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By substituting boron atoms for selected carbon atoms of a graphene quantum dot (GQD) model, namely a coronene molecule, the substituent effect on its geometric and electronic structure, as well as nonlinear optical response has been systemically investigated in theory. Our computations reveal that the boron substitution leads to a similar noncentrosymmetric apophysis structure for the boron-substituted coronene in singlet and triplet states. Noticeably, due to the small energy difference of 2.5 kcal mol-1 between the singlet and triplet states, the boron-substituted molecule can easily be switched between the antiferromagnetic (singlet state) and ferromagnetic (triplet state) state by slightly changing the external conditions. Notably, the boron-substituted coronene exhibits a considerably large first hyperpolarizability of 36241 au, because boron substitution yields a raised structure with an intermediate singlet diradical character. Hence, it is expected that this study not only provides new insights for the boron-substituent effect on the structure and properties of graphene but also may promote practical applications of GQDs in the fields of spintronics and nonlinear optics.

The possibility to design new superatom species by decorating Zintl polyanions with alkali metal cations has been examined under density functional theory in this work. Utilizing typical Zintl ions as examples, MLin+1+ cations have been constructed and investigated in detail. Calculations show that all of the Zintl anions Mn− preserve their geometric and electronic integrity in the global minima of MLin+1+ cations. The stability of these studied cations is guaranteed by the strong ionic bonds between the Zintl core and ligands, as well as their large HOMO−LUMO gaps and positive dissociation energies with respect to the loss of a Li+ cation. In particular, all these proposed cations possess pretty low vertical electron affinities, verifying their superalkali or pseudoalkali identities. Besides, the feasibility of using these proposed MLin+1+ cations as building blocks to design new superatom compounds is explored by theoretically constructing and charactering two series of MLin+1−(super)halogen compounds. We, therefore, hope that this work will not only provide an approach to obtain new superatoms by utilizing various Zintl polyanions as the central cores, but also offer new building blocks for cluster-assembled nanomaterials in which exceptionally strong reducing matters are required.

It has recently been demonstrated that oriented external electric fields (OEEFs) can serve as future smart reagents and effectors in chemistry. Consequently, the effect of OEEFs on the geometric structures, electronic properties, bonding properties, and NLO responses of three typical superatom compounds, i.e., (NLi4)(BF4) and (BLi6)X (X = BeF3 and BF4) has been systemically investigated by ab initio computations in this work. The computational results reveal that the (NLi4)(BF4) possesses almost the same performance as the traditional alkali metal halide under the same OEEFs. It is found that the vertical ionization potential, bond energy, and first hyperpolarizability of (NLi4)(BF4) can be gradually enhanced by increasing the imposed OEEF from zero to the critical external electric field (Fc) along the charge transfer direction (NLi4 → BF4). In particular, the first hyperpolarizability of (NLi4)(BF4) is greatly enlarged from 2.84 × 103 to 1.36 × 107 au (4790-fold) by increasing OEEF from 0 to 121 × 10–4 ...

A novel fluorescence resonance energy transfer (FRET)-based aptasensor was proposed for carcino-embryonic antigen (CEA) detection utilizing NaYF4:Yb3+, Er3+ upconversion nanoparticles (UCNPs) and gold nanoparticles (Au-NPs) as the energy donor and acceptor, respectively. The FRET process occurs when the single-stranded DNA modified UCNPs and Au-NPs are linked together by the CEA aptamer, which leads to the fluorescence quenching of UCNPs. However, the presence of CEA splits the above fluorescence-suppressed Au-NPs–aptamer–UCNPs sandwich complex, resulting in the fluorescence recovery of UCNPs. The recovery of fluorescence intensity is linearly correlated to the concentration of CEA in the range of 0.05–2.0 ng mL−1, enabling the detection and quantification of CEA. Such a sandwich-type FRET-based assay possesses a low limit of detection (0.02 ng mL−1) and satisfactory selectivity and reproducibility, indicating that this biosensor is applicable for the trace detection of the CEA protein.

The potential application of all-boron fullerene B40 as a drug carrier for anti-cancer nitrosourea (NU) has been explored by the means of density functional theory (DFT). Our results reveal that the NU drug tends to combine with the corner boron atom of B40 cage via its oxygen and nitrogen atoms with a moderate adsorption energy of −25.18 kcal/mol. Herein, the newly formed B-O and B-N bonds are proved to be strong polar covalent bonds by atoms in molecules (AIM) theory, localized molecular orbital (LMO), and electron localization function (ELF) analyses. A short recovery time of 52 s is predicted for the NU desorption process at 310.15 K, indicating that the desorption of NU from B40 is easy under body temperature. Moreover, it is found that B40 can simultaneously adsorb up to five NU drugs, exhibiting a high loading capacity. Finally, the substituent effect of C, N, Al, and Ga atoms on the drug delivery performance of this B40 nanocage has been considered. Our results not only suggest that B40 has a great potential to be used in drug delivery, but also signify that the substituent effect of foreign atoms can be employed to modulate the drug adsorption performance of B40.

The first synthesis of facially polarized all-cis-1,2,3,4,5,6-hexafluorocyclohexane (1) was a tour de force of organic chemistry and opened up new possibilities for molecular design. In view of its large facial polarization, 1 was first utilized as a complexant to design a series of organic alkalides, namely M+·1·M′– (M, M′ = Li, Na, K), in this work. The alkalide identities of these proposed species were guaranteed by their HOMOs and VIE values, as well as NBO analysis. Our computational results show that these novel alkalides possess large complexation energies and thus exhibit high stability due to the strong electrostatic interaction between the alkali-metal ions and the axial fluorine or hydrogen atoms of 1. In particular, it is revealed that these novel alkalides possess remarkably large nonlinear optical responses with the first hyperpolarizabilities (β0) up to 1.45 × 106 au. Moreover, the feasibility of using 1 to design superalkali-based alkalide and superalkalide was also examined. We hope that ...

Alkalides, as a representative kind of excess electron compounds, have been demonstrated to be potential nonlinear optical (NLO) materials with large static first hyperpolarizabilities (β0). The possibility of utilizing coinage metal atoms as a novel excess electron source to design a series of alkalides, i.e., (M@36adz)M′ (M = Cu, Ag, and Au; M′ = Li, Na, and K), was examined by density functional theory calculations. The alkalide characteristics of these compounds are guaranteed by their HOMOs and VIE values as well as NBO analysis. In particular, all proposed alkalides exhibit considerable first hyperpolarizabilities (β0) up to 61 590 au, indicating that they can be considered as novel NLO molecules of high performance. Moreover, a larger cage-complexant has been considered, and the resulting (Ag+@TriPip222)K– alkalide possesses a remarkably large β0 value of 180 068 au. We hope that this work will provide a new recipe for designing excess electron compounds and, on the other hand, attract more researc...

The geometric structures, energetic and electronic properties of global minima of the AlBe n ( n = 1–12) clusters have been systemically studied by using the hybrid density functional theory [B3LYP] and coupled cluster [CCSD(T)] methods. It is found that the impurity Al atom is externally bound to the host Be n framework and its maximum coordination number is six. Besides, the geometries of AlBe n bear close resemblance to either local or global minimum structures of Be n +1 . The AlBe 3 and AlBe 8 clusters exhibit high relative stability among the AlBe n clusters, which is reflected by the evolutions of average atomic binding energy, dissociation energy, second difference in energy, adsorption energy of Al, and HOMO-LUMO gap with cluster size. In comparison to the pure Be n +1 clusters, AlBe n exhibit larger binding energy values, whereas they are more polarizable.

Donor-linker-acceptor (D-L-A)-based photoinduced electron transfer (PET) has been frequently used for the construction of versatile fluorescent chemo/biosensors. However, sophisticated and tedious processes are generally required for the synthesis of these probes, which leads to poor design flexibility. In this work, by exploiting a Schiff base as a linker unit, a covalently bound D-L-A system was established and subsequently utilized for the development of a PET sensor. Cysteamine (Cys) and N-acetyl-l-cysteine (NAC) costabilized gold nanoclusters (Cys/NAC-AuNCs) were synthesized and adopted as an electron acceptor, and pyridoxal phosphate (PLP) was selected as an electron donor. PLP can form a Schiff base (an aldimine) with the primary amino group of Cys/NAC-AuNC through its aldehyde group and thereby suppresses the fluorescence of Cys/NAC-AuNC. The Rehm-Weller formula results and a HOMO-LUMO orbital study revealed that a reductive PET mechanism is responsible for the observed fluorescence quenching. Since the pyridoxal (PL) produced by the acid phosphatase (ACP)-catalyzed cleavage of PLP has a weak interaction with Cys/NAC-AuNC, a novel turn-on fluorescent method for selective detection of ACP was successfully realized. To the best of our knowledge, this is the first example of the development of a covalently bound D-L-A system for fluorescent PET sensing of enzyme activity based on AuNC nanoprobes using a Schiff base.

Compared with plenty of single-functional molecules, multifunctional molecules are scarce and have high demand in further research. In this work, a multifunctional molecule called 10-methyl-2-amino-acridone (MAA) is presented. Interestingly, MAA simultaneously features electrochemistry, two-photon fluorescence, visible-light-induced oxidase mimic, and photoelectrochemistry (PEC) activity, and the related properties are studied in detailed. Multiple functions integrated into one molecule allow MAA to become a versatile signal probe. Therefore, the MAA acted as an electrochemical indicator to detect exosomal total protein with high sensitivity at first. In addition, MAA is used for one- or two-photon fluorescence imaging in vitro and in vivo, including cells, three-dimensional (3D) tumor spheroids, zebrafish, and exosomes. The results suggest that MAA not only possesses favorable photostability, but it is also suitable for imaging in deep tissue. Furthermore, the visible-light-induced oxidase mimic and photoelectrochemical activities of MAA are selectively inhibited by Cu2+, and the relevant mechanism is carefully analyzed. On the basis of this phenomenon, we develop a dual-modal detection strategy for detection of Cu2+ in river water. Compared with a single signal readout model, this strategy is able to avoid false positive and negative detection through two series of data mutually validating each other. Therefore, our study shows that the "multiple-in-one" MAA provides a blueprint for the investigation and application of a multifunctional organic molecule.

Superalkalis are clusters or molecules featuring lower ionization energies (IEs) than that of cesium atoms, and thus exhibit excellent reducing properties. Such special species have great potential to be used in the synthesis of unusual charge-transfer salts and cluster-assembled nanomaterials with tailored properties, in the reduction of carbon dioxide, or as hydrogen storage materials and noble-gas-trapping agents, etc. In this regard, ongoing efforts have been devoted to designing and characterizing superalkalis of new types. The recent progress on the study of superalkalis in terms of theoretical design, characterization, and potential application is summarized in this minireview. We hope this review will not only provide a broad overview of this research field, but also highlight the prospect of further extending the experimental synthesis and practical application of superalkalis.

Design of high-performance all-inorganic halide perovskites, especially lead-free perovskites, is key to the broadening of its application prospects. Herein, the authors report the synthesis of ligand-free cesium platinum (IV) bromide nanocrystals (Cs2 PtBr6 NCs), a new kind of vacancy-ordered lead-free perovskite nanomaterial, by a facile one-pot method. The Cs2 PtBr6 NCs exhibits a narrow band gap of 1.32 eV covering the entire visible range, which is supported by density functional theory calculations. Together with their high conductivity, matching energy levels with the work function of carbon electrodes, and excellent environmental stability, this NC displays a cathodic photocurrent density as high as 335 µA cm-2 , two orders of magnitude higher than other perovskites in aqueous solutions without the need of other electron acceptors. These combined properties suggest that the Cs2 PtBr6 NCs have great potentials in a wide range of photoelectronic and photoelectrochemical sensing applications.

Currently, organic artificial enzymes as biocatalysts have been extensively used to construct various colorimetric sensors. However, exploiting a potential organic artificial enzyme with high catalytic efficiency still remains a challenge. To address this issue, herein, we synthesize an acridone derivative 10-benzyl-2-amino-acridone (BAA). The synthesized BAA exhibits an intrinsic visible-light-stimulated oxidase-like activity, which is capable of oxidizing various chromogenic substrates without destructive hydrogen peroxide (H2O2) under visible light stimulation, resulting in colored products. The reaction system can be regulated by switching light on and off, which is milder and more reliable means than others H2O2-dependent. The photocatalytic mechanism of BAA is investigated in detail. However, l -ascorbic acid (AA), an antioxidant generating from the acid phosphatase (ACP)-mediated hydrolysis of 2-phospho- l -ascorbic acid (AAP), is able to inhibit the catalytic activity of BAA. Based on the above properties, a facile, photo-switchable and low-cost colorimetric sensing strategy is developed for ACP detection. The linear range is 0.05–2.5 U/L (r = 0.9994), and the limit of detection (LOD) is 0.0415 U/L. Moreover, the proposed sensing system can be applied for monitoring ACP activity in practical samples, demonstrating promising applications in clinical analysis and biosensor platform.

The geometric structures, energetic and electronic properties of the AlBen (n = 1–12) clusters have been systemically studied by using the hybrid density functional theory [B3LYP] and coupled cluster [CCSD(T)] method. It is found that the impurity Al atom is externally bound to the host Ben framework and its maximum coordination number is six. Besides, the geometries of AlBen bear close resemblance to the minimum structures of Ben+1. The AlBe3 and AlBe8 clusters exhibit high relative stability among the AlBen clusters, which is reflected by the evolutions of average atomic binding energy, dissociation energy, second difference in energy, adsorption energy of Al, and HOMO-LUMO gap with cluster size. In comparison to the pure Ben+1 clusters, AlBen exhibit larger binding energy values, whereas they are more polarizable.

The equilibrium structures, stability and magnetic properties of Sc(BO2)n−/0 (n = 1–4) clusters were investigated on the basis of density functional theory calculations. The BO2 ligands prefer to stretch out in the most stable Sc(BO2)n− anions but tend to come together in the lowest-lying Sc(BO2)4 structure. According to the MP2 results, the Sc(BO2)4− species could be classified as hyperhalogen anions since they have larger vertical electron detachment energies (VDEs, 5.44–8.85 eV) than that of the superhalogen anion BO2−. With titanium and vanadium playing the role of central atom, the Ti(BO2)n−/0 (n = 1–5) and V(BO2)n−/0 (n = 1–6) clusters were studied in a similar manner. In these cases, the central transition metal atoms are inclined to keep their intrinsic spin. In addition, the hyperhalogen identity of the Ti(BO2)n− (n = 4, 5) and V(BO2)n− (n = 3–6) species were also confirmed by the calculated VDE values.

Excess-electron compounds can be considered as novel candidates for nonlinear optical (NLO) materials because of their large static first hyperpolarizabilities (β0 ). A room-temperature-stable, excess-electron compound, that is, the organic electride Na@(TriPip222), was successfully synthesized by the Dye group (J. Am. Chem. Soc. 2005, 127, 12416). In this work, the β0 of this electride was first evaluated to be 1.13×106 au, which revealed its potential as a high-performance NLO material. In particular, the substituent effects of different substituents on the structure, electride character, and NLO response of this electride were systemically studied for the first time by density functional theory calculations. The results revealed that the β0 of Na@(TriPip222) could be further increased to 8.30×106 au by introducing a fluoro substituent, whereas its NLO response completely disappeared if one nitryl group was introduced because the nitro-group substitution deprived the material of its electride identity. Moreover, herein the dependence of the NLO properties on the number of substituents and their relative positions was also detected in multifluoro-substituted Na@(TriPip222) compounds.

Guided by density functional theory (DFT) computations, a new series of superalkali-based alkalides, namely FLi2 (+) (aza222)K(-) , OLi3 (+) (aza222)K(-) , NLi4 (+) (aza222)K(-) , and Li3 (+) (aza222)K(-) were designed with various superalkali clusters embedded into an aza222 cage-complexant. These species possess diverse isomeric structures in which the encapsulated superalkalis preserve their identities and behave as alkali metal atoms. The results show that these novel alkalides possess larger complexation energies and enhanced hyperpolarizabilities (β0 ) compared with alkali-metal-based and previous superalkali-based clusters. Especially, a prominent structural dependence of β0 is observed for these studied compounds. Hence, the geometric factors that affect the nonlinear optical (NLO) response of such alkalides is elucidated in detail in this work. This study not only provides novel candidates for alkalides, it also offers an effective way to enhance the NLO response and stability of alkalides.

We have read Char's comment1. Thanks for readers’ attention and valuable feedback on our article. Following was our response to Char's question about data overlap.Firstly, the meta‐analysis reprocessed the existing data about COVID‐19 patients in published articles, and involved no other information outside of the article.This article is protected by copyright. All rights reserved.

To investigate the recovery of protective effects of exogenous hydrogen sulfide (HH9C2 cells (cardiomyocytes line) were treated with 30 μmol/L hydrogen peroxide (HThirty μmol/L HExogenous H

The potential application of the jellium model as guidance in the rational design of bimetallic superalkali cations is examined under gradient-corrected density functional theory for the first time. By using Li, Mg, and Al as atomic building blocks, a series of bimetallic cationic clusters with 2, 8, 20, and 40 valence electrons are obtained and investigated. As the corresponding neutral clusters tend to lose one valence electron to achieve closed-shell states in the jellium model, these studied cations exhibit much lower vertical electron affinities (EAvert , 3.42-4.95 eV) than the ionization energies (IEs) of alkali metal atoms, indicating their superalkali identities. The high stability of these cationic clusters is guaranteed by their considerable HOMO-LUMO gaps and binding energies per atom. Moreover, the feasibility of using the designed superalkalis as efficient reductants to activate CO2 and N2 molecules and as stable building blocks to assemble ionic superatom compounds is explored. Therefore, this study may provide an effective method for obtaining various metallic superatoms with extensive applications on the basis of the simple jellium rule.

Recently, cancer research microRNA studies have drawn great attention. However, the results of these studies have been inconsistent and variable regarding the availability of circulating miRNAs in gastric cancer (GC) diagnosis. Thus, results should be interpreted cautiously. The purpose of the present study was to assess the diagnostic performance of circulating miRNAs in GC diagnosis. We conducted a systematic and comprehensive approach for the inclusion of studies. The sensitivity, specificity, and diagnostic odds ratio were pooled with random effects models, and a summary of receiver operator characteristic (SROC) curves were plotted. The potential heterogeneity was assessed with Q test and I2 statistics. Subgroup analyses and meta‑regressions further investigated the sources of heterogeneity. A total of 77 studies from 48 articles were eligible for the meta‑analysis. The results revealed a sensitivity of 0.76, a specificity of 0.81, and an AUC of 0.86 for gastric cancer diagnosis with circulating miRNAs. In addition, subgroup analyses indicated that multiple miRNAs assays, non‑microarray screening approaches, and serum‑based miRNA assays exhibited good diagnostic performance in contrast to a single miRNA assay, microarray expression profiling screening, and plasma‑based miRNA group analysis. The diagnostic ability of miRNAs in early stage I‑II groups and the high expression group were approximately similar to that in the stage I‑IV groups and the low expression group. For the circulating miRNAs, our meta‑analysis identified a combination of multiple miRNAs, non‑microarray chip screening, and serum‑based miRNA assays were associated with the most effective GC diagnostic performance. However, many unclear molecular mechanisms limited the accuracy of the diagnostic results, and should be interpreted with caution. Further large‑scale prospective studies are required for validating the diagnostic applicability of circulating miRNAs in gastric cancer patients.

Numerous isomeric equilibrium structures have been identified for the Al

Chronic hepatitis B virus (HBV) infection is a major risk factor for hepatocellular carcinoma (HCC), and HBV X protein (HBx) serves an essential role in the development of HCC. However, its mechanism remains to be elucidated. The aim of the present study was to investigate the role and mechanism of the HBx protein in the epithelial-mesenchymal transition (EMT) and metastasis of HCC. The HCCLM3 cell line was transfected with a HBx-expressing vector. The effects of HBx overexpression on proliferation, migration, invasion and EMT capacities of the HCCLM3 cell line were evaluated using MTT, migration and invasion assays, and western blotting, respectively. Furthermore, the impact of High mobility group AT-hook 2 (HMGA2) knockdown on HBx-mediated metastasis was investigated in the HCC cell line HCCLM3. The results demonstrated that HBx significantly upregulated HMGA2 expression, and enhanced the proliferation, EMT, invasion and migration in HCC cells. Furthermore, HMGA2 knockdown almost abolished HBx-induced EMT and metastasis in HCC. The results of the present study suggest that HBx promotes the proliferation, EMT, invasion and migration of HCC cells by targeting HMGA2. HMGB2 may serve as a potential therapeutic target for HBV-associated HCC.

Based on the density functional theory for exchange-correlation potential, fluorocarbon molecular cages are investigated as building blocks of hyperhalogens. By utilizing C8 F7 as a ligand, a series of hyperhalogen anions, that is, M(C8 F7 )2 (-) (M=Li, Na, and K) and M(C8 F7 )3 (-) (M=Be, Mg, and Ca), are modeled. Calculations show that all the C8 F7 moieties preserve their geometric and electronic integrity in these anions. These anionic molecules possess larger vertical electron detachment energies (5.11-6.45 eV) than that of C8 F7 (-) , verifying their hyperhalogen nature. Moreover, it is also revealed that using larger fluorinated cage C10 F9 as ligands can bring about hyperhalogen anions with larger vertical electron detachment energies. The stability of these studied anions is determined by their large HOMO-LUMO gaps and positive dissociation energies of predetermined possible fragmentation pathways. It is hoped this study will provide an approach for the construction of new types of hyperhalogens and stimulate more research in superatom chemistry.

This paper presents a case study in establishing the operation space of a Grignard reaction in a continuous stirred tank reactor (CSTR). The operation space is the multivariate space with the boundary defined by the proven acceptable range of every CSTR process parameter such as flow rates and temperature. The mapping of the operation space was conducted by a thorough understanding of reaction kinetics, magnesium (Mg) sequestration efficiency, equipment characterization, and the impact of process disturbances has on steady state. A fit-for-use reaction kinetics model was developed to parametrize the kinetics and mass transfer rates of the batch Grignard reaction across different scales from 250 mL to 500 gallons. The reaction kinetics model was applied to design the Mg recharge frequency accounting operational variability to ensure a state of control can be maintained. Furthermore, reactor temperature was determined to be suitable to detect process failures to ensure process safety and product quality at ...

The creative concept of superatom brings a new dimension to the conventional periodic table, which has been gradually enriched by both theoretical and experimental research. In this article, we propose a new member, namely, Al12Be, to the superatom family. The amazing similarity between the Al12Be cluster and the chalcogen elements makes the former an excellent superatom counterpart of the latter. In addition, Al12Be exhibits more exothermic first electron affinity (EA) and less endothermic second EA values due to its size advantage over the chalcogen atoms, showing the superatom superiority in this respect. The stable compounds formed between Al12Be and other atoms, such as carbon, beryllium, calcium, and lithium, provide further evidence to support the quasi-chalcogen identity of Al12Be.

By doping an Al12N12 nanocage with superalkali Li3O, a series of Li3O@Al12N12 compounds were theoretically designed and investigated for the first time. Computational results reveal that these species contain diffuse excess electrons, and thus can be regarded as inorganic electrides of a new type. As expected, these proposed electrides possess considerable first hyperpolarizabilities (β0) up to 1.86 × 10(7) au. In particular, the lowest-energy Li3O@Al12N12 exhibits high stability and excellent deep-ultraviolet transparency. Moreover, the effects of superalkali and nanocage subunits on the NLO responses of M3O@Al12N12 (M = Li, Na, K) and Li3O@X12Y12 (X = B, Al; Y = N, P) are systemically investigated. Results show that the respective substitution of Na3O and B12P12 for Li3O and Al12N12 can bring a larger β0 for such electrides. This study may be significant in terms of providing an effective strategy to design thermally stable inorganic electrides as potential high-performance NLO molecules.

On the basis of stable alkaline earth metal ammines, a series of M(NH3)6NaCl and M(NH3)6Na2 (M = Mg and Ca) excess electron compounds were theoretically constructed and studied by using the density functional theory. The electride or alkalide characteristics of these compounds are verified by their electronic structures, HOMOs, and small VIE values. It is worth noting that the M(NH3)6Na2 alkalides have novel electronic structures that contain double alkali metal anions. As expected, all the noncentrosymmetric M(NH3)6NaCl and M(NH3)6Na2 compounds possess considerable first hyperpolarizabilities (β0) up to 123 050 au, which can be attributed to low excitation energies (ΔEs) and large oscillator strength (f0) of their crucial excited states. In addition, results reveal that the Ca(NH3)6-based species with lower ΔEs and larger transition moments (Δμ) show larger β0 values compared with the corresponding Mg(NH3)6-based ones with similar geometries. This study may be significant in terms of designing excess electron compounds of new-type, especially alkalides with multiple alkali metal anions.

Hyperhalogens are a class of highly electronegative molecules whose electron affinities even exceed those of their superhalogen ligands. Such species can serve as new oxidizing agents, biocatalysts, and building blocks of unusual salts, and hence are important to the chemical industry. Utilizing stable N5(-) as the ligand, a series of aromatic hyperhalogen anions, namely mononuclear M(N5)(k+1)(-) (M = Li, Be, B) and dinuclear M2(N5)(2k+1)(-) (M = Li, Be), have been reported here for the first time. Calculation results based on the density functional theory revealed that all the N5(-) subunits preserve their structural and electronic integrity as well as aromatic characteristics in these anions. Especially, these anionic molecules exhibit larger vertical electron detachment energies (6.76-7.86 eV) than that of the superhalogen ligand N5(-), confirming their hyperhalogen nature. The stability of these studied anions is guaranteed by their large HOMO-LUMO gaps, and positive dissociation energies of predetermined fragmentation pathways. We hope this work will not only provide evidence of a new type of hyperhalogen molecule but also stimulate more research interest and efforts in the amazing superatom realm.

Using the M06-2X density functional theory, unusual manipulative effects of spin multiplicity and excess electron number on the structure and static first hyperpolarizability (β0) are revealed for new electride molecules with multiexcess electrons. (1) For the spin effect on molecular structure, the low spin multiplicity brings bent structures (1L2 and 2L3) for linear isomers. (2) For the dramatic effect of spin multiplicity on β0, the considerable β0 of 22.7 × 104 au for the low spin structure 2L3 is larger by 21 times than that of 1.1 × 104 au for the high spin structure 4L3 due to one excess electron spin reversal. The low spin structure with doubly and singly occupied frontier orbitals is relevant to the low transition energy and complex distribution of electron density, which dramatically enhances β0. (3) For the effect of excess electron number on β0, the β0 value increases rapidly with increasing excess electron number. A long chain-shaped electride molecule (for instance, 2L3) with multiexcess ele...

SiO2-coated phosphors of Ce0.67Tb0.33MgAl11O19(CTMA) were prepared by the sol–gel method in order to enhance thermal stabilities. The phase structures, microstructures and luminescence properties were studied by the X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscope (TEM) and fluorescence spectrometer respectively. The emission intensity of SiO2-coated Ce0.67Tb0.33MgAl11O19phosphor was little lower than uncoated phosphor. After baked at 600°Cfor 6h, the coated CTMA showed good thermal stabilities. The luminance performance of SiO2-coated phosphor is 93% compared with the unbaked CTMA, which is improved 10% in contrast to uncoated.

Oxidative stress and excess hepatic lipid accumulation contribute to non-alcoholic fatty liver disease. Radix Hedysari polysaccharides (RHP) have attracted interest due to their antioxidant properties and immunomodulatory effects. However, the effect of RHP on hepatic lipid metabolism remains to be elucidated. In the present study, the response of Sprague-Dawley rat livers to a high-fat diet and RHP treatment was investigated by evaluating body weight, liver histology, hepatic lipid content, adenosine monophosphate-activated protein kinase (AMPK) activity and lipid metabolism gene transcriptional profiles. The present study demonstrated that RHP ameliorated lipid metabolism disorders, regulated hepatic lipid content, improved liver inflammation and damage, activated AMPK via phosphorylation, upregulated peroxisome proliferator-activated receptor α and downregulated the mRNA expression of sterol regulatory element binding protein-1c in rat livers, which reduced lipogenesis and increased lipolysis. Taken together, these results suggested that RHP effectively ameliorates lipid metabolism disorders in rat livers; thus, RHP may be a potential therapeutic agent in the prevention of hepatic steatosis.

A new series of polynuclear superalkali cations YLi4(+) (Y = PO4, AsO4, VO4) has been characterized using ab initio methods. The central Y(3-) (PO4(3-), AsO4(3-), VO4(3-)) acid radicals preserve their structural and electronic integrity in the first several lowest-lying isomers of YLi4(+). Meanwhile, the introduction of Li(+) cations can also dissociate an O(2-) ion from the Y(3-) groups. Besides, the AsO4(3-) group is discerned to be separated into AsO2(-) and O2(2-) fragments other than AsO3(-) and O(2-) units. This is why the AsO4Li4(+) cation has been found to possess more diverse structures. The vertical electron affinities (EAvert) of the YLi4(+) cations range from 2.44 to 4.67 eV, which are low enough to validate the superalkali or pseudoalkali identity of the title species. It is also noteworthy that the YLi4(+) conformer with Td symmetry allows a more even distribution of the excess positive charge, and consequently exhibits the lowest EAvert value of ca. 2.45 eV.

Recent developments in the field of superatom chemistry have brought forward various clusters or compounds exhibiting novel structures and special properties. By utilizing aromatic clusters as building blocks, a new class of aromatic superatom cations MLin+1+ is proposed here. Theoretical investigations reveal that most of the Mn– aromatic anions maintain their structural and electronic integrity and play the role of central core inside the MLin+1+ cations. The studied cations feature low vertical electron affinities (EAvert), large HOMO–LUMO gaps, and high thermodynamic stability with respect to loss of a Li+ ion. Besides, two kinds of MLin+1–(super)halogen compounds have been theoretically constructed and characterized, by which the feasibility of using the aromatic MLin+1+ cations as building blocks for the design of new superatom compounds is explored. The results presented in this work appear to show the existence of aromatic, and particularly organic, superatoms and may assist with further systemati...

The effects of substituents on the structure, character, and nonlinear optical (NLO) properties of the organic alkalide Li(+) (calix[4]pyrrole)Li(-) were studied by density functional theory. Natural bond orbital analysis and vertical ionization energies reveal that electron-donating substituents strengthen the alkalide character of Li(+) (calix[4]pyrrole)Li(-) and that they are beneficial for a larger first hyperpolarizability (β(0) ) value. However, electron-withdrawing substituents have the opposite effect. The dependence of the NLO properties on the number of substituents and their relative position was detected in multisubstituted Li(+) (calix[4]pyrrole)Li(-) compounds. For both the amino- and methyl-substituted derivatives, the polarizabilities and the first hyperpolarizabilities increase as more pyrrole β-H atoms are substituted. Moreover, distribution of the substituents so that they are as far away from each other as possible resulted in an increase in the β(0) value. The new knowledge obtained in this study may provide an effective approach to enhance the NLO responses of alkalides by employing pyrrole derivatives as complexants.

High-sensitivity detection of trace amounts of c-erbB-2 oncogene was reported to be equal to or surpass the ability of CA 15-3 for early diagnosis and/or follow-up recurrent screening of breast cancer. Therefore, in the current study, by using upconversion nanoparticles (UCNPs), rare earth-doped NaYF4:Yb3+/Er3+ as the luminescent labels, a upconversion luminescent (UCL) biosensor based on dual-signal amplification of exonuclease III (ExoIII)-assisted target cycles and long-range self-assembly DNA concatamers was developed for the detection of c-erbB-2 oncogene. The proposed biosensor exhibited ultrasensitive detection with limit as low as 40 aM, which may express the potential of being used in trace analysis of c-erbB-2 oncogene and early diagnosis of breast cancer.

Digital instrument transformer calibrator is the key equipment which is applied to calibrate instrument transformers automatically. The instrument transformer based on principle of high potential difference measurement is suitable for calibration of voltage instrument transformer with high voltage and high accuracy, as it avoids being affected by additive error. This paper presents a plan for high precise instrument transformer calibrator based on principle of high potential difference measurement. On the basis of this design scheme, the technology of shielded input-signal wire, input-signal isolated amplification and shielded circuit is adopted to design the instrument transformer calibrator. The produced calibrator is able to fulfill the requirement of self-calibration of power voltage ratio standard due to its excellent performance with high accuracy and stability.

The principle of quasi-synchronous discrete fourier transform (DFT) algorithm was introduced and the simulation on the algorithm was carried out. The quasi-synchronous DFT algorithm is independent of the first sample point and it is able to start sampling at any moment. The maximum relative amplitude error and phase error of the algorithm are 0.05 % and 5.4° when the frequency of the signal is between 49.5 Hz and 50.5 Hz. The accuracy of quasi-synchronous DFT algorithm can be improved by scores of times than that of DFT algorithm.

Recently, China is developing smart grid with great strength, more and more digital substations will be built, therefore, it is time for thinking of the accuracy of the new electric energy metering devices. But the new electric energy metering devices are different from the traditional meters by using Digi-Data interface instead of voltage and current interface, requiring a new method of testing error. By equivalently transforming electric power from analog to digital, we design a special electric power standard with digital-data-interface according to IEC61850. Based on the special electric power standard, this article introduces a new method for calibrating digi-data input power meter.

This paper puts forward a dielectric barrier discharge detection system using PMT for photoelectric element. According to faint light signal characteristics and testing purpose of dielectric barrier discharge, this system is designed, including three parts: optical fiber transmission, photoelectric conversion and signal processing circuit. This paper introduces design and ideas of the system framework and presents circuit design parameter. Results in atmospheric pressure of dielectric barrier discharge detection experiment show that the system has high sensitivity, fast response, can effectively distinguish discharge and interference signals, gather more signals in different areas.

Introduces the analog phase compensation technology used in electronic instrument transformer, put forward a method of digital phase compensation in electronic transformer and carries out in the 220KV electronic instrument transformer measurement system, the resolution ratio of the phase compensation is 1 second and the maximum range of the phase compensation is 270 second, which can meet the phase adjustment of electronic instrument transformer; compares the analog compensation technology and digital phase compensation technology, analyzes their characteristics and different applications.

A fully continuous process including an asymmetric hydrogenation reaction operating at 70 bar hydrogen, aqueous extraction, and crystallization was designed, developed, and demonstrated at pilot scale. This paper highlights safety, quality, and throughput advantages of the continuous reaction and separations unit operations. Production of 144 kg of product was accomplished in laboratory fume hoods and a laboratory hydrogenation bunker over two continuous campaigns. Maximum continuous flow vessel size in the lab hoods was 22 L glassware, and maximum plug flow tube reactor (PFR) size in the bunker was 73 L. The main safety advantages of running the hydrogenation reaction continuous rather than batch were that the flow reactor was smaller for the same throughput and, more importantly, the tubular hydrogenation reactor ran 95% liquid filled at steady state. Therefore, the amount of hydrogen in the reactor at any one time was less than that of batch. A two-stage mixed suspension–mixed product removal (MSMPR) c...

The [3,3] Claisen rearrangement is a well-known reaction that has been very useful for the synthesis of o-allyl phenols. The thermally induced rearrangement could present safety and operational issues at large batch scale. Herein, we report a process that utilized a tube reactor to make 80 g of an early phase intermediate in a short time while mitigating the potential chemistry hazards. Thus, both project material demands and flow chemistry proof of concept were achieved.

Considering the situation with both unknown multi-parameters and uncertain multi- functions, a robust adaptive controller was constructed to solve the tracking problem of a general class of chaotic systems. What is worthy pointing out is that the uncertainties are assumed to be bounded with triangular functions which is meaningful in engineering application.

It is unavoidable to deal with the quark and gluon momentum and angular momentum contributions to the nucleon momentum and spin in the study of nucleon internal structure. However, we never have the quark and gluon momentum, orbital angular momentum and gluon spin operators which satisfy both the gauge invariance and the canonical momentum and angular momentum commutation relations. The conflicts between the gauge invariance and canonical quantization requirement of these operators are discussed. A new set of quark and gluon momentum, orbital angular momentum and spin operators, which satisfy both the gauge invariance and canonical momentum and angular momentum commutation relations, are proposed. The key point to achieve such a proper decomposition is to separate the gauge field into, the pure gauge and the gauge covariant parts. The same conflicts also exist in QED and quantum mechanics and have been solved in the same manner. The impacts of this new decomposition to the nucleon internal structure are discussed.

We studied thermal tolerance limits, heat-hardening, and Hsp70 to elucidate the difference in thermotolerance between two color variants of the sea cucumber Apostichopus japonicus. Green and Red variants occupy different habitats and have different aestivation responses to high temperature in summer. In the absence of heat-hardening, the variants showed no difference in the temperature at which 50% of the individuals died: Green, 31.49 degrees C; Red, 31.39 degrees C. However, Green specimens acquired higher thermotolerance than Red after a prior sublethal heat exposure. After 72 h of recovery from a heat-hardening treatment (30 degrees C for 2 h), the survival of Green variants was more than 50% and that of Red was less than 5% when they were treated at 33 degrees C for 2 h. Levels of mRNA and protein for Hsp70 were significantly higher in Green than Red after the heat shock of 30 degrees C, and the stability of hsp70 mRNA of Green was significantly higher than that of Red. Our findings suggest that within the same species, different variants that have similar thermal limits in the absence of heat-hardening can acquire different thermotolerances after a prior sublethal heat shock. The difference in induced thermotolerance between Green and Red is closely related to the expression pattern of Hsp70, which was partly governed by the stability of hsp70 mRNA.