Seismic Performance of Multistorey Masonry Structure with Openings Repaired with CFRP Grid

FRP composites have been used for strengthening RC and masonry structures for decades. However, the researches on repairing multistorey masonry structures using FRP grids were relative less. In the present paper, an experimental study on the seismic performance of multistorey masonry structure with openings repaired with CFRP grid is introduced. Specifically, a 1/3-scale three-floor masonry wall with window openings was tested under quasistatic action to simulate the seismic damages. The damaged masonry wall was then repaired by externally bonding CFRP grids to the areas where the cracks intensively occurred. The repaired masonry wall was retested under the same loading to investigate the seismic resistance and assess the recovery attributed from the CFRP grid repairing. The findings of this study showed that CFRP grid repairing could effectively postpone or even prevent the occurrence and development of cracking. The seismic resistance of the masonry, including shear capacity, energy dissipation capacity, deformability, stiffness degradation, and ductility, was restored. The application of CFRP grid may shift the failure mechanism of the multistorey masonry wall. The recommendation of repair scheme for the similar structures was also proposed in accordance with the findings of the present work

Where is the future of China’s biogas? Review, forecast, and policy implications

This paper discusses the history and present status of different categories of biogas production in China, most of which are classified into rural household production, agriculture-based engineering production, and industry-based engineering production. To evaluate the future biogas production of China, five models including the Hubbert model, the Weibull model, the generalized Weng model, the H–C–Z model, and the Grey model are applied to analyze and forecast the biogas production of each province and the entire country. It is proved that those models which originated from oil research can also be applied to other energy sources. The simulation results reveal that China’s total biogas production is unlikely to keep on a fast-growing trend in the next few years, mainly due to a recent decrease in rural household production, and this greatly differs from the previous goal set by the official department. In addition, China’s biogas production will present a more uneven pattern among regions in the future. This paper will give preliminary explanation for the regional difference of the three biogas sectors and propose some recommendations for instituting corresponding policies and strategies to promote the development of the biogas industry in China

EUCLIA - Exploring the UV/optical continuum lag in active galactic nuclei. I. a model without light echoing

The tight inter-band correlation and the lag-wavelength relation among UV/optical continua of active galactic nuclei have been firmly established. They are usually understood within the widespread reprocessing scenario, however, the implied inter-band lags are generally too small. Furthermore, it is challenged by new evidences, such as the X-ray reprocessing yields too much high frequency UV/optical variations as well as it fails to reproduce the observed timescale-dependent color variations among {\it Swift} lightcurves of NGC 5548. In a different manner, we demonstrate that an upgraded inhomogeneous accretion disk model, whose local {\it independent} temperature fluctuations are subject to a speculated {\it common} large-scale temperature fluctuation, can intrinsically generate the tight inter-band correlation and lag across UV/optical, and be in nice agreement with several observational properties of NGC 5548, including the timescale-dependent color variation. The emergent lag is a result of the {\it differential regression capability} of local temperature fluctuations when responding to the large-scale fluctuation. An average speed of propagations as large as $\gtrsim 15\%$ of the speed of light may be required by this common fluctuation. Several potential physical mechanisms for such propagations are discussed. Our interesting phenomenological scenario may shed new light on comprehending the UV/optical continuum variations of active galactic nuclei.Comment: 18 pages, 8 figures. ApJ accepted. Further comments are very welcome

An intrinsic link between long-term UV/optical variations and X-ray loudness in quasars

Observations have shown that UV/optical variation amplitude of quasars depend on several physi- cal parameters including luminosity, Eddington ratio, and likely also black hole mass. Identifying new factors which correlate with the variation is essential to probe the underlying physical processes. Combining ~ten years long quasar light curves from SDSS stripe 82 and X-ray data from Stripe 82X, we build a sample of X-ray detected quasars to investigate the relation between UV/optical variation amplitude ($\sigma_{rms}$) and X-ray loudness. We find that quasars with more intense X-ray radiation (com- pared to bolometric luminosity) are more variable in UV/optical. Such correlation remains highly significant after excluding the effect of other parameters including luminosity, black hole mass, Ed- dington ratio, redshift, rest-frame wavelength (i.e., through partial correlation analyses). We further find the intrinsic link between X-ray loudness and UV/optical variation is gradually more prominent on longer timescales (up to 10 years in the observed frame), but tends to disappear at timescales < 100 days. This suggests a slow and long-term underlying physical process. The X-ray reprocessing paradigm, in which UV/optical variation is produced by a variable central X-ray emission illuminating the accretion disk, is thus disfavored. The discovery points to an interesting scheme that both the X-ray corona heating and UV/optical variation is quasars are closely associated with magnetic disc turbulence, and the innermost disc turbulence (where corona heating occurs) correlates with the slow turbulence at larger radii (where UV/optical emission is produced).Comment: 9 pages, 4 figures, 1 table, accepted by Ap

Topological superconductivity and large spin Hall effect in the kagome family Ti6X4 (X = Bi, Sb, Pb, Tl, In)

Topological superconductors (TSC) become a focus of research due to the accompanying Majorana fermions. However, the experimentally reported TSC are extremely rare. The recent experiments reported the kagome TSC AV$_{3}$Sb$_{5}$ (A=K, Rb, Cs), which exhibit unique superconductivity, topological surface states (TSS), and Majorana bound states. More recently, the first titanium-based kagome superconductor CsTi$_{3}$Bi$_{5}$ with nontrivial topology was successfully synthesized as a perspective TSC. Given that Cs contributes little to the electronic structures of CsTi$_{3}$Bi$_{5}$ and binary compounds may be easier to be synthesized, here, by density functional theory calculations, we predict five stable non-magnetic kagome compounds Ti$_{6}$X$_{4}$ (X = Bi, Sb, Pb, Tl, In) which exhibit superconductivity with critical temperature Tc = 3.8$-$5.1 K, nontrivial $\mathbb{Z}$$_2$ band topology, and TSS close to the Fermi level. In addition, the large intrinsic spin Hall effect is obtained in Ti$_{6}$X$_{4}$, which is caused by gapped Dirac nodes and nodal lines due to a strong spin-orbit coupling. This work offers new platforms for TSC and spintronic devices

Prevalence and spectrum of Nkx2.5 mutations associated with idiopathic atrial fibrillation

OBJECTIVE: The aim of this study was to evaluate the prevalence and spectrum of Nkx2.5 mutations associated with idiopathic atrial fibrillation (AF). METHODS: A cohort of 136 unrelated patients with idiopathic atrial fibrillation and 200 unrelated, ethnically matched healthy controls were enrolled. The coding exons and splice junctions of the Nkx2.5 gene were sequenced in 136 atrial fibrillation patients, and the available relatives of mutation carriers and 200 controls were subsequently genotyped for the identified mutations. The functional characteristics of the mutated Nkx2.5 gene were analyzed using a dual-luciferase reporter assay system. RESULTS: Two novel heterozygous Nkx2.5 mutations (p.N19D and p.F186S) were identified in 2 of the 136 unrelated atrial fibrillation cases, with a mutational prevalence of approximately 1.47%. These missense mutations co-segregated with atrial fibrillation in the families and were absent in the 400 control chromosomes. Notably, 2 mutation carriers also had congenital atrial septal defects and atrioventricular block. Multiple alignments of the Nkx2.5 protein sequences across various species revealed that the altered amino acids were completely conserved evolutionarily. Functional analysis demonstrated that the mutant Nkx2.5 proteins were associated with significantly reduced transcriptional activity compared to their wild-type counterpart. CONCLUSION: These findings associate the Nkx2.5 loss-of-function mutation with atrial fibrillation and atrioventricular block and provide novel insights into the molecular mechanism involved in the pathogenesis of atrial fibrillation. These results also have potential implications for early prophylaxis and allele-specific therapy of this common arrhythmia

PITX2C loss-of-function mutations responsible for idiopathic atrial fibrillation

OBJECTIVE: This study aimed to identify novel PITX2c mutations responsible for idiopathic atrial fibrillation. METHODS: A cohort of 210 unrelated patients with idiopathic atrial fibrillation and 200 unrelated, ethnically matched healthy individuals used as controls were recruited. The whole coding exons and splice junctions of the PITX2c gene, which encodes a paired-like homeobox transcription factor required for normal cardiovascular morphogenesis, were sequenced in 210 patients and 200 control subjects. The causative potentials of the identified mutations were automatically predicted by MutationTaster and PolyPhen-2. The functional characteristics of the PITX2c mutations were explored using a dual-luciferase reporter assay system. RESULTS: Two novel heterozygous PITX2c mutations (p.Q105L and p.R122C) were identified in 2 of the 210 unrelated patients with idiopathic atrial fibrillation. These missense mutations were absent in the 400 control chromosomes and were both predicted to be pathogenic. Multiple alignments of PITX2c protein sequences across various species showed that the altered amino acids were highly evolutionarily conserved. A functional analysis demonstrated that the mutant PITX2c proteins were both associated with significantly reduced transcriptional activity compared with their wild-type counterparts. CONCLUSION: The findings of this study associate PITX2c loss-of-function mutations with atrial fibrillation, supporting the hypothesis that dysfunctional PITX2c confers enhanced susceptibility to atrial fibrillation and suggesting potential implications for early prophylaxis and allele-specific therapy for this common arrhythmia

Salt-dependent Blood Pressure in Human Aldosterone Synthase-Transgenic Mice

Hypertension is one of the most important, preventable causes of premature morbidity and mortality in the developed world. Aldosterone is a major mineralocorticoid hormone that plays a key role in the regulation of blood pressure and is implicated in the pathogenesis of hypertension and heart failure. Aldosterone synthase (AS, cytochrome P450 11B2, cyp11B2) is the sole enzyme responsible for the production of aldosterone in humans. To determine the effects of increased expression of human aldosterone synthase (hAS) on blood pressure (BP), we established transgenic mice carrying the hAS gene (cyp11B2). We showed that hAS overexpression increased levels of aldosterone in hAS+/− mice. On high salt diet (HS), BPs of hAS+/− mice were significantly increased compared with WT mice. Fadrozole (an inhibitor of aldosterone synthase) treatment significantly reduced BPs of hAS+/− mice on HS. This is the first time overexpression of AS in a transgenic mouse line has shown an ability to induce HP. Specifically inhibiting AS activity in these mice is a promising therapy for reducing hypertension. This hAS transgenic mouse model is therefore an ideal animal model for hypertension therapy studies

A pilot study on acute inflammation and cancer: a new balance between IFN-γ and TGF-β in melanoma

Recent data have redefined the concept of inflammation as a critical component of tumor progression. However, there has been little development on cases where inflammation on or near a wound and a tumor exist simultaneously. Therefore, this pilot study aims to observe the impact of a wound on a tumor, to build a new mouse tumor model with a manufactured surgical wound representing acute inflammation, and to evaluate the relationship between acute inflammation or wound healing and the process of tumor growth. We focus on the two phases that are present when acute inflammation influences tumor. In the early phase, inhibitory effects are present. The process that produces these effects is the functional reaction of IFN-γ secretions from a wound inflammation. In the latter phase, the inhibited tumor is made resistant to IFN-γ through the release of TGF-β to balance the inflammatory factor effect on the tumor cells. A pair of cytokines IFN-γ/TGF-β established a new balance to protect the tumor from the interference effect of the inflammation. The tumor was made resistant to IFN-γ through the release of TGF-β to balance the inflammatory effect on the tumor cells. This balance mechanism that occurred in the tumor cells increased proliferation and invasion. In vitro and in vivo experiments have confirmed a new view of clinical surgery that will provide more detailed information on the evaluation of tumors after surgery. This study also provides a better understanding of the relationship between tumor and inflammation, as well as tumor cell attacks on inflammatory factors