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1.
Nature ; 629(8010): 80-85, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38693414

RESUMEN

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.

2.
FASEB J ; 34(11): 14671-14694, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32914503

RESUMEN

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.


Asunto(s)
Células Endoteliales de la Vena Umbilical Humana/metabolismo , Neovascularización Fisiológica , Receptores de Esteroides/metabolismo , Transducción de Señal , Actinas/metabolismo , Antígenos CD/metabolismo , Cadherinas/metabolismo , Caveolinas/metabolismo , Membrana Celular/metabolismo , Movimiento Celular , Endosomas/metabolismo , Células Endoteliales de la Vena Umbilical Humana/fisiología , Humanos , Metaloproteinasas de la Matriz/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptores Notch/metabolismo , Receptores de Esteroides/genética , Receptores de Factores de Crecimiento Endotelial Vascular/metabolismo , Serina-Treonina Quinasas TOR/metabolismo
3.
Plant Dis ; 103(6): 1138-1147, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30939059

RESUMEN

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.


Asunto(s)
Ascomicetos , Fungicidas Industriales , Prunus persica , Ascomicetos/fisiología , Colorado , Fungicidas Industriales/farmacología , Enfermedades de las Plantas/prevención & control , Prunus persica/microbiología
4.
Eur J Neurol ; 25(4): 672-679, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29322594

RESUMEN

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.


Asunto(s)
Indanos/uso terapéutico , Fármacos Neuroprotectores/uso terapéutico , Enfermedad de Parkinson/complicaciones , Polisomnografía/efectos de los fármacos , Trastornos del Sueño-Vigilia/complicaciones , Trastornos del Sueño-Vigilia/tratamiento farmacológico , Sueño/efectos de los fármacos , Anciano , Anciano de 80 o más Años , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Resultado del Tratamiento
5.
Arch Orthop Trauma Surg ; 135(11): 1589-94, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26187600

RESUMEN

BACKGROUND AND PURPOSE: The aim of this study was to investigate the potential of MRI to determine rotational alignment after TKA in comparison to the gold standard, CT. METHODS: Rotational alignment was measured in the transverse plane on CT and MR-images in 14 patients prior to TKA revision. Differences between CT and MRI measurements were analysed. RESULTS: There was a strong correlation between CT and MRI measurements for both the tibial (r = 0.929) and femoral (r = 0.942) components with a mean difference of 0.47 ± 1.3 and 0.13 ± 3.2 degrees, respectively. INTERPRETATION: Despite artefact formation, it can be concluded that the rotational alignment of metallic TKA components can be measured by MRI as accurately as by CT.


Asunto(s)
Artroplastia de Reemplazo de Rodilla/métodos , Articulación de la Rodilla , Imagen por Resonancia Magnética , Rango del Movimiento Articular/fisiología , Humanos , Articulación de la Rodilla/diagnóstico por imagen , Articulación de la Rodilla/fisiología , Articulación de la Rodilla/fisiopatología , Articulación de la Rodilla/cirugía , Tomografía Computarizada por Rayos X
6.
J Therm Biol ; 44: 119-25, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25086982

RESUMEN

The endemic fish fauna of the Southern Ocean are cold-adapted stenotherms and are acutely sensitive to elevated temperature. Many of these species lack a heat shock response and cannot increase the production of heat shock proteins in their tissues. However, some species retain the ability to induce other stress-responsive genes, some of which are involved in cell cycle arrest and apoptosis. Here, the effect of heat on cell cycle stage and its ability to induce apoptosis were tested in thermally stressed hepatocytes from a common Antarctic fish species from McMurdo Sound in the Ross Sea. Levels of proliferating cell nuclear antigen were also measured as a marker of progression through the cell cycle. The results of these studies demonstrate that even sub-lethal heat stress can have deleterious impacts at the cellular level on these environmentally sensitive species.


Asunto(s)
Aclimatación , Apoptosis , Respuesta al Choque Térmico , Perciformes/fisiología , Animales , Regiones Antárticas , Proliferación Celular , Células Cultivadas , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Hepatocitos/metabolismo , Hepatocitos/fisiología , Antígeno Nuclear de Célula en Proliferación/genética , Antígeno Nuclear de Célula en Proliferación/metabolismo
7.
J Neural Eng ; 21(3)2024 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-38862007

RESUMEN

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.


Asunto(s)
Electrodos Implantados , Macaca mulatta , Animales , Masculino , Impedancia Eléctrica , Microelectrodos , Estimulación Eléctrica/métodos , Estimulación Eléctrica/instrumentación , Relación Señal-Ruido
8.
Materials (Basel) ; 17(11)2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38893992

RESUMEN

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.

9.
Int J Obes (Lond) ; 37(7): 931-6, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23032406

RESUMEN

OBJECTIVE: Although there is evidence of increasing prevalence of impaired glucose metabolism in obese children from smaller single cohorts, data are lacking on the progression of glucose metabolism in this patient group.We aimed to assess the prevalence and the longitudinal course of impaired glucose metabolism assessed by oral glucose tolerance test (oGTT) in a large multi-center pediatric obesity registry. SUBJECTS: We performed an observational multicenter (n=84) cross-sectional (n=11 156) and longitudinal analysis (n=1008) on the course of glucose metabolism evaluated by oGTT in obese children documented in the Adiposity Patients Verlaufsbeobachtung (APV) registry. Patients were stratified with impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and Type 2 diabetes (T2D), according to American Diabetes Association criteria. RESULTS: A total of 12.6% of the children presented with abnormal glucose metabolism (5.99% IFG, 5.51% IGT, 1.07% T2D). Body mass index (BMI) correlated modestly with 2-h blood glucose (r=0.04, P<0.001).In the 1008 patients with follow-up oGTT, metabolic parameters improved and the percentage of abnormal glucose metabolism decreased from 18.7 to 14.2%. Of the children with initial IGT, 70.6% converted to normal glucose tolerance. The improvement in oGTT results was associated with, but not dependent on, a reduction of BMI s.d. score. CONCLUSION: In summary, we provide evidence for significant improvement of oGTT parameters in obese children treated in specialized treatment centers, even though reduction in BMI was modest.


Asunto(s)
Glucemia/metabolismo , Enfermedades Cardiovasculares/prevención & control , Diabetes Mellitus Tipo 2/metabolismo , Obesidad Infantil/metabolismo , Adolescente , Índice de Masa Corporal , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/metabolismo , Niño , Estudios Transversales , Diabetes Mellitus Tipo 2/epidemiología , Diabetes Mellitus Tipo 2/prevención & control , Femenino , Alemania/epidemiología , Intolerancia a la Glucosa , Prueba de Tolerancia a la Glucosa , Humanos , Resistencia a la Insulina , Estudios Longitudinales , Masculino , Cooperación del Paciente , Obesidad Infantil/epidemiología , Obesidad Infantil/prevención & control , Prevalencia , Sistema de Registros , Pérdida de Peso
10.
Acta Oncol ; 52(3): 636-44, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23075421

RESUMEN

INTRODUCTION: Our primary aim was to make a phantom for PET that could mimic a highly irregular tumour and provide true tumour contours. The secondary aim was to use the phantom to assess the accuracy of different methods for delineation of tumour volume from the PET images. MATERIAL AND METHODS: An empty mould was produced on the basis of a contrast enhanced computed tomography (CT) study of a patient with a squamous cell carcinoma in the head and neck region. The mould was filled with a homogeneous fast-settling gel that contained both (18)F for positron emission tomography (PET) and an iodine contrast agent. This phantom (mould and gel) was scanned on a PET/CT scanner. A series of reference tumour contours were obtained from the CT images in the PET/CT. Tumour delineation based on the PET images was achieved manually, by isoSUV thresholding, and by a recently developed three-dimensional (3D) Difference of Gaussians algorithm (DoG). Average distances between the PET-derived and reference contours were assessed by a 3D distance transform. RESULTS: The manual, thresholding and DoG delineation methods resulted in volumes that were 146%, 86% and 100% of the reference volume, respectively, and average distance deviations from the reference surface were 1.57 mm, 1.48 mm and 1.0, mm, respectively. DISCUSSION: Manual drawing as well as isoSUV determination of tumour contours in geometrically irregular tumours may be unreliable. The DoG method may contribute to more correct delineation of the tumour. Although the present phantom had a homogeneous distribution of activity, it may also provide useful knowledge in the case of inhomogeneous activity distributions. CONCLUSION: The geometric irregular tumour phantom with its inherent reference contours was an important tool for testing of different delineation methods and for teaching delineation.


Asunto(s)
Geles , Imagen Multimodal/métodos , Neoplasias/diagnóstico por imagen , Neoplasias/patología , Fantasmas de Imagen , Tomografía de Emisión de Positrones , Planificación de la Radioterapia Asistida por Computador/métodos , Tomografía Computarizada por Rayos X , Algoritmos , Carcinoma de Células Escamosas/diagnóstico por imagen , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/radioterapia , Fluorodesoxiglucosa F18 , Neoplasias de Cabeza y Cuello/diagnóstico por imagen , Neoplasias de Cabeza y Cuello/patología , Neoplasias de Cabeza y Cuello/radioterapia , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Modelos Anatómicos , Modelos Biológicos , Neoplasias/radioterapia , Reconocimiento de Normas Patrones Automatizadas/métodos , Planificación de la Radioterapia Asistida por Computador/instrumentación , Carcinoma de Células Escamosas de Cabeza y Cuello , Carga Tumoral/fisiología
11.
Nat Genet ; 26(1): 64-6, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10973250

RESUMEN

A major obstacle to stem-cell gene therapy rests in the inability to deliver a gene into a therapeutically relevant fraction of stem cells. One way to circumvent this obstacle is to use selection. Vectors containing two linked genes serve as the basis for selection, with one gene encoding a selectable product and the other, a therapeutic protein. Applying selection in vivo has the potential to bring a minor population of genetically corrected cells into the therapeutic range. But strategies for achieving in vivo selection have traditionally relied on genes that confer resistance to cytotoxic drugs and are encumbered by toxicity. Here we describe a new system for in vivo selection that uses a 'cell-growth switch', allowing a minor population of genetically corrected cells into the therapeutic range. But strategies for achieving in vivo selection have traditionally relied on genes that confer resistance to cytotoxic drugs and are encumbered by toxicity. Here we describe a new system for in vivo selection that uses a 'cell-growth switch', allowing a minor population of genetically modified cells to be inducibly amplified, thereby averting the risks associated with cytotoxic drugs. This system provides a general platform for conditionally expanding genetically modified cell populations in vivo, and may have widespread applications in gene and cell therapy.


Asunto(s)
Separación Celular , Terapia Genética/métodos , Vectores Genéticos , Proteínas de Neoplasias , Receptores de Citocinas , Animales , Plaquetas/citología , Plaquetas/metabolismo , Southern Blotting , Trasplante de Médula Ósea , Técnicas de Cultivo de Célula/métodos , Dimerización , Relación Dosis-Respuesta a Droga , Eritrocitos/citología , Eritrocitos/metabolismo , Citometría de Flujo , Granulocitos/citología , Granulocitos/metabolismo , Proteínas Fluorescentes Verdes , Cinética , Proteínas Luminiscentes/metabolismo , Ratones , Proteínas Oncogénicas/química , Proteínas Oncogénicas/metabolismo , Fenotipo , Estructura Terciaria de Proteína , Proteínas Proto-Oncogénicas/química , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-kit , Receptores de Eritropoyetina/química , Receptores de Eritropoyetina/metabolismo , Receptores de Trombopoyetina , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Retroviridae/genética , Factores de Tiempo , Transgenes
12.
Arch Clin Med Case Rep ; 7(1): 66-69, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36873804

RESUMEN

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.

13.
Eur Arch Otorhinolaryngol ; 269(7): 1783-9, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22159965

RESUMEN

The skin adhesive Histoacryl(®) consists of n-butyl-2-cyanoacrylate which polymerises in contact with moisture. It is not fully biodegradable, produces heat during polymerisation and releases products which are toxic and inhibit cell growth. Clinical application is exclusively approved to glue skin. However, there are also clinical studies and case reports in the scientific literature, which discuss the application of Histoacryl(®) as a soft tissue adhesive. In parallel to an analysis of the literature which discusses the usage of Histoacryl(®) in head and neck surgery, we performed in vitro and in vivo investigations with this adhesive. In vitro, the vitality of cultured cell lines which where treated with extracts of Histoacryl(®) was determined with a viability assay. In addition, Histoacryl(®) was examined by fixing defined mucous membrane of the nasal septum in an animal study in rabbits. The analysis of the literature shows both positive and negative results for the application of Histoacryl(®) as a soft tissue adhesive depending on the manner and place of the application as well as the applied amount of glue. Our own results confirm a negative influence of Histoacryl(®) on the viability of cultured cells and soft tissue. The histological examination showed that a better biocompatibility is achieved if the glue is used in small amounts. Both the literature study as well as the in vitro and in vivo examinations showed that the usage of Histoacryl(®) as a soft tissue glue may be arguable. Critical factors are the moisture at the application area and the applied amount of glue.


Asunto(s)
Enbucrilato/farmacología , Mucosa Nasal , Cicatrización de Heridas/efectos de los fármacos , Adhesivos/farmacología , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Femenino , Ensayo de Materiales/métodos , Ratones , Modelos Animales , Mucosa Nasal/efectos de los fármacos , Mucosa Nasal/patología , Conejos , Adhesivos Tisulares/farmacología , Resultado del Tratamiento
14.
Rev Sci Instrum ; 92(11): 115102, 2021 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-34852535

RESUMEN

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.

15.
Nanoscale ; 12(3): 1728-1741, 2020 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-31894806

RESUMEN

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.


Asunto(s)
Liposomas/química , Nanopartículas/química , Corona de Proteínas/química , Humanos , Proteómica
16.
Pharmaceutics ; 12(8)2020 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-32806740

RESUMEN

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.

17.
Adv Healthc Mater ; 9(17): e2000529, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32729247

RESUMEN

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.


Asunto(s)
Nanopartículas , Corona de Proteínas , Membrana Celular , Endocitosis , Humanos , Porosidad , Silicio
18.
Clin Oncol (R Coll Radiol) ; 21(5): 401-7, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19268554

RESUMEN

AIMS: Volumetric modulated arc therapy (VMAT) is a novel extension of intensity-modulated radiotherapy (IMRT) where an optimised three-dimensional dose distribution may be delivered in a single gantry rotation. This optimisation algorithm is the predecessor to Varian's RapidArc. The aim of this study was to compare the ability of conventional static nine-field IMRT (cIMRT) and VMAT to boost as much of the clinical target volume (CTV) as possible to 88.8Gy without exceeding organ at risk (OAR) dose-volume constraints. MATERIALS AND METHODS: Optimal cIMRT and VMAT radiotherapy plans were produced for 10 patients with localised prostate cancer using common planning objectives: (1) Treat >or=98% of the planning target volume (PTV) to >or=95% of the prescription dose (74Gy in 37 fractions); (2) keep OAR doses within predefined limits; (3) treat as much of prostate CTV (minus urethra) as possible to >or=120% of prescription dose (=88.8Gy); (4) keep within maximum dose limits in and out of target volumes; (5) conformality index (volume of 95% isodose/volume of PTV)or=120% of the prescription dose (P=0.002). All dose constraints were kept within predefined limits. VMAT and cIMRT required an average of 949 and 1819 monitor units and 3.7 and 9.6min, respectively, to deliver a single radiation fraction. CONCLUSIONS: VMAT is able to boost more of the CTV to >or=120% than cIMRT without contravening OAR dose constraints, and uses 48% fewer monitor units. Treatment times were 61% less than with cIMRT.


Asunto(s)
Neoplasias de la Próstata/radioterapia , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada/métodos , Fraccionamiento de la Dosis de Radiación , Humanos , Masculino , Análisis por Apareamiento , Radioterapia de Intensidad Modulada/instrumentación , Carga Tumoral
19.
Neuropsychopharmacology ; 44(3): 590-597, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30375508

RESUMEN

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.


Asunto(s)
Factor Neurotrófico Derivado del Encéfalo/genética , Conectoma , Función Ejecutiva/fisiología , Giro del Cíngulo/fisiopatología , Red Nerviosa/fisiopatología , Plasticidad Neuronal/genética , Corteza Prefrontal/fisiopatología , Esquizofrenia/genética , Adulto , Femenino , Predisposición Genética a la Enfermedad , Giro del Cíngulo/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Corteza Prefrontal/diagnóstico por imagen , Adulto Joven
20.
Nat Commun ; 10(1): 5747, 2019 12 17.
Artículo en Inglés | MEDLINE | ID: mdl-31848338

RESUMEN

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.


Asunto(s)
Vacunas contra el Cáncer/administración & dosificación , Inmunoterapia/métodos , Neoplasias/terapia , Virus Oncolíticos/inmunología , Vacunación/métodos , Adenoviridae/inmunología , Animales , Antígenos de Neoplasias/inmunología , Vacunas contra el Cáncer/inmunología , Línea Celular Tumoral/citología , Línea Celular Tumoral/inmunología , Línea Celular Tumoral/trasplante , Membrana Celular/inmunología , Modelos Animales de Enfermedad , Femenino , Humanos , Inyecciones Intralesiones , Ratones , Nanopartículas/administración & dosificación , Neoplasias/inmunología , Resultado del Tratamiento , Ensayos Antitumor por Modelo de Xenoinjerto
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