Amide and carboxyl dual-functionalized magnetic microporous organic networks for efficient extraction of cephalosporins

Cephalosporins (CEFs) are a class of widely used toxic antibiotics. Development of a rapid and sensitive method for detecting trace CEF residues in food samples is still challenging. Herein, we report preparation of an amide and carboxyl groups dual-functionalized core-shelled magnetic microporous organic network MMON-COOH-2CONH for efficient magnetic solid-phase extraction (MSPE) of CEFs from milk powder samples. Under optimal conditions, the established MMON-COOH-2CONH-MSPE-HPLC-UV method owns wide linear range (3-10000 µg kg-1), low limits of detection (1-3 µg kg-1), large enrichment factors (93.9-99.4), low adsorbent consumption (3 mg), and short extraction time (6 min). Synergistic extraction mechanisms of ionic bonding, hydrogen bonding, π-π, and hydrophobic interactions were elucidated by both theoretical density functional theory calculations and experimental data. This study confirms that preparation of dual-functionalized MMONs and introduction of ionic groups are feasible to promote MMONs application in sample pretreatment.

[Cutting scheme and clinical application effects of ultrathin thoracodorsal artery perforator flap assisted by color Doppler ultrasound]

Objective: To explore the cutting scheme and clinical application effects of ultrathin thoracodorsal artery perforator flap assisted by color Doppler ultrasound. Methods: This study was a retrospective historical control study. From February 2017 to October 2019, 20 patients who were admitted to the Third Department of Orthopedics of Xingtai General Hospital of North China Medical and Health Group (hereinafter referred to as our department), met the inclusion criteria, and underwent repair of skin and soft tissue defects of extremities with ultrathin thoracodorsal artery perforator flap designed and harvested based on the surgeon's clinical experience were selected as control group, including 16 males and 4 females, aged (37±5) years. From November 2019 to December 2022, 21 patients who were admitted to our department, met the inclusion criteria, and underwent repair of skin and soft tissue defects of extremities with ultrathin thoracodorsal artery perforator flap designed and harvested under the assistance of color Doppler ultrasound were selected as ultrasound-assisted group, including 15 males and 6 females, aged (38±6) years. After debridement, the area of skin and soft tissue defects of extremities ranged 5.0 cm×4.0 cm to 19.0 cm×8.0 cm, and the area of thoracodorsal artery perforator flaps ranged 6.0 cm×5.0 cm to 20.0 cm×9.0 cm. The wounds in flap donor sites were closed directly. For patients in ultrasound-assisted group, the time and cost required for color Doppler ultrasound examination were recorded, and the number, type, and location of thoracodorsal artery perforator vessels detected by preoperative color Doppler ultrasound were compared with those of intraoperative actual detection. The time required for complete flap harvest of patients in 2 groups was recorded. On postoperative day (POD) 1, 3, 5, 7, and 14, the blood perfusion of flaps in the 2 groups of patients was assessed using a flap perfusion assessment scale. On POD 14, flap survival of patients in 2 groups was observed, and the percentage of flap survival area was calculated. In postoperative 6 months, satisfaction of patients with the treatment outcome in the 2 groups was assessed using 5-grade Likert scale, and the satisfaction rate was calculated. Results: For patients in ultrasound-assisted group, the time required for preoperative color Doppler ultrasound examination was (10.5±2.3) min, and the cost was 120 yuan; 21 thoracodorsal artery perforator vessels were detected and marked using preoperative color Doppler ultrasound, including 8 (38.10%) type 1 perforator vessels, 10 (47.62%) type 2 perforator vessels, and 3 (14.29%) type 3 perforator vessels; the number, type, and location of thoracodorsal artery perforator vessels detected preoperatively were consistent with those detected intraoperatively. The time required for complete flap harvest of patients in ultrasound-assisted group was (41±10) min, which was significantly shorter than (63±12) min in control group (t=6.32, P<0.05). On POD 1, 3, 5, 7, and 14, the blood perfusion scores of flaps of patients in ultrasound-assisted group were significantly better than those in control group (with t values of 6.67, 7.48, 8.03, 8.75, and 7.99, respectively P<0.05). On POD 14, only one patient in ultrasound-assisted group had partial flap necrosis and 6 patients in control group had complete or partial necrosis of the flap; the percentage of flap survival area of patients in ultrasound-assisted group was (99±8)%, which was significantly higher than (87±8)% in control group (t=4.57, P<0.05). In postoperative 6 months, there was no significant difference in the satisfaction rate of patients with the treatment outcome between the two groups (P>0.05). Conclusions: Preoperative color Doppler ultrasound is highly accurate in detecting the number, type, and location of perforator vessels. The cutting scheme of ultrathin thoracodorsal artery perforator flaps can be designed according to the different types of perforator vessels, with shorted flap cutting time and improved flap survival rate.

Construction of an ultra-small hydrazone-linked covalent organic polymer for selective fluorescent detection of ferric ion in aqueous solution

A novel ultra-small hydrazone-linked covalent organic polymer (UHCOP) was synthesized based on the Schiff-base reaction between 2,4,6-trihydroxy-1,3,5-benzenetricarbaldehyde and 1,4-benzenedicarbohydrazide at room temperature and utilized as a sensitive fluorescent sensor for rapid (<2 min) and selective detection of Fe³⁺ in aqueous solution. The prepared UHCOP displayed ultra-small size with the diameter of 7.98 ± 0.97 nm and gave a stable fluorescent emission at 510 nm. UHCOP exhibited good sensitivity and highly selectivity towards Fe³⁺. The coordination interaction between UHCOP and Fe³⁺ resulted in the obviously aggregation-caused quenching response of UHCOP. The linear range was from 5.0 μM to 1.4 mM (R² = 0.999) with the detection limit of 2.5 μM. Finally, UHCOP has been successfully applied in the detection of Fe³⁺ in real water samples, proving the fabricated UHCOP is promising as a sensitive fluorescent sensor for selective detection of Fe³⁺ in aqueous solution.

Thiol-Ene Click Synthesis of Phenylboronic Acid-Functionalized Covalent Organic Framework for Selective Catechol Removal from Aqueous Medium

We report a thiol-ene click strategy for the preparation of a novel phenylboronic acid-functionalized covalent organic framework (COF) for selective removal of catechol in aqueous solution. Vinyl-functionalized 2,5-diallyloxyterephthalaldehyde (Da-V) was prepared as a building ligand. Da-V was then condensed with 1,3,5-tris(4-aminophenyl)benzene (Tab) to give a vinyl-functionalized COF DhaTab-V. Subsequently, 4-mercaptophenylboronic acid (4-MPBA) was covalently linked on DhaTab-V via thiol-ene click reaction to give phenylboronic acid-functionalized COF DhaTab-PBA. The adsorption isotherms, energetics and kinetics, and reusability of DhaTab-PBA for the adsorption and removal of catechol from aqueous solution were investigated in detail. This phenylboronic acid-functionalized COF is promising as sorbent for selective removal of catechol from aqueous medium with large adsorption capacity and good reusability.

Determination of steroid estrogens in wastewater treatment plant of a controceptives producing factory

Steroid estrogens such as estrone (E1), 17beta-estradiol (E2), estriol (E3), and 17alpha-ethynylestradiol (EE2) have been suspected to be the main contaminants, which can affect the endocrine system of animals. Many authors have investigated these chemicals in the domestic wastewater treatment plants (WTP). However, wastewater from industries producing steroid contraceptives has not got ample attention. From the environmental point of view, the four steroids are very significant because even very low concentrations (ng/L) can cause reproductive disturbances in human, livestock and wildlife. The main purpose of the present investigation was to develop an analytical method for the determination of the four steroid estrogens present in WTP of a pharmacy factory, mainly producing contraceptive medicine in Beijing, China. Analysis was performed by solid-phase extraction (SPE) system and liquid chromatography combined with tandem mass spectrometry (LC/MS/MS). The average recoveries from effluent samples ranged from 88% to 103% and the precision of the method ranged from 9% to 4%. Based on 0.5-L wastewater samples, the limit of quantification (LOQ) was determined at 0.7 ng/L for E1, 0.8 for E2, 0.9 ng/L for E3, and 0.5 ng/L for EE2 in influent, and 1.0 ng/L for E2 and EE2, and 2.0 ng/L for E1 and E3 in effluent. In the influent samples, average concentrations of 80, 85, 73 and 155 ng/L were determined for E1, E2, E3 and EE2, respectively, showing that they were removed in this WTP to the extent of 79, 73, 85 and 67%, respectively.