Open Beaker Research Articles

Storage and persistence of a candidate fungal biopesticide for use against adult malaria vectors

BackgroundNew products aimed at augmenting or replacing chemical insecticides must have operational profiles that include both high efficacy in reducing vector numbers and/or blocking parasite transmission and be long lasting following application. Research aimed at developing fungal spores as a biopesticide for vector control have shown considerable potential yet have not been directly assessed for their viability after long-term storage or following application in the field.MethodsSpores from a single production run of the entomopathogenic fungi Beauveria bassiana were dried and then stored under refrigeration at 7°C. After 585 days these spores were sub-sampled and placed at either 22°C, 26°C or 32°C still sealed in packaging (closed storage) or in open beakers and exposed to the 80% relative humidity of the incubator they were kept in. Samples were subsequently taken from these treatments over a further 165 days to assess viability. Spores from the same production run were also used to test their persistence following application to three different substrates, clay, cement and wood, using a hand held sprayer. The experiments were conducted at two different institutes with one using adult female Anopheles stephensi and the other adult female Anopheles gambiae. Mosquitoes were exposed to the treated substrates for one hour before being removed and their survival monitored for the next 14 days. Assays were performed at monthly intervals over a maximum seven months.ResultsSpore storage under refrigeration resulted in no loss of spore viability over more than two years. Spore viability of those samples kept under open and closed storage was highly dependent on the incubation temperature with higher temperatures decreasing viability more rapidly than cooler temperatures. Mosquito survival following exposure was dependent on substrate type. Spore persistence on the clay substrate was greatest achieving 80% population reduction for four months against An. stephensi and for at least five months against Anopheles gambiae. Cement and wood substrates had more variable mortality with the highest spore persistence being two to three months for the two substrates respectively.ConclusionsSpore shelf-life under refrigeration surpassed the standard two year shelf-life expected of a mosquito control product. Removal to a variety of temperatures under either closed or open storage indicated that samples sent out from refrigeration should be deployed rapidly in control operations to avoid loss of viability. Spore persistence following application onto clay surfaces was comparable to a number of chemical insecticides in common use. Persistence on cement and wood was shorter but in one assay still comparable to some organophosphate and pyrethroid insecticides. Optimized formulations could be expected to improve spore persistence still further.

Influence of the Organic Species and Oxoanion in the Synthesis of two Uranyl Sulfate Hydrates, (H3O)2[(UO2)2(SO4)3­(H2O)]·7H2O and (H3O)2[(UO2)2(SO4)3(H2O)]·4H2O, and a Uranyl Selenate‐Selenite [C5H6N][(UO2)(SeO4)(HSeO3)

AbstractTwo uranyl sulfate hydrates, (H3O)2[(UO2)2(SO4)3(H2O)]·7H2O (NDUS) and (H3O)2[(UO2)2(SO4)3(H2O)]·4H2O (NDUS1), and one uranyl selenate‐selenite [C5H6N][(UO2)(SeO4)(HSeO3)] (NDUSe), were obtained and their crystal structures solved. NDUS and NDUSe result from reactions in highly acidic media in the presence of L‐cystine at 373 K. NDUS crystallized in a closed vial at 278 K after 5 days and NDUSe in an open beaker at 278 K after 2 weeks. NDUS1 was synthesized from aqueous solution at room temperature over the course of a month. NDUS, NDUS1, and NDUSe crystallize in the monoclinic space group P21/n, a = 15.0249(4) Å,b = 9.9320(2) Å, c = 15.6518(4) Å, β = 112.778(1)°, V = 2153.52(9) Å3,Z = 4, the tetragonal space group P43212, a = 10.6111(2) Å,c = 31.644(1) Å, V = 3563.0(2) Å3, Z = 8, and in the monoclinic space group P21/n, a = 8.993(3) Å, b = 13.399(5) Å, c = 10.640(4) Å,β = 108.230(4)°, V = 1217.7(8) Å3, Z = 4, respectively.The structural units of NDUS and NDUS1 are two‐dimensional uranyl sulfate sheets with a U/S ratio of 2/3. The structural unit of NDUSe is a two‐dimensional uranyl selenate‐selenite sheets with a U/Se ratio of 1/2. In‐situ reaction of the L‐cystine ligands gives two distinct products for the different acids used here. Where sulfuric acid is used, only H3O+ cations are located in the interlayer space, where they balance the charge of the sheets, whereas where selenic acid is used, interlayer C5H6N+ cations result from the cyclization of the carboxyl groups of L‐cystine, balancing the charge of the sheets.

The plasma wars: a history

The plasma wars: a history

저희석 유리구 용해법에 의한 암석시료 미량원소 분석법

Open beaker digestion method is routinely used as the sample preparation technique for trace element determination of rock samples by inductively coupled plasma mass spectrometry, With this method, however, dissolution of Zr and Hf is not always guaranteed especially when the samples contain refractory minerals. In this study, glass bead digestion technique was compared with conventional open beaker digestion technique for the sample preparation of three USGS rock standards such as AGV-2, BHVO-2, and G-3. Thirty trace elements including rare earth elements were analysed by ICP-MS and ICP-AES. There were no clear differences in analytical results for the AGV-2 and BHVO-2 standards between the two techniques, but Zr, Hf, Y, and middle- to heavy- rare earth element concentrations of the G-3 standard prepared by open beaker digestion technique were significantly lower than the recommended values. This can be attributed to the presence of refractory mineral zircon. On the contrary, all the analytical results of the G-3 standard prepared by glass bead digestion technique were in good agreement with the recommended values, indicating complete dissolution of zircon. The analytical results show that the volatile elements such as Pb and Zn were not lost during the preparation of glass bead. Low dilution glass bead digestion technique described here will be very helpful to enhance precision and accuracy of trace element analysis for geological samples containing refractory minerals.

Glycerol Mediated Low Temperature Synthesis of Nickel Nanoparticles by Solution Reduction Method

Phase pure Nickel nano-particles were synthesized by in-situ generation of nickel hydrazine hydrate complex (Ni-HH) followed by its decomposition in an alkaline glycerol medium. The synthesis can be performed in an open beaker with or without the use of surface protective reagents. By using the present method, Ni nano-particles can be prepared in large scale. The black nano-powders so-obtained were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infra-red (FTIR) spectroscopy and thermal analysis (TGA). XRD and SAED analysis revealed that the synthesized particles were pure crystalline nickel with FCC structure.

Aspects on the analysis of 210Po

There has been little development regarding analysis of polonium (Po) in environmental samples since the 1960ies. This is due to the straightforward spontaneous deposition of this element on silver (Ag), nickel (Ni) or copper (Cu) without any radiochemical separation. For many years, no radiochemical yield determinant was used and it was generally supposed that the yield was 100% after two depositions. Counting was often done using ZnS scintillation counter coupled to a photomultiplier tube. However, the use of the yield determinants 208Po and 209Po and the development of alpha spectrometry showed that the yield was lower. Furthermore, the tendency of Po to volatilize at low temperatures constrains the sample preparation techniques; dry-ashing cannot be used. But during the wet-ashing procedure, there are still some losses. The aim of this study was to evaluate the Po losses during wet-ashing by the use of a double-tracer technique. We have found that the losses were about 30% when open glass beakers were used and about 17% when the samples were digested in microwave oven. When long-necked bottles (Kjeldahl flasks) were used, a loss of about 20% was registered. It has also been observed that 210Pb to some extent is plating out together with its daughter nuclide Po during the electrochemical deposition. This will result in a systematic error since an unknown amount of supported 210Po will be produced from the 210Pb decay depending on the fraction of 210Pb being deposited on the disc and the waiting time between deposition and measurement of the sample. A further consequence of this is that in the assessment of the 210Pb content in the sample, very often the remaining liquid is stored after deposition for build-up of 210Po. Since some 210Pb is lost on the disc, the result for 210Pb will be too low. Both these systematic errors give rise to a too high 210Po/ 210Pb ratio. The fraction of 210Pb which is plating out has been assessed in this study for different matrices and is about 50–90%. During the measurement by solid state Si-detectors, some Po is evaporated in the vacuum conditions contaminating the detectors. Experiments have here been done by heating the discs after deposition which indicate that less Po is evaporated from Ag than from Ni. The losses from Ag are less than that from the other metals probably due to a deeper penetration into the surface of Po. We conclude that in most aspects, Ag is better to use than the other plating metals.

Dynamic multi-phase partitioning of decamethylcyclopentasiloxane (D5) in river water

The behaviour of decamethylcyclopentasiloxane (D5) in river water was evaluated by measuring concentration changes in open beakers. Effective values for the partition coefficient between organic carbon and water ( K OC) were derived by least-squares optimisation of a dynamic model which accounted for partitioning between the sorbed and dissolved phases of D5, and for losses via volatilisation and hydrolysis. Partial mass transfer coefficients for volatilisation were derived from model fits to controls containing deionised water. Effective values of log ( K OC) were between 5.8 and 6.33 (mean 6.16). These figures are higher than some other experimentally-derived values but much lower than those estimated from the octanol: water partition coefficient using single-parameter linear free energy relationships (LFERs). A poly-parameter LFER gave a predicted log ( K OC) of 5.5. Differences in partitioning are believed to be due to the nature of the organic matter present. The new value for effective K OC was employed in a simple model of D5 behaviour in rivers to ascertain the extent to which a higher affinity for organic carbon would depress volatility. The results suggest that despite the revised K OC value, volatilisation of D5 remains a significant removal mechanism in surface waters.

Suppression of salt weathering of porous limestone by borax-induced promotion of sodium and magnesium sulphate crystallization

Abstract The effects of borax on the crystallization of sodium and magnesium sulphate, two of the most damaging salts affecting porous stones, have been studied. Borax promotes the crystallization of mirabilite and inhibits epsomite crystallization in open glass beakers. The additive is preferentially adsorbed onto {140} mirabilite and {111} epsomite faces, thus acting as an effective habit modifier. In contrast, in the presence of a calcitic support (either Iceland spar single crystals or a porous limestone – a biocalcarenite) crystallization is promoted in the presence of borax, irrespective of the salt tested. Apparently, this is due to a high stereochemical affinity between borate molecules adsorbed (and/or co-precipitated) onto calcite, and mirabilite and epsomite crystals. Salt weathering tests using a biocalcarenite show a significant damage reduction upon borax addition to the saline solutions. Borax promotes the crystallization of both mirabilite and epsomite within the pores of the stone, reducing its porosity. Crystallization promotion favours nucleation at a low supersaturation, thereby resulting in very low crystallization pressure and minimal damage. Application of borax to porous limestones affected by mirabilite and/or epsomite crystallization could be a new means of suppressing salt weathering.

Heavy metals pollution in a sewage treatment oxidation pond and the receiving stream of the Obafemi Awolowo University, Ile Ife, Nigeria

This work centered on a 1-year evaluation campaign of point source pollution from a sewage treatment oxidation pond and its receiving stream. Water samples were collected from the sewage treatment oxidation pond and the receiving stream during July 2002 and June 2003. Concentrations of heavy metals were determined using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) after a triple acid digestion of samples using open beaker method. Generally, the results showed high levels of toxic metals such as Cd, Pb, As, Al, Cr, Mn, Co, and Fe in the influent and effluent samples as well as in the receiving stream. The annual mean concentration of metals in the sewage samples ranged from 11.90 to 16.05, 64.96 to 88.27, 38.91 to 76.35, 17.46 to 24.45 mug/L for Cd, As, Pb, Co, and 4.31 to 8.77, 1.71 to 2.45, 0.46 to 0.74 and 13.82 to 20.47 mg/l for Al, Cr, Mn and Fe, respectively; while in the receiving stream, the concentrations were between 6.89 to 10.45, 35.50 to 59.26, 22.85 to 35.94, 11.33 to 18.83 mug/l for Cd, As, Pb, Co, and 1.99 to 3.49, 1.35 to 2.08, 0.21 to 0.48, and 8.93 to 14.15 mg/l for Al, Cr, Mn and Fe, respectively. The discharge of the effluent from the sewage pond into the receiving stream has therefore led to increase in the concentrations of some heavy metals downstream, thus impacting the receiving stream negatively and could pose a serious health hazard to aquatic ecosystems and humans particularly for rural dwellers and peasant farmers downstream that utilize the water from the receiving stream for various domestic and agricultural purposes untreated.

Assessment of three major decomposition techniques for sample preparation during elemental analysis of granite rocks

Three main rock-decomposition techniques; microwave oven, open beaker acid and basic fusion were examined in an attempt to establish the most appropriate method for the decomposition of granite rocks for elemental analysis. Standard reference rock material NIM- SARM-I was dissolved using each of the digestion techniques and the solutions analyzed using an Inductively Coupled Plasma-Mass Spectrometery (ICP-MS) analytical system. Element concentration data for Al, Cr, Mn, Fe, Na, Mg, K, Ca, Ti,Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Y, Ba, La, Ce, Pr, Nd, Sm, Ru, Gd, Th, Dy, Ho, Lu, Pb, Cd, Th, and U were obtained. This work shows that no single decomposition technique can adequately attack all the mineral structures containing the elements as is evidence in the agreement or disagreement of the results when compared with the SARM-I certified values. Nigerian Journal of Physics Vol. 16(2) 2004: 15-20

Reductive Amination: A Remarkable Experiment for the Organic Laboratory

The synthesis of N-(2-hydroxy-3-methoxybenzyl)-N-p-tolylacetamide is a fast, simple three-step sequence that serves as a useful example of the reductive amination reaction for the organic chemistry laboratory. The first step is a spectacular solvent-free solid-solid reaction between ortho-vanillin and para-toluidine to synthesize an imine in quantitative yield. The imine is reduced to an amine in the second step by sodium borohydride. The amine is acetylated in the third step to form the solid amide in an overall yield of 90%. The entire sequence is performed in an open beaker in less than one hour.

Analysis of oxidized biodiesel by 1 H‐NMR and effect of contact area with air

Biodiesel is continuously gaining attention and significance as an alternative diesel fuel. An important issue facing biodiesel is fuel stability upon exposure to air due to its content of unsaturated fatty acids. Numerous factors influence the oxidative stability of biodiesel, and several methods for its assessment have been developed. In the present work, a defined amount of biodiesel (methyl soyate) was heated in open beakers, with the only difference being the size of the beaker, i.e. the surface area of the biodiesel exposed to air. Biodiesel oxidized in this fashion was analyzed by 1 H-NMR, kinematic viscosity and acid value. Acid values and kinematic viscosity increased with time and surface area. A previously developed 1 H-NMR procedure was used to evaluate the unsaturation and “residual” fatty acid composition. The amounts of saturated fatty acids determined by this method increased, with monounsaturated and diunsaturated species increasing and then decreasing with time. After “flash” (3 h, 165 7C) oxidation, NMR shows the greatest effect on saturates and compounds with two double bonds, the former increasing and the latter decreasing. The double bond originally located at D15 in 18:3 is largely retained, showing that other double bond positions in 18:3 are initially affected by oxidation. The methyl ester signal decreases, coinciding with the increase in acid value. An increasingly strong absorption was observed in the UV-VIS spectra. Increasing surface area accelerated oxidation and affected fatty acid composition.

Simple wetting method to reduce cyanogen content of cassava flour

Ten samples of cassava flour from Mozambique, Indonesia and Australia and one sample of gari from Mozambique were thoroughly mixed with water in the ratio 1:1.25. All the water was absorbed by the flour and the mixture was left in an open beaker at 30 °C. It was found that, providing that there was a reasonable amount of linamarase in the flour, the total cyanide content reduced about three-fold over 5 h. Addition of exogenous linamarase increased greatly the rate of breakdown of linamarin in the flour. There was no breakdown of linamarin from a gari sample at pH 4.2, but breakdown occurred when the pH was increased to 6 with buffer. The rationale for using this wetting method is that it is simple: the cassava flour is thoroughly mixed with water and allowed to stand in an open vessel for about 5 h, and then it is used for cooking. If the results in this brief paper are confirmed in the field and the method is acceptable to women, then it should decrease substantially the cyanide intake of those people in eastern, central and southern Africa who consume cassava flour, and thus reduce the incidence of cyanide poisoning and konzo.

Transfer Phenomena of Tritiated Water from Air to Water

Feasibility of the monitoring way of HTO in air to follow the tritium level in water contained in a small shallow beaker with open surface placed still in a room was discussed in this study. It is considered that the isotope exchange reaction between tritiated water in air and water in a beaker, the evaporation or condensation reaction of water at surface and the diffusion of tritium in water played the important roles in the tritium transfer phenomena through the air-water interface. Using the mass transfer coefficients obtained in the previous paper, change of tritium level in water contained in a shallow open beaker was numerically estimated and comparison with the experimental data showed good agreement. The estimated amount of tritium released from the facility with storage pools of spent fuels from a PWR power station using the method of this study showed good agreement with the observed value evaluated from the monitor of the power station

Hydrothermally synthesized and hot-pressed Bi 2(Te,Se) 3 thermoelectric alloys

Bi 2(Te,Se) 3 nanopowders have been synthesized by an aqueous chemical route in an open beaker at 70 °C for 72 h. The powders were hot-pressed under a pressure of 50 MPa at 250 °C for 15 min. X-ray diffraction and energy-dispersive analysis of X-rays show that both the powders and the hot-pressed samples are mainly composed of Bi 2(Te,Se) 3 and Te. Scanning electron microscopy observation shows that the crystallite size is smaller than 100 nm in the powders and the width of the polygonal prismatic rods is about 100 nm in the hot-pressed sample. The alloys were doped with SbI 3 before hot pressing. The SbI 3-doped sample shows a higher electrical conductivity and a lower Seebeck coefficient, indicating that SbI 3 is electrically actively incorporated into the alloys.

Response to different oxidation inhibitors for industrial lube base stocks

The response to antioxidants of different types (aminic, phenolic and sulphur‐based) has been evaluated for three base stocks intended for industrial lube production: a paraffinic solvent neutral, a hydrotreated naphthenic, and a naphthenic technical white oil. Furthermore, three different oxidation test methods were used: IP 280, DSC (in‐house), and ASTM D 1934 (open beaker). A statistical experimental design was used to evaluate the effects of the different inhibitors. For the naphthenic base stocks tested, the higher degree of refining, the better response to oxidation inhibitors. Since the test methods differ in severity, different inhibitors will be those giving the best effects in different tests. Severe tests require peroxide‐destroying inhibitors, while aminic or phenolic inhibitors show effects in milder tests. High oxidation stability can be achieved for various types of base stocks, naphthenic as well as paraffinic, if the right inhibitor system is chosen.

Headspace FT-IR Analysis of Rapeseed Oil Oxidation

Volatile compounds formed by oxidation of rapeseed oil at 60 °C in open beakers were studied as a function of time over 289 h. A direct inlet gas-phase FT-IR method was introduced and compounds indicating lipid oxidation were detected and quantified. The development of 1,3,5-trimethylbenzene, 2,4-hexadienal, 2-methyl-1,3-butadiene, 2-methyltetrahydrofuran, acetic acid, methyl cyclopentane, methyl hexanoate, n-butanal, n-hexanal, n-octanal, n-propanal, and trans, trans-2,4-heptadienal was followed. The results showed that gas-phase FT-IR is a potential method of fast analysis for monitoring oil quality. Headspace-gas chromatography-mass spectrometry (HS-GC-MS) was used for compound identification.

Effects of 6-methyl-5-hepten-2-one vapor on peel browning of ‘Delicious’ and ‘Granny Smith’ apples: open vs. closed system

Abstract An open and a closed system were used to evaluate the effects of 6-methyl-5-hepten-2-one (MHO) vapor on peel browning or scald development of ‘Delicious’ and ‘Granny Smith’ (scald susceptible) or ‘Fuji’ and ‘Gala’ (scald resistant) apples. In the open system, fruit were placed on the top of a beaker containing MHO and held in a ventilation hood with airflow of 0.56 m s−1 at 20 °C for 4 days. In the closed system, an open beaker containing MHO, together with 30 apples, was sealed in a 30-l jar, which was opened for 1 h every 2 days for 7 days at 20 °C. Differing scald susceptibilities for ‘Delicious’ and ‘Granny Smith’ were created using fruit at harvest (least susceptible), fruit stored in regular air (RA) for 4 months or controlled atmosphere (CA) for 6 months 0 °C (most susceptible), or fruit treated with DPA at harvest and then stored in RA for 4 months or CA for 6 months at 0 °C (less susceptible). At harvest, MHO induced peel browning over 100% of the treated area of the four cultivars in the open system but induced no browning on fruit in the closed system. Fruit treated similarly with acetone or ethanol showed peel browning in the open system but not in the closed system. Scald developed after 4 months RA storage in ‘Delicious’ and ‘Granny Smith’ and after 6 months CA storage in ‘Granny Smith’. Scald increased in these fruit after 7 days at 20 °C. DPA treatment inhibited scald both during storage and during the poststorage period at 20 °C. In the open system, MHO treatment increased MHO concentrations in fruit peel by 100-fold and induced uniform peel browning in the treated area within 24 h in both cultivars regardless of storage condition or DPA treatment. The severity of the symptom increased with time. In the closed system, although MHO treatment increased MHO concentration in fruit peel by 3–10 fold compared with untreated controls, it did not change scald development regardless of cultivar, storage condition, or DPA treatment.

Determination of rare earth elements in environmental matrices by sector-field inductively coupled plasma mass spectrometry.

In the framework of an international certification campaign, sector-field inductively coupled plasma mass spectrometry (sector-field ICP-MS) was used for the accurate determination of the rare earth elements in five candidate reference materials: aquatic plant, calcareous soil, mussel tissue, river sediment, and tuna muscle. All samples were taken into solution by use of microwave-assisted or mixed microwave-assisted / open beaker acid digestion. Subsequently, the samples were appropriately diluted and subjected to ICP-MS analysis. Except for Sc, all the elements involved were determined at low mass resolution (R = 300). For Sc, application of a higher resolution setting (R = 3,000) was required to separate the analyte signal from those of several molecular ions which gave rise to spectral overlap at low mass resolution. Some of the heavier REE can also suffer from spectral overlap attributed to the occurrence of oxide ions (MO+) of the lighter REE and Ba. This spectral overlap could be successfully overcome by mathematical correction. Matrix effects were overcome by use of two carefully selected internal standards, such that external calibration could be used. On each occasion, a geological reference material was analyzed as a quality-control sample and the reliability of all results obtained was additionally checked by means of chondrite normalization. For tuna muscle the content of all REE was below the limit of detection. For calcareous soil and river sediment, low to sub microg g(-1) values were observed, whereas the REE content of aquatic plant and mussel tissue was considerably lower (low to sub ng g(-1)). Overall, the results obtained were in excellent agreement with the average values, calculated on the basis of all "accepted" values, obtained in different laboratories using different techniques.

Separation of cobalt and nickel by non-equilibrium solvent extraction

The separation of cobalt and nickel in the ammoniacal sulfate solution by non-equilibrium solvent extraction with a phosphate (P303) as extractant was studied. In the experiment, the effects of equilibrium pH value in aqueous phase, contact time of the two phases, the air-blowing time for feed liquor in the open beaker on percentage extraction of cobalt and nickel and percentage reextraction of nickel from the loaded organic phase with dilute H2SO4. etc were studied. The results showed that: Co(II) can be oxidized to Co(III)-ammino-complex by adding (NH4)2S2O8 or blowing air to the aqueous phase, and Co(III)-ammino-complex is a kind of kinetically inert complex. Its extractive speed is very slow, while the nickel’s is much faster than that of cobalt. By controlling the contact time of the two phases, nickel can be separated from cobalt by non-equilibrium solvent extraction. Then nickel was reextracted from the loaded organic phase with dilute H2SO4.