A low-cost process for complete utilization of bauxite residue.

Cost-effective treatment or even valorization of the bauxite residue (red mud) from the alumina industry is in demand to improve their environmental and economic liabilities. This study proposes a strategy that provides a near-complete conversion of bauxite residue to valuable products. The first step involves dilute acid leaching, which allowed the fractionation of raw residues into (1) an aqueous fraction rich in silica and aluminium and (2) a solid residue rich in iron, titanium and rare earth elements. For the proposed process, 91% of the original silicon, 67% of the aluminium, 78% of the scandium and 69% of the cerium were recovered. The initial cost evaluation suggested that this approach is profitable with a gross margin of 167 $US per tonne. This "Residue2Product" approach should be considered for large-scale practices as one of the most economical and sustainable solutions to this environmental and economic liability for the alumina industry.

Scalable Synthesis of Robust MOF for Challenging Ethylene Purification and Propylene Recovery with Record Productivity.

Ethylene (C2H4) purification and propylene (C3H6) recovery are highly relevant in polymer synthesis, yet developing physisorbents for these industrial separation faces the challenges of merging easy scalability, economic feasibility, high moisture stability with great separation efficiency. Herein, we reported a robust and scalable MOF (MAC-4) for simultaneous recovery of C3H6 and C2H4. Through creating nonpolar pores decorated by accessible N/O sites, MAC-4 displays top-tier uptakes and selectivities for C2H6 and C3H6 over C2H4 at ambient conditions. Molecular modelling combined with infrared spectroscopy revealed that C2H6 and C3H6 molecules were trapped in the framework with stronger contacts relative to C2H4. Breakthrough experiments demonstrated exceptional separation performance for binary C2H6/C2H4 and C3H6/C2H4 as well as ternary C3H6/C2H6/C2H4 mixtures, simultaneously affording record productivities of 27.4 and 36.2 L kg-1 for high-purity C2H4 (≥99.9 %) and C3H6 (≥99.5 %). MAC-4 was facilely prepared at deckgram-scale under reflux condition within 3 hours, making it as a smart MOF to address challenging gas separations.

Forager-farmer transition at the crossroads of East and Southeast Asia 4900 years ago.

The southward expansion of East Asian farmers profoundly influenced the social evolution of Southeast Asia by introducing cereal agriculture. However, the timing and routes of cereal expansion in key regions are unclear due to limited empirical evidence. Here we report macrofossil, microfossil, multiple isotopic (C/N/Sr/O) and paleoproteomic data directly from radiocarbon-dated human samples, which were unearthed from a site in Xingyi in central Yunnan and which date between 7000 and 3300 a BP. Dietary isotopes reveal the earliest arrival of millet ca. 4900 a BP, and greater reliance on plant and animal agriculture was indicated between 3800 and 3300 a BP. The dietary differences between hunter-gatherer and agricultural groups are also evident in the metabolic and immune system proteins analysed from their skeletal remains. The results of paleoproteomic analysis indicate that humans had divergent biological adaptations, with and without farming. The combined application of isotopes, archaeobotanical data and proteomics provides a new approach to documenting dietary and health changes across major subsistence transitions.

Active Sites Decorated Nonpolar Pore-Based MOF for One-step Acquisition of C2 H4 and Recovery of C3 H6.

Herein, a 2-fold interpenetrated metal-organic framework (MOF) Zn-BPZ-TATB with accessible N/O active sites in nonpolar pore surfaces was reported for one-step C2 H4 purification from C2 H6 or C3 H6 mixtures as well as recovery of C3 H6 from C2 H6 /C3 H6 /C2 H4 mixtures. The MOF exhibits the favorable C2 H6 and C3 H6 uptakes (>100 cm3 g-1 at 298 K under 100 kPa) as well as selective adsorption of C2 H6 and C3 H6 over C2 H4 . The C3 H6 - and C2 H6 -selective feature were investigated detailedly by experimental tests as well as sorption kinetic studyies. Molecular modelling revealed the multiple interactions between C3 H6 or C2 H6 molecules and methyl groups as well as triazine rings in pores. Zn-BPZ-TATB not only can directly generate 323.4 L kg-1 and 15.4 L kg-1 of high-purity (≥99.9 %) C2 H4 from C3 H6 /C2 H4 and C2 H6 /C2 H4 mixtures, but also provide a large high-purity (≥99.5 %) C3 H6 recovery capacity of 60.1 L kg-1 from C3 H6 /C2 H4 mixtures. More importantly, the high-purity C3 H6 (≥99.5 %) and C2 H4 (≥99.9 %) with the productivities of 38.2 and 12.7 L kg-1 can be simultaneously obtained from C2 H6 /C3 H6 /C2 H4 mixtures through a single adsorption/desorption cycle.

Functional evaluation of epilepsy-associated KCNT1 variants in multiple cellular systems reveals a predominant gain of function impact on channel properties.

OBJECTIVE: Gain of function variants in the sodium-activated potassium channel KCNT1 have been associated with pediatric epilepsy disorders. Here, we systematically examine a spectrum of KCNT1 variants and establish their impact on channel function in multiple cellular systems. METHODS: KCNT1 variants identified from published reports and genetic screening of pediatric epilepsy patients were expressed in Xenopus oocytes and HEK cell lines. Variant impact on current magnitude, current-voltage relationships, and sodium ion modulation were examined. RESULTS: We determined basic properties of KCNT1 in Xenopus oocyte and HEK systems, including the role of extra- and intracellular sodium in regulating KCNT1 activity. The most common six KCNT1 variants demonstrated strong gain of function (GOF) effects on one or more channel properties. Analysis of 36 total variants identified phenotypic heterogeneity but a strong tendency for pathogenic variants to exert GOF effects on channel properties. By controlling intracellular sodium, we demonstrate that multiple pathogenic KCNT1 variants modulate channel voltage dependence by altering the sensitivity to sodium ions. SIGNIFICANCE: This study represents the largest systematic functional examination of KCNT1 variants to date. We both confirm previously reported GOF channel phenotypes and expand the number of variants with in vitro GOF effects. Our data provide further evidence that novel KCNT1 variants identified in epilepsy patients lead to disease through generalizable GOF mechanisms including increases in current magnitude and/or current-voltage relationships.

Facile and Eco-Friendly Approach To Produce Confined Metal Cluster Catalysts.

Zeolite-supported metal nanocluster catalysts have attracted significant attention due to their broad application in heterogeneously catalyzed reactions. The preparation of highly dispersed metal catalysts commonly involves the use of organic compounds and requires the implementation of complicated procedures, which are neither green nor deployable at the large scale. Herein, we present a novel facile method (vacuum-heating) which employs a specific thermal vacuum processing protocol of catalysts to promote the decomposition of metal precursors. The removal of coordinated H2O via vacuum-heating restricts the formation of intermediates (metal-bound OH species), resulting in catalysts with a uniform, metal nanocluster distribution. The structure of the intermediate was determined by in situ Fourier transform infrared, temperature-programmed decomposition, and X-ray absorption spectroscopy (XAS) measurements. This alternative synthesis method is eco-friendly and cost-effective as the procedure occurs in the absence of organic compounds. It can be widely used for the preparation of catalysts from different metal species (Ni, Fe, Cu, Co, Zn) and precursors and is readily scaled-up.

Facilitation of Behavioral and Cortical Emergence from Isoflurane Anesthesia by GABAergic Neurons in Basal Forebrain.

General anesthesia shares many similarities with natural sleep in behavior and electroencephalogram (EEG) patterns. The latest evidence suggests that general anesthesia and sleep-wake behavior may share overlapping neural substrates. The GABAergic neurons in the basal forebrain (BF) have recently been demonstrated to play a key role in controlling wakefulness. It was hypothesized that BF GABAergic neurons may participate in the regulation of general anesthesia. Here, using in vivo fiber photometry, we found that the activity of BF GABAergic neurons was generally inhibited during isoflurane anesthesia, having obviously decreased during the induction of anesthesia and being gradually restored during the emergence from anesthesia, in Vgat-Cre mice of both sexes. Activation of BF GABAergic neurons with chemogenetic and optogenetic approaches decreased sensitivity to isoflurane, delayed induction, and accelerated emergence from isoflurane anesthesia. Optogenetic activation of BF GABAergic neurons decreased EEG δ power and the burst suppression ratio (BSR) during 0.8% and 1.4% isoflurane anesthesia, respectively. Similar to the effects of activating BF GABAergic cell bodies, photostimulation of BF GABAergic terminals in the thalamic reticular nucleus (TRN) also strongly promoted cortical activation and behavioral emergence from isoflurane anesthesia. Collectively, these results showed that the GABAergic BF is a key neural substrate for general anesthesia regulation that facilitates behavioral and cortical emergence from general anesthesia via the GABAergic BF-TRN pathway. Our findings may provide a new target for attenuating the depth of anesthesia and accelerating emergence from general anesthesia.SIGNIFICANCE STATEMENT The basal forebrain (BF) is a key brain region controlling sleep-wake behavior. Activation of GABAergic neurons in the BF potently promotes behavioral arousal and cortical activity. Recently, many sleep-wake-related brain structures have been reported to participate in the regulation of general anesthesia. However, it is still unclear what role BF GABAergic neurons play in general anesthesia. In this study, we aim to reveal the role of BF GABAergic neurons in behavioral and cortical emergence from isoflurane anesthesia and elucidate the underlying neural pathways. Understanding the specific role of BF GABAergic neurons in isoflurane anesthesia would improve our understanding of the mechanisms of general anesthesia and may provide a new strategy for accelerating emergence from general anesthesia.

Plant-Like Tropisms in Artificial Muscles.

Helical plants have the ability of tropisms to respond to natural stimuli, and biomimicry of such helical shapes into artificial muscles has been vastly popular. However, the shape-mimicked actuators only respond to artificially provided stimulus, they are not adaptive to variable natural conditions, thus being unsuitable for real-life applications where on-demand, autonomous operations are required. Novel artificial muscles made of hierarchically patterned helically wound yarns that are self-adaptive to environmental humidity and temperature changes are demonstrated here. Unlike shape-mimicked artificial muscles, a unique microstructural biomimicking approach is adopted, where the muscle yarns can effectively replicate the hydrotropism and thermotropism of helical plants to their microfibril level using plant-like microstructural memories. Large strokes, with rapid movement, are obtained when the individual microfilament of yarn is inlaid with hydrogel and further twisted into a coil-shaped hierarchical structure. The developed artificial muscle provides an average actuation speed of ≈5.2% s-1 at expansion and ≈3.1% s-1 at contraction cycles, being the fastest amongst previously demonstrated actuators of similar type. It is demonstrated that these muscle yarns can autonomously close a window in wet climates. The building block yarns are washable without any material degradation, making them suitable for smart, reusable textile and soft robotic devices.

Dative B←N bonds based crystalline organic framework with permanent porosity for acetylene storage and separation.

The utilization of dative B←N bonds for the creation of crystalline organic framework (BNOF) has increasingly received intensive interest; however, the shortage of permanent porosity is an obstacle that must be overcome to guarantee their application as porous materials. Here, we report the first microporous crystalline framework, BNOF-1, that is assembled through sole monomers, which can be scalably synthesized by the cheap 4-pyridine boronic acid. The 2D networks of BNOF-1 were stacked in parallel to generate a highly porous supramolecular open framework, which possessed not only the highest BET surface area of 1345 m2 g-1 amongst all of the BNOFs but also features a record-high uptake of C2H2 and CO2 in covalent organic framework (COF) materials to date. Dynamic breakthrough experiments demonstrated that BNOF-1 material can efficiently separate C2H2/CO2 mixtures. In addition, the network can be regenerated in organic solvents with no loss in performance, making its solution processable. We believe that BNOF-1 would greatly diversify the reticular chemistry and open new avenues for the application of BNOFs.

Extraordinary Separation of Acetylene-Containing Mixtures in a Honeycomb Calcium-Based MOF with Multiple Active Sites.

Acetylene (C2H2) separation from multicomponent mixtures is vitally important but industrially challenging for the collection of high-purity C2H2. To address this requirement, the reaction between the alkaline-earth Ca2+ ions with a dicarboxylate-diazolate linker, 4,6-di(1H-tetrazol-5-yl)isophthalic acid (H4dtzip), gave rise to a new metal-organic framework (MOF) material [Ca(dtzip)0.5H2O]·2H2O (1). The material presents unique regular tubular channels based on threefolded helical rod-like secondary building units with rich open metal sites and exposed organic hydrogen-bonding N/O acceptors that enhance the interactions with C2H2 molecules, endowing significant selectivity for C2H2 over C2H4 (5.4), C2H6 (5.6), CH4 (30.0), and CO2 (7.7) at 298 K and 100 kPa. Column breakthrough experiments confirmed the extraordinary C2H2 separation performance of the material with the separation time intervals in the range of 18-24 min g-1 for binary (C2H2-C2H4, C2H2-C2H6, C2H2-CO2, and C2H2-CH4) or ternary (C2H2-C2H4-C2H6 and C2H2-C2H4-CO2) gas mixtures under dynamic conditions.

Magnetic Hydrogel Composite for Wastewater Treatment.

Nanocomposite hydrogels are highly porous colloidal structures with a high adsorption capacity, making them promising materials for wastewater treatment. In particular, magnetic nanoparticle (MNP) incorporated hydrogels are an excellent adsorbent for aquatic pollutants. An added advantage is that, with the application of an external magnetic field, magnetic hydrogels can be collected back from the wastewater system. However, magnetic hydrogels are quite brittle and structurally unstable under compact conditions such as in fixed-bed adsorption columns. To address this issue, this study demonstrates a unique hydrogel composite bead structure, providing a good adsorption capacity and superior compressive stress tolerance due to the presence of hollow cores within the beads. The gel beads contain alginate polymer as the matrix and MNP-decorated cellulose nanofibres (CNF) as the reinforcing agent. The MNPs within the gel provide active adsorption functionality, while CNF provide a good stress transfer phenomenon when the beads are under compressive stress. Their adsorption performance is evaluated in a red mud solution for pollutant adsorption. Composite gel beads have shown high performance in adsorbing metal (aluminium, potassium, selenium, sodium, and vanadium) and non-metal (sulphur) contaminations. This novel hybrid hydrogel could be a promising alternative to the conventionally used toxic adsorbent, providing environmentally friendly operational benefits.

Correction: Giant magnetoelectric coupling observed at high frequency in NiFe2O4-BaTiO3 particulate composite.

[This corrects the article DOI: 10.1039/D0RA05782G.].

Phase control of ZIF-7 nanoparticles via mechanochemical synthesis.

Mechanochemical synthesis is a greener synthesis route to form functional metal organic frameworks (MOFs) compared to the typical solvothermal method. Here we demonstrate the crystal phase control of a widely functional zeolitic imidazolate framework, ZIF-7, and its variations via the mechanochemical synthesis route.

Boosting Ethane/Ethylene Separation by MOFs through the Amino-Functionalization of Pores.

Adsorption technology based on ethane-selective materials is a promising alternative to energy-intensive cryogenic distillation for separating ethane (C2 H6 ) and ethylene (C2 H4 ). We employed a pore engineering strategy to tune the pore environment of a metal-organic framework (MOF) through organic functional groups and boosted the C2 H6 /C2 H4 separation of the MOF. Introduction of amino (-NH2 ) groups into Tb-MOF-76 not only decreased pore sizes but also facilitated multiple guest-host interactions in confined pores. The NH2 -functionalized Tb-MOF-76(NH2 ) has increased C2 H6 and C2 H4 uptakes and C2 H6 /C2 H4 selectivity. The results of experimental and simulated transient breakthroughs reveal that Tb-MOF-76(NH2 ) has significantly improved one-step separation performance for C2 H6 /C2 H4 mixtures with a high C2 H4 (>99.95 %) productivity of 17.66 L kg-1 compared to 7.53 L kg-1 by Tb-MOF-76, resulting from the suitable pore confinement and accessible -NH2 groups on pore surfaces.

Regulation of wakefulness by astrocytes in the lateral hypothalamus.

The lateral hypothalamus (LH) is an important brain region mediating sleep-wake behavior. Recent evidence has shown that astrocytes in central nervous system modulate the activity of adjacent neurons and participate in several physiological functions. However, the role of LH astrocytes in sleep-wake regulation remains unclear. Here, using synchronous recording of electroencephalogram/electromyogram in mice and calcium signals in LH astrocytes, we show that the activity of LH astrocytes is significantly increased during non-rapid eye movement (NREM) sleep-to-wake transitions and decreased during Wake-to-NREM sleep transitions. Chemogenetic activation of LH astrocytes potently promotes wakefulness and maintains long-term arousal, while chemogenetic inhibition of LH astrocytes decreases the total amount of wakefulness in mice. Moreover, by combining chemogenetics with fiber photometry, we show that activation of LH astrocytes significantly increases the calcium signals of adjacent neurons, especially among GABAergic neurons. Taken together, our results clearly illustrate that LH astrocytes are a key neural substrate regulating wakefulness and encode this behavior through surrounding GABAergic neurons. Our findings raise the possibility that overactivity of LH astrocytes may be an underlying mechanism of clinical sleep disorders.

Regulation of wakefulness by GABAergic dorsal raphe nucleus-ventral tegmental area pathway.

The dorsal raphe nucleus (DRN) has previously been proved to be involved in the regulation of the sleep-wake behavior. DRN contains several neuron types, such as 5-HTergic and GABAergic neurons. GABAergic neurons, which are the second largest cell subtype in the DRN, participate in a variety of neurophysiological functions. However, their role in sleep-wake regulation and the underlying neural circuitry remains unclear. Herein, we used fiber photometry and synchronous electroencephalogram (EEG)/electromyography (EMG) recording to demonstrate that DRN GABAergic neurons exhibit high activities during wakefulness and low activities during NREM sleep. Short-term optogenetic activation of DRN GABAergic neurons reduced the latency of NREM-to-wake transition and increased the probability of wakefulness, while long-term optogenetic activation of these neurons significantly increased the amount of wakefulness. Chemogenetic activation of DRN GABAergic neurons increased wakefulness for almost 2 h and maintained long-lasting arousal. In addition, inhibition of DRN GABAergic neurons with chemogenetics caused a reduction in the amount of wakefulness. Finally, similar to the effects of activating the soma of DRN GABAergic neurons, optogenetic stimulation of their terminals in the ventral tegmental area (VTA) induced instant arousal and promoted wakefulness. Taken together, our results illustrated that DRN GABAergic neurons are vital to the induction and maintenance of wakefulness, which promote wakefulness through the GABAergic DRN-VTA pathway.

Cerebrolysin alleviates early brain injury after traumatic brain injury by inhibiting neuroinflammation and apoptosis via TLR signaling pathway.

PURPOSE: Traumatic brain injury (TBI) is a major cause of death and disability. Cerebrolysin (CBL) has been reported to be anti-inflammatory by reducing reactive oxygen species (ROS) production. However, the neuroprotection of CBL in TBI and the potential mechanism are unclear. We aimed to investigate the neuroprotection and mechanisms of CBL in TBI. METHODS: The TBI model was established in strict accordance with the Feeney weight-drop model of focal injury. The neurological score, brain water content, neuroinflammatory cytokine levels, and neuronal damage were evaluated. The involvement of the early brain injury modulatory pathway was also investigated. RESULTS: Following TBI, the results showed that CBL administration increased neurological scores and decreased brain edema by alleviating blood­brain barrier (BBB) permeability, upregulating tight junction protein (ZO­1) levels, and decreasing the levels of the inflammatory cytokines tumor necrosis factor­α (TNF­α), interleukin­1ß (IL­1ß), IL­6, and NF­κB. The TUNEL assay showed that CBL decreased hippocampal neuronal apoptosis after TBI and decreased the protein expression levels of caspase­3 and Bax, increasing the levels of Bcl­2. The levels of Toll­like receptor 2 (TLR2) and TLR4 were significantly decreased after CBL treatment. In TBI patients, CBL can also decrease TNF­α, IL­1ß, IL­6, and NF­κB levels. This result indicates that CBL­mediated inhibition of neuroinflammation and apoptosis ameliorated neuronal death after TBI. The neuroprotective capacity of CBL is partly dependent on the TLR signaling pathway. CONCLUSIONS: Taken together, the results of this study indicate that CBL can improve neurological outcomes and reduce neuronal death against neuroinflammation and apoptosis via the TLR signaling pathway in mice.

Induction of the ER stress response in NRVMs is linked to cardiotoxicity caused by celastrol.

Celastrol is a quinone methide triterpenoid extracted from the root bark of Tripterygium wilfordii Hook F, and it exhibits extensive biological activities such as anti-cancer effects. However, narrow therapeutic window together with undesired side effects limit its clinical application. In this study, we explore celastrol's cardiotoxicity using the methods of histology and cell biology. The results show that celastrol administration dose-dependently induces cardiac dysfunction in mice as manifested by left ventricular dilation, myocardial interstitial fibrosis, and cardiomyocyte hypertrophy. Exposure to celastrol greatly decreases neonatal rat ventricular myocyte (NRVM) viability and promotes its apoptosis. More importantly, we demonstrate that celastrol exerts its pro-apoptotic effects through endoplasmic reticulum (ER) stress and unfolded protein response. Furthermore, siRNA targeting C/EBP homologous protein, a pivotal component of ER stress-mediated apoptosis, effectively prevents the pro-apoptotic effect of celastrol. Taken together, our results demonstrate the potential cardiotoxicity of celastrol and a direct involvement of ER stress in the celastrol-induced apoptosis of NRVMs. Thus, we recommend careful evaluation of celastrol's cardiovascular effects when using it in the clinic.

Efficient One-Step Purification of C1 and C2 Hydrocarbons over CO2 in a New CO2-Selective MOF with a Gate-Opening Effect.

Removing CO2 impurity is an essential industrial process in the purification of hydrocarbons. The most promising strategy is the one-step collection of high-purity hydrocarbons by employing CO2-selective adsorbents, which requires improving the CO2 adsorption and separation behavior of adsorbents, especially the low-pressure performance under actual industrial conditions. Herein, we constructed a new flexible metal-organic framework [Zn(odip)0.5(bpe)0.5(CH3OH)]·0.5NMF·H2O (1) (H4odip = 5,5'-oxydiisophthalic acid, bpe = 1,2-bi(4-pyridyl)ethylene, and NMF = N-methylformamide) containing rich ether O adsorption sites in the channels that exhibits remarkable adsorption capacity for CO2 (118.7 cm3 g-1) due to the only gate-opening-type abrupt adsorption of CO2 at room temperature. Its low affinity for other competing gases enables it to deliver high selectivity for the adsorption of CO2 over C1 and C2 hydrocarbons. For equimolar mixtures of CO2-CH4 and CO2-C2H2, the selectivities are 376.0 and 13.2, respectively. Molecular simulations disclose more abundant adsorption sites for CO2 than hydrocarbons in 1. The breakthrough separation performances combined with remarkable stability and recyclability further verify that 1 is a promising adsorbent that can efficiently extract high-purity hydrocarbons through selective capture of CO2.

C2H2 capture and separation in a MOF based on Ni6 trigonal-prismatic units.

A honeycomb MOF, based on rare Ni6 trigonal-prismatic supermolecular building blocks, was fabricated by utilizing an unexploited [1,1'-biphenyl]-3,3',5,5'-tetracarboxylic acid linker with -NH2 substituent groups. The MOF contains novel building blocks and an enchanting structure, and also exhibits water-stable characteristics. Uniquely, the accessible adsorption sites, arising due to the high-density Lewis-basic amino-coordinated groups and uncoordinated carboxylate O atoms in the pores, endow the MOF with excellent capture and separation capabilities for C2H2.