411 research outputs found
Self-Organized Time Crystal in Driven-Dissipative Quantum System
Continuous time crystals (CTCs) are characterized by sustained oscillations
that break the time translation symmetry. Since the ruling out of equilibrium
CTCs by no-go theorems, the emergence of such dynamical phases has been
observed in various driven-dissipative quantum platforms. The current
understanding of CTCs is mainly based on mean-field (MF) theories, which fail
to address the problem of whether the long-range time crystalline order exists
in noisy, spatially extended systems without the protection of all-to-all
couplings. Here, we propose a new kind of CTC realized in a quantum contact
model through self-organized bistability (SOB). The exotic CTCs stem from the
interplay between collective dissipation induced by the first-order absorbing
phase transitions (APTs) and slow constant driving provided by an incoherent
pump. The stability of such oscillatory phases in finite dimensions under the
action of intrinsic quantum fluctuations is scrutinized by the functional
renormalization group method and numerical simulations. Occurring at the edge
of quantum synchronization, the CTC phase exhibits an inherent period and
amplitude with a coherence time diverging with system size, thus also
constituting a boundary time crystal (BTC). Our results serve as a solid route
towards self-protected CTCs in strongly interacting open systems.Comment: 15 pages, 7 figure
Studies Based on Preparation, Physical Characteristics, and Cellular Pharmacological Activities of Thin PLGA Film Loaded with Geniposide
In this primary study, thin polylactic-co-glycolic acid (PLGA) film loaded with geniposide was first prepared and demonstrated on both physical and pharmacological aspects for its potential application on drug-eluting vascular stents. Physical parameters of geniposide-loaded thin film, such as crystal structure, molecular spectral characteristics, and release behavior in the whole process were detected. From X-Ray diffraction, the characteristic peak of crystal geniposide disappeared on geniposide-loaded PLGA film (GLPF) after it formed, which meant there was no agglomeration phenomenon, as geniposide was distributed in the form of single molecule. According to scanning electron microscopy (SEM) figure, the GLPF was more flat and uniform with better compactness. It inferred that release behavior of geniposide at the early stage (0~15 d) was in the form of free diffusion. Carrier PLGA began to degrade 15 days later, so the residual geniposide was also dissolved. Cellular pharmacological effects of geniposide on endothelial cells (ECs) and smooth muscle cells (SMCs) were also demonstrated on GLPF. 5% and 10% (w/w) geniposide-loaded PLGA (60 : 40) membrane indicated its significant effect on ECs promotion and SMCs inhibition. All provided feasible evidences for the development of new geniposide-coating vascular stent using PLGA as carrier
Lightest Higgs boson decays in the from supersymmetric standard model
We study the lightest Higgs boson decays in the framework
of the from supersymmetric standard model (SSM), where
is a vector meson . Compared to the minimal
supersymmetric standard model (MSSM), the SSM introduces three
right-handed neutrino superfields, which lead to the mixing of the Higgs
doublets with the sneutrinos. The mixing affects the lightest Higgs boson mass
and the Higgs couplings. Compared to the standard model, the SSM can
give large new physics contributions to the decay width of in
suitable parameter space, which may be detected by the HL-LHC or the other
future high energy colliders.Comment: 15 pages, 5 figures. arXiv admin note: substantial text overlap with
arXiv:2002.0437
No safe renal warm ischemia time—The molecular network characteristics and pathological features of mild to severe ischemia reperfusion kidney injury
Ischemic acute kidney injury (AKI) has always been a hot and difficult research topic in the field of renal diseases. This study aims to illustrate the safe warm ischemia time of kidney and the molecular network characteristics and pathological features of mild to severe ischemia reperfusion kidney injury. We established varying degrees of renal injury due to different ischemia time (0 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, and 30 min) on unilateral (left kidney) ischemia-reperfusion injury and contralateral (right kidney) resection (uIRIx) mouse model. Mice were sacrificed 24 h after uIRIx, blood samples were harvested to detect serum creatinine (Scr), and kidney tissue samples were harvested to perform Periodic Acid-Schiff (PAS) staining and RNA-Seq. Differentially expressed genes (DEGs) were identificated, time-dependent gene expression patterns and functional enrichment analysis were further performed. Finally, qPCR was performed to validated RNA-Seq results. Our results indicated that there was no absolute safe renal warm ischemia time, and every minute of ischemia increases kidney damage. Warm ischemia 26min or above in mice makes severe kidney injury, renal pathology and SCr were both significantly changed. Warm ischemia between 18 and 26 min makes mild kidney injury, with changes in pathology and renal molecular expression, while SCr did not change. No obvious pathological changes but significant differences in molecular expression were found less than 16min warm ischemia. There are two key time intervals in the process of renal ischemia injury, 0 min–16 min (short-term) and 26 min–28 min (long-term). Gene expression of immune-related pathways were most significantly down-regulated in short-term ischemia, while metabolism-related pathways were the mainly enriched pathway in long-term ischemia. Taken together, this study provides novel insights into safe renal artery occlusion time in partial nephrectomy, and is of great value for elucidating molecular network characteristics and pathological features of mild to severe ischemia reperfusion kidney injury, and key genes related to metabolism and immune found in this study also provide potential diagnostic and therapeutic biomarkers for AKI
The Non-local Kardar-Parisi-Zhang Equation With Spatially Correlated Noise
The effects of spatially correlated noise on a phenomenological equation
equivalent to a non-local version of the Kardar-Parisi-Zhang equation are
studied via the dynamic renormalization group (DRG) techniques. The correlated
noise coupled with the long ranged nature of interactions prove the existence
of different phases in different regimes, giving rise to a range of roughness
exponents defined by their corresponding critical dimensions. Finally
self-consistent mode analysis is employed to compare the non-KPZ exponents
obtained as a result of the long range -long range interactions with the DRG
results.Comment: Plain Latex, 10 pages, 2 figures in one ps fil
An ammonium iron(II) pyrophosphate, (NH4)2[Fe3(P2O7)2(H2O)2], with a layered structure
Diammonium diaquabis(phosphato)triferrate(II), (NH4)2[Fe3(P2O7)2(H2O)2], was synthesized under solvothermal conditions at 463 K. The crystal structure, isotypic to its Mn and Ni analogues, is built from iron pyrophosphate layers parallel to (100), which are linked by ammonium ions sitting in the interlayer space via O—H⋯O and N—H⋯O hydrogen bonds. There are two crystallographic Fe sites in the crystal structure, one at a special position (2a, ), the other at a general position (4e, 1). The former Fe atom on the inversion centre is coordinated by six O atoms, forming an FeO6 octahedron, while the latter is coordinated by five phosphate O atoms and one water molecule, forming an FeO5(H2O) octahedron. Each FeO6 octahedron shares trans edges with two FeO5(H2O) octahedra, forming a linear trimeric unit. These trimers share the lateral edges of FeO5(H2O) with other trimers, forming a zigzag chain running along [010]. The zigzag chains are further linked by P2O7 groups into a layered structure parallel to (100)
Tetraaquatetramanganese(II) catena-[germanodihydroxidodi(hydrogenphosphate)diphosphate]
The title compound, Mn4(H2O)4[Ge(OH)2(HPO4)2(PO4)2], was synthesized by the solvothermal method. Its crystal structure is isotypic with the iron and cobalt analogues [Huang et al. (2012 ▶). Inorg. Chem.
51, 3316–3323]. In the crystal structure, the framework is built from undulating manganese phosphate sheets parallel to (010) interconnected by GeO6 octahedra (at the inversion center), resulting in a three-dimensional network with eight-membered ring channels into which all the protons point. The undulating manganese phosphate sheet consists of zigzag manganese octahedral chains along [10-1], built from MnO4(OH)(OH2) octahedra and MnO5(OH2) octahedra by sharing their trans or skew edges, which are interconnected by PO3(OH) and PO4 tetrahedra via corner-sharing. The crystal structure features extensive O—H⋯O hydrogen-bonding interactions
Characterization of Arabidopsis thaliana Hydroxyphenylpyruvate Reductases in the Tyrosine Conversion Pathway
Tyrosine serves as a precursor to several types of plant natural products of medicinal or nutritional interests. Hydroxyphenylpyruvate reductase (HPPR), which catalyzes the reduction of 4-hydroxyphenylpyruvic acid (pHPP) to 4-hydroxyphenyllactic acid (pHPL), has been shown to be the key enzyme in the biosynthesis of rosmarinic acid (RA) from tyrosine and, so far, HPPR activity has been reported only from the RA-accumulating plants. Here, we show that HPPR homologs are widely distributed in land plants. In Arabidopsis thaliana, which does not accumulate RA at detectable level, two homologs (HPPR2 and HPPR3) are functional in reducing pHPP. Phylogenetic analysis placed HPPR2 and HPPR3 in two separate groups within the HPPR clade, and HPPR2 and HPPR3 are distinct from HPR1, a peroxisomal hydroxypyruvate reductase (HPR). In vitro characterization of the recombinant proteins revealed that HPPR2 has both HPR and HPPR activities, whereas HPPR3 has a strong preference for pHPP, and both enzymes are localized in the cytosol. Arabidopsis mutants defective in either HPPR2 or HPPR3 contained lower amounts of pHPL and were impaired in conversion of tyrosine to pHPL. Furthermore, a loss-of-function mutation in tyrosine aminotransferase (TAT) also reduced the pHPL accumulation in plants. Our data demonstrate that in Arabidopsis HPPR2 and HPPR3, together with TAT1, constitute to a probably conserved biosynthetic pathway from tyrosine to pHPL, from which some specialized metabolites, such as RA, can be generated in specific groups of plants. Our finding may have broad implications for the origins of tyrosine-derived specialized metabolites in general
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