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1.
Polymers (Basel) ; 15(7)2023 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-37050350

RESUMO

For anion exchange membrane water electrolysis (AEMWE), two types of anion exchange membranes (AEMs) containing crosslinked poly(phenylene oxide) (PPO) and poly(styrene ethylene butylene styrene) (SEBS) were prepared with and without triazole. The impact of triazole was carefully examined. In this work, the PPO was crosslinked with the non-aryl ether-type SEBS to take advantage of its enhanced chemical stability and phase separation under alkaline conditions. Compared to their triazole-free counterpart, the crosslinked membranes made with triazole had better hydroxide-ion conductivity because of the increased phase separation, which was confirmed by X-ray diffraction (XRD) and atomic force microscopy (AFM). Moreover, they displayed improved mechanical and alkaline stability. Under water electrolysis (WE) conditions, a triazole-containing crosslinked PPO-SEBS membrane electrode assembly (MEA) was created using IrO2 as the anode and a Pt/C catalyst as the cathode. This MEA displayed a current density of 0.7 A/cm2 at 1.8 V, which was higher than that of the MEA created with the triazole-free counterpart. Our study indicated that the crosslinked PPO-SEBS membrane containing triazoles had improved chemo-physical and electrical capabilities for WE because of the strong hydrogen bonding between triazole and water/OH-.

2.
Environ Res ; 183: 109162, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32018206

RESUMO

Meat-grilling restaurants are considered to be residential emission sources of air pollutants. To investigate the emission characteristics of particulate matter (PM), odors, and volatile organic compounds (VOCs) from the grilling of meat, a grilling apparatus equipped with butane gas burners was used to grill pork belly and marinated pork ribs in a laboratory setting. When grilling the pork belly, the emission factor for PM with a diameter of 2.5 µm or below (PM2.5) was 754 mg-PM·kg-meat-1, accounting for 99% of total suspended particles (TSPs), while that of the marinated pork ribs was 137 mg-PM·kg-meat-1 (96% of TSPs). Ammonia and acetaldehyde were the most common odors emitted during grilling at 43-88 mg·kg-meat-1 and 22-30 mg·kg-meat-1, respectively. Aldehydes were the most significant contributor to total odor intensity (36%-67%). Benzene, vinyl acetate, and hexene were the most abundant VOCs for the pork belly, while butane, vinyl acetate, and n-dodecane were the most abundant for the marinated ribs. Among the VOCs emitted from the pork grilling process, hexene, butane, and toluene were the dominant ozone precursors. The information obtained in this study is useful for furthering the understanding of the characteristics of air pollutants emitted from actual meat-grilling restaurants. Additionally, knowledge of the PM, odor, and VOC emission characteristics and their emission factors is useful for establishing management strategies for air pollutants from meat-grilling restaurants.


Assuntos
Poluentes Atmosféricos , Carne Vermelha , Compostos Orgânicos Voláteis , Animais , Monitoramento Ambiental , Odorantes , Material Particulado , Suínos
3.
RSC Adv ; 10(64): 39121-39129, 2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-35518442

RESUMO

For the removal of volatile organic compounds (VOCs) from environmental systems, gaseous benzene, a model VOC, was adsorbed on naturally Fe-containing activated carbon and subsequently, decomposed in the presence of de-ionized water, and low (0.03%, pH 6.5) and high (30%, pH 2.5) concentration H2O2 solutions. The intermediates produced during benzene decomposition were analyzed and compared using gas chromatography-mass spectrometry. After the decomposition process, the activated carbon sample was air dried. Three cycles were carried out with de-ionized water and low and high concentration H2O2 solutions as oxidants. The adsorption capacity of the activated carbon sample treated with DI water gradually decreased as the number of cycles increased. On the other hand, the benzene adsorption capacity of the activated carbon samples treated with the H2O2 solutions was improved due to the relatively higher specific surface areas of these samples. After treatment with the low-concentration H2O2 solution, intermediates such as glyoxylic acid, oxalic acid, phenol, malonic acid, and pyrocatechol were observed. After treatment with high-concentration H2O2 solution, intermediates such as glyoxylic acid, formic acid, and acetic acid were formed. With increasing H2O2 concentration, the number and the molecular weight of the intermediate formed by the oxidative degradation of benzene, simultaneously decreased. The Fenton reaction induced by naturally Fe-containing activated carbon and H2O2 could lead to more efficient decomposition of benzene.

4.
Int J Mol Sci ; 21(24)2020 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-33419292

RESUMO

In this study, hydrogen generation powder samples were prepared using zinc carbonate as a precursor, at a temperature varying from 400 to 700 °C in H2 atmosphere, and were characterized in terms of antioxidant activity. The concentration of dissolved hydrogen obtained by the powder samples was measured using a dissolved hydrogen meter as a function of time. In addition, the antioxidant activity of the samples was evaluated based on the Oyaizu's method, removal rate of ·OH radicals, and ferric reducing antioxidant power. Finally, the hydrogen mask pack was fabricated using the hydrogen generation powder sample and gel-type emulsion. In the clinical test on the mask pack, the effect of the mask on skin aging was characterized and compared to that of a commercial sample. The skin densities of the participants in the experimental group and the control group increased by 18.41% and 9.93% after 4 weeks, respectively. The improved skin density of the participants who used the hydrogen mask pack in the experimental group, might be attributed to the recovery effect of the hydrogen molecule in the mask pack on the denatured thick skin layer.


Assuntos
Antioxidantes/química , Carbonatos/química , Hidrogênio/química , Pele/efeitos dos fármacos , Compostos de Zinco/química , Antioxidantes/farmacologia , Emulsões/química , Emulsões/farmacologia , Humanos , Radical Hidroxila/química , Ferro/química , Pós/química , Pós/farmacologia , Pele/patologia , Envelhecimento da Pele/efeitos dos fármacos , Temperatura , Água/química
5.
ChemSusChem ; 10(10): 2202-2209, 2017 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-28296248

RESUMO

To develop doped carbon nanostructures as non-precious metal cathode catalysts, nanocomposites were synthesized by using SBA-15 and 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin-iron(III) chloride with different ratios of amorphous MoS2 precursor. From various analyses, it was found that, during pyrolysis at 900 °C under an N2 atmosphere, the amorphous MoS2 precursor decomposed into Mo and S, facilitating the formation of graphene sheet-like carbon with MoC and doping of sulfur in the carbon. In the nanocomposite formed from 10 wt % MoS2 precursor (denoted as Mo/S/PC-10), most of the MoS2 was decomposed, thus forming S-doped carbon, which was grown on the MoC phase without crystalline MoS2 . Furthermore, Mo/S/PC-10 exhibited better performance in the oxygen reduction reaction (specific activity of 1.23 mA cm-2 at 0.9 V and half-wave potential of 0.864 V) than a commercial Pt catalyst, owing to a heteroatom-doped carbon nanostructure with a fairly high specific surface area. In the polarization curve of the unit-cell performance measured at 80 °C under ambient pressure, Mo/S/PC-10 as a cathode catalyst exhibited an optimal power density of 314 mW cm-2 and a current density of 280 mA cm-2 at 0.6 V.


Assuntos
Carbono/química , Dissulfetos/química , Molibdênio/química , Nanoestruturas/química , Oxigênio/química , Porfirinas/química , Enxofre/química , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Transmissão , Oxirredução , Difração de Raios X
6.
Angew Chem Int Ed Engl ; 56(11): 2893-2897, 2017 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-28157264

RESUMO

In this study, we proposed high-performance chemically regenerative redox fuel cells (CRRFCs) using NO3- /NO with a nitrogen-doped carbon-felt electrode and a chemical regeneration reaction of NO to NO3- via O2 . The electrochemical cell using the nitrate reduction to NO at the cathode on the carbon felt and oxidation of H2 as a fuel at the anode showed a maximal power density of 730 mW cm-2 at 80 °C and twofold higher power density of 512 mW cm-2 at 0.8 V, than the target power density of 250 mW cm-2 at 0.8 V in the H2 /O2 proton exchange membrane fuel cells (PEMFCs). During the operation of the CRRFCs with the chemical regeneration reactor for 30 days, the CRRFCs maintained 60 % of the initial performance with a regeneration efficiency of about 92.9 % and immediately returned to the initial value when supplied with fresh HNO3 .

7.
BMJ Case Rep ; 20152015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-26178005

RESUMO

A 22-year-old man was referred for horizontal diplopia that worsened on left gaze. He had been admitted for a head trauma caused by a traffic accident. Brain CT scan showed a longitudinal fracture of the left temporal bone with extension to the left carotid canal and central skull base, including sphenoid lateral wall and roof, and left orbit medial wall non-displaced fracture. Prism cover test revealed 20 prism diopters of esotropia and abduction limitation in the left eye. Hess screening test results were compatible with left abducens nerve paralysis. Symptoms suggesting complete lower motor neuron palsy of the left facial nerve, such as unilateral facial drooping, inability to raise the eyebrow and difficulty closing the eye, were present. As there was no improvement in facial paralysis, the patient received surgical intervention using a transmastoidal approach. Three months postoperatively, prism cover test showed orthotropia, however, the facial nerve palsy persisted.


Assuntos
Doenças do Nervo Abducente/diagnóstico , Nervo Abducente/patologia , Doenças do Nervo Facial/diagnóstico , Nervo Facial/patologia , Paralisia Facial/diagnóstico , Fraturas Ósseas/complicações , Traumatismos Cranianos Fechados/complicações , Doenças do Nervo Abducente/etiologia , Acidentes de Trânsito , Adulto , Diplopia/diagnóstico , Diplopia/etiologia , Esotropia/diagnóstico , Esotropia/etiologia , Esotropia/cirurgia , Doenças do Nervo Facial/etiologia , Paralisia Facial/etiologia , Humanos , Masculino , Osso Temporal/lesões , Adulto Jovem
8.
J Pharm Biomed Anal ; 102: 162-75, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25282599

RESUMO

The continuing appearance of new synthetic cannabinoids has been a major issue in the field of forensic and clinical toxicology. In response to that, analytical methods for synthetic cannabinoids have been increasingly established in a variety of biological matrices. Since most of synthetic cannabinoids with structure similarity share some enzymatic metabolites, making the interpretation of analytical results and the discovery of the parent drug actually ingested very complicated, the investigation on metabolites of the first generation of synthetic cannabinoids with their relatively short side chains in chemical structure could be more important. Therefore, in the present study, we developed the analytical method for AM-2201, JWH-122 and MAM-2201 with JWH-018 as a precursor and their monohydroxylated metabolites in hair matrix. Also, using a rat model, AM-2201 and its monohydroxylated metabolites were identified and then the ratios of metabolite-to-parent drug were estimated to be used as criteria on external contamination. All analytes were extracted with methanol from washed and cut hair samples and the extracts were injected into LC-MS/MS with electrospray ion source in the positive ionization mode. Matrix effect and recovery were evaluated in hair matrices and no significant variations were observed. The validation results for precision and accuracy were satisfactory in both human and rat hair. The LOD and LOQ were 0.5 pg/10mg and 1.0 pg/10mg in human hair and 0.5 pg/20mg and 1.0 pg/20mg in pigmented and non-pigmented rat hair, respectively. Additionally, as a result of the animal study, there were not significant differences in the effect of pigmentation on the distribution of AM-2201 and its monohydroxylated metabolites in hair. Wide variations were observed for the concentrations of the naphthoylindole-based synthetic cannabinoids and metabolites in authentic hair samples from nine cases; those were 0.4-59.2 pg/mg for JWH-018, 0.1-0.8 pg/mg for JWH-073, 1.7-739.0 pg/mg for AM-2201, 0.1-402.0 pg/mg for JWH-122, 0.2-276.0 pg/mg for MAM-2201, 0.2-1.1 pg/mg for JWH-018 N-COOH, 0.3-37.2 pg/mg for JWH-018 N-5-OH, 0.3 pg/mg for JWH-073 N-COOH, 0.4 pg/mg for AM-2201 N-4-OH, 0.2-3.1 pg/mg for AM-2201 N-6-OHindole and 0.1-3.5 pg/mg for JWH-122 N-5-OH. This quantitative LC-MS/MS analytical method for five naphthoylindole-based synthetic cannabinoids and their metabolites was very useful to be applied to authentic hair samples, of which their analytical results suggested the incorporation of synthetic cannabinoids in the hair matrix and provided the information on ingested parent drugs.


Assuntos
Canabinoides/análise , Cabelo/química , Animais , Cromatografia Líquida , Humanos , Drogas Ilícitas/análise , Indóis/análise , Limite de Detecção , Naftalenos/análise , Ratos , Detecção do Abuso de Substâncias/métodos , Espectrometria de Massas em Tandem
9.
Korean J Spine ; 11(3): 205-8, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25346771

RESUMO

Cysticercosis is the most common parasitic disease affecting the central nervous system. Spinal involvement is rare in neurocysticercosis, and isolated spinal involvement without evidence of cranial involvement is even rarer. We report an unusual case of neurocysticercosis with isolated spinal involvement. A 59 year-old male presented with radiating pain in the left leg. He complained of aggravating weakness and numbness in the left leg since his previous visit one month ago. Magnetic resonance imaging (MRI) revealed multiple peripheral wall-enhanced intradural cystic masses from L1 to L5. The patient underwent a total laminectomy of L4. Dissection revealed abnormal cystic masses compressing the nerve roots. The cyst was punctured, spilling clear mucoid fluid into the surgical field. The exposed cysticerci, white and mucoid, was easily removed. Patient received course of steroids and oral albendazole. The patient experienced symptomatic improvement without further neurologic deficits except for mild sensory impairment. Clinicians should include spinal neurocysticercosis in differential diagnosis of radiculopathies. Although isolated spinal neurocysticercosis is rare, it can be satisfactorily managed with surgery and medication.

10.
Phys Chem Chem Phys ; 16(28): 14644-50, 2014 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-24921219

RESUMO

Since Pt-based catalysts have the disadvantages of high cost, large overpotential loss, and limited long-term stability, there have been various promising alternatives to Pt-based catalysts to improve the catalytic activity towards the oxygen reduction reaction (ORR). We have synthesized iron-nitrogen-doped mesoporous tungsten carbide catalysts (WC-m-FT) by pyrolysis of well-ordered mesoporous tungsten carbides with iron porphyrin. WC-m-FT exhibits excellent ORR catalytic activity in an alkaline medium, i.e. a high electron-transfer number as well as superior stability and methanol tolerance. The improved activity and stability of WC-m-FT are ascribed to iron-containing catalytic active sites surrounded by nitrogen species and the well-defined mesoporous tungsten carbide structure.

11.
Korean J Neurotrauma ; 10(2): 106-11, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27169043

RESUMO

OBJECTIVE: Chronic subdural hematoma (CSDH) is relatively common in neurosurgical field. However not all patients develop CSDH after minor head trauma. In this study, we evaluate the risk factors of post-traumatic CSDH. METHODS: Two-hundred and seventy-seven patients were enrolled and analyzed in this study from January 2012 to December 2013. Of those, 20 participants had minor head trauma developed CSDH afterward. We also included 257 patients with minor head trauma who did not develop CSDH during the same follow-up period as the control group. We investigated the risk factors related to the development of CSDH after minor head trauma. RESULTS: Old age (p=0.014), preexisting diabetes mellitus (p=0.010), hypertension (p=0.026), history of cerebral infarction (p=0.035), antiplatelet agents (p=0.000), acute subdural hematoma in the convexity (p=0.000), encephalomalacia (p=0.029), and long distance between skull and brain parenchyma (p=0.000) were significantly correlated with the development of CSDH after trauma. Multivariate analysis revealed that only the maximum distance between the skull and the cerebral parenchyma was the independent risk factor for the occurrence of CSDH (hazard ratio 2.55, p=0.000). CONCLUSION: We should consider the possibility of developing CSDH in the post-traumatic patients with the identified risk factors.

12.
Am J Ophthalmol ; 156(4): 773-9, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23831219

RESUMO

PURPOSE: To study the clinical outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) with the EndoGlide donor insertion device. DESIGN: Retrospective interventional case series. METHODS: We included 100 eyes that underwent DSAEK for Fuchs endothelial dystrophy or pseudophakic bullous keratopathy (PBK) at a single institution. Eyes with anterior segment pathology or previous intraocular surgery (except for uncomplicated cataract surgery) were excluded. Preoperative data included visual acuity and donor endothelial cell density by specular microscopy. The main outcome measures were postoperative best spectacle-corrected visual acuity (BSCVA) and endothelial cell loss at 3, 6, and 12 months. RESULTS: There were 59 eyes with Fuchs dystrophy and 41 eyes with PBK. In eyes without vision-limiting pathology, the median postoperative BSCVA was consistently 20/40 (range 20/20-20/400) at 3 months (n = 61 eyes), 6 months (n = 55 eyes), and 12 months (n = 48 eyes). Endothelial cell loss was 13.7% at 3 months (n = 57), 13.5% at 6 months (n = 61), and 14.9% at 12 months (n = 53). Primary graft failure occurred in 1 eye, attributable to incorrect use of the insertion device. Two eyes with complete donor dislocation were rebubbled successfully. The most common complication was glaucoma/ocular hypertension in 29 eyes (34.1%) without prior glaucoma and treatment escalation in 6 eyes (40.0%) with prior glaucoma. Of the 78 eyes with 12 months follow-up, 2 (2.6%) developed endothelial rejection, and 1 (1.3%) subsequently failed. CONCLUSIONS: The use of this donor insertion device during DSAEK demonstrates good outcomes and potentially low endothelial cell loss at up to 12 months after surgery.


Assuntos
Distrofias Hereditárias da Córnea/cirurgia , Ceratoplastia Endotelial com Remoção da Lâmina Limitante Posterior/instrumentação , Complicações Intraoperatórias , Complicações Pós-Operatórias , Idoso , Contagem de Células , Distrofias Hereditárias da Córnea/fisiopatologia , Perda de Células Endoteliais da Córnea/diagnóstico , Perda de Células Endoteliais da Córnea/etiologia , Endotélio Corneano/patologia , Feminino , Seguimentos , Humanos , Masculino , Oftalmologia/instrumentação , Estudos Retrospectivos , Doadores de Tecidos , Resultado do Tratamento , Acuidade Visual/fisiologia
13.
ACS Nano ; 7(2): 1573-82, 2013 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-23270373

RESUMO

A synthetic strategy for the fabrication of graphitic carbon nanomaterials containing highly dispersed arrays of metal nanoparticles is reported. This synthetic strategy involves successive deposition of inverse micelle monolayers containing a metal precursor and reduction of the latter, followed by direct carbonization of the obtained multilayer structure of inverse micelles containing metal nanoparticles. Thus, a "direct-carbonization" concept, in which the block copolymer simultaneously serves as soft template and as carbon source, was combined with a multilayer buildup protocol. The inner architecture of the multilayer structures consisting of carbon and metal nanoparticles was studied by X-ray reflectivity, grazing incidence small-angle X-ray scattering, and cross-sectional transmission electron microscopy imaging. The hexagonal near ordering of the metal nanoparticles in the block copolymer micelle multilayers was by and large conserved after carbonization. The resulting carbon structures containing multilayers of highly dispersed metal nanoparticles exhibit superior electrocatalytic activity in formic acid and methanol oxidation, suggesting that they are promising electrode materials for fuel cells.


Assuntos
Grafite/química , Nanopartículas Metálicas/química , Micelas , Catálise , Eletroquímica , Modelos Moleculares , Conformação Molecular , Polímeros/química , Temperatura
15.
Chem Commun (Camb) ; 47(22): 6296-8, 2011 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-21503371

RESUMO

We report Pt nanocubes of ∼4.5 nm in size synthesized by thermal decomposition in the presence of PVP. The Pt cubic electrocatalysts with dominantly exposed {100} facets show much improved electrocatalytic activities in methanol, ethanol and formic acid electrooxidation.

16.
Phys Chem Chem Phys ; 13(13): 5569-72, 2011 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-21327266

RESUMO

We report Pt-Pd nanoparticles synthesized by means of a polyol process with glycerol as a reducing agent. The Pt-Pd nanoparticles exhibit dominantly exposed {111} facets in octahedral shape with complete alloy formation between Pt and Pd. Furthermore, the octahedral Pt-Pd alloy catalysts show improved catalytic activity and stability in methanol electrooxidation.

17.
Chem Commun (Camb) ; 47(12): 3496-8, 2011 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-21308125

RESUMO

The H(2)-NO(3)(-) electrochemical cell using nitrate reduction on a non-precious cathode catalyst shows much improved efficiency despite ∼75% reduction of Pt metal loading as compared to typical PEMFCs using typical ORR on precious catalysts.

18.
Bioresour Technol ; 102(1): 342-7, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20656480

RESUMO

Co-naphthalocyanine (CoNPc) was prepared by heat treatment for cathode catalysts to be used in microbial fuel cells (MFCs). Four different catalysts (Carbon black, NPc/C, CoNPc/C, Pt/C) were compared and characterized using XPS, EDAX and TEM. The electrochemical characteristics of oxygen reduction reaction (ORR) were compared by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The Co-macrocyclic complex improves the catalyst dispersion and oxygen reduction reaction of CoNPc/C. The maximum power of CoNPc/C was 64.7 mW/m(2) at 0.25 mA as compared with 81.3 mW/m(2) of Pt/C, 29.7 mW/m(2) of NPc/C and 9.3 mW/m(2) of carbon black when the cathodes were implemented in H-type MFCs. The steady state cell, cathode and anode potential of MFC with using CoNPc/C were comparable to those of Pt/C.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Cobalto/química , Complexos de Coordenação/química , Naftalenos/química , Compostos Organometálicos/química , Catálise , Eletricidade , Eletroquímica , Eletrodos , Microanálise por Sonda Eletrônica/métodos , Microscopia Eletrônica de Transmissão/métodos , Oxirredução , Espectrometria por Raios X/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos
19.
Chem Commun (Camb) ; 46(48): 9241-3, 2010 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-21046032

RESUMO

We report cuboctahedral Pd nanoparticles on WC synthesized by the polyol process using ethylene glycol with NO(3)(-) and Fe(3+)/Fe(2+) ions. The cuboctahedral Pd/WC shows much improved electrocatalytic activity for methanol electrooxidation in alkaline solution.

20.
Phys Chem Chem Phys ; 12(46): 15181-3, 2010 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-20820565

RESUMO

We report nanostructure electrodes for methanol electrooxidation by means of the co-sputtering deposition method. The Pt-WC-WO(3) three-phase electrode has higher I(f)/I(b) and oxidation current density i.e. improved electrocatalytic activity in comparison with those of pure Pt and two-phase electrodes because of both catalysis of tungsten carbide and size-control by tungsten oxide.

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