The Υ(1S)\Upsilon(1S) leptonic decay using the principle of maximum conformality

In the paper, we study the $\Upsilon(1S)$ leptonic decay width $\Gamma(\Upsilon(1S)\to \ell^+\ell^-)$ by using the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct momentum flow of the process, whose value is independent to the choice of the renormalization scale and its prediction thus avoids the conventional renormalization scale ambiguities. Using the known next-to-next-to-next-to-leading order perturbative series together with the PMC single scale-setting approach, we do obtain a renormalization scale independent decay width, $\Gamma_{\Upsilon(1S) \to e^+ e^-} = 1.262^{+0.195}_{-0.175}$ keV, where the error is squared average of those from $\alpha_s(M_{Z})=0.1181\pm0.0011$, $m_b=4.93\pm0.03$ GeV and the choices of factorization scales within $\pm 10\%$ of their central values. To compare with the result under conventional scale-setting approach, this decay width agrees with the experimental value within errors, indicating the importance of a proper scale-setting approach.Comment: 6 pages, 4 figure

Pyrrolidine Dithiocarbamate Attenuates Paraquat-Induced Lung Injury in Rats

Paraquat (PQ) has been demonstrated that the main target organ for the toxicity is the lung. This study aimed to investigate the potential protective effect of PDTC on the PQ-induced pulmonary damage. Fifty-four rats were divided into control, PQ-treated and PQ+PDTC-treated groups. Rats in the PQ group were administrated 40 mg/kg PQ by gastric gavage, and PDTC group with 40 mg/kg PQ followed by injection of 120 mg/kg PDTC (IP). On the days 3, 7, 14 and 21 after treatments, the activities of GSH-Px, SOD, MDA level and the content of HYP were measured. TGF-β1 mRNA and protein were assayed by RT-PCR and ELISA. MDA level in plasma and BALF was increased and the activities of GSH-Px and SOD were decreased significantly in the PQ-treated groups (P < .05) compared with control group. While the activities of GSH-Px and SOD in the PQ+PDTC-treated groups was markedly higher than that of PQ-treated groups (P < .05), and in contrast, MDA level was lower. TGF-β1 mRNA and protein were significantly lower in the PQ+PDTC-treated groups than that of PQ-treated groups (P < .05). The histopathological changes in the PQ+PDTC-treated groups were milder than those of PQ groups. Our results suggested that PDTC treatment significantly attenuated paraquat-induced pulmonary damage

Cosmological Interpretation for the Stochastic Signal in Pulsar Timing Arrays

The pulsar timing array (PTA) collaborations have recently provided compelling evidence for the presence of a stochastic signal consistent with a gravitational-wave background. In this letter, we combine the latest data sets from NANOGrav, PPTA and EPTA collaborations to explore the cosmological interpretations for the detected signal from first-order phase transitions, domain walls and cosmic strings separately. We find that the first-order phase transitions and cosmic strings can give comparable interpretations compared to supermassive black hole binaries (SMBHBs) characterized by a power-law spectrum, but the domain wall model is strongly disfavored with the Bayes factor compared to the SMBHBs model being 0.009. Furthermore, the constraints on the parameter spaces indicate that: 1) a strong phase transition at temperatures below the electroweak scale is favored and the bubble collisions make the dominant contribution to the energy spectrum; 2) the cosmic string tension is $G \mu \in [1.46, 15.3]\times 10^{-12}$ at $90\%$ confidence interval and a small reconnection probability $p<6.68\times 10^{-2}$ is preferred at $95\%$ confidence level, implying that the strings in (super)string theory are strongly preferred than the classical field strings.Comment: 10 pages, 5 figures, 2 table

Searching for Isotropic Stochastic Gravitational-Wave Background in the International Pulsar Timing Array Second Data Release

We search for isotropic stochastic gravitational-wave background (SGWB) in the International Pulsar Timing Array second data release. By modeling the SGWB as a power-law, we find very strong Bayesian evidence for a common-spectrum process, and further this process has scalar transverse (ST) correlations allowed in general metric theory of gravity as the Bayes factor in favor of the ST-correlated process versus the spatially uncorrelated common-spectrum process is $30\pm 2$. The median and the $90\%$ equal-tail amplitudes of ST mode are $\mathcal{A}_{\mathrm{ST}}= 1.29^{+0.51}_{-0.44} \times 10^{-15}$, or equivalently the energy density parameter per logarithm frequency is $\Omega_{\mathrm{GW}}^{\mathrm{ST}} = 2.31^{+2.19}_{-1.30} \times 10^{-9}$, at frequency of 1/year. However, we do not find any statistically significant evidence for the tensor transverse (TT) mode and then place the $95\%$ upper limits as $\mathcal{A}_{\mathrm{TT}}< 3.95 \times 10^{-15}$, or equivalently $\Omega_{\mathrm{GW}}^{\mathrm{TT}}< 2.16 \times 10^{-9}$, at frequency of 1/year.Comment: 7 pages, 4 figures, 3 table

Distinct different expression of Th17 and Th9 cells in coxsackie virus B3-induced mice viral myocarditis

<p>Abstract</p> <p>Background</p> <p>Recently, a new subset of CD4⁺T helper(Th) cell that predominantly secret cytokine interleukin-9(IL-9) is identified, termed Th9 cell. It has been reported to participate in tissue inflammation and autoimmune responses, and induce disease which differed from Th17 cells. Th17 cells have been shown to play a critical role in viral myocarditis (VMC), but whether Th9 cells are involved in the pathogenesis of VMC remains unclear.</p> <p>Results</p> <p>BALB/c mice were intraperitoneally (i.p) injected with coxsackie virus B3(CVB3) for establishing VMC models. Control mice were treated with phosphate-buffered saline i.p. On day 0,7,14,21,28,35,42 after injection, myocardial histopathological changes were evaluated by hematoxylin-eosin staining. Splenic Th17 and Th9 cells subsets were analyzed by flow cytometry. And cardiac IL-17, IL-9 mRNA were measured by semi-quantitative reverse transcription-PCR and nested PCR, respectively. Results showed the levels of Th17 cells and IL-17 mRNA obviously increased in VMC mice on 7 day after infection, peaked on day 28, and highly persisted to at least day 42 (p < 0.05). While the frequencies of Th9 cells and IL-9 mRNA showed no significant difference between VMC and control group throughout the course of the experiment(p > 0.05).</p> <p>Conclusions</p> <p>It was differentiated Th17 but not Th9 cells significantly elevated in the development of CVB3-induced VMC. The microenvironment of VMC seemed to contribute to the differentiation and proliferation of Th17 rather than Th9 cells. Our preliminary data implied Th9 cells could not protect against VMC nor promote the disease.</p

The thermal and electrical properties of the promising semiconductor MXene Hf2CO2

In this work, we investigate the thermal and electrical properties of oxygen-functionalized M2CO2 (M = Ti, Zr, Hf) MXenes using first-principles calculations. Hf2CO2 is found to exhibit a thermal conductivity better than MoS2 and phosphorene. The room temperature thermal conductivity along the armchair direction is determined to be 86.25-131.2 Wm-1K-1 with a flake length of 5-100 um, and the corresponding value in the zigzag direction is approximately 42% of that in the armchair direction. Other important thermal properties of M2CO2 are also considered, including their specific heat and thermal expansion coefficients. The theoretical room temperature thermal expansion coefficient of Hf2CO2 is 6.094x10-6 K-1, which is lower than that of most metals. Moreover, Hf2CO2 is determined to be a semiconductor with a band gap of 1.657 eV and to have high and anisotropic carrier mobility. At room temperature, the Hf2CO2 hole mobility in the armchair direction (in the zigzag direction) is determined to be as high as 13.5x103 cm2V-1s-1 (17.6x103 cm2V-1s-1), which is comparable to that of phosphorene. Broader utilization of Hf2CO2 as a material for nanoelectronics is likely because of its moderate band gap, satisfactory thermal conductivity, low thermal expansion coefficient, and excellent carrier mobility. The corresponding thermal and electrical properties of Ti2CO2 and Zr2CO2 are also provided here for comparison. Notably, Ti2CO2 presents relatively low thermal conductivity and much higher carrier mobility than Hf2CO2, which is an indication that Ti2CO2 may be used as an efficient thermoelectric material.Comment: 26 pages, 5 figures, 2 table

Distribution and metabolism of ascorbic acid in pear fruits (Pyrus pyrifolia Nakai cv. Aikansui)

Ascorbate accumulation levels, distribution and key enzyme activities involved in synthesizing via Smirnoff-Wheeler pathway and recycling in different pear fruit tissues during development were studied. Results show that the ascorbate contents increased with the fruit development, and reached the highest titers in 30 days after anthesis (DAA), then decreased and maintained a level. The higher contents of ascorbate in the peel of pear fruit were observed, which results from a combination of higher activities of L-galactose dehydrogenase (GalDH) and L-galactono-1,4-lactone (GalLDH) involving ascorbate biosynthesis and higher dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) activities used to recycle ascorbate. Exogenous feeding of ascorbate synthesis precursors demonstrated that the peel had stronger capability of de novo ascorbate biosynthesis via Smirnoff-Wheeler pathway and uronic acid pathway whereas the flesh and core had lower capability for ascorbate synthesis. These results suggest that the pear fruit is able to cause de novo ascorbate biosynthesis and the peel had higher capability for ascorbate biosynthesis than the flesh and core.Keywords: Pyrus pyrifolia, ascorbate, biosynthesisAfrican Journal of Biotechnology Vol. 12(16), pp. 1952-196