Ecofriendly Chemical Activation of Overlithiated Layered Oxides by DNA‐Wrapped Carbon Nanotubes

Despite their exceptionally high capacity, overlithiated layered oxides (OLO) have not yet been practically used in lithium‐ion battery cathodes due to necessary toxic/complex chemical activation processes and unsatisfactory electrochemical reliability. Here, a new class of ecofriendly chemical activation strategy based on amphiphilic deoxyribose nucleic acid (DNA)‐wrapped multiwalled carbon nanotubes (MWCNT) is demonstrated. Hydrophobic aromatic bases of DNA have a good affinity for MWCNT via noncovalent π–π stacking interactions, resulting in core (MWCNT)‐shell (DNA) hybrids (i.e., DNA@MWCNT) featuring the predominant presence of hydrophilic phosphate groups (coupled with Na⁺) in their outmost layers. Such spatially rearranged Na⁺–phosphate complexes of the DNA@MWCNT efficiently extract Li⁺ from monoclinic Li₂MnO₃ of the OLO through cation exchange reaction of Na⁺–Li⁺, thereby forming Li₄Mn₅O₁₂‐type spinel nanolayers on the OLO surface. The newly formed spinel nanolayers play a crucial role in improving the structural stability of the OLO and suppressing interfacial side reactions with liquid electrolytes, eventually providing significant improvements in the charge/discharge kinetics, cyclability, and thermal stability. This beneficial effect of the DNA@MWCNT‐mediated chemical activation is comprehensively elucidated by an in‐depth structural/electrochemical characterization.     

Characteristics of soil water distribution and evaluation of recharge rate under different grazing history in the Xilin Gol Steppe北大核心CSCD

Aims In the Xilin Gol Steppe, human-induced grassland degradation and land desertification are becoming increasingly severe. Critical evaluation of its impact on soil water and recharge rate is important for sustainable management of soil health and water resources in the region. Methods In order to determine the effect of different grazing history on dynamics of deep soil moisture contents and precipitation infiltration in the Xilin Gol Steppe, three sites with different grazing history (ungrazed since 1979 or UG79, ungrazed since 1999 or UG99, and continuously grazed or CG) were selected with two sampling spots for each site. The precipitation infiltration was estimated using the chloride mass balance method. Important findings The results showed that: 1) Average soil water content of 0–5 m was 7.1%, 6.9%, and 6.3% for UG79, UG99, and CG, respectively, with no significant difference. In the soil layer of 0–2 m, the soil water content of UG79 was 26.6% and 33.7% higher than that of UG99 and CG, respectively. The soil water content of UG79 was significantly higher than that of UG79 and UG99 (p < 0.05) with no significant difference between UG99 and CG. The soil water storage capacity of UG79 was 87.19 mm higher than UG99 and 82.52 mm higher than CG. In the deep layer of 2–5 m, no significant difference in the soil water content and the water storage among different grazing history. 2) The factors influencing soil water differed among different grazing treatments. The soil water content was mainly affected by the vegetation conditions and soil properties for the 0–2 m soil layer, but by the composition of soil particles for the 2–5 m soil layer. The effect of soil organic matter (SOM) content on soil water increased with time without grazing. Soil water content of the entire soil profile of UG79 was significantly correlated with soil texture and SOM content (p < 0.01). Soil water content of 0–2 m was significantly correlated with SOM content (p < 0.01), soil water content of 2–5 m was significantly correlated with the soil texture (p <0.01), but soil moisture content of UG99 and CG had no significant correlation with SOM content. 3) Annual recharge rate was 5.64, 3.54, and 2.45 mm·a –1 for UG79, UG99 and CG, respectively. The recharge rate increased by 44.5% and 130.2% for the site without grazing for 15 and 35 years, respectively. The recharge rate in the study area ranged from 1.95 to 7.61 mm·a –1 , accounting for only 0.55%–2.13% of the precipitation. In summary, ungrazing treatment can increase soil water retention, total water storage capacity, and recharge. © 2018 Editorial Office of Chinese Journal of Plant Ecology. All Rights Reserved.     

Loss of autophagy diminishes pancreatic beta cell mass and function with resultant hyperglycemia

Autophagy is a cellular degradation-recycling system for aggregated proteins and damaged organelles. Although dysregulated autophagy is implicated in various diseases including neurodegeneration, its role in pancreatic beta cells and glucose homeostasis has not been described. We produced mice with beta cell-specific deletion of Atg7 (autophagy-related 7). Atg7 mutant mice showed impaired glucose tolerance and decreased serum insulin level. beta cell mass and pancreatic insulin content were reduced because of increased apoptosis and decreased proliferation of beta cells. Physiological studies showed reduced basal and glucose-stimulated insulin secretion and impaired glucose-induced cytosolic Ca2+ transients in autophagy-deficient beta cells. Morphologic analysis revealed accumulation of ubiquitinated protein aggregates colocalized with p62, which was accompanied by mitochondrial swelling, endoplasmic reticulum distension, and vacuolar changes in beta cells. These results suggest that autophagy is necessary to maintain structure, mass and function of pancreatic beta cells, and its impairment causes insulin deficiency and hyperglycemia because of abnormal turnover and function of cellular organelles.     

Bis deficiency results in early lethality with metabolic deterioration and involution of spleen and thymus

Bcl-2 interacting cell death suppressor (Bis), also known as Bag3 or CAIR-1, is involved in antistress and antiapoptotic pathways. In addition to Bcl-2, Bis binds to several proteins, suggesting it has diverse functions in normal and pathological conditions. To better define the physiological function of Bis in vivo, we developed bis-deficient mice with a cre-loxP system. Targeted disruption of exon 4 of the bis gene was demonstrated by Southern blotting and PCR, and Western blotting showed that no intact or truncated Bis protein was synthesized in bis(-/-) mice. While heterozygotes were fertile and appeared normal, Bis-deficient mice showed growth retardation and died by 3 wk after birth. The relative weight of the thymus and spleen was reduced and the total numbers of white blood cells, splenocytes, and thymocytes were significantly reduced compared with wild-type littermates. Serum profiles indicated significant hypoglycemia as well as decrease in triglyceride and cholesterol levels. Expression profiles of metabolic genes indicated that gluconeogenesis and beta-oxidation are activated in the liver of bis(-/-) mice. This activation, as well as a decrease in peripheral fat and an induction of fatty liver, appears to be an adaptive response to hypoglycemia. Our study reveals that the absence of Bis has considerable influences on postnatal growth and survival, possibly due to a nutritional impairment.     

The diversity of beetle assemblages in different habitat types in Sabah, Malaysia

The diversity of beetle assemblages in different habitat types (primary forest, logged forest, acacia plantation and oil palm plantation) in Sabah, Malaysia was investigated using three different methods based on habitat levels (Winkler sampling, flight-interception-trapping and mist-blowing). The overall diversity was extremely high, with 1711 species recorded from only 8028 individuals and 81 families (115 family and subfamily groups). Different degrees of environmental changes had varying effects on the beetle species richness and abundance, with oil palm plantation assemblage being most severely affected, followed by acacia plantation and then logged forest. A few species became numerically dominant in the oil palm plantation. In terms of beetle species composition, the acacia fauna showed much similarity with the logged forest fauna, and the oil palm fauna was very different from the rest. The effects of environmental variables (number of plant species, sapling and tree densities, amount of leaf litter, ground cover, canopy cover, soil pH and compaction) on the beetle assemblage were also investigated. Leaf litter correlated with species richness, abundance and composition of subterranean beetles. Plant species richness, tree and sapling densities correlated with species richness, abundance and composition of understorey beetles while ground cover correlated only with the species richness and abundance of these beetles. Canopy cover correlated only with arboreal beetles. In trophic structure, predators represented more than 40% of the species and individuals. Environmental changes affected the trophic structure with proportionally more herbivores (abundance) but fewer predators (species richness and abundance) in the oil palm plantation. Biodiversity, conservation and practical aspects of pest management were also highlighted in this study.     

N‐cadherin/catenin–based costameres in cultured chicken cardiomyocytes

N‐cadherin is a member of the Ca²⁺‐dependent cell adhesion molecules and plays an important role in the assembly of the adherens junction in chicken cardiomyocytes. In addition to being present at the cell‐cell junction, N‐cadherin is associated with costameres in extrajunctional regions. The significance of the N‐cadherin‐associated costameres and whether catenins are components of costameres in chicken cardiomyocytes are not known. In this study, double‐labeling immunofluorescence microscopy was used to determine the extrajunctional distribution of both N‐cadherin and its cytoplasmic associated proteins, α‐ and β‐catenins, and their relationship to myofibrillar Z‐disc α‐actinin. N‐cadherin, α‐, and β‐catenins were all found to be present at the extrajunctional region and, in some cases, were codistributed with myofibrillar α‐actinin exhibiting a periodic staining pattern. Confocal microscopy confirmed that both N‐cadherin and β‐catenin colocalized with peripheral myofibrillar α‐actinin on the dorsal surface of cardiomyocytes as components of the costameres. Intracellular application of antibodies specific for the cytoplasmic portions of N‐cadherin, α‐, and β‐catenin, either by electroporation or microinjection, resulted in myofibril disorganization and disassembly. These results suggest the existence of N‐cadherin/catenin‐based costameres in the dorsal surface of cultured chicken cardiomyocytes in addition to the integrin/vinculin‐based costameres found in the ventral surface and indicate that the former set of costameres is essential for cardiac myofibrillogenesis. J. Cell. Biochem. 75:93–104, 1999. © 1999 Wiley‐Liss, Inc.     

The lyotropic liquid crystal properties of n-octyl 1-O-beta-D-glucopyranoside and related n-alkyl pyranosides

X-ray diffraction patterns have been obtained for the lyotropic phases of n-octyl 1-O-beta-D-glucopyranoside and the related n-heptyl, n-nonyl and n-decyl compounds with water. The octyl compound exhibits all three liquid crystal phases and forms a micellar solution with increasing solvation, when the crystal come into contact with water at room temperature. The X-ray diffraction patterns show a one-dimensional lamellar phase with [dx] = 28.4 A, a three-dimensional face-centered cubic phase with [a] = 51.2 A, and a two-dimensional hexagonal phase with [a] = [b] = 36.7 A. The micellar solution has a distribution pattern with a maximum at [dx] = 33.8 A. Crystals of the heptyl, nonyl and decyl derivatives form only the lamellar phases and the micellar solution on contact with water at room temperature.