On a initial value problem arising in mechanics

We study initial value problem for a system consisting of an integer order and distributed-order fractional differential equation describing forced oscillations of a body attached to a free end of a light viscoelastic rod. Explicit form of a solution for a class of linear viscoelastic solids is given in terms of a convolution integral. Restrictions on storage and loss moduli following from the Second Law of Thermodynamics play the crucial role in establishing the form of the solution. Some previous results are shown to be special cases of the present analysis

Production of Plant Protection Agents in Medium Containing Waste Glycerol by Streptomyces hygroscopicus: Bioprocess Analysis

The surplus of waste glycerol, by-product of the biodiesel production process, is available at the global market. Some species of the genera Streptomyces have the ability to assimilate glycerol and convert it into valuable metabolic products. In the present study, the ability of Streptomyces hygroscopicus to assimilate waste glycerol and convert it into metabolic compounds with antifungal activity against four phytopathogenic fungi obtained from apple fruit samples expressing rot symptoms, was investigated. Production of antifungal metabolites by S hygroscopicus was carried out in 3 l stirred tank bioreactor through 7 days. Fermentation was carried out at 27 degrees C with aeration rate of 1.5 vvm and agitation rate of 100 r.p.m. The aim of this work was to analyse bioprocess parameters and to determine at which stage of bioprocess the production of antifungal metabolites occurs. Activity of the cultivation liquid on two isolates of Alternaria alternate and two isolates of Fusarium avenaceum were determined every 12 h using in vitro well diffusion method. It was found that the maximum production of antifungal metabolites occurred at 108 hour of cultivation. Formed inhibition zones have shown that the produced antifungal metabolites have high efficacy on tested phytopathogenic fungi (inhibition zone diameter higher than 35 mm for all test organisms)

Determination of residues of sulfonylurea herbicides in soil by using microwave-assisted extraction and high performance liquid chromatographic method

A modified method for the analysis of nicosulfuron, rimsulfuron and prosulfuron was developed and validated by using microwave-assisted extraction (MAE) and ultra-performance liquid chromatography with diode array detection in the ultraviolet region (HPLC-UV-DAD). The most important experimental parameters of extraction procedure and HPLC-UV-DAD technique were optimised in respect to those sulfonylurea herbicides. High recoveries of the microwave-assisted extraction were obtained by using a dichloromethane-acetonitrile mixture (2:1 volume ratio) acidified with acetic acid (0.8 vol.%) with the addition of urea. The mean recoveries at three spiking levels ranged from 97.47 to 98.76% for nicosulfuron, 97.88 to 99.17% for rimsulfuron and from 97.91 to 99.83% for prosulfuron. The limits of detection of nicosulfuron, rimsulfuron and prosulfuron were 0.95, 0.91 and 0.89 mu g kg(-1), respectively. The accuracy of the developed method was confirmed by HPLC coupled with tandem mass spectrometry parallel analyses. The developed method was used to investigate the dissipation dynamics of sulfonylurea herbicides in the real field trials in Vojvodina Province, Serbia. The obtained half-lives were 0.05, 0.23 and 0.15 days for recommended dose application of nicosulfuron, rimsulfuron and prosulfuron, respectively. Low residues and short half-life in soil suggested that the risk to sensitive rotational crops after application of those sulfonylurea herbicides is low when they are used in the appropriate dosages

Optimization of cultivation medium for the production of antibacterial agents

Optimization of the cultivation medium for production of antibiotic effective against pathogenic bacteria Staphylococcus aureus using strain of Streptomyces spp. isolated from the environment represents the aim of this study. After the biosynthesis, the medium was analyzed by determining residual sugar and nitrogen, and the antibiotic activity was determined using diffusion-disc method. Experiments were carried out in accordance with the Box-Behnken design, with three factors varied on three levels (glucose: 10.0, 30.0 and 50.0 g/L; soybean meal: 5.0, 15.0 and 25.0 g/L; phosphates: 0.5, 1.0 and 1.5 g/L) and for the optimization of selected parameters Response Surface Methodology was used. The obtained model with the desirability function of 0.985 estimates that the lowest amounts of residual sugar (0.89 g/L) and nitrogen (0.24 g/L) and the largest possible inhibition zone diameter (21.88 mm) that with its antibiotic activity against S. aureus creates the medium containing 10.0 g/L glucose, 5.0 g/L soybean meal and 1.04 g/L phosphates

Karakterizacija sirodezmina izolovanih iz fitopatogene gljive Leptosphaeria maculans

The pathogenicity of phytopathogenic fungi is associated with phytotoxins, especially with their chemical nature and quantity. Sirodesmins are phytotoxins from the epipolythiodioxopiperazines group, produced by the fungus Leptosphaeria maculans, which are a cause of blackleg and stem canker in oilseed rape (Brassica napus L.). The aim of this work was to obtain a detailed chemical profile of sirodesmins in five fungal isolates (four from Vojvodina, Serbia, and one from the Centre for Agricultural Research, Rothamsted, UK). Sirodesmins showing different phytotoxicity on treated cotyledons of cv. Quinta were separated and detected by thin layer chromatography in all analysed isolates (L.m, C-3, St-5 and S-11) except K-113, which neither contained sirodesmin congeners nor did it exhibit activity. By use of high performance liquid chromatography coupled with tandem mass spectrometer, it was possible to identify total of 10 sirodesmins, together with their precursor-phomamide. It was found that the dominant epipolythiodioxopiperazines of the investigated L. maculans isolates were sirodesmin PL, sirodesmin C, and their de-acetylated derivatives.Patogenost fitopatogenih gljiva povezana je sa fitotoksinima, a naročito sa njihovom hemijskom prirodom i količinom. Sirodezmini su fitotoksini iz grupe epipolitiodioksopiperazina, koje proizvodi gljiva Leptosphaeria maculans, uzročnik suve truleži korena i raka stabla uljane repice. Cilj ovog rada bila je detaljna hemijska karakterizacija sirodezmina u pet izolata gljiva (četiri iz Vojvodine i jedan iz Velike Britanije, Centar za poljoprivredna istraživanja, Rothamsted). Kod svih ispitivanih izolata (L. maculans, C-3, St-3, S-11), osim K-113 (koji nije sadržao sirodezmine niti pokazivao aktivnost) tankoslojnom hromatografijom su razdvojeni i detektovani sirodezmini koji su pokazali različitu fitotoksičnost na tretiranim kotiledonima sorte Quinta. Primenom tečne hromatografije visoke efikasnosti, kuplovane sa tandemskim masenim spektrometrom, bilo je moguće identifikovati ukupno 10 sirodezmina, kao i njihov prekursor - fomamid. Utvrđeno je da su dominantni epipolitio-dioksopiperazini ispitivanih izolata L. maculans sirodezmin PL, sirodezmin C i njihovi deacetilovani derivati

First Report of Fusarium equiseti as the Causal Agent of Seed Rot of Matthiola longipetala in Serbia

Matthiola longipetala (Vent) DC, commonly known as "night-scented stock" or "evening stock" is the most widely cultivated species of the genus Matthiola in the family Brassicaceae. It is a common garden flower, available in a variety of colours, many of which are heavily scented and also used in floristry. An elevated incidence of Fusarium was observed during a routine quality control seed assay of M. longipetala obtained from a private production facility in Đurđevo, Serbia in 2018. To our knowledge, this is the first report of F. equiseti as a causal agent of seed rot on M. longipetala in Serbia

Chemical vapour deposition of diamond using low pressure flat combustion flame

Diamond coatings were deposited onto Mo and WC-Co Substrates using a low pressure premixed acetylene-oxygen flat flame by means of a special apparatus operating at 50 mbar. Uniform diamond coatings containing significant amounts of non-diamond carbon were deposited over areas of approximate to 7 cm(2) onto Mo substrates, the coating thickness after 1 h deposition amounted to approximate to 1 mu m. Upon machining an Al-12 % Si alloy under identical conditions, the diamond coated WC-Co cutting tool inserts showed 30 % less wear than the as-receivcd inserts

Supporting Students in Recovery on College Campuses: Opportunities for Student Affairs Professionals

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83159/1/StudentsInRecovery.pd