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A facile one-step, calcination-free strategy involving metal–organic framework templates was developed for synthesis of MnO2 superstructure with superior lithium storage properties, offering considerable advantages over the conventional thermal method.

Developing earth-abundant electrocatalysts for efficient oxygen evolution reaction (OER) is of paramount significance for electrochemical water splitting. Herein, an efficient in situ etching-deposition growth strategy is employed to transform pristine two-dimensional (2D) Co-metal-organic frameworks into hollow Ni/Co double hydroxide arrays (denoted as Ni/Co-DH), which not only yields a larger surface area and exposes more active sites but also decreases the activation energy to the OER. With structural and compositional benefits, the Ni/Co-DH exhibits high performance with an overpotential of 229 mV at 10 mA cm

In both underwater and semi-aquatic environments, the gut microbiota is of particular physiological importance for amphibious animals, given that the gut tract is among those organs in direct communication with the external environment. In this study, we examined the effects of these contrasting environments on the dominant bacteria in the guts of the amphibious mudskipper Boleophthalmus pectinirostris. Compared with the guts of normal mudskippers, in which the dominant bacteria were identified as Vibrio and Faecalibacterium, we found that Acinetobacter, Shigella, and Bacillus predominated in their guts after exposure to the semi-aquatic environment, whereas Escherichia, Bacteroides, and Bacillus were more prevalent in the guts in the underwater environment. The total number of cultured gut bacteria decreased significantly in the semi-aquatic environment. In semi-aquatic mudskippers, we also detected reductions and increases in the length and width of gut villi, respectively, whereas the width of gut villi declined and the number of goblet cells increased significantly in mudskippers maintained underwater. The mRNA expression of multiple gut transporters for glucose, long-chain fatty acids, and amino acids was found to increase markedly in both underwater and semi-aquatic environments, with the expression of most transporters being significantly higher in those mudskippers exposed to an underwater environment. Furthermore, we detected significant increases in the mRNA expression of pro-inflammatory cytokine transcripts in the guts of both underwater and semi-aquatic mudskippers on days 2, 4, and 6 of exposure, whereas the expression of IL-10 and TGFβ mRNA was more pronounced on days 4 and 8, respectively. Comparatively, we found that expression levels of cytokines in the guts of underwater mudskipper were substantially higher than those in the guts of semi-aquatic mudskippers. Collectively, our findings revealed notable differences in the gut microbiota and energy metabolism requirements of mudskippers exposed to underwater and semi-aquatic conditions, thereby providing a theoretical basis explaining the maintenance of a homeostatic state in mudskippers that constantly transition between these contrasting amphibious habitats.

Tetrodotoxin (TTX) is a kind of neurotoxin with great scientific research and medicinal value. Studies have confirmed that microorganism is one of the important sources of TTX. However, the specific biosynthetic and regulatory pathway of TTX production by microorganisms are still unclear. In this paper, out of twelve symbiotic bacteria screened from the wild puffer fish (Fugu rubripes) collected from coastal sea area of Ningbo (Zhejiang, China), a strain named He-1 isolated from the liver of puffer fish was found can produce TTX. It was identified as Bacillus cereus based on physiological, biochemical characteristics and 16S rDNA gene analysis. However, the strain He-2, which is the subculture strain of He-1, cannot produce TTX under the normal culture condition. Further study showed that by adding the metabolite of the He-1, the ability of TTX producing of He-2 could be restored. A peptide compound was obtained by separating and purifying of the metabolites from strain He-1, which could induce the TTX production of strain He-2. This work will provide a new way for further revealing the anabolic pathway of TTX.

Rendezvous in the blind fashion is known as one of the most robust and effective ways for cognitive users (CUs) to exchange control information under the dynamic interference of primary users (PUs). Earlier, no existing scheme could guarantee CUs to rendezvous blindly in each timeslot, which makes them experience relatively long exchange delay. Based on the mathematical concept of relaxed cyclic difference set ( DS ), this paper proposes two novel channel hopping (CH) schemes for multi-radio CUs with and without a synchronized time clock to rendezvous blindly in every timeslot. This achievement of minimum rendezvous delay is especially useful for such delay-sensitive applications as real-time voice and emergency communications. Moreover, based on a special class of DS, the proposed two schemes can closely approach the theoretical lower bound on the number of radio transceivers for CUs to rendezvous blindly in every timeslot and, hence, minimizes their required hardware complexity to exchange control information at the minimum rendezvous delay. Numerical simulation shows that, under dynamic PU interference, the proposed schemes outperform the existing ones in terms of the average throughput and delay of CUs.

Rapeseed oil has a similar oleic acid/linoleic acid ratio to human milk fat (HMF). However, it can hardly be used for human milk fat substitute (HMFS) synthesis due to high erucic acid content. In this study, Candida cylindracea lipase (CCL) was found to strongly discriminate against erucic acid. Free fatty acids containing low erucic acid and high oleic acid and linoleic acid were prepared from rapeseed oil hydrolysis catalyzed by CCL. The erucic acid content was only 1.58% (initial 8.70%), when the degree of hydrolysis reached 79.58%. The free fatty acids were used as acyl-donors in the acidolysis catalyzed by Novozym 40086. Considering acyl incorporation and migration, the optimum conditions were 1:8 (tripalmitin to acyl-donors), 40 °C and 2 h. The erucic acid content dropped to 0.97% in the HMFS. According to the Q-TOF-MS analysis, the HMFS was rich in 1,3-dioleoyl-2-palmitoyl-glycerol (18.20%) and 1-oleoyl-2-palmitoyl-3-linoleoyl-glycerol (17.96%), which was similar to HMF.

A feasible tuning method for oxygen vacancies was realized by annealing under 3 atm H

In order to explore the effect of slurry ice on myofibrillar protein of Pseudosciaena crocea, the changes in myofibrillar protein and muscle microstructure during storage were studied with crushed ice as a control. During the storage period, the rate of decrease in myofibrillar protein content, Ca2+‐ATPase activity, and total sulfhydryl groups in the slurry ice group was lower than in the control group (p, Slurry ice can delay the denaturation and degradation of fish myofibrillar protein. Slurry ice (−1℃) is the best one to keep protein of Pseudosciaena crocea. There was a linear correlation between the hydrophobicity and the storage time.

In the overlapped shell space between two adjacent cavitation bubbles, there theoretically exists a Zero-sum space without vibration due to the cavitation effect but still with pressure, high temperature and a high concentration of substances. Within the Zero-sum space, a stable environment for a chemical reaction is achievable under the ultrasound. In this work, some ring-shaped regions (outer diameter 48.90±3.5 μm, inner diameter 40.94±3.5 μm) on copper foil with distinctive morphology were investigated in the area covered by visible bubbles under ultrasound treatment in 1M NaOH for 3 h. The morphology and composition of these regions were found to be similar to that of sample fabricated in the same environment without ultrasound. It has confirmed the long-term existence of Zero-sum space and raised a hypothesis of Zero-sum space maintenance. This work may lead to release the ultrasonic synthesis from the limitation of ultrasonic frequency.

Cold chain logistics is a common way of fresh-keeping transportation at present, but in the actual transportation and storage process, temperature control is often not accurate, which leads to shortened shelf life. We evaluated the changes in the quality of yellow croaker (Pseudosciaena crocea) at different temperatures during transportation. Specimens of P. crocea were immersed in slurry ice for 20 min and stored at 22, 4, or -1°C for 4 days. During this period, the development of rancidity of P. crocea was measured by sensory (odor, skin, color, and flesh appearance) and biochemical (total number of colonies, total volatile basic nitrogen, and K value) analyses. A combination of sensory and biochemical parameters and the Arrhenius equation were used to predict the shelf life of P. crocea during storage. After verification under different storage temperatures, the relative error between the predicted and the measured values was found to be within 15%. The present work provides theoretical guidance for the quality control of P. crocea during transportation and storage. HIGHLIGHTS

With the increasing demand of electrochemical energy storage, Titanium niobium oxide (TiNb2O7), as an intercalation-type anode, is considered to be one of the most prominent materials due to high voltage (~1.6 V vs. Li+/Li), large capacity with rich redox couples (Ti4+/Ti3+, Nb4+/Nb3+, Nb5+/Nb4+) and good structure stability. In this review, we summarize the crystal structure, synthesis methods, applications of TiNb2O7 as electrodes for energy storage devices (e.g., rechargeable batteries, hybrid supercapacitors, and hydrogen storage). In addition, the effects of modification strategies (micro/nano-architectures control, doping, carbon coating/compositing) on the Li-ion storage capability of TiNb2O7 are discussed. The development trend and challenges of TiNb2O7 electrodes for energy storage are highlighted. This review can provide direction for the future research of energy storage materials, and stimulate more unique discoveries of the intercalation-type materials.

FeSe2@reduced graphene oxide (rGO) composite was prepared by a facile one-step hydrothermal technique with FeSe2 nanoparticles uniformly achored on rGO nanosheets. The nano-sized FeSe2 particles effectively reduce the transfer length of Li ion and increase the sufficient contact area between the electrolyte and active material. Moreover, rGO can not only improve the electrical conductivity, but also prevent the agglomeration of nano-sized FeSe2, as well as accommodate the volume expansion and strain generated from the charge/discharge process. As an anode material applied in Li-ion storage, FeSe2/rGO composite delivers superior specific capacity of 1167.6 mAh/g, good cycling stability (908.2 mAh g−1 after 120 cycles at the current density of 500 mA g−1) and high-power characteristics (728.0 mAh g−1 at 1000 mA g−1), due to coexistent Li-ion storage mechanisms of surface capacitive behavior and diffusion-controlled process.

To improve the efficiency of blind rendezvous among multi-radio asynchronous cognitive users (CUs), this paper proposes to construct a common set of CH sequences at different computational complexity for guiding the multiple radios of each CU to perform channel hopping (CH). The main advantages of this construction include its approaching to the theoretical lower bound on the time-to-rendezvous of multi-radio asynchronous CH systems closely when any two CUs have only one commonly available channel due to the interference from primary users (PUs) and its effective reduction of the same metric when no PU interference exists. Numerical simulation also shows that, compared with the existing multi-radio asynchronous CH systems, the proposed CH sequences incur a shorter rendezvous delay under different numbers of radios or rendezvous channels.

Tantalum nitride (Ta

Fasting alters the structure of the intestine and its bacterial diversity, affecting the metabolism of three nutrients (sugar, fat, and protein). However, very little information is available on the effects of fasting on fish intestinal structure, bacterial flora, nutrient metabolism, and inflammation. In this study, fasting modified the intestinal bacterial floral compositions and diversity in mudskippers (Boleophthalmus pectinirostris), and altered the dominant flora in both semiaquatic (SA) and underwater (UW) conditions. The length of the intestinal villi and the thickness of the intestinal mucosa/submucosa decreased significantly during fasting. The intestinal mucosa/submucosa thickness of the SA group was obviously thinner than that in the UW group. The constitutive expression of glucose, long-chain fatty acid, and amino acid transporter mRNA was detected by real-time quantitative PCR. Expression was dramatically increased in the intestine after fasting. Interestingly, the expression of most of the transporters mRNA associated with energy metabolism was higher in the SA group than that in the UW group. Fasting also induced a pro-inflammatory response in the early and middle stages and an anti-inflammatory response in the middle and late stages. The fish intestine is more likely to present pro-inflammatory symptoms in SA and anti-inflammatory symptoms in UW. The results demonstrated that fasting plays a crucial role in the modulation of structure and function in the intestine and bacterial flora. The function of the fish intestine recovers more quickly after fasting in SA than that in UW.

Recent studies have shown that activation of liver X receptors (LXRs) attenuates the development of atherosclerosis, not only by regulating lipid metabolism but also by suppressing inflammatory signaling. Sphingosine 1-phosphate receptor 2 (S1PR2), an important inflammatory gene product, plays a role in the development of various inflammatory diseases. It was proposed that S1PR2 might be regulated by LXR-α. In the present study, the effect of LXR-α on tumor necrosis factor-α (TNF-α)-induced S1PR2 expression in human umbilical vein endothelial cells (HUVECs) was investigated and the underlying mechanism was explored. The results demonstrated that TNF-α led to an increase in S1PR2 expression and triggered a downregulation of LXR-α expression in HUVECs as well. Downregulation of LXR-α with specific small interfering RNA (siRNA) remarkably enhanced the primary as well as TNF-α-induced expression of S1PR2 in HUVECs. Activation of LXR-α by agonist GW3965 inhibited both primary and TNF-α-induced S1PR2 expression. GW3965 also attenuated S1PR2-induced endothelial barrier dysfunction. The data further showed that TNF-α induced a significant decrease in miR-130a-3p expression. Overexpression of miR-130a-3p with mimic product reduced S1PR2 protein expression, and inhibition of miR-130a-3p by specific inhibitor resulted in an increase in S1PR2 protein expression. Furthermore, activation of LXRs with agonist enhanced the expression of miR-130a-3p, and knockdown of LXR-α by siRNA suppressed miR-130a-3p expression. These results suggest that LXR-α might downregulate S1PR2 expression via miR-130a-3p in quiescent HUVECs. Stimulation of TNF-α attenuates the activity of LXR-α and results in enhanced S1PR2 expression.

Non-rare-earth Mn

Currently, the excitation-wavelength-dependent photoluminescence of traditional carbon dots does not constitute true tuning and their absorptions show gradual attenuation in the visible region. Herein, we report a facile strategy to realize intense visible absorption and full-color emissions of nitrogen doped carbon dots via the control of surface nitriding. The quantum yields of the carbon dots in aqueous solution reached 49.2%, 30.6% and 30.3% for blue, yellow and red emissions, respectively. Structural characterizations and spectroscopic analyses verify that three diverse emitting states, i.e., sp2 carbon core, CO and CN related surface defects, are responsible for the multi-state absorptions and tunable emissions of the carbon dots. The ability to truly tune luminescence into the red wavelength region with strong visible absorption enables these carbon dots to improve the correlated color temperature and color rendering index of traditional phosphor-converted white light-emitting diodes.