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1.
Environ Monit Assess ; 194(7): 469, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35648296

RESUMO

Water quality of the Ganga River system is changing day by day due to multifold increase in population, especially near the banks of river Ganga, and associated exponential amplification of anthropogenic activities also played a remarkable role in it. The ecologically important lower and estuarine stretch of river Ganga comprising 7 different sampling stations, i.e., Jangipur, Berhampore, Balagarh, Tribeni, Godakhali, Diamond Harbour and Fraserganj, were selected for the study as the stretch is enriched with the vast number of floral and faunal diversity. The study was conducted for a period of 5 years, i.e., from 2016 to 2020. In the study, various analytical tools and techniques were used for the assessment of riverine water quality, i.e., for calculation of water quality index (WQI); The National Sanitation Foundation Water Quality Index (NSF-WQI) and the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI) were used for the assessment. Along with WQI various statistical univariate as well as multivariate analytical tools like principal component analysis, correlation, ANOVA, and cluster analysis were also used to achieve the desired outputs. In the study, it has been observed that NSF-WQI varied from 61 to 2552, in which the higher value of NSF-WQI denoted the unsuitability of the water quality concerning the drinking water standards and vice versa. The CCME-WQI represented a similar trend as that of NSF-WQI, as it varied from 18 to 92 in which the lower value denoted degradation in the drinking water quality and vice versa. The study revealed that the Diamond Harbour-Fraserganj stretch is having an undesired level of water quality which were analyzed based on the drinking water guideline values of the Bureau of Indian Standards and that of NSF-WQI and CCME-WQI.


Assuntos
Água Potável , Qualidade da Água , Canadá , Diamante , Monitoramento Ambiental/métodos , Rios
2.
J Mech Behav Biomed Mater ; 132: 105278, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35653917

RESUMO

The aim of this study was to evaluate the topography and the fatigue performance of lithium disilicate glass-ceramic after surface grinding through different laboratory protocols used to simulate the Computer-aided design/Computer-aided manufacturing (CAD/CAM) milling. Ceramic discs (IPS e.max CAD, Ø = 13.5 mm × 1.2 mm of thickness) were produced through different methodologies: milling in CAD/CAM system (CAD/CAM group); produced in-lab with a polished surface (POL group); or produced through in-lab methods and randomly distributed into five groups according to different grinding protocols to simulate the CAD/CAM milling [grinding with a CAD/CAM bur coupled to a mandrel (CAD/CAM Bur group); fine diamond bur using oscillatory movements (DBO group); fine diamond bur in x and y axes of the disc (DBXY group); #60-grit silicon carbide sandpaper (SiC group); and #60-grit wood sandpaper (WS group)]. The specimens were fatigue tested (n = 15) according to the step-stress method (initial load: 60 N; step-size: 20 N; 10,000 cycles/step; 20 Hz frequency). A roughness analysis was performed on all specimens, while fractal dimension (FD) and fractography were performed on representative samples. The Kaplan-Meier analysis showed that the POL (293.3 N) group presented better fatigue performance (higher load and number of cycles for failure) (p < 0.05) than the other groups (CAD/CAM = 222.7 N; CAD/CAM Bur = 181.3 N; DBO = 184.0 N; DBXY = 192.0 N; SiC = 182.6 N; WS = 182.6 N). For roughness, only the SiC (Ra = 1.616; Rz = 10.465) and WS (Ra = 1.673; Rz = 10.655) groups produced statistically similar Ra (µm) and Rz (µm) values to the CAD/CAM (Ra = 1.628; Rz = 9.571) group (p > 0.05). The surface created by CAD/CAM milling and POL group exhibited more complexity (FD) higher values than the experimental groups. For the ceramic surface topography images, the CAD/CAM milling visibly produced a uniform surface compared to the other groups; however, the POL group was the smoothest. The DBO, DBXY, SiC, and WS groups resulted in similar characteristics of surface topography. Therefore, although the SiC and WS groups showed similar roughness to the control group (CAD/CAM), no in-lab simulation method was fully capable to mimic the mechanical performance of the CAD/CAM-milled lithium disilicate glass-ceramic.


Assuntos
Cerâmica , Desenho Assistido por Computador , Porcelana Dentária , Diamante , Teste de Materiais , Propriedades de Superfície
3.
Analyst ; 147(11): 2523-2532, 2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35543208

RESUMO

We report herein on the use of a boron-doped diamond microelectrode (DME) to record oxidation currents in vitro associated with the release of serotonin from enterochromaffin cells in the epithelium of the human intestinal mucosa. Continuous amperometric measurements were made as a function of distance (ln current vs. distance) from the tissue surface in human jejunum specimens. The results demonstrate the capabilities of the DME for the stable and reproducible detection of serotonin in the complex environment of the human tissue. Serotonin release was evoked by the shearing force of a continuously flowing Krebs buffer solution at 36 °C with the tissue pinned down in a flow bath. Reproducible currents with distance were recorded for serotonin oxidation. Increased oxidation currents were observed in the presence of the selective serotonin reuptake inhibitor, fluoxetine, indicating that a significant fraction of the amperometric current recorded is attributable to serotonin oxidation. The nominal reciprocal slope, |slope-1|, of the ln current vs. distance plots increased from 270 ± 25 µm-1 in Krebs buffer (N = 3) to 471 ± 65 µm-1 during fluoxetine addition (N = 3), reflective of a reduced rate of reuptake in the presence of the SERT antagonist. The paper reports on the characterization of the diamond microelectrodes and the in vitro electrochemical measurement data.


Assuntos
Diamante , Serotonina , Fluoxetina/farmacologia , Humanos , Mucosa Intestinal , Jejuno , Microeletrodos
4.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 47(2): 226-237, 2022 Feb 28.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-35545413

RESUMO

OBJECTIVES: Root canal therapy is the most effective and common method for pulpitis and periapical periodontitis. During the root canal preparation, chemical irrigation plays a key role. However, sodium hypochlorite (NaOCl), the widely used irrigation fluid, may impact the bonding strength between dentin and restorative material meanwhile sterilization and dissolving. Therefore, it's important to explore the influence of NaOCl on the adhesion between dentin and restoration materials to ensure clinical efficacy. This study aims to explore the effect of NaOCl on dentine adhesion and evaluate the effect of dentine adhesion induced by sodium erythorbate (ERY), and to provide clinical guidance on dentin bonding after root canal therapy. METHODS: Seventy freshly complete extracted human third molars aged 18-33 years old, without caries and restorations were selected. A diamond saw was used under running water to achieve dentine fragments which were divided into 10 groups with 14 fragments in each group: 2 control [deionized water (DW)±10% ERY] and 8 experimental groups (0.5%, 1%, 2.5%, and 5.25% NaOCl±10% ERY). The dentine specimens in the control group (treated with DW) and the experimental groups (treated with 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl) were immersed for 20 min using corresponding solutions which were renewed every 5 min. The other 5 groups were immersed in 10% ERY for 5 min after an initial washing with DW for 1 min. Then, we selected 4 dentine fragments from all 14 fragments in each group and the numbers and diameters of opening dentinal tubules were observed under scanning electron microscope (SEM). The other 10 dentine fragments from each group were used to make adhesive samples by using self-etch adhesive wand composite resin. All the above adhesive samples were sectioned perpendicular to the bonded interface into 20 slabs with a cross-sectional area of 1 mm×1 mm using a diamond saw under the cooling water, and then the morphology of 10 slabs in each group's bonding interface was observed from aspects of formation of resin tags, depth of tags in dentin, and formation of hybrid layer under SEM. The other 10 slabs of each group's microtensile bond strength and failure modes were also analyzed. RESULTS: Among the 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl groups, the number and diameter of patent dentinal tubules gradually increased with the rise of concentration of NaOCl solution (all P<0.05). Among the DW, 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl groups, the number and diameter of patent dentinal tubules increased after using ERY, but without significant difference (all P>0.05). Among the DW, 0.5% NaOCl, 1% NaOCl, and 2.5% NaOCl groups, the scores of formation of resin tags under SEM gradually increased with the increase of concentration of NaOCl solution, while the score in the 5.25% NaOCl group decreased significantly compared with the score of the 2.5% NaOCl group (P<0.05). There was no significant difference between using 10% ERY groups and without using 10% ERY groups (all P>0.05). The scores of length of the tags under SEM in the 5.25% NaOCl group was significantly higher than the scores of DW, 0.5% NaOCl, and 1% NaOCl groups (all P<0.05), and it was also higher than the score of the 2.5% NaOCl group, but without significant difference (P>0.05). There was no significant difference between using 10% ERY groups and without using 10% ERY groups (P>0.05). The scores of formation of hybrid layer under SEM in the 2.5% NaOCl and 5.25% NaOCl groups significantly decreased compared with the score of the DW group (all P<0.05). There were significant differences between the 2.5% NaOCl±10% ERY groups and between the 5.25% NaOCl±10% ERY groups (all P<0.05). Microtensile bond strength was greater in the 0.5% NaOCl, 1% NaOCl, and 2.5% NaOCl groups, but lower in the 5.25% NaOCl group than that in the DW group (all P<0.05). There were significant differences between the 2.5% NaOCl±10% ERY groups and between the 5.25% NaOCl±10% ERY groups (all P<0.05). The incidence of type "Adhesive" of failure modes in the 5.25% NaOCl group was significantly higher than that in other groups (all P<0.05), while the incidence of type "Adhesive" in the 5.25% NaOCl+10% ERY group was lower than that in the 5.25% NaOCl group (P<0.05). CONCLUSIONS: The bonding strength to dentine increases with the increase of NaOCl concentration when the concentration lower than 2.5%; whereas it is decreased at a higher concentration (such as 5.25%). 10% ERY has a definite recovery effect on attenuated bonding strength to 5.25% NaOCl-treated dentine.


Assuntos
Colagem Dentária , Hipoclorito de Sódio , Adolescente , Adulto , Ácido Ascórbico , Dentina , Adesivos Dentinários/química , Adesivos Dentinários/farmacologia , Diamante/farmacologia , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Cimentos de Resina/química , Cimentos de Resina/farmacologia , Hipoclorito de Sódio/química , Hipoclorito de Sódio/farmacologia , Resistência à Tração , Água/farmacologia , Adulto Jovem
5.
Phys Chem Chem Phys ; 24(19): 11696-11703, 2022 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-35506456

RESUMO

The modification of nitrogen-contaminated diamonds into color-enhanced diamonds is usually achieved by irradiation and thermal treatment (annealing). These treatments affect nitrogen contamination chemical bonding, vacancy concentration, and atom orientation centers in the diamond lattice. In this study, natural diamonds were subjected to irradiation and thermal annealing color enhancement treatments to produce green, blue, and yellow fancy diamonds. The study followed the changes that occur during treatment relying on visual assessment, fluorescence, UV-vis, FTIR, and EPR spectroscopy to characterize paramagnetic centers. The results indicated that diamonds containing high levels of nitrogen contamination presented a relatively high carbon-centered radical concentration. Two paramagnetic groups with different g-values were found, namely, low g-value centers of 2.0017-2.0027 and high g-value centers of 2.0028-2.0035. It is suggested that the 2.0017-2.0022 centers correlate with blue centers, whereas the 2.0023-2.0027 centers correlate with yellow centers. It was also found that thermal treatment was required to produce blue and yellow fancy diamonds, whereas no such treatment was needed to produce green diamonds.


Assuntos
Carbono , Diamante , Diamante/química , Espectroscopia de Ressonância de Spin Eletrônica , Nitrogênio/química
6.
Health Phys ; 122(6): 685-695, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35383629

RESUMO

ABSTRACT: Ultra-short, ultra-intense laser facilities could produce ultra-intense pulsed radiation fields. Currently, only passive detectors are fit for dose measurement in this circumstance. Since the laser device could generate a dose up to tens of mSv outside the chamber in tens of picoseconds, resulting in a high instantaneous dose rate of ~107 Sv s-1, it is necessary to perform real-time dose measurement to ensure the safety of nearby workers. Due to fast response and excellent radiation resistance, a diamond-based dose measurement device was designed and developed, and its dose-rate response and its feasibility for such occasions were characterized. The measurement results showed that the detector had a good dose-rate linearity in the range of 3.39 mGy h-1 to 10.58 Gy h-1 for an x-ray source with energy of 39 keV to 208 keV. No saturation phenomenon was observed, and the experimental results were consistent with the results obtained from Monte Carlo simulation. The charge collection efficiency was about 80%. Experimental measurements and simulations with this dose measurement device were carried out based on the "SG-II" laser device. The experimental and simulation results preliminarily verified the feasibility of using the diamond detector to measure the dose generated by ultra-short, ultra-intense laser devices. The results provided valuable information for the follow-up real-time dose measurement work of ultra-short, ultra-intense laser devices.


Assuntos
Diamante , Radiometria , Humanos , Lasers , Método de Monte Carlo , Radiometria/métodos , Raios X
7.
Pancreatology ; 22(4): 534-538, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35443912

RESUMO

BACKGROUND: Family history of pancreatic cancer (PC) and some hereditary cancer syndromes are risk factors for PC. Previous studies suggest that conducting surveillance for kindreds at high risk for familial PC may be useful for diagnoses at the stage where resections can still be implemented; however, there is insufficient evidence linking surveillance and increased rates of resectable PC. METHODS: We launched a surveillance study for kindreds with familial PC and individuals with hereditary PC syndrome, titled the "Diamond Study," in June 2020. This Japanese national multi-institutional prospective intervention study has been initiated to conduct evaluations within a prospective clinical trial format. RESULTS: The primary endpoint is the fraction of patients with resectable PC among patients with PC found through surveillance interventions. Endoscopic ultrasound and magnetic resonance imaging combined with magnetic resonance cholangiopancreatography will be performed alternatively every 6 months for up to 15 years, with 400 as the predicted number of registered participants and a predicted registration period of 10 years. CONCLUSION: We intend to scientifically prove the usefulness of surveillance for kindreds with familial PC and individuals with hereditary PC syndrome to improve PC prognoses.


Assuntos
Síndromes Neoplásicas Hereditárias , Neoplasias Pancreáticas , Carcinoma , Diamante , Predisposição Genética para Doença , Humanos , Estudos Multicêntricos como Assunto , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/epidemiologia , Neoplasias Pancreáticas/genética , Estudos Prospectivos
8.
Int J Mol Sci ; 23(7)2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35409191

RESUMO

The hydrothermal approach has been used to fabricate a heterojunction of n-aluminum-doped ZnO nanorods/p-B-doped diamond (n-Al:ZnO NRs/p-BDD). It exhibits a significant increase in photoluminescence (PL) intensity and a blue shift of the UV emission peak when compared to the n-ZnO NRs/p-BDD heterojunction. The current voltage (I-V) characteristics exhibit excellent rectifying behavior with a high rectification ratio of 838 at 5 V. The n-Al:ZnO NRs/p-BDD heterojunction shows a minimum turn-on voltage (0.27 V) and reverse leakage current (0.077 µA). The forward current of the n-Al:ZnO NRs/p-BDD heterojunction is more than 1300 times than that of the n-ZnO NRs/p-BDD heterojunction at 5 V. The ideality factor and the barrier height of the Al-doped device were found to decrease. The electrical transport behavior and carrier injection process of the n-Al:ZnO NRs/p-BDD heterojunction were analyzed through the equilibrium energy band diagrams and semiconductor theoretical models.


Assuntos
Nanotubos , Óxido de Zinco , Diamante , Semicondutores
9.
Biosens Bioelectron ; 209: 114222, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35430407

RESUMO

The 21st century has already brought us a plethora of new threats related to viruses that emerge in humans after zoonotic transmission or drastically change their geographic distribution or prevalence. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first spotted at the end of 2019 to rapidly spread in southwest Asia and later cause a global pandemic, which paralyzes the world since then. We have designed novel immunosensors targeting conserved protein sequences of the N protein of SARS-CoV-2 based on lab-produced and purified anti-SARS-CoV-2 nucleocapsid antibodies that are densely grafted onto various surfaces (diamond/gold/glassy carbon). Titration of antibodies shows very strong reactions up to 1:72 900 dilution. Next, we showed the mechanism of interactions of our immunoassay with nucleocapsid N protein revealing molecular recognition by impedimetric measurements supported by hybrid modeling results with both density functional theory and molecular dynamics methods. Biosensors allowed for a fast (in less than 10 min) detection of SARS-CoV-2 virus with a limit of detection from 0.227 ng/ml through 0.334 ng/ml to 0.362 ng/ml for glassy carbon, boron-doped diamond, and gold surfaces, respectively. For all tested surfaces, we obtained a wide linear range of concentrations from 4.4 ng/ml to 4.4 pg/ml. Furthermore, our sensor leads to a highly specific response to SARS-CoV-2 clinical samples versus other upper respiratory tract viruses such as influenza, respiratory syncytial virus, or Epstein-Barr virus. All clinical samples were tested simultaneously on biosensors and real-time polymerase chain reactions.


Assuntos
Técnicas Biossensoriais , COVID-19 , Infecções por Vírus Epstein-Barr , Anticorpos Antivirais , Técnicas Biossensoriais/métodos , Boro , COVID-19/diagnóstico , Carbono , Diamante , Ouro , Herpesvirus Humano 4 , Humanos , Imunoensaio/métodos , Nucleocapsídeo , Proteínas do Nucleocapsídeo , SARS-CoV-2
10.
Small ; 18(20): e2200592, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35426236

RESUMO

The brilliant appearance of Easter Egg weevils, genus Pachyrhynchus (Coleoptera, Curculionidae), originates from complex dielectric nanostructures within their elytral scales and elytra. Previous work, investigating singular members of the Pachyrhynchus showed the presence of either quasi-ordered or ordered 3D photonic crystals based on the single diamond ( F d 3 ¯ m ) symmetry in their scales. However, little is known about the diversity of the structural coloration mechanisms within the family. Here, the optical properties within Pachyrhynchus are investigated by systematically identifying their spectral and structural characteristics. Four principal traits that vary their appearance are identified and the evolutionary history of these traits to identify ecological trends are reconstructed. The results indicate that the coloration mechanisms across the Easter Egg weevils are diverse and highly plastic across closely related species with features appearing at multiple independent times across their phylogeny. This work lays a foundation for a better understanding of the various forms of quasi-ordered and ordered diamond photonic crystal within arthropods.


Assuntos
Besouros , Nanoestruturas , Gorgulhos , Animais , Besouros/química , Diamante , Nanoestruturas/química , Fótons
11.
Anal Chem ; 94(16): 6403-6409, 2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35427116

RESUMO

A new method for the determination of skatole present in porcine adipose tissue samples utilizing the electrochemiluminescence of skatole is presented. It has been observed that oxygen radicals produced at a high cathodic voltage can react with oxidized skatole to create an excited intermediate molecule that then relaxes, generating peak photon emission at around 480 nm. A strong electrochemiluminescence or electrogenerated chemiluminescence (ECL) signal using boron-doped diamond (BDD) electrodes was observed optimally when a reduction potential of -1.8 V was applied, held for 40 s, before holding an oxidation potential of 0.8 V for 10 s. Using this principle, a calibration curve using known concentrations of skatole showed good linearity (range 0.025-2 µM) and a very low detection limit (LOD, 0.7 nM). A method that demonstrates for the first time an approach that utilizes this ECL reaction, and has the potential to be developed into an analytical device for use in the slaughterhouse, has been developed. This was achieved by extracting skatole out of the porcine adipose tissues into acetonitrile - giving an extraction efficiency of 67.6%. This method was then validated by analyzing the skatole content of 33 pig fat samples that had been previously tested using a standard technique, high-performance liquid chromatography (HPLC), containing a range of concentrations (0.02-2.58 µg/g). This ECL method exhibited excellent reliability and correlation with HPLC, giving a R2 coefficient of 0.911, thus demonstrating the potential for this method to be developed for an on-line skatole detector.


Assuntos
Diamante , Escatol , Tecido Adiposo/química , Animais , Eletrodos , Reprodutibilidade dos Testes , Escatol/análise , Suínos
12.
J Mech Behav Biomed Mater ; 131: 105224, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35413493

RESUMO

Soft machining is a key procedure in fabrication of high-strength lithium-based silicate glass ceramic (LS) restorations. This paper reports on the diamond machining-induced surface and edge chipping damage in two pre-crystalized LS materials: pre-crystallized lithium metasilicate/orthophosphate glass ceramic (Pre-LS, IPS e.max CAD) and pre-crystallized zirconia-containing lithium metasilicate glass ceramic (Pre-ZLS, Vita Suprinity). Indentation techniques were used to measure the material mechanical properties. Soft machining was conducted using a robotic controlled apparatus mimicking dental CAD/CAM machining processes at different removal rates and enabling in-process force measurement. Machined surface roughness was assessed using 3D confocal optical profilometry in terms of the average and maximum surface heights. Scanning electron microscopy was used to assess diamond tool and machined surface and edge morphology. Soft machining of both materials was dominated by brittle fracture mixed with localized ductile flow. However, the higher brittleness index of Pre-ZLS than Pre-LS yielded higher degrees of machining-induced conchoidal fractures in Pre-ZLS in comparison with irregular fractures in Pre-LS. Thus, much larger surface roughness and deeper edge chipping damage were produced in Pre-ZLS than Pre-LS. Machining forces for Pre-ZLS were significantly smaller than Pre-LS, due to the lower machinability index associated with a complex relation of the mechanical properties as well as less debris adhesion for Pre-ZLS than Pre-LS. Further, increased material removal rates resulted in significantly increased machining forces, maximum surface roughness and fracture, and edge chipping damage in both Pre-ZLS and Pre-LS materials. Therefore, optimization of soft machining processes needs to be practiced to achieve accepted surface and edge quality at balanced removal rates.


Assuntos
Cerâmica , Lítio , Desenho Assistido por Computador , Porcelana Dentária , Diamante , Teste de Materiais , Silicatos , Propriedades de Superfície , Zircônio
13.
Sensors (Basel) ; 22(5)2022 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-35270954

RESUMO

Diamond has many appealing properties, including biocompatibility, ease of surface modification, and chemical-physical stability. In this study, the temperature dependence of the pH-sensitivity of a oxygen-terminated boron-doped diamond solution gate FET (C-O BDD SGFET) is reported. The C-O BDD SGFET operated in an electrolyte solution at 95 °C. At 80 °C, the pH sensitivity of C-O BDD SGFET dropped to 4.27 mV/pH. As a result, we succeeded in developing a highly sensitive pH sensing system at -54.6 mV/pH at 80 °C by combining it with a highly pH sensitive stainless-steel vessel.


Assuntos
Diamante , Oxigênio , Boro/química , Diamante/química , Concentração de Íons de Hidrogênio , Temperatura
14.
Environ Res ; 211: 113057, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35271837

RESUMO

Electrochemical oxidation is an effective technique for treating persistent organic pollutants, which are hardly removed in conventional wastewater treatment plants. Sulfate and chloride salts commonly used and present in natural wastewater influence the electrochemical degradation process. In this study, the effect of electrolyte composition on the active sulfate species (SO4●⁻ and S2O82⁻) formation, benzotriazole degradation-a model organic compound, and chlorinated by-products distribution have been investigated while using a boron-doped diamond (BDD) anode. Different Na2SO4:NaNO3 and Na2SO4:NaCl ratios with constant conductivity of 10 mS/cm were used in the experiments and applied anode potential was kept constant at 4.3 V vs. Ag/AgCl. The electrogenerated SO4●⁻ and S2O82⁻ formation were faster in 10:1 and 2:1 Na2SO4:NaNO3 ratios than in the 1:0 ratio. The ●OH-mediated SO4●⁻ production has prevailed in 10:1 and 2:1 ratios. However, ●OH-mediated SO4●⁻ production has hindered the 1:0 ratio due to excess chemisorption of SO42⁻ on the BDD anode. Similarly, the faster benzotriazole degradation, mineralization, and lowest energy consumption were achieved in the 10:1 Na2SO4:NaNO3 and Na2SO4:NaCl ratio. Besides, chlorinated organic by-product concentration (AOX) was lower in the 10:1 Na2SO4:NaCl ratio but increased with the increasing chloride ratio in the electrolyte. LC-MS analysis shows that several chlorinated organic transformation products were produced in 0:1 to 2:1 ratio, which was not found in the 10:1 Na2SO4:NaCl ratio. A comparatively higher amount of ClO4⁻ was formed in the 10:1 ratio than in 2:1 to 0:1 ratio. This ClO4⁻ formation train evidence the effective ●OH generation in a sulfate-enriched condition because the ClO4⁻ formation is positively correlated to ●OH concentration. Overall results show that sulfate-enriched electrolyte compositions are beneficial for electrochemical oxidation of biorecalcitrant organic pollutants.


Assuntos
Sulfatos , Poluentes Químicos da Água , Boro , Cloretos , Diamante , Eletrólitos/química , Oxirredução , Cloreto de Sódio , Sulfatos/química , Triazóis , Poluentes Químicos da Água/química
15.
Sci Total Environ ; 830: 154825, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35341842

RESUMO

Using boron-doped diamond (BDD) anodes to degrade bisphenol A (BPA) had been an active area of research interest within the past 20 years. A major concern about the process lie in the formation of toxic chlorinated aromatic by-products when chloride electrolytes were present in the reaction system. In this contribution, we highlighted the formation of complex poly-chlorinated oligomer by-products in electrochemical oxidation processes, which had often been overlooked in previous studies. Moreover, the distribution and complexity of the chlorinated oligomers were found to be strongly linked to the adopted initial chloride concentration. Formation of simple chlorinated by-products was ascribed to the electrophilic substitution reactions mediated by active chlorine species, while the oligomer by-products (including chlorinated dimers, trimers and tetramers) were generated through the coupling reactions between various chlorinated phenoxy radicals. The possible mechanisms describing the formation of these by-products were also proposed. The obtained results shed light on the possible risk of BDD technology in the treatment of phenolic wastewater containing chloride electrolytes.


Assuntos
Cloretos , Poluentes Químicos da Água , Compostos Benzidrílicos , Boro , Diamante , Técnicas Eletroquímicas , Eletrodos , Oxirredução , Fenóis
16.
Med Phys ; 49(6): 4056-4070, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35315526

RESUMO

PURPOSE: Silicon diodes are often the detector of choice for relative dose measurements, particularly in the context of radiotherapy involving small photon beams. However, a major drawback lies in their dose-rate dependency. Although ionization chambers are often too large for small field output factor (OF) measurements, they are valuable instruments to provide reliable percent-depth dose (PDD) curves in reference beams. The aim of this work is to propose a practical and accurate method for the characterization of silicon diode dose-rate dependence correction factors using ionization chamber measurements as a reference. METHODS: The robustness of ionization chambers for PDD measurements is used to quantify the dose-rate dependency of a diode detector. A mathematical formalism, which exploits the error induced in percent-depth ionization (PDI) curves for diodes by their dose-rate dependency, is developed to derive a dose-rate correction factor applicable to diode relative measurements. The method is based on the definition of the recombination correction factor given in the addendum to TG 51 and is applied to experimental measurements performed on a CyberKnife M6 radiotherapy unit using a PTW 60012 diode detector. A measurement-based validation is provided by comparing corrected PDI curves to measurements performed with a PTW 60019 diamond detector, which does not exhibit dose-rate dependence. RESULTS: Results of dose-rate correction factors for PDI curves, off-axis ratios (OARs), tissue-phantom ratios, and small field OFs are coherent with the expected behavior of silicon diode detectors. For all considered setups and field sizes, the maximum correction and the maximum impact of the uncertainties induced by the correction are obtained for OARs for the 60 mm collimator, with a correction of 2.5% and an uncertainty of 0.34%. For OFs, corrections range from 0.33% to 0.82% for all field sizes considered, and increase with the reduction of the field size. Comparison of PDI curves corrected for dose-rate and for in-depth beam quality variations illustrates excellent agreement with measurements performed using the diamond detector. CONCLUSION: The proposed method allows the efficient and precise correction of the dose-rate dependence of silicon diode detectors in the context of clinical relative dosimetry.


Assuntos
Radiometria , Silício , Diamante , Imagens de Fantasmas , Radiometria/métodos , Dosagem Radioterapêutica , Silício/química , Silício/uso terapêutico , Incerteza
17.
Dermatol Ther ; 35(6): e15459, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35304935

RESUMO

To investigate the efficacy and safety of combined treatment with a serum comprising a micro-diamond suspension and micro-gold cage with a 1064 nm picosecond neodymium-doped yttrium aluminum garnet (Nd:YAG) laser for facial skin rejuvenation. Topical serum was applied to the entire face and allowed to penetrate the skin and hair follicles for 20 min. Each participant was then treated with a 1064 nm picosecond Nd:YAG laser on the face. Photographs of each participant were taken at baseline, immediately after treatment, and 2 weeks after treatment using an imaging tool (Mark-Vu®; PSI PLUS, Suwon, Republic of Korea). Global improvement scores by two blinded investigators and participants' satisfaction scores were also assessed. The melanin index (MI), transepidermal water loss (TEWL), and skin hydration were evaluated using a device. Parameters associated with skin rejuvenation were assessed using Mark-Vu®. Adverse events were observed and reported by participants and physicians during the treatment and follow-up visit. At week 2, 40% (4/10) of the participants showed more than moderate clinical improvement in the investigator's global improvement assessment. No significant differences were observed in the MI, TEWL, skin hydration level, or skin parameters of Mark-Vu®. At week 2, 40% of the participants reported a high satisfaction score and minimal side effects. The novel topical facial serum comprising micro-diamond suspension and micro-gold cage is safe and effective when combined with laser treatment for facial rejuvenation.


Assuntos
Lasers de Estado Sólido , Envelhecimento da Pele , Diamante , Ouro , Humanos , Lasers de Estado Sólido/efeitos adversos , Projetos Piloto , Rejuvenescimento , Resultado do Tratamento
18.
J Am Chem Soc ; 144(11): 4897-4912, 2022 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-35261249

RESUMO

O2 oxidation and sublimation kinetics for >30 individual nanoparticles (NPs) of five different feedstocks (graphite, graphene oxide, carbon black, diamond, and nano-onion) were measured using single-NP mass spectrometry at temperatures (TNP) in the 1100-2900 K range. It was found that oxidation, studied in the 1200-1600 K range, is highly sensitive to the NP surface structure, with etching efficiencies (EEO2) varying by up to 4 orders of magnitude, whereas sublimation rates, significant only for TNP ≥ ∼1700 K, varied by only a factor of ∼3. Its sensitivity to the NP surface structure makes O2 etching a good real-time structure probe, which was used to follow the evolution of the NP surface structures over time as they were either etched or annealed at high TNP. All types of carbon NPs were found to have initial EEO2 values in the range near 10-3 Da/O2 collision, and all eventually evolved to become essentially inert to O2 (EEO2 < 10-6 Da/O2 collision); however, the dependence of EEO2 on time and mass loss was very different for NPs from different feedstocks. For example, diamond NPs evolved rapidly and monotonically toward inertness, and evolution occurred in both oxidizing and inert atmospheres. In contrast, graphite NPs evolved only under oxidizing conditions and were etched with complex time dependence, with multiple waves of fast but non-monotonic etching separated by periods of near-inertness. Possible mechanisms to account for the complex etching behavior are proposed.


Assuntos
Grafite , Nanopartículas , Diamante , Grafite/química , Cinética , Nanopartículas/química , Oxirredução , Temperatura
19.
Am J Physiol Heart Circ Physiol ; 322(6): H936-H952, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35302879

RESUMO

Cardiac fiber direction is an important factor determining the propagation of electrical activity, as well as the development of mechanical force. In this article, we imaged the ventricles of several species with special attention to the intraventricular septum to determine the functional consequences of septal fiber organization. First, we identified a dual-layer organization of the fiber orientation in the intraventricular septum of ex vivo sheep hearts using diffusion tensor imaging at high field MRI. To expand the scope of the results, we investigated the presence of a similar fiber organization in five mammalian species (rat, canine, pig, sheep, and human) and highlighted the continuity of the layer with the moderator band in large mammalian species. We implemented the measured septal fiber fields in three-dimensional electromechanical computer models to assess the impact of the fiber orientation. The downward fibers produced a diamond activation pattern superficially in the right ventricle. Electromechanically, there was very little change in pressure volume loops although the stress distribution was altered. In conclusion, we clarified that the right ventricular septum has a downwardly directed superficial layer in larger mammalian species, which can have modest effects on stress distribution.NEW & NOTEWORTHY A dual-layer organization of the fiber orientation in the intraventricular septum was identified in ex vivo hearts of large mammals. The RV septum has a downwardly directed superficial layer that is continuous with the moderator band. Electrically, it produced a diamond activation pattern. Electromechanically, little change in pressure volume loops were noticed but stress distribution was altered. Fiber distribution derived from diffusion tensor imaging should be considered for an accurate strain and stress analysis.


Assuntos
Imagem de Tensor de Difusão , Septo Interventricular , Animais , Diamante , Cães , Ventrículos do Coração , Mamíferos , Miocárdio , Ratos , Ovinos , Suínos , Septo Interventricular/diagnóstico por imagem
20.
Nat Commun ; 13(1): 1260, 2022 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-35273190

RESUMO

Nuclear magnetic resonance imaging (MRI) at the atomic scale offers exciting prospects for determining the structure and function of individual molecules and proteins. Quantum defects in diamond have recently emerged as a promising platform towards reaching this goal, and allowed for the detection and localization of single nuclear spins under ambient conditions. Here, we present an efficient strategy for extending imaging to large nuclear spin clusters, fulfilling an important requirement towards a single-molecule MRI technique. Our method combines the concepts of weak quantum measurements, phase encoding and simulated annealing to detect three-dimensional positions from many nuclei in parallel. Detection is spatially selective, allowing us to probe nuclei at a chosen target radius while avoiding interference from strongly-coupled proximal nuclei. We demonstrate our strategy by imaging clusters containing more than 20 carbon-13 nuclear spins within a radius of 2.4 nm from single, near-surface nitrogen-vacancy centers at room temperature. The radius extrapolates to 5-6 nm for 1H. Beside taking an important step in nanoscale MRI, our experiment also provides an efficient tool for the characterization of large nuclear spin registers in the context of quantum simulators and quantum network nodes.


Assuntos
Diamante , Imageamento por Ressonância Magnética , Diamante/química , Imageamento por Ressonância Magnética/métodos , Nanotecnologia , Nitrogênio/química , Proteínas
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