Shaker Speed Research Articles

B-021 Impact of Assay Conditions on FT4 Measurement Accuracy of Equilibrium Dialysis LC/MS/MS Clinical Assay

Abstract Background Reliable FT4 measurements are vital for accurate diagnosis and effective management of thyroid disorders. However, currently used FT4 immunoassays (IAs) lack standardization, leading to significant variations between platforms. Equilibrium dialysis (ED) coupled with LC-MS/MS analysis, considered the gold standard for FT4 measurement, has been adopted as a reference measurement procedure (RMP) for IA standardization. This study aimed to establish a high-throughput version of the routine clinical FT4 assay based on ED-LC/MS/MS technology and assess the impact of altered assay conditions on measurement accuracy. Methods A commercially available micro-ED plate was employed for ED-LC/MS/MS analysis. FT4 extraction from the dialysate was performed by utilizing a 96-well C18 SPE plate, followed by FT4 quantitation via LC-MS/MS in positive ion mode. Certified primary reference material was used to calibrate the assay. To evaluate assay robustness, the effects of minor method modifications were studied, including incubation time of ED, serum/buffer ratios in ED inserts, ED incubation temperature, shaker speed during ED, serum sample dilution ratio, and dialysate sample dilution ratio. Additionally, short-term and long-term stability of serum FT4 were assessed. Results The developed ED-LC/MS/MS assay successfully resolved T4, T3, reverse triiodothyronine (rT3), and other interferences within 4 minutes using C18 chromatography. The assay's linear range (0.5-100 pg/mL) encompassed clinically relevant FT4 concentrations across hypo- and hyperthyroid patient samples. Excellent agreement was observed between the routine assay based on ED-LC/MS/MS and CDC RMP with a Deming regression slope near 1 (95%CI: 0.87-1.06). Furthermore, serum/buffer ratios from 1:1 to 1:2.5 in ED inserts, shaker speeds from 75 to 150 rpm, and ED incubation times from 16 to 20 hours did not significantly affect FT4 measurement. However, elevated ED temperature (38°C) led to a more than 10% increase in FT4 values. Serum FT4 remained stable when exposed to room temperature for 12 hours, five freeze-thaw cycles, and -70°C storage for 1.5 years. Additionally, dilution of sera by up to 3-fold before ED did not alter FT4 measurement results. Diluting dialysate samples at least 3 times prior to SPE extraction proved accurate for samples exceeding the calibration curve range. Conclusions In conclusion, we successfully developed a routine clinical FT4 assay based on ED-LC/MS/MS that generates data comparable to the RMP. The assay exhibits robustness, with several altered conditions not significantly impacting measurement accuracy. This high-throughput and accurate assay demonstrates suitability for both clinical laboratories and large-scale epidemiological studies. Disclaimer: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the official position of the Centers for Disease Control and Prevention/the Agency for Toxic Substances and Disease Registry. Use of trade names is for identification only and does not imply endorsement by the Centers for Disease Control and Prevention, the Public Health Service, and the US Department of Health and Human Services.

An Investigation of Lanthanum Recovery from an Aqueous Solution by Adsorption (Ion Exchange)

Lanthanum (La(III)) is one of the high-demand rare earth elements with applications in various products. However, La(III) in mining waste streams and electronic waste also poses environmental and health concerns. Therefore, the recovery of La(III) in the waste is needed. In the present study, the adsorption of La(III) with Dowex 50W-X8, Amberchrom50WX4, Amberlyst 15, and Amberchrom 50WX2 was evaluated using a shaker water bath. Dowex 50W-X8 was found to be the best adsorbent and was used to investigate the effect of the shaker speed (RPM = 50–150), adsorbent dosage (1.0–4.0 g), pH (2.0–7.0), and temperature (20–40 °C) on adsorption. La(III) adsorption was found to increase with the shaker speed, as expected. On the other hand, the adsorption capacity decreased with the adsorbent amount. Also, the highest La(III) adsorption was observed at pH = 6.0. La(III) percentage removal did not vary significantly with a temperature from 20 °C to 40 °C. However, the first-order kinetic rate constant decreased moderately with increases in temperature. The adsorption of La(III) by Dowex 50-X8 followed the Freundlich isotherm model better than the Langmuir model. In addition, the adsorption kinetics were represented well by the pseudo-first-order kinetic model. Moreover, enthalpy and Gibbs free energy changes were found to be negative, indicating an exothermic and thermodynamically favorable adsorption process.

A practical approach to demonstrate the circular economy in remediation of textile dyes using nutraceutical industrial spent.

We used Nutraceutical Industrial Coriander Seed Spent (NICSS), a readily available, cheap, eco-friendly, and ready-to-use material, as an innovative adsorbent for the bioremediation of a bisazo Acid Red 119 (AR 119) dye, which is likely a mutagen from textile industrial effluents (TIE). A laboratory-scale experiment was tailored to demonstrate the framework of the circular economy (CE) in the remediation of textile dyes using Nutraceutical Industrial Spent to align with the principles of sustainability and valorization. An experimental q e value of 97.00 mg g-1 was obtained. For the practicality and effectiveness of the method, a two-level fractional factorial experimental design (FFED) was employed to determine variables that influence the adsorption capacity of NICSS. At optimal settings (pH of 1.4, adsorbent dosage of 6.000 g L-1, adsorbent particle size of 96 μm, initial dye concentration of 599 mg L-1, adsorption duration of 173 min, orbital shaking speed of 165 rpm, and temperature of 35 °C), the maximum adsorption efficiency achieved through statistical optimization was 614 mg g-1. Six factors influencing the adsorption process were examined experimentally and were considered important for commercialization. Three orders of magnitude were applied to the identified variables in scaling experiments. Adsorption-equilibrium data were analyzed using nine isotherm models. The best fit was discovered to be the Vieth-Sladek adsorption isotherm model. The suitable mechanism for the overall rate of the adsorption process was a pseudo-second-order reaction: mass-transfer mechanistic studies were predicted to predominate over the diffusion process. NICSS was characterized using SEM and FTIR spectroscopy. Utilizing plastic trash, the dye-adsorbed NICSS that was recovered as "sludge" was utilized as a reinforcing material to create composites. Dye-adsorbed NICSS thermoplastic and thermoset composites were studied and compared with NICSS composites in terms of their physicomechanical and chemical properties.

Optimization of Phycocyanobilin Synthesis in E. coli BL21: Biotechnological Insights and Challenges for Scalable Production.

Phycocyanobilin (PCB) is a small chromophore found in certain phycobiliproteins, such as phycocyanins (PCs) and allophycocyanins (APCs). PCB, along with other phycobilins (PBs) and intermediates such as biliverdin (BV) or phycoerythrobilin (PEB), is attracting increasing biotechnological interest due to its fluorescent and medicinal properties that allow potential applications in biomedicine and the food industry. This study aims to optimize PCB synthesis in Escherichia coli BL21 (DE3) and scale the process to a pre-industrial level. Parameters such as optimal temperature, inducer concentration, initial OD600, and stirring speed were analyzed in shake flask cultures to maximize PCB production. The best results were obtained at a temperature of 28 °C, an IPTG concentration of 0.1 mM, an initial OD600 of 0.5, and an orbital shaking speed of 260 rpm. Furthermore, the optimized protocol was scaled up into a 2 L bioreactor batch, achieving a maximum PCB concentration of 3.8 mg/L. Analysis of the results revealed that biosynthesis of exogenous PBs in Escherichia coli BL21 (DE3) is highly dependent on the metabolic burden of the host. Several scenarios, such as too rapid growth, high inducer concentration, or mechanical stress, can advance entry into the stationary phase. That progressively halts pigment synthesis, leading, in some cases, to its excretion into the growth media and ultimately triggering rapid degradation by the host. These conclusions provide a promising protocol for scalable PCB production and highlight the main biotechnological challenges to increase the yields of the process.

The Liquid-Fermentation Formulation of Sanghuangporus sanghuang Optimized by Response Surface Methodology and Evaluation of Biological Activity of Extracellular Polysaccharides.

Sanghuangporus sanghuang is a rare fungus growing on mulberry trees that has immense medicinal value. This study aimed to optimize the liquid-fermentation-media formulation and culture conditions for large-scale culturing of S. sanghuang by performing one-way testing and response surface methodology. The antioxidant and anticancer activities of the extracellular polysaccharides from S. sanghuang were also analyzed. The optimal formulation and growth conditions for S. sanghuang were as follows: glucose, 30.2 ± 0.37 g/L; yeast extract, 14.60 ± 0.05 g/L; dandelion powder, 1.24 ± 0.01 g/L; shaker speed, 150 r/min; and temperature, 25 °C. We obtained 13.99 ± 0.42 g/L of mycelium biomass by culturing S. sanghuang for 15 days with the optimized formulation. This was 2-fold higher than the mycelial mass obtained with the sub-optimal formulation. The extracellular fungal polysaccharides showed significant antioxidant activity against ABTS and DPPH free radicals, and significantly reduced the in vitro growth and survival of several cancer cell lines. The anticancer activity of the extracellular fungal polysaccharides was significantly higher in the human glioma cells than in other cancer cell lines. In summary, this study optimized the liquid media formulation and conditions for the large-scale culturing of S. sanghuang. Furthermore, the extracellular polysaccharides from S. sanghuang showed significant antioxidant and anticancer activities.

Optimization Time for Antibacterial Production of Endophytic Fungi Isolated from Bidara Root (Ziziphus mauritiana Lam.)

Research on optimization time for antibacterial production of endophytic fungal isolated from bidara root (Ziziphus mauritiana Lam.) has been conducted, with the aim of determining the optimum production time for antibacterial compounds. Endophytic fungi are a group of fungi that live within plant tissues without causing harm to their host plants. In this research, the roots of bidara were isolated and purified using PDA media, isolates were followed by screening endophytic fungi isolates against test bacteria. The results of the endophytic fungal isolation from the bidara roots yielded 10 endophytic fungal isolates. The screening test against the test bacteria showed the largest inhibitory zone for IFAZ-6. Subsequently, the growth curve of these isolates was determined through fermentation using MYB media using a shaker speed of 200 rpm at a temperature of 25-28°C for 27 days. Then, mycelia and supernatant were collected on days 11, 13, 15, 17, 19, 21, 23, 25, and 27 with a 48-hour interval. The mycelia were weighed until a constant weight was obtained, while the supernatant was used to test the activity against the test bacteria using MHA media. The growth curve results indicated a stationary phase on day 21. The antibacterial activity test showed that Isolate IFAZ-6 reached optimum activity on day 27 with an inhibitory zone of 12.33 mm against Salmonella thypi.

Comparison of raw accelerometry data from ActiGraph, Apple Watch, Garmin, and Fitbit using a mechanical shaker table.

The purpose of this study was to evaluate the reliability and validity of the raw accelerometry output from research-grade and consumer wearable devices compared to accelerations produced by a mechanical shaker table. Raw accelerometry data from a total of 40 devices (i.e., n = 10 ActiGraph wGT3X-BT, n = 10 Apple Watch Series 7, n = 10 Garmin Vivoactive 4S, and n = 10 Fitbit Sense) were compared to reference accelerations produced by an orbital shaker table at speeds ranging from 0.6 Hz (4.4 milligravity-mg) to 3.2 Hz (124.7mg). Two-way random effects absolute intraclass correlation coefficients (ICC) tested inter-device reliability. Pearson product moment, Lin's concordance correlation coefficient (CCC), absolute error, mean bias, and equivalence testing were calculated to assess the validity between the raw estimates from the devices and the reference metric. Estimates from Apple, ActiGraph, Garmin, and Fitbit were reliable, with ICCs = 0.99, 0.97, 0.88, and 0.88, respectively. Estimates from ActiGraph, Apple, and Fitbit devices exhibited excellent concordance with the reference CCCs = 0.88, 0.83, and 0.85, respectively, while estimates from Garmin exhibited moderate concordance CCC = 0.59 based on the mean aggregation method. ActiGraph, Apple, and Fitbit produced similar absolute errors = 16.9mg, 21.6mg, and 22.0mg, respectively, while Garmin produced higher absolute error = 32.5mg compared to the reference. ActiGraph produced the lowest mean bias 0.0mg (95%CI = -40.0, 41.0). Equivalence testing revealed raw accelerometry data from all devices were not statistically significantly within the equivalence bounds of the shaker speed. Findings from this study provide evidence that raw accelerometry data from Apple, Garmin, and Fitbit devices can be used to reliably estimate movement; however, no estimates were statistically significantly equivalent to the reference. Future studies could explore device-agnostic and harmonization methods for estimating physical activity using the raw accelerometry signals from the consumer wearables studied herein.

Production of Lipopeptides from Bacillus velezensis BVQ121 and Their Application in Chitosan Antibacterial Coating.

The extracellular substance of Bacillus has antibacterial effects inhibiting multiple foodborne pathogens and plays important roles in food production. This study found one Bacillus velezensis BVQ121 strain producing antibacterial lipopeptides (BVAL). After optimization of the fermentation conditions, the BVAL yield was the highest at 1.316 ± 0.03 g/L in reality with the initial pH 6.0, temperature 31 °C, and shaker speed 238 rpm when the optimal nitrogen and carbon sources were used in Landy medium for fermentation. The antibacterial components were identified as iturin, surfactin, and fengycin by HPLC and MALDI-TOF-MS. The MIC was at 2 mg/mL and MBC was at 5 mg/mL. The 6% weight ratio of nanocellulose dosage in chitosan solution could improve the tensile length and strength of the film, and the antibacterial performance was enhanced by the addition of BVAL. The addition of BVAL had no effect on the color and ductility of the film and improved its antibacterial effect. The shelf life of pigeon eggs can be extended by more than 10 days to resist bacterial infections after coating with the chitosan-nanocellulose-BVAL film solution.

Screening of a novel and thermostable nicotinate dehydrogenase-producing strain Bacillus paramycoides for efficient synthesis of 6-hydroxynicotinic acid

6-Hydroxynicotinic acid emerged as a pivotal intermediate for fine chemicals. The current study aims to screen novel nicotinate dehydrogenase-producing strains. Based on the high-throughput UV coloration method, a novel nicotinate dehydrogenase-producing strain named Bacillus paramycoides was first and successfully screened from soil and gram staining as 16S rRNA gene sequencing was conducted to further confirm its accuracy. The fermentation medium formula is determined as seignette salt (5 g/L), tryptone (10 g/L), K2HPO4 (2 g/L), and nicotinic acid (4 g/L) after a single factor and orthogonal test. The activity of nicotinate dehydrogenase produced by B. paramycoides after optimization reached 1.23 U/mL, which was the highest ever reported. In addition, the enzyme characterization results revealed that the optimum reaction temperature and pH were 40 °C and 7.0, respectively. Furthermore, B. paramycoides nicotinate dehydrogenase exhibited good thermostability with more than 50% of the highest enzyme activity retained at 50 °C after 8 h incubation, which was better than ever reported. The pH stability results suggested that nicotinate dehydrogenase possessed a narrow pH ranging from 6.0 to 8.0. In addition, shaker speed demonstrated a positive relation with enzyme activity since shaker speed could affect mass transfer and dissolved oxygen concentration. Finally, it could completely transform nicotinic acid to 6-HNA within 3 h when the substrate loading is 15 g/L. In conclusion, these results indicated that B. paramycoides nicotinate dehydrogenase could serve as a potential candidate for bioproduction of 6-HNA.

Optimization of polydopamine coating process for poly lactic acid‐based 3D printed bone plates using machine learning approaches

AbstractThe three‐dimensional (3D) printed poly lactic acid (PLA) bone plates lack mechanical strength, resulting in premature failure. Coating these plates with polydopamine (PDM) forms covalent bonds with the PLA molecular structure, enhancing their mechanical properties. The mechanical strength of the coated bone plates is influenced by infill density, submersion time, shaker speed, and coating solution concentration. However, conducting experiments for each parameter value to achieve maximum biomechanical tensile strength (BTS) and biomechanical flexural strength (BFS) is time‐consuming and costly. Overall, the combination of response surface methodology (RSM) and machine learning (ML) enables determination of the best printing parameters, leading to reduced material waste, personalized bone plates tailored to individual anatomy, improved implant fit, and functionality. Moreover, this approach has the potential to reduce the need for additional surgeries and overall costs. To optimize coating parameters, this study employs RSM and ML techniques, including genetic algorithm (GA), particle swarm optimization (PSO), random search optimization (RSO), and differential evolution (DE). Experimental validation of the optimized process parameters and their corresponding fitness values is carried out using both RSM and ML approaches. The results demonstrate that GA has the closest relationship between experimental and fitness values, followed by DE, RSM, PSO, and RSO.Highlights Direct immersion coating of polydopamine on 3D printed PLA bone plates. Evaluating mechanical strength for bone plates coated at varying parameters. Statistical modeling and optimization of mechanical strength using RSM. Mechanical strength optimization and convergence properties for ML models. Experimental validation of RSM and ML‐based optimization algorithms.

Bioleaching of chalcopyrite using native Acidithiobacillus ferrooxidans isolated in a mining area in Kitwe Zambia

This study aimed to assess the influence of the physical-chemical factors (particle size, shake flask speed, starting pH, and pulp density) in bioleaching of Zambian chalcopyrite using a novel native isolated Acidithiobacillus ferrooxidans strain DJN1 2021 from samples collected within mining area at Copper Nkana slag dump also known as the Black Mountain in Kitwe, Copperbelt Province in Zambia. The bacterium isolation was done using the modified 9 K selective media and was identified as A. ferrooxidans by using conventional procedures and 16S rRNA gene sequencing. The resulting sequences were analyzed by trimming and generating consensus sequences using Bio-edit software. Blasting results produced a significant alignment of 99.6% similarity with the corresponding sequences of A. ferrooxidans in GenBank. The phylogenetic analysis entails that the isolated strain was identified as A. ferrooxidans and named A. ferrooxidans strain DJN1 2021 with accession number MZ713091. Bioleaching of chalcopyrite (CuFeS2) by A. ferrooxidans (DJN1 2021) was conducted in shake flasks (100 ml) with a 9 K medium. The experiments were tested to optimize the initial pH, particle size, pulp density, and shake flask speed in the recovery of copper from its ore. The results revealed that all of the factors significantly influence the bioleaching process. When the initial pH was 1.8, copper was extracted at the rate of 30.6% within 30 bioleaching days. This was the maximum dissolution observed. The effect of revolution speed in the three different shake flask speeds (i.e. 50 rpm, 90 rpm, and 150 rpm) showed a significant difference in the rate of copper dissolution. A marked difference was observed between shake flask speeds of 50 rpm and 90 rpm with dissolutions of 29.4% and 30.0% respectively. In experiments to look into the effect of particle size, two size fractions were subjected to bioleaching on a shake flask, i.e. (<45 and 45-<63) µm. Results showed that the (45-<63) µm size fraction gave the highest copper extraction of 29.2%. A pulp density of 6% produced the highest extraction of 32.6%. These findings reveal that this novel native A. ferrooxidans strain DJN1 2021 has the potential to bioleaching of copper from chalcopyrite upon optimization in a bioreactor.

Optimization of Physical Parameters Involved in Cell Lysis of Bacillus Sp. to Recover Bioplastic Polyhydroxyalkanoates

The increased global population has concurrently increased waste disposal, whose majority is conventional plastic. In this study, polyhydroxyalkanoates (PHA), an alternative biopolymer to conventional plastics, were extracted from bacteria Bacillus sp., using response surface methodology (RSM), a statistical approach. To design, optimize and study the relationship between the parameters (glass beads weight, incubation time, water volume, incubation temperature, and shaker speed) Box-Behnken Design of response surface methodology was applied in Design Expert 10.0 software package. The solvent method is known in PHA extraction; however, this approach is environmentally hazardous on a large scale. The current study used a physical extraction method using glass beads for bacterial cell lysis. As a characterization, FTIR, 1HNMR, and DSC confirmed the recovered polymer as Polyhydroxy butyrate (PHB). 31.53% (w/v) of PHB was recovered for 1 g/L biomass. PHB is known to be widely applied in various fields, specifically in medical applications. Genetically modified isolate, low-cost substrate, and recovery without solvent assure a cost-effective and increased PHA production. Glass beads can be reused in extraction, reducing overall production cost. Therefore, this work used a reduced amount of chemicals during extraction to recover the PHB. Thus, sustainability assures a better scope for the future promotion of PHA production in academia and industries.HighlightsSustainable PHA extraction alternatives, reducing environmental impact, were studied.Glass beads are used to lyse the cell to release the PHA from the bacteria Bacillus sp.Box-Behnken design optimized extraction parameters for maximum recovery of PHA.The cellular lysis approach yields higher recovery than solvent-method recovery and is eco-friendly.Graphical abstract

Sorption Kinects and Equilibrium for The Removal of Cadmium and Lead from Aqueous Phase on Rice Husk in Inverse Fluidization Technique

The objectives of this study are to use the inverse fluidization technique to remove heavy metals from wastewater using inexpensive agricultural waste (Rice Husks) and to investigate the effects of operating factors on the dynamic behavior of the adsorption procedure in the inverse fluidized bed, such as the mass of modified rice husks, flow rate (Q), and particle size (dp ). During batch experiments, the best metal ion removal effectiveness was found to be at pH 5, which was discovered after investigating several pH values to achieve this goal. The ideal shaking speed for batch adsorption was 180 rpm. Adsorption efficiency was seen to rise as contact time in the process increased, and the ideal contact time was 3 hours. According to the findings, Cd and Pb had high removal efficiencies from aqueous solutions, 96.83 percent and 91.90%, respectively. Continuous column experiments (inverse fluidized bed) were used to confirm the adsorbent loading capacities for cadmium and lead, which were evaluated by batch research. The proposed adsorbent’s highest adsorption capacity in a batch system was determined to be 7.38 mg/g for Cd and 6.93 mg/g for Pb. Three models-Temkin, Freundlich, and Langmuir-were fitted to a series of equilibrium isothermal tests. The Freundlich isotherm model, with correlation coefficients R2 of 0.98 for Pb and 0.97 for Cd, offered the best fit to the experimental data for this system. The rice husk equilibrium isotherms were determined to be of a favorite kind. To investigate the impact of initial concentrations, bed depth, flow rate, and particle size at a temperature of 30 on the effectiveness of the adsorption process, numerous experiments were conducted in an inverse fluidized bed column. According to the results, rice husk appears to be a material that shows promise for cleaning wastewater of contaminants and toxins.

Green Copper Carbonate Nanoparticles Produced by the Ureolytic Fungus Alternaria sp. Strain ccf7 and Their Antibacterial Activity

Background: Copper carbonate nanoparticles have several applications in the fields of pigments, insecticides, and fungicides. They are also used as catalysts in chemical processes and crude oil desulfurization. Fungi can biosynthesize metal nanoparticles due to their high tolerance, extracellular synthesis, simplicity of extraction, and large-scale exploitation. Objectives: This study aimed to investigate the potential of fungal isolates (which are resistant to copper chloride with urease activity) as biocatalysts for the synthesis of copper carbonate nanoparticles. This approach was considered due to the advantages of using fungal isolates in nanoparticle biosynthesis. Methods: In a PDA culture medium with 25 mM copper chloride, an enrichment culture was used to isolate copper-resistant fungal isolates. Fungal isolates’ urease enzyme was qualitatively assessed using 2% urea agar-based culture media. Studies on the synthesis of copper carbonate nanoparticles and the effect of different parameters on the synthesis of these nanoparticles were conducted using a mycelium-free supernatant strategy. Field emission scanning electron microscope (FESEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) studies were used to determine the properties of calcium carbonate nanoparticles. The selected fungal isolate was identified using macroscopic and microscopic characteristics, as well as molecular analysis using amplification of the ITS1-5.8S-ITS2 gene sequences. Results: Alternaria sp. strain ccf7 (GenBank accession number OP242500) was chosen as the superior strain for copper carbonate nanoparticle synthesis tests based on the pattern of resistance to copper chloride salt and the qualitative assessment of urease activity. Based on the findings of the electron microscope studies, spherical copper carbonate nanoparticles with an average size of 66.7 nm were synthesized after 24 hours of incubation at the optimal concentration of 45 mM copper chloride, temperature of 25°C, and shaker speed of 100 rpm. The distribution of the produced nanoparticles was appropriate, as indicated by a polydispersity index (PDI) of 0.25. The strongest inhibitory impact of these copper carbonate nanoparticles was against Pseudomonas aeruginosa, with an average inhibition of 31 mm at a concentration of 50 mg/L, according to the results of their antibacterial activities. Conclusions: For the first time, the synthesis and development of a green approach for the fabrication of copper carbonate nanoparticles using the genus Alternaria have been proposed in this study.

Predicting biomechanical properties of additively manufactured polydopamine coated poly lactic acid bone plates using deep learning

Fused Filament Fabrication based bone plates lack mechanical strength, resulting in premature failure. Biocompatible Polydopamine (PDM) coating forms covalent bonds with Poly Lactic Acid (PLA), resulting in enhanced mechanical characteristics. Infill density, submersion time, shaker speed, and coating solution concentration, have a significant effect on the mechanical properties of coated bone plates. Monitoring the mechanical strength experimentally for each set of process parameters is a time-consuming and tedious procedure. Before resorting to experimental tests, it is important to model and predict the mechanical strength in order to increase the mechanical strength of bone plates. Predictive modeling using machine learning approaches has proven to be the best alternative to traditional statistical tools. In this study, various machine learning algorithms, including Random Forest, k-Nearest Neighbors, AdaBoost, and Decision Trees, and Long Short-Term Memory (LSTM) method, were utilized to predict tensile and flexural strengths. Error metrics consisting of Mean Square Error (MSE), Root Mean Square Error (RMSE), Correlation Coefficient (R2), Mean Absolute Percentage Error (MAPE) and RRMSE (Root Relative Mean Squared Error) have been utilized to assess the performance of various models. Owing to the prediction findings, the LSTM model beat all ML-based models by demonstrating the best MSE, RMSE, and R2 values for tensile and flexural strength, which were 5.96 MPa, 2.44 MPa, and 0.9169, respectively, and 11.14 MPa, 3.34 MPa, and 0.9242, respectively. Consequently, the results of this study suggest that LSTM is the best model for predicting the tensile and flexural strength of PDM-coated PLA bone plates without doing experiments.

Biomineralization of coral sand by Bacillus thuringiensis isolated from a travertine cave

Travertine is a typical product of microbial mineralization in the nature and its mineral composition is mainly calcite and aragonite. In this paper, Bacillus thuringiensis, a kind of mineralize bacterium is extracted from the travertine crystal to cenment coral sand, and the reinforcement effect of microbial induced carbonate precipitation (MICP) technology on coral sand under different cementation times is studied. Firstly, the culture conditions are optimized in nine pairs of trials, including urea content, microbial inoculation, shaker speed and incubation time. Under the optimal culture conditions, the coral sand is cemented by soaking method. With the increase of reinforcement times, the permeability coefficient of the sand sample is reduced to 10−4 cm/s, and the shear strength is increased by more than 130%. Compared with Sporosarcina pasteurii, the cohesion and internal friction angle of the coral sand column cemented by Bacillus thuringiensis are increased by more than 50% and 10%, respectively. The area distribution of T2 spectrum shows that with the increase of the number of cementation, the amplitude of the main peak decreases, indicating that the large pores are better filled, the number of medium and small pores are also reduced, and the pore area is significantly reduced, with the amplitude of about 44%. The above experiments verified that microorganism in travertine could also be used in MICP technology, and even achieve better reinforcement effect. It also provides a new way and idea for the selection of mineralized bacteria by MICP technology.

Advancement in biological and mechanical behavior of 3D printed poly lactic acid bone plates using polydopamine coating: Innovation for healthcare

The metallic biomaterials have been proclaimed to exhibit stress shielding with discharge of toxic ions, leading to polymeric implants attracting interest in 3D Printing domain. In this study, Poly Lactic Acid based 336 bone plates are fabricated using Fused Filament Fabrication with printing parameters being varied. Polydopamine, being biocompatible, is deposited on fabricated bone plates at varying submersion time, shaker speed and coating solutions concentration. The study involves witnessing the effect of printing and coating parameters on biological behavior of bone plates upon preservation in Simulated Body Fluid and Hank's Balanced Salt Solution. The findings propose the close relation of degradation with apatite growth. The highest degradation rate with significant reduction in mechanical characteristics are shown by uncoated bone plates. These bone plates have porous structure at 20% infill density, 0.5 mm layer height, 0.4 mm wall thickness and 100 mm/s print speed which could result in complete degradation with partial healing of bone fracture. The study suggests the preservation of bone plates coated at 120 h' submersion time and 120 RPM shaker speed in 3 mg/ml concentrated solution which showed lower apatite formation. Thus, the coating would slow down degradation of PLA bone plates, resulting in complete healing of bone fracture.

Isolation, identification and optimization of exopolysaccharide-based bioflocculant synthesis by soil bacteria Bacillus atrophaeus NR-12

Bioflocculants are polysaccharide-based, biodegradable macromolecules synthesized by soil microorganisms. A bacterium prodicing an extracellular bioflocculant wasisolated from the salty and dry soil and identified as Bacillus atrophaeus. Effects of culture conditions including carbon sources, nitrogen sources, pH, shaker speed on bioflocculant production were studied. Isolate comparative analysis of 16S rRNA sequence identified the isolate to have 99% similarity to Bacillus atrophaeus and it was deposited in the GenBank as Bacillus atrophaeus NR- 2 with accession number OP679007. The strain was characterized by ability to grow and synthesize the bioflocculant in alkaline conditions – pH 11. It was supposed that the strain can overcome adverse effects of environment – alkalinity and salinity by enhanced production of bioflocculant in stress. In the optimized medium (sucrose and tryptone used as C/N sources) the strain produced 4.76 mL bioflocculant.

Isolation, identification and optimization of exopolysaccharide-based bioflocculant synthesis by soil bacteria Bacillus atrophaeus NR-12

Bioflocculants are polysaccharide-based, biodegradable macromolecules synthesized by soil microorganisms. A bacterium prodicing an extracellular bioflocculant wasisolated from the salty and dry soil and identified as Bacillus atrophaeus. Effects of culture conditions including carbon sources, nitrogen sources, pH, shaker speed on bioflocculant production were studied. Isolate comparative analysis of 16S rRNA sequence identified the isolate to have 99% similarity to Bacillus atrophaeus and it was deposited in the GenBank as Bacillus atrophaeus NR- 2 with accession number OP679007. The strain was characterized by ability to grow and synthesize the bioflocculant in alkaline conditions – pH 11. It was supposed that the strain can overcome adverse effects of environment – alkalinity and salinity by enhanced production of bioflocculant in stress. In the optimized medium (sucrose and tryptone used as C/N sources) the strain produced 4.76 mL bioflocculant.

Adsorption of heavy metals from mine wastewater using amino-acid modified Montmorillonite

This study was conducted to identify the ability of a modern developed amino-acid modified montmorillonite clay (AA-Mont) to adsorb Cu2+, Pb2+ and Ni2+ cations from a multi-aqueous wastewater. This experimental was conducted to identify the potential of clay-based adsorbents to remediate pollutants from the PRA river basin. Experimental wastewater was prepared using a range of the lowest and highest recorded upstream and downstream heavy metal concentrations of u2+(10.84 mg/L-108.48 mg/g), Ni2+(7.99 mg/g–79.92 mg/g), and Pb2+(33.538 mg/L—335.38 mg/L). The variants of the designed clay-based adsorbents were L-Cysteine montmorillonites (Cys-Mont), Glycine montmorillonite (Gly-Mont), and L-lysine Montmorillonites (Lys-Mont) prepared at pH 4, 5, and 6 respectively. The experimental conditions were; Adsorbent dosages range = 25 mg–400 mg, pH = 6.0, Contact time = 24 hrs, Temperature = 25°C and Shaker speed = 180 rmp. After the adsorption experiments, it was identified that the maximum average removal efficiency obtained for Cu2+, Ni2+, and Pb2+ were all attained at adsorbent dosage 400 mg/L and in the order Lys-Mont (99.82%)>Cys-Mont (99.28%)>Gly-Mont (95.8%). Thus, the modified Lys-Mont clay exhibited the highest heavy metal adsorption capacity amongst the above three studied. The highest and lowest adsorbed metal pollutants amounts recorded for Lys-Mont were Cu2+ (86.49 and 8.65) mg/g, Ni2+ (44.51 and 5.99) mg/g, and Pb2+ (267.85 and 26.67) mg/g respectively. The number of metal ions adsorbed per unit mass for each metal cation tested decreased with increasing adsorbent dosage. The general order of selectivity documented for all the AA-Monts in this study was Pb>Cu>Ni which is similar to the levels in the prepared wastewater solution (Pb>Cu>Ni). The findings of this study have shown that heavy metal polluted river basins can remediated given the right conditions of temperature, adsorbent dosage, pH and agitation speed.