A Novel Low-Density-Biomass-Carbon Composite Coated with Carpet-like and Dandelion-Shaped Rare-Earth-Doped Cobalt Ferrite for Enhanced Microwave Absorption.

A novel low-density composite for the absorption of microwaves was prepared by loading La-doped spinel cobalt ferrite (La-CFO) onto biomass carbon (BC) derived from corn stalks using a hydrothermal method. This composite (La-CFO@BC) not only maintained the advantageous properties of low density and abundant porosity, but also exhibited a unique morphology, with La-CFO displaying a carpet-like structure interspersed with dandelion-shaped particles. The incorporation of La-CFO effectively tuned the electromagnetic parameters of the composite, thereby improving its impedance-matching attributes and its ability to absorb microwave radiation. At a frequency of 12.8 GHz for electromagnetic waves and with a thickness of 2.5 mm, La-CFO@BC demonstrated remarkable performance in microwave absorption, attaining a noteworthy minimum reflection (RLmin) of -53.2 dB and an effective absorption bandwidth (EAB) of 6.4 GHz. Furthermore, by varying the thickness of the La-CFO@BC within the range of 1.0 to 5.5 mm, the EAB could be broadened to 13.8 GHz, covering the entire X-band, the entire Ku-band, and a substantial portion of the C-band. This study demonstrated that La-CFO@BC was a promising alternative for electromagnetic wave attenuation, which offered superior performance in microwave absorption.

Assessment of left atrial function in patients with metabolic syndrome by four-dimensional automatic left atrial quantification.

OBJECTIVE: This study aimed at assessing the changes of left atrial (LA) volume and strain function in metabolic syndrome (MS) patients using four-dimensional automatic left atrial quantification (4D-LAQ) and exploring independent correlative factors for LA function. METHODS: A total of 110 MS patients and 70 normal controls were selected and assigned into the MS group and the control group, respectively. Echocardiogram parameters were routinely examined and the thickness of epicardial adipose tissue (EAT) were measured with a parasternal long axis of left ventricle(LV). The LA volume and strain parameters were determined using 4D-LAQ. The independent correlation factors for LA strain parameters in MS patients were investigated through linear regression analysis. RESULTS: Compared with the control group, LA volume parameters were increased in the MS group, LA strain parameters and LA emptying fraction (LAEF) were decreased (all P < 0.05). EAT thickness is associated with LA reservoir longitudinal strain (LASr), conduit longitudinal strain (LAScd), reservoir circumferential strain (LASr-c), and conduit circumferential strain (LAScd-c) (all P < 0.05). LA contraction longitudinal (LASct) and circumferential strain (LASct-c) were not statistically significant. Regression analysis results show that systolic blood pressure (SBP) and triglyceride (TG) are independent correlative factors. Intra-observer and inter-observer repeatability test showed that the LA parameters examined by 4D-LAQ had good agreement. CONCLUSIONS: 4D-LAQ is capable of effectively assessing the LA function in MS patients and providing a useful reference for clinical diagnosis. SBP and TG serve as the independent correlative factors for LA function.

Association between epicardial adipose tissue and myocardial work by non-invasive left ventricular pressure-strain loop in people with suspected metabolic syndrome.

Given the inconsistent results on the prognostic significance of epicardial adipose tissue (EAT), the purpose of the present study was to investigate the association of EAT thickness and myocardial work by non-invasive left ventricular pressure-strain loop in people with suspected metabolic syndrome (MS). A total of 194 participants imaged with echocardiography were evaluated. In accordance with the median EAT thickness, MS patients fell into thin EAT group and thick EAT group. Conventional echocardiographic parameters, global longitudinal strain (GLS) and the global myocardial work parameters obtained by pressure-strain loop analysis, comprising the global work index (GWI), global work efficiency (GWE), global constructive work (GCW) and global wasted work (GWW) were compared between the two groups. In comparison with the thin EAT group, thick EAT group achieved significantly higher values in interventricular septal thickness, end-diastolic left ventricular posterior wall thickness, left ventricular mass index and GWW (p < 0.05). while the absolute value of GLS, GWI, GCW, and GWE were notably lower in the thick EAT group (p < 0.001). EAT thickness showed a significant correlation with GWI and GCW (r = - 0.328, p = 0.001; r = - 0.253, p = 0.012), and also independently correlated with GWI and GCW in the multivariate regression analysis (ß = - 0.310, p = 0.001; ß = - 0.199, p = 0.049). EAT thickness is associated with left ventricular myocardial function in subjects with suspected metabolic syndrome, independently of other risk factors. Further studies are supposed to ensure the causal associations and related mechanisms.

The Chemical Composition and Health-Promoting Benefits of Vegetable Oils-A Review.

With population and economic development increasing worldwide, the public is increasingly concerned with the health benefits and nutritional properties of vegetable oils (VOs). In this review, the chemical composition and health-promoting benefits of 39 kinds of VOs were selected and summarized using Web of Science TM as the main bibliographic databases. The characteristic chemical compositions were analyzed from fatty acid composition, tocols, phytosterols, squalene, carotenoids, phenolics, and phospholipids. Health benefits including antioxidant activity, prevention of cardiovascular disease (CVD), anti-inflammatory, anti-obesity, anti-cancer, diabetes treatment, and kidney and liver protection were examined according to the key components in representative VOs. Every type of vegetable oil has shown its own unique chemical composition with significant variation in each key component and thereby illustrated their own specific advantages and health effects. Therefore, different types of VOs can be selected to meet individual needs accordingly. For example, to prevent CVD, more unsaturated fatty acids and phytosterols should be supplied by consuming pomegranate seed oil, flaxseed oil, or rice bran oil, while coconut oil or perilla seed oil have higher contents of total phenolics and might be better choices for diabetics. Several oils such as olive oil, corn oil, cress oil, and rice bran oil were recommended for their abundant nutritional ingredients, but the intake of only one type of vegetable oil might have drawbacks. This review increases the comprehensive understanding of the correlation between health effects and the characteristic composition of VOs, and provides future trends towards their utilization for the general public's nutrition, balanced diet, and as a reference for disease prevention. Nevertheless, some VOs are in the early stages of research and lack enough reliable data and long-term or large consumption information of the effect on the human body, therefore further investigations will be needed for their health benefits.

Evaluation of global and regional myocardial work in hypertrophic cardiomyopathy patients by left ventricular pressure-strain loop.

OBJECTIVE: This study aimed to investigate the value of left ventricular (LV) press-strain loop (PSL) in evaluating global and regional myocardial work (MW) in hypertrophic cardiomyopathy (HCM) patients. METHODS: A total of 30 HCM patients with interventricular septum hypertrophy (HCM group) and 35 healthy subjects (control group) were selected from First Hospital of Qinhuangdao. The general clinical data and conventional ultrasound parameters of two groups were acquired. The MW parameters were analyzed using LV PSL. The regional MW parameters in the HCM group were compared between ventricular septum and the free walls of left ventricle. RESULTS: The epicardial adipose tissue thickness of the HCM group was significantly greater than that of the control group (P < 0.05). Global work efficiency was significantly reduced, while global wasted work was increased in patients with HCM compared with controls (all P < 0.05). The HCM group was compared in the group, to be specific, in the HCM group, the work index, the work efficiency, and the longitudinal strain on the interventricular septum were lower than those on the free wall (all P < 0.05). CONCLUSION: PSL is more effective than LVEF in assessing left ventricular systolic function in HCM and is able to quantify regional myocardial work in the ventricular septum in HCM patients with preserved LVEF, suggesting a novel idea for clinical diagnosis and assessment.

Improving the Cellulose Enzymatic Digestibility of Sugarcane Bagasse by Atmospheric Acetic Acid Pretreatment and Peracetic Acid Post-Treatment.

Pretreatment of sugarcane bagasse (SCB) by aqueous acetic acid (AA), with the addition of sulfuric acid (SA) as a catalyst under mild condition (<110 °C), was investigated. A response surface methodology (central composite design) was employed to study the effects of temperature, AA concentration, time, and SA concentration, as well as their interactive effects, on several response variables. Kinetic modeling was further investigated for AA pretreatment using both Saeman's model and the Potential Degree of Reaction (PDR) model. It was found that Saeman's model showed a great deviation from the experimental results, while the PDR model fitted the experimental data very well, with determination coefficients of 0.95-0.99. However, poor enzymatic digestibility of the AA-pretreated substrates was observed, mainly due to the relatively low degree of delignification and acetylation of cellulose. Post-treatment of the pretreated cellulosic solid well improved the cellulose digestibly by further selectively removing 50-60% of the residual linin and acetyl group. The enzymatic polysaccharide conversion increased from <30% for AA-pretreatment to about 70% for PAA post-treatment.

Synthesis and Computational Investigation of Antioxidants Prepared by Oxidative Depolymerization of Lignin and Aldol Condensation of Aromatic Aldehydes.

Novel antioxidants are synthesized by CuSO4 -catalyzed oxidative depolymerization of lignin to form aromatic aldehydes followed by aldol condensation with methyl ethyl ketone (MEK). Aldol condensation greatly improves the antioxidation ability of lignin depolymerized products. Three lignin monomeric aromatic aldehydes, - p-hydroxybenzaldehyde, vanillin, and syringaldehyde - are further employed for aldol condensation with MEK, resulting in successful synthesis of new antioxidants 1-(4-hydroxyphenyl)pent-1-en-3-one (HPPEO), 1-(4-hydroxy-3-methoxyphenyl)pent-1-en-3-one (HMPPEO), and 1-(4-hydroxy-3,5-dimethoxyphenyl)pent-1-en-3-one (HDMPPEO), respectively. Kinetic modeling illustrates that p-hydroxybenzaldehyde has the highest rate of reaction with MEK, followed by vanillin and then syringaldehyde, which is probably affected by the presence of methoxy groups. The syringaldehyde-derived product (HDMPPEO) displays the best antioxidation ability. As revealed by density functional theory calculations, electron-donating groups, such as methoxy, and conjugated side chains effectively improve the antioxidation ability. A hydrogen atom transfer (HAT) mechanism tends to occur in nonpolar solvents, whereas a sequential proton-loss electron transfer (SPLET) mechanism is favored in polar solvents. This work thus can inspire new pathways for valorization of lignin to produce high value-added products.

Topological spin texture in the pseudogap phase of a high-Tc superconductor.

An outstanding challenge in condensed-matter-physics research over the past three decades has been to understand the pseudogap (PG) phenomenon of the high-transition-temperature (high-Tc) copper oxides. A variety of experiments have indicated a symmetry-broken state below the characteristic temperature T* (refs. 1-8). Among them, although the optical study5 indicated the mesoscopic domains to be small, all these experiments lack nanometre-scale spatial resolution, and the microscopic order parameter has so far remained elusive. Here we report, to our knowledge, the first direct observation of topological spin texture in an underdoped cuprate, YBa2Cu3O6.5, in the PG state, using Lorentz transmission electron microscopy (LTEM). The spin texture features vortex-like magnetization density in the CuO2 sheets, with a relatively large length scale of about 100 nm. We identify the phase-diagram region in which the topological spin texture exists and demonstrate the ortho-II oxygen order and suitable sample thickness to be crucial for its observation by our technique. We also discuss an intriguing interplay observed among the topological spin texture, PG state, charge order and superconductivity.

Model-based process intensification of dilute acid pre-hydrolysis of oil palm empty fruit bunch biomass for pretreatment and furfural production.

A novel process for simultaneous production of furfural and pretreatment of oil palm empty fruit bunch (EFB) by dilute acid pre-hydrolysis was developed based on non-isothermal kinetic modeling. Mass transfer analysis suggested that the internal diffusion could be neglected as diffusion time of sulfuric acid in EFB particles was significantly shorter than the pre-hydrolysis period, whereas the heating stage could not be neglected due to a significant part of xylan was solubilized at the stage. A strategy for increasing furfural yield was developed by intermittent discharging of steam, resulting in 71.4 % furfural yield. The pretreated solids showed good enzymatic digestibility. 136.3 g/L glucose corresponding to 81.6 % yield was obtained by high-solid loading hydrolysis. 95.4 g furfural and 212 g glucose could be obtained from 1 kg dry EFB. Therefore, non-isothermal effects on polysaccharide hydrolysis and pentose decomposition should be considered carefully for an efficient process design of EFB biorefining.

Distribution of birds in the high-altitude area of Mount Everest.

The species and abundance of birds in the high altitude area of Mount Everest decreased sharply with the increase of altitude. Alpine Choughs forage at altitudes of up to 8000 m and are the highest distribution of birds.

Oxidative pretreatment of lignocellulosic biomass for enzymatic hydrolysis: Progress and challenges.

Deconstruction of cell wall structure is important for biorefining of lignocellulose to produce various biofuels and chemicals. Oxidative delignification is an effective way to increase the enzymatic digestibility of cellulose. In this work, the current research progress on conventional oxidative pretreatment including wet oxidation, alkaline hydrogen peroxide, organic peracids, Fenton oxidation, and ozone oxidation were reviewed. Some recently developed novel technologies for coupling pretreatment and direct biomass-to-electricity conversion with recyclable oxidants were also introduced. The primary mechanism of oxidative pretreatment to enhance cellulose digestibility is delignification, especially in alkaline medium, thus eliminating the physical blocking and non-productive adsorption of enzymes by lignin. However, the cost of oxidative delignification as a pretreatment is still too expensive to be applied at large scale at present. Efforts should be made particularly to reduce the cost of oxidants, or explore valuable products to obtain more revenue.

Current-Induced Magnetic Skyrmions with Controllable Polarities in the Helical Phase.

We report the current-induced creation of magnetic skyrmions in a chiral magnet FeGe nanostructure by using in situ Lorentz transmission electron microscopy. We show that magnetic skyrmions with controllable polarity can be transferred from the helical ground state simply by controlling the direction of the current flow at zero magnetic fields. The force analysis and symmetry consideration, backed up by micromagnetic simulations, well explain the experimental results, where magnetic skyrmions are created because of the edge instability of the helical state in the presence of spin-transfer torque. The on-demand generation of skyrmions and control of their polarity by electric current without the need for a magnetic field will enable novel purely electric-controlled skyrmion devices.

Light-driven lignocellulosic biomass conversion for production of energy and chemicals.

The depletion of fossil fuels and the increasingly severe environmental pollution caused by massive fossil fuel consumption has driven the quick development of emerging renewable energy technologies. As the most extensive renewable carbon resource, lignocellulose is the potential substitute of fossil resources because of its sustainability and carbon-neutral features. Efficient lignocellulose conversion based on photocatalysis is a promising topic because of sustainable solar energy and the mild condition. This review highlights state-of-the-art photocatalytic technologies for lignocellulosic biomass conversion, focusing on the electricity generation, hydrogen production, and high-value-added biomass derivatives production. Moreover, the progress, challenge, and perspectives of related photocatalytic technologies are specifically discussed. It is recommended that developing more robust and efficient photocatalysts suitable for the complex structure of lignocellulose is necessary to promote the oxidation the biomass. Design and development of novel photochemical reactors and photoelectrochemical cells are also important for demonstration of light-driven lignocellulose conversion at larger scale.

(±)-Hyperpyran A: Terpenoid-based bicyclic dihydropyran enantiomers with hypoglycemic activity from Hypericum perforatum (St. John's wort).

(±)-Hyperpyran A (1a/1b), a pair of new terpenoid-based bicyclic dihydropyran enantiomers, were isolated from the aerial parts of Hypericum perforatum (St. John's wort). Their structures and absolute configurations were elucidated by NMR spectroscopic analyses, ECD comparison, and X-ray crystal diffraction. Compounds 1a/1b possess hexahydrocyclopenta[c]pyran ring system and a plausible biosynthetic pathway was also proposed. In addition, compound 1a exhibited a moderate promotion of glucose uptake activity in hepatocytes.

Atomic Short-Range Order in a Cation-Deficient Perovskite Anode for Fast-Charging and Long-Life Lithium-Ion Batteries.

Perovskite-type oxides are widely used for energy conversion and storage, but their rate-inhibiting phase transition and large volume change hinder the applications of most perovskite-type oxides for high-rate electrochemical energy storage. Here, it is shown that a cation-deficient perovskite CeNb3 O9 (CNO) can store a sufficient amount of lithium at a high charge/discharge rate, even when the sizes of the synthesized particles are on the order of micrometers. At 60 C (15 A g-1 ), corresponding to a 1 min charge, the CNO anode delivers over 52.8% of its capacity. In addition, the CNO anode material exhibits 96.6% capacity retention after 2000 charge-discharge cycles at 50 C (12.5 A g-1 ), indicating exceptional long-term cycling stability at high rates. The excellent cycling performance is attributed to the formation of atomic short-range order, which significantly prevents local and long-range structural rearrangements, stabilizing the host structure and being responsible for the small volume evolution. Moreover, the extremely high rate capacity can be explained by the intrinsically large interstitial sites in multiple directions, intercalation pseudocapacitance, atomic short-range order, and cation-vacancy-enhanced 3D-conduction networks for lithium ions. These structural characteristics and mechanisms can be used to design advanced perovskite electrode materials for fast-charging and long-life lithium-ion batteries.

Response mechanisms of Saccharomyces cerevisiae to the stress factors present in lignocellulose hydrolysate and strategies for constructing robust strains.

Bioconversion of lignocellulosic biomass to biofuels such as bioethanol and high value-added products has attracted great interest in recent decades due to the carbon neutral nature of biomass feedstock. However, there are still many key technical difficulties for the industrial application of biomass bioconversion processes. One of the challenges associated with the microorganism Saccharomyces cerevisiae that is usually used for bioethanol production refers to the inhibition of the yeast by various stress factors. These inhibitive effects seriously restrict the growth and fermentation performance of the strains, resulting in reduced bioethanol production efficiency. Therefore, improving the stress response ability of the strains is of great significance for industrial production of bioethanol. In this article, the response mechanisms of S. cerevisiae to various hydrolysate-derived stress factors including organic acids, furan aldehydes, and phenolic compounds have been reviewed. Organic acids mainly stimulate cells to induce intracellular acidification, furan aldehydes mainly break the intracellular redox balance, and phenolic compounds have a greater effect on membrane homeostasis. These damages lead to inadequate intracellular energy supply and dysregulation of transcription and translation processes, and then activate a series of stress responses. The regulation mechanisms of S. cerevisiae in response to these stress factors are discussed with regard to the cell wall/membrane, energy, amino acids, transcriptional and translational, and redox regulation. The reported key target genes and transcription factors that contribute to the improvement of the strain performance are summarized. Furthermore, the genetic engineering strategies of constructing multilevel defense and eliminating stress effects are discussed in order to provide technical strategies for robust strain construction. It is recommended that robust S. cerevisiae can be constructed with the intervention of metabolic regulation based on the specific stress responses. Rational design with multilevel gene control and intensification of key enzymes can provide good strategies for construction of robust strains.

All-iron ions mediated electron transfer for biomass pretreatment coupling with direct generation of electricity from lignocellulose.

A coupled process of biomass pretreatment for increasing cellulose digestibility and direct conversion of biomass to electricity has been developed with ferric or ferricyanide ions as the anode electron carriers, and Fe(NO3)3 activated by HNO3 as the cathode electron carriers. Pretreated substrates are subjected to enzymatic hydrolysis for release of fermentable sugars, while the pretreatment liquor is employed as anolyte for electricity generation in a liquid flow fuel cell (LFFC). Pretreatment of sugarcane bagasse with 2 M FeCl3 in anode reactor removes âˆ¼ 100% hemicelluloses and obtains 76% enzymatic glucan conversion (EGC), while pretreatment with 0.1 M K3[Fe(CN)6] in 0.5 M KOH achieves 78% lignin removal, 95.8% EGC and 85.1% xylan conversion. From 1000 g bagasse, 171.3 g fermentable sugars is produced with co-generation of 101.4 W·h electricity based on FeCl3 pretreatment, while 519 g fermentable sugars and 28.9 W·h electricity are obtained based on K3[Fe(CN)6] pretreatment.

[Research progress of polycyclic polyprenylated acylphloroglucinols natural products].

Due to their fascinating chemical structures and extensive pharmacological activities, polycyclic polyprenylated acylphloroglucinols(PPAPs) have become one of the current research hotspots of natural products. In particular, some of the PPAPs not only have novel non-traditional skeleton types, but also contain more unknown possible activities, which are of great significance for the development of lead compounds. The structure, source, biosynthetic pathway and pharmacological activities of PPAPs with non-traditio-nal skeleton types isolated and identified in recent years are reviewed, in order to provide references for further research on such compounds.

Overexpressing CCW12 in Saccharomyces cerevisiae enables highly efficient ethanol production from lignocellulose hydrolysates.

A Saccharomyces cerevisiae strain CCW12OE was constructed by overexpressing CCW12 in a previously reported strain WXY70 harboring six xylose utilization genes. CCW12OE produced an optimal ethanol yield of 98.8% theoretical value within 48 h in a simulated corn stover hydrolysate. CCW12OEwas comprehensively evaluated for ethanol production in Miscanthus, maize and corncob hydrolysates, among which a 96.1% theoretical value was achieved within 12 h in corncob hydrolysates. Under normal growth conditions, CCW12OE did not display altered cell morphology; however, in the presence of acetate, CCW12OE maintained relatively intact cell structure and increased cell wall thickness by nearly 50%, while WXY70 had abnormal cell morphology and reduced cell wall thickness by nearly 50%. Besides, CCW12OE had higher fermentation capacity than that of WXY70 in undetoxified and detoxified hydrolysates with both aerobic and anaerobic conditions, demonstrating that CCW12 overexpression alone exhibits improved stress resistance and better fermentation performance.