Interesting Material Research Articles

Effect of strain on the electronic structure and optical spectra of two-dimensional monolayer GaN

The effect of compressive strain and tensile strain on the band structure and optical spectra of two-dimensional monolayer GaN has been investigated. Computations were performed within density functional-theory. The results show that tensile two-dimensional monolayer-GaN undergoes an indirect-to-direct transition, which makes the material suitable for light-emitting and laser diodes. The material of interest is found to exhibit different optical properties dependent on the strain. Besides, the absorption band becomes wider and the optical absorption coefficient is reduced negligibly by strain, making two-dimensional-GaN a good candidate for application in photovoltaics and flexible optoelectronics.

Fast and highly selective anionic azo dye removal over unique PVDF/MIL-100(Cr) mixed matrix membranes

Water pollution is a major challenge in the industrial era that gained the attention of researchers, especially for dye wastewater. Membrane technology is applied to address this issue due to its efficient and effective process. MIL-100(Cr) is a metal-organic framework that becomes an interesting material in membrane technology due to its highly porous characteristics (pore sizes of 24 Å and 29 Å), large surface area, and decent stability. In this study, polyvinylidene fluoride (PVDF) was modified with MIL-100(Cr) to fabricate PVDF/MIL-100(Cr) mixed matrix membranes (MMMs) for congo red (CR) dye removal. Furthermore, the membrane performances were determined by its permeability, selectivity, and antifouling properties. The results show that adding MIL-100(Cr) could enhance the membrane’s porosity and average pore size, which led to a boost in membrane permeability. Interestingly, the rejection of the membrane is maintained at a remarkably high level, above 95%, because of the electrostatic repulsion between the membrane surface with anionic congo red. The optimum concentration of MIL-100(Cr) is 1% (w/w), with a permeability of 50.90 L m−2 h−1 and rejection of 99.9%. Moreover, the flux recovery ratio (FRR) is around 90%, showing notable resistance to the fouling phenomena.

Onshore power supply–trends in research studies

Restrictive regulations introduced by the European Parliament and the United Nations have forced the seaport authorities to reach net zero gas emissions by 2030. An important source of pollution emitted in ports involves exhaust gas emissions from ships powered by ship engines while they are berthed in seaports. One of the ways to reduce the level of pollution and nuisance caused by ship engines is to equip ships with Onshore Power Supply (OPS). Unfortunately, still few ports can boast this type of systems at their quays. There are many publications devoted to the analysis of this phenomenon in the technical and engineering terms, but a significant part also concerns the economic, financial, logistic and organizational aspects. The aim of this research is to identify the directions of development as for research into OPS, to organize the terminology devoted to OPS, and to define scientific disciplines of research in the field of OPS. This research was conducted on the basis of the data mining method using the Scopus, EBSCO and Web of Science databases, applying the multi-stage selection of criteria. The research results may provide an interesting material for scientists to identify the gaps of research regarding OPS.

Peculiar magnetotransport properties in epitaxially stabilized orthorhombic Ru3+ perovskite LaRuO3 and NdRuO3

Complex oxides are interesting materials where multiple physical properties and functionalities can be realized by integrating different elements in a single compound. However, owing to the chemical instability, not all the combinations of elements can be materialized despite the intriguing potential expected from their magnetic and electronic properties. Here we demonstrate an epitaxial stabilization of orthorhombic Ru3+ perovskite oxides: LaRuO3 and NdRuO3, and their magnetotransport properties that reflect the difference between non-magnetic La3+ and magnetic Nd3+. Above all, an unconventional anomalous Hall effect accompanied by an inflection point in magnetoresistance is observed around 1.3 T below 1 K for NdRuO3, which we propose is possibly related to a non-coplanar spin texture on Nd3+ sublattice. These studies not only serve as a new testbed for the interplay between spin-orbit coupling and Coulomb interaction but also open a new avenue to explore topological emergent phenomena in well-studied perovskite oxides.

Mechanistic insights on 1-butene polymerization catalyzed by homogeneous single-site catalysts: a DFT computational study.

Isotactic poly (1-butene) (iPB) is an interesting semi-crystalline thermoplastic material characterized by notable physical and mechanical attributes encompassing superior creep and stress resistance, elevated toughness, stiffness, and thermal endurance. These distinctive features position iPB as a viable candidate for specific applications; however, its widespread utilization is hindered by certain inherent limitations. Indeed, iPB manifests an intricate polymorphic behavior, and the gradual and spontaneous transition of the kinetically favored form II to the thermodynamically favored form I during aging introduces alterations to the material's properties. Despite its potential, the attainment of iPB with an exceedingly high molecular mass remains elusive, particularly when employing homogeneous catalysts renowned for their efficacy in propene polymerization. In this study we analyze the mechanistic aspects governing 1-butene polymerization by using DFT calculations modelling the regioselectivity of 1-butene insertions and the termination reactions occurring after primary (1,2) and secondary (2,1) insertions. Finally, the isomerization pathways leading to the formation of 4,1 units in iPB samples synthesized by homogenous catalysts is also discussed. All these aspects, furnish a mechanistic picture of the main drawbacks of an "old" but still interesting material.

Protective potential of outer membrane vesicles derived from a virulent strain of Francisella tularensis.

Francisella tularensis secretes tubular outer membrane vesicles (OMVs) that contain a number of immunoreactive proteins as well as virulence factors. We have reported previously that isolated Francisella OMVs enter macrophages, cumulate inside, and induce a strong pro-inflammatory response. In the current article, we present that OMVs treatment of macrophages also enhances phagocytosis of the bacteria and suppresses their intracellular replication. On the other hand, the subsequent infection with Francisella is able to revert to some extent the strong pro-inflammatory effect induced by OMVs in macrophages. Being derived from the bacterial surface, isolated OMVs may be considered a "non-viable mixture of Francisella antigens" and as such, they present a promising protective material. Immunization of mice with OMVs isolated from a virulent F. tularensis subsp. holarctica strain FSC200 prolonged the survival time but did not fully protect against the infection with a lethal dose of the parent strain. However, the sera of the immunized animals revealed unambiguous cytokine and antibody responses and proved to recognize a set of well-known Francisella immunoreactive proteins. For these reasons, Francisella OMVs present an interesting material for future protective studies.

ОБРАЩЕНИЕ ГЛАВНОГО РЕДАКТОРА К ЧИТАТЕЛЯМ ВЕСЕННЕГО НОМЕРА 2024 Г. "БАЙКАЛЬСКОГО МЕДИЦИНСКОГО ЖУРНАЛА"

We present to your attention the spring issue of the “Baikal Medical Journal”, in which together we have collected the most interesting scientific materials. In the section of original articles you can familiarize yourself with the works of researchers dedicated to forests. treatment of diabetic foot. Authors V.A. Beloborodov and A.P. Frolov from the Department of General Surgery Federal State Budgetary Educational Institution of Higher Education "Irkutsk State Medical University" of the Ministry of Health of Russia (Irkutsk) in the work “Multidisciplinary approach to the diagnosis and treatment of infectious complications of syn- Diabetic Foot Droma" provides data from a retrospective analysis of 151 patient histories. Comrade with diabetic foot syndrome. The authors have proven that it is the multidisciplinary sub- the course makes it possible to preserve the supporting function of the limb in most patients and reduce the number of the incidence of high amputations in patients with diabetic foot syndrome

Acellular Dermal Matrices as an New Alternative for Treatment in Reproductive Organ Static Disorders: A Pilot Study.

Background: The study aimed to evaluate the clinical effects of utilizing acellular dermal matrix (ADM) for treating pelvic organ prolapse. The motivation behind exploring a new treatment method stems from the limited efficacy of current surgical options, which are often associated with side effects. Methods: Ten patients with reproductive organ prolapse underwent surgery at the Chair and Department of Gynecology, Obstetrics, and Gynecological Oncology in Katowice. ADM was used as a support material, with eight patients receiving double TOT and two undergoing a six-point fixation mesh procedure. Pelvic organ prolapse was evaluated pre-operatively and one month post-surgery using the Pelvic Organ Prolapse Quantification (POP-Q) System. General medical history and complaints were assessed using the short form (PFDIQ-SF20). The study included ten patients aged 39 to 71 (mean: 63.6 years), all with a history of at least one vaginal delivery (mean of two). None had undergone a cesarean section. Four patients exhibited POP-Q 3, and five had POP-Q 2. Results: The mean PFDIQ-SF20 score before surgery was 70.6 points. No major complications occurred during or after surgery. One patient experienced a vaginal fungal infection and an allergic reaction to sutures. Post-operation, ailments reduced by an average of 60.76 points, with five patients reporting no complaints. Conclusions: ADM emerges as a material of interest for gynecological surgery, with initial reports highlighting its effectiveness and optimistic safety profile. Further research is warranted to explore its potential as a promising option in pelvic organ prolapse treatment.

Design of the Nirmana Dwimatra Teaching Material Book for Students of the Polimedia Photography Department

Students in the Photography department will study various photography techniques and theories, such as portrait photography, landscape photography, product photography, and documentary photography. In the photography department, students will study the techniques and process of making images, which is a form of Dwimatra art. Through the Nirmana Dwimatra course, students will understand the techniques and methods for creating quality photographic works, which apply basic art concepts, such as perspective, color, shape, and so on. Apart from that, the Nirmana Dwimatra course can also help students in the photography department to develop their creativity and imagination, as well as understand how to combine techniques and concepts in the process of creating photographic works. Therefore, the Nirmana Dwimatra course is closely related to the photography department and can help students understand and practice photography well. Therefore, there is a need for effective and interesting teaching materials related to the Nirmana Dwimatra course specifically for the Jakarta Polymedia Photography Department.
 Keywords: textbooks, Nirmana, two dimensions, photography

Quasi-linear correlation between shear and young’s moduli in some polycrystalline ceramics

This work aims to investigate the correlation between the shear modulus and the Young’s modulus of some pore-free polycrystalline ceram-ics. Our study shows that the shear modulus correlates quasi-linearly with the Young’s modulus. The best fit was obtained using the linear model. The fit of the shear modulus G as a function of the Young modulus E obeys this linear expression: G = 0.43E - 7.7 (where both G and E are expressed in GPa). The coefficient of the correlation was found at around 0.994. Our expression was used to predict the shear modulus G of some other polycrystalline ceramics, especially: Dy2O3, Er2O3, and Y2O3 materials, which are estimated at around 65.6, 72.4, and 51.8 GPa, respectively. We attempt also to estimate the Vickers hardness of our materials of interest using an empirical expression of the literature. Unfortunately our predicted results are larger than those reported previously in the literature.

Design and study of novel Nested auxetic lattices with tunable and enhanced in-plane elastic properties

Auxetic lattices are interesting engineering materials due to Negative Poisson’s Ratio (NPR). However, auxetic lattices usually have extremely low stiffness and exhibit high anisotropy (E1/E2 >>1), severely limiting their application in high-loading environments. Attempts at increasing the stiffness of lattices typically lead to a decrease in auxeticity and an increase in anisotropy. In the current study, using novel nesting strategies, modified Sinusoidal Re-entrant Honeycomb (SRH) microstructures are developed to enhance stiffness, retain the auxeticity and introduce nearly isotropic characteristics (E1/E2 ∼ 1). Different Nested n-type (n = 0, 1,2, 3 and 4) microstructures have been studied. Translation studies involving 90° and 0° oriented lattices are undertaken to find the effect of these nesting along different lengths and combinations leading to enhanced stiffness with minor loss in auxeticity. The possibility of attaining a stiffness at least 1500 % greater than the empty lattices, while retaining significant auxeticity (Poisson’s ratio < -1) has been showcased. The proposed approach can also lead to the development of lattices that exhibit nearly isotropic characteristics. The proposed approach can be realized using the state-of-art capabilities of modern 3D printers. The proposed methods and modifications are simple yet very substantial in terms of property enhancement and can be extended to almost all types of lattices.

Defect and doping properties of sliding ferroelectric γ-InSe for photovoltaic applications

Layered van der Waals (vdw) materials have been proposed as light-absorbing materials for photovoltaic applications. InSe is a layered vdw semiconductor with ultra-high carrier mobility, strong charge transfer ability, super deformability, thermoelectricity, and optoelectronic properties. Its γ phase, or γ-InSe, was greatly stabilized by doping recently, which also exhibits sliding ferroelectricity. In this study, we propose that γ-phase InSe (γ-InSe), which was recently synthesized in a high-quality bulk phase, could be an excellent light-absorbing material candidate. Based on the first-principles simulations, bulk γ-InSe is found to possess suitable bandgap, decent absorption, and low effective mass. The investigation of defect properties reveals the major defect types, defect levels, and deep-level defects that could possibly harm the efficiency, and the deep-level defects can be significantly suppressed under Se-rich conditions. In addition, γ-InSe is intrinsically n-type, which can be tuned into weak p-type by Zn and Cd doping. We also identify the defect types of Y and Bi doping, which have been experimentally used to adjust the mechanical property of γ-InSe, and find that Y interstices could play an important role in improving the stiffness of γ-InSe. Our study provides theoretical insights for photovoltaic and other photoelectronic applications based on this interesting ferroelectric layered vdw material.

WELDING OF 1.4462 DUPLEX STEEL USED IN MEANS OF ROAD TRANSPORT

Materials with good mechanical and chemical properties (materials should be resistant to various types of corrosion) are proposed for the various structures of means of transport. For this reason, high-alloy steels, including duplex steels, are increasingly used in the automotive industry. The 1.4462 duplex steel used in means of road transport steel could be treated as an interesting high-strength stainless material used in the automotive industry. Generally, duplex steels have a high resistance to localized and uniform corrosion. The duplex and superduplex steels are assumed to be rather proper weldable materials; however, cracks could be observed both in the heat-affected zone (HAZ) and in the weld. The article analyses the influence of tubular cored metal arc (136) with active gas shield welding (process 136) parameters on the arrangement of correct joints used in tanker truck elements, as an example of welding in the automotive sector. Various mechanical tests checking the properties of joints were realized. The goal of the paper is to choose the correct welding parameters for elements of 1.4462 steel. The construction elements of a tanker truck are made by the 136 method of welding.

Regeneration of Fe-Co gel-ball: Designing uniform heterojunction with double N-doped carbon towards high-rate energy-storage abilities

Captured by high theoretical capacity and energy density, metal-sulfides have been regarded as strong candidates, but they still suffer from by polysulfides shuttling, volume swelling and slow kinetics. Herein, through the utilization of sol-gel precursors, the interesting heterostructure materials could be successfully prepared with multi-carbon layers, displaying uniform particle size and improved conductivities. Benefitting from the limitation and adsorption of carbon, the moving behaviors of polysulfides are effectively inhibited, accompanying with the alleviating volume expansion. More interestingly, the enhanced degree of interfacial redox reactions and electrochemical kinetics were noted, mainly resulted from the improved interfacial activities. As expected, used as Na-storage abilities, the capacity of optimized samples could reach up to 949.1 mAh g−1 at 0.2 A g−1, with remarkable coulombic efficiency 91.1 %. Moreover, the excellent capacity retention could be remained about 90.6 % even after 100 loops. Supported by DFT calculations, the adsorption energy of Na-atoms behaviors could be noted for heterostructure. Assisted by detailed kinetic analysis, their great charging capacity mainly originate from quickened interfacial ions/e− transfer rates and accelerated conversion-reaction kinetics. Given this, this work is expected to reveal the in-depth insight of energy-storage behaviors of hetero-structure, and offer effective designing strategies of sodium-ion storage systems.

Characterization of Thin AlN/Ag/AlN-Reflector Stacks on Glass Substrates for MEMS Applications

Thin metal layers such as silver (Ag) are being utilized for various optical and plasmonic applications as well as for electrical purposes, e.g., as transparent electrodes in display devices or solar cells. This paper focuses on optical MEMS applications such as the Fabry–Pérot interferometer (FPI). Within such filters, reflector materials such as distributed Bragg reflectors (DBRs) or subwavelength gratings (SWGs) have been widely used so far, whereas metallic thin films (MTFs) were limited in application due to their comparatively higher absorption. In this paper, thin sputtered Ag layers with thicknesses of 20, 40 and 60 nm on glass substrates have been investigated, and it is shown that the absorption is very low in the visible spectral range (VIS) and increases only in near-infrared (NIR) with increasing wavelength. Thus, we consider Ag-thin layers to be an interesting reflector material at least for the VIS range, which can be easily fabricated and integrated. However, Ag is not inert and stable when exposed to the atmosphere. Hence, it needs a passivation material. For this purpose, AlN has been chosen in this contribution, which can be deposited by sputtering as well. In this contribution, we have chosen thin AlN layers for this purpose, which can also be deposited by sputtering. Thus, various AlN/Ag/AlN-reflector stacks were created and patterned by lift-off technology preferably. The fabricated reflectors were characterized with respect to adhesion, stress, cohesion, homogeneity, and most importantly, their optical properties. It was found that the thickness of the AlN can be used to adjust the reflectance–transmittance ratio in the VIS range, and influences the adsorption in the NIR range as well. Based on the measured values of the reflectors with 40 nm Ag, an exemplary transmission filter characteristics has been predicted for a wavelength range from 400 to 800 nm. Both the maximum transmittance and the full width at half maximum (FWHM) can be tuned by variation of the AlN thickness from 20 to 60 nm.

Effect of different crosslinking agents on hybrid chitosan/collagen hydrogels for potential tissue engineering applications

Tissue engineering (TE) demands scaffolds that have the necessary resistance to withstand the mechanical stresses once implanted in our body, as well as excellent biocompatibility. Hydrogels are postulated as interesting materials for this purpose, especially those made from biopolymers. In this study, the microstructure and rheological performance, as well as functional and biological properties of chitosan and collagen hydrogels (CH/CG) crosslinked with different coupling agents, both natural such as d-Fructose (F), genipin (G) and transglutaminase (T) and synthetic, using a combination of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride with N-hydroxysuccinimide (EDC/NHS) will be assessed. FTIR tests were carried out to determine if the proposed crosslinking reactions for each crosslinking agent occurred as expected, obtaining positive results in this aspect. Regarding the characterization of the properties of each system, two main trends were observed, from which it could be established that crosslinking with G and EDC-NHS turned out to be more effective and beneficial than with the other two crosslinking agents, producing significant improvements with respect to the base CH/CG hydrogel. In addition, in vitro tests demonstrated the potential application in TE of these systems, especially for those crosslinked with G, T and EDC-NHS.

A Systematic Review of Synthesis MgO Nanoparticles and Their Applications

Recently, nanoscale biotechnology has emerged as an essential field of contemporary science and a new era in the study of materials. It draws the attention of many scientists from all over the world due to its versatility in various fields. Many physical, chemical, and biological processes are used to create biomaterials. Among the materials of interest is magnesium oxide (MgO), which can be widely used in medical and biotechnological applications due to its non-toxicity and environmental friendliness. This review article discusses various methods for the synthesis of magnesium oxide nanoparticles (MgONPs), with particular emphasis on recent developments and applications of these nanomaterials.

Powdered Cross-Linked Gelatin Methacryloyl as an Injectable Hydrogel for Adipose Tissue Engineering.

The tissue engineering field is currently advancing towards minimally invasive procedures to reconstruct soft tissue defects. In this regard, injectable hydrogels are viewed as excellent scaffold candidates to support and promote the growth of encapsulated cells. Cross-linked gelatin methacryloyl (GelMA) gels have received substantial attention due to their extracellular matrix-mimicking properties. In particular, GelMA microgels were recently identified as interesting scaffold materials since the pores in between the microgel particles allow good cell movement and nutrient diffusion. The current work reports on a novel microgel preparation procedure in which a bulk GelMA hydrogel is ground into powder particles. These particles can be easily transformed into a microgel by swelling them in a suitable solvent. The rheological properties of the microgel are independent of the particle size and remain stable at body temperature, with only a minor reversible reduction in elastic modulus correlated to the unfolding of physical cross-links at elevated temperatures. Salts reduce the elastic modulus of the microgel network due to a deswelling of the particles, in addition to triple helix denaturation. The microgels are suited for clinical use, as proven by their excellent cytocompatibility. The latter is confirmed by the superior proliferation of encapsulated adipose tissue-derived stem cells in the microgel compared to the bulk hydrogel. Moreover, microgels made from the smallest particles are easily injected through a 20G needle, allowing a minimally invasive delivery. Hence, the current work reveals that powdered cross-linked GelMA is an excellent candidate to serve as an injectable hydrogel for adipose tissue engineering.

Effects of beam shaping on copper-steel interfaces in multi-material laser beam powder bed fusion

Multi-material laser beam powder bed fusion (PBF-LB) is a promising approach to meet industrial demands for multifunctional components, due to its enhanced freedom of design. Copper and stainless steel are interesting materials to be combined due to the high electrical and thermal conductivity of copper and the mechanical strength and wear resistance of steel. However, this system suffers from copper contamination cracking (CCC), a phenomenon which leads to intergranular cracking of the steel due to penetration of liquid copper. The more these materials intermix, the greater the amount of copper that can penetrate and damage the steel. Mixing is more intense when steel is below copper during printing, a situation that cannot always be avoided due to design constraints. In this sense, this research tackles the worst scenario of printing CuCrZr onto 316L and analyses the effect of beam shaping on interface quality. For the first time, a ring-mode laser was applied to multi-material PBF-LB with the goal to reduce intermixing. It was observed that using a ring-mode laser source instead of a Gaussian beam decreases mixing of the two alloys and reduces interface defects, albeit being unable to completely suppress cracking. Grain size and texture were also affected by the beam shape, with the Gaussian beam leading to formation of small equiaxed grains along 20 layers of CuCrZr, resulting in random texture. The ring-mode laser source, on the other hand, yields columnar grains and <100> texture along the build direction. Both beam shapes were observed to induce supercooling below the liquid miscibility gap in the Cu–Fe system. Besides the expected γ-Fe and ε-Cu phases, iron was also found to crystallize in a body-centered cubic (BCC) lattice structure, which is believed to happen due to Ni depletion of the steel in Cu-rich compositions, coupled to insufficient copper within the Fe-rich liquid during solidification. BCC fractions are higher for the Gaussian beam. These differences in microstructure and BCC fraction are attributed to the high intermixing of CuCrZr and 316L when applying Gaussian beams, which is around 10 times higher than with the ring-mode laser.

Leguminous fractions as encapsulating agents of fat-soluble vitamins

Vitamins are essential micronutrients for the functioning of the human body. Vitamins can be classified as water-soluble and fat-soluble, and are obtained through diet or supplementation. Fat-soluble vitamins include vitamin A, vitamin D, vitamin E, and vitamin K. These compounds are very sensitive to external factors, including light, oxygen, pH, and temperature. Lack of compound stability, poor solubility, and low permeability can compromise the bioavailability and usefulness of fat-soluble vitamins. The methodology of encapsulation of vitamins is currently being widely studied in order to improve their transportation and usage. Proteins (including protein isolates and concentrates) and carbohydrates derived from legumes are very interesting materials to coat compounds, considering their functional properties, and the fact that they are beneficial for the environment and human health. This review describes in detail the current knowledge about the use of legume protein and carbohydrates as materials for the encapsulation of fat-soluble vitamins. The functionality, health, and environmental advantages of legume fractions (particularly soy and pea fractions) as wall materials are also discussed. Future use of legume wastewater (soaking and cooking water derived from the treatment of legumes) as wall materials is evaluated as well. The study of encapsulation of fat-soluble vitamins by leguminous fractions is mainly focused on soy and pea protein isolates and concentrates and can still be expanded, considering the numerous benefits of encapsulation they provide. Research on encapsulation using legume carbohydrates is scarce and may be interesting due to their high encapsulation efficiency and easy digestibility. Saponins, proteins, and carbohydrates present in legume wastewaters could offer useful properties to encapsulation processes, while benefiting the environment.