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Pneumoconiosis is characterized by chronic lung inflammation and fibrosis, and inflammation can promote pulmonary fibrosis, which in turn leads to pneumoconiosis. When a large shadow with a long diameter of not less than 2 cm and a short diameter of not less than 1 cm appears in the lung, it can be classified as stage â ¢ pneumoconiosis. This paper reports a case of stage â ¢ pneumoconiosis with a large shadow in the upper right lung accompanied by burr-like changes misdiagnosed as lung cancer by CT examination.When the large shadow lesions in patients with pneumoconiosis and lung cancer are difficult to distinguish on CT, an additional MRI examination, particularly T(2)W imaging sequence is useful sequence for identifying the two.
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Neoplasias Pulmonares , Pneumoconiose , Fibrose Pulmonar , Humanos , Pneumoconiose/diagnóstico , Pneumoconiose/patologia , Pulmão/patologia , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/patologia , Fibrose Pulmonar/patologia , Erros de DiagnósticoRESUMO
The miniaturization and integration of frequency-agile microwave circuits--relevant to electronically tunable filters, antennas, resonators and phase shifters--with microelectronics offers tantalizing device possibilities, yet requires thin films whose dielectric constant at gigahertz frequencies can be tuned by applying a quasi-static electric field. Appropriate systems such as BaxSr1-xTiO3 have a paraelectric-ferroelectric transition just below ambient temperature, providing high tunability. Unfortunately, such films suffer significant losses arising from defects. Recognizing that progress is stymied by dielectric loss, we start with a system with exceptionally low loss--Srn+1TinO3n+1 phases--in which (SrO)2 crystallographic shear planes provide an alternative to the formation of point defects for accommodating non-stoichiometry. Here we report the experimental realization of a highly tunable ground state arising from the emergence of a local ferroelectric instability in biaxially strained Srn+1TinO3n+1 phases with n ≥ 3 at frequencies up to 125 GHz. In contrast to traditional methods of modifying ferroelectrics-doping or strain-in this unique system an increase in the separation between the (SrO)2 planes, which can be achieved by changing n, bolsters the local ferroelectric instability. This new control parameter, n, can be exploited to achieve a figure of merit at room temperature that rivals all known tunable microwave dielectrics.
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In systems having an anisotropic electronic structure, such as the layered materials graphite, graphene, and cuprates, impulsive light excitation can coherently stimulate specific bosonic modes, with exotic consequences for the emergent electronic properties. Here we show that the population of E_{2g} phonons in the multiband superconductor MgB_{2} can be selectively enhanced by femtosecond laser pulses, leading to a transient control of the number of carriers in the σ-electronic subsystem. The nonequilibrium evolution of the material optical constants is followed in the spectral region sensitive to both the a- and c-axis plasma frequencies and modeled theoretically, revealing the details of the σ-π interband scattering mechanism in MgB_{2}.
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We report intense, narrow line-width, surface chemisorption-activated and reversible ultraviolet (UV) photoluminescence from radiative recombination of the two-dimensional electron gas (2DEG) with photoexcited holes at LaAlO3/SrTiO3. The switchable luminescence arises from an electron transfer-driven modification of the electronic structure via H-chemisorption onto the AlO2-terminated surface of LaAlO3, at least 2 nm away from the interface. The control of the onset of emission and its intensity are functionalities that go beyond the luminescence of compound semiconductor quantum wells. Connections between reversible chemisorption, fast electron transfer, and quantum-well luminescence suggest a new model for surface chemically reconfigurable solid-state UV optoelectronics and molecular sensing.
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Óxido de Alumínio/química , Técnicas Biossensoriais , Elétrons , Gases/química , Luminescência , Óxidos/química , Estrôncio/química , Propriedades de Superfície , Titânio/química , Raios UltravioletaRESUMO
Russian traditional fermented dairy foods have been consumed for thousands of years. However, little research has focused on exploiting lactic acid bacteria (LAB) resources and analyzing the LAB composition of Russian traditional fermented dairy foods. In the present study, we cultured LAB isolated from fermented mare and cow milks, sour cream, and cheese collected from Kalmykiya, Buryats, and Tuva regions of Russia. Seven lactobacillus species and the Bifidobacterium genus were quantified by quantitative PCR. The LAB counts in these samples ranged from 3.18 to 9.77 log cfu/mL (or per gram). In total, 599 LAB strains were obtained from these samples using de Man, Rogosa, and Sharpe agar and M17 agar. The identified LAB belonged to 7 genera and 30 species by 16S rRNA and murE gene sequencing and multiplex PCR assay. The predominant LAB isolates were Lactobacillus helveticus (176 strains) and Lactobacillus plantarum (63 strains), which represented 39.9% of all isolates. The quantitative PCR results revealed that counts of 7 lactobacilli species and Bifidobacterium spp. of 30 fermented cow milk samples ranged from 1.19±0.34 (Lactobacillus helveticus in Tuva) to 8.09±0.71 (Lactobacillus acidophilus in Kalmykiya) log cfu/mL of fermented cow milk (mean ± standard error). The numbers of Bifidobacterium spp., Lb. plantarum, Lb. helveticus, and Lb. acidophilus revealed no significant difference between the 3 regions; nevertheless, Lactobacillus paracasei, Lactobacillus fermentum, Lactobacillus sakei, and Lactobacillus delbrueckii ssp. bulgaricus exhibited different degrees of variation across 3 regions. The results demonstrate that traditional fermented dairy products from different regions of Russia have complex compositions of LAB species. The diversity of LAB might be related to the type of fermented dairy product, geographical origin, and manufacturing process.
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Proteínas de Bactérias/genética , Produtos Fermentados do Leite/microbiologia , DNA Bacteriano/genética , Microbiologia de Alimentos , Lactobacillaceae/genética , RNA Ribossômico 16S/genética , Lactobacillaceae/isolamento & purificação , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Multiplex , Filogenia , Recombinases Rec A/genética , Federação Russa , Análise de Sequência de DNARESUMO
Raman scattering measurements on multiferroic Pb(Fe(1/2)Nb(1/2))O3 over a wide temperature range from 10 to 500 K were performed. Very broad and overlapping peaks (first-order character) and a prominent high-frequency peak at approximately 1130 cm( - 1), which we assign as a two-phonon peak, were observed. These features showed remarkable changes in their Raman scattering intensity and spectral shape at the characteristic temperature T(*) â¼ 330 K, clearly showing a structural lattice change at around T(*). The temperature dependence of some stretching vibration modes of the BO(6) units revealed an anomalous frequency shift below T(N) approxiamtely 143 K. These anomalous deviations at T(N) of the phonon frequency are associated with the spin-phonon coupling mechanism. Complementary magnetic data confirmed a weak magnetic ordering at room temperature and interestingly showed an anomaly at about T(*). These results suggest an interplay between ferroelectric, structural and magnetic degrees of freedom in PFN, starting to be significant at around T(*).
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OBJECTIVE: To explore the therapeutic effects of quercetin on rats with encephalitis, especially on cell apoptosis, and the levels of HMGB-1 and TLR-4. MATERIALS AND METHODS: 32 healthy rats were equally assigned into ZC group (healthy group), NY group (encephalitis group), DJ group (60 ml quercetin group), and GJ group (240 ml quercetin group) followed by analysis of cell apoptosis, brain tissue water content, neurons, HMGB-1, TLR-4 and other inflammatory factors. RESULTS: The ZC group showed normal neuron volume and equitable staining; compared with ZC group, NY group showed neuron volume shrinkage and chromatin condensation; the neuron and color in DJ group were slightly better than NY group; the neuron volume in GJ group increased significantly and chromatin is distributed evenly. TLR-4, IL-4, IL-6, HMGB-1 in ZC and DJ group were significantly lower than those in NY group (p<0.05); IL-4, IL-6, HMGB-1 in GJ group significantly decreased compared with DJ group (p<0.05); MMP-9 enzyme activity in ZC and DJ group was significantly lower than NY group (p<0.05) with lower level in GJ group than DJ group (p<0.05). The water content was higher in brain tissue of NY group than ZC group (p<0.05) and lower in DJ group than NY group (p<0.05) with lower level in GJ group than DJ and NY group (all p<0.05). The hippocampal neurons and cortical neurons in ZC and DJ group were higher than those in NY group (p<0.05) and elevated in GJ group compared with DJ group and NY group (p<0.05). CONCLUSIONS: Quercetin is effective in treating encephalitis rats possibly through inhibition of neuronal cell apoptosis and level of HMGB-1 and TLR-4.
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Apoptose/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encefalite/tratamento farmacológico , Quercetina/farmacologia , Animais , Encéfalo/citologia , Encéfalo/fisiopatologia , Modelos Animais de Doenças , Encefalite/fisiopatologia , Feminino , Proteína HMGB1/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/patologia , Ratos , Receptor 4 Toll-Like/metabolismoRESUMO
We report pump-probe time resolved reflectivity experiments in a hybrid air-Ni metal-BaTiO(3)/SrTiO(3) oxide mirror phonon cavity. We demonstrate that the generated coherent acoustic phonon spectra of the impulsively excited metallic film can be inhibited or enhanced in the phonon cavity with respect to a Ni film directly grown on a SrTiO(3) substrate. The experiments are compared with simulations that highlight the role of the phonon density of states in the coherent acoustic emission, extending concepts at the base of the optical Purcell effect to the field of phononics.
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We demonstrate the dramatic effect of film thickness on the ferroelectric phase transition temperature Tc in strained BaTiO3 films grown on SrTiO3 substrates. Using variable-temperature ultraviolet Raman spectroscopy enables measuring Tc in films as thin as 1.6 nm, and a film thickness variation from 1.6 to 10 nm leads to Tc tuning from 70 to about 925 K. Raman data are consistent with synchrotron x-ray scattering results, which indicate the presence of 180 degrees domains below Tc, and thermodynamic phase-field model calculations of Tc as a function of thickness.
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OBJECTIVE: To investigate the prevalence and vertical transmission rate of Toxoplasma gondii infections among in parturient women in Wuhu City, so as to provide reference for the prevention and control of toxoplasmosis among pregnant women in the city. METHODS: Parturient women's venous blood samples and neonatal heel blood samples were collected in Wuhu City and prepared into filter-paper blood samples. The prevalence and vertical transmission rate of T. gondii infections were detected using the loop -mediated isothermal amplification (LAMP) assay among the parturient women. RESULTS: There were three positive samples detected in the 475 filter-paper blood samples from the parturient women, with a mean positive rate of 0.63%. The prevalence of T. gondii infection was 0 in pregnant women at ages of < 20 years (0/5) and at an advanced maternal age (0/24), while the prevalence was 0.67% (3/446) in pregnant women at an appropriate maternal age. T. gondii infection was detected in 2 filter-paper blood samples from newborns, with a vertical transmission rate of 66.67%. CONCLUSIONS: There is T. gondii infection in the parturient women and a high vertical transmission rate of T. gondii infection is detected in Wuhu City. The awareness of the potential risk factors of toxoplasmosis should be improved among pregnant women to prevent the damages of toxoplasmosis to humans.
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Complicações Parasitárias na Gravidez , Toxoplasma , Toxoplasmose , Adulto , Anticorpos Antiprotozoários/sangue , Cidades , Feminino , Humanos , Recém-Nascido , Gravidez , Complicações Parasitárias na Gravidez/epidemiologia , Complicações Parasitárias na Gravidez/mortalidade , Prevalência , Estudos Soroepidemiológicos , Toxoplasmose/epidemiologia , Toxoplasmose/mortalidade , Toxoplasmose/transmissão , Adulto JovemRESUMO
We report on structural and electronic properties of defects in chemical vapor-deposited monolayer and few-layer MoS2 films. Scanning tunneling microscopy, Kelvin probe force microscopy, and transmission electron microscopy were used to obtain high resolution images and quantitative measurements of the local density of states, work function and nature of defects in MoS2 films. We track the evolution of defects that are formed under heating and electron beam irradiation. We observe formation of metastable domains with different work function values after annealing the material in ultra-high vacuum to moderate temperatures. We attribute these metastable values of the work function to evolution of crystal defects forming during the annealing. The experiments show that sulfur vacancies formed after exposure to elevated temperatures diffuse, coalesce, and migrate bringing the system from a metastable to equilibrium ground state. The process could be thermally or e-beam activated with estimated energy barrier for sulfur vacancy migration of 0.6 eV in single unit cell MoS2. Even at equilibrium conditions, the work function and local density of states values are strongly affected near grain boundaries and edges. The results provide initial estimates of the thermal budgets available for reliable fabrication of MoS2-based integrated electronics and indicate the importance of defect control and layer passivation.
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The nature of the metal-insulator transition in thin films and superlattices of LaNiO3 only a few unit cells in thickness remains elusive despite tremendous effort. Quantum confinement and epitaxial strain have been evoked as the mechanisms, although other factors such as growth-induced disorder, cation non-stoichiometry, oxygen vacancies, and substrate-film interface quality may also affect the observable properties of ultrathin films. Here we report results obtained for near-ideal LaNiO3 films with different thicknesses and terminations grown by atomic layer-by-layer laser molecular beam epitaxy on LaAlO3 substrates. We find that the room-temperature metallic behavior persists until the film thickness is reduced to an unprecedentedly small 1.5 unit cells (NiO2 termination). Electronic structure measurements using X-ray absorption spectroscopy and first-principles calculation suggest that oxygen vacancies existing in the films also contribute to the metal-insulator transition.
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Bulk niobium Superconducting Radio-Frequency cavities are a leading accelerator technology. Their performance is limited by the cavity loss and maximum acceleration gradient, which are negatively affected by vortex penetration into the superconductor when the peak magnetic field at the cavity wall surface exceeds the vortex penetration field (Hvp). It has been proposed that coating the inner wall of an SRF cavity with superconducting thin films increases Hvp. In this work, we utilized Nb ellipsoid to simulate an inverse SRF cavity and investigate the effect of coating it with magnesium diboride layer on the vortex penetration field. A significant enhancement of Hvp was observed. At 2.8 K, Hvp increased from 2100 Oe for an uncoated Nb ellipsoid to 2700 Oe for a Nb ellipsoid coated with ~200 nm thick MgB2 thin film. This finding creates a new route towards achieving higher acceleration gradient in SRF cavity accelerator beyond the theoretical limit of bulk Nb.
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Complex oxide heterostructures display some of the most chemically abrupt, atomically precise interfaces, which is advantageous when constructing new interface phases with emergent properties by juxtaposing incompatible ground states. One might assume that atomically precise interfaces result from stoichiometric growth. Here we show that the most precise control is, however, obtained by using deliberate and specific non-stoichiometric growth conditions. For the precise growth of Sr(n+1)Ti(n)O(n+1) Ruddlesden-Popper (RP) phases, stoichiometric deposition leads to the loss of the first RP rock-salt double layer, but growing with a strontium-rich surface layer restores the bulk stoichiometry and ordering of the subsurface RP structure. Our results dramatically expand the materials that can be prepared in epitaxial heterostructures with precise interface control--from just the n = ∞ end members (perovskites) to the entire RP homologous series--enabling the exploration of novel quantum phenomena at a richer variety of oxide interfaces.
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The energy gap is the most fundamental property of a superconductor. MgB(2), a superconductor discovered in 2001, exhibits two different superconducting gaps caused by the different electron-phonon interactions in two weakly interacting bands. Theoretical calculations predict that the gap values should also vary across the Fermi surface sheets of MgB(2). However, until now, no such variation has been observed. It has been suggested that two gap values were sufficient to describe real MgB(2) samples. Here we present an electron tunnelling spectroscopy study on MgB(2)/native oxide/Pb tunnel junctions that clearly shows a distribution of gap values, confirming the importance of the anisotropic electron-phonon interaction. The gap values, and their spreads found from the tunnel junction measurements, provide valuable experimental tests for various theoretical approaches to the multi-band superconductivity in MgB(2).
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Compostos de Boro/química , Compostos de Magnésio/química , Espectroscopia Fotoeletrônica/métodos , Física/métodos , Condutividade Elétrica , Eletrodos , Elétrons , Chumbo , Modelos Estatísticos , Movimento (Física) , Fônons , Espalhamento de Radiação , Propriedades de Superfície , TemperaturaRESUMO
We report a UV-Raman study of folded acoustic vibrations in epitaxial ferroelectric BaTiO3/SrTiO3 superlattices. The folded acoustic doublets show an anomalous temperature dependence disappearing above the ferroelectric transition, which is tuned by varying the thickness of the BaTiO3 and SrTiO3 layers. A mechanism involving the acoustic phonon modulation of the spatially periodic ferroelectric polarization explains the observed temperature dependence. These results demonstrate the strong coupling between sound, charge, and light in these multifunctional nanoscale ferroelectrics.
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We report a large normal-state magnetoresistance with temperature-dependent anisotropy in very clean epitaxial MgB2 thin films (residual resistivity much smaller than 1 microOmega cm) grown by hybrid physical-chemical vapor deposition. The magnetoresistance shows a complex dependence on the orientation of the applied magnetic field, with a large magnetoresistance (Delta(rho)/(rho)0=136%) observed for the field H perpendicular ab plane. The angular dependence changes dramatically as the temperature is increased, and at high temperatures the magnetoresistance maximum changes to H||ab. We attribute the large magnetoresistance and the evolution of its angular dependence with temperature to the multiple bands with different Fermi surface topology in MgB2 and the relative scattering rates of the sigma and pi bands, which vary with temperature due to stronger electron-phonon coupling for the sigma bands.
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We demonstrated that ultraviolet Raman spectroscopy is an effective technique to measure the transition temperature (Tc) in ferroelectric ultrathin films and superlattices. We showed that one-unit-cell-thick BaTiO3 layers in BaTiO3/SrTiO3 superlattices are not only ferroelectric (with Tc as high as 250 kelvin) but also polarize the quantum paraelectric SrTiO3 layers adjacent to them. Tc was tuned by approximately 500 kelvin by varying the thicknesses of the BaTiO3 and SrTiO3 layers, revealing the essential roles of electrical and mechanical boundary conditions for nanoscale ferroelectricity.
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Angle-resolved photoemission spectroscopy reveals very surprising strain-induced effects on the electronic band dispersion of epitaxial La(2-x)Sr(x)CuO(4-delta) thin films. In strained films we measure a band that crosses the Fermi level (E(F)) well before the Brillouin zone boundary. This is in contrast to the flat band reported in unstrained single crystals and in our unstrained films, as well as in contrast to the band flattening predicted by band structure calculations for in-plane compressive strain. In spite of the density of states reduction near E(F), the critical temperature increases in strained films with respect to unstrained samples. These results require a radical departure from commonly accepted notions about strain effects on high temperature superconductors, with possible general repercussions on superconductivity theory.
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The newly discovered 39-K superconductor MgB2 holds great promise for superconducting electronics. Like the conventional superconductor Nb, MgB2 is a phonon-mediated superconductor, with a relatively long coherence length. These properties make the prospect of fabricating reproducible uniform Josephson junctions, the fundamental element of superconducting circuits, much more favourable for MgB2 than for high-temperature superconductors. The higher transition temperature and larger energy gap of MgB2 promise higher operating temperatures and potentially higher speeds than Nb-based integrated circuits. However, success in MgB2 Josephson junctions has been limited because of the lack of an adequate thin-film technology. Because a superconducting integrated circuit uses a multilayer of superconducting, insulating and resistive films, an in situ process in which MgB2 is formed directly on the substrate is desirable. Here we show that this can be achieved by hybrid physical-chemical vapour deposition. The epitaxially grown MgB2 films show a high transition temperature and low resistivity, comparable to the best bulk samples, and their surfaces are smooth. This advance removes a major barrier for superconducting electronics using MgB2.