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1.
Nat Commun ; 11(1): 4446, 2020 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-32895387

RESUMO

Owing to the poor penetration depth of light, phototherapy, including photothermal and photodynamic therapies, remains severely ineffective in treating deep tissue infections such as methicillin-resistant Staphylococcus aureus (MRSA)-infected osteomyelitis. Here, we report a microwave-excited antibacterial nanocapturer system for treating deep tissue infections that consists of microwave-responsive Fe3O4/CNT and the chemotherapy agent gentamicin (Gent). This system, Fe3O4/CNT/Gent, is proven to efficiently target and eradicate MRSA-infected rabbit tibia osteomyelitis. Its robust antibacterial effectiveness is attributed to the precise bacteria-capturing ability and magnetic targeting of the nanocapturer, as well as the subsequent synergistic effects of precise microwaveocaloric therapy from Fe3O4/CNT and chemotherapy from the effective release of antibiotics in infection sites. The advanced target-nanocapturer of microwave-excited microwaveocaloric-chemotherapy with effective targeting developed in this study makes a major step forward in microwave therapy for deep tissue infections.


Assuntos
Nanopartículas de Magnetita/uso terapêutico , Micro-Ondas/uso terapêutico , Osteomielite/tratamento farmacológico , Infecções Estafilocócicas/tratamento farmacológico , Animais , Antibacterianos/uso terapêutico , Sistemas de Liberação de Medicamentos/métodos , Tratamento Farmacológico/métodos , Óxido Ferroso-Férrico/uso terapêutico , Gentamicinas/uso terapêutico , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Nanotubos de Carbono , Osteomielite/microbiologia , Coelhos
2.
Water Sci Technol ; 82(1): 170-184, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32910801

RESUMO

In this study, manganese dioxide was evenly distributed on the surface of activated carbon (AC), and the porous structure of AC and the surface functional groups of manganese dioxide were used to adsorb the heavy metal ion Pb(II). The advantages of microwave heating are fast heating and high selectivity. The mole ratio control of the AC and MnO2 in 1:0.1, microwave heating to 800 °C, heat preservation for 30 min. The maximum adsorption capacity of the MnO2-AC prepared by this method on Pb(II) can reach 664 mg/L at pH = 6. It can be observed by scanning electron microscope (SEM) that manganese dioxide particles are dispersed evenly on the surface and pore diameter of AC, and there is almost no agglomeration. The specific surface area was 752.8 m2/g, and the micropore area was 483.9 m2/g. The adsorption mechanism was explored through adsorption isotherm, adsorption kinetics, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS). It is speculated that the adsorption mechanism includes electrostatic interaction and specific adsorption, indicating that lead ions enter into the void of manganese dioxide and form spherical complexes. The results showed that the adsorption behavior of Pb(II) by MnO2-AC was consistent with the Langmuir adsorption model, the quasi-second-order kinetic model, and the particle internal diffusion model.


Assuntos
Compostos de Manganês , Poluentes Químicos da Água/análise , Adsorção , Carvão Vegetal , Íons , Chumbo , Micro-Ondas , Óxidos
3.
Water Sci Technol ; 82(4): 704-714, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32970623

RESUMO

The radical generation properties of hydrogen peroxide and persulfate for phenol degradation were investigated under microwave irradiation using copper-doped silicon carbide (Cu/SiC) composites as catalyst. The results showed that 90% and 70% of phenol and total organic carbon (TOC), respectively, were removed within 7 min. Microwave activation of hydrogen peroxide and sodium persulfate in terms of thermal effects and accelerated electron transfer was analyzed by degradation kinetics and X-ray photoelectron spectroscopy (XPS). The microwave activation of Na2S2O8 demonstrated that the hot spots promote decomposition of persulfate more rapidly and the rate of persulfate decomposition was more than three times the activation rate of a normal heating method. There is a synergistic effect between Cu and microwave radiation, which is highlighted by the H2O2 activation; ·OH was generated due to the redox cycle between Cu(I)/Cu(II) and was responsible for phenol degradation using H2O2. High performance liquid chromatography (HPLC) analysis indicated that hydroxylation and sulfate radicals addition of phenol were the initial oxidation reaction steps of hydrogen peroxide and persulfate, respectively, followed by further oxidation to form short-chain carboxylic acids.


Assuntos
Peróxido de Hidrogênio , Fenol , Compostos Inorgânicos de Carbono , Catálise , Micro-Ondas , Oxirredução , Compostos de Silício
4.
J Chromatogr A ; 1628: 461446, 2020 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-32822985

RESUMO

Ionic liquids, as tuneable, highly soluble, non-flammable, non-volatile and reusable extractants, have attracted extensive attention in the extraction of flavonoids from plants. In the present work, novel dual-chain imidazolium-derived ionic liquids were synthesized by a simple and efficient method and characterized (NMR spectroscopy, thermal stability, viscosity, conductivity, and polarity). Then, the imidazolium ionic liquids with different cation were used in the microwave-assisted extraction of flavonoids from Pinus massoniana Lamb. The results showed that the ionic liquid [Bmbim]Br, with a relatively low viscosity, conductivity and π* as well as a relatively large ß, offered the best extraction efficiency and selectivity for flavonoids. Subsequently, the parameters of the extraction procedure for flavonoids were optimized as follows: extraction temperature of 80 °C, extraction time of 60 min, microwave power of 300 W, solid-liquid ratio of 1:20, and [Bmbim]Br solution concentration of 1.0 mol/L. The extraction yield of total flavonoids was 41.07 mg/g. Finally, a recovery method of the ionic liquid had been demonstrated, and the recovery rate of ionic liquid was 73.14%.


Assuntos
Flavonoides/isolamento & purificação , Líquidos Iônicos/síntese química , Cátions , Flavonoides/química , Micro-Ondas , Pinus/química , Extratos Vegetais/química
5.
Chemosphere ; 260: 127681, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32758785

RESUMO

In this work, magnetic separably barium ferrite nanomaterial (BaFeO) was synthesized via citrate acid assisted sol-gel combustion method. Subsequently, X-ray diffraction (XRD), scanning electron microscopy-energy dispersion spectroscopy (SEM-EDS), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) were applied for its structural, morphological, and electromagnetic characterization. In addition, microwave (MW) absorption and thermal conversion test results indicated the BaFeO had electrothermal rather than magnetothermal conversion capacity. Meanwhile, the synthesized BaFeO showed satisfactory performance in both eliminating and mineralization of a typical triphenylmethane dye, brilliant green (BG), in MW-induced catalytic oxidation (MICO) process without extra oxidant addition. Besides, changes in element valence and content of BaFeO before and after MICO process investigated with XRD, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed its relatively stable properties. Furthermore, transition oxygen species involved in MICO process was deduced as lattice oxygen species. Then, the possible degradation pathway of BG was proposed as demethylation, open-loop of triphenylmethane, releasing one ring, formation of the benzene ring and the ultimate mineralization based on the degradation intermediates tentatively identified by gas chromatography mass spectrometry (GC/MS) and liquid chromatography mass spectrometry (LC/MS), respectively. Finally, ecotoxicity analysis by ecological structure activity relationships (ECOSAR) showed that both the acute and chronic toxicity of these intermediates were lower than that of parent BG. These findings are important regarding the development of efficient catalysts in MICO process for degradation of BG analogues in wastewater.


Assuntos
Compostos de Bário/química , Compostos Férricos/química , Nanoestruturas/química , Compostos de Amônio Quaternário/química , Catálise , Corantes/química , Magnetismo , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Micro-Ondas , Espectroscopia Fotoeletrônica , Águas Residuárias , Difração de Raios X
6.
Environ Monit Assess ; 192(8): 557, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32740832

RESUMO

Human consumption of non-steroidal anti-inflammatory drugs (NSAIDs) is increasing, which poses a great risk of pollution by these pharmaceuticals on the aquatic environment. Therefore, this study reports the optimization of microwave-assisted extraction using water as a green solvent and hollow fiber liquid-phase microextraction (HF-LPME) methods followed by high-performance liquid chromatography-high resolution mass spectrometry analysis of NSAIDs in wastewater and aquatic plant, Eichhornia crassipes. The optimized MAE resulted in efficient transfer of selected NSAIDs from plant samples into the aqueous phase yielding the recoveries ranging from 91 to115%. A multivariate approach based on half fractional factorial and central composite design was used during the optimization of HF-LPME. Under the optimized conditions, the maximum enrichment factors for naproxen, fenoprofen, diclofenac, and ibuprofen were 49, 126, 93 and 156, respectively. The overall analytical method recoveries ranged from 86 to 116% while the limits of quantitation for wastewater and plant samples ranged from 0.09 to 0.59 µg L-1 and from 0.11 to 0.59 µg kg-1, respectively. The precision of the proposed analytical method which was measured in terms of RSD values did not exceed 5%. Naproxen was the most abundant compound in both wastewater and the Eichhornia crassipes plant samples with concentrations of up to 3.30 µg L-1 and 10.97 µg kg-1, respectively. The detection of NSAIDs in Eichhornia crassipes means this plant has the ability to bioaccumulate pharmaceutical load in surface water.


Assuntos
Microextração em Fase Líquida , Micro-Ondas , Anti-Inflamatórios não Esteroides/análise , Monitoramento Ambiental , Humanos , Naproxeno/análise
7.
Water Res ; 183: 116102, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32745672

RESUMO

We report the existence and resuscitation of viable but nonculturable (VBNC) Escherichia coli O157:H7 cells in drinking water induced by the common point-of-use disinfection treatments of boiling or microwaving. Tap water and saline samples containing E. coli O157:H7 culturable cells from a bovine isolate or two clinical isolates were boiled (1, 10, or 15 min) on a hot plate or microwaved (1.5 min) to reach boiling. No culturable E. coli O157:H7 cells were observed in the treated samples using conventional plating methods. In samples boiled for 1 or 10 min, two viability assays separately detected that 2-5.5% of the cells retained an intact membrane, while 28 to 87 cells out of the initial 108 cells retained both measurable intracellular esterase activity and membrane integrity. In samples boiled for 15 min, no viable cells were detected. The microwaved samples contained 6-10% of cells with an intact membrane, while 21 to 108 cells out of the initial 108 cells retained both membrane integrity and esterase activity. The number of viable cells retaining both metabolic activity and membrane integrity were consistent in all samples, supporting the survival of a small number of E. coli O157:H7 cells in the VBNC state after boiling for 1 or 10 min or microwaving. Furthermore, the VBNC E. coli O157:H7 cells regained growth at 37 °C in culture media containing autoinducers produced by common non-pathogenic E. coli, commonly present in the human intestine, and norepinephrine. The resuscitated cells were culturable on conventional plates and expressed mRNA encoding the E. coli O157 lipopolysaccharide gene (rfbE) and the H7 flagellin gene (fliC). This study highlights potential concerns for public health risk management of VBNC E. coli O157:H7 in drinking water disinfected by heat treatment at point-of-use. The public health significance of these concerns warrants further investigation.


Assuntos
Escherichia coli O157 , Animais , Bovinos , Contagem de Células , Contagem de Colônia Microbiana , Meios de Cultura , Humanos , Micro-Ondas , Água
8.
Waste Manag ; 117: 188-197, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32861081

RESUMO

To study the effects of different ash/organics and C/H/O ratios on bio-fuel characteristics and energy efficiency, four kinds of sludge with different properties were used for microwave pyrolysis (800 °C). Moreover, the microwave pyrolysis reaction mechanisms of different sludge were also explored. The results showed that high-ash sludge could accelerate the frequency of polar molecule rotation in the microwave field due to the presence of oxides with dielectric properties in ash, thereby achieving faster heating rates and higher temperatures. However, compared with high-organic sludge, high-ash sludge exhibited lower bio-gas yield and higher bio-char yield. As the H/C ratio increased from 0.127 to 0.148, the bio-gas yield increased from 15.41% to 40.01%, and the content of H2 in bio-gas and aliphatics in bio-oil increased to 36.69 vol% and 26.54 wt%, respectively. When the O/C ratio was reduced to 1.31, the content of CO and oxygenated compound in bio-oil increased to 31.25 vol% and 40.04 wt%, which lowered the quality of the bio-oil. Those consequences also determined that a mixture of sludge with different ash/organic ratios could be pyrolyzed to obtain high-quality bio-fuels and high energy efficiency. Differences in C/H/O ratios in the mixed sludge greatly affected the microwave pyrolysis heating process, which affected the pyrolysis reactions and the quality of the bio-fuels. Therefore, this study provides a theoretical basis to elevate the quality of bio-fuels and reduce microwave pyrolysis costs.


Assuntos
Pirólise , Esgotos , Biocombustíveis , Temperatura Alta , Micro-Ondas , Temperatura
9.
J Comput Assist Tomogr ; 44(5): 744-749, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32842063

RESUMO

PURPOSE: The aim of this study was to investigate the diagnostic accuracy of computed tomography (CT) for the prediction of ablation zones from microwave ablation (MWA) and cryoablation (CA) in an ex vivo porcine liver model. METHODS: Sequential (30 seconds) CT scans were acquired during and after MWA and CA in an ex vivo porcine liver model. We generated 120-kVp equivalent reconstructions of generic dual-energy CT data sets, and comprehensive region-of-interest measurements were statistically correlated with invasive temperature monitoring using Pearson correlation coefficient. Binary logistic regression was performed for prediction of successful ablation. RESULTS: With the use of pooled data from 6 lesions in 2 separate experiments, correlation analysis of attenuation in Hounsfield units (HU) and temperature yielded r = -0.79 [confidence interval (CI), -0.85 to -0.71] for MWA and r = 0.62 (CI, 0.55 to 0.67) for CA.For MWA, there was a linear association between attenuation and temperature up to 75°C; thus, linear regression yielded a slope of -2.00 HU/°C (95% CI, -1.58 to -2.41). For CA, a linear association between attenuation and temperature was observed in the cooling phase with a slope of 2.11 HU/°C (95% CI, 1.79 to 2.58). In MWA treatment, binary logistic regression separated less than 70°C and greater than 70°C with 89.2% accuracy. Within the ice ball, temperatures above and below -20°C were distinguished with 65.3% accuracy. CONCLUSIONS: Our experiments reveal several difficulties in predicting ablation zone temperature from CT attenuation. Microwave ablation leads to gas production in the tissue, which degrades the accuracy of noninvasive temperature measurement, especially at higher temperatures. In CA, CT thermometry is limited by ice ball formation, which leads to homogeneous attenuation, nearly independent of temperature. Further research is needed to define the role of CT thermography in ablation zone monitoring in liver malignancies.


Assuntos
Técnicas de Ablação/métodos , Termografia/métodos , Tomografia Computadorizada por Raios X/métodos , Animais , Criocirurgia , Fígado/diagnóstico por imagem , Fígado/cirurgia , Micro-Ondas , Suínos
10.
PLoS One ; 15(8): e0237391, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32857786

RESUMO

Microwave heating of foods may alter their content. Yet, parents commonly heat infant formula in the microwave oven. The study aimed at understanding whether microwave heating of formula changes its fatty acid (FA) composition. Portions of infant formula were prepared and divided in three parts: control (sampled twice: at the start and after 30 minutes), microwave (sampled twice: after reaching 37°C and 50°C), and water bath (sampled twice: after reaching 37°C and 50°C). In thus obtained samples, a total profile of 25 FA was assessed using gas chromatography-mass spectrometry. Overall, fourteen portions were prepared, which were sampled 84 times yielding 2075 individual total FA level measurements. Few differences were identified between the microwave, control, and water bath groups. Microwave warming to 37°C was associated with increases of C12 (median increased by +0.40%, p = 0.0063), C14 (+0.05%, p = 0.0091), and C4 content (+6.90%, p = 0.0131). Microwaving up to 50°C slightly decreased C16:1trans (-5.00%, p = 0.0463) and C18:2trans1 (-5.13%, p = 0.0231). A paired comparison of pooled control and microwaved samples revealed increases in C12 (+0.18%, p = 0.0490) as well as a loss of C18:2trans1 (also -5.13%, p = 0.0073) and C18:2trans3 (-5.56%, p = 0.0042) after microwave treatment. C18:2trans1 (-2.63%, p = 0.0132) and C18:3trans1 (-2.26%, p = 0.0434) were lower in microwaved samples compared with the water bath. A slightly lower C18:2 content was found in the water bath samples than in the control groups (-0.11%, p = 0.0430). None of these differences would remain significant after a correction for multiple comparisons. Microwave heating of infant formula to 37°C or 50°C might marginally alter its total FA profile. Further studies are required to determine whether it alters the rate of free radical formation.


Assuntos
Ácidos Graxos/análise , Temperatura Alta , Fórmulas Infantis/química , Micro-Ondas , Ácidos Graxos/química , Humanos , Lactente
11.
J Hosp Infect ; 106(1): 10-19, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32652212

RESUMO

BACKGROUND: In the wake of the SARS-CoV-2 pandemic and unprecedented global demand, clinicians are struggling to source adequate access to personal protective equipment. Respirators can be in short supply, though are necessary to protect workers from SARS-CoV-2 exposure. Rapid decontamination and reuse of respirators may provide relief for the strained procurement situation. METHOD: In this study, we investigated the suitability of 70°C dry heat and microwave-generated steam (MGS) for reprocessing of FFP2/N95-type respirators, and Type-II surgical face masks. Staphylococcus aureus was used as a surrogate as it is less susceptible than enveloped viruses to chemical and physical processes. RESULTS: We observed >4 log10 reductions in the viability of dry S. aureus treated by dry heat for 90 min at 70°C and >6 log10 reductions by MGS for 90 s. After 3 reprocessing cycles, neither process was found to negatively impact the bacterial or NaCl filtration efficiency of the respirators that were tested. However, MGS was incompatible with Type-II surgical masks tested, as we confirmed that bacterial filtration capacity was completely lost following reprocessing. MGS was observed to be incompatible with some respirator types due to arcing observed around some types of metal nose clips and by loss of adhesion of clips to the mask. CONCLUSION: Considering the advantages and disadvantages of each approach, we propose a reprocessing personal protective equipment/face mask workflow for use in medical areas.


Assuntos
Infecções por Coronavirus/prevenção & controle , Descontaminação/métodos , Reutilização de Equipamento/normas , Temperatura Alta , Máscaras/virologia , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Dispositivos de Proteção Respiratória/virologia , Vapor , Betacoronavirus , Guias como Assunto , Humanos , Micro-Ondas
12.
Environ Sci Pollut Res Int ; 27(31): 39186-39197, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32638310

RESUMO

Adsorption and photocatalysis are promising strategies to remove pollutants of dyes and antibiotics from wastewater. In this study, we demonstrate a rapid microwave-assisted hydrothermal route for the assembly of 2D copper-porphyrin Metal-Organic Frameworks (Cu-TCPP MOFs) within 1 h. The resulting 2D Cu-TCPP nanosheets with excellent crystallinity and a large surface area (342.72 m2/g) exhibited outstanding adsorption performance for typical dyes with adsorption capacities of about 185 mg/g for rhodamine B, 625 mg/g for methylene blue, and 290 mg/g for Congo red, respectively, as well as for representative antibiotics with adsorption capacities of about 130 mg/g for oxytocin, 150 mg/g for tetracycline, and 50 mg/g for norfloxacin, respectively. Meanwhile, the as-prepared 2D Cu-TCPP showed good photocatalytic degradation activity of pollutants after adsorption under irradiation by visible light, reaching removal efficiencies of 81.2 and 86.3% toward rhodamine B and norfloxacin, respectively. These results demonstrate the promising potential of 2D Cu-TCPP for use in the removal of contaminants from wastewater.


Assuntos
Estruturas Metalorgânicas , Porfirinas , Poluentes Químicos da Água/análise , Antibacterianos , Corantes , Cobre , Micro-Ondas , Água
13.
Clin Imaging ; 67: 146-151, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32659600

RESUMO

PURPOSE: To compare percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) for treatment of Hepatocellular carcinoma (HCC) and to identify risk factors for treatment failure and local progression. METHODS: 145 unique HCC [87 (60%) RFA, 58 (40%) MWA] were retrospectively reviewed from a single tertiary medical center. Adverse events were classified as severe, moderate, or mild according to the Society of Interventional Radiology Adverse Event Classification system. Primary and secondary efficacy, as well as local progression, were determined using mRECIST. Predictors of treatment failure and time to local progression were analyzed using generalized estimating equations and Cox regression, respectively. RESULTS: Technical success was achieved in 143/145 (99%) HCC. There were 1 (0.7%) severe and 2 (1.4%) moderate adverse events. Of the 143 technically successful initial treatments, 136 (95%) completed at least one follow-up exam. Primary efficacy was achieved in 114/136 (84%). 9/22 (41%) primary failures underwent successful repeat ablation, so secondary efficacy was achieved in 128/136 (90%) HCC. Local progression occurred in 24 (19%) HCC at a median of 25 months (95% CI = 19-32 months). There was no difference in technical success, primary efficacy, or time to local progression between RFA and MWA. In HCC treated with MWA, same-day biopsy was associated with primary failure (RR = 9.0, 95% CI: 1.7-47, P = 0.015), and proximity to the diaphragm or gastrointestinal tract was associated with local progression (HR = 2.40, 95% CI:1.5-80, P = 0.017). CONCLUSION: There was no significant difference in primary efficacy or time to local progression between percutaneous RFA and MWA.


Assuntos
Carcinoma Hepatocelular/terapia , Ablação por Cateter , Micro-Ondas , Ablação por Radiofrequência , Biópsia , Carcinoma Hepatocelular/patologia , Progressão da Doença , Feminino , Humanos , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Falha de Tratamento , Resultado do Tratamento
14.
Food Chem ; 332: 127407, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32645677

RESUMO

This study aimed to investigate the difference between ginger slices (vertically cut) and splits (horizontally cut) during microwave-vacuum drying (MVD) procedures. MVD ginger slices showed a higher shrinkage rate and a higher hardness value, with a more porous structure of the surface layer. MVD ginger splits had higher rehydration rates at the first 15 min of the rehydration. Nine optimal wavelengths were selected by regression coefficients (RC) from the partial least squares regression (PLSR) model based on the raw data. A simplified PLSR model based on optimal wavelengths showed a good performance with a coefficient of determination in prediction (Rp2) of 0.973 and a root mean square error in prediction (RMSEP) of 4.63%. Texture features of grey level co-occurrence matrix (GLCM) of moisture prediction maps demonstrated a more uniform moisture distribution in MVD ginger slices than that in splits in the original geometry.


Assuntos
Dessecação/métodos , Gengibre/fisiologia , Micro-Ondas , Gengibre/química , Análise dos Mínimos Quadrados , Microscopia Eletrônica de Varredura , Vácuo , Água/química
15.
Environ Sci Pollut Res Int ; 27(32): 40787-40794, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32677014

RESUMO

Studies from our group and others have reported that 30 mW/cm2 microwave could damage the structures of rat hippocampus, as well as impair the neuronal functions. The neuroprotective effects of astragaloside, purified from Astragalus membranaceus, have been demonstrated in animal models of neurodegenerative diseases. In this study, we found that 30 mW/cm2 microwave impaired spatial learning and memory ability in rats, while astragaloside could significantly alleviate the injuries. The pathological analysis also showed that astragaloside protected neurons from microwave-induced damages, such as mitochondrial swelling and cavitation, rough endoplasmic reticulum swelling and dilation, synaptic gap disappearing, and vesicle aggregation. Moreover, microwave-induced structural damage of synapse resulted in downregulation of acetylcholine, an important neurotransmitter for information transmission, while astragaloside could protect the structure of synapse, as well as restore the acetylcholine level in rat hippocampus. Furthermore, astragaloside also accelerated the recovery of brain electroencephalogram (EEG) after microwave exposure, indicating that astragaloside could promote the normalization of neuronal functions. In conclusion, astragaloside protected the morphological structures and restored acetylcholine level in rat hippocampus, which could improve brain functions via normalizing brain EEG. Therefore, astragaloside might be a promising candidate to treat microwave-induced injuries of central nervous system (CNS).


Assuntos
Saponinas , Triterpenos , Acetilcolina , Animais , Encéfalo , Eletroencefalografia , Memória , Micro-Ondas , Ratos , Saponinas/farmacologia , Triterpenos/farmacologia
18.
Bioresour Technol ; 314: 123756, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32629378

RESUMO

In light of the knowledge gap in the scale-up of microwave-assisted pyrolysis technology, this study developed a continuous microwave-assisted pyrolysis (CMAP) system and examined its feasibility for syngas production. Wood pellets were pyrolyzed in the system under various temperatures, and the product distribution and energy efficiency were investigated. At a processing temperature of 800 °C, the CMAP system obtained a high quality producer gas (lower heating value 18.0 MJ/Nm3 and a 67 vol% syngas content) at a yield of 72.2 wt% or 0.80 Nm3/kg d.a.f. wood, outperforming several conventional pyrolysis processes probably due to two factors: 1) reactions between primary tar and biochar enhanced by microwave irradiation, and 2) the absence of carrier gas in the process. Energy efficiency of the process was also assessed. Potentially the electricity consumption could be reduced from 7.2 MJ to 3.45 MJ per kg of wood, enabling net electricity production from the process.


Assuntos
Micro-Ondas , Pirólise , Biomassa , Temperatura Alta , Temperatura , Madeira
19.
Bioresour Technol ; 314: 123770, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32652448

RESUMO

Microalgae harvesting is a major hindrance for the development of the microalgae industry. In this paper, short microwave treatment was used to assist the flocculation of Chlorella vulgaris with three flocculants, Fe3+ (FeCl3), chitosan, and Ca2+ (CaCl2). A microwave irradiation time of 20 s, and a pH of 10 was found to be the optimum condition. The harvesting efficiency could be significantly increased by 43.2%, 49.5% and 39.6%, respectively for Fe3+, chitosan, and Ca2+ assisted by microwave under these conditions. Microwave treatment did not cause any damage to the algal cells, and had no obvious influence on the lipid extraction. Microwave treatment decreased the concentration of the flocculants in culture medium after flocculation; this treatment enabled the reuse of the supernatant. This study provides a new and promising method of improving the flocculation efficiency for microalgae harvesting, by using microwave energy.


Assuntos
Chlorella vulgaris , Microalgas , Biomassa , Floculação , Lipídeos , Micro-Ondas
20.
Zhongguo Zhong Yao Za Zhi ; 45(9): 2073-2081, 2020 May.
Artigo em Chinês | MEDLINE | ID: mdl-32495556

RESUMO

The iterative innovation of processing technology is one of the important tasks in studies on processing of traditional Chinese medicine(TCM). It is also the prerequisite for modern, refined, automatic and intelligent manufacturing of TCM pieces. Microwave processing is a new fire processing technique developed in the recent 30 years, with a unique thermodynamic form, and energy transfer and transformation laws. Moreover, it owns the advantages of a high processing efficiency, good product properties and low production energy consumption, with great application prospects. This paper introduced the study overview of microwave expansion technology in the food industry, reviewed the origin of microwave processing technology of TCM, and expounded the basic concept, principle and main purpose of microwave processing technology used in TCM. Then, the impacts of drug factors and microwave factors on the microwave processing effect were summarized, the industrial equipment that could be used for microwave processing was listed, and the impacts of microwave heating on starch, polysaccharide, protein and other components in Chinese herbal medicines were analyzed. Furthermore, the study advance of microwave processing of 14 herbs was investigated, including Aconiti Lateralis Radix Praeparaia, Galli Gigerii Endothelium Corneum and Asini Corii Colla; and the appearance and components of herbs processed by traditional processing method and microwave processing method were compared, so as to reveal the opportunities and challenges of microwave processing technology in the industrial transformation. We hoped that the systematic study of microwave processing technology could provide new ideas and techniques for the high-quality and high-level development of the TCM pieces industry in the new era, and promote its inheritance, innovation and transformation.


Assuntos
Aconitum , Medicamentos de Ervas Chinesas , Medicina Tradicional Chinesa , Micro-Ondas , Controle de Qualidade
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