New class of cocogem surfactants based on hexamethylenediamine, propylene oxide, and long chain carboxylic acids: Theory and application

Elgun E. Hasanov,Ravan A. Rahimov,Yusif Abdullayev,Ziyafaddin H. Asadov,Gulnara A. Ahmadova,Aygun M. Isayeva,Saida F. Ahmadbayova,Fedor I. Zubkov,Jochen Autschbach 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.86 No.-

Six cocogem surfactants were synthesized from N,N,Nʹ,Nʹ-tetra-(propane-2-olyl)-1,6-hexanediamine andhigher monocarboxylic acids: capric, lauric, myristic, palmitic, stearic and oleic. N,N,Nʹ,Nʹ-tetra-(propane-2-olyl)-1,6-hexanediamine was synthesized from hexamethylenediamine and propylene oxide at roomtemperature, without utilizing any catalyst or solvent. Surface tension, conductivity, foaming ability,foam stability, emulsion stability, viscosity and density measurements were performed on aqueoussolutions of all cocogem surfactants. Their surface activity and colloidal-chemical parameters such ascritical micelle concentration (CMC), surface pressure at CMC (pCMC), surface tension at CMC (gCMC),surface excess (Gmax), concentration required for 20 mN/m reduction of surface tension (C20), Gibbsenergies of adsorption and micellization (DGad and DGmic) were recorded and variation of theseparameters based on hydrophobic chain length and structure was investigated experimentally andcomputationally. Synthesized surfactants with myristic, palmitic, and stearic tail continued to decreasesurface tension even above CMC. The possible reason of this unusual behavior was determined based oncomputational studies. Surface activity parameters of cocogem surfactant with oleic tail disobeyed thegeneral tendency established by other cocogems with saturated tail group. Palmitic and stearic acid basedcocogem surfactants had good foam stability and the reason of this high foam stability was rationalizedwith high viscosity of their solutions.

Formation of Color Centers and Concentration of Defects in Boron Carbide Irradiated at Low Gamma Radiation Doses

Matlab Nabi Mirzayev,Ravan Nadir Mehdiyeva,Sevinj Zellabdin Melikova,Sakin Hamid Jabarov,Thabsile Theodora Thabethe,Saphina Biira,Mirze Abdulla Kurbanov,Nguyen Van Tiep 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.4

In the present work, boron-carbide (B4C) samples (purity of 99.5% and density of 1.80 g/cm3) were irradiated by using gamma radiation from a 60Co gamma source. Gamma irradiation of the samples was carried out at doses 48.5, 97, 145.5 and 194 kGy. The samples were analysed using a UV-V Gary 50 Scan spectrophotometer. The eect of dierent irradiation doses on the defects created in the B4C samples was investigated. In the B4C samples, the formation processes for color centers depended on the gamma irradiation dose. The calculated activation energies at room temperature essential for the formation of F and F+ color centers ranged from 1.89 - 2.05 eV.

CO₂ Transport, Variability, and Budget over the Southern California Air Basin Using the High-Resolution WRF-VPRM Model during the CalNex 2010 Campaign

Park, Changhyoun,Gerbig, Christoph,Newman, Sally,Ahmadov, Ravan,Feng, Sha,Gurney, Kevin R.,Carmichael, Gregory R.,Park, Soon-Young,Lee, Hwa-Woon,Goulden, Mike AMERICAN METEOROLOGICAL SOCIETY 2018 JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY Vol.57 No.6

<P>To study regional-scale carbon dioxide (CO2) transport, temporal variability, and budget over the Southern California Air Basin (SoCAB) during the California Research at the Nexus of Air Quality and Climate Change (CalNex) 2010 campaign period, a model that couples the Weather Research and Forecasting (WRF) Model with the Vegetation Photosynthesis and Respiration Model (VPRM) has been used. Our numerical simulations use anthropogenic CO2 emissions of the Hestia Project 2010 fossil-fuel CO2 emissions data products along with optimized VPRM parameters at 'FLUXNET'' sites, for biospheric CO2 fluxes over SoCAB. The simulated meteorological conditions have been validated with ground and aircraft observations, as well as with background CO2 concentrations from the coastal Palos Verdes site. The model captures the temporal pattern of CO2 concentrations at the ground site at the California Institute of Technology in Pasadena, but it overestimates the magnitude in early daytime. Analysis of CO2 by wind directions reveals the overestimate is due to advection from the south and southwest, where downtown Los Angeles is located. The model also captures the vertical profile of CO2 concentrations along with the flight tracks. The optimized VPRM parameters have significantly improved simulated net ecosystem exchange at each vegetation-class site and thus the regional CO2 budget. The total biospheric contribution ranges approximately from -24% to -20% (daytime) of the total anthropogenic CO2 emissions during the study period.</P>

Colloidal-Chemical Parameters of Petroleum-collecting and Dispersing Surfactants Based on Vegetable Oil Acid Fractions and 2-(Chloromethyl) Oxirane

Asadov, Ziyafaddin H.,Ahmadova, Gulnara A.,Rahimov, Ravan A.,Mammadova, Khuraman A. Korean Chemical Society 2011 대한화학회지 Vol.55 No.6

Novel surfactants have been synthesized by catalytic chloropropoxylation reaction of carboxylic acid fractions of sunflower, olive, cottonseed, soya-bean, castor and corn oils with 2-(chloromethyl)oxirane. Colloidal-chemical parameters as well as petroleum-collecting and petroleum-dispersing capacities of the synthesized chloropropoxylate esters having heterochain of various lengths have been determined. Influence of carboxylic acid fractions composition and length of chloroxypropylene chain on petroleum-collecting and dispersing capacities has been revealed.

Sunn pest, Eurygaster integriceps Putton (Hemiptera: Scutelleridae), digestive α-amylase, α-glucosidase and β-glucosidase

Mohammad Mehrabadi,Fatemeh Saadati,Sultan Ravan,Ali R. Bandani 한국응용곤충학회 2009 Journal of Asia-Pacific Entomology Vol.12 No.2

Morphology, pH and carbohydrate hydrolyzing enzyme activities of the Sunn pest gut were investigated in this study. The Sunn pest midgut is separated into the first ventriculus (V1), the second ventriculus (V2), the third ventriculus (V3) and the fourth ventriculus (V4). The first three regions of the midgut were acidic (pH 5.0–5.2), while the fourth region of the midgut and rectum was moderately acidic (pH 6.2–6.4 and pH 6.5–6.8, respectively). Activity of α-amylase was highest at pH 6 to 7, which correlates with the pH of the midgut. The optimum pH for α-glucosidase and β-glucosidase is 4 to 6 and 5 to 6, respectively. Different gut regions had different carbohydrate hydrolyzing enzyme activities. Carbohydrate hydrolyzing enzyme activities in V2 and V4were the same, but activities in V1 were slightly higher than in V2 and V4 and lower than in V3. Levels of α- and β-glucosidase activities were similar in various midgut sections. However, the V3 had the highest activity followed by V4, V2, V1, respectively. Morphology, pH and carbohydrate hydrolyzing enzyme activities of the Sunn pest gut were investigated in this study. The Sunn pest midgut is separated into the first ventriculus (V1), the second ventriculus (V2), the third ventriculus (V3) and the fourth ventriculus (V4). The first three regions of the midgut were acidic (pH 5.0–5.2), while the fourth region of the midgut and rectum was moderately acidic (pH 6.2–6.4 and pH 6.5–6.8, respectively). Activity of α-amylase was highest at pH 6 to 7, which correlates with the pH of the midgut. The optimum pH for α-glucosidase and β-glucosidase is 4 to 6 and 5 to 6, respectively. Different gut regions had different carbohydrate hydrolyzing enzyme activities. Carbohydrate hydrolyzing enzyme activities in V2 and V4were the same, but activities in V1 were slightly higher than in V2 and V4 and lower than in V3. Levels of α- and β-glucosidase activities were similar in various midgut sections. However, the V3 had the highest activity followed by V4, V2, V1, respectively.

Saccharification of Brown Macroalgae Using an Arsenal of Recombinant Alginate Lyases: Potential Application in the Biorefinery Process

( Javier A. Gimpel ),( Maria Cristina Ravanal ),( Oriana Salazar ),( Maria Elena Lienqueo ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.10

Alginate lyases (endo and exo-lyases) are required for the degradation of alginate into its constituting monomers. Efficient bioethanol production and extraction of bioactives from brown algae requires intensive use of these enzymes. Nonetheless, there are few commercial alginate lyase preparations, and their costs make them unsuitable for large scale experiments. A recombinant expression protocol has been developed in this study for producing seven endo-lyases and three exo-lyases as soluble and highly active preparations. Saccharification of alginate using 21 different endo/exo-lyase combinations shows that there is complementary enzymatic activity between some of the endo/exo pairs. This is probably due to favorable matching of their substrate biases for the different glycosidic bonds in the alginate molecule. Therefore, selection of enzymes for the best saccharification results for a given biomass should be based on screens comprising both types of lyases. Additionally, different incubation temperatures, enzyme load ratios, and enzyme loading strategies were assessed using the best four enzyme combinations for treating Macrocystis pyrifera biomass. It was shown that 30°C with a 1:3 endo/exo loading ratio was suitable for all four combinations. Moreover, simultaneous loading of endo-and exo-lyases at the beginning of the reaction allowed maximum alginate saccharification in half the time than when the exo-lyases were added sequentially.

Study of blend composition of nano silica under the influence of neutron flux

Huseynov Elchin,Garibov Adil,Mehdiyeva Ravan 나노기술연구협의회 2014 Nano Convergence Vol.1 No.21

Nano SiO2 compound with 160 m2/g specific surface area and 20 nm sizes has been irradiated continuously with neutron flux up to 20 hours in various periods in TRIGA Mark II type research reactor. The initial activities of different type radionuclides defined in the result of eight day activity analysis changes between wide range of 1,5 kBq- 1,5GBq. In the result of activity analysis carried out after the irradiation, the element content of 0,5% mixture existing in nano SiO2 compound has been defined with radionuclides of relevant element. It has been defined percentage amounts of elements in blend composition according to the performed activities.

Antiglycation and antioxidant activity of four Iranian medical plant extracts

Safari, Mohammad Reza,Azizi, Omid,Heidary, Somayeh Sadat,Kheiripour, Nejat,Ravan, Alireza Pouyandeh KOREAN PHARMACOPUNCTURE INSTITUTE 2018 Journal of pharmacopuncture Vol.21 No.2

Objective: Diabetes mellitus (DM) is the most common metabolic disorder that defined by chronic hyperglycemia for the deficiency in insulin secretion or resistance. Hyperglycemia could induce non-enzymatic glycation of proteins. It has been suggested that some traditional plants can improve blood glucose and inhibit glycation process. This work evaluates and compares the anti-glycation activities of four Iranian plant extracts in vitro. Methods: The methanolic extract of "Fumaria officinalis, Stachys lavandulifolia, Salvia hydrangea and Rosa Damascene" was prepared in three different concentrations. Phenolic, flavonoids content and antioxidant activity were evaluated. The multistage glycation markers- fructosamines (early stage), protein carbonyls (intermediate stage) and ${\beta}$ aggregation of albumin were investigated in the bovine serum albumin (BSA)/ glucose systemt. Results: All plants showed the high potency of scavenging free radicals and glycation inhibition in the following order: Fumaria officinalis> Rosa Damascene> Stachys lavandulifolia > Salvia hydrangea. There was a significant correlation between antioxidant and anti-glycation activity. Also, the antioxidant and anti-glycation capacity of extracts correlated with total phenolic and flavonoids content. Conclusion: Our findings demonstrated that the studied plants are good sources of anti-glycation and antioxidant compounds and, these properties can primarily attributable to phenolics, particularly flavonoids.

Synthesis of graphitic carbon from Pisum sativum for supercapacitor applications

Sushilkumar A. Jadhav,Pranoti H. Patil,Suchitra B. Ravan,Saurabh S. Thoravat,Tukaram D. Dongale 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.9

This work reports preparation of Pisum sativum (peas) derived graphitic carbon (PSC) and its activation with potassium hydroxide (KOH), referred to as Pisum sativum derived activated graphitic carbon (PSAC). The structure, morphology and surface area of the materials were characterized by using X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Raman spectroscopy and Brunauer Emmet Teller (BET). The electrochemical performance of the material was investigated by using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), cyclic stability and electrochemical impedance spectroscopy (EIS). The graphitic carbon obtained showed specific surface area of 240 m2 g−1 with pore size of 3.32nm. The electrochemical testing of activated carbon delivered specific capacitance of 517 F g−1 at 10 mV s−1 with 86% of capacitance retention after 2,000 cycles at 10 mA cm−2. It showed high specific energy of 35 Wh kg−1 at specific power 645 W kg−1.

Antiglycation and antioxidant activity of four Iranian medical plant extracts

Mohammad Reza Safari,Omid Azizi,Somayeh Sadat Heidary,Nejat Kheiripour,Alireza Pouyandeh Ravan 대한약침학회 2018 Journal of pharmacopuncture Vol.21 No.2

Objective: Diabetes mellitus (DM) is the most common metabolic disorder that defined by chronic hyperglycemia for the deficiency in insulin secretion or resistance. Hyperglycemia could induce non-enzymatic glycation of proteins. It has been suggested that some traditional plants can improve blood glucose and inhibit glycation process. This work evaluates and compares the anti-glycation activities of four Iranian plant extracts in vitro. Methods: The methanolic extract of “Fumaria officinalis, Stachys lavandulifolia, Salvia hydrangea and Rosa Damascene” was prepared in three different concentrations. Phenolic, flavonoids content and antioxidant activity were evaluated. The multistage glycation markers- fructosamines (early stage), protein carbonyls (intermediate stage) and β aggregation of albumin were investigated in the bovine serum albumin (BSA)/ glucose systemt. Results: All plants showed the high potency of scavenging free radicals and glycation inhibition in the following order: Fumaria officinalis> Rosa Damascene> Stachys lavandulifolia > Salvia hydrangea. There was a significant correlation between antioxidant and anti-glycation activity. Also, the antioxidant and anti-glycation capacity of extracts correlated with total phenolic and flavonoids content. Conclusion: Our findings demonstrated that the studied plants are good sources of anti-glycation and antioxidant compounds and, these properties can primarily attributable to phenolics, particularly flavonoids.