Mitochondrial oxidative damage reprograms lipid metabolism of renal tubular epithelial cells in the diabetic kidney.

The functional and structural changes in the proximal tubule play an important role in the occurrence and development of diabetic kidney disease (DKD). Diabetes-induced metabolic changes, including lipid metabolism reprogramming, are reported to lead to changes in the state of tubular epithelial cells (TECs), and among all the disturbances in metabolism, mitochondria serve as central regulators. Mitochondrial dysfunction, accompanied by increased production of mitochondrial reactive oxygen species (mtROS), is considered one of the primary factors causing diabetic tubular injury. Most studies have discussed how altered metabolic flux drives mitochondrial oxidative stress during DKD. In the present study, we focused on targeting mitochondrial damage as an upstream factor in metabolic abnormalities under diabetic conditions in TECs. Using SS31, a tetrapeptide that protects the mitochondrial cristae structure, we demonstrated that mitochondrial oxidative damage contributes to TEC injury and lipid peroxidation caused by lipid accumulation. Mitochondria protected using SS31 significantly reversed the decreased expression of key enzymes and regulators of fatty acid oxidation (FAO), but had no obvious effect on major glucose metabolic rate-limiting enzymes. Mitochondrial oxidative stress facilitated renal Sphingosine-1-phosphate (S1P) deposition and SS31 limited the elevated Acer1, S1pr1 and SPHK1 activity, and the decreased Spns2 expression. These data suggest a role of mitochondrial oxidative damage in unbalanced lipid metabolism, including lipid droplet (LD) formulation, lipid peroxidation, and impaired FAO and sphingolipid homeostasis in DKD. An in vitro study demonstrated that high glucose drove elevated expression of cytosolic phospholipase A2 (cPLA2), which, in turn, was responsible for the altered lipid metabolism, including LD generation and S1P accumulation, in HK-2 cells. A mitochondria-targeted antioxidant inhibited the activation of cPLA2f isoforms. Taken together, these findings identify mechanistic links between mitochondrial oxidative metabolism and reprogrammed lipid metabolism in diabetic TECs, and provide further evidence for the nephroprotective effects of SS31 via influencing metabolic pathways.

Porous Co3O4/NiO@C Chains Assembled from Nanosheets with Excellent Lithium Storage Performance.

Carbon layers-coated porous Co3O4/NiO (denoted as PCNO@C) chains are synthesized by the facile solvothermal method and subsequently annealing treatment under an Ar atmosphere, which are assembled from numerous Co3O4/NiO nanosheets. Benefiting from the unique porous chain structure, the volume change of the electrode is greatly relieved during the long-term cycling processes, and then an excellent cycling stability is obtained (the reversible specific capacity of the 1000th cycle can reach 637.3 mA h g-1 at 5000 mA g-1). Besides, a continuous conductive network is constructed by the coated carbon layers and long chains, the movement rate of electrons is effectively accelerated, and the high rate capability is obtained (the high reversible specific capacity of 480.6 mA h g-1 is retained at 10,000 mA g-1). This work contributes a new idea to construct porous chain structure anode materials.

Graphene Oxide-Wrapped Porous Hollow Co3O4 Microspheres with Enhanced Lithium Storage Performance.

Porous hollow Co3O4 microspheres wrapped with graphene oxide were synthesized by a step solvothermal method and subsequent heat treatment. Benefiting from the design of special porous hollow microspheres, the effective specific surface area was greatly increased, the sufficient contact between the porous hollow Co3O4 microspheres and electrolyte was achieved, and then a charge specific capacity of 888.59 mA h g-1 was gained. Meanwhile, partial stress from the charging/discharging process was greatly relieved due to the abundant pores and hollow structure, excellent cycling stability was realized, and the charge specific capacity of the 1000th cycle was 465.75 mA h g-1 at 5 C (1 C = 890 mA g-1). In addition, the conductivity of Co3O4 microspheres was effectively improved due to the tight package of graphene oxide to Co3O4 microspheres, and superior rate performance was attained (280.99 mA h g-1 at 10 C).

Graphene Oxide-Wrapped Co3O4/NiO Micron Flowers as an Anode of Lithium-Ion Batteries with Enhanced Rate Performance and Cycling Stability.

A graphene oxide-wrapped Co3O4/NiO (denoted as CNO/GO) micron flower is successfully synthesized by a rapid solvothermal method, which is formed through interpenetrating nanosheets. Nanosheets with a large specific surface area expose a large number of active sites for an electrochemical reaction. Moreover, abundant pores formed during the interpenetration of nanosheets are instrumental in providing enough buffer space to relieve the large volume expansion from the repeated lithium insertion/delithiation processes, and the tightly wrapped GO can effectively sustain the stability of the CNO micron flower structure during the long-term cycle processes. The reversible specific capacity as high as 602.9 mA h g-1 is maintained after 800 cycles at 5000 mA g-1. In addition, GO with good conductivity can greatly enhance the conductivity of CNO micron flowers, accelerate the transfer of electrons, and then achieve a high rate performance (the reversible specific capacity is 570.2 mA h g-1 at 10 000 mA g-1). This work provides a viable method for synthesizing the CNO micron flowers as a promising high-performance transition metal oxide anode for lithium-ion batteries.

IL-6 induced enhanced clearance of proANP and ANP by insulin-degrading enzyme in T1DM mice.

Cardiovascular disease (CVD) is a prevalent cause of morbidity and mortality in type I diabetes mellitus (T1DM). However, the pathophysiological mechanisms underlying the relationship between CVD, CVD risk factors, and T1DM have not yet been sufficiently explored. Here, we report that insulin-degrading enzyme (IDE) effectively degrades the precursor of atrial natriuretic peptide (proANP) in HEK293T cells. The pro-inflammatory cytokine IL-6 elicited a significant dose-dependent increase in IDE protein expression. Inhibition of the ERK/MAPK signaling pathway with selumetinib abolished the IL-6-stimulated increase in IDE protein levels and decreased ANP secretion in H9C2 cells. Importantly, the T1DM mouse model displayed lower proANP in the heart and ANP in serum, due to increased IDE expression and activity. Our results suggest a novel role of IL-6 in ANP metabolism via IDE and provide possibilities for new potential therapeutic strategies for diabetes-related cardiovascular complications.

Nix Mny Coz O Nanowire/CNT Composite Microspheres with 3D Interconnected Conductive Network Structure via Spray-Drying Method: A High-Capacity and Long-Cycle-Life Anode Material for Lithium-Ion Batteries.

The combination of high-capacity and long-term cycling stability is an important factor for practical application of anode materials for lithium-ion batteries. Herein, Nix Mny Coz O nanowire (x + y + z = 1)/carbon nanotube (CNT) composite microspheres with a 3D interconnected conductive network structure (3DICN-NCS) are prepared via a spray-drying method. The 3D interconnected conductive network structure can facilitate the penetration of electrolyte into the microspheres and provide excellent connectivity for rapid Li+ ion/electron transfer in the microspheres, thus greatly reducing the concentration polarization in the electrode. Additionally, the empty spaces among the nanowires in the network accommodate microsphere volume expansion associated with Li+ intercalation during the cycling process, which improves the cycling stability of the electrode. The CNTs distribute uniformly in the microspheres, which act as conductive frameworks to greatly improve the electrical conductivity of the microspheres. As expected, the prepared 3DICN-NCS demonstrates excellent electrochemical performance, showing a high capacity of 1277 mAh g-1 at 1 A g-1 after 2000 cycles and 790 mAh g-1 at 5 A g-1 after 1000 cycles. This work demonstrates a universal method to construct a 3D interconnected conductive network structure for anode materials.

Hollow TiNb2 O7 @C Spheres with Superior Rate Capability and Excellent Cycle Performance as Anode Material for Lithium-Ion Batteries.

TiNb2 O7 , with high charge/discharge voltage (1.65 V), long life span, and excellent reversibility has become a new anode material for lithium ion batteries in recent years. However, the inherent poor electronic conductivity strictly limits its practical applications. Herein, we report for the first time hollow TiNb2 O7 @C spheres, with carbon spheres as sacrificial template. The special hollow structure can effectively relieve the volume expansion during the repeated process of charging/discharging. The conductivity of hollow TiNb2 O7 spheres can be greatly improved by the carbon layers uniformly coated outside the surface of TiNb2 O7 spheres. Besides, the particle aggregation can be conspicuously suppressed by the uniformly coated carbon layers. As a result, hollow TiNb2 O7 @C spheres show a prominent charge/discharge capacity of 282.6/283.8 mAh g-1 after 100 cycles at 0.25 C (1 C=388 mA g-1 ), revealing the excellent cycle performance and high reversible capacity. Meanwhile, the charge/discharge capacity of 157.5 and 157.9 mAh g-1 can be maintained at 10 C after 10 cycles. The facial synthetic method can be extended to prepare various materials with volume expansion during repeated charging/discharging process.

Bonding and structure of a reconstructed (001) surface of SrTiO3 from TEM.

The determination of the atomic structure and the retrieval of information about reconstruction and bonding of metal oxide surfaces is challenging owing to the highly defective structure and insulating properties of these surfaces. Transmission electron microscopy (TEM) offers extremely high spatial resolution (less than one ångström) and the ability to provide systematic information from both real and reciprocal space. However, very few TEM studies have been carried out on surfaces because the information from the bulk dominates the very weak signals originating from surfaces. Here we report an experimental approach to extract surface information effectively from a thickness series of electron energy-loss spectra containing different weights of surface signals, using a wedge-shaped sample. Using the (001) surface of the technologically important compound strontium titanate, SrTiO(3) (refs 4-6), as a model system for validation, our method shows that surface spectra are sensitive to the atomic reconstruction and indicate bonding and crystal-field changes surrounding the surface Ti cations. Very good agreement can be achieved between the experimental surface spectra and crystal-field multiplet calculations based on the proposed atomic surface structure optimized by density functional calculations. The distorted TiO(6-x) units indicated by the proposed model can be viewed directly in our high-resolution scanning TEM images. We suggest that this approach be used as a general method to extract valuable spectroscopic information from surface atoms in parallel with high-resolution images in TEM.

Statistical Study of Beam-Induced Motion of Gold Adatoms by a Scanning TEM.

In order to achieve reliable structural characterization by transmission electron microscopy, beam-induced structural changes should be clarified for any target material system. As an example, the movement of heavy adatoms on a thin carbon support has been repeatedly reported under the electron beam while the underlying reason for such motion is still in debate. By applying statistical analysis to the group behavior of gold adatoms, we investigated their motion under different beam conditions and detected features corresponding to beam-induced motion, under typical scanning transmission electron microscopy observation conditions. Our results are consistent with the theoretical prediction proposed by Egerton (2013).

A "thickness series": weak signal extraction of ELNES in EELS spectra from surfaces.

We report a new simple but effective method to extract the weak surface signals from a "thickness series" of recorded electron energy-loss spectra. Using precise thickness measurements and energy-loss near-edge structures measured at increasing thicknesses, we are able to extract the surface and bulk components in the series. The electronic structure and bonding information from SrTiO3 (001) reconstructed surfaces have been successfully obtained by applying this approach. This approach can be applied to study many other cases including absorbed monolayers and beam-sensitive interfaces.

Intermedin protects against renal ischemia-reperfusion injury by inhibition of oxidative stress.

Reactive oxygen species (ROS) play a critical role in renal ischemia-reperfusion injury (IRI). Intermedin (IMD) reportedly protected against myocardial IRI via its antioxidant effects; however, its protective role in renal IRI has not been investigated. We overexpressed IMD in rat kidneys and examined how the kidneys respond to renal IRI. Eukaryotic expression plasmid encoding the rat IMD gene or control empty vector was transfected into the left kidney using an ultrasound-microbubble-mediated delivery system. This method yielded high expression of IMD in kidney cells. Renal IRI was induced by clamping the left renal artery followed by reperfusion. In response to IRI, overexpression of IMD in the kidney significantly improved renal function and pathology compared with the kidney transfected with control plasmid. We investigated the mechanisms by which IMD protects against renal IRI. We examined renal superoxide dismutase (SOD) activity and malondialdehyde (MDA) content and found SOD activity was significantly increased, while MDA level was markedly decreased in kidneys transfected with IMD, suggesting ROS production and oxidative stress were reduced by IMD overexpression. We also measured myeloperoxidase (MPO) activity, tubular cell apoptosis, and the expression of intercellular adhesion molecule-1 (ICAM-1), P-selectin, and endothelin-1 (ET-1) in the kidney. Renal MPO activity and the expression of ICAM-1, P-selectin, and ET-1 stimulated by IRI were significantly inhibited by IMD overexpression. Moreover, IMD overexpression prevented kidney cells from apoptosis caused by IRI. Our results demonstrate that overexpression of IMD in the kidney protects against renal IRI, apparently by reducing oxidative stress, consequently suppressing inflammation and vasoconstrictor production and apoptosis.

Atomic-level 2-dimensional chemical mapping and imaging of individual dopants in a phosphor crystal.

The ability to visualize and identify individual dopants, as well as measure their local physical and chemical environments in a bulk, provides deep insight for designing new functional materials and predicting their properties. However, a full understanding of dopants inside a solid has been limited by currently available characterization techniques. We demonstrate the first atomic-level 2-dimensional elemental maps of Pr dopants using the electron energy-loss spectroscopy (EELS) technique and we image Al dopants located in a lattice. Based on spectroscopic and imaging evidence we provide plausible local defect configurations of implanted Pr(+) and Al(+) ions within SrTiO3 single crystals. Our results demonstrate the detection of single Pr atoms and the formation of Al-rich nanoscale clusters ranging from 1 to 3 nm in size randomly distributed in the implanted lattice. These results provide insight into the mechanism of red light emission in doped SrTiO3.

Berberine ameliorates renal interstitial inflammation and fibrosis in mice with unilateral ureteral obstruction.

Berberine acts via multiple pathways to alleviate fibrosis in various tissues and shows renoprotective effects. However, its role and underlying mechanisms in renal fibrosis remain unclear. Herein, we aimed to investigate the protective effects and molecular mechanisms of berberine against unilateral ureteric obstruction-induced renal fibrosis. The results indicated that berberine treatment (50 mg/kg/day) markedly alleviated histopathological alterations, collagen deposition and inflammatory cell infiltration in kidney tissue and restored mouse renal function. Mechanistically, berberine intervention inhibited NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation and the levels of the inflammatory cytokine IL-1ß in the kidneys of unilateral ureteric obstruction mice. In addition, berberine relieved unilateral ureteric obstruction-induced renal injury by activating adenosine monophosphate-activated protein kinase (AMPK) signalling and promoting fatty acid ß-oxidation. In vitro models showed that berberine treatment prevented the TGF-ß1-induced profibrotic phenotype of hexokinase 2 (HK-2) cells, characterized by loss of an epithelial phenotype (alpha smooth muscle actin [α-SMA]) and acquisition of mesenchymal marker expression (E-cadherin), by restoring abnormal fatty acid ß-oxidation and upregulating the expression of the fatty acid ß-oxidation related-key enzymes or regulators (phosphorylated-AMPK, peroxisome proliferator activated receptor alpha [PPARα] and carnitine palmitoyltransferase 1A [CPT1A]). Collectively, berberine alleviated renal fibrosis by inhibiting NLRP3 inflammasome activation and protected tubular epithelial cells by reversing defective fatty acid ß-oxidation. Our findings might be exploited clinically to provide a potential novel therapeutic strategy for renal fibrosis.

Sawtooth Faceting in Rutile Nanowires.

Sawtooth faceting, with a diameter-dependent period, is pervasively observed in many Si, III-V, and II-VI nanowires during vapor-phase growth. This can be linked to an oscillation in surface energies, which are influenced by many factors such as crystal anisotropy, surface decoration, and twinning. Without the presence of surface decoration and planar defects, TiO2 rutile nanowires, axially oriented along a low-symmetry axis of ⟨110⟩, are promising to decouple the effect of crystal anisotropy from other factors. In this work, we synthesized ⟨110⟩ rutile nanowires, which exhibit complex periodic faceting consisting of {101} and {11̅0} facets. In addition to the expected linear width dependence, rutile nanowires, with the same width but different outward-inclined shapes, maintain the same period of their sawtooth faceting, as measured from TEM micrographs. In spite of different surface energy oscillations caused by different shapes, identical nucleation sites, which become energetically favorable during sawtooth growth, are predicted using thermodynamic models for nanowires with different shapes. This finding provides new insights into the morphological control of nanowires.

Nano/micrometer porous conductive network structure Li4Ti5O12@C/CNT microspheres with enhanced sodium-storage capability as an anode material.

Li4Ti5O12@C/CNT microspheres, wherein CNTs were firmly anchored to Li4Ti5O12@C nanoparticles, were prepared via a facile spray drying method and subsequently annealed in an argon atmosphere, exhibiting long cycling stability (charge/discharge capacities of 85.45/86.18 mA h g-1 after 500 cycles at 500 mA g-1) and excellent rate capability (charge capacity of 61.16 mA h g-1 after 10 cycles at 1000 mA g-1). The special spherical structure design is not only beneficial to improving the structural stability and reaction kinetics of the electrode materials during the long-term extraction-insertion of sodium ions but also supplies numerous interfacial sites to store more sodium ions.

Preparation and lithium storage of core-shell honeycomb-like Co3O4@C microspheres.

Core-shell honeycomb-like Co3O4@C microspheres were synthesized via a facile solvothermal method and subsequent annealing treatment under an argon atmosphere. Owing to the core-shell honeycomb-like structure, a long cycling life was achieved (a high reversible specific capacity of 318.9 mA h g-1 was maintained at 5C after 1000 cycles). Benefiting from the coated carbon layers, excellent rate capability was realized (a reversible specific capacity as high as 332.6 mA h g-1 was still retained at 10C). The design of core-shell honeycomb-like microspheres provides a new idea for the development of anode materials for high-performance lithium-ion batteries.

Ion beam-induced bending of TiO2 nanowires with bead-like and prismatic shapes.

Ion beam irradiation is a promising method to manipulate the composition and shape of nanowires. It causes the formation of crystal defects like vacancies and dislocations, and consequently, a volume expansion within the irradiated region, giving rise to the nanowire bending. The bending effect has been extensively discussed within nanowires with different diameters under ion beams with varying energies and ion fluences. However, the behaviors of nanowires with complicated shapes, which may have non-uniform irradiated regions due to the changing angle of incidence and shadowing effect, have remained largely unknown. Herein, the structural changes and bending of TiO2 nanowires with both bead-like and prismatic shapes are investigated under a Ga+ ion beam. The multi-faceted morphology, and consequently, varying angles of incidence, result in inhomogeneous irradiation and volume expansion. As a result, significant bending is only observed in prismatic nanowires. Since irradiation is confined within the half of nanowires facing the ion beam, the bending of nanowires is reversible by changing the direction of the ion beam. In order to provide insights into the tailoring composition and morphology of nanowires, we anticipate that this finding can establish the beam analog at the nanoscale, the bending of which can be tuned by ion irradiation.

Conductivity optimization via intertwined CNTs between TiNb2O7@C microspheres for a superior performance Li-ion battery anode.

Titanium niobate (TiNb2O7, TNO) possesses attractive discharge voltage and reversibility, which is considered to be an ideal anode material of lithium ion battery (LIB). However, its rate capability is strictly limited by their poor conductivity. To improve this issue faced by traditional TNO electrodes, a hierarchical conductive optimization strategy has been proposed and fabricated by a facile spray drying approach. For the construction, TiNb2O7@ultrathin carbon layer (TNO@C) is entangled into carbon nanotubes network to synthesize a highly conductive porous TNO@C/CNTs microsphere. This ultrathin carbon layer and evenly intertwined carbon nanotubes can ensure the superior charge transfer pathway, facilitating the transportation of electrons and Li ions. Additionally, CNTs can provide robust mechanical strength framework, beneficial to the structural stability of composite microspheres. As expected, the TNO@C/CNTs exhibits elevated conductivity and cyclic durability with charge capacities of 343.3 mAh·g-1 at 0.25 C after 300 cycles and 274.9 mAh·g-1 at 10 C after 1000 cycles. This study intends to explore the effect of the attached carbon materials on the TNO-based electrode conductivity and LIBs performances.

Coupling between the 2D "Ligand" and 2D "Host" and Their Assembled Hierarchical Heterostructures for Electromagnetic Wave Absorption.

Constructing the strong interaction between the matrix and the active centers dominates the design of high-performance electromagnetic wave (EMW) absorption materials. However, the interaction-relevant absorption mechanism is still unclear, and the design of ultrahigh reflection loss (RL < -80 dB) absorbers remains a great challenge. Herein, CoFe-based Prussian blue (PB) nanocubes are coprecipitated on the surface of ultrathin CoAl-LDH nanoplates with the assistance of unsaturated coordination sites. During the subsequent pyrolysis process, CoAl-LDH serves as a "ligand" providing a Co source and reacts with Fe or C in the CoFe-PB "host" to form stable CoFe alloys or CoCx species. As a result, strong reactions emerged between the CoAl-LDH matrix and the active CoFe-CoCx@NC centers. Based on the experimental results, the CoAl/CoFe-CoCx@NC hierarchical heterostructure delivers good dielectric losses (dipolar polarization, interface polarization, and conductive loss), magnetic losses (eddy current loss, natural resonance, and exchange resonance), and impedance matching, resulting in a remarkable EMW absorption performance with a reflection loss (RL) value of -82.1 dB at a matching thickness of 3.8 mm. Theoretical results (commercial CST) identify that the strong interaction between the 2D CoAl-LDH "ligand" and 2D CoFe-CoCx "host" promotes a robust heterointerface among the nanoparticles, nanosheets, and nanoplates, which extremely contribute to the dielectric loss. Meanwhile, the coupling effect of nanosheets and nanoplates greatly contributes to the matching performance. This work provides an aggressive strategy for the effect of ligands and hosts on high-performance EMW absorption.

Atomic overlayer of permeable microporous cuprous oxide on palladium promotes hydrogenation catalysis.

The interfacial sites of metal-support interface have been considered to be limited to the atomic region of metal/support perimeter, despite their high importance in catalysis. By using single-crystal surface and nanocrystal as model catalysts, we now demonstrate that the overgrowth of atomic-thick Cu2O on metal readily creates a two-dimensional (2D) microporous interface with Pd to enhance the hydrogenation catalysis. With the hydrogenation confined within the 2D Cu2O/Pd interface, the catalyst exhibits outstanding activity and selectivity in the semi-hydrogenation of alkynes. Alloying Cu(0) with Pd under the overlayer is the major contributor to the enhanced activity due to the electronic modulation to weaken the H adsorption. Moreover, the boundary or defective sites on the Cu2O overlayer can be passivated by terminal alkynes, reinforcing the chemical stability of Cu2O and thus the catalytic stability toward hydrogenation. The deep understanding allows us to extend the interfacial sites far beyond the metal/support perimeter and provide new vectors for catalyst optimization through 2D interface interaction.