High Concentrations Of Acetaldehyde Research Articles

High expression of ethylene response factor BcERF98 delays the flowering time of non-heading Chinese cabbage.

BcERF98 is induced by ethylene signaling and inhibits the expression of BcFT by interacting with BcNF-YA2 and BcEIP9, thereby inhibiting plant flowering. Several stresses trigger the accumulation of ethylene, which then transmits the signal to ethylene response factors (ERFs) to participate in the regulation of plant development to adapt to the environment. This study clarifies the function of BcERF98, a homolog of AtERF98, in the regulation of plant flowering time mediated by high concentrations of ethylene. Results indicate that BcERF98 is a nuclear and the cell membrane-localized transcription factor and highly responsive to ethylene signaling. BcERF98 inhibits the expression of BcFT by interacting with BcEIP9 and BcNF-YA2, which are related to flowering time regulation, thereby participating in ethylene-mediated plant late flowering regulation. The results have enriched the theoretical knowledge of flowering regulation in non-heading Chinese cabbage (NHCC), providing the scientific basis and gene reserves for cultivating new varieties of NHCC with different flowering times.

The responses of ‘Hayward’ kiwifruit to ethylene during regular and controlled atmosphere storage

ABSTRACT Maintaining kiwifruit firmness is key to global supply chain. Controlled atmosphere (CA) technology can maintain kiwifruit quality. However, there is a risk of ethylene (C2H4) accumulation in CA that may accelerate kiwifruit softening. The objectives of this study were to determine the impact of ethylene on kiwifruit quality in CA. ‘Hayward’ kiwifruit were stored in air and CA (5% CO2 + 2% O2) at 0°C, 95% RH for 13 weeks. Ethylene at concentrations of 10, 100, 1000 nL·L−1 was added after 3 weeks of storage. The responses of kiwifruit to ethylene were dose-dependent in both air and CA storage. Ethylene-induced kiwifruit softening was delayed and slowed by CA. However, white-core inclusions (WCI) disorder was observed after 8 weeks of exposure to 100 and 1000 nL·L−1 ethylene in CA. The lowest concentrations of ethylene (≤ 10 nL·L−1) in CA did not influence kiwifruit quality. This work demonstrates that kiwifruit sensitivity to ethylene is lower in CA than that in air, but excessive softening and WCI may negatively impact kiwifruit quality when exposed to a high ethylene concentration in CA for extended periods. Hence, ethylene monitoring and management may be less critical in kiwifruit stored in CA but are required.

Carbon‐Efficient CO2 Electrolysis to Ethylene with Nanoporous Hydrophobic Copper

AbstractElectrochemical carbon dioxide (CO2) reduction offers a low‐carbon route to ethylene, when powered from renewable energy. Yet, the best‐performing CO2 electrolysis systems employ neutral or alkaline electrolytes, resulting in low conversion efficiencies, which increases downstream separation costs. High conversion rates can be achieved with acidic electrolytes, albeit at the cost ethylene faradaic efficiency (FE < 45%). As a result, achieving high ethylene selectivity simultaneously with high conversion efficiency is an unmet challenge. Here, a 3D‐nanoporous catalyst is designed to modulate water and CO2 concentration at the catalyst surface, reaching higher ethylene selectivity in a forward‐bias bipolar MEA that recovers unreacted CO2. An ethylene FE of 63% at 150 mA cm−2 is reported, and by optimizing for conversion efficiency, an ethylene FE of 58% along with an overall conversion efficiency of 82% is achieved. Stable performance for > 65 h at industrial current densities combined with a high ethylene concentration in the product stream showcases promising industrial viability.

The Transcription Factor MiMYB8 Suppresses Peel Coloration in Postharvest 'Guifei' Mango in Response to High Concentration of Exogenous Ethylene by Negatively Modulating MiPAL1.

Anthocyanin accumulation is regulated by specific genes during fruit ripening. Currently, peel coloration of mango fruit in response to exogenous ethylene and the underlying molecular mechanism remain largely unknown. The role of MiMYB8 on suppressing peel coloration in postharvest 'Guifei' mango was investigated by physiology detection, RNA-seq, qRT-PCR, bioinformatics analysis, yeast one-hybrid, dual-luciferase reporter assay, and transient overexpression. Results showed that compared with the control, low concentration of exogenous ethylene (ETH, 500 mg·L-1) significantly promoted peel coloration of mango fruit (cv. Guifei). However, a higher concentration of ETH (1000 mg·L-1) suppressed color transformation, which is associated with higher chlorophyll content, lower a* value, anthocyanin content, and phenylalanine ammonia-lyase (PAL) activity of mango fruit. M. indica myeloblastosis8 MiMYB8 and MiPAL1 were differentially expressed during storage. MiMYB8 was highly similar to those found in other plant species related to anthocyanin biosynthesis and was located in the nucleus. MiMYB8 suppressed the transcription of MiPAL1 by binding directly to its promoter. Transient overexpression of MiMYB8 in tobacco leaves and mango fruit inhibited anthocyanin accumulation by decreasing PAL activity and down-regulating the gene expression. Our observations suggest that MiMYB8 may act as repressor of anthocyanin synthesis by negatively modulating the MiPAL gene during ripening of mango fruit, which provides us with a theoretical basis for the scientific use of exogenous ethylene in practice.

Enhanced Expression of Alcohol Dehydrogenase I in Pichia pastoris Reduces the Content of Acetaldehyde in Wines.

Acetaldehyde is an important carbonyl compound commonly detected in wines. A high concentration of acetaldehyde can affect the flavor of wines and result in adverse effects on human health. Alcohol dehydrogenase I (ADH1) in Saccharomyces cerevisiae catalyzes the reduction reaction of acetaldehyde into ethanol in the presence of cofactors, showing the potential to reduce the content of acetaldehyde in wines. In this study, ADH1 was successfully expressed in Pichia pastoris GS115 based on codon optimization. Then, the expression level of ADH1 was enhanced by replacing its promoter with optimized promoters and increasing the copy number of the expression cassette, with ADH1 being purified using nickel column affinity chromatography. The enzymatic activity of purified ADH1 reached 605.44 ± 44.30 U/mg. The results of the effect of ADH1 on the content of acetaldehyde in wine revealed that the acetaldehyde content of wine samples was reduced from 168.05 ± 0.55 to 113.17 ± 6.08 mg/L with the addition of 5 mM NADH and the catalysis of ADH1, and from 135.53 ± 4.08 to 52.89 ± 2.20 mg/L through cofactor regeneration. Our study provides a novel approach to reducing the content of acetaldehyde in wines through enzymatic catalysis.

Transient acetaldehyde production by SO2-producing <i>Saccharomyces cerevisiae</i> promotes the survival of <i>Oenococcus oeni</i> during co-fermentation

Stuck or sluggish malolactic fermentation (MLF) can be problematic in stressful wine conditions, particularly white and sparkling base musts/wines. In these cases, knowledge of yeast-bacteria strain compatibility and the amount of sulfur dioxide (SO2) a yeast strain produces are important considerations for successful MLF. Here, laboratory- and pilot-scale co-fermentations in Chardonnay were used to investigate the effect of yeast-derived SO2 on Oenococcus oeni survival. Although yeast-derived SO2 is generally inhibitory, we show that SO2 production (to approximately 65 mg/L) can be uncoupled from O. oeni survival in the early stages of co-fermentation. Bacterial survival in the presence of specific SO2-producing yeast strains was correlated with the early, transient formation of high acetaldehyde concentrations. Oenococcus oeni survival coincided with molecular SO2 concentrations remaining below an extremely low threshold of inhibition, which exponentially increased from approximately 3–6 µg/L in the first three days of co-fermentation. Strain-dependent sensitivity of O. oeni to bound SO2 remains a possibility, although the extent and mechanism of such inhibition by the SO2 adduct during co-fermentation remain unclear. The choice of co-inoculation yeast strain also influenced wine diacetyl concentration, which was only detected in wines co-inoculated with high SO2-producing S. cerevisiae strains. The wines with high diacetyl concentrations were found to be distinct by a sensory panel, with comparatively high citation frequency for a buttery sensory attribute. Both the SO2- and acetaldehyde production capacity of yeasts are, therefore, seen as meaningful co-inoculation selection criteria. The range of yeast strains suitable for MLF induction by co-inoculation could be widened to include SO2-producing strains that transiently produce an early, high concentration of acetaldehyde. The effects of low, equilibrium concentrations of molecular SO2 should also be considered in conjunction with total SO2 as a measure of SO2 toxicity towards O. oeni following co-inoculation.

Development of Distillation Sensors for Spirit Beverages Production Monitoring Based on Impedance Spectroscopy Measurement and Partial Least-Squares Regression.

During spirit beverages production, the distillate is divided into three parts: the head, the heart, and the tail. Acetaldehyde and ethanol are two key markers which allow the correct separation of distillate. Being toxic, the elimination of the head part, which contains a high concentration of acetaldehyde, is crucial to guarantee the consumer's health and security. Plus, the tail should be separated from the heart based on ethanol concentration. Nowadays, online or in-line sensors for acetaldehyde monitoring during distillation do not exist, and the online sensors for alcohol monitoring, based on density measurement, remain expensive for producers. In this work, we demonstrate the development of distillation monitoring sensors based on electrical impedance spectroscopy (EIS) measurements, combined with PLS-R (partial least-squares regression) modeling. Four types of sensors are proposed and tested with wine-based distillates. Using PLS-R, the best correlations were found for one electrode, named "SpotsSym". With an R 2 up to 89.9% for acetaldehyde concentration prediction and an R 2 up to 86.8% for ethanol, the obtained results indicate the promising potential of the proposed approach. To our knowledge, this is the first report of sensors capable of simultaneously measuring ethanol and acetaldehyde concentrations. Furthermore, these sensors offer the advantages of being low cost and nondestructive. Based on these results, the development of an in-line distillation monitoring system is possible in the near future, providing a promising tool for spirit beverages producers.

Ni and Co-based catalysts supported on ITQ-6 zeolite for hydrogen production by steam reforming of ethanol

Ni and Co catalysts supported on ITQ-6 zeolite have been synthesized and evaluated in the steam reforming of ethanol (SRE). Catalysts were also characterized by means of N2 adsorption-desorption, XRD, H2-TPR, and H2-chemisorption. ITQ-6 containing Co (Co/ITQ-6) presented a higher conversion of ethanol and production of hydrogen than ITQ-6 containing Ni (Ni/ITQ-6). The lower size of the metallic cobalt particles shown in Co/ITQ-6 seems to be the major responsible of its higher catalytic performance. Regarding the reaction by-products (CO, CH4, C2H4O and CO2), Co/ITQ-6 showed the lowest selectivity at medium and high temperatures (773 and 873 K). At low reaction temperatures (673 K) the dehydrogenation reaction predominates in the Co/ITQ-6, what it is supported by the high concentration of acetaldehyde detected at this temperature. In the case of the Ni/ITQ-6 the main side reaction at 673 K seems to be the methanation reaction since large concentrations of methane are detected. Stability studies were also carried out showing lower deactivation of Co/ITQ-6 at large reaction times (24 h). Characterization of the exhausted catalysts after reaction showed the presence of coke in both catalysts. Nevertheless, Co/ITQ-6 presented the lowest coke deposition. In addition, Co/ITQ-6 exhibited the lowest metal sinterization, what could be also account for the lower deactivation exhibited by this sample. This fact could be related to the higher interaction between the cobalt metallic particles and the ITQ-6 support as the H2-TPR studies demonstrate.

Synthetic Activity of Recombinant Whole Cell Biocatalysts Containing 2-Deoxy-D-ribose-5-phosphate Aldolase from Pectobacterium atrosepticum.

In nature 2-deoxy-D-ribose-5-phosphate aldolase (DERA) catalyses the reversible formation of 2-deoxyribose 5-phosphate from D-glyceraldehyde 3-phosphate and acetaldehyde. In addition, this enzyme can use acetaldehyde as the sole substrate, resulting in a tandem aldol reaction, yielding 2,4,6-trideoxy-D-erythro-hexapyranose, which spontaneously cyclizes. This reaction is very useful for the synthesis of the side chain of statin-type drugs used to decrease cholesterol levels in blood. One of the main challenges in the use of DERA in industrial processes, where high substrate loads are needed to achieve the desired productivity, is its inactivation by high acetaldehyde concentration. In this work, the utility of different variants of Pectobacterium atrosepticum DERA (PaDERA) as whole cell biocatalysts to synthesize 2-deoxyribose 5-phosphate and 2,4,6-trideoxy-D-erythro-hexapyranose was analysed. Under optimized conditions, E. coli BL21 (PaDERA C-His AA C49M) whole cells yields 99 % of both products. Furthermore, this enzyme is able to tolerate 500 mM acetaldehyde in a whole-cell experiment which makes it suitable for industrial applications.

Breath octane and acetaldehyde as markers for acute respiratory distress syndrome in invasively ventilated patients suspected to have ventilator-associated pneumonia.

RationaleThe concentration of octane and acetaldehyde in exhaled breath has good diagnostic accuracy for acute respiratory distress syndrome (ARDS). We aimed to determine whether breath octane and acetaldehyde are able to distinguish the presence and absence of ARDS in critically ill patients suspected to have ventilator-associated pneumonia (VAP).MethodsThis is a secondary analysis of a prospective observational study into exhaled breath analysis using gas chromatography–time-of-flight mass spectrometry. Difference in the relative abundance of octane and acetaldehyde in exhaled breath was compared between patients with and without ARDS using the Mann–Whitney U-test and the association was quantified using logistic regression. The discriminative accuracy of octane and acetaldehyde, alone or in combination, was calculated using the area under the receiver operating characteristic curve (AUROCC).ResultsWe included 98 patients, of whom 32 had ARDS and 66 did not. The area under the acetaldehyde peak was higher in patients with ARDS (p=0.03), and associated with the presence of ARDS (OR 1.06 per 100 000 count change, 95% CI 1.02–1.13 per 100 000 count change; p=0.01). A combined model with octane and acetaldehyde showed a high specificity and low sensitivity (90% and 40.6%, respectively), with a low accuracy (AUROCC 0.65, 95% CI 0.53–0.78).ConclusionPatients suspected to have VAP with ARDS had a higher acetaldehyde concentration in exhaled breath than patients suspected to have VAP without ARDS. However, in this patient population, discrimination of these breath biomarkers for ARDS was poor, indicating the difficulty of translating diagnostic tests between clinical settings.

The thermal runaway analysis on LiFePO4 electrical energy storage packs with different venting areas and void volumes

With increasingly more electrochemical energy storage systems installed, the safety issues of lithium batteries, such as fire explosions, have aroused greater concerns. In this study, the thermal runaway behaviors of two different structures of lithium–iron-phosphate battery packs were compared. A fire explosion occurred in battery pack I, which had a small venting area and void volume, but battery pack II with a large venting area and the void volume kept safe. To explain these phenomena, a new experimental method coupling multiple measurements was proposed in this study to survey the velocity, composition, and temperature of venting gas. The venting gas velocity had two peaks, with its maximum value reaching about 270 m/s. Besides, the venting gas was mainly composed of hydrogen and carbon dioxide, accounting for around 30.33% and 38.86%, respectively. With the experimental data used as boundary conditions in a mathematical model, the diffusion behaviors of the venting gas within these two battery packs were derived. By comparing the flammable gas concentration with their lower explosion limits and upper limits, this study found that the high concentration of hydrogen and ethylene might bear the main responsibility for the fire explosion in battery pack I.

Inter-auricular distance: A morphological biomarker for ethylene production in the boot and coincidental grain loss of rice plant

Inter-auricular distance (IAD) has been often used for physical calibration of defects in panicle emergence of rice plants induced by stress-prone environments or cytoplasmic male sterility genetic factors slackening male gametogenesis. Information is scant on the physiological relationship inherent between IAD, panicle enclosure, and spikelet filling despite the wide phenotypic diversity of rice cultural types. In the present study, IAD extension and grain filling pattern in the panicle of the main shoot of rice cultivars contrasting for spikelet sterility were assessed concerning physiological factors like assimilate homeostasis, ethylene evolution, and expression of ethylene signal transducers genes at the anthesis stage of development. The panicle retention time was longer and the concentration and expression of ethylene and its transducer protein genes respectively, were higher in high sterile cultivars compared to low sterile ones. Spikelets subjected to a high concentration of ethylene for a longer time interval filled poorly because of infringement of starch synthesis in the post-anthesis stage of development. Alternatively, faster release of panicle by enhanced IAD extension shortened the exposure time and marginalized inhibitory effects of ethylene on grain filling. Rapid IAD extension and attenuation of boot ethylene production could be beneficial for male gametogenesis and grain filling.

Ethylene distribution and ventilation strategies of apple cold storage

Ethylene is a kind of plant hormone that may affect storage quality of fruit and corresponding ventilation strategies of cold storage. The purpose of this study was to explore the emission characteristics of ethylene and put forward ventilation strategies to reduce ethylene concentration. A real 230 t cold store for apples in Fufeng County of China was taken as the research object, Gas Chromatograph analysis (GC analysis) was applied to test ethylene concentration in the cold room, it was found that the indoor ethylene release rate peak appeared at 70 d. A 3-D, unsteady, incompressible and viscous numerical calculation model was developed and the component transport model was applied to numerically study the complicated phenomenon of heat transfer and mass transfer in the cold storage room. The results show that the ethylene concentration formed a tendency of diffusion from the apple zone to the air zone, and the highest ethylene concentration did not appear in the center of the apple zone, but appeared near the bottom of the apple zone. Furthermore, the air cooler was recommended to be running during ventilation for shorter ventilation time of 40 min and better temperature stability for cold storage.

Pseudomonas fluorescens Mannitol‐2‐Dehydrogenase as an NAD + Recycling Enzyme in the Conversion of Ethanol to Acetaldehyde

Bioethanol is predominantly produced by fermentation of corn feedstocks in the United States. In recent years, market saturation has reduced the value of ethanol, threatening the viability of bioethanol plants throughout the Midwest. The overall goal of this project is to develop enzymatic and catalytic methods for converting ethanol into higher value chemical derivatives that enhance the economic sustainability of bioethanol plants. Acetaldehyde has a market price 2.5 times greater than ethanol. Alcohol dehydrogenases may be used to oxidize ethanol to acetaldehyde, but they require the cofactor NAD+, which must be regenerated in a recycling reaction. In this study, we examined a mannitol-2-dehydrogenase from Pseudomonas fluorescens (PfM2DH) as a candidate recycling enzyme to regenerate NAD+. PfM2DH catalyzes the reversible, NADH-dependent reduction of fructose to mannitol. Fructose is a readily available substrate at bioethanol plants as it is derived from corn starches. The efficacy of PfM2DH in an industrial setting will depend on the effect temperature, time (enzyme durability), pH and potential inhibitors (high ethanol or acetaldehyde concentration) have on PfM2DH activity. We have purified PfM2DH using published methods and have investigated the factors above using continuous assays measuring NADH oxidation by UV-Vis spectrophotometry. We are currently developing methods to assay the coupled production of acetaldehyde by gas chromatography. Our results demonstrate that PfM2DH retains activity from pH 7.5 up to pH 9.0, which is valuable for coupling with alcohol dehydrogenases that have pH optimums between 8.0 and 9.0. PfM2DH shows modest inhibition by acetaldehyde and ethanol at high concentrations and retains activity at room temperature for several days. These data are guiding our design of coupled enzyme reactions to efficiently generate acetaldehyde as a higher value derivative of ethanol. The success of this project will lay the groundwork for the future industrial valorization of bioethanol.

Paternal Biomass Smoke Exposure in Rats Produces Behavioral and Cognitive Alterations in the Offspring.

Particular concern at the present stage is the health effects of wildfires’ smoke. The aim of the study was to determine the impact of paternal biomass-smoke exposure on offspring’s behavior and cognitive abilities. Male rats were exposed to biomass smoke for four hours/day, five days/week, for four weeks. Average concentration of carbon monoxide and particulate matter of 2.5 μm PM2.5 in the chamber during exposure were 28.7 ± 5.3 mg/m3 and 1.9 ± 0.5 mg/m3, respectively. At the same time, high concentrations of furfural and acetaldehyde were detected in the air environment of the exposure chambers. Offspring was obtained by mating of experimental males with untreated females, immediately after the end of the exposure and after 60 days (long-term period). Offspring were tested by using the Morris water maze and open field at three months of age. Male and female offspring born by mating immediately after exposure demonstrated decreased exploratory behavior, locomotor activity, and spatial navigation, as well as increased anxiety levels. Locomotor and exploratory activity in rats of both sexes from progeny obtained after long-term exposure to smoke had no statistically significant differences when compared to the control; however, the females showed a high level of anxiety and impaired cognitive functions. The recovery period after biomass-smoke intoxication, comparable in duration of spermatogenesis in rats, was an important factor in reducing the risk of developing central nervous system (CNS) disorders in offspring.

Pathogenesis and Persistence of Increased Epithelial Mucosubstances in the Nasal Airways of Rats and Mice Episodically Exposed to Ethylene.

Rats repeatedly exposed to high airborne concentrations of ethylene develop eosinophilic rhinitis and mucous cell hyperplasia/hypertrophy (MCH) in nasal respiratory epithelium. Mechanisms underlying these lesions are not well understood to inform occupational exposure guidelines. In this study, we determined (1) the nasal histopathology in rats episodically exposed to ethylene, (2) the ethylene-induced nasal histopathology in similarly exposed mice, and (3) how innate lymphoid cells (ILCs) play a role in ethylene-induced MCH. Animals were exposed to 0 or 10,000 ppm ethylene, 6 h/d, 5 d/wk, for 2 weeks and sacrificed 1 day or 2 weeks postexposure. Others received three 2-week exposure blocks separated by 2-week intervals of no exposure. Episodic exposure was chosen to aid in distinguishing irritant from immune responses. Mucous cell hyperplasia/hypertrophy was induced by ethylene in both species. Rats developed a mild, but transient, eosinophilic rhinitis. Mucous cell hyperplasia/hypertrophy was transient in mice, but persistent in rats. Increases in epithelial mucosubstances after 2 weeks of exposure were only present in ILC-sufficient mice, but not in ILC-deficient mice suggesting that ILCs play a role in MCH and overexpression of genes associated with mucus production/secretion. These findings in animals suggest that inhaled ethylene does not act as a sensitizing agent and will not induce allergen-like nasal airway disease.

Glyphosate and nickel differently affect photosynthesis and ethylene in glyphosate-resistant soybean plants infected by Phakopsora pachyrhizi.

Nickel (Ni) and glyphosate (Gl) are able to reduce the symptoms of Asian soybean rust (ASR), caused by Phakopsora pachyrhizi, in soybean. However, their combined effects on the energy balance and ethylene metabolism of soybean plants infected with this fungus has not been elucidated. Therefore, the effects of Ni, Gl, and the combination of Ni + Gl on ASR development, photosynthetic capacity, sugar concentrations, and ethylene concentrations in plants of a Gl-resistant cultivar, uninfected or infected with P. pachyrhizi, were investigated. Inoculated plants supplied with Ni had the highest foliar Ni concentration in all the treatments. Gl had a negative effect on the foliar Ni concentration in Ni-sprayed plants. The ASR severity was reduced in plants sprayed with Ni and Gl. Carotenoid and chlorophyll concentrations were higher in inoculated Ni, Gl, and Ni + Gl plants than in control plants. Based on the chlorophyll a fluorescence parameters, the photosynthetic apparatus of the control inoculated plants was damaged, and the least amount of energy was directed to the photochemistry process in these plants. The reduced capacity of the photosynthetic mechanism to capture light and use the energy absorbed by photosystem II in inoculated plants was reflected in their reduced capacity to process CO2 , as indicated by the high internal CO2 concentrations and low rates of net carbon assimilation. The low sugar concentrations in inoculated plants from the control treatment were linked to their reduced photosynthetic capacity due to the high ASR severity. In uninfected plants, the ethylene concentration was not affected by Ni or Gl, while the ethylene concentration decreased in inoculated plants; this decrease was more pronounced in plants from the control treatment than in treated inoculated plants. In conclusion, this study sheds light on the role played by both Ni and Gl in ASR control from a physiological perspective. Soybean plants exposed to Ni and Gl were able to maintain high ethylene concentrations and photosynthetic capacity during the P. pachyrhizi infection process; as a result, these plants consumed less of their reserves than inoculated plants not treated with Ni or Gl.

Involvement of ethylene in wheat resistance to infection by Pyricularia oryzae

Considering wheat as an important staple food crop worldwide and the great impact of blast, caused by Pyricularia oryzae, to decrease yield, this study aimed to investigate the involvement of ethylene on wheat susceptibility to blast based on its basal and induced levels in plant tissues. Plants from cultivars BRS Guamirim and BRS 220 (susceptible and partially resistant to blast, respectively) were non-sprayed or sprayed with Ethrel (0.0001 M) 24 h before inoculation with P. oryzae. Blast severity was higher on ethylene-sprayed plants regardless of the cultivar. High foliar ethylene concentration for inoculated plants from cultivars BRS Guamirim and BRS 220 was associated with an increase in leaf tissues susceptibility to blast. Ethylene was synthesized on inoculated leaves regardless of ethylene spray. Expressions of the genes 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) 1, ACS 2, and ACC oxidase (ACO) were lower for plants from cultivar BRS 220 which showed lower blast severity. Peaks on the expressions of ACS 1 and ACS 2 genes for plants from cultivar BRS Guamirim non-sprayed with ethylene were stimulated by P. oryzae infection. PR-1 gene expression enhanced in response to ethylene spray indicating an increase in wheat resistance to blast mainly for plants from cultivar BR 220. In general, peroxidases, phenylalanine ammonia lyases and poliphenoloxidases activities were kept stable from 48 to 96 h after inoculation (hai) but seemed to be affected by both ethylene spray and fungal infection. For inoculated and ethylene-sprayed plants from cultivar BRS 220, a peak for chitinase activity occurred at 96 hai while β-1,3-glucanases activity was kept higher for inoculated plants from 48 to 96 hai. β-1,3-glucanases activity enhanced upon P. oryzae infection but was not potentiated by ethylene. The concentration of photosynthetic pigments decreased for inoculated plants from cultivar BRS Guamirim due to high blast severity. In conclusion, ethylene biosynthesis on wheat leaves was triggered by P. oryzae infection and host defense responses were activated.

Polymorphism and form II – form I transformation in Ziegler-Natta isotactic 1-butene-ethylene copolymers having a multiblock molecular structure

A study of the crystallization behavior and kinetics of form II-form I transition in isotactic butene-ethylene copolymers (iPBEt) prepared with Ziegler-Natta catalyst with ethylene concentration in the range 9–44 mol% is presented. The samples have been separated with boiling solvents in different fractions containing chains with different ethylene concentration. Crystallization of form II from the melt is observed in each fraction even at high ethylene concentration, up to nearly 16 mol%. For higher ethylene content the samples do not crystallize from the melt but still crystallize during aging at room temperature in form I′. The comparison with the crystallization behavior of iPBEt copolymers prepared with homogeneous metallocene catalysts, characterized by a random distribution of ethylene units, has shown that the form II-form I transformation in Ziegler-Natta copolymers is much slower than in metallocene copolymers having the same ethylene concentrations and for the metallocene copolymers a low concentration of ethylene units of nearly 6 mol% is sufficient to prevent crystallization from the melt of form II. This indicates that in the chains of Ziegler-Natta iPBEt copolymers the regular butene sequences interrupted by the ethylene units are much longer than those of the chains of copolymers prepared with metallocene catalysts of the same ethylene concentration, giving further evidence of the multiblock structure of Ziegler-Natta iPBEt copolymers.

Pyrolysis of Waste Palm Oil in the Presence of Steam

This work ranges among studies dedicated to valorization of waste vegetable oils. In the present study, the pyrolysis of the waste palm oil was performed in presence of steam, in a tubular pyrolysis reactor operated in a continuous mode. The raw used in the pyrolysis reaction is the frying waste palm oil and the reactor was operated at high temperature (575 -625°C) and reaction time of 72s and 144s, at a steam: oil ratio of 0.1 -0.2. Valuable compounds such as olefins (ethylene, propylene) were obtained in the process, and they can be used further as raw materials in the chemical and petrochemical industry. The gaseous product resulted contained high ethylene and propylene concentrations: 18.89 - 25.5% and 13.33-15.05%, respectively. Based on the experimental results, some linear equations were developed to predict the products yields, and the coefficients of the model were statistically verified. These equations can serve at scaling up the pyrolysis process. Keywords: Steam cracking, vegetable oil pyrolysis, yield prediction, mathematical model