Direct Arylation of Benzyl Ethers with Organozinc Reagents.

A novel C(sp3)-H bond arylation of benzyl ethers with Knochel-type arylzinc reagents has been developed. This transition-metal-catalyst-free reaction proceeds well under mild conditions in a simple and effective manner and enables the synthesis of a wide range of potentially biologically active benzyl ethers by using highly functionalized organozinc reagents as a carbon nucleophile.

Monitoring and Control of an Adsorption System Using Electrical Properties of the Adsorbent for Organic Compound Abatement.

Adsorption systems typically need gas and temperature sensors to monitor their adsorption/regeneration cycles to separate gases from gas streams. Activated carbon fiber cloth (ACFC)-electrothermal swing adsorption (ESA) is an adsorption system that has the potential to be controlled with the electrical properties of the adsorbent and is studied here to monitor and control the adsorption/regeneration cycles without the use of gas and temperature sensors and to predict breakthrough before it occurs. The ACFC's electrical resistance was characterized on the basis of the amount of adsorbed organic gas/vapor and the adsorbent temperature. These relationships were then used to develop control logic to monitor and control ESA cycles on the basis of measured resistance and applied power values. Continuous sets of adsorption and regeneration cycles were performed sequentially entirely on the basis of remote electrical measurements and achieved ≥95% capture efficiency at inlet concentrations of 2000 and 4000 ppmv for isobutane, acetone, and toluene in dry and elevated relative humidity gas streams, demonstrating a novel cyclic ESA system that does not require gas or temperature sensors. This contribution is important because it reduces the cost and simplifies the system, predicts breakthrough before its occurrence, and reduces emissions to the atmosphere.

The transition-metal-catalyst-free oxidative homocoupling of organomanganese reagents prepared by the insertion of magnesium into organic halides in the presence of MnCl2·2LiCl.

Organomanganese reagents were prepared by the insertion of magnesium into aryl halides in the presence of MnCl2·2LiCl. These organomanganese reagents smoothly undergo 1,2-addition, acylation, and Pd-catalyzed cross-coupling with various electrophiles. Especially, the oxidative homocoupling of organomanganese reagents was completed in one pot without an additional transition-metal catalyst.

Modulating lipid bilayer permeability and structure: Impact of hydrophobic chain length, C-3 hydroxyl group, and double bond in sphingosine.

Sphingosine, an amphiphilic molecule, plays a pivotal role as the core structure of sphingolipids, essential constituents of cell membranes. Its unique capability to enhance the permeability of lipid membranes profoundly influences crucial life processes. The molecular structure of sphingosine dictates its mode of entry into lipid bilayers and governs its interactions with lipids, thereby determining membrane permeability. However, the incomplete elucidation of the relationship between the molecular structure of sphingosine and the permeability of lipid membranes persists due to challenges associated with synthesizing sphingosine molecules. A series of sphingosine-derived molecules, featuring diverse hydrophobic chain lengths and distinct headgroup structure, were meticulously designed and successfully synthesized. These molecules were employed to investigate the permeability of large unilamellar vesicles, functioning as model lipid bilayers. With a decrease in the hydrophobic chain length of sphingosine from C15 to C11, the transient leakage ratio of vesicle contents escalated from âˆ¼ 13 % to âˆ¼ 28 %. Although the presence of double bond did not exert a pronounced influence on transient leakage, it significantly affected the continuous leakage ratio. Conversely, modifying the chirality of the C-3 hydroxyl group gives the opposite result. Notably, methylation at the C-3 hydroxyl significantly elevates transient leakage while suppressing the continuous leakage ratio. Additionally, sphingosines that significantly affect vesicle permeability tend to have a more pronounced impact on cell viability. Throughout this leakage process, the charge state of sphingosine-derived molecule aggregates in the solution emerged as a pivotal factor influencing vesicle permeability. Fluorescence lifetime experiments further revealed discernible variations in the effect of sphingosine molecular structure on the mobility of hydrophobic regions within lipid bilayers. These observed distinctions emphasize the impact of molecular structure on intermolecular interactions, extending to the microscopic architecture of membranes, and underscore the significance of subtle alterations in molecular structure and their associated aggregation behaviors in governing membrane permeability.

Reduced arsenic clearance and increased toxicity in aquaglyceroporin-9-null mice.

Expressed in liver, aquaglyceroporin-9 (AQP9) is permeated by glycerol, arsenite, and other small, neutral solutes. To evaluate a possible protective role, AQP9-null mice were evaluated for in vivo arsenic toxicity. After injection with NaAsO(2), AQP9-null mice suffer reduced survival rates (LD(50), 12 mg/kg) compared with WT mice (LD(50), 15 mg/kg). The highest tissue level of arsenic is in heart, with AQP9-null mice accumulating 10-20 times more arsenic than WT mice. Within hours after NaAsO(2) injection, AQP9-null mice sustain profound bradycardia, despite normal serum electrolytes. Increased arsenic levels are also present in liver, lung, spleen, and testis of AQP9-null mice. Arsenic levels in the feces and urine of AQP9-null mice are only approximately 10% of the WT levels, and reduced clearance of multiple arsenic species by the AQP9-null mice suggests that AQP9 is involved in the export of multiple forms of arsenic. Immunohistochemical staining of liver sections revealed that AQP9 is most abundant in basolateral membrane of hepatocytes adjacent to the sinusoids. AQP9 is not detected in heart or kidney by PCR or immunohistochemistry. We propose that AQP9 provides a route for excretion of arsenic by the liver, thereby providing partial protection of the whole animal from arsenic toxicity.

Differential influences of serum vitamin C on blood pressure based on age and sex in normotensive individuals.

Aim: Hypertension is among the most prevalent chronic diseases with diverse etiology, affecting over 1 billion people globally. In numerous studies, vitamin C inversely correlated with blood pressure and was suspected to have antihypertensive properties. Currently, there is conflicting evidence regarding the relationship between vitamin C and blood pressure, with most studies being conducted on hypertensive subjects. The principal objective of this project was to investigate the relationship between vitamin C and blood pressure in normotensive adult subjects. Methods: A total of 2,533 individuals aged 20 years and above were enrolled in the present study from the National Health and Nutrition Examination Survey (NHANES) 2017-2018. Outcome variables were systolic blood pressure (SBP) and diastolic blood pressure (DBP). Serum vitamin C was regarded as an independent variable. EmpowerStats software and R (version 3.4.3) were used to examine the association between vitamin C and SBP or DBP. Results: Vitamin C was reversely correlated with both SBP (ß = -0.02, 95% CI: -0.03 to -0.00, p = 0.0306) and DBP (ß = -0.02, 95% CI: -0.04 to -0.01, p = <0.0011) after adjusting all covariates. This reverse relationship may be affected by a number of factors, including a person's gender, age, race, and ethnicity. A U-shaped association between vitamin C and SBP in females and an inverted one between vitamin C and DBP in males were detected, respectively. We further calculated the inflection points at 90.3 µmol/L for females and 40 µmol/L for males. It is somewhat surprising that a reverse U-shaped distribution between vitamin C and SBP and DBP in people over 50 was detected, and the point of inflection of vitamin C were all located at 40 µmol/L. Conclusion: Vitamin C was negatively correlated with both SBP and DBP in this cross-sectional analysis. However, a U-shaped relationship and an inverted one were also observed in certain people, which implied that, though vitamin C is considered a vital antioxidant, maintaining vitamin C at appropriate levels may be beneficial according to different populations.

Osteoclast differentiation and function in aquaglyceroporin AQP9-null mice.

BACKGROUND INFORMATION: Osteoclasts are cells specialized for bone resorption and play important roles in bone growth and calcium homoeostasis. Differentiation of osteoclasts involves fusion of bone marrow macrophage mononuclear precursors in response to extracellular signals. A dramatic increase in osteoclast cell volume occurs during osteoclast biogenesis and is believed to be mediated by AQP9 (aquaporin 9), a membrane protein that can rapidly transport water and other small neutral solutes across cell membranes. RESULTS: In the present study we report an increase in expression of AQP9 during differentiation of a mouse macrophage cell line into osteoclasts. Bone marrow macrophages from wild-type and AQP9-null mice differentiate into osteoclasts that have similar morphology, contain comparable numbers of nuclei, and digest synthetic bone to the same extent. Bones from wild-type and AQP9-null mice contain similar numbers of osteoclasts and have comparable density and structure as measured by X-ray absorptiometry and microcomputed tomography. CONCLUSIONS: Our results confirm that AQP9 expression rises during osteoclast biogenesis, but indicate that AQP9 is not essential for osteoclast function or differentiation under normal physiological conditions.

Aquaporin 6 binds calmodulin in a calcium-dependent manner.

Aquaporin 6 (AQP6) is an anion channel that is expressed primarily in acid secreting alpha-intercalated cells of the kidney collecting duct. In addition, AQP6 anion channel permeability is gated by low pH. Inspection of the N-terminus of AQP6 revealed a putative calmodulin binding site. AQP6-expressing CHO-K1 cell lysates were mixed with calmodulin beads and AQP6 was pulled down in the presence of calcium. Mutagenesis of the N-terminal calmodulin binding site in full length mouse AQP6 resulted in a loss of calmodulin binding activity. Mouse and human AQP6 calmodulin binding site peptides bound dansyl-calmodulin with a dissociation constant of approximately 1microM. The binding of AQP6 to calmodulin may be an important key to determining the physiological role of AQP6 in the kidney.

Hydro-liquefaction of microcrystalline cellulose, xylan and industrial lignin in different supercritical solvents.

The influences of solvent on hydro-liquefaction of cellulose, xylan, and lignin were investigated using micro-autoclave. The maximum conversion and bio-oil yield obtained from cellulose and xylan liquefaction were achieved in methanol, whereas similar liquefaction characteristics of lignin were observed in methanol and ethanol. The molecular simulation of interactions between solvents and subcomponents indicated that methanol and ethanol were highly miscible with raw materials. GC-MS and FT-ICR MS characterization revealed that the chemical compositions of liquid products highly depended on the utilized feedstocks. Esters, ketones, and aldehydes were mainly produced from cellulose and xylan conversion, whereas aromatic compounds were primarily derived from lignin conversion. EA results showed that methanol favored the hydrogenation and deoxygenation, resulting in the heating value increased. It could be concluded that the oil quality was highly improved in supercritical methanol.

Effect of soil-rock system on speleothems weathering in Bailong Cave, Yunnan Province, China.

Bailong Cave with its well-developed Middle Triassic calcareous dolomite's system was opened as a show cave for visitors in 1988. The speleothem scenery has been strongly weathered as white powder on the outer layers. Study of the cave winds, permeability of soil-rock system and the chemical compositions of the dripping water indicated: (1) The cave dimension structure distinctively affects the cave winds, which were stronger at narrow places. (2) Based on the different soil grain size distribution, clay was the highest in composition in the soil. The response sense of dripping water to the rainwater percolation was slow. The density of joints and other openings in dolomite make the dolomite as mesh seepage body forming piles of thin and high columns and stalactites. (3) Study of 9 dripping water samples by HYDROWIN computer program showed that the major mineral in the water was dolomite.

Desulfurization of Saudi Arabian crudes by oxidation-extraction method.

The oxidation-extraction desulfurization of Saudi Arabian crudes was conducted with hydrogen peroxide-acetic acid oxidation system. The selection of extractant, the optimization of oxidation-extraction conditions, and the exploration of desulfurization mechanism were studied. As DMF was used as the extractant, the optimal desulfurization rate of 35.11 % and oil recovery of 95 % were obtained at 70 °C with the molar ratio of peracetic acid to sulfur of 8:1, the molar ratio of acetic acid to hydrogen peroxide of 2:1 and the volume ratio of extractant to oil of 1:1. The desulfurization effect of different fractions in the treated Saudi Arabian crudes was found to obey the following order: gasoline-diesel fraction >VGO fraction >VR fraction, due to different types and structures of sulfur compounds. The oil quality was less affected and most sulfides were mainly extracted via DMF.

Microwave assisted tandem Heck-Sonogashira reactions of N,N-di-Boc-protected 6-amino-5-iodo-2-methyl pyrimidin-4-ol in an efficient approach to functionalized pyrido[2,3-d]pyrimidines.

A microwave assisted tandem Heck-Sonogashira cross-coupling reaction between 6-N,N-di-Boc-amino-5-iodo-2-methyl pyrimidin-4-ol and various aryl alkynyl substrates has been developed. This process generates novel 5-enynyl substituted pyrimidines, which can be transformed to novel functionalized pyrido[2,3-d]pyrimidines by way of a silver catalyzed cyclization reaction.

Prediction on miscibility of silicone and gasoline components by Monte Carlo simulation.

The miscibility behavior between silicone materials and mixed gasoline components was explored via Monte Carlo simulation. The variation of energy of mixing and Gibbs energy of mixing between silicone and gasoline components shifted with temperature was calculated. The findings indicated that the miscibility of gasoline components was exceptional in silicone 2 and the selectivity of thiophene was superior to that of other silicones, which resulted from the ester groups and methyl side chains. The density of methyl side chains in silicone 2 was significantly higher than other silicones; therefore, it could explain the lower energy of mixing and higher selectivity concerning silicone 2 and thiophene. The energy of mixing between silicone 2 and gasoline components declined with the increasing temperature (300-500 K). Nevertheless, the more increased the temperature, the more decreased the selectivity of thiophene. At 350 K, it was essential for us to research the miscibility between silicone 2 and gasoline components further. The value of Gibbs energy of mixing for silicone 2 was considerably smaller than that of the hydrocarbons at 350 K. It could be demonstrated that the miscibility between silicone 2 and thiophene was better than that of hydrocarbons. Accordingly, we should attach importance to silicone 2 in the gasoline desulfurization process.

Direct hydro-liquefaction of sawdust in petroleum ether and comprehensive bio-oil products analysis.

The effect of temperature, time, hydrogen pressure and amount of catalyst on production distribution and the bio-oil yield obtained from the direct liquefaction of sawdust in the petroleum ether (60-90°C) are investigated. The highest sawdust conversion obtained was 72.32% with a bio-oil yield of 47.69% were obtained at 370°C, 40min and 5wt.% catalyst content with the initial H2 pressure of 3.0MPa. Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) approach was utilized to analyze the non-volatile fraction. In this study, the composition of bio-oil could be analyzed in an unprecedented detail through a combination of GC-MS and FT-ICR MS techniques.

Oxygen-containing functional group-facilitated CO2 capture by carbide-derived carbons.

A series of carbide-derived carbons (CDCs) with different surface oxygen contents were prepared from TiC powder by chlorination and followed by HNO3 oxidation. The CDCs were characterized systematically by a variety of means such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultimate analysis, energy dispersive spectroscopy, N2 adsorption, and transmission electron microscopy. CO2 adsorption measurements showed that the oxidation process led to an increase in CO2 adsorption capacity of the porous carbons. Structural characterizations indicated that the adsorbability of the CDCs is not directly associated with its microporosity and specific surface area. As evidenced by elemental analysis, X-ray photoelectron spectroscopy, and energy dispersive spectroscopy, the adsorbability of the CDCs has a linear correlation with their surface oxygen content. The adsorption mechanism was studied using quantum chemical calculation. It is found that the introduction of O atoms into the carbon surface facilitates the hydrogen bonding interactions between the carbon surface and CO2 molecules. This new finding demonstrated that not only the basic N-containing groups but also the acidic O-containing groups can enhance the CO2 adsorbability of porous carbon, thus providing a new approach to design porous materials with superior CO2 adsorption capacity.

A novel low-molecular weight inhibitor of focal adhesion kinase, TAE226, inhibits glioma growth.

Glioblastomas are highly lethal cancers that resist current therapies. Novel therapies under development target molecular mechanisms that promote glioblastoma growth. In glioblastoma patient specimens, the non-receptor tyrosine kinase focal adhesion kinase (FAK) is overexpressed. Upon growth factor receptor stimulation or integrin engagement, FAK is activated by phosphorylation on critical tyrosine residues. Activated FAK initiates a signal transduction cascade which promotes glioma growth and invasion by increasing cellular adhesion, migration, invasion, and proliferation. We find that human glioma cell lines express different levels of total FAK protein and activating phosphorylation of tyrosine residues Tyr397, Tyr861, and Tyr925. As all glioma cell lines examined expressed phosphorylated FAK, we examined the efficacy of a novel low-molecular weight inhibitor of FAK, TAE226, against human glioma cell lines. TAE226 inhibited the phosphorylation of FAK as well as the downstream effectors AKT, extracellular signal-related kinase, and S6 ribosomal protein in multiple glioma cell lines. TAE226 induced a concentration-dependent decrease in cellular proliferation with an associated G(2) cell cycle arrest in every cell line and an increase in apoptosis in a cell-line-specific manner. TAE226 also decreased glioma cell adhesion, migration, and invasion through an artificial extracellular matrix. Together, these data demonstrate the potential benefit of TAE226 for glioma therapy.