Bacterial biofilm on PLA film and methods of its identification

This paper presents a brief characterization of bacterial biofilm, formed on polylactide, ecologically important biodegradable material. The concept of bacterial biofilm was explained, including the process of its formation as well as the structure and model of functioning in a biological environment. Three methods of its determination and documentation by spectrophotometric measurement, live/dead test using fluorescence microscope and surface structure analysis using scanning electron microscope were presented

About the determination of critical exponents related to possible phase transitions in nuclear fragmentation

We introduce a method based on the finite size scaling assumption which allows to determine numerically the critical point and critical exponents related to observables in an infinite system starting from the knowledge of the observables in finite systems. We apply the method to bond percolation in 2 dimensions and compare the results obtained when the bond probability p or the fragment multiplicity m are chosen as the relevant parameter.Comment: 12 pages, TeX, 4 figure

New biodegradable polylactide material with antimicrobial properties

This study aimed to investigate the bactericidal, fungicidal and non-phytotoxic properties of vapor permeable polylactide films containing five different concentrations (in the range of 0.2–1.0%) of thiabendazole. All films showed bactericidal properties on Staphylococcus aureus and Escherichia coli. Thiabendazole introduced into polylactide affected the antifungal activity of the materials containing 0.8 and 1.0% thiabendazole. The films containing thiabendazole were characterized by increased permeability. The vapor permeability of the film increased with the increase of the biocide content in the composites. The new materials had no a negative effect on the growth and development of monocotyledonous and dicotyledonous plants. It has been shown that the presence of thiabendazole increases the water vapor permeability of polylactide films. The obtained materials are biodegradable and can be used in horticulture and agriculture to protect plants against pathogens. The use of films with biocide properties will reduce the use of plant protection products. This is particularly important due to the need to protect biodiversity in the ecosystem of agricultural soils

Localization Properties of Two Interacting Electrons in a Disordered Quasi One-Dimensional Potential

We study the transport properties of two electrons in a quasi one-dimensional disordered wire. The electrons are subject to both, a disorder potential and a short range two-body interaction. Using the approach developed by Iida et al. [ Ann. Phys. (N.Y.) 200 (1990) 219 ], the supersymmetry technique, and a suitable truncation of Hilbert space, we work out the two-point correlation function in the framework of a non-linear sigma model. We study the loop corrections to arbitrary order. We obtain a remarkably simple and physically transparent expression for the change of the localization length caused by the two-body interaction.Comment: 10 page

In vitro branched chain amino acid oxidation by porcine mammary tissue

Mammary secretory tissue from six (three each of parity 1 and 2) lactating sows (d 10 to 17 of lactation) was obtained via biopsy for in vitro incubation to determine CO2 production fr01TI individual branched chain amino acids. Carbon dioxide production levels as percentages of the 14C-labeled amino acid metabolized by the mammary tissue were 2.57, 1.86, and 4.07% for isoleucine, leucine, and valine, respectively (P\u3c .03). These results indicate that, in the lactating sow mammary gland, valine has the greatest oxidation rate of the branched chain amino acids.; Swine Day, Manhattan, KS, November 16, 199

The effects of BMD in lactation diets on sow and litter performance

One hundred forty-five multiparous sows were used in a performance trial to evaluate the use of BMD® (bacitracin methylene disalicylate) on sow and litter performance during lactation in a herd with no previously documented history of Clostridium perfringens type C or D. Between day 96 and 100 of gestation, sows were allotted to one of two dietary treatments, either a diet containing 250 g/ton of BMD or the control diet with no antibiotic. Sows were fed the experimental diets until weaning (approx. 20 d). Litters were equalized to approximately 10 pigs per sow within 48 hrs postfarrowing. Piglets were transferred only within treatment. Piglets on sows fed the BMD treatment had a reduced incidence of diarrhea (P=.10); however, the antibiotic had no effect on sow or litter performance.; Swine Day, Manhattan, KS, November 18,199

Hole-burning experiments within solvable glassy models

We reproduce the results of non-resonant spectral hole-burning experiments with fully-connected (equivalently infinite-dimensional) glassy models that are generalizations of the mode-coupling approach to nonequilibrium situations. We show that an ac-field modifies the integrated linear response and the correlation function in a way that depends on the amplitude and frequency of the pumping field. We study the effect of the waiting and recovery-times and the number of oscillations applied. This calculation will help descriminating which results can and which cannot be attributed to dynamic heterogeneities in real systems.Comment: 4 pages, 8 figures, RevTe

Properties of low-lying states in a diffusive quantum dot and Fock-space localization

Motivated by an experiment by Sivan et al. (Europhys. Lett. 25, 605 (1994)) and by subsequent theoretical work on localization in Fock space, we study numerically a hierarchical model for a finite many-body system of Fermions moving in a disordered potential and coupled by a two-body interaction. We focus attention on the low-lying states close to the Fermi energy. Both the spreading width and the participation number depend smoothly on excitation energy. This behavior is in keeping with naive expectations and does not display Anderson localization. We show that the model reproduces essential features of the experiment by Sivan et al.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. Let

Effects of Cordyceps Mushroom Powder on Nursery Pig Performance

One hundred sixty crossbred pigs (Duroc × (York × Landrace)) weaned at 18.8 d of age and weighing an average of 13.1 lb were used in a 35-day growth trial to evaluate Cordyceps mushroom powder as potential alternative to carbadox in nursery pig diets. Pigs were divided by weight, sex, litter, and assigned to body weight (BW) blocks. Within BW blocks, sex ratios were constant in each pen. Each pen within a BW block was randomly assigned a dietary treatment. Growth performance was analyzed using BW, average daily gain (ADG), average daily feed intake (ADFI), and feed conversion as feed-to-gain (F:G). Pigs were blocked by weight with 5 or 6 pigs per pen and there were 6 pens per treatment. There were 5 diets used in the study: a negative diet or a positive control (carbadox, 50 g/ton); 300 or 600 ppm mushroom powder, and a step-down treatment (900, 900, 450, 300, and 150 ppm mushroom powder during weeks 1, 2, 3, 4, and 5, respectively). At various points of the study, pigs fed the 300 ppm and the step-down mushroom powder treatments tended to have improved (P \u3c 0.10) growth performance compared with those fed the negative control diet. During Phase 4 of the study, pigs fed carbadox had greater ADG (P \u3c 0.02) and improved feed efficiency (P \u3c 0.09) over pigs fed the negative control diet. However, overall data showed that there were no statistical differences among treatments (P \u3e 0.05). In summary, pigs fed 300 ppm mushroom powder or the step-down treatment showed comparable results to pigs fed carbadox. However, future research is needed under a greater disease pressure to show mushroom powder’s full potential as an alternative to antibiotics

Evaluation of modified potato starch in diets for the early-weaned pig

Two growth trials were conducted to compare the effectiveness of replacing either corn or lactose with modified potato starches in diets for conventionally and early-weaned pigs. In Exp. 1, 198 pigs (initially 9.4lb and 19 d of age) were used to determine if modified potato starch (potato starch 1) can replace a portion of the lactose in a high nutrient dense diet. Pigs were allotted by weight, gender, and ancestry to each of six dietary treatments with either five or six pigs per pen and six pens per treatment. The control diet contained 10% dried whey (7.2% lactose), 7.5% spray-dried porcine plasma, 2.5% select menhaden fish meal, and 1.75% spray-dried blood meal. Additional treatments were formulated by adding 7 or 14% modified potato starch or lactose in place of com. A positive control diet also was formulated containing 29% dried whey (providing the same amount of lactose as the 10% dried whey plus 14% lactose diet). All diets were formulated to contain 1.5% lysine, and .90% Ca, .80% P, and 17.88% soybean meal and were fed in a meal form. From day 0 to 14 postweaning, increasing dietary lactose tended to linearly improve ADG and ADFI. Added potato starch did not improve ADG compared with pigs fed the control diet, but ADFI increased linearly with increasing potato starch. In Exp. 2, 180 pigs (8.5 lb and 14 d of age) were used to evaluate the effects of two modified potato starches (potato starch 1 or potato starch 2,a further hydrolyzed potato starch with a greater percentage of sugars as either glucose or maltose as a replacement for either com or lactose in a segregated early-weaning diet (SEW). Pigs were fed a control diet containing 15% dried whey, 12% added lactose, 6% porcine plasma, and 6% select menhaden fish meal. Modified potato starch 1 or 2 (12 %) replaced either corn or the added lactose on an equal weight basis. From d 0 to 7 postweaning, pigs fed the modified potato starch 1 had greater ADG and ADFI than those fed modified potato starch 2. Pigs fed diets with either starch substituted for corn had greater ADG than those fed diets with either starch substituted for lactose. From d 0 to 14 and d o to 21, pigs fed diets containing either modified potato starch substituted for corn tended to have greater ADG than those fed the control diet. This appeared to be the result of greater feed intake of pigs fed the diets containing either starch substituted for corn compared with those fed the control diet or diets containing either starch substituted for lactose. Pigs fed diets with either modified starch substituted for lactose had similar ADG as those fed the control diet. In conclusion, these results suggest that potato starch can improve growth performance of pigs when substituted for corn and can replace a portion of the lactose in an SEW diet without adversely affecting performance.; Swine Day, Manhattan, KS, November 17, 199