Direct Imaging of Atomically Dispersed Molybdenum that Enables Location of Aluminum in the Framework of Zeolite ZSM‐5

Integrated differential phase‐contrast scanning transmission electron microscopy (iDPC‐STEM) is capable of directly probing guest molecules in zeolites, owing to its sufficient and interpretable image contrast for both heavy and light elements under low‐dose conditions. This unique ability is demonstrated by imaging volatile organic compounds adsorbed in zeolite Silicalite‐1; iDPC‐STEM was then used to investigate molybdenum supported on various zeolites including Silicalite‐1, ZSM‐5, and mordenite. Isolated single‐Mo clusters were observed in the micropores of ZSM‐5, demonstrating the crucial role of framework Al in driving Mo atomically dispersed into the micropores. Importantly, the specific one‐to‐one Mo‐Al interaction makes it possible to locate Al atoms, that is, catalytic active sites, in the ZSM‐5 framework from the images, according to the positions of Mo atoms in the micropores.     

Novel copolymers of styrene. 5. Alkyl and alkoxy ring-disubstituted propyl 2-cyano-3-phenyl-2-propenoates

Novel trisubstituted ethylenes, alkyl and alkoxy ring-disubstituted propyl 2-cyano-3-phenyl-2-propenoates, RPhCH?C(CN)CO₂C₃H₇ (where R is 2,3-dimethyl, 2,5-dimethyl, 2,6-dimethyl, 3,4-dimethyl, 2,3-dimethoxy, 2,4-dimethoxy, 2,5-dimethoxy, 2,6-dimethoxy 3,4-dimethoxy, 3,5-dimethoxy) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and propyl cyanoacetate and characterized by CHN elemental analysis, IR, ¹H- and ¹³C-NMR. All the ethylenes were copolymerized with styrene (M₁) in solution with radical initiation (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C-NMR, GPC, DSC, and TGA. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (0.6–5.0% wt.), which then decomposed in the 500–800°C range.     

Remedia Sternutatoria over the Centuries: TRP Mediation

Sneezing (sternutatio) is a poorly understood polysynaptic physiologic reflex phenomenon. Sneezing has exerted a strange fascination on humans throughout history, and induced sneezing was widely used by physicians for therapeutic purposes, on the assumption that sneezing eliminates noxious factors from the body, mainly from the head. The present contribution examines the various mixtures used for inducing sneezes (remedia sternutatoria) over the centuries. The majority of the constituents of the sneeze-inducing remedies are modulators of transient receptor potential (TRP) channels. The TRP channel superfamily consists of large heterogeneous groups of channels that play numerous physiological roles such as thermosensation, chemosensation, osmosensation and mechanosensation. Sneezing is associated with the activation of the wasabi receptor, (TRPA1), typical ligand is allyl isothiocyanate and the hot chili pepper receptor, (TRPV1), typical agonist is capsaicin, in the vagal sensory nerve terminals, activated by noxious stimulants.     

Ionone Is More than a Violet’s Fragrance: A Review

The term ionone is derived from “iona” (Greek for violet) which refers to the violet scent and “ketone” due to its structure. Ionones can either be chemically synthesized or endogenously produced via asymmetric cleavage of β-carotene by β-carotene oxygenase 2 (BCO2). We recently proposed a possible metabolic pathway for the conversion of α-and β-pinene into α-and β-ionone. The differences between BCO1 and BCO2 suggest a unique physiological role of BCO2; implying that β-ionone (one of BCO2 products) is involved in a prospective biological function. This review focuses on the effects of ionones and the postulated mechanisms or signaling cascades involved mediating these effects. β-Ionone, whether of an endogenous or exogenous origin possesses a range of pharmacological effects including anticancer, chemopreventive, cancer promoting, melanogenesis, anti-inflammatory and antimicrobial actions. β-Ionone mediates these effects via activation of olfactory receptor (OR51E2) and regulation of the activity or expression of cell cycle regulatory proteins, pro-apoptotic and anti-apoptotic proteins, HMG-CoA reductase and pro-inflammatory mediators. α-Ionone and β-ionone derivatives exhibit anti-inflammatory, antimicrobial and anticancer effects, however the corresponding structure activity relationships are still inconclusive. Overall, data demonstrates that ionone is a promising scaffold for cancer, inflammation and infectious disease research and thus is more than simply a violet’s fragrance.     

Direct Imaging of Atomically Dispersed Molybdenum that Enables Location of Aluminum in the Framework of Zeolite ZSM-5

Integrated differential phase-contrast scanning transmission electron microscopy (iDPC-STEM) is capable of directly probing guest molecules in zeolites, owing to its sufficient and interpretable image contrast for both heavy and light elements under low-dose conditions. This unique ability is demonstrated by imaging volatile organic compounds adsorbed in zeolite Silicalite-1; iDPC-STEM was then used to investigate molybdenum supported on various zeolites including Silicalite-1, ZSM-5, and mordenite. Isolated single-Mo clusters were observed in the micropores of ZSM-5, demonstrating the crucial role of framework Al in driving Mo atomically dispersed into the micropores. Importantly, the specific one-to-one Mo-Al interaction makes it possible to locate Al atoms, that is, catalytic active sites, in the ZSM-5 framework from the images, according to the positions of Mo atoms in the micropores.     

Novel copolymers of styrene. 6. Some oxy ring-disubstituted propyl 2-cyano-3-phenyl-2-propenoates

Novel trisubstituted ethylenes, oxy ring-disubstituted propyl 2-cyano-3-phenyl-2-propenoates, RPhCH = C(CN)CO₂C₃H₇ (where R is 4-methoxy-2-methyl, 4-methoxy-3-methyl, 3-ethoxy-4-methoxy, 3,4-dibenzyloxy, 3-benzyloxy-4-methoxy, 4-benzyloxy-3-methoxy) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and propyl cyanoacetate and characterized by CHN elemental analysis, IR, ¹H- and ¹³C-NMR. All the ethylenes were copolymerized with styrene (M₁) in solution with radical initiation (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C-NMR, GPC, DSC, and TGA. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (3–22% wt.), which then decomposed in the 500–800°C range.     

In situ Generation of Molybdenum Carbide in Zeolite for Methane Dehydroaromatization

Kinetics and Catalysis - Molybdenum-modified zeolite is the benchmark catalyst reported to date as an effective bi-functional catalyst for methane direct conversion to aromatics and hydrogen...     

Rapid and sensitive HPLC–MS/MS method for the quantification of dopamine,GABA, serotonin,glutamine and glutamate in rat brain regions after exposure to tobacco cigarettes

Tobacco smoking is a preventable main cause of fatal diseases. Accurate measurements of the effects it has on neurotransmitters are essential in developing new strategies for smoking cessation. Moreover, measurements of neurotransmitter levels can aid in developing drugs that counteract the effects of smoking. The aim of this study is to develop and validate a fast, simultaneous and sensitive method for measuring the levels of neurotransmitters in rat brain after the exposure of tobacco cigarettes. The selected neurotransmitters include dopamine, GABA, serotonin, glutamine and glutamate. The method is based on high-performance liquid chromatography–tandem mass spectrometry. Chromatographic separation was achieved within 3 min using a Zorbax SB C₁₈ column (3.0 × 100 mm, 1.8 μm particle size). The mobile phase consisted of HPLC-grade water and acetonitrile each containing 0.3% heptafluorobutyric acid and 0.5% formic acid at gradient conditions. The linear range was 0.015–0.07, 825–7,218, 140–520, 63.42–160.75 and 38.25 × 10³ to 110.35 × 10³ ng/ml for dopamine, GABA, serotonin, glutamine and glutamate, respectively. Inter- and intra-run accuracy were in the range 97.82–103.37% with a precision (CV%) of ≤0.90%. The results revealed that 4 weeks of cigarette exposure significantly increased neurotransmitter levels after exposure to tobacco cigarettes in various brain regions, including the hippocampus and the amygdala. This increase in neurotransmitters levels may in turn activate the nicotine dependence pathway.