Energy decomposition analysis Dotaz Zobrazit nápovědu
Plant litter is the major source of energy and nutrients in stream ecosystems and its decomposition is vital for ecosystem nutrient cycling and functioning. Invertebrates are key contributors to instream litter decomposition, yet quantification of their effects and drivers at the global scale remains lacking. Here, we systematically synthesized data comprising 2707 observations from 141 studies of stream litter decomposition to assess the contribution and drivers of invertebrates to the decomposition process across the globe. We found that (1) the presence of invertebrates enhanced instream litter decomposition globally by an average of 74%; (2) initial litter quality and stream water physicochemical properties were equal drivers of invertebrate effects on litter decomposition, while invertebrate effects on litter decomposition were not affected by climatic region, mesh size of coarse-mesh bags or mycorrhizal association of plants providing leaf litter; and (3) the contribution of invertebrates to litter decomposition was greatest during the early stages of litter mass loss (0-20%). Our results, besides quantitatively synthesizing the global pattern of invertebrate contribution to instream litter decomposition, highlight the most significant effects of invertebrates on litter decomposition at early rather than middle or late decomposition stages, providing support for the inclusion of invertebrates in global dynamic models of litter decomposition in streams to explore mechanisms and impacts of terrestrial, aquatic, and atmospheric carbon fluxes.
- Klíčová slova
- climatic region, decomposition rate, decomposition stage, litterbag, mass loss, meta-analysis,
- MeSH
- bezobratlí MeSH
- biodegradace MeSH
- ekosystém * MeSH
- listy rostlin MeSH
- řeky * MeSH
- rostliny MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Samples of 2,4,6-trinitrotoluene (TNT) exposed to heat or to shock and residues after their detonation have been analyzed chromatographically (LC-UV and LC/MS). It was found that the main identified decomposition intermediates are identical in all the three cases. 4,6-Dinitro-2,1-benzoisoxazole and 2,4,6-trinitrobenzaldehyde are the most reactive from them. It has been stated that the chemical micro-mechanism of the primary fragmentations of shock-exposed TNT molecules and/or its detonation transformation should be the same as in the case of its low-temperature thermal decomposition.
- MeSH
- chromatografie kapalinová MeSH
- diferenční termická analýza MeSH
- hmotnostní spektrometrie MeSH
- rázové vlny s vysokou energií MeSH
- spektrofotometrie ultrafialová MeSH
- trinitrotoluen chemie MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- trinitrotoluen MeSH
Decomposition of cisplatin in an aqueous 0.15 M chloride solution by diffuse daylight, by monochromatic light, and by ultrasonic energy was studied using a new HPLC method. The relative sensitivity of cisplatin to light copies the curve of the absorption spectrum of cisplatin with maximum at ca. 300 nm; however, any light below 500 nm must be avoided. Sonication also leads to a rapid decomposition of cisplatin. Irradiation by diffuse daylight or sonication of the cisplatin solutions for 5 min leads to ca. 1% amminetrichloroplatinate(II). Using HPLC analysis with diode-array spectrophotometric detection, the main decomposition product was identified as amminetrichloroplatinate(II).
- MeSH
- antitumorózní látky chemie MeSH
- chloridy farmakologie MeSH
- cisplatina chemie účinky záření MeSH
- roztoky MeSH
- stabilita léku MeSH
- světlo MeSH
- ultrazvuk MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- antitumorózní látky MeSH
- chloridy MeSH
- cisplatina MeSH
- roztoky MeSH
Interaction energies computed with density functional theory can be divided into physically meaningful components by symmetry-adapted perturbation theory (DFT-SAPT) or the canonical energy decomposition analysis (EDA). In this work, the decomposition results obtained by these schemes were compared for more than 200 hydrogen-, halogen-, and pnicogen-bonded, dispersion-bound, and mixed complexes to investigate their similarity in the evaluation of the nature of noncovalent interactions. BLYP functional with D3(BJ) correction was used for the EDA scheme, whereas asymptotically corrected PBE0 functional for DFT-SAPT provided some of the best combinations for description of noncovalent interactions. Both schemes provide similar results concerning total interaction energies and insight into the individual energy components. For most complexes, the dominant energetic term was identified equally by both decomposition schemes. Because the canonical EDA is computationally less demanding than the DFT-SAPT, the former can be especially used in cases where the systems investigated are very large.
- Publikační typ
- časopisecké články MeSH
The study aims to analyze and decompose the qualitative parameters of wood chips in Poland. The European Green Deal brings the new framework to support sustainability and elimination of emissions. The Wavelet coherence and Wavelet Discrete Decomposition are used for determination of relations among significant qualitative parameters. Thus, the possible uses are discussed. For the obvious relationship between moisture and calorific value there is evidence of strong correlation. The behaviour of these interrelations are different at frequencies in the long and short time. The wood chip price is inter-transmitter from moisture parameter to calorific value in a positive (in-phase) relationship. At both low and high frequencies there is evidence that the variables of moisture and calorific value are highly correlated. The transient effect of linkage is presented at values between 0.1 and 0.3 in coherence map. The empirical findings provide implication for local producers and policymakers.
- Klíčová slova
- Calorific value, Moisture content, Power plant, Wavelet coherence, Wavelet transform, Wood chip price, Wood chips,
- Publikační typ
- časopisecké články MeSH
A series of new VO(IV) complexes of tetradentate N2O2 Schiff base ligands (L(1)-L(4)), were synthesized and characterized by FT-IR, UV-vis and elemental analysis. The structure of the complex VOL(1)⋅DMF was also investigated by X-ray crystallography which revealed a vanadyl center with distorted octahedral coordination where the 2-aza and 2-oxo coordinating sites of the ligand were perpendicular to the "-yl" oxygen. The electrochemical properties of the vanadyl complexes were investigated by cyclic voltammetry. A good correlation was observed between the oxidation potentials and the electron withdrawing character of the substituents on the Schiff base ligands, showing the following trend: MeO
- Klíčová slova
- Electrochemistry, Kinetics of thermal decomposition, Oxovanadium(IV) complexes, Schiff base,
- MeSH
- elektrochemie MeSH
- kinetika MeSH
- krystalografie rentgenová MeSH
- molekulární modely MeSH
- Schiffovy báze chemie MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- termodynamika MeSH
- vanadáty chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- oxovanadium IV MeSH Prohlížeč
- Schiffovy báze MeSH
- vanadáty MeSH
This work studies the underlying nature of H-bonds (HBs) of different types and strengths and tries to predict binding energies (BEs) based on the properties derived from wave function analysis. A total of 42 HB complexes constructed from 28 neutral and 14 charged monomers were considered. This set was designed to sample a wide range of HB strengths to obtain a complete view about HBs. BEs were derived with the accurate coupled cluster singles and doubles with perturbative triples correction (CCSD(T))(T) method and the physical components of the BE were investigated by symmetry-adapted perturbation theory (SAPT). Quantum theory of atoms-in-molecules (QTAIM) descriptors and other HB indices were calculated based on high-quality density functional theory wave functions. We propose a new and rigorous classification of H-bonds (HBs) based on the SAPT decomposition. Neutral complexes are either classified as "very weak" HBs with a BE ≥ -2.5 kcal/mol that are mainly dominated by both dispersion and electrostatic interactions or as "weak-to-medium" HBs with a BE varying between -2.5 and -14.0 kcal/mol that are only dominated by electrostatic interactions. On the other hand, charged complexes are divided into "medium" HBs with a BE in the range of -11.0 to -15.0 kcal/mol, which are mainly dominated by electrostatic interactions, or into "strong" HBs whose BE is more negative than -15.0 kcal/mol, which are mainly dominated by electrostatic together with induction interactions. Among various explored correlations between BEs and wave function-based HB descriptors, a fairly satisfactory correlation was found for the electron density at the bond critical point (BCP; ρBCP ) of HBs. The fitted equation for neutral complexes is BE/kcal/mol = - 223.08 × ρBCP /a. u. + 0.7423 with a mean absolute percentage error (MAPE) of 14.7%, while that for charged complexes is BE/kcal/mol = - 332.34 × ρBCP /a. u. - 1.0661 with a MAPE of 10.0%. In practice, these equations may be used for a quick estimation of HB BEs, for example, for intramolecular HBs or large HB networks in biomolecules. © 2019 Wiley Periodicals, Inc.
We present a general, flexible framework for a constant-energy variant of the dissipative particle dynamics method that allows chemical reactions (DPD-RX). In our DPD-RX approach, reaction progress variables are assigned to each particle that monitor the time evolution of an extent-of-reaction associated with the prescribed reaction mechanisms and kinetics assumed to occur within the particle, where chemistry can be modeled using complex or reduced reaction mechanisms. We demonstrate our DPD-RX method by considering thermally initiated unimolecular decomposition of the energetic material, cyclotrimethylene trinitramine (RDX), into a molecular gas mixture. Studies are performed to demonstrate the effect of a spatially averaged particle internal temperature and a local reaction volume term in the chemical kinetics expressions, where both provide implicit mechanisms for capturing condensed phase reactivity. We also present an analysis of the expansion of the product gas mixture during decomposition. Finally, a discussion of other potential applications and extensions of the DPD-RX method is given.
- Publikační typ
- časopisecké články MeSH
BACKGROUND/AIM: The aim of this study was to evaluate the possibility to discriminate the blood clot from tumorous tissue in the assessment of transitional cell carcinoma (TCC), when CT data are used only from single-phase dual-energy CT (DECT). MATERIALS AND METHODS: A total of 18 patients were included into the retrospective analysis of the prospectively collected data (the average age was 67.3 years, range=62-79 years, 12 males, 6 females). DECT was performed in all patients after intravenous administration of the iodinated contrast material. DECT analysis using three-material decomposition algorithm was used to discriminate blood and enhancing tumorous tissue. In all patients, TCC was detected and subsequently kidney surgery or endoscopy was performed within the next two weeks. The findings were compared with DECT results. RESULTS: In our cohort of patients we found 9 TCC of the renal pelvis or ureter and 7 TCC of the urinary bladder. The accuracy of the TCC detection was 94% (17/18). The presence of coagulated blood within the urinary collecting system together with a tumor was detected in 7 CT examinations. The blood coagulum without a confirmed malignant tumor was found in one case with false positive DECT finding. In other 6 cases bleeding was confirmed during surgery or endoscopy (accuracy 87%). CONCLUSION: The dual-energy data analysis enables discrimination of a blood clot from tumorous tissue. It helps in detection of UCC in cases when the excretion potential of the kidneys is decreased due to fulfillment of the collecting system with blood clots.
- Klíčová slova
- Dual-energy CT, hematuria, transient cell carcinoma, urinary tract tumors,
- MeSH
- algoritmy MeSH
- jod analýza MeSH
- karcinom z přechodných buněk diagnóza diagnostické zobrazování patologie MeSH
- kontrastní látky MeSH
- ledviny patologie chirurgie MeSH
- lidé středního věku MeSH
- lidé MeSH
- močový měchýř patologie chirurgie MeSH
- nádorové biomarkery analýza MeSH
- počítačová rentgenová tomografie metody MeSH
- retrospektivní studie MeSH
- senioři MeSH
- trombóza diagnóza MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- jod MeSH
- kontrastní látky MeSH
- nádorové biomarkery MeSH
We have quantum chemically analyzed the structure and stability of archetypal chalcogen-bonded model complexes D2 Ch⋅⋅⋅A- (Ch = O, S, Se, Te; D, A = F, Cl, Br) using relativistic density functional theory at ZORA-M06/QZ4P. Our purpose is twofold: (i) to compute accurate trends in chalcogen-bond strength based on a set of consistent data; and (ii) to rationalize these trends in terms of detailed analyses of the bonding mechanism based on quantitative Kohn-Sham molecular orbital (KS-MO) theory in combination with a canonical energy decomposition analysis (EDA). At odds with the commonly accepted view of chalcogen bonding as a predominantly electrostatic phenomenon, we find that chalcogen bonds, just as hydrogen and halogen bonds, have a significant covalent character stemming from strong HOMO-LUMO interactions. Besides providing significantly to the bond strength, these orbital interactions are also manifested by the structural distortions they induce as well as the associated charge transfer from A- to D2 Ch.
