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• Diastase activity decreases faster in mānuka honey compared to other floral types. • Methylglyoxal and 3-phenyllactic acid accelerate loss of diastase. • Diastase is not a good indicator of heat treatment or storage in mānuka honey. Diastase is used internationally as a quality monitor for excessive heat treatment and prolonged storage of honey; honey must contain an activity of at least 8 diastase numbers (DN) for it to be considered export quality. Freshly harvested mānuka honey can have diastase activity close to the export threshold of 8 DN without excess heating, increasing susceptibility for export failure. This research investigated the effect of compounds unique to or high in concentration in mānuka honey on diastase activity. Investigation of the effect of methylglyoxal, dihydroxyacetone, 2-methoxybenzoic acid, 3-phenyllatic acid, 4-hydroxyphenyllactic acid and 2′–methoxyacetophenone on diastase activity was carried out. Mānuka honey was stored at 20 and 27 °C and clover honey spiked with compounds of interest were stored at 20, 27 and 34 °C and monitored overtime. Methylglyoxal and 3-phenyllactic acid were found to accelerate the loss of diastase above the loss normally observed with time and elevated temperature. [ABSTRACT FROM AUTHOR]

Some of the most commonly occurring but difficult to isolate halophilic prokaryotes, Archaea as well as Bacteria, require or prefer pyruvate as carbon and energy source. The most efficient media for the enumeration and isolation of heterotrophic prokaryotes from natural environments, from freshwater to hypersaline, including the widely used R2A agar medium, contain pyruvate as a key ingredient. Examples of pyruvate-loving halophiles are the square, extremely halophilic archaeon Haloquadratum walsbyi and the halophilic gammaproteobacterium Spiribacter salinus. However, surprisingly little is known about the availability of pyruvate in natural environments and about the way it enters the cell. Some halophilic Archaea (Halorubrum saccharovorum, Haloarcula spp.) partially convert sugars and glycerol to pyruvate and other acids (acetate, lactate) which are excreted to the medium. Pyruvate formation from glycerol was also shown during a bloom of halophilic Archaea in the Dead Sea. However, no pyruvate transporters were yet identified in the genomes of halophilic Archaea, and altogether, our understanding of pyruvate transport in the prokaryote world is very limited. Therefore, the preference for pyruvate by fastidious and often elusive halophiles and the empirically proven enhanced colony recovery on agar media containing pyruvate are still poorly understood.

Dihydroxyacetone (DHA) occurs in wide-ranging organisms, including plants, and can undergo spontaneous conversion to methylglyoxal (MG). While the toxicity of MG to plants is well-known, the toxicity of DHA to plants remains to be elucidated. We investigated the effects of DHA and MG on Arabidopsis. Exogenous DHA at up to 10 mm did not affect the radicle emergence, the expansion of green cotyledons, the seedling growth, or the activity of glyoxalase II, while DHA at 10 mm inhibited the root elongation and increased the activity of glyoxalase I. Exogenous MG at 1.0 mm inhibited these physiological responses and increased both activities. Dihydroxyacetone at 10 mm increased the MG content in the roots. These results indicate that DHA is not so toxic as MG in Arabidopsis seeds and seedlings and suggest that the toxic effect of DHA at high concentrations is attributed to MG accumulation by the conversion to MG., (© The Author(s) 2023. Published by Oxford University Press on behalf of Japan Society for Bioscience, Biotechnology, and Agrochemistry.)

We report a new and efficient one‐pot oxidation of glycerol to dihydroxyacetone by using cheap and safe positive chlorine sources in presence of a Lewis acid catalyst. High selectivity and yields were obtained under mild conditions. The best results were obtained with aluminium chloride hexahydrate, but also zeolites or alumina can catalyse the reaction. This methodology provides a direct and convenient chemical route for the production of dihydroxyacetone. Due to the limitations of the biotechnological process for the conversion of glycerol into dihydroxyacetone, a chemical alternative procedure has attracted much research attention. By using positive chlorine sources in presence of Lewis acids, selective and quantitative oxidation of glycerol to dihydroxyacetone is carried out. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Isobornyl groups can be successfully incorporated into PU by thiol-ene reaction and poly-addition. • Introduction of isobornyl groups into PU markedly increases anti-bacterial adhesion performance. • The hydrophobicity of the coating films are significantly improved as a result. Abstract We report a novel environmental friendly waterborne polyurethane (WPU) coating with good anti-bacterial adhesion property and hydrophobicity. A key point of our approach is to functionize the polyurethane with isobornyl acrylate (IBA), a widely used natural material with unique chiral feature and good biocompatibility. The polyurethanes containing IBA have been synthesized by thiol-ene Michael addition reaction and poly-addition polymerization. The thiol monomer 3-mercapto-1,2-propanediol (TPG) and vinyl monomer isobornyl acrylate (IBA) have been used to obtain dihydroxy-terminated IBA (IBA(OH) 2) with triethylamine as catalyst. The structure of IBA(OH) 2 have been identified by Fourier transform infrared spectrum (FTIR), proton nuclear magnetic resonance (1H NMR), and mass spectrometry (MS). IBA(OH) 2 is then incorporated into polyurethane as a chain extender to yield a WPU with IBA side group (IWPU). The synthesized IWPU has been confirmed by FTIR, 1H NMR, X-ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC). Thermogravimetric Analysis (TGA) measurements indicate that the thermal stability of IWPU is decreased slightly with the increasing content of IBA(OH) 2. Differential scanning calorimetry further (DSC) indicate that the T g of the IWPU coatings decreases, and the resistance to low temperature increases at a higher content of IBA(OH) 2.The introduction of IBA side groups can improve the hydrophobicity of the polyurethane, which is favorable for wide application of the coatings. Additionally, the antibacterial adhesion performance of the polyurethanes has been evaluated by plate count method and optical density (OD) test. The results demonstrate that the polyurethane coatings with 25 wt% content of IBA side groups can exhibit effective resistance to bacterial adhesion, with the inhibition ratios of 89.3% and 80.4% for E. coli and S. aureus , respectively. [ABSTRACT FROM AUTHOR]

Sn-containing MFI zeolites with controllable Al contents were successfully synthesized with the utilization of the EDTA-Sn complex as tin source and citrate as buffer solution for the first time. The elaborately strategy achieves a right release of Sn 4+ ions rate to combine with the silicon tetrahedron species in the synthesis process which could make the heteroatom tin warmly incorporate into the zeolite frameworks. The structural information about the Sn-containing MFI zeolites was confirmed by XRD, FTIR, and solid-state NMR spectroscopy. Characterization results of HRTEM, FTIR, XPS, and UV-vis spectroscopy illustrated that most Sn species exist as isolated tetrahedral Sn(IV) in the as-prepared zeolites. The creation of Lewis acid sites in Sn-MFI and Sn-Al-MFI zeolites, and Brønsted acid sites in Sn-Al-MFI zeolites were determined by FTIR spectroscopy of pyridine adsorption and 1 H and 31 P MAS NMR spectroscopy after ammonia and trimethylphosphine oxide (TMPO) adsorption. Both the Sn-MFI and Sn-Al-MFI zeolite catalysts exhibit a remarkable catalytic performance in the conversion of dihydroxyacetone (DHA) to methyl lactate (ML), while the bifunctional Sn-Al-MFI catalyst exhibits a significant combination effect, and a remarkable active site-based turnover frequency with a high methyl lactate productivity can be achieved. [ABSTRACT FROM AUTHOR]

Copyright of Research Papers of the Wroclaw University of Economics / Prace Naukowe Uniwersytetu Ekonomicznego we Wroclawiu is the property of Uniwersytet Ekonomiczny we Wroclawiu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding of selective base‐free oxidation of glycerol to dihydroxyacetone (DHA) over Pt‐based catalysts is of paramount scientific and industrial importance. In this work, a comparative study between differently sized SbOx‐promoted and unpromoted Pt/CNTs catalysts is carried out to decouple the promoter effects from the metal size effects. The introduction of SbOx appears to enhance both the glycerol oxidation activity and the DHA selectivity, and the largely sized promoted Pt/CNTs catalysts afford a relatively high DHA yield and less C–C bond cleavage. X‐ray photoelectron spectroscopy measurements reveal that the Sb species are mainly in the form of SbOx, and the differently sized promoted catalysts show similar metal binding energies. Furthermore, theoretical studies on the promotional effects of SbOx are carried out by DFT calculations. It is found that the presence of the promoter on the catalyst surface favors the preferential activation of the secondary hydroxyl group. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3979–3987, 2018 [ABSTRACT FROM AUTHOR]

[Display omitted] • Brønsted and Lewis acid solids efficiently promote triose conversion into valuable oxygenates. • Selectivity toward final products depends on catalyst Brønsted or Lewis acid sites. • A pseudohomogeneous kinetic model fits well the catalytic results. • Kinetic constant (k 6) of ethyl lactate formation step is higher on Lewis acid catalysts. • Kinetic constant (k 5) of pyruvic aldehyde diethyl acetal is higher on Brønsted acid catalysts. The effect of catalyst acid site nature on the reaction kinetics of the liquid-phase conversion of dihydroxyacetone with ethanol was investigated using Brønsted and Lewis acid solids. The reaction proceeds through a complex reaction network involving a sequence of consecutive and parallel reaction steps. Main final products were ethyl lactate and pyruvic aldehyde diethyl acetal. Different catalysts such as the cesium salt of tungstophosphoric acid (Cs-HPA), Amberlyst resin and alumina-supported tin and zinc oxides were used. Catalysts were characterized by ICP, X-ray diffraction, N 2 physisorption, TPD of NH 3 and FTIR of adsorbed pyridine. Cs-HPA contains only Brønsted acid sites and alumina-supported tin and zinc samples show exclusively Lewis acidity. During dihydroxyacetone conversion, the selectivities to the final products strongly depend on the nature of the surface acid sites present on the solids. Brønsted acid solids favor the synthesis of pyruvic aldehyde diethyl acetal with final yields of up to 93%, whereas the ethyl lactate is the main product on Lewis acid solids, reaching final yields of about 51%. A kinetic model based on a pseudohomogeneous mechanism was proposed to interpret the experimental catalytic data. The comparison of the kinetic rate constants obtained on both kinds of acid solids confirms that on Brønsted catalysts the route toward pyruvic aldehyde diethyl acetal is clearly favored. On Lewis solids, the synthesis of ethyl lactate occurs selectively via isomerization of the pyruvic aldehyde hemiacetal intermediate. [ABSTRACT FROM AUTHOR]

The reaction of perfluorobiacetyl with thiourea produced 4,5-dihydroxy-4,5-bis(trifluoromethyl)imidazolidine-2-thione, mainly in trans -form, in a yield of ∼60%. 4,5-Dihydroxy-4,5-bis(trifluoromethyl)imidazolidine-2-thione(one) were introduced for the first time in the condensation with thiourea in dimethylacetamide at elevated temperature and trifluoromethylated thioxo(oxo)imidazothiazolones were unexpectedly obtained (yield ∼41 − 30%). A similar reaction of 4,5-dihydroxy-4,5-bis(trifluoromethyl)imidazolidine-2-thione(one) with NH 4 SCN and 4,5-dihydroxy-4,5-bis(trifluoromethyl)imidazolidine-2-thione with N -alkyl(aryl)ureas and N,N' -dialkyl(diaryl)ureas afforded the same thioxo(oxo)imidazothiazolones (yield ∼50 − 16%). In contrast to it, the condensation of 4,5-dihydroxy-4,5-bis(trifluoromethyl)imidazolidine-2-thione with urea under similar conditions gave mainly trifluoromethylated thioglycoluril in ∼31% yield. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Nicotinamide cofactor‐dependent oxidoreductases have been widely applied to the bioproduction of varieties of useful compounds. Efficient cofactor regeneration is often required for these oxidoreductase‐catalyzed reactions. Herein, enzymatic production of 1, 3‐dihydroxyacetone (DHA) via immobilized enzymes with in situ cofactor regeneration was reported. RESULTS: Glycerol dehydrogenase (GDH) and NADH oxidase (Nox) were immobilized on two carriers: macroporous resin and epoxy functionalized magnetic nanoparticles (EFMN). Higher enzyme loading capacity and activity recovery were achieved on EFMN. A high immobilization yield of 90% and >70% recovery activity were obtained for both enzymes using EFMN as carriers. Besides, both immobilized enzymes showed enhanced pH stability and temperature tolerance. Co‐immobilized and mixed immobilized enzymes were evaluated for synthesis of DHA, and mixed immobilized enzymes showed higher catalytic rate. The mixed reaction system also was investigated in view of various operational factors. Under the optimal conditions, a high DHA concentration with mixed immobilized enzymes system can reach up to 3.5 mmol L–1, which was about four times higher than that without cofactor regeneration system. CONCLUSION: The immobilized GDH and Nox on magnetic nanoparticles showed enhanced stabilities. A cofactor regeneration system with immobilized enzymes could be utilized for efficient production of DHA from inexpensive substrates. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Copyright of Technical Transactions / Czasopismo Techniczne is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: In a search for novel vitamin D derivatives of potential therapeutic value, structurally simple but synthetically challenging A‐ring epimers of the 19‐nor‐Calcitriol [19‐nor‐1α,25‐(OH)2‐D3] at C1 and C3 were efficiently synthesized. Both analogues (1‐epi‐ and 3‐epi‐19‐nor‐Calcitriol) were obtained through a convergent synthesis starting from cis,cis‐1,3,5‐cyclohexanetriol and the protected 25‐hydroxy Grundmann′s ketone. After Julia‐Kocienski coupling of the corresponding C,D‐ring/side chain sulfone fragment with the A‐ring ketone moiety, both vitamin D analogues were isolated. The critical point was how to determine the structural configuration of both diastereoisomers since similar 1H NMR spectra were observed. For that, a biocatalytic approach was crucial in the synthesis of orthogonally protected derivatives. NMR spectroscopy allows the unambiguous identification of these compounds and as a result the structural elucidation of the desired vitamin D diastereomeric analogues. Affinity studies demonstrated that these 1,25‐19‐nor analogues have a very low affinity for the vitamin D receptor compared with 1α,25‐dihydroxyvitamin D3 or 1α,25‐dihydroxy‐19‐nor‐vitamin D3. In addition, these analogues have a lower binding affinity for the human vitamin D binding protein than the natural hormone. In vitro cell culture studies revealed that synthesized analogues were less active than 1α,25‐dihydroxyvitamin D3 in inhibiting cell proliferation. [ABSTRACT FROM AUTHOR]

Abstract: Existing dihydroxyacetone (DHA) production practices require the use of yeast extracts, leading to relatively high production costs. This study explores the use of low‐cost media comprising glycerol, inorganic salts and Gluconobacter frateurii BCC 36199 in the production of DHA. The medium components are also quantitatively optimized. Regression models describing the linear correlations between the nutrient concentrations and the generated DHA concentration (p), and between the nutrient concentrations and the yield (ysp) are developed. Under the optimal conditions according to our regression models, the highest values for p and ysp are 29·36 g l−1 and 97·86% g g−1 respectively. Quantitatively, this study shows positive effects of inorganic salts and adverse effects of excessive amounts of glycerol on DHA production. In particular, the results suggest that low levels of biomass production lead to high levels of DHA production. Consequently, the media containing inorganic nitrogen source from (NH4)2SO4 lead to higher yields than organic media containing yeast extract. This study has identified an optimal, low‐cost, minimal medium that can effectively enhance DHA production. Significance and Impact of the Study: This study illustrates the advantages of inorganic nutrients supplementation over organic nutrient supplementation for a lower media cost and a higher dihydroxyacetone (DHA) production yield through Gluconobacter frateurii BCC 36199 cultivation. The study found that the use of media that contain only glycerol and inorganic salts enhanced DHA production (DHA‐Prod) while keeping the production of bacterial biomass at a sufficient level. Most of the starting material, that is, glycerol, is converted into DHA, which is the target of the production process. The cost of the nitrogen supplement in the DHA‐Prod process may be reduced by up to 80% through the use of the inorganic culture medium that has been developed in this study. [ABSTRACT FROM AUTHOR]

Purpose: Although 1H spin coupling is generally avoided in probes for hyperpolarized (HP) 13C MRI, enzymatic transformations of biological interest can introduce large 13C‐1H couplings in vivo. The purpose of this study was to develop and investigate the application of 1H decoupling for enhancing the sensitivity for detection of affected HP 13C metabolic products. Methods: A standalone 1H decoupler system and custom concentric 13C/1H paddle coil setup were integrated with a clinical 3T MRI scanner for in vivo 13C MR studies using HP [2‐13C]dihydroxyacetone, a novel sensor of hepatic energy status. Major 13C‐1H coupling JCH = ∼150 Hz) is introduced after adenosine triphosphate–dependent enzymatic transformation of HP [2‐13C]dihydroxyacetone to [2‐13C]glycerol‐3‐phosphate in vivo. Application of WALTZ‐16 1H decoupling for elimination of large 13C‐1H couplings was first tested in thermally polarized glycerol phantoms and then for in vivo HP MR studies in three rats, scanned both with and without decoupling. Results: As configured, 1H‐decoupled 13C MR of thermally polarized glycerol and the HP metabolic product [2‐13C]glycerol‐3‐phosphate was achieved at forward power of approximately 15 W. High‐quality 3‐s dynamic in vivo HP 13C MR scans were acquired with decoupling duty cycle of 5%. Application of 1H decoupling resulted in sensitivity enhancement of 1.7‐fold for detection of metabolic conversion of [2‐13C]dihydroxyacetone to HP [2‐13C]glycerol‐3‐phosphate in vivo. Conclusions: Application of 1H decoupling provides significant sensitivity enhancement for detection of HP 13C metabolic products with large 1H spin couplings, and is therefore expected to be useful for preclinical and potentially clinical HP 13C MR studies. Magn Reson Med 80:36–41, 2018. © 2017 International Society for Magnetic Resonance in Medicine. [ABSTRACT FROM AUTHOR]

The first total synthesis of the originally proposed and correct structures of hetiamacin A has been accomplished via Wittig olefination and Sharpless asymmetric dihydroxylation reaction. These total syntheses culminated in the stereostructural confirmation of the reassignment of hetiamacin A. [ABSTRACT FROM AUTHOR]

Aluminium phosphide (AlP), a very toxic pesticide also known as the rice tablet, releases phosphine gas upon contact with water, moisture, or gastric acid. Its mortality rate in humans is 70-100 % due to cardiogenic shock and refractory hypotension. Dihydroxyacetone (DHA) is a simple ketonic carbohydrate, mainly used for sunless skin tanning. It also plays a beneficial role in the treatment of hypotension and cardiogenic shock by restoring blood volume and cellular respiration. The aim of this study was to investigate the its effect on the haemodynamics and electrocardiogram (ECG) in male rats poisoned with AlP. The animals were divided into the following groups: control (received 1 mL corn oil, orally), AlP (received 15 mg kg-1 AlP solved in corn oil, orally), AlP plus DHA (treated with 50 mg kg-1 of DHA 30 min after receiving AlP), and AlP plus N-acetyl cysteine (NAC) (treated with 200 mg kg-1 of NAC 30 min after receiving AlP). The animals were then anaesthetised and ECG, blood pressure, and heart rate were recorded for 120 min. Treatment with AlP alone and in combination with NAC was associated with progressive hypotension, tachycardia, and ECG disturbances in rats, resulting in 100 % mortality 3 h after poisoning. However, DHA achieved 100 % survival in the poisoned rats and prevented AlP-induced ECG and haemodynamic abnormalities. The main mechanism of DHA in the treatment of AlP poisoning is unclear, but the findings suggest the promising therapeutic potential of DHA against AlP poisoning. [ABSTRACT FROM AUTHOR]

This study reports crude glycerol fermentation by G. oxydans for dihydroxyacetone (DHA) production, and intensification of fermentation with sonication. Fermentation was carried out using both free and immobilized cells (on polyurethane foam support) for initial glycerol concentrations of 20, 30 and 50 g/L. Sonication at 20% duty cycle enhanced glycerol consumption by 60–84% with no significant change in cell morphology. Lesser DHA yield in crude glycerol fermentation was attributed to possible formation of inhibitory products. Slight reduction in DHA yield for initial glycerol concentration of 50 g/L was attributed to substrate inhibition. Higher DHA productivity was obtained for immobilized cells. Circular dichroism analysis of intracellular proteins obtained from ultrasound-treated G. oxydans revealed significant reduction in α -helix and β -sheet content. These conformational changes in protein structure could augment activity of intracellular glycerol dehydrogenase, which is manifested in terms of enhanced metabolism of glycerol by G. oxydans . [ABSTRACT FROM AUTHOR]

Recently, we reported the presence of dihydroxyacetone (DHA), the active ingredient in sunless tanners, in the aerosol of an electronic cigarette. DHA has been shown to react with DNA in vitro. The FDA restricts the use of DHA to external application only. It states that it should not be inhaled, ingested, or come into contact with any areas containing mucous membranes, due to unknown risk. Herein, the quantification of DHA in the aerosols of three brands of e-cigarettes has been carried out. These included two devices with horizontal heating coil configurations as well as one with a sub-ohm resistance vertical heating coil. In order to understand and begin to address the origin of DHA and related aerosol products, the wicking properties of the three e-cigarettes were compared. DHA levels were analyzed by a combination of GS/MS and 1H NMR. DHA was found in all three ecigarettes, with substantially less in the sub-ohm, vertical coil device as compared to the horizontal coil devices (e.g., 0.088 μg/puff vs. 2.29 μg/puff, respectively). Correspondingly, the temperature of the wet layer of the wick for the vertical coil was relatively stable, compared to the wicks for the horizontal coils, upon increasing battery power output. This result is in agreement with prior studies of e-cigarette wicking efficiency and aerosol toxin formation. The temperature measurements reported are a simple means for comparing devices with different design properties during operation. [ABSTRACT FROM AUTHOR]

1,3-Dihydroxyacetone, a common cosmetic material and food additive, has been successfully explored as an efficient electrochemiluminescence coreactant of Ru(bpy)32+ for the first time. It is about 25 times more effective than the well-known coreactant sodium oxalate. The high electrochemiluminescence efficiency allows sensitive detection of 1,3-dihydroxyacetone without any derivatization. The electrochemiluminescence method shows two linear electrochemiluminescence responses over the range of 5.0-500 μM and 500 μM-6.0 mM with a detection limit of 1.79 μM. The proposed method is at least two orders of magnitude more sensitive than other reported methods.ECL intensity-potential profile of 1,3-dihydroxyacetone (DHA) and oxalate [ABSTRACT FROM AUTHOR]

Abstract: Currently obtained from glycerol through microbial fermentation, the demand of 1,3‐dihydroxyacetone (DHA) has significantly grown during the course of the last decade, driven by the consumer passion for a tan and increasing awareness of UV photodamage to the skin caused by prolonged exposure to the sun. We provide an updated bioeconomy perspective into a valued bioproduct (DHA), whose supply and production from glycerol, we argue in this study, will rapidly expand and diversify, with important global health benefits. [ABSTRACT FROM AUTHOR]

Abstract: The active ingredient in sunless tanning products (STPs) is a simple sugar, dihydroxyacetone (DHA). Several studies have demonstrated that DHA is absorbed within the viable layers of skin and not fully contained within the stratum corneum. Additionally, spray tanning and other aerosolized application methods have increased the risk of internal exposure through mucous membranes and inhalation. Beyond its presence in STPs, DHA also occurs as an endogenous by‐product of fructose metabolism, and an excess of DHA in cells can induce advanced glycation end (AGE) products and oxidative stress. Therefore, exogenous and endogenous exposures to DHA may be harmful to cells, and it has already been demonstrated that exogenous exposure to DHA is cytotoxic in immortalized keratinocytes. Still, little is known about the exogenous DHA exposure effects on other skin components. In this study, we explore the effects of exogenous DHA exposure in a human melanoma cell line, A375P. Melanoma cells were sensitive to DHA and displayed a transient burst of reactive oxygen species within an hour of exposure. Cell cycle arrest at G2/M was observed within 24 h of exposure, and apoptosis, monitored by the cleavage of PARP‐1 and Caspase‐3, was detected within 72 h of exposure to DHA. Together, these demonstrate that exogenous exposure to DHA has cytotoxic effects in our selected cell model and indicates the need to further investigate the exogenous exposure effects of DHA in other relevant exposure models. [ABSTRACT FROM AUTHOR]

• Background and Aims Floral nectar can be variable in composition, influencing pollinator behaviour and the composition of honey derived from it. The non-peroxide antibacterial activity of mānuka (Leptospermum scoparium, Myrtaceae) honey results from the chemical conversion of the triose sugar dihydroxyacetone (DHA), after DHA accumulates for an unknown reason in the nectar. This study examined variation in nectar DHA, glucose, fructose and sucrose content with floral stage of development, between mānuka genotypes with differing flower morphology, and in response to water stress. • Methods Six mānuka genotypes were grown without nectar-feeding insects. Stages of flower development were defined, nectar was harvested and its composition was compared between stages and genotypes, and with floral morphology. Water stress was imposed and its effect on nectar composition was examined. • Key Results Nectar was present from soon after flower opening until the end of petal abscission, with the quantity of accumulated nectar sugars rising, then stabilizing or falling, indicating nectar secretion followed by reabsorption in some genotypes. The quantity of DHA, the ratio of DHA to other nectar sugars and the fructose to glucose ratio also varied with stage of development, indicating differences in rates of production and reabsorption between nectar components. Nectar composition and yield per flower also differed between genotypes, although neither was positively related to nectary area or stomatal density. Drying soil had no effect on nectar composition or yield, but variation in nectar yield was correlated with temperature prior to nectar sampling. • Conclusions Mānuka nectar yield and composition are strongly influenced by plant genotype, flower age and the environment. There were clear stoichiometric relationships between glucose, fructose and sucrose per flower, but DHA per flower was only weakly correlated with the amount of other sugars, suggesting that accumulation of the triose sugar is indirectly coupled to secretion of the larger sugars by the nectary parenchyma. [ABSTRACT FROM AUTHOR]

Methods for determination of glycerol and its electrooxidation products (neutral diols and carboxylates) by capillary electrophoresis (CE) with dual capacitively coupled contactless conductivity detectors (C 4 D) are presented. Glycerol, dihydroxyacetone and glyceraldehyde were detected as anionic borate complexes in less than 3 min under counter Electroosmotic Flow (EOF) mode (resolution of the critical pair of 1.8). Limits of detection (LODs) of 15, 15 and 10 µmol L −1 were obtained for glycerol, dihydroxyacetone and glyceraldehyde, respectively. Two methods of separation were used for the separation of carboxylates. The first one used the same Back Ground Electrolyte (BGE) containing borate, and the second used a BGE (pH 6.1) composed by 2-(N-morpholino)ethanesulfonic acid (MES), L -Histidine and a flow modifier. Better separation and LODs for carboxylates were obtained using Mes/Histidine as BGE. However, along with the non-applicability of this BGE to the determination of neutral diols, observation of the C 4 D signals at two different points of the capillary (10 and 50 cm apart from the injection tip) revealed interaction of the flow modifier with some species (mesoxalate and glyoxylate). The electrooxidation of a glycerol sample in alkaline media on an 8 cm 2 gold working electrode was evaluated by the developed methods. After 16 h of electrolysis, 87% of the glycerol had been oxidized and formate, glycolate, hydroxypyruvate and glycerate were detected as the main products. [ABSTRACT FROM AUTHOR]

Hierarchical zeolites containing tin were obtained, characterized and used in a reaction of catalytic isomerization of dihydroxyacetone (DHA) to lactic acid and alkyl lactates. These catalysts are characterized by preserved crystallinity and primary microporosity with the simultaneous existence of secondary porosity regarding mesopores, which facilitates access of large molecules of reagents to active centers. Creation of additional porosity was confirmed by X-ray diffraction and low-temperature nitrogen adsorption/desorption studies. The reaction of dihydroxyacetone isomerization was conducted in different reaction media such as methanol, ethanol or water with the use of two heating methods: microwave radiation and conventional heating. The application of microwave radiation enabled to reduce the reaction time to 1 h and achieve dihydroxyacetone conversion of >90% and high yields of the desired reaction products. [ABSTRACT FROM AUTHOR]

Bismuth plays important roles in promoting the oxidation of alcohols towards high-value-added chemicals over a noble metal loading catalyst. Herein, Mg-Al hydrotalcite-supported platinum-bismuth nanoparticles (Pt-Bi/HT) were prepared by the co-impregnation method and used in the selective oxidation of glycerol towards dihydroxyacetone (DHA). The incorporation of Bi species into Pt/HT significantly enhances the conversion of glycerol and the selectivity of DHA. The high selectivity of DHA with 80.6% could be achieved at 25.1% conversion of glycerol. The Bi species of the Pt-Bi/HT catalyst mainly exist in the form of BiOCl and Bi metal, which is different from the previous Pt-Bi based catalyst, confirmed by a combination of powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HR-TEM). A plausible mechanism is proposed to elucidate the promoting role of Bi species on the Pt/HT catalyst in the selective oxidation of glycerol towards DHA. [ABSTRACT FROM AUTHOR]

The public has been warned for years about the dangers of ultraviolet exposure from natural sunlight and tanning beds due to the associated risk for skin cancer development. An alternative to obtaining the sun-kissed look without ultraviolet exposure has been self-tanning products, which are applied directly to the skin via lotions, sprays, foams, and wipes. However, recent research has indicated that the chemical dihydroxyacetone (DHA), which is the active agent in most sunless tanning lotions, may cause cell damage via free radical reactions. Changes in pigmented lesion appearance during dermoscopic examinations after use of products containing DHA have been documented, and these findings will be analyzed. This integrative research review will examine evidence-based research regarding the risks of using DHA-containing products. Nola Pender's health promotion model is recommended to identify strategies that healthcare providers can use when developing anticipatory guidance to address factors leading to barriers in health promoting behaviors. This model is focused on improvement of well-being while preventing diseases. [ABSTRACT FROM AUTHOR]

CuMgAl-hydrotalcite-supported Au catalysts were prepared and tested in the selective conversion of glycerol to dihydroxyacetone. The electron density of Au was decreased by Cu embedded in the supports, arising from the electron transfer from Au to Cu sites. The valence state (+ 1) of Cu ions was detected. Both Cu and basic sites (Mg-O) affected the catalytic activity of Au catalysts. The Cu sites promoted the selective oxidation of glycerol to dihydroxyacetone, while basic sites boosted the selectivity oxidation of glycerol to glyceric acid. The synergy of Cu sites and basic sites could effectively promote the activity and selectivity of Au catalysts in the selectively conversion of glycerol to dihydroxyacetone. A 53% conversion of glycerol and 72% of dihydroxyacetone selectivity were obtained under optimum reaction conditions. [ABSTRACT FROM AUTHOR]

A series of biochemical changes occur in the muscles of postmortem fish, resulting in an extremely easy decline in freshness. The early stage of postharvest can be regarded as the quality determination period (QDP) oficeice seafood. The QDP handlings influence the final quality of fish product. Bleeding at ice seawater was conducted to lock the freshness of farmed turbot. The pH, ATP-related compounds and K values were measured. A non-target metabolomics technique was used to elucidate the mechanism of freshness-lock. The results showed that the levels of pH and ATP-related compounds were decreased slowly in the fish of freshness-lock, while K values were lower than those in no freshness-lock fish during cold storage. The metabolomics analysis revealed that 25 metabolites were significantly changed in the muscles of turbot after 2 d of cold storage. After freshness-lock treatment, 6 metabolites reversed in the muscles of turbot, with the rises in glycerol 3-phosphate, dihydroxyacetone phosphate, and decanoyl- l -carnitine and the drops in pyruvaldehyde, D-lyxose, and d -ribose. This study indicates that locking freshness during QDP of fish has a delayed effect on the quality deterioration and can prolonging the shelf-life of fresh product. • Locking freshness during QDP of fish has a delayed effect on the quality deterioration. • After bleeding in the iced seawater, the pH and ATP-related compounds were decreased slowly, and K values were lower. • There were 25 metabolites significantly changed in the muscles of turbot after 2 d of storage. • Six biomarkers were reversed in the muscles of turbot after freshness-lock treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ball-milling process induces the phase transition from tetragonal t-ZrO 2 to monoclinic m-ZrO 2. • The m-ZrO 2 support promotes performance of PtBi-catalyzed glycerol oxidation to dihydroxyacetone than t-ZrO 2. • The m-ZrO 2 support enhances dispersion of Bi-modified Pt site and surface basicity of PiBi catalyst. • Kinetic and spectral observations reveal selective dissociation of the secondary hydroxyl of glycerol. • Facile desorption of dihydroxyacetone as target product promotes the selectivity of PtBi/ZrO 2 catalyst. Catalytic oxidation of glycerol to dihydroxyacetone (DHA) represents an essential bio-upgrading process with industrial potential, and the challenging tasks are to control the selectivity for metal catalysts. This study provides insights into multiple positive roles of ball-milling-induced phase transition from tetragonal t-ZrO 2 to monoclinic m-ZrO 2 on activation of the secondary hydroxyl of glycerol over the bimetal PtBi/ZrO 2 catalysts. The mZrO 2 -BM support affords enhanced both dispersion of the Bi-modified Pt sites and surface basicity than tZrO 2 support, and therefore promotes the activity, DHA selectivity and recycling stability of the PtBi catalyst under neutral condition. Catalytic evaluation with DHA and glyceraldehyde as reactants and in-situ FT-IR spectra of isopropanol and acetone adsorption reveal that the catalyst prefers dissociative activation of the secondary hydroxyl of glycerol rather than the primary hydroxyl. The observations also demonstrate that DHA tends to be easily desorbed as target product for preventing deep oxidation or C–C cleavage into by-products. [ABSTRACT FROM AUTHOR]

The photoelectrocatalytic (PEC) valorization of glycerol is emerging for the co-generation of hydrogen and value-added organics like glyceraldehyde (GAD) or dihydroxyacetone (DHA). In this work, we have designed, tested and optimized a pioneering photoelectrolyser with a non-noble metal-based photoanode (WO 3), operating in near-neutral conditions and using a proton-exchange membrane (PEM) which ensures the elution of a purified hydrogen stream from the cathode side while selectively oxidizing glycerol on the anode. The influence of light irradiation, external bias and cell temperature has been investigated, leading to GAD and DHA production rates of 11.1 and 5.2 mmol m−2 h−1 at 60 ºC and 1.2 V, along with 44.0 mmol H 2 m−2 h−1. The long-term stability of the photoelectrolyser has also been validated and the particularities of this system with respect to other conventional devices have been discussed. PEC stands as a promising sustainable technology for the simultaneous H 2 generation and biomass valorization. [Display omitted] • The first PEM PEC cell for glycerol valorization and H2 generation was developed. • A selective WO3 photoanode, a H+ -exchange membrane and near-neutral pH were applied. • Simultaneous anodic C3s and cathodic H2 production was optimized at 60ºC and 1.2 V. • PEC favours glycerol upgrading while electrocatalysis favours mineralization. • The synergy between photo- and electrocatalysis stands PEC as a promising technology. [ABSTRACT FROM AUTHOR]

The purpose of this paper is twofold: on the one hand, we verify effectiveness of alternatives solutes to sucrose solution as osmotic agents, while on the other hand we intend to analyze modeling transfer parameters, using different models. There has also been proposed a new mass transfer parameter—true water loss, which includes actual solid gain during the process. Additional consideration of a new ratio (Cichowska et al. Ratio) can be useful for better interpretation of osmotic dehydration (OD) in terms of practical applications. Apples v. Elise were dipped into 30% concentrated solutions of erythritol, xylitol, maltitol, and dihydroxyacetone (DHA) to remove some water from the tissue. To evaluate the efficiency of these solutes, 50% concentrated sucrose solution was used as a control. All of the tested osmotic agent, except maltitol, were effective in the process as evidenced by high values in the true water loss parameter. Solutions of erythritol and xylitol in 30% concentrate could be an alternative to sucrose in the process of osmotic dehydration. Peleg’s, Kelvin–Voigt, and Burgers models could fit well with the experimental data. modeling of mass transfer parameters, using Peleg’s model can be satisfactorily supplemented by Kelvin–Voigt and Burgers model for better prediction of OD within the particular periods of the process.

Waste glycerol is the main by-product generated during biodiesel production, in an amount reaching up to 10% of the produced biofuel. Is there any method which allows changing this waste into industrial valuable compounds? This manuscript describes a method for valorization of crude glycerol via microbial bioconversion. It has been shown that the use of free and immobilized biocatalysts obtained from Gluconobacter oxydans can enable beneficial valorization of crude glycerol to industrially valuable dihydroxyacetone. The highest concentration of this compound, reaching over 20 g·L−1, was obtained after 72 h of biotransformation with free G. oxydans cells, in a medium containing 30 or 50 g·L−1 of waste glycerol. Using a free cell extract resulted in higher concentrations of dihydroxyacetone and a higher valorization efficiency (up to 98%) compared to the reaction with an immobilized cell extract. Increasing waste glycerol concentration to 50 g·L−1 causes neither a faster nor higher increase in product yield and reaction efficiency compared to its initial concentration of 30 g·L−1. The proposed method could be an alternative for utilization of a petrochemical waste into industry applicated chemicals.