Synthesis and characterization of polyvinyl alcohol / lead sulfide nanocomposite

The nanocomposite consisting of lead sulfide (PbS) nanoparticles (NPs) with average diameter of 2.6 nm and polyvinyl alcohol (PVA) were synthesized using colloidal chemistry methods. The PbS/PVA nanocomposites were characterized using optical, structural and thermal techniques. The presence of the PbS NPs in the PVA matrix induced the increase of the crystallization temperature and enthalpy of crystallization.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Evaluation of immunogenic properties of monovalent and polyvalent inactivated bovine virus diarrhea virus (BVDV) vaccines

This study is aimed at evaluating the immunogenicity of two inactivated (mono- and polyvalent) vaccines containing bovine virus diarrhea virus (BVDV) reference and field strains. Three experimental groups were formed: 10 calves vaccinated twice (days 1 and 28) subcutaneously (s/c) with 2 ml of inactivated polyvalent vaccine per animal (Group 1); 10 calves vaccinated twice (days 1 and 28) subcutaneously (s/c) with 2 ml of inactivated monovalent vaccine per animal (Group 2) and 9 unvaccinated calves (Control, Group C). Blood sera were obtained from immunized animals (standard procedure: on days 0, 14, 28, 42 and 56 post-immunization). Geometric mean titer (GMT) values for BVDV neutralizing antibodies were substantially higher in blood sera of calves receiving the inactivated monovalent vaccine. The immune response developed more rapidly in calves immunized with the monovalent vaccine

A regularization algorithm for matrices of bilinear and sesquilinear forms

We give an algorithm that uses only unitary transformations and for each square complex matrix constructs a *congruent matrix that is a direct sum of a nonsingular matrix and singular Jordan blocks.Comment: 18 page

Canonical matrices of bilinear and sesquilinear forms

Canonical matrices are given for (a) bilinear forms over an algebraically closed or real closed field; (b) sesquilinear forms over an algebraically closed field and over real quaternions with any nonidentity involution; and (c) sesquilinear forms over a field F of characteristic different from 2 with involution (possibly, the identity) up to classification of Hermitian forms over finite extensions of F. A method for reducing the problem of classifying systems of forms and linear mappings to the problem of classifying systems of linear mappings is used to construct the canonical matrices. This method has its origins in representation theory and was devised in [V.V. Sergeichuk, Math. USSR-Izv. 31 (1988) 481-501].Comment: 44 pages; misprints corrected; accepted for publication in Linear Algebra and its Applications (2007

Pulsed Laser Deposition of BaTiO3 on PVDF substrate

Piezoelectric materials play an important role in development of advanced Micro-electromechanical systems (MEMS) and Nano-electro-mechanical systems (NEMS). Their applications span the aero-space industry, communications, defense systems, national security, health care, information technology and environmental monitoring. Materials used in MEMS/NEMS mustsimultaneously satisfy numerous requirements for chemical, structural, mechanical and electrical properties. Although traditionally MEMS in particular have relied on silicon, the materials used in MEMS/NEMS are becoming more heterogeneous. Taking into account that materials nanostructuring can produce unique mechanical, electrical and piezoelectric properties, in this article the investigation of pulsed laser deposition of BaTiO3 on PVDF substrate has been performed. The titanium-saphire laser operated at 800 nm with 40-fs pulse duration and 1 kHz repetition rate was focused onto a mechanically activated BaTiO3 target. Deposition on PVDF substrate was done at an oxygen partial pressure of 10-7 Torr using a laser pulse frequency of 1 kHz at room temperature. The crystal structure and the microstructure of the films were examined using an X-ray diffractometer and scanning electron microscope, while the surface morphology was observed by atomic force microscopy.It was found that pulsed laser deposition of BaTiO3 on PVDF substrate offers a new set of opportunities for development of advanced flexible piezo-films for the next generation of NEMS

Uticaj nivoa proteina u hrani i dužine trajanja tova na randman i mere konformacije trupova pilića

This study analyses the effect of different protein levels in broiler feeds (supplemented with protease) and different lengths of fattening period on some parameters related to dressed carcass quality. Medium-growing Master Gris broiler chickens were used in a fattening trial lasting 63 days. At slaughter, dressing percentages and abdominal fat percentages were determined based on traditionally dressed carcass weights and abdominal fat weights of broilers at 49 and 63 days, and conformation indices were calculated based on absolute conformation measurements. Results showed that dietary treatment had an effect only on one relative conformation measurement - body weight/shank length in chickens at 49 days, as control broilers had higher values of this index compared to chickens receiving feeds containing reduced levels of crude protein and protease supplementation (0.2% or 0.3%). Length of fattening period affected almost all studied parameters, except breast angle, dressing percentage of traditionally dressed carcass and abdominal fat percentage.U radu je analiziran uticaj različitog nivoa proteina u hrani za tov pilića (uz dodatak enzima proteaze) i dužine trajanja tova na neke parametre kvaliteta obrađenih trupova. U ogledu je korišćen medium-growing linijski hibrid Master Gris, a ogled je trajao 63 dana. Na liniji klanja, na osnovu mase klasično obrađenog trupa i mase abdominalne masti pilića uzrasta 49. i 63.dana tova utvrđen je randman klasimično obrađenog trupa i udeo abdominalne masti, a na osnovu apsolutnih mera konformacije izračunati su indeksi mera konformacije. Rezultati ogleda su pokazali da je uticaj ispitivanih obroka ispoljio efekat samo na jednu relativnu meru konformacije trupova - telesna masa/dužina piska kod pilića starosti 49.dana, jer su pilići iz kontrolne grupe imali veću vrednost ovog indeksa u odnosu na piliće koji su hranjeni smešama sa nižim nivoima sirovih proteina, uz dodatak enzima proteaze (0,2% ili 0,3%). Različita dužina trajanja tova uticala je na skoro sve ispitivane parametre, izuzev na veličinu grudnog ugla, randman klasično obrađenog trupa i udeo abdominalne masti

Paradigm of coinfection with viral and bacterial agents causing bovine respiratory disease complex (BRDC) in Central Serbia

Viral and bacterial agents causing bovine respiratory disease complex (BRDC) were examined over a five-year period (2015-2019). Thirty-eight farms of beef and dairy cattle from Central Serbia which showed symptoms of BRDC were observed. A total of 118 nasal swab specimens collected from diseased bullocks (n=55), cows (n=18) and calves (n=45) were chosen for the isolation of bacteria and identification by aerobic cultivation. The most commonly isolated bacterial pathogen was Pasteurella multocida (72.88% positive samples). Disk-diffusion method (antibiogram) showed that Amoxiclav and Enrofloxacin were the most efficient antibiotics against Pasteurella multocida isolates (66.67% and 54.17%, respectively). From all examined samples, using the Real Time RT-PCR and PCR methods, we determined the genome sequences of bovine respiratory syncytial virus (BRSV-34.78% of tested samples (8/23), bovine viral diarrhea virus (BVDV, in 34.37% (11/32) and Mycoplasma spp. in 33.33% (8/24). The genome of BoHV-1 virus was not detected in any of the 19 samples tested by Real Time PCR method.Publishe

Etiopathogenesis and economic significance of bovine respiratory disease complex (BRDC)

BRDC is the most expensive disease of fattening cattle throughout the world. The reasons for this are high morbidity and mortality, weight loss, reduced food utilization, reduced quality of carcasses and extensive measures of prophylaxis and therapy. BRDC is caused by a substantial number of pathogens (viruses and bacteria), with predisposing risk factors from the ambient and host. Calves are at the highest risk of developing BRDC shortly after shipping. Lighter-weight calves appear to be at greater risk, although this has not been consistent. The complexity of BRDC makes it difficult to define the role of individual factors that predispose to or cause the disease. Stress factors may be 'necessary, but not sufficient', but they require additional effects to cause the disease. Increasing the production of meat and milk worldwide would be sustainable by improving the prevention and control of BRDC

Piezoelectric polymer/ceramic nanostructures for mechanical energy harvesting

Vibration-based mechanical energy is one of the most accessible energy source in the surroundings. Harvesting this type of energy exhibits a great potential for remote/wireless sensing, charging batteries, and powering electronic devices. Piezoelectric and ferroelectric materials, including PZT, BaTiO3, ZnO, polyvinylidene fluoride (PVDF), etc., can be used for converting ambient mechanical energy into electricity. Based on these materials, a variety of micro- or nanoelectromechanical systems can be developed for harvesting energies from random vibrations, mechanical waves, or body movements like walking, running, or typing. Recent investigations on nanocomposites of electroactive ceramics and ferroelectric polymers exploit this approach in order to produce new multifunctional materials for mechanical energy harvesting. Taking into account that mechanical activation is one of the methods for modification of physico-chemical properties of the filler, in this study we investigate the influence of mechanical activation of ZnO particles on structural properties of ZnO/polyvinylidene fluoride nanocomposites. The nanocomposite films were prepared by solution casting method and investigated by X-ray diffraction (XRD) method and Raman spectroscopy, while the microstructure morphology has been analyzed by scanning electron microscope (SEM). Presented results will enable optimization of PVDF processing techniques for the production of new mechanical energy harvesting devices

Analiza kvaliteta trupova mladih bikova simentalske rase prema EU standardu

Domestic spotted cattle of Simmental breed with a combined production capacity is mostly grown in the Republic of Serbia. Considering the Serbia's potential and tradition in production of quality beef meat as food for human consumption and raw material in the food industry and the demand of the EU market, imposes the need for changing the present and adopting new regulations. The quality of the slaughtered animals is a subject of interest, of both primary production and meat industry. Procedure of classification of carcasses is performed in slaughterhouses immediately after a veterinary examination and measurement of carcasses weight. This paper examines the quality of young cattle carcasses in a slaughterhouse in the Raska district, according to the standard applied in the EU but not in Republic of Serbia. Examination has been conducted on 80 cattle carcasses (young bulls) weighing 450 - 550 kg. For the quality evaluation and grading of meat the following parameters according to the European standard for the classification of cattle carcasses (SEUROP) were used: weight of the animal, the category of a slaughtered animal according to the age and physiological state, slaughter weight / carcass weight and randman, i.e. the conformation of the carcass, development of the muscles of the carcass as well as the development of basic parts (leg, back and shoulder) and the degree of carcass fat tissue coverage.Domaće šareno goveče u tipu simentalca je rasa goveda kombinovanih proizvodnih sposobnosti koja se najviše gaji u Republici Srbiji. Posmatrajući potencijal i tradiciju naše zemlje u proizvodnji kvalitetnog goveđeg mesa kao namirnice za ishranu ljudi i sirovine za preradu u prehrambenoj industriji s jedne strane, i potreba tržista EU sa druge strane, nameće se potreba za menjanjem postojećih i donošenjem novih propisa. Kvalitet trupova zaklanih životinja je predmet interesovanja, kako primarne proizvodnje, tako i industrije mesa. Postupak klasiranja trupova odnosno polutki sprovodi se u klanicama neposredno nakon veterinarskog pregleda i utvrđivanja mase trupa. U radu je ispitan kvalitet trupova junadi, zaklanih u jednoj klanici u Raškom okrugu, prema standardu koji se primenjuje u zemljama Evropske Unije a koji se još ne primenjuje u Republici Srbiji. Ispitivanje je sprovedeno na 80 trupova junadi (mladih bikova) telesne mase 450 - 550 kg. Za procenu kvaliteta i klasiranje mesa u trupovima korišćeni su parametri, prema Evropskom standardu za klasiranje trupova goveda SEUROP: masa životinje, kategorija zaklane životinje shodno starosti i fiziološkom stanju, klanična težina/masa trupa i randman, konformacija trupa tj. razvijenosti mišića trupa kao i razvijenosti osnovnih delova (but, leđa i plećka) i stepen prekrivenosti trupa masnim tkivom