E3 ubiquitin ligase NEDD4L negatively regulates skin tumorigenesis by inhibiting of IL-6/GP130 signaling pathway.

Interleukin (IL)-6 signaling plays a crucial role in the survival and metastasis of skin cancer. Neural precursor cell expressed developmentally downregulated 4-Like (NEDD4L) acts as a suppressor of IL-6 signaling by targeting glycoprotein 130 (GP130) degradation. However, the effects of the NEDD4L-regulated IL-6/GP130 signaling pathway on skin cancer remain unclear. In this study, protein expression levels of NEDD4L and GP130 were measured in tumor tissues from patients with cutaneous squamous cell carcinoma (cSCC). Skin tumors were induced in wild type (WT) and Nedd4l knockout (KO) mice, and activation of the IL-6/GP130/STAT3 signaling pathway was detected. The results indicated a negative correlation between the protein expression levels of NEDD4L and GP130 in cSCC tissues from patients. Nedd4l deficiency significantly promoted DMBA/TPA-induced skin tumorigenesis and benign-to-malignant conversion by activating the IL-6/GP130/STAT3 signaling pathway, which was abrogated by supplementation with the GP130 inhibitor SC144. Furthermore, our findings suggested that NEDD4L can interact with GP130 and promote its ubiquitination in skin tumors. In conclusion, our results indicate that NEDD4L could act as a tumor suppressor in skin cancer, and inhibition of GP130 could be a potential therapeutic method for treating this disease.

MB16 - (M = Sc, Y, La): Perfect Bowl-like Boron Clusters.

The introduction of transition-metal doping has engendered a remarkable array of unprecedented boron motifs characterized by distinctive geometries and bonding, particularly those heretofore unobserved in pure boron clusters. In this study, we present a perfect (no defects) boron framework manifesting an inherently high-symmetry, bowl-like architecture, denoted as MB16- (M = Sc, Y, La). In MB16-, the B16 is coordinated to M atoms along the C5v-symmetry axis. The bowl-shaped MB16- structure is predicted to be the lowest-energy structure with superior stability, owing to its concentric (2π+10π) dual π aromaticity. Notably, the C5v-symmetry bowl-like B16- is profoundly stabilized through the doping of an M atom, facilitated by strong d-pπ interactions between M and boron motifs, in conjunction with additional electrostatic stabilization by an electron transfer from M to the boron motifs. This concerted interplay of covalent and electrostatic interactions between M and bowl-like B16 renders MB16- a species of exceptional thermodynamic stability, thus making it a viable candidate for gas-phase experimental detection.

Preparation and functional properties of rice bran globulin-chitooligosaccharide-quercetin-resveratrol covalent complex.

BACKGROUND: As the major protein (approximately 36%) in rice bran, globulin exhibits excellent foaming and emulsifying properties, endowing its useful application as a foaming and emulsifying agent in the food industry. However, the low water solubility restricts its commercial potential in industrial applications. The present study aimed to improve this protein's processing and functional properties. RESULTS: A novel covalent complex was fabricated by a combination of the Maillard reaction and alkaline oxidation using rice bran globulin (RBG), chitooligosaccharide (C), quercetin (Que) and resveratrol (Res). The Maillard reaction improved the solubility, emulsifying and foaming properties of RBG. The resultant glycosylated protein was covalently bonded with quercetin and resveratrol to form a (RBG-C)-Que-Res complex. (RBG-C)-Que-Res exhibited higher thermal stability and antioxidant ability than the native protein, binary globulin-chitooligosaccharide or ternary globulin-chitooligosaccharide-polyphenol (only containing quercetin or resveratrol) conjugates. (RBG-C)-Que-Res exerted better cytoprotection against the generation of malondialdehyde and reactive oxygen species in HepG2 cells, which was associated with increased activities of antioxidative enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) through upregulated genes SOD1, CAT, GPX1 (i.e. gene for glutathione peroxidase-1), GCLM (i.e. gene for glutamate cysteine ligase modifier subunit), SLC1A11 (i.e. gene for solute carrier family 7, member 11) and SRXN1 (i.e. gene for sulfiredoxin-1). The anti-apoptotic effect of (RBG-C)-Que-Res was confirmed by the downregulation of caspase-3 and p53 and the upregulation of B-cell lymphoma-2 gene expression. CONCLUSION: The present study highlights the potential of (RBG-C)-Que-Res conjugates as functional ingredients in healthy foods. © 2024 Society of Chemical Industry.

TMBstable: a variant caller controls performance variation across heterogeneous sequencing samples.

In cancer genomics, variant calling has advanced, but traditional mean accuracy evaluations are inadequate for biomarkers like tumor mutation burden, which vary significantly across samples, affecting immunotherapy patient selection and threshold settings. In this study, we introduce TMBstable, an innovative method that dynamically selects optimal variant calling strategies for specific genomic regions using a meta-learning framework, distinguishing it from traditional callers with uniform sample-wide strategies. The process begins with segmenting the sample into windows and extracting meta-features for clustering, followed by using a pre-trained meta-model to select suitable algorithms for each cluster, thereby addressing strategy-sample mismatches, reducing performance fluctuations and ensuring consistent performance across various samples. We evaluated TMBstable using both simulated and real non-small cell lung cancer and nasopharyngeal carcinoma samples, comparing it with advanced callers. The assessment, focusing on stability measures, such as the variance and coefficient of variation in false positive rate, false negative rate, precision and recall, involved 300 simulated and 106 real tumor samples. Benchmark results showed TMBstable's superior stability with the lowest variance and coefficient of variation across performance metrics, highlighting its effectiveness in analyzing the counting-based biomarker. The TMBstable algorithm can be accessed at https://github.com/hello-json/TMBstable for academic usage only.

Multiple Bonding in AeN- (Ae = Ca, Sr, Ba).

Quantum chemical calculations using ab initio methods at the MRCI+Q(8,9)/def2-QZVPPD and CCSD(T)/def2-QZVPPD levels as well as density functional theory are reported for the diatomic molecules AeN- (Ae = Ca, Sr, Ba). The nature of the bonds is analyzed with a variety of methods. The anions CaN- and SrN- have electronic triplet (3Π) ground states with nearly identical bond dissociation energies De ~57 kcal/mol calculated at the MRCI+Q(8,9)/def2-QZVPPD level of theory. In contrast, the heavier homologue BaN- has a singlet (1Σ+) ground state, which is only 1.1 kcal/mol below the triplet (3Σ-) state. The computed bond dissociation energy of (1Σ+) BaN- is 68.4 kcal/mol. The calculations at the CCSD(T)-full/def2-QZVPPD and BP86-D3(BJ)/def2-QZVPPD levels of theory are in reasonable agreement with the MRCI+Q(8,9)/def2-QZVPPD data except for the singlet (1Σ+) state, which has a large multireference character. The calculated atomic partial charges given by the CM5, Voronoi and Hirshfeld methods suggest small to medium-sized charge donation toward Ae atom Ae←N- for most electronic states. In contrast, the NBO method predicts for all species medium to large electronic charge donation toward nitrogen Ae→N-, which is due to the neglect of the (n)p AOs of Ae atoms as genuine valence orbitals.

Organic-inorganic hybrid ZIF-8/MXene/cellulose-based textiles with improved antibacterial and electromagnetic interference shielding performance.

Despite the tremendous efforts on developing antibacterial wearable textile materials containing Ti3C2Tx MXene, the singular antimicrobial mechanism, poor antibacterial durability, and oxidation susceptibility of MXene limits their applications. In this context, flexible multifunctional cellulosic textiles were prepared via layer-by-layer assembly of MXene and the in-situ synthesis of zeolitic imidazolate framework-8 (ZIF-8). Specifically, the introduction of highly conductive MXene enhanced the interface interactions between the ZIF-8 layer and cellulose fibers, endowing the green-based materials with outstanding synergistic photothermal/photodynamic therapy (PTT/PDT) activity and adjustable electromagnetic interference (EMI) shielding performance. In-situ polymerization formed a MXene/ZIF-8 bilayer structure, promoting the generation of reactive oxygen species (ROS) while protecting MXene from oxidation. The as-prepared smart textile exhibited excellent bactericidal efficacy of >99.99 % against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) after 5 min of NIR (300 mW cm-2) irradiation which is below the maximum permissible exposure (MPE) limit. The sustained released Zn2+ from the ZIF-8 layer achieved a bactericidal efficiency of over 99.99 % within 48 h without NIR light. Furthermore, this smart textile also demonstrated remarkable EMI shielding efficiency (47.7 dB). Clearly, this study provides an elaborate strategy for designing and constructing multifunctional cellulose-based materials for a variety of applications.

3-N-butylphthalide attenuates neuroinflammation in rotenone-induced Parkinson's disease models via the cGAS-STING pathway.

Neuroinflammation is crucial in the onset and progression of dopaminergic neuron loss in Parkinson's disease (PD). We aimed to determine whether 3-N-Butylphthalide (NBP) can protect against PD by inhibiting the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway and the inflammatory response of microglia. MitoSOX/MitoTracker/Hoechst staining was used to detect the levels of mitochondrial reactive oxygen species (ROS) in BV2 cells. Quantitative Real-Time Polymerase Chain Reaction was used to measure the levels of free cytoplasmic mitochondrial DNA (mtDNA) in BV2 cells and mouse brain tissues. Behavioral impairments were assessed using rotarod, T-maze, and balance beam tests. Dopaminergic neurons and microglia were observed using immunohistochemical staining. Expression levels of cGAS, STING, nuclear factor kappa-B (NfκB), phospho- NfκB (p-NfκB), inhibitor of NfκBα (IκBα), and phospho-IκBα (p-IκBα) proteins in the substantia nigra and striatum were detected using Western Blot. NBP decreased mitochondrial ROS levels in rotenone-treated BV2 cells. NBP alleviated behavioral impairments and protected against rotenone-induced microgliosis and damage to dopaminergic neurons in the substantia nigra and striatum of rotenone-induced PD mice. NBP decreased rotenone-induced mtDNA leakage and mitigated neuroinflammation by inhibiting cGAS-STING pathway activation. NBP exhibited a protective effect in rotenone-induced PD models by significantly inhibiting the cGAS-STING pathway. Moreover, NBP can alleviate neuroinflammation, and is a potential therapeutic drug for alleviating clinical symptoms and delaying the progression of PD. This study provided insights for the potential role of NBP in PD therapy, potentially mitigating neurodegeneration, and consequently improving the quality of life and lifespan of patients with PD. The limitations are that we have not confirmed the exact mechanism by which NBP decreases mtDNA leakage, and this study was unable to observe the actual clinical therapeutic effect, so further cohort studies are required for validation.

Integration of metagenome and metabolome analysis reveals the correlation of gut microbiota, oxidative stress, and inflammation in Coilia nasus under air exposure stress and salinity mitigation.

Due to the strong response to air exposure, high mortality was occurred in Coilia nasus. Previous studies reported that 10 ‰ NaCl could significantly reduce mortality in C. nasus under air exposure. To investigate the mechanisms that 10 ‰ NaCl can alleviate stress, community structure and metabolism of the intestinal flora of C. nasus were detected via metagenome and metabolome. In this study, C. nasus were divided into control group (C), air exposure group without 10 ‰ NaCl (AE), and air exposure group with 10 ‰ NaCl (AES). After air exposure stress and salinity mitigation, the mortality, intestinal microorganisms, metabolites, and physiological biomarkers were analyzed. The results showed that the mortality rate of C. nasus was reduced after salinity reduction; the antioxidant capacity was elevated compared to the AE group; and anti-inflammatory capacity was increased in the AES group compared to the AE group. Metagenomic sequencing results showed that the levels of harmful bacteria (E. coli, Aeromonas) in the Candida nasus gut increased after air exposure; beneficial bacteria (Actinobacteria, Corynebacteria) in the C. nasus gut increased after salinity reduction. Metabolomics analyses showed that AE decreased the expression of beneficial metabolites and increased the expression of harmful metabolites; AES increased beneficial metabolites and decreased harmful metabolites. Correlation analysis showed that in the AE group, beneficial metabolites were negatively correlated with oxidative stress and inflammatory response, while harmful metabolites were positively correlated with oxidative stress and inflammatory response, and were associated with bacterial communities such as Gillisia, Alkalitalia, Avipoxvirus, etc.; the correlation of metabolites with oxidative stress and inflammatory response was opposite to that of AE in the case of AES, and was associated with Lentilactobacillus, Cyanobacterium, and other bacterial communities. Air exposure caused damage to Candida rhinoceros and 10 ‰ salinity was beneficial in alleviating C. nasus stress. These results will provide new insights into methods and mechanisms to mitigate stress in fish.

Analysis of the Unusual Chemical Bonds and Dipole Moments of AeF- (Ae=Be-Ba): A Lesson in Covalent Bonding.

Quantum chemical calculations of the anions AeF- (Ae=Be-Ba) have been carried out using ab initio methods at the CCSD(T)/def2-TZVPP level and density functional theory employing BP86 with various basis sets. The detailed bonding analyses using different charge- and energy partitioning methods show that the molecules possess three distinctively different dative bonds in the lighter species with Ae=Be, Mg and four dative bonds when Ae=Ca, Sr, Ba. The occupied 2p atomic orbitals (AOs) and to a lesser degree the occupied 2s AO of F- donate electronic charge into the vacant spx(σ) and p(π) orbitals of Be and Mg which leads to a triple bond Ae F-. The heavier Ae atoms Ca, Sr, Ba use their vacant (n-1)d AOs as acceptor orbitals which enables them to form a second σ donor bond with F- that leads to quadruply bonded Ae F- (Ae=Ca-Ba). The presentation of molecular orbitals or charge distribution using only one isodensity value may give misleading information about the overall nature of the orbital or charge distribution. Better insights are given by contour line diagrams. The ELF calculations provide monosynaptic and disynaptic basins of AeF- which nicely agree with the analysis of the occupied molecular orbitals and with the charge density difference maps. A particular feature of the covalent bonds in AeF- concerns the inductive interaction of F- with the soft valence electrons in the (n)s valence orbitals of Ae. The polarization of the (n)s2 electrons induces a (n)spx hybridized lone-pair orbital at atom Ae, which yields a large dipole moment with the negative end at Ae. The concomitant formation of a vacant (n)spx AO of atom Ae, which overlaps with the occupied 2p(σ) AO of F-, leads to a strong covalent σ bond.

Mulch from lignocellulose as agricultural plastic alternative for sustained-release of photosensitive pesticide.

Extensively used agricultural mulch fabricated from nonbiodegradable polyolefin plastic causes tremendous environmental pollution. In this work, a paper-based mulch, composed of the cellulose fiber networks incorporated with Emamectin benzoate (EB)@sodium lignosulfonate (SL), has been developed with facile papermaking/coating methods. The spherical microcapsule loaded with pesticide EB has a desirable core-shell structure for better protection and sustained release of photosensitive EB. The loading rate and encapsulation efficiency reached 78.5 % and 52.3 %, respectively. Furthermore, microcapsules exhibited excellent slow-release behavior and resistance to photolysis. Natural carnauba wax was coated on the surface of the paper-based mulch to form a hydrophobic layer and increase the physical intertwinement of fibers in the mulch, thereby exhibiting superior performance, such as enhanced tensile strength, excellent hydrophobicity, high air permeability, and high light transmittance at reasonable level. Moreover, unlike conventional polyethylene mulch film, the functionalized paper-based mulch almost completely biodegraded after 75 days in the soil. Thus, multifunctional, eco-friendly mulch from lignocellulose is an innovative approach to obtaining the sustained release of agrochemicals, and it provides an excellent alternative to conventional agricultural plastic mulch.

Facile preparation, optical mechanism elaboration, and bio-imaging application of fluorescent cellulose nanocrystals with tunable emission wavelength.

Interfacing cellulose nanocrystals (CNCs) with fluorescent materials provides more possibilities for constructing of sensory/imaging platforms in biomedical applications. In this work, by harnessing the efficient extraction accompanied modification of CNCs and adjustable optical properties of carbon dots (CDs), we report the constructions and emission wavelength tuning of fluorescent CNCs (F-CNCs) composed of CNC nano-scaffolds and CDs. The as-prepared CNCs are densely decorated with citric acid (CA), which plays the role of carbon source for the in-situ synthesis of CDs on CNCs. For the F-CNCs carrying blue, green, and red emissive CDs, ethylenediamine (EDA), urea, and thiourea are the N or N/S sources. Fingerprints of chemical groups, morphological characters, and redox activities are resolved to elaborate the optical mechanisms of CDs with varying emission colors. The emission wavelength is adjusted by either changing the particle size or introducing new emission centers. Both are primarily achieved via precursor engineering. The F-CNCs reveal quantum yields (QYs) >22 % and negligible fluorescence quenching (< 6 %) upon continuous excitation as long as 24 h. Benefited from their cell membrane penetration capability, the F-CNCs with different emission wavelengths were challenged for multiplexed cytoplasm imaging.

Transition Metal Behavior of Heavier Alkaline Earth Elements in Doped Monocyclic and Tubular Boron Clusters.

Quantum chemical calculations are carried out to design highly symmetric-doped boron clusters by employing the transition metal behavior of heavier alkaline earth (Ae = Ca, Sr, and Ba) metals. Following an electron counting rule, a set of monocyclic and tubular boron clusters capped by two heavier Ae metals were tested, which leads to the highly symmetric Ae2B8, Ae2B18, and Ae2B30 clusters as true minima on the potential energy surface having a monocyclic ring, two-ring tubular, and three-ring tubular boron motifs, respectively. Then, a thorough global minimum (GM) structural search reveals that a monocyclic B8 ring capped with two Ae atoms is indeed a GM for Ca2B8 and Ba2B8, while for Sr2B8 it is a low-lying isomer. Similarly, the present search also unambiguously shows the most stable isomers of Ae2B18 and Ae2B30 to be highly symmetric two- and three-ring tubular boron motifs, respectively, capped with two Ae atoms on each side of the tube. In these Ae-doped boron clusters, in addition to the electrostatic interactions, a substantial covalent interaction, specifically the bonding occurring between (n - 1)d orbitals of Ae and delocalized orbitals of boron motifs, provides the essential driving force behind their highly symmetrical structures and overall stability.

Rotational energy transfer in the collision of N2O with He atom.

The quantum state-to-state rotationally inelastic quenching of N2O by colliding with a He atom is studied on an ab initio potential energy surface with N2O lying on its vibrational ground state. The cross sections for collision energies from 10-6-100 cm-1 and rate constants from 10-5-10 K are calculated employing the fully converged quantum close-coupling method for the quenching of the j = 1-6 rotational states of N2O. Numerous van der Waals shapes or Feshbach resonances are observed; the cross sections of different channels are found to follow the Wigner scaling law in the cold threshold regime and may intersect with each other. In order to interpret the mechanism and estimate the cross sections of the rotational energy transfer, we propose a minimal classical model of collision between an asymmetric double-shell ellipsoid and a point particle. The classical model reproduces the quantum scattering results and points out the attractive interactions and the potential asymmetry can affect the collision process. The resulting insights are expected to expand our interpretations of inelastic scattering and energy transfer in molecular collisions.

Synthesis Strategies, Optical Mechanisms, and Applications of Dual-Emissive Carbon Dots.

Tuning the optical properties of carbon dots (CDs) and figuring out the mechanisms underneath the emissive phenomena have been one of the most cutting-edge topics in the development of carbon-based nanomaterials. Dual-emissive CDs possess the intrinsic dual-emission character upon single-wavelength excitation, which significantly benefits their multi-purpose applications. Explosive exploitations of dual-emissive CDs have been reported during the past five years. Nevertheless, there is a lack of a systematic summary of the rising star nanomaterial. In this review, we summarize the synthesis strategies and optical mechanisms of the dual-emissive CDs. The applications in the areas of biosensing, bioimaging, as well as photoelectronic devices are also outlined. The last section presents the main challenges and perspectives in further promoting the development of dual-emissive CDs. By covering the most vital publications, we anticipate that the review is of referential significance for researchers in the synthesis, characterization, and application of dual-emissive CDs.

Recent Advances in Functional Cellulose-based Films with Antimicrobial and Antioxidant Properties for Food Packaging.

The packaging of food plays a crucial role in food preservation worldwide. However, traditional packaging systems are passive layers with weak efficiency in protecting the food quality. Therefore, packaged foods are gradually spoiled due to the oxidation and growth of microorganisms. Additionally, most of the commercial packaging films are made of petroleum-based materials which raise environmental concerns. Accordingly, the development of eco-friendly natural-derived active packaging systems has increased the attention of scientists. Cellulose as the most abundant polysaccharide on earth with high biocompatibility, no toxicity, and high biodegradability has extensively been applied for the fabrication of packaging films. However, neat cellulose-based films lack antioxidant and antimicrobial activities. Therefore, neat cellulose-based films are passive films with weak food preservation performance. Active films have been developed by incorporating antioxidants and antimicrobial agents into the films. In this review, we have explored the latest research on the fabrication of antimicrobial/antioxidant cellulose-based active packaging films by incorporating natural extracts, natural polyphenols, nanoparticles, and microparticles into the cellulose-based film formulations. We categorized these types of packaging films into two main groups: (i) blend films which are obtained by mixing solutions of cellulose with other soluble antimicrobial/antioxidant agents such as natural extracts and polyphenols; and (ii) composite films which are fabricated by dispersing antimicrobial/antioxidant nano- or microfillers into the cellulose solution. The effect of these additives on the antioxidant and antimicrobial properties of the films has been explained. Additionally, the changes in the other properties of the films such as hydrophilicity, water evaporation rate, and mechanical properties have also been briefly addressed.

China's new urban clusters strategy for coordinated economic growth: Evidence from the sports industry.

In 2014, the Chinese government unveiled the New Urbanization Plan and Document No. 46, which profoundly influenced the development trajectory of the regional economy and sports industry. Using the coupling coordination model, this study aimed to assess the development progress of the sports industry and urban clusters economy. This study sampled Greater Bay Area urban clusters (GBAUC) and Yangtze River Delta urban clusters (YRDUC). The statistics covered one year after the release of the policies to date. We developed a total of 15 macro indicators to evaluate the sports industry and urban cluster economy as two distinct, yet interdependent, economic systems. Using the entropy weight method, we determined the standardized values and weights for the two systems before calculating the coupling coordination degree (D). Between 2015 and 2021, the sampled sports industry and urban clusters economy exhibited coordinated high growth across all economic metrics, with multiple sports industry metrics exhibiting double-digit growth. In 2015, both showed extreme imbalance: D of GBAUC = 0.092, D of YRDUC = 0.091. In 2017, both improved to bare coordination: D of GBAUC = 0.600, D of YRDUC = 0.566. In 2019, both reached well coordination: D of GBAUC = 0.851, D of YRDUC = 0.814. By 2021, both achieved quality coordination: D of GBAUC = 0.990, D of YRDUC = 1. This study provides the first evidence from the sports industry that China's new urbanization model and Document No. 46 are highly effective for synergistic regional economic growth.

Mimicking the C2 molecule: M2B2 and M3B2+ clusters (M = Li, Na) and the reactivity of the N-heterocyclic carbene bound Li2B2 complex.

C2 has attracted considerable attention from the scientific community for its debatable bonding situation. Herein, we show that the global minima of M2B2 and M3B2+ (M = Li, Na) possess similar covalent bonding patterns to C2. Because of strong charge transfer from M2/M3 to B2 dimer, they can be better described as [M2]2+[B2]2- and [M3]3+[B2]2- salt complexes with the B22- core surrounded perpendicularly by two and three M+ atoms, respectively. The energy decomposition analyses in combination with the natural orbital for chemical valence theory give four bonding components in C2, M2B2, and M3B2+ clusters. However, the fourth component does not arise from a bonding interaction but from polarization/hybridization. Considering the effect of Pauli repulsion in σ-space, the attractive covalent interaction in these molecules mainly comes from the two π-bonds. We further presented stable N-heterocyclic carbene (NHC) and triphenylphosphine (PPh3) ligands bound Li2B2(NHC)2 and Li2B2(PPh3)2 complexes. A comparative study of reactivity towards L = CO2, CO, and N2 between Li2B2(NHC)2 and B2(NHC)2 is also performed. L-Li2B2(NHC)2 is highly stable against L dissociation at room temperature for L = CO2 and CO, and the stability is markedly higher than that in L-B2(NHC)2. The larger B2→L π-backdonation in L-Li2B2(NHC)2 also makes L more activated than in L-B2(NHC)2.

Freeze-casting production of thermal insulating and fire-retardant lightweight aerogels based on nanocellulose and boron nitride.

Cellulose aerogels exhibit biocompatibility and biodegradability, rendering them promising candidate for application in building energy conservation and insulation materials. However, the intrinsic inflammability of pristine cellulose aerogel causes unneglectable safety concerns, hindering their application in energy-efficient buildings. Herein, a thermal insulating, fire-retardant, strong, and lightweight aerogel was produced via freeze-casting suspensions of cellulose nanofibril (CNF) and l-glutamine functionalized boron nitride nanosheets (BNNS-g). The aerogel with a BNNS-g:CNF concentration ratio of 15:5 exhibited outstanding mechanical strength owing to the strong interaction between BNNS-g and CNF as well as satisfactory thermal insulating performance (0.052 W/m·K). Particularly, this aerogel showed excellent fire-retardant and self-extinguishing capabilities in the vertical burning test, which remained unscathed after over 60 s of burning in a butane flame. Further, the limit oxygen index (LOI) of this aerogel was 36.0 %, which was better than the LOIs of traditional petrochemical-based insulating materials. This study provides a promising strategy for producing aerogels with excellent properties using cellulose and other inorganic nano-fillers.

Experimental Study on the Dynamic Fracture Characteristics of Mortar-Rock Interface Zones with Different Interface Inclinations and Shapes.

There has been little research on the impact resistance of mortar-rock slope protection structures. To ensure that the mortar-rock interface has good adhesion properties under the action of impact loading, in this paper, based on fracture mechanics theory, a theoretical impact model was established for mortar-rock binary material. Dynamic fracture tests were carried out on mortar-rock interfaces using the split-Hopkinson pressure bar (SHPB) system. The Brazilian disc (CSTBD) specimen was prepared with one half in granite and the other half in mortar. The specimen used for the dynamic impact test was 48 mm in diameter and 25 mm thick. The effects caused by the change in interface inclination and interface shape on the dynamic fracture mode were discussed. The dynamic model parameters were obtained for different inclination angles and interfaces. The results show that both the interface inclination and interface shape have significant effects on the dynamic mechanical properties of the mortar-rock binary material. The fracture modes of the mortar-rock specimens can be classified into three types. When the interface inclination is 0°, the specimen shows shear damage with an interface fracture; when the interface inclination is in the range of 0-90°, the dynamic splitting strength of the mortar-rock material increases with increasing interface inclination, and the interface undergoes composite fracture; and when the interface inclination is 90°, the dynamic splitting strength of the specimen reaches its peak, and the interface undergoes tensile fracture. The mortar-rock interface damage follows the M-C criterion. The roughness of the interface shape has a large influence on the dynamic splitting strength of the specimens. The rougher the interface shape, the higher the interface cleavage strength and the higher the peak load that causes the material to damage. The results of this study can provide a reference for the design of mortar-rubble structures to meet the demand for impact resistance and have strong engineering application value.

Clusters and bulky Lewis acid protected complexes with planar hexacoordinate beryllium and magnesium.

Planar hexacoordination (ph) is only rarely reported in the literature. So far, only a few neutral and cationic molecules possessing phE (E = C, Si, B, Al, Ga) in the most stable isomer are predicted theoretically. Present electronic structure calculations report hitherto unknown anionic planar hexcoordinate beryllium and magnesium, phBe/Mg, as the most stable isomer. Global minimum searches show that the lowest energy structure of BeC6M3- (M = Al, Ga) and MgC6M3- (M = Ga, In, Tl) is the D3h symmetric phBe/Mg clusters, where beryllium/magnesium is covalently bonded with six carbon centers and M is located in a bridging position between two carbon centers. These global minimum phBe/Mg clusters are highly kinetically stable against isomerization, facilitating the experimental confirmation by photoelectron spectroscopy. Noteworthy is the fact that the phBe/Mg center is linked with carbon centers through three 7c-2e delocalized σ bonds and three 7c-2e π bonds, making the cluster double aromatic (σ + π) in nature. The bonding between the Be/Mg and outer ring moiety can be best expressed as an electron-sharing σ-bond between the s orbital of Be+/Mg+ and C6M32- followed by three dative interactions involving empty pπ and two in-plane p orbitals of Be/Mg. Furthermore, Lewis basic M centers of the title clusters can be passivated through the complexation with bulky Lewis acid, 9-boratriptycene, lowering the overall reactivity of the cluster, which can eventually open up the possibility of their large-scale syntheses.