A new Mn-based layered cathode with enlarged interlayer spacing for potassium ion batteries.

Layered Mn-based cathode (KxMnO2) has attracted wide attention for potassium ion batteries (PIBs) because of its high specific capacity and energy density. However, the structure and capacity of KxMnO2 cathode are constantly degraded during the cycling due to the strong Jahn-Teller effect of Mn3+ and huge ionic radius of K+. In this work, lithium ion and interlayer water were introduced into Mn layer and K layer in order to suppress the Jahn-Teller effect and expand interlayer spacing, respectively, thus obtaining new types of K0.4Mn1-xLixO2·0.33H2O cathode materials. The interlayer spacing of the K0.4MnO2 increased from 6.34 to 6.93 Å after the interlayer water insertion. X-ray photoelectron spectroscopy studies demonstrated that proper lithium doping can effectively control the ratio of Mn3+/Mn4+ and inhibit the Jahn-Teller effect. In-situ X-ray diffraction exhibited that lithium doping can inhibit the irreversible phase transition and improve the structural stability of materials during cycling. As a result, the optimal K0.4Mn0.9Li0.1O2·0.33H2O not only delivered a higher capacity retention of 84.04 % compared to the value of 28.09 % for K0.4MnO2·0.33H2O, but also maintained a greatly enhanced rate capability. This study provides a new opportunity for designing layered manganese-based cathode materials with high performance for PIBs.

Metagenomic next-generation sequencing for rapid detection of pulmonary infection in patients with acquired immunodeficiency syndrome.

BACKGROUND: Acquired immunodeficiency syndrome (AIDS) is associated with a high rate of pulmonary infections (bacteria, fungi, and viruses). To overcome the low sensitivity and long turnaround time of traditional laboratory-based diagnostic strategies, we adopted metagenomic next-generation sequencing (mNGS) technology to identify and classify pathogens. RESULTS: This study enrolled 75 patients with AIDS and suspected pulmonary infections who were admitted to Nanning Fourth People's Hospital. Specimens were collected for traditional microbiological testing and mNGS-based diagnosis. The diagnostic yields of the two methods were compared to evaluate the diagnostic value (detection rate and turn around time) of mNGS for infections with unknown causative agent. Accordingly, 22 cases (29.3%) had a positive culture and 70 (93.3%) had positive valve mNGS results (P value < 0.0001, Chi-square test). Meanwhile, 15 patients with AIDS showed concordant results between the culture and mNGS, whereas only one 1 patient showed concordant results between Giemsa-stained smear screening and mNGS. In addition, mNGS identified multiple microbial infections (at least three pathogens) in almost 60.0% of patients with AIDS. More importantly, mNGS was able to detect a large variety of pathogens from patient tissue displaying potential infection and colonization, while culture results remained negative. There were 18 members of pathogens which were consistently detected in patients with and without AIDS. CONCLUSIONS: In conclusion, mNGS analysis provides fast and precise pathogen detection and identification, contributing substantially to the accurate diagnosis, real-time monitoring, and treatment appropriateness of pulmonary infection in patients with AIDS.

Fluorinated saccharide-derived hard carbon as a cathode material of lithium primary batteries: effect of the polymerization degree of the starting saccharide.

Fluorinated hard carbon materials have been considered to be a good candidate of cathode materials of Li/CFx batteries. However, the effect of the precursor structure of the hard carbon on the structure and electrochemical performance of fluorinated carbon cathode materials has yet to be fully studied. In this paper, a series of fluorinated hard carbon (FHC) materials are prepared by gas phase fluorination using saccharides with different degrees of polymerization as a carbon source, and their structure and electrochemical properties are studied. The experimental results show that the specific surface area, pore structure, and defect degree of hard carbon (HC) are enhanced as the polymerization degree (i.e. molecular weight) of the starting saccharide increases. At the same time, the F/C ratio increases after fluorination at the same temperature, and the contents of electrochemically inactive -CF2 and -CF3 groups also become higher. At the fluorination temperature of 500 °C, the obtained fluorinated glucose pyrolytic carbon shows good electrochemical properties, with a specific capacity of 876 mA h g-1, an energy density of 1872 W kg-1, and a power density of 3740 W kg-1. This study provides valuable insights and references for selecting suitable hard carbon precursors to develop high-performance fluorinated carbon cathode materials.

Reaching the initial coulombic efficiency and structural stability limit of P2/O3 biphasic layered cathode for sodium-ion batteries.

The P2/O3 biphasic layered oxide (NaxMn1-yMyO2, M: doping elements) is a cathode family with great promise for sodium-ion batteries (SIBs) because of their tunable electrochemical performance and low cost. However, the ultrahigh initial coulombic efficiency (ICE) and inferior cycling performance of P2/O3-NaxMn1-yMyO2 need to be improved for practical application. Herein, Ni/Cu co-doped P2/O3-Na0.75Mn1-yNiy-zCuzO2 materials are well-designed. The ultrahigh ICE can be restrained by altering the ratio of P2/O3 via adjusting Ni content, and the structural stability can be improved by Cu doping via enlarging parameter c of O3 phase and suppressing irreversible P2-O2 phase transformation. The optimal P2/O3-Na0.75Mn0.6Ni0.3Cu0.1O2 delivers a capacity of 142.4 with ICE of 107.8%, superior capacity retention in the temperature range of -40 âˆ¼ 30 °C, and rate performance of 95.9 mAh g-1 at 1.2 A g-1. The overall storage mechanism of P2/O3-Na0.75Mn0.6Ni0.3Cu0.1O2 is revealed by the combination of electrochemical profiles, in situ X-ray diffraction, and first-principles calculations. The Na-ion full battery based on P2/O3-Na0.75Mn0.6Ni0.3Cu0.1O2 cathode can achieve a remarkable energy density of 306.9 Wh kg-1 with a power density of 695.5 W kg-1 at 200 mA g-1. This work may shed light on the rational design of high-performance P2/O3 biphasic layered cathode for SIBs.

Accelerable Self-Sintering of Solvent-Free Molybdenum/Wax Biodegradable Composites for Multimodally Transient Electronics.

Biodegradable conductive composites are key materials or components for printable transient electronics that can be fabricated in a low-cost and high-efficiency manner, thereby boosting their wide applications in biomedical engineering, hardware security, and environmental-friendly electronics. Continuous efforts in this area still lie in the development of strategies for highly conductive, safe, and reliable biodegradable conductive composite materials and devices. This paper introduces molybdenum/wax composites for multimodally printable transient electronics in which multiple transience modes including dissolution-induced degradation and thermally triggered degradation are available. Systematic experiments demonstrate several advantages and unique properties of this material system, including solvent-free fabrication, self-sintering behavior, and long-term and high conductivity via accelerable self-sintering treatment and rehealing capabilities. Notably, the immersion of molybdenum/wax composites in phosphate buffer solution can provide both positive effects (accelerated self-sintering-dominated) and negative effects (degradation-dominated) on their electrical conductivities. Mechanism analyses reveal the basis for balancing the degradation and accelerated self-sintering processes. The presented demonstrations foreshadow opportunities of the developed molybdenum/wax composites in rehealable electronics, on-demand smart transient electronics with multiple transience modes, and many other related unusual applications.

Enhanced Energy Density for P-Doped Hierarchically Porous Carbon-Based Symmetric Supercapacitor with High Operation Potential in Aqueous H2SO4 Electrolyte.

Phosphorus-doped hierarchically porous carbon (HPC) is prepared with the assistance of freeze-drying using colloid silica and phytic acid dipotassium salt as a hard template and phosphorus source, respectively. Intensive material characterizations show that the freeze-drying process can effectively promote the porosity of HPC. The specific surface area and P content for HPC can reach up to 892 m2 g-1 and 2.78 at%, respectively. Electrochemical measurements in aqueous KOH and H2SO4 electrolytes reveal that K+ of a smaller size can more easily penetrate the inner pores compared with SO42-, while the developed microporosity in HPC is conducive to the penetration of SO42-. Moreover, P-doping leads to a high operation potential of 1.5 V for an HPC-based symmetric supercapacitor, resulting in an enhanced energy density of 16.4 Wh kg-1. Our work provides a feasible strategy to prepare P-doped HPC with a low dosage of phosphorus source and a guide to construct a pore structure suitable for aqueous H2SO4 electrolyte.

Nickel-Embedded Carbon Materials Derived from Wheat Flour for Li-Ion Storage.

The biomass-based carbons anode materials have drawn significant attention because of admirable electrochemical performance on account of their nontoxicity and abundance resources. Herein, a novel type of nickel-embedded carbon material (nickel@carbon) is prepared by carbonizing the dough which is synthesized by mixing wheat flour and nickel nitrate as anode material in lithium-ion batteries. In the course of the carbonization process, the wheat flour is employed as a carbon precursor, while the nickel nitrate is introduced as both a graphitization catalyst and a pore-forming agent. The in situ formed Ni nanoparticles play a crucial role in catalyzing graphitization and regulating the carbon nanocrystalline structure. Mainly owing to the graphite-like carbon microcrystalline structure and the microporosity structure, the NC-600 sample exhibits a favorable reversible capacity (700.8 mAh g-1 at 0.1 A g-1 after 200 cycles), good rate performance (51.3 mAh g-1 at 20 A g-1), and long-cycling durability (257.25 mAh g-1 at 1 A g-1 after 800 cycles). Hence, this work proposes a promising inexpensive and highly sustainable biomass-based carbon anode material with superior electrochemical properties in LIBs.

Monitoring mitochondrial pH with a hemicyanine-based ratiometric fluorescent probe.

Mitochondria as essential organelles play critical roles in cellular metabolism. Mitochondrial pH is a vital parameter that directly affects the unique function of mitochondria. Herein, we present a new ratiometric fluorescent probe M-pH for monitoring the pH within the mitochondria. M-pH consists of a stable and large π-electron conjugated merocyanine system. The lipophilic cationic benzyl group will facilitate the accumulation of M-pH in mitochondria. The phenol unit is the recognition moiety, achieving the ratiometric sensing of pH changes. The experimental results indicate that M-pH displays ratiometric fluorescence response to different pH values. Meanwhile, M-pH shows negligible response to common species, and has high stability and low cytotoxicity. In biological experiments, M-pH can solely accumulate in mitochondria and visualize the pH changes during mitophagy and cell apoptosis. We thus believe that M-pH has great potential as a practical tool for real-time monitoring of pH changes of mitochondria, contributing to revealing the pathogenesis of mitochondrial pH associated diseases.

Folding Large Graphene-on-Polymer Films Yields Laminated Composites with Enhanced Mechanical Performance.

A folding technique is reported to incorporate large-area monolayer graphene films in polymer composites for mechanical reinforcement. Compared with the classic stacking method, the folding strategy results in further stiffening, strengthening, and toughening of the composite. By using a water-air-interface-facilitated procedure, an A5-size 400 nm thin polycarbonate (PC) film is folded in half 10 times to a ≈0.4 mm thick material (1024 layers). A large PC/graphene film is also folded by the same process, resulting in a composite with graphene distributed uniformly. A three-point bending test is performed to study the mechanical performance of the composites. With a low volume fraction of graphene (0.085%), the Young's modulus, strength, and toughness modulus are enhanced in the folded composite by an average of 73.5%, 73.2%, and 59.1%, respectively, versus the pristine stacked polymer films, or 40.2%, 38.5%, and 37.3% versus the folded polymer film, proving a remarkable mechanical reinforcement from the combined folding and reinforcement of graphene. These results are rationalized with combined theoretical and computational analyses, which also allow the synergistic behavior between the reinforcement and folding to be quantified. The folding approach could be extended/applied to other 2D nanomaterials to design and make macroscale laminated composites with enhanced mechanical properties.

A Water-Area Recognition Approach Based on "Tuned" Texture Mask and Cuckoo Search Algorithm.

Texture feature extraction is a key topic in many applications of image analysis; a lot of techniques have been proposed to measure the characteristics of this field. Among them, texture energy extracted with a mask is a rotation and scale invariant texture descriptor. However, the tuning process is computationally intensive and easily trap into the local optimum. In the proposed approach, a "Tuned" mask is utilized to extract water and nonwater texture; the optimal "Tuned" mask is acquired by maximizing the texture energy value via a newly proposed cuckoo search (CS) algorithm. Experimental results on samples and images show that the proposed method is suitable for texture feature extraction, the recognition accuracy is higher than the genetic algorithm (GA), particle swarm optimization (PSO) and the gravitational search algorithm (GSA) optimized "Tuned" mask scheme, and the water area could be well recognized from the original image. Experimental results show that the proposed method could exhibit better performance than other methods involved in the paper in terms of optimization ability and recognition result.

Porous Two-Dimensional Monolayer Metal-Organic Framework Material and Its Use for the Size-Selective Separation of Nanoparticles.

Rational bottom-up construction of two-dimensional (2D) covalent or noncovalent organic materials with precise structural control at the atomic or molecular level remains a challenge. The design and synthesis of metal-organic frameworks (MOFs) based on new building blocks is of great significance in achieving new types of 2D monolayer MOF films. Here, we demonstrate that a complexation between copper(II) ions and tri(ß-diketone) ligands yields a novel 2D MOF structure, either in the form of a powder or as a monolayer film. It has been characterized by Fourier transform infrared, Raman, ultraviolet-visible, X-ray photoelectron, and electron paramagnetic resonance spectroscopies. Selected area electron diffraction and powder X-ray diffraction results show that the MOF is crystalline and has a hexagonal structure. A MOF-based membrane has been prepared by vacuum filtration of an aqueous dispersion of the MOF powder onto a porous Anodisc filter having pore size 0.02 µm. The porous MOF membrane filters gold nanoparticles with a cutoff of ∼2.4 nm.

Controlling the Thickness of Thermally Expanded Films of Graphene Oxide.

"Paper-like" film material made from stacked and overlapping graphene oxide sheets can be exfoliated (expanded) through rapid heating, and this has until now been done with no control of the final geometry of the expanded graphene oxide material, i.e., the expansion has been physically unconstrained. (As a consequence of the heating and exfoliation, the graphene oxide is "reduced", i.e., the graphene oxide platelets are deoxygenated to a degree.) We have used a confined space to constrain the expanding films to a controllable and uniform thickness. By changing the gap above the film, the final thickness of expanded films prepared from, e.g., a 10 µm-thick graphene oxide film, could be controlled to values such as 20, 30, 50, or 100 µm. When the expansion of the films was unconstrained, the final film was broken into pieces or had many cracks. In contrast, when the expansion was constrained, it never cracked or broke. Hot pressing the expanded reduced graphene oxide films at 1000 °C yielded a highly compact structure and promoted graphitization. Such thickness-controlled expansion of graphene oxide films up to tens or hundreds of times the original film thickness was used to emboss patterns on the films to produce areas with different thicknesses that remain connected "in plane". In another set of experiments, we treated the original graphene oxide film with NaOH before its controlled expansion resulted in a different structure featuring uniformly distributed pores and interconnected layers as well as simultaneous activation of the carbon.

The influence of house dust mite sublingual immunotherapy on the TSLP-OX40L signaling pathway in patients with allergic rhinitis.

BACKGROUND: This study aimed to investigate the clinical efficacy of sublingual immunotherapy (SLIT) with house dust mite (HDM) extract and to examine T helper 2 (Th2)-type immune responses mediated by the thymic stromal lymphopoietin (TSLP-OX40L) signaling pathway in patients with moderate to severe allergic rhinitis (AR) after 12-month HDM SLIT. METHODS: Forty-six cases of HDM-sensitized patients with persistent AR in southern China were enrolled in this study. Clinical efficacy of SLIT was assessed by determining the individual nasal symptom score (INSS) and total nasal symptom score (TNSS) after 12-month HDM SLIT. Moreover, the TSLP-OX40L signaling pathway was investigated through measurements of TSLP by enzyme-labeled immunosorbent assay (ELISA) and OX40L by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and flow cytometry. RESULTS: After 12 months of HDM SLIT, TNSS and INSS were significantly decreased overall compared with baseline values (p < 0.001). By the end of the 12-month HDM SLIT, TNSS had declined by ∼50% compared with baseline, and the corresponding level of TSLP in nasal lavage decreased significantly (p < 0.05). The level of OX40L messenger RNA (mRNA) in blood was markedly decreased significantly after 12-month HDM SLIT compared with baseline (t = 12.300, p < 0.05). Furthermore, significant decreases in OX40L expression on the surface of peripheral blood mononuclear cells (PBMCs) (t = 13.100, p < 0.05) and OX40L expression on the surface of CD11c+CD86+ cells in PBMCs (t = 9.946, p < 0.05) after 12-month HDM SLIT were observed. CONCLUSION: HDM SLIT downregulated Th2-type immune responses mediated by the TSLP-OX40L signaling pathway in patients with persistent moderate to severe AR.

The CO2 Storage Capacity of the Intercalated Diaminoalkane Graphene Oxides: A Combination of Experimental and Simulation Studies.

To study the effect of interlayer spacing of pillared graphene oxides (GOs) on CO2 uptake, we have obtained CO2 isotherms with respect to the interlayer distance of pillared graphene oxide by both experimental and simulation methods. Interlayer distances of GO were modulated by intercalation of three kinds of diaminoalkanes with a different number of carbon atoms (NH2(CH2) n NH2, n = 4, 8, and 12) as pillars. The intercalated GOs (IGOs) and their reduced products (RIGOs) are characterized using a variety of approaches such as X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and N2 adsorption. Gas adsorption performance shows that the CO2 uptake of IGOs and RIGOs decrease with the increase of the interlayer distance at low pressure, while at high pressure, the adsorption capacity of IGO-12 has a larger growth than those of both IGO-4 and IGO-8 and surpasses them at 30 bar. The contribution of the electrostatics to CO2 adsorption is larger than that of van der Waals force at low pressures, whereas for the high pressures, the adsorption is dominated by van der Waals force.

Reduced graphene oxide aerogel with high-rate supercapacitive performance in aqueous electrolytes.

Reduced graphene oxide aerogel (RGOA) is synthesized successfully through a simultaneous self-assembly and reduction process using hypophosphorous acid and I2 as reductant. Nitrogen sorption analysis shows that the Brunauer-Emmett-Teller surface area of RGOA could reach as high as 830 m2 g-1, which is the largest value ever reported for graphene-based aerogels obtained through the simultaneous self-assembly and reduction strategy. The as-prepared RGOA is characterized by a variety of means such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrochemical tests show that RGOA exhibits a high-rate supercapacitive performance in aqueous electrolytes. The specific capacitance of RGOA is calculated to be 211.8 and 278.6 F g-1 in KOH and H2SO4 electrolytes, respectively. The perfect supercapacitive performance of RGOA is ascribed to its three-dimensional structure and the existence of oxygen-containing groups.

Flow-injection chemiluminescence method for the determination of naphazoline hydrochloride and oxymetazoline hydrochloride.

A sensitive and simple flow-injection chemiluminescence (FI-CL) method, which was based on the CL intensity generated from the redoxreaction of potassium permanganate (KMnO4)-formaldehyde in vitriol (H2SO4) medium, has been developed, validated and applied for the determination of naphazoline hydrochloride and oxymetazoline hydrochloride. Besides oxidants and sensitizers, the effect of the concentration of H(2)SO(4), KMnO4 and formaldehyde was investigated. Under the optimum conditions, the linear range was 1.0 x 10(-2)-7.0 mg/L for naphazoline hydrochloride and 5.0 x 10(-2)-10.0 mg/L for oxymetazoline hydrochloride. During seven repeated inter-day and intra-day precision tests of 0.1, 1.0 and 10.0 mg/L samples, the relative standard deviations all corresponded to reference values. The detection limit was 8.69 x 10(-3) mg/L for naphazoline hydrochloride and 3.47 x 10(-2) mg/L for oxymetazoline hydrochloride (signal-to-noise ratio < or = 3). This method has been successfully implemented for the determination of naphazoline hydrochloride and oxymetazoline hydrochloride in pharmaceuticals.

[Evaluation of tympanoplasty with reconstruction of the external canal after mastoidectomy for cholesteatoma].

OBJECTIVE: To investigate the method to repair the deletion of external canal and opened mastoid space after mastoidectomy. METHOD: One stage tympanoplasty with reconstruction of the external canal with temporal cortex was completed in 58 cases (58 ears) with cholesteatoma. RESULT: During the follow-up ranging from one to three years, there was only one relapse. The configuration of external canal was almost normal and pneumatic mastoid space was maintained. Hearing was improved over 30dB in five ears, 20 to 29 dB in 11 ears, 10 to 19 dB in 30 ears, less 10 dB in eight ears and hearing wasn't improved in four ears. CONCLUSION: One stage tympanoplasty with reconstruction of the external canal after mastoidectomy for cholesteatoma is a practical way to improve hearing and decrease recurrence.

[Evaluation on hemorrhage factors secondary to endoscopic sinus surgery with multiple stepwise regression analysis].

OBJECTIVE: To investigate the factors relating to bleeding secondary to endoscopic sinus surgery. METHOD: 193 patients suffered from nasal polyps, chronic sinusitis and underwent endoscopic sinus surgery between May 1995 and February 2001 were analyzed. These patients's state of operation affairs tallies with this study's selecting condition and their clinic data was complete. The factors relating to bleeding secondary to endoscopic sinus surgery were analyzed with multiple stepwise regression analysis with STATA31 statistic computer software. RESULT: 20 selected hemorrhage factors were analyzed with multiple stepwise regressions. With these factors progressively removed, 5 items as follows showed relation to the hemorrhage: X18, X19, X9, X11, X20. An optimal regression equation for predicting hemorrhage has been established. According to this equation, the blood loss of endoscopic sinus surgery could be estimated. CONCLUSION: The clinical signification of 5 factors were recognized: 1. X18: Anatomy mark was broken down in former operation and showed difficulty when identified. 2. X19: Sinus presented proliferation such as scar forming, blood vessel showed hyperemia, sinus wall showed hyperplasia, Aperture being narrow and small. 3. X9: Sinusitis showed late stages. 4. X11: Estimated blood loss was significantly greater under general anesthesia. 5. X20: Operation went on over 2 hours. If aforementioned condition appears, blood loss may exceed 200 ml.