Search

Because negative electrode of the neutral lead-carbon hybrid capacitor is composed by the active carbon and graphite, it is general believe that only the absorption-desorption process occurs in the negative electrode. However, in this work, we find that there is a second reaction going on the negative electrode: During charging, lead ions diffused from the positive electrode can be reduced to lead crystals when the charging cut-off voltage of the negative electrode is negative to the reduction potential of lead ions. These electrodeposited lead crystals can be converted into lead sulfate crystals during discharging, and these lead sulfate crystals cannot be completely dissolved in the next charging process. When lead sulfate crystals are accumulated on the surface of the carbon material gradually, the performance of the negative electrode is inhibited. Current densities have a great influence on this phenomenon because the charging cut-off voltage of the negative electrode is negatively shifted with the decrease of current density. The anion exchange membrane can completely inhibit this phenomenon by preventing the free diffusion of lead ions. After cycling at 2 A g−1 for 3400 times, the energy retention rate of the neutral lead-carbon hybrid capacitor increases from 34% to 81%.

Yttrium borides have attracted much attention for their superconducting and high chemical stability. However, the fundamental knowledge of the mechanical properties and hardness of yttrium borides is rather lack. Here, we performed a systematic investigation on yttrium borides with various stoichiometries based on an unbiased CALYPSO structure search method and first-principles calculations. A new YB6 compound with R3m hexagonal structure is observed, which is more stable than the experimental synthesized Pm3m phase. The calculated formation enthalpy, elastic constants, and phonon dispersions distinctly show that the R3m-YB6 is energetically, mechanically, and dynamically stable. The density of states and electronic band structure reveal that all the stable yttrium borides are metallic. Based on a semiempirical method, the Vicker hardness of R3m-YB6 is expectant to be 37.0 GPa, indicating it is a potential ultrahard metal. Our results provide insights for future synthesis and design of new type functional materials.

Since the discovery of metal-doped boron clusters attracted great significance to create a new class of materials, research interests have been directed to chemical bonding and structural evolution of lanthanide boride clusters. Here, we perform an extensive ground-state structure search for the CeBn and CeBn- clusters in the size range from 9 to 18 using the Crystal structure AnaLYsis by Particle Swarm Optimization method and density functional theory optimization. It is found that the ground-state structures in both neutral and anionic series possess half-sandwich geometry. The host boron moiety in neutral series has a tendency to form borophene-like geometry. The pentagonal and hexagonal holes are more common in the larger anionic CeBn- series. The theoretical photoelectron spectroscopy has been simulated by applying time-dependent density functional theory calculations. The neutral CeB14 cluster is identified as a magic cluster on the basis of its robust relative stability with respect to its neighbors. Electronic structure and chemical bonding analyses reveal that the CeB14 cluster possesses a large HOMO-LUMO gap and enhanced stability with strong delocalized π and δ bonding via interactions between the Ce 5d- and B 2p-AOs.

A simultaneous C2-H arylation and C8-H alkylation of naphthalene ring has been achieved by palladium-catalyzed cascade reaction of N-(2-halophenyl)-2-(naphthalen-1-yl)acrylamides with aryl iodides, which provides an efficient method for synthesizing various aryl-substituted spirocyclic oxindoles. The protocol enables three C C bonds formation via an intramolecular Heck reaction and sequentially regioselective C H bond activation.

On one hand, the construction of two fused five-membered carbocyclic rings remains an extremely challenging topic in organic synthesis. On the other hand, transition-metal-catalyzed dienyne cycloaddition reactions have become one of the most powerful methods for the construction of diverse cyclic frameworks. Nevertheless, these methods are limited to noble transition-meal catalysis and non-radical cycloaddition modes. Here, a radical Smiles rearrangement strategy for allowing an unprecedented [3 + 2]/[3 + 2] carboannulation of dienynes with arylsulfonyl chlorides using cheap copper catalysis is described. This cascade method represents a novel cycloaddition mode for dienyne chemistry, which occurs by the sequence of addition of arylsulfonyl radical to a dienyne, a Smiles rearrangement and radical annulation to access cyclopenta[a]indene-fused quinolinones with excellent diastereoselectivity.

This article presents a 250-GHz SiGe amplifier composed of three differential cascode stages in a 0.13- μ m SiGe BiCMOS technology ( f T/ f MAX = 300/500 GHz). The Marchand balun is utilized to implement single-ended to differential signal transformation for its superior performance over the transformer-based balun at sub-THz frequencies, which has been investigated and verified through electromagnetic (EM) simulations. A stair-like interconnection method and conventional positive feedback technique are used to improve the inherent gain of the active device. The proposed amplifier exhibits a record S21 of 21.5 dB at 252 GHz and a 3-dB bandwidth of 11 GHz with the capability of gain control. The measured OP 1dB is −3.7 dBm with the corresponding power added efficiency (PAE) of 0.3%, and the saturated output power is estimated to exceed 0 dBm at 252 GHz. The overall power consumption of the chip is 149 mW. Along with remarkable gain and output power, the compact amplifier is suitable to be adopted as an output block in the sub-THz transmitters.

The limitations of conventional organic liquid electrolytes such as sodium dendrite growth, serious side reactions, and liquid leakage hinder the development of sodium–metal batteries (SMBs). In th...

The aim of this study was to investigate the effects of mandibular advancement device (MAD) therapy for obstructive sleep apnea–hypopnea syndrome (OSAHS) on hypoxia-inducible factor-1α (HIF-1α), erythropoietin (EPO) and vascular endothelial growth factor (VEGF) in myocardial tissue. New Zealand rabbits were used to develop OSAHS and MAD models. Cone beam computed tomography (CBCT) of the upper airway and polysomnography (PSG) recordings were performed with the animals in the supine position. All of the animals were induced to sleep in a supine position for 4–6 h each day and were observed continuously for 8 weeks. The myocardial tissue of the three groups was dissected to measure the expression of HIF-1α, EPO and VEGF. The results showed that there was higher expression of HIF-1α, EPO and VEGF in the OSAHS group than those in the MAD and control groups. MAD treatment significantly downregulated the expression of HIF-1α, EPO and VEGF in the OSAHS animals. We concluded that MAD treatment could significantly downregulate the increased expression of HIF-1α, EPO and VEGF in OSAHS rabbits, improving their myocardial function.

Summary Maize exhibits marked growth and yield response to supplemental nitrogen (N). Here, we report the functional characterization of a maize NIN‐like protein ZmNLP5 as a central hub in a molecular network associated with N metabolism. Predominantly expressed and accumulated in roots and vascular tissues, ZmNLP5 was shown to rapidly respond to nitrate treatment. Under limited N supply, compared with that of wild‐type (WT) seedlings, the zmnlp5 mutant seedlings accumulated less nitrate and nitrite in the root tissues and ammonium in the shoot tissues. The zmnlp5 mutant plants accumulated less nitrogen than the WT plants in the ear leaves and seed kernels. Furthermore, the mutants carrying the transgenic ZmNLP5 cDNA fragment significantly increased the nitrate content in the root tissues compared with that of the zmnlp5 mutants. In the zmnlp5 mutant plants, loss of the ZmNLP5 function led to changes in expression for a significant number of genes involved in N signalling and metabolism. We further show that ZmNLP5 directly regulates the expression of nitrite reductase 1.1 (ZmNIR1.1) by binding to the nitrate‐responsive cis‐element at the 5′ UTR of the gene. Interestingly, a natural loss‐of‐function allele of ZmNLP5 in Mo17 conferred less N accumulation in the ear leaves and seed kernels resembling that of the zmnlp5 mutant plants. Our findings show that ZmNLP5 is involved in mediating the plant response to N in maize., Significance Statement In this study, we report the functional characterization of ZmNLP5 for its role in modulating the N response, suggesting that ZmNLP5 is a potential candidate for improving N use efficiency in maize production.

The chemoselective reaction remains a tremendous but particularly fascinating challenge in organic synthesis. Herein, we report a new domino Heck/disilylation reaction of alkene-tethered 2-(2-halophenyl)-1H-indoles with hexamethyldisilane under palladium catalysis. This procedure involving the formation of one C–C bond and two C–Si bonds proceeds efficiently through two key steps of the chemoselective Heck reaction and C–H activation by overcoming undesirable C3–H bond activation on the indoles, thus generating various disilylated tetracyclic indolo[2,1-a]isoquinolines in moderate to excellent yields. Furthermore, borylated indolo[2,1-a]isoquinolines can be produced by a Heck/borylation cascade.

Phospholipids in microvolume biofluid samples (≤0.5 μL), including human plasma and single cells, were selectively captured by dispersed magnetic Fe3O4@TiO2 nanocomposite particles (40 μg). A suspension containing Fe3O4@TiO2 nanoparticles was loaded into a glass capillary (i.d. 0.75 mm) by capillary force. The supernatant solution was discarded, while the Fe3O4@TiO2 particles were retained inside the capillary by using an external magnetic field (ca. 1.3 T). The phospholipids on the surface of Fe3O4@TiO2 nanoparticles were directly analyzed using internal extractive electrospray ionization mass spectrometry (iEESI-MS) by pumping ≤1 μL of extraction solution of methanol containing 1.5% ammonia (w/w) through the capillary tube toward the ESI tip. A single sample analysis was accomplished within 4 min. Phospholipids in blood plasma samples from 59 patients with ovarian cancer and 43 healthy controls, and 28 patients with pancreatic cancer and 23 healthy controls were studied. Based on the orthogonal partial least squares discriminant analysis (OPLS-DA), the cancer patients were confidently discriminated from the healthy controls. Phospholipids in single human cells (MV4-11 and NB4) were determined, showing the sensitivity for single cell analysis. Therefore the results demonstrated that rapid cancer differentiation is achieved using this approach through the detection of trace phospholipids in microvolume blood and cell samples with high sensitivity, high specificity, low sample consumption, and high throughput.

A palladium-catalyzed three-component tandem reaction for stereoselective assembly of various tri- or tetrasubstituted vinylsilanes is established. This method enables the construction of two C–Si bonds and two C–C bonds by the disilylation of ortho-vinyl bromobenzenes generated in situ from 1-bromo-2-iodobenzenes and N-tosylhydrazones. More importantly, the substrate scope of this protocol was further demonstrated by the transformation of ortho-vinyl bromobenzenes generated from a range of aryl iodides and N-tosylhydrazone to vinylsilanes.

A new palladium-catalyzed tandem cyclization of various alkene-tethered aryl iodides has been presented. In this protocol, o-bromobenzoic acids are employed as coupling parters to achieve the insertion of aromatic rings by the cleavage of C(sp2)-Br and decarboxylation, thus assembling various dibenzoisoquinolinediones and dibenzoisoquinolinones. In addition, a seven-membered ring can be constructed by the use of 8-bromo-1-naphthoic acid. Notably, this approach enables regioselective product formation and features broad substrate scope.

The rapid and direct structural characterization of lipids proves to be critical for studying the functional roles of lipids in many biological processes. Among numerous analytical techniques, ambient ionization mass spectrometry (AIMS) allows for a direct molecular characterization of lipids from various complex biological samples with no/minimal sample pretreatment. Over the recent years, researchers have expanded the applications of the AIMS techniques to lipid structural elucidation via a combination with a series of derivatization strategies (e.g., the Paternò–Büchi (PB) reaction, ozone-induced dissociation (OzID), and epoxidation reaction), including carbon–carbon double bond (C=C) locations and sn-positions isomers. Herein, this review summarizes the reaction mechanisms of various derivatization strategies for C=C bond analysis, typical instrumental setup, and applications of AIMS in the structural elucidation of lipids from various biological samples (e.g., tissues, cells, and biofluids). In addition, future directions of AIMS for lipid structural elucidation are discussed.

The wide application of nano-particles (NPs) has raised a serious concern over their impact on plants. However, evaluation of the effects of NPs on plant metabolism by direct detection of chemicals inside solid tissues presents a challenge. In this study, we report on a direct ionization method in mass spectrometry, internal extractive electrospray ionization (iEESI), for the direct evaluation of phytotoxicity of three different NPs (including CdTe quantum dots (CdTe QDs), gold nano-particles (Au NPs), and silver nano-particles (Ag NPs)) both on surfaces and inside solid tissues from the mung bean seeds (Vigna radiata) that were cultured in aqueous solutions of three NPs at 50 μg mL−1. The results showed that NPs could stimulate the biological accumulation of trigonelline and the decomposition of polysaccharides/oligosaccharides to glucose and maltose within 21 h of culture. To the best of our knowledge, this is the first study to apply internal extractive electrospray ionization mass spectrometry (iEESI-MS) for the direct measurement of solid tissue samples to evaluate the phytotoxicity of NPs on mung bean sprouts. Our study lays a solid foundation for further examination of other NPs-induced damaging effects such as apoptosis/necrosis, helping us to understand the phytotoxicity of NPs on plants.

Background: To examine the morphology and function of mitochondria from the genioglossus in a rabbit model of obstructive sleep apnea-hypopnea syndrome (OSAHS), as well as these factors after insertion of a mandibular advancement device (MAD). Methods: Thirty male New Zealand white rabbits were randomized into three groups: control, OSAHS and MAD, with 10 rabbits in each group. Animals in Group OSAHS and Group MAD were induced to develop OSAHS by injection of gel into the submucosal muscular layer of the soft palate. The rabbits in Group MAD were fitted with a MAD. The animals in the control group were not treated. Further, polysomnography (PSG) and CBCT scan were used to measure MAD effectiveness. CBCT of the upper airway and PSG suggested that MAD was effective. Rabbits in the three groups were induced to sleep for 4–6 hours per day for 8 consecutive weeks. The genioglossus was harvested and detected by optical microscopy and transmission electron microscopy. The mitochondrial membrane potential was determined by laser confocal microscopy and flow cytometry. Mitochondrial complex I and IV activities were detected by mitochondrial complex assay kits.Results: OSAHS-like symptoms were induced successfully in Group OSAHS and rescued by MAD treatment. The relative values of the mitochondrial membrane potential, mitochondrial complex I activity and complex IV activity were significantly lower in Group OSAHS than in the control group; however, there was no significant difference between Group MAD and the control group. The OSAHS-induced injury and the dysfunctional mitochondria of the genioglossus muscle were reduced by MAD treatment.Conclusion: Damaged mitochondrial structure and function were induced by OSAHS and could be attenuated by MAD treatment.

Herein, a readily available disilane Me3SiSiMe2(OnBu) has been developed for the synthesis of diverse silacycles via Brook- and retro-Brook-type rearrangement. This protocol enables the incorporation of a silylene into different starting materials, including acrylamides, alkene-tethered 2-(2-iodophenyl)-1H-indoles, and 2-iodobiaryls, via the cleavage of Si–Si, Si–C, and Si–O bonds, leading to the formation of spirobenzosiloles, fused benzosiloles, and π-conjugated dibenzosiloles in moderate to good yields. Preliminary mechanistic studies indicate that this transformation is realized by successive palladium-catalyzed bis-silylation and Brook- and retro-Brook-type rearrangement of silane-tethered silanols., A readily available disilane Me3SiSiMe2(OnBu) as a silylene source has been developed for the synthesis of diverse silacycles via Brook- and retro-Brook-type rearrangement.

Exploring the metabolic disturbance of fipronil and its derivatives in aquatic organisms may provide a more comprehensive understanding of the impact of fipronil on the ecological environment. In this work, internal extractive electrospray ionization mass spectrometry (iEESI-MS) was used to directly analyze metabolites in the liver tissue of zebrafish exposed to fipronil and its three derivatives. Partial least squares-discriminant analysis (PLS-DA) revealed that 32 signals were considered as differential signals in zebrafish after the exposure treatment of fipronil and its derivatives, including phosphatidylcholines (PCs), lysophosphatidylcholines (LPCs), phosphatidylethanolamines (PEs), fatty acids and so on. The pathway analysis result showed that both fipronil and its derivatives have a significant impact on the glycerophospholipid metabolism of zebrafish. Besides, the intensities of PC signals in the liver samples of each group showed such a trend: mixed fiprole exposed group > fipronil sulfone exposed group ≈ fipronil sulfide exposed group > fipronil exposed group > fipronil desulfinyl exposed group > control group, indicating that mixed exposure of fipronil and its derivatives exhibited more significant metabolic disturbance in zebrafish. Taken together, iEESI-MS is applied to environmental toxicology and investigating the metabolic disturbance induced by fipronil and its derivatives in aquatic organisms, providing a new analytical method for this field.

A novel palladium-catalyzed cascade cyclization of alkene-tethered aryl halides with o-bromobenzoic acids is described, which provides an efficient avenue for building various fused hexacyclic scaf...

Traditionally, molecular information on metabolites, lipids, and proteins is collected from separate individual tissue samples using different analytical approaches. Herein a novel strategy to minimize the potential material losses and the mismatch between metabolomics, lipidomics, and proteomics data has been demonstrated based on internal extractive electrospray ionization mass spectrometry (iEESI-MS). Sequential detection of lipids, metabolites, and proteins from the same tissue sample was achieved without sample reloading and hardware alteration to MS instrument by sequentially using extraction solutions with different chemical compositions. With respect to the individual compound class analysis, the sensitivity, specificity, and accuracy obtained with the integrative information on metabolites, lipids, and proteins from 57 samples of 13 patients for lung cancer prediction was substantially improved from 54.0%, 51.0%, and 76.0% to 100.0%, respectively. The established method is featured by low sample consumption (ca. 2.0 mg) and easy operation, which is important to minimize systematic errors in precision molecular diagnosis and systems biology studies.

Polyaniline hollow nanofibers (PANI-HNFs) are successfully synthesized by using poly (methyl methacrylate) nanofibers as a sacrifice-template via an in-situ polymerization with a subsequent dissolution process. The polyaniline hollow nanofibers as cathode material for sodium-ion batteries exhibit a high reversible capacity of 153 mA h g−1 at 0.3 C (1C = 150 mA g−1), high cycling stability (73.3% capacity retention after 1000 cycles) and rate capability (70 mA h g−1 at 8 C). The high electrochemical performance of the polyaniline hollow nanofibers originates from the one dimension hollow nanostructures with unique morphologies and highly reversible doping/dedoping property of the conducting polymer, so as to ensure well structural stability and good electrical/ionic conducting connectivity. Furthermore, this strategy can controllably prepare various hollow one dimension structures with different tube diameters and wall sizes, which has potential application for energy storage materials, catalysts, drug-delivered materials and chemical microreactors.

A pyrolyzed subbituminous carbon is synthesized through a simple one-step carbonization process as low-cost and high-capacity anode for sodium-ion batteries (SIB). The pyrolyzed subbituminous carbon, SHC-1300 anode shows high Na storage capacity of 291 mA h g–1 at 20 mA g–1 and high initial Coulombic efficiency of 79.5%, as well as stable cycling performance, exhibiting a promising alternative anode for affordable and high-performance SIB. Furthermore, according to the investigation of the electrochemical performance and structural characterizations, the SHC-1300 pyrolyzed from subbituminous coal with flexible structure demonstrates a better electrochemical performance compared with the BHC-1300 pyrolyzed from bituminous coal with rigid structure. The sodium storage mechanism and structural evolution reported in this work may give a new prospect for the selection of pyrolyzed carbon materials for high-performance sodium-ion batteries.

Hard carbons are actively developed as a promising anode material for sodium ion batteries (SIBs). However, their sodium storage mechanism is poorly understood, leading to difficulties in design and development of high-performance hard carbon anode materials. In this work, hollow carbon spheres (HCSs) with different shell thickness as a model material to investigate the correlation between the microstructural change and resulting Na+ storage behavior during charge/discharge cycles are designed and synthesized. Ex situ X-ray diffraction and Raman evidences reveal that an interlayer spacing change of the graphitic nanodomains occurs in HCS electrode, leading to a shift of the reversible capacity from the high-potential sloping (HPS) region to the low-potential plateau (LPP) region. This unusual capacity shift suggests a microstructure-dependent Na+ storage reaction on the HCS electrode and can be well explained by "adsorption-intercalation" mechanism for these HCS materials. This work strengthens the understanding of the sodium storage behavior and provides a new perspective for the morphological and structural design of hard carbon anode materials for high-performance SIBs.

Hard carbon (HC) has been actively investigated as a high-capacity and low-cost anode material for sodium-ion batteries (SIBs); however, its sodium-storage mechanism has remained controversial, which imposes great difficulties in the design and construction of better microstructured HC materials. To obtain a deeper understanding of the Na-storage mechanism, we comparatively investigated electrochemical behaviors of HC and graphite for Na- and Li-storage reactions. The experimental results reveal that the Na-storage reaction on HC at a low-potential plateau proceeds in a manner similar to the Li+-insertion reaction on graphite but very differently from the Li+-storage process on HC, suggesting that the Na-storage mechanism of HC at a low-voltage plateau operates through the Na+ intercalation into the graphitic layers for the formation of sodium-graphite intercalation compounds (Na-GICs) and is consistent with the "adsorption-intercalation" mechanism. Our work might provide new insight for designing better HC materials of high-energy density SIBs.

Direct molecular analysis of tissue samples is a promising approach to increase the accuracy, speed and molecular specificity of cancer diagnosis. Herein, alterations of amino acids between human lung cancer tissues and matched adjacent normal tissues were profiled by internal extraction electrospray ionization mass spectrometry (iEESI-MS). The results indicated that the levels of 11 detected amino acids (including serine, proline, valine, threonine, asparagine, aspartic acid, methionine, histidine, phenylalanine, arginine and tyrosine) in the cancerous tissues were lower than that in the adjacent normal tissues. Based on the orthogonal partial least squares discriminant analysis (OPLS-DA) model, cancerous and adjacent normal tissues were clearly discriminated, and the amino acids that played the major role in the differentiation between cancerous and adjacent normal tissues were identified. Moreover, metabolic pathway analysis revealed alterations of differential amino acids in several metabolic pathways upon lung cancer. The current study extends the power of iEESI-MS as a promising tool for quantitative characterization of amino acids in tissues, and allows the study of alterations in amino acids metabolism associated with the development of lung cancer.

Leptin, an adipocyte-derived peptide hormone, has been shown to facilitate breathing. However, the central sites and circuit mechanisms underlying the respiratory effects of leptin remain incompletely understood. The present study aimed to address whether neurons expressing leptin receptor b (LepRb) in the nucleus tractus solitarii (NTS) contribute to respiratory control. Both chemogenetic and optogenetic stimulation of LepRb-expressing NTS (NTS(LepRb)) neurons notably activated breathing. Moreover, stimulation of NTS(LepRb) neurons projecting to the lateral parabrachial nucleus (LPBN) not only remarkably increased basal ventilation to a level similar to that of the stimulation of all NTS(LepRb) neurons, but also activated LPBN neurons projecting to the preBötzinger complex (preBötC). By contrast, ablation of NTS(LepRb) neurons projecting to the LPBN notably eliminated the enhanced respiratory effect induced by NTS(LepRb) neuron stimulation. In brainstem slices, bath application of leptin rapidly depolarized the membrane potential, increased the spontaneous firing rate, and accelerated the Ca(2+) transients in most NTS(LepRb) neurons. Therefore, leptin potentiates breathing in the NTS most likely via an NTS–LPBN–preBötC circuit.

Bolin Li,1 Chunyan Liu,2,3 Ze-hui Fang,4 Ying Cao,4 Zheng Zhou,3 Haiyan Lu2 1Hebei Key Laboratory of Stomatology, Hebei Clinical Research Center for Oral Diseases, School & Hospital of Stomatology, Hebei Medical University, Shijiazhuang 050017, People’s Republic of China; 2Department of Orthodontics, Hebei Key Laboratory of Stomatology, Hebei Clinical Research Center for Oral Diseases, School & Hospital of Stomatology, Hebei Medical University, Shijiazhuang 050017, People’s Republic of China; 3School of Dentistry, University of Detroit Mercy, Detroit, Michigan 48208, USA; 4School & Hospital of Stomatology, Anhui Medical University, Hefei 230032, People’s Republic of ChinaCorrespondence: Zheng ZhouSchool of Dentistry, University of Detroit Mercy, 2700 Martin Luther King Jr. Blvd, Detroit, Michigan 48208, USATel +1-313-494-6667Fax +1-313-494-6666Email zhouzh1@udmercy.eduHaiyan LuDepartment of Orthodontics, Hebei Key Laboratory of Stomatology, Hebei Clinical Research Center for Oral Diseases, School & Hospital of Stomatology, Hebei Medical University, 383 Zhongshan East Road, Shijiazhuang, Hebei 050017, People’s Republic of ChinaTel/Fax +86 311-86265748Email luhaiyan67@163.comBackground: Dentin hypersensitivity (DH) is a common dental clinical condition presented with a short and sharp pain in response to physical and chemical stimuli. Currently no treatment regimen demonstrates long-lasting efficacy in treating DH, and unesthetic yellow tooth color is a concern to many patients with DH.Aim: To develop a bi-functional material which can occlude dentinal tubules in-depth and remineralize dentin for long-lasting protection of the dentin–pulp complex from stimuli and bleach the tooth at the same time.Methods: A mixture containing CaO, H3PO4, polyethylene glycol and H2O2 at a specific ratio was mechanically ground using a planetary ball. The mineralizing complex paste was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Dentin was exposed to the synthesized paste for 8 h and 24 h in vitro. The mineralizing property was evaluated using SEM and microhardness tests. Red tea-stained tooth slices were exposed to the synthesized paste for 8 h and 24 h in vitro. The bleaching effect was characterized by a spectrophotometer.Results: The complex paste had very a fine texture, was injectable, and had a gel-like property with 2.6 (mass/volume) % H2O2 concentration. The X-ray diffraction pattern showed that the inorganic phase was mainly monetite (CaHPO4). The mineralizing complex paste induced the growth of inorganic crystals on the dentin surface and in-depth occlusion of dentin tubules by up to 80 μm. The regenerated crystals were integrated into the dentin tissue on the dentin surface and the wall of dentinal tubules with a microhardness of up to 126 MPa (versus 137 Mpa for dentin). The paste also bleached the stained dental slices.Conclusion: The mineralizing complex paste is a promising innovative material for efficient DH management by remineralizing dentin and in-depth occlusion of dentin tubules, as well as tooth bleaching.Keywords: dentin hypersensitivity, remineralization, tooth whitening, planetary ball mill

Methane emitted by insects is considered to be an important source of atmospheric methane. Here we report the stimulation of methane emission in Periplaneta americana, an insect species with abundant methanogens, by neonicotinoids, insecticides widely used to control insect pests. The application of cycloxaprid (CYC) and imidacloprid (IMI) caused foregut expansion in P. americana, and increased the methane production and emission. Antibiotics could mostly eliminate the stimulatory effects. In P. americana gut, hydrogen levels increased and pH values decreased, which could be significantly explained by the gut bacterium community change. The proportion of several bacterium genera increased in guts following CYC treatment, and four genera from five with increased proportions could generate hydrogen at anaerobic conditions. Hydrogen is a central intermediate in methanogenesis. Gut methanogens could use the increased hydrogen to produce more methane, especially at acidic conditions. Following neonicotinoid applications, all increased methanogens in both foregut and hindgut used hydrogen as electron donor to produce methane. Besides, the up-regulation of mcrA, encoding the enzyme that catalyzes the final step of methanogenesis, suggested an enhanced methane production ability in present methanogens. In the termite Coptotermes chaohuensis, another methanogen-abundant insect species, hydrogen levels in gut and methane emission significantly increased after neonicotinoid treatment, which was similar to the results in P. americana. In summary, neonicotinoids changed bacterium community in P. americana gut to generate more hydrogen, which then stimulate gut methanogens to produce and emit more methane. The finding raised a new concern over neonicotinoid applications, and might be a potential environmental risk associated with global warming.

Comparative studies of molecular alterations upon cancer between mice and humans are of great importance in order to determine the relevance of research involving mouse cancer models to the development of diagnostic and therapeutic approaches in clinical practice as well as for the mechanistic studies of pathology in humans. Herein, using molecular fingerprinting by internal extractive electrospray ionization mass spectrometry (iEESI-MS), we identified 50 differential signals in mouse liver tissue and 62 differential signals in human liver tissue that undergo significant intensity alterations (variable importance in the project (VIP) >1.0) upon liver cancer, out of which only 27 were common in both mouse and human tissues. Out of the 27 common differential signals, six types of phospholipids were also identified to undergo significant alterations in human serum upon liver cancer, including PC(34:2), PC(36:4), PC(38:6), PC(36:2), PC(38:4) and PC(42:9). Statistical analysis of the relative intensity distribution of these six identified phospholipids in serum allowed confident determination of liver cancer in humans (sensitivity 91.0%, specificity 88.0%, and accuracy 90.0%). Our results indicate that, despite the significant difference in the overall alterations of phospholipid profiles upon liver cancer between humans and mice, the six identified 'core' differential phospholipids of liver cancer found in the liver tissues of both humans and mice as well as in human serum show high potential as a minimal panel for the rapid targeted diagnosis of liver cancer with high accuracy, sensitivity and specificity using direct mass spectrometry (MS) analysis.

A combination of the density functional theory and the single-site dynamical mean-field theory is employed to study the electronic structures of various allotropes of elemental curium (Cm-I, Cm-II, and Cm-III). We find that the 5$f$ valence electrons in the high-symmetry Cm-I and Cm-II phases remain localized, while they turn into itinerancy in the low-symmetry monoclinic Cm-III phase. In addition, conspicuous quasiparticle multiplets are identified in the 5$f$ electronic density of states of the Cm-III phase. We believe that it is the many-body transition between $5f^{7}$ and $5f^{8}$ configurations that gives rise to these quasiparticle multiplets. Therefore, the Cm-III phase is probably a new realization of the so-called Racah metal., 7 pages, 4 figures

Electrolytes as an important part of sodium-ion batteries have a pivotal role for capacity, rate, and durability of electrode materials. On account of the high reduction activity of sodium metal with organic solvents, it is very important to optimize the electrolyte component to realize high stability on Na metal and hard carbon anodes. Herein, chemical and electrochemical stability of propylene carbonate (PC)-based electrolytes on sodium metal and hard carbon anodes is investigated systematically. The results demonstrate that whether using NaClO4 or NaPF6, the PC-based electrolytes are not stable on Na metal, but adding of FEC can immensely enhance the stability of the electrolyte because of the compact solid electrolyte interphase film formed. The electrolytes containing FEC also exhibit high electrochemical compatibility on hard carbon anodes, showing high reversible capacity and excellent cycling performance. A reaction mechanism based on the Na+ induction effect is proposed by spectrum and electrochemical measurements. This study can provide a new insight to optimize and develop stable PC-based electrolytes and be helpful for understanding the other electrolyte systems.

Rapid analysis of phosphopeptides and phospholipids in biological matrixes is of significant interest in multiple disciplines of life sciences. Herein, trace phospholipids in human plasma, whole blood, and undiluted human urine as well as phosphopeptides in protein digest were selectively captured on a homemade array of TiO2 nanowires for sensitive characterization by internal extractive electrospray ionization mass spectrometry (TiO2-iEESI-MS). Sequential release of captured chemicals from TiO2 array was achieved by tuning pH of the extraction solvent. A single sample analysis, including sample loading, chemical extraction and MS detection, was accomplished within 3 min. As far as the quantification of phospholipids, acceptable linearity (R2 ≥ 0.9985) and relative standard deviations (RSDs ≤ 8.9%) were obtained within the range of 0.1–500 μg L–1 for LysoPC(14:0) and LysoPC(16:0) in raw urine samples. Limit of detection (LOD) ≤ 0.025 μg L–1 and recovery rates of 94.8–101.6% were obtained for these phospho...

In this paper, we present the first millimeter-wave GaN HEMT monolithic integrated circuit (MMIC) amplifier with an operating frequency at 220 GHz. This MMIC has a small-signal gain well above 11 dB at 222 GHz. Moreover, the use of gallium nitride technology allows for achieving state-of-the-art saturated output power, up to 14dBm at 222 GHz. To our knowledge, the measured gain and output power levels are the best among any of the GaN MMICs beyond 200 GHz reported to date.

In this report, a hierarchical porous carbon microtubes (CMTs) coated by carbon skeleton was prepared simply and the better role of carbon skeleton in increasing the capacity of CMTs was also investigated. SEM, XRD and XPS were used to character the morphology, crystal structure and the functional group of CMTs and CMTs-coated carbon skeleton. Electrochemistry of materials was conducted by CV and constant-current techniques. The results show that the carbon skeleton improves the electric conductivity of materials and thus a better stability of capacity during charge and discharge was obtained (from 81.2 to 97.1% of original specific capacitance after 10000 GCD cycles at 1 A g−1), although the high specific surface area were altered weakly (1159 m2 g−1). Besides, the incorporated nitrogen-containing functional group can increase the gravimetric capacitance of materials from 253 F g−1 to 278 F g−1, with the volumetric capacitance up to 152 F cm−3. The adequate utilization of nature characteristic of biomass and the simple synthesis of stable carbon skeleton offers a good alternative route for advance CMTs.

β-Glucosidase was selected to be a reporter to study metabolic burden imposed by its expression in yeast. Cell growth, fermentation yield and enzymatic activity were used as indicators of the metabolic burden borne by 14 recombinant yeast strains. Various factors were found to affect metabolic burden, including BGLI gene source, gene dose, trafficking of the enzyme (either cell-surface display or secretion), and oxygen supply. While BGLI gene from Aspergillus aculeatus provided better performance for the host cells than that from Saccharomycopsis fibuligera, displaying β-glucosidase on the cell surface generally led to lower μm, total activity and ethanol titer, and longer lag period, lower (aerobic condition) or higher (anaerobic condition) biomass yield than that of secreting β-glucosidase. The negative effect on growth increased with gene dose level until a final failure to grow. This growth difference implies that displaying β-glucosidase on the cell surface imposes an extra metabolic burden. The molecular basis and mechanisms for this phenomenon need to further be investigated in order to develop better strategies for utilizing displayed and secreted enzymes in biotechnology and yeast breeding.

In this paper, a new 3-D electromagnetic (EM) simulation approach for heterojunction bipolar transistor (HBT) parameter extraction in terahertz band is presented. We introduce an inter-electrode impedance equivalent-circuit model with the concept of dispersive parameters and a more rigorous 3-D EM simulation parameter extraction method to avoid serious discrepancies between the simulated EM field distribution and the real EM field distribution of the device. Terahertz parasitic effects, including the EM field discretization and multi-finger device field sharing, are observed. Compared with the previous 3-D EM simulation-assisted model, the new model in this paper demonstrates better results for multi-finger indium phosphide HBTs.

Background Porphyromonas gingivalis (P. gingivalis) is considered to be among the principal pathogens in periodontal disease. The present study aimed to investigate the effect of antimicrobial photodynamic therapy (aPDT) mediated by cationic amino acid-porphyrin conjugate 4i on P. gingivalis Methods The uptake of 4i by P. gingivalis over different times of incubation was evaluated by optical density using a microplate reader. Laser radiation at λ=650nm-660nm with I =50 mW/cm2 at doses of 0, 3.0, 6.0, 9.0, and 12 J/cm2 was used for aPDT. A colony-counting method and confocal laser scanning microscopy (CLSM) were used to observe the neutralization of P. gingivalis. The fluorescent molecular probe 3’(p-hydroxyphenyl)-fluorescein and the reagent Singlet Oxygen Sensor Green were used to measure the quantities of •OH and 1O2 produced by 4i after irradiation with different light energies. Results The 4i conjugate was absorbed gradually by P. gingivalis, reaching a maximum at 30 min. A clear cytotoxic effect on P. gingivalis was observed with aPDT using 62.5 µM 4i, with colony counts dropping by a factor of 3.35 log10, indicating a sterilization rate of 99.95%. Light irradiation resulted principally in the production of • OHby 4i. A live/dead viability assay demonstrated substantial red fluorescence in P. gingivalis treated with aPDT. Conclusions The results suggest that 4i-aPDT caused substantial cytotoxicity in P. gingivalis.

This paper presents an accurate quasi-physical compact large-signal model for GaN high electron mobility transistors (HEMTs). The drain current $I_{\mathrm {ds}}$ expression is acquired by combining the zone division method and the surface potential theory. The proposed $I_{\mathrm {ds}}$ model only contains 19 empirical parameters, with self-heating, ambient temperature and trapping effects considered. The self-heating effects are modeled by a polynomial function of temperature and gate voltage for the critical electric field $E_{c}$ . And the ambient temperature effects are modeled by modifying pinchoff voltage and maximal electron saturated velocity. The trapping effects are considered with an effective gate–source voltage method. Moreover, taking the advantage of good physical meaning, the proposed $I_{\mathrm {ds}}$ model is scalable. In house 0.15- $\mu \text{m}$ GaN HEMTs with different sizes are used to validate the model by dc $I$ – $V$ over a wide ambient temperature range, pulsed $I$ – $V$ , multibias S-parameters up to 50 GHz and multibias large-signal characteristics at $f_{0} = 30$ GHz. The good results show that the proposed quasi-physical zone division model is useful for millimeter-wave GaN HEMTs development and circuit design.

There has been an increasing number of studies on the interaction between active substances and probiotics to improve disease. Both krill oil (KO) and probiotics have the effect of improving atherosclerotic cardiovascular disease, but the combined effect has not been explored. Therefore, the purpose of this study was to explore the improvement effect of KO combined with probiotics on atherosclerosis. The atherosclerotic plaque area of ApoE−/− mice was detected after the intervention of KO, Bifidobacterium animalis subsp. lactis F1-7 (Bif. animalis F1-7), and KO combined with Bif. animalis F1-7. The results showed that Bif. animalis F1-7, KO, and KO combined with Bif. animalis F1-7 could significantly reduce the area of atherosclerotic plaque and improve the levels of serum lipids and inflammatory factors. They could regulate the farnesoid X receptor (FXR)/cholesterol 7-alpha hydroxylase (CYP7A1) pathway to reduce lipid accumulation. The intervention groups could also improve the inflammatory response by downregulating the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88) pathway. The anti-inflammatory effect of the interaction group was significantly better than that of KO. It proved that Bif. animalis F1-7 might play a synergistic effect in the improvement of inflammation by KO to the alleviation of atherosclerosis.

Methane emitted by insects is considered to be an important source of atmospheric methane. Here we report the stimulation of methane emission in the cockroach Periplaneta americana and termite Coptotermes chaohuensis, insects with abundant methanogens, by neonicotinoids, insecticides widely used to control insect pests. Cycloxaprid (CYC) and imidacloprid (IMI) caused foregut expansion in P. americana, and increased the methane emission. Antibiotics mostly eliminated the effects. In P. americana guts, hydrogen levels increased and pH values decreased, which could be significantly explained by the gut bacterium community change. The proportion of several bacterium genera increased in guts following CYC treatment, and two genera from four could generate hydrogen. Hydrogen is a central intermediate in methanogenesis. All increased methanogens in both foregut and hindgut used hydrogen as electron donor to produce methane. Besides, the up-regulation of mcrA, encoding the enzyme for the final step of methanogenesis suggested the enhanced methane production ability in present methanogens. In the termite, hydrogen levels in gut and methane emission also significantly increased after neonicotinoid treatment, which was similar to the results in P. americana. In summary, neonicotinoids changed bacterium community in P. americana gut to generate more hydrogen, which then stimulated gut methanogens to produce and emit more methane. The finding raised a new concern over neonicotinoid applications, and might be a potential environmental risk associated with atmospheric methane.

Objective To investigate effects of mandible advanced device (MAD) therapy for obstructive sleep apnoea-hypopnea syndrome (OSAHS) on the neuron apoptosis and acetylcholine esterase activity in frontal cortex. Materials and methods Thirty male New Zealand white rabbits were randomly divided into three groups (n = 10 in each group): group OSAHS, group MAD, and control group. Hydrophilic polyacrylamide gel was injected into soft palate of the animals to induce OSAHS in group OSAHS and group MAD. The group MAD animals wore MAD to relief the obstructiveness. The control group was not given any treatment. Computed tomography (CT) examination of the upper airway and polysomnography (PSG) recordings were performed in supine position. All rabbits were induced to sleep in a supine position for 4 to 6 hours every day and were observed for consecutive 8 weeks. The frontal cortices of three groups were dissected and the neuron apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and flow cytometry. Acetylcholine esterase (AchE) activity in the frontal cortex was measured by spectrophotometry. Results The group OSAHS exhibited high neuron apoptosis rate and low AchE activity than those of group MAD and control group. The blood oxygen saturation was negatively correlated with neuronal apoptosis rate and positively correlated with AchE activity. Applying MAD in OSAHS animals significantly improve the neuronal damage and function deficits by apnoea-hypoxia caused by narrowed upper airway. Conclusion This study provided evidence that MAD therapy for OSAHS can significantly decrease neuronal apoptosis and increase AchE activity in the frontal cortex.