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2022 ◽  
Author(s):  
Guanghui Yu ◽  
Kejian Jiang ◽  
Wei-Min Gu ◽  
Yue Zhang ◽  
Yanting Xu ◽  
...  

A solution-processed CsPbI3 perovskite film usually suffers from nonuniform crystallization owing to its inorganic components, leading to poor surface morphology and various defects on the surface and grain boundaries. Herein,...


Minerals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 28
Author(s):  
Camila Diez ◽  
Maria Ángeles Rojo ◽  
Jesús Martín-Gil ◽  
Pablo Martín-Ramos ◽  
Manuel Garrosa ◽  
...  

Teeth are unique and complex anatomical organs that can provide relevant data about a person's health, and play an important role in forensic medicine. Teeth are exposed to food, drinks, and the microbiota of the oral cavity; therefore, they have developed a high resistance to localized demineralization. Nevertheless, the continuous demineralization–remineralization cycle present in the oral environment can be influenced by stress, medication, mineralization agents, and other factors such as individual habits, especially diet. In this study, based on attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) spectra from tooth samples of 36 patients, several parameters were estimated: the crystallinity index (CI), the phosphate/amide I ratio, and the carbonate/phosphate ratio. In addition, in eight representative samples (six of the root of the tooth and two of the enamel area of the crown), additional characterization by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) was conducted. From the FTIR data, it was observed that the highest CI values were found in patients who smoked. Further, in both root and crown samples, the intensity of the absorption band corresponding to PO43- increased in patients undergoing treatment with psychotherapeutic drugs. On the other hand, the intensity of the absorption band of the amide I group decreased with medical treatment and with the patient's biological age. Moreover, it was found that the remineralization process was more active in enamel than in the root due to direct contact with saliva. Regarding the results obtained from the X-ray powder diffractograms, exposure to psychotherapeutic drugs affected the definition of the peaks corresponding to hydroxyapatite, both in the crown and root samples. Concerning SEM results, qualitative differences in the stratification process in demineralized surfaces were observed, and EDS analyses showed some differences in the Ca/P ratio between pathological samples and control ones, but without clear patterns. The above techniques, in particular ATR-FTIR, showed promise for the investigation of the effect of changes produced in the hydroxyapatite structure in teeth and, consequently, to determine possible strategies in the diagnostic protocol.


Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 5
Author(s):  
Máté Náfrádi ◽  
Tünde Alapi ◽  
Gábor Bencsik ◽  
Csaba Janáky

In this work, the application of high-power LED365nm and commercial, low-price LED398nm for heterogeneous photocatalysis with TiO2 and ZnO photocatalysts are studied and compared, focusing on the effect of light intensity, photon energy, quantum yield, electrical energy consumption, and effect of matrices and inorganic components on radical formation. Coumarin (COU) and its hydroxylated product (7-HC) were used to investigate operating parameters on the •OH formation rate. In addition to COU, two neonicotinoids, imidacloprid and thiacloprid, were also used to study the effect of various LEDs, matrices, and inorganic ions. The transformation of COU was slower for LED398nm than for LED365nm, but r07-HC/r0COU ratio was significantly higher for LED398nm. The COU mineralization rate was the same for both photocatalysts using LED365nm, but a significant difference was observed using LED398nm. The impact of matrices and their main inorganic components Cl− and HCO3− were significantly different for ZnO and TiO2. The negative effect of HCO3− was evident, however, in the case of high-power LED365nm and TiO2, and the formation of CO3•− almost doubled the r07-HC and contributes to the conversion of neonicotinoids by altering the product distribution and mineralization rate.


Author(s):  
Montaha Behbehani ◽  
Fernando Piedade Carvalho ◽  
Saif Uddin ◽  
Nazima Habibi

This study provides the first data set of 210Po and 210Pb activity concentrations in the organic and inorganic components of several particle size classes of aerosols collected at two sampling stations in Kuwait. The 210Po concentrations in the aerosols (Bq/g) were similar in all of the particle size classes, but as most (91%) of the aerosol load was made of fine fraction particles of PM0.39–2.5 µm, most of the 210Po activity was carried by this aerosol fraction. At the two sampling stations, the 210Po/210Pb activity concentration ratios in the aerosols were similar, stable around the year, and averaged 1.5 (range 1.2–1.9), much higher than the typical activity concentration ratios of these radionuclides in unmodified (background) aerosols, with Po/Pb < 0.1. The aerosol enrichment in 210Po was likely originated from the oil industry, specifically by gas flaring and oil refining in the Gulf region. Radionuclide analysis in the organic and inorganic components of aerosols showed that the 210Po concentration in the organic component was one order of magnitude higher than the 210Po concentration in the inorganic component, in contrast with 210Pb, which displayed similar concentrations in both organic and inorganic aerosol components. The 210Po carrying organic component of aerosols was investigated and it was found to be largely composed of microorganisms with high microbial and fungi diversity, with the phyla Proteobacteria, Ascomycota, and Basidiomycota being dominant among the bacteria and with Zygomycota being dominant among the fungi. Therefore, we are facing an active concentration process of the atmospheric 210Po carried out by microorganisms, which underlies the 210Po enrichment process in the organic component of aerosols. This bioconcentration of polonium in bioaerosols was unknown.


2021 ◽  
Vol 22 ◽  
pp. 100584
Author(s):  
W. Fan ◽  
L.R. Jensen ◽  
M. Ceccato ◽  
T.S. Quaade ◽  
L. Gurevich ◽  
...  
Keyword(s):  

Author(s):  
В.В. Кузьмин ◽  
К.А. Болдырев

Изложена методика прогнозирования распространения нефтепродуктов группы BTEX (бензол, толуол, этилбензол, ксилолы) в подземных водах на основе гидрохимического моделирования с учетом изменения окислительно-восстановительных и кислотно-щелочных свойств раствора в процессе биодеградации нефтепродуктов. Представлена геохимическая модель биологического разложения нефтепродуктов комплекса BTEX на основе модифицированной кинетики Моно с учетом реакций между акцепторами, продуктами реакции биодеградации и неорганическими компонентами раствора. Приведены примеры геохимического моделирования, демонстрирующие важность учета процессов, связанных с изменением гидрогеохимической обстановки в подземных водах при разложении углеводородов. Разработанная модель может быть использована для выполнения геохимических прогнозов распространения легких нефтепродуктов в подземных водах, проведения работ в рамках оценки воздействия на природную среду, разработки систем инженерной защиты подземных вод от загрязнения нефтепродуктами. A method for predicting the spread of BTEX group oil products (benzene, toluene, ethylbenzene, xylenes) in groundwater based on hydrochemical modeling with account of changes in the redox, acidity or alkalinity of the solution during the biodegradation of oil products is stated. A geochemical model of the biological decomposition of oil products of BTEX group based on modified Mono kinetics with account of the reactions between acceptors, biodegradation products and inorganic components of the solution is presented. Examples of geochemical modeling are given that demonstrate the importance of taking into account the processes associated with the changes in the hydrogeochemical environment in groundwater during the decomposition of hydrocarbons. The developed model can be used to carry out geochemical predictions of the spread of light-end oil products in groundwater, to carry out works within the framework of estimating the environmental impact, and to develop systems for engineering protection of groundwater from oil pollution.


2021 ◽  
Author(s):  
Adam Marsh ◽  
Ehsanul Hoque Apu ◽  
Marcus Bunn ◽  
Christopher H Contag ◽  
Nureddin Ashammakhi ◽  
...  

Bone tissue loss can occur due to disease, trauma or following surgery, in each case treatment involving the use of bone grafts or biomaterials is usually required. Recent development of three-dimensional (3D) bioprinting (3DBP) has enabled the printing of customized bone substitutes. Bioinks used for bone 3DBP employ various particulate phases such as ceramic and bioactive glass particles embedded in the bioink creating a composite. When composite bioinks are used for 3DBP based on extrusion, particles are heterogeneously distributed causing damage to cells due to stresses created during flow in the matrix of the composite. Therefore, the objective of this study was to develop cell-friendly osteopromotive bioink mitigating the risk of cell damage due to the flow of particles. Towards this end, we have linked organic and inorganic components, gelatin methacryloyl (GelMA) and Ag-doped bioactive glass (Ag-BaG), to produce a hybrid material, GelMA-Ag-BaG (GAB). The distribution of the elements present in the Ag-BaG in the resulting hybrid GAB structure was examined. Rheological properties of the resulting hydrogel and its printability, as well as the degree of swelling and degradation over time, were also evaluated. GAB was compared to GelMA alone and GelMA-Ag-BaG nanocomposites. Results showed the superiority of the hybrid GAB bioink in terms of homogenous distribution of the elements in the structure, rheological properties, printability, and degradation profiles. Accordingly, this new bioink represents a major advance for bone 3DBP.


2021 ◽  
Vol 5 (10) ◽  
pp. 259
Author(s):  
Zahid Abbas ◽  
Massimiliano Dapporto ◽  
Anna Tampieri ◽  
Simone Sprio

Bioceramics are widely considered as elective materials for the regeneration of bone tissue, due to their compositional mimicry with bone inorganic components. However, they are intrinsically brittle, which limits their capability to sustain multiple biomechanical loads, especially in the case of load-bearing bone districts. In the last decades, intense research has been dedicated to combining processes to enhance both the strength and toughness of bioceramics, leading to bioceramic composite scaffolds. This review summarizes the recent approaches to this purpose, particularly those addressed to limiting the propagation of cracks to prevent the sudden mechanical failure of bioceramic composites.


2021 ◽  
Vol 7 (3) ◽  
pp. 382-391
Author(s):  
Joselúcia Da Nóbrega Dias ◽  
Endyara Larissa Araújo Pereira e Souza ◽  
Alex José Souza dos Santos ◽  
Isauremi Vieira de Assunção

Introduction: The aesthetic rehabilitation of endodontically treated teeth depends on the degree of destruction of the crown, the tooth in question, the bone support, the type of prosthesis and the types of forces to which these teeth will be submitted. The indirect composite resins have improved physical and mechanical properties thanks to the incorporation of inorganic components and multifunctional monomers with a greater number of bonding points, making them capable of solving the problems in which ceramic restorations would be indicated. Objective: To present a clinical case report of an aesthetic rehabilitation of anterior teeth with indirect composite resin as a viable and less expensive treatment alternative. Case Report: Upon clinical examination, extensive and deficient restorations were observed in the upper anterior teeth. The proposed treatment plan aesthetic rehabilitation of dental elements with ceromeres. Conclusions: This treatment represented a viable and less expensive option that can be used both in situations of great dental destruction and in small dental absences, in substitution for ceramic restorations.


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