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Pulsed dipolar electron paramagnetic resonance (PD-EPR) measurement is a powerful technique for characterizing the interactions and conformational changes of biomolecules. The extraction of these distance restraints from PD-EPR experiments relies on manipulation of spin–spin pairs. The orthogonal spin labeling approach offers unique advantages by providing multiple distances between different spin–spin pairs. Here, we report an efficient orthogonal labeling approach based on exploiting the cyclization between the 1,2-aminothiol moiety in a protein (e.g., the N-terminal cysteine) with the aldehyde group in a spin label and a thiol substitution (or addition) reaction with a different spin label. We demonstrated that this orthogonal spin labeling method enables high accuracy and precision of multiple protein distance constraints through the PD-EPR measurement from a single sample. This spin labeling approach was applied to characterize the oligomeric state of the trigger factor (TF) protein of Escherichia coli, an important protein chaperone, in solution and cell lysates by distance measurements between different spin–spin pairs. Contrary to popular belief, TF exists mainly in the monomeric state and not as a dimer in the cell lysate.

Reactive sulfur species (RSS) including persulfides (RSSHs), biothiols, and hydrogen sulfide (H2S) are key regulators in various physiological processes. To better understand the symbiotic relationship and interconversion of these RSS, it is highly desirable but challenging to develop analytical techniques that are capable of detecting and quantifying them. Herein, we report the rational design and synthesis of novel trityl-radical-based electron paramagnetic resonance (EPR) probes dubbed CT02-TNB and OX-TNB. CT02-TNB underwent fast sulfur exchange reactions with two reactive RSSHs (PS1 and PS2) which were released from their corresponding donors PSD1 and PSD2 to afford the specific conjugates. The resulting conjugates exhibit characteristic EPR spectra, thus enabling discriminative detection and quantitation of the two RSSHs. Moreover, CT02-TNB showed good response toward other RSS including glutathione (GSH), cysteine (Cys), H2S, and sulfite as well. Importantly, based on the updated EPR spectral simulation program, simultaneous quantitation of multiple RSS (e.g., PS1/GSH/Cys or PS1/GSH/H2S) by CT02-TNB was also achieved. Finally, the levels of released PS1 from PSD1 and endogenous GSH in isolated mouse livers were measured by the hydrophilic OX-TNB. This work represents the first study achieving discriminative and quantitative detection of different persulfides and other RSS by a spectroscopic method.

Traditional physical methods for measuring solubility were often affected by viscosity, density, and surface tension. In this study, we selected appropriate electrolytes to determine the solubility of impurities in the lead-bismuth circuit at reactor operating temperatures using electrochemical methods. Taking the measurement of the solubility of impurity Ce in liquid Bi as an example, we demonstrated that electrochemical methods can accurately determine its solubility in the LiCl-KCl molten salt. Furthermore, the successful measurement of other impurities such as La, Ce, U, and Mn in lead-bismuth eutectic (LBE) using the designed system has confirmed the universality of this method.

Pulmonary arterial hypertension (PAH) is a devastating disease characterized by increased pulmonary vascular resistance and pulmonary arterial pressure. At present, the definitive pathology of PAH has not been elucidated and its effective treatment remains lacking. Despite PAHs having multiple pathogeneses, the cancer-like characteristics of cells have been considered the main reason for PAH progression.

Rubidium (Rb) and cesium (Cs) have important applications in highly technical fields. Salt lakes contain huge reserves of Rb and Cs with industrial significance, which can be utilized after extraction. In this study, a composite magnetic adsorbent (Fe3O4@ZIF-8@AMP, AMP = ammonium phosphomolybdate) was prepared and its adsorption properties for Rb+and Cs+were studied in simulated and practical brine. The structure of the adsorbent was characterized by SEM, XRD, N2adsorption–desorption, FT-IR, and vibrating sample magnetometer (VSM). The adsorbent had good adsorption affinity for Rb+and Cs+. The Langmuir model and pseudo-second-order dynamics described the adsorbing isotherm and kinetic dates, respectively. The adsorption capacity and adsorption rate of Fe3O4@ZIF-8@AMP were increased by 1.86- and 2.5-fold compared with those of powdered crystal AMP, owing to the large specific surface area and high dispersibility of the adsorbent in the solution. The adsorbent was rapidly separated from the solution within 17 s using an applied magnetic field owing to the good magnetic properties. The composite adsorbent selectively adsorbed Rb+and Cs+from the practical brine even in the presence of a large number of coexisting ions. The promising adsorbent can be used to extract Rb+and Cs+from aqueous solutions.

AimsDue to the lack of large clinical cohorts in the Chinese populations with colorectal cancer (CRC) and gastric cancer (GC), there is no consensus among the preferred panel for microsatellite instability (MSI)-PCR testing. This study aims to evaluate a more appropriate panel.MethodsWe tested the MSI status of 2572 patients with CRC and GC using the NCI panel and 2 mononucleotide panels (5 and 6 mononucleotide panels). Immunohistochemistry (IHC) was employed to perform mismatch repair protein testing in 1976 samples.ResultsWe collected 2572 patients with CRC and GC. The National Cancer Institute (NCI) panel failed to detect 13 cases. Of the 2559 cases that received results from all three panels, 2544 showed consistent results. In the remaining 15 cases, 9 showed discrepancies between MSI-H and MSI-L, and 6 showed discrepancies between MSI-L and microsatellite stability (MSS). The misdiagnosis rate of MSI-L was significantly lower in two mononucleotide panels than in the NCI panel (12.5% vs 87.5%, p=0.010) in CRC. In patients with GC, only the NCI panel detected three MSI-L cases, while the results of the two mononucleotide panels were one MSI-H and two MSS. Based on their IHC results, the MSI-L misdiagnosis rate of the NCI panel was 33.3%. Furthermore, compared with two mononucleotide panels, the NCI panel had a much lower rate of all loci instability in CRC (90.8% and 90.3% vs 25.2%) and GC (89.5% and 89.5% vs 12.0%).ConclusionIn Chinese patients with CRC and GC, the five and six mononucleotide panels have advantages for detecting MSI over the NCI panel.

Abstract: The interaction between radionuclides and solid/water interfaces is important to understand the physicochemical processes of radionuclides in the natural environment. Herein, the interaction of 60Co(II) with TiO2 in aqueous solution as a function of pH and ionic strength was studied by using batch technique combined with surface complexation model and density functional theory (DFT) calculations. The batch experimental results showed that the adsorption of 60Co(II) was dependent on pH and independent of ionic strength, indicating the formation of inner-sphere surface complexes on TiO2 surfaces. The results of surface complexation models and DFT calculations indicated that the surface species of 60Co(II) adsorbed on TiO2 followed the trend: B structure (i.e., 60Co(II) was linked to one bridge oxygen site) was the dominant surface species at low pH, and TT structure (i.e., 60Co(II) was linked to two terminal oxygen sites) became the important surface complex at neutral and alkaline pH values. These results demonstrated that a multi-technique approach could lead to definitive information on the structures of adsorbed 60Co(II) at the molecular level at the TiO2/water interfaces, as well as realistic models to rationalize and accurately evaluate the macroscopic manifestations of radionuclide adsorption phenomena.

Phages are prevalent in diverse environments and play major ecological roles attributed to their tremendous diversity and abundance. Among these viruses, transposable phages (TBPs) are exceptional in terms of their unique lifestyle, especially their replicative transposition. Although several TBPs have been isolated and the life cycle of the representative phage Mu has been extensively studied, the diversity distribution and ecological functions of TBPs on the global scale remain unknown. Here, by mining TBPs from enormous microbial genomes and viromes, we established a TBP genome dataset (TBPGD), that expands the number of accessible TBP genomes 384-fold. TBPs are prevalent in diverse biomes and show great genetic diversity. Based on taxonomic evaluations, we propose the categorization of TBPs into four viral groups, including 11 candidate subfamilies. TBPs infect multiple bacterial phyla, and seem to infect a wider range of hosts than non-TBPs. Diverse auxiliary metabolic genes (AMGs) are identified in the TBP genomes, and genes related to glycoside hydrolases and pyrimidine deoxyribonucleotide biosynthesis are highly enriched. Finally, the influences of TBPs on their hosts are experimentally examined by using the marine bacterium Shewanella psychrophilaWP2 and its infecting transposable phage SP2. Collectively, our findings greatly expand the genetic diversity of TBPs, and comprehensively reveal their potential influences in various ecosystems.

Phages are prevalent in diverse environments and play major ecological roles attributed to their tremendous diversity and abundance. Among these viruses, transposable phages (TBPs) are exceptional in terms of their unique lifestyle, especially their replicative transposition. Although several TBPs have been isolated and the life cycle of the representative phage Mu has been extensively studied, the diversity distribution and ecological functions of TBPs on the global scale remain unknown. Here, by mining TBPs from enormous microbial genomes and viromes, we established a TBP genome dataset (TBPGD), that expands the number of accessible TBP genomes 384-fold. TBPs are prevalent in diverse biomes and show great genetic diversity. Based on taxonomic evaluations, we propose the categorization of TBPs into four viral groups, including 11 candidate subfamilies. TBPs infect multiple bacterial phyla, and seem to infect a wider range of hosts than non-TBPs. Diverse auxiliary metabolic genes (AMGs) are identified in the TBP genomes, and genes related to glycoside hydrolases and pyrimidine deoxyribonucleotide biosynthesis are highly enriched. Finally, the influences of TBPs on their hosts are experimentally examined by using the marine bacterium Shewanella psychrophilaWP2 and its infecting transposable phage SP2. Collectively, our findings greatly expand the genetic diversity of TBPs, and comprehensively reveal their potential influences in various ecosystems.

The composition and cellular heterogeneity of the corpus cavernosum (CC) microenvironment have been characterized, but the spatial heterogeneity at the molecular level remains unexplored. In this study, we integrate single-cell RNA sequencing (scRNA-seq) and spatial transcriptome sequencing to comprehensively chart the spatial cellular landscape of the human and rat CC under normal and disease conditions. We observe differences in the proportions of cell subtypes and marker genes between humans and rats. Based on the analysis of the fibroblast (FB) niche, we also find that the enrichment scores of mechanical force signaling vary across different regions and correlate with the spatial distribution of FB subtypes. In vitro, the soft and hard extracellular matrix (ECM) induces the differentiation of FBs into apolipoprotein (APO)+ FBs and cartilage oligomeric matrix protein (COMP)+ FBs, respectively. In summary, our study provides a cross-species and physiopathological transcriptomic atlas of the CC, contributing to a further understanding of the molecular anatomy and regulation of penile erection.

Extraction of uranium from radioactive waste-water is of significant importance for environmental protection and the recovery of uranium resource. Different from the previous reports to use the solid absorbent/photocatalyst for U(VI) removal, herein, we proposed a new eco-friendly method for the rapid and selective extraction of uranium from aqueous solutions under visible light without solid materials. At optimal pH value and in the presence of organics like alcohols, the U(VI) could be extracted efficiently to form brown uranium solid over wide uranium concentrations under anaerobic condition and visible light, by utilizing the excitation of the given U(VI) species. With comprehensive modelling of the electronic ultraviolet-visible (UV-Vis) properties, it is proved that pH adjusting towards U(VI) could induce efficient ligand-to-metal-charge-transfer (LMCT) within the uranyl complex under visible light and the reduction of U(VI) to form U(V), which can be transformed into U(IV) viadisproportionation reaction. The resulting U(IV) in solid phase makes the extraction much more convenient in operation. More importantly, the excellent selectivity for uranium extraction over interfering alkali metal ions, transition metal ions and the lanthanide metal ions shows a powerful application potential.

Brassica napusL. (rapeseed) is one of the most important oil crops with large cultivated area in China. Seed size and seed weight play crucial roles for yield and harvest. In this study, a type of 15 bp-deletion in BnaGRF7.C02coding region was identified through sequence alignment of BnaGRF7.C02in 42 rapeseed varieties, and association analysis indicated that the 15 bp-deletion was related to the rapeseed Thousand-Seed Weight (TSW) phenotype. Furthermore, we developed two InDel markers to identify this 15 bp InDel. The tissue-specific expression patterns showed that BnaGRF7.C02prominently expressed in the late stage of seed development. These findings may assist in InDel markers-based breeding efforts to select higher TWS varieties and improve the crop yield of B. napus.

Mimicking the scheme of incorporating La3+to Pb(Zr1−xTix)O3, Ca2+is used to substitute Na+in the lead-free NaNbO3compound, with A-site vacancy introduced to maintain charge neutrality. The anticipated relaxor behavior is expected to suppress the remanent polarization and improve the energy storage properties of NaNbO3-based ceramics. Specifically, (Na1−2xCax)NbO3(x= 0.01, 0.02, 0.04, 0.08) ceramics were prepared with the solid-state method, and their structures and electric properties were investigated. X-ray diffraction and transmission electron microscopy reveal the existence of minor amount of CaNb2O6second phase. Polarization vs. electric field hysteresis loop measurements verify the suppression of remanent polarization in compositions of x≤ 0.04. The temperature-dependent dielectric tests indicate that both the relaxation and diffuseness parameters monotonically increase with Ca2+content. The results demonstrate that the introduction of a smaller donor dopant and charge-compensating vacancies on the A-site in NaNbO3is an effective strategy to disrupt the long-range dipole order.

Bitumen froth generated from water-based extraction of Alberta oil sands typically consists of 60 wt % bitumen, 30 wt % water, and 10 wt % mineral solids. The froth has to be cleaned by removing the mineral solids and water before it can be upgraded or sold directly to the market. Currently, naphthenic or paraffinic froth treatment processes (NFT or PFT) are used to lower the viscosity of the bitumen froth to facilitate the removal of water and mineral solids. PFT generates a much cleaner bitumen product than NFT through asphaltene precipitation. To induce asphaltene precipitation, the required amount of paraffinic solvent is much higher than that of the naphtha solvent in the NFT process. This increases process complexity and costs in the subsequent solvent recovery process. In this study, the injection of carbon dioxide (CO2) was investigated to assist the PFT process to lower the solvent dosage. It was found that the injection of CO2to dry bitumen–heptane mixtures helped promote asphaltene precipitation when the solvent-to-bitumen ratio was above the onset of asphaltene precipitation. Under moderate CO2pressure (1.7 MPa) and temperature (21–90 °C), the heptane dosage could be reduced by 54.9% while maintaining the same degree of asphaltene precipitation from the dry bitumen. When the solvent-to-bitumen ratio was below the onset, injection of CO2under the tested temperature and pressure did not cause asphaltene precipitation.

One of the main challenges for next-generation electric power systems and electronics is to avoid premature dielectric breakdown in insulators and capacitors and to ensure reliable operations at higher electric fields and higher efficiencies. However, dielectric breakdown is a complex phenomenon and often involves many different processes simultaneously. Here we show distinctly different defect-related and intrinsic breakdown processes by studying individual, single-crystalline TiO2nanoparticles using in situtransmission electron microscopy (TEM). As the applied electric field intensity rises, rutile-to-anatase phase transition, local amorphization/melting, and ablation are identified as the corresponding breakdown processes, the field intensity thresholds of which are found to be related to the position of the intensified field and the duration of the applied bias relative to the time of charged defects accumulation. Our observations reveal an intensity-dependent dielectric response of crystalline oxides at breakdown and suggest possible routes to suppress the initiation of premature dielectric breakdown. Hence, they will aid the design and development of next-generation robust and efficient solid dielectrics.

Under high-pressure conditions, coal chemical looping gasification (CLG) is a potential technology for industrial applications based on its ability to provide clean and efficient conversion of coal to produce syngas. Within the range of 0.1–1.2 MPa, simulations and experiments were carried out as a validation methodology to study the gasification of coal chars with H2O in the presence of Fe2O3/Al2O3as the oxygen carrier (OC) in a fixed-bed reactor. The characteristics of pressurized CLG and the crystalline phase of the reduced OC were investigated by combining the mass transfer model with intrinsic kinetic experiments. The results showed that H2O replenishment and H2removal on the particle surface of coal char by causing the Fe-based OC to undergo reduction, within the mass transfer coefficient Kmamof 0.0015–0.0035 m3mol–1min–1, minimized the concentration gradient between the particle surface and the bulk caused by external diffusion as well as the H2inhibition effect on the surface of coal char particles. The maximum gasification rate of CLG was 2.14 times greater than the gasification rate without OC, and the influence of the coal type on the gasification rate decreased with increasing pressure. The reduced state of the Fe-based OC was Fe3O4at atmospheric pressure, but FeAl2O4appeared when the total pressure was greater than 0.3 MPa, while the average rate of oxygen release slowed significantly, and the maximum oxygen release increased. The deep reduction process of Fe2O3/Al2O3to Fe–Al spinel could significantly enhance the gasification rate of coal char. In addition, an overall kinetic model was established that could describe the variations in the gasification rate with the temperature, pressure, carbon conversion, and lattice oxygen release, including the influence of external diffusion. The simulations reveal the pressured reaction mechanisms of the enhancement of char gasification during CLG with the kinetic model.

Heavy metal pollution, particularly Pb2+, poses a severe threat to human survival and ecosystem health due to its detrimental effects on organisms. Therefore, evaluating the concentration of Pb2+in the environment can help mitigate these risks in advance. In this study, Cu nanoparticles (Cu NPs) modified 2D Cu-Metal-organic frameworks (Cu(NPs)/Cu-MOFs@ITO) are prepared and loaded onto indium tin oxide (ITO) glass by an electrophoretic method to produce an electrochemical sensor (ECS) for Pb2+. Cu(NPs)/Cu-MOF-B was synthesized by a simple solvothermal method and characterized by XRD, SEM, TEM, Raman, FT-IR and other methods to analyze the crystal structure, molecular structure and microstructure. The Cu NPs improve the electron transfer ability, and the abundant surface amino groups of Cu-MOF can be used to bind Pb2+characterized by CVs and EISs. The excellent energy positions of valence and conduction bands of Cu(NPs)/Cu-MOF facilitate the electron migration in oxidation and reduction of Pb2+analyzed by XPS, Mott-Schottky and UV–vis absorption curves. The limit of detection (LOD) reaches 0.065 μM and the sensitivity reaches 99.04 μA μM-1cm-2. The Cu(NPs)/Cu-MOFs@ITO ECS can be successfully applied to detect Pb2+in water environments with high sensitivity, selectivity and reproducibility, which provides a feasible method for detecting Pb2+.

PbZrO3-based antiferroelectric (AFE) ceramics are promising dielectrics for high-energy-density capacitors due to their reversible phase transitions during charge–discharge cycles. In this work, a new composition series, [Pb0.93−xLa0.02(Li1∕2Bi1∕2)xSr0.04][Zr0.57Sn0.34Ti0.09]O3, with Li+and Bi3+substitution of Pb2+at x=0, 0.04, 0.08, 0.12, 0.16 is investigated for the microstructure evolution, ferroelectric (FE) and dielectric properties. It is found that Li+and Bi3+substitution can significantly reduce the sintering temperature and simultaneously enhance the dielectric breakdown strength. An ultrahigh energy efficiency (94.0%) and a large energy density (3.22J/cm3)are achieved in the composition of x=0.12with a low sintering temperature (1075∘C).

Among the unresolved issues in the study of relaxor ferroelectrics is the role of freezing temperature, across which the dynamics of polarization reversal in relaxor ferroelectrics changes. The presence of this freezing temperature is best manifested by the appearance of a double polarization hysteresis loop just above the freezing temperature. Given that the polarization pinching evolving into a double hysteresis starts well below the freezing temperature, there exists a transient temperature regime between the nonergodic and the ergodic relaxor states. To clarify the role of the freezing temperature on the pinching, the polarization reversal near the freezing temperature of relaxor (Pb1-xLax)(Zr1-yTy)1-x/4O3(PLZT) was monitored using three in situelectric field methods: electrocaloric effect, neutron diffraction, and transmission electron microscopy. We demonstrate that the pinching results from a two-step process, 1) domain detexturization in the ferroelectric state and 2) miniaturization of domains. This observation explains the recently reported gap between the depolarization temperature Tdand the ferroelectric-to-relaxor transition temperature TF-Rin lead-free relaxors. We further show that Tdand TF-R, which have long been considered identical in lead-based relaxors, are not the same. The current study suggests that the mismatch between Tdand TF-Ris an inherent feature in both lead-based and lead-free relaxor ferroelectrics.

Dielectric breakdown of oxides is a main limiting factor for improvement of the performance of electronic devices. Present understanding suggests that defects produced by intense voltage accumulate in the oxide to form a percolation path connecting the two electrodes and trigger the dielectric breakdown. However, reports on directly visualizing the process at nanoscale are very limited. Here, we apply in situ transmission electron microscopy to characterize the structural and compositional changes of amorphous TiO2under extreme electric field (∼100 kV/mm) in a Si/TiO2/W system. Upon applying voltage pulses, the amorphous TiO2gradually transformed into crystalline substoichiometric rutile TiO2–xand the Magnéli phase Ti3O5. The transitions started from the anode/oxide interface under both field polarities. Preferred growth orientation of rutile TiO2–xwith respect to the Si substrate was observed when Si was the anode, while oxidation and melting of the W probe occurred when W was the anode. We associate the TiO2crystallization process with the electrochemical reduction of TiO2, polarity-dependent oxygen migration, and Joule heating. The experimental results are supported by our phase-field modeling. These findings provide direct details of the defect formation process during dielectric breakdown in amorphous oxides and will help the design of electronic devices with higher efficiency and reliability.

Lead-free potassium and sodium niobate (KNN) nanofiber webs with random and aligned configurations were prepared by the electrospinning process from polymer-modified chemical solution. The crystallization process, structure, composition, dielectric, ferroelectric, and piezoelectric properties of the nanofibers and nanofiber webs were investigated. Theoretical analysis and experimental results showed that the surface-induced heterogeneous nucleation resulted in the remarkable lower crystallization temperature for the KNN nanofibers with the {100} orientation of the perovskite phase in contrast to the bulk KNN gel and thus well-controlled chemical stoichiometry. Low dielectric loss, large electric polarization, and high piezoelectric performance were obtained in the nanofiber webs. In particular, the aligned nanofiber web exhibited further improved piezoelectric strain and voltage coefficients and higher FOM than their thin film counterparts and is promising for high-performance electromechanical sensor and transducer applications.

Mitochondrial redox homeostasis, the balance between reactive oxygen species and antioxidants such as glutathione, plays critical roles in many biological processes, including biosynthesis and apoptosis, and thus is a potential target for cancer treatment. Here, we report a mitochondrial oxidative stress amplifier, MitoCAT-g, which consists of carbon-dot-supported atomically dispersed gold (CAT-g) with further surface modifications of triphenylphosphine and cinnamaldehyde. We find that the MitoCAT-g particles specifically target mitochondria and deplete mitochondrial glutathione with atomic economy, thus amplifying the reactive oxygen species damage caused by cinnamaldehyde and finally leading to apoptosis in cancer cells. We show that imaging-guided interventional injection of these particles potently inhibits tumour growth in subcutaneous and orthotopic patient-derived xenograft hepatocellular carcinoma models without adverse effects. Our study demonstrates that MitoCAT-g amplifies the oxidative stress in mitochondria and suppresses tumour growth in vivo, representing a promising agent for anticancer applications.

Owing to the increasing popularity of using waste disposal as a source material, inorganic salts such as CaCl2and MgCl2are frequently present in geopolymerization typically taking place in alkali media. Such contaminants influence the dissolution of the aluminosilicate source materials and consequently the properties of the geopolymers made. This work is particularly aimed at elucidating the dissolution mechanism of a well-known clay, namely, kaolinite, in alkali media with the presence of two aforementioned aqueous medium contaminants using molecular dynamics (MD) simulation. A series of MD simulations was carried out on model kaolinite, with its tetrahedral and deprotonated octahedral surfaces exposed to the alkali solutions containing neat Na+or neat K+cations at two concentrations, 3 and 5 M. Different concentrations of CaCl2and MgCl2contaminants (i.e., 0.1, 0.3, and 0.5 M) were added to such alkali solutions. Atomic density profiles show that all cations, including those from the contaminants adsorbed on the two basal surfaces, intensify the dissociation of the aluminate groups from the deprotonated octahedral surface. The dissociation mechanism is somewhat similar to that of the alkali media without contaminants, in which cations weaken the interaction between the aluminum and bridging oxygen atoms. The number of the aluminate groups dissociated decreased with increasing contaminant concentration. In fact, at the highest contaminant concentration used (i.e., 0.5 M), the number of dissociated aluminate groups was even lower than that of the system without contaminants. This observation was attributed to the fact that most of chloride anions remained in the bulk solution at 0.1 M but an increasing amount of chloride ions started to cluster around the cations at 0.5 M, thereby screening the interaction between cations and the deprotonated octahedral surface. As a result, the screening effect reduced the number of aluminate groups dissociated from the surface. Structural analyses of the deprotonated octahedral surface indicated that the crystallinity of the surface decreased with increasing simulation time and alkali solution concentration. No dissolution of the tetrahedral surface was observed for all systems studied.

A series of model compounds for the large components in petroleum, with molecular weights from 534 to 763 g/mol, was thermally cracked in the liquid phase at 365–420 °C to simulate catagenesis over a very short time scale and reveals the selectivity and nature of the addition products. The pyrolysis of three types of compounds was investigated: alkyl pyrene, alkyl-bridged pyrene with phenyl or pyridine as a central ring group, and a substituted cholestane–benzoquinoline compound. Analysis of the products of reaction of each compound by mass spectrometry, high-pressure liquid chromatography, and gas chromatography demonstrated that a significant fraction of the products, ranging from 26 to 62 wt %, was addition products with molecular weights higher than that of the starting compounds. Nuclear magnetic resonance (NMR) spectroscopic analysis showed that the pyrene compounds undergo addition through the attached alkyl groups, giving rise to bridged archipelago products. These results imply that the same geochemical processes that generate the light components of petroleum, such as n-alkanes, simultaneously produce some of the most complex heavy components in the asphaltenes. Similarly, thermal cracking reactions during refinery processes, such as visbreaking and coking, will drive addition reactions involving the alkyl groups on large aromatic compounds.

Nanotube-like Tb-based metal–organic frameworks (Tb-MOFs) were synthesized viathe assembly of carboxylate-based ligands and Tb3+under solvothermal conditions. The porous Tb-MOFs with high stability and considerable active functional groups make them ideal adsorbents in environment remediation. The factors influencing the adsorption property of Tb-MOFs toward Pb2+ions were studied, comprising pH, ionic strength, adsorbent content, initial Pb2+concentration and contact time. The Tb-MOFs exhibited excellent adsorption property with a maximum removal capacity of 547 mg g−1and could maintain a high adsorption performance even after five cycles. Results from batch adsorption experiments and X-ray photoelectron spectroscopy (XPS) analysis imply that the formation of the inner-sphere complex (C–/NPb) between the nitrogenous groups of Tb-MOFs and Pb2+is the primary adsorption mechanism. Furthermore, density functional theory (DFT) calculations confirm that the most favorable adsorption configuration varies with the reaction conditions and deprotonated functional groups tend to bond with Pb2+at high pH. These results suggest that Tb-MOFs could be used as a promising adsorbent for the removal of Pb2+ions from an aqueous environment.

We studied the relative efficacy of different forms of foliar iron (Fe) fertilisation on leaf re-greening in Fe-deficient, purple-fleshed sweet potato (Ipomoea batatas (L.) Lam.) varieties xuzi8 and xuzi6. Activities of ferric chelate reductase (FCR) and concentrations of Fe were measured in the leaves and roots at intervals over 5 days to quantify recovery from leaf chlorosis. Freshly expanded and chlorotic leaves were immersed in one of three different fertiliser compounds containing 9 mm Fe: FeSO4, Fe2(SO4)3, Fe(III)-EDTA. An Fe-sufficient treatment and an Fe-deficient control were included. The experiment had a completely randomised block design with five replications per treatment and was conducted in a sunlit glasshouse. For variety xuzi8, leaf FCR activity in the Fe2(SO4)3 treatment was highest at 1 h after application, and higher than all other treatments, whereas FeSO4 and Fe(III)-EDTA treatments showed their highest FCR at day 5 after application, both significantly higher than the Fe2(SO4)3 and control treatments. Furthermore, leaf Fe concentration reached a maximum in the FeSO4 treatment at day 1, and in the Fe2(SO4)3 treatment at day 3. By contrast, root Fe concentration was relatively constant and lower in the foliar Fe treatments than the Fe-sufficient and -deficient treatments. For variety xuzi6, leaf SPAD was higher with the Fe2(SO4)3 than the FeSO4 treatment at day 5 after application. In general, FCR activity and Fe concentrations in roots and leaves of xuzi6 were higher than those of xuzi8. Variations in leaf Fe concentrations were similar for both the FeSO4 and Fe2(SO4)3 treatments of the two varieties. Maximum leaf Fe levels in xuzi6 were ~4-fold those in xuzi8. The results of the study suggest that foliar-applied Fe2(SO4)3 was the most effective compound at correcting Fe-deficiency symptoms. The higher leaf and root FCR activity and Fe concentration in xuzi6 might explain its higher tolerance to Fe deficiency and better re-greening than xuzi8.

Abstract

Sodium bismuth titanate (NBT) and its solid solutions with other ABO3perovskites are of great interest for lead-free ferroelectric and piezoelectric applications. In this article, we provide an introduction to the complex structure of NBT, including atomic displacements and nanoscale defects. We also review poling effects and properties as well as NBT-ABO3phase equilibria. The interesting relaxor properties, frequency dispersion in dielectric permittivity, and field-induced structural phase transitions of these systems are discussed. Finally, we describe other functional, mechanical, and electrical properties of NBT.

Piezoelectric materials convert between electrical and mechanical energies such that an applied stress induces a polarization and an applied electric field induces a strain. This review describes the fundamental mechanisms governing the piezoelectric response in high-performance piezoelectric single crystals, ceramics, and thin films. While there are a number of useful piezoelectric small molecules and polymers, the article focuses on inorganic materials displaying the piezoelectric effect. Piezoelectricity is first defined, and the mechanisms that contribute are discussed in terms of the key crystal structures for materials with large piezoelectric coefficients. Exemplar systems are then discussed and compared for the cases of single crystals, bulk ceramics, and thin films.

The pyroelectric performance of Pb0.99Nb0.02[(Zr0.57Sn0.43)0.92Ti0.08]0.98O3ceramics was quantified by dielectric, polarization, and specific heat capacity measurements. The tunability of pyroelectric properties upon electric field application was studied as a function of temperature. The large pyroelectric coefficient of 0.28 C m−2K−1was associated with the ferroelectric (FE)–antiferroelectric (AFE) phase transition. The pyroelectric coefficient can be tuned over a broad temperature range of almost 40 K above the zero electric field phase transition. Electrical and thermal measurements were used to estimate various pyroelectric figures of merit. Pyroelectric figures of merit are almost three order of magnitude higher than those previously reported in FE materials. The large pyroelectric properties indicate that the investigated material is a promising candidate for many pyroelectric applications. Temperature‐dependent transitions: The pyroelectric performance of Pb0.99Nb0.02[(Zr0.57Sn0.43)0.92Ti0.08]0.98O3ceramics is quantified by dielectric, polarization, and specific heat capacity measurements. In particular, the tunability of the pyroelectric properties over a wide temperature range upon electric field application is revealed.