Fast,Reversible Lithium Storage with a Sulfur/Long‐Chain‐Polysulfide Redox Couple

The cathodic reactions in Li–S batteries can be divided into two steps. Firstly, elemental sulfur is transformed into long‐chain polysulfides (S₈?Li₂S₄), which are highly soluble in the electrolyte. Next, long‐chain polysulfides undergo nucleation reaction and convert into solid‐state Li₂S₂ and Li₂S (Li₂S₄?Li₂S) by slow processes. As a result, the second‐step of the electrochemical reaction hinders the high‐rate application of Li–S batteries. In this report, the kinetics of the sulfur/long‐chain‐polysulfide redox couple (theoretical capacity=419 mA h g^?1) are experimentally demonstrated to be very fast in the Li–S system. A Li–S cell with a blended carbon interlayer retains excellent cycle stability and possesses a high percentage of active material utilization over 250 cycles at high C rates. The meso‐/micropores in the interlayer are responsible for accommodating the shuttling polysulfides and offering sufficient electrolyte accessibility. Therefore, utilizing the sulfur/long‐chain polysulfide redox couple with an efficient interlayer configuration in Li–S batteries may be a promising choice for high‐power applications.     

Substituent Effects on Oxidation‐Induced Formation of Quinone Methides from Arylboronic Ester Precursors

A series of arylboronic esters containing different aromatic substituents and various benzylic leaving groups (Br or N⁺Me₃Br^?) have been synthesized. The substituent effects on their reactivity with H₂O₂ and formation of quinone methide (QM) have been investigated. NMR spectroscopy and ethyl vinyl ether (EVE) trapping experiments were used to determine the reaction mechanism and QM formation, respectively. QMs were not generated during oxidative cleavage of the boronic esters but by subsequent transformation of the phenol products under physiological conditions. The oxidative deboronation is facilitated by electron‐withdrawing substituents, such as aromatic F, NO₂, or benzylic N⁺Me₃Br^?, whereas electron‐donating substituents or a better leaving group favor QM generation. Compounds containing an aromatic CH₃ or OMe group, or a good leaving group (Br), efficiently generate QMs under physiological conditions. Finally, a quantitative relationship between the structure and activity has been established for the arylboronic esters by using a Hammett plot. The reactivity of the arylboronic acids/esters and the inhibition or facilitation of QM formation can now be predictably adjusted. This adjustment is important as some applications may benefit and others may be limited by QM generation.     

Near‐Infrared‐Controlled,Targeted Hydrophobic Drug‐Delivery System for Synergistic Cancer Therapy

Hydrophobicity has been an obstacle that hinders the use of many anticancer drugs. A critical challenge for cancer therapy concerns the limited availability of effective biocompatible delivery systems for most hydrophobic therapeutic anticancer drugs. In this study, we have developed a targeted near‐infrared (NIR)‐regulated hydrophobic drug‐delivery platform based on gold nanorods incorporated within a mesoporous silica framework (AuMPs). Upon application of NIR light, the photothermal effect of the gold nanorods leads to a rapid rise in the local temperature, thus resulting in the release of the entrapped drug molecules. By integrating chemotherapy and photothermotherapy into one system, we have studied the therapeutic effects of camptothecin‐loaded AuMP‐polyethylene glycol‐folic acid nanocarrier. Results revealed a synergistic effect in vitro and in vivo, which would make it possible to enhance the therapeutic effect of hydrophobic drugs and decrease drug side effects. Studies have shown the feasibility of using this nanocarrier as a targeted and noninvasive remote‐controlled hydrophobic drug‐delivery system with high spatial/temperal resolution. Owing to these advantages, we envision that this NIR‐controlled, targeted drug‐delivery method would promote the development of high‐performance hydrophobic anticancer drug‐delivery system in future clinical applications.     

Carbon Dots Prepared by Hydrothermal Treatment of Dopamine as an Effective Fluorescent Sensing Platform for the Label‐Free Detection of Iron(III) Ions and Dopamine

A facile, economic and green one‐step hydrothermal synthesis route using dopamine as source towards photoluminescent carbon nanoparticles (CNPs) is proposed. The as‐prepared CNPs have an average size about 3.8 nm. The emission spectra of the CNPs are broad, ranging from approximately 380 (purple) to approximately 525 nm (green), depending on the excitation wavelengths. Due to the favorable optical properties, the CNPs can readily enter into A549 cells and has been used for multicolor biolabeling and bioimaging. Most importantly, the as‐prepared CNPs contain distinctive catechol groups on their surfaces. Due to the special response of catechol groups to Fe³⁺ ions, we further demonstrate that such wholly new CNPs can serve as a very effective fluorescent sensing platform for label‐free sensitive and selective detection of Fe³⁺ ions and dopamine with a detection limit as low as 0.32 μM and 68 nM , respectively. The new “mix‐and‐detect” strategy is simple, green, and exhibits high sensitivity and selectivity. The present method was also applied to the determination of Fe³⁺ ions in real water samples and dopamine in human urine and serum samples successfully.     

Using “Threading Followed by Shrinking” to Synthesize Highly Stable Dialkylammonium‐Ion‐Based Rotaxanes

Herein, we report a “threading followed by shrinking” approach for the synthesis of rotaxanes by using an “oxygen‐deficient” macrocycle that contained two arylmethyl sulfone units and the dumbbell‐shaped salt bis(3,5‐dimethylbenzyl)ammonium tetrakis(3,5‐trifluoromethylphenyl)borate as the host and guest components, respectively. The extrusion of SO₂ from both of the arylmethyl sulfone units of the macrocyclic component in the corresponding [2]pseudorotaxane resulted in a [2]rotaxane that was sufficiently stable to maintain its molecular integrity in CD₃SOCD₃ at 393 K for at least 5 h.     

Design and Synthesis of Lipidic Organoalkoxysilanes for the Self‐Assembly of Liposomal Nanohybrid Cerasomes with Controlled Drug Release Properties

This paper reports the facile design and synthesis of a series of lipidic organoalkoxysilanes with different numbers of triethoxysilane headgroups and hydrophobic alkyl chains linked by glycerol and pentaerythritol for the construction of cerasomes with regulated surface siloxane density and controlled release behavior. It was found that the number of triethoxysilane headgroups affected the properties of the cerasomes for encapsulation efficiency, drug loading capacity, and release behavior. For both water‐soluble doxorubicin (DOX) and water‐insoluble paclitaxel (PTX), the release rate from the cerasomes decreased as the number of triethoxysilane headgroups increased. The slower release rate from the cerasomes was attributed to the higher density of the siloxane network on the surface of the cerasomes, which blocks the drug release channels. In contrast to the release results with DOX, the introduction of one more hydrophobic alkyl chain into the cerasome‐forming lipid resulted in a slower release rate of PTX from the cerasomes due to the formation of a more compact cerasome bilayer. An MTT viability assay showed that all of these drug‐loaded cerasomes inhibited proliferation of the HepG2 cancer cell line. The fine tuning of the chemical structure of the cerasome‐forming lipids would foster a new strategy to precisely regulate the release rate of drugs from cerasomes.     

Durable antimicrobial cotton fabrics containing stable quaternarized N-halamine groups

A novel N-halamine precursor with tertiary amino group (5,5-dimethylhydantoinyl-3-ylethyl)-dimethylamine (DEADH), was synthesized and then covalently bonded onto cotton fabrics modified by 3-chloropropyltrimethoxysilane to form quaternarized N-halamine precursor grafted cotton fabrics which could be transferred to N-halamine structure upon exposure to dilute sodium hypochlorite solution. The grafted cotton fabrics were characterized by FT-IR, X-ray photoelectron spectroscopy, and field emission scanning electron microscope. The antimicrobial test showed that the cotton fabrics grafted with the quaternarized N-halamine were capable of 7-log inactivation of Staphylococcus aureus and Escherichia coli O157:H7 within 1 min of contact time. Very interestingly, it was found that the grafting process and following chlorination had almost no adverse effect on the tensile strength of cotton fabrics. Furthermore, the antimicrobial cotton fabrics exhibited good washing durability and stability.     

膦手性丙炔胺脯氨酸磷酸酯螺旋聚合物的合成与表征

通过添加对映体拆分剂,合成了4种含膦手性的丙炔胺磷酸酯单体[HC帒CC H2NH(PO)R1R2].单体1,R1=OPh,R2=NC4H7COOCH3;单体2,R1=OPh,R2=NC4H7COOCH2CH3;单体3,R1=OPh,R2=NC4H7-COOC(CH3)3;单体4,R1=Ph,R2=NC4H7COOC(CH3)3].1H-NMR和31P-NMR表征可知对映体(单体1)不能被拆分剂拆分,而单体2、单体3、单体4通过拆分剂可以制得单一手性的磷化合物.以(nbd)Rh+[η6-C6H5B--(C6H5)3]为催化剂,以三氯甲烷为溶剂成功得到聚合物分子量范围在0.4×10-4～0.7×10-4,分子量分布在1.26～1.98范围的3种含手性膦侧基的丙炔胺类聚合物.比旋光度([α]D)、圆二色谱(CD)对聚合物的不同侧基及温度对光学活性的影响表明,聚合物具有良好的光学活性且能够形成单一方向的螺旋构象,说明膦手性在构建螺旋聚合物具有重要作用.     

铈对三角帆蚌钙代谢影响的研究

研究了不同浓度稀土Ce3+(0,0.5,1.0,2.5 mg·L-1)处理30,60 d时对2龄植片三角帆蚌钙代谢和珍珠质沉积的影响。结果表明:Ce3+对三角帆蚌珍珠质沉积量、外套膜和鳃组织中组织钙含量、钙调蛋白基因mRNA的表达量、腺苷三磷酸酶(ATPase)活性、碱性磷酸酶(ALP)活性的影响总体上均表现出明显的"低促高抑"的剂量效应和高浓度下"先促后抑"的时间效应。推测稀土Ce3+对钙调蛋白基因mRNA表达水平及关键酶活性的调节可能是其影响三角帆蚌钙代谢和珍珠质沉积的途径之一。     

改进片铸与烧结技术制备高性能钕铁硼磁体的研究

通过优化合金成分设计与改进速凝片铸技术、烧结技术,应用国内通用的工业生产烧结钕铁硼磁体的各类原材料,在工业生产线上实现了45UH高性能烧结钕铁硼磁体的批量生产。SEM观察和XRD分析结果表明:磁体具有比较高的取向度;其显微组织致密、精细而均匀,平均晶粒尺寸约为5μm。45UH烧结钕铁硼磁体的典型磁性能为Br=1.363 T,Hcb=1060 kA.m-1,Hcj=2140 kA.m-1,Hk=1625 kA.m-1,(BH)max=366.0 kJ.m-3;其Hcj/79.6 kA.m-1+(BH)max/7.96 kJ.m-3=72.8。在295～453 K温度区间,其剩磁与内禀矫顽力的温度系数分别为-0.108%.K-1和-0.486%.K-1。当L/D=0.7时,在473 K保持2 h磁体开路磁通不可逆损失为4.1%左右。批量生产的45UH烧结钕铁硼磁体,其常温磁性能优异,温度稳定性良好。