In Situ Exfoliating and Generating Active Sites on Graphene Nanosheets Strongly Coupled with Carbon Fiber toward Self‐Standing Bifunctional Cathode for Rechargeable Zn–Air Batteries

The self‐standing electrode nanomaterials with highly effective bifunctional electrocatalysis for oxygen reduction and evolution reactions (ORR/OER) are important for practical applications in metal–air batteries. Herein, a defect‐enriched and pyridinic‐N (PN) dominated bifunctional electrocatalyst with novel core–shell architecture (DN‐CP@G) is successfully fabricated by in situ exfoliating graphene from carbon paper followed by high temperature ammonia treatment. Benefitting from its strongly coupled core–shell structure, abundant defective sites and high‐content PN dopants, the DN‐CP@G displays an excellent electrocatalytic (ORR and OER) activity and stability in alkaline media, which are comparable to commercial Pt/C and Ir/C catalysts. The experiment, and theoretical calculations demonstrate that the electrocatalytic activities of carbon materials strongly depend on their defective sites and PN dopants. By directly using DN‐CP@G as a self‐standing electrode, the assembled zinc–air battery demonstrates a high discharge performance and outstanding long‐term cycle stability with at least 250 cycles, which is much superior to the mixed Pt/C and Ir/C electrodes. Remarkably, the DN‐CP@G based all‐solid‐state battery also reveals a good discharge and cycle performance. A facile and cost‐efficient approach to prepare highly effective bifunctional self‐standing electrode is provided by in situ generation of active sites on carbon support for metal–air batteries.     

Changes in trait and phylogenetic diversity of leaves and absorptive roots from tropical to boreal forests

Plant and Soil - Low-molecular-weight organic anions (carboxylates) influence rhizosphere processes and may enhance plant phosphorus acquisition. We examined the root exudate profile of a range of...     

Chenia zanderi C.Feng & J.Kou (Pottiaceae,Musci), a new species from Yunnan,China

A new species, Chenia zanderi C.Feng & J.Kou, from Xishan Forest Park in Yunnan Province, China is described and illustrated. Particularly distinctive features of the new species are the fragile stems and leaves fragile along their insertions, narrow leaves usually constricted near the middle, broadly rounded leaf apices with a long apiculus, large distal laminal cells with numerous solid and bifurcate papillae, a narrow groove on the distal ventral surface of the costa, and absence of a costal stereid band. A key for the species recognised in Chenia R.H.Zander is also provided.     

Serum miR-518e-5p is a potential biomarker for secondary imatinib-resistant gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of the intestinal tract. Imatinib is used as first-line therapy for GIST patients; however, secondary imatinib resistance poses a significant clinical challenge. Here, we analyzed serum miRNA expression profiles to identify specific serum miRNAs that could be used as early diagnostic markers. Candidate miRNAs were validated using Taqman quantitative PCR with serum samples from secondary imatinib-resistant GIST patients (n?=?39), imatinib-sensitive GIST patients (n?=?37), and healthy controls (n?=?28). Serum miR-518e-5p and miR-548e levels were higher in secondary imatinib-resistant GIST than imatinib-sensitive GIST patients or healthy controls (P?<?0.0001). However, ROC analysis indicated that only miR-518e-5p could distinguish imatinib-resistant GIST. To discriminate imatinib-resistant from imatinib-sensitive GIST patients, the AUC for serum miR-518e-5p was 0.9938, with 99.8% sensitivity and 82.1% specificity. Serum miR-518e-5p could also discriminate imatinib-resistant GIST patients from healthy controls with 99.9% sensitivity and 97.4% specificity. These data indicate that serum miR-518e-5p is a potentially promising non-invasive biomarker for early detection and diagnosis of secondary imatinib-resistant GIST.     

Differential regulation of motor neuron survival and choline acetyltransferase expression following axotomy

Although it is well known that motor neuron survival following axotomy is enhanced with maturation, the ability of surviving neurons to express the cholinergic enzyme choline acetyltransferase (ChAT) following axotomy has not been closely examined. Moreover, the utility of the facial nucleus in studies of motoneuron response to injury and to trophic factors, coupled with the increasing importance of the mouse in gene targeting, compelled us to investigate the age dependence of neuronal survival and ChAT expression in the mouse facial nucleus following axotomy. We cut the facial nerve at postnatal day (P)4, 7, 14, 21, and 28 or in the adult and used Nissl staining and ChAT immunocytochemistry to quantitate survival and ChAT expression, respectively, following 1, 2, or 3 weeks' survival at each age. We confirm in this model that the rate and extent of motor neuron death following axotomy is reduced with increasing maturity. The surviving neurons maintain a high ChAT content through P21; however, axotomy from P28 through adulthood results in a striking reduction in ChAT immunoreactivity. That is, although axotomy at P21 results in 61% motor neuron survival, with virtually all of the surviving neurons being ChAT positive, axotomy in the adult results in 72% survival but only 9% of the neurons are ChAT positive. Thus, surviving motor neurons in the adult animals are only weakly cholinergic. These results indicate that a change in the regulation of ChAT expression occurs following P21 so that cell survival and enzyme levels are uncoupled. We suggest that the putative factor or factors that enhances motor neuron survival in maturity is not capable of maintaining ChAT expression. © 1995 John Wiley & Sons, Inc.     

Mechanisms of stimulation of vagal pulmonary C fibers by pulmonary air embolism in dogs

Chen, H. F., B. P. Lee, and Y. R. Kou. Mechanisms ofstimulation of vagal pulmonary C fibers by pulmonary air embolism indogs. J. Appl. Physiol. 82(3):765-771, 1997.We investigated the involvement of thecyclooxygenase metabolites and hydroxyl radical (^· OH) in thestimulation of vagal pulmonary C fibers (PCs) by pulmonary air embolism(PAE). Impulses were recorded from PCs in 51 anesthetized, open-chest,and artificially ventilated dogs. Fifty of 59 PCs were stimulated byinfusion of air into the right atrium (0.2 ml ^· kg^{1 ·} min¹for 10 min). As a group (n = 59), PCactivity increased from a baseline of 0.4 ± 0.1 to a peak of 1.7 ± 0.2 impulses/s during the period from 1 min before to 2 min afterthe termination of PAE induction. In PCs initially stimulated by PAEinduction, PAE was repeated after the intervening treatment (iv) withsaline (n = 9), ibuprofen (acyclooxygenase inhibitor; n = 11), ordimethylthiourea (a ^· OH scavenger;n = 12). The responses of PCs to PAEwere not altered by saline vehicle but were abolished by ibuprofen and significantly attenuated by dimethylthiourea. Although hyperinflation of the lungs reversed the PAE-induced bronchomotor responses, it didnot reverse the stimulation of PCs (n = 8). These results suggest that 1)cyclooxygenase products are necessary for the stimulation of PCs byPAE, whereas changes in lung mechanics are not, and2) the functional importance ofcyclooxygenase products may be mediated in part through the formationof ^· OH.

     

PRODUCTION OF MEMBRANE WHORLS IN RAT LIVER BY SOME INHIBITORS OF PROTEIN SYNTHESIS

Inhibitors of protein synthesis capable of differential effects on nascent peptide synthesis on membrane-bound and free polyribosomes were employed to investigate the structure and function of cellular membranes of liver. The formation of membranous whorls in the cytoplasm and distension of nuclear membranes were induced by inhibitors of protein synthesis (i.e., cycloheximide and emetine) which predominantly interfere with nascent peptide synthesis on membrane-bound polyribosomes in situ. Other inhibitors of protein synthesis such as puromycin and fusidic acid, which inhibit nascent peptide synthesis on both free and membrane-bound polyribosomes, and chloramphenicol, which inhibits mitochondrial protein synthesis, did not induce these alterations. Cycloheximide, puromycin, and chloramphenicol produce some common cellular lesions as reflected by similar alterations in morphology, such as swelling of mitochondria, degranulation of rough endoplasmic reticulum, and aggregation of free ribosomes. The process of whorl formation in the cytoplasm, the incorporation of [³H]leucine and of [³H]choline into endoplasmic reticulum and the total NADPH-cytochrome c reductase activity of the endoplasmic reticulum were determined. During maximum formation of membranous whorls, [³H]leucine incorporation into cytoplasmic membranes was inhibited, while [³H]choline incorporation into these structures was increased; maximum inhibition of protein synthesis and stimulation of choline incorporation into endoplasmic reticulum, however, preceded whorl formation. Cycloheximide decreased the activity of NADPH-cytochrome c reductase of rough endoplasmic reticulum, but increased NADPH-cytochrome c reductase activity of smooth endoplasmic reticulum. In addition, cycloheximide decreased the content of hemoprotein in both the microsomal and mitochondrial fractions of rat liver, and the activities of mixed function oxidase and of oxidative phosphorylation were impaired to different degrees. Succinate-stimulated microsomal oxidation was also inhibited. The possible mechanisms involved in the formation of membranous whorls, as well as their functions, are discussed.     

Some pungent principles of spices cause the adrenal medulla to secrete catecholamine in anesthetized rats

We recently reported that capsaicin, a pungent principle of hot red pepper, evokes catecholamine secretion from the rat adrenal medulla. In this study, the effects of some pungent principles of spices on adrenal catecholamine secretion were investigated as compared with that of capsaicin. An increase in catecholamine, especially epinephrine, secretion was observed not only on capsaicin infusion but also on piperine (a pungent principle of pepper) and zingerone (ginger) infusion. Even on infusion of the same amount (650 nmol/kg, i.v.), the order of potency as to catecholamine secretion was capsaicin much greater than piperine greater than or equal to zingerone. While, sulfur-containing and volatile pungent principles, allylisothiocyanate (mustard, etc.) and diallyldisulfide (garlic, etc.), did not even cause slight catecholamine secretion. Furthermore, these adrenergic secretagogues were readily transported via the gut into the body. These results indicate that some pungent principles of dietary spices can induce a warming action via adrenal catecholamine secretion.