Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 52
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
2.
Can J Neurol Sci ; 50(5): 703-709, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-36017730

RESUMO

OBJECTIVE: To characterize Parkinson's disease (PD) symptoms based on the presence, onset time, and severity of rapid eye movement sleep behavior disorder (RBD) and their association with impulse control disorders (ICD). BACKGROUND: RBD is a frequent non-motor symptom in PD, usually described as prodromal. The severity of RBD according to the start time and its relationship with ICD in PD needs further clarification. METHODS: A survey-based study was performed to determine the presence of RBD symptoms, their severity, and the temporal relationship with the PD onset. The survey included RBD1Q, the Mayo Sleep, and the RBDQ-HK questionnaires and questions about clinical characteristics, including ICD. Only PD patients with care partners spending night hours in the same room were included. RESULTS: 410 PD patients were included: 206 with RBD (50.2%) and 204 non-RBD (49.8%). The PD-RBD patients were younger and their daily levodopa dose was higher than the non-RBD group. Most of these patients developed RBD symptoms after the onset of clinical PD were younger at motor symptom onset and had higher scores in the hallucinations and psychosis subsection of MDS-UPDRS-I. RBD group had a more severe non-motor phenotype, including more ICD than those without RBD, mainly due to higher compulsive eating. CONCLUSIONS: In our study, most patients recognized RBD symptoms after the onset of the PD motor symptoms and the clinical features of PD with and without RBD were distinctive, supporting the hypothesis that PD-RBD might represent a variant pattern of neurodegeneration.


Assuntos
Doença de Parkinson , Transtorno do Comportamento do Sono REM , Humanos , Doença de Parkinson/complicações , Doença de Parkinson/epidemiologia , Transtorno do Comportamento do Sono REM/etiologia , Transtorno do Comportamento do Sono REM/complicações , Levodopa , Sono , Inquéritos e Questionários
3.
Artigo em Inglês | MEDLINE | ID: mdl-35633037

RESUMO

OBJECTIVES: Caregiving burdens are a substantial concern in the clinical care of persons with neurodegenerative disorders. In the Ontario Neurodegenerative Disease Research Initiative, we used the Zarit's Burden Interview (ZBI) to examine: (1) the types of burdens captured by the ZBI in a cross-disorder sample of neurodegenerative conditions (2) whether there are categorical or disorder-specific effects on caregiving burdens, and (3) which demographic, clinical, and cognitive measures are related to burden(s) in neurodegenerative disorders? METHODS/DESIGN: N = 504 participants and their study partners (e.g., family, friends) across: Alzheimer's disease/mild cognitive impairment (AD/MCI; n = 120), Parkinson's disease (PD; n = 136), amyotrophic lateral sclerosis (ALS; n = 38), frontotemporal dementia (FTD; n = 53), and cerebrovascular disease (CVD; n = 157). Study partners provided information about themselves, and information about the clinical participants (e.g., activities of daily living (ADL)). We used Correspondence Analysis to identify types of caregiving concerns in the ZBI. We then identified relationships between those concerns and demographic and clinical measures, and a cognitive battery. RESULTS: We found three components in the ZBI. The first was "overall burden" and was (1) strongly related to increased neuropsychiatric symptoms (NPI severity r = 0.586, NPI distress r = 0.587) and decreased independence in ADL (instrumental ADLs r = -0.566, basic ADLs r = -0.43), (2) moderately related to cognition (MoCA r = -0.268), and (3) showed little-to-no differences between disorders. The second and third components together showed four types of caregiving concerns: current care of the person with the neurodegenerative disease, future care of the person with the neurodegenerative disease, personal concerns of study partners, and social concerns of study partners. CONCLUSIONS: Our results suggest that the experience of caregiving in neurodegenerative and cerebrovascular diseases is individualized and is not defined by diagnostic categories. Our findings highlight the importance of targeting ADL and neuropsychiatric symptoms with caregiver-personalized solutions.


Assuntos
Transtornos Cerebrovasculares , Demência Frontotemporal , Doenças Neurodegenerativas , Atividades Cotidianas , Cuidadores/psicologia , Humanos , Ontário
4.
J Foot Ankle Surg ; 60(5): 891-896, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33785240

RESUMO

Numerous techniques have been described for first metatarsophalangeal joint (MTPJ) fusion. The aim of this study was to prospectively evaluate an innovative plating system which uses a cross plate compression screw. Thirty consecutive first MTPJ fusions in 28 patients were evaluated. All procedures were performed by a single fellowship trained consultant foot and ankle surgeon. Patient function was evaluated preoperatively at 6 and at 12 months using the Manchester-Oxford Foot Questionnaire (MOXFQ). Union rates and complications were recorded. Postoperative MOXFQ scores demonstrated significant improvement in all domains, with mean improvement at 12 months of 35, 27, 17 and 106 points for pain, walking/standing, social interactions and combined scores respectively (p value ≤.0001). In all 30 cases, clinical and radiological evidence of union was achieved by 6 months. Superficial infection occurred in 1 (3%) case. One (3%) case required plate removal due to soft tissue irritation. There were no plate failures. This evaluation study demonstrates that this cross-plate compression plating system is safe, provides high patient satisfaction and reliable union, with low complication rates. Prospective comparative research is now required to determine the optimal technique for first MTPJ fusion.


Assuntos
Hallux Rigidus , Articulação Metatarsofalângica , Artrodese , Placas Ósseas , Parafusos Ósseos , Hallux Rigidus/diagnóstico por imagem , Hallux Rigidus/cirurgia , Humanos , Articulação Metatarsofalângica/diagnóstico por imagem , Articulação Metatarsofalângica/cirurgia , Estudos Retrospectivos , Resultado do Tratamento
5.
Molecules ; 25(21)2020 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-33138276

RESUMO

This study explores the use of a novel activating agent and demonstrates the production and characterisation of activated carbon (AC) from a combine palm waste (CPW) in 3:2:1 proportion by weight of empty fruit bunch, mesocarp fibre and palm kernel shell. The resulting biomass was processed by a microwave-assisted method using trona and compared with material produced by conventional routes. These results demonstrate the potential of trona ore as an activating agent and the effectiveness of using a combined palm waste for a single stream activation process. It also assesses the effectiveness of trona ore in the elimination of alcohol, acids and aldehydes; with a focus on increasing the hydrophilicity of the resultant AC. The optimum results for the conventional production technique at 800 °C yielded a material with SBET 920 m2/g, Vtotal 0.840 cm3/g, a mean pore diameter of 2.2 nm and an AC yield 40%. The optimum outcome of the microwave assisted technique for CPW was achieved at 600 W, SBET is 980 m2/g; Vtotal 0.865 cm3/g; a mean pore diameter 2.2 nm and an AC yield of 42%. Fourier transform infrared spectrometry analyses showed that palm waste can be combined to produce AC and that trona ore has the capacity to significantly enhance biomass activation.


Assuntos
Bicarbonatos/química , Biomassa , Carvão Vegetal/química , Micro-Ondas , Poaceae/química
6.
Energy Convers Manag ; 163: 74-85, 2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29725147

RESUMO

A probabilistic modelling approach was developed and applied to investigate the energy and environmental performance of an innovative sanitation system, the "Nano-membrane Toilet" (NMT). The system treats human excreta via an advanced energy and water recovery island with the aim of addressing current and future sanitation demands. Due to the complex design and inherent characteristics of the system's input material, there are a number of stochastic variables which may significantly affect the system's performance. The non-intrusive probabilistic approach adopted in this study combines a finite number of deterministic thermodynamic process simulations with an artificial neural network (ANN) approximation model and Monte Carlo simulations (MCS) to assess the effect of system uncertainties on the predicted performance of the NMT system. The joint probability distributions of the process performance indicators suggest a Stirling Engine (SE) power output in the range of 61.5-73 W with a high confidence interval (CI) of 95%. In addition, there is high probability (with 95% CI) that the NMT system can achieve positive net power output between 15.8 and 35 W. A sensitivity study reveals the system power performance is mostly affected by SE heater temperature. Investigation into the environmental performance of the NMT design, including water recovery and CO2/NOx emissions, suggests significant environmental benefits compared to conventional systems. Results of the probabilistic analysis can better inform future improvements on the system design and operational strategy and this probabilistic assessment framework can also be applied to similar complex engineering systems.

7.
Faraday Discuss ; 192: 97-111, 2016 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-27485382

RESUMO

Four types of synthetic sorbents were developed for high-temperature post-combustion calcium looping CO2 capture using Longcal limestone. Pellets were prepared with: lime and cement (LC); lime and flour (LF); lime, cement and flour (LCF); and lime, cement and flour doped with seawater (LCFSW). Flour was used as a templating material. All samples underwent 20 cycles in a TGA under two different calcination conditions. Moreover, the prepared sorbents were tested for 10 carbonation/calcination cycles in a 68 mm-internal-diameter bubbling fluidized bed (BFB) in three environments: with no sulphur and no steam; in the presence of sulphur; and with steam. When compared to limestone, all the synthetic sorbents exhibited enhanced CO2 capture performance in the BFB experiments, with the exception of the sample doped with seawater. In the BFB tests, the addition of cement binder during the pelletisation process resulted in the increase of CO2 capture capacity from 0.08 g CO2 per g sorbent (LF) to 0.15 g CO2 per g sorbent (LCF) by the 10th cycle. The CO2 uptake in the presence of SO2 dramatically declined by the 10th cycle; for example, from 0.22 g CO2 per g sorbent to 0.05 g CO2 per g sorbent in the case of the untemplated material (LC). However, as expected all samples showed improved performance in the presence of steam, and the decay of reactivity during the cycles was less pronounced. Nevertheless, in the BFB environment, the templated pellets showed poorer CO2 capture performance. This is presumably because of material loss due to attrition under the FB conditions. By contrast, the templated materials performed better than untemplated materials under TGA conditions. This indicates that the reduction of attrition is critical when employing templated materials in realistic systems with FB reactors.

8.
Environ Sci Technol ; 48(9): 5322-8, 2014 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-24678727

RESUMO

In this work, we report the development of a synthetic CO2 sorbent that possesses a high cyclic CO2 uptake capacity and, in addition, sufficient mechanical strength to allow it to be used in fluidized-bed reactors. To overcome the problem of elutriation of the original powdered material, the synthetic CO2 sorbent was pelletized. An important aspect of this work was to assess the effect of steam on the cyclic CO2 capture capacity of the original, powdered CO2 sorbent and the pelletized material. After 30 cycles of repeated calcination and carbonation reactions conducted in a fluidized bed, the CO2 uptake of the pellets was 0.29 g of CO2/g of sorbent, a value that is 45% higher than that measured for the reference limestone. For the case that carbonation/calcination cycles were conducted in a thermogravimetric analyzer under steam-free carbonation conditions, the CO2 uptake of the best sorbent was 0.33 g of CO2/g of sorbent (after 10 cycles). Importantly, it should be noted that, after 10 cycles using wet carbonation conditions, the CO2 uptake of this material increased by 55% when compared to dry conditions. This observation was attributed to enhanced solid-state diffusion in the CaCO3 product layer under wet conditions. However, independent of the reaction conditions, the pelletized material showed a lower cyclic CO2 uptake when compared to the original powder. A detailed morphological characterization of the pellets indicated that the destruction of the primary, hollow micrometer-sized spheres during pelletization was responsible for the lower cyclic CO2 uptake of the pellets.


Assuntos
Compostos de Cálcio/química , Dióxido de Carbono/química , Carbono/química , Óxidos/química , Vapor , Carbonato de Cálcio/química , Microscopia Eletrônica de Varredura , Pós , Termogravimetria
9.
Sci Rep ; 14(1): 1962, 2024 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-38263453

RESUMO

Footprints represent a relevant vestige providing direct information on the biology, locomotion, and behaviour of the individuals who left them. However, the spatiotemporal distribution of hominin footprints is heterogeneous, particularly in North Africa, where no footprint sites were known before the Holocene. This region is important in the evolution of hominins. It notably includes the earliest currently known Homo sapiens (Jebel Irhoud) and the oldest and richest African Middle Stone Age hominin sites. In this fragmented ichnological record, we report the discovery of 85 human footprints on a Late Pleistocene now indurated beach surface of about 2800 m2 at Larache (Northwest coast of Morocco). The wide range of sizes of the footprints suggests that several individuals from different age groups made the tracks while moving landward and seaward across a semi-dissipative bar-trough sandy beach foreshore. A geological investigation and an optically stimulated luminescence dating of a rock sample extracted from the tracksite places this hominin footprint surface at 90.3 ± 7.6 ka (MIS 5, Late Pleistocene). The Larache footprints are, therefore, the oldest attributed to Homo sapiens in Northern Africa and the Southern Mediterranean.


Assuntos
Hominidae , Animais , Humanos , África do Norte , Marrocos
10.
Environ Sci Technol ; 47(11): 6007-14, 2013 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-23675760

RESUMO

Sorbent-enhanced steam methane reforming (SE-SMR) is an emerging technology for the production of high-purity hydrogen from hydrocarbons with in situ CO2 capture. Here, SE-SMR was studied using a mixture containing a Ni-hydrotalcite-derived catalyst and a synthetic, Ca-based, calcium aluminate supported CO2 sorbent. The fresh and cycled materials were characterized using N2 physisorption, X-ray diffraction, and scanning and transmission electron microscopy. The combination of a Ni-hydrotalcite catalyst and the synthetic CO2 sorbent produced a stream of high-purity hydrogen, that is, 99 vol % (H2O- and N2-free basis). The CaO conversion of the synthetic CO2 sorbent was 0.58 mol CO2/mol CaO after 10 cycles, which was more than double the value achieved by limestone. The favorable CO2 capture characteristics of the synthetic CO2 sorbent were attributed to the uniform dispersion of CaO on a stable nanosized mayenite framework, thus retarding thermal sintering of the material. On the other hand, the cycled limestone lost its nanostructured morphology completely over 10 SE-SMR cycles due to its intrinsic lack of a support component.


Assuntos
Hidrogênio/química , Metano/química , Compostos de Alumínio/química , Compostos de Cálcio/química , Dióxido de Carbono/química , Catálise , Microscopia Eletrônica de Transmissão , Níquel , Vapor , Difração de Raios X
11.
Sci Total Environ ; 857(Pt 1): 159155, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36206897

RESUMO

Over the years, the transformation of biomass into a plethora of renewable value-added products has been identified as a promising strategy to fulfil high energy demands, lower greenhouse gas emissions, and exploit under-utilized resources. Techno-economic analysis (TEA) and life-cycle assessment (LCA) are essential to scale up this process while lowering the conversion cost. In this study, trade-offs are made between economic, environmental, and technical indicators produced from these methodologies to better evaluate the commercialization potential of biomass pyrolysis. This research emphasizes the necessity of combining LCA and TEA variables to assess the performance of the early-stage technology and associated constraints. The important findings based on the LCA analysis imply that most of the studies reported in literature focussed on the global warming potentials (GWP) under environmental category by considering greenhouse gases (GHGs) as evaluation parameter, neglecting many other important environmental indices. In addition, the upstream and downstream processes play an important role in understanding the life cycle impacts of a biomass based biorefinery. Under upstream conditions, the use of a specific type of feedstock may influence the LCA conclusions and technical priority. Under downstream conditions, the product utilization as fuels in different energy backgrounds is crucial to the overall impact potentials of the pyrolysis systems. In view of the TEA analysis, investigations towards maximizing the yield of valuable co-products would play an important role in the commercialization of pyrolysis process. However, comprehensive research to compare the conventional, advanced, and emerging approaches of biomass pyrolysis from the economic perspective is currently not available in the literature.


Assuntos
Biocombustíveis , Pirólise , Biomassa
12.
Pain ; 164(5): 1051-1066, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-36448978

RESUMO

ABSTRACT: The nucleus of the solitary tract (NTS) contains pro-opiomelanocortin (POMC) neurons that are 1 of the 2 major sources of ß-endorphin in the brain. The functional role of these NTS POMC neurons in nociceptive and cardiorespiratory function is debated. We have shown that NTS POMC optogenetic activation produces bradycardia and transient apnoea in a working heart-brainstem preparation and chemogenetic activation with an engineered ion channel (PSAM) produced opioidergic analgesia in vivo. To better define the role of the NTS POMC neurons in behaving animals, we adopted in vivo optogenetics (ChrimsonR) and excitatory/inhibitory chemogenetic DREADD (hM3Dq/hM4Di) strategies in POMC-Cre mice. We show that optogenetic activation of NTS POMC neurons produces time-locked, graded, transient bradycardia and bradypnoea in anaesthetised mice that is naloxone sensitive (1 mg/kg, i.p.), suggesting a role of ß-endorphin. Both optogenetic and chemogenetic activation of NTS POMC neurons produces sustained thermal analgesia in behaving mice that can be blocked by naloxone. It also produced analgesia in an inflammatory pain model (carrageenan) but not in a neuropathic pain model (tibial nerve transection). Inhibiting NTS POMC neurons does not produce any effect on basal nociception but inhibits stress-induced analgesia (unlike inhibition of arcuate POMC neurons). Activation of NTS POMC neuronal populations in conscious mice did not cause respiratory depression, anxiety, or locomotor deficit (in open field) or affective preference. These findings indicate that NTS POMC neurons play a key role in the generation of endorphinergic endogenous analgesia and can also regulate cardiorespiratory function.


Assuntos
Analgesia , Pró-Opiomelanocortina , Camundongos , Animais , Pró-Opiomelanocortina/genética , Pró-Opiomelanocortina/metabolismo , Pró-Opiomelanocortina/farmacologia , Núcleo Solitário , Bradicardia , beta-Endorfina , Neurônios , Naloxona/farmacologia , Dor
13.
Environ Sci Technol ; 46(22): 12720-5, 2012 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-23088430

RESUMO

This paper presents a novel method for reactivation of spent CaO-based sorbents from calcium looping (CaL) cycles for CO(2) capture. A spent Cadomin limestone-derived sorbent sample from a pilot-scale fluidized bed (FBC) CaL reactor is used for reactivation. The calcined sorbent is sprayed by water in a pelletization vessel. This reactivation method produces pellets ready to be used in FBC reactors. Moreover, this procedure enables the addition of calcium aluminate cement to further enhance sorbent strength. The characterization of reactivated material by nitrogen physisorption (BET, BJH) and scanning electron microscopy (SEM) confirmed the enhanced morphology of sorbent particles for reaction with CO(2). This improved CO(2) carrying capacity was demonstrated in calcination/carbonation tests performed in a thermogravimetric analyzer (TGA). Finally, the resulting pellets displayed a high resistance to attrition during fluidization in a bubbling bed.


Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Materiais de Construção/análise , Recuperação e Remediação Ambiental/métodos , Óxidos/química , Água/química , Adsorção , Carbonato de Cálcio/química , Dióxido de Carbono/química , Temperatura Alta , Microscopia Eletrônica de Varredura , Termogravimetria
14.
Environ Sci Technol ; 46(2): 1262-9, 2012 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-22191682

RESUMO

Calcium looping is a high-temperature CO(2) capture technology applicable to the postcombustion capture of CO(2) from power station flue gas, or integrated with fuel conversion in precombustion CO(2) capture schemes. The capture technology uses solid CaO sorbent derived from natural limestone and takes advantage of the reversible reaction between CaO and CO(2) to form CaCO(3); that is, to achieve the separation of CO(2) from flue or fuel gas, and produce a pure stream of CO(2) suitable for geological storage. An important characteristic of the sorbent, affecting the cost-efficiency of this technology, is the decay in reactivity of the sorbent over multiple CO(2) capture-and-release cycles. This work reports on the influence of high-temperature steam, which will be present in flue (about 5-10%) and fuel (∼20%) gases, on the reactivity of CaO sorbent derived from four natural limestones. A significant increase in the reactivity of these sorbents was found for 30 cycles in the presence of steam (from 1-20%). Steam influences the sorbent reactivity in two ways. Steam present during calcination promotes sintering that produces a sorbent morphology with most of the pore volume associated with larger pores of ∼50 nm in diameter, and which appears to be relatively more stable than the pore structure that evolves when no steam is present. The presence of steam during carbonation reduces the diffusion resistance during carbonation. We observed a synergistic effect, i.e., the highest reactivity was observed when steam was present for both calcination and carbonation.


Assuntos
Poluentes Atmosféricos/química , Compostos de Cálcio/química , Dióxido de Carbono/química , Óxidos/química , Vapor/análise , Adsorção , Poluição do Ar/prevenção & controle , Temperatura Alta , Reprodutibilidade dos Testes
15.
Bioresour Technol ; 364: 128087, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36216287

RESUMO

Biomass pyrolysis has recently gained increasing attention as a thermochemical conversion process for obtaining value-added products, thanks to the development of cutting-edge, innovative and cost-effective pyrolysis processes. Over time, new and novel pyrolysis techniques have emerged, and these processes can be tuned to maximize the production of high-quality hydrogen. This review examines recent advancements in biomass pyrolysis by classifying them into conventional, advanced and emerging approaches. A comprehensive overview on the recent advancements in biomass pyrolysis, highlighting the current status for industrial applications is presented. Further, the impact of each technique under different approaches on conversion of biomass for hydrogen production is evaluated. Techniques, such as inline catalytic pyrolysis, microwave pyrolysis, etc., can be employed for the sustainable production of hydrogen. Finally, the techno-economic analysis is presented to understand the viability of pyrolysis at large scale. The outlook highlights discernments into future directions, aimed to overcome the current shortcomings.

16.
Arch Dis Child ; 107(8): 747-751, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35172964

RESUMO

OBJECTIVE: European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) guidelines on coeliac disease (CD) recommend that children who have IgA-based antitissue transglutaminase (TGA-IgA) titre ≥10× upper limit of normal (ULN) and positive antiendomysial antibody, can be reliably diagnosed with CD via the no-biopsy pathway. The aim of this study was to examine the relationship between TGA-IgA ≥5×ULN and histologically confirmed diagnosis of CD. METHODS: Data including TGA-IgA levels at upper gastrointestinal endoscopy and histological findings from children diagnosed with CD following endoscopy from 2006 to 2021 were analysed. CD was confirmed by Marsh-Oberhuber histological grading 2 to 3 c. Statistical analysis was performed using χ² analysis (p<0.05= significant). RESULTS: 722 of 758 children had histological confirmation of CD. 457 children had TGA-IgA ≥5×ULN and 455 (99.5%) of these had histological confirmation for CD; the two that did not had eventual diagnosis of CD based on clinicopathological features. 114 of 457 had between TGA-IgA ≥5×ULN and <10×ULN, all had confirmed CD. The likelihood of a positive biopsy with TGA-IgA ≥5×ULN (455/457) compared with TGA-IgA <5×ULN (267/301) has strong statistical significance (p<0.00001). The optimal TGA-IgA cut-off from receiver operating characteristic curve analysis was determined to be below 5×ULN for the two assays used. CONCLUSION: 99.5% of children with TGA-IgA ≥5×ULN had histological confirmation of CD, suggesting that CD diagnosis can be made securely in children with TGA-IgA ≥5×ULN. If other studies confirm this finding, there is a case to be made to modify the ESPGHAN guidelines to a lower threshold of TGA-IgA for serological diagnosis of CD.


Assuntos
Doença Celíaca , Transglutaminases , Autoanticorpos , Biópsia , Doença Celíaca/diagnóstico , Criança , Humanos , Imunoglobulina A , Transglutaminases/sangue
17.
Blood Cells Mol Dis ; 47(3): 176-81, 2011 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-21839656

RESUMO

Studies of hemolytic agents on G6PD-deficient subjects have been extensively performed on red blood cells obtained from donors, only using in vitro methods. However, there has been no adequate G6PD-deficient animal model for in vivo assessment of potentially hemolytic agents. The objective of this study is to establish a novel mouse model of severe G6PD-deficiency, with high susceptibility to hemolytic damage upon oxidative agents. To create this model, G6PD mutant Gpdx allele was introduced into the C57L/J mouse strain background by breeding program. The hemolytic toxicity of naphthalene and its metabolite α-naphthol on G6PD-deficient red blood cells was evaluated. Our data showed that the F2 homozygous Gpdx mutant with C57L/J background exhibiting the G6PD activity was 0.9±0.1 U/g Hb, level similar to those of G6PD deficiency in human. A significantly negative correlation was demonstrated between GSH percentage reduction and G6PD activity (r=-0.51, p<0.001) upon challenge of the red blood cells with alpha-naphthol in vitro. Similar correlation was also found between GSSG elevation and G6PD activity. Our in vivo studies showed that the administration of naphthalene at 250 mg/kg inflicted significant oxidative damage to the G6PD-deficient mice, as illustrated by the decrease of the GSH-to-GSSG ratio (by 34.2%, p=0.005) and the increase of the methemoglobin level (by 1.9 fold, p<0.001). Hemolytic anemia was also found in G6PD-deficient mice at this dosage of naphthalene. In summary, this novel mouse model could be utilized as a screening platform to more accurately determine the hemolytic toxicity of pharmacological agents on G6PD-deficient subjects.


Assuntos
Modelos Animais de Doenças , Eritrócitos , Deficiência de Glucosefosfato Desidrogenase/enzimologia , Glucosefosfato Desidrogenase , Hemolíticos/farmacologia , Anemia Hemolítica/induzido quimicamente , Animais , Cruzamento/métodos , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Feminino , Glucosefosfato Desidrogenase/genética , Glucosefosfato Desidrogenase/metabolismo , Deficiência de Glucosefosfato Desidrogenase/metabolismo , Glutationa/metabolismo , Dissulfeto de Glutationa/metabolismo , Humanos , Masculino , Metemoglobina/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Mutação , Naftalenos/farmacologia , Naftóis/farmacologia , Estresse Oxidativo
18.
Environ Sci Technol ; 45(24): 10750-6, 2011 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-22022778

RESUMO

Calcium looping cycles (CaL) and chemical looping combustion (CLC) are two new, developing technologies for reduction of CO(2) emissions from plants using fossil fuels for energy production, which are being intensively examined. Calcium looping is a two-stage process, which includes oxy-fuel combustion for sorbent regeneration, i.e., generation of a concentrated CO(2) stream. This paper discuss the development of composite materials which can use copper(II)-oxide (CuO) as an oxygen carrier to provide oxygen for the sorbent regeneration stage of calcium looping. In other words, the work presented here involves integration of calcium looping and chemical looping into a new class of postcombustion CO(2) capture processes designated as integrated CaL and CLC (CaL-CLC or Ca-Cu looping cycles) using composite pellets containing lime (CaO) and CuO together with the addition of calcium aluminate cement as a binder. Their activity was tested in a thermogravimetric analyzer (TGA) during calcination/reduction/oxidation/carbonation cycles. The calcination/reduction typically was performed in methane (CH(4)), and the oxidation/carbonation stage was carried out using a gas mixture containing both CO(2) and O(2). It was confirmed that the material synthesized is suitable for the proposed cycles; with the very favorable finding that reduction/oxidation of the oxygen carrier is complete. Various schemes for the Ca-Cu looping process have been explored here that would be compatible with these new composite materials, along with some different possibilities for flow directions among carbonator, calciner, and air reactor.


Assuntos
Poluentes Atmosféricos/análise , Compostos de Cálcio/química , Cálcio/química , Cobre/química , Óxidos/química , Poluentes Atmosféricos/química , Poluição do Ar/prevenção & controle , Dióxido de Carbono/análise , Dióxido de Carbono/química , Manufaturas
19.
Turk J Chem ; 45(2): 452-462, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34104056

RESUMO

A gas mixture representing oxy-fuel combustion conditions was employed in a thermogravimetric analyser to determine the effect of water vapor and SO2 concentration on limestone sulfation kinetics over the temperature range of 800 to 920 °C. Here, experiments used small samples of particles (4 mg), with small particle sizes (dp < 38 µm) and large gas flow rates (120 mL/min@NTP) in order to minimize mass transfer interferences. The gas mixture contained 5000 ppmv SO2, 2% O2, and the H2O content was changed from 0% to 25% with the balance CO2. When water vapor was added to the gas mixture at lower temperatures (800-870 °C), the limestone SO2 capture efficiency increased. However, as the temperature became higher, the enhancement in total conversion values decreased. As expected, Havelock limestone at higher temperatures (890 °C, 920 °C, and 950 °C) experienced indirect sulfation and reacted at a faster rate than for lower temperatures (800-870 °C) for direct sulfation over the first five minutes of reaction time. However, the total conversion of Havelock limestone for direct sulfation was generally greater than for indirect sulfation.

20.
Biochem Biophys Res Commun ; 391(3): 1522-5, 2010 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-20035718

RESUMO

BRE, also known as TNFRSF1A modulator and BRCC45, is an evolutionarily highly conserved protein. It is a death receptor-associated protein in cytoplasm and a component of BRCA1/2-containing DNA repair complex in nucleus. BRE was found to have anti-apoptotic activity. Over-expression of BRE by transfection promoted survival of cell lines against apoptotic induction; whereas depletion of the protein by siRNA resulted in the opposite. In vivo anti-apoptotic activity of BRE was demonstrated by significant attenuation of Fas-induced acute fulminant hepatitis in transgenic mice expressing the human protein specifically in the liver. BRE was also implicated in tumor promotion by the accelerated tumor growth of Lewis Lung carcinoma transfected with human BRE; and by high expression of BRE specifically in the tumoral regions of human hepatocellular carcinoma (HCC). The present study was to test directly if transgenic expression of BRE in livers could promote HCC development in neonatal diethylnitrosamine model. By 8months after tumor induction, the maximal sizes of tumor nodules of transgenic mice were significantly larger than those of the non-transgenic controls, although the numbers of tumor nodules between the two groups did not significantly differ. Importantly, as in human HCC, the mouse endogenous BRE level was up-regulated in mouse HCC nodules. These results show that BRE over-expression can indeed promote growth, though not initiation, of liver tumors. Furthermore, the common occurrence of BRE over-expression in human and mouse HCC suggests that up-regulation of BRE is functionally important in liver tumor development.


Assuntos
Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Fígado/patologia , Proteínas do Tecido Nervoso/biossíntese , Animais , Carcinoma Hepatocelular/induzido quimicamente , Carcinoma Hepatocelular/metabolismo , Proliferação de Células , Dietilnitrosamina/toxicidade , Humanos , Fígado/metabolismo , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Hepáticas/metabolismo , Camundongos , Camundongos Transgênicos , Proteínas do Tecido Nervoso/genética , Transfecção , Regulação para Cima
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA