Solid-state 13C NMR measurements were made for the B2 and B4 phases of the achiral banana-shaped molecule, P-14-O-PIMB, which exhibits a direct transformation from the B2 phase to the B4 phase. In both phases, an NMR resonance signal assigned to carbonyl carbons of the ester linkages appears as doublet peaks, showing that the two carbonyl carbons are circumstanced in different electronic environments on the NMR time scale. The chemical shifts of the two peaks are 165.6 and 163.9 ppm in the B2 phase, and these values are not changed in the transformation to the low-temperature B4 phase. To explain this distinct splitting of the carbonyl carbon signal, we take three assumptions into account:  (1) the molecules are accommodated in the unique phase, but the conformational exchange between two states takes place slowly; (2) the two side wings of each molecule experience fast interconformational jumps, but their “average conformer” is different, thus giving two different peaks in the spectra; and (3) the individual molecule claims the twisted conformation, where the two carbonyl carbons of the ester moieties are twisted away from each other by rotating out of the molecular core plane with different dihedral angles. From the present 13C NMR results, the first and second possibilities are ruled out, and it is concluded that the banana-shaped molecules assume the twisted conformation, which is attributable to the origin of the chirality of the B2 and B4 phases in the achiral banana-shaped molecular system.

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Background: Microcirculation is a vital sign that supplies oxygen and nutrients to maintain normal life activities. Sepsis typically influences the operation of microcirculation, which is recovered by the administration of medicine injection. Objective: Sepsis-induced variation and recovery of microcirculation are quantitatively detected using microcirculation images acquired by a non-contact imaging setup, which might assist the clinical diagnosis and therapy of sepsis. Methods: In this study, a non-contact imaging setup was first used to record images of microcirculation on the back of model rats. Specifically, the model rats were divided into three groups: (i) the sham group as a control group; (ii) the cecum ligation and puncture (CLP) group with sepsis; and (iii) the CLP+thrombomodulin (TM) group with sepsis and the application of TM alfa therapy. Furthermore, considering the sparsity of red blood cells (RBCs), the blood velocity is estimated by robust principal component analysis (RPCA) and U-net, and the blood vessel diameter is estimated by the contrast difference between the blood vessel and tissue. Results and Effectiveness: In the experiments, the continuous degradation of the estimated blood velocity and blood vessel diameter in the CLP group and the recovery after degradation of those in the CLP+TM group were quantitatively observed. The variation tendencies of the estimated blood velocity and blood vessel diameter in each group suggested the effects of sepsis and its corresponding therapy.

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