44 research outputs found

    Industry 4.0 and its impact on employment

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    Tato bakalářská práce zpracovává téma Průmyslu 4.0 a zkoumá, jaký má vliv na zaměstnanost v konkrétním podniku. V teoretické části jsou vymezeny základní pojmy týkající se Průmyslu 4.0, popsány průmyslové revoluce a popsány dopady konceptu Průmyslu 4.0 na společnost a trh práce. V praktické části proběhla podrobná analýza podniku, jeho produktu a výrobních procesů. Následně je za pomoci polostrukturovaného dotazníku s odborníkem z vedení společnosti zjištěno, jak společnost Průmysl 4.0 vnímá, jaké kroky zavedla, jakým směrem se chce v budoucnosti orientovat a jaký má Průmysl 4.0 vliv na zaměstnanost. Na závěr jsou zodpovězeny výzkumné otázky a vyhodnoceno splnění cíle této bakalářské práce.ObhájenoThis bachelor thesis deals with the topic of Industry 4.0 and examines how it affects employment in a particular company. The theoretical part defines the basic concepts related to Industry 4.0, describes the industrial revolutions, and describes the impacts of the concept of Industry 4.0 on society and the labor market. In the practical part there was a detailed analysis of the company, its product and production processes. Subsequently, with the help of a semi-structured questionnaire with an expert from the company's management, it is found out how Industry 4.0 perceives, what steps it has taken, what direction it wants to take in the future and how Industry 4.0 has an impact on employment. Finally, the research questions are answered and the fulfillment of the goal of the bachelor thesis is evaluated

    Mass Spectrometric Characterization of Oligomers in Pseudomonas aeruginosa Azurin Solutions

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    We have employed laser-induced liquid bead ion desorption mass spectroscopy (LILBID MS) to study the solution behavior of Pseudomonas aeruginosa azurin as well as two mutants and corresponding Re-labeled derivatives containing a Re(CO)_(3)(4,7-dimethyl-1,10-phenanthroline)^+ chromophore appended to a surface histidine. LILBID spectra show broad oligomer distributions whose particular patterns depend on the solution composition (pure H_(2)O, 20−30 mM NaCl, 20 and 50 mM NaP_i or NH_(4)P_i at pH = 7). The distribution maximum shifts to smaller oligomers upon decreasing the azurin concentration and increasing the buffer concentration. Oligomerization is less extensive for native azurin than its mutants. The oligomerization propensities of unlabeled and Re-labeled proteins are generally comparable, and only Re126 shows some preference for the dimer that persists even in highly diluted solutions. Peak shifts to higher masses and broadening in 20−50 mM NaP_i confirm strong azurin association with buffer ions and solvation. We have found that LILBID MS reveals the solution behavior of weakly bound nonspecific protein oligomers, clearly distinguishing individual components of the oligomer distribution. Independently, average data on oligomerization and the dependence on solution composition were obtained by time-resolved anisotropy of the Re-label photoluminescence that confirmed relatively long rotation correlation times, 6−30 ns, depending on Re−azurin and solution composition. Labeling proteins with Re-chromophores that have long-lived phosphorescence extends the time scale of anisotropy measurements to hundreds of nanoseconds, thereby opening the way for investigations of large oligomers with long rotation times

    Electronic Structures of Reduced and Superreduced Ir_2(1,8-diisocyanomenthane)_4^(n+) Complexes

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    Molecular and electronic structures of Ir_2(1,8-diisocyanomenthane)_4^(n+) (Ir(dimen)^(n+)) complexes have been investigated by DFT for n = 2, 1, 0 (abbreviated 2+, 1+, 0). Calculations reproduced the experimental structure of 2+, ν(C≡N) IR, and visible absorption spectra of all three oxidation states, as well as the EPR spectrum of 1+. We have shown that the two reduction steps correspond to successive filling of the Ir–Ir pσ orbital. Complexes 2+ and 1+ have very similar structures with 1+ having a shorter Ir–Ir distance. The unpaired electron density in 1+ is delocalized along the Ir–Ir axis and over N atoms of the eight C≡N– ligands. The second reduction step 1+ → 0 changes the Ir(CN−)_4 coordination geometry at each Ir site from approximately planar to seesaw whereby one −N≡C–Ir–C≡N– moiety is linear and the other bent at the Ir (137°) as well as N (146°) atoms. Although complex 0 is another example of a rare (pσ)2 dimetallic species (after [Pt_2(μ-P_2O_5(BF_2)_2)_4]^(6–), J. Am. Chem. Soc. 2016, 138, 5699), the redistribution of lower lying occupied molecular orbitals increases electron density predominantly at the bent C≡N– ligands whose N atoms are predicted to be nucleophilic reaction centers

    Potential effect of wetting agents added to agricultural sprays on the stability of soil aggregates

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    A potential effect of adjuvants/wetting agents added to the spray mixture on the water stability of soil aggregates (WSA) in agricultural soil was studied. Nine sites were chosen in the Czech Republic. Each site was mapped using representative soil pits (depth min. 1.3 m). A total of 54 mixed samples were collected from topsoil horizons on the selected sites. The samples were exposed to the action of four different types of wetting agents (organosilicone wetting agent; methyl ester of rapeseed oil; mixture of methyl ester palmitic and oleic acids; isodecyl alcohol ethoxylate), which are the most common wetting agents used in agriculture in the Czech Republic. WSA was determined before and after the addition of wetting agents (WA). Initial WSA values were at the same level in a majority of sampling points. Two sites were an exception, on which Haplic Luvisols and Relictistagnic Fluvisols occurred. These soil types featured the lowest WSA values. After the addition of WA across the sampling points, average WSA values exhibited a demonstrable trend: WSA of control sample (without the WA application) was at all times higher than in samples with the addition of WA. If the measured WSA values are compared in terms of overall means, it is evident that the control variant always exhibited the highest WSA value (on average 44.04 %) and the variants with the application of WA showed always WSA values lower by min 16 %. The worst effect on WSA was that of wetting agents whose basic component was methyl ester of rapeseed. These wetting agents caused a decrease in WSA by more than 50 %. All soil samples were also analysed for basic soil parameters (glomalin, oxidizable carbon - C-ox, pH, Na, P, Ca, K, Mg) in order to determine their potential influence on aggregate stability and to possibly eliminate the negative impact of WA. In this respect, only a significant influence of C-ox content on WSA was recorded, which positively correlated with the stability of soil aggregates.O

    Charge Photoinjection in Intercalated and Covalently Bound [Re(CO)_(3)(dppz)(py)]^(+)–DNA Constructs Monitored by Time-Resolved Visible and Infrared Spectroscopy

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    The complex [Re(CO)_(3)(dppz)(py′-OR)]+ (dppz = dipyrido[3,2-a:2′,3′-c]phenazine; py′-OR = 4-functionalized pyridine) offers IR sensitivity and can oxidize DNA directly from the excited state, making it a promising probe for the study of DNA-mediated charge transport (CT). The behavior of several covalent and noncovalent Re–DNA constructs was monitored by time-resolved IR (TRIR) and UV/visible spectroscopies, as well as biochemical methods, confirming the long-range oxidation of DNA by the excited complex. Optical excitation of the complex leads to population of MLCT and at least two distinct intraligand states. Experimental observations that are consistent with charge injection from these excited states include similarity between long-time TRIR spectra and the reduced state spectrum observed by spectroelectrochemistry, the appearance of a guanine radical signal in TRIR spectra, and the eventual formation of permanent guanine oxidation products. The majority of reactivity occurs on the ultrafast time scale, although processes dependent on slower conformational motions of DNA, such as the accumulation of oxidative damage at guanine, are also observed. The ability to measure events on such disparate time scales, its superior selectivity in comparison to other spectroscopic techniques, and the ability to simultaneously monitor carbonyl ligand and DNA IR absorption bands make TRIR a valuable tool for the study of CT in DNA

    Thermally Tunable Dual Emission of the d^8–d^8 Dimer [Pt_2(μ-P_2O_5(BF_2)_2)_4]^(4–)

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    High-resolution fluorescence, phosphorescence, as well as related excitation spectra, and, in particular, the emission decay behavior of solid [Bu_4N]_4[Pt_2(μ-P_2O_5(BF_2)_2)_4], abbreviated Pt(pop-BF_2), have been investigated over a wide temperature range, 1.3–310 K. We focus on the lowest excited states that result from dσ^*pσ (5d_z2–6p_z) excitations, i.e., the singlet state S_1 (of ^1A_2u symmetry in D_(4h)) and the lowest triplet T_1, which splits into spin–orbit substates A_(1u)(^3A_(2u)) and E_u(^3A_(2u)). After optical excitation, an unusually slow intersystem crossing (ISC) is observed. As a consequence, the compound shows efficient dual emission, consisting of blue fluorescence and green phosphorescence with an overall emission quantum yield of ∼100% over the investigated temperature range. Our investigation sheds light on this extraordinary dual emission behavior, which is unique for a heavy-atom transition metal compound. Direct ISC processes in Pt(pop-BF_2) are largely forbidden due to spin-, symmetry-, and Franck–Condon overlap-restrictions and, therefore, the ISC time is as long as 29 ns for T < 100 K. With temperature increase, two different thermally activated pathways, albeit still relatively slow, are promoted by spin-vibronic and vibronic mechanisms, respectively. Thus, distinct temperature dependence of the ISC processes results and, as a consequence, also of the fluorescence/phosphorescence intensity ratio. The phosphorescence lifetime also is temperature-dependent, reflecting the relative population of the triplet T_1 substates E_u and A_(1u). The highly resolved phosphorescence shows a ∼220 cm^(–1) red shift below 10 K, attributable to zero-field splitting of 40 cm^(–1) plus a promoting vibration of 180 cm^(–1)

    Electron hopping through proteins

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    Biological redox machines require efficient transfer of electrons and holes for function. Reactions involving multiple tunneling steps, termed “hopping,” often promote charge separation within and between proteins that is essential for energy storage and conversion. Here we show how semiclassical electron transfer theory can be extended to include hopping reactions: graphical representations (called hopping maps) of the dependence of calculated two-step reaction rate constants on driving force are employed to account for flow in a rhenium-labeled azurin mutant as well as in two structurally characterized redox enzymes, DNA photolyase and MauG. Analysis of the 35 Å radical propagation in ribonucleotide reductases using hopping maps shows that all tyrosines and tryptophans on the radical pathway likely are involved in function. We suggest that hopping maps can facilitate the design and construction of artificial photosynthetic systems for the production of fuels and other chemicals

    Electronic Structures of Reduced and Superreduced Ir_2(1,8-diisocyanomenthane)_4^(n+) Complexes

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    Molecular and electronic structures of Ir_2(1,8-diisocyanomenthane)_4^(n+) (Ir(dimen)^(n+)) complexes have been investigated by DFT for n = 2, 1, 0 (abbreviated 2+, 1+, 0). Calculations reproduced the experimental structure of 2+, ν(C≡N) IR, and visible absorption spectra of all three oxidation states, as well as the EPR spectrum of 1+. We have shown that the two reduction steps correspond to successive filling of the Ir–Ir pσ orbital. Complexes 2+ and 1+ have very similar structures with 1+ having a shorter Ir–Ir distance. The unpaired electron density in 1+ is delocalized along the Ir–Ir axis and over N atoms of the eight C≡N– ligands. The second reduction step 1+ → 0 changes the Ir(CN−)_4 coordination geometry at each Ir site from approximately planar to seesaw whereby one −N≡C–Ir–C≡N– moiety is linear and the other bent at the Ir (137°) as well as N (146°) atoms. Although complex 0 is another example of a rare (pσ)2 dimetallic species (after [Pt_2(μ-P_2O_5(BF_2)_2)_4]^(6–), J. Am. Chem. Soc. 2016, 138, 5699), the redistribution of lower lying occupied molecular orbitals increases electron density predominantly at the bent C≡N– ligands whose N atoms are predicted to be nucleophilic reaction centers

    Ultrafast Wiggling and Jiggling: Ir_2(1,8-diisocyanomenthane)_4^(2+)

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    Binuclear complexes of d^8 metals (Pt^(II), Ir^I, Rh^I,) exhibit diverse photonic behavior, including dual emission from relatively long-lived singlet and triplet excited states, as well as photochemical energy, electron, and atom transfer. Time-resolved optical spectroscopic and X-ray studies have revealed the behavior of the dimetallic core, confirming that M–M bonding is strengthened upon dσ* → pσ excitation. We report the bridging ligand dynamics of Ir2(1,8-diisocyanomenthane)_4^(2+)(Ir(dimen)), investigated by fs–ns time-resolved IR spectroscopy (TRIR) in the region of C≡N stretching vibrations, ν(C≡N), 2000–2300 cm^(–1). The ν(C≡N) IR band of the singlet and triplet dσ*pσ excited states is shifted by −22 and −16 cm^(–1) relative to the ground state due to delocalization of the pσ LUMO over the bridging ligands. Ultrafast relaxation dynamics of the ^1dσ*pσ state depend on the initially excited Franck–Condon molecular geometry, whereby the same relaxed singlet excited state is populated by two different pathways depending on the starting point at the excited-state potential energy surface. Exciting the long/eclipsed isomer triggers two-stage structural relaxation: 0.5 ps large-scale Ir–Ir contraction and 5 ps Ir–Ir contraction/intramolecular rotation. Exciting the short/twisted isomer induces a ∼5 ps bond shortening combined with vibrational cooling. Intersystem crossing (70 ps) follows, populating a ^3dσ*pσ state that lives for hundreds of nanoseconds. During the first 2 ps, the ν(C≡N) IR bandwidth oscillates with the frequency of the ν(Ir–Ir) wave packet, ca. 80 cm^(–1), indicating that the dephasing time of the high-frequency (16 fs)^(−1) C≡N stretch responds to much slower (∼400 fs)^(−1)Ir–Ir coherent oscillations. We conclude that the bonding and dynamics of bridging di-isocyanide ligands are coupled to the dynamics of the metal–metal unit and that the coherent Ir–Ir motion induced by ultrafast excitation drives vibrational dephasing processes over the entire binuclear cation

    Ultrafast Excited-State Dynamics of Rhenium(I) Photosensitizers [Re(Cl)(CO)_(3)(N,N)] and [Re(imidazole)(CO)_(3)(N,N)]^+: Diimine Effects

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    Femto- to picosecond excited-state dynamics of the complexes [Re(L)(CO)_(3)(N,N)]^n (N,N = bpy, phen, 4,7-dimethyl-phen (dmp); L = Cl, n = 0; L = imidazole, n = 1+) were investigated using fluorescence up-conversion, transient absorption in the 650−285 nm range (using broad-band UV probe pulses around 300 nm) and picosecond time-resolved IR (TRIR) spectroscopy in the region of CO stretching vibrations. Optically populated singlet charge-transfer (CT) state(s) undergo femtosecond intersystem crossing to at least two hot triplet states with a rate that is faster in Cl (~100 fs)^(−1) than in imidazole (~150 fs)^(−1) complexes but essentially independent of the N,N ligand. TRIR spectra indicate the presence of two long-lived triplet states that are populated simultaneously and equilibrate in a few picoseconds. The minor state accounts for less than 20% of the relaxed excited population. UV−vis transient spectra were assigned using open-shell time-dependent density functional theory calculations on the lowest triplet CT state. Visible excited-state absorption originates mostly from mixed L;N,N^(•−) → Re^(II) ligand-to-metal CT transitions. Excited bpy complexes show the characteristic sharp near-UV band (Cl, 373 nm; imH, 365 nm) due to two predominantly ππ*(bpy^(•−)) transitions. For phen and dmp, the UV excited-state absorption occurs at 305 nm, originating from a series of mixed ππ* and Re → CO;N,N•− MLCT transitions. UV−vis transient absorption features exhibit small intensity- and band-shape changes occurring with several lifetimes in the 1−5 ps range, while TRIR bands show small intensity changes (≤5 ps) and shifts (~1 and 6−10 ps) to higher wavenumbers. These spectral changes are attributable to convoluted electronic and vibrational relaxation steps and equilibration between the two lowest triplets. Still slower changes (≥15 ps), manifested mostly by the excited-state UV band, probably involve local-solvent restructuring. Implications of the observed excited-state behavior for the development and use of Re-based sensitizers and probes are discussed
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