63 research outputs found
A moderate spin for the black hole in X-ray binary MAXI J1348-630 revealed by Insight-HXMT
MAXI J1348-630 is a low-mass X-ray black hole binary located in the Galaxy
and undergone the X-ray outburst in 2019. We analyzed the observation data in
very soft state during the outburst between MJD 58588 and MJD 58596 based on
the Insight-HXMT observations from 2 -- 20 keV via the continuum fitting method
to measure the spin of the stellar-mass black hole in MAXI J1348-630. The inner
disk temperature and the apparent inner disk radius were found to be and from the observation data modeled by
the multicolor disc blackbody model. Assuming the distance of the source , the mass of the black hole , and the
inclination of the system , the spin is determined to be
for fixing hardening factor at 1.6 and
. Besides, considering the uncertainty of
the parameters of this system, with the Monte Carlo analysis, we
still confirm the moderate spin of the black hole as
. Some spectral parameters (e.g., column
density and hardening factor) which could affect the measurements of the BH
spin are also briefly discussed.Comment: 10 pages, 14 figures, 5 tables, accept for publication in MNRA
Channel sensing for holographic MIMO surfaces based on interference principle
The Holographic Multiple-Input and Multiple-Output (HMIMO) provides a new
paradigm for building a more cost-effective wireless communication
architecture. In this paper, we derive the principles of holographic
interference theory for electromagnetic wave reception and transmission,
whereby the optical holography is extended to communication holography and a
channel sensing architecture for holographic MIMO surfaces is established.
Unlike the traditional pilot-based MIMO channel estimation approaches, the
proposed architecture circumvents the complicated processes like filtering,
analog to digital conversion (ADC), down conversion. Instead, it relies on
interfering the object waves with a pre-designed reference wave, and therefore
reduces the hardware complexity and requires less time-frequency resources for
channel estimation. To address the self-interference problem in the holographic
recording process, we propose a phase shifting-based interference suppression
(PSIS) method according to the structural characteristics of communication
hologram and interference composition. We then propose a Prony-based multi-user
channel segmentation (PMCS) algorithm to acquire the channel state information
(CSI). Our theoretical analysis shows that the estimation error of the PMCS
algorithm converges to zero when the number of HMIMO surface antennas is large
enough. Simulation results show that under the holographic architecture, our
proposed algorithm can accurately estimate the CSI in multi-user scenarios
ajnmmi1106003
Abstract: Molecular imaging allows direct visualization of targets and characterization of cellular pathways, as long as a high signal/background ratio can be achieved, which requires a sufficient amount of probes to accumulate in the imaging region. The Asn-Gly-Arg (NGR) tripeptide selected by phage display can specifically target tumor vasculature. Recognizing the aminopeptidase N (APN or CD13) receptor on the membrane of tumor cells, the peptide can be further internalized into cytoplasma by the endosomal pathway. Hence NGR can serve as an ideal candidate for tumor imaging, once it is conjugated with fluorescent or radiolabeled imaging probes. Herein, we highlight some recent developments of NGR peptide based imaging of tumors. Although still in the preliminary stage, some NGR probes have shown potential as promising agents in future clinical applications
Superiority of integrated cervicothoracic immobilization in the setup of lung cancer patients treated with supraclavicular station irradiation
ObjectiveTo investigate the superiority of the integrated cervicothoracic immobilization devices (ICTID) on the mobility of the supraclavicular station in lung cancer patients requiring both primary lung lesion and positive supraclavicular lymph nodes irradiation.MethodsOne hundred patients with lung cancer were prospectively enrolled in the study. The following four different fixation methods are used for CT simulation positioning: thoracoabdominal flat immobilization device fixation with arms lifting (TAFID group), head-neck-shoulder immobilization device fixation with arms on the body sides (HNSID group), ICTID fixation with arms on the body sides (ICTID arms-down group), and n ICTID fixation with arms lifting (ICTID arms-up group). Cone-beam computed tomography (CBCT) images are taken daily or weekly before treatment, to assess anatomical changes during the radiotherapy course.ResultsThe translation errors in X (left-right direction), Y (head-foot direction), and Z (abdomen-back direction) directions of the ICTID arms-up, TAFID, ICTID arms-down and HNSID groups were (0.15 ± 0.18) cm, (0.15 ± 0.16) cm, (0.16 ± 0.16) cm, and (0.15 ± 0.20) cm; (0.15 ± 0.15) cm, (0.21 ± 0.25) cm, (0.28 ± 0.23) cm, and (0.27 ± 0.21) cm; (0.13 ± 0.14) cm, (0.15 ± 0.14) cm, (0.17 ± 0.13) cm, and (0.16 ± 0.14) cm, respectively. Among them, the ICTID arms-up group had the minimal setup errors in X direction than those in ICTID arms-down (p=0.001) and HNSID groups (p=0.001), and in Y direction than those in TAFID (p<0.001), and in Z direction than those in ICTID arms-down (p<0.001) and TAFID groups (p=0.034). For the rotational errors of the four groups in the directions of sagittal plane, transverse plane, and coronal plane, the ICTID arms-up group had the smallest setup errors in the sagittal plane than that of TAFID groups and similar rotation setup errors with those of the other three groups.ConclusionFor patients requiring radiation of primary lung lesion and positive supraclavicular lymph nodes, an integrated frame fixation device is preferred the ICTID arms-up methods provide the smallest set up error and satisfied repeatability of body position, compared with TAFID and HNSID
A High-Resolution Whole-Genome Map of Key Chromatin Modifications in the Adult Drosophila melanogaster
Epigenetic research has been focused on cell-type-specific regulation; less is known about common features of epigenetic programming shared by diverse cell types within an organism. Here, we report a modified method for chromatin immunoprecipitation and deep sequencing (ChIP–Seq) and its use to construct a high-resolution map of the Drosophila melanogaster key histone marks, heterochromatin protein 1a (HP1a) and RNA polymerase II (polII). These factors are mapped at 50-bp resolution genome-wide and at 5-bp resolution for regulatory sequences of genes, which reveals fundamental features of chromatin modification landscape shared by major adult Drosophila cell types: the enrichment of both heterochromatic and euchromatic marks in transposons and repetitive sequences, the accumulation of HP1a at transcription start sites with stalled polII, the signatures of histone code and polII level/position around the transcriptional start sites that predict both the mRNA level and functionality of genes, and the enrichment of elongating polII within exons at splicing junctions. These features, likely conserved among diverse epigenomes, reveal general strategies for chromatin modifications
Gamma-AApeptides as a New Class of Peptidomimetics: Synthesis, Structures, and Functions
Peptidomimetics are synthetic oligomers that resemble the activities of peptides. Their advantages over peptides include high stability towards proteolysis and enormous chemical diversity. Over the past two decades, there have been extensive efforts to develop peptide mimics, such as beta-peptides, peptoids, D-peptides, etc. The research on peptidomimetics have led to many important applications in both medicinal and material science. In order to explore new functions, the discovery of peptidomimetics with novel frameworks is essential. We reported the synthesis and evaluation of a new class of peptidomimetics, termed as gamma-AApeptides. Previous studies of gamma-AApeptides have revealed that gamma-AApeptides are highly resistant to proteolysis, and are highly amendable to chemical diversification. However, new biological activities and folding properties of gamma-AApeptides still need to be explored. In order to expand the potential of gamma-AApeptides in chemical biology and medicinal chemistry, I have been focusing on the development of new methods to synthesize linear and cyclic gamma-AApeptides, development of one-bead-one-compound (OBOC) gamma-AApeptide libraries for the discovery of inhibitors against beta-amyloid aggregation, exploring new helical foldamers for the rational design of protein-protein interaction (PPI) inhibitors, and studying cyclic gamma-AApeptides for antimicrobial development
Glutamine Side Chain 13C═18O as a Nonperturbative IR Probe of Amyloid Fibril Hydration and Assembly.
Gamma-AApeptides with potent and broad-spectrum antimicrobial activity
The present invention is directed to a novel class of antimicrobial agents called .gamma.-AApeptides. The current invention provides various categories of .gamma.-AApeptides, for example, linear .gamma.-AApeptides, cyclic .gamma.-AApeptides, and lipidated .gamma.-AApeptides. .gamma.-AApeptides of the current invention are designed to exert antimicrobial activity while being stable and non-toxic. .gamma.-AApeptides also do not appear to lead to the development of microbial resistance in treated microorganisms. Thus, the disclosed .gamma.-AApeptides can be used for the treatment of various medical conditions associated with pathogenic microorganisms
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