Microchip extraction of catecholamines using a boronic acid functional affinity monolith

We report on the development of a rapid enzyme logic gate-based electrochemical assay for the assessment of traumatic brain injury (TBI). The concept harnesses a biocatalytic cascade that emulates the functionality of a Boolean NAND gate in order to process relevant physiological parameters in the biochemical domain. The enzymatic backbone ensures that a high-fidelity diagnosis of traumatic brain injury can be tendered in a rapid fashion when the concentrations of key serum-based biomarkers reach pathological levels. The excitatory neurotransmitter glutamate and the enzyme lactate dehydrogenase were used here as clinically-relevant input TBI biomarkers, in connection to the low-potential detection of the NADH product in the presence of methylene green at a glassy carbon electrode. A systematic optimization of the gate and the entire protocol has resulted in the effective discrimination between the physiological and pathological logic levels. Owing to its robust design, the enzyme-based logic gate mitigates potential interferences from both physiological and electroactive sources and is able to perform direct measurements in human serum samples. Granted further detailed clinical validation, this proof-of-concept study demonstrates the potential of the electrochemical assay to aid in the rapid and decentralized diagnosis of TBI.     

Synthesis of phenylalkyl-substituted polyhydroxypiperidines as potent inhibitors for α-l-fucosidase

Synthesis and inhibitory activities against α-l-fucosidase of phenylalkyl-substituted polyhydroxypiperidines have been described. Among the newly synthesized compounds, 2,4,6-trichloro derivative (16q) showed very high inhibitory activity against α-l-fucosidase with IC₅₀ value of 0.005 μM, and K_i values of 0.0011 μM, respectively.     

Directing the Structural Features of N2‐Phobic Nanoporous Covalent Organic Polymers for CO2 Capture and Separation

A family of azo‐bridged covalent organic polymers (azo‐COPs) was synthesized through a catalyst‐free direct coupling of aromatic nitro and amine compounds under basic conditions. The azo‐COPs formed 3D nanoporous networks and exhibited surface areas up to 729.6 m² g^?1, with a CO₂‐uptake capacity as high as 2.55 mmol g^?1 at 273 K and 1 bar. Azo‐COPs showed remarkable CO₂/N₂ selectivities (95.6–165.2) at 298 K and 1 bar. Unlike any other porous material, CO₂/N₂ selectivities of azo‐COPs increase with rising temperature. It was found that azo‐COPs show less than expected affinity towards N₂ gas, thus making the framework “N₂‐phobic”, in relative terms. Our theoretical simulations indicate that the origin of this unusual behavior is associated with the larger entropic loss of N₂ gas molecules upon their interaction with azo‐groups. The effect of fused aromatic rings on the CO₂/N₂ selectivity in azo‐COPs is also demonstrated. Increasing the π‐surface area resulted in an increase in the CO₂‐philic nature of the framework, thus allowing us to reach a CO₂/N₂ selectivity value of 307.7 at 323 K and 1 bar, which is the highest value reported to date. Hence, it is possible to combine the concepts of “CO₂‐philicity” and “N₂‐phobicity” for efficient CO₂ capture and separation. Isosteric heats of CO₂ adsorption for azo‐COPs range from 24.8–32.1 kJ mol^?1 at ambient pressure. Azo‐COPs are stable up to 350 °C in air and boiling water for a week. A promising cis/trans isomerization of azo‐COPs for switchable porosity is also demonstrated, making way for a gated CO₂ uptake.     

Molecular dynamics simulation of dissociation behavior of various crystalline celluloses treated with hot-compressed water

The dissociation behavior of the crystalline cellulose polymorphs I_β, II, III_I, and IV_I (Cell I_β, etc.) at 503 K and 100 bar was studied by molecular dynamics simulation, and the mechanism of the experimental liquefaction during treatment with hot-compressed water was elucidated. The results showed that the mini-crystals of Cell I_β and Cell IV_I exhibited similar resistance to dissociation, which implies the occurrence of crystal transformation from Cell IV_I to Cell I. On the other hand, the mini-crystal of Cell II gradually dissociated into the water environment with the progress of time in the simulation. The water molecules gradually penetrated the Cell II crystal, especially along the (1 \(\overline{1}\) 0) crystal plane. In contrast, the dissolution behavior differed for the surface and the core areas of the mini-crystal of Cell III_I. The cellulose chains on the surface were dissociated into the water environment, whereas the ordered structure of the chains in the core region was maintained for the entire simulation period. The detailed investigation showed that the core part of Cell III_I was transformed into Cell I at an early stage of the simulation: Cell I is resistant to dissociation of the structure even in the hot-compressed water environment. It can be confirmed that the stability of these four crystals under high temperature and pressure conditions follows the order: Cell II < III_I < IV_I ≈ I_β.     

Covalent Scrambling in Porous Polyarylthioethers through a Stepwise SNAr for Tunable Bandgap and Porosity

Porous poly(aryl thioether)s offer stability and electronic tunability by robust sulfur-aryl conjugated architecture, but synthetic access is hindered due to limited control over the nucleophilic nature of sulfides and the air sensitivity of aromatic thiols. Here, we report a simple, one-pot, inexpensive, regioselective synthesis of highly porous poly(aryl thioether)s through polycondensation of perfluoroaromatic compounds with sodium sulfide. The unprecedented temperature-dependent para-directing formation of thioether linkages leads to a stepwise transition of the polymer extension into a network, thereby allowing fine control of the porosity and optical band gaps. The obtained porous organic polymers with ultra-microporosity (<1 nm) and sulfur as the surface functional groups show size-dependent separation of organic micropollutants and selective removal of mercury ions from water. Our findings offer easy access to poly(aryl thioether)s with accessible sulfur functionalities and higher complexity, which will help in realizing advanced synthetic designs in applications such as adsorption, (photo)catalysis, and (opto)electronics.     

Plasma Treated Sepiolite: A New Adsorbent for Removal of Malachite Green from Contaminated Water

Surface modification of clay materials has become an important issue to improve the efficiency of the adsorbent. The adsorption capacity of the clay material can be increased by thermal or chemical modifications. In this study, plasma technology was applied for the surface modification of sepiolite to improve the removal of malachite green from contaminated water. This study is novel in preparing and examining the effectiveness of sepiolite in adsorption of malachite green from contaminated water. To achieve the aim, plasma application time, CO₂, N₂, or Ar plasma gases effect and pH were investigated with respect to the adsorption capacity of MG. The surface properties of raw and plasma treated sepiolite were investigated with SEM, FTIR, BET surface area and XRD measurements. The monolayer adsorption capacity was found to be 143 mg/g.     

Structural analysis and antitumor potential of novel 5,6-disubstituted-17a-homo-17-oxa-androstane derivatives

Starting from 3β-acetoxy-17a-homo-17-oxa-androst-5-en-16-one (1) and in the reaction with N-bromoacetamide (NBA) and perchloric acid, the 5α-bromo-6β-hydroxy (2), 5β,6β-epoxy (3) and 5α,6β-dibromo (4) derivatives were obtained. The structure of compounds 2–4, particularly stereochemistry at C5 and C6, is established by detailed NMR and X-ray analysis. The in vitro antiproliferative activity of newly synthesized compounds 2–4 against six human tumor cell lines was evaluated. All three compounds showed a significant toxicity toward hormone-independent breast adenocarcinoma MDA-MB-231 and cervical carcinoma cells HeLa, while dibromo derivative 4 was active toward five human cancer cell lines. These new 5,6-disubstituted-D-homolactone steroidal compounds have also displayed selectivity toward cancerous cell lines against inactivity found for noncancerous control cell line. This selectivity was not found for control compound, well-known chemotherapy drug cisplatin.     

Finite size melting of spherical solid–liquid aluminium interfaces

We have investigated the melting of nano-sized cone shaped aluminium needles coated with amorphous carbon using transmission electron microscopy. The interface between solid and liquid aluminium was found to have spherical topology. For needles with fixed apex angle, the depressed melting temperature of this spherical interface, with radius R, was found to scale linearly with the inverse radius 1/R. However, by varying the apex angle of the needles we show that the proportionality constant between the depressed melting temperature and the inverse radius changes significantly. This led us to the conclusion that the depressed melting temperature is not controlled solely by the inverse radius 1/R. Instead, we found a direct relation between the depressed melting temperature and the ratio between the solid–liquid interface area and the molten volume.     

Solvent and central metal effects on the photophysical and photochemical properties of 4-benzyloxybenzoxy substituted phthalocyanines

The synthesis and characterization of new peripherally tetra-4-benzyloxybenzoxy substituted metal-free, zinc and lead phthalocyanines are described for the first time in this study. The influence of various organic solvents and the nature of the central metal ion on the spectroscopic, photophysical and photochemical properties has been investigated. General trends are described for photodegradation, singlet oxygen and fluorescence quantum yields, and fluorescence lifetimes of these compounds in different solvents. Photophysical and photochemical properties of phthalocyanine compounds are very useful for photodynamic therapy applications. Especially high singlet oxygen quantum yields are very important for Type II mechanism. The studied phthalocyanine compounds showed good singlet oxygen generation and these compounds show potential as Type II photosensitizers. The fluorescences of the studied compounds are effectively quenched by 1,4-benzoquinone in different solvents.     

Gas- and solid/liquid-phase reactions during pyrolysis of softwood and hardwood lignins

Pyrolytic reactions of Japanese cedar (Cryptomeria japonica, a softwood) and Japanese beech (Fagus crenata, a hardwood) milled wood lignins (MWLs) were studied with thermogravimetry (TG) and by pyrolysis in a closed ampoule reactor (N₂/600 °C). The data were compared with those of guaiacol/syringol as simple lignin model aromatic nuclei. Several DTG peaks were observed around 300-350, 450, 590 and 650 °C. The first DTG peak temperature (326 °C) of beech was lower than that (353 °C) of cedar. This indicates that the volatile formation from cedar MWL is slightly delayed in heating at 600 °C. The gas-phase reactions via GC/MS-detectable low MW products were explainable with the temperature-dependent reactions observed for guaiacol/syringol in our previous paper. The methoxyl groups became reactive at ∼450 °C, giving O-CH₃ homolysis products (catechols/pyrogallols) and OCH₃ rearrangement products (cresols/xylenols). The former homolysis products were effectively converted into gaseous products (mainly CO) at >550-600 °C. However, the GC/MS-detectable tar yields, especially syringyl unit-characteristic products, were much lower than those from guaiacol/syringol. Thus, contributions of higher MW intermediates and solid/liquid-phase reactions are more important in lignin pyrolysis. From the results of stepwise pyrolysis of char + coke fractions at 450 and 600 °C, the methoxyl group-related reactions (450 °C) and intermediates gasification (600 °C) were suggested to occur also in the solid/liquid phase. This was consistent with the DTG peaks observed around these temperatures. These solid/liquid-phase reactions reduced the tar formation, especially catechols/pyrogallols and PAHs. Different features observed between these two MWLs are also focused.