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1
Mondino, Federico, Amelia Piscitello, Carlo Bianco, Andrea Gallo, Alessandra de Folly D’Auris, Tiziana Tosco, Marco Tagliabue, and Rajandrea Sethi. "Injection of Zerovalent Iron Gels for Aquifer Nanoremediation: Lab Experiments and Modeling." Water 12, no. 3 (March 15, 2020): 826. http://dx.doi.org/10.3390/w12030826.
Повний текст джерелаАнотація:
One of the main technical problems faced during field-scale injections of iron microparticles (mZVI) for groundwater nanoremediation is related to their poor colloidal stability and mobility in porous media. In this study, a shear-thinning gel, composed of a mixture of two environmentally friendly biopolymers, i.e., guar gum and xanthan gum, was employed to overcome these limitations. The slurry rheology and particle mobility were characterized by column transport tests. Then, a radial transport experiment was performed to mimic the particle delivery in more realistic conditions. The gel, even at a low polymeric content (1.75 g/L), proved effective in enhancing the mobility of high concentrated mZVI suspensions (20 g/L) in field-like conditions. The high radius of influence (73 cm) and homogeneous iron distribution were achieved by maintaining a low injection overpressure (<0.4 bar). Based only on the information derived from column tests, the MNMs 2018 software (Micro- and Nanoparticle transport, filtration, and clogging Model-Suite) was able to predict the particle distribution and pressure build-up measured in the radial domain. Experimental and simulated results showed good agreement, thus proving that a simplified experimental-modeling procedure based on 1D column tests could be used to effectively upscale the slurry behavior to more representative scales, e.g., radial domains.
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Song, J. H., and J. R. G. Evans. "Flocculation after injection molding in ceramic suspensions." Journal of Materials Research 9, no. 9 (September 1994): 2386–97. http://dx.doi.org/10.1557/jmr.1994.2386.
Повний текст джерелаАнотація:
The flocculation of an unstabilized suspension of fine ceramic particles is advanced as the explanation for the formation of cracks in a “liquid” suspension. The development of cracks was observed several minutes after reheating wax-based ceramic moldings above the melting point of the wax and was accompanied by phase separation of the wax from the molding. Calculations of the acceleration of particles under London dispersion forces in a viscous fluid show the “time to impact” as a function of initial separation distance, fluid viscosity, and particle size. This is compared with the intercollision time calculated from classical flocculation theory, and it is shown that for crowded suspensions initial interparticle distances are such that the London force field cannot be neglected. Methods of preventing the flocculation are described.
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RANKIN, P. J., Y. M. SHKEL, D. J. KLINGENBERG, and J. L. SHOHET. "PROBING ASPECTS OF NONLINEAR CONDUCTION IN ELECTRORHEOLOGICAL SUSPENSIONS." International Journal of Modern Physics B 15, no. 06n07 (March 20, 2001): 965–72. http://dx.doi.org/10.1142/s0217979201005489.
Повний текст джерелаАнотація:
Particle and electrode surfaces were altered to examine the effects on the electrorheological response of barium titanate/silicone oil suspensions. Unmodified suspensions exhibited nonlinear conduction. The dynamic yield stresses scaled as En, where n<2 at all electric field frequencies, and the current had substantial harmonic content, a hallmark of nonlinear conduction. Modifying the particle surfaces did not affect these nonlinear responses. Casting polymers on the electrode surfaces changed the responses. With polymer coatings, the dynamic yield stresses scaled as En, where n≥2 at some frequencies and increased with coating thickness. With coated electrodes, the current harmonic contents were significantly decreased. These results suggest that nonlinear conduction in ER suspensions is associated with charge injection at the electrode/liquid interface.
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Tseng, Huan-Chang, Rong-Yeu Chang, and Chia-Hsiang Hsu. "Predictions of fiber concentration in injection molding simulation of fiber-reinforced composites." Journal of Thermoplastic Composite Materials 31, no. 11 (November 2, 2017): 1529–44. http://dx.doi.org/10.1177/0892705717738302.
Повний текст джерелаАнотація:
The microstructures of injection-molded short fiber composites, involving fiber orientation and fiber concentration, strikingly influence flow behaviors and mechanical properties. Through the use of certain commercial software, reported numerical predictions of fiber orientation for the shell–core structure have been obtained to date. However, no work has been done on fiber concentration prediction available in processing simulations. In the theoretical field of suspension rheology, the suspension balance (SB) model has proven successful in capturing particle migration behavior under the simple Couette shear flow of “spherical” particle suspension, hence the attempt to verify the SB model applied in the “like-rod” suspensions. To predict flow-induced variations of fiber concentration, the SB model is implemented in 3-D-injection molding simulation with more general flows. It is remarkable for the shell–core structure is explored to reflect the relationship between fiber orientation and fiber concentration.
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Alert, Ricard, Jaume Casademunt, and Jean-François Joanny. "Active Turbulence." Annual Review of Condensed Matter Physics 13, no. 1 (March 10, 2022): 143–70. http://dx.doi.org/10.1146/annurev-conmatphys-082321-035957.
Повний текст джерелаАнотація:
Active fluids exhibit spontaneous flows with complex spatiotemporal structure, which have been observed in bacterial suspensions, sperm cells, cytoskeletal suspensions, self-propelled colloids, and cell tissues. Despite occurring in the absence of inertia, chaotic active flows are reminiscent of inertial turbulence, and hence they are known as active turbulence. Here, we survey the field, providing a unified perspective over different classes of active turbulence. To this end, we divide our review into sections for systems with either polar or nematic order, and with or without momentum conservation (wet or dry). Comparing to inertial turbulence, we highlight the emergence of power-law scaling with either universal or nonuniversal exponents. We also contrast scenarios for the transition from steady to chaotic flows, and we discuss the absence of energy cascades. We link this feature to both the existence of intrinsic length scales and the self-organized nature of energy injection in active turbulence, which are fundamental differences from inertial turbulence. We close by outlining the emerging picture, remaining challenges, and future directions.
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Mikhailov, А., and V. Ovseychuk. "Analysis of the results of complex processing of technological wells to restore their serviceability." TRANSBAIKAL STATE UNIVERSITY JOURNAL 28, no. 6 (2022): 15–25. http://dx.doi.org/10.21209/2227-9245-2022-28-6-15-25.
Повний текст джерелаАнотація:
Laboratory tests to establish the influence of the material and particle size distribution composition of hydrogenous ores on the intensity of sedimentation of colmatants during in-situ leaching have established that the main reason for loss of productivity of technological wells during in-situ leaching of hydrogenous ores of the Khiagda ore field deposits is colmatation of their near-filter zone. The greatest influence is exerted by mechanical and chemical colmatation, in the process of which fine mechanical suspensions accumulate in the near-filter zone and products of chemical reactions occurring during leaching [4; 9–12]. It has been determined that the most effective way to eliminate mechanical bridging is pneumatic-pulse processing of the filter zone of technological wells, and the use of processing wells with hydrochloric acid and ammonium bischofite allows to remove most of the chemical bridging agents deposited on the structural elements of the well reinforcement [2, 3]. The conducted research makes it possible to improve the regulation of repair and restoration works when treating technological wells in the process of carrying out production works at the hydrogenous deposits of the Khiagda ore field. The results of applying technical solutions to restore the serviceability of injection and injection wells are given in this article
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GAREEV, B. M., A. M. ABDRAKHMANOV, and G. L. SHARIPOV. "SONOLUMINESCENCE SPECTROSCOPY OF COLLOIDAL SUSPENSIONS: MOLECULAR, IONIC AND ATOMIC LUMINESCENCE DURING SONOCHEMICAL DECOMPOSITION OF SILICON DIOXIDE NANOPARTICLES CONTAINING RUTHENIUM AND COPPER COMPOUNDS." Izvestia Ufimskogo Nauchnogo Tsentra RAN, no. 4 (December 13, 2021): 16–21. http://dx.doi.org/10.31040/2222-8349-2021-0-4-16-21.
Повний текст джерелаАнотація:
The article is devoted to an example of the sonoluminescence spectroscopy use, which was previously known as a method for analyzing substances from the characteristic spectra of their sonoluminescence only in true solutions, for carrying out a similar analysis of substances contained in insoluble nanoparticles in colloidal suspensions. The solutions sonolysis, that is, their irradiation with ultrasound, is accompanied by the formation of cavitation bubbles that vibrate radially at the frequency of the ultrasonic field. Volatile components of the solution enter the bubbles, evaporating from the liquid-gas interface; nonvolatile components can penetrate into the bubble as a result of the injection of solution nanodroplets into the gas phase, which occurs during intense bubble movements accompanied by their deformation. In a nonequilibrium plasma periodically forming in cavitation bubbles, destruction occurs, as well as collisional excitation of these components, followed by luminescence. It has been shown that this mechanism of sonoluminescence also operates in colloidal suspensions, where substances are present in the form of nanoparticles with sizes less than 50 nm. Such nanoparticles penetrate into moving cavitation bubbles, without destroying them, as part of nanodroplets, and then undergo decomposition in bubble plasma with the excited particles generation as emitters of characteristic sonoluminescence. In this work, we synthesized colloidal suspensions in dodecane of porous SiO2 nanoparticles containing adsorbed Ru(bpy)3Cl2 and CuSO4 salts. During moving single-bubble sonolysis for these suspensions, characteristic emission spectra of Ru and Cu atoms, SiO molecules, and Ru(bpy)3 ions suitable for sonoluminescence spectroscopic analysis were recorded. By comparing the experimental and calculated (at different temperatures) luminescence spectra of Ru atoms, we estimated the electron temperature attained upon acoustic compression of single bubble in colloidal suspension in dodecane: Te = 7000 K.
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Zhang, Xi, Lifeng Yang, Dingwei Weng, Zhen Wang, and Robert G. Jeffrey. "Numerical Study on Proppant Transport in Hydraulic Fractures Using a Pseudo-3D Model for Multilayered Reservoirs." SPE Journal 27, no. 01 (October 26, 2021): 77–92. http://dx.doi.org/10.2118/206756-pa.
Повний текст джерелаАнотація:
Summary In this paper, we incorporated a kinematic proppant transport model for spherical suspensions in hydraulic fractures developed by Dontsov and Peirce (2014) in a pseudo-3D hydraulic-fracture simulator for multilayered rocks to capture a different proppant transport speed than fluid flow and abridged fracture channel by highly concentrated suspensions. For pressure-driven proppant transport, the bridges made of compact proppant particles can lead to both proppant distribution discontinuity and increased fracture aperture and height because of the higher pressure. The model is applied to growth of a fracture from a vertical well, which can contain thin-bedded intervals and more than one opened hydraulic-fracture interval, because the fracture plane extends in height through layers with contrasts in stress and material properties. Three numerical examples demonstrate that a loss of vertical connectivity can occur among multiple fracture sections, and proppant particles are transported along the more compliant layers. The proppant migration within a narrow fracture in a thin soft rock layer can result in bridging and formation of a proppant plug that strongly limits fluid speed. This generates an increase of injection pressure associated with fracture screenout, and these screenout events can emerge at different places along the fracture. Next, because of the lack of pretreatment geomechanical data, the values of layer stress and leakoff coefficient are adjusted for a field case so that the varying bottomhole pressure and fracture length are in line with the field measurements. This paper provides a useful illustration for hydraulic-fracturing treatments with proppant transport affected by and interacting with reservoir lithological complexities.
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Li, Jinlong, Xiangru Xu, Yanling Ma, Qixin Sun, Chaojie Xie, and Jun Ma. "An Improved Inoculation Method to Detect Wheat and Barley Genotypes for Resistance to Fusarium Crown Rot." Plant Disease 106, no. 4 (April 1, 2022): 1122–27. http://dx.doi.org/10.1094/pdis-09-21-1871-re.
Повний текст джерелаАнотація:
Fusarium crown rot (FCR), caused by Fusarium species, is a serious soilborne fungal disease in many wheat growing regions in the world. A reliable FCR assessment method is essential for germplasm screening and host resistance studies. Here, we report a new assay in which we inoculated wheat seedlings grown in a glasshouse for FCR by injecting spore suspensions into the seedling stems. The effects of inoculum concentration and injection time points on disease severity were investigated. Of different treatments, the injection of 107 macroconidia/ml suspension at one leaf and one heart stage gave best results. A collection of 92 emmer-derived hexaploid bread wheats, 43 barley germplasms, and four wheat genotypes with known resistance levels to FCR was used to validate this new method. Repeatability of the two trials in the validation experiments was high (r = 0.97, P < 0.01). Two emmer-derived hexaploid bread wheat and three Chinese barley germplasms showed consistent resistance to FCR in multiple rounds of selection. The short timeframe of this assay for phenotypic screening makes it a valuable tool to eliminate germplasms with undesirable susceptibility to FCR at seedling stage before costly field assays.
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Gullapalli, Irene Lee, Jae H. Bae, Keith Hejl, and Aimee Edwards. "Laboratory Design and Field Implementation of Microbial Profile Modification Process." SPE Reservoir Evaluation & Engineering 3, no. 01 (February 1, 2000): 42–49. http://dx.doi.org/10.2118/60910-pa.
Повний текст джерелаАнотація:
Summary A microbial profile modification (MPM) process consisting of sequential injection of spores and nutrient was designed and tested for the first time in a carbonate reservoir. An 80-acre, inverted five-spot pattern located in Eunice Monument South Unit in Lea County, New Mexico, was chosen for the field trial. Injection profiles taken before and after the microbial treatment showed that the thief zones were plugged by the biofilm resulting in fluid diversion. Injection profiles also indicated that the biofilm which formed in the reservoir remained stable for more than 8 months. The results of the field trial proved the viability of the MPM technology. Introduction Field History and Geology. The Eunice Monument field is located on the northwestern edge of the Central Basin Platform in southeastern Lea County, New Mexico, approximately 15 miles southwest of the city of Hobbs. The field was discovered on March 21, 1929 with the majority of field development occurring from 1934 through 1937. The well development in the Eunice Monument South Unit (EMSU) was on 40-acre spacing. In May 1937, primary oil production peaked. The field was produced under primary means until unitization of the field occurred in February 1985. Oil was produced primarily from dolomites of the Permian (Guadalupian) -aged Grayburg Formation. A minor amount of production was also from the overlying lower Queen (Penrose) Formation. Underlying the Grayburg is the San Andres Formation, a waterdrive reservoir. The Grayburg is at an average depth of about 3,700 ft and averages 250 ft thick with a reservoir temperature of 90°F. It is subdivided into six zones based on relatively thin, generally impermeable sandstone. Porosity ranges up to approximately 20% with a fieldwide average of 9.4%. The permeability range is approximately 0.01 to 75 md with an average of 13 md. The reservoir is very heterogeneous with the DP coefficient of about 0.85. Waterflood pattern development of the unit was 80-acre five-spot, and the initial injection was started in November 1986 with full-scale injection underway by June 1988. The early water injection rate was limited to between 500 and 700 B/D per injector, and later the rates were increased from 500 to 2,500 B/D per well. The original oil in these formations was estimated to be 671.5 MMSTBO, and the cumulative recovery to date has been approximately 127 MMSTBO. The crude oil is light with a gravity of 32°APl, and the reservoir brine contains substantial amounts of calcium and magnesiums ions. The brine compositions are listed in Table 1. Microbial Profile Modification Process. In our previous papers,1,2 we presented the basic concept and some data on a microbial profile modification (MPM) process. The microbe used for this process is Salton-1, a gram-positive, rod-shaped bacterium with a width of about 0.2 to 0.3 ?m and a length of 0.5 to 1.0 ?m. It closely resembles the species Bacillus licheniformis,3 and is a facultative anaerobic mesophile. More details of this process are given elsewhere.1 In this paper, the laboratory design and implementation of the MPM process in the EMSU field are presented. Experiment All tube and core tests were conducted at 90°F. To simulate reservoir environment, test tubes containing inoculum, were anaerobically incubated. For core tests, fired Berea cores with dimensions of 2.54 cm diam×30 were used. In some tests, reservoir plugs of 2.5 cm diam×5 to 6 cm length were used. The brine permeability of all Berea cores was about 1,000 md to mimic the thief zones. The specific values are noted in the figures. All nutrient media and spore suspensions prepared for the core and tube tests were made in injection water unless otherwise stated. We used a backpressure of 1,500 psi in the core tests to remove any spurious effect of the gas produced by the microbial activity on permeability reduction. The Berea cores had two pressure taps, equally spaced along the core. The Hassler type of core holder was used for the reservoir plugs. Generally, a 1-PV of 107 (colony forming unit per mL) of spore suspension was followed by an equal amount of nutrient solution, and the core containing inoculum was incubated or shut in for a specified period, followed by post-brineflush. The injection rate was 10 mL/h. Thereafter, some cores containing biofilm were further incubated for stability test. Any deviation from these procedures has been specified as appropriate. The fermented medium was microscopically examined to check the viability of the microbes and also the stage of their life cycle. In addition, viable counts or enumeration were done on agar plates. The stability of biofilm was assessed by hand shaking of the tube, and the biofilm was termed stable if it did not break upon shaking. Field water analysis was performed with an ion chromatography unit (IC). Eluants were made with de-gassed DI water and filtered through a 0.22 ?m filter. Helium gas was initially bubbled through the eluant and the eluant was kept under the helium blanket throughout the experiment. The injection and the produced water samples were passed through a cation exchange (SCX) column to remove cations prior to the chromatographic runs. Also, the guard and analytical columns were preconditioned prior to the sample runs to establish a stable baseline, and were tested with known samples for concentration and retention time. For anion analysis, a conductivity detector with AS4A-SC analytical and guard columns, as well as an anion membrane suppressor, was used. The eluant was a mixture of 1.8 mM of Na2CO3 and 1.7 mM of NaHCO3 . The membrane suppressor solution was 50 mN of H2SO4. Inductively coupled plasma (ICP) spectroscopy was used for the cation analysis.
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Pak, Tannaz, Luiz Fernando de Lima Luz, Tiziana Tosco, Gabriel Schubert Ruiz Costa, Paola Rodrigues Rangel Rosa, and Nathaly Lopes Archilha. "Pore-scale investigation of the use of reactive nanoparticles for in situ remediation of contaminated groundwater source." Proceedings of the National Academy of Sciences 117, no. 24 (June 2, 2020): 13366–73. http://dx.doi.org/10.1073/pnas.1918683117.
Повний текст джерелаАнотація:
Nanoscale zero-valent iron (nZVI) particles have excellent capacity for in situ remediation of groundwater resources contaminated by a range of organic and inorganic contaminants. Chlorinated solvents are by far the most treated compounds. Studies at column, pilot, and field scales have reported successful decrease in contaminant concentration upon injection of nZVI suspensions in the contaminated zones. However, the field application is far from optimized, particularly for treatments at—or close to—the source, in the presence of residual nonaqueous liquid (NAPL). The knowledge gaps surrounding the processes that occur within the pores of the sediments hosting those contaminants at microscale limit our ability to design nanoremediation processes that are optimized at larger scales. This contribution provides a pore-scale picture of the nanoremediation process. Our results reveal how the distribution of the trapped contaminant evolves as a result of contaminant degradation and generation of gaseous products. We have used state-of-the-art four-dimensional (4D) imaging (time-resolved three-dimensional [3D]) experiments to understand the details of this degradation reaction at the micrometer scale. This contribution shows that the gas released (from the reduction reaction) remobilizes the trapped contaminant by overcoming the capillary forces. Our results show that the secondary sources of NAPL contaminations can be effectively treated by nZVI, not only by in situ degradation, but also through pore-scale remobilization (induced by the evolved gas phase). The produced gas reduces the water relative permeability to less than 1% and, therefore, significantly limits the extent of plume migration in the short term.
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Yang, Ping, and Yong Cheng. "Determination of Trace Mercury in the Titanium Dioxide by Ultrasonic Oscillation - The Suspension Solid Sampling GF-AAS." Advanced Materials Research 779-780 (September 2013): 12–16. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.12.
Повний текст джерелаАнотація:
Established the analytical method by using ultrasonic vibration - suspension of solid sampling graphite furnace atomic absorption spectrometry (GF-AAS) to test trace mercury in the titanium dioxide, by choosing a suitable concentration of agar solution as dispersing agent, and taking the ultrasonic oscillation technique to prepare uniform and stable titanium dioxide suspended solid solution, and finally using the solid injection sampling GF-AAS method to test trace elements of mercury.. Through the application of solid injection technique, the problem that the titanium dioxide is extremely difficult to digest and mercury volatile loss are solved and the matrix effect of the high titanium is eliminated by standard addition method as well. The paper has tested the conditions of preparation of solid suspension such as agar dispersing agent concentration, dosage, and ultrasonic vibration parameters. and titanium dioxide solid suspensions obtained by the method have the characters of uniformity, stability, mobility features, and preserve a long time. Graphite furnace testing procedures are also optimized: drying temperature 85 °C, time 30 s, by lowering the drying temperature and measures to extend the time to solve the contradiction of water evaporation and mercury volatilization; cancel the ashing step directly into the atomization stage in order to avoid mercury loss after drying. Finally, set atomic temperature 1 000 °C, for 5 s and close the purged argon flow of the internal graphite tube to ensure mercury exists as different forms such as free, particle adsorption or parcels can be effective tested. The detection limit is from 0.000 to 005% and recovery rate is from 93% to 109%, RSD <3.1%. The results of the test is correspond with that of Microwave Digestion and Inductively Coupled Plasma Mass Spectrometry method. The methods can meet the requirement of testing toxic trace elements mercury in high-grade titanium dioxide which used in medical, food, ceramics and other field.
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Berlitz, D. L., M. Giovenardi, J. F. Charles, and L. M. Fiúza. "Toxicity intraperitoneal and intragastric route of Bacillus thuringiensis and Melia azedarach in mice." Arquivos do Instituto Biológico 79, no. 4 (December 2012): 511–17. http://dx.doi.org/10.1590/s1808-16572012000400007.
Повний текст джерелаАнотація:
The aim of this investigation was the assessment of toxicity of two new isolates of Bacillus thuringiensis, and the aqueous extract of Melia azedarach through in vivo assays in CF1 mice. Bt 1958-2, Bt 2014-2 and the BTh Thuricide 63 standard isolates were grown in liquid usual glicosed medium, and Cry proteins were purified by centrifugation on a sucrose gradient. The supernatant was autoclaved at 121º C, 15min. to maintain the exotoxins. Dehydrated leaves of M. azedarach were used to prepare a 10% aqueous extract. Mice were treated either orally or intraperitoneally with a whole bacterial suspension (1.10(10) UFC/mL), a culture supernatant or purified crystal protein (50 µg/mL), and with the plant extract (50 µg/mL). The stomachs of the mice were collected and observed in stereomicroscopy, and the stomach contents were analyzed in 10% SDS-PAGE. Results showed that none of the oral treatments were toxic to mice, but intraperitoneal bacterial suspensions were lethal to the animals 6 - 24 hours after injection. In conclusion, the Cry proteins of the new B. thuringiensis isolates must be evaluated for their use as tools in the biotechnology field, since they do not show toxicity against mammals, intragastrically or peritoneally, just like the M. azedarach aqueous extract (10%), with those being indicated for the biological control of pest insects.
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Zadnik, Patricia L., Camilo A. Molina, Rachel Sarabia-Estrada, Mari L. Groves, Michele Wabler, Jana Mihalic, Edward F. McCarthy, Ziya L. Gokaslan, Robert Ivkov, and Daniel Sciubba. "Characterization of intratumor magnetic nanoparticle distribution and heating in a rat model of metastatic spine disease." Journal of Neurosurgery: Spine 20, no. 6 (June 2014): 740–50. http://dx.doi.org/10.3171/2014.2.spine13142.
Повний текст джерелаАнотація:
Object The goal of this study was to optimize local delivery of magnetic nanoparticles in a rat model of metastatic breast cancer in the spine for tumor hyperthermia while minimizing systemic exposure. Methods A syngeneic mammary adenocarcinoma was implanted into the L-6 vertebral body of 69 female Fischer rats. Suspensions of 100-nm starch-coated iron oxide magnetic nanoparticles (micromod Partikeltechnologie GmbH) were injected into tumors 9 or 13 days after implantation. For nanoparticle distribution studies, tissues were harvested from a cohort of 36 rats, and inductively coupled plasma mass spectrometry and histopathological studies with Prussian blue staining were used to analyze the samples. Intratumor heating was tested in 4 anesthetized animals with a 20-minute exposure to an alternating magnetic field (AMF) at a frequency of 150 kHz and an amplitude of 48 kA/m or 63.3 kA/m. Intratumor and rectal temperatures were measured, and functional assessments of AMF-exposed animals and histopathological studies of heated tumor samples were examined. Rectal temperatures alone were tested in a cohort of 29 rats during AMF exposure with or without nanoparticle administration. Animal studies were completed in accordance with the protocols of the University Animal Care and Use Committee. Results Nanoparticles remained within the tumor mass within 3 hours of injection and migrated into the bone at 6, 12, and 24 hours. Subarachnoid accumulation of nanoparticles was noted at 48 hours. No evidence of lymphoreticular nanoparticle exposure was found on histological investigation or via inductively coupled plasma mass spectrometry. The mean intratumor temperatures were 43.2°C and 40.6°C on exposure to 63.3 kA/m and 48 kA/m, respectively, with histological evidence of necrosis. All animals were ambulatory at 24 hours after treatment with no evidence of neurological dysfunction. Conclusions Locally delivered magnetic nanoparticles activated by an AMF can generate hyperthermia in spinal tumors without accumulating in the lymphoreticular system and without damaging the spinal cord, thereby limiting neurological dysfunction and minimizing systemic exposure. Magnetic nanoparticle hyperthermia may be a viable option for palliative therapy of spinal tumors.
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Cantore, P. Lo, and N. S. Iacobellis. "First Report of Head Rot of Brassica oleracea convar. botrytis var. italica Caused by Pseudomonas fluorescens in Southern Italy." Plant Disease 91, no. 5 (May 2007): 638. http://dx.doi.org/10.1094/pdis-91-5-0638a.
Повний текст джерелаАнотація:
During the winter of 2004, symptoms were observed in commercial cauliflower (Brassica oleracea L. convar. botrytis (L.) Alef. var. italica) fields of “romanesco” type (cv. Navona) in Apulia, southern Italy. These symptoms were noted on inflorescences that were almost ready for harvest, and a bacterial etiology was suspected. In particular, the corymbs showed water-soaked and brown discolored areas which then rotted. The above alterations involved the whole inflorescences, or in some cases, only a few florets. Longitudinal sections of the symptomatic inflorescences or the single floret showed brown discoloration and rotting of the internal tissues. The disease caused severe crop losses (approximately 100% either in the field or after harvest). Bacteria were isolated from water-soaked and soft-rotted cauliflower heads on King's medium B (KB). The strains were purified on nutrient agar and assayed for pathogenicity on subcorymbs from freshly harvested cauliflower heads. Bacterial suspensions containing approximately 108 CFU/ml were then sprayed on the surface of subcorymbs (3 subcorymbs per strain). Furthermore, in other pathogenicity assays, the florets were dipped in 108 CFU/ml bacterial suspensions or small aliquots of inoculum were injected into the peduncle of subcorymbs with a sterile syringe. Cauliflower heads treated with sterile distilled water were used as controls. After inoculation, the subcorymbs were maintained at 25°C and approximately 100% relative humidity for 48 h. All bacterial strains either applied to cauliflower subcorymbs by spray inoculation or dipping reproduced the disease symptoms. Intensity of symptoms varied with the inoculation method. Injection of bacteria caused water soaking and soft rot of cauliflower internal tissues. No symptoms were observed in negative control subcorymbs inoculated with sterile water. All bacterial strains were gram negative and fluorescent on KB. Isolates (17 of 18) showed the LOPAT characters of group Vb (++−+−) fluorescent pseudomonads, and only strain USB1237 showed characters of group IVb (−+++−) (3). The pectolytic activity of the latter strain was confirmed by the pectinase plate assay (4). The identity of representative strains was confirmed by the nutritional profile obtained with the Biolog Identification System (MicroLogTM System Release 4.2; Biolog, Inc., Hayward, CA). Strains USB1224, USB1226, USB1228, USB1231, USB1235, USB1236, USB1238, and USB1239 were identified as Pseudomonas fluorescens with similarity indices of 0.86, 0.52, 0.73, 0.81, 0.73, 0.74, 0.69, and 0.85, respectively. The pectolytic strain USB1237 was identified as a Pseudomonas spp. that is closely related to P. putida (similarity index = 0.45). In conclusion, the above results indicate that P. fluorescens is responsible for head rot of cauliflower. A similar disease has been previously reported on broccoli in different areas (1,2), but to our knowledge, this is the first report of head rot of cauliflower caused by P. fluorescens. References: (1) C. H. Canaday et al. Phytopathology 77:1712, 1987. (2) P. D. Hildebrand. Can. J. Plant Pathol. 8:350, 1986. (3) R. A. Lelliott and D. E. Stead. Methods for the diagnosis of bacterial diseases of plants. In: Methods in Plant Pathology. Vol. 2, T. F. Preece, ed. Blackwell Scientific Publications, Oxford, UK, 1987. (4) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. The American Phytopathological Society, St. Paul, MN, 2001.
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Alippi, A. M., S. Wolcan, and E. Dal Bó. "First Report of Bacterial Leaf Spot of Basil Caused by Pseudomonas viridiflava in Argentina." Plant Disease 83, no. 9 (September 1999): 876. http://dx.doi.org/10.1094/pdis.1999.83.9.876b.
Повний текст джерелаАнотація:
In June 1998, during a cool, humid period, typical bacterial spot symptoms were observed on basil plantlets (Ocimun basilicum L. ‘Royal Louis’ and ‘Zaes’) in a commercial greenhouse in La Plata, Argentina. Affected plants had dark brown to black lesions on cotyledons. Spots on leaves were first water soaked, then became necrotic and progressed inward from the margins. Disease incidence approached 30%. Symptoms were similar to those reported by Little et al. (2) on basil affected by Pseudomonas viridiflava. No pathogenic fungi or viruses were associated with symptomatic plants. Bacterial streaming was observed from lesion margins. Bacteria consistently isolated from leaf lesions formed cream-colored, glistening, convex colonies on sucrose peptone agar and a green fluorescent pigment on King's medium B. Bacterial growth produced a distinctive olive green pigment on glycerol agar medium and a pink pigment on T-5 medium (1). Four isolates selected for further study were aerobic, Gram-negative, non-spore-forming rods. In LOPAT (levan-oxidase-potato rot-arginine dihydrolase-tobacco hypersensitivity) tests, all induced a hypersensitive response in tobacco plants, caused soft rot of potato tubers, and were negative for levan, oxidase, and arginine dihydrolase. In addition, strains rotted onion slices and produced a reddish sunken lesion on bean pods. Acid was produced aerobically from D-glucose, mannitol, mesoinositol and sorbitol, but not from D-arabinose, L-rhamnose, melibiose, amygdalin, or sucrose. Bacteria used D-tartrate, pyruvate, and citrate, but not benzoate. The strains did not hydrolyze starch, exhibited an oxidative metabolism of glucose, and did not reduce nitrates to nitrites or accumulate poly-β-hydroxybutyrate inclusions. Negative reactions were obtained with indole, ornithine, and D-tryptophan. Isolates hydrolyzed gelatine, used Tween 80, were positive for catalase, and were unable to grow in the presence of 5% NaCl. Colonies developed at 4°C but not 37°C. Reactions were identical to those of reference strains ICMP 5776 and 12363, which were included in all tests for comparison. Pathogenicity was verified on 35-day-old basil plants by both spraying and infiltration inoculations with bacterial suspensions (108 and 105 cells per ml, respectively). Carborundum was included in the inoculum used for a set of plants inoculated by spraying. Controls were injected or sprayed (with and without Carborundum) with sterile, distilled water. In addition, bean (Phaseolus vulgaris cv. Nag12 INTA) and lettuce (Lactuca sativa cv. criolla), both reported as host plants, were inoculated by spraying with bacterial suspensions of 107 cells per ml plus Carborundum. After 48 h in a humid chamber, inoculated plants and controls were maintained at 23 ± 3°C. Symptoms on basil plants inoculated by injection or spraying with Carborundum were identical to those observed on basil in the field. Symptoms on bean and lettuce were similar to those described for P. viridiflava. The bacterium was reisolated from lesions of all species tested, fulfilling Koch's postulates. No lesions were observed on controls or on plants sprayed without Carborundum, suggesting that bacteria gain entry through wounds. The microorganism was identified by physiological tests and polymerase chain reaction as P. viridiflava. This is the first report of bacterial leaf spot of basil in Argentina. References: (1) R. Gitaitis et al. Plant Dis. 81:897, 1997. (2) E. L. Little et al. Plant Dis. 78:831, 1994.
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Gijón-Hernandez, A., D. Téliz-Ortiz, E. Cárdenas-Soriano, C. De León, A. Mora-Aguilera, D. Mejía-Sánchez, and R. De La Torre-Almaraz. "Leaf Stripe and Stem Rot Caused by Burkholderia gladioli, a New Disease of Maize in México." Plant Disease 92, no. 8 (August 2008): 1249. http://dx.doi.org/10.1094/pdis-92-8-1249c.
Повний текст джерелаАнотація:
A new maize disease appeared in the State of Veracruz, Mexico during 2003–2004. Initial symptoms in the leaves were small, white-yellow, watery spots, which coalesced into dry necrotic stripes that were 0.3 wide and 8 cm long. Reddening sometimes developed on these leaves. Stems developed a rot in the crown. The flag leaf showed a rot and necrosis at the base, rolled inward, and dried out. Necrosis developed at the base of the corn ears and their growth was halted. A bacterium characterized by white colonies was consistently isolated from lesions on casamino acid peptone and glucose (CPG), King's medium B, and nutrient agar media. Ten isolates were chosen for further characterization. Pathogenicity was confirmed in the greenhouse (25 to 30°C) on 45-day-old ASGROW 7573 maize plants by injection of bacterial suspensions (107 CFU/ml) at the base of the stem. Control maize seedlings were injected with phosphate buffer. Symptoms similar to those observed in the field were observed after 3 days on all inoculated plants but were not observed on control plants. Koch's postulates were fulfilled with reisolation of the inoculated strain from the inoculated tissues and confirmation was fulfilled by phenotypic characters and 16S rDNA sequences. The white colonies on CPG were slightly convex, shiny, circular with entire margins, gram negative, lacked arginine dihydrolase, did not produce fluorescent pigment on Pseudomonas F medium, and grew aerobically. The strains were able to utilize l-arabinose, d-mannitol, and cellobiose, but unable to utilize d-maltose and l-rhamnose. Gel hydrolysis was positive but starch hydrolysis was not positive. Colonies grew at 40°C. These characteristics are the same as those described previously for Burkholderia gladioli (3). The identity of these isolates was confirmed by 16S analysis with two universal primers, FD1 and RD1, for Eubacteria (2), which generate a 1,600-bp fragment. Two primers specific for the genus Burhkolderia, RHG-F and RHG-R that generate a 500-bp fragment (1) were also used for amplification. Comparison of sequences using Clustal W and Megaline, DNAstar software showed 100% similarity among strains isolated from the three counties (GenBank Accession Nos. EU161873 to EU161878) and 99% similarity of field isolates with B. gladioli in the GenBank database. To our knowledge, this is the first report of B. gladioli causing leaf stripe and stem rot of maize in Mexico. References: (1) J. J. Lipuma et al. J. Clin. Microbiol. 37:3167, 1999. (2) L. M. Rodrigues et al. Appl. Environ. Microbiol. 69:4249, 2003. 3) N. W. Shaad et al., eds. 3rd ed. Laboratory Guide for Identification of Plant Pathogenic Bacteria. The American Phytopathological Society, St. Paul, MN, 2001.
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Wierenga, Pieter K., Isabelle Lombaert, Willy Visser, Harm H. Kampinga, Gerald de Haan, and Rob P. Coppes. "Bone Marrow-Derived Stem Cells Reduce Radiation-Induced Damage to Salivary Glands." Blood 104, no. 11 (November 16, 2004): 1194. http://dx.doi.org/10.1182/blood.v104.11.1194.1194.
Повний текст джерелаАнотація:
Abstract The salivary glands are often included in the field of irradiation during radiotherapy of head and neck cancer. This can result in severe side-effects that reduces the quality of life of the patient and may even limit the treatment dose. Late damage to the salivary glands is mainly caused by exhaustion of the tissue specific stem cells. Post-irradiation replacement of salivary gland stem cells with donor stem cells may ameliorate radiation-induced complications. Bone marrow-derived stem cells (BMSC) have been shown to be multipotent and thereby able to engraft in many tissues after injury. In this study, we assessed the potential of BMSC to reduce irradiation-induced salivary gland damage. C57BL/6 mice were transplanted with bone marrow from eGFP transgenic animals. After two months the salivary glands of these chimeric mice were locally irradiated with 15 Gy. BMSC were mobilized 10, 30 and/or 60 days after irradiation by s.c. injection of rHu-PEG-G-CSF. Saliva secretion (μl/15 minutes) was measured up to 90 days after irradiation by pilocarpine induction. Hereafter, the glands were extirpated and examined for eGFP-expression. From every individual animal one parotid and one submandibular gland was used to prepare single cell suspensions in order to detect eGFP-positve cells by flow cytometry. The other parotid and submandibular glands were analyzed using confocal laser fluorescence scanning microscopy and light microscopy. G-CSF treatment yielded in an increase of saliva flow for all time points. The optimal time-point for mobilization, however, was 30 days after irradiation as is demonstrated by an improvement of salivary flow from 5 to 30% when compared to radiation alone. FACS analysis showed that up to 10% of the isolated cells were eGFP-positive. Microscopic analysis revealed a similar amount of positive cells and an improved morphology. Immuno-histochemistry using anti-SM-actin antibodies showed the close vicinity of actin and eGFP within the cells, demonstrating the occurence of BMSC derived myoepithelial cells in irradiated salivary glands. Furthermore, using cell-type specific antibodies, the meyoepethilial nature of the eGFP positive was revealed. In conclusion, the results show that BMSC home to severely damaged salivary glands after mobilization. Hence, BMSC mobilization could become a promising modality to ameliorate radiation-induced complications in salivary glands after radiotherapy.
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Baştaş, K. K., H. Hekimhan, S. Maden, and M. Tör. "First Report of Bacterial Stalk and Head Rot Disease Caused by Pectobacterium atrosepticum on Sunflower in Turkey." Plant Disease 93, no. 12 (December 2009): 1352. http://dx.doi.org/10.1094/pdis-93-12-1352b.
Повний текст джерелаАнотація:
Bacterial stalk and head rot on sunflower (Helianthus annuus) was investigated in Konya Province of Turkey in 2008. Disease incidence was estimated as 30%. Bacteria appeared as droplets and ooze and symptoms were dark and water-soaked necrotic areas on stems and heads. Twenty-four strains were isolated from lesions on stalks and heads of sunflower cv. TR3080 from a 25-ha field and identified as Pectobacterium atrosepticum (formerly Erwinia caratovora subsp. atroseptica) (2) on the basis of biochemical, physiological (3), and molecular tests (1). Bacteria were gram negative, rod shaped, fermentative, nonfluorescent on King's B medium; positive for gelatin liquefaction, CVP test, catalase, and pectolytic activity, growth on 5% NaCl, reducing substances from sucrose, acid-production from lactose and α-methyl glucoside; and negative for growth at 37°C, acid production from sorbitol and maltose, phosphatase activity, tests for egg yolk (lecithin), sensitivity to erythromycin, and pigmentation on yeast dextrose calcium carbonate agar medium. To distinguish between P. atrosepticum and P. carotovorum, particular attention was paid to the growth at 37°C, reducing substances from sucrose and the utilization of α-methyl glucoside. Mesophyll cells of tobacco plants (Nicotiana tobaccum cv. White Burley) were infiltrated with bacterial suspensions (108 cells/ml) or water (control). Brown, collapsed areas of tissues (hypersensitive response) were observed at the injection sites after incubation for 48 h at 28°C and 80% relative humidity. A P. atrosepticum-specific primer set, Y45/Y46 (3), was used in PCR reactions to generate a 439-bp DNA fragment. Reference strains, Eca17 from Aegean University, Department of Plant Protection (İzmir, Turkey) and NCPPB 1277 from Selcuk University, Department of Plant Protection, Konya, Turkey, were employed in all biochemical, physiological, and molecular tests as positive controls and similar results were obtained. Koch's postulates were carried out to establish a causal relationship between the bacteria and the disease. A bacterial suspension (108 CFU/ml) was injected into sunflower shoot tips and inoculated plants were incubated for 2 weeks at 28°C and 80% relative humidity. All bacterial strains obtained from the stalks and heads produced the rot symptoms and ooze following inoculation to the susceptible sunflower cv. TR 3080. No symptoms were observed on controls that were inoculated with sterile water. The bacteria were isolated from the lesions on stalks and heads and their identities confirmed by the biochemical, physiological, and molecular tests. All tests were performed three times on three plants per strain. To our knowledge, this is the first report of P. atrosepticum on sunflower in Turkey. Further research is needed to determine how far the disease is spread in Turkey since other provinces also grow sunflowers. References: (1) L. Gardan et al. Int. J. Syst. Evol. Microbiol. 53:381, 2003. (2) L. Hauben et al. Syst. Appl. Microbiol. 21:384, 1998. (3) A. Darrasse et al. Appl. Environ. Microbiol. 60:298, 1994.
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Tian, Y. L., Y. Q. Zhao, B. S. Hu, and F. Q. Liu. "First Report of Seedling Blight of Watermelon Caused by Acidovorax citrulli Transmitted from Rootstock of Pumpkin in China." Plant Disease 97, no. 3 (March 2013): 420. http://dx.doi.org/10.1094/pdis-10-12-0931-pdn.
Повний текст джерелаАнотація:
Bacterial fruit blotch (BFB) is a devastating disease caused by Acidovorax citrulli, which was first observed in the United States in 1988 (3). A. citrulli can cause severe infection on a wide range of cucurbits, including watermelon, cantaloupe, and pumpkin. Cotyledon symptoms are brown, angular, necrotic spots or large necrotic lesions. The disease is seedborne, so seeds usually serve as the primary inoculum source for BFB outbreaks (2). In July 2012, seedling blight was observed by local farmers from Anhui province in China on watermelon seedlings grafted to pumpkin rootstocks; lesions were morphologically similar to those caused by A. citrulli. Presence of A. citrulli was detected in symptomatic samples by using species-specific primers BX-L1/BX-S-R2 (1). The seed company claimed seeds of watermelon (cv. Changfeng) were certified free of bacterial fruit blotch, but pumpkin seeds (cv. Kangkuxianfeng-1) had not been tested for A. citrulli. For investigating the inoculum source, the remaining seeds of watermelon (cv. Changfeng) and pumpkin (cv. Kangkuxianfeng-1) for seedling production were collected from the farmer and processed for pathogen extraction as described by Walcott and Gitaitis (2). Two microliters of seed wash was used as template for PCR using primers BX-L1/BX-S-R2 (1). The experiment was conducted three times. A 279-bp DNA fragment was consistently amplified by PCR from seed wash of pumpkin seeds, but not from the seed wash of watermelon seeds. Three Acidovorax-like strains (A1, A2, and A3) were isolated from pumpkin seed wash using TWZ semi-selective medium (0.5% peptone, 0.025% CaCl2, 1% Tween-80, 50 mg/liter berberine, 50 mg/liter cycloheximide, 50 mg/liter 2,3,5-triphenyltetrazolium chloride). PCR was performed on the 16S rDNA gene from isolate strain A1, A2, and A3 (1,492 bp; GenBank Accession Nos. JX875533, JX875534, and JX875535) with primers rp1/fd2 (4), and PCR products were sequenced. Results of sequence analysis showed the sequences of strains A1, A2, and A3 were 99% identical to that of the type strain of A. citrulli AAC00-1 (NC_008752). Pathogencity was confirmed by injection of pumpkin cotyledons with bacterial suspensions of each isolate. Collected pumpkin seeds (n = 100 seeds) and watermelon seeds (n = 100 seeds) were planted in plastic pots containing sterilized field soil at room temperature to detect A. citrulli by a wet chamber growing out test. Eight days later, brown, angular, necrotic spots or wilt developed in pumpkin seedlings, but no symptoms were noted on the watermelon seedlings. To our knowledge, this is the first report of A. citrulli causing watermelon seedling blight transmitted from pumpkin seeds by grafting in China. References: (1) O. Bahar et al. Plant Pathol. 57:754, 2008. (2) R. R. Walcott and R. D. Gitaitis. Plant Dis. 84:470, 2000. (3) G. C. Wall et al. Phytopathology 78:1605, 1988. (4) W. G. Weisburg et al. J. Bacteriol. 173:697, 1991.
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Alippi, A. M., and A. C. López. "First Report of Leaf Spot Disease of Maize Caused by Pantoea ananatis in Argentina." Plant Disease 94, no. 4 (April 2010): 487. http://dx.doi.org/10.1094/pdis-94-4-0487a.
Повний текст джерелаАнотація:
From 2007 to 2008, an uncharacterized disease of maize (Zea mays L.) was observed in commercial fields of Laguna Blanca, Formosa, Argentina and from different fields of Santa Fe and Catamarca provinces of Argentina. Symptoms included light-colored necrotic streaks on leaves and tan or white irregular blotches that sometimes were surrounded by reddish purple-to-dark brown margins. Severity of symptoms varied greatly from one field to another. Abundant bacterial streaming was observed from lesions when examined at ×150. Gram-negative, facultatively anaerobic bacteria were consistently isolated from lesions. These formed light yellow-to-orange, glistening, convex colonies on yeast dextrose calcium carbonate agar incubated at 30°C. Ten isolates from ten different symptomatic plants were selected for further study. All isolates were motile, induced a hypersensitive response in tobacco plants, and were oxidase negative. Colonies developed at 37°C. Physiological and biochemical characterization with the API 20E test strips and database (bioMerieux, Buenos Aires, Argentina) showed that the strains belonged to the genus Pantoea. All strains were positive for β-galactosidase, utilized citrate and tartrate, and produced acid from d-glucose, d-mannitol, d-melibiose, l-arabinose, sucrose, meso-inositol, glycerol, d-sorbitol, and amygdalin. All were negative for arginine dihydrolase, lysine decarboxylase, ornithine decarboxylase, tryptophane deaminase, H2S production, urease, and reduction of nitrate to nitrite. Variable results were obtained for indole, gelatinase, and l-rhamnose. Their identity was confirmed by sequencing the 16S rRNA gene strain F327 (GenBank Accession No. GU068363). A BlastN search of GenBank revealed 99% nt identity with strains LMG 20103 (AF364847.1), LMG 20105 (AF364845.1), and LMG 2665 (FJ611815.1) of Pantoea ananatis. Pathogenicity was verified on Z. mays (EM 6079 HX, Dow Morgan) by injection-infiltration of bacterial suspensions at 105 CFU/ml. Controls were infiltrated with sterile distilled water. Plants were kept at 26 ± 3°C in a greenhouse. Symptoms were first detected 15 to 17 days after inoculation and then lesions expanded to resemble natural infections within 30 days. Bacteria were reisolated and the original and reisolated strains were compared by using repetitive sequence-based (rep)-PCR with ERIC primers (1) and fingerprints of the reisolated strains were identical to those of the original strains, thereby fulfilling Koch's postulates. No lesions were observed on controls. Known strains of P. stewartii from the United States (SW2, DC400, DC441, and DC283) were also tested for comparison. On the basis of sequencing data, pathogenicity, and physiological tests, the pathogen was identified as P. ananatis (4). To our knowledge, this is the first report of P. ananatis causing a disease of maize in Argentina, although a similar disease has been reported in Brazil (2) and Mexico (3). References: (1) F. J. Louws et al. Appl. Environ. Microbiol. 60:2286, 1994. (2) L. D. Paccola-Meirelles et al. J. Phytopathol. 149:275, 2001. (3) R. Pérez-y-Terrón et al. Australas. Plant Dis. Notes 4:96, 2009. (4) N. W. Schaad et al., eds. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2001.
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Muller, Katherine A., Lirong Zhong, and Christopher E. Bagwell. "Characterizing the Influence of Organic Polymers on the Specific Reactivity of Particulate Remedial Amendments." Frontiers in Environmental Science 9 (November 30, 2021). http://dx.doi.org/10.3389/fenvs.2021.703851.
Повний текст джерелаАнотація:
Commercially available particulate amendments demonstrate high reactivity for effective treatment of water soluble organic and inorganic contaminants in laboratory studies; however, transport of these particles is constrained in the subsurface. In many field applications, particulate amendments are mixed with organic polymers to enhance mobility for direct push applications or stabilize suspensions for high mass loadings. As such, the interactions between particulate amendments, organic polymers and contaminant species need to be systematically investigated to properly understand mechanistic processes that facilitate predictive performance metrics for specific applications in situ. In this study, batch experiments were conducted to quantify the effects of organic polymers (xanthan gum, guar gum, and sodium alginate), polymer concentration (800 and 4,000 mg/L), and aging (up to 28 days) on chromate treatment rate and capacity by two classes of amendments: reductants [granular zero-valent iron (gZVI), micron-ZVI (mZVI), sulfur modified iron (SMI)], and an adsorbent (bismuth sub-nitrate). When particulate amendments were suspended in polymer solutions, reductants retained between 84–100% of the amendment treatment capacity. Conversely, the adsorbent maintained 63–97% relative treatment capacity of the no-polymer control. Polymer solutions had a more pronounced impact on the rate of chromate removal; first order rates of chemical reduction decreased by as much as 70% and adsorption by up to 81% relative to the no-polymer controls. Polymer–amendment aging experiments also showed decreased Cr(VI) treatment capacity; reductants decreased by as much as 24% and adsorption decreased by as much as 44% after 28 days of incubation. While polymer suspensions are needed to aid the injection of particulate amendments into the subsurface, the results from this study indicate potential losses of treatment capacity and a decrease in the rate of remedial performance due to the physical and chemical interactions between polymer suspensions and reactive particulate amendments. Simple batch systems provide baseline characterization of tripartite interactions for the removal of Cr(VI). Additional work is needed to quantify the full impact of polymers on remedial outcomes under site relevant conditions at field scale.
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Ratha, Prakash Kumar, Satyaranjan Mishra, Ramshankar Tripathy, and Pradyumna Kumar Pattnaik. "Analytical approach on the free convection of Buongiorno model nanofluid over a shrinking surface." Proceedings of the Institution of Mechanical Engineers, Part N: Journal of Nanomaterials, Nanoengineering and Nanosystems, June 7, 2022, 239779142211039. http://dx.doi.org/10.1177/23977914221103982.
Повний текст джерелаАнотація:
This article focuses on the two-dimensional unsteady flow of an incompressible Casson nanofluid over a shrinking horizontal sheet under the influence of inclined magnetic field and in an advance dissipative heat due to Joule heating. The proposed Buongiorno model for the inclusion of Brownian and thermophoresis enriches the flow profiles. Casson model constituents a plastic fluid model that exhibits shear thinning characteristics and high shear viscosity. The proposed fluid model also approximates the rheological behavior of other liquids like physiological suspensions, cosmetics, syrups, etc. The governing partial differential equations (PDEs) that account for effect of Buongiorno model are converted in to nonlinear ordinary differential equations (ODEs) through suitable similarity variables. Further, approximate analytical technique such as Adomian Decomposition Method is beneficial to carry out the solution of the transformed governing equations and the significant nature of the contributing parameter for both the steady and unsteady case is presented via graphs. Moreover, the major contribution is; the Casson parameter along with suction/injection favors in the smooth enhancement in the velocity profiles and the fluid temperature also encouraged by the augmentation in Brownian and thermophoresis parameter.
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Bayamirova, Ryskol, Aliya Togasheva, Akshyryn Zholbassarova, and Manshuk Sarbopeyeva. "THE SYSTEM OF PRELIMINARY DISCHARGE OF RESERVOIR WATER ON DEPOSITS." Yessenov Science Journal 42, no. 1 (June 17, 2022). http://dx.doi.org/10.56525/zgwn4948.
Повний текст джерелаАнотація:
Abstract. Kazakhstan is one of the world's largest oil-producing regions. Among the explored and exploited deposits, the largest are Tengiz, Zhanazhol, Karachaganak, Uzen, Zhetybay, Kalamkas, Kumkol and a number of others. The extracted oils are very diverse in terms of their physical and chemical properties, the content of asphaltenes, resins and paraffins. Many of them contain significant amounts of carbon dioxide, sulfur and its compounds. Kazakhstan has extensive experience in the development, development and operation of such deposits and monitoring the associated environmental impact. It can be generalized and used in the further development of the industry. The composition of the products of all deposits is unique and is the determining element in the choice of technological schemes for its collection and preparation. Methods for increasing the depth of preparation, efficiency and reliability have been sufficiently studied, but due to changing requirements and existing achievements, the arrangement work is always creative in nature, and the technological solutions made are becoming more perfect. Water is the only component of well production that has natural contact with oil and must be returned to the natural environment. Waste waters include formation waters that are separated at almost all stages of oil treatment, and flushing waters introduced for desalting and final dehydration of oil. Before injection into the absorbing reservoir, they must be cleaned. To prevent the formation of stable emulsions, solid deposits and suspensions, a system of preliminary water discharge at the fields has been proposed. To intensify the processes of separating gas, water and mechanical impurities and gas from drained water, preserve the light, most valuable hydrocarbon components of oil, prevent oil and gas losses and environmental pollution, it is proposed to introduce a three-product multihydrocyclone into the system of preliminary formation water discharge at the fields. To intensify the processes of separating gas, water and mechanical impurities and gas from drained water, preserve the light, most valuable hydrocarbon components of oil, prevent oil and gas losses and environmental pollution, it is proposed to introduce a three-product multihydrocyclone into the system of preliminary formation water discharge at the fields. At the same time, the water quality improves to values suitable for injection into injection wells without additional treatment.. Keywords: oil and gas condensate field, reservoir water, emulsion, demulsifier, three-product multi-hydrocyclone, oil, gas, intensification, mechanical impurities, centrifugal pumps, water discharge, gravitational forces, desalination, dehydration, oil treatment.
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Khoo, Ying Wei, Hui Teng Tan, Yam Sim Khaw, Shi-Fang Li, and Khim Phin Chong. "First Report of Neoscytalidium dimidiatum Causing stem canker on Selenicereus megalanthus in Malaysia." Plant Disease, May 31, 2022. http://dx.doi.org/10.1094/pdis-03-22-0566-pdn.
Повний текст джерелаАнотація:
Selenicereus megalanthus (family Cactaceae), commonly known as yellow pitahaya is a new crop being planted commercially in Malaysia. In May 2021, stem canker symptoms with sign of black pycnidia formed on the surface of canker (30- to 55-mm in diameter) were observed on the stem of 80% of ‘yellow pitahaya’ plants in the field (~8 ha) located in the district Keningau of Sabah, Malaysia (5°20'53.1"N 116°06'23.0"E). The infected stems became rotted when black pycnidia formed. To isolate the pathogen, the symptom margin was excised into four small blocks (5 x 5 x 5 mm), and the blocks were surface sterilized based on Khoo et al. (2022) before plating on potato dextrose agar (PDA). Plates were incubated at 25°C for 7 days in the dark. Two isolates were obtained and were named Keningau and Keningau02. Powdery white mycelia were initially observed in two plates, and then became dark grey with age. Dark pigmentation in plates was observed after a week of incubation at 25°C in the dark. Arthroconidia (n= 30) were hyaline to dark brown, circular or cylindrical with round to truncate ends, with zero to one septum, measuring 8.9 x 5.6 µm in size. Conidia (n= 30) exuded in milky white cirrhus from pycnidia were one-celled, aseptate, oblong, measuring 10.3 × 4.6 µm in size. When reached the maturity stage, conidia were brown and septate. Genomic DNA from Keningau and Keningau02 were extracted from fresh mycelia based on Khoo et al. (2021) and Khoo et al. (2022). Amplification of the internal transcribed spacer (ITS) region of rDNA, translation elongation factor 1-α (TEF1) region and β-tubulin (TUB) genes were performed using ITS1/ITS4, EF1-728F/EF1-986R and T10/Bt2b primer sets, respectively (Carbone and Kohn, 1999; O’Donnell et al. 1997; White et al. 1990). The products were sent to Apical Scientific Sdn. Bhd. for sequencing. BLASTn analysis of the newly generated ITS (GenBank OK458559, OM649909), TEF1 (GenBank OM677768, OM677769) and TUB (GenBank OL697398, OM677766) indicated 99% identity to Neoscytalidium novaehollandiae strain CBS 122071 (GenBank MT592760). Phylogenetic analysis using maximum likelihood and Bayesian inference on the concatenated ITS-TEF1-TUB was constructed using IQ-Tree and MrBayes3.2.7. Neoscytalidium hyalinum, N. novaehollandiae and Neoscytalidium orchidacearum are reduced to synonymy with N. dimidiatum (Philips et al. 2013; Zhang et al. 2021). Although N. novaehollandiae is morphologically and phylogenetically similar to N. dimidiatum, but N. novaehollandiae produce muriform, Dichomera-like conidia that distinguish this species from other known Neoscytalidium species (Crous et al. 2006). No muriform, Dichomera-like conidia were observed in the Malaysia’ isolates. The pathogen was identified as N. dimidiatum based on molecular data and morphological characterization (Serrato-Diaz and Goenaga, 2021). Pathogenicity tests were performed based on Mohd et al. (2013) by injection inoculation of 0.2 ml of conidial suspensions (1 x 106 conidia/ml) from isolate Keningau to three 30-month-old yellow pitahaya stems using a disposable needle and syringe. Distilled water was injected into three mock controls. The inoculated yellow pitahaya plants were covered with plastics for 48 h and incubated at 25°C. The pathogenicity test was also performed using isolate Keningau02. All inoculated stems developed symptoms as described after 6 days post-inoculation, whereas no symptoms occurred on controls, thus fulfilling Koch’s postulates. The experiments were repeated two more times. The reisolated fungi were identical to the pathogen morphologically and molecularly. To our knowledge, this is the first report of N. dimidiatum causing stem canker on S. megalanthus in Malaysia. Our findings serve as a warning for the authorities and farmers that the disease threat has appeared in the Malaysian yellow pitahaya production.