Single-walled carbon nanotube gutter layer supported ultrathin zwitterionic microporous polymer membrane for high-performance lithium-sulfur battery.

Development of efficient lithium-sulfur (Li-S) battery requires the need to develop an appropriate functional separator that allows strong facilitation and transport of lithium ions together with limited passage of polysulfides. In this work, a multifunctional separator (TB-BAA/SWCNT/PP) is developed through spin coating of a novel zwitterionic microporous polymer (TB-BAA) on the gutter layer constructed from single-walled carbon nanotubes (SWCNT), where commercially available polypropylene (PP) separator is used to act as the mechanical support. SWCNT in this study serves as the first modification layer to decrease the size of the macropores in the PP separator, while the ultrathin TB-BAA top barrier layer with the presence of zwitterionic side chains allows the creation of confined ionic channels with both lithiophilic and sulfophilic groups. Due to the presence of available chemical interactions with lithium polysulfides, selective ion transport can be foreseen through such separator. In this regard, shuttle effect that is frequently encountered in Li-S battery can be suppressed effectively via implementing the as-obtained functional separator, resulting in the creation of credible and stable sulfur electrochemistry. The TB-BAA/SWCNT/PP-based Li-S battery has been investigated to possess high cycling ability (capacity fading per cycle of 0.055% over 500 cycles at 1 C) together with decent rate capability (736.6 mAh g-1 at 3 C). In addition, a high areal capacity retention of 5.03 mAh cm-2 after 50 cycles can be also obtained under raised sulfur loading (5.4 mg cm-2).

Zwitterionic covalent organic framework as a multifunctional sulfur host toward durable lithium-sulfur batteries.

The shuttle effect and slow redox kinetics of sulfur cathode are the most significant technical challenges to the practical application of lithium-sulfur (Li-S) battery. Herein, a novel zwitterionic covalent organic framework (ZW-COF) wrapped onto carbon nanotubes (CNTs), labeled as ZW-COF@CNT, is developed by a reversible condensation reaction of 1,3,5-benzenetricarboxaldehyde (BTA) and 3,8-diamino-6-phenylphenanthridine (DPPD) with CNTs as a template and a subsequently-one-step post-synthetic grafting reaction with 1,3-propanesultone. The experimental results showed that, after loading active material sulfur, zwitterionic ZW-COF@CNT can effectively suppress the shuttle effect of the soluble lithium polysulfides (LiPSs) in Li-S batteries, and exhibits better cycling behavior than the as-developed neutral COF@CNT. Specifically, the as-obtained ZW-COF@CNT based sulfur cathode can maintain a discharge capacity of 944 mAh/g after 100 cycles, while that of COF@CNT based sulfur cathode drops to (665 mAh/g) after 100 cycles. Moreover, the ZW-COF@CNT based sulfur cathode delivers an attractive prolonged cycling behavior with a low capacity decay rate of 0.046 % per cycle at 1 C. This work sheds new light on rational selection and design of functionalized COFs based sulfur cathode in the Li-S battery.

Overexpression of the 18 kDa translocator protein (TSPO) in the hippocampal dentate gyrus produced anxiolytic and antidepressant-like behavioural effects.

The 18 kDa translocator protein (TSPO) is a five transmembrane domain protein that plays a crucial role in neurosteroid (e.g., allopregnanolone) synthesis by promoting the transport of cholesterol to the inner mitochondrial membrane. This protein is predominantly expressed in steroid-synthesizing tissues, including the central and peripheral nervous system, affecting stress-related disorders such as anxiety and depression. Recent studies have focused on the hippocampal dentate gyrus, which is very important for involvement of anxiety and depression. However, the exact role that TSPO plays in the pathophysiology of anxiety and depression and the involvement of the hippocampal dentate gyrus in regulating these behavioural effects remain elusive. This study used the lentiviral vectors mediating TPSO overexpression to assess the effects of TPSO overexpression in the hippocampal dentate gyrus on anxiolytic and antidepressant-like behavioural effects in mice. The expression of TSPO and the concentration of allopregnanolone in hippocampus tissues (3 mm in diameter around the injection site on both sides) were measured by Western blot and ELISA, respectively. The results indicated that microinjection of the LV-TSPO resulted in a significant increase in TSPO expression and allopregnanolone concentration in the hippocampus. Moreover, TSPO overexpression of the mouse hippocampal dentate gyrus generated significant anxiolytic and antidepressant-like behavioural effects in a series of behavioural models. These effects were completely blocked by the TSPO antagonist PK11195 (3 mg/kg, intraperitoneally) and the 5α-reductase inhibitor finasteride (5 mg/kg,intraperitoneally). Meanwhile, the increased allopregnanolone was also reversed by PK11195 and finasteride. In addition, neither PK11195 nor finasteride had an effect on the expression of TSPO. Overall, our results are the first to suggest that the overexpression of TSPO in the hippocampal dentate gyrus produced anxiolytic and antidepressant-like behavioural effects that are partially mediated by downstream allopregnanolone biosynthesis. Our results suggest that TSPO would be a potential anxiolytic and antidepressant therapeutic target.

Grafting density dominant glass transition of dry polystyrene brushes.

The effects of the grafting densities (σp), molecular weights (Mn) and thicknesses of dry polystyrene (PS) brushes on their glass transition temperature (T) were investigated by ellipsometry. The results show that T strongly depends on the grafting density of the PS brushes. The T of the PS brushes with σp > 0.30 increases with decreasing Mn (or brush thickness) and is mainly dominated by entropic effects, in which the grafted chains are highly extended along the film thickness direction resulting in a sharp reduction in configurational entropy. The T of PS brushes with σp < 0.30 decreases with decreasing Mn (or brush thickness) which is mainly dominated by surface effects. For intermediate-density brushes (σp = 0.30), T becomes independent of Mn or brush thickness. The reason for this grafting density dependence of T is attributed to the transition of the PS brush conformation from mushroom-to-brush.

The architecture of the adsorbed layer at the substrate interface determines the glass transition of supported ultrathin polystyrene films.

To elucidate the mechanism underlying the effect of polymer/solid interfacial interactions on the dynamics of thin polymer films, the glass transition of thin end-functionalized polystyrene films supported on SiO2-Si, such as proton-terminated PS (PS-H), α,ω-dicarboxy-terminated PS (PS-COOH), and α,ω-dihydroxyl-terminated PS (PS-OH), was investigated. All the PS films exhibited a substantial depression in Tg with decreasing film thickness, while the extent of such depression was strongly dependent on the chemical structure of the end groups and molecular weights. It was found that T - T of the various PS films increased linearly with increasing hads/Rg, in which hads is the thickness of the interfacial adsorbed layer and Rg is the radius of gyration of PS. The hads/Rg is a direct reflection of the macromolecular chain conformation within the adsorbed layer which was affected by its end groups and molecular weights. These findings are in line with the work of Napolitano, and present direct experimental evidence.

Stepwise crystallization and the layered distribution in crystallization kinetics of ultra-thin poly(ethylene terephthalate) film.

Crystallization is an important property of polymeric materials. In conventional viewpoint, the transformation of disordered chains into crystals is usually a spatially homogeneous process (i.e., it occurs simultaneously throughout the sample), that is, the crystallization rate at each local position within the sample is almost the same. Here, we show that crystallization of ultra-thin poly(ethylene terephthalate) (PET) films can occur in the heterogeneous way, exhibiting a stepwise crystallization process. We found that the layered distribution of glass transition dynamics of thin film modifies the corresponding crystallization behavior, giving rise to the layered distribution of the crystallization kinetics of PET films, with an 11-nm-thick surface layer having faster crystallization rate and the underlying layer showing bulk-like behavior. The layered distribution in crystallization kinetics results in a particular stepwise crystallization behavior during heating the sample, with the two cold-crystallization temperatures separated by up to 20 K. Meanwhile, interfacial interaction is crucial for the occurrence of the heterogeneous crystallization, as the thin film crystallizes simultaneously if the interfacial interaction is relatively strong. We anticipate that this mechanism of stepwise crystallization of thin polymeric films will allow new insight into the chain organization in confined environments and permit independent manipulation of localized properties of nanomaterials.

Antidepressant-like effects of albiflorin extracted from Radix paeoniae Alba.

ETHNOPHARMACOLOGY RELEVANCE: Albiflorin, a monoterpene glycoside, is a main component of Radix paeoniae Alba, which could be a Chinese herbal medicine used in the treatment of psychiatric disorders. However, the exact role of albiflorin in depression is poorly understood. AIM OF THE STUDY: The current study aimed to evaluate the antidepressant effect of albiflorin in mice and rats, and the possible mechanism was also determined. MATERIALS AND METHODS: The antidepressant-like effects of albiflorin was determined by using animal models of depression including forced swim and tail suspension tests in mice and chronic unpredictable stress (CUS) in rats. The acting mechanism was explored by determining the effect of albiflorin on the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus by western blot and the levels of monoamine in the hippocampus by HPLC. RESULTS: Our results showed that 7 days treatment with albiflorin significantly decreased immobility time in the forced swimming test (FST) and the tail suspension test (TST) at doses of 3.5, 7.0 and 14.0mg/kg without alter the locomotor activity in mice. Moreover, western blot analysis showed that albiflorin could increase the expression of BDNF in the hippocampus. We further exposed rats to a chronic unpredictable stress (CUS) protocol for a period of 35d to induce depressive-like behaviors. We found that chronic treatment with albiflorin, at doses of 7.0 and 14.0mg (i.g., once daily for 35d), restored the sucrose preference in CUS rats. In the open-field test, albiflorin significantly increased the number of crossings and rearings in the CUS rats at three doses. Moreover, chronic treatment with albiflorin up-regulated the hippocampal BDNF expression levels and the hippocampal 5-HT, 5-HIAA, and NA levels. CONCLUSION: Albiflorin produced significant antidepressant-like effects, which were closely related to the hippocampal 5-HT/NE increase and BDNF expression. Our data indicated that albiflorin could be a potential anti-depressant drug.

[Recovery of infraorbital nerve iujury after middle facial fracture].

PURPOSE: To evaluate the recovery of infraorbital nerve injury after middle facial fracture. METHODS: 28 patients with infraorbital nerve injury were examined in l month, 3 months, 6 months and 12 months after operation by using sharp-blunt test, two-point discrimination,electric pain response test. The data were analyzed with SPSS12.0 software package for Student's t test. RESULTS: 25 cases (25 of 28) with injured nerve recovered normally.The average time of recovery was 25 weeks. The injured nerve didnot recover in 3 of 28. No chronic neuropathic pain was found. CONCLUSIONS: Most nerve dysfunctions following middle facial fracture are reversible and temporary,very few are permanent. If the injured nerve doesn't recover within 6 months, infraorbital nerve decompression may be selected to promote the recovery of the nerve function.