Structural Characterization Research Articles

Population Pharmacokinetic-Pharmacodynamic Analysis of a Reserpine-Induced Myalgia Model in Rats.

(1) Background: Fibromyalgia syndrome (FMS) is a chronic pain condition with widespread pain and multiple comorbidities, for which conventional therapies offer limited benefits. The reserpine-induced myalgia (RIM) model is an efficient animal model of FMS in rodents. This study aimed to develop a pharmacokinetic-pharmacodynamic (PK-PD) model of reserpine in rats, linking to its impact on monoamines (MAs). (2) Methods: Reserpine was administered daily for three consecutive days at dose levels of 0.1, 0.5, and 1 mg/kg. A total of 120 rats were included, and 120 PK and 828 PD observations were collected from 48 to 96 h after the first dose of reserpine. Non-linear mixed-effect data analysis was applied for structural PK-PD model definition, variability characterization, and covariate analysis. (3) Results: A one-compartment model best described reserpine in rats (V = 1.3 mL/kg and CL = 4.5 × 10-1 mL/h/kg). A precursor-pool PK-PD model (kin = 6.1 × 10-3 mg/h, kp = 8.6 × 10-4 h-1 and kout = 2.7 × 10-2 h-1) with a parallel transit chain (k0 = 1.9 × 10-1 h-1) characterized the longitudinal levels of MA in the prefrontal cortex, spinal cord, and amygdala in rats. Reserpine stimulates the degradation of MA from the pool compartment (Slope1 = 1.1 × 10-1 h) and the elimination of MA (Slope2 = 1.25 h) through the transit chain. Regarding the reference dose (1 mg/kg) of the RIM model, the administration of 4 mg/kg would lead to a mean reduction of 65% (Cmax), 80% (Cmin), and 70% (AUC) of MA across the brain regions tested. (4) Conclusions: Regional brain variations in neurotransmitter depletion were identified, particularly in the amygdala, offering insights for therapeutic strategies and biomarker identification in FMS research.

Lignin Structural Characterization and Its Antioxidant Potential: A Comparative Evaluation by EPR, UV-Vis Spectroscopy, and DPPH Assays.

The natural aromatic polymer lignin and its lignin-like oligomeric fragments have attracted attention for their antioxidant capacity and free radical scavenging activities. In this study, a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was employed to assess the antioxidant capacity of fractionated and partially depolymerized organosolv lignin by electron paramagnetic resonance (EPR) and UV-Vis spectroscopy. The results show significant antioxidant activity for both the lignin and oligomeric fragments, with the EPR measurements demonstrating their efficiency in quenching the free radicals. The EPR data were analyzed to derive the kinetic rate constants. The radical scavenging activity (RSA) of lignins was then determined by UV-Vis spectroscopy and the results were compared with the EPR method. This two-method approach improves the reliability and understanding of the antioxidant potential of lignin and its derivatives and provides valuable insights for their potential applications in various industries, including pharmaceuticals, food preservation, and cosmetics.

In-situ construction NiS, In(OH)3 and InOOH on the ZnIn2S4 nanosheet for synergistically boosting the photocatalytic H2 evolution

A quaternary nanoflower photocatalyst, NiS/In(OH)3/InOOH/ZnIn2S4, with compact heterojunction, is synthesized through a two-step solvothermal method. NiS, In(OH)3 and InOOH are generated in situ on the surface of ZnIn2S4 nanosheets. Namely, the S of NiS, the In of In(OH)3 and InOOH are directly derived from ZnIn2S4. In addition, the relative amount of In(OH)3 and InOOH in the NiS/In(OH)3/InOOH/ZnIn2S4 composite can be controlled by adjusting the dosage of Ni2+ during the second solvothermal process. The average H2 evolution rate of NiS-ZIS-1 is 1911 μmol·g−1·h−1, approximately 5.1, 2.4, 3.5 times higher than that of ZIS, In(OH)3/InOOH/ZnIn2S4, and NiS/ZnIn2S4, respectively. Structural characterizations, photoelectric property tests, theoretical calculations, and in-situ XPS analyses reveal that the excellent visible light photocatalytic H2 production property of the NiS/In(OH)3/InOOH/ZnIn2S4 composite is due to the synergistic interaction of NiS, In(OH)3 and InOOH. Namely, the in-situ construction of NiS, In(OH)3 and InOOH on the ZnIn2S4 nanosheets can accelerate the electrons migration and improve the charge carriers’ separation efficiency. Meanwhile, the NiS, In(OH)3 and InOOH provide more active sites for the reduction of H+ reduction to H2.

Reversible mechanochromic luminescence in a binuclear zero-dimensional Cd(II) complex through transformation between exciplex and excimer

In this work, the mechanochromic luminescence (MCL) property of a binuclear zero-dimensional cadmium complex with a variety of weak interactions is investigated. It exhibits a reversible transition between blue (445 nm) and yellow-green (470 nm) emission under the alternating treatments of grinding and CH3CN fumigation. The mechanism of MCL is proposed by combining the structural features, characterization results and theoretical calculations. During the grinding process, the ordered stacking of the structural units is disrupted and the crystalline state is transformed into an amorphous state, which is accompanied by a transition of the luminescent center from exciplex to excimer. In addition to exploring the MCL properties of a binuclear cadmium complex, this work provides feasible ideas for studying the response mechanism.

Fully Bio-Based Blends of Poly (Pentamethylene Furanoate) and Poly (Hexamethylene Furanoate) for Sustainable and Flexible Packaging.

In the present study, bio-based polymeric blends have been prepared for applications in the field of sustainable food packaging, starting from two furan-based homopolymers, poly(hexamethylene 2,5-furanoate) (PHF) and poly(pentamethylene 2,5-furanoate) (PPeF). PHF and PPeF were synthesized by two-step melt polycondensation-a solvent-free synthetic strategy-and then binary physical mixtures, PHF/PPeF, with different weight compositions were prepared by dissolution in a common solvent. The blends were processed into compression-moulded films, and molecular, morphological, structural, thermal, and mechanical characterizations were subsequently carried out. Blending did not negatively affect the thermal stability of the parent homopolymers, and good compatibility between them was observed. This strategy also allowed for the modulation of the chain rigidity as well as of the crystallinity, simply by acting on the relative weight amount of the homopolymers. From a mechanical point of view, the presence of PPeF led to a reduction in stiffness and an increase in the elongation at break, obtaining materials with an elastomeric behaviour. Evaluation of the gas barrier properties confirmed that the good barrier properties of PHF were preserved by blending. Finally, lab-scale composting tests confirmed a greater weight loss of the mixtures with respect to the PHF homopolymer.

Study on the influence of cortical bone heterogeneity on the spatio-temporal distribution of drilling temperature

The degree of thermal damage during cortical bone drilling is an important factor in determining the success rate of surgery and postoperative recovery time. In this study, high and low feed rate drilling experiments are carried out on bovine femoral cortical bone by chisel edge thinning drill. Combined with the characterization of cortical bone tissue structure and the measurement results of important thermal property parameters, the potential impact mechanisms of cortical bone heterogeneity on the spatio-temporal distribution of drilling temperature and thermal damage are analyzed. The temperature rise rate and overheating duration at different distances from the hole wall in cortical bone drilling under different feed rates are also compared. The experimental results show that the specific heat gradually increases and the thermal conductivity gradually decreases from the periosteum to the endosteum. The hole wall temperature and thermal diffusion of cortical bone with different tissue structures are different under high and low feed rates. The closer to the cortical bone endosteum, the lower the drilling temperature, thermal diffusion and thermal damage area. This is not only related to the contact time between the drill bit and the hole wall of cortical bone with different tissue structures, but also closely related to the heterogeneous structure of cortical bone. In addition, it is found that in high feed rate cortical bone drilling, the temperature rise rate at different positions from the hole wall is higher and the overheating duration is shorter.

Chemiresistive NO2 sensor: A comparative study of rGO/MCPTPP and rGO/TPTP/MCPTPP composite

This study presents a chemiresistive nitrogen dioxide (NO2) sensor based on reduced graphene oxide (rGO) combined with 5, 10, 15, 20-Tetra-p-tolyl-21 H, 23 H-porphine (TPTP) and 5-(4-Methoxycarbonylphenyl)-10,15,20-triphenyl-21 H,23 H-porphine (MCPTPP). Structural, spectroscopic, morphological, and electrical characterizations of rGO/MCPTPP and rGO/TPTP/MCPTPP were carried out using X-ray diffraction, FTIR, AFM, SEM and current-voltage (I-V) respectively. The flexible ITO-coated electrodes were used to investigate sensing properties. The rGO/TPTP/MCPTPP-based sensor exhibited exceptional selectivity, sensitivity, and reproducibility toward NO2 analytes detection. MCPTPP and TPTP enhanced sensor performance due to their unique interactions with NO2. The rGO/TPTP/MCPTPP sensor exhibited remarkable linearity with a wide dynamic range of 400–100 ppm at (room temperature) RT and remained linear for low concentrations, specifically 35–1 ppm. The sensors also displayed excellent reproducibility over multiple sensing cycles. The superior performance of these sensors makes them promising candidates for various environmental monitoring and industrial applications requiring precise and reliable NO2 detection.

Experimental investigation of kerogen structure and heterogeneity during pyrolysis

Kerogen in shale microstructure plays a vital role in hydrocarbon generation, retention and accumulation. However, characterization of kerogen structure is challenging arguably due to a complex microporous structure and chemical heterogeneity. Thus, the role of kerogen molecular structure in controlling porosity and its heterogeneity, as well as its evolutionary processes, remains unclear. In this study, we investigate the chemical and pore structure of heated kerogen samples by employing a range of characterization tools including gas adsorption experiments, high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FTIR) spectroscopy, and laser Raman experiments for a broad range of pyrolysis temperatures (420–850 °C). Multifractal theory and peak fitting techniques were used to evaluate the controlling mechanisms of kerogen pore structure and heterogeneity. The results suggest that with increasing thermal maturity, the content of oxygen functional groups and long-chain aliphatic groups in kerogen significantly decreases, while the length of aromatic fringes increases and gradually becomes oriented. Furthermore, with increasing thermal maturity, the pore volume of kerogen exhibits a non-monotonic trend, i.e., a decrease, followed by an increase, and then finally a decrease. This is primarily influenced by processes such as hydrocarbon production weakening, secondary hydrocarbon cracking, and carbonization. The heterogeneity and dispersion of meso to macro-sized pores in kerogen increase with temperature, while the connectivity gradually decreases. The chemical structure and spatial distribution of kerogen significantly affect the heterogeneity, connectivity, and dispersion of meso to macro-sized pores. Specifically, high aromaticity, structural disorder, and short aliphatic chains result in enhanced heterogeneity and dispersion of meso to macro-sized pores, reducing pore connectivity. This study thus contributes to a deeper understanding of the evolution of organic matter pores.

Synthesis, Structural Characterization, and Computational Studies of Novel Co(II) and Zn(II) Fluoroquinoline Complexes for Antibacterial and Antioxidant Activities.

Research into heterocyclic ligands has increased in popularity due to their versatile applications in the biomedical field. Quinoline derivatives with their transition metal complexes are popular scaffolding molecules in the ongoing pursuit of newer and more effective bioactive molecules. Subsequently, this work reports on the synthesis and possible biological application of new Zn(II) and Co(II) complexes with a bidentate quinoline derivative ligand (H2 L), [(H2 L):(E)-2-(((6-fluoro-2-((2-hydroxyethyl)amino)quinolin-3-yl)methylene)amino)ethanol]. The ligand and its metal complexes were structurally characterized by spectroscopic methods (1H NMR, 13C NMR, Fourier transform infrared (FTIR), UV-vis, fluorescence, and mass spectroscopy), as well as by thermogravimetric and elemental analysis methods. The spectroscopic findings were further supported by density functional theory (DFT) and time-dependent (TD)-DFT calculations. The biological application was examined by investigating the inhibitory action of the complexes against bacterial strains using diffusion and agar dilution methods, and their profiles against two Gram-positive and Gram-negative bacterial strains were supported by molecular docking analysis. To rationalize the in vitro activity and establish the possible mechanism of action, the interactions and binding affinity of the ligand and complexes were investigated against three different bacterial enzymes (Escherichia coli DNA gyrase (PDB ID 6f86), E. coli dihydrofolate reductase B (PDB ID: 7r6g), and Staphylococcus aureus tyrosyl-tRNA synthetase (PDB ID: 1JIJ)) using AutoDock with the standard protocol. The MIC value of 0.20 μg/mL for zinc complex against E. coli and associated binding affinities -7.2 and -9.9 kcal/mol with DNA gyrase (PDB ID 6f86) and dihydrofolate reductase B (PDB ID: 7r6g), as well as the MIC value of 2.4 μg/mL for cobalt(II) complex against Staphylococcus aureus and the associated binding affinity of -10.5 kcal/mol with tyrosyl-tRNA synthetase (PDB ID: 1JIJ), revealed that the complexes' inhibitory actions were strong and comparable with those of the standard drug in the experiments. In addition, the ability of the new quinoline-based complexes to scavenge 1,1-diphenyl-picrylhydrazyl radicals was investigated; the findings suggested that the complexes exhibit potent antioxidant activities, which may be of therapeutic significance.

Damage kinetics in high-temperature irradiated Ni crystals

High-temperature (∼800 K) ion irradiation with 380 keV Ar ions was used to modify the surface of Ni single crystals in order to generate radiation defects and mimic the effect of neutrons avoiding sample activation. The modified 800 nm thick layer was analyzed regarding structural and mechanical properties utilizing a combination of experimental and simulation techniques. The ion implantation fluence ranged from 1 × 1014 cm−2 up to 1 × 1016 cm−2, which corresponds to values of displacements per atom from 0.25 to 25, respectively. The structural characterization was performed by Rutherford Spectroscopy in Channeling mode (RBS/C) associated with scanning (SEM) and transmission electron microscopy (TEM). The experimental results were supported by Monte Carlo (McChasy) and Molecular Dynamics (MD-LAMMPS) simulations. The simulations performed using the second generation of the McChasy code show that the influence of bubbles formed inside the material is not negligible and affects the quantitative analysis of defects in the simulated spectra. A second step in damage kinetics was revealed for the highest dose (i.e., 25 dpa) as a consequence of the entanglement of dislocations and agglomeration of noble gas bubbles, which was confirmed by TEM analysis. Moreover, nanomechanical results confirm that Ar bubbles deteriorate mechanical properties such as hardness.

Innovative Mamba and graph transformer framework for superior protein-ligand affinity prediction

Accurate measurement of the affinity between drug targets is of great importance in the field of drug discovery, as it provides significant information about drug action. However, the diverse representations of compounds and proteins increase the difficulty of this task. Recently, numerous studies have explored the application of various deep learning methods and architectures in Drug-Target Affinity (DTA) prediction tasks, continuously improving performance. In this work, we present a multimodal late-stage fusion prediction model called MGDTA that combines the pioneering Mamba architecture with a hybrid model architecture based on graph transformers and transformers (GTT). For molecular compounds, structural characterisation is extracted using GTT layers. Additionally, a feature integration module is utilized to obtain molecular features from derived molecular fingerprints, culminating in a unified representation of drug molecules through a feature integration module. For proteins, we adopt the state-space model (SSM) module Mamba to learn feature representations from target protein sequences. This represents a preliminary exploration of the Mamba module in protein sequence feature extraction in DTA tasks. Finally, we predict the results by integrating the feature representations of both molecules and proteins. Our results indicate that the proposed model achieves superior performance on benchmark datasets, validating the feasibility of using the Mamba architecture for DTA tasks. Furthermore, sequence feature visualization demonstrates the capability of the Mamba block to focus on binding site residues within drug targets.

Structural Characterization and Biological Properties Analysis of Exopolysaccharides Produced by Weisella cibaria HDL-4.

An exopolysaccharide (EPS)-producing strain, identified as Weissella cibaria HDL-4, was isolated from litchi. After separation and purification, the structure and properties of HDL-4 EPS were characterized. The molecular weight of HDL-4 EPS was determined to be 1.9 × 10⁶ Da, with glucose as its monosaccharide component. Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) analyses indicated that HDL-4 EPS was a D-glucan with α-(1→6) and α-(1→4) glycosidic bonds. X-ray diffraction (XRD) analysis revealed that HDL-4 EPS was amorphous. Scanning electron microscope (SEM) and atomic force microscope (AFM) observations showed that HDL-4 EPS possesses pores, irregular protrusions, and a smooth layered structure. Additionally, HDL-4 EPS demonstrated significant thermal stability, remaining stable below 288 °C. It exhibited a strong metal ion adsorption activity, emulsification activity, antioxidant activity, and water-retaining property. Therefore, HDL-4 EPS can be extensively utilized in the food and pharmaceutical industries as an additive and prebiotic.

Structural, optical, and detailed photoluminescence characterization of solvothermal synthesized V2O5, ZrO2, and ZrV2O7 nanoparticles

It is indisputable that structural defects are pivotal in modulating the properties of materials. This study provides a comprehensive analysis of the structural, optical, and photoluminescence characteristics of V2O5, ZrO2, and ZrV2O7.These materials were chosen for their potential applications in various key technological domains. The XRD results revealed the formation of high-purity materials with no secondary phases. It was determined that ZrO2exhibits the most significant quantity of structural defects among the investigated materials. The variation in crystallite size as determined by XRD aligns with the variation in grain size observed through Scanning Electron Microscopy (SEM).The optical band gaps of V2O5, ZrO2, and ZrV2O7 were determined to be 2.27 eV, 5.19 eV, and 2.38 eV, respectively. X-ray Photoelectron Spectroscopy (XPS) analysis indicated the presence of constituent elements without any contaminants. A detailed examination of the photoluminescence (PL) emission characteristics in both UV–Vis and near-infrared (NIR) regions for all materials presented broad visible luminescence in the [450–650] nm range under UV excitation. Structural defects are crucial in determining the physico-chemical properties of materials. This is thoroughly examined for V2O5, ZrO2, and ZrV2O7.The infrared (IR) emission spectra, introduced for the first time in this study for V2O5, ZrO2, and ZrV2O7, are employed to elucidate the localization of structural defects within the band gap.

Synthesis and thermoluminescence characterization of either Cu- or Ag-doped lithium triborate

Lithium Triborate (LiB3O5 or LTB), is characterized by chemical stability and good mechanical properties, and it has an effective atomic number (Zeff = 7.39) close to that of the human tissue (Zeff = 7.42), making it a potential dosimeter. The objective of this research is to examine the Thermoluminescence (TL) features and dosimetric characteristics of both Cu-doped and Ag-doped LTB. The material was synthesized using the solid-state synthesis method and four different dopant levels were used for each element (0.1%, 0.5%, 1%, 3%); various techniques such as X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy were used for structural and compositional characterization, for samples annealed at 500 °C for 1 h in all cases. Specific TL features were studied, such as TL glow curve shape, sensitization and sensitivity, fading behavior as well as kinetic characterization using two supplementary techniques, namely fractional glow technique and deconvolution analysis. The effect of each dopant element is different in the (same) lithium triborate matrix in terms of sensitivity. TL dosimetric peaks are yielded for both dopant elements; however, the optimum doping level is 3% for Ag but just 0.1% for Cu. Furthermore, the samples were irradiated at different doses, ranging from 0.5 to 2048 Gy, in order to study the corresponding dose response. A remarkable dose response linearity was observed for the main dosimetric peak of both materials, ranging up to ∼1 kGy.The fading results suggest that LTB doped with 0.1% Cu is the most promising material for dosimetric applications.

Alcohol-bridged dinuclear dysprosium single-molecule magnets

Herein we showcase triple-bridged symmetric dinuclear dysprosium complexes with the core structure of general chemical formula Dy2(L1)2(L2)2(R-OH) (R = Me, 1; Et, 2; iPr, 3; pHCH2, 4) involving bridging alcohol molecules. L1 and L2 represent the deprotonated form of oxazole 4‑tert‑butyl‑2-(7-methoxybenzo[d]oxazol-2-yl)phenol and Schiff-base (E)-2,4-di‑tert‑butyl‑6-((3,5-di‑tert‑butyl‑2-hydroxybenzylidene)amino)phenol, respectively. Single-crystal X-ray structural characterization revealed an unprecedented long Dy-O bond length for the benzyl alcohol analogue. The corresponding long Dy-O bond lengths in 1–4 are 2.7825, 2.6651, 2.6021 and 2.9955 Å, respectively. Alternating current magnetic susceptibility measurements at zero dc field revealed that all four complexes display clear frequency dependence signal peaks, indicating single-molecule magnet behavior. The spin reversal energy barrier heights for 1, 2 and 4 are 31.1, 27.6 and 17.4 K. The dynamic magnetic behavior is influenced by the different Dy-O bond lengths derived from the bridging alcohol molecules. Theoretical calculations were employed to establish magneto-structural correlations in 1–4. Magneto-structural correlations with respect to the alcohol molecule participating in triple-bridged symmetric dinuclear dysprosium complexes is established with the help of quantum-chemical calculations.

Mineralization and stabilization of toxic Pb2+ ions using CMC loaded S/P co-doped biochar composite

Creating more stable chemical precipitates containing lead using biochar composite represents a significant and promising strategy for the treatment of lead contamination. Biochar, a porous and carbonaceous material, was fabricated by pyrolyzing plant biomasses (i.e., soybean straw) under anoxic conditions. In this research, a high capacity of adsorbent called carboxymethyl cellulose-loaded sulfur-phosphorus co-doped biochar composite was prepared, and the optimal lead adsorption parameters and mechanism were also investigated. The experimental results showed that CMC@SP2BC exhibited excellent Pb2+ removal capacity, reaching 829.3 mg/g maximum adsorption under optimum conditions (dosage 0.5 g/L, temperature 308 K, initial pH 5, initial lead concentration 2000 mg/L), which was in agreement with the Langmuir and second-order kinetic models. Moreover, the sequential extraction results indicated that the predominant passivation mechanism for Pb was chemical precipitation, followed by ion exchange, complexation, and physical adsorption. In addition, structural characterization revealed that the passivated lead was mainly in the form of minerals such as PbSO4, Pb3(PO4)2, Pb5(PO4)3OH, and Pb5(PO4)3Cl, which was also further confirmed by PHREEQC model simulation at different pH value and Pb2+ concentrations. Finally, Pb2+ was effectively removed from actual ground water by CMC@SP2BC to achieve Class I and Class II ground water standard. The current work offers an efficient solution for immobilizing Pb2+, which has enormous promise for stabilizing heavy metals.

Preparation and structural characterization of chitosan‑sodium alginate nanocapsules and their effects on the stability and antioxidant activity of blueberry anthocyanins

This study prepared a nanocapsule (NPs) from chitosan (CS) and sodium alginate (ALG) and used them to enhance the stability of blueberry anthocyanins (BA) The optimal NPs was obtained at pH value of 3.25, BA concentration of 0.5 mg/mL and mixing ratio of CS to ALG of 1:1 (W/W). Further, the formation of composite NPs was confirmed by a series of characterization methods. The CS-BA-ALG NPs appeared spherical, smooth, and evenly distributed when observed under an optical microscope and transmission Electron Microscope. The X-ray Diffractometer and Fourier Transform Infrared spectroscopy data proved that electrostatic interaction and hydrogen bonding are dominant forces to form NPs. Thermogravimetric analysis and differential scanning calorimetry results demonstrated that the CS-BA-ALG NPs system significantly improved the thermal stability of anthocyanins. In addition, it was also proved that CS-BA-ALG NPs showed high antioxidant capacity and protection capacity.

SANS investigation of fungal loosenins reveal substrate dependent impacts of protein action on inter-fibril distance and packing order of cellulosic substrates.

Microbial expansin-related proteins include fungal loosenins, which have been previously shown to disrupt cellulose networks and enhance the enzymatic conversion of cellulosic substrates. Despite showing beneficial impacts to cellulose processing, detailed characterization of cellulosic materials after loosenin treatment is lacking. In this study, small-angle neutron scattering (SANS) was used to investigate the effects of three recombinantly produced loosenins that originate from Phanerochaete carnosa, PcaLOOL7, PcaLOOL9, and PcaLOOL12, on the organization of holocellulose preparations from Eucalyptus and Spruce wood samples. Whereas the SANS analysis of Spruce holocellulose revealed an increase in interfibril spacing of neighboring cellulose microfibrils following treatment with PcaLOOL12 and to a lesser extent PcaLOOL7, the analysis of Eucalyptus holocellulose revealed a reduction in packing number following treatment with PcaLOOL12 and to a lesser extent PcaLOOL9. Parallel SEC-SAXS characterization of PcaLOOL7, PcaLOOL9, and PcaLOOL12 indicated the proteins likely function as monomers; moreover, all appear to retain a flexible disordered N-terminus and folded C-terminal region. The comparatively high impact of PcaLOOL12 motivated its NMR structural characterization, revealing a double-psi β-barrel (DPBB) domain surrounded by three α-helices - the largest nestled against the DPBB core and the other two part of loops extending from the core. The SANS analysis of PcaLOOL action on holocellulose samples confirms their ability to disrupt cellulose fiber networks and suggests a progression from reducing microfibril packing to increasing interfibril distance. The most impactful PcaLOOL, PcaLOOL12, was previously observed to be the most highly expressed loosenin in P. carnosa. Its structural characterization herein reveals its stabilization through two disulfide linkages, and an extended N-terminal region distal to a negatively charged and surface accessible polysaccharide binding groove.

Hydrothermal synthesis of SnO2/MoO3-x/rGO ternary nanocomposites as a high-performance anode for lithium ion batteries

The theoretical specific capacity of tin dioxide (SnO2) as a lithium-ion batteries (LIBs) anode material is up to 1494 mAh·g−1, far exceeding that of graphite. However, the low conductivity, volume expansion, crushing failure and particles agglomeration during charge/discharge cycles limit its application in LIBs. In this work, the SnO2/MoO3-x/rGO composite material was synthesized by one-step hydrothermal method, with SnO2 and amorphous MoO3-x tightly and uniformly anchored at the surface of reduced graphene oxide (rGO). The results of structural characterization and electrochemical performance evaluation show that amorphous MoO3-x can increase the reactive active sites, inhibit Sn particles aggregation, and promote the reversible reaction of SnO2. rGO effectively improves the electrical conductivity of the composite and buffers the volume change of Li-Sn alloying/dealloying during cycles. In addition, due to introduction of MoO3-x and rGO a stable SEI film can be formed at the material's surface to improve the cycle stability. SnO2/MoO3-x/rGO exhibits excellent rate performance and cycle performance. When the rGO content is 10.9 wt%, the reversible capacity of the composite reach 813 mAh·g−1 after 800 cycles at current density of 1.0 A·g−1, and 450.6 mAh·g−1 after 1000 cycles at current density of 5.0 A·g−1, with the capacity retention rate of 96.9%.

Activation of H2O2 using a single-atom Cu catalyst for efficient tetracycline degradation

The abuse of antibiotics has caused serious harm to the ecological environment and human health. Fenton-like advanced oxidation technology is a green and effective treatment means, but how to improve the Fenton reaction efficiency and wide pH adaptability is still a big challenge. Herein, we designed and developed a single-atom catalyst Cu1-CN with graphite-phase carbon nitride as the carrier by loading a low amount of metal Cu. The N atom anchors the copper atom in the form of a coordination bond, and the single atom Cu site has excellent performance in activating H2O2. Not only a short period of time (10 min) oxidation degradation of tetracycline (degradation rate 80 %), and in a broad range of pH (3.2 ∼ 9.5) still maintaining high removal performance (efficiency more than 70 %). Combined with X-ray absorption fine structure characterization and density functional theory (DFT) calculations, it is considered that isolated Cu atom and N atom cooperate to construct highly reactive Cu-N4 active centre, which completes the task of H2O2 activation. This study provides a new theoretical basis and technical support for the degradation of antibiotic pollutants by single-atom Fenton-like reaction.