Kinetic Point Research Articles

Simple Parameters and Data Processing for Better Signal-to-Noise and Temporal Resolution in In Situ 1D NMR Reaction Monitoring.

In situ 1D NMR spectroscopic reaction monitoring allows detailed investigation of chemical kinetics and mechanism. Concentration versus time data are derived from a time series of NMR spectra. Each spectrum in the series is obtained by Fourier transform of the corresponding FID. When the spectrometer outputs FIDs recorded from multiple scans, the spectra benefit from an increase in signal-to-noise (S/N). However, this reduces the number of FIDs and, thus, kinetic data points. We report a simple alternative in which the same number of scans is acquired by the spectrometer, but each scan is saved independently. Signal averaging is then conducted by postacquisition processing. This leads to an increase in both the S/N and the number of kinetic data points and can avoid "overaveraging" effects. The entire series of single-scan FIDs spanning the reaction lifetime can be summed to yield a "total reaction spectrum" in which intermediates can be identified. The method can be applied in coherence with phase cycling to minimize spectral distortion during solvent signal suppression. Overall, the approach simplifies the preacquisition parameters to the estimation of the reaction duration and T1max and then the selection of the pulse angle, θ, and scan repetition time, τR, without the need to set the signal averaging before the experiment.

Kinetic insights into the relationships between anaerobic corrosion and decontamination of nanoscale zerovalent iron improved by sulfidation

There is a trade-off between corrosion and decontamination of nanoscale zero-valent iron (nZVI), which can be modulated by the sulfidation. Despite that, the insights into the relationship between anaerobic corrosion and decontamination of sulfidated nZVI (S-nZVI) remain unclear from a kinetic point of view. Herein, we used the variation of open-circuit potential to explore the anaerobic corrosion kinetic of S-nZVI. Taking Cr(VI) as the targeted contaminant, a negative correlation between decontamination and the corrosion of S-nZVI was identified during the first 10 min of reaction (R2 = 0.6919, slope = -0.7091) and after the 10 min of reaction (R2 = 0.7556, slope = -0.1307). Based on the results of TEM mapping, electrochemical impedance spectroscopy and XPS, this study further revealed that sulfidation not only enhanced the mass transfer of Cr(VI) toward nZVI in the initial stage of reaction, but also improved the electron transfer of nZVI toward Cr(VI) in the later stage of reaction. The ultimately enhanced removal and reduction of Cr(VI) by S-nZVI should be attributed to the introduction of iron sulfides (FeSx) that not only promoted the conductivity but also favored the affinity of nZVI toward Cr(VI). Overall, the kinetic insights presented in this study are valuable for understanding the process mechanisms of S-nZVI in anaerobic water and may extend to provide theoretical support for the development of enhanced methods for the remediation of contaminated groundwater using nZVI.

Phase Field Simulation Study of the β′ Precipitation Phase of Mg-Gd-Y Alloys

Abstract The key reinforcing precipitation phase in the aging precipitation sequence of Mg-Gd-Y alloys is the bamboo-leaf-like substable β′ phase, which can effectively inhibit the crystal base slip to enhance the age-hardening response of magnesium alloys. In this work, a phase field model of the aging precipitation process of Mg-Gd-Y ternary alloys was created by combining the phase field method and thermodynamic database. The microstructure evolution of the β′ precipitated phase in the isothermal aging process of Mg-Gd-Y alloys was simulated, and the impact of anisotropic parameters on the precipitated phase’s morphology was examined. Finally, the effect of Gd content on the β′ phase in the Mg-Gd-Y alloys was disclosed from the standpoint of the kinetics. β′ precipitation phase precipitation mechanism of Mg-Gd-Y alloys from the kinetic point of view. The results show that the anisotropic elastic energy and the interfacial energy work together to influence the shape of the β′ precipitation phase. Gd content increases lead to refined grains, an increase in the volume fraction of the Mg-Gd-Y alloy β′ precipitated phase, and a greater aspect ratio of the precipitated phase.

Predicting potential hard materials in Nb[sbnd]B ternary boride: First-principles calculations

To identify potential superhard materials, we conducted a comprehensive theoretical investigation of the thermodynamic and kinetic stability, mechanical properties, electronic structure, Debye temperatures and melting point of sixteen ternary transition metal borides NbTMBx (x = 1, 2, 4 and TM = Ti, V, Fe, Co, Ni, Zr, Ru, Hf, W, Os) using first-principles methods. Our findings indicate that, with the exception of NbFeB, NbRuB, and NbWB, all other borides exhibit both thermodynamic and kinetic stability. Notably, NbTiB4, NbVB4, NbZrB4 and NbHfB4 demonstrate superior hardness and enhanced resistance to deformation, with NbTiB4 showing an impressive hardness value of 40.84 GPa, positioning it as a promising candidate for superhard materials. Both NbVB4 and NbTiB4 have very high Debye temperatures and melting points and can be used in high temperature environments. We further explored the mechanical properties of NbTiB4 at elevated temperatures by employing a combination of first-principles and quasi-static methods. Our analysis reveals that the elastic constants and moduli of NbTiB4 decrease with increasing temperature. Additionally, bonding analysis indicates that all NbB ternary borides exhibit hybridization involving metallic, ionic, and covalent interactions, resulting in the formation of exceptionally strong covalent bonds between boron atoms.

Corrosion study of cola soft drink cans

The study of corrosion in aluminium packaging is fundamental to ensuring the quality and safety of the product. The varnish layer present on metal packaging aims to minimize any interaction between the food or drink and the metal, as well as minimizing the corrosion process. The acidic nature of soft drinks, as well as the ions present in solution, such as phosphates, benzoates or chlorides, play a strong role in the oxidative process of aluminum. This study evaluated the corrosion of the body of aluminum cola cans. The beverage was first characterized and the results obtained were: pH =2.5; 7.5 oBrix; chloride concentration of 0.17g/L, acidity 0.17 %m/m; density 1.04 g/mL and concentration of reducing sugars was 11.3 %m/m. The corrosion of aluminum in model solutions with different concentrations of citric acid and NaCl was studied via linear polarization for samples with and without varnish. The statistical analysis carried out, via factorial design 23 with a triplicate at the center point, showed that the corrosion rate (CR) of the sample with varnish was significantly influenced by temperatures above 45 oC in the range of chlorides studied. On the other hand, the CR of the sample without varnish was strongly influenced by the combination of high temperatures and high chloride concentrations. Removing the varnish resulted in a higher activation energy (AE = 67.48 kJ/mol) when removed with acetone and then polished with sandpaper compared to the sample with varnish (AE = 88.92 kJ/mol). From a kinetic point of view, this showed the protective effect of this layer and its effectiveness against corrosion. The ΔHo and ΔGo activation parameters of the process were positive, showing that corrosion is an endothermic process with increased disorder when the varnish is removed, respectively. It is therefore important to buy the product with the packaging in good condition to guarantee the integrity of the protective layer and its quality, since oxidation of the aluminum can lead to products that compromise the quality of the food or drink.

Predominant Binding Mode of Palmatine to DNA.

Palmatine is a protoberberine alkaloid, which may produce singlet oxygen under visible light irradiation and binds to DNA. The fact that singlet oxygen activation in palmatine may be triggered by environmental conditions, and in particular its interaction with nucleic acids, makes it a most suitable candidate for photodynamic therapy and DNA-targeted noninvasive anticancer strategies. Despite these remarkable properties, the actual binding mode between palmatine and DNA has not been resolved, yet. Its elucidation has indeed led to contrasting hypotheses. In this contribution, by using long-range molecular dynamic simulations and enhanced sampling approaches, we unequivocally identify that intercalation is the dominant binding mode of palmatine with DNA, from both a thermodynamic and kinetic point of view.

In Situ Raman Spectroscopy as a Valuable Tool for Monitoring Crystallization Kinetics in Molecular Glasses

The performance of in situ Raman microscopy (IRM) in monitoring the crystallization kinetics of amorphous drugs (griseofulvin and indomethacin) was evaluated using a comparison with the data obtained via differential scanning calorimetry (DSC). IRM was found to accurately and sensitively detect the initial stages of the crystal growth processes, including the rapid glass–crystal surface growth or recrystallization between polymorphic phases, with the reliable localized identification of the particular polymorphs being the main advantage of IRM over DSC. However, from the quantitative point of view, the reproducibility of the IRM measurements was found to be potentially significantly hindered due to inaccurate temperature recording and calibration, variability in the Raman spectra corresponding to the fully amorphous and crystalline phases, and an overly limited number of spectra possible to collect during acceptable experimental timescales because of the applied heating rates. Since theoretical simulations showed that, from the kinetics point of view, the constant density of collected data points per kinetic effect results in the smallest distortions, only the employment of the fast Raman mapping functions could advance the performance of IRM above that of calorimetric measurements.

Monitoring the Dynamics of the Galvanic Replacement Reaction to Develop Free-Standing Electrocatalysts

Hydrogen (H2) is well-known for its potential to become the future fuel and bring a more sustainable energy system [1]. The selective electrooxidation of organic compounds from biomass appears to be a possible substitute for the kinetically slow oxygen evolution reaction (OER) at the anode, which increases the electrical energy input for a conventional water electrolysis in alkaline media [2]. However, this approach is currently impeded by limited fundamental knowledge of the different active sites of electrocatalysts. The latter can be used to control selectivity at low potential and high current density to co-generate value-added products at the anode instead of CO2 by complete oxidation. Nanostructured gold-based multi-metal electrocatalysts can meet such objectives. Particularly in the electro-valorization of cellulosic biomass at electrode potentials unfavorable to C-C bond breaking and high overall cell voltage.To develop such electrocatalysts, we have initiated a multivariate methodology to study the dynamics of galvanic replacement between silver and gold. This procedure allows us to control nanoporosity and nanoalloying in the resulting gas diffusion electrode (GDE): GDE-Ag1-xAux. GDE-Ag represents the electrode upon which Ag particles were electrochemically grown prior to reaction with Au(III). Thermodynamically, silver with E°(Ag+/Ag) = 0.8 V vs SHE (standard hydrogen electrode) can be replaced by gold with E°(AuCl4 –/Au) = 1.0 V vs SHE according to: 3Ag + xKAuCl4(aq) → 3xAgCl + xKCl + Ag3-3xAux.[2,3] From a kinetic point of view, the challenge is to capture in real time the formation of metal cages of Ag-Au alloys after a '3by1' atomic exchange that introduces nanoporosity and electronic strain as silver and gold have a similar atomic radius. To interrogate the driving force behind this redox process, we have also established an electrochemical methodology to extract quantitative data, allowing detailed capture of the mixed electrochemical and mass transport (diffusion) kinetics. As the precipitation product AgCl leads to pore fouling, we have developed an efficient methodology to trigger its instant dissolution as soon as it is formed, thus promoting the production of a high-quality alloy. As shown in Figure 1, upon injection of a KAuCl4 solution into a degassed solution in contact with the GDE-Ag electrode, the open circuit potential (OCP) begins to change. This evolution is due to the modification of the electrochemical interface as silver atoms are progressively replaced by gold atoms. Thereby, leading to a regulated potential defined either by the Ag(I)/Ag redox couple, or by the Au(III)/Au pair. Interestingly, we found that the OCP variation logically depends on initial conditions such as Ag loading on the GDE, KAuCl4 concentration, Ag particle size, etc. This fundamental knowledge has led to the synthesis of efficient electrocatalysts for the oxidation of cellulose subunits in alkaline media with an onset electrode potential much lower than OER (E < 1 V vs RHE (reversible hydrogen electrode)). Indeed, the formation of an alloy phase, the creation of nanoporosity within it and the free-standing nature amplify, through synergistic and electronic effects, the electrocatalytic efficiency. Acknowledgments This work was funded by French National Research Agency (ANR-22-CE43-0004).

Constructing cascade electric fields and sulfur vacancies in Ni3S4/NiS2/v-Zn3In2S6 photocatalyst for efficient degradation of contaminants and H2 production

The increasing environmental pollution and looming energy crisis necessitate the development of advanced photocatalysts that demonstrate efficient separation and transfer of the photo-generated holes and electrons, as well as multiple functions to address the above issues. Herein, a bifunctional Ni3S4/NiS2/v-Zn3In2S6 photocatalyst has been constructed to degrade environmental hormones and antibiotics with simultaneous H2 production. Sulfur vacancies have been engineered in the Zn3In2S6 from a kinetic point of view to accelerate the separation of photogenerated charge carriers and act as active sites. Ni3S4 and NiS2 are introduced to construct cascade electric fields with Zn3In2S6 via ohmic junctions for spatially separated charge carriers and reduced hydrogen evolution potential. As a result, the composite exhibits enhanced photocatalytic H2 production and efficient degradation of bisphenol A, norfloxacin, and tetracycline, respectively. Specifically, the degradation pathways of BPA have been investigated based on Fukui calculations and liquid chromatography-mass spectrometry techniques. This work may shed new light on the design and construction of dual-function photocatalysts for wastewater treatment and H2 production.

Revealing the Kinetic Phase Behavior of Block Copolymer Complexes Using Solvent Vapor Absorption-Desorption Isotherms.

Controlling the self-assembled morphologies in block copolymers heavily depends on their molecular architecture and processing conditions. Solvent vapor annealing is a versatile processive pathway to obtain highly periodic self-assemblies from high chi (χ) block copolymers (BCPs) and supramolecular BCP complexes. Despite the importance of navigating the energy landscape, controlled solvent vapor annealing (SVA) has not been investigated in BCP complexes, partly due to its intricate multicomponent nature. We introduce characteristic absorption-desorption solvent vapor isotherms as an effective way to understand swelling behavior and follow the morphological evolution of the polystyrene-block-poly(4-vinylpyridine) block copolymer complexed with pentadecylphenol (PS-b-P4VP(PDP)). Using the sorption isotherms, we identify the glass transition points, polymer-solvent interaction parameters, and bulk modulus. These parameters indicate that complexation completely screens the polymer interchain interactions. Furthermore, we established that the sorption isotherm of the homopolymer blocks serves to deconvolute the intricacy of BCP complexes. We applied our findings by developing annealing pathways for grain coarsening while preventing macroscopic film dewetting under SVA. Here, grain coarsening obeyed a power law and the growth exponent revealed a kinetic transition point for rapid self-assembly. Overall, SVA-based sorption isotherms have emerged as a critical method for understanding and developing annealing pathways for BCP complexes.

Deciphering the irradiation induced fragmentation-rearrangement mechanisms in valence ionized CF3CH2F.

The increasing presence of 1,1,1,2-tetrafluoroethane (CF3CH2F) in the atmosphere has prompted detailed studies into its complex photodissociation behavior. Experiments focusing on CF3CH2F irradiation have unveiled an array of ions, with the persistent observation of the rearrangement product CHF2+ not yet fully understood. In this work, we combine density functional theory, coupled-cluster calculations with a complete basis set formalism, and atom-centered density matrix propagation molecular dynamics to investigate the energetics and dynamics of different potential pathways leading to CHF2+. We found that the two-body dissociation pathway involving an HF rearrangement, which was previously considered complex for CHF2+ formation, is actually straightforward but not likely due to the facile loss of HF. In contrast, our calculations reveal that the H elimination pathway, once thought of as a potential route to CHF2+, is not only comparably disadvantageous from both thermodynamic and kinetic points of view but also does not align with experimental data, particularly the lack of a rebound peak at m/z 101-102. We establish that the formation of CHF2+ is predominantly via the HF elimination channel, a conclusion experimentally corroborated by studies involving the trifluoroethylene cation CF2CHF+, a key intermediate in this process.

Removal of Aromatic Amino-derivatives from Aqueous Solutions Using Polymeric Supports Functionalized with Aminophosphonated/aminoacid-phosphonated Groups

Aromatic amines are the significant compounds used as intermediates in the organic synthesis, for obtaining such as azo dyes, antioxidants, fuel additives, corrosion inhibitors, pesticides, antiseptic agents, poultry medicine, and pharmaceutical synthesis. However, the presence of aromatic amines in water, even at very low concentrations, is extremely harmful to aquatic life and human health. Pollution of natural waters by aromatic amines is a serious environmental concern. The aim of this work was to obtain new adsorbents for use in the removal of aromatic amines from aqueous solutions. Styrene-15%divinylbenzene copolymers grafted with aminophosphonate groups (code: AP-S15%DVB) and amino acid-phosphonate groups (code: AM-S15%DVB) were used for the removal of pollutants such as: aniline, 2-methyl-aniline and 4-methyl-aniline. The adsorption capacity and the adsorption kinetic using the pseudo-first order and pseudo-second order equations were examined. From a kinetic point of view, it was established that the adsorption of the studied amino derivatives on the used adsorbents took place according to the pseudo-second order model. It was found that the adsorption rate constant increased with the increase of temperature, so the speed of the adsorption process increased. The obtained results confirm that the polymer adsorbents studied can be successfully used for the removal of aromatic amino derivatives from aqueous solutions for the purpose of wastewater treatment.

Adsorption of hexavalent chromium from aqueous solution onto corn cobs – activated carbon

This study evaluated the performance of a new activated carbon (CCs-AC) produced from corn cobs by boric acid activation for the effective removal of hexavalent chromium, a heavy metal with high potential to pollute the environment, from wastewater. For this purpose, with the help of parameters such as solution pH, contact time, initial Cr(VI) concentration, CCs-AC dose, desorption and temperature, the removal of Cr(VI) ions from aqueous solution by adsorption on CCs-AC was investigated from equilibrium, kinetic and thermodynamic point of view. As a result of the experiments, it was determined that the optimum solution pH was 2.0, the contact time was 4 hours, and the desorption solution was 3.0 M NaOH. From the kinetic data, it was determined that the adsorption was compatible with the pseudo-second order kinetic model and the maximum Cr(VI) adsorption capacity (123.7 mg/g) obtained from the Langmuir isotherm model showed that CCs-AC was of competitive quality with the literature. From the thermodynamic data, the positive ΔH value indicates that the adsorption is endothermic and the value of 12.00 kj/mol indicates that the adsorption is rather chemically driven. The negative ΔG value indicates that the process proceeds spontaneously with an increase in temperature, while the ΔS value indicates an increase in the amount of unused energy.

On‐column trace‐level formation of N‐nitrosamine in a liquid chromatography–mass spectrometry analytical system

A model reaction between di‐n‐butylamine and sodium nitrite was studied to investigate trace‐level N‐nitrosamine formation. Liquid chromatography–mass spectrometry (LC–MS) analysis of kinetic time points from an in‐progress reaction showed a systematic offset in nitrosamine concentration between quenched and unquenched samples. By combining samples of amine and nitrite in the needle of the autosampler it was demonstrated that N‐nitrosamine was formed in the LC–MS system. Further experimentation indicated that nitrosation was occurring on‐column.

Contrariety and Complementarity: Reading Spinoza’s Intersubjective Holism of Ideas with Aristotle’s Two Accounts of Motion

Do minds and ideas connect, interact, or even depend on each other, and if so, how exactly do they connect and interact? How to conceive of the mode and process of minds and ideas being in a network and connected in some way, that is, being intersubjective or social? Martin Lenz’s study Socializing Minds (2022) convincingly shows that, contrary to widespread opinion in philosophy of mind, at least some early modern philosophers, here Spinoza, Locke, and Hume, actually give a positive answer to the first question and present models that respond to the second question, thus, addressing what Lenz proposes to call ‘the contact problem’ and repudiating the idea that mentalism is necessarily bound to individualism. In this comment, I focus on a detail in Lenz’s reconstruction of Spinoza’s ‘metaphysical model’ of intersubjectivity of minds, namely the Aristotelian physical dynamism that would underlie Spinoza’s idea of the interaction of minds. While I agree that Spinoza’s model of the interaction of minds refers to the Aristotelian conception of motion, I argue that the guiding principle in natural motion is best understood not only in terms of contrariety but also in terms of complementarity. A closer reading of Aristotle’s theory of motion (kinēsis, metabolē) identifies two approaches to natural motion, one based on contrary principles, the other on complementary principles or powers (dynameis; potentiae). I suggest conceiving them as two sources for modelling natural motion and thus as two resources for a kinetic modelling of intersubjectivity and sociality. Admittedly, my proposal goes beyond Spinoza’s model of ideas in contact, and probably beyond Lenz's interpretation of that model, but it might enrich the imagination of the socialising of minds and ideas from a kinetic point of view, which, at least as I understand it, is precisely what Spinoza and Lenz thrive on.

Ionic transport kinetics of selective electrochemical lithium extraction from brines

Lithium extraction from brines by electrochemical De-intercalation/Intercalation method with LiFePO4 as host materials has attracted extensive attention, but the ionic transport properties and rate-determining step of this process are not fully understood. Therefore, to address this knowledge gap, we study the electrode process kinetics of LiFePO4/Li1-xFePO4 (0 <x < 1) in brines by electrochemical impedance spectroscopy. The results reveal that the diffusion of Li+ in electrode is the rate-determining step, the apparent diffusion coefficient DLi shows a trend of first increasing and then decreasing with the increase of electrode coating density, and the maximum value is obtained as 2.23 × 10−11 cm−2·s−1 at 55 mg·cm−2. The charge transfer resistance Rct and Warburg impedance Zω decrease with increasing temperature and do not change significantly with Li+ concentration, but Mg2+ has an inhibitory effect on Li+ charge exchange. Furthermore, the Li+ charge transfer at electrode/solution interface is differentiated for different de-lithiated Li1-xFePO4 electrodes, the Rct reaches a minimum around Li0.3FePO4. The diffusion of other competing cations is more difficult than Li+ in electrodes, which gives theoretical support for selective lithium extraction from brines from a kinetic point of view.

Microstructure and hydrogenation properties of RETMMg15 (RE= Nd, Gd; TM= Cu, Ni) alloys

In this study, five RETMMg15 (RE = Nd and/or Gd, TM = Ni and/or Cu) alloys have been successfully synthesized by induction melting of pure elements and characterized by XRD, BSE-SEM and EDXS. Their hydrogen storage properties have been studied from kinetic and thermodynamic points of view. The synthesized alloys NdNiMg15, NdCuMg15 and GdCuMg15 were composed of a RETMMg15 main phase with lesser proportions of α-Mg phase and other ternary phases. It has been found that substituting half of the RE (or TM) element by another RE (or TM) element leads to the formation of two solid solutions with composition: Nd0.5Gd0.5CuMg15 and NdCu0.5Ni0.5Mg15. Upon first hydrogenation, all alloys decomposed into binary or ternary hydrides. Next hydrogenation cycles allowed to store reversibly around 4.5 %wt. hydrogen. All alloys presented reduced MgH2 formation enthalpies as compared to pure Mg which is explained in term of “chemical milling”.

Role of kinetic chain in sports performance and injury risk: a narrative review.

The kinetic chain refers to the body's intricate coordination of various segments to perform a specific activity involving precise positioning, timing, and speed. This process is based on task-oriented and activity-specific pre-programmed muscle activation patterns enhanced by repeated practice. It demands muscular eccentric strength, joint flexibility, and musculotendinous elastic energy storage. The body core (lumbopelvic-hip complex) forms the kinetic chains' central point of activities in most sports because it facilitates load transfers to and from the limbs. The kinetic chain relationship with fascia, peripheral nerves, and tensegrity is fundamental to holistic human body movements. The kinetic chain function demands neuromuscular, sensorimotor, and neurocognitive control. Any blockage or defect in the kinetic chain can develop compensatory patterns, high demands on distal parts, and overuse and overload injuries. Taking a holistic approach and evaluating the integrity of the kinetic chain in athletes can significantly enhance efforts to improve sports performance and mitigate injury risk.

Cerium(IV) chitosan-based hydrogel composite for efficient adsorptive removal of phosphates(V) from aqueous solutions

The excess presence of phosphate(V) ions in the biosphere is one of the most serious problems that negatively affect aqueous biocenosis. Thus, phosphates(V) separation is considered to be important for sustainable development. In the presented study, an original cerium(IV)-modified chitosan-based hydrogel (Ce-CTS) was developed using the chemical co-precipitation method and then used as an adsorbent for efficient removal of phosphate(V) ions from their aqueous solutions. From the scientific point of view, it represents a completely new physicochemical system. It was found that the adsorptive removal of phosphate(V) anions by the Ce-CTS adsorbent exceeded 98% efficiency which is ca. 4-times higher compared with the chitosan-based hydrogel without any modification (non-cross-linked CTS). The best result of the adsorption capacity of phosphates(V) on the Ce-CTS adsorbent, equal to 71.6 mg/g, was a result of adsorption from a solution with an initial phosphate(V) concentration 9.76 mg/dm3 and pH 7, an adsorbent dose of 1 g/dm3, temperature 20 °C. The equilibrium interphase distribution data for the Ce-CTS adsorbent and aqueous solution of phosphates(V) agreed with the theoretical Redlich-Peterson and Hill adsorption isotherm models. From the kinetic point of view, the pseudo-second-order model explained the phosphates(V) adsorption rate for Ce-CTS adsorbent the best. The specific effect of porous structure of adsorbent influencing the diffusional mass transfer resistances was identified using Weber-Morris kinetic model. The thermodynamic study showed that the process was exothermic and the adsorption ran spontaneously. Modification of CTS with cerium(IV) resulted in the significant enhancement of the chitosan properties towards both physical adsorption (an increase of the point of zero charge of adsorbent), and chemical adsorption (through the presence of Ce(IV) that demonstrates a chemical affinity for phosphate(V) anions). The elaborated and experimentally verified highly effective adsorbent can be successfully applied to uptake phosphates(V) from aqueous systems. The Ce-CTS adsorbent is stable in the conditions of the adsorption process, no changes in the adsorbent structure or leaching of the inorganic filling were observed.

Single-Leg Hop Stabilization Throughout Concussion Recovery: A Preliminary Biomechanical Assessment.

Aberrant movement patterns among individuals with concussion history have been reported during sport-related movement. However, the acute postconcussion kinematic and kinetic biomechanical movement patterns during a rapid acceleration-deceleration task have not been profiled and leaves their progressive trajectory unknown. Our study aimed to examine single-leg hop stabilization kinematics and kinetics between concussed and healthy-matched controls acutely (≤7d) and when asymptomatic (≤72h of symptom resolution). Prospective, cohort laboratory study. Ten concussed (60% male; 19.2 [0.9]y; 178.7 [14.0]cm; 71.3 [18.0]kg) and 10 matched controls (60% male; 19.5 [1.2]y; 176.1 [12.6]cm; 71.0 [17.0]kg) completed the single-leg hop stabilization task under single and dual task (subtracting by 6's or 7's) at both time points. Participants stood on a 30-cm tall box set 50% of their height behind force plates while in an athletic stance. A synchronized light was illuminated randomly, queuing participants to initiate the movement as rapidly as possible. Participants then jumped forward, landed on their nondominant leg, and were instructed to reach and maintain stabilization as fast as possible upon ground contact. We used 2 (group) × 2 (time) mixed-model analyses of variance to compare single-leg hop stabilization outcomes separately during single and dual task. We observed a significant main group effect for single-task ankle plantarflexion moment, with greater normalized torque (mean difference = 0.03N·m/body weight; P = .048, g = 1.18) for concussed individuals across time points. A significant interaction effect for single-task reaction time indicated that concussed individuals had slower performance acutely relative to asymptomatic (mean difference = 0.09s; P = .015, g = 0.64), while control group performance was stable. No other main or interaction effects for single-leg hop stabilization task metrics were present during single and dual task (P ≥ .051). Greater ankle plantarflexion torque coupled with slower reaction time may indicate stiff, conservative single-leg hop stabilization performance acutely following concussion. Our findings shed preliminary light on the recovery trajectories of biomechanical alterations following concussion and provide specific kinematic and kinetic focal points for future research.