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1.
Materials (Basel) ; 17(11)2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38893992

RESUMO

In order to facilitate the prediction of some physical properties, we propose several simple formulas based on two parameters only, the metallic valence and metallic atomic radii. Knowing the composition, for single-phase alloys, the average parameters can be calculated by the rule of mixture. The input parameters can be obtained from tabulated databases. Adopting from the literature the results of Coulomb crystal model for metals and single-phase high-entropy alloys, we have derived formulas for the shear modulus (G) and the cohesion energy (Ecoh). Based on these parameters separately, we set up two formulas to estimate the hardness in the case of pure metals. For single-phase (solid-solution) HEAs, by simplifying the Maresca and Curtin model, we obtained a formula for estimating the hardness, which takes into account the atomic misfit in addition to G. The maximal hardness for single-phase HEA is approximately 600 kg/mm2 and is obtained for a composition with a valence electron concentration of approximately 6 ÷ 7.

2.
J Neural Eng ; 21(3)2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38862007

RESUMO

Objective.Electrodes chronically implanted in the brain undergo complex changes over time that can lower the signal to noise ratio (SNR) of recorded signals and reduce the amount of energy delivered to the tissue during therapeutic stimulation, both of which are relevant for the development of robust, closed-loop control systems. Several factors have been identified that link changes in the electrode-tissue interface (ETI) to increased impedance and degraded performance in micro- and macro-electrodes. Previous studies have demonstrated that brief pulses applied every few days can restore SNR to near baseline levels during microelectrode recordings in rodents, a process referred to as electrical rejuvenation. However, electrical rejuvenation has not been tested in clinically relevant macroelectrode designs in large animal models, which could serve as preliminary data for translation of this technique. Here, several variations of this approach were tested to characterize parameters for optimization.Approach. Alternating-current (AC) and direct-current (DC) electrical rejuvenation methods were explored in three electrode types, chronically implanted in two adult male nonhuman primates (NHP) (Macaca mulatta), which included epidural electrocorticography (ECoG) electrodes and penetrating deep-brain stimulation (DBS) electrodes. Electrochemical impedance spectroscopy (EIS) was performed before and after each rejuvenation paradigm as a gold standard measure of impedance, as well as at subsequent intervals to longitudinally track the evolution of the ETI. Stochastic error modeling was performed to assess the standard deviation of the impedance data, and consistency with the Kramers-Kronig relations was assessed to evaluate the stationarity of EIS measurement.Main results. AC and DC rejuvenation were found to quickly reduce impedance and minimize the tissue component of the ETI on all three electrode types, with DC and low-frequency AC producing the largest impedance drops and reduction of the tissue component in Nyquist plots. The effects of a single rejuvenation session were found to last from several days to over 1 week, and all rejuvenation pulses induced no observable changes to the animals' behavior.Significance. These results demonstrate the effectiveness of electrical rejuvenation for diminishing the impact of chronic ETI changes in NHP with clinically relevant macroelectrode designs.


Assuntos
Eletrodos Implantados , Macaca mulatta , Animais , Masculino , Impedância Elétrica , Microeletrodos , Estimulação Elétrica/métodos , Estimulação Elétrica/instrumentação , Razão Sinal-Ruído
3.
Nature ; 629(8010): 80-85, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38693414

RESUMO

Building a fault-tolerant quantum computer will require vast numbers of physical qubits. For qubit technologies based on solid-state electronic devices1-3, integrating millions of qubits in a single processor will require device fabrication to reach a scale comparable to that of the modern complementary metal-oxide-semiconductor (CMOS) industry. Equally important, the scale of cryogenic device testing must keep pace to enable efficient device screening and to improve statistical metrics such as qubit yield and voltage variation. Spin qubits1,4,5 based on electrons in Si have shown impressive control fidelities6-9 but have historically been challenged by yield and process variation10-12. Here we present a testing process using a cryogenic 300-mm wafer prober13 to collect high-volume data on the performance of hundreds of industry-manufactured spin qubit devices at 1.6 K. This testing method provides fast feedback to enable optimization of the CMOS-compatible fabrication process, leading to high yield and low process variation. Using this system, we automate measurements of the operating point of spin qubits and investigate the transitions of single electrons across full wafers. We analyse the random variation in single-electron operating voltages and find that the optimized fabrication process leads to low levels of disorder at the 300-mm scale. Together, these results demonstrate the advances that can be achieved through the application of CMOS-industry techniques to the fabrication and measurement of spin qubit devices.

4.
Arch Clin Med Case Rep ; 7(1): 66-69, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36873804

RESUMO

Dysgerminoma is a rare malignant germ cell tumor of the ovary that often affects women in reproductive age. The presurgical differentiation of dysgerminoma from benign conditions is challenging. In early stages, malignant dysgerminoma can be treated with fertility sparing surgery. We present a pictorial non-systematic review of literature, discuss diagnostic challenges in ultrasound and radiological imaging and present laparoscopic treatment options in a young woman with dysgerminoma.

5.
Rev Sci Instrum ; 92(11): 115102, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34852535

RESUMO

The Comet Physics Laboratory (CoPhyLab) is an international research program to study the physical properties of cometary analog materials under simulated space conditions. The project is dedicated to studying, with the help of multiple instruments and the different expertise and background from the different partners, the physics of comets, including the processes inside cometary nuclei, the activity leading to the ejection of dust and gas, and the sub-surface and surface evolution of cometary nuclei when exposed to solar illumination. CoPhyLab will provide essential information on the formation and evolution of comets and insights into the origins of primitive Solar System bodies. To this end, we constructed a new laboratory that hosts several small-scale experiments and a large-scale comet-simulation chamber (L-Chamber). This chamber has been designed and constructed to host ice-dust samples with a diameter of up to 250 mm and a variable height between 100 and 300 mm. The cometary-analog samples will be kept at temperatures below 120 K and pressures around 10-6 mbar to ensure cometary-like conditions. In total, 14 different scientific instruments are attached to the L-Chamber to study the temporal evolution of the physical properties of the sample under different insolation conditions. Due to the implementation of a scale inside the L-Chamber that can measure weight changes of the samples with high precision, the cooling system is mechanically decoupled from the sample holder and cooling of the samples occurs by radiation only. The constructed chamber allows us to conduct uninterrupted experiments at low temperatures and pressures up to several weeks.

6.
FASEB J ; 34(11): 14671-14694, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32914503

RESUMO

Oxysterol-binding protein-related protein 2 (ORP2), a cholesterol-PI(4,5)P2 countercurrent transporter, was recently identified as a novel regulator of plasma membrane (PM) cholesterol and PI(4,5)P2 content in HeLa cells. Here, we investigate the role of ORP2 in endothelial cell (EC) cholesterol and PI(4,5)P2 distribution, angiogenic signaling, and angiogenesis. We show that ORP2 knock-down modifies the distribution of cholesterol accessible to a D4H probe, between late endosomes and the PM. Depletion of ORP2 from ECs inhibits their angiogenic tube formation capacity, alters the gene expression of angiogenic signaling pathways such as VEGFR2, Akt, mTOR, eNOS, and Notch, and reduces EC migration, proliferation, and cell viability. We show that ORP2 regulates the integrity of VEGFR2 at the PM in a cholesterol-dependent manner, the depletion of ORP2 resulting in proteolytic cleavage by matrix metalloproteinases, and reduced activity of VEGFR2 and its downstream signaling. We demonstrate that ORP2 depletion increases the PM PI(4,5)P2 coincident with altered F-actin morphology, and reduces both VEGFR2 and cholesterol in buoyant raft membranes. Moreover, ORP2 knock-down suppresses the expression of the lipid raft-associated proteins VE-cadherin and caveolin-1. Analysis of the retinal microvasculature in ORP2 knock-out mice generated during this study demonstrates the subtle alterations of morphology characterized by reduced vessel length and increased density of tip cells and perpendicular sprouts. Gene expression changes in the retina suggest disturbance of sterol homeostasis, downregulation of VE-cadherin, and a putative disturbance of Notch signaling. Our data identifies ORP2 as a novel regulator of EC cholesterol and PI(4,5)P2 homeostasis and cholesterol-dependent angiogenic signaling.


Assuntos
Células Endoteliais da Veia Umbilical Humana/metabolismo , Neovascularização Fisiológica , Receptores de Esteroides/metabolismo , Transdução de Sinais , Actinas/metabolismo , Antígenos CD/metabolismo , Caderinas/metabolismo , Caveolinas/metabolismo , Membrana Celular/metabolismo , Movimento Celular , Endossomos/metabolismo , Células Endoteliais da Veia Umbilical Humana/fisiologia , Humanos , Metaloproteinases da Matriz/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores Notch/metabolismo , Receptores de Esteroides/genética , Receptores de Fatores de Crescimento do Endotélio Vascular/metabolismo , Serina-Treonina Quinases TOR/metabolismo
7.
Pharmaceutics ; 12(8)2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32806740

RESUMO

Light-activated liposomes permit site and time-specific drug delivery to ocular and systemic targets. We combined a light activation technology based on indocyanine green with a hyaluronic acid (HA) coating by synthesizing HA-lipid conjugates. HA is an endogenous vitreal polysaccharide and a potential targeting moiety to cluster of differentiation 44 (CD44)-expressing cells. Light-activated drug release from 100 nm HA-coated liposomes was functional in buffer, plasma, and vitreous samples. The HA-coating improved stability in plasma compared to polyethylene glycol (PEG)-coated liposomes. Liposomal protein coronas on HA- and PEG-coated liposomes after dynamic exposure to undiluted human plasma and porcine vitreous samples were hydrophilic and negatively charged, thicker in plasma (~5 nm hard, ~10 nm soft coronas) than in vitreous (~2 nm hard, ~3 nm soft coronas) samples. Their compositions were dependent on liposome formulation and surface charge in plasma but not in vitreous samples. Compared to the PEG coating, the HA-coated liposomes bound more proteins in vitreous samples and enriched proteins related to collagen interactions, possibly explaining their slightly reduced vitreal mobility. The properties of the most abundant proteins did not correlate with liposome size or charge, but included proteins with surfactant and immune system functions in plasma and vitreous samples. The HA-coated light-activated liposomes are a functional and promising alternative for intravenous and ocular drug delivery.

8.
Adv Healthc Mater ; 9(17): e2000529, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32729247

RESUMO

Biohybrid nanosystems represent the cutting-edge research in biofunctionalization of micro- and nano-systems. Their physicochemical properties bring along advantages in the circulation time, camouflaging from the phagocytes, and novel antigens. This is partially a result of the qualitative differences in the protein corona, and the preferential targeting and uptake in homologous cells. However, the effect of the cell membrane on the cellular endocytosis mechanisms and time has not been fully evaluated yet. Here, the effect is assessed by quantitative flow cytometry analysis on the endocytosis of hydrophilic, negatively charged porous silicon nanoparticles and on their membrane-coated counterparts, in the presence of chemical inhibitors of different uptake pathways. Principal component analysis is used to analyze all the data and extrapolate patterns to highlight the cell-specific differences in the endocytosis mechanisms. Furthermore, the differences in the composition of static protein corona between naked and coated particles are investigated together with how these differences affect the interaction with human macrophages. Overall, the presence of the cell membrane only influences the speed and the entity of nanoparticles association with the cells, while there is no direct effect on the endocytosis pathways, composition of protein corona, or any reduction in macrophage-mediated uptake.


Assuntos
Nanopartículas , Coroa de Proteína , Membrana Celular , Endocitose , Humanos , Porosidade , Silício
9.
Nanoscale ; 12(3): 1728-1741, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31894806

RESUMO

Methodological constraints have limited our ability to study protein corona formation, slowing nanomedicine development and their successful translation into the clinic. We determined hard and soft corona structural properties along with the corresponding proteomic compositions on liposomes in a label-free workflow: surface plasmon resonance and a custom biosensor for in situ structure determination on liposomes and corona separation, and proteomics using sensitive nanoliquid chromatography tandem mass spectrometry with open-source bioinformatics platforms. Undiluted human plasma under dynamic flow conditions was used for in vivo relevance. Proof-of-concept is presented with a regular liposome formulation and two light-triggered indocyanine green (ICG) liposome formulations in preclinical development. We observed formulation-dependent differences in corona structure (thickness, protein-to-lipid ratio, and surface mass density) and protein enrichment. Liposomal lipids induced the enrichment of stealth-mediating apolipoproteins in the hard coronas regardless of pegylation, and their preferential enrichment in the soft corona of the pegylated liposome formulation with ICG was observed. This suggests that the soft corona of loosely interacting proteins contributes to the stealth properties as a component of the biological identity modulated by nanomaterial surface properties. The workflow addresses significant methodological gaps in biocorona research by providing truly complementary hard and soft corona compositions with corresponding in situ structural parameters for the first time. It has been designed into a convenient and easily reproducible single-experiment format suited for preclinical development of lipid nanomedicines.


Assuntos
Lipossomos/química , Nanopartículas/química , Coroa de Proteína/química , Humanos , Proteômica
10.
Nat Commun ; 10(1): 5747, 2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31848338

RESUMO

Virus-based cancer vaccines are nowadays considered an interesting approach in the field of cancer immunotherapy, despite the observation that the majority of the immune responses they elicit are against the virus and not against the tumor. In contrast, targeting tumor associated antigens is effective, however the identification of these antigens remains challenging. Here, we describe ExtraCRAd, a multi-vaccination strategy focused on an oncolytic virus artificially wrapped with tumor cancer membranes carrying tumor antigens. We demonstrate that ExtraCRAd displays increased infectivity and oncolytic effect in vitro and in vivo. We show that this nanoparticle platform controls the growth of aggressive melanoma and lung tumors in vivo both in preventive and therapeutic setting, creating a highly specific anti-cancer immune response. In conclusion, ExtraCRAd might serve as the next generation of personalized cancer vaccines with enhanced features over standard vaccination regimens, representing an alternative way to target cancer.


Assuntos
Vacinas Anticâncer/administração & dosagem , Imunoterapia/métodos , Neoplasias/terapia , Vírus Oncolíticos/imunologia , Vacinação/métodos , Adenoviridae/imunologia , Animais , Antígenos de Neoplasias/imunologia , Vacinas Anticâncer/imunologia , Linhagem Celular Tumoral/citologia , Linhagem Celular Tumoral/imunologia , Linhagem Celular Tumoral/transplante , Membrana Celular/imunologia , Modelos Animais de Doenças , Feminino , Humanos , Injeções Intralesionais , Camundongos , Nanopartículas/administração & dosagem , Neoplasias/imunologia , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto
11.
Science ; 365(6455): 817-820, 2019 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-31439797

RESUMO

The near-Earth asteroid (162173) Ryugu is a 900-m-diameter dark object expected to contain primordial material from the solar nebula. The Mobile Asteroid Surface Scout (MASCOT) landed on Ryugu's surface on 3 October 2018. We present images from the MASCOT camera (MASCam) taken during the descent and while on the surface. The surface is covered by decimeter- to meter-sized rocks, with no deposits of fine-grained material. Rocks appear either bright, with smooth faces and sharp edges, or dark, with a cauliflower-like, crumbly surface. Close-up images of a rock of the latter type reveal a dark matrix with small, bright, spectrally different inclusions, implying that it did not experience extensive aqueous alteration. The inclusions appear similar to those in carbonaceous chondrite meteorites.

12.
Nat Commun ; 10(1): 3391, 2019 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-31358770

RESUMO

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome that elevates the risk of hepatocellular carcinoma (HCC). Although alteration of lipid metabolism has been increasingly recognized as a hallmark of cancer cells, the deregulated metabolic modulation of HCC cells in the NAFLD progression remains obscure. Here, we discovers an endoplasmic reticulum-residential protein, Nogo-B, as a highly expressed metabolic modulator in both murine and human NAFLD-associated HCCs, which accelerates high-fat, high-carbohydrate diet-induced metabolic dysfunction and tumorigenicity. Mechanistically, CD36-mediated oxLDL uptake triggers CEBPß expression to directly upregulate Nogo-B, which interacts with ATG5 to promote lipophagy leading to lysophosphatidic acid-enhanced YAP oncogenic activity. This CD36-Nogo-B-YAP pathway consequently reprograms oxLDL metabolism and induces carcinogenetic signaling for NAFLD-associated HCCs. Targeting the Nogo-B pathway may represent a therapeutic strategy for HCC arising from the metabolic syndrome.


Assuntos
Autofagia , Carcinoma Hepatocelular/metabolismo , Lipoproteínas LDL/metabolismo , Neoplasias Hepáticas/metabolismo , Proteínas Nogo/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Animais , Carcinoma Hepatocelular/complicações , Carcinoma Hepatocelular/genética , Linhagem Celular Tumoral , Dieta Hiperlipídica/efeitos adversos , Retículo Endoplasmático/metabolismo , Feminino , Perfilação da Expressão Gênica/métodos , Células Hep G2 , Humanos , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/complicações , Neoplasias Hepáticas/genética , Síndrome Metabólica/etiologia , Síndrome Metabólica/genética , Síndrome Metabólica/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Nus , Proteínas Nogo/genética , Hepatopatia Gordurosa não Alcoólica/complicações , Hepatopatia Gordurosa não Alcoólica/genética , Transdução de Sinais/genética , Transplante Heterólogo
13.
Nat Commun ; 10(1): 2331, 2019 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-31133680

RESUMO

Artificial nanoparticles accumulate a protein corona layer in biological fluids, which significantly influences their bioactivity. As nanosized obligate intracellular parasites, viruses share many biophysical properties with artificial nanoparticles in extracellular environments and here we show that respiratory syncytial virus (RSV) and herpes simplex virus type 1 (HSV-1) accumulate a rich and distinctive protein corona in different biological fluids. Moreover, we show that corona pre-coating differentially affects viral infectivity and immune cell activation. In addition, we demonstrate that viruses bind amyloidogenic peptides in their corona and catalyze amyloid formation via surface-assisted heterogeneous nucleation. Importantly, we show that HSV-1 catalyzes the aggregation of the amyloid ß-peptide (Aß42), a major constituent of amyloid plaques in Alzheimer's disease, in vitro and in animal models. Our results highlight the viral protein corona as an acquired structural layer that is critical for viral-host interactions and illustrate a mechanistic convergence between viral and amyloid pathologies.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Herpesvirus Humano 1/patogenicidade , Interações Hospedeiro-Patógeno/imunologia , Fragmentos de Peptídeos/metabolismo , Coroa de Proteína/imunologia , Vírus Sincicial Respiratório Humano/patogenicidade , Doença de Alzheimer/imunologia , Doença de Alzheimer/patologia , Doença de Alzheimer/virologia , Animais , Líquido da Lavagem Broncoalveolar/virologia , Linhagem Celular Tumoral , Chlorocebus aethiops , Modelos Animais de Doenças , Feminino , Voluntários Saudáveis , Herpes Simples/sangue , Herpes Simples/imunologia , Herpes Simples/patologia , Herpesvirus Humano 1/imunologia , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Agregados Proteicos/imunologia , Infecções por Vírus Respiratório Sincicial/imunologia , Infecções por Vírus Respiratório Sincicial/patologia , Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Humano/imunologia , Células Vero
14.
Plant Dis ; 103(6): 1138-1147, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30939059

RESUMO

In western Colorado, Cytospora leucostoma is ubiquitous in peach orchards and has developed into a major limiting factor of peach production. The pathogen is unable to invade healthy intact phloem tissue of the tree, but instead, it requires a wound as a mode of entry. Bark injuries caused by cold and pruning in commercial orchard systems provide infection courts that, in suitable environment conditions, can lead to many successful fungal infections. Preventive fungicide control is an integral component of management in tree fruit production. Eighteen fungicides were tested at selected label dose rates for C. leucostoma control. All treatments were initially tested in vitro in fungicide-amended media dishes. Successful treatments were then tested under controlled conditions on detached peach branch segments. Effective fungicides identified in the laboratory assays (thiophanate-methyl, captan, lime sulfur, and copper hydroxide) were further tested as spray applications in the field and as wound sealant applications in combination with latex paint and kaolin clay. Of the treatments evaluated, thiophanate-methyl, captan, 50% latex paint, thiophanate-methyl amended in 50% latex paint, captan amended in 50% latex paint, and lime sulfur were most effective in reducing C. leucostoma necrotic area. Copper hydroxide was ineffective in all field trials and in some instances, yielded larger necrotic areas than the nontreated positive control shoots.


Assuntos
Ascomicetos , Fungicidas Industriais , Prunus persica , Ascomicetos/fisiologia , Colorado , Fungicidas Industriais/farmacologia , Doenças das Plantas/prevenção & controle , Prunus persica/microbiologia
15.
Nat Commun ; 10(1): 335, 2019 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-30659195

RESUMO

Hepatocellular carcinomas (HCC) exhibit distinct promoter hypermethylation patterns, but the epigenetic regulation and function of transcriptional enhancers remain unclear. Here, our affinity- and bisulfite-based whole-genome sequencing analyses reveal global enhancer hypomethylation in human HCCs. Integrative epigenomic characterization further pinpoints a recurrent hypomethylated enhancer of CCAAT/enhancer-binding protein-beta (C/EBPß) which correlates with C/EBPß over-expression and poorer prognosis of patients. Demethylation of C/EBPß enhancer reactivates a self-reinforcing enhancer-target loop via direct transcriptional up-regulation of enhancer RNA. Conversely, deletion of this enhancer via CRISPR/Cas9 reduces C/EBPß expression and its genome-wide co-occupancy with BRD4 at H3K27ac-marked enhancers and super-enhancers, leading to drastic suppression of driver oncogenes and HCC tumorigenicity. Hepatitis B X protein transgenic mouse model of HCC recapitulates this paradigm, as C/ebpß enhancer hypomethylation associates with oncogenic activation in early tumorigenesis. These results support a causal link between aberrant enhancer hypomethylation and C/EBPß over-expression, thereby contributing to hepatocarcinogenesis through global transcriptional reprogramming.


Assuntos
Carcinogênese/genética , Metilação de DNA , Neoplasias Hepáticas/genética , Sequências Reguladoras de Ácido Nucleico/genética , Animais , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Carcinoma Hepatocelular/genética , Proteínas de Ciclo Celular , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Desmetilação , Epigênese Genética , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Humanos , Fígado , Camundongos , Camundongos Transgênicos , Proteínas Nucleares/metabolismo , Prognóstico , Regiões Promotoras Genéticas , Transativadores , Fatores de Transcrição/metabolismo , Ativação Transcricional , Regulação para Cima , Proteínas Virais Reguladoras e Acessórias
16.
Neuropsychopharmacology ; 44(3): 590-597, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30375508

RESUMO

Cognitive control represents an essential neuropsychological characteristic that allows for the rapid adaption of a changing environment by constant re-allocation of cognitive resources. This finely tuned mechanism is impaired in psychiatric disorders such as schizophrenia and contributes to cognitive deficits. Neuroimaging has highlighted the contribution of the anterior cingulate cortex (ACC) and prefrontal regions (PFC) on cognitive control and demonstrated the impact of genetic variation, as well as genetic liability for schizophrenia. In this study, we aimed to examine the influence of the functional single-nucleotide polymorphism (SNP) rs6265 of a plasticity-related neurotrophic factor gene, BDNF (Val66Met), on cognitive control. Strong evidence implicates BDNF Val66Met in neural plasticity in humans. Furthermore, several studies suggest that although the variant is not convincingly associated with schizophrenia risk, it seems to be a modifier of the clinical presentation and course of the disease. In order to clarify the underlying mechanisms using functional magnetic resonance imaging (fMRI), we studied the effects of this SNP on ACC and PFC activation, and the connectivity between these regions in a discovery sample of 85 healthy individuals and sought to replicate this effect in an independent sample of 253 individuals. Additionally, we tested the identified imaging phenotype in relation to schizophrenia familial risk in a sample of 58 unaffected first-degree relatives of schizophrenia patients. We found a significant increase in interregional connectivity between ACC and PFC in the risk-associated BDNF 66Met allele carriers. Furthermore, we replicated this effect in an independent sample and demonstrated its independence of structural confounds, as well as task specificity. A similar coupling increase was detectable in individuals with increased familial risk for schizophrenia. Our results show that a key neural circuit for cognitive control is influenced by a plasticity-related genetic variant, which may render this circuit particular susceptible to genetic and environmental risk factors for schizophrenia.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/genética , Conectoma , Função Executiva/fisiologia , Giro do Cíngulo/fisiopatologia , Rede Nervosa/fisiopatologia , Plasticidade Neuronal/genética , Córtex Pré-Frontal/fisiopatologia , Esquizofrenia/genética , Adulto , Feminino , Predisposição Genética para Doença , Giro do Cíngulo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Córtex Pré-Frontal/diagnóstico por imagem , Adulto Jovem
17.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 3370-3373, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30441110

RESUMO

Whether via cuff or intrafascicular electrode, peripheral neural stimulations often rely on symmetric, charge balanced paradigms. To date, few investigations have been carried out which systematically decompose the features of a stimulus waveform. Factors such as pulse-width, amplitude, and the timing with which they are presented may have significant effects on the quality of the stimuli. This work seeks to fill this gap in knowledge and share insight into how selection of electrical stimuli may affect the resultant neural activation in peripheral nerves. In particular, we found that, although there is some variance, over the parameter range tested there was not a significant effect on neural fiber recruitment percent due to waveform selection.


Assuntos
Potenciais Evocados , Potenciais de Ação , Estimulação Elétrica , Nervos Periféricos , Recrutamento Neurofisiológico
18.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 5491-5494, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30441580

RESUMO

Bi-directional interfaces for peripheral nerve stimulation and recording aim to improve control and acceptance of sensorized prosthetic limbs. The implantable multimodal peripheral recording and stimulation system (IMPRESS) is an intraneural interface technology supporting a high-density transverse intrafascicular multichannel electrode (hd-TIME). Herein we report on in vivo selectivity studies using a passive hd-TIME, and computational modeling towards optimal stimulation parameters for fiber recruitment.


Assuntos
Nervos Periféricos , Estimulação Elétrica , Eletrodos Implantados , Desenho de Equipamento
19.
Eur J Neurol ; 25(4): 672-679, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29322594

RESUMO

BACKGROUND AND PURPOSE: The aim was to study the effects of rasagiline on sleep quality in patients with Parkinson's disease (PD) with sleep disturbances. Sleep disorders are common in PD. Rasagiline is widely used in patients with PD, but double-blind polysomnographic trials on its effects on sleep disturbances are missing. METHODS: This was a single-center, double-blind, baseline-controlled investigator-initiated clinical trial of rasagiline (1 mg/day) over 8 weeks in patients with PD with sleep disturbances. Blinding was achieved by running a strategic matched placebo parallel group. Co-primary outcome measures were the changes between baseline and end of the treatment period in sleep maintenance/efficiency as assessed by polysomnography and the Parkinson's Disease Sleep Scale Version 2 (PDSS-2) score. RESULTS: A total of 20 of 30 patients were randomized to rasagiline (mean ± SD age, 69.9 ± 6.9 years; 10 male; Hoehn-Yahr stage, 1.9 ± 0.8). Compared with baseline, sleep maintenance was significantly increased at the end of the treatment period (relative change normalized to baseline, +16.3 ± 27.9%; P = 0.024, paired two-sided t-test) and a positive trend for sleep efficiency was detected (+12.1 ± 28.6%; P = 0.097). Treatment with rasagiline led to significantly decreased wake time after sleep onset, number of arousals, percentage of light sleep and improved daytime sleepiness as measured by the Epworth Sleepiness Scale. We did not observe changes in the co-primary endpoint PDSS-2 score, and no correlations of polysomnographic sleep parameters or PDSS-2 score with motor function (Unified Parkinson's Disease Rating Scale motor score). Rasagiline was well tolerated with no unexpected adverse events. CONCLUSIONS: In patients with PD with sleep disturbances, rasagiline showed beneficial effects on sleep quality as measured by polysomnography. These effects were probably not related to motor improvement or translated into improved overall sleep quality perception by patients.


Assuntos
Indanos/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Doença de Parkinson/complicações , Polissonografia/efeitos dos fármacos , Transtornos do Sono-Vigília/complicações , Transtornos do Sono-Vigília/tratamento farmacológico , Sono/efeitos dos fármacos , Idoso , Idoso de 80 Anos ou mais , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
20.
J Hosp Infect ; 98(1): 83-89, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28797757

RESUMO

BACKGROUND: Transmission of microbes in the hospital environment occurs frequently through human interactions with high-touch surfaces such as patient beds and over-bed tables. Although stringent cleaning routines are implemented as a preventive measure to minimize transmission of microbes, it is desirable to have high-touch surfaces made of antimicrobial materials. Physical texturing of solid surfaces offers a non-bactericidal approach to control the colonization of such surfaces by microbes. AIM: To investigate the efficacy of micro-textured polycarbonate films in reducing bacterial load on over-bed tables in a hospital ward. METHODS: Two different micro-patterns were fabricated on polycarbonate film via a thermal imprinting method. Micro-textured films were then mounted on patient over-bed tables in a general hospital ward and the bacterial load monitored over 24 h. Total colony counts, which represented on-specific bacterial loading, and meticillin-resistant Staphylococcus aureus counts were monitored at each time-point. FINDINGS: Over a period of 24 h, both micro-textured surfaces showed consistently lower bacterial load as compared to the unpatterned polycarbonate and the bare over-bed table laminate. This study supports the findings of earlier laboratory-scale studies that microscale physical texturing can reduce bacterial colonization on a solid surface. CONCLUSION: Results of the current study suggest that micro-textured surfaces could provide a viable method for reducing microbial contamination of high-touch surfaces in hospitals.


Assuntos
Bactérias/isolamento & purificação , Descontaminação/métodos , Microbiologia Ambiental , Cimento de Policarboxilato , Propriedades de Superfície , Contagem de Colônia Microbiana , Hospitais
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