Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 100
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Chem Soc Rev ; 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38912871

RESUMO

Ionic liquids (ILs) and deep eutectic solvents (DESs) have tremendous potential for reactive capture and conversion (RCC) of CO2 due to their wide electrochemical stability window, low volatility, and high CO2 solubility. There is environmental and economic interest in the direct utilization of the captured CO2 using electrified and modular processes that forgo the thermal- or pressure-swing regeneration steps to concentrate CO2, eliminating the need to compress, transport, or store the gas. The conventional electrochemical conversion of CO2 with aqueous electrolytes presents limited CO2 solubility and high energy requirement to achieve industrially relevant products. Additionally, aqueous systems have competitive hydrogen evolution. In the past decade, there has been significant progress toward the design of ILs and DESs, and their composites to separate CO2 from dilute streams. In parallel, but not necessarily in synergy, there have been studies focused on a few select ILs and DESs for electrochemical reduction of CO2, often diluting them with aqueous or non-aqueous solvents. The resulting electrode-electrolyte interfaces present a complex speciation for RCC. In this review, we describe how the ILs and DESs are tuned for RCC and specifically address the CO2 chemisorption and electroreduction mechanisms. Critical bulk and interfacial properties of ILs and DESs are discussed in the context of RCC, and the potential of these electrolytes are presented through a techno-economic evaluation.

2.
Langmuir ; 40(18): 9426-9438, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38441476

RESUMO

Ionic liquids (ILs) are considered functional electrolytes for the electrocatalytic reduction of CO2 (ECO2R) due to their role in the double-layer structure formation and increased CO2 availability at the electrode surface, which reduces the voltage requirement. However, not all ILs are the same, considering the purity and degree of the functionality of the IL. Further, there are critical experimental factors that impact the evaluation of ILs for ECO2R including the reference electrode, working electrode construction, cosolvent selection, cell geometry, and whether the electrochemical cell is a single compartment or a divided cell. Here, we describe improved synthesis methods of imidazolium cyanopyrrolide IL for electrochemical studies in consideration of precursor composition and reaction time. We explored how IL with cosolvents (i.e. acetonitrile, dimethylformamide, dimethyl sulfoxide, propylene carbonate, and n-methyl-2-pyrrolidone) affects conductivity, CO2 mass transport, and ECO2R activation overpotential together with the effects of electrode materials (Sn, Ag, Au, and glassy carbon). Acetonitrile was found to be the best solvent for lowering the onset potential and increasing the catalytic current density for the production of CO owing to the enhanced ion mobility in combination with the silver electrode. Further, the ECO2R activity of molecular catalysts Ni(cyclam)Cl2 and iron tetraphenylsulfonato porphyrin (FeTPPS) on the carbon cloth electrode maintained high Faradaic efficiencies for CO in the presence of the IL. This study presents best practices for examining nontraditional multifunctional electrolytes amenable to integrated CO2 capture and conversion technologies for homogeneous and heterogeneous ECO2R.

3.
Dev Dyn ; 252(5): 605-628, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36606464

RESUMO

BACKGROUND: Fibrodysplasia ossificans progressiva (FOP), a rare disease characterized by progressive heterotopic ossification of muscle and connective tissues, is caused by autosomal dominant activating mutations in the type I receptor, ACVR1/ALK2. The classic human FOP variant, ACVR1R206H , shows increased bone morphogenetic protein (BMP) signaling and activation by activins. RESULTS: Here, we performed in vivo functional characterization of human ACVR1R206H and orthologous zebrafish Acvr1lR203H using early embryonic zebrafish dorsoventral patterning as a phenotypic readout for receptor activity. Our results showed that human ACVR1R206H and zebrafish Acvr1lR203H exhibit functional differences in early embryonic zebrafish, and that human ACVR1R206H retained its signaling activity in the absence of a ligand-binding domain (LBD). We also showed, for the first time, that zebrafish Acvr2ba/Acvr2bb receptors are required for human ACVR1R206H signaling in early embryonic zebrafish. CONCLUSIONS: Together, these data provide new insight into ACVR1R206H signaling pathways that may facilitate the design of new and effective therapies for FOP patients.


Assuntos
Receptores de Ativinas Tipo I , Embrião não Mamífero , Miosite Ossificante , Ossificação Heterotópica , Animais , Humanos , Receptores de Ativinas Tipo I/genética , Mutação , Transdução de Sinais , Peixe-Zebra , Embrião não Mamífero/metabolismo
4.
Am J Physiol Lung Cell Mol Physiol ; 324(4): L400-L412, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36807882

RESUMO

Muscle atrophy is an extrapulmonary complication of acute exacerbations (AE) in chronic obstructive pulmonary disease (COPD). The endogenous production and therapeutic application of glucocorticoids (GCs) have been implicated as drivers of muscle loss in AE-COPD. The enzyme 11 ß-hydroxysteroid dehydrogenase 1 (11ß-HSD1) activates GCs and contributes toward GC-induced muscle wasting. To explore the potential of 11ßHSD1 inhibition to prevent muscle wasting here, the objective of this study was to ascertain the contribution of endogenous GC activation and amplification by 11ßHSD1 in skeletal muscle wasting during AE-COPD. Emphysema was induced by intratracheal (IT) instillation of elastase to model COPD in WT and 11ßHSD1/KO mice, followed by vehicle or IT-LPS administration to mimic AE. µCT scans were obtained prior and at study endpoint 48 h following IT-LPS, to assess emphysema development and muscle mass changes, respectively. Plasma cytokine and GC profiles were determined by ELISA. In vitro, myonuclear accretion and cellular response to plasma and GCs were determined in C2C12 and human primary myotubes. Muscle wasting was exacerbated in LPS-11ßHSD1/KO animals compared with WT controls. RT-qPCR and western blot analysis showed elevated catabolic and suppressed anabolic pathways in muscle of LPS-11ßHSD1/KO animals relative to WTs. Plasma corticosterone levels were higher in LPS-11ßHSD1/KO animals, whereas C2C12 myotubes treated with LPS-11ßHSD1/KO plasma or exogenous GCs displayed reduced myonuclear accretion relative to WT counterparts. This study reveals that 11ß-HSD1 inhibition aggravates muscle wasting in a model of AE-COPD, suggesting that therapeutic inhibition of 11ß-HSD1 may not be appropriate to prevent muscle wasting in this setting.


Assuntos
11-beta-Hidroxiesteroide Desidrogenase Tipo 1 , Enfisema , Doença Pulmonar Obstrutiva Crônica , Animais , Humanos , Camundongos , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/metabolismo , Glucocorticoides/farmacologia , Lipopolissacarídeos , Atrofia Muscular/etiologia , Atrofia Muscular/metabolismo , Atrofia Muscular/prevenção & controle , Doença Pulmonar Obstrutiva Crônica/complicações
5.
PLoS Biol ; 18(11): e3000917, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33180788

RESUMO

The transition from mitosis into the first gap phase of the cell cycle in budding yeast is controlled by the Mitotic Exit Network (MEN). The network interprets spatiotemporal cues about the progression of mitosis and ensures that release of Cdc14 phosphatase occurs only after completion of key mitotic events. The MEN has been studied intensively; however, a unified understanding of how localisation and protein activity function together as a system is lacking. In this paper, we present a compartmental, logical model of the MEN that is capable of representing spatial aspects of regulation in parallel to control of enzymatic activity. We show that our model is capable of correctly predicting the phenotype of the majority of mutants we tested, including mutants that cause proteins to mislocalise. We use a continuous time implementation of the model to demonstrate that Cdc14 Early Anaphase Release (FEAR) ensures robust timing of anaphase, and we verify our findings in living cells. Furthermore, we show that our model can represent measured cell-cell variation in Spindle Position Checkpoint (SPoC) mutants. This work suggests a general approach to incorporate spatial effects into logical models. We anticipate that the model itself will be an important resource to experimental researchers, providing a rigorous platform to test hypotheses about regulation of mitotic exit.


Assuntos
Ciclo Celular/genética , Pontos de Checagem da Fase M do Ciclo Celular/fisiologia , Ciclo Celular/fisiologia , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/fisiologia , Divisão do Núcleo Celular/fisiologia , Pontos de Checagem da Fase M do Ciclo Celular/genética , Mitose/fisiologia , Fosforilação , Proteínas Tirosina Fosfatases/genética , Proteínas Tirosina Fosfatases/metabolismo , Proteínas Tirosina Fosfatases/fisiologia , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/fisiologia , Saccharomycetales/genética , Saccharomycetales/metabolismo , Fuso Acromático/fisiologia
6.
BMC Bioinformatics ; 23(1): 60, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-35123390

RESUMO

BACKGROUND: Colony growth on solid media is a simple and effective measure for high-throughput genomic experiments such as yeast two-hybrid, synthetic dosage lethality and Synthetic Physical Interaction screens. The development of robotic pinning tools has facilitated the experimental design of these assays, and different imaging software can be used to automatically measure colony sizes on plates. However, comparison to control plates and statistical data analysis is often laborious and pinning issues or plate specific growth effects can lead to the detection of false-positive growth defects. RESULTS: We have developed ScreenGarden, a shinyR application, to enable easy, quick and robust data analysis of plate-based high throughput assays. The code allows comparisons of different formats of data and different sized arrays of colonies. A comparison of ScreenGarden with previous analysis tools shows that it performs, at least, equivalently. The software can be run either via a website or offline via the RStudio program; the code is available and can be modified by expert uses to customise the analysis. CONCLUSIONS: ScreenGarden provides a simple, fast and effective tool to analyse colony growth data from genomic experiments.


Assuntos
Genômica , Software , Meios de Cultura , Ensaios de Triagem em Larga Escala , Saccharomyces cerevisiae
7.
Nature ; 531(7596): 614-7, 2016 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-27029276

RESUMO

The ability to measure tiny variations in the local gravitational acceleration allows, besides other applications, the detection of hidden hydrocarbon reserves, magma build-up before volcanic eruptions, and subterranean tunnels. Several technologies are available that achieve the sensitivities required for such applications (tens of microgal per hertz(1/2)): free-fall gravimeters, spring-based gravimeters, superconducting gravimeters, and atom interferometers. All of these devices can observe the Earth tides: the elastic deformation of the Earth's crust as a result of tidal forces. This is a universally predictable gravitational signal that requires both high sensitivity and high stability over timescales of several days to measure. All present gravimeters, however, have limitations of high cost (more than 100,000 US dollars) and high mass (more than 8 kilograms). Here we present a microelectromechanical system (MEMS) device with a sensitivity of 40 microgal per hertz(1/2) only a few cubic centimetres in size. We use it to measure the Earth tides, revealing the long-term stability of our instrument compared to any other MEMS device. MEMS accelerometers--found in most smart phones--can be mass-produced remarkably cheaply, but none are stable enough to be called a gravimeter. Our device has thus made the transition from accelerometer to gravimeter. The small size and low cost of this MEMS gravimeter suggests many applications in gravity mapping. For example, it could be mounted on a drone instead of low-flying aircraft for distributed land surveying and exploration, deployed to monitor volcanoes, or built into multi-pixel density-contrast imaging arrays.

8.
Int J Mol Sci ; 23(13)2022 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-35806338

RESUMO

Therapeutic glucocorticoids (GCs) are powerful anti-inflammatory tools in the management of chronic inflammatory diseases such as rheumatoid arthritis (RA). However, their actions on bone in this context are complex. The enzyme 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) is a mediator of the anti-inflammatory actions of therapeutic glucocorticoids (GCs) in vivo. In this study we delineate the role of 11ß-HSD1 in the effects of GC on bone during inflammatory polyarthritis. Its function was assessed in bone biopsies from patients with RA and osteoarthritis, and in primary osteoblasts and osteoclasts. Bone metabolism was assessed in the TNF-tg model of polyarthritis treated with oral GC (corticosterone), in animals with global (TNF-tg11ßKO), mesenchymal (including osteoblast) (TNF-tg11ßflx/tw2cre) and myeloid (including osteoclast) (TNF-tg11ßflx/LysMcre) deletion. Bone parameters were assessed by micro-CT, static histomorphometry and serum metabolism markers. We observed a marked increase in 11ß-HSD1 activity in bone in RA relative to osteoarthritis bone, whilst the pro-inflammatory cytokine TNFα upregulated 11ß-HSD1 within osteoblasts and osteoclasts. In osteoclasts, 11ß-HSD1 mediated the suppression of bone resorption by GCs. Whilst corticosterone prevented the inflammatory loss of trabecular bone in TNF-tg animals, counterparts with global deletion of 11ß-HSD1 were resistant to these protective actions, characterised by increased osteoclastic bone resorption. Targeted deletion of 11ß-HSD1 within osteoclasts and myeloid derived cells partially reproduced the GC resistant phenotype. These data reveal the critical role of 11ß-HSD1 within bone and osteoclasts in mediating the suppression of inflammatory bone loss in response to therapeutic GCs in chronic inflammatory disease.


Assuntos
Artrite Reumatoide , Reabsorção Óssea , Osteoartrite , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/genética , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/metabolismo , Animais , Artrite Reumatoide/metabolismo , Reabsorção Óssea/metabolismo , Corticosterona/metabolismo , Glucocorticoides/metabolismo , Glucocorticoides/farmacologia , Inflamação/patologia , Osteoartrite/metabolismo , Osteoclastos/metabolismo
9.
Ann Rheum Dis ; 80(2): 250-260, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33162397

RESUMO

OBJECTIVES: The enzyme 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) plays a well-characterised role in the metabolism and activation of endogenous glucocorticoids (GCs). However, despite its potent upregulation at sites of inflammation, its role in peripheral metabolism and action of therapeutic GCs remains poorly understood. We investigated the contribution of 11ß-HSD1 to the anti-inflammatory properties of the active GC corticosterone, administered at therapeutic doses in murine models of polyarthritis. METHODS: Using the tumour necrosis factor-tg and K/BxN serum-induced models of polyarthritis, we examined the anti-inflammatory properties of oral administration of corticosterone in animals with global, myeloid and mesenchymal targeted transgenic deletion of 11ß-HSD1. Disease activity and joint inflammation were scored daily. Joint destruction and measures of local and systemic inflammation were determined by histology, micro-CT, quantitative RT-PCR, fluorescence activated cell sorting and ELISA. RESULTS: Global deletion of 11ß-HSD1 resulted in a profound GC resistance in animals receiving corticosterone, characterised by persistent synovitis, joint destruction and inflammatory leucocyte infiltration. This was partially reproduced with myeloid, but not mesenchymal 11ß-HSD1 deletion, where paracrine GC signalling between cell populations was shown to overcome targeted deletion of 11ß-HSD1. CONCLUSIONS: We identify an entirely novel component of therapeutic GC action, whereby following their systemic metabolism, they require peripheral reactivation and amplification by 11ß-HSD1 at sites of inflammation to deliver their anti-inflammatory therapeutic effects. This study provides a novel mechanistic understanding of the anti-inflammatory properties of therapeutic GCs and their targeting to sites of inflammation in polyarthritis.


Assuntos
11-beta-Hidroxiesteroide Desidrogenase Tipo 1/metabolismo , Anti-Inflamatórios/farmacologia , Artrite/tratamento farmacológico , Corticosterona/farmacologia , Glucocorticoides/farmacologia , Animais , Artrite/enzimologia , Modelos Animais de Doenças , Camundongos
10.
Opt Express ; 29(12): 18059-18069, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34154073

RESUMO

Silicate bonding is a flexible bonding method that enables room-temperature bonding of many types of materials with only moderate flatness constraints. It is a promising approach for bonding components in high power laser systems, since it results in a thin and low-absorption interface layer between the bonded materials. Here we demonstrate for the first time silicate bonding of a sapphire window to a SEmiconductor Saturable Absorber Mirror (SESAM) and use the composite structure to mode-lock a high-power thin-disk laser. We characterize the fabricated devices both theoretically and experimentally and show how the thermally induced lens of the composite structure can be tuned both in magnitude and sign via the thickness of the sapphire window. We demonstrate mode-locking of a high-power thin-disk laser oscillator with these devices. The altered thermal lens allows us to increase the output power to 233 W, a 70-W-improvement compared to the results achieved with a state-of-the-art SESAM in the same cavity.

11.
Int J Mol Sci ; 22(15)2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34360594

RESUMO

Glucocorticoids provide indispensable anti-inflammatory therapies. However, metabolic adverse effects including muscle wasting restrict their use. The enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) modulates peripheral glucocorticoid responses through pre-receptor metabolism. This study investigates how 11ß-HSD1 influences skeletal muscle responses to glucocorticoid therapy for chronic inflammation. We assessed human skeletal muscle biopsies from patients with rheumatoid arthritis and osteoarthritis for 11ß-HSD1 activity ex vivo. Using the TNF-α-transgenic mouse model (TNF-tg) of chronic inflammation, we examined the effects of corticosterone treatment and 11ß-HSD1 global knock-out (11ßKO) on skeletal muscle, measuring anti-inflammatory gene expression, muscle weights, fiber size distribution, and catabolic pathways. Muscle 11ß-HSD1 activity was elevated in patients with rheumatoid arthritis and correlated with inflammation markers. In murine skeletal muscle, glucocorticoid administration suppressed IL6 expression in TNF-tg mice but not in TNF-tg11ßKO mice. TNF-tg mice exhibited reductions in muscle weight and fiber size with glucocorticoid therapy. In contrast, TNF-tg11ßKO mice were protected against glucocorticoid-induced muscle atrophy. Glucocorticoid-mediated activation of catabolic mediators (FoxO1, Trim63) was also diminished in TNF-tg11ßKO compared to TNF-tg mice. In summary, 11ß-HSD1 knock-out prevents muscle atrophy associated with glucocorticoid therapy in a model of chronic inflammation. Targeting 11ß-HSD1 may offer a strategy to refine the safety of glucocorticoids.


Assuntos
11-beta-Hidroxiesteroide Desidrogenase Tipo 1/genética , Artrite Reumatoide/tratamento farmacológico , Deleção de Genes , Glucocorticoides/efeitos adversos , Atrofia Muscular/prevenção & controle , Osteoartrite do Quadril/tratamento farmacológico , Animais , Artrite Reumatoide/patologia , Modelos Animais de Doenças , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Atrofia Muscular/induzido quimicamente , Atrofia Muscular/genética , Atrofia Muscular/patologia , Osteoartrite do Quadril/patologia
12.
Dermatol Ther ; 33(6): e13812, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32526051

RESUMO

We report the case of a positive COVID-19 patient who presented to our hospital for a maculopapular skin rash which appeared 7 days after the onset of COVID-19 symptoms. He was 34 years old and nothing relevant was recorded at his previous anamnesis. The patient was hospitalized for 3 days and received systemic therapy with steroid, antihistamines, tocilizumab, and hydroxicloroquine. On the third day of the hospitalization the cutaneous rash had almost completely disappeared.


Assuntos
COVID-19/complicações , Dermatopatias Virais/diagnóstico , Adulto , Anticorpos Monoclonais Humanizados/administração & dosagem , COVID-19/diagnóstico , Antagonistas dos Receptores Histamínicos/administração & dosagem , Hospitalização , Humanos , Hidroxicloroquina/administração & dosagem , Masculino , Dermatopatias Virais/tratamento farmacológico , Dermatopatias Virais/patologia , Esteroides/administração & dosagem
13.
Clin Endocrinol (Oxf) ; 90(1): 241-249, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30358903

RESUMO

OBJECTIVE: Patients with chronic kidney disease (CKD) have dysregulated cortisol metabolism secondary to changes in 11ß-hydroxysteroid dehydrogenase (11ß-HSD) enzymes. The determinants of this and its clinical implications are poorly defined. METHODS: We performed a cross-sectional study to characterize shifts in cortisol metabolism in relation to renal function, inflammation and glycaemic control. Systemic activation of cortisol by 11ß-HSD was measured as the metabolite ratio (tetrahydrocortisol [THF]+5α-tetrahydrocortisol [5αTHF])/tetrahydrocortisone (THE) in urine. RESULTS: The cohort included 342 participants with a median age of 63 years, median estimated glomerular filtration rate (eGFR) of 28 mL/min/1.73 m2 and median urine albumin-creatinine ratio of 35.5 mg/mmol. (THF+5αTHF)/THE correlated negatively with eGFR (Spearman's ρ = -0.116, P = 0.032) and positively with C-reactive protein (ρ = 0.208, P < 0.001). In multivariable analysis, C-reactive protein remained a significant independent predictor of (THF+5αTHF)/THE, but eGFR did not. Elevated (THF+5αTHF)/THE was associated with HbA1c (ρ = 0.144, P = 0.008) and diabetes mellitus (odds ratio for high vs low tertile of (THF+5αTHF)/THE 2.57, 95% confidence interval 1.47-4.47). Associations with diabetes mellitus and with HbA1c among the diabetic subgroup were independent of eGFR, C-reactive protein, age, sex and ethnicity. CONCLUSIONS: In summary, glucocorticoid activation by 11ß-HSD in our cohort comprising a spectrum of renal function was associated with inflammation and impaired glucose control.


Assuntos
Glicemia/metabolismo , Glucocorticoides/metabolismo , Inflamação/etiologia , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/enzimologia , 11-beta-Hidroxiesteroide Desidrogenases/metabolismo , Idoso , Proteína C-Reativa/metabolismo , Estudos Transversais , Diabetes Mellitus , Feminino , Taxa de Filtração Glomerular , Hemoglobinas Glicadas/análise , Humanos , Hidrocortisona/metabolismo , Masculino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/patologia
14.
Phys Rev Lett ; 123(4): 045501, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31491265

RESUMO

Understanding the local atomic order in amorphous thin film coatings and how it relates to macroscopic performance factors, such as mechanical loss, provides an important path towards enabling the accelerated discovery and development of improved coatings. High precision x-ray scattering measurements of thin films of amorphous zirconia-doped tantala (ZrO_{2}-Ta_{2}O_{5}) show systematic changes in intermediate range order (IRO) as a function of postdeposition heat treatment (annealing). Atomic modeling captures and explains these changes, and shows that the material has building blocks of metal-centered polyhedra and the effect of annealing is to alter the connections between the polyhedra. The observed changes in IRO are associated with a shift in the ratio of corner-sharing to edge-sharing polyhedra. These changes correlate with changes in mechanical loss upon annealing, and suggest that the mechanical loss can be reduced by developing a material with a designed ratio of corner-sharing to edge-sharing polyhedra.

15.
Int J Mol Sci ; 20(22)2019 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-31744114

RESUMO

Due to their potent immunomodulatory anti-inflammatory properties, synthetic glucocorticoids (GCs) are widely utilized in the treatment of chronic inflammatory disease. In this review, we examine our current understanding of how chronic inflammation and commonly used therapeutic GCs interact to regulate bone and muscle metabolism. Whilst both inflammation and therapeutic GCs directly promote systemic osteoporosis and muscle wasting, the mechanisms whereby they achieve this are distinct. Importantly, their interactions in vivo are greatly complicated secondary to the directly opposing actions of GCs on a wide array of pro-inflammatory signalling pathways that underpin catabolic and anti-anabolic metabolism. Several clinical studies have attempted to address the net effects of therapeutic glucocorticoids on inflammatory bone loss and muscle wasting using a range of approaches. These have yielded a wide array of results further complicated by the nature of inflammatory disease, underlying the disease management and regimen of GC therapy. Here, we report the latest findings related to these pathway interactions and explore the latest insights from murine models of disease aimed at modelling these processes and delineating the contribution of pre-receptor steroid metabolism. Understanding these processes remains paramount in the effective management of patients with chronic inflammatory disease.


Assuntos
Osso e Ossos/efeitos dos fármacos , Glucocorticoides/farmacologia , Inflamação/tratamento farmacológico , Músculo Esquelético/efeitos dos fármacos , Animais , Osso e Ossos/metabolismo , Glucocorticoides/uso terapêutico , Humanos , Inflamação/metabolismo , Inflamação/patologia , Músculo Esquelético/metabolismo , Osteoporose/tratamento farmacológico , Osteoporose/metabolismo , Osteoporose/patologia , Receptores de Glucocorticoides/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo
16.
Phys Rev Lett ; 120(26): 263602, 2018 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-30004721

RESUMO

Thermal noise of highly reflective mirror coatings is a major limit to the sensitivity of many precision laser experiments with strict requirements such as low optical absorption. Here, we investigate amorphous silicon and silicon nitride as an alternative to the currently used combination of coating materials, silica, and tantala. We demonstrate an improvement by a factor of ≈55 with respect to the lowest so far reported optical absorption of amorphous silicon at near-infrared wavelengths. This reduction was achieved via a combination of heat treatment, final operation at low temperature, and a wavelength of 2 µm instead of the more commonly used 1550 nm. Our silicon-based coating offers a factor of 12 thermal noise reduction compared to the performance possible with silica and tantala at 20 K. In gravitational-wave detectors, a noise reduction by a factor of 12 corresponds to an increase in the average detection rate by three orders of magnitude (≈12^{3}).

17.
Phys Rev Lett ; 121(19): 191101, 2018 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-30468587

RESUMO

Amorphous silicon has ideal properties for many applications in fundamental research and industry. However, the optical absorption is often unacceptably high, particularly for gravitational-wave detection. We report a novel ion-beam deposition method for fabricating amorphous silicon with unprecedentedly low unpaired electron-spin density and optical absorption, the spin limit on absorption being surpassed for the first time. At low unpaired electron density, the absorption is no longer correlated with electron spins, but with the electronic mobility gap. Compared to standard ion-beam deposition, the absorption at 1550 nm is lower by a factor of ≈100. This breakthrough shows that amorphous silicon could be exploited as an extreme performance optical coating in near-infrared applications, and it represents an important proof of concept for future gravitational-wave detectors.

18.
Opt Express ; 25(4): 3196-3213, 2017 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-28241536

RESUMO

Hydroxide-catalysis bonding is a high precision jointing technique producing strong, transparent and thin bonds, the use of which in the delicate fused silica mirror suspensions of aLIGO have been instrumental in the first detections of gravitational radiation. More sensitive future gravitational wave detectors will require more accurate (ideally in situ) measurements of properties such as bond thickness. Here a non-destructive technique is presented in which the thickness and refractive index of a bond are determined from measurements of optical reflectivity. The reflectivity of a bond made between two fused silica discs using sodium silicate solution is less than 1⋅10-3 after 3 months. The thickness decreases to a constant value of around 140 nm at its minimum and the refractive index increases from 1.36 to 1.45. This proves that as well as determination of bond thickness in situ this bonding technique is highly interesting for optical applications.

19.
J Pathol ; 240(4): 472-483, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27578244

RESUMO

Muscle wasting is a common feature of inflammatory myopathies. Glucocorticoids (GCs), although effective at suppressing inflammation and inflammatory muscle loss, also cause myopathy with prolonged administration. 11ß-Hydroxysteroid dehydrogenase type 1 (11ß-HSD1) is a bidirectional GC-activating enzyme that is potently upregulated by inflammation within mesenchymal-derived tissues. We assessed the regulation of this enzyme with inflammation in muscle, and examined its functional impact on muscle. The expression of 11ß-HSD1 in response to proinflammatory stimuli was determined in a transgenic murine model of chronic inflammation (TNF-Tg) driven by overexpression of tumour necrosis factor (TNF)-α within tissues, including muscle. The inflammatory regulation and functional consequences of 11ß-HSD1 expression were examined in primary cultures of human and murine myotubes and human and murine muscle biopsies ex vivo. The contributions of 11ß-HSD1 to muscle inflammation and wasting were assessed in vivo with the TNF-Tg mouse on an 11ß-HSD1 null background. 11ß-HSD1 was significantly upregulated within the tibialis anterior and quadriceps muscles from TNF-Tg mice. In human and murine primary myotubes, 11ß-HSD1 expression and activity were significantly increased in response to the proinflammatory cytokine TNF-α (mRNA, 7.6-fold, p < 0.005; activity, 4.1-fold, p < 0.005). Physiologically relevant levels of endogenous GCs activated by 11ß-HSD1 suppressed proinflammatory cytokine output (interkeukin-6, TNF-α, and interferon-γ), but had little impact on markers of muscle wasting in human myotube cultures. TNF-Tg mice on an 11ß-11ß-HSD1 knockout background developed greater muscle wasting than their TNF-Tg counterparts (27.4% less; p < 0.005), with smaller compacted muscle fibres and increased proinflammatory gene expression relative to TNF-Tg mice with normal 11ß-HSD1 activity. This study demonstrates that inflammatory stimuli upregulate 11ß-HSD1 expression and GC activation within muscle. Although concerns have been raised that excess levels of GCs may be detrimental to muscle, in this inflammatory TNF-α-driven model, local endogenous GC activation appears to be an important anti-inflammatory response that protects against inflammatory muscle wasting in vivo. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.


Assuntos
11-beta-Hidroxiesteroide Desidrogenase Tipo 1/fisiologia , Miosite/complicações , Sarcopenia/etiologia , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/biossíntese , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/deficiência , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/genética , Idoso , Animais , Biópsia , Células Cultivadas , Doença Crônica , Citocinas/biossíntese , Modelos Animais de Doenças , Regulação Enzimológica da Expressão Gênica , Glucocorticoides/fisiologia , Humanos , Hidrocortisona/biossíntese , Camundongos Transgênicos , Pessoa de Meia-Idade , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Miosite/enzimologia , Miosite/patologia , Sarcopenia/enzimologia , Sarcopenia/patologia , Sarcopenia/prevenção & controle , Especificidade da Espécie , Fator de Necrose Tumoral alfa/genética , Regulação para Cima/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA