Recent advances and challenges in materials for 3D bioprinting

3D bioprinting has been developed as a promising technology in a wide variety of biomedical applications. However, the successful implementation of bioprinting is still heavily restricted by the relatively narrow range of printable and biocompatible materials. Recently, many comprehensive reviews of the main bioprinting methods, commonly used bioprinting materials and the trending bioprinting applications have been carried out. In this review, we focused on the trends in the development of materials for 3D bioprinting. The significance and recent advances of ECM-based materials, multi-material and stimuli-responsive materials for bioprinting were summarized successively. Moreover, the challenges in current studies and future perspectives of materials for 3D bioprinting were discussed.     

Characterization of new Pt(IV)–thiazole complexes: Analytical,spectral, molecular modeling and molecular docking studies and applications in two opposing pathways

New thiazole derivatives were synthesized and fully characterized, then coordinated with PtCl₄ salt. Also, the newly synthesized Pt(IV) complexes were investigated analytically (elemental and thermogravimetric analyses), spectrally (infrared, UV–visible, mass, ¹H NMR, ¹³C NMR, X‐ray diffraction) as well as theoretically (kinetics, modeling and docking). The data extracted led to the establishment of the best chemical and structural forms. Octahedral geometry was the only formula proposed for all complexes, which is favorable for d⁶ systems. The molecular ion peaks from mass spectral analysis coincide with all analytical data, confirming the molecular formula proposed. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) allowed discrimination of features between crystalline particles and other amorphous morphology. By applying Gaussian09 as well as HyperChem 8.2 programs, the best structural forms were obtained, as well as computed significant parameters. Computed parameters such as softness, hardness, surface area and reactivity led us towards application in two opposing pathways: tumor inhibition and oxidation activation. The catalytic oxidation for CO was conducted over PtO₂, which was yielded from calcination of the most reactive complex. The success of catalytic role for synthesized PtO₂ was due to its particulate size and surface morphology, which were estimated from XRD patterns and SEM images, respectively. The antitumor activity was tested versus HCT‐116 and HepG‐2 cell lines. Mild toxicity was recorded for two of the derivatives and their corresponding complexes. This degree of toxicity is more favorable in most cases, due to exclusion of serious side effects, which is coherently attached with known antitumor drugs.     

国家层面创新能力的评价

 综述了创新、创新监测与评价的研究进展，辨析了国家创新能力、创新型国家和科技强国的内涵特征，分析了中国创新能力在世界上的相对位置，探讨了建设科技强国的经验及启示。     

Dinuclear gold (I)-di-N-heterocyclic carbene complexes: syntheses,structure, density functional theory calculation and photoluminescence study

The synthesis and characterizations for a series of dinuclear gold (I)-di-NHC complexes, 1–8 through the trans-metalation method of their respective silver (I)-di-NHC complexes, i–viii are reported (where NHC = N-heterocyclic carbene). The successful complexation of a series of unusual non-symmetrical and symmetrical di-NHC ligands, 3,3'-(ethane-1,2-diyl)-1-alkylbenzimidazolium-1'-butylbenzimidazolium (with alkyl = methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, benzyl) with the gold (I) ions are suggested by elemental analysis, Fourier transform-infrared, ¹H- and ¹³C-NMR data. The ¹³C-NMR spectra of 1–8 show a singlet sharp peak in the range of 190.00–192.00 ppm, indicating the presence of a carbene carbon that bonded to the gold (I) ion. From single crystal X-ray diffraction data, the structure of complex 6 with the formula of [di-NHC-Au (I)]₂·2PF₆ is obtained [where NHC = 3,3'-(ethane-1,2-diyl)-1-hexylbenzimidazolium-1'-butylbenzimidazolium]. The photophysical study in solid state of 6 displays an intense photoluminescence with a strong emission maxima, λ_em = 480 nm, upon excitation at 340 nm at room temperature. Interestingly, the emission maximum at 77 K shows a structural character with a strong peak at 410 nm, a medium at 433 nm and a weak at 387 nm, accompanied by a tail band to about 500 nm.     

New organoruthenium metallates containing ferrocenecarboxalidine thiosemicarbazones and their nucleic acid/albumin binding and in vitro cytotoxicity

A string of four new hetero binuclear Ru(III) complexes of ferrocenecarboxaldehyde-4(N)-substituted thiosemicarbazones were synthesized and characterized by various spectral (infrared, ultraviolet–visible, Electron Paramagnetic Resonance (EPR) and High Resolution Mass Spectrometry (HR-MS) techniques. The binding abilities of the ligands/complexes with nucleic acid (calf thymus DNA, CT-DNA) and bovine serum albumin (BSA) were analyzed by absorption and emission titration methods. The complexes exhibited better DNA binding affinity than their parent ligands. The interaction with CT-DNA was found to be intercalative and with BSA static quenching mechanism was observed. All the synthesized Ru(III) complexes were subjected to study their in vitro cytotoxicity against MCF-7 (human breast cancer) and HT-29 (human colon cancer) cell lines. Among the four complexes, complex 3 [RuCp (FF-etsc)PPh₃]Cl exhibited the highest cytotoxicity in MCF-7 cells and complex 4 [RuCp (FF-ptsc)PPh₃]Cl was the most active on HT-29 cells.     

基于炉灶热量回收的吸热装置设计

设计了一种基于炉灶热量回收的吸热装置。该装置通过将导热性能及焊接性能优良的无氧紫铜管与炉灶支架焊接成一个整体,近距离吸收炉灶火焰四周散失的热量,利用火焰散失的热量给生活用水加热,将生成的热水供日常生活使用;对出水装置进行改良,使其与加热装置形成循环结构,达到对整个系统进行保护的目的。本装置提高了对能源的利用率,减少了能源消耗,达到节能的目的。     

Preparation and Characterization of Activated Carbon from Microwave and Conventional Heated Almond Shells Using Phosphoric Acid Activation

Activated carbon production from almond shells using phosphoric acid activation agent was achieved by applying both conventional heating and microwave heating in succession. The morphology and surface properties of activated carbon were studied using thermogravimetric and differential gravimetric analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller analysis. A surface area of 1128 m²/g was achieved by optimizing the microwave power (500?W), microwave application time (15?minutes), conventional heating time (45?minutes), conventional heating temperature (500?°C), and the phosphoric acid:sample ratio (0.7:1). An adsorption capacity of methylene blue of 148?mg/g and an iodine value of 791?mg/g was obtained for the prepared activated carbon.     

Et2Zn-mediated stoichiometric C(sp)-H silylation of 1-alkynes and chlorosilanes

A first example of an Et₂Zn mediated silylation of 1-aklynes is reported. A series of functional groups are tolerated in this reaction. Mechanistic studies support Zn alkynilides as intermediates in the reaction. This reaction protocol provides a practical method for the preparation of alkynylsilanes and expands the application of organometallic zinc in organic synthesis.     

Revealing and comparing different excited-state intramolecular proton transfer processes for 3-(4-dimethylamino-phenyl)-1-(4-fluoro-2-hydroxy-phenyl)-propenone and 3-(4-dimethylamino-phenyl)-1-(4-fluoro-2-hydroxy-phenyl)-3-hydroxy-propenon

Two novel 2′-hydroxychalcone derivatives (i.e., M1 and M2) are explored in this work. We mainly focus on investigating the effects of photoexcitation on hydrogen bonds and on the excited-state intramolecular proton transfer (ESIPT) process. On the basis of calculations of electrostatic potential surface and intramolecular interactions, we verify the formation of hydrogen bond O1 H2···O3 in both S₀ and S₁ states. Exploring the ultraviolet–visible spectra in the liquid phase, our simulated results reappear in the experimental phenomenon. Analyzing molecular geometry and infrared stretching vibrational spectra, we confirm O1 H2···O3 is strengthened for both M1 and M2 in the S₁ state. We further confirm that charge redistribution facilitates ESIPT tendency. Constructing potential energy curves, we find the ultrafast ESIPT behavior for M1, which is because of the deficiency of side hydroxyl moiety comparing with M2. This work makes a reasonable affiliation of the ESIPT mechanism for M1 and M2. We wish this paper could facilitate understanding these two novel systems and promote their applications.