We identify Stoner ferromagnetism in fcc C60H(n) (n=odd) by using a local density approximation in the framework of the density functional theory. Hydrogen chemisorption on fullerenes creates quasilocalized π electrons on the fullerene surface, overlapping of their wave functions giving rise to a narrow half filled impurity band in the fcc C60H(n). The Stoner-type ferromagnetic exchange between the itinerant electrons leads to spin-split impurity bands. The magnetic moment per C60H(n) molecule is 1 μ(B) (for n=odd) or 0 (for n=even, including zero), only one of the hydrogens contributing to the spin-split states. Direct overlapping of the quasilocalized π-electron orbitals is essential for the ferromagnetism.
We developed a plasticizer composed of alkyl terminal hyperbranched polyglycerol (alkyl-HPG) for the production of non-toxic, phthalate-free flexible poly(vinyl chloride) (PVC).
Hydrogen shallow donors in undoped and doped ZnO systems have been studied by means of the electron paramagnetic resonance and nuclear magnetic resonance measurements. Experimental evidence is given in this work for coupling of hydrogen shallow donors and Mn ions in Mn-doped ZnO mediating short-range ferromagnetic spin-spin interaction.
This study aims to
develop a simple, low-cost method for synthesis
of highly branched polycaprolactone (hbPCL) for use as effective “green”
plasticizers for poly(vinyl chloride) (PVC). We demonstrate the facile
synthesis of hbPCL with tunable molecular architecture using glycidol
as a branching monomer. A series of hbPCLs is prepared via one-pot,
solvent-free copolymerization of ε-caprolactone and glycidol,
wherein the molecular architecture is readily controlled by varying
the molar ratio of glycidol to ε-caprolactone. Further, studying
the kinetics of copolymerization reveals the preferential reaction
of glycidol over ε-caprolactone, resulting in a multiarm star-like
copolymer after the ring-opening of the two monomers. The crystallization
ability of hbPCL is found to gradually weaken with the introduction
of the branching structure, and its molecular mobility is improved
substantially by esterification with butyric anhydride, following
which a maximum mobility is realized at an intermediate level of branching.
The butyl-esterified hbPCL (hbPCL-C4) is miscible with PVC, and their
mixtures have excellent flexibility comparable to that of PVC/bis(2-ethylhexyl)
phthalate (DEHP). In particular, the stretchability of PVC/hbPCL-C4
is superior to that of PVC/DEHP, owing to its better structural homogeneity.
Furthermore, PVC/hbPCL-C4 shows outstanding migration stability with
the weight loss after extraction being >85% lower than that of
PVC/DEHP.
Electrical conductivity and photoconductivity measurements were carried out on semiconducting vanadium oxide nanowire networks synthesized through the polycondensation of vanadic acid. The temperature-dependent conductivity was described well by Mott’s optical multiphonon assisted hopping model at high temperatures and by the variable-range hopping mechanism at low temperatures. The photoconductivity showed a weak temperature dependence. Besides, quasipersistent photocurrent with a single-exponential decay behavior was observed right after switching off the light and was explained in terms of the random local-potential fluctuation model.
A highly self-plasticized poly(vinyl chloride) (PVC) is demonstrated for the first time via click grafting of hyperbranched polyglycerol (HPG). The plasticizing effect of the grafted HPG on PVC is systematically investigated by various analytical methods. The amorphous and bulky dendritic structure of HPG efficiently increases the free volume of the grafted PVC, which leads to a remarkably lower glass transition temperature comparable to that of the conventional plasticized PVC. Viscoelastic analysis reveals that HPG considerably improves the softness of the grafted PVC at room temperature and promotes the segmental motion in the system. The HPG-grafted PVC films exhibit an exceptional stretchability unlike the mixture of PVC and HPG because the covalent attachment of HPG to PVC allows it to maintain its homogeneous and well-organized architecture under tensile stretching. The work provides valuable insights into the design of highly flexible and stretchable polymeric materials by means of introducing hyperbranched side chains.
In the case of colossal magnetoresistance in the perovskite manganites, "double exchange" mediated by the itinerant spins is believed to play a key role in the ferromagnetism. In contrast, the conventional "Heisenberg" interaction, i.e., direct (unmediated) interaction between the localized spins produced by the proton irradiation, is identified as the origin of proton irradiation-induced ferromagnetism in graphite.
Background
This study aims to evaluate the effect of extracorporeal shock wave therapy (ESWT) on chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and to explore the mechanism.
Methods
RWPE‐2 cells were randomly divided into three groups: (a) RWPE‐2 group (normal control), (b) LPS groups (lipopolysaccharide inducing inflammation) and (c) ESWT groups (LPS induced RWPE‐2 treated by ESWT). After ESWT was administered, cells and supernatant were collected for enzyme‐linked immunosorbent assay (ELISA) and Western blot analysis. In vivo, Sprague‐Dawley rats (n = 30) were randomly divided into three groups: (a) normal control group, (b) prostatitis groups, and (c) ESWT groups. Prostatitis rats were induced by 17 β‐estradiol and dihydrotestosterone for 4 weeks. After ESWT, prostates of each group were collected for immunohistochemistry, Western blot analysis, and ELISA.
Results
ESWT improved prostatitis by attenuating inflammation (P < .01). ESWT downregulated the expression of cyclooxygenase 2 (COX‐2) through inhibiting TLR4‐NFκB pathway compared with the LPS group in vitro or prostatitis group in vivo (P < .05). TRAF2 mediates ERK1/2‐COX2 pathway. ESWT promotes prostate tissue recovery by stimulating vascular endothelial growth factor expression (P < .01). ESWT could suppress apoptosis in the prostate.
Conclusions
ESWT improved CP/CPPS and reduced inflammation by degrading COX‐2 in microenvironment through TLR4‐NFκB‐inhibiting pathway. TRAF2 regulator in ERK1/2‐COX‐2 inhibition significantly reduced inflammation, thus suggesting ESWT may be a potential and promising treatment for CP/CPPS.
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