Hierarchically Porous Carbon Cloth–Polyaniline (CC–PANI) Composite Supercapacitor Electrodes with Enhanced Stability

In this work, hierarchically porous composites were prepared in the form of activated carbon cloth (CC) Busofit T–1–055 filled with an electrically conductive polymer, polyaniline (PANI), for use as pseudocapacitive electrodes of electrochemical supercapacitors (SCs). CC fibers have high nanoporosity and specific surface area, so it was possible to deposit (via the chemical oxidative polymerization of aniline) a significant amount of PANI on them in the form of a thin layer mainly located on the inner surface of the pores. Such morphology of the composite made allowed the combining of the high capacitive characteristics of PANI with the reversibility of electrochemical processes, high columbic efficiency and cyclic stability rather typical for carbon materials of double-layer SCs. The highest capacitance of composite electrodes of about 4.54 F/cm2 with high cyclic stability (no more than 8% of capacity loss after 2000 charge–discharge cycles with a current density of 10 A/cm2) and columbic efficiency (up to 98%) was achieved in 3 M H2SO4 electrolyte solution when PANI was synthesized from an aniline hydrochloride solution with a concentration of 0.25 M. Trasatti analysis revealed that 27% of specific capacitance corresponded to pseudocapacitance, and 73% to the double-layer capacitance

Crystallochemical aspect of clay and clayish matter minerals luminescence

X-ray luminescence (XRL) spectra in optical range of wave-lengths and thermoluminescence (TL) curves of several clay and clayish matter minerals were recorded for the first time. Mineral composition of all the samples was determined on the base of X-ray diffraction results. It was stated that XRL of clay minerals is related to their crystallochemical characteristics (type and degree of regularity of structure and isomorphism occurrence in particular). In the opinion of the authors, differences between luminescent characteristics of halloysite and kaolin minerals are related to syngony (triclinic or monoclinic) and possibility of Si4 + substitution with Al3 + in tetrahedral coordination that lead to uncompensated charges appearing and formation of luminescence centres based on silicon and aluminium tetroxides

Crystallochemical aspect of clay and clayish matter minerals luminescence

X-ray luminescence (XRL) spectra in optical range of wave-lengths and thermoluminescence (TL) curves of several clay and clayish matter minerals were recorded for the first time. Mineral composition of all the samples was determined on the base of X-ray diffraction results. It was stated that XRL of clay minerals is related to their crystallochemical characteristics (type and degree of regularity of structure and isomorphism occurrence in particular). In the opinion of the authors, differences between luminescent characteristics of halloysite and kaolin minerals are related to syngony (triclinic or monoclinic) and possibility of Si4 + substitution with Al3 + in tetrahedral coordination that lead to uncompensated charges appearing and formation of luminescence centres based on silicon and aluminium tetroxides

Skeletal muscle expression of the adhesion-GPCR CD97: CD97 deletion induces an abnormal structure of the sarcoplasmatic reticulum but does not impair skeletal muscle function

CD97 is a widely expressed adhesion class G-protein-coupled receptor (aGPCR). Here, we investigated the presence of CD97 in normal and malignant human skeletal muscle as well as the ultrastructural and functional consequences of CD97 deficiency in mice. In normal human skeletal muscle, CD97 was expressed at the peripheral sarcolemma of all myofibers, as revealed by immunostaining of tissue sections and surface labeling of single myocytes using flow cytometry. In muscle cross-sections, an intracellular polygonal, honeycomb-like CD97-staining pattern, typical for molecules located in the T-tubule or sarcoplasmatic reticulum (SR), was additionally found. CD97 co-localized with SR Ca2+-ATPase (SERCA), a constituent of the longitudinal SR, but not with the receptors for dihydropyridine (DHPR) or ryanodine (RYR), located in the T-tubule and terminal SR, respectively. Intracellular expression of CD97 was higher in slow-twitch compared to most fast-twitch myofibers. In rhabdomyosarcomas, CD97 was strongly upregulated and in part more N-glycosylated compared to normal skeletal muscle. All tumors were strongly CD97-positive, independent of the underlying histological subtype, suggesting high sensitivity of CD97 for this tumor. Ultrastructural analysis of murine skeletal myofibers confirmed the location of CD97 in the SR. CD97 knock-out mice had a dilated SR, resulting in a partial increase in triad diameter yet not affecting the T-tubule, sarcomeric, and mitochondrial structure. Despite these obvious ultrastructural changes, intracellular Ca2+ release from single myofibers, force generation and fatigability of isolated soleus muscles, and wheel-running capacity of mice were not affected by the lack of CD97. We conclude that CD97 is located in the SR and at the peripheral sarcolemma of human and murine skeletal muscle, where its absence affects the structure of the SR without impairing skeletal muscle functio

CD97 co-localizes with SERCA.

<p><b>A</b> In cross-sections, CD97 NTF^GAIN CLB-CD97/3 and SERCA2 Abs showed a honeycomb-like staining pattern, indicating localization of CD97 within the SR or T-tubules (scale bar 10 µm). A blurred, fuzzy staining was seen with the CD97 NTF^GAIN Ab MEM-180 inside the fibers. <b>B</b> In longitudinal sections, a striated pattern was seen with CLB-CD97/3 and MEM-180, whereas staining for RYR and DHPR yielded two parallel dotted lines. <b>C</b> The CD97 Abs CLB-CD97/3 and NTF^Endo3 ab13345 co-localized with SERCA2 in longitudinal sections, whereas the MEM-180 projected to the M-band.</p

Calcium release from myofibers and muscle force generation and fatigability are normal in CD97Ko mice.

<p><b>A–D</b> Intracellular Ca²⁺ release from the SR into cytoplasm of single muscle flexor digitorum brevis (FDB) myofibers. Mean traces of the analyzed FDB fibers from adult WT and CD97Ko represent [Ca²⁺]i responses measured by Fura-2AM video microscopy. Variations in [Ca²⁺]i over time are represented by the ratio fluorescence intensities (FI) at 340 and 380 nm excitation wavelengths after dynamic background subtraction. Fibers were exposed to calcium release activators after 60 s. From 120 s till 300 s, medium without a substance was applied again. 5 mice per strain and from each mouse two to three fibers were analyzed (mean ± SEM, Mann-Whitney test). <b>A</b> Basal 340/380 fluorescence intensities (FI) ratios were unchanged in both WT and CD97ko fibers. <b>B, C</b> 100 mM KCl (B) and 30 mM caffeine (C) increased [Ca²⁺]i comparably in WT and CD97Ko fibers. <b>D</b> Application of 5 µM ionomycin as a positive control induced a fast total store [Ca²⁺]i release from the SR. <b>E, F</b> Functional analysis of skeletal muscles of CD97Ko and WT mice at the age of 2 and 4 months. Force-frequency relationship (E) and muscle fatigability, determined as percentage of decline in force over 15 s (F), were measured in soleus muscles (n = 8 mice/strain; mean ± SEM, t-test).</p

The SR in skeletal muscles of CD97Ko mice is morphologically abnormal.

<p><b>A</b> Representative electron micrographs of longitudinal ultrathin sections of WT and CD97Ko mice. Note the altered morphology of the SR which was frequently swollen (arrow heads), whereas myofibrils and mitochondria retained normal structures in CD97Ko mice. <b>B-E</b> Quantitative measurements of several morphometric parameters based on electron micrographs of the quadriceps muscle (n = 4 mice/strain, 25 micrographs/animal, mean ± SEM; *p<0.05, **p<0.01, *** p<0.001, t-test). D shows the number of AI-junctions and triads/100 µm² area occupied by myofibrils.</p

Unchanged wheel-running activity of CD97Ko mice.

<p>Measures of wheel-running activity of CD97Ko and WT mice (n = 16 mice/strain; mean ± SEM; t-test, *p<0.05). Running for 24 h was repeated every 2 weeks. <b>A–E</b> Average and maximum acceleration (A), duration/run and over 24 h (B), average and maximum speed (C), and distance/run or over 24 h (D) were measured. Body weight was monitored (E).</p

CD97 is present in murine skeletal muscle.

<p><b>A</b> Schematic presentation of the murine CD97 isoforms containing three (EGF124), four (EGF1234), or four EGF-like domains plus 45 additional amino acids (EGF12×34) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100513#pone.0100513-Hamann4" target="_blank">[47]</a>. Indicated are the binding sites of the Abs used in this study. The CD97 NTF Ab AF3734 is not shown because its exact binding site within the NTF is unknown. <b>B</b> Nuclear β-galactosidase staining (blue) with fast red counterstaining in the soleus muscle of a CD97-lacZ knock-in mouse; scale bar 50 µm. <b>C, D</b> CD97 mRNA levels of murine tissues (C) and cell lines (D) were quantified by RT-PCR. RSP29 normalized log₂ x-fold mRNA levels compared to brain and CMT-93 cells, which were set to one, are given (n = 3, mean ± SEM). <b>E</b> The upper part of the Western blot was incubated with the CD97 NTF Ab AF3734, whereas the lower part was incubated with a CD97 CFT^ICD Ab. 1: WT mouse, soleus muscle, 2: CD97Ko mouse, soleus muscle, 3: WT mouse, enriched sarcolemma, 4: C2C12 myocytes cultured in 10% FCS, 5: C2C12 myoblasts cultured in 2% horse serum, 6: positive control duodenum Tg(villin-CD97) mouse overexpressing CD97(EGF1234) in intestinal epithelial cells <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100513#pone.0100513-Becker1" target="_blank">[16]</a>. In lanes 1–2, 20 µg, in lanes 3–5, 10 µg, and in lane 6, 5 µg protein were separated; Mr: molecular weight standard. Loading was controlled with an α-tubulin Ab, shown in the lower panel. Using the CFT^ICD Ab, a 26-kDa band representing the CD97 CTF was present in all samples except the CD97Ko mouse (lane 2). The CD97 NTF AF3734 Ab detected the NTF of the CD97(EGF1234) isoform expressed in the Tg(villin-CD97) mouse (arrow head). Additional NTF bands were present in the WT soleus muscle, the enriched sarcolemma, and the C2C12 lysates, perhaps representing the various CD97 isoforms and/or not N-glycosylated protein of these isoforms (arrows). <b>F</b> C2C12 myoblasts (undiff) showed higher levels of cell-surface CD97 compared to differentiated (diff) C2C12 myocytes in flow cytometry (mean fluorescence intensity, MFI; n = 5, mean ± SEM; ***p< 0.001, Mann-Whitney test). The right panel shows a representative flow cytometry plot.</p

CD97 staining pattern in normal human skeletal muscle.

<p>The CD97 NTF^EGF1 Ab BL-Ac(F2) stained malignant but not normal skeletal muscle and thus is not provided here.</p