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Ultrafast high‐temperature sintering (UHS) is a joule heating method with an extremely high heating rate (∼103–104°C/min). In this work, commercial ZrB2 powders were rapidly densified by UHS to >90% relative density within 60 s in vacuum without pressure. Bulk density improved from 75% to 93% of relative density by increasing the sintering duration from 10 to 60 s. The final grain size increases from 2.7 ± 1.1 to 19.0 ± 8.4 μm when the sintering time increased from 10 to 60 s. X‐ray diffraction and energy‐dispersive spectroscopy show crystalline phase and compositional uniformity in ZrB2 after UHS. [ABSTRACT FROM AUTHOR]

The black hole X-ray binary GX 339-4 showed an X-ray outburst during 2021. The AstroSat captured this outburst when the source entered into the intermediate flux state while the count rate was declining. The source showed an alternating flux profile in a time-scale of ≲100 ks, where the hard energy band was more variable than the soft band. The energy-dependent timing study showed that the observed quasi-periodic oscillation (QPO) was prominent in the low-energy bands, with its nearly sub-harmonic and harmonic components. These components appear and disappear with time, as observed in the orbit-wise QPO study. The Q-value, fractional rms, and 4.8–5.6 Hz frequency infer the QPOs as type-B and the spectral state as soft intermediate. The rms spectra of all orbits exhibiting QPOs show an increase in amplitude till ∼10 keV, beyond which it starts decreasing. This may indicate that ∼10 keV photons contributed relatively more in QPOs than other energy band photons. The Lorentzian normalization of the type-B QPO in different energy bands is consistent with the 10 keV peak. The energy-dependent time lag is complex and could be associated with the Comptonizing corona or jet. Finally, we discuss possible reasons behind the origin of different timing properties observed. [ABSTRACT FROM AUTHOR]

Background: Many studies have showed that adenosine deaminase (ADA) and alkaline phosphatase (ALP) values were highly supportive in the diagnosis of tuberculosis but comparison between ADA and ALP has not been much documented in pleural fluid (PF) in eastern India. Hence, the main aim of the study was to identify the relation between ADA and ALP in diagnosis of tuberculosis if any. Aims and Objectives: This study was conducted to estimate and compare the levels of ADA and ALP of PF in tubercular and non-tubercular diseases. Materials and Methods: This study was hospital-based, cross-sectional, and observational study during the period of 1 year. A total of 90 patients have been analyzed among them after excluding few outliers, 82 patients had been taken whose ADA and ALP were measured in PFs. Results: Kolmogorov–Smirnov and Shapiro–Wilk tests for statistical analysis were used to determine whether continuous variables were normally distributed or not. In the comparison of tubercular and non-tubercular effusion groups, P-value for ADA in independent t-test was 0.000, and P-value for ADA and ALP in Mann–Whitney U-test was 0.000 and 0.000, respectively. Receiver operating characteristic (ROC) curve showed area under the curve (AUC) of 0.965 and 0.751 in ADA and ALP for diagnosing tuberculosis. Cutoff values of 31.87 IU/L for ADA were determined by ROC curve analysis with 100% of sensitivity and 82.3% of specificity and cutoff values of 40.5 IU/L for ALP were also determined by ROC curve analysis with 75.6% of sensitivity and 68.3% of specificity for diagnosis of tuberculosis. Conclusion: Although ADA is the best parameter for diagnosing tubercular pleural effusions, analysis of ALP is cost-effective. [ABSTRACT FROM AUTHOR]

One of the leading explanations for the origin of Fermi Bubbles is past jet activity in the Galactic center supermassive black hole Sgr A*. The claimed jets are often assumed to be perpendicular to the Galactic plane. Motivated by the orientation of pc-scale nuclear stellar disk and gas streams, as well as a low inclination of the accretion disk around Sgr A* inferred by the Event Horizon Telescope, we perform hydrodynamical simulations of nuclear jets significantly tilted relative to the Galactic rotation axis. The observed axisymmetry and hemisymmetry (north–south symmetry) of Fermi/eROSITA bubbles (FEBs) due to quasi-steady jets in Sgr A* could be produced if the jet had a super-Eddington power (≳5 × 1044 erg s−1) for a short time (jet active period ≲6 kyr) for a reasonable jet opening angle (≲10°). Such powerful explosions are, however, incompatible with the observed O viii /O vii line ratio toward the bubbles, even after considering electron–proton temperature nonequilibrium. We argue that the only remaining options for producing FEBs are (i) a low-luminosity (≈1040.5–41 erg s−1) magnetically dominated jet or accretion wind from the Sgr A*, or (ii) a supernovae or tidal disruption event driven wind of a similar luminosity from the Galactic center. [ABSTRACT FROM AUTHOR]

We present the X-ray spectral and temporal analysis of the black hole X-ray transient Swift  J1658.2–4242 observed by AstroSat. Three epochs of data have been analysed using the JeTCAF model to estimate the mass accretion rates and to understand the geometry of the flow. The best-fitting disc mass accretion rate (⁠|$\dot{m}_{\rm d}$|⁠) varies between |$0.90^{+0.02}_{-0.01}$| and |$1.09^{+0.04}_{-0.03}$| |$\dot{M}_{\rm Edd}$| in these observations, while the halo mass accretion rate changes from |$0.15^{+0.01}_{-0.01}$| to |$0.25^{+0.02}_{-0.01}$| |$\dot{M}_{\rm Edd}$|⁠. We estimate the size of the dynamic corona that varies substantially from |$64.9^{+3.9}_{-3.1}$| to |$34.5^{+2.0}_{-1.5}$|   r g and a moderately high jet/outflow collimation factor stipulates isotropic outflow. The inferred high disc mass accretion rate and bigger corona size indicate that the source might be in the intermediate to soft spectral state of black hole X-ray binaries. The mass of the black hole estimated from different model combinations is ∼14 M⊙. In addition, we compute the quasi-periodic oscillation (QPO) frequencies from the model-fitted parameters, which match the observed QPOs. We further calculate the binary parameters of the system from the decay profile of the light curve and the spectral parameters. The estimated orbital period of the system is 4.0 ± 0.4 h by assuming the companion as a mid or late K-type star. Our analysis using the JeTCAF model sheds light on the physical origin of the spectrotemporal behaviour of the source, and the observed properties are mainly due to the change in both the mass accretion rates and absorbing column density. [ABSTRACT FROM AUTHOR]

NGC 1313 X-1 is a mysterious ultraluminous X-ray (ULX) source whose X-ray-powering mechanism and bubble-like structure surrounding the source are topics of intense study. Here, we perform an X-ray spectroscopic study of the source using joint XMM-Newton and NuSTAR observations taken during 2012–2017. The combined spectra cover the energy band 0.3–20 keV. We use the accretion–ejection-based JeTCAF model for spectral analysis. The model-fitted disk mass accretion rate varies from 4.6 to 9.6 M ̇ Edd and the halo mass accretion rate varies from 4.0 to 6.1 M ̇ Edd with a dynamic Comptonizing corona of average size of ∼15 r g . The data fitting is carried out for different black hole (BH) mass values. The goodness of the fit and uncertainties in model parameters improve while using higher BH masses, with the most probable mass of the compact object being 133 ± 33 M ⊙. We have estimated the mass outflow rate, its velocity and power, and the age of the inflated bubble surrounding the source. Our estimated bubble morphology is in accordance with the observed optical bubble and winds found through high-resolution X-ray spectroscopy, suggesting that the bubble was expanded by the outflows originating from the central source. Finally, we conclude that the super-Eddington accretion onto a nearly intermediate-mass BH may power a ULX when the accretion efficiency is low, though their efficiency increases when the jet/outflow is taken into account, in agreement with numerical simulations in the literature. [ABSTRACT FROM AUTHOR]

We study the spectral properties and accretion flow behavior of an ultraluminous X-ray source M82 X-1 using NuSTAR observations. We use the physical two-component advective flow (TCAF) model to fit the data and to derive the accretion flow properties of the source. From the model fitted parameters, we found that M82 X-1 is harboring an intermediate mass black hole at its centre, where the mass varies from 156. 04 - 15.30 + 13.51 to 380. 96 - 29.76 + 28.38 M ⊙ . The error weighed average mass of the black hole is 273 ± 43 M ⊙ , which accreted in nearly super-Eddington rate. The Compton cloud was compact with a size of ∼ 13 r g and the shock compression ratio had nearly intermediate values except for the epoch four. These indicate a possible significant mass outflow from the inner region of the disk. The quasi periodic oscillation (QPO) frequencies estimated from the model fitted parameters can reproduce the observed QPOs. The robustness of the model parameters is verified by drawing the confidence contours among them. [ABSTRACT FROM AUTHOR]

The bipolar, non-thermal, high-latitude lobes known as the Fermi bubbles (FBs) are thought to originate from a massive energy release near the Galactic Centre (GC). We constrain the FB engine and the circumgalactic medium (CGM) by analytically and numerically modelling the FB edges as strong forward shocks, as inferred from recent observations. A non-directed energy release produces shocks too spherical to account for observations even for a maximally massive Galactic disc, critical CGM rotation, or injection effectively offset from the GC. In contrast, collimated injection nearly perpendicular to the disc can account for observations in both ballistic (free expansion) and slowdown regimes, as we show using a simple stratified evolution model verified by hydrodynamic simulations. FBs still in their ballistic regime require injection (at z ≃ 100 pc heights in our model) with a half-opening angle θ ≃ 4°, a normalized velocity β −2 ≡ v /(0.01 c) ≳ 0.4, and an energy |$E\gtrsim 2\beta _{-2}^2\times 10^{55}$|  erg, launched |$\mathbb {T}\simeq 3.3\beta _{-2}^{-1}$|  Myr ago, showing a distinctive low-pressure region behind the bubble head. Slowing-down (mass accumulated) FBs require a faster injection, a thinner jet, a smaller E /(β −2 θ)2, and a comparable |$\mathbb {T}$|⁠ , and follow a ballistic stage that must reach a height zs ≳ 5 kpc. [ABSTRACT FROM AUTHOR]

Low-frequency quasi-periodic oscillations (LFQPOs) have been routinely observed in black hole X-ray binaries (BHXRBs). These LFQPOs can be explained by axisymmetric shock oscillation in accretion flow around a rotating black hole. We address the physical origin of Type-C LFQPOs in BHXRBs observed by the Rossi X-ray Timing Explorer satellite considering a minimum number of free parameters, namely, specific energy and specific angular momentum of the infalling matter for a given set of BH mass and spin parameter. We apply the solution for a large number of BH candidates to further strengthen the scenario of an anticorrelation between the QPO frequency and the location of the shock. Our study also confirms that Compton cooling can be sufficient to explain the observed QPOs. [ABSTRACT FROM AUTHOR]

Selective synthesis of three different bioactive heterocycles; isoxazolines, 5‐hydroxy‐2‐isoxazolines and isoxazoles from the same starting material using TEMPO (2,2,6,6‐Tetramethylpiperidin‐1‐oxyl) as a radical initiator is reported. Selectivity was achieved using different oxidants with TEMPO. The reaction goes through a 1,5‐HAT (hydrogen atom transfer) process resulting in products with good yields. This strategy offers a straightforward route to three different heterocycles from oximes via radical‐mediated C(sp3)‐H oxidation. [ABSTRACT FROM AUTHOR]

The structural properties and radial distributions of the valence electron in different excited levels of Na atom (n = 3–5, l = 0–4; n and l being the principal and orbital angular momentum quantum numbers, respectively) under impenetrable spherical confinement have been studied, where the interaction between the frozen core and the valence electron is mimicked by a model potential available in the literature. The effect of the core on the valence electron has been investigated by estimating the structural properties of Na10+ ion under similar confinement. Scaled radial densities at the nucleus and related ratios are presented for a few excited states of the valence electron of Na atom and the corresponding analytic results have been tested numerically. [ABSTRACT FROM AUTHOR]

Citrullination is a post-translational modification (PTM) that converts peptidyl-arginine into peptidyl-citrulline; citrullination is catalyzed by the protein arginine deiminases (PADs). This PTM is associated with several physiological processes, including the epigenetic regulation of gene expression, neutrophil extracellular trap formation, and DNA-damage induced apoptosis. Notably, aberrant protein citrullination is relevant to several autoimmune and neurodegenerative diseases and certain forms of cancer. As such, the PADs are promising therapeutic targets. In this review, we discuss recent advances in the development of PAD inhibitors and activity-based probes, the development and use of citrulline-specific probes in chemoproteomic applications, and methods to site-specifically incorporate citrulline into proteins. [ABSTRACT FROM AUTHOR]

X-ray flux from the inner hot region around central compact object in a binary system illuminates the upper surface of an accretion disc and it behaves like a corona. This region can be photoionized by the illuminating radiation, and thus can emit different emission lines. We study those line spectra in black hole X-ray binaries for different accretion flow parameters including its geometry. The varying range of model parameters captures maximum possible observational features. We also put light on the routinely observed Fe-line emission properties based on different model parameters, ionization rate, and Fe abundances. We find that the Fe-line equivalent width W E decreases with increasing disc accretion rate and increases with the column density of the illuminated gas. Our estimated line properties are in agreement with observational signatures. [ABSTRACT FROM AUTHOR]

Atomic systems placed in external potentials manifest various characteristic features which provide useful knowledge about the surroundings. We have studied the structural properties of the ground state of different two-electron systems under isotropic harmonic confinement (IHC). In particular, we have considered negative hydrogen ion, neutral helium atom and positive singly ionized lithium ion to cover all types of charge states. In addition, we have also studied the system of two electrons inside IHC. The wave function is expanded in Hylleraas basis to incorporate the effect of electron correlation in an explicit manner and Ritz variational calculations are performed to obtain the energy eigenvalues and the relative wave functions. The energy levels become more positive with increasing strength of the confining potential. The results show that for ionic systems, the two-electron energy level crosses the respective one-electron threshold at a certain value of the potential beyond which the two-electron level becomes quasi-bound. In order to get deeper insight into such threshold ionization phenomenon, we have examined the contribution of the correlated energy E corr [sum of radial and angular correlation energy] and radial correlation energy E rad. corr to the total energy for different two-electron systems under IHC. The Hellmann–Feynman theorem and the virial theorem have been verified as a quantitative validation of the accuracy of our results. The one- and two-electron radial densities have also been analyzed to gain a physical insight into the structural changes of the two-electron systems under IHC. Moreover, the expectation values of different radial and angular variables are also reported which are important to estimate different geometrical and spectral properties. [ABSTRACT FROM AUTHOR]

Structural properties of 1s2nl (2L) [n = 2–5, l = 0–4; where, n and l are the principal quantum number and orbital angular momentum quantum number, respectively] states of Li atom embedded in classical weakly coupled plasma (WCP) and dense quantum plasma (DQP) have been discussed. The Debye‐Hu¨ckel potential or the screened‐Coulomb potential (SCP) and exponential‐cosine‐screened Coulomb potential (ECSCP) have been used to mimic the WCP and DQP, respectively. Li atom has been treated as a composite system with a frozen core Li+ ion and a chemically active valence electron. The Rayleigh‐Ritz variational method with Hylleraas‐type basis set has been used to estimate the energy eigenvalue of 1s2 (1S) state of Li+ ion core and a pure exponential basis has been considered to compute the energy of nl (2L) states of the valence electron of Li atom. The influence of ECSCP and SCP on the radial probability distribution of the valence electron of the Li atom has also been studied. [ABSTRACT FROM AUTHOR]

A third-order dual-polarized elliptic wide passband Frequency Selective Surface (FSS) has been proposed in this article. The unit cell is comprised of Y-shaped fractal geometry integration on the tri-pole and evolved as the stub-loaded tri-pole (SLTP) structure on an ultra-thin FR-4 substrate (ϵr = 4.4). The novel back-to-back cascading approach of the aforesaid proposed design array with optimized air spacer enhances electromagnetic coupling, resulting in maximally flat and substantially wider third-order bandpass filtering capability. −3 dB passband filtering performance (8.3–20.1 GHz) and −1 dB transmission characteristics (8.9–19.8 GHz) encompass the X and Ku band spectral ranges. The elliptical transmission coefficient leads to a remarkable passband selectivity factor (SF = 0.91). Equivalent circuit models (ECM) have been mapped, and the prototype has been experimentally validated. Angular stability (θ ≤ 40°) for both TE and TM polarizations ensures the employability of the proposed FSS for the radome. [ABSTRACT FROM AUTHOR]

A detailed analysis of the systematic uncertainties in the calculation of the isovector momentum fraction, 〈x〉u − d, helicity moment, 〈x〉Δu − Δd, and the transversity moment, 〈x〉δu − δd, of the nucleon is presented using high-statistics data on seven ensembles of gauge configurations generated by the JLab/W&M/LANL/MIT collaborations using 2 + 1-flavors of dynamical Wilson-clover quarks. The much higher statistics have facilitated better control over all systematics compared to previous lattice calculations. The least understood systematic — excited-state contamination — is quantified by studying the variation of the results as a function of different estimates of the mass gap of the first excited state, obtained from two- and three-point correlation functions, and as a function of the pion mass Mπ. The final results are obtained using a simultaneous fit in the lattice spacing a, pion mass Mπ and the finite volume parameter MπL keeping leading order corrections. The data show no significant dependence on the lattice spacing and some evidence for finite-volume corrections. Our final results, in the MS ¯ scheme at 2 GeV, are 〈x〉u − d = 0.155(17)(20), 〈x〉Δu − Δd = 0.183(14)(20) and 〈x〉δu − δd = 0.220(18)(20), where the first error is the overall analysis uncertainty assuming excited-state contributions have been removed, and the second is an additional systematic uncertainty due to possible residual excited-state contributions. These results are consistent with phenomenological global fit values. [ABSTRACT FROM AUTHOR]

(Hf 1-x Zr x)B 2 solid solution powders were synthesized by two methods. First, solution-based processing of HfCl 4 , ZrCl 4 , sucrose, and H 3 BO 3 was conducted followed by heat treatment in Argon to carry out the carbothermal reduction (CTR) reaction to form the diboride powders. Alternatively, in the so-called borohydride reduction (BHR) method, HfCl 4 , ZrCl 4 and NaBH 4 were mixed in an Argon glove box followed by heat treatment in Argon at 700−1500 °C. The synthesized powders were characterized by XRD, SEM, TEM, EDS, and TGA, and the influence of different parameters such as starting composition, heat treatment temperature and time on products characteristics were revealed. Both CTR and BHR solid solution powders were then consolidated within ∼5 min in a homemade flash sintering (FS) setup. The composition, microstructure, hardness, and thermal-oxidation properties of flash sintered ceramics were characterized, and the implication of this study and directions for future research were discussed. [ABSTRACT FROM AUTHOR]

This paper presents a photovoltaic (PV) panel fed sensorless Brushless DC motor (BLDC) drive using Sheppard –Taylor (S–T) converter for load matching in order to make the system energy efficient. In this work, a detailed study on S–T converter is done as it helps to stabilize the fluctuating output voltage of standard PV panel. Hence, in this application model, we have considered S–T converter as a feed to the six switch three phase Brushless DC (BLDC) motor drive in which the rotor position is estimated using back electromotive force (EMF) detection technique. This work is developed and studied on MATLAB/Simulink platform as well as in real time implemented hardware. The simulation model has borrowed the motor parameters (viz. stator back-EMF, rotor RPM and max. output torque, etc.) and circuit components from the implemented hardware. Finally, a detailed study of the implemented S–T converter reveals a significant performance improvement over a conventional Buck–Boost converter for same PV panel. The output results show that the scheme described in this scope of work efficiently handles the DC power generated by solar cell using S–T converter as the rotor RPM offset is negligible in closed loop motor drive. [ABSTRACT FROM AUTHOR]

In this research, near fully dense single phase bulk multicomponent transition metal nitride (Nb1/3Ta1/3Ti1/3)N1−δ has been successfully synthesized from mixed commercial powders of NbN, TaN and TiN via reaction flash sintering technique. This was performed with an applied pressure of ~ 35 MPa at 25°C under a constant DC electric field (~24‐32 V/cm). The flash event, which is the abrupt increase in current (up to ~ 25.2 A/mm2) and temperature, occurred without preheating. The threshold power dissipation on the sample right before the flash is ~ 0.7 W/mm3. The formation of single phase (Nb1/3Ta1/3Ti1/3)N1−δ random solid solution and its compositional uniformity were confirmed by XRD and EDS, respectively. The effects of ball milling duration and limiting current density on phase formation were studied. Simulation based on Joule heating provides an estimate of the ultimate sample temperature of ~ 1850°C. Vickers hardness of the obtained (Nb1/3Ta1/3Ti1/3)N1−δ is 17.6 ± 0.6 GPa, which is comparable to similarly flash sintered ingredient binary nitrides of TaN and NbN. TGA in air shows that the oxidation resistance of (Nb1/3Ta1/3Ti1/3)N1−δ is better than that of TaN and NbN but inferior to TiN. The study demonstrates that reaction flash sintering can be a highly efficient technique for synthesizing bulk multicomponent ceramics for both material fundamental investigations and application development. [ABSTRACT FROM AUTHOR]

Quasi-periodic oscillation (QPO), particularly of low frequency (LF), is a very obvious feature of outbursting black hole candidates. The association of QPOs in a specific spectral state and their transition with states make them a key ingredient in understanding the underlying physical processes that produce them. Observations have revealed that generally, in the hard spectral state of the outburst, the size of the Compton cloud is relatively bigger, which produces low-frequency QPOs (LFQPOs). In progressive days increased cooling shrinks the area of the cloud, the inner edge of the disc comes close to the black holes, and produces higher frequency QPOs. However, rotating black holes with higher spin values are likely to produce LFQPOs even if their inner edge of the disc is closer to the hole. Here, for the first time, we address the issue, solving hydrodynamic flow equations in the presence of qualitative turbulent pressure and cooling in pseudo-Kerr geometry. Increasing turbulence slackens the infalling flow, thus the infall time becomes longer, producing LFQPOs. Our study discovers that the effect of turbulence modifies LFQPOs value significantly, by a factor of a few lower throughout the angular momentum distribution of the flow. We find a strong correlation between the turbulence and the spin parameter of the hole. Finally, we discuss the observed results in light of the present solution. [ABSTRACT FROM AUTHOR]

We study the central mass accretion rate and its variation with time during the outburst of X-ray transients using disk irradiation effect once the outer boundary of the disk is defined by the binary parameters. We show that the decay of the light curve and its characteristics time are well linked to the disk aspect ratio (H / R) and the binary parameters. For that we parametrize viscosity (α) parameter with H / R , assuming that there is a vertical height dependence on the energy dissipated in the disk. We derive the central accretion rate to check the sensitivity on H / R. Mass accretion rate changes notably with disk height, orbital period (P) and with binary mass function (q). For the consistency check, we apply the solution to a low mass X-ray binary (LMXRB) 4U 1543-47, whose binary parameters are dynamically measured. Finally, we estimate the unknown binary parameters of MAXI J1543-564. Using this solution for the first time we propose some predictability on P for the unknown system. The estimated value of P varies in a range from ∼10.5 to 15.5 h, when the companion mass is ∼ 0.66 M ⊙ . Our estimated decay time scale is ∼ 40 d with α ∼ 0.18. [ABSTRACT FROM AUTHOR]

Protein arginine deiminases (PADs) hydrolyze the side chain of arginine to form citrulline. Aberrant PAD activity is associated with rheumatoid arthritis, multiple sclerosis, lupus, and certain cancers. These pathologies established the PADs as therapeutic targets and multiple PAD inhibitors are known. Herein, we describe the first highly potent PAD1‐selective inhibitors (1 and 19). Detailed structure–activity relationships indicate that their potency and selectivity is due to the formation of a halogen bond with PAD1. Importantly, these inhibitors inhibit histone H3 citrullination in HEK293TPAD1 cells and mouse zygotes with excellent potency. Based on this scaffold, we also developed a PAD1‐selective activity‐based probe that shows remarkable cellular efficacy and proteome selectivity. Based on their potency and selectivity we expect that 1 and 19 will be widely used chemical tools to understand PAD1 biology. [ABSTRACT FROM AUTHOR]

Protein arginine deiminases (PADs) hydrolyze the side chain of arginine to form citrulline. Aberrant PAD activity is associated with rheumatoid arthritis, multiple sclerosis, lupus, and certain cancers. These pathologies established the PADs as therapeutic targets and multiple PAD inhibitors are known. Herein, we describe the first highly potent PAD1‐selective inhibitors (1 and 19). Detailed structure–activity relationships indicate that their potency and selectivity is due to the formation of a halogen bond with PAD1. Importantly, these inhibitors inhibit histone H3 citrullination in HEK293TPAD1 cells and mouse zygotes with excellent potency. Based on this scaffold, we also developed a PAD1‐selective activity‐based probe that shows remarkable cellular efficacy and proteome selectivity. Based on their potency and selectivity we expect that 1 and 19 will be widely used chemical tools to understand PAD1 biology. [ABSTRACT FROM AUTHOR]

In this paper a compact patch antenna backed with artificial meta-surface known as reactive impedance surface (RIS) is designed for circular polarization in the ISM band. The antenna consists of an asymmetric diagonal slits with pair of complementary split ring resonators (CSRRs) on patch over the RIS structure. Asymmetric slits and pair of CSRRs are inserted on radiating patch to achieve circular polarization. RIS is used for improving the radiation characteristics of the antenna, while RIS-based patch provides good impedance matching over a broad frequency range. Simulated results are in good agreement with the measured results. [ABSTRACT FROM AUTHOR]

We report a detailed spectral study of the Swift J1357.2–0933 low-mass X-ray binary during its 2017 outburst using Swift and NuSTAR observations. We fit the data with a two-component advective flow (TCAF) model and a power-law model. We observe that the source is in a hard state during the outburst, where the size of the Compton cloud changes significantly with disc accretion rate. The typical disc accretion rate for this source is |${\sim } 1.5\hbox{--}2.0\,{{\ \rm per\ cent}}$| of the Eddington accretion rate |$(\skew2\dot{M}_\mathrm{Edd})$|⁠. The model-fitted intermediate shock compression ratio gives an indication of the presence of a jet, which is reported in the literature in different energy bands. We also split the NuSTAR data into three equal segments and fit them with the model. We check spectral stability using a colour–colour diagram and an accretion rate ratio (ARR) versus intensity diagram using different segments of the light curve, but do not find any significant variation in the hardness ratio or in the accretion rate ratio. To estimate the mass of the candidate, we use an important characteristic of TCAF that the the model normalization always remains a constant. We found that the mass comes out to be in the range of 4.0–6.8 M⊙. From the model-fitted results, we study the disc geometry and different physical parameters of the flow in each observation. The count rate of the source appears to decay on a time-scale of |${\sim } 45\, \mathrm{d}$|⁠. [ABSTRACT FROM AUTHOR]

Halogenated nucleosides, such as 5‐iodo‐2′‐deoxyuridine and 5‐iodo‐2′‐deoxycytidine, are incorporated into the DNA of replicating cells to facilitate DNA single‐strand breaks and intra‐ or interstrand crosslinks upon UV irradiation. In this work, it is shown that the naphthyl‐based organoselenium compounds can mediate the dehalogenation of halogenated pyrimidine‐based nucleosides, such as 5‐X‐2′‐deoxyuridine and 5‐X‐2′‐deoxycytidine (X=Br or I). The rate of deiodination was found to be significantly higher than that of the debromination for both nucleosides. Furthermore, the deiodination of iodo‐cytidines was found to be faster than that of iodo‐uridines. The initial rates of the deiodinations of 5‐iodocytosine and 5‐iodouracil indicated that the nature of the sugar moiety influences the kinetics of the deiodination. For both the nucleobases and nucleosides, the deiodination and debromination reactions follow a halogen‐bond‐mediated and addition/elimination pathway, respectively. DNA photosensitizers: Dehalogenation of halogenated nucleosides, which are potential DNA photosensitizers, by organoselenium compounds is described (see picture). Attachment of 2′‐deoxyribose or ribose sugar to the halogenated nucleobases significantly enhances the rate of deiodination reactions. The Se⋅⋅⋅I halogen bonding plays an important role in the kinetics of the deiodination reactions. [ABSTRACT FROM AUTHOR]

For a finite abelian group (G , +) , the constant C (G) is defined to be the smallest natural number k such that any sequence in G having length k will have a subsequence of consecutive terms whose sum is zero. For a subset A of Z n , the constant C A (n) is the smallest natural number k such that any sequence in G having length k will have an A -weighted zero-sum subsequence of consecutive terms. We determine the value of C A (n) for some weight-sets A which are related to units in Z n. [ABSTRACT FROM AUTHOR]

In this paper, a shorted planar elliptical metal antenna (SPEMA) is designed for ultra-wideband (UWB) applications. The shorting strip yields almost 20% size reduction and the impedance bandwidth for S11 < -10 dB of the SPEMA covers the entire UWB (3.1-10.6 GHz). The surface current distribution of the proposed antenna is observed. Two symmetrical antennas are placed very closely for multiple-input multiple-output (MIMO) applications. The proposed MIMO antenna exhibits low reflection coefficient (< -10 dB), low mutual coupling (< -13 dB), and low correlation coefficient (<0.02) in UWB range. The absolute peak gain and radiation patterns in E and H plane of the MIMO antenna are presented. Measured results are in good agreement with the simulated results. [ABSTRACT FROM AUTHOR]

Abstract: Over the recent decade tremendous interest has been developed on the synthetic modification of natural as well as non‐proteinogenic amino acids and non‐natural linkages due to their immensely important applications in proteomics, diagnosis, and drug delivery etc. They are synthetically important also. For example, due to the high natural abundance of enantiopure amino acids, they and their derivatives are regularly employed in the development of several interesting synthetic methods, total syntheses of biologically related structures as well as in ligand elaboration. Thus, the synthetic field possesses a direct impact on several basic and applied sciences. But up to date only limited numbers of reviews are available which either appeared almost half a decade earlier or covered very specific areas of this highly expanding topic. Many achievements have already been realized in this field in the meantime which urgently need to be documented. Therefore, to meet the need this review is intended to cover the emerging versatile synthetic methods on the modification of amino acids and related structures over the recent decade with the relevant details of their respective prospects and problems in the best possible systematic and concise manner. Wherever needed relevant mechanistic details are also described. [ABSTRACT FROM AUTHOR]

To aid development of cost-effective sintered spinel as a refractory raw material, this paper presents an extensive analysis of microstructure and complex phase evolution of Al-rich, Mg-rich, and stoichiometric spinel aggregates derived from Indian magnesite and calcined alumina. Pore morphology in Al-rich spinel was transformed upon sintering at 1650°C and corundum laths embedded in porous Al-rich spinel matrix was formed. Stoichiometric spinel sintered at 1600°C consisted of mostly direct bonded angular equiaxed spinel grains which incorporated the impurities in solid solution. Mg-rich spinel was composed of spinel grains with reduced angularity along with intergranular amorphous phase, small round monticellite grains, and periclase. EDS line scan revealed impurity-free joins existed between direct bonded spinel grains. Mg-rich spinel containing 0.65 wt% ZrO2 formed cubic ZrO2-CaO-MgO solid solution located along spinel boundaries, which reduced both intergranular amorphous phase and monticellite. This increased SiO2 and MgO content in spinel solid solution triggering exsolution of metastable cubic forsterite manifested as split spinel peaks in XRD pattern. A 14.7% reduction in slag penetration was exhibited upon doping Mg-rich spinel with 0.21% ZrO2. Stoichiometric and Mg-rich spinels attained 0.35% and 0.54% apparent porosity at 1600°C, which is better than most commercial sintered refractory spinels. [ABSTRACT FROM AUTHOR]

Thyroid hormones (THs) play key roles in modulating the overall metabolism of the body, protein synthesis, fat metabolism, neuronal and bone growth, and cardiovascular as well as renal functions. In this review, we discuss on the thyroid hormone synthesis and activation, thyroid hormone receptors (TRs) and mechanism of action, applications of thyroid hormone analogues, particularly the compounds that are selective ligands for TRβ receptors, or enzyme inhibitors for the treatment of thyroidal disorders with a specific focus on thyroid peroxidase and iodothyronine deiodinases. We also discuss on the development of small-molecule deiodinase mimetics and their mechanism of deiodination, as these compounds have the potential to regulate the thyroid hormone levels. [ABSTRACT FROM AUTHOR]

Iodothyronamines (TAMs) are endogenous thyroid hormone (TH) metabolites, which are proposed to be biosynthesized by decarboxylation of the β-alanine side chain of THs. Iodothyronine deiodinases (DIOs) mediate phenolic and tyrosyl ring deiodinations of thyroid hormones and play an important role in thyroid hormone homeostasis. These enzymes also accept iodothyronamines as substrates for deiodination, but the binding affinities of TAMs to DIOs are lower than that of THs. In this paper, we report, for the first time, the formation of halogen bonding in various iodothyronamines by using single crystal X-ray studies. We also describe the conformational changes that take place in the structures of THs and TAMs upon deiodination. Density functional theory calculations were performed to understand the halogen bonded assembly and their biological implications. [ABSTRACT FROM AUTHOR]

Thyroid hormones (THs) are secreted by the thyroid gland. They control lipid, carbohydrate, and protein metabolism, heart rate, neural development, as well as cardiovascular, renal, and brain functions. The thyroid gland mainly produces l-thyroxine (T4) as a prohormone, and 5′-deiodination of T4 by iodothyronine deiodinases generates the nuclear receptor binding hormone T3. In this Review, we discuss the basic aspects of the chemistry and biology as well as recent advances in the biosynthesis of THs in the thyroid gland, plasma transport, and internalization of THs in their target organs, in addition to the deiodination and various other enzyme-mediated metabolic pathways of THs. We also discuss thyroid hormone receptors and their mechanism of action to regulate gene expression, as well as various thyroid-related disorders and the available treatments. [ABSTRACT FROM AUTHOR]

Schilddrüsenhormone (THs) werden von der Schilddrüse abgegeben. Sie kontrollieren Fett‐, Kohlenhydrat‐ und Proteinmetabolismus, Herzfrequenz, neuronale Entwicklung sowie kardiovaskuläre, renale und neuronale Funktionen. Die Schilddrüse produziert überwiegend l‐Thyroxin (T4), das als Prohormon fungiert. Durch 5′‐Deiodierung, katalysiert von Iodthyronin‐Deiodasen, wird aktives T3 gebildet, das an den nukleären Schilddrüsenhormon‐Rezeptor bindet. In diesem Aufsatz fassen wir sowohl die grundlegende Chemie und Biologie als auch die neuesten Erkenntnisse zur TH‐Biosynthese, zum Plasmatransport und zur Internalisierung der THs in die Zielorgane, zur Deiodierung und zu einer Vielzahl anderer Enzym‐vermittelter Stoffwechselwege zusammen. Zudem erörtern wir Schilddrüsenhormon‐Rezeptoren, verschiedene Schilddrüsen‐bedingte Krankheiten und deren Therapien. Die Hormone der Schilddrüse sind entscheidend für die Regulation des Energiestoffwechsels, der Herzfrequenz, der Entwicklung des Nervensystems sowie der Funktion von Kreislauf, Niere und Gehirn. Dieser Aufsatz diskutiert die Chemie und Biologie der Biosynthese, des Stoffwechsels und der Wirkung von Schilddrüsenhormonen vor dem Hintergrund von Schilddrüsenerkrankungen und ihrer Therapie. [ABSTRACT FROM AUTHOR]

It has long been proposed that low-frequency quasi-periodic oscillations (QPOs) in stellar-mass black holes or their equivalents in supermassive black holes are the result of resonances between infall and cooling timescales. We explicitly compute these two timescales in a generic situation to show that resonances are easily achieved. During an outburst of a transient black hole candidate, the accretion rate of the Keplerian disc as well as the geometry of the Comptonizing cloud change very rapidly. During some period, a resonance condition between the cooling timescale (predominantly by Comptonization) and the infall timescale of the Comptonizing cloud is roughly satisfied. This leads to low-frequency quasi-periodic oscillations (LFQPOs) of the Compton cloud and the consequent oscillation of hard X-rays. In this paper, we explicitly follow black hole candidate H1743-322 during its 2010 outburst. We compute the Compton cooling time and infall time over several days and show that QPOs take place when these two roughly agree within ~50 percent, i.e., the resonance condition is generally satisfied. We also confirm that for the sharper LFQPOs (i.e. higher Q-factors) the ratio of the two timescales is very close to 1. [ABSTRACT FROM AUTHOR]

Thyroid hormones regulate almost every process in the body, including body temperature, growth, and heart rate. They influence carbohydrate metabolism, protein synthesis and breakdown, and cardiovascular, renal, and brain function. Two new polymorphs of synthetic L-thyroxine (T4) are reported and the effect of polymorphism on the solubility of this important hormone is shown. Conformational changes were also discovered to have a remarkable effect on the strength of halogen bonding and the reactivity of the CI bonds, which could have a significant effect on the hormone activity. [ABSTRACT FROM AUTHOR]

Thyroid hormones regulate almost every process in the body, including body temperature, growth, and heart rate. They influence carbohydrate metabolism, protein synthesis and breakdown, and cardiovascular, renal, and brain function. Two new polymorphs of synthetic L-thyroxine (T4) are reported and the effect of polymorphism on the solubility of this important hormone is shown. Conformational changes were also discovered to have a remarkable effect on the strength of halogen bonding and the reactivity of the CI bonds, which could have a significant effect on the hormone activity. [ABSTRACT FROM AUTHOR]

Halogenated nucleosides can be incorporated into the newly synthesized DNA of replicating cells and therefore are commonly used in the detection of proliferating cells in living tissues. Dehalogenation of these modified nucleosides is one of the key pathways involved in DNA repair mediated by the uracil-DNA glycosylase. Herein, we report the first example of a selenium-mediated dehalogenation of halogenated nucleosides. We also show that the mechanism for the debromination is remarkably different from that of deiodination and that the presence of a ribose or deoxyribose moiety in the nucleosides facilitates the deiodination. The results described herein should help in understanding the metabolism of halogenated nucleosides in DNA and RNA. [ABSTRACT FROM AUTHOR]

ABSTRACT In this article, a planar circular metal antenna is designed for ultrawideband applications. A modified design formula is proposed to predict the lower cut off frequency of the antenna. The error between theoretical and simulated lower cut off frequency is within 5% for variation of radius of the radiating element from 3 to 9 cm. A shorting strip is connected as a top inductive load to reduce the size of the antenna. The simulated and measured reflection coefficient, gain, and radiation pattern of the proposed shorted planar circular metal antenna are in good agreement. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1925-1928, 2015 [ABSTRACT FROM AUTHOR]

We study spectral properties of GX 339-4 during its 2010-11 outburst with two component advective flow (TCAF) model after its inclusion in XSPEC as a table model.We compare results fitted by TCAF model with combined disc blackbody and power-law model. For a spectral fit, we use 2.5-25 keV spectral data of the Proportional Counter Array instrument onboard RXTE satellite. From our fit, accretion flow parameters such as Keplerian (disc) rate, sub- Keplerian (halo) rate, location and strength of shock are extracted. We quantify how the disc and the halo rates vary during the entire outburst.We study how the halo to disc accretion rate ratio (ARR), quasi-periodic oscillations (QPOs), shock locations and its strength vary when the system passes through hard, hard-intermediate, soft-intermediate and soft states. We find pieces of evidence of monotonically increasing and decreasing nature of QPO frequencies depending on the variation of ARR during rising and declining phases. Interestingly, on days of transition from hard state to hard-intermediate spectral state (during the rising phase) or vice-versa (during decline phase), ARR is observed to be locally maximum. Non-constancy of ARR while obtaining reasonable fits points to the presence of two independent components in the flow. [ABSTRACT FROM AUTHOR]

The type 1 iodothyronine deiodinase (1D-1) in liver and kidney converts the L-thyroxine ( T4), a prohormone, by outer-ring (5′) deiodination to biologically active 3,3′,5-triiodothyronine ( T3) or by inner-ring (5) deiodination to inactive 3,3′,5′-triiodothronine ( rT3). Sulfate conjugation is an important step in the irreversible inactivation of thyroid hormones. While sulfate conjugation of the phenolic hydroxyl group stimulates the 5-deiodination of T4 and T3, it blocks the 5′-deiodination of T4. We show that thyroxine sulfate ( T4S) undergoes faster deiodination as compared to the parent thyroid hormone T4 by synthetic selenium compounds. It is also shown that ID-3 mimics, which are remarkably selective to the inner-ring deiodination of T4 and T3, changes the selectivity completely when T4S is used as a substrate. From the theoretical investigations, it is observed that the strength of halogen bonding increases upon sulfate conjugation, which leads to a change in the regioselectivity of ID-3 mimics towards the deiodination of T4S. It has been shown that these mimics perform both the 5′- and 5-ring deiodinations by an identical mechanism. [ABSTRACT FROM AUTHOR]

Accretion flows having positive specific energy are known to produce outflows and winds which escape to a large distance. According to Two Component Advective Flow (TCAF) model, centrifugal pressure dominated region of the flow just outside the black hole horizon, with or without shocks, acts as the base of this outflow. Electrons from this region are depleted due to the wind and consequently, energy transfer rate due to inverse Comptonization of low energy photons are affected. Specifically, it becomes easier to cool this region and emerging spectrum is softened. Our main goal is to show spectral softening due to mass outflow in presence of Compton cooling. To achieve this, we modify Rankine-Hugoniot relationships at the shock front when post-shock region suffers mass loss due to winds and energy loss due to inverse Comptonization. We solve two-temperature equations governing an accretion flow around a black hole which include Coulomb exchange between protons and electrons and other major radiative processes such as bremsstrahlung and thermal Comptonization. We then compute emitted spectrum from this post-shock flow. We also show how location of standing shock which forms outer boundary of centrifugal barrier changes with cooling. With an increase in disc accretion rate $(\dot{m}_{d})$, cooling is enhanced and we find that the shock moves in towards the black hole. With cooling, thermal pressure is reduced, and as a result, outflow rate is decreased. We thus directly correlate outflow rate with spectral state of the disc. [ABSTRACT FROM AUTHOR]

Iodothyronine deiodinases (IDs) are mammalian selenoenzymes that play an important role in the activation and inactivation£ of thyroid hormones. It is known that iodothyronamines (TnAMs), produced by the decarboxylation of thyroid hormones, act as substrates for deiodinases. To understand whether decarboxylation alters the rate and/or regioselectivity of deiodination by using synthetic deiodinase mimics, we studied the deiodination of different iodothyronamines. The triiodo derivative 3,3′,5-triiodothyronamine (T3 AM) is deiodinated at the inner ring by naphthyl-based deiodinase mimics, which is similar to the deiodination of 3,3′,5-triiodothyronine (T3). However, T3 AM undergoes much slower deiodination than T3. Detailed experimental and theoretical investigations suggest that T3 AM forms a weaker halogen bond with selenium donors than T3. Kinetic studies and single-crystal X-ray structures of T3 and T3 AM reveal that intermolecular I⋅⋅⋅I interactions may play an important role in deiodination. The formation of hydrogen- and halogen-bonding assemblies, which leads to the formation of a dimeric species of T3 in solution, facilitates the interactions between the selenium and iodine atoms. In contrast, T3 AM, which does not have I⋅⋅⋅I interactions, undergoes much slower deiodination. [ABSTRACT FROM AUTHOR]

We study accretion flow dynamics of the Galactic transient black hole candidate (BHC) H 1743-322 during its 2010 outburst by analyzing spectral data using the two-component advective flow (TCAF; Keplerian and sub-Keplerian) solution after its inclusion in XSPEC as a local model. We compare our TCAF solution fitted results with combined disk blackbody (DBB) and power-law (PL) model fitted results and find a similar smooth variation of thermal (Keplerian or DBB) and non-thermal (PL or sub-Keplerian) fluxes/rates in two types of model fits. For a spectral analysis, 2.5-25 keV spectral data from the Rossi X-Ray Timing Explorer Proportional Counter Array instrument are used. From the TCAF solution fit, accretion flow parameters, such as Keplerian rate, sub-Keplerian rate, location of centrifugal pressure-supported shock, and strength of the shock, are extracted, providing a deeper understanding of the accretion process and properties of accretion disks around BHC H 1743-322 during its X-ray outburst. Based on the halo to disk accretion rate ratio, shock properties, accretion rates, and the nature of the quasi-periodic oscillations' (if observed) entire outburst is classified into four different spectral states: hard, hard-intermediate, soft-intermediate, and soft. From the time variation of intrinsic flow parameters, it appears that their evolutions in the declining phase do not retrace the path of the rising phase. Since our current model does not include magnetic fields, spectral turnover at energies beyond 500-600 keV cannot be explained. [ABSTRACT FROM AUTHOR]

We study self-consistently the hydrodynamic and spectral properties of a general class of steady-state accretion discs where we couple both the hydrodynamics and the radiative transfer. We consider a two-component accretion flow in which the Keplerian disc is immersed inside an accreting low angular momentum flow (halo) around a black hole. The injected soft photons from the Keplerian disc are reprocessed by the electrons in the halo. We study the transonic properties of such a Comptonized flow. We use the Rankine–Hugoniot relation to obtain the shock locations in the disc and compute the radiated spectrum from this shocked disc. We identify the boundary of the parameter space spanned by the specific energy and angular momentum which allows the formation of the standing shocks. We show how the boundary changes in the presence of Compton cooling. Due to the radiative loss, some energy is removed from the accreting matter and the shock moves towards the black hole to maintain the pressure balance condition. We solve the two-temperature equations with Coulomb energy exchange between the protons and the electrons, and the radiative processes such as the bremsstrahlung and thermal Comptonization. We study the variation of the hydrodynamical and spectral properties as a function of the accretion rates of the Keplerian and sub-Keplerian components. Ours is the most accurate transonic solution of an inviscid flow around a black hole to date. [ABSTRACT FROM AUTHOR]

A novel design of planar hexagonal antenna (PHA) fed by a coplanar waveguide has been presented for wideband applications.The semicircular base to upper and lower side of hexagonal radiator increases the impedance bandwidth. A shorting strip is introduced as a top load to the antenna to achieve compactness. The proposed shorted PHA (SPHA) yields bidirectional radiation pattern in both elevation and azimuth plane. The −10 dB return loss of SPHA exhibits from 1.24 to 20 GHz. The simulated results for various characteristics of the antenna have been shown using finite integration technique based commercial software CST MICROWAVE STUDIO. The simulated and measured return loss characteristics of SPHA are in good agreement. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1-4, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27276 [ABSTRACT FROM AUTHOR]

Bound state energy (E) and the position ( E r ) and width (Γ ) of the first S symmetry doubly excited Feshbach resonance state of various symmetrical three-body systems (XYY) bound via screened Coulomb (SC) interaction have been reported using soft-wall strategy of stabilization method. Explicitly correlated multi-exponent Hylleraas-type basis set has been considered under the Ritz variational framework. Critical nuclear charges of the systems in its ground state ( Z c ) as well as in Feshbach resonance state ( Z c ) for various screening parameters (λ ) have been evaluated. First-order quantum phase transition (QPT) for all the systems has been reported in its ground state. Effect of different mass combination of the constituents particles on critical points of the systems has been explored extensively. [ABSTRACT FROM AUTHOR]

A simple pure-exponential type wavefunction in the Ritz variational framework has been proposed to estimate precise eigenenergies and radial distributions of n l [ n = 1–8; l = 0–7] states of 2 L [ L = 0–7] symmetry of hydrogen iso-electronic ions (Z =1–18) under classical weakly coupled plasma and dense quantum plasma environment. Critical screening parameters, beyond which the ions cease to be in a bound state, have also been estimated for both types of plasma background. [ABSTRACT FROM AUTHOR]