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Diagnostics ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 87
Author(s):  
Eunae Lee ◽  
Dong Sik Kim

In fluoroscopic imaging, we can acquire X-ray image sequences using a flat-panel dynamic detector. However, lag signals from previous frames are added to the subsequently acquired images and produce lag artifacts. The lag signals also inflate the measured noise power spectrum (NPS) of a detector. In order to correct the measured NPS, the lag correction factor (LCF) is generally used. However, the nonuniform temporal gain (NTG), which is from inconsistent X-ray sources and readout circuits, can significantly distort the LCF measurements. In this paper, we propose a simple scheme to alleviate the NTG problem in order to accurately and efficiently measure the detector LCF. We first theoretically analyze the effects of NTG, especially on the correlation-based LCF measurement methods, where calculating the correlation coefficients are required. In order to remove the biases due to NTG, a notion of conditional covariance is considered for unbiased estimates of the correlation coefficients. Experiments using practical X-ray images acquired from a dynamic detector were conducted. The proposed approach could yield accurate LCF values similarly to the current approaches of the direct and U-L corrections with a low computational complexity. By calculating the correlation coefficients based on conditional covariance, we could obtain accurate LCF values even under the NTG environment. This approach does not require any preprocessing scheme of the direct or U-L correction and can provide further accurate LCF values than the method of IEC62220-1-3 does.


Author(s):  
Xinfang Li ◽  
Jianning Liu ◽  
Osei Seth ◽  
Heng-Na Xiong ◽  
Qingshou Tan ◽  
...  

Abstract We propose a simple scheme to realize the persistent spin-nematic squeezing in a spinor Bose-Einstein condensate by rapidly turning-off the external magnetic field at a time that maximal spin-nematic squeezing occurs. We observe that the optimal spinnematic squeezing can be maintained in a nearly fixed direction. For a proper initial magnetic field, the optimal squeezing can be obviously enhanced. We further construct a spin-mixing interferometer, where the quantum correlation of the squeezed state (generated by our scheme) is fully utilized in the phase measurement, and show the phase sensitivity of the interferometer has a significant enhancement.


Author(s):  
Sebastian T. Glavind ◽  
Juan G. Sepulveda ◽  
Michael H. Faber

Author(s):  
Kostiantyn V. Domasevitch ◽  
Ganna A. Senchyk ◽  
Andrey B. Lysenko ◽  
Eduard B. Rusanov

The structure of the title salt, ammonium carbamoylcyanonitrosomethanide, NH4 +·C3H2N3O2 −, features the co-existence of different hydrogen-bonding patterns, which are specific to each of the three functional groups (nitroso, carbamoyl and cyano) of the methanide anion. The nitroso O-atoms accept as many as three N—H...O bonds from the ammonium cations [N...O = 2.688 (3)–3.000 (3) Å] to form chains of fused rhombs [(NH4)(O)2]. The most prominent bonds of the carbamoyl groups are mutual and they yield 21 helices [N...O = 2.903 (2) Å], whereas the cyano N-atoms accept hydrogen bonds from sterically less accessible carbamoyl H-atoms [N...N = 3.004 (3) Å]. Two weaker NH4 +...O=C bonds [N...O = 3.021 (2), 3.017 (2) Å] complete the hydrogen-bonded environment of the carbamoyl groups. A Hirshfeld surface analysis indicates that the most important interactions are overwhelmingly O...H/H...O and N...H/H...N, in total accounting for 64.1% of the contacts for the individual anions. The relatively simple scheme of these interactions allows the delineation of the supramolecular synthons, which may be applicable to crystal engineering of hydrogen-bonded solids containing polyfunctional methanide anions.


Oncoreview ◽  
2021 ◽  
Vol 11 (3(43)) ◽  
pp. 61-67
Author(s):  
Radosław Grabysa ◽  
Agnieszka Chmielewska

Modern antiandrogens: abiraterone acetate (inhibitor of CYP17 cytochrome) and enzalutamide (irreversible inhibitor of androgen receptor) are the drugs that are increasingly often administered in treatment of castration-resistant prostate cancer. Despite their clinical efficacy, especially in terms of prolonged survival and improved quality of life of patients, they pose of problem for a practicing oncologist such as possible cardiovascular complications (particularly arterial hypertension), which may lead to the cessation of this form of therapy. This article provides a brief overview of the mechanisms responsible for the above complications, including practical recommendations in the event such complications arise. A simple scheme of action for control of cardiovascular risk factors has been presented, which can improve the prognosis in this population of patients.


Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5796
Author(s):  
Dong-Hoon Kim ◽  
Hyung-Jung Kim ◽  
Jae-Han Lim

To meet the increasing demands for remote sensing, a number of radar systems using Linear Frequency Modulation (LFM) waveforms have been deployed, causing the problem of depleting frequency resources. To address this problem, several researchers have proposed the Spectrum Shared Radar System (SSRS) in which multiple radars share the same frequency band to transmit and receive their own signals. To mitigate the interferences caused by the signal transmission by other radars, SSRS employs orthogonal waveforms that inherit the orthogonality of the waveforms from orthogonal codes. However, the inherited orthogonality of the codes is significantly reduced when incorporating LFM waveforms with the codes. To solve this problem, in this paper, we propose a novel but simple scheme for generating a set of optimized coded LFM waveforms via new optimization framework. In the optimization framework, we minimize the weighted sum of autocorrelation sidelobe peaks (ASP) and cross-correlation peaks (CP) of the coded LFM waveforms to maximize the orthogonality of the waveforms. Through computer simulations, we show that the waveforms generated by the proposed scheme outperform the waveforms created by previous proposals in terms of ASP and CP.


2021 ◽  
Vol 598 ◽  
pp. 126296
Author(s):  
Jeongha Park ◽  
David Cross ◽  
Christian Onof ◽  
Yuting Chen ◽  
Dongkyun Kim

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Dahao Wang ◽  
Peng Zhang ◽  
Xifan Mei ◽  
Zhenhua Chen

Abstract In this article, we propose a simple scheme of using berberine (BBR) to modify porous calcium phosphate ceramics (named PCPC). These BBR molecules regulate the crystallization of hydroxyapatite nanorods on PCPC. We found that these nanorods and the adsorbed BBR changed the interface micro-environment of PCPC by SEM images. The microenvironment of PCPC surface is essential for promoting BMSCs’ proliferation and differentiation. These results demonstrated that PCPC/BBR markedly improved the bone regeneration of osteoporosis rats. Moreover, PCPC/BBR had significantly increased the expression levels of ALP, osteocalcin and bone morphogenetic protein2 and RUNX2 in BMSCs originated from osteoporosis rats.


2021 ◽  
Author(s):  
Angelo De Santis ◽  
Saioa A. Campuzano ◽  
Gianfranco Cianchini ◽  
Domenico Di Mauro ◽  
Dedalo Marchetti ◽  
...  

<p>In-situ magnetic field and electron density, as observed by Swarm and CSES satellites, are analyzed to identify possible anomalies in geomagnetic quiet time with respect to the ionospheric background. To avoid detecting possible anomalies induced by auroral activity we investigate regions between +50 and -50 degrees in magnetic latitude. Then a superposed epoch and space approach is applied to this anomaly dataset with respect to their time and space distance from shallow M5.5+ earthquakes occurred in about last 6 years. A comparison with analogous homogeneous random distribution of anomalies shows that the real anomaly concentrations found before the occurrence of earthquakes are statistically significant. In addition, we find that, in general, the anticipation times of the ionospheric precursors scale with the earthquake magnitude, confirming the validity of the Rikitake law for ionospheric signals, previously valid for ground precursors. We also find that the anomaly duration seems to depend on the magnitude of the impending earthquake. Finally, we propose a simple scheme of potential earthquake forecast on the base of the previously mentioned characteristics.</p>


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