Two positive solutions for second-order quasilinear differential equation boundary value problems with sign changing nonlinearities

AbstractIn this paper, the second order quasilinear differential equation (Φ(y′))′+q(t)f(t,y)=0,0<t<1 subject to Dirichlet boundary conditions and mixed boundary conditions is studied, where f is allowed to change sign, Φ(v)=|v|p−2v,p>1. We show the existence of at least two positive solutions by using a new fixed point theorem in cones

Inactivation of the MDM2 RING domain enhances p53 transcriptional activity in mice

The MDM2 RING domain harbors E3 ubiquitin ligase activity critical for regulating the degradation of tumor suppressor p53, which controls many cellular pathways. The MDM2 RING domain also is required for an interaction with MDMX. Mice containing a substitution in the MDM2 RING domain, MDM2C462A, disrupting MDM2 E3 function and the MDMX interaction, die during early embryogenesis that can be rescued by p53 deletion. To investigate whether MDM2C462A, which retains p53 binding, has p53-suppressing activity, we generated Mdm2C462A/C462A;p53ER/- mice, in which we replaced the endogenous p53 alleles with an inducible p53ER/- allele, and compared survival with that of similarly generated Mdm2-/-;p53ER/- mice. Adult Mdm2-null mice died ~7 days after tamoxifen-induced p53 activation, indicating that in the absence of MDM2, MDMX cannot suppress p53. Surprisingly, Mdm2C462A/C462A;p53ER/- mice died ~5 days after tamoxifen injection, suggesting that p53 activity is higher in the presence of MDM2C462A than in the absence of MDM2. Indeed, in MDM2C462A-expressing mouse tissues and embryonic fibroblasts, p53 exhibited higher transcriptional activity than in those expressing no MDM2 or no MDM2 and MDMX. This observation indicated that MDM2C462A not only is unable to suppress p53 but may have gained the ability to enhance p53 activity. We also found that p53 acetylation, a measure of p53 transcriptional activity, was higher in the presence of MDM2C462A than in the absence of MDM2. These results reveal an unexpected role of MDM2C462A in enhancing p53 activity and suggest the possibility that compounds targeting MDM2 RING domain function could produce even more robust p53 activation

Double Dome and Reemergence of Superconductivity in Pristine 6R-TaS2 under Pressure

Investigating the implications of interlayer coupling on superconductivity is essential for comprehending the intrinsic mechanisms of high temperature superconductors. Van der Waals heterojunctions have attracted extensive research due to their exotic interlayer coupling. Here, we present a natural heterojunction superconductor of 6R-TaS2 that demonstrates a double-dome of superconductivity, in addition to, the reemergence of superconducting under high pressures. Our first principles calculation shows that the first dome of superconductivity in 6R-TaS2 can be attributed to changes in interlayer coupling and charge transfer. The second superconducting dome and the reemergence of superconductivity can be ascribed to changes in the density of states resulting from Fermi surface reconstruction, in which the DOS of T-layer and S p-orbitals play a crucial role. We have reported the first observation in TMDs that non-metallic atoms playing a dominant role in the reemergence of superconducting and the influence of two Lifshitz transitions on superconducting properties

Two positive solutions for second-order quasilinear differential equation boundary value problems with sign changing nonlinearities

AbstractIn this paper, the second order quasilinear differential equation (Φ(y′))′+q(t)f(t,y)=0,0<t<1 subject to Dirichlet boundary conditions and mixed boundary conditions is studied, where f is allowed to change sign, Φ(v)=|v|p−2v,p>1. We show the existence of at least two positive solutions by using a new fixed point theorem in cones

Antioksidacijska aktivnost produkata enzimske hidrolize pšeničnih mekinja

Wheat bran was destarched and deproteinated by α-amylase, protease and amyloglucosidase successively, and further hydrolyzed using Bacillus subtilis xylanases. The yield of enzymatic hydrolysates from wheat bran (EHWB) was 1.84 %. The total phenolics were 0.3712 g of ferulic acid equivalents per gram of EHWB. The antioxidant potency of EHWB was evaluated using different assays, such as iron ion chelation, reducing power, scavenging activity against 2,2’-diphenyl-1-picrylhydrazyl (DPPH) and reactive oxygen species under in vitro conditions. EHWB exhibited an effective ferrous ion chelating activity and strong reducing power. It also showed a high DPPH radical scavenging activity (89.4 %) at 5.0 mg/mL, which was comparable to that of the synthetic antioxidant, butylated hydroxytoluene. EHWB also exerted a marked scavenging effect on ·OH with an EC50 value of 0.46 mg/mL, which was lower than that of mannitol (1.03 mg/mL), a classical hydroxyl radical scavenger, and obvious antioxidant activities toward O2·- and H2O2.Iz pšeničnih su mekinja djelovanjem enzima α-amilaze, proteaze i amiloglukozidaze uklonjeni škrob i proteini, nakon čega je provedena hidroliza pomoću ksilanaze iz bakterije Bacillus subtilis, te ostvaren prinos enzimskih hidrolizata od 1,84 %. Dobiven je udio ukupnih fenola od 0,3712 grama ekvivalenta ferulične kiseline po gramu hidrolizata. Primjenom različitih metoda ispitana je antioksidacijska sposobnost hidrolizata in vitro, tj. sposobnost stvaranja kelata s Fe2+ ionima, redukcije Fe3+ iona, te uklanjanja DPPH radikala i reaktivnih ugljikovih spojeva. Ispitani su hidrolizati imali dobru moć redukcije Fe3+ iona i stvaranja kelata s ionima Fe2+. Pri koncentraciji od 5 mg/L pokazali su vrlo dobru sposobnost uklanjanja DPPH radikala (89,4 %), približnu onoj sintetskog oksidansa (butiliranog hidroksitoluena). Isto tako su odlično uklanjali i hidroksilne radikale (EC50=0,46 mg/mL), puno bolje od manitola (EC50=1,03 mg/mL) koji se uobičajeno koristi za njihovo uklanjanje. Dobiveni enzimski hidrolizati su također imali antioksidacijski učinak protiv superoksidnih radikala i vodikova peroksida

Superconducting Zirconium Polyhydrides at Moderate Pressures.

Highly compressed hydrides have been at the forefront of the search for high-Tc superconductivity. The recent discovery of record-high Tc's in H3S and LaH10±x under high pressure fuels the enthusiasm for finding good superconductors in similar hydride groups. Guided by first-principles structure prediction, we successfully synthesized ZrH3 and Zr4H15 at modest pressures (30-50 GPa) in diamond anvil cells by two different reaction routes: ZrH2 + H2 at room temperature and Zr + H2 at ∼1500 K by laser heating. From the synchrotron X-ray diffraction patterns, ZrH3 is found to have a Pm3̅n structure corresponding to the familiar A15 structure, and Zr4H15 has an I4̅3d structure isostructural to Th4H15. Electrical resistance measurement and the dependence of Tc on the applied magnetic field of the sample showed the emergence of two superconducting transitions at 6.4 and 4.0 K at 40 GPa, which correspond to the two Tc's for ZrH3 and Zr4H15.This work was supported by the National Key R&D Program of China (No. 2018YFA0305900), National Natural Science Foundation of China (Nos. 51632002, 11674122, 51572108, and 11504127), Program for Changjiang Scholars and Innovative Research Team in University (No. IRT_15R23), the 111 Project (No. B12011), and the Natural Sciences and Engineering Research Council of Canada (NSERC). C.J.P. acknowledges financial support from the Engineering and Physical Sciences Research Council (Grant EP/P022596/1) and a Royal Society Wolfson Research Merit award

Polyhydride CeH9 with an atomic-like hydrogen clathrate structure.

Compression of hydrogen-rich hydrides has been proposed as an alternative way to attain the atomic metallic hydrogen state or high-temperature superconductors. However, it remains a challenge to get access to these states by synthesizing novel polyhydrides with unusually high hydrogen-to-metal ratios. Here we synthesize a series of cerium (Ce) polyhydrides by a direct reaction of Ce and H2 at high pressures. We discover that cerium polyhydride CeH9, formed above 100 GPa, presents a three-dimensional hydrogen network composed of clathrate H29 cages. The electron localization function together with band structure calculations elucidate the weak electron localization between H-H atoms and confirm its metallic character. By means of Ce atom doping, metallic hydrogen structure can be realized via the existence of CeH9. Particularly, Ce atoms play a positive role to stabilize the sublattice of hydrogen cages similar to the recently discovered near-room-temperature lanthanum hydride superconductors

Hyperprogressive disease in non-small cell lung cancer after PD-1/PD-L1 inhibitors immunotherapy: underlying killer

Immune checkpoint inhibitors (ICIs) target the negative regulatory pathway of T cells and effectively reactive the anti-tumor immune function of T cells by blocking the key pathway of the immune escape mechanism of the tumor—PD-1/PD-L1, and fundamentally changing the prospect of immunotherapy for non-small cell lung cancer patients. However, such promising immunotherapy is overshadowed by Hyperprogressive Disease, a response pattern associated with unwanted accelerated tumor growth and characterized by poor prognosis in a fraction of treated patients. This review comprehensively provides an overview of Hyperprogressive Disease in immune checkpoint inhibitor-based immunotherapy for non-small cell lung cancer including its definition, biomarkers, mechanisms, and treatment. A better understanding of the black side of immune checkpoint inhibitors therapy will provide a more profound insight into the pros and cons of immunotherapy

Configuration of Coupling Methanol Steam Reforming over Cu-Based Catalyst in a Synthetic Palladium Membrane for One-Step High Purity Hydrogen Production

Methanol steam reforming coupled with an efficient hydrogen purification technology to produce high purity hydrogen that feeds for hydrogen fuel cells is an attractive approach to realizing distributed power generation. However, the harmony of catalytic reforming and hydrogen separation with respect to thermodynamics is still an issue. In this work, in order to construct an integrated methanol steam reforming (MSR) reactor for high purity hydrogen production, CuCe/Al2O3 was synthesized by a hydrothermal-impregnated method and a Pd membrane supported by a porous ceramic using the electroless plating method. The results revealed that the catalytic activity and high temperature stability for methanol steam reforming were evidently improved by tuning the copper dispersion, porous structure and the crystal phase. The coupling range with palladium membrane operating temperature was widened. CuCe/Al2O3 presented an excellent stability with a better carbon deposition resistance for the long-term tests than Cu/Al2O3, which exhibited 836.68 μmol/gcat. min of H2 production with low carbon deposition (3.38 wt%) and lower CO emission (0.48 vol%). A 10 μm thick Pd membrane that was deposited on the ceramic support displayed dense and even surface morphology. The effect of palladium membrane structure on hydrogen separation was analyzed. In addition, the influence of temperature on coupling was discussed. Ultimately, high purity of H2 (99.36 vol%) was achieved at 400 °C by integrating the Pd membrane reactor with methanol steam reforming. The internal temperature distribution of the reactor and the effects of feeding conditions were also investigated. This work might offer certain reference for the development of the future distributed integrated hydrogen power generation system, especially in the application of electric vehicles and on-site electricity

Ferromagnetic-antiferromagnetic coexisting ground states and exchange bias effects in MnBi4Te7\bf{MnBi_4Te_7} and MnBi6Te10\bf{MnBi_6Te_{10}}

Natural superlattice structures $\rm{(MnBi_2Te_4)(Bi_2Te_3)}$$_n$ ($n$ = 1, 2,...), in which magnetic $\rm{MnBi_2Te_4}$ layers are separated by nonmagnetic $\rm{Bi_2Te_3}$ layers, hold band topology, magnetism and reduced interlayer coupling, providing a promising platform for the realization of exotic topological quantum states. However, their magnetism in the two-dimensional limit, which is crucial for further exploration of quantum phenomena, remains elusive. Here, complex ferromagnetic (FM)-antiferromagnetic (AFM) coexisting ground states that persist up to the 2-septuple layers (SLs) limit are observed and comprehensively investigated in $\rm{MnBi_4Te_7}$ ($n$ = 1) and $\rm{MnBi_6Te_{10}}$ ($n$ = 2). The ubiquitous Mn-Bi site mixing modifies or even changes the sign of the subtle inter-SL magnetic interactions, yielding a spatially inhomogeneous interlayer coupling. Further, a tunable exchange bias effect is observed in $\rm{(MnBi_2Te_4)(Bi_2Te_3)}$$_n$ ($n$ = 1, 2), arising from the coupling between the FM and AFM components in the ground state. Our work highlights a new approach toward the fine-tuning of magnetism and paves the way for further study of quantum phenomena in $\rm{(MnBi_2Te_4)(Bi_2Te_3)}$$_n$ ($n$ = 1, 2,...) as well as their magnetic applications.Comment: 9 pages, 4 figure