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1.
Laryngoscope ; 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-39016182

ABSTRACT

INTRODUCTION: Osteotomies are routinely incorporated in rhinoplasty, however, the influence of mass, velocity, kinetic energy (KE), and momentum (p) of the mallet on fracture patterns has not been studied. METHODS: An experimental sledge guillotine setup was designed simulating a mallet strike with adjustable height and mass and 2 mm-thick Sawbone blocks. KE and p were calculated using KE = ½ mass × velocity2 and p = mass × velocity formulas. Fracture lengths and angles were measured. RESULTS: Ten groups with varying mallet masses and drop heights were tested with 10 bones per group. Fracture length positively correlated with KE (R = 0.542, p < 0.001) and p (R = 0.508, p < 0.001). Fracture angle also positively correlated with KE (R = 0.367, p < 0.001) and p (R = 0.329, p < 0.001). In groups with similar KE, osteotomies with higher p (heavier mallet with slower velocity) had greater fracture lengths (29.31 ± 0.68 vs. 27.68 ± 2.12 mm, p = 0.013) but similar fracture angles (p = 0.189). In groups with similar p, osteotomies with higher KE (lighter hammer with faster velocity) had significantly greater fracture lengths (28.28 ± 1.28 vs. 20.45 ± 12.20 mm, p = 0.041) and greater divergent fracture angles (3.13 ± 1.97° vs. 1.40 ± 1.36°, p = 0.031). Regression modeling of the relationship between KE and fracture lengths and angles demonstrated that cubic followed by logarithmic regression models had the best fits. CONCLUSION: Osteotomy fracture patterns positively correlated with the mallet's KE more so than its p, suggesting that the mallet's velocity has an increased impact effect than its mass. Clinically, a heavier mallet with a lower velocity will likely generate a smaller fracture length and fracture angle, indicating a more controlled and ideal fracture. LEVEL OF EVIDENCE: NA Laryngoscope, 2024.

2.
Angew Chem Int Ed Engl ; : e202410112, 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-39016184

ABSTRACT

Axially chiral biaryls are ubiquitous scaffolds in natural products, bioactive molecules, chiral ligands and catalysts, but biocatalytic methods for their asymmetric synthesis are limited. Here, we report a highly efficient biocatalytic route for the atroposelective synthesis of biaryls via dynamic kinetic resolution (DKR). This DKR approach features a transient six-membered aza-acetal bridge-promoted racemization followed by an imine-reductase (IRED)-catalyzed stereoselective reduction to construct the axial chirality at ambient conditions. Directed evolution of an IRED from Streptomyces sp. GF3546 provided a variant (S-IRED-Ss-M11) capable of catalyzing the DKR process to access a variety of biaryl aminoalcohols in high yields and excellent enantioselectivities (up to 98% yield and >99:1 enantiomeric ratio). Molecular dynamics simulation studies on the S-IRED-Ss-M11 variant revealed the origin of its improved activity and atroposelectivity. By exploiting the substrate promiscuity of IREDs and the power of directed evolution, our work further extends the biocatalysts' toolbox to construct challenging axially chiral molecules.

3.
Int J Biol Macromol ; : 133912, 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-39025193

ABSTRACT

Gellan gum (GG) - the microbial exopolysaccharide is increasingly being adopted into drug development, tissue engineering, and food and pharmaceutical products. In spite of the commercial importance and expanding application horizon of GG, little attention has been directed toward the exploration of novel microbial cultures, development of advanced screening protocols, strain engineering, and robust upstream or downstream processes. This comprehensive review not only attempts to summarize the existing knowledge pool on GG bioprocess but also critically assesses their inherent challenges. The process optimization design augmented with advanced machine learning modeling tools, widely adopted in other microbial bioprocesses, should be extended to GG. The unification of mechanistic insight into data-driven modeling would help to formulate optimal feeding and process control strategies.

4.
J Biotechnol ; 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-39025369

ABSTRACT

The use of lignocellulosic biomass to create natural flavor has drawn attention from researchers. A key flavoring ingredient that is frequently utilized in the food industry is vanillin. In this present study, Pediococcus acidilactici PA VIT effectively involved in the production of bio-vanillin by using Ferulic acid as an intermediate with a yield of 11.43µg/ml. The bio-vanillin produced by Pediococcus acidilactici PA VIT was examined using FTIR, XRD, HPLC, and SEM techniques. These characterizations exhibited a unique fingerprinting signature like that of standard vanillin. Additionally, the one variable at a time method, placket Burmann method, and response surface approach, were employed to optimize bio-vanillin. Based on the central composite rotary design, the most important process factors were determined such as agitation speed, substrate concentration, and inoculum size. After optimization, bio-vanillin was found to have tenfold increase, with a maximum yield of 376.4µg/ml obtained using the response surface approach. The kinetic study was performed to analyze rate of reaction and effect of metal ions in the production of bio-vanillin showing Km of 10.25, and Vmax of 1250 were required for the reaction. The metal ions that enhance the yield of bio-vanillin are Ca2+, k+, and Mg2+ and the metal ions that affects the yield of bio-vanillin are Pb+ and Cr+ were identified from the effect of metal ions in the bio-vanillin production.

5.
J Mol Model ; 30(8): 262, 2024 Jul 11.
Article in English | MEDLINE | ID: mdl-38990414

ABSTRACT

CONTEXT: The debate over whether kinetic energy (KE) or potential energy (PE) are the fundamental energy components that contribute to forming covalent bonds has been enduring and stimulating over time. However, the supremacy of these energy components in reactions where multiple bonds are simultaneously formed or broken has yet to be explored. In this study, we use the reaction electronic flux (REF), an effective tool for investigating changes in driving electronic activity when bond formation or dissociation occurs in a chemical reaction, to examine the fluctuations in the KE and PE in a multi-bond reaction. To that end, the activation of CO 2 by low-valent group 14 catalysts through a concerted σ -bond metathesis mechanism is analyzed. The findings of this preliminary study suggest that the REF can be utilized as a tool to rationalize alterations in the KE and PE in a multi-bond reaction. Specifically, analyses across the reaction coordinate reveal that changes in the KE and PE precede activation in the REF, stimulating the electronic activity where bond formation or dissociation processes dominate. METHODS: The activation of CO 2 by the low-valent LEH catalysts (L = N,N'-bis(2,6-diisopropyl phenyl)- ß -diketiminate; E = Si, Ge, Sn, and Pb) was studied along the reaction coordinate at the M06-2X/6-31 G(d,p)-LANL2DZ(E) level of theory. The respective minimum energy path calculations were obtained using the intrinsic reaction coordinate (IRC) procedure. The reaction electronic flux (REF) was calculated through the computation of the electronic chemical potential using the frontier molecular orbital approximation. Mayer bond orders along the reaction coordinate have been determined using the NBO 3.1 program in Gaussian16. Most of the reaction coordinate quantities reported in this study (REF, KE, PE, among others) have been determined using the Kudi program and custom Python scripts.

6.
Angew Chem Int Ed Engl ; : e202407888, 2024 Jul 14.
Article in English | MEDLINE | ID: mdl-39003572

ABSTRACT

We showcase the successful combination of photochemistry and kinetic target-guided synthesis (KTGS) for rapidly pinpointing enzyme inhibitors. KTGS is a fragment-based drug discovery (FBDD) methodology in which the biological target (BT) orchestrates the construction of its own ligand from fragments featuring complementary reactive functionalities. Notably, fragments interacting with the protein binding sites leverage their spatial proximity, facilitating a preferential reaction. Consequently, the resulting bivalent ligand exhibits heightened affinity. Within the realm of KTGS strategies, in situ click chemistry stands out as the most widely used to identify potent protein binders. This approach requires significant protein contributions, such as binding interactions and appropriate orientations of fragments, to overcome high activation barriers. This leads to prolonged incubation times and the potential for generating false negatives, thereby limiting this strategy to proteins that are stable enough in buffer. We herein unveil the possibility to integrate photochemistry into the realm of KTGS, accelerating the ligation reaction between fragments to a time scale of minutes. This approach should significantly expand the narrow reactivity window of traditional KTGS reactions, paving the way for the exploration and development of novel photo-KTGS reactions.

7.
J Environ Manage ; 366: 121706, 2024 Jul 08.
Article in English | MEDLINE | ID: mdl-38981270

ABSTRACT

Recycling waste Ni-Cd batteries has received much attention recently because of the serious environmental pollution they cause and to avoid the dissipation of valuable metals. Despite significant research, it is still difficult to efficiently recycle valuable and hazardous metals from waste Ni-Cd batteries in an economical and environmentally friendly manner. This study employed a novel process utilizing ultrasound-assisted leaching to recover Ni, Cd, and Co from waste nickel-cadmium (Ni-Cd) batteries. Organic DL-malic acid served as the leaching agent and H2O2 was employed as an oxidizing agent. The effects of various factors on the recovery efficiency of Ni, Cd, and Co, such as leaching temperature, time, DL-malic acid concentration, pulp density, H2O2 concentration, and ultrasound frequency, were also examined. To predict the chemical compounds present before and after the recycling experiments, the solid residues from the metal extraction were analyzed using XRD, XPS, FE-SEM, and EDS element mapping. Concurrently, ICP-OES was utilized to determine the metal content in the leachate. Under optimized conditions of 90 °C, 90 min, 2M DL-malic acid, 160 mL/g pulp density, and 20% ultrasound frequency, over 83% of Ni, 94% of Cd, and 98% of Co were effectively leached from the waste Ni-Cd battery powder. The leaching kinetics of Ni, Cd, and Co followed the surface chemical reaction control model. The activation energies (Ea) for Ni, Cd, and Co leaching were 21.34, 20.47, and 18.38 kJ/mol, respectively. The findings suggest that ultrasound-assisted leaching is an efficient, cost-effective, environmentally friendly, and sustainable alternative for extracting precious and hazardous metals from waste Ni-Cd batteries. Additionally, it reduces industrial chemical usage and enhances waste management sustainability.

8.
Environ Geochem Health ; 46(9): 308, 2024 Jul 13.
Article in English | MEDLINE | ID: mdl-39001890

ABSTRACT

This study introduces a new biosorbent derived from Delonix regia bark-activated carbon to efficiently remove Chromium Cr(VI) metal ions from aqueous systems. The biosorbent was synthesized from the bark powder of the plant species and chemically activated with phosphoric acid. The biosorbent was characterized using FTIR, SEM, and BET to determine its functional properties and structural morphology. The batch adsorption experiments examined the optimal conditions for Cr(VI) metal ion adsorption, identifying that the highest removal efficiency occurred at pH levels of 2. The ideal adsorbent dosage was determined to be 2.5 g/L, with equilibrium achieved at a contact time of 60 min at the optimal temperature of about 303 K for a Cr(VI) metal ion concentration of 20 mg/L. Various isotherm models were applied to the adsorption equilibrium values, revealing that the adsorbent had a maximum removal capacity of approximately 224.8 mg/g for Cr(VI) metal ions. The adsorption process of Cr(VI) on the DAC biosorbent was best described by the Freundlich isotherm, indicating multilayer adsorption. The kinetic data fit well with the pseudo-second-order model. Thermodynamic parameters suggested that the adsorption process was spontaneous, exothermic, and feasible across different temperatures. Furthermore, the desorption studies showed that the DAC biosorbent can easily be rejuvenated and utilized several cycles with high adsorption capacity. These findings indicate that the developed adsorbent is environmentally friendly and effective for removing Cr(VI) from water systems.


Subject(s)
Charcoal , Chromium , Plant Bark , Water Pollutants, Chemical , Chromium/chemistry , Adsorption , Plant Bark/chemistry , Water Pollutants, Chemical/chemistry , Charcoal/chemistry , Hydrogen-Ion Concentration , Water Purification/methods , Kinetics , Sapotaceae/chemistry , Thermodynamics , Spectroscopy, Fourier Transform Infrared , Temperature
9.
Biotechnol Lett ; 2024 Jul 13.
Article in English | MEDLINE | ID: mdl-39002086

ABSTRACT

PURPOSE: Fed-batch cultures have rarely been used in single cell protein (SCP) research. This work evaluated multiple yeast species for suitability as SCP cultivated using glucose- and sucrose-based substrate and performed in-depth studies of fed-batch SCP cultivation kinetics for selected yeasts, including determination of specific crude nitrogen-to-protein conversion factors. METHODS: SCP was cultivated using fully synthetic media in flask batch or bioreactor fed-batch cultures. Crude nitrogen and nucleic acid content were determined using the Dumas method and fluorescence assay kits, respectively. RESULTS: C. utilis compared favorably to other yeasts in flask batch cultures in terms of process yield (0.52 ± 0.01 gx gs-1) and crude nitrogen content (10.0 ± 0.5 and 9.9 ± 0.5%CDW for glucose and sucrose, respectively). This is the first time biomass composition data was reported for SCP cultivated in fed-batch mode. C. utilis crude nitrogen content was consistent across the tested conditions (protein content stabilized around 50%CDW in fed-batch), while that of the benchmark yeast S. cerevisiae was higher in batch cultures and at the beginning of fed-batch relative to the end (protein content decreased over time and stabilized around 43%CDW). Total nucleic acid content of the yeasts was similar (6.8%CDW and 6.3%CDW, for C. utilis and S. cerevisiae, respectively), with crude nitrogen-to-protein conversion factors of 4.97 and 5.80. CONCLUSION: This study demonstrated the suitability of C. utilis as SCP, notably the robustness of its crude nitrogen content (as an indicator of protein content) across batch and fed-batch conditions, compared to that of the benchmark yeast S. cerevisiae.

10.
Phys Life Rev ; 50: 72-97, 2024 Jul 06.
Article in English | MEDLINE | ID: mdl-39002422

ABSTRACT

In the last decade, the thermostatted kinetic theory has been proposed as a general paradigm for the modeling of complex systems of the active matter and, in particular, in biology. Homogeneous and inhomogeneous frameworks of the thermostatted kinetic theory have been employed for modeling phenomena that are the result of interactions among the elements, called active particles, composing the system. Functional subsystems contain heterogeneous active particles that are able to perform the same task, called activity. Active matter living systems usually operate out-of-equilibrium; accordingly, a mathematical thermostat is introduced in order to regulate the fluctuations of the activity of particles. The time evolution of the functional subsystems is obtained by introducing the conservative and the nonconservative interactions which represent activity-transition, natural birth/death, induced proliferation/destruction, and mutation of the active particles. This review paper is divided in two parts: In the first part the review deals with the mathematical frameworks of the thermostatted kinetic theory that can be found in the literature of the last decade and a unified approach is proposed; the second part of the review is devoted to the specific mathematical models derived within the thermostatted kinetic theory presented in the last decade for complex biological systems, such as wound healing diseases, the recognition process and the learning dynamics of the human immune system, the hiding-learning dynamics and the immunoediting process occurring during the cancer-immune system competition. Future research perspectives are discussed from the theoretical and application viewpoints, which suggest the important interplay among the different scholars of the applied sciences and the desire of a multidisciplinary approach or rather a theory for the modeling of every active matter system.

11.
Bioresour Technol ; : 131076, 2024 Jul 11.
Article in English | MEDLINE | ID: mdl-39002885

ABSTRACT

Syngas and CO-rich off-gases are key chemical platforms to produce biofuels and bioproducts. From the perspective of optimizing and up-scaling CO co-digestion with organic waste streams, this study aims at assessing and quantifying the inhibitory effects of CO on acidogenic glucose fermentation and aceticlastic methanogenesis. Mesophilic cultures were fed in two sets of batch assays, respectively, with glucose and acetate while being exposed to dissolved CO in equilibrium with partial pressures in the range of 0.25-1.00 atm. Cumulative methane production and microbial monitoring revealed that aceticlastic methanogenic archaea were significantly inhibited (2-20 % of the methane production of CO non-exposed cultures). The acidogenic glucose degrading community was also inhibited by CO, although, thanks to its functional redundancy, shifted its metabolism towards propionate production. Future work should assess the sensitivity of hereby estimated CO inhibition parameters, e.g., on the simulation output of a continuous syngas co-digestion process with organic substrates.

12.
Sensors (Basel) ; 24(13)2024 Jun 29.
Article in English | MEDLINE | ID: mdl-39001027

ABSTRACT

Remote patient-monitoring systems are helpful since they can provide timely and effective healthcare facilities. Such online telemedicine is usually achieved with the help of sophisticated and advanced wearable sensor technologies. The modern type of wearable connected devices enable the monitoring of vital sign parameters such as: heart rate variability (HRV) also known as electrocardiogram (ECG), blood pressure (BLP), Respiratory rate and body temperature, blood pressure (BLP), respiratory rate, and body temperature. The ubiquitous problem of wearable devices is their power demand for signal transmission; such devices require frequent battery charging, which causes serious limitations to the continuous monitoring of vital data. To overcome this, the current study provides a primary report on collecting kinetic energy from daily human activities for monitoring vital human signs. The harvested energy is used to sustain the battery autonomy of wearable devices, which allows for a longer monitoring time of vital data. This study proposes a novel type of stress- or exercise-monitoring ECG device based on a microcontroller (PIC18F4550) and a Wi-Fi device (ESP8266), which is cost-effective and enables real-time monitoring of heart rate in the cloud during normal daily activities. In order to achieve both portability and maximum power, the harvester has a small structure and low friction. Neodymium magnets were chosen for their high magnetic strength, versatility, and compact size. Due to the non-linear magnetic force interaction of the magnets, the non-linear part of the dynamic equation has an inverse quadratic form. Electromechanical damping is considered in this study, and the quadratic non-linearity is approximated using MacLaurin expansion, which enables us to find the law of motion for general case studies using classical methods for dynamic equations and the suitable parameters for the harvester. The oscillations are enabled by applying an initial force, and there is a loss of energy due to the electromechanical damping. A typical numerical application is computed with Matlab 2015 software, and an ODE45 solver is used to verify the accuracy of the method.


Subject(s)
Electrocardiography , Heart Rate , Wearable Electronic Devices , Heart Rate/physiology , Humans , Monitoring, Physiologic/instrumentation , Monitoring, Physiologic/methods , Electrocardiography/methods , Electrocardiography/instrumentation , Electric Power Supplies , Internet of Things , Kinetics , Telemedicine/instrumentation
13.
Biophys Chem ; 313: 107293, 2024 Jul 10.
Article in English | MEDLINE | ID: mdl-39004034

ABSTRACT

The secondary amyloidosis of humans is caused by the formation of hSAA fibrils in different organs and tissues. Until now hSAA was thought to have low amyloidogenicity in vitro and the majority of SAA aggregation experiments were done using murine protein or hSAA non-pathogenic isoforms. In this work a novel purification method for recombinant hSAA was introduced, enabling to obtain monomeric protein capable of amyloid aggregation under physiological conditions. The stability and amyloid aggregation of hSAA have been examined using a wide range of biophysical methods. It was shown that the unfolding of monomeric protein occurs through the formation of molten globule-like intermediate state. Polymorphism of hSAA amyloids was discovered to depend on the solution pH. At pH 8.5, rapid protein aggregation occurs, which leads to the formation of twisted short fibrils. Even a slight decrease of the pH to 7.8 results in delayed aggregation with the formation of long straight amyloids composed of laterally associated protofilaments. Limited proteolysis experiments have shown that full-length hSAA is involved in the formation of intermolecular interactions in both amyloid polymorphs. The results obtained, and the experimental approach used in this study can serve as a basis for further research on the mechanism of authentic hSAA amyloid formation.

14.
Int J Biol Macromol ; : 133850, 2024 Jul 12.
Article in English | MEDLINE | ID: mdl-39004259

ABSTRACT

The interaction between genipin and a model protein bovine serum albumin (BSA), with and without the addition of acetic acid, has been studied experimentally and by modelling. The number of amino groups available to react was determined to be 5.6 % of the total number of amino acid building blocks on BSA. Fluorescence intensity was used to record the progress of the reaction over the 24 h, while the modelling study focused on capturing the kinetic profiles of the reaction. The experiments revealed a slow start to the BSA and genipin interaction, that subsequently accelerated in an S-shaped curve which the modelling study linked with the existence of the feedback cycle for both reactive amino groups and genipin. At BSA concentrations ≥30 mg/mL the reaction was accelerated in the presence of acid, while below 30 mg/mL the acidified conditions delayed the onset of the reaction. Contrary to the reaction mechanisms previously proposed, a degree of breakdown of the fluorescent links in the products formed was denoted both experimentally and in a modelling study. This indicated the reversibility of the processes forming fluorescent product/s and suggested feasibility of the successful release of the protein following prospective encapsulation within the genipin-crosslinked hydrogel structure.

15.
EJNMMI Phys ; 11(1): 56, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38951271

ABSTRACT

BACKGROUND: Multiplexed positron emission tomography (mPET) imaging can measure physiological and pathological information from different tracers simultaneously in a single scan. Separation of the multiplexed PET signals within a single PET scan is challenging due to the fact that each tracer gives rise to indistinguishable 511 keV photon pairs, and thus no unique energy information for differentiating the source of each photon pair. METHODS: Recently, many applications of deep learning for mPET image separation have been concentrated on pure data-driven methods, e.g., training a neural network to separate mPET images into single-tracer dynamic/static images. These methods use over-parameterized networks with only a very weak inductive prior. In this work, we improve the inductive prior of the deep network by incorporating a general kinetic model based on spectral analysis. The model is incorporated, along with deep networks, into an unrolled image-space version of an iterative fully 4D PET reconstruction algorithm. RESULTS: The performance of the proposed method was evaluated on a simulated brain image dataset for dual-tracer [ 18 F]FDG+[ 11 C]MET PET image separation. The results demonstrate that the proposed method can achieve separation performance comparable to that obtained with single-tracer imaging. In addition, the proposed method outperformed the model-based separation methods (the conventional voxel-wise multi-tracer compartment modeling method (v-MTCM) and the image-space dual-tracer version of the fully 4D PET image reconstruction algorithm (IS-F4D)), as well as a pure data-driven separation [using a convolutional encoder-decoder (CED)], with fewer training examples. CONCLUSIONS: This work proposes a kinetic model-informed unrolled deep learning method for mPET image separation. In simulation studies, the method proved able to outperform both the conventional v-MTCM method and a pure data-driven CED with less training data.

16.
Front Oncol ; 14: 1380793, 2024.
Article in English | MEDLINE | ID: mdl-38947892

ABSTRACT

Glioma is the most common type of primary malignant tumor of the central nervous system (CNS), and is characterized by high malignancy, high recurrence rate and poor survival. Conventional imaging techniques only provide information regarding the anatomical location, morphological characteristics, and enhancement patterns. In contrast, advanced imaging techniques such as dynamic contrast-enhanced (DCE) MRI or DCE CT can reflect tissue microcirculation, including tumor vascular hyperplasia and vessel permeability. Although several studies have used DCE imaging to evaluate gliomas, the results of data analysis using conventional tracer kinetic models (TKMs) such as Tofts or extended-Tofts model (ETM) have been ambiguous. More advanced models such as Brix's conventional two-compartment model (Brix), tissue homogeneity model (TH) and distributed parameter (DP) model have been developed, but their application in clinical trials has been limited. This review attempts to appraise issues on glioma studies using conventional TKMs, such as Tofts or ETM model, highlight advancement of DCE imaging techniques and provides insights on the clinical value of glioma management using more advanced TKMs.

17.
Environ Res ; : 119548, 2024 Jul 06.
Article in English | MEDLINE | ID: mdl-38977156

ABSTRACT

The term "biomass" encompasses all substances found in the natural world that were once alive or derived from living organisms or their byproducts. These substances consist of organic molecules containing hydrogen, typically oxygen, frequently nitrogen, and small amounts of heavy, alkaline earth and alkali metals. Magnetic biochar refers to a type of material derived from biomass that has been magnetized typically by adding magnetic components such as magnetic iron oxides to display magnetic properties. These materials are extensively applicable in widespread areas like environmental remediation and catalysis. The magnetic properties of these compounds made them ideal for practical applications through their easy separation from a reaction mixture or environmental sample by applying a magnetic field. With the evolving global strategy focused on protecting the planet and moving towards a circular, cost-effective economy, natural compounds, and biomass have become particularly important in the field of biochemistry. The current research explores a comparative analysis of the versatility and potential of biomass for eliminating dyes as a sustainable, economical, easy, compatible, and biodegradable method. The elimination study focused on the removal of various dyes as pollutants. Various operational parameters which influenced the dye removal process were also discussed. Furthermore, the research explained, in detail, adsorption kinetic models, types of isotherms, and desorption properties of magnetic biochar adsorbents. This comprehensive review offers an advanced framework for the effective use of magnetic biochar, removing dyes from textile wastewater.

18.
Chemistry ; : e202400331, 2024 Jul 08.
Article in English | MEDLINE | ID: mdl-38977407

ABSTRACT

L-Idose thioglycosides are useful glycosyl donors for the construction of glycosaminoglycan oligosaccharides. When activated with NIS and catalytic TMSOTf in the presence of methanol, the stereoselectivity of O-glycosylation displays an intriguing dependence on the reaction temperature, with an increased preference for formation of the α-glycoside at higher temperatures. Using a combination of vt-NMR spectroscopy and DFT calculations, we show how a simple mechanistic model, based on competing reactions of the iodinated thioglycoside, can explain the main features of the temperature dependence. In this model, the increased selectivity at high temperature is attributed to differences among the entropy and energy terms of the competing reaction pathways. Neighbouring-group participation (giving an intermediate acyloxonium ion) plays an increasingly dominant role as temperature is raised. The general features of this kinetic regime may also apply more broadly to other glycosylations that likewise favour α-glycoside formation at high temperature.

19.
Environ Sci Technol ; 2024 Jul 10.
Article in English | MEDLINE | ID: mdl-38986049

ABSTRACT

Pd-based electrodes are recognized to facilitate effective electrochemical hydrodechlorination (EHDC) as a result of their superior capacity for atomic hydrogen (H*) generation. However, challenges such as electrode stability, feasibility of treating complex matrices, and high cost associated with electrode synthesis hinder the application of Pd-based electrodes for EHDC. In this work, we investigated the feasibility of degrading 2,4-dichlorophenol (2,4-DCP) by EHDC employing Pd-loaded activated carbon particles, prepared via a simple wet-impregnation method, as a flow cathode (FC) suspension. Compared to other Pd-based EHDC studies, a much lower Pd loading (0.02-0.08 mg cm-2) was used. Because of the excellent mass transfer in the FC system, almost 100% 2,4-DCP was hydrodechlorinated to phenol within 1 h. The FC system also showed excellent performance in treating complex water matrices (including hardness ion-containing wastewater and various other chlorinated organics such as 2,4-dichlorobenzoic acid and trichloroacetic acid) with a relatively low energy consumption (0.26-1.56 kW h m-3 mg-1 of 2,4-DCP compared to 0.32-7.61 kW h m-3 mg-1 of 2,4-DCP reported by other studies). The FC synthesized here was stable over 36 h of continuous operation, indicating its potential suitability for real-world applications. Employing experimental investigations and mathematical modeling, we further show that hydrodechlorination of 2,4-DCP occurs via interaction with H*, with no role of direct electron transfer and/or HO•-mediated processes in the removal of 2,4-DCP.

20.
Sports Biomech ; : 1-17, 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-38979762

ABSTRACT

The Force-velocity (F-v) and Power-velocity (P-v) relationships quantify athlete's horizontal force production capacities during sprinting. Efforts are underway to enhance ecological validity for practitioners and sports coaches. This study provides detailed data comparison of a low frames per second setup (30 Hz; FPSlow) with splits from a high FPS camera to derive F-v and P-v relationships. Sixty-six sprints performed by 11 university track and field athletes (6 male, 5 female) were evaluated. Data were recorded using FPSlow, photocells, and a high-speed camera (240 Hz; MySprint). In the FPSlow setup, bias was 0.17s, and Limits of agreement was 0.09s compared to photocells. ICC was 1.00, and the coefficient of variation (CV) was 1.0% [0.8-1.1%]. Time acquisition comparison between MySprint and FPSlow setups revealed high consistency (ICC = 0.99) and low CV (2.9% [2.8-3.1%]). F-v profile variables exhibited biases from trivial to small, with ICC ranging from moderate to nearly perfect. CV ranged from 2.7% to 11.8%, and improved using the average of three sprints (CV between 1.8% and 8.6%). The 'simple method' applied to data from the low FPS video setup yielded kinetic and kinematic parameters comparable to those obtained by the validated previous method and photocells.

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