339 research outputs found
Handbook for Efficiently Quantifying Robustness of Magic
The nonstabilizerness, or magic, is an essential quantum resource to perform
universal quantum computation. Robustness of magic (RoM) in particular
characterizes the degree of usefulness of a given quantum state for
non-Clifford operation. While the mathematical formalism of RoM can be given in
a concise manner, it is extremely challenging to determine the RoM in practice,
since it involves superexponentially many pure stabilizer states. In this work,
we present efficient novel algorithms to compute the RoM. The crucial technique
is a subroutine that achieves the remarkable features in calculation of
overlaps between pure stabilizer states: (i) the time complexity per each
stabilizer is reduced exponentially, (ii) the space complexity is reduced
superexponentially. Based on this subroutine, we present algorithms to compute
the RoM for arbitrary states up to qubits on a laptop, while brute-force
methods require a memory size of 86 TiB. As a byproduct, the proposed
subroutine allows us to simulate the stabilizer fidelity up to qubits,
for which naive methods require memory size of 86 PiB so that any
state-of-the-art classical computer cannot execute the computation. We further
propose novel algorithms that utilize the preknowledge on the structure of
target quantum state such as the permutation symmetry of disentanglement, and
numerically demonstrate our state-of-the-art results for copies of magic states
and partially disentangled quantum states. The series of algorithms constitute
a comprehensive ``handbook'' to scale up the computation of the RoM, and we
envision that the proposed technique applies to the computation of other
quantum resource measures as well.Comment: 16+12 pages, 8+1 figure
A generalisation of the method of regression calibration and comparison with Bayesian and frequentist model averaging methods
For many cancer sites low-dose risks are not known and must be extrapolated
from those observed in groups exposed at much higher levels of dose.
Measurement error can substantially alter the dose-response shape and hence the
extrapolated risk. Recently, there has been considerable attention paid to
methods of dealing with shared errors, which are particularly important in
occupational and environmental settings. In this paper we test Bayesian model
averaging (BMA) and frequentist model averaging (FMA) methods, the first of
these similar to the so-called Bayesian two-dimensional Monte Carlo (2DMC)
method, and both fairly recently proposed, against a very newly proposed
modification of the regression calibration method, the extended regression
calibration (ERC) method. The quasi-2DMC+BMA method performs well when a linear
model is assumed, but poorly when a linear-quadratic model is assumed. FMA
performs as well as quasi-2DMC+BMA when a linear model is assumed, and
generally much better with a linear-quadratic model, although the coverage
probability for the quadratic coefficient is uniformly too high. ERC yields
coverage probabilities that are too low when shared and unshared Berkson errors
are both large (50%), although otherwise it performs well, and coverage is
generally better than the quasi-2DMC+BMA or FMA methods, particularly for the
linear-quadratic model. The bias of predicted relative risk at a variety of
doses is generally smallest for ERC, and largest for quasi-2DMC+BMA and FMA,
with standard regression calibration and Monte Carlo maximum likelihood
exhibiting bias in predicted relative risk generally somewhat intermediate
between ERC and the other two methods. In general ERC performs best in the
scenarios presented, and should be the method of choice in situations where
there may be substantial shared error, or suspected curvature in the dose
response.Comment: 5 Tables. Fortran code supplied externall
Microdosimetric Modeling of Biological Effectiveness for Boron Neutron Capture Therapy Considering Intra- and Intercellular Heterogeneity in 10B Distribution
We here propose a new model for estimating the biological effectiveness for boron neutron capture therapy (BNCT) considering intra- and intercellular heterogeneity in 10B distribution. The new model was developed from our previously established stochastic microdosimetric kinetic model that determines the surviving fraction of cells irradiated with any radiations. In the model, the probability density of the absorbed doses in microscopic scales is the fundamental physical index for characterizing the radiation fields. A new computational method was established to determine the probability density for application to BNCT using the Particle and Heavy Ion Transport code System PHITS. The parameters used in the model were determined from the measured surviving fraction of tumor cells administrated with two kinds of 10B compounds. The model quantitatively highlighted the indispensable need to consider the synergetic effect and the dose dependence of the biological effectiveness in the estimate of the therapeutic effect of BNCT. The model can predict the biological effectiveness of newly developed 10B compounds based on their intra- and intercellular distributions, and thus, it can play important roles not only in treatment planning but also in drug discovery research for future BNCT
Rab7-Mediated Endocytosis Establishes Patterning of Wnt Activity through Inactivation of Dkk Antagonism
Endocytosis has been proposed to modulate cell signaling activities. However, the role of endocytosis in embryogenesis, which requires coordination of multiple signaling inputs, has remained less understood. We previously showed that mouse embryos lacking a small guanosine triphosphate (GTP)-binding protein Rab7 implicated in endocytic flow are defective in gastrulation. Here, we investigate how subcellular defects associated with Rab7 deficiency are related to the observed developmental defects. Rab7-deficient embryos fail to organize mesodermal tissues due to defects in Wnt-β-catenin signaling. Visceral endoderm (VE)-specific ablation of Rab7 results in patterning defects similar to systemic Rab7 deletion. Rab7 mutants accumulate the Wnt antagonist Dkk1 in the extracellular space and in intracellular compartments throughout the VE epithelium. These data indicate that Rab7-dependent endocytosis regulates the concentration and availability of extracellular Dkk1, thereby relieving the epiblast of antagonism. This intercellular mechanism therefore organizes distinct spatiotemporal patterns of canonical Wnt activity during the peri-gastrulation stages of embryonic development
Proliferation and cell death of human glioblastoma cells after carbon-ion beam exposure: Morphologic and morphometric analyses
Histological analyses of glioblastoma cells after carbon-ion exposure are still limited and ultrastructural characteristics have not been investigated in detail. Here we report the results of morphological and morphometric analyses of a human glioblastoma cell line, CGNH-89, after ionizing radiation to characterize the effect of a carbon-beam on glioblastoma cells. Using CGNH-89 cells exposed to 0–10 Gy of X-ray (140kVp) or carbon-ions (18.3 MeV/nucleon, LET = 108 keV/μm), we performed conventional histology and immunocytochemistry with MIB-1 antibody, transmission electron microscopy, and computer-assisted, nuclear size measurements. CGNH-89 cells with a G to A transition in codon 280 in exon 8 of the TP53 gene had nuclei with pleomorphism, marked nuclear atypia and brisk mitotic activity. After carbon-ion and X-ray exposure, living cells showed decreased cell number, nuclear condensation, increased atypical mitotic figures, and a tendency of cytoplasmic enlargement at the level of light microscopy. The deviation of the nuclear area size increased during 48 hours after irradiation, while the small cell fraction increased in 336 hours. In glioblastoma cells of the control, 5 Gy carbon-beam, and 10 Gy carbon-beam, and MIB-1 labeling index decreased in 24 hours (12%, 11%, 7%, respectively) but increased in 48 hours (10%, 20%, 21%, respectively). Ultrastructurally, cellular enlargement seemed to depend on vacuolation, swelling of mitochondria, and increase of cellular organelles, such as the cytoskeleton and secondary lysosome. We could not observe apoptotic bodies in the CGNH-89 cells under any conditions. We conclude that carbon-ion irradiation induced cell death and senescence in a glioblastoma cell line with mutant TP53. Our results indicated that the increase of large cells with enlarged and bizarre nuclei, swollen mitochondria, and secondary lysosome occurred in glioblastoma cells after carbon-beam exposure.学位記番号:医博甲1096, 学位の種類:博士(医), 学位授与年月日:平成20年3月25
Subthreshold Photocoagulation Using Endpoint Management in the PASCAL® System for Diffuse Diabetic Macular Edema
We evaluated subthreshold photocoagulation using endpoint management (EPM) for the treatment of diabetic macular edema (DME). The study enrolled 10 eyes from 10 patients (6 men and 4 women) with DME. The entry criteria included central macular thickness (CMT) ≥ 300 μm and decimal visual acuity (VA) ≤ 0.5. The primary endpoints were VA (logMAR) and CMT at 6 months follow-up. Secondary endpoints included fundus autofluorescence, macular volume (MV), and macular sensitivity (MS). We used the PASCAL Streamline Yellow® (wavelength, 577 nm) system to perform grid pattern laser photocoagulation at 50% of the threshold (size, 100 μm; duration, 0.015 s; spacing, 0.5; and energy, 4.5–7.8 mJ). At 6 months posttreatment, CMT was significantly decreased, while there were no significant changes in macular sensitivity, mean BCVA (logMAR), or macular volume. Autofluorescence imaging revealed no changes after treatment in 6 of 10 eyes. No eyes exhibited subjective symptoms of scotoma after photocoagulation. Optical coherence tomography showed the complete resolution of macular edema in 4 eyes (40%) after a single treatment; MS was increased in all 4 of these eyes at 6 months posttreatment. In conclusion, subthreshold photocoagulation using EPM is safe and effective for DME treatment and preserves MS. This trial is registered with UMIN000012401
Self Running Droplet: Emergence of Regular Motion from Nonequilibrium Noise
Spontaneous motion of an oil droplet driven by chemical nonequilibricity is
reported. It is shown that the droplet undergoes regular rhythmic motion under
appropriately designed boundary conditions, whereas it exhibits random motion
in an isotropic environment. This study is a novel manifestation on the direct
energy transformation of chemical energy into regular spatial-motion under
isothermal conditions. A simple mathematical equation including noise
reproduces the essential feature of the transition from irregularity into
periodic regular motion. Our results will inspire the theoretical study on the
mechanism of molecular motors in living matter, working under significant
influence of thermal fluctuation.Comment: 4 pages, 4 figure
Inhibition of influenza virus replication in cultured cells by RNA-cleaving DNA enzyme
AbstractInfluenza virus replication has been effectively inhibited by antisense phosphothioate oligonucleotides targeting the AUG initiation codon of PB2 mRNA. We designed RNA-cleaving DNA enzymes from 10-23 catalytic motif to target PB2-AUG initiation codon and measured their RNA-cleaving activity in vitro. Although the RNA-cleaving activity was not optimal under physiological conditions, DNA enzymes inhibited viral replication in cultured cells more effectively than antisense phosphothioate oligonucleotides. Our data indicated that DNA enzymes could be useful for the control of viral infection
Seleção de linhagens fúngicas isoladas de larvas de Simuliidae (Insecta: Diptera) para obtenção de enzimas de interesse industrial na Amazônia: Screening of fungal strains isolated from Simuliidae (Insecta: Diptera) larvae to obtain enzymes of industrial interest in the Amazon
As enzimas estão entre os principais alvos de pesquisas biotecnológicas pelo seu importante papel nos mecanismos celulares e aplicações em processos industriais. O objetivo do estudo foi selecionar linhagens de fungos, isoladas de larvas de Simuliidae, produtoras das enzimas amilase e celulase em meio de cultura sólido. Foram utilizadas 37 linhagens fúngicas cultivadas e armazenadas no INPA. Para o crescimento das diferentes linhagens fúngicas e indução das enzimas foi utilizada solução de Manachini, suplementada de substrato indutor. O cultivo das linhagens foi realizado com inóculo direto de 5x106 esporos/mL, mantidos sob agitação a 140 rpm em temperatura ambiente durante 72 horas. Ao término do período de incubação, as culturas foram filtradas e, em seguida foram adicionados 50µL do filtrado em meio de cultura sólido pela técnica de “Cup plate”. As placas foram envolvidas em papel alumínio e incubadas a 37º C durante 72 horas. Foram utilizadas soluções reveladoras de atividade enzimática, iodo 0,1 Mol/L e solução de vermelho congo a 0,1%), para amilases e celulases, respectivamente. A atividade enzimática foi detectada pelo diâmetro do halo. Do total de 37 linhagens analisadas, 60% apresentaram degradação de substrato tanto para amilase como para celulase e 40% não apresentaram atividade para estas enzimas. As espécies com maior nível de degradação do substrato foram Aspergillus japonicus Saito (halo= 7mm, celulase) e Trichoderma harzianum Rifai (halo= 5mm, amilase). Constata-se assim o potencial desses microrganismos para aplicação industrial, criando novas oportunidades para o desenvolvimento do mercado de enzimas na Amazônia
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