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The C-C bond lengths of the linear magnetic neutral CnSb, CnSb+ cations and CnSb− anions are within 1.255–1.336 Å, which is typical for cumulene structures with moderately strong double-bonds. In this report, we found that the adiabatic ionization energy (IE) of CnSb decreased with n. When comparing the IE~n relationship of CnSb with that of pure Cn, we found that the latter exhibited a stair-step pattern (n ≥ 6), but the IE~n relationship of CnSb chains took the shape of a flat curve. The IEs of CnSb were lower than those of corresponding pure carbon chains. Different from pure carbon chains, the adiabatic electron affinity of CnSb does not exhibit a parity effect. There is an even-odd alternation for the incremental binding energies of the open chain CnSb (for n = 1–16) and CnSb+ (n = 1–10, when n > 10, the incremental binding energies of odd (n) chain of CnSb+ are larger than adjacent clusters). The difference in the incremental binding energies between the even and odd chains of both CnSb and pure Cn diminishes with the increase in n. The incremental binding energies for CnSb− anions do not exhibit a parity effect. For carbon chain clusters, the most favorable binding site of atomic antimony is the terminal carbon of the carbon cluster because the terminal carbon with a large spin density bonds in an unsaturated way. The C-Sb bond is a double bond with Wiberg bond index (WBI) between 1.41 and 2.13, which is obviously stronger for a carbon chain cluster with odd-number carbon atoms. The WBI of all C-C bonds was determined to be between 1.63 and 2.01, indicating the cumulene character of the carbon chain. Generally, the alteration of WBI and, in particular, the carbon chain cluster is consistent with the bond length alteration. However, the shorter C-C distance did not indicate a larger WBI. Rather than relying on the empirical comparison of bond distance, the WBI is a meaningful quantitative indicator for predicting the bonding strength in the carbon chain.

Cisplatin-based platinum compounds are important clinical chemotherapeutic agents that participate in most tumor chemotherapy regimens. Through density-functional theory calculations, the formation and stability of the inorganic oxide carrier, the mechanisms of the hydrolysis reaction of the activated platinum compound, and its binding mechanism with DNA bases can be studied. The higher the oxidation state of Pt (II to IV), the more electrons transfer from the magnesia–gold composite material to the platinum compound. After adsorption on the composite carrier, 5d←2p coordination bonds of Pt-N are strengthened. For flat and oblique adsorption modes of cisplatin, there is no significant difference in the density of states of the gold and magnesium oxide film, indicating the maintenance of the heterojunction structural framework. However, there are significant changes in the electronic states of cisplatin itself with different adsorption configurations. In the flat configuration, the band gap width of cisplatin is larger than that of the oblique configuration. The Cl-Pt bond range in the Pt(III) compound shows a clear charge reduction on the magnesia film, indicating the Cl-Pt bond is an active site with the potential for decomposition and hydrolysis. The substitution of chloride ions by water can lead to hydrolysis products, enhancing the polarization of the composite and showing strong charge separation. The hydrolysis of the free platinum compound is endothermic by 0.309 eV, exceeding the small activation energy barrier of 0.399 eV, indicating that hydrolysis of this platinum compound is easily achievable. ADME (absorption, distribution, metabolism, and excretion) prediction parameters indicate that hydrolysis products have good ESOL (Estimated SOLubility) solubility and high gastrointestinal absorption, consistent with Lipinski’s rule. During the coordination reaction process, there are significant changes in the distribution of frontier molecular orbitals, with the HOMO (highest occupied molecular orbital) of the initial state primarily located on the purine base, providing the possibility for electron transfer to the empty orbitals of the platinum compound in the LUMO (lowest unoccupied molecular orbital). The HOMO and HOMO-1 of the transition state and product are mainly distributed on the platinum compound, indicating clear electron transfer and orbital rearrangement. The activation energy barrier for the purine coordination reaction with the hydrolysis products is reduced to 0.61 eV, and the dipole moment gradually decreases to 6.77 Debye during the reaction, indicating a reduction in the system’s charge separation and polarization. This contribution is anticipated to provide a new theoretical clue for developing inorganic oxide carriers of platinum compounds.

A fluorescence turn-on assay for alkaline phosphatase (ALP) activity is developed through the controlled release of polyethyleneimine-capped copper nanoclusters (PEI-capped CuNCs) from the MnO 2 nanosheets. In an aqueous solution, the positively charged PEI-capped CuNCs could be adsorbed onto the surface of the negatively charged MnO 2 nanosheets. Such adsorption through favorable electrostatic interactions could efficiently quench the nanocluster fluorescence emission via resonance energy transfer from the PEI-capped CuNCs to the MnO 2 nanosheets. 2-Phospho- l -ascorbic acid (AAP) could be hydrolyzed to l -ascorbic acid (AA) in the presence of ALP. AA could reduce MnO 2 into Mn 2+ and trigger the disintegration of the MnO 2 nanosheets. As a result, the CuNCs were released and the quenched fluorescence was recovered efficiently. The detection strategy is simple, inexpensive, sensitive, selective, with low toxicity, and has better biocompatibility. The newly fabricated biosensor for ALP activity will potentially make it a robust candidate for numerous biological and biomedical applications.

A new water soluble fluorescent coronene probe (CTCA) was synthesized and is shown to display strong fluorescence (with excitation/emission maxima at 313/450 nm) in aqueous solution. Dopamine was oxidized under air to form polydopamine (PDA) which quenches the fluorescence of CTCA. The enzyme acetylcholinesterase (AChE) is known catalyze the hydrolysis of acetylthiocholine to produce thiocholine. Thiocholine inhibits the polymerization of DA, and this leads to recovery in CTCA fluorescence. These findings form the basis for a new method for detection of AChE activity. The assay has a detection limit as low as 0.05 mU·mL −1 of AChE. It is highly selective, and other enzymes do no noticeably interfere. It was applied to the determination of AChE activity in (spiked) human serum, and of AChE inhibitors in (spiked) lake water samples. Graphical abstract Controlled synthesis of polydopamine for the highly sensitive and selective sensing of AChE activity is reported for the first time.

A fluorescence turn-on assay for alkaline phosphatase (ALP) activity is developed through the controlled release of polyethyleneimine-capped copper nanoclusters (PEI-capped CuNCs) from the MnO.sub.2 nanosheets. In an aqueous solution, the positively charged PEI-capped CuNCs could be adsorbed onto the surface of the negatively charged MnO.sub.2 nanosheets. Such adsorption through favorable electrostatic interactions could efficiently quench the nanocluster fluorescence emission via resonance energy transfer from the PEI-capped CuNCs to the MnO.sub.2 nanosheets. 2-Phospho-l-ascorbic acid (AAP) could be hydrolyzed to l-ascorbic acid (AA) in the presence of ALP. AA could reduce MnO.sub.2 into Mn.sup.2+ and trigger the disintegration of the MnO.sub.2 nanosheets. As a result, the CuNCs were released and the quenched fluorescence was recovered efficiently. The detection strategy is simple, inexpensive, sensitive, selective, with low toxicity, and has better biocompatibility. The newly fabricated biosensor for ALP activity will potentially make it a robust candidate for numerous biological and biomedical applications.

A fluorescence turn-on assay for alkaline phosphatase (ALP) activity is developed through the controlled release of polyethyleneimine-capped copper nanoclusters (PEI-capped CuNCs) from the MnO nanosheets. In an aqueous solution, the positively charged PEI-capped CuNCs could be adsorbed onto the surface of the negatively charged MnO nanosheets. Such adsorption through favorable electrostatic interactions could efficiently quench the nanocluster fluorescence emission via resonance energy transfer from the PEI-capped CuNCs to the MnO nanosheets. 2-Phospho-L-ascorbic acid (AAP) could be hydrolyzed to L-ascorbic acid (AA) in the presence of ALP. AA could reduce MnO into Mn and trigger the disintegration of the MnO nanosheets. As a result, the CuNCs were released and the quenched fluorescence was recovered efficiently. The detection strategy is simple, inexpensive, sensitive, selective, with low toxicity, and has better biocompatibility. The newly fabricated biosensor for ALP activity will potentially make it a robust candidate for numerous biological and biomedical applications.

With the widespread application of the Internet of Things (IoT), ensuring communication security for IoT devices is of considerable importance. Since IoT data are vulnerable to eavesdropping, tampering, forgery, and other attacks during an open network transmission, the integrity and authenticity of data are fundamental security requirements in the IoT. A certificateless signature (CLS) is a viable solution for providing data integrity, data authenticity, and identity identification in resource-constrained IoT devices. Therefore, designing a secure and efficient CLS scheme for IoT environments has become one of the main objectives of IoT security research. However, the existing CLS schemes rarely focus on strong unforgeability and replay attacks. Herein, we design a novel CLS scheme to protect the integrity and authenticity of IoT data. In addition to satisfying the strong unforgeability requirement, the proposed scheme also resists public key replacement attacks, malicious-but-passive key-generation-centre attacks, and replay attacks. Compared with other related CLS schemes without random oracles, our CLS scheme has a shorter private key, stronger security, and lower communication and computational costs.

The existing proxy re-signature schemes have drawbacks in terms of privacy protection and signature efficiency. Our scheme is based on the proxy re-signature scheme, which combines the main idea of short blind signature and proposes the definition of short blind proxy re-signature scheme. Then, using the signature framework of the random oracle model, we propose a short blind proxy re-signature scheme based on the random oracle model, and prove the security of the scheme under the adaptive chosen-message attacks. The analysis shows that compared with the existing similar schemes, our scheme does not add additional verification information under the premise of shortening the signature length, and the applicability is better in the interactive transmission of devices with limited calculation and transmission performance.

Strong designated verifier signature can provide an efficient way to protect the identity privacy of the signer and the integrity of the data transmitted over the public channel. These characteristics make it very useful in outsourcing computing, electronic voting, electronic bidding, electronic auction and other fields. However, most strong designated verifier signature schemes are unable to identify the real signature generator when the signer and the designated verifier dispute a signature. In addition, the existing strong designated verifier signature schemes in the standard model rarely satisfy strong unforgeability, and thus cannot prevent the attacker from forging a valid signature on any previously signed message. Therefore, designing a strong designated verifier signature scheme without random oracles that satisfies strong unforgeability and undeniability is very attractive in both practice and theory. Motivated by these concerns, we design the first undeniable strong designated verifier signature scheme without random oracles, in which the arbiter can independently perform the judgment procedure to prove whether a controversial signature is generated by the signer or the designated verifier. Under standard assumptions, the scheme is proved to be strongly unforgeable in standard model. Furthermore, it not only achieves non-transferability and privacy of the signer’s identity but also satisfies the undeniable property of traditional digital signature schemes. Performance analysis results show that the length of the signer’s private key, the designated verifier’s private key and signature length are 40 bits, 40 bits and 384 bits, respectively. Compared with he related schemes, the proposed scheme has higher performance in signature length, private key size and computational overhead. Finally, we show how to apply it to implement outsourcing computation in cloud computing.