Zero-Dimensional Sn-Based Enantiomeric Phase-Transition Materials with High-Tc and Dielectric Switching.

The combination of chirality and phase-transition materials has broad application prospects. Therefore, based on the quasi-spherical theory and the thought strategy of introducing chirality, we have successfully synthesized a pair of chiral enantiomeric ligands (R/S)-triethyl-(2-hydroxypropyl)ammonium iodide, which can be combined with a tin hexachloride anion to obtain a pair of new organic-inorganic hybrid enantiomeric high-temperature plastic phase-transition materials: (R/S)-[CH3 CH(OH)CH2 N(CH2 CH3 )3 ]2 SnCl6 (1-R/1-S), which have a high temperature phase transition of Tc =384 K, crystallize in the P21 chiral space group at room temperature, and have obvious CD signals. In addition, compounds 1-R and 1-S have a good low-loss dielectric switch and broadband gap. This work is conducive to the research into chiral high-temperature reversible plastic phase-transition materials, and promotes the development of multi-functional phase-transition materials.

LSD1 inhibitors from the roots of Pueraria lobata.

One new 6a,11a-dehydropterocarpan derivative, 6-O-methyl-anhydrotuberosin (1), one new 6a-hydroxypterocarpan, (6aR,11aR,11bR)-hydroxytuberosone (7), and seven known compounds including two 6a,11a-dehydropterocarpans (2 and 4), two coumestans (3 and 5), one isoflavonoid (6) and two other phenolic compounds (8 and 9) were isolated from the roots of Pueraria lobata. The structures of the isolated compounds were elucidated with spectroscopic and spectrometric methods (1 D and 2DNMR, HRESIMS). Compounds 1, 2, 4-5 showed potent LSD1 inhibitory activities with IC50 values ranging from 1.73 to 4.99 µM. Furthermore, compound 2 showed potent cytotoxicity against gastric cancer cell lines MGC-803 and BGC-823, and lung cancer cell lines H1299 and H460.

1,10-seco guaianolide-type sesquiterpenoids from Chrysanthemum indicum.

ABSTACTA chemical investigation of the whole plant of traditional Chinese medicine, Chrysanthemum indicum L., led to the discovery of six guaianolide-type sesquiterpenoids 1-6 with a 1,10-splited skeleton. The structure of the new compound 1 was established by extensive analysis of UV, IR, MS, NMR and ECD data. Compounds 3-6 are mutually stereoisomers with four chiral centers and their absolute configurations were determined by comparison of ECD spectra. The anti-inflammatory effects of these isolates on lipopolysaccharide (LPS)-induced nitric oxide (NO) were investigated in RAW 264.7 cells. Results showed that most of the compounds displayed NO production inhibitory activities with IC50 values ranged from 3.54 to 8.17 µM.

Architecture and coevolution of allosteric materials.

We introduce a numerical scheme to evolve functional elastic materials that can accomplish a specified mechanical task. In this scheme, the number of solutions, their spatial architectures, and the correlations among them can be computed. As an example, we consider an "allosteric" task, which requires the material to respond specifically to a stimulus at a distant active site. We find that functioning materials evolve a less-constrained trumpet-shaped region connecting the stimulus and active sites, and that the amplitude of the elastic response varies nonmonotonically along the trumpet. As previously shown for some proteins, we find that correlations appearing during evolution alone are sufficient to identify key aspects of this design. Finally, we show that the success of this architecture stems from the emergence of soft edge modes recently found to appear near the surface of marginally connected materials. Overall, our in silico evolution experiment offers a window to study the relationship between structure, function, and correlations emerging during evolution.

Mechanics of Allostery: Contrasting the Induced Fit and Population Shift Scenarios.

In allosteric proteins, binding a ligand can affect function at a distant location, for example, by changing the binding affinity of a substrate at the active site. The induced fit and population shift models, which differ by the assumed number of stable configurations, explain such cooperative binding from a thermodynamic viewpoint. Yet, understanding what mechanical principles constrain these models remains a challenge. Here, we provide an empirical study on 34 proteins supporting the idea that allosteric conformational change generally occurs along a soft elastic mode presenting extended regions of high shear. We argue, based on a detailed analysis of how the energy profile along such a mode depends on binding, that in the induced fit scenario, there is an optimal stiffness ka∗ ∼ 1/N for cooperative binding, where N is the number of residues. We find that the population shift scenario is more robust to mutations affecting stiffness because binding becomes more and more cooperative with stiffness up to the same characteristic value ka∗, beyond which cooperativity saturates instead of decaying. We numerically confirm these findings in a nonlinear mechanical model. Dynamical considerations suggest that a stiffness of order ka∗ is favorable in that scenario as well, supporting that for proper function, proteins must evolve a functional elastic mode that is softer as their size increases. In consistency with this view, we find a fair anticorrelation between the stiffness of the allosteric response and protein size in our data set.

MiR-330-3p suppresses phosphoglycerate mutase family member 5 -inducted mitophagy to alleviate hepatic ischemia-reperfusion injury.

Mitochondrial dysfunction plays a central role in hepatic ischemia-reperfusion injury (IRI). The significance of mitophagy in hepatic IRI remains poorly understood. The mechanisms that cause IRI are complex, and many factors are involved in the injury formation process. The miR-330-3p mediates cell proliferation, cell death, and metabolism in various organisms. In this study, the levels of miR-330-3p were significantly downregulated in hepatic IRI, and the number of autophagosomes was increased in response to IRI as obtained under both in vivo and in vitro conditions. These results demonstrate that a reduction in miR-330-3p expression represents an important factor involved with promoting hepatic IRI. Moreover, we found that miR-330-3p interacted with phosphoglycerate mutase family member 5 (PGAM5) to regulate mitophagy. In specific, an overexpression of miR-330-3p diminished PGAM5 levels, which promoted mitophagy in response to IRI. In contrast, a downregulation of miR-330-3p was associated with increased PGAM5 levels leading to increased mitophagy. In conclusion, miR-330-3p suppresses PGAM5-induced mitophagy to alleviate hepatic IRI. Such findings not only reveal some of the mechanistic basis for this microRNA in liver injury, but also provide a foundation for new therapeutic approaches in the treatment of this condition.

Scale-free channeling patterns near the onset of erosion of sheared granular beds.

Erosion shapes our landscape and occurs when a sufficient shear stress is exerted by a fluid on a sedimented layer. What controls erosion at a microscopic level remains debated, especially near the threshold forcing where it stops. Here we study, experimentally, the collective dynamics of the moving particles, using a setup where the system spontaneously evolves toward the erosion onset. We find that the spatial organization of the erosion flux is heterogeneous in space and occurs along channels of local flux σ whose distribution displays scaling near threshold and follows [Formula: see text], where J is the mean erosion flux. Channels are strongly correlated in the direction of forcing but not in the transverse direction. We show that these results quantitatively agree with a model where the dynamics is governed by the competition of disorder (which channels mobile particles) and particle interactions (which reduces channeling). These observations support that, for laminar flows, erosion is a dynamical phase transition that shares similarity with the plastic depinning transition occurring in dirty superconductors. The methodology we introduce here could be applied to probe these systems as well.

Principles for Optimal Cooperativity in Allosteric Materials.

Allosteric proteins transmit a mechanical signal induced by binding a ligand. However, understanding the nature of the information transmitted and the architectures optimizing such transmission remains a challenge. Here we show, using an in silico evolution scheme and theoretical arguments, that architectures optimized to be cooperative, which efficiently propagate energy, qualitatively differ from previously investigated materials optimized to propagate strain. Although we observe a large diversity of functioning cooperative architectures (including shear, hinge, and twist designs), they all obey the same principle of displaying a mechanism, i.e., an extended soft mode. We show that its optimal frequency decreases with the spatial extension L of the system as L-d/2, where d is the spatial dimension. For these optimal designs, cooperativity decays logarithmically with L for d = 2 and does not decay for d = 3. Overall, our approach leads to a natural explanation for several observations in allosteric proteins and indicates an experimental path to test if allosteric proteins lie close to optimality.

Predicting Parametrial Invasion in Cervical Carcinoma (Stages IB1, IB2, and IIA): Diagnostic Accuracy of T2-Weighted Imaging Combined With DWI at 3 T.

OBJECTIVE: The objective of our study was to retrospectively evaluate the efficacy of combined analysis of T2-weighted imaging and DWI in the diagnosis of parametrial invasion (PMI) in cervical carcinoma. MATERIALS AND METHODS: The clinical records of 192 patients with cervical carcinoma who met the study requirements were reviewed for this retrospective study. The signal intensities of suspicious PMI tissue were assessed on T2-weighted images, DW images, and apparent diffusion coefficient maps independently by two experienced radiologists. The radiologist observers predicted the presence of PMI by scoring T2-weighted imaging alone and then by scoring T2-weighted imaging and DWI combined. The results were compared with histopathologic findings. RESULTS: Histopathologic findings revealed PMI in 24 of 192 study subjects. In positively predicting the presence of PMI, T2-weighted imaging and DWI combined scored significantly better than T2-weighted imaging alone, as proven by high sensitivity (T2-weighted imaging alone vs T2-weighted imaging and DWI combined: observer 1, 75.0% vs 83.3% [p = 0.477]; observer 2, 66.7% vs 91.7% [p < 0.05]), high specificity (T2-weighted imaging alone vs T2-weighted imaging and DWI combined: observer 1, 84.5% vs 98.8% [p < 0.001]; observer 2, 85.7% vs 98.8% [p < 0.001]), and high accuracy (T2-weighted imaging alone vs T2-weighted imaging and DWI combined: observer 1, 83.3% vs 96.9% [p < 0.001]; observer 2, 83.3% vs 97.9% [p < 0.001]). The area under the ROC curve was also significantly higher for T2-weighted imaging and DWI combined (observer 1, 0.911; observer 2, 0.952) than for T2-weighted imaging alone (observer 1, 0.798; observer 2, 0.762). Although the interobserver agreement was good for T2-weighted imaging (κ = 0.695) and excellent for T2-weighted imaging and DWI combined (κ = 0.753), the improvement failed to achieve statistical significance (p = 0.28). CONCLUSION: Combined analysis of T2-weighted imaging and DWI enhances the accuracy of diagnosing PMI in patients with cervical cancer compared with T2-weighted imaging alone.

[Intestinal absorption properties of ponicidin by single pass perfusion model in rats].

To determine the absorption properties and study the intestinal absorption kinetics of poncidin in rats. In situ single pass perfusion model was combined with High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS/MS) method to investigate the intestinal absorption characteristics and calculate absorption parameters with aspects of drug absorption, concentration and perfusion medium. The absorption of poncidin under acid condition at pH 6.5 was more stable, where intestinal enzymes showed little influence on metabolism, and the absorption was significantly higher than that in pH alkaline condition at pH 8.0 (P<0.05). Drug concentrations had no significant influence on absorption rate constant of the same intestinal segment Ka and apparent permeability coefficient Papp values of poncidin. Different concentrations of poncidin showed no significant differences in the Ka and Papp values among duodenum, jejunum and colon, but the values were significantly lower than ileum absorption parameters, with significant differences (P<0.05). There was no significant effect of verapamil on intestinal absorption of poncidin. The results showed that poncidin could be absorbed at all the studied intestinal segments while ileum seemed to be the best absorption segment in the concentration range of 10-1 000 µg·L⁻¹. The absorption was characterized by a linear dynamic process of passive transport, without absorption saturation. Weak acid environment was helpful for the intestinal absorption of poncidin, and ponicidin was not a substrate of P-glycoprotein (P-gp).

Edge mode amplification in disordered elastic networks.

Understanding how mechanical systems can be designed to efficiently transport elastic information is important in a variety of fields, including in materials science and biology. Recently, it has been discovered that certain crystalline lattices present "topologically-protected" edge modes that can amplify elastic signals. Several observations suggest that edge modes are important in disordered systems as well, an effect not well understood presently. Here we build a theory of edge modes in disordered isostatic materials and compute the distribution g(κ) of Lyapunov exponents κ characterizing how modes penetrate in the bulk, and find good agreement with numerical results. We show that disordered isostatic materials generically act as levers with amplification of an order LL where L is the system size, whereas more connected materials amplify signals only close to free surfaces. Our approach, which is based on recent results in "free" random matrix theory, makes an analogy with electronic transport in a disordered conductor.

[Interaction and mechanism between poinicidin and BSA].

To establish a sensitive and specific LC-MS/MS method for determination of the binding conditions of ponicidin with bovine serum albumin (BSA) and analysis of its mechanism. The protein binding rates and related binding constants of ponicidin in BSA samples were determined by ultrafiltration and LC-MS/MS. Scatchard equation was used to calculate the binding constant (Ka) of ponicidin in BSA samples as well as the number of binding sites (n), and the mechanism on ponicidin binding with BSA was explored. The results showed that the average protein binding rate of ponicidin with BSA was 57.2%, mainly as grade Ⅰ intensive binding, and the relevant binding constant was 2.54×104 L•µg⁻¹, with a binding site number of n=0.75. The binding of ponicidin with BSA had no concentration dependence within the investigated concentrations. The established method in this study showed high sensitivity, specificity, simple operation and met the analysis requirements, and the calculation of binding constant laid foundation for the clinical drug interactions and pharmacokinetics research.

Role of thymosin beta 4 in hair growth.

Although thymosin beta 4 (Tß4) is known to play a role in hair growth, its mechanism of action is unclear. We examined the levels of key genes in a Tß4 epidermal-specific over-expressing mouse model and Tß4 global knockout mouse model to explore how Tß4 affects hair growth. By depilation and histological examination of the skin, we confirmed the effect of Tß4 on hair growth, the number of hair shafts and hair follicle (HF) structure. The mRNA and protein expression of several genes involved in hair growth were detected by real-time PCR and western blotting, respectively. Changes in the expression of ß-catenin and Lef-1, the two key molecules in the Wnt signaling pathway, were similar to the changes observed in Tß4 expression. We also found that compared to the control mice, the mRNA and protein expression of MMP-2 and VEGF were increased in the Tß4 over-expressing mice, while the level of E-cadherin (E-cad) remained the same. Further, in the Tß4 global knockout mice, the mRNA and protein levels of MMP-2 and VEGF decreased dramatically and the level of E-cad was stable. Based on the above results, we believe that Tß4 may regulate the levels of VEGF and MMP-2 via the Wnt/ß-catenin/Lef-1 signaling pathway to influence the growth of blood vessels around HFs and to activate cell migration. Tß4 may have potential for the treatment of hair growth problems in adults, and its effects should be further confirmed in future studies.

Why glass elasticity affects the thermodynamics and fragility of supercooled liquids.

Supercooled liquids are characterized by their fragility: The slowing down of the dynamics under cooling is more sudden and the jump of specific heat at the glass transition is generally larger in fragile liquids than in strong ones. Despite the importance of this quantity in classifying liquids, explaining what aspects of the microscopic structure controls fragility remains a challenge. Surprisingly, experiments indicate that the linear elasticity of the glass--a purely local property of the free energy landscape--is a good predictor of fragility. In particular, materials presenting a large excess of soft elastic modes, the so-called boson peak, are strong. This is also the case for network liquids near the rigidity percolation, known to affect elasticity. Here we introduce a model of the glass transition based on the assumption that particles can organize locally into distinct configurations that are coupled spatially via elasticity. The model captures the mentioned observations connecting elasticity and fragility. We find that materials presenting an abundance of soft elastic modes have little elastic frustration: Energy is insensitive to most directions in phase space, leading to a small jump of specific heat. In this framework strong liquids turn out to lie the closest to a critical point associated with a rigidity or jamming transition, and their thermodynamic properties are related to the problem of number partitioning and to Hopfield nets in the limit of small memory.

Edaravone attenuates brain damage in rats after acute CO poisoning through inhibiting apoptosis and oxidative stress.

Acute carbon monoxide (CO) poisoning is the most common cause of death from poisoning all over the world and may result in neuropathologic and neurophysiologic changes. Acute brain damage and delayed encephalopathy are the most serious complication, yet their pathogenesis is poorly understood. The present study aimed to evaluate the neuroprotective effects of Edaravone against apoptosis and oxidative stress after acute CO poisoning. The rat model of CO poisoning was established in a hyperbaric oxygen chamber by exposed to CO. Ultrastructure changes were observed by transmission electron microscopy (TEM). TUNEL stain was used to assess apoptosis. Immunohistochemistry and immunofluorescence double stain were used to evaluate the expression levels of heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf-2) protein and their relationship. By dynamically monitored the carboxyhemoglobin (HbCO) level in blood, we successfully established rat model of severe CO poisoning. Ultrastructure changes, including chromatin condensation, cytoplasm dissolution, vacuoles formation, nucleus membrane and cell organelles decomposition, could be observed after CO poisoning. Edaravone could improve the ultrastructure damage. CO poisoning could induce apoptosis. Apoptotic cells were widely distributed in cortex, striatum and hippocampus. Edaravone treatment attenuated neuronal apoptosis as compared with the poisoning group (P < 0.01). Basal expressions of HO-1 and Nrf-2 proteins were found in normal brain tissue. CO poisoning could activate HO-1/Nrf-2 pathway, start oxidative stress response. After the administration of Edaravone, the expression of HO-1 and Nrf-2 significantly increased (P < 0.01). These findings suggest that Edaravone may inhibit apoptosis, activate the Keapl-Nrf/ARE pathway, and thus improve the ultrastructure damage and neurophysiologic changes following acute CO poisoning.

Dynamics and Correlations among Soft Excitations in Marginally Stable Glasses.

Marginal stability is the notion that stability is achieved, but only barely so. This property constrains the ensemble of configurations explored at low temperature in a variety of systems, including spin, electron, and structural glasses. A key feature of marginal states is a (saturated) pseudogap in the distribution of soft excitations. We examine how such pseudogaps appear dynamically by studying the Sherrington-Kirkpatrick (SK) spin glass. After revisiting and correcting the multi-spin-flip criterion for local stability, we show that stationarity along the hysteresis loop requires soft spins to be frustrated among each other, with a correlation diverging as C(λ)∼1/λ, where λ is the stability of the more stable spin. We explain how this arises spontaneously in a marginal system and develop an analogy between the spin dynamics in the SK model and random walks in two dimensions. We discuss analogous frustrations among soft excitations in short range glasses and how to detect them experimentally. We also show how these findings apply to hard sphere packings.

Protective effect of a novel Rho kinase inhibitor WAR-5 in experimental autoimmune encephalomyelitis by modulating inflammatory response and neurotrophic factors.

The Rho-kinase (ROCK) inhibitor Fasudil has proven beneficial in experimental autoimmune encephalomyelitis (EAE). Given the small safety window of Fasudil, we are looking for novel ROCK inhibitors, which have similar or stronger effect on EAE with greater safety. In this study, we report that WAR-5, a Y-27632 derivative, alleviates the clinical symptoms, attenuates myelin damage and reduces CNS inflammatory responses in EAE C57BL/6 mice at an extent similar to Fasudil, while exhibits less vasodilator and adverse reaction in vivo. WAR-5 inhibits ROCK activity, and selectively suppresses the expression of ROCK II in spleen, brain and spinal cord of EAE mice, especially in spinal cord, accompanied by decreased expression of Nogo. WAR-5 also regulates the imbalance of Th1/Th17 T cells and regulatory T cells, inhibits inflammatory microenvironment induced with NF-κB-IL-1ß pathway. Importantly, WAR-5 converts M1 toward M2 microglia/macrophages that are positively correlated with BDNF and NT-3 production. Taken together, WAR-5 exhibits therapeutic potential in EAE by more selectively inhibits ROCK II, with a greater safety than Fasudil, and is worthy of further clinical study to clarify its clinical value.

Evolution of covalent networks under cooling: contrasting the rigidity window and jamming scenarios.

We study the evolution of structural disorder under cooling in supercooled liquids, focusing on covalent networks. We introduce a model for the energy of networks that incorporates weak noncovalent interactions. We show that at low temperature these interactions considerably affect the network topology near the rigidity transition that occurs as the coordination increases. As a result, this transition becomes mean field and does not present a line of critical points previously argued for, the "rigidity window." Vibrational modes are then not fractons but instead are similar to the anomalous modes observed in packings of particles near jamming. These results suggest an alternative interpretation for the intermediate phase observed in chalcogenides.

Effect of intravenous gadolinium-DTPA on diffusion-weighted imaging of brain tumors: a short temporal interval assessment.

PURPOSE: To determine the effect of intravenous administration of gadolinium (Gd) contrast medium (Gd-DTPA) on diffusion-weighted imaging (DWI) for the evaluation of normal brain parenchyma vs. brain tumor following a short temporal interval. MATERIALS AND METHODS: Forty-four DWI studies using b values of 0 and 1000 s/mm(2) were performed before, immediately after, 1 min after, 3 min after, and 5 min after the administration of Gd-DTPA on 62 separate lesions including 15 meningioma, 17 glioma and 30 metastatic lesions. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and apparent diffusion coefficient (ADC) values of the brain tumor lesions and normal brain tissues were measured on pre- and postcontrast images. Statistical analysis using paired t-test between precontrast and postcontrast data were obtained on three brain tumors and normal brain tissue. RESULTS: The SNR and CNR of brain tumors and the SNR of normal brain tissue showed no statistical differences between pre- and postcontrast (P > 0.05). The ADC values on the three cases of brain tumors demonstrated significant initial increase on the immediate time point (P < 0.01) and decrease on following the 1 min time point (P < 0.01) after contrast. Significant decrease of ADC value was still found at 3min and 5min time point in the meningioma group (P < 0.01) with gradual normalization over time. The ADC values of normal brain tissues demonstrated significant initial elevation on the immediately postcontrast DWI sequence (P < 0.01). CONCLUSION: Contrast medium can cause a slight but statistically significant change on the ADC value within a short temporal interval after the contrast administration. The effect is both time and lesion-type dependent.

Microporous Fluorinated MOF with Multiple Adsorption Sites for Efficient Recovery of C2H6 and C3H8 from Natural Gas.

Purifying C2H6/C3H8 from a ternary natural gas mixture through adsorption separation is an important but challenging process in the petrochemical industry. To address this challenge, the industry is exploring effective strategies for designing high-performance adsorbents. In this study, we present two metal-organic frameworks (MOFs), DMOF-TF and DMOF-(CF3)2, which have fluorinated pores obtained by substituting linker ligands in the host material. This pore engineering strategy not only provides suitable pore confinement but also enhances the adsorption capacities for C2H6/C3H8 by providing additional binding sites. Theoretical calculations and transient breakthrough experiments show that the introduction of F atoms not only improves the efficiency of natural gas separation but also provides multiple adsorption sites for C2H6/C3H8-framework interactions.