Neutral Substances Research Articles

Influence of acid-base dissociation equilibria during electromembrane extraction.

Electromembrane extraction is affected by acid-base equilibria of the extracted substances as well as coupled equilibria associated with the partitioning of neutral substances to the supported liquid membrane. A theoretical model for this was developed and verified experimentally in the current work using pure 2-nitrophenyl octyl ether as supported liquid membrane. From this model, extraction efficiency as a function of pH can be predicted. Substances with log P<0-2 are generally extracted with low efficiency. Substances with log P>2 are generally extracted with high efficiency when acceptor pH<pKaH - log P. Twelve basic drug substances (2.07<log P<6.57 and 6.03<pKaH <10.47) were extracted under different pH conditions with 2-nitrophenyl octyl ether as supported liquid membrane and fitted to the model. Seven of the drug substances behaved according to the model, while those with log P close to 2.0 deviated from prediction. The deviation was most probably caused by deprotonation and ion pairing within the supporting liquid membrane. Measured partition coefficients (log P) between 2-nitrophenyl octyl ether and water, were similar to traditional log P values between n-octanol and water. Thus, the latter have potential for pKaH - log P predictions.

Characterization of precipitation in the background of atmospheric pollutants reduction in Guilin: Temporal variation and source apportionment

Rainfall samples were collected from three observation sites in Guilin from 2013 to 2017, and the chemical composition characteristics of precipitation and the contribution made by different ion sources were analyzed when atmospheric pollutants levels were reduced. The results showed that acid gas emissions and atmospheric pollutant concentrations continued to decline during the study period. However, the change in the volume-weighted mean pH at the three sites suggested that acid rain pollution was not alleviated and began to deteriorate after 2015. The continuing downward trend for alkaline neutralizing ions (Ca2+, NH4+) in precipitation indicated that the reduction in alkaline neutralizing substances in the atmosphere was an important factor that led to the deterioration in acid rain across Guilin. The principal component analysis and spearman correlation analysis indicated five sources of ions in precipitation. Quantitative assessment of these five sources indicated that fossil fuel combustion contributed the most ions concentration in precipitation at the three sites, followed by agriculture, terrestrial (crustal) sources, marine sources, and biomass burning. Long-distance airflow might affect the acidity, the electrical conductivity (EC), and ion concentrations in precipitation across Guilin. The airflow trajectory from the west and southeast directions corresponded to higher acidity and ion concentrations. According to the current air pollution control strategy planned by Guilin, reducing atmospheric coarse particles and NH3 at the same time may potentially lead to further deteriorations in acid rain contents. Therefore, Guilin needs to develop more reasonable pollution prevention measures that synergistically control atmospheric pollutants and acid rain pollution.

Development of the tape pH indicator acid-basic from açai pulp extract

Euterpe oleracea Mart. known as acai, it is a palm of bacaceous fruit, distributed throughout Brazil in states such as Amazonas, Pará, Maranhão, Rondônia and Tocantins. The objective of this work was to produce an acid-base indicator strip from the hydroalcoholic extract of the pulp of Euterpe oleracea Mart. to determine acidity by colorimetric method, also seeking to develop in a simple, fast and low cost, being an alternative way to be used in teaching Chemistry in experimental practical classes with the subject covered in Inorganic Functions in Teaching: Elementary, Middle and Higher. The methodology used was carried out in stages: (i) obtaining the acai pulp from the fruits of the açaizeiro, (ii) obtaining the extract from the pulp of Euterpe oleracea Mart., (iii) building a pH scale (0- 14), (iv) obtaining a pH paper from the hydroalcoholic extract, (v) identification of acidic and basic substances in everyday use with both the extract and the pH indicator paper, (vi) determining the acetic acid content in commercial vinegars, and (vii) a comparison of the results obtained from% acetic acid, both with the synthetic indicator (phenolphthalein) and with the natural indicator. Through the tests with the tape and with the pulp extract of Euterpe oleracea Mart. satisfactory results were obtained. Thus, the pH tape and the Euterpe oleracea Mart. pulp extract identified the acidic, basic and neutral substances of everyday life, showing an alternative for teaching with practical experimental chemistry classes, being financially viable, and exploring an application of Euterpe oleracea Mart. pulp. as forest treasure for future industrial applications, such as the production of a pH indicator strip.

THE SIBERIAN LARCH GROUP COMPOSITION AND ACID NEEDLES AT DIFFERENT VEGETATION PERIODS

The research results of the Siberian larch needle extractives are presented in paper. The content of extractive substances from green and yellow needles extracted by organic solvents with different polarities is determined. It is found out that the double increase of the yellow needle extractive substances content soluble in hydrocarbon extractant is observed, whereas it is decreased by 30 per cent when extracted with propan-2-ol. The group composition of needle extracts derived from isopropanol extract by petroleum ether is determined. The neutral substances content in both needle collections is practically the same, although the yellow needles contain less acid “bound” in the form of esters. There is a high content of waxes in the needles, which mainly consist of secondary nonacosanol-10 alcohol.&#x0D; The composition of free and “bound” acids in Siberian larch needles of different vegetation periods is established. The needles are dominated by groups of higher unsaturated C-18 fatty acids. Resin acids are represented by isopimaric acid (isopimaric and sandaracopimaric) and abietic acids: abietic, dehydroabietic and levopiric acids. In yellow needles, the content of dehydroabietic acid is increased quadrupled and the hydroxy acids are identified: 15-hydroxyabietic acid and 15-hydroxyhydroabietic acid. The tri- and tetraenic C-20 acids are identified among higher fatty acids.

Characterizing property and treatability of dissolved effluent organic matter using size exclusion chromatography with an array of absorbance, fluorescence, organic nitrogen and organic carbon detectors.

In this study, size exclusion chromatography with an array of absorbance, fluorescence, organic nitrogen and organic carbon detectors was used for characterizing property and treatability of effluent organic matter (EfOM) from 12 wastewater treatment plants. According to their apparent molecular weight (AMW), EfOM fractions were assigned to biopolymers (>20 kDa), humic substances that comprise sub-fractions of humic-like acids (HA-I & HA-II, 2.3-7.0 kDa) and fulvic-like acids (FA, 1.5-2.3 kDa), building blocks (0.55-1.5 kDa) and low molecular weight neutral substances (<550 Da). The fractions of biopolymers and low molecular weight neutral substances didn't show humic-like fluorescence, while the fractions of HA-II, FA and building blocks usually had signatures of both humic-like and protein-like fluorescence. Humic substances generally contributed the largest proportion of dissolved organic carbon and nitrogen (DOC & DON) in effluents. Coagulation removed EfOM fractions following the order of biopolymers > HA subfraction > FA subfraction > building blocks, while little removal of protein-like fluorescence in HA-II and FA subfractions was detected. Anion exchange treatment could effectively reduce DOC and DON concentrations; the sequence of the treatment efficiency was humic substances > biopolymers > building blocks. Increasing O3 doses caused DOC and DON of EfOM to be gradually transformed from large AMW fractions into small AMW fractions, while chromophores and fluorophores in HA subfractions were relatively more refractory than those in the other fractions. Size exclusion chromatography with multiple detectors are suggested to be an informative technique for estimating treatability of EfOM by advanced wastewater treatment processes.

Application of coagulation-ultrafiltration-nanofiltration in a pilot study for Tai Lake water treatment.

In this study, the inline coagulation was combined with ultrafiltration and nanofiltration (UF-NF) in a pilot study for Tai Lake water treatment. The results showed that the combination process was very effective for Tai Lake water treatment in terms of organic removal and membrane fouling control. With inline coagulation, no irreversible membrane fouling was observed for either UF or NF at fluxes of 65-90 and 22-26L/(m2 hr), respectively. The membrane foulants were analyzed, and the results indicated that the low molecular weight fractions in the feed were main membrane fouling contributors for both UF and NF, where hydrophilic substances and proteins, as well as neutral substances and humic acids with polycarboxyl groups, contributed significantly to UF and NF membrane fouling, respectively. Compared with direct UF-NF filtration without coagulation, the coagulants could aggregate organic micromolecules for cake formation. With inline coagulation, the moving flocs could generate shear stress to scrub the membrane surface for fouling control of UF. Moreover, with inline coagulation, the organics removal efficiency could be further increased by 10%-20%. With NF, the permeate had a TOC concentration of less than 0.5mg/L, satisfying the drinking water quality. Therefore, the coagulation-UF-NF is very useful for Tai Lake water treatment. PRACTITIONER POINTS: Inline coagulation-UF-NF for Tai Lake Water treatment is implemented. Inline coagulation can aggregate hydrophilic substances to reduce membrane fouling. Moving flocs produce shear stress for fouling control of UF-NF. Superior quality of permeate is achieved with the combined coagulation-UF-NF process.

Assessment of functional relationships between acids and neutral compounds of canabinoids in modern monoecious varieties of Cannabis sativa L.

Aim. The research was aimed at determining the correlation between neutral substances and acids in varieties of Cannabis sativa L. Methods. Taking into account lability and isomerization of cannabinoids under the influence of various factors, the TLC method was used for preserving the naturally formed ratio of cannabinoids without disturbing their qualitative and quantitative interrelations. Results. In the hemp variety YuSO 1 excluded from breeding work to reduce the content of neutral substances, varieties of French selection – Fedora 17 and Futura 77 with relatively high content of cannabinoids and with varieties of hemp Zolotonis’ky 15 and Viktoriya with reduced or absent content of neutral substances, high interdependence between neutral compounds and acids was determined. In the varieties of hemp YuSO 31, Hlyana, Hlukhivs’ky 46 insufficient selections for reducing the content of neutral substances led to a violation of the formed relationships between acids and neutral substances. Correlation interdependence was negative. Conclusions. The determined correlation between neutral substances and acids in cannabis varieties indicates the existing biologically determined dependence between them taking into account natural acids.&#x0D; Keywords: THC, CBD, CBN, CBDА, THCA.

Triterpene alcohols and sterols of Siberian larch (Larix sibirica Ldb.) needles

The composition of triterpene alcohols and sterols in the fraction of Siberian larch (Larix sibirica Ldb.) conifer needles is considered in paper. The needles areextracted with propan-2-ol; resinous substances are extracted with petroleum ether (40–70°C);substances extracted with petroleum ether are divided into free acids and neutral substances. Neutral substances are separated in a silica gel column; eluent - petroleum ether supplemented with diethyl ether. The isolated esters fraction is hydrolyzed with potassium hydroxide in ethanol, and the “bound” acids are separated from unsaponifiable substances. Non-saponified substances are separated by chromatography into 5 fractions of phytosterols, the alcohol components of esters. The fractions are acetylated; the alcohol acetates are separatedonsilica gel with added silver nitrate. The isolated compounds was identified by NMR and GC-MS methods. Cycloartenol (6.82%, hereafter based onunsaponifiable substances), 24-methylenecycloartanol (6.75%), citrastadienol (7.69%), sitosterol (7.18%), cycloevcalenol (0.09%) are identified, obtussifoliol (0.01%), 24-methylenelophenol (0.10%), methyllophenol (1.84%) and campesterol (0.33%).

Residual chemical oxygen demand (COD) fractionation in bio-treated coking wastewater integrating solution property characterization

The refractory nature of residual COD in bio-treated coking wastewater (BTCW) creates barriers for its further treatment and reclamation. It is necessary to fractionate the residual COD in BTCW associated with characterization of solution properties. In this paper, a stepwise process composed of membrane filtration, coagulation, adsorption and ozonation was proposed to fractionate residual COD in the BTCW, in which the COD was stepwise reduced to near zero. In addition, the correlation between COD and water quality indexes as well as solution properties were discussed together with a safety assessment of the water quality. Results showed that the residual COD fractionation percentage contributed by suspended solids, colloids, dissolved organics and reductive inorganic substances in the BTCW was 43.7%, 22.1%, 26.2% and 4.9%, respectively. By stepwise fractionating of these substances, the residual COD was reduced from 168.8 to 5.2 mg L−1, and the UV254 value decreased from 1.90 to 0.15 cm−1. In addition, the particle size of the dominant substances contributing to the residual COD was smaller than 450 nm. Among these substances, the hydrophobic fraction accounted for 78.66% (in the term of TOC). Three-dimensional excitation-emission matrix (3D-EEM) analysis showed that hydrophobic neutral substances (HON) were the main fluorescence constituent in the BTCW, which was highly removable by adsorption. The residual COD after adsorption was mainly composed of reductive inorganic substances. Apart from pursuit of high COD removal rates, more emphasis should be given to the removal of toxic COD. Correlations were observed between the residual COD and water quality indicators as well as solution properties, providing a guideline for optimized removal of residual COD in the BTCW. In summary, these results gave a referential information about the nature of residual COD in the BTCW for the selection of advanced treatment technologies and the management of water quality safety.

Chemosensory Event-Related Potentials in Response to Nasal Propylene Glycol Stimulation.

Propylene glycol, also denoted as 1.2 propanediol (C3H8O2), often serves as a solvent for dilution of olfactory stimuli. It is supposed to serve as a neutral substance and has been used in many behavioral and electrophysiological studies to dilute pure olfactory stimuli. However, the effect of propylene glycol on perception and on neuronal responses has hitherto never been studied. In this study we tested by means of a threshold test, whether a nasal propylene glycol stimulation is recognizable by humans. Participants were able to recognize propylene glycol at a threshold of 42% concentration and reported a slight cooling effect. In addition to the threshold test, we recorded electroencephalography (EEG) during nasal propylene glycol stimulation to study the neuronal processing of the stimulus. We used a flow olfactometer and stimulated 15 volunteers with three different concentrations of propylene glycol (40 trials each) and water as a control condition (40 trials). To evaluate the neuronal response, we analyzed the event-related potentials (ERPs) and power modulations. The task of the volunteers was to identify a change (olfactory, thermal, or tactile) in the continuous air flow generated by the flow olfactometer. The analysis of the ERPs showed that propylene glycol generates a clear P2 component, which was also visible in the frequency domain as an evoked power response in the theta-band. The source analysis of the P2 revealed a widespread involvement of brain regions, including the postcentral gyrus, the insula and adjacent operculum, the thalamus, and the cerebellum. Thus, it is possible that trigeminal stimulation can at least partly account for sensations and brain responses elicited by propylene glycol. Based on these results, we conclude that the use of high propylene glycol concentrations to dilute fragrances complicates the interpretation of presumed purely olfactory effects.

Citizen Science Double Blind Testing.

Citizen Science Double Blind Testing Ian Faulkner Soutar I write articles for the Elephant Journal magazine about health issues under the name Ian Faulkner. Normally double blind studies, in which both the participants and researchers don’t know who is receiving a particular intervention, are only attempted by corporations who can afford the testing. Thus the subject matter tested needs to relate directly to profitable products that the corporation paying for the study needs to sell. As a result, simple health solutions involving inexpensive supplements rarely received double blind testing. I have written a number of health-related articles and get a lot of feedback from other people experimenting with health concepts. Using supplemental boron to mitigate arthritis is a good example. It is easy to use, inexpensive and very effective. Yet it does not get properly tested because there is no profit in it for pharmaceutical corporations. For myself, I have suffered from arthritis since I was 23. I was born in 1949. By 2010, I could not walk a few blocks without great pain in my feet and hips. I read accounts that in Australia the use of boron for arthritis was discovered in about 1968 and that many cases of arthritis just disappeared when 9 milligrams per day of boron was added to the diet. I tried it out and within 3 months I was almost completely cured of arthritis. At the University of Victoria in Mechanical Engineering, we have a club whose members have tried boron supplements to treat arthritis. It worked very well for several of us who tried it. Of course, this is not a real study but it did prevent suffering in our group. It seemed to work in about 80% of cases. I wrote an article about boron and arthritis in the Elephant Journal. You can read the details by searching for “Ian Faulkner” at the magazine: http://elephantjournal.com. This simple solution has never been subjected to double blind studies because there is no profit in it. In the process of answering letters from readers on health solutions, it has been suggested by several readers that we could easily build a simple double blind testing system on the internet. It would take only a small team to carry out a large double blind study using the following method: Boron in a Citizen Science Double Blind Study 1. Experimentation is carried out using boron in the form of borax. The element boron is a good example to test. Borax (sodium tetra-borate) is [End Page 4] known to have almost the same toxicity as table salt. It was used in Australian hospital studies in the 1960s. 2. The participants in the study are part of a club, which agrees to self-experiment, knowing the risks. This eliminates the need for an ethics committee approval. 3. Samples of a boron supplement and a placebo are prepared by volunteers. 9 milligrams of boron are contained in the active capsules whereas a neutral substance such as sugar is placed in the placebo capsules. Three months of pills fill each sample bottle. 4. A number coding system on the bottles distinguishes boron from the placebo. 5. A second group of volunteers mails out the samples, along with a record of what number code was associated with the bottles. These volunteers do not know the number coding system. They send the samples to a third set of volunteers, the participants of the study. 6. A third group of volunteers, the participants in the study, receive the samples and participate in the study by taking one capsule a day for 3 months. Research to date from Australia shows that it takes 3 months or less to see results depending on age. It is therefore known that a 3-month study is sufficient. 7. After 3 months, software such as “Survey Monkey” is used to run a survey on the participants of the study. Questions are used to evaluate health effects. 8. Finally, the results are analysed comparing the participants known to have used the placebo vs. those who were known to have used boron. This kind of study is very inexpensive to do. It does not have an...

Application of Dual-Cyclodextrin Systems in Capillary Electrophoresis Enantioseparations.

The enantioseparation of acidic and neutral compounds can be successfully achieved in capillary electrophoresis (CE) using dual-cyclodextrin (CD) systems. This chapter describes how to separate the enantiomers of acidic or neutral substances using dual-CD systems made up of a negatively charged CD derivative, i.e., sulfobutyl-β-CD or carboxymethyl-β-CD, in combination with a neutral one, namely heptakis(2,3,6-tri-O-methyl)-β-CD. An acidic compound (carprofen) and a weakly acidic drug (pentobarbital) were selected as model compounds.

Water-soluble components in rainwater over Xi'an in northwest China: Source apportionment and pollution controls effectiveness evaluation

Rainwater samples were collected to investigate the water-soluble species levels and their sources at a semi-arid urban site of Xi'an, China, during 2015. The precipitation samples were analyzed for pH, electric conductivity (EC), ionic species (Na+, K+, NH4+, Ca2+, Mg2+, F−, Cl−, NO3−, and SO42−), and water-soluble organic carbon and nitrogen (WSOC and WSTN). The annual volume-weighted mean (VWM) of pH and EC values were 6.50 and 46.9 μS cm−1, respectively. The total ionic concentrations in rainwater varied widely, ranging from 121.9 to 2448.2 μeq L−1 with an annual VWM of 686.4 μeq L−1. SO42− was the largest contributor to anions while Ca2+ was the most important cation. SO42− and NO3− levels decreased in a large scale by comparing with prior study in six years ago. Moreover, the total wet depositions flux of water-soluble inorganic nitrogen (sum of NH4+-N and NO3−-N) and SO42--S were reduced by 54.5 and 81.1% in 2015 compared with 2009, respectively. The results indicated that the pollution controls during the past years were more effective over Xi'an. The average concentrations of water-soluble organic carbon and total nitrogen (WSOC and WSTN) were 2.9 and 3.9 mg L−1. The water-soluble organic nitrogen was the dominant component in WSTN. The neutralization factor showed that NH4+ and Ca2+ were the dominant neutralization substances in the rainwater, whereas the effects of Mg2+, K+ and Na+ were negligible. The enrichment factor analysis indicated that SO42− and NO3− were mainly originated from anthropogenic sources, while Ca2+ was associated with terrestrial sources. Source apportionment by a positive matrix factorization receptor model showed that the anthropogenic emissions were the largest contributor to SO42− (61.9%), NO3− (65.3%), and NH4+ (70.5%), followed by crustal sources (14.9, 21.3, and 18.4%) and biomass burning (13.8, 12.1, and 6.8%). For the major cations of Ca2+, crustal source was the dominant contributor (75.6%), followed by biomass burning (14.6%).

Ion-Transfer Voltammetry at a Water/1,2-Dichloroethane Interface Using Photoionization by Ultraviolet Irradiation: Detection of Cation Radicals of p-Phenylenediamine Derivatives.

We have attempted to detect electrically neutral substances by ion-transfer voltammetry at an interface between two immiscible electrolyte solutions (ITIES), such as an interface between water and 1,2-dichloroethane (a W/DCE interface), by irradiating the interface with ultraviolet light (200 - 300 nm). In the present work, while considering the facts that p-phenylenediamine derivatives are soluble in DCE, but insoluble in water, and that cation radicals of the derivatives are fairly stable in various media, we photoionized the derivatives in a DCE phase by ultraviolet irradiation, and after that carried out ion-transfer voltammetry at a W/DCE interface. As a result, we could successfully observe ion-transfer waves of cation radicals of the derivatives from the W to DCE phase. Namely, the cation radicals are generated in the DCE phase by ultraviolet irradiation, and subsequently distributed into the W phase. In addition to these ion-transfer waves, we also found that facilitated proton-transfer waves by the derivatives were shifted to a more negative potential region after ultraviolet irradiation, because of hydrogen chloride formed from photodecomposition of DCE by ultraviolet irradiation.

Acidic Wet Deposition in Bandung City Indonesia

Acidic deposition (acid rain) has been known to cause negative impact to environment. Measurement of rain chemical composition was done in March to August 2016 to investigate temporal variation of atmospheric deposition in Bandung City. Rainwater samples are collected at four sampling sites. The chemical properties of the rain determined were pH and ionic concentrations of SO42-, NO3-, Cl-, Ca2+, Mg2+, Na+, K+ and NH4+. The rainwater was typically acidic with the range of mean pH between 5.29 – 5.56 and mean electric conductivity value range between 16.37 – 19.96 μS/cm. Temporal variation showed higher SO42+, NO3+ and NH4+ concentration in August when rainfalls were the lowest (214.88 mm). Similar temporal variation for the mean pH (5.98) and electric conductivity (25.36 μS/cm) in August. Ca2+ highest concentration was observed in June. Generally, the the major component of precipitation chemistry were SO42- and NO3-, Ca+ and NH4+, for anion and cations, respectively. The largest proportions of the total anions in all sampling sites was SO42- ranged from 32% (Lembang) to 37% (Buah Batu) followed by NO3- (13 – 15%) and and Cl- (4 – 7%). For cations, NH4+ dominated with proportion ranged between 21 – 27% and subsequently Ca2+ (13 – 19%) and followed by Na+, Mg+, K+ and H+. The Neutralizing Factor (NF) results reveal that Ca2+ and NH4+ are the dominant neutralization substances in the rainwater. However it should be noted that reduced nitrogen (NH4+) act as mobile nitrogen that further will acidify the environment, particularly to soil ecosystem downstreams.

The Anomalous Influence of Spectral Resolution on Pulsed THz Time Domain Spectroscopy under Real Conditions.

We have studied the spectral resolution influence on the accuracy of the substance detection and identification at using a broadband THz pulse measured under real conditions (at a distance of more than 3 m from a THz emitter in ambient air with a relative humidity of about 50%). We show that increasing spectral resolution leads to manifestation of small-scale perturbations (random fluctuations) in the signal spectrum caused by the influence of the environment or the sample structure. Decreasing the spectral resolution allows us to exclude from consideration this small-scale modulation of the signal as well as to detect the water vapor absorption frequencies. This fact is important in practice because it allows us to increase the signal processing rate. In order to increase the detection reliability, it is advisable to decrease the spectral resolution up to values of not more than 40% of the corresponding spectral line bandwidth. The method of spectral dynamics analysis together with the integral correlation criteria is used for the substance detection and identification. Neutral substances such as chocolate and cookies are used as the samples in the physical experiment.

Progress in the Studies of Precipitation Chemistry in Acid Rain Areas of Southwest China

The precipitation data for nine sites in the acid rain area of southwest China were analyzed. The data included pH and the concentrations of major ions (Cl-, SO42-, NO3-, Ca2+, NH4+, Mg2+, K+, and Na+). SO42- and NO3- were the main anions, whereas Ca2+ and NH4+ were the main cations in the precipitation. The concentrations of acidic ions, alkaline ions, and total ions in this area were significantly higher than those reported in southeast China, but much lower than those in northern China. About 58% of the total precipitation has a pH value ranging from 4.5 to 5.6. According to the correlation of acidic and alkaline ions as well as the results of the neutralization factor, the rainwater in this area has been neutralized. Ca2+ and NH4+ are the dominant neutralization substances in rainwater. Comparisons of pH and the main ion components with other areas showed that rainfall neutralization in this area was stronger than that in southeast China but poorer than that in northern China. Calculation of enrichment factors for rainwater components relative to soil and seawater indicated that Ca2+ and Mg2+ mainly originated from terrestrial sources and SO42- and NO3- were mostly attributed to the anthropogenic activities in this area. In addition, approximately 99.7% of Ca2+ and 84.0% of Mg2+ were attributed to terrestrial sources and were closely related to the widespread distribution of carbonate rocks in the southwest of China.

Ascorbic Acid-A Potential Oxidant Scavenger and Its Role in Plant Development and Abiotic Stress Tolerance.

Over-production of reactive oxygen species (ROS) in plants under stress conditions is a common phenomenon. Plants tend to counter this problem through their ability to synthesize ROS neutralizing substances including non-enzymatic and enzymatic antioxidants. In this context, ascorbic acid (AsA) is one of the universal non-enzymatic antioxidants having substantial potential of not only scavenging ROS, but also modulating a number of fundamental functions in plants both under stress and non-stress conditions. In the present review, the role of AsA, its biosynthesis, and cross-talk with different hormones have been discussed comprehensively. Furthermore, the possible involvement of AsA-hormone crosstalk in the regulation of several key physiological and biochemical processes like seed germination, photosynthesis, floral induction, fruit expansion, ROS regulation and senescence has also been described. A simplified and schematic AsA biosynthetic pathway has been drawn, which reflects key intermediates involved therein. This could pave the way for future research to elucidate the modulation of plant AsA biosynthesis and subsequent responses to environmental stresses. Apart from discussing the role of different ascorbate peroxidase isoforms, the comparative role of two key enzymes, ascorbate peroxidase (APX) and ascorbate oxidase (AO) involved in AsA metabolism in plant cell apoplast is also discussed particularly focusing on oxidative stress perception and amplification. Limited progress has been made so far in terms of developing transgenics which could over-produce AsA. The prospects of generation of transgenics overexpressing AsA related genes and exogenous application of AsA have been discussed at length in the review.

Abietic acid isolated from pine resin (Resina Pini) enhances angiogenesis in HUVECs and accelerates cutaneous wound healing in mice

Ethnopharmacological relevanceResin known as Resina Pini is listed in the Korean and Japanese pharmacopoeias and has been used for treating skin wounds and inflammation. Resin is composed of more than 50% abietic acid and 10% neutral substances. ObjectiveIn the present study, the wound-healing effects of abietic acid and the possible underlying mechanism of action were investigated in various in vitro and in vivo models. Materials and methodsThe effects of abietic acid on tube formation and migration were measured in human umbilical vein vascular endothelial cells (HUVECs). Protein expression of mitogen-activated protein kinase (MAPK) activation was evaluated via Western blotting analysis. The wound-healing effects of abietic acid were assessed using a mouse model of cutaneous wounds. ResultsThe results showed that abietic acid enhanced cell migration and tube formation in HUVECs. Abietic acid induced significant angiogenic potential, which is associated with upregulation of extracellular signal-regulated kinase (ERK) and p38 expression. Additionally, 0.8μM abietic acid-treated groups showed accelerated wound closure compared to the controls in a mouse model of cutaneous wounds. ConclusionThe current data indicate that abietic acid treatment elevated cell migration and tube formation in HUVECs by the activation of ERK and p38 MAPKs. We suggest that abietic acid can be developed as a wound-healing agent.

Effect of soil contamination with fluorine on the yield and content of nitrogen forms in the biomass of crops

The research was based on a pot experiment, in which the response of eight species of crops to soil contamination with fluorine was investigated. In parallel, some inactivating substances were tested in terms of their potential use for the neutralization of the harmful influence of fluorine on plants. The response of crops to soil contamination with fluorine was assessed according to the volume of biomass produced by aerial organs and roots as well as their content of N-total, N-protein, and N-NO3−. The following crops were tested: maize, yellow lupine, winter oilseed rape, spring triticale, narrow-leaf lupine, black radish, phacelia, and lucerne. In most cases, soil pollution with fluorine stimulated the volume of biomass produced by the plants. The exceptions included grain and straw of spring triticale, maize roots, and aerial parts of lucerne, where the volume of harvested biomass was smaller in treatments with fluorine-polluted soil. Among the eight plant species, lucerne was most sensitive to the pollution despite smaller doses of fluorine in treatments with this plant. The other species were more tolerant to elevated concentrations of fluorine in soil. In most of the tested plants, the analyzed organs contained more total nitrogen, especially aerial organs and roots of black radish, grain and straw of spring triticale, and aerial biomass of lucerne. A decrease in the total nitrogen content due to soil contamination with fluorine was detected only in the aerial mass of yellow lupine. With respect to protein nitrogen, its increase in response to fluorine as a soil pollutant was found in grain of spring triticale and roots of black radish, whereas the aerial biomass of winter oilseed rape contained less of this nutrient. Among the analyzed neutralizing substances, lime most effectively alleviated the negative effect of soil pollution with fluorine. The second most effective substance was loam, while charcoal was the least effective in this respect. Our results showed the effect of soil contamination with fluorine on the yield and chemical composition of fluorine depended on the species and organ of a tested plant, on the rate of the xenobotic element and on the substance added to soil in order to neutralize fluorine.