A Generalized-Rate Model for Describing and Scaling Redox Kinetics in Sediments Containing Variable Redox-Reactive Materials

This study developed a generalized modeling approach for describing and scaling redox reactions from reactive components to the sediments and their assemblages, using Cr­(VI) reduction as an example. Batch experiments were performed to characterize the rates of Cr­(VI) reduction in four Fe­(II)-containing sediments and their assemblages. The experimental data were first used to calibrate a generalized-rate model of Cr­(VI) reduction with generic rate parameters. The generalized-rate model was then used to describe the kinetics of Cr­(VI) reduction in the sediment assemblages by linearly scaling the rate parameters from the individual sediments. Via comparison with the experimental results, this study found that the generalized-rate model with generic rate parameters can describe Cr­(VI) reduction in individual sediments and their assemblages with different redox reactivity toward Cr­(VI) reduction. The sediment-associated Fe­(II) and its reactivity were found to be the key variables in the generalized model for describing the Cr­(VI) reduction in the studied sediments. A three-step extraction method was subsequently developed to estimate the rate-specific Fe­(II) pools that can facilitate the application of the scaling approach in field systems

Coupled Hydro-Biogeochemical Processes Controlling Cr Reductive Immobilization in Columbia River Hyporheic Zone

An experiment and modeling study was conducted to investigate coupled hydro-biogeochemical processes controlling reductive immobilization of groundwater Cr in the hyporheic zone (HZ) at the U.S. Department of Energy’s Hanford Site, where dynamic surface water–groundwater exchange occurs on a daily basis. Experiments were performed to calibrate kinetic models, and the calibrated models were incorporated into a multicomponent reactive transport model to simulate Cr redox transformation and immobilization under field hydrological conditions. The results revealed that the rates of Cr­(VI) reduction, Cr­(III) accumulation, and Cr­(VI) release to the river are mostly affected by dynamic sediment redox conditions represented by Fe­(II) reactivity, which is controlled by its cyclic interaction with O₂ carried by river water, microbial activities, and the supply and bioavailability of organic carbon (OC) that is present in the HZ and/or carried by transport. In addition, the HZ geophysical properties including hydraulic conductivity and the thickness of the top alluvial layer have a significant influence on Cr reactive transport and immobilization by controlling residence times for reactions and the supply rates of O₂, Cr, and OC into the HZ. The results provide important insights into the dynamic redox environments in the HZ that can reductively immobilize contaminants

Top-down (LTQ-FT ICR) MS modification analysis of various TSP-1 EGF-like (E) modules.

<p>(A) Sequences of the three TSP-1 EGF-like modules are compared. Only E1 contains the O-GlcNAc modification consensus sequence. (B) LTQ-FT ICR MS performed on the TSP-1 E1 module demonstrating modifications in relation to the unmodified precursor size (6096.74-Da). Known Glc (+162-Da) and Xyl (+132-Da) modifications were detected, along with the HexNAc (+203-Da) modification (summed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032762#pone-0032762-t001" target="_blank">Table 1</a>). (C) Low energy (q = 7) collision-induced dissociation was then performed on the 6593.93-Da E1 module peak containing Glc, Xyl, and HexNAc from (B) to see if modifications were removed separately. Top-down MS analysis was performed on (D) E2 and (E) E3 modules for comparison.</p

Mechanism of Asymmetric Hydrogenation of β‑Dehydroamino Acids Catalyzed by Rhodium Complexes: Large-Scale Experimental and Computational Study

The mechanism of asymmetric hydrogenation of five representative β-dehydroamino acids catalyzed by rhodium complexes of (<i>R</i>)-(<i>tert</i>-butylmethylphosphino)­(di-<i>tert</i>-butylphosphino)­methane (trichickenfootphos, TCFP) and (<i>R</i>,<i>R</i>)-1,2-bis­(<i>tert</i>-butylmethylphosphino)­benzene (BenzP*) was studied through a combination of extensive NMR experiments and state-of-the-art DFT computations in order to reveal the crucial factors governing the sense and order of enantioselectivity in this industrially important reaction. The binding mode of the substrate with a Rh­(I) catalyst was found to be highly dependent on the nature of the rhodium complex and the substrate. Thus, no substrate binding was detected for [Rh­((<i>R</i>,<i>R</i>)-BenzP*)­S₂]⁺SbF₆^– (<b>5</b>) and (<i>E</i>)-3-acetylamino-2-butenoate (<b>2a</b>) even at 173 K. [Rh­((<i>R</i>)-TCFP) S₂]⁺BF₄^– (<b>3</b>) exhibited weak reversible binding with <b>2a</b> in the temperature interval 173–253 K with the formation of complex <b>4a</b>, whereas at ambient temperature, slow isomerization of <b>2a</b> to (<i>Z</i>)-3-acetylamino-2-butenoate (<b>2b</b>) took place. The investigations with a total of 10 combinations of the catalysts and substrates demonstrated various binding modes that did not affect significantly the enantioselectivities observed in corresponding catalytic reactions and in low temperature hydrogenations of the catalyst–substrate complexes. The monohydride intermediate <b>10</b> formed quantitatively when the equilibrium mixture of <b>2a</b>, <b>3</b>, and <b>4a</b> was hydrogenated at 173 K. Its molecular structure including relative stereochemistry was determined by NMR experiments. These results together with the stereochemichal outcome of the low-temperature hydrogenation (99.2% ee, <i>R</i>) and DFT calculations led to the reasonable reaction pathway of the asymmetric hydrogenation of <b>2a</b> catalyzed by <b>3</b>. The conceivable catalytic pathways were computed for five combinations of the BenzP*-Rh catalyst and prochiral β-dehydroamino acids <b>2a,b</b> and <b>21</b>–<b>23</b>. In most cases, it was found that the pathways involving the hydrogenation of Rh­(I) square planar chelate complexes are usually higher in free energy than the pathways with the hydrogen activation prior to the chelate formation. Computed differences in the free energies of the transition states for the double bond coordination stage of the <i>R</i> and <i>S </i>pathways reasonably well reproduce the optical yields observed experimentally in the corresponding catalytic reactions and in the low temperature hydrogenation experiments. To explain extremely high ee’s (>99% ee) in some of the hydrogenations, it is necessary to analyze in more detail the participation of the solvent in the enantiodetermining step

MALDI-TOF/TOF sequencing of O-β-GlcNAc-modified tryptic peptide of the TSP-1 E1 module.

<p>The MALDI-TOF spectrum is indicated in (A) with both the −GlcNAc (2407.1-Da) and +GlcNAc (2610.2-Da) E1 module tryptic peptide peaks indicated. The MALDI-TOF/TOF y+1 ion series detected and spectrum are indicated in (B). Note the modification of Ser580 by O-β-GlcNAc from the difference between y₁₃ and y₁₄ ions. Also, note loss of a +203-Da adduct from a portion of the 2610.2-Da isolated peak and reversion to the unmodified peak as indicated.</p

Datasheet1_Efficacy and safety of levetiracetam vs. oxcarbazepine in the treatment of children with epilepsy: a systematic review and meta-analysis.csv

BackgroundLevetiracetam (LEV) and oxcarbazepine (OXC) are new antiseizure medications (ASMs). In recent years, OXC monotherapy is widely used in children with epilepsy; however, no consensus exists on applying LEV monotherapy among children with epilepsy.ObjectiveThe present work focused on comparing the efficacy and safety of LEV and OXC monotherapy in treating children with epilepsy.MethodsWe conducted a comprehensive search across multiple databases including PubMed, Cochrane Library, Embase, Web of Science, CNKI, Wanfang Database, VIP, and China Biology Medicine disc, covering studies from inception to August 26, 2023. We included randomized controlled trials (RCTs) and cohort studies evaluating the efficacy and safety of LEV and OXC monotherapy for treating epilepsy in children. We utilized Cochrane Risk of Bias Tool in RevMan 5.3 software for assessing included RCTs quality. In addition, included cohort studies quality was determined using Newcastle-Ottawa Scale (NOS). A random-effects model was utilized to summarize the results.ResultsThis meta-analysis included altogether 14 studies, including 893 children with epilepsy. LEV and OXC monotherapy was not statistical different among children with epilepsy in seizure-free rate (relative risk [RR] = 1.010, 95% confidence interval [CI] [0.822, 1.242], P > 0.05) and seizure frequency decrease of ≥50% compared with baseline [RR = 0.938, 95% CI (0.676, 1.301), P > 0.05]. Differences in total adverse reaction rate [RR = 1.113, 95% CI (0.710, 1.744), P > 0.05] and failure rate because of serious adverse reaction [RR = 1.001, 95% CI (0.349, 2.871), P > 0.05] were not statistical different between LEV and OXC treatments among children with epilepsy. However, the effects of OXC monotherapy on thyroid among children with epilepsy was statistically correlated than that of LEV (thyroid stimulating hormone: standardized mean difference [SMD] = −0.144, 95% CI [−0.613, 0.325], P > 0.05; free thyroxine: SMD = 1.663, 95% CI [0.179, 3.147], P ConclusionThe efficacy of LEV and OXC monotherapy in treating children with epilepsy is similar. However, OXC having a more significant effect on the thyroid than that of LEV. Therefore, LEV may be safer for children with epilepsy who are predisposed to thyroid disease than OXC.Systematic Review Registrationhttps://www.crd.york.ac.uk/, PROSPERO (CRD42024514016)</p

Potential sites of O-β-GlcNAc modification between the fifth and sixth cysteines of EGF-like modules (E) of human proteins.

<p>The sequence between the fifth and sixth cysteines of the 20^th EGF-like module of <i>Drosophila</i> Notch was used as bait in a BLAST search of the human UniProtKB database. The number of the module among the EGF-like modules in a given protein is based on UniProtKB's annotation of the human protein sequences. The E1 module of TSP-2 is also given and discussed in the text.</p

LTQ-FT ICR MS quantification of TSP-1 E1 module modifications (Figure 4B).

<p>Glc indicates glucose; Xyl indicates xylose; HexNAc indicates glucosamine modification.</p

Datasheet2_Efficacy and safety of levetiracetam vs. oxcarbazepine in the treatment of children with epilepsy: a systematic review and meta-analysis.pdf

BackgroundLevetiracetam (LEV) and oxcarbazepine (OXC) are new antiseizure medications (ASMs). In recent years, OXC monotherapy is widely used in children with epilepsy; however, no consensus exists on applying LEV monotherapy among children with epilepsy.ObjectiveThe present work focused on comparing the efficacy and safety of LEV and OXC monotherapy in treating children with epilepsy.MethodsWe conducted a comprehensive search across multiple databases including PubMed, Cochrane Library, Embase, Web of Science, CNKI, Wanfang Database, VIP, and China Biology Medicine disc, covering studies from inception to August 26, 2023. We included randomized controlled trials (RCTs) and cohort studies evaluating the efficacy and safety of LEV and OXC monotherapy for treating epilepsy in children. We utilized Cochrane Risk of Bias Tool in RevMan 5.3 software for assessing included RCTs quality. In addition, included cohort studies quality was determined using Newcastle-Ottawa Scale (NOS). A random-effects model was utilized to summarize the results.ResultsThis meta-analysis included altogether 14 studies, including 893 children with epilepsy. LEV and OXC monotherapy was not statistical different among children with epilepsy in seizure-free rate (relative risk [RR] = 1.010, 95% confidence interval [CI] [0.822, 1.242], P > 0.05) and seizure frequency decrease of ≥50% compared with baseline [RR = 0.938, 95% CI (0.676, 1.301), P > 0.05]. Differences in total adverse reaction rate [RR = 1.113, 95% CI (0.710, 1.744), P > 0.05] and failure rate because of serious adverse reaction [RR = 1.001, 95% CI (0.349, 2.871), P > 0.05] were not statistical different between LEV and OXC treatments among children with epilepsy. However, the effects of OXC monotherapy on thyroid among children with epilepsy was statistically correlated than that of LEV (thyroid stimulating hormone: standardized mean difference [SMD] = −0.144, 95% CI [−0.613, 0.325], P > 0.05; free thyroxine: SMD = 1.663, 95% CI [0.179, 3.147], P ConclusionThe efficacy of LEV and OXC monotherapy in treating children with epilepsy is similar. However, OXC having a more significant effect on the thyroid than that of LEV. Therefore, LEV may be safer for children with epilepsy who are predisposed to thyroid disease than OXC.Systematic Review Registrationhttps://www.crd.york.ac.uk/, PROSPERO (CRD42024514016)</p

Schematic diagram of Group A TSPs modular composition.

<p>Group A TSPs, TSP-1 and -2, are trimeric, multi-modular calcium-binding proteins. The subunit comprises a N-terminal module (N), oligomerization sequence (o), von Willebrand Factor C module (C), three properdin-like modules (P123), three EGF-like modules (E123), a calcium-binding wire (Ca), and a globular lectin-like C-terminal module (G).</p