Biodegradable magnesium‐based scaffolds present outstanding potential to revolutionize the treatment of coronary artery diseases, in which full recovery of arteries without long‐term irritation of ...implants is anticipated for averting adverse events associated with the permanent stents. However, overfast degradation of magnesium (Mg) alloys obstructs their extensive applications in terms of early structural failure and impaired biocompatibility. Herein, a facile copper‐incorporated coating system through nonaqueous phase synthesis of polydopamine is developed to facilitate Cu(II) capture along with robust film deposited on easily corrodible Mg, which subsequently enables sustained Cu(II) elution. It remarkably enhances corrosion resistance and impedes Mg degradation, which also contributes to improved, superior cytocompatibility, and abolished hemolysis. Moreover, through simultaneous control of Cu(II) and Mg(II) release to modulate the local microenvironment, a synergistic biochemical effect on desirable vascular cell selectivity is triggered for boosted endothelial cell viability and suppressed smooth muscle cell. Stent implantation into rabbit abdominal aorta thus exhibits accelerated re‐endothelialization completed in a week, and enhanced biological outcomes, alleviated complications and prolonged structural durability in 3‐month follow‐up. Collectively, this study opens up an alternative route of deploying a multifunctional surface modification strategy tailoring active interplay with the Mg matrix for better outcomes of next‐generation bioresorbable vascular stents.
With modulation effect on vessel microenvironment, coatings capable of active interaction with biodegradable matrix make significant difference on bioresorbable vascular stent performance. Cu(II)/polydopamine coating on magnesium is constructed through nonaqueous phase polymerization and demonstrates enhanced corrosion resistance for magnesium stent. It also triggers synergistic bioeffect of released Cu(II) and Mg(II) on vascular cells selectivity, thus promoting endothelialization while alleviating restenosis.
Berberrubine （BRB） is the primary metabolite of berberine （BBR） that has shown a stronger glucose-lowering effect than BBR in vivo. On the other hand, BRB is quickly and extensively metabolized into ...berberrubine-9-O-β-D-glucuronide （BRBG） in rats after oral administration. In this study we compared the pharmacokinetic properties of BRB and BRBG in rats, and explored the mechanisms underlying their glucose-lowering activities. C57BL/6 mice with HFD-induced hyperglycemia were administered BRB （50 mg·kg^-1·d^-1, ig） for 6 weeks, which caused greater reduction in the plasma glucose levels than those caused by BBR （120 mg·kg^-1·d^-1） or BRB （25 mg·kg^-1·d^-1）. In addition, BRB dose-dependently decreased the activity of α-glucosidase in gut of the mice. After oral administration of BRB in rats, the exposures of BRBG in plasma at 3 different dosages （10, 40, 80 mg/kg） and in urine at different time intervals （0-4, 4-10, 10-24 h） were dramatically greater than those of BRB. In order to determine the effectiveness of BRBG in reducing glucose levels, we prepared BRBG from the urine pool of rats, and identified and confirmed it through LC-MS-IT-TOF and NMR spectra. In human normal liver cell line 1_-02 in vitro, treatment with BRB or BRBG （5, 20, 50 pmol/L） increased glucose consumption, enhanced glycogenesis, stimulated the uptake of the glucose analog 2-NBDG, and modulated the mRNA levels of glucose-6-phosphatase and hexokinase. However, both BBR and BRB improved 2-NBDG uptake in insulin-resistant L-02 cells, while BRBG has no effect. In conclusion, BRB exerts a stronger glucose-lowering effect than BBR in HFD-induced hyperglycemia mice. Although BRB significantly stimulated the insulin sensitivity and glycolysis in vitro, BRBG may have a greater contribution to the glucose-lowering effect because it has much greater system exposure than BRB after oral administration of BRB. The results suggest that BRBG is a potential agent for reducing glucose levels.
Next‐Generation Biodegradable Vascular Stents
In article number 2205634, Jia Pei, Guang‐Yin Yuan, Jin‐Yun Tan and co‐workers report a copper‐incorporated, catechol‐based coating system on ...biodegradable magnesium‐alloy vascular stents to achieve reinforced stent structural durability, meanwhile, allowing for controlled local release of Mg(II) and Cu(II) to trigger synergistic bioeffect on rapid re‐endothelialization and alleviated neointima hyperplasia, bringing one step closer to the deployment of next‐generation biodegradable stents.
Background： Electroconvulsive therapy （ECT） can alleviate the symptoms of treatment-resistant depression （TRD）. Functional network connectivity （FNC） is a newly developed method to investigate the ...brain＇s functional connectivity patterns. The first aim of this study was to investigate FNC alterations between TRD patients and healthy controls. The second aim was to explore the relationship between the ECT treatment response and pre-ECT treatment FNC alterations in individual TRD patients. Methods： This study included 82 TRD patients and 41 controls. Patients were screened at baseline and after 2 weeks of treatment with a combination of ECT and antidepressants. Group information guided-independent component analysis （G1G-ICA） was used to compute subject-specific functional networks （FNs）. Grassmann maniibld and step-wise forward component selection using support vector machines were adopted to perform the FNC measure and extract the functional networks＇ connectivity patterns （FCP）. Pearson＇s correlation analysis was used to calculate the correlations between the FCP and ECT response. Results： A total of 82 TRD patients in the ECT group were successfully treated. On an average, 8.50 ~ 2.00 ECT sessions were conducted. After ECT treatment, only 42 TRD patients had an improved response to ECT （the Hamilton scores reduction rate was more than 50%）, response rate 51%. 8 FNs （anterior and posterior default mode network, bilateral frontoparietal network, audio network, visual network, dorsal attention network, and sensorimotor network） were obtained using GIG-ICA. We did not found that FCPs were significantly different between TRD patients and healthy controls. Moreover, the baseline FCP was unrelated to the ECT treatment response. Conclusions： The FNC was not significantly different between the TRD patients and healthy controls, and the baseline FCP was unrelated to the ECT treatment response. These findings will necessitate that we modify the experimental scheme to explore the mechanisms underlying ECT＇s effects on depression and explore the specific predictors of the effects of ECT based on the pre-ECT treatment magnetic resonance imaging.
Crystal orientation and melting behavior of poly（e-caprolactone） in a diblock copolymer of poly（e-caprolactone）- block-poly（2,5-bis4-methoxyphenyloxycarbonyl）styrene） （PCL-b-PMPCS） was investigated. ...The degrees of polymerization of the PCL and PMPCS block are 200 and 98, respectively. With the PMPCS in a columnar liquid crystalline phase, the diblock is rod-coil one, which exhibits a lamellar phase morphology with the PCL layer thickness of 15.2 nm. Since the glass transition temperature of PMPCS block is much higher than the melting temperature of PCL, the crystallization of PCL is in a one-dimensionally ＂hard＂ confinement environment. Mainly on the basis of two-dimensional wide-angle X-ray diffraction experiments, we identified the orientation of PCL isothermally crystallized at various crystallization temperatures （Tos）. At high Tcs （To 〉 10 ℃）, the c-axis of the PCL crystal is along the layer normal of the microphase-separated sturcture. Decreasing Tc can result in the tilting of PCL c-axis with respect to the layer normal. The lower the Tc is, the more the c-axis inclines. Meanwhile, the b-axis of PCL remains perpendicular to the layer normal. At a very low Tc of-78 ℃, the orientation of the PCL crystals is completely random. For the samples isothermally crystallized at Tc 〈 10 ℃, double melting behavior can be observed. While the low temperature endotherm reflects the melting of the crystals originally formed at the Tc applied, the high temperature one is associated with the crystals subjected to the process of recrystallization/reorganization upon heating due to the annealing effect.
We apply perturbative QCD to investigate the near threshold heavy quarkonium photoproduction at large momentum transfer. From an explicit calculation, we show that the conventional power counting ...method will be modified and the three quark Fock state with nonzero orbital angular momentum dominates the near threshold production. It carries a power behavior of 1/(−t)5 for the differential cross section. We further comment on the impact of our results on the interpretation of the experiment measurement in terms of the gluonic gravitational form factors of the proton.
We perform a perturbative QCD analysis of the gluonic gravitational form factors (GFFs) of the proton and pion at large momentum transfer. We derive the explicit factorization formula of the GFFs in ...terms of the distribution amplitudes of hadrons. At the leading power, we find that the gluon GFFs Ag and Cg scale as Agπ(t)=Cgπ(t)∼1/(−t) for pion, Agp(t)∼1/(−t)2 and Cgp(t)∼ln2(−t/Λ2)/(−t)3 for proton, respectively, where t is the momentum transfer and Λ a non-perturbative scale to regulate the endpoint singularity in Cgp calculation. Our results provide a unique perspective of the momentum dependence of the GFFs and will help to improve our understanding of the internal pressure distributions of hadrons.
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bstract
We perform a perturbative QCD analysis of the gravitational form factors (GFFs) of nucleon at large momentum transfer. We derive the explicit factorization formula of the GFFs in terms of ...twist-3 and twist-4 light-cone distribution amplitudes of nucleon. Power behaviors for these GFFs are obtained from the leading order calculations. Numeric results of the quark and gluon contributions to various GFFs are presented with model assumptions for the distribution amplitudes in the literature. We also present the perturbative calculations of the scalar form factor 〈
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〉 for pion and proton at large momentum transfer.
To inhibit the graphitization of diamond under high temperature and low pressure, diamond/SiC composites were firstly fabricated by a rapid gaseous Si vacuum reactive infiltration process. The ...microstructure and graphitization behavior of diamond in the composites under various infiltration temperatures and holding time were investigated. The thermal conductivity of the resul- tant materials was discussed. The results show that the diamond-to-graphite transition is effectively inhibited at temperature of as high as 1600 ℃ under vacuum, and the substantial graphitization starts at 1700 ℃. The microstructure of those ungraphitized samples is uniform and fully densified. The inhibition mechanisms of graphitization include the isolation of the catalysts from diamond by a series of protective layers, high pressure stress applied on diamond by the reaction-bonded SiC, and the moderate gas-solid reaction. For the graphitized samples, the boundary between diamond and SiC is coarse and loose. The graphitization mechanism is considered to be an initial detachment of the bilayers from the diamond surfaces, and subsequently flattening to form graphite. The ungraphitized samples present higher thermal conductivity of about 410 W.m-1.K-1 due to the fine interfacial structure. For the graphitized samples, the thermal conductivity decreases significantly to 285 W.m-1.K-1 as a result of high interfacial thermal resistance.
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