correlated with pH throughout the physiologic pH range. The pH calibration was used to produce a parametric pH map of a subcutaneous flank tumor on a mouse model of MCF-7 mammary carcinoma. Although refinements in the in vivo CEST MRI methodology may improve the accuracy of pHe measurements, this study demonstrated that the PARACEST contrast agent can be used to generate parametric pH maps of in vivo tumors with saturation power levels that are not harmful to a mouse model of cancer.

Is white matter affected in adolescents with anorexia nervosa? A study using magnetization transfer imaging.

Science.gov (United States)

Akgül, Sinem; Öz, Ayşegül; Karlı-Oğuz, Kader; Kanbur, Nuray; Derman, Orhan

2016-01-01

The aim of the study was to assess potential changes in structural integrity of the brain in adolescent patients with Anorexia Nervosa (AN) using the magnetization transfer imaging technique and re-evaluating after nutritional rehabilitation was accomplished. Magnetization transfer ratio (MTR) was used for the detection and quantification of histological changes to the white matter of 9 adolescents diagnosed with AN at diagnosis and after weight gain. Using the MTR technique 6 regions were measured: the pons, left cerebellar hemisphere, amygdala, thalamus, corona radiata and white matter adjacent to the left dorsolateral prefrontal cortex. Scans from the patients with AN were also compared with scans from an age-matched subset of 9 healthy controls. Compared with control subjects, the MTR of participants with AN was no different either at the early stages of diagnosis (p=0.62) or after weight recovery (p=0.81). Similarly, comparison of MTR between patients with AN at diagnoses compared with MTR after weight recovery yielded no statistically significant difference (P=0.33). We conclude that MTR was not able to detect any neuropathological alterations in adolescent patients with AN at either diagnosis or after nutritional recovery and the achievement of weight gain.

High-resolution magnetic resonance imaging of diurnal variations in rheumatoid arthritis

International Nuclear Information System (INIS)

Nicholas, R.S.

2000-09-01

This thesis describes work that uses high-resolution magnetic resonance imaging (MRI) to give an insight into the aetiology of rheumatoid arthritis (RA) with particular reference to characterising diurnal changes in joint stiffness in the metacarpophalangeal (MCP) joints. The study was performed on a targeted 1.1 T MRI scanner using specialised sequences, including 3-dimensional gradient-echo, magnetisation transfer (MT) and multiple gradient-echo. These enabled tissue-dependent parameters such as MT ratio, effective transverse relaxation time (T 2 *) and proton density (ρ) to be made. Preliminary reproducibility studies of the MRI measurements showed that MT ratio could be measured in vivo to an accuracy of better than 8%. This variation is due to repositioning errors and physiological changes. Equivalent variations in T 2 * and p were 23% and 16% respectively; these poorer figures were contributed to errors in fitting the data to an exponential curve. An MRI study monitoring the diurnal variation of stiffness in RA demonstrated better characterisation of the disease state using MT and T 2 * maps compared to standard gradient-echo imaging. Features associated with arthritis such as bone erosions and cysts were found in the control group and an MT age dependence was measured in the soft tissue on the superior margin of the joint. This region also exhibited a diurnal variation in MT ratio for the patient group. The interaction between this region of tissue and other structures (e.g. the sheath of extensor tendon) within the joint could be a possible cause of joint stiffness. An incidental finding of this study was that Ritchie joint score also showed a diurnal variation. This study has demonstrated that MRI can be used to make reproducible measurements of the diurnal variations in RA. The indication is that the soft tissues in the superior aspect of the joint may be responsible for the symptom of joint stiffness in the MCP joints and future studies should be

Performance of asynchronous transfer mode (ATM) local area and wide area networks for medical imaging transmission in clinical environment.

Science.gov (United States)

Huang, H K; Wong, A W; Zhu, X

1997-01-01

Asynchronous transfer mode (ATM) technology emerges as a leading candidate for medical image transmission in both local area network (LAN) and wide area network (WAN) applications. This paper describes the performance of an ATM LAN and WAN network at the University of California, San Francisco. The measurements were obtained using an intensive care unit (ICU) server connecting to four image workstations (WS) at four different locations of a hospital-integrated picture archiving and communication system (HI-PACS) in a daily regular clinical environment. Four types of performance were evaluated: magnetic disk-to-disk, disk-to-redundant array of inexpensive disks (RAID), RAID-to-memory, and memory-to-memory. Results demonstrate that the transmission rate between two workstations can reach 5-6 Mbytes/s from RAID-to-memory, and 8-10 Mbytes/s from memory-to-memory. When the server has to send images to all four workstations simultaneously, the transmission rate to each WS is about 4 Mbytes/s. Both situations are adequate for radiologic image communications for picture archiving and communication systems (PACS) and teleradiology applications.

Double agents and secret agents: the emerging fields of exogenous chemical exchange saturation transfer and T2-exchange magnetic resonance imaging contrast agents for molecular imaging.

Science.gov (United States)

Daryaei, Iman; Pagel, Mark D

2015-01-01

Two relatively new types of exogenous magnetic resonance imaging contrast agents may provide greater impact for molecular imaging by providing greater specificity for detecting molecular imaging biomarkers. Exogenous chemical exchange saturation transfer (CEST) agents rely on the selective saturation of the magnetization of a proton on an agent, followed by chemical exchange of a proton from the agent to water. The selective detection of a biomarker-responsive CEST signal and an unresponsive CEST signal, followed by the ratiometric comparison of these signals, can improve biomarker specificity. We refer to this improvement as a "double-agent" approach to molecular imaging. Exogenous T 2 -exchange agents also rely on chemical exchange of protons between the agent and water, especially with an intermediate rate that lies between the slow exchange rates of CEST agents and the fast exchange rates of traditional T 1 and T 2 agents. Because of this intermediate exchange rate, these agents have been relatively unknown and have acted as "secret agents" in the contrast agent research field. This review exposes these secret agents and describes the merits of double agents through examples of exogenous agents that detect enzyme activity, nucleic acids and gene expression, metabolites, ions, redox state, temperature, and pH. Future directions are also provided for improving both types of contrast agents for improved molecular imaging and clinical translation. Therefore, this review provides an overview of two new types of exogenous contrast agents that are becoming useful tools within the armamentarium of molecular imaging.

The heat transfer mechanisms in fluidized beds; Laemmoensiirtomekanismit leijukerroksessa

Energy Technology Data Exchange (ETDEWEB)

Fogelholm, C.J.; Blomster, A.M.; Kojola, H. [Helsinki Univ. of Technology, Espoo (Finland)

1996-12-01

The goal of the research project is to improve the accuracy of the heat transfer correlation in circulating fluidized beds and to define how the heat transfer is distributed in radiation and convection in the different parts of the fluidized bed. This will be carried out by studying the behaviour and heat transfer of the fluidized bed in the boundary layer near the wall. The total and radiative heat transfer as well as the particle concentration will be measured. Based on the data a correlation will be created. Two different measurement systems are used. The particle concentration is measured by a image-analysis system. A video camera and a Super VHS recorder are used to capture live images from the bed. The images are digitized and stored on a PC. The system has been used in previous research projects at our laboratory. In earlier projects all measurements have been carried out in cold environments. In this project the system will be modified for hot environments. The radiative heat transfer is measured by a radiative heat transfer probe connected to a PC via an A/D converter. The probe consists of a heat flow detector which is isolated from the bed by a sapphire window so that only the radiative part of the heat transfer is detected. The probe will be calibrated in a black body oven so that the effect of the conduction and the sapphire window can be separated. (author)

Transfer Rate Edited experiment for the selective detection of Chemical Exchange via Saturation Transfer (TRE-CEST).

Science.gov (United States)

Friedman, Joshua I; Xia, Ding; Regatte, Ravinder R; Jerschow, Alexej

2015-07-01

Chemical Exchange Saturation Transfer (CEST) magnetic resonance experiments have become valuable tools in magnetic resonance for the detection of low concentration solutes with far greater sensitivity than direct detection methods. Accurate measures of rates of chemical exchange provided by CEST are of particular interest to biomedical imaging communities where variations in chemical exchange can be related to subtle variations in biomarker concentration, temperature and pH within tissues using MRI. Despite their name, however, traditional CEST methods are not truly selective for chemical exchange and instead detect all forms of magnetization transfer including through-space NOE. This ambiguity crowds CEST spectra and greatly complicates subsequent data analysis. We have developed a Transfer Rate Edited CEST experiment (TRE-CEST) that uses two different types of solute labeling in order to selectively amplify signals of rapidly exchanging proton species while simultaneously suppressing 'slower' NOE-dominated magnetization transfer processes. This approach is demonstrated in the context of both NMR and MRI, where it is used to detect the labile amide protons of proteins undergoing chemical exchange (at rates⩾30s(-1)) while simultaneously eliminating signals originating from slower (∼5s(-1)) NOE-mediated magnetization transfer processes. TRE-CEST greatly expands the utility of CEST experiments in complex systems, and in-vivo, in particular, where it is expected to improve the quantification of chemical exchange and magnetization transfer rates while enabling new forms of imaging contrast. Copyright © 2015 Elsevier Inc. All rights reserved.

Transfer Rate Edited experiment for the selective detection of Chemical Exchange via Saturation Transfer (TRE-CEST)

Science.gov (United States)

Friedman, Joshua I.; Xia, Ding; Regatte, Ravinder R.; Jerschow, Alexej

2015-07-01

Chemical Exchange Saturation Transfer (CEST) magnetic resonance experiments have become valuable tools in magnetic resonance for the detection of low concentration solutes with far greater sensitivity than direct detection methods. Accurate measures of rates of chemical exchange provided by CEST are of particular interest to biomedical imaging communities where variations in chemical exchange can be related to subtle variations in biomarker concentration, temperature and pH within tissues using MRI. Despite their name, however, traditional CEST methods are not truly selective for chemical exchange and instead detect all forms of magnetization transfer including through-space NOE. This ambiguity crowds CEST spectra and greatly complicates subsequent data analysis. We have developed a Transfer Rate Edited CEST experiment (TRE-CEST) that uses two different types of solute labeling in order to selectively amplify signals of rapidly exchanging proton species while simultaneously suppressing 'slower' NOE-dominated magnetization transfer processes. This approach is demonstrated in the context of both NMR and MRI, where it is used to detect the labile amide protons of proteins undergoing chemical exchange (at rates ⩾ 30 s-1) while simultaneously eliminating signals originating from slower (∼5 s-1) NOE-mediated magnetization transfer processes. TRE-CEST greatly expands the utility of CEST experiments in complex systems, and in-vivo, in particular, where it is expected to improve the quantification of chemical exchange and magnetization transfer rates while enabling new forms of imaging contrast.

Imaging quality evaluation method of pixel coupled electro-optical imaging system

Science.gov (United States)

He, Xu; Yuan, Li; Jin, Chunqi; Zhang, Xiaohui

2017-09-01

With advancements in high-resolution imaging optical fiber bundle fabrication technology, traditional photoelectric imaging system have become ;flexible; with greatly reduced volume and weight. However, traditional image quality evaluation models are limited by the coupling discrete sampling effect of fiber-optic image bundles and charge-coupled device (CCD) pixels. This limitation substantially complicates the design, optimization, assembly, and evaluation image quality of the coupled discrete sampling imaging system. Based on the transfer process of grayscale cosine distribution optical signal in the fiber-optic image bundle and CCD, a mathematical model of coupled modulation transfer function (coupled-MTF) is established. This model can be used as a basis for following studies on the convergence and periodically oscillating characteristics of the function. We also propose the concept of the average coupled-MTF, which is consistent with the definition of traditional MTF. Based on this concept, the relationships among core distance, core layer radius, and average coupled-MTF are investigated.

A new theoretical probe for the magnetic force microscope

Energy Technology Data Exchange (ETDEWEB)

Windmill, J.F.C. E-mail: jwindmill@plymouth.ac.uk; Clegg, W.W.; Jenkins, D.F.L.; Davey, P.J

2001-05-01

The magnetic force microscope (MFM) is established as a valuable tool for the analysis of magnetic structures. The standard design of MFM incorporates a silicon tip coated with a magnetic material. However, these tips are subject to several inherent problems, e.g. changing characteristics over time due to damage or magnetic hysteresis. A new theoretical electromagnetic MFM probe is introduced here. Although electromagnetic MFM has been discussed before by Zhou et al. (J. Vac. Sci. Technol. A 17 (1999) 2233), the design presented here is a different approach. Two different probe iterations and their magnetic field intensity distribution are modelled. The probe imaging capability is compared using the reciprocity principle (Wright and Hill, Appl. Phys. Lett. 68 (1996) 1726) to image the simulated force interaction between a sample and the probe fields. Thus, images of a sample's magnetic distribution are produced by the convolution of the different probe gradient field distributions and the sample magnetisation. Both perpendicular and longitudinal magnetisation patterns were simulated with the different probe iterations. This clearly showed the improvement of the second probe iteration, particularly for longitudinal patterns. The practical use of the new probe is also discussed, and future work outlined.

Applying protein-based amide proton transfer MR imaging to distinguish solitary brain metastases from glioblastoma

Energy Technology Data Exchange (ETDEWEB)

Yu, Hao; Zou, Tianyu; Wang, Xianlong; Du, Yongxing; Jiang, Chunxiu; Ma, Ling; Zhu, Jianbin; He, Wen; Rui, Qihong; Wen, Zhibo [Zhujiang Hospital, Southern Medical University, Department of Radiology, Guangzhou, Guangdong (China); Lou, Huiling [The First People' Hospital of Guangzhou, Department of Geriatrics, Guangzhou, Guangdong (China); Jiang, Shanshan [Zhujiang Hospital, Southern Medical University, Department of Radiology, Guangzhou, Guangdong (China); Johns Hopkins University School of Medicine, Division of MR Research, Department of Radiology, Baltimore, MD (United States); Huang, Zhongqing [Shantou University Medical College, Department of Medical Image Center, Yuebei People' s Hospital, Shantou, Guangdong (China); Zhou, Jianyuan [Johns Hopkins University School of Medicine, Division of MR Research, Department of Radiology, Baltimore, MD (United States)

2017-11-15

To determine the utility of amide proton transfer-weighted (APTw) MR imaging in distinguishing solitary brain metastases (SBMs) from glioblastomas (GBMs). Forty-five patients with SBMs and 43 patients with GBMs underwent conventional and APT-weighted sequences before clinical intervention. The APTw parameters and relative APTw (rAPTw) parameters in the tumour core and the peritumoral brain zone (PBZ) were obtained and compared between SBMs and GBMs. The receiver-operating characteristic (ROC) curve was used to assess the best parameter for distinguishing between the two groups. The APTw{sub max}, APTw{sub min}, APTw{sub mean}, rAPTw{sub max}, rAPTw{sub min} or rAPTw{sub mean} values in the tumour core were not significantly different between the SBM and GBM groups (P = 0.141, 0.361, 0.221, 0.305, 0.578 and 0.448, respectively). However, the APTw{sub max}, APTw{sub min}, APTw{sub mean}, rAPTw{sub max}, rAPTw{sub min} or rAPTw{sub mean} values in the PBZ were significantly lower in the SBM group than in the GBM group (P < 0.001). The APTw{sub min} values had the highest area under the ROC curve 0.905 and accuracy 85.2% in discriminating between the two neoplasms. As a noninvasive imaging method, APT-weighted MR imaging can be used to distinguish SBMs from GBMs. (orig.)

Image processing of integrated video image obtained with a charged-particle imaging video monitor system

International Nuclear Information System (INIS)

Iida, Takao; Nakajima, Takehiro

1988-01-01

A new type of charged-particle imaging video monitor system was constructed for video imaging of the distributions of alpha-emitting and low-energy beta-emitting nuclides. The system can display not only the scintillation image due to radiation on the video monitor but also the integrated video image becoming gradually clearer on another video monitor. The distortion of the image is about 5% and the spatial resolution is about 2 line pairs (lp)mm -1 . The integrated image is transferred to a personal computer and image processing is performed qualitatively and quantitatively. (author)

Quantitative MR imaging in fracture dating--Initial results.

Science.gov (United States)

Baron, Katharina; Neumayer, Bernhard; Widek, Thomas; Schick, Fritz; Scheicher, Sylvia; Hassler, Eva; Scheurer, Eva

2016-04-01

For exact age determinations of bone fractures in a forensic context (e.g. in cases of child abuse) improved knowledge of the time course of the healing process and use of non-invasive modern imaging technology is of high importance. To date, fracture dating is based on radiographic methods by determining the callus status and thereby relying on an expert's experience. As a novel approach, this study aims to investigate the applicability of magnetic resonance imaging (MRI) for bone fracture dating by systematically investigating time-resolved changes in quantitative MR characteristics after a fracture event. Prior to investigating fracture healing in children, adults were examined for this study in order to test the methodology for this application. Altogether, 31 MR examinations in 17 subjects (♀: 11 ♂: 6; median age 34 ± 15 y, scanned 1-5 times over a period of up to 200 days after the fracture event) were performed on a clinical 3T MR scanner (TimTrio, Siemens AG, Germany). All subjects were treated conservatively for a fracture in either a long bone or in the collar bone. Both, qualitative and quantitative MR measurements were performed in all subjects. MR sequences for a quantitative measurement of relaxation times T1 and T2 in the fracture gap and musculature were applied. Maps of quantitative MR parameters T1, T2, and magnetisation transfer ratio (MTR) were calculated and evaluated by investigating changes over time in the fractured area by defined ROIs. Additionally, muscle areas were examined as reference regions to validate this approach. Quantitative evaluation of 23 MR data sets (12 test subjects, ♀: 7 ♂: 5) showed an initial peak in T1 values in the fractured area (T1=1895 ± 607 ms), which decreased over time to a value of 1094 ± 182 ms (200 days after the fracture event). T2 values also peaked for early-stage fractures (T2=115 ± 80 ms) and decreased to 73 ± 33 ms within 21 days after the fracture event. After that time point, no

Light scattering reviews 8 radiative transfer and light scattering

CERN Document Server

Kokhanovsky, Alexander A

2013-01-01

Light scattering review (vol 8) is aimed at the presentation of recent advances in radiative transfer and light scattering optics. The topics to be covered include: scattering of light by irregularly shaped particles suspended in atmosphere (dust, ice crystals), light scattering by particles much larger as compared the wavelength of incident radiation, atmospheric radiative forcing, astrophysical radiative transfer, radiative transfer and optical imaging in biological media, radiative transfer of polarized light, numerical aspects of radiative transfer.

Live embryo imaging to follow cell cycle and chromosomes stability after nuclear transfer.

Science.gov (United States)

Balbach, Sebastian T; Boiani, Michele

2015-01-01

Nuclear transfer (NT) into mouse oocytes yields a transcriptionally and functionally heterogeneous population of cloned embryos. Most studies of NT embryos consider only embryos at predefined key stages (e.g., morula or blastocyst), that is, after the bulk of reprogramming has taken place. These retrospective approaches are of limited use to elucidate mechanisms of reprogramming and to predict developmental success. Observing cloned embryo development using live embryo cinematography has the potential to reveal otherwise undetectable embryo features. However, light exposure necessary for live cell cinematography is highly toxic to cloned embryos. Here we describe a protocol for combined bright-field and fluorescence live-cell imaging of histone H2b-GFP expressing mouse embryos, to record cell divisions up to the blastocyst stage. This protocol, which can be adapted to observe other reporters such as Oct4-GFP or Nanog-GFP, allowed us to quantitatively analyze cleavage kinetics of cloned embryos.

Amide Proton Transfer Magnetic Resonance Imaging of Alzheimer′s Disease at 3.0 Tesla: A Preliminary Study

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Rui Wang

2015-01-01

Full Text Available Background: Amide proton transfer (APT imaging has recently emerged as an important contrast mechanism for magnetic resonance imaging (MRI in the field of molecular and cellular imaging. The aim of this study was to evaluate the feasibility of APT imaging to detect cerebral abnormality in patients with Alzheimer′s disease (AD at 3.0 Tesla. Methods: Twenty AD patients (9 men and 11 women; age range, 67-83 years and 20 age-matched normal controls (11 men and 9 women; age range, 63-82 years underwent APT and traditional MRI examination on a 3.0 Tesla MRI system. The magnetic resonance ratio asymmetry (MTR asym values at 3.5 ppm of bilateral hippocampi (Hc, temporal white matter regions, occipital white matter regions, and cerebral peduncles were measured on oblique axial APT images. MTR asym (3.5 ppm values of the cerebral structures between AD patients and control subjects were compared with independent samples t-test. Controlling for age, partial correlation analysis was used to investigate the associations between mini-mental state examination (MMSE and the various MRI measures among AD patients. Results: Compared with normal controls, MTR asym (3.5 ppm values of bilateral Hc were significantly increased in AD patients (right 1.24% ± 0.21% vs. 0.83% ± 0.19%, left 1.18% ± 0.18% vs. 0.80%± 0.17%, t = 3.039, 3.328, P = 0.004, 0.002, respectively. MTR asym (3.5 ppm values of bilateral Hc were significantly negatively correlated with MMSE (right r = −0.559, P = 0.013; left r = −0.461, P = 0.047. Conclusions: Increased MTR asym (3.5 ppm values of bilateral Hc in AD patients and its strong correlations with MMSE suggest that APT imaging could potentially provide imaging biomarkers for the noninvasive molecular diagnosis of AD.

Noninvasive imaging of protein-protein interactions from live cells and living subjects using bioluminescence resonance energy transfer.

Science.gov (United States)

De, Abhijit; Gambhir, Sanjiv Sam

2005-12-01

This study demonstrates a significant advancement of imaging of a distance-dependent physical process, known as the bioluminescent resonance energy transfer (BRET2) signal in living subjects, by using a cooled charge-coupled device (CCD) camera. A CCD camera-based spectral imaging strategy enables simultaneous visualization and quantitation of BRET signal from live cells and cells implanted in living mice. We used the BRET2 system, which utilizes Renilla luciferase (hRluc) protein and its substrate DeepBlueC (DBC) as an energy donor and a mutant green fluorescent protein (GFP2) as the acceptor. To accomplish this objective in this proof-of-principle study, the donor and acceptor proteins were fused to FKBP12 and FRB, respectively, which are known to interact only in the presence of the small molecule mediator rapamycin. Mammalian cells expressing these fusion constructs were imaged using a cooled-CCD camera either directly from culture dishes or by implanting them into mice. By comparing the emission photon yields in the presence and absence of rapamycin, the specific BRET signal was determined. The CCD imaging approach of BRET signal is particularly appealing due to its capacity to seamlessly bridge the gap between in vitro and in vivo studies. This work validates BRET as a powerful tool for interrogating and observing protein-protein interactions directly at limited depths in living mice.

Determination of the transfer function for optical surface topography measuring instruments—a review

International Nuclear Information System (INIS)

Foreman, Matthew R; Török, Peter; Giusca, Claudiu L; Leach, Richard K; Coupland, Jeremy M

2013-01-01

A significant number of areal surface topography measuring instruments, largely based on optical techniques, are commercially available. However, implementation of optical instrumentation into production is currently difficult due to the lack of understanding of the complex interaction between the light and the component surface. Studying the optical transfer function of the instrument can help address this issue. Here a review is given of techniques for the measurement of optical transfer functions. Starting from the basis of a spatially coherent, monochromatic confocal scanning imaging system, the theory of optical transfer functions in three-dimensional (3D) imaging is presented. Further generalizations are reviewed allowing the extension of the theory to the description of conventional and interferometric 3D imaging systems. Polychromatic transfer functions and surface topography measurements are also discussed. Following presentation of theoretical results, experimental methods to measure the optical transfer function of each class of system are presented, with a focus on suitable methods for the establishment of calibration standards in 3D imaging and surface topography measurements. (topical review)

Consequences of increased use of computed tomography imaging for trauma patients in rural referring hospitals prior to transfer to a regional trauma centre.

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Berkseth, Timothy J; Mathiason, Michelle A; Jafari, Mary Ellen; Cogbill, Thomas H; Patel, Nirav Y

2014-05-01

Computed tomography (CT) plays an integral role in the evaluation and management of trauma patients. As the number of referring hospital (RH)-based CT scanners increased, so has their utilization in trauma patients before transfer. We hypothesized that this has resulted in increased time at RH, image duplication, and radiation dose. A retrospective chart review was completed for trauma activations transferred to an ACS-verified Level II Trauma Centre (TC) during two time periods: 2002-2004 (Group 1) and 2006-2008 (Group 2). 2005 data were excluded as this marked the transition period for acquisition of hospital-based CT scanners in RH. Statistical analysis included t test and χ(2) analysis. Pgroup 1 and 514 in group 2. Mean age was greater in group 2 compared to group 1 (40.3 versus 37.4, respectively; P=0.028). There were 115 patients in group 1 versus 202 patients in group 2 who underwent CT imaging at RH (Pgroup 1 had CT scans performed at the TC versus 258 patients in group 2 (Ptime at the RH was similar between the groups (117.1 and 112.3min for group 1 and 2, respectively; P=0.561). However, when comparing patients with and without a pretransfer CT at the RH, the median time at RH was 140 versus 67min, respectively (Pgroup 1 and n=42 in group 2) was not significantly different between the two time periods (P=0.392). Head CTs comprised the majority of duplicate CT imaging in both time periods (82.4% in group 1 and 90.5% in group 2). Mean total estimated radiation dose per patient was not significantly different between the two groups (group 1=8.4mSv versus group 2=7.8mSv; P=0.192). A significant increase in CT imaging at the RH prior to transfer to the TC was observed over the study periods. No associated increases in mean time at the RH, image duplication at TC, total estimated radiation dose per patient, and mortality rate were observed. Copyright © 2014 Elsevier Ltd. All rights reserved.

R1 correction in amide proton transfer imaging: indication of the influence of transcytolemmal water exchange on CEST measurements.

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Li, Hua; Li, Ke; Zhang, Xiao-Yong; Jiang, Xiaoyu; Zu, Zhongliang; Zaiss, Moritz; Gochberg, Daniel F; Gore, John C; Xu, Junzhong

2015-12-01

Amide proton transfer (APT) imaging may potentially detect mobile proteins/peptides non-invasively in vivo, but its specificity may be reduced by contamination from other confounding effects such as asymmetry of non-specific magnetization transfer (MT) effects and spin-lattice relaxation with rate R1 (=1/T1). Previously reported spillover, MT and R1 correction methods were based on a two-pool model, in which the existence of multiple water compartments with heterogeneous relaxation properties in real tissues was ignored. Such simple models may not adequately represent real tissues, and thus such corrections may be unreliable. The current study investigated the effectiveness and accuracy of correcting for R1 in APT imaging via simulations and in vivo experiments using tumor-bearing rats subjected to serial injections of Gd-DTPA that produced different tissue R1 values in regions of blood-brain-barrier breakdown. The results suggest that conventional measurements of APT contrast (such as APT* and MTRasym ) may be significantly contaminated by R1 variations, while the R1 -corrected metric AREX* was found to be relatively unaffected by R1 changes over a broad range (0.4-1 Hz). Our results confirm the importance of correcting for spin-lattice relaxation effects in quantitative APT imaging, and demonstrate the reliability of using the observed tissue R1 for corrections to obtain more specific and accurate measurements of APT contrast in vivo. The results also indicate that, due to relatively fast transcytolemmal water exchange, the influence of intra- and extracellular water compartments on CEST measurements with seconds long saturation time may be ignored in tumors. Copyright © 2015 John Wiley & Sons, Ltd.

Grading diffuse gliomas without intense contrast enhancement by amide proton transfer MR imaging: comparisons with diffusion- and perfusion-weighted imaging

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Togao, Osamu; Hiwatashi, Akio; Yamashita, Koji; Kikuchi, Kazufumi; Honda, Hiroshi [Kyushu University, Department of Clinical Radiology, Graduate School of Medical Sciences, Fukuoka (Japan); Keupp, Jochen [Philips Research, Hamburg (Germany); Yoshimoto, Koji; Kuga, Daisuke; Iihara, Koji [Kyushu University, Department of Neurosurgery, Graduate School of Medical Sciences, Fukuoka (Japan); Yoneyama, Masami [Philips Electronics Japan, Tokyo (Japan); Suzuki, Satoshi O.; Iwaki, Toru [Kyushu University, Department of Neuropathology, Graduate School of Medical Sciences, Fukuoka (Japan); Takahashi, Masaya [Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX (United States)

2017-02-15

To investigate whether amide proton transfer (APT) MR imaging can differentiate high-grade gliomas (HGGs) from low-grade gliomas (LGGs) among gliomas without intense contrast enhancement (CE). This retrospective study evaluated 34 patients (22 males, 12 females; age 36.0 ± 11.3 years) including 20 with LGGs and 14 with HGGs, all scanned on a 3T MR scanner. Only tumours without intense CE were included. Two neuroradiologists independently performed histogram analyses to measure the 90th-percentile (APT{sub 90}) and mean (APT{sub mean}) of the tumours' APT signals. The apparent diffusion coefficient (ADC) and relative cerebral blood volume (rCBV) were also measured. The parameters were compared between the groups with Student's t-test. Diagnostic performance was evaluated with receiver operating characteristic (ROC) analysis. The APT{sub 90} (2.80 ± 0.59 % in LGGs, 3.72 ± 0.89 in HGGs, P = 0.001) and APT{sub mean} (1.87 ± 0.49 % in LGGs, 2.70 ± 0.58 in HGGs, P = 0.0001) were significantly larger in the HGGs compared to the LGGs. The ADC and rCBV values were not significantly different between the groups. Both the APT{sub 90} and APT{sub mean} showed medium diagnostic performance in this discrimination. APT imaging is useful in discriminating HGGs from LGGs among diffuse gliomas without intense CE. (orig.)

Impact of ultrasound video transfer on the practice of ultrasound

Science.gov (United States)

Duerinckx, Andre J.; Hayrapetian, Alek S.; Grant, Edward G.; Valentino, Daniel J.; Rahbar, Darius; Kiszonas, Mike; Franco, Ricky; Melany, Michelle; Narin, Sherelle L.; Ragavendra, Nagesh

1996-05-01

Sonography can be highly dependent on real-time imaging and as such is highly physician intensive. Such situations arise mostly during complicated ultrasound radiology studies or echocardiology examinations. Under those circumstances it would be of benefit to transmit real-time images beyond the immediate area of the ultrasound laboratory when a physician is not on location. We undertook this study to determine if both static and dynamic image transfer to remote locations might be accomplished using an ultrafast ATM network and PACS. Image management of the local image files was performed by a commercial PACS from AGFA corporation. The local network was Ethernet based, and the global network was based on Asynchronous Transfer Mode (ATM, rates up to 100 Mbits/sec). Real-time image transfer involved two teaching hospitals, one of which had 2 separate ultrasound facilities. Radiologists consulted with technologists via telephone while the examinations were being performed. The applications of ATM network providing real time video for ultrasound imaging in a clinical environment and its potential impact on health delivery and clinical teaching. This technology increased technologist and physician productivity due to the elimination of commute time for physicians and waiting time for technologists and patients. Physician confidence in diagnosis increased compared to reviewing static images alone. This system provided instant access for radiologists to real-time scans from remote sites. Image quality and frame rate were equivalent to the original. The system increased productivity by allowing physicians to monitor studies at multiple sites simultaneously.

Applying Amide Proton Transfer MR Imaging to Hybrid Brain PET/MR: Concordance with Gadolinium Enhancement and Added Value to [18F]FDG PET.

Science.gov (United States)

Sun, Hongzan; Xin, Jun; Zhou, Jinyuan; Lu, Zaiming; Guo, Qiyong

2018-06-01

The purpose of this study is to evaluate the diagnostic concordance and metric correlations of amide proton transfer (APT) imaging with gadolinium-enhanced magnetic resonance imaging (MRI) and 2-deoxy-2-[ 18 F-]fluoro-D-glucose ([ 18 F]FDG) positron emission tomography (PET), using hybrid brain PET/MRI. Twenty-one subjects underwent brain gadolinium-enhanced [ 18 F]FDG PET/MRI prospectively. Imaging accuracy was compared between unenhanced MRI, MRI with enhancement, APT-weighted (APTW) images, and PET based on six diagnostic criteria. Among tumors, the McNemar test was further used for concordance assessment between gadolinium-enhanced imaging, APT imaging, and [ 18 F]FDG PET. As well, the relation of metrics between APT imaging and PET was analyzed by the Pearson correlation analysis. APT imaging and gadolinium-enhanced MRI showed superior and similar diagnostic accuracy. APTW signal intensity and gadolinium enhancement were concordant in 19 tumors (100 %), while high [ 18 F]FDG avidity was shown in only 12 (63.2 %). For the metrics from APT imaging and PET, there was significant correlation for 13 hypermetabolic tumors (P PET in the evaluation of tumor metabolic activity during brain PET/MR studies.

Depth to Curie temperature across the central Red Sea from magnetic data using the de-fractal method

Science.gov (United States)

Salem, Ahmed; Green, Chris; Ravat, Dhananjay; Singh, Kumar Hemant; East, Paul; Fairhead, J. Derek; Mogren, Saad; Biegert, Ed

2014-06-01

The central Red Sea rift is considered to be an embryonic ocean. It is characterised by high heat flow, with more than 90% of the heat flow measurements exceeding the world mean and high values extending to the coasts - providing good prospects for geothermal energy resources. In this study, we aim to map the depth to the Curie isotherm (580 °C) in the central Red Sea based on magnetic data. A modified spectral analysis technique, the “de-fractal spectral depth method” is developed and used to estimate the top and bottom boundaries of the magnetised layer. We use a mathematical relationship between the observed power spectrum due to fractal magnetisation and an equivalent random magnetisation power spectrum. The de-fractal approach removes the effect of fractal magnetisation from the observed power spectrum and estimates the parameters of depth to top and depth to bottom of the magnetised layer using iterative forward modelling of the power spectrum. We applied the de-fractal approach to 12 windows of magnetic data along a profile across the central Red Sea from onshore Sudan to onshore Saudi Arabia. The results indicate variable magnetic bottom depths ranging from 8.4 km in the rift axis to about 18.9 km in the marginal areas. Comparison of these depths with published Moho depths, based on seismic refraction constrained 3D inversion of gravity data, showed that the magnetic bottom in the rift area corresponds closely to the Moho, whereas in the margins it is considerably shallower than the Moho. Forward modelling of heat flow data suggests that depth to the Curie isotherm in the centre of the rift is also close to the Moho depth. Thus Curie isotherm depths estimated from magnetic data may well be imaging the depth to the Curie temperature along the whole profile. Geotherms constrained by the interpreted Curie isotherm depths have subsequently been calculated at three points across the rift - indicating the variation in the likely temperature profile with

Three-Dimensional Reconstruction of Nuclear Envelope Architecture Using Dual-Color Metal-Induced Energy Transfer Imaging.

Science.gov (United States)

Chizhik, Anna M; Ruhlandt, Daja; Pfaff, Janine; Karedla, Narain; Chizhik, Alexey I; Gregor, Ingo; Kehlenbach, Ralph H; Enderlein, Jörg

2017-12-26

The nuclear envelope, comprising the inner and the outer nuclear membrane, separates the nucleus from the cytoplasm and plays a key role in cellular functions. Nuclear pore complexes (NPCs), which are embedded in the nuclear envelope, control transport of macromolecules between the two compartments. Here, using dual-color metal-induced energy transfer (MIET), we determine the axial distance between Lap2β and Nup358 as markers for the inner nuclear membrane and the cytoplasmic side of the NPC, respectively. Using MIET imaging, we reconstruct the 3D profile of the nuclear envelope over the whole basal area, with an axial resolution of a few nanometers. This result demonstrates that optical microscopy can achieve nanometer axial resolution in biological samples and without recourse to complex interferometric approaches.

An investigation of heat transfer between a microcantilever and a substrate for improved thermal topography imaging

International Nuclear Information System (INIS)

Somnath, Suhas; King, William P

2014-01-01

This paper reports the numerical and experimental investigation of heat transfer from a heated microcantilever to a substrate and uses the resulting insights to improve thermal topography imaging. The cantilever sensitivity, defined as change in thermal signal due to changes in the topography height, is relatively constant for feature heights in the range 100–350 nm. Since the cantilever-substrate heat transfer is governed by thermal conduction through the air, the cantilever sensitivity is nearly constant across substrates of varying thermal conductivity. Surface features with lateral size larger than 2.5 μm can induce artifacts in the cantilever signal resulting in measurement errors as large as 28%. These artifacts arise from thermal conduction from the cantilever in the lateral direction, parallel to the surface. We show how these artifacts can be removed by accounting for this lateral conduction and removing it from the thermal signal. This technique reduces the measurement error by as much as 26%, can be applied to arbitrary substrate topographies, and can be scaled to arrays of heated cantilevers. These results could lead to improvements in nanometer-scale thermal measurements including scanning thermal microscopy and tip-based nanofabrication. (paper)

Processing computed tomography images by using personal computer

International Nuclear Information System (INIS)

Seto, Kazuhiko; Fujishiro, Kazuo; Seki, Hirofumi; Yamamoto, Tetsuo.

1994-01-01

Processing of CT images was attempted by using a popular personal computer. The program for image-processing was made with C compiler. The original images, acquired with CT scanner (TCT-60A, Toshiba), were transferred to the computer by 8-inch flexible diskette. Many fundamental image-processing, such as displaying image to the monitor, calculating CT value and drawing the profile curve. The result showed that a popular personal computer had ability to process CT images. It seemed that 8-inch flexible diskette was still useful medium of transferring image data. (author)

B1 -sensitivity analysis of quantitative magnetization transfer imaging.

Science.gov (United States)

Boudreau, Mathieu; Stikov, Nikola; Pike, G Bruce

2018-01-01

To evaluate the sensitivity of quantitative magnetization transfer (qMT) fitted parameters to B 1 inaccuracies, focusing on the difference between two categories of T 1 mapping techniques: B 1 -independent and B 1 -dependent. The B 1 -sensitivity of qMT was investigated and compared using two T 1 measurement methods: inversion recovery (IR) (B 1 -independent) and variable flip angle (VFA), B 1 -dependent). The study was separated into four stages: 1) numerical simulations, 2) sensitivity analysis of the Z-spectra, 3) healthy subjects at 3T, and 4) comparison using three different B 1 imaging techniques. For typical B 1 variations in the brain at 3T (±30%), the simulations resulted in errors of the pool-size ratio (F) ranging from -3% to 7% for VFA, and -40% to > 100% for IR, agreeing with the Z-spectra sensitivity analysis. In healthy subjects, pooled whole-brain Pearson correlation coefficients for F (comparing measured double angle and nominal flip angle B 1 maps) were ρ = 0.97/0.81 for VFA/IR. This work describes the B 1 -sensitivity characteristics of qMT, demonstrating that it varies substantially on the B 1 -dependency of the T 1 mapping method. Particularly, the pool-size ratio is more robust against B 1 inaccuracies if VFA T 1 mapping is used, so much so that B 1 mapping could be omitted without substantially biasing F. Magn Reson Med 79:276-285, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Thermal effects on the cyclotron line formation process in X-ray pulsars

International Nuclear Information System (INIS)

Kirk, J.G.; Meszaros, P.

1980-01-01

We derive expressions for the scattering and absorption cross sections in a hot plasma including the effects of vacuum polarisation. These expressions are then used in a radiative transfer calculation for frequencies in the neighbourhood of the cyclotron resonance using a simplified model atmosphere for accreting magnetised X-ray pulsars. Cyclotron emission and absorption line model fits are discussed, the conclusion being that an emission line interpretation appears at this stage more likely. (orig.)

Transfer learning for bimodal biometrics recognition

Science.gov (United States)

Dan, Zhiping; Sun, Shuifa; Chen, Yanfei; Gan, Haitao

2013-10-01

Biometrics recognition aims to identify and predict new personal identities based on their existing knowledge. As the use of multiple biometric traits of the individual may enables more information to be used for recognition, it has been proved that multi-biometrics can produce higher accuracy than single biometrics. However, a common problem with traditional machine learning is that the training and test data should be in the same feature space, and have the same underlying distribution. If the distributions and features are different between training and future data, the model performance often drops. In this paper, we propose a transfer learning method for face recognition on bimodal biometrics. The training and test samples of bimodal biometric images are composed of the visible light face images and the infrared face images. Our algorithm transfers the knowledge across feature spaces, relaxing the assumption of same feature space as well as same underlying distribution by automatically learning a mapping between two different but somewhat similar face images. According to the experiments in the face images, the results show that the accuracy of face recognition has been greatly improved by the proposed method compared with the other previous methods. It demonstrates the effectiveness and robustness of our method.

Cost Savings Associated with the Adoption of a Cloud Computing Data Transfer System for Trauma Patients.

Science.gov (United States)

Feeney, James M; Montgomery, Stephanie C; Wolf, Laura; Jayaraman, Vijay; Twohig, Michael

2016-09-01

Among transferred trauma patients, challenges with the transfer of radiographic studies include problems loading or viewing the studies at the receiving hospitals, and problems manipulating, reconstructing, or evalu- ating the transferred images. Cloud-based image transfer systems may address some ofthese problems. We reviewed the charts of patients trans- ferred during one year surrounding the adoption of a cloud computing data transfer system. We compared the rates of repeat imaging before (precloud) and af- ter (postcloud) the adoption of the cloud-based data transfer system. During the precloud period, 28 out of 100 patients required 90 repeat studies. With the cloud computing transfer system in place, three out of 134 patients required seven repeat films. There was a statistically significant decrease in the proportion of patients requiring repeat films (28% to 2.2%, P < .0001). Based on an annualized volume of 200 trauma patient transfers, the cost savings estimated using three methods of cost analysis, is between $30,272 and $192,453.

Thermal transfer recording media

Science.gov (United States)

Takei, T.; Taniguchi, M.; Fukushima, H.; Yamaguchi, Y.; Shinozuka, M.; Seikohsha, K. K. Suwa

1988-08-01

The recording media consist of more than or one coloring layer and a layer containing a flame retardant to ensure noncombustibility and good thermal transfer. Thus, a PET film was coated on a side with a compound containing Vylon 290 (polyester resin), AFR-1021 (decabromodiphenyl oxide) 8 and Polysafe 60 (Sb oxide), and coated on the other side with a compound containing carnauba wax, HNP-9 (paraffin wax), EV-410 (ethylene-vinyl acetate copolymer), and Cu phthalocyanine to give a thermal transfer recording medium which showed good noncombustibility and antiblocking properties, and provided high quality images.

Telecytology: Is it possible with smartphone images?

Science.gov (United States)

Sahin, Davut; Hacisalihoglu, Uguray Payam; Kirimlioglu, Saime Hale

2018-01-01

This study aimed to discuss smartphone usage in telecytology and determine intraobserver concordance between microscopic cytopathological diagnoses and diagnoses derived via static smartphone images. The study was conducted with 172 cytologic material. A pathologist captured static images of the cytology slides from the ocular lens of a microscope using a smartphone. The images were transferred via WhatsApp® to a cytopathologist working in another center who made all the microscopic cytopathological diagnoses 5-27 months ago. The cytopathologist diagnosed images on a smartphone without knowledge of their previous microscopic diagnoses. The Kappa agreement between microscopic cytopathological diagnoses and smartphone image diagnoses was determined. The average image capturing, transfer, and remote cytopathological diagnostic time for one case was 6.20 minutes. The percentage of cases whose microscopic and smartphone image diagnoses were concordant was 84.30%, and the percentage of those whose diagnoses were discordant was 15.69%. The highest Kappa agreement was observed in endoscopic ultrasound-guided fine needle aspiration (1.000), and the lowest agreement was observed in urine cytology (0.665). Patient management changed with smart phone image diagnoses at 11.04%. This study showed that easy, fast, and high-quality image capturing and transfer is possible from cytology slides using smartphones. The intraobserver Kappa agreement between the microscopic cytopathological diagnoses and remote smartphone image diagnoses was high. It was found that remote diagnosis due to difficulties in telecytology might change patient management. The developments in the smartphone camera technology and transfer software make them efficient telepathology and telecytology tools. © 2017 Wiley Periodicals, Inc.

MRI techniques and cognitive impairment in the early phase of relapsing-remitting multiple sclerosis

International Nuclear Information System (INIS)

Zivadinov, R.; De Masi, R.; Nasuelli, D.; Monti Bragadin, L.; Cazzato, G.; Zorzon, M.; Ukmar, M.; Pozzi-Mucelli, R.S.; Grop, A.

2001-01-01

Correlation studies between various conventional and non-conventional MRI parameters and cognitive impairment in the early stages of multiple sclerosis (MS) are lacking, although it is known that a number of patients with early MS have mild cognitive impairment. Our aim was to explore whether this cognitive impairment is dependent on the extent and severity of the burden of disease, diffuse microscopic brain damage or both. We studied 63 patients with clinically definite relapsing-remitting (RR) MS, duration of disease 1-10 years and Expanded disability status scale scores ≤ 5.0. Mean age was 35.4 years, mean duration of disease 5.8 years and median EDSS score 1.5. Neuropsychological performance, psychological function, neurological impairment and disability were assessed. The patients also underwent MRI, including magnetisation-transfer (MT) studies. We quantified the lesion load on T2- and T1-weighted images, the magnetisation transfer ratio (MTR) of normal-appearing brain tissue (NABT) and the brain parenchymal fraction (BPF). No significant difference was found between lesion loads in patients with and without cognitive impairment. In 15 patients (23.8 %) with overall cognitive impairment, median BPF and average NABT MTR were significantly lower than those in patients without cognitive impairment (0.868 vs 0.892, P = 0.02 and 28.3 vs 29.7 P = 0.046, respectively). Multiple regression analysis models demonstrated that the only variables independently correlated with cognitive impairment were: BPF (R = 0.89, P = 0.001) and average NABT MTR (R = 0.76, P = 0.012). Our findings support the hypothesis that, cognitive decline in patients with MS, a low disability score and short duration of disease is directly associated with the extent and severity of diffuse brain damage. The loss of brain parenchyma did not correlate with the severity of microscopic damage in the NABT, indicating that the two processes could be distinct in the early stages of the disease. (orig.)

Image formation in diagnostic X-ray equipment

International Nuclear Information System (INIS)

Boer, J.A. den.

1983-01-01

This thesis deals with a physical description of the image formation in static radiographic shadow image X-ray equipment and an analysis of the optimization of such systems. For the latter criteria have been developed that take into account all relevant physical phenomena that relate to properties of the image and the radiation exposure of the patient. The discussion of image formation results in a number of relations between the X-ray system parameters on the one hand and properties of the X-ray image on the other. The three principal aspects considered are energy transfer, modulation transfer and noise. (Auth./C.F.)

Charge density of 58Ni, by scattering of electrons at high moment transfer

International Nuclear Information System (INIS)

Turck, Sylvaine

1976-01-01

Due to the unique electromagnetic interaction involved, electron elastic scattering allows a nuclear structure to be tested through nucleus magnetisation and charge distribution. In a first part, this research thesis reports experiments performed on the Saclay Linear Accelerator (ALS) with the 58 Ni nucleus, a well closed magic nucleus which allows a qualitative comparison between experiments and Hartree-Fock calculations to be performed. The author presents the experimental set-up, describes data acquisition, data reduction and corrections. The second part proposes a theoretical introduction to electron scattering, discusses the analysis without model, and theoretical predictions of charge density

Imaging after vascular gene therapy

International Nuclear Information System (INIS)

Manninen, Hannu I.; Yang, Xiaoming

2005-01-01

Targets for cardiovascular gene therapy currently include limiting restenosis after balloon angioplasty and stent placement, inhibiting vein bypass graft intimal hyperplasia/stenosis, therapeutic angiogenesis for cardiac and lower-limb ischemia, and prevention of thrombus formation. While catheter angiography is still standard method to follow-up vascular gene transfer, other modern imaging techniques, especially intravascular ultrasound (IVUS), magnetic resonance (MR), and positron emission tomography (PET) imaging provide complementary information about the therapeutic effect of vascular gene transfer in humans. Although molecular imaging of therapeutic gene expression in the vasculatures is still in its technical development phase, it has already offered basic medical science an extremely useful in vivo evaluation tool for non- or minimally invasive imaging of vascular gene therapy

Heat-Assisted Multiferroic Solid-State Memory.

Science.gov (United States)

Lepadatu, Serban; Vopson, Melvin M

2017-08-25

A heat-assisted multiferroic solid-state memory design is proposed and analysed, based on a PbNbZrSnTiO₃ antiferroelectric layer and Ni 81 Fe 19 magnetic free layer. Information is stored as magnetisation direction in the free layer of a magnetic tunnel junction element. The bit writing process is contactless and relies on triggering thermally activated magnetisation switching of the free layer towards a strain-induced anisotropy easy axis. A stress is generated using the antiferroelectric layer by voltage-induced antiferroelectric to ferroelectric phase change, and this is transmitted to the magnetic free layer by strain-mediated coupling. The thermally activated strain-induced magnetisation switching is analysed here using a three-dimensional, temperature-dependent magnetisation dynamics model, based on simultaneous evaluation of the stochastic Landau-Lifshitz-Bloch equation and heat flow equation, together with stochastic thermal fields and magnetoelastic contributions. The magnetisation switching probability is calculated as a function of stress magnitude and maximum heat pulse temperature. An operating region is identified, where magnetisation switching always occurs, with stress values ranging from 80 to 180 MPa, and maximum temperatures normalised to the Curie temperature ranging from 0.65 to 0.99.

An excited-state intramolecular photon transfer fluorescence probe for localizable live cell imaging of cysteine

Science.gov (United States)

Liu, Wei; Chen, Wen; Liu, Si-Jia; Jiang, Jian-Hui

2017-03-01

Small molecule probes suitable for selective and specific fluorescence imaging of some important but low-concentration intracellular reactive sulfur species such as cysteine (Cys) pose a challenge in chemical biology. We present a readily available, fast-response fluorescence probe CHCQ-Ac, with 2-(5‧-chloro-2-hydroxyl-phenyl)-6-chloro-4(3 H)-quinazolinone (CHCQ) as the fluorophore and acrylate group as the functional moiety, that enables high-selectivity and high-sensitivity for detecting Cys in both solution and biological system. After specifically reacted with Cys, the probe undergoes a seven-membered intramolecular cyclization and released the fluorophore CHCQ with excited-state intramolecular photon transfer effect. A highly fluorescent, insoluble aggregate was then formed to facilitate high-sensitivity and high-resolution imaging. The results showed that probe CHCQ-Ac affords a remarkably large Stokes shift and can detect Cys under physiological pH condition with no interference from other analytes. Moreover, this probe was proved to have excellent chemical stability, low cytotoxicity and good cell permeability. Our design of this probe provides a novel potential tool to visualize and localize cysteine in bioimaging of live cells that would greatly help to explore various Cys-related physiological and pathological cellular processes in cell biology and diagnostics.

Multimodality imaging: transfer and fusion of SPECT and MRI data

International Nuclear Information System (INIS)

Knesaurek, K.

1994-01-01

Image fusion is a technique which offers the best of both worlds. It unites the two basic types of medical images: functional body images(PET or SPECT scans), which provide physiological information, and structural images (CT or MRI), which provide an anatomic map of the body. Control-point based registration technique was developed and used. Tc-99m point sources were used as external markers in SPECT studies while, for MRI and CT imaging only anatomic landmarks were used as a control points. The MRI images were acquired on GE Signa 1.2 system and CT data on a GE 9800 scanner. SPECT studies were performed 1h after intravenous injection of the 740 MBq of the Tc-99m-HMPAO on the triple-headed TRIONIX gamma camera. B-spline and bilinear interpolation were used for the rotation, scaling and translation of the images. In the process of creation of a single composite image, in order to retain information from the individual images, MRI (or CT) image was scaled to one color range and a SPECT image to another. In some situations the MRI image was kept black-and-white while the SPECT image was pasted on top of it in 'opaque' mode. Most errors which propagate through the matching process are due to sample size, imperfection of the acquisition system, noise and interpolations used. Accuracy of the registration was investigated by SPECT-CT study performed on a phantom study. The results has shown that accuracy of the matching process is better, or at worse, equal to 2 mm. (author)

CHARACTERIZING TRANSFER OF SURFACE RESIDUES TO SKIN USING A VIDEO-FLUORESCENT IMAGING TECHNIQUE

Science.gov (United States)

Surface-to-skin transfer of contaminants is a complex process. For children's residential exposure, transfer of chemicals from contaminated surfaces such as floors and furniture is potentially significant. Once on the skin, residues and contaminated particles can be transferred b...

Exchange rates of creatine kinase metabolites: feasibility of imaging creatine by chemical exchange saturation transfer MRI.

Science.gov (United States)

Haris, Mohammad; Nanga, Ravi Prakash Reddy; Singh, Anup; Cai, Kejia; Kogan, Feliks; Hariharan, Hari; Reddy, Ravinder

2012-11-01

Creatine (Cr), phosphocreatine (PCr) and adenosine-5-triphosphate (ATP) are major metabolites of the enzyme creatine kinase (CK). The exchange rate of amine protons of CK metabolites at physiological conditions has been limited. In the current study, the exchange rate and logarithmic dissociation constant (pKa) of amine protons of CK metabolites were calculated. Further, the chemical exchange saturation transfer effect (CEST) of amine protons of CK metabolites with bulk water was explored. At physiological temperature and pH, the exchange rate of amine protons in Cr was found to be 7-8 times higher than PCr and ATP. A higher exchange rate in Cr was associated with lower pKa value, suggesting faster dissociation of its amine protons compared to PCr and ATP. CEST MR imaging of these metabolites in vitro in phantoms displayed predominant CEST contrast from Cr and negligible contribution from PCr and ATP with the saturation pulse parameters used in the current study. These results provide a new method to perform high-resolution proton imaging of Cr without contamination from PCr. Potential applications of these finding are discussed. Copyright © 2012 John Wiley & Sons, Ltd.

3D Micro-topography of Transferred Laboratory and Natural Ice Crystal Surfaces Imaged by Cryo and Environmental Scanning Electron Microscopy

Science.gov (United States)

Magee, N. B.; Boaggio, K.; Bancroft, L.; Bandamede, M.

2015-12-01

Recent work has highlighted micro-scale roughness on the surfaces of ice crystals grown and imaged in-situ within the chambers of environmental scanning electron microscopes (ESEM). These observations appear to align with theoretical and satellite observations that suggest a prevalence of rough ice in cirrus clouds. However, the atmospheric application of the lab observations are indeterminate because the observations have been based only on crystals grown on substrates and in pure-water vapor environments. In this work, we present details and results from the development of a transfer technique which allows natural and lab-grown ice and snow crystals to be captured, preserved, and transferred into the ESEM for 3D imaging. Ice crystals were gathered from 1) natural snow, 2) a balloon-borne cirrus particle capture device, and 3) lab-grown ice crystals from a diffusion chamber. Ice crystals were captured in a pre-conditioned small-volume (~1 cm3) cryo-containment cell. The cell was then sealed closed and transferred to a specially-designed cryogenic dewer (filled with liquid nitrogen or crushed dry ice) for transport to a new Hitachi Field Emission, Variable Pressure SEM (SU-5000). The cryo-cell was then removed from the dewer and quickly placed onto the pre-conditioned cryo transfer stage attached to the ESEM (Quorum 3010T). Quantitative 3D topographical digital elevation models of ice surfaces are reported from SEM for the first time, including a variety of objective measures of statistical surface roughness. The surfaces of the transported crystals clearly exhibit signatures of mesoscopic roughening that are similar to examples of roughness seen in ESEM-grown crystals. For most transported crystals, the habits and crystal edges are more intricate that those observed for ice grown directly on substrates within the ESEM chamber. Portions of some crystals do appear smooth even at magnification greater than 1000x, a rare observation in our ESEM-grown crystals. The

The heat transfer mechanisms in fluidized beds; Laemmoensiirtomekanismit leijukerroksessa

Energy Technology Data Exchange (ETDEWEB)

Fogelholm, C.J.; Blomster, A.M.; Kojola, H. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Energy Technology and Environmental Protection

1997-10-01

The goal of the research project is to improve the accuracy of the heat transfer correlation in circulating fluidized beds and to define how the heat transfer is distributed in radiation and convection in the different parts of the fluidized bed. This will be carried out by studying the behaviour and the heat transfer of the fluidized bed in the boundary layer near the wall. During the project the concentration and the velocity of the sand particles are measured. The particle concentration and the particle velocity are measured by an image analysis system. A video camera and a Super VHS recorder are used to capture live images from the bed. The images are digitized and stored on a PC. The measured particle concentration was at highest slightly over 20 % on the straight wall. As expected, the velocity of the fluidizing gas had the most important role on the particle concentration. The experimental studies of the particle velocity were started last autumn 1996. The velocities of the particles were measured by using a multiple exposure technique. Afterwards the images captured were analyzed by performing a Fourier transform analysis. So far the results have been encouraging and the analyzing work will be ended this spring. (orig.)

Simulation and measurement of total ionizing dose radiation induced image lag increase in pinned photodiode CMOS image sensors

Energy Technology Data Exchange (ETDEWEB)

Liu, Jing [School of Materials Science and Engineering, Xiangtan University, Hunan (China); State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China); Chen, Wei, E-mail: chenwei@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China); Wang, Zujun, E-mail: wangzujun@nint.ac.cn [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China); Xue, Yuanyuan; Yao, Zhibin; He, Baoping; Ma, Wuying; Jin, Junshan; Sheng, Jiangkun; Dong, Guantao [State Key Laboratory of Intense Pulsed Irradiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an (China)

2017-06-01

This paper presents an investigation of total ionizing dose (TID) induced image lag sources in pinned photodiodes (PPD) CMOS image sensors based on radiation experiments and TCAD simulation. The radiation experiments have been carried out at the Cobalt −60 gamma-ray source. The experimental results show the image lag degradation is more and more serious with increasing TID. Combining with the TCAD simulation results, we can confirm that the junction of PPD and transfer gate (TG) is an important region forming image lag during irradiation. These simulations demonstrate that TID can generate a potential pocket leading to incomplete transfer.

DEVELOPMENT OF EVALUATION OF A QUANTITATIVE VIDEO-FLUORESCENCE IMAGING SYSTEM AND FLUORESCENT TRACER FOR MEASURING TRANSFER OF PESTICIDE RESIDUES FROM SURFACES TO HANDS WITH REPEATED CONTACTS

Science.gov (United States)

A video imaging system and the associated quantification methods have been developed for measurement of the transfers of a fluorescent tracer from surfaces to hands. The highly fluorescent compound riboflavin (Vitamin B2), which is also water soluble and non-toxic, was chosen as...

Delineation of cortical pathology in multiple sclerosis using multi-surface magnetization transfer ratio imaging

Directory of Open Access Journals (Sweden)

David A. Rudko

2016-01-01

Full Text Available The purpose of our study was to evaluate the utility of measurements of cortical surface magnetization transfer ratio (csMTR on the inner, mid and outer cortical boundaries as clinically accessible biomarkers of cortical gray matter pathology in multiple sclerosis (MS. Twenty-five MS patients and 12 matched controls were recruited from the MS Clinic of the Montreal Neurological Institute. Anatomical and magnetization transfer ratio (MTR images were acquired using 3 Tesla MRI at baseline and two-year time-points. MTR maps were smoothed along meshes representing the inner, mid and outer neocortical boundaries. To evaluate csMTR reductions suggestive of sub-pial demyelination in MS patients, a mixed model analysis was carried out at both the individual vertex level and in anatomically parcellated brain regions. Our results demonstrate that focal areas of csMTR reduction are most prevalent along the outer cortical surface in the superior temporal and posterior cingulate cortices, as well as in the cuneus and precentral gyrus. Additionally, age regression analysis identified that reductions of csMTR in MS patients increase with age but appear to hit a plateau in the outer caudal anterior cingulate, as well as in the precentral and postcentral cortex. After correction for the naturally occurring gradient in cortical MTR, the difference in csMTR between the inner and outer cortex in focal areas in the brains of MS patients correlated with clinical disability. Overall, our findings support multi-surface analysis of csMTR as a sensitive marker of cortical sub-pial abnormality indicative of demyelination in MS patients.

Extraction of Built-Up Areas Using Convolutional Neural Networks and Transfer Learning from SENTINEL-2 Satellite Images

Science.gov (United States)

Bramhe, V. S.; Ghosh, S. K.; Garg, P. K.

2018-04-01

With rapid globalization, the extent of built-up areas is continuously increasing. Extraction of features for classifying built-up areas that are more robust and abstract is a leading research topic from past many years. Although, various studies have been carried out where spatial information along with spectral features has been utilized to enhance the accuracy of classification. Still, these feature extraction techniques require a large number of user-specific parameters and generally application specific. On the other hand, recently introduced Deep Learning (DL) techniques requires less number of parameters to represent more abstract aspects of the data without any manual effort. Since, it is difficult to acquire high-resolution datasets for applications that require large scale monitoring of areas. Therefore, in this study Sentinel-2 image has been used for built-up areas extraction. In this work, pre-trained Convolutional Neural Networks (ConvNets) i.e. Inception v3 and VGGNet are employed for transfer learning. Since these networks are trained on generic images of ImageNet dataset which are having very different characteristics from satellite images. Therefore, weights of networks are fine-tuned using data derived from Sentinel-2 images. To compare the accuracies with existing shallow networks, two state of art classifiers i.e. Gaussian Support Vector Machine (SVM) and Back-Propagation Neural Network (BP-NN) are also implemented. Both SVM and BP-NN gives 84.31 % and 82.86 % overall accuracies respectively. Inception-v3 and VGGNet gives 89.43 % of overall accuracy using fine-tuned VGGNet and 92.10 % when using Inception-v3. The results indicate high accuracy of proposed fine-tuned ConvNets on a 4-channel Sentinel-2 dataset for built-up area extraction.

EXTRACTION OF BUILT-UP AREAS USING CONVOLUTIONAL NEURAL NETWORKS AND TRANSFER LEARNING FROM SENTINEL-2 SATELLITE IMAGES

Directory of Open Access Journals (Sweden)

V. S. Bramhe

2018-04-01

Full Text Available With rapid globalization, the extent of built-up areas is continuously increasing. Extraction of features for classifying built-up areas that are more robust and abstract is a leading research topic from past many years. Although, various studies have been carried out where spatial information along with spectral features has been utilized to enhance the accuracy of classification. Still, these feature extraction techniques require a large number of user-specific parameters and generally application specific. On the other hand, recently introduced Deep Learning (DL techniques requires less number of parameters to represent more abstract aspects of the data without any manual effort. Since, it is difficult to acquire high-resolution datasets for applications that require large scale monitoring of areas. Therefore, in this study Sentinel-2 image has been used for built-up areas extraction. In this work, pre-trained Convolutional Neural Networks (ConvNets i.e. Inception v3 and VGGNet are employed for transfer learning. Since these networks are trained on generic images of ImageNet dataset which are having very different characteristics from satellite images. Therefore, weights of networks are fine-tuned using data derived from Sentinel-2 images. To compare the accuracies with existing shallow networks, two state of art classifiers i.e. Gaussian Support Vector Machine (SVM and Back-Propagation Neural Network (BP-NN are also implemented. Both SVM and BP-NN gives 84.31 % and 82.86 % overall accuracies respectively. Inception-v3 and VGGNet gives 89.43 % of overall accuracy using fine-tuned VGGNet and 92.10 % when using Inception-v3. The results indicate high accuracy of proposed fine-tuned ConvNets on a 4-channel Sentinel-2 dataset for built-up area extraction.

Transferability of species distribution models for the detection of an invasive alien bryophyte using imaging spectroscopy data

Science.gov (United States)

Skowronek, Sandra; Van De Kerchove, Ruben; Rombouts, Bjorn; Aerts, Raf; Ewald, Michael; Warrie, Jens; Schiefer, Felix; Garzon-Lopez, Carol; Hattab, Tarek; Honnay, Olivier; Lenoir, Jonathan; Rocchini, Duccio; Schmidtlein, Sebastian; Somers, Ben; Feilhauer, Hannes

2018-06-01

Remote sensing is a promising tool for detecting invasive alien plant species. Mapping and monitoring those species requires accurate detection. So far, most studies relied on models that are locally calibrated and validated against available field data. Consequently, detecting invasive alien species at new study areas requires the acquisition of additional field data which can be expensive and time-consuming. Model transfer might thus provide a viable alternative. Here, we mapped the distribution of the invasive alien bryophyte Campylopus introflexus to i) assess the feasibility of spatially transferring locally calibrated models for species detection between four different heathland areas in Germany and Belgium and ii) test the potential of combining calibration data from different sites in one species distribution model (SDM). In a first step, four different SDMs were locally calibrated and validated by combining field data and airborne imaging spectroscopy data with a spatial resolution ranging from 1.8 m to 4 m and a spectral resolution of about 10 nm (244 bands). A one-class classifier, Maxent, which is based on the comparison of probability densities, was used to generate all SDMs. In a second step, each model was transferred to the three other study areas and the performance of the models for predicting C. introflexus occurrences was assessed. Finally, models combining calibration data from three study areas were built and tested on the remaining fourth site. In this step, different combinations of Maxent modelling parameters were tested. For the local models, the area under the curve for a test dataset (test AUC) was between 0.57-0.78, while the test AUC for the single transfer models ranged between 0.45-0.89. For the combined models the test AUC was between 0.54-0.9. The success of transferring models calibrated in one site to another site highly depended on the respective study site; the combined models provided higher test AUC values than the locally

Error of the slanted edge method for measuring the modulation transfer function of imaging systems.

Science.gov (United States)

Xie, Xufen; Fan, Hongda; Wang, Hongyuan; Wang, Zebin; Zou, Nianyu

2018-03-01

The slanted edge method is a basic approach for measuring the modulation transfer function (MTF) of imaging systems; however, its measurement accuracy is limited in practice. Theoretical analysis of the slanted edge MTF measurement method performed in this paper reveals that inappropriate edge angles and random noise reduce this accuracy. The error caused by edge angles is analyzed using sampling and reconstruction theory. Furthermore, an error model combining noise and edge angles is proposed. We verify the analyses and model with respect to (i) the edge angle, (ii) a statistical analysis of the measurement error, (iii) the full width at half-maximum of a point spread function, and (iv) the error model. The experimental results verify the theoretical findings. This research can be referential for applications of the slanted edge MTF measurement method.

A comparison of Gd-BOPTA and Gd-DOTA for contrast-enhanced MRI of intracranial tumours

International Nuclear Information System (INIS)

Colosimo, C.; Knopp, M.V.; Barreau, X.; Gerardin, E.; Kirchin, M.A.; Guezenoc, F.; Lodemann, K.P.

2004-01-01

A two-centre intra-individual crossover study was performed in 23 patients with suspected high-grade glioma or metastases to assess and compare the safety and enhancement characteristics of two different MRI contrast media (gadobenate dimeglumine, Gd-BOPTA and gadoterate meglumine, Gd-DOTA) at equivalent doses of 0.1 mmol/kg body weight. T1-weighted spin-echo (SE) and T2-weighted fast SE images were obtained before and T1-weighted images 0, 2, 4, 6, 8 and 15 min after injection. T1-weighted images with magnetisation transfer contrast were acquired 12 min after injection. Qualitative assessment by blinded, off-site readers (reader 1: 19 patients; reader 2: 21) and on-site investigators (23) revealed significant (P ≤0.005) overall preference for Gd-BOPTA over Gd-DOTA for contrast enhancement (Gd-BOPTA preferred in 18, 15 and 18 cases; Gd-DOTA in 0, 1 and 1 and no preference in 1, 5 and 4; off-site readers 1 and 2, and on-site investigators, respectively). A similar significant preference for Gd-BOPTA was expressed by off-site readers and on-site investigators for lesion-to-brain contrast, lesion delineation, internal lesion structure, and overall image preference. Quantitative assessment by off-site readers revealed significantly (p<0.05) greater lesion enhancement with Gd-BOPTA than with Gd-DOTA at all times from 2 min after injection. (orig.)

Partially coherent imaging and spatial coherence wavelets

International Nuclear Information System (INIS)

Castaneda, Roman

2003-03-01

A description of spatially partially coherent imaging based on the propagation of second order spatial coherence wavelets and marginal power spectra (Wigner distribution functions) is presented. In this dynamics, the spatial coherence wavelets will be affected by the system through its elementary transfer function. The consistency of the model with the both extreme cases of full coherent and incoherent imaging was proved. In the last case we obtained the classical concept of optical transfer function as a simple integral of the elementary transfer function. Furthermore, the elementary incoherent response function was introduced as the Fourier transform of the elementary transfer function. It describes the propagation of spatial coherence wavelets form each object point to each image point through a specific point on the pupil planes. The point spread function of the system was obtained by a simple integral of the elementary incoherent response function. (author)

Ethernet image communication performance in a multimodal PACS network

International Nuclear Information System (INIS)

Lou, S.L.; Valentino, D.J.; Chan, K.K.; Huang, H.K.

1989-01-01

The authors have evaluated the performance of an Ethernet network in a multimodal picture archiving and communications system (PACS) environment. The study included measurements between Sun workstations and PC- AT computers running communication software at the TCP level. First they initiated image transfers between two workstations, a server and a client. Next, they successively added clients to transfer images to the server and they measured degradation in network performance. Finally, they initiated image transfers between pairs of workstations and again measured performance degradation. The results of the authors' experiments indicate that Ethernet is suitable for image communication only in limited network situations. They discuss how to maximize network performance given these constraints

Transfer Mispricing as an Argument for Corporate Social Responsibility

OpenAIRE

Asongu, Simplice; Nwachukwu, Jacinta C.

2016-01-01

This article presents a case for transfer mispricing as an argument for Corporate Social Responsibility (CSR). The argument builds on the position that in order to compensate for potential loss of brand image and reputation, Multinational Companies (MNCs) would be more socially responsible when they are operating in countries where the legislation and laws in place are not effective at identifying and sanctioning transfer mispricing. We first discuss the dark side of transfer pricing (TP), ne...

CHARACTERIZING RESIDUE TRANSFER EFFICIENCIES USING A FLUORESCENT IMAGING TECHNIQUE

Science.gov (United States)

To reduce the uncertainty associated with current estimates of children's exposure to pesticides by dermal contact and indirect ingestion, residue transfer data are required. Prior to conducting exhaustive studies, a screening study to identify the important parameters for chara...

Do basic psychomotor skills transfer between different image-based procedures?

Science.gov (United States)

Buzink, Sonja N; Goossens, Richard H M; Schoon, Erik J; de Ridder, Huib; Jakimowicz, Jack J

2010-05-01

Surgical techniques that draw from multiple types of image-based procedures (IBP) are increasing, such as Natural Orifice Transluminal Endoscopic Surgery, fusing laparoscopy and flexible endoscopy. However, little is known about the relation between psychomotor skills for performing different types of IBP. For example, do basic psychomotor colonoscopy and laparoscopy skills interact? Following a cross-over study design, 29 naïve endoscopists were trained on the Simbionix GI Mentor and the SimSurgery SEP simulators. Group C (n = 15) commenced with a laparoscopy session, followed by four colonoscopy sessions and a second laparoscopy session. Group L (n = 14) started with a colonoscopy session, followed by four laparoscopy sessions and a second colonoscopy session. No significant differences were found between the performances of group L and group C in their first training sessions on either technique. With additional colonoscopy training, group C outperformed group L in the second laparoscopy training session on the camera navigation task. Overall, training in the basic colonoscopy tasks does not affect performance of basic laparoscopy tasks (and vice versa). However, to limited extent, training of basic psychomotor skills for colonoscopy do appear to contribute to the performance of angled laparoscope navigation tasks. Thus, training and assessment of IBP type-specific skills should focus on each type of tasks independently. Future research should further investigate the influence of psychometric abilities on the performance of IBP and the transfer of skills for physicians who are experienced in one IBP type and would like to become proficient in another type of IBP.

Potential for PET scanning as an aid to heat transfer modeling

International Nuclear Information System (INIS)

Samulski, T.V.; Harris, C.; Winget, J.M.; Dewhirst, M.W.

1987-01-01

Positron Emission Tomography (PET) using /sup 68/Ga labelled microspheres (15μ diam.) for quantitative imaging of perfusion is being investigated for its potential to aid in verification of parameter estimation techniques. Such techniques have been used in bioheat transfer modeling where direct measurement of perfusion has not been possible. Perfusion is needed, to utilize bioheat transfer to predict temperatures between measured points during hyperthermia therapy. A preliminary study showing that PET could be used for verification of parameter estimation was done by heating a melanoma in a dog in which multiple thermometry catheters were placed in a central plane. Microspheres were injected at the end of a one hour heat treatment session before power down. CT and PET images of the same plane were aligned so that relative counts/pixel in 2 cm regions of interest of the PET image were measured along several catheter tracks. In all tracks measured an inverse correlation was shown between relative perfusion and temperature along the catheter during thermal steady state. These data strongly imply that PET scans obtained in the manner described bear relevance to bioheat transfer and for verification of perfusion in heated tissues as estimated by heat transfer modeling

Optimization of the alpha image reconstruction. An iterative CT-image reconstruction with well-defined image quality metrics

Energy Technology Data Exchange (ETDEWEB)

Lebedev, Sergej; Sawall, Stefan; Knaup, Michael; Kachelriess, Marc [German Cancer Research Center, Heidelberg (Germany).

2017-10-01

Optimization of the AIR-algorithm for improved convergence and performance. TThe AIR method is an iterative algorithm for CT image reconstruction. As a result of its linearity with respect to the basis images, the AIR algorithm possesses well defined, regular image quality metrics, e.g. point spread function (PSF) or modulation transfer function (MTF), unlike other iterative reconstruction algorithms. The AIR algorithm computes weighting images α to blend between a set of basis images that preferably have mutually exclusive properties, e.g. high spatial resolution or low noise. The optimized algorithm uses an approach that alternates between the optimization of rawdata fidelity using an OSSART like update and regularization using gradient descent, as opposed to the initially proposed AIR using a straightforward gradient descent implementation. A regularization strength for a given task is chosen by formulating a requirement for the noise reduction and checking whether it is fulfilled for different regularization strengths, while monitoring the spatial resolution using the voxel-wise defined modulation transfer function for the AIR image. The optimized algorithm computes similar images in a shorter time compared to the initial gradient descent implementation of AIR. The result can be influenced by multiple parameters that can be narrowed down to a relatively simple framework to compute high quality images. The AIR images, for instance, can have at least a 50% lower noise level compared to the sharpest basis image, while the spatial resolution is mostly maintained. The optimization improves performance by a factor of 6, while maintaining image quality. Furthermore, it was demonstrated that the spatial resolution for AIR can be determined using regular image quality metrics, given smooth weighting images. This is not possible for other iterative reconstructions as a result of their non linearity. A simple set of parameters for the algorithm is discussed that provides

Optimization of the alpha image reconstruction. An iterative CT-image reconstruction with well-defined image quality metrics

International Nuclear Information System (INIS)

Lebedev, Sergej; Sawall, Stefan; Knaup, Michael; Kachelriess, Marc

2017-01-01

Optimization of the AIR-algorithm for improved convergence and performance. TThe AIR method is an iterative algorithm for CT image reconstruction. As a result of its linearity with respect to the basis images, the AIR algorithm possesses well defined, regular image quality metrics, e.g. point spread function (PSF) or modulation transfer function (MTF), unlike other iterative reconstruction algorithms. The AIR algorithm computes weighting images α to blend between a set of basis images that preferably have mutually exclusive properties, e.g. high spatial resolution or low noise. The optimized algorithm uses an approach that alternates between the optimization of rawdata fidelity using an OSSART like update and regularization using gradient descent, as opposed to the initially proposed AIR using a straightforward gradient descent implementation. A regularization strength for a given task is chosen by formulating a requirement for the noise reduction and checking whether it is fulfilled for different regularization strengths, while monitoring the spatial resolution using the voxel-wise defined modulation transfer function for the AIR image. The optimized algorithm computes similar images in a shorter time compared to the initial gradient descent implementation of AIR. The result can be influenced by multiple parameters that can be narrowed down to a relatively simple framework to compute high quality images. The AIR images, for instance, can have at least a 50% lower noise level compared to the sharpest basis image, while the spatial resolution is mostly maintained. The optimization improves performance by a factor of 6, while maintaining image quality. Furthermore, it was demonstrated that the spatial resolution for AIR can be determined using regular image quality metrics, given smooth weighting images. This is not possible for other iterative reconstructions as a result of their non linearity. A simple set of parameters for the algorithm is discussed that provides

Measurement of the modulation transfer function of a charge-coupled device array by the combination of the self-imaging effect and slanted edge method.

Science.gov (United States)

Najafi, Sedigheh; Madanipour, Khosro

2013-07-01

In this paper, by a combination of the self-imaging effect for Ronchi gratings and the standard slanted edge modulation transfer function (MTF) measurement method for CCD cameras, the MTF of the CCD array without optics is measured. For this purpose, a Ronchi-type grating is illuminated by an expanded He-Ne laser. A self-image of the grating appears without optics on the CCD array that is located on the Talbot distance. The lines of the self-image of the grating are used as a slanted edge array. This method has all the advantages of the slanted edge method, and also since the array of the edge is ready, the total area of the CCD can be tested. The measured MTF is related to the CCD array without optics.

Assessment of maxillary sinus volume for the sinus lift operation by three-dimensional magnetic resonance imaging.

Science.gov (United States)

Gray, C F; Staff, R T; Redpath, T W; Needham, G; Renny, N M

2000-05-01

To calculate sinus and bone graft volumes and vertical bone heights from sequential magnetic resonance imaging (MRI) examinations in patients undergoing a sinus lift operation. MRI scans were obtained pre-operatively and at 10 days and 10 weeks post-operatively, using a 0.95 tesla MRI scanner and a three-dimensional (3D) magnetisation prepared, rapid acquisition gradient-echo (MP-RAGE) sequence. Estimates of the bone graft volumes required for a desired vertical bone height were made from the pre-operative MRI scan. Measurements of the graft volumes and bone heights actually achieved were made from the post-operative scans. The MRI appearance of the graft changed between the 10 day and 10 week scans. We have proposed a technique which has the potential to give the surgeon an estimate of the optimum volume of graft for the sinus lift operation from the pre-operative MRI scan alone and demonstrated its application in a single patient. Changes in the sequential MRI appearance of the graft are consistent with replacement of fluid by a matrix of trabecular bone.

Influence of transfer gate design and bias on the radiation hardness of pinned photodiode CMOS image sensors

International Nuclear Information System (INIS)

Goiffon, V.; Estribeau, M.; Cervantes, P.; Molina, R.; Magnan, P.; Gaillardin, M.

2014-01-01

The effects of Cobalt 60 gamma-ray irradiation on pinned photodiode (PPD) CMOS image sensors (CIS) are investigated by comparing the total ionizing dose (TID) response of several transfer gate (TG) and PPD designs manufactured using a 180 nm CIS process. The TID induced variations of charge transfer efficiency (CTE), pinning voltage, equilibrium full well capacity (EFWC), full well capacity (FWC) and dark current measured on the different pixel designs lead to the conclusion that only three degradation sources are responsible for all the observed radiation effects: the pre-metal dielectric (PMD) positive trapped charge, the TG sidewall spacer positive trapped charge and, with less influence, the TG channel shallow trench isolation (STI) trapped charge. The different FWC evolutions with TID presented here are in very good agreement with a recently proposed analytical model. This work also demonstrates that the peripheral STI is not responsible for the observed degradations and thus that the enclosed layout TG design does not improve the radiation hardness of PPD CIS. The results of this study also lead to the conclusion that the TG OFF voltage bias during irradiation has no influence on the radiation effects. Alternative design and process solutions to improve the radiation hardness of PPD CIS are discussed. (authors)

Concept of contrast transfer function for edge illumination x-ray phase-contrast imaging and its comparison with the free-space propagation technique.

Science.gov (United States)

Diemoz, Paul C; Vittoria, Fabio A; Olivo, Alessandro

2016-05-16

Previous studies on edge illumination (EI) X-ray phase-contrast imaging (XPCi) have investigated the nature and amplitude of the signal provided by this technique. However, the response of the imaging system to different object spatial frequencies was never explicitly considered and studied. This is required in order to predict the performance of a given EI setup for different classes of objects. To this scope, in the present work we derive analytical expressions for the contrast transfer function of an EI imaging system, using the approximation of near-field regime, and study its dependence upon the main experimental parameters. We then exploit these results to compare the frequency response of an EI system with respect of that of a free-space propagation XPCi one. The results achieved in this work can be useful for predicting the signals obtainable for different types of objects and also as a basis for new retrieval methods.

Improved cloning efficiency and developmental potential in bovine somatic cell nuclear transfer with the oosight imaging system.

Science.gov (United States)

Kim, Eun Young; Park, Min Jee; Park, Hyo Young; Noh, Eun Ji; Noh, Eun Hyung; Park, Kyoung Sik; Lee, Jun Beom; Jeong, Chang Jin; Riu, Key Zung; Park, Se Pill

2012-08-01

In somatic cell nuclear transfer (SCNT) procedures, exquisite enucleation of the recipient oocyte is critical to cloning efficiency. The purpose of this study was to compare the effects of two enucleation systems, Hoechst staining and UV irradiation (hereafter, irradiation group) and Oosight imaging (hereafter, Oosight group), on the in vitro production of bovine SCNT embryos. In the Oosight group, the apoptotic index (2.8 ± 0.5 vs. 7.3 ± 1.2) was lower, and the fusion rate (75.6% vs. 62.9%), cleavage rate (78.0% vs. 63.7%), blastocyst rate (40.2% vs. 29.2%), and total cell number (128.3±4.8 vs. 112.2 ± 7.6) were higher than those in the irradiation group (all p<0.05). The overall efficiency after SCNT was twice as high in the Oosight group as that in the irradiation group (p<0.05). The relative mRNA expression levels of Oct4, Nanog, Interferon-tau, and Dnmt3A were higher and those of Caspase-3 and Hsp70 were lower in the Oosight group compared with the irradiation group (p<0.05). This is the first report to show the positive effect of the Oosight imaging system on molecular gene expression in the SCNT embryo. The Oosight imaging system may become the preferred choice for enucleation because it is less detrimental to the developmental potential of bovine SCNT embryos.

Amide proton transfer imaging to discriminate between low- and high-grade gliomas: added value to apparent diffusion coefficient and relative cerebral blood volume

Energy Technology Data Exchange (ETDEWEB)

Choi, Yoon Seong; Ahn, Sung Soo; Lee, Seung-Koo [Yonsei University College of Medicine, Department of Radiology and Research Institute of Radiological Science, College of Medicine, Seoul (Korea, Republic of); Chang, Jong Hee; Kang, Seok-Gu [Yonsei University College of Medicine, Department of Neurosurgery, Seoul (Korea, Republic of); Kim, Se Hoon [Yonsei University College of Medicine, Department of Pathology, Seoul (Korea, Republic of); Zhou, Jinyuan [Johns Hopkins University School of Medicine, Division of MRI Research, Department of Radiology, Baltimore, MD (United States)

2017-08-15

To evaluate the added value of amide proton transfer (APT) imaging to the apparent diffusion coefficient (ADC) from diffusion tensor imaging (DTI) and the relative cerebral blood volume (rCBV) from perfusion magnetic resonance imaging (MRI) for discriminating between high- and low-grade gliomas. Forty-six consecutive adult patients with diffuse gliomas who underwent preoperative APT imaging, DTI and perfusion MRI were enrolled. APT signals were compared according to the World Health Organization grade. The diagnostic ability and added value of the APT signal to the ADC and rCBV for discriminating between low- and high-grade gliomas were evaluated using receiver operating characteristic (ROC) analyses and integrated discrimination improvement. The APT signal increased as the glioma grade increased. The discrimination abilities of the APT, ADC and rCBV values were not significantly different. Using both the APT signal and ADC significantly improved discrimination vs. the ADC alone (area under the ROC curve [AUC], 0.888 vs. 0.910; P = 0.007), whereas using both the APT signal and rCBV did not improve discrimination vs. the rCBV alone (AUC, 0.927 vs. 0.923; P = 0.222). APT imaging may be a useful imaging biomarker that adds value to the ADC for discriminating between low- and high-grade gliomas. (orig.)

Factors associated with imaging overuse in the emergency department: A systematic review.

Science.gov (United States)

Tung, Monica; Sharma, Ritu; Hinson, Jeremiah S; Nothelle, Stephanie; Pannikottu, Jean; Segal, Jodi B

2018-02-01

Emergency departments (ED) are sites of prevalent imaging overuse; however, determinants that drive imaging in this setting are not well-characterized. We systematically reviewed the literature to summarize the determinants of imaging overuse in the ED. We searched MEDLINE® and Embase® from January 1998 to March 2017. Studies were included if they were written in English, contained original data, pertained to a U.S. population, and identified a determinant associated with overuse of imaging in the ED. Twenty relevant studies were included. Fourteen evaluated computerized tomography (CT) scanning in patents presenting to a regional ED who were then transferred to a level 1 trauma center; incomplete transfer of data and poor image quality were the most frequently described reasons for repeat scanning. Unnecessary pre-transfer scanning or repeated scanning after transfer, in multiple studies, was highest among older patients, those with higher Injury Severity Scores (ISS) and those being transferred further. Six studies explored determinants of overused imaging in the ED in varied conditions, with overuse greater in older patients and those having more comorbid diseases. Defensive imaging reportedly influenced physician behavior. Less integration of services across the health system also predisposed to overuse of imaging. The literature is heterogeneous with surprisingly few studies of determinants of imaging in minor head injury or of spine imaging. Older patient age and higher ISS were the most consistently associated with ED imaging overuse. This review highlights the need for precise definitions of overuse of imaging in the ED. Copyright © 2017 Elsevier Inc. All rights reserved.

Umbrella sampling of proton transfer in a creatine-water system

Science.gov (United States)

Ivchenko, Olga; Bachert, Peter; Imhof, Petra

2014-04-01

Proton transfer reactions are among the most common processes in chemistry and biology. Proton transfer between creatine and surrounding solvent water is underlying the chemical exchange saturation transfer used as a contrast in magnetic resonance imaging. The free energy barrier, determined by first-principles umbrella sampling simulations (EaDFT 3 kcal/mol) is in the same order of magnitude as the experimentally obtained activation energy. The underlying mechanism is a first proton transfer from the guanidinium group to the water pool, followed by a second transition where a proton is "transferred back" from the nearest water molecule to the deprotonated nitrogen atom of creatine.

Simulation of seagrass bed mapping by satellite images based on the radiative transfer model

Science.gov (United States)

Sagawa, Tatsuyuki; Komatsu, Teruhisa

2015-06-01

Seagrass and seaweed beds play important roles in coastal marine ecosystems. They are food sources and habitats for many marine organisms, and influence the physical, chemical, and biological environment. They are sensitive to human impacts such as reclamation and pollution. Therefore, their management and preservation are necessary for a healthy coastal environment. Satellite remote sensing is a useful tool for mapping and monitoring seagrass beds. The efficiency of seagrass mapping, seagrass bed classification in particular, has been evaluated by mapping accuracy using an error matrix. However, mapping accuracies are influenced by coastal environments such as seawater transparency, bathymetry, and substrate type. Coastal management requires sufficient accuracy and an understanding of mapping limitations for monitoring coastal habitats including seagrass beds. Previous studies are mainly based on case studies in specific regions and seasons. Extensive data are required to generalise assessments of classification accuracy from case studies, which has proven difficult. This study aims to build a simulator based on a radiative transfer model to produce modelled satellite images and assess the visual detectability of seagrass beds under different transparencies and seagrass coverages, as well as to examine mapping limitations and classification accuracy. Our simulations led to the development of a model of water transparency and the mapping of depth limits and indicated the possibility for seagrass density mapping under certain ideal conditions. The results show that modelling satellite images is useful in evaluating the accuracy of classification and that establishing seagrass bed monitoring by remote sensing is a reliable tool.

Image-Based Modeling of Blood Flow and Oxygen Transfer in Feto-Placental Capillaries.

Directory of Open Access Journals (Sweden)

Philip Pearce

Full Text Available During pregnancy, oxygen diffuses from maternal to fetal blood through villous trees in the placenta. In this paper, we simulate blood flow and oxygen transfer in feto-placental capillaries by converting three-dimensional representations of villous and capillary surfaces, reconstructed from confocal laser scanning microscopy, to finite-element meshes, and calculating values of vascular flow resistance and total oxygen transfer. The relationship between the total oxygen transfer rate and the pressure drop through the capillary is shown to be captured across a wide range of pressure drops by physical scaling laws and an upper bound on the oxygen transfer rate. A regression equation is introduced that can be used to estimate the oxygen transfer in a capillary using the vascular resistance. Two techniques for quantifying the effects of statistical variability, experimental uncertainty and pathological placental structure on the calculated properties are then introduced. First, scaling arguments are used to quantify the sensitivity of the model to uncertainties in the geometry and the parameters. Second, the effects of localized dilations in fetal capillaries are investigated using an idealized axisymmetric model, to quantify the possible effect of pathological placental structure on oxygen transfer. The model predicts how, for a fixed pressure drop through a capillary, oxygen transfer is maximized by an optimal width of the dilation. The results could explain the prevalence of fetal hypoxia in cases of delayed villous maturation, a pathology characterized by a lack of the vasculo-syncytial membranes often seen in conjunction with localized capillary dilations.

Preliminary modulation transfer function study on amorphous silicon

International Nuclear Information System (INIS)

Khairul Anuar Mohd Salleh; Ab Razak Hamzah; Mohd Ashhar Khalid

2006-01-01

Modulation Transfer Function, (MTF) is the scientific means of evaluating the fundamental spatial resolution performance of an imaging system. In the study, the modulation transfer function of an amorphous silicon (aSi) sensor array is measured by using Edge Spread Function (ESF) Technique which is extracting a profile from the linearised image of the sharp edge. The Platinum foil is used to determine the ESF. The detector under study was a 2,304 (h) x 3,200 (v) total pixel matrix, 127 μm2 pixel pitch, 57% fill factor and using Gd2O2S:Tb Kodak Lanex Regular as the conversion screen. The ESF measurement is done by using 75 - 100 kV range of x-ray with constant mA. (Author)

Unsupervised Typography Transfer

OpenAIRE

Sun, Hanfei; Luo, Yiming; Lu, Ziang

2018-01-01

Traditional methods in Chinese typography synthesis view characters as an assembly of radicals and strokes, but they rely on manual definition of the key points, which is still time-costing. Some recent work on computer vision proposes a brand new approach: to treat every Chinese character as an independent and inseparable image, so the pre-processing and post-processing of each character can be avoided. Then with a combination of a transfer network and a discriminating network, one typograph...

Added value of amide proton transfer imaging to conventional and perfusion MR imaging for evaluating the treatment response of newly diagnosed glioblastoma

Energy Technology Data Exchange (ETDEWEB)

Park, Kye Jin; Kim, Ho Sung; Park, Ji Eun; Shim, Woo Hyun; Kim, Sang Joon [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of); Smith, Seth A. [Vanderbilt University Institute of Imaging Science, Vanderbilt University, Department of Radiology and Radiological Sciences, Nashville, TN (United States)

2016-12-15

To determine the added value of amide proton transfer (APT) imaging to conventional and perfusion MRI for differentiating tumour progression (TP) from the treatment-related effect (TE) in patients with post-treatment glioblastomas. Sixty-five consecutive patients with enlarging contrast-enhancing lesions following concurrent chemoradiotherapy were assessed using contrast-enhanced T1-weighted MRI (CE-T1WI), 90th percentile histogram parameters of normalized cerebral blood volume (nCBV90) and APT asymmetry value (APT90). Diagnostic performance was determined using the area under the receiver operating characteristic curve (AUC) and cross validations. There were statistically significant differences in the mean APT90 between the TP and the TE groups (3.87-4.01 % vs. 1.38-1.41 %; P <.001). Compared with CE-T1WI alone, the addition of APT90 to CE-T1WI significantly improved cross-validated AUC from 0.58-0.74 to 0.89-0.91 for differentiating TP from TE. The combination of CE-T1WI, nCBV90 and APT90 resulted in greater diagnostic accuracy for differentiating TP from TE than the combination of CE-T1WI and nCBV90 (cross-validated AUC, 0.95-0.97 vs. 0.84-0.91). The inter-reader agreement between the expert and trainee was excellent for the measurements of APT90 (intraclass correlation coefficient, 0.94). Adding APT imaging to conventional and perfusion MRI improves the diagnostic performance for differentiating TP from TE. (orig.)

Image viewing station for MR and SPECT : using personal computer

International Nuclear Information System (INIS)

Yim, Byung Il; Jeong, Eun Kee; Suh, Jin Suck; Kim, Myeong Joon

1996-01-01

Macro language was programmed to analyze and process on Macintosh personal computers, GEMR images digitally transferred from the MR main computer, with special interest in the interpretation of information such as patients data and imaging parameters under each image header. By this method, raw data(files) of certain patients may be digitally stored on a hard disk or CD ROM, and the quantitative analysis, interpretation and display is possible. Patients and images were randomly selected 4.X MR images were transferred through FTP using the ethernet network. 5.X and SPECT images were transferred using floppy diskettes. To process transferred images, an freely distributed software for Macintosh namely NIH Image, with its macro language, was used to import images and translate header information. To identify necessary information, a separate window named I nfo=txt , was made for each image series. MacLC, Centris650, and PowerMac6100/CD, 7100/CD, 8100/CD models with 256 color and RAM over 8Mbyte were used. Different versions of MR images and SPECT images were displayed simultaneously and a separate window named 'info-txt' was used to show all necessary information(name of the patient, unit number, date, TR, TE, FOV etc.). Additional information(diagnosis, pathologic report etc.) was stored in another text box in 'info-txt'. The size of the file for each image plane was about 149Kbytes and the images were stored in a step-like file folders. 4.X and 5.X GE Signa 1.5T images were successfully processed with Macintosh computer and NIH Image. This result may be applied to many fields and there is hope of a broader area of application with the linkage of NIH Image and a database program

A study of nanosized magnesium ferrite particles with high magnetic moment

Energy Technology Data Exchange (ETDEWEB)

Sumangala, T.P.; Mahender, C.; Venkataramani, N. [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, 400076 Mumbai (India); Prasad, Shiva, E-mail: shiva.pd@gmail.com [Department of Physics, Indian Institute of Technology Bombay, Powai, 400076 Mumbai (India)

2015-05-15

Nano-sized magnesium ferrite particles were prepared by sol gel combustion synthesis and were either furnace cooled or quenched after calcining at various temperatures ranging from 300 to 800 °C. A magnetisation value of 61 emu/g was obtained at 5 K for sample calcined at 800 °C and quenched in liquid nitrogen temperature. This is one of the highest reported values of magnetisation obtained from quenching at such a lower temperature. An estimate of the number of Fe{sup 3+} ions on A and B sites was made after applying Néel Model on the magnetisation values measured at 5 K. It was estimated that Fe{sup 3+} ions segregates out from both sites disproportionately so as to cause a net decrease in the overall moment. The resultant cation distribution is found to be consistent with the coercivity data. - Highlights: • Highest magnetisation (M) among nano sized magnesium ferrite particles was obtained. • The obtained magnetisation was nearly double of furnace cooled bulk sample. • Coercivity (H{sub c}) is anti correlated to M for samples with different heat treatment. • Coefficient of non saturation of magnetisation in M–H loop (a), is correlated with H{sub c}. • H{sub c}, M and a are explained in terms of cation distribution obtained using NNéel model.

A technique for transferring a patient's smile line to a cone beam computed tomography (CBCT) image.

Science.gov (United States)

Bidra, Avinash S

2014-08-01

Fixed implant-supported prosthodontic treatment for patients requiring a gingival prosthesis often demands that bone and implant levels be apical to the patient's maximum smile line. This is to avoid the display of the prosthesis-tissue junction (the junction between the gingival prosthesis and natural soft tissues) and prevent esthetic failures. Recording a patient's lip position during maximum smile is invaluable for the treatment planning process. This article presents a simple technique for clinically recording and transferring the patient's maximum smile line to cone beam computed tomography (CBCT) images for analysis. The technique can help clinicians accurately determine the need for and amount of bone reduction required with respect to the maximum smile line and place implants in optimal positions. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Heat transfer enhancement using 2MHz ultrasound.

Science.gov (United States)

Bulliard-Sauret, Odin; Ferrouillat, Sebastien; Vignal, Laure; Memponteil, Alain; Gondrexon, Nicolas

2017-11-01

The present work focuses on possible heat transfer enhancement from a heating plate towards tap water in forced convection by means of 2MHz ultrasound. The thermal approach allows to observe the increase of local convective heat transfer coefficients in the presence of ultrasound and to deduce a correlation between ultrasound power and Nusselt number. Heat transfer coefficient under ultrasound remains constant while heat transfer coefficient under silent conditions increases with Reynolds number from 900 up to 5000. Therefore, heat transfer enhancement factor ranges from 25% up to 90% for the same energy conditions (supplied ultrasonic power=110W and supplied thermal power=450W). In the same time cavitational activity due to 2MHz ultrasound emission was characterized from mechanical and chemical viewpoints without significant results. At least, Particle Image Velocimetry (PIV) measurements have been performed in order to investigate hydrodynamic modifications due to the presence of 2MHz ultrasound. It was therefore possible to propose a better understanding of heat transfer enhancement mechanism with high frequency ultrasound. Copyright © 2017 Elsevier B.V. All rights reserved.

Imaging living central neurones using viral gene transfer.

Science.gov (United States)

Teschemacher, A G; Paton, J F R; Kasparov, S

2005-01-02

Studies of central neurones and other cellular components of the brain, such as glial and vascular cells, can be greatly advanced by the use of the modern optical techniques such as confocal live cell imaging. Fluorescent proteins have allowed imaging of particular cell types or intracellular elements to be visualised and distinguished from irrelevant background structures. To introduce the genetic information encoding for fluorescent proteins into relevant cellular targets, molecular tools are required. Viral vectors are one of the best ways of gene delivery into differentiated postnatal brain neurones and glia. Current progress in this field allows targeting of various cell types and therefore makes it possible to express a variety of fluorescent constructs in selected subpopulations of neurones, for example. In this review, we will discuss and compare the properties of the most popular viral gene delivery systems and the advantages of different brain cell preparations to illustrate how they can be used for high-resolution live cell confocal imaging in order to study new aspects of central nervous system (CNS) structure and function.

Versatile Polymer-Free Graphene Transfer Method and Applications.

Science.gov (United States)

Zhang, Guohui; Güell, Aleix G; Kirkman, Paul M; Lazenby, Robert A; Miller, Thomas S; Unwin, Patrick R

2016-03-01

A new method for transferring chemical vapor deposition (CVD)-grown monolayer graphene to a variety of substrates is described. The method makes use of an organic/aqueous biphasic configuration, avoiding the use of any polymeric materials that can cause severe contamination problems. The graphene-coated copper foil sample (on which graphene was grown) sits at the interface between hexane and an aqueous etching solution of ammonium persulfate to remove the copper. With the aid of an Si/SiO2 substrate, the graphene layer is then transferred to a second hexane/water interface to remove etching products. From this new location, CVD graphene is readily transferred to arbitrary substrates, including three-dimensional architectures as represented by atomic force microscopy (AFM) tips and transmission electron microscopy (TEM) grids. Graphene produces a conformal layer on AFM tips, to the very end, allowing easy production of tips for conductive AFM imaging. Graphene transferred to copper TEM grids provides large-area, highly electron-transparent substrates for TEM imaging. These substrates can also be used as working electrodes for electrochemistry and high-resolution wetting studies. By using scanning electrochemical cell microscopy, it is possible to make electrochemical and wetting measurements at either a freestanding graphene film or a copper-supported graphene area and readily determine any differences in behavior.

Ship Detection Using Transfer Learned Single Shot Multi Box Detector

Directory of Open Access Journals (Sweden)

Nie Gu-Hong

2017-01-01

Full Text Available Ship detection in satellite images is a challenging task. In this paper, we introduce a transfer learned Single Shot MultiBox Detector (SSD for ship detection. To this end, a state-of-the-art object detection model pre-trained from a large number of natural images was transfer learned for ship detection with limited labeled satellite images. To the best of our knowledge, this could be one of the first studies which introduce SSD into ship detection on satellite images. Experiments demonstrated that our method could achieve 87.9% AP at 47 FPS using NVIDIA TITAN X. In comparison with Faster R-CNN, 6.7% AP improvement could be achieved. Effects of the observation resolution has also been studied with the changing input sizes among 300 × 300, 600 × 600 and 900 × 900. It has been noted that the detection accuracy declined sharply with the decreasing resolution that is mainly caused by the missing small ships.

RAPTOR. I. Time-dependent radiative transfer in arbitrary spacetimes

Science.gov (United States)

Bronzwaer, T.; Davelaar, J.; Younsi, Z.; Mościbrodzka, M.; Falcke, H.; Kramer, M.; Rezzolla, L.

2018-05-01

Context. Observational efforts to image the immediate environment of a black hole at the scale of the event horizon benefit from the development of efficient imaging codes that are capable of producing synthetic data, which may be compared with observational data. Aims: We aim to present RAPTOR, a new public code that produces accurate images, animations, and spectra of relativistic plasmas in strong gravity by numerically integrating the equations of motion of light rays and performing time-dependent radiative transfer calculations along the rays. The code is compatible with any analytical or numerical spacetime. It is hardware-agnostic and may be compiled and run both on GPUs and CPUs. Methods: We describe the algorithms used in RAPTOR and test the code's performance. We have performed a detailed comparison of RAPTOR output with that of other radiative-transfer codes and demonstrate convergence of the results. We then applied RAPTOR to study accretion models of supermassive black holes, performing time-dependent radiative transfer through general relativistic magneto-hydrodynamical (GRMHD) simulations and investigating the expected observational differences between the so-called fast-light and slow-light paradigms. Results: Using RAPTOR to produce synthetic images and light curves of a GRMHD model of an accreting black hole, we find that the relative difference between fast-light and slow-light light curves is less than 5%. Using two distinct radiative-transfer codes to process the same data, we find integrated flux densities with a relative difference less than 0.01%. Conclusions: For two-dimensional GRMHD models, such as those examined in this paper, the fast-light approximation suffices as long as errors of a few percent are acceptable. The convergence of the results of two different codes demonstrates that they are, at a minimum, consistent. The public version of RAPTOR is available at the following URL: http://https://github.com/tbronzwaer/raptor

A magnetization transfer imaging study of bilateral optic radiation and visual cortex in patients with primary glaucoma

International Nuclear Information System (INIS)

Liang Wenwen; Zhang Xuelin; Jiang Xiaoyong; Xu Yongming; Yang Zhihui; Zhang Yan; Chang Renmin; Wang Jianping; Wu Guijun

2012-01-01

Objective: To analyse the changes in bilateral optic radiation and visual cortex in patients with primary glaucoma detected by magnetization transfer imaging (MTI), and try to explore the influence of the disease on posterior visual pathway. Methods: MTI was performed in 20 patients with primary glaucoma with normal signal on conventional magnetic resonance imaging (MRI). The same scanning was performed in 31 matched healthy controls. MTI was obtained using spoiled gradient recalled acquisition sequence (SPGR). Magnetization transfer ratio (MTR) of bilateral optic radiation and visual cortex was measured after post-processing. The MTR value differences of the same area between two groups were compared by independent-sample t test or Satterthwaite t test if variances were not equality. Result: The MTR value in the left and right optic radiation were (32.8 ± 2.2)% and (32.7 ± 2.0)% in the glaucoma group, (34.6 ± 1.4 )% and (34.8 ± 1.3)% in the control group. There was a statistically significant difference between the two groups (left t=3.284, right t=4.040; P<0.01). The MTR value of the left and right visual cortex were (30.1± 2.0)% and (30.8 ± 1.8)% in the glaucoma group, and (32.3 ± 1.2 )% and (32.4 ± 1.2)% in the control group. Statistically significant difference was found between the two groups (left t=4.319, right t=3.445; P<0.01). Conclusions: Potential neuropathology changes occurring in the posterior visual pathway of patients with glaucoma indicate that the whole visual pathway may be involved by glaucoma.The micro physiological changes can be detected by MTI which can not be found by conventional MRI. It is a useful method of studying trans-synaptic damage of visual pathway n vivo glaucoma which provides more information for guiding the clinic diagnosis, cure and prognosis of glaucoma. (authors)

Imaging of placental transport mechanisms: a review.

Science.gov (United States)

Sölder, Elisabeth; Rohr, Irena; Kremser, Christian; Hutzler, Peter; Debbage, Paul L

2009-05-01

Functional analysis of material transfers requires precise statement of residence times in each tissue compartment. For the placenta, neither extractive biochemistry, isotope partitioning, nor mass-based quantitative assays provide adequate spatial resolution to allow the necessary precision. Dual-perfusion assays of material transfer in isolated placental cotyledons provide time-series data for two compartments, the maternal and fetal blood, but fail to distinguish the two cellular compartments (syncytiotrophoblast, fetal endothelium) which actively regulate rates of transfer in each direction for essentially every important molecule type. At present, no definitive technology exists for functional analysis of placental transfer functions. The challenge in developing such a technology lies in the exquisitely small and delicate structures involved, which are scaled at cellular and subcellular sizes (between 50 nm and 50 microm). The only available technologies attaining this high spatial resolution are imaging technologies, primarily light and electron microscopy. To achieve the high-quality images necessary, confocal laser scanning microscopy (CLSM) is required, to provide a uniform optical sectioning plane. In turn, this requires relatively high fluorescence intensities. Design of an adequate technology therefore bases on CLSM imaging fluorochrome-tagged tracers. The temporal resolution necessary to analyse placental material transfers is expected to be of the order of a few seconds, so that conventional wet-fixation protocols are too slow. For adequately rapid fixation, snap-freezing is required. As part of this review we report results obtained from an appropriately designed experimental protocol, analysed by CLSM and transmission electron microscopy (TEM). The images acquired were tested for uniformity of illumination and fluorescence emission strength. Relevant data was encoded in the green channel of the trichrome images obtained, and this was thresholded by

A NEW IMAGE REGISTRATION METHOD FOR GREY IMAGES

Institute of Scientific and Technical Information of China (English)

Nie Xuan; Zhao Rongchun; Jiang Zetao

2004-01-01

The proposed algorithm relies on a group of new formulas for calculating tangent slope so as to address angle feature of edge curves of image. It can utilize tangent angle features to estimate automatically and fully the rotation parameters of geometric transform and enable rough matching of images with huge rotation difference. After angle compensation, it can search for matching point sets by correlation criterion, then calculate parameters of affine transform, enable higher-precision emendation of rotation and transferring. Finally, it fulfills precise matching for images with relax-tense iteration method. Compared with the registration approach based on wavelet direction-angle features, the matching algorithm with tangent feature of image edge is more robust and realizes precise registration of various images. Furthermore, it is also helpful in graphics matching.

Quantitative luminescence imaging system

Science.gov (United States)

Erwin, David N.; Kiel, Johnathan L.; Batishko, Charles R.; Stahl, Kurt A.

1990-01-01

The QLIS images and quantifies low-level chemiluminescent reactions in an electromagnetic field. It is capable of real time nonperturbing measurement and simultaneous recording of many biochemical and chemical reactions such as luminescent immunoassays or enzyme assays. The system comprises image transfer optics, a low-light level digitizing camera with image intensifying microchannel plates, an image process or, and a control computer. The image transfer optics may be a fiber image guide with a bend, or a microscope, to take the light outside of the RF field. Output of the camera is transformed into a localized rate of cumulative digitalized data or enhanced video display or hard-copy images. The system may be used as a luminescent microdosimetry device for radiofrequency or microwave radiation, as a thermal dosimeter, or in the dosimetry of ultra-sound (sonoluminescence) or ionizing radiation. It provides a near-real-time system capable of measuring the extremely low light levels from luminescent reactions in electromagnetic fields in the areas of chemiluminescence assays and thermal microdosimetry, and is capable of near-real-time imaging of the sample to allow spatial distribution analysis of the reaction. It can be used to instrument three distinctly different irradiation configurations, comprising (1) RF waveguide irradiation of a small Petri-dish-shaped sample cell, (2) RF irradiation of samples in a microscope for the microscopie imaging and measurement, and (3) RF irradiation of small to human body-sized samples in an anechoic chamber.

Flow map and measurement of void fraction and heat transfer coefficient using an image analysis technique for flow boiling of water in a silicon microchannel

International Nuclear Information System (INIS)

Singh, S G; Duttagupta, S P; Jain, A; Sridharan, A; Agrawal, Amit

2009-01-01

The present work focuses on the generation of the flow regime map for two-phase water flow in microchannels of a hydraulic diameter of 140 µm. An image analysis algorithm has been developed and utilized to obtain the local void fraction. The image processing technique is also employed to identify and estimate the percentage of different flow regimes and heat transfer coefficient, as a function of position, heat flux and mass flow rate. Both void fraction and heat transfer coefficient are found to increase monotonically along the length of the microchannel. At low heat flux and low flow rates, bubbly, slug and annular flow regimes are apparent. However, the flow is predominately annular at high heat flux and high flow rate. A breakup of the flow frequency suggests that the flow is bistable in the annular regime, in that at a fixed location, the flow periodically switches from single-phase liquid to annular and vice versa. Otherwise, the occurrence of three regimes—single-phase liquid, bubbly and slug are observed. These results provide several useful insights about two-phase flow in microchannels besides being of fundamental interest

Infrared and visible image fusion based on total variation and augmented Lagrangian.

Science.gov (United States)

Guo, Hanqi; Ma, Yong; Mei, Xiaoguang; Ma, Jiayi

2017-11-01

This paper proposes a new algorithm for infrared and visible image fusion based on gradient transfer that achieves fusion by preserving the intensity of the infrared image and then transferring gradients in the corresponding visible one to the result. The gradient transfer suffers from the problems of low dynamic range and detail loss because it ignores the intensity from the visible image. The new algorithm solves these problems by providing additive intensity from the visible image to balance the intensity between the infrared image and the visible one. It formulates the fusion task as an l 1 -l 1 -TV minimization problem and then employs variable splitting and augmented Lagrangian to convert the unconstrained problem to a constrained one that can be solved in the framework of alternating the multiplier direction method. Experiments demonstrate that the new algorithm achieves better fusion results with a high computation efficiency in both qualitative and quantitative tests than gradient transfer and most state-of-the-art methods.

Transfer function restoration in 3D electron microscopy via iterative data refinement

International Nuclear Information System (INIS)

Sorzano, C O S; Marabini, R; Herman, G T; Censor, Y; Carazo, J M

2004-01-01

Three-dimensional electron microscopy (3D-EM) is a powerful tool for visualizing complex biological systems. As with any other imaging device, the electron microscope introduces a transfer function (called in this field the contrast transfer function, CTF) into the image acquisition process that modulates the various frequencies of the signal. Thus, the 3D reconstructions performed with these CTF-affected projections are also affected by an implicit 3D transfer function. For high-resolution electron microscopy, the effect of the CTF is quite dramatic and limits severely the achievable resolution. In this work we make use of the iterative data refinement (IDR) technique to ameliorate the effect of the CTF. It is demonstrated that the approach can be successfully applied to noisy data

Antibody responses to allergen Lol pIV are suppressed following adoptive transfer of B lymphocytes from the internal image anti-idiotypic antibody-treated mice.

Science.gov (United States)

Zhou, E M; Kisil, F T

1995-10-01

An internal image anti-idiotypic antibody, designated B1/1, was generated against an idiotope (Id91) of the monoclonal antibody (mAb91) specific for Lol pIV. The administration of B1/1 in PBS, at doses ranging from 100 ng to 100 micrograms/mouse, to syngeneic Balb/c mice resulted in the suppression of the formation of anti-Lol pIV antibodies that possessed the Id91. Spleen cells obtained from the mice 2 weeks after the treatment with B1/1 (25 micrograms/mouse) were adoptively transferred intravenously into the syngeneic recipients which were challenged intraperitoneally with Lol pIV in alum 2 hr after the transfer. The recipients were boosted with Lol pIV 14 days later. It was demonstrated that the transfer of splenic B cells (but not of T cells) from B1/1-treated donors induced a significant suppression of not only the level of IgE and IgG antibodies to Lol pIV, but also the level of antibodies possessing the Id91. Treatment of the B cells with mAb91 plus complement abrogated their ability to transfer the suppression. This study indicates that the treatment with the anti-Id B1/1 generated B cells that were characterized, serologically, as possessing the anti-Id-like antibodies on their surface and were responsible for transferring the suppression of the formation of antibodies to allergen Lol pIV and the expression of Id91.

Reproducibility, and age, body-weight and gender dependency of candidate skeletal muscle MRI outcome measures in healthy volunteers

International Nuclear Information System (INIS)

Morrow, Jasper M.; Reilly, Mary M.; Hanna, Michael G.; Sinclair, Christopher D.J.; Yousry, Tarek A.; Thornton, John S.; Fischmann, Arne

2014-01-01

Quantitative magnetic resonance imaging (MRI) can potentially meet the pressing need for objective, sensitive, reproducible outcome measures in neuromuscular disease trials. We tested, in healthy volunteers, the consistency, reliability and sensitivity to normal inter-subject variation of MRI methods targeted to lower limb muscle pathology to inform the design of practical but comprehensive MRI outcome measure protocols for use in imminent patient studies. Forty-seven healthy volunteers, age 21-81 years, were subject at 3T to three-point Dixon fat-fraction measurement, T 1 -relaxometry, T 2 -relaxometry and magnetisation transfer ratio (MTR) imaging at mid-thigh and mid-calf level bilaterally. Fifteen subjects underwent repeat imaging at 2 weeks. Mean between-muscle fat fraction and T 2 differences were small, but significant (p 2 correlated positively, and MTR negatively with subject age in both the thigh and calf, with similar significant correlations with weight at thigh level only (p < 0.001 to p < 0.05). Scan-rescan and inter-observer intra-class correlation coefficients ranged between 0.62-0.84 and 0.79-0.99 respectively. Quantitative lower-limb muscle MRI using readily implementable methods was sensitive enough to demonstrate inter-muscle differences (small in health), and correlations with subject age and weight. In combination with high reliability, this strongly supports the suitability of these methods to provide longitudinal outcome measures in neuromuscular disease treatment trials. (orig.)

Comprehensive study of flow and heat transfer at the surface of circular cooling fin

Science.gov (United States)

Mityakov, V. Yu; Grekov, M. A.; Gusakov, A. A.; Sapozhnikov, S. Z.; Seroshtanov, V. V.; Bashkatov, A. V.; Dymkin, A. N.; Pavlov, A. V.; Milto, O. A.; Kalmykov, K. S.

2017-11-01

For the first time is proposed to combine heat flux measurements with thermal imaging and PIV (particle image velocimetry) for a comprehensive study of flow and heat transfer at the surface of the circular cooling fin. The investigated hollow fin is heated from within with saturated water steam; meanwhile the isothermal external surface simulates one of the perfect fin. Flow and heat transfer at the surface of the solid fin of the same size and shape, made of titanium alloy is investigated in the same regimes. Gradient Heat Flux Sensors (GHFS) were installed at different places of the fin surface. Velocity field around a cylinder, temperature field at the surface of the fin and heat flux for each rated time were obtained. Comprehensive method including heat flux measurement, PIV and thermal imaging allow to study flow and heat transfer at the surface of the fin in real time regime. The possibility to study flow and heat transfer for non-isothermal fins is shown; it is allow to improve traditional calculation of the cooling fins.

Digital mammographic tumor classification using transfer learning from deep convolutional neural networks.

Science.gov (United States)

Huynh, Benjamin Q; Li, Hui; Giger, Maryellen L

2016-07-01

Convolutional neural networks (CNNs) show potential for computer-aided diagnosis (CADx) by learning features directly from the image data instead of using analytically extracted features. However, CNNs are difficult to train from scratch for medical images due to small sample sizes and variations in tumor presentations. Instead, transfer learning can be used to extract tumor information from medical images via CNNs originally pretrained for nonmedical tasks, alleviating the need for large datasets. Our database includes 219 breast lesions (607 full-field digital mammographic images). We compared support vector machine classifiers based on the CNN-extracted image features and our prior computer-extracted tumor features in the task of distinguishing between benign and malignant breast lesions. Five-fold cross validation (by lesion) was conducted with the area under the receiver operating characteristic (ROC) curve as the performance metric. Results show that classifiers based on CNN-extracted features (with transfer learning) perform comparably to those using analytically extracted features [area under the ROC curve [Formula: see text

Digital X-ray Imaging in Dentistry

International Nuclear Information System (INIS)

Kim, Eun Kyung

1999-01-01

In dentistry, Radio Visio Graphy was introduced as a first electronic dental x-ray imaging modality in 1989. Thereafter, many types of direct digital radiographic systems have been produced in the last decade. They are based either on charge-coupled device (CCD) or on storage phosphor technology. In addition, new types of digital radiographic system using amorphous selenium, image intensifier etc. are under development. Advantages of digital radiographic system are elimination of chemical processing, reduction in radiation dose, image processing, computer storage, electronic transfer of images and so on. Image processing includes image enhancement, image reconstruction, digital subtraction, etc. Especially digital subtraction and reconstruction can be applied in many aspects of clinical practice and research. Electronic transfer of images enables filmless dental hospital and teleradiology/teledentistry system. Since the first image management and communications system (IMACS) for dentomaxillofacial radiology was reported in 1992, IMACS in dental hospital has been increasing. Meanwhile, researches about computer-assisted diagnosis, such as structural analysis of bone trabecular patterns of mandible, feature extraction, automated identification of normal landmarks on cephalometric radiograph and automated image analysis for caries or periodontitis, have been performed actively in the last decade. Further developments in digital radiographic imaging modalities, image transmission system, imaging processing and automated analysis software will change the traditional clinical dental practice in the 21st century.

Digital X-ray Imaging in Dentistry

Energy Technology Data Exchange (ETDEWEB)

Kim, Eun Kyung [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Dankook University, Yongin (Korea, Republic of)

1999-08-15

In dentistry, Radio Visio Graphy was introduced as a first electronic dental x-ray imaging modality in 1989. Thereafter, many types of direct digital radiographic systems have been produced in the last decade. They are based either on charge-coupled device (CCD) or on storage phosphor technology. In addition, new types of digital radiographic system using amorphous selenium, image intensifier etc. are under development. Advantages of digital radiographic system are elimination of chemical processing, reduction in radiation dose, image processing, computer storage, electronic transfer of images and so on. Image processing includes image enhancement, image reconstruction, digital subtraction, etc. Especially digital subtraction and reconstruction can be applied in many aspects of clinical practice and research. Electronic transfer of images enables filmless dental hospital and teleradiology/teledentistry system. Since the first image management and communications system (IMACS) for dentomaxillofacial radiology was reported in 1992, IMACS in dental hospital has been increasing. Meanwhile, researches about computer-assisted diagnosis, such as structural analysis of bone trabecular patterns of mandible, feature extraction, automated identification of normal landmarks on cephalometric radiograph and automated image analysis for caries or periodontitis, have been performed actively in the last decade. Further developments in digital radiographic imaging modalities, image transmission system, imaging processing and automated analysis software will change the traditional clinical dental practice in the 21st century.

Panoramic images of conventional radiographs: digital panoramic dynamic images

International Nuclear Information System (INIS)

Schultze, M.

2001-01-01

The benefits of digital technic s to od ontology are evident. Instant images, the possibility to handle them, the reduction of exposition time to radiations, better quality image, better quality information, Stocking them in a compact disc, occupying very little space, allows an easy transport and duplication, as well as the possibility to transfer and save it in an electronica l support.This kind of communication allows the transmission of digital images and every other type of data, instantaneously and no matter distances or geographical borders. Anyway, we should point out that conventional and digital technic s reveal the same information contents

Modulation Transfer Function of Infrared Focal Plane Arrays

Science.gov (United States)

Gunapala, S. D.; Rafol, S. B.; Ting, D. Z.; Soibel, A.; Hill, C. J.; Khoshakhlagh, A.; Liu, J. K.; Mumolo, J. M.; Hoglund, L.; Luong, E. M.

2015-01-01

Modulation transfer function (MTF) is the ability of an imaging system to faithfully image a given object. The MTF of an imaging system quantifies the ability of the system to resolve or transfer spatial frequencies. In this presentation we will discuss the detail MTF measurements of 1024x1024 pixels mid -wavelength and long- wavelength quantum well infrared photodetector, and 320x256 pixels long- wavelength InAs/GaSb superlattice infrared focal plane arrays (FPAs). Long wavelength Complementary Barrier Infrared Detector (CBIRD) based on InAs/GaSb superlattice material is hybridized to recently designed and fabricated 320x256 pixel format ROIC. The n-type CBIRD was characterized in terms of performance and thermal stability. The experimentally measured NE delta T of the 8.8 micron cutoff n-CBIRD FPA was 18.6 mK with 300 K background and f/2 cold stop at 78K FPA operating temperature. The horizontal and vertical MTFs of this pixel fully delineated CBIRD FPA at Nyquist frequency are 49% and 52%, respectively.

Operational parameters analysis of the radiographic technique through the modulation transfer function

International Nuclear Information System (INIS)

Motta, Mauricio Saldanha; Guimaraes, Ari Sauer

1995-01-01

The influence of the focal size and image magnification variations on the radiographic final image is studied. The analysis used the modulation transfer function for evaluating the ratio of the radiographic image amplitude and that of the inspected object. it was concluded that the increase of the focal size and of the magnifications are not good for the image quality. 3 refs., 4 figs., 1 tab

Repeated CT scans in trauma transfers: An analysis of indications, radiation dose exposure, and costs

International Nuclear Information System (INIS)

Hinzpeter, Ricarda; Sprengel, Kai; Wanner, Guido A.; Mildenberger, Peter; Alkadhi, Hatem

2017-01-01

Highlights: • Repetition of CT in trauma patients occurs relatively often. • Repetition of CT is mainly caused by inadequate image data transfer. • Potentially preventable CT examinations add radiation dose to patients. • Repeated CT is associated with excess costs to the health care system. - Abstract: Objectives: To identify the number of CT scans repeated in acute trauma patients receiving imaging before being referred to a trauma center, to define indications, and to assess radiation doses and costs of repeated CT. Methods: This retrospective study included all adult trauma patients transferred from other hospitals to a Level-I trauma center during 2014. Indications for repeated CT scans were categorized into: inadequate CT image data transfer, poor image quality, repetition of head CT after head injury together with completion to whole-body CT (WBCT), and follow-up of injury known from previous CT. Radiation doses from repeated CT were determined; costs were calculated using a nation-wide fee schedule. Results: Within one year, 85/298 (28.5%) trauma patients were transferred from another hospital because of severe head injury (n = 45,53%) and major body trauma (n = 23;27%) not manageable in the referring hospital, repatriation from a foreign country (n = 14;16.5%), and no ICU-capacity (n = 3;3.5%). Of these 85 patients, 74 (87%) had repeated CT in our center because of inadequate CT data transfer (n = 29;39%), repetition of head CT with completion to WBCT (n = 24;32.5%), and follow-up of known injury (n = 21;28.5%). None occurred because of poor image quality. Cumulative dose length product (DLP) and annual costs of potential preventable, repeated CT (inadequate data transfer) was 631mSv (81′304mGy*cm) and 35′233€, respectively. Conclusion: A considerable number of transferred trauma patients undergo potentially preventable, repeated CT, adding radiation dose to patients and costs to the health care system.

Repeated CT scans in trauma transfers: An analysis of indications, radiation dose exposure, and costs

Energy Technology Data Exchange (ETDEWEB)

Hinzpeter, Ricarda, E-mail: Ricarda.Hinzpeter@usz.ch [Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Raemistr. 100, Zurich CH-8091 (Switzerland); Sprengel, Kai, E-mail: Kai.Sprengel@usz.ch [Division of Trauma Surgery, Department of Surgery, University Hospital Zurich, University of Zurich, Raemistr. 100, CH-8091 Zurich (Switzerland); Wanner, Guido A., E-mail: Guido.Wanner@sbk-vs.de [Division of Trauma Surgery, Department of Surgery, University Hospital Zurich, University of Zurich, Raemistr. 100, CH-8091 Zurich (Switzerland); Department of General Surgery, Schwarzwald-Baar Klinikum, University of Freiburg, Klinikstr. 11, D-78052 Villingen-Schwenningen (Germany); Mildenberger, Peter, E-mail: peter.mildenberger@unimedizin-mainz.de [Department of Diagnostic and Interventional Radiology, University Hospital of Mainz, Langenbeckstr. 1, D-55131 Mainz (Germany); Alkadhi, Hatem, E-mail: hatem.alkadhi@usz.ch [Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Raemistr. 100, Zurich CH-8091 (Switzerland)

2017-03-15

Highlights: • Repetition of CT in trauma patients occurs relatively often. • Repetition of CT is mainly caused by inadequate image data transfer. • Potentially preventable CT examinations add radiation dose to patients. • Repeated CT is associated with excess costs to the health care system. - Abstract: Objectives: To identify the number of CT scans repeated in acute trauma patients receiving imaging before being referred to a trauma center, to define indications, and to assess radiation doses and costs of repeated CT. Methods: This retrospective study included all adult trauma patients transferred from other hospitals to a Level-I trauma center during 2014. Indications for repeated CT scans were categorized into: inadequate CT image data transfer, poor image quality, repetition of head CT after head injury together with completion to whole-body CT (WBCT), and follow-up of injury known from previous CT. Radiation doses from repeated CT were determined; costs were calculated using a nation-wide fee schedule. Results: Within one year, 85/298 (28.5%) trauma patients were transferred from another hospital because of severe head injury (n = 45,53%) and major body trauma (n = 23;27%) not manageable in the referring hospital, repatriation from a foreign country (n = 14;16.5%), and no ICU-capacity (n = 3;3.5%). Of these 85 patients, 74 (87%) had repeated CT in our center because of inadequate CT data transfer (n = 29;39%), repetition of head CT with completion to WBCT (n = 24;32.5%), and follow-up of known injury (n = 21;28.5%). None occurred because of poor image quality. Cumulative dose length product (DLP) and annual costs of potential preventable, repeated CT (inadequate data transfer) was 631mSv (81′304mGy*cm) and 35′233€, respectively. Conclusion: A considerable number of transferred trauma patients undergo potentially preventable, repeated CT, adding radiation dose to patients and costs to the health care system.

Imaging expression of adenoviral HSV1-tk suicide gene transfer using the nucleoside analogue FIRU

International Nuclear Information System (INIS)

Nanda, Dharmin; Jong, Marion de; Bakker, Willem; Bijster, Magda; Cox, Peter; Vogels, Ronald; Havenga, Menzo; Driesse, Maarten; Avezaat, Cees; Morin, Kevin; Naimi, Ebrahim; Knaus, Edward; Wiebe, Leonard; Smitt, Peter Sillevis

2002-01-01

Substrates for monitoring HSV1-tk gene expression include uracil and acycloguanosine derivatives.The most commonly used uracil derivative to monitor HSV1-tk gene transfer is 1-(2-fluoro-2-deoxy-β-D-arabinofuranosyl)-5-[*I]iodouracil (fialuridine; I*-FIAU), where the asterisk denotes any of the radioactive iodine isotopes that can be used. We have previously studied other nucleosides with imaging properties as good as or better than FIAU, including 1-(2-fluoro-2-deoxy-β-D-ribofuranosyl)-5-[*I]iodouracil (FIRU). The first aim of this study was to extend the biodistribution data of 123 I-labelled FIRU. Secondly, we assessed the feasibility of detecting differences in HSV1-tk gene expression levels following adenoviral gene transfer in vivo with 123 I-FIRU. 9L rat gliosarcoma cells were stably transfected with the HSV1-tk gene (9L-tk+). 123 I-FIRU was prepared by radioiodination of 1-(2-fluoro-2-deoxy-β-D-ribofuranosyl)-5-tributylstannyl uracil (FTMRSU; precursor compound) and purified using an activated Sep-Pak column. Incubation of 9L-tk+ cells and the parental 9L cells with 123 I-FIRU resulted in a 100-fold higher accumulation of radioactivity in the 9L-tk+ cells after an optimum incubation time of 4 h. NIH-bg-nu-xid mice were then inoculated subcutaneously with HSV1-tk (-) 9L cells or HSV1-tk (+) 9L-tk+ cells into both flanks. Biodistribution studies and gamma camera imaging were performed at 15 min and 1, 2, 4 and 24 h p.i. At 15 min, the tumour/muscle, tumour/blood and tumour/brain ratios were 5.2, 1.0 and 30.3 respectively. Rapid renal clearance of the tracer from the body resulted in increasing tumour/muscle, tumour/blood and tumour/brain ratios, reaching values of 32.2, 12.5 and 171.6 at 4 h p.i. A maximum specific activity of 22%ID/g tissue was reached in the 9L-tk+ tumours 4 h after 123 I-FIRU injection. Two Ad5-based adenoviral vectors containing the HSV1-tk gene were constructed: a replication-incompetent vector with the transgene in the former E1

Objective analysis of image quality of video image capture systems

Science.gov (United States)

Rowberg, Alan H.

1990-07-01

As Picture Archiving and Communication System (PACS) technology has matured, video image capture has become a common way of capturing digital images from many modalities. While digital interfaces, such as those which use the ACR/NEMA standard, will become more common in the future, and are preferred because of the accuracy of image transfer, video image capture will be the dominant method in the short term, and may continue to be used for some time because of the low cost and high speed often associated with such devices. Currently, virtually all installed systems use methods of digitizing the video signal that is produced for display on the scanner viewing console itself. A series of digital test images have been developed for display on either a GE CT9800 or a GE Signa MRI scanner. These images have been captured with each of five commercially available image capture systems, and the resultant images digitally transferred on floppy disk to a PC1286 computer containing Optimast' image analysis software. Here the images can be displayed in a comparative manner for visual evaluation, in addition to being analyzed statistically. Each of the images have been designed to support certain tests, including noise, accuracy, linearity, gray scale range, stability, slew rate, and pixel alignment. These image capture systems vary widely in these characteristics, in addition to the presence or absence of other artifacts, such as shading and moire pattern. Other accessories such as video distribution amplifiers and noise filters can also add or modify artifacts seen in the captured images, often giving unusual results. Each image is described, together with the tests which were performed using them. One image contains alternating black and white lines, each one pixel wide, after equilibration strips ten pixels wide. While some systems have a slew rate fast enough to track this correctly, others blur it to an average shade of gray, and do not resolve the lines, or give

Chemical Exchange Saturation Transfer (CEST): what is in a name and what isn’t?

Science.gov (United States)

van Zijl, Peter C.M.; Yadav, Nirbhay N.

2011-01-01

Chemical exchange saturation transfer (CEST) imaging is a relatively new MRI contrast approach in which exogenous or endogenous compounds containing either exchangeable protons or exchangeable molecules are selectively saturated and, after transfer of this saturation, detected indirectly through the water signal with enhanced sensitivity. The focus of this review is on basic MR principles underlying CEST and similarities to and differences with conventional magnetization transfer contrast (MTC). In CEST MRI, transfer of magnetization is studied in mobile compounds instead of semisolids. Similar to MTC, CEST has contributions of both chemical exchange and dipolar cross-relaxation, but the latter can often be neglected if exchange is fast. Contrary to MTC, CEST imaging requires sufficiently slow exchange on the MR time scale to allow selective irradiation of the protons of interest. As a consequence, magnetic labeling is not limited to radio-frequency saturation but can be expanded with slower frequency-selective approaches such as inversion, gradient dephasing and frequency labeling. The basic theory, design criteria, and experimental issues for exchange transfer imaging are discussed. A new classification for CEST agents based on exchange type is proposed. The potential of this young field is discussed, especially with respect to in vivo application and translation to humans. PMID:21337419

TH-C-17A-02: New Radioluminescence Strategies Based On CRET (Cerenkov Radiation Energy Transfer) for Imaging and Therapy

Energy Technology Data Exchange (ETDEWEB)

Volotskova, O; Sun, C; Pratx, G; Xing, L [Stanford University, Stanford, CA (United States)

2014-06-15

Purpose: Cerenkov photons are produced when charged particles, emitted from radionuclides, travel through a media with a speed greater than that of the light in the media. Cerenkov radiation is mostly in the UV/Blue region and, thus, readily absorbed by biological tissue. Cerenkov Radiation Energy Transfer (CRET) is a wavelength-shifting phenomenon from blue Cerenkov light to more penetrating red wavelengths. We demonstrate the feasibility of in-depth imaging of CRET light originating from radionuclides realized by down conversion of gold nanoclusters (AuNCs, a novel particle composed of few atoms of gold coated with serum proteins) in vivo. Methods: Bovine Serum Albumin, Human Serum Albumin and Transferrin conjugated gold nanoclusters were synthesized, characterized and examined for CRET. Three different clinically used radiotracers: 18F-FDG, 90Y and 99mTc were used. Optical spectrum (440–750 nm) was recorded by sensitive bioluminescence imaging system at physiological temperature. Dose dependence (activity range from 0.5 up to 800uCi) and concentration dependence (0.01 to 1uM) studies were carried out. The compound was also imaged in a xenograft mouse model. Results: Only β+ and β--emitting radionuclides (18F-FDG, 90Y) are capable of CRET; no signal was found in 99mTc (γ-emitter). The emission peak of CRET by AuNCs was found to be ∼700 nm and was ∼3 fold times of background. In vitro studies showed a linear dependency between luminescence intensity and dose and concentration. CRET by gold nanoclusters was observed in xenografted mice injected with 100uCi of 18F-FDG. Conclusion: The unique optical, transport and chemical properties of AuNCs (gold nanoclusters) make them ideal candidates for in-vivo imaging applications. Development of new molecular imaging probes will allow us to achieve substantially improved spatiotemporal resolution, sensitivity and specificity for tumor imaging and detection.

Symmetric geometric transfer matrix partial volume correction for PET imaging: principle, validation and robustness

Science.gov (United States)

Sattarivand, Mike; Kusano, Maggie; Poon, Ian; Caldwell, Curtis

2012-11-01

Limited spatial resolution of positron emission tomography (PET) often requires partial volume correction (PVC) to improve the accuracy of quantitative PET studies. Conventional region-based PVC methods use co-registered high resolution anatomical images (e.g. computed tomography (CT) or magnetic resonance images) to identify regions of interest. Spill-over between regions is accounted for by calculating regional spread functions (RSFs) in a geometric transfer matrix (GTM) framework. This paper describes a new analytically derived symmetric GTM (sGTM) method that relies on spill-over between RSFs rather than between regions. It is shown that the sGTM is mathematically equivalent to Labbe's method; however it is a region-based method rather than a voxel-based method and it avoids handling large matrices. The sGTM method was validated using two three-dimensional (3D) digital phantoms and one physical phantom. A 3D digital sphere phantom with sphere diameters ranging from 5 to 30 mm and a sphere-to-background uptake ratio of 3-to-1 was used. A 3D digital brain phantom was used with four different anatomical regions and a background region with different activities assigned to each region. A physical sphere phantom with the same geometry and uptake as the digital sphere phantom was manufactured and PET-CT images were acquired. Using these three phantoms, the performance of the sGTM method was assessed against that of the GTM method in terms of accuracy, precision, noise propagation and robustness. The robustness was assessed by applying mis-registration errors and errors in estimates of PET point spread function (PSF). In all three phantoms, the results showed that the sGTM method has accuracy similar to that of the GTM method and within 5%. However, the sGTM method showed better precision and noise propagation than the GTM method, especially for spheres smaller than 13 mm. Moreover, the sGTM method was more robust than the GTM method when mis-registration errors or

Symmetric geometric transfer matrix partial volume correction for PET imaging: principle, validation and robustness

International Nuclear Information System (INIS)

Sattarivand, Mike; Caldwell, Curtis; Kusano, Maggie; Poon, Ian

2012-01-01

Limited spatial resolution of positron emission tomography (PET) often requires partial volume correction (PVC) to improve the accuracy of quantitative PET studies. Conventional region-based PVC methods use co-registered high resolution anatomical images (e.g. computed tomography (CT) or magnetic resonance images) to identify regions of interest. Spill-over between regions is accounted for by calculating regional spread functions (RSFs) in a geometric transfer matrix (GTM) framework. This paper describes a new analytically derived symmetric GTM (sGTM) method that relies on spill-over between RSFs rather than between regions. It is shown that the sGTM is mathematically equivalent to Labbe's method; however it is a region-based method rather than a voxel-based method and it avoids handling large matrices. The sGTM method was validated using two three-dimensional (3D) digital phantoms and one physical phantom. A 3D digital sphere phantom with sphere diameters ranging from 5 to 30 mm and a sphere-to-background uptake ratio of 3-to-1 was used. A 3D digital brain phantom was used with four different anatomical regions and a background region with different activities assigned to each region. A physical sphere phantom with the same geometry and uptake as the digital sphere phantom was manufactured and PET-CT images were acquired. Using these three phantoms, the performance of the sGTM method was assessed against that of the GTM method in terms of accuracy, precision, noise propagation and robustness. The robustness was assessed by applying mis-registration errors and errors in estimates of PET point spread function (PSF). In all three phantoms, the results showed that the sGTM method has accuracy similar to that of the GTM method and within 5%. However, the sGTM method showed better precision and noise propagation than the GTM method, especially for spheres smaller than 13 mm. Moreover, the sGTM method was more robust than the GTM method when mis-registration errors or

Learning a Transferable Change Rule from a Recurrent Neural Network for Land Cover Change Detection

Directory of Open Access Journals (Sweden)

Haobo Lyu

2016-06-01

Full Text Available When exploited in remote sensing analysis, a reliable change rule with transfer ability can detect changes accurately and be applied widely. However, in practice, the complexity of land cover changes makes it difficult to use only one change rule or change feature learned from a given multi-temporal dataset to detect any other new target images without applying other learning processes. In this study, we consider the design of an efficient change rule having transferability to detect both binary and multi-class changes. The proposed method relies on an improved Long Short-Term Memory (LSTM model to acquire and record the change information of long-term sequence remote sensing data. In particular, a core memory cell is utilized to learn the change rule from the information concerning binary changes or multi-class changes. Three gates are utilized to control the input, output and update of the LSTM model for optimization. In addition, the learned rule can be applied to detect changes and transfer the change rule from one learned image to another new target multi-temporal image. In this study, binary experiments, transfer experiments and multi-class change experiments are exploited to demonstrate the superiority of our method. Three contributions of this work can be summarized as follows: (1 the proposed method can learn an effective change rule to provide reliable change information for multi-temporal images; (2 the learned change rule has good transferability for detecting changes in new target images without any extra learning process, and the new target images should have a multi-spectral distribution similar to that of the training images; and (3 to the authors’ best knowledge, this is the first time that deep learning in recurrent neural networks is exploited for change detection. In addition, under the framework of the proposed method, changes can be detected under both binary detection and multi-class change detection.

Gas transfer in a bubbly wake flow

Science.gov (United States)

Karn, A.; Gulliver, J. S.; Monson, G. M.; Ellis, C.; Arndt, R. E. A.; Hong, J.

2016-05-01

The present work reports simultaneous bubble size and gas transfer measurements in a bubbly wake flow of a hydrofoil, designed to be similar to a hydroturbine blade. Bubble size was measured by a shadow imaging technique and found to have a Sauter mean diameter of 0.9 mm for a reference case. A lower gas flow rate, greater liquid velocities, and a larger angle of attack all resulted in an increased number of small size bubbles and a reduced weighted mean bubble size. Bubble-water gas transfer is measured by the disturbed equilibrium technique. The gas transfer model of Azbel (1981) is utilized to characterize the liquid film coefficient for gas transfer, with one scaling coefficient to reflect the fact that characteristic turbulent velocity is replaced by cross-sectional mean velocity. The coefficient was found to stay constant at a particular hydrofoil configuration while it varied within a narrow range of 0.52-0.60 for different gas/water flow conditions.

Model Transport: Towards Scalable Transfer Learning on Manifolds

DEFF Research Database (Denmark)

Freifeld, Oren; Hauberg, Søren; Black, Michael J.

2014-01-01

We consider the intersection of two research fields: transfer learning and statistics on manifolds. In particular, we consider, for manifold-valued data, transfer learning of tangent-space models such as Gaussians distributions, PCA, regression, or classifiers. Though one would hope to simply use...... ordinary Rn-transfer learning ideas, the manifold structure prevents it. We overcome this by basing our method on inner-product-preserving parallel transport, a well-known tool widely used in other problems of statistics on manifolds in computer vision. At first, this straightforward idea seems to suffer...... “commutes” with learning. Consequently, our compact framework, applicable to a large class of manifolds, is not restricted by the size of either the training or test sets. We demonstrate the approach by transferring PCA and logistic-regression models of real-world data involving 3D shapes and image...

Results of a paleomagnetic survey undertaken in the Damara mobile belt, South West Africa, with special reference to the magnetisation of the uraniferous pegmatitic granites

International Nuclear Information System (INIS)

Corner, B.; Henthorn, D.I.

1978-10-01

A project study, undertaken by the Geology Division of the AEB, on the correlation between airborne magnetic and radiometric data covering a portion of the Damara Mobile Belt in South West Africa, has revealed that all the known occurrences of uranium in late- to post-tectonic leucogranite (alaskite) of the Damara orogeny are associated with negative geomagnetic anomalies. Although the uranium occurrences themselves do not display marked geomagnetic anomalies, their immediate geological environment is characterised by the negative anomalies, which are semi-regional in extent. To investigate the origin of these anomalies, the Atomic Energy Board and the Geological Survey of South Africa undertook a palaeomagnetic study of the area. Oriented cores were taken from 31 sites in the mobile belt, 18 of which were selected within the negative magnetic zones, mostly in close association with known uraniferous alaskitic granites. Palaeomagnetic evidence suggests that the negative geomagnetic anomalies are associated with a remanent magnetisation, resulting from the Damara orogenic event, whose direction is removed from the earth's present field and which has affected rocks of the Nosib Group. Absence of this stable remanent direction in rocks stratigraphically overlying the Nosib Group accounts for the distinctive geomagnetic signature, in the form of negative anomalies, of the Nosib Group. It is this signature which can be used in airborne surveys to identify rocks of the Nosib Group outcropping, or of shallow suboutcrop, in anticlinal or dome-like structures. Since the uraniferous alaskites are mostly confined stratigraphically to the Nosib Group, the negative geomagnetic anomalies form an important prospecting criterion as they may be used to delineate target areas for further exploration in areas covered by sand, scree and duricrust deposits [af

Influence of doping on transport and magnetisation properties of Bi 2212 tapes - vortex pinning; Influence du dopage sur les proprietes de transport et d`aimantation de rubans polycristallins de Bi 2212 - ancrage de vortex

Energy Technology Data Exchange (ETDEWEB)

Zani, L

1999-12-31

Bismuth-based superconductors ar now thoroughly studied and are thought to be one of the best High Critical Temperature Superconductors (HSTC) that could be industrially developed. Though their synthesis is one of the easiest to achieve, their strong anisotropy affects drastically their transport properties under magnetic field, especially in the low field regime. In order to avoid vortices motion, two main methods have been used to introduce pinning centers: irradiation defects or dissemination of non-superconducting particles. An original method of synthesis has been developed in our laboratories, alternating electrolytic depositions and heat treatments with which one can obtain Bi 2212 tapes on silver substrate. Though we have good performances at 77 K, the J{sub c} drops by a factor of 5 at 7 T for B parallel to c-axis. By including Ag, MgO and ZrO{sub 2} particles, we tried to introduce efficient pinning centers in the superconducting matrix. Some of these dopants played also a role on intergranular connectivity. By magnetisation and transport studies, we have been able to improve the situation in these two fields. (author) 195 refs.

Influence of doping on transport and magnetisation properties of Bi 2212 tapes - vortex pinning; Influence du dopage sur les proprietes de transport et d`aimantation de rubans polycristallins de Bi 2212 - ancrage de vortex

Energy Technology Data Exchange (ETDEWEB)

Zani, L

1998-12-31

Bismuth-based superconductors ar now thoroughly studied and are thought to be one of the best High Critical Temperature Superconductors (HSTC) that could be industrially developed. Though their synthesis is one of the easiest to achieve, their strong anisotropy affects drastically their transport properties under magnetic field, especially in the low field regime. In order to avoid vortices motion, two main methods have been used to introduce pinning centers: irradiation defects or dissemination of non-superconducting particles. An original method of synthesis has been developed in our laboratories, alternating electrolytic depositions and heat treatments with which one can obtain Bi 2212 tapes on silver substrate. Though we have good performances at 77 K, the J{sub c} drops by a factor of 5 at 7 T for B parallel to c-axis. By including Ag, MgO and ZrO{sub 2} particles, we tried to introduce efficient pinning centers in the superconducting matrix. Some of these dopants played also a role on intergranular connectivity. By magnetisation and transport studies, we have been able to improve the situation in these two fields. (author) 195 refs.

Grey matter volume and cortical structure in Prader-Willi syndrome compared to typically developing young adults

Directory of Open Access Journals (Sweden)

Katherine E. Manning

2018-01-01

Full Text Available Prader-Willi syndrome (PWS is a neurodevelopmental disorder of genomic imprinting, presenting with a characteristic overeating disorder, mild to moderate intellectual disability, and a variable range of social and behavioral difficulties. Consequently, widespread alterations in neural structure and developmental and maturational trajectory would be expected. To date, there have been few quantitative and systematic studies of brain morphology in PWS, although alterations of volume and of cortical organisation have been reported. This study aimed to investigate, in detail, the structure of grey matter and cortex in the brain in a sample of young adults with PWS in a well-matched case-controlled analysis. 20 young adults with PWS, aged 19–27 years, underwent multiparameter mapping magnetic resonance imaging sequences, from which measures of grey matter volume, cortical thickness and magnetisation transfer saturation, as a proxy measure of myelination, were examined. These variables were investigated in comparison to a control group of 40 typically developing young adults, matched for age and sex. A voxel-based morphometry analysis identified large and widespread bilateral clusters of both increased and decreased grey matter volume in the brain in PWS. In particular, widespread areas of increased volume encompassed parts of the prefrontal cortex, especially medially, the majority of the cingulate cortices, from anterior to posterior aspects, insula cortices, and areas of the parietal and temporal cortices. Increased volume was also reported in the caudate, putamen and thalamus. The most ventromedial prefrontal areas, in contrast, showed reduced volume, as did the parts of the medial temporal lobe, bilateral temporal poles, and a small cluster in the right lateral prefrontal cortex. Analysis of cortical structure revealed that areas of increased volume in the PWS group were largely driven by greater cortical thickness. Conversely, analysis of

Grey matter volume and cortical structure in Prader-Willi syndrome compared to typically developing young adults.

Science.gov (United States)

Manning, Katherine E; Tait, Roger; Suckling, John; Holland, Anthony J

2018-01-01

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder of genomic imprinting, presenting with a characteristic overeating disorder, mild to moderate intellectual disability, and a variable range of social and behavioral difficulties. Consequently, widespread alterations in neural structure and developmental and maturational trajectory would be expected. To date, there have been few quantitative and systematic studies of brain morphology in PWS, although alterations of volume and of cortical organisation have been reported. This study aimed to investigate, in detail, the structure of grey matter and cortex in the brain in a sample of young adults with PWS in a well-matched case-controlled analysis. 20 young adults with PWS, aged 19-27 years, underwent multiparameter mapping magnetic resonance imaging sequences, from which measures of grey matter volume, cortical thickness and magnetisation transfer saturation, as a proxy measure of myelination, were examined. These variables were investigated in comparison to a control group of 40 typically developing young adults, matched for age and sex. A voxel-based morphometry analysis identified large and widespread bilateral clusters of both increased and decreased grey matter volume in the brain in PWS. In particular, widespread areas of increased volume encompassed parts of the prefrontal cortex, especially medially, the majority of the cingulate cortices, from anterior to posterior aspects, insula cortices, and areas of the parietal and temporal cortices. Increased volume was also reported in the caudate, putamen and thalamus. The most ventromedial prefrontal areas, in contrast, showed reduced volume, as did the parts of the medial temporal lobe, bilateral temporal poles, and a small cluster in the right lateral prefrontal cortex. Analysis of cortical structure revealed that areas of increased volume in the PWS group were largely driven by greater cortical thickness. Conversely, analysis of myelin content using

Distributed deep learning networks among institutions for medical imaging.

Science.gov (United States)

Chang, Ken; Balachandar, Niranjan; Lam, Carson; Yi, Darvin; Brown, James; Beers, Andrew; Rosen, Bruce; Rubin, Daniel L; Kalpathy-Cramer, Jayashree

2018-03-29

Deep learning has become a promising approach for automated support for clinical diagnosis. When medical data samples are limited, collaboration among multiple institutions is necessary to achieve high algorithm performance. However, sharing patient data often has limitations due to technical, legal, or ethical concerns. In this study, we propose methods of distributing deep learning models as an attractive alternative to sharing patient data. We simulate the distribution of deep learning models across 4 institutions using various training heuristics and compare the results with a deep learning model trained on centrally hosted patient data. The training heuristics investigated include ensembling single institution models, single weight transfer, and cyclical weight transfer. We evaluated these approaches for image classification in 3 independent image collections (retinal fundus photos, mammography, and ImageNet). We find that cyclical weight transfer resulted in a performance that was comparable to that of centrally hosted patient data. We also found that there is an improvement in the performance of cyclical weight transfer heuristic with a high frequency of weight transfer. We show that distributing deep learning models is an effective alternative to sharing patient data. This finding has implications for any collaborative deep learning study.

From the CERN web: knowledge transfer, sustainability, CERN openlab and more

CERN Multimedia

2015-01-01

This section highlights articles, blog posts and press releases published in the CERN web environment over the past weeks. This way, you won’t miss a thing...   Previous successful Knowledge Transfer enterprises have helped to develop several useful technologies, such as these photonic crystals, which glow when high-energy charged particles pass through, and are used for medical imaging. New Knowledge Transfer website to grow CERN’s industry links 23 November – by Harriet Jarlett  CERN’s Knowledge Transfer Group has just launched a new tool to encourage CERN researchers and businesses to share their technologies, ideas and expertise. It’s hoped that by facilitating these exchanges the tool will inspire new ways to apply CERN technologies commercially, to help benefit industry and society. Continue to read…    The power station at CERN's Prévessin site. (Image: Margot Frenot/CERN). CERN an...

The fluctuation field and anomalous magnetic viscosity in commercial NdFeB alloys, AlNiCo and the bulk amorphous ferromagnets Nd{sub 60}Fe{sub 30}Al{sub 10} and Nd{sub 60}Fe{sub 20}Co{sub 10}Al{sub 10}

Energy Technology Data Exchange (ETDEWEB)

Collocott, S.J. [CSIRO Materials Science and Engineering, Lindfield, NSW 2070 (Australia)], E-mail: stephen.collocott@csiro.au; Dunlop, J.B. [CSIRO Materials Science and Engineering, Lindfield, NSW 2070 (Australia)

2008-08-15

The fluctuation field, H{sub f}, is a useful parameter for characterising any ferromagnetic material that displays hysteresis, as it is a measure of the thermally activated rate processes that govern magnetisation reversals. Anomalous magnetic viscosity, i.e. nonmonotonic behaviour of the time dependent magnetisation, where the magnetisation is seen to increase, reach a peak, and then decrease, has been observed on both the upper and lower branches of minor loops or recoil curves in some ferromagnetic materials. Parameters relevant to the Preisach model are discussed as to their usefulness in predicting anomalous magnetic viscosity in ferromagnetic materials. This is done with reference to measurements of H{sub f} and the time dependent magnetisation in commercial NdFeB alloys, AlNiCo and the bulk amorphous ferromagnets Nd{sub 60}Fe{sub 30}Al{sub 10} and Nd{sub 60}Fe{sub 20}Co{sub 10}Al{sub 10}.

TRANSFERENCE BEFORE TRANSFERENCE.

Science.gov (United States)

Bonaminio, Vincenzo

2017-10-01

This paper is predominantly a clinical presentation that describes the transmigration of one patient's transference to another, with the analyst functioning as a sort of transponder. It involves an apparently accidental episode in which there was an unconscious intersection between two patients. The author's aim is to show how transference from one case may affect transference in another, a phenomenon the author calls transference before transference. The author believes that this idea may serve as a tool for understanding the unconscious work that takes place in the clinical situation. In a clinical example, the analyst finds himself caught up in an enactment involving two patients in which he becomes the medium of what happens in session. © 2017 The Psychoanalytic Quarterly, Inc.

Age-related changes in conventional and magnetization transfer MR imaging in elderly people: comparison with neurocognitive performance

International Nuclear Information System (INIS)

Lee, Ki Yeol; Kim, Taik Kun; Park, Min Kyu; Ko, Sung Yu; Song, In Chan; Cho, Ik Hwan

2004-01-01

This study was designed to compare three different measures of the elderly human brain; the magnetization transfer ratio (MTR) histogram, the percentage of brain parenchymal volume, and the volume of T2 hyperintense areas in terms of correlations with the study subjects'neurocognitive performance. Thirty-five healthy community-dwelling elderly volunteers aged 60-82 years underwent dual fast spin-echo (FSE) imaging and magnetization transfer imaging. A semi-automated technique was used to generate the MTR histogram, the brain parenchymal volume, and the T2 lesion volume. The subjects'neurocognitive performance was assessed by using the Korean-Mini Mental State Examination (K-MMSE) and additional tests. The peak height of the MTR (PHMTR), the percentage of brain parenchymal volume (PBV), and the normalized T2 lesion volume (T2LV) were compared between the normal group. (Z score on the K-MMSE ≥ -2, n=23) and the mild cognitive impairment group (Z score on the K-MMSE < -2, N=12), and these parameters were correlated with age and various neurocognitive performance scores. The PHMTR was significantly lower in the cognitively impaired subjects than the PHMTR in the normal subjects (ρ = 0.005). The PBV scores were lower in the cognitively impaired subjects than in the normal subjects (ρ = 0.02). The T2LV scores were significantly higher in the cognitively impaired subjects (ρ = 0.01). An inverse correlation was found between the PHMTR and T2LV (r = -0.747, ρ < 0.001), and also between the PBV and T2LV (r = -0.823, ρ < 0.001). A positive correlation was observed between the PHMTR and the PBV (r = 0.846, ρ < 0.001). Scores on the various neurocognitive tests were positively correlated with the PHMTR (6 of 7 items) and the PBV (5 of 7 items), and they were negatively correlated with the T2LV (5 of 7 items). Our findings of a correlation among the PBV, the T2LV, and the PHMTR suggest that MTR histograms and the PBV and T2LV can be used as a reliable method and valid

Use of personal computer image for processing a magnetic resonance image (MRI)

International Nuclear Information System (INIS)

Yamamoto, Tetsuo; Tanaka, Hitoshi

1988-01-01

Image processing of MR imaging was attempted by using a popular personal computer as 16-bit model. The computer processed the images on a 256 x 256 matrix and 512 x 512 matrix. The softwer languages for image-processing were those of Macro-Assembler performed by (MS-DOS). The original images, acuired with an 0.5 T superconducting machine (VISTA MR 0.5 T, Picker International) were transfered to the computer by the flexible disket. Image process are the display of image to monitor, other the contrast enhancement, the unsharped mask contrast enhancement, the various filter process, the edge detections or the color histogram was obtained in 1.6 sec to 67 sec, indicating that commercialzed personal computer had ability for routine clinical purpose in MRI-processing. (author)

Spin structures in antiferromagnetic nanoparticles

DEFF Research Database (Denmark)

Brok, Erik

dependence of the magnetisation in certain nanoparticle systems, as welll bulk systems with spin canting due to defects. In accordance with this model magnetisation measurements on goethtie (a-FeOOH) nanoparticles are presented, showing a low temperature increase in the magnetisation. The spin orientation...... experimental data from unpolarised neutron diffraction. The spin orientation is found to be close to the particle plane, which is the (111) plane of the FCC structure of NiO for particles with thickness ranging from 2.2 nm to bulk (= 200 nm) particles. In the smallest particles, with a thickness of 2.0 nm, we...

31P saturation transfer and phosphocreatine imaging in the monkey brain

International Nuclear Information System (INIS)

Mora, B.; Narasimhan, P.T.; Ross, B.D.; Allman, J.; Barker, P.B.

1991-01-01

31 P magnetic resonance imaging with chemical-shift discrimination by selective excitation has been employed to determine the phosphocreatine (PCr) distribution in the brains of three juvenile macaque monkeys. PCr images were also obtained while saturating the resonance of the γ-phosphate of ATP, which allowed the investigation of the chemical exchange between PCr and the γ-phosphate of ATP catalyzed by creatine kinase. Superposition of the PCr images over the proton image of the same monkey brain revealed topological variations in the distribution of PCr and creatine kinase activity. PCr images were also obtained with and without visual stimulation. In two out of four experiments, an apparently localized decrease in PCr concentration was noted in visual cortex upon visual stimulation. This result is interpreted in terms of a possible role for the local ADP concentration in stimulating the accompanying metabolic response

Back-dropout Transfer Learning for Action Recognition

DEFF Research Database (Denmark)

Ren, Huamin; Kanhabua, Nattiya; Møgelmose, Andreas

2018-01-01

transfer learning being a promising approach, it is still an open question how to adapt the model learned from the source dataset to the target dataset. One big challenge is to prevent the impact of category bias on classification performance. Dataset bias exists when two images from the same category...

Singular value decomposition analysis of a photoacoustic imaging system and 3D imaging at 0.7 FPS.

Science.gov (United States)

Roumeliotis, Michael B; Stodilka, Robert Z; Anastasio, Mark A; Ng, Eldon; Carson, Jeffrey J L

2011-07-04

Photoacoustic imaging is a non-ionizing imaging modality that provides contrast consistent with optical imaging techniques while the resolution and penetration depth is similar to ultrasound techniques. In a previous publication [Opt. Express 18, 11406 (2010)], a technique was introduced to experimentally acquire the imaging operator for a photoacoustic imaging system. While this was an important foundation for future work, we have recently improved the experimental procedure allowing for a more densely populated imaging operator to be acquired. Subsets of the imaging operator were produced by varying the transducer count as well as the measurement space temporal sampling rate. Examination of the matrix rank and the effect of contributing object space singular vectors to image reconstruction were performed. For a PAI system collecting only limited data projections, matrix rank increased linearly with transducer count and measurement space temporal sampling rate. Image reconstruction using a regularized pseudoinverse of the imaging operator was performed on photoacoustic signals from a point source, line source, and an array of point sources derived from the imaging operator. As expected, image quality increased for each object with increasing transducer count and measurement space temporal sampling rate. Using the same approach, but on experimentally sampled photoacoustic signals from a moving point-like source, acquisition, data transfer, reconstruction and image display took 1.4 s using one laser pulse per 3D frame. With relatively simple hardware improvements to data transfer and computation speed, our current imaging results imply that acquisition and display of 3D photoacoustic images at laser repetition rates of 10Hz is easily achieved.

Image quality evaluation of medical color and monochrome displays using an imaging colorimeter

Science.gov (United States)

Roehrig, Hans; Gu, Xiliang; Fan, Jiahua

2012-10-01

The purpose of this presentation is to demonstrate the means which permit examining the accuracy of Image Quality with respect to MTF (Modulation Transfer Function) and NPS (Noise Power Spectrum) of Color Displays and Monochrome Displays. Indications were in the past that color displays could affect the clinical performance of color displays negatively compared to monochrome displays. Now colorimeters like the PM-1423 are available which have higher sensitivity and color accuracy than the traditional cameras like CCD cameras. Reference (1) was not based on measurements made with a colorimeter. This paper focuses on the measurements of physical characteristics of the spatial resolution and noise performance of color and monochrome medical displays which were made with a colorimeter and we will after this meeting submit the data to an ROC study so we have again a paper to present at a future SPIE Conference.Specifically, Modulation Transfer Function (MTF) and Noise Power Spectrum (NPS) were evaluated and compared at different digital driving levels (DDL) between the two medical displays. This paper focuses on the measurements of physical characteristics of the spatial resolution and noise performance of color and monochrome medical displays which were made with a colorimeter and we will after this meeting submit the data to an ROC study so we have again a paper to present at a future Annual SPIE Conference. Specifically, Modulation Transfer Function (MTF) and Noise Power Spectrum (NPS) were evaluated and compared at different digital driving levels (DDL) between the two medical displays. The Imaging Colorimeter. Measurement of color image quality needs were done with an imaging colorimeter as it is shown below. Imaging colorimetry is ideally suited to FPD measurement because imaging systems capture spatial data generating millions of data points in a single measurement operation. The imaging colorimeter which was used was the PM-1423 from Radiant Imaging. It uses

Imaging expression of adenoviral HSV1-tk suicide gene transfer using the nucleoside analogue FIRU

Energy Technology Data Exchange (ETDEWEB)

Nanda, Dharmin [Department of Neurology, Daniel den Hoed Cancer Centre, University Hospital Rotterdam (Netherlands); Department of Neurosurgery, University Hospital Rotterdam (Netherlands); Jong, Marion de; Bakker, Willem; Bijster, Magda; Cox, Peter [Department of Nuclear Medicine, University Hospital Rotterdam (Netherlands); Vogels, Ronald; Havenga, Menzo [Crucell Holland BV, Leiden (Netherlands); Driesse, Maarten; Avezaat, Cees [Department of Neurosurgery, University Hospital Rotterdam (Netherlands); Morin, Kevin; Naimi, Ebrahim; Knaus, Edward; Wiebe, Leonard [Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton (Canada); Smitt, Peter Sillevis [Department of Neurology, Daniel den Hoed Cancer Centre, University Hospital Rotterdam (Netherlands)

2002-07-01

Substrates for monitoring HSV1-tk gene expression include uracil and acycloguanosine derivatives.The most commonly used uracil derivative to monitor HSV1-tk gene transfer is 1-(2-fluoro-2-deoxy-{beta}-D-arabinofuranosyl)-5-[*I]iodouracil (fialuridine; I*-FIAU), where the asterisk denotes any of the radioactive iodine isotopes that can be used. We have previously studied other nucleosides with imaging properties as good as or better than FIAU, including 1-(2-fluoro-2-deoxy-{beta}-D-ribofuranosyl)-5-[*I]iodouracil (FIRU). The first aim of this study was to extend the biodistribution data of {sup 123}I-labelled FIRU. Secondly, we assessed the feasibility of detecting differences in HSV1-tk gene expression levels following adenoviral gene transfer in vivo with {sup 123}I-FIRU. 9L rat gliosarcoma cells were stably transfected with the HSV1-tk gene (9L-tk+). {sup 123}I-FIRU was prepared by radioiodination of 1-(2-fluoro-2-deoxy-{beta}-D-ribofuranosyl)-5-tributylstannyl uracil (FTMRSU; precursor compound) and purified using an activated Sep-Pak column. Incubation of 9L-tk+ cells and the parental 9L cells with {sup 123}I-FIRU resulted in a 100-fold higher accumulation of radioactivity in the 9L-tk+ cells after an optimum incubation time of 4 h. NIH-bg-nu-xid mice were then inoculated subcutaneously with HSV1-tk (-) 9L cells or HSV1-tk (+) 9L-tk+ cells into both flanks. Biodistribution studies and gamma camera imaging were performed at 15 min and 1, 2, 4 and 24 h p.i. At 15 min, the tumour/muscle, tumour/blood and tumour/brain ratios were 5.2, 1.0 and 30.3 respectively. Rapid renal clearance of the tracer from the body resulted in increasing tumour/muscle, tumour/blood and tumour/brain ratios, reaching values of 32.2, 12.5 and 171.6 at 4 h p.i. A maximum specific activity of 22%ID/g tissue was reached in the 9L-tk+ tumours 4 h after {sup 123}I-FIRU injection. Two Ad5-based adenoviral vectors containing the HSV1-tk gene were constructed: a replication-incompetent vector with

Heat transfer characteristics in a channel fitted with zigzag-cut baffles

Energy Technology Data Exchange (ETDEWEB)

Nuntadusit, Chayut; Waehayee, Makatar [Prince of Songkla University, Hat Yai (Thailand); Piya, Ibroheng [Princess of Naradhiwas University, Naradhiwas (Thailand); Eiamsa-ard, Smith [Mahanakorn University of Technology, Bangkok (Thailand)

2015-06-15

The heat transfer characteristics were experimentally investigated in a wind channel with different types of cut baffles for heat transfer augmentation. The aim of using zigzag-cut baffles is to create 3D flow structure behind the baffles instead of transverse vortex flow leading to enhance heat transfer. In this study, 4 types of baffles were examined; conventional baffle (Rectangular cross section with no cut), baffle with rectangular zigzag-cut, baffle with triangle zigzag-cut at 45 degree and at 90 degree. All of the baffles have the same height at H = 15 mm and flow blocking area. In the experiment, the row of seven baffles was attached on the inner surface of wind channel. The effects of pitch spacing length were also investigated at baffle pitch distance P/H = 4, 6 and 8 (H: Height of baffle). The experiments were performed at constant Reynolds number (Re) of 20000. The heat transfer patterns via Thermochromic liquid crystal sheet were visualized and recorded with a digital camera. The recorded images were then analyzed with image processing technique to obtain the distribution of Nusselt number. The flow characteristics pass through the baffles were also numerically studied with CFD simulation for understanding the heat transfer characteristics. The friction losses were measured to evaluate the thermal performance for each baffle. It was found that the baffle with rectangular zigzag-cut gives the best thermal performance due to heat transfer augmentation in upstream and downstream side of baffle.

Image quality transfer and applications in diffusion MRI

DEFF Research Database (Denmark)

Alexander, Daniel C.; Zikic, Darko; Ghosh, Aurobrata

2017-01-01

and the uniquely rich diffusion MRI data set from the human connectome project (HCP). Results highlight potential benefits of IQT in both brain connectivity mapping and microstructure imaging. In brain connectivity mapping, IQT reveals, from standard data sets, thin connection pathways that tractography normally...

Subwavelength dielectric nanorod chains for energy transfer in the visible range.

Science.gov (United States)

Li, Dongdong; Zhang, Jingjing; Yan, Changchun; Xu, Zhengji; Zhang, Dao Hua

2017-10-15

We report a new type of energy transfer device, formed by a dielectric nanorod array embedded in a silver slab. Such dielectric chain structures allow surface plasmon wave guiding with large propagation length and highly suppressed crosstalk between adjacent transmission channels. The simulation results show that our proposed design can be used to enhance the energy transfer along the waveguide-like dielectric nanorod chains via coupled plasmons, where the energy spreading is effectively suppressed, and superior imaging properties in terms of resolution and energy transfer distance can be achieved.

ADMultiImg: a novel missing modality transfer learning based CAD system for diagnosis of MCI due to AD using incomplete multi-modality imaging data

Science.gov (United States)

Liu, Xiaonan; Chen, Kewei; Wu, Teresa; Weidman, David; Lure, Fleming; Li, Jing

2018-02-01

Alzheimer's Disease (AD) is the most common cause of dementia and currently has no cure. Treatments targeting early stages of AD such as Mild Cognitive Impairment (MCI) may be most effective to deaccelerate AD, thus attracting increasing attention. However, MCI has substantial heterogeneity in that it can be caused by various underlying conditions, not only AD. To detect MCI due to AD, NIA-AA published updated consensus criteria in 2011, in which the use of multi-modality images was highlighted as one of the most promising methods. It is of great interest to develop a CAD system based on automatic, quantitative analysis of multi-modality images and machine learning algorithms to help physicians more adequately diagnose MCI due to AD. The challenge, however, is that multi-modality images are not universally available for many patients due to cost, access, safety, and lack of consent. We developed a novel Missing Modality Transfer Learning (MMTL) algorithm capable of utilizing whatever imaging modalities are available for an MCI patient to diagnose the patient's likelihood of MCI due to AD. Furthermore, we integrated MMTL with radiomics steps including image processing, feature extraction, and feature screening, and a post-processing for uncertainty quantification (UQ), and developed a CAD system called "ADMultiImg" to assist clinical diagnosis of MCI due to AD using multi-modality images together with patient demographic and genetic information. Tested on ADNI date, our system can generate a diagnosis with high accuracy even for patients with only partially available image modalities (AUC=0.94), and therefore may have broad clinical utility.

Improving accuracy and power with transfer learning using a meta-analytic database.

Science.gov (United States)

Schwartz, Yannick; Varoquaux, Gaël; Pallier, Christophe; Pinel, Philippe; Poline, Jean-Baptiste; Thirion, Bertrand

2012-01-01

Typical cohorts in brain imaging studies are not large enough for systematic testing of all the information contained in the images. To build testable working hypotheses, investigators thus rely on analysis of previous work, sometimes formalized in a so-called meta-analysis. In brain imaging, this approach underlies the specification of regions of interest (ROIs) that are usually selected on the basis of the coordinates of previously detected effects. In this paper, we propose to use a database of images, rather than coordinates, and frame the problem as transfer learning: learning a discriminant model on a reference task to apply it to a different but related new task. To facilitate statistical analysis of small cohorts, we use a sparse discriminant model that selects predictive voxels on the reference task and thus provides a principled procedure to define ROIs. The benefits of our approach are twofold. First it uses the reference database for prediction, i.e., to provide potential biomarkers in a clinical setting. Second it increases statistical power on the new task. We demonstrate on a set of 18 pairs of functional MRI experimental conditions that our approach gives good prediction. In addition, on a specific transfer situation involving different scanners at different locations, we show that voxel selection based on transfer learning leads to higher detection power on small cohorts.

A method for medulloblastoma tumor differentiation based on convolutional neural networks and transfer learning

Science.gov (United States)

Cruz-Roa, Angel; Arévalo, John; Judkins, Alexander; Madabhushi, Anant; González, Fabio

2015-12-01

Convolutional neural networks (CNN) have been very successful at addressing different computer vision tasks thanks to their ability to learn image representations directly from large amounts of labeled data. Features learned from a dataset can be used to represent images from a different dataset via an approach called transfer learning. In this paper we apply transfer learning to the challenging task of medulloblastoma tumor differentiation. We compare two different CNN models which were previously trained in two different domains (natural and histopathology images). The first CNN is a state-of-the-art approach in computer vision, a large and deep CNN with 16-layers, Visual Geometry Group (VGG) CNN. The second (IBCa-CNN) is a 2-layer CNN trained for invasive breast cancer tumor classification. Both CNNs are used as visual feature extractors of histopathology image regions of anaplastic and non-anaplastic medulloblastoma tumor from digitized whole-slide images. The features from the two models are used, separately, to train a softmax classifier to discriminate between anaplastic and non-anaplastic medulloblastoma image regions. Experimental results show that the transfer learning approach produce competitive results in comparison with the state of the art approaches for IBCa detection. Results also show that features extracted from the IBCa-CNN have better performance in comparison with features extracted from the VGG-CNN. The former obtains 89.8% while the latter obtains 76.6% in terms of average accuracy.

Digital transfer of non-destructive testing images

International Nuclear Information System (INIS)

Nelson, S.

1996-01-01

This paper intends to address a possible avenue to assist the Non-Destructive Testing Industry in managing and transferring results to their clients in a more efficient way. Data is sent around the globe in various forms to a multitude of destinations. The problem has been twofold in any industry: how to get the data into a communication network and, how to manage and utilize this data. There are many types of scanners which can digitize the graph which can then be displayed on a computer screen via a software programme. The one presented in this paper has been jointly developed by a Melbourne company, Compu Medics and AGFA Australia. This system can also capture a video signal from Ultrasound Units and display on the screen. The author also explore what can be done with this data. Possibilities are endless and include: sending it via satellite or land line to a remote reader, saving or archiving for future reference and utilising the data base for education

Factors influencing detail detectability in radiologic imaging

International Nuclear Information System (INIS)

Gurvich, A.M.

1985-01-01

The detectability of various details is estimated quantitatively from the essential technical parameters of the imaging system and additional influencing factors including viewing of the image. The analysis implies the formation of the input radiation distribution (contrast formation, influence of kVp). Noise, image contrast (gamma), modulation transfer function and contrast threshold of the observer are of different influence on details of different size. Thus further optimization of imaging systems and their adaption to specific imaging tasks are facilitated

Towards a framework for agent-based image analysis of remote-sensing data.

Science.gov (United States)

Hofmann, Peter; Lettmayer, Paul; Blaschke, Thomas; Belgiu, Mariana; Wegenkittl, Stefan; Graf, Roland; Lampoltshammer, Thomas Josef; Andrejchenko, Vera

2015-04-03

Object-based image analysis (OBIA) as a paradigm for analysing remotely sensed image data has in many cases led to spatially and thematically improved classification results in comparison to pixel-based approaches. Nevertheless, robust and transferable object-based solutions for automated image analysis capable of analysing sets of images or even large image archives without any human interaction are still rare. A major reason for this lack of robustness and transferability is the high complexity of image contents: Especially in very high resolution (VHR) remote-sensing data with varying imaging conditions or sensor characteristics, the variability of the objects' properties in these varying images is hardly predictable. The work described in this article builds on so-called rule sets. While earlier work has demonstrated that OBIA rule sets bear a high potential of transferability, they need to be adapted manually, or classification results need to be adjusted manually in a post-processing step. In order to automate these adaptation and adjustment procedures, we investigate the coupling, extension and integration of OBIA with the agent-based paradigm, which is exhaustively investigated in software engineering. The aims of such integration are (a) autonomously adapting rule sets and (b) image objects that can adopt and adjust themselves according to different imaging conditions and sensor characteristics. This article focuses on self-adapting image objects and therefore introduces a framework for agent-based image analysis (ABIA).

High-resolution confocal imaging of wall ingrowth deposition in plant transfer cells: Semi-quantitative analysis of phloem parenchyma transfer cell development in leaf minor veins of Arabidopsis.

Science.gov (United States)

Nguyen, Suong T T; McCurdy, David W

2015-04-23

Transfer cells (TCs) are trans-differentiated versions of existing cell types designed to facilitate enhanced membrane transport of nutrients at symplasmic/apoplasmic interfaces. This transport capacity is conferred by intricate wall ingrowths deposited secondarily on the inner face of the primary cell wall, hence promoting the potential trans-membrane flux of solutes and consequently assigning TCs as having key roles in plant growth and productivity. However, TCs are typically positioned deep within tissues and have been studied mostly by electron microscopy. Recent advances in fluorophore labelling of plant cell walls using a modified pseudo-Schiff-propidium iodide (mPS-PI) staining procedure in combination with high-resolution confocal microscopy have allowed visualization of cellular details of individual tissue layers in whole mounts, hence enabling study of tissue and cellular architecture without the need for tissue sectioning. Here we apply a simplified version of the mPS-PI procedure for confocal imaging of cellulose-enriched wall ingrowths in vascular TCs at the whole tissue level. The simplified mPS-PI staining procedure produced high-resolution three-dimensional images of individual cell types in vascular bundles and, importantly, wall ingrowths in phloem parenchyma (PP) TCs in minor veins of Arabidopsis leaves and companion cell TCs in pea. More efficient staining of tissues was obtained by replacing complex clearing procedures with a simple post-fixation bleaching step. We used this modified procedure to survey the presence of PP TCs in other tissues of Arabidopsis including cotyledons, cauline leaves and sepals. This high-resolution imaging enabled us to classify different stages of wall ingrowth development in Arabidopsis leaves, hence enabling semi-quantitative assessment of the extent of wall ingrowth deposition in PP TCs at the whole leaf level. Finally, we conducted a defoliation experiment as an example of using this approach to statistically

Multi-task transfer learning deep convolutional neural network: application to computer-aided diagnosis of breast cancer on mammograms

Science.gov (United States)

Samala, Ravi K.; Chan, Heang-Ping; Hadjiiski, Lubomir M.; Helvie, Mark A.; Cha, Kenny H.; Richter, Caleb D.

2017-12-01

Transfer learning in deep convolutional neural networks (DCNNs) is an important step in its application to medical imaging tasks. We propose a multi-task transfer learning DCNN with the aim of translating the ‘knowledge’ learned from non-medical images to medical diagnostic tasks through supervised training and increasing the generalization capabilities of DCNNs by simultaneously learning auxiliary tasks. We studied this approach in an important application: classification of malignant and benign breast masses. With Institutional Review Board (IRB) approval, digitized screen-film mammograms (SFMs) and digital mammograms (DMs) were collected from our patient files and additional SFMs were obtained from the Digital Database for Screening Mammography. The data set consisted of 2242 views with 2454 masses (1057 malignant, 1397 benign). In single-task transfer learning, the DCNN was trained and tested on SFMs. In multi-task transfer learning, SFMs and DMs were used to train the DCNN, which was then tested on SFMs. N-fold cross-validation with the training set was used for training and parameter optimization. On the independent test set, the multi-task transfer learning DCNN was found to have significantly (p  =  0.007) higher performance compared to the single-task transfer learning DCNN. This study demonstrates that multi-task transfer learning may be an effective approach for training DCNN in medical imaging applications when training samples from a single modality are limited.

Magnetic resonance described in the excitation dependent rotating frame of reference.

Science.gov (United States)

Tahayori, Bahman; Johnston, Leigh A; Mareels, Iven M Y; Farrell, Peter M

2008-01-01

An excitation dependent rotating frame of reference to observe the magnetic resonance phenomenon is introduced in this paper that, to the best of our knowledge, has not been used previously in the nuclear magnetic resonance context. The mathematical framework for this new rotating frame of reference is presented based on time scaling the Bloch equation after transformation to the classical rotating frame of reference whose transverse plane is rotating at the Larmor frequency. To this end, the Bloch equation is rewritten in terms of a magnetisation vector observed from the excitation dependent rotating frame of reference. The resultant Bloch equation is referred to as the time scaled Bloch equation. In the excitation dependent rotating frame of reference whose coordinates are rotating at the instantaneous Rabi frequency the observed magnetisation vector is a much slower signal than the true magnetisation in the rotating frame of reference. As a result the ordinary differential equation solvers have the ability to solve the time scaled version of the Bloch equation with a larger step size resulting in a smaller number of samples for solving the equation to a desired level of accuracy. The simulation results for different types of excitation are presented in this paper. This method may be used in true Bloch simulators in order to reduce the simulation time or increase the accuracy of the numerical solution. Moreover, the time scaled Bloch equation may be employed to determine the optimal excitation pattern in magnetic resonance imaging as well as designing pulses with better slice selectivity which is an active area of research in this field.

Three-dimensional optical transfer functions in the aberration-corrected scanning transmission electron microscope.

Science.gov (United States)

Jones, L; Nellist, P D

2014-05-01

In the scanning transmission electron microscope, hardware aberration correctors can now correct for the positive spherical aberration of round electron lenses. These correctors make use of nonround optics such as hexapoles or octupoles, leading to the limiting aberrations often being of a nonround type. Here we explore the effect of a number of potential limiting aberrations on the imaging performance of the scanning transmission electron microscope through their resulting optical transfer functions. In particular, the response of the optical transfer function to changes in defocus are examined, given that this is the final aberration to be tuned just before image acquisition. The resulting three-dimensional optical transfer functions also allow an assessment of the performance of a system for focal-series experiments or optical sectioning applications. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Screening of exciplex formation by distant electron transfer.

Science.gov (United States)

Fedorenko, S G; Khokhlova, S S; Burshtein, A I

2012-01-12

The excitation quenching by reversible exciplex formation, combined with irreversible but distant electron transfer, is considered by means of the integral encounter theory (IET). Assuming that the quenchers are in great excess, the set of IET equations for the excitations, free ions, and exciplexes is derived. Solving these equations gives the Laplace images of all these populations, and these are used to specify the quantum yields of the corresponding reaction products. It appears that diffusion facilitates the exciplex production and the electron transfer. On the other hand the stronger the electron transfer is, the weaker is the exciplex production. At slow diffusion the distant quenching of excitations by ionization prevents their reaching the contact where they can turn into exciplexes. This is a screening effect that is most pronounced when the ionization rate is large.

DERMAL AND MOUTHING TRANSFERS OF SURFACE RESIDUES MEASURED USING FLUORESCENCE IMAGING

Science.gov (United States)

To reduce the uncertainty associated with current estimates of children's exposure to pesticides by dermal contact and non-dietary ingestion, residue transfer data are required. Prior to conducting exhaustive studies, a screening study to develop and test methods for measuring...

Single-Molecule Interfacial Electron Transfer

Energy Technology Data Exchange (ETDEWEB)

Lu, H. Peter [Bowling Green State Univ., Bowling Green, OH (United States). Dept. of Chemistry and Center for Photochemical Sciences

2017-11-28

This project is focused on the use of single-molecule high spatial and temporal resolved techniques to study molecular dynamics in condensed phase and at interfaces, especially, the complex reaction dynamics associated with electron and energy transfer rate processes. The complexity and inhomogeneity of the interfacial ET dynamics often present a major challenge for a molecular level comprehension of the intrinsically complex systems, which calls for both higher spatial and temporal resolutions at ultimate single-molecule and single-particle sensitivities. Combined single-molecule spectroscopy and electrochemical atomic force microscopy approaches are unique for heterogeneous and complex interfacial electron transfer systems because the static and dynamic inhomogeneities can be identified and characterized by studying one molecule at a specific nanoscale surface site at a time. The goal of our project is to integrate and apply these spectroscopic imaging and topographic scanning techniques to measure the energy flow and electron flow between molecules and substrate surfaces as a function of surface site geometry and molecular structure. We have been primarily focusing on studying interfacial electron transfer under ambient condition and electrolyte solution involving both single crystal and colloidal TiO₂ and related substrates. The resulting molecular level understanding of the fundamental interfacial electron transfer processes will be important for developing efficient light harvesting systems and broadly applicable to problems in fundamental chemistry and physics. We have made significant advancement on deciphering the underlying mechanism of the complex and inhomogeneous interfacial electron transfer dynamics in dyesensitized TiO₂ nanoparticle systems that strongly involves with and regulated by molecule-surface interactions. We have studied interfacial electron transfer on TiO₂ nanoparticle surfaces by using ultrafast single

Lack of CT scanner in a rural emergency department increases inter-facility transfers: a pilot study.

Science.gov (United States)

Bergeron, Catherine; Fleet, Richard; Tounkara, Fatoumata Korika; Lavallée-Bourget, Isabelle; Turgeon-Pelchat, Catherine

2017-12-28

Rural emergency departments (EDs) are an important gateway to care for the 20% of Canadians who reside in rural areas. Less than 15% of Canadian rural EDs have access to a computed tomography (CT) scanner. We hypothesized that a significant proportion of inter-facility transfers from rural hospitals without CT scanners are for CT imaging. Our objective was to assess inter-facility transfers for CT imaging in a rural ED without a CT scanner. We selected a rural ED that offers 24/7 medical care with admission beds but no CT scanner. Descriptive statistics were collected from 2010 to 2015 on total ED visits and inter-facility transfers. Data was accessible through hospital and government databases. Between 2010 and 2014, there were respectively 13,531, 13,524, 13,827, 12,883, and 12,942 ED visits, with an average of 444 inter-facility transfers. An average of 33% (148/444) of inter-facility transfers were to a rural referral centre with a CT scan, with 84% being for CT scan. Inter-facility transfers incur costs and potential delays in patient diagnosis and management, yet current databases could not capture transfer times. Acquiring a CT scan may represent a reasonable opportunity for the selected rural hospital considering the number of required transfers.

OC ToGo: bed site image integration into OpenClinica with mobile devices

Science.gov (United States)

Haak, Daniel; Gehlen, Johan; Jonas, Stephan; Deserno, Thomas M.

2014-03-01

Imaging and image-based measurements nowadays play an essential role in controlled clinical trials, but electronic data capture (EDC) systems insufficiently support integration of captured images by mobile devices (e.g. smartphones and tablets). The web application OpenClinica has established as one of the world's leading EDC systems and is used to collect, manage and store data of clinical trials in electronic case report forms (eCRFs). In this paper, we present a mobile application for instantaneous integration of images into OpenClinica directly during examination on patient's bed site. The communication between the Android application and OpenClinica is based on the simple object access protocol (SOAP) and representational state transfer (REST) web services for metadata, and secure file transfer protocol (SFTP) for image transfer, respectively. OpenClinica's web services are used to query context information (e.g. existing studies, events and subjects) and to import data into the eCRF, as well as export of eCRF metadata and structural information. A stable image transfer is ensured and progress information (e.g. remaining time) visualized to the user. The workflow is demonstrated for a European multi-center registry, where patients with calciphylaxis disease are included. Our approach improves the EDC workflow, saves time, and reduces costs. Furthermore, data privacy is enhanced, since storage of private health data on the imaging devices becomes obsolete.

Processing Infrared Images For Fire Management Applications

Science.gov (United States)

Warren, John R.; Pratt, William K.

1981-12-01

The USDA Forest Service has used airborne infrared systems for forest fire detection and mapping for many years. The transfer of the images from plane to ground and the transposition of fire spots and perimeters to maps has been performed manually. A new system has been developed which uses digital image processing, transmission, and storage. Interactive graphics, high resolution color display, calculations, and computer model compatibility are featured in the system. Images are acquired by an IR line scanner and converted to 1024 x 1024 x 8 bit frames for transmission to the ground at a 1.544 M bit rate over a 14.7 GHZ carrier. Individual frames are received and stored, then transferred to a solid state memory to refresh the display at a conventional 30 frames per second rate. Line length and area calculations, false color assignment, X-Y scaling, and image enhancement are available. Fire spread can be calculated for display and fire perimeters plotted on maps. The performance requirements, basic system, and image processing will be described.

Pediatric digital chest imaging.

Science.gov (United States)

Tarver, R D; Cohen, M; Broderick, N J; Conces, D J

1990-01-01

The Philips Computed Radiography system performs well with pediatric portable chest radiographs, handling the throughout of a busy intensive care service 24 hours a day. Images are excellent and routinely provide a conventional (unenhanced) image and an edge-enhanced image. Radiation dose is decreased by the lowered frequency of repeat examinations and the ability of the plates to respond to a much lower dose and still provide an adequate image. The high quality and uniform density of serial PCR portable radiographs greatly enhances diagnostic content of the films. Decreased resolution has not been a problem clinically. Image manipulation and electronic transfer to remote viewing stations appear to be helpful and are currently being evaluated further. The PCR system provides a marked improvement in pediatric portable chest radiology.

Pediatric digital chest imaging

International Nuclear Information System (INIS)

Tarver, R.D.; Cohen, M.; Broderick, N.J.; Conces, D.J. Jr.

1990-01-01

The Philips Computed Radiography system performs well with pediatric portable chest radiographs, handling the throughout of a busy intensive care service 24 hours a day. Images are excellent and routinely provide a conventional (unenhanced) image and an edge-enhanced image. Radiation dose is decreased by the lowered frequency of repeat examinations and the ability of the plates to respond to a much lower dose and still provide an adequate image. The high quality and uniform density of serial PCR portable radiographs greatly enhances diagnostic content of the films. Decreased resolution has not been a problem clinically. Image manipulation and electronic transfer to remote viewing stations appear to be helpful and are currently being evaluated further. The PCR system provides a marked improvement in pediatric portable chest radiology

Cross-domain and multi-task transfer learning of deep convolutional neural network for breast cancer diagnosis in digital breast tomosynthesis

Science.gov (United States)

Samala, Ravi K.; Chan, Heang-Ping; Hadjiiski, Lubomir; Helvie, Mark A.; Richter, Caleb; Cha, Kenny

2018-02-01

We propose a cross-domain, multi-task transfer learning framework to transfer knowledge learned from non-medical images by a deep convolutional neural network (DCNN) to medical image recognition task while improving the generalization by multi-task learning of auxiliary tasks. A first stage cross-domain transfer learning was initiated from ImageNet trained DCNN to mammography trained DCNN. 19,632 regions-of-interest (ROI) from 2,454 mass lesions were collected from two imaging modalities: digitized-screen film mammography (SFM) and full-field digital mammography (DM), and split into training and test sets. In the multi-task transfer learning, the DCNN learned the mass classification task simultaneously from the training set of SFM and DM. The best transfer network for mammography was selected from three transfer networks with different number of convolutional layers frozen. The performance of single-task and multitask transfer learning on an independent SFM test set in terms of the area under the receiver operating characteristic curve (AUC) was 0.78+/-0.02 and 0.82+/-0.02, respectively. In the second stage cross-domain transfer learning, a set of 12,680 ROIs from 317 mass lesions on DBT were split into validation and independent test sets. We first studied the data requirements for the first stage mammography trained DCNN by varying the mammography training data from 1% to 100% and evaluated its learning on the DBT validation set in inference mode. We found that the entire available mammography set provided the best generalization. The DBT validation set was then used to train only the last four fully connected layers, resulting in an AUC of 0.90+/-0.04 on the independent DBT test set.

Comparison between immediate and delayed imaging after gadolinium chelate injection for detecting enhanced lesions in multiple sclerosis

International Nuclear Information System (INIS)

Alizadeh, A.; Roudbari, A.; Heidarzadeh, A.; Kouhsari, M.

2010-01-01

Magnetic resonance imaging is a noninvasive and valuable method in the diagnosis of Multiple Sclerosis. Compared with other modalities, the sensitivity of Magnetic resonance imaging for detection of the lesion increases using magnetization transfer and delayed imaging. Our aim was to compare the two methods in detecting Multiple Sclerosis lesions. Patients and Methods: In this double-blind clinical trial, twenty-one patients with the definite diagnosis of Multiple Sclerosis referred to Poursina Hospital, Rasht were included. Two radiologists evaluated all the images. First, images without contrast were conducted, then 0.1 mmol/kg contrast material (Dotarem, single dose) was injected and after 30 minutes, T1W and magnetization transfer images were obtained. Seventy-two hours later, T1W images were obtained immediately after injection of 0.2 mmol/kg contrast material (double dose). The data were analyzed using Fisher's and McNemar tests by SPSS for Windows. Results: Delayed magnetization transfer showed 44 enhanced lesions using magnetization transfer (69.84%) and 29 lesions using T1 (46.03%). In addition, the number of enhanced lesions in the delayed method were significantly more than those in the immediate method (p value=0.003). Conclusion: The use of single dose in combination with magnetization transfer and delayed images after 20-30 minutes enables us to detect more enhanced lesions.

Reproducibility, and age, body-weight and gender dependency of candidate skeletal muscle MRI outcome measures in healthy volunteers

Energy Technology Data Exchange (ETDEWEB)

Morrow, Jasper M.; Reilly, Mary M.; Hanna, Michael G. [UCL Institute of Neurology, Medical Research Council Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, London (United Kingdom); Sinclair, Christopher D.J.; Yousry, Tarek A.; Thornton, John S. [UCL Institute of Neurology, Medical Research Council Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, London (United Kingdom); UCL Institute of Neurology, Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, London (United Kingdom); Fischmann, Arne [University of Basel Hospital, Department of Radiology, Division of Diagnostic and Interventional Neuroradiology, Basel (Switzerland)

2014-07-15

Quantitative magnetic resonance imaging (MRI) can potentially meet the pressing need for objective, sensitive, reproducible outcome measures in neuromuscular disease trials. We tested, in healthy volunteers, the consistency, reliability and sensitivity to normal inter-subject variation of MRI methods targeted to lower limb muscle pathology to inform the design of practical but comprehensive MRI outcome measure protocols for use in imminent patient studies. Forty-seven healthy volunteers, age 21-81 years, were subject at 3T to three-point Dixon fat-fraction measurement, T{sub 1}-relaxometry, T{sub 2}-relaxometry and magnetisation transfer ratio (MTR) imaging at mid-thigh and mid-calf level bilaterally. Fifteen subjects underwent repeat imaging at 2 weeks. Mean between-muscle fat fraction and T{sub 2} differences were small, but significant (p < 0.001). Fat fraction and T{sub 2} correlated positively, and MTR negatively with subject age in both the thigh and calf, with similar significant correlations with weight at thigh level only (p < 0.001 to p < 0.05). Scan-rescan and inter-observer intra-class correlation coefficients ranged between 0.62-0.84 and 0.79-0.99 respectively. Quantitative lower-limb muscle MRI using readily implementable methods was sensitive enough to demonstrate inter-muscle differences (small in health), and correlations with subject age and weight. In combination with high reliability, this strongly supports the suitability of these methods to provide longitudinal outcome measures in neuromuscular disease treatment trials. (orig.)

Repetitive Imaging of Reporter Gene Expression in the Lung

Directory of Open Access Journals (Sweden)

Jean-Christophe Richard

2003-10-01

Full Text Available Positron emission tomographic imaging is emerging as a powerful technology to monitor reporter transgene expression in the lungs and other organs. However, little information is available about its usefulness for studying gene expression over time. Therefore, we infected 20 rats with a replication-deficient adenovirus containing a fusion gene encoding for a mutant Herpes simplex virus type-1 thymidine kinase and an enhanced green fluorescent protein. Five additional rats were infected with a control virus. Pulmonary gene transfer was performed via intratracheal administration of vector using a surfactant-based method. Imaging was performed 4–6 hr, and 4, 7, and 10 days after gene transfer, using 9-(4-[18F]-fluoro-3-hydroxymethylbutylguanine, an imaging substrate for the mutant kinase. Lung tracer uptake assessed with imaging was moderately but significantly increased 4–6 hr after gene transfer, was maximal after 4 days, and was no longer detectable by 10 days. The temporal pattern of transgene expression measured ex vivo with in vitro assays of thymidine kinase activity and green fluorescent protein was similar to imaging. In conclusion, positron emission tomography is a reliable new tool to evaluate the onset and duration of reporter gene expression noninvasively in the lungs of intact animals.

Sub-Angstrom microscopy through incoherent imaging and image reconstruction

International Nuclear Information System (INIS)

Pennycook, S.J.; Jesson, D.E.; Chisholm, M.F.; Ferridge, A.G.; Seddon, M.J.

1992-03-01

Z-contrast scanning transmission electron microscopy (STEM) with a high-angle annular detector breaks the coherence of the imaging process, and provides an incoherent image of a crystal projection. Even in the presence of strong dynamical diffraction, the image can be accurately described as a convolution between an object function, sharply peaked at the projected atomic sites, and the probe intensity profile. Such an image can be inverted intuitively without the need for model structures, and therefore provides the important capability to reveal unanticipated interfacial arrangements. It represents a direct image of the crystal projection, revealing the location of the atomic columns and their relative high-angle scattering power. Since no phase is associated with a peak in the object function or the contrast transfer function, extension to higher resolution is also straightforward. Image restoration techniques such as maximum entropy, in conjunction with the 1.3 Angstrom probe anticipated for a 300 kV STEM, appear to provide a simple and robust route to the achievement of sub-Angstrom resolution electron microscopy

Medical Image Tamper Detection Based on Passive Image Authentication.

Science.gov (United States)

Ulutas, Guzin; Ustubioglu, Arda; Ustubioglu, Beste; V Nabiyev, Vasif; Ulutas, Mustafa

2017-12-01

Telemedicine has gained popularity in recent years. Medical images can be transferred over the Internet to enable the telediagnosis between medical staffs and to make the patient's history accessible to medical staff from anywhere. Therefore, integrity protection of the medical image is a serious concern due to the broadcast nature of the Internet. Some watermarking techniques are proposed to control the integrity of medical images. However, they require embedding of extra information (watermark) into image before transmission. It decreases visual quality of the medical image and can cause false diagnosis. The proposed method uses passive image authentication mechanism to detect the tampered regions on medical images. Structural texture information is obtained from the medical image by using local binary pattern rotation invariant (LBPROT) to make the keypoint extraction techniques more successful. Keypoints on the texture image are obtained with scale invariant feature transform (SIFT). Tampered regions are detected by the method by matching the keypoints. The method improves the keypoint-based passive image authentication mechanism (they do not detect tampering when the smooth region is used for covering an object) by using LBPROT before keypoint extraction because smooth regions also have texture information. Experimental results show that the method detects tampered regions on the medical images even if the forged image has undergone some attacks (Gaussian blurring/additive white Gaussian noise) or the forged regions are scaled/rotated before pasting.

Infrared Imaging for Inquiry-Based Learning

Science.gov (United States)

Xie, Charles; Hazzard, Edmund

2011-01-01

Based on detecting long-wavelength infrared (IR) radiation emitted by the subject, IR imaging shows temperature distribution instantaneously and heat flow dynamically. As a picture is worth a thousand words, an IR camera has great potential in teaching heat transfer, which is otherwise invisible. The idea of using IR imaging in teaching was first…

Depth-resolved ballistic imaging in a low-depth-of-field optical Kerr gated imaging system

Energy Technology Data Exchange (ETDEWEB)

Zheng, Yipeng; Tan, Wenjiang, E-mail: tanwenjiang@mail.xjtu.edu.cn; Si, Jinhai; Ren, YuHu; Xu, Shichao; Hou, Xun [Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, School of Electronics and Information Engineering, Xi' an Jiaotong University, Xianning-xilu 28, Xi' an 710049 (China); Tong, Junyi [Departments of Applied Physics, Xi' an University of Technology, Xi' an 710048 (China)

2016-09-07

We demonstrate depth-resolved imaging in a ballistic imaging system, in which a heterodyned femtosecond optical Kerr gate is introduced to extract useful imaging photons for detecting an object hidden in turbid media and a compound lens is proposed to ensure both the depth-resolved imaging capability and the long working distance. Two objects of about 15-μm widths hidden in a polystyrene-sphere suspension have been successfully imaged with approximately 600-μm depth resolution. Modulation-transfer-function curves with the object in and away from the object plane have also been measured to confirm the depth-resolved imaging capability of the low-depth-of-field (low-DOF) ballistic imaging system. This imaging approach shows potential for application in research of the internal structure of highly scattering fuel spray.

Enlargement device of an image part contained in a video signal

International Nuclear Information System (INIS)

Bossaert, J.; Bodelet, P.; Tomietto, T.

1994-01-01

To filter a signal delivered in an interlaced manner, it is foreseen to introduce in series one filter on half frame having a pass-band transfer function in the horizontal plane and a pass-high transfer function in the vertical plane. This filter carries out on the global image signal a general pass-band transfer function. All is managed so that the central frequency of this pass-band filter fits with an elaborate image resolution. By acting so the contours of structures can be enhanced. The method applies particularly to medical radiography. 3 refs., 5 figs

ART AND SCIENCE OF IMAGE MAPS.

Science.gov (United States)

Kidwell, Richard D.; McSweeney, Joseph A.

1985-01-01

The visual image of reflected light is influenced by the complex interplay of human color discrimination, spatial relationships, surface texture, and the spectral purity of light, dyes, and pigments. Scientific theories of image processing may not always achieve acceptable results as the variety of factors, some psychological, are in part, unpredictable. Tonal relationships that affect digital image processing and the transfer functions used to transform from the continuous-tone source image to a lithographic image, may be interpreted for an insight of where art and science fuse in the production process. The application of art and science in image map production at the U. S. Geological Survey is illustrated and discussed.

Restoration of longitudinal images.

Science.gov (United States)

Hu, Y; Frieden, B R

1988-01-15

In this paper, a method of restoring longitudinal images is developed. By using the transfer function for longitudinal objects, and inverse filtering, a longitudinal image may be restored. The Fourier theory and sampling theorems for transverse images cannot be used directly in the longitudinal case. A modification and reasonable approximation are introduced. We have numerically established a necessary relationship between just-resolved longitudinal separation (after inverse filtering), noise level, and the taking conditions of object distance and lens diameter. An empirical formula is also found to well-fit the computed results. This formula may be of use for designing optical systems which are to image longitudinal details, such as in robotics or microscopy.

IMAGE QUALITY FORECASTING FOR SPACE OBJECTS

Directory of Open Access Journals (Sweden)

A. I. Altukhov

2013-05-01

Full Text Available The article deals with an approach to quality predicting of the space objects images, which can be used to plan optoelectronic systems of remote sensing satellites work programs. The proposed approach is based on evaluation of the optoelectronic equipment transfer properties and calculation of indexes images quality considering the influence of the orbital shooting conditions.

Image analysis in x-ray cinefluorography

Energy Technology Data Exchange (ETDEWEB)

Ikuse, J; Yasuhara, H; Sugimoto, H [Toshiba Corp., Kawasaki, Kanagawa (Japan)

1979-02-01

For the cinefluorographic image in the cardiovascular diagnostic system, the image quality is evaluated by means of MTF (Modulation Transfer Function), and object contrast by introducing the concept of x-ray spectrum analysis. On the basis of these results, further investigation is made of optimum X-ray exposure factors set for cinefluorography and the cardiovascular diagnostic system.

on the magnetic properties of ultra-fine zinc ferrites

NARCIS (Netherlands)

Anantharaman, M.R.; Jagatheesan, S.; Malini, K.A.; Sindhu, S.; Narayanasamy, A.; Chinnasamy, C.N.; Jacobs, J.P.; Reijne, S.; Seshan, Kulathuiyer; Smits, R.H.H.; Smits, R.H.H.; Brongersma, H.H.

1998-01-01

Zinc ferrite belongs to the class of normal spinels where it is assumed to have a cation distribution of Zn2+(Fe3+)2(O2−)4, and it is purported to be showing zero net magnetisation. However, there have been recent reports suggesting that zinc ferrite exhibits anomaly in its magnetisation. Zinc

X-ray imaging in the laser-fusion program

International Nuclear Information System (INIS)

McCall, G.H.

1977-01-01

Imaging devices which are used or planned for x-ray imaging in the laser-fusion program are discussed. Resolution criteria are explained, and a suggestion is made for using the modulation transfer function as a uniform definition of resolution for these devices

Magnets

International Nuclear Information System (INIS)

Young, I.R.

1984-01-01

A magnet pole piece for an NMR imaging magnet is made of a plurality of magnetic wires with one end of each wire held in a non-magnetic spacer, the other ends of the wires being brought to a pinch, and connected to a magnetic core. The wires may be embedded in a synthetic resin and the magnetisation and uniformity thereof can be varied by adjusting the density of the wires at the spacer which forms the pole piece. (author)

Pulsed magnetization transfer imaging with body coil transmission at 3 Tesla: feasibility and application.

Science.gov (United States)

Smith, Seth A; Farrell, Jonathan A D; Jones, Craig K; Reich, Daniel S; Calabresi, Peter A; van Zijl, Peter C M

2006-10-01

Pulsed magnetization transfer (MT) imaging has been applied to quantitatively assess brain pathology in several diseases, especially multiple sclerosis (MS). To date, however, because of the high power deposition associated with the use of short, rapidly repeating MT prepulses, clinical application has been limited to lower field strengths. The contrast-to-noise ratio (CNR) of MT is limited, and this method would greatly benefit from the use of higher magnetic fields and phased-array coil reception. However, power deposition is proportional to the square of the magnetic field and scales with coil size, and MT experiments are already close to the SAR limit at 1.5T even when smaller transmit coils are used instead of the body coil. Here we show that these seemingly great obstacles can be ameliorated by the increased T(1) of tissue water at higher field, which allows for longer maintenance of sufficiently high saturation levels while using a reduced duty cycle. This enables a fast (5-6 min) high-resolution (1.5 mm isotropic) whole-brain MT acquisition with excellent anatomical visualization of gray matter (GM) and white matter (WM) structures, and even substructures. The method is demonstrated in nine normal volunteers and five patients with relapsing remitting MS (RRMS), and the results show a clear delineation of heterogeneous lesions.

Quantification of iopamidol multi-site chemical exchange properties for ratiometric chemical exchange saturation transfer (CEST) imaging of pH

International Nuclear Information System (INIS)

Sun, Phillip Zhe; Longo, Dario Livio; Hu, Wei; Xiao, Gang; Wu, Renhua

2014-01-01

pH-sensitive chemical exchange saturation transfer (CEST) MRI holds great promise for in vivo applications. However, the CEST effect depends on not only exchange rate and hence pH, but also on the contrast agent concentration, which must be determined independently for pH quantification. Ratiometric CEST MRI normalizes the concentration effect by comparing CEST measurements of multiple labile protons to simplify pH determination. Iopamidol, a commonly used x-ray contrast agent, has been explored as a ratiometric CEST agent for imaging pH. However, iopamidol CEST properties have not been solved, determination of which is important for optimization and quantification of iopamidol pH imaging. Our study numerically solved iopamidol multi-site pH-dependent chemical exchange properties. We found that iopamidol CEST MRI is suitable for measuring pH between 6 and 7.5 despite that T 1 and T 2 measurements varied substantially with pH and concentration. The pH MRI precision decreased with pH and concentration. The standard deviation of pH determined from MRI was 0.2 and 0.4 pH unit for 40 and 20 mM iopamidol solution of pH 6, and it improved to be less than 0.1 unit for pH above 7. Moreover, we determined base-catalyzed chemical exchange for 2-hydrooxypropanamido (k sw = 1.2*10 pH−4.1 ) and amide (k sw = 1.2*10 pH−4.6 ) protons that are statistically different from each other (P < 0.01, ANCOVA), understanding of which should help guide in vivo translation of iopamidol pH imaging. (paper)

Image Transmission Studies

Science.gov (United States)

Blaine, G. James; Hill, Rexford L.; Rueter, Allen P.; Senol, Evren; Studt, James W.

1988-06-01

Radiological PACS image sizes and desired retrieval response times demand high-bandwidth communication networks. Local area network technology at speeds higher that 10 Megabits/second (IEEE 802.3) have not achieved standardization nor production volume. Our current PACS experiments are based on a three-level subnet approach using 10 Mb/s Ethernet channels. An Ethernet channel is shown to support image transfers at an average throughput of 3 Mb/s. Preliminary measurements and simulation results suggest that traffic from as many as two-to-three archives can be supported on the same channel.

Hard copies for digital medical images: an overview

Science.gov (United States)

Blume, Hartwig R.; Muka, Edward

1995-04-01

This paper is a condensed version of an invited overview on the technology of film hard-copies used in radiology. Because the overview was given to an essentially nonmedical audience, the reliance on film hard-copies in radiology is outlined in greater detail. The overview is concerned with laser image recorders generating monochrome prints on silver-halide films. The basic components of laser image recorders are sketched. The paper concentrates on the physical parameters - characteristic function, dynamic range, digitization resolution, modulation transfer function, and noise power spectrum - which define image quality and information transfer capability of the printed image. A preliminary approach is presented to compare the printed image quality with noise in the acquired image as well as with the noise of state-of- the-art cathode-ray-tube display systems. High-performance laser-image- recorder/silver-halide-film/light-box systems are well capable of reproducing acquired radiologic information. Most recently development was begun toward a display function standard for soft-copy display systems to facilitate similarity of image presentation between different soft-copy displays as well as between soft- and hard-copy displays. The standard display function is based on perceptional linearization. The standard is briefly reviewed to encourage the printer industry to adopt it, too.

X-ray images in the digital mode

International Nuclear Information System (INIS)

Buchmann, F.; Balter, S.

1981-01-01

In addition to computed tomography which presents actually the most important processing and transfer procedure of digital X-ray images, application of real time addition and substraction of X-ray images in a digital mode has found considerable interest. An estimation of the information contents of both digital and analog images is made in close relation to applications. As example of an image processing system on digital base a recently developed system for intravenous arteriography is described: the Philips-DVI. (orig.) [de

The experimental study of heat transfer around molds inside a model autoclave

Science.gov (United States)

Ghamlouch, Taleb; Roux, Stéphane; Lefèvre, Nicolas; Bailleul, Jean-Luc; Sobotka, Vincent

2018-05-01

The temperature distribution within composite parts manufactured inside autoclaves plays a key role in determining the parts quality at the end of the curing cycle. Indeed, heat transfer between the parts and the surroundings inside an autoclave is strongly coupled with the flow field around the molds and can be modeled through the convective heat transfer coefficient (HTC). The aerodynamically unsuitable geometry of the molds generates complex turbulent non-uniform flows around them accompanied with the presence of dead zones. This heterogeneity can imply non-uniform convective heat transfers leading to temperature gradients inside parts that can be prejudicial. Given this fact, the purpose of this study is to perform experimental measurements in order to describe the flow field and the convective heat transfer behavior around representative industrial molds installed inside a home-made model. A key point of our model autoclave is the ease of use of non-intrusive measuring instruments: the Particle Image Velocimetry (PIV) technique and infrared imaging camera for the study of the flow field and the heat transfer coefficient distribution around the molds respectively. The experimental measurements are then compared to computational fluid dynamics (CFD) calculations performed on the computer code ANSYS Fluent 16.0®. This investigation has revealed, as expected, a non-uniform distribution of the convective heat transfer coefficient around the molds and therefore the presence of thermal gradients which can reduce the composite parts quality during an autoclave process. A good agreement has been achieved between the experimental and the numerical results leading then to the validation of the performed numerical simulations.

Optimal Subset Selection of Time-Series MODIS Images and Sample Data Transfer with Random Forests for Supervised Classification Modelling.

Science.gov (United States)

Zhou, Fuqun; Zhang, Aining

2016-10-25

Nowadays, various time-series Earth Observation data with multiple bands are freely available, such as Moderate Resolution Imaging Spectroradiometer (MODIS) datasets including 8-day composites from NASA, and 10-day composites from the Canada Centre for Remote Sensing (CCRS). It is challenging to efficiently use these time-series MODIS datasets for long-term environmental monitoring due to their vast volume and information redundancy. This challenge will be greater when Sentinel 2-3 data become available. Another challenge that researchers face is the lack of in-situ data for supervised modelling, especially for time-series data analysis. In this study, we attempt to tackle the two important issues with a case study of land cover mapping using CCRS 10-day MODIS composites with the help of Random Forests' features: variable importance, outlier identification. The variable importance feature is used to analyze and select optimal subsets of time-series MODIS imagery for efficient land cover mapping, and the outlier identification feature is utilized for transferring sample data available from one year to an adjacent year for supervised classification modelling. The results of the case study of agricultural land cover classification at a regional scale show that using only about a half of the variables we can achieve land cover classification accuracy close to that generated using the full dataset. The proposed simple but effective solution of sample transferring could make supervised modelling possible for applications lacking sample data.

Broadband homonuclear TOCSY with amplitude and phase-modulated RF mixing schemes

International Nuclear Information System (INIS)

Kirschstein, Anika; Herbst, Christian; Riedel, Kerstin; Carella, Michela; Leppert, Joerg; Ohlenschlaeger, Oliver; Goerlach, Matthias; Ramachandran, Ramadurai

2008-01-01

We have explored the design of broadband scalar coupling mediated 13 C- 13 C and cross-relaxation suppressed 1 H- 1 H TOCSY sequences employing phase/amplitude modulated inversion pulses. Considering a variety of supercycles, pulsewidths and a RF field strength of 10 kHz, the Fourier coefficients defining the amplitude and phase modulation profiles of the 180 deg. pulses were optimised numerically so as to obtain efficient magnetisation transfer within the desired range of resonance offsets. The coherence transfer characteristics of the mixing schemes were assessed via numerical simulations and experimental measurements and were compared with commonly used sequences based on rectangular RF pulses. The efficacies of the clean 1 H- 1 H TOCSY sequences were also examined via numerical simulations for application to weakly oriented systems and sequences with efficient, broadband and clean dipolar transfer characteristics were identified. In general, the amplitude and phase modulated TOCSY sequences presented here have moderately better performance characteristics than the sequences currently employed in biomolecular NMR spectroscopy

FitSKIRT: genetic algorithms to automatically fit dusty galaxies with a Monte Carlo radiative transfer code

Science.gov (United States)

De Geyter, G.; Baes, M.; Fritz, J.; Camps, P.

2013-02-01

We present FitSKIRT, a method to efficiently fit radiative transfer models to UV/optical images of dusty galaxies. These images have the advantage that they have better spatial resolution compared to FIR/submm data. FitSKIRT uses the GAlib genetic algorithm library to optimize the output of the SKIRT Monte Carlo radiative transfer code. Genetic algorithms prove to be a valuable tool in handling the multi- dimensional search space as well as the noise induced by the random nature of the Monte Carlo radiative transfer code. FitSKIRT is tested on artificial images of a simulated edge-on spiral galaxy, where we gradually increase the number of fitted parameters. We find that we can recover all model parameters, even if all 11 model parameters are left unconstrained. Finally, we apply the FitSKIRT code to a V-band image of the edge-on spiral galaxy NGC 4013. This galaxy has been modeled previously by other authors using different combinations of radiative transfer codes and optimization methods. Given the different models and techniques and the complexity and degeneracies in the parameter space, we find reasonable agreement between the different models. We conclude that the FitSKIRT method allows comparison between different models and geometries in a quantitative manner and minimizes the need of human intervention and biasing. The high level of automation makes it an ideal tool to use on larger sets of observed data.

ATOM - an OMERO add-on for automated import of image data

Directory of Open Access Journals (Sweden)

Lipp Peter

2011-10-01

Full Text Available Abstract Background Modern microscope platforms are able to generate multiple gigabytes of image data in a single experimental session. In a routine research laboratory workflow, these data are initially stored on the local acquisition computer from which files need to be transferred to the experimenter's (remote image repository (e.g., DVDs, portable hard discs or server-based storage because of limited local data storage. Although manual solutions for this migration, such as OMERO - a client-server software for visualising and managing large amounts of image data - exist, this import process may be a time-consuming and tedious task. Findings We have developed ATOM, a Java-based and thus platform-independent add-on for OMERO enabling automated transfer of image data from a wide variety of acquisition software packages into OMERO. ATOM provides a graphical user interface and allows pre-organisation of experimental data for the transfer. Conclusions ATOM is a convenient extension of the OMERO software system. An automated interface to OMERO will be a useful tool for scientists working with file formats supported by the Bio-Formats file format library, a platform-independent library for reading the most common file formats of microscope images.

A Survey of Image Encryption Algorithms

Science.gov (United States)

Kumari, Manju; Gupta, Shailender; Sardana, Pranshul

2017-12-01

Security of data/images is one of the crucial aspects in the gigantic and still expanding domain of digital transfer. Encryption of images is one of the well known mechanisms to preserve confidentiality of images over a reliable unrestricted public media. This medium is vulnerable to attacks and hence efficient encryption algorithms are necessity for secure data transfer. Various techniques have been proposed in literature till date, each have an edge over the other, to catch-up to the ever growing need of security. This paper is an effort to compare the most popular techniques available on the basis of various performance metrics like differential, statistical and quantitative attacks analysis. To measure the efficacy, all the modern and grown-up techniques are implemented in MATLAB-2015. The results show that the chaotic schemes used in the study provide highly scrambled encrypted images having uniform histogram distribution. In addition, the encrypted images provided very less degree of correlation coefficient values in horizontal, vertical and diagonal directions, proving their resistance against statistical attacks. In addition, these schemes are able to resist differential attacks as these showed a high sensitivity for the initial conditions, i.e. pixel and key values. Finally, the schemes provide a large key spacing, hence can resist the brute force attacks, and provided a very less computational time for image encryption/decryption in comparison to other schemes available in literature.

Line-scanning tomographic optical microscope with isotropic transfer function

International Nuclear Information System (INIS)

Gajdátsy, Gábor; Dudás, László; Erdélyi, Miklós; Szabó, Gábor

2010-01-01

An imaging method and optical system, referred to as a line-scanning tomographic optical microscope (LSTOM) using a combination of line-scanning technique and CT reconstruction principle, is proposed and studied theoretically and experimentally. In our implementation a narrow focus line is scanned over the sample and the reflected light is measured in a confocal arrangement. One such scan is equivalent to a transverse projection in tomography. Repeating the scanning procedure in several directions, a number of transverse projections are recorded from which the image can be obtained using conventional CT reconstruction algorithms. The resolution of the image is independent of the spatial dimensions and structure of the applied detector; furthermore, the transfer function of the system is isotropic. The imaging performance of the implemented confocal LSTOM was compared with a point-scanning confocal microscope, based on recorded images. These images demonstrate that the resolution of the confocal LSTOM exceeds (by 15%) the resolution limit of a point-scanning confocal microscope

Artificial intelligence in fracture detection: transfer learning from deep convolutional neural networks.

Science.gov (United States)

Kim, D H; MacKinnon, T

2018-05-01

To identify the extent to which transfer learning from deep convolutional neural networks (CNNs), pre-trained on non-medical images, can be used for automated fracture detection on plain radiographs. The top layer of the Inception v3 network was re-trained using lateral wrist radiographs to produce a model for the classification of new studies as either "fracture" or "no fracture". The model was trained on a total of 11,112 images, after an eightfold data augmentation technique, from an initial set of 1,389 radiographs (695 "fracture" and 694 "no fracture"). The training data set was split 80:10:10 into training, validation, and test groups, respectively. An additional 100 wrist radiographs, comprising 50 "fracture" and 50 "no fracture" images, were used for final testing and statistical analysis. The area under the receiver operator characteristic curve (AUC) for this test was 0.954. Setting the diagnostic cut-off at a threshold designed to maximise both sensitivity and specificity resulted in values of 0.9 and 0.88, respectively. The AUC scores for this test were comparable to state-of-the-art providing proof of concept for transfer learning from CNNs in fracture detection on plain radiographs. This was achieved using only a moderate sample size. This technique is largely transferable, and therefore, has many potential applications in medical imaging, which may lead to significant improvements in workflow productivity and in clinical risk reduction. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Image fusion using MIM software via picture archiving and communication system

International Nuclear Information System (INIS)

Gu Zhaoxiang; Jiang Maosong

2001-01-01

The preliminary studies of the multimodality image registration and fusion were performed using an image fusion software and a picture archiving and communication system (PACS) to explore the methodology. Original image voluminal data were acquired with a CT scanner, MR and dual-head coincidence SPECT, respectively. The data sets from all imaging devices were queried, retrieved, transferred and accessed via DICOM PACS. The image fusion was performed at the SPECT ICON work-station, where the MIM (Medical Image Merge) fusion software was installed. The images were created by re-slicing original volume on the fly. The image volumes were aligned by translation and rotation of these view ports with respect to the original volume orientation. The transparency factor and contrast were adjusted in order that both volumes can be visualized in the merged images. The image volume data of CT, MR and nuclear medicine were transferred, accessed and loaded via PACS successfully. The perfect fused images of chest CT/ 18 F-FDG and brain MR/SPECT were obtained. These results showed that image fusion technique using PACS was feasible and practical. Further experimentation and larger validation studies were needed to explore the full potential of the clinical use

Evaluation of magnetization transfer ratios for breast tissues and breast diseases

Energy Technology Data Exchange (ETDEWEB)

Sasaki, Fumio; Murai, Hiroshi; Takeuchi, Thouru; Iwase, Takuji; Miura, Shigeto; Mastushima, Shigeru; Oosaki, Hikaru [Aichi Cancer Center, Nagoya (Japan). Hospital; Kinosada, Yasuomi

1997-03-01

To determine MTRs for normal structures and benign diseases in the breast two-dimensional magnetization transfer imaging was performed in 62 patients and in 3 young female volunteers. With regard to the MTRs of measurements in the normal breast tissues, fat tissues which is close to simple cysts in MTRs show little transfer of longitudinal magnetization. MTRs of the muscles was 15.15{+-}6.22%, which exceeded those of breast parenchyma. The breast parenchyma didn`t show the change of MTR value due to the difference of patient age and due to variable amount of fat and fibrous tissues. Breast parenchyma in the two young volunteers clearly showed biphasic change of MTR values in accordance with the menstrual cycle; little transfer value was due to hydration in the postovulatory period and high transfer value was due to dehydration in the preovulatory period. In the remaining one volunteer during lactation period, mammary parenchyma shows sever decrease in MTR, because mammary gland is loaded with massive fluid, showing a very high signal intensity on First IR and T2-weighted images. MTR values of benign breast diseases including mastopathy, fibroadenoma and phyllodes tumor had no significant difference from those of the breast parenchyma and muscle. Non-invasive ductal carcinoma was equivalent to breast parenchyma in MTR. (K.H.)

How to optimize radiological images captured from digital cameras, using the Adobe Photoshop 6.0 program.

Science.gov (United States)

Chalazonitis, A N; Koumarianos, D; Tzovara, J; Chronopoulos, P

2003-06-01

Over the past decade, the technology that permits images to be digitized and the reduction in the cost of digital equipment allows quick digital transfer of any conventional radiological film. Images then can be transferred to a personal computer, and several software programs are available that can manipulate their digital appearance. In this article, the fundamentals of digital imaging are discussed, as well as the wide variety of optional adjustments that the Adobe Photoshop 6.0 (Adobe Systems, San Jose, CA) program can offer to present radiological images with satisfactory digital imaging quality.

Transfer Learning with Convolutional Neural Networks for SAR Ship Recognition

Science.gov (United States)

Zhang, Di; Liu, Jia; Heng, Wang; Ren, Kaijun; Song, Junqiang

2018-03-01

Ship recognition is the backbone of marine surveillance systems. Recent deep learning methods, e.g. Convolutional Neural Networks (CNNs), have shown high performance for optical images. Learning CNNs, however, requires a number of annotated samples to estimate numerous model parameters, which prevents its application to Synthetic Aperture Radar (SAR) images due to the limited annotated training samples. Transfer learning has been a promising technique for applications with limited data. To this end, a novel SAR ship recognition method based on CNNs with transfer learning has been developed. In this work, we firstly start with a CNNs model that has been trained in advance on Moving and Stationary Target Acquisition and Recognition (MSTAR) database. Next, based on the knowledge gained from this image recognition task, we fine-tune the CNNs on a new task to recognize three types of ships in the OpenSARShip database. The experimental results show that our proposed approach can obviously increase the recognition rate comparing with the result of merely applying CNNs. In addition, compared to existing methods, the proposed method proves to be very competitive and can learn discriminative features directly from training data instead of requiring pre-specification or pre-selection manually.

Loss of Image in Translating Chinese Poem into English

Institute of Scientific and Technical Information of China (English)

李慧芳

2012-01-01

　　The process of translating Chinese poem into English is actually the process of the transference of image. Image is the soul of poetry. In translating the poem there often exists a phenomenon that is loss of image. So there are some questions to be discussed, such as:the definition of image, the reasons of loss of image, and the way to avoid losing image. This thesis will discuss the questions from three aspects:language difference, culture difference and factors of translator.

Bladder cancer treatment response assessment using deep learning in CT with transfer learning

Science.gov (United States)

Cha, Kenny H.; Hadjiiski, Lubomir M.; Chan, Heang-Ping; Samala, Ravi K.; Cohan, Richard H.; Caoili, Elaine M.; Paramagul, Chintana; Alva, Ajjai; Weizer, Alon Z.

2017-03-01

We are developing a CAD system for bladder cancer treatment response assessment in CT. We compared the performance of the deep-learning convolution neural network (DL-CNN) using different network sizes, and with and without transfer learning using natural scene images or regions of interest (ROIs) inside and outside the bladder. The DL-CNN was trained to identify responders (T0 disease) and non-responders to chemotherapy. ROIs were extracted from segmented lesions in pre- and post-treatment scans of a patient and paired to generate hybrid pre-post-treatment paired ROIs. The 87 lesions from 82 patients generated 104 temporal lesion pairs and 6,700 pre-post-treatment paired ROIs. Two-fold cross-validation and receiver operating characteristic analysis were performed and the area under the curve (AUC) was calculated for the DL-CNN estimates. The AUCs for prediction of T0 disease after treatment were 0.77+/-0.08 and 0.75+/-0.08, respectively, for the two partitions using DL-CNN without transfer learning and a small network, and were 0.74+/-0.07 and 0.74+/-0.08 with a large network. The AUCs were 0.73+/-0.08 and 0.62+/-0.08 with transfer learning using a small network pre-trained with bladder ROIs. The AUC values were 0.77+/-0.08 and 0.73+/-0.07 using the large network pre-trained with the same bladder ROIs. With transfer learning using the large network pretrained with the Canadian Institute for Advanced Research (CIFAR-10) data set, the AUCs were 0.72+/-0.06 and 0.64+/-0.09, respectively, for the two partitions. None of the differences in the methods reached statistical significance. Our study demonstrated the feasibility of using DL-CNN for the estimation of treatment response in CT. Transfer learning did not improve the treatment response estimation. The DL-CNN performed better when transfer learning with bladder images was used instead of natural scene images.

Mechanisms of convective and boiling heat transfer enhancement via ultrasonic vibration

International Nuclear Information System (INIS)

Kim, Yi Gu; Kim, Ho Young; Kang, Seoung Min; Kang, Byung Ha; Lee, Jin Ho

2003-01-01

This work experimentally studies the fundamental mechanisms by which the ultrasonic vibration enhances convection and pool boiling heat transfer. A thin platinum wire is used as both a heat source and a temperature sensor. A high speed video imaging system is employed to observe the behavior of cavitation and thermal bubbles. It is found that when the liquid temperature is below its boiling point, cavitation takes place due to ultrasonic vibration while cavitation disappears when the liquid reaches the boiling point. Moreover, when the gas dissolved in liquid is removed by pre-degassing, the cavitation arises only locally. Depending on the liquid temperature, heat transfer rates in convection, subcooled boiling and saturated boiling regimes are examined. In convection heat transfer regime, fully agitated cavitation is the most efficient heat transfer enhancement mechanism. Subcooled boiling is most enhanced when the local cavitation is induced after degassing. In saturated boiling regime, acoustic pressure is shown to be a dominant heat transfer enhancement mechanism

WITNESSING (ANTI-) APARTHEID : DUTCH-SOUTH-AFRICAN TRANSFERS THROUGH THE CAMERA

NARCIS (Netherlands)

Henkes, Barbara

2011-01-01

This article examines how the politics of apartheid manifested itself in networks that linked South Africa with the Netherlands. It examines the transfer of narratives, images, ideas, and political practices within a transnational kinship network, as well as through a network of political activists.

Digital image display system for emergency room

International Nuclear Information System (INIS)

Murry, R.C.; Lane, T.J.; Miax, L.S.

1989-01-01

This paper reports on a digital image display system for the emergency room (ER) in a major trauma hospital. Its objective is to reduce radiographic image delivery time to a busy ER while simultaneously providing a multimodality capability. Image storage, retrieval, and display will also be facilitated with this system. The system's backbone is a token-ring network of RISC and personal computers. The display terminals are higher- function RISC computers with 1,024 2 color or gray-scale monitors. The PCs serve as administrative terminals. Nuclear medicine, CT, MR, and digitized film images are transferred to the image display system

Radiological image data migration. Practical experience and comparison of the costs of work

International Nuclear Information System (INIS)

Maass, M.; Kosonen, M.; Kormano, M.

2001-01-01

Purpose: To identify costs deriving from data migration of obsolete digital archives by measuring the workload, and to analyse migration-associated problems. Material and Methods: Two digital archives were used (DTL and MoD) and the capacity of these archives could no longer support the needs of the Medical Imaging Centre. The entire content of the DLT archive and selected data from the MoD archive were transferred to the current higher capacity (17 TB) tape archive. The running time of work processes was measured by self-reporting, and the cost of work was calculated. Results: The transfer of 43,096 studies required 314 working hours over the course of 15 months in total. The work was partly manual, partly automatic. The percentage of non-retrievable MoD images was 35. Less than 0.2% of the DLT image transfers failed due to incorrect patient or image data. The MoD - DLT transfer cost was six times higher per study than the DLT - DLT transmission cost. Conclusion: At present, data migration may be inevitable as the amount of data increases and technology advances. The data transfer proved to be labour intensive, with high fault sensitivity regarding the MoD archive. The cost of work of data migration was 0.4% of estimated digital archiving total yearly cost. Automated data migration is preferable

Quantitative differential phase contrast imaging at high resolution with radially asymmetric illumination.

Science.gov (United States)

Lin, Yu-Zi; Huang, Kuang-Yuh; Luo, Yuan

2018-06-15

Half-circle illumination-based differential phase contrast (DPC) microscopy has been utilized to recover phase images through a pair of images along multiple axes. Recently, the half-circle based DPC using 12-axis measurements significantly provides a circularly symmetric phase transfer function to improve accuracy for more stable phase recovery. Instead of using half-circle-based DPC, we propose a new scheme of DPC under radially asymmetric illumination to achieve circularly symmetric phase transfer function and enhance the accuracy of phase recovery in a more stable and efficient fashion. We present the design, implementation, and experimental image data demonstrating the ability of our method to obtain quantitative phase images of microspheres, as well as live fibroblast cell samples.

An efficient adaptive arithmetic coding image compression technology

International Nuclear Information System (INIS)

Wang Xing-Yuan; Yun Jiao-Jiao; Zhang Yong-Lei

2011-01-01

This paper proposes an efficient lossless image compression scheme for still images based on an adaptive arithmetic coding compression algorithm. The algorithm increases the image coding compression rate and ensures the quality of the decoded image combined with the adaptive probability model and predictive coding. The use of adaptive models for each encoded image block dynamically estimates the probability of the relevant image block. The decoded image block can accurately recover the encoded image according to the code book information. We adopt an adaptive arithmetic coding algorithm for image compression that greatly improves the image compression rate. The results show that it is an effective compression technology. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Nuclear medicine image and data interchange through e-mail

Energy Technology Data Exchange (ETDEWEB)

Lyra, M; Skouroliakou, K; Perris, A; Georgossopoulos, C; Pappas, D [Radiology Department, Athens University, Athens (Greece); Stefanides, C [Pediatric Hospital, Aglaia Kyriakou, Athens (Greece)

1999-12-31

Prosperity of easy interchange in every day practice of Nuclear Medicine found its application through the INTERNET media. We use a simple and safe way to interchange images and diagnostic information between the scintigraphic acquisition and processing location and the clinical department in order to improve patient`s health care and young doctor`s education. images and patient reports are transferred and saved through dedicated software to a workstation that transforms y-camera scintigraphic images in a PC readable format. Diagnosis reports and scintigraphic images are incorporated to a database directory in hypertext form. Usual WWW connection gives the possibility of patients` examinations transfer by email attachments as well as interchange of relative comments towards both directions. Cost effective solution has been achieved using standard hard- and soft-ware. Furthermore, both educational files can be downloaded from our department ftp location, by a unique password. (authors) 7 refs., 3 figs.

Nuclear medicine image and data interchange through e-mail

International Nuclear Information System (INIS)

Lyra, M.; Skouroliakou, K.; Perris, A.; Georgossopoulos, C.; Pappas, D.; Stefanides, C.

1998-01-01

Prosperity of easy interchange in every day practice of Nuclear Medicine found its application through the INTERNET media. We use a simple and safe way to interchange images and diagnostic information between the scintigraphic acquisition and processing location and the clinical department in order to improve patient's health care and young doctor's education. images and patient reports are transferred and saved through dedicated software to a workstation that transforms y-camera scintigraphic images in a PC readable format. Diagnosis reports and scintigraphic images are incorporated to a database directory in hypertext form. Usual WWW connection gives the possibility of patients' examinations transfer by email attachments as well as interchange of relative comments towards both directions. Cost effective solution has been achieved using standard hard- and soft-ware. Furthermore, both educational files can be downloaded from our department ftp location, by a unique password. (authors)

Acquiring skill at medical image inspection: learning localized in early visual processes

Science.gov (United States)

Sowden, Paul T.; Davies, Ian R. L.; Roling, Penny; Watt, Simon J.

1997-04-01

Acquisition of the skill of medical image inspection could be due to changes in visual search processes, 'low-level' sensory learning, and higher level 'conceptual learning.' Here, we report two studies that investigate the extent to which learning in medical image inspection involves low- level learning. Early in the visual processing pathway cells are selective for direction of luminance contrast. We exploit this in the present studies by using transfer across direction of contrast as a 'marker' to indicate the level of processing at which learning occurs. In both studies twelve observers trained for four days at detecting features in x- ray images (experiment one equals discs in the Nijmegen phantom, experiment two equals micro-calcification clusters in digitized mammograms). Half the observers examined negative luminance contrast versions of the images and the remainder examined positive contrast versions. On the fifth day, observers swapped to inspect their respective opposite contrast images. In both experiments leaning occurred across sessions. In experiment one, learning did not transfer across direction of luminance contrast, while in experiment two there was only partial transfer. These findings are consistent with the contention that some of the leaning was localized early in the visual processing pathway. The implications of these results for current medical image inspection training schedules are discussed.

Image transmission studies

International Nuclear Information System (INIS)

Blaine, G.J.; Hill, R.L.; Rueter, A.P.; Senol, E.; Studt, J.W.

1988-01-01

This paper discusses radiological PACS image sizes and desired retrieval response time that demand high-bandwidth communication networks. Local area network technology at speeds higher that 10 Megabits/second (IEEE 802.3) have not achieved standardization nor production volume. The authors describe current PACS experiments based on a three-level subnet approach using 10 Mb/s Ethernet channels. An Ethernet channel is shown to support image transfers at an average throughput of 3 Mb/s. Preliminary measurements and simulation results suggest that traffic from as many as two-to-three archives can be supported on the same channel

Optical asymmetric watermarking using modified wavelet fusion and diffractive imaging

Science.gov (United States)

Mehra, Isha; Nishchal, Naveen K.

2015-05-01

In most of the existing image encryption algorithms the generated keys are in the form of a noise like distribution with a uniform distributed histogram. However, the noise like distribution is an apparent sign indicating the presence of the keys. If the keys are to be transferred through some communication channels, then this may lead to a security problem. This is because; the noise like features may easily catch people's attention and bring more attacks. To address this problem it is required to transfer the keys to some other meaningful images to disguise the attackers. The watermarking schemes are complementary to image encryption schemes. In most of the iterative encryption schemes, support constraints play an important role of the keys in order to decrypt the meaningful data. In this article, we have transferred the support constraints which are generated by axial translation of CCD camera using amplitude-, and phase- truncation approach, into different meaningful images. This has been done by developing modified fusion technique in wavelet transform domain. The second issue is, in case, the meaningful images are caught by the attacker then how to solve the copyright protection. To resolve this issue, watermark detection plays a crucial role. For this purpose, it is necessary to recover the original image using the retrieved watermarks/support constraints. To address this issue, four asymmetric keys have been generated corresponding to each watermarked image to retrieve the watermarks. For decryption, an iterative phase retrieval algorithm is applied to extract the plain-texts from corresponding retrieved watermarks.

The droplet injection system used in the rod bundle heat transfer facility

International Nuclear Information System (INIS)

Frepoli, C.; Andrew, A.J.; Hochreiter, L.E.; Cheung, F.B.

2001-01-01

The full text follows. The US Nuclear Regulatory Commission (NRC) and the Pennsylvania State University are currently funding a research program entitled ''Rod Bundle Heat Transfer'' (RBHT). The main objective of the program is to investigate heat transfer during the core reflood period of a hypothetical Large Break Loss of Coolant Accident in a typical nuclear power plant. The RBHT test facility consists of a full-length 7 x 7 rod bundle. Information gathered by the RBHT test facility will be used for improvement of the reflood heat transfer models in the NRC's thermal hydraulic codes. In particular the RBHT data will be used to improve the understanding of individual heat transfer effects to the total rod heat transfer such that compensating errors present in current Best Estimate codes can be significantly reduced. The strategy in developing the test matrix is to use a ''building block'' approach in which simpler experiments are performed first to quantify a particular heat transfer mechanism alone and then the additional complications of the full two-phase flow, reflood film boiling behavior of the test facility are added in later experiments. One of these ''simpler'' experiments will be the injection of known size and velocity liquid droplets into the main stream of superheated steam. The droplet injection system consists of small diameter tubes inserted across the bundle at a given elevation. A number of equal size holes are drilled perpendicular to the surface in a triangular pitch. Water is forced into opposite ends of the tube and ejected from the holes. The injection system was tested using a digital imaging system known as VisiSizer. This system is capable of determining the diameter and velocity of small water droplets using a laser-illuminated digital camera system (LIDCS). Imaging software analyzes the digital images in real time to determine the distributions of droplet size and velocity. Pre-test analysis using COBRA-TF have been conducted to

Interreligious transfers in the Middle Ages: the case of astrology

NARCIS (Netherlands)

von Stuckrad, K.

2008-01-01

This article describes the discipline of astrology as an example of manifold interreligious contacts and transfers in the Middle Ages. Over against an image of the Middle Ages as being predominantly Christian and striving to violently suppress science, philosophy, and astrology, it is shown that in

Significance of multiple scattering in imaging through turbid media

International Nuclear Information System (INIS)

Zardecki, A.; Gerstl, S.A.W.

1986-01-01

The degradation of image quality in a turbid medium is analyzed within the framework of the small-angle approximation, the diffusion approximation, and a rigorous two-dimensional radiative transfer equation. These three approaches allow us to emphasize different aspects of the imaging problem when multiple scattering effects are important. For a medium with a forward-peaked phase function, the separation of multiple scattering into a series of scatterings of various order provides a fruitful technique. The use of the diffusion approximation and transport theory extends the determination of the modulation transfer function to a turbid medium with an arbitrary degree of anisotropy

Dynamic CT perfusion image data compression for efficient parallel processing.

Science.gov (United States)

Barros, Renan Sales; Olabarriaga, Silvia Delgado; Borst, Jordi; van Walderveen, Marianne A A; Posthuma, Jorrit S; Streekstra, Geert J; van Herk, Marcel; Majoie, Charles B L M; Marquering, Henk A

2016-03-01

The increasing size of medical imaging data, in particular time series such as CT perfusion (CTP), requires new and fast approaches to deliver timely results for acute care. Cloud architectures based on graphics processing units (GPUs) can provide the processing capacity required for delivering fast results. However, the size of CTP datasets makes transfers to cloud infrastructures time-consuming and therefore not suitable in acute situations. To reduce this transfer time, this work proposes a fast and lossless compression algorithm for CTP data. The algorithm exploits redundancies in the temporal dimension and keeps random read-only access to the image elements directly from the compressed data on the GPU. To the best of our knowledge, this is the first work to present a GPU-ready method for medical image compression with random access to the image elements from the compressed data.

Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction

KAUST Repository

Sun, Tiancheng; Peng, Yifan; Heidrich, Wolfgang

2017-01-01

Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.

Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction

KAUST Repository

Sun, Tiancheng

2017-12-25

Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.

Image quality in mammography

International Nuclear Information System (INIS)

Haus, A.G.; Doi, K.; Metz, C.E.; Bernstein, J.

1976-01-01

In mammography, image quality is a function of the shape, size, and x-ray absorption properties of the anatomic part to be radiographed and of the lesion to be detected; it also depends on geometric unsharpness, and the resolution, characteristic curve and noise properties of the recording system. X-ray energy spectra, modulation transfer functions, Wiener spectra, characteristic and gradient curves, and radiographs of a breast phantom and of a resected breast specimen containing microcalcifications are used in a review of some current considerations of the factors, and the complex relationship among factors, that affect image quality in mammography. Image quality and patient radiation exposure in mammography are interrelated. An approach to the problem of evaluating the trade-off between diagnostic certainty and the cost or risk of performing a breast imaging procedure is discussed

Plasmon-enhanced energy transfer for improved upconversion of infrared radiation in doped-lanthanide nanocrystals

Science.gov (United States)

Sun, Qi; Mundoor, Haridas; Ribot, Josep; Singh, Vivek; Smalyukh, Ivan; Nagpal, Prashant

2014-03-01

Upconversion of infrared radiation into visible light has been investigated for applications in biological imaging and photovoltaics. However, low conversion efficiency due to small absorption cross-section for infrared light (Yb3+) , and slow rate of energy transfer (to Er3+ states) has prevented application of upconversion photoluminescence (UPL) for diffuse sunlight or imaging tissue samples. Here, we utilize resonant surface plasmon polaritons (SPP) waves to enhance UPL in doped-lanthanide nanocrystals. Our analysis indicates that SPP waves not only enhance the electromagnetic field, and hence weak Purcell effect, but also increases the rate of resonant energy transfer from Yb3+ to Er3+ ions by 6 fold. While we do observe strong metal mediated quenching (14 fold) of green fluorescence on flat metal surfaces, the nanostructured metal is resonant in the infrared, and hence enhances the nanocrystal UPL. This strong columbic effect on energy transfer can have important implications for other fluorescent and excitonic systems too.

Plasmon-enhanced energy transfer for improved upconversion of infrared radiation in doped-lanthanide nanocrystals.

Science.gov (United States)

Sun, Qi-C; Mundoor, Haridas; Ribot, Josep C; Singh, Vivek; Smalyukh, Ivan I; Nagpal, Prashant

2014-01-08

Upconversion of infrared radiation into visible light has been investigated for applications in photovoltaics and biological imaging. However, low conversion efficiency due to small absorption cross-section for infrared light (Yb(3+)), and slow rate of energy transfer (to Er(3+) states) has prevented application of upconversion photoluminescence (UPL) for diffuse sunlight or imaging tissue samples. Here, we utilize resonant surface plasmon polaritons (SPP) waves to enhance UPL in doped-lanthanide nanocrystals. Our analysis indicates that SPP waves not only enhance the electromagnetic field, and hence weak Purcell effect, but also increase the rate of resonant energy transfer from Yb(3+) to Er(3+) ions by 6 fold. While we do observe strong metal mediated quenching (14-fold) of green fluorescence on flat metal surfaces, the nanostructured metal is resonant in the infrared and hence enhances the nanocrystal UPL. This strong Coulombic effect on energy transfer can have important implications for other fluorescent and excitonic systems too.

Enhanced phase contrast transfer using ptychography combined with a pre-specimen phase plate in a scanning transmission electron microscope

Energy Technology Data Exchange (ETDEWEB)

Yang, Hao; Ercius, Peter [Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Nellist, Peter D. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Ophus, Colin, E-mail: clophus@lbl.gov [Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2016-12-15

The ability to image light elements in both crystalline and noncrystalline materials at near atomic resolution with an enhanced contrast is highly advantageous to understand the structure and properties of a wide range of beam sensitive materials including biological specimens and molecular hetero-structures. This requires the imaging system to have an efficient phase contrast transfer at both low and high spatial frequencies. In this work we introduce a new phase contrast imaging method in a scanning transmission electron microscope (STEM) using a pre-specimen phase plate in the probe forming aperture, combined with a fast pixelated detector to record diffraction patterns at every probe position, and phase reconstruction using ptychography. The phase plate significantly enhances the contrast transfer of low spatial frequency information, and ptychography maximizes the extraction of the phase information at all spatial frequencies. In addition, the STEM probe with the presence of the phase plate retains its atomic resolution, allowing simultaneous incoherent Z-contrast imaging to be obtained along with the ptychographic phase image. An experimental image of Au nanoparticles on a carbon support shows high contrast for both materials. Multislice image simulations of a DNA molecule shows the capability of imaging soft matter at low dose conditions, which implies potential applications of low dose imaging of a wide range of beam sensitive materials. - Highlights: • This work demonstrates a phase contrast imaging method by combining a pre-specimen phase plate with ptychogrpahy. • This method is shown to have a high phase contrast transfer efficiency at both low and high spatial frequencies. • Unlike CTEM which uses a heavy defocus to gain contrast, the phase plate gives a linear phase contrast at zero defocus aberrations. • Image simulations of DNA suggest this method is highly attractive for imaging beam sensitive materials at a low dose.

Image quality (IQ) guided multispectral image compression

Science.gov (United States)

Zheng, Yufeng; Chen, Genshe; Wang, Zhonghai; Blasch, Erik

2016-05-01

Image compression is necessary for data transportation, which saves both transferring time and storage space. In this paper, we focus on our discussion on lossy compression. There are many standard image formats and corresponding compression algorithms, for examples, JPEG (DCT -- discrete cosine transform), JPEG 2000 (DWT -- discrete wavelet transform), BPG (better portable graphics) and TIFF (LZW -- Lempel-Ziv-Welch). The image quality (IQ) of decompressed image will be measured by numerical metrics such as root mean square error (RMSE), peak signal-to-noise ratio (PSNR), and structural Similarity (SSIM) Index. Given an image and a specified IQ, we will investigate how to select a compression method and its parameters to achieve an expected compression. Our scenario consists of 3 steps. The first step is to compress a set of interested images by varying parameters and compute their IQs for each compression method. The second step is to create several regression models per compression method after analyzing the IQ-measurement versus compression-parameter from a number of compressed images. The third step is to compress the given image with the specified IQ using the selected compression method (JPEG, JPEG2000, BPG, or TIFF) according to the regressed models. The IQ may be specified by a compression ratio (e.g., 100), then we will select the compression method of the highest IQ (SSIM, or PSNR). Or the IQ may be specified by a IQ metric (e.g., SSIM = 0.8, or PSNR = 50), then we will select the compression method of the highest compression ratio. Our experiments tested on thermal (long-wave infrared) images (in gray scales) showed very promising results.

Map Classification In Image Data

Science.gov (United States)

2015-09-25

showing the signicant portion of image and video data transfers via Youtube , Facebook, and Flickr as primary platforms from Infographic (2015) digital...reserves • hydrography: lakes, rivers, streams, swamps, coastal flats • relief: mountains, valleys, slopes, depressions • vegetation: wooded and cleared

Optimal steel thickness combined with computed radiography for portal imaging of nasopharyngeal cancer patients

International Nuclear Information System (INIS)

Wu Shixiu; Jin Xiance; Xie Congying; Cao Guoquan

2005-01-01

The poor image quality of conventional metal screen-film portal imaging system has long been of concern, and various methods have been investigated in an attempt to enhance the quality of portal images. Computed radiography (CR) used in combination with a steel plate displays image enhancement. The optimal thickness of the steel plate had been studied by measuring the modulation transfer function (MTF) characteristics. Portal images of nasopharyngeal carcinoma patients were taken by both a conventional metal screen-film system and this optimal steel and CR plate combination system. Compared with a conventional metal screen-film system, the CR-metal screen system achieves a much higher image contrast. The measured modulation transfer function (MTF) of the CR combination is greater than conventional film-screen portal imaging systems and also results in superior image performance, as demonstrated by receiver operator characteristic (ROC) analysis. This optimal combination steel CR plate portal imaging system is capable of producing high contrast portal images conveniently

Transference of surface markers in X-ray, CT- and MR-imaging

International Nuclear Information System (INIS)

Grevelhoerster, T.; Poetter, R.; Prott, F.J.; Dittrich, M.

1995-01-01

By using pharmacological capsules and plastic tubes filled with oily contrast medium contraining iodine (Lipiodol; Byk Gulden), marking aids were developed which can be seen in similar definite limits within the framework of MRI-, CT- and conventional X-ray-Imaging. A method to view these new, artificial markers in combination with individual, anatomical landmarks is introduced. The marking aid/surface marker, fixed on anatomical reference structures on the skin, does not result in an additional burden for the patient. The new, artificial markers are also useful for making other structures recognizable, such as anatomical relation lines, center of the portal and edges in planning imaging for radiotherapy treatments and are used as leading and reference structures to compare localisation and extent of lesions in X-ray-, CT- and MRI. Marking aids/surface markers do not have to be changed in different imaging methods. (orig./MG) [de

Angular dependence of switching behaviour in template released isolated NiFe nanowires

Science.gov (United States)

Sultan, Musaab Salman

2017-12-01

In this article, the magnetisation behaviour and magnetisation reversal process of both single and bundles of 3 and 7 closely-packed template released Ni60Fe40 nanowires were investigated using high-sensitivity Magneto-Optical Kerr Effect (MOKE) magnetometry. The nanowires were deposited from a dilute suspension onto gold pre-patterned silicon substrates. They were typically 9 μm in length with a diameter of approximately 200 nm. By increasing the number of clumped wires a reduction in the switching field was observed, suggesting that overall the bundle behaves like a single system and decreasing the effective external field required to switch the magnetisation. Square hysteresis loops with a sharp jump in the Kerr signal were seen for all MOKE measurement angles. This result may reflect the surface magnetisation of the nanowire, compared to their bulk behaviour as compared with the literature that adopted the same and different investigative techniques on comparable compositions and dimensions of wires. The influence of applying the magnetic field at different angles with respect to the long axis of the nanowire on the switching behaviour was analysed and compared with the theoretical calculations of non-uniform rotation of the curling model of domain reversal. An agreement and disagreement with this model was seen, respectively, for low and high angles, indicating the complexity of the magnetic state of such isolated nanowires. To confirm the results presented here, further studies are recommended using a combination of techniques sensitive to surface and bulk magnetisation on similar isolated ferromagnetic nanowires.

A kind of video image digitizing circuit based on computer parallel port

International Nuclear Information System (INIS)

Wang Yi; Tang Le; Cheng Jianping; Li Yuanjing; Zhang Binquan

2003-01-01

A kind of video images digitizing circuit based on parallel port was developed to digitize the flash x ray images in our Multi-Channel Digital Flash X ray Imaging System. The circuit can digitize the video images and store in static memory. The digital images can be transferred to computer through parallel port and can be displayed, processed and stored. (authors)

Medical Imaging Image Quality Assessment with Monte Carlo Methods

International Nuclear Information System (INIS)

Michail, C M; Fountos, G P; Kalyvas, N I; Valais, I G; Kandarakis, I S; Karpetas, G E; Martini, Niki; Koukou, Vaia

2015-01-01

The aim of the present study was to assess image quality of PET scanners through a thin layer chromatography (TLC) plane source. The source was simulated using a previously validated Monte Carlo model. The model was developed by using the GATE MC package and reconstructed images obtained with the STIR software for tomographic image reconstruction, with cluster computing. The PET scanner simulated in this study was the GE DiscoveryST. A plane source consisted of a TLC plate, was simulated by a layer of silica gel on aluminum (Al) foil substrates, immersed in 18F-FDG bath solution (1MBq). Image quality was assessed in terms of the Modulation Transfer Function (MTF). MTF curves were estimated from transverse reconstructed images of the plane source. Images were reconstructed by the maximum likelihood estimation (MLE)-OSMAPOSL algorithm. OSMAPOSL reconstruction was assessed by using various subsets (3 to 21) and iterations (1 to 20), as well as by using various beta (hyper) parameter values. MTF values were found to increase up to the 12th iteration whereas remain almost constant thereafter. MTF improves by using lower beta values. The simulated PET evaluation method based on the TLC plane source can be also useful in research for the further development of PET and SPECT scanners though GATE simulations. (paper)

Micro-PIXE evaluation of radioactive cesium transfer in contaminated soil samples

International Nuclear Information System (INIS)

Fujishiro, F.; Ishii, K.; Matsuyama, S.; Arai, H.; Ishizaki, A.; Osada, N.; Sugai, H.; Kusano, K.; Nozawa, Y.; Yamauchi, S.; Karahashi, M.; Oshikawa, S.; Kikuchi, K.; Koshio, S.; Watanabe, K.; Suzuki, Y.

2014-01-01

Highlights: • There are radioactively contaminated soils having a radioactive cesium transfer of 0.01. • Micro-PIXE analysis has revealed an existence of phosphorus in a contaminated soil. • Radioactive cesium captured by phosphorus compound would be due to radioactive transfer. -- Abstract: Micro-PIXE analysis has been performed on two soil samples with high cesium activity concentrations. These soil samples were contaminated by fallout from the accident at Fukushima Daiichi Nuclear Power Plant. One exhibits a radioactive cesium transfer of ∼0.01, and the other shows a radioactive cesium transfer of less than 0.001, even though both samples have high cesium activity concentrations exceeding 10,000 Bq/kg. X-ray spectra and elemental images of the soil samples revealed the presence of chlorine, which can react with cesium to produce an inorganic soluble compound, and phosphorus-containing cesium-capturable organic compounds

Characterization of Japanese standards for myocardial sympathetic and metabolic imaging in comparison with perfusion imaging

International Nuclear Information System (INIS)

Matsuo, Shinro; Nakajima, Kenichi; Okuda, Koichi; Yamashina, Shohei; Sakata, Kazuyuki; Momose, Mitsuru; Hashimoto, Jun; Kumita, Shinichiro; Kawano, Masaya

2009-01-01

The standard patterns of myocardial radiotracer distribution of 123 I-metaiodobenzylguanidine (MIBG) and 123 I-β-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) should be defined in a Japanese population. The purpose of this study was to present and provide data on the characteristics of MIBG and BMIPP with respect to myocardial single photon emission computed tomography. The normal database included 123 I-MIBG and 123 I-BMIPP imaging and a 99 mTc-sestamibi/tetrofosmin myocardial perfusion study. The projection images were transferred by digital imaging and communications in medicine (DICOM) format and reconstructed and analyzed with polar maps. The projection data from multiple centers were successfully transferred to a common format for single photon emission computed tomography (SPECT) reconstruction. When the average values were analyzed using a 17-segment model, MIBG uptake in the inferior and apical wall appeared to be slightly lower than anterior uptake (P 99m Tc-tracer uptake (P<0.05). Myocardial sympathetic nerve and metabolic scintigraphy data that were specific for the Japanese population were generated and found to be different from that of perfusion tracers. The normal database can serve as a standard for nuclear cardiology work conducted in Japan. (author)

Classifying images using restricted Boltzmann machines and convolutional neural networks

Science.gov (United States)

Zhao, Zhijun; Xu, Tongde; Dai, Chenyu

2017-07-01

To improve the feature recognition ability of deep model transfer learning, we propose a hybrid deep transfer learning method for image classification based on restricted Boltzmann machines (RBM) and convolutional neural networks (CNNs). It integrates learning abilities of two models, which conducts subject classification by exacting structural higher-order statistics features of images. While the method transfers the trained convolutional neural networks to the target datasets, fully-connected layers can be replaced by restricted Boltzmann machine layers; then the restricted Boltzmann machine layers and Softmax classifier are retrained, and BP neural network can be used to fine-tuned the hybrid model. The restricted Boltzmann machine layers has not only fully integrated the whole feature maps, but also learns the statistical features of target datasets in the view of the biggest logarithmic likelihood, thus removing the effects caused by the content differences between datasets. The experimental results show that the proposed method has improved the accuracy of image classification, outperforming other methods on Pascal VOC2007 and Caltech101 datasets.

High-energy laser-assisted imaging through vaporizing aerosols

International Nuclear Information System (INIS)

Zardecki, A.; Gerstl, S.A.W.

1988-02-01

The degradation of image quality due to multiple scattering in a turbid medium is analyzed various conditions of illumination. The emphasis is on the forward-peaked multiple scattering effects, which can adequately be described by the small-angle approximation. In the case of incoherent illumination, the modulation transfer function (MTF) can be given explicity both in the low- and high-frequency limits. For scattering with smaller degree of anisotropy, the MTF should be imputed numerically by considering numerical by considering solutions to the equation of radiative transfer with a line or point source. As the beam power increases, the turbid medium becomes modified by its interactions with the beam, thus affecting the image resolution. In this nonlinear transport regime (flux levels of the order of 10 6 Wcm 2 and higher) the propagation leads actually to beam narrowing. In the context of the imaging problem, an apparent paradosical situation in which the image of a point source narrows down as the high-energy laser (HEL) beam propagates is discussed. 14 refs., 12 figs

Recovering of images degraded by atmosphere

Science.gov (United States)

Lin, Guang; Feng, Huajun; Xu, Zhihai; Li, Qi; Chen, Yueting

2017-08-01

Remote sensing images are seriously degraded by multiple scattering and bad weather. Through the analysis of the radiative transfer procedure in atmosphere, an image atmospheric degradation model considering the influence of atmospheric absorption multiple scattering and non-uniform distribution is proposed in this paper. Based on the proposed model, a novel recovering method is presented to eliminate atmospheric degradation. Mean-shift image segmentation and block-wise deconvolution are used to reduce time cost, retaining a good result. The recovering results indicate that the proposed method can significantly remove atmospheric degradation and effectively improve contrast compared with other removal methods. The results also illustrate that our method is suitable for various degraded remote sensing, including images with large field of view (FOV), images taken in side-glance situations, image degraded by atmospheric non-uniform distribution and images with various forms of clouds.

Transferability of Object-Oriented Image Analysis Methods for Slum Identification

Directory of Open Access Journals (Sweden)

Alfred Stein

2013-08-01

Full Text Available Updated spatial information on the dynamics of slums can be helpful to measure and evaluate progress of policies. Earlier studies have shown that semi-automatic detection of slums using remote sensing can be challenging considering the large variability in definition and appearance. In this study, we explored the potential of an object-oriented image analysis (OOA method to detect slums, using very high resolution (VHR imagery. This method integrated expert knowledge in the form of a local slum ontology. A set of image-based parameters was identified that was used for differentiating slums from non-slum areas in an OOA environment. The method was implemented on three subsets of the city of Ahmedabad, India. Results show that textural features such as entropy and contrast derived from a grey level co-occurrence matrix (GLCM and the size of image segments are stable parameters for classification of built-up areas and the identification of slums. Relation with classified slum objects, in terms of enclosed by slums and relative border with slums was used to refine classification. The analysis on three different subsets showed final accuracies ranging from 47% to 68%. We conclude that our method produces useful results as it allows including location specific adaptation, whereas generically applicable rulesets for slums are still to be developed.

Measurement of Lactate Content and Amide Proton Transfer Values in the Basal Ganglia of a Neonatal Piglet Hypoxic-Ischemic Brain Injury Model Using MRI.

Science.gov (United States)

Zheng, Y; Wang, X-M

2017-04-01

As amide proton transfer imaging is sensitive to protein content and intracellular pH, it has been widely used in the nervous system, including brain tumors and stroke. This work aimed to measure the lactate content and amide proton transfer values in the basal ganglia of a neonatal piglet hypoxic-ischemic brain injury model by using MR spectroscopy and amide proton transfer imaging. From 58 healthy neonatal piglets (3-5 days after birth; weight, 1-1.5 kg) selected initially, 9 piglets remained in the control group and 43 piglets, in the hypoxic-ischemic brain injury group. Single-section amide proton transfer imaging was performed at the coronal level of the basal ganglia. Amide proton transfer values of the bilateral basal ganglia were measured in all piglets. The ROI of MR spectroscopy imaging was the right basal ganglia, and the postprocessing was completed with LCModel software. After hypoxic-ischemic insult, the amide proton transfer values immediately decreased, and at 0-2 hours, they remained at their lowest level. Thereafter, they gradually increased and finally exceeded those of the control group at 48-72 hours. After hypoxic-ischemic insult, the lactate content increased immediately, was maximal at 2-6 hours, and then gradually decreased to the level of the control group. The amide proton transfer values were negatively correlated with lactate content ( r = -0.79, P < .05). This observation suggests that after hypoxic-ischemic insult, the recovery of pH was faster than that of lactate homeostasis. © 2017 by American Journal of Neuroradiology.

Extended Jiles-Atherton model for modelling the magnetic characteristics of isotropic materials

International Nuclear Information System (INIS)

Szewczyk, Roman; Bienkowski, Adam; Salach, Jacek