Thesis (M. Agric. (Plant Production)) -- University of Limpopo, 2019 / Phytonematicides have allelochemicals as active ingredients and could be highly phytotoxic on crops being protected against nematode damage. In order to avoid phytotoxicity, the application concentration, technically referred to as mean concentration stimulation point (MCSP), along with the application interval, have to be empirically established. The Curve-fitting Allelochemical Response Data (CARD) computer-based model was adopted at the Green Biotechnologies Research Centre of Excellence (GBRCE) for developing the MCSP. The MCSP is computed from the CARD-generated biological indices and was technically defined as a phytonematicide concentration that could manage the nematode population densities without causing phytotoxicity to the test crop and it is plant-specific. The MCSP and application interval had been empirically established for different crops, but they had not been established for sweet potatoes. Therefore, the objective of the study was to determine the MCSP for Nemarioc-AL phytonematicide on Meloidogyne javanica-infected sweet potato cv. ꞌBopheloꞌ and its application interval. Sweet potato cuttings were planted in 25-cm diameter plastic bags containing steam-pasteurised loam soil and Hygromix at 3:1 (v/v) ratio. Each plant was inoculated with 5 000 eggs and second-stage juveniles (J2) of M. javanica, with seven treatments, namely, 0, 2, 4, 8, 16, 32 and 64% Nemarioc-AL phytonematicide, arranged in a randomised complete block design, with five replicates. At 56 days after the initiation of treatment, the MCSP values for plant variables and plant physiology variables were 1.92 and 3.08% Nemarioc-AL phytonematicide, respectively. The overall sensitivity values for plant variables and plant physiology variables were 0 and 1 unit, respectively, showing that the sweet potato cv. ꞌBopheloꞌ was highly sensitive to the product. Nematode variables with increasing concentrations of Nemarioc-AL phytonematicide exhibited positive and quadratic relations. The life cycle of M. javanica and the derived MCSP were used to empirically establish the application interval. Briefly, the location and most materials and methods were as outlined above except that ‘weeks-per-month-of-30 days’, with the MCSP being applied on 0, 7.5, 15, 22.5 and 30 days (0, 1, 2, 3 and 4 weeks) serving as treatments, replicated eight times. At 56 days after the treatments, plant variables and increasing application interval exhibited positive quadratic relations with the average of 2.55 ‘week of-30-day-month’ translating to 19 days (2.55/4 × 30), with nematode variables exhibiting negative quadratic relationships. In conclusion, when the MCSP of Nemarioc AL phytonematicide on sweet potato cv. 'Bophelo' at 1.92% was applied every 19 days, it would not be phytotoxic, but it would be able to suppress nematode population densities of M. javanica. The MCSP for essential nutrient elements could be reduced to that of plant growth variables, since the products are not intended for use as fertilisers.

The purpose of this study is to characterize the metasomatism that has taken place as a result of the chemical incompatibility between mafic and metaultramafic bulk compositions during high-grade regional metamorphism in the Tobacco Root Mountains, southwest Montana. Metasomatism of these rocks took place by both diffusionand infiltration-dominated processes. The result of these processes are characterized mineralogically and geochemically in the rocks.

Indiana University-Purdue University Indianapolis (IUPUI) / Objective: This study synthesized electrospun polymer-based scaffolds containing ciprofloxacin (CIP) and doxycycline (DOX), as a scaffold mimic of Double Antibiotic Paste (DAP) and determined, in vitro, its mechanical properties, chemical composition, and antimicrobial effectiveness against multiple endodontic bacterium. Methods: Polydioxanone sutures (PDS) were dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFP), mixed with CIP/DOX (i.e., 50%), and electrospun under optimized conditions into fibrous scaffolds. Tensile testing was used to evaluate the mechanical properties. Antimicrobial efficacy was determined over time using aliquots collected at 1, 4, 7, 14 day and agar diffusion assays. Two-Way Anova. Significance P < 0.05. Results: Tensile strength (MPa) of the CIP/DOX scaffold did not show significant difference from the control (pure PDS). Elongation at break (%) did show a significant difference between CIP/DOX scaffolds and the control group. Young’s modulus of elasticity (MPa) showed a significant difference between CIP/DOX scaffolds and the control. CIP-containing scaffolds did not inhibit Gram-negative (F. nucleatum and P. gingivalis) bacteria as effectively when compared to Gram-positive bacteria (E. faecalis and S. gordina). DOX-containing scaffolds showed less inhibition against Gram-positive (E. faecalis and S. gordina) bacteria then Gram-negative bacteria (F. nucleatum and P. gingivalis). In combination, CIP/DOX scaffolds showed significant inhibition against G(-) and G(+) bacteria. Conclusion: Electrospun double antibiotic scaffold demonstrated increased antimicrobial efficacy proving the potential for future clinical use to disinfect the RCS in permanent immature necrotic teeth to aid in regenerative treatment and or in persistent infections.

I detta kandidatarbete genomförs en rigorös analys av tidigare experiment och behandlar effekterna av laserpulser på droppformeringen vid UPTS (Uppsala Pellet Test Station). Analysen består av att undersöka olika data som registrerats av både LineScan- och CCD-kameror och identifiera korrelationer mellan olika parametrar, samt utforska hur de påverkar droppformeringen och droppkvalitén. De varierande parametrarna var höjden på både STR-lasern och CCD-kameran, fördröjningen mellan laserpulserna och vibrationerna hos munstycket, pulslängden och intensiteten hos lasern. De identifierade korrelationerna var mellan olika pulslängder och viktade x-positionen, x-bredden, tidslinjerna mellan pelleterna och pelletstrålens 2D-profil. Dessutom hittades en korrelation mellan fördröjningen och den viktade x-positionen för pelleterna. För de andra parametrarna var det svårt att bekräfta korrelationer på grund av det stokastiska beteendet hos pelleterna.

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Indiana University-Purdue University Indianapolis (IUPUI) / A modified double-blind method of investigation was used in which the pulps of 52 monkey teeth were surgically exposed and left open to the oral environment for a period of 24 hours. One-half of the exposed pulps were treated with an antibiotic preparation and one-half with a pure starch control. The antibiotic compound consisted of erythromycin estolate 10 percent, streptomycin sulfate 10 percent, and starch q. s. as the vehicle. The teeth were extracted at 30 and 90 day intervals after treatment and histologically evaluated. Inflammation of a varying degree was observed in all of the teeth treated with either the antibiotic preparation or the starch control. However, those teeth treated with the antibiotic capping material exhibited much less inflammation than did the great majority of teeth treated with the starch control, in which abscess formation and necrosis were frequently observed. The pulps of those teeth treated with the antibiotic capping material demonstrated a decidedly more favorable reaction than did those pulps treated with the starch capping material. Calcific repair at the exposure site was not observed to be complete in any instance. The histologic findings for the antibiotic treated teeth were encouraging and warrant additional investigations of longer duration.

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No description available.

Taproot decline (TRD), caused by an undescribed species of Xylaria, is an emerging root disease of soybean in Mississippi. Xylaria sp. isolates were collected from soybean roots and used to characterize TRD distribution as well as optimal growth temperature, pathogenicity, alternative host range, in vitro pathogenicity, and fungicide sensitivity. The 24 selected Xylaria sp. isolates from the 2016 collection had a mean optimal growth temperature of 26.7°C, and were pathogenic to soybean; however, differences in virulence occurred among isolates. Five selected Xylaria sp. isolates produced stroma on six hosts: corn, cotton, peanut, rice, sorghum, and wheat. Xylaria sp. colonized corn, cotton, and soybean seed in vitro; however, only reduced germination in soybean. Three selected Xylaria sp. isolates were exposed to fungicide-amended potato dextrose agar with concentrations up to 100 ppm of commercial products typically used in soybean production systems. Xylaria sp. isolates were insensitive to all active ingredients except thiophanate-methyl.