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Copyright of Journal of Medical Biochemistry is the property of Society of Medical Biochemists of Serbia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Protein S-acyl transferases (PATs) catalyze S-acylation, a reversible post-translational modification critical for membrane association, trafficking, and stability of substrate proteins. Many plant proteins are potentially S-acylated but few have corresponding PATs identified. By using genomic editing, confocal imaging, pharmacological, genetic, and biochemical assays, we demonstrate that three Arabidopsis class C PATs positively regulate BR signaling through S-acylation of BRASSINOSTEROID-SIGNALING KINASE1 (BSK1). PAT19, PAT20, and PAT22 associate with the plasma membrane (PM) and the trans-Golgi network/early endosome (TGN/EE). Functional loss of all three genes results in a plethora of defects, indicative of reduced BR signaling and rescued by enhanced BR signaling. PAT19, PAT20, and PAT22 interact with BSK1 and are critical for the S-acylation of BSK1, and for BR signaling. The PM abundance of BSK1 was reduced by functional loss of PAT19, PAT20, and PAT22 whereas abolished by its S-acylation-deficient point mutations, suggesting a key role of S-acylation in its PM targeting. Finally, an active BR analog induces vacuolar trafficking and degradation of PAT19, PAT20, or PAT22, suggesting that the S-acylation of BSK1 by the three PATs serves as a negative feedback module in BR signaling. [ABSTRACT FROM AUTHOR]

Background: Bacterial meningitis is a serious medical disorder that should be treated as soon as possible. Aim: The effect of ansamycin as a nanoformulation on Escherichia coliinduced meningitis was investigated. Materials and Methods: By injecting Escherichia coli directly into the brains of Swiss Albino mice, an experimental meningitis model was established. Results: As expected, TNF-α, IL-6, and IL-10 secretion was stimulated, following neutrophil infiltration. Additionally, the BBB's vasopermeability was raised. Ansamcyin nanoparticles were delivered to assess their therapeutic potential in preventing bacterial meningitis caused by Escherichia coli. Ansamycin nanoparticle-treated mice produced less tumour necrosis factor alpha and interleukins when brain tissue was stained, compared to nontreated mice. E. coli-induced increases in the permeability of the blood-brain barrier and infiltration of inflammatory neutrophils were also prevented. Conclusion: These findings suggest that ansamycin nanoparticles could be used to treat bacterial meningitis. It has been shown that ansamycin nanoparaticles can prevent the mice from E. coli-induced mortality, therefore enhancing their outcome. [ABSTRACT FROM AUTHOR]

In order to improve the sampling of restricted microstates in our previous work [C. Nie, J. Geng, and W. H. Marlow, J. Chem. Phys. 127, 154505 (2007); 128, 234310 (2008)] and quantitatively predict thermal properties of supersaturated vapors, an extension is made to the Corti and Debenedetti subcell constraint algorithm [D. S. Corti and P. Debenedetti, Chem. Eng. Sci. 49, 2717 (1994)], which restricts the maximum allowed local density at any point in a simulation box. The maximum allowed local density at a point in a simulation box is defined by the maximum number of particles Nm allowed to appear inside a sphere of radius R, with this point as the center of the sphere. Both Nm and R serve as extra thermodynamic variables for maintaining a certain degree of spatial homogeneity in a supersaturated system. In a restricted canonical ensemble, at a given temperature and an overall density, series of local minima on the Helmholtz free energy surface F(Nm, R) are found subject to different (Nm, R) pairs. The true equilibrium metastable state is identified through the analysis of the formation free energies of Stillinger clusters of various sizes obtained from these restricted states. The simulation results of a supersaturated Lennard-Jones vapor at reduced temperature 0.7 including the vapor pressure isotherm, formation free energies of critical nuclei, and chemical potential differences are presented and analyzed. In addition, with slight modifications, the current algorithm can be applied to computing thermal properties of superheated liquids. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is a major cause of cancer-related deaths worldwide. Emerging evidence has revealed the vital functions of microRNAs (miRNAs) in cancer malignant progressions. miR-375 has been verified to serve as an antioncogene in tumorigenesis and a potential therapeutic target in various types of cancer. In this study, we aimed to determine the role of miR-375 in the regulation of chemoresistance and metastasis of HCC. Differentially expressed miR-375 and NCAPG2 were externally validated using expression data from The Cancer Genome Atlas (TCGA) database. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression levels of miR-375 in HCC tissues and cell lines. miR-375 mimics and NCAPG2-overexpression were transfected into HepG2 and Huh7 cells to establish miR-375 overexpression models. Cell Counting Kit-8, Transwell, and flow cytometry experiments were conducted to monitor cell proliferation, migration, and apoptosis. The targeting relationship between miR-375 and non-SMC condensin II complex subunit G 2 (NCAPG2) was determined by qRT-PCR, western blot, and luciferase reporter gene assay. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were conducted using Gene Set Enrichment Analysis (GSEA). The pathway enrichment analysis was used to predict the potential pathways for further study. miR-375 was significantly downregulated in HCC tissues and cells compared to adjacent tissue and normal hepatocyte cell line respectively while NCAPG2 was upregulated. The targeting relationship was verified by luciferase reporting assay, and miR-375 could target the 3'UTR of NCAPG2 mRNA and effectively suppress NCAPG2 protein expression. Replenishing of miR-375 significantly repressed HCC cell proliferation and migration, and induced cell apoptosis. Overexpression of NCAPG2 recovered those biological abilities in miR-375 overexpressed cells. Collective data suggested that miR-375 served as a tumor suppressor via regulating NCAPG2. Replenishing of miR-375 or knockout of NCAPG2 could be therapeutically exploited for HCC. [ABSTRACT FROM AUTHOR]

Microbial variations in the human gut are harbored in temporal and spatial heterogeneity, and quantitative prediction of spatiotemporal dynamic changes in the gut microbiota is imperative for development of tailored microbiome-directed therapeutics treatments, e.g. precision nutrition. Given the high-degree complexity of microbial variations, subject to the dynamic interactions among host, microbial, and environmental factors, identifying how microbiota colonize in the gut represents an important challenge. Here we present COmputing the DYnamics of microbiota (CODY), a multiscale framework that integrates species-level modeling of microbial dynamics and ecosystem-level interactions into a mathematical model that characterizes spatial-specific in vivo microbial residence in the colon as impacted by host physiology. The framework quantifies spatiotemporal resolution of microbial variations on species-level abundance profiles across site-specific colon regions and in feces, independent of a priori knowledge. We demonstrated the effectiveness of CODY using cross-sectional data from two longitudinal metagenomics studies--the microbiota development during early infancy and during short-term diet intervention of obese adults. For each cohort, CODY correctly predicts the microbial variations in response to diet intervention, as validated by available metagenomics and metabolomics data. Model simulations provide insight into the biogeographical heterogeneity among lumen, mucus, and feces, which provides insight into how host physical forces and spatial structure are shaping microbial structure and functionality. [ABSTRACT FROM AUTHOR]

BACKGROUND: A challenge in developing machine learning regression models is that it is difficult to know whether maximal performance has been reached on the test dataset, or whether further model improvement is possible. In biology, this problem is particularly pronounced as sample labels (response variables) are typically obtained through experiments and therefore have experiment noise associated with them. Such label noise puts a fundamental limit to the metrics of performance attainable by regression models on the test dataset. RESULTS: We address this challenge by deriving an expected upper bound for the coefficient of determination (R2) for regression models when tested on the holdout dataset. This upper bound depends only on the noise associated with the response variable in a dataset as well as its variance. The upper bound estimate was validated via Monte Carlo simulations and then used as a tool to bootstrap performance of regression models trained on biological datasets, including protein sequence data, transcriptomic data, and genomic data. CONCLUSIONS: The new method for estimating upper bounds for model performance on test data should aid researchers in developing ML regression models that reach their maximum potential. Although we study biological datasets in this work, the new upper bound estimates will hold true for regression models from any research field or application area where response variables have associated noise. [ABSTRACT FROM AUTHOR]

Pressure, excess chemical potential, and excess free energy data for different densities of the supersaturated argon vapor at reduced temperatures from 0.7 to 1.2 are obtained by solving the integral equation with perturbation correction to the radial distribution function [F. Lado, Phys. Rev. 135, A1013 (1964)]. For those state points where there is no solution, the integral equation is solved with the interaction between argon atoms modeled by Lennard–Jones potential plus a repulsive potential with one controlling parameter, α exp(-r/σ) and in the end, all the thermal properties are mapped back to the α=0 case. Our pressure data and the spinodal obtained from the current method are compared with a molecular dynamics simulation study [A. Linhart et al., J. Chem. Phys. 122, 144506 (2005)] of the same system. [ABSTRACT FROM AUTHOR]

Pressure, excess chemical potential, and excess free energy, with respect to ideal gas data at different densities of the supersaturated Lennard-Jones particle vapor at the reduced temperature 0.7 are obtained by the restricted canonical ensemble Monte Carlo simulation method [D. S. Corti and P. Debenedetti, Chem. Eng. Sci. 49, 2717 (1994)]. The excess free energy values depend upon the constraints imposed on the system with local minima exhibited for densities below the spinodal density and monotonic variation for densities larger than the spinodal density. The results are compared with a molecular dynamics simulation study [A. Linharton et al., J. Chem. Phys. 122, 144506 (2005)] on the same system. The current study verifies the conclusion drawn by the simulation work that clustering of Lennard-Jones atoms exists even in the vicinity of spinodal. Our method gives an alternative to molecular dynamic simulations for the determination of equilibrium properties of a metastable fluid, especially close to the spinodal, and does not require a very large system to carry out the simulation. [ABSTRACT FROM AUTHOR]

In this paper, we consider a family of second-order elliptic systems subject to a periodically oscillating Robin boundary condition. We establish the qualitative homogenization theorem on Lipschitz domains satisfying a nonresonance condition. We also use the quantitative estimates of oscillatory integrals to obtain the dimension-dependent convergence rates in L2, assuming that the domain is smooth and strictly convex. [ABSTRACT FROM AUTHOR]

Objective: To analyze the changes of hemorheology, haemodynamics and immune function of patients during propofol intravenous anesthesia in the radical resection of colorectal carcinoma and its significance. Methods: The study included 112 patients who underwent radical resection of colorectal carcinoma in our hospital between August 2016 and December 2017, and they were divided into an observation group (N=56) and a control group (N=56) using random number table. Patients in the observation group were given propofol intravenous anesthesia, while patients in the control group received inhalation anesthesia of sevoflurane. Hemorheological and haemodynamical indexes were compared and analyzed before anesthesia (T0), 90 min after induction (T1), 150 min after induction (T2) and 30 min after entering postanesthesia care unit (T3), and the changes of immune function before and after surgery was also observed. Results: The whole blood viscosity under high, medium and low shear rates of the observation group declined significantly compared to that of the control group at T1, T2 and T3 (P<0.05). The heart rate (HR) and systolic pressure (SPB) of the observation group significantly decreased at T2 compared to those at T1 (P<0.05), but recovered to the level observed at T0 at T3. The diastolic blood pressure (DBP) of the two groups at T1, T2 and T3 was not significantly different with that at T0 (P>0.05). The levels of CD45RA+ and CD45RO+ of both groups had a significant decrease at the end of the surgery compared to before anesthesia (P<0.05); the levels of the observation group recovered at the postoperative 72nd h, and the differences with the levels before anesthesia had no statistical significance (P>0.05); the level of CD45RA+ of the control group also recovered at the postoperative 72nd h, but the difference with the level before anesthesia had no statistical significance (P>0.05); the level of CD45RO+ of the control group had a significant decrease, and the difference with the level before anesthesia was statistically significant (P<0.05). The level of CD45RA+/CD45RO+ of the observation group at the end of surgery and the postoperative 72nd h was not significantly different with those before anesthesia (P>0.05). The level of CD45RA+/CD45RO+ of the control group at the postoperative 72nd h showed a significant increase compared to before anesthesia (P<0.05). Conclusion: Propofol intravenous anesthesia has a significant improvement effect on hemorheology before radical resection of colorectal carcinoma and has a small influence on haemodynamics. Moreover it is beneficial to the recovery of immune function. The therapy is worth promotion. [ABSTRACT FROM AUTHOR]

In order to better serve cotton farmers, green prevention and control technologies of pests are formulated according to the sowing, seedling and adult stages of cotton from the aspects of ecological prevention and control, physical prevention and control, biological control and scientific use of pesticides, thus realizing green prevention and control of pests during the whole growth period of cotton. [ABSTRACT FROM AUTHOR]

We consider a family of second-order elliptic operators {Lε} in divergence form with rapidly oscillating and almost-periodic coefficients in Lipschitz domains. By using the compactness method, we show that the uniform W1,p estimate of second-order elliptic systems holds for 2n/n+1 -δ < p < 2n/n-1 + δ; the ranges are sharp for n = 2 or n = 3. In the scalar case we obtain that the W1,p estimate holds for 3/2 - δ < p < 3 + δ if n ≥ 3, and 4/3 - δ < p < 4 + δ if n = 2; the ranges of p are sharp. [ABSTRACT FROM AUTHOR]

The ability to tolerate environmental stress may determine invasion success of alien species. Comparative data on physiological thermal tolerance between native and invasive vertebrates are quite limited. Here, we assessed the difference in thermal tolerance between a native (Mauremys reevesii) and an invasive (Trachemys scripta elegans) freshwater turtle species. We incubated eggs of M. reevesii and T. scripta elegans from different cohorts at 29 °C, and measured the critical thermal minimum (CTMin) and maximum (CTMax) of hatchlings. Our results preliminarily showed that the hatchlings of T. scripta elegans had a greater high-temperature tolerance and wider tolerance range than the hatchlings of M. reevesii; in the two-cohort system, individuals from the high-latitude cohort seemed to have greater low-temperature tolerance but similar high-temperature tolerance compared with those from the low-latitude cohort. Relatively greater thermal tolerance ability for T. scripta elegans might reflect its environmental adaptability to thermal stress.. [ABSTRACT FROM AUTHOR]

In this study, the effects of surfactants on the hydrodynamic characteristics of bubbles in shear-thinning fluids at low Reynolds number (Re<50) are investigated. The bubble terminal velocity and drag coefficient of bubble in clean and contaminated carboxymethylcellulose (CMC) solutions are obtained using a high-speed camera for examining differences. The results show that the existence of surfactant could reduce the terminal velocity of bubble at small volume (0.25wt% CMC: <100 mm3; 0.50wt% CMC: <110 mm3), attributed to stiffening the bubble interface. However, this negative effect decreases and finally disappears with increasing bubble volume. The drag coefficient curves of the bubble in contaminated CMC solution exhibit behavior similar to that exhibited by a solid sphere at Re<10, indicating that internal circulation flow is absent at the bubble interface as compared to that in clean CMC solution. However, for 10Re to 16/Re in contaminated CMC solution is observed, which is easy at low SDS concentrations and high CMC concentrations. [ABSTRACT FROM AUTHOR]

We consider a family of second-order elliptic operators {Lε} in divergence form with rapidly oscillating and periodic coefficients in Lipschitz and convex domains in Rn. We are able to show that the uniform W1,p estimate of second order elliptic systems holds for 2n/n+1 - δ < p < 2n n-1 + δ where δ > 0 is independent of ε and the ranges are sharp for n = 2, 3. And for elliptic equations in Lipschitz domains, the W1,p estimate is true for 3/2 - δ < p < 3 + δ if n ≥ 4, similar estimate was extended to convex domains for 1 < p < ∞. [ABSTRACT FROM AUTHOR]

Lambertian surfaces represent an important assumption when constructing thermal radiance transfer equations for remote sensing observations of ground surface temperatures. We identify the properties of ground surfaces in thermal infrared regions as Lambertian surfaces via field experiments. Because Lambertian surfaces present homogeneous thermal emissions levels in hemispheric directions for a specific ground surface under specific kinetic temperatures and emissions, we conducted a series of field experiments to illustrate the properties of such ground surfaces. Four typical ground surfaces were selected for the experiments to observe thermal emissions: bare soil, grass, water, and concrete. Radiance thermometers were used to observe ground emissions from seven directions: 30°, 45°, 60°, 90°, 120°, 135°, and 150°. Solar zenith angles were considered for the observation of ground emissions. Experiments were conducted in five different regions of China (Beijing, Nanjing, Xilinguole, Yongzhou, and Jiangmen) during both daytime and nighttime. To determine whether different observation angles have significantly different effects on radiance, statistical analyses (ANOVA and Friedman test) were conducted. Post hoc multiple comparison tests and pairwise multiple comparisons were also conducted to examine the various pairings of observation angles and to measure the radiance differences. Roughly half of the radiance groups of all observed sites were tested via an ANOVA, and the remaining groups with unequal variances were subjected to the Friedman test. The results indicate that statistically significant differences in the radiance levels occurred among the seven angles for almost all of the sites (39 of the 40 groups). The results of our experiments indicate that the selected ground surfaces, especially the grass and the bare soil, may not behave with Lambertian properties in the thermal infrared region. This is probably attributed to the roughness of the selected surface, because we found that roughness is an important factor affecting the observed magnitude of thermal emission from different directions of the ground surface under study. Therefore, whether or not a terrestrial surface can be assumed to be a Lambertian surface should be based on their geometric structure. When the surface is relatively smooth, we can say that it is close to the Lambertian property in thermal emission. [ABSTRACT FROM AUTHOR]

Thermal acclimatory adjustments of locomotor performance and thermal tolerance occur commonly in ectothermic animals. However, few studies have investigated ontogenetic differences in these acclimatory responses, and thus, their causes remain unclear. In this study, juvenile and adult Chinese fire-bellied newts (Cynops orientalis) were acclimated to one of two temperatures (16 or 24 °C) for 4 weeks to examine ontogenetic differences in acclimation effect on burst swimming speed, and critical thermal minimum (CTMin) and maximum (CTMax). Swimming performance was thermally acclimated in both juvenile and adult C. orientalis. Adult newts had greater absolute swimming speeds than juveniles, which may simply result from their larger sizes. Cold acclimation enhanced low-temperature resistance, and warm acclimation enhanced high-temperature resistance in both juveniles and adults. Despite no ontogenetic difference in CTMin, adult newts had greater CTMax and acclimation response ratio than juveniles, indicating their greater abilities to withstand extreme high temperatures and manage rapid temperature shifts. Ontogenetic change in the thermal acclimatory responses of newts may be related to changes in the thermal environment they experience. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the imaging findings of 15 cases of malignant fibrous histiocytoma (MFH) of the head and neck, in order to better understand the tumor characteristics based on c omputed t omography (CT) and magnetic resonance imaging (MRI). CT (n=11) and MRI (n=4) images from 15 patients with histologically diagnosed MFH of the head and neck were retrospectively analyzed. The imaging characteristics were analyzed and compared among different histological subtypes. The lesions were primarily located in the maxillary sinus in 5 patients, the ethmoid sinus in 1 patient, the infratemporal fossa in 2 patients, the neck in 4 patients, the left mandible in 1 patient, the gingiva in 1 patient and the epiglottis in 1 patient. A total of 4 cases were associated with radiotherapy. All the lesions were ill-defined, ranging in size from 2.1 to 5.1 cm in the largest diameter. Bone fractures were evident in 9 cases. The attenuation, signal and enhancement patterns varied, although inflammatory MFH exhibited prolonged enhancement in dual-phase enhanced CT scans. MFH of the head and neck is rare but may be associated with radiotherapy. Although the imaging manifestations of MFH are various and non-specific, inflammatory MFH exhibits prolonged enhancement on dual-phase enhanced CT scans. [ABSTRACT FROM AUTHOR]

PURPOSE We aimed to investigate the magnetic resonance imaging (MRI) appearance of inflammatory myofibroblastic tumors (IMTs) in the maxillofacial region in order to improve diagnostic quality and resection efficacy. MATERIALS AND METHODS Ten cases of pathologically identified IMTs were analyzed by MRI. The MRI features were examined, including tumor location, tumor shape, tumor margins, and involvement of the surrounding tissues. RESULTS Of ten masses investigated in this study, eight masses were irregular neoplasms with unclear margins and two masses, in the parotid gland, were regular neoplasms with clear margins. Precontrast T1 -weighted images of all ten masses exhibited isointense signals compared to the adjacent tissue, while contrast-enhanced T1 -weighted images showed strong enhancement. Six masses were hypointense and four masses were slightly hyperintense in T2-weighted images. Involvement of the adjacent structures was observed in eight of ten cases. Meanwhile, two patients experienced intracranial involvement. CONCLUSION IMTs are rare tumors in the maxillofacial region, displaying a number of distinct MRI characteristics. Most importantly, they display low T2 signal intensity and strong enhancement, and they frequently invade surrounding structures. Thus, MRI can improve the accuracy of IMT diagnoses and provide critical information for surgical planning. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Otolaryngology -- Head & Neck Surgery is the property of Sage Publications Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A BaF2hollow nest-like nanostructure has been successfully synthesized, for the first time, viaa facile sonochemical route from aqueous solution using EDTA as complexing reagent and CTAB as surfactant. Reaction conditions, such as concentrations of complexing reagent and surfactant, were found to have a close relation to the morphologies of final products. The ultrasound-induced self-assembly growth procedure has been proposed for the possible formation mechanism. The BaF2hollow structures showed enhanced photoluminescence compared to the solid structure. [ABSTRACT FROM AUTHOR]

The core/shell-type ZnO nanosphere/CdS nanorod and ZnO nanosphere/CdS nanoparticle composites have been selectively prepared through a simple ultrasound-assisted solution phase conversion process using monodispersed ZnO nanospheres as a starting reactant and in situtemplate. The formation mechanism of the products is closely connected with the sonochemical effect of ultrasonic irradiation. The photoluminescence and electrogenerated chemiluminescence properties of the as-prepared core/shell structures were investigated. [ABSTRACT FROM AUTHOR]

A wide‐band reflective polarizer from glassy siloxane cyclic side‐chain liquid crystals with stable optical properties was developed. The pitch gradient that formed was first stored by rapid cooling, which, by preventing the crystallization of glassy materials, was a very easy way of keeping the molecular arrangement. Then, the polymer network that formed through UV‐initiated chain crosslinking of the photopolymerizable monomers in the reflective polarizer further stabilized the cholesteric structure stored by the former rapid cooling. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [ABSTRACT FROM AUTHOR]

Lead tungstate (PbWO4) an important inorganic scintillator, was synthesized via a mild sonochemical route from an aqueous solution of lead acetate and sodium tungstate in the presence of complexing agents under ambient air. X-ray diffraction (XRD), transmission electron microscope (TEM) and photoluminescence (PL) were used to characterize the products. The as-prepared PbWO4 nanocrystals crystallize in a tetragonal structure and have an average crystal size of ca. 10 nm. [ABSTRACT FROM AUTHOR]

Microwave-assisted synthesis of ferrocenyl pyrrolizidines containing cyano groups has been accomplished in moderate yields via a facile [3+2]-cycloaddition reaction of several azomethine ylides, derived from aromatic aldehydes and proline, with 1, 1-dicyano-2-ferrocenylethene as the dipolarophile. This method offers several advantages such as short reaction time and simple procedure. [ABSTRACT FROM AUTHOR]

A straightforward and practical approach is established for the synthesis of 2-(1H-indol-3-yl)pyridine derivatives achieved through the one-pot three-component reaction of chalcone, 3-(2-cyanoacetyl)-1H-indole and ammonium acetate. This method offers several advantages such as short reaction time, high yields, and simple procedure. [ABSTRACT FROM AUTHOR]

Since the true ground state of hadrons may be strange quark matter (SQM), pulsars may actually be strange stars rather than neutron stars. According to this SQM hypothesis, strange planets can also stably exist. The density of normal matter planets can hardly be higher than 30 g cm−3. They will be tidally disrupted when the orbital radius is less than ∼5.6 × 1010 cm, or when the orbital period (Porb) is less than ∼6100 s. However, an SQM planet can safely survive even when it is very close to the host, due to its high density. This feature can help us identify SQM objects. Here, we have tried to search for SQM objects among close-in exoplanets orbiting around pulsars. It is found that four pulsar planets (XTE J1807-294 b, XTE J1751-305 b, PSR 0636 b, PSR J1807-2459A b) completely meet the criterion of Porb < 6100 s, and are thus good candidates for SQM planets. The periods of two other planets (PSR J1719-14 b and PSR J2051-0827 b) are only slightly larger than the criterion value. They could be regarded as potential candidates. Additionally, we find that the periods of five white dwarf planets (GP Com b, V396 Hya b, J1433 b, WD 0137-349 b, and SDSS J1411+2009 b) are less than 0.1 day; they might also be SQM planets. Gravitational wave emissions from these close-in planetary systems are calculated from the view of various gravitational wave detectors. [ABSTRACT FROM AUTHOR]

The characteristics of the spectral evolution of the prompt emission of gamma-ray bursts (GRBs), which are closely related to the radiation mechanism (synchrotron or photosphere), are still an unsolved subject. Here, by performing the detailed time-resolved spectral fitting of GRB 131231A, which has a very bright and well-defined single pulse, some interesting spectral evolution features have been found. (i) Both the low-energy spectral index α and the peak energy Ep exhibit the “flux-tracking” pattern (“double-tracking” characteristics). (ii) The parameter relations, i.e., F (the energy flux)-α, F–Ep, and Ep–α, along with the analogous Yonetoku Ep–Lγ,iso relation for the different time-resolved spectra, show strong monotonous (positive) correlations, both in the rising and the decaying phases. (iii) The values of α do not exceed the synchrotron limit (α = −2/3) in all slices across the pulse, favoring the synchrotron origin. We argue that the one-zone synchrotron emission model with the emitter streaming away at a large distance from the central engine can explain all of these special spectral evolution characteristics. [ABSTRACT FROM AUTHOR]

The broadband afterglow of GW170817/GRB 170817A is believed to be from an off-axis structured jet. The central engine of a gamma-ray burst usually launches a pair of outflows that move oppositely. It is reasonable to consider the emission from double-sided structured jets, with a near-jet moving toward us and a counter-jet moving away from us. Assuming that the two branches of the jet have the same physical parameters, we have calculated their radio emission. It is found that the counter-jet component will emerge in the radio light curves ∼2500 days post-merger. It typically leads to a plateau in the light curve, thus it could be revealed by high accuracy radio observations. We have also considered the possibilities that both branches have different parameters, and found that if some of the physical parameters of the counter-jet are evaluated more favorably than those of the near-jet, then the counter-jet emission will be enhanced and will clearly show up as an obvious plateau or even a rebrightening. For example, when the circumburst medium encountered by the counter-jet is assumed to be 100 times denser than that of the near-jet, a remarkable radio plateau will appear at ∼600 days. However, in X-ray bands, the counter-jet component is generally too faint to be discerned. It is argued that the late radio observations of GW170817/GRB 170817A can help determine the key parameters and diagnose the environment of the event. [ABSTRACT FROM AUTHOR]