Solid‐state lithium polymer secondary batteries (LPB) are fabricated with a two‐electrode‐type cell construction of Li|solid‐state polymer electrolyte (SPE)|LiFePO4. Plasticizers of poly(ethylene glycol) (PEG)‐borate ester (B‐PEG) or PEG‐aluminate ester (Al‐PEG) are added into lithium‐conducting SPEs in order to enhance their ionic conductivity, and lithium bis‐trifluoromethansulfonimide (LiTFSI) is used as the lithium salt. An improvement of the electrochemical properties is observed upon addition of the plasticizers at an operation temperature of 60 °C. However, a decrease of discharge capacities abruptly follows after tens of stable cycles. To understand the origin of the capacity fading, electrochemical impedance techniques, ex‐situ NMR and scanning electron microscopy (SEM)/energy dispersive X‐ray spectroscopy (EDS) techniques are adopted. Alternating current (AC) impedance measurements indicate that the decrease of capacity retention in the LPB is related to a severe increase of the interfacial resistance between the SPE and cathode. In addition, the bulk resistance of the SPE film is observed to accompany the capacity decay. Ex situ NMR studies combined with AC impedance measurements reveal a decrease of Li salt concentration in the SPE film after cycling. Ex situ SEM/EDS observations show an increase of concentration of anions on the electrode surface after cycling. Accordingly, the anions may decompose on the cathode surface, which leads to a reduction of the cycle life of the LPB. The present study suggests that a choice of Li salt and an increase of transference number is crucial for the realization of lithium polymer batteries.
Two morphological types of appendages, an anchor-like appendage and a peritrichate fibril-type appendage, have been observed on cells of an adhesive bacterium, Acinetobacter sp. strain Tol 5, by use of recently developed electron microscopic techniques. The anchor extends straight to the substratum without branching and tethers the cell body at its end at distances of several hundred nanometers, whereas the peritrichate fibril attaches to the substratum in multiple places, fixing the cell at much shorter distances.Microbial adhesion is detrimental to both human life and industrial processes, causing infection and contamination by pathogens, dental decay, and biofilm formation, but it can also be beneficial in some environmental bioprocesses and in agriculture (5). Therefore, microbial adhesion has attracted much attention from researchers in various fields (2,5,8,20). Exopolymeric substances (EPS) (10,11,14,17) and proteinaceous appendages such as pili (4, 21) and flagella (3, 9) have been shown to be responsible for tenacious bacterial adhesion by forming a bridge between a cell and a surface. We previously isolated a rod-shaped, gram-negative, toluene-degrading bacterium, strain Tol 5, which was classified as Acinetobacter sp. (genomospecies 10) by 16S rRNA sequence analysis and physiological tests using the Micro Station system (BIOLOG) (13). This strain has a highly hydrophobic cell surface and is highly adhesive to solid surfaces. We have found that this adhesive property is beneficial to a biofiltration process for treating off gas containing volatile organic chemicals such as toluene because it allows the effective immobilization and accumulation of these bacterial cells with their high degradation activity on carrier materials. In the current study, we describe the cell appendages that mediate the adhesion of this bacterium to a solid surface.Bacterial cell appendages and EPS have been visualized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Compared with SEM, TEM provides high-resolution images by operating at higher electron-accelerating voltages (usually 70 to 100 kV for biotic samples). Of the several TEM techniques that have been used to observe living specimens (7,11,16,17), negative staining methods produce images that reflect the intact morphology of cell surface structures; such structures are unaffected by sample preparation because, in this method, the sample is mounted on a grid and subjected to electron staining without any other pretreatment. Indeed, many researchers have used TEM coupled with negative staining to visualize bacterial cell surface appendages involved in cell adhesion (9,12,15,21).To observe the cell surface structure of Tol 5 by TEM, the cells were grown until stationary phase at 28°C in 20 ml of a basal salt medium (Na 2 HPO 4 , 4.9 g; KH 2 PO 4 , 2.0 g; (NH 4 .2]) supplemented with 10 l of toluene in a 100-ml Erlenmeyer flask (13). To the flask were added four pieces (1.15 by 1.15 by 1.00 cm) of sponge carrier made of polyurethane, wit...
The self-assembly of ABA triblock copolymers comprising flexible amorphous poly(ethyl methacrylate) (PEMA, A block) and semiflexible liquid crystal (LC) polyester (B block) was investigated for amorphous block volume fractions (φ) ranging from 20% to 80%. Two copolymer series with different LC block molecular weights (M n,LC) were examined. At φ < 55%, block copolymers with M n,LC = 11 600 formed lamellar microdomains in which LC segments mostly extended along the lamella normal but folded to fit in the lamellae. When φ was augmented, the LC segment fold (N fold) increased to enhance the interface between the LC and amorphous segments and counterbalanced the increase in amorphous lamella thickness by reducing the LC lamella thickness. When φ > 68%, the LC lamellae were divided into cubes, transforming into spheres in the PEMA matrix. When M n,LC decreased to 6300, the copolymers showed similar morphology. However, the lamellae adopted zigzag configurations showing a greater tilting angle between the lamella normal to the LC chain axis with increasing φ. Thus, the LC and PEMA segments enhanced their interface by mutually sliding along the chain axis instead of increasing N fold.
Molecular mechanisms underlying the development and morphogenesis of oral epithelia, comprising the gustatory and nongustatory epithelium, remain unclear. Here, we show that Bcl11b, a zinc finger transcription factor, plays an important role in the development of lingual papillae, especially filiform papillae. In both gustatory and nongustatory epithelium, Bcl11b was expressed in keratin 14-positive epithelial basal cells, which differentiate into keratinocytes and/or taste cells. Loss of Bcl11b function resulted in abnormal morphology of the gustatory papillae: flattened fungiform papillae, shorter trench wall in the foliate and circumvallate papillae, and ectopic invagination in more than half of circumvallate papillae. However, Bcl11b loss caused no effect on differentiation of taste receptor cells. In nongustatory epithelium, the impact of Bcl11b deficiency was much more striking, resulting in a smooth surface on the tongue tip and hypoplastic filiform papillae in the dorsal lingual epithelium. Immunohistochemical analyses revealed that a keratinocyte differentiation marker, Tchh expression was severely decreased in the Bcl11b(-/-) filiform papillae. In addition, expression of Pax9, required for morphogenesis of filiform papillae and its downstream target genes, hard keratins, almost disappeared in the tongue tip and was decreased in the dorsal tongue of Bcl11b(-/-) mice. Gene expression analyses demonstrated a delayed onset of expression of epithelial differentiation complex genes, which disturbed barrier formation in the mutant tongue. These results indicate that Bcl11b regulates the differentiation of keratinocytes in the tongue and identify Bcl11b as an essential factor for the lingual papilla morphogenesis.
The smectic X 1 phase formed from the banana 4-bromo-1,3-phenylenebis[4-(4-n-tetradecanoxyphenyliminomethyl)benzoate] (4Br-P-14-O-PIMB) molecule, possesses a distinct two-dimensional structure with a long-range density modulation of $17:5 nm along the layer. The X 1 phase is formed upon cooling from the well-known B 2 phase, and then its characteristic modulated structure is retained at room temperature. A transmission electron microscopic (TEM) observation was performed for shadowed replica film which imprints the surface structure of the homeotropically aligned X 1 phase. The modulation was detected as clear stripes with periodicities ranging from 15 to 18 nm, which agree with the modulation length determined by X-ray measurement. The results confirm that the periodicity along the layer is not due to the simple density modulation occurring within a smooth layer, but can be explained by the layer undulation that creates the crests and troughs.
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