4,984 research outputs found
Contextuality and Noncommutative Geometry in Quantum Mechanics
Observable properties of a classical physical system can be modelled deterministically as functions from the space of pure states to outcome values; dually, states can be modelled as functions from the algebra of observables to outcome values. The probabilistic predictions of quantum physics are contextual in that they preclude this classical assumption of reality: noncommuting observables, which are not assumed to be jointly measurable, cannot be consistently ascribed deterministic values even if one enriches the description of a quantum state. Here, we consider the geometrically dual objects of noncommutative operator algebras of observables as being generalisations of classical (deterministic) state spaces to the quantum setting and argue that these generalised state spaces represent the objects of study of noncommutative operator geometry. By adapting the spectral presheaf of Hamilton–Isham–Butterfield, a formulation of quantum state space that collates contextual data, we reconstruct tools of noncommutative geometry in an explicitly geometric fashion. In this way, we bridge the foundations of quantum mechanics with the foundations of noncommutative geometry à la Connes et al. To each unital C*- algebra A we associate a geometric object—a diagram of topological spaces collating quotient spaces of the noncommutative space underlying A —that performs the role of a generalised Gel'fand spectrum. We show how any functor F from compact Hausdorff spaces to a suitable target category C can be applied directly to these geometric objects to automatically yield an extension F~ acting on all unital C*-algebras. This procedure is used to give a novel formulation of the operator K0-functor via a finitary variant K~f of the extension K~ of the topological K-functor. We then delineate a C*-algebraic conjecture that the extension of the functor that assigns to a topological space its lattice of open sets assigns to a unital C*-algebra the Zariski topological lattice of its primitive ideal spectrum, i.e. its lattice of closed two-sided ideals. We prove the von Neumann algebraic analogue of this conjecture
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Oncogenic Gain of Function in Glioblastoma Is Linked to Mutant p53 Amyloid Oligomers.
Tumor-associated p53 mutations endow cells with malignant phenotypes, including chemoresistance. Amyloid-like oligomers of mutant p53 transform this tumor suppressor into an oncogene. However, the composition and distribution of mutant p53 oligomers are unknown and the mechanism involved in the conversion is sparse. Here, we report accumulation of a p53 mutant within amyloid-like p53 oligomers in glioblastoma-derived cells presenting a chemoresistant gain-of-function phenotype. Statistical analysis from fluorescence fluctuation spectroscopy, pressure-induced measurements, and thioflavin T kinetics demonstrates the distribution of oligomers larger than the active tetrameric form of p53 in the nuclei of living cells and the destabilization of native-drifted p53 species that become amyloid. Collectively, these results provide insights into the role of amyloid-like mutant p53 oligomers in the chemoresistance phenotype of malignant and invasive brain tumors and shed light on therapeutic options to avert cancer
Livre expressão do empregado nas redes sociais online frente ao poder patronal: uma análise da exposição crÃtica em face do empregador
Perante o cenário de diluição dos âmbitos público e privado, como também dos âmbitos laboral e extralaboral, frente aos avanços tecnológicos, surge o seguinte problema: de que forma o poder patronal poderá limitar a livre expressão do empregado nas redes sociais frente ao contrato de trabalho, primordialmente quando desta deriva uma crÃtica contra empregador? Para analisar o problema, parte-se de uma abordagem dedutiva para que o exposto possa ser aplicado concretamente, enquanto que o método de interpretação centra-se no sistemático-teleológico, porquanto considera-se o ordenamento jurÃdico como um conjunto de normas organizadas a satisfazer determinados fins. Como técnica de pesquisa, analisa-se o corpo doutrinário, bem como o arcabouço legislativo, primordialmente centrado na CLT, além dos preceitos constitucionais e da jurisprudência brasileira, por sua vez, centrada em análise de julgados do Tribunal Regional da 4ª Região, cujo corte temporal é de 01.06.2010 a 01.06.2019. Percebe-se que o empregado, ainda que se submeta a um contrato de trabalho, não perde a autonomia, nem os direitos fundamentais dos quais seja titular. Em sÃntese, os direitos fundamentais não são exercidos da mesma maneira, dentro e fora do ambiente de trabalho, sendo necessária, nas redes, maior cautela do empregado. Noutros termos, o empregado não perde o seu direito de crÃtica em face do empregador, observados os limites dos crimes contra a honra, em cujas hipóteses poderá haver dispensa por justa causa. Ainda assim, demostra-se a importância de manter-se o vÃnculo empregatÃcio por meio de canais de comunicação empregado-empregador, visando ao cultivo de um ambiente laboral saudável.Perante o cenário de diluição dos âmbitos público e privado, como também dos âmbitos laboral e extralaboral, frente aos avanços tecnológicos, surge o seguinte problema: de que forma o poder patronal poderá limitar a livre expressão do empregado nas redes sociais frente ao contrato de trabalho, primordialmente quando desta deriva uma crÃtica contra empregador? Para analisar o problema, parte-se de uma abordagem dedutiva para que o exposto possa ser aplicado concretamente, enquanto que o método de interpretação centra-se no sistemático-teleológico, porquanto considera-se o ordenamento jurÃdico como um conjunto de normas organizadas a satisfazer determinados fins. Como técnica de pesquisa, analisa-se o corpo doutrinário, bem como o arcabouço legislativo, primordialmente centrado na CLT, além dos preceitos constitucionais e da jurisprudência brasileira, por sua vez, centrada em análise de julgados do Tribunal Regional da 4ª Região, cujo corte temporal é de 01.06.2010 a 01.06.2019. Percebe-se que o empregado, ainda que se submeta a um contrato de trabalho, não perde a autonomia, nem os direitos fundamentais dos quais seja titular. Em sÃntese, os direitos fundamentais não são exercidos da mesma maneira, dentro e fora do ambiente de trabalho, sendo necessária, nas redes, maior cautela do empregado. Noutros termos, o empregado não perde o seu direito de crÃtica em face do empregador, observados os limites dos crimes contra a honra, em cujas hipóteses poderá haver dispensa por justa causa. Ainda assim, demostra-se a importância de manter-se o vÃnculo empregatÃcio por meio de canais de comunicação empregado-empregador, visando ao cultivo de um ambiente laboral saudável
Pentoxifylline, tocopherol, and sequestrectomy are effective for the management of advanced osteoradionecrosis of the jaws—a case series
Background:
The aim of the present study was to evaluate the efficacy of pentoxifylline and tocopherol for the management of osteoradionecrosis of the jaws. /
Methods:
Twenty-five patients diagnosed with osteoradionecrosis of the jaws treated with pentoxifylline 400 mg + tocopherol 400 mg three times daily (tid) were evaluated. Clinical records and image tests were reviewed. All patients were previously submitted to head and neck radiation therapy and presented with a clinical and radiographic diagnosis of osteoradionecrosis of the jaws. /
Results:
Following therapy with pentoxifylline and tocopherol, 76% (19/25) of the patients showed complete mucosal healing, in which 47.3% (9/19) did not undergo sequestrectomy. From this particular group, 77.7% (7/9) were in stage I and 33.3% (3/9) used the protocol for up to 3 months. Among those who underwent to sequestrectomy, complete mucosal healing was observed in 52.7% (10/19). Among these, 60% (6/10) were in stage I and 100% of the patients were using the protocol for more than 3 months. In all other patients, partial healing of the mucosa was observed since they presented advanced disease. These represented 24% of the sample (6/25), 66.6% (4/6) were in stage III, and 60% (4/6) used the protocol for over 6 months. /
Conclusion:
Pentoxifylline and tocopherol may provide effective management of osteoradionecrosis of the jaws, and the association with sequestrectomy may avoid major surgical procedures
Solving the Uncapacitated Single Allocation p-Hub Median Problem on GPU
A parallel genetic algorithm (GA) implemented on GPU clusters is proposed to
solve the Uncapacitated Single Allocation p-Hub Median problem. The GA uses
binary and integer encoding and genetic operators adapted to this problem. Our
GA is improved by generated initial solution with hubs located at middle nodes.
The obtained experimental results are compared with the best known solutions on
all benchmarks on instances up to 1000 nodes. Furthermore, we solve our own
randomly generated instances up to 6000 nodes. Our approach outperforms most
well-known heuristics in terms of solution quality and time execution and it
allows hitherto unsolved problems to be solved
Respiratory allergy to Blomia tropicalis: Immune response in four syngeneic mouse strains and assessment of a low allergen-dose, short-term experimental model
<p>Abstract</p> <p>Background</p> <p>The dust mite <it>Blomia tropicalis </it>is an important source of aeroallergens in tropical areas. Although a mouse model for <it>B. tropicalis </it>extract (<it>Bt</it>E)-induced asthma has been described, no study comparing different mouse strains in this asthma model has been reported. The relevance and reproducibility of experimental animal models of allergy depends on the genetic background of the animal, the molecular composition of the allergen and the experimental protocol.</p> <p>Objectives</p> <p>This work had two objectives. The first was to study the anti-<it>B. tropicalis </it>allergic responses in different mouse strains using a short-term model of respiratory allergy to <it>Bt</it>E. This study included the comparison of the allergic responses elicited by <it>Bt</it>E with those elicited by ovalbumin in mice of the strain that responded better to <it>Bt</it>E sensitization. The second objective was to investigate whether the best responder mouse strain could be used in an experimental model of allergy employing relatively low <it>Bt</it>E doses.</p> <p>Methods</p> <p>Groups of mice of four different syngeneic strains were sensitized subcutaneously with 100 μg of <it>Bt</it>E on days 0 and 7 and challenged four times intranasally, at days 8, 10, 12, and 14, with 10 μg of <it>Bt</it>E. A/J mice, that were the best responders to <it>Bt</it>E sensitization, were used to compare the <it>B. tropicalis</it>-specific asthma experimental model with the conventional experimental model of ovalbumin (OVA)-specific asthma. A/J mice were also sensitized with a lower dose of <it>Bt</it>E.</p> <p>Results</p> <p>Mice of all strains had lung inflammatory-cell infiltration and increased levels of anti-<it>Bt</it>E IgE antibodies, but these responses were significantly more intense in A/J mice than in CBA/J, BALB/c or C57BL/6J mice. Immunization of A/J mice with <it>Bt</it>E induced a more intense airway eosinophil influx, higher levels of total IgE, similar airway hyperreactivity to methacholine but less intense mucous production, and lower levels of specific IgE, IgG1 and IgG2 antibodies than sensitization with OVA. Finally, immunization with a relatively low <it>Bt</it>E dose (10 μg per subcutaneous injection per mouse) was able to sensitize A/J mice, which were the best responders to high-dose <it>Bt</it>E immunization, for the development of allergy-associated immune and lung inflammatory responses.</p> <p>Conclusions</p> <p>The described short-term model of <it>Bt</it>E-induced allergic lung disease is reproducible in different syngeneic mouse strains, and mice of the A/J strain was the most responsive to it. In addition, it was shown that OVA and <it>Bt</it>E induce quantitatively different immune responses in A/J mice and that the experimental model can be set up with low amounts of <it>Bt</it>E.</p
The effectiveness of public health interventions to reduce the health impact of climate change:a systematic review of systematic reviews
Climate change is likely to be one of the most important threats to public health in the coming years. Yet despite the large number of papers considering the health impact of climate change, few have considered what public health interventions may be of most value in reducing the disease burden. We aimed to evaluate the effectiveness of public health interventions to reduce the disease burden of high priority climate sensitive diseases
Monocytes regulate the mechanism of T-cell death by inducing Fas-mediated apoptosis during bacterial infection.
Monocytes and T-cells are critical to the host response to acute bacterial infection but monocytes are primarily viewed as amplifying the inflammatory signal. The mechanisms of cell death regulating T-cell numbers at sites of infection are incompletely characterized. T-cell death in cultures of peripheral blood mononuclear cells (PBMC) showed 'classic' features of apoptosis following exposure to pneumococci. Conversely, purified CD3(+) T-cells cultured with pneumococci demonstrated necrosis with membrane permeabilization. The death of purified CD3(+) T-cells was not inhibited by necrostatin, but required the bacterial toxin pneumolysin. Apoptosis of CD3(+) T-cells in PBMC cultures required 'classical' CD14(+) monocytes, which enhanced T-cell activation. CD3(+) T-cell death was enhanced in HIV-seropositive individuals. Monocyte-mediated CD3(+) T-cell apoptotic death was Fas-dependent both in vitro and in vivo. In the early stages of the T-cell dependent host response to pneumococci reduced Fas ligand mediated T-cell apoptosis was associated with decreased bacterial clearance in the lung and increased bacteremia. In summary monocytes converted pathogen-associated necrosis into Fas-dependent apoptosis and regulated levels of activated T-cells at sites of acute bacterial infection. These changes were associated with enhanced bacterial clearance in the lung and reduced levels of invasive pneumococcal disease
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