Coronavirus disease 2019 (COVID-19) outbreak, first reported in Wuhan, China, has rapidly swept around the world just within a month, causing global public health emergency. In diagnosis, chest computed tomography (CT) manifestations can supplement parts of limitations of real-time reverse transcription polymerase chain reaction (RT-PCR) assay. Based on a comprehensive literature review and the experience in the frontline, we aim to review the typical and relatively atypical CT manifestations with representative COVID-19 cases at our hospital, and hope to strengthen the recognition of these features with radiologists and help them make a quick and accurate diagnosis.

The coronavirus disease (COVID-19) is rapidly spreading all over the world, and has infected more than 1,436,000 people in more than 200 countries and territories as of April 9, 2020. Detecting COVID-19 at early stage is essential to deliver proper healthcare to the patients and also to protect the uninfected population. To this end, we develop a dual-sampling attention network to automatically diagnose COVID-19 from the community acquired pneumonia (CAP) in chest computed tomography (CT). In particular, we propose a novel online attention module with a 3D convolutional network (CNN) to focus on the infection regions in lungs when making decisions of diagnoses. Note that there exists imbalanced distribution of the sizes of the infection regions between COVID-19 and CAP, partially due to fast progress of COVID-19 after symptom onset. Therefore, we develop a dual-sampling strategy to mitigate the imbalanced learning. Our method is evaluated (to our best knowledge) upon the largest multi-center CT data for COVID-19 from 8 hospitals. In the training-validation stage, we collect 2186 CT scans from 1588 patients for a 5-fold cross-validation. In the testing stage, we employ another independent large-scale testing dataset including 2796 CT scans from 2057 patients. Results show that our algorithm can identify the COVID-19 images with the area under the receiver operating characteristic curve (AUC) value of 0.944,

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This study is dedicated to Professor Dr. R. Bruce Martin, University of Virginia, Charlottesville (USA), on the occasion of his 70th birthday, with the very best wishes of the authors for all his future endeavors and with deep appreciation for friendship and unselfish advice provided over many years to H.S. and B.L.Abstract: The effect of Ni 2 , Cu 2 , and cis-a 2 Pt 2 or trans-a 2 Pt 2 (where a NH 3 or CH 3 NH 2 ), if coordinated to the N7 site of guanine residues, on the acid ± base properties of complexes containing guanine derivatives as ligands is considered. The various acidity constants were determined by potentiometric pH titrations. Over 60 acidity constants are listed; about half of these are new. In many instances micro acidity constants have been derived that allow a quantification of the intrinsic acid ± base properties of a certain site, which are otherwise blurred by the pK a values of overlapping buffer regions. This material allows many comparisons; among these is the observation that the acidifying properties of (N7)-coordinated divalent metal ions on the corresponding (N1)H sites in a guanine derivative decrease in the following series:The data also indicate that the effects are similar for guanine and hypoxanthine residues, but that they are more pronounced for adenine derivatives because in the latter case a (N7)-bound M 2 affects a (N1)H site; hence, a further charge effect is operative here. The available material does not yet allow certain prediction of the more subtle differences occurring between the cis and trans isomers of Pt 2 complexes, but replacement of, for example, NH 3 in the coordination sphere of Pt 2 with CH 3 NH 2 has an effect. Of course, as one might expect, the effect of (N7)-bound Pt 2 in guanine nucleotide complexes is smaller on the more remote phosphate groups than it is on the closer (N1)H sites. By evaluation (by means of micro acidity constants) of data available for hypoxanthine derivatives it is also shown that (N1) À -bound Pt 2 has an acidifying effect on the (N7)H site comparable to that of (N7)-coordinated Pt 2 on the (N1)H site.

The stability constants of the 1:1 complexes formed between Mg2+, Ca2+, Ba2+, Mn2+, Co2+, Ni2+, Zn2+, or Cd2+ and AMPS2-, i.e., of the M(AMPS) complexes, were determined by potentiometric pH titrations (25 °C; I = 0.1 M, NaNO3). For the Mn2+/AMPS, Co2+/AMPS, Ni2+/AMPS, and Cd2+/AMPS systems also the protonated species M(H;AMPS)+ were quantified, and for the Zn2+/AMPS system, the stability of the hydroxo species Zn(AMPS)(OH)-, which results from the Zn2+−thio coordination, could be determined. On the basis of previously established log versus p straight-line plots (R-MP2- = simple monophosphate ester ligands without further coordinating groups; Sigel, H.; et al. Helv. Chim. Acta 1992, 75, 2634), it is concluded that the alkaline earth ions in the M(AMPS) complexes are coordinated to the thiophosphate group with the same intensity as to a normal phosphate group. For the M(AMPS) complexes of Mn2+, Co2+, Ni2+, Zn2+, and Cd2+, it is shown by comparison with the corresponding M(AMP) complexes and by employing the mentioned straight-line plots that the stability increase is larger than may be expected due to macrochelate formation, which means that the metal ions also bind to the sulfur atom of the thiophosphate group. The stability increases amount for Mn(AMPS), Zn(AMPS), and Cd(AMPS) to about 0.2, 0.7, and 2.4 log units, respectively, and the estimated approximate percentages of the sulfur-coordinated species are about 30, 80, and 100%, respectively. Furthermore, comparisons between these stability increases and the solubility products for the corresponding metal ion sulfides, MIIS, as well as with the stability increases due to the M2+−thioether interaction observed for the complexes of tetrahydrothiophene-2-carboxylate, which also result in straight-line plots, further support the conclusions about metal ion−sulfur binding in the mentioned M(AMPS) complexes. The indicated correlations allow also an estimate for the extent of the M2+−sulfur interaction in Pb(AMPS) and Cu(AMPS). The various isomers of the M(H;AMPS)+ species are analyzed in a microconstant scheme, and estimations about their formation degrees are presented; for example, for the Cd2+ system, (H·AMPS·Cd)+ is the dominating isomer, which has the proton at N1 and Cd2+ at the thiophosphate group. It is evident that for metal ions like (Mn2+), Zn2+, or Cd2+ the metal ion binding properties of the parent compound AMP2- and its thio analogue AMPS2- differ considerably, and therefore, great care should be exercised in enzymatic studies where AMPS2- is employed as a probe for AMP2- in the presence of metal ions. Regarding studies of ribozymes, it is of interest that plots are presented (pseudo-first-order rate constants versus complex stabilities) which suggest that on top of a sulfur−metal ion interaction during the transition state of the rate-determining step of the hydrolytic cleavage of an oligonucleotide containing a bridged internucleotide 5‘-phosphorothioate RNA linkage also an oxygen−metal ion interaction occurs and that the two effects are “additiv...