Liquid amine–solid carbamic acid phase-separation system for direct capture of CO2 from air

The phase separation between a liquid amine and the solid carbamic acid exhibited >99% CO2 removal efficiency under a large-scale gas stream of 400 ppm CO2. Isophorone diamine [IPDA; 3-(aminomethyl)-3,5,5-trimethylcyclohexylamine] reacted with CO2 in the CO2/IPDA molar ratio of ≥ 1 even in H2O as a solvent. The captured CO2 was completely desorbed at 333 K because the disolved carbamate ion releases CO2 at low temperature. The reusability of IPDA under CO2 adsorption-and-desorption cycles without degradation, the >95% efficinecy kept for 100 hours under direct air capture condition, and high CO2 capture rate (214 mmol/h for 1 mol amine) suggest that the phase separation system using IPDA is robust and durable for practical use.

The Influence of AA29504 on GABAA Receptor Ligand Binding Properties and Its Implications on Subtype Selectivity

The unique pharmacological properties of δ-containing γ-aminobutyric acid type A receptors (δ-GABAARs) make them an attractive target for selective and persistent modulation of neuronal excitability. However, the availability of selective modulators targeting δ-GABAARs remains limited. AA29504 ([2-amino-4-(2,4,6-trimethylbenzylamino)-phenyl]-carbamic acid ethyl ester), an analog of K+ channel opener retigabine, acts as an agonist and a positive allosteric modulator (Ago-PAM) of δ-GABAARs. Based on electrophysiological studies using recombinant receptors, AA29504 was found to be a more potent and effective agonist in δ-GABAARs than in γ2-GABAARs. In comparison, AA29504 positively modulated the activity of recombinant δ-GABAARs more effectively than γ2-GABAARs, with no significant differences in potency. The impact of AA29504's efficacy- and potency-associated GABAAR subtype selectivity on radioligand binding properties remain unexplored. Using [3H]4'-ethynyl-4-n-propylbicycloorthobenzoate ([3H]EBOB) binding assay, we found no difference in the modulatory potency of AA29504 on GABA- and THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol)-induced responses between native forebrain GABAARs of wild type and δ knock-out mice. In recombinant receptors expressed in HEK293 cells, AA29504 showed higher efficacy on δ- than γ2-GABAARs in the GABA-independent displacement of [3H]EBOB binding. Interestingly, AA29504 showed a concentration-dependent stimulation of [3H]muscimol binding to γ2-GABAARs, which was absent in δ-GABAARs. This was explained by AA29504 shifting the low-affinity γ2-GABAAR towards a higher affinity desensitized state, thereby rising new sites capable of binding GABAAR agonists with low nanomolar affinity. Hence, the potential of AA29504 to act as a desensitization-modifying allosteric modulator of γ2-GABAARs deserves further investigation for its promising influence on shaping efficacy, duration and plasticity of GABAAR synaptic responses.

A review: The utilization and its benefits of liquid smoke from lignocellulosic waste

In the integrated charcoal technology, the smoke arising from the process is flowed into a pipe which is cooled, so that the smoke turns into a liquid, so it is called liquid smoke. Therefore, the technology to produce liquid smoke is environmentally friendly. The raw material used in the process of making wood vinegar is generally in the form of lignocellulose waste which contains lignin and cellulose such as wood waste, bamboo waste, oil palm shell waste, coconut shell waste and others. With simple technology input, liquid smoke can be produced from this waste, which has many benefits. The method to produce the liquid smoke was through a process of charcoal or pyrolysis which produces three forms of solid products, namely charcoal, products in the form of gases, namely smoke, and products in the form of liquids, so called tar and liquid smoke; and the main component as a characteristic of liquid smoke were acetic acid, phenolic and carbamic acid. Phenol is the compound that plays the most role in liquid smoke, because it is antibacterial and antifungal and inhibits fat oxidation. Therefore, liquid smoke with its various benefits can be a solution for the problems of pets and bacteria in agriculture or environmental pollution.

Urease Inhibitory Kinetic Studies of Various Extracts and Pure Compounds from Cinnamomum Genus

Urease is an enzyme that plays a significant role in the hydrolysis of urea into carbonic acid and ammonia via the carbamic acid formation. The resultant increase in pH leads to the onset of various pathologies such as gastric cancer, urolithiasis, hepatic coma, hepatic encephalopathy, duodenal ulcers and peptic ulcers. Urease inhibitors can reduce the urea hydrolysis rate and development of various diseases. The Cinnamomum genus is used in a large number of traditional medicines. It is well established that stem bark of Cinnamomum cassia exhibits antiulcerogenic potential. The present study evaluated the inhibitory effect of seven extracts of Cinnamomum camphora, Cinnamomum verum and two pure compounds Camphene and Cuminaldehyde on urease enzyme. Kinetic studies of potential inhibitors were carried out. Methanol extract (IC50 980 µg/mL) of C. camphora and a monoterpene Camphene (IC50 0.147 µg/mL) possess significant inhibitory activity. The Lineweaver Burk plot analysis suggested the competitive inhibition by methanol extract, hexane fraction and Camphene. The Gas Chromatography-Mass Spectroscopy (GC–MS) analysis of hexane fraction revealed the contribution of various terpenes. The present study targets terpenes as a new class of inhibitors that have potential therapeutic value for further development as novel drugs.

DEVELOPMENT OF METHODS FOR QUANTITATIVE DETERMINATION OF ALBENDAZOLE AND ITS METABOLITES IN BIOLOGICAL TISSUES USING HPLC / FLD

This manuscript presents the results of developed method is intended for clinical and pharmaceutical studies of veterinary drugs based on the active substances albendazole ([5-(propylthio)-1H-benzimidazol-2yl]carbamic acid methyl ester) and its main metabolites, albendazole sulfoxide, albendazole sulfone, and albendazole-2- aminosulfone in sheep muscles. Tissue samples were made alkaline with sodium carbonate, extracted twice with acetonitrile and degreased with hexane. The extracts are further purified using a series of liquid-liquid extraction and solid phase extraction. After concentration and drying, the dry residue was recovered in the mobile phase. Separation was performed on an inverted phase Acclaim 120 C18 column using acetonitrile and phosphate buffer as the mobile phase. The gradient mode of eluents was used during 12 min at a flow rate of 1,8 ml/min. The peak retention time of albendazole 2-aminosulfoam is 3,0 min, albendazole sulfoxide is 3,9 min, albendazole sulfone is 4,8 min, and the retention time of albendazole peak is 6,6 min. The specificity of the analytical method was checked by comparing the chromatographic separation of a sample of muscle tissue enriched with a standard solution of a mixture of albendazole and its metabolites at the level of MDR (100 μg/kg) and a sample of muscle tissue placebo. The validation parameters of the method “recovery” and “coefficient of variation” were considered in accordance with the criteria of Council Directive 2002/657/EC. The procedure of sample preparation of fortified tissues to construct calibration graphs is described in the manuscript. The mean recovery from fortified muscle tissue in the range of 50-150 μg/kg albendazole, albendazole sulfoxide, albendazole sulfone and albendazole 2-aminosulfon was 100.2; 100.9; 100.7 and 100.2%, respectively. The average coefficient of variation for each compound was ≤ 10%. The method is linear in the concentration range of 25.0 - 200.0 μg/kg of each analyte. The results obtained in the study of the linearity of this technique were used to estimate the correctness and convergence. The accuracy of the measurements was evaluated by examining the known amounts of analytes added to the control muscle tissue. Recovery data are acceptable because they are within ± 10% of the target value. The method has sufficient convergence (accuracy). The evaluation of the intermediate accuracy of albendazole and its metabolites was assessed on three different days of analysis. The limit of detection for albendasole is 0.4 μg/kg. The average CV for each compound was <10%. The procedure was confirmed and then applied to determination albendazole and its metabolites in the sheep muscle tissue obtained after feeding animals with the veterinary drug albendazole. The HPLC/FLD method can be used for withdrawal time albendazole and its metabolites.

Biological activity of benzoxazolinone and benzoxazolinthione derivatives

The article presents the herbicidal, defoliating, fungicidal properties of the synthesized derivatives of benzoxazolinones and benzoxazolinethions. It was shown that 3-alkylbenzoxazolinones, 3-alkyl-6-halobenzoxazolinones and 2-alkylthiobenzoxazoles exhibit herbicidal action during the growing season of plants, and they also cause cotton leaves to drop up to 70%. It was found that 3-alkylbenzoxazolinones and 2-alkylthiobenzoxazoles exhibited fungicidal activity against the pathogen, Fugarium oxyporum and Verticillum dahlia. Among them, 2-methylthiobenzoxazole inhibited spores of the fungi Verticillum dahlia by 96.4% and benzoxazolyl-2-carbamic acid butyl ester by 65%. These compounds exhibit fungicidal action against the pathogens of powdery mildew on cucumbers - Erysiphe cichoraceorum and powdery mildew on wheat - Erysiphe graminis, approaching the control Karatan. Apparently, these compounds are chemicals of contact action.

Chemisorption of CO2 on diaminated silica as bicarbonates and different types of carbamate ammonium ion pairs

Direct excitation and {1H}13C-CPMAS NMR allowed detecting carbamate–ammonium ion pairs, carbamic acid and bicarbonate species in amine-modified silica sorbents.

Identifikasi Senyawa Ekstraktif Kayu Cendana Papua dan Potensinya Sebagai Pengusir Nyamuk

Penelitian ini bertujuan untuk mengidentifikasi komponen kimia dari kayu cendana Papua (Flindersia sp.) dan menganalisa potensi pemanfaatannya sebagai pengusir nyamuk. Metode eksperimen yang dilakukan adalah analisis fitokimia kualitatif, analisis GCMS Pirolisis, dan uji mortalitas nyamuk untuk menginvestigasi sifat anti-nyamuk dari jenis kayu ini berdasarkan SNI 06-3566-1994. Hasil analisis fitokimia menunjukkan adanya komponen fitokimia seperti alkaloid, saponin, flavonoid, terpenoid, glikosida dan fenolik. Analisis GCMS pirolisis mengindikasikan bahwa diantara 43 senyawa kimia, butylated hydroxyanisole (5,37%), carbamic acid (5,30%), 2,4 imidazolidinedione (2,13%) and hydrazin (1,23%) adalah senyawa yang berperan dalam mengusir nyamuk. Uji mortalitas nyamuk menggunakan sampel uji dengan komposisi serbuk cendana Papua dan tempurung kelapa sebesar 50:50 menunjukkan tingkat kematian nyamuk tertinggi (55,6%). Hal ini mengindikasikan bahwa jenis kayu ini berpotensi untuk dijadikan sebagai bahan kimia alami pengusir nyamuk.

Radiolysis of NH3:CO ice mixtures – implications for Solar system and interstellar ices

ABSTRACT Experimental results on the processing of NH3:CO ice mixtures of astrophysical relevance by energetic (538 MeV 64Ni24+) projectiles are presented. NH3 and CO are two molecules relatively common in interstellar medium and Solar system; they may be precursors of amino acids. 64Ni ions may be considered as representative of heavy cosmic ray analogues. Laboratory data were collected using mid-infrared Fourier transform spectroscopy and revealed the formation of ammonium cation (NH$_4^+$), cyanate (OCN−), molecular nitrogen (N2), and CO2. Tentative assignments of carbamic acid (NH2COOH), formate ion (HCOO−), zwitterionic glycine (NH$_3^+$CH2COO−), and ammonium carbamate (NH$_4^+$NH2COO−) are proposed. Despite the confirmation on the synthesis of several complex species bearing C, H, O, and N atoms, no N–O-bearing species was detected. Moreover, parameters relevant for computational astrophysics, such as destruction and formation cross-sections, are determined for the precursor and the main detected species. Those values scale with the electronic stopping power (Se) roughly as σ ∼ a S$_\mathrm{ e}^n$, where n ∼ 3/2. The power law is helpful for predicting the CO and NH3 dissociation and CO2 formation cross-sections for other ions and energies; these predictions allow estimating the effects of the entire cosmic ray radiation field.

Conversion of Isocyanide to Amine in The Presence of Water and Hg(II) Ions: Kinetics and Mechanism as Detected by Fluorescence Spectroscopy and Mass Spectrometry

Aromatic isocyanides including isocyanonaphthalene derivatives have been proven to be very effective fluorescent sensors for the quantification of Hg(II) ions in water. Thus, the reaction of 1,5-isocyanoaminonaphthalene (1,5-ICAN), which is one of the most important members of this family, with water and HgCl2 as the oxidation agents, was studied by fluorescence spectroscopy and mass spectrometry in order to get deeper insight into the kinetics and mechanistic details of this complex reaction. The reactions of 1,5-ICAN with water and HgCl2 were performed in various water/co-solvent mixtures of different compositions. The co-solvents used in this study were both aprotic solvents including tetrahydrofuran, acetonitrile and N,N-dimethylformamide and protic solvents, such as ethanol and 2-propanol. It was found that in aprotic solvents the conversion of the isocyano group to amino moiety takes place, while in protic solvents the corresponding carbamate (urethane) group is formed in addition to the amino moiety. The variation of the resulting fluorescence intensities versus time curves were described using an irreversible, consecutive reaction model, in which the formation of isocyanate and carbamic acid intermediates, as well as diamino and carbamate (in the case of protic solvents) products were assumed. The formation of these intermediates and products was unambiguously confirmed by mass spectrometric measurements. Furthermore, by fitting the model to the experimental fluorescence versus time curves, the corresponding rate coefficients were determined. It was observed that the overall rate of transformation of the isocyano group to amino moiety increased with the water concentration and the polarity of the co-solvent. It was also supported that formation of diamino and carbamate derivatives in protic solvents takes place simultaneously and that the ratio of the amino to the carbamate function increased with the increasing water concentration. In addition, with an extension, the model presented herein proved to be capable of describing the kinetics of the transformation of 1,5-diisocyanonaphthalene (1,5-DIN) into 1,5-diaminonaphthalene (1,5-DAN) in the mixtures of water/aprotic solvents.