Experimental verification of mathematical model of the heat transfer in exhaust system

A catalyst convertor has maximal efficiency when it reaches working tempera-ture. In a cold start phase efficiency of the catalyst is low and exhaust emissions have high level of air pollutants. The exhaust system optimization, in order to de-crease time of achievement of the catalyst working temperature, caused reduction of the total vehicle emission. Implementation of mathematical models in devel-opment of exhaust systems decrease total costs and reduce time. Mathematical model has to be experimentally verified and calibrated, in order to be useful in the optimization process. Measurement installations have been developed and used for verification of the mathematical model of unsteady heat transfer in ex-haust systems. Comparisons between experimental results and the mathematical model are presented in this paper. Based on obtained results, it can be concluded that there is a good agreement between the model and the experimental results

Analysis of interactions of lactobacilli with rat gut mucosa

Probiotici predstavljaju žive mikroorganizme koji, nakon unošenja u gastrointestinalni (GI) trakt, ostvaruju pozitivne efekte na zdravlje domaćina. Reakcija domaćina na unos probiotika u velikoj meri zavisi od sposobnosti bliske interakcije bakterija sa epitelnim ćelijama GI mukoze. S druge strane, s obzirom na nepoznatu antigenu prirodu unetih bakterija, kod imunokompromitovanog domaćina je prisutan rizik od imunske reakcije crevnog tkiva što može da dovede do narušavanja integriteta mukozne barijere i hronične inflamacije u GI traktu. Cilj istraživanja bio je ispitivanje efekta soja Lactobacillus fermentum BGHI14, alohtonog za GI trakt pacova, nakon peroralnog unosa u zdrave pacove i u pacove sa kolitisom indukovanim TNBS-om (trinitrobenzensulfonat). Metodološki, u eksperimentima su praćeni: telesna masa pacova i ekspresija iRNK za parametre inflamacije (IL-1β, TNFα, IL-17F), pokazatelje ćelijskog stresa (HSP70) i parametre uključene u održavanje integriteta mukoze (TJP1); zatim su rađene histološke i biohemijske analize i analiza sastava crevne mikroflore. Rezultati istraživanja su pokazali imunostimulišuće delovanje soja BGHI14 na nivou tkiva kolona nakon unosa u GI trakt zdravih pacova u prvih 16 dana peroralnog tretmana pacova. Iako se, histološki, sa produžetkom tretmana pacova sojem BGHI14 tokom narednih 12 dana, imunska reakcija u tkivu kolona povukla, nivoi iRNK za proinflamatorne IL-1β i TNFα citokine ostali su povišeni što ukazuje na rizik od nekontrolisane inflamacije u slučaju naknadnog oštećenja epitelne barijere kolona. U istraživanju je pokazano da je nakon imunostimulacije tkiva kolona sojem BGHI14, u slučaju indukcije kolitisa, ali uz nastavak tretmana sojem BGHI14 došlo do indukcije transkripcije iRNK za HSP70 protein, kako u ranoj (48 h) tako i u kasnoj (7 dana) akutnoj fazi kolitisa. Povećanje transkripcije Hsp70 gena, sudeći po histološkim i inflamatornim pokazateljima, kao i promenama telesnih masa pacova tokom eksperimenta, nije bilo praćeno pozitivnim delovanjem soja. S druge strane, prestanak tretmana sojem BGHI14 nakon indukcije kolitisa doveo je do manje izraženog pada telesnih masa životinja u poređenju sa kontrolnim pacovima sa kolitisom, iako bez pratećeg smanjenja inflamatorne reakcije u tkivu kolona, bar u kasnoj akutnoj fazi bolesti (sedam dana od indukcije)...Probiotics are life microorganisms that, after administration in gastrointestinal (GI) tract, excert positive effects on host’s health. Host reaction to probiotic administration largely depands on ability of bacteria to closely interact with epithelial cells of GI mucosa. On the other hand, considering the unknown antigenic nature of administered bacteria, in immune-compromised host there is a risk of immune reaction of gut tissue which could lead to disturbance of mucosal barrier integrity and chronic inflammation in GI tract. The aim of the study was to examine the effects of the strain Lactobacillus fermentum BGHI14, which is alochtonous to GI tract of rats, after peroral administration in healthy rats and in rats with TNBS (trinitrobenzenesulfonate)-induced colitis. Methodologically, following parameters were examined in experiments: body masses of rats and expression of mRNA of inflammatory cytokines (IL-1β, TNFα, IL-17F), as well as markers of cellular stress (HSP70) and barrier integrity maintenanace (TJP1); next histological and biochemical analyses and microflora profiling were performed. Results of the study indicated immune-stimulating effects of BGHI14 in colon tissue after administration in GI tract of healthy rats in first 16 days of peroral treatment of rats. Although, histologically, with prolongation of BGHI14 treatment of rats for next 12 days, immune reaction in colon tissue had retreated, mRNA levels of proinflammatory IL-1β and TNFα cytokines remained elevated which points to the risk of uncontrolled inflammation in the case of subsequent colon epithelial barrier damage. In research it was shown that after immunostimulation of colon tissue with BGHI14, in the case of colitis induction, but with sequel of treatment with bacteria, transcription of Hsp70 gene was induced, in early (48 h) as well as late (7 days) acute phase of colitis. The increase of Hsp70 gene transcription, according to histological and inflammatory markers, as well as body mass changes during the experiment, was not followed by positive action of the strain. On the other hand, the cessation of treatment with BGHI14 after colitis induction had led to less pronounced body mass decrease compared to control colitic rats, but without concomitant reduction in inflammatory scores in colon tissue, at least in late acute phase of disease (seven days from induction)..

Three-Dimensional Simulation of the McPherson Suspension System

Suspension system of a vehicle is one of the most important components of a vehicle that directly affects the safety, performance, noise level. Designing mechanisms of suspension system of the vehicle is a very complex task. At the beginning it is necessary to realize many requirements relating to the suspension system. McPherson suspension system is most commonly used on the front of the vehicle. Its application is most reflected in better movement of vehicles through the cornering as well as in a comfortable ride. Modern methods of construction of the system and its components involve the use of certain software packages. In this paper, using CATIA software package, numerical simulations were carried out for the most important parts of suspension. Finite element analysis was performed of the entire system to analyze effective stress and deformation changes in the function parameters in the analysis

Effects of soybean carbohydrates and lactobacillus helveticus bgra43 on metabolic processes in rat colon

Aim of this work was to assess the metabolic and physiological changes that occurred in the hind gut of rats after feeding with soybean carbohydrates alone and in combination with Lactobacillus helveticus BGRA43. Wistar rats were gavaged with soybean flour for 28 days. The parameters assessed included fecal volatile organic compounds, and L-lactate, reducing sugars, proteins, ammonia and water levels in the colonic lumen. The presence of lactic acid (LAB), sulfate reducing (SRB) and methanogenic bacteria was assessed by semi-quantitative PCR. Malondialdehyde levels as well as lymphoid tissue size in ileal and colonic mucosa were also evaluated. On the basics of the results obtained, correlation network was created, setting the parameters tested in research in two metabolic groups: saccharolytic and proteolytic fermentation group. The principal finding of the study is a negative correlation between oral administration of BGRA43 and increase of parameters related to carbohydrate fermentation in the gut, and a positive correlation to factors related to proteolytic fermentation. On the contrary, soybean carbohydrates were correlated with increased values of factors related to carbohydrate catabolism. Different effects of BGRA43 and soybean carbohydrates on metabolic processes in colonic lumen indicate the possibility of applying the BGRA43 in alleviating the gastrointestinal symptoms occurring after consuming hardly digestible carbohydrates

Contribution to identification of mechanical characteristics of passenger motor vehicle’s drum brakes

Na temelju provedenih analiza, dokazano je da ne postoji opće prihvaćena metoda ocjene karakteristika i izlaznih parametara mehanizama bubanj kočnica. U radu su prikazana eksperimentalna istraživanja podsustava bubanj kočnica s ulaznom vrijednosti-tlakom kočione tekućine u cilindru kočnice i izlaznom vrijednosti-kočnim momentom. Dobiveni rezultati su pokazali da je između izlaza i ulaza postojalo vrijeme kašnjenja, zbog odgovora mehanizma bubanj kočnice. To ukazuje na nedostatak utvrđivanja performansi kočnica u vremenskoj domeni, jer u usporedbi nisu adekvatna uzbuda i odgovor sustava. Stoga se u analizi podsustava bubanj kočnice promatra dinamički mod. Dinamička analiza određuje ponašanje sustava u prijelaznom razdoblju. Uz već poznate prijenosne karakteristike sustava, njegov odgovor može biti određen u odnosu na navedene ulaze, uzbude, što je dobar temelj za određivanje korelacija između rezultata dobivenih različitim metodama identifikacije i pod različitim uvjetima ispitivanja.Based on the conducted analyses, it has been proven that there is no generally accepted method for evaluation of characteristics and output parameters of drum brake mechanisms. Experimental research of the drum brake subsystem with brake fluid pressure in the brake cylinder as input quantity and brake torque as output quantity is presented in the paper. The obtained results show that there is a time delay between the output and input due to the response of the drum brake mechanism. This points to the deficiency of determination of brake performance in time domain, because, in comparison, excitation and response of the system are not adequate. Hence, the dynamic mode is observed in the analysis of the drum brake subsystem. Dynamic analysis determines the behaviour of the system in transient period. With previously known transfer characteristics of a system, its response can be determined in relation to the specified inputs (excitations), which is a good basis for determination of correlation between the results obtained by different methods of identification and under different test conditions

Efekat imunostimulišućeg soja roda Limosilactobacillus kod pacova sa kolitisom izazvanim trinitrobenzensulfonatom (TNBS)

The aim of the study was to test the potential of immunostimulating Limosilactobacillus fermentum BGHI14 strain to reduce the damage of colon tissue in rats with 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis. Wistar rats were treated with L. fermentum BGHI14 in the regime of preventive, therapeutic and continuous treatment 22 days prior to and/or 7 days after the administration of TNBS. After sacrifice, the colon tissue samples were taken for RNA isolation, gene expression analysis, histopathological analysis, and malondialdehyde measurement. Judging from the body weights, histopathological scores, malondialdehyde levels and transcription of IL-1β and Tight junction protein 1 (Tjp-1) coding genes, preventive and therapeutic treatment proved to be the most protective in the applied conditions. On the other hand, continuous treatment did not affect the intensity of tissue damage. Considering these results, we discussed the possible mechanisms which might stand behind the protective action of immunostimulating probiotic bacteria in the case of mucosal barrier damage.Cilj ovog istraživanja je bio da se ispita potencijal imunostimulišućeg soja Limosilactobacillus fermentumBGHI14 da smanji oštećenje tkiva debelog creva kod pacova sa kolitisom izazvanim 2,4,6-trinitrobenzensulfonskom kiselinom (TNBS). Pacovi Wistar soja su tretirani sojem L. fermentumBGHI14 u režimu preventivnog, terapijskog i kontinuiranog tretmana 22 dana pre i/ili 7 dana nakon primene TNBS. Nakon žrtvovanja, uzorci debelog creva su sakupljeni za izolaciju RNK, analizu ekspresije gena, histopatološke analize i merenje malondialdehida. Na osnovu telesnih težina pacova, histopatološih rezultata, nivoa malondialdehida i transkripcije IL-1β citokina i proteina tesnih međućelijskih veza (Tjp-1), preventivni i terapijski tretman su se pokazali kao najefikasniji u primenjenim uslovima. S druge strane, kontinuirano lečenje nije uticalo na intenzitet oštećenja tkiva. Uzimajući u obzir ove rezultate, razmotreni su mogući mehanizmi koji stoje iza zaštitnog delovanja imunostimulišućih probiotičkih bakterija u slučaju oštećenja mukozne barijere

Effect of immunostimulating Limosilactobacillus strain in rats with trinitrobenzenesulfonate (TNBS)-induced colitis

The aim of the study was to test the potential of immunostimulating Limosilactobacillus fermentum BGHI14 strain to reduce the damage of colon tissue in rats with 2,4,6trinitrobenzenesulfonic acid (TNBS)-induced colitis. Wistar rats were treated with L. fermentum BGHI14 in the regime of preventive, therapeutic and continuous treatment 22 days prior to and/or 7 days after the administration of TNBS. After sacrifice, the colon tissue samples were taken for RNA isolation, gene expression analysis, histopathological analysis, and malondialdehyde measurement. Judging from the body weights, histopathological scores, malondialdehyde levels and transcription of IL-1b and Tight junction protein 1 (Tjp-1) coding genes, preventive and therapeutic treatment proved to be the most protective in the applied conditions. On the other hand, continuous treatment did not affect the intensity of tissue damage. Considering these results, we discussed the possible mechanisms which might stand behind the protective action of immunostimulating probiotic bacteria in the case of mucosal barrier damage

Contribution to identification of mechanical characteristics of passenger motor vehicle’s drum brakes

Na temelju provedenih analiza, dokazano je da ne postoji opće prihvaćena metoda ocjene karakteristika i izlaznih parametara mehanizama bubanj kočnica. U radu su prikazana eksperimentalna istraživanja podsustava bubanj kočnica s ulaznom vrijednosti-tlakom kočione tekućine u cilindru kočnice i izlaznom vrijednosti-kočnim momentom. Dobiveni rezultati su pokazali da je između izlaza i ulaza postojalo vrijeme kašnjenja, zbog odgovora mehanizma bubanj kočnice. To ukazuje na nedostatak utvrđivanja performansi kočnica u vremenskoj domeni, jer u usporedbi nisu adekvatna uzbuda i odgovor sustava. Stoga se u analizi podsustava bubanj kočnice promatra dinamički mod. Dinamička analiza određuje ponašanje sustava u prijelaznom razdoblju. Uz već poznate prijenosne karakteristike sustava, njegov odgovor može biti određen u odnosu na navedene ulaze, uzbude, što je dobar temelj za određivanje korelacija između rezultata dobivenih različitim metodama identifikacije i pod različitim uvjetima ispitivanja.Based on the conducted analyses, it has been proven that there is no generally accepted method for evaluation of characteristics and output parameters of drum brake mechanisms. Experimental research of the drum brake subsystem with brake fluid pressure in the brake cylinder as input quantity and brake torque as output quantity is presented in the paper. The obtained results show that there is a time delay between the output and input due to the response of the drum brake mechanism. This points to the deficiency of determination of brake performance in time domain, because, in comparison, excitation and response of the system are not adequate. Hence, the dynamic mode is observed in the analysis of the drum brake subsystem. Dynamic analysis determines the behaviour of the system in transient period. With previously known transfer characteristics of a system, its response can be determined in relation to the specified inputs (excitations), which is a good basis for determination of correlation between the results obtained by different methods of identification and under different test conditions

Genotypic and Phenotypic Characterization of Stenotrophomonas maltophilia Strains from a Pediatric Tertiary Care Hospital in Serbia

Background Stenotrophomonas maltophilia is an environmental bacterium and an opportunistic pathogen usually associated with healthcare-associated infections, which has recently been recognized as a globally multi-drug resistant organism. The aim of this study was genotyping and physiological characterization of Stenotrophomonas maltophilia isolated in a large, tertiary care pediatric hospital in Belgrade, Serbia, hosting the national reference cystic fibrosis (CF) center for pediatric and adult patients. Methods We characterized 42 strains of cystic fibrosis (CF) and 46 strains of non-cystic fibrosis (non-CF) origin isolated from 2013 to 2015 in order to investigate their genetic relatedness and phenotypic traits. Genotyping was performed using sequencing of 16S rRNA gene, Pulse Field Gel Electrophoresis (PFGE) and Multi locus sequencing typing (MLST) analysis. Sensitivity to five relevant antimicrobial agents was determined, namely trimethoprim/sulfamethoxazole (TMP/SMX), chloramphenicol, ciprofloxacin, levofloxacin and tetracycline. Surface characteristics, motility, biofilm formation and adhesion to mucin were tested in all strains. Statistical approach was used to determine correlations between obtained results. Results Most of the isolates were not genetically related. Six new sequence types were determined. Strains were uniformly sensitive to all tested antimicrobial agents. The majority of isolates (89.8%) were able to form biofilm with almost equal representation in both CF and non-CF strains. Swimming motility was observed in all strains, while none of them exhibited swarming motility. Among strains able to adhere to mucin, no differences between CF and non-CF isolates were observed. Conclusions High genetic diversity among isolates implies the absence of clonal spread within the hospital. Positive correlation between motility, biofilm formation and adhesion to mucin was demonstrated. Biofilm formation and motility were more pronounced among non-CF than CF isolates

Lactobacillus fermentum Postbiotic-induced Autophagy as Potential Approach for Treatment of Acetaminophen Hepatotoxicity

The aim of this study was to investigate the potential of postbiotics originated from Lactobacillus fermentum BGHV110 strain (HV110) to counteract acetaminophen (APAP)-induced hepatotoxicity in HepG2 cells. This strain was selected according to its autophagy inducing potential, based on previous studies reporting protective role of autophagy in APAP caused cellular damage. Cell viability was assessed using MTT and LDH assays, while autophagy was monitored by qPCR analysis of BECN1, Atg5, p62/SQSTM1, and PINK1 mRNA expression and by Western blot analysis of p62/SQSTM1 and lipidated LC3 accumulation. Our results showed that detrimental effect of APAP on cell viability was suppressed in the presence of HV110 which was linked with increased conversion of LC3 protein and p62/SQSTM1 protein degradation. Additionally, higher p62/SQSTM1 and PINK1 mRNA transcription were noticed in cells co-treated with APAP/HV110, simultaneously. In conclusion, this study suggests that HV110 enhances activation of PINK1-dependent autophagy in HepG2 cells and its eventual co-supplementation with APAP could be potentially used for alleviation of hepatotoxic side effects caused by APAP overdose