Individual Professional Practice in the Company

Import 23/08/2017Cílem této bakalářské práce je popsat absolvování odborné praxe ve firmě HS Interactive s.r.o. Praxe byla zaměřena na vývoj mobilní aplikace pro operační systém Android. Aplikace je mobilním klientem pro sociální síť MatchToMe. V úvodu popisuji důvody, které vedly k výběru odborné praxe. Dále se věnuji úkolům, které mi byly zadány s jejich implementací a postupem řešení problémů, které se objevily při vývoji. Závěr práce je věnován zhodnocení získaných zkušeností a dosažených výsledků.Purpose of this bachelor thesis is to describe a professional practice in company HS Interactive s.r.o. Practice was focused on the development of mobile application for the operating system Android. The application is a mobile client for social network MatchToMe. In the introduction I describe reasons that led to the selection of professional practice. Then I describe tasks that I have been awarded with their implementations and process of solution issues that have emerged during development. The conclusion of thesis is dedicated to the evaluation of the experience gained and the results achieved.440 - Katedra telekomunikační technikyvýborn

Copper-Catalyzed Aerobic Oxidative Reaction of C₆₀ with Aliphatic Primary Amines and CS₂

A novel type of fullerene derivatives, [60]­fullerothiazolidinethiones (<b>2</b>), were obtained from the copper-catalyzed aerobic oxidative reaction of C₆₀ with aliphatic primary amines and CS₂ in 4:1 <i>v</i>/<i>v</i> DMF and <i>o</i>-DCB. The obtained products were fully characterized with the X-ray single-crystal diffraction and spectroscopic methods. Control experiment with maleic anhydride, an analogue to C₆₀, also afforded thiazolidinethione product, but via a mechanism different from that of C₆₀ judging from the structure difference between the two types of thiazolidinethione compounds, demonstrating the unique reactivity of C₆₀

Aerobic Oxidations of C₆₀^2– in the Presence of PhCN and PhCH₂CN: Oxygenation versus Dehydrogenation Reactions

Aerobic oxidations of dianionic C₆₀ were examined in PhCN and PhCH₂CN, where dioxygen was activated to O₂^•– via the single-electron transfer from C₆₀^2– and underwent oxygenation and dehydrogenation reactions, respectively. Addition of PhCH₂Br led to further benzylation for the oxygenated product but not for the dehydrogenated one, suggesting that the initial two negative charges were preserved for the intermediates of the oxygenation reaction but not for those of the dehydrogenation reaction

Surface Energy-Mediated Multistep Pathways for Heterogeneous Ice Nucleation

Heterogeneous ice nucleation (HIN) is the dominant mode of ice formation, while its kinetic pathways remain poorly understood. The classical nucleation theory suggests a one-step pathway, that is, direct change from liquid water to ice (e.g. hexagonal ice), which has been widely accepted. In this work, however, through molecular dynamics simulations, we observe an intermediate state, square ice, at the early stage of ice nucleation at certain surface energies. The intermediate square ice gives rise to a new nonclassical pathway for HIN: from liquid water to hexagonal ice via square ice. This multistep pathway may coexist with and can be more probable than the classical one-step pathway though it may delay the ice nucleation process. The new multistep pathway offers insights in controlling the kinetics of ice crystallization and understating the mechanisms of HIN

Roles of Surface Energy and Temperature in Heterogeneous Ice Nucleation

Heterogeneous ice nucleation (HIN) is strongly related to the dynamics of hydrogen bonds in water at an interface. In this work, we investigate the microscopic kinetics of HIN through molecular dynamics simulations. The dynamics of hydrogen bond network (HBN) at interfaces is studied under the coupled effects of thermal fluctuation and water–surface molecular interactions. It is revealed that the lasting time of the HBN at the interface is critical to HIN. Under comparable thermal and surface effects, which result in a proper lasting time of the HBN, HIN is promoted. However, if the thermal effect or the surface effect dominates over the other, the lasting time of the HBN at the interface would be either too long or too short, leading to the failure of HIN. By varying the water–surface interaction strength, i.e., binding energy, and temperature, a diagram of HIN events is presented, which shows that HIN is only favored in certain temperature and surface energy ranges

Base-Promoted Oxidative Cycloaddition Reaction of [60]Fullerene with Ethyl Acetoacetate for C₆₀ Bis-2′,3′-dihydrofuran Derivatives: Effect of Bulky Addends

The base-promoted oxidative cycloaddition reaction of [60]­fullerene with ethyl acetoacetate was investigated. The reaction resulted in C₆₀ bis-2′,3′-dihydrofuran derivatives, but only with the <i>trans</i>-1, <i>trans</i>-2, <i>trans</i>-3, and <i>e</i> configurations rather than any <i>cis</i> or <i>trans</i>-4 structures, demonstrating a new regioselectivity resulting from steric influence on C₆₀ bisaddition. In addition, distribution of the bisadducts was complicated by the unsymmetrical nature of the addends, where each individual configuration may consist of several regioisomers

Higher serum choline and betaine levels are associated with better body composition in male but not female population

<div><p>Background</p><p>Animal studies proved that choline and betaine have beneficial effect on reducing body fat. However, evidence in humans is scarce. We aim to investigate the association between serum choline and betaine levels with body composition in general population.</p><p>Methods</p><p>This is an observational cross-sectional study performed in 1081 subjects from the CODING (Complex Disease in Newfoundland population: Environment and Genetics) study. Serum choline and betaine levels were measured based on liquid chromatography coupled with tandem mass spectrometry technology. Body composition was measured using dual-energy X-ray absorptiometry following a 12-hour fast. Major confounding factors including age, sex, total calorie intake and physical activity level were controlled in all analyses.</p><p>Results</p><p>Significantly inverse correlations were found between serum betaine levels and all obesity measurements in males (r ranged from -0.12 to -0.23, and p<0.01 for all) but not in females. Serum choline was negatively associated with total percent body fat (¿), percent trunk fat (%TF), weight, body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (r ranged from -0.11 to -0.19, and p<0.05 for all) in males and positively associated with weight, BMI and WC (r ranged from 0.09 to 0.10, and p<0.05 for all) in females. The negative associations between serum choline and betaine levels with obesity in males were more profound in those not on any medication than those taking medications. Moreover, obese males had the lowest serum choline and betaine levels, followed by overweight males, and normal weight males having the highest serum choline and betaine levels, especially in those not taking medications (p<0.05). Likewise, subjects with the highest serum levels of both had the lowest obesity indexes, especially those not taking medications.</p><p>Conclusions</p><p>Higher serum choline and betaine levels were associated with a more favorable body composition (lower body fat and higher lean body mass) in males and the favorable association was more pronounced in non-medication users.</p></div

Metabolic Engineering of <i>Candida glabrata</i> for Diacetyl Production

<div><p>In this study, <i>Candida glabrata</i>, an efficient pyruvate-producing strain, was metabolically engineered for the production of the food ingredient diacetyl. A diacetyl biosynthetic pathway was reconstructed based on genetic modifications and medium optimization. The former included (i) channeling carbon flux into the diacetyl biosynthetic pathway by amplification of acetolactate synthase, (ii) elimination of the branched pathway of α-acetolactate by deleting the <i>ILV5</i> gene, and (iii) restriction of diacetyl degradation by deleting the <i>BDH</i> gene. The resultant strain showed an almost 1∶1 co-production of α-acetolactate and diacetyl (0.95 g L⁻¹). Furthermore, addition of Fe³⁺ to the medium enhanced the conversion of α-acetolactate to diacetyl and resulted in a two-fold increase in diacetyl production (2.1 g L⁻¹). In addition, increased carbon flux was further channeled into diacetyl biosynthetic pathway and a titer of 4.7 g L⁻¹ of diacetyl was achieved by altering the vitamin level in the flask culture. Thus, this study illustrates that <i>C. glabrata</i> could be tailored as an attractive platform for enhanced biosynthesis of beneficial products from pyruvate by metabolic engineering strategies.</p></div

Methoxylation of Singly Bonded 1,4–1′,4′-BnC₆₀–C₆₀Bn Dimer: Preferential Formation of 1,4‑C₆₀ Adduct with Sterically Less Demanding Addends and Stability Difference between 1,2- and 1,4-OMe(Bn)C₆₀

Methoxylation of the singly bonded 1,4–1′,4′-BnC₆₀–C₆₀Bn dimer afforded 1,4-OMe­(Bn)­C₆₀, a 1,4-C₆₀ adduct with sterically less demanding addends, as the major adduct. The situation was different from that of direct functionalization of C₆₀, where 1,2-OMe­(Bn)­C₆₀ was obtained as the major product. The reaction was studied with in situ vis-NIR spectroscopy and computational calculations to obtain a better understanding of this unusual regioselectivity. The stability difference between 1,2- and 1,4-OMe­(Bn)­C₆₀ was studied

Potassium-induced plant resistance against soybean cyst nematode via root exudation of phenolic acids and plant pathogen-related genes

<div><p>Soybean cyst nematode (SCN) is a severe soil borne disease. The control of this disease is still a worldwide problem in agriculture. In this study, we found that application of potassium (K) fertilizer could decrease the occurrence of SCN at two field sites. Furthermore, the application of K could suppress <i>Heterodera glycines</i> with the activation of Phenylalanine Ammonia Lyase (<i>PAL)</i> and Polyphenol Oxidase (<i>PPO)</i> expression via pot experiments in a greenhouse. The release of cinnamic, ferulic and salicylic acids was significantly enhanced by K application of 3 mM, and each of three acids can dramatically constrain <i>Heterodera glycines</i> in vitro. This research indicated that K induce multiple mechanisms to improve the resistance of soybean against SCN and provide a new strategy to control SCN in fields with nutrient application.</p></div