New Insights into the Mechanism of Enhanced Performance of Li[Ni0.8Co0.1Mn0.1]O2 with a Polyacrylic Acid-Modified Binder.

A binder is an important component in lithium-ion batteries and plays a significant role in maintaining the properties of active substances. Most studies in the field of binders have only focussed on physical properties such as bonding performance. Here, a polyacrylic acid-modified binder was designed and adapted to Li[Ni0.8Co0.1Mn0.1]O2, which enhanced the electrochemical stability of Li[Ni0.8Co0.1Mn0.1]O2 from 30.2 to 66.6% (300 cycles at 1 C). We for the first time discovered that this was caused by a chemical reaction between polyacrylic acid and the residual lithium on the surface during the cycling, which formed a lithium propionic acid coating layer and maintained the stability of the layered structure.

Hydrangea-Like CuS with Irreversible Amorphization Transition for High-Performance Sodium-Ion Storage.

Metal sulfides have been intensively investigated for efficient sodium-ion storage due to their high capacity. However, the mechanisms behind the reaction pathways and phase transformation are still unclear. Moreover, the effects of designed nanostructure on the electrochemical behaviors are rarely reported. Herein, a hydrangea-like CuS microsphere is prepared via a facile synthetic method and displays significantly enhanced rate and cycle performance. Unlike the traditional intercalation and conversion reactions, an irreversible amorphization process is evidenced and elucidated with the help of in situ high-resolution synchrotron radiation diffraction analyses, and transmission electron microscopy. The oriented (006) crystal plane growth of the primary CuS nanosheets provide more channels and adsorption sites for Na ions intercalation and the resultant low overpotential is beneficial for the amorphous Cu-S cluster, which is consistent with the density functional theory calculation. This study can offer new insights into the correlation between the atomic-scale phase transformation and macro-scale nanostructure design and open a new principle for the electrode materials' design.

Study on the interaction of an anthracycline disaccharide with DNA by spectroscopic techniques and molecular modeling.

This study was designed to examine the interaction of 4'-O-(a-L-Cladinosyl) daunorubicin (DNR-D5), a disaccharide anthracycline with calf thymus deoxyribonucleic acid (ctDNA) by UV/Vis in combination with fluorescence spectroscopy and molecular modeling techniques under physiological conditions (Britton-Robinson buffer solutions, pH = 7.4). By the analysis of UV/Vis spectrum, it was observed that upon binding to ctDNA the anthraquinone chromophore of DNR-D5 could slide into the base pairs. Moreover, the large binding constant indicated DNR-D5 had a high affinity with ctDNA. At the same time, fluorescence spectra suggested that the quenching mechanism of the interaction of DNR-D5 to ctDNA was a static quenching type. The binding constants between DNR-D5 and ctDNA were calculated based on fluorescence quenching data at different temperatures. The negative ∆G implied that the binding process was spontaneous, and negative ∆H and negative ΔS suggested that hydrogen bonding force most likely played a major role in the binding of DNR-D5 to ctDNA. Moreover, the results obtained from molecular docking corroborate the experimental results obtained from spectroscopic investigations.

[Study on the interaction between DNR-D3 (daunorubicin derivative)and ctDNA by spectroscopic methods].

The interaction of DNR-D3 (daunorubicin derivative) synthesized in our laboratory with ctDNA was investigated by UV spectrum and fluorescence spectrum under physiological conditions (pH 7.4) for the first time. The red shifts and hypochromicities were observed from the absorption titration experiments. These results suggest that DNR-D3 was intercalated into the DNA base pairs. Through the fluorescence quenching data measured at different temperatures (20 degrees C, 30 degrees C and 37 degrees C), it is known that the quenching mechanism of fluorescence of DNR-D3 by ctDNA is a static quenching type. On the other hand, the binding constant, the number of binding sites and thermodynamic parameters were also obtained. These data also indicate that the binding mode of the interaction between DNR-D3 and ctDNA is intercalation. Additionally, the types of interaction force are mainly hydrogen bonding and electrostatic interaction, and the binding is exothermic enthalpy-entropy cooperative driven process. When the degree of fluorescence quenching of DNR-D3 is 50%, the ratio of the molar concentration of DNR-D3 to ctDNA is 7/25, which indicates that the DNR-D3 anthracycline was intercalated into the DNA base pairs and that DNR-D3 showed a strong anti-cancer activity. DNR-D3 is expected to become one of the drug candidates from our investigations.

[Studies on the reaction of norfloxacin with ovalbumin].

The interaction between norfloxacin (NRF) and ovalbumin (OVA) was studied by fluorescence and absorption spectroscopy. The binding constants and the binding sites were measured by fluorescence quenching method. It was found that the emission peak of OVA was positioned at 338 nm. When the norfloxacin was added into OVA solution gradually, the intensity of 338 nm emission peak of OVA decreased obviously and moved towards long wavelength. The experiment demonstrated that the higher the temperature, the lower the slopes of quenching curves of OVA in the presence of different amounts of NRF. It was confirmed that the combination of NRF with OVA is a single static quenching process. With the increase in the pH of the solution, the quenching efficiency decreased in the binding. From thermodynamic parameters, it can be judged that the binding power between OVA and NRF is electrostatic effect and H-bond formation. The UV-Vis absorption spectra of OVA in the presence of NRF show that the conformation of OVA changed.

Study on the binding of fluoride, bromide and iodide to ovalbumin by using ion-selective electrodes.

The interactions of F(-), Br(-) and I(-) with ovalbumin (OVA) were studied in acetate buffers of pH 5.68, at 288.15 K, 298.15 K and 308.15 K, using ion-selective electrodes. The data for the ion-protein systems were treated according to the Klotz equation, and the number of binding sites and the binding constants were determined. It is shown that the binding sites of F(-) on OVA molecule are more than those of Br(-) and I(-), and that the binding sites of F(-), Br(-) and I(-) on OVA molecule decreases with increasing temperature. At the same time, our studies indicate that the binding constants for the interactions of F(-), Br(-) and I(-) with OVA show a same trend: They decrease as temperature increases. These were reasonably interpreted with the structural and thermodynamic factors. The thermodynamic functions (DeltaG(), DeltaH(), DeltaS()) at different temperatures were calculated with thermodynamic equations, and the enthalpy change for the interactions were also determined by isothermal titration calorimetry (ITC) at 298.15 K, which indicate that the interactions of F(-), Br(-) and I(-) with OVA are mainly electrostatic interaction. Simultaneously, there are also partial desolvation of solutes and solvent reorganization effect.

[Progress in study of secondary structure of denaturized protein by FTIR].

Protein is one of the most important living matters, and researches relatedto it have interested so many scientific workers. The secondary structure of protein plays a crucial role in maintaining protein's physiological activity. With the development of technology and the improvement of research technique, there are more and more in-depth studies on protein's microstructure. In recent years, many research works in this field have been done with different kinds of physical and chemical methods and Fourier transform infrared spectroscopy(FTIR)holds an unshaken position due to its unique superiority. The present paper is a general review of the related studies all over the world, and the assignments of the major infrared absorption bands of denaturized protein are introduced, and the spectroscopic features and the analytical methods are mainly reviewed.