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Development of calcium phosphate cements for bone repair: An overview based on patent analysis

The development of calcium phosphate cement (CPC) has been regarded as a significant advance in the field of bone defect reconstruction. This bioceramic-based biomaterial is injected within the osseous cavity due to its bioactivity and rheological properties, which results in a very quick response to bone attachment and simultaneous regeneration. Furthermore, CPC may be useful as bone drug delivery systems, encapsulating cells for bone regeneration while also being capable of impregnating drugs for long-term release. Active research on CPCs for bone repair is focused on the development of an injectable, macroporous, and resorbable formula with a high compressive strength. To prove the innovation in this way, we just need to see the increase in the number of patent applications filed each year in this area around the world. This research, in the form of a patent analysis, concerns patent documents with an active legal status until 2022. The state of the art has been reviewed by introducing what has been patented concerning CPCs for bone repair. As a result, 740 active patent documents were found, and 51% of them have been published during the last seven years. According to the findings, the United States ranked as the first jurisdiction, with academic institutions from France and Spain leading the patenting way. The Cooperative Patent Classification reveals that most inventions are intended for materials or treatments for tissue regeneration, such as the reconstruction of bones with weight-bearing implants, as well as inorganic materials for grafts or prostheses, such as phosphorus-containing materials.

  • Open access
  • 13 Reads
Use opportunities of hydrated fullerene nanoparticles for hypothermic storage of industrial oyster

Background: Hydrated fullerene C60FWS as an aqueous colloidal solution exhibits a wide range of biological activity at low concentrations.

Objective: The purpose of this study was the effect of hydrated fullerene nanoparticles on the safety of Pacific oysters (Crassostrea Gigas) during hypothermic storage.

Methods: Sensory characteristics, physicochemical and biochemical properties of the control without addition and the experimental one with the addition of 10-8 M aqueous solution of C60FWS were used to assess the effect of hydrated fullerene nanoparticles on the preservation of oysters during storage at a temperature of 5°C.

Results: Monitoring the content of volatile nitrogenous compounds as accumulation products of protein degradation during autolytic and microbiological processes, water content in the muscle tissues, and also, changes in protein concentration as a criterion for a possible change in the adaptation processes of oysters during the storage time made it possible to establish significant differences for the control and experimental groups. It has been shown that these differences may indicate antioxidant properties. Changes in physicochemical and biochemical parameters correlate with changes in the organoleptic characteristics of oysters.

Conclusion: Preliminary storage of oysters in sea water with the addition of hydrated fullerene nanoparticles slows down the process of autolysis and allows it to be used as a tool to prevent changes in the quality of this food product, doubling the storage time of mollusks during transportation under anoxic and hypothermic conditions.

  • Open access
  • 25 Reads
Natural clinoptilolite nanoplatelets production by a friction-based technology

Adhesion is a crucial factor in the functionalization of a substrate by nanoparticles. The planar geometry is the most convenient shape since it provides the maximum contact area with substrate. Some nature-made materials present a nanostructured texture that may include nanosized-lamellas. Consequently, these lamellas could be cleaved by using an appropriate milling technology which is capable to apply a force in the most convenient way. In the pollution control, nanosized molecular traps have to be supported on a certain type of substrate (e.g., paper), and zeolites are frequently used for such a purpose. Indeed, zeolites-based molecular traps have been used for removing gaseous air pollutant such as SO2, H2S, NOx, etc.

The clinoptilolite is a very common type of natural zeolite having a lamellar texture. Here, an effective technique for the clinoptilolite delamination has been used. This approach is based on the applying of mild friction force to the mineral surface to progressively detach the aggregated lamellas, thus achieving both small lamellar aggregates and single crystals. It must be pointed out that small aggregates are more convenient than single lamellar crystals since the presence of a meso-porosity allows trapping of larger gaseous molecules too. Differently from other milling methods the selected approach allowed to achieve a product made of larger lamellas, that is important to enhance the adhesion.

Transmission Electron Microscopy is a powerful technique for the morphological characterization of the clinoptilolite aggregates because silico-aluminate minerals result semi-transparent to the electron beam, thus allowing the visualization of the mineral inner structure. Number of aggregated lamellas, average sizes of the aggregates and lamellas, aggregate thickness, lamellas boundary shape, etc. could be determined by the quantitative analysis of the TEM micrographs. Additional morphological information has been obtained by the Scanning Electron Microscopy analysis performed on the same samples.

  • Open access
  • 16 Reads
Optical absorption spectroscopy method for investigation of filled carbon nanotubes

Optical absorption spectroscopy (OAS) is an important method of investigation of material [1]. It analyzes the physical properties, and allows concluding about the modifications of the electronic properties [2]. Single-walled carbon nanotubes (SWCNTs) is a unique allotropic modification of carbon with interesting properties. The application of optical absorption spectroscopy to SWCNTs allows studying the optical, electronic properties of carbon nanotubes. In this paper, I overview the achievements in investigations of the SWCNTs with OAS. I discuss trends in modifications of spectra upon filling of carbon nanotubes [3-5]. This effects testify about the doping with charge transfer. The modified electronic properties can find applications in nanoelectronics, solar cells, catalysts, thermoelectric power generation, light emission, biomedicine.

[1] M. V. Kharlamova. Electronic properties of pristine and modified single-walled carbon nanotubes. Physics-Uspekhi 2013, 56, 1047-1073.

[2] M. V. Kharlamova. Advances in tailoring the electronic properties of single-walled carbon nanotubes. Progress in Materials Science 2016, 77, 125-211.

[3] M. V. Kharlamova et al. Comprehensive spectroscopic characterization of high purity metallicity-sorted single-walled carbon nanotubes. Physica Status Solidi b 2015, 252, 2512-2518.

[4] M. V. Kharlamova et al. Single-walled carbon nanotubes filled with nickel halogenides: atomic structure and doping effect. Physica Status Solidi B 2012, 249, 2328-2332.

[5] M. V. Kharlamova et al. Acceptor doping of single-walled carbon nanotube by encapsulation of zinc halogenides. Eur. Phys. J. B. 2012, 85, 34.

  • Open access
  • 7 Reads
Near edge X-ray absorption fine structure spectroscopy: analysis of filled carbon nanotubes

Near edge X-ray absorption fine structure spectroscopy (NEXAFS) is a method of investigation of material that studies fine structure near band edge [1]. This method is very useful for the investigation of carbon materials [2]. The filled single-walled carbon nanotubes (SWCNTs) is promising materials for applications in various fields, such as nanoelectronics, spintronics, biomedicine. Here, I overview the work on the investigations of filled SWCNTs with NEXAFS. I discuss trends in the spectra upon filling, modifications that testify about the changes in chemical and electronic properties [3]. New features in the spectra may testify about the formation of bonds in nanocomposites consisting from carbon nanotubes with filler inside. This is very important, complementary method for other investigation techniques of carbon material, such as Raman spectroscopy, optical absorption spectroscopy, photoemission spectroscopy. The combination of methods is important for applications of filled SWCNTs and can be used also in situ in devices.

[1] M. V. Kharlamova. Electronic properties of pristine and modified single-walled carbon nanotubes. Physics-Uspekhi 2013, 56, 1047-1073.

[2] M. V. Kharlamova. Advances in tailoring the electronic properties of single-walled carbon nanotubes. Progress in Materials Science 2016, 77, 125-211.

[3] M. V. Kharlamova et al. Inner tube growth properties and electronic structure of ferrocene-filled large diameter single-walled carbon nanotubes. Physica Status Solidi B 2013, 250, 2575-2580.

  • Open access
  • 23 Reads
An investigation of the optimal conditions for the green synthesis of silver nanoparticles using an aqueous extract from the plant Agrimonia eupatoria L.

In green synthesis, nanoparticles are synthesized using inexpensive and environmentally friendly synthesis technologies. Organism extracts can be used both as reducing agents and as stabilizers in the synthesis of nanoparticles. Silver nanoparticles have characteristic physical, chemical, and biological properties. Their catalytic activity and antibacterial activity are very significant, but also excellent for the possibility of application in nanobiotechnological research.

In this research, we used silver nitrate and an aqueous extract of the plant Agrimonia eupatoria L. for the synthesis of silver nanoparticles (AgNPs). Agrimonia eupatoria L. (common name: agrimony) belongs to the family Rosaceae (Tribe: Sanguisorbeae). The plant is known for being used as a raw material for the extraction of medicinal ingredients or the production of medicines in the pharmaceutical industry. The plant has antioxidant and antibacterial properties, but also anti-inflammatory, neuroprotective, antidiabetic, hepatoprotective, and anticancer properties.

The optimal conditions for this green synthesis were examined: the concentration of starting substances, pH value, and temperature. Silver nitrate was dissolved in concentrations of 5 mM, 10 mM, and 20 mM. The pH of the reaction mixtures was adjusted to 4, 6, and 8 using solutions of 0.1 M NaOH and 0.1 M HNO3. The reaction mixture was heated to 25°C and 50°C on a magnetic stirrer under controlled conditions. Visual color change (from light yellow to dark brown) and UV-Vis s spectrophotometry were used to monitor the process of AgNPs formation.

Spectra of formed nanoparticles (200–800 nm) were recorded, and the highest peaks were found between 425–500 nm, suggesting AgNPs were formed. The best conditions for the most increased AgNPs yield production were а 5 mM concentration of AgNO3, 1% concentration of extract, reaction temperature of 25 °C, pH=6, and a reaction time of 3 h for synthesis.

  • Open access
  • 30 Reads
Investigation of Transition metal ion Cu2+ and Mg2+ Doped Zinc Aluminate (ZnAl2O4) and their Structural, Spectral, Optical, and Dielectric study for Storage applications.
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Spinel bimetallic oxides nanomaterials have attracted attention due to their unique crystal structure, excellent optical and dielectric properties, high chemical and thermal stability, low surface acidity, etc. As a typical spinel semiconductor with wide band gap (Eg = 3.8 eV), Zinc aluminate (ZnAl2O4) has been widely investigated in the field of catalysis, hydrogen storage, sense, display. It has also attracted attention as a phosphor carrier material for use in thin-film electroluminescent displays, mechano-optical voltage sensors and voltage visualization devices. Herein, Zn1-xCu0xAl2O4 (x = 0.00 and 0.10) has been synthesized through the sol–gel auto combustion technique. The structural, spectral, optical, morphological and dielectric properties of the synthesized nanoparticles were analyzed. The X-ray diffraction analysis revealed the single phase spinel structure. The crystallite size in the range of 55-65 nm was ascertained by the Scherrer formula. The substitution of copper and magnesium in Zinc spinel aluminates was found to have a significant effect on crystallite size, lattice strain, micro-strain and dislocation density. Transition metal ion doped aluminates samples evinced a decrease in the optical band gap energy from Eg = 3.36 to 3.20 eV. Surface morphology of the materials has been studied through the HRSEM-EDX analysis. The dielectric properties were explored in the frequency range 1 Hz to 10 MHz. Impedance study revealed the grain boundaries to be dominant as a function of Cu2+ and Mg2+ content. Inverse relation of ac frequency with the dielectric constant exposed the existence of Maxwell–Wagner type interfacial polarization. The conducting and resistive grain boundaries play a vital role in understanding the dielectric relaxation in the material. From the observed electrical parameters, it can be propounded that the prepared spinels hold semiconducting nature and can be employed as a dielectric in low-frequency devices. They also serve as potential candidate in optoelectronics, magnetic and catalysis applications.

  • Open access
  • 17 Reads

One of the strategies of solving greenhouse problem is transformation CO2 to valuable chemicals such as carbamates, cyclic carbonates, oxazolidones and tetramic acids. Among these chemicals, cyclic carbonates can be used in lithium-ion batteries as electrolyte. Cyclic carbonate production via CO2 cycloaddition is feasible way in terms of thermodynamic and atom economy. However, CO2 transformation processes require high energy. So, researchers have been studied several catalysts which possess high CO2 uptake capacity such as zeolites, porous carbon, metal organic frameworks (MOFs). As a novel class of porous materials, Covalent Organic Frameworks (COFs) can be achieve success even under humid conditions in cyclic carbonate production via CO2 cycloaddition [1]. The unique properties of COFs are low density, large surface area, adjustable pore size and structure [2]. One of the studies of this area was Tong et al. (2022). They synthesized salen-COF via solvothermal method and impregnated cobalt on this catalyst. Under the optimized conditions (22.5 mg Co-based catalyst, 20 bar, 120 °C, solvent-free), researchers obtained 99% propylene carbonate selectivity and 98% propylene oxide conversion [3]. Haque et al. (2021) synthesized Zn embedded RIO-1. They carried out the reaction at room temperature under 1 atm CO2 pressure. After 10 h reaction time, they obtained 100% α-alkylidene cyclic carbonate selectivity for cyclic carbonates and 100% propargyl alcohol conversion [4].

[1] Sengupta, M., Bag, A., Ghosh, S., Mondal, P., Bordoloi, A., & Islam, S. M., Journal of CO2 Utilization, 2019, 34, 533-542. [2]Ding, S. Y., & Wang, W., Chemical Society Reviews, 2013, 42(2), 548-568. [3]Tong, Y., Cheng, R., Dong, H., & Liu, B. Journal of Porous Materials, 2022, 29, 1253–1263. [4]Haque, N., Biswas, S., Ghosh, S., Chowdhury, A. H., Khan, A., & Islam, S. M. ACS Applied Nano Materials, 2021, 4(8), 7663-7674.

  • Open access
  • 8 Reads
Detection of CO2 pollutions based on Phononic crystals

Phononic crystal sensor is a novel technology for sensing applications with high performance. The present work
proposes theoretically a design of gas (CO2) sensor based on a one-dimensional (1D) porous silicon (PSi) phononic
crystal (PnC) sandwiched between two thin rubber layers. The transfer matrix method (TMM) was used for
the numerical modeling of the acoustic waves spectra through the 1DPSi-PnC sensor structure. The results
showed that a resonant mode was created inside the transmission spectrum as a result of the presence of the twosided
rubber layers. Also, the position of the resonant mode was invariant with changing CO2 concentration,
temperature, and pressure. On the contrary, the intensity of the transmitted mode is very sensitive to any change
in these parameters. With increasing the CO2 concentration (from 0% to 90%) and pressure (from 2 atm to 6
atm), the intensity of the resonant mode are significantly increased. While, with increasing temperature (from 20
�C to 200 �C), the intensity of the resonant mode is decreased. These results are correlated directly to the density
of the CO2/air mixture. Therefore, the proposed 1DPSi-PnC sensor can measure CO2 pollutions in the surrounding
air over a wide range of concentration, temperature, and pressure values.
The merits of a gas sensor based on porous materials and PnC structure are numerous. For example, the ease of
fabrication, working under tough conditions, and its capability to sense CO2 pollutions from the surrounding air
directly. Also, the proposed sensor can be developed as a monitor for many gases in industrial and biomedical
applications. Moreover, porous materials enable the proposed design to be compatible with other fluidic components
specifically liquids. Thereby, allowing the proposed gas sensor to be replicated for various fluidic sensing

  • Open access
  • 14 Reads
Electron-beam action induced CaSi2 crystal nucleation and growth at the CaF2 epitaxy on Si

The effects of electron-beam irradiation (electron energy 20 keV, current density 50 μA/m2) on CaF2 films epitaxially grown on Si(111) has been studied with reflection high-energy electron diffraction (RHEED) and Raman spectroscopy (RS). It was found that the electron beam action leads to the CaSi2 layer synthesis as during the epitaxial growth of СаF2 films and with irradiation after formation of CaF2 films. The radiation-induced phenomena of CaSi2 crystal growth were investigated, both directly during the epitaxial CaF2 growth on Si (111) and film irradiation with fast electrons on Si(111) after its formation of CaF2 films with keeping the specified film thickness, substrate temperature and radiation dose. Irradiation in the process of the epitaxial CaF2 film growth leads to the formation of CaSi2 nanowhiskers oriented along the direction <110>. The electron irradiation of the formed films, under similar conditions, leads to the homogeneous nucleation of CaSi2 crystals and their proliferation as inclusions in the CaF2 film. It was shown that both approaches lead to the formation of CaSi2 crystals of the 3R polymorph in the irradiated region of a 10 nm thick CaF2 layer. The crystal structures of CaSi2 was found to depend on thickness of deposited СаF2 films: it is trigonal rhombohedral modification tr3 for thin (<20nm) СаF2 films and trigonal rhombohedral modification tr6 for thicker one.

The reported study was funded by RFBR and ROSATOM, project number 20-21-00028