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Assessing the effect of Diuron herbicide on post juvenile African catfish (Clarias gariepinus) using specific biochemical markers could provide vital information concerning the health status with regards to electrolyte determination. The fishes were subjected to different concentrations of diuron of (0.5, 0.75, 1.0, 1.25, and 1.5mgL-1 respectively) for 96hrs and the alterations in the serum enzymes, metabolites and ion level were determined. The lethal concentration (LC50) value of the herbicide was 1.0mg L-1 for 96h of exposure. During the experiment different behavioural changes were observed and recorded and blood samples were collected after 96hours of experiment to check for the effect of fish exposed to different concentration of diuron herbicide and the parameters observed were serum enzymes (ALT, ALP, AST and LDH). Biochemical examination was also carried out to know the changes in Total protein, glucose and cortisol level. Ion level examination was carried out to assess changes in sodium (Na+), potassium (K+) and chloride (Cl-). It was observed that there were significant differences (P˂0.05) in the serum enzymes analysis, biochemical examination and ion level examination and these parameters revealed differences with varying concentrations of diuron herbicide. Thus, diuron possesses toxicity effects on C. gariepinus Keywords: Herbicide, Clarias gariepinus, serum enzymes

An application of dimethyl urea and L-tartaric acid as deep eutectic solvent (DES) is demonstrated for the synthesis of 2-(methylamino)-3-nitrospiro[chromene] and N-methyl-3-nitro-4H-chromen-2-amin...

The conversion of meso-aryl-porphyrins/chlorins to porphyrinoids containing nonpyrrolic heterocycles (so-called pyrrole-modified porphyrins, PMPs) along an approach we dubbed "the breaking and mending of porphyrins" is well known. However, examples are limited to the synthesis of PMPs containing up to six-membered heterocycles; the syntheses of larger rings failed. We report here hitherto unavailable eight-membered chlorin-type PMPs using an inverted "mending and breaking" approach. All examples are based on the addition of N,N'-dimethylurea derivatives to a meso-phenyl-β,β'-dioxoporphyrin, followed by oxidative cleavage of the intermediate diol adduct. We correlate the extremely nonplanar solid-state structures of three crystallographically characterized PMPs containing an eight-membered ring with their solution-state optical properties. The first examples of bis-modified, bacteriochlorin-type PMPs containing either two eight-membered rings or an eight-membered ring and an imidazolone ring are also detailed. Using other N,N'-nucleophiles failed to either generate chlorins containing a β,β'-dihydroxypyrroline, a prerequisite for the "breaking step," or the cleavage of those substrates that did generate a diol underwent subsequent reactions that thwarted the generation of the desired PMPs. This contribution adds novel PMPs containing eight-membered rings, highlights the effects these derivatizations have on the macrocycle conformation, and how that affects their optical properties.

Biodegradable polymers are already used in many industries due to their environmental benefits, however their use in agriculture is not yet widespread. Herein, a new biodegradable film of crosslinked poly(vinyl alcohol) (PVA)/silk sericin (SS) was explored and used to coat seeds in order to protect seeds from environmental risk factors with the aim to enhance germination. Films of PVA/SS with different loadings of dimethylurea (DMU, crosslinker) and with different concentrations of PVA were fabricated using an organic solvent free casting process. These crosslinked films were characterized for their thickness, morphology, functional groups, mechanical properties, hydrophilicity and swelling. The results found that the crosslinked film composed of 20% w/w DMU, 10% w/v PVA and 2% w/v SS had good mechanical and physical properties due to higher DMU contents promoting greater crosslinking via hydrogen bonding. This film composition was used to coat on lablab bean seeds by a spray rotary coating machine. Coated and non-coated seeds were compared for their imbibition, water vapor uptake and germination. The coated seeds showed higher imbibition and water vapor uptake than non-coated seeds due to the hydrophilic properties of PVA and SS, which helps to promote higher % germination of the coated seeds. This new biodegradable hydrophilic film of crosslinked PVA/SS has potential for use in seed coating technology.

Lignocellulose is a potential raw material for film and membrane applications, such as packaging for every day consumables or a supporting barrier layer for flexible electronics. Here, lignin-containing cationic wood nanofiber (CWNF) films were produced using sawdust as the starting material. Sawdust was directly cationized using four different aqueous solvents containing tetraethylammonium hydroxide with different carbamides (urea, methylurea, ethylurea, or dimethylurea) and glycidyltrimethylammonium chloride as the cationization agent. Cationic wood was obtained with a high cationic group content (around 1.5 mmol g−1) and yield (89–100%), and CWNFs were easily obtained by mechanical disintegration as a water suspension. The films produced using solvent-casting exhibited excellent visible-light transparence (around 80% at 600 nm), and the presence of lignin allowed high UV-adsorption (below 380 nm, transmittance was under 1%). The films showed high oxygen barrier properties (below 400 and 4000 m3 μm/m2 day atm at a relative humidity of 50 and 92%, respectively) and good mechanical strength. An antimicrobial test conducted using the disk method showed that the CWNF films exhibited bacterial anti-adhesive properties with a small inhibition zone. CWNFs are therefore potential environmentally friendly packaging materials to prevent food spoilage, or useful as a UV-absorption layer for electronic devices such as solar cells.

Made available in DSpace on 2021-06-25T12:24:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-10-06 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The main organochlorinated compounds used on agricultural crops are often recalcitrant, affecting nontarget organisms and contaminating rivers or groundwater. Diuron (N-(3,4-dichlorophenyl)-N ',N '-dimethylurea) is a chlorinated herbicide widely used in sugarcane plantations. Here, we evaluated the ability of 13 basidiomycete strains of growing in a contaminated culture medium and degrading the xenobiotic. Dissipation rates in culture medium with initial 25 mg/L of diuron ranged from 7.3 to 96.8%, beingPluteus cubensisSXS 320 the most efficient strain, leaving no detectable residues after diuron metabolism.Pycnoporus sanguineusMCA 16 removed 56% of diuron after 40 days of cultivation, producing three metabolites more polar than parental herbicide, two of them identified as being DCPU and DCPMU. Despite of the strong inductive effect of diuron upon laccase synthesis and secretion, the application of crude enzymatic extracts ofP. sanguineusdid not catalyzed the breakdown of the herbicide in vitro, indicating that diuron biodegradation was not related to this oxidative enzyme. ITAIPU Binac, Div Reservatorio MARR CD, Ave Tancredo Neves 6731, BR-85856970 Foz Do Iguacu, Parana, Brazil Univ Estadual Paulista, Inst Biociencias Letras & Ciencias Exatas, Lab Bioquim & Microbiol Aplicada, Rua Cristovao Colombo 2265, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil Univ Estadual Paulista, Inst Biociencias Letras & Ciencias Exatas, Dept Quim & Ciencias Ambientais, Rua Cristovao Colombo 2265, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil Univ Estadual Paulista, Inst Biociencias Letras & Ciencias Exatas, Lab Bioquim & Microbiol Aplicada, Rua Cristovao Colombo 2265, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil Univ Estadual Paulista, Inst Biociencias Letras & Ciencias Exatas, Dept Quim & Ciencias Ambientais, Rua Cristovao Colombo 2265, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil FAPESP: 06/05411-5

Errors were discovered regarding the published equation coefficients of Zhu and co-workers [J. Chem. Thermodynamics 97 (2016) 9–16] for mathematically describing the solubility behavior of 1,3-dimethylurea in different pure solvents using the Wilson model. Larger differences were found between our back-calculated data and those reported in the authors’ published paper. The expression of Wilson model was corrected and the equation parameters were re-regressed. In addition, the thermodynamic functions of mixing such as change of mixing Gibbs energy, mixing enthalpy and mixing entropy of mixing were re-calculated.

The present study deals with the self-assembly of a pure graft copolymer: Soluplus® and a non-ionic surfactant: Solutol® HS15 and focuses on their clouding behaviour [expressed as cloud point (CP)] in the presence of different additives viz. inorganic salts (NaF, NaCl, NaBr, NaI, NaNO3, KCl, KBr, KI), bile salts (sodium cholate-NaC, sodium taurocholate-NaTC, sodium deoxycholate-NaDC), denaturants (urea, methylurea, dimethylurea), amino acids (alanine, glycine, lysine, valine, cysteine hydrochloride), sugars (glucose, fructose, mannitol, sucrose, maltose, lactose), cationic surfactants (cetyltrimethylammonium bromide-CTAB, tetradecyltrimethylammonium bromide-TTAB, dodecyltrimethylammonium bromide-DTAB) and alcohols (methanol, ethanol, propanol, 1-butanol, ethanediol, 1,3-propanediol, 1,4-butanediol). The aqueous solutions of these amphiphiles show a complex phase behaviour and have revealed the occurrences of spherical micelles using dynamic light scattering (DLS) and small-angle neutron scattering (SANS) techniques. Herein, we report the variation of amphiphilic CP in the presence of different kinds of additives that show the influence of the water structure and its hydrophobicity, making this study important for pharmaceutical/ biomedical applications.

Deep eutectic solvents (DESs) become more attractive in the catalytic field due to their biodegradation, low toxicity, and designability. This study focused on the active sites and influencing fact...

A cariprazine, an oral atypical antipsychotic acting as a D2 and D3 receptor partial agonist, has been crystallized as a free base, trans-N-{4-[2-[4-(2,3-dichlorophenyl)piperazine-1-yl]ethyl]cyclohexyl}-N',N'-dimethylurea, C21H32Cl2N4O (I), and as a chloride salt, trans-N-{4-[2-[4-(2,3-dichlorophenyl)piperazine-1-yl]ethyl]cyclohexyl}-N',N'-dimethylurea hydrochloride, C21H33Cl2N4O+Cl– (II). In both structures, the cariperazine molecule is in an extended conformation. The dimethylurea group exhibits a syn conformation of the O atoms in the I, whereas an almost anti orientation is present in the II. Two terminal groups, dimethylurea and dichlorophenyl ring, are oriented differently in the I and II. The cariprazine molecules in the I are linked into an infinite zigzag chains by N–H···O hydrogen bonds, where the neighboring cariprazine molecules form an L-shape configuration. In the II, the molecules of cariprazine are connected with the chloride anion by N–H···Cl charge-assisted hydrogen bonds, which are further stabilized by weak intermolecular interactions, forming horizontal molecular chain along the b axis. This study reveals the variations in the solid-state conformation of cariprazine molecule in different crystalline environments.

We present a method to simultaneously measure the film thickness and individual concentrations of two urea derivates (urea C H 4 N 2 O and dimethylurea C 3 H 8 N 2 O ) mixed in an aqueous solution at constant temperature using near-infrared (NIR) absorption at multiple specific wavelengths. Fourier transform infrared (FTIR) spectra of aqueous mixtures of urea and dimethylurea solutions were recorded in the 1250–2500 nm wavelength range in thin-layer quartz cuvettes at room temperature. The spectra reveal suitable detection wavelengths, i.e., 1450, 1933, 2200, and 2270 nm, for which both the absorption coefficient and its variation with the species concentration are large enough to achieve satisfactory detection sensitivity and selectivity. For validation measurements, samples were prepared in thin-layer quartz transmission cells with known path lengths and mixture compositions in the range 100–1000 µm and 0–40 wt.%, respectively. Film thickness and mass fractions of both species were determined from measured absorbance ratios in the determined characteristic wavelength bands.

Three new succinate-containing complexes of uranyl with carbamide (Urea) and N,N'-dimethylurea (s-Dmur) are synthesized and studied by IR spectroscopy and X-ray diffraction. Structures of the same type, [UO2(Urea)4(H2O)][(UO2)2(C4H4O4)3] · 3H2О and [UO2(Urea)4(H2O)][(UO2)2(C4H4O4)3] · 2Urea contain two sorts of uranium-containing complex groups, namely, mononuclear [UO2(Urea)4(H2O)]2+ cations and two-dimensional [(UO2)2(C4H4O4)3]2– anions described by crystal-chemical formulas AМ 5 1 and A 2 Q 3 02, respectively (A = UO2 2+, M 1 = Urea or H2O, Q 02 = C4H4O4 2-), and differ only in the nature of noncoordinated molecules—water and carbamide. The main structural groups of the [(UO2)2(C4H4O4)2(s-Dmur)3] crystals are [(UO2)2(C4H4O4)2(s-Dmur)3] chains belonging to the А 2 Q 2 02 M 3 1 (A = UO2 2+, Q 02 = C4H4O4 2-, M 1 = s-Dmur) crystal-chemical group. Specific features of intermolecular interactions in the crystal structures are revealed using the Voronoi–Dirichlet method of molecular polyhedra.

Microalgae are attracting much attention as superior biodiesel producers. In particular, under stressful conditions, they accumulate organic compounds consisting entirely of carbon and hydrogen. The aim of this work was to increase intracellular fatty acid content in Dunaliella tertiolecta (Chlorophyceae), Nannochloropsis oculata (Eustigmatophyceae), and Porphyridium cruentum (Rhodophyceae) using a combination of nitrogen starvation and chemical inhibitors of carbohydrate biosynthesis. These microalgae were subjected to nitrogen starvation and their physiological changes were then observed over time. In D. tertiolecta, no significant change in total fatty acid content was detected on day 3.5 relative to the initial total fatty acid content (day 0), while total carbohydrate content dramatically increased as the nitrogen starvation period was extended. In N. oculata, total fatty acid content rapidly increased, reaching up to nearly 40% of the DCW at day 3.5. However, total carbohydrate content exhibited a gradual reduction throughout the experiment. In P. cruentum, total carbohydrate content increased up to 43% of DCW on day 3.5 and total fatty acid content increased slightly under nitrogen depletion. These data suggest that different eukaryotic microalgae use different storage products under stressful conditions. Among the three strains, D. tertiolecta showed decreased total carbohydrate content and enhanced total fatty acid content following inhibition of carbohydrate synthesis by dichlorophenyl dimethylurea and cyclohexane diamine tetra acetic acid. The results demonstrate the possibility of furthering our understanding of the fatty acid and carbohydrate biosynthesis metabolic network that responds to environmental changes in microalgae.

The influence of the amphiphile 1,3-dimethylurea (1,3-DMU) on the dynamic properties of water was studied using dielectric relaxation spectroscopy. The experiment provided evidence for substantial retardation of water reorientation in the hydration shell of 1,3-DMU, leading to a separate slow-water relaxation in addition to contributions from bulk-like and fast water as well as from the solute. From the amplitudes of the resolved water modes effective hydration numbers were calculated, showing that each 1,3-DMU molecule effectively freezes the reorientation of 1–2 water molecules. Additionally, a significant amount of solvent molecules, decreasing from ∼39 at infinite dilution to ∼3 close to the solubility limit, is retarded by a factor of ∼1.4 to 2.3, depending on concentration. The marked increase of the solute amplitude indicates pronounced parallel dipole alignment between 1,3-DMU and its strongly bound H2O molecules. Molecular dynamics (MD) simulations of selected solutions revealed a notable slowdown of water rotation for those solvent molecules surrounding the methyl groups of 1,3-DMU and strong binding of ∼2H2O by the hydrophilic carbonyl group, corroborating thus the experimental results. Additionally, the simulations revealed 1,3-DMU self-aggregates of substantial lifetime.

This study presents the use of a reactive deep eutectic solvent (DES) for the chemical modification of wood cellulose fibers. DES based on dimethylurea and ZnCl2 was used to synthetize cellulose methyl carbamate (CMeC). This synthesis was performed at elevated temperature under solvent-free conditions. Chemical characterization based on FTIR and NMR indicated that methyl carbamate was successfully introduced to cellulose, and a degree of substitution (DS) of 0.17 was obtained after 3 h of reaction at 150 °C. The product with a DS of 0.17 exhibited good alkaline solubility (in 3 % NaOH solution) after freeze-thawing, whereas the original cellulose fibers were practically insoluble even in 9 % NaOH. As dimethylurea can be produced from CO2, this method can be used as a sustainable way to obtain novel cellulose materials with desirable properties for use in a wide range of applications.

Soft X-ray emission (XE), absorption (XA), and resonant inelastic scattering (RIXS) experiments have been conducted at the nitrogen K-edge of urea and its derivatives in aqueous solution and were compared with density functional theory and time-dependent density functional theory calculations. This comprehensive study provides detailed information on the occupied and unoccupied molecular orbitals of urea, thiourea, acetamide, dimethylurea, and biuret at valence levels. By identifying the electronic transitions that contribute to the experimental spectral features, the energy gap between the highest occupied and the lowest unoccupied molecular orbital of each molecule is determined. Moreover, a theoretical approach is introduced to simulate resonant inelastic X-ray scattering spectra by adding an extra electron to the lowest unoccupied molecular orbital, thereby mimicking the real initial state of the core-electron absorption before the subsequent relaxation process.

In this work, solubility data of 1,3-dimethylurea (DMU) in methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol were measured by synthetic method from T = 288.15 to 328.15 K at ordinary pressure. It turned out that the solubility data increased as temperature and solvent polarity increased. The molecular interactions in solution have been studied by the linear energy relationship. Furthermore, based on two thermodynamic models (i.e., modified Apelblat and Wilson), the experimental results were fitted and analyzed. Finally, the thermodynamic properties of solution, including entropy, enthalpy, and Gibbs energy were calculated. These results indicate that in all selected solvents the dissolution behavior were endothermic, entropy-driven, and not spontaneous.

The compounds UO2(C2H5COO)2·1.5L, where L is methylurea (Meur) or N,N’-dimethylurea (s-Dmur), were synthesized and studied by IR spectroscopy and single crystal X-ray diffraction. Irrespective of the kind of amide L, the structure of the compounds consists of two mononuclear uranium-containing complexes: cationic [UO2(prop)L3]+ and anionic [UO2(prop)3]–, where prop is propionate ion. Both compounds belong to crystal-chemical group AB01M31+ AB01M301 (A = UO22+, B01 = prop–, M1 = L) of uranyl complexes. The composition of 15 stable uranyl complexes that can be formed in the UO22+, B01–prop––L–H2O system was predicted on the basis of the characteristics of the Voronoi–Dirichlet polyhedra from the standpoint of the 18-electron rule.

Measurements of the binary mixture {water (1) + 1,3-dimethylurea (2)} density within the temperature range of 274.15 to 333.15 K were performed within a wide range of compositions at the atmospheric pressure by using the density gauge with a U-shaped vibrating tube. There are calculated apparent and partial molar volumes of water and 1,3-dimethylurea (1,3-DMU) in the mixture, limiting (standard) partial molar volumes of 1,3-DMU in water, molar isobaric thermal expansion of the mixture and molar isobaric thermal expansion of 1,3-DMU at infinite dilution. It is shown that concentration dependences of partial molar volumes of the water and 1,3-DMU are characterized by the presence of extremums thus revealing manifestation of hydrophobic nature of the 1,3-dimethylurea molecule. Limiting partial molar volumes of 1,3-DMU increase with the increase of the temperature. Increasing both the temperature and the concentration of 1,3-DMU lids to the increasing of the molar isobaric expansion of the mixture. The obtained results are discussed in terms of the solute – solvent and solute – solute interactions. A comparison of the obtained characteristics with similar characteristics of the urea, N-methylurea and tetramethylurea is performed.

There has been a surge in interest and research in the arena of utilizing deep eutectic solvents (DESs) as green solvents for removal of SO2 in recent years. In this work, an effective strategy for SO2 reversible capture and fixation by four amides based DESs was demonstrated. These DESs are composed of 1-ethyl-3-methylimidazolium chloride (EmimCl) and dimethylurea (DMU), N-methylurea (MU), thioacetamide (SAA), or caprolactam (CLAA) in a 2:1 M ratio, which achieve both high gravimetric and molar absorption capacity of SO2 at 20 °C and 1.0 bar (up to 1.26 g per gram of DES, or 8.00 mol per mole of DES). Results of the NMR and FTIR spectra reveal that there are physical interactions between SO2 and DESs. Furthermore, absorbed SO2 can be desorbed and no significant drop in SO2 absorption was observed after five successive absorption–desorption cycles. Particularly, the absorbed SO2 was quickly converted in situ into the charge-transfer complex of bis(sulfur dioxide)-1,4-diazabicyclo[2.2.2]octane adduct (DABCO·2SO2) as a high value-added chemical. The SO2-lean phase was directly reused for SO2 capture, thus greatly reducing energy requirements and providing a promising method SO2 resource utilization.

Amphetamine-type substances (ATS) are the most common illicit drugs synthesised in domestic clandestine laboratories. Liquid-liquid extraction of exhibits remains a key step in the analysis of exhibits, with chloroform often the solvent of choice in clandestine laboratory analysis. The decomposition of chloroform to phosgene is well known, with artefacts from extraction with phosgene-contaminated chloroform reported in the literature. This laboratory has observed artefacts upon the phosgene-contaminated chloroform extraction of ATS, some of which are in contrast to those reported in the literature by previous authors and which were not identified in the current literature. This paper presents the synthesis and characterisation of the previously unreported artefacts 1-methyl-2-phenethyl isocyanate, N,N'-bis(1-methyl-2-phenethyl) urea, N,N'-bis(1-methyl-2-phenylethyl)-N,N'-dimethylurea, 1-methyl-2-(3,4-methylenedioxy-phenyl)ethyl isocyanate and N,N'-bis(1-methyl-2-(3,4-methylene-dioxyphenyl)ethyl)-N,N'-dimethylurea from amphetamine, methylamphetamine, 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethylamphetamine (MDMA), respectively.

Reductive electrosynthesis has faced long-standing challenges in applications to complex organic substrates at scale. Here, we show how decades of research in lithium ion battery materials, electrolytes, and additives can serve as an inspiration for achieving practically-scalable reductive electrosynthetic conditions for the Birch reduction. Specifically, we demonstrate that using a sacrificial anode material (Mg or Al), combined with a cheap, non-toxic, and water-soluble proton source (dimethylurea), and an overcharge protectant inspired by battery technology (tris(pyrrolodino)phosphoramide) can allow for multigram-scale synthesis of pharmaceutically-relevant building blocks. We show how these conditions have an exceptional level of functional-group tolerance relative to classical electrochemical and chemical dissolving metal reductions. Finally, we demonstrate that the same electrochemical conditions can be applied to other dissolving-metal-type reductive transformations, including McMurry couplings, reductive ketone deoxygenations, and reductive epoxide openings.

Photophysical and electrochemical techniques were employed to hydrogen-bonding self assemblies forming solutes (Urea, Dimethylurea and Tetramethylurea) in the presence of 4-dicyanomethylene 2, 6-dimethyl-4H-pyran (DDP) dye. Addition of urea derivatives to DDP dye (Intramolecular Charge Transfer (ICT)) results in a fluorescence enhancement accompanied with a significant shift. Fluorescence lifetime behavior exhibits a tri-exponential decay with a large variation in the fluorescence lifetime and relative amplitude distribution. The coexistence of three different fluorescence lifetime components of DDP with urea derivatives signifies the existence of heterogeneous micro environment. The dye is surrounded by varying proportion of solute and water molecules are established from fluorescence lifetime studies. Urea derivatives govern the excited state characteristics of DDP dye resulting in the formation and promotion of different microenvironment which are clearly distinguishable. The existence of multi environment attributed to urea-water structural behaviour is authenticated by electrochemical impedance spectral studies (EIS). A large variation in the contour pattern, shape and intensity in 3D fluorescence contour spectra of dye with urea validate the existence of dye in a heterogeneous micro environment. The hydrophobicity of urea derivatives along with the hydrogen-bonding properties of urea-water and urea-urea influence the photophysical and electrochemical nature of dye is emphasized.

Urea-formaldehyde (UF) resins are the most used resins in the wood industry due to high reactivity and low price. However, their reduced stability during storage is a drawback, imposing strict limits in terms of allowable shipping distances and storage times. This instability, manifested by viscosity increase that renders the resin unusable, occurs due to the progress of condensation reactions between the polymeric species present in the liquid medium. In order to achieve a stable resin formulation, dimethylurea (DMeU) was selected for being less reactive than urea. Dimethylurea is shown to co-polymerize with the UF polymer during the acidic synthesis condensation step. However, during storage it behaves like an end group blocker, due to its lower reactivity at basic pH. By adding 1.25% DMeU, it was possible to obtain a formulation that remained with stable viscosity during two-month storage at 40 &deg, C. The reference UF resin remained stable only for eight days in these conditions. Wood particleboards produced with modified resins showed internal bond strengths of about 0.5 N&middot, mm&minus, 2, similar to the fresh reference UF resin, even when the resins were used after the two-month storage period. Formaldehyde content values were below the limit for E1 class, &le, 8 mg/100 g oven dry board (EN 13986).

Cold acclimation modifies the photosynthetic machinery and enables plants to survive at sub-zero temperatures, whereas in warm habitats, many species suffer even at non-freezing temperatures. We have measured chlorophyll a fluorescence (ChlF) and CO2 assimilation to investigate the effects of cold acclimation, and of low temperatures, on a cold-sensitive Arabidopsis thaliana accession C24. Upon excitation with low intensity (40 µmol photons m− 2 s− 1) ~ 620 nm light, slow (minute range) ChlF transients, at ~ 22 °C, showed two waves in the SMT phase (S, semi steady-state; M, maximum; T, terminal steady-state), whereas CO2 assimilation showed a linear increase with time. Low-temperature treatment (down to − 1.5 °C) strongly modulated the SMT phase and stimulated a peak in the CO2 assimilation induction curve. We show that the SMT phase, at ~ 22 °C, was abolished when measured under high actinic irradiance, or when 3-(3, 4-dichlorophenyl)-1, 1- dimethylurea (DCMU, an inhibitor of electron flow) or methyl viologen (MV, a Photosystem I (PSI) electron acceptor) was added to the system. Our data suggest that stimulation of the SMT wave, at low temperatures, has multiple reasons, which may include changes in both photochemical and biochemical reactions leading to modulations in non-photochemical quenching (NPQ) of the excited state of Chl, “state transitions,” as well as changes in the rate of cyclic electron flow through PSI. Further, we suggest that cold acclimation, in accession C24, promotes “state transition” and protects photosystems by preventing high excitation pressure during low-temperature exposure.

Vinca alkaloids are chemotherapeutic agents used in the treatment of both pediatric and adult cancer patients. Cytochrome P450 3A5 (CYP3A5) is 9- to 14-fold more efficient at clearing vincristine than cytochrome P450 3A4 (CYP3A4) is. However, patients who express an inactive form of the polymorphic CYP3A5 enzyme suffer from severe neurotoxicity during vincristine treatment, resulting in chemotherapy failure. Previous studies have found that the addition of new features to the parent drug can enhance its binding affinity to tubulin manyfold and could therefore yield novel anticancer drugs. However, there is no report of any study of the metabolic activities of CYP3A4 and CYP3A5 with respect to vincristine and vinblastine, so we studied the interactions of these two drugs and 15 vinca derivatives with CYP3A4 and CYP3A5 by performing docking studies using GOLD. Six of the vinca derivatives in complexes with CYP3A4 and CYP3A5 were further investigated in 100-ns molecular dynamic simulations. Interaction energies, hydrogen bonds, and linear interaction energies were calculated and principal component analysis was carried out to visualize the binding interface in each complex. The results indicate that the addition of dimethylurea at the C20' position in vincristine may increase its binding affinity and lead to enhanced interactions with the less polymorphic CYP3A4 rather than CYP3A5. Thus, dimethylurea vincristine may be a useful drug in cancer chemotherapy treatment as it should be significantly less likely than vincristine to induce severe neurotoxicity in patients. Graphical Abstract Proposed modification of Vinca alkaloid derivatives to decrease the neurotoxicity level in cancer patients exhibiting CYP3A4 gene rather than polymorphic CYP3A5 gene.

To explore environmentally friendly and benign solvents to capture NO gas, a series of ionic liquids was newly synthesized by 1,3-dimethylurea and tetrabutylphosphonium bromide with different mole ratios (1:1, 2:1, and 3:1). In addition, their NO absorption and desorption properties were studied at a temperature from 30 to 70 °C and atmospheric pressure for the first time. These synthesized ionic liquids exhibited excellent reversibility and high NO solubility, such as 1.173 mol of absorbed NO/mol of ionic liquids (3:1) at 40 °C and 101.3 kPa. The solubility of NO in these synthesized ionic liquids increased with the increase of the mole ratios of 1,3-dimethylurea in ionic liquids and also with the decrease of the temperature. The studies of Fourier transform infrared spectroscopy (FTIR) and 1H and 13C nuclear magnetic resonance (NMR) spectra revealed that it is a reversible chemical process for these ionic liquids to capture NO gas; therefore, we proposed a reversible chemical absorption mechanism. These...

A new organic material, N,N′dimethylurea ninhydrin (3a,8a-dihydroxy-1,3-dimethyl-1,3,3a,8a-tetrahydroindeno[2,1-d]imidazole-2,8-dione) (NDUN) was synthesized. Structural details were obtained from single crystal X-ray diffraction (XRD) data. A detailed interpretation of the vibrational spectra is carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology. TG/DTA and 1H NMR studies were carried out. Linear optical properties were studied from UV–Vis spectra. From the open aperture Z-scan data, it is found that the molecule shows third order nonlinear optical behaviour due to two photon absorption (2PA) mechanism.

The compounds [(UO2)2(C5O4H6)2(urea)2(H2O)]·H2O (I) and [UO2(C5O4H6)(s-Dmur)] (II), where C5O4H 6 2- is glutarate ion and s-Dmur is N,N'-dimethylurea, were synthesized and studied by IR spectroscopy and single crystal X-ray diffraction. The structure of I consists of electrically neutral [(UO2)2(C5O4H6)2(urea)2·(H2O)] ribbons belonging to the A2Q21Q02M 3 1 crystal-chemical group (A = UO 2 2+ , Q21 and Q02 = C5O4H 6 2- , M1 = urea or H2O) of uranyl complexes. The structure of II contains [UO2(C5O4H6)(s-Dmur)] chains belonging to the AQ21M1 group (A = UO 2 2+ , Q21 = C5O4H 6 2- , M1 = s-Dmur). The specific features of intermolecular interactions in the structures of the crystals of I and II were characterized using the method of molecular Voronoi–Dirichlet polyhedra.

Quantitative on-line NMR spectroscopy is applied to study equilibria and reaction kinetics of the reaction of formaldehyde with 1,3-dimethylurea. This reaction system serves as a model system for the much more complex but industrially relevant urea-formaldehyde system. The aim is to study individual reactions and intermediates. The 1,3-dimethylurea-formaldehyde system undergoes only four reactions and, unlike urea-formaldehyde, does not form polymers. The following reactions are studied in detail: (1) the hydroxymethylation, (2) the formation of hemiformals of the hydroxymethylated intermediate, and (3) two condensation reactions of which the first leads to methylene bridges, the other to ether bridges. NMR spectroscopic chemical shift data of the reacting species are provided for the (1) H, (13) C, and (15) N domains. Equilibrium data of reactions (1), (2), and (3) are determined by quantitative (1) H and (13) C NMR spectroscopy at molar ratios of formaldehyde to 1,3-dimethylurea between 1:2 and 16:1 at a pH value of 8.5. Reaction kinetic experiments using an NMR spectrometer coupled to a batch reactor led to a reaction kinetic model parametrized with true species concentrations. The model takes into account reactions (1), (2), and (3). It describes the reaction system well for molar ratios of 1:1, 2:1, and 4:1, temperatures of 303 to 333K, and pH values from 5.0 to 9.5. Dilution experiments with a micro mixer coupled to the NMR spectrometer are conducted to estimate the time to equilibrium of reaction (2) of which the time constant is significantly lower than those of reactions (1) and (3). Copyright © 2015 John Wiley & Sons, Ltd.

C24H25ClN2O2, orthorhombic, P212121 (no. 19), a = 5.9066(2) Å, b = 15.7928(3) Å, c = 21.7829(6) Å, V = 2031.95(10) Å3, Z = 4, R gt(F) = 0.0319, wR ref(F 2) = 0.0838, T = 150(2) K.

Time courses of photochemical reflectance index (PRI) of an attached cucumber leaf during a dark-light transition were compared with those of photochemical yields of photosystem II (YII ) to discuss the feasibility of PRI imaging for estimating the efficiency of photosynthetic light use. YII and PRI were simultaneously evaluated with a pulse-amplitude modulation chlorophyll fluorometer and a low-cost imaging system consisting of digital cameras and band-pass filters, respectively. YII decreased immediately after the transition and then increased under various photon flux densities. Although PRI exhibited delayed time courses with respect to YII under low light conditions, PRI decreased monotonically under high light conditions. There was no correlation between YII and the changes in PRI (ΔPRI) immediately after the transition but YII was correlated with ΔPRI under the steady-state photosynthesis. These results indicate that the use of PRI to estimate YII under fluctuating light based on the regression obtained at steady state can overestimate YII . The imaging system was also applied to evaluate the spatial PRI distribution within a leaf. While PRI of leaf areas that remained untreated, or had been treated with H2 O again, first dropped and then rose under low light and monotonically decreased under high light conditions, leaf areas treated with inhibitor (dichlorophenyl dimethylurea) did not exhibit any changes. It is likely that the inhibitor suppressed lumen acidification, which triggers a decrease in PRI. It was suggested that YII of leaves with malfunctions in the photosynthetic electron transport can be overestimated by the PRI-based estimation.

The present study focuses on the ability of excipients to induce the crystallization of a specific polymorphic form of pyrazinamide (PZA) and more interestingly, to block the irreversible solid–solid transition of the metastable forms of the PZA to the stable form at room temperature. We outline an experimental protocol for the production of a structurally pure γ form of PZA by means of spray drying. Without any particular treatment, phase transition to δ form was detected after 14 days of storage under ambient conditions. In order to prevent this irreversible phase transition, different excipients were co-spray dried with PZA. By co-spray drying 5% in mass of 1,3-dimethylurea (DMU) with PZA, we noticed its ability in preventing phase transitions and thus to maintain PZA under its γ form up to 12 months of storage at room temperature. Raman spectroscopy evidenced how DMU crystals surround particles of γ PZA which suggest that DMU might interact with the surface of PZA particles, thus blocking the phase transition. On the other hand, the co-spray drying of PZA with the polymerpolyvinylpyrrolidone (PVP) resulted in the crystallization of δ form of PZA. The physical mixture was intact over 12 months of storage at room temperature.

The characteristic absorption spectra of two structural isomers of dimethylurea(DMU) in 0.6–1.8 THz region have been measured using terahertz time-domain spectroscopy (THZ-TDS) at room temperature. Significant differences have been found between their terahertz spectra and implied that the THZ-TDS is an effective means of identifying structural isomers. To simulate their spectra, calculations on single molecule and cluster of 1,1-DMU and 1,3-DMU were performed, and we found that the cluster calculations using DFT-D3 method are better to predict the experimental spectra. Using the normal mode as displacements in redundant internal coordinates and the GaussView program, most observed THz vibrational modes are assigned to bending and rocking modes related to the intermolecular hydrogen bonding interactions, and twisting mode of ethyl groups. The different spectral features of two isomers mainly arise from different intermolecular hydrogen bonds resulting from different atom arrangements in molecules and different molecule arrangements in crystals. Using the reduced-density-gradient (RDG) analysis, the positions and types of intermolecular hydrogen bonding interactions in 1,1-DMU and 1,3-DMU crystals are visualized. Therefore, we can confirm that THz-TDS can be used as an effective means for the recognition of structural isomers and detection of intermolecular hydrogen bonding interactions in these crystals.

To understand the mechanism of photosynthetic inhibition and generation of reactive oxygen species (ROS) inSymbiodiniumtypes under stress, chemicals such as dichlorophenyl dimethylurea (DCMU) are widely used. Moreover, DCMU and recently menthol were used to generate aposymbiotic cnidarian hosts. While the effects of DCMU onSymbiodiniumcells have been extensively studied, no studies have shown the mechanism behind menthol-induced coral bleaching. Moreover, no study has compared the effects of DCMU and menthol treatments on photosystem II (PSII) activity and generation of ROS in differentSymbiodiniumtypes. In this study, we utilized five freshly isolatedSymbiodiniumtypes (S. minutum(B1),S. goreaui(C1), C3, C15, andS. trenchii(D1a)) to compare the effects of DCMU and menthol treatments.Symbiodiniumcells were exposed to DCMU and menthol at different concentrations for 4 h. Results showed that values of the 50% inhibitory concentration (IC50) for PSII inhibition were 0.72∼1.96 mM for menthol-treated cells compared to 29∼74 pM for DCMU-treated cells. Diverse responses ofSymbiodiniumtypes were displayed in terms of PSII tolerance to menthol (S. minutum>S. trenchii= C15 > C3 =S. goreaui), and also in the response curves. In contrast, responses were not so diverse when the different types were treated with DCMU. Three of five menthol-treatedSymbiodiniumtypes showed instant and significant ROS generation when PSII activity was inhibited, compared to no ROS being generated in DCMU-treatedSymbiodiniumtypes. Both results indicated that menthol inhibitedSymbiodiniumPSII activity throughSymbiodiniumtype-dependent mechanisms, which were also distinct from those with DCMU treatment. This study further confirmed that photosynthetic functionsSymbiodiniumhave diverse responses to stress even within the same clade.

Urea transporters (UTs) are transmembrane proteins that transport urea molecules across cell membranes and play a crucial role in urea excretion and water balance. Modeling the functional characteristics of UTs helps us understand how their structures accomplish the functions at the atomic level, and facilitates future therapeutic design targeting the UTs. This study was based on the crystal structure of Desulfovibrio vulgaris urea transporter (dvUT). To model the binding behavior of urea molecules in dvUT, we constructed a cooperative binding model. To model the substitution of urea by the urea analogue N,N'-dimethylurea (DMU) in dvUT, we calculated the occupation probability of DMU along the urea pore and the ratio of the occupation probabilities of DMU at the external (Sext) and internal (Sint) binding sites, and we established the mutual substitution rule for binding and substitution of urea and DMU. Based on these calculations and modelings, together with the use of the Monte Carlo (MC) method, we further modeled the urea flux in dvUT, equilibrium urea binding to dvUT, and the substitution of urea by DMU in the dvUT. Our modeling results are in good agreement with the existing experimental functional data. Furthermore, the modelings have discovered the microscopic process and mechanisms of those functional characteristics. The methods and the results would help our future understanding of the underlying mechanisms of the diseases associated with impaired UT functions and rational drug design for the treatment of these diseases.

A novel organic nonlinear optical (NLO) material viz. N,N-dimethylurea picrate (NNDMP) was grown by the slow evaporation technique using N,N-dimethyl formamide as a solvent. The solubility of the grown sample has been estimated for various temperatures. The XRD study reveals that the grown crystal crystallizes in the monoclinic crystal system and the corresponding lattice parameters were determined. The relative second harmonic generation (SHG) efficiency of the NNDMP was found to be 1.045 times that of KDP by Kurtz–Perry powder technique. FTIR and FT-Raman spectral analyses explain the various functional groups present in the sample. The optical spectral analysis of the grown crystal has been performed by UV–vis–NIR spectroscopy and the band gap energy was found out. The thermogravimetric analysis and differential thermal analysis (TG/DTA) reveal that the NNDMP crystal is stable at up to 172 °C. A prominent first-order ferroelectric to paraelectric phase transition at 323 K has been observed and activation energy was determined for the AC conduction process in the sample.