Highly Emissive and Robust Cd-Based MOF with an Unprecedented Topology for Tetracycline Sensing.

Herein, an unprecedented cadmium-based metal-organic framework (JNU-106) fabricated by utilizing pyrazole-functionalized tetraphenylethylene ligands (Py-TPE) and rod-shaped secondary building units is reported, possessing a new (3,3,3,6,6,8)-connected topological network. Thanks to the ingeniously designed intramolecular charge transfer behavior, which originates from the congruent coplanarity between Py and TPE, JNU-106 exhibits intense green luminescence with a quantum yield increased by 1.5 times. The phenomenon of remarkable fluorescence quenching of JNU-106 reveals that it possesses extremely high anti-interference performance, superior sensitivity, and dedicated selectivity toward tetracycline antibiotics (TCAs) in aqueous solutions, which are comparable to those of the state-of-the-art porous sensing compounds. Taking the theoretical calculations and experimental results into account, the luminescence quenching is mainly attributed to the internal filtration effect and the static quenching effect. Considering the portable and rapid performance of JNU-106-based testing strips for sensing TCAs, the fabricated JNU-106 provides an alternative for ecological monitoring and environmental governance.

Development of a ZIF-91-Porous-Liquid-Based Composite Hydrogel Dressing System for Diabetic Wound Healing.

Porous metal-organic framework (MOF) liquids with permanent porosity, good fluidity, and fine dispersion attract broad attention in catalysis, transportation, gas storage, and chemical separations. Yet, the design and synthesis of porous MOF liquids for drug delivery remain less explored. Herein, a simple and general strategy is reported to prepare ZIF-91 porous liquid (ZIF-91-PL) via surface modification and ion exchange. The cationic nature of ZIF-91-PL not only renders it antibacterial but also with high curcumin loading capacity and sustained release. More importantly, the acrylate group on the grafted side chain of ZIF-91-PL makes it feasible to crosslink with modified gelatin through light curing, and the obtained hydrogel shows a significantly improved healing effect on the wound of diabetes. This work demonstrates for the first time, a MOF-based porous liquid for drug delivery, and the further fabrication of composite hydrogel may have potential applications in biomedical science.

Mixed-Linker Isoreticular Zn(II) Metal-Organic Frameworks as Brønsted Acid-Base Bifunctional Catalysts for Knoevenagel Condensation Reactions.

Multicomponent metal-organic frameworks (MOFs) have received an increasing amount of attention due to their potential to produce new topologies, pore metrics, and functionalities compared to MOFs with a single metal cluster and one organic linker. Herein, five isoreticular Zn MOFs were obtained by mixing two types of linear ditopic linkers in a one-pot solvothermal synthesis. Interestingly, in the resulting Zn MOFs a six-connected cyclic trinuclear Zn(II) cluster and an eight-connected linear trinuclear Zn(II) cluster coexist, leading to an uncommon (6,8)-connected network. Catalytic activities toward the solvent-free Knoevenagel reactions were observed for all of these MOFs. Further experimental and computational studies suggest that they are Brønsted acid-base bifunctional catalysts. Through chemical modifications of dicarboxylate ligands, including their aromatic backbones and substituents, we have successfully implemented reticular chemistry for the modulations of pore sizes, surface areas, and catalytic performances in a series of four-component isoreticular MOFs.

Building a Pyrazole-Benzothiadiazole-Pyrazole Photosensitizer into Metal-Organic Frameworks for Photocatalytic Aerobic Oxidation.

Charge separation plays a crucial role in regulating photochemical properties and therefore warrants consideration in designing photocatalysts. Metal-organic frameworks (MOFs) are emerging as promising candidates for heterogeneous photocatalysis due to their structural designability and tunability of photon absorption. Herein, we report the design of a pyrazole-benzothiadiazole-pyrazole organic molecule bearing a donor-acceptor-donor conjugated π-system for fast charge separation. Further attempts to integrate such a photosensitizer into MOFs afford a more effective heterogeneous photocatalyst (JNU-204). Under visible-light irradiation, three aerobic oxidation reactions involving different oxygenation pathways were achieved on JNU-204. Recycling experiments were conducted to demonstrate the stability and reusability of JNU-204 as a robust heterogeneous photocatalyst. Furthermore, we illustrate its applications in the facile synthesis of pyrrolo[2,1-a]isoquinoline-containing heterocycles, core skeletons of a family of marine natural products. JNU-204 is an exemplary MOF platform with good photon absorption, suitable band gap, fast charge separation, and extraordinary chemical stability for proceeding with aerobic oxidation reactions under visible-light irradiation.

Oxidative stress mediated decrement of spinal endomorphin-2 contributes to lumbar disc herniation sciatica in rats.

Increasing evidence supported that oxidative stress induced by herniated lumbar disc played important role in the formation of lumbar disc herniation sciatica (LDHS), however, the neural mechanisms underlying LDHS need further clarification. Endomorphin-2 (EM2) is the endogenous ligand for mu-opioid receptor (MOR), and there is increasing evidence implicating the involvement of spinal EM2 in neuropathic pain. In this study, using an nucleus pulposus implantation induced LDHS rat model that displayed obvious mechanical allodynia, it was found that the expression of EM2 in dorsal root ganglion (DRG) and spinal cord was significantly decreased. It was further found that oxidative stress in DRG and spinal cord was significantly increased in LDHS rats, and the reduction of EM2 in DRG and spinal cord was determined by oxidative stress dominated increment of dipeptidylpeptidase IV activity. A systemic treatment with antioxidant could prevent the forming of mechanical allodynia in LDHS rats. In addition, MOR expression in DRG and spinal cord remained unchanged in LDHS rats. Intrathecal injection of MOR antagonist promoted pain behavior in LDHS rats, and the analgesic effect of intrathecal injection of EM2 was stronger than that of endomorphin-1 and morphine. Taken together, our findings suggest that oxidative stress mediated decrement of EM2 in DRG and spinal cord causes the loss of endogenous analgesic effects and enhances the pain sensation of LDHS.

Pulmonary artery trunk enlargement on admission as a predictor of mortality in in-hospital patients with COVID-19.

PURPOSE: To describe the prognostic value of pulmonary artery (PA) trunk enlargement on the admission of in-hospital patients with severe COVID-19 infection by unenhanced CT image. MATERIALS AND METHODS: In-hospital patients confirmed COVID-19 from January 18, 2020, to March 7, 2020, were retrospectively enrolled. PA trunk diameters on admission and death events were collected to calculate the optimum cutoff using a receiver operating characteristic curve. According to the cutoff, the subjects on admission were divided into two groups. Then the in-hospital various parameters were compared between the two groups to assess the predictive value of PA trunk diameter. RESULTS: In the 180 enrolled in-hospital patients (46.99 ± 14.95 years; 93 (51.7%) female, 14 patients (7.8%) died during their hospitalization. The optimum cutoff PA trunk diameter to predict in-hospital mortality was > 29 mm with a sensitivity of 92.59% and a specificity of 91.11%. Kaplan-Meier survival curves for PA trunk diameter on admission showed that a PA trunk diameter > 29 mm was a significant predictor of subsequent death (log-rank < 0.001, median survival time of PA > 29 mm was 28 days). CONCLUSION: PA trunk enlargement can be a useful predictive factor for distinguishing between mild and severe COVID-19 disease progression.

[The protective effect of exenatide on the renal injury in diabetic rats].

OBJECTIVE: To investigate the protective effect of exenatide (Ex) on the renal injury in streptozotocin-induced diabetic rats. METHODS: Sprague-Dawley rats were randomly divided into 2 groups:normal control group (NC group, n=8) and model group. Model group was injected with low dose of streptozotocin (30 mg·kg-1) after the rats were fed with high fat and high glucose diet for 4 weeks. Seventy-two hours later, rats of blood glucose level ≥ 16.7 mmol·L-1 were divided into diabetes mellitus group (DM, n=10) and two exenatide-treated groups (Ex groups,3 or 6µg·kg-1, n=8). Ex groups subcutaneously injected with exenatide for 12 weeks, but NC group and DM group were injected with the same volume of solvent. Changes in glycolipid metabolism and renal function such as serum creatinine (Scr), urine creatinine (Ucr), blood urea nitrogen (BUN), 24 hour urine micro-albumin (24 h UMA)in the 4 groups of rats were determined and creatinine clearance rate (Ccr) were calculated. Renal oxidative stress parameters such as superoxide dismutase (SOD), malondialdehyde(MDA), glutathione per-oxidase (GSH-Px) were measured. Hematoxylin-eosin (HE) staining was used to examine pathological morphology in the renal tissues and ELISA was performed to determine the level of advanced glycation end products(AGEs), the glycosylation end product in renal tissues. RESULTS: Compared to the DM group,glycolipid metabolic abnormalities in the exenatide-treated groups were significantly ameliorated with lower levels of blood glucose,HbAlc, cholesterol and triglyceride (P < 0.05). The renal function index was markedly improved (P < 0.05) with Ccr reduced, indicating a high glomerular filtration status. Meanwhile, exenatide treatment improved the diabetes-induced pathological changes in renal morphology, substantially increased the activities of SOD and GSH-Px, and reduced the levels of MDA and AGEs. CONCLUSIONS: Exe-natide has the renal protective effect probably by the mechanisms of inhibition of AGEs production and reduction of oxidative stress in the renal tissues of diabetic rats.