bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of the Piezoresistive Behavior of Poly (vinylidene fluoride)/Carbon Nanotube Composites by the Addition of Inorganic Semiconductor Nanoparticles
Authors: Kaplan Müslüm , Alp Emre , Krause Beate , Pötschke Petra
Published: February 2024

Conductive polymer composites (CPCs), obtained by incorporating conductive fillers into a polymer matrix, are suitable for producing strain sensors for structural health monitoring (SHM) in infrastructure. Here, the effect of the addition of inorganic semiconductor nanoparticles (INPs) to a poly (vinylidene fluoride) (PVDF) composite filled with multi-walled carbon nanotubes (MWCNTs) on the piezoresistive behavior is investigated. INPs with different morphologies and sizes are synthesized by a hydrothermal method. The added inorganic oxide semiconductors showed two distinct morphologies, including different phases. While particles with flower-like plate morphology contain phases of orth-ZnSnO3 and SnO, the cauliflower-like nanoparticles contain these metal oxides and ZnO. The nanoparticles are characterized by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD), and the nanocomposites by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Cyclic tensile testing is applied to determine the strain-sensing behavior of PVDF/1 wt% MWCNT nanocomposites with 0–10 wt% inorganic nanoparticles. Compared to the PVDF/1 wt% MWCNT nanocomposite, the piezoresistive sensitivity is higher after the addition of both types of nanoparticles and increases with their amount. Thereby, nanoparticles with flower-like plate structures improve strain sensing behavior slightly more than nanoparticles with cauliflower-like structures. The thermogravimetric analysis results showed that the morphology of the semiconductor nanoparticles added to the PVDF/MWCNT matrix influences the changes in thermal properties.
Effect of Oxidation Process on Mechanical and Tribological Behaviour of Titanium Grade 5 Alloy
Authors: Saier Abdulsalam , Esen Ismail , Ahlatci Hayrettin , Keskin Esma
Published: February 2024

In this study, microstructural characterization, mechanical (tensile and compressive) properties, and tribological (wear) properties of Titanium Grade 5 alloy after the oxidation process were examined. While it is observed that the grey contrast coloured α grains are coaxial in the microstructures, it is seen that there are black contrast coloured β grains at the grain boundaries. However, in oxidised Titanium Grade 5, it is possible to observe that the α structure becomes larger, and the number and density of the structure increases. Small-sized structures can be seen inside the growing α particles and on the β particles. These structures are predicted to be Al-Ti/Al-V secondary phases. The nonoxidised alloy matrix and the OL layer exhibited a macrolevel hardness of 335 ± 3.21 HB and 353 ± 1.62 HB, respectively. The heat treatment increased Vickers microhardness by 13% in polished and etched nonoxidised and oxidised alloys, from 309 ± 2.08 HV1 to 352 ± 1.43 HV1. The Vickers microhardness value of the oxidised sample was 528 ± 1.74 HV1, as a 50% increase was noted. According to their tensile properties, oxidised alloys showed a better result compared to nonoxidised alloys. While the peak stress in the oxidised alloy was 1028.40 MPa, in the nonoxidised alloy, this value was 1027.20 MPa. It is seen that the peak stresses of both materials are close to each other, and the result of the oxidised alloy is slightly better. When we look at the breaking strain to characterise the deformation behaviour in the materials, it is 0.084 mm/mm in the oxidised alloy; In the nonoxidised alloy, it is 0.066 mm/mm. When we look at the stress at offset yield of the two alloys, it is 694.56 MPa in the oxidised alloy; it was found to be 674.092 MPa in the nonoxidised alloy. According to their compressive test properties, the maximum compressive strength is 2164.32 MPa in the oxidised alloy; in the nonoxidised alloy, it is 1531.52 MPa. While the yield strength is 972.50 MPa in oxidised Titanium Grade 5, it was found to be 934.16 MPa in nonoxidised Titanium Grade 5. When the compressive deformation oxidised alloy is 100.01%, in the nonoxidised alloy, it is 68.50%. According to their tribological properties, the oxidised alloy provided the least weight loss after 10,000 m and had the best wear resistance. This material’s weight loss and wear coefficient at the end of 10,000 m are 0.127 ± 0.0002 g and (63.45 ± 0.15) × 10−8 g/Nm, respectively. The highest weight loss and worst wear resistance have been observed in the nonoxidised alloy. The weight loss and wear coefficients at the end of 10,000 m are 0.140 ± 0.0003 g and (69.75 ± 0.09) × 10−8 g/Nm, respectively. The oxidation process has been shown to improve the tribological properties of Titanium Grade 5 alloy.
Ion Implantation Combined with Heat Treatment Enables Excellent Conductivity and Corrosion Resistance of Stainless Steel Bipolar Plates for Hydrogen Fuel Cells
Authors: Wang Ruijuan , Ding Li , Pan Yong , Zhang Xin , Yang Meng , Zhu Chengfei
Published: February 2024

316 L stainless steel is an ideal bipolar plate material for a proton exchange membrane fuel cell (PEMFC). However, the thickening of the passivation film on the stainless steel surface and the dissolution of corrosive ions during operation will affect the durability of the PEMFC. Herein, a heterogeneous layer is prepared on the surface of 316 L stainless steel through dual ion implantation of molybdenum ion and carbon ion combined with heat treatment to promote the corrosion resistance and conductivity of the bipolar plate. The ion implantation technique resulted in a uniform distribution of Mo and C elements on the surface of 316 L stainless steel, with a modified layer depth of about 70–80 nm. The electrical conductivity of the ion implanted samples was significantly improved, and the interfacial contact resistance was reduced from 464.25 mΩ × cm2 to 42.49 mΩ × cm2. Heat treatment enhances the surface homogenization, repairs the defects of irradiation damage, and improves the corrosion resistance of stainless steel. The corrosion current density of (Mo+C)-600 samples decreased from 1.21 × 10−8 A/cm2 to 2.95 × 10−9 A/cm2 under the long-term corrosion condition of 4 h. These results can provide guidance for the modification of stainless steel bipolar plates.
Durability Improvement of Pumice Lightweight Aggregate Concrete by Incorporating Modified Rubber Powder with Sodium Silicate
Authors: Wang Hailong , Shu Libin , Ma Kuaile , He Xingxing
Published: February 2024

To improve the durability of pumice lightweight aggregate concrete applied in cold and drought areas, sodium silicate-modified waste tire rubber powder is used to treat the pumice lightweight aggregate concrete. The pumice lightweight aggregate concrete studied is mainly used in river lining structures. It will be eroded by water flow and the impact of ice and other injuries, resulting in reduced durability, and the addition of modified rubber will reduce the damage. The durability, including mass loss rate and relative dynamic elastic modulus of pumice lightweight aggregate concrete with different sodium silicate dosages and rubber power particle sizes, is analyzed under freeze-thaw cycles, and the microstructure is further characterized by using microscopic test methods such as nuclear magnetic resonance tests, ultra-depth 3D microscope tests, and scanning electron microscopy tests. The results showed that the durability of pumice lightweight aggregate concrete is significantly improved by the addition of modified waste tire rubber powder, and the optimum durability is achieved when using 2 wt% sodium silicate modified rubber power with a particle size of 20, and then the mass loss rate decreased from 4.54% to 0.77% and the relative dynamic elastic modulus increased from 50.34% to 64.87% after 300 freeze-thaw cycles compared with other samples. The scanning electron microscopy test result showed that the surface of rubber power is cleaner after the modification of sodium silicate, so the bonding ability between rubber power and cement hydration products is improved, which further improved the durability of concrete under the freeze-thaw cycle. The results of the nuclear magnetic resonance test showed that the pore area increased with the number of freeze-thaw cycles, and the small pores gradually evolved into large pores. The effect of sodium silicate on the modification of rubber power with different particle sizes is different. After the treatment of 2 wt% sodium silicate, the relationship between the increased rate of pore area and the number of freezing-thawing cycles is 23.8/times for the pumice lightweight aggregate concrete containing rubber power with a particle size of 20 and 35.3/times for the pumice lightweight aggregate concrete containing a particle size of 80 rubber power, respectively.
Large-Scale Green Synthesis of Magnesium Whitlockite from Environmentally Benign Precursor
Authors: Raiseliene Ruta , Linkaite Greta , Zarkov Aleksej , Kareiva Aivaras , Grigoraviciute Inga
Published: February 2024

Magnesium whitlockite (Mg-WH) powders were synthesized with remarkable efficiency via the dissolution–precipitation method by employing an environmentally benign precursor, gypsum. Under optimized conditions, each 5.00 g of initial gypsum yielded an impressive amount of 3.00 g (89% yield) of Mg-WH in a single batch. Remarkably, no XRD peaks attributable to impurity phases were observed, indicating the single-phase nature of the sample. FT-IR analysis confirmed the presence of the PO43− and HPO42− groups in the obtained Mg-WH phase. The SEM-EDX results confirmed that Mg-WH crystals with homogeneous Ca, Mg, P, and O distributions were obtained. In previously published research papers, the synthesis of Mg-WH has been consistently described as a highly intricate process due to material formation within a narrow pH and temperature range. Our proposed synthesis method is particularly compelling as it eliminates the need for meticulous monitoring, presenting a notable improvement in the quest for a more convenient and efficient Mg-WH synthesis. The proposed procedure not only emphasizes the effectiveness of the process, but also highlights its potential to meet significant demands, providing a reliable solution for large-scale production needs in various promising applications.
Preparation of GO/Diatomite/Polyacrylonitrile Functional Separator and Its Application in Li–S Batteries
Authors: Yang Jing , Xiao Wenjie , Wu Xiaoyu , Zha Yitao , Liu Sainan
Published: February 2024

Lithium–sulfur (Li–S) batteries have received extensive attention due to their numerous advantages, including a high theoretical specific capacity, high energy density, abundant reserves of sulfur in cathode materials, and low cost. Li–S batteries also face several challenges, such as the insulating properties of sulfur, volume expansion during charging and discharging processes, polysulfide shuttling, and lithium dendritic crystal growth. In this study, a composite of a porous multi-site diatomite-loaded graphene oxide material and a PAN fiber membrane is developed to obtain a porous and high-temperature-resistant GO/diatomite/polyacrylonitrile functional separator (GO/DE/PAN) to improve the electrochemical performance of Li–S batteries. The results show that the use of GO/DE/PAN helps to inhibit lithium phosphorus sulfide (LPS) shuttling and improve the electrolyte wetting of the separator as well as the thermal stability of the battery. The initial discharge capacity of the battery using GO/DE/PAN is up to 964.7 mAh g−1 at 0.2 C, and after 100 cycles, the reversible capacity is 683 mAh g−1 with a coulombic efficiency of 98.8%. The improved electrochemical performance may be attributed to the porous structure of diatomite and the layered composite of graphene oxide, which can combine physical adsorption and spatial site resistance as well as chemical repulsion to inhibit the shuttle effect of LPS. The results show that GO/DE/PAN has great potential for application in Li–S batteries to improve their electrochemical performance.
Analysis of Roughness, the Material Removal Rate, and the Acoustic Emission Signal Obtained in Flat Grinding Processes
Authors: Sender Piotr , Buj-Corral Irene , Álvarez-Flórez Jesús
Published: February 2024

In this work, the analysis of the acoustic emission (AE) signal in grinding processes is addressed. The proposed analysis method decomposes the acoustic signal into three frequency ranges. The total energy of each range is determined, as well as the highest frequency. Different grinding experiments were carried out, according to a full factorial design of experiments (DOE), in which feed speed, depth of cut, and transversal step (table cross feed) were varied. Arithmetic average roughness Ra and the material removal rate (MRR) were determined. It was observed that Ra depends mainly on the transversal step, followed by feed speed and the interaction between the transversal step and depth of cut, while MRR is greatly influenced by the transversal step. According to multi-objective optimization with the Derringer–Suich function, in order to simultaneously minimize Ra and maximize MRR, a transversal step of 9 mm per longitudinal pass, feed speed of 20 m/min, and depth of cut of 0.020 mm should be selected.
Equivalent Continuum Modeling for Flexible Slender Quadrilateral Truss Structure
Authors: Li Bo , Wang Yan , Liu Yipeng , Tao Jianguo , Ren Hui , Yang Hui
Published: February 2024

A space in-orbit service simulation experiment platform is a type of equipment platform that allows spacecraft such as satellites and deep-space explorers to be adequately ground tested before launch. The function of the crane system is to drive the target spacecraft to perform a large-scale movement. This study focuses on the dynamics of a space in-orbit service simulation experiment platform with suspension rope and column quadrilateral truss structure as connecting devices. A space in-orbit service simulation experiment platform with a column quadrilateral truss structure as a connecting device is studied, modeled as a crane system–column quadrilateral truss structure–target spacecraft system. For the column quadrilateral truss structure, the equivalent beam model is used to make it equivalent based on the Timoshenko beam theory. The required equivalent stiffness parameters are determined and adjusted. The relative error between the finite element model and the corrected equivalent beam model of the column quadrilateral truss structure is no more than 4.7%. The results indicate that the accuracy of the modified equivalent beam model is sufficient. The improved equivalent beam model has excellent precision according to numerical calculations, and the derived equivalent stiffness parameters may be employed directly in dynamic modeling.
Structural Characteristics and Improved Thermal Stability of HDPE/Calcium Pimelate Nanocomposites
Authors: Samiotaki Christina , Tarani Evangelia , Karavasili Dimitra , Zamboulis Alexandra , Chrissafis Konstantinos , Bikiaris Dimitrios N.
Published: February 2024

In the present research work, calcium pimelate (CaPim) was synthesized and investigated as an additive for high-density polyethylene (HDPE). HDPE/CaPim nanocomposites were prepared by melt-mixing, with CaPim content ranging from 0.1% to 1%, affording white homogeneous materials. The chemical structure of the nanocomposites and the incorporation of CaPim was confirmed by infrared spectroscopy. The surficial morphology and the additive distribution were examined by scanning electron microscopy. Differential scanning calorimetry and X-ray diffraction measurements showed that the thermal transitions and crystal structure of HDPE are not affected by the incorporation of CaPim, while the mechanical properties are retained overall. This study focuses on the thermal degradation of HDPE nanocomposites, investigating the degradation mechanism and kinetic parameters through various analytical methods. Isoconversional techniques, including the Friedman method, Vyazovkin analysis, and Ozawa Flynn Wall analysis, were employed to calculate activation energies (Eα). The degradation mechanism and kinetic triplet were determined based on a multivariate non-linear regression method (model-fitting). Finally, the presence of a CaPim additive was shown to increase the Eα of thermal degradation, consistent with the calculated dependence of Eα on the degree of conversion and the improved thermal stability of the HDPE matrix.
On the Optimal Point of the Weighted Simpson Index
Authors: Casquilho José Pinto , Mena-Matos Helena
Published: February 2024

In this short communication, following a brief introduction, we undertake a comprehensive analytical study of the weighted Simpson index. Our primary emphasis concerns the precise determination of the optimal point (minimizer) coordinates and of the minimum value of the index, a differentiable convex function, which is related to the harmonic mean concept. Furthermore, we address and solve the inversion problem and show the tight connection between both approaches. Last, we give some insights and final remarks on this subject.
Development of a Prognostic Scoring System for Tracheostomized Patients Requiring Prolonged Ventilator Care: A Ten-Year Experience in a University-Affiliated Tertiary Hospital
Authors: Jang Hyojin , Yoo Wanho , Seong Hayoung , Kim Saerom , Kim Soo Han , Jo Eun-Jung , Eom Jung Seop , Lee Kwangha
Published: February 2024

Background and Objectives: This study aimed to assess the value of a novel prognostic model, based on clinical variables, comorbidities, and demographic characteristics, to predict long-term prognosis in patients who received mechanical ventilation (MV) for over 14 days and who underwent a tracheostomy during the first 14 days of MV. Materials and Methods: Data were obtained from 278 patients (66.2% male; median age: 71 years) who underwent a tracheostomy within the first 14 days of MV from February 2011 to February 2021. Factors predicting 1-year mortality after the initiation of MV were identified by binary logistic regression analysis. The resulting prognostic model, known as the tracheostomy-ProVent score, was computed by assigning points to variables based on their respective ß-coefficients. Results: The overall 1-year mortality rate was 64.7%. Six factors were identified as prognostic indicators: platelet count < 150 × 103/μL, PaO2/FiO2 < 200 mmHg, body mass index (BMI) < 23.0 kg/m2, albumin concentration < 2.8 g/dL on day 14 of MV, chronic cardiovascular diseases, and immunocompromised status at admission. The tracheostomy-ProVent score exhibited acceptable discrimination, with an area under the receiver operating characteristic curve (AUC) of 0.786 (95% confidence interval: 0.733–0.833, p < 0.001) and acceptable calibration (Hosmer–Lemeshow chi-square: 2.753, df: 8, p = 0.949). Based on the maximum Youden index, the cut-off value for predicting mortality was set at ≥2, with a sensitivity of 67.4% and a specificity of 76.3%. Conclusions: The tracheostomy-ProVent score is a good predictive tool for estimating 1-year mortality in tracheostomized patients undergoing MV for >14 days. This comprehensive model integrates clinical variables and comorbidities, enhancing the precision of long-term prognosis in these patients.
Utilization of Augmented Reality Head-Mounted Display for the Surgical Management of Thoracolumbar Spinal Trauma
Authors: Kann Michael Ryan , Ruiz-Cardozo Miguel A. , Brehm Samuel , Bui Tim , Joseph Karan , Barot Karma , Trevino Gabriel , Carey-Ewend Abigail , Singh Som P. , De La Paz Matthew , Hanafy Ahmed , Olufawo Michael , Patel Rujvee P. , Yahanda Alexander T. , Perdomo-Pantoja Alexander , Jauregui Julio J. , Cadieux Magalie , Pennicooke Brenton , Molina Camilo A.
Published: February 2024

Background and Objectives: Augmented reality head-mounted display (AR-HMD) is a novel technology that provides surgeons with a real-time CT-guided 3-dimensional recapitulation of a patient’s spinal anatomy. In this case series, we explore the use of AR-HMD alongside more traditional robotic assistance in surgical spine trauma cases to determine their effect on operative costs and perioperative outcomes. Materials and Methods: We retrospectively reviewed trauma patients who underwent pedicle screw placement surgery guided by AR-HMD or robotic-assisted platforms at an academic tertiary care center between 1 January 2021 and 31 December 2022. Outcome distributions were compared using the Mann–Whitney U test. Results: The AR cohort (n = 9) had a mean age of 66 years, BMI of 29.4 kg/m2, Charlson Comorbidity Index (CCI) of 4.1, and Surgical Invasiveness Index (SII) of 8.8. In total, 77 pedicle screws were placed in this cohort. Intra-operatively, there was a mean blood loss of 378 mL, 0.78 units transfused, 398 min spent in the operating room, and a 20-day LOS. The robotic cohort (n = 13) had a mean age of 56 years, BMI of 27.1 kg/m2, CCI of 3.8, and SII of 14.2. In total, 128 pedicle screws were placed in this cohort. Intra-operatively, there was a mean blood loss of 432 mL, 0.46 units transfused units used, 331 min spent in the operating room, and a 10.4-day LOS. No significant difference was found between the two cohorts in any outcome metrics. Conclusions: Although the need to address urgent spinal conditions poses a significant challenge to the implementation of innovative technologies in spine surgery, this study represents an initial effort to show that AR-HMD can yield comparable outcomes to traditional robotic surgical techniques. Moreover, it highlights the potential for AR-HMD to be readily integrated into Level 1 trauma centers without requiring extensive modifications or adjustments.
Sphenoid Sinus Mucosal Flap after Transsphenoidal Surgery—A Systematic Review
Authors: Sumislawski Piotr , Piotrowska Martyna , Regelsberger Jan , Flitsch Jörg , Rotermund Roman
Published: February 2024

Background and Objectives: Skull base reconstruction is a crucial step during transsphenoidal surgery. Sphenoid mucosa is a mucosal membrane located in the sphenoid sinus. Preservation and lateral shifting of sphenoid mucosa as sphenoid mucosal flap (SMF) during the transsphenoidal exposure of the sella may be important for later closure. This is the first systematic review to evaluate the utility of sphenoid mucosal flap for sellar reconstruction after transsphenoidal surgery. Materials and Methods: A systematic literature search was performed in January 2023: Cochrane, EMBASE, PubMed, Scopus, and Web of Science. The following keywords and their combinations were used: “sphenoid mucosa”, “sphenoid sinus mucosa”, “sphenoid mucosal flap”, “sphenoid sinus mucosal flap”. From a total number of 749 records, 10 articles involving 1671 patients were included in our systematic review. Results: Sphenoid sinus mucosa used to be applied for sellar reconstruction as either a vascularized pedicled flap or as a free flap. Three different types of mucosal flaps, an intersinus septal flap, a superiorly based flap and an inferiorly based flap, were described in the literature. Total SMF covering compared to partial or no SMF covering in sellar floor reconstruction resulted in fewer postoperative CSF leaks (p = 0.008) and a shorter duration of the postoperative lumbar drain (p = 0.003), if applied. Total or partial SMF resulted in fewer local complications (p = 0.012), such as fat graft necrosis, bone graft necrosis, sinusitis or fungal infection, in contrast to no SMF implementation. Conclusions: SMF seems to be an effective technique for skull base reconstruction after transsphenoidal surgery, as it can reduce the usage of avascular grafts such as fat along with the incidence of local complications, such as fat graft necrosis, bone graft necrosis, sinusitis and fungal infection, or it may improve the sinonasal quality of life by maintaining favorable wound healing through vascular flap and promote the normalization of the sphenoid sinus posterior wall. Further clinical studies evaluating sphenoid mucosal flap preservation and application in combination with other techniques, particularly for higher-grade CSF leaks, are required.
Effect of a Gradient Temperature Rolling Process on the Microstructure and Mechanical Properties of the Center of Ultra-Heavy Plates
Authors: Cong Jinghua , Zhao Jingxiao , Wang Xuemin , Wu Zhongwen
Published: February 2024

As there is a small amount of deformation in the center during the rolling process of ultra-heavy plates, it is extremely easy to cause poor mechanical properties in the center. Increasing the deformation in the center is the most feasible method to eliminate the deformation effects in the cross-section of ultra-heavy plates. In this study, the gradient temperature rolling (GTR) process is compared with the traditional uniform temperature rolling (UTR) process. It is found that the GTR process can significantly increase the deformation in the center and thereby refine the grains. The room temperature tensile test and instrumented Charpy impact test are used to test the strength at room temperature and impact energy at low temperature. Combined with the obtained impact load/energy displacement curve, the deformation and damage process under impact load are analyzed. The microstructure morphology and impact fracture obtained by different rolling processes in the center are analyzed by experimental methods such as OM, SEM, EBSD, etc. The prior austenite grain (PAG) boundary morphology is analyzed and the densities of grain boundaries are statistically quantified. The results showed that the strength, plasticity, and low-temperature toughness of the GTR process are improved compared to the UTR process, with increased dislocation density in the center microstructure, the density of PAG boundaries, and the density of packet boundaries. The size of the PAG in the center is refined by ~49%, the density of PAG boundaries increased by ~140%, the density of high-angle packet boundaries increased by ~39%, and the density of low-angle packet boundaries increased by ~49%. The crack propagation in the instrumented Charpy impact test of the GTR process showed stable expansion, indicating a ductile fracture compared to the semi-brittle fracture of the UTR process. The densities of PAG boundaries and high-angle packet boundaries are the most important factors affecting the strength and low-temperature toughness.
Thermodynamics of Aluminothermic Processes for Ferrotitanium Alloy Production from Bauxite Residue and Ilmenite
Authors: Sparis Dimitris , Lazou Adamantia , Balomenos Efthymios , Panias Dimitrios
Published: February 2024

Titanium oxide is a major component of bauxite residue (BR) with a high value, but it is often an unwanted element in common BR reuse options such as cement or iron production. Conventional carbothermic reduction smelting of BR produces a slag still containing a large amount of Ti. This study investigates an aluminothermic process for producing an FeTi alloy by combining BR, ilmenite ore, and fluxes. Based on thermodynamic calculations and batch experiments, the amounts of aluminum (reductant) and fluxes were investigated to achieve the optimum alloy production in parallel with a slag that could be further valorized in the cement industry. The mineralogical and chemical analysis of the metallic and slag phase agreed with the thermodynamic calculations. The results obtained by this study can lead to the development of a new process for the complete valorization of BR, paving the way for scaling up aluminothermic processes for producing ferroalloys from all iron-rich residues.
Pilot Tests of Pre-Reduction in Chromium Raw Materials from Donskoy Ore Mining and Processing Plant and Melting of High-Carbon Ferrochromium
Authors: Shabanov Yerbol , Makhambetov Yerbolat , Saulebek Zhalgas , Toleukadyr Ruslan , Baisanov Sailaubai , Nurgali Nurzhan , Shotanov Azamat , Dossekenov Murat , Zhumagaliyev Yerlan
Published: February 2024

Experiments were conducted to pilot the initial reduction in chromium raw materials using the innovative Hoganas technology in a tunnel furnace. To simulate the process, a gas-fired bogie hearth furnace was employed. Technological containers made of silicon carbide crucibles were utilized. Sixteen different combinations of ore and coal mixtures were employed for the initial reduction process. Their total mass was more than 20 tons. Their heat treatment was performed at different temperatures and durations. During the pilot tests, the possibility of achieving chromium metallization was confirmed. Thus, it explains the application of a pre-reduction instead of the sintering or charge heating before the ferrochromium melting, i.e., the power consumption is minimized during the final remelting of the product in DC furnaces. The pilot melting of three batches of the pre-reduced chromium raw materials with various chromium metallization degrees has been tested in the ore-smelting furnace at Zh. Abishev Chemical–Metallurgical Institute (Karaganda). The capacity was 0.2 MVA. To evaluate the technical and economic efficiency of remelting pre-reduced chromium raw materials in commercial DC furnaces, a specific batch of primary ingredients for producing high-carbon ferrochromium, including chromite ore, coke, and quartz flux, was successfully melted in a segregated phase. As a result of the study, it was found that the specific energy consumption for melting high-carbon ferrochromium in the pilot furnace depends on the chromium metallization degree. The researchers tested a range of chromium metallization degrees from 0 to 65% and determined the corresponding specific energy consumption for each degree. Using the data obtained from the study, the researchers were able to assess the melting indexes of high-carbon ferrochromium in a larger 72 MW furnace. They found that by using a pre-reduced product with a chromium metallization degree of 65%, it was possible to reduce the specific energy consumption by half, to around 3.4 MW·h per ton of chromium. Overall, this study highlights the importance of considering the chromium metallization degree when determining the specific energy consumption for melting high-carbon ferrochromium. By optimizing the metallization degree, significant energy savings can be achieved, leading to more efficient and sustainable production processes.
A 2000-Year-Old Bacillus stercoris Strain Sheds Light on the Evolution of Cyclic Antimicrobial Lipopeptide Synthesis
Authors: Chouaia Bessem , Dittmer Jessica
Published: February 2024

Some bacteria (notably the genera Bacillus and Clostridium) have the capacity to form endospores that can survive for millions of years in isolated habitats. The genomes of such ancient bacteria provide unique opportunities to understand bacterial evolution and metabolic capabilities over longer time scales. Herein, we sequenced the genome of a 2000-year-old bacterial strain (Mal05) isolated from intact apple seeds recovered during archaeological excavations of a Roman villa in Italy. Phylogenomic analyses revealed that this strain belongs to the species Bacillus stercoris and that it is placed in an early-branching position compared to most other strains of this species. Similar to other Bacillus species, B. stercoris Mal05 had been previously shown to possess antifungal activity. Its genome encodes all the genes necessary for the biosynthesis of fengycin and surfactin, two cyclic lipopeptides known to play a role in the competition of Bacilli with other microorganisms due to their antimicrobial activity. Comparative genomics and analyses of selective pressure demonstrate that these genes are present in all sequenced B. stercoris strains, despite the fact that they are not under strong purifying selection. Hence, these genes may not be essential for the fitness of these bacteria, but they can still provide a competitive advantage against other microorganisms present in the same environment.
Diversity and Biological Characteristics of Seed-Borne Bacteria of Achnatherum splendens
Authors: Yang Jie , Xie Jinjing , Chen Haiyan , Zhu Shaowei , Hou Xuan , Zhang Zhenfen
Published: February 2024

As a high-quality plant resource for ecological restoration, Achnatherum splendens has strong adaptability and wide distribution. It is a constructive species of alkaline grassland in Northwest China. The close relationship between seed-borne bacteria and seeds causes a specific co-evolutionary effect which can enhance the tolerance of plants under various stresses. In this study, 272 bacterial isolates were isolated from the seeds of Achnatherum splendens in 6 different provinces of China. In total, 41 dominant strains were identified, and their motility, biofilm formation ability and antibiotic resistance were analyzed. The results showed that the bacteria of Achnatherum splendens belonged to 3 phyla and 14 genera, of which Firmicutes was the dominant phylum and Bacillus was the dominant genus. The motility and biofilm formation ability of the isolated strains were studied. It was found that there were six strains with a moving diameter greater than 8 cm. There were 16 strains with strong biofilm formation ability, among which Bacillus with biofilm formation ability was the most common, accounting for 37.5%. The analysis of antibiotic resistance showed that sulfonamides had stronger antibacterial ability to strains. Correlation analysis showed that the resistance of strains to aminoglycosides (kanamycin, amikacin, and gentamicin) was significantly positively correlated with their biofilm formation ability. This study provides fungal resources for improving the tolerance of plants under different stresses. In addition, this is the first report on the biological characteristics of bacteria in Achnatherum splendens.
On the Way to the Technological Development of Newly Selected Non-Saccharomyces Yeasts Selected as Innovative Biocontrol Agents in Table Grapes
Authors: Salerno Antonella , D’Amico Margherita , Bergamini Carlo , Maggiolini Flavia Angela Maria , Vendemia Marco , Prencipe Annalisa , Catacchio Claudia Rita , Ventura Mario , Cardone Maria Francesca , Marsico Antonio Domenico
Published: February 2024

Post-harvest decay of fresh table grapes causes considerable annual production losses. The main fungal agents of decay both in pre- and post-harvest are B. cinerea, Penicillium spp., Aspergillus spp., Alternaria spp., and Cladosporium spp. To date, the use of agrochemicals and SO2 are the main methods to control grape molds in pre- and postharvest, respectively. Significant improvements, however, have already been made in to apply innovative and more environmentally sustainable control strategies, such as Biological Control Agents (BCAs), which can reduce disease severity in both pre- and post-harvest. In this study, 31 new non-Saccharomyces yeast strains, isolated from berries of native Apulian table grape genotypes, were tested for their in vivo effectiveness against grey mold of table grapes, resulting in two St. bacillaris (‘N22_I1’ and ‘S13_I3’), one S. diversa (‘N22_I3’), one A. pullulans (‘OLB_9.1_VL’) and one H. uvarum (‘OLB_9.1_BR’) yeast strains that were marked as efficient and good BCAs. Their mechanisms of action were characterized through in vitro assays, and additional characteristics were evaluated to assess the economic feasibility and viability for future technological employment. Their effectiveness was tested by reducing the working concentration, their antagonistic effect on a wide range of fungal pathogens, their ability to survive in formulations with long shelf life, and their safety to human health.
Seasonality and Genotype Diversity of Human Rhinoviruses during an Eight-Year Period in Slovenia
Authors: Berginc Nataša , Sočan Maja , Prosenc Trilar Katarina , Petrovec Miroslav
Published: February 2024

Due to the high socioeconomic burden of rhinoviruses, the development of prevention and treatment strategies is of high importance. Understanding the epidemiological and clinical features of rhinoviruses is essential in order to address these issues. Our study aimed to define the seasonality and molecular epidemiology of rhinoviruses in Slovenia. Over a period of eight years, a total of 20,425 patients from sentinel primary healthcare settings and sentinel hospitals were examined for a panel of respiratory viruses in the national programme for the surveillance of influenza-like illnesses and acute respiratory infections. The patients were from all age groups and had respiratory infections of various severity. Infection with a rhinovirus was confirmed using an RT-rPCR in 1834 patients, and 1480 rhinoviruses were genotyped. The molecular analysis was linked to demographical and meteorological data. We confirmed the year-round circulation of rhinoviruses with clear seasonal cycles, resulting in two seasonal waves with peaks in spring and autumn. High levels of genotype variability and co-circulation were confirmed between and within seasons and were analysed in terms of patient age, the patient source reflecting disease severity, and meteorological factors. Our study provides missing scientific information on the genotype diversity of rhinoviruses in Slovenia. As most previous investigations focused on exclusive segments of the population, such as children or hospitalised patients, and for shorter study periods, our study, with its design, size and length, contributes complementary aspects and new evidence-based knowledge to the regional and global understanding of rhinovirus seasonality and molecular epidemiology.
Investigating Biomolecules in Deep Eutectic Solvents with Molecular Dynamics Simulations: Current State, Challenges and Future Perspectives
Authors: Bittner Jan Philipp , Smirnova Irina , Jakobtorweihen Sven
Published: February 2024

Deep eutectic solvents (DESs) have recently gained increased attention for their potential in biotechnological applications. DESs are binary mixtures often consisting of a hydrogen bond acceptor and a hydrogen bond donor, which allows for tailoring their properties for particular applications. If produced from sustainable resources, they can provide a greener alternative to many traditional organic solvents for usage in various applications (e.g., as reaction environment, crystallization agent, or storage medium). To navigate this large design space, it is crucial to comprehend the behavior of biomolecules (e.g., enzymes, proteins, cofactors, and DNA) in DESs and the impact of their individual components. Molecular dynamics (MD) simulations offer a powerful tool for understanding thermodynamic and transport processes at the atomic level and offer insights into their fundamental phenomena, which may not be accessible through experiments. While the experimental investigation of DESs for various biotechnological applications is well progressed, a thorough investigation of biomolecules in DESs via MD simulations has only gained popularity in recent years. Within this work, we aim to provide an overview of the current state of modeling biomolecules with MD simulations in DESs and discuss future directions with a focus for optimizing the molecular simulations and increasing our fundamental knowledge.
Exploration of the Dynamic Variations of the Characteristic Constituents and the Degradation Products of Catalpol during the Process of Radix Rehmanniae
Authors: Yang Jingjing , Zhang Lihua , Zhang Mengyue , Yang Mingxuan , Zou Lin , Cui Ying , Yang Jing , Chai Xin , Wang Yuefei
Published: February 2024

Radix Rehmanniae (RR), a famous traditional Chinese medicine (TCM) widely employed in nourishing Yin and invigorating the kidney, has three common processing forms in clinical practice, including fresh Radix Rehmanniae (FRR), raw Radix Rehmanniae (RRR), and processed Radix Rehmanniae (PRR). However, until now, there has been less exploration of the dynamic variations in the characteristic constituents and degradation products of catalpol as a representative iridoid glycoside with the highest content in RR during the process from FRR to PRR. In this study, an ultra-performance liquid chromatography coupled with photodiode array detector (UPLC-PDA) method was successfully established for the simultaneous determination of ten characteristic components to explore their dynamic variations in different processed products of RR. Among them, iridoid glycosides, especially catalpol, exhibited a sharp decrease from RRR to PRR. Then, three degradation products of catalpol were detected under simulated processing conditions (100 °C, pH 4.8 acetate buffer solution), which were isolated and identified as jiofuraldehyde, cataldehyde, and norviburtinal, respectively. Cataldehyde was first reported as a new compound. Moreover, the specificity of norviburtinal in self-made PRR samples was discovered and validated, which was further confirmed by testing in commercially available PRR samples. In conclusion, our study revealed the decrease in iridoid glycosides and the production of new degradation substances during the process from FRR to PRR, which is critical for unveiling the processing mechanism of RR.
Regioselective C(sp2)-C(sp3) Coupling Mediated by Classical and Rollover Cyclometalation
Authors: Manca Lorenzo , Senzacqua Giacomo , Stoccoro Sergio , Zucca Antonio
Published: February 2024

By taking advantage of a sequence of oxidative addition/reductive elimination reactions, Pt(II) cyclometalated derivatives are able to promote a rare C(sp2)-C(sp3) bond coupling, resulting in the production of novel methyl-substituted pyridines and bipyridines. Starting from 6-phenyl-2,2′-bipyridine, the step-by-step full sequence of reactions has been followed, leading to the unprecedented 3-methyl-6-phenyl-2,2′-bipyridine, which was isolated and fully characterized. The synthesis involves the following steps: (1) rollover cyclometalation to give the starting complex [Pt(N^C)(DMSO)Me]; (2) the synthesis of a more electron-rich complex [Pt(N^C)(PPh3)Me] by the substitution of DMSO with triphenylphosphine; (3) oxidative addition with methyl iodide to give the Pt(IV) complex [Pt(N^C)(PPh3)(Me)2(I)]; (4) iodide abstraction with silver tetrafluoborate to give an unstable pentacoordinate intermediate, which rapidly evolves through a carbon–carbon reductive coupling, forming a new C(sp3)-C(sp2) bond; (5) finally, the extrusion and characterization of the newly formed 3-methyl-6-phenyl-2,2′-bipyridine. The reaction has been therefore extended to a well-known classical cyclometalating ligand, 2-phenylpyridine, demonstrating that the method is not restricted to rollover derivatives. Following the same step-by-step procedure, 2-phenylpyridine was converted to 2-o-tolyl-pyridine, displaying the potential application of the method to the larger family of classical cyclometalated complexes. The application of this protocol may be useful to convert an array of heterocyclic compounds to their methyl- or alkyl-substituted analogs.
Correction: Choi et al. Genistin: A Novel Potent Anti-Adipogenic and Anti-Lipogenic Agent. Molecules 2020, 25, 2042
Authors: Choi Yae Rim , Shim Jaewon , Kim Min Jung
Published: February 2024

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Study on the Physical and Rheological Characterisation of Low-Density Polyethylene (LDPE)/Recycled Crumb Rubber (RCR) on Asphalt Binders
Authors: Zhang Shibo , Yan Yong , Yang Yang , Guo Rongxin
Published: February 2024

Recycled crumb rubber (RCR) is considered a reliable asphalt modifier and a solution to the problem of scrap tyre recycling. RCR-modified asphalt (RCRMA) typically has good low-temperature performance and storage stability. However, the pre-treatment of crumb rubber (CR) impairs its physical properties, resulting in poor high-temperature performance, which limits the industrial application of RCRMA. In this study, low-density polyethylene (LDPE) composite RCR was used to modify asphalt, and LDPE/RCR-composite-modified asphalt (L-RCRMA) was produced to compensate for the deficiencies in the high-temperature performance of RCRMA. The comprehensive physical properties of L-RCRMA were elucidated using tests such as the conventional properties, rotational viscosity, and rheological tests. The results showed that the incorporation of LDPE improved the high-temperature stability and rutting resistance of the asphalt, but an excessive amount of LDPE impaired the low-temperature performance and storage stability of L-RCRMA. Therefore, it is necessary to control the amount of LDPE to balance the performance of the asphalt. On this basis, we recommend a dosage of 20% for RCR and 1.5% for LDPE.
Recent Developments in Functional Polymers via the Kabachnik–Fields Reaction: The State of the Art
Authors: Yuan Rui , He Xianzhe , Zhu Chongyu , Tao Lei
Published: February 2024

Recently, multicomponent reactions (MCRs) have attracted much attention in polymer synthesis. As one of the most well-known MCRs, the Kabachnik–Fields (KF) reaction has been widely used in the development of new functional polymers. The KF reaction can efficiently introduce functional groups into polymer structures; thus, polymers prepared via the KF reaction have unique α-aminophosphonates and show important bioactivity, metal chelating abilities, and flame-retardant properties. In this mini-review, we mainly summarize the latest advances in the KF reaction to synthesize functional polymers for the preparation of heavy metal adsorbents, multifunctional hydrogels, flame retardants, and bioimaging probes. We also discuss some emerging applications of functional polymers prepared by means of the KF reaction. Finally, we put forward our perspectives on the further development of the KF reaction in polymer chemistry.
Natural Compounds in Non-Melanoma Skin Cancer: Prevention and Treatment
Authors: Kowalski Szymon , Karska Julia , Tota Maciej , Skinderowicz Katarzyna , Kulbacka Julita , Drąg-Zalesińska Małgorzata
Published: February 2024

The elevated occurrence of non-melanoma skin cancer (NMSC) and the adverse effects associated with available treatments adversely impact the quality of life in multiple dimensions. In connection with this, there is a necessity for alternative approaches characterized by increased tolerance and lower side effects. Natural compounds could be employed due to their safety profile and effectiveness for inflammatory and neoplastic skin diseases. These anti-cancer drugs are often derived from natural sources such as marine, zoonotic, and botanical origins. Natural compounds should exhibit anti-carcinogenic actions through various pathways, influencing apoptosis potentiation, cell proliferation inhibition, and metastasis suppression. This review provides an overview of natural compounds used in cancer chemotherapies, chemoprevention, and promotion of skin regeneration, including polyphenolic compounds, flavonoids, vitamins, alkaloids, terpenoids, isothiocyanates, cannabinoids, carotenoids, and ceramides.
Angelica Sinensis Polysaccharide-Based Nanoparticles for Liver-Targeted Delivery of Oridonin
Authors: Sun Henglai , Nai Jijuan , Deng Biqi , Zheng Zhen , Chen Xuemei , Zhang Chao , Sheng Huagang , Zhu Liqiao
Published: February 2024

The present work aimed to study the feasibility of Angelica sinensis polysaccharide (ASP) as an instinctive liver targeting drug delivery carrier for oridonin (ORI) in the treatment of hepatocellular carcinoma (HCC). ASP was reacted with deoxycholic acid (DOCA) via an esterification reaction to form an ASP-DOCA conjugate. ORI-loaded ASP-DOCA nanoparticles (ORI/ASP-DOCA NPs) were prepared by the thin-film water method, and their size was about 195 nm in aqueous solution. ORI/ASP-DOCA NPs had a drug loading capacity of up to 9.2%. The release of ORI in ORI/ASP-DOCA NPs was pH-dependent, resulting in rapid decomposition and accelerated drug release at acidic pH. ORI/ASP-DOCA NPs significantly enhanced the accumulation of ORI in liver tumors through ASGPR-mediated endocytosis. In vitro results showed that ORI/ASP-DOCA NPs increased cell uptake and apoptosis in HepG2 cells, and in vivo results showed that ORI/ASP-DOCA NPs caused effective tumor suppression in H22 tumor-bearing mice compared with free ORI. In short, ORI/ASP-DOCA NPs might be a simple, feasible, safe and effective ORI nano-drug delivery system that could be used for the targeted delivery and treatment of liver tumors.