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Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 545
Author(s):  
Pablo Verdeguer ◽  
Javier Gil ◽  
Miquel Punset ◽  
José María Manero ◽  
José Nart ◽  
...  

The passivation of titanium dental implants is performed in order to clean the surface and obtain a thin layer of protective oxide (TiO2) on the surface of the material in order to improve its behavior against corrosion and prevent the release of ions into the physiological environment. The most common chemical agent for the passivation process is hydrochloric acid (HCl), and in this work we intend to determine the capacity of citric acid as a passivating and bactericidal agent. Discs of commercially pure titanium (c.p.Ti) grade 4 were used with different treatments: control (Ctr), passivated by HCl, passivated by citric acid at 20% at different immersion times (20, 30, and 40 min) and a higher concentration of citric acid (40%) for 20 min. Physical-chemical characterization of all of the treated surfaces has been carried out by scanning electronic microscopy (SEM), confocal microscopy, and the ‘Sessile Drop’ technique in order to obtain information about different parameters (topography, elemental composition, roughness, wettability, and surface energy) that are relevant to understand the biological response of the material. In order to evaluate the corrosion behavior of the different treatments under physiological conditions, open circuit potential and potentiodynamic tests have been carried out. Additionally, ion release tests were realized by means of ICP-MS. The antibacterial behavior has been evaluated by performing bacterial adhesion tests, in which two strains have been used: Pseudomonas aeruginosa (Gram–) and Streptococcus sanguinis (Gram+). After the adhesion test, a bacterial viability study has been carried out (‘Life and Death’) and the number of colony-forming units has been calculated with SEM images. The results obtained show that the passivation with citric acid improves the hydrophilic character, corrosion resistance, and presents a bactericide character in comparison with the HCl treatment. The increasing of citric acid concentration improves the bactericide effect but decreases the corrosion resistance parameters. Ion release levels at high citric acid concentrations increase very significantly. The effect of the immersion times studied do not present an effect on the properties.


2022 ◽  
Vol 1 (2) ◽  
pp. 36-46
Author(s):  
Toheeb D. Yissa ◽  
Wahab O. Okunowo ◽  
Rukayat I. Afolayan ◽  
Abdulakeem R. Agboola ◽  
Halima Y. Lukman ◽  
...  

Background: The purpose of this study was to determine the phytochemical composition and antimicrobial potential of crude n-hexane, ethyl-acetate, methanol and aqueous extracts of Calotropis procera leaves against food spoilage microorganisms. Methods: Standard protocols were employed for the analysis of qualitative phytochemical compositions of the extracts, and antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Pseudomonas aerugenosa and Aspergillus niger. Results: Phytochemical analysis revealed the presence of tannin, saponin, alkaloids, flavonoids, reducing sugar and phenolics. Terpenoids were absent in ethyl acetate and n-hexane extracts while cardiac glycoside was absent in all extracts. All extracts produced antimicrobial activity at a varying zone of inhibition. The widest inhibition zone was produced by methanol extract (21.35±0.43 mm) on staphylococcus aureus while the lowest inhibition zone (12.05±0.45 mm) was observed in the n-hexane fraction. Similarly, the widest inhibition zone (17.24±0.95 mm) was produced by methanol on A. niger while the lowest inhibition zone (5.45±0.42 mm) was produced on n-hexane on A. niger. However, the ethyl acetate extract showed no visible inhibitory zone on all the tested microorganisms. The minimum inhibitory concentration ranged from 32 mg/ml (S. aureus and B. cereus) for ethanol extracts to 128 mg/ml (B. cereus, P. aerugenosa and A. niger) for n-hexane extract. Conclusion: The result shows that the plant is a good source of bioactive compounds that can be used as a natural alternative to a chemical agent in preserving and controlling food poisoning organisms.


2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Nazely Diban ◽  
Marián Mantecón-Oria ◽  
María T. Berciano ◽  
Alba Puente-Bedia ◽  
María J. Rivero ◽  
...  

Abstract Background Recent advances from studies of graphene and graphene-based derivatives have highlighted the great potential of these nanomaterials as migrastatic agents with the ability to modulate tumor microenvironments. Nevertheless, the administration of graphene nanomaterials in suspensions in vivo is controversial. As an alternative approach, herein, we report the immobilization of high concentrations of graphene nanoplatelets in polyacrylonitrile film substrates (named PAN/G10) and evaluate their potential use as migrastatic agents on cancer cells. Results Breast cancer MCF7 cells cultured on PAN/G10 substrates presented features resembling mesenchymal-to-epithelial transition, e.g., (i) inhibition of migratory activity; (ii) activation of the expression of E-cadherin, cytokeratin 18, ZO-1 and EpCAM, four key molecular markers of epithelial differentiation; (iii) formation of adherens junctions with clustering and adhesion of cancer cells in aggregates or islets, and (iv) reorganization of the actin cytoskeleton resulting in a polygonal cell shape. Remarkably, assessment with Raman spectroscopy revealed that the above-mentioned events were produced when MCF7 cells were preferentially located on top of graphene-rich regions of the PAN/G10 substrates. Conclusions The present data demonstrate the capacity of these composite substrates to induce an epithelial-like differentiation in MCF7 breast cancer cells, resulting in a migrastatic effect without any chemical agent-mediated signaling. Future works will aim to thoroughly evaluate the mechanisms of how PAN/G10 substrates trigger these responses in cancer cells and their potential use as antimetastatics for the treatment of solid cancers. Graphical Abstract


Author(s):  
Ravi Kumar ◽  
Atul Rana

Sterilization, which is any process, physical or chemical, that destroys all forms of life, it is used especially to destroy microorganisms, spores, and viruses. Precisely defined, sterilization is the complete destruction of all microorganisms by a suitable chemical agent or by heat, either wet steam. In this review, we discussed about various suitable techniques that used for removing of infectious agents. The heat sterilization can be applied only to the thermostable products, and chemical sterilization is also used for any types of plastic or glass materials that degrade with heat. The Gas sterilization involves exposing equipment to chemical gases in an enclosed heated or pressurized chamber.


Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8260
Author(s):  
Hyeong Geun Yu ◽  
Dong Jo Park ◽  
Dong Eui Chang ◽  
Hyunwoo Nam

Raman spectroscopy, which analyzes a Raman scattering spectrum of a target, has emerged as a key technology for non-contact chemical agent (CA) detection. Many CA detection algorithms based on Raman spectroscopy have been studied. However, the baseline, which is caused by fluorescence generated when measuring the Raman scattering spectrum, degrades the performance of CA detection algorithms. Therefore, we propose a baseline correction algorithm that removes the baseline, while minimizing the distortion of the Raman scattering spectrum. Assuming that the baseline is a linear combination of broad Gaussian vectors, we model the measured spectrum as a linear combination of broad Gaussian vectors, bases of background materials and the reference spectra of target CAs. Then, we estimate the baseline and Raman scattering spectrum together using the least squares method. Design parameters of the broad Gaussian vectors are discussed. The proposed algorithm requires reference spectra of target CAs and the background basis matrix. Such prior information can be provided when applying the CA detection algorithm. Via the experiment with real CA spectra measured by the Raman spectrometer, we show that the proposed baseline correction algorithm is more effective for removing the baseline and improving the detection performance, than conventional baseline correction algorithms.


2021 ◽  
Vol 12 (4) ◽  
Author(s):  
M. S. Doroshenko ◽  
S. O. Kostenko ◽  
P. V. Korol ◽  
A. M. Chepiha ◽  
O. V. Sydorenko ◽  
...  

The consequences of chimerization and its possible influence on the productivity of chimera offspring remain poorly understood. The objects of research were ducks (Anas platyrhynchos) of the Shanma (Shan partridge duck) and Shaoxing breeds kept at the Zhuji Guowei Poultry Development Co, Ltd, P.R.China. The study was conducted in the poultry genetics laboratory of the Zhejiang Academy of Agricultural Sciences on a duck farm of Zhejiang Generation Biological Science and Technology Co., Ltd. (Zhejiang Province, PRC). To create chimeras of ducks, the method described by Aige-Gil, Simkiss, 1991; M.T. Tagirov, 2010 was used. Blastodiscs have been isolated from freshly hatched fertilized eggs using a filter paper ring. Shanma duck embryos have been used as recipients, and Shaoxing duck embryos, homozygous for plumage color gene allele (wild type), have been used as donors. Busulfan (SigmaAldrich, United States) have been used as a chemical agent that suppresses a division of primary germ cells (PGC) of recipient embryos. A hole in an eggshell (window) of recipients (Shanma breed) have been made between a blunt and sharp ends of eggs. (This reduced a distance between an injector and an embryo needle). The recipients havebeen incubated for 8–10 hours at a temperature of 38 °C. After recipient eggs incubation for 8 hours, the windows were opened in them. Busulfan was injected into the subgerminal cavity of the embryo with a micropipette (1.5–3 μl of liquid). After busulfan injection, the empty cavity was filled with culture medium (RPMI-1640) supplemented with antibiotics (ampicillin, streptomycin), the hole was closed by plastic wrap and adhesive tape. The eggs have been incubated at a reduced temperature (+32 °C) for 24 hours with the aim of prolong the duration of busulfan action on the PGC (primary germ cells). More than 50% of embryos have been died in the first 2–3 days (after an incubation start). Head and neck disorders have been observed in the 1.2% of embryos. Busulfan injection at a concentration of 300 ng per egg have been leads to 95.0–96.3% mortality of duck embryos, concentration of 150 ng per egg, a mortality rate of 33.3–75.3% have been observed, concentration to 75 ng led to 18.75–38.5% of embryonic mortality. Analysis of the age of puberty (laying of the first egg) indicates that the chimeras matured later. If in the control group the average age of puberty was 139 ± 9 days, in the group of chimeras - 148 ± 13 days. Thus, we can attest that in our experiment, the chimeras matured later than the control animals, which may be due to the effect of busulfan in the sterilization of recipient embryos. The average weight of ducks in the control group was lower, and the group itself was more consolidated. Thus, in the control ducks weighed 1422.40 ± 57.00 g, the chimeras 1608.80 ± 94.76 g. The advantage of live weight chimeras over the control group may be due to the fact that the control group consisted of recipients served by Shanma animals. Egg production of ducks for the entire study period was 87.5 ± 0.05 % (control) 79.5±0.12 % (busulfan). The weight of eggs of ducks of two groups for the entire period was 70.62±0.199 g (control) and 71.15±0.157 g (p˂0.001). The eggs morphometric parameters of the studied ducks groups were: the average values of egg length were 6.056±0.0564 cm (control) and 6.269±0.1341cm (busulfan); egg breadth were 4.520±0.0053 cm (control) and 4.529±0.004 cm (busulfan). There were no statistical intergroup differences in the morphometric parameters of the eggs of the studied groups. In fact, we obtained results similar to the previous ones, which concerned the egg production of daughters of drake chimeras.


2021 ◽  
Vol 100 (11) ◽  
pp. 1278-1282
Author(s):  
Nadezhda Yu. Khusnutdinova ◽  
Elvira F. Repina ◽  
Denis O. Karimov ◽  
Gulnara V. Timasheva ◽  
Tat’yana G. Yakupova ◽  
...  

Introduction. The formation of toxic liver damage is carried out with the participation of various mechanisms of pathological processes. Chemicals, drugs and alcohol play a significant role. Timely and correct selection of correction drugs will help reduce the risk of toxic organ damage. The aim of the study is a comparative assessment of the hepatoprotective activity of oxymethyluracil in the early stages of exposure to various toxic agents. Materials and methods. The studies were carried out on male outbred white rats with a single injection of hepatotoxicants (carbon tetrachloride, paracetamol, ethanol) and a correction drug - oxymethyl uracil - followed by the study of biochemical parameters 1 and 3 days after the introduction of the chemical agent. Results. As a result of the studies carried out, it was found that specific metabolic changes are noted already one day after exposure to toxicants in the body of animals. Correction of tetrachloromethane and paracetamol intoxication with oxymethyl uracil leads to the normalization of the functional state of hepatocytes. Conclusion. Oxymethyl uracil exhibits hepatoprotective properties already in the early stages of acute toxic liver damage (1-3 days), being most effective in tetrachloromethane and paracetamol intoxication.


Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3999
Author(s):  
Gabriela Toader ◽  
Aurel Diacon ◽  
Traian Rotariu ◽  
Mioara Alexandru ◽  
Edina Rusen ◽  
...  

In the context of imminent threats concerning biological and chemical warfare agents, the aim of this study was the development of a new method for biological and chemical decontamination, employing non-toxic, film-forming, water-based biodegradable solutions, using a nano sized reagent together with bentonite as trapping agents for the biological and chemical contaminants. Bentonite-supported nanoparticles of Cu, TiO2, and Ag were successfully synthesized and dispersed in a polyvinyl alcohol (PVA)/glycerol (GLY) aqueous solution. The decontamination effectiveness of the proposed solutions was evaluated by qualitative and quantitative analytical techniques on various micro-organisms, with sulfur mustard (HD) and dimethyl methylphosphonate (DMMP) as contaminants. The results indicate that the peelable active nanocomposite films can be successfully used on contaminated surfaces to neutralize and entrap the hazardous materials and their degradation products. Mechanical and thermal characterization of the polymeric films was also performed to validate the decontamination solution’s potential as peelable-film generating materials. The removal efficacy from the contaminated surfaces for the tested micro-organisms varied between 93% and 97%, while for the chemical agent HD, the highest decontamination factor obtained was 90.89%. DMMP was almost completely removed from the contaminated surfaces, and a decontamination factor of 99.97% was obtained.


Author(s):  
A.V. Dvornyk ◽  
Z.Yu. Nazarenko ◽  
L.I. Lyashenko ◽  
I.M. Tkachenko

Teeth whitening is a way to restore the natural colour of teeth with applying a chemical agent that oxidizes the organic pigments of the hard dental tissues. Teeth whitening has become one of the most frequently requested dental procedures among the population. The public demands whiter, more perfect smiles, and many teeth whitening options have been made in response. To assess the changes occurring in the hard dental tissues, and, in particular, in the enamel, it is necessary to study the chemical structure of the teeth and determine the number of elements in the enamel to predict the whitening procedure outcomes and make adjustments in post-procedural care. The aim of this study was to investigate the changes in the chemical composition of the dental enamel surface after the procedure of professional hygiene and the use of 35% hydrogen peroxide for teeth whitening as the main chemical component of the whitening system. To study the trace element composition of the dental enamel, the tooth surface was segmented into areas for microanalysis. The peculiarity consisted in that the studied areas differed from the right and left sides of the tooth, because the left side in the studied teeth was the control area, and the right side allowed us to compare and contrast the chemical component of enamel in each tooth separately, by comparing the findings. The results obtained have demonstrated that there is a change in the chemical composition of the enamel in the studied teeth. The change in chemical composition indicators significantly affects the change in clinical indicators, and the strength of clinical manifestations will depend on the features of functional and structural resistance of the dental enamel. We can state that changing in the number of elements can lead to increased sensitivity during the rehabilitation period throughout which the chemical composition of the dental enamel restores.


2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Husam Abduldaem Mohammed ◽  
Aqiel Almamori ◽  
Ali A. Alwahib

This paper reports a fiber Bragg grating (FBG) as a biosensor. The FBGs were etched using a chemical agent,namely,hydrofluoric acid (HF). This implies the removal of some part of the cladding layer. Consequently, the evanescent field propagating out of the core will be closer to the environment and become more sensitive to the change in the surrounding. The proposed FBG sensor was utilized to detect toxic heavy metal ions aqueous medium namely, copper ions (Cu2+). Two FBG sensors were etched with 20 and 40 μm diameters and fabricated. The sensors were studied towards Cu2+ with different concentrations using wavelength shift as a result of the interaction between the evanescent field and copper ions. The FBG sensors showed a good response in terms of significant wavelength shift in corresponding to varying Cu2+ concentrations when immersed in aqueous mediums. The sensors exhibited excellent repeatability towards Cu ions.The results demonstrate that the smaller FBG etching diameter, the better optical response in terms of wavelength and linearity. 


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