Apparent Volume Research Articles

Comprehensive analysis of paddy seeds for designing of precision planters

Rice is a staple food for a major global population, and increasing rice production is crucial for addressing food security challenges. Precision planters have the potential to enhance rice productivity and input use efficiency. However, designing precision planters requires a comprehensive understanding of the physical and engineering properties of paddy seeds. This research paper aims to generate a database of these properties to aid in the design of precision planters. The study examined three popularly grown rice varieties (IR 64, JR 206, and Kranti) in terms of their physical and engineering properties. The seeds were analyzed at different stages, including the dry stage, 24 hours soaking and 48 hours of soaking. The results shows design values of metering unit with maximum grain dimensions (10.20 mm length, 3.39 mm breadth, 2.68 mm thickness), equivalent diameter 4.336 mm, sphericity 0.456, average friction coefficient 0.48, and maximum apparent volume 9.7 cm3. Based on the results design values for metering mechanism is calculated which is very much essential for designing of precision seeder for rice.

Volumetric and viscometric study on the interaction of amino acid (valine) with an aqueous solution of cationic surfactant, Cetyltrimethylammonium Bromide (CTAB), at 298.15, 303.15, 308.15, and 313.15 K

Interactions between the surfactant (CTAB) and amino acid (valine) were investigated using density and viscosity data. These data were utilized to calculate apparent molar volume, fv, and partial molar volume also known as limiting molar volume f0v and these parameters were further used to find out solute-solvent interactions between amino acid and surfactant at 298.15, 303.15, 308.15 and 313.15 K temperatures.

Thermal activation and dislocation dynamics in Ti–6Al–4V alloy

The tensile stress relaxation behaviour is experimentally investigated for Ti–6Al–4V alloy across a temperature range of −60, −30, 20, 120, and 230 °C. Interestingly, the results revealed that the alloy exhibited the lowest resistance to stress relaxation at 20 °C, i.e., room temperature. This resistance was found to increase with both increasing and decreasing test temperatures. The apparent activation volume values, which indicate the dislocation mean free path, increase with strain due to a decrease in activable dislocation segments. Furthermore, these values were found to be proportional to the test temperature, resulting from higher dislocation mobility at moderate temperatures (230 °C and 120 °C) than at lower temperatures. Our experimental and analysis results indicate that dislocation-mediated plastic deformation predominates in all tested temperature conditions. However, the transition from planar to wavy dislocation configuration, observed through Transmission Electron Microscopy (TEM) between temperatures of −30 and 20 °C, along with the change in activation volume, suggests a critical temperature at which dislocation mechanism changes in the Ti–6Al–4V alloy. A rapid exhaustion of a substantial amount of mobile dislocation density, which significantly contributes to time-dependent deformation was observed at 230 °C. These findings provide valuable insights into the mechanisms underlying the stress relaxation behaviour of Ti–6Al–4V alloy at different operational temperatures, offering practical implications for improved alloy design and manufacturing processes.

Can initial apparent diffusion coefficient and tumour volume predict future metastases in treatment-naive patients with laryngeal squamous cell carcinoma

Can initial apparent diffusion coefficient and tumour volume predict future metastases in treatment-naive patients with laryngeal squamous cell carcinoma

Effect of Tween and CTAB surfactants on aqueous solubility of the silibinin anticancer drug studied by using physicochemical properties at 310.15 K

The silibinin (SB) is an anticancer drug exhibits partial solubility in aqueous medium due to its slightly hydrophobic nature. In this context, the aqueous solubility of SB with Tween 40 (Tw 40), Tween 60 (Tw 60), Tween 80 (Tw 80) and Cetyltrimethylammonium bromide (CTAB) surfactants at 310.15 K are reported. The physicochemical properties (PCPs) such as density (ρ, g cm−3), Apparent Molar Volume (Vϕ, cm3·mol−1), viscosity (η, mPa.s), surface tension (γ, mNm−1), friccohesity (σ, s.m−1), activation energy (Δµ2*, kJ/mol), and molecular radii (r, nm) of SB with aqueous solution of Tw 40, Tw 60, Tw 80 and CTAB surfactants separately. The PCPs reflects the state of intermolecular forces (IMF) developed between SB and aqueous solutions of Tween (40, 60, 80) and CTAB surfactants with concentration varied from 25 to 150 µM (µM). This study focused on intermolecular interacting mechanism determined by using PCPs to evaluate self-aggregation potential of SB in aqueous surfactants solution. The PCPs data furnished interaction and structure breaking behavior of SB with surfactant molecules. The development of hydrogen bond (HB), hydrophilic, hydrophobic and electrostatic interactions of SB with surfactants which revealed that the structure dependent interacting activities enhances with increasing concentration of SB in aqueous surfactants.

Process intensification of the electrodialysis metathesis for calcium bromide preparation: Effects of key influencing factors and phenomena of water migration

Calcium bromide, a high-value bromine resource, is widely used in the industrial synthesis processes and mercury removal from flue gas. However, there are some problems in traditional preparation methods for calcium bromide, such as long processing time, environmentally unfriendly and so on. To address these challenges, an electrodialysis metathesis (EDM) process was developed in this study to prepare high value-added calcium bromide using sodium bromide and calcium chloride as the raw materials. In order to obtain calcium bromide with high purity and improve the economic efficiency of the EDM process, the key influencing factors were investigated. Furthermore, the water migration during EDM was analyzed, and potential prospects of reducing apparent water flux volume by lowering temperature, current density, and the concentration difference between the dilute chamber and the concentrated chamber within an appropriate range. As a result, a calcium bromide product with a purity higher than 99 % was obtained with no Cl− detected. Mass fraction of Na+ was found to be 0.016 %, meeting the standards required by the industry. This method provides a new perspective and a good guide for the efficient preparation of highly valued bromine resources.

A study of enhancing the solubility of streptomycin sulphate in sorbitol using volumetric, acoustic and viscometric properties

The various molecular interactions present between streptomycin sulphate and sorbitol were evaluated using density (ρ), speed of sound (u) and viscosity (η) studies. All these studies have been obtained at different temperatures (300.15, 305.15, 310.15 ad 315.15) K and at 0.1 MPa pressure. The values obtained from these studies have been utilized to calculate the various thermodynamic parameters such as apparent molar volume (ΦV), apparent molar isentropic compression (ΦK), partial molar volume (ΦVo), partial molar isentropic compression (ΦKo), partial molar expansibility (ΦEo) of solute for SMS in various solutions of sorbitol. The data obtained from viscosity studies have been utilized to determine Falkenhagen coefficient (A), Jones- Dole coefficient (B), dB/dT and viscosity B-coefficient of transfer (Btr). A complete discernment into the physicochemical interactions present in the studied system have been redeemed through the scrutiny of above calculated parameters.

Pharmacokinetics of tildipirosin in estuarine (Crocodylus porosus) and freshwater (Crocodylus siamensis) crocodiles

Tildipirosin is a macrolide antimicrobial. It is authorised for the treatment and prevention of respiratory disease in cattle and pigs. There are no data on its administration in crocodiles. Therefore, this study evaluated the disposition kinetics of tildipirosin after intravenous (dose: 2 mg/kg) and intramuscular (doses: 2 and 4 mg/kg) administration in two crocodilian species (estuarine and freshwater; n = 5). Tildipirosin plasma concentrations were quantified by a validated HPLC method. Plasma concentrations obtained at each extraction time were analysed by non-compartmental methods. In the estuarine and freshwater crocodiles, the apparent volumes of distribution of tildipirosin after intravenous administration were 0.36 ± 0.10 and 1.48 ± 0.26 L/kg, respectively. These values, suggesting poorer tissue distribution, were much lower than those obtained in mammals. There was complete bioavailability of tildipirosin after intramuscular route at a dose of 2 mg/kg; however, at a dose of 4 mg/kg the bioavailability decreased by about 20–25 %. Furthermore, the pharmacokinetics of tildipirosin were markedly different in the two crocodilian species. Considering a MIC of 0.5 µg/mL, the surrogate marker AUC0–24/MIC indicates that tildipirosin would greatly exceed the value of 65 h for both crocodile species and dose levels tested. This suggests that both doses (2 and 4 mg/kg) may provide a bactericidal effect. Therefore, based on the absence of adverse reactions following the administration of tildipirosin in both crocodilian species, and considering its favourable pharmacokinetic properties, tildipirosin may be useful in treating infections in these reptiles.

Guiding Dyslipidemia Treatment: A Population Pharmacokinetic-Pharmacodynamic Framework for Obicetrapib.

Obicetrapib is a selective inhibitor of cholesteryl ester transfer protein that is currently in phase 3 of development for the treatment of dyslipidemia as adjunct therapy. The purpose of this study was to comprehensively characterize the pharmacokinetic (PK) and pharmacodynamic (PD) disposition of obicetrapib. Data from 7 clinical trials conducted in healthy adults and those with varying degrees of dyslipidemia were included for model development. The structural model that best described obicetrapib PK was a 3-compartment model with 4-compartment transit absorption and first-order elimination. Body weight was the only covariate found to significantly explain observed variability and was therefore included using allometric scaling on all disposition parameters. For a typical patient weighing 75 kg, the estimated apparent total body clearance and apparent volume of distribution of the central compartment was 0.81 L/h and 36.1 L, respectively. The final PK model parameters were estimated with good precision and were ultimately leveraged to sequentially inform 2 turnover models that describe obicetrapib's effect on low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) concentrations. The maximum stimulatory effect of obicetrapib on LDL-C loss was estimated to be 1.046, while the maximum inhibitory effect of obicetrapib on HDL-C loss was 0.691. This corresponds to a predicted typical maximum percent change from baseline LDL-C and HDL-C of 51.1% and 224%, respectively. The final sequential model described obicetrapib PKPD well and was ultimately able to both demonstrate evidence of internal consistency and support decision-making throughout the development lifecycle.

Pharmacokinetics of famotidine in goats after intravenous administration.

There is currently limited pharmacokinetic data for the use of famotidine in goats for treatment and prevention of abomasal ulceration. The objective of this study was to determine the pharmacokinetic parameters after a single intravenous administration of famotidine (0.6 mg/kg). Famotidine was administered to six healthy goats and plasma samples were collected over a 24-h period. The famotidine concentration was measured using reverse phase high-performance liquid chromatography (HPLC). Non-compartmental analysis was then used to determine the pharmacokinetic parameters. The maximum plasma concentration was estimated at 5476.68 ± 1530.51 ng/mL and elimination half-life was estimated at 18.455 ± 13.26 min. The mean residence time was determined to be 19.85 ± 12.14 min with the apparent volume of distribution being estimated at 321.924 ± 221.667. The area under the curve was determined to be 54230.08 ± 24947.6 min*ng/mL. Total exposure and elimination half-life were less than what has been reported in cattle and horses. Future research evaluating the pharmacokinetics of subcutaneous administration and looking at the pharmacodynamics of famotidine in goats is needed to determine the effectiveness of famotidine on raising pH levels of the abomasum.

Pharmacokinetics of oral clonazepam in growing commercial pigs (Sus scrofa domestica).

Clonazepam causes sedation and psychomotor impairment in people. Due to similarities between people and swine in response to benzodiazepines, clonazepam may represent a viable option to produce mild-to-moderate tranquillization in pigs. The objective of this study was to determine the pharmacokinetic profile of a single oral dose (0.5 mg/kg) of clonazepam in eight healthy, growing commercial cross pigs. Serial plasma samples were collected at baseline and up to 96 h after administration. Plasma concentrations were quantified using reverse-phase high-performance liquid chromatography, and compartment models were fit to time-concentration data. A one-compartment first-order model best fits the data. Maximum plasma concentration was 99.5 ng/mL, and time to maximum concentration was 3.4 h. Elimination half-life was 7.3 h, mean residence time 7.4 h, and apparent volume of distribution 5.7 L/kg. Achieved plasma concentrations exceeded those associated with psychomotor impairment in people although pharmacodynamic effects have not been investigated in pigs. A simulated oral regimen consisting of 0.35 mg/kg administered every 8 h to pigs would achieve plasma concentrations above 32 ng/mL which are shown to produce psychomotor impairment in people. Further studies to test the clinical efficacy of these dosages in commercial and miniature pigs are warranted.

Thermodynamic and spectroscopic investigation of the molecular interactions among vitamin B5, calcium salt, and cyclodextrins in aqueous media

The pharmaceutical industry aims to enhance drug development processes by gaining a deeper understanding of the physiochemical properties of drug molecules. This study provides a comprehensive analysis of the volumetric and compressibility properties of the drug, calcium-D-pantothenate (CDP) in aqueous solutions of cyclodextrins (β-CD/HP-β-CD). By measuring the density and speed of sound, we have evaluated various parameters, including apparent molar volume, compressibility, and their corresponding infinite dilution parameters. In addition to this, positive transfer parameters such as ΔtrVs,φo and ΔtrKs,φo of solute provide insights into solute-co-solute and solute–solvent interactions. Also, Hepler’s constant offers valuable information on the structure-breaking characteristics of the studied drug in cyclodextrin medium. The decrease in molar conductance of the binary system after adding cyclodextrin supports our theoretical observation from volumetric and compressibility studies. Positive values of activation energy favor spontaneity and the solubilization process. Furthermore, the 1H NMR study demonstrates that the β-CD molecule interacts more strongly with CDP molecules as compared to HP-β-CD.

Changes of PK/PD of Meropenem in patients with abdominal septic shock and exploration of clinical rational administration plan: a prospective exploratory study

This study aimed to explore the changes of pharmacokinetic parameters after meropenem in patients with abdominal septic shock after gastrointestinal perforation, and to simulate the probability of different dosing regimens achieving different pharmacodynamic goals. The study included 12 patients, and utilized high performance liquid chromatography-tandem mass spectrometry to monitor the plasma concentration of meropenem. The probability of target attainment (PTA) for different minimum inhibitory concentration (MIC) values and %fT > 4MIC was compared among simulated dosing regimens. The results showed that in 96 blood samples from 12 patients, the clearance (CL) of meropenem in the normal and abnormal creatinine clearance subgroups were 7.7 ± 1.8 and 4.4 ± 1.1 L/h, respectively, and the apparent volume of distribution (Vd) was 22.6 ± 5.1 and 17.2 ± 5.8 L, respectively. 2. Regardless of the subgroup, 0.5 g/q6h infusion over 6 h regimen achieved a PTA > 90% when MIC ≤ 0.5 mg/L. 1.0 g/q6h infusion regimen compared with other regimen, in most cases, the probability of making PTA > 90% is higher. For patients at low MIC, 0.5 g/q6h infusion over 6 h may be preferable. For patients at high MIC, a dose regimen of 1.0 g/q6 h infusion over 6 h may be preferable. Further research is needed to confirm this exploratory result.

Population pharmacokinetics of nirmatrelvir in Chinese patients with COVID-19: Therapeutic drug monitoring and dosing regimen selection in clinical practice

ObjectivesTo establish a population pharmacokinetics (PopPK) model of nirmatrelvir in Chinese COVID-19 patients and provide reference for refining the dosing strategy of nirmatrelvir in patients confirmed to be infected with SARS-CoV-2. MethodsA total of 80 blood samples were obtained from 35 mild to moderate COVID-19 patients who were orally administered nirmatrelvir/ritonavir tablets. The PopPK model of nirmatrelvir was developed using a nonlinear mixed effects modelling approach. The stability and prediction of the final model were assessed through a combination of goodness-of-fit and bootstrap method. The exposure of nirmatrelvir across various clinical scenarios was simulated using Monte Carlo simulations. ResultsThe pharmacokinetics of nirmatrelvir was well characterised by a one-compartment model with first-order absorption, and with creatinine clearance (Ccr) as the significant covariate. Typical population parameter estimates of apparent clearance and distribution volume for a patient with a Ccr of 95.5 mL·min−1were 3.45 L·h−1 and 48.71 L, respectively. The bootstrap and visual predictive check procedures demonstrated satisfactory predictive performance and robustness of the final model. ConclusionThe final model was capable of offering an early prediction of drug concentration ranges for different nirmatrelvir dosing regimens and optimise the dose regimen of nirmatrelvir in individuals with confirmed SARS-CoV-2 infection.

Structural elucidation of ternary mixtures of L‐valine/glycyl‐L‐valine and water + 1‐decyl‐3‐methylimidazolium bromide: Apparent molar properties at infinite dilution and expansivities

AbstractThis work comprises ternary systems of water + SAIL,1‐decyl‐3‐methylimidazolium bromide, and (S)‐2‐Amino‐3‐methylbutanoic acid generally identified as L‐valine/ (S)‐2‐(2‐Aminoacetamido)‐3‐methylbutanoic acid usually described as glycyl‐L‐valine, densities, and sound speed data have been computed at four operating temperatures, i.e., 288.15 to 318.15 K. Calculated density data have utilized for calculation of various thermodynamic parameters like Vϕ (apparent molar volume), (apparent molar volumes at infinite dilution), and calculated speed of sound statistics used to determine Kϕ,s (apparent molar isentropic compression), Ks (partial molar isentropic compression at infinite dilution). In our systems, the hydrophilic‐ionic interactions that are produced by co‐sphere overlap models are predominant. The Hepler's constant is used to analyze the solute's capacity to create or destroy solvent structures. The interaction parameter is computed using the McMillan‐Mayer theory. Understanding structure‐making, solvation characteristics, and numerous modifications in the ternary system of L‐valine/Glycyl‐L‐valine, water, and [C10MIm] [Br] is aided by a variety of thermodynamic factors.

Physiochemical study of 1-methyl imidazole trifluoro methane sulfonate ionic liquid in aqueous and aqueous amino acid solutions at different temperatures

The experimental density and speed of sound of 1-methyl imidazole trifluoro methane sulfonate ionic liquid in aqueous binary ([MIm][OTf]+H2O) solution and aqueous ternary ([MIm][OTf] + 0.05 mol.kg−1 aqueous glycine) solution are reported in the dilute concentration range (0.06 to 0.16 mol.kg−1) at the temperature between 288.15 and 318.15 K with 5K interval and at atmospheric pressure. These density (ρ) and speed of sound (u) data are utilized to derive various significant thermophysical parameters namely apparent molar volume of solute (Vϕ), isentropic compressibility of solution (κs) and apparent molar isentropic compressibility of solute (KS,ϕ). The limiting apparent molar volume (Vϕ0) and limiting apparent molar isentropic compressibility (KS,ϕ0) of [MIm][OTf] are estimated by extrapolation methods. By using Vϕ0and KS,ϕ0data of the studied binary and ternary systems, the values of transfer volumes i.e. volume changes due to transfer (ΔtrVϕ0)and transfer compressibility i.e. compressibility changes due to transfer(ΔtrKsϕ0) from aqueous to aqueous amino acid solution are estimated. The observed ΔtrVϕ0and ΔtrKsϕ0values are temperature dependent. The outcomes of this investigation are framed within the context of solute-solute and solute-solvent interactions.

Excess properties and intermolecular interactions of 2-methoxyethanol + ethylenediamine binary system: Density, viscosity, spectral analyses, computational chemistry, and CO2 absorption property

To examine the fundamental physicochemical properties as well as intermolecular interactions for the 2-methoxyethanol (EGME) (1) + ethylenediamine (EDA) (2) binary system, this work systemically measured the density (ρ) and viscosity (η) values of the binary system with various mole ratios at P = 100.5 kPa and T = (298.15–318.15) K with the growth gap of 5 K. The as-measured values of the pure substances were compared with literature data. Multiple semi-empirical formulas were used to fit ρ and η values, and the absolute average deviations (AAD%) were calculated. After that, the excess molar volume (VmE), partial molar volume (V¯), apparent molar volume (Vφ), viscosity deviation (Δη), excess activation of Gibbs free energy (ΔG∗E), and several thermodynamic properties of the binary system were systemically analyzed. According to analysis results, it has been proven that the interaction exists between EGME and EDA molecules. And then, excess properties were fitted to the Redlich-Kister equation using multi-parametric nonlinear regression analyses, and standard deviations (σ) were calculated. In addition, based on various characterization methods including Raman, ultraviolet (UV), and nuclear magnetic resonance hydrogen (1H NMR) spectral analyses and density functional theory (DFT) calculation results, it is demonstrated that there is intermolecular hydrogen bonds in EGME (1) + EDA (2) binary system as the form of –OH⋯NH2–, which was consistent with the existence forms of intermolecular hydrogen bonds in different alcohol-amine systems from references. Finally, CO2 absorption capacity by pure EDA, pure EGME, and the EGME (1) + EDA (2) binary system were severally determined.

Physicochemical studies of adenosine in the presence of aqueous caffeine and theophylline solutions, & sodium valproate with γ‐amino butyric acid in aqueous medium at T = (288.15–318.15) K and at p = 1 × 105 Pa

AbstractIn human body, drug‐neurotransmitter interactions have been the most significant process. Whereas, adverse reactions may be accompanied by unexpected interaction, which puts an individual in danger of life. Thus, the interactions between adenosine (ADN) and sodium valproate (SV) with caffeine (CAF), theophylline (TPY) and γ‐amino butyric acid (GABA) have been studied. Various properties like densities, ρ and speed of sound, u, have been used to calculate apparent molar volumes (V2,ϕ) and apparent molar isentropic compression (Ks,2,ϕ) for ADN and SV in aqueous (5, 10, 15 and 20 mmol kg−1) CAF, TPY and GABA solutions at T = (288.15–318.15) K and at pressure p = 1 × 105 Pa. The results of various interactions that occurred by mixing the solutions have been interpreted. Exothermicity is indicated by the negative values of standard molar enthalpy of transfer, ΔtrΔdilH0, obtained from the calorimetry. UV‐absorption and 1H NMR studies suggest that there is a dominance of solute‐cosolute interactions due to hyperchromic shift and shielding effect.

Rockburst early warning based on microseism and critical point theory

During the tunnel construction, rockbursts occurred, posing a risk to safety. To mitigate this risk, a microseismic monitoring system was installed in the tunnel to provide early warning of rockbursts. After conducting research on the evolution of microseismic events in terms of number, moment magnitude, and energy within a specific time frame, an approach for rockbursts risk assessment based on microseismic moment magnitude was proposed. The critical point theory was utilized to quantitatively analyze the energy release process of the surrounding rock before intense rockbursts. This analysis revealed that the energy release of the surrounding rock before rockbursts can be divided into three stages: stable energy release stage, transitional energy release stage and accelerated energy release stage. The obtained process, derived from the critical point theory, was compared and analyzed alongside the evolution process of value of b, cumulative apparent volume, and energy index.

Population pharmacokinetics and dosing optimization of perampanel in children with epilepsy: A real-world study.

The purposes of this study were to explore the pharmacokinetics of perampanel (PER) in children with epilepsy, identify factors that contribute to pharmacokinetic variations among subjects, evaluate the connection between PER exposure and clinical outcome, and establish an evidence-based approach for tailoring individualized antiepileptic treatment in this specific population. In this prospective study, PER plasma concentrations and genetic information on metabolic enzymes were obtained from 194 patients younger than 18 years. The disposition kinetics of PER in pediatric patients following oral dosing were characterized using nonlinear mixed effect models. The effective range for the plasma concentration of PER was determined by assessing the efficacy and safety of PER treatment and analyzing the relationship between drug exposure and clinical response. Monte Carlo simulations were then performed to evaluate and optimize the current dosing regimens. The pharmacokinetic profile of PER was adequately described by a one-compartment model with first-order absorption and elimination. Body weight, total bilirubin level, and concomitant oxcarbazepine were found to have significant influences on PER pharmacokinetics. Model estimates of apparent clearance and volume of distribution were .016 ± .009 L/h/kg and 1.47 ± .78 L/kg, respectively. The effective range predicted from plasma concentration data in responders was 215-862 μg/L. Dosing scenarios stratified according to essential covariates were proposed through simulation analysis. In this study, we captured the pharmacokinetic/pharmacodynamic characteristics of PER in pediatric epilepsy patients through analysis of real-world data and adopted a pharmacometric approach to support an individualized dosing strategy for PER in this specific population.