Powering the future: A comprehensive review on calcium-ion batteries

Due to concerns regarding the future availability,cost,and safety of lithium in Li-ion batteries(LIBs),researchers are exploring alternative chemistries such as Na-ion,Li-S,Li-air,and multivalent ion technologies.Multivalent ion technologies,which utilize divalent or trivalent ions,like Mg^(2+),Ca^(2+),and Al^(3+),show promise in achieving greater energy densities than LIBs due to their ability to deposit uniformly on anodes and intercalate into cathodes.While magnesium-ion batteries(MIBs) have been the primary area of research for multivalent ion batteries,the cost-effectiveness and abundance of calcium have sparked a growing interest in calcium-ion batteries(CIBs) in recent years.Compared to LIBs,CIBs have the potential to provide longer cycle life,enhanced safety,and increased energy densities.However,the development of CIBs comes with several challenges,such as finding suitable electrode and electrolyte materials that ensure the stability and safety of the battery.The primary hurdle in CIBs lies in the plating/stripping process.There is a significant hindrance preventing the occurrence of plating/stripping in CIBs,which lies in the formation of a passive layer resulting from the decomposition of the electrolyte.The objective of this article is to examine the advancements made in CIBs.Additionally,it aims to comprehensively assess the mechanisms and materials employed in various battery components,as well as the obstacles encountered in CIBs.This includes recent advancements in electrode materials,electrolytes,cell configurations,and the challenges and opportunities for enhancing the performance and commercial viability of CIBs.

Synthesis of N-methylene phosphonic chitosan(NMPCS)and its potential as gene carder

N-Methylene phosphonic chitosan （NMPCS）, an amphiphilic macromolecule with powerful chelating ability of Ca^2＋ ions, was synthesized and characterized. The physicochernical properties of NMPCS and the interactions between NMPCS and plasmid DNA were investigated by FTIR, ^13C NMR, X-ray, agarose gel electrophoresis retardation assay, atomic force microscopy （AFM） and circular dichroism （CD）. The results suggest that at charge ratio 2：1 or above, DNA could be completely entrapped and spherical complexes with mean size of 80-210 nm were formed. Taking HeLa as host cell, luciferase expression mediated by NMPCS improved about 100 times compared to the expression mediated by chitosan.

A Novel Method for Modification of SMPU by Micro-phase Separation Promoters

A novel method of controlling the shape memory properties of shape memory polyurethane （SMPU） by addition of micro-phase separation promoters including 1-octadecanol （ODO） and liquid paraffin （LP） is reported. The results indicate that the strain recovery temperature and the strain modulus rate （Eg/Er） were increased significantly with addition of small amount of micro-phase separation promoters. Thus it can increase the shape memory fixity rate and other shape memory behaviors of SMPU.

SURFACE OF GELATIN MODIFIED POLY(L-LACTIC ACID)FILM

In this paper, the surface structure of poly(L-lactic acid) (PLLA) film modified with gelatin was investigated. ThePLLA film specimens were treated directly with aqueous alkali solution to provide their surfaces with carboxyl groups, sothat these functional groups could become the reactive sites for gelatin immobilization. The functional groups of the PLLAfilms were identified by ATR-FTIR spectra and XPS spectra, the changes in surface morphology were observed by usingenvironmental scanning electron microscopy (ESEM), and the hydrophilicity of modified PLLA films was examined bywater contact angle measurement. Experimental results showed that the gelatin was immobilized with water-solublecarbodiimide (EDC) onto the PLLA film's surfaces, and the gelatin content on the polymer surface was related to carboxylicgroup formed in the controlled hydrolysis process. Rough surfaces caused by hydrolysis will predominantly favor the adhesion and growth of cell; and the hydrophilicity of these surfaces after the modification procedure is enhanced.

PREPARATION OF POLY (LACTIC ACID)THROUGH THIONYL CHLORIDE ACTIVATED POLYCONDENSATION

A two-step process was used to synthesize the high molecular weight poly (lactic acid) using thionyl chloride as an activator for the polycondensation of prepolymer of lactic acid. The products were characterized by GPC, DSC, and 1H-NMR. Poly (L-lactic acid) (PLLA) with molecular weight Mw: 32875 was obtained when thionyl chloride was used, while low molecular weight PLLA Mw: 7350 was yielded without thionyl chloride. Effects of the concentration of thionyl chloride, polymerization time and bases on the molecular weight of poly (lactic acid) were investigated. In DSC scans the glass transition temperatures (Tg) of the resulting polymers varied from 25.3 to 57.6℃, and the Tg of poly(L-lactic acid) was higher than that of poly (D,L-lactic acid) (PDLLA). The melting points of poly (L-lactic acid) and poly (D, L-lactic acid) could not be found unless the polymers were obtained by thionyl chloride activator.

壳聚糖修饰对细胞摄入和细胞毒性的影响

目的 研究精氨酸或十六烷基修饰壳聚糖对其细胞摄入和细胞毒性的影响及作用机制。方法 用α-^32P-dATP标记质粒DNA，分别与十六烷基化壳聚糖和精氨酸修饰的壳聚糖通过复凝聚方法形成壳聚糖DNA纳米复合物。采用血管平滑肌A10细胞进行摄入测试，并用β液闪计数仪检测结果。用MTT方法对壳聚糖DNA纳米复合物的细胞毒性进行评价。结果 经^32P标记的DNA与不同修饰的壳聚糖复合所形成的纳米复合物粒径约为55．9—174．9nm，zeta电位约为1．8—10．8mV。细胞摄入实验显示通过精氨酸或十六烷基修饰的壳聚糖与DNA形成的纳米复合物更易于进入细胞。其中十六烷基化壳聚糖DNA纳米复合物（HCNC）在N／P为1：1时细胞摄入量最高，精氨酸修饰的壳聚糖DNA纳米复合物（ACNC）细胞摄人次之，与未经修饰的壳聚糖DNA纳米复合物（UCNC）相比，差异具有显著性（HCNC、ACNC比UCNC高1．3倍，P〈0．05）。细胞毒性实验显示，修饰后的壳聚糖纳米复合物的毒性远远小于商品化的细胞转染试剂Lipofectamine2000。结论 两种修饰对壳聚糖DNA纳米复合物的血管平滑肌细胞摄入有明显促进作用，其作用机制各不相同；同时其细胞毒性远小于商品化的细胞转染试剂Lipofeetamine2000。

Enhancement of transfection efficiency for HeLa cells via incorporating arginine moiety into chitosan

Arginine-rich peptides have attracted considerable attention due to their distinct internalization mechanism. It was reported that arginine and guanidino moieties were able to translocate through cell membranes and played a critical role in the process of membrane permeation. In this work, arginine was conjugated to the backbone of chitosan to form a novel chitosan derivative, arginine modified chitosan (Arg-CS). Arg-CS/DNA complexes were prepared according to the method of coacervation process. The physicochemical properties of Arg-CS and Arg-CS/DNA complexes were characterized and the transfection activity and efficiency mediated by Arg-CS/DNA complexes were investigated taking HeLa cells as target cells. Arg-CS was characterized by FTIR and 13C NMR. Arg-CS/DNA polye- lectrolyte complexes were investigated by agarose gel retardation, dynamic light scattering (DLS) and atomic force microscopy (AFM). The results revealed that the Arg-CS/DNA complexes started to form at N/P ratio of 2:1, and the size of particles varied from 100 to 180 nm. The cytotoxicity of Arg-CS and their complexes with plasmid DNA were determined by MTT assay for HeLa cells, and the results suggested that Arg-CS/DNA complexes were slightly less toxic than Arg-CS. Moreover, the derivative alone and their complexes showed significantly lower toxicity than PEI and PEI/DNA complexes, respectively. Taking HeLa cells as target cells and using pGL3-control as reporter gene, the luciferase expression mediated by Arg-CS was greatly enhanced to about 100 folds compared with the luciferase expression mediated by chitosan at different pH media. These results suggest that Arg-CS is a promising candi- date as a safe and efficient vector for gene delivery and transfection.

Incorporation of bioactive glass nanoparticles in electrospun PCL/chitosan fibers by using benign solvents

The use of bioactive glass(BG)particles as a filler for the development of composite electrospun fibers has already been widely reported and investigated.The novelty of the present research work is represented by the use of benign solvents(like acetic acid and formic acid)for electrospinning of composite fibers containing BG particles,by using a blend of PCL and chitosan.In this work,different BG particle sizes were investigated,namely nanosized and micron-sized.A preliminary investigation about the possible alteration of BG particles in the electrospinning solvents was performed using SEM analysis.The obtained composite fibers were investigated in terms of morphological,chemical and mechanical properties.An in vitro mineralization assay in simulated body fluid(SBF)was performed to investigate the capability of the composite electrospun fibers to induce the formation of hydroxycarbonate apatite(HCA).

SYNTHESIS AND CHARACTERIZATION OF NANOSTRUCTURED-SEGMENTED BLOCK COPOLYETHERAMIDE BASED ON NYLON6 AND POLY(ETHYLENE OXIDE)

Segmented block copolymer based on nylon6 （N6） and polyethylene oxide （PEO） with stochiometric ratio was synthesized via a two-step process. The first step represents end capping of N6 in the presence of adipic acid leading to carboxy terminated N6, and the second one is polycondensation of the latter product with PEO in the presence of catalyst and thermostabilizer to form a high molecular weight multi-block copolymer. Several methods were applied to characterize the synthesized copolyrner such as Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, differential thermal analysis, differential scanning calorimetry, X-ray diffraction and atomic force microscopy. The obtained results confirmed the multi-block structure for copolymer with a very high degree of micro-phase separation. Atomic force microscopy micrographs indicated that the morphology was the dispersion of high stiffness nanostructured polyamide （PA） domains in the amorphous region of PEO matrix, which can be very important in their performance for membrane processes.

Drug release behavior of chitosan/gelatin network polymer microsphere

Recently, more attention has been attracted by intelligent drug delivery systems (DDS), because the release of drug can be controlled via the system feedback responding to pathologic environment signals. Using natural polymers such as chitosan to compose this kind of pulsed DDS will be of benefit, because chitosan [.α(1→4)2-amino-2-deoxy-β-Dglucan] is one of the abundantly available polysaccharides in nature. As we know, chitosan is usually obtained by alkaline deacetylation of chitin, the principal component of shells

Microphase structures and ^(13)C NMR relaxation parameters in ultrahigh molecular weight polyethylene

The phase transformations in ultrahigh molecular weight polyethylene(UHMWPE)gel-films upon superdrawing have been studied by X-ray diffraction and high resolution solid state ^(13)C NMR.The morphological change and molecular motions in the crystalline phase,amorphous phase and interphase are dis- cussed according to the ^(13)C nuclear relaxation time(T_(1c),T_(2c)results.A brief interpretation to the three or four T_(1c)values in the crystalline phase is presented.It is found that the component with the highest T_(1c) (T_(1c)~α)plays a key role in the forming of 'Shish-Kebab' microfibril which determines the sample strength and modulus,namely,the greater the T_(1c)~α,the higher the modulus and strength of the drawn UHMWPE gel-film.These results support the 'Shish-Kebabs' model in crystalline polymers.

Study on the sound absorption mechanism in gradient water-soluble polymer solution

Attention was paid to the study on the sound absorption mechanism of water- soluble polymer during dissolving, A specially designed water-soluble polymer coating was synthesized in our lab. The sound attenuation property was measured in sound tube. The results showed that the sound attenuation of the gradient polymer solution was larger than that of the uniform. Depending on the experimental result and the theory of sound wave propagation in layered medium, a mechanism of gradient water-soluble polymer solution was developed. This mechanism can be described as follows： a water-soluble polymer coating formed a concentration gradient layer when it was dissolved in water, This gradient layer led to multiple reflection and absorption of sound. Finally the sound energy was transferred into heat.