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1.
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
2.
Health Phys ; 122(6): 685-695, 2022 Jun 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
3.
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
4.
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
5.
Anal Chem ; 94(16): 6403-6409, 2022 Apr 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
6.
Phys Med Biol ; 67(8)2022 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-35290962

RESUMO

Purpose. This investigation aims to present the characterisation and optimisation of an ultra-high pulse dose rate (UHPDR) electron beam at the PTB facility in Germany. A Monte Carlo beam model has been developed for dosimetry study for future investigation in FLASH radiotherapy and will be presented.Material and methods. The 20 MeV electron beams generated by the research linear accelerator has been characterised both in-beamline with profile monitors and magnet spectrometer, and in-water with a diamond detector prototype. The Monte Carlo model has been used to investigate six different setups to enable different dose per pulse (DPP) ranges and beam sizes in water. The properties of the electron radiation field in water have also been characterised in terms of beam size, quality specifierR50and flatness. The beam stability has also been studied.Results. The difference between the Monte-Carlo simulated and measuredR50was smaller than 0.5 mm. The simulated beam sizes agreed with the measured ones within 2 mm. Two suitable setups have been identified for delivering reference UHPDR electron beams. The first one is characterised by a SSD of 70 cm, while in the second one an SSD of 90 cm is used in combination with a 2 mm aluminium scattering plates. The two set-ups are quick and simple to install and enable an expected overall DPP range from 0.13 Gy up to 6.7 Gy per pulse.Conclusion. The electron beams generated by the PTB research accelerator have shown to be stable throughout the four-months length of this investigation. The Monte Carlo models have shown to be in good agreement for beam size and depth dose and within 1% for the beam flatness. The diamond detector prototype has shown to be a promising tool to be used for relative measurements in UHPDR electron beams.


Assuntos
Elétrons , Aceleradores de Partículas , Diamante , Método de Monte Carlo , Radiometria , Dosagem Radioterapêutica , Água
7.
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
8.
Redox Biol ; 52: 102279, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35349928

RESUMO

Although viruses are known to modify the free radical concentration in infected cells, the exact location and concentrations of such changes remain unknown. Although this information is important to understand the virus pathogenesis and design better anti-viral drugs or vaccines, obtaining it with the conventional free radical/ROS detection techniques is impossible. Here, we elucidate the utility of diamond magnetometry for studying the free radical response of baby hamster kidney-21 cells upon Semliki Forest virus infection. Specifically, we optically probe the alterations in free radical concentration near infectious viruses via measuring the spin-lattice relaxation (T1) of NV defect ensembles embedded in intracellular nanodiamonds. We performed measurements both at random locations as well as close to the virus entry by conjugating viruses to nanodiamond sensors. We observed alterations of T1, which represent the intracellular free radical concentration during the viral replication process. Moreover, relaxometry is also used to monitor real-time free radical variation during the early infectious process.


Assuntos
Nanodiamantes , Viroses , Diamante , Radicais Livres , Humanos
9.
Sci Rep ; 12(1): 5264, 2022 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-35347219

RESUMO

The present study investigates the effect of an oxidized nanocrystalline diamond (O-NCD) coating functionalized with bone morphogenetic protein 7 (BMP-7) on human osteoblast maturation and extracellular matrix mineralization in vitro and on new bone formation in vivo. The chemical structure and the morphology of the NCD coating and the adhesion, thickness and morphology of the superimposed BMP-7 layer have also been assessed. The material analysis proved synthesis of a conformal diamond coating with a fine nanostructured morphology on the Ti6Al4V samples. The homogeneous nanostructured layer of BMP-7 on the NCD coating created by a physisorption method was confirmed by AFM. The osteogenic maturation of hFOB 1.19 cells in vitro was only slightly enhanced by the O-NCD coating alone without any increase in the mineralization of the matrix. Functionalization of the coating with BMP-7 resulted in more pronounced cell osteogenic maturation and increased extracellular matrix mineralization. Similar results were obtained in vivo from micro-CT and histological analyses of rabbit distal femurs with screws implanted for 4 or 12 weeks. While the O-NCD-coated implants alone promoted greater thickness of newly-formed bone in direct contact with the implant surface than the bare material, a further increase was induced by BMP-7. It can be therefore concluded that O-NCD coating functionalized with BMP-7 is a promising surface modification of metallic bone implants in order to improve their osseointegration.


Assuntos
Proteína Morfogenética Óssea 7 , Osseointegração , Ligas , Animais , Proteína Morfogenética Óssea 7/farmacologia , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Diamante/química , Matriz Extracelular , Coelhos , Titânio
10.
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
11.
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
12.
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
13.
Phys Med Biol ; 67(7)2022 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-35226892

RESUMO

Objective.With increasing investigation of the so-called FLASH effect, the need for accurate real time dosimetry for ultra-high dose rates is also growing. Considering the ultra-high dose-per-pulse (DPP) necessary to produce the ultra-high dose rates for investigations of the FLASH effect, real time dosimetry is a major challenge. In particular, vented ionization chambers, as used for dosimetry in conventional radiotherapy, show significant deviations from linearity with increasing DPP. This is due to recombination losses in the sensitive air volume. Solid state detectors could be an alternative. Due to their good stability of the response with regard to the accumulated dose, diamond detectors such as the microDiamond could be suitable here. The aims of this work are to investigate the response of microDiamond and adapted microDiamond prototypes in ultra-high DPP electron beams, to understand the underlying effects and to draw conclusions for further detector developments.Approach.For the study, an electron beam with a DPP up to 6.5 Gy and a pulse duration of 2.5µs was used to fulfill the conditions under which the FLASH effect was observed. As a dose rate-independent reference, alanine dosimeters were used.Main Results.It has been shown that the commercially available microDiamond detectors have limitations in terms of linearity at ultra-high DPP. But this is not an intrinsic limitation of the detector principle. The deviations from linearity were correlated with the series resistance and the sensitivity. It could be shown that the linear range can be extended towards ultra-high DPP range by reducing the sensitivity in combination with a low series resistance of the detectors.Significance.The work shows that synthetic single crystal diamond detectors working as Schottky photodiodes are in principle suitable for FLASH-RT dosimetry at electron linear accelerators.


Assuntos
Diamante , Radioterapia (Especialidade) , Elétrons , Frequência Cardíaca , Radiometria
14.
Proc Natl Acad Sci U S A ; 119(8)2022 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-35193961

RESUMO

Quantum metrology enables some of the most precise measurements. In the life sciences, diamond-based quantum sensing has led to a new class of biophysical sensors and diagnostic devices that are being investigated as a platform for cancer screening and ultrasensitive immunoassays. However, a broader application in the life sciences based on nanoscale NMR spectroscopy has been hampered by the need to interface highly sensitive quantum bit (qubit) sensors with their biological targets. Here, we demonstrate an approach that combines quantum engineering with single-molecule biophysics to immobilize individual proteins and DNA molecules on the surface of a bulk diamond crystal that hosts coherent nitrogen vacancy qubit sensors. Our thin (sub-5 nm) functionalization architecture provides precise control over the biomolecule adsorption density and results in near-surface qubit coherence approaching 100 µs. The developed architecture remains chemically stable under physiological conditions for over 5 d, making our technique compatible with most biophysical and biomedical applications.


Assuntos
Técnicas Biossensoriais/métodos , Diamante/química , Nanotecnologia/métodos , Técnicas Biossensoriais/instrumentação , Espectroscopia de Ressonância Magnética/métodos , Nanopartículas/química , Nitrogênio/química
15.
J Environ Sci (China) ; 116: 103-113, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35219408

RESUMO

The simultaneous electro-oxidation of Ni (II)-citrate and electrodeposition recovery of nickel metal were attempted in a combined electro-oxidation-electrodeposition reactor with a boron-doped diamond (BDD) anode and a polished titanium cathode. Effects of initial nickel citrate concentration, current density, initial pH, electrode spacing, electrolyte type, and initial electrolyte dosage on electrochemical performance were examined. The efficiencies of Ni (II)-citrate removal and nickel metal recovery were determined to be 100% and over 72%, respectively, under the optimized conditions (10 mA/cm2, pH 4.09, 80 mmol/L Na2SO4, initial Ni (II)-citrate concentration of 75 mg/L, electrode spacing of 1 cm, and 180 min of electrolysis). Energy consumption increased with increased current density, and the energy consumption was 0.032 kWh/L at a current density of 10 mA/cm2 (pH 6.58). The deposits at the cathode were characterized by scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). These characterization results indicated that the purity of metallic nickel in cathodic deposition was over 95%. The electrochemical system exhibited a prospective approach to oxidize metal complexes and recover metallic nickel.


Assuntos
Diamante , Poluentes Químicos da Água , Boro/análise , Boro/química , Ácido Cítrico , Dioxóis , Eletrodos , Galvanoplastia , Níquel/química , Oxirredução , Poluentes Químicos da Água/análise
16.
Gen Dent ; 70(1): 56-60, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34978992

RESUMO

The objective of this study was to evaluate the efficacy of various decontamination methods and subsequent sterilization on contaminated and inoculated diamond-coated burs. One hundred forty new diamond-coated burs and 120 extracted human molars were utilized in this study. The burs were divided into 7 groups (n = 20): 1, positive control; 2, negative control; 3, new, unused burs; and 4 to 7, burs subjected to various combinations of cleaning methods (manual cleaning, use of a cleaning stone, and/or ultrasonic cleaning) after contamination. In all of the groups except group 3, the burs were sterilized and used to abrade the enamel and dentin of the sterilized extracted teeth. In groups 1 and 4 to 7, the burs were subsequently inoculated with 1 of the following microorganisms: Enterococcus faecalis (ATCC 19433), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 15442), or Geobacillus stearothermophilus (ATCC 7953). Twenty-four hours after inoculation, the burs in group 2 and groups 4 to 7 were subjected to the cleaning treatments and sterilized with steam. The burs in all 7 groups were then cultured for bacterial contamination. No growth of any bacterial type was observed in any of the groups except the positive control group. The use of a cleaning stone in combination with manual or ultrasonic cleaning resulted in the least amount of remaining tooth debris on the diamond-coated burs. The contaminated and inoculated diamond-coated burs tested in this study were successfully sterilized, and the tested bacteria were eliminated. If using a diamond-coated bur multiple times, practitioners should consider utilizing debridement with a cleaning stone followed by either manual or ultrasonic cleaning and then by a single cycle of steam sterilization.


Assuntos
Descontaminação , Diamante , Humanos , Dente Molar , Esterilização , Propriedades de Superfície
17.
Environ Sci Pollut Res Int ; 29(23): 34248-34268, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35034297

RESUMO

The placement of boulder or boulder cluster in rivers can increase or repair the complexity of river structure and the diversity of hydraulic conditions, which is very important for the habitat of many aquatic organisms. In this study, the diamond-type boulder cluster was modeled as four hemispheres exposed to a fully developed turbulent open channel flow. Numerical simulation was conducted to investigate the time-averaged flow characteristics, three-dimensional coherent structures, turbulence characteristics, and flow diversity index at different spacing ratios L/D (the ratio of the distance L to the diameter D, 1.0 ≤ L/D ≤ 3.5, where L is the center-to-center distance between two adjacent hemispheres and D is the diameter of the hemisphere). The results show that with the increase of the spacing ratio, the shear layer on the side of the gap flow gradually strengthens, and the single Karman vortex street in the wake region of the hemisphere array is suppressed. The time-averaged peak velocity in the gap flow gradually decreases with the increase of the spacing ratio, and the single of the recirculation zone behind the hemisphere array transforms into the recirculation zone behind each hemisphere, and the length of the each recirculation zone increases to the same. The turbulence intensity of the array first increases with the increase of the spacing ratio and then gradually decreases to a constant, reaching the peak intensity at L/D = 2. Based on the Shannon entropy concept, the flow diversity index in the zone of influence (ZOI) is calculated by considering the velocity and turbulence kinetic energy. The flow diversity index is the largest in the ZOI at the spacing ratio of 1.5.


Assuntos
Diamante , Ecossistema , Organismos Aquáticos , Simulação por Computador , Rios
18.
Environ Sci Pollut Res Int ; 29(19): 27677-27687, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34984609

RESUMO

The chemical and biological mechanisms of electrochemical elimination of Microcystis aeruginosa (M. aeruginosa) using boron-doped diamond (BDD) anode were comparatively explored in three different electrolytes (chloride, sulfate, and phosphate solutions). The most efficient elimination of M. aeruginosa was observed in chloride solution, which was attributed to the greatest total long-lived oxidants from the favorable formation of active chlorine. Moreover, the high permeability of active chlorine resulted in profound intracellular damages to chlorophyll-a, microcystin-LR (MC-LR), superoxide dismutase (SOD) enzyme, and DNA in the chloride system. The change of membrane permeability and degradation of the released MC-LR induced by active chlorine were further confirmed by the increase of extracellular MC-LR in the initial 5 min and a complete decay in the subsequent 15 min, while the change in morphology of algae cells was insignificant from SEM images. In sulfate and phosphate electrolytes, membrane damages were much more pronounced based on lipid peroxidation observation, although changes in cell morphology was found more significant in phosphate system. The higher concentrations of oxidants (·OH, O3, H2O2, S2O82-) generated in sulfate than in phosphate solution explained the greater efficiency of electrochemical elimination of M. aeruginosa in the sulfate electrolyte in terms of changes of cell density, OD680, chlorophyll-a, MC-LR, lipids, SOD enzyme, and DNA.


Assuntos
Microcystis , Boro/metabolismo , Cloretos , Cloro/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Diamante , Eletrodos , Eletrólitos , Peróxido de Hidrogênio/metabolismo , Microcistinas/metabolismo , Microcystis/metabolismo , Oxidantes/metabolismo , Oxirredução , Fosfatos/metabolismo , Sulfatos/metabolismo , Superóxido Dismutase/metabolismo
19.
Proc Natl Acad Sci U S A ; 119(5)2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-35082154

RESUMO

Histological imaging is essential for the biomedical research and clinical diagnosis of human cancer. Although optical microscopy provides a standard method, it is a persistent goal to develop new imaging methods for more precise histological examination. Here, we use nitrogen-vacancy centers in diamond as quantum sensors and demonstrate micrometer-resolution immunomagnetic microscopy (IMM) for human tumor tissues. We immunomagnetically labeled cancer biomarkers in tumor tissues with magnetic nanoparticles and imaged them in a 400-nm resolution diamond-based magnetic microscope. There is barely magnetic background in tissues, and the IMM can resist the impact of a light background. The distribution of biomarkers in the high-contrast magnetic images was reconstructed as that of the magnetic moment of magnetic nanoparticles by employing deep-learning algorithms. In the reconstructed magnetic images, the expression intensity of the biomarkers was quantified with the absolute magnetic signal. The IMM has excellent signal stability, and the magnetic signal in our samples had not changed after more than 1.5 y under ambient conditions. Furthermore, we realized multimodal imaging of tumor tissues by combining IMM with hematoxylin-eosin staining, immunohistochemistry, or immunofluorescence microscopy in the same tissue section. Overall, our study provides a different histological method for both molecular mechanism research and accurate diagnosis of human cancer.


Assuntos
Diamante/química , Magnetismo/métodos , Microscopia de Fluorescência/métodos , Neoplasias/patologia , Pontos Quânticos/química , Humanos , Processamento de Imagem Assistida por Computador/métodos , Nanopartículas/química , Nitrogênio/química
20.
J Am Dent Assoc ; 153(3): 221-232.e1, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35000746

RESUMO

BACKGROUND: The aim of this study was to produce a dental test soil, with 2 clinically relevant soil components, to be quantified for cleaning process validation. Another goal was to soil diamond instruments with the 2 soil components and validate the efficacy of cleaning instructions, developed and detailed in this study, using both qualitative and quantitative techniques. METHODS: To simulate worst-case clinical use conditions, the authors used each soiled instrument to prepare a 9-millimeter-deep access cavity on a noncarious extracted molar. Afterward, the authors applied a mixture of pooled human saliva and blood test soil to each instrument and air-dried it for 30 minutes. The authors cleaned each instrument using documented multistep cleaning instructions, which were then validated via both qualitative and quantitative assessment of protein and enamel-dentin residues using spectrophotometric analysis and microscopy images. RESULTS: After thorough cleaning, neither protein nor enamel-dentin residues were found at quantifiable levels (spectrophotometric analysis) on the soiled and cleaned diamond instruments, which was qualitatively verified (microscopy images). CONCLUSIONS: The results of this study show the successful development of a dental test soil with 2 clinically relevant soil components. Furthermore, using these soil components as test markers, the authors found that when the established cleaning instructions are properly followed, a soiled diamond instrument can be cleaned in a quantifiable manner. PRACTICAL IMPLICATIONS: Thorough cleaning is a critical step in reprocessing multiuse dental instruments. In accordance with US Food and Drug Administration guidance, the described process for quantification of soil components, using 2 clinically relevant soil markers, on cleaned diamond instruments can be helpful to dental instrument manufacturers in the development and validation of cleaning instructions for their reusable instruments.


Assuntos
Diamante , Solo , Instrumentos Odontológicos , Diamante/química , Humanos , Dente Molar , Estados Unidos
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