Sap Samples Research Articles

Detection of Oxytetracycline in Citrus Phloem and Xylem Saps Using Europium-Based Method.

Oxytetracycline (OTC) has been used for the control of several plant diseases and was recently approved for the control of Huanglongbing, the citrus greening disease. Huanglongbing is caused by the phloem limited ‘Candidatus Liberibacter asiaticus’. Determination of OTC in the xylem and phloem of citrus plants is of great interest as they are the main routes of translocation in citrus. In addition, the determination of the level of OTC in the phloem sap is necessary for the control of the ‘Ca. L. asiaticus’ pathogen, which resides in the phloem. Herein, we demonstrated that the level of OTC in the citrus phloem and xylem saps obtained using the centrifugation method can be successfully measured using the europium (Eu) method directly or with cleanup by solid-phase extraction (SPE). Recovery of OTC from spiked sap samples purified by solid-phase extraction (SPE) was higher than 90%, while recovery from saps without SPE cleanup were nearly 100%. The ‘Ca. L. asiaticus’-infected leaf and phloem sap samples showed higher inhibition of the fluorescence intensity of the OTC standard compared to non-infected control leaf and phloem samples. In agreement with this finding, the levels of phenols and flavonoids in ‘Ca. L. asiaticus’-infected leaves were higher than those controls and were shown to interfere with the Eu method. Therefore, the SPE cleanup step only improved OTC recovery from leaf samples containing the interfering compounds. The Eu method was then used to determine OTC levels in the phloem and xylem sap of OTC-treated plants, and the results were similar whether measured directly or after SPE. Visualization under ultraviolet light (400 nm) showed the presence of OTC in citrus xylem and phloem saps with and without the use of SPE.

A needle-type micro-sampling device for collecting nanoliter sap sample from plants.

In plant research, measuring the physiological parameters of plants is vital for understanding the behavior and response of plants to changes in the external environment. Plant sap analysis provides an approach for elucidating the physiological condition of plants. However, to facilitate accurate sap analysis, a sampling device capable of collecting sap samples from plants is required. In this paper, a minimally invasive, needle-type micro-sampling device capable of collecting nanoliter (~ 91nL) quantities of sap from plants is described. The developed micro-sampling system showed great reproducibility (3%) in experiments designed to assess sampling performance. As a proof of concept, sap samples were collected continuously from target plants with the micro-sampling system, and the dynamic changes in potassium ions, plant hormones and sugar levels inside plants were analyzed. The results demonstrated the feasibility of the micro-sampling device and its potential for developing a measurement system for plant research in the future.

Evaluation of Established Methods for DNA Extraction and Primer Pairs Targeting 16S rRNA Gene for Bacterial Microbiota Profiling of Olive Xylem Sap.

Next-generation sequencing has revolutionized our ability to investigate the microbiota composition of diverse and complex environments. However, a number of factors can affect the accuracy of microbial community assessment, such as the DNA extraction method, the hypervariable region of 16S rRNA gene targeted, or the PCR primers used for amplification. The aim of this study was to assess the influence of commercially available DNA extraction kits and different primer pairs to provide a non-biased vision of the composition of bacterial communities present in olive xylem sap. For that purpose, branches from “Picual” and “Arbequina” olive cultivars were used for xylem sap extraction using a Scholander chamber device. The DNA extraction protocol significantly affected xylem sap bacterial community assessment. That resulted in significant differences in alpha (Richness) and beta diversity (UniFrac distances) metrics among DNA extraction protocols, with the 12 DNA extraction kits evaluated being clustered in four groups behaving differently. Although the core number of taxa detected by all DNA extraction kits included four phyla, seven classes, 12 orders, 16 or 21 families, and 12 or 14 genera when using the Greengenes or Silva database for taxonomic assignment, respectively, some taxa, particularly those identified at low frequency, were detected by some DNA extraction kits only. The most accurate depiction of a bacterial mock community artificially inoculated on sap samples was generated when using the PowerPlant DNA extraction kit, the combination of 799F/1193R primers amplifying the hypervariable V5–V7 region, and the Silva 132 database for taxonomic assignment. The DESeq2 analysis displayed significant differences among genera abundance between the different PCR primer pairs tested. Thus, Enterobacter, Granulicatella, Prevotella, and Brevibacterium presented a significant higher abundance in all PCR protocols when compared with primer pair 799F/1193R, while the opposite was true for Pseudomonas and Pectobacterium. The methodological approach followed in this study can be useful to optimize plant-associated microbiome analysis, especially when exploring new plant niches. Some of the DNA extraction kits and PCR primers selected in this study will contribute to better characterize bacterial communities inhabiting the xylem sap of olives or other woody crop species.

The effect of arginine addition on chemical and antioxidant properties of coconut sap during heating

Arginine contains positive charged ends that are suitable to bind molecules with negative charge like carbonyl groups of reducing sugar in coconut sap. This research aimed to determine the effect of various arginine concentrations on chemical and antioxidant properties of coconut sap during the heating process. A 2.5 L of coconut sap was added with 0.4; 0.8 and 1.2 mM arginine and heated with an open process until the temperature of sap reached 118 °C. Fifty grams of sap samples were collected in the temperature of 80, 100 and 118 °C during heating treatment. The results showed that the variation of arginine concentration did not significantly affect water content, reducing sugar, total sugar, and sucrose of coconut sap samples. Coconut sap added with 0.4 mM showed the highest pH during heating. The highest of free amino acid content was shown on coconut sap added with 0.8 mM arginine at the end of heating temperature. The 0.8 mM of arginine concentration and the sap temperature of 100 °C were the optimum condition to obtain the highest DPPH radical scavenging activity i.e. 69.93%, while the chelating activity of coconut sap added with 0.4 mM was significantly higher than other treatments (34.42%).

Growing medium soluble carbon and nitrogen influence xylem sap and soluble solid contents in greenhouse cucumber fruits

Compelling evidence recently demonstrated that plants can take up nitrogen (N) as organic molecules. Yet, very little research addressed this issue in the context of organic horticulture, where N is provided as organic residues. Organic N and carbon (C) transported from roots to shoots could contribute significantly to the plant C and N accumulation. We posited that the type (organic or mineral) and amount of N fertilization affect the soluble organic N and C content of the growing medium, in turn influencing xylem sap N and C and fruit soluble solids content (SSC). To test this hypothesis, we collected growing medium, xylem sap, and fruit samples in a greenhouse cucumber crop grown in a peat-based growing medium and fertilized with organic (blood and feather meals) or mineral (ammonium nitrate) N fertilizers. The organic N source reduced growing medium concentrations of soluble mineral and organic N relative to the mineral source through microbial immobilization. Xylem sap C and N were positively linked to the soluble C and N contents of the growing medium, contributing to higher fruit SSC. A causal model is proposed, in which 62.6% of the variance observed in fruit SSC is explained by variation in mineral soluble N and soluble organic C in the growing medium and dissolved organic C and amino acids in xylem sap. Our results provide in situ indications that organic molecules in the growing medium are taken up by cucumber plants and contribute to fruit soluble solids in a context relevant to greenhouse horticulture.

Assessment of the Physico-chemico and Microbiological changes during Nipa (Nypa fruticans) Sap Fermentation collected from different sites in Cagayan province, Philippines

Background/Objectives: Sap from Nypa fruticans are used as feedstock for a bioethanol national program to establish a sustainable and productive village-scale bioethanol industry. The study aimed to establish the physicochemical, microbiological, and molecular characteristics of nipa sap. Methods/Statistical Analysis: Nipa sap samples were collected from three sampling sites at different fermentation time. Physico-chemical parameters such as pH, titratable acidity, and total soluble solids were determined and statistically analyzed using One-way Analysis of Variance and mean ± SD values. Molecular approaches were used to profile and identify yeast species naturally residing in the sap during fermentation and assess the genetic diversity of nipa palm in selected sampling locations. Findings: Sampling site and fermentation time significantly affect the levels of pH, titratable acids, and total soluble solids in the sap samples. Sugar concentration in nipa sap is affected by sampling site: as the sampling site nears the river, the amount of sugars become significantly greater. Molecular studies revealed that among the 12 isolates obtained, five of them (Y24S1, Y48S1, Y72S1, Y24S2, and Y24S3) showed 100% similarity to strain of Pichia occidentalis, three (Y48S2, Y48S3, and Y72S3) were similar (100%) to a strain of Saccharomyces cerevisiae (YPDW9), and the other two isolates (Y72S1 and Y48S3A) were identical to Naganishia randhawae strain HBUMO6885 and Tremellales sp. LM523 respectively with a 100% similarity. PCR amplification of their trnL–trnF cpDNA genome, BLAST and phylogenetic analyses reveals that all nipa plant samples were similar to Nypa fruticans. Applications: The generated information on the effect of sampling site on sugar content of nipa sap samples could be good input in selecting expansion sites for the establishment of nipa plantations. Furthermore, the identified yeast strains can be used as inoculant or starter culture to improve fermentation. Keywords: Physico-chemical parameter; yeasts molecular profiling; nipa sap fermentation; phylogenetic analysis; genetic diversity

Metabolomics reveals chemical changes in Acer saccharum sap over a maple syrup production season.

Maple syrup, made by boiling the sap of Acer saccharum, is an important agriculture commodity in eastern Canada and New England. Although the collection season is relatively short, a rich progression in the sensory qualities of maple syrup can occur throughout the season. A risk associated with maple syrup production at the end of a season is the development of off-flavors that result in syrup with little to no commercial value. Maple syrup producers in Canada and the USA call this ‘buddy syrup’. In this study, sugar maple (Acer saccharum) sap was collected in sequential samples through the harvest season from stands across Ontario. Metabolomics analysis of the sap samples was performed by high-resolution mass spectrometry. This revealed an evolution of the chemical composition, mainly occurring 30 days prior to leaf emergence. The major chemical constituent of maple syrup, sucrose, decreased sharply in late season sap, driven by microbial activity. The alditol mannitol increased in late season sap to concentrations ≥2 mg/mL and is likely an indicator of the start of photosynthesis. Amino acids, notably methionine and asparagine were present in higher amounts in late season sap. Non-targeted analysis revealed a series of related compounds that contained quaternary ammonium moieties including choline, hercynine, trigonelline, glycine betaine and carnitine increased in late season sap. These classes of compounds could act as methyl donors during the heating/evaporation of sap into syrup, affecting taste. Based on descriptions of the nature of buddy syrup and an extensive literature on flavors in foods, the amino acids methionine and asparagine were found as likely precursors to the compounds responsible for buddy syrup.

Microbial Succession and Chemical Characteristics in Fermentation of Ambonese Arrack (Sopi), Traditional Beverage from Maluku

Ambonese arrack is one of the traditional fermented beverage product in Maluku, Indonesia. The microbiological research of this beverage that is processed using coconut sap as raw material has never been done before. The research aimed to analyze the microbial succession and chemical characteristics during fermentation of Ambonese arrack. The sample of coconut sap was taken from traditional producer in Mahia village, Ambon. The dominant microbes in the fermentation of Ambonese arrack were Pichia polymorpha and Kloeckera javanica. The highest numbers of these two microbes was obtained after 15 hours fermentation (9.6 log Cfu/mL and 9.9 Cfu/mL, respectively). The sugar content decreased from 593.3 mg/L to 474.3 mg/L, whereas ethanol content increased from 0.0018 g/L to 0.0100 g/L. The pH value decreased from 4.70 to 3.10. The research has isolated indigenous microbes in Ambonese arrack fermentation which was considered as novelty. The bacteria that play a role in fermentation can be used as a starter in the fermentation of various beverage products, especially Ambonese arrack. The results of this research can improve the quality of this fermentation product in the future.

Xylem sap phosphorus sampling using microdialysis-a non-destructive high sampling frequency method tested under laboratory and field conditions.

For a better understanding of plant nutrition processes, it is important to study the flux of nutrients within plants. However, existing xylem sap sampling methods are typically destructive and do not allow for repeated, highly frequent measurements of nutrient concentration. In this paper, we present a novel use of microdialysis (MD) for characterizing xylem sap phosphate (PO43-) concentration as a possible alternative to destructive sampling. First, MD probes were tested under laboratory conditions in vitro, in a stirred solution test, and in vivo, using beech tree stem segments. Exponential decline in the relative recovery (RR) with an increasing MD pumping rate allows for determining an optimal sampling interval (i.e., the maximum amount of sample volume with the minimum required concentration). The RR changed only minimally, with a change in the simulated sap flow velocity during the in vivo stem segment test. This suggests that MD can be applied over a range of naturally occurring sap flow velocities. Differences in the ionic strength between the xylem sap and the perfusate pumped through the MD did not influence the RR. Then, MD was successfully applied in a 24h field campaign in two beech trees of different ages and allowed for in situ assessments of the diurnal variation of PO43- concentration and (together with xylem flow measurements) flux variability in living trees. Both beech trees exhibited the same diurnal pattern in PO43- concentrations with higher concentrations in the younger tree. The xylem PO43- concentration measured with MD was in the same order of magnitude as that received through destructive sampling in the younger tree. The MD probes did not show a decline in RR after the field application. We showed that MD can be applied to capture the PO43- concentration dynamics in the xylem sap with bihourly resolution under field conditions.

Mikrofiltrowany koncentrat soku brzozowego jako innowacyjny, trwały środek spożywczy o wysokiej wartości odżywczej

Introduction. The forest environment becomes an increasingly popular place of obtaining raw materials, and one of the most promising product is birch sap. The market for bottled birch sap in Poland is monotonous, relying exclusively on pasteurized, acidified and sweetened drinks. A chance to change this situation is to develop a birch sap concentrate obtained by reverse osmosis. It has a sweet taste desired by consumers and particularly high content of minerals, unfortunately it has short shelf life. Aim. The purpose of this work was to develop an effective method of extending the shelf life of birch sap concentrate without the need for pasteurization and chemical interference in the composition. In this way, the new product will be formulated with the potential to compete effectively with synthetic dietary supplements. Material and methods. Birch sap was obtained using drilling technique and continuous collection from the trunks of birch trees (Betula pendula Roth.). The sap was concentrated using reverse osmosis apparatus of our construction, obtaining a sugar concentration, expressed by Brix refractometric extract, equal 2.6° and a dry weight of 2.557%. Microfiltration of birch sap concentrate was carried out under sterile conditions using 0.22, 0.45 and 0.8 μm filters. In the monthly storage test, the measurements were carried out every three days, the optical density parameter was determined. Results. The microfiltration of birch sap concentrate was effective only when 0.22 and 0.45 μm filters were used, no turbidity was observed in the monthly storage test. The samples filtered with a filters with pore diameter of 0.8 μm, became cloudy at analogues time of the test as the samples of non-microfiltered birch sap concentrate, but the turbidity was lowered. Conclusions. The microfiltered birch sap concentrate is characterized by extended shelf life without the addition of chemical substances and without the use of pasteurization process, as well as improved taste compared to the initial raw material without the addition of sweeteners. Thanks to the combination of reverse osmosis and microfiltration, the natural character of the sap is largely preserved. The obtained product has a chance to appear on the food market as an innovative foodstuff. Moreover, due to the high concentration of ions (e.g. zinc and manganese) the concentrate could become an interesting alternative to artificial supplements.

Corn microbial diversity and its relationship to yield.

This study aimed to identify possible relationships between corn (Zea mays L.) productivity and its endosphere microbial community. Any insights would be used to develop testable hypotheses at the farm level. Sap was collected from 14 fields in 2014 and 10 fields in 2017, with a yield range of 10.1 to 21.7 tonnes per hectare (t/ha). The microbial sap communities were analyzed using terminal restriction fragment length polymorphism (TRFLP) and identified using an internal pure culture reference database and BLAST. This technique is rapid and inexpensive and is suitable for use at the grower level. Diversity, richness, and normalized abundances of each bacterial population in corn sap samples were evaluated to link the microbiome of a specific field to its yield. A negative trend was observed (r = -0.60), with higher-yielding fields having lower terminal restriction fragment (TRF) richness. A partial least square regression analysis of TRF intensity and binary data from 2014 identified 10 TRFs (bacterial genera) that positively, or negatively, correlated with corn yields, when either absent or present at certain levels or ratios. Using these observations, a model was developed that accommodated criteria for each of the 10 microbes and assigned a score for each field out of 10. Data collected in 2014 showed that sites with higher model scores were highly correlated with larger yields (r = 0.83). This correlation was also seen when the 2017 data set was used (r = 0.87). We were able to conclude that a positive significant effect was seen with the model score and yield (adjusted R2 = 0.67, F[1,22] = 46.7, p < 0.001) when combining 2014 and 2017 data. The results of this study are being expanded to identify the key microbes in the corn sap community that potentially impact corn yield, regardless of corn variety, geographic factors, or edaphic factors.

Torulaspora nypae sp. nov., a novel yeast species isolated from nipa (Nypa fruticans Wurmb.) inflorescence sap in southern Thailand.

Two strains (YSP-384 and YSP-399), representing a novel Torulaspora species, were isolated from two nipa inflorescence sap samples collected in Trang province in the southern part of Thailand. The two strains had identical sequences of the D1/D2 domains of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) regions. The two strains were closest to Torulaspora maleeae CBS 10694T, but with 1.1 % nucleotide substitutions in the D1/D2 domains of the LSU rRNA gene and 5.2 % nucleotide substitutions in the ITS regions. Phylogenetic analysis based on the concatenated sequences of the ITS regions and the D1/D2 domains of the LSU rRNA gene supported that the two strains represented a distinct species in the genus Torulaspora. Some phenotypic characteristics of the two strains differed from T. maleeae including the two strains have ability to assimilate d-xylose, d-glucono-δ-lactone and melizitose, and inability to ferment maltose and raffinose, whereas T. maleeae has opposite results. Therefore, the two strains are described as representing a novel species, for which the name Torulaspora nypae sp. nov. was proposed.

A simple and high-throughput method for xylem sap collection.

Xylem is the most important route for root-to-shoot translocation of water, nutrients and signaling molecules. Although a number of studies have been performed using xylem sap, its collection requires special equipment and is usually low throughput. Here, we developed a simple and high-throughput method for the collection of both medium- (<1ml) and small- (<200μl) volume xylem sap samples. Using a rice Cd transporter mutant, we demonstrated that our method allows for the effective evaluation of xylem sap Cd concentrations.

Insights into the Rheological Behavior of Aqueous Dispersions of Synthetic Saponite: Effects of Saponite Composition and Sodium Polyacrylate

Synthetic saponite (Sap) easily delaminates in water to form a transparent sol and hydrogel with excellent rheological performance and is thus widely used in paints, cosmetics, and nanomaterials. The thixotropic property of Sap hydrogels is heavily dependent on the nature of Sap and the external electrolyte and polyelectrolyte; yet, details on the relationship between rheological behaviors of saponite hydrogels and Sap composition and polyelectrolyte remain unclear. In this work, thixotropic rheological behaviors of a series of synthetic Sap hydrogels, with and without added sodium polyacrylate polyelectrolyte (NaPA), were investigated. The Sap samples, with a Si/Al molar ratio from 5 to 25, were successfully synthesized using hydrothermal methods and characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. The rheological performances of aqueous Sap dispersions and particle sizes and ζ-potentials of Sap were measured. The results showed that the crystallinity of the Sap increased with an increasing Si/Al molar ratio. All Sap samples, with the exception of the Sap with a Si/Al molar ratio of 5, dispersed well in water (3 wt %) to form hydrogels. The rheological behaviors of the hydrogels were related to the chemical composition and the layer charge of the Sap. The Sap with a Si/Al molar ratio of 25 had higher viscosity due to improved delamination. The addition of the NaPA, an anionic polyelectrolyte, into the hydrogels decreased the viscosity and altered the thixotropic properties such that the hydrogel becomes a sol. The addition of NaPA facilitated the dispersion and delamination of Sap, because under the electric field of negatively charged Sap particles in the hydrogel, the anionic NaPA was instantaneously polarized and thereby entered the hydration layer of the Sap particles.

Fabrication of a label-free electrochemical immunosensor for direct detection of Candidatus Phytoplasma Aurantifolia

A novel label-free electrochemical immunosensor was fabricated for selective and sensitive detection of Candidatus Phytoplasma Aurantifolia (CPA), the main factor of witches broom diseases, in tree sap samples. CPA antibody was immobilized on a thiol terminated surface of a gold electrode modified by gold nanoparticles; the surface was then activated by mixture of N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride (EDC) and N-HydroxySuccinamide (NHS). Scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed for surface characterization. All the electrochemical measurements of CPA were accomplished based on the [Fe(CN)6]3−/4− solution response as the standard redox probe. CPA detection was carried out using square wave voltammetry (SWV) technique, at frequency of 20 Hz and amplitude of 0.1 V. In order to reach the maximum efficiency in performance of the immunosensor, Anti-CPA 1 mg mL−1, pH 7.4 and the incubation time of 45 min were selected as optimized experimental conditions. According to the calibration curve data, the obtained linear range was 0.005 to 100 μg mL−1, with limit of detection (LOD) of 1.5 ng mL−1, which was lower than the value reported for ELISA method applied for CPA detection. The immunosensor demonstrated adequate selectivity and stability besides; there was no significant interference observed from other probable protein based components in the real sample matrix.

IL-13–induced intestinal secretory epithelial cell antigen passages are required for IgE-mediated food-induced anaphylaxis

Food-induced anaphylaxis (FIA) is an IgE-dependent immune response that can affect multiple organs and lead to life-threatening complications. The processes by which food allergens cross the mucosal surface and are delivered to the subepithelial immune compartment to promote the clinical manifestations associated with food-triggered anaphylaxis are largely unexplored. We sought to define the processes involved in the translocation of food allergens across the mucosal epithelial surface to the subepithelial immune compartment in FIA. Two-photon confocal and immunofluorescence microscopy was used to visualize and trace food allergen passage in a murine model of FIA. Ahuman colon cancer cell line, RNA silencing, and pharmacologic approaches were used to identify the molecular regulation of intestinal epithelial allergen uptake and translocation. Human intestinal organoid transplants were used to demonstrate the conservation of these molecular processes in human tissues. Food allergens are sampled by using small intestine (SI) epithelial secretory cells (termed secretory antigen passages [SAPs]) that are localized to the SI villous and crypt region. SAPs channel food allergens to lamina propria mucosal mast cells through an IL-13-CD38-cyclic adenosine diphosphate ribose (cADPR)-dependent process. Blockade of IL-13-induced CD38/cADPR-dependent SAP antigen passaging in mice inhibited induction of clinical manifestations of FIA. IL-13-CD38-cADPR-dependent SAP sampling of food allergens was conserved in human intestinal organoids. We identify that SAPs are a mechanism by which food allergens are channeled across the SI epithelium mediated by the IL-13/CD38/cADPR pathway, regulate the onset of FIA reactions, and are conserved in human intestine.

Effect of the new high vacuum technology on the chemical composition of maple sap and syrup

BackgroundTechniques used to produce maple syrup have considerably evolved over the last decades making them more efficient and economically profitable. However, these advances must respect composition and quality standards as well as authenticity of maple products. Recently, a new and improved high vacuum technology has been made available to producers to achieve higher sap yields. The aim of the present study was therefore to evaluate the effect of this new system on the yield of sap and on the sap and syrup chemical composition. ResultsSap yield was monitored during the 2013 and 2014 seasons for high vacuum collection systems (25–28 InHg) and compared to the control systems (20 InHg). Samples of sap and syrup were also collected for chemical analysis. During the 2013 season, a sap volume of 166.19 L/tap was recorded at 25 InHg vacuum level while the control vacuum level permitted to collect 139.47 L/tap, corresponding to a yield increase of 19.2 %. The following season, a yield increase of 38.2 % was measured when control and 28 InHg vacuum levels were compared with 118.06 and 163.13 L/tap, respectively. Results on the pH, color, flavor, minerals, sugars, organic acids, total polyphenols, total nitrogen, abscisic acid and auxin (Indol-3-acetic acid) showed no major differences between high vacuum technology and the control with values remaining within ranges previously published. ConclusionResults showed that a use of high vacuum systems increased sap yield and had no major impact on the quality and purity of maple sap and syrups compared with the control systems.

INVESTIGATION OF EXPLOSION SAFETY OF DC POLYMER SURGE ARRESTERS 3.3 KV FOR TRACTION NETWORK OF RAILWAY TRANSPORT

In the testing laboratories of Ukraine, there is no high-voltage equipment of the necessary energy for testing surge arresters for explosion safety, which does not allow to estimate this indicator at the stage of development of prototypes. In view of this test, the polymer prototypes of the DC surge arresters in polymer case (SAp) 3.3 kV were tested under the operating conditions of the equipment of the operating substation with short-circuit currents of 8.3 kA and a current time of 0.02 seconds, close to the recommended by Standard of IEC 60099-4:2014 values. 8 samples of surge arresters were tested. A sample of the surge arrester was mounted on one of the metal supports at a height of 5.5 m located in the substation and connected to the 3.3 kV traction substation buses through disconnectors and a high-speed switch. After the short-circuit breaker was closed through a column with a pre-punched or shunted copper wire varistor, a short-circuit current flowed to form an electric arc inside the arrester samples. During the tests video samples were recorded using a video recorder installed in close proximity to the test sample. The frame of the SAp samples in which the varistors were enclosed was performed either by winding the fiberglass tape on a varistor column, or from rods arranged in the form of a squirrel cage, or in the form of a fiberglass tube with a hole for gas ejection during a short circuit inside the SAp. The destruction of the hull occurred without scattering of the fragments in seven cases from the eight samples tested. In seven samples, a local rupture of the silicone shell occurred in the varistor zone, a gas ejection and an arc discharge occurred through this gap. The exception was sample No. 2, made by a continuous winding of a glass-banding tape on a varistor column, in which, during the explosion, the upper electrode exploded with the simultaneous expansion of fragments of the varistor in a radius of 3-5 m. Due to the white smoke accompanying the explosion, it was not possible to fix on the frame whether the arc output from the case to the outside, despite the fact that on the next frame (in 33 ms.) the arc was no longer fixed. In the tests of eight of the presented designs, none of them ignited the hull. If the tests were carried out on the surge arresters assembled with pre-punched varistors (electrothermal breakdown), the varistors during the tests split, remaining inside the frame. From the action of the arc in the contact zone of the aluminum electrodes with varistors, a deep burn-out of the electrodes was observed, in some cases, the burnup was up to 7 mm deep and up to 8 mm wide. If the varistors were shunted by a copper wire, they remained intact. If the varistors were shunted by a copper wire, they remained intact und melting and burning out a part of the aluminum electrodes in the area of connection with the copper wire were smaller sizes. The samples showed a completely satisfactory ability to withstand large pulse currents without dispersing dangerous fragments for personnel and surrounding equipment. However, polymer designs, the frame of which is made by continuous winding, require reinforcement of the connection zone of the carcass with electrodes to exclude the break-out of electrodes during the accumulation of gases during a short circuit inside the shell of the SAp. For such designs, an additional test for mechanical strength in the longitudinal direction with a predetermined norm is required in the acceptance test program.

Effects of Fermentation Duration on Bio-Ethanol Yield from Cell Sap of Selected Palm Species in Nigeria

It is believed that feedstock for biofuel production should not constitute any form of competition in terms of food security, therefore the study considered the bioethanol potential comparison of a particular breed of palm commonly referred to as nypa palm (Nypa fruticana) which is usually of environmental concern in mangrove vegetation zones with two other species namely the raphia palm (Raphia hookeria) and oil palm (Ealasis guinesis) which are considered as having economic value. A catalysed fermentation process was carried out using Saccharomyces cerevisiae over a periods of 24, 48, 72, 96, 120, 144 and 168 hrs at room temperature. At peak production the bioethanol from Nypa palm specie had 38.6 and 37.9% more ethanol concentration than the oil and raffia palms respectively. The biomas concentration in the nypa palm sap sample after the fermentation period were about 26.7 and 29.5% higher than what was obtainable in the oil and raffia palms. The fermentation efficiency for the three samples was observed to be 90.2, 84.5 and 87.3% for nypa, oil and raffia palms respectively. It can be concluded from results obtained that nypa palm offered the highest bioethanol production potential, thus could offer a good source of non-competitive feedstock for renewable energy production in Nigeria where the plant is usually viewed as an environmental nuisance and in some extreme cases maritime hazard.Keywords— Alcoholmeter, Bioethanol, Fermentation Efficiency, Feed Stock, Nypa Palm

Changes in the Elemental and Metabolite Profile of Wheat Phloem Sap during Grain Filling Indicate a Dynamic between Plant Maturity and Time of Day.

The long distance transport of Fe and Zn in the phloem sap of wheat (Triticum aestivum L.) is the key route for seed supply, due to wheat having a xylem discontinuity. To date, our knowledge is limited on Fe and Zn homeostasis in the phloem sap during the reproductive and grain filling stages. With the use of aphid stylectomy to collect samples of phloem sap, we explored maturity and morning versus afternoon (within-day) changes in nutrient and metabolite profiles. Phloem exudate was collected from a wheat breeding line, SAMNYT16, at three times during the grain filling period and at both midday and mid-afternoon. There were significant changes in the concentration of Mg, K, Fe and Zn during the course of grain loading and there were also significant within-day differences for Fe and K concentrations in the phloem exudate during the early phases of grain development. We found that, for K and Fe, there was an increase of 1.1- and 1.4-fold, respectively, for samples taken prior to midday to those from mid-afternoon. There was also a significant decrease in K, Fe and Zn phloem sap concentration of 1.5-, 1.4- and 1.1-fold, respectively, from the start of peak grain loading to the end of grain loading. Of the 79 metabolites detected within samples of phloem exudate, 43 had significant maturity differences and 38 had significant within-day variability. Glutamine was found to increase by 3.3–5.9-fold from midday to mid-afternoon and citric acid was found to decrease by 1.6-fold from the start of grain loading to the end of grain loading. These two metabolites are of interest as they can complex metal ions and may play a role in long distance transport of metal ions. The work presented here gives further insight into the complex composition of the phloem sap and variability that can occur during the day and also with increasing maturity.