Selected models of magnetic hysteresis

Předmětem této práce je studium vybraných modelů feromagnetické hystereze a jejich aplikace na vhodně zvolené magnetické materiály. Byla provedena literární rešerše a byl zpracován přehled modelů feromagnetické hystereze. Podrobněji byl studován Jilesův-Athertonův model a FORC diagramy. Z důvodu existence nesrovnalostí v Jilesově-Athertonově modelu byl navržen nový diferenciální izotropní model feromagnetické hystereze (DIMFH). Pro vysvětlení feromagnetického chování materiálů byl navržen předpoklad existence magnetických klastrů. Tři modifikace Jilesova-Athertonova modelu a model DIMFH byly aplikovány na experimentální data a byly vzájemně porovnány. Byl vytvořen snadno obsluhovatelný kód v prostředí MATLAB pro nalezení parametrů modelů. Byla provedena analýza volně přístupného programového nástroj doFORC, především s ohledem na možná nastavení a jejich vliv na vypočtené FORC diagramy a potlačení šumu.The subject of this thesis is to study selected models of ferromagnetic hysteresis and apply them to properly chosen materials. A literature search was conducted, and an overview of models was compiled. The main focus is on the Jiles-Atherton model and FORC diagrams. Inconsistencies found in the Jiles-Atherton model led to the proposal of a new differential isotropic model of ferromagnetic hysteresis (DIMFH). To describe the ferromagnetic behaviour of materials, the assumption of the existence of magnetic clusters was proposed. Three modifications of Jiles-Atherton model and DIMFH were applied to the experimental data and the models were compared with each other. A user-friendly MATLAB code was created to determine the parameters of the models. An analysis of the freely available doFORC program was performed with an emphasis on possible program settings and noise suppression.480 - Katedra fyzikyvýborn

Determination of saturation magnetostrictive coefficient on the surface of Fe and Co based soft magnetic ribbons

Předmětem bakalářské práce bylo stanovení hodnoty koeficientu magnetostrikce v nasycení magneticky měkkých amorfních pásků na bázi FeSiB a FeCoB. Koeficient byl stanoven Becker-Kerstenovou metodou, kdy byly analyzovány povrchové hysterezní smyčky a magnetické domény při tahovém namáhání, s využitím magnetooptické Kerrovy mikroskopie. Tahová napětí v povrchu vzorků byla modelována pomocí metody konečných prvků a modul pružnosti v tahu byl stanoven tahovou zkouškou. Struktura materiálu a chemické složení byly ověřeny rentgenovou difrakcí a skenovací elektronovou mikroskopií. Hodnoty koeficientů magnetostrikce v nasycení byly korelovány s chemickým složením a strukturou zvolených vzorků.The subject of this bachelor thesis was to determine the saturation magnetostrictive coefficient on the surface of iron and cobalt based magnetically soft amorphous ribbons. The coefficient was determined by the Becker-Kersten method, where surface hysteresis loops and magnetic domains under stress were analyzed, using the magneto-optical Kerr microscopy. The tensile stress in the sample surface was modelled using the finite element method and the Young's modulus was determined by a tensile test. The structure and composition of the samples were evaluated by x-ray diffraction and scanning electron microscopy analysis. Saturation magnetostrictive coefficients were correlated with their structure and composition.480 - Katedra fyzikyvýborn

Efekt koncentrace beta-hydroxybutyrátu v krvi na reprodukci, produkci a zdraví krav v prvních týdnech po otelení

The constant monitoring of dairy cow metabolism is extremely important, especially in the period immediately after calving, when the animals face the consequences of negative energy balance. The concentration of beta-hydroxybutyrate is one of the reliable indicators of metabolic status. The aim of this work was to evaluate the effect of beta-hydroxybutyrate concentration in the blood on selected parameters of production, reproduction, and health of Holstein dairy cows. The limit for subclinical ketosis was set to >1.2 mmol/L of beta-hydroxybutyrate in blood. Furthermore, the effects of lactation number, season, and year of assessment were added to the model equation. The results showed that high betahydroxybutyrate concentration in blood is associated with poor reproduction parameters (worse insemination interval and service period) and lower milk production. However, the results were ambiguous in relation to the somatic cell count and the occurrence of selected diseases (mastitis and ovarian cysts). Moreover, the effect of seasonality on the evaluated parameters was also confirmed (P<0.05), while assessed years were similar in most parameters. It can be concluded that the assessment of beta-hydroxybutyrate concentration as an indicator of potential ketosis is important and can be a suitable parameter for routine monitoring as it influences milk production, reproduction, and cow\u27s health.Sledování úrovně metabolismu u dojnice je neustále důležité a to hlavně v období bezprostředně po otelení, kdy jsou zvířata ohrožena důsledky negativní energetické bilance. Jedním z dobrých ukazatelů úrovně metabolismu je koncentrace beta-hydroxybutyrátu. Cílem této práce bylo zhodnotit vliv koncentrace beta-hydroxybutyrátu v krvi na vybrané parametry produkce, reprodukce a zdraví dojnic holštýnského skotu. Jako hranice subklinické ketózy byla nastavena hodnota beta-hydroxybutyrátu v krvi 1.2 mmol/L. Dele bylo provedeno vyhodnocení s využitím efektů pořadí laktace, kalendářního měsíce a roku hodnocení Z výsledků vyplývá, že je vysoká úroveň beta-hydroxybutyrátu v krvi spojená se zhoršenými parametry plodnosti (horší inseminační interval a servis perioda) a mléčné produkce. Nicméně, ve vztahu k počtu somatických buněk a výskytu vybraných onemocnění (mastitidy a výskyt ovariálních cyst) byly výsledky nejednoznačné. Navíc byl také potvrzen vliv sezónnosti na hodnocené ukazatele (P<0.05) a to i přesto, že hodnocené roky byly ve většině parametrů podobné. Z výsledků lze konstatovat, že hodnocení obsahu beta-hydroxybutyrátu jako indikátoru potenciální ketózy je důležité a potvrzuje se jako vhodný parametr pro rutinní monitoring ovlivňující mléčnou produkci, reprodukci a zdraví krav

Relationship between dairy cows´ physical activity and conception rate

The objective of this study was to create a comprehensive compilation of Czech and foreign scientific literature related to the subject of the thesis. Compilation of literature deal with fertility of cattle and factors which affect fertility. Other chapters discuss Czech Pied cattle, reproduction (anatomy and estrus cycle), estrous and relation between physical activity and conception. Farm researches and subsequent evaluations were part of this bachelor thesis. An information about identification number, date of calving, lactation number, date of insemination, insemination number, period of the highest walking activity, conception, milk yield on the first 100 days of lactation were recorded for each insemination event on 2 farms in Plzeň Region from 2nd November 2015 to 27th December 2015. This data were collected from farm records, herd management softwares and milk recordings. Data on physical activity were obtained from farm management softwares AfiFarm and Westfalia. An information about overall performed 134 inseminations events were collected on farms Zemědělské družstvo Dobříč and Příkosická zemědělská a.s. The data were processed in Microsoft Excel. The aim of research was to evaluate relationship between walking activity, time of insemination and conception rate. The investigated sample of cows was divided into 3 groups according to time of highest walking activity in relation to insemination. Cows of group period 1 had their highest walking activity more than 6 hours before an insemination. Animals with highest walking activity during less than 6 hours before or less than 6 hours after an insemination were put into group period 2. Highest walking activity more than 6 hours after an insemination led to integration of cows into group period 3. The best results were correlated with cows in the group period 1. Animals in the group period 2 rank among second best success rate. The lowest results of conception rate are connected to group period 3. Better reproductive results were found on the farm Zemědělské družstvo Dobříč. Despite comparative difference in obtained reproductive results of each farm the overall average results were comparable with figures of population

Low-density lipoprotein supplementation improves the quality of Holstein bulls' insemination doses

Despite the routine use of cryopreservation in dairy cattle, the subsequent deterioration in the quality of bull insemination doses (IDs) is an incentive to refine cryopreservation protocols, including the composition of the ID. The aim of this study was to examine, using a flow cytometry assay, whether the selected concentrations of low density lipoproteins (LDLs) extracted from hen-egg yolk may improve the post-thaw quality of the ID diluted with a plant-based extender. In total, 30 ejaculates from five sires (six trials per animal) were collected and processed at the Artificial Insemination Centre. The effect of the low density lipoprotein supplementation to the AndroMed® diluent at 4 and 8% (v/v) on the cryopreservation efficiency was tested. The effects of the modified extenders were determined on different sperm subpopulations by simultaneous quadruple staining for flow cytometry as the percentage of sperm with intact plasma membrane and acrosome (PMAI), PMAI sperm showing high mitochondrial membrane potential (HMMP), sperm with plasma membrane damage (PMD), and sperm with acrosome damage (AD). It was observed that the 8% LDL treatment was more effective (P &lt; 0.05) in preserving all the analysed parameters than AndroMed® without any supplementation. The supplementation of the AndroMed® extender with 8% LDL resulted in the most optimal values of the PMAI (30.61 ± 1.13), HMMP (68.81 ± 1.25), PMD (68.69 ± 1.14), and AD (38.36 ± 1.13) compared to the control treatment (24.86 ± 1.13 for PMAI, 47.79 ± 1.25 for HMMP, 74.77 ± 1.14 for PMD, and 42.83 ± 1.13 for AD. The results of the study also demonstrated a synergistic positive effect of the LDL and soybean lecithin-based diluent on the spermatozoa post-thaw quality and resilience, based on 2 h long incubation. In conclusion, the soybean based semen extender treatment with LDL represents a beneficial tool to mitigate the detrimental effect of cryopreservation

The influence of eating and rumination time on solids content in milk and milk yield performance of cows

The aim of this study was to evaluate the effect of rumination time, eating time and season on milk yield and on milk component content in the context of milk recording. The experiment was carried out with two breeds - Czech Fleckvieh cattle and Holstein cattle - for one year. Vitalimetr 5P neck responders were used to monitor eating and rumination time. For statistical evaluation, the time of eating and rumination was divided into three groups according to the length of eating and ruminating, with each breed being categorised separately. The highest protein content, which was 3.6%, was calculated for the group with an average eating time. The fat content was highest for the group with a below-average eating time. On the other hand, the highest milk yield was statistically significantly (P &lt; 0.01) higher in the group with the longest eating time. In terms of rumination, the trend was similar to that of the eating period. In the evaluation of the effect of rumination time, there was no difference in protein %, fat kg and fat % content. A significant (P &lt; 0.05) increase of protein kg was observed with higher rumination time. Changes in milk yield and milk components also occurred throughout the year. During the winter months, the yield decreased, but there was an increase in milk constituent content. During the summer months, the reverse results were obtained. The findings of this study highlight the importance of evaluating eating and rumination time as a potential predictor of milk yield and milk solids content, which are important in milk monetization

Rituximab maintenance significantly reduces early follicular lymphoma progressions in patients treated with frontline R‐CHOP

Abstract Twenty percent of patients with high‐tumor‐burden (HTB) follicular lymphoma (FL) develop progression/relapse of disease (POD) within 24 months of frontline immunochemotherapy. Unfortunately, about 50% of these patients die within 5 years since POD event. Rituximab maintenance was proven to reduce relapse rate in responding FL, but its role on preventing POD was not defined. We analyzed 1360 HTB‐FL patients from the Czech Lymphoma Study Group registry treated with frontline rituximab‐containing regimen. Of those, 950 cases received rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R‐CHOP) and achieved complete or partial remission: 712 patients received rituximab maintenance (MAINT) and 238 were a historical observational cohort (OBS). We have proposed a modified POD24 (mPOD24) endpoint for the chemosensitive patients calculated from the end‐of‐induction (EOI). Survival rates since EOI were as follows: 5‐year overall survival (OS) 86.2% versus 94.5% in the OBS and MAINT groups, respectively (P < .001) and 5‐year progression‐free survival 58.5% (OBS) and 75.4% (MAINT) (P < .001). The Cox proportional hazards model showed a decrease in mPOD24 incidence in the MAINT group with the overall hazard rate reduced by 56% (hazard ratio = 0.44; P < .001). The cumulative incidence of mPOD24 was reduced from 24.1% in OBS to 10.1% in MAINT (P < .001). Comparison of non‐mPOD24 cases showed OS similar to that in the general population. Rituximab maintenance given after R‐CHOP resulted in a 2.4‐fold reduction in mPOD24 incidence. Once the non‐POD24 status is achieved, FL does not shorten the patients’ life expectancy

DataSheet1_Characterization of the input material quality for the production of tisagenlecleucel by multiparameter flow cytometry and its relation to the clinical outcome.pdf

Tisagenlecleucel (tisa-cel) is a CD19-specific CAR-T cell product approved for the treatment of relapsed/refractory (r/r) DLBCL or B-ALL. We have followed a group of patients diagnosed with childhood B-ALL (n = 5), adult B-ALL (n = 2), and DLBCL (n = 25) who were treated with tisa-cel under non-clinical trial conditions. The goal was to determine how the intensive pretreatment of patients affects the produced CAR-T cells, their in vivo expansion, and the outcome of the therapy. Multiparametric flow cytometry was used to analyze the material used for manufacturing CAR-T cells (apheresis), the CAR-T cell product itself, and blood samples obtained at three timepoints after administration. We present the analysis of memory phenotype of CD4/CD8 CAR-T lymphocytes (CD45RA, CD62L, CD27, CD28) and the expression of inhibitory receptors (PD-1, TIGIT). In addition, we show its relation to the patients’ clinical characteristics, such as tumor burden and sensitivity to prior therapies. Patients who responded to therapy had a higher percentage of CD8+CD45RA+CD27+ T cells in the apheresis, although not in the produced CAR-Ts. Patients with primary refractory aggressive B-cell lymphomas had the poorest outcomes which was characterized by undetectable CAR-T cell expansion in vivo. No clear correlation of the outcome with the immunophenotypes of CAR-Ts was observed. Our results suggest that an important parameter predicting therapy efficacy is CAR-Ts’ level of expansion in vivo but not the immunophenotype. After CAR-T cells’ administration, measurements at several timepoints accurately detect their proliferation intensity in vivo. The outcome of CAR-T cell therapy largely depends on biological characteristics of the tumors rather than on the immunophenotype of produced CAR-Ts.</p