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Records with Subject: Biosystems
Comparison of the Limit of Detection of Paracetamol, Propyphenazone, and Caffeine Analyzed Using Thin-Layer Chromatography and High-Performance Thin-Layer Chromatography
August 28, 2024 (v1)
Subject: Biosystems
Keywords: detectability, drug analysis, TLC densitometry
TLC (thin-layer chromatography) and HPTLC (high-performance thin-layer chromatography) in normal (NP) and reversed (RP) phase systems were combined with densitometry to analyze caffeine, propyphenazone, and paracetamol. This work aims to check whether comparable limit of detection (LOD) values can be obtained on TLC and HPTLC plates. Analyses were performed on five (NP) or four (RP) different stationary phases (chromatographic plates), testing, in both cases, three mobile phases. It is shown that by using both TLC and HPTLC plates, it is possible to develop chromatographic conditions that enable the detection of compounds analyzed in amounts ranging from a dozen to several dozen µg/spot. In the RP system, lower LOD values for all tested compounds were obtained using TLC than HPTLC. However, performing analyses in the NP, similar (of the same order) LOD values were obtained for caffeine, propyphenazone, and paracetamol when using both TLC and HPTLC plates. For example, during the NP-HPT... [more]
Editorial on the Special Issue “Natural Compounds Applications in Drug Discovery and Development”
August 28, 2024 (v1)
Subject: Biosystems
Nature is an amazing source of natural bioactive compounds derived from numerous species of plants, marine bacteria, and fungi [...]
Comparison of Tetraselmis suecica Cell Disruption Techniques: Kinetic Study and Extraction of Hydrosoluble Compounds
August 28, 2024 (v1)
Subject: Biosystems
Keywords: Extraction, high-pressure homogenization, kinetics, microalgae, ultrasonication
The optimization of cell disruption is a critical step in microalgal biorefineries. We used the same batch of Tetraselmis suecica culture to compare two mechanical cell disruption techniques, focusing on the extraction yield of water-soluble molecules. The conditions for high-pressure homogenization (HPH) studied were two passes at a moderate pressure of 300 bars. For ultrasound (US) treatment, we used an amplitude of 20% (equivalent to 100 W) for 25 min. These conditions were chosen on the basis of a preliminary screen of extraction conditions. HPH extracted proteins and pigments more efficiently than US, whereas US was superior for uronic acid extraction. Interestingly, the two methods had similar extraction yields for carbohydrates under the studied conditions. We also analyzed the kinetics of molecule release by considering the centrifugation time lag for HPH and applying a first-order kinetic model for US. HPH outperformed US in terms of the immediate extraction and release of mol... [more]
The Effect of Microbial Compound Fertilizer on the Heavy Metal Binding Forms and Enzyme Activity in Soil
August 28, 2024 (v1)
Subject: Biosystems
Keywords: heavy metal binding forms, heavy-metal-polluted soil, microbial compound fertilizer, physicochemical properties, soil enzyme activity
Nowadays, heavy metal pollution in soil caused by human production activities is increasingly serious. The heavy metal ions in soil inhibit plant growth and endanger human health as they can disrupt the physicochemical properties of soil. However, the elimination of heavy metals in soil is so difficult that more and more researchers are studying effective soil conditioners. The negatively charged groups in microbial communities can bind with heavy metal ions in the soil to remove them. In this paper, Cr- and Cd-polluted soils were used to simulate heavy-metal-polluted soil, and microbial compound fertilizer (MOF) was used as a soil conditioner for removing Cr and Cd in soil. The effects of different additive amounts of MOF on the physicochemical properties, the concentration of metal binding forms in soil and the enzyme activity of soil were investigated. The results showed that when the addition amount of fertilizer was 10%, the improvement effect on Cr- and Cd-polluted soils was the... [more]
Bacteriostatic Activity of Janthinobacterium lividum and Purified Violacein Fraction against Clavibacter michiganensis
August 28, 2024 (v1)
Subject: Biosystems
Keywords: adenosine triphosphatase, ATP-ase, bacteriostatic activity, Clavibacter michiganensis, intermicrobial interactions, Janthinobacterium lividum, violacein
causes plant diseases and is included in the list of microorganisms subject to export control. Janthinobacterium lividum is capable of synthesizing a pigment with antagonistic potential. The purpose of the study was to evaluate the activity of J. lividum VKM B-3705D and the pigment fraction against C. michiganensis VKM Ac-1402. The results of spectrophotometric and nuclear magnetic resonance analysis showed that the pigment synthesized by the J. lividum VKM B-3705D corresponds to violacein. The J. lividum strain demonstrated potential bacteriostatic activity against C. michiganensis VKM Ac-1402 when both strains were co-cultured. Compared to the control (DMSO), the violacein solution suppressed the specific growth of Clavibacter by 57.7%. The mechanism of suppression of the growth of Clavibacter is discussed. One of the ways to suppress the growth of C. michiganensis may be the inhibition of key enzymes. Violacein inhibited the activity of adenosine triphosphatase (ATPase, EC 3.6.1.3)... [more]
Organic Waste for Bioelectricity Generation in Microbial Fuel Cells: Effects of Feed Physicochemical Characteristics
August 28, 2024 (v1)
Subject: Biosystems
Keywords: bioelectricity generation, COD removal, feed physicochemical characteristics, microbial fuel cell, organic wastes
Food waste (FW), piggery waste (PW), and activated sludge (AS) were investigated as potential organic feeds for bioelectricity generation in laboratory-scale microbial fuel cells (MFCs). The MFCs fed by FW gained the highest maximum power density at 7.25 W/m3, followed by those fed by PW at 3.86 W/m3 and AS at 1.54 W/m3. The tCOD removal in the FW-, PW-, and AS-MFCs reached 76.9%, 63.9%, and 55.22%, respectively, within a 30-day retention time. Food waste, which resulted in the highest power density and tCOD removal, was selected for a series of following tests to investigate the effects of some physicochemical properties of organic feed on the performance of MFCs. The effect of feed particle size was tested with three controlled size ranges (i.e., 3, 1, and <1 mm) in MFCs. A smaller feed particle size provided a higher power density of 7.25 W/m3 and a tCOD removal of 76.9% compared to the MFCs fed with organic waste with a larger particle size. An increment in feed moisture from 70... [more]
Application of Lactiplantibacillus plantarum LP95 as a Functional Starter Culture in Fermented Tofu Production
August 28, 2024 (v1)
Subject: Biosystems
Keywords: fermented soy product, Lactiplantibacillus plantarum, tofu
Several studies have shown that lactic acid bacteria (LAB) fermentation plays an important role in the development and application of soy-based products and could increase their nutritional values and content of bioactive substances. Lactiplantibacillus plantarum LP95 has shown in previous studies to be a promising candidate as a probiotic and microbial culture in fermented soymilk production. In this study, the suitability of Lp. plantarum LP95 as a functional starter culture in tofu production was verified, with a focus on evaluating the isoflavone and amino acid content in the final product after 21 days of storage at 4 °C. Lp. plantarum LP95 was found able to ferment monosaccharides and disaccharides naturally present in soymilk (D-glucose, D-fructose, D-galactose and D-sucrose) after 24 h while leaving the content of galacto-oligosaccharides (stachyose and raffinose) unaffected. The rich amino acid profile of tofu has undergone some quantitative but not qualitative variations comp... [more]
Novel Hydrazide Hydrazone Derivatives as Antimicrobial Agents: Design, Synthesis, and Molecular Dynamics
August 28, 2024 (v1)
Subject: Biosystems
Keywords: 2-oxopyridine, antimicrobial activity, hydrazide, hydrazone, molecular dynamics, thiazole
Ester 2 was produced by reacting thiourea derivative 1 with ethyl 2-chloro-3-oxobutanoate in MeOH containing piperidine. Hydrazide 3 was produced by reacting the latter ester with hydrazine hydrate in EtOH at reflux. By reacting hydrazide 3 with aromatic/heterocyclic aldehydes, twelve derivatives of hydrazide hydrazone 5a−l were produced. Spectral measurements and elemental analysis verified the molecular structure. Compounds 2, 5a, 5c, 5d, and 5f had strong effects on all the pathogenic bacterial strains according to an evaluation of the antimicrobial qualities of the synthetic compounds. With inhibitory zone diameters ranging from 16 to 20.4 mm, hydrazide hydrazone 5f exhibited the strongest activity. Additionally, the minimum inhibitory concentration (MIC) was assessed. The best outcomes were found with hydrazones 5c and 5f. For B. subtilis, the MIC of 5c was 2.5 mg/mL. For E. coli and K. pneumoniae, the MIC of 5f was 2.5 mg/mL. The molecular mechanics-generalized born surface area... [more]
Optimized Ultrasonic Extraction of Essential Oil from the Biomass of Lippia graveolens Kunth Using Deep Eutectic Solvents and Their Effect on Colletotrichum asianum
August 23, 2024 (v1)
Subject: Biosystems
Keywords: antifungal activity, deep eutectic solvents, essential oils, Lippia graveolens, Mexican oregano, ultrasound-assisted extraction
Essential oils are emerging as alternatives to conventional pest control chemicals. Lippia graveolens Kunth (Mexican oregano) is a source of essential oils and during conventional extraction, the biomass generated is discarded as waste; however, reports show that this biomass is still a rich source of essential oils. Conventional essential oil extraction causes contamination and utilizes toxic solvents. Deep eutectic solvents (DESs) offer low toxicity, biodegradability, high selectivity, and yields comparable to organic solvents. This study obtained essential oil from Lippia graveolens biomass via hydrodistillation with ultrasound-assisted DES pretreatment. This research aimed to optimize the extraction of essential oil from Lippia graveolens biomass using ultrasound-assisted DESs and assess its in vitro and in vivo inhibitory effect on C. asianum. The response variables were extraction yield and total reducing capacity. Optimal conditions were determined using a central composite rota... [more]
10. LAPSE:2024.1865
Matrix-Metalloproteinase-Responsive Brain-Derived Neurotrophic Factor for Spinal Cord Injury Repair
August 23, 2024 (v1)
Subject: Biosystems
Keywords: brain-derived neurotrophic factor (BDNF), matrix metalloproteinases (MMPs), on-demand release, spinal cord injury repair
Brain-derived neurotrophic factor (BDNF) plays a vital role in supporting neuronal survival, differentiation, and promoting synaptogenesis, thereby facilitating synaptic plasticity in the central nervous system. Administration of exogenous BDNF is a crucial approach for treating central nervous system injuries. However, the inability of sustained drug release to match disease activity often leads to insufficient drug accumulation in the injured area (ineffectiveness) and severe side effects induced by the drug (toxicity). Matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9, are typically upregulated after tissue damage, and their upregulated expression levels represent the degree of disease activity. In this study, we utilized bioengineering techniques to prepare a BDNF that can specifically bind to collagen and be released in response to MMP substrate cleavage (collagen binding domain tissue inhibitor of matrix metalloproteinases brain-derived neurotrophic factor, CBD-TIMP-BD... [more]
11. LAPSE:2024.1857
Development and Characterization of a Novel Microwave Plasma Source for Enhanced Healing in Wound Treatment
August 23, 2024 (v1)
Subject: Biosystems
Keywords: argon plasma, cold atmospheric plasma, microwave plasma, microwave plasma, plasma device, tissue regeneration, wound care, wound healing, wound regeneration
Our study explores the potential of a novel microwave plasma source for enhancing wound healing in BALB-C mouse models. Chronic wounds, particularly in diabetic individuals, present significant challenges due to impaired regenerative capacity. Cold Atmospheric Plasma (CAP) has emerged as a promising approach, offering diverse therapeutic benefits. However, its specific efficacy in the context of diabetic wounds remains underexplored. We developed and characterized a microwave plasma source optimized for wound treatment, inducing acute wounds and treating them with CAP in a controlled experimental setup. The treated group exhibited accelerated wound closure compared to controls, suggesting CAP’s potential to enhance the healing process. Our findings underscore CAP’s multifaceted impact on the wound healing cascade, highlighting its ability to promote angiogenesis, modulate inflammatory responses, and exhibit antimicrobial properties. These results position CAP as a promising interventio... [more]
12. LAPSE:2024.1845
A Promising Biocontrol Agent of Bacillus velezensis VC3 against Magnaporthe oryzae and Colletotrichum gloeosporioides in Plants
August 23, 2024 (v1)
Subject: Biosystems
Keywords: antifungal activity, Bacillus velezensis, biocontrol, phytopathogenic fungi, secondary metabolites
Fungal diseases of plants are one of the key factors causing global crop losses. In this study, we isolated a Bacillus velezensis strain VC3, which was found to have a broad-spectrum inhibitory effect on a variety of phytopathogenic fungi through in vitro and in planta experiments, especially on Magnaporthe oryzae and Colletotrichum gloeosporioides. Further genomic and transcriptomic analyses revealed that the B. velezensis VC3 has multiple functional gene clusters encoding for the synthesis of a variety of antifungal secondary metabolites, including antimicrobial peptides (AMPs) and lipopeptides (LPs). In addition, AMPs and LPs were isolated and purified from B. velezensis VC3 fermentation broth and their antifungal activities were verified in this study. AMPs and LPs significantly inhibited spore germination, appressorium formation, and disease development, and AMPs have a better potential for controlling M. oryzae and C. gloeosporioides than LPs. These findings open new avenues for... [more]
13. LAPSE:2024.1826
CMGB-YT Biosurfactant for Treatment of Heavy Metal- and Microbial-Contaminated Wastewater
August 23, 2024 (v1)
Subject: Biosystems
Keywords: biosurfactant, Candida parapsilosis, heavy metals, hydrocarbons, vegetable oils, wastewater treatment
During the last few decades, water pollution has become a growing concern at international level. To date, only a few Candida parapsilosis strains were successfully used in environmental remediation. In the present article, the strain C. parapsilosis CMGB-YT was studied for its ability to assimilate hydrophobic substrates and to produce biosurfactants with antimicrobial activity and positive effects on heavy metal removal from contaminated wastewaters. The strain C. parapsilosis CMGB-YT was grown on yeast peptone (YP) media with 1% n-decane, n-dodecane, n-tetradecane, n-hexadecane, as well as commercial sunflower and olive oils. The production of the biosurfactant was evaluated using the emulsification index (E24%). The surface properties and emulsifying stability of the biosurfactant were determined. The effect of the biosurfactant on the cell growth of two strains of Rhodotorula mucilaginosa and on their removal capacity of lead (0.032 g/L) and cadmium (0.030 g/L) ions from synthetic... [more]
14. LAPSE:2024.1782
RETRACTED: Hasnol et al. A Review on Insights for Green Production of Unconventional Protein and Energy Sources Derived from the Larval Biomass of Black Soldier Fly. Processes 2020, 8, 523
August 23, 2024 (v1)
Subject: Biosystems
The Processes Editorial Office retracts the article titled “A Review on Insights for Green Production of Unconventional Protein and Energy Sources Derived from the Larval Biomass of Black Soldier Fly” [...]
15. LAPSE:2024.1773
Harnessing the Potential of Harpin Proteins: Elicitation Strategies for Enhanced Secondary Metabolite Accumulation in Grapevine Callus Cultures
August 23, 2024 (v1)
Subject: Biosystems
Keywords: callus, harpin proteins, phenolic compounds, secondary metabolite, Vitis vinifera L.
Grapes and grape products are rich in secondary metabolites such as phenolic compounds and anthocyanins, which have antioxidant properties. These compounds possess health-promoting attributes, including cardioprotective, antimicrobial, and anticancer effects. In recent years, biotechnological methods have been employed to produce high quantities and purity of secondary metabolites under in vitro conditions, aiming to elucidate their complex functions and optimize production methods. However, the potential effects of harpin proteins on the accumulation of secondary compounds in callus cultures have not been investigated thus far. Harpin proteins, encoded by the hrp gene clusters in Gram-negative phytopathogens, are known to trigger defense responses in various plant species by promoting the accumulation of secondary compounds. These findings suggest that harpin proteins may have the potential to enhance secondary metabolite accumulation in callus cultures. This study therefore investiga... [more]
16. LAPSE:2024.1761
RETRACTED: Wong et al. In-Situ Yeast Fermentation Medium in Fortifying Protein and Lipid Accumulations in the Harvested Larval Biomass of Black Soldier Fly. Processes 2020, 8, 337
August 23, 2024 (v1)
Subject: Biosystems
The Processes Editorial Office retracts the article titled “RETRACTED: In-Situ Yeast Fermentation Medium in Fortifying Protein and Lipid Accumulations in the Harvested Larval Biomass of Black Soldier Fly” [...]
17. LAPSE:2024.1748
Impact of Spray Drying on the Properties of Grape Pomace Extract Powder
August 23, 2024 (v1)
Subject: Biosystems
Keywords: anthocyanin stability, bioactive compounds, encapsulation, green solvents, maltodextrin, malvidin, powder cohesiveness
Incorporating anthocyanins, valuable natural pigments, into a powder can improve their stability, but exposure to high temperatures during processing can cause them to degrade. The purpose of this study was to investigate how the inlet air temperature during spray drying affects the physical and chemical characteristics as well as the flowability of a grape pomace anthocyanin powder obtained through ultrasound-assisted extraction using acidified water as the solvent. An anthocyanin solution containing 13% (w/v) maltodextrin was subjected to spray drying at temperatures ranging from 120 to 170 °C. Tukey’s test was applied to compare the means of the samples. The samples dried at temperatures between 130 and 170 °C were adequate, with a moisture content < 5% and a water activity < 0.3, indicating that the powder was stable. The highest anthocyanin retention (91.94 ± 1.59%) and process yield (50.00 ± 3.06%) were achieved at 140 °C, while higher temperatures resulted in anthocyanin degr... [more]
18. LAPSE:2024.1716
Microbial Biomass in Mesophilic and Thermophilic High-Rate Biodigestion of Sugarcane Vinasse: Similar in Quantity, Different in Composition
August 23, 2024 (v1)
Subject: Biosystems
Keywords: 16S rRNA gene amplicon sequencing, AnSTBR, biomass growth yield, specific organic loading rate, two-stage biodigestion, vinasse management
This study compared the behavior of the biomass in two fixed-film anaerobic reactors operated under equivalent organic loading rates but at different temperatures, i.e., 30 °C (RMM) and 55 °C (RMT). The reactors were fed with sugarcane vinasse and molasses (both fermented) in a simulation of sequential periods of season and off-season. The dynamics of biomass growth and retention, as well as the microbial composition, were assessed throughout 171 days of continuous operation, coupled with an additional 10-day test assessing the microbial activity in the bed region. Despite the different inoculum sources used (mesophilic granular vs. thermophilic flocculent sludge types), the biomass growth yield was identical (0.036−0.038 g VSS g−1COD) in both systems. The retention rates (higher in RMT) were regulated according to the initial amount of biomass provided in the inoculation, resulting in similar amounts of total retained biomass (46.8 vs. 43.3 g VSS in RMT and RMM) and biomass distributi... [more]
19. LAPSE:2024.1705
Thermostable α-Amylases and Laccases: Paving the Way for Sustainable Industrial Applications
August 23, 2024 (v1)
Subject: Biosystems
Keywords: industrial applications, laccases, thermostable enzymes, α-amylases
The growing demand in industrial and biotechnological settings for more efficient enzymes with enhanced biochemical features, particularly thermostability and thermotolerance, necessitates a timely response. Renowned for their versatility, thermostable enzymes offer significant promise across a range of applications, including agricultural, medicinal, and biotechnological domains. This comprehensive review summarizes the structural attributes, catalytic mechanisms, and connection between structural configuration and functional activity of two major classes of thermostable enzymes: α-amylases and laccases. These enzymes serve as valuable models for understanding the structural foundation behind the thermostability of proteins. By highlighting the commercial importance of thermostable enzymes and the interest these generate among researchers in further optimization and innovation, this article can greatly contribute to ongoing research on thermostable enzymes and aiding industries in opt... [more]
20. LAPSE:2024.1699
Removal of Cefuroxime from Soils Amended with Pine Bark, Mussel Shell and Oak Ash
August 23, 2024 (v1)
Subject: Biosystems
Keywords: Adsorption, antibiotics, byproducts, desorption, soil
The global increase in antibiotics consumption has caused hazardous concentrations of these antimicrobials to be present in soils, mainly due to the spreading of sewage sludge (or manure or slurry) and wastewater, and they could enter the food chain, posing serious risks to the environment and human health. One of these substances of concern is cefuroxime (CFX). To face antibiotics-related environmental pollution, adsorption is one of the most widely used techniques, with cost-effective and environmentally friendly byproducts being of clear interest to retain pollutants and increase the adsorption capacity of soils. In light of this, in this work, three low-cost bioadsorbents (pine bark, oak ash, and mussel shell) were added to different soil samples (at doses of 12 and 48 t/ha) to study their effects on the adsorption of CFX. Specifically, batch experiments were carried out for mixtures of soils and bioadsorbents, adding a range of different antibiotic concentrations at a fixed ionic... [more]
21. LAPSE:2024.1691
Development of a CaCO3 Precipitation Method Using a Peptide and Microwaves Generated by a Magnetron
August 23, 2024 (v1)
Subject: Biosystems
Keywords: CaCO3 mineralization, irradiation direction, magnetron oscillator, microwave, peptide
Microwave applications, such as microwave ovens and mobile phones, are ubiquitous and indispensable in modern society. As the utilization of microwave technology is becoming more widespread, the effects of microwaves on living organisms and physiological processes have received increased attention. This study aimed to investigate the effects of microwaves on calcium carbonate biomineralization as a model biochemical process. A magnetron oscillator was used to generate 2450 MHz microwaves because magnetrons are relatively inexpensive and widespread. We conducted transmission electron microscopy (TEM), atomic force microscopy (AFM), TEM-electron energy-loss spectroscopy (EELS), dynamic light scattering (DLS), and high-performance liquid chromatography (HPLC) measurements to analyze the calcium carbonate precipitates. Our findings showed the formation of string-like precipitates of calcium carbonate upon microwave irradiation from one direction, similar to those obtained using a semicondu... [more]
22. LAPSE:2024.1539
Optimal Design of Antibody Extraction Systems using Protein A Resin with Multicycling
August 16, 2024 (v2)
Subject: Biosystems
Keywords: Antibody Extraction, Dynamic Modelling, Model Reduction, Optimization, Stochastic Optimization
Antibody therapies are important in treating life-threatening ailments such as cancer and autoimmune diseases. Purity of the antibody is essential for successful applications and Protein A selective resin extraction is the standard step for antibody recovery. Unfortunately, such resins can cost up to 30% of the total cost of antibody production. Hence, the optimal design of this purification step becomes a critical factor in downstream processing to minimize the size of the column needed. An accurate predictive model, as a digital twin representing the purification process, is necessary where changes in the flow rates and the inlet concentrations are modeled via the Method of Moments. The system uncertainties are captured by including the stochastic Ito process model of Brownian motion with drift. Pontryagins Maximum Principle under uncertainty is then applied to predict the flowrate control strategy for optimized resin use, column design, and efficient capturing of the antibodies. In... [more]
23. LAPSE:2024.1312
In Silico and In Vitro Analyses of Multiple Terpenes Predict Cryptotanshinone as a Potent Inhibitor of the Omicron Variant of SARS-CoV-2
June 21, 2024 (v1)
Subject: Biosystems
Keywords: COVID-19, Omicron variant, spike protein, terpenes
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant (B.1.1.529) underwent a substantial number of alterations, and the accompanying structural mutations in the spike protein prompted questions about the virus’s propensity to evade the antibody neutralization produced by prior infection or vaccination. New mutations in SARS-CoV-2 have raised serious concerns regarding the effectiveness of drugs and vaccines against the virus; thus, identifying and developing potent antiviral medications is crucial to combat viral infections. In the present study, we conducted a detailed in silico investigation that involves molecular docking, density functional (DFT) analysis, molecular dynamics (MD) simulations, and pharmacological analysis followed by an in vitro study with the spike protein. Among fifty terpenes screened, cryptotanshinone and saikosaponin B2 were found to be potent S1-RBD spike protein inhibitors, displaying considerable hydrogen bond interactions with ke... [more]
24. LAPSE:2024.1296
Transition Metal Complexes with Amino Acids, Peptides and Carbohydrates in Catalytic Asymmetric Synthesis: A Short Review
June 21, 2024 (v1)
Subject: Biosystems
Keywords: amino acid, asymmetric synthesis, carbohydrate, Catalysis, ligand, modified, organic catalytic synthesis, transition metal complex
The present review is devoted to the application of transition metal complexes with such ligands as amino acids, peptides and carbohydrates in catalysis. The literature published over the past 20 years is surveyed. Among the distinctive features of these ligands are their versatility, optical activity, stability and availability. Furthermore, depending on the specific synthetic task to be solved, these ligands open up almost infinite opportunity for modification. Largely thanks to their multifaceted reactivity, transition metal complexes with amino acids, peptides and carbohydrates can catalyze most of the known chemical reactions affording optically pure compounds. In this review, the emphasis is placed upon C(sp3)−H activation, cross-coupling and hydrogenation (including traditional hydrogenation in the presence of hydrogen gas and hydrogenation with hydrogen transfer) reactions. The choice is not accidental, since these reactions on the one hand display the catalytic versatility of... [more]
25. LAPSE:2024.1292
Improving the Quality of Tantalum Cylindrical Deep-Drawn Part Formation Using Different Lubricating Media-Coated Dies
June 21, 2024 (v1)
Subject: Biosystems
Keywords: DLC, limit drawing ratio, lubrication media, surface topography quality, tantalum metal
Lubrication is one of the key factors to improve metal-forming quality. In the process of deep drawing, seizing tumors easily occur on the contact surfaces between the tantalum metal and the mold, which greatly affects the forming quality of the deep-drawn parts. Quality-forming quality problems that occur during the deep drawing of tantalum metal are studied from the perspective of lubrication in this paper. Three lubrication media, caster oil, PE (polyethylene) film, and DLC (Diamond Like Carbon) film, were adopted in the deep drawing of tantalum cylindrical cups. A universal testing machine and microscope were used to investigate the effect of lubrication media on the limit-drawing ratio, maximum forming force, and surface topography quality during the deep drawing process of the tantalum sheet. The results reveal that the lubrication of the PE film and DLC film can greatly improve the forming quality of the tantalum metal sheet, in which the DLC film has higher wear resistance and... [more]