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Genetically and metabolically corrected pluripotent stem cells from patients with mtDNA disease
Clasificación del fruto del durazno en maduros, no maduros y dañados hacia la cosecha automatizada
A partir de la tecnología de visión artificial, específicamente de redes neuronales convolucionales, se propuso una solución para realizar el reconocimiento de frutos de durazno maduros, así como la identificación de frutos dañados. La finalidad es obtener frutos con el nivel de calidad adecuado para su comercialización. Para lograr este propósito, se obtuvieron imágenes de duraznos en un ambiente no controlado. Se recortaron las imágenes digitales hasta obtener el ?rea de interés. Se configuraron tres conjuntos de datos: el primero, de duraznos maduros e inmaduros; el segundo, también de duraznos maduros e inmaduros pero con enfoque en un ?rea textural, y el tercero, de duraznos sanos y da?ados. Se aplicó una red neuronal convolucional, que fue programada en el lenguaje Python, las librerías de Keras y TensorFlow. Durante las pruebas se obtuvo una precisión de 95.31 % a la hora de elegir entre maduros y no maduros. Mientras que al clasificar los duraznos sanos y dañados se obtuvo 92.18 % de precisión. Por último, al clasificar las tres categorías (dañados, inmaduros y maduros), se obtuvo 83.33 % de precisión. Los resultados anteriores indican que con inteligencia artificial embebida en un dispositivo físico se puede hacer la clasificación del fruto del durazno
Ultra-Efficient PrPSc Amplification Highlights Potentialities and Pitfalls of PMCA Technology
In order to investigate the potential of voles to reproduce in vitro the efficiency of prion replication previously observed in vivo, we seeded protein misfolding cyclic amplification (PMCA) reactions with either rodent-adapted Transmissible Spongiform Encephalopathy (TSE) strains or natural TSE isolates. Vole brain homogenates were shown to be a powerful substrate for both homologous or heterologous PMCA, sustaining the efficient amplification of prions from all the prion sources tested. However, after a few serial automated PMCA (saPMCA) rounds, we also observed the appearance of PK-resistant PrPSc in samples containing exclusively unseeded substrate (negative controls), suggesting the possible spontaneous generation of infectious prions during PMCA reactions. As we could not definitively rule out cross-contamination through a posteriori biochemical and biological analyses of de novo generated prions, we decided to replicate the experiments in a different laboratory. Under rigorous prion-free conditions, we did not observe de novo appearance of PrPSc in unseeded samples of M109M and I109I vole substrates, even after many consecutive rounds of saPMCA and working in different PMCA settings. Furthermore, when positive and negative samples were processed together, the appearance of spurious PrPSc in unseeded negative controls suggested that the most likely explanation for the appearance of de novo PrPSc was the occurrence of cross-contamination during saPMCA. Careful analysis of the PMCA process allowed us to identify critical points which are potentially responsible for contamination events. Appropriate technical improvements made it possible to overcome PMCA pitfalls, allowing PrPSc to be reliably amplified up to extremely low dilutions of infected brain homogenate without any false positive results even after many consecutive rounds. Our findings underline the potential drawback of ultrasensitive in vitro prion replication and warn on cautious interpretation when assessing the spontaneous appearance of prions in vitro
The massive model for frustrated spin systems
We study the classical Non Linear
Sigma model which is the continuous low energy effective field theory for
component frustrated spin systems. The functions for the two coupling
constants of this model are calculated around two dimensions at two loop order
in a low temperature expansion. Our study is completed by a large analysis
of the model. The functions for the coupling constants and the mass gap
are calculated in all dimensions between 2 and 4 at order . As a main
result we show that the standard procedure at the basis of the expansion
leads to results that partially contradict those of the weak coupling analysis.
We finally present the procedure that reconciles the weak coupling and large
analysis, giving a consistent picture of the expected scaling of frustrated
magnets.Comment: 55 pages, Late
Epidemiological Surveillance of Birth Defects Compatible with Thalidomide Embryopathy in Brazil
The thalidomide tragedy of the 1960s resulted in thousands of children being born with severe limb reduction defects (LRD), among other malformations. In Brazil, there are still babies born with thalidomide embryopathy (TE) because of leprosy prevalence, availability of thalidomide, and deficiencies in the control of drug dispensation. Our objective was to implement a system of proactive surveillance to identify birth defects compatible with TE. Along one year, newborns with LRD were assessed in the Brazilian hospitals participating in the Latin-American Collaborative Study of Congenital Malformations (ECLAMC). A phenotype of LRD called thalidomide embryopathy phenotype (TEP) was established for surveillance. Children with TEP born between the years 2000–2008 were monitored, and during the 2007–2008 period we clinically investigated in greater detail all cases with TEP (proactive period). The period from 1982 to 1999 was defined as the baseline period for the cumulative sum statistics. The frequency of TEP during the surveillance period, at 3.10/10,000 births (CI 95%: 2.50–3.70), was significantly higher than that observed in the baseline period (1.92/10,000 births; CI 95%: 1.60–2.20), and not uniformly distributed across different Brazilian regions. During the proactive surveillance (2007–2008), two cases of suspected TE were identified, although the two mothers had denied the use of the drug during pregnancy. Our results suggest that TEP has probably increased in recent years, which coincides with the period of greater thalidomide availability. Our proactive surveillance identified two newborns with suspected TE, proving to be a sensitive tool to detect TE. The high frequency of leprosy and the large use of thalidomide reinforce the need for a continuous monitoring of TEP across Brazil
Dynamical structure factors of the magnetization-plateau state in the bond-alternating spin chain with a next-nearest-neighbor interaction
We calculate the dynamical structure factors of the magnetization-plateau
state in the bond-alternating spin chain with a next-nearest-neighbor
interaction. The results show characteristic behaviors depending on the
next-nearest-neighbor interaction and the bond-alternation .
We discuss the lower excited states in comparison with the exact excitation
spectrums of an effective Hamiltonian. From the finite size effects,
characteristics of the lowest excited states are investigated. The
dispersionless mode of the lowest excitation appears in adequate sets of
and , indicating that the lowest excitation is localized
spatially and forms an isolated mode below the excitation continuum. We further
calculate the static structure factors. The largest intensity is located at
for small in fixed . With increasing , the
wavenumber of the largest intensity shifts towards , taking the
incommensurate value.Comment: to appear in Phys. Rev. B (2001
Relevance of Bcl-x expression in different types of endometrial tissues
<p>Abstract</p> <p>Objectives</p> <p>To explore the roles of Bcl-xl and Bcl-xs in the development and progression of endometrial carcinoma, and to analyze the correlation between Bcl-xl and Bcl-xs.</p> <p>Methods</p> <p>RT-PCR and Western-blot assay were applied to detect the expressions of Bcl-xl and Bcl-xs in endometrial tissues of various histomorphologic types.</p> <p>Results</p> <p>The Bcl-xl expression levels of simple and atypical hyperplasia endometrial tissues were not significantly different from that of normal endometrial tissue (both <it>P </it>> 0.05). On contrary, Bcl-xl expression in endometrial carcinoma tissue was significantly higher than the normal endometrial tissue (<it>P </it>= 0.00), which was correlated with the pathological grading of endometrial carcinoma (F = 5.33, <it>P </it>= 0.02). In addition, Bcl-xs mRNA level in simple hyperplasia endometrial tissue had no significant difference compared to that in normal endometrial tissue (<it>P </it>= 0.12), while the levels of atypical hyperplasia and endometrial carcinoma endometrial tissues were significantly different from the normal endometrial tissue (both <it>P </it>= 0.00). Furthermore, level of Bcl-xs mRNA was correlated with the clinical staging and lymph node metastasis of the endometrial carcinoma (<it>P </it>< 0.05). The expressions of Bcl-xl and Bcl-xs were negatively correlated with each other (<it>r </it>= -0.76).</p> <p>Conclusion</p> <p>The abnormal expressions of Bcl-xs and Bcl-xl were one of the molecular mechanisms for the pathogenesis of endometrial carcinoma, and altered ratio between these two might involve in the onset of endometrial carcinoma.</p
Magnetization Properties of Some Quantum Spin Ladders
The experimental realization of various spin ladder systems has prompted
their detailed theoretical investigations. Here we study the evolution of
ground state magnetization with an external magnetic field for two different
antiferromagnetic systems: a three-legged spin-1/2 ladder, and a two-legged
spin-1/2 ladder with an additional diagonal interaction. The finite system
density-matrix renormalization group method is employed for numerical studies
of the three-chain system, and an effective low-energy Hamiltonian is used in
the limit of strong interchain coupling to study the two- and three-chain
systems. The three-chain system has a magnetization plateau at one-third of the
saturation magnetization. The two-chain system has a plateau at zero
magnetization due to a gap above the singlet ground state. It also has a
plateau at half of the saturation magnetization for a certain range of values
of the couplings. We study the regions of transitions between plateaus
numerically and analytically, and find that they are described, at first order
in a strong-coupling expansion, by an XXZ spin-1/2 chain in a magnetic field;
the second order terms give corrections to the XXZ model. We also study
numerically some low-temperature properties of the three-chain system, such as
the magnetization, magnetic susceptibility and specific heat.Comment: Revtex, 26 pages including 17 epsf figures; a few minor changes; this
is the final published versio
Random Antiferromagnetic Spin-1/2 Chains with Competing Interactions
We study disordered antiferromagnetic spin-1/2 chains with nearest- and
further-neighbor interactions using the real-space renormalization-group
method. We find that the system supports two different phases, depending on the
ratio of the strength between nearest-neighbor and further-neighbor
interactions as well the bond randomness strength. For weak further neighbor
coupling the system is in the familiar random singlet phase, while stronger
further neighbor coupling drives the system to a large spin phase similar to
that found in the study of random antiferromagnetic-ferromagnetic spin chains.
The appearance of the large spin phase in the absence of ferromagnetic coupling
is due to the frustration introduced by further neighboring couplings, and is
unique to the disordered chains.Comment: 11 pages, 7 figure
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