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1.
J Orthop Sci ; 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38519378

RESUMO

INTRODUCTION: Hip fractures are commonly associated with osteoporosis and pose a risk for secondary fractures. Although the administration of anti-osteoporotic drugs is recommended after fractures to mitigate this risk, the potential effect of strong anti-resorptive drugs (e.g., denosumab) on fracture healing processes have not been extensively studied. This prospective study aimed to evaluate the feasibility of early denosumab administration after femoral intertrochanteric fracture surgery and to compare its effect on fracture healing to that of bisphosphonate-treated patients. MATERIALS AND METHODS: Patients who underwent surgery for intertrochanteric femoral fragility fractures between November 2018 and November 2020 were prospectively examined. Patients were randomized into two groups (denosumab [DSM] and ibandronate [IBN] groups) using a simple randomization procedure. Physical findings, plain radiographs, and computed tomography (CT) were used to evaluate fracture healing at 3 months postoperatively. RESULTS: Physical findings showed no significant differences between the two groups in pain on loading, tenderness at fracture site, or walking ability. There were inter-rater differences in radiological fracture healing rate: plain radiographs, 57.5%-81.8% in the DSM group and 51.5%-90.9% in the IBN group; CT, 51.5%-72.7% in the DSM group and 45.4%-81.8% in the IBN group. Although there were variations, there were no significant differences in the fracture healing rate between groups on plain radiographs or CT among all three raters. CONCLUSIONS: Early administration of denosumab after intertrochanteric femoral fracture surgery did not delay radiological or clinical fracture healing times when compared with ibandronate administration.

2.
Int J Mol Sci ; 25(13)2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38999942

RESUMO

Familial episodic pain syndrome (FEPS) is an early childhood onset disorder of severe episodic limb pain caused mainly by pathogenic variants of SCN11A, SCN10A, and SCN9A, which encode three voltage-gated sodium channels (VGSCs) expressed as key determinants of nociceptor excitability in primary sensory neurons. There may still be many undiagnosed patients with FEPS. A better understanding of the associated pathogenesis, epidemiology, and clinical characteristics is needed to provide appropriate diagnosis and care. For this study, nationwide recruitment of Japanese patients was conducted using provisional clinical diagnostic criteria, followed by genetic testing for SCN11A, SCN10A, and SCN9A. In the cohort of 212 recruited patients, genetic testing revealed that 64 patients (30.2%) harbored pathogenic or likely pathogenic variants of these genes, consisting of 42 (19.8%), 14 (6.60%), and 8 (3.77%) patients with variants of SCN11A, SCN10A, and SCN9A, respectively. Meanwhile, the proportions of patients meeting the tentative clinical criteria were 89.1%, 52.0%, and 54.5% among patients with pathogenic or likely pathogenic variants of each of the three genes, suggesting the validity of these clinical criteria, especially for patients with SCN11A variants. These clinical diagnostic criteria of FEPS will accelerate the recruitment of patients with underlying pathogenic variants who are unexpectedly prevalent in Japan.


Assuntos
Testes Genéticos , Canal de Sódio Disparado por Voltagem NAV1.7 , Canal de Sódio Disparado por Voltagem NAV1.8 , Canal de Sódio Disparado por Voltagem NAV1.9 , Humanos , Canal de Sódio Disparado por Voltagem NAV1.7/genética , Canal de Sódio Disparado por Voltagem NAV1.9/genética , Japão/epidemiologia , Canal de Sódio Disparado por Voltagem NAV1.8/genética , Masculino , Feminino , Testes Genéticos/métodos , Adulto , Adolescente , Criança , Predisposição Genética para Doença , Adulto Jovem , Pré-Escolar , Mutação , Dor , Reto/anormalidades
3.
Cell Mol Neurobiol ; 41(1): 31-42, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32180095

RESUMO

We examined the functional and structural changes of auditory neurons (ANs) in adult mice after conductive hearing loss (CHL). Earplugs (EPs) were bilaterally inserted in male 8-week-old mice for 4 weeks [EP(+) group] and subsequently removed for 4 weeks [EP(+/-) group]. We examined the control mice [EP(-) group] with no EPs inserted at 12 weeks. The auditory brainstem response (ABR) was measured to determine the cochlear function before and after EP insertion, after EP removal, and at 4 weeks following EP removal. We examined the cochleae for hair cell (HC) and spiral ganglion neuron survival, synaptic and neural properties, and AN myelination. There was a significant elevation of the ABR threshold across all tested frequencies after EP insertion. After removing the occlusion, these threshold shifts were fully recovered. Compared with the EP(-) mice, the EP(+) mice showed a significant decrease in the ABR peak 1 amplitude and a significantly prolonged latency at all tested frequencies. There was no significant effect of auditory deprivation on the survival of HCs and ANs. Conversely, auditory deprivation caused significant damage to the synapses and myelin and a significant decrease in the AN size. Although functional changes in the ABR amplitude and latency did not fully recover in the EP(+/-) mice, almost all anatomical changes were fully recovered in the EP(+/-) mice; however, cochlear synapses only showed partial recovery. These results suggest that auditory activities are required to maintain peripheral auditory synapses and myelination in adults. The auditory deprivation model allows for assessment of the mechanisms of synaptopathy and demyelination in the auditory periphery, and synaptic and myelin regeneration in sensorineural hearing loss.


Assuntos
Envelhecimento/patologia , Células Ciliadas Auditivas/patologia , Perda Auditiva Condutiva/patologia , Perda Auditiva Condutiva/fisiopatologia , Degeneração Neural/fisiopatologia , Plasticidade Neuronal , Oxirredutases do Álcool/metabolismo , Animais , Proteínas Correpressoras/metabolismo , Potenciais Evocados Auditivos do Tronco Encefálico , Masculino , Camundongos Endogâmicos C57BL , Bainha de Mielina/patologia , Degeneração Neural/patologia , Fibras Nervosas/patologia , Receptores de AMPA/metabolismo , Gânglio Espiral da Cóclea/patologia , Sinapses/metabolismo
4.
BMC Cancer ; 20(1): 25, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31914969

RESUMO

BACKGROUND: There are many types of therapies for cancer. In these days, immunotherapies, especially immune checkpoint inhibitors, are focused on. Though many types of immune checkpoint inhibitors are there, the difference of effect and its mechanism are unclear. Some reports suggest the response rate of anti-PD-1 antibody is superior to that of anti-PD-L1 antibody and could potentially produce different mechanisms of action. On the other hand, Treg also express PD-1; however, their relationship remains unclear. METHODS: In this study, we used osteosarcoma cell lines in vitro and osteosarcoma mouse model in vivo. In vitro, we analyzed the effect of IFNγ for expression of PD-L1 on the surface of cell lines by flowcytometry. In vivo, murine osteosarcoma cell line LM8 was subcutaneously transplanted into the dorsum of mice. Mouse anti-PD-1 antibody was intraperitoneally administered. we analysed the effect for survival of anti-PD-1 antibody and proportion of T cells in the tumour by flowcytometry. RESULTS: We discovered that IFNγ increased PD-L1 expression on the surface of osteosarcoma cell lines. In assessing the relationship between anti-PD-1 antibody and Treg, we discovered the administration of anti-PD-1 antibody suppresses increases in tumour volume and prolongs overall survival time. In the tumour microenvironment, we found that the administration of anti-PD-1 antibody decreased Treg within the tumour and increased tumour-infiltrating lymphocytes. CONCLUSIONS: Here we clarify for the first time an additional mechanism of anti-tumour effect-as exerted by anti-PD-1 antibody decreasing Treg- we anticipate that our findings will lead to the development of new methods for cancer treatment.


Assuntos
Antineoplásicos Imunológicos/farmacologia , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Linfócitos do Interstício Tumoral/metabolismo , Neoplasias/imunologia , Neoplasias/metabolismo , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/metabolismo , Animais , Antineoplásicos Imunológicos/uso terapêutico , Linhagem Celular Tumoral , Modelos Animais de Doenças , Expressão Gênica , Humanos , Interferon gama/metabolismo , Linfócitos do Interstício Tumoral/imunologia , Camundongos , Neoplasias/mortalidade , Neoplasias/patologia , Prognóstico , Receptor de Morte Celular Programada 1/genética , Receptor de Morte Celular Programada 1/metabolismo , Linfócitos T Reguladores/imunologia , Resultado do Tratamento , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/imunologia , Ensaios Antitumorais Modelo de Xenoenxerto
5.
Plant Cell Physiol ; 60(1): 126-138, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30295899

RESUMO

Autophagy is a recycling system for amino acids and carbon- and nitrogen (N)-containing compounds. To date, the functional importance of autophagy in microalgae in nutrient-deficient conditions has not been evaluated by using autophagy-defective mutants. Here, we provide evidence which supports the following notions by characterizing an insertional mutant of the autophagy-related gene ATG8, encoding a ubiquitin-like protein necessary for the formation of the autophagosome in the green alga, Chlamydomonas reinhardtii. First, ATG8 is required for maintenance of cell survival and Chl content in N-, sulfur- and phosphate-deficient conditions. Secondly, ATG8 supports the degradation of triacylglycerol and lipid droplets after the resupply of N to cells cultured in N-limiting conditions. Thirdly, ATG8 is also necessary for accumulation of starch in phosphate-deficient conditions. Additionally, autophagy is not essential for maternal inheritance of the organelle genomes in gametogenesis.


Assuntos
Autofagia , Chlamydomonas/genética , Mutação/genética , Nitrogênio/deficiência , Fosfatos/deficiência , Enxofre/deficiência , Proteínas Relacionadas à Autofagia/metabolismo , Carbono/metabolismo , Sobrevivência Celular , Chlamydomonas/metabolismo , Clorofila/metabolismo , Lipídeos/química , Fenótipo , Ubiquitina/metabolismo
7.
No To Hattatsu ; 48(4): 247-51, 2016 Jul.
Artigo em Japonês | MEDLINE | ID: mdl-30010305

RESUMO

Objective: To elucidate the pathophysiology of West syndrome and mechanism of immunoglobulin therapy for this syndrome, we investigated serum and cerebrospinal fluid (CSF) cytokine levels before and after high-dose intravenous immunoglobulin (IVIG) therapy in patients with West syndrome. Methods: We measured serum and CSF cytokine levels of 11 patients with West syndrome who was referred to Saitama Children's Medical Center from April 2010 to May 2014. All patients received IVIG, ranging from 200 to 500 mg/kg/day for 3 consecutive days (initial IVIG treatment), before adrenocorticotrophic hormone therapy. When spasms disappeared within 2 weeks after initial IVIG treatment, maintenance IVIG treatment was commenced. We measured cytokines level in patients before and after initial IVIG treatment. We compared the levels of cytokines (IL-1ß, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-17, Interferon γ, Granulocyte macrophage colony stimulating factor, IL-18, Tumor necrosis factor-α〔TNF-α〕) in serum and CSF, and between the seizure-free group and seizure-persisting group. Seizure free was defined as remission of spasms within 2 weeks after initial IVIG treatment and no relapse for at least 1 week after remission. Results: After IVIG therapy, 5 of 11 patients were in the seizure-free group (4 males, 1 cryptogenic) while 6 were in the seizure-persisting group (2 males, 1 cryptogenic). Levels of IL-1ß, IL-10, IL-18, and TNF-α in serum were significantly higher than those in CSF before initiation of IVIG. Before IVIG treatment, the level of IL-8 in CSF was significantly higher than that in serum, while the serum IL-18 level in the seizure-free group was significantly lower than that in the seizure-persisting group. Alterations of serum IL-18 level and CSF IL-8 level were different between the seizure-free and seizure-persisting groups. Conclusions: Serum IL-18 and CSF IL-8 may be important factors for elucidating the pathophysiology of West syndrome and mechanism of IVIG therapy.


Assuntos
Citocinas/sangue , Citocinas/líquido cefalorraquidiano , Imunização Passiva , Imunoglobulinas Intravenosas/uso terapêutico , Espasmos Infantis/tratamento farmacológico , Feminino , Humanos , Lactente , Masculino
9.
PLoS One ; 19(4): e0300842, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38598429

RESUMO

Maze-solving is a classical mathematical task, and is recently analogously achieved using various eccentric media and devices, such as living tissues, chemotaxis, and memristors. Plasma generated in a labyrinth of narrow channels can also play a role as a route finder to the exit. In this study, we experimentally observe the function of maze-route findings in a plasma system based on a mixed discharge scheme of direct-current (DC) volume mode and alternative-current (AC) surface dielectric-barrier discharge, and computationally generalize this function in a reinforcement-learning model. In our plasma system, we install two electrodes at the entry and the exit in a square lattice configuration of narrow channels whose cross section is 1×1 mm2 with the total length around ten centimeters. Visible emissions in low-pressure Ar gas are observed after plasma ignition, and the plasma starting from a given entry location reaches the exit as the discharge voltage increases, whose route converging level is quantified by Shannon entropy. A similar short-path route is reproduced in a reinforcement-learning model in which electric potentials through the discharge voltage is replaced by rewards with positive and negative sign or polarity. The model is not rigorous numerical representation of plasma simulation, but it shares common points with the experiments along with a rough sketch of underlying processes (charges in experiments and rewards in modelling). This finding indicates that a plasma-channel network works in an analog computing function similar to a reinforcement-learning algorithm slightly modified in this study.


Assuntos
Líquidos Corporais , Reforço Psicológico , Recompensa , Plasma , Algoritmos
10.
PLoS One ; 19(1): e0297443, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38277391

RESUMO

There has been only limited success to differentiate adult stem cells into cardiomyocyte subtypes. In the present study, we have successfully induced beating atrial and ventricular cardiomyocytes from rat hair-follicle-associated pluripotent (HAP) stem cells, which are adult stem cells located in the bulge area. HAP stem cells differentiated into atrial cardiomyocytes in culture with the combination of isoproterenol, activin A, bone morphogenetic protein 4 (BMP4), basic fibroblast growth factor (bFGF), and cyclosporine A (CSA). HAP stem cells differentiated into ventricular cardiomyocytes in culture with the combination of activin A, BMP4, bFGF, inhibitor of Wnt production-4 (IWP4), and vascular endothelial growth factor (VEGF). Differentiated atrial cardiomyocytes were specifically stained for anti-myosin light chain 2a (MLC2a) antibody. Ventricular cardiomyocytes were specially stained for anti-myosin light chain 2v (MLC2v) antibody. Quantitative Polymerase Chain Reaction (qPCR) showed significant expression of MLC2a in atrial cardiomyocytes and MLC2v in ventricular cardiomyocytes. Both differentiated atrial and ventricular cardiomyocytes showed characteristic waveforms in Ca2+ imaging. Differentiated atrial and ventricular cardiomyocytes formed long myocardial fibers and beat as a functional syncytium, having a structure similar to adult cardiomyocytes. The present results demonstrated that it is possible to induce cardiomyocyte subtypes, atrial and ventricular cardiomyocytes, from HAP stem cells.


Assuntos
Miócitos Cardíacos , Células-Tronco Pluripotentes , Ratos , Animais , Miócitos Cardíacos/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Folículo Piloso , Diferenciação Celular , Suplementos Nutricionais
11.
Masui ; 62(4): 495-9, 2013 Apr.
Artigo em Japonês | MEDLINE | ID: mdl-23697210

RESUMO

BACKGROUND: Fresh frozen plasma (FFP) should be thawed in a water bath at 30-37 degrees C. Suitable temperature, the prevention for bacterial contamination, and the efficiency of the process are necessary for a thawing procedure. In this study, we compared the clotting factor activity and thawing time in different thawing procedures; a water bath, the thermostatic thawing chamber (FP-40, Hokuyo ; Kawasumi, Japan), and the microwave system (Transfusio-therm 2000 AMCO; Zeipel, Germany). METHODS: Thawing time and the clotting factor activity (prothrombin time: PT, prothrombin time-international normalized ratio: PT-INR, activated partial thromboplastin time: APTT, fibrinogen, andfactors V) of thawed FFP-5 units were measured. RESULTS: Thawing time using Transfusio-therm 2000 was 11.4 minutes, which was faster than that using the water bath and FP-40 of about 39.5 and 27.3 minutes, respectively (P<0.01). There were no differences between the three methods in terms of the clotting factors. CONCLUSIONS: The microwave system is useful in shortening the time safety, and maintaining the clotting factor activity in thawed FFP


Assuntos
Fatores de Coagulação Sanguínea/fisiologia , Plasma , Humanos , Micro-Ondas , Tempo de Protrombina , Fatores de Tempo
12.
Materials (Basel) ; 16(7)2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-37049193

RESUMO

Droplet ejections from a molten tungsten electrode during alternating current tungsten inert gas (AC TIG) welding were observed successfully by a high-speed video captured at 75,000 fps. The welding conditions and timings that were likely to occur were investigated. The electrode surface temperature was also measured. A crater was formed on the surface of the electrode, and a droplet ejection occurred following the separation of the tip of the ridge growing from the centre of the crater. A series of droplet ejections occurred on a time scale of approximately 0.4 ms. Our results showed that the high temperature of the electrode surface was the common factor for droplet ejections. The dominant force for droplet ejection was discussed by estimating the balance of forces acting on the molten electrode surface. The pressure due to surface tension was the largest pressure at any time during the AC cycle, which decreased in the second half of the EP period. Our findings suggest that the surface tension was the dominant force for changing the electrode shape and that droplet ejections occurred when the surface tension decreased due to the increase in the electrode surface temperature.

13.
Sci Rep ; 13(1): 12210, 2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37500733

RESUMO

A unique mechanism of splashing from a tungsten-based anode was identified during arc discharge. Splashing occurred by breakoff of a liquid metal column, which elongates after a local concavity formed on the molten anode surface. Blue-violet luminescence, emitted by cerium ions originating from additives in the tungsten-based anode, was captured before the concavity formation. The surface temperature exceeded the boiling point of the additives at the time of splashing. The measured droplet speeds suggested that an electromagnetic force contributes the high-speed ejections. Energy dispersive spectrometry mapping also exhibited a remnant of the additives on the longitudinal cross-section of the anode after arc discharge. Based on these experimental facts, the mechanism of anode splashing in arc discharge was deduced as follows: bubble formation of additives at temperatures above their boiling point, bubble bursting at the surface, micro-plasma jet generation, liquid-column elongation and breakoff under an electromagnetic force, and consequent high-speed droplet ejection.

14.
Materials (Basel) ; 16(8)2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37109890

RESUMO

This study aimed to clarify the effect of wire structure and alkaline elements in wire composition on metal transfer behavior in metal-cored arc welding (MCAW). A comparison of metal transfer in pure argon gas was carried out using a solid wire (wire 1), a metal-cored wire without an alkaline element (wire 2), and another metal-cored wire with 0.084 mass% of sodium (wire 3). The experiments were conducted under 280 and 320 A welding currents, observed by high-speed imaging techniques equipped with laser assistance and bandpass filters. At 280 A, wire 1 showed a streaming transfer mode, while the others showed a projected one. When the current was 320 A, the metal transfer of wire 2 changed to streaming, while wire 3 remained projected. As sodium has a lower ionization energy than iron, the mixing of sodium vapor into the iron plasma increases its electrical conductivity, raising the proportion of current flowing through metal vapor plasma. As a result, the current flows to the upper region of the molten metal on the wire tip, with the resulting electromagnetic force causing droplet detachment. Consequently, the metal transfer mode in wire 3 remained projected. Furthermore, weld bead formation is the best for wire 3.

15.
Dev Growth Differ ; 54(8): 753-66, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23067137

RESUMO

Previously, we revealed that p58, one of the ascidian maternal factors, is identical to the alpha-subunit of F1-ATP synthase (ATPα), a protein complex of the inner mitochondrial membrane. In the current study, we used immunological probes for ascidian mitochondria components to show that the ascidian ATPα is ectopically localized to the cytosol. Virtually all mitochondrial components were localized to the mitochondria-rich myoplasm. However, in detail, ATP synthase subunits and the matrix proteins showed different localization patterns. At least at the crescent stage, transmission electron microscopy (TEM) distinguished the mitochondria-less, endoplasmic reticulum (ER)-rich cortical region and the mitochondria-rich internal region. ATPα was enriched in the cortical region and MnSOD was limited to the internal region. Using subcellular fractionation, although all of the mitochondria components were highly enriched in the mitochondria-enriched fraction, a considerable amount of ATPα and F1-ATP synthase beta-subunit (ATPß) were recovered in the insoluble cytoplasmic fraction. Even under these conditions, F1-ATP synthase gamma-subunit (ATPγ) and F0-ATP synthase subunit b (ATPb) were not recovered in the insoluble cytoplasmic fraction. This result strongly supports the exomitochondrial localization of both ATPα and ATPß. In addition, the detergent extraction of eggs supports the idea that these cytosolic ATP synthase subunits are associated with the egg cytoskeleton. These results suggest that the subunits of ATP synthase might play dual roles at different subcellular compartments during early development.


Assuntos
Ciona intestinalis/enzimologia , Citosol/enzimologia , Retículo Endoplasmático/enzimologia , Mitocôndrias/enzimologia , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Óvulo/enzimologia , Animais , Ciona intestinalis/citologia , Ciona intestinalis/embriologia , Citoesqueleto/enzimologia , Oogênese/fisiologia , Óvulo/ultraestrutura
16.
Epilepsia ; 53(1): 79-86, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22092154

RESUMO

PURPOSE: The occurrence of acute encephalopathy in children with Dravet syndrome has been reported sporadically. This study clarified the features of acute encephalopathy in children with Dravet syndrome. METHODS: Through the mailing list of the Annual Zao Conference on Pediatric Neurology, we collected 15 patients with clinically diagnosed Dravet syndrome, who had acute encephalopathy, defined as a condition with decreased consciousness with or without other neurologic symptoms, such as seizures, lasting for >24 h in association with infectious symptoms. KEY FINDINGS: There were seven boys and eight girls. A mutation of the SCN1A gene was present in nine (truncation in six and missense in three). The frequency of seizures during the 3 months before the onset of acute encephalopathy was monthly in seven children and none in three. The median age at the onset of acute encephalopathy was 44 months (range 8-184 months). All children had status epilepticus followed by coma as the initial manifestation. Two different distributions of brain lesions were observed on diffusion-weighted images during the acute phase: cerebral cortex-dominant lesions with or without deep gray matter involvement and subcortical-dominant lesions. Four children died; nine survived with severe sequelae, and two had moderate sequelae. SIGNIFICANCE: We must be aware that acute encephalopathy is an important complication in children with Dravet syndrome, and associated with fulminant clinical manifestations and a poor outcome.


Assuntos
Córtex Cerebral/patologia , Deficiência Intelectual/etiologia , Deficiência Intelectual/patologia , Imageamento por Ressonância Magnética , Proteínas do Tecido Nervoso/genética , Convulsões/complicações , Canais de Sódio/genética , Espasmos Infantis/etiologia , Espasmos Infantis/patologia , Doença Aguda , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Deficiência Intelectual/fisiopatologia , Síndrome de Lennox-Gastaut , Masculino , Mutação , Canal de Sódio Disparado por Voltagem NAV1.1 , Convulsões/genética , Convulsões/patologia , Espasmos Infantis/fisiopatologia , Síndrome
17.
J Hazard Mater ; 430: 128381, 2022 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-35149488

RESUMO

Pyridine is a basic heterocyclic compound with high toxicity, widely found in liquid waste from industrial processes. The treatment of highly-concentrated pyridine was demonstrated using a novel mist-type water thermal plasma torch. Decomposition rate and TOC removal rate were more than 94% in all conditions, while the max energy efficiency reached about 23 g/kWh. With a high temperature of 5500-7500 K, more than 95% of carbon content in pyridine was converted into valuable gas products, while a little amount of formic acid and acetic acid were observed as liquid by-products. The production of hydrogen cyanide (HCN) during the thermal decomposition of pyridine was observed, which can be inhibited by increasing the input power. Based on the experimental results, detailed decomposition mechanisms in the high-temperature and the downstream region were discussed respectively. Water plasma shows significant potential in the treatment of non-biodegradable industrial liquid waste.


Assuntos
Gases em Plasma , Poluentes Químicos da Água , Resíduos Industriais , Piridinas , Águas Residuárias , Água , Poluentes Químicos da Água/análise
18.
Chemosphere ; 307(Pt 3): 136056, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35973502

RESUMO

Water plasma coupled with mist generator was introduced to perform the decomposition of caffeine (CAF) wastewater. The mist-shaped water molecule was directly used for plasma-forming gas with no additional gas. The influence of arc current on the decomposition of CAF was elucidated in detail. With the increase of input power from 0.8 to 1.1 kW according to arc current, the removal efficiency of total organic carbon (TOC) and CAF increased, reaching 91.1 and 99.8% at 9.5 A, respectively. H2, CO, CO2, and N2 were major effluent gaseous species, of which the H2 generation was more than 40% for all conditions. The concentration of nitrate in the effluent liquids was the highest at 9.5 A due to a higher oxidation environment. The H, O, and OH as reactive species formed via the dissociation of water molecules were demonstrated, and the plasma temperatures were at over 5000 K. The detailed decomposition pathway was deduced based on eleven intermediate products identified in this process. Electron impact and hydroxyl radical were found to take leading roles in the decomposition of CAF.


Assuntos
Águas Residuárias , Água , Cafeína , Carbono , Dióxido de Carbono , Gases , Radical Hidroxila , Nitratos
19.
Materials (Basel) ; 15(9)2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35591506

RESUMO

A novel bypass coupling variable polarity plasma arc was proposed to achieve the accurate adjusting of heat and mass transfer in the welding and additive manufacturing of aluminum alloy. However, the physical characteristics and decoupled transfer behavior remain unclear, restricting its application and development. A three-dimensional model of the bypass coupling variable polarity plasma arc was built based on Kirchhoff's law, the main arc and the bypass arc are coupled by an electromagnetic field. The model of current attachment on the tungsten electrode surface is included for simulating different heating processes of the EP and EN phases in the coupling arc. The distribution of temperature field, flow field, and current density of the bypass coupling variable polarity plasma arc was studied by the three-dimensional numerical model. The heat input on the base metal under different current conditions is quantified. To verify the model, the arc voltages are compared and the results in simulation and experiment agree with each other well. The results show that the radius of the bypass coupling arc with or without bypass current action on the base metal is different, and the flow vector of the bypass coupling arc plasma with bypass current is larger than the arc without bypass current. By comparing the heat transfer on the electrodes' boundary under different current conditions, it is found that increasing the bypass current results in the rise in heat input on the base metal. Therefore, it is concluded that using bypass current is unable to completely decouple the wire melting and the heat input of the base metal. The decoupled degree of heat transfer is one of the important factors for accurate control in the manufacturing process with this coupling arc.

20.
Nanomaterials (Basel) ; 12(7)2022 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-35407313

RESUMO

Nanomaterials show great promise as bone regeneration materials. They can be used as fillers to strengthen bone regeneration scaffolds, or employed in their natural form as carriers for drug delivery systems. A variety of experiments have been conducted to evaluate the osteogenic potential of bone regeneration materials. In vivo, such materials are commonly tested in animal bone defect models to assess their bone regeneration potential. From an ethical standpoint, however, animal experiments should be minimized. A standardized in vitro strategy for this purpose is desirable, but at present, the results of studies conducted under a wide variety of conditions have all been evaluated equally. This review will first briefly introduce several bone regeneration reports on nanomaterials and the nanosize-derived caveats of evaluations in such studies. Then, experimental techniques (in vivo and in vitro), types of cells, culture media, fetal bovine serum, and additives will be described, with specific examples of the risks of various culture conditions leading to erroneous conclusions in biomaterial analysis. We hope that this review will create a better understanding of the evaluation of biomaterials, including nanomaterials for bone regeneration, and lead to the development of versatile assessment methods that can be widely used in biomaterial development.

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