Sectors of solutions in three-dimensional gravity and black holes

International Nuclear Information System (INIS)

Fjelstad, Jens; Hwang, Stephen

2002-01-01

We examine the connection between three-dimensional gravity with negative cosmological constant and two-dimensional CFT via the Chern-Simons formulation. A set of generalized spectral flow transformations are shown to yield new sectors of solutions. One implication is that the microscopic calculation of the entropy of the Banados-Teitelboim-Zanelli (BTZ) black hole is corrected by a multiplicative factor with the result that it saturates the Bekenstein-Hawking expression

Sectors of solutions in three-dimensional gravity and black holes

Energy Technology Data Exchange (ETDEWEB)

Fjelstad, Jens E-mail: jens.fjelstad@kau.se; Hwang, Stephen E-mail: stephen.hwang@kau.se

2002-04-29

We examine the connection between three-dimensional gravity with negative cosmological constant and two-dimensional CFT via the Chern-Simons formulation. A set of generalized spectral flow transformations are shown to yield new sectors of solutions. One implication is that the microscopic calculation of the entropy of the Banados-Teitelboim-Zanelli (BTZ) black hole is corrected by a multiplicative factor with the result that it saturates the Bekenstein-Hawking expression.

Accelerated whole brain intracranial vessel wall imaging using black blood fast spin echo with compressed sensing (CS-SPACE).

Science.gov (United States)

Zhu, Chengcheng; Tian, Bing; Chen, Luguang; Eisenmenger, Laura; Raithel, Esther; Forman, Christoph; Ahn, Sinyeob; Laub, Gerhard; Liu, Qi; Lu, Jianping; Liu, Jing; Hess, Christopher; Saloner, David

2018-06-01

Develop and optimize an accelerated, high-resolution (0.5 mm isotropic) 3D black blood MRI technique to reduce scan time for whole-brain intracranial vessel wall imaging. A 3D accelerated T 1 -weighted fast-spin-echo prototype sequence using compressed sensing (CS-SPACE) was developed at 3T. Both the acquisition [echo train length (ETL), under-sampling factor] and reconstruction parameters (regularization parameter, number of iterations) were first optimized in 5 healthy volunteers. Ten patients with a variety of intracranial vascular disease presentations (aneurysm, atherosclerosis, dissection, vasculitis) were imaged with SPACE and optimized CS-SPACE, pre and post Gd contrast. Lumen/wall area, wall-to-lumen contrast ratio (CR), enhancement ratio (ER), sharpness, and qualitative scores (1-4) by two radiologists were recorded. The optimized CS-SPACE protocol has ETL 60, 20% k-space under-sampling, 0.002 regularization factor with 20 iterations. In patient studies, CS-SPACE and conventional SPACE had comparable image scores both pre- (3.35 ± 0.85 vs. 3.54 ± 0.65, p = 0.13) and post-contrast (3.72 ± 0.58 vs. 3.53 ± 0.57, p = 0.15), but the CS-SPACE acquisition was 37% faster (6:48 vs. 10:50). CS-SPACE agreed with SPACE for lumen/wall area, ER measurements and sharpness, but marginally reduced the CR. In the evaluation of intracranial vascular disease, CS-SPACE provides a substantial reduction in scan time compared to conventional T 1 -weighted SPACE while maintaining good image quality.

THREE-DIMENSIONAL SIMULATIONS OF VERTICAL MAGNETIC FLUX IN THE IMMEDIATE VICINITY OF BLACK HOLES

International Nuclear Information System (INIS)

Punsly, Brian; Igumenshchev, Igor V.; Hirose, Shigenobu

2009-01-01

This article reports on three-dimensional MHD simulations of non-rotating and rapidly rotating black holes and the adjacent black hole accretion disk magnetospheres. A particular emphasis is placed on the vertical magnetic flux that is advected inward from large radii and threads the equatorial plane near the event horizon. In both cases of non-rotating and rotating black holes, the existence of a significant vertical magnetic field in this region is like a switch that creates powerful jets. There are many similarities in the vertical flux dynamics in these two cases in spite of the tremendous enhancement of azimuthal twisting of the field lines and enhancement of the jet power because of an 'ergospheric disk' in the Kerr metric. A three-dimensional approach is essential because two-dimensional axisymmetric flows are incapable of revealing the nature of the vertical flux near a black hole. Poloidal field lines from the ergospheric accretion region have been visualized in three dimensions and much of the article is devoted to a formal classification of the different manifestations of the vertical flux in the Kerr case.

Integrated three-dimensional display of MR, CT, and PET images of the brain

International Nuclear Information System (INIS)

Levin, D.N.; Herrmann, A.; Chen, G.T.Y.

1988-01-01

MR, CT, and PET studies depict complementary aspects of brain anatomy and function. The authors' own image-processing software and a Pixar image computer were used to create three-dimensional models of brain soft tissues from MR images, of the skull and calcifications from CT scans, and of brain metabolism from PET images. An image correlation program, based on surface fitting, was used for retrospective registration and merging of these three-dimensional models. The results are demonstrated in a video clip showing how the operator may rotate and perform electronic surgery on the integrated, multimodality three-dimensional model of each patient's brain

Multimodality 3D Superposition and Automated Whole Brain Tractography: Comprehensive Printing of the Functional Brain.

Science.gov (United States)

Konakondla, Sanjay; Brimley, Cameron J; Sublett, Jesna Mathew; Stefanowicz, Edward; Flora, Sarah; Mongelluzzo, Gino; Schirmer, Clemens M

2017-09-29

Whole brain tractography using diffusion tensor imaging (DTI) sequences can be used to map cerebral connectivity; however, this can be time-consuming due to the manual component of image manipulation required, calling for the need for a standardized, automated, and accurate fiber tracking protocol with automatic whole brain tractography (AWBT). Interpreting conventional two-dimensional (2D) images, such as computed tomography (CT) and magnetic resonance imaging (MRI), as an intraoperative three-dimensional (3D) environment is a difficult task with recognized inter-operator variability. Three-dimensional printing in neurosurgery has gained significant traction in the past decade, and as software, equipment, and practices become more refined, trainee education, surgical skills, research endeavors, innovation, patient education, and outcomes via valued care is projected to improve. We describe a novel multimodality 3D superposition (MMTS) technique, which fuses multiple imaging sequences alongside cerebral tractography into one patient-specific 3D printed model. Inferences on cost and improved outcomes fueled by encouraging patient engagement are explored.

Three-dimensional massive gravity and the bigravity black hole

International Nuclear Information System (INIS)

Banados, Maximo; Theisen, Stefan

2009-01-01

We study three-dimensional massive gravity formulated as a theory with two dynamical metrics, like the f-g theories of Isham-Salam and Strathdee. The action is parity preserving and has no higher derivative terms. The spectrum contains a single massive graviton. This theory has several features discussed recently in TMG and NMG. We find warped black holes, a critical point, and generalized Brown-Henneaux boundary conditions.

Three-dimensional morphology of the human embryonic brain

Directory of Open Access Journals (Sweden)

N. Shiraishi

2015-09-01

Full Text Available The morphogenesis of the cerebral vesicles and ventricles was visualized in 3D movies using images derived from human embryo specimens between Carnegie stage 13 and 23 from the Kyoto Collection. These images were acquired with a magnetic resonance microscope equipped with a 2.35-T superconducting magnet. Three-dimensional images using the same scale demonstrated brain development and growth effectively. The non-uniform thickness of the brain tissue, which may indicate brain differentiation, was visualized with thickness-based surface color mapping. A closer view was obtained of the unique and complicated differentiation of the rhombencephalon, especially with regard to the internal view and thickening of the brain tissue. The present data contribute to a better understanding of brain and cerebral ventricle development.

Field in field technique in two-dimensional planning for whole brain irradiation; Tecnica field in field em planejamentos bidimensionais para irradiacao de cerebro total

Energy Technology Data Exchange (ETDEWEB)

Castro, A.L.S.; Campos, T.P.R., E-mail: radioterapia.andre@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil). Departamento de Engenharia Nuclear

2016-11-01

Radiotherapy is the most used clinical method used for brain metastases treatment, the most frequent secondary tumors provided by breast, lung and melanomas as primary origin. The protocols often use high daily doses and, depending on the irradiation technique there is high probability of complications in health tissues. In order to minimize adverse effects, it is important the dosimetric analysis of three-dimensional radiotherapy planning through tomographic images or, concerning to the 2D simulations, by the application of techniques that optimize dose distribution by increasing the homogeneity. The study aimed to compare the 2D and 3D conformal planning for total brain irradiation in a individual equivalent situation and evaluate the progress of these planning applying the field in field technique. The methodology consisted of simulating a two-dimensional planning, reproduce it on a set of tomographic images and compare it with the conformal plan for two fields and four fields (field in field). The results showed no significant difference between 2D and 3D planning for whole brain irradiation, and the field in field technique significantly improved the dose distribution in brain volume compared with two fields for the proposal situation. As conclusion, the two-dimensional plane for the four fields described was viable for whole brain irradiation in the treatment of brain metastases at the proposal situation. (author)

A pilot study of three dimensional color CT images of brain diseases to improve informed consent

International Nuclear Information System (INIS)

Tanizaki, Yoshio; Akiyama, Takenori; Hiraga, Kenji; Akaji, Kazunori

2005-01-01

We have described brain diseases to patients and their family using monochrome CT images. It is thought that patients have difficulties in giving their consent to our conventional explanation because their understanding of brain diseases is based on three dimensional and color images, however, standard CT images are two dimensional and gray scale images. We have been trying to use three dimensional color CT images to improve the typical patient's comprehension of brain diseases. We also try to simulate surgery using these images. Multi-slice CT accumulates precise isotropic voxel data within a half minute. These two dimensional and monochrome data are converted to three dimensional color CT images by 3D workstation. Three dimensional color CT images of each brain structures (e.g. scalp, skull, brain, ventricles and lesions) are created separately. Then, selected structures are fused together for different purposes. These images are able to rotate around any axis. Because the methods to generate three-dimensional color images have not established, we neurosurgeons must create these images. In particular, when an operation is required, the surgeon should create the images. In this paper, we demonstrate how three-dimensional color CT images can improve informed consent. (author)

Parallelization characteristics of a three-dimensional whole-core code DeCART

International Nuclear Information System (INIS)

Cho, J. Y.; Joo, H.K.; Kim, H. Y.; Lee, J. C.; Jang, M. H.

2003-01-01

Neutron transport calculation for three-dimensional amount of computing time but also huge memory. Therefore, whole-core codes such as DeCART need both also parallel computation and distributed memory capabilities. This paper is to implement such parallel capabilities based on MPI grouping and memory distribution on the DeCART code, and then to evaluate the performance by solving the C5G7 three-dimensional benchmark and a simplified three-dimensional SMART core problem. In C5G7 problem with 24 CPUs, a speedup of maximum 22 is obtained on IBM regatta machine and 21 on a LINUX cluster for the MOC kernel, which indicates good parallel performance of the DeCART code. The simplified SMART problem which need about 11 GBytes memory with one processors requires about 940 MBytes, which means that the DeCART code can now solve large core problems on affordable LINUX clusters

Three-Dimensional Computer Graphics Brain-Mapping Project

Science.gov (United States)

1988-03-24

1975-76, one of these brains was hand digitized. It was then reconstructed three dimensionally, using an Evans and Sutherland Picture System 2. This...Yakovlev Collection, we use the Evans and Sutherland Picture System 2 which we have been employing for this purpose for a dozen years. Its virtue is...careful, experimentally designed new protocol (See Figure 20). Most of these heads were imaged with Computed Tomography, thanks to Clint Stiles of Picker

Hamiltonian thermodynamics of charged three-dimensional dilatonic black holes

International Nuclear Information System (INIS)

Dias, Goncalo A. S.; Lemos, Jose P. S.

2008-01-01

The action for a class of three-dimensional dilaton-gravity theories, with an electromagnetic Maxwell field and a cosmological constant, can be recast in a Brans-Dicke-Maxwell type action, with its free ω parameter. For a negative cosmological constant, these theories have static, electrically charged, and spherically symmetric black hole solutions. Those theories with well formulated asymptotics are studied through a Hamiltonian formalism, and their thermodynamical properties are found out. The theories studied are general relativity (ω→±∞), a dimensionally reduced cylindrical four-dimensional general relativity theory (ω=0), and a theory representing a class of theories (ω=-3), all with a Maxwell term. The Hamiltonian formalism is set up in three dimensions through foliations on the right region of the Carter-Penrose diagram, with the bifurcation 1-sphere as the left boundary, and anti-de Sitter infinity as the right boundary. The metric functions on the foliated hypersurfaces and the radial component of the vector potential one-form are the canonical coordinates. The Hamiltonian action is written, the Hamiltonian being a sum of constraints. One finds a new action which yields an unconstrained theory with two pairs of canonical coordinates (M,P M ;Q,P Q ), where M is the mass parameter, which for ω M is the conjugate momenta of M, Q is the charge parameter, and P Q is its conjugate momentum. The resulting Hamiltonian is a sum of boundary terms only. A quantization of the theory is performed. The Schroedinger evolution operator is constructed, the trace is taken, and the partition function of the grand canonical ensemble is obtained, where the chemical potential is the scalar electric field φ. Like the uncharged cases studied previously, the charged black hole entropies differ, in general, from the usual quarter of the horizon area due to the dilaton.

Comparing three-dimensional serial optical coherence tomography histology to MRI imaging in the entire mouse brain

Science.gov (United States)

Castonguay, Alexandre; Lefebvre, Joël; Pouliot, Philippe; Lesage, Frédéric

2018-01-01

An automated serial histology setup combining optical coherence tomography (OCT) imaging with vibratome sectioning was used to image eight wild type mouse brains. The datasets resulted in thousands of volumetric tiles resolved at a voxel size of (4.9×4.9×6.5) μm3 stitched back together to give a three-dimensional map of the brain from which a template OCT brain was obtained. To assess deformation caused by tissue sectioning, reconstruction algorithms, and fixation, OCT datasets were compared to both in vivo and ex vivo magnetic resonance imaging (MRI) imaging. The OCT brain template yielded a highly detailed map of the brain structure, with a high contrast in white matter fiber bundles and was highly resemblant to the in vivo MRI template. Brain labeling using the Allen brain framework showed little variation in regional brain volume among imaging modalities with no statistical differences. The high correspondence between the OCT template brain and its in vivo counterpart demonstrates the potential of whole brain histology to validate in vivo imaging.

Three-Dimensional Blood-Brain Barrier Model for in vitro Studies of Neurovascular Pathology

Science.gov (United States)

Cho, Hansang; Seo, Ji Hae; Wong, Keith H. K.; Terasaki, Yasukazu; Park, Joseph; Bong, Kiwan; Arai, Ken; Lo, Eng H.; Irimia, Daniel

2015-10-01

Blood-brain barrier (BBB) pathology leads to neurovascular disorders and is an important target for therapies. However, the study of BBB pathology is difficult in the absence of models that are simple and relevant. In vivo animal models are highly relevant, however they are hampered by complex, multi-cellular interactions that are difficult to decouple. In vitro models of BBB are simpler, however they have limited functionality and relevance to disease processes. To address these limitations, we developed a 3-dimensional (3D) model of BBB on a microfluidic platform. We verified the tightness of the BBB by showing its ability to reduce the leakage of dyes and to block the transmigration of immune cells towards chemoattractants. Moreover, we verified the localization at endothelial cell boundaries of ZO-1 and VE-Cadherin, two components of tight and adherens junctions. To validate the functionality of the BBB model, we probed its disruption by neuro-inflammation mediators and ischemic conditions and measured the protective function of antioxidant and ROCK-inhibitor treatments. Overall, our 3D BBB model provides a robust platform, adequate for detailed functional studies of BBB and for the screening of BBB-targeting drugs in neurological diseases.

Thermodynamic properties of charged three-dimensional black holes in the scalar-tensor gravity theory

Science.gov (United States)

Dehghani, M.

2018-02-01

Making use of the suitable transformation relations, the action of three-dimensional Einstein-Maxwell-dilaton gravity theory has been obtained from that of scalar-tensor modified gravity theory coupled to the Maxwell's electrodynamics as the matter field. Two new classes of the static three-dimensional charged dilatonic black holes, as the exact solutions to the coupled scalar, electromagnetic and gravitational field equations, have been obtained in the Einstein frame. Also, it has been found that the scalar potential can be written in the form of a generalized Liouville-type potential. The conserved black hole charge and masses as well as the black entropy, temperature, and electric potential have been calculated from the geometrical and thermodynamical approaches, separately. Through comparison of the results arisen from these two alternative approaches, the validity of the thermodynamical first law has been proved for both of the new black hole solutions in the Einstein frame. Making use of the canonical ensemble method, a black hole stability or phase transition analysis has been performed. Regarding the black hole heat capacity, with the black hole charge as a constant, the points of type-1 and type-2 phase transitions have been determined. Also, the ranges of the black hole horizon radius at which the Einstein black holes are thermally stable have been obtained for both of the new black hole solutions. Then making use of the inverse transformation relations, two new classes of the string black hole solutions have been obtained from their Einstein counterpart. The thermodynamics and thermal stability of the new string black hole solutions have been investigated. It has been found that thermodynamic properties of the new charged black holes are identical in the Einstein and Jordan frames.

Vasovagal reactions in whole blood donors at three REDS-II blood centers in Brazil.

OpenAIRE

Gonçalez, TT; Sabino, EC; Schlumpf, KS; Wright, DJ; Leao, S; Sampaio, D; Takecian, PL; Proietti, AB; Murphy, E; Busch, M; Custer, B; NHLBI Retrovirus Epidemiology Donor Study-II REDS-II, International Component,

2012-01-01

In Brazil little is known about adverse reactions during donation and the donor characteristics that may be associated with such events. Donors are offered snacks and fluids before donating and are required to consume a light meal after donation. For these reasons the frequency of reactions may be different than those observed in other countries.A cross-sectional study was conducted of eligible whole blood donors at three large blood centers located in Brazil between July 2007 and December 20...

Blood-brain barrier-on-a-chip: Microphysiological systems that capture the complexity of the blood-central nervous system interface.

Science.gov (United States)

Phan, Duc Tt; Bender, R Hugh F; Andrejecsk, Jillian W; Sobrino, Agua; Hachey, Stephanie J; George, Steven C; Hughes, Christopher Cw

2017-11-01

The blood-brain barrier is a dynamic and highly organized structure that strictly regulates the molecules allowed to cross the brain vasculature into the central nervous system. The blood-brain barrier pathology has been associated with a number of central nervous system diseases, including vascular malformations, stroke/vascular dementia, Alzheimer's disease, multiple sclerosis, and various neurological tumors including glioblastoma multiforme. There is a compelling need for representative models of this critical interface. Current research relies heavily on animal models (mostly mice) or on two-dimensional (2D) in vitro models, neither of which fully capture the complexities of the human blood-brain barrier. Physiological differences between humans and mice make translation to the clinic problematic, while monolayer cultures cannot capture the inherently three-dimensional (3D) nature of the blood-brain barrier, which includes close association of the abluminal side of the endothelium with astrocyte foot-processes and pericytes. Here we discuss the central nervous system diseases associated with blood-brain barrier pathology, recent advances in the development of novel 3D blood-brain barrier -on-a-chip systems that better mimic the physiological complexity and structure of human blood-brain barrier, and provide an outlook on how these blood-brain barrier-on-a-chip systems can be used for central nervous system disease modeling. Impact statement The field of microphysiological systems is rapidly evolving as new technologies are introduced and our understanding of organ physiology develops. In this review, we focus on Blood-Brain Barrier (BBB) models, with a particular emphasis on how they relate to neurological disorders such as Alzheimer's disease, multiple sclerosis, stroke, cancer, and vascular malformations. We emphasize the importance of capturing the three-dimensional nature of the brain and the unique architecture of the BBB - something that until recently

Blood BDNF concentrations reflect brain-tissue BDNF levels across species

DEFF Research Database (Denmark)

Klein, Anders B; Williamson, Rebecca; Santini, Martin A

2011-01-01

Brain-derived neurotrophic factor (BDNF) is involved in synaptic plasticity, neuronal differentiation and survival of neurons. Observations of decreased serum BDNF levels in patients with neuropsychiatric disorders have highlighted the potential of BDNF as a biomarker, but so far there have been...... no studies directly comparing blood BDNF levels to brain BDNF levels in different species. We examined blood, serum, plasma and brain-tissue BDNF levels in three different mammalian species: rat, pig, and mouse, using an ELISA method. As a control, we included an analysis of blood and brain tissue from...... conditional BDNF knockout mice and their wild-type littermates. Whereas BDNF could readily be measured in rat blood, plasma and brain tissue, it was undetectable in mouse blood. In pigs, whole-blood levels of BDNF could not be measured with a commercially available ELISA kit, but pig plasma BDNF levels (mean...

Blood BDNF concentrations reflect brain-tissue BDNF levels across species

DEFF Research Database (Denmark)

Klein, Anders B; Williamson, Rebecca; Santini, Martin A

2011-01-01

no studies directly comparing blood BDNF levels to brain BDNF levels in different species. We examined blood, serum, plasma and brain-tissue BDNF levels in three different mammalian species: rat, pig, and mouse, using an ELISA method. As a control, we included an analysis of blood and brain tissue from......Brain-derived neurotrophic factor (BDNF) is involved in synaptic plasticity, neuronal differentiation and survival of neurons. Observations of decreased serum BDNF levels in patients with neuropsychiatric disorders have highlighted the potential of BDNF as a biomarker, but so far there have been...... conditional BDNF knockout mice and their wild-type littermates. Whereas BDNF could readily be measured in rat blood, plasma and brain tissue, it was undetectable in mouse blood. In pigs, whole-blood levels of BDNF could not be measured with a commercially available ELISA kit, but pig plasma BDNF levels (mean...

Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole

Energy Technology Data Exchange (ETDEWEB)

Sakalli, I.; Ovgun, A., E-mail: ali.ovgun@emu.edu.tr [Eastern Mediterranean University Famagusta, North Cyprus, Department of Physics (Turkey)

2015-09-15

We study the Hawking radiation of spin-1 particles (so-called vector particles) from a three-dimensional rotating black hole with scalar hair using a Hamilton–Jacobi ansatz. Using the Proca equation in the WKB approximation, we obtain the tunneling spectrum of vector particles. We recover the standard Hawking temperature corresponding to the emission of these particles from a rotating black hole with scalar hair.

A Novel Three-Dimensional Tool for Teaching Human Neuroanatomy

Science.gov (United States)

Estevez, Maureen E.; Lindgren, Kristen A.; Bergethon, Peter R.

2010-01-01

Three-dimensional (3D) visualization of neuroanatomy can be challenging for medical students. This knowledge is essential in order for students to correlate cross-sectional neuroanatomy and whole brain specimens within neuroscience curricula and to interpret clinical and radiological information as clinicians or researchers. This study implemented…

Three-dimensional power Doppler sonography: imaging and quantifying blood flow and vascularization.

Science.gov (United States)

Pairleitner, H; Steiner, H; Hasenoehrl, G; Staudach, A

1999-08-01

To assess the feasibility of imaging low-velocity blood flow in adnexal masses by transvaginal three-dimensional power Doppler sonography, to analyze three-dimensional power Doppler sonography data sets with a new computer-assisted method and to test the reproducibility of the technique. A commercially available 5-MHz Combison 530 ultrasound system was used to perform three-dimensional power Doppler sonography transvaginally. A cube (= volume of interest) was defined enclosing the vessels of the cyst and the Cartesian characteristics were stored on a hard disk. This cube was analyzed using specially designed software. Five indices representing vascularization (the vascularization index (VI) or blood flow (the flow index (FI)) or both (the vascularization-flow index (VFI)) were calculated. The intraobserver repeatability of cube definition and scan repetition was assessed using Hartley's test for homogeneous variances. Interobserver agreement was assessed by the Pearson correlation coefficient. Imaging of vessels with low-velocity blood flow by three-dimensional power Doppler sonography and cube definition was possible in all adnexal massed studied. In some cases even induced non-vascular flow related to endometriosis was detected. The calculated F value with intraobserver repeated Cartesian file-saving ranged from 0 to 18.8, with intraobserver scan repetition from 4.74 to 24.8 for VI, FI 1, FI 2 and VFI 1; for VFI 2 the calculated F value was 64. The interobserver correlation coefficient ranged between 0.83 and 0.92 for VI, FI 1, FI 2 and VFI 1; for VFI 2 the correlation coefficient was less than 0.75. Vessels with low-velocity blood flow can be imaged using three-dimensional power Doppler sonography. Induced non-vascular flow was detected in endometriotic cyst fluid. Three-dimensional power Doppler sonography combined with the cube method gave reproducible information for all indices except VFI 2. These indices might prove to be a new predictor in all fields of

Three-dimensional macroporous nanoelectronic networks as minimally invasive brain probes

Science.gov (United States)

Xie, Chong; Liu, Jia; Fu, Tian-Ming; Dai, Xiaochuan; Zhou, Wei; Lieber, Charles M.

2015-12-01

Direct electrical recording and stimulation of neural activity using micro-fabricated silicon and metal micro-wire probes have contributed extensively to basic neuroscience and therapeutic applications; however, the dimensional and mechanical mismatch of these probes with the brain tissue limits their stability in chronic implants and decreases the neuron-device contact. Here, we demonstrate the realization of a three-dimensional macroporous nanoelectronic brain probe that combines ultra-flexibility and subcellular feature sizes to overcome these limitations. Built-in strains controlling the local geometry of the macroporous devices are designed to optimize the neuron/probe interface and to promote integration with the brain tissue while introducing minimal mechanical perturbation. The ultra-flexible probes were implanted frozen into rodent brains and used to record multiplexed local field potentials and single-unit action potentials from the somatosensory cortex. Significantly, histology analysis revealed filling-in of neural tissue through the macroporous network and attractive neuron-probe interactions, consistent with long-term biocompatibility of the device.

Development of 2-D/1-D fusion method for three-dimensional whole-core heterogeneous neutron transport calculations

International Nuclear Information System (INIS)

Lee, Gil Soo

2006-02-01

To describe power distribution and multiplication factor of a reactor core accurately, it is necessary to perform calculations based on neutron transport equation considering heterogeneous geometry and scattering angles. These calculations require very heavy calculations and were nearly impossible with computers of old days. From the limitation of computing power, traditional approach of reactor core design consists of heterogeneous transport calculation in fuel assembly level and whole core diffusion nodal calculation with assembly homogenized properties, resulting from fuel assembly transport calculation. This approach may be effective in computation time, but it gives less accurate results for highly heterogeneous problems. As potential for whole core heterogeneous transport calculation became more feasible owing to rapid development of computing power during last several years, the interests in two and three dimensional whole core heterogeneous transport calculations by deterministic method are increased. For two dimensional calculation, there were several successful approaches using even parity transport equation with triangular meshes, S N method with refined rectangular meshes, the method of characteristics (MOC) with unstructured meshes, and so on. The work in this thesis originally started from the two dimensional whole core heterogeneous transport calculation by using MOC. After successful achievement in two dimensional calculation, there were efforts in three-dimensional whole-core heterogeneous transport calculation using MOC. Since direct extension to three dimensional calculation of MOC requires too much computing power, indirect approach to three dimensional calculation was considered.Thus, 2D/1D fusion method for three dimensional heterogeneous transport calculation was developed and successfully implemented in a computer code. The 2D/1D fusion method is synergistic combination of the MOC for radial 2-D calculation and S N -like methods for axial 1

Three-dimensional cloud characterization from paired whole-sky imaging cameras

International Nuclear Information System (INIS)

Allmen, M.; Kegelmeyer, W.P. Jr.

1994-01-01

Three-dimensional (3-D) cloud characterization permits the derivation of important cloud geometry properties such as fractional cloudiness, mean cloud and clear length, aspect ratio, and the morphology of cloud cover. These properties are needed as input to the hierarchical diagnosis (HD) and instantaneous radiative transfer (IRF) models, to validate sub-models for cloud occurrence and formation, and to Central Site radiative flux calculations. A full 3-D characterization will eventually require the integration of disparate Cloud and Radiation Testbed (CART) data sources: whole-sky imagers (WSIs), radar, satellites, ceilometers, volume-imaging lidar, and other sensors. In this paper, we demonstrate how an initial 3-D cloud property, cloud base height, can be determined from fusing paired times series of images from two whole-sky imagers

Three-dimensional neuroimaging

International Nuclear Information System (INIS)

Toga, A.W.

1990-01-01

This book reports on new neuroimaging technologies that are revolutionizing the study of the brain be enabling investigators to visualize its structure and entire pattern of functional activity in three dimensions. The book provides a theoretical and practical explanation of the new science of creating three-dimensional computer images of the brain. The coverage includes a review of the technology and methodology of neuroimaging, the instrumentation and procedures, issues of quantification, analytic protocols, and descriptions of neuroimaging systems. Examples are given to illustrate the use of three-dimensional enuroimaging to quantitate spatial measurements, perform analysis of autoradiographic and histological studies, and study the relationship between brain structure and function

Three-Dimensional Integration of Black Phosphorus Photodetector with Silicon Photonics and Nanoplasmonics.

Science.gov (United States)

Chen, Che; Youngblood, Nathan; Peng, Ruoming; Yoo, Daehan; Mohr, Daniel A; Johnson, Timothy W; Oh, Sang-Hyun; Li, Mo

2017-02-08

We demonstrate the integration of a black phosphorus photodetector in a hybrid, three-dimensional architecture of silicon photonics and metallic nanoplasmonics structures. This integration approach combines the advantages of the low propagation loss of silicon waveguides, high-field confinement of a plasmonic nanogap, and the narrow bandgap of black phosphorus to achieve high responsivity for detection of telecom-band, near-infrared light. Benefiting from an ultrashort channel (∼60 nm) and near-field enhancement enabled by the nanogap structure, the photodetector shows an intrinsic responsivity as high as 10 A/W afforded by internal gain mechanisms, and a 3 dB roll-off frequency of 150 MHz. This device demonstrates a promising approach for on-chip integration of three distinctive photonic systems, which, as a generic platform, may lead to future nanophotonic applications for biosensing, nonlinear optics, and optical signal processing.

Regular black hole in three dimensions

OpenAIRE

Myung, Yun Soo; Yoon, Myungseok

2008-01-01

We find a new black hole in three dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare thermodynamics of this black hole with that of non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy.

Three-dimensional morphologic description and visualization of brain anatomy from MR images

International Nuclear Information System (INIS)

Kraske, W.; George, F.W.; Zee, C.S.; Colletti, P.M.; Halls, J.M.; Boswell, W.O.

1989-01-01

The USC VOXAR-MRI system incorporates MR tissue classification algorithms to provide dynamic three- dimensional volumetric visualization and discrimination of brain anatomy and pathology for precision diagnosis, staging, and treatment planning. The VOXAR-MRI approach to tissue classification employs the three-dimensional reconstruction of various intracranial features from gray-scale morphologic erosion and dilation (GMED)-derived skeleton representation of the MR acquisition. Case presentations include an array of VOXAR-MRI-demonstrated tumors, abscesses, hematomas, and other lesions

Three-dimensional reconstruction of brain surface anatomy: technique comparison between flash and diffusion-weighted imaging

International Nuclear Information System (INIS)

Sun Jianzhong; Wang Zhikang; Gong Xiangyang

2006-01-01

Objective: To compare two methods 3D flash and diffusion-weighted images (DWI) in reconstructing the brain surface anatomy, and to evaluate their displaying ability, advantages, limitations and clinical application. Methods: Thrity normal cases were prospectively examined with 3D flash sequence and echo-planar DWI. Three-dimensional images were acquired with volume-rendering on workstation. Brain surface structures were evaluated and scored by a group of doctors. Results: Main structures of brain surface were clearly displayed on three-dimensional images based on 3D flash sequence. Average scores were all above 2.50. For images based on DWI, precentral gyrus, postcentral gyrus, superior parietal lobule, superior frontal gyrus, precentral sulcus, central sulcus, postcentral sulcus, intraparietal sulcus and superior frontal sulcus were best shown with average scores between 2.60-2.75, However, supramarginal gyrus, angular gyrus, middle frontal gyrus, inferior frontal gyrus, superior temporal gyrus, lateral sulcus, inferior frontal sulcus could not be well shown, with average scores between 1.67-2.48. Middle temporal gyrus, inferior temporal gyrus, superior temporal sulcus and inferior temporal sulcus can only get scores from 0.88 to 1.27. Scores of images based on 3D flash were much higher than that based on DWI with distinct differentiations, P values were all below 0.01. Conclusion: Three-dimensional images based on 3D flash can really display brain surface structures. It is very useful for anatomic researches. Three-dimensional reconstruction of brain surface based on DWI is a worthy technique to display brain surface anatomy, especially for frontal and parietal structures. (authors)

Late effects of whole brain irradiation within the therapeutic range

International Nuclear Information System (INIS)

Caveness, W.F.; Carsten, A.L.

1978-01-01

Whole brain exposure with supervoltage irradiation was carried out on three sets of Macaca mulatta. Two sets of 12 monkeys each, at puberty, received single and fractionated exposures respectively. One set of 21 monkeys in adulthood received a fractionated exposure. Exposure to 1000 rads in a single dose, at puberty, caused no late effects. Exposure to 1500 rads caused small areas of necrosis in the forebrain white matter at 26 weeks, but a much more extensive involvementat and beyond 52 weeks that included confluent areas of necrosis in gray and white matter. Brain loss resulted in ventricular dilatation. Gliomas appeared in two out of three monkeys at or beyond 52 weeks. Exposure to 2000 rads caused such a wide scatter of focal areas of necrosis, including those in the brain stem, that survival beyond 20-26 weeks was not possible. All showed enlarged ventricular systems. Whole brain exposure, 200 rads a day, five days a week, for a course of 4000 rads, at puberty, resulted in no delayed effects. An exposure to 6000 rads, in a six weeks course, caused small, less than 1 mm, widely scattered necrotic lesions with a predilection for the forebrain white matter but not excluding the central gray matter and brain stem, at 26 weeks. At 52 weeks, there was considerable mineralization of the lesions and widespread telangiectasia. In the developing lesions, multiple minute breaks in the blood brain barrier caused diffuse brain swelling, reflected by papilloedema. Whole brain exposure to 6000 rads in a six weeks course, in the adult, produced less effects than the same dose at puberty. The onset of the scattered necrotic lesions was later than expected, appearing in one out of three animals at 33 weeks, two out of three animals at 52 weeks, and two out of three at 104 weeks. The lesions at 104 weeks were predominantly mineralized, but were accompanied by a greater extent of telangiectasia than seen in the pubescent monkeys

Accelerated regression of brain metastases in patients receiving whole brain radiation and the topoisomerase II inhibitor, lucanthone

International Nuclear Information System (INIS)

Rowe, John D. del; Bello, Jacqueline; Mitnick, Robin; Sood, Brij; Filippi, Christopher; Moran, Justin Ph.D.; Freeman, Katherine; Mendez, Frances; Bases, Robert

1999-01-01

Purpose: To determine if lucanthone crossed the blood-brain barrier in experimental animals; and to determine accelerated tumor regression of human brain metastases treated jointly with lucanthone and whole brain radiation. Methods and Materials: The organ distribution of 3 H lucanthone in mice and 125 I lucanthone in rats was determined to learn if lucanthone crossed the blood-brain barrier. Size determinations were made of patients' brain metastases from magnetic resonance images or by computed tomography before and after treatment with 30 Gy whole brain radiation alone or with lucanthone. Results: The time course of lucanthone's distribution in brain was identical to that in muscle and heart after intraperitoneal or intravenous administration in experimental animals. Lucanthone, therefore, readily crossed the blood-brain barrier in experimental animals. Conclusion: Compared with radiation alone, the tumor regression in patients with brain metastases treated with lucanthone and radiation was accelerated, approaching significance using a permutation test at p = 0.0536

Prospects in deterministic three dimensional whole-core transport calculations

International Nuclear Information System (INIS)

Sanchez, Richard

2012-01-01

The point we made in this paper is that, although detailed and precise three-dimensional (3D) whole-core transport calculations may be obtained in the future with massively parallel computers, they would have an application to only some of the problems of the nuclear industry, more precisely those regarding multiphysics or for methodology validation or nuclear safety calculations. On the other hand, typical design reactor cycle calculations comprising many one-point core calculations can have very strict constraints in computing time and will not directly benefit from the advances in computations in large scale computers. Consequently, in this paper we review some of the deterministic 3D transport methods which in the very near future may have potential for industrial applications and, even with low-order approximations such as a low resolution in energy, might represent an advantage as compared with present industrial methodology, for which one of the main approximations is due to power reconstruction. These methods comprise the response-matrix method and methods based on the two-dimensional (2D) method of characteristics, such as the fusion method.

Dosimetric comparison of three-dimensional conformal and intensity modulated radiotherapy in brain glioma

International Nuclear Information System (INIS)

Lu Jie; Zhang Guifang; Bai Tong; Yin Yong; Fan Tingyong; Wu Chaoxia

2009-01-01

Objective: To investigate the dosimetry advantages of intensity modulated radiotherapy (IMRT)of brain glioma compared with that of three-dimensional conformal radiotherapy (SD CRT). Methods: Ten patients with brain glioma were enrolled in this study. Three-dimensional conf0rmal and intensity modulated radiotherapy plans were performed for each patient. The dose distributions of target volume and normal tissues, conformal index (CI) and heterogeneous index (HI) were analyzed using the dose-volume histogram (DVH). The prescription dose was 60 Gy in 30 fractions. Results: IMRT plans decrease the maximum dose and volume of brainstem, mean dose of affected side parotid and maximum dose of spinal-cord. The CI for PTV of IMRT was superior to that of SD CRT, the HI for PTV has no statistical significance of the two model plans. Conclusions: IMRT plans can obviously decrease the dose and volume of brainstem. IMRT is a potential method in the treatment of brain glioma, and dose escalation was possible in patients with brain glioma. (authors)

Global cerebral blood flow changes measured by brain perfusion SPECT immediately after whole brain irradiation

International Nuclear Information System (INIS)

Ohtawa, Nobuyuki; Machida, Kikuo; Honda, Norinari; Hosono, Makoto; Takahashi, Takeo

2003-01-01

Whole brain irradiation (WBI) is still a major treatment option for patients with metastatic brain tumor despite recent advances in chemotherapy and newer techniques of radiation therapy. Cerebral blood flow (CBF) of changes induced by whole brain radiation is not fully investigated, and the aim of the study was to measure CBF changes non-invasively with brain perfusion SPECT to correlate with treatment effect or prognosis. Total of 106 patients underwent WBI during April 1998 to March 2002. Both brain MRI and brain perfusion SPECT could be performed before (less than 1 week before or less than 10 Gy of WBI) and immediately after (between 1 week before and 2 weeks after the completion of WBI) the therapy in 17 of these patients. They, 10 men and 7 women, all had metastatic brain tumor with age range of 45 to 87 (mean of 61.4) years. Tc-99m brain perfusion agent (HMPAO in 4, ECD in 13) was rapidly administered in a 740-MBq dose to measure global and regional CBF according to Matsuda's method, which based on both Patlak plot and Lassens' linearity correction. Brain MRI was used to measure therapeutic response according to World Health Organization (WHO) classification as complete remission (CR), partial response (PR), no change (NC), and progressive disease (PD). Survival period was measured from the completion of WBI. Mean global CBF was 40.6 and 41.5 ml/100 g/min before and immediately after the WBI, respectively. Four patients increased (greater than 10%) their global mean CBF, 10 unchanged (less than 10% increase or decrease), and 3 decreased after the WBI. The WBI achieved CR in none, PR in 8, NC in 6, and PD in 3 on brain MRI. Change in global mean CBF (mean±SD) was significantly larger in PR (4.3±2.0 ml/100 g/min, p=0.002) and in NC (-0.1±4.5) than in PD (-3.9±6.4, P=0.002, P=0.016, respectively). Survival was not significantly (p>0.05) different among the patients with CR (20 weeks), NC (48 weeks), and PD (21 weeks). Change in global CBF and survival was

Three-charge black holes on a circle

International Nuclear Information System (INIS)

Harmark, Troels; Obers, Niels A.; Roenne, Peter B.; Kristjansson, Kristjan R.

2007-01-01

We study phases of five-dimensional three-charge black holes with a circle in their transverse space. In particular, when the black hole is localized on the circle we compute the corrections to the metric and corresponding thermodynamics in the limit of small mass. When taking the near-extremal limit, this gives the corrections to the finite entropy of the extremal three-charge black hole as a function of the energy above extremality. For the partial extremal limit with two charges sent to infinity and one finite we show that the first correction to the entropy is in agreement with the microscopic entropy by taking into account that the number of branes shift as a consequence of the interactions across the transverse circle. Beyond these analytical results, we also numerically obtain the entire phase of non- and near-extremal three- and two-charge black holes localized on a circle. More generally, we find in this paper a rich phase structure, including a new phase of three-charge black holes that are non-uniformly distributed on the circle. All these three-charge black hole phases are found via a map that relates them to the phases of five-dimensional neutral Kaluza-Klein black holes

Three-dimensional textural analysis of brain images reveals distributed grey-matter abnormalities in schizophrenia

International Nuclear Information System (INIS)

Ganeshan, Balaji; Miles, Kenneth A.; Critchley, Hugo D.; Young, Rupert C.D.; Chatwin, Christopher R.; Gurling, Hugh M.D.

2010-01-01

Three-dimensional (3-D) selective- and relative-scale texture analysis (TA) was applied to structural magnetic resonance (MR) brain images to quantify the presence of grey-matter (GM) and white-matter (WM) textural abnormalities associated with schizophrenia. Brain TA comprised volume filtration using the Laplacian of Gaussian filter to highlight fine, medium and coarse textures within GM and WM, followed by texture quantification. Relative TA (e.g. ratio of fine to medium) was also computed. T1-weighted MR whole-brain images from 32 participants with diagnosis of schizophrenia (n = 10) and healthy controls (n = 22) were examined. Five patients possessed marker alleles (SZ8) associated with schizophrenia on chromosome 8 in the pericentriolar material 1 gene while the remaining five had not inherited any of the alleles (SZ0). Filtered fine GM texture (mean grey-level intensity; MGI) most significantly differentiated schizophrenic patients from controls (P = 0.0058; area under the receiver-operating characteristic curve = 0.809, sensitivity = 90%, specificity = 70%). WM measurements did not distinguish the two groups. Filtered GM and WM textures (MGI) correlated with total GM and WM volume respectively. Medium-to-coarse GM entropy distinguished SZ0 from controls (P = 0.0069) while measures from SZ8 were intermediate between the two. 3-D TA of brain MR enables detection of subtle distributed morphological features associated with schizophrenia, determined partly by susceptibility genes. (orig.)

Three-dimensional textural analysis of brain images reveals distributed grey-matter abnormalities in schizophrenia

Energy Technology Data Exchange (ETDEWEB)

Ganeshan, Balaji [University of Sussex, Falmer, Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Brighton (United Kingdom); University of Sussex, Falmer, Department of Engineering and Design, Brighton (United Kingdom); Miles, Kenneth A.; Critchley, Hugo D. [University of Sussex, Falmer, Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Brighton (United Kingdom); Young, Rupert C.D.; Chatwin, Christopher R. [University of Sussex, Falmer, Department of Engineering and Design, Brighton (United Kingdom); Gurling, Hugh M.D. [University College London, Department of Mental Health Sciences, London (United Kingdom)

2010-04-15

Three-dimensional (3-D) selective- and relative-scale texture analysis (TA) was applied to structural magnetic resonance (MR) brain images to quantify the presence of grey-matter (GM) and white-matter (WM) textural abnormalities associated with schizophrenia. Brain TA comprised volume filtration using the Laplacian of Gaussian filter to highlight fine, medium and coarse textures within GM and WM, followed by texture quantification. Relative TA (e.g. ratio of fine to medium) was also computed. T1-weighted MR whole-brain images from 32 participants with diagnosis of schizophrenia (n = 10) and healthy controls (n = 22) were examined. Five patients possessed marker alleles (SZ8) associated with schizophrenia on chromosome 8 in the pericentriolar material 1 gene while the remaining five had not inherited any of the alleles (SZ0). Filtered fine GM texture (mean grey-level intensity; MGI) most significantly differentiated schizophrenic patients from controls (P = 0.0058; area under the receiver-operating characteristic curve = 0.809, sensitivity = 90%, specificity = 70%). WM measurements did not distinguish the two groups. Filtered GM and WM textures (MGI) correlated with total GM and WM volume respectively. Medium-to-coarse GM entropy distinguished SZ0 from controls (P = 0.0069) while measures from SZ8 were intermediate between the two. 3-D TA of brain MR enables detection of subtle distributed morphological features associated with schizophrenia, determined partly by susceptibility genes. (orig.)

Parallelization of a three-dimensional whole core transport code DeCART

Energy Technology Data Exchange (ETDEWEB)

Jin Young, Cho; Han Gyu, Joo; Ha Yong, Kim; Moon-Hee, Chang [Korea Atomic Energy Research Institute, Yuseong-gu, Daejon (Korea, Republic of)

2003-07-01

Parallelization of the DeCART (deterministic core analysis based on ray tracing) code is presented that reduces the computational burden of the tremendous computing time and memory required in three-dimensional whole core transport calculations. The parallelization employs the concept of MPI grouping and the MPI/OpenMP mixed scheme as well. Since most of the computing time and memory are used in MOC (method of characteristics) and the multi-group CMFD (coarse mesh finite difference) calculation in DeCART, variables and subroutines related to these two modules are the primary targets for parallelization. Specifically, the ray tracing module was parallelized using a planar domain decomposition scheme and an angular domain decomposition scheme. The parallel performance of the DeCART code is evaluated by solving a rodded variation of the C5G7MOX three dimensional benchmark problem and a simplified three-dimensional SMART PWR core problem. In C5G7MOX problem with 24 CPUs, a speedup of maximum 21 is obtained on an IBM Regatta machine and 22 on a LINUX Cluster in the MOC kernel, which indicates good parallel performance of the DeCART code. In the simplified SMART problem, the memory requirement of about 11 GBytes in the single processor cases reduces to 940 Mbytes with 24 processors, which means that the DeCART code can now solve large core problems with affordable LINUX clusters. (authors)

Three-dimensional reconstruction of indoor whole elements based on mobile LiDAR point cloud data

Science.gov (United States)

Gong, Yuejian; Mao, Wenbo; Bi, Jiantao; Ji, Wei; He, Zhanjun

2014-11-01

Ground-based LiDAR is one of the most effective city modeling tools at present, which has been widely used for three-dimensional reconstruction of outdoor objects. However, as for indoor objects, there are some technical bottlenecks due to lack of GPS signal. In this paper, based on the high-precision indoor point cloud data which was obtained by LiDAR, an international advanced indoor mobile measuring equipment, high -precision model was fulfilled for all indoor ancillary facilities. The point cloud data we employed also contain color feature, which is extracted by fusion with CCD images. Thus, it has both space geometric feature and spectral information which can be used for constructing objects' surface and restoring color and texture of the geometric model. Based on Autodesk CAD platform and with help of PointSence plug, three-dimensional reconstruction of indoor whole elements was realized. Specifically, Pointools Edit Pro was adopted to edit the point cloud, then different types of indoor point cloud data was processed, including data format conversion, outline extracting and texture mapping of the point cloud model. Finally, three-dimensional visualization of the real-world indoor was completed. Experiment results showed that high-precision 3D point cloud data obtained by indoor mobile measuring equipment can be used for indoor whole elements' 3-d reconstruction and that methods proposed in this paper can efficiently realize the 3 -d construction of indoor whole elements. Moreover, the modeling precision could be controlled within 5 cm, which was proved to be a satisfactory result.

Computerized emission transaxial tomography and determination of local brain function

International Nuclear Information System (INIS)

Kuhl, D.E.; Alavi, A.; Reivich, M.; Edwards, R.Q.; Fenton, C.A.; Zimmerman, R.A.

1975-01-01

Accurate knowledge of regional function in the brain would be of great value for the detection and localization of a wide variety of diseases and for assessment of patients under treatment. The management of patients would be greatly improved with a day-to-day knowledge of the status of blood flow, blood volume, metabolism, permeability, brain swelling, and other functions on a local basis throughout the brain. In the past this kind of information has not been available. Instead, function has usually been examined only for the organ as a whole and regional information has been restricted to morphology as determined by radiographic or radionuclide imaging studies. Three-dimensional radionuclide reconstruction imaging will become more important in the study of the brain, providing accurate measurement of radionuclide concentration within functional structural units of the brain. Measurement of local function with three-dimensional resolution throughout the brain and without the necessity for intracarotid injection of indicator could therefore provide a significant advance over presently available methods

Log corrections to entropy of three dimensional black holes with soft hair

Science.gov (United States)

Grumiller, Daniel; Perez, Alfredo; Tempo, David; Troncoso, Ricardo

2017-08-01

We calculate log corrections to the entropy of three-dimensional black holes with "soft hairy" boundary conditions. Their thermodynamics possesses some special features that preclude a naive direct evaluation of these corrections, so we follow two different approaches. The first one exploits that the BTZ black hole belongs to the spectrum of Brown-Henneaux as well as soft hairy boundary conditions, so that the respective log corrections are related through a suitable change of the thermodynamic ensemble. In the second approach the analogue of modular invariance is considered for dual theories with anisotropic scaling of Lifshitz type with dynamical exponent z at the boundary. On the gravity side such scalings arise for KdV-type boundary conditions, which provide a specific 1-parameter family of multi-trace deformations of the usual AdS3/CFT2 setup, with Brown-Henneaux corresponding to z = 1 and soft hairy boundary conditions to the limiting case z → 0+. Both approaches agree in the case of BTZ black holes for any non-negative z. Finally, for soft hairy boundary conditions we show that not only the leading term, but also the log corrections to the entropy of black flowers endowed with affine û (1) soft hair charges exclusively depend on the zero modes and hence coincide with the ones for BTZ black holes.

Brain volume measurement using three-dimensional magnetic resonance images

International Nuclear Information System (INIS)

Ishimaru, Yoshihiro

1996-01-01

This study was designed to validate accurate measurement method of human brain volume using three dimensional (3D) MRI data on a workstation, and to establish optimal correcting method of human brain volume on diagnosis of brain atrophy. 3D MRI data were acquired by fast SPGR sequence using 1.5 T MR imager. 3D MRI data were segmented by region growing method and 3D image was displayed by surface rendering method on the workstation. Brain volume was measured by the volume measurement function of the workstation. In order to validate the accurate measurement method, phantoms and a specimen of human brain were examined. Phantom volume was measured by changing the lower level of threshold value. At the appropriate threshold value, percentage of error of phantoms and the specimen were within 0.6% and 0.08%, respectively. To establish the optimal correcting method, 130 normal volunteers were examined. Brain volumes corrected with height weight, body surface area, and alternative skull volume were evaluated. Brain volume index, which is defined as dividing brain volume by alternative skull volume, had the best correlation with age (r=0.624, p<0.05). No gender differences was observed in brain volume index in contrast to in brain volume. The clinical usefulness of this correcting method for brain atrophy diagnosis was evaluated in 85 patients. Diagnosis by 2D spin echo MR images was compared with brain volume index. Diagnosis of brain atrophy by 2D MR image was concordant with the evaluation by brain volume index. These results indicated that this measurement method had high accuracy, and it was important to set the appropriate threshold value. Brain volume index was the appropriate indication for evaluation of human brain volume, and was considered to be useful for the diagnosis of brain atrophy. (author)

Five-dimensional black hole capture cross sections

International Nuclear Information System (INIS)

Gooding, Cisco; Frolov, Andrei V.

2008-01-01

We study scattering and capture of particles by a rotating black hole in the five-dimensional spacetime described by the Myers-Perry metric. The equations of geodesic motion are integrable, and allow us to calculate capture conditions for a free particle sent towards a black hole from infinity. We introduce a three-dimensional impact parameter describing asymptotic initial conditions in the scattering problem for a given initial velocity. The capture surface in impact parameter space is a sphere for a nonrotating black hole, and is deformed for a rotating black hole. We obtain asymptotic expressions that describe such deformations for small rotational parameters, and use numerical calculations to investigate the arbitrary rotation case, which allows us to visualize the capture surface as extremal rotation is approached

Generalized uncertainty principle and entropy of three-dimensional rotating acoustic black hole

International Nuclear Information System (INIS)

Zhao, HuiHua; Li, GuangLiang; Zhang, LiChun

2012-01-01

Using the new equation of state density from the generalized uncertainty principle, we investigate statistics entropy of a 3-dimensional rotating acoustic black hole. When λ introduced in the generalized uncertainty principle takes a specific value, we obtain an area entropy and a correction term associated with the acoustic black hole. In this method, there does not exist any divergence and one needs not the small mass approximation in the original brick-wall model. -- Highlights: ► Statistics entropy of a 3-dimensional rotating acoustic black hole is studied. ► We obtain an area entropy and a correction term associated with it. ► We make λ introduced in the generalized uncertainty principle take a specific value. ► There does not exist any divergence in this method.

Hawking radiation and propagation of massive charged scalar field on a three-dimensional Gödel black hole

Science.gov (United States)

González, P. A.; Övgün, Ali; Saavedra, Joel; Vásquez, Yerko

2018-06-01

In this paper we consider the three-dimensional Gödel black hole as a background and we study the vector particle tunneling from this background in order to obtain the Hawking temperature. Then, we study the propagation of a massive charged scalar field and we find the quasinormal modes analytically, which turns out be unstable as a consequence of the existence of closed time-like curves. Also, we consider the flux at the horizon and at infinity, and we compute the reflection and transmission coefficients as well as the absorption cross section. Mainly, we show that massive charged scalar waves can be superradiantly amplified by the three-dimensional Gödel black hole and that the coefficients have an oscillatory behavior. Moreover, the absorption cross section is null at the high frequency limit and for certain values of the frequency.

Three-dimensional optoacoustic tomography using a conventional ultrasound linear detector array: whole-body tomographic system for small animals.

Science.gov (United States)

Gateau, Jerome; Caballero, Miguel Angel Araque; Dima, Alexander; Ntziachristos, Vasilis

2013-01-01

Optoacoustic imaging relies on the detection of ultrasonic waves induced by laser pulse excitations to map optical absorption in biological tissue. A tomographic geometry employing a conventional ultrasound linear detector array for volumetric optoacoustic imaging is reported. The geometry is based on a translate-rotate scanning motion of the detector array, and capitalizes on the geometrical characteristics of the transducer assembly to provide a large solid angular detection aperture. A system for three-dimensional whole-body optoacoustic tomography of small animals is implemented. The detection geometry was tested using a 128-element linear array (5.0∕7.0 MHz, Acuson L7, Siemens), moved by steps with a rotation∕translation stage assembly. Translation and rotation range of 13.5 mm and 180°, respectively, were implemented. Optoacoustic emissions were induced in tissue-mimicking phantoms and ex vivo mice using a pulsed laser operating in the near-IR spectral range at 760 nm. Volumetric images were formed using a filtered backprojection algorithm. The resolution of the optoacoustic tomography system was measured to be better than 130 μm in-plane and 330 μm in elevation (full width half maximum), and to be homogenous along a 15 mm diameter cross section due to the translate-rotate scanning geometry. Whole-body volumetric optoacoustic images of mice were performed ex vivo, and imaged organs and blood vessels through the intact abdominal and head regions were correlated to the mouse anatomy. Overall, the feasibility of three-dimensional and high-resolution whole-body optoacoustic imaging of small animal using a conventional linear array was demonstrated. Furthermore, the scanning geometry may be used for other linear arrays and is therefore expected to be of great interest for optoacoustic tomography at macroscopic and mesoscopic scale. Specifically, conventional detector arrays with higher central frequencies may be investigated.

Re-irradiation for metastatic brain tumors with whole-brain radiotherapy

International Nuclear Information System (INIS)

Akiba, Takeshi; Kunieda, Etsuo; Kogawa, Asuka; Komatsu, Tetsuya; Tamai, Yoshifumi; Ohizumi, Yukio

2012-01-01

The objective of this study was to determine whether second whole-brain irradiation is beneficial for patients previously treated with whole-brain irradiation. A retrospective analysis was done for 31 patients with brain metastases who had undergone re-irradiation. Initial whole-brain irradiation was performed with 30 Gy/10 fractions for 87% of these patients. Whole-brain re-irradiation was performed with 30 Gy/10 fractions for 42% of these patients (3-40 Gy/1-20 fractions). Three patients underwent a third whole-brain irradiation. The median interval between the initial irradiation and re-irradiation was 10 months (range: 2-69 months). The median survival time after re-irradiation was 4 months (range: 1-21 months). The symptomatic improvement rate after re-irradiation was 68%, and the partial and complete tumor response rate was 55%. Fifty-two percent of the patients developed Grade 1 acute reactions. On magnetic resonance imaging, brain atrophy was observed in 36% of these patients after the initial irradiation and 74% after re-irradiation. Grade ≥2 encephalopathy or cognitive disturbance was observed in 10 patients (32%) after re-irradiation. Based on univariate analysis, significant factors related to survival after re-irradiation were the location of the primary cancer (P=0.003) and the Karnofsky performance status at the time of re-irradiation (P=0.008). A Karnofsky performance status ≥70 was significant based on multivariate analysis (P=0.050). Whole-brain re-irradiation for brain metastases placed only a slight burden on patients and was effective for symptomatic improvement. However, their remaining survival time was limited and the incidence of cognitive disturbance was rather high. (author)

Three-dimensional neural cultures produce networks that mimic native brain activity.

Science.gov (United States)

Bourke, Justin L; Quigley, Anita F; Duchi, Serena; O'Connell, Cathal D; Crook, Jeremy M; Wallace, Gordon G; Cook, Mark J; Kapsa, Robert M I

2018-02-01

Development of brain function is critically dependent on neuronal networks organized through three dimensions. Culture of central nervous system neurons has traditionally been limited to two dimensions, restricting growth patterns and network formation to a single plane. Here, with the use of multichannel extracellular microelectrode arrays, we demonstrate that neurons cultured in a true three-dimensional environment recapitulate native neuronal network formation and produce functional outcomes more akin to in vivo neuronal network activity. Copyright © 2017 John Wiley & Sons, Ltd.

Magnetic resonance imaging-three-dimensional printing technology fabricates customized scaffolds for brain tissue engineering

Institute of Scientific and Technical Information of China (English)

Feng Fu; Chong Chen; Sai Zhang; Ming-liang Zhao; Xiao-hong Li; Zhe Qin; Chao Xu; Xu-yi Chen; Rui-xin Li; Li-na Wang; Ding-wei Peng; Hong-tao Sun; Yue Tu

2017-01-01

Conventional fabrication methods lack the ability to control both macro- and micro-structures of generated scaffolds. Three-dimensional printing is a solid free-form fabrication method that provides novel ways to create customized scaffolds with high precision and accuracy. In this study, an electrically controlled cortical impactor was used to induce randomized brain tissue defects. The overall shape of scaffolds was designed using rat-specific anatomical data obtained from magnetic resonance imaging, and the internal structure was created by computer- aided design. As the result of limitations arising from insufficient resolution of the manufacturing process, we magnified the size of the cavity model prototype five-fold to successfully fabricate customized collagen-chitosan scaffolds using three-dimensional printing. Results demonstrated that scaffolds have three-dimensional porous structures, high porosity, highly specific surface areas, pore connectivity and good internal characteristics. Neural stem cells co-cultured with scaffolds showed good viability, indicating good biocompatibility and biodegradability. This technique may be a promising new strategy for regenerating complex damaged brain tissues, and helps pave the way toward personalized medicine.

Diagnosis of Alzheimer's disease using brain SPECT with three-dimensional stereotactic surface projections

International Nuclear Information System (INIS)

Hanyu, Haruo; Asano, Tetsuichi; Kogure, Daiji; Abe, Shine; Iwamoto, Toshihiko; Takasaki, Masaru

2001-01-01

We compared the diagnostic usefulness of three-dimensional stereotactic surface projection (3D-SSP) with that of standard transaxial images in brain SPECT in patients with Alzheimer's disease (AD). The subjects consisted of 69 patients with AD and 60 patients with non-AD, including vascular dementia, Parkinson's disease with dementia, frontotemporal dementia, other dementing diseases and neuropsychiatric diseases. Standard transaxial section and 3D-SSP SPECT images with N-isopropyl-p-[ 123 I] iodoamphetamine were blindly interpreted by three examiners and were classified into the following three patterns: typical AD, atypical AD, and not indicative AD patterns. The 3D-SSP images demonstrated reductions of cerebral blood flow in the parieto-temporal association cortex and posterior cingulate gyrus more clearly and easily than the standard transaxial images. The diagnostic sensitivity and specificity were 93% and 85% with 3D-SSP and 83% and 82% with standard transaxial section respectively. 3D-SSP was especially useful for early or atypical AD which showed no characteristic perfusion abnormalities on standard transaxial images. These results suggest that SPECT with 3D-SSP provides an sensitive as well as accurate tool for the diagnosis of AD. (author)

Thermodynamics of Einstein-Born-Infeld black holes in three dimensions

International Nuclear Information System (INIS)

Myung, Yun Soo; Kim, Yong-Wan; Park, Young-Jai

2008-01-01

We show that all thermodynamic quantities of the Einstein-Born-Infeld black holes in three dimensions can be obtained from the dilaton and its potential of two-dimensional dilaton gravity through dimensional reduction. These are all between nonrotating uncharged BTZ (Banados-Teitelboim-Zanelli) black hole (NBTZ) and charged BTZ black hole (CBTZ).

Three dimensional cerebral blood flow in patients with idiopathic Parkinson's disease

International Nuclear Information System (INIS)

Hata, Takashi

1987-01-01

Three dimensional local cerebral blood flow values were measured in 28 patients with idiopathic Parkinson's disease without dementia and 17 control subjects, by means of xenon enhanced CT method using low concentration cold xenon and autoradiographic strategy. The results demonstrated that local cerebral perfusion in the patients with Parkinson's disease decreased with close correlations with aging and severity of the clinical symptoms and signs. Stepwise multiregression analysis revealed that mean CBF values and 1-CBF values through thalamus and white matter decreased primarily depending on aging and degree of brain atrophy, whereas 1-CBF values through basal ganglia decreased depending on severity of disease. The spatial distributions of 1-CBF were maintained normally and symmetrically even in the severely affected cases or in those with hemiparkinsonism, therefore hyperfrontalities were well preserved in all of the patients. Acute intravenous administration of L-DOPA gave rise to a diffuse increase in 1-CBF only in the patients and the increment was more prominent in patients severely affected than in those mildly affected. It was concluded that reduction of 1-CBF in the basal ganglia and cortex may be attributed to hypometabolism in the mesostriatal and mesocortical dopaminergic system. (author)

Three dimensional cerebral blood flow in patients with idiopathic Parkinson's disease

Energy Technology Data Exchange (ETDEWEB)

Hata, Takashi

1987-07-01

Three dimensional local cerebral blood flow values were measured in 28 patients with idiopathic Parkinson's disease without dementia and 17 control subjects, by means of xenon enhanced CT method using low concentration cold xenon and autoradiographic strategy. The results demonstrated that local cerebral perfusion in the patients with Parkinson's disease decreased with close correlations with aging and severity of the clinical symptoms and signs. Stepwise multiregression analysis revealed that mean CBF values and 1-CBF values through thalamus and white matter decreased primarily depending on aging and degree of brain atrophy, whereas 1-CBF values through basal ganglia decreased depending on severity of disease. The spatial distributions of 1-CBF were maintained normally and symmetrically even in the severely affected cases or in those with hemiparkinsonism, therefore hyperfrontalities were well preserved in all of the patients. Acute intravenous administration of L-DOPA gave rise to a diffuse increase in 1-CBF only in the patients and the increment was more prominent in patients severely affected than in those mildly affected. It was concluded that reduction of 1-CBF in the basal ganglia and cortex may be attributed to hypometabolism in the mesostriatal and mesocortical dopaminergic system.

Three-dimensional sonographic measurement of normal fetal brain volume during the second half of pregnancy

NARCIS (Netherlands)

N.M. Roelfsema; W.C.J. Hop (Wim); S.M. Boito; J.W. Wladimiroff (Juriy)

2004-01-01

textabstractObjectives: This study was undertaken to develop a three-dimensional (3D) ultrasound method of measuring fetal brain volume. Study design: Serial 3D sonographic measurements of fetal brain volume were made in 68 normal singleton pregnancies at 18 to 34 weeks of gestation. A comparison

Quadcopter control in three-dimensional space using a noninvasive motor imagery based brain-computer interface

Science.gov (United States)

LaFleur, Karl; Cassady, Kaitlin; Doud, Alexander; Shades, Kaleb; Rogin, Eitan; He, Bin

2013-01-01

Objective At the balanced intersection of human and machine adaptation is found the optimally functioning brain-computer interface (BCI). In this study, we report a novel experiment of BCI controlling a robotic quadcopter in three-dimensional physical space using noninvasive scalp EEG in human subjects. We then quantify the performance of this system using metrics suitable for asynchronous BCI. Lastly, we examine the impact that operation of a real world device has on subjects’ control with comparison to a two-dimensional virtual cursor task. Approach Five human subjects were trained to modulate their sensorimotor rhythms to control an AR Drone navigating a three-dimensional physical space. Visual feedback was provided via a forward facing camera on the hull of the drone. Individual subjects were able to accurately acquire up to 90.5% of all valid targets presented while travelling at an average straight-line speed of 0.69 m/s. Significance Freely exploring and interacting with the world around us is a crucial element of autonomy that is lost in the context of neurodegenerative disease. Brain-computer interfaces are systems that aim to restore or enhance a user’s ability to interact with the environment via a computer and through the use of only thought. We demonstrate for the first time the ability to control a flying robot in the three-dimensional physical space using noninvasive scalp recorded EEG in humans. Our work indicates the potential of noninvasive EEG based BCI systems to accomplish complex control in three-dimensional physical space. The present study may serve as a framework for the investigation of multidimensional non-invasive brain-computer interface control in a physical environment using telepresence robotics. PMID:23735712

Magnetized black holes and black rings in the higher dimensional dilaton gravity

International Nuclear Information System (INIS)

Yazadjiev, Stoytcho S.

2006-01-01

In this paper we consider magnetized black holes and black rings in the higher dimensional dilaton gravity. Our study is based on exact solutions generated by applying a Harrison transformation to known asymptotically flat black hole and black ring solutions in higher dimensional spacetimes. The explicit solutions include the magnetized version of the higher dimensional Schwarzschild-Tangherlini black holes, Myers-Perry black holes, and five-dimensional (dipole) black rings. The basic physical quantities of the magnetized objects are calculated. We also discuss some properties of the solutions and their thermodynamics. The ultrarelativistic limits of the magnetized solutions are briefly discussed and an explicit example is given for the D-dimensional magnetized Schwarzschild-Tangherlini black holes

Polynitroxylated Pegylated Hemoglobin-A Novel, Small Volume Therapeutic for Traumatic Brain Injury Resuscitation: Comparison to Whole Blood and Dose Response Evaluation.

Science.gov (United States)

Brockman, Erik C; Jackson, Travis C; Dixon, C Edward; Bayɪr, Hülya; Clark, Robert S B; Vagni, Vincent; Feldman, Keri; Byrd, Catherine; Ma, Li; Hsia, Carleton; Kochanek, Patrick M

2017-04-01

Resuscitation with polynitroxylated pegylated hemoglobin (PNPH), a pegylated bovine hemoglobin decorated with nitroxides, eliminated the need for fluid administration, reduced intracranial pressure (ICP) and brain edema, and produced neuroprotection in vitro and in vivo versus Lactated Ringer's solution (LR) in experimental traumatic brain injury (TBI) plus hemorrhagic shock (HS). We hypothesized that resuscitation with PNPH would improve acute physiology versus whole blood after TBI+HS and would be safe and effective across a wide dosage range. Anesthetized mice underwent controlled cortical impact and severe HS to mean arterial pressure (MAP) of 25-27 mm Hg for 35 min, then were resuscitated with PNPH, autologous whole blood, or LR. Markers of acute physiology, including mean arterial blood pressure (MAP), heart rate (HR), blood gases/chemistries, and brain oxygenation (PbtO 2 ), were monitored for 90 min on room air followed by 15 min on 100% oxygen. In a second experiment, the protocol was repeated, except mice were resuscitated with PNPH with doses between 2 and 100 mL/kg. ICP and 24 h %-brain water were evaluated. PNPH-resuscitated mice had higher MAP and lower HR post-resuscitation versus blood or LR (p < 0.01). PNPH-resuscitated mice, versus those resuscitated with blood or LR, also had higher pH and lower serum potassium (p < 0.05). Blood-resuscitated mice, however, had higher PbtO 2 versus those resuscitated with LR and PNPH, although PNPH had higher PbtO 2 versus LR (p < 0.05). PNPH was well tolerated across the dosing range and dramatically reduced fluid requirements in all doses-even 2 or 5 mL/kg (p < 0.001). ICP was significantly lower in PNPH-treated mice for most doses tested versus in LR-treated mice, although %-brain water did not differ between groups. Resuscitation with PNPH, versus resuscitation with LR or blood, improved MAP, HR, and ICP, reduced acidosis and hyperkalemia, and was well tolerated and effective

Polynitroxylated Pegylated Hemoglobin—A Novel, Small Volume Therapeutic for Traumatic Brain Injury Resuscitation: Comparison to Whole Blood and Dose Response Evaluation

Science.gov (United States)

Brockman, Erik C.; Jackson, Travis C.; Dixon, C. Edward; Bayɪr, Hülya; Clark, Robert S. B.; Vagni, Vincent; Feldman, Keri; Byrd, Catherine; Ma, Li; Hsia, Carleton

2017-01-01

Abstract Resuscitation with polynitroxylated pegylated hemoglobin (PNPH), a pegylated bovine hemoglobin decorated with nitroxides, eliminated the need for fluid administration, reduced intracranial pressure (ICP) and brain edema, and produced neuroprotection in vitro and in vivo versus Lactated Ringer's solution (LR) in experimental traumatic brain injury (TBI) plus hemorrhagic shock (HS). We hypothesized that resuscitation with PNPH would improve acute physiology versus whole blood after TBI+HS and would be safe and effective across a wide dosage range. Anesthetized mice underwent controlled cortical impact and severe HS to mean arterial pressure (MAP) of 25–27 mm Hg for 35 min, then were resuscitated with PNPH, autologous whole blood, or LR. Markers of acute physiology, including mean arterial blood pressure (MAP), heart rate (HR), blood gases/chemistries, and brain oxygenation (PbtO2), were monitored for 90 min on room air followed by 15 min on 100% oxygen. In a second experiment, the protocol was repeated, except mice were resuscitated with PNPH with doses between 2 and 100 mL/kg. ICP and 24 h %-brain water were evaluated. PNPH-resuscitated mice had higher MAP and lower HR post-resuscitation versus blood or LR (p < 0.01). PNPH-resuscitated mice, versus those resuscitated with blood or LR, also had higher pH and lower serum potassium (p < 0.05). Blood-resuscitated mice, however, had higher PbtO2 versus those resuscitated with LR and PNPH, although PNPH had higher PbtO2 versus LR (p < 0.05). PNPH was well tolerated across the dosing range and dramatically reduced fluid requirements in all doses—even 2 or 5 mL/kg (p < 0.001). ICP was significantly lower in PNPH-treated mice for most doses tested versus in LR-treated mice, although %-brain water did not differ between groups. Resuscitation with PNPH, versus resuscitation with LR or blood, improved MAP, HR, and ICP, reduced acidosis and hyperkalemia, and was well tolerated and

Diffusion tensor imaging and three-dimensional brain fiber tracking for the diagnosis of multiple sclerosis

Energy Technology Data Exchange (ETDEWEB)

Bing, Hu; Hong, Shan; Mingyue, Luo; Shaoqiong, Chen; Wang, Kang; Bingjun, He; Yan, Zou [Department of Radiology, the 3rd Affiliated Hospital of Sun Yat-sen Univ., Guangzhou (China); Binbin, Ye

2007-02-15

Objective: To demonstrate the diffusion tensor imaging (DTI) characteristics of multiple sclerosis (MS) plaques, periplaque white matter regions and normal appearing white matter (NAWM) regions in patients with MS, and to evaluate the clinical values of DTI and three-dimensional brain fiber tracking for the diagnosis of MS. Methods: Conventional MRI and DTI were performed in 32 patients with MS and 32 age-matched control subjects. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) maps were generated and coregistered with T{sub 2}-weighted MR images. FA and ADC values were calculated in regions of interest in plaques, periplaque white matter regions, NAWM regions and white matter regions in control subjects. And three-dimensional brain fiber tracking maps were generated by using the DTI. Results: The ADC was (1.233 {+-} 0.119) x 10{sup -3} mm{sup 2}/s in MS plaques, (0.973 {+-} 0.098) x 10{sup -3} mm{sup 2}/s in periplaque white matter regions, (0.748 {+-} 0.089) x 10{sup -3} mm{sup 2}/s in NAWM, and (0.620 {+-} 0.094) x 10{sup -3} mm{sup 2}/s in control subjects. The FA was 0.225 {+-} 0.052 in MS plaques, 0.311 {+-} 0.050 in periplaque white matter regions, 0.421 {+-} 0.070 in NAWM, and 0.476 {+-} 0.069 in control subjects. Significant differences in FA and ADC values were observed among all white matter regions (P<0.01). MS plaques were demonstrated in three-dimensional brain fiber tracking maps. Conclusion: FA and ADC maps are helpful for the evaluation of all white matter changes of MS. The abnormalities of white matter fiber tracts in MS plaques could be demonstrated in three-dimensional brain fiber tracking maps. (authors)

Diffusion tensor imaging and three-dimensional brain fiber tracking for the diagnosis of multiple sclerosis

International Nuclear Information System (INIS)

Hu Bing; Shan Hong; Luo Mingyue; Chen Shaoqiong; Kang Wang; He Bingjun; Zou Yan; Ye Binbin

2007-01-01

Objective: To demonstrate the diffusion tensor imaging (DTI) characteristics of multiple sclerosis (MS) plaques, periplaque white matter regions and normal appearing white matter (NAWM) regions in patients with MS, and to evaluate the clinical values of DTI and three-dimensional brain fiber tracking for the diagnosis of MS. Methods: Conventional MRI and DTI were performed in 32 patients with MS and 32 age-matched control subjects. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) maps were generated and coregistered with T 2 -weighted MR images. FA and ADC values were calculated in regions of interest in plaques, periplaque white matter regions, NAWM regions and white matter regions in control subjects. And three-dimensional brain fiber tracking maps were generated by using the DTI. Results: The ADC was (1.233 ± 0.119) x 10 -3 mm 2 /s in MS plaques, (0.973 ± 0.098) x 10 -3 mm 2 /s in periplaque white matter regions, (0.748 ± 0.089) x 10 -3 mm 2 /s in NAWM, and (0.620 ± 0.094) x 10 -3 mm 2 /s in control subjects. The FA was 0.225 ± 0.052 in MS plaques, 0.311 ± 0.050 in periplaque white matter regions, 0.421 ± 0.070 in NAWM, and 0.476 ± 0.069 in control subjects. Significant differences in FA and ADC values were observed among all white matter regions (P<0.01). MS plaques were demonstrated in three-dimensional brain fiber tracking maps. Conclusion: FA and ADC maps are helpful for the evaluation of all white matter changes of MS. The abnormalities of white matter fiber tracts in MS plaques could be demonstrated in three-dimensional brain fiber tracking maps. (authors)

TDat: An Efficient Platform for Processing Petabyte-Scale Whole-Brain Volumetric Images.

Science.gov (United States)

Li, Yuxin; Gong, Hui; Yang, Xiaoquan; Yuan, Jing; Jiang, Tao; Li, Xiangning; Sun, Qingtao; Zhu, Dan; Wang, Zhenyu; Luo, Qingming; Li, Anan

2017-01-01

Three-dimensional imaging of whole mammalian brains at single-neuron resolution has generated terabyte (TB)- and even petabyte (PB)-sized datasets. Due to their size, processing these massive image datasets can be hindered by the computer hardware and software typically found in biological laboratories. To fill this gap, we have developed an efficient platform named TDat, which adopts a novel data reformatting strategy by reading cuboid data and employing parallel computing. In data reformatting, TDat is more efficient than any other software. In data accessing, we adopted parallelization to fully explore the capability for data transmission in computers. We applied TDat in large-volume data rigid registration and neuron tracing in whole-brain data with single-neuron resolution, which has never been demonstrated in other studies. We also showed its compatibility with various computing platforms, image processing software and imaging systems.

Fermionic field perturbations of a three-dimensional Lifshitz black hole in conformal gravity

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, P.A. [Facultad de Ingenieria y Ciencias, Universidad Diego Portales, Santiago (Chile); Vasquez, Yerko; Villalobos, Ruth Noemi [Universidad de La Serena, Departamento de Fisica y Astronomia, Facultad de Ciencias, La Serena (Chile)

2017-09-15

We study the propagation of massless fermionic fields in the background of a three-dimensional Lifshitz black hole, which is a solution of conformal gravity. The black-hole solution is characterized by a vanishing dynamical exponent. Then we compute analytically the quasinormal modes, the area spectrum, and the absorption cross section for fermionic fields. The analysis of the quasinormal modes shows that the fermionic perturbations are stable in this background. The area and entropy spectrum are evenly spaced. In the low frequency limit, it is observed that there is a range of values of the angular momentum of the mode that contributes to the absorption cross section, whereas it vanishes in the high frequency limit. In addition, by a suitable change of variables a gravitational soliton can also be obtained and the stability of the quasinormal modes are studied and ensured. (orig.)

Fermion tunneling from higher-dimensional black holes

International Nuclear Information System (INIS)

Lin Kai; Yang Shuzheng

2009-01-01

Via the semiclassical approximation method, we study the 1/2-spin fermion tunneling from a higher-dimensional black hole. In our work, the Dirac equations are transformed into a simple form, and then we simplify the fermion tunneling research to the study of the Hamilton-Jacobi equation in curved space-time. Finally, we get the fermion tunneling rates and the Hawking temperatures at the event horizon of higher-dimensional black holes. We study fermion tunneling of a higher-dimensional Schwarzschild black hole and a higher-dimensional spherically symmetric quintessence black hole. In fact, this method is also applicable to the study of fermion tunneling from four-dimensional or lower-dimensional black holes, and we will take the rainbow-Finsler black hole as an example in order to make the fact explicit.

Three-dimensional visualization of myocardial motion and blood flow with cine-MR images

International Nuclear Information System (INIS)

Oshiro, Osamu; Matani, Ayumu; Chihara, Kunihiro; Mikami, Taisei; Kitabatake, Akira.

1997-01-01

This paper describes a three-dimensional (3D) reconstruction and presentation method to visualize myocardial motion and blood flow in a heart using cine-MR (magnetic resonance) images. Firstly, the region of myocardium and blood were segmented with certain threshold gray values. Secondly, some slices were interpolated linearly to reconstruct a 3D static image. Finally, a 3D dynamic image was presented with displaying the 3D static images sequentially. The experimental results indicate that this method enables to visualize not only normal but also abnormal blood flow in cine-mode. (author)

Three-dimensional intracellular structure of a whole rice mesophyll cell observed with FIB-SEM.

Science.gov (United States)

Oi, Takao; Enomoto, Sakiko; Nakao, Tomoyo; Arai, Shigeo; Yamane, Koji; Taniguchi, Mitsutaka

2017-07-01

Ultrathin sections of rice leaf blades observed two-dimensionally using a transmission electron microscope (TEM) show that the chlorenchyma is composed of lobed mesophyll cells, with intricate cell boundaries, and lined with chloroplasts. The lobed cell shape and chloroplast positioning are believed to enhance the area available for the gas exchange surface for photosynthesis in rice leaves. However, a cell image revealing the three-dimensional (3-D) ultrastructure of rice mesophyll cells has not been visualized. In this study, a whole rice mesophyll cell was observed using a focused ion beam scanning electron microscope (FIB-SEM), which provides many serial sections automatically, rapidly and correctly, thereby enabling 3-D cell structure reconstruction. Rice leaf blades were fixed chemically using the method for conventional TEM observation, embedded in resin and subsequently set in the FIB-SEM chamber. Specimen blocks were sectioned transversely using the FIB, and block-face images were captured using the SEM. The sectioning and imaging were repeated overnight for 200-500 slices (each 50 nm thick). The resultant large-volume image stacks ( x = 25 μm, y = 25 μm, z = 10-25 μm) contained one or two whole mesophyll cells. The 3-D models of whole mesophyll cells were reconstructed using image processing software. The reconstructed cell models were discoid shaped with several lobes around the cell periphery. The cell shape increased the surface area, and the ratio of surface area to volume was twice that of a cylinder having the same volume. The chloroplasts occupied half the cell volume and spread as sheets along the cell lobes, covering most of the inner cell surface, with adjacent chloroplasts in close contact with each other. Cellular and sub-cellular ultrastructures of a whole mesophyll cell in a rice leaf blade are demonstrated three-dimensionally using a FIB-SEM. The 3-D models and numerical information support the hypothesis that rice mesophyll

Noncommutative geometry-inspired rotating black hole in three ...

Indian Academy of Sciences (India)

We find a new rotating black hole in three-dimensional anti-de Sitter space using an anisotropic perfect fluid inspired by the noncommutative black hole. We deduce the thermodynamical quantities of this black hole and compare them with those of a rotating BTZ solution and give corrections to the area law to get the exact ...

Nanotoxicity of poly(n-butylcyano-acrylate) nanoparticles at the blood-brain barrier, in human whole blood and in vivo.

Science.gov (United States)

Kolter, Marise; Ott, Melanie; Hauer, Christian; Reimold, Isolde; Fricker, Gert

2015-01-10

Therapy of diseases of the central nervous system is a major challenge since drugs have to overcome the blood-brain barrier (BBB). A powerful strategy to enhance cerebral drug concentration is administration of drug-loaded poly(n-butylcyano-acrylate) (PBCA) nanoparticles coated with polysorbate 80 (PS80). This study evaluates the toxicity of PBCA-nanoparticles at the BBB, representing the target organ, the inflammatory response in human whole blood, as the site of administration and in a rat model in vivo. PBCA-nanoparticles were prepared by a mini-emulsion method and characterized concerning size, surface charge, shape and PS80-adsorption. The influence on metabolic activity, cell viability and integrity of the BBB was analyzed in an in vitro model of the BBB. In ex vivo experiments in human whole blood the release of 12 inflammatory cytokines was investigated. In addition, the inflammatory response was studied in vivo in rats and complemented with the analysis of different organ toxicity parameters. PBCA-nanoparticles showed time- and concentration-dependent effects on metabolic activity, cell viability and BBB integrity. No cell death or loss of metabolic activity was observed for nanoparticle-concentrations ≤500μg/ml up to 3h of treatment. Within 12 tested inflammatory cytokines, only interleukin-8 displayed a significant release after nanoparticle exposure in human blood. No severe inflammatory processes or organ damages were identified in rats in vivo. Thus, PBCA-nanoparticles are a promising drug delivery system to overcome the BBB since they showed hardly any cytotoxic or inflammatory effect at therapeutic concentrations and incubation times. Copyright © 2014 Elsevier B.V. All rights reserved.

arXiv Hawking radiation and propagation of massive charged scalar field on a three-dimensional G\\"odel black hole

CERN Document Server

González, P.A.; Saavedra, Joel; Vásquez, Yerko

2018-05-18

In this paper we consider the three-dimensional G\\"{o}del black hole as a background and we study the vector particle tunneling from this background in order to obtain the Hawking temperature. Then, we study the propagation of a massive charged scalar field and we find the quasinormal modes analytically, which turns out be unstable as a consequence of the existence of closed time-like curves. Also, we consider the flux at the horizon and at infinity, and we compute the reflection and transmission coefficients as well as the absorption cross section. Mainly, we show that massive charged scalar waves can be superradiantly amplified by the three-dimensional G\\"{o}del black hole and that the coefficients have an oscillatory behavior. Moreover, the absorption cross section is null at the high frequency limit and for certain values of the frequency.

The Three-Dimensional Architecture of the Internal Capsule of the Human Brain Demonstrated by Fiber Dissection Technique

Directory of Open Access Journals (Sweden)

Cristina Goga

2015-01-01

Full Text Available The fiber dissection technique involves peeling away white matter fiber tracts of the brain to display its three-dimensional anatomic arrangement. The intricate three-dimensional configuration and structure of the internal capsule (IC is not well defined. By using the fiber dissection technique, our aim was to expose and study the IC to achieve a clearer conception of its configuration and relationships with neighboring white matter fibers and central nuclei. The lateral and medial aspects of the temporal lobes of twenty, previously frozen, formalin-fixed human brains were dissected under the operating microscope using the fiber dissection technique.

The Blood-Brain Barrier: Connecting the Gut and the Brain

OpenAIRE

Banks, William A.

2008-01-01

The BBB prevents the unrestricted exchange of substances between the central nervous system (CNS) and the blood. The blood-brain barrier (BBB) also conveys information between the CNS and the gastrointestinal (GI) tract through several mechanisms. Here, we review three of those mechanisms. First, the BBB selectively transports some peptides and regulatory proteins in the blood-to-brain or the brain-to-blood direction. The ability of GI hormones to affect functions of the BBB, as illustrated b...

Comparison of one-, two-, and three-dimensional measurements of childhood brain tumors.

Science.gov (United States)

Warren, K E; Patronas, N; Aikin, A A; Albert, P S; Balis, F M

2001-09-19

End points for assessing drug activity in brain tumors are determined by measuring the change in tumor size by magnetic resonance imaging (MRI) relative to a pretreatment or best-response scan. Traditionally, two-dimensional (2D) tumor measurements have been used, but one-dimensional (1D) measurements have recently been proposed as an alternative. Because software to estimate three-dimensional (3D) tumor volume from digitized MRI images is available, we compared all three methods of tumor measurement for childhood brain tumors and clinical outcome. Tumor size from 130 MRI scans from 32 patients (32 baseline and 98 follow-up scans, for a total of 130 scans; median, three scans per patient; range, two to 18 scans) was measured by each method. Tumor-response category (partial response, minor response, stable disease, or progressive disease) was determined from the percentage change in tumor size between the baseline or best-response scan and follow-up scans. Time to clinical progression was independently determined by chart review. All statistical tests were two-sided. Concordances between 1D and 2D, 1D and 3D, and 2D and 3D were 83% (95% confidence interval [CI] = 67% to 99%), 61% (95% CI = 47% to 75%), and 66% (95% CI = 52% to 80%), respectively, on follow-up scans. Concordances for 1D and 3D and for 2D and 3D were statistically significantly lower than the concordance for 1D and 2D (Ptumors in the minor response and progressive-disease categories. Median times to progression measured by the 1D, 2D, and 3D methods were 154, 105, and 112 days, respectively, compared with 114 days based on neurologic symptoms and signs (P = .09 for overall comparison). Detection of partial responses was not influenced by the measurement method, but estimating time to disease progression may be method dependent for childhood brain tumors.

Three-dimensional imaging of the optic nerve using magnetic resonance angiography. Application to anterior communicating artery aneurysm and craniopharingioma

International Nuclear Information System (INIS)

Okuyama, Tohru; Fukuyama, Atsushi; Fukuyama, Koichi; Ikeno, Kunihiro; Araki, Hiroyuki; Okada, Kinya; Sohma, Noriko

2005-01-01

The purpose of this investigation was to analyze three-dimensional images of the optic nerve obtained by magnetic resonance angiography (MRA) in cases of anterior communicating artery aneurysm and craniopharingioma. Four ruptured anterior communicating artery aneurysms, five non-ruptured anterior communicating artery aneurysms and two craniopharingiomas were examined. The images were taken using MR/i Hispeed Plus 1.5 T Infinity version, and analyzed by Advantage Work station AW4.1. The routine MR imaging parameters are shown in Table. The imaging time was about 10 minutes. Analysis was made by reformation of images parallel to the optic nerve obtained from the original MRA images. The optic nerve and brain tumor were traced with paintbrush from one sheet to another of the reformed images after subtraction of the blood vessels around the anterior communicating artery in these reformed images, and then three-dimensional images were constructed. Three-dimensional images of the blood vessels were reconstructed from MIP (maximum intensity projection) images using the threshold method. The optic nerve and anterior communicating arterial aneurysm or brain tumor were both observed in the overlapped 3D-SSD (shaded surface display) images. The analysis time was about 15 minutes. Three-dimensional images of the optic nerve and anterior communicating artery aneurysm or brain tumor were able to be made in all cases. As a preoperative investigation for anterior communicating artery aneurysm or suprasellar brain tumor, we considered that three-dimensional imaging of the optic nerve is useful in the operative approach because the optic nerve acts as a merkmal for the anterior communicating aneurysm or brain tumor. (author)

Curvature invariant characterization of event horizons of four-dimensional black holes conformal to stationary black holes

Science.gov (United States)

McNutt, David D.

2017-11-01

We introduce three approaches to generate curvature invariants that transform covariantly under a conformal transformation of a four-dimensional spacetime. For any black hole conformally related to a stationary black hole, we show how a set of conformally covariant invariants can be combined to produce a conformally covariant invariant that detects the event horizon of the conformally related black hole. As an application we consider the rotating dynamical black holes conformally related to the Kerr-Newman-Unti-Tamburino-(anti)-de Sitter spacetimes and construct an invariant that detects the conformal Killing horizon along with a second invariant that detects the conformal stationary limit surface. In addition, we present necessary conditions for a dynamical black hole to be conformally related to a stationary black hole and apply these conditions to the ingoing Kerr-Vaidya and Vaidya black hole solutions to determine if they are conformally related to stationary black holes for particular choices of the mass function. While two of the three approaches cannot be generalized to higher dimensions, we discuss the existence of a conformally covariant invariant that will detect the event horizon for any higher dimensional black hole conformally related to a stationary black hole which admits at least two conformally covariant invariants, including all vacuum spacetimes.

Three-dimensional inversion recovery manganese-enhanced MRI of mouse brain using super-resolution reconstruction to visualize nuclei involved in higher brain function.

Science.gov (United States)

Poole, Dana S; Plenge, Esben; Poot, Dirk H J; Lakke, Egbert A J F; Niessen, Wiro J; Meijering, Erik; van der Weerd, Louise

2014-07-01

The visualization of activity in mouse brain using inversion recovery spin echo (IR-SE) manganese-enhanced MRI (MEMRI) provides unique contrast, but suffers from poor resolution in the slice-encoding direction. Super-resolution reconstruction (SRR) is a resolution-enhancing post-processing technique in which multiple low-resolution slice stacks are combined into a single volume of high isotropic resolution using computational methods. In this study, we investigated, first, whether SRR can improve the three-dimensional resolution of IR-SE MEMRI in the slice selection direction, whilst maintaining or improving the contrast-to-noise ratio of the two-dimensional slice stacks. Second, the contrast-to-noise ratio of SRR IR-SE MEMRI was compared with a conventional three-dimensional gradient echo (GE) acquisition. Quantitative experiments were performed on a phantom containing compartments of various manganese concentrations. The results showed that, with comparable scan times, the signal-to-noise ratio of three-dimensional GE acquisition is higher than that of SRR IR-SE MEMRI. However, the contrast-to-noise ratio between different compartments can be superior with SRR IR-SE MEMRI, depending on the chosen inversion time. In vivo experiments were performed in mice receiving manganese using an implanted osmotic pump. The results showed that SRR works well as a resolution-enhancing technique in IR-SE MEMRI experiments. In addition, the SRR image also shows a number of brain structures that are more clearly discernible from the surrounding tissues than in three-dimensional GE acquisition, including a number of nuclei with specific higher brain functions, such as memory, stress, anxiety and reward behavior. Copyright © 2014 John Wiley & Sons, Ltd.

Whole-brain radiation therapy for brain metastases: detrimental or beneficial?

International Nuclear Information System (INIS)

Gemici, Cengiz; Yaprak, Gokhan

2015-01-01

Stereotactic radiosurgery is frequently used, either alone or together with whole-brain radiation therapy to treat brain metastases from solid tumors. Certain experts and radiation oncology groups have proposed replacing whole-brain radiation therapy with stereotactic radiosurgery alone for the management of brain metastases. Although randomized trials have favored adding whole-brain radiation therapy to stereotactic radiosurgery for most end points, a recent meta-analysis demonstrated a survival disadvantage for patients treated with whole-brain radiation therapy and stereotactic radiosurgery compared with patients treated with stereotactic radiosurgery alone. However the apparent detrimental effect of adding whole-brain radiation therapy to stereotactic radiosurgery reported in this meta-analysis may be the result of inhomogeneous distribution of the patients with respect to tumor histologies, molecular histologic subtypes, and extracranial tumor stages between the groups rather than a real effect. Unfortunately, soon after this meta-analysis was published, even as an abstract, use of whole-brain radiation therapy in managing brain metastases has become controversial among radiation oncologists. The American Society of Radiation Oncology recently recommended, in their “Choose Wisely” campaign, against routinely adding whole-brain radiation therapy to stereotactic radiosurgery to treat brain metastases. However, this situation creates conflict for radiation oncologists who believe that there are enough high level of evidence for the effectiveness of whole-brain radiation therapy in the treatment of brain metastases

Three-dimensional printing and pediatric liver disease.

Science.gov (United States)

Alkhouri, Naim; Zein, Nizar N

2016-10-01

Enthusiastic physicians and medical researchers are investigating the role of three-dimensional printing in medicine. The purpose of the current review is to provide a concise summary of the role of three-dimensional printing technology as it relates to the field of pediatric hepatology and liver transplantation. Our group and others have recently demonstrated the feasibility of printing three-dimensional livers with identical anatomical and geometrical landmarks to the native liver to facilitate presurgical planning of complex liver surgeries. Medical educators are exploring the use of three-dimensional printed organs in anatomy classes and surgical residencies. Moreover, mini-livers are being developed by regenerative medicine scientist as a way to test new drugs and, eventually, whole livers will be grown in the laboratory to replace organs with end-stage disease solving the organ shortage problem. From presurgical planning to medical education to ultimately the bioprinting of whole organs for transplantation, three-dimensional printing will change medicine as we know in the next few years.

Distributed organization of a brain microcircuit analysed by three-dimensional modeling: the olfactory bulb

Directory of Open Access Journals (Sweden)

Michele eMigliore

2014-04-01

Full Text Available The functional consequences of the laminar organization observed in cortical systems cannot be easily studied using standard experimental techniques, abstract theoretical representations, or dimensionally reduced models built from scratch. To solve this problem we have developed a full implementation of an olfactory bulb microcircuit using realistic three-dimensional inputs, cell morphologies, and network connectivity. The results provide new insights into the relations between the functional properties of individual cells and the networks in which they are embedded. To our knowledge, this is the first model of the mitral-granule cell network to include a realistic representation of the experimentally-recorded complex spatial patterns elicited in the glomerular layer by natural odor stimulation. Although the olfactory bulb, due to its organization, has unique advantages with respect to other brain systems, the method is completely general, and can be integrated with more general approaches to other systems. The model makes experimentally testable predictions on distributed processing and on the differential backpropagation of somatic action potentials in each lateral dendrite following odor learning, providing a powerful three-dimensional framework for investigating the functions of brain microcircuits.

Heat engine in the three-dimensional spacetime

Energy Technology Data Exchange (ETDEWEB)

Mo, Jie-Xiong [Institute of Theoretical Physics, Lingnan Normal University,Zhanjiang, 524048, Guangdong (China); Department of Physics, Lingnan Normal University,Zhanjiang, 524048, Guangdong (China); Liang, Feng [Department of Physics, Lingnan Normal University,Zhanjiang, 524048, Guangdong (China); Li, Gu-Qiang [Institute of Theoretical Physics, Lingnan Normal University,Zhanjiang, 524048, Guangdong (China); Department of Physics, Lingnan Normal University,Zhanjiang, 524048, Guangdong (China)

2017-03-02

We define a kind of heat engine via three-dimensional charged BTZ black holes. This case is quite subtle and needs to be more careful. The heat flow along the isochores does not equal to zero since the specific heat C{sub V}≠0 and this point completely differs from the cases discussed before whose isochores and adiabats are identical. So one cannot simply apply the paradigm in the former literatures. However, if one introduces a new thermodynamic parameter associated with the renormalization length scale, the above problem can be solved. We obtain the analytical efficiency expression of the three-dimensional charged BTZ black hole heat engine for two different schemes. Moreover, we double check with the exact formula. Our result presents the first specific example for the sound correctness of the exact efficiency formula. We argue that the three-dimensional charged BTZ black hole can be viewed as a toy model for further investigation of holographic heat engine. Furthermore, we compare our result with that of the Carnot cycle and extend the former result to three-dimensional spacetime. In this sense, the result in this paper would be complementary to those obtained in four-dimensional spacetime or ever higher. Last but not the least, the heat engine efficiency discussed in this paper may serve as a criterion to discriminate the two thermodynamic approaches introduced in ref. https://www.doi.org/10.1103/PhysRevD.92.124069 and our result seems to support the approach which introduces a new thermodynamic parameter R=r{sub 0}.

Preliminary application of SPECT three dimensional brain imaging in normal controls and patients with cerebral infarction

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Zhaosheng, Luan; Pengyong,; Xiqin, Sun; Wei, Wang; Huisheng, Liu; Wen, Zhou [88 Hospital PLA, Taian, SD (China). Dept. of Nuclear Medicine

1992-11-01

10 normal controls and 32 cerebral infarction patients were examined with SPECT three-dimensional (3D) and sectional imaging. The result shows that 3D brain imaging has significant value in the diagnosis of cerebral infarction. 3D brain imaging is superior to sectional imaging in determining the location and size of superficial lesions. For the diagnosis of deep lesions, it is better to combine 3D brain imaging with sectional imaging. The methodology of 3D brain imaging is also discussed.

Preliminary application of SPECT three dimensional brain imaging in normal controls and patients with cerebral infarction

International Nuclear Information System (INIS)

Luan Zhaosheng; Pengyong; Sun Xiqin; Wang Wei; Liu Huisheng; Zhou Wen

1992-01-01

10 normal controls and 32 cerebral infarction patients were examined with SPECT three-dimensional (3D) and sectional imaging. The result shows that 3D brain imaging has significant value in the diagnosis of cerebral infarction. 3D brain imaging is superior to sectional imaging in determining the location and size of superficial lesions. For the diagnosis of deep lesions, it is better to combine 3D brain imaging with sectional imaging. The methodology of 3D brain imaging is also discussed

High-throughput isotropic mapping of whole mouse brain using multi-view light-sheet microscopy

Science.gov (United States)

Nie, Jun; Li, Yusha; Zhao, Fang; Ping, Junyu; Liu, Sa; Yu, Tingting; Zhu, Dan; Fei, Peng

2018-02-01

Light-sheet fluorescence microscopy (LSFM) uses an additional laser-sheet to illuminate selective planes of the sample, thereby enabling three-dimensional imaging at high spatial-temporal resolution. These advantages make LSFM a promising tool for high-quality brain visualization. However, even by the use of LSFM, the spatial resolution remains insufficient to resolve the neural structures across a mesoscale whole mouse brain in three dimensions. At the same time, the thick-tissue scattering prevents a clear observation from the deep of brain. Here we use multi-view LSFM strategy to solve this challenge, surpassing the resolution limit of standard light-sheet microscope under a large field-of-view (FOV). As demonstrated by the imaging of optically-cleared mouse brain labelled with thy1-GFP, we achieve a brain-wide, isotropic cellular resolution of 3μm. Besides the resolution enhancement, multi-view braining imaging can also recover complete signals from deep tissue scattering and attenuation. The identification of long distance neural projections across encephalic regions can be identified and annotated as a result.

Applicability of the 3D-VIBE sequence to whole brain imaging

International Nuclear Information System (INIS)

Makabe, Takeshi; Nakamura, Manami; Moriyama, Ryo

2009-01-01

The volumetric interpolated breath-hold examination (VIBE) method has been developed imaging also holds its breath in an abdomen, and to do three-dimensional T1WI in possible time in gradient echo sequence, and applied to dynamic study mainly and planning for time reduction using an interpolation and partial fourier. We considered the condition for imaging to do whole brain as high resolution image using VIBE. Even if base matrix was maintained when an interpolation and partial fourier were used too much excessively by Phantom experiment, the resolution of multiplanar reconstruction (MPR) image fell. There was a limit of the interpolation therefore to maintain the resolution as voxel. Signal-to-noise ratio (SNR) fell by flip angle (FA) increase by the applicability to the head, and peak existed in about 15 deg in contrast-to-noise ratio (CNR) of white matter and gray matter. Therefore by it's clinical and optimizing the imaging condition of VIBE, whole brain, it was imaging possible in about 3 minutes as high resolution image. (author)

The value of whole-brain CT perfusion imaging and CT angiography using a 320-slice CT scanner in the diagnosis of MCI and AD patients

Energy Technology Data Exchange (ETDEWEB)

Zhang, Bo; Gu, Guo-jun; Jiang, Hong; Guo, Yi [Medical School of Tongji University, Department of Medical Imaging, Tongji Hospital, Shanghai (China); Shen, Xing [Traditional Chinese Hospital, Department of Radiology, Kun Shan, Jiangsu Province (China); Li, Bo; Zhang, Wei [Medical School of Jiaotong University, Department of Medical Imaging, Renji Hospital, Shanghai (China)

2017-11-15

To validate the value of whole-brain computed tomography perfusion (CTP) and CT angiography (CTA) in the diagnosis of mild cognitive impairment (MCI) and Alzheimer's disease (AD). Whole-brain CTP and four-dimensional CT angiography (4D-CTA) images were acquired in 30 MCI, 35 mild AD patients, 35 moderate AD patients, 30 severe AD patients and 50 normal controls (NC). Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and correlation between CTP and 4D-CTA were analysed. Elevated CBF in the left frontal and temporal cortex was found in MCI compared with the NC group. However, TTP was increased in the left hippocampus in mild AD patients compared with NC. In moderate and severe AD patients, hypoperfusion was found in multiple brain areas compared with NC. Finally, we found that the extent of arterial stenosis was negatively correlated with CBF in partial cerebral cortex and hippocampus, and positively correlated with TTP in these areas of AD and MCI patients. Our findings suggest that whole-brain CTP and 4D-CTA could serve as a diagnostic modality in distinguishing MCI and AD, and predicting conversion from MCI based on TTP of left hippocampus. (orig.)

The value of whole-brain CT perfusion imaging and CT angiography using a 320-slice CT scanner in the diagnosis of MCI and AD patients

International Nuclear Information System (INIS)

Zhang, Bo; Gu, Guo-jun; Jiang, Hong; Guo, Yi; Shen, Xing; Li, Bo; Zhang, Wei

2017-01-01

To validate the value of whole-brain computed tomography perfusion (CTP) and CT angiography (CTA) in the diagnosis of mild cognitive impairment (MCI) and Alzheimer's disease (AD). Whole-brain CTP and four-dimensional CT angiography (4D-CTA) images were acquired in 30 MCI, 35 mild AD patients, 35 moderate AD patients, 30 severe AD patients and 50 normal controls (NC). Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and correlation between CTP and 4D-CTA were analysed. Elevated CBF in the left frontal and temporal cortex was found in MCI compared with the NC group. However, TTP was increased in the left hippocampus in mild AD patients compared with NC. In moderate and severe AD patients, hypoperfusion was found in multiple brain areas compared with NC. Finally, we found that the extent of arterial stenosis was negatively correlated with CBF in partial cerebral cortex and hippocampus, and positively correlated with TTP in these areas of AD and MCI patients. Our findings suggest that whole-brain CTP and 4D-CTA could serve as a diagnostic modality in distinguishing MCI and AD, and predicting conversion from MCI based on TTP of left hippocampus. (orig.)

Barrier mechanisms in the Drosophila blood-brain barrier

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Samantha Jane Hindle

2014-12-01

Full Text Available The invertebrate blood-brain barrier field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through GPCR signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate blood-brain barrier has recently been shown to require coordinated function of all layers of the compound barrier structure, analogous to signaling between the layers of the vertebrate neurovascular unit. These findings strengthen the notion that many blood-brain barrier mechanisms are conserved between vertebrates and invertebrates, and suggest that novel findings in invertebrate model organisms will have a significant impact on the understanding of vertebrate BBB functions. In this vein, important roles in coordinating localized and systemic signaling to dictate organism development and growth are beginning to show how the blood-brain barrier can govern whole animal physiologies. This includes novel functions of blood-brain barrier gap junctions in orchestrating synchronized neuroblast proliferation, and of blood-brain barrier secreted antagonists of insulin receptor signaling. These advancements and others are pushing the field forward in exciting new directions. In this review, we provide a synopsis of invertebrate blood-brain barrier anatomy and physiology, with a focus on insights from the past 5 years, and highlight important areas for future study.

Generalized Uncertainty Principle and Black Hole Entropy of Higher-Dimensional de Sitter Spacetime

International Nuclear Information System (INIS)

Zhao Haixia; Hu Shuangqi; Zhao Ren; Li Huaifan

2007-01-01

Recently, there has been much attention devoted to resolving the quantum corrections to the Bekenstein-Hawking black hole entropy. In particular, many researchers have expressed a vested interest in the coefficient of the logarithmic term of the black hole entropy correction term. In this paper, we calculate the correction value of the black hole entropy by utilizing the generalized uncertainty principle and obtain the correction term caused by the generalized uncertainty principle. Because in our calculation we think that the Bekenstein-Hawking area theorem is still valid after considering the generalized uncertainty principle, we derive that the coefficient of the logarithmic term of the black hole entropy correction term is positive. This result is different from the known result at present. Our method is valid not only for four-dimensional spacetimes but also for higher-dimensional spacetimes. In the whole process, the physics idea is clear and calculation is simple. It offers a new way for studying the entropy correction of the complicated spacetime.

New three-dimensional moving field radiation therapy for brain tumors

Energy Technology Data Exchange (ETDEWEB)

Mitsuyama, Fuyuki; Kanno, Tetsuo; Nagata, Yutaka; Koga, Sukehiko [Fujita-Gakuen Health Univ., Toyoake, Aichi (Japan); Jain, V K

1992-06-01

A new modified rotation radiation method called 'three-dimensional moving field radiation therapy' is described. The new method uses rotation in many planes while maintaining the same isocenter to achieve a good spatial dose distribution. This delivers a high dose to tumors and spares the surrounding normal structures. This easy method can be carried out using the equipment for conventional rotation radiation therapy. The new method was superior to the one plane rotation radiation therapy using a physical phantom with film, a chemical phantom using the iodine-starch reaction, and a new biological model using tumor cells. Treatment of six brain tumors irradiated with total air doses of 50-60 Gy caused no hair loss or radiation necrosis. (author).

Three-dimensional multispectral optoacoustic mesoscopy reveals melanin and blood oxygenation in human skin in vivo.

Science.gov (United States)

Schwarz, Mathias; Buehler, Andreas; Aguirre, Juan; Ntziachristos, Vasilis

2016-01-01

Optical imaging plays a major role in disease detection in dermatology. However, current optical methods are limited by lack of three-dimensional detection of pathophysiological parameters within skin. It was recently shown that single-wavelength optoacoustic (photoacoustic) mesoscopy resolves skin morphology, i.e. melanin and blood vessels within epidermis and dermis. In this work we employed illumination at multiple wavelengths for enabling three-dimensional multispectral optoacoustic mesoscopy (MSOM) of natural chromophores in human skin in vivo operating at 15-125 MHz. We employ a per-pulse tunable laser to inherently co-register spectral datasets, and reveal previously undisclosed insights of melanin, and blood oxygenation in human skin. We further reveal broadband absorption spectra of specific skin compartments. We discuss the potential of MSOM for label-free visualization of physiological biomarkers in skin in vivo. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of three glucometers for whole blood glucose measurements at the point of care in preterm or low-birth-weight infants

OpenAIRE

Hwang, Joon Ho; Sohn, Yong-Hak; Chang, Seong-Sil; Kim, Seung Yeon

2015-01-01

Purpose We evaluated three blood glucose self-monitoring for measuring whole blood glucose levels in preterm and low-birth-weight infants. Methods Between December 1, 2012 and March 31, 2013, 230 blood samples were collected from 50 newborns, who weighed, ≤2,300 g or were ≤36 weeks old, in the the neonatal intensive care unit of Eulji University Hospital. Three blood glucose self-monitoring (A: Precision Pcx, Abbott; B: One-Touch Verio, Johnson & Johnson; C: LifeScan SureStep Flexx, Johnson &...

[Identification of Animal Whole Blood Based on Near Infrared Transmission Spectroscopy].

Science.gov (United States)

Wan, Xiong; Wang, Jian; Liu, Peng-xi; Zhang, Ting-ting

2016-01-01

The inspection and classification for blood products are important but complicated in import-export ports or inspection and quarantine departments. For the inspection of whole blood products, open sampling can cause pollution and virulence factors in bloods samples may even endanger inspectors. Thus non-contact classification and identification methods for whole bloods of animals are needed. Spectroscopic techniques adopted in the flowcytometry need sampling blood cells during the detection; therefore they can not meet the demand of non-contact identification and classification for whole bloods of animals. Infrared absorption spectroscopy is a technique that can be used to analyze the molecular structure and chemical bonds of detected samples under the condition of non-contact. To find a feasible spectroscopic approach of non-contact detection for the species variation in whole blood samples, a near infrared transmitted spectra (NITS, 4 497.669 - 7 506.4 cm(-1)) experiment of whole blood samples of three common animals including chickens, dogs and cats has been conducted. During the experiment, the spectroscopic resolution is 5 cm(-1), and each spectrogram is an average of 5 measured spectral data. Experimental results show that all samples have a sharp absorption peak between 5 184 and 5 215 cm(-1), and a gentle absorption peak near 7 000 cm(-1). Besides, the NITS curves of different samples of same animals are similar, and only have slight differences in the whole transmittance. A correlation coefficient (CC) is induced to distinguish the differences of the three animals' whole bloods in NITS curves, and the computed CCs between NITS curves of different samples of the same animals, are greater than 0.99, whereas CCs between NITS curves of the whole bloods of different animals are from 0.509 48 to 0.916 13. Among which CCs between NITS curves of the whole bloods of chickens and cats are from 0.857 23 to 0.912 44, CCs between NITS curves of the whole bloods of

Three-dimensional image reconstruction from stereo DSA

International Nuclear Information System (INIS)

Sakamoto, Kiyoshi; Kotoura, Noriko; Umehara, Takayoshi; Yamada, Eiji; Inaba, Tomohiro; Itou, Hiroshi

1999-01-01

The technique of interventional radiology has spread rapidly in recent years, and three-dimensional information from blood vessel images is being sought to enhance examinations. Stereo digital subtraction angiography (DSA) and rotational DSA were developed for that purpose. However, it is difficult with stereo DSA to observe the image pair during examination and to obtain positional information on blood vessels. Further, the exposure dose is increased in rotational DSA when many mask images need to be collected, and the patient is required to hold his or her breath for a long duration. We therefore devised a technique to construct three-dimensional blood vessel images by employing geometrical information extracted from stereo DSA images using the right and left images. We used a judgment method based on the correlation coefficient, although we had to extract an equal blood vessel from the right and left images to determine the three-dimensional coordinates of the blood vessel. The reconstructed three-dimensional blood vessels were projected from various angles, again by using a virtual focus, and new images were created. These image groups were displayed as rotational images by the animation display function incorporated in the DSA device. This system can observe blood vessel images of the same phase at a free angle, although the image quality is inferior to that of rotational DSA. In addition, because collection of the mask images is reduced, exposure dose can be decreased. Further, the system offers enhanced safety because no mechanical movement of the imaging system is involved. (author)

Effects of emotional valence and three-dimensionality of visual stimuli on brain activation: an fMRI study.

Science.gov (United States)

Dores, A R; Almeida, I; Barbosa, F; Castelo-Branco, M; Monteiro, L; Reis, M; de Sousa, L; Caldas, A Castro

2013-01-01

Examining changes in brain activation linked with emotion-inducing stimuli is essential to the study of emotions. Due to the ecological potential of techniques such as virtual reality (VR), inspection of whether brain activation in response to emotional stimuli can be modulated by the three-dimensional (3D) properties of the images is important. The current study sought to test whether the activation of brain areas involved in the emotional processing of scenarios of different valences can be modulated by 3D. Therefore, the focus was made on the interaction effect between emotion-inducing stimuli of different emotional valences (pleasant, unpleasant and neutral valences) and visualization types (2D, 3D). However, main effects were also analyzed. The effect of emotional valence and visualization types and their interaction were analyzed through a 3 × 2 repeated measures ANOVA. Post-hoc t-tests were performed under a ROI-analysis approach. The results show increased brain activation for the 3D affective-inducing stimuli in comparison with the same stimuli in 2D scenarios, mostly in cortical and subcortical regions that are related to emotional processing, in addition to visual processing regions. This study has the potential of clarify brain mechanisms involved in the processing of emotional stimuli (scenarios' valence) and their interaction with three-dimensionality.

A three-dimensional stereotaxic atlas of the gray short-tailed opossum (Monodelphis domestica) brain.

Science.gov (United States)

Majka, Piotr; Chlodzinska, Natalia; Turlejski, Krzysztof; Banasik, Tomasz; Djavadian, Ruzanna L; Węglarz, Władysław P; Wójcik, Daniel K

2018-05-01

The gray short-tailed opossum (Monodelphis domestica) is a small marsupial gaining recognition as a laboratory animal in biomedical research. Despite numerous studies on opossum neuroanatomy, a consistent and comprehensive neuroanatomical reference for this species is still missing. Here we present the first three-dimensional, multimodal atlas of the Monodelphis opossum brain. It is based on four complementary imaging modalities: high resolution ex vivo magnetic resonance images, micro-computed tomography scans of the cranium, images of the face of the cutting block, and series of sections stained with the Nissl method and for myelinated fibers. Individual imaging modalities were reconstructed into a three-dimensional form and then registered to the MR image by means of affine and deformable registration routines. Based on a superimposition of the 3D images, 113 anatomical structures were demarcated and the volumes of individual regions were measured. The stereotaxic coordinate system was defined using a set of cranial landmarks: interaural line, bregma, and lambda, which allows for easy expression of any location within the brain with respect to the skull. The atlas is released under the Creative Commons license and available through various digital atlasing web services.

Three-dimensional analysis of facial morphology in Brazilian population with Caucasian, Asian, and Black ethnicity

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Ana Maria Bettoni Rodrigues da Silva

2017-01-01

Full Text Available Aim: To compare facial features related to the nose, lips and face between the Caucasian, Asian, and Black ethnicity in the Brazilian population by means of linear measurements and proportion indices obtained from the analysis of three-dimensional (3D images taken by 3D stereophotogrammetry. Materials and Methods: Thirty healthy subjects, being 10 Caucasians, 10 Blacks and 10 Asians had reference points (landmarks demarcated on their faces, 3D images were obtained (Vectra M3 and the following measurements were calculated: Facial proportion indices relative to the nose, lips and face. The statistical analysis was performed comparing the ethnic groups (one-way analysis of variance. Results: The Blacks and Asians showed the greatest difference in the face analysis (width, height of the lower face, upper face index and lower face index – P < 0.05. In the comparisons between groups, differences were verified to the mouth width and lower lip vermilion height. In the nose analysis, the biggest differences were obtained for the proportion indices, being that Caucasians versus Asians and Caucasians versus Blacks have showed the largest differences. Conclusion: This study found the presence of some similarities in the proportion indices of nose, lips and face between the ethnic groups of the Brazilian population, as well as some important differences that should be known to guide surgical and forensics procedures, among others.

Albumin extravasation in bicuculline-induced blood-brain barrier dysfunction

International Nuclear Information System (INIS)

Persson, L.I.; Rosengren, L.E.; Johansson, B.B.

1980-01-01

The extravasation of endogeneous rat albumin and exogeneous 125 I-labeled human serum albumin was compared in rats subjected to bicuculline-induced blood-brain barrier dysfunction. The correlation between rocket immunoelectrophoretic assays of endogeneous rat albumin and 125 I-labeled human serum albumin, assayed by gamma scintillation counting, was good irrespective of whether 125 I-labeled albumin was studied in whole brain tissue or in brain homogenates. The ratio of brain to serum albumin was similar with the two assay methods. (author)

Late effects of whole brain irradiation within the therapeutic range

International Nuclear Information System (INIS)

Caveness, W.F.; Carsten, A.L.

1978-01-01

Whole brain exposure with supervoltage x irradiation was carried out in three sets of Macaca mulatta. Two sets of 12 monkeys each, at puberty, received single and fractionated exposures, respectively. One set of 21 monkeys in adulthood received a fractionated exposure. Exposure to 1000 rads in a single dose, at puberty, caused no late effects. Exposure to 1500 rads caused small areas of necrosis in the forebrain white matter at 26 weeks, but a much more extensive involvement at and beyond 52 weeks that included confluent areas of necrosis in gray and white matter. Brain loss resulted in ventricular dilatation. Gliomas appeared in two out of three monkeys at or beyond 52 weeks. Exposure to 2000 rads caused such a wide scatter of focal areas of necrosis, including those in the brain stem, that survival beyond 20 to 26 weeks was not possible. All showed enlarged ventricular systems. Whole brain exposure, 200 rads a day, five days a week, for a course of 4000 rads, at puberty, resulted in no delayed effects. Whole brain exposure to 6000 rads in a six weeks course, in the adult, produced less effects than the same dose at puberty. The onset of the scattered necrotic lesions was later than expected, appearing in one out of three animals at 33 weeks, two out of three animals at 52 weeks, and two out of three at 104 weeks. The lesions at 104 weeks were predominantly mineralized, but were accompanied by a greater extent of telangiectasia than seen in the pubescent monkeys

Effect of 60Co γ-ray irradiation on cytoskeleton of human peripheral blood monocytes with whole mount cell electron microscopy in vitro

International Nuclear Information System (INIS)

Chen Xiaomei; Guo Yuhua; Yin Zhiwei

1992-01-01

Whole mount cell electron microscopy was used in combination with selective extraction to prepare cytoskeletal framework. Cytoskeleton prepared by Triton X-100 treatment of human peripheral blood monocytes appeared on electron microscopy as a highly organized and interconnected three-dimensional matrix of different fibrous elements. By three-dimensional visualization of Triton X-100 resistant cytoskeletons it was demonstrated that different doses of 60 Co γ-rays caused distinctive and reproducible alterations of the cytoskeleton of intact human peripheral blood monocytes in vitro. The alterations were similar to those caused by cytochalasin B and by colchicine. From these observations and other workers'studies, it is presumed that 60 Co γ-ray irradiation may inhibit cytoplasmic microtubule and microfilament assembling

A Thomistic defense of whole-brain death.

Science.gov (United States)

Eberl, Jason T

2015-08-01

Michel Accad critiques the currently accepted whole-brain criterion for determining the death of a human being from a Thomistic metaphysical perspective and, in so doing, raises objections to a particular argument defending the whole-brain criterion by Patrick Lee and Germain Grisez. In this paper, I will respond to Accad's critique of the whole-brain criterion and defend its continued validity as a criterion for determining when a human being's death has occurred in accord with Thomistic metaphysical principles. I will, however, join Accad in criticizing Lee and Grisez's proposed defense of the whole-brain criterion as potentially leading to erroneous conclusions regarding the determination of human death. Lay summary: Catholic physicians and bioethicists currently debate the legally accepted clinical standard for determining when a human being has died-known as the "wholebrain criterion"-which has also been morally affirmed by the Magisterium. This paper responds to physician Michel Accad's critique of the whole-brain criterion based upon St. Thomas Aquinas's metaphysical account of human nature as a union of a rational soul and a material body. I defend the whole-brain criterion from the same Thomistic philosophical perspective, while agreeing with Accad's objection to an alternative Thomistic defense of whole-brain death by philosophers Patrick Lee and Germain Grisez.

Performance, Accuracy and Efficiency Evaluation of a Three-Dimensional Whole-Core Neutron Transport Code AGENT

International Nuclear Information System (INIS)

Jevremovic, Tatjana; Hursin, Mathieu; Satvat, Nader; Hopkins, John; Xiao, Shanjie; Gert, Godfree

2006-01-01

The AGENT (Arbitrary Geometry Neutron Transport) an open-architecture reactor modeling tool is deterministic neutron transport code for two or three-dimensional heterogeneous neutronic design and analysis of the whole reactor cores regardless of geometry types and material configurations. The AGENT neutron transport methodology is applicable to all generations of nuclear power and research reactors. It combines three theories: (1) the theory of R-functions used to generate real three-dimensional whole-cores of square, hexagonal or triangular cross sections, (2) the planar method of characteristics used to solve isotropic neutron transport in non-homogenized 2D) reactor slices, and (3) the one-dimensional diffusion theory used to couple the planar and axial neutron tracks through the transverse leakage and angular mesh-wise flux values. The R-function-geometrical module allows a sequential building of the layers of geometry and automatic sub-meshing based on the network of domain functions. The simplicity of geometry description and selection of parameters for accurate treatment of neutron propagation is achieved through the Boolean algebraic hierarchically organized simple primitives into complex domains (both being represented with corresponding domain functions). The accuracy is comparable to Monte Carlo codes and is obtained by following neutron propagation through real geometrical domains that does not require homogenization or simplifications. The efficiency is maintained through a set of acceleration techniques introduced at all important calculation levels. The flux solution incorporates power iteration with two different acceleration techniques: Coarse Mesh Re-balancing (CMR) and Coarse Mesh Finite Difference (CMFD). The stand-alone originally developed graphical user interface of the AGENT code design environment allows the user to view and verify input data by displaying the geometry and material distribution. The user can also view the output data such

Three-dimensional black blood MR angiography of the liver during breath holding. A comparison with two-dimensional time-of-flight MR angiography

International Nuclear Information System (INIS)

Suto, Y.; Ohuchi, Y.; Kimura, T.; Shirakawa, T.; Mizuuchi, N.; Takizawa, O.; Yamane, T.; Kamba, M.; Moriyama, S.; Ohta, Y.

1994-01-01

In 2-D time-of-flight MR angiography (2-D TOF MRA) of the liver, artifacts caused by respiratory motion are unavoidable. Therefore, a 3-D black blood MRA of the liver was attempted in 7 healthy volunteers, using a 3-D gradient echo sequence which allows imaging during breath holding. 2-D TOF MRA was performed as well. In all subjects, 3-D MRA allowed visualization of the trunk, 1st-, and 2nd-order branches of the portal vein without interruption. Right 3rd-order branches were visualized without interruption in 6 of 7 subjects (85%). However, with 2-D MRA, the transverse portion of the left main portal vein could not be visualized in any subject, and the periphery of the portal vein was less clear than with 3-D MRA. (orig.)

Quantitative analysis of normal fetal brain volume and flow by three-dimensional power Doppler ultrasound

Directory of Open Access Journals (Sweden)

Ju-Chun Hsu

2013-09-01

Conclusion: 3D ultrasound can be used to assess the fetal brain volume and blood flow development quantitatively. Our study indicates that the fetal brain vascularization and blood flow correlates significantly with the advancement of GA. This information may serve as a reference point for further studies of the fetal brain volume and blood flow in abnormal conditions.

Clinical application of RapidArc volumetric modulated arc therapy as a component in whole brain radiation therapy for poor prognostic, four or more multiple brain metastases

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung Heon; Lee, Kyu Chan; Choi, Jin Ho; Kim, Hye Young; Lee, Seok Ho; Sung, Ki Hoon; Kim, Yun Mi [Gachon University Gil Hospital, Incheon (Korea, Republic of)

2012-06-15

To determine feasibility of RapidArc in sequential or simultaneous integrated tumor boost in whole brain radiation therapy (WBRT) for poor prognostic patients with four or more brain metastases. Nine patients with multiple ({>=}4) brain metastases were analyzed. Three patients were classified as class II in recursive partitioning analysis and 6 were class III. The class III patients presented with hemiparesis, cognitive deficit, or apraxia. The ratio of tumor to whole brain volume was 0.8-7.9%. Six patients received 2-dimensional bilateral WBRT, (30 Gy/10- 12 fractions), followed by sequential RapidArc tumor boost (15-30 Gy/4-10 fractions). Three patients received RapidArc WBRT with simultaneous integrated boost to tumors (48-50 Gy) in 10-20 fractions. The median biologically effective dose to metastatic tumors was 68.1 Gy10 and 67.2 Gy10 and the median brain volume irradiated more than 100 Gy3 were 1.9% (24 cm3) and 0.8% (13 cm3) for each group. With less than 3 minutes of treatment time, RapidArc was easily applied to the patients with poor performance status. The follow-up period was 0.3-16.5 months. Tumor responses among the 6 patients who underwent follow-up magnetic resonance imaging were partial and stable in 3 and 3, respectively. Overall survival at 6 and 12 months were 66.7% and 41.7%, respectively. The local progression-free survival at 6 and 12 months were 100% and 62.5%, respectively. RapidArc as a component in whole brain radiation therapy for poor prognostic, multiple brain metastases is an effective and safe modality with easy application.

World-volume effective theory for higher-dimensional black holes.

Science.gov (United States)

Emparan, Roberto; Harmark, Troels; Niarchos, Vasilis; Obers, Niels A

2009-05-15

We argue that the main feature behind novel properties of higher-dimensional black holes, compared to four-dimensional ones, is that their horizons can have two characteristic lengths of very different size. We develop a long-distance world-volume effective theory that captures the black hole dynamics at scales much larger than the short scale. In this limit the black hole is regarded as a blackfold: a black brane (possibly boosted locally) whose world volume spans a curved submanifold of the spacetime. This approach reveals black objects with novel horizon geometries and topologies more complex than the black ring, but more generally it provides a new organizing framework for the dynamics of higher-dimensional black holes.

An automatic extraction algorithm of three dimensional shape of brain parenchyma from MR images

International Nuclear Information System (INIS)

Matozaki, Takeshi

2000-01-01

For the simulation of surgical operations, the extraction of the selected region using MR images is useful. However, this segmentation requires a high level of skill and experience from the technicians. We have developed an unique automatic extraction algorithm for extracting three dimensional brain parenchyma using MR head images. It is named the ''three dimensional gray scale clumsy painter method''. In this method, a template having the shape of a pseudo-circle, a so called clumsy painter (CP), moves along the contour of the selected region and extracts the region surrounded by the contour. This method has advantages compared with the morphological filtering and the region growing method. Previously, this method was applied to binary images, but there were some problems in that the results of the extractions were varied by the value of the threshold level. We introduced gray level information of images to decide the threshold, and depend upon the change of image density between the brain parenchyma and CSF. We decided the threshold level by the vector of a map of templates, and changed the map according to the change of image density. As a result, the over extracted ratio was improved by 36%, and the under extracted ratio was improved by 20%. (author)

Using a Microfluidic-Microelectric Device to Directly Separate Serum/Blood Cells from a Continuous Whole Bloodstream Flow

Science.gov (United States)

Wang, Ming-Wen; Jeng, Kuo-Shyang; Yu, Ming-Che; Su, Jui-Chih

2012-03-01

To make the rapid separation of serum/blood cells possible in a whole bloodstream flow without centrifugation and Pasteur pipette suction, the first step is to use a microchannel to transport the whole bloodstream into a microdevice. Subsequently, the resulting serum/blood cell is separated from the whole bloodstream by applying other technologies. Creating the serum makes this subsequent separation possible. To perform the actual separation, a microchannel with multiple symmetric curvilinear microelectrodes has been designed on a glass substrate and fabricated with micro-electromechanical system technology. The blood cells can be observed clearly by black-field microscopy imaging. A local dielectrophoretic (DEP) force, obtained from nonuniform electric fields, was used for manipulating and separating the blood cells from a continuous whole bloodstream. The experimental studies show that the blood cells incur a local dielectrophoretic field when they are suspended in a continuous flow (v = 0.02-0.1 cm/s) and exposed to AC fields at a frequency of 200 kHz. Using this device, the symmetric curvilinear microelectrodes provide a local dielectrophoretic field that is sufficiently strong for separating nearby blood cells and purifying the serum in a continuous whole bloodstream flow.

Disposable glucose test strip for whole blood with integrated sensing/diffusion-limiting layer

Energy Technology Data Exchange (ETDEWEB)

Chen Zhencheng [Department of Biomedical Engineering, School of Info-Physics and Geomatics Engineering, Central South University, Changsha 410083 (China); Fang Cheng, E-mail: fangpingchuan@163.co [Department of Biomedical Engineering, School of Info-Physics and Geomatics Engineering, Central South University, Changsha 410083 (China); Wang Hongyan; He Jishan [Department of Biomedical Engineering, School of Info-Physics and Geomatics Engineering, Central South University, Changsha 410083 (China)

2009-12-30

A disposable glucose test strip with an integrated sensing/diffusion-limiting layer was developed. A formulation containing filler, glucose oxidase and electronic mediator was screen-printed over two carbon electrodes to form an integrated sensing/diffusion-limiting layer. On rehydration, the integrated layer does not break up, but swells to form a gelled and three-dimensional meshy reaction zone on the surface of the underlying conductive elements in which reactants and mediator move freely, but interfering species such as red blood cells containing oxygenated hemoglobin are excluded. On the same time, the integrated layer maintains a rate of permeation of the analyte through it with a variation of less than 10% at temperatures ranging from 15 deg. C to 42 deg. C. This biosensor is substantially insensitive to interferents and essentially independent to relevant temperature, which provides a more reliable reading of actual blood glucose value in human whole blood.

Detection of endotoxins and other pyrogens using human whole blood.

Science.gov (United States)

Fennrich, S; Fischer, M; Hartung, T; Lexa, P; Montag-Lessing, T; Sonntag, H G; Weigandt, M; Wendel, A

1999-01-01

When cells of the immune system, i.e. primarily blood monocytes and macrophages, come into contact with pyrogens (fever-inducing contaminations) they release mediators transmitting the fever reaction through the organism to the thermoregulatory centres of the brain. The new test discussed here exploits this reaction for the detection of pyrogens: human whole blood taken from healthy volunteers is incubated in the presence of the test sample. If there is pyrogen contamination, the endogenous pyrogen interleukin-1 is released, which is then determined by ELISA. According to the pharmacopoeia, the rabbit pyrogen test determines the fever reaction following injection of a test sample. In comparison, the new whole blood assay is more sensitive, less expensive and determines the reaction of the targeted species. Compared to the well established in vitro alternative, i.e. the limulus amebocyte lysate assay (LAL), the new blood assay is not restricted to endotoxins of gram-negative bacteria, it is not affected by endotoxin-binding blood proteins and it reflects the potency of different endotoxin preparations in mammals. Here, interim results of the ongoing optimization and pre-validation are reported and the present state of the evaluation for biological and pharmaceutical drugs are presented.

Gribov ambiguity in asymptotically AdS three-dimensional gravity

International Nuclear Information System (INIS)

Anabalon, Andres; Canfora, Fabrizio; Giacomini, Alex; Oliva, Julio

2011-01-01

In this paper the zero modes of the de Donder gauge Faddeev-Popov operator for three-dimensional gravity with negative cosmological constant are analyzed. It is found that the AdS 3 vacuum produces (infinitely many) normalizable smooth zero modes of the Faddeev-Popov operator. On the other hand, it is found that the Banados-Teitelboim-Zanelli black hole (including the zero mass black hole) does not generate zero modes. This differs from the usual Gribov problem in QCD where, close to the maximally symmetric vacuum, the Faddeev-Popov determinant is positive definite while 'far enough' from the vacuum it can vanish. This suggests that the zero mass Banados-Teitelboim-Zanelli black hole could be a suitable ground state of three-dimensional gravity with negative cosmological constant. Because of the kinematic origin of this result, it also applies for other covariant gravity theories in three dimensions with AdS 3 as maximally symmetric solution, such as new massive gravity and topologically massive gravity. The relevance of these results for supersymmetry breaking is pointed out.

Five-dimensional rotating black hole in a uniform magnetic field: The gyromagnetic ratio

International Nuclear Information System (INIS)

Aliev, A.N.; Frolov, Valeri P.

2004-01-01

In four-dimensional general relativity, the fact that a Killing vector in a vacuum spacetime serves as a vector potential for a test Maxwell field provides one with an elegant way of describing the behavior of electromagnetic fields near a rotating Kerr black hole immersed in a uniform magnetic field. We use a similar approach to examine the case of a five-dimensional rotating black hole placed in a uniform magnetic field of configuration with biazimuthal symmetry that is aligned with the angular momenta of the Myers-Perry spacetime. Assuming that the black hole may also possess a small electric charge we construct the five-vector potential of the electromagnetic field in the Myers-Perry metric using its three commuting Killing vector fields. We show that, like its four-dimensional counterparts, the five-dimensional Myers-Perry black hole rotating in a uniform magnetic field produces an inductive potential difference between the event horizon and an infinitely distant surface. This potential difference is determined by a superposition of two independent Coulomb fields consistent with the two angular momenta of the black hole and two nonvanishing components of the magnetic field. We also show that a weakly charged rotating black hole in five dimensions possesses two independent magnetic dipole moments specified in terms of its electric charge, mass, and angular momentum parameters. We prove that a five-dimensional weakly charged Myers-Perry black hole must have the value of the gyromagnetic ratio g=3

Creation and evaluation of complementary composite three-dimensional image in various brain diseases. An application of three-dimensional brain SPECT image and three-dimensional CT image

International Nuclear Information System (INIS)

Seiki, Yoshikatsu; Shibata, Iekado; Mito, Toshiaki; Sugo, Nobuo

2000-01-01

The purpose of this study was to develop 3D composite images for use in functional and anatomical evaluation of various cerebral pathologies. Imaging studies were performed in normal volunteers, patients with hydrocephalus and patients with brain tumor (meningioma and metastatic tumor) using a three-detector SPECT system (Prism 3000) and helical CT scanner (Xvigor). 123 I-IMP was used in normal volunteers and patients with hydrocephalus, and 201 TLCL in patients with brain tumor. An Application Visualization System-Medical Viewer (AVS-MV) was used on a workstation (Titan 2) to generate 3D images. A new program was developed by synthesizing surface rendering and volume rendering techniques. The clinical effects of shunt operations were successfully evaluated in patients with hydrocephalus by means of translucent 3D images of the deep brain. Changes in the hypoperfusion area around the cerebral ventricle were compared with morphological changes in the cerebral ventricle on CT. In addition to the information concerning the characteristics of brain tumors and surrounding edemas, hemodynamic changes and changeable hypoperfusion areas around the tumors were visualized on 3D composite CT and SPECT images. A new method of generating 3D composite images of CT and SPECT was developed by combining graphic data from different systems on the same workstation. Complementary 3D composite images facilitated quantitative analysis of brain volume and functional analysis in various brain diseases. (author)

Development of three-dimensional brain arteriovenous malformation model for patient communication and young neurosurgeon education.

Science.gov (United States)

Dong, Mengqi; Chen, Guangzhong; Qin, Kun; Ding, Xiaowen; Zhou, Dong; Peng, Chao; Zeng, Shaojian; Deng, Xianming

2018-01-15

Rapid prototyping technology is used to fabricate three-dimensional (3D) brain arteriovenous malformation (AVM) models and facilitate presurgical patient communication and medical education for young surgeons. Two intracranial AVM cases were selected for this study. Using 3D CT angiography or 3D rotational angiography images, the brain AVM models were reconstructed on personal computer and the rapid prototyping process was completed using a 3D printer. The size and morphology of the models were compared to brain digital subtraction arteriography of the same patients. 3D brain AVM models were used for preoperative patient communication and young neurosurgeon education. Two brain AVM models were successfully produced. By neurosurgeons' evaluation, the printed models have high fidelity with the actual brain AVM structures of the patients. The patient responded positively toward the brain AVM model specific to himself. Twenty surgical residents from residency programs tested the brain AVM models and provided positive feedback on their usefulness as educational tool and resemblance to real brain AVM structures. Patient-specific 3D printed models of brain AVM can be constructed with high fidelity. 3D printed brain AVM models are proved to be helpful in preoperative patient consultation, surgical planning and resident training.

Thermodynamics of higher dimensional black holes

International Nuclear Information System (INIS)

Accetta, F.S.; Gleiser, M.

1986-05-01

We discuss the thermodynamics of higher dimensional black holes with particular emphasis on a new class of spinning black holes which, due to the increased number of Casimir invariants, have additional spin degrees of freedom. In suitable limits, analytic solutions in arbitrary dimensions are presented for their temperature, entropy, and specific heat. In 5 + 1 and 9 + 1 dimensions, more general forms for these quantities are given. It is shown that the specific heat for a higher dimensional black hole is negative definite if it has only one non-zero spin parameter, regardless of the value of this parameter. We also consider equilibrium configurations with both massless particles and massive string modes. 16 refs., 3 figs

Thermodynamics of higher dimensional black holes

Energy Technology Data Exchange (ETDEWEB)

Accetta, F.S.; Gleiser, M.

1986-05-01

We discuss the thermodynamics of higher dimensional black holes with particular emphasis on a new class of spinning black holes which, due to the increased number of Casimir invariants, have additional spin degrees of freedom. In suitable limits, analytic solutions in arbitrary dimensions are presented for their temperature, entropy, and specific heat. In 5 + 1 and 9 + 1 dimensions, more general forms for these quantities are given. It is shown that the specific heat for a higher dimensional black hole is negative definite if it has only one non-zero spin parameter, regardless of the value of this parameter. We also consider equilibrium configurations with both massless particles and massive string modes. 16 refs., 3 figs.

[Blood-brain barrier part III: therapeutic approaches to cross the blood-brain barrier and target the brain].

Science.gov (United States)

Weiss, N; Miller, F; Cazaubon, S; Couraud, P-O

2010-03-01

Over the last few years, the blood-brain barrier has come to be considered as the main limitation for the treatment of neurological diseases caused by inflammatory, tumor or neurodegenerative disorders. In the blood-brain barrier, the close intercellular contact between cerebral endothelial cells due to tight junctions prevents the passive diffusion of hydrophilic components from the bloodstream into the brain. Several specific transport systems (via transporters expressed on cerebral endothelial cells) are implicated in the delivery of nutriments, ions and vitamins to the brain; other transporters expressed on cerebral endothelial cells extrude endogenous substances or xenobiotics, which have crossed the cerebral endothelium, out of the brain and into the bloodstream. Recently, several strategies have been proposed to target the brain, (i) by by-passing the blood-brain barrier by central drug administration, (ii) by increasing permeability of the blood-brain barrier, (iii) by modulating the expression and/or the activity of efflux transporters, (iv) by using the physiological receptor-dependent blood-brain barrier transport, and (v) by creating new viral or chemical vectors to cross the blood-brain barrier. This review focuses on the illustration of these different approaches. Copyright (c) 2009 Elsevier Masson SAS. All rights reserved.

Six-dimensional localized black holes: Numerical solutions

International Nuclear Information System (INIS)

Kudoh, Hideaki

2004-01-01

To test the strong-gravity regime in Randall-Sundrum braneworlds, we consider black holes bound to a brane. In a previous paper, we studied numerical solutions of localized black holes whose horizon radii are smaller than the AdS curvature radius. In this paper, we improve the numerical method and discuss properties of the six-dimensional (6D) localized black holes whose horizon radii are larger than the AdS curvature radius. At a horizon temperature T≅1/2πl, the thermodynamics of the localized black hole undergo a transition with its character changing from a 6D Schwarzschild black hole type to a 6D black string type. The specific heat of the localized black holes is negative, and the entropy is greater than or nearly equal to that of the 6D black strings with the same thermodynamic mass. The large localized black holes show flattened horizon geometries, and the intrinsic curvature of the horizon four-geometry becomes negative near the brane. Our results indicate that the recovery mechanism of lower-dimensional Einstein gravity on the brane works even in the presence of the black holes

Radiosurgery without whole brain radiotherapy in melanoma brain metastases

International Nuclear Information System (INIS)

Grob, J.J.; Regis, J.; Laurans, R.; Delaunay, M.; Wolkenstein, P.; Paul, K.; Souteyrand, P.; Koeppel, M.C.; Murraciole, X.; Perragut, J.C.; Bonerandi, J.J.

1998-01-01

To evaluate the effectiveness of radiosurgery without whole brain radiotherapy in the palliative treatment of melanoma brain metastases, we retrospectively assessed the results in 35 patients: 4 with a solitary brain metastasis, 13 with a single brain metastasis and metastases elsewhere and 18 with multiple brain metastases. The local control rate was 98.2% (55/56 metastases) at 3 months. Median survival was 22 months in patients with a solitary brain metastasis, 7.5 months in patients with a single brain metastasis and metastases elsewhere, and 4 months in patients with multiple brain metastases. Complications were unusual and surgery was required in 2 of 35 patients. These results show for the first time that melanoma patients with a unique brain metastasis with or without metastases elsewhere clearly benefit from tumour control easily obtained by radiosurgery. Although the comparison of radiosurgery with surgery and/or whole brain radiotherapy cannot be adequately addressed, radiosurgery alone seems to provide similar results with lower morbidity and impact on quality of life. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

The development and optimisation of 3D black-blood R2* mapping of the carotid artery wall.

Science.gov (United States)

Yuan, Jianmin; Graves, Martin J; Patterson, Andrew J; Priest, Andrew N; Ruetten, Pascal P R; Usman, Ammara; Gillard, Jonathan H

2017-12-01

To develop and optimise a 3D black-blood R 2 * mapping sequence for imaging the carotid artery wall, using optimal blood suppression and k-space view ordering. Two different blood suppression preparation methods were used; Delay Alternating with Nutation for Tailored Excitation (DANTE) and improved Motion Sensitive Driven Equilibrium (iMSDE) were each combined with a three-dimensional (3D) multi-echo Fast Spoiled GRadient echo (ME-FSPGR) readout. Three different k-space view-order designs: Radial Fan-beam Encoding Ordering (RFEO), Distance-Determined Encoding Ordering (DDEO) and Centric Phase Encoding Order (CPEO) were investigated. The sequences were evaluated through Bloch simulation and in a cohort of twenty volunteers. The vessel wall Signal-to-Noise Ratio (SNR), Contrast-to-Noise Ratio (CNR) and R 2 *, and the sternocleidomastoid muscle R 2 * were measured and compared. Different numbers of acquisitions-per-shot (APS) were evaluated to further optimise the effectiveness of blood suppression. All sequences resulted in comparable R 2 * measurements to a conventional, i.e. non-blood suppressed sequence in the sternocleidomastoid muscle of the volunteers. Both Bloch simulations and volunteer data showed that DANTE has a higher signal intensity and results in a higher image SNR than iMSDE. Blood suppression efficiency was not significantly different when using different k-space view orders. Smaller APS achieved better blood suppression. The use of blood-suppression preparation methods does not affect the measurement of R 2 *. DANTE prepared ME-FSPGR sequence with a small number of acquisitions-per-shot can provide high quality black-blood R 2 * measurements of the carotid vessel wall. Copyright © 2017 Elsevier Inc. All rights reserved.

Three-dimensional culture conditions differentially affect astrocyte modulation of brain endothelial barrier function in response to transforming growth factor β1.

Science.gov (United States)

Hawkins, Brian T; Grego, Sonia; Sellgren, Katelyn L

2015-05-22

Blood-brain barrier (BBB) function is regulated by dynamic interactions among cell types within the neurovascular unit, including astrocytes and endothelial cells. Co-culture models of the BBB typically involve astrocytes seeded on two-dimensional (2D) surfaces, which recent studies indicate cause astrocytes to express a phenotype similar to that of reactive astrocytes in situ. We hypothesized that the culture conditions of astrocytes would differentially affect their ability to modulate BBB function in vitro. Brain endothelial cells were grown alone or in co-culture with astrocytes. Astrocytes were grown either as conventional (2D) monolayers, or in a collagen-based gel which allows them to grow in a three-dimensional (3D) construct. Astrocytes were viable in 3D conditions, and displayed a marked reduction in their expression of glial fibrillary acidic protein (GFAP), suggesting reduced activation. Stimulation of astrocytes with transforming growth factor (TGF)β1 decreased transendothelial electrical resistance (TEER) and reduced expression of claudin-5 in co-cultures, whereas treatment of endothelial cells in the absence of astrocytes was without effect. The effect of TGFβ1 on TEER was significantly more pronounced in endothelial cells cultured with 3D astrocytes compared to 2D astrocytes. These results demonstrate that astrocyte culture conditions differentially affect their ability to modulate brain endothelial barrier function, and suggest a direct relationship between reactive gliosis and BBB permeability. Moreover, these studies demonstrate the potential importance of physiologically relevant culture conditions to in vitro modeling of disease processes that affect the neurovascular unit. Copyright © 2015 Elsevier B.V. All rights reserved.

Highly ordered three-dimensional macroporous carbon spheres for determination of heavy metal ions

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yuxiao; Zhang, Jianming [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Liu, Yang, E-mail: yangl@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Huang, Hui [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China)

2012-04-15

Highlights: Black-Right-Pointing-Pointer Highly ordered three dimensional macroporous carbon spheres (MPCSs) were prepared. Black-Right-Pointing-Pointer MPCS was covalently modified by cysteine (MPCS-CO-Cys). Black-Right-Pointing-Pointer MPCS-CO-Cys was first time used in electrochemical detection of heavy metal ions. Black-Right-Pointing-Pointer Heavy metal ions such as Pb{sup 2+} and Cd{sup 2+} can be simultaneously determined. -- Abstract: An effective voltammetric method for detection of trace heavy metal ions using chemically modified highly ordered three dimensional macroporous carbon spheres electrode surfaces is described. The highly ordered three dimensional macroporous carbon spheres were prepared by carbonization of glucose in silica crystal bead template, followed by removal of the template. The highly ordered three dimensional macroporous carbon spheres were covalently modified by cysteine, an amino acid with high affinities towards some heavy metals. The materials were characterized by physical adsorption of nitrogen, scanning electron microscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. High sensitivity was exhibited when this material was used in electrochemical detection (square wave anodic stripping voltammetry) of heavy metal ions due to the porous structure. And the potential application for simultaneous detection of heavy metal ions was also investigated.

First-time whole blood donation: A critical step for donor safety and retention on first three donations.

Science.gov (United States)

Gillet, P; Rapaille, A; Benoît, A; Ceinos, M; Bertrand, O; de Bouyalsky, I; Govaerts, B; Lambermont, M

2015-01-01

Whole blood donation is generally safe although vasovagal reactions can occur (approximately 1%). Risk factors are well known and prevention measures are shown as efficient. This study evaluates the impact of the donor's retention in relation to the occurrence of vasovagal reaction for the first three blood donations. Our study of data collected over three years evaluated the impact of classical risk factors and provided a model including the best combination of covariates predicting VVR. The impact of a reaction at first donation on return rate and complication until the third donation was evaluated. Our data (523,471 donations) confirmed the classical risk factors (gender, age, donor status and relative blood volume). After stepwise variable selection, donor status, relative blood volume and their interaction were the only remaining covariates in the model. Of 33,279 first-time donors monitored over a period of at least 15 months, the first three donations were followed. Data emphasised the impact of complication at first donation. The return rate for a second donation was reduced and the risk of vasovagal reaction was increased at least until the third donation. First-time donation is a crucial step in the donors' career. Donors who experienced a reaction at their first donation have a lower return rate for a second donation and a higher risk of vasovagal reaction at least until the third donation. Prevention measures have to be processed to improve donor retention and provide blood banks with adequate blood supply. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Interactive, three dimensional, CT-based treatment planning of stereotaxic I-125 brain implants. 132

International Nuclear Information System (INIS)

Lulu, B.; Lewis, J.; Smith, V.; Stuart, A.

1987-01-01

Brain implants of I-125 seeds are done with the Brown-Roberts-Wells stereotaxic frame. The patient is CT scanned with the frame bolted to the skull. In the time between the scan and surgery, while the patient is under anesthesia, an interactive three dimensional CT-based treatment plan is performed on a VAX computer. The program is menu driven, easy to use, and easily modifiable. Device dependencies are limited to a small number of subroutines, and an array processor is used to speed dose calculations

Value of black blood T2* cardiovascular magnetic resonance

Directory of Open Access Journals (Sweden)

Carpenter John Paul

2011-03-01

Full Text Available Abstract Purpose To assess whether black blood T2* cardiovascular magnetic resonance is superior to conventional white blood imaging of cardiac iron in patients with thalassaemia major (TM. Materials and methods We performed both conventional white blood and black blood T2* CMR sequences in 100 TM patients to determine intra and inter-observer variability and presence of artefacts. In 23 patients, 2 separate studies of both techniques were performed to assess interstudy reproducibility. Results Cardiac T2* values ranged from 4.5 to 43.8 ms. The mean T2* values were not different between black blood and white blood acquisitions (20.5 vs 21.6 ms, p = 0.26. Compared with the conventional white blood diastolic acquisition, the coefficient of variance of the black blood CMR technique was superior for intra-observer reproducibility (1.47% vs 4.23%, p Conclusions Black blood T2* CMR has superior reproducibility and reduced imaging artefacts for the assessment of cardiac iron, in comparison with the conventional white blood technique, which make it the preferred technique for clinical practice.

A three-dimensional stereotaxic MRI brain atlas of the cichlid fish Oreochromis mossambicus.

Science.gov (United States)

Simões, José M; Teles, Magda C; Oliveira, Rui F; Van der Linden, Annemie; Verhoye, Marleen

2012-01-01

The African cichlid Oreochromis mossambicus (Mozambique tilapia) has been used as a model system in a wide range of behavioural and neurobiological studies. The increasing number of genetic tools available for this species, together with the emerging interest in its use for neurobiological studies, increased the need for an accurate hodological mapping of the tilapia brain to supplement the available histological data. The goal of our study was to elaborate a three-dimensional, high-resolution digital atlas using magnetic resonance imaging, supported by Nissl staining. Resulting images were viewed and analysed in all orientations (transverse, sagittal, and horizontal) and manually labelled to reveal structures in the olfactory bulb, telencephalon, diencephalon, optic tectum, and cerebellum. This high resolution tilapia brain atlas is expected to become a very useful tool for neuroscientists using this fish model and will certainly expand their use in future studies regarding the central nervous system.

Whole-brain dynamic CT angiography and perfusion imaging

Energy Technology Data Exchange (ETDEWEB)

Orrison, W.W. [CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Department of Medical Education, University of Nevada School of Medicine, Reno, NV (United States); Snyder, K.V.; Hopkins, L.N. [Department of Neurosurgery, Millard Fillmore Gates Circle Hospital, Buffalo, NY (United States); Roach, C.J. [School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); Ringdahl, E.N. [Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV (United States); Nazir, R. [Shifa International Hospital, Islamabad (Pakistan); Hanson, E.H., E-mail: eric.hanson@amigenics.co [College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States)

2011-06-15

The availability of whole brain computed tomography (CT) perfusion has expanded the opportunities for analysing the haemodynamic parameters associated with varied neurological conditions. Examples demonstrating the clinical utility of whole-brain CT perfusion imaging in selected acute and chronic ischaemic arterial neurovascular conditions are presented. Whole-brain CT perfusion enables the detection and focused haemodynamic analyses of acute and chronic arterial conditions in the central nervous system without the limitation of partial anatomical coverage of the brain.

Three-dimensional imaging of absolute blood flow velocity and blood vessel position under low blood flow velocity based on Doppler signal information included in scattered light from red blood cells

Science.gov (United States)

Kyoden, Tomoaki; Akiguchi, Shunsuke; Tajiri, Tomoki; Andoh, Tsugunobu; Hachiga, Tadashi

2017-11-01

The development of a system for in vivo visualization of occluded distal blood vessels for diabetic patients is the main target of our research. We herein describe two-beam multipoint laser Doppler velocimetry (MLDV), which measures the instantaneous multipoint flow velocity and can be used to observe the blood flow velocity in peripheral blood vessels. By including a motorized stage to shift the measurement points horizontally and in the depth direction while measuring the velocity, the path of the blood vessel in the skin could be observed using blood flow velocity in three-dimensional space. The relationship of the signal power density between the blood vessel and the surrounding tissues was shown and helped us identify the position of the blood vessel. Two-beam MLDV can be used to simultaneously determine the absolute blood flow velocity distribution and identify the blood vessel position in skin.

Lysosomal storage diseases and the blood-brain barrier.

Science.gov (United States)

Begley, David J; Pontikis, Charles C; Scarpa, Maurizio

2008-01-01

The blood-brain barrier becomes a crucial issue in neuronopathic lysosomal storage diseases for three reasons. Firstly, the function of the blood-brain barrier may be compromised in many of the lysosomal storage diseases and this barrier dysfunction may contribute to the neuropathology seen in the diseases and accelerate cell death. Secondly, the substrate reduction therapies, which successfully reduce peripheral lysosomal storage, because of the blood-brain barrier may not have as free an access to brain cells as they do to peripheral cells. And thirdly, enzyme replacement therapy appears to have little access to the central nervous system as the mannose and mannose-6-phosphate receptors involved in their cellular uptake and transport to the lysosome do not appear to be expressed at the adult blood-brain barrier. This review will discuss in detail these issues and their context in the development of new therapeutic strategies.

Nonlinear dynamic response of whole pool multiple spent fuel racks subject to three-dimensional excitations

International Nuclear Information System (INIS)

Zhao, Y.; Wilson, P.R.; Stevenson, J.D.

1995-01-01

The seismic evaluation of submerged free standing spent fuel storage racks is more complicated than most other nuclear structural systems. When subjected to three dimensional (3-D) floor seismic excitations the dynamic responses of racks in a pool are hydro dynamically coupled with each other, with the fuel assemblies water in gaps. The motion behavior of the racks is significantly different from that observed using a 3D single rack mode. Few seismic analyses using 3-D whole pool multiple rack models are available in the literature. I this paper an analysis was performed for twelve racks using potential theory for the fluid-structure interaction, and using a 3-D whole pool multi-rack finite element model developed herein. The analysis includes the potential nonlinear dynamic behavior of the impact of fuel-rack, rack-rack and rack-pool wall, the tilting or uplift and the frictional sliding of rack supports, and the impact of the rack supports to the pool floor. (author). 12 refs., 7 figs., 1 tab

CFT description of three-dimensional Kerr-de Sitter spacetime

International Nuclear Information System (INIS)

Fjelstad, Jens; Hwang, Stephen; Maansson, Teresia

2002-01-01

We describe three-dimensional Kerr-de Sitter space using similar methods as recently applied to the BTZ black hole. A rigorous form of the classical connection between gravity in three dimensions and two-dimensional conformal field theory is employed, where the fundamental degrees of freedom are described in terms of two dependent SL(2,C) currents. In contrast to the BTZ case, however, quantization does not give the Bekenstein-Hawking entropy connected to the cosmological horizon of Kerr-de Sitter space

CFT description of three-dimensional Kerr-de Sitter spacetime

Energy Technology Data Exchange (ETDEWEB)

Fjelstad, Jens E-mail: jens.fjelstad@kau.se; Hwang, Stephen E-mail: stephen.hwang@kau.se; Maansson, Teresia E-mail: teresia@physto.se

2002-10-07

We describe three-dimensional Kerr-de Sitter space using similar methods as recently applied to the BTZ black hole. A rigorous form of the classical connection between gravity in three dimensions and two-dimensional conformal field theory is employed, where the fundamental degrees of freedom are described in terms of two dependent SL(2,C) currents. In contrast to the BTZ case, however, quantization does not give the Bekenstein-Hawking entropy connected to the cosmological horizon of Kerr-de Sitter space.

Measurement of regional cerebral blood flow using one-point arterial blood sampling and microsphere model with 123I-IMP. Correction of one-point arterial sampling count by whole brain count ratio

International Nuclear Information System (INIS)

Makino, Kenichi; Masuda, Yasuhiko; Gotoh, Satoshi

1998-01-01

The experimental subjects were 189 patients with cerebrovascular disorders. 123 I-IMP, 222 MBq, was administered by intravenous infusion. Continuous arterial blood sampling was carried out for 5 minutes, and arterial blood was also sampled once at 5 minutes after 123 I-IMP administration. Then the whole blood count of the one-point arterial sampling was compared with the octanol-extracted count of the continuous arterial sampling. A positive correlation was found between the two values. The ratio of the continuous sampling octanol-extracted count (OC) to the one-point sampling whole blood count (TC5) was compared with the whole brain count ratio (5:29 ratio, Cn) using 1-minute planar SPECT images, centering on 5 and 29 minutes after 123 I-IMP administration. Correlation was found between the two values. The following relationship was shown from the correlation equation. OC/TC5=0.390969 x Cn-0.08924. Based on this correlation equation, we calculated the theoretical continuous arterial sampling octanol-extracted count (COC). COC=TC5 x (0.390969 x Cn-0.08924). There was good correlation between the value calculated with this equation and the actually measured value. The coefficient improved to r=0.94 from the r=0.87 obtained before using the 5:29 ratio for correction. For 23 of these 189 cases, another one-point arterial sampling was carried out at 6, 7, 8, 9 and 10 minutes after the administration of 123 I-IMP. The correlation coefficient was also improved for these other point samplings when this correction method using the 5:29 ratio was applied. It was concluded that it is possible to obtain highly accurate input functions, i.e., calculated continuous arterial sampling octanol-extracted counts, using one-point arterial sampling whole blood counts by performing correction using the 5:29 ratio. (K.H.)

Types and three-dimensional distribution of neuronal ectopias in the brain of mice prenatally subjected to X-irradiation

Energy Technology Data Exchange (ETDEWEB)

Sun, Xue-Zhi; Takahashi, Sentaro; Kubota, Yoshihisa; Sato, Hiroshi [National Inst. of Radiological Sciences, Chiba (Japan); Cui, Chun; Fukui, Yoshihiro [Tokushima Univ. (Japan). School of Medicine; Inouye, Minoru [Shin Nippon Biomedical Lab., Ltd., Miyanoura, Kagoshima (Japan)

2002-03-01

The types and three-dimensional distribution of neocortical ectopias following prenatal exposure to X-irradiation were studied by a histological examination and computer reconstruction techniques. Pregnant ICR mice were subjected to X-irradiation at a dose of 1.5 Gy on embryonic day 13. The brains from 30-day-old mice were serially sectioned on the frontal plane at 15 {mu}m, stained with HE and observed with a microscope. The image data for the sections were input to a computer, and then reconstructed to three-dimensional brain structures using the Magellan 3.6 program. Sectional images were then drawn on a computer display at 240 {mu}m intervals, and the positions of the different types of neocortical ectopias were marked using color coding. Three types of neocortical ectopias were recognized in the irradiated brains. Neocortical Lay I ectopias were identified as small patches in the caudal occipital cortex, and were located more laterally in the neocortex in caudal sections than in the rostral sections. Periventricular ectopias were located more rostrally than Lay I ectopias, and were found from the most caudal extent of the presumed motor cortex to the most caudal extent of the lateral ventricle. Hippocampal ectopias appeared as continuous linear bands, and were frequently associated with the anterior parts of the periventricular ectopias. (author)

(2+1-dimensional regular black holes with nonlinear electrodynamics sources

Directory of Open Access Journals (Sweden)

Yun He

2017-11-01

Full Text Available On the basis of two requirements: the avoidance of the curvature singularity and the Maxwell theory as the weak field limit of the nonlinear electrodynamics, we find two restricted conditions on the metric function of (2+1-dimensional regular black hole in general relativity coupled with nonlinear electrodynamics sources. By the use of the two conditions, we obtain a general approach to construct (2+1-dimensional regular black holes. In this manner, we construct four (2+1-dimensional regular black holes as examples. We also study the thermodynamic properties of the regular black holes and verify the first law of black hole thermodynamics.

Two-dimensional black holes and non-commutative spaces

International Nuclear Information System (INIS)

Sadeghi, J.

2008-01-01

We study the effects of non-commutative spaces on two-dimensional black hole. The event horizon of two-dimensional black hole is obtained in non-commutative space up to second order of perturbative calculations. A lower limit for the non-commutativity parameter is also obtained. The observer in that limit in contrast to commutative case see two horizon

STANDARDIZATION OF GLYCOHEMOGLOBIN RESULTS AND REFERENCE VALUES IN WHOLE-BLOOD STUDIED IN 103 LABORATORIES USING 20 METHODS

NARCIS (Netherlands)

WEYKAMP, CW; PENDERS, TJ; MUSKIET, FAJ; VANDERSLIK, W

We investigated the effect of calibration with lyophilized calibrators on whole-blood glycohemoglobin (glyHb) results. One hundred three laboratories, using 20 different methods, determined glyHb in two lyophilized calibrators and two whole-blood samples. For whole-blood samples with low (5%) and

Volume Tracking: A new method for quantitative assessment and visualization of intracardiac blood flow from three-dimensional, time-resolved, three-component magnetic resonance velocity mapping

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Arheden Håkan

2011-04-01

Full Text Available Abstract Background Functional and morphological changes of the heart influence blood flow patterns. Therefore, flow patterns may carry diagnostic and prognostic information. Three-dimensional, time-resolved, three-directional phase contrast cardiovascular magnetic resonance (4D PC-CMR can image flow patterns with unique detail, and using new flow visualization methods may lead to new insights. The aim of this study is to present and validate a novel visualization method with a quantitative potential for blood flow from 4D PC-CMR, called Volume Tracking, and investigate if Volume Tracking complements particle tracing, the most common visualization method used today. Methods Eight healthy volunteers and one patient with a large apical left ventricular aneurysm underwent 4D PC-CMR flow imaging of the whole heart. Volume Tracking and particle tracing visualizations were compared visually side-by-side in a visualization software package. To validate Volume Tracking, the number of particle traces that agreed with the Volume Tracking visualizations was counted and expressed as a percentage of total released particles in mid-diastole and end-diastole respectively. Two independent observers described blood flow patterns in the left ventricle using Volume Tracking visualizations. Results Volume Tracking was feasible in all eight healthy volunteers and in the patient. Visually, Volume Tracking and particle tracing are complementary methods, showing different aspects of the flow. When validated against particle tracing, on average 90.5% and 87.8% of the particles agreed with the Volume Tracking surface in mid-diastole and end-diastole respectively. Inflow patterns in the left ventricle varied between the subjects, with excellent agreement between observers. The left ventricular inflow pattern in the patient differed from the healthy subjects. Conclusion Volume Tracking is a new visualization method for blood flow measured by 4D PC-CMR. Volume Tracking

Volume Tracking: A new method for quantitative assessment and visualization of intracardiac blood flow from three-dimensional, time-resolved, three-component magnetic resonance velocity mapping

International Nuclear Information System (INIS)

Töger, Johannes; Carlsson, Marcus; Söderlind, Gustaf; Arheden, Håkan; Heiberg, Einar

2011-01-01

Functional and morphological changes of the heart influence blood flow patterns. Therefore, flow patterns may carry diagnostic and prognostic information. Three-dimensional, time-resolved, three-directional phase contrast cardiovascular magnetic resonance (4D PC-CMR) can image flow patterns with unique detail, and using new flow visualization methods may lead to new insights. The aim of this study is to present and validate a novel visualization method with a quantitative potential for blood flow from 4D PC-CMR, called Volume Tracking, and investigate if Volume Tracking complements particle tracing, the most common visualization method used today. Eight healthy volunteers and one patient with a large apical left ventricular aneurysm underwent 4D PC-CMR flow imaging of the whole heart. Volume Tracking and particle tracing visualizations were compared visually side-by-side in a visualization software package. To validate Volume Tracking, the number of particle traces that agreed with the Volume Tracking visualizations was counted and expressed as a percentage of total released particles in mid-diastole and end-diastole respectively. Two independent observers described blood flow patterns in the left ventricle using Volume Tracking visualizations. Volume Tracking was feasible in all eight healthy volunteers and in the patient. Visually, Volume Tracking and particle tracing are complementary methods, showing different aspects of the flow. When validated against particle tracing, on average 90.5% and 87.8% of the particles agreed with the Volume Tracking surface in mid-diastole and end-diastole respectively. Inflow patterns in the left ventricle varied between the subjects, with excellent agreement between observers. The left ventricular inflow pattern in the patient differed from the healthy subjects. Volume Tracking is a new visualization method for blood flow measured by 4D PC-CMR. Volume Tracking complements and provides incremental information compared to particle

Whole-organ tissue engineering: decellularization and recellularization of three-dimensional matrix liver scaffolds.

Science.gov (United States)

Sabetkish, Shabnam; Kajbafzadeh, Abdol-Mohammad; Sabetkish, Nastaran; Khorramirouz, Reza; Akbarzadeh, Aram; Seyedian, Sanam Ladi; Pasalar, Parvin; Orangian, Saghar; Beigi, Reza Seyyed Hossein; Aryan, Zahra; Akbari, Hesam; Tavangar, Seyyed Mohammad

2015-04-01

To report the results of whole liver decellularization by two different methods. To present the results of grafting rat and sheep decellularized liver matrix (DLM) into the normal rat liver and compare natural cell seeding process in homo/xenograft of DLM. To compare the results of in vitro whole liver recellularization with rats' neonatal green fluorescent protein (GFP)-positive hepatic cells with outcomes of in vivo recellularization process. Whole liver of 8 rats and 4 sheep were resected and cannulated via the hepatic vein and perfused with sodium dodecyl sulfate (SDS) or Triton + SDS. Several examinations were performed to compare the efficacy of these two decellularization procedures. In vivo recellularization of sheep and rat DLMs was performed following transplantation of multiple pieces of both scaffolds in the subhepatic area of four rats. To compare the efficacy of different scaffolds in autologous cell seeding, biopsies of homograft and xenograft were assessed 8 weeks postoperatively. Whole DLMs of 4 rats were also recellularized in vitro by perfusion of rat's fetal GFP-positive hepatic cells with pulsatile bioreactor. Histological evaluation and enzymatic assay were performed for both in vivo and in vitro recellularized samples. The results of this study demonstrated that the triton method was a promising decellularization approach for preserving the three-dimensional structure of liver. In vitro recellularized DLMs were more similar to natural ones compared with in vivo recellularized livers. However, homografts showed better characteristics with more organized structure compared with xenografts. In vitro recellularization of liver scaffolds with autologous cells represents an attractive prospective for regeneration of liver as one of the most compound organs. In vivo cell seeding on the scaffold of the same species may have more satisfactory outcomes when compared with the results of xenotransplantation. This study theoretically may pave the road for

A Lifshitz black hole in four dimensional R2 gravity

International Nuclear Information System (INIS)

Cai Ronggen; Liu Yan; Sun Yawen

2009-01-01

We consider a higher derivative gravity theory in four dimensions with a negative cosmological constant and show that vacuum solutions of both Lifshitz type and Schroedinger type with arbitrary dynamical exponent z exist in this system. Then we find an analytic black hole solution which asymptotes to the vacuum Lifshitz solution with z = 3/2 at a specific value of the coupling constant. We analyze the thermodynamic behavior of this black hole and find that the black hole has zero entropy while non-zero temperature, which is very similar to the case of BTZ black holes in new massive gravity at a specific coupling. In addition, we find that the three dimensional Lifshitz black hole recently found by E. Ayon-Beato et al. has a negative entropy and mass when the Newton constant is taken to be positive.

Influence of turmeric rhizome and black pepper on blood ...

African Journals Online (AJOL)

2012-04-26

) and black pepper. (BP) on blood components and performance of male broiler chickens. A 2 × 3 factorial arrangement with two levels of TRP (0 and 0.5 g/kg) and three levels of BP (0, 0.5 and 1 g/kg) were used to provide six.

Assessment by three-dimensional power Doppler ultrasound of cerebral blood flow perfusion in fetuses with congenital heart disease.

Science.gov (United States)

Zeng, S; Zhou, J; Peng, Q; Tian, L; Xu, G; Zhao, Y; Wang, T; Zhou, Q

2015-06-01

To use three-dimensional (3D) power Doppler ultrasound to investigate cerebral blood flow perfusion in fetuses with congenital heart disease (CHD). The vascularization index (VI), flow index (FI) and vascularization flow index (VFI) in the total intracranial volume and the main arterial territories (middle cerebral artery (MCA), anterior cerebral artery (ACA) and posterior cerebral artery (PCA)) were evaluated prospectively and compared in 112 fetuses with CHD and 112 normal fetuses using 3D power Doppler. Correlations between the 3D power Doppler indices and neurodevelopment scores at 12 months of age were assessed in a subset of the CHD group, and values were compared with those of controls. Compared with the controls, the VI, FI and VFI of the total intracranial volume and the three main arteries were significantly higher in fetuses with hypoplastic left heart syndrome and left-sided obstructive lesions (P power Doppler values in the ACA territory were significantly higher in fetuses with transposition of the great arteries (P power Doppler ultrasound might help to identify cases of brain vasodilatation earlier and inform parental counseling. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Aspects of noncommutative (1+1)-dimensional black holes

International Nuclear Information System (INIS)

Mureika, Jonas R.; Nicolini, Piero

2011-01-01

We present a comprehensive analysis of the spacetime structure and thermodynamics of (1+1)-dimensional black holes in a noncommutative framework. It is shown that a wider variety of solutions are possible than the commutative case considered previously in the literature. As expected, the introduction of a minimal length √(θ) cures singularity pathologies that plague the standard two-dimensional general relativistic case, where the latter solution is recovered at large length scales. Depending on the choice of input parameters (black hole mass M, cosmological constant Λ, etc.), black hole solutions with zero, up to six, horizons are possible. The associated thermodynamics allows for the either complete evaporation, or the production of black hole remnants.

Can Whole-Grain Foods Lower Blood Pressure?

Science.gov (United States)

... eating more whole-grain foods help lower my blood pressure? Answers from Sheldon G. Sheps, M.D. It might. Eating ... might help reduce your chance of developing high blood pressure (hypertension). Whole grains are grains that include the ...

Scale-dependent three-dimensional charged black holes in linear and non-linear electrodynamics

Energy Technology Data Exchange (ETDEWEB)

Rincon, Angel; Koch, Benjamin [Pontificia Universidad Catolica de Chile, Instituto de Fisica, Santiago (Chile); Contreras, Ernesto; Bargueno, Pedro; Hernandez-Arboleda, Alejandro [Universidad de los Andes, Departamento de Fisica, Bogota, Distrito Capital (Colombia); Panotopoulos, Grigorios [Universidade de Lisboa, CENTRA, Instituto Superior Tecnico, Lisboa (Portugal)

2017-07-15

In the present work we study the scale dependence at the level of the effective action of charged black holes in Einstein-Maxwell as well as in Einstein-power-Maxwell theories in (2 + 1)-dimensional spacetimes without a cosmological constant. We allow for scale dependence of the gravitational and electromagnetic couplings, and we solve the corresponding generalized field equations imposing the null energy condition. Certain properties, such as horizon structure and thermodynamics, are discussed in detail. (orig.)

A femoral arteriovenous shunt facilitates arterial whole blood sampling in animals

International Nuclear Information System (INIS)

Weber, Bruno; Burger, Cyrill; Buck, Alfred; Biro, Peter

2002-01-01

In this study we evaluated on-line continuous blood sampling in a femoral arteriovenous (a-v) shunt for use in quantitative tracer studies using gamma-emitting radionuclides in animals. The shunt consisted of 40 cm polyethylene tubing (PE-50) guided through a coincidence probe. Two three-way valves allowed blood pressure measurements and tracer injection. Blood flow in the shunt and the impulse response function (IRF) were assessed using heparinized human blood mixed with fluorine-18 fluorodeoxyglucose (FDG). In vivo experiments were performed in eight male rats (300-350 g) anaesthetized with halothane. In three rats, manual blood sampling was performed in parallel with on-line sampling. In another five animals, the arterial whole blood activity was recorded on-line for 40 min. For the experiments 150-180 MBq FDG was injected over 35 s. Blood flow in the shunt was 23.6, 29.2 and 42.8 ml/h at 100, 120 and 160 mmHg, respectively. The IRF was characterized by minimal dispersion (1-2 s FWHM). Deconvolution of the measured arterial input curves with the IRF changed the measured curve only minimally. Whole blood radioactivity concentration derived from manual and on-line sampling were in excellent agreement. The curves derived from on-line sampling were of high statistical quality. In conclusion, a femoral a-v shunt allows multiple manipulations such as measurement of the arterial whole blood activity, continuous blood pressure monitoring, injection of the tracer and collection of blood samples if necessary. It is not associated with blood loss if the collection of blood samples is not required. It is more convenient to use than manual sampling, the peak of the input curve is never missed and the input curves are of high statistical quality. (orig.)

Concurrent whole brain radiotherapy and bortezomib for brain metastasis

International Nuclear Information System (INIS)

Lao, Christopher D; Hamstra, Daniel; Lawrence, Theodore; Hayman, James; Redman, Bruce G; Friedman, Judah; Tsien, Christina I; Normolle, Daniel P; Chapman, Christopher; Cao, Yue; Lee, Oliver; Schipper, Matt; Van Poznak, Catherine

2013-01-01

Survival of patients with brain metastasis particularly from historically more radio-resistant malignancies remains dismal. A phase I study of concurrent bortezomib and whole brain radiotherapy was conducted to determine the tolerance and safety of this approach in patients with previously untreated brain metastasis. A phase I dose escalation study evaluated the safety of bortezomib (0.9, 1.1, 1.3, 1.5, and 1.7 mg/m 2 ) given on days 1, 4, 8 and 11 of whole brain radiotherapy. Patients with confirmed brain metastasis were recruited for participation. The primary endpoint was the dose-limiting toxicity, defined as any ≥ grade 3 non-hematologic toxicity or grade ≥ 4 hematologic toxicity from the start of treatment to one month post irradiation. Time-to-Event Continual Reassessment Method (TITE-CRM) was used to determine dose escalation. A companion study of brain diffusion tensor imaging MRI was conducted on a subset of patients to assess changes in the brain that might predict delayed cognitive effects. Twenty-four patients were recruited and completed the planned therapy. Patients with melanoma accounted for 83% of all participants. The bortezomib dose was escalated as planned to the highest dose of 1.7 mg/m 2 /dose. No grade 4/5 toxicities related to treatment were observed. Two patients had grade 3 dose-limiting toxicities (hyponatremia and encephalopathy). A partial or minor response was observed in 38% of patients. Bortezomib showed greater demyelination in hippocampus-associated white matter structures on MRI one month after radiotherapy compared to patients not treated with bortezomib (increase in radial diffusivity +16.8% versus 4.8%; p = 0.0023). Concurrent bortezomib and whole brain irradiation for brain metastasis is well tolerated at one month follow-up, but MRI changes that have been shown to predict delayed cognitive function can be detected within one month of treatment

Charged rotating black holes in four-dimensional gauged and ungauged supergravities

International Nuclear Information System (INIS)

Chong, Z.-W.; Cvetic, M.; Lue, H.; Pope, C.N.

2005-01-01

We study four-dimensional non-extremal charged rotating black holes in ungauged and gauged supergravity. In the ungauged case, we obtain rotating black holes with four independent charges, as solutions of N=2 supergravity coupled to three Abelian vector multiplets. This is done by reducing the theory along the time direction to three dimensions, where it has an O(4,4) global symmetry. Applied to the reduction of the uncharged Kerr metric, O(1,1) 4 is a subject of O(4,4) transformations generate new solutions that correspond, after lifting back to four dimensions, to the introduction of four independent electromagnetic charges. In the case where these charges are set pairwise equal, we then generalise the four-dimensional rotating black holes to solutions of gauged N=4 supergravity, with mass, angular momentum and two independent electromagnetic charges. The dilaton and axion fields are non-constant. We also find generalisations of the gauged and ungauged solutions to include the NUT parameter, and for the ungauged solutions, the acceleration parameter too. The solutions in gauged supergravity provide new gravitational backgrounds for a further study of the AdS 4 /CFT 3 correspondence at non-zero temperature

Three-dimensional reconstruction and visualization system for medical images

International Nuclear Information System (INIS)

Preston, D.F.; Batnitzky, S.; Kyo Rak Lee; Cook, P.N.; Cook, L.T.; Dwyer, S.J.

1982-01-01

A three-dimensional reconstruction and visualization system could be of significant advantage in medical application such as neurosurgery and radiation treatment planning. The reconstructed anatomic structures from CT head scans could be used in a head stereotactic system to help plan the surgical procedure and the radiation treatment for a brain lesion. Also, the use of three-dimensional reconstruction algorithm provides for quantitative measures such as volume and surface area estimation of the anatomic features. This aspect of the three-dimensional reconstruction system may be used to monitor the progress or staging of a disease and the effects of patient treatment. Two cases are presented to illustrate the three-dimensional surface reconstruction and visualization system

The spectrum of the two-dimensional black hole or does the two-dimensional black hole have tachyonic or W-hair?

International Nuclear Information System (INIS)

Marcus, N.; Oz, Y.

1993-01-01

We solve the equations of motion of the tachyon and the discrete states in the background of Witten's semiclassical black hole and in the exact two-dimensional dilaton-graviton background of Dijkgraaf et al. We find the exact solutions for weak fields, leading to conclusions in disagreement with previous studies of tachyons in the black hole. Demanding that a state in the black hole be well behaved at the horizon implies that it must tend asymptotically to a combination of a Seiberg and an anti-Seiberg c=1 state. For such a state to be well behaved asymptotically, it must satisfy the condition that neither its Seiberg nor its anti-Seiberg Liouville momentum is positive. Thus, although the free-field BRST cohomologies of the underlying SL(2, R) theory is the same as that of a c=1 theory, the black-hole spectrum is drastically truncated: There are no W ∞ states, and only tachyons with x-momenta vertical stroke p tach ≤m tach vertical stroke are allowed. In the Minkowski case only the static tachyon is allowed. The black hole is stable to the back reaction of these remaining tachyons, so they are good perturbations of the black hole, or 'hair'. However, this leaves only three tachyonic hairs in the black hole and seven in the exact solution. Such sparse hair is clearly irrelevant to the maintenance of coherence during black-hole evaporation. (orig.)

Rapid transport of CCL11 across the blood-brain barrier: regional variation and importance of blood cells.

Science.gov (United States)

Erickson, Michelle A; Morofuji, Yoichi; Owen, Joshua B; Banks, William A

2014-06-01

Increased blood levels of the eotaxin chemokine C-C motif ligand 11 (CCL11) in aging were recently shown to negatively regulate adult hippocampal neurogenesis. How circulating CCL11 could affect the central nervous system (CNS) is not clear, but one possibility is that it can cross the blood-brain barrier (BBB). Here, we show that CCL11 undergoes bidirectional transport across the BBB. Transport of CCL11 from blood into whole brain (influx) showed biphasic kinetics, with a slow phase preceding a rapid phase of uptake. We found that the slow phase was explained by binding of CCL11 to cellular components in blood, whereas the rapid uptake phase was mediated by direct interactions with the BBB. CCL11, even at high doses, did not cause BBB disruption. All brain regions except striatum showed a delayed rapid-uptake phase. Striatum had only an early rapid-uptake phase, which was the fastest of any brain region. We also observed a slow but saturable transport system for CCL11 from brain to blood. C-C motif ligand 3 (CCR3), an important receptor for CCL11, did not facilitate CCL11 transport across the BBB, although high concentrations of a CCR3 inhibitor increased brain uptake without causing BBB disruption. Our results indicate that CCL11 in the circulation can access many regions of the brain outside of the neurogenic niche via transport across the BBB. This suggests that blood-borne CCL11 may have important physiologic functions in the CNS and implicates the BBB as an important regulator of physiologic versus pathologic effects of this chemokine.

Influence of turmeric rhizome and black pepper on blood ...

African Journals Online (AJOL)

) and black pepper (BP) on blood components and performance of male broiler chickens. A 2 × 3 factorial arrangement with two levels of TRP (0 and 0.5 g/kg) and three levels of BP (0, 0.5 and 1 g/kg) were used to provide six dietary treatments ...

Early changes of cortical blood flow, brain temperature and electrical activity after whole-body irradiation of the monkey (Macaca fascicularis) (dose range: 3-20 Gy)

International Nuclear Information System (INIS)

Court, L.; Gourmelon, P.; Mestries, J.C.

1987-02-01

A polyparametric investigation was carried out on 31 monkeys chronically wearing bioinstrumentation allowing to get and process simultaneously local brain blood flow, cerebral temperature, and energies in various frequency bands of the brain electrical activity. This method, which supplied data during several consecutive days, made it possible to study both the biological rhythms at the level of the various parameters, and their fast variations. The effects of whole-body gamma or neutron-gamma irradiation were studied in the 3-20 Gy dose range. Immediate changes after exposure demonstrated different radiosensitivities at the level of the rhythms of the various parameters, and/or their recovery, as well as dose-effect relationships [fr

Intracranial arterial wall enhancement using gadolinium-enhanced 3D black-blood T1-weighted imaging

Energy Technology Data Exchange (ETDEWEB)

Takano, Koichi, E-mail: k-takano@fukuoka-u.ac.jp; Hida, Kosuke; Kuwabara, Yasuo; Yoshimitsu, Kengo

2017-01-15

Purpose: We investigated the enhancement of the intracranial arterial walls with gadolinium-enhanced, black-blood three-dimensional T1-weighted imaging (Gd-3DBB) by using an improved motion-sensitized driven-equilibrium (iMSDE)—prepared volumetric isotropic turbo spin-echo acquisition (VISTA). Methods: A total of 115 patients underwent FLAIR, 3D-TOF-MRA and Gd-3DBB with a 1.5-T scanner. The degree and distribution of the arterial wall enhancement on Gd-3DBB was assessed. The association of the degree of wall enhancement with brain infarction/ischemic lesions on FLAIR, luminal changes on 3D-TOF-MRA, and cardiovascular risk factors (CVRFs) was investigated by univariate and multiple logistic regression analyses. Results: Strong enhancement of the arterial walls was observed in 77 vertebral arteries (33.5%), 4 basilar arteries (3.5%), 31 supraclinoid internal carotid arteries (ICAs) (13.5%) and 8 middle cerebral arteries (3.5%). In addition, 221 intrapetrous ICAs (96.1%) showed strong enhancement. After adjusting for confounding factors, multivariate analyses showed that the patient age was independently associated with the strong wall enhancement of the arteries for both the posterior (OR, 1.088; 95% CI, 1.034–1.146) and the anterior circulation (OR, 1.098, 95% CI 1.029–1.172). In addition, the presence of the supratentorial brain infarctions was independently associated with the strong wall enhancement in the anterior circulation excluding the intrapetrous ICAs (OR, 4.097; 95% CI, 1.483–11.319). Conclusions: Although the arterial wall enhancement on the Gd-3DBB probably reflects normal aging, the enhancement in the anterior circulation might be related to brain infarctions. On the other hand, the intrapetrous ICA enhancement is considered a nonspecific finding and should not be mistaken for arterial pathologies such as atherosclerosis or arteritis.

Intracranial arterial wall enhancement using gadolinium-enhanced 3D black-blood T1-weighted imaging

International Nuclear Information System (INIS)

Takano, Koichi; Hida, Kosuke; Kuwabara, Yasuo; Yoshimitsu, Kengo

2017-01-01

Purpose: We investigated the enhancement of the intracranial arterial walls with gadolinium-enhanced, black-blood three-dimensional T1-weighted imaging (Gd-3DBB) by using an improved motion-sensitized driven-equilibrium (iMSDE)—prepared volumetric isotropic turbo spin-echo acquisition (VISTA). Methods: A total of 115 patients underwent FLAIR, 3D-TOF-MRA and Gd-3DBB with a 1.5-T scanner. The degree and distribution of the arterial wall enhancement on Gd-3DBB was assessed. The association of the degree of wall enhancement with brain infarction/ischemic lesions on FLAIR, luminal changes on 3D-TOF-MRA, and cardiovascular risk factors (CVRFs) was investigated by univariate and multiple logistic regression analyses. Results: Strong enhancement of the arterial walls was observed in 77 vertebral arteries (33.5%), 4 basilar arteries (3.5%), 31 supraclinoid internal carotid arteries (ICAs) (13.5%) and 8 middle cerebral arteries (3.5%). In addition, 221 intrapetrous ICAs (96.1%) showed strong enhancement. After adjusting for confounding factors, multivariate analyses showed that the patient age was independently associated with the strong wall enhancement of the arteries for both the posterior (OR, 1.088; 95% CI, 1.034–1.146) and the anterior circulation (OR, 1.098, 95% CI 1.029–1.172). In addition, the presence of the supratentorial brain infarctions was independently associated with the strong wall enhancement in the anterior circulation excluding the intrapetrous ICAs (OR, 4.097; 95% CI, 1.483–11.319). Conclusions: Although the arterial wall enhancement on the Gd-3DBB probably reflects normal aging, the enhancement in the anterior circulation might be related to brain infarctions. On the other hand, the intrapetrous ICA enhancement is considered a nonspecific finding and should not be mistaken for arterial pathologies such as atherosclerosis or arteritis.

Whole brain and brain regional coexpression network interactions associated with predisposition to alcohol consumption.

Directory of Open Access Journals (Sweden)

Lauren A Vanderlinden

Full Text Available To identify brain transcriptional networks that may predispose an animal to consume alcohol, we used weighted gene coexpression network analysis (WGCNA. Candidate coexpression modules are those with an eigengene expression level that correlates significantly with the level of alcohol consumption across a panel of BXD recombinant inbred mouse strains, and that share a genomic region that regulates the module transcript expression levels (mQTL with a genomic region that regulates alcohol consumption (bQTL. To address a controversy regarding utility of gene expression profiles from whole brain, vs specific brain regions, as indicators of the relationship of gene expression to phenotype, we compared candidate coexpression modules from whole brain gene expression data (gathered with Affymetrix 430 v2 arrays in the Colorado laboratories and from gene expression data from 6 brain regions (nucleus accumbens (NA; prefrontal cortex (PFC; ventral tegmental area (VTA; striatum (ST; hippocampus (HP; cerebellum (CB available from GeneNetwork. The candidate modules were used to construct candidate eigengene networks across brain regions, resulting in three "meta-modules", composed of candidate modules from two or more brain regions (NA, PFC, ST, VTA and whole brain. To mitigate the potential influence of chromosomal location of transcripts and cis-eQTLs in linkage disequilibrium, we calculated a semi-partial correlation of the transcripts in the meta-modules with alcohol consumption conditional on the transcripts' cis-eQTLs. The function of transcripts that retained the correlation with the phenotype after correction for the strong genetic influence, implicates processes of protein metabolism in the ER and Golgi as influencing susceptibility to variation in alcohol consumption. Integration of these data with human GWAS provides further information on the function of polymorphisms associated with alcohol-related traits.

Novel MRI methodology to detect human whole-brain connectivity changes after ingestion of fructose or glucose

Science.gov (United States)

Tsao, Sinchai; Wilkins, Bryce; Page, Kathleen A.; Singh, Manbir

2012-03-01

A novel MRI protocol has been developed to investigate the differential effects of glucose or fructose consumption on whole-brain functional brain connectivity. A previous study has reported a decrease in the fMRI blood oxygen level dependent (BOLD) signal of the hypothalamus following glucose ingestion, but due to technical limitations, was restricted to a single slice covering the hypothalamus, and thus unable to detect whole-brain connectivity. In another previous study, a protocol was devised to acquire whole-brain fMRI data following food intake, but only after restricting image acquisition to an MR sampling or repetition time (TR) of 20s, making the protocol unsuitable to detect functional connectivity above 0.025Hz. We have successfully implemented a continuous 36-min, 40 contiguous slices, whole-brain BOLD acquisition protocol on a 3T scanner with TR=4.5s to ensure detection of up to 0.1Hz frequencies for whole-brain functional connectivity analysis. Human data were acquired first with ingestion of water only, followed by a glucose or fructose drink within the scanner, without interrupting the scanning. Whole-brain connectivity was analyzed using standard correlation methodology in the 0.01-0.1 Hz range. The correlation coefficient differences between fructose and glucose ingestion among targeted regions were converted to t-scores using the water-only correlation coefficients as a null condition. Results show a dramatic increase in the hypothalamic connectivity to the hippocampus, amygdala, insula, caudate and the nucleus accumben for fructose over glucose. As these regions are known to be key components of the feeding and reward brain circuits, these results suggest a preference for fructose ingestion.

Whole-blood viscosity and the insulin-resistance syndrome.

Science.gov (United States)

Høieggen, A; Fossum, E; Moan, A; Enger, E; Kjeldsen, S E

1998-02-01

In a previous study we found that elevated blood viscosity was linked to the insulin resistance syndrome, and we proposed that high blood viscosity may increase insulin resistance. That study was based on calculated viscosity. To determine whether directly measured whole-blood viscosity was related to the insulin-resistance syndrome in the same way as calculated viscosity had been found to be. Healthy young men were examined with the hyperinsulinemic isoglycemic glucose clamp technique, and we related insulin sensitivity (glucose disposal rate) to other metabolic parameters and to blood viscosity. We established a technique for direct measurement of whole-blood viscosity. There were statistically significant negative correlations between glucose disposal rate and whole-blood viscosity at low and high shear rates (r = -0.41, P = 0.007 for both, n = 42). Whole-blood viscosity was correlated positively (n = 15) to serum triglyceride (r = 0.54, P = 0.04) and total cholesterol (r = 0.52, P = 0.05), and negatively with high-density lipoprotein cholesterol (r = -0.53, P = 0.04) concentrations. Insulin sensitivity index was correlated positively to high-density lipoprotein cholesterol (r = 0.54, P = 0.04) and negatively to serum triglyceride (r = -0.69, P = 0.005) and to total cholesterol (r = -0.81, P = 0.0003) concentrations. The present results demonstrate for the first time that there is a negative relationship between directly measured whole-blood viscosity and insulin sensitivity as a part of the insulin-resistance syndrome. Whole-blood viscosity contributes to the total peripheral resistance, and these results support the hypothesis that insulin resistance has a hemodynamic basis.

Cord blood buffy coat DNA methylation is comparable to whole cord blood methylation.

Science.gov (United States)

Dou, John; Schmidt, Rebecca J; Benke, Kelly S; Newschaffer, Craig; Hertz-Picciotto, Irva; Croen, Lisa A; Iosif, Ana-Maria; LaSalle, Janine M; Fallin, M Daniele; Bakulski, Kelly M

2018-01-01

Cord blood DNA methylation is associated with numerous health outcomes and environmental exposures. Whole cord blood DNA reflects all nucleated blood cell types, while centrifuging whole blood separates red blood cells, generating a white blood cell buffy coat. Both sample types are used in DNA methylation studies. Cell types have unique methylation patterns and processing can impact cell distributions, which may influence comparability. We evaluated differences in cell composition and DNA methylation between cord blood buffy coat and whole cord blood samples. Cord blood DNA methylation was measured with the Infinium EPIC BeadChip (Illumina) in eight individuals, each contributing buffy coat and whole blood samples. We analyzed principal components (PC) of methylation, performed hierarchical clustering, and computed correlations of mean-centered methylation between pairs. We conducted moderated t-tests on single sites and estimated cell composition. DNA methylation PCs were associated with individual (P PC1 = 1.4 × 10 -9 ; P PC2 = 2.9 × 10 -5 ; P PC3 = 3.8 × 10 -5 ; P PC4 = 4.2 × 10 -6 ; P PC5 = 9.9 × 10 -13 , P PC6 = 1.3 × 10 -11 ) and not with sample type (P PC1-6 >0.7). Samples hierarchically clustered by individual. Pearson correlations of mean-centered methylation between paired samples ranged from r = 0.66 to r = 0.87. No individual site significantly differed between buffy coat and whole cord blood when adjusting for multiple comparisons (five sites had unadjusted Pcoat and whole cord blood are much lower than inter-individual variation, demonstrating that both sample preparation types can be analytically combined and compared.

Birkhoff's Theorem for Three-Dimensional AdS Gravity

OpenAIRE

Ayón-Beato, Eloy; Martínez, Cristián; Zanelli, Jorge

2004-01-01

All three-dimensional matter-free spacetimes with negative cosmological constant, compatible with cyclic symmetry are identified. The only cyclic solutions are the 2+1 (BTZ) black hole with SO(2) x R isometry, and the self-dual Coussaert-Henneaux spacetimes, with isometry groups SO(2) x SO(2,1) or SO(2) x SO(2).

An easy to produce and economical three-dimensional brain phantom for stereotactic computed tomographic-guided brain biopsy training in the dog.

Science.gov (United States)

Sidhu, Deepinder S; Ruth, Jeffrey D; Lambert, Gregory; Rossmeisl, John H

2017-07-01

To develop and validate a three-dimensional (3D) brain phantom that can be incorporated into existing stereotactic headframes to simulate stereotactic brain biopsy (SBB) and train veterinary surgeons. Experimental study. Canine brain phantoms were fabricated from osteological skull specimens, agarose brain parenchyma, and cheddar and mozzarella cheese molds (simulating meningiomas and gliomas). The neuroradiologic and viscoelastic properties of phantoms were quantified with computed tomography (CT) and oscillatory compression tests, respectively. Phantoms were validated by experienced and novice operators performing SBB on phantoms containing randomly placed, focal targets. Target yield and needle placement error (NPE) were compared between operators. Phantoms were produced in brain parenchyma, and contrast-enhancing tumors of meningeal and glial origin, respectively. The complex moduli of the agarose and cheeses were comparable to the viscoelastic properties of in vivo brain tissues and brain tumors. The overall diagnostic yield of SBB was 88%. Although NPE did not differ between novice (median 3.68 mm; range, 1.46-14.54 mm) and experienced surgeons (median 1.17 mm, range, 0.78-1.58 mm), our results support the relevance of the learning curve associated with the SBB procedure. This 3D phantom replicates anatomical, CT, and tactile features of brain tissues and tumors and can be used to develop the technical skills required to perform SBB. © 2017 The American College of Veterinary Surgeons.

Postmortem magnetic resonance images of the injured brain: effective evidence in the courtroom.

Science.gov (United States)

Harris, L S

1991-09-01

Magnetic resonance images (MRI) of the whole, formalin-fixed brain produce details of pathologic changes deep within brain substance not apparent on external examination. Photographs of these radiographic images present pathologic features in a black-and-white, 2-dimensional format which has proven particularly effective in court before judge and jury. This pathologist has noted acceptance of such photographs in explaining to jurors the details of his testimony in selected cases where brain trauma resulted in a wrongful death. Penetrating missile wounds and blunt impact injuries are particularly well documented by this method.

Bayesian Modelling of Functional Whole Brain Connectivity

DEFF Research Database (Denmark)

Røge, Rasmus

the prevalent strategy of standardizing of fMRI time series and model data using directional statistics or we model the variability in the signal across the brain and across multiple subjects. In either case, we use Bayesian nonparametric modeling to automatically learn from the fMRI data the number......This thesis deals with parcellation of whole-brain functional magnetic resonance imaging (fMRI) using Bayesian inference with mixture models tailored to the fMRI data. In the three included papers and manuscripts, we analyze two different approaches to modeling fMRI signal; either we accept...... of funcional units, i.e. parcels. We benchmark the proposed mixture models against state of the art methods of brain parcellation, both probabilistic and non-probabilistic. The time series of each voxel are most often standardized using z-scoring which projects the time series data onto a hypersphere...

On the effect of long-term electrical stimulation on three-dimensional cell cultures: Hen embryo brain spheroids

OpenAIRE

Uroukov, Ivan S; Bull, Larry

2008-01-01

A comprehensive dataset of multielectrode array recordings was collected from three-dimensional hen embryo brain cell cultures, termed spheroids, under long-term electrical stimulation. The aim is to understand the ongoing changes in the spiking activity under electrical stimulation within the lifetime of 14–72DIV of the neuronal networks contained therein. The spiking dynamics were analyzed and behavioral characteristics derived. Some effects on spiking patterns and exhaustion were followed ...

Development of model plans in three dimensional conformal radiotherapy for brain tumors

International Nuclear Information System (INIS)

Pyo, Hongryull; Kim, Gwieon; Keum, Kichang; Chang, Sekyung; Suh, Changok; Lee, Sanghoon

2002-01-01

Three dimensional conformal radiotherapy planning is being used widely for the treatment of patients with brain tumor. However, it takes much time to develop an optimal treatment plan, therefore, it is difficult to apply this technique to all patients. To increase the efficiency of this technique, we need to develop standard radiotherapy plans for each site of the brain. Therefore we developed several 3 dimensional conformal radiotherapy plans (3D plans) for tumors at each site of brain, compared them with each other, and with 2 dimensional radiotherapy plans. Finally model plans for each site of the brain were decided. Imaginary tumors, with sizes commonly observed in the clinic, were designed for each site of the brain and drawn on CT images. The planning target volumes (PTVs) were as follows; temporal tumor-5.7 x 8.2 x 7.6 cm, suprasellar tumor-3 x 4 x 4.1 cm, thalamic tumor-3.1 x 5.9 x 3.7 cm, frontoparietal tumor-5.5 x 7 x 5.5 cm, and occipitoparietal tumor-5 x 5.5 x 5 cm. Plans using parallel opposed 2-portals and/or 3 portals including fronto-vertex and 2 lateral fields were developed manually as the conventional 2D plans, and 3D noncoplanar conformal plans were developed using beam's eye view and the automatic block drawing tool. Total tumor dose was 54 Gy for a suprasellar tumor, 59.4 Gy and 72 Gy for the other tumors. All dose plans (including 2D plans) were calculated using 3D plan software. Developed plans were compared with each other using dose-volume histograms (DVH), normal tissue complication probabilities (NTCP) and variable dose statistic values (minimum, maximum and mean dose, D5, V83, V85 and V95). Finally a best radiotherapy plan for each site of brain was selected. 1) Temporal tumor; NTCPs and DVHs of the normal tissue of all 3D plans were superior to 2D plans and this trend was more definite when total dose was escalated to 72 Gy (NTCPs of normal brain 2D plans: 27%, 8% → 3D plans: 1%, 1%). Various dose statistic values did not show any

Advanced CUBIC protocols for whole-brain and whole-body clearing and imaging.

Science.gov (United States)

Susaki, Etsuo A; Tainaka, Kazuki; Perrin, Dimitri; Yukinaga, Hiroko; Kuno, Akihiro; Ueda, Hiroki R

2015-11-01

Here we describe a protocol for advanced CUBIC (Clear, Unobstructed Brain/Body Imaging Cocktails and Computational analysis). The CUBIC protocol enables simple and efficient organ clearing, rapid imaging by light-sheet microscopy and quantitative imaging analysis of multiple samples. The organ or body is cleared by immersion for 1-14 d, with the exact time required dependent on the sample type and the experimental purposes. A single imaging set can be completed in 30-60 min. Image processing and analysis can take whole-brain neural activities at single-cell resolution using Arc-dVenus transgenic (Tg) mice. CUBIC informatics calculated the Venus signal subtraction, comparing different brains at a whole-organ scale. These protocols provide a platform for organism-level systems biology by comprehensively detecting cells in a whole organ or body.

A gene co-expression network in whole blood of schizophrenia patients is independent of antipsychotic-use and enriched for brain-expressed genes.

Directory of Open Access Journals (Sweden)

Simone de Jong

Full Text Available Despite large-scale genome-wide association studies (GWAS, the underlying genes for schizophrenia are largely unknown. Additional approaches are therefore required to identify the genetic background of this disorder. Here we report findings from a large gene expression study in peripheral blood of schizophrenia patients and controls. We applied a systems biology approach to genome-wide expression data from whole blood of 92 medicated and 29 antipsychotic-free schizophrenia patients and 118 healthy controls. We show that gene expression profiling in whole blood can identify twelve large gene co-expression modules associated with schizophrenia. Several of these disease related modules are likely to reflect expression changes due to antipsychotic medication. However, two of the disease modules could be replicated in an independent second data set involving antipsychotic-free patients and controls. One of these robustly defined disease modules is significantly enriched with brain-expressed genes and with genetic variants that were implicated in a GWAS study, which could imply a causal role in schizophrenia etiology. The most highly connected intramodular hub gene in this module (ABCF1, is located in, and regulated by the major histocompatibility (MHC complex, which is intriguing in light of the fact that common allelic variants from the MHC region have been implicated in schizophrenia. This suggests that the MHC increases schizophrenia susceptibility via altered gene expression of regulatory genes in this network.

Birkhoff's theorem for three-dimensional AdS gravity

International Nuclear Information System (INIS)

Ayon-Beato, Eloy; Martinez, Cristian; Zanelli, Jorge

2004-01-01

All three-dimensional matter-free space-times with negative cosmological constant, compatible with cyclic symmetry, are identified. The only cyclic solutions are the 2+1 (BTZ) black hole with SO(2)xR isometry, and the self-dual Coussaert-Henneaux space-times, with isometry groups SO(2)xSO(2,1) or SO(2)xSO(2)

Intact blood-brain barrier during spontaneous attacks of migraine without aura

DEFF Research Database (Denmark)

Amin, F M; Hougaard, A; Cramer, S P

2017-01-01

BACKGROUND AND PURPOSE: The integrity of the blood-brain barrier (BBB) has been questioned in migraine, but BBB permeability has never been investigated during spontaneous migraine attacks. In the present study, BBB permeability during spontaneous attacks of migraine without aura was investigated......, brain stem, posterior pons and whole brain. The paired samples t test was used to compare Ki (permeability) values between the attack and headache-free days. RESULTS: Nineteen patients completed the study. Median time from onset of migraine attack to scan was 6.5 h (range 4.0-15.5 h). No change...

Whole Brain Radiotherapy With Hippocampal Avoidance and Simultaneous Integrated Boost for 1-3 Brain Metastases: A Feasibility Study Using Volumetric Modulated Arc Therapy

International Nuclear Information System (INIS)

Hsu, Fred; Carolan, Hannah; Nichol, Alan; Cao, Fred; Nuraney, Nimet; Lee, Richard; Gete, Ermias; Wong, Frances; Schmuland, Moira; Heran, Manraj; Otto, Karl

2010-01-01

Purpose: To evaluate the feasibility of using volumetric modulated arc therapy (VMAT) to deliver whole brain radiotherapy (WBRT) with hippocampal avoidance and a simultaneous integrated boost (SIB) for one to three brain metastases. Methods and Materials: Ten patients previously treated with stereotactic radiosurgery for one to three brain metastases underwent repeat planning using VMAT. The whole brain prescription dose was 32.25 Gy in 15 fractions, and SIB doses to brain metastases were 63 Gy to lesions ≥2.0 cm and 70.8 Gy to lesions 2 . Plans were optimized for conformity and target coverage while minimizing hippocampal and ocular doses. Plans were evaluated on target coverage, prescription isodose to target volume ratio, conformity number, homogeneity index, and maximum dose to prescription dose ratio. Results: Ten patients had 18 metastases. Mean values for the brain metastases were as follows: conformity number = 0.73 ± 0.10, target coverage = 0.98 ± 0.01, prescription isodose to target volume = 1.34 ± 0.19, maximum dose to prescription dose ratio = 1.09 ± 0.02, and homogeneity index = 0.07 ± 0.02. For the whole brain, the mean target coverage and homogeneity index were 0.960 ± 0.002 and 0.39 ± 0.06, respectively. The mean hippocampal dose was 5.23 ± 0.39 Gy 2 . The mean treatment delivery time was 3.6 min (range, 3.3-4.1 min). Conclusions: VMAT was able to achieve adequate whole brain coverage with conformal hippocampal avoidance and radiosurgical quality dose distributions for one to three brain metastases. The mean delivery time was under 4 min.

Comparative study on the effect of radiation on whole blood and isolate red blood cells

International Nuclear Information System (INIS)

Selim, N.S.

2009-01-01

Assessment of the dielectric properties of red blood cells requires several steps for preparation and isolation from whole blood. These steps may results in changes in the cells properties, and they are time consuming . The present study aims to compare the properties of both whole blood and isolated red blood cells and the effect of gamma radiation on these properties. Adult male rats were exposed to 1, 3.5 and 7 Gy as single dose, from Cs-137 source.The studies dielectric properties, in the frequency range 40 k Hz to 5 MHz, and light scattering studies for suspensions of whole blood and isolated red blood cells from the same groups were measured. The obtained results showed that whole blood and red blood cells suspensions followed the same trend in their response to radiation, which suggests the possibility of using whole blood suspension for the evaluation of the red blood cells properties

Developmental venous anomalies: appearance on whole-brain CT digital subtraction angiography and CT perfusion

International Nuclear Information System (INIS)

Hanson, Eric H.; Roach, Cayce J.; Ringdahl, Erik N.; Wynn, Brad L.; DeChancie, Sean M.; Mann, Nathan D.; Diamond, Alan S.; Orrison, William W.

2011-01-01

Developmental venous anomalies (DVA) consist of dilated intramedullary veins that converge into a large collecting vein. The appearance of these anomalies was evaluated on whole-brain computed tomography (CT) digital subtraction angiography (DSA) and CT perfusion (CTP) studies. CT data sets of ten anonymized patients were retrospectively analyzed. Five patients had evidence of DVA and five age- and sex-matched controls were without known neurovascular abnormalities. CT angiograms, CT arterial-venous views, 4-D CT DSA and CTP maps were acquired on a dynamic volume imaging protocol on a 320-detector row CT scanner. Whole-brain CTP parameters were evaluated for cerebral blood flow (CBF), cerebral blood volume (CBV), time to peak (TTP), mean transit time (MTT), and delay. DSA was utilized to visualize DVA anatomy. Radiation dose was recorded from the scanner console. Increased CTP values were present in the DVA relative to the unaffected contralateral hemisphere of 48%, 32%, and 26%; and for the control group with matched hemispheric comparisons of 2%, -10%, and 9% for CBF, CBV, and MTT, respectively. Average effective radiation dose was 4.4 mSv. Whole-brain DSA and CTP imaging can demonstrate a characteristic appearance of altered DVA hemodynamic parameters and capture the anomalies in superior cortices of the cerebrum and the cerebellum. Future research may identify the rare subsets of patients at increased risk of adverse outcomes secondary to the altered hemodynamics to facilitate tailored imaging surveillance and application of appropriate preventive therapeutic measures. (orig.)

Developmental venous anomalies: appearance on whole-brain CT digital subtraction angiography and CT perfusion

Energy Technology Data Exchange (ETDEWEB)

Hanson, Eric H. [Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); Touro University Nevada College of Osteopathic Medicine, Henderson, NV (United States); University of Nevada Las Vegas, Department of Health Physics and Diagnostic Sciences, 4505 Maryland Parkway, Box 453037, Las Vegas, NV (United States); Amigenics, Inc, Las Vegas, NV (United States); Roach, Cayce J. [Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); University of Nevada Las Vegas, School of Life Sciences, Las Vegas, NV (United States); Ringdahl, Erik N. [University of Nevada Las Vegas, Department of Psychology, Las Vegas, NV (United States); Wynn, Brad L. [Family Medicine Spokane, Spokane, WA (United States); DeChancie, Sean M.; Mann, Nathan D. [Touro University Nevada College of Osteopathic Medicine, Henderson, NV (United States); Diamond, Alan S. [CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); Orrison, William W. [Touro University Nevada College of Osteopathic Medicine, Henderson, NV (United States); University of Nevada Las Vegas, Department of Health Physics and Diagnostic Sciences, 4505 Maryland Parkway, Box 453037, Las Vegas, NV (United States); CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); University of Nevada School of Medicine, Department of Medical Education, Reno, NV (United States)

2011-05-15

Developmental venous anomalies (DVA) consist of dilated intramedullary veins that converge into a large collecting vein. The appearance of these anomalies was evaluated on whole-brain computed tomography (CT) digital subtraction angiography (DSA) and CT perfusion (CTP) studies. CT data sets of ten anonymized patients were retrospectively analyzed. Five patients had evidence of DVA and five age- and sex-matched controls were without known neurovascular abnormalities. CT angiograms, CT arterial-venous views, 4-D CT DSA and CTP maps were acquired on a dynamic volume imaging protocol on a 320-detector row CT scanner. Whole-brain CTP parameters were evaluated for cerebral blood flow (CBF), cerebral blood volume (CBV), time to peak (TTP), mean transit time (MTT), and delay. DSA was utilized to visualize DVA anatomy. Radiation dose was recorded from the scanner console. Increased CTP values were present in the DVA relative to the unaffected contralateral hemisphere of 48%, 32%, and 26%; and for the control group with matched hemispheric comparisons of 2%, -10%, and 9% for CBF, CBV, and MTT, respectively. Average effective radiation dose was 4.4 mSv. Whole-brain DSA and CTP imaging can demonstrate a characteristic appearance of altered DVA hemodynamic parameters and capture the anomalies in superior cortices of the cerebrum and the cerebellum. Future research may identify the rare subsets of patients at increased risk of adverse outcomes secondary to the altered hemodynamics to facilitate tailored imaging surveillance and application of appropriate preventive therapeutic measures. (orig.)

BLOOD PROTEIN TRANSFERRIN POLYMOROPHISM IN BLACK BENGAL GOAT

Directory of Open Access Journals (Sweden)

Rajesh Paul

2017-12-01

Full Text Available The present investigation was carried out with an aim to explore the polymorphism of a blood protein tranferrin using starch gel electrophoresis technique in a total of unrelated 199 Black Bengal goats available in four different districts of West Bengal, India. Banding patterns of transferrin in starch gel revealed six phenovariants TfAA, TfAB, TfBC, TfBB, TfAC and TfCC comprising of three allelomorphs, TfA, TfB and TfC. The genotype frequencies were found to be observed 0.211, 0.347, 0.136, 0.106, 0.136 and 0.065 for six genotypes and the allelic frequencies were 0.452, 0.347 and 0.201 for three alleles, respectively. Result of Chi-square test revealed that the population under study was in Hardy Weinberg Equilibrium. There were polymorphism in Transferrin protein and the presence of differences among the frequencies of the three alleles by categories could be a source of genetic variation in Black Bengal goat.

Warm fresh whole blood and thoracic traumain iraq and afghanistan.

Science.gov (United States)

Keneally, Ryan J; Parsons, Andrew M; Willett, Peter B

2015-01-01

Thoracic trauma occurred in 10% of the patients seen at US military treatment facilities in Iraq and Afghanistan and 52% of those patients were transfused. Among those transfused, 281 patients received warm fresh whole blood. A previous report documented improved survival with warm fresh whole blood in patients injured in combat without stratification by injury pattern. A later report described an increase in acute lung injuries after its administration. Survivorship and warm fresh whole blood have never been analyzed in a subpopulation at highest risk for lung injuries, such as patients with thoracic trauma. There may be a heterogeneous relationship between whole blood and survival based on likelihood of a concomitant pulmonary injury. In this report, the relationship between warm fresh whole blood and survivorship was analyzed among patients at highest risk for concomitant pulmonary injuries. Patients with thoracic trauma who received a transfusion were identified in the Joint Theater Trauma Registry. Gross mortality rates were compared between whole blood recipients and patients transfused with component therapy only. The association between each blood component and mortality was determined in a regression model. The overall mortality risk was compared between warm fresh whole blood recipients and non-recipients. Patients transfused with warm fresh whole blood in addition to component therapy had a higher mortality rate than patients transfused only separated blood components (21.3% vs. 12.8%, P warm fresh whole blood in addition to component therapy was not associated with increased mortality risk compared with the transfusion of component therapy only (OR 1.247 [95% CI 0.760-2.048], P = 0.382). Patients with combat related thoracic trauma transfused with warm fresh whole blood were not at increased risk for mortality compared to those who received component therapy alone when controlling for covariates.

Brain oxygen saturation assessment in neonates using T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy

DEFF Research Database (Denmark)

Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra Ma

2017-01-01

saturation in the sagittal sinus (R(2 )= 0.49, p = 0.023), but no significant correlations could be demonstrated with frontal and whole brain cerebral blood flow. These results suggest that measuring oxygen saturation by T2-prepared blood imaging of oxygen saturation is feasible, even in neonates. Strong...... sinus. A strong linear relation was found between the oxygen saturation measured by magnetic resonance imaging and the oxygen saturation measured by near-infrared spectroscopy (R(2 )= 0.64, p ..., and magnetic resonance imaging measures of frontal cerebral blood flow, whole brain cerebral blood flow and venous oxygen saturation in the sagittal sinus (R(2 )= 0.71, 0.50, 0.65; p 

Notes on black holes and three dimensional gravity

International Nuclear Information System (INIS)

Banados, Maximo

1999-01-01

In these notes we review some relevant results on 2+1 quantum gravity. These include the Chern-Simons formulation and its affine Kac-Moody symmetry, the asymptotic algebra of Brown and Henneaux, and the statistical mechanics description of 2+1 black holes. A brief introduction to the classical and semiclassical aspects of black holes is also included. The level of the notes is basic assuming only some knowledge on Statistical Mechanics, General Relativity and Yang-Mills theory

Nano carriers for drug transport across the blood-brain barrier.

Science.gov (United States)

Li, Xinming; Tsibouklis, John; Weng, Tingting; Zhang, Buning; Yin, Guoqiang; Feng, Guangzhu; Cui, Yingde; Savina, Irina N; Mikhalovska, Lyuba I; Sandeman, Susan R; Howel, Carol A; Mikhalovsky, Sergey V

2017-01-01

Effective therapy lies in achieving a therapeutic amount of drug to the proper site in the body and then maintaining the desired drug concentration for a sufficient time interval to be clinically effective for treatment. The blood-brain barrier (BBB) hinders most drugs from entering the central nervous system (CNS) from the blood stream, leading to the difficulty of delivering drugs to the brain via the circulatory system for the treatment, diagnosis and prevention of brain diseases. Several brain drug delivery approaches have been developed, such as intracerebral and intracerebroventricular administration, intranasal delivery and blood-to-brain delivery, as a result of transient BBB disruption induced by biological, chemical or physical stimuli such as zonula occludens toxin, mannitol, magnetic heating and ultrasound, but these approaches showed disadvantages of being dangerous, high cost and unsuitability for most brain diseases and drugs. The strategy of vector-mediated blood-to-brain delivery, which involves improving BBB permeability of the drug-carrier conjugate, can minimize side effects, such as being submicrometre objects that behave as a whole unit in terms of their transport and properties, nanomaterials, are promising carrier vehicles for direct drug transport across the intact BBB as a result of their potential to enter the brain capillary endothelial cells by means of normal endocytosis and transcytosis due to their small size, as well as their possibility of being functionalized with multiple copies of the drug molecule of interest. This review provids a concise discussion of nano carriers for drug transport across the intact BBB, various forms of nanomaterials including inorganic/solid lipid/polymeric nanoparticles, nanoemulsions, quantum dots, nanogels, liposomes, micelles, dendrimers, polymersomes and exosomes are critically evaluated, their mechanisms for drug transport across the BBB are reviewed, and the future directions of this area are fully

Geometry of higher-dimensional black hole thermodynamics

International Nuclear Information System (INIS)

Aaman, Jan E.; Pidokrajt, Narit

2006-01-01

We investigate thermodynamic curvatures of the Kerr and Reissner-Nordstroem (RN) black holes in spacetime dimensions higher than four. These black holes possess thermodynamic geometries similar to those in four-dimensional spacetime. The thermodynamic geometries are the Ruppeiner geometry and the conformally related Weinhold geometry. The Ruppeiner geometry for a d=5 Kerr black hole is curved and divergent in the extremal limit. For a d≥6 Kerr black hole there is no extremality but the Ruppeiner curvature diverges where one suspects that the black hole becomes unstable. The Weinhold geometry of the Kerr black hole in arbitrary dimension is a flat geometry. For the RN black hole the Ruppeiner geometry is flat in all spacetime dimensions, whereas its Weinhold geometry is curved. In d≥5 the Kerr black hole can possess more than one angular momentum. Finally we discuss the Ruppeiner geometry for the Kerr black hole in d=5 with double angular momenta

Whole Blood PCR Amplification with Pfu DNA Polymerase and Its Application in Single-Nucleotide Polymorphism Analysis.

Science.gov (United States)

Liu, Er-Ping; Wang, Yan; He, Xiao-Hui; Guan, Jun-Jie; Wang, Jin; Qin, Zheng-Hong; Sun, Wan-Ping

2015-11-01

Point-of-care genetic analysis may require polymerase chain reaction (PCR) to be carried out on whole blood. However, human blood contains natural inhibitors of PCR such as hemoglobin, immunoglobulin G, lactoferrin, and proteases, as well as anticoagulant agents, including EDTA and heparin that can reduce whole blood PCR efficiency. Our purpose was to develop a highly specific, direct whole blood single-nucleotide polymorphism (SNP) analysis method based on allele-specific (AS) PCR that is mediated by Pfu DNA polymerase and phosphorothioate-modified AS primers. At high Mg(2+) concentrations, Pfu DNA polymerase efficiently amplified genomic DNA in a reaction solution containing up to 14% whole blood. Among the three anticoagulants tested, Pfu DNA polymerase showed the highest activity with sodium citrate. Meanwhile, Triton X-100 and betaine inhibited Pfu DNA polymerase activity in whole blood PCR, whereas trehalose had virtually no effect. These findings provided for the development of a low-cost, simple, and fast direct whole blood genotyping method that uses Pfu DNA polymerase combined with phosphorothioate AS primers for CYP2C9*3 and VKORC1(-1639) loci. With its high DNA amplification efficiency and tolerance of various blood conditions, Pfu DNA polymerase can be used in clinical laboratories to analyze SNPs in whole blood samples.

Three-dimensional visualization of functional brain tissue and functional magnetic resonance imaging-integrated neuronavigation in the resection of brain tumor adjacent to motor cortex

International Nuclear Information System (INIS)

Han Tong; Cui Shimin; Tong Xiaoguang; Liu Li; Xue Kai; Liu Meili; Liang Siquan; Zhang Yunting; Zhi Dashi

2011-01-01

Objective: To assess the value of three -dimensional visualization of functional brain tissue and the functional magnetic resonance imaging (fMRI)-integrated neuronavigation in the resection of brain tumor adjacent to motor cortex. Method: Sixty patients with tumor located in the central sulcus were enrolled. Thirty patients were randomly assigned to function group and 30 to control group. Patients in function group underwent fMRI to localize the functional brain tissues. Then the function information was transferred to the neurosurgical navigator. The patients in control group underwent surgery with navigation without function information. The therapeutic effect, excision rate. improvement of motor function, and survival quality during follow-up were analyzed. Result: All patients in function group were accomplished visualization of functional brain tissues and fMRI-integrated neuronavigation. The locations of tumors, central sulcus and motor cortex were marked during the operation. The fMRI -integrated information played a great role in both pre- and post-operation. Pre-operation: designing the location of the skin flap and window bone, determining the relationship between the tumor and motor cortex, and designing the pathway for the resection. Post- operation: real-time navigation of relationship between the tumor and motor cortex, assisting to localize the motor cortex using interoperation ultra-sound for correcting the displacement by the CSF outflow and collapsing tumor. The patients in the function group had better results than the patients in the control group in therapeutic effect (u=2.646, P=0.008), excision rate (χ = 7.200, P<0.01), improvement of motor function (u=2.231, P=0.026), and survival quality (KPS u c = 2.664, P=0.008; Zubrod -ECOG -WHO u c =2.135, P=0.033). Conclusions: Using preoperative three -dimensional visualization of cerebral function tissue and the fMRI-integrated neuronavigation technology, combining intraoperative accurate

Three-dimensional architecture of the whole human soleus muscle in vivo

Science.gov (United States)

Finni, Taija; D’Souza, Arkiev; Eguchi, Junya; Clarke, Elizabeth C.; Herbert, Robert D.

2018-01-01

Background Most data on the architecture of the human soleus muscle have been obtained from cadaveric dissection or two-dimensional ultrasound imaging. We present the first comprehensive, quantitative study on the three-dimensional anatomy of the human soleus muscle in vivo using diffusion tensor imaging (DTI) techniques. Methods We report three-dimensional fascicle lengths, pennation angles, fascicle curvatures, physiological cross-sectional areas and volumes in four compartments of the soleus at ankle joint angles of 69 ± 12° (plantarflexion, short muscle length; average ± SD across subjects) and 108 ± 7° (dorsiflexion, long muscle length) of six healthy young adults. Microdissection and three-dimensional digitisation on two cadaveric muscles corroborated the compartmentalised structure of the soleus, and confirmed the validity of DTI-based muscle fascicle reconstructions. Results The posterior compartments of the soleus comprised 80 ± 5% of the total muscle volume (356 ± 58 cm3). At the short muscle length, the average fascicle length, pennation angle and curvature was 37 ± 8 mm, 31 ± 3° and 17 ± 4 /m, respectively. We did not find differences in fascicle lengths between compartments. However, pennation angles were on average 12° larger (p < 0.01) in the posterior compartments than in the anterior compartments. For every centimetre that the muscle-tendon unit lengthened, fascicle lengths increased by 3.7 ± 0.8 mm, pennation angles decreased by −3.2 ± 0.9° and curvatures decreased by −2.7 ± 0.8 /m. Fascicles in the posterior compartments rotated almost twice as much as in the anterior compartments during passive lengthening. Discussion The homogeneity in fascicle lengths and inhomogeneity in pennation angles of the soleus may indicate a functionally different role for the anterior and posterior compartments. The data and techniques presented here demonstrate how DTI can be used to obtain detailed, quantitative measurements of the

Time-dependent perturbations in two-dimensional string black holes

CERN Document Server

Diamandis, G A; Maintas, X N; Mavromatos, Nikolaos E

1992-01-01

We discuss time-dependent perturbations (induced by matter fields) of a black-hole background in tree-level two-dimensional string theory. We analyse the linearized case and show the possibility of having black-hole solutions with time-dependent horizons. The latter exist only in the presence of time-dependent `tachyon' matter fields, which constitute the only propagating degrees of freedom in two-dimensional string theory. For real tachyon field configurations it is not possible to obtain solutions with horizons shrinking to a point. On the other hand, such a possibility seems to be realized in the case of string black-hole models formulated on higher world-sheet genera. We connect this latter result with black hole evaporation/decay at a quantum level.}

Modeling the nitrogen cycling and plankton productivity in the Black Sea using a three-dimensional interdisciplinary model

NARCIS (Netherlands)

Grégoire, M.; Soetaert, K.E.R.; Nezlin, N.; Kostianoy, A.

2004-01-01

A six-compartment ecosystem model defined by a simple nitrogen cycle is coupled with a general circulation model in the Black Sea so as to examine the seasonal variability of the ecohydrodynamics. Model results show that the annual cycle of the biological productivity of the whole basin is

Brain-computer interfaces increase whole-brain signal to noise.

Science.gov (United States)

Papageorgiou, T Dorina; Lisinski, Jonathan M; McHenry, Monica A; White, Jason P; LaConte, Stephen M

2013-08-13

Brain-computer interfaces (BCIs) can convert mental states into signals to drive real-world devices, but it is not known if a given covert task is the same when performed with and without BCI-based control. Using a BCI likely involves additional cognitive processes, such as multitasking, attention, and conflict monitoring. In addition, it is challenging to measure the quality of covert task performance. We used whole-brain classifier-based real-time functional MRI to address these issues, because the method provides both classifier-based maps to examine the neural requirements of BCI and classification accuracy to quantify the quality of task performance. Subjects performed a covert counting task at fast and slow rates to control a visual interface. Compared with the same task when viewing but not controlling the interface, we observed that being in control of a BCI improved task classification of fast and slow counting states. Additional BCI control increased subjects' whole-brain signal-to-noise ratio compared with the absence of control. The neural pattern for control consisted of a positive network comprised of dorsal parietal and frontal regions and the anterior insula of the right hemisphere as well as an expansive negative network of regions. These findings suggest that real-time functional MRI can serve as a platform for exploring information processing and frontoparietal and insula network-based regulation of whole-brain task signal-to-noise ratio.

Evaluation of three glucometers for whole blood glucose measurements at the point of care in preterm or low-birth-weight infants.

Science.gov (United States)

Hwang, Joon Ho; Sohn, Yong-Hak; Chang, Seong-Sil; Kim, Seung Yeon

2015-08-01

We evaluated three blood glucose self-monitoring for measuring whole blood glucose levels in preterm and low-birth-weight infants. Between December 1, 2012 and March 31, 2013, 230 blood samples were collected from 50 newborns, who weighed, ≤2,300 g or were ≤36 weeks old, in the the neonatal intensive care unit of Eulji University Hospital. Three blood glucose self-monitoring (A: Precision Pcx, Abbott; B: One-Touch Verio, Johnson & Johnson; C: LifeScan SureStep Flexx, Johnson & Johnson) were used for the blood glucose measurements. The results were compared to those obtained using laboratory equipment (D: Advia chemical analyzer, Siemens Healthcare Diagnostics Inc.). The correlation coefficients between laboratory equipment and the three blood glucose self-monitoring (A, B, and C) were found to be 0.888, 0.884, and 0.900, respectively. For glucose levels≤60 mg/dL, the correlation coefficients were 0.674, 0.687, and 0.679, respectively. For glucose levels>60 mg/dL, the correlation coefficients were 0.822, 0.819, and 0.839, respectively. All correlation coefficients were statistically significant. And the values from the blood glucose self-monitoring were not significantly different from the value of the laboratory equipment , after correcting for each device's average value (P>0.05). When using laboratory equipment (blood glucose ≤60 mg/dL), each device had a sensitivity of 0.458, 0.604, and 0.688 and a specificity of 0.995, 0.989, and 0.989, respectively. Significant difference is not found between three blood glucose self-monitoring and laboratory equipment. But correlation between the measured values from blood glucose self-monitoring and laboratory equipment is lower in preterm or low-birth-weight infants than adults.

Black holes of dimensionally continued gravity coupled to Born-Infeld electromagnetic field

Science.gov (United States)

Meng, Kun; Yang, Da-Bao

2018-05-01

In this paper, for dimensionally continued gravity coupled to Born-Infeld electromagnetic field, we construct topological black holes in diverse dimensions and construct dyonic black holes in general even dimensions. We study thermodynamics of the black holes and obtain first laws. We study thermal phase transitions of the black holes in T-S plane and find van der Waals-like phase transitions for even-dimensional spherical black holes, such phase transitions are not found for other types of black holes constructed in this paper.

Is human blood a good surrogate for brain tissue in transcriptional studies?

Directory of Open Access Journals (Sweden)

van den Berg Leonard H

2010-10-01

Full Text Available Abstract Background Since human brain tissue is often unavailable for transcriptional profiling studies, blood expression data is frequently used as a substitute. The underlying hypothesis in such studies is that genes expressed in brain tissue leave a transcriptional footprint in blood. We tested this hypothesis by relating three human brain expression data sets (from cortex, cerebellum and caudate nucleus to two large human blood expression data sets (comprised of 1463 individuals. Results We found mean expression levels were weakly correlated between the brain and blood data (r range: [0.24,0.32]. Further, we tested whether co-expression relationships were preserved between the three brain regions and blood. Only a handful of brain co-expression modules showed strong evidence of preservation and these modules could be combined into a single large blood module. We also identified highly connected intramodular "hub" genes inside preserved modules. These preserved intramodular hub genes had the following properties: first, their expression levels tended to be significantly more heritable than those from non-preserved intramodular hub genes (p -90; second, they had highly significant positive correlations with the following cluster of differentiation genes: CD58, CD47, CD48, CD53 and CD164; third, a significant number of them were known to be involved in infection mechanisms, post-transcriptional and post-translational modification and other basic processes. Conclusions Overall, we find transcriptome organization is poorly preserved between brain and blood. However, the subset of preserved co-expression relationships characterized here may aid future efforts to identify blood biomarkers for neurological and neuropsychiatric diseases when brain tissue samples are unavailable.

A plastic surgery application in evolution: three-dimensional printing.

Science.gov (United States)

Gerstle, Theodore L; Ibrahim, Ahmed M S; Kim, Peter S; Lee, Bernard T; Lin, Samuel J

2014-02-01

Three-dimensional printing represents an evolving technology still in its infancy. Currently, individuals and small business entities have the ability to manufacture physical objects from digital renderings, computer-aided design, and open source files. Design modifications and improvements in extrusion methods have made this technology much more affordable. This article explores the potential uses of three-dimensional printing in plastic surgery. A review was performed detailing the known uses of three-dimensional printing in medicine. The potential applications of three-dimensional printing in plastic surgery are discussed. Various applications for three-dimensional printing technology have emerged in medicine, including printing organs, printing body parts, bio-printing, and computer-aided tissue engineering. In plastic surgery, these tools offer various prospective applications for surgical planning, resident education, and the development of custom prosthetics. Numerous applications exist in medicine, including the printing of devices, implants, tissue replacements, and even whole organs. Plastic surgeons may likely find this technology indispensable in surgical planning, education, and prosthetic device design and development in the near future.

T2 Magnetic Resonance Assay-Based Direct Detection of Three Lyme Disease-Related Borrelia Species in Whole-Blood Samples.

Science.gov (United States)

Snyder, Jessica L; Giese, Heidi; Bandoski-Gralinski, Cheryl; Townsend, Jessica; Jacobson, Beck E; Shivers, Robert; Schotthoefer, Anna M; Fritsche, Thomas R; Green, Clayton; Callister, Steven M; Branda, John A; Lowery, Thomas J

2017-08-01

In early Lyme disease (LD), serologic testing is insensitive and seroreactivity may reflect active or past infection. In this study, we evaluated a novel assay for the direct detection of three species of Borrelia spirochetes in whole blood. The T2 magnetic resonance (T2MR) assay platform was used to amplify Borrelia DNA released from intact spirochetes and to detect amplicon. Analytical sensitivity was determined from blood spiked with known concentrations of spirochetes, and the assay's limit of detection was found to be in the single-cell-per-milliliter range: 5 cells/ml for B. afzelii and 8 cells/ml for Borrelia burgdorferi and Borrelia garinii Clinical samples ( n = 66) from confirmed or suspected early LD patients were also analyzed. B. burgdorferi was detected using T2MR in 2/2 (100%) of blood samples from patients with confirmed early LD, based on the presence of erythema migrans and documentation of seroconversion or a positive real-time blood PCR. T2MR detected B. burgdorferi in blood samples from 17/54 (31%) of patients with probable LD, based on the presence of erythema migrans without documented seroconversion or of documented seroconversion in patients with a compatible clinical syndrome but without erythema migrans. Out of 21 clinical samples tested by real-time PCR, only 1 was positive and 13 were negative with agreement with T2MR. An additional 7 samples that were negative by real-time PCR were positive with T2MR. Therefore, T2MR enables a low limit of detection (LoD) for Borrelia spp. in whole blood samples and is able to detect B. burgdorferi in clinical samples. Copyright © 2017 American Society for Microbiology.

Management of high blood pressure in Blacks: an update of the International Society on Hypertension in Blacks consensus statement.

Science.gov (United States)

Flack, John M; Sica, Domenic A; Bakris, George; Brown, Angela L; Ferdinand, Keith C; Grimm, Richard H; Hall, W Dallas; Jones, Wendell E; Kountz, David S; Lea, Janice P; Nasser, Samar; Nesbitt, Shawna D; Saunders, Elijah; Scisney-Matlock, Margaret; Jamerson, Kenneth A

2010-11-01

Since the first International Society on Hypertension in Blacks consensus statement on the "Management of High Blood Pressure in African American" in 2003, data from additional clinical trials have become available. We reviewed hypertension and cardiovascular disease prevention and treatment guidelines, pharmacological hypertension clinical end point trials, and blood pressure-lowering trials in blacks. Selected trials without significant black representation were considered. In this update, blacks with hypertension are divided into 2 risk strata, primary prevention, where elevated blood pressure without target organ damage, preclinical cardiovascular disease, or overt cardiovascular disease for whom blood pressure consistently secondary prevention, where elevated blood pressure with target organ damage, preclinical cardiovascular disease, and/or a history of cardiovascular disease, for whom blood pressure consistently blood pressure is ≤10 mm Hg above target levels, monotherapy with a diuretic or calcium channel blocker is preferred. When blood pressure is >15/10 mm Hg above target, 2-drug therapy is recommended, with either a calcium channel blocker plus a renin-angiotensin system blocker or, alternatively, in edematous and/or volume-overload states, with a thiazide diuretic plus a renin-angiotensin system blocker. Effective multidrug therapeutic combinations through 4 drugs are described. Comprehensive lifestyle modifications should be initiated in blacks when blood pressure is ≥115/75 mm Hg. The updated International Society on Hypertension in Blacks consensus statement on hypertension management in blacks lowers the minimum target blood pressure level for the lowest-risk blacks, emphasizes effective multidrug regimens, and de-emphasizes monotherapy.

Three-dimensional brain metabolic imaging in patients with toxic encephalopathy

International Nuclear Information System (INIS)

Callender, T.J.; Duhon, D.; Ristovv, M.; Morrow, L.; Subramanian, K.

1993-01-01

Thirty-three workers, ages 24 to 63, developed clinical toxic encephalopathy after exposure to neurotoxins and were studied by SPECT brain scans. Five were exposed to pesticides, 13 were acutely exposed to mixtures of solvents, 8 were chronically exposed to mixtures of hazardous wastes that contained organic solvents, 2 were acutely exposed to phosgene and other toxins, and 5 had exposures to hydrogen sulfide. Twenty-nine had neuropsychological testing and all had a medical history and physical. Of the workers who had a clinical diagnosis of toxic encephalopathy, 31 (93.9%) had abnormal SPECT brain scans with the most frequent areas of abnormality being temporal lobes (67.7%), frontal lobes (61.3%), basal ganglia (45.2%), thalamus (29.0%), parietal lobes (12.9%), motorstrip (9.68%), cerebral hemisphere (6.45%), occipital lobes (3.23%), and caudate nucleus (3.23%). Twenty-three out of 29 (79.3%) neuropsychological evaluations were abnormal. Other modalities when performed included the following percentages of abnormals: NCV, 33.3%; CPT sensory nerve testing, 91.3%, vestibular function testing, 71.4%; olfactory testing, 89.2%; sleep EEG analysis, 85.7%; EEG, 8.33%; CT, 7.14%; and MRI brain scans, 28.6%. The complex of symptoms seen in toxic encephalopathy implies dysfunction involving several CNS regions. This series of patients adds to the previous experience of brain metabolic imaging and demonstrates that certain areas of the brain are typically affected despite differences in toxin structure, that these lesions can be globally defined by SPECT/PET brain scans, that these lesions correlate well with clinical and neuropsychological testing, and that such testing is a useful adjunct to previous methods. EEG and structural brain imaging such as CT and MRI are observed to have poor sensitivity in this type of patient. 32 refs., 5 tabs

Interior design of a two-dimensional semiclassical black hole

Science.gov (United States)

Levanony, Dana; Ori, Amos

2009-10-01

We look into the inner structure of a two-dimensional dilatonic evaporating black hole. We establish and employ the homogenous approximation for the black-hole interior. Two kinds of spacelike singularities are found inside the black hole, and their structure is investigated. We also study the evolution of spacetime from the horizon to the singularity.

Interior design of a two-dimensional semiclassical black hole

International Nuclear Information System (INIS)

Levanony, Dana; Ori, Amos

2009-01-01

We look into the inner structure of a two-dimensional dilatonic evaporating black hole. We establish and employ the homogenous approximation for the black-hole interior. Two kinds of spacelike singularities are found inside the black hole, and their structure is investigated. We also study the evolution of spacetime from the horizon to the singularity.

Three dimensional illustrating - three-dimensional vision and deception of sensibility

Directory of Open Access Journals (Sweden)

Anita Gánóczy

2009-03-01

Full Text Available The wide-spread digital photography and computer use gave the opportunity for everyone to make three-dimensional pictures and to make them public. The new opportunities with three-dimensional techniques give chance for the birth of new artistic photographs. We present in detail the biological roots of three-dimensional visualization, the phenomena of movement parallax, which can be used efficiently in making three-dimensional graphics, the Zöllner- and Corridor-illusion. There are present in this paper the visual elements, which contribute to define a plane two-dimensional image in three-dimension: coherent lines, the covering, the measurement changes, the relative altitude state, the abatement of detail profusion, the shadings and the perspective effects of colors.

A mathematical model of coronary blood flow control: simulation of patient-specific three-dimensional hemodynamics during exercise

Science.gov (United States)

Lau, Kevin D.; Asrress, Kaleab N.; Redwood, Simon R.; Figueroa, C. Alberto

2016-01-01

This work presents a mathematical model of the metabolic feedback and adrenergic feedforward control of coronary blood flow that occur during variations in the cardiac workload. It is based on the physiological observations that coronary blood flow closely follows myocardial oxygen demand, that myocardial oxygen debts are repaid, and that control oscillations occur when the system is perturbed and so are phenomenological in nature. Using clinical data, we demonstrate that the model can provide patient-specific estimates of coronary blood flow changes between rest and exercise, requiring only the patient's heart rate and peak aortic pressure as input. The model can be used in zero-dimensional lumped parameter network studies or as a boundary condition for three-dimensional multidomain Navier-Stokes blood flow simulations. For the first time, this model provides feedback control of the coronary vascular resistance, which can be used to enhance the physiological accuracy of any hemodynamic simulation, which includes both a heart model and coronary arteries. This has particular relevance to patient-specific simulation for which heart rate and aortic pressure recordings are available. In addition to providing a simulation tool, under our assumptions, the derivation of our model shows that β-feedforward control of the coronary microvascular resistance is a mathematical necessity and that the metabolic feedback control must be dependent on two error signals: the historical myocardial oxygen debt, and the instantaneous myocardial oxygen deficit. PMID:26945076

A mathematical model of coronary blood flow control: simulation of patient-specific three-dimensional hemodynamics during exercise.

Science.gov (United States)

Arthurs, Christopher J; Lau, Kevin D; Asrress, Kaleab N; Redwood, Simon R; Figueroa, C Alberto

2016-05-01

This work presents a mathematical model of the metabolic feedback and adrenergic feedforward control of coronary blood flow that occur during variations in the cardiac workload. It is based on the physiological observations that coronary blood flow closely follows myocardial oxygen demand, that myocardial oxygen debts are repaid, and that control oscillations occur when the system is perturbed and so are phenomenological in nature. Using clinical data, we demonstrate that the model can provide patient-specific estimates of coronary blood flow changes between rest and exercise, requiring only the patient's heart rate and peak aortic pressure as input. The model can be used in zero-dimensional lumped parameter network studies or as a boundary condition for three-dimensional multidomain Navier-Stokes blood flow simulations. For the first time, this model provides feedback control of the coronary vascular resistance, which can be used to enhance the physiological accuracy of any hemodynamic simulation, which includes both a heart model and coronary arteries. This has particular relevance to patient-specific simulation for which heart rate and aortic pressure recordings are available. In addition to providing a simulation tool, under our assumptions, the derivation of our model shows that β-feedforward control of the coronary microvascular resistance is a mathematical necessity and that the metabolic feedback control must be dependent on two error signals: the historical myocardial oxygen debt, and the instantaneous myocardial oxygen deficit. Copyright © 2016 the American Physiological Society.

Accelerated time-resolved three-dimensional MR velocity mapping of blood flow patterns in the aorta using SENSE and k-t BLAST

International Nuclear Information System (INIS)

Stadlbauer, Andreas; Riet, Wilma van der; Crelier, Gerard; Salomonowitz, Erich

2010-01-01

Purpose: To assess the feasibility and potential limitations of the acceleration techniques SENSE and k-t BLAST for time-resolved three-dimensional (3D) velocity mapping of aortic blood flow. Furthermore, to quantify differences in peak velocity versus heart phase curves. Materials and methods: Time-resolved 3D blood flow patterns were investigated in eleven volunteers and two patients suffering from aortic diseases with accelerated PC-MR sequences either in combination with SENSE (R = 2) or k-t BLAST (6-fold). Both sequences showed similar data acquisition times and hence acceleration efficiency. Flow-field streamlines were calculated and visualized using the GTFlow software tool in order to reconstruct 3D aortic blood flow patterns. Differences between the peak velocities from single-slice PC-MRI experiments using SENSE 2 and k-t BLAST 6 were calculated for the whole cardiac cycle and averaged for all volunteers. Results: Reconstruction of 3D flow patterns in volunteers revealed attenuations in blood flow dynamics for k-t BLAST 6 compared to SENSE 2 in terms of 3D streamlines showing fewer and less distinct vortices and reduction in peak velocity, which is caused by temporal blurring. Solely by time-resolved 3D MR velocity mapping in combination with SENSE detected pathologic blood flow patterns in patients with aortic diseases. For volunteers, we found a broadening and flattering of the peak velocity versus heart phase diagram between the two acceleration techniques, which is an evidence for the temporal blurring of the k-t BLAST approach. Conclusion: We demonstrated the feasibility of SENSE and detected potential limitations of k-t BLAST when used for time-resolved 3D velocity mapping. The effects of higher k-t BLAST acceleration factors have to be considered for application in 3D velocity mapping.

Periventricular Nodular Heterotopia: Detection of Abnormal Microanatomic Fiber Structures with Whole-Brain Diffusion MR Imaging Tractography.

Science.gov (United States)

Farquharson, Shawna; Tournier, J-Donald; Calamante, Fernando; Mandelstam, Simone; Burgess, Rosemary; Schneider, Michal E; Berkovic, Samuel F; Scheffer, Ingrid E; Jackson, Graeme D; Connelly, Alan

2016-12-01

Purpose To investigate whether it is possible in patients with periventricular nodular heterotopia (PVNH) to detect abnormal fiber projections that have only previously been reported in the histopathology literature. Materials and Methods Whole-brain diffusion-weighted (DW) imaging data from 14 patients with bilateral PVNH and 14 age- and sex-matched healthy control subjects were prospectively acquired by using 3.0-T magnetic resonance (MR) imaging between August 1, 2008, and December 5, 2012. All participants provided written informed consent. The DW imaging data were processed to generate whole-brain constrained spherical deconvolution (CSD)-based tractography data and super-resolution track-density imaging (TDI) maps. The tractography data were overlaid on coregistered three-dimensional T1-weighted images to visually assess regions of heterotopia. A panel of MR imaging researchers independently assessed each case and indicated numerically (no = 1, yes = 2) as to the presence of abnormal fiber tracks in nodular tissue. The Fleiss κ statistical measure was applied to assess the reader agreement. Results Abnormal fiber tracks emanating from one or more regions of heterotopia were reported by all four readers in all 14 patients with PVNH (Fleiss κ = 1). These abnormal structures were not visible on the tractography data from any of the control subjects and were not discernable on the conventional T1-weighted images of the patients with PVNH. Conclusion Whole-brain CSD-based fiber tractography and super-resolution TDI mapping reveals abnormal fiber projections in nodular tissue suggestive of abnormal organization of white matter (with abnormal fibers both within nodules and projecting to the surrounding white matter) in patients with bilateral PVNH. © RSNA, 2016.

Combination of three-dimensional laser scanning and digital photogrammetric shoot for fixing and measurement of architectural monuments

OpenAIRE

S.V. Tiurin; S.G. Tihonov

2010-01-01

Several variants of architectural monument fixing using photogrammetric method are considered: black-and-white and colour three-dimensional point models; black-and-white and colour orthophotomaps in format SPO; black-and-white and colour orthophotomaps in standard raster formats. For different aims authors recommend corresponding data formats.

Evidence for altered transport of insulin across the blood-brain barrier in insulin-resistant humans.

Science.gov (United States)

Heni, Martin; Schöpfer, Patricia; Peter, Andreas; Sartorius, Tina; Fritsche, Andreas; Synofzik, Matthis; Häring, Hans-Ulrich; Maetzler, Walter; Hennige, Anita M

2014-08-01

Eating behavior, body weight regulation, peripheral glucose metabolism, and cognitive function depend on adequate insulin action in the brain, and recent studies in humans suggested that impaired insulin action in the brain emerges upon fat intake, obesity, and genetic variants. As insulin enters into the brain in a receptor-mediated fashion, we hypothesized that whole-body insulin sensitivity might affect the transport of insulin into the brain and contribute to the aversive effect of insulin resistance in the central nervous system. In this study, we aimed to determine the ratio of insulin in the cerebrospinal fluid and serum to whole-body insulin sensitivity. Healthy human subjects participated in an oral glucose tolerance test to determine whole-body insulin sensitivity and underwent lumbar puncture. Blood and CSF concentrations of insulin were significantly correlated. The CSF/serum ratio for insulin was significantly associated with whole body insulin sensitivity with reduced insulin transported into the CSF in insulin-resistant subjects. Together, our data suggest that transport of insulin into the CSF relates to peripheral insulin sensitivity and impairs insulin action in the brain. This underlines the need for sensitizing measures in insulin-resistant subjects.

A microfluidic chip for direct and rapid trapping of white blood cells from whole blood

Science.gov (United States)

Chen, Jingdong; Chen, Di; Yuan, Tao; Xie, Yao; Chen, Xiang

2013-01-01

Blood analysis plays a major role in medical and science applications and white blood cells (WBCs) are an important target of analysis. We proposed an integrated microfluidic chip for direct and rapid trapping WBCs from whole blood. The microfluidic chip consists of two basic functional units: a winding channel to mix and arrays of two-layer trapping structures to trap WBCs. Red blood cells (RBCs) were eliminated through moving the winding channel and then WBCs were trapped by the arrays of trapping structures. We fabricated the PDMS (polydimethylsiloxane) chip using soft lithography and determined the critical flow velocities of tartrazine and brilliant blue water mixing and whole blood and red blood cell lysis buffer mixing in the winding channel. They are 0.25 μl/min and 0.05 μl/min, respectively. The critical flow velocity of the whole blood and red blood cell lysis buffer is lower due to larger volume of the RBCs and higher kinematic viscosity of the whole blood. The time taken for complete lysis of whole blood was about 85 s under the flow velocity 0.05 μl/min. The RBCs were lysed completely by mixing and the WBCs were trapped by the trapping structures. The chip trapped about 2.0 × 103 from 3.3 × 103 WBCs. PMID:24404026

All or nothing: On the small fluctuations of two-dimensional string theoretic black holes

Energy Technology Data Exchange (ETDEWEB)

Gilbert, Gerald [Univ. of Maryland, College Park, MD (United States); Raiten, Eric [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

1992-10-01

A comprehensive analysis of small fluctuations about two-dimensional string-theoretic and string-inspired black holes is presented. It is shown with specific examples that two-dimensional black holes behave in a radically different way from all known black holes in four dimensions. For both the SL(2,R)/U(1) black hole and the two-dimensional black hole coupled to a massive dilaton with constant field strength, it is shown that there are a {\\it continuous infinity} of solutions to the linearized equations of motion, which are such that it is impossible to ascertain the classical linear response. It is further shown that the two-dimensional black hole coupled to a massive, linear dilaton admits {\\it no small fluctuations at all}. We discuss possible implications of our results for the Callan-Giddings-Harvey-Strominger black hole.

Species differences in blood-brain barrier transport of three positron emission tomography radioligands with emphasis on P-glycoprotein transport

DEFF Research Database (Denmark)

Syvanen, S.; Lindhe, O.; Palner, M.

2009-01-01

preclinical data to humans. Compounds found to be P-gp substrates in rodents are likely to also be substrates in higher species, but sufficient blood-brain barrier permeability may be retained in humans to allow the compound to act at intracerebral targets Udgivelsesdato: 2009/3......Species differences occur in the brain concentrations of drugs, but the reasons for these differences are not yet apparent. This study was designed to compare brain uptake of three radiolabeled P-glycoprotein (P-gp) substrates across species using positron emission tomography. Brain concentrations...... and brain-to-plasma ratios were compared; [(11)C]verapamil in rats, guinea pigs, and monkeys; [(11)C](S)-(2-methoxy-5-(5-trifluoromethyltetrazol-1-yl)-phenylmethylamino )-2(S)-phenylpiperidine (GR205171) in rats, guinea pigs, monkeys, and humans; and [(18)F]altanserin in rats, minipigs, and humans...

Global embedding of D-dimensional black holes with a cosmological constant in Minkowskian spacetimes: Matching between Hawking temperature and Unruh temperature

International Nuclear Information System (INIS)

Santos, Nuno Loureiro; Dias, Oscar J.C.; Lemos, Jose P.S.

2004-01-01

We study the matching between the Hawking temperature of a large class of static D-dimensional black holes and the Unruh temperature of the corresponding higher dimensional Rindler spacetime. In order to accomplish this task we find the global embedding of the D-dimensional black holes into a higher dimensional Minkowskian spacetime, called the global embedding Minkowskian spacetime procedure (GEMS procedure). These global embedding transformations are important on their own, since they provide a powerful tool that simplifies the study of black hole physics by working instead, but equivalently, in an accelerated Rindler frame in a flat background geometry. We discuss neutral and charged Tangherlini black holes with and without cosmological constant, and in the negative cosmological constant case, we consider the three allowed topologies for the horizons (spherical, cylindrical/toroidal, and hyperbolic)

Viscoelastic capillary flow: the case of whole blood

Directory of Open Access Journals (Sweden)

David Rabaud

2016-07-01

Full Text Available The dynamics of spontaneous capillary flow of Newtonian fluids is well-known and can be predicted by the Lucas-Washburn-Rideal (LWR law. However a wide variety of viscoelastic fluids such as alginate, xanthan and blood, does not exhibit the same Newtonian behavior.In this work we consider the Herschel-Bulkley (HB rheological model and Navier-Stokes equation to derive a generic expression that predicts the capillary flow of non-Newtonian fluids. The Herschel-Bulkley rheological model encompasses a wide variety of fluids, including the Power-law fluids (also called Ostwald fluids, the Bingham fluids and the Newtonian fluids. It will be shown that the proposed equation reduces to the Lucas-Washburn-Rideal law for Newtonian fluids and to the Weissenberg-Rabinowitsch-Mooney (WRM law for power-law fluids. Although HB model cannot reduce to Casson’s law, which is often used to model whole blood rheology, HB model can fit the whole blood rheology with the same accuracy.Our generalized expression for the capillary flow of non-Newtonian fluid was used to accurately fit capillary flow of whole blood. The capillary filling of a cylindrical microchannel by whole blood was monitored. The blood first exhibited a Newtonian behavior, then after 7 cm low shear stress and rouleaux formation made LWR fails to fit the data: the blood could not be considered as Newtonian anymore. This non-Newtonian behavior was successfully fit by the proposed equation.

Cerebral blood flow of the non-affected brain in patients with malignant brain tumors as studied by SPECT

International Nuclear Information System (INIS)

Araki, Yuzo; Imao, Yukinori; Hirata, Toshifumi; Ando, Takashi; Sakai, Noboru; Yamada, Hiroshi

1990-01-01

In 40 patients (age range, 20-69 years) receiving radiation and chemotherapy for brain tumors, the mean cerebral blood flow (mCBF) in the non-affected area has been examined by single photon emission CT (SPECT) with Xe-133. Forty volunteers (age range, 25-82 years) served as controls. Although mCBF during external irradiation was transiently increased, it was significantly decreased at 3 months after beginning of external irradiation compared with that in the control group. Factors responsible for the decrease in mCBF were radiation doses, lesion volume, the degree of cerebral atrophy, and age; this was more pronounced when chemotherapy such as ACNU was combined with radiation. A decreased mCBF was independent of intraoperative radiation combined with external radiation and either local or whole brain irradiation. SPECT with Xe-133 was useful in determining minute changes in cerebral blood flow that precedes parenchymal brain damage. (N.K.)

Transcriptome analysis in whole blood reveals increased microbial diversity in schizophrenia

NARCIS (Netherlands)

Olde Loohuis, Loes M.; Mangul, Serghei; Ori, Anil P.S.; Jospin, Guillaume; Koslicki, David; Yang, Harry Taegyun; Wu, Timothy; Boks, Marco P.; Lomen-Hoerth, Catherine; Wiedau-Pazos, Martina; Cantor, Rita M.; Vos, De Willem M.; Kahn, René S.; Eskin, Eleazar; Ophoff, Roel A.

2018-01-01

The role of the human microbiome in health and disease is increasingly appreciated. We studied the composition of microbial communities present in blood across 192 individuals, including healthy controls and patients with three disorders affecting the brain: schizophrenia, amyotrophic lateral

Emission computerized-tomography and determination of local brain function

International Nuclear Information System (INIS)

Kuhl, D.E.; Alavi, A.; Reivich, M.; Edwards, R.Q.; Fenton, C.A.; Zimmerman, R.A.

1975-01-01

Methods for the three dimensional reconstruction of /sup 99m/Tc brain scans are described. The diagnostic advantages of computerized tomography in the localization of brain tumors and in measurements of local cerebral blood flow are discussed. (U.S.)

Tachyon hair on two-dimensional black holes

International Nuclear Information System (INIS)

Peet, A.; Susskind, L.; Thorlacius, L.

1993-01-01

Static black holes in two-dimensional string theory can carry tachyon hair. Configurations which are nonsingular at the event horizon have a nonvanishing asymptotic energy density. Such solutions can be smoothly extended through the event horizon and have a nonvanishing energy flux emerging from the past singularity. Dynamical processes will not change the amount of tachyon hair on a black hole. In particular, there will be no tachyon hair on a black hole formed in gravitational collapse if the initial geometry is the linear dilaton vacuum. There also exist static solutions with a finite total energy, which have singular event horizons. Simple dynamical arguments suggest that black holes formed in gravitational collapse will not have tachyon hair of this type

The existence and regularity of time-periodic solutions to the three-dimensional Navier–Stokes equations in the whole space

International Nuclear Information System (INIS)

Kyed, Mads

2014-01-01

The existence, uniqueness and regularity of time-periodic solutions to the Navier–Stokes equations in the three-dimensional whole space are investigated. We consider the Navier–Stokes equations with a non-zero drift term corresponding to the physical model of a fluid flow around a body that moves with a non-zero constant velocity. The existence of a strong time-periodic solution is shown for small time-periodic data. It is further shown that this solution is unique in a large class of weak solutions that can be considered physically reasonable. Finally, we establish regularity properties for any strong solution regardless of its size. (paper)

Glutamate Transporters in the Blood-Brain Barrier

DEFF Research Database (Denmark)

Helms, Hans Christian Cederberg; Nielsen, Carsten Uhd; Waagepetersen, Helle S

2017-01-01

concentration of L-glutamate causes excitotoxicity. A tight control of the brain interstitial fluid L-glutamate levels is therefore imperative, in order to maintain optimal neurotransmission and to avoid such excitotoxicity. The blood-brain barrier, i.e., the endothelial lining of the brain capillaries...... cells. The mechanisms underlying transendothelial L-glutamate transport are however still not well understood. The present chapter summarizes the current knowledge on blood-brain barrier L-glutamate transporters and the suggested pathways for the brain-to-blood L-glutamate efflux......., regulates the exchange of nutrients, gases, and metabolic waste products between plasma and brain interstitial fluid. It has been suggested that brain capillary endothelial cells could play an important role in L-glutamate homeostasis by mediating brain-to-blood L-glutamate efflux. Both in vitro and in vivo...

Black dimensional stones: Geology, technical properties and deposit characterization of the dolerites from Uruguay

Science.gov (United States)

Morales Demarco, M.; Oyhantçabal, P.; Stein, K.-J.; Siegesmund, S.

2012-04-01

Dimensional stones with a black color occupy a prominent place on the international market. Uruguayan dolerite dikes of andesitic and andesitic-basaltic composition are mined for commercial blocks of black dimensional stones. A total of 16 dikes of both compositions were studied and samples collected for geochemical and petrographical analysis. Color measurements were performed on different black dimensional stones in order to compare them with the Uruguayan dolerites. Samples of the two commercial varieties (Absolute Black and Moderate Black) were obtained for petrophysical analysis (e.g. density, porosity, uniaxial compressive strength, tensile strength, etc.). Detailed structural analyses were performed in several quarries. Geochemistry and petrography determines the intensity of the black color. When compared with commercial samples from China, Brazil, India and South Africa, among others, the Uruguayan dolerite Absolute Black is the darkest black dimensional stone analyzed. In addition, the petrophysical properties of the Uruguayan dolerites make them one of the highest quality black dimensional stones. Structural analyses show that five joint sets have been recognized: two sub-vertical joints, one horizontal and two diagonal. These joint sets are one of the most important factors that control the deposits, since they control the block size distribution and the amount of waste material.

Radiosurgery for brain metastases: is whole brain radiation therapy necessary?

International Nuclear Information System (INIS)

Forstner, Julie M.; Sneed, Penny K.; Lamborn, Kathleen R.; Shu, H.-K.G.; McDermott, Michael W.; Park, Elaine; Ho, Maria; Chang, Susan; Gutin, Philip H.; Phillips, Theodore L.; Wara, William M.; Larson, David A.

1996-01-01

Purpose: Because whole brain radiotherapy (WBRT) carries a significant risk of dementia in long-term survivors, it is desirable to determine if some patients with brain metastases may be managed with radiosurgery (RS) alone, reserving WBRT for salvage therapy as needed. To begin to approach this problem, we retrospectively reviewed freedom from brain failure/progression (Brain FFP) and survival of patients with newly-diagnosed solitary or multiple brain metastases treated with Gamma Knife RS ± WBRT. Materials and Methods: All patients treated at our institution with Gamma Knife RS for newly-diagnosed solitary or multiple (2-8) brain metastases from September 1991 through December 1995 were reviewed. Whether or not WBRT was given depended on physician preference and referral patterns. Brain FFP was measured from the date of RS until development of a new brain metastasis or progression of a treated metastasis, with censoring at the time of the last imaging study. Survival was measured from the date of RS until death or last clinical follow-up. Actuarial curves were estimated using the Kaplan-Meier method and compared with the log rank test. Multivariate analyses to adjust for known prognostic variables (age, KPS, history of extracranial metastases, and total target volume) were performed using the Cox proportional hazards model. Results: From September 1991-December 1995, 90 patients with newly-diagnosed brain metastases underwent RS. Three patients treated palliatively to a small component of their intracranial disease were excluded, leaving 54 treated with RS alone and 33 treated with RS + WBRT. Age ranged from 31-83 years (median, 59 years), KPS from 60-100 (median, 90), and total target volume from 0.15-26.1 cm 3 (median, 5.5 cm 3 ). Fifty patients had a history of extracranial metastases. Results are shown below. In the RS alone group, (22(54)) patients (41%) had a brain failure and (20(54)) (37%) died without evidence of brain failure. In the RS + WBRT group

Platelet-rich fibrin prepared from stored whole-blood samples.

Science.gov (United States)

Isobe, Kazushige; Suzuki, Masashi; Watanabe, Taisuke; Kitamura, Yutaka; Suzuki, Taiji; Kawabata, Hideo; Nakamura, Masayuki; Okudera, Toshimitsu; Okudera, Hajime; Uematsu, Kohya; Nakata, Koh; Tanaka, Takaaki; Kawase, Tomoyuki

2017-12-01

In regenerative therapy, self-clotted platelet concentrates, such as platelet-rich fibrin (PRF), are generally prepared on-site and are immediately used for treatment. If blood samples or prepared clots can be preserved for several days, their clinical applicability will expand. Here, we prepared PRF from stored whole-blood samples and examined their characteristics. Blood samples were collected from non-smoking, healthy male donors (aged 27-67 years, N = 6), and PRF clots were prepared immediately or after storage for 1-2 days. Fibrin fiber was examined by scanning electron microscopy. Bioactivity was evaluated by means of a bioassay system involving human periosteal cells, whereas PDGF-BB concentrations were determined by an enzyme-linked immunosorbent assay. Addition of optimal amounts of a 10% CaCl 2 solution restored the coagulative ability of whole-blood samples that contained an anticoagulant (acid citrate dextrose) and were stored for up to 2 days at ambient temperature. In PRF clots prepared from the stored whole-blood samples, the thickness and cross-links of fibrin fibers were almost identical to those of freshly prepared PRF clots. PDGF-BB concentrations in the PRF extract were significantly lower in stored whole-blood samples than in fresh samples; however, both extracts had similar stimulatory effects on periosteal-cell proliferation. Quality of PRF clots prepared from stored whole-blood samples is not reduced significantly and can be ensured for use in regenerative therapy. Therefore, the proposed method enables a more flexible treatment schedule and choice of a more suitable platelet concentrate immediately before treatment, not after blood collection.

Comparison of stereotactic radiosurgery (SRS) alone and whole brain radiotherapy (WBRT) plus a stereotactic boost (WBRT + SRS) for one to three brain metastases

Energy Technology Data Exchange (ETDEWEB)

Rades, Dirk [University Hospital Schleswig-Holstein, Luebeck (Germany). Department of Radiation Oncology]|[University Medical Center, Hamburg (Germany). Department of Radiation Oncology; Kueter, Jan-Dirk; Dunst, Juergen [University Hospital Schleswig-Holstein, Luebeck (Germany). Department of Radiation Oncology; Hornung, Dagmar [University Medical Center, Hamburg (Germany). Department of Radiation Oncology; Veninga, Theo; Hanssens, Patrick [Dr. Bernard Verbeeten Institute, Tilburg (Netherlands). Department of Radiation Oncology; Schild, Steven E. [Mayo Clinic Scottsdale, AZ (United States). Department of Radiation Oncology

2008-12-15

The best available treatment of patients with one to three brain metastases is still unclear. This study compared the results of stereotactic radiosurgery (SRS) alone and whole brain radiotherapy (WBRT) plus SRS (WBRT + SRS). Survival (OS), intracerebral control (IC), and local control of treated metastases (LC) were retrospectively analyzed in 144 patients receiving SRS alone (n = 93) or WBRT + SRS (n = 51). Eight additional potential prognostic factors were evaluated: age, gender, Eastern Cooperative Oncology Group performance score (ECOG-PS), tumor type, number of brain metastases, extracerebral metastases, recursive partitioning analysis (RPA) class, and interval from tumor diagnosis to irradiation. Subgroup analyses were performed for RPA class I and II patients. 1-year-OS was 53% after SRS and 56% after WBRT + SRS (p = 0.24). 1-year-IC rates were 51% and 66% (p = 0.015), respectively. 1-year-LC rates were 66% and 87% (p = 0.003), respectively. On multivariate analyses, OS was associated with age (p = 0.004), ECOG-PS (p = 0.005), extracerebral metastases (p < 0.001), RPA class (p < 0.001), and interval from tumor diagnosis to irradiation (p < 0.001). IC was associated with interval from tumor diagnosis to irradiation (p = 0.004) and almost with treatment (p = 0.09), and LC with treatment (p = 0.026) and almost with interval (p = 0.08). The results of the subgroup analyses were similar to those of the entire cohort. The increase in IC was stronger in RPA class I patients. WBRT + SRS resulted in better IC and LC but not better OS than SRS alone. Because also IC and LC are important end-points, additional WBRT appears justified in patients with one to three brain metastases, in particular in RPA class I patients. (orig.)

Comparison of stereotactic radiosurgery (SRS) alone and whole brain radiotherapy (WBRT) plus a stereotactic boost (WBRT + SRS) for one to three brain metastases

International Nuclear Information System (INIS)

Rades, Dirk; University Medical Center, Hamburg; Kueter, Jan-Dirk; Dunst, Juergen; Hornung, Dagmar; Veninga, Theo; Hanssens, Patrick; Schild, Steven E.

2008-01-01

The best available treatment of patients with one to three brain metastases is still unclear. This study compared the results of stereotactic radiosurgery (SRS) alone and whole brain radiotherapy (WBRT) plus SRS (WBRT + SRS). Survival (OS), intracerebral control (IC), and local control of treated metastases (LC) were retrospectively analyzed in 144 patients receiving SRS alone (n = 93) or WBRT + SRS (n = 51). Eight additional potential prognostic factors were evaluated: age, gender, Eastern Cooperative Oncology Group performance score (ECOG-PS), tumor type, number of brain metastases, extracerebral metastases, recursive partitioning analysis (RPA) class, and interval from tumor diagnosis to irradiation. Subgroup analyses were performed for RPA class I and II patients. 1-year-OS was 53% after SRS and 56% after WBRT + SRS (p = 0.24). 1-year-IC rates were 51% and 66% (p = 0.015), respectively. 1-year-LC rates were 66% and 87% (p = 0.003), respectively. On multivariate analyses, OS was associated with age (p = 0.004), ECOG-PS (p = 0.005), extracerebral metastases (p < 0.001), RPA class (p < 0.001), and interval from tumor diagnosis to irradiation (p < 0.001). IC was associated with interval from tumor diagnosis to irradiation (p = 0.004) and almost with treatment (p = 0.09), and LC with treatment (p = 0.026) and almost with interval (p = 0.08). The results of the subgroup analyses were similar to those of the entire cohort. The increase in IC was stronger in RPA class I patients. WBRT + SRS resulted in better IC and LC but not better OS than SRS alone. Because also IC and LC are important end-points, additional WBRT appears justified in patients with one to three brain metastases, in particular in RPA class I patients. (orig.)

Three-dimensional anisotropy contrast (3DAC) magnetic resonance imaging of the human brain. Application to assess Wallerian degeneration

Energy Technology Data Exchange (ETDEWEB)

Igarashi, Hironaka; Katayama, Yasuo; Tsuganezawa, Toshikazu; Yamamuro, Manabu; Terashi, Akiro; Owan, Chojin [Nippon Medical School, Tokyo (Japan)

1998-08-01

Three-dimensional anisotropy contrast (3DAC) magnetic resonance imaging is a new algorithm for the treatment of apparent diffusion tensor using the three primary colors. To determine if 3DAC has a clinical application for human brain, six normal volunteers and twenty patients with supratentorial cerebrovascular accidents were examined using clinical magnetic resonance imaging (MRI), and the changes in the 3DAC images associated with Wallerian degeneration of the pyramidal tract were evaluated. The 3DAC images exhibited impressive anatomical resolution. In all chronic stage patients with hemiparesis, the colors in the pyramidal tract were faded. Patients examined during the acute stage who later recovered from hemiparesis had no visible changes of the 3DAC image, whereas patients who recovered poorly showed distinct color fading in the pyramidal tract within 14 days following stroke. In conclusion, very fine anatomical structures are visible on 3DAC images, and it can be used as a diagnostic tool for the human brain. (author)

Three-dimensional anisotropy contrast (3DAC) magnetic resonance imaging of the human brain. Application to assess Wallerian degeneration

International Nuclear Information System (INIS)

Igarashi, Hironaka; Katayama, Yasuo; Tsuganezawa, Toshikazu; Yamamuro, Manabu; Terashi, Akiro; Owan, Chojin

1998-01-01

Three-dimensional anisotropy contrast (3DAC) magnetic resonance imaging is a new algorithm for the treatment of apparent diffusion tensor using the three primary colors. To determine if 3DAC has a clinical application for human brain, six normal volunteers and twenty patients with supratentorial cerebrovascular accidents were examined using clinical magnetic resonance imaging (MRI), and the changes in the 3DAC images associated with Wallerian degeneration of the pyramidal tract were evaluated. The 3DAC images exhibited impressive anatomical resolution. In all chronic stage patients with hemiparesis, the colors in the pyramidal tract were faded. Patients examined during the acute stage who later recovered from hemiparesis had no visible changes of the 3DAC image, whereas patients who recovered poorly showed distinct color fading in the pyramidal tract within 14 days following stroke. In conclusion, very fine anatomical structures are visible on 3DAC images, and it can be used as a diagnostic tool for the human brain. (author)

Five-dimensional Myers-Perry black holes cannot be overspun in gedanken experiments

Science.gov (United States)

An, Jincheng; Shan, Jieru; Zhang, Hongbao; Zhao, Suting

2018-05-01

We apply the new version of a gedanken experiment designed recently by Sorce and Wald to overspin the five-dimensional Myers-Perry black holes. As a result, the extremal black holes cannot be overspun at the linear order. On the other hand, although the nearly extremal black holes could be overspun at the linear order, this process is shown to be prohibited by the quadratic order correction. Thus, no violation of the weak cosmic censorship conjecture occurs around the five-dimensional Myers-Perry black holes.

The Blood-Brain Barrier: An Engineering Perspective

Directory of Open Access Journals (Sweden)

Andrew eWong

2013-08-01

Full Text Available It has been more than 100 years since Paul Ehrlich reported that various water-soluble dyes injected into the circulation did not enter the brain. Since Ehrlich’s first experiments, only a small number of molecules, such as alcohol and caffeine have been found to cross the blood-brain barrier, and it remains the major roadblock to treatment of many central nervous system diseases. At the same time, many central nervous system diseases are associated with disruption of the blood-brain barrier that can lead to changes in permeability, modulation of immune cell transport, and trafficking of pathogens into the brain. Therefore advances in our understanding of the structure and function of the blood-brain barrier are key to advances in treatment of a wide range of central nervous system diseases. Over the past 10 years it has become recognized that the blood-brain barrier is a complex dynamic system that involves biomechanical and biochemical signaling between the vascular system and the brain. Here we reconstruct the structure, function, and transport properties of the blood-brain barrier from an engineering perspective. New insight into the physics of the blood-brain barrier could ultimately lead to clinical advances in the treatment of central nervous system diseases.

Rapid whole-brain resting-state fMRI at 3 T: Efficiency-optimized three-dimensional EPI versus repetition time-matched simultaneous-multi-slice EPI.

Science.gov (United States)

Stirnberg, Rüdiger; Huijbers, Willem; Brenner, Daniel; Poser, Benedikt A; Breteler, Monique; Stöcker, Tony

2017-12-01

State-of-the-art simultaneous-multi-slice (SMS-)EPI and 3D-EPI share several properties that benefit functional MRI acquisition. Both sequences employ equivalent parallel imaging undersampling with controlled aliasing to achieve high temporal sampling rates. As a volumetric imaging sequence, 3D-EPI offers additional means of acceleration complementary to 2D-CAIPIRINHA sampling, such as fast water excitation and elliptical sampling. We performed an application-oriented comparison between a tailored, six-fold CAIPIRINHA-accelerated 3D-EPI protocol at 530 ms temporal and 2.4 mm isotropic spatial resolution and an SMS-EPI protocol with identical spatial and temporal resolution for whole-brain resting-state fMRI at 3 T. The latter required eight-fold slice acceleration to compensate for the lack of elliptical sampling and fast water excitation. Both sequences used vendor-supplied on-line image reconstruction. We acquired test/retest resting-state fMRI scans in ten volunteers, with simultaneous acquisition of cardiac and respiration data, subsequently used for optional physiological noise removal (nuisance regression). We found that the 3D-EPI protocol has significantly increased temporal signal-to-noise ratio throughout the brain as compared to the SMS-EPI protocol, especially when employing motion and nuisance regression. Both sequence types reliably identified known functional networks with stronger functional connectivity values for the 3D-EPI protocol. We conclude that the more time-efficient 3D-EPI primarily benefits from reduced parallel imaging noise due to a higher, actual k-space sampling density compared to SMS-EPI. The resultant BOLD sensitivity increase makes 3D-EPI a valuable alternative to SMS-EPI for whole-brain fMRI at 3 T, with voxel sizes well below 3 mm isotropic and sampling rates high enough to separate dominant cardiac signals from BOLD signals in the frequency domain. Copyright © 2017 Elsevier Inc. All rights reserved.

Preparing Platelet-Rich Plasma with Whole Blood Harvested Intraoperatively During Spinal Fusion.

Science.gov (United States)

Shen, Bin; Zhang, Zheng; Zhou, Ning-Feng; Huang, Yu-Feng; Bao, Yu-Jie; Wu, De-Sheng; Zhang, Ya-Dong

2017-07-22

BACKGROUND Platelet-rich plasma (PRP) has gained growing popularity in use in spinal fusion procedures in the last decade. Substantial intraoperative blood loss is frequently accompanied with spinal fusion, and it is unknown whether blood harvested intraoperatively qualifies for PRP preparation. MATERIAL AND METHODS Whole blood was harvested intraoperatively and venous blood was collected by venipuncture. Then, we investigated the platelet concentrations in whole blood and PRP, the concentration of growth factors in PRP, and the effects of PRP on the proliferation and viability of human bone marrow-derived mesenchymal stem cells (HBMSCs). RESULTS Our results revealed that intraoperatively harvested whole blood and whole blood collected by venipuncture were similar in platelet concentration. In addition, PRP formulations prepared from both kinds of whole blood were similar in concentration of platelet and growth factors. Additional analysis showed that the similar concentrations of growth factors resulted from the similar platelet concentrations of whole blood and PRP between the two groups. Moreover, these two kinds of PRP formulations had similar effects on promoting cell proliferation and enhancing cell viability. CONCLUSIONS Therefore, intraoperatively harvested whole blood may be a potential option for preparing PRP spinal fusion.

In vitro blood-brain barrier models: current and perspective technologies.

Science.gov (United States)

Naik, Pooja; Cucullo, Luca

2012-04-01

Even in the 21st century, studies aimed at characterizing the pathological paradigms associated with the development and progression of central nervous system diseases are primarily performed in laboratory animals. However, limited translational significance, high cost, and labor to develop the appropriate model (e.g., transgenic or inbred strains) have favored parallel in vitro approaches. In vitro models are of particular interest for cerebrovascular studies of the blood-brain barrier (BBB), which plays a critical role in maintaining the brain homeostasis and neuronal functions. Because the BBB dynamically responds to many events associated with rheological and systemic impairments (e.g., hypoperfusion), including the exposure of potentially harmful xenobiotics, the development of more sophisticated artificial systems capable of replicating the vascular properties of the brain microcapillaries are becoming a major focus in basic, translational, and pharmaceutical research. In vitro BBB models are valuable and easy to use supporting tools that can precede and complement animal and human studies. In this article, we provide a detailed review and analysis of currently available in vitro BBB models ranging from static culture systems to the most advanced flow-based and three-dimensional coculture apparatus. We also discuss recent and perspective developments in this ever expanding research field. Copyright © 2011 Wiley Periodicals, Inc.

MRI assessment of whole-brain structural changes in aging.

Science.gov (United States)

Guo, Hui; Siu, William; D'Arcy, Ryan Cn; Black, Sandra E; Grajauskas, Lukas A; Singh, Sonia; Zhang, Yunting; Rockwood, Kenneth; Song, Xiaowei

2017-01-01

One of the central features of brain aging is the accumulation of multiple age-related structural changes, which occur heterogeneously in individuals and can have immediate or potential clinical consequences. Each of these deficits can coexist and interact, producing both independent and additive impacts on brain health. Many of the changes can be visualized using MRI. To collectively assess whole-brain structural changes, the MRI-based Brain Atrophy and Lesion Index (BALI) has been developed. In this study, we validate this whole-brain health assessment approach using several clinical MRI examinations. Data came from three independent studies: the Alzheimer's Disease Neuroimaging Initiative Phase II (n=950; women =47.9%; age =72.7±7.4 years); the National Alzheimer's Coordinating Center (n=722; women =55.1%; age =72.7±9.9 years); and the Tianjin Medical University General Hospital Research database on older adults (n=170; women =60.0%; age =62.9±9.3 years). The 3.0-Tesla MRI scans were evaluated using the BALI rating scheme on the basis of T1-weighted (T1WI), T2-weighted (T2WI), T2-weighted fluid-attenuated inversion recovery (T2-FLAIR), and T2*-weighted gradient-recalled echo (T2*GRE) images. Atrophy and lesion changes were commonly seen in each MRI test. The BALI scores based on different sequences were highly correlated (Spearman r 2 >0.69; P age ( r 2 >0.29; P 26.48, P aging and dementia-related decline of structural brain health. Inclusion of additional MRI tests increased lesion differentiation. Further research is to integrate MRI tests for a clinical tool to aid the diagnosis and intervention of brain aging.

PET with three-dimensional data sampling and its clinical applications

International Nuclear Information System (INIS)

Itoh, M.; Tashiro, M.; Ishii, K.; Kubota, K.; Fujimoto, T.

2000-01-01

3D-PET (Positron Emission Tomography with tree-dimensional data acquisition capacity) is a powerful tool for whole-body imaging of metabolism in human in vivo. Thanks its high sensitivity, high-quality images are obtained with reduced radiation exposure to patients. In order to facilitate the use of 3D-PET in clinical practice, our PET system is connected to a super-computer (SX4, NEC, Japan) for data processing and image-reconstruction using 3D-reprojection-backprojection algorithm. The impact of this imaging system emerged immediately in ontological applications. Localization and assessment of spread of malignant tumors can be made by injection of appropriate radiotracers, 18 F-fluoro-deoxy-glucose usually, and scanning whole body with sequential patient coach movement. We have extended this technique to the analysis of brain of patients having cancer, because psychological and psychiatrical abnormalities have been reported frequent in these patients. The results clearly showed abnormality in brain glucose metabolism in cancer patients, the metabolic reduction was noted in lower medial frontal cortex, hippocampus, amygdaloid cortex, and cingulate cortex. The reductions were significantly correlated with scores of depressiveness. 3D PET is a currently ideal tool to evacuate metabolic abnormalities such as cancer in the whole-body. (author)

Habitat preferences among three top predators inhabiting a degraded ecosystem, the Black Sea

Directory of Open Access Journals (Sweden)

Alicia Sánchez-Cabanes

2017-06-01

Full Text Available This study investigated whether there is evidence of widespread niche partitioning based on environmental factors in the Black Sea and tested the hypothesis that physiographic factors may be employed as predictors. It addresses poorly researched areas with good habitat potential for the only three cetacean subspecies living in this area: the Black Sea short-beaked common dolphin (Delphinus delphis spp. ponticus, the Black Sea bottlenose dolphin (Tursiops truncatus spp. ponticus and the Black Sea harbour porpoise (Phocoena phocoena spp. relicta. Generalized additive models (GAMs were used to analyse data collected from multiple sources. In total, 745 sightings of the three species between 1998 and 2010 throughout the Black Sea were included. The analysis found depth and sea surface temperature to be the most important variables for separating the occurrence of the three species. Common dolphins occurred mainly in deep waters and in areas where the sea surface temperature was low, bottlenose dolphins were distributed primarily in shallower and warmer waters than common dolphins, and harbour porpoises were distributed in shallower waters with lower sea surface temperature than bottlenose dolphins. This study suggests strong niche segregation among the three cetacean species. The study is also the first contribution to the basic information of cetacean species distribution and habitat preferences in the Black Sea as a whole. Knowledge of the distribution of the three dolphin species in the study area is essential to establish conservation measures for these populations.

Quality of brain perfusion single-photon emission tomography images: multicentre evaluation using an anatomically accurate three-dimensional phantom

International Nuclear Information System (INIS)

Heikkinen, J.; Kuikka, J.T.; Ahonen, A.; Rautio, P.

1998-01-01

The aim of the study was to evaluate the quality of routine brain perfusion single-photon emission tomography (SPET) images in Finnish nuclear medicine laboratories. Twelve laboratories participated in the study. A three-dimensional high resolution brain phantom (Data Spectrum's 3D Hoffman Brain Phantom) was filled with a well-mixed solution of technetium-99m (110 MBq), water and detergent. Acquisition, reconstruction and printing were performed according to the clinical routine in each centre. Three nuclear medicine specialists blindly evaluated all image sets. The results were ranked from 1 to 5 (poor quality-high quality). Also a SPET performance phantom (Nuclear Associates' PET/SPECT Performance Phantom PS 101) was filled with the same radioactivity concentration as the brain phantom. The parameters for the acquisition, the reconstruction and the printing were exactly the same as with the brain phantom. The number of detected ''hot'' (from 0 to 8) and ''cold'' lesions (from 0 to 7) was visually evaluated from hard copies. Resolution and contrast were quantified from digital images. Average score for brain phantom images was 2.7±0.8 (range 1.5-4.5). The average diameter of the ''hot'' cylinders detected was 16 mm (range 9.2-20.0 mm) and that of the ''cold'' cylinders detected, 11 mm (5.9-14.3 mm) according to visual evaluation. Quantification of digital images showed that the hard copy was one reason for low-quality images. The quality of the hard copies was good only in four laboratories and was amazingly low in the others when comparing it with the actual structure of the brain phantom. The described quantification method is suitable for optimizing resolution and contrast detectability of hard copies. This study revealed the urgent need for external quality assurance of clinical brain perfusion SPET images. (orig.)

Effect of solvent/detergent-treated pooled plasma on fibrinolysis in reconstituted whole blood.

Science.gov (United States)

Saadah, Nicholas H; van der Meer, Pieter F; Brinkman, Herm Jan M; de Korte, Dirk; Bontekoe, Ido J; Korsten, Herbert H; Middelburg, Rutger A; van der Bom, Johanna G; Schipperus, Martin R

2017-10-01

Hyperfibrinolysis has been observed in patients heavily transfused with solvent/detergent-treated pooled plasma (S/D plasma). We compared coagulation and fibrinolytic variables in blood containing S/D plasma with blood containing fresh-frozen plasma (FFP), with and without α2-antiplasmin or tranexamic acid (TXA) supplementation. Whole blood samples were reconstituted from red blood cells, platelet (PLT) concentrates, and varying mixtures of FFP and S/D plasma. Hematocrit and PLT count of reconstituted whole blood samples were varied. For a subset of runs, α2-antiplasmin or TXA was added to S/D plasma whole blood samples. Thromboelastography (TEG) analysis was performed to assess 50% clot lysis time (CLT 50% ), maximum amplitude (MA), and initial clotting time (R-time). The change in CLT 50% of whole blood as the plasma compartment transitions from FFP to S/D plasma was -52% (95% confidence interval [CI], -60% to -45%; p plasma in whole blood. α2-Antiplasmin and TXA restored clot lysis time in S/D plasma whole blood. Whole blood with S/D plasma has shorter clot lysis times in vitro compared to whole blood with FFP. α2-Antiplasmin and TXA restore clot lysis time of S/D plasma whole blood to that of FFP whole blood. Clinicians should be aware of the decreased clot lysis time associated with S/D plasma transfusion. © 2017 AABB.

Evaluating Changes to Blood-Brain Barrier Integrity in Brain Metastasis over Time and after Radiation Treatment

Directory of Open Access Journals (Sweden)

Donna H. Murrell

2016-06-01

Full Text Available INTRODUCTION: The incidence of brain metastasis due to breast cancer is increasing, and prognosis is poor. Treatment is challenging because the blood-brain barrier (BBB limits efficacy of systemic therapies. In this work, we develop a clinically relevant whole brain radiotherapy (WBRT plan to investigate the impact of radiation on brain metastasis development and BBB permeability in a murine model. We hypothesize that radiotherapy will decrease tumor burden and increase tumor permeability, which could offer a mechanism to increase drug uptake in brain metastases. METHODS: Contrast-enhanced magnetic resonance imaging (MRI and high-resolution anatomical MRI were used to evaluate BBB integrity associated with brain metastases due to breast cancer in the MDA-MB-231-BR-HER2 model during their natural development. Novel image-guided microirradiation technology was employed to develop WBRT treatment plans and to investigate if this altered brain metastatic growth or permeability. Histology and immunohistochemistry were performed on whole brain slices corresponding with MRI to validate and further investigate radiological findings. RESULTS: Herein, we show successful implementation of microirradiation technology that can deliver WBRT to small animals. We further report that WBRT following diagnosis of brain metastasis can mitigate, but not eliminate, tumor growth in the MDA-MB-231-BR-HER2 model. Moreover, radiotherapy did not impact BBB permeability associated with metastases. CONCLUSIONS: Clinically relevant WBRT is not curative when delivered after MRI-detectable tumors have developed in this model. A dose of 20 Gy in 2 fractions was not sufficient to increase tumor permeability such that it could be used as a method to increase systemic drug uptake in brain metastasis.

New approach to 'top-and-bottom' whole blood separation using the multiunit TACSI WB system: quality of blood components.

Science.gov (United States)

Lotens, A; Najdovski, T; Cellier, N; Ernotte, B; Lambermont, M; Rapaille, A

2014-10-01

TACSI whole blood system is designed to combine primary and secondary processing of six whole blood bags into plasma units, buffy coat and red blood cell concentrates. The aim of this study was to investigate the specifications and in vitro storage parameters of blood components compared with standard centrifugation and separation processing. Whole blood bags, collected in CRC kits, were treated on a TACSI whole blood system. They were compared with whole blood bags collected in Composelect kits. In addition to routine quality control analyses, conservation studies were performed on red blood cell concentrates for 42 days and on plasma for 6 months. Platelets pools with five buffy coats were also created, and cellular contamination was evaluated. Red blood cell concentrates produced from TACSI whole blood met European quality requirements. For white blood cell count, one individual result exceeded 1 × 10(6) cells/unit. All plasma units fell within specifications for residual cellular contamination and storage parameters. The performances of the TACSI whole blood system allow for the preparation of low volume buffy coats with a recovery of 90% of whole blood platelets. Haemoglobin losses in TACSI BC are smaller, but this did not result in higher haemoglobin content of red cells. These BC are suitable for the production of platelet concentrates. From these in vitro data, red blood cell concentrates produced using TACSI whole blood are suitable for clinical use with a quality at least equivalent to the control group. © 2014 International Society of Blood Transfusion.

Inertia-dependent dynamics of three-dimensional vesicles and red blood cells in shear flow.

Science.gov (United States)

Luo, Zheng Yuan; Wang, Shu Qi; He, Long; Xu, Feng; Bai, Bo Feng

2013-10-28

A three-dimensional (3D) simulation study of the effect of inertia on the dynamics of vesicles and red blood cells (RBCs) has not been reported. Here, we developed a 3D model based on the front tracking method to investigate how inertia affects the dynamics of spherical/non-spherical vesicles and biconcave-shaped RBCs with the Reynolds number ranging from 0.1 to 10. The results showed that inertia induced non-spherical vesicles transitioned from tumbling to swinging, which was not observed in previous 2D models. The critical viscosity ratio of inner/outer fluids for the tumbling–swinging transition remarkably increased with an increasing Reynolds number. The deformation of vesicles was greatly enhanced by inertia, and the frequency of tumbling and tank-treading was significantly decreased by inertia. We also found that RBCs can transit from tumbling to steady tank-treading through the swinging regime when the Reynolds number increased from 0.1 to 10. These results indicate that inertia needs to be considered at moderate Reynolds number (Re ~ 1) in the study of blood flow in the human body and the flow of deformable particle suspension in inertial microfluidic devices. The developed 3D model provided new insights into the dynamics of RBCs under shear flow, thus holding great potential to better understand blood flow behaviors under normal/disease conditions.

A clearer view of the insect brain – combining bleaching with standard whole-mount immunocytochemistry allows confocal imaging of pigment-covered brain areas for 3D reconstruction.

Directory of Open Access Journals (Sweden)

Anna Lisa Stöckl

2015-09-01

Full Text Available In the study of insect neuroanatomy, three-dimensional reconstructions of neurons and neuropils have become a standard technique. As images have to be obtained from whole-mount brain preparations, pigmentation on the brain surface poses a serious challenge to imaging. In insects, this is a major problematic in the first visual neuropil of the optic lobe, the lamina, which is obstructed by the pigment of the retina as well as by the pigmented fenestration layer. This has prevented inclusion of this major processing center of the insect visual system into most neuroanatomical brain atlases and hinders imaging of neurons within the lamina by confocal microscopy. It has recently been shown that hydrogen peroxide bleaching is compatible with immunohistochemical labeling in insect brains, and we therefore developed a simple technique for removal of pigments on the surface of insect brains by chemical bleaching. We show that our technique enables imaging of the pigment-obstructed regions of insect brains when combined with standard protocols for both anti-synapsin-labeled as well as neurobiotin-injected samples. This method can be combined with different fixation procedures, as well as different fluorophore excitation wavelengths without negative effects on staining quality. It can therefore serve as an effective addition to most standard histology protocols used in insect neuroanatomy.

Three-dimensional dilatonic gravity's rainbow: Exact solutions

International Nuclear Information System (INIS)

Hossein Hendi, Seyed; Eslam Panah, Behzad; Panahiyan, Shahram

2016-01-01

Deep relations of dark energy scenario and string theory results into dilaton gravity, on the one hand, and the connection between quantum gravity and gravity's rainbow, on the other hand, motivate us to consider three-dimensional dilatonic black hole solutions in gravity's rainbow. We obtain two classes of the solutions, which are polynomial and logarithmic forms. We also calculate conserved and thermodynamic quantities, and examine the first law of thermodynamics for both classes. In addition, we study thermal stability and show that one of the classes is thermally stable while the other one is unstable.

Molecular biology of the blood-brain and the blood-cerebrospinal fluid barriers: similarities and differences

Directory of Open Access Journals (Sweden)

Redzic Zoran

2011-01-01

Full Text Available Abstract Efficient processing of information by the central nervous system (CNS represents an important evolutionary advantage. Thus, homeostatic mechanisms have developed that provide appropriate circumstances for neuronal signaling, including a highly controlled and stable microenvironment. To provide such a milieu for neurons, extracellular fluids of the CNS are separated from the changeable environment of blood at three major interfaces: at the brain capillaries by the blood-brain barrier (BBB, which is localized at the level of the endothelial cells and separates brain interstitial fluid (ISF from blood; at the epithelial layer of four choroid plexuses, the blood-cerebrospinal fluid (CSF barrier (BCSFB, which separates CSF from the CP ISF, and at the arachnoid barrier. The two barriers that represent the largest interface between blood and brain extracellular fluids, the BBB and the BCSFB, prevent the free paracellular diffusion of polar molecules by complex morphological features, including tight junctions (TJs that interconnect the endothelial and epithelial cells, respectively. The first part of this review focuses on the molecular biology of TJs and adherens junctions in the brain capillary endothelial cells and in the CP epithelial cells. However, normal function of the CNS depends on a constant supply of essential molecules, like glucose and amino acids from the blood, exchange of electrolytes between brain extracellular fluids and blood, as well as on efficient removal of metabolic waste products and excess neurotransmitters from the brain ISF. Therefore, a number of specific transport proteins are expressed in brain capillary endothelial cells and CP epithelial cells that provide transport of nutrients and ions into the CNS and removal of waste products and ions from the CSF. The second part of this review concentrates on the molecular biology of various solute carrier (SLC transport proteins at those two barriers and underlines

First law of black ring thermodynamics in higher dimensional Chern-Simons gravity

International Nuclear Information System (INIS)

Rogatko, Marek

2007-01-01

The physical process version and the equilibrium state version of the first law of black ring thermodynamics in n-dimensional Einstein gravity with Chern-Simons term were derived. This theory constitutes the simplest generalization of the five-dimensional one admitting a stationary black ring solution. The equilibrium state version of the first law of black ring mechanics was achieved by choosing any cross section of the event horizon to the future of the bifurcation surface

Bulk emission by higher-dimensional black holes: almost perfect blackbody radiation

International Nuclear Information System (INIS)

Hod, Shahar

2011-01-01

We study the Hawking radiation emitted into the bulk by (D + 1)-dimensional Schwarzschild black holes. It is well known that the black-hole spectrum departs from exact blackbody form due to the frequency dependence of the 'greybody' factors. For intermediate values of D (3 ≤ D ∼ > 1, the typical wavelengths in the black-hole spectrum are much shorter than the size of the black hole. In this regime, the greybody factors are well described by the geometric-optics approximation according to which they are almost frequency independent. Following this observation, we argue that for higher-dimensional black holes with D >> 1, the total power emitted into the bulk should be well approximated by the analytical formula for perfect blackbody radiation. We test the validity of this analytical prediction with numerical computations.

Parameterization of the Age-Dependent Whole Brain Apparent Diffusion Coefficient Histogram

Science.gov (United States)

Batra, Marion; Nägele, Thomas

2015-01-01

Purpose. The distribution of apparent diffusion coefficient (ADC) values in the brain can be used to characterize age effects and pathological changes of the brain tissue. The aim of this study was the parameterization of the whole brain ADC histogram by an advanced model with influence of age considered. Methods. Whole brain ADC histograms were calculated for all data and for seven age groups between 10 and 80 years. Modeling of the histograms was performed for two parts of the histogram separately: the brain tissue part was modeled by two Gaussian curves, while the remaining part was fitted by the sum of a Gaussian curve, a biexponential decay, and a straight line. Results. A consistent fitting of the histograms of all age groups was possible with the proposed model. Conclusions. This study confirms the strong dependence of the whole brain ADC histograms on the age of the examined subjects. The proposed model can be used to characterize changes of the whole brain ADC histogram in certain diseases under consideration of age effects. PMID:26609526

Parameterization of the Age-Dependent Whole Brain Apparent Diffusion Coefficient Histogram

Directory of Open Access Journals (Sweden)

Uwe Klose

2015-01-01

Full Text Available Purpose. The distribution of apparent diffusion coefficient (ADC values in the brain can be used to characterize age effects and pathological changes of the brain tissue. The aim of this study was the parameterization of the whole brain ADC histogram by an advanced model with influence of age considered. Methods. Whole brain ADC histograms were calculated for all data and for seven age groups between 10 and 80 years. Modeling of the histograms was performed for two parts of the histogram separately: the brain tissue part was modeled by two Gaussian curves, while the remaining part was fitted by the sum of a Gaussian curve, a biexponential decay, and a straight line. Results. A consistent fitting of the histograms of all age groups was possible with the proposed model. Conclusions. This study confirms the strong dependence of the whole brain ADC histograms on the age of the examined subjects. The proposed model can be used to characterize changes of the whole brain ADC histogram in certain diseases under consideration of age effects.

Quantitative estimation of brain atrophy and function with PET and MRI two-dimensional projection images

International Nuclear Information System (INIS)

Saito, Reiko; Uemura, Koji; Uchiyama, Akihiko; Toyama, Hinako; Ishii, Kenji; Senda, Michio

2001-01-01

The purpose of this paper is to estimate the extent of atrophy and the decline in brain function objectively and quantitatively. Two-dimensional (2D) projection images of three-dimensional (3D) transaxial images of positron emission tomography (PET) and magnetic resonance imaging (MRI) were made by means of the Mollweide method which keeps the area of the brain surface. A correlation image was generated between 2D projection images of MRI and cerebral blood flow (CBF) or 18 F-fluorodeoxyglucose (FDG) PET images and the sulcus was extracted from the correlation image clustered by K-means method. Furthermore, the extent of atrophy was evaluated from the extracted sulcus on 2D-projection MRI and the cerebral cortical function such as blood flow or glucose metabolic rate was assessed in the cortex excluding sulcus on 2D-projection PET image, and then the relationship between the cerebral atrophy and function was evaluated. This method was applied to the two groups, the young and the aged normal subjects, and the relationship between the age and the rate of atrophy or the cerebral blood flow was investigated. This method was also applied to FDG-PET and MRI studies in the normal controls and in patients with corticobasal degeneration. The mean rate of atrophy in the aged group was found to be higher than that in the young. The mean value and the variance of the cerebral blood flow for the young are greater than those of the aged. The sulci were similarly extracted using either CBF or FDG PET images. The purposed method using 2-D projection images of MRI and PET is clinically useful for quantitative assessment of atrophic change and functional disorder of cerebral cortex. (author)

Zika Virus Infection and Prolonged Viremia in Whole-Blood Specimens.

Science.gov (United States)

Mansuy, Jean Michel; Mengelle, Catherine; Pasquier, Christophe; Chapuy-Regaud, Sabine; Delobel, Pierre; Martin-Blondel, Guillaume; Izopet, Jacques

2017-05-01

We tested whole-blood and plasma samples from immunocompetent patients who had had benign Zika virus infections and found that Zika virus RNA persisted in whole blood substantially longer than in plasma. This finding may have implications for diagnosis of acute symptomatic and asymptomatic infections and for testing of blood donations.

Stationary strings near a higher-dimensional rotating black hole

International Nuclear Information System (INIS)

Frolov, Valeri P.; Stevens, Kory A.

2004-01-01

We study stationary string configurations in a space-time of a higher-dimensional rotating black hole. We demonstrate that the Nambu-Goto equations for a stationary string in the 5D (five-dimensional) Myers-Perry metric allow a separation of variables. We present these equations in the first-order form and study their properties. We prove that the only stationary string configuration that crosses the infinite redshift surface and remains regular there is a principal Killing string. A worldsheet of such a string is generated by a principal null geodesic and a timelike at infinity Killing vector field. We obtain principal Killing string solutions in the Myers-Perry metrics with an arbitrary number of dimensions. It is shown that due to the interaction of a string with a rotating black hole, there is an angular momentum transfer from the black hole to the string. We calculate the rate of this transfer in a space-time with an arbitrary number of dimensions. This effect slows down the rotation of the black hole. We discuss possible final stationary configurations of a rotating black hole interacting with a string

Development of the blood-brain barrier: a historical point of view.

Science.gov (United States)

Ribatti, Domenico; Nico, Beatrice; Crivellato, Enrico; Artico, Marco

2006-01-01

Although there has been considerable controversy since the observation by Ehrlich more than 100 years ago that the brain did not take up dyes from the vascular system, the concept of an endothelial blood-brain barrier (BBB) was confirmed by the unequivocal demonstration that the passage of molecules from blood to brain and vice versa was prevented by endothelial tight junctions (TJs). There are three major functions implicated in the term "BBB": protection of the brain from the blood milieu, selective transport, and metabolism or modification of blood- or brain-borne substances. The BBB phenotype develops under the influence of associated brain cells, especially astrocytic glia, and consists of complex TJs and a number of specific transport and enzyme systems that regulate molecular traffic across the endothelial cells. The development of the BBB is a complex process that leads to endothelial cells with unique permeability characteristics due to high electrical resistance and the expression of specific transporters and metabolic pathways. This review article summarizes the historical background underlying our current knowledge of the cellular and molecular mechanisms involved in the development and maintenance of the BBB. (c) 2006 Wiley-Liss, Inc.

Stereotactic radiosurgery versus whole-brain radiotherapy after intracranial metastasis resection : A systematic review and meta-analysis

NARCIS (Netherlands)

Lamba, Nayan; Muskens, Ivo S; DiRisio, Aislyn C; Meijer, Louise; Briceno, Vanessa; Edrees, Heba; Aslam, Bilal; Minhas, Sadia; Verhoeff, Joost J.C.; Kleynen, Catharina E.; Smith, Timothy R; Mekary, Rania A; Broekman, Marike L.

2017-01-01

Background: In patients with one to three brain metastases who undergo resection, options for post-operative treatments include whole-brain radiotherapy (WBRT) or stereotactic radiosurgery (SRS) of the resection cavity. In this meta-analysis, we sought to compare the efficacy of each post-operative

Three-dimensional anisotropy contrast MRI and functional MRI of the human brain. Clinical application to assess pyramidal tract in patients with brain tumor and infarction

International Nuclear Information System (INIS)

Morikawa, Minoru; Kaminogo, Makio; Ishimaru, Hideki; Nakashima, Kazuaki; Kitagawa, Naoki; Ochi, Makoto; Hayashi, Kuniaki; Shibata, Shobu; Kabasawa, Hiroyuki

2001-01-01

We describe and evaluate the findings of three-dimensional anisotropy contrast MR axonography (3DAC MRX) and functional MRI (fMRI) in brain tumor and infarction. We obtained diffusion-weighted images (DWI) in 28 patients including 23 brain tumors and 15 acute infarctions located in or near pyramidal tract. Three anisotropic DWIs were transformed into graduations color-coded as red, green and blue, and then composed to form a combined color 3DAC MRX. We also performed functional MRI in 7 of the 28 patients and compared with cortical mapping of 3DAC MRX. 3DAC MRX with 23 brain tumors showed that the ipsilateral pyramidal tract was either discontinuous due to impaired anisotropy (n=8) or compressed due to mass effect (n=15). In 10 patients of acute infarction with motor impairment, pyramidal tract involvement was visually more conspicuous on 3DAC MRX compared to standard DWI. On functional MRI, hand motor activation was observed between blue vertical directional colors of pre- and post central gyrus. In conclusion, 3DAC MRX is a new noninvasive approach for visualization of the white matter neuronal tract and provides the information concerning pyramidal tract involvement. (author)

Thermodynamics of rotating black branes in (n+1)-dimensional Einstein-Born-Infeld gravity

International Nuclear Information System (INIS)

Dehghani, M. H.; Sedehi, H. R. Rastegar

2006-01-01

We construct a new class of charged rotating solutions of (n+1)-dimensional Einstein-Born-Infeld gravity with cylindrical or toroidal horizons in the presence of cosmological constant and investigate their properties. These solutions are asymptotically (anti)-de Sitter and reduce to the solutions of Einstein-Maxwell gravity as the Born-Infeld parameters goes to infinity. We find that these solutions can represent black branes, with inner and outer event horizons, an extreme black brane or a naked singularity provided the parameters of the solutions are chosen suitably. We compute temperature, mass, angular momentum, entropy, charge and electric potential of the black brane solutions. We obtain a Smarr-type formula and show that these quantities satisfy the first law of thermodynamics. We also perform a stability analysis by computing the heat capacity and the determinant of Hessian matrix of mass of the system with infinite boundary with respect to its thermodynamic variables in both the canonical and the grand-canonical ensembles, and show that the system is thermally stable in the whole phase space. Also, we find that there exists an unstable phase when the finite size effect is taken into account

Stereotactic irradiation without whole-brain irradiation for single brain metastasis

International Nuclear Information System (INIS)

Shirato, Hiroki; Takamura, Akio; Tomita, Masayoshi; Suzuki, Keishiro; Nishioka, Takashi; Isu, Toyohiko; Kato, Tsutomu; Sawamura, Yutaka; Miyamachi, Keikichi; Abe, Hiroshi; Miyasaka, Kazuo

1997-01-01

Purpose: The effectiveness of stereotactic irradiation (STI) alone without whole-brain irradiation (WBI) for a single metastatic brain tumor was analyzed retrospectively. Methods and Materials: Forty-four patients with this condition were treated using radiosurgery (RS) alone or fractionated stereotactic radiotherapy (FSR) without WBI. Results: The initial response rate was 92% and the overall local control rate was 84% (37 of 44 patients). A total of 39% (18 of 44) of patients experienced intracranial relapse outside the initial target area. Forty-eight percent (21 of 44) of patients required salvage treatment for intracranial relapse. All 7 patients who received WBI as salvage treatment required no further salvage treatment, but 5 of the 14 patients who received salvage STI without WBI required three to four treatments for brain metastasis. Late radiation damage was not seen with initial treatment but was observed with retreatment. The overall median survival time was 261 days, with a standard error of 64 days. Actuarial survival at 12 and 24 months was 34% and 9%, respectively. The actuarial survival rate was significantly affected by the existence of active extracranial disease (p = 0.041). Conclusion: The high response rate and short treatment period of STI alone are advantageous in the treatment of single brain metastasis in patients with active extracranial disease with WBI reserved for relapse. Because of the low complication rate, STI alone may be also useful in patients with good prognosis, without extracranial disease

Simulated blood transport of low density lipoproteins in a three-dimensional and permeable T-junction.

Science.gov (United States)

Shibeshi, Shewaferaw S; Everett, Joseph; Venable, Demetrius D; Collins, William E

2005-01-01

Previous studies indicate that blood flow and transport of macromolecules in the cardiovascular system and tissues are essential to understand the genesis and progression of arterial diseases and for the effective implementation of arterial grafts, as well as to devise efficient drug delivery mechanisms. In the present study, we use computational fluid dynamics to simulate the blood flow and transport of low-density lipoproteins (LDL) in a three-dimensional and permeable T junction. The Navier-Stokes equation, Darcy's Law, and the advective diffusion equations are the mathematical models used to simulate the flow and transport phenomena of the system. In the numeric model to implement the finite volume method, we used the computational fluid dynamics software Fluent 6.1. The simulation shows higher LDL concentration in the luminal surface at the junction under physiologic flow conditions. At 1 mm depth into the artery from the luminal surface, the LDL concentration is approximately 40% of the lumenal concentration, and at 2 mm depth, it reduces to 20%. Ultimately, the concentration drops further and reaches zero at the outer wall boundary.

Three-dimensional free vibration of functionally graded truncated conical shells subjected to thermal environment

Energy Technology Data Exchange (ETDEWEB)

Malekzadeh, P., E-mail: p_malekz@yahoo.com [Department of Mechanical Engineering, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of); Fiouz, A.R.; Sobhrouyan, M. [Department of Civil Engineering, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of)

2012-01-15

A three-dimensional (3D) free vibration analysis of the functionally graded (FG) truncated conical shells subjected to thermal environment is presented. The material properties are assumed to be temperature-dependent and graded in the radius direction, which can vary according to a simple power law distribution. The initial thermal stresses are obtained accurately by solving the thermoelastic equilibrium equations and by considering the two-dimensional axisymmetric temperature distribution in the shell. The differential quadrature method (DQM) as an efficient and accurate numerical tool is adopted to solve the thermal and thermo-mechanical governing equations. For this purpose, a mapping technique is employed to transform the cross section of the shell into the computational domain of DQM. The convergence behavior of the method is numerically demonstrated and comparison studies with the available solutions in the literature are performed. The effects of temperature dependence of material properties, geometrical parameters, material graded index, thermal and mechanical boundary conditions on the frequency parameters of the FG truncated conical shells are carried out. - Highlights: Black-Right-Pointing-Pointer 3D free vibration analysis of the functionally graded truncated conical shells is presented. Black-Right-Pointing-Pointer Two-dimensional axisymmetric temperature distribution in the shell is assumed. Black-Right-Pointing-Pointer The material properties are assumed to be temperature-dependent. Black-Right-Pointing-Pointer Initial thermal stresses due to thermal environment are evaluated accurately and included. Black-Right-Pointing-Pointer Representing the effects of different parameters on the non-dimensional frequencies.

Detection of Streptococcus pneumoniae in whole blood by PCR.

Science.gov (United States)

Zhang, Y; Isaacman, D J; Wadowsky, R M; Rydquist-White, J; Post, J C; Ehrlich, G D

1995-03-01

Streptococcus pneumoniae is a major cause of bacteremia in both children and adults. Currently, the diagnosis of pneumococcal bacteremia relies on the isolation and identification of the bacteria from blood cultures. We have developed a sensitive assay for the detection of S. pneumoniae in whole blood by the PCR. A specific primer-probe set (JM201 and JM202 primers with JM204 probe) designed from the penicillin-binding protein 2B gene was demonstrated to reproducibly detect between 10 and 100 fg of input purified S. pneumoniae DNA. This assay system was shown to be inclusive for all strains of S. pneumoniae evaluated, including 15 different serotypes and a battery of penicillin-resistant and -sensitive strains. The specificity of this PCR-based assay was demonstrated by its inability to support amplification from a series of human, bacterial, and yeast genomic DNAs. A general specimen preparation method which should be suitable for the purification of DNA from any pathogens in whole blood was developed. With this protocol it was possible to detect S. pneumoniae-specific DNA from whole blood specimens inoculated with as little as 4 CFU/ml. Copurified human blood DNA, ranging from 0 to 4.5 micrograms per PCR, did not affect the sensitivity of S. pneumoniae detection by PCR. A blinded clinical trial was used to compare the PCR-based assay with standard microbiological blood culture for the detection of S. pneumoniae bacteremia in 36 specimens obtained from pediatric patients seen in the emergency room of Children's Hospital of Pittsburgh. With culture as the "gold standard," the PCR-based assay had a sensitivity of 80% (4 of 5 culture-positive specimens were PCR positive) and a specificity of 84% (26 of 31 culture-negative specimens were PCR negative). However, three patients whose specimens were PCR positive and culture negative had histories suggestive of bacteremia, including recent positive blood cultures, treatment with antibiotics, cellulitis, and multiple

Electromagnetic field in higher-dimensional black-hole spacetimes

International Nuclear Information System (INIS)

Krtous, Pavel

2007-01-01

A special test electromagnetic field in the spacetime of the higher-dimensional generally rotating NUT-(anti-)de Sitter black hole is found. It is adjusted to the hidden symmetries of the background represented by the principal Killing-Yano tensor. Such an electromagnetic field generalizes the field of charged black hole in four dimensions. In higher dimensions, however, the gravitational backreaction of such a field cannot be consistently solved

Automated typing of red blood cell and platelet antigens: a whole-genome sequencing study.

Science.gov (United States)

Lane, William J; Westhoff, Connie M; Gleadall, Nicholas S; Aguad, Maria; Smeland-Wagman, Robin; Vege, Sunitha; Simmons, Daimon P; Mah, Helen H; Lebo, Matthew S; Walter, Klaudia; Soranzo, Nicole; Di Angelantonio, Emanuele; Danesh, John; Roberts, David J; Watkins, Nick A; Ouwehand, Willem H; Butterworth, Adam S; Kaufman, Richard M; Rehm, Heidi L; Silberstein, Leslie E; Green, Robert C

2018-06-01

There are more than 300 known red blood cell (RBC) antigens and 33 platelet antigens that differ between individuals. Sensitisation to antigens is a serious complication that can occur in prenatal medicine and after blood transfusion, particularly for patients who require multiple transfusions. Although pre-transfusion compatibility testing largely relies on serological methods, reagents are not available for many antigens. Methods based on single-nucleotide polymorphism (SNP) arrays have been used, but typing for ABO and Rh-the most important blood groups-cannot be done with SNP typing alone. We aimed to develop a novel method based on whole-genome sequencing to identify RBC and platelet antigens. This whole-genome sequencing study is a subanalysis of data from patients in the whole-genome sequencing arm of the MedSeq Project randomised controlled trial (NCT01736566) with no measured patient outcomes. We created a database of molecular changes in RBC and platelet antigens and developed an automated antigen-typing algorithm based on whole-genome sequencing (bloodTyper). This algorithm was iteratively improved to address cis-trans haplotype ambiguities and homologous gene alignments. Whole-genome sequencing data from 110 MedSeq participants (30 × depth) were used to initially validate bloodTyper through comparison with conventional serology and SNP methods for typing of 38 RBC antigens in 12 blood-group systems and 22 human platelet antigens. bloodTyper was further validated with whole-genome sequencing data from 200 INTERVAL trial participants (15 × depth) with serological comparisons. We iteratively improved bloodTyper by comparing its typing results with conventional serological and SNP typing in three rounds of testing. The initial whole-genome sequencing typing algorithm was 99·5% concordant across the first 20 MedSeq genomes. Addressing discordances led to development of an improved algorithm that was 99·8% concordant for the remaining 90 Med

Parotid gland sparing effect by computed tomography-based modified lower field margin in whole brain radiotherapy

International Nuclear Information System (INIS)

Cho, Oyeon; Chun, Mi Son; Oh, Young Taek; Kim, Mi Hwa; Park, Hae Jin; Nam, Sang Soo; Heo, Jae Sung; Noh, O Kyu; Park, Sung Ho

2013-01-01

Parotid gland can be considered as a risk organ in whole brain radiotherapy (WBRT). The purpose of this study is to evaluate the parotid gland sparing effect of computed tomography (CT)-based WBRT compared to 2-dimensional plan with conventional field margin. From January 2008 to April 2011, 53 patients underwent WBRT using CT-based simulation. Bilateral two-field arrangement was used and the prescribed dose was 30 Gy in 10 fractions. We compared the parotid dose between 2 radiotherapy plans using different lower field margins: conventional field to the lower level of the atlas (CF) and modified field fitted to the brain tissue (MF). Averages of mean parotid dose of the 2 protocols with CF and MF were 17.4 Gy and 8.7 Gy, respectively (p 98% of prescribed dose were 99.7% for CF and 99.5% for MF. Compared to WBRT with CF, CT-based lower field margin modification is a simple and effective technique for sparing the parotid gland, while providing similar dose coverage of the whole brain.

Whole brain radiotherapy for brain metastases: The technique of irradiation influences the dose to parotid glands

International Nuclear Information System (INIS)

Loos, G.; Paulon, R.; Verrelle, P.; Lapeyre, M.

2012-01-01

In the treatment of brain metastases, whole brain radiotherapy can be carried out according two distinct methods: one using multi-leaf collimator for field shaping and protection of organs at risk, and a second one is to make a rotation of the field to avoid the eyes. The aim of the study was to compare for 10 patients the dose distributions at organs at risk for each method. Patients received 30 Gy in 10 fractions. Except for parotid glands, the dose received by organs at risk and the planning target volume was the same with each method. For whole brain radiotherapy, excluding the cisterna cerebellomedullaris, the mean parotid dose was 9.63 Gy using the multi-leaf collimator versus 12.32 Gy using the field rotation (P = 0.04). For whole brain radiotherapy including the cisterna cerebellomedullaris, the mean parotid dose was 11.12 Gy using the multi-leaf collimator versus 20.06 Gy using field rotation (P < 0.001). Using the multi-leaf collimator seems recommended for whole brain radiotherapy, to reduce the dose to the parotids. (authors)

Quantum Statistical Entropy of Five-Dimensional Black Hole

Institute of Scientific and Technical Information of China (English)

ZHAO Ren; WU Yue-Qin; ZHANG Sheng-Li

2006-01-01

The generalized uncertainty relation is introduced to calculate quantum statistic entropy of a black hole.By using the new equation of state density motivated by the generalized uncertainty relation, we discuss entropies of Bose field and Fermi field on the background of the five-dimensional spacetime. In our calculation, we need not introduce cutoff. There is not the divergent logarithmic term as in the original brick-wall method. And it is obtained that the quantum statistic entropy corresponding to black hole horizon is proportional to the area of the horizon. Further it is shown that the entropy of black hole is the entropy of quantum state on the surface of horizon. The black hole's entropy is the intrinsic property of the black hole. The entropy is a quantum effect. It makes people further understand the quantum statistic entropy.

Quantum Statistical Entropy of Five-Dimensional Black Hole

International Nuclear Information System (INIS)

Zhao Ren; Zhang Shengli; Wu Yueqin

2006-01-01

The generalized uncertainty relation is introduced to calculate quantum statistic entropy of a black hole. By using the new equation of state density motivated by the generalized uncertainty relation, we discuss entropies of Bose field and Fermi field on the background of the five-dimensional spacetime. In our calculation, we need not introduce cutoff. There is not the divergent logarithmic term as in the original brick-wall method. And it is obtained that the quantum statistic entropy corresponding to black hole horizon is proportional to the area of the horizon. Further it is shown that the entropy of black hole is the entropy of quantum state on the surface of horizon. The black hole's entropy is the intrinsic property of the black hole. The entropy is a quantum effect. It makes people further understand the quantum statistic entropy.

Whole brain helical Tomotherapy with integrated boost for brain metastases in patients with malignant melanoma–a randomized trial

International Nuclear Information System (INIS)

Hauswald, Henrik; Habl, Gregor; Krug, David; Kehle, Denise; Combs, Stephanie E; Bermejo, Justo Lorenzo; Debus, Jürgen; Sterzing, Florian

2013-01-01

Patients with malignant melanoma may develop brain metastases during the course of the disease, requiring radiotherapeutic treatment. In patients with 1–3 brain metastases, radiosurgery has been established as a treatment option besides surgery. For patients with 4 or more brain metastases, whole brain radiotherapy is considered the standard treatment. In certain patients with brain metastases, radiation treatment using whole brain helical Tomotherapy with integrated boost and hippocampal-sparing may improve prognosis of these patients. The present prospective, randomized two-armed trial aims to exploratory investigate the treatment response to conventional whole brain radiotherapy applying 30 Gy in 10 fractions versus whole brain helical Tomotherapy applying 30 Gy in 10 fractions with an integrated boost of 50 Gy to the brain metastases as well as hippocampal-sparing in patients with brain metastases from malignant melanoma. The main inclusion criteria include magnetic resonance imaging confirmed brain metastases from a histopathologically confirmed malignant melanoma in patients with a minimum age of 18 years. The main exclusion criteria include a previous radiotherapy of the brain and not having recovered from acute high-grade toxicities of prior therapies. The primary endpoint is treatment-related toxicity. Secondary endpoints include imaging response, local and loco-regional progression-free survival, overall survival and quality of life

Does whole blood coagulation analysis reflect developmental haemostasis?

DEFF Research Database (Denmark)

Ravn, Hanne Berg; Andreasen, Jo Bønding; Hvas, Anne-Mette

2017-01-01

.05), but there was no sign of developmental changes in whole blood coagulation assessment when applying ROTEM, apart from clotting time in the EXTEM assay (P reach statistical significance. Citrate-anticoagulated blood showed...

Black grape extract supplementation attenuates blood oxidative stress in response to acute exercise

Directory of Open Access Journals (Sweden)

A Skarpańska-Stejnborn

2010-03-01

Full Text Available The flavonoid-rich active compound in grapes is claimed to be one of the most important natural products. Hence, the objective of our research was to study parameters of the prooxidative-antioxidative balance in athletes supplied with Panace-Vid 2000® preparation consisting of black wine grape extract (Vitis vinifera. The study was carried out on 22 male rowers. The subjects from the supplemented group (n=10 were given one gelatin capsule containing Panace-Vid 2000® three times a day, for six weeks, while the control group (n=12 was given placebo. Before and after the supplementation period, the athletes performed a physical exercise test on the rowing ergometer; varying between 40 and 90% of maximal aerobic power. Each 3-min exercise session was followed by thirty seconds of rest. Blood was sampled from the rowers before the exercise test, one minute after its completion, and after a 24-h recovery period. The activity of antioxidative enzymes (superoxide dismutase, glutathione peroxidase was determined and the concentration of thiobarbituric acid-reactive substances was measured in the hemolysate of red blood cells. The Total Antioxidant Capacity was determined in the blood plasma. The concentration of lactic acid was measured in the whole blood. An analysis of the results revealed that the supply of grape extract, in the form of Panace-Vid 2000® preparation, contributed to a significant increase in plasma antioxidative capacity and to an insignificant increase in superoxide dismutase, as well as a lower activity of glutathione peroxidase and reduced concentration of lipid peroxidation product levels.

The Phase Transition of Higher Dimensional Charged Black Holes

International Nuclear Information System (INIS)

Li, Huaifan; Zhao, Ren; Zhang, Lichun; Guo, Xiongying

2016-01-01

We have studied phase transitions of higher dimensional charge black hole with spherical symmetry. We calculated the local energy and local temperature and find that these state parameters satisfy the first law of thermodynamics. We analyze the critical behavior of black hole thermodynamic system by taking state parameters (Q,Φ) of black hole thermodynamic system, in accordance with considering the state parameters (P,V) of van der Waals system, respectively. We obtain the critical point of black hole thermodynamic system and find that the critical point is independent of the dual independent variables we selected. This result for asymptotically flat space is consistent with that for AdS spacetime and is intrinsic property of black hole thermodynamic system.

Three-dimensional, automated, real-time video system for tracking limb motion in brain-machine interface studies.

Science.gov (United States)

Peikon, Ian D; Fitzsimmons, Nathan A; Lebedev, Mikhail A; Nicolelis, Miguel A L

2009-06-15

Collection and analysis of limb kinematic data are essential components of the study of biological motion, including research into biomechanics, kinesiology, neurophysiology and brain-machine interfaces (BMIs). In particular, BMI research requires advanced, real-time systems capable of sampling limb kinematics with minimal contact to the subject's body. To answer this demand, we have developed an automated video tracking system for real-time tracking of multiple body parts in freely behaving primates. The system employs high-contrast markers painted on the animal's joints to continuously track the three-dimensional positions of their limbs during activity. Two-dimensional coordinates captured by each video camera are combined and converted to three-dimensional coordinates using a quadratic fitting algorithm. Real-time operation of the system is accomplished using direct memory access (DMA). The system tracks the markers at a rate of 52 frames per second (fps) in real-time and up to 100fps if video recordings are captured to be later analyzed off-line. The system has been tested in several BMI primate experiments, in which limb position was sampled simultaneously with chronic recordings of the extracellular activity of hundreds of cortical cells. During these recordings, multiple computational models were employed to extract a series of kinematic parameters from neuronal ensemble activity in real-time. The system operated reliably under these experimental conditions and was able to compensate for marker occlusions that occurred during natural movements. We propose that this system could also be extended to applications that include other classes of biological motion.

Global geometry of two-dimensional charged black holes

International Nuclear Information System (INIS)

Frolov, Andrei V.; Kristjansson, Kristjan R.; Thorlacius, Larus

2006-01-01

The semiclassical geometry of charged black holes is studied in the context of a two-dimensional dilaton gravity model where effects due to pair-creation of charged particles can be included in a systematic way. The classical mass-inflation instability of the Cauchy horizon is amplified and we find that gravitational collapse of charged matter results in a spacelike singularity that precludes any extension of the spacetime geometry. At the classical level, a static solution describing an eternal black hole has timelike singularities and multiple asymptotic regions. The corresponding semiclassical solution, on the other hand, has a spacelike singularity and a Penrose diagram like that of an electrically neutral black hole. Extremal black holes are destabilized by pair-creation of charged particles. There is a maximally charged solution for a given black hole mass but the corresponding geometry is not extremal. Our numerical data exhibits critical behavior at the threshold for black hole formation

Pair creation of higher dimensional black holes on a de Sitter background

International Nuclear Information System (INIS)

Dias, Oscar J.C.; Lemos, Jose P.S.

2004-01-01

We study in detail the quantum process in which a pair of black holes is created in a higher D-dimensional de Sitter (dS) background. The energy to materialize and accelerate the pair comes from the positive cosmological constant. The instantons that describe the process are obtained from the Tangherlini black hole solutions. Our pair creation rates reduce to the pair creation rate for Reissner-Nordstroem-dS solutions when D=4. Pair creation of black holes in the dS background becomes less suppressed when the dimension of the spacetime increases. The dS space is the only background in which we can discuss analytically the pair creation process of higher dimensional black holes, since the C-metric and the Ernst solutions, which describe, respectively, a pair accelerated by a string and by an electromagnetic field, are not known yet in a higher dimensional spacetime

Thermodynamics of (2 +1 )-dimensional black holes in Einstein-Maxwell-dilaton gravity

Science.gov (United States)

Dehghani, M.

2017-08-01

In this paper, the linearly charged three-dimensional Einstein's theory coupled to a dilatonic field has been considered. It has been shown that the dilatonic potential must be considered in a form of generalized Liouville-type potential. Two new classes of charged dilatonic black hole solutions, as the exact solutions to the Einstein-Maxwell-dilaton (EMd) gravity, have been obtained and their properties have been studied. The conserved charge and mass related to both of the new EMd black holes have been calculated. Through comparison of the thermodynamical extensive quantities (i.e., temperature and entropy) obtained from both, the geometrical and the thermodynamical methods, the validity of first law of black hole thermodynamics has been investigated for both of the new black holes we just obtained. At the final stage, making use of the canonical ensemble method and regarding the black hole heat capacity, the thermal stability or phase transition of the new black hole solutions have been analyzed. It has been shown that there is a specific range for the horizon radius in such a way that the black holes with the horizon radius in that range are locally stable. Otherwise, they are unstable and may undergo type one or type two phase transitions to be stabilized.

In vitro models of the blood-brain barrier

DEFF Research Database (Denmark)

Helms, Hans Christian Cederberg; Abbott, N Joan; Burek, Malgorzata

2016-01-01

The endothelial cells lining the brain capillaries separate the blood from the brain parenchyma. The endothelial monolayer of the brain capillaries serves both as a crucial interface for exchange of nutrients, gases, and metabolites between blood and brain, and as a barrier for neurotoxic...... components of plasma and xenobiotics. This "blood-brain barrier" function is a major hindrance for drug uptake into the brain parenchyma. Cell culture models, based on either primary cells or immortalized brain endothelial cell lines, have been developed, in order to facilitate in vitro studies of drug...... transport to the brain and studies of endothelial cell biology and pathophysiology. In this review, we aim to give an overview of established in vitro blood-brain barrier models with a focus on their validation regarding a set of well-established blood-brain barrier characteristics. As an ideal cell culture...

Specific cerebral perfusion patterns in three schizophrenia symptom dimensions.

Science.gov (United States)

Stegmayer, Katharina; Strik, Werner; Federspiel, Andrea; Wiest, Roland; Bohlhalter, Stephan; Walther, Sebastian

2017-12-01

Dimensional concepts such as the Research Domain Criteria initiative have been proposed to disentangle the heterogeneity of schizophrenia. One model introduced three neurobiologically informed behavioral dimensions: language, affectivity and motor behavior. To study the brain-behavior associations of these three dimensions, we investigated whether current behavioral alterations were linked to resting state perfusion in distinct brain circuits in schizophrenia. In total, 47 patients with schizophrenia spectrum disorders and 44 healthy controls were included. Psychopathology was assessed with the Positive And Negative Syndrome Scale and the Bern Psychopathology scale (BPS). The BPS provides severity ratings of three behavioral dimensions (language, affectivity and motor). Patients were classified according to the severity of alterations (severe, mild, no) in each dimension. Whole brain resting state cerebral blood flow (CBF) was compared between patient subgroups and controls. Two symptom dimensions were associated with distinct CBF changes. Behavioral alterations in the language dimension were linked to increased CBF in Heschl's gyrus. Altered affectivity was related to increased CBF in amygdala. The ratings of motor behavior instead were not specifically associated with CBF. Investigating behavioral alterations in three schizophrenia symptom dimensions identified distinct regional CBF changes in the language and limbic brain circuits. The results demonstrate a hitherto unknown segregation of pathophysiological pathways underlying a limited number of specific symptom dimensions in schizophrenia. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Glutamate Efflux at the Blood-Brain Barrier

DEFF Research Database (Denmark)

Cederberg-Helms, Hans Christian; Uhd-Nielsen, Carsten; Brodin, Birger

2014-01-01

is well known, however endothelial cells may also play an important role through mediating brain-to-blood L-glutamate efflux. Expression of excitatory amino acid transporters has been demonstrated in brain endothelial cells of bovine, human, murine, rat and porcine origin. These can account for high...... affinity concentrative uptake of L-glutamate from the brain interstitial fluid into the capillary endothelial cells. The mechanisms in between L-glutamate uptake in the endothelial cells and L-glutamate appearing in the blood are still unclear and may involve a luminal transporter for L......-glutamate, metabolism of L-glutamate and transport of metabolites or a combination of the two. However, both in vitro and in vivo studies have demonstrated blood-to-brain transport of L-glutamate, at least during pathological events. This review summarizes the current knowledge on the brain-to-blood L-glutamate efflux...

The comparing results of carcinoma between three-phase and delayed whole body bone scan

International Nuclear Information System (INIS)

Si Hongwei; Li Xianfeng

2004-01-01

Purpose: Three phase bone scan is an imaging technology in nuclear medicine, which composed of blood flow phase, blood pool phase and delayed phase and the last one is often performed in routine works in department of nuclear medicine. The purpose of this study is to evaluate the merit of three-phase bone scan.Methods: In this study, we chose 54 patients who were having an regional pain which caused by benign or malignant carcinoma that diagnosed by CT, X-ray, ECT, MRI or other examinations. The imaging were acquired simultaneously from both anterior and posterior views, after a bolus injection of 1110 MBq technetium-99m-labelled methylene diphosphonate (MDP), blood phase contains 20 frame sand 3 seconds per frame, blood pool phase contains 5 frames and 1 minute per frame, delayed phase was performed 2.5 hour later. According to the results of three-phase bone scan, the patients were divided into 2 groups: normal and abnormal groups. The abnormal group includes early phase positive,delay positive and all three phase positive sets. The comparing among the 3 sets were analyzed by chi-square test and other statistic means.Results: There were 54 patients who had suffered lung cancer, breast cancer and other cancer,involved in this study, 34 males and 20 females, ranged age 17 to 88 years, were normal in 15 cases,positive in 22 cases, the results in delayed phase were positive in 9 cases, blood flow and blood pool phase showed blood flow changes in 4 cases and soft tissue tumors were seen in 4 cases. Three phase bone scan was more sensitive than delayed whole body bone scan in detecting the abnormal sites (p 0.05) The sensitivity of detecting tumors in blood flow and blood pool phase,delayed phase were respectively lower than in three phase bone scan (p<0.001).Conclusion: It is more sensitivity of detecting tumor lesions in three phase bone scan than in delayed phase whole body bone scan and the changes of blood flow and soft tissue can be seen in three phase bone scan

Whole brain CT perfusion deficits using 320-detector-row CT scanner in TIA patients are associated with ABCD2 score.

Science.gov (United States)

Mehta, Bijal K; Mustafa, Ghulam; McMurtray, Aaron; Masud, Mohammed W; Gunukula, Sameer K; Kamal, Haris; Kandel, Amit; Beltagy, Abdelrahman; Li, Ping

2014-01-01

Transient ischemic attacks (TIA) are cerebral ischemic events without infarction. The uses of CT perfusion (CTP) techniques such as cerebral blood volume (CBV), time to peak (TTP), mean transit time (MTT) and cerebral blood flow (CBF) provide real time data about ischemia. It has been shown that CTP changes occur in less sensitive CTP scanners in patients with TIA. Larger detector row CTP (whole brain perfusion studies) may show that CTP abnormalities are more prevalent than previously noted. It is also unclear if these changes are associated with TIA severity. To demonstrate that TIA patients are associated with perfusion deficits using whole brain 320-detector-row CT perfusion, and to determine an association between ABCD2 score and perfusion deficit using whole brain perfusion. We retrospectively reviewed all TIA patients for CTP deficits from 2008-2010. Perfusion imaging was reviewed at admission; and it was determined if a perfusion deficit was present along with vascular territory involved. Of 364 TIA patients, 62 patients had CTP deficits. The largest group of patients had MCA territory involved with 48 of 62 patients (77.42%). The most common perfusion abnormality was increased TTP with 46 patients (74.19%). The ABCD2 score was reviewed in association with perfusion deficit. Increased age >60, severe hypertension (>180/100 mmHg), patients with speech abnormalities, and duration of symptoms >10 min were associated with a perfusion deficit but history of diabetes or minimal/moderate hypertension (140/90-179/99 mmHg) was not. There was no association between motor deficit and perfusion abnormality. Perfusion deficits are found in TIA patients using whole brain CTP and associated with components of the ABCD2 score.

Appearance and impact of post-operative intracranial clips and coils on whole-brain CT angiography and perfusion

International Nuclear Information System (INIS)

Roach, Cayce J.; Russell, Cheryl L.; Hanson, Eric H.; Bluett, Brent; Orrison, William W.

2012-01-01

Background: To evaluate the effect of vascular clips and endovascular coils placed for intracranial aneurysms and arteriovenous malformations on whole-brain computed tomography (CT) angiography and perfusion. Methods: A 320-detector row dynamic volume CT system imaged 11 patients following surgical placement of vascular clips or endovascular coils. The extent of clip and coil subtraction by automated software was evaluated using CT digital subtraction angiography and CT perfusion. Impact on CT perfusion values by retained intracranial devices was compared to age- and gender-matched controls. Results: Clip and coil subtraction on CT angiography was graded as good in 8 and moderate in 3 cases. A residual neck and additional aneurysm were noted in 1 of 11 patients. Post-procedural axial slice level CT perfusion values decreased in reliability with increasing proximity to the metallic devices secondary to beam hardening. However, the intracranial devices did not affect axial slice level CTP values of cerebral blood volume, cerebral blood flow and mean transit time outside of the level of the device. Time to peak values was globally decreased outside of the immediate vascular intervention region. Conclusions: Advances in CT technology have provided clinically useful subtraction of intracranial clips and coils. While CT perfusion values were altered in device subtraction areas and within beam hardening artifact areas; they can provide valuable postoperative information on whole-brain hemodynamics. In selected cases, the combination of CT angiography and whole-brain CT perfusion can offer an alternative to conventional angiography that is a more invasive option.

Whole-blood donation: blood donor suitability and adverse events.

Science.gov (United States)

Newman, Bruce H

2004-11-01

Approximately 3% to 3.5% of the US population donates whole blood each year. Physicians might be approached by a blood donor because of a donor suitability issue, a positive postdonation test, or a donation-related complication. Approximately 83% of blood donors successfully donate; but 13% are rejected because of a donor suitability issue; 1% have a positive test, which is often nonspecific or false-positive; and 2% to 4% of the phlebotomies are not successful. The most common adverse physical events based on donor interviews are bruise (23%), sore arm (10%), fatigue (8%), and vasovagal reaction (7%), while uncommon events include nerve irritation (0.9%), syncope (0.1-0.3%), and arterial puncture (0.01%). One in 3400 donors (0.033%) report seeking outside medical care. Serious injuries occur but are very rare. More often, blood donors do well and feel satisfied with the blood donation experience.

Automated processing of whole blood units: operational value and in vitro quality of final blood components.

Science.gov (United States)

Jurado, Marisa; Algora, Manuel; Garcia-Sanchez, Félix; Vico, Santiago; Rodriguez, Eva; Perez, Sonia; Barbolla, Luz

2012-01-01

The Community Transfusion Centre in Madrid currently processes whole blood using a conventional procedure (Compomat, Fresenius) followed by automated processing of buffy coats with the OrbiSac system (CaridianBCT). The Atreus 3C system (CaridianBCT) automates the production of red blood cells, plasma and an interim platelet unit from a whole blood unit. Interim platelet unit are pooled to produce a transfusable platelet unit. In this study the Atreus 3C system was evaluated and compared to the routine method with regards to product quality and operational value. Over a 5-week period 810 whole blood units were processed using the Atreus 3C system. The attributes of the automated process were compared to those of the routine method by assessing productivity, space, equipment and staffing requirements. The data obtained were evaluated in order to estimate the impact of implementing the Atreus 3C system in the routine setting of the blood centre. Yield and in vitro quality of the final blood components processed with the two systems were evaluated and compared. The Atreus 3C system enabled higher throughput while requiring less space and employee time by decreasing the amount of equipment and processing time per unit of whole blood processed. Whole blood units processed on the Atreus 3C system gave a higher platelet yield, a similar amount of red blood cells and a smaller volume of plasma. These results support the conclusion that the Atreus 3C system produces blood components meeting quality requirements while providing a high operational efficiency. Implementation of the Atreus 3C system could result in a large organisational improvement.

Black-blood thrombus imaging (BTI): a contrast-free cardiovascular magnetic resonance approach for the diagnosis of non-acute deep vein thrombosis.

Science.gov (United States)

Xie, Guoxi; Chen, Hanwei; He, Xueping; Liang, Jianke; Deng, Wei; He, Zhuonan; Ye, Yufeng; Yang, Qi; Bi, Xiaoming; Liu, Xin; Li, Debiao; Fan, Zhaoyang

2017-01-18

Deep vein thrombosis (DVT) is a common but elusive illness that can result in long-term disability or death. Accurate detection of thrombosis and assessment of its size and distribution are critical for treatment decision-making. In the present study, we sought to develop and evaluate a cardiovascular magnetic resonance (CMR) black-blood thrombus imaging (BTI) technique, based on delay alternating with nutation for tailored excitation black-blood preparation and variable flip angle turbo-spin-echo readout, for the diagnosis of non-acute DVT. METHODS: This prospective study was approved by institutional review board and informed consent obtained from all subjects. BTI was first conducted in 11 healthy subjects for parameter optimization and then conducted in 18 non-acute DVT patients to evaluate its diagnostic performance. Two clinically used CMR techniques, contrast-enhanced CMR venography (CE-MRV) and three dimensional magnetization prepared rapid acquisition gradient echo (MPRAGE), were also conducted in all patients for comparison. All images obtained from patients were analyzed on a per-segment basis. Using the consensus diagnosis of CE-MRV as the reference, the sensitivity (SE), specificity (SP), positive and negative predictive values (PPV and NPV), and accuracy (ACC) of BTI and MPRAGE as well as their diagnostic agreement with CE-MRV were calculated. Besides, diagnostic confidence and interreader diagnostic agreement were evaluated for all three techniques. BTI with optimized parameters effectively nulled the venous blood flow signal and allowed directly visualizing the thrombus within the black-blood lumen. Higher SE (90.4% vs 67.6%), SP (99.0% vs. 97.4%), PPV (95.4% vs. 85.6%), NPV (97.8% vs 92.9%) and ACC (97.4% vs. 91.8%) were obtained by BTI in comparison with MPRAGE. Good diagnostic confidence and excellent diagnostic and interreader agreements were achieved by BTI, which were superior to MPRAGE on detecting the chronic thrombus. BTI allows

Lifelong consumption of sodium selenite: gender differences on blood-brain barrier permeability in convulsive, hypoglycemic rats.

Science.gov (United States)

Seker, F Burcu; Akgul, Sibel; Oztas, Baria

2008-07-01

The aim of this study was to compare the effects of hypoglycemia and induced convulsions on the blood-brain barrier permeability in rats with or without lifelong administration of sodium selenite. There is a significant decrease of the blood-brain barrier permeability in three brain regions of convulsive, hypoglycemic male rats treated with sodium selenite when compared to sex-matched untreated rats (p0.05). The blood-brain barrier permeability of the left and right hemispheres of untreated, moderately hypoglycemic convulsive rats of both genders was better than their untreated counterparts (peffect against blood-brain barrier permeability during convulsions and that the effects of sodium selenite are gender-dependent.

Higher-dimensional black holes: hidden symmetries and separation of variables

International Nuclear Information System (INIS)

Frolov, Valeri P; Kubiznak, David

2008-01-01

In this paper, we discuss hidden symmetries in rotating black hole spacetimes. We start with an extended introduction which mainly summarizes results on hidden symmetries in four dimensions and introduces Killing and Killing-Yano tensors, objects responsible for hidden symmetries. We also demonstrate how starting with a principal CKY tensor (that is a closed non-degenerate conformal Killing-Yano 2-form) in 4D flat spacetime one can 'generate' the 4D Kerr-NUT-(A)dS solution and its hidden symmetries. After this we consider higher-dimensional Kerr-NUT-(A)dS metrics and demonstrate that they possess a principal CKY tensor which allows one to generate the whole tower of Killing-Yano and Killing tensors. These symmetries imply complete integrability of geodesic equations and complete separation of variables for the Hamilton-Jacobi, Klein-Gordon and Dirac equations in the general Kerr-NUT-(A)dS metrics

Measurement of brain perfusion, blood volume, and blood-brain barrier permeability, using dynamic contrast-enhanced T(1)-weighted MRI at 3 tesla

DEFF Research Database (Denmark)

Larsson, Henrik B W; Courivaud, Frédéric; Rostrup, Egill

2009-01-01

Assessment of vascular properties is essential to diagnosis and follow-up and basic understanding of pathogenesis in brain tumors. In this study, a procedure is presented that allows concurrent estimation of cerebral perfusion, blood volume, and blood-brain permeability from dynamic T(1)-weighted...... on a pixel-by-pixel basis of cerebral perfusion, cerebral blood volume, and blood-brain barrier permeability.......Assessment of vascular properties is essential to diagnosis and follow-up and basic understanding of pathogenesis in brain tumors. In this study, a procedure is presented that allows concurrent estimation of cerebral perfusion, blood volume, and blood-brain permeability from dynamic T(1)-weighted...... imaging of a bolus of a paramagnetic contrast agent passing through the brain. The methods are applied in patients with brain tumors and in healthy subjects. Perfusion was estimated by model-free deconvolution using Tikhonov's method (gray matter/white matter/tumor: 72 +/- 16/30 +/- 8/56 +/- 45 mL/100 g...

Determination of blood cell subtype concentrations from frozen whole blood samples using TruCount beads.

Science.gov (United States)

Langenskiöld, Cecilia; Mellgren, Karin; Abrahamsson, Jonas; Bemark, Mats

2016-06-24

In many studies it would be advantageous if blood samples could be collected and analyzed using flow cytometry at a later stage. Ideally, sample collection should involve little hands-on time, allow for long-term storage, and minimally influence the samples. Here we establish a flow cytometry antibody panel that can be used to determine granulocytes, monocytes, and lymphocyte subset concentrations in fresh and frozen whole blood using TruCount technology. The panel can be used on fresh whole-blood samples as well as whole-blood samples that have been frozen after mixing with 10% DMSO. Concentrations in frozen and fresh sample is highly correlated both when frozen within 4 h and the day after collection (r ≥ 0.98), and the estimated concentration in frozen samples was between 91 and 94% of that in fresh samples for all cell types. Using this method whole-blood samples can be frozen using a simple preparation method, and stored long-term before accurate determination of cell concentration. This allows for standardized analysis of the samples at a reference laboratory in multi-center studies. © 2016 International Clinical Cytometry Society. © 2016 International Clinical Cytometry Society.

Hawking radiation of five-dimensional charged black holes with scalar fields

Directory of Open Access Journals (Sweden)

Yan-Gang Miao

2017-09-01

Full Text Available We investigate the Hawking radiation cascade from the five-dimensional charged black hole with a scalar field coupled to higher-order Euler densities in a conformally invariant manner. We give the semi-analytic calculation of greybody factors for the Hawking radiation. Our analysis shows that the Hawking radiation cascade from this five-dimensional black hole is extremely sparse. The charge enhances the sparsity of the Hawking radiation, while the conformally coupled scalar field reduces this sparsity.

Hawking radiation from four-dimensional Schwarzschild black holes in M theory

International Nuclear Information System (INIS)

Das, S.R.; Mathur, S.D.; Ramadevi, P.

1999-01-01

Recently a method has been developed for relating four dimensional Schwarzschild black holes in M theory to near-extremal black holes in string theory with four charges, using suitably defined open-quotes boostsclose quotes and T dualities. We show that this method can be extended to obtain the emission rate of low energy massless scalars for the four dimensional Schwarzschild hole from the microscopic picture of radiation from the near extremal hole. copyright 1999 The American Physical Society

Three-dimensional, computer simulated navigation in endoscopic neurosurgery

Directory of Open Access Journals (Sweden)

Roberta K. Sefcik, BHA

2017-06-01

Conclusion: Three-dimensional, frameless neuronavigation systems are useful in endoscopic neurosurgery to assist in the pre-operative planning of potential trajectories and to help localize the pathology of interest. Neuronavigation appears to be accurate to <1–2 mm without issues related to brain shift. Further work is necessary in the investigation of the effect of neuronavigation on operative time, cost, and patient-centered outcomes.

Analyticity of event horizons of five-dimensional multi-black holes with nontrivial asymptotic structure

International Nuclear Information System (INIS)

Kimura, Masashi

2008-01-01

We show that there exist five-dimensional multi-black hole solutions which have analytic event horizons when the space-time has nontrivial asymptotic structure, unlike the case of five-dimensional multi-black hole solutions in asymptotically flat space-time.

Three-dimensional Einstein-Klein-Gordon system in characteristic numerical relativity

International Nuclear Information System (INIS)

Barreto, W.; Silva, A. da; Lehner, L.; Gomez, R.; Rosales, L.; Winicour, J.

2005-01-01

We incorporate a massless scalar field into a three-dimensional code for the characteristic evolution of the gravitational field. The extended three-dimensional code for the Einstein-Klein-Gordon system is calibrated to be second-order convergent. It provides an accurate calculation of the gravitational and scalar radiation at infinity. As an application, we simulate the fully nonlinear evolution of an asymmetric scalar pulse of ingoing radiation propagating toward an interior Schwarzschild black hole and compute the backscattered scalar and gravitational outgoing radiation patterns. The amplitudes of the scalar and gravitational outgoing radiation modes exhibit the predicted power law scaling with respect to the amplitude of the initial data. For the scattering of an axisymmetric scalar field, the final ring down matches the complex frequency calculated perturbatively for the l=2 quasinormal mode

A cardy formula for three-point coefficients or how the black hole got its spots

Energy Technology Data Exchange (ETDEWEB)

Kraus, Per [Department of Physics and Astronomy, University of California,Los Angeles, CA 90095 (United States); Maloney, Alexander [Physics Department, McGill University,Montréal, QC H3A 2T8 (Canada)

2017-05-31

Modular covariance of torus one-point functions constrains the three point function coefficients of a two dimensional CFT. This leads to an asymptotic formula for the average value of light-heavy-heavy three point coefficients, generalizing Cardy’s formula for the high energy density of states. The derivation uses certain asymptotic properties of one-point conformal blocks on the torus. Our asymptotic formula matches a dual AdS{sub 3} computation of one point functions in a black hole background. This is evidence that the BTZ black hole geometry emerges upon course-graining over a suitable family of heavy microstates.

Do patients with very few brain metastases from breast cancer benefit from whole-brain radiotherapy in addition to radiosurgery?

International Nuclear Information System (INIS)

Rades, Dirk; Huttenlocher, Stefan; Hornung, Dagmar; Blanck, Oliver; Schild, Steven E; Fischer, Dorothea

2014-01-01

An important issue in palliative radiation oncology is the whether whole-brain radiotherapy should be added to radiosurgery when treating a limited number of brain metastases. To optimize personalized treatment of cancer patients with brain metastases, the value of whole-brain radiotherapy should be described separately for each tumor entity. This study investigated the role of whole-brain radiotherapy added to radiosurgery in breast cancer patients. Fifty-eight patients with 1–3 brain metastases from breast cancer were included in this retrospective study. Of these patients, 30 were treated with radiosurgery alone and 28 with radiosurgery plus whole-brain radiotherapy. Both groups were compared for local control of the irradiated metastases, freedom from new brain metastases and survival. Furthermore, eight additional factors were analyzed including dose of radiosurgery, age at radiotherapy, Eastern Cooperative Oncology Group (ECOG) performance score, number of brain metastases, maximum diameter of all brain metastases, site of brain metastases, extra-cranial metastases and the time from breast cancer diagnosis to radiotherapy. The treatment regimen had no significant impact on local control in the univariate analysis (p = 0.59). Age ≤59 years showed a trend towards improved local control on univariate (p = 0.066) and multivariate analysis (p = 0.07). On univariate analysis, radiosurgery plus whole-brain radiotherapy (p = 0.040) and ECOG 0–1 (p = 0.012) showed positive associations with freedom from new brain metastases. Both treatment regimen (p = 0.039) and performance status (p = 0.028) maintained significance on multivariate analysis. ECOG 0–1 was positively correlated with survival on univariate analysis (p < 0.001); age ≤59 years showed a strong trend (p = 0.054). On multivariate analysis, performance status (p < 0.001) and age (p = 0.041) were significant. In breast cancer patients with few brain metastases, radiosurgery plus whole-brain

Portable vibration-assisted filtration device for on-site isolation of blood cells or pathogenic bacteria from whole human blood.

Science.gov (United States)

Kim, Yong Tae; Park, Kyun Joo; Kim, Seyl; Kim, Soon Ae; Lee, Seok Jae; Kim, Do Hyun; Lee, Tae Jae; Lee, Kyoung G

2018-03-01

Isolation of specific cells from whole blood is important to monitor disease prognosis and diagnosis. In this study, a vibration-assisted filtration (VF) device has been developed for isolation and recovery of specific cells such as leukocytes and pathogenic bacteria from human whole blood. The VF device is composed of three layers which was fabricated using injection molding with cyclic olefin copolymer (COC) pellets consisting of: a top layer with coin-type vibration motor (Ф = 10mm), a middle plate with a 1μm or 3μm-pore filter membrane to separate of Staphylococcus aureus (S. aureus) cells or leukocytes (i.e. white blood cells) respectively, and a bottom chamber with conical-shaped microstructure. One milliliter of human whole blood was injected into a sample loading chamber using a 3μm-pore filter equipped in the VF device and the coin-type vibration motor applied external vibration force by generating a rotational fluid which enhances the filtration velocity due to the prevention of the cell clogging on the filter membrane. The effluent blood such as erythrocytes, platelet, and plasma was collected at the bottom chamber while the leukocytes were sieved by the filter membrane. The vibration-assisted leukocyte separation was able to finish within 200s while leukocyte separation took 1200s without vibration. Moreover, we successfully separated S. aureus from human whole blood using a 1μm-pore filter equipped VF device and it was further confirmed by genetic analysis. The proposed VF device provides an advanced cell separation platform in terms of simplicity, fast separation, and portability in the fields of point-of-care diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

Instability in near-horizon geometries of even-dimensional Myers–Perry black holes

International Nuclear Information System (INIS)

Tanahashi, Norihiro; Murata, Keiju

2012-01-01

We study the gravitational, electromagnetic and scalar field perturbations on the near-horizon geometries of the even-dimensional extremal Myers–Perry black holes. By dimensional reduction, the perturbation equations are reduced to effective equations of motion in AdS 2 . We find that some modes in the gravitational perturbations violate the Breitenlöhner–Freedman bound in AdS 2 . This result suggests that the even-dimensional (near-)extremal Myers–Perry black holes are unstable against gravitational perturbations. We also discuss implications of our results to the Kerr–CFT correspondence. (paper)

In vitro blood-brain barrier permeability predictions for GABAA receptor modulating piperine analogs.

Science.gov (United States)

Eigenmann, Daniela Elisabeth; Dürig, Carmen; Jähne, Evelyn Andrea; Smieško, Martin; Culot, Maxime; Gosselet, Fabien; Cecchelli, Romeo; Helms, Hans Christian Cederberg; Brodin, Birger; Wimmer, Laurin; Mihovilovic, Marko D; Hamburger, Matthias; Oufir, Mouhssin

2016-06-01

The alkaloid piperine from black pepper (Piper nigrum L.) and several synthetic piperine analogs were recently identified as positive allosteric modulators of γ-aminobutyric acid type A (GABAA) receptors. In order to reach their target sites of action, these compounds need to enter the brain by crossing the blood-brain barrier (BBB). We here evaluated piperine and five selected analogs (SCT-66, SCT-64, SCT-29, LAU397, and LAU399) regarding their BBB permeability. Data were obtained in three in vitro BBB models, namely a recently established human model with immortalized hBMEC cells, a human brain-like endothelial cells (BLEC) model, and a primary animal (bovine endothelial/rat astrocytes co-culture) model. For each compound, quantitative UHPLC-MS/MS methods in the range of 5.00-500ng/mL in the corresponding matrix were developed, and permeability coefficients in the three BBB models were determined. In vitro predictions from the two human BBB models were in good agreement, while permeability data from the animal model differed to some extent, possibly due to protein binding of the screened compounds. In all three BBB models, piperine and SCT-64 displayed the highest BBB permeation potential. This was corroborated by data from in silico prediction. For the other piperine analogs (SCT-66, SCT-29, LAU397, and LAU399), BBB permeability was low to moderate in the two human BBB models, and moderate to high in the animal BBB model. Efflux ratios (ER) calculated from bidirectional permeability experiments indicated that the compounds were likely not substrates of active efflux transporters. Copyright © 2016 Elsevier B.V. All rights reserved.

Gamma knife radiosurgery for ten or more brain metastases. Analysis of the whole brain irradiation doses

International Nuclear Information System (INIS)

Nakaya, Kotaro; Hori, Tomokatsu; Izawa, Masahiro; Yamamoto, Masaaki

2002-01-01

Gamma knife (GK) radiosurgery has recently been recognized as the most powerful treatment modality in managing patients with brain metastasis, be they radioresistant or not, solitary or multiple. Very recently, this treatment has been employed in patients with numerous brain metastases, even those with 10 or more lesions. However, cumulative irradiation doses to the whole brain, with such treatment, remain unknown. Since the Gamma Plan ver. 5.10 (ver. 5.30 is presently available, Leksell Gamma Plan) became available in November, 1998, 105 GK procedures have been performed at our two facilities, Tokyo Women's Medical University and Katsuta Hospital Mito Gamma House. The median lesion number was 17, ranging 10-43, and the median cumulative volume of all tumors was 8.72 cm 3 , ranging 0.41-81.41 cm 3 . The selected doses at the lesion periphery ranged 12-25 Gy, the median being 20 Gy. Based on these treatment protocols, the cumulative irradiation dose was computed. The median cumulative irradiation dose to the whole brain was 4.83, ranging 2.16-8.51 Gy: the median integrated dose to the whole brain was 6.2 J, ranging 2.16-11.9 J. The median brain volumes receiving ≥2, ≥5, ≥10, ≥15 and ≥20 Gy were 1105 (range: 410-1501), 309 (46-1247), 64 (13-282), 24 (2-77), and 8 (0-40) cm 3 , respectively. The cumulative whole brain irradiation doses for patients with numerous radiosurgical targets were considered not to exceed the threshold level of normal brain necrosis. (author)

Altered whole-brain connectivity in albinism.

Science.gov (United States)

Welton, Thomas; Ather, Sarim; Proudlock, Frank A; Gottlob, Irene; Dineen, Robert A

2017-02-01

Albinism is a group of congenital disorders of the melanin synthesis pathway. Multiple ocular, white matter and cortical abnormalities occur in albinism, including a greater decussation of nerve fibres at the optic chiasm, foveal hypoplasia and nystagmus. Despite this, visual perception is largely preserved. It was proposed that this may be attributable to reorganisation among cerebral networks, including an increased interhemispheric connectivity of the primary visual areas. A graph-theoretic model was applied to explore brain connectivity networks derived from resting-state functional and diffusion-tensor magnetic resonance imaging data in 23 people with albinism and 20 controls. They tested for group differences in connectivity between primary visual areas and in summary network organisation descriptors. Main findings were supplemented with analyses of control regions, brain volumes and white matter microstructure. Significant functional interhemispheric hyperconnectivity of the primary visual areas in the albinism group were found (P = 0.012). Tests of interhemispheric connectivity based on the diffusion-tensor data showed no significant group difference (P = 0.713). Second, it was found that a range of functional whole-brain network metrics were abnormal in people with albinism, including the clustering coefficient (P = 0.005), although this may have been driven partly by overall differences in connectivity, rather than reorganisation. Based on the results, it was suggested that changes occur in albinism at the whole-brain level, and not just within the visual processing pathways. It was proposed that their findings may reflect compensatory adaptations to increased chiasmic decussation, foveal hypoplasia and nystagmus. Hum Brain Mapp 38:740-752, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Altered resting-state whole-brain functional networks of neonates with intrauterine growth restriction.

Science.gov (United States)

Batalle, Dafnis; Muñoz-Moreno, Emma; Tornador, Cristian; Bargallo, Nuria; Deco, Gustavo; Eixarch, Elisenda; Gratacos, Eduard

2016-04-01

The feasibility to use functional MRI (fMRI) during natural sleep to assess low-frequency basal brain activity fluctuations in human neonates has been demonstrated, although its potential to characterise pathologies of prenatal origin has not yet been exploited. In the present study, we used intrauterine growth restriction (IUGR) as a model of altered neurodevelopment due to prenatal condition to show the suitability of brain networks to characterise functional brain organisation at neonatal age. Particularly, we analysed resting-state fMRI signal of 20 neonates with IUGR and 13 controls, obtaining whole-brain functional networks based on correlations of blood oxygen level-dependent (BOLD) signal in 90 grey matter regions of an anatomical atlas (AAL). Characterisation of the networks obtained with graph theoretical features showed increased network infrastructure and raw efficiencies but reduced efficiency after normalisation, demonstrating hyper-connected but sub-optimally organised IUGR functional brain networks. Significant association of network features with neurobehavioral scores was also found. Further assessment of spatiotemporal dynamics displayed alterations into features associated to frontal, cingulate and lingual cortices. These findings show the capacity of functional brain networks to characterise brain reorganisation from an early age, and their potential to develop biomarkers of altered neurodevelopment. Copyright © 2016 Elsevier Ltd. All rights reserved.

An analysis of mobile whole blood collection labor efficiency.

Science.gov (United States)

Rose, William N; Dayton, Paula J; Raife, Thomas J

2011-07-01

Labor efficiency is desirable in mobile blood collection. There are few published data on labor efficiency. The variability in the labor efficiency of mobile whole blood collections was analyzed. We determined to improve our labor efficiency using lean manufacturing principles. Workflow changes in mobile collections were implemented with the goal of minimizing labor expenditures. To measure success, data on labor efficiency measured by units/hour/full-time equivalent (FTE) were collected. The labor efficiency in a 6-month period before the implementation of changes, and in months 1 to 6 and 7 to 12 after implementation was analyzed and compared. Labor efficiency in the 6-month period preceding implementation was 1.06 ± 0.4 units collected/hour/FTE. In months 1 to 6, labor efficiency declined slightly to 0.92 ± 0.4 units collected/hour/FTE (p = 0.016 vs. preimplementation). In months 7 to 12, the mean labor efficiency returned to preimplementation levels of 1.09 ±0.4 units collected/hour/FTE. Regression analysis correlating labor efficiency with total units collected per drive revealed a strong correlation (R(2) = 0.48 for the aggregate data from all three periods), indicating that nearly half of labor efficiency was associated with drive size. The lean-based changes in workflow were subjectively favored by employees and donors. The labor efficiency of our mobile whole blood drives is strongly influenced by size. Larger drives are more efficient, with diminishing returns above 40 units collected. Lean-based workflow changes were positively received by employees and donors. © 2011 American Association of Blood Banks.

Statistical Entropy of Four-Dimensional Extremal Black Holes

International Nuclear Information System (INIS)

Maldacena, J.M.; Strominger, A.

1996-01-01

String theory is used to count microstates of four-dimensional extremal black holes in compactifications with N=4 and N=8 supersymmetry. The result agrees for large charges with the Bekenstein-Hawking entropy. copyright 1996 The American Physical Society

Statistical Entropy of Nonextremal Four-Dimensional Black Holes and U-Duality

International Nuclear Information System (INIS)

Horowitz, G.T.; Lowe, D.A.; Maldacena, J.M.

1996-01-01

We identify the states in string theory which are responsible for the entropy of near-extremal rotating four-dimensional black holes in N=8 supergravity. For black holes far from extremality (with no rotation), the Bekenstein-Hawking entropy is exactly matched by a mysterious duality invariant extension of the formulas derived for near-extremal black holes states. copyright 1996 The American Physical Society

Pathogen reduction of whole blood: utility and feasibility.

Science.gov (United States)

Allain, J-P; Goodrich, R

2017-10-01

To collect information on pathogen reduction applied to whole blood. Pathogen reduction (PR) of blood components has been developed over the past two decades, and pathogen-reduced fresh-frozen plasma and platelet concentrates are currently in clinical use. High cost and incomplete coverage of components make PR out of reach for low- and middle-income countries (LMIC). However, should PR become applicable to whole blood (WB), the main product transfused in sub-Saharan Africa, and be compatible with the preparation of clinically suitable components, cost would be minimised, and a range of safety measures in place at high cost in developed areas would become redundant. All articles called with "pathogen reduction", "pathogen inactivation" and "whole blood" were retrieved from Medline. References in articles were utilised. One such PR technology (PRT) applied to WB has been developed and has shown efficacious against viruses, bacteria and parasites in vitro; and has been able to inactivate nucleated blood cells whilst retaining the ability to prepare components with acceptable characteristics. The efficacy of this WB PRT has been demonstrated in vivo using the inactivation of Plasmodium falciparum as a model and showing a high degree of correlation between in vitro and in vivo data. Obtaining further evidence of efficacy on other suitable targets is warranted. Shortening of the process, which is currently around 50 min, or increasing the number of units simultaneously processed would be necessary to make PRT WB conducive to LMIC blood services' needs. Even if not 100% effective against agents that are present in high pathogen load titres, WB PRT could massively impact blood safety in LMIC by providing safer products at an affordable cost. © 2017 British Blood Transfusion Society.

Linear waves on higher dimensional Schwarzschild black holes and Schwarzschild de Sitter spacetimes

OpenAIRE

Schlue, Volker

2012-01-01

I study linear waves on higher dimensional Schwarzschild black holes and Schwarzschild de Sitter spacetimes. In the first part of this thesis two decay results are proven for general finite energy solutions to the linear wave equation on higher dimensional Schwarzschild black holes. I establish uniform energy decay and improved interior first order energy decay in all dimensions with rates in accordance with the 3 + 1-dimensional case. The method of proof departs from earlier work on th...

Whole-brain blood flow and oxygen metabolism in the rat after halothane anesthesia

Energy Technology Data Exchange (ETDEWEB)

Gjedde, A; Hindfeldt, B [Cerebrovascular Research Center, Department of Neurology, The New York Hospital-Cornell Medical Center, New York, U.S.A.; Department of Neurology, University Hospital, Lund, Sweden)

1975-01-01

A recent modification of the Kety-Schmidt wash-out technique for /sup 133/xenon was used to measure whole-brain flow (CBF) and oxygen consumption (CMRsub(o2)) 1 to 4 hours after termination of halothane anesthesia in 15 Wistar rats. In this 3-hour experimental period, mean CBF and CMRsub(o2) were reduced to 29 and 43 percent of control values, respectively. CBF and CMRsub(o2) determined at the beginning and end of the experimental period were not significantly different from each other. Cerebral venous O/sub 2/ tension was significantly higher than in the control group, supporting recent suggestions of a primary, intrinsic effect of halothane on the homeostatic control of this variable. It is concluded that halothane is not useful for cerebral metabolic studies in the rat.

Three-dimensional hydrogel cell culture systems for modeling neural tissue

Science.gov (United States)

Frampton, John

Two-dimensional (2-D) neural cell culture systems have served as physiological models for understanding the cellular and molecular events that underlie responses to physical and chemical stimuli, control sensory and motor function, and lead to the development of neurological diseases. However, the development of three-dimensional (3-D) cell culture systems will be essential for the advancement of experimental research in a variety of fields including tissue engineering, chemical transport and delivery, cell growth, and cell-cell communication. In 3-D cell culture, cells are provided with an environment similar to tissue, in which they are surrounded on all sides by other cells, structural molecules and adhesion ligands. Cells grown in 3-D culture systems display morphologies and functions more similar to those observed in vivo, and can be cultured in such a way as to recapitulate the structural organization and biological properties of tissue. This thesis describes a hydrogel-based culture system, capable of supporting the growth and function of several neural cell types in 3-D. Alginate hydrogels were characterized in terms of their biomechanical and biochemical properties and were functionalized by covalent attachment of whole proteins and peptide epitopes. Methods were developed for rapid cross-linking of alginate hydrogels, thus permitting the incorporation of cells into 3-D scaffolds without adversely affecting cell viability or function. A variety of neural cell types were tested including astrocytes, microglia, and neurons. Cells remained viable and functional for longer than two weeks in culture and displayed process outgrowth in 3-D. Cell constructs were created that varied in cell density, type and organization, providing experimental flexibility for studying cell interactions and behavior. In one set of experiments, 3-D glial-endothelial cell co-cultures were used to model blood-brain barrier (BBB) structure and function. This co-culture system was

Affective three-dimensional brain-computer interface created using a prism array-based display

Science.gov (United States)

Mun, Sungchul; Park, Min-Chul

2014-12-01

To avoid the vergence-accommodation mismatch and provide a strong sense of presence to users, we applied a prism array-based display when presenting three-dimensional (3-D) objects. Emotional pictures were used as visual stimuli to increase the signal-to-noise ratios of steady-state visually evoked potentials (SSVEPs) because involuntarily motivated selective attention by affective mechanisms can enhance SSVEP amplitudes, thus producing increased interaction efficiency. Ten male and nine female participants voluntarily participated in our experiments. Participants were asked to control objects under three viewing conditions: two-dimension (2-D), stereoscopic 3-D, and prism. The participants performed each condition in a counter-balanced order. One-way repeated measures analysis of variance showed significant increases in the positive predictive values in the prism condition compared to the 2-D and 3-D conditions. Participants' subjective ratings of realness and engagement were also significantly greater in the prism condition than in the 2-D and 3-D conditions, while the ratings for visual fatigue were significantly reduced in the prism condition than in the 3-D condition. The proposed methods are expected to enhance the sense of reality in 3-D space without causing critical visual fatigue. In addition, people who are especially susceptible to stereoscopic 3-D may be able to use the affective brain-computer interface.

21 CFR 864.7500 - Whole blood hemoglobin assays.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Whole blood hemoglobin assays. 864.7500 Section 864.7500 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Hematology Kits and Packages § 864.7500 Whole...

Three-dimensional ICT reconstruction

International Nuclear Information System (INIS)

Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

2005-01-01

The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context, qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

Three-dimensional ICT reconstruction

International Nuclear Information System (INIS)

Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

2004-01-01

The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by order, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

Self-separation of blood plasma from whole blood during the capillary flow in microchannel

Science.gov (United States)

Nunna, Bharath Babu; Zhuang, Shiqiang; Lee, Eon Soo

2017-11-01

Self-separation of blood plasma from whole blood in microchannels is of great importance due to the enormous range of applications in healthcare and diagnostics. Blood is a multiphase complex fluid, composed of cells suspended in blood plasma. RBCs are the suspended particles whose shape changes during the flow of blood. The primary constituents of blood are erythrocytes or red blood cells (RBCs), leukocytes or white blood cells (WBCs), thrombocytes or platelets and blood plasma. The existence of RBCs in blood makes the blood a non-Newtonian fluid. The current study of separation of blood plasma from whole blood during self-driven flows in a single microchannel without bifurcation, by enhancing the capillary effects. The change in the capillary effect results in a change in contact angle which directly influences the capillary flow. The flow velocity directly influences the net force acting on the RBCs and influence the separation process. The experiments are performed on the PDMS microchannels with different contact angles by altering the surface characteristics using plasma treatment. The change in the separation length is studied during the capillary flow of blood in microchannel. Bharath Babu Nunna is a researcher in mechanical engineering and implementing the novel and innovative technologies in the biomedical devices to enhance the sensitivity of the disease diagnosis.

Support vector machine-based classification of Alzheimer's disease from whole-brain anatomical MRI

International Nuclear Information System (INIS)

Magnin, Benoit; Mesrob, Lilia; Kinkingnehun, Serge; Pelegrini-Issac, Melanie; Colliot, Olivier; Sarazin, Marie; Dubois, Bruno; Lehericy, Stephane; Benali, Habib

2009-01-01

We present and evaluate a new automated method based on support vector machine (SVM) classification of whole-brain anatomical magnetic resonance imaging to discriminate between patients with Alzheimer's disease (AD) and elderly control subjects. We studied 16 patients with AD [mean age ± standard deviation (SD)=74.1 ±5.2 years, mini-mental score examination (MMSE) = 23.1 ± 2.9] and 22 elderly controls (72.3±5.0 years, MMSE=28.5± 1.3). Three-dimensional T1-weighted MR images of each subject were automatically parcellated into regions of interest (ROIs). Based upon the characteristics of gray matter extracted from each ROI, we used an SVM algorithm to classify the subjects and statistical procedures based on bootstrap resampling to ensure the robustness of the results. We obtained 94.5% mean correct classification for AD and control subjects (mean specificity, 96.6%; mean sensitivity, 91.5%). Our method has the potential in distinguishing patients with AD from elderly controls and therefore may help in the early diagnosis of AD. (orig.)

Nernst Theorem and Statistical Entropy of 5-Dimensional Rotating Black Hole

Institute of Scientific and Technical Information of China (English)

ZHAO Ren; WU Yue-Qin; ZHANG Li-Chun

2003-01-01

In this paper, by using quantum statistical method, we obtain the partition function of Bose field and Fermi field on the background of the 5-dimensional rotating black hole. Then via the improved brick-wall method and membrane model, we calculate the entropy of Bose field and Fermi field of the black hole. And it is obtained that the entropy of the black hole is not only related to the area of the outer horizon but also is the function of inner horizon's area. In our results, there are not the left out term and the divergent logarithmic term in the original brick-wall method.The doubt that why the entropy of the scalar or Dirac field outside the event horizon is the entropy of the black hole in the original brick-wall method does not exist. The influence of spinning degeneracy of particles on entropy of the black hole is also given. It is shown that the entropy determined by the areas of the inner and outer horizons will approach zero,when the radiation temperature of the black hole approaches absolute zero. It satisfies Nernst theorem. The entropy can be taken as the Planck absolute entropy. We provide a way to study higher dimensional black hole.

Does whole-cell pertussis vaccine protect black South African infants?

African Journals Online (AJOL)

The whole-cell pertussis vaccine currently used in South Africa has not been adequately evaluated for post-vaccination events and immunogenicity. A trial of this vaccine combined with diphtheria and tetanus toxoids (DTP) was undertaken in 115 black babies who received primary vaccination at 2, 4 and 6 months of age.

Three-dimensional measurement system for crime scene documentation

Science.gov (United States)

Adamczyk, Marcin; Hołowko, Elwira; Lech, Krzysztof; Michoński, Jakub; MÄ czkowski, Grzegorz; Bolewicki, Paweł; Januszkiewicz, Kamil; Sitnik, Robert

2017-10-01

Three dimensional measurements (such as photogrammetry, Time of Flight, Structure from Motion or Structured Light techniques) are becoming a standard in the crime scene documentation process. The usage of 3D measurement techniques provide an opportunity to prepare more insightful investigation and helps to show every trace in the context of the entire crime scene. In this paper we would like to present a hierarchical, three-dimensional measurement system that is designed for crime scenes documentation process. Our system reflects the actual standards in crime scene documentation process - it is designed to perform measurement in two stages. First stage of documentation, the most general, is prepared with a scanner with relatively low spatial resolution but also big measuring volume - it is used for the whole scene documentation. Second stage is much more detailed: high resolution but smaller size of measuring volume for areas that required more detailed approach. The documentation process is supervised by a specialised application CrimeView3D, that is a software platform for measurements management (connecting with scanners and carrying out measurements, automatic or semi-automatic data registration in the real time) and data visualisation (3D visualisation of documented scenes). It also provides a series of useful tools for forensic technicians: virtual measuring tape, searching for sources of blood spatter, virtual walk on the crime scene and many others. In this paper we present our measuring system and the developed software. We also provide an outcome from research on metrological validation of scanners that was performed according to VDI/VDE standard. We present a CrimeView3D - a software-platform that was developed to manage the crime scene documentation process. We also present an outcome from measurement sessions that were conducted on real crime scenes with cooperation with Technicians from Central Forensic Laboratory of Police.

Whole brain radiotherapy with radiosensitizer for brain metastases

Directory of Open Access Journals (Sweden)

Viani Gustavo

2009-01-01

Full Text Available Abstract Purpose To study the efficacy of whole brain radiotherapy (WBRT with radiosensitizer in comparison with WBRT alone for patients with brain metastases in terms of overall survival, disease progression, response to treatment and adverse effects of treatment. Methods A meta-analysis of randomized controlled trials (RCT was performed in order to compare WBRT with radiosensitizer for brain metastases and WBRT alone. The MEDLINE, EMBASE, LILACS, and Cochrane Library databases, in addition to Trial registers, bibliographic databases, and recent issues of relevant journals were researched. Significant reports were reviewed by two reviewers independently. Results A total of 8 RCTs, yielding 2317 patients were analyzed. Pooled results from this 8 RCTs of WBRT with radiosensitizer have not shown a meaningful improvement on overall survival compared to WBRT alone OR = 1.03 (95% CI0.84–1.25, p = 0.77. Also, there was no difference in local brain tumor response OR = 0.8(95% CI 0.5 – 1.03 and brain tumor progression (OR = 1.11, 95% CI 0.9 – 1.3 when the two arms were compared. Conclusion Our data show that WBRT with the following radiosentizers (ionidamine, metronidazole, misonodazole, motexafin gadolinium, BUdr, efaproxiral, thalidomide, have not improved significatively the overall survival, local control and tumor response compared to WBRT alone for brain metastases. However, 2 of them, motexafin- gadolinium and efaproxiral have been shown in recent publications (lung and breast to have positive action in lung and breast carcinoma brain metastases in association with WBRT.

Comprehensive optical and data management infrastructure for high-throughput light-sheet microscopy of whole mouse brains.

Science.gov (United States)

Müllenbroich, M Caroline; Silvestri, Ludovico; Onofri, Leonardo; Costantini, Irene; Hoff, Marcel Van't; Sacconi, Leonardo; Iannello, Giulio; Pavone, Francesco S

2015-10-01

Comprehensive mapping and quantification of neuronal projections in the central nervous system requires high-throughput imaging of large volumes with microscopic resolution. To this end, we have developed a confocal light-sheet microscope that has been optimized for three-dimensional (3-D) imaging of structurally intact clarified whole-mount mouse brains. We describe the optical and electromechanical arrangement of the microscope and give details on the organization of the microscope management software. The software orchestrates all components of the microscope, coordinates critical timing and synchronization, and has been written in a versatile and modular structure using the LabVIEW language. It can easily be adapted and integrated to other microscope systems and has been made freely available to the light-sheet community. The tremendous amount of data routinely generated by light-sheet microscopy further requires novel strategies for data handling and storage. To complete the full imaging pipeline of our high-throughput microscope, we further elaborate on big data management from streaming of raw images up to stitching of 3-D datasets. The mesoscale neuroanatomy imaged at micron-scale resolution in those datasets allows characterization and quantification of neuronal projections in unsectioned mouse brains.

Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

Energy Technology Data Exchange (ETDEWEB)

Ono, Ichiro; Ohura, Takehiko; Kimura, Chu (Hokkaido Univ., Sapporo (Japan). School of Medicine) (and others)

1989-08-01

Three-dimensional computer tomography (3DCT) was performed in patients with various diseases to visualize stereoscopically the deformity of the craniofacial bones. The data obtained were analyzed by the 3DCT analyzing system. A new coordinate system was established using the median sagittal plane of the face (a plane passing through sella, nasion and basion) on the three-dimensional image. Three-dimensional profilograms were prepared for detailed analysis of the deformation of craniofacial bones for cleft lip and palate, mandibular prognathia and hemifacial microsomia. For patients, asymmetry in the frontal view and twist-formed complicated deformities were observed, as well as deformity of profiles in the anteroposterior and up-and-down directions. A newly developed technique allows three-dimensional visualization of changes in craniofacial deformity. It would aid in determining surgical strategy, including crani-facial surgery and maxillo-facial surgery, and in evaluating surgical outcome. (N.K.).

Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

International Nuclear Information System (INIS)

Ono, Ichiro; Ohura, Takehiko; Kimura, Chu

1989-01-01

Three-dimensional computer tomography (3DCT) was performed in patients with various diseases to visualize stereoscopically the deformity of the craniofacial bones. The data obtained were analyzed by the 3DCT analyzing system. A new coordinate system was established using the median sagittal plane of the face (a plane passing through sella, nasion and basion) on the three-dimensional image. Three-dimensional profilograms were prepared for detailed analysis of the deformation of craniofacial bones for cleft lip and palate, mandibular prognathia and hemifacial microsomia. For patients, asymmetry in the frontal view and twist-formed complicated deformities were observed, as well as deformity of profiles in the anteroposterior and up-and-down directions. A newly developed technique allows three-dimensional visualization of changes in craniofacial deformity. It would aid in determining surgical strategy, including crani-facial surgery and maxillo-facial surgery, and in evaluating surgical outcome. (N.K.)

Hawking radiation of a high-dimensional rotating black hole

Energy Technology Data Exchange (ETDEWEB)

Zhao, Ren; Zhang, Lichun; Li, Huaifan; Wu, Yueqin [Shanxi Datong University, Institute of Theoretical Physics, Department of Physics, Datong (China)

2010-01-15

We extend the classical Damour-Ruffini method and discuss Hawking radiation spectrum of high-dimensional rotating black hole using Tortoise coordinate transformation defined by taking the reaction of the radiation to the spacetime into consideration. Under the condition that the energy and angular momentum are conservative, taking self-gravitation action into account, we derive Hawking radiation spectrums which satisfy unitary principle in quantum mechanics. It is shown that the process that the black hole radiates particles with energy {omega} is a continuous tunneling process. We provide a theoretical basis for further studying the physical mechanism of black-hole radiation. (orig.)

Regional cerebral blood flow and brain atrophy in senile dementia of Alzheimer type (SDAT)

International Nuclear Information System (INIS)

Okada, Kazunori; Kobayashi, Shoutai; Yamaguchi, Shuhei; Kitani, Mituhiro; Tsunematsu, Tokugoro

1987-01-01

To investigate the relationship between the reduction of cerebal blood flow and brain atrophy in SDAT, these were measured in 13 cases of senile dementia of Alzheimer type, and compared to 15 cases of multi-infarct Dementia, 39 cases of lacunar infarction without dementia (non-demented CVD group) and 69 cases of aged normal control. Brain atrophy was evaluated by two-dimensional method on CT film by digitizer and regional cerebral blood flow (rCBF) was measured by 133 Xe inhalation method. The degree of brain atrophy in SDAT was almost similar of that of MID. But it was more severe than that of non-demented group. MID showed the lowest rCBF among these groups. SDAT showed significantly lower rCBF than that of aged control, but rCBF in SDAT was equal to that of lacunar stroke without dementia. Focal reduction of cerebral blood flow in bilateral fronto-parietal and left occipital regions were observed in SDAT. Verbal intelligence score (Hasegawa's score) correlated with rCBF and brain atrophy index in MID, and a tendency of correlation between rCBF and brain atrophy in MID was also observed. However, there was no correlation among those indices in SDAT. These findings suggest that the loss of brain substance dose not correspond to the reduction of rCBF in SDAT and simultaneous measurement of rCBF and brain atrophy was useful to differ SDAT from MID. (author)

Effects of applying three-dimensional seismic isolation system on the seismic design of FBR

International Nuclear Information System (INIS)

Hirata, Kazuta; Yabana, Shuichi; Kanazawa, Kenji; Matsuda, Akihiro

1997-01-01

In this study conceptional three-dimensional seismic isolation system for fast breeder reactor (FBR) is proposed. Effects of applying three-dimensional seismic isolation system on the seismic design for the FBR equipment are evaluated quantitatively. From the evaluation, it is concluded following effects are expected by applying the three-dimensional seismic isolation system to the FBR and the effects are evaluated quantitatively. (1) Reduction of membrane thickness of the reactor vessel (2) Suppression of uplift of fuels by reducing vertical seismic response of the core (3) Reduction of the supports for the piping system (4) Three-dimensional base isolation system for the whole reactor building is advantageous to the combined isolation system of horizontal base isolation for the reactor building and vertical isolation for the equipment. (author)

Magnetic resonance imaging and three-dimensional ultrasound of carotid atherosclerosis: mapping regional differences.

Science.gov (United States)

Krasinski, Adam; Chiu, Bernard; Fenster, Aaron; Parraga, Grace

2009-04-01

To evaluate differences in carotid atherosclerosis measured using magnetic resonance imaging (MRI) and three-dimensional ultrasound (3DUS). Ten subject volunteers underwent carotid 3DUS and MRI (multislice black blood fast spin echo, T1-weighted contrast, double inversion recovery, 0.5 mm in-plane resolution, 2 mm slice, 3.0 T) within 1 hour. 3DUS and MR images were manually segmented by two observers providing vessel wall and lumen contours for quantification of vessel wall volume (VWV) and generation of carotid thickness maps. MRI VWV (1040 +/- 210 mm(3)) and 3DUS VWV (540 +/- 110 mm(3)) were significantly different (P Power Doppler US confirmed that heterogeneity in the common carotid artery in all patients resulted from apparent flow disturbances, not atherosclerotic plaque. MRI and 3DUS VWV were significantly different and carotid maps showed homogeneous thickness differences and heterogeneity in specific regions of interest identified as MR flow artifacts in the common carotid artery.

Cosmic censorship principle in two-dimensional charged extreme black hole

Energy Technology Data Exchange (ETDEWEB)

Wang Bin; Ru Keng Su [Fudan Univ., Shanghai (China). Dept. of Physics; Cheung, T. [Hong Kong City Univ., Hong Kong (China). Dept. of Physics

1999-10-01

By constructing a gedanken experiment, the authors prove that the event horizon of a two-dimensional charged extreme black hole cannot be removed. Singularities are found to be formed on the horizon through analyzing the fate of Hawking partner and application of Helliwell-Konkowski conjecture. The cosmic censorship principle is well protected in this black hole.

Adverse reactions in voluntary whole blood donors: Experience at ...

African Journals Online (AJOL)

Background: Whole blood donation, generally considered as a safe procedure, may be sometimes associated with adverse reactions and injuries of variable severity during or after the blood donation process. There are few reports of adverse events related to blood donation in the Democratic Republic of Congo.

Microfluidic-Based Bacteria Isolation from Whole Blood for Diagnostics of Blood Stream Infection.

Science.gov (United States)

Zelenin, Sergey; Ramachandraiah, Harisha; Faridi, Asim; Russom, Aman

2017-01-01

Bacterial blood stream infection (BSI) potentially leads to life-threatening clinical conditions and medical emergencies such as severe sepsis, septic shock, and multi organ failure syndrome. Blood culturing is currently the gold standard for the identification of microorganisms and, although it has been automated over the decade, the process still requires 24-72 h to complete. This long turnaround time, especially for the identification of antimicrobial resistance, is driving the development of rapid molecular diagnostic methods. Rapid detection of microbial pathogens in blood related to bloodstream infections will allow the clinician to decide on or adjust the antimicrobial therapy potentially reducing the morbidity, mortality, and economic burden associated with BSI. For molecular-based methods, there is a lot to gain from an improved and straightforward method for isolation of bacteria from whole blood for downstream processing.We describe a microfluidic-based sample-preparation approach that rapidly and selectively lyses all blood cells while it extracts intact bacteria for downstream analysis. Whole blood is exposed to a mild detergent, which lyses most blood cells, and then to osmotic shock using deionized water, which eliminates the remaining white blood cells. The recovered bacteria are 100 % viable, which opens up possibilities for performing drug susceptibility tests and for nucleic-acid-based molecular identification.

[Whole-blood transfusion for hemorrhagic shock resuscitation: two cases in Djibouti].

Science.gov (United States)

Cordier, P Y; Eve, O; Dehan, C; Topin, F; Menguy, P; Bertani, A; Massoure, P L; Kaiser, E

2012-01-01

Hemorrhagic shock requires early aggressive treatment, including transfusion of packed red blood cells and hemostatic resuscitation. In austere environments, when component therapy is not available, warm fresh whole-blood transfusion is a convenient treatment. It provides red blood cells, clotting factors, and functional platelets. Therefore it is commonly used in military practice to treat hemorrhagic shock in combat casualties. At Bouffard Hospital Center in Djibouti, the supply of packed red blood cells is limited, and apheresis platelets are unavailable. We used whole blood transfusion in two civilian patients with life-threatening non-traumatic hemorrhages. One had massive bleeding caused by disseminated intravascular coagulation due to septic shock; the second was a 39 year-old pregnant woman with uterine rupture. In both cases, whole blood transfusion (twelve and ten 500 mL bags respectively), combined with etiological treatment, enabled coagulopathy correction, hemorrhage control, and satisfactory recovery.

Regional cerebral blood flow in the patient with brain tumor

International Nuclear Information System (INIS)

Tsuchida, Shohei

1993-01-01

Regional cerebral blood flow (rCBF) was measured with xenon-enhanced CT (Xe-CT) in 21 cases of intracranial tumors (13 meningiomas, 5 gliomas, 3 metastatic brain tumors). Peritumoral edema was graded as mild, moderate or severe based on the extent of edema on CT and MRI. According to intratumoral blood flow distribution patterns, three patterns were classified as central type with relatively high blood flow at the center of the tumor, homogeneous type with an almost homogeneous blood flow distribution, and marginal type with relatively high blood flow at the periphery of the tumor. High grade astrocytoma and metastatic brain tumor showed marginal type blood flow and moderate or severe edema except in one case. Five meningiomas with severe peritumoral edema revealed marginal type blood flow and four with mild peritumoral edema showed central type blood flow, except for one case. No correlation was found between the extent of peritumoral edema and histological subtype, tumor size, location, duration of clinical history, vascularization on angiogram, and mean blood flow in the tumor. These results suggest that blood flow distribution patterns within the tumor may affect the extension of peritumoral edema. Pre- and postoperative rCBFs were evaluated with Xe-CT and IMP-SPECT in 7 cases, mean rCBF of peritumoral edema was 6.2 ml/100 g/min preoperatively, and discrepancy between rCBF on Xe-CT and that on IMP-SPECT was shown in the remote cortical region ipsilateral to the tumor. Postoperative rCBF revealed an improved blood flow in both adjacent and remote areas, suggesting that the decreased blood flow associated with brain tumors might be relieved after surgery. (author) 53 refs

Three-dimensional textural features of conventional MRI improve diagnostic classification of childhood brain tumours.

Science.gov (United States)

Fetit, Ahmed E; Novak, Jan; Peet, Andrew C; Arvanitits, Theodoros N

2015-09-01

The aim of this study was to assess the efficacy of three-dimensional texture analysis (3D TA) of conventional MR images for the classification of childhood brain tumours in a quantitative manner. The dataset comprised pre-contrast T1 - and T2-weighted MRI series obtained from 48 children diagnosed with brain tumours (medulloblastoma, pilocytic astrocytoma and ependymoma). 3D and 2D TA were carried out on the images using first-, second- and higher order statistical methods. Six supervised classification algorithms were trained with the most influential 3D and 2D textural features, and their performances in the classification of tumour types, using the two feature sets, were compared. Model validation was carried out using the leave-one-out cross-validation (LOOCV) approach, as well as stratified 10-fold cross-validation, in order to provide additional reassurance. McNemar's test was used to test the statistical significance of any improvements demonstrated by 3D-trained classifiers. Supervised learning models trained with 3D textural features showed improved classification performances to those trained with conventional 2D features. For instance, a neural network classifier showed 12% improvement in area under the receiver operator characteristics curve (AUC) and 19% in overall classification accuracy. These improvements were statistically significant for four of the tested classifiers, as per McNemar's tests. This study shows that 3D textural features extracted from conventional T1 - and T2-weighted images can improve the diagnostic classification of childhood brain tumours. Long-term benefits of accurate, yet non-invasive, diagnostic aids include a reduction in surgical procedures, improvement in surgical and therapy planning, and support of discussions with patients' families. It remains necessary, however, to extend the analysis to a multicentre cohort in order to assess the scalability of the techniques used. Copyright © 2015 John Wiley & Sons, Ltd.

Three dimensional strained semiconductors

Science.gov (United States)

Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui

2016-11-08

In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.

Whole Brain Irradiation With Hippocampal Sparing and Dose Escalation on Multiple Brain Metastases: A Planning Study on Treatment Concepts

International Nuclear Information System (INIS)

Prokic, Vesna; Wiedenmann, Nicole; Fels, Franziska; Schmucker, Marianne; Nieder, Carsten; Grosu, Anca-Ligia

2013-01-01

Purpose: To develop a new treatment planning strategy in patients with multiple brain metastases. The goal was to perform whole brain irradiation (WBI) with hippocampal sparing and dose escalation on multiple brain metastases. Two treatment concepts were investigated: simultaneously integrated boost (SIB) and WBI followed by stereotactic fractionated radiation therapy sequential concept (SC). Methods and Materials: Treatment plans for both concepts were calculated for 10 patients with 2-8 brain metastases using volumetric modulated arc therapy. In the SIB concept, the prescribed dose was 30 Gy in 12 fractions to the whole brain and 51 Gy in 12 fractions to individual brain metastases. In the SC concept, the prescription was 30 Gy in 12 fractions to the whole brain followed by 18 Gy in 2 fractions to brain metastases. All plans were optimized for dose coverage of whole brain and lesions, simultaneously minimizing dose to the hippocampus. The treatment plans were evaluated on target coverage, homogeneity, and minimal dose to the hippocampus and organs at risk. Results: The SIB concept enabled more successful sparing of the hippocampus; the mean dose to the hippocampus was 7.55 ± 0.62 Gy and 6.29 ± 0.62 Gy, respectively, when 5-mm and 10-mm avoidance regions around the hippocampus were used, normalized to 2-Gy fractions. In the SC concept, the mean dose to hippocampus was 9.8 ± 1.75 Gy. The mean dose to the whole brain (excluding metastases) was 33.2 ± 0.7 Gy and 32.7 ± 0.96 Gy, respectively, in the SIB concept, for 5-mm and 10-mm hippocampus avoidance regions, and 37.23 ± 1.42 Gy in SC. Conclusions: Both concepts, SIB and SC, were able to achieve adequate whole brain coverage and radiosurgery-equivalent dose distributions to individual brain metastases. The SIB technique achieved better sparing of the hippocampus, especially when a10-mm hippocampal avoidance region was used.

Radiolabeled cetuximab plus whole-brain irradiation (WBI) for the treatment of brain metastases from non-small cell lung cancer (NSCLC)

International Nuclear Information System (INIS)

Rades, Dirk; Nadrowitz, Roger; Buchmann, Inga; Meller, Birgit; Hunold, Peter; Noack, Frank; Schild, Steven E.

2010-01-01

Background and Purpose: The addition of systemic drugs to whole-brain irradiation has not improved the survival of patients with multiple brain metastases, most likely because the agents did not readily cross the blood-brain barrier (BBB). Radiolabeling of cetuximab was performed to investigate whether this antibody crosses the BBB. Case Report: A patient with multiple brain lesions from non-small cell lung cancer was investigated. The largest metastasis (40 x 33 x 27 mm) was selected the reference lesion. On day 1, 200 mg/m 2 cetuximab (0.25% hot and 99.75% cold antibody) were given. On day 3, 200 mg/m 2 cetuximab (cold antibody) were given. Weekly doses of 250 mg/m 2 cetuximab were administered for 3 months. Results: The reference lesion showed enhancement of radiolabeled cetuximab ( 123 I-Erbi) on scintigraphy; 123 I-Erbi crossed the BBB and accumulated in the lesion. The reference lesion measured 31 x 22 x 21 mm at 4 months. Enhancement of contrast medium was less pronounced. Conclusion: This is the first demonstration of cetuximab crossing the BBB and accumulating in brain metastasis. (orig.)

Radiolabeled cetuximab plus whole-brain irradiation (WBI) for the treatment of brain metastases from non-small cell lung cancer (NSCLC)

Energy Technology Data Exchange (ETDEWEB)

Rades, Dirk; Nadrowitz, Roger [Dept. of Radiation Oncology, Univ. of Luebeck (Germany); Buchmann, Inga; Meller, Birgit [Section of Nuclear Medicine, Univ. of Luebeck (Germany); Hunold, Peter [Dept. of Radiology, Univ. of Luebeck (Germany); Noack, Frank [Inst. of Pathology, Univ. of Luebeck (Germany); Schild, Steven E. [Dept. of Radiation Oncology, Mayo Clinic, Scottsdale, AZ (United States)

2010-08-15

Background and Purpose: The addition of systemic drugs to whole-brain irradiation has not improved the survival of patients with multiple brain metastases, most likely because the agents did not readily cross the blood-brain barrier (BBB). Radiolabeling of cetuximab was performed to investigate whether this antibody crosses the BBB. Case Report: A patient with multiple brain lesions from non-small cell lung cancer was investigated. The largest metastasis (40 x 33 x 27 mm) was selected the reference lesion. On day 1, 200 mg/m{sup 2} cetuximab (0.25% hot and 99.75% cold antibody) were given. On day 3, 200 mg/m{sup 2} cetuximab (cold antibody) were given. Weekly doses of 250 mg/m{sup 2} cetuximab were administered for 3 months. Results: The reference lesion showed enhancement of radiolabeled cetuximab ({sup 123}I-Erbi) on scintigraphy; {sup 123}I-Erbi crossed the BBB and accumulated in the lesion. The reference lesion measured 31 x 22 x 21 mm at 4 months. Enhancement of contrast medium was less pronounced. Conclusion: This is the first demonstration of cetuximab crossing the BBB and accumulating in brain metastasis. (orig.)

Egg beater as centrifuge: isolating human blood plasma from whole blood in resource-poor settings.

Science.gov (United States)

Wong, Amy P; Gupta, Malancha; Shevkoplyas, Sergey S; Whitesides, George M

2008-12-01

This paper demonstrates that a hand-powered egg beater can be modified to serve as a centrifuge for separating plasma from human whole blood. Immunoassays used to diagnose infectious diseases often require plasma from whole blood, and obtaining plasma typically requires electrically-powered centrifuges, which are not widely available in resource-limited settings. Human whole blood was loaded into polyethylene (PE) tubing, and the tubing was attached to the paddle of an egg beater. Spinning the paddle pelleted the blood cells to the distal end of the PE tubing; the plasma remained as the supernatant. A cholesterol assay (run on patterned paper) demonstrated the suitability of this plasma for use in diagnostic assays. The physics of the system was also analyzed as a guide for the selection of other rotating systems for use in centrifugation. Egg beaters, polyethylene tubing, and paper are readily available devices and supplies that can facilitate the use of point-of-care diagnostics at sites far from centralized laboratory facilities.

Usefulness of three dimensional reconstructive images for thoracic trauma induced fractures

Energy Technology Data Exchange (ETDEWEB)

Koh, Kyung Hun; Kim, Dong Hun; Kim, Young Sook; Byun, Joo Nam [Chosun University Hospital, Gwangju (Korea, Republic of)

2006-09-15

We wanted to evaluate the usefulness of three-dimensional reconstructive images using multidetector computed tomography (MDCT) for thoracic traumatic patients visiting emergency room. 76 patients with fractures of the 105 patients who visited our emergency room with complaints of thoracic trauma were analyzed retrospectively. All the patients had thoracic MDCT performed and the three-dimensional reconstructive images were taken. The fractures were confirmed by axial CT, the clinical information, whole body bone scanning and the multiplanar reformation images. Plain x-ray images were analyzed by the fractured sites in a blind comparison of two radiologists' readings, and then that finding was compared with the axial CT scans and the three-dimensional reconstructive images. The fracture sites were rib (n 68), sternum (n = 14), clavicle (n = 6), scapula (n = 3), spine (n = 5) and combined fractures (n = 14). Plain x-ray and axial CT scans had a correspondency of 0.555 for the rib fractures. Axial CT scans and the three-dimensional reconstructive images had a correspondency of .952. For sternal fractures, those values were 0.692 and 0.928, respectively. The axial CT scans and three-dimensional reconstructive images showed sensitivities of 94% and 91% for rib and other fractures, respectively, and 93% and 100% for sternal fracture, respectively. Three-dimensional reconstructive image had an especially high sensitivity for the diagnosis of sternal fracture. While evaluating thoracic trauma at the emergency room, the three-dimensional reconstructive image was useful to easily diagnose the extent of fracture and it was very sensitive for detecting sternal fracture.

Usefulness of three dimensional reconstructive images for thoracic trauma induced fractures

International Nuclear Information System (INIS)

Koh, Kyung Hun; Kim, Dong Hun; Kim, Young Sook; Byun, Joo Nam

2006-01-01

We wanted to evaluate the usefulness of three-dimensional reconstructive images using multidetector computed tomography (MDCT) for thoracic traumatic patients visiting emergency room. 76 patients with fractures of the 105 patients who visited our emergency room with complaints of thoracic trauma were analyzed retrospectively. All the patients had thoracic MDCT performed and the three-dimensional reconstructive images were taken. The fractures were confirmed by axial CT, the clinical information, whole body bone scanning and the multiplanar reformation images. Plain x-ray images were analyzed by the fractured sites in a blind comparison of two radiologists' readings, and then that finding was compared with the axial CT scans and the three-dimensional reconstructive images. The fracture sites were rib (n 68), sternum (n = 14), clavicle (n = 6), scapula (n = 3), spine (n = 5) and combined fractures (n = 14). Plain x-ray and axial CT scans had a correspondency of 0.555 for the rib fractures. Axial CT scans and the three-dimensional reconstructive images had a correspondency of .952. For sternal fractures, those values were 0.692 and 0.928, respectively. The axial CT scans and three-dimensional reconstructive images showed sensitivities of 94% and 91% for rib and other fractures, respectively, and 93% and 100% for sternal fracture, respectively. Three-dimensional reconstructive image had an especially high sensitivity for the diagnosis of sternal fracture. While evaluating thoracic trauma at the emergency room, the three-dimensional reconstructive image was useful to easily diagnose the extent of fracture and it was very sensitive for detecting sternal fracture

Whole-brain functional connectivity predicted by indirect structural connections

DEFF Research Database (Denmark)

Røge, Rasmus; Ambrosen, Karen Marie Sandø; Albers, Kristoffer Jon

2017-01-01

Modern functional and diffusion magnetic resonance imaging (fMRI and dMRI) provide data from which macro-scale networks of functional and structural whole brain connectivity can be estimated. Although networks derived from these two modalities describe different properties of the human brain, the...

Quantitative analysis of normal fetal medulla oblongata volume and flow by three-dimensional power Doppler ultrasound.

Science.gov (United States)

Shyu, Ing-Luen; Wang, Peng-Hui; Chen, Chih-Yao; Chen, Yi-Jen; Chang, Chia-Ming; Horng, Huann-Cheng; Yang, Ming-Jie; Yen, Ming-Shyen

2016-06-01

Assessment of the fetal medulla oblongata volume (MOV) and blood flow might be important in the evaluation of fetal brain growth. We used three-dimensional power Doppler ultrasound (3DPDUS) to assess the fetal MOV and blood flow index in normal gestation. The relationships between these parameters were further analyzed. We assessed the total volume and blood flow index of the fetal MO in normal pregnancies using a 3DPDUS (Voluson 730 Expert). The true sagittal plane over the fetal occipital area was measured by a 3D transabdominal probe to scan the fetal MO under the power Doppler mode. Then, we quantitatively assessed the total volume of the fetal MOV, mean gray area (MG), vascularization index (VI), and flow index (FI). A total of 106 fetuses, ranging from 19 weeks to 39 weeks of gestation, were involved in our study. The volume of the fetal MO was highly positively correlated with gestational age [correlation coefficient (r) = 0.686, p < 0.0001]. The MG was negatively correlated with gestational age [r = -0.544, p < 0.0001). VI and FI showed no significant correlation with gestational age (p = 0.123 and p = 0.219, respectively). 3DPDUS can be used to assess the fetal MOV and blood flow development quantitatively. Our study indicated that fetal MOV and blood flow correlated significantly with the advancement of gestational age. This information may serve as reference data for further studies of the fetal brain and blood flow under abnormal conditions. Copyright © 2016. Published by Elsevier B.V.

Black holes in brane worlds

Indian Academy of Sciences (India)

Abstract. A Kerr metric describing a rotating black hole is obtained on the three brane in a five-dimensional Randall-Sundrum brane world by considering a rotating five-dimensional black string in the bulk. We examine the causal structure of this space-time through the geodesic equations.

Isolation of human genomic DNA for genetic analysis from premature neonates: a comparison between newborn dried blood spots, whole blood and umbilical cord tissue

Science.gov (United States)

2013-01-01

Background Genotyping requires biological sample collection that must be reliable, convenient and acceptable for patients and clinicians. Finding the most optimal procedure of sample collection for premature neonates who have a very limited blood volume is a particular challenge. The aim of the current study was to evaluate the use of umbilical cord (UC) tissue and newborn dried blood spot (DBS)-extracted genomic DNA (gDNA) as an alternative to venous blood-derived gDNA from premature neonates for molecular genetic analysis. All samples were obtained from premature newborn infants between 24-32 weeks of gestation. Paired blood and UC samples were collected from 31 study participants. gDNA was extracted from ethylenediaminetetraacetic acid (EDTA) anticoagulant-treated blood samples (~500 μl) and newborn DBSs (n = 723) using QIAamp DNA Micro kit (Qiagen Ltd., Crawley, UK); and from UC using Qiagen DNAeasy Blood and Tissue kit (Qiagen Ltd., Crawley, UK). gDNA was quantified and purity confirmed by measuring the A260:A280 ratio. PCR amplification and pyrosequencing was carried out to determine suitability of the gDNA for molecular genetic analysis. Minor allele frequency of two unrelated single nucleotide polymorphisms (SNPs) was calculated using the entire cohort. Results Both whole blood samples and UC tissue provided good quality and yield of gDNA, which was considerably less from newborn DBS. The gDNA purity was also reduced after 3 years of storage of the newborn DBS. PCR amplification of three unrelated genes resulted in clear products in all whole blood and UC samples and 86%-100% of newborn DBS. Genotyping using pyrosequencing showed 100% concordance in the paired UC and whole blood samples. Minor allele frequencies of the two SNPs indicated that no maternal gDNA contamination occurred in the genotyping of the UC samples. Conclusions gDNAs from all three sources are suitable for standard PCR and pyrosequencing assays. Given that UC provide good quality

Exploring the brain on multiple scales with correlative two-photon and light sheet microscopy

Science.gov (United States)

Silvestri, Ludovico; Allegra Mascaro, Anna Letizia; Costantini, Irene; Sacconi, Leonardo; Pavone, Francesco S.

2014-02-01

One of the unique features of the brain is that its activity cannot be framed in a single spatio-temporal scale, but rather spans many orders of magnitude both in space and time. A single imaging technique can reveal only a small part of this complex machinery. To obtain a more comprehensive view of brain functionality, complementary approaches should be combined into a correlative framework. Here, we describe a method to integrate data from in vivo two-photon fluorescence imaging and ex vivo light sheet microscopy, taking advantage of blood vessels as reference chart. We show how the apical dendritic arbor of a single cortical pyramidal neuron imaged in living thy1-GFP-M mice can be found in the large-scale brain reconstruction obtained with light sheet microscopy. Starting from the apical portion, the whole pyramidal neuron can then be segmented. The correlative approach presented here allows contextualizing within a three-dimensional anatomic framework the neurons whose dynamics have been observed with high detail in vivo.

Neocortical Transplants in the Mammalian Brain Lack a Blood-Brain Barrier to Macromolecules

Science.gov (United States)

Rosenstein, Jeffrey M.

1987-02-01

In order to determine whether the blood-brain barrier was present in transplants of central nervous tissue, fetal neocortex, which already possesses blood-brain and blood-cerebrospinal fluid barriers to protein, was grafted into the undamaged fourth ventricle or directly into the neocortex of recipient rats. Horseradish peroxidase or a conjugated human immunoglobulin G-peroxidase molecule was systemically administered into the host. These proteins were detected within the cortical transplants within 2 minutes regardless of the age of the donor or postoperative time. At later times these compounds, which normally do not cross the blood-brain barrier, inundated the grafts and adjacent host brain and also entered the cerebrospinal fluid. Endogenous serum albumin detected immunocytochemically in untreated hosts had a comparable although less extensive distribution. Thus, transplants of fetal central nervous tissue have permanent barrier dysfunction, probably due to microvascular changes, and are not integrated physiologically within the host. Blood-borne compounds, either systemically administered or naturally occurring, which should never contact normal brain tissue, have direct access to these transplants and might affect neuronal function.

Novel automated blood separations validate whole cell biomarkers.

Directory of Open Access Journals (Sweden)

Douglas E Burger

Full Text Available Progress in clinical trials in infectious disease, autoimmunity, and cancer is stymied by a dearth of successful whole cell biomarkers for peripheral blood lymphocytes (PBLs. Successful biomarkers could help to track drug effects at early time points in clinical trials to prevent costly trial failures late in development. One major obstacle is the inaccuracy of Ficoll density centrifugation, the decades-old method of separating PBLs from the abundant red blood cells (RBCs of fresh blood samples.To replace the Ficoll method, we developed and studied a novel blood-based magnetic separation method. The magnetic method strikingly surpassed Ficoll in viability, purity and yield of PBLs. To reduce labor, we developed an automated platform and compared two magnet configurations for cell separations. These more accurate and labor-saving magnet configurations allowed the lymphocytes to be tested in bioassays for rare antigen-specific T cells. The automated method succeeded at identifying 79% of patients with the rare PBLs of interest as compared with Ficoll's uniform failure. We validated improved upfront blood processing and show accurate detection of rare antigen-specific lymphocytes.Improving, automating and standardizing lymphocyte detections from whole blood may facilitate development of new cell-based biomarkers for human diseases. Improved upfront blood processes may lead to broad improvements in monitoring early trial outcome measurements in human clinical trials.

Novel automated blood separations validate whole cell biomarkers.

Science.gov (United States)

Burger, Douglas E; Wang, Limei; Ban, Liqin; Okubo, Yoshiaki; Kühtreiber, Willem M; Leichliter, Ashley K; Faustman, Denise L

2011-01-01

Progress in clinical trials in infectious disease, autoimmunity, and cancer is stymied by a dearth of successful whole cell biomarkers for peripheral blood lymphocytes (PBLs). Successful biomarkers could help to track drug effects at early time points in clinical trials to prevent costly trial failures late in development. One major obstacle is the inaccuracy of Ficoll density centrifugation, the decades-old method of separating PBLs from the abundant red blood cells (RBCs) of fresh blood samples. To replace the Ficoll method, we developed and studied a novel blood-based magnetic separation method. The magnetic method strikingly surpassed Ficoll in viability, purity and yield of PBLs. To reduce labor, we developed an automated platform and compared two magnet configurations for cell separations. These more accurate and labor-saving magnet configurations allowed the lymphocytes to be tested in bioassays for rare antigen-specific T cells. The automated method succeeded at identifying 79% of patients with the rare PBLs of interest as compared with Ficoll's uniform failure. We validated improved upfront blood processing and show accurate detection of rare antigen-specific lymphocytes. Improving, automating and standardizing lymphocyte detections from whole blood may facilitate development of new cell-based biomarkers for human diseases. Improved upfront blood processes may lead to broad improvements in monitoring early trial outcome measurements in human clinical trials.

Markers for blood-brain barrier integrity

DEFF Research Database (Denmark)

Saunders, Norman R; Dziegielewska, Katarzyna M; Møllgård, Kjeld

2015-01-01

In recent years there has been a resurgence of interest in brain barriers and various roles their intrinsic mechanisms may play in neurological disorders. Such studies require suitable models and markers to demonstrate integrity and functional changes at the interfaces between blood, brain......, and cerebrospinal fluid. Studies of brain barrier mechanisms and measurements of plasma volume using dyes have a long-standing history, dating back to the late nineteenth-century. Their use in blood-brain barrier studies continues in spite of their known serious limitations in in vivo applications. These were well...... known when first introduced, but seem to have been forgotten since. Understanding these limitations is important because Evans blue is still the most commonly used marker of brain barrier integrity and those using it seem oblivious to problems arising from its in vivo application. The introduction...

Lithium determination in whole blood by flame atomic emission spectrometry

International Nuclear Information System (INIS)

Rahman, S.; Khalid, N.; Nasimullah; Iqbal, M.Z.

2003-01-01

A simple and rapid method for the determination of lithium in whole blood using Flame atomic emission spectrometry is described. No sample preparation was required apart from dilution with 0.02 N HNO/sub 3/. The reliability of the method was determined by analyzing Standard Reference Material (SRM) under identical experimental conditions and comparing the determined lithium concentration with the reported value. These were in good agreement with each other. The determined range of lithium in the whole blood of fifty-six healthy adult volunteers (28 males and 28 females) were 13.1 - 47.8 mg L-1. The determined average concentration of lithium in whole blood was compared with the reported values of other countries. The data was statistically analyzed with respect to sex and different age groups. (author)

[Pre-analytical stability before centrifugation of 7 biochemical analytes in whole blood].

Science.gov (United States)

Perrier-Cornet, Andreas; Moineau, Marie-Pierre; Narbonne, Valérie; Plee-Gautier, Emmanuelle; Le Saos, Fabienne; Carre, Jean-Luc

2015-01-01

The pre-analytical stability of 7 biochemical parameters (parathyroid hormone -PTH-, vitamins A, C E and D, 1,25-dihydroxyvitamin D and insulin) at +4 °C, was studied on whole blood samples before centrifugation. The impact of freezing at -20°C was also analyzed/performed for PTH and vitamin D. The differences in the results of assays for whole blood samples, being kept for different times between sampling time and analysis, from 9 healthy adults, were compaired by using a Student t test. The 7 analytes investigated remained stable up to 4 hours at +4°C in whole blood. This study showed that it is possible to accept uncentrifuged whole blood specimens kept at +4°C before analysis. PTH is affected by freezing whereas vitamin D is not.

Concentration and correlations of perfluoroalkyl substances in whole blood among subjects from three different geographical areas in Korea

Energy Technology Data Exchange (ETDEWEB)

Cho, Chon Rae; Lam, Nguyen Hoang [College of Fisheries and Ocean Sciences, Chonnam National University, Yeosu 550-749 (Korea, Republic of); Cho, Byung Mann [Department of Preventive Medicine and Occupational Medicine, School of Medicine, Pusan National University, Yangsan 626-770 (Korea, Republic of); Kannan, Kurunthachalam [Wadsworth Center, New York State Department of Health and Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Empire State Plaza PO Box 509, Albany, NY 12201-0509 (United States); Cho, Hyeon Seo, E-mail: hscho@jnu.ac.kr [College of Fisheries and Ocean Sciences, Chonnam National University, Yeosu 550-749 (Korea, Republic of)

2015-04-15

Toxicity and persistence of perfluorinated alkyl substances (PFASs) in human have raised considerable concern and several biomonitoring studies throughout the world reported the widespread occurrence of these compounds in human tissues. However, information regarding influence of geographic, lifestyle and demographic factor on PFAS levels in human blood tissues is limited. In this study, whole blood samples collected in 2006–2007 from 319 donors from suburban Seoul (Suwon and Yongin), Busan and Yeosu in Korea were analyzed for perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonamide (PFOSA). Blood donors classified into seven age groups with ages ranging from 8 to 82 years, and different lifestyles and socio-economic status. PFOS (median = 4.15 ng/mL) was found at the highest concentration with a maximum concentration of 59.1 ng/mL. The concentrations of other PFASs were in the decreasing order of; PFOA (median = 1.30 ng/mL) > PFNA (median = 0.85 ng/mL) > PFHxS (median = 0.47 ng/mL) > PFOSA (median = 0.12 ng/mL). Geographical differences in the concentrations of five target PFASs were found. Significant positive relationships between PFAS concentrations and the age of the donors were found. Gender-related differences were found in the concentrations of PFOA, PFNA, PFHxS and PFOSA. No association was found between PFAS levels and several lifestyle factors and socio-economic status which included drinking habit, furniture/carpet in an indoor environment and monthly income. Occupation was an important determinant for PFNA and PFHxS concentrations in the whole blood. Except for PFOSA, significant associations were noted between PFASs concentrations and smoking habit. The results of this study provide information for further public health monitoring and safety management for PFASs in Korea. - Highlights: • Significant geographical differences in PFAS levels in whole

Concentration and correlations of perfluoroalkyl substances in whole blood among subjects from three different geographical areas in Korea

International Nuclear Information System (INIS)

Cho, Chon Rae; Lam, Nguyen Hoang; Cho, Byung Mann; Kannan, Kurunthachalam; Cho, Hyeon Seo

2015-01-01

Toxicity and persistence of perfluorinated alkyl substances (PFASs) in human have raised considerable concern and several biomonitoring studies throughout the world reported the widespread occurrence of these compounds in human tissues. However, information regarding influence of geographic, lifestyle and demographic factor on PFAS levels in human blood tissues is limited. In this study, whole blood samples collected in 2006–2007 from 319 donors from suburban Seoul (Suwon and Yongin), Busan and Yeosu in Korea were analyzed for perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonamide (PFOSA). Blood donors classified into seven age groups with ages ranging from 8 to 82 years, and different lifestyles and socio-economic status. PFOS (median = 4.15 ng/mL) was found at the highest concentration with a maximum concentration of 59.1 ng/mL. The concentrations of other PFASs were in the decreasing order of; PFOA (median = 1.30 ng/mL) > PFNA (median = 0.85 ng/mL) > PFHxS (median = 0.47 ng/mL) > PFOSA (median = 0.12 ng/mL). Geographical differences in the concentrations of five target PFASs were found. Significant positive relationships between PFAS concentrations and the age of the donors were found. Gender-related differences were found in the concentrations of PFOA, PFNA, PFHxS and PFOSA. No association was found between PFAS levels and several lifestyle factors and socio-economic status which included drinking habit, furniture/carpet in an indoor environment and monthly income. Occupation was an important determinant for PFNA and PFHxS concentrations in the whole blood. Except for PFOSA, significant associations were noted between PFASs concentrations and smoking habit. The results of this study provide information for further public health monitoring and safety management for PFASs in Korea. - Highlights: • Significant geographical differences in PFAS levels in whole

Fermionic greybody factors of two and five-dimensional dilatonic black holes

Energy Technology Data Exchange (ETDEWEB)

Becar, Ramon [Universidad Catolica de Temuco, Departamento de Ciencias Matematicas y Fisicas, Temuco (Chile); Gonzalez, P.A. [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Vasquez, Yerko [Universidad de La Serena, Departamento de Fisica, Facultad de Ciencias, La Serena (Chile)

2014-08-15

We study fermionic perturbations in the background of a two and five-dimensional dilatonic black holes. Then, we compute the reflection and transmission coefficients and the absorption cross section for fermionic fields, and we show numerically that the absorption cross section vanishes in the low and high frequency limit. Also we find that beyond a certain value of the horizon radius r{sub 0} the absorption cross section for five-dimensional dilatonic black hole is constant. Besides, we have find that the absorption cross section decreases for higher angular momentum, and it decreases when the mass of the fermionic field increases. (orig.)

Effects of intracarotid ioxaglate on the normal blood-brain barrier

International Nuclear Information System (INIS)

Wilcox, J.; Sage, M.R.

1985-01-01

Using two different models, the effect on the blood-brain barrier of intracarotid injections of sodium/meglumine ioxaglate at similar iodine concentrations (280 mgI/ml) was investigated. In both models the degree of blood-brain barrier damage was assessed visually using Evans' Blue stain. Quantitative assessment of blood-brain barrier disruption was made by contrast enhancement as measured by CT of the dog brain, and by 99m Tc-pertechnetate uptake by the brain in the rabbit model. No Evans' Blue staining was observed in any study using the canine/CT model. Slight staining was observed in two studies with ioxaglate using the rabbit/pertechnetate model. Statistical analysis of results from the canine/CT model did not detect any damage to the blood-brain barrier with either ioxaglate or saline control studies (P>0.1). However, in the rabbit/pertechnetate model a slight increase in disruption of the blood-brain barrier was observed with ioxaglate compared with control studies, but this was only significant at the 0.1 level. The results suggest that the rabbit/pertechnetate model is a more sensitive measure of blood-brain barrier disruption than the canine/CT model. This study also demonstrates that blood-brain barrier disruption following intracarotid injection of ioxaglate is minimal. (orig.)

Whole-brain activity mapping onto a zebrafish brain atlas.

Science.gov (United States)

Randlett, Owen; Wee, Caroline L; Naumann, Eva A; Nnaemeka, Onyeka; Schoppik, David; Fitzgerald, James E; Portugues, Ruben; Lacoste, Alix M B; Riegler, Clemens; Engert, Florian; Schier, Alexander F

2015-11-01

In order to localize the neural circuits involved in generating behaviors, it is necessary to assign activity onto anatomical maps of the nervous system. Using brain registration across hundreds of larval zebrafish, we have built an expandable open-source atlas containing molecular labels and definitions of anatomical regions, the Z-Brain. Using this platform and immunohistochemical detection of phosphorylated extracellular signal–regulated kinase (ERK) as a readout of neural activity, we have developed a system to create and contextualize whole-brain maps of stimulus- and behavior-dependent neural activity. This mitogen-activated protein kinase (MAP)-mapping assay is technically simple, and data analysis is completely automated. Because MAP-mapping is performed on freely swimming fish, it is applicable to studies of nearly any stimulus or behavior. Here we demonstrate our high-throughput approach using pharmacological, visual and noxious stimuli, as well as hunting and feeding. The resultant maps outline hundreds of areas associated with behaviors.

Whole-brain activity mapping onto a zebrafish brain atlas

Science.gov (United States)

Randlett, Owen; Wee, Caroline L.; Naumann, Eva A.; Nnaemeka, Onyeka; Schoppik, David; Fitzgerald, James E.; Portugues, Ruben; Lacoste, Alix M.B.; Riegler, Clemens; Engert, Florian; Schier, Alexander F.

2015-01-01

In order to localize the neural circuits involved in generating behaviors, it is necessary to assign activity onto anatomical maps of the nervous system. Using brain registration across hundreds of larval zebrafish, we have built an expandable open source atlas containing molecular labels and anatomical region definitions, the Z-Brain. Using this platform and immunohistochemical detection of phosphorylated-Extracellular signal-regulated kinase (ERK/MAPK) as a readout of neural activity, we have developed a system to create and contextualize whole brain maps of stimulus- and behavior-dependent neural activity. This MAP-Mapping (Mitogen Activated Protein kinase – Mapping) assay is technically simple, fast, inexpensive, and data analysis is completely automated. Since MAP-Mapping is performed on fish that are freely swimming, it is applicable to nearly any stimulus or behavior. We demonstrate the utility of our high-throughput approach using hunting/feeding, pharmacological, visual and noxious stimuli. The resultant maps outline hundreds of areas associated with behaviors. PMID:26778924

The fibrinolytic system facilitates tumor cell migration across the blood-brain barrier in experimental melanoma brain metastasis

International Nuclear Information System (INIS)

Perides, George; Zhuge, Yuzheng; Lin, Tina; Stins, Monique F; Bronson, Roderick T; Wu, Julian K

2006-01-01

Patients with metastatic tumors to the brain have a very poor prognosis. Increased metastatic potential has been associated with the fibrinolytic system. We investigated the role of the fibrinolytic enzyme plasmin in tumor cell migration across brain endothelial cells and growth of brain metastases in an experimental metastatic melanoma model. Metastatic tumors to the brain were established by direct injection into the striatum or by intracarotid injection of B16F10 mouse melanoma cells in C57Bl mice. The role of plasminogen in the ability of human melanoma cells to cross a human blood-brain barrier model was studied on a transwell system. Wild type mice treated with the plasmin inhibitor epsilon-aminocaproic acid (EACA) and plg -/- mice developed smaller tumors and survived longer than untreated wild type mice. Tumors metastasized to the brain of wild type mice treated with EACA and plg -/- less efficiently than in untreated wild type mice. No difference was observed in the tumor growth in any of the three groups of mice. Human melanoma cells were able to cross the human blood-brain barrier model in a plasmin dependent manner. Plasmin facilitates the development of tumor metastasis to the brain. Inhibition of the fibrinolytic system could be considered as means to prevent tumor metastasis to the brain

Whole-brain atrophy rate and cognitive decline: longitudinal MR study of memory clinic patients

NARCIS (Netherlands)

Sluimer, J.D.; van der Flier, W.M.; Karas, G.B.; Fox, N.C.; Scheltens, P.; Barkhof, F.; Vrenken, H.

2008-01-01

Purpose: To prospectively determine whole-brain atrophy rate in mild cognitive impairment (MCI) and Alzheimer disease (AD) and its association with cognitive decline, and investigate the risk of progression to dementia in initially non-demented patients given baseline brain volume and whole-brain

Radiosurgery for brain metastases: is whole brain radiotherapy necessary?

International Nuclear Information System (INIS)

Sneed, Penny K.; Lamborn, Kathleen R.; Forstner, Julie M.; McDermott, Michael W.; Chang, Susan; Park, Elaine; Gutin, Philip H.; Phillips, Theodore L.; Wara, William M.; Larson, David A.

1999-01-01

Purpose: Because whole brain radiotherapy (WBRT) may cause dementia in long-term survivors, selected patients with brain metastases may benefit from initial treatment with radiosurgery (RS) alone reserving WBRT for salvage as needed. We reviewed results of RS ± WBRT in patients with newly diagnosed brain metastasis to provide background for a prospective trial. Methods and Materials: Patients with single or multiple brain metastases managed initially with RS alone vs. RS + WBRT (62 vs. 43 patients) from 1991 through February 1997 were retrospectively reviewed. The use of upfront WBRT depended on physician preference and referral patterns. Survival, freedom from progression (FFP) endpoints, and brain control allowing for successful salvage therapy were measured from the date of diagnosis of brain metastases. Actuarial curves were estimated using the Kaplan-Meier method. Analyses to adjust for known prognostic factors were performed using the Cox proportional hazards model (CPHM) stratified by primary site. Results: Survival and local FFP were the same for RS alone vs. RS + WBRT (median survival 11.3 vs. 11.1 months and 1-year local FFP by patient 71% vs. 79%, respectively). Brain FFP (scoring new metastases and/or local failure) was significantly worse for RS alone vs. RS + WBRT (28% vs. 69% at 1 year; CPHM adjusted p = 0.03 and hazard ratio = 0.476). However, brain control allowing for successful salvage of a first failure was not significantly different for RS alone vs. RS + WBRT (62% vs. 73% at 1 year; CPHM adjusted p = 0.56). Conclusions: The omission of WBRT in the initial management of patients treated with RS for up to 4 brain metastases does not appear to compromise survival or intracranial control allowing for salvage therapy as indicated. A randomized trial of RS vs. RS + WBRT is needed to assess survival, quality of life, and cost in good-prognosis patients with newly diagnosed brain metastases

Secondary instability and transition in three-dimensional boundary layers

Energy Technology Data Exchange (ETDEWEB)

Stolte, A.; Bertolotti, F.P.; Koch, W. (Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Goettingen (Germany). Inst. fuer Stroemungsmechanik)

1999-01-01

Stationary and traveling crossflow modes are the most prominent disturbances in the highly accelerated three-dimensional flow near the leading edge of a swept wing. Near transition onset, secondary three-dimensional instabilities of high frequency can be observed in such flows. A model flow on the basis of a DLR swept plate experiment allows a detailed study of transition scenarios triggered by crossflow instabilities, since the favorable pressure gradient over the whole plate inhibits instabilities of Tollmien-Schlichting type. In order to shed some light upon the role of the high-frequency secondary instabilities, the saturation characteristics of crossflow vortices in this model flow are investigated using the parabolized stability equations. In contrast to nonlinear equilibrium solutions of steady crossflow vortices, the nonlinear Polarized Stability Equations (PSE) results yield different maximal disturbance amplitudes for different initial amplitudes. (orig./AKF)

Secondary instability and transition in three-dimensional boundary layers

Energy Technology Data Exchange (ETDEWEB)

Stolte, A.; Bertolotti, F.P.; Koch, W. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Goettingen (Germany). Inst. fuer Stroemungsmechanik

1999-12-01

Stationary and traveling crossflow modes are the most prominent disturbances in the highly accelerated three-dimensional flow near the leading edge of a swept wing. Near transition onset, secondary three-dimensional instabilities of high frequency can be observed in such flows. A model flow on the basis of a DLR swept plate experiment allows a detailed study of transition scenarios triggered by crossflow instabilities, since the favorable pressure gradient over the whole plate inhibits instabilities of Tollmien-Schlichting type. In order to shed some light upon the role of the high-frequency secondary instabilities, the saturation characteristics of crossflow vortices in this model flow are investigated using the parabolized stability equations. In contrast to nonlinear equilibrium solutions of steady crossflow vortices, the nonlinear Polarized Stability Equations (PSE) results yield different maximal disturbance amplitudes for different initial amplitudes. (orig./AKF)

Potent innate immune response to pathogenic leptospira in human whole blood.

Directory of Open Access Journals (Sweden)

Marga G A Goris

Full Text Available BACKGROUND: Leptospirosis is caused by pathogenic spirochetes of the genus Leptospira. The bacteria enter the human body via abraded skin or mucous membranes and may disseminate throughout. In general the clinical picture is mild but some patients develop rapidly progressive, severe disease with a high case fatality rate. Not much is known about the innate immune response to leptospires during haematogenous dissemination. Previous work showed that a human THP-1 cell line recognized heat-killed leptospires and leptospiral LPS through TLR2 instead of TLR4. The LPS of virulent leptospires displayed a lower potency to trigger TNF production by THP-1 cells compared to LPS of non-virulent leptospires. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the host response and killing of virulent and non-virulent Leptospira of different serovars by human THP-1 cells, human PBMC's and human whole blood. Virulence of each leptospiral strain was tested in a well accepted standard guinea pig model. Virulent leptospires displayed complement resistance in human serum and whole blood while in-vitro attenuated non-virulent leptospires were rapidly killed in a complement dependent manner. In vitro stimulation of THP-1 and PBMC's with heat-killed and living leptospires showed differential serovar and cell type dependence of cytokine induction. However, at low, physiological, leptospiral dose, living virulent complement resistant strains were consistently more potent in whole blood stimulations than the corresponding non-virulent complement sensitive strains. At higher dose living virulent and non-virulent leptospires were equipotent in whole blood. Inhibition of different TLRs indicated that both TLR2 and TLR4 as well as TLR5 play a role in the whole blood cytokine response to living leptospires. CONCLUSIONS/SIGNIFICANCE: Thus, in a minimally altered system as human whole blood, highly virulent Leptospira are potent inducers of the cytokine response.

Quantum Mechanics and Black Holes in Four-Dimensional String Theory

CERN Document Server

Ellis, Jonathan Richard; Nanopoulos, Dimitri V

1992-01-01

In previous papers we have shown how strings in a two-dimensional target space reconcile quantum mechanics with general relativity, thanks to an infinite set of conserved quantum numbers, ``W-hair'', associated with topological soliton-like states. In this paper we extend these arguments to four dimensions, by considering explicitly the case of string black holes with radial symmetry. The key infinite-dimensional W-symmetry is associated with the $\\frac{SU(1,1)}{U(1)}$ coset structure of the dilaton-graviton sector that is a model-independent feature of spherically symmetric four-dimensional strings. Arguments are also given that the enormous number of string {\\it discrete (topological)} states account for the maintenance of quantum coherence during the (non-thermal) stringy evaporation process, as well as quenching the large Hawking-Bekenstein entropy associated with the black hole. Defining the latter as the measure of the loss of information for an observer at infinity, who - ignoring the higher string qua...

Experimental Evidence for Improved Neuroimaging Interpretation Using Three-Dimensional Graphic Models

Science.gov (United States)

Ruisoto, Pablo; Juanes, Juan Antonio; Contador, Israel; Mayoral, Paula; Prats-Galino, Alberto

2012-01-01

Three-dimensional (3D) or volumetric visualization is a useful resource for learning about the anatomy of the human brain. However, the effectiveness of 3D spatial visualization has not yet been assessed systematically. This report analyzes whether 3D volumetric visualization helps learners to identify and locate subcortical structures more…

In vitro evidence for the brain glutamate efflux hypothesis: brain endothelial cells cocultured with astrocytes display a polarized brain-to-blood transport of glutamate.

Science.gov (United States)

Helms, Hans Christian; Madelung, Rasmus; Waagepetersen, Helle Sønderby; Nielsen, Carsten Uhd; Brodin, Birger

2012-05-01

The concentration of the excitotoxic amino acid, L-glutamate, in brain interstitial fluid is tightly regulated by uptake transporters and metabolism in astrocytes and neurons. The aim of this study was to investigate the possible role of the blood-brain barrier endothelium in brain L-glutamate homeostasis. Transendothelial transport- and accumulation studies of (3) H-L-glutamate, (3) H-L-aspartate, and (3) H-D-aspartate in an electrically tight bovine endothelial/rat astrocyte blood-brain barrier coculture model were performed. After 6 days in culture, the endothelium displayed transendothelial resistance values of 1014 ± 70 Ω cm(2) , and (14) C-D-mannitol permeability values of 0.88 ± 0.13 × 10(-6) cm s(-1) . Unidirectional flux studies showed that L-aspartate and L-glutamate, but not D-aspartate, displayed polarized transport in the brain-to-blood direction, however, all three amino acids accumulated in the cocultures when applied from the abluminal side. The transcellular transport kinetics were characterized with a K(m) of 69 ± 15 μM and a J(max) of 44 ± 3.1 pmol min(-1) cm(-2) for L-aspartate and a K(m) of 138 ± 49 μM and J(max) of 28 ± 3.1 pmol min(-1) cm(-2) for L-glutamate. The EAAT inhibitor, DL-threo-ß-Benzyloxyaspartate, inhibited transendothelial brain-to-blood fluxes of L-glutamate and L-aspartate. Expression of EAAT-1 (Slc1a3), -2 (Slc1a2), and -3 (Slc1a1) mRNA in the endothelial cells was confirmed by conventional PCR and localization of EAAT-1 and -3 in endothelial cells was shown with immunofluorescence. Overall, the findings suggest that the blood-brain barrier itself may participate in regulating brain L-glutamate concentrations. Copyright © 2012 Wiley Periodicals, Inc.

Regional brain glucose metabolism and blood flow in streptozocin-induced diabetic rats

International Nuclear Information System (INIS)

Jakobsen, J.; Nedergaard, M.; Aarslew-Jensen, M.; Diemer, N.H.

1990-01-01

Brain regional glucose metabolism and regional blood flow were measured from autoradiographs by the uptake of [ 3 H]-2-deoxy-D-glucose and [ 14 C]iodoantipyrine in streptozocin-induced diabetic (STZ-D) rats. After 2 days of diabetes, glucose metabolism in the neocortex, basal ganglia, and white matter increased by 34, 37, and 8%, respectively, whereas blood flow was unchanged. After 4 mo, glucose metabolism in the same three regions was decreased by 32, 43, and 60%. This reduction was paralleled by a statistically nonsignificant reduction in blood flow in neocortex and basal ganglia. It is suggested that the decrease of brain glucose metabolism in STZ-D reflects increased ketone body oxidation and reduction of electrochemical work

Whole Brain Thinking : An Educational Alternative for Language Instructors

OpenAIRE

Ogawa,Ruby Toshimi

2008-01-01

Whole brain thinking offers new potentials in providing an educational alternative in teaching English as a Second Language (ESL). Prevailing research has shown that the right and the left sides of the brain function and process information differently according to Nobel Prize Winner Roger Sperry in his split-brain research on epileptics. While acknowledging these physical neurological differences, current research suggesting that in view of traditional teaching methods that rely on left-brai...

Comparison of glucose concentration and glucose absorption from the GI-tract in pigs in whole blood and in plasma

DEFF Research Database (Denmark)

Theil, Peter Kappel; Jørgensen, Henry; Larsen, Torben

2010-01-01

using a biosensitive electrode (Exp. 1) or a standard colourimetric method (Exp. 2). In general, glucose measured in whole blood was 7-11% lower than in plasma at low glucose levels (3.5-5 mM), whereas the methods agreed well at high glucose levels (10-14 mM). Evaluation of the regression lines between......The present investigation was undertaken to compare glucose absorption from the gastro-intestinal tract quantified in either whole blood or plasma using the arterio-venous differences and portal blood flow measurements. Pigs were surgically modified with catheters in the portal vein...... three different diets with similar contents of starch (470-506 g/kg DM). The diets in both studies differed regarding amount and solubility of fibre. Blood samples were collected repeatedly 0-10 h after morning feeding. Glucose was measured in whole blood using a glucometer (Accu-Chek®) and in plasma...

Effects of Nattokinase on Whole Blood Viscosity and Mortality

Directory of Open Access Journals (Sweden)

Melike Cengiz

2011-12-01

Full Text Available Objective: Nattokinase is a serin protease having potent fibrinolytic effect derived from fermentation of boiled soy bean by the use of Basillus Subtilis Natto. The aim of this experimental study is to investigate the effects of intragastric Nattokinase (6 mg/day administration for 7 days prior to formation of sepsis on plasma fibrinogen levels, whole blood viscosity and mortality in rats. Materials and Methods: Intraabdominal sepsis were performed by cecal ligation and puncture in rats supplemented with nattokinase or olive oil for 7 days prior to sepsis formation. Plasma fibrinogen, whole blood viscosity analysis and survival analysis was performed after intraabdominal sepsis formation. Results: Mean blood viscosity of rats was lower in Nattokinase and cecal ligation group at lowest shear rate (p<0.05. However, the differences between groups were not significant at higher shear rates. No difference was found in survival rates and survival times of Nattokinase and cecal ligation and cecal ligation and puncture groups. Conclusion: Our results were unable to show the effects of intragastric nattokinase supplementation prior to sepsis on plasma fibrinogen levels or whole blood viscosity, except low shear rate. Nattokinase did not altered survival in septic rats. (Journal of the Turkish Society Intensive Care 2011; 9: 85-9

Three-dimensional, three-component wall-PIV

Science.gov (United States)

Berthe, André; Kondermann, Daniel; Christensen, Carolyn; Goubergrits, Leonid; Garbe, Christoph; Affeld, Klaus; Kertzscher, Ulrich

2010-06-01

This paper describes a new time-resolved three-dimensional, three-component (3D-3C) measurement technique called wall-PIV. It was developed to assess near wall flow fields and shear rates near non-planar surfaces. The method is based on light absorption according to Beer-Lambert’s law. The fluid containing a molecular dye and seeded with buoyant particles is illuminated by a monochromatic, diffuse light. Due to the dye, the depth of view is limited to the near wall layer. The three-dimensional particle positions can be reconstructed by the intensities of the particle’s projection on an image sensor. The flow estimation is performed by a new algorithm, based on learned particle trajectories. Possible sources of measurement errors related to the wall-PIV technique are analyzed. The accuracy analysis was based on single particle experiments and a three-dimensional artificial data set simulating a rotating sphere.

Electromembrane extraction of stimulating drugs from undiluted whole blood

DEFF Research Database (Denmark)

Jamt, Ragnhild Elén Gjulem; Gjelstad, Astrid; Eibak, Lars Erik Eng

2012-01-01

For the first time, electromembrane extraction (EME) of six basic drugs of abuse from undiluted whole blood and post mortem blood in a totally stagnant system is reported. Cathinone, methamphetamine, 3,4-methylenedioxy-amphetamine (MDA), 3,4-methylenedioxy-methamphet-amine (MDMA), ketamine and 2...

Whole blood microculture assay of human lymphocyte function.

Science.gov (United States)

Pauly, J L; Han, T

1976-11-01

A whole blood microculture assay is described for measuring lymphocyte reactivity to mitogenic and antigenic stimulants. This assay employs heparinized whole blood, serum-free culture medium, microtiter plates, and a Multiple Automated Sample Harvester (MASH). When this assay is compared to other leukocyte assays, its major advantages include (1) the utilization of fewer lymphocytes per microculture, thuus reducing the amount of blood required per test while increasing the number of test agents and replicate cultures which can be employed in any given experiment; (2) the conservation of mitogens, antigens, drugs, enzymes, hormones, lymphokines, and other test agents, some of which are either expensive of difficult to prepare in large quantities; (3) the elimination of lymphocyte isolation and purification procedures which may disrupt the relative proportion of T cells, B cells and antigen-processing cells; and (4) the application of an automated harvester which simplifies and expedites procedures required for processing cells for liquid scintillation counting.

Three-dimensional structure of brain tissue at submicrometer resolution

Energy Technology Data Exchange (ETDEWEB)

Saiga, Rino; Mizutani, Ryuta, E-mail: ryuta@tokai-u.jp [Department of Applied Biochemistry, Tokai University, Hiratsuka, Kanagawa 259-1292 (Japan); Inomoto, Chie; Takekoshi, Susumu; Nakamura, Naoya; Tsuboi, Akio; Osawa, Motoki [Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Arai, Makoto; Oshima, Kenichi; Itokawa, Masanari [Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-8506 (Japan); Uesugi, Kentaro; Takeuchi, Akihisa; Terada, Yasuko; Suzuki, Yoshio [Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), Sayo, Hyogo 679-5198 (Japan)

2016-01-28

Biological objects are composed of submicrometer structures such as cells and organelles that are essential for their functions. Here, we report on three-dimensional X-ray visualization of cells and organelles at resolutions up to 100 nm by imaging microtomography (micro-CT) equipped with Fresnel zone plate optics. Human cerebral tissue, fruit fly cephalic ganglia, and Escherichia coli bacteria labeled with high atomic-number elements were embedded in epoxy resin and subjected to X-ray microtomography at the BL37XU and BL47XU beamlines of the SPring-8 synchrotron radiation facility. The obtained results indicated that soft tissue structures can be visualized with the imaging microtomography.

A micro-fluidic study of whole blood behaviour on PMMA topographical nanostructures

Directory of Open Access Journals (Sweden)

Tsud Nataliya

2008-02-01

Full Text Available Abstract Background Polymers are attractive materials for both biomedical engineering and cardiovascular applications. Although nano-topography has been found to influence cell behaviour, no established method exists to understand and evaluate the effects of nano-topography on polymer-blood interaction. Results We optimized a micro-fluidic set-up to study the interaction of whole blood with nano-structured polymer surfaces under flow conditions. Micro-fluidic chips were coated with polymethylmethacrylate films and structured by polymer demixing. Surface feature size varied from 40 nm to 400 nm and feature height from 5 nm to 50 nm. Whole blood flow rate through the micro-fluidic channels, platelet adhesion and von Willebrand factor and fibrinogen adsorption onto the structured polymer films were investigated. Whole blood flow rate through the micro-fluidic channels was found to decrease with increasing average surface feature size. Adhesion and spreading of platelets from whole blood and von Willebrand factor adsorption from platelet poor plasma were enhanced on the structured surfaces with larger feature, while fibrinogen adsorption followed the opposite trend. Conclusion We investigated whole blood behaviour and plasma protein adsorption on nano-structured polymer materials under flow conditions using a micro-fluidic set-up. We speculate that surface nano-topography of polymer films influences primarily plasma protein adsorption, which results in the control of platelet adhesion and thrombus formation.

Surgical Resection Followed by Whole Brain Radiotherapy Versus Whole Brain Radiotherapy Alone for Single Brain Metastasis

International Nuclear Information System (INIS)

Rades, Dirk; Kieckebusch, Susanne; Haatanen, Tiina; Lohynska, Radka; Dunst, Juergen; Schild, Steven E.

2008-01-01

Purpose: To compare the outcome of surgical resection followed by whole brain radiotherapy (WBRT) with WBRT alone in patients treated for single brain metastasis. Methods and Materials: The data from 195 patients with single brain metastases were retrospectively evaluated. Of the 195 patients, 99 underwent resection of the metastasis followed by WBRT and 96 underwent WBRT alone. Seven additional potential prognostic factors were investigated: age, gender, Eastern Cooperative Oncology Group performance score, tumor type, interval between initial tumor diagnosis and WBRT, extracranial metastases, and recursive partitioning analysis class. Both treatment groups were well balanced for these factors. Results: On multivariate analysis, improved survival was associated with resection (relative risk [RR], 1.20; 95% confidence interval [CI], 1.11-1.31; p < 0.001), lower recursive partitioning analysis class (RR, 1.58; 95% CI, 1.22-2.06; p < 0.001), age ≤61 years (RR, 1.79; 95% CI, 1.23-2.61; p = 0.002), Eastern Cooperative Oncology Group performance score of 0-1 (RR, 2.47; 95% CI, 1.70-3.59; p < 0.001), and the absence of extracranial metastases (RR, 1.99; 95% CI, 1.41-2.79; p < 0.001). Improved local control was associated with resection (RR, 1.25; 95% CI, 1.11-1.41; p < 0.001) and age ≤61 years (RR, 1.77; 95% CI, 1.09-2.88; p = 0.020). Improved brain control distant from the original site was associated with lower recursive partitioning analysis class (RR, 1.65; 95% CI, 1.03-2.69; p < 0.035), age ≤61 years (RR, 1.81; 95% CI, 1.12-2.96; p = 0.016), and the absence of extracranial metastases (RR, 2.42; 95% CI, 1.52-3.88; p < 0.001). Improved control within the entire brain was associated with surgery (RR, 1.24; 95% CI, 1.12-1.38; p < 0.001) and age ≤61 years (RR, 1.83; 95% CI, 1.21-2.77; p = 0.004). Conclusion: In patients with a single brain metastasis, the addition of resection to WBRT improved survival, local control at the original metastatic site, and control

Effects of GSM modulated radio-frequency electromagnetic radiation on permeability of blood-brain barrier in male & female rats.

Science.gov (United States)

Sırav, Bahriye; Seyhan, Nesrin

2016-09-01

With the increased use of mobile phones, their biological and health effects have become more important. Usage of mobile phones near the head increases the possibility of effects on brain tissue. This study was designed to investigate the possible effects of pulse modulated 900MHz and 1800MHz radio-frequency radiation on the permeability of blood-brain barrier of rats. Study was performed with 6 groups of young adult male and female wistar albino rats. The permeability of blood-brain barrier to intravenously injected evans blue dye was quantitatively examined for both control and radio-frequency radiarion exposed groups. For male groups; Evans blue content in the whole brain was found to be 0.08±0.01mg% in the control, 0.13±0.03mg% in 900MHz exposed and 0.26±0.05mg% in 1800MHz exposed animals. In both male radio-frequency radiation exposed groups, the permeability of blood-brain barrier found to be increased with respect to the controls (pradiation exposure was found more effective on the male animals (p0.01). However 900MHz pulse modulated radio-frequency exposure was found effective on the permeability of blood-brain barrier of female animals. Results have shown that 20min pulse modulated radio-frequency radiation exposure of 900MHz and 1800MHz induces an effect and increases the permeability of blood-brain barrier of male rats. For females, 900MHz was found effective and it could be concluded that this result may due to the physiological differences between female and male animals. The results of this study suggest that mobile phone radation could lead to increase the permeability of blood-brain barrier under non-thermal exposure levels. More studies are needed to demonstrate the mechanisms of that breakdown. Copyright © 2015 Elsevier B.V. All rights reserved.

Glial and neuronal control of brain blood flow

DEFF Research Database (Denmark)

Attwell, David; Buchan, Alastair M; Charpak, Serge

2010-01-01

Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now...... in our understanding of cerebral blood flow control have important implications for the development of new therapeutic approaches....

High temporal resolution magnetic resonance imaging: development of a parallel three dimensional acquisition method for functional neuroimaging

International Nuclear Information System (INIS)

Rabrait, C.

2007-11-01

Echo Planar Imaging is widely used to perform data acquisition in functional neuroimaging. This sequence allows the acquisition of a set of about 30 slices, covering the whole brain, at a spatial resolution ranging from 2 to 4 mm, and a temporal resolution ranging from 1 to 2 s. It is thus well adapted to the mapping of activated brain areas but does not allow precise study of the brain dynamics. Moreover, temporal interpolation is needed in order to correct for inter-slices delays and 2-dimensional acquisition is subject to vascular in flow artifacts. To improve the estimation of the hemodynamic response functions associated with activation, this thesis aimed at developing a 3-dimensional high temporal resolution acquisition method. To do so, Echo Volume Imaging was combined with reduced field-of-view acquisition and parallel imaging. Indeed, E.V.I. allows the acquisition of a whole volume in Fourier space following a single excitation, but it requires very long echo trains. Parallel imaging and field-of-view reduction are used to reduce the echo train durations by a factor of 4, which allows the acquisition of a 3-dimensional brain volume with limited susceptibility-induced distortions and signal losses, in 200 ms. All imaging parameters have been optimized in order to reduce echo train durations and to maximize S.N.R., so that cerebral activation can be detected with a high level of confidence. Robust detection of brain activation was demonstrated with both visual and auditory paradigms. High temporal resolution hemodynamic response functions could be estimated through selective averaging of the response to the different trials of the stimulation. To further improve S.N.R., the matrix inversions required in parallel reconstruction were regularized, and the impact of the level of regularization on activation detection was investigated. Eventually, potential applications of parallel E.V.I. such as the study of non-stationary effects in the B.O.L.D. response

Microfabrication and Test of a Three-Dimensional Polymer Hydro-focusing Unit for Flow Cytometry Applications

Science.gov (United States)

Yang, Ren; Feeback, Daniel L.; Wang, Wan-Jun

2005-01-01

This paper details a novel three-dimensional (3D) hydro-focusing micro cell sorter for micro flow cytometry applications. The unit was microfabricated by means of SU-8 3D lithography. The 3D microstructure for coaxial sheathing was designed, microfabricated, and tested. Three-dimensional hydrofocusing capability was demonstrated with an experiment to sort labeled tanned sheep erythrocytes (red blood cells). This polymer hydro-focusing microstructure is easily microfabricated and integrated with other polymer microfluidic structures. Keywords: SU-8, three-dimensional hydro-focusing, microfluidic, microchannel, cytometer

Three-dimensional Ca2+ imaging advances understanding of astrocyte biology.

Science.gov (United States)

Bindocci, Erika; Savtchouk, Iaroslav; Liaudet, Nicolas; Becker, Denise; Carriero, Giovanni; Volterra, Andrea

2017-05-19

Astrocyte communication is typically studied by two-dimensional calcium ion (Ca 2+ ) imaging, but this method has not yielded conclusive data on the role of astrocytes in synaptic and vascular function. We developed a three-dimensional two-photon imaging approach and studied Ca 2+ dynamics in entire astrocyte volumes, including during axon-astrocyte interactions. In both awake mice and brain slices, we found that Ca 2+ activity in an individual astrocyte is scattered throughout the cell, largely compartmented between regions, preponderantly local within regions, and heterogeneously distributed regionally and locally. Processes and endfeet displayed frequent fast activity, whereas the soma was infrequently active. In awake mice, activity was higher than in brain slices, particularly in endfeet and processes, and displayed occasional multifocal cellwide events. Astrocytes responded locally to minimal axonal firing with time-correlated Ca 2+ spots. Copyright © 2017, American Association for the Advancement of Science.

Blood-brain transfer of Pittsburgh compound B in humans

DEFF Research Database (Denmark)

Gjedde, Albert; Aanerud, Joel; Braendgaard, Hans

2013-01-01

-brain barrier is held to be high but the permeability-surface area product and extraction fractions in patients or healthy volunteers are not known. We used PET to determine the clearance associated with the unidrectional blood-brain transfer of [(11)C]PiB and the corresponding cerebral blood flow rates...... with the observation that numerically, but insignificantly, unidirectional blood-brain clearances are lower and extraction fractions higher in the patients. The evidence of unchanged permeability-surface area products in the patients implies that blood flow changes can be deduced from the unidirectional blood......In the labeled form, the Pittsburgh compound B (2-(4'-{N-methyl-[(11)C]}methyl-aminophenyl)-6-hydroxy-benzothiazole, [(11)C]PiB), is used as a biomarker for positron emission tomography (PET) of brain β-amyloid deposition in Alzheimer's disease (AD). The permeability of [(11)C]PiB in the blood...

Dietary Virgin Olive Oil Reduces Blood Brain Barrier Permeability, Brain Edema, and Brain Injury in Rats Subjected to Ischemia-Reperfusion

Directory of Open Access Journals (Sweden)

Fatemeh Mohagheghi

2010-01-01

Full Text Available Recent studies suggest that dietary virgin olive oil (VOO reduces hypoxia-reoxygenation injury in rat brain slices. We sought to extend these observations in an in vivo study of rat cerebral ischemia-reperfusion injury. Four groups, each consisting of 18 Wistar rats, were studied. One group (control received saline, while three treatment groups received oral VOO (0.25, 0.5, and 0.75 mL/kg/day, respectively. After 30 days, blood lipid profiles were determined, before a 60-min period of middle cerebral artery occlusion (MCAO. After 24-h reperfusion, neurological deficit scores, infarct volume, brain edema, and blood brain barrier permeability were each assessed in subgroups of six animals drawn from each main group. VOO reduced the LDL/HDL ratio in doses of 0.25, 0.5, and 0.75 mL/kg/day in comparison to the control group (p < 0.05, and offered cerebroprotection from ischemia-reperfusion. For controls vs. doses of 0.25 vs. 0.5 vs. 0.75 mL/kg/day, attenuated corrected infarct volumes were 207.82 ± 34.29 vs. 206.41 ± 26.23 vs. 124.21 ± 14.73 vs. 108.46 ± 31.63 mm3; brain water content of the infarcted hemisphere was 82 ±± 0.25 vs. 81.5 ± 0.56 vs. 80.5 ± 0.22 vs. 80.5 ± 0.34%; and blood brain barrier permeability of the infarcted hemisphere was 11.31 ± 2.67 vs. 9.21 ± 2.28 vs. 5.83 ± 1.6 vs. 4.43 ± 0.93 µg/g tissue (p < 0.05 for measures in doses 0.5 and 0.75 mL/kg/day vs. controls. Oral administration of VOO reduces infarct volume, brain edema, blood brain barrier permeability, and improves neurologic deficit scores after transient MCAO in rats.

Glial and neuronal control of brain blood flow