A novel 3D Cd(ii) coordination polymer generated via in situ ligand synthesis involving C–O ester bond formation

A novel 3D Cd(ii) coordination polymer {[Cd(ddpa)(2,2′-bpy)]·H₂O}_n (1) (H₂ddpa = 5,10-dioxo-5,10-dihydro-4,9-dioxapyrene-2,7-dicarboxylic acid, 2,2′-bpy = 2,2′-bipyridine) is hydrothermally synthesized in situ, and the influencing factors and mechanism for the in situ reaction are briefly discussed. The synthesis of 1 requires the formation of a new C–O ester bond. This current study confirms that metal ions and N-donor ligands play important roles in the domination of the in situ ligand from 6,6′-dinitro-2,2′,4,4′-biphenyltetracarboxylic acid (H₄dbta). Furthermore, the structure, thermal stability and photoluminescent property of 1 are also investigated.

A 3D Cd(ii) coordination polymer comprising ligand molecules not included in the original reaction mixtures but instead formed via in situ ligand synthesis involving a C–O ester bond.     

Characterizing the binding interaction of astilbin with bovine serum albumin: a spectroscopic study in combination with molecular docking technology

Astilbin (ASN) is a flavonoid compound isolated from the rhizome of Smilax china L. (Smilacaceae). It has many bioactivities, such as selective immunosuppression, antioxidant, anti-hepatic injury, etc., and is widely used in traditional Chinese medical treatments. The interaction of ASN with bovine serum albumin (BSA) was studied in a physiological buffer (pH = 7.40) using multi-spectroscopic techniques in combination with molecular docking methods. UV-vis absorption measurements proved that a ASN–BSA complex could be formed. Fluorescence data revealed that ASN could strongly quench the intrinsic fluorescence of BSA in terms of a static quenching procedure. The process of binding was spontaneous and the binding occurred mainly through hydrogen bonding and van der Waals forces. The distance r between donor (BSA) and acceptor (ASN) was calculated to be 4.80 nm based on Förster''s non-radiative energy transfer theory. The binding constant (K_a = 7.31 × 10⁴ mol L⁻¹) and the number of binding sites (n ≈ 1) at 298 K suggested that ASN only occupied one site in BSA with high affinity. Moreover, the results of molecular docking indicated that ASN was more likely to be located in site I (sub-domain IIA) of BSA. The results of synchronous fluorescence and three-dimensional fluorescence spectra showed that ASN induced conformational changes of BSA. The findings would be beneficial for research on the transportation, distribution and some important bioactivities of ASN in the human body.

The interaction of astilbin with bovine serum albumin was confirmed by multi-spectroscopic techniques and molecular docking methods.     

A coumarin Schiff's base two-photon fluorescent probe for hypochlorite in living cells and zebrafish

Selective and sensitive fluorescent probes for ClO⁻ are desirable due to the importance of ClO⁻ in biological processes. Here, a coumarin Schiff''s base, compound 1, has been developed and successfully used as a one- and two-photon fluorescent probe for ClO⁻ with high selectivity. This probe can recognize ClO⁻ with obvious color change from yellow-green to colorless and green to blue fluorescence emission, which can be observed by the naked eye. The properties of low cytotoxicity and good cell permeability allow it to be used for ClO⁻ detection in living cells and zebrafish by both one- and two-photon microscopy imaging. All these results indicate that the compound is a sensitive probe with potential for analysis of ClO⁻ in biological samples. The mechanism by which probe 1 recognizes ClO⁻ is possibly nucleophilic addition followed by hydrolysis.

A coumarin Schiff''s base compound can selectively recognize ClO⁻ and can be successfully applied to the detection of ClO⁻ in living cells and zebrafish by one- and two-photon fluorescence modes.     

Laser induced graphitization of PAN-based carbon fibers

Laser induced graphitization of polyacrylonitrile-based carbon fibers (CFs) was carried out in a self-designed furnace with a CO₂ laser source. The microstructures combined with mechanical properties of the irradiated CFs were measured by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and single filament tensile test, respectively. The results exhibited that the hierarchical structures of CFs showed different responses to the CO₂ laser. After laser graphitization, the surface and cross-section structure were characterized by Raman spectroscopy. As the power density increased, a profound increase of graphitization degree happened and obvious skin-core structures were observed. Furthermore, the results of XPS measurements indicated that the irradiated CFs showed more conjugated structures. For crystallite structure, the interlayer spacing of the (002) lattice decreased and the thickness of crystallite increased after graphitization. The size of the (002) lattice parallel to the fiber axis changed slightly. The surface morphology was also investigated by SEM, sheet structures and particles could be observed on the surface of CFs. This was attributed to fast energy addition of laser and the characteristics of the material. Further HRTEM investigation revealed that the sheet structure is multilayered graphene. The Young''s modulus of irradiated fibers showed obvious improvements compared to that of as-received ones.

A new method based on laser technique is proposed to graphitize PAN-based CFs.     

Kinetic model of biomass hydrolysis by a polysulfone membrane with chemically linked acidic ionic liquids via catalytic reactor

A novel catalytic membrane was prepared from polysulfone powders covalently linked with acidic ionic liquids (PSF-ILs), as a heterogeneous catalyst to produce reducing sugar for biomass inulin hydrolysis in a catalytic membrane reactor. However, a complete kinetic model describing the relationship between catalyst physical properties and hydrolysis performance is lacking. The present work attempts to build a hydrolysis kinetic model for the relationship between the conversion and the structure of the PSF-ILs membrane (such as membrane thickness, pore size, porosity and specific surface area). The reaction parameters, such as the reaction time, reaction temperature as well as the nature of the catalyst were of crucial importance in terms of optimal conversion of the biomass inulin to reducing sugar or platform chemicals. The results showed that the structure of the PSF-ILs membrane has a significant effect on its catalytic performance. The PSF-ILs membrane with the best catalytic performance was selected and the maximum TRS yields were up to 100% after two rounds of inulin hydrolysis. The conversions obtained from the established model are in good agreement with the experimental data. Understanding the structure–property relationship of the PSF-ILs membrane will be helpful in designing the physical structure of the membrane to improve its catalytic activity and reusability. Therefore, it is a type of green catalyst with potential application prospects in many catalysis fields.

The PSF-ILs membrane exhibits higher catalytic performance and a kinetic model between conversion and membrane structure was established successfully.     

Alginate based antimicrobial hydrogels formed by integrating Diels–Alder “click chemistry” and the thiol–ene reaction

In recent years medical devices manufacturers have been looking for antimicrobial coatings which are biocompatible and non-toxic for a wide range of medical devices. The demand for these antimicrobial coatings has increased significantly, owing to the increased incidence of hospital-associated infections (HAIs). Hydrogels have been widely used in biomedical applications due to their hydrophilicity, biodegradability, non-toxicity and biocompatibility. In this work, sodium alginate (SA) based antibacterial hydrogels SA/PEG–HHC10 were designed and prepared by combining Diels–Alder (DA) click chemistry and the thiol–ene reaction. The hydrogels were first prepared using DA click chemistry with good mechanical strength, then the cysteine-terminated antimicrobial peptide HHC10–CYS (HHC10) was grafted into the hydrogel by the thiol–ene reaction between the oxy-norbornene group and the thiol group. The results showed that the antimicrobial hydrogels had a strong antibacterial property and good biocompatibility. Therefore, the antimicrobial hydrogels have significant potential application as coatings for implantable medical devices.

In recent years medical devices manufacturers have been looking for antimicrobial coatings which are biocompatible and non-toxic for a wide range of medical devices.     

Using biomimetically mineralized collagen membranes with different surface stiffness to guide regeneration of bone defects

Because guided bone regeneration (GBR) process is pronouncedly affected by the micro‐environment in the defect, the surface stiffness of collagen membranes as a constituent part of the micro‐environment was investigated in this study. The objective of this study was to manufacture biomimetically mineralized collagen membranes with controllable surface stiffness based on biomimetic strategy and to investigate the influences of surface stiffness on GBR process. The characterization and biocompatibility of membranes were examined in vitro. The mechanical properties of membranes were evaluated on macro and micro levels using tensile test and atomic force microscope, respectively. The critical‐size cranial defect model and ectopic osteogenesis were chosen to employ their performances in vivo. The results indicated that the biomimetically mineralized collagen membranes with controllable surface stiffness were manufactured based on the biomimetic theory. The in vitro experiments showed that the mineralized collagen membrane with satisfactory surface stiffness can better promote the adhesion, proliferation, and osteogenic differentiation of mesenchymal stem cells. The membranes can perform excellently in both osteoinduction and osteoconduction, which results in effective manifestations in aspects of ectopic osteogenesis and GBR in vivo. Therefore, this biomimetically mineralized collagen membrane is a promising candidate for GBR treatment in future.     

Historically‐informed nursing: A transnational case study in China

The term ‘nurse’ (hushi—’caring scholar’) did not enter the Chinese language until the early 20th century. Modern nursing—a fundamentally Western notion popularized by Nightingale and introduced to China in 1884—profoundly changed the way care of the sick was practiced. For 65 years, until 1949, nursing developed in China as a transnational project, with Western and Chinese influences shaping the profession of nursing in ways that linger today. Co‐authored by Chinese, Canadian, and American nurses, this paper examines the early stages of nursing in one province of China as an exemplar of the transnational nature of nursing development. By identifying sociopolitical influences on the early development of nursing in Shandong, the authors aimed not only to contribute to the nascent body of knowledge on China nursing history, but also to heighten readers’ sensitivity to the existence of historical echoes, residue, and resonances in their own nursing practices. Tracing current issues, values, or practices back to their roots provides context and helps us to better understand the present. Whether we are aware of the details or not, the gestalt of nursing practice in a particular place has been shaped by its history—including in Shandong province in China.     

Interferon-based treatment is superior to nucleos(t)ide analog in reducing HBV-related hepatocellular carcinoma for chronic hepatitis B patients at high risk

Background: The effect of nucleos(t)ide analogs (NAs) versus interferon (IFN) on the occurrence of hepatocellular carcinoma (HCC) in chronic hepatitis B (CHB) is controversial. We assessed whether antiviral strategy affected HCC development in CHB patients at different HCC risks.

Methods: 1112 CHB patients with antiviral therapy were included in this retrospective study. Patients treated with NAs only were classified into NAs group (n = 682) while those received IFN treatment with or without NAs were defined as IFN group (n = 430). Propensity score matching (PSM) was applied to minimize baseline differences.

Results: Totally, 31 patients developed HCC during follow-up (median 5.41 years). The cumulative HCC incidence at 10 years was significantly lower in the IFN group than NAs group (2.7% vs 8.0%, p < 0.001). Similar results were obtained in the PSM-cohort. Patients with IFN-based treatment were less likely to develop HCC than those with NAs (Hazard ratio = 0.15; 95% CI 0.04–0.66; p = 0.012). Subgroup analyses demonstrated that this superiority of IFN in reducing HCC development was obvious in patients at high- but not low-risk of HCC.

Conclusions: Reduction of HCC development was more significant in CHB patients at higher HCC risk with IFN-based therapy than NAs treatment.