Living Self-Assembly of Metastable and Stable Two-Dimensional Platelets from a Single Small Molecule.

This study reports the design of a donor-acceptor (D-A) molecule with two fluorene units on each side of a benzothiadiazole moiety, which allows multiple intermolecular interactions to compete with one another so as to induce the evolution of the metastable 2D platelets to the stable 2D platelets during the self-assembly of the D-A molecule. Importantly, the living seeded self-assembly of metastable and stable 2D structures with precisely controlled sizes can be conveniently achieved using an appropriate supersaturated level of a solution of the D-A molecule as the seeded growth medium that can temporarily hold the almost-proceeding spontaneous nucleation from competing with the seeded growth. The stable 2D platelets with smaller area sizes exhibit higher sensitivity to gaseous dimethyl sulfide, illustrating that the novel living self-assembly method provides more available functional structures with controlled sizes for practical applications. The key finding of this study is that the new living methodology is separated into two independent processes: the elaborate molecular design for various crystalline structures as seeds and the application of a supersaturated solution with appropriate levels as the growth medium to grow the uniform structures with controlled sizes; this would make convenient and possible the living seeded self-assembly of rich 1D, 2D, and 3D architectures.

Incidence rate and implications of splenic ischemia during sleeve gastrectomy and its related procedure.

Splenic ischemia (SI) is a common finding during sleeve gastrectomy (SG) procedures; however, reports are still lacking. In this study, we retrospectively analyzed our SG patients to understand better the incidence rate and implications of SI. Patients' data from the beginning of the year 2021 until December 2022 that underwent bariatric surgery at our university hospital were retrospectively analyzed. Patient surgery video was reviewed by all the authors to investigate the incidence of SI. Thereafter, the corresponding patient age, height, weight, BMI, and their postoperative day 1 (POD1) temperature and blood routine test results (patients were routinely discharged at POD2) were collected and analyzed. 204 patients were included in this study. The mean age and preoperative BMI were 31.7 ±â€…7.4 years old and 38.8 ±â€…5.6 kg/m2, respectively. SI was observed in 18 cases (8.8%). 30-day readmission rate was seen in 3 patients (1.5%, all without SI during the primary surgery). There was no statistical difference with regard to the POD1 temperature and blood test results between the patients with and without SI. The incidence of SI during sleeve gastrectomy-related procedures is a common finding in our study. We did not observe significant differences postoperatively between the patients with and without SI before discharge. Further study is needed to understand the mechanism for the incidence of SI during SG.

Concentric hollow multi-hexagonal platelets from a small molecule.

The creation of well-defined hollow two-dimensional structures from small organic molecules, particularly those with controlled widths and numbers of segments, remains a formidable challenge. Here we report the fabrication of the well-defined concentric hollow two-dimensional platelets with programmable widths and numbers of segments through constructing a concentric multiblock two-dimensional precursor followed by post-processing. The fabrication of concentric multi-hexagons two-dimensional platelets is realized by the alternative heteroepitaxial growth of two donor-acceptor molecules. Upon ultraviolet irradiation, one of the two donor-acceptor molecules can be selectively oxidized by singlet oxygen generated during the process, and the oxidized product becomes more soluble due to increased polarity. This allows for selective removal of the oxidized segments simply by solvent dissolution, yielding hollow multiblock two-dimensional structures. The hollow two-dimensional platelets can be utilized as templates to lithograph complex electrodes with precisely controlled gap sizes, thereby offering a platform for examining the optoelectronic performance of functional materials.

Fluorescent sensor based on solid-phase extraction with negligible depletion: A proof-of-concept study with amines as analytes.

This paper describes the development and proof-of-concept testing of an easy-to-use trace analysis technique, namely F-SPE, by coupling fluorescent sensor with solid phase extraction (SPE). F-SPE is a two-step methodology that concentrates an analyte from a liquid sample onto a fluorophore-modified membrane and measures the amount of analyte from the extent the extracted analyte quenches the emission of the fluorophore. By applying the principle of negligible depletion (ND) intrinsic to SPE, the procedure of F-SPE for analyzing a sample can be markedly simplified while maintaining the ability to detect analytes at low limits of detection (LOD). The merits of this approach are demonstrated by impregnating a SPE membrane with a perylene diimide (PDI) fluorophore, N,N'-di(nonyldecyl)-perylene-3,4,9,10-tetracarboxylic diimide (C9/9-PDI), for the low-level detection of organic amines (e.g., aniline) and amine-containing drugs (e.g., Kanamycin). The sensing mechanism is based on the donor-acceptor quenching of PDI by amines, which, when coupled with the concentrative nature of SPE, yields LODs for aniline and Kanamycin of 67 nM (∼6 ppb) and 32 nM (∼16 ppb), respectively.

Tribology Performance of Surface Texturing Plunger.

Plunger pumps are widely used in oil pumping units around the world. The water content of the wellbore is increasing along with the development progress, so the lubricating capacity of the well fluids between the plunger and barrel is decreasing correspondingly. Commonly, the substrate material of the plunger and barrel are stainless steel, and the plunger surface is usually covered with nickel-based coating. Therefore, the performance of the plunger and barrel has been affected due to poor lubrication and eccentric wear. Non-smooth surfaces have been proven to improve the tribology performance in many cases. A surface texturing plunger covered with specific dimples has been prepared by using laser surface texturing technology. The morphology of the surface texturing plunger was characterized and analyzed. The tribology performance of surface texturing plunger samples was tested using standard friction and wear test machines with oil and water lubrication, respectively. The results indicated that surface texturing could effectively reduce the coefficient of friction, and the wear resistance of the surface textured samples has been improved to some extent.