Frequency-dependent (ac) Conduction in Disordered Composites: a Percolative Study

In a recent paper [Phys. Rev. B{\bf57}, 3375 (1998)], we examined in detail the nonlinear (electrical) dc response of a random resistor cum tunneling bond network ($RRTN$, introduced by us elsewhere to explain nonlinear response of metal-insulator type mixtures). In this work which is a sequel to that paper, we consider the ac response of the $RRTN$-based correlated $RC$ ($CRC$) model. Numerical solutions of the Kirchoff's laws for the $CRC$ model give a power-law exponent (= 0.7 near $p = p_c$) of the modulus of the complex ac conductance at moderately low frequencies, in conformity with experiments on various types of disordered systems. But, at very low frequencies, it gives a simple quadratic or linear dependence on the frequency depending upon whether the system is percolating or not. We do also discuss the effective medium approximation ($EMA$) of our $CRC$ and the traditional random $RC$ network model, and discuss their comparative successes and shortcomings.Comment: Revised and reduced version with 17 LaTeX pages plus 8 JPEG figure

Deletion of Constitutive Androstane Receptor Led to Intestinal Alterations and Increased Imidacloprid in Murine Liver

Imidacloprid (IMI) is the most frequently detected neonicotinoid pesticide in the environment. Despite typically low toxicity in vertebrates, IMI exposure is associated with liver and gastrointestinal toxicity. The mechanism underlying IMI toxicity in mammals is unclear. Pesticide exposure frequently activates xenobiotic nuclear receptors, such as the constitutive androstane receptor (CAR), to induce detoxification phase I and phase II genes. This study examined the role of CAR in mediating IMI off-target toxicity. Female Car-/- and wild-type (WT) mice were orally administered imidacloprid (50 mg/kg, twice daily) for 21 days, following which serum, liver, and intestinal tissues were collected. Liver tissue analysis indicated mild inflammation and induction of detoxification gene Cyp2b10 in IMI-exposed WT mice. The absence of CAR increased hepatic IMI accumulation. Microbiome analysis of ileal samples revealed IMI altered microbial diversity in a genotype-specific manner, with increased α-diversity in Car-/- mice while decreased α-diversity in WT mice. We observed Car-/- mice exhibit intestinal alterations with decreased CYP-P450 expression, blunted villi height, and increased small intestine length and weight independent of IMI exposure. Our results suggest that IMI is not overtly toxic. However, the absence of xenobiotic nuclear receptor CAR allows increased accumulation of IMI in the liver and disrupts the villi structure and Cyp gene expression in the intestine. © 2022 The Author(s). Published by Oxford University Press on behalf of the Endocrine Society.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

In vitro and in vivo evaluation of 2-chloroethylnitrosourea derivatives as antitumor agents

Aim: To evaluate potential of Naphthal-NU, Napro-NU and 5-Nitro-naphthal-NU, 2-chloroethylnitrosourea compounds with substituted naphthalimide in the pre-clinical studies. Materials and Methods: In vitro cytotoxicity of three nitrosoureas was determined in human and mouse tumor cell lines by MTT assays. In vivo anti-tumor potential was evaluated in Sarcoma-180 (S-180) and Ehrlich’s carcinoma (EC) solid tumors. Apoptosis in S-180 cells was analyzed by using Annexin V-Propidium Iodide (PI). Histological analysis of liver and kidney was performed at optimum dose (50 mg/kg). Expression status of CD4+, CD8+ and CD25+ cells in treated mouse were also examined. Results: Significant tumor growth retardation by the compounds was noted in early and advanced disease groups, as the life span of drug treated mice increased considerably. Drug induced killing was observed by induction of apoptosis. Naphthal-NU and 5-Nitro-naphthal-NU were effective to normalize the tumor induced structural abnormalities of liver and kidney. The compounds have no immunotoxic effect on CD4+ and CD8+ T cells and down regulate CD4+CD25+ regulatory T cells. Conclusion: Overall data holds promise for the antitumor activity with lower toxicity of the compounds that can be utilized for the treatment of human malignant tumors. Key Words: cytotoxicity, Naphthal-NU, Napro-NU, 5-Nitro-naphthal-NU, Sarcoma-180, Ehrlich’s carcinoma

Thin-shell wormholes in Einstein-Maxwell theory with a Gauss-Bonnet term

We study five dimensional thin-shell wormholes in Einstein-Maxwell theory with a Gauss-Bonnet term. The linearized stability under radial perturbations and the amount of exotic matter are analyzed as a function of the parameters of the model. We find that the inclusion of the quadratic correction substantially widens the range of possible stable configurations, and besides it allows for a reduction of the exotic matter required to construct the wormholes.Comment: 13 pages, 6 figures; v2: minor changes and new references added. Accepted for publication in General Relativity and Gravitatio

Review of experimental methods to determine spontaneous combustion susceptibility of coal – Indian context

This paper presents a critical review of the different techniques developed to investigate the susceptibility of coal to spontaneous combustion and fire. These methods may be sub-classified into the two following areas: (1) Basic coal characterisation studies (chemical constituents) and their influence on spontaneous combustion susceptibility. (2) Test methods to assess the susceptibility of a coal sample to spontaneous combustion. This is followed by a critical literature review that summarises previous research with special emphasis given to Indian coals

Searches for lepton-flavour-violating decays of the Higgs boson in s=13\sqrt{s}=13 TeV pp\mathit{pp} collisions with the ATLAS detector

This Letter presents direct searches for lepton flavour violation in Higgs boson decays, H → eτ and H → μτ , performed with the ATLAS detector at the LHC. The searches are based on a data sample of proton–proton collisions at a centre-of-mass energy √s = 13 TeV, corresponding to an integrated luminosity of 36.1 fb−1. No significant excess is observed above the expected background from Standard Model processes. The observed (median expected) 95% confidence-level upper limits on the leptonflavour-violating branching ratios are 0.47% (0.34+0.13−0.10%) and 0.28% (0.37+0.14−0.10%) for H → eτ and H → μτ , respectively.publishedVersio

Combination of searches for Higgs boson pairs in pp collisions at \sqrts = 13 TeV with the ATLAS detector

This letter presents a combination of searches for Higgs boson pair production using up to 36.1 fb(-1) of proton-proton collision data at a centre-of-mass energy root s = 13 TeV recorded with the ATLAS detector at the LHC. The combination is performed using six analyses searching for Higgs boson pairs decaying into the b (b) over barb (b) over bar, b (b) over barW(+)W(-), b (b) over bar tau(+)tau(-), W+W-W+W-, b (b) over bar gamma gamma and W+W-gamma gamma final states. Results are presented for non-resonant and resonant Higgs boson pair production modes. No statistically significant excess in data above the Standard Model predictions is found. The combined observed (expected) limit at 95% confidence level on the non-resonant Higgs boson pair production cross-section is 6.9 (10) times the predicted Standard Model cross-section. Limits are also set on the ratio (kappa(lambda)) of the Higgs boson self-coupling to its Standard Model value. This ratio is constrained at 95% confidence level in observation (expectation) to -5.0 &lt; kappa(lambda) &lt; 12.0 (-5.8 &lt; kappa(lambda) &lt; 12.0). In addition, limits are set on the production of narrow scalar resonances and spin-2 Kaluza-Klein Randall-Sundrum gravitons. Exclusion regions are also provided in the parameter space of the habemus Minimal Supersymmetric Standard Model and the Electroweak Singlet Model. For complete list of authors see http://dx.doi.org/10.1016/j.physletb.2019.135103</p

Search for flavour-changing neutral currents in processes with one top quark and a photon using 81 fb⁻¹ of pp collisions at \sqrts = 13 TeV with the ATLAS experiment

A search for flavour-changing neutral current (FCNC) events via the coupling of a top quark, a photon, and an up or charm quark is presented using 81 fb−1 of proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Events with a photon, an electron or muon, a b-tagged jet, and missing transverse momentum are selected. A neural network based on kinematic variables differentiates between events from signal and background processes. The data are consistent with the background-only hypothesis, and limits are set on the strength of the tqγ coupling in an effective field theory. These are also interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tuγ coupling of 36 fb (78 fb) and on the branching ratio for t→γu of 2.8×10−5 (6.1×10−5). In addition, they are interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tcγ coupling of 40 fb (33 fb) and on the branching ratio for t→γc of 22×10−5 (18×10−5). © 2019 The Author(s

Comparison between simulated and observed LHC beam backgrounds in the ATLAS experiment at Ebeam =4 TeV

Results of dedicated Monte Carlo simulations of beam-induced background (BIB) in the ATLAS experiment at the Large Hadron Collider (LHC) are presented and compared with data recorded in 2012. During normal physics operation this background arises mainly from scattering of the 4 TeV protons on residual gas in the beam pipe. Methods of reconstructing the BIB signals in the ATLAS detector, developed and implemented in the simulation chain based on the \textscFluka Monte Carlo simulation package, are described. The interaction rates are determined from the residual gas pressure distribution in the LHC ring in order to set an absolute scale on the predicted rates of BIB so that they can be compared quantitatively with data. Through these comparisons the origins of the BIB leading to different observables in the ATLAS detectors are analysed. The level of agreement between simulation results and BIB measurements by ATLAS in 2012 demonstrates that a good understanding of the origin of BIB has been reached