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To improve the thermodynamic and mechanical properties of asymmetric polyimide (PI), a method to enhance the linearity of PI by using a structural reorganization approach was designed. First, two novel diamines containing benzimidazole and benzoxazole groups, namely PADBZ and PDBOA, were constructed and synthesized. Thereafter, two new kinds of PI films (PADBZ‐PMDA and PDBOA‐PMDA) were prepared and polymerized with 1,2,4,5‐benzenetetracarboxylic anhydride (PMDA). Based on structural reorganization, PADBZ‐PMDA and PDBOA‐PMDA had repeating units of the same chemical composition and different linearity with PABZ‐BPDA and BOA‐BPDA, respectively. Comparing PADBZ‐PMDA and PABZ‐BPDA, due to the transfer in the position of benzene, PADBZ‐PMDA with high linearity showed the improved heat resistance (Tg up to 448°C), dimensional stability (CTE down to 2.3 ppm/K) and mechanical properties. PDBOA‐PMDA and BOA‐BPDA had the same situation. This study provided a unique solution to enhance the performances of PI by increasing the linearity using a structural reorganization approach. [ABSTRACT FROM AUTHOR]

Shape-selective stannosilicates have been post-synthesized for the hydration of epoxide to diols. A simple acid treatment has been employed to remove extensively the interlayer double four ring units, converting the three-dimensional (3D) UTL germanosilicate into a 2D layered IPC-1P intermediate. Isomorphous incorporation of tetrahedrally coordinated Sn active centers was realized via solid-liquid treatment of IPC-1P with diammonium hexachlorostannate aqueous solution, which was accompanied by the spontaneous condensation of neighboring silica-rich cfi layers upon calcination and structural construction of a 3D PCR structure. Sn-PCR stannosilicates with tunable Sn contents were thus prepared. With Sn-derived robust Lewis acidity confined in the intersecting 10- and 8-ring channels, the Sn-PCR (Si/Sn molar ratio of 77) catalyst served as a shape-selective nanoreactor for the hydration of ethylene oxide (EO) into ethylene glycol (EG), exhibiting a remarkable EO conversion (99.5 %) as well as a steady EG selectivity (>98.4 %) at greatly reduced H2 O/EO molar ratio and near-ambient reaction temperature. [ABSTRACT FROM AUTHOR]

The current dogma to explain the extent of injury-related changes following rodent controlled cortical impact (CCI) injury is a focal injury with limited axonal pathology. However, there is in fact good, published histologic evidence to suggest that axonal injury is far more widespread in this model than generally thought. One possibility that might help to explain this is the often-used region-of-interest data analysis approach taken by experimental traumatic brain injury (TBI) diffusion tensor imaging (DTI) or histologic studies that might miss more widespread damage, when compared to the whole brain, statistically robust method of tract-based analysis used more routinely in clinical research. To determine the extent of DTI changes in this model, we acquired in vivo DTI data before and at 1 and 4weeks after CCI injury in 17 adult male rats and analyzed parametric maps of fractional anisotropy (FA), axial, radial, and mean diffusivity (AD, RD, MD), tensor mode (MO), and fiber tract density (FTD) using tract-based spatial statistics. Contusion volume was used as a surrogate marker of injury severity and as a covariate for investigating severity dependence of the data. Mean fiber tract length was also computed from seeds in the cortical spinal tract regions. In parallel experiments (n=3-5/group), we investigated corpus callosum neurofilaments and demyelination using immunohistochemistry (IHC) at 3days and 6weeks, callosal tract patency using dual-label retrograde tract tracing at 5weeks, and the contribution of gliosis to DTI parameter maps using GFAP IHC at 4weeks post-injury. The data show widespread ipsilateral regions of significantly reduced FA at 1week post-injury, driven by temporally changing values of AD, RD, and MD that persist to 4weeks. Demyelination, retrograde label tract loss, and reductions in MO (tract degeneration) and FTD were shown to underpin these data. Significant FA increases occurred in subcortical and corticospinal tract regions that were spatially distinct from regions of FA decrease, grossly affected gliotic areas, and MO changes. However, there was good spatial correspondence between regions of increased FA and areas of increased FTD and mean fiber length. We discuss these widespread changes in DTI parameters in terms of axonal degeneration and potential reorganization, with reference to a resting state fMRI companion paper (Harris et al., 2016, Exp. Neurol. 227:124-138) that demonstrated altered functional connectivity data acquired from the same rats used in this study.

Objectives: To investigate whether patients with overactive bladder syndrome (OAB) have brain volume changes using voxel-based morphometry (VBM) and correlations with clinical tests. Methods: With institutional review board approval and after obtaining written informed consent, structural magnetic resonance imaging data were prospectively acquired in 28 patients and 28 control subjects. OAB symptoms were assessed using the OAB symptom score (OABSS) scale. The gray matter volume (GMV) of each voxel was compared between the two groups while controlling for the effects of age, sex, and education level. Correlation analysis was performed to identify correlations between abnormal GMV regions and OABSS scores in patients. Multiple comparisons were corrected using a false discovery rate (FDR) method. Results: Patients with OAB exhibited a GMV reduction in the right cerebellum, bilateral hippocampus, left insula, right superior temporal gyrus, left anterior cingulate gyrus, bilateral caudate nucleus and right middle frontal gyrus. Furthermore, there was a significant negative correlation between the local GMV of the right cerebellar hemisphere and OABSS score. Conclusions: Patients with OAB have abnormal GMV in brain regions localized within the brain-bladder control network. It deepens our understanding of the structural changes in the brain area of the network. The patterns of structural reorganization in patients with OAB may provide useful information in the neuropathological mechanisms of the OAB. [ABSTRACT FROM AUTHOR]

With a growing interest in heritage languages from researchers of bilingualism and linguistic theory, the field of heritage-language studies has begun to build on its empirical foundations, moving toward a deeper understanding of the nature of language competence under unbalanced bilingualism. In furtherance of this trend, the current work synthesizes pertinent empirical observations and theoretical claims about vulnerable and robust areas of heritage language competence into early steps toward a model of heritage-language grammar. We highlight two key triggers for deviation from the relevant baseline: the quantity and quality of the input from which the heritage grammar is acquired, and the economy of online resources when operating in a less dominant language. In response to these triggers, we identify three outcomes of deviation in the heritage grammar: an avoidance of ambiguity, a resistance to irregularity, and a shrinking of structure. While we are still a ways away from a level of understanding that allows us to predict those aspects of heritage grammar that will be robust and those that will deviate from the relevant baselines, our hope is that the current work will spur the continued development of a predictive model of heritage language competence. [ABSTRACT FROM AUTHOR]

Structural reorganization is developed for preparing highly polymerized ultrathin g-C 3 N 4 nanosheets, which have a great potential in visible-light-driven CO 2 photoreduction. [Display omitted] • Highly polymerized ultrathin g-C 3 N 4 nanosheets are synthesized via structural reorganization. • The bridged N-(C) 3 provides more electron transfer channels with extended conjugate π → π* system as well as distorts the plane structure with activated n → π* electronic transition. • The prepared g-C 3 N 4 shows rapid and effective photoexcited carriers transfer and separation as well as extensional visible light absorption, resulting in highly active CO 2 photoreduction in a wide spectral range. • This work offers new design ideal for highly active g-C 3 N 4 materials in visible-light‐driven CO 2 photoreduction. Graphitic carbon nitride (g-C 3 N 4) exhibits moderate CO 2 photoreduction due to fast recombination of photoexcited charges and low-grade visible light absorption. Herein, we synthesized highly polymerized ultrathin g-C 3 N 4 nanosheets by structural reorganization. Both experimental and theoretical calculations indicate that amino groups stabilized by hydrogen bonding networks are the easiest to remove to form a more stable bridged N-(C) 3. This procedure provides additional electron transfer channels with an extended conjugated π → π* system and buckled plane structure with activated n → π* electronic transitions. This new configuration significantly improves the separation efficiency of photoexcited charges and widens the light absorption range. As a result, the prepared g-C 3 N 4 shows efficient CO 2 -to-CO conversion with a CO production rate of 12.95 μmol g-1 h−1 under λ ≥ 420 visible light and 2 μmol g-1 h−1 under λ ≥ 500 visible light, respectively. This work offers a new design idea for highly active visible-light-driven g-C 3 N 4 for CO 2 photoreduction. [ABSTRACT FROM AUTHOR]

Titanosilicates with large porosities are highly desirable for the selective liquid-phase epoxidation of alkenes in particular requiring open reaction spaces. Structural collapse and healing took place readily in one-pot when calcined and as-synthesized UTL-type germanosilicates both were subject to severe acid treatment, benefiting from the structural instability and modifiability of Ge-rich double four ring (D4R) units. Several structural derivatives with continuously tunable pore sizes were obtained by precisely controlling the acid treatment process. Isomorphous incorporation of Ti active centers and structural reorganization were then simultaneously realized via solid-liquid phase treatment using aqueous hexafluorotitanic acid (H 2 TiF 6 ) solution, giving rise to three titanosilicates of Ti-ECNU-14 (OKO), Ti-ECNU-15 and Ti-UTL with different pore sizes varying form medium pores (10-ring) to extra-large pores (14-ring). The obtained titanosilicates with high content of tertrahedrally coordinated Ti ions in framework performed unique catalytic performance in the epoxidation of cyclic alkenes using hydrogen peroxide or anhydrous tert -butyl hydroperoxide as an oxidant. [ABSTRACT FROM AUTHOR]

The involvement of glial cells in the regulation of physiological functions is being increasingly recognized, yet their role in plasticity of neural oscillators has remained largely elusive. An excellent model system to address the latter function is the pacemaker nucleus of the weakly electric fish, Apteronotus leptorhynchus. This brainstem oscillator drives the fish's electric organ discharge in a one-to-one fashion, with median frequencies of 880 Hz in males and 740 Hz in females. Morphometric analysis of the pacemaker nucleus has shown that astrocytes outnumber mature neurons seven-fold, and oscillator neurons even 200-fold. A similar dominance of astrocytes occurs among the adult-born cells that differentiate into glia and neurons. The astrocytes form a dense meshwork of cells interconnected by gap junctions. The degree of association of astrocytic fibers with the neural oscillator cells, and the gap-junction coupling between individual astrocytes, exhibit a sexual dimorphism, which parallels the sexual dimorphisms in the output frequency of the pacemaker nucleus, and ultimately in the electric organ discharge of the fish. It is hypothesized that the dynamics in astroglial structure mediate differences in the capacity to buffer potassium, which increases during the generation of action potentials. These differences, in turn, affect the excitability of the neural oscillator cells, and thus the output frequency of the pacemaker nucleus. Comparison of the pacemaker nucleus with other brain oscillators suggests that modulation of the output activity is one of the chief functions of the interaction of glia with the neural oscillator cells.

The article covers the problems of optimization of multidisciplinary hospital’s work in modern conditions. The example of the district clinic pres- ents activities for the organization of inpatient and outpatient specialized medical assistance which allow to improve its quality and effectiveness.

We report a new approach for the synthesis of heterohexa- and heterodecametalates via the use of non-aqueous, microwave-assisted reaction conditions. The two novel molybdovanadates have been isolated and characterized in the solid and solution states using single-crystal X-ray diffraction, FT-IR, UV/Vis, multinuclear NMR spectroscopy, and ESI-MS. The relative stabilities of the possible structural isomers were probed using dispersion-corrected DFT calculations for both polyoxometalate systems. [ABSTRACT FROM AUTHOR]

Structural reorganization in white matter (WM) after stroke is a potential contributor to substitute or to newly establish the functional field on the injured brain in nature. Diffusion tensor imaging (DTI) is an imaging modality that can be used to evaluate damage and recovery within the brain. This method of imaging allows for in vivo assessment of the restricted movements of water molecules in WM and provides a detailed look at structural connectivity in the brain. For longitudinal DTI studies after a stroke, the conventional region of interest method and voxel-based analysis are highly dependent on the user-hypothesis and parameter settings for implementation. In contrast, tract-based spatial statistics (TBSS) allows for reliable voxel-wise analysis via the projection of diffusion-derived parameters onto an alignment-invariant WM skeleton. In this study, spatiotemporal WM changes were examined with DTI-derived parameters (fractional anisotropy, FA; mean diffusivity, MD; axial diffusivity, DA; radial diffusivity, RD) using TBSS 2 h to 6 weeks after experimental focal ischemic stroke in rats ( N = 6). FA values remained unchanged 2-4 h after the stroke, followed by a continuous decrease in the ipsilesional hemisphere from 24 h to 2 weeks post-stroke and gradual recovery from the ipsilesional corpus callosum to the external capsule until 6 weeks post-stroke. In particular, the fibers in these areas were extended toward the striatum of the ischemic boundary region at 6 weeks on tractography. The alterations of the other parameters in the ipsilesional hemisphere showed patterns of a decrease at the early stage, a subsequent pseudo-normalization of MD and DA, a rapid reduction of RD, and a progressive increase in MD, DA and RD with a decreased extent in the injured area at later stages. The findings of this study may reflect the ongoing processes on tissue damage and spontaneous recovery after stroke. [ABSTRACT FROM AUTHOR]

Features and perspectives of the structural economic reorganization in Ukraine on the modern stage are developed, main conceptual approaches to structural changes in national economy are summarized. Typical trends and separate problematic issues in the implementation of structural policy of the state on the present stage are defined.

The article covers an integration project of Voronezh enterprise of space-racket branch in combination with concern creation with holding elements and distinguishing of independent departments (divisions). Like model object holding the suggestion can be utilized as an element of integration of the enterprise branch.

One of the most abundant, prevailing, and life-threatening human diseases that are currently baffling the scientific community is type 2 diabetes (T2D). The self-association of human amylin has been implicated in the pathogenesis of T2D, though with an inconclusive understanding of the mechanism. Hence, we focused on the characterization of the conformational ensembles of all the species that are believed to define the structural polymorphism of the aggregation process – the functional monomeric, the initially self-associated oligomeric, and the structured protofibril – by employing near-equilibrium, non-equilibrium, and equilibrium atomistic simulations on the sporadic, two familial variants (S20G and G33R), and their proline-substituted forms (S20P and G33P). The dynamic near-equilibrium assays hint toward – the abundance of helical conformation in the monomeric state, the retainment of the helicity in the initial self-associated oligomeric phase pointing toward the existence of the helix-helix association mechanism, the difference in preference of specific segments to have definite secondary structural features, the phase-dependent variability in the dominance of specific segments and mutation sites, and the simultaneous presence of generic and unique features among various sequences. Furthermore, the non-equilibrium pulling assays exemplify a generic sequential unzipping mechanism of the protofibrils, however, the sequence-dependent uniqueness comes from the difference in location and magnitude of the control of a specific terminus. Importantly, the equilibrium thermodynamic assays efficiently rank order the potential of aggregability among sequences and consequently suggests the probability of designing effective aggregation suppressors against sporadic and familial amylin variants incorporating proline as the mutation. [Display omitted] • Heterogeneous helix-dominant monomeric conformational ensembles. • Helix-helix association leads to the genesis of the initial oligomeric conformations. • Position-specific secondary structure tendency dictates aggregation pathway. • Relative rank-ordering of sporadic and familial causes of T2D. • Single-point mutation to Proline acts as a generic aggregation suppressor. [ABSTRACT FROM AUTHOR]

The current dogma to explain the extent of injury-related changes following rodent controlled cortical impact (CCI) injury is a focal injury with limited axonal pathology. However, there is in fact good, published histologic evidence to suggest that axonal injury is far more widespread in this model than generally thought. One possibility that might help to explain this is the often-used region-of-interest data analysis approach taken by experimental traumatic brain injury (TBI) diffusion tensor imaging (DTI) or histologic studies that might miss more widespread damage, when compared to the whole brain, statistically robust method of tract-based analysis used more routinely in clinical research. To determine the extent of DTI changes in this model, we acquired in vivo DTI data before and at 1 and 4 weeks after CCI injury in 17 adult male rats and analyzed parametric maps of fractional anisotropy (FA), axial, radial, and mean diffusivity (AD, RD, MD), tensor mode (MO), and fiber tract density (FTD) using tract-based spatial statistics. Contusion volume was used as a surrogate marker of injury severity and as a covariate for investigating severity dependence of the data. Mean fiber tract length was also computed from seeds in the cortical spinal tract regions. In parallel experiments ( n = 3–5/group), we investigated corpus callosum neurofilaments and demyelination using immunohistochemistry (IHC) at 3 days and 6 weeks, callosal tract patency using dual-label retrograde tract tracing at 5 weeks, and the contribution of gliosis to DTI parameter maps using GFAP IHC at 4 weeks post-injury. The data show widespread ipsilateral regions of significantly reduced FA at 1 week post-injury, driven by temporally changing values of AD, RD, and MD that persist to 4 weeks. Demyelination, retrograde label tract loss, and reductions in MO (tract degeneration) and FTD were shown to underpin these data. Significant FA increases occurred in subcortical and corticospinal tract regions that were spatially distinct from regions of FA decrease, grossly affected gliotic areas, and MO changes. However, there was good spatial correspondence between regions of increased FA and areas of increased FTD and mean fiber length. We discuss these widespread changes in DTI parameters in terms of axonal degeneration and potential reorganization, with reference to a resting state fMRI companion paper (Harris et al., 2016, Exp. Neurol. 227:124–138) that demonstrated altered functional connectivity data acquired from the same rats used in this study. [ABSTRACT FROM AUTHOR]

Shape-selective stannosilicates have been post-synthesized for the hydration of epoxide to diols. A simple acid treatment has been employed to remove extensively the interlayer double four ring units, converting the three-dimensional (3D) UTL germanosilicate into a 2D layered IPC-1P intermediate. Isomorphous incorporation of tetrahedrally coordinated Sn active centers was realized via solid-liquid treatment of IPC-1P with diammonium hexachlorostannate aqueous solution, which was accompanied by the spontaneous condensation of neighboring silica-rich cfi layers upon calcination and structural construction of a 3D PCR structure. Sn-PCR stannosilicates with tunable Sn contents were thus prepared. With Sn-derived robust Lewis acidity confined in the intersecting 10- and 8-ring channels, the Sn-PCR (Si/Sn molar ratio of 77) catalyst served as a shape-selective nanoreactor for the hydration of ethylene oxide (EO) into ethylene glycol (EG), exhibiting a remarkable EO conversion (99.5 %) as well as a steady EG selectivity (>98.4 %) at greatly reduced H 2 O/EO molar ratio and near-ambient reaction temperature., (© 2022 Wiley-VCH GmbH.)

The binding thermodynamics and interaction of the putative anticancer alkaloid chelerythrine with polyadenylic acid were investigated by isothermal titration calorimetry, absorption and fluorescence spectroscopy, circular dichroism, differential scanning calorimetry and thermal melting experiments. The equilibrium binding constant was evaluated to be of the order of 10 7 M −1 . Strong positive entropic and favorable enthalpic contributions to the binding were revealed. The binding affinity was enhanced within (10 to 100) mM Na + concentration. Circular dichroism spectra confirmed that the increase in entropy change was caused by a strong conformational change in the RNA polynucleotide. Absorption and circular dichroism melting studies revealed that chelerythrine binding induced self-assembled duplex structure formation in poly(A) molecules resulting in a cooperative melting profile. This was further confirmed from differential scanning calorimetry data. The intercalation binding of the alkaloid involved strong energy transfer from the polynucleotide bases to the bound alkaloid molecules. The remarkably high entropy driven binding of the alkaloid induced spontaneous self-assembled structure formation in poly(A) and the associated binding affinity is the highest so far reported for a small molecule binding to poly(A). [ABSTRACT FROM AUTHOR]

Histomorphometric and immunohistochemical analyses showed season-dependent changes in the morphofunctional parameters of the structural components of the thyroid gland in males of indigenous (Yakuts, Evens, and Evenkis) and non-indigenous (Russian and Ukrainians) populations of the Republic of Sakha (Yakutia) in different seasons. External and internal diameters of follicles and area of the colloid in the thyroid gland was higher in non-indigenous than in non-indigenous individuals both in summer and in winter. The height of thyroid epithelium, areas of thyrocytes and their nuclei, and nucleocytoplasmic index of the thyroid gland were lower in men from non-indigenous population in summer, and higher in winter than in non-indigenous inhabitants. Transition of a part of follicular apparatus of the thyroid gland to enhanced activity during winter was less pronounced in indigenous males in comparison with non-indigenous subjects. [ABSTRACT FROM AUTHOR]

Abstract: Reference kaolins KGa-1b, KGa-2 and KF are used as starting materials to examine the effect of chemically added iron on their structural transformations (near 950–980°C) during sintering. The equivalent total Fe2O3 content is varied from 0.21 to 11.72 mass%. Iron addition leads to strong modification of the structural reorganization path of metakaolinite. Iron ions start to diffuse into metakaolinite network at 900°C and lead to an early breakdown of the system. The corresponding exothermic peak is shifted from 970°C to 900°C. Regarding the heating rate, this peak appears to result from three overlapping reactions. The peak temperatures of these reactions are respectively 925°C, 950°C and 970°C. A low heating rate enhances iron diffusion, promoting the structural reorganization process. [Copyright &y& Elsevier]

Abstract: The human brain''s ability to adapt to environmental changes is obvious in specific sensory domains of experts, and olfaction is one of the least investigated senses. As we have previously demonstrated that olfactory expertise is related to functional brain modifications, we investigated here whether olfactory expertise is also coupled with structural changes. We used voxel-based morphometry to compare the gray-matter volume in student and professional perfumers, as well as untrained control subjects, and accounted for all methodological improvements that have been recently developed to limit possible errors associated with image processing. In all perfumers, we detected an increase in gray-matter volume in the bilateral gyrus rectus/medial orbital gyrus (GR/MOG), an orbitofrontal area that surrounds the olfactory sulcus. In addition, gray-matter volume in the anterior PC and left GR/MOG was positively correlated with experience in professional perfumers. We concluded that the acute olfactory knowledge acquired through extensive olfactory training leads to the structural reorganization of olfactory brain areas. [Copyright &y& Elsevier]

Abstract: Objective: To investigate structural reorganization in the brain with differential visual experience using Voxel-Based Morphometry with Diffeomorphic Anatomic Registration Through Exponentiated Lie algebra algorithm (DARTEL) approach. Materials and methods: High resolution structural MR images were taken in fifteen normal sighted healthy controls, thirteen totally blind subjects and six partial blind subjects. The analysis was carried out using SPM8 software on MATLAB 7.6.0 platform. Results: VBM study revealed gray matter volume atrophy in the cerebellum and left inferior parietal cortex in total blind subjects and in left inferior parietal cortex, right caudate nucleus, and left primary visual cortex in partial blind subjects as compared to controls. White matter volume loss was found in calcarine gyrus in total blind subjects and Thlamus-somatosensory region in partially blind subjects as compared to controls. Besides, an increase in Gray Matter volume was also found in left middle occipital and middle frontal gyrus and right entorhinal cortex, and an increase in White Matter volume was found in superior frontal gyrus, left middle temporal gyrus and right Heschl''s gyrus in totally blind subjects as compared to controls. Comparison between total and partial blind subjects revealed a greater Gray Matter volume in left cerebellum of partial blinds and left Brodmann area 18 of total blind subjects. Conclusion: Results suggest that, loss of vision at an early age can induce significant structural reorganization on account of the loss of visual input. These plastic changes are different in early onset of total blindness as compared to partial blindness. [Copyright &y& Elsevier]

In 1989–2005 the qualitative composition and seasonal and inter-annual dynamics of the total biomass of phytoplankton, chlorophyll a content, hydrological, and hydrochemical parameters were studied in the Russian zone of the Vistula Lagoon in the Baltic Sea. The results of these observations were compared to the data obtained in the 1950s and 1970s. The structural reorganization of phytoplankton was revealed, testifying to the negative changes in the ecosystem under conditions of anthropogenic pollution and eutrophication, climate warming, and increasing salinity. [ABSTRACT FROM AUTHOR]

Abstract: The novel coordination polymer {[Co(Hbtc)(4-bpmp)(H2O)]·3H2O} (1, btc=1,3,5-benzenetricarboxylate, 4-bpmp= N,N′-bis(4-pyridylmethyl)piperazine) has been prepared by hydrothermal synthesis and characterized by single crystal X-ray diffraction, IR and thermogravimetric analysis. Individual [Co(Hbtc)(4-bpmp)(H2O)] n layers mutually interpenetrate in a 2d+2d→3D inclined fashion to produce channels coursing down the c crystal direction, occupied by “infinite” 1D water molecule chains. Dehydration of 1 results in structural reorganization to a monoclinic phase, which is converted to an amorphous phase upon rehydration. [Copyright &y& Elsevier]

Abstract: Theoretical calculations were performed to study the nature of the N–H⋯H–B blue-shifted dihydrogen bond in the complex BH3NH3⋯HNO. The geometric structures and vibrational frequencies of the complex BH3NH3⋯HNO at the MP2/6-31+G(d,p), MP2/6-311++G(d,p), B3LYP/6-31+G(d,p) and B3LYP/6-311++G(d,p) levels are calculated by standard and counterpoise-corrected methods, respectively. In the N–H⋯H–B dihydrogen bond, the calculated blue shift of N–H stretching frequency is in the vicinity of 130cm−1. From the natural bond orbital analysis it can be seen that the N–H bond length in the N–H⋯H–B dihydrogen bond is controlled by a balance of four main factors in the opposite directions: hyperconjugation, electron density redistribution, rehybridization and structural reorganization. Among them hyperconjugation has the effect of elongating the X–H bond, and the other three factors belong to the bond shortening effects. In the N–H⋯H–B dihydrogen bond, the shortening effects dominate which lead to the blue shift of the N–H stretching frequencies. In addition, solvent effect on the geometric structures, vibrational frequencies and interaction energies of the monomer and complex was studied in detail. It is relevant to the relatively dielectric constants (ε). [Copyright &y& Elsevier]

The X-ray crystal structure of the reaction product of acetylcholinesterase (AChE) with the inhibitor diisopropylphosphorofluoridate (DFP) showed significant structural displacement in a loop segment of residues 287–290. To understand this conformational selection, a Monte Carlo (MC) simulation study was performed of the energy landscape for the loop segment. A computational strategy was applied by using a combined simulated annealing and room temperature Metropolis sampling approach with solvent polarization modeled by a generalized Born (GB) approximation. Results from thermal annealing reveal a landscape topology of broader basin opening and greater distribution of energies for the displaced loop conformation, while the ensemble average of conformations at 298 K favored a shift in populations toward the native by a free-energy difference in good agreement with the estimated experimental value. Residue motions along a reaction profile of loop conformational reorganization are proposed where Arg-289 is critical in determining electrostatic effects of solvent interaction versus Coulombic charging. [Copyright &y& Elsevier]

The influence of calcination and redox cycles on the structural modification and redox properties of a ceria–zirconia mixed oxide of nominal composition Ce0.6Zr0.4O2 were investigated by XRD and Rietveld refinement, by BET measurement, TPR and OSC analyses. The material is characterized by high total OSC and retains this property after several redox and calcination cycles up to 1273 K, despite the loss of porosity and the decrease of surface area. The Rietveld analysis of the diffractograms allowed to establish that at least two solid solutions are present in the as-prepared sample: a cubic phase, space group Fm-3m, richer in cerium compared to the nominal composition, a tetragonal phase (t′) richer in zirconium. The first redox treatment modifies the composition towards two different solid solutions with composition closer to the nominal one: a cubic Ce0.65Zr0.35O2 and a tetragonal (t′) Ce0.47Zr0.53O2. No changes are noticed after four further redox cycles, while the successive calcination at 1273 K gives rise to a second cubic phase richer in cerium and to another tetragonal phase richer in zirconium. Noteworthy a further redox cycle reorganizes the sample to a similar situation as before the calcination treatment and this configuration is maintained for four redox cycles. This alternance is restored after calcination and successive four redox cycles. The total OSC measured after the above treatments is high and increases after the successive cycles. [Copyright &y& Elsevier]

Ceria-zirconia mixed oxides of nominal composition Ce0.6Zr0.4O2 were prepared by sol-gel method. The structural and morphological modifications of these materials due to calcination and redox treatments up to 1000°C were studied by X-ray diffraction (XRD) and Rietveld refinements, specific surface area measurements (BET), oxygen storage capacity (OSC), TEM and SEM analyses. The materials maintain high OSC after several hours of treatments at 1000°C in oxidizing and reducing atmosphere, showing good resistance to the thermal ageing. An improvement of the OSC is manifested after repetitive redox cycles, even though textural characterization shows that reduction/oxidation processes induce sintering of the crystallites. [ABSTRACT FROM AUTHOR]

Metal-phenolic networks (MPNs) are amorphous materials that can be used to engineer functional films and particles. A fundamental understanding of the heat-driven structural reorganization of MPNs can offer opportunities to rationally tune their properties ( e . g ., size, permeability, wettability, hydrophobicity) for applications such as drug delivery, sensing, and tissue engineering. Herein, we use a combination of single-molecule localization microscopy, theoretical electronic structure calculations, and all-atom molecular dynamics simulations to demonstrate that MPN plasticity is governed by both the inherent flexibility of the metal (Fe III )-phenolic coordination center and the conformational elasticity of the phenolic building blocks (tannic acid, TA) that make up the metal-organic coordination complex. Thermal treatment (heating to 150 °C) of the flexible TA/Fe III networks induces a considerable increase in the number of aromatic π-π interactions formed among TA moieties and leads to the formation of hydrophobic domains. In the case of MPN capsules, 15 min of heating induces structural rearrangements that cause the capsules to shrink (from ∼4 to ∼3 μm), resulting in a thicker (3-fold), less porous, and higher protein ( e.g. , bovine serum albumin) affinity MPN shell. In contrast, when a simple polyphenol such as gallic acid is complexed with Fe III to form MPNs, rigid materials that are insensitive to temperature changes are obtained, and negligible structural rearrangement is observed upon heating. These findings are expected to facilitate the rational engineering of versatile TA-based MPN materials with tunable physiochemical properties for diverse applications.

The corpus callosum is the largest white matter pathway in the brain connecting the two hemispheres. In the context of developmental absence (agenesis) of the corpus callosum (AgCC), a proposed candidate for neuroplastic response is strengthening of intrahemispheric pathways. To test this hypothesis, we assessed structural and functional connectivity in a uniquely large cohort of children with AgCC (n = 20) compared with typically developing controls (TDC, n = 29), and then examined associations with neurobehavioral outcomes using a multivariate data-driven approach (partial least squares correlation, PLSC). For structural connectivity, children with AgCC showed a significant increase in intrahemispheric connectivity in addition to a significant decrease in interhemispheric connectivity compared with TDC, in line with the aforementioned hypothesis. In contrast, for functional connectivity, children with AgCC and TDC showed a similar pattern of intrahemispheric and interhemispheric connectivity. In conclusion, we observed structural strengthening of intrahemispheric pathways in children born without corpus callosum, which seems to allow for functional connectivity comparable to a typically developing brain, and were relevant to explain neurobehavioral outcomes in this population. This neuroplasticity might be relevant to other disorders of axonal guidance, and developmental disorders in which corpus callosum alteration is observed., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)

Glucokinase (GK) plays a key role in the regulation of hepatic glucose metabolism. An unusual mechanism of positive cooperativity of monomeric GK containing only a single binding site for glucose is very interesting and still unclear. The activation process of GK is associated with a large-scale conformational change from the inactive to the active state. Here, conventional and targeted molecular dynamics simulations were used to study the conformational dynamics of GK in the stable configurations and in the transition from active to inactive state. Three phases of the structural reorganization of GK were detected. The first step is a transformation of GK from the active state to the intermediate structure, where the cleft between the domains is open, but alpha helix 13 is still inside the small domain. From this point, there are two alternative paths. One path leads to the inactive state through the release of helix 13 from the inside of small domain to the outside. Other path goes back to the active state. Simulation results reveal the critical role of helix 13 in the transformation of GK from the open state to inactive one and the influence of the loop 2 on the protein transformation between the open and the closed active states. Principal component analysis and covariance matrix analysis were carried out to analyze the dynamics of protein. Importance of hydrogen bonds in the stability of the closed conformation is shown. Overall, our simulations provide new information about the dynamics of GK and its structural transformation.Communicated by Ramaswamy H. Sarma.

In recent years, with the growing demand for higher capacity, longer cycling life, and higher power and energy density of lithium ion batteries (LIBs), the traditional insertion-based anodes are increasingly considered out of their depth. Herein, attention is paid to the structural reorganization electrode, which is the general term for conversion-based and alloying-based materials according to their common characteristics during the lithiation/delithiation process. This Review summarizes the recent achievements in improving and understanding the lithium storage performance of conversion-based anodes (especially the most widely studied transition metal oxides like Mn-, Fe-, Co-, Ni-, and Cu-based oxides) and alloying-based anodes (mainly including Si-, Sn-, Ge-, and Sb-based materials). The synthesis schemes, morphological control and reaction mechanism of these materials are also included. Finally, viewpoints about the challenges and feasible improvement measures for future development in this direction are given. The aim of this Review is to shed some light on future electrode design trends of structural reorganization anode materials for LIBs., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)