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Journal of Breath Research Jul 2024Preservation of the breath sample integrity during storage and transport is one of biggest challenges in off-line exhaled breath gas analysis. In this context, adsorbent...
Preservation of the breath sample integrity during storage and transport is one of biggest challenges in off-line exhaled breath gas analysis. In this context, adsorbent tubes are frequently used as storage containers for use with analytical methods employing gas chromatography with mass spectrometric detection. The key objective of this short communication is to provide data on the recovery of selected breath volatiles from Tenax® TA adsorbent tubes that were stored at -80 C for up to 90 days. For this purpose, an Owlstone Medical's ReCIVA® Breath Sampler was used for exhaled breath collection. The following fifteen compounds, selected to cover a range of chemical properties, were monitored for their stability: isoprene, n-heptane, n-nonane, toluene, p-cymene, allyl methyl sulfide, 1-(methylthio)-propane, 1-(methylthio)-1-propene, -pinene, DL-limonene, β-pinene, -terpinene, 2-pentanone, acetoin and 2,3 butanedione. All compounds but one (acetoin) were found to be stable during the first 4 weeks of storage (recovery within 2×RSD). Furthermore, n-nonane was stable during the whole of the investigated period.
PubMed: 38955168
DOI: 10.1088/1752-7163/ad5dee -
Chemical Communications (Cambridge,... Jul 2024O-Assisted oxidative dehydrogenation of propane (O-ODHP) could convert abundant shale gas into propylene as an important chemical raw material, meaning O-ODHP has... (Review)
Review
O-Assisted oxidative dehydrogenation of propane (O-ODHP) could convert abundant shale gas into propylene as an important chemical raw material, meaning O-ODHP has practical significance. Thermodynamically, high temperature is beneficial for O-ODHP; however, high reaction temperature always causes the overoxidation of propylene, leading to a decline in its selectivity. In this regard, it is crucial to achieve low temperatures while maintaining high efficiency and selectivity during O-ODHP. The use of catalytic technology provides more opportunities for achieving high-efficiency O-ODHP under mild conditions. Up to now, many kinds of catalytic systems have been elaborately designed, including transition metal oxide catalysts (such as vanadium-based catalysts, molybdenum-based catalysts, ), transition metal-based catalysts (such as Pt nanoclusters), rare earth metal oxide catalysts (especially CeO related catalysts), and non-metallic catalysts (BN, other B-containing catalysts, and C-based catalysts). In this review, we have summarized the development progress of mainstream catalysts in O-ODHP, aiming at providing a clear picture to the catalysis community and advancing this research field further.
PubMed: 38949820
DOI: 10.1039/d4cc01948b -
MLife Jun 2024is a hyperthermophilic crenarchaeon that produces 1-butanol as an end product. A thermostable alcohol dehydrogenase (ADH) must be present in to act as the key enzyme...
is a hyperthermophilic crenarchaeon that produces 1-butanol as an end product. A thermostable alcohol dehydrogenase (ADH) must be present in to act as the key enzyme responsible for this production; however, the gene that encodes the ADH has not yet been identified. A novel ADH, HbADH2, was purified from a cell-free extract of , and its characteristics were determined. The gene that encodes HbADH2 was demonstrated to be and annotated as a hypothetical protein in . HbADH2 was found to be a primary-secondary ADH capable of using a wide range of substrates, including butyraldehyde and butanol. Butyraldehyde had the highest specificity constant, calculated as / , with and apparent values of 8.00 ± 0.22 s and 0.59 ± 0.07 mM, respectively. The apparent values for other substrates, including ethanol, 1-propanol, 2-propanol, butanol, acetaldehyde, propanal, and acetone, were 4.36 ± 0.42, 4.69 ± 0.41, 3.74 ± 0.46, 2.44 ± 0.30, 1.27 ± 0.18, 1.55 ± 0.20, and 0.68 ± 0.04 mM, respectively. The optimal pH values for catalyzing aldehyde reduction and alcohol oxidation were 6.0 and 9.0, respectively, while the optimal temperature was higher than 90°C due to the increase in enzymatic activity from 60°C to 90°C. Based on its substrate specificity, enzyme kinetics, and thermostability, HbADH2 may be the ADH that catalyzes the production of 1-butanol in . The putative conserved motif sites for NAD(P) and iron binding were identified by aligning HbADH2 with previously characterized Fe-containing ADHs.
PubMed: 38948144
DOI: 10.1002/mlf2.12126 -
The Science of the Total Environment Jun 2024Volatile organic compounds (VOCs) are key precursors for secondary organic aerosols (SOA) and ozone, imposing severe impacts on human health and environment. Considering...
Volatile organic compounds (VOCs) are key precursors for secondary organic aerosols (SOA) and ozone, imposing severe impacts on human health and environment. Considering the massive coal consumption, coal fired power plants (CFPPs) in China are non-negligible VOCs contributors, whose emission characteristics remain inadequately understood. Here, we investigated emission characteristics of 117 VOCs by field tests in four typical CFPPs, and a latest localized CFPPs source profile was compiled by integrating literature reviews. Then speciated-VOCs emission inventories for 2018-2022 were established based on dynamic emission factors and unit-level activity data. The results suggested that oxygenated VOCs (OVOCs) constituted the dominant group (76.5 %), with propionaldehyde (32.0 %) and formaldehyde (24.5 %) being the predominant species. OVOCs (93.2 %) and aromatics (77.4 %) were identified as the primary contributors to ozone and SOA, respectively. Driven by both the rise in coal consumption and technological advancements, nationwide VOCs emissions decreased from 83,393 t in 2018 to 53,251 t in 2022. Regional disparities and varying rates of decline in provincial emissions were evident, with VOCs emissions predominantly concentrated in northern and eastern provinces. Neimenggu, Shandong, Shanxi, Jiangsu, and Guangdong were identified as the top five provinces with the highest emissions. We believe this study would be conducive to a more comprehensive understanding and effective control of VOCs emissions from CFPPs in China.
PubMed: 38945240
DOI: 10.1016/j.scitotenv.2024.174304 -
The Journal of Physical Chemistry... Jun 2024Photocatalytic oxidative dehydrogenation of propane (CH) into propene (CH) under mild conditions holds great potential in the chemical industry, but understanding how...
Photocatalytic oxidative dehydrogenation of propane (CH) into propene (CH) under mild conditions holds great potential in the chemical industry, but understanding how active species participate in CH conversion remains a significant challenge. Here, the wavelength-dependent activities of bridging oxygen (O) and the Ti-bound oxygen adatom (O) of model rutile (R) TiO(110) in CH conversion have been investigated. Under 257 and 343 nm irradiation, hole-trapped O and O can abstract the hydrogen atom of CH, forming the CHCHCH radical and CH. However, the rate of CH conversion with hole-trapped O is strongly dependent on the wavelength, primarily producing the CH radical. In the case of hole-trapped O, CH is the main product, which is nearly independent of wavelength. The differences in the wavelength-dependent activity and product selectivity are likely due to dynamic control rather than thermodynamic control. The result provides a deeper understanding of the dynamic processes involved in the conversion of light alkanes in TiO photocatalysis.
PubMed: 38940377
DOI: 10.1021/acs.jpclett.4c01035 -
Dalton Transactions (Cambridge, England... Jun 2024Palladium(II) complexes have stimulated research interest mainly due to their cytotoxicity against various cancer cell lines and their low cytotoxicity in healthy...
Palladium(II) complexes have stimulated research interest mainly due to their cytotoxicity against various cancer cell lines and their low cytotoxicity in healthy cells. Thus, in this work, we combined Pd(II)/phosphine systems with the natural product curcumin as a ligand, obtaining a series of complexes, [Pd(cur)(PPh)]PF (A1), [Pd(cur)(dppe)]PF (A2), [Pd(cur)(dppp)]PF (A3), [Pd(cur)(dppb)]PF (A4) and [Pd(cur)(dppf)]PF (A5), where dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,3-bis(diphenylphosphino)propane, dppb = 1,4-bis(diphenylphosphino)butane, and dppf = 1,1'-bis(diphenylphosphino)ferrocene (P-P), which were characterized by elemental analysis, molar conductivity analysis, and mass, NMR (H, C, P{H}), UV-vis, and IR spectroscopies, and four of them (A1, A2, A4, and A5) by X-ray crystallography. The cell viability of the complexes A1-A5, cisplatin, and the free ligand curcumin against MDA-MB-231 (human triple-negative breast tumor cells), SK-BR-3 (human breast tumor cells), A549 (human lung tumor cells), MRC-5 (non-tumor human lung cells), A2780 (human ovarian carcinoma cells), and A2780cis (cisplatin-resistant human ovarian carcinoma cells), was evaluated by the MTT colorimetric assay. For the tumor cell lines tested, the complexes showed good anticancer activities. The results showed that in general the complexes had lower IC values than free curcumin and the precursors [PdCl(P-P)]. IC results obtained for the A1-A5 complexes, in the MCF-7 cell line, are similar to those that had already been observed for some Pd/bipy/curcumin complexes. In the MDA-MB-231 cell line, complexes A1 and A5 stood out, with their lowest IC values, around 5 μmol L, and the complexes appeared to be more active (lower IC values) against the ovarian cell lines. Complex A1 was 23 and 22-fold more cytotoxic than cisplatin, against the A2780 and A2780cis cells, respectively. The complex A1 was studied on A2780cis cells and it was found that this complex inhibits colony formation and induces cell cycle arrest in the sub-G1 phase in a concentration-dependent manner and leads to cell death by apoptosis. The DCFDA assay revealed a potent ROS induction for complex A1.
PubMed: 38938129
DOI: 10.1039/d4dt01045k -
Materials (Basel, Switzerland) Jun 2024The robust electronegativity of the [BO] structure enables the extraction of electrons from adjacent metals, offering a strategy for modulating oxygen activation in...
The robust electronegativity of the [BO] structure enables the extraction of electrons from adjacent metals, offering a strategy for modulating oxygen activation in propane oxidative dehydrogenation. Metals (Ni 1.91, Al 1.5, and Ca 1.0) with varying electronegativities were employed to engineer borate catalysts. Metals in borate lacked intrinsic catalytic activity for propane conversion; instead, they modulated [BO] group reactivity through adjustments in electron density. Moderate metal electronegativity favored propane oxidative dehydrogenation to propylene, whereas excessively low electronegativity led to propane overoxidation to carbon dioxide. Aluminum, with moderate electronegativity, demonstrated optimal performance. Catalyst AlBOx-1000 achieved a propane conversion of 47.5%, with the highest propylene yield of 30.89% at 550 °C, and a total olefin yield of 51.51% with a 58.92% propane conversion at 575 °C. Furthermore, the stable borate structure prevents boron element loss in harsh conditions and holds promise for industrial-scale catalysis.
PubMed: 38930237
DOI: 10.3390/ma17122868 -
Angewandte Chemie (International Ed. in... Jun 2024Small-molecule receptors are increasingly employed to probe various functional groups for (bio)chemical analysis. However, differentiation of polyfunctional analogs...
Small-molecule receptors are increasingly employed to probe various functional groups for (bio)chemical analysis. However, differentiation of polyfunctional analogs sharing multiple functional groups remains challenging for conventional mono- and bidentate receptors because their insufficient number of binding sites limits interactions with the least reactive yet property-determining functional group. Herein, we introduce 6-thioguanine (TG) as a supramolecular receptor for unique tridentate receptor-analyte complexation,achieving ≥ 95% identification accuracy among 16 polyfunctional analogs across three scenarios: glycerol derivatives, disubstituted propanes, and vicinal diols. Crucially, we demonstrate distinct spectral changes induced by the tridentate interaction between TG's three anchoring points and all the analyte's functional groups, even the least reactive ones. Notably, H-bond networks formed in the TG-analyte complexes demonstrate additive effect in binding strength originating from good bond linearity, cooperativity, and resonance, thus strengthens complexation events and amplifies the differences in spectral changes induced among analytes. It also enhances spectral consistency by selectively form a sole configuration that is stronger than the respective analyte-analyte interaction. Finally, we achieve 95.4% accuracy for multiplex identification of a mixture consisting of multiple polyfunctional analogs. We envisage that extension to other multidentate non-covalent interactions enables the development of interference-free small molecule-based sensors for various (bio)chemical analysis applications.
PubMed: 38925600
DOI: 10.1002/anie.202410815 -
Nanomaterials (Basel, Switzerland) Jun 2024Carbon deposits consisting of vertically oriented multilayer graphene sheets on metallic foils represent an interesting alternative to activated carbon in electrical and...
Carbon deposits consisting of vertically oriented multilayer graphene sheets on metallic foils represent an interesting alternative to activated carbon in electrical and electrochemical devices such as super-capacitors because of the superior electrical conductivity of graphene and huge surface-mass ratio. The graphene sheets were deposited on cobalt foils by plasma-enhanced chemical vapor deposition using propane as the carbon precursor. Plasma was sustained by an inductively coupled radiofrequency discharge in the H mode at a power of 500 W and a propane pressure of 17 Pa. The precursor effectively dissociated in plasma conditions and enabled the growth of porous films consisting of multilayer graphene sheets. The deposition rate varied with time and peaked at 100 nm/s. The evolution of surface wettability was determined by the sessile drop method. The untreated substrates were moderately hydrophobic at a water contact angle of about 110°. The contact angle dropped to about 50° after plasma treatment for less than a second and increased monotonously thereafter. The maximal contact angle of 130° appeared at a treatment time of about 30 s. Thereafter, it slowly decreased, with a prolonged deposition time. The evolution of the wettability was explained by surface composition and morphology. A brief treatment with oxygen plasma enabled a super-hydrophilic surface finish of the films consisting of multilayer graphene sheets.
PubMed: 38921899
DOI: 10.3390/nano14121023 -
Acta Chimica Slovenica May 2024Three new copper(II) complexes, [CuClL] (1), [CuBrL]n (2) and [CuL(NCS)]n (3), derived from the Schiff base 2,4-dichloro-6-((2-pyrrolidin-1-ylethylimino)methyl)phenol...
Three new copper(II) complexes, [CuClL] (1), [CuBrL]n (2) and [CuL(NCS)]n (3), derived from the Schiff base 2,4-dichloro-6-((2-pyrrolidin-1-ylethylimino)methyl)phenol (HL) have been prepared and characterized by spectroscopy methods, as well as single crystal X-ray determination. The Cu atom in complex 1 is in square planar coordination, and those in complexes 2 and 3 are in square pyramidal coordination. The Schiff base ligand coordinates to the Cu atoms through phenolate oxygen, imino nitrogen and pyrrolidine nitrogen. The antibacterial activities of the Schiff base and the three copper complexes have been assayed on the bacteria Staphylococcus aureus and Escherichia coli, and the yeast Candida parapsilosis.
PubMed: 38919098
DOI: 10.17344/acsi.2024.8707