Single-crystal oxygen-rich bismuth oxybromide nanosheets with highly exposed defective {10-1} facets for the selective oxidation of toluene under blue LED irradiation

Reactive radicals are crucial for activating inert and low-polarity C(sp3)-H bonds for the fabrication of high value-added products. Herein, novel single-crystal oxygen-rich bismuth oxybromide nanosheets (Bi4O5Br2 SCNs) with more than 85 % {10-1} facets exposure and oxygen defects were synthesized via a facile solvothermal route. The Bi4O5Br2 SCNs demonstrated excellent photocatalytic performance in the selective oxidation of toluene under blue light. The yield of benzaldehyde was 1876.66 μmol g-1 h-1, with a selectivity of approximately 90 %. Compared to that of polycrystalline Bi4O5Br2 nanosheets (Bi4O5Br2 PCNs), the activity of Bi4O5Br2 SCNs exhibit a 21-fold increase. Experimental studies and density functional theory (DFT) calculations have demonstrated that the defect Bi4O5Br2 (10-1) facets exhibits exceptional adsorption properties for O2 molecules. In addition, the single-crystal structure in the presence of surface defects significantly increases the separation and transport of photogenerated carriers, resulting in the effective activation of adsorbed O2 into superoxide radicals (•O2-). Subsequently, the positively charged phenylmethyl H is readily linked to the negatively charged superoxide radical anion, thereby activating the CH bond. This study offers a fresh perspective and valuable insights into the development of efficient molecular oxygen-activated photocatalysts and their application in the selective catalytic conversion of aromatic C(sp3)-H bonds.

dorsalis through olfaction

The Oriental fruit fly, Bactrocera dorsalis, is a significant pest that damages a variety of fruit crops. The effectiveness of chemical pesticides against such pests is limited, raising concerns about pesticide residues and resistance. Proteins naturally attract B. dorsalis and have led to the development of a management strategy known as protein bait attractant technology (BAT). Although the attraction of protein sources to B. dorsalis is well-documented, the biologically active components within these sources are not fully understood. This study employed analytical chemistry, behavioral tests, and electrophysiological techniques to investigate the behaviorally active components of beer yeast protein powder (BYPD), aiming to provide a basis for improving and developing protein baits. An olfactory trap assay confirmed the attractiveness of BYPD, and five components with high abundance were identified from its headspace volatiles using GC-MS. These components included ethanol, isoamyl alcohol, ethyl decanoate, benzaldehyde, and phenylethyl alcohol. Mixtures of these five components demonstrated significant attraction to B. dorsalis adults, with benzaldehyde identified as a potential key component. The attractiveness of benzaldehyde required a relatively large dose, and it was most attractive to adults that had been starved from dusk until the following morning. Attraction of adult flies to benzaldehyde appeared mainly mediated by inputs from olfactory receptors. While EAG data supports that ionotropic receptors could influence the detection of benzaldehyde in female adults, they did not affect female behavior towards benzaldehyde. These findings indicate that benzaldehyde is an important behaviorally active component in BYPD and offer insights for developing novel protein lures to control B. dorsalis in an environmentally friendly manner.

Streamlined synthesis of iron and cobalt loaded MCM-48: High-performance heterogeneous catalysts for selective liquid-phase oxidation of toluene to benzaldehyde

Hydrothermal synthesis of MCM-48 molecular sieves featuring the incorporation of both iron and cobalt with Si/M ratios of 20, 40 and 80 (where M represents either iron or cobalt) was performed using tetraethyl orthosilicate as the silica source and cetyltrimethylammonium bromide as a template. To gain a comprehensive understanding of the synthesized materials, these were thoroughly characterized using various techniques, including XRD, XPS, UV-Vis (DRS), FT-IR, N2 adsorption-desorption analysis, SEM with EDX, TEM, TGA and NH3-TPD analysis. XRD analysis revealed the presence of well-ordered MCM-48 structure in the metal-incorporated materials, while XPS and UV-Vis DRS confirmed the successful partial incorporation of metal ions precisely in their desired tetrahedral coordination within the framework. To assess their catalytic performance, we studied the activity and selectivity of these catalysts in liquid phase oxidation of toluene using tert-butyl hydroperoxide as the oxidant. Under optimized conditions, employing a 6% (w/w) Fe-MCM-48 (40) catalyst and maintaining a toluene to oxidant molar ratio of 1:3 at 353 K in a solvent-free environment for 8 h, the oxidation reaction resulted in the formation of benzaldehyde (88.1%) as the major product and benzyl alcohol (11.9%) as the minor product.

Systematic engineering enables efficient biosynthesis of L-phenylalanine in E. coli from inexpensive aromatic precursors

BACKGROUND

L-phenylalanine is an essential amino acid with various promising applications. The microbial pathway for L-phenylalanine synthesis from glucose in wild strains involves lengthy steps and stringent feedback regulation that limits the production yield. It is attractive to find other candidates, which could be used to establish a succinct and cost-effective pathway for L-phenylalanine production. Here, we developed an artificial bioconversion process to synthesize L-phenylalanine from inexpensive aromatic precursors (benzaldehyde or benzyl alcohol). In particular, this work opens the possibility of L-phenylalanine production from benzyl alcohol in a cofactor self-sufficient system without any addition of reductant.

RESULTS

The engineered L-phenylalanine biosynthesis pathway comprises two modules: in the first module, aromatic precursors and glycine were converted into phenylpyruvate, the key precursor for L-phenylalanine. The highly active enzyme combination was natural threonine aldolase LtaEP.p and threonine dehydratase A8HB.t, which could produce phenylpyruvate in a titer of 4.3 g/L. Overexpression of gene ridA could further increase phenylpyruvate production by 16.3%, reaching up to 5 g/L. The second module catalyzed phenylpyruvate to L-phenylalanine, and the conversion rate of phenylpyruvate was up to 93% by co-expressing PheDH and FDHV120S. Then, the engineered E. coli containing these two modules could produce L-phenylalanine from benzaldehyde with a conversion rate of 69%. Finally, we expanded the aromatic precursors to produce L-phenylalanine from benzyl alcohol, and firstly constructed the cofactor self-sufficient biosynthetic pathway to synthesize L-phenylalanine without any additional reductant such as formate.

CONCLUSION

Systematical bioconversion processes have been designed and constructed, which could provide a potential bio-based strategy for the production of high-value L-phenylalanine from low-cost starting materials aromatic precursors.

Protective effect of benzaldehyde combined with albendazole against brain injury induced by Angiostrongylus cantonensis infection in mice

Angiostrongylus cantonensis, also known as rat lungworm, is an important food-borne zoonotic parasite that causes severe neuropathological damage and symptoms, including eosinophilic meningitis and eosinophilic meningoencephalitis, in humans. At present, the therapeutic strategy for cerebral angiostrongyliasis remains controversial. Benzaldehyde, an important bioactive constituent of Gastrodia elata (Tianma), reduces oxidative stress by inhibiting the production of reactive oxygen species. This study aimed to evaluate the therapeutic effect of benzaldehyde in combination with albendazole on angiostrongyliasis in animal models. First, the data from body weight monitoring and behavioural analyses demonstrated that benzaldehyde improved body weight and cognitive function changes after A. cantonensis infection. Next, blood‒brain barrier breakdown and pathological changes were reduced after benzaldehyde and albendazole treatment in BALB/c mice infected with A. cantonensis. Subsequently, four RNA-seq datasets were established from mouse brains that had undergone different treatments: normal, infection, infection + albendazole, and infection + albendazole + 3-hydroxybenzaldehyde groups. Ultimately, benzaldehyde was found to regulate cell apoptosis, oxidative stress and Sonic Hedgehog signalling in mouse brains infected with A. cantonensis. This study evaluated the therapeutic effect of benzaldehyde on angiostrongyliasis, and provided a potential therapeutic strategy for human angiostrongyliasis in the clinical setting. Moreover, the molecular mechanism of benzaldehyde in mouse brains infected with A. cantonensis was elucidated.

Functionalization of chitosan biopolymer with SiO2 nanoparticles and benzaldehyde via hydrothermal process for acid red 88 dye adsorption: Box-Behnken design optimization

An effective hydrothermally prepared chitosan-benzaldehyde/SiO2 adsorbent (CTA-BZA/SiO2) employed functionalization of a CTA biopolymer with SiO2 nanoparticles and BZA. CTA-BZA/SiO2 is an adsorbent that was utilized for the adsorption of an acidic dye (acid red 88, AR88) from synthetic wastewater. The fundamental adsorption variables (A: CTA-BZA/SiO2 dosage (0.02-0.1 g); B: pH (4-10); and C: duration (10-60)) were optimized via the Box-Behnken design (BBD). The Langmuir and Freundlich isotherms (coefficients of determination R2 = 0.99) agreed well with empirical data of AR88 adsorption by CTA-BZA/SiO2. The pseudo-first-order model showed reasonable agreement with the kinetic data of AR88 adsorption by CTA-BZA/SiO2. The maximal AR88 adsorption capacity (qmax) for CTA-BZA/SiO2 was identified to be 252.4 mg/g. The electrostatic attractions between both the positively charged CTA-BZA/SiO2 adsorbent and the AR88 anions, plus the n-π, π-π, and H-bond interactions contribute to the favourable adsorption process. This study reveals that CTA-BZA/SiO2 has the capacity to be a suitable adsorbent for the removal of a wider range of organic dyes from industrial effluents.

Fluorosensing of benzaldehydes by CuI-graphene: A spectroscopy, thermodynamics and docking supported phenomenon

Benzaldehyde and 4-methyl benzaldehyde constitute a major part of the harmful volatile organic compounds (VOCs) found in the environment. Hence, rapid and selective detection of benzaldehyde derivatives are required to minimize the environmental degradation as well as the potential hazards on human health. In this study, the surface of the graphene nanoplatelets were functionalized with CuI nanoparticles for specific and selective detection of benzaldehyde derivatives by fluorescence spectroscopy. CuI-Gr nanoparticles exhibited higher efficiency towards the detection of benzaldehyde derivatives as compared to pristine CuI nanoparticles with detection limit (LOD) 2 ppm and 6 ppm for benzaldehyde and 4-methyl benzaldehyde respectively in aqueous medium. The LOD values for the detection of benzaldehyde and 4-methyl benzaldehyde by pristine CuI nanoparticles were poor and found to be 11 ppm and 15 ppm respectively. Fluorescence intensity of CuI-Gr nanoparticles were found to be quenched with increasing concentration (0-0.01 mg/mL) of the benzaldehyde and 4-methyl benzaldehyde. This novel graphene-based sensor was also found to be highly selective for the benzaldehyde derivatives as no changes in signal were detected in presence of other VOCs like formaldehyde and acetaldehyde.

Chronic oral nicotine exposure decreases aversive taste of nicotine, increases nicotine withdrawal and reinstatement, but cherry flavor does not alter nicotine's effects in adolescent rats

Although e-cigarette use among youth is recognized as an epidemic, there is limited understanding regarding nicotine's orosensory and chronic use effects in youth, and how fruit e-cigarette flavorings may influence nicotine's effects. We aimed to characterize the orosensory and chronic use effects of nicotine in adolescent rats. We also determined the acute and chronic effects of benzaldehyde, a cherry/berry/almond flavoring, on nicotine's taste, consumption, withdrawal, and reinstatement. Rats were examined for their acute taste responses to the different nicotine concentrations. The effects of chronic exposure on nicotine's taste, withdrawal, and reinstatement were also determined. In addition, impact of benzaldehyde on these nicotine use behaviors was evaluated. While taste responses to low nicotine concentrations did not differ from water, high nicotine concentrations induced aversion. Aversive responses to nicotine that were observed in naïve animals vanished after chronic nicotine exposure, indicating the development of tolerance to nicotine's aversive taste. Additionally, nicotine abstinence after chronic exposure induced withdrawal. Following abstinence, animals reinstated nicotine use. Further, animals showed higher preference to nicotine after reinstatement, compared to preference values before nicotine withdrawal. Benzaldehyde did not alter nicotine's taste reactivity, withdrawal, and reinstatement experiments. Some sex differences were found in benzaldehyde's taste response and choice behavior experiments.

Coffee-waste templated CeOx/TiO2 nanostructured materials for selective photocatalytic oxidations

An environmentally friendly solvent-free approach was tested using spent coffee as a biomass sacrificial template for the preparation of TiO₂ modified with CeO_x. The use of coffee as a template pursues the preparation of a nanostructured heterojunction without the need for a solvent. Two variables were optimized in the synthesis process, i.e. calcination temperature and proportion of CeO_x. Firstly, bare coffee-template titania was prepared to explore the effect of the calcination temperature, within 500-650 °C. The anatase phase was obtained up to 600 °C. Higher temperatures, i.e. 650 °C, led to the appearance of rutile (10%) and efficient removal of the sacrificial agent (0.6% residue). The maximum photocatalytic activity in terms of conversion, in the oxidation of benzyl alcohol, was achieved employing the bare coffee-template TiO₂ at 650 °C, and it was found comparable to the benchmarked P25. The incorporation of ceria in the solvent-free approach considerably improved photocatalytic benzaldehyde production. No changes in the XRD pattern of TiO₂ were appreciated in the presence of ceria due to the low amount added, within 1.5-6.0%, confirmed by XPS as superficial Ce³⁺/Ce⁴⁺. The UV-visible absorption spectra were considerably redshifted in the presence of Ce, reducing the bandgap values of bare titania. An optimum amount of ceria in the structure within 3-0% was found. In this case, the selectivity towards benzaldehyde was ca. 75%, 3 times higher than the selectivity value registered for the benchmarked P25 or the bare prepared TiO₂.

Revisiting the protocol for determining submicromolar concentrations of ozone in the water treated by advanced oxidation processes

Ozone is formed at submicromolar concentrations from photolysis of many oxyanions and oxidants in water and contributes importantly to the degradation of emerging contaminants and inactivation of pathogenic microorganisms in the natural and engineered aquatic systems. In this study, we identified and discussed the critical limitations of the commonly-used protocols using cinnamic acid (CNA) as a probe compound to determine the submicromolar-level ozone and proposed a modified protocol that overcomes those limitations. Our experimental investigation demonstrated that the radicals (e.g., HO^•) formed from photolysis of oxyanions and oxidants, other than ozone, could also oxidize CNA and form benzaldehyde, resulting in the overestimation of ozone concentrations by using the commonly-used protocols. Moreover, the benzaldehyde formed from ozone-CNA reactions could be degraded by the radicals, leading to the underestimation of ozone concentrations by using the commonly-used protocols. A new protocol with high accuracy and precision was proposed and the rationales for each operational step of the new protocol were explained in detail and supported with justifications. The new protocol was compared with two commonly-used protocols in determining the concentration of ozone in the same water sample treated by the UV/chlorine process at three different UV wavelengths. The wavelength-dependent overestimation/underestimation of the ozone concentrations by using the two commonly-used protocols was well demonstrated and explained by the overlooked interferences of radicals in the protocols.

Facile preparation of ultrafine Pd nanoparticles anchored on covalent triazine frameworks catalysts for efficient N-alkylation

The fabrication of stable and efficient catalysts for green and economic catalytic transformation is significant. Here, highly stable covalent triazine frameworks (CTF-1) were used as the supporting material for anchoring ultrafine Pd nanoparticles (NPs) via a facile impregnation process and a one-pot calcination-reduction strategy. The widespread dispersion of ultrafine Pd NPs was a result of the abundant high nitrogen-content triazine groups of CTF-1 that endowed the catalyst Pd@CTF-1 with high catalytic activity. The catalytic performance of Pd@CTF-1 was demonstrated by the one-pot N-alkylation of benzaldehyde with aniline (or nitrobenzene) under mild reaction conditions, and Pd@CTF-1 exhibited a wide range of general applicability for N-alkylation reactions. The reaction mechanism for the N-alkylation reaction was also studied in detail. In addition, the Pd@CTF-1 catalyst exhibited high thermal and chemical stability, maintaining good catalytic efficiency after multiple reaction cycles. This study provides new insights for the fabrication of organic supporting materials with highly dispersed active catalytic sites that can lead to excellent catalytic performance for efficient, economical, and green reactions.

Efficacy of collars with allomones on dogs to control Rhipicephalus sanguineus sensu lato infestations under field conditions

Benzaldehyde and 2-hexanone are allomones produced by beagle dogs that reduce infestation by Rhipicephalus sanguineus sensu lato on these animals and on susceptible dogs which artificially release these repellents. These observations were obtained in previous laboratory tests or artificial infestations of susceptible dogs under controlled conditions. Here we evaluated the efficacy of collars delivering these repellents for suppressing the loads of R. sanguineus s.l. on naturally infested mixed-breed dogs under field conditions. Thirty dogs naturally infested with R. sanguineus s.l. were separated into two groups with 15 dogs each. The dogs from the treatment group received the collars with slow-release formulations of the allomones, and the dogs from the control group received collars without such compounds. Collar effectiveness tests were carried out over 30 days. All ticks found were removed from each dog, identified, and counted every collection day. The density of the different life stages of R. sanguineus s.l. varied greatly between groups and across evaluation times. Adult ticks were the stage most abundant and prevalent on infested dogs. The counts for larvae, nymphs and adults were similar between the control and the treatment groups within each tick collection day. Conversely, when we considered the total number of ticks over 30 days and gathered all life stages collected in the same animal, the dogs from the control group had significantly higher loads (35.3 ± 4.27) of ticks than the dogs from the treatment group (21.8 ± 2.96) (P < 0.01). In addition, the efficacy of treatment with repellent collars was high for adult ticks (30.8%) but was extremely low for reducing larval or nymphal infestation (0 or 2.6%, respectively). The present study demonstrates, for the first time, the efficacy of these volatile compounds on naturally infested dogs under field conditions. The development of a technologically enhanced device for slow release of the allomones tested here can be an advantageous alternative for reducing R. sanguineus s.l. infestation on dogs in residential environments.

Chemically-mediated colonization of black cherry by the peach bark beetle, Phloeotribus liminaris

The peach bark beetle (Phloeotribus liminaris Harris, PBB) affects the health, quality, and value of black cherry (Prunus serotina Ehrh.) within the Central Hardwoods Forest Region of North America. When colonized by adult beetles, black cherry trees produce a defensive exudate, or 'gum', staining the wood and decreasing its value up to 90%. Current management tactics are inadequate to avoid extensive damage to most veneer-sized black cherry in the region. We test the hypothesis that PBB colonization behavior is chemically-mediated and determine the extent to which PBB is attracted to compounds associated with wounded or PBB-infested cherry wood. Through olfactometer and field bioassays, we determined that adult PBB were attracted to cherry branches infested with female beetles. We then used dynamic headspace sampling to collect volatiles associated with wounded and infested bolts of black cherry. The volatile benzaldehyde dominated these collections and was more abundant in aerations of female-infested bolts than other odor sources. In subsequent field bioassays, we evaluated the bioactivity of benzaldehyde, as well as α-longipinene, in combination with several chemical carriers. Traps baited with benzaldehyde captured more PBB than all other treatments, irrespective of other lure components. Moreover, PBB were not attracted to traps baited solely with ethanol, a common attractant for bark beetles that colonize hardwood trees. This is the first report of benzaldehyde as an attractant for a species of bark beetle and could aid in developing semiochemical-based management tactics for this important pest.

Acetalization of glycerol and benzaldehyde to synthesize biofuel additives using SO4 2-/CeO2-ZrO2 catalyst

Synthesis of 1,3- dioxane and 1,3-dioxolane, using sulfated CeO₂–ZrO₂ catalyst for acetalization of glycerol with benzaldehyde, is the focus of present work. SO₄^2-/CeO₂–ZrO₂ catalyst was synthesized using combustion method. Experiments were carried out to analyze the effect of various solvents (n-hexane, toluene, tert-butyl alcohol, pentanol), molar ratios (1:3, 1:5, 1:7), catalyst loadings (3 wt%, 5 wt%, 9 wt %) and temperatures (80 °C, 90 °C, 100 °C) on glycerol conversion and selectivity of the products. Selectivity of 87.20% dioxolane and 12.80% dioxane was obtained at molar ratio of 1:3, 9 wt% catalyst loading and temperature of 100 °C.Strong NH₃ desorption peak from NH₃-TPD study indicated the high acidic strength of sulphated catalyst. Strong surface acidity and surface porosity (observed from TEM and SEM analysis) contributed to an enhanced activity of the catalyst for glycerol acetalization reaction. The kinetics of the reaction was studied using an elementary kinetic law. A correlation coefficient of 0.98 from the selected kinetic model proved that the rate of acetalization reaction was dependent on glycerol concentration and acetal formation was instantaneous. The study demonstrated the application of an environmentally benign, inexpensive, thermally stable, active SO₄^2-/CeO₂–ZrO₂ catalyst for glycerol acetalization reaction to synthesize 1,3-dioxolane as the desired product.

An efficient broad spectrum-driven carbon and oxygen co-doped g-C3N4 for the photodegradation of endocrine disrupting: Mechanism, degradation pathway, DFT calculation and toluene selective oxidation

In this study, a new type of carbon and oxygen co-doped g-C₃N₄ (PACN) was successfully synthesized by a one-step thermal polymerization method for the photodegradation of Bisphenol A (BPA) and selective oxidation of toluene to benzaldehyde. The degradation rate of BPA was 23.58 times higher than that of pristine g-C₃N₄ and the efficiency benzaldehyde formation rate without the need of any solvent increased to 5.43 times that of g-C₃N₄. At the same time, the band structure calculation of its simulated structure is performed by DFT, which shows that the introduction of oxygen linking band can adjust its band structure and obtain a smaller band gap. In addition, the PACN displays an enhanced photocatalytic degradation of BPA under the long wavelength (λ ≥ 550 nm) and NIR light irradiation (λ ≥ 760 nm), which indicates that the synthesized materials have a broad spectrum of photocatalytic activity. According to the results of secondary ion mass spectrometry (SIMS) and nuclear magnetic resonance spectroscopy (NMR), C atoms and O atoms were introduced into the original g-C₃N₄ skeleton. In addition, the intermediate products were detected by mass spectrometry (HPLC-MS), and the BPA degradation pathway was proposed. A feasible photocatalytic reaction mechanism was also proposed.

Association of aldehyde exposure with cardiovascular disease

The effect of aldehyde exposure on the cardiovascular system remains unclear. The objective of this study was to determine whether aldehyde exposure is associated with the prevalence of cardiovascular disease (CVD). We analyzed associations between aldehydes and CVD using data from 1962 adult participants in the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2014. Multivariable logistic regression and restricted cubic spline models were used to examine the association between aldehydes and CVD. The prevalence of CVD was 10.3%. After adjusting for confounding factors, including age, sex, education level, race, diabetes mellitus, smoking, alcohol use, hypertension, body mass index, the poverty-income ratio, physical activity, energy intake, high-density cholesterol (HDL) and low-density cholesterol (LDL), compared with the lowest quartiles, the odds ratios (ORs) with 95% confidence intervals (CIs) for CVD across the quartiles were 0.52 (0.31, 0.87), 0.73 (0.43, 1.22), and 1.13 (0.68, 1.86) for benzaldehyde and 1.48 (0.87, 2.52), 1.70 (1.01, 2.92), and 2.13 (1.19, 3.86) for isopentanaldehyde. There was no significant association between other aldehydes and CVD. The restricted cubic spline plot showed a J-curve relationship between benzaldehyde and CVD. The inflection point for the curve was found at a benzaldehyde level of 0.98 ng/ml. The ORs (95% CIs) for CVD were 0.51 (0.31, 0.86) and 1.58 (1.15, 2.17) on the left and right sides of the inflection point, respectively. Our results demonstrate a J-curve relationship between benzaldehyde and CVD. Isopentanaldehyde is positively associated with CVD. Further study is warranted to verify this association and to elucidate its underlying mechanisms.

Development and validation of a thermally regulated atmospheric simulation chamber (THALAMOS): A versatile tool to simulate atmospheric processes

Atmospheric simulation chambers, are unique tools for investigating atmospheric processes in the gas and heterogeneous phases. They can provide a controlled yet realistic environment that simulates atmospheric conditions. In the current study, a Teflon atmospheric simulation chamber of 600 L, named THALAMOS (thermally regulated atmospheric simulation chamber) has been developed and cross-validated. THALAMOS can be operated over the temperature range 233 to 373 K under both static and flow conditions. It is equipped with state of the art instrumentation (selective ion flow tube mass spectrometry (SIFT-MS), long path Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS), various analyzers) for the in-line monitoring of both reactants and products. THALAMOS was validated by measuring the rate coefficients of well documented reactions, i.e. the reaction of ethanol with OH radicals and the reaction of dichloromethane with Cl atoms, in a wide temperature range. Two different detection techniques were used in parallel, FTIR and SIFT-MS, to internally cross-validate the obtained results. The measured rate coefficients are in excellent agreement, both between each other and with the literature recommended values. Furthermore, the gas phase oxidation of toluene by Cl atoms (kinetics and product yields) was studied in the temperature range of 253 to 333 K. To the best of our knowledge, THALAMOS is a unique facility on national level and among a few smog chambers internationally that can be operated in such a wide temperature range providing the scientific community with a versatile tool to simulate both outdoor and indoor physicochemical processes.

Covalently immobilized chemically modified lysozyme as a sorbent for bacterial endotoxins (lipopolysaccharides)

Chemical modification of lysozyme was carried out using benzaldehyde and anisaldehyde. It was shown that chemical modification affects only 1-2 amino groups of the protein molecule which does not prevent further covalent immobilization of lysozyme using the remaining free amino groups. The bacteriolytic activity of lysozyme is preserved after chemical modification and after subsequent covalent immobilization. As a result of chemical modification immobilized lysozyme more effectively adsorbs bacterial lipopolysaccharides (endotoxins). Adsorption of immunoglobulin G does not increase after modification. The sorbents obtained in this work can be used for the future development of new medical material for the extracorporeal treatment of sepsis. The proposed scheme for the modification and immobilization of lysozyme can be used with various aldehydes for the preparation of sorbents with different properties.

Novel amphiphilic cellulose nanocrystals for pH-responsive Pickering emulsions

Development of a green, recyclable emulsifier for pH-responsive Pickering emulsion would be of great importance to many industries. To this end, a novel emulsifier, benzyl-polyethyleneimine modified cellulose nanocrystals (Ben-PEI-CNCs), was developed via the periodate oxidation of cellulose nanocrystals and reductive amination. Ben-PEI-CNCs possess pH-responsive amphiphilicity due to the existence of hydrophilic amino and hydrophobic benzyl groups. The Pickering emulsions stabilized by Ben-PEI-CNC2 and Ben-PEI-CNC18 are very responsive to pH changes, and adjusting the pH from 3 to 7 effectively triggers oil-water separation and emulsification. Additionally, cyclic testing establishes the robustness of this process. Overall, this study demonstrates that Ben-PEI-CNCs can promote the transition from a stable emulsion to an unstable emulsion by adjusting the pH, allowing the recovery of oil and the recycling of the emulsifier.

Functionalization of silicene and silicane with benzaldehyde

Organic functionalization of nanomaterials offers exceptional flexibility in materials design, and applications in molecular sensors and molecular electronics are expected. However, more studies should be conducted to understand the interaction between nanomaterials and organic molecules. In this work, we studied the functionalization of silicene and silicane with benzaldehyde, performing nudged elastic band calculations within density functional theory. We calculated the structural changes of the adsorption process, electronic properties of the main states, and the energetics. In silicene, the adsorption of benzaldehyde on the top site was found to be the most stable, with an adsorption energy of -0.55 eV. For silicane, the functionalization proceeds through a self-propagating reaction on a highly reactive dangling bond generated by a hydrogen atom vacancy. Benzaldehyde adsorbed on this site depicts an adsorption energy of -1.39 eV, which is larger than in bare silicene. Upon attaching, the double C=O bond breaks down turning the molecule into a highly reactive radical, which in this case, abstracts a neighboring H atom of the sheet. This process is highly achievable since the energy barrier to abstract the H atoms is 0.81 eV, whereas the one needed to desorb the molecule is 1.39 eV. After H abstraction, a new dangling bond is generated at the substrate, making a chain reaction possible to potentially form benzaldehyde monolayers. Organic functionalization is an excellent tool to engineer properties of 2D systems, and having a deeper understanding of the adsorption processes is the first step toward the development of new generation devices. Graphical abstract Benzaldehyde adsorbed on silicene and silicane.

Investigation of the evaporation behavior of aroma compounds in e-cigarettes

The aim of this work was to evaluate the evaporation behavior of certain aroma compounds found in e-liquids. Since an e-liquid is evaporated, the aroma present can reach the lungs and could be absorbed into the body which may have long-term health effects above critical concentrations. Due to a lack in regulations, the sort and concentration of the compounds in sold e-liquids can vary. To capture the aroma compounds in the vapor, a smoking machine was developed. The resulting data represent the amount of aroma reaching the consumers' lungs. The influence of the e-cigarette temperature, ranging from 100 to 315 °C, on the evaporation of benzaldehyde, estragole, and different terpenoids was examined. Additionally, the effect of the liquid base composition on the amount of aroma in the vapor was compared using the analysis of variances. The influence of high temperature, the type of e-cigarette, and the atomizer coil material, which could lead to oxidation of limonene and linalool in the vapor, is shown here.

Investigation of the evaporation behavior of aroma compounds in e-cigarettes

The aim of this work was to evaluate the evaporation behavior of certain aroma compounds found in e-liquids. Since an e-liquid is evaporated, the aroma present can reach the lungs and could be absorbed into the body which may have long-term health effects above critical concentrations. Due to a lack in regulations, the sort and concentration of the compounds in sold e-liquids can vary. To capture the aroma compounds in the vapor, a smoking machine was developed. The resulting data represent the amount of aroma reaching the consumers’ lungs. The influence of the e-cigarette temperature, ranging from 100 to 315 °C, on the evaporation of benzaldehyde, estragole, and different terpenoids was examined. Additionally, the effect of the liquid base composition on the amount of aroma in the vapor was compared using the analysis of variances. The influence of high temperature, the type of e-cigarette, and the atomizer coil material, which could lead to oxidation of limonene and linalool in the vapor, is shown here.

Proteomic changes in Arthrobotrys oligospora conidia in response to benzaldehyde-induced fungistatic stress

Soil fungistasis limits the effect of fungal agents designed to control plant-parasitic nematodes. Benzaldehyde is a fungistatic factor produced by soil microorganisms that can suppress conidial germination, but the molecular mechanism of this suppression is unknown. In this study, three conidial proteomes of Arthrobotrys oligospora ATCC24927, a nematode-trapping fungus, were obtained, quantified, and compared. Under benzaldehyde fungistatic stress, conidial protein expression profile changed significantly. Screening with a twofold selection criterion revealed 164 up-regulated and 110 down-regulated proteins. 17 proteins related to protein translation were down-regulated and gene transcription analysis suggested that the repression of proteins translation might be one mechanism by which benzaldehyde inhibites conidial germination. Benzaldehyde also resulted in the down-regulation of respiratory chain proteins and mitochondrial processes, as well as the repression of conidial DNA synthesis. In addition, the conidia up-regulated several proteins that enable it to resist benzaldehyde-induced fungistatis, and this was confirmed by a functional assessment of two knockout mutants. This study reveals putative mechanisms by which benzaldehyde causes fungistasis as well as the proteomic response of conidia to benzaldehyde. SIGNIFICANCE: Soil fungistasis limits the effect of fungal agents designed to control plant-parasitic nematodes. Benzaldehyde is one of fungistatic factors produced by soil microorganisms that can suppress conidial germination. In this study, we found that conidial protein expression profile changed significantly under benzaldehyde fungistatic stress. This research revealed new mechanistic data that describe how benzaldehyde is responsible for fungiststis by inhibiting conidial germination. Moreover, we also found that conidia can resist benzaldehyde by up-regulating proteins such as benzaldehyde dehydrogenase and heat shock proteins. This study also showed that proteomics methods play important roles in addressing soil fungistatic mechanisms.

Thermo-acoustic and FTIR studies on binary liquids mixture of ethyl oleate and benzaldehyde at 303.15 to 318.15 K

Ultrasonic velocity, density and viscosity of two liquid mixtures ethyl oleate with benzaldehyde have been determined at various temperatures in the range of 303.15 to 318.15 K. The ultrasonic velocity, viscosity and density data are used to estimate adiabatic compressibility, free length, molar volume and free volume along with their excess values. The observed variations of the said parameters with concentration and temperature are discussed in terms of the intermolecular interactions between the unlike molecules of the binary mixtures. FT-IR spectra confirm the expected interactions.

Palladium Catalyzed meta-C-H Functionalization of Masked Aromatic Aldehydes

Palladium catalyzed meta-C-H functionalization enabled by transient mediators has the potential to extend the utility of directed ortho-C-H functionalization to remote positions. However, there have been no reports of palladium catalyzed meta-C-H functionalization of aromatic aldehyde derivatives, which are highly versatile intermediates in organic synthesis. Herein we report the development of a directing group that, in the presence of a norbornene derived mediator and an appropriate pyridone ligand, allows palladium catalyzed meta-C-H functionalization of masked aromatic aldehydes. Mechanistic insight regarding the impact of the directing group length on this catalysis is also discussed.

Solvo-thermal synthesis of a unique alkaline earth-transition Ba-Cd micro-porous coordination framework as hetero-metallic luminescent sensor for Cu2+ and real-time detection of benzaldehyde

In this work a unique hetero-metallic alkaline earth-transition Ba-Cd luminescent micro-porous metal-organic framework {[BaCd(μ₆-tp)_1.5(μ₂-Cl)(H₂O) (DMF)₂]·0.75H₂O}_n (H₂tp=terephthalic acid) (1) has been prepared under solvo-thermal conditions. In 1 infinite 1D {Ba-X-Cd} (X=O, Cl) inorganic chains are linked via these full de-pronated tp^2- ligands forming a unique 3D I¹O² type micro-porous coordination framework. PXRD patterns of 1 have been determined confirming pure phases of 1. Luminescence investigations suggested that 1 exhibits highly selective and sensitive sensing for trace amounts of benzaldehyde in ethanol, which provides a facile method for real-time detection of benzaldehyde. Meanwhile 1 also exhibits highly selective and sensitive sensing for Cu²⁺ over other cations with high quenching efficiency K_sv value 1.15×10⁴L·mol^-1. As far as we know, 1 represents the first example of alkaline earth-transition hetero-metallic Ba-Cd micro-porous coordination framework as bi-functional luminescent probes for Cu²⁺ and benzaldehyde.

Sonochemical synthesis of a multi-responsive regenerable water-stable zinc(II) fluorescent probe for highly selective, sensitive and real-time sensing of benzaldehyde, ferric ion and PH

In this work, a novel water-stable coordination polymer with {4⁴} network topology {[Zn(L)₂(NO₃)₂]}_n (1) (L = 4,4'-Bis(triazol-1-ylmethyl)biphenyl) has been synthesized through the hydrothermal and sonochemical approaches. 1 has been characterized by single crystal X-ray diffraction, powder X-ray diffraction (PXRD), Fourier Transform Infrared Spectroscopy, UV-vis absorption spectrum and scanning electron microscopy (SEM). PXRD patterns of the as-synthesized samples 1 have confirmed the purity of the bulky samples. In the sonochemical preparation approaches, different ultrasound irradiation power and ultrasound time were also used in order to investigate the impact factor for morphology and size of nano-structured 1. Photo-luminescence studies have revealed that 1 can efficiently distinguish Fe³⁺ from Fe²⁺ and other metal ions. On the other hand, 1 also can exhibit a highly sensitive, excellently selective and real-time detection of benzaldehyde and pH through photo-luminescence quenching process. As for 1, density functional theory (DFT) and time-dependent DFT (TDDFT) theory has been applied to calculate these spectroscopic data, the result agree with the experimental results for detection of benzaldehyde. Photo-luminescent recyclability results indicated 1 can be reused at least five times in the detection process. To the best of our knowledge, this is the first example of a multi-responsive regenerable luminescent sensor for highly selective, sensitive and real-time sensing of Fe³⁺ over Fe²⁺, benzaldehyde and pH values.

A DFT study of the catalytic pyrolysis of benzaldehyde on ZnO, γ-Al2O3, and CaO models

The catalytic pyrolysis pathways of carbonyl compounds in coal were systematically studied using density functional theory (DFT), with benzaldehyde (C₆H₅CHO) employed as a coal-based model compound and ZnO, γ-Al₂O₃, and CaO as catalysts. The results show that the products of both pyrolysis and catalytic pyrolysis are C₆H₆ and CO. However, the presence of any of the catalysts changes the reaction pathway and reduces the energy barrier, indicating that these catalysts promote C₆H₅CHO decomposition. Graphical abstract The presence of catalysts changes the reaction pathway and the energy barrier decreases in the order Ea (no catalyst)> Ea (CaO)> Ea (γ-Al₂O₃)> Ea (ZnO), indicating that these catalysts promote C₆H₅CHO decomposition.

Highly selective oxidation of styrene to benzaldehyde over a tailor-made cobalt oxide encapsulated zeolite catalyst

A tailor-made catalyst with cobalt oxide particles encapsulated into ZSM-5 zeolites (Co₃O₄@HZSM-5) was prepared via a hydrothermal method with the conventional impregnated Co₃O₄/SiO₂ catalyst as the precursor and Si source. Various characterization results show that the Co₃O₄@HZSM-5 catalyst has well-organized structure with Co₃O₄ particles compatibly encapsulated in the zeolite crystals. The Co₃O₄@HZSM-5 catalyst was employed as an efficient catalyst for the selective oxidation of styrene to benzaldehyde with hydrogen peroxide as a green and economic oxidant. The effect of various reaction conditions including reaction time, reaction temperature, different kinds of solvents, styrene/H₂O₂ molar ratio and catalyst dosage on the catalytic performance were systematically investigated. Under the optimized reaction condition, the yield of benzaldehyde can achieve 78.9% with 96.8% styrene conversion and 81.5% benzaldehyde selectivity. Such an excellent catalytic performance can be attributed to the synergistic effect between the confined reaction environment and the proper acidic property. In addition, the reaction mechanism with Co₃O₄@HZSM-5 as the catalyst for the selective oxidation of styrene to benzaldehyde was reasonably proposed.

Design and synthesis of an indol derivative as antibacterial agent against Staphylococcus aureus

Several indole derivatives with antibacterial activity have been prepared using different protocols; however, some require special reagents and conditions. The aim of this study involved the synthesis of some indole derivatives using estrone and OTBS-estrone as chemical tools. The synthesis of the indole derivatives involves reactions such as follows: (1) synthesis of two indol derivatives (4 or 5) by reaction of estrone or OTBS-estrone with phenylhydrazine in medium acid; (2) reaction of 4 or 5 with 6-cloro-1-hexyne in medium basic to form two hexynyl-indol (7 or 8); (3) preparation of indol-propargylic alcohol derivatives (10 or 11) by reaction of benzaldehyde with 7 or 8 in medium basic; (4) synthesis of indol-aldehydes (12 or 13) via oxidation of 10 or 11 with DMSO; (5) synthesis of indeno-indol-carbaldehyde (15 or 16) via alkynylation/cyclization of 12 or 13 with hexyne in presence of copper(II); (6) preparation indeno-indol-carbaldehyde complex (19 or 20) via alkynylation/cyclization of 12 or 13 with 1-(hex-5-yn-1-yl)-2-phenyl-1H-imidazole. The antibacterial effect exerted by the indol-steroid derivatives against Streptococcus pneumoniae and Staphylococcus aureus bacteria was evaluated using dilution method and the minimum inhibitory concentration (MIC). The results showed that only the compound 19 inhibit the growth bacterial of S. aureus. In conclusion, these data indicate that antibacterial activity of 19 can be due mainly to functional groups involved in the chemical structure in comparison with the compounds studied.

Synthesis and biological evaluation of novel hydroxybenzaldehyde-based kojic acid analogues as inhibitors of mushroom tyrosinase

Two series of novel kojic acid analogues (4a-j) and (5a-d) were designed and synthesized, and their mushroom tyrosinase inhibitory activities was evaluated. The result indicated that all the synthesized derivatives exhibited excellent tyrosinase inhibitory properties having IC₅₀ values in the range of 1.35±2.15-17.50±2.75μM, whereas standard inhibitor kojic acid have IC₅₀ values 20.00±1.08μM. Specifically, 5-phenyl-3-[5-hydroxy-4-pyrone-2-yl-methylmercap-to]-4-(2,4-dihydroxyl-benzylamino)-1,2,4-triazole (4f) exhibited the most potent tyrosinase inhibitory activity with IC₅₀ value of 1.35±2.15μM. The kinetic studies of the compound (4f) demonstrated that the inhibitory effects of the compound on the tyrosinase were belonging to competitive inhibitors. Meanwhile, the structure-activity relationship was discussed.

Benzaldehyde in cherry flavour as a precursor of benzene formation in beverages

During sampling and analysis of alcohol-free beverages for food control purposes, a comparably high contamination of benzene (up to 4.6μg/L) has been detected in cherry-flavoured products, even when they were not preserved using benzoic acid (which is a known precursor of benzene formation). There has been some speculation in the literature that formation may occur from benzaldehyde, which is contained in natural and artificial cherry flavours. In this study, model experiments were able to confirm that benzaldehyde does indeed degrade to benzene under heating conditions, and especially in the presence of ascorbic acid. Analysis of a large collective of authentic beverages from the market (n=170) further confirmed that benzene content is significantly correlated to the presence of benzaldehyde (r=0.61, p<0.0001). In the case of cherry flavoured beverages, industrial best practices should include monitoring for benzene. Formulations containing either benzoic acid or benzaldehyde in combination with ascorbic acid should be avoided.

Engineering Escherichia coli for renewable benzyl alcohol production

Benzyl alcohol is an aromatic hydrocarbon used as a solvent and an intermediate chemical in the pharmaceutical, cosmetics, and flavor/fragrance industries. The de novo biosynthesis of benzyl alcohol directly from renewable glucose was herein explored using a non-natural pathway engineered in Escherichia coli. Benzaldehyde was first produced from endogenous phenylpyruvate via three heterologous steps, including hydroxymandelate synthase (encoded by hmaS) from Amycolatopsis orientalis, followed by (S)-mandelate dehydrogenase (encoded by mdlB) and phenylglyoxylate decarboxylase (encoded by mdlC) from Pseudomonas putida ATCC 12633. The subsequent rapid and efficient reduction of benzaldehyde to benzyl alcohol occurred by the combined activity and native regulation of multiple endogenous alcohol dehydrogenases and/or aldo-keto reductases. Through systematic deletion of competing aromatic amino acid biosynthesis pathways to promote endogenous phenylpyruvate availability, final benzyl alcohol titers as high as 114±1 mg/L were realized, representing a yield of 7.6±0.1 mg/g on glucose and a ~5-fold improvement over initial strains.

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A novel pathway to benzyl alcohol has been systematically engineered.

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Maximum titers reached 114±1 mg/L at a yield of 7.6±0.1 mg/g on glucose.

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Pathway flux limited by hydroxymandelate synthase, the first committed step.

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Product toxicity poorly represented by membrane accumulation/disruption model.

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The pathway can further serve as a platform for producing benzaldehyde.

Proteins involved in wine aroma compounds metabolism by a Saccharomyces cerevisiae flor-velum yeast strain grown in two conditions

A proteomic and exometabolomic study was conducted on Saccharomyces cerevisiae flor yeast strain growing under biofilm formation condition (BFC) with ethanol and glycerol as carbon sources and results were compared with those obtained under no biofilm formation condition (NBFC) containing glucose as carbon source. By using modern techniques, OFFGEL fractionator and LTQ-Orbitrap for proteome and SBSE-TD-GC-MS for metabolite analysis, we quantified 84 proteins including 33 directly involved in the metabolism of glycerol, ethanol and 17 aroma compounds. Contents in acetaldehyde, acetic acid, decanoic acid, 1,1-diethoxyethane, benzaldehyde and 2-phenethyl acetate, changed above their odor thresholds under BFC, and those of decanoic acid, ethyl octanoate, ethyl decanoate and isoamyl acetate under NBFC. Of the twenty proteins involved in the metabolism of ethanol, acetaldehyde, acetoin, 2,3-butanediol, 1,1-diethoxyethane, benzaldehyde, organic acids and ethyl esters, only Adh2p, Ald4p, Cys4p, Fas3p, Met2p and Plb1p were detected under BFC and as many Acs2p, Ald3p, Cem1p, Ilv2p, Ilv6p and Pox1p, only under NBFC. Of the eight proteins involved in glycerol metabolism, Gut2p was detected only under BFC while Pgs1p and Rhr2p were under NBFC. Finally, of the five proteins involved in the metabolism of higher alcohols, Thi3p was present under BFC, and Aro8p and Bat2p were under NBFC.

Benzaldehyde suppresses murine allergic asthma and rhinitis

To evaluate the antiallergic effects of oral benzaldehyde in a murine model of allergic asthma and rhinitis, we divided 20 female BALB/c mice aged 8-10 weeks into nonallergic (intraperitoneally sensitized and intranasally challenged to normal saline), allergic (intraperitoneally sensitized and intranasally challenged to ovalbumin), and 200- and 400-mg/kg benzaldehyde (allergic but treated) groups. The number of nose-scratching events in 10 min, levels of total and ovalbumin-specific IgE in serum, differential counts of inflammatory cells in bronchoalveolar lavage (BAL) fluid, titers of Th2 cytokines (IL-4, IL-5, IL-13) in BAL fluid, histopathologic findings of lung and nasal tissues, and expressions of proteins involved in apoptosis (Bcl-2, Bax, caspase-3), inflammation (COX-2), antioxidation (extracellular SOD, HO-1), and hypoxia (HIF-1α, VEGF) in lung tissue were evaluated. The treated mice had significantly fewer nose-scratching events, less inflammatory cell infiltration in lung and nasal tissues, and lower HIF-1α and VEGF expressions in lung tissue than the allergic group. The number of eosinophils and neutrophils and Th2 cytokine titers in BAL fluid significantly decreased after the treatment (P<0.05). These results imply that oral benzaldehyde exerts antiallergic effects in murine allergic asthma and rhinitis, possibly through inhibition of HIF-1α and VEGF.

Synthesis, characterization and antibacterial activity of biodegradable films prepared from Schiff bases of zein

Pure zein is known to be very hydrophobic, but is still inappropriate for coating and film applications because of their brittle nature. In an attempt to improve the flexibility and the antimicrobial activity of these coatings and films, Chemical modification of zein through forming Schiff bases with different phenolic aldhydes was tried. Influence of this modifications on mechanical, topographical, wetting properties and antimicrobial activity of zein films were evaluated. The chemical structure of the Schiff bases films were characterized by ATR-FTIR spectroscopy. The results indicate an improvement in mechanical properties with chemically modification of zein to form Schiff bases leading to a reduction in the elastic modulus. An increase in the elongation at break has been observed, but with slight influence on tensile strength. Plasticized zein films have similar initial contact angle (∼40°). An increase in reaction temperature and time increases film's affinity towards water. As shown by contact angle measurements, a noticeable relation was found between film composition and the hydrophilicity. Surface topography also varied by forming Schiff bases, becoming rougher than zein-based films. The antibacterial activities of zein and Schiff bases of zein-based films were investigated against gram-positive bacteria (Listeria innocua, Listeria monocytogenes, Bacillus cereus and Clostridium sporogenes) and gram-negative bacteria (Escherichia coli, Yersinia enterocolitica and Salmonella enterica). It was found that the antibacterial activity of the Schiff bases-based films was more effective than that of zein-based films.