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Amino‐single benzene‐based fluorophores (SBBFs) are representative small‐size fluorescent dyes that have an electron push‐pull structure within the benzene core. In this work, a new library of amino‐SBBFs, which have trifluoroacetyl moiety at the electron‐pushing amine group (named SBBF‐TFA), featuring a variety of methylamines, dimethylamines, as well as acetyl. To explore the SBBF‐TFA library, we conducted (i) library synthesis, (ii) assessment of various photophysical properties in nine different types of organic/aqueous solvents, and (iii) evaluation of cytotoxicity in the HeLa cell line. We believe that our findings provide valuable insights for advancing novel small‐molecule fluorescent probes and materials with diverse applications across pharmacochemical fields. [ABSTRACT FROM AUTHOR]

VX is one of the chemical warfare agents that attack victims' nervous systems and ultimately lead to their death. Upon VX exposure, circulating proteins in the bloodstream can be modified with VX that may produce diagnostic VX adducts. Thus, these adducts would be key evidence for the forensic investigation against chemical warfare or terrorism. In this study, we discovered a list of potential blood protein biomarkers for VX exposure. To do so, we employed high‐resolution mass spectrometry‐based proteomics and identified 18 VX‐adducted proteins with 32 adduct sites from VX‐treated human plasma samples. Furthermore, we examined these targets using a data‐independent acquisition method and obtained eight practically detectable biomarkers. Our results may serve as a valuable resource for verifying nerve agent exposure under chemical attack. [ABSTRACT FROM AUTHOR]

Zr‐based metal–organic frameworks (MOFs) were modified with pendant tetrazole ligands for proton conductivity studies. Although tetrazolate ligands coordinated to metal cations have been widely utilized to construct MOFs or porous coordination polymers, to date, the use of uncoordinated tetrazole groups in MOFs has been limited. In this study, a benzene‐1,4‐dicarboxylic acid with pendant tetrazole groups (BDC‐N4) was synthesized and used to prepare a Zr‐based UiO‐66 MOF using a mixed‐ligand strategy. The tetrazole‐functionalized UiO‐66‐N4 was compared to MOFs containing other acidic functional groups (hydroxyl, carboxylic acid, and sulfonic acid) with respect to their proton conductivities and acidities (calculated pKa). Interestingly, UiO‐66‐N4 showed a significant decrease in the activation energy with increase in the amount of added tetrazole groups, suggesting the Grotthuss proton conduction mechanism for uncoordinated tetrazole‐containing MOFs. [ABSTRACT FROM AUTHOR]

We investigated the off‐target binding of amyloid‐beta (Aβ) target [18F]florapronol ([18F]FC119S) using postmortem Alzheimer's disease (AD) brain tissue, compared with a known Aβ target imaging agent, [125I]TZDM and tau targeting [125I]MK as positive and negative controls, respectively. Off‐target binding of monoamine oxidase‐A and ‐B (MAO‐A and ‐B) was screened for FC119S and Pittsburgh compound B (PiB). Autoradiography (ARG) was performed to screen the Aβ‐binding potential using human AD postmortem brain tissue sections. Colocalization was quantitatively analyzed by using image analysis software. Pathological analysis was performed for screening of specific binding of amyloid‐beta and phospho‐tau. Amyloid‐beta targeting [18F]FC119S and [125I]TZDM tracers were showed a similar binding pattern in ARG, but [125I]MK was showed a different binding patterns. In the blocking experiment, [18F]FC119S binding was effectively blocked by a cold TZDM compound. FC119S and PiB were not showed specific binding with MAO‐A and MAO‐B. The autoradiographic binding pattern was positively correlated with the Aβ expression. [ABSTRACT FROM AUTHOR]

We provide a simple and systematic computational model to study ion channel permeability using density functional theory. While existing permeability models with a hard‐wall steric hindrance factor work reasonably well for large ions, they severely inhibit the permeation of small ions through channel pores. Here, by introducing a steric hindrance factor that allows pore expansion due to intrinsically soft ion transfer channel walls, the new permeability model accurately describes the effect of steric hindrance stemming from the soft and flexible ion channel wall. Most importantly, the soft‐wall ion transfer channel model works for a wide range of ionic radii from fluoride to gluconate. In addition, we show that strong local electrostatic interaction between densely charged ions such as fluoride and bicarbonate and ion channels with ion binding sites significantly promotes the permeation processes. [ABSTRACT FROM AUTHOR]

Organophosphate (OP) compounds exhibit neurotoxicity by binding to serine residues of acetylcholinesterase (AChE) in the cholinergic nervous system and subsequently lead to the accumulation of acetylcholine in neuromuscular junctions of synapses. AChE capable of hydrolyzing choline esters is known to be inhibited in patients with nerve agents poisoning. Since OP is known to be transported by covalent bonding to human serum albumin (HSA), OP‐HSA adducts are considered potential diagnostic markers for OP exposures. In this study, HSA modification sites by OP or OP‐like compounds such as V‐type (VX) and Novichok‐type (A234), insecticide (DFP), and serine protease inhibitor (PMSF) were studied using liquid chromatography‐high‐resolution tandem mass spectrometry. As a result, we have discovered a novel OP‐HSA modification site, Y341. [ABSTRACT FROM AUTHOR]

Lansoprazole (LSP)‐loaded cochleates were developed using dimyristoyl phosphatidylcholine (DMPC) and cholesterol in the presence or absence of dicetyl phosphate (DCP). Cochleates containing DCP exhibited unique cylindrical morphologies, resulting in improved LSP loading and enhanced stability in an acidic environment. Thus, we suggest that the use of negatively charged components, such as DCP, is needed to formulate cochleates using a neutrally charged lipid such as DMPC. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs), which are porous inorganic–organic hybrid materials, act as versatile catalyst platforms for various organic transformations. In particular, the aerobic oxidation of alcohols to the corresponding aldehydes (or ketones) has been extensively studied using various MOFs and their analogs. In this account, we summarize the performance of MOF‐based catalysts for the aerobic oxidation of alcohols based on the position of the catalytic species and the type of functionalization. Moreover, recent advances in MOF‐based catalysts for aerobic oxidation are discussed in terms of catalytic efficiency and substrate size discrimination. [ABSTRACT FROM AUTHOR]

Herein, to elucidate the effect of substituent electronic properties on the photophysical properties of indium‐based organometallic luminophores, we prepare a series of indium complexes (1–5) with salen ligands bridged by an electron‐withdrawing 4,5‐dichlorophenylene (Cl2Ph) unit. The structures of all the complexes are fully confirmed by 1H and 13C NMR spectroscopy as well as elemental analysis. In particular, the molecular structure of 3, confirmed by X‐ray crystallography, is monomeric and the central indium atom adopts a square‐pyramidal geometry. The UV/Vis and fluorescence spectra of 1–5 show typically salen‐centered intramolecular charge transfer transitions with gradual bathochromic shifts as the electron‐donating ability of the substituents increases. This feature is further supported by electrochimical studies. Furthermore, the lowest unoccupied molecular orbital energy levels of 1–5 are considerably lower (approximately −3.70 eV) than those of salen‐based indium complexes with other aryl‐bridging units owing to the reduced electron‐donating effect of the (Cl2Ph)salen group. [ABSTRACT FROM AUTHOR]

The synthesis of amine skeletons and catalytic bond formation in aliphatic amines are important synthetic methodologies. Although various metal‐catalyzed organic transformations have been successfully used to functionalize and construct amine molecules, there are still many hurdles toward practical application. Moreover, site‐selectivity is generally achieved using a traditional directing group (DG) strategy, which requires at least two additional steps for the installation and removal of the DGs. Recently, a transient directing group (TDG) strategy, also known as traceless DG and temporary DG, has been widely studied for a range of selective transition metal‐catalyzed C─H bond functionalization. In this account, we have focused on the recent developments of the TDG strategy toward the site‐selective C─H bond functionalization of aliphatic amines. The design of the TDGs used for the target reaction and their critical roles in the reaction mechanism will be covered along with their selectivity and synthetic utility. [ABSTRACT FROM AUTHOR]

Lubiprostone (LPT), a novel laxative, is commercially available as a soft gelatin capsule with oily ingredient, complementing its poor water‐solubility and oxygen‐labile property. In the present study, in order to address drawbacks associated with soft capsule formulations such as difficulty in process control or high production costs, conversion of the drug‐loaded oil solution into powder dosage form was attempted using several oily ingredients and porous solid carriers. Drug solubilization in medium chain triglycerides (MCT) drastically improved the drug stability compared to that in powder or other oily ingredients, exhibiting over 95% of the drug remaining after 5 days of storage at 60 °C. However, conversion of drug‐loaded MCT into a free‐flowing powder using porous carriers markedly deteriorated drug stability. Although the drug stability in the solidified formulations prepared using Avicel PH 102 or Aerosil 200 were relatively higher than those prepared using metallic adsorbents (Florite, DCP A/T, and Neusilin US2), they were less stable than in the intact oil solution under stress and accelerated condition. This implied that the decreased thickness of the oily barrier in the solidified formula failed to inhibit the exposure of the labile compound to oxygen and/or moisture, thereby accelerating drug degradation. In vitro drug release from the adsorbent progressed rapidly, providing complete drug release within 15 min, under sink condition. This study suggests that the kind of oily vehicle and the thickness of the barrier are important factors for ensuring the stability of LPT, an oxygen‐labile compound, and additional pharmaceutical approaches are required for the construction of stable solid preparations. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (NIBs) are promising alternatives to lithium‐ion batteries for large‐scale energy applications such as energy storage systems, owing to the earth‐abundance and low cost of sodium resources. Among layered oxide cathode materials for NIBs, O3‐type NaCrO2 has attracted considerable attention owing to its electrochemically active Cr3+/4+, which is unlike that of LiCrO2, and potential for carbon coating with a high thermal stability. In this study, we propose a new facile and eco‐friendly method for applying nitrogen‐doped carbon to NaCrO2 using coffee waste as a carbon source. The synthesized O3‐type NaCrO2/coffee waste–derived N‐doped carbon composite exhibits an outstanding electrochemical performance as an NIB cathode material. The sodium/composite cell achieved a 73.7% capacity retention after 500 charge/discharge cycles and an approximate 50% discharge capacity during 43 s of charge. The results demonstrate the potential use of coffee waste for battery materials with improved electrochemical performances. [ABSTRACT FROM AUTHOR]

Eukaryotic expression systems are used widely and have the advantages of protein processing, proteolytic cleavage, disulfide bond formation, and posttranslational modification in contrast to the prokaryotic expression system. In the present study, peptide gene (olive flounder beta‐defensin or hepcidin) was inserted into the vector of pPIC9K, which involved the secretion signal and promoter AOX1. The colonies with high copy numbers of the target gene for high‐level expression were selected by G418. Approximately 30 mg/L for beta‐defensin and 25 mg/L for hepcidin was obtained from the culture medium supernatant. An ammonium sulfate salting‐out method was used for purification; this one‐step purification simplified the procedures, and the purification effect was good in terms of the purity and yield. The proteins from yeast itself could be isolated easily using the ammonium sulfate salting‐out method. [ABSTRACT FROM AUTHOR]

Here, we evaluated the effect of linkers conjugating a chlorin-based photosensitizer, 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a ( HPPH), and folic acid to target cancer cells. Folate- HPPH conjugates with peptide, polyethylene glycol ( PEG), peptoid, or 7-aminoheptanoic acid ( AHA) linkers were synthesized on a solid-phase and evaluated for photodynamic therapy ( PDT) efficacy. Compared to free HPPH, the folate-linker- HPPHs were effectively internalized into tumor cells and exhibited superior PDT effect upon irradiation. Tumor-targeting PDT efficacy was influenced by linker variation, with in vitro photocytotoxicities of peptide > PEG > AHA > peptoid, paralleling water solubility of the linkers. Thus, linker choice significantly affects targeted PDT efficacy providing useful information for linker design. [ABSTRACT FROM AUTHOR]

A kinetic study on nucleophilic substitution reactions of 4-pyridyl benzoate ( 2a) and O-4-pyridyl thionobenzoate ( 2b) with a series of cyclic secondary amines in acetonitrile at 25.0°C is reported. Plots of pseudo-first-order rate constant ( kobsd) vs. [amine] are linear and pass through the origin for the reactions of 2a but curve upward for those of 2b. The upward curvature observed for the reactions of 2b is typical for reactions that proceed through a stepwise mechanism with a zwitterionic intermediate T±, which decomposes to the products via uncatalyzed and catalyzed routes competitively. The reaction of 2a has been suggested to proceed through a stepwise mechanism with T±, in which expulsion of the leaving group occurs in the rate-determining step on the basis of a linear Brønsted-type plot with βnuc = 0.77. The catalyzed reaction of 2b from T± has been proposed to proceed through a concerted mechanism with a six-membered cyclic transition state rather than via a stepwise pathway with an anionic intermediate T−. Factors influencing reactivity and reaction mechanism are discussed in detail. [ABSTRACT FROM AUTHOR]

Rhamnetin, a natural flavonoid found in cloves and berries has been reported to show anti-inflammatory activities in lipopolysaccharide-stimulated RAW264.7 cells and may be a potent inhibitor for extracellular signal-regulated kinase 1 ( ERK1) and c-Jun N-terminal kinase. Here, we showed that rhamnetin has antimycobacterial effects on Mycobacterium tuberculosis ( MT) H37Rv, multi-drug-, and extensively drug-resistant clinical isolates. We also investigated the effect of rhamnetin on interferon ( IFN)-γ-stimulated human lung fibroblast MRC-5 cells, since MT infection causes intensive lung inflammation. Rhamnetin suppressed mRNA levels of tumor necrosis factor-α, interleukin ( IL)-1β, IL-6, IL-12, and matrix metalloproteinase-1. Furthermore, it inhibited IFN-γ-mediated stimulation of ERK1 and p38 mitogen-activated protein kinase in MRC-5 cells. These results showed that rhamnetin has potent anti-tuberculosis activities and effectively suppresses lung inflammation, implying that rhamnetin can be a potent anti-tuberculosis dietary agent. [ABSTRACT FROM AUTHOR]

Pseudo-first-order rate constants ( kobsd) for nucleophilic substitution reaction of O-2-pyridyl thionobenzoate ( 7) with a series of secondary amines in MeCN at 25.0 ± 0.1°C have been measured spectrophotometrically. The plots of kobsd vs. [amine] curve upward, indicating that the reaction proceeds through a stepwise mechanism with a zwitterionic tetrahedral intermediate (T±), which decomposes to the products through uncatalyzed and catalyzed routes. It has been proposed that the uncatalyzed reaction proceeds through a six-membered cyclic transition state ( TS), in which expulsion of the leaving group occurs in the rate-determining step. The catalyzed reaction from T± proceeds through a concerted mechanism with a six-membered cyclic TS rather than via a stepwise pathway with an anionic intermediate T−. This is in contrast to the report that the corresponding reaction of 2-pyridyl benzoate ( 6, a CO analogue of 7) proceeds through a forced concerted mechanism. Comparison of the second-order rate constants for the uncatalyzed reaction of 7 with those reported previously for the corresponding reaction of 6 has revealed that 7 is much more reactive than 6. Factors that affect the reactivity and reaction mechanism are discussed in detail. [ABSTRACT FROM AUTHOR]

Two new DNA probes bearing a fluorescent deoxyguanosine unit labeled with 2-ethynylfluorene ( GFL) or 2-ethynylfluorenone ( GFO) were synthesized and examined for their efficiency as quencher-free linear beacon probes. Oligodeoxynucleotides ( ODNs) containing a GFL or GFO unit exhibit low thermal selectivity and few distinctive fluorescence changes upon duplex formation due to the syn conformation about the glycosidic bond. An exciplex emission was observed when the GFL unit of ODNs bearing adenine flanking bases was positioned opposite to the adenine nucleobases. [ABSTRACT FROM AUTHOR]

In this study, colloidal silica microparticles containing solubilizing excipient were prepared using the spray-drying process to enhance dissolution and oral absorption of lercanidipine hydrochloride. Several measurements including scanning electron microscopy, powder X-ray diffraction, particle size determination, in vitro dissolution, and pharmacokinetic study were conducted in rats. Among the tested solubilizing excipients, d-α-tocopheryl polyethylene glycol 1000 succinate ( TPGS) dramatically enhanced the solubility of lercanidipine hydrochloride through micelle solubilization. In addition, TPGS-colloidal silica microparticles at the ratio of 1:10:10 (drug: TPGS:colloidal silica) showed rapid dissolution rate in all dissolution media and displayed higher area under the curve and maximum plasma concentration values compared with raw lercanidipine hydrochloride. Therefore, amorphous TPGS-colloidal silica microparticles fabricated using the spray-drying process have great potential in the clinical application of lercanidipine hydrochloride. [ABSTRACT FROM AUTHOR]

Ethylbenzene ( EB) and p-xylene ( PX) are important chemicals for the production of industrial materials; accordingly, their efficient separation is desired, even though the difference in their boiling points is very small. This paper describes the efforts toward the identification of high-performance extractive agents for EB and PX separation by distillation. Most high-performance extractive agents contain halogen atoms, which present health hazards and are corrosive to distillation plates. To avoid this disadvantage of extractive agents, we developed a quantitative structure-relative volatility relationship ( QSRVR) model for designing safe extractive agents. We have previously developed and reported QSRVR models for single extractive agents. In this study, we introduce extended QSRVR models for binary and ternary extractive agents. The QSRVR models accurately predict the relative volatilities of binary and ternary extractive agents. The service to predict the relative volatility for binary and ternary extractive agents is freely available from the Internet at . [ABSTRACT FROM AUTHOR]

Second-order rate constants ( kN) for nucleophilic displacement reactions of phenyl Y-substituted phenyl carbonates ( 7a-7l) with 1,8-diazabicyclo[5.4.0]undec-7-ene ( DBU) in 80 mol % H2O/20 mol % DMSO at 25.0 ± 0.1 oC have been measured spectrophotometrically. The Brønsted-type plot for the reactions of 7a-7l with DBU is linear with βlg = -0.48, indicating that the reactions proceed through a concerted mechanism, which is in contrast to the stepwise mechanism reported previously for the corresponding reactions with ethylamine (a primary amine) and piperidine (a secondary amine). The Hammett plots correlated with σ− and σo constants exhibit many scattered points. In contrast, the Yukawa-Tsuno plot results in an excellent linear correlation with ρY = 1.27 and r = 0.57, implying that a negative charge develops partially on the O atom of the leaving group in the transition state. The bulky DBU is less reactive than the primary and secondary amines toward substrates possessing a weakly basic leaving group. It has been concluded that steric hindrance exerted by DBU in the plausible intermediate (T±) forces the reactions to proceed through a concerted mechanism because expulsion of the leaving group from T± could reduce the steric hindrance. [ABSTRACT FROM AUTHOR]

Second-order rate constants ( kN3−) for SNAr reactions of 1-(Y-substituted-phenoxy)-2,4-dinitrobenzenes ( 2a-2h) with [ABSTRACT FROM AUTHOR]

Second-order rate constants ( kquin) have been measured spectrophotometrically for the reactions of O-3,4-dinitrophenyl thionobenzoate ( 1a) with a series of quinuclidine derivatives and of O-4-nitrophenyl X-substituted thionobenzoates ( 2a-2f) with quinuclidine in 80 mol% H2O/20 mol% DMSO at 25.0 ± 0.1 °C. Quinuclidine is less reactive toward the thione esters than less basic benzylamine. Steric hindrance exerted by the tertiary amine is responsible for the decreased reactivity. The Hammett plot for the reactions of 2a-2f with quinuclidine consists of two intersecting straight lines, while the Yukawa-Tsuno plot for the same reactions exhibits an excellent linear correlation with ρ X = 1.10 and r = 0.71. This indicates that the nonlinear Hammett plot is not due to a change in the rate-determining step but is caused by ground-state stabilization of substrates possessing an electron-donating group in the thionobenzoyl moiety through resonance interactions. Brønsted-type plot for the reactions of 1a with quinuclidines is linear with βnuc = 0.89, which is typical for reactions reported to proceed through a stepwise mechanism. However, the reactions have been concluded to proceed through a forced concerted mechanism. Instability of a plausible intermediate T± forces the reactions to proceed through such a mechanism. [ABSTRACT FROM AUTHOR]

Second-order rate constants () for alkaline hydrolysis of 2,4-dinitrophenyl X-substituted benzenesulfonates ( 1a-1f) and Y-substituted phenyl 4-nitrobezenesulfonates ( 2a-2g) have been measured spectrophotometrically. Comparison of with the values reported previously for the corresponding reactions with has revealed that OH is only 103-fold more reactive than , although the former is 11 p Ka units more basic than the latter. The Yukawa-Tsuno plot for the reactions of 1a-1f results in an excellent linear correlation with ρX = 2.09 and r = 0.41. The Brønsted-type plot for the reactions of 2a-2g is linear with βlg = −0.51, which is typical for reactions reported to proceed through a concerted mechanism. The Yukawa-Tsuno plot for the reactions of 2a-2g exhibits excellent linearity with ρY = 1.85 and r = 0.25, indicating that a partial negative charge develops on the O atom of the leaving group in the transition state. Thus, the alkaline hydrolysis of 1a-1f and 2a-2g has been concluded to proceed through a concerted mechanism. Comparison of the ρX and βlg values for the reactions with ions suggests that the reactions with hydroxide ion proceed through a tighter transition-state structure than those with azide ion. [ABSTRACT FROM AUTHOR]

The second-order rate constants for reactions of 2,4-dinitrophenyl X-substituted-benzenesulfonates ( 4a-4f) and Y-substituted-phenyl-4-nitrobenzenesulfonates ( 5a-5f) with [ABSTRACT FROM AUTHOR]

Second-order rate constants ( kN) have been measured spectrophotometrically for reactions of Y-substituted-phenyl picolinates ( 7a-7i) with a series of quinuclidines in 80 mol% H2O/20 mol% DMSO at 25.0 ± 0.1 °C. The Brønsted-type plot for the reactions of 7a-7i with quinuclidine is linear with βlg = −0.80. The Yukawa-Tsuno plot exhibits an excellent linear correlation with ρY = 2.37 and r = 0.52, indicating that a negative charge develops partially on the O atom of the leaving group in the rate-determining transition state ( TS). The Brønsted-type plot for the reactions of 2-chloro-4-nitrophenyl picolinate ( 7a) with a series of quinuclidines is also linear with βnuc = 0.83. Thus, it was concluded that the reactions proceed through a stepwise mechanism, in which expulsion of the leaving group occurs in the rate-determining step. Comparison of the current kinetic data with those reported previously for the corresponding reactions with piperidine revealed that quinuclidine is ca. 102-fold less reactive than piperidine. This is in contrast to the reports that quinuclidines are more reactive than isobasic secondary amines toward diaryl carbonates and related esters. Effects of amine nature on reactivity and TS structures are discussed. [ABSTRACT FROM AUTHOR]

Second-order rate constants ( kOH-) for alkaline hydrolysis of Y-substituted phenyl picolinates ( 6a-6i) have been measured spectrophotometrically. A linear Brønsted-type plot is obtained with βlg = −0.34, which is typical for reactions reported previously to proceed through a stepwise mechanism with formation of an addition intermediate being the rate-determining step ( RDS). However [ABSTRACT FROM AUTHOR]

Second-order rate constants ( kquin) for the reactions of O- Y-substituted phenyl thionobenzoates ( 3a-3i) with quinuclidine have been measured spectrophotometrically. Comparison of kquin with the rate constants reported previously for the corresponding reactions with benzylamine ( kBzNH2) has revealed that quinuclidine is less reactive than benzylamine toward 3a-3i although the former is 2.1 p Ka units more basic than the latter. Steric hindrance exerted by quinuclidine has been suggested to be responsible for the decreased reactivity of the tertiary amine. The Brønsted-type plot for the reactions of 3a-3i with quinuclidine is linear with βlg = −0.37. The Hammett plot correlated with [ABSTRACT FROM AUTHOR]

The article focuses on a research on palladium-catalyzed asymmetric hydrosilylation of styrene and its derivatives with chiral phosphoramidite ligands containing chiral ferrocenyl amine. Topics include examining the reactivity and enantioselectivity of the hydrosilylation of styrene using diastereomeric ferrocenyl phosphoramidite ligands; high catalytic activity and enantioselectivity for hydrosilylation of styrene and its derivatives; and synthesis of chiral ferrocenyl secondary amines.

The article focuses on a research related to use of silver glutathione nanoclusters as a light harvester for metal-cluster-sensitized solar cells. Topics include capability of metal nanoclusters (NCs) in electron transfer; formation of discrete energy levels based on the quantum confinement effect and providing indirect evidence for electron transfer in photoluminescence (PL) quenching; and incident-photon-to-current efficiency (IPCE) of the silver glutathione-sensitized solar cell.

A kinetic study on SNAr reactions of 1-halo-2,4-dinitrobenzenes ( 6a-6d) with alkali-metal ethoxides ( EtOM; M = Li, Na, K and 18-crown-6-ether-complexed K) is reported. The plots of pseudo-first-order rate constant ( kobsd) vs. [ EtOM] curve upward or downward depending on the size of M+ ions. The reactions are catalyzed or inhibited by the M+ ions, e.g., the large K+ ion complexed by 18-crown-6-ether ( 18C6) acts as a catalyst while the small Li+ and Na+ ions behave as an inhibitor. Reactivity of 6a-6d toward EtOM decreases linearly as the halide ion becomes less basic regardless of the size of M+ ions, indicating that expulsion of the leaving group occurs after the rate-determining step ( RDS). Thus, the reactions have been proposed to proceed through a stepwise mechanism with formation of a Meisenheimer complex being the RDS. Computational studies using B3LYP density functional theory have revealed that Mulliken charge density of the electrophilic center decreases as the halogen atom becomes less electronegative. Thus, it has been concluded that the SNAr reactivity of 6a-6d toward EtOM is governed by electrophilicity of the reaction center but not by nucleofugality of the leaving group. A π-complexed transition-state structure has been proposed to account for the experimental and computational results. [ABSTRACT FROM AUTHOR]

To develop a topical preparation of hirsutenone ( HST), a natural immunomodulator, we formulated oleaginous ointments and creams and assessed their stability in terms of shelf-life. Ointments were prepared by mixing the molten lipid phase of white petrolatum and white beeswax with glycerin and propylene glycol, in which HST was dissolved with ascorbyl palmitate ( AP), butylated hydroxyl toluene ( BHT), or ethylenediaminetetraacetic acid ( EDTA) as an antioxidant. Reference oil-in-water creams were formulated by conventional emulsification. The ointment and cream formulations were subjected to accelerated stability testing at 40 °C. At appropriate time points, test samples were dissolved in organic solvent, diluted with methanol, and filtered prior to high-performance liquid chromatography ( HPLC). The degradation of HST in cream and ointment formulations followed first-order kinetics. The rate constants (day−1) of HST in cream and ointments were 1.71 × 10−2 and 0.67 × 10−2, respectively, revealing a 2.5-fold greater half-life in ointments than in creams. Although AP and BHT had no effect on chemical stabilization of ointments, EDTA enhanced the stability of HST at 40 °C. The shelf-lives of HST formulations were estimated by the Q10 method. Assuming a Q10 value of 2, the shelf-lives (days) of cream, ointment, and ointment with EDTA at 25 °C were 14.99, 38.23, and 44.19, respectively. At 4 °C, the shelf-life of HST in ointment with EDTA was extended to 220 days. Even though the stability of HST was somewhat increased by the ointment formulation and further improved by adding EDTA, alternative approaches are needed to increase stabilization. [ABSTRACT FROM AUTHOR]

The article discusses the spectroscopic analysis and preparation results of xanthene-type dyes , where triazole ring was introduced to xanthene-type dyes by copper-catalyzed azide–alkyne cycloaddition reaction. Topics include an ethynyl group being introduced to xanthone through addition reaction, figure showing synthesis of xanthene-based dyes and the click ckemistry.

The article discusses an analyses in laser ablation of graphene oxide (GO) focusing on observations of even numbered carbon clusters. Topics include observation of Ultrahigh-resolution (UHR) mass spectra of GO, laser desorption ionization (LDI) of GO, and formation mechanism of the carbon cluster.

The article discusses the spectroscopic analysis and preparation results of xanthene-type dyes , where triazole ring was introduced to xanthene-type dyes by copper-catalyzed azide–alkyne cycloaddition reaction. Topics include an ethynyl group being introduced to xanthone through addition reaction, figure showing synthesis of xanthene-based dyes and the click ckemistry.

The article discusses an analyses in laser ablation of graphene oxide (GO) focusing on observations of even numbered carbon clusters. Topics include observation of Ultrahigh-resolution (UHR) mass spectra of GO, laser desorption ionization (LDI) of GO, and formation mechanism of the carbon cluster.