Values Of K1 Research Articles

Combined whole-body dynamic and static PET/CT with low-dose [18F]PSMA-1007 in prostate cancer patients

AimIn addition to significant improvements in sensitivity and image quality, the recent introduction of long axial field-of-view (LAFOV) PET/CT scanners has enabled dynamic whole-body imaging for the first time. We aim herein to determine an appropriate acquisition time range for static low-dose [18F]PSMA-1007 PET imaging and to investigate the whole-body pharmacokinetics of [18F]PSMA-1007 by dynamic PET with the LAFOV Biograph Vision Quadra PET/CT in a group of prostate cancer patients.MethodologyIn total, 38 prostate cancer patients were enrolled in the analysis for staging or re-staging purposes. Thirty-four patients underwent dynamic whole-body PET/CT (60 min) followed by static whole-body PET/CT and four patients underwent static whole-body PET/CT only. The activity applied was 2 MBq/kg [18F]PSMA-1007. The static PET images of 10-min duration (PET-10) were reconstructed and further split into 8-min (PET-8), 6-min (PET-6), 5-min (PET-5), 4-min (PET-4), and 2-min (PET-2) duration groups. Comparisons were made between the different reconstructed scan times in terms of lesion detection rate and image quality based on SUV calculations of tumor lesions and the spleen, which served as background. Analysis of the dynamic PET/CT data was based on a two-tissue compartment model using an image-derived input function obtained from the descending aorta.ResultsAnalysis of lesion detection rate showed no significant differences when reducing PET acquisitions from 10 up to 5 min. In particular, a total of 169 lesions were counted with PET-10, and the corresponding lesion detection rates (95% CI for the 90% quantile of the differences in tumor lesions) for shorter acquisitions were 100% (169/169) for PET-8 (95% CI: 0–0), 98.8% (167/169) for PET-6 (95% CI: 0–1), 95.9% (162/169) for PET-5 (95% CI: 0–3), 91.7% (155/169) for PET-4 (95% CI: 1–2), and 85.2% (144/169) for PET-2 (95% CI: 1–6). With the exception of PET-2, the differences observed between PET-10 and the other shorter acquisition protocols would have no impact on any patient in terms of clinical management. Objective evaluation of PET/CT image quality showed no significant decrease in tumor-to-background ratio (TBR) with shorter acquisition times, despite a gradual decrease in signal-to-noise ratio (SNR) in the spleen. Whole-body quantitative [18F]PSMA-1007 pharmacokinetic analysis acquired with full dynamic PET scanning was feasible in all patients. Two-tissue compartment modeling revealed significantly higher values for the parameter k3 in tumor lesions and parotid gland compared to liver and spleen, reflecting a higher specific tracer binding to the PSMA molecule and internalization rate in these tissues, a finding also supported by the respective time-activity curves. Furthermore, correlation analysis demonstrated a significantly strong positive correlation (r = 0.72) between SUV and k3 in tumor lesions.ConclusionsIn prostate cancer, low-dose (2 MBq/kg) [18F]PSMA-1007 LAFOV PET/CT can reduce static scan time by 50% without significantly compromising lesion detection rate and objective image quality. In addition, dynamic PET can elucidate molecular pathways related to the physiology of [18F]PSMA-1007 in both tumor lesions and normal organs at the whole-body level. These findings unfold many of the potentials of the new LAFOV PET/CT technology in the field of PSMA-based diagnosis and theranostics of prostate cancer.

Electrochemical analysis of gold nanoparticles multifunctionalised with Cytochrome c and a zinc Porphyrin

Cytochrome c (Cyt c), known for its functional redox capabilities, plays a pivotal role in biological processes such as the electron transport chain and apoptosis. However, understanding how different conjugation strategies impact its structural and redox characteristics is limited. To fill this gap, we investigated the effects of conjugating Cyt c and a zinc(II) porphyrin (Zn Porph) to gold nanoparticles (AuNPs). We used circular dichroism (CD) spectroscopy to detect structural conformational changes in Cyt c upon conjugation and time-of-flight secondary ion mass spectrometry (ToF-SIMS) to identify protein orientation. Cyt c was predicted to have different orientations depending on the size of AuNPs and methods used to conjugate the protein, it was hypothesised that the orientation of Cyt c may influence the redox properties of the protein. The electrochemical properties of Cyt c were assessed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). We used DPV-based to determine the heterogeneous rate constant (k0). The results show a lower k0for conjugated Cyt c than free Cyt c, likely due to structural changes in the protein. The spatial orientation of Cyt c had minimal influence on k0, while ligand density and AuNP size had an effect. The k0 value of Zn Porph did not decrease on conjugation. Despite these changes, Cyt c and Zn Porph maintained their electrochemical capabilities after conjugation.

Structural analysis of C8H6˙+ fragment ion from quinoline using ion-mobility spectrometry/mass spectrometry.

This study investigated the structures of fragment ions derived from the quinoline (C9H7N) radical cation using ion-mobility spectrometry and mass spectrometry. Ion mobility and mass analysis revealed that C8H6˙+ is the primary dissociation product resulting from the loss of HCN during collision-induced dissociation of the quinoline radical cation. The reduced mobility (K0) of the C8H6˙+ fragment product in helium gas was measured over a range of reduced electric fields (E/N = 20.8-27.4 Td) at room temperature. The experimental K0 values indicated that C8H6˙+ is a mixture of phenylacetylene and pentalene radical cations. Furthermore, quantum chemical calculations revealed two potential energy surfaces delineating the loss of HCN from the quinoline radical cation to form phenylacetylene radical cations.

Model Simulation and Rheological Research on Crosslinking Behavior of Polyethylene Resin.

The crosslinking behavior of polyethylene (PE) determines its exceptional performance and application. In this study, we investigated the crosslinking behaviors of different PE resins through model simulation and rheological methods. Specifically, the mathematical equation of "S" model was established for PE resin. According to this equation, the optimal maximum gel content for high-density polyethylene (HDPE) was found to be around 85%. Moreover, the maximum crosslinking degrees for different PE resins depended largely on their density and molecular weight. The melt viscosities before crosslinking in PE resins were highly influenced by their melt index. The higher melt indexes resulted in the lower storage moduli, improving melt processability during processing. In addition, the crosslinking rates of PE resins were strongly influenced by peroxide concentration, independent of PE resin structures. For high molecular weight and low-density PE resins, they exhibited decreased ti values, increased A0 values, and decreased k6 values. However, there were no noticeable variations in the values of k2 and phi among different PE resins. All simulated modeling outcomes showed remarkable consistency with the experimental rheological data. These findings are of strong significance in the industrial manufacture of PE resin.

Recognizing fake news based on natural language processing using the BM25 algorithm with fine-tuned parameters

The object of the research is the method of natural language processing (NLP) with balanced parameters of the BestMatch25 (ВМ25) algorithm to recognize and classify fake news based on natural language processing (NLP). The unsatisfactory accuracy and speed of existing methods for detecting fake news in unstructured input data demanded the development of a new approach for their effective detection. The study investigated the BM25 algorithm, methods for selecting parameters k1 and b, and their impact on the algorithm's effectiveness in detecting fake news. It was established that precise and detailed adjustment of these parameters is crucial in achieving optimal accuracy and data processing speed. The results showed that the successful selection of BM25 parameters improves the model's accuracy by up to 14 % compared to standard term frequency – inverse document frequency (TF-IDF) calculations. These results were made possible by experimentally tuning different combinations of k1 and b parameters, in which the algorithm shows the best speed indicator or the most accurate estimate of the importance of a term in a document. Balanced values of k1 and b parameters were identified, leading to the algorithm's optimal speed and accuracy in assessing word importance considering the input data's peculiarities. The balanced setting of the BM25 algorithm parameters explains the obtained results. They can be used for automated recognition and analysis of news and information on social media based on natural language processing. However, in practice, the effectiveness of the set of parameters depends on linguistic variations, content, and the theme within new input data sets

Fabrication and performance evaluation of rGO-PANI supported NiP/TMD based biosensors for electrochemical detection of dopamine

In this study, we present a novel approach for electrochemical sensing of DPA through the development of a unique electrode. It (WM-GP@NiMoP) composed of a mixed transition metal dichalcogenides (WS2-MoS2) supported by rGO and PANI, embedded via a facile electroless NiMoP plating technique. To evaluate the physico-chemical properties of the coatings, including phase analysis (X-Ray diffraction studies), morphology (Filed emission scanning electron microscopy), topology (Atomic force microscopy) and to assess the catalytic activity of the electrode for DPA sensing. The sensing behavior under various operating conditions, encompassing scan rate and pH of the analyte. The durability and performance evaluation were conducted to identify the consistent performance at an optimal pH value of 7 and it shown remarkable selective sensitivity and suppression of glucose and ascorbic acid interferences. The k0 values for the reversible electrode systems like dopamine was reasonable (5.3 ×10−10 cm/s) for the respective oxidation reactions. The CV analysis envisages the sensing potential of electrode towards DPA oxidation due to synergistic effect between PANI and rGO to MTMD on NiMoP coated electrodes. The work highlights the remarkable sensing capabilities of the WM-GP12 @NiMoP electrode in the field of electrochemical detection of DPA. Its exceptional sensitivity towards sensing of DPA establishes it as a significant advancement in electrochemical sensing technology.

Anisotropy of soil hydraulic properties induced by repeated machinery traffic in a Typic Argiudoll of the Argentinean Pampas Region

The increase in heavy machinery traffic due to crop sequence intensification under no-tillage (NT) management can lead to soil compaction, modifying the soil pore configuration, with negative effects on water dynamics. The objective of this work is to evaluate the residual effects of repeated machinery traffic under different soil water contents on the anisotropy of soil hydraulic properties. The residual effect of repeated machinery traffic under different soil moisture conditions (partially dry, PD, and wet, W) on soil compaction was evaluated and compared with the control treatment (no traffic, T0). Field infiltration using tension disc infiltrometer was carried out, and in laboratory, in order to analyse the anisotropy of soil hydraulic properties infiltration experiments were carried out on vertical and horizontal undisturbed soil samples. No significant differences in field soil hydraulic conductivity K(h) were observed between treatments. The W treatment showed a decrease on the transmission and storage pores in the vertical direction, as compared to T0. Anisotropic behavior of soil hydraulic properties was observed for the compacted treatments. The W treatment showed an increment in the transmission porosity in the horizontal direction. In addition, the W treatment presented higher values of transmission and storage pores in the horizontal direction as compared with the vertical direction. From laboratory infiltration experiments, it was observed a strong reduction on the hydraulic conductivity measured at 0, − 3 and − 6 cm water pressure heads (K0, K3 and K6) in the vertical direction under W treatment. An anisotropic behavior for both compacted treatments was observed, with higher values of K0 in the vertical direction under the PD treatment and higher values of K0 and K3 in the horizontal direction under the W treatment. These results show that machinery traffic under wet conditions causes a disruption in soil porosity, not only with a reduction of the pore space, but also with a change in its configuration.

Improvement of mechanical, biological, and electrochemical properties of Ti6Al4V alloy modified with Nb and Ag for biomedical applications

This study aims to evaluate the mechanical and biological properties of a spark plasma-sintered (SPS) Ti6Al4V alloy modified with 5 and 10 wt% niobium (Nb) together with 2 wt% Ag. Five batches of Ti6Al4V, Ti6Al4V-5 Nb, Ti6Al4V-10 Nb, Ti6Al4V-5 Nb-2Ag, and Ti6Al4V-10 Nb-2Ag were sintered using SPS at 1400 °C for 5 min. X-ray diffraction (XRD) analysis was used to identify the phases of the specimens. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray mapping analyses were also utilized to study the powder morphology, microstructure, and fractured surfaces of the samples. Three-point flexural strength and Vickers microhardness tests were performed and the fracture toughness (K1 C) was calculated subsequently. The bulk parts showed a very high building density, which means that the plasma sintering parameters were optimal. X-ray diffraction (XRD) analysis confirmed the existence of alpha and beta phases by adding niobium and silver. Potentiodynamic, electrochemical impedance spectroscopy, MTT assay, and antibacterial tests were also conducted to evaluate the biological properties of the sintered samples. The maximum values of flexural strength and K1 C were obtained for Ti6Al4V-5 Nb samples up to 1943 ± 12 MPa and 63 ± 1.1 MPa.m0.5, respectively. The hardness values of samples showed no significant difference by adding Nb and Ag. The samples containing Nb exhibit a lower passive current density compared to the pure Ti6Al4V alloy, suggesting that the addition of Nb positively influences corrosion resistance. According to the results of the antibacterial test, Nb slightly deteriorated the antibacterial properties, while after adding Ag, this property improved. The results of the MTT assay revealed that adding niobium and silver had no toxic effect on the samples.

Selective oxidation of histamine H2-Receptor antagonists by peracetic Acid: Kinetics and mechanism

Peracetic acid (PAA) is an emerging substitutive oxidant to chlorine disinfectants owing to the low generation of harmful by-products. Herein, we report PAA-induced oxidation of histamine H2-receptor antagonists (HRAs) via non-radical participation for the first time. Results showed that PAA can selectively oxidize HRAs with high reactivity to ranitidine (RNTD), nizatidine (NZTD), cimetidine (CMTD), and famotidine (FMTD), but low reactivity to roxatidine (RXTD). PAA-induced HRAs oxidation followed the second-order kinetic reaction, the apparent second-order reaction rate constants (k2, app) of RNTD, FMTD, CMTD and NZTD were 18.78 ± (2.4), 37.22 ± (6.1), 36.53 ± (7.8), 30.04 ± (2.4) M−1•s−1, respectively. The value of k2, app decreased as pH increased. Scavenging experiments indicated that PAA-induced HRAs oxidation proceeded via a non-radical process. The theoretical calculation and product analysis further reveal that the reaction involves the double-electron transfer from thioether sulfur in HRAs to peroxide bond. HRAs oxidation by PAA was not affected by water matrices (Cl-, HCO3–, HA), which has good applicability in surface water (SW) and wastewater (WW). Toxicity assessment indicated ecotoxicity of oxidation products was much lower than that of HRAs. This work provided a facile and emerging technology to eliminate the HRAs and their toxicity in the wastewater.

Studi Kinetika Ekstraksi Pektin dari Kulit Buah Pisang Kepok

Pectin is one of the polysaccharides that located in plant cell walls along with cellulose, lignin, and hemicellulose. The method for obtaining pectin is extraction. During the extraction process, there is reaction kinetic occur. This study aims to determine the extraction kinetics of kepok banana peel including reaction rate constants and activation energy with variations in extraction time. Secondary data that is processed are 1; 1,5; and 2 of pH extraction, 80oC and 90oC of temperature extraction, time extraction 70, 80, 90, and 100 minutes, and yield of pectin. The result showed that the value of the degradation constant (k2) is smaller than the value of the extraction constant (k1) on all variables. The highest Yemax is 41,88% that was found at pH 1,5; 90oC and 80 minutes of extraction times. The lowest value of activation energy for pectin formation (Ea1) is 17,812 kJ/mol and the highest value of activation energy for pectin degradation (Ea2) is 3,787 kJ/mol, both of which are found at pH 1,5. The optimum conditions for extracting pectin from kepok banana peel were at pH extraction 1,5 and 90oC of temperature extraction taking into account the values of k1, k2, Yemax, tmax, and activation energy.

Accuracy and Precision of New Optical Biometer Designed for Myopia Management in Measurement of Ocular Biometry.

This study provides information about the repeatability of Myopia Master and its agreement with Lenstar LS900, which might be useful for the practitioners involved in myopia management. Myopia Master is a new optical biometer that measures ocular biometry and refractive error. The purpose of this study is to assess its repeatability (intra-session and short-term inter-session) and its agreement with Lenstar LS900 for the measurement of axial length and corneal curvature. A total of 304 participants including 254 children (Mean age: 13.7 ± 1.6 years) and 50 adults (24 ± 2.9 years) underwent measurements on Myopia Master and Lenstar LS900 to obtain axial length (AL), flat K (K1), and steep K (K2). On a subset of 30 participants, measurements were obtained with Myopia Master in two sessions that were spread over 10 minutes to assess the short-term inter-session repeatability. The mean standard deviation of Myopia Master in the measurement of axial length in the total sample was 0.01 mm for intra-session, when the best three measurements were considered. The short-term inter-session mean standard deviation for AL, K1, and K2 was 0.06 mm, 0.15 D, and 0.21 D respectively. There were statistically significant differences in mean values of AL (-0.04 ± 0.06 mm), K1 (-0.07 ± 0.15 D), and K2 (-0.24 ± 0.29 D) between Lenstar LS900 and Myopia Master with the Lenstar providing slightly longer axial length and steeper K values. Adults showed better repeatability with Myopia Master and better agreement between the biometers for AL measurement than children. Neither axial length nor refractive error influenced the repeatability or agreement. Myopia Master is repeatable for the measurement of axial length and corneal curvature. Considering the differences in axial length between the Myopia Master and Lenstar LS900, caution must be applied when these biometers are used interchangeably.

Revisiting Néel 60 years on: The magnetic anisotropy of L10 FeNi (tetrataenite)

The magnetocrystalline anisotropy energy of atomically ordered L10 FeNi (the meteoritic mineral tetrataenite) is studied within a first-principles electronic structure framework. Two compositions are examined: equiatomic Fe0.5Ni0.5 and an Fe-rich composition, Fe0.56Ni0.44. It is confirmed that, for the single crystals modeled in this work, the leading-order anisotropy coefficient K1 dominates the higher-order coefficients K2 and K3. To enable comparison with experiment, the effects of both imperfect atomic long-range order and finite temperature are included. While our computational results initially appear to undershoot the measured experimental values for this system, careful scrutiny of the original analysis due to Néel et al. [J. Appl. Phys. 35, 873 (1964)] suggests that our computed value of K1 is, in fact, consistent with experimental values, and that the noted discrepancy has its origins in the nanoscale polycrystalline, multivariant nature of experimental samples, that yields much larger values of K2 and K3 than expected a priori. These results provide fresh insight into the existing discrepancies in the literature regarding the value of tetrataenite’s uniaxial magnetocrystalline anisotropy in both natural and synthetic samples.

Construction stability analysis of intersection tunnel in city under CRD method

The construction of city intersection tunnels cause multiple redistribution of surrounding rock stress, resulting in the engineering disasters such as instability in existing tunnels and collapses of ground buildings. To mitigate formation disturbances effectively, the Center Cross Diagram (CRD) method is employed in city tunnel construction. In this study, a numerical model for a city intersection tunnel is developed based on an underground circular roads project in Chongqing, China, to analyze the safety of the tunnel structure and the stability of ground buildings under the CRD method. The numerical simulation results obtain that the excavation of pilot-tunnel ➃ will reduce the surrounding rock stress and control the rock strata subsidence, and reveal that the excavation of pilot-tunnel ➃ is the key step of CRD method. The maximum compressive stress and tensile stress of surrounding rock first increase and then decrease during the excavation of pilot-tunnels ➀, ➁, ➂, and ➃. Simultaneously, the deformation of the ground building experiences a slow initial increase followed by a rapid rise before stabilizing. Furthermore, the excavation of the main tunnel leads to an increase of 0.73, 0.35, and 0.52 times in the vault subsidence value, left haunch convergence value, and right haunch convergence value of branch tunnel #1, respectively. Finally, the convergence process of branch tunnel #1 is discussed through the in-situ monitoring, which is divided into three stages: rapid deformation, deceleration deformation, and stable deformation. The final horizontal convergence value and subsidence value of cross-section K0+360 are respectively 84% and 78% of those at cross-section K0+395.

Klebsiella pneumoniae Infection in Alveolar Type II Epithelial Cells; Antibiotic-Vitamin Combination Therapeutic Effect

Aim: In this study, it was aimed to establish an infection model with Klebsiella pneumoniae on A549 Lung cancer cell line and to evaluate the effect of additional vitamins on the antibacterial effect of ampicillin sulbactam in the treatment. Cell culture and pathology results were determined in parallel with microbial analysis. Methods: Minimal inhibitory concentration (MIC), fractional inhibitory concentration (FIC), biofilm optical density of ampicillin sulbactam, vitamins E, K1 and P on Klebicella pneumoniae ATCC 700603 strain were determined. Cytotoxic activity on A549 cancer cell line in parallel with microbial analysis and pathology results were determined. Results: Ampicillin Sulbactam MIC dose range used in the treatment of Klebsiella pneumoniae infection is 16 mg/L. Looking at the FIC dose ranges, Vitamin K1+Ampicillin sulbactam, Vitamin P+Ampicillin sulbactam 2.5mg/ml+0.5µg/ml, Vitamin E+Ampicillin sulbactam 5mg/ml+0.5µg/ml, K1+P+E+Ampicillin sulbactam 2,5mg/ml+2.5mg/ml+5mg/ml+0.5µg/ml it was determined that it was. It was determined that it has a synergistic effect in combination with vitamins K1 and P antibiotics. In addition, in the presence of biofilm below 570 nm, the OD values of K1, P, E and K1+P+E+ antibiotic combinations were found to be 1.006, 0.969, 1.096 and 1.015, respectively. As a result of cell culture studies and evaluation of pathology results, it was determined that increasing the dose of Ampicillin sulbactam to 8 µg/ml increased the antibacterial effect and the vitamin combination was more effective. Conclusions: Antibiotic and vitamin combination was found to be more effective in Klebsiella pneumoniae infection in our study. This situation contributes to the search for alternative antimicrobials.

Determination of platinum valence state in alumina based catalysts by X-Ray fluorescence spectrometry

A novel method for the estimation of the platinum valence state in alumina-based catalysts using the intensities of L- and M-series lines of X-ray fluorescence spectrum is proposed. The measurements of metallic platinum (Pt0) and potassium tetrachloroplatinate K2[PtCl4] (PtII) were carried out using wavelength-dispersive spectrometer. We considered the ratios of the most intense groups of closely spaced platinum X-ray fluorescence spectrum L-series lines (Lα2/Lα1, Lβ2/Lβ1, Lβ4,6/Lβ1), as well as the broadening of PtMα1,2 line as parameters influenced by the chemical bond. After decomposition using a pseudo-Voigt function, the ratio of the Lα1 and Lα2 peaks amplitudes for K2[PtCl4] was 0.118, for Pt0–0.162; the difference in the ratio of peak amplitudes in the group of Lβ lines is much smaller. For the broadening of Mα1,2 line, the largest intensity difference (25 rel.%) between Pt0 and K2[PtCl4] was observed at 2.044 keV. Both studied analytical parameters for set of alumina-based catalysts were closer to values for Pt0 than to values of K2[PtCl4] that indicates that platinum in the studied catalysts is in a state close to metallic, probably with a slight shift towards the ionic state.

Internal Structure of Venus Based on the PREM Model

—Models of the internal structure of Venus have been constructed with a wide range of crustal thickness (30–70 km) and core radius (2800–3500 km). An analysis of the pressure values in the center of the planet allows us to conclude that the presence of a solid inner core is unlikely if the composition and temperature profile of Venus correspond to that of the Earth. Andrade’s rheology was used to take into account the inelasticity of the interior of Venus when calculating the tidal Love numbers and the angle of delay of the tidal hump. Comparison of experimental values of the Love number k2 with the model gives the radius of the core of Venus in the range of 3100–3500 km. It is shown that to determine the characteristic viscosity of the Venusian mantle, the key factor is the determination of the angle of retardation of the tidal bulge: values of 0.9° correspond to low viscosity and high temperature, and 0.4° to high viscosity and low temperature, so the planned measurements of tidal parameters and the moment of inertia of the planet in the VERITAS and EnVision missions will be able to impose restrictions on the distribution of viscosity and temperature in the interior of Venus.

CO2-plasma surface treatment of graphite sheet electrodes for detection of chloramphenicol, ciprofloxacin and sulphanilamide.

Graphite sheet (GS) electrodes are flexible and versatile substrates for sensing electrochemical; however, their use has been limited to incorporate (bio)chemical modifiers. Herein, we demonstrated that a cold (low temperature) CO2 plasma treatment of GS electrodes provides a substantial improvement of the electrochemical activity of these electrodes due to the increased structural defects on the GS surface as revealed by Raman spectroscopy (ID/IG ratio), and scanning electron microscopy images. XPS analyses confirmed the formation of oxygenated functional groups at the GS surface after the plasma treatment that are intrinsically related to the substantial increase in the electron transfer coefficient (K0 values increased from 1.46 × 10-6 to 2.09 × 10-3 cm s-1) and with reduction of the resistance to charge transfer (from 129.8 to 0.251 kΩ). The improved electrochemical activity of CO2-GS electrodes was checked for the detection of emerging contaminant species, such as chloramphenicol (CHL), ciprofloxacin (CIP) and sulphanilamide (SUL) antibiotics, at around + 0.15, + 1.10 and + 0.85 V (versus Ag/AgCl), respectively, by square wave voltammetry. Limit of detection values in the submicromolar range were achieved for CHL (0.08 μmol L-1), CIP (0.01 μmol L-1) and SFL (0.11 μmol L-1), which enabled the sensor to be successfully applied to natural waters and urine samples (recovery values from 85 to 119%). The CO2-GS electrode is highly stable and inexpensive ($0.09 each sensor) and can be easily inserted in portable 3D printed cells for environmental on-site analyses.

Internal Structure of Venus Based on the PREM Model

Models of the internal structure of Venus have been constructed with a wide range of crustal thickness (30–70 km) and core radius (2800–3500 km). An analysis of the pressure values in the center of the planet allows us to conclude that the presence of a solid inner core is unlikely if the composition and temperature profile of Venus correspond to that of the Earth. Andrade’s rheology was used to take into account the inelasticity of the interior of Venus when calculating the tidal Love numbers and the angle of delay of the tidal hump. Comparison of experimental values of the Love number k2 with the model gives the radius of the core of Venus in the range of 3100–3500 km. It is shown that to determine the characteristic viscosity of the Venusian mantle, the key factor is the determination of the angle of retardation of the tidal bulge: values of 0.9° correspond to low viscosity and high temperature, and 0.4° to high viscosity and low temperature, so the planned measurements of tidal parameters and the moment of inertia of the planet in the VERITAS and EnVision missions will be able to impose restrictions on the distribution of viscosity and temperature in the interior of Venus.

Nitrate Reduction through Al-Fe Alloy Catalyst: Effects of Activation Pre-Treatment Method and Alloy Type

This study explored the nitrate reduction by Al-Fe alloy. The nitrate conversions of fresh, 30-day and 90-day alloys were 78.1%, 42.8% and 9.5%, respectively. Water activation promoted the reducing ability of the alloy (98% nitrate removal), which was higher than that of copper deposited alloy (66%) and H2-reducing/acid/alkali/Cl− activated alloy (no enhancement). The effects of pre-treatments on the surface O fraction changes confirmed the activation results. With increased Fe:Al mass ratio in the alloy, nitrate conversion initially decreased and then increased again, verifying the proposed electron-donator activity of Al or Fe in alloys. Al-Fe30 had the highest NO3− conversion and Al13Fe4 content, so Al-Fe30 was selected. Significant differences in conversion were observed in alloy usages of 5–10 and 15–30 g/L. High reduction performance (nitrate below the detection limit and 19.1% N2 selectivity) was achieved under the optimal conditions: 15 g/L Al-Fe30, 150 min reaction and without pH adjustment. The rate constants of nitrate removal, nitrogen generation and ammonia generation were k1 = 1.43 × 10−2, k2 = 3.41 × 10−2 and k3 = 10.58 × 10−2 min−1, respectively. The value of (k2 + k3)/k1 was 10, indicating that the conversion of nitrate into nitrite was the rate-determining step. The repetition reaction was performed, and the rate constant decreased as the reaction step was repeated.

Numerical simulation of chemically reacting Darcy-Forchheimer flow of Buongiorno Maxwell fluid with Arrhenius energy in the appearance of nanoparticles

This investigation is designated for studying the inspiration of Darcy-Forchheimer flow of Maxwell nano fluid with nonlinear marvels of thermal radiation and bio convection of motile germs due to porous stretched sheet. Arrhenius energy, thermophoresis and convective Nield boundary conditions are novel aspects of this research. The exploration of heat and mass transfer in electrical conducting Maxwell fluid in the manifestation of nanoparticles is scrutinized. The misappropriate similarity functions are used to convert the couple of governing PDEs in to nonlinear set of ODEs. The resulting fasten of ODEs are numerically solved by applying the appropriate numerical tool shooting procedure with MATLAB solver code bvp4c. The encouragement of renowned parameters including Peclet number, Prandtl number, Bioconvective Lewis number, Rayleigh number, thermophoresis, Lewis number, Brownian motion and Hartmann number on momentum, energy, concentration and germ density profile has been deliberated in form of graphs and tables. We declared that the velocity curve declined for the developing value of inertia coefficient K1, magnetic number M and Deborah number Γ. The improvement in the values of the activation energy E growth in the temperature distribution.