Organic polymorphic crystals with multi-stimuli response:excellent mechanical elasticity,novel two-stage heterotropic photochromism and self-reversible acidichromism

Smart multi-stimuli responsive organic materials have become increasingly favored due to their advantages of high stability and easy regulation.In this study,a cyanostilbene derivative((αZ)-2-chloro-α-[(4-methoxyphenyl)methylene]-5-pyridinehyde,TAR)was successfully synthesized,and its polymorphs(TAR-1 and TAR-2)exhibited multiple responsive behaviors under different stimulus conditions.TAR-1 is supposed to have excellent mechanical properties,while TAR-2 shows fascinating heterotropic photochromism(green-cyan-yellow)under different intensities of ultraviolet(UV)irradiation,which has never been reported in previous studies.Further investigation revealed that this was attributed to different degrees of[2+2]cycloaddition induced by UV light.In addition,both polymorphs could be protonated during Trifluoroacetic acid fuming and deprotonate automatically after fuming,accompanied by the significant variation in fluorescence.Finally,two scenarios were designed based on their unique stimuli-responsive properties,which proved their promising potential in fields of information security and anti-counterfeiting encryption.

Properties and Stability of a Meso-Scale Line-Form Disturbance

By using the 3D dynamic equations for small- and meso-scale disturbances, an investigation is performed on the heterotropic instability （including symmetric instability and traversal-type instability） of a zonal line-like disturbance moving at any angle with respect to basic flow, arriving at the following results： （1） with linear shear available, the heterotropic instability of the disturbance will occur only when flow shearing happens in the direction of the line-like disturbance movement or in the direction perpendicular to the disturbance movement, with the heterotropic instability showing the instability of the internal inertial gravity wave; （2） in the presence of second-order non-linear shear, the disturbance of the heterotropic instability includes internal inertial gravity and vortex Rossby waves. For the zonal line-form disturbance under study, the vortex Rossby wave has its source in the second-order shear of meridional basic wind speed in the flow and propagates unidirectionally with respect to the meridional basic flow. As a mesoscale heterotropic instable disturbance, the vortex Rossby wave has its origin from the second shear of the flow in the direction perpendicular to the line-form disturbance and is independent of the condition in the direction parallel to the flow; （3） for general zonal line-like disturbances, if the second-order shear happens in the meridional wind speed, i.e., the second shear of the flow in the direction perpendicular to the line-form disturbance, then the heterotropic instability of the disturbance is likely to be the instability of a mixed Rossby-internal inertial gravity wave; （4） the symmetric instability is actually the instability of the internal inertial gravity wave. The second-order shear in the flow represents an instable factor for a symmetric-type disturbance; （5） the instability of a traversal-type disturbance is the instability of the internal inertial gravity wave when the basic flow is constant or only linearly sheared. With a second or nonlinear vertical shear of the basic flow taken into account, the instability of a traversal-type disturbance may be the instability of a mixed vortex Rossby - gravity wave.

斜交型不稳定谱点分布侧半圆定理及其增长率上界的估计(英文)

Based on the theoretical analysis on the unstable spectrum distribution of heterotropic perturbation, the semi–circle theorem of such spectrum distribution is obtained — the spectrum distributed within an upper semi–circle domain with radius R0 and taking origin as its circle center in the complex plane, and the upper bound estimation of growth rate is given simultaneously. It is found that the smaller the horizontal scale of perturbation is, the higher the model top located, the greater the estimated value of upper bound of such growth rate is. Also the increase of vertical shear of wind and latitude have the positive contribution to the increase of such growth rate. Finally when stratified stability decreases, the relative maximal growth rate increases, while the maximal growth rate decreases instead.

Bleeding Meckel’s in Pregnancy: A Rare Cause of a Rare Phenomenon

Meckel’s diverticulum complicating pregnancy is indeed a rare occurrence. The anatomical and physiological changes that occur in pregnancy make the clinical presentation and preoperative diagnosis of an acute abdomen extremely difficult. Even imaging modalities have to be used with caution keeping in mind the risks associated for both mother and fetus. Treatment of such cases must be prompt and accurate with a high index of suspicion in order to prevent high rate of maternal and fetal morbidity. We report one such case of bleeding of Meckel’s diverticulum. The most common cause of bleeding in a Meckel’s is ectopic gastric mucosa. When we performed an exploratory laparotomy we found to our surprise a bleeding Meckel’s diverticulum. Further investigations revealed a very interesting histopathological report of endometriosis as the cause of bleed.

Study on the Model for Regulation of the Allosteric Enzyme Activity

The effects of activator molecule and repressive molecule on binding process between allosteric enzyme and substrate are discussed by considering the heterotropic effect of the regulating molecule that binds to allosteric enzyme. A model of allosteric enzyme with heterotropic effect is presented. The cooperativity and anticooperativity in the regulation process are studied.