Pricing Parisian down-and-in options

In this paper, we price American-style Parisian down-and-in call options under the Black–Scholes framework. Usually, pricing an American-style option is much more difficult than pricing its European-style counterpart because of the appearance of the optimal exercise boundary in the former. Fortunately, the optimal exercise boundary associated with an American-style Parisian knock-in option only appears implicitly in its pricing partial differential equation (PDE) systems, instead of explicitly as in the case of an American-style Parisian knock-out option. We also recognize that the “moving window” technique developed by Zhu and Chen (2013) for pricing European-style Parisian up-and-out call options can be adopted to price American-style Parisian knock-in options as well. In particular, we obtain a simple analytical solution for American-style Parisian down-and-in call options and our new formula is written in terms of four double integrals, which can be easily computed numerically.     

Ultrasound responsive block copolymer micelle of poly(ethylene glycol)–poly(propylene glycol) obtained through click reaction

The well-defined amphiphilic poly(ethylene glycol)-block-poly(propylene glycol) copolymer containing 1, 2, 3-triazole moiety and multiple ester bonds (PEG-click-PPG) was prepared by click reaction strategy. The PEG-click-PPG copolymer can self-assemble into spherical micelles in aqueous solution. It is found that high intensity focused ultrasound (HIFU) can open the copolymer PEG-click-PPG micelles and trigger the release of the payload in the micelle. The multiple ester bonds introduced in the junction point of the copolymer chain through click reactions were cleaved under HIFU, and leads to the disruption of the copolymer micelle and fast release of loaded cargo. The click reaction provides a convenient way to construct ultrasound responsive copolymer micelles with weak bonds.     

Systematic characterization of adenosine triphosphate response to lung cancer epidermal growth factor receptor missense mutations: A molecular insight into “generic” drug resistance mutations

Many missense mutations in human epidermal growth factor receptor (EGFR) are clinically involved in lung cancer and may cause acquired resistance to tyrosine kinase inhibitors. Traditionally, the resistance is considered to be established by impairing inhibitor affinity due to the mutations. However, it was found that, instead of blocking inhibitor binding, the gatekeeper mutation T790M can improve the kinase affinity for its natural substrate adenosine triphosphate (ATP), which is thus regarded as a “generic” resistance mutation that will reduce the potency of any ATP-competitive reversible kinase inhibitor. In this study, we attempt to systematically investigate the binding behavior of ATP to clinically observed EGFR missense mutants in nonsmall-cell lung cancer to identify those substantial mutations that may significantly increase (or decrease) ATP affinity. Several substantial mutations are excluded because they are also involved in kinase's catalytic activity or directly influence inhibitor binding, thus largely complicating the multiple dependent relationships of kinase, ATP, and inhibitor. Two new “generic” resistance mutations, A839T and E758G, are identified, which can improve ATP affinity by forming a favorable hydrogen bond and by eliminating unfavorable electrostatic effect between the kinase and ATP, respectively.     

Mild and Efficient Synthesis of Carboxylic Acid Anhydrides from Carboxylic Acids and Triazine Coupling Reagents

Abstract

Anhydrides of carboxylic acids were obtained in 53%–95% yield by treatment of appropriate carboxylic acids with 2‐chloro‐4,6‐dimethoxy‐1,3,5‐triazine (CDMT) or 2,4‐dichloro‐6‐methoxy‐1,3,5‐triazine (DCMT) in the presence of N‐methylmorpholine. It has been proved that synthesis proceeds via triazine active esters 3a,b, which are able to acylate carboxylate anion but not less nucleophilic carboxylic acid.     

Prospective of the LDI MS to characterization the corrosion products of silver-copper alloys on an example of the Ag-Cu-X (X- Zn,Pd, In) system

This work presents the perspective of applying the laser desorption/ionization mass spectrometry (LDI MS) for characterization the anode film of the Ag₆₀Cu₂₆Zn₁₄, Ag_58.5Cu_31.5Pd₁₀, and Ag₆₃Cu₂₇In₁₀ alloys (at high concentrations of chloride ions in solutions). The reference LDI mass spectra of anode films of pure Ag and Cu have been used for the identification of product corrosion. Knowing the clusters detected in the reference spectra lead to the facilitating identification of the LDI mass spectrum of the sample and reduces the analysis time. The LDI MS analysis of these alloys revealed that the predominant corrosion product are AgCl (from Ag_nCl_n+1^?/+, n = 1–3), and CuCl (from “superhalogen” Cu_mCl_n^? clusters, m = 1–2, n = 2–6); it also revealed Cu₂(OH)₃Cl (from Cu₂(OH)(H₂O)₂⁺) and Cu₂O (from Cu(H₂O)⁺, Cu₂O doped with chlorine). These results are in accordance with the X-ray diffraction and Raman analysis. The LDI MS spectra of alloys contain the additional peaks formed due to the mutual influences of different metals in the alloys (AgCuCl₃^? (AgCl-CuCl₂^?), AgCu₂Cl₄^? (AgCl-CuCl-CuCl₂^?), and Ag₂CuCl₄^? (AgCl-AgCl-CuCl^?), which is consistent with the identified corrosion products. It should be noted that the LDI MS suggest the presence of CuCl₂, which can be interpreted as the corrosion products retained in the porous films of alloys, and not detected by the other methods due to a small amount. The future theoretical and experimental studies of metal clusters, significant for metallurgy, can contribute that the LDI MS is becoming a powerful analytical tool for characterization the metal surfaces.     

Complementary Design in Multicomponent Electrocatalysts for Electrochemical Nitrogen Reduction: Beyond the Leverage in Activity and Selectivity

Electrochemical nitrogen reduction reaction (eNRR) is promising in place of the Haber–Bosch process for artificial N₂ fixation. However, the high activity and selectivity of eNRR are challenging to achieve simultaneously due to the scaling relations. Such “leverage” between activity and selectivity has severely restricted eNRR. To overcome this bottleneck, the complementary design of electronic structures in multicomponent electrocatalysts has been recently pursued, aiming to maximize the advantages of each component and optimize the multistep reactions, which has stood at the cutting edge in this aspect. Here, we present a minireview of the design, performance, and mechanism of multicomponent electrocatalysts with complementary electronic structures. We particularly emphasize the interactions between N₂ and elements from d-, p-, and s-blocks, which are essential for understanding how these electrocatalysts are beyond the “leverage” between activity and selectivity.     

Di-functional magnetic nanoflowers: A highly efficient support for immobilizing penicillin G acylase

The novel di-functional magnetic nanoflowers (DMNF) which had both epoxy groups and hydrophilic catechol as well as phthaloquinone groups capable of covalently coupling of penicillin G acylase (PGA) were characterized by scanning electron microscopy, transmission electron microscope (TEM), vibrating sample magnetometer, N₂ adsorption, and so on. The studies showed that DMNF possessed “hierarchical petal” structure of nanosheets had specific saturation magnetization of 39.7 emu/g and average pore diameter of 25.4 nm as well as specific surface area of 17.28 m²/g. For hydrolysis of penicillin G potassium catalyzed by the PGA immobilized on DMNF with enzyme loading of 106 mg/g-support, its apparent activity reached 2,667 U/g, which benefited from the “hierarchical petal” and large pore structure of the magnetic DMNF leading to high enzyme loading and fast diffusion of substrate molecules to the immobilized PGA to reaction. The apparent activity of the immobilized PGA could keep 2,408 U/g (above 90% of its initial activity) after repeating use for 10 cycles. The magnetic immobilized PGA exhibited excellent operational stability due to covalently coupling of the enzyme molecules between the support by covalent interaction of the amino groups of PGA and the reactive groups of epoxy, catechol, and phthaloquinone groups on DMNF. Furthermore, the PGA displayed good acid and alkaline resistance as well as thermal stability by immobilization using DMNF.     

A Heterometallic MOF based on Monofunctional Linker by “One-pot” Solvothermal Method for Highly Selective Gas Adsorption

Heterometallic MOFs, as an important branch of MOF materials, open up a new way to design and synthesize innovative MOF materials. Hence, it has positive significance for the development of MOF materials. By utilizing monofunctional linker CBDA [5,5'-(carbonylbis(azanediyl))-diisophthalic acid], a heterometallic MOF In/Gd-CBDA was obtained under “one-pot“ solvothermal method. The three-dimensional framework exhibits (3,4,6)-connected network belonging to a new topology. In addition, the synthetic conditions that affect the growth of crystal have been studied in detail. Numerous experiments led to the finding that the type and composition of solvents are very important for inducing the recognition of carboxylic acid groups at different positions coordination to diverse metals. Furthermore, the mechanism of this kind of heterometallic MOFs assembled by monofunctional linker under “one-pot” solvothermal method has been clarified, which is mainly related to the steric hindrance of functional groups and the properties of heterometals. Based on ideal adsorbed solution theory (IAST), In/Gd-CBDA shows the efficient selective gas adsorption, especially for equimolar mixtures of CO₂/CH₄ (13) and C₃H₈/CH₄ (321). This work of heterometallic MOF material assembled by monofunctional linker under “one-pot” solvothermal method provides a new platform for the development of MOF materials in terms of enriching the topological family and broadening possibilities in advanced applications.