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1.
Nat Commun ; 15(1): 1634, 2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38395918

RESUMO

Lithium- and manganese-rich layered oxide cathode materials have attracted extensive interest because of their high energy density. However, the rapid capacity fading and serve voltage decay over cycling make the waste management and recycling of key components indispensable. Herein, we report a facile concentrated solar radiation strategy for the direct recycling of Lithium- and manganese-rich cathodes, which enables the recovery of capacity and effectively improves its electrochemical stability. The phase change from layered to spinel on the particle surface and metastable state structure of cycled material provides the precondition for photocatalytic reaction and thermal reconstruction during concentrated solar radiation processing. The inducement of partial inverse spinel phase is identified after concentrated solar radiation treatment, which strongly enhances the redox activity of transition metal cations and oxygen anion, and reversibility of lattice structure. This study sheds new light on the reparation of spent cathode materials and designing high-performance compositions to mitigate structural degradation.

2.
Avian Pathol ; 53(3): 155-163, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38206316

RESUMO

RESEARCH HIGHLIGHTS: Samples of suspected FAdV-infected waterfowl from farms in Shandong Province were collected from 2019 to 2022.Single infections with FAdV were less frequent than mixed infections.477 out of 792 samples (60.23%) tested positive for FAdV nucleic acids.Detection rate of FAdV was 65.47% in fattening duck farms, 55.73% in breeder duck farms and 54.55% in fattening geese farms.


Assuntos
Infecções por Adenoviridae , Aviadenovirus , Doenças das Aves Domésticas , Animais , Patos , Gansos , Galinhas , Infecções por Adenoviridae/epidemiologia , Infecções por Adenoviridae/veterinária , Filogenia , Doenças das Aves Domésticas/epidemiologia , Aviadenovirus/genética , China/epidemiologia
3.
Poult Sci ; 103(2): 103301, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38113704

RESUMO

Ducks infected with duck circovirus (DuCV) show symptoms such as feather loss, growth retardation and low body weight in the flock. The virus induces immunosuppression and increases the prevalence of infection with other pathogens. However, most studies on duck circovirus were focused on coinfection, and fewer studies had been conducted on the pathogenicity of duck circovirus alone. The aim of the present study was to investigate the pathogenesis of DuCV-1 in experimentally infected specific pathogen-free ducks. In this study, we sequenced the whole genome of a strain of duck circovirus and identified the virus genotype as DuCV-1b. This strain of duck circovirus was named SDLH(OR567883). Animal pathogenicity experiments were then conducted, wherein specific pathogen-free ducks were infected by mucosal injection and abdominal injection. Infected ducks were sampled for 4 consecutive weeks after infection and showed symptoms of dwarfism. We further examined the replication of DuCV-1 in the ducks. The highest virus titers in the 2 infection groups were found in the liver and spleen, with different results for the different routes of infection. Pathological sections of duck organs were made and it was found that organs such as the liver and spleen were damaged by DuCV-1. In conclusion, our experimental results indicate that DuCV-1 can infect ducks individually and cause widespread organ damage in infected ducks.


Assuntos
Infecções por Circoviridae , Circovirus , Doenças das Aves Domésticas , Animais , Virulência , Galinhas/genética , Sequência de Bases , Circovirus/genética , Infecções por Circoviridae/veterinária
4.
Nat Commun ; 14(1): 4611, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37528109

RESUMO

Metal halide perovskites have shown great promise as a potential candidate for next-generation solid state lighting and display technologies. However, a generic organic ligand-free and antisolvent-free solution method to fabricate highly efficient full-color perovskite light-emitting diodes has not been realized. Herein, by utilizing porous alumina membranes with ultra-small pore size as templates, we have successfully fabricated crystalline all-inorganic perovskite quantum wire arrays with ultrahigh density and excellent uniformity, using a generic organic ligand-free and anti-solvent-free solution method. The quantum confinement effect, in conjunction with the high light out-coupling efficiency, results in high photoluminescence quantum yield for blue, sky-blue, green and pure-red perovskite quantum wires arrays. Consequently, blue, sky-blue, green and pure-red LED devices with spectrally stable electroluminescence have been successfully fabricated, demonstrating external quantum efficiencies of 12.41%, 16.49%, 26.09% and 9.97%, respectively, after introducing a dual-functional small molecule, which serves as surface passivation and hole transporting layer, and a halide vacancy healing agent.

5.
Ecol Evol ; 13(2): e9829, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36844675

RESUMO

Numerous gut microbial studies have focused on bacteria. However, archaea, viruses, fungi, protists, and nematodes are also regular residents of the gut ecosystem. Little is known about the composition and potential interactions among these six kingdoms in the same samples. Here, we unraveled the complex connection among them using approximately 123 gut metagenomes from 42 mammalian species (including carnivores, omnivores, and herbivores). We observed high variation in bacterial and fungal families and relatively low variation in archaea, viruses, protists, and nematodes. We found that some fungi in the mammalian intestine might come from environmental sources (e.g., soil and dietary plants), and some might be native to the intestine (e.g., the occurrence of Neocallimastigomycetes). The Methanobacteriaceae and Plasmodiidae families (archaea and protozoa, respectively) were predominant in these metagenomes, whereas Onchocercidae and Trichuridae were the two most common nematodes, and Siphoviridae and Myoviridae the two most common virus families in these mammalian gut metagenomes. Interestingly, most of the pairwise co-occurrence patterns were significantly positive among these six kingdoms, and significantly negative networks mainly occurred between fungi and prokaryotes (both bacteria and archaea). Our study revealed some inconvenient characteristics in the mammalian gut microorganism ecosystem: (1) the community formed by members of the analyzed kingdoms reflects the life history of the host and the potential threat posed by pathogenic protists and nematodes in mammals; and (2) the networks suggest the existence of predicted mutualism among members of these six kingdoms and of the predicted competition, mainly among fungi and other kingdoms.

6.
Nano Lett ; 22(7): 3062-3070, 2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35312323

RESUMO

Charge collection narrowing (CCN) has been reported to be an efficient strategy to achieve optical filter-free narrowband photodetection (NPD) with metal halide perovskite (MHP) single crystals. However, the necessity of utilizing thick crystals in CCN limits their applications in large scale, flexible, self-driven, and high-performance optoelectronics. Here, for the first time, we fabricate vertically integrated MHP quantum wire/nanowire (QW/NW) array based photodetectors in nanoengineered porous alumina membranes (PAMs) showing self-driven broadband photodetection (BPD) and NPD capability simultaneously. Two cutoff detection edges of the NPDs are located at around 770 and 730 nm, with a full-width at half-maxima (fwhm) of around 40 nm. The optical bandgap difference between the NWs and the QWs, in conjunction with the high carrier recombination rate in QWs, contributes to the intriguing NPD performance. Thanks to the excellent mechanical flexibility of the PAMs, a flexible NPD is demonstrated with respectable performance. Our work here opens a new pathway to design and engineer a nanostructured MHP for novel color selective and full color sensing devices.

7.
Comput Struct Biotechnol J ; 19: 4676-4683, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34504662

RESUMO

Many studies highlight that host phylogeny and diet are the two main factors influencing the animal gut microbiota. However, the internal mechanisms driving the evolution of animal gut microbiota may be more complex and complicated than we previously realized. Here, based on a large-scale meta-analysis of animal gut microbiota (16 s RNA gene data from approximately 1,800 samples; 108 metagenomes) across a wide taxonomic range of hosts, from invertebrate to vertebrate, we found high similarity in the gut microbial community (high proportion of Gammaproteobacteria (Pseudomonas)) of invertebrate insects and vertebrate bamboo-eating pandas (giant panda and red panda), which might be associated their plant-eating behavior and the presence of oxygen in the intestinal tract. A Pseudomonas strain-level analysis using 108 metagenomes further revealed that the response to either host niches or selection by the host might further lead to host-specific strains (or sub-strains) among the different hosts congruent with their evolutionary history. In this study, we uncovered new insights into the current understanding of the evolution of animals and their gut microbiota.

8.
Microbiol Spectr ; 9(1): e0075621, 2021 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-34406815

RESUMO

It is commonly understood that dietary nutrition will influence the composition and function of the animal gut microbiome. However, the transmission of organisms from the diet-source microbiome to the animal gut microbiome in the natural environment remains poorly understood, and elucidating this process may help in understanding the evolution of herbivores and plant defenses. Here, we investigated diet-source microbiome transmission across a range of herbivores (insects and mammals) living in both captive and wild environments. We discovered a host bias among cohabitating herbivores (leaf-eating insects and deer), where a significant portion of the herbivorous insect gut microbiome may originate from the diet, while in deer, only a tiny fraction of the gut microbiome is of dietary origin. We speculated that the putative difference in the oxygenation level in the host digestion systems would lead to these host biases in plant-source (diet) microbiome transmission due to the oxygenation living condition of the dietary plant's symbiotic microbiome. IMPORTANCE We discovered a host bias among cohabitating herbivores (leaf-eating insects and deer), where a significant portion of the herbivorous insect gut microbiome may originate from the diet, while in deer, only a tiny fraction of the gut microbiome is of dietary origin. We speculated that the putative difference in the oxygenation level in the host digestion systems would lead to these host biases in plant-source (diet) microbiome transmission due to the oxygenation living condition of the dietary plant's symbiotic microbiome. This study shed new light on the coevolution of herbivory and plant defense.


Assuntos
Cervos/microbiologia , Insetos/microbiologia , Microbiota , Plantas/microbiologia , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Cervos/fisiologia , Dieta/veterinária , Comportamento Alimentar , Herbivoria/fisiologia , Insetos/fisiologia , Simbiose
9.
Adv Mater ; 33(36): e2102055, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34296476

RESUMO

As the most promising lead-free one, tin-halides based perovskite solar cells still suffer from the severe bulk-defect due to the easy oxidation of tin from divalent to tetravalent. Here, a general and effective strategy is delivered to modulate the microstructure of 2D/3D heterogeneous tin-perovskite absorber films by substituting FAI with FPEABr in FASnI3 . The introduction of 2D phase can induce highly oriented growth of 3D FASnI3 and it is revealed in the optimal 2D/3D film that 2D phase embraces 3D grains and locates at the surfaces and grain boundaries. The FPEA+ based 2D tin-perovskite capping layer can offer a reducing atmosphere for vulnerable 3D FASnI3 grains. The unique microstructure effectively suppresses the well-known oxidation from Sn2+ to Sn4+ , as well as decreasing defect density, which leads to a remarkable enhanced device performance from 9.38% to 14.81% in conversion efficiency. The certified conversion efficiency of 14.03% announces a new record and moves a remarkable step from the last one (12.4%). Besides of this breakthrough, this work definitely paves a new way to fabricate high-quality tin-perovskite absorber film by constructing effective 2D/3D microstructures.

10.
J Phys Chem Lett ; 12(19): 4735-4741, 2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-33983026

RESUMO

Because of the toxicity of water-soluble lead, the recycling of organic-inorganic lead-halides perovskite solar cells (PSCs) has attracted increasing attention. Here, we report a highly reliable two-step process to recycle cost-dominated indium-tin-oxide (ITO) substrates coated with NiOx and regenerate their based PSCs by function of dialkylamines. The champion recycled PSC can achieve 20% in conversion-efficiency, higher than 17.92% of the fresh one. Strikingly, the regenerated devices can remain superior to the fresh ones in the first 7 of 10 recycles. The comprehensive X-ray photoelectronic spectroscopy analysis reveals that dipropylamine has a suitable interaction with NiOx surfaces by Ni-N coordination, enabling its effective interfacial passivation and template effect of high-quality growth of perovskites. That leads to the suppressed nonradiative recombination of both interfacial and bulk, and finally improves the device performances. The dialkylamines driven two-step recycling process offers a promising and highly reproducible strategy to recycle PSCs, especially the cost-dominated NiOx/ITO substrates.

11.
ACS Appl Mater Interfaces ; 13(22): 26180-26186, 2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34036789

RESUMO

When scaling the lateral size of a ferroelectric random access memory (FeRAM) device down to the nanometer range, the polarization switching-induced displacement current becomes small and challenging to detect, which greatly limits the storage density of FeRAM. Here, we report the observation of significantly enhanced injection currents, much larger than typical switching currents, induced by polarization switching in BiFeO3 thin films via conductive atomic force microscopy. Interestingly, this injected current can be effectively modulated by applying mechanical force. As the loading force increases from ∼50 to ∼750 nN, the magnitude of the injected current increases and the critical voltage to trigger the current injection decreases. Notably, changing the loading force by an order of magnitude increases the peak current by 2-3 orders of magnitude. The mechanically boosted injected current could be useful for the development of high-density FeRAM devices. The mechanical modulation of the injected current may be attributed to the mechanical force-induced changes in the barrier height and interfacial layer width.

12.
PeerJ ; 9: e10860, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33604195

RESUMO

An increasing body of research has revealed that social behavior shapes the animal gut microbiome community and leads to the similarity among the same social group. However, some additional factors (e.g., diet and habitat within each social group) may also contribute to this similarity within the social group and dissimilarity between social groups. Here, we investigated the potential correlation between social behavior and the gut microbiome community in 179 musk deer from four breeding regions in the Maerkang Captive Center, Sichuan. The dominant gut microbiome phyla in the musk deer in this study were Firmicutes, Bacteroidetes, and Proteobacteria. We found significant effects on the alpha and beta diversity of the gut microbiome due to the breeding regions. The similarity within breeding regions was higher than that between the breeding regions. Due to their solitary lifestyle, captive musk deer are raised in single cages with no direct social contact most of the time. Deer in all of the breeding regions have the same diet and similar living conditions. However, during each mating season from November to January, in each region, one adult male and about six adult females will be put together into a large cage. Social behavior happens during cohabitation, including mating behavior, grooming within the same sex or between different sexes, and other social contact. Therefore, we speculated that high similarity within the breeding region might be associated with the social behavior during the mating season. This was a simple and straightforward example of the relationship between animal social behavior and the gut microbiome.

13.
Sci Bull (Beijing) ; 66(10): 991-1002, 2021 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-36654256

RESUMO

Perovskite solar cells (PSCs) commonly exhibit significant performance degradation due to ion migration through the top charge transport layer and ultimately metal electrode corrosion. Here, we demonstrate an interfacial management strategy using a boron chloride subphthalocyanine (Cl6SubPc)/fullerene electron-transport layer, which not only passivates the interfacial defects in the perovskite, but also suppresses halide diffusion as evidenced by multiple techniques, including visual element mapping by electron energy loss spectroscopy. As a result, we obtain inverted PSCs with an efficiency of 22.0% (21.3% certified), shelf life of 7000 h, T80 of 816 h under damp heat stress (compared to less than 20 h without Cl6SubPc), and initial performance retention of 98% after 2000 h at 80 °C in inert environment, 90% after 2034 h of illumination and maximum power point tracking in ambient for encapsulated devices and 95% after 1272 h outdoor testing ISOS-O-1. Our strategy and results pave a new way to move PSCs forward to their potential commercialization solidly.

14.
J Sci Food Agric ; 100(5): 2074-2081, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31875960

RESUMO

BACKGROUND: A mouse model in which diabetes mellitus was induced by low-dose streptozotocin (STZ) injection combined with a high-fat diet was used to study the effect of two water cress (Lepidium savitum) preparations. Diabetic mice were treated with dried cress powder or with water-soluble extracts (tested at two doses), together with proper control groups. The mice were evaluated after 4 weeks of continuous intervention for type 2 diabetic and associated markers. We determined blood glucose, body weight, total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), serum insulin levels, and DNA integrity of hepatic cells. The concentrations of malondialdehyde (MDA) and lipid peroxide (LPO) and the activities of four enzymes that are part of the antioxidant defense system were determined in liver samples, as well as gene expression (by semi-quantitative reverse transcription polymerase chain reaction) and enzyme activity of IRS-1, IRS-2, PI3K, AKT-2, and GLUT4. RESULTS: After 4 weeks of intervention, the levels of TC, TG, and LDL cholesterol were significantly (P < 0.5) decreased and HDL cholesterol was significantly increased. Enzyme activities of liver superoxide dismutase, glutathione, glutathione peroxidase, and catalase were significantly increased, whereas MDA and LPO concentrations were significantly reduced. The transcription level of the five genes assessed was increased, with corresponding increases in protein expression. CONCLUSION: Oral uptake of garden cress can significantly reduce the blood glucose and improve the blood lipid metabolism of diabetic mice. Considerable improvements in the activity of antioxidant defense enzymes were observed in type 2 diabetic mice that improved the body's antioxidant emergency response. © 2019 Society of Chemical Industry.


Assuntos
Glicemia/metabolismo , Dieta Hiperlipídica , Lepidium sativum/química , Lipídeos/sangue , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Fragmentação do DNA , Diabetes Mellitus Experimental/prevenção & controle , Regulação da Expressão Gênica , Transportador de Glucose Tipo 4/genética , Transportador de Glucose Tipo 4/metabolismo , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Hemoglobinas Glicadas/metabolismo , Hipoglicemiantes/farmacologia , Insulina/sangue , Proteínas Substratos do Receptor de Insulina/genética , Proteínas Substratos do Receptor de Insulina/metabolismo , Peróxidos Lipídicos/metabolismo , Masculino , Malondialdeído/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Estresse Oxidativo/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Extratos Vegetais/farmacologia , Superóxido Dismutase/metabolismo , Triglicerídeos/sangue
15.
ACS Appl Mater Interfaces ; 11(51): 48556-48563, 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31786921

RESUMO

Simultaneously improving efficiency and stability, which are particularly crucial factors for the commercialization of perovskite solar cells (PSCs), remains a major challenge. For high-efficiency normal PSCs, the development of stable dopant-free hole-transport materials (HTMs) seems imperative. Here, we developed potential donor-acceptor small molecules (BTTI) as HTMs for normal planar PSCs. Through tailoring its alkyl side-chain length as BTTI-C6, BTTI-C8, and BTTI-C12, our results show that upon shortening the side chain of BTTI, the hole mobility, film-forming capability, and resultant device performance were remarkably improved, with the device conversion efficiencies of 19.69% for BTTI-C6, 18.89% for BTTI-C8, and 17.49% for BTTI-C12. Meanwhile, compared to those made with the routine doped Spiro-OMeTAD, devices based on our dopant-free HTMs exhibited significantly improved stability. This work paves the way to the development of effective dopant-free HTMs for high-performance PSCs.

16.
ChemSusChem ; 12(22): 5007-5014, 2019 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-31468722

RESUMO

The promising tin perovskite solar cells (PSCs) suffer from the oxidation of Sn2+ to Sn4+ , leading to a disappointing conversion efficiency along with poor stability. In this work, phenylethylammonium bromide (PEABr) was employed to form an ultrathin, low-dimensional perovskite layer on the surface of the FASnI3 (FA=formamidinium) absorber film to improve the interface of perovskite/PCBM ([6,6]-phenyl-C61 -butyricacid methyl) in the inverted planar device structure of the ITO (indium-doped tin oxide)/PEDOT:PSS [poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate]/perovskite/[6,6]-phenyl-C61 -butyricacid methyl (PCBM)/BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) electrode. The device efficiency was enhanced from 4.77 to 7.86 % by this PEABr treatment. A series of characterizations proved that this modification could improve the crystallinity of the FASnI3 perovskite by incorporating Br and forming an ultrathin, low-dimensional perovskite layer at the interface, which led to the effective suppression of Sn2+ oxidation, improved band level alignment, and decreased defect density. These effects contributed to the clear enhancement of conversion efficiency. Moreover, this treatment also led to remarkably enhanced device stability, with approximately 80 % of the initial efficiency retained after 350 h light soaking, whereas the control device failed within 140 h. This work deepens our understanding of the suppression effect of PEABr on the oxidation of Sn2+ and paves a new way to fabricate promising tin halide PSCs by facile interface engineering.

17.
Adv Mater ; 31(5): e1804285, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30520163

RESUMO

Wearable and portable devices with desirable flexibility, operational safety, and long cruising time, are in urgent demand for applications in wireless communications, multifunctional entertainments, personal healthcare monitoring, etc. Herein, a monolithically integrated self-powered smart sensor system with printed interconnects, printed gas sensor for ethanol and acetone detection, and printable supercapacitors and embedded solar cells as energy sources, is successfully demonstrated in a wearable wristband fashion by utilizing inkjet printing as a proof-of-concept. In such a "wearable wristband", the harvested solar energy can either directly drive the sensor and power up a light-emitting diode as a warning signal, or can be stored in the supercapacitors in a standby mode, and the energy released from supercapacitors can compensate the intermittency of light illumination. To the best of our knowledge, the demonstration of such a self-powered sensor system integrated onto a single piece of flexible substrate in a printable and additive manner has not previously been reported. Particularly, the printable supercapacitors deliver an areal capacitance of 12.9 mF cm-2 and the printed SnO2 gas sensor shows remarkable detection sensitivity under room temperature. The printable strategies for device fabrication and system integration developed here show great potency for scalable and facile fabrication of a variety of wearable devices.

18.
Magn Reson Med ; 76(1): 20-31, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26198052

RESUMO

PURPOSE: Develop a practical comprehensive package for proactive management of parallel radiofrequency (RF) transmission. METHODS: With a constrained optimization framework and predictive models from a prescan based multichannel calibration, we presented a method supporting design and optimization of parallel RF excitation pulses that accurately obey the forward/reflected peak and average power limits of the RF power amplifiers in parallel transmit imaging experiments and Bloch simulations. Moreover, local SAR limits were incorporated into the parallel RF excitation pulses using electromagnetic field simulations. Virtual transmit coils concept for minimization of reflected power (effecting subject-specific matching) was additionally demonstrated by leveraging experimentally calibrated power models. RESULTS: Incorporation of experimentally calibrated power prediction models resulted in accurate compliance with prescribed hardware and global specific absorption rate (SAR) limits. Incorporation of spatial average 10 g SAR models, facilitated by simplifying numerical approximations, provided assurance of patient safety. RF pulses designed with various constraints demonstrated excellent excitation fidelity-the normalized root-mean-square error of the simulated excitation profiles was 2.6% for the fully constrained pulses, comparable to that of the unconstrained pulses. An RF shimming example showed a reduction of the reflected-to-forward power ratio to 1.7% from a conventional approach's 8.1%. CONCLUSION: Using the presented RF pulse design method, effective proactive management of the multifaceted power and SAR limits was demonstrated in experimental and simulation studies. Magn Reson Med 76:20-31, 2016. © 2015 Wiley Periodicals, Inc.


Assuntos
Desenho Assistido por Computador , Imageamento por Ressonância Magnética/métodos , Modelos Teóricos , Exposição à Radiação/análise , Monitoramento de Radiação/métodos , Proteção Radiológica/métodos , Simulação por Computador , Campos Eletromagnéticos , Humanos , Imageamento por Ressonância Magnética/instrumentação , Imagens de Fantasmas , Exposição à Radiação/prevenção & controle , Monitoramento de Radiação/instrumentação , Ondas de Rádio , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
19.
J Magn Reson Imaging ; 39(6): 1384-93, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24115554

RESUMO

PURPOSE: To demonstrate the feasibility of performing bone microarchitecture, high-resolution cartilage, and clinical imaging of the hip at 7T. MATERIALS AND METHODS: This study had Institutional Review Board approval. Using an 8-channel coil constructed in-house, we imaged the hips of 15 subjects on a 7T magnetic resonance imaging (MRI) scanner. We applied: 1) a T1-weighted 3D fast low angle shot (3D FLASH) sequence (0.23 × 0.23 × 1-1.5 mm(3) ) for bone microarchitecture imaging; 2) T1-weighted 3D FLASH (water excitation) and volumetric interpolated breath-hold examination (VIBE) sequences (0.23 × 0.23 × 1.5 mm(3) ) with saturation or inversion recovery-based fat suppression for cartilage imaging; 3) 2D intermediate-weighted fast spin-echo (FSE) sequences without and with fat saturation (0.27 × 0.27 × 2 mm) for clinical imaging. RESULTS: Bone microarchitecture images allowed visualization of individual trabeculae within the proximal femur. Cartilage was well visualized and fat was well suppressed on FLASH and VIBE sequences. FSE sequences allowed visualization of cartilage, the labrum (including cartilage and labral pathology), joint capsule, and tendons. CONCLUSION: This is the first study to demonstrate the feasibility of performing a clinically comprehensive hip MRI protocol at 7T, including high-resolution imaging of bone microarchitecture and cartilage, as well as clinical imaging.


Assuntos
Cartilagem Articular/patologia , Fêmur/patologia , Articulação do Quadril/patologia , Imageamento por Ressonância Magnética/métodos , Doenças Ósseas Metabólicas/patologia , Estudos de Viabilidade , Feminino , Humanos , Imageamento Tridimensional/métodos , Magnetismo , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
20.
Magn Reson Med ; 69(5): 1457-65, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-22714806

RESUMO

In ultra-high-field magnetic resonance imaging, parallel radiofrequency (RF) transmission presents both opportunities and challenges for specific absorption rate management. On one hand, parallel transmission provides flexibility in tailoring electric fields in the body while facilitating magnetization profile control. On the other hand, it increases the complexity of energy deposition as well as possibly exacerbating local specific absorption rate by improper design or delivery of RF pulses. This study shows that the information needed to characterize RF heating in parallel transmission is contained within a local power correlation matrix. Building upon a calibration scheme involving a finite number of magnetic resonance thermometry measurements, this work establishes a way of estimating the local power correlation matrix. Determination of this matrix allows prediction of temperature change for an arbitrary parallel transmit RF pulse. In the case of a three transmit coil MR experiment in a phantom, determination and validation of the power correlation matrix were conducted in less than 200 min with induced temperature changes of <4°C. Further optimization and adaptation are possible, and simulations evaluating potential feasibility for in vivo use are presented. The method allows general characteristics indicative of RF coil/pulse safety determined in situ.


Assuntos
Algoritmos , Temperatura Corporal/fisiologia , Temperatura Corporal/efeitos da radiação , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Modelos Biológicos , Termografia/métodos , Animais , Simulação por Computador , Relação Dose-Resposta à Radiação , Calefação/métodos , Humanos , Campos Magnéticos , Imageamento por Ressonância Magnética/instrumentação , Imagens de Fantasmas , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
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