On the number of contacts of a floating polymer chain cross-linked with a surface adsorbed chain on fractal structures

We study the interaction problem of a linear polymer chain, floating in fractal containers that belong to the three-dimensional Sierpinski gasket (3D SG) family of fractals, with a surface-adsorbed linear polymer chain. Each member of the 3D SG fractal family has a fractal impenetrable 2D adsorbing surface, which appears to be 2D SG fractal. The two-polymer system is modelled by two mutually crossing self-avoiding walks. By applying the Monte Carlo Renormalization Group (MCRG) method, we calculate the critical exponents $\phi$, associated with the number of contacts of the 3D SG floating polymer chain, and the 2D SG adsorbed polymer chain, for a sequence of SG fractals with $2\le b\le 40$. Besides, we propose the codimension additivity (CA) argument formula for $\phi$, and compare its predictions with our reliable set of the MCRG data. We find that $\phi$ monotonically decreases with increasing $b$, that is, with increase of the container fractal dimension. Finally, we discuss the relations between different contact exponents, and analyze their possible behaviour in the fractal-to-Euclidean crossover region $b\to\infty$.Comment: 15 pages, 3 figure

Coexistence of trisomy 12 and del(13)(q14.3) in two patients with chronic lymphocytic leukemia

We describe two patients with diagnosis of chronic lymphocytic leukemia (CLL) in whom interphase fluo­rescence in situ hybridization (FISH) analysis revealed trisomy 12 and del(13)(q14.3) occurring in the same clone. These abnormalities are rarely seen together and the prognostic relevance of their coexistence is still unclear. According to some data, a probable adverse prognosis for this group of patients is suggested. Our patients have been in a stable phase of the disease for more than one year since the given abnormalities were documented in their karyotypes. Further study is necessary to determine the prognostic significance of coexistence of these abnormalities in CLL patients

In Vitro Toxicity of Fungicides with Different Modes of Action to Monilinia laxa Isolates in Serbia

Sensitivity of M. laxa isolates originated from mummified plum fruits was tested to benomyl, iprodione, trifloxystrobin, tebuconazole and pyrimethanil. Mycelia growth inhibition on growth medium was monitored and susceptibility parameters were determined using probit analysis. The EC50 values for benomyl were the highest ranging from 0.123 to 0.901 mg L-1 followed by iprodione (0.125-0.301 mg L-1), trifloxystrobin (0.004-0.009 mg L-1), tebuconazole (0.014-0.041 mg L-1) and pyrimethanil (0.148-0.191 mg L-1). Medium resistant level of M. laxa isolates to benomyl was established. The isolates tested showed a normal susceptibility to iprodione, trifloxystrobin, tebuconazole and pyrimethanil

Alterations in amount of chlorophyll as indicator of resistance for Chenopodium album L. and Amaranthus retroflexus L. to atrazine

Resistance in weeds, as a natural phenomenon or caused by herbicide application, is a major challenge for science and agricultural production. Nevertheless, a small number of plants is naturally resistant or has developed a resistance caused by a natural selection process. Stress factors such as the use of herbicides results in development of resistant species by selection pressure. Slow uptake and translocation of herbicides, faster metabolization and/or the isolation of "foreign" molecules in certain tissues, structural changes in the target sites and others influencing factors are mechanisms of survival. Many research projects have been trying to find adequate physiological or morphological parameters for the determination of weed resistance to herbicides. For herbicides inhibiting photosynthesis, the most reliable parameters for the determination of weed resistance are bleaching effects as well as changes in plant dry mass and chlorophyll fluorescence. Therefore, the main objective of this study was to test the validity of measuring changes in the amount of chlorophyll as an indicator for the sensitivity/resistance of Chenopodium album L. and Amaranthus retroflexus L. to atrazine. The resistance was investigated using susceptible weed populations from Great Britain as well as weed populations from Great Crljeni and Belgrade. The total amount of chlorophyll was determined by a non-destructive method (SPAD meterchlorophyll readings obtained with the Minolta-502 SPAD meter) and a destructive methode (extraction by dimethylphormamide). The validity of both methods was evaluated and the amount of chlorophyll and its fluorescence was correlated. Results showed that by measuring the amount of chlorophyll in both ways it was possible to distinguish between sensitive and resistant weed populations. A correlation between the amount of chlorophyll and changes in fluorescence could not be not confirmed

Application of grain baits to control common vole Microtus arvalis (Pallas, 1778) in alfalfa crops, Serbia

In order to compare the efficacies of conventional (cholecalciferol and bromadiolone) and new (sodium selenite) rodenticides, applied in the grain bait formulation on the whole-grain of wheat (Triticum aestivum) and triticale (Triticasecale) in alfalfa crops, experiments were conducted at two sites near Belgrade, Serbia, in the spring of 2009, using a standard EPPO method. The presence of rodent populations, their spatial distribution and density indices were evaluated by pretreatment census and rodenticide efficacy by counting active holes, 14 and 28 days after treatment. The average Microtus arvalis numbers of 158/ha and 184/ha were found to cause 7.4% and 9.6% alfalfa green biomass yield decreases, respectively. Twenty-eight days after treatment, the average efficacy of grain bait formulation (on wheat and triticale grains) of sodium selenite and cholecalciferol was 81%, while bromadiolone which had a higher efficiency, 85%, in the control of the common vole in alfalfa crops. The analysis of variance (ANOVA) showed that the origin of active substances, bases and associated interactions a.s x based on the efficacy-investigated grain baits did not have a statistically significant impact on the expression efficiency of the tested baits. Triticale grains can be used as carriers of active substances, sodium selenite, cholecalciferol or bromadiolone in preparation baits. Control of M. arvalis with the new rodenticide, sodium selenite, gave efficacy results about equal to that of cholecalciferol and bromadiolone and, therefore, provided a possible alternative rodenticide for vole control in alfalfa