Статті в журналах з теми "Synthetic natural ga"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Synthetic natural ga.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 статей у журналах для дослідження на тему "Synthetic natural ga".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте статті в журналах для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Song, Hyunwook, Seungik Jeon, Yerim Shin, Woojae Han, Saea Kim, Chanbeom Kwak, Eunsung Lee, and Jinsook Kim. "Effects of Natural Versus Synthetic Consonant and Vowel Stimuli on Cortical Auditory-Evoked Potential." Journal of Audiology and Otology 26, no. 2 (April 10, 2022): 68–75. http://dx.doi.org/10.7874/jao.2021.00479.
Повний текст джерелаАнотація:
Background and Objectives: Natural and synthetic speech signals effectively stimulate cortical auditory evoked potential (CAEP). This study aimed to select the speech materials for CAEP and identify CAEP waveforms according to gender of speaker (GS) and gender of listener (GL).Subjects and Methods: Two experiments including a comparison of natural and synthetic stimuli and CAEP measurement were performed of 21 young announcers and 40 young adults. Plosive /g/ and /b/ and aspirated plosive /k/ and /p/ were combined to /a/. Six bisyllables–/ga/-/ka/, /ga/-/ba/, /ga/-/pa/, /ka/-/ba/, /ka/-/pa/, and /ba/-/pa/–were formulated as tentative forwarding and backwarding orders. In the natural and synthetic stimulation mode (SM) according to GS, /ka/ and /pa/ were selected through the first experiment used for CAEP measurement.Results: The correction rate differences were largest (74%) at /ka/-/ pa/ and /pa/-/ka/; thus, they were selected as stimulation materals for CAEP measurement. The SM showed shorter latency with P2 and N1-P2 with natural stimulation and N2 with synthetic stimulation. The P2 amplitude was larger with natural stimulation. The SD showed significantly larger amplitude for P2 and N1-P2 with /pa/. The GS showed shorter latency for P2, N2, and N1-P2 and larger amplitude for N2 with female speakers. The GL showed shorter latency for N2 and N1-P2 and larger amplitude for N2 with female listeners.Conclusions: Although several variables showed significance for N2, P2, and N1-P2, P1 and N1 did not show any significance for any variables. N2 and P2 of CAEP seemed affected by endogenous factors.
2
Kloprogge, J. Theo, and Concepcion P. Ponce. "Spectroscopic Studies of Synthetic and Natural Saponites: A Review." Minerals 11, no. 2 (January 23, 2021): 112. http://dx.doi.org/10.3390/min11020112.
Повний текст джерелаАнотація:
Saponite is a trioctahedral 2:1 smectite with the ideal composition MxMg3AlxSi4−xO10(OH,F)2.nH2O (M = interlayer cation). Both the success of the saponite synthesis and the determination of its applications depends on robust knowledge of the structure and composition of saponite. Among the routine characterization techniques, spectroscopic methods are the most common. This review, thus, provides an overview of various spectroscopic methods to characterize natural and synthetic saponites with focus on the extensive work by one of the authors (JTK). The Infrared (IR) and Raman spectra of natural and synthetic saponites are discussed in detail including the assignment of the observed bands. The crystallization of saponite is discussed based on the changes in the IR and Raman spectra and a possible crystallization model is provided. Infrared emission spectroscopy has been used to study the thermal changes of saponite in situ including the dehydration and (partial) dehydroxylation up to 750 °C. 27Al and 29Si magic-angle-spinning nuclear magnetic resonance spectroscopy is discussed (as well as 11B and 71Ga for B- and Ga-Si substitution) with respect to, in particular, Al(IV)/Al(VI) and Si/Al(IV) ratios. X-ray photoelectron spectroscopy provides chemical information as well as some information related to the local environments of the different elements in the saponite structure as reflected by their binding energies.
3
Mallick, Subhashis. "Some practical aspects of prestack waveform inversion using a genetic algorithm: An example from the east Texas Woodbine gas sand." GEOPHYSICS 64, no. 2 (March 1999): 326–36. http://dx.doi.org/10.1190/1.1444538.
Повний текст джерелаАнотація:
In this paper, a prestack inversion method using a genetic algorithm (GA) is presented, and issues relating to the implementation of prestack GA inversion in practice are discussed. GA is a Monte‐Carlo type inversion, using a natural analogy to the biological evolution process. When GA is cast into a Bayesian framework, a priori information of the model parameters and the physics of the forward problem are used to compute synthetic data. These synthetic data can then be matched with observations to obtain approximate estimates of the marginal a posteriori probability density (PPD) functions in the model space. Plots of these PPD functions allow an interpreter to choose models which best describe the specific geologic setting and lead to an accurate prediction of seismic lithology. Poststack inversion and prestack GA inversion were applied to a Woodbine gas sand data set from East Texas. A comparison of prestack inversion with poststack inversion demonstrates that prestack inversion shows detailed stratigraphic features of the subsurface which are not visible on the poststack inversion.
4
Mayadewi, Ni Nyoman Ari, and Nyoman Gede Astawa. "QUALITY ENHANCEMENT OF TOMATOES (Lycopersicum esculentum Mill.) USING GIBBERELLIC ACID (GA) FROM VARIOUS PLANT MATERIALS." International Journal of Biosciences and Biotechnology 9, no. 1 (January 26, 2022): 60. http://dx.doi.org/10.24843/ijbb.2021.v09.i01.p07.
Повний текст джерелаАнотація:
Tomato (Lycopersicum esculentum Mill.) is a fruit with many benefits. Plant growth regulators (PGRs) prove effective in improving the quality and production of tomatoes. Gibberellic Acid/GA is a PGR that stimulates the process of flowering, parthenocarpy, and carbohydrate mobilization during germination and influences other plant physiological aspects. However, because synthetic GA is costly, numerous natural ingredients have been proposed as its source, for example, bamboo shoots, vegetable ferns, corns, and shallots that can improve the quality of tomatoes. This study aimed to determine the role of natural GA from various plant extracts on the quality of tomatoes, providing recommendations for the best extract to improve the quality of tomatoes. It was conducted in the experimental garden at the Agronomy and Horticulture Laboratory, Physiology Laboratory of the Faculty of Agriculture, and Food Analysis Laboratory of the Faculty of Agricultural Technology, Udayana University. This research was compiled using a Randomized Group Design consisting of one factor, i.e., the type of natural extract with five settings and four repetitions. The tomato plant treatments were E0 = no extract sprayed, BE = sprayed with bamboo shoot extract, VE = vegetable fern extract, OE = onion extract, and CE = corn extract. The results showed that gibberellins from natural ingredients significantly affected fruit diameter, fruit thickness, and total sugar content of tomatoes. The best tomatoes were obtained by applying onion extract as a source of natural gibberellins.
5
Maharani, Nia. "PEMODELAN INVERSI DATA MAGNETOTELLURIK 1-D MENGGUNAKAN METODA GENETIC ALGORITHM (GA) DENGAN POPULASI MICRO GENETIC ALGORITHM KASUS 3 LAYER DAN 5 LAYER." Jurnal Santiaji Pendidikan (JSP) 8, no. 2 (January 10, 2019): 167–80. http://dx.doi.org/10.36733/jsp.v8i2.175.
Повний текст джерелаАнотація:
This paper discusses non-linear inversion method with Genetic Algorithm (GA) which inspired by natural selection process (survival for the fittest) and genetic using 20 populations (micro genetic algorithm). The method is applied to 1-D magnetotelluric inverted data with model parameter is resistivity as a function of depth. This research only uses synthetic data obtained from synthetic model. The model is homogeneous earth model with 3 and 5 layers. Perturbation of model is performed until minimum misfit between theoritical and observation data achieved. The 3 layers and 5 layers inversion processes are applied to 3 layers and 5 layers earth model respectively, with satisfactory results in other words it can reproduce the synthetic model.
6
Semyonov, M. E., L. P. Kalacheva, and E. Y. Shits. "Studying of features of processes of formation and mechano-chemical processing synthetic hydrates of natural ga." "Proceedings" of "OilGasScientificResearchProjects" Institute, SOCAR, no. 4 (December 30, 2014): 40–45. http://dx.doi.org/10.5510/ogp20140400220.
Повний текст джерела
7
Tyagi, Rekha, Surjeet Verma, Shikha Mishra, Mrigank Srivastava, Sarfaraz Alam, Feroz Khan, and Santosh Kumar Srivastava. "In Vitro and In Silico Studies of Glycyrrhetinic Acid Derivatives as Anti- Filarial Agents." Current Topics in Medicinal Chemistry 19, no. 14 (August 28, 2019): 1191–200. http://dx.doi.org/10.2174/1568026619666190618141450.
Повний текст джерелаАнотація:
Background: Lymphatic filariasis is one of the chronic diseases in many parts of the tropics and sub-tropics of the world despite the use of standard drugs diethylcarbamazine and ivermectin because they kill microfilaries and not the adult parasites. Therefore, new leads with activity on adult parasites are highly desirable. Objective: Anti-filarial lead optimization by semi-synthetic modification of glycyrrhetinic acid (GA). Methods: The GA was first converted into 3-O-acyl derivative, which was further converted into 12 amide derivatives. All these derivatives were assessed for their antifilarial potential by parasite motility assay. The binding affinity of active GA derivatives on trehalose-6-phosphate phosphatase (Bm-TPP) was assessed by molecular docking studies. Results: Among 15 GA derivatives, GAD-2, GAD-3, and GAD-4 were found more potent than the GA and standard drug DEC. These derivatives reduced the motility of Brugia malayi adult worms by up to 74% while the GA and DEC reduced only up to 49%. Further, GA and most of its derivatives exhibited two times more reduction in MTT assay when compared to the standard drug DEC. These derivatives also showed 100% reduction of microfilariae and good interactions with Bm-TPP protein. Conclusion: The present study suggests that 3-O-acyl and linear chain amide derivatives of glycyrrhetinic acid may be potent leads against B. malayi microfilariae and adult worms. These results might be helpful in developing QSAR model for optimizing a new class of antifilarial lead from a very common, inexpensive, and non toxic natural product.
8
Omoruyi, Jeffrey I., George E. Eriyamremu, Israel E. Ebhohimen, Oke A. Emuedo, and Edwina O. Uzunuigbe. "The Effect of Aqueous Extract of Gum Arabic on Hepato-renal Function During Ethanol Withdrawal Induced Stress in Wistar Rats." Avicenna Journal of Medical Biochemistry 10, no. 2 (December 4, 2022): 135–41. http://dx.doi.org/10.34172/ajmb.2022.2363.
Повний текст джерелаАнотація:
Background: Alcohol withdrawal syndrome (AWS) is a life-threatening condition affecting alcoholics who ceased or decreased their alcohol consumption. The synthetic drugs used to manage these consequences are not without undesirable effects; hence, the need for a natural and affordable approach is raised. Objectives: This study aimed at investigating the effect of aqueous extract of gum arabic (GA) on hepato-renal functions during ethanol withdrawal syndrome in Wistar rats. Methods: In phase I, dose-response for GA and alcohol for the study were determined. In phase II, the effect of GA on biomarkers during AWS was studied. A total of 60 male Wistar rats were used for the study. Blood and tissue samples were obtained at the end of stipulated periods of oral administration for biochemical and histological analysis, and biochemical parameters were analyzed by spectrophotometry. Results: In the dose-response study, there were no significant differences (P≥0.05) in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities as well as in total bilirubin (TBIL), malondialdehyde (MDA), sodium ion (Na+), potassium ion (K+), and creatinine concentrations in groups treated with 200 mg/kg body weight (bw) and 400 mg/kg bw GA aqueous extract compared to the control group. However, significant alterations were observed in groups treated with 600 and 800 mg/kg bw GA extract. Furthermore, rats that received 5.5 mL/kg bw alcohol showed marked changes in biochemical parameters compared to the group that received 4.5 mL/kg bw and the control group. The results obtained in Phase II exhibited the hepato-renal protective effect of GA during ethanol withdrawal. Statistical analysis of the obtained results indicated a better response from the study groups that were pre-treated or co-administered with GA compared to the group that was post-treated. Conclusion: The result of this study suggests that GA aqueous extract offered better protection prophylactically than curatively.
9
Walden, Brian E., Allen A. Montgomery, Robert A. Prosek, and David B. Hawkins. "Visual Biasing of Normal and Impaired Auditory Speech Perception." Journal of Speech, Language, and Hearing Research 33, no. 1 (March 1990): 163–73. http://dx.doi.org/10.1044/jshr.3301.163.
Повний текст джерелаАнотація:
Intersensory biasing occurs when cues in one sensory modality influence the perception of discrepant cues in another modality. Visual biasing of auditory stop consonant perception was examined in two related experiments in an attempt to clarify the role of hearing impairment on susceptibility to visual biasing of auditory speech perception. Fourteen computer-generated acoustic approximations of consonant-vowel syllables forming a /ba-da-ga/ continuum were presented for labeling as one of the three exemplars, via audition alone and in synchrony with natural visual articulations of /ba/ and of /ga/. Labeling functions were generated for each test condition showing the percentage of /ba/, /da/, and /ga/ responses to each of the 14 synthetic syllables. The subjects of the first experiment were 15 normal-hearing and 15 hearing-impaired observers. The hearing-impaired subjects demonstrated a greater susceptibility to biasing from visual cues than did the normal-hearing subjects. In the second experiment, the auditory stimuli were presented in a low-level background noise to 15 normal-hearing observers. A comparison of their labeling responses with those from the first experiment suggested that hearing-impaired persons may develop a propensity to rely on visual cues as a result of long-term hearing impairment. The results are discussed in terms of theories of intersensory bias.
10
Ayvaz, Melek Col. "Antioxidant activity of Trachystemon orientalis (L.) G. Don (Borage) grown and eaten as food in Ordu, Turkey." Herba Polonica 61, no. 4 (December 1, 2015): 40–51. http://dx.doi.org/10.1515/hepo-2015-0030.
Повний текст джерелаАнотація:
SummaryIntroductıon: Instead of synthetic antioxidants, using of natural products with antioxidant activity is demanded.Objectıve: The aim of this study is to evaluate the antioxidant activity and total phenolic and flavonoid contents of theTrachystemon orientalis(borage) obtained from Ordu.Methods: The water and ethanol extracts of the borage plant were investigated by using severalin vitroantioxidant activity tests such as total antioxidant capacity, O2•−,•OH, DPPH and ABTS radicals scavenging activities, hydrogen peroxide scavenging activity, FRAP, Fe2+chelating and reducing power assays in order to make effective comparisons.Results: Water extract of theT. orientalishad the more phenolic (90 mg GA/g extract) and flavonoid (56.88 mg CT/g extract) contents than ethanol extract. Furthermore, both of the extracts showed strong antioxidant and radical scavenging activities determined by differentin vitromodels. The highest total antioxidant capacity as ascorbic acid equivalents of 244.50 mg/g extract was also calculated for water extract. Generally, a relationship between total phenolic content and antioxidant activity was established. It is also an important finding for an edible food source that the phenolic and flavonoid content and antioxidative activities for water extract was higher than the ethanol extract.Conclusıon:T. orientaliscould be used as a food ingredient instead of synthetic antioxidants and all results will contribute to the recent increase in investigations on using natural products in many areas such as food, pharmacy, alternative medicine and natural therapy.
11
ayan, Larny Mary J., S. Karthikeyan, D. Joice Sheeba, G. R. Angel, E. V. Kripa, S. Madeswaran, and A. Stephen. "Synthesis and Characterization of Polyvinyl Alcohol-Gum Arabic Polymer Blend Membranes." Asian Journal of Chemistry 32, no. 1 (November 18, 2019): 111–14. http://dx.doi.org/10.14233/ajchem.2020.22325.
Повний текст джерелаАнотація:
Membranes of poly(vinyl alcohol) (PVA), gum arabic (GA) homopolymer and their blends of six different compositions (w/w) were prepared using solution casting method. Mixing of synthetic polymer e.g., PVA and natural polymer e.g., gum arabic can give a new class of polymer blend with better mechanical properties and biocompatibility than those of single components. The structural, optical and conductivity studies of these prepared membranes were examined by XRD, FTIR, UV and EIS. The XRD diffraction patterns for the polymer blend samples showed that they are more amorphous in nature as compared to pure PVA and pure gum arabic. The FTIR analysis of the samples gave information about various functional groups present in the samples. The energy band gap of various samples were obtained from UV-visible analysis. The conductivity of polymer membrane was analyzed by electronics impedance spectroscopy (EIS). Addition of natural polymer gum arabic has resulted slight increase in the conductivity of blend polymer.
12
Al-Awaji, Noha, Moufida Boukriba, Abuzar Albadri, Mohamed Ali Ben Aissa, Mohamed Bououdina, and Abueliz Modwi. "Green Ca-Loaded MgO Nanoparticles as an Efficient Adsorbent for Organic Hazardous Dyes." Journal of Nanomaterials 2022 (September 2, 2022): 1–16. http://dx.doi.org/10.1155/2022/5062752.
Повний текст джерелаАнотація:
Textile industry wastewater is a principal source of environmental contamination, posing serious health and environmental risks; consequently, appropriate treatments are necessary before ultimate discharge to ensure environmental and public health safety. In this study, 10% Ca-doped MgO (Ca0.10Mg0.90O) has been prepared via a green and ecologically benign approach using aqueous solution of gum arabic (GA) and then used to eliminate Congo red (CR) from aqueous solution. The XRD analysis reveals a size reduction of MgO nanoparticles from 11 to 6 nm after doping with a surface area reaching 50.1 m2·g-1 for the synthesized heterostructure. An excellent adsorption efficiency of 97% has been achieved under the following optimal operational conditions, i.e., adsorbent dosage of Ca0.10Mg0.90O (0.400 g/L), contact time of 120 min, and solution pH of 7.00. As indicated by pH, isotherm, and FTIR examinations, the CR sorption process is related to chemisorption and hydrogen bonding. The findings indicate that the synthesized nanomaterial is a suitable candidate for dyes containing effluent treatment due to its facile green synthetic approach using a natural product GA, low-cost, mesoporous nature, and high uptake capacity under neutral solution pH.
13
Peggion, C., V. Moretto, F. Formaggio, M. Crisma, C. Toniolo, J. Kamphuis, B. Kaptein та Q. B. Broxterman. "Partial [αMe]Aun scan of [l -Leu11 -OMe]-trichogin GA IV, a membrane active synthetic precursor of the natural lipopeptaibol". Journal of Peptide Research 58, № 4 (жовтень 2001): 317–24. http://dx.doi.org/10.1034/j.1399-3011.2001.00919.x.
Повний текст джерела
14
Mosina, Marika, Claudia Siverino, Liga Stipniece, Artemijs Sceglovs, Renats Vasiljevs, T. Fintan Moriarty, and Janis Locs. "Gallium-Doped Hydroxyapatite Shows Antibacterial Activity against Pseudomonas aeruginosa without Affecting Cell Metabolic Activity." Journal of Functional Biomaterials 14, no. 2 (January 17, 2023): 51. http://dx.doi.org/10.3390/jfb14020051.
Повний текст джерелаАнотація:
Calcium phosphates (CaPs) have been used in bone regeneration for decades. Among the described CaPs, synthetic hydroxyapatite (HAp) has a chemical composition similar to that of natural bone. Gallium-containing compounds have been studied since the 1970s for the treatment of autoimmune diseases and have shown beneficial properties, such as antibacterial activity and inhibition of osteoclast activity. In this study, we synthesized hydroxyapatite (HAp) powder with Ga doping ratios up to 6.9 ± 0.5 wt% using the wet chemical precipitation method. The obtained products were characterized using XRD, BET, FTIR, and ICP-MS. Ga3+ ion release was determined in the cell culture media for up to 30 days. Antibacterial activity was assessed against five bacterial species: Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pyogenes. The biocompatibility of the GaHAp samples was determined in human fibroblasts (hTERT-BJ1) through direct and indirect tests. The structure of the synthesized products was characteristic of HAp, as revealed with XRD and FTIR, although the addition of Ga caused a decrease in the crystallite size. Ga3+ was released from GaHAp paste in a steady manner, with approximately 40% being released within 21 days. GaHAp with the highest gallium contents, 5.5 ± 0.1 wt% and 6.9 ± 0.5 wt%, inhibited the growth of all five bacterial species, with the greatest activity being against Pseudomonas aeruginosa. Biocompatibility assays showed maintained cell viability (~80%) after seven days of indirect exposure to GaHAp. However, when GaHAp with Ga content above 3.3 ± 0.4 wt% was directly applied on the cells, a decrease in metabolic activity was observed on the seventh day. Overall, these results show that GaHAp with Ga content below 3.3 ± 0.4 wt% has attractive antimicrobial properties, without affecting the cell metabolic activity, creating a material that could be used for bone regeneration and prevention of infection.
15
Rojas-Lema, Sandra, Sergio Torres-Giner, Luis Quiles-Carrillo, Jaume Gomez-Caturla, Daniel Garcia-Garcia, and Rafael Balart. "On the Use of Phenolic Compounds Present in Citrus Fruits and Grapes as Natural Antioxidants for Thermo-Compressed Bio-Based High-Density Polyethylene Films." Antioxidants 10, no. 1 (December 25, 2020): 14. http://dx.doi.org/10.3390/antiox10010014.
Повний текст джерелаАнотація:
This study originally explores the use of naringin (NAR), gallic acid (GA), caffeic acid (CA), and quercetin (QUER) as natural antioxidants for bio-based high-density polyethylene (bio-HDPE). These phenolic compounds are present in various citrus fruits and grapes and can remain in their leaves, peels, pulp, and seeds as by-products or wastes after juice processing. Each natural additive was first melt-mixed at 0.8 parts per hundred resin (phr) of bio-HDPE by extrusion and the resultant pellets were shaped into films by thermo-compression. Although all the phenolic compounds colored the bio-HDPE films, their contact transparency was still preserved. The chemical analyses confirmed the successful inclusion of the phenolic compounds in bio-HDPE, though their interaction with the green polyolefin matrix was low. The mechanical performance of the bio-HDPE films was nearly unaffected by the natural compounds, presenting in all cases a ductile behavior. Interestingly, the phenolic compounds successfully increased the thermo-oxidative stability of bio-HDPE, yielding GA and QUER the highest performance. In particular, using these phenolic compounds, the onset oxidation temperature (OOT) value was improved by 43 and 41.5 °C, respectively. Similarly, the oxidation induction time (OIT) value, determined in isothermal conditions at 210 °C, increased from 4.5 min to approximately 109 and 138 min. Furthermore, the onset degradation temperature in air of bio-HDPE, measured for the 5% of mass loss (T5%), was improved by up to 21 °C after the addition of NAR. Moreover, the GA- and CA-containing bio-HDPE films showed a high antioxidant activity in alcoholic solution due to their favored release capacity, which opens up novel opportunities in active food packaging. The improved antioxidant performance of these phenolic compounds was ascribed to the multiple presence of hydroxyl groups and aromatic heterocyclic rings that provide these molecules with the features to permit the delocalization and the scavenging of free radicals. Therefore, the here-tested phenolic compounds, in particular QUER, can represent a sustainable and cost-effective alternative of synthetic antioxidants in polymer and biopolymer formulations, for which safety and environmental issues have been raised over time.
16
Dinparast, Leila, and Siavoush Dastmalchi. "A QSAR Study on the 4-Substituted Coumarins as Potent Tubulin Polymerization Inhibitors." Advanced Pharmaceutical Bulletin 10, no. 2 (February 18, 2020): 271–77. http://dx.doi.org/10.34172/apb.2020.032.
Повний текст джерелаАнотація:
Purpose: Despite the discovery and synthesis of several anticancer drugs, cancer is still a major life threatening incident for human beings after cardiovascular diseases. Toxicity, severe side effects, and drug resistance are serious problems of available commercial anticancer drugs. Coumarins are synthetic and natural heterocycles that show promising antiproliferative activities against various tumors. The aim of this research is to computationally study the coumarin derivatives in order to develop reliable quantitative structure-activity relationship (QSAR) models for predicting their anticancer activities. Methods: A data set of thirty one coumarin analogs with significant antiproliferative activities toward HepG2 cells were selected from the literature. The molecular descriptors for these compounds were calculated using Dragon, HyperChem, and ACD/Labs programs. Genetic algorithm (GA) accompanied by multiple linear regression (MLR) for simultaneous feature selection and model development was employed for generating the QSAR models. Results: Based on the obtained results, the developed linear QSAR models with three and four descriptors showed good predictive power with r2 values of 0.670 and 0.692, respectively. Moreover, the calculated validation parameters for the models confirmed the reliability of the QSAR models. Conclusion: The findings of the current study could be useful for the design and synthesis of novel anticancer drugs based on coumarin structure.
17
Askar, Shavan, Sajjad Zeraat Peyma, Mohanad Mohsen Yousef, Natalia Alekseevna Prodanova, Iskandar Muda, Mohamed Elsahabi, and Javad Hatamiafkoueieh. "Flood Susceptibility Mapping Using Remote Sensing and Integration of Decision Table Classifier and Metaheuristic Algorithms." Water 14, no. 19 (September 28, 2022): 3062. http://dx.doi.org/10.3390/w14193062.
Повний текст джерелаАнотація:
Flooding is one of the most prevalent types of natural catastrophes, and it can cause extensive damage to infrastructure and the natural environment. The primary method of flood risk management is flood susceptibility mapping (FSM), which provides a quantitative assessment of a region’s vulnerability to flooding. The objective of this study is to develop new ensemble models for FSM by integrating metaheuristic algorithms, such as genetic algorithms (GA), particle swarm optimization (PSO), and harmony search (HS), with the decision table classifier (DTB). The proposed algorithms were applied in the province of Sulaymaniyah, Iraq. Sentinel-1 synthetic aperture radar (SAR) data satellite images were used for flood monitoring (on 27 July 2019), and 160 flood occurrence locations were prepared for modeling. For the training and validation datasets, flood occurrence data were coupled to 1 flood-influencing parameters (slope, altitude, aspect, plan curvature, distance from rivers, land cover, geology, topographic wetness index (TWI), stream power index (SPI), rainfall, and normalized difference vegetation index (NDVI)). The certainty factor (CF) approach was used to determine the spatial association between the effective parameters and the occurrence of floods, and the resulting weights were employed as modeling inputs. According to the pairwise consistency technique, the NDVI and altitude are the most significant factors in flood modeling. The area under the receiver operating characteristic (AUROC) curve was used to evaluate the accuracy and effectiveness of ensemble models. The DTB-GA model was found to be the most accurate (AUC = 0.889), followed by the DTB-PSO model (AUC = 0.844) and the DTB-HS model (AUC = 0.812). This research’s hybrid models provide a reliable estimate of flood risk, and the risk maps are reliable for flood early-warning and control systems.
18
Szawarski, Nicolás, Pablo Giménez-Martínez, Giulia Mitton, Pedro Negri, Facundo Meroi Arcerito, María P. Moliné, Sandra Fuselli, Martín Eguaras, Lorenzo Lamattina, and Matías Maggi. "Short communication: Antimicrobial activity of indoleacetic, gibberellic and coumaric acids against Paenibacillus larvae and its toxicity against Apis mellifera." Spanish Journal of Agricultural Research 18, no. 1 (April 22, 2020): e05SC01. http://dx.doi.org/10.5424/sjar/2020181-15158.
Повний текст джерелаАнотація:
Aim of study: To explore three isolated phytomolecules: indoleacetic acid (IAA), gibberellic acid (GA), and the secondary metabolite p-coumaric acid (CUM): (1) evaluating their toxicity against Apis mellifera larvae and adults under controlled conditions in the laboratory; (2) searching for antimicrobial activity against Paenibacillus larvae.Area of study: Honey bee larvae and adults were collected from the experimental apiary of the “Centro de Investigación en Abejas Sociales (CIAS)” (-37.9348798, -57.682817), Institute of the National University of Mar del Plata (UNMdP), Argentina.Material and methods: Paenibacillus larvae strains were isolated from beehives from different provinces of Argentina (Buenos Aires, Córdoba and Entre Ríos) showing clinical symptoms of the American foulbrood. All strains (S1, S2, S3, S4) were genotypically identified using PL5 and PL4 primers and characterized as genotype ERIC1. Then standard essays were performed to determined toxicity of phytomolecules in honey bees and antimicrobial activity through the broth microdilution method.Main results: The diet with GA, IAA and CUM did not present toxic effects in larvae or adult bees, and only CUM showed antimicrobial activity against P. larvae. In this study, we obtained in vitro values of MNIC (minimum non-inhibitory concentration) of 500 μg mL-1 and a MIC (minimum inhibitory concentration) of 650 μg mL-1 for CUM.Research highlights: The obtained results remark its potential as a natural alternative for the control of P. larvae, avoiding the problems generated by the use of synthetic antibiotics such as the resistance phenomena and the contamination of hive’s products.
19
Kariminejad, Mohaddeseh, Abolfazl Naimabadi, Afsaneh Morshedi, Toktam Mohammadi-Moghaddam, Abolfazl Shokuhi, and Mahsa Bordbar. "Oxidative stability of sunflower and soybean oils enriched with black plum peel extract in comparison with synthetic antioxidants." PLOS ONE 18, no. 1 (January 20, 2023): e0279735. http://dx.doi.org/10.1371/journal.pone.0279735.
Повний текст джерелаАнотація:
Black plum peel is the by-product of plum processing and is a valuable source of antioxidants and phenolic compounds. In this research, total phenolic compounds, total flavonoid content and antioxidant activity of black plum peel were measured. After that, black plum peel extract (in concentrations 0, 400, 800, 1200 and 2000 ppm) as a natural antioxidant for improving the stability of soybean and sunflower oil was used. The oxidative stability parameters of oils (peroxide value, free fatty acids, thiobarbituric acid, conjugated dienes, and carbonyl value) were measured at 60 °C for 4–16 days. Antioxidant activity, total phenolic compounds and total flavonoid content of black plum peel were 86.87% and 100.53 mg GA /g and 871.062 mg Quercetin/g respectively. Black plum peel extract could have a significant positive effect (P<0.05) on improvement of the quality and stability parameters of soybean oil and sunflower oil. The oxidative stability parameters for commercial oils and samples containing black plum peel extract were near each other and in an acceptable range. So, black plum peel is recommended as an oxidative stabilizer of oils and alternative synthetic antioxidants.
20
Dong, Yuhan, Peihong Wang, Mengting Jiang, and Shenchun Qu. "Antioxidant and the Dwarfing Candidate Gene of “Nantongxiaofangshi” (Diospyros kaki Thunb.)." Oxidative Medicine and Cellular Longevity 2019 (November 25, 2019): 1–14. http://dx.doi.org/10.1155/2019/1629845.
Повний текст джерелаАнотація:
The aims of this work were to identify genes related to dwarfing for subsequent dwarfing-related research in persimmon and evaluate the relationship between antioxidant activity, dwarf, and hormones of persimmon trees for analyzing the possible dwarf mechanism oxidation factors. In the present study, a transcriptome analysis of “Nantongxiaofangshi” was used to identify and clone 22 candidate genes related to gibberellin signal transduction pathways and synthetic pathway. The expression of these genes was assessed in two persimmon cultivars, “Dafangshi” and “Nantongxiaofangshi,” by RT-qPCR at different phenological stages and in response to the exogenous application of GA3 (GA treatment) and PAZ (paclobutrazol, a plant growth inhibitor, also called PP333). The results revealed differential expression of 14 of these 22 genes in the two varieties. Subsequently, endogenous hormone levels were assessed of the two varieties, along with the number of internodes and internode length. The results suggested that the persimmon could be used as a valuable and powerful natural candidate for providing information on the functional role of dwarfing.
21
Zombe, Kadango, James Nyirenda, Agape Lumai, and Hellen Phiri. "Impact of Solvent Type on Total Phenol and Flavonoid Content and Sun Protection Factor of Crude Cashew Nutshell Liquid." Sustainable Chemistry 3, no. 3 (July 6, 2022): 334–44. http://dx.doi.org/10.3390/suschem3030021.
Повний текст джерелаАнотація:
Cashew nutshell liquid (CNSL) is a cheap source of natural phenolic compounds that have numerous applications. These phenolic compounds have chemical structures with chromophores similar to those found in synthetic chemical UV-filters, which are present in commercial sunscreen products (SSPs). Thus, this study investigated the impact of solvents on the yield, total phenol content (TPC), total flavonoid content (TFC), and the sun protection factor (SPF) of crude CNSL. The percent yield ranged from (30.4 ± 0.7% to 49.3 ± 3.2%); hexane recorded the lowest yield, while ethanol recorded the highest. Acetone (101.2 ± 2.5 mg GA/g), methanol (99.5 ± 0.10), and chloroform (95.4 ± 3.7 mg GAE/g), recorded the highest TPC respectively, while hexane (33.3 ± 0.7 mg QE/g) recorded the highest TFC. The SPFs ranged from (22.1 ± 1.1 to 16.4 ± 0.8), chloroform (22.1 ± 1.1), acetone (21.5 ± 1.1), and methanol (19.3 ± 1.0) again recorded the highest values respectively, while hexane (16.4 ± 0.8) recorded the lowest. Our results revealed that extracting solvents has a significant impact on the yield and SPF of CNSL. Therefore, we propose that acetone, chloroform, and methanol, either alone or as mixtures, could be the best solvents for extracting CNSL with a good TPC and SPF.
22
Baiocco, Daniele, and Zhibing Zhang. "Microplastic-Free Microcapsules to Encapsulate Health-Promoting Limonene Oil." Molecules 27, no. 21 (October 25, 2022): 7215. http://dx.doi.org/10.3390/molecules27217215.
Повний текст джерелаАнотація:
Fast-moving consumer goods (FMCG) industry has long included many appealing essential oils in products to meet consumers’ needs. Among all, the demand for limonene (LM) has recently surged due to its broad-spectrum health benefits, with applications in cosmetic, detergent, and food products. However, LM is extremely volatile, hence has often been encapsulated for a longer shelf-life. To date, mostly non-biodegradable synthetic polymers have been exploited to fabricate the microcapsule shells, and the resulting microcapsules contribute to the accumulation of microplastic in the environment. So far, information on LM-entrapping microcapsules with a natural microplastic-free shell and their mechanism of formation is limited, and there is lack of an in-depth characterisation of their mechanical and adhesive properties, which are crucial for understanding their potential performance at end-use applications. The present research aims towards developing safe microcapsules with a core of LM fabricated via complex coacervation (CC) using gum Arabic (GA) and fungally sourced chitosan (fCh) as shell precursors. The encapsulation efficiency (EE) for LM was quantified by gas chromatography (GC) separation method. The morphology of microcapsules was investigated via bright-field optical microscopy and scanning electron microscopy, and their mechanical properties were characterised using a micromanipulation technique. Moreover, the adhesive properties of the resulting microcapsules were studied via a bespoke microfluidic device fitted with a polyethylene-terephthalate (PET) substrate and operating at increasingly hydrodynamic shear stress (HSS). Spherical core-shell microcapsules (EE ~45%) with a mean size of 38 ± 2 μm and a relatively smooth surface were obtained. Their mean rupture force and nominal rupture stress were 0.9 ± 0.1 mN and 2.1 ± 0.2 MPa, respectively, which are comparable to those of other microcapsules with synthetic shells, e.g., urea- and melamine-formaldehyde. It was also found that the fCh-GA complexed shell provided promising adhesive properties onto PET films, leading to a microcapsule retention of ~85% and ~60% at low (≤ 50 mPa) and high shear stress (0.9 Pa), respectively. Interestingly, these values are similar to the adhesion data available in literature for microplastic-based microcapsules, such as melamine-formaldehyde (50%–90%). Overall, these findings suggest that microplastics-free microcapsules with a core of oil have been successfully fabricated, and can offer a potential for more sustainable, consumer- and environmentally friendly applications in FMCGs.
23
Spirov, Alexander V., and Ekaterina M. Myasnikova. "Heuristic algorithms in evolutionary computation and modular organization of biological macromolecules: Applications to in vitro evolution." PLOS ONE 17, no. 1 (January 27, 2022): e0260497. http://dx.doi.org/10.1371/journal.pone.0260497.
Повний текст джерелаАнотація:
Evolutionary computing (EC) is an area of computer sciences and applied mathematics covering heuristic optimization algorithms inspired by evolution in Nature. EC extensively study all the variety of methods which were originally based on the principles of selectionism. As a result, many new algorithms and approaches, significantly more efficient than classical selectionist schemes, were found. This is especially true for some families of special problems. There are strong arguments to believe that EC approaches are quite suitable for modeling and numerical analysis of those methods of synthetic biology and biotechnology that are known as in vitro evolution. Therefore, it is natural to expect that the new algorithms and approaches developed in EC can be effectively applied in experiments on the directed evolution of biological macromolecules. According to the John Holland’s Schema theorem, the effective evolutionary search in genetic algorithms (GA) is provided by identifying short schemata of high fitness which in the further search recombine into the larger building blocks (BBs) with higher and higher fitness. The multimodularity of functional biological macromolecules and the preservation of already found modules in the evolutionary search have a clear analogy with the BBs in EC. It seems reasonable to try to transfer and introduce the methods of EC, preserving BBs and essentially accelerating the search, into experiments on in vitro evolution. We extend the key instrument of the Holland’s theory, the Royal Roads fitness function, to problems of the in vitro evolution (Biological Royal Staircase, BioRS, functions). The specific version of BioRS developed in this publication arises from the realities of experimental evolutionary search for (DNA-) RNA-devices (aptazymes). Our numerical tests showed that for problems with the BioRS functions, simple heuristic algorithms, which turned out to be very effective for preserving BBs in GA, can be very effective in in vitro evolution approaches. We are convinced that such algorithms can be implemented in modern methods of in vitro evolution to achieve significant savings in time and resources and a significant increase in the efficiency of evolutionary search.
24
Didi, Dom Alizet, Shiping Su, Faisal Eudes Sam, Richard John Tiika, and Xu Zhang. "Effect of Plant Growth Regulators on Osmotic Regulatory Substances and Antioxidant Enzyme Activity of Nitraria tangutorum." Plants 11, no. 19 (September 28, 2022): 2559. http://dx.doi.org/10.3390/plants11192559.
Повний текст джерелаАнотація:
Plant growth regulators (PGRs) are natural hormones and synthetic hormone analogues. At low concentrations, PGRs have the ability to influence cell division, cell expansion, and cell structure and function, in addition to mediating environmental stress. In this study, experiments were conducted to determine how exogenous PGRs indole acetic acid (IAA), abscisic acid (ABA), and gibberellic acid (GA) influenced osmotic regulatory substances and activity of antioxidant enzymes in Nitraria tangutorum. Using a completely randomized design, IAA, ABA, and GA3 were applied as foliar spray at concentrations of 50 mg/L, 100 mg/L, 150 mg/L, and 200 mg/L to N. tangutorum shrubs. Some selected shrubs did not receive any treatment and served as the control (Ck). The results showed that the foliar spray of IAA, ABA, and GA3 significantly increased the content of osmotic regulatory substances (soluble sugar, soluble protein, and proline) and antioxidant enzymes (SOD and POD) at most concentrations. In addition, the malondialdehyde (MDA) content significantly reduced after treatment, but after regrowth of coppiced shrubs, lipid peroxidation increased and was still lower than Ck. Our study provides evidence that 100 mg/L 150 mg/L, and 200 mg/L concentrations of IAA, ABA, and GA3 treatments are effective for enhancing osmotic regulatory substances and the activity of antioxidant enzymes in N. tangutorum, which offers an effective strategy not only for increasing tolerance to abiotic and biotic stresses, but also improving the adaptability of N. tangutorum shrubs to the environment.
25
Dabade, Sapna Jain, Dheeraj Mandloi, and Amritlal Bajaj. "Molecular Docking and QSAR Studies of Coumarin Derivatives as NMT Inhibitors: Simple Structural Features as Potential Modulators of Antifungal Activity." Letters in Drug Design & Discovery 17, no. 10 (October 12, 2020): 1293–308. http://dx.doi.org/10.2174/1570180817999200617105711.
Повний текст джерелаАнотація:
Background: Treatments of fungal diseases, including Candidiasis, remain not up to scratch in spite of the mounting catalog of synthetic antifungal agents. These have served as the impetus for investigating new antifungal agents based on natural products. Consequently, genetic algorithm-multiple linear regression (GA-MLR) based QSAR (Quantitative Structure-Activity Relationship) studies of coumarin analogues along with molecular docking were carried out. Methods: Coumarin analogues with their MIC values were used to generate the training and test sets of compounds for QSAR models development; the analogues were also docked into the binding pocket of NMT (MyristoylCoA: protein N-myristoyltransferase). Results and Discussion: The statistical parameters for internal and external validation of QSAR analysis (R2 = 0.830, Q2 = 0.758, R2Pred = 0.610 and R2m overall = 0.683 ), Y Randomization, Ridge trace, VIF, tolerance and model criteria of Golbraikh and Tropsha data illustrate the robustness of the best proposed QSAR model. Most of the analogues bind to the electrostatic, hydrophobic clamp and display hydrogen bonding with amino acid residues of NMT. Interestingly, the most active coumarin analogue (MolDock score of -189.257) was docked deeply within the binding pocket of NMT, thereby displaying hydrogen bonding with Tyr107, Leu451, Leu450, Gln226, Cys393 and Leu394 amino acid residues. Conclusion: The combinations of descriptors from various descriptor subsets in QSAR analysis have highlighted the role of atomic properties such as polarizability and atomic van der Waals volume to explain the inhibitory activity. The models and related information may pave the way for important insight into the designing of putative NMT inhibitors for Candida albicans.
26
Moreau, Nicole. "Preface." Pure and Applied Chemistry 85, no. 5 (January 1, 2013): iv. http://dx.doi.org/10.1351/pac20138505iv.
Повний текст джерелаАнотація:
IUPAC’s vision statement declares that the Union advances the worldwide role of chemistry for the benefit of Mankind. And one of its long-range goals states “IUPAC will utilize its global perspective and network to contribute to the enhancement of chemistry education, the career development of young chemical scientists, and the public appreciation of chemistry”. In pursuit of this spirit, the Union established in 2000 the IUPAC Prize for Young Chemists and has been honoring since then outstanding young research chemists at the beginning of their careers by making annual awards. The prizes are given for the most outstanding Ph.D. theses in the area of the chemical sciences, as described in 1000-word essays.As immediate Past President of IUPAC, I was honored to chair the prize selection committee of eminent chemists, who enjoyed reading essays of 41 applicants from 22 countries. After critical evaluation of the originality and excellence of the essays and research results, the committee decided unanimously to award 2012 Prizes for the following six essays:- “Study of the factors affecting the selectivity of catalytic ethylene oligomerization”, Khalid Albahily, University of Ottawa, Ottawa, Canada (following earlier studies at King Saud University, Saudi Arabia and Texas A&M University, College Station, TX, USA)- “Nanowire nanoelectronics: Building interfaces with tissue and cells at the natural scale of biology”, Tzahi Cohen-Karni, Harvard University, Cambridge, MA, USA (following earlier studies at Technion Israel Institute of Technology and Weizmann Institute of Science, Israel)- “Synthetic investigations featuring boron-rich and multidentate chalcoether-containing ligands”, Alexander Spokoyny, Northwestern University, Chicago, IL, USA (following earlier studies at University of California, Los Angeles, CA, USA)- “Quantification of virtual chemical properties: Strain, hyperconjugation, conjugation, and aromaticity”, Judy I-Chia Wu, University of Georgia, Athens, GA, USA (following earlier studies at Tung-Hai University, Taiwan)- “New materials for intermediate-temperature solid oxide fuel cells to be powered by carbon- and sulfur-containing fuels”, Lei Yang, Georgia Institute of Technology, Atlanta, GA, USA (following earlier studies at Beihang University and Tsinghua University, China)- “Transition metal catalysis: Activation of CO2, C–H, and C–O bonds en route to carboxylic acids, biaryls, and N-containing heterocycles”, Charles Yeung, University of Toronto, Toronto, Canada (following earlier studies at University of British Columbia, Vancouver, Canada)All the awardees were invited to present posters on their research at the 44th IUPAC World Chemistry Congress, Istanbul, Turkey, 11–16 August 2012. Upon IUPAC’s invitation, 4 of the 6 winners offered review papers on their research topics for consideration as publications in this issue of Pure and Applied Chemistry.Finally, it is an honor and a pleasure to congratulate each of the winners and their supervisors for winning the 2012 IUPAC Prize for Young Chemists. It is hoped that each of them will continue to contribute to a bright future for chemical sciences and technologies and to take active roles in IUPAC bodies in the future.Nicole MoreauIUPAC Immediate Past President and Chair of the IUPAC Prize Selection Committee
27
Jia, Yuanfeng, Nana Ren, Huadong Yue, Jianru Deng, and Yali Liu. "Preparation and properties of natural gallic acid based rust conversion emulsion." Pigment & Resin Technology 45, no. 3 (May 3, 2016): 191–98. http://dx.doi.org/10.1108/prt-12-2014-0115.
Повний текст джерелаАнотація:
Purpose The paper developed a novel gallic acid-based rust conversion emulsion (RCE) that is applied in the treatment of rusted steels. The purpose of this paper is to investigate the methods for the synthesis of RCE and study the mechanism of rust conversion. Design/methodology/approach Conversion emulsion was prepared using styrene, acrylate and self-developed gallic acid (GA)-based rust converter (GRC) via seed emulsion polymerisation. The polymerisable GRC was synthesised by the ring-opening reaction of glycidyl methacrylate with natural GA. The effects of the GRC dosage and its feeding modes on the RCE synthesis were analysed. The corrosion resistance, surface morphology, composition and mechanism of rust conversion coatings were studied using electrochemical tests, scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. Findings The results showed that conversion coating on rusted steels treated with RCE, with various dosages of GRC (weight per cent), synthesised using seed emulsion polymerisation, exhibited the best adhesion and corrosion resistance. Raman spectroscopy revealed that RCE converted the original multiphase rust into stable crystalline phases of α-Fe2O3 and Fe3O4. According to XPS and energy dispersive X-ray analysis, the phenolic hydroxyl groups of RCE were proposed to chelate with Fe ions to form macromolecular ferrum compounds. Research limitations/implications The pre-rusted steels demonstrated a better corrosion resistance than rust-free steels after treatment with RCE. Practical implications The paper developed a novel GA-based RCE with high efficiency and environment-friendly method. Originality/value This work is expected to replace the conventional rust conversion paints and cause a significant impact on extending the service life of rusted steels.
28
Chen, Zhi, Shi-Chao Chen, Bo Li, Yong-An Yang, and Jing Zhang. "Synthesis and Evaluation of Glycyrrhetic Acid-aromatic Hybrids as Anti-inflammatory Agents." Medicinal Chemistry 16, no. 6 (September 7, 2020): 715–23. http://dx.doi.org/10.2174/1573406415666190603095502.
Повний текст джерелаАнотація:
Background: : Inflammation is a biological response of body tissues to harmful stimuli, so it is desirable to search for novel anti-inflammatory agents with improved pharmaceutical profiles and reduced adverse effects. Objective: : This study was to explore natural anti-inflammatory agents and improve therapeutic application of glycyrrhetic acid (GA) through molecular hybridization with active aromatics. Methods: : Fourteen novel GA-aromatic hybrids were synthesized and evaluated for their antiinflammatory activities by inhibiting LPS-induced nitric oxide (NO) release in RAW264.7 cells. The synthesized compounds were characterized by single-crystal X-ray diffraction, 1H NMR, 13C NMR and HRMS. Result: : The structure-activity relationship (SAR) study indicated that compounds with styryl displayed better NO inhibitory activity. Among them, compounds 2a and 3c exhibited the most promising activity with IC50 values of 9.93 μM and 12.25 μM, respectively. In addition, X-ray singlecrystal diffraction data for compounds 2e and 3c showed that the absolute configuration of GA skeleton was consistent with that of natural 18 β-glycyrrhetic acid. Conclusion: : The results showed that GA-aromatic hybrids were a new class of anti-inflammatory agents and this study provided useful information on further optimization.
29
Yoshida, Eiichi, Satoshi Murata, Akiya Kamimura, Kohji Tomita, Haruhisa Kurokawa, and Shigeru Kokaji. "Evolutionary Motion Synthesis for a Modular Robot Using Genetic Algorithm." Journal of Robotics and Mechatronics 15, no. 2 (April 20, 2003): 227–37. http://dx.doi.org/10.20965/jrm.2003.p0227.
Повний текст джерелаАнотація:
An evolutionary motion synthesis method using genetic algorithm (GA) is presented for self-reconfigurable modular robot M-TRAN designed to realize various robotic motions and three-dimensional structures. The proposed method is characterized by its capacity to derive feasible solutions for complex synthesis problem of M-TRAN through natural genetic representation. For this purpose, the behavior of the robot is described using a motion sequence including both the dynamic motions and configuration changes of the robot. It is a series of segments each of which can specify simultaneous motor actuations and selfreconfiguration by connection/disconnection, starting from a given initial configuration. This simple description can be straightforwardly encoded into genetic representation to which genetic operations can be applied in a natural manner. We adopt traveling distance achieved by the evolved motion as the fitness function of GA. To verify the effectiveness of the proposed method, we have conducted simulations of evolutionary motion synthesis for certain initial configurations. Consequently, we confirm various adaptive motions are acquired according to different initial configurations and fitness functions. We also verify the physical feasibility of the evolved motions through experiments using hardware module M-TRAN II.
30
Schwachtje, Jens, and Ian T. Baldwin. "Smoke exposure alters endogenous gibberellin and abscisic acid pools and gibberellin sensitivity while eliciting germination in the post-fire annual, Nicotiana attenuata." Seed Science Research 14, no. 1 (March 2004): 51–60. http://dx.doi.org/10.1079/ssr2003154.
Повний текст джерелаАнотація:
Exposure to smoke is required for the germination of seeds from dormant genotypes ofNicotiana attenuata, a post-fire annual of the Great Basin Desert. Germination can be elicited by GA1,3,4,7treatments and inhibited by the GA biosynthesis inhibitor, paclobutrazol (PAC), abscisic acid (ABA) and terpenes leached from unburned litter of the plant’s natural habitat. We analysed the endogenous GA and ABA dynamics during the 22 h after imbibition, when smoke-treated dormant seeds commit to germination. Extractable GA1+3pools decreased in all seeds, but the decrease was more dramatic within 2 h of smoke exposure, which was followed by an increase between hours 2 and 4. Extractable ABA pools increased shortly after imbibition and remained stable in control, water-treated seeds, but decreased sharply in smoke-treated seeds. PAC completely inhibited smoke-induced germination when seeds were treated for 12 h after smoke exposure, consistent with the requirement ofde novoGA synthesis for germination. Smoke treatment in the dark did not result in germination, whereas GA3treatment did, a result consistent with phytochrome-mediated GA biosynthesis. Smoke exposure dramatically increased the sensitivity of seeds to exogenous GA3treatments in both the light and dark, and light exposure increased this sensitivity an additional tenfold. Taken together, these results suggest that while germination requires endogenous GA synthesis, the effects of smoke treatment increase GA sensitivity, which is correlated with a decrease in endogenous ABA pools.
31
Feng, Zhe, Xin Liu, Yu Wang, and Changgong Meng. "Recent Advances on Gallium-Modified ZSM-5 for Conversion of Light Hydrocarbons." Molecules 26, no. 8 (April 13, 2021): 2234. http://dx.doi.org/10.3390/molecules26082234.
Повний текст джерелаАнотація:
Light olefins are key components of modern chemical industry and are feedstocks for the production of many commodity chemicals widely used in our daily life. It would be of great economic significance to convert light alkanes, produced during the refining of crude oil or extracted during the processing of natural gas selectively to value-added products, such as light alkenes, aromatic hydrocarbons, etc., through catalytic dehydrogenation. Among various catalysts developed, Ga-modified ZSM-5-based catalysts exhibit superior catalytic performance and stability in dehydrogenation of light alkanes. In this mini review, we summarize the progress on synthesis and application of Ga-modified ZSM-5 as catalysts in dehydrogenation of light alkanes to olefins, and the dehydroaromatization to aromatics in the past two decades, as well as the discussions on in-situ formation and evolution of reactive Ga species as catalytic centers and the reaction mechanisms.
32
Deng, Sui-Ping, Yi-Li Yang, Xing-Xing Cheng, Wen-Rong Li, and Ji-Ye Cai. "Synthesis, Spectroscopic Study and Radical Scavenging Activity of Kaempferol Derivatives: Enhanced Water Solubility and Antioxidant Activity." International Journal of Molecular Sciences 20, no. 4 (February 23, 2019): 975. http://dx.doi.org/10.3390/ijms20040975.
Повний текст джерелаАнотація:
Kaempferol (Kae) is a natural flavonoid with potent antioxidant activity, but its therapeutic use is limited by its low aqueous solubility. Here, a series of Kae derivatives were synthesized to improve Kae dissolution property in water and antioxidant activity. These compounds included sulfonated Kae (Kae-SO3), gallium (Ga) complexes with Kae (Kae-Ga) and Kae-SO3 (Kae-SO3-Ga). The compound structures were characterized by high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and thermal methods (TG/DSC). The results showed that a sulfonic group (-SO3) was successfully tethered on the C3’ of Kae to form Kae-SO3. And in the metal complexation, 4-CO and 3-OH of the ligand participated in the coordination with Ga(III). The metal-to-ligand ratio 1:2 was suggested for both complexes. Interestingly, Kae-SO3-Ga was obviously superior to other compounds in terms of overcoming the poor water-solubility of free Kae, and the solubility of Kae-SO3-Ga was about 300-fold higher than that of Kae-Ga. Furthermore, the evaluation of antioxidant activities in vitro was carried out for Kae derivatives by using α,α-diphenyl-β-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging. The results showed that Kae-SO3-Ga was also optimal for scavenging free radicals in a dose-dependent manner. These data demonstrate that sulfonate kaempferol-gallium complex has a promising future as a potential antioxidant and as a potential therapeutic agent for further biomedical studies.
33
Hosseinikhah, Sahar Saadat, Bi Bi Fatemeh Mirjalili, Naeimeh Salehi, and Abdolahamid Bamoniri. "Gum arabic-OPO3H2 as a new natural-based green catalyst for the one-pot pseudo-four-component synthesis of naphtho[1,2-e][1,3]oxazines." RSC Advances 10, no. 66 (2020): 40508–13. http://dx.doi.org/10.1039/d0ra07199d.
Повний текст джерела
34
Bachra, Yahya, Ayoub Grouli, Fouad Damiri, Mohammed Talbi, and Mohammed Berrada. "A Novel Superabsorbent Polymer from Crosslinked Carboxymethyl Tragacanth Gum with Glutaraldehyde: Synthesis, Characterization, and Swelling Properties." International Journal of Biomaterials 2021 (November 20, 2021): 1–14. http://dx.doi.org/10.1155/2021/5008833.
Повний текст джерелаАнотація:
Nowadays, current global environmental problems include measures to eliminate or reduce the negative impact of chemicals from petroleum sources and, therefore, the use of materials from natural resources is increasingly recommended. In this context, natural-based superabsorbent polymers derived from polypeptides and polysaccharides have undergone chemical and biochemical modifications to improve their ability to absorb and retain large amounts of liquids. In the present paper, a new process has been used to overcome the side effects of radical polymerization in the manufacture of conventional polyacrylate superabsorbents (SAPs). Tragacanth gum (TG) was selected to prepare a new superabsorbent material (CMTG-GA) based on carboxymethyl tragacanth (CMTG) crosslinked with glutaraldehyde (GA). The characterization of the polymer was carried out by FTIR, TGA, XRD, and SEM. The effect of the amount of crosslinking agent and the pH on the water absorption capacity was also examined. Subsequently, swelling studies were performed using free swelling capacity (FSC) and centrifuge retention capacity (CRC) techniques in distilled water, tap water, and saline solution. The results showed that the CRC of the new material is not less than 42.1 g/g, which was observed for a ratio of 20% by weight of GA to CMTG. Likewise, the maximum absorption results were 43.9 and 32.14 g/g, respectively, for FSC and CRC at pH 8.0. In addition, a comparison of the swelling capacities of the synthesized product with a commercial SAP extracted from a baby diaper, well known in the Moroccan market, showed that the performances were very similar.
35
Vural, Hasibe. "The effect mechanism of Ginnalin A as a homeopathic agent on various cancer cell lines." Open Chemistry 16, no. 1 (August 15, 2018): 790–95. http://dx.doi.org/10.1515/chem-2018-0084.
Повний текст джерелаАнотація:
AbstractEpidemiological and experimental studies have shown that natural products are beneficial for the protection against cancer. Maple syrup is a natural sweetener often consumed throughout the world. Maple syrup contains various phenolic compounds such as lignans, coumarin and Ginnalin A (GA). The aim of this study was to investigate the effects of GA shown to have cytotoxic and apoptotic effects in several human carcinoma cell lines. The effect of GA on cell viability was determined by a XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) assay as described in the manufacturer’s instruction. Total RNA was isolated from cancer cells using TRIzol Reagent and reverse transcription was performed using Script™ cDNA Synthesis Kit (Bio-Rad) according to the manufacturer’s instructions. Expressions of important genes in apoptosis including MMP-2, MMP-9, TIMP-1, TIMP-2, CDH1 and CDH2, were investigated in dose and control groups by qPCR (quantitative real time- polymerase chain reaction).When compared with the control group, qPCR results illustrated that a significant increase in gene expression was observed in the expressions of CDH1, TIMP-1 and TIMP-2 by 3.52, 5.13 and 2.67 times respectively. Research has shown that Ginnalin A can demonstrate an anti-metastatic effect by regulating the expression of important genes in metastasis on cancer cell lines. Furthermore, in this study the activation of caspase-8 in apoptotic signaling pathways and the pro-apoptotic caspases required for extrinsic apoptotic signal transduction was defined.
36
Shi, Shengyu, Lifeng Yao, Linlin Li, Zehui Wu, Zhihao Zha, Hank F. Kung, Lin Zhu, and De-Cai Fang. "Synthesis of novel technetium-99m tricarbonyl-HBED-CC complexes and structural prediction in solution by density functional theory calculation." Royal Society Open Science 6, no. 11 (November 2019): 191247. http://dx.doi.org/10.1098/rsos.191247.
Повний текст джерелаАнотація:
HBED-CC ( N,N' -bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylene diamine- N,N' -diacetic acid, L 1 ) is a common bifunctional chelating agent in preparation of 68 Ga-radiopharmaceuticals. Due to its high stability constant for the Ga 3+ complex (logK GaL = 38.5) and its acyclic structure, it is well known for a rapid and efficient radiolabelling at ambient temperature with Gallium-68 and its high in vivo stability. [ 99m Tc][Tc(CO) 3 (H 2 O) 3 ] + is an excellent precursor for radiolabelling of biomolecules. The aim of this study was to develop a novel preparation method of 99m Tc-HBED-CC complexes. In this study, HBED-CC-NI (2,2'-(ethane-1,2-diylbis((2-hydroxy-5-(3-((2-(2-nitro-1H-imidazol-1-yl)ethyl)amino)-3-oxopropyl)benzyl)-azanediyl))-diacetic acid, L 2 ), a derivative of HBED-CC, was designed and synthesized. Both L 1 and L 2 were radiolabelled by [ 99m Tc][Tc(CO) 3 (H 2 O) 3 ] + successfully for the first time. In order to explore the coordination mode of metal and chelates, non-radioactive Re(CO) 3 L 1 and Re(CO) 3 L 2 were synthesized and characterized spectroscopically. Tc(CO) 3 L 1 and Tc(CO) 3 L 2 in solution were calculated by density functional theory and were analysed with radio-HPLC chromatograms. It showed that [ 99m Tc]Tc(CO) 3 L 2 forms two stable diastereomers in solution, which is similar to those of [ 68 Ga]Ga-HBED-CC complexes. Natural bond orbital analysis through the natural population charges revealed a charge transfer between [ 99m Tc][Tc(CO) 3 ] + and L 1 or L 2 . The experimental results showed that tricarbonyl technetium might form stable complex with HBED-CC derivatives, which is useful for the future application of using HBED-CC as a bifunctional chelating agent in developing new 99m Tc-radiopharmaceuticals as diagnostic imaging agents.
37
Gong, Pi-Xian, Hui-Jing Li, Meirong Wang, Yun-Fei Cheng, and Yan-Chao Wu. "Synthesis of natural product inulavosin via Ga(OTf)3-Catalyzed Hetero Diels–Alder Dimerization of salicyl alcohol derivative." Natural Product Research 33, no. 20 (October 8, 2018): 2911–16. http://dx.doi.org/10.1080/14786419.2018.1509338.
Повний текст джерела
38
Hu, Lingfeng, Pengkai Wang, Zhaodong Hao, Ye Lu, Guoxia Xue, Zijian Cao, Haoxian Qu, Tielong Cheng, Jisen Shi, and Jinhui Chen. "Gibberellin Oxidase Gene Family in L. chinense: Genome-Wide Identification and Gene Expression Analysis." International Journal of Molecular Sciences 22, no. 13 (July 2, 2021): 7167. http://dx.doi.org/10.3390/ijms22137167.
Повний текст джерелаАнотація:
GAox is a key enzyme for the transformation of gibberellins, and belongs to the 2-ketoglutarate dependent dioxygenase gene family (2ODD). However, a systematic analysis of GAox in the angiosperm L. chinense has not yet been reported. Here, we identified all LcGAox gene family members in L. chinense, which were classified into the three subgroups of GA20ox, C19GA2ox, and C20GA2ox. Comparison of the gene structure, conserve motifs, phylogenetic relationships, and syntenic relationships of gibberellin oxidase gene families in different species indicated that the gene functional differences may be due to the partial deletion of their domains during evolution. Furthermore, evidence for purifying selection was detected between orthologous GAox genes in rice, grape, Arabidopsis, and L. chinense. Analysis of the codon usage patterns showed that mutation pressure and natural selection might have induced codon usage bias in angiosperms; however, the LcGAox genes in mosses, lycophytes, and ambarella plants exhibited no obvious codon usage preference. These results suggested that the gibberellin oxidase genes were more primitive. The gene expression pattern was analyzed in different organs subjected to multiple abiotic stresses, including GA, abscisic acid (ABA), and chlormequat (CCC) treatment, by RNA-seq and qRT-PCR, and the stress- and phytohormone-responsive cis-elements were counted. The results showed that the synthesis and decomposition of GA were regulated by different LcGAox genes in the vegetative and reproductive organs of L. chinense, and only LcGA2ox1,4, and 7 responded to the NaCl, polyethylene glycol, 4 °C, GA, ABA, and CCC treatment in the roots, stems, and leaves of seedlings at different time periods, revealing the potential role of LcGAox in stress resistance.
39
Casagrande, Naike, Cinzia Borghese, Laura Gabbatore, Laura Morbiato, Marta De Zotti, and Donatella Aldinucci. "Analogs of a Natural Peptaibol Exert Anticancer Activity in Both Cisplatin- and Doxorubicin-Resistant Cells and in Multicellular Tumor Spheroids." International Journal of Molecular Sciences 22, no. 16 (August 4, 2021): 8362. http://dx.doi.org/10.3390/ijms22168362.
Повний текст джерелаАнотація:
Peptaibols, by disturbing the permeability of phospholipid membranes, can overcome anticancer drug resistance, but their natural hydrophobicity hampers their administration. By a green peptide synthesis protocol, we produced two water-soluble analogs of the peptaibol trichogin GA IV, termed K6-Lol and K6-NH2. To reduce production costs, we successfully explored the possibility of changing the naturally occurring 1,2-aminoalcohol leucinol to a C-terminal amide. Peptaibol activity was evaluated in ovarian cancer (OvCa) and Hodgkin lymphoma (HL) cell lines. Peptaibols exerted comparable cytotoxic effects in cancer cell lines that were sensitive—and had acquired resistance—to cisplatin and doxorubicin, as well as in the extrinsic-drug-resistant OvCa 3-dimensional spheroids. Peptaibols, rapidly taken up by tumor cells, deeply penetrated and killed OvCa-spheroids. They led to cell membrane permeabilization and phosphatidylserine exposure and were taken up faster by cancer cells than normal cells. They were resistant to proteolysis and maintained a stable helical structure in the presence of cancer cells. In conclusion, these promising results strongly point out the need for further preclinical evaluation of our peptaibols as new anticancer agents.
40
Ortiz-Sanchez, Elizabeth, Tracy R. Daniels, Gustavo Helguera, Otoniel Martinez-Maza, Benjamin Bonavida, and Manuel L. Penichet. "The Role of Iron in the Cytotoxicity Induced in Hematopoietic Malignant Cell Lines by an Anti-Transferrin Receptor IgG3-Avidin Fusion Protein and Gambogic Acid." Blood 110, no. 11 (November 16, 2007): 4204. http://dx.doi.org/10.1182/blood.v110.11.4204.4204.
Повний текст джерелаАнотація:
Abstract The human transferrin receptor (hTfR) is a cell surface glycoprotein responsible for iron uptake, which is required for several cellular reactions including respiration and DNA synthesis. In cancer cells, the hTfR is over-expressed due to the high amount of iron required to maintain the uncontrolled cell proliferation. This makes the cancer cells highly sensitive to death induced by iron starvation. In addition to iron uptake, the TfR may also play a role in cell growth signaling. We have developed a mouse/human chimeric anti-human transferrin receptor IgG3-avidin fusion protein (anti-hTfR IgG3-Av) that induces cell death in human malignant B-cells such as IM9 and ARH-77 (B lymphoblastoid cell lines). The TfR is constitutively internalized and recycled back to cell surface. Anti-hTfR IgG3-Av binding to the hTfR disrupts this cycling and redirects the hTfR to lysosomal compartments where hTfR is presumably degraded. This promotes a state of iron starvation that induces cancer cell death by apoptosis, which can be blocked by iron supplementation. However, the cytotoxic effect induced by anti-hTfR IgG3-Av was minor or absent in U266 (multiple myeloma cell line). Gambogic acid (GA), a natural compound from traditional Chinese medicine, was previously shown to bind the TfR, blocking its internalization and inducing apoptosis in an iron independent manner in Jurkat (acute T cell leukemia) and HL-60 (acute promyelocytic leukemia) cell lines. The goal of the present work is to explore the cytotoxic effect of anti-hTfR IgG3-Av and GA alone or in combination in a panel of hematopoietic malignant cell lines and understand the relevance of iron in the cytotoxicity. We demonstrate that GA inhibits the proliferation of Ramos, HS-sultan, Raji (Burkitt’s lymphomas), IM9, U266, Jurkat and HL-60 cell lines. Our results showed that 0.3 μM GA at 24 h decreases cell proliferation by 70–90%, and 95–99.9% at 48 h, in all cell lines tested. We also observed morphological changes in the cells treated with GA consistent with cell death. Importantly, using ferric ammonium citrate as an iron supplement, we confirmed that the cytotoxic effect of GA in the cell lines tested is iron independent. This work also demonstrates, for the first time, that anti-hTfR IgG3-Av has a potent cytotoxic effect in the panel of leukemia and lymphoma cell lines tested above. Additionally, we confirmed that anti-hTfR IgG3-Av induces cell death in an iron dependent manner. Since both anti-hTfR IgG3-Av and GA target the TfR, we tested the effect of the combination of these components. Despite a potential antagonistic effect due to the fact that anti-hTfR IgG3-Av decreases the cell surface levels of the hTfR and GA blocks its internalization, the combination of anti-hTfR IgG3-Av plus GA enhanced the cytotoxicity, including cases of synergy, of either one alone in the cell lines tested. Studies are currently underway to understand the role of iron in the enhancement of toxicity. Our results suggest that anti-hTfR IgG3-Av and GA, alone or in combination, could be an effective treatment option for various hematopoietic malignancies.
41
Fidanovski, Dusko, Vladislav Milev, Aleksandar Sajkovski, Antoni Hristovski, Aspasija Sofijanova, Ljiljana Kojic, and Mica Kimovska. "Mortality risk factors in premature infants with respiratory distress syndrome treated by mechanical ventilation." Srpski arhiv za celokupno lekarstvo 133, no. 1-2 (2005): 29–35. http://dx.doi.org/10.2298/sarh0502029f.
Повний текст джерелаАнотація:
Respiratory distress syndrome (RDS) is the most common cause of respiratory failure and requirement for mechanical ventilation (MV) of newborns. RDS is also common cause of mortality and severe morbidity in premature infants. In developing countries, despite facilities for respiratory care of newborn infants, RDS mortality rate and percentage of complications still remain high in comparison to the developed countries. Survival rates of RDS infants requiring MV ranged from 25% in those newborns with birth weight <1000 grams up to 53% in those with birth weight >2500 grams. There have been limited data about causes of high mortality rate in infants with RDS from developing countries. AIM The objectives of the study were to determine (I) the incidence of severe RDS at Pediatric Intensive Care Unit (PICU), University Children's Hospital Skopje (UCHS) and main characteristics of infants with RDS, as well as (II) the survival rate and mortality risk factors of these infants. MATERIAL AND METHODS The study included 126 premature infants with clinical and radiological signs of RDS requiring mechanical ventilation who were admitted to PICU, UCHS between January 1996 and December 2003. The mean gestational age (GA) of the infants was 31.5+2.5 weeks, and the mean birth weight (BW) was 1663+489 grams. The management of newborns with RDS at PICU, UCHS, follows the standard protocol, with emphasis on minimal manipulation, maintenance of thermo neutral environment, administration of humidified oxygen and non-invasive cardio respiratory monitoring. Pressure-limited time-cycled mechanical ventilation with pediatric/neonatal ventilators was performed in all infants. In those newborn infants with clinical and radiological signs of RDS and need for MV with FiO2>0.4, synthetic (Exosurf) or natural (Survanta) surfactants were administered. Out of all newborns, 43 infants (34%) were not treated with surfactant, because it was not available at that time. RESULTS In the period 1996-2003, out of 1722 consecutive admissions to PICU, 693 hospitalized infants had neonatal RDS (40.2%). A total of 210 (30.3%) infants with RDS required intubation and PPV, and 126 met the inclusion criteria for this study. Surfactant replacement therapy (up to two doses) was given to 83 (65.8%) infants. Most of neonates (80 or 634%) were born at two maternity hospitals in Skopje, and others were transferred from regional maternity hospitals in Macedonia. The relation between perinatal characteristics, disease severity and outcome was illustrated in Table 2. There was higher risk of mortality in infants with lower birth weight, lower Apgar score (minutes 1 and 5), and shorter gestational age. Expected admission values of VI as well as other parameters of illness severity were not significantly associated with higher risk of mortality. The newborns with air-leak sy (any form) and pulmonary hemorrhage had significantly higher risk of dying, while the risk of mortality was significantly lower in infants with sepsis and BPD as complications in studied cohort. The findings of logistic regression analysis for mortality risk factors were presented in Table 3. The minimal model identified a number of factors as independently associated with significantly higher risk of mortality. Infant birth weight ?1500 grams, admission VI ?0.2 mmHg and air leak sy (any form) as complication significantly increased the risk of dying in infants with RDS. BPD was significantly associated with survival in studied cohort. CONCLUSION In spite of the implementation of high technology in Neonatal Intensive Care in our country, the mortality rate of the infants with RDS is high, but is not different from that in developing countries. The improvement of perinatal care and diminution of risk factors, common use of surfactant as well as antenatal steroids could most probably result in better outcome of neonatal RDS.
42
Ponce, Concepcion P., and J. Theo Kloprogge. "Urea-Assisted Synthesis and Characterization of Saponite with Different Octahedral (Mg, Zn, Ni, Co) and Tetrahedral Metals (Al, Ga, B), a Review." Life 10, no. 9 (August 28, 2020): 168. http://dx.doi.org/10.3390/life10090168.
Повний текст джерелаАнотація:
Clay minerals surfaces potentially play a role in prebiotic synthesis through adsorption of organic monomers that give rise to highly concentrated systems; facilitate condensation and polymerization reactions, protection of early biomolecules from hydrolysis and photolysis, and surface-templating for specific adsorption and synthesis of organic molecules. This review presents processes of clay formation using saponite as a model clay mineral, since it has been shown to catalyze organic reactions, is easy to synthesize in large and pure form, and has tunable properties. In particular, a method involving urea is presented as a reasonable analog of natural processes. The method involves a two-step process: (1) formation of the precursor aluminosilicate gel and (2) hydrolysis of a divalent metal (Mg, Ni, Co, and Zn) by the slow release of ammonia from urea decomposition. The aluminosilicate gels in the first step forms a 4-fold-coordinated Al3+ similar to what is found in nature such as in volcanic glass. The use of urea, a compound figuring in many prebiotic model reactions, circumvents the formation of undesirable brucite, Mg(OH)2, in the final product, by slowly releasing ammonia thereby controlling the hydrolysis of magnesium. In addition, the substitution of B and Ga for Si and Al in saponite is also described. The saponite products from this urea-assisted synthesis were tested as catalysts for several organic reactions, including Friedel–Crafts alkylation, cracking, and isomerization reactions.
43
de Brito, B. M. A., Juliana Melo Cartaxo, Julliana Marques Rocha Costa, Heber Carlos Ferreira, and Gelmires Araújo Neves. "Comparative Study of Organoclays with Ionic Surfactant." Materials Science Forum 798-799 (June 2014): 9–14. http://dx.doi.org/10.4028/www.scientific.net/msf.798-799.9.
Повний текст джерелаАнотація:
The clays of the smectite group, mainly montmorillonite, are widely used in the production of organoclays due to the small dimensions of the crystals, high cation exchange capacity (CEC), and swelling capacity in water, which lead to a rapid and efficient intercalation of organic compounds used in the synthesis. In this context, this research was intended to make a comparative study of clays organofilized with ionic surfactants through their respective CEC. We selected four samples of bentonites, namely Chocolate (Boa Vista, PB), Brasgel (industrial), Dark Bentonite (Pedra Lavrada, PB) and M400 Bentonite (industrial). The natural samples were characterized through XRD, EDX, TA and GA, and the organofilized ones through XRD. The characterization tests showed that the samples are composed of clay minerals of the smectite group, the CEC values were insignificant changes when comparing the values of natural and activated clays with sodium carbonate. And the levels indicated by the CEC for the ionic surfactant Praepagem HY proved insufficient to transform the organophilic clays, as the nominees for the ionic surfactant Praepagem WB led to adequate results regarding the incorporation of the surfactant in the clay fraction of the studied samples.
44
Alidha Rahmani, Indri, Ani Mulyasuryani, and Ulfa Andayani. "Synthesis of Chitosan Magnetic Nanoparticles using Glutaraldehyde and Tripolyphosphate as Crosslinker." Journal of Pure and Applied Chemistry Research 11, no. 2 (August 31, 2022): 143–48. http://dx.doi.org/10.21776/ub.jpacr.2022.011.02.683.
Повний текст джерелаАнотація:
Chitosan is an abundant natural polymer, which able to adsorb Pb2+. However, chitosan has the drawback of being unstable in acid and alkaline conditions, so it needs cross-linking. In this article, we will compare the usage of two crosslinkers, glutaraldehyde (GD) and tripolyphosphate (TPP), to solve these issues. The synthesis of chitosan magnetic nanoparticles was carried out by co-precipitation with the addition of glutaraldehyde under acidic conditions and the addition of TPP under alkaline conditions. The results showed that the FTIR spectrum gave characteristic bands at 3131.96 cm-1 (OH and NH), 1635.86 cm-1 (C=O), 1401.97 cm-1 (CN), ~1110 cm-1 (COC), and ~617 cm-1 (Fe-O). SEM analysis showed that the surface morphology of CMNP-GA particle aggregation was clear more than that of CMNP-TPP. The size of the synthesized nanoparticles was determined by PSA analysis, which was 131.95 µm and 137.10 µm, respectively. The results of the XRD analysis showed that, in addition to the Fe3O4 and chitosan phases, the produced CMNP also contained γFe2O3 phase, which was considered to be caused by Fe3O4 oxidation
45
Bassanini, Ivan, Silvia Parapini, Erica E. Ferrandi, Elena Gabriele, Nicoletta Basilico, Donatella Taramelli, and Anna Sparatore. "Design, Synthesis and In Vitro Investigation of Novel Basic Celastrol Carboxamides as Bio-Inspired Leishmanicidal Agents Endowed with Inhibitory Activity against Leishmania Hsp90." Biomolecules 11, no. 1 (January 5, 2021): 56. http://dx.doi.org/10.3390/biom11010056.
Повний текст джерелаАнотація:
The natural triterpene celastrol (CE) is here used as lead compound for the design and synthesis of a panel of eleven CE carboxamides that were tested in vitro for their growth inhibitory activity against Leishmania infantum and L.tropica parasites. Among them, in vitro screening identified four basic CE carboxamides endowed with nanomolar leishmanicidal activity, against both the promastigotes and the intramacrophage Leishmania amastigotes forms. These compounds also showed low toxicity toward two human (HMEC-1 and THP-1) and one murine (BMDM) cell lines. Interestingly, the most selective CE analogue (compound 3) was also endowed with the ability to inhibit the ATPase activity of the Leishmania protein chaperone Hsp90 as demonstrated by the in vitro assay conducted on a purified, full-length recombinant protein. Preliminary investigations by comparing it with the naturally occurring Hsp90 active site inhibitor Geldanamycin (GA) in two different in vitro experiments were performed. These promising results set the basis for a future biochemical investigation of the mode of interaction of celastrol and CE-inspired compounds with Leishmania Hsp90.
46
Inokuchi, Yoshio, Fabio Quaglia, Akikazu Hirashima, Yoshihiro Yamamoto, Hideko Kaji, and Akira Kaji. "Role of ribosome recycling factor in natural termination and translational coupling as a ribosome releasing factor." PLOS ONE 18, no. 2 (February 24, 2023): e0282091. http://dx.doi.org/10.1371/journal.pone.0282091.
Повний текст джерелаАнотація:
The role of ribosome recycling factor (RRF) of E. coli was studied in vivo and in vitro. We used the translational coupling without the Shine-Dalgarno sequence of downstream ORF (d-ORF) as a model system of the RRF action in natural termination of protein synthesis. For the in vivo studies we used the translational coupling by the adjacent coat and lysis genes of RNA phage GA sharing the termination and initiation (UAAUG) and temperature sensitive RRF. The d-ORF translation was measured by the expression of the reporter lacZ gene connected to the 5’-terminal part of the lysis gene. The results showed that more ribosomes which finished upstream ORF (u-ORF) reading were used for downstream reading when RRF was inactivated. The in vitro translational coupling studies with 027mRNA having the junction sequence UAAUG with wild-type RRF were carried out with measuring amino acids incorporation. The results showed that ribosomes released by RRF read downstream from AUG of UAAUG. In the absence of RRF, ribosomes read downstream in frame with UAA. These in vivo and in vitro studies indicate that RRF releases ribosomes from mRNA at the termination codon of u-ORF. Furthermore, the non-dissociable ribosomes read downstream from AUG of UAAUG with RRF in vitro. This suggests that complete ribosomal splitting is not required for ribosome release by RRF in translational coupling. The data are consistent with the interpretation that RRF functions mostly as a ribosome releasing factor rather than ribosome splitting factor. Additionally, the in vivo studies showed that short (less than 5 codons) u-ORF inhibited d-ORF reading by ribosomes finishing u-ORF reading, suggesting that the termination process in short ORF is not similar to that in normal ORF. This means that all the preexisting studies on RRF with short mRNA may not represent what goes on in natural termination step.
47
Mann, Markus, Michael Küpers, Grit Häuschen, Martin Finsterbusch, Dina Fattakhova-Rohlfing, and Olivier Guillon. "The influence of hafnium impurities on the electrochemical performance of tantalum substituted Li7La3Zr2O12 solid electrolytes." Ionics 28, no. 1 (October 7, 2021): 53–62. http://dx.doi.org/10.1007/s11581-021-04300-w.
Повний текст джерелаАнотація:
AbstractGarnet-based Li7La3Zr2O12 (LLZO) is considered one of the most promising oxide-ceramic solid electrolyte materials for inorganic all-solid-state batteries. Dopants and substituents like Al, Ta, Nb, Ga, and W were shown to have a high impact on the total ionic conductivity, increasing it from 10−6 S/cm up to 10−3 S/cm. However, natural zirconium sources always contain a small amount of hafnium which could also act as dopant, but the separation of these two elements is complicated and expensive. In this work, we investigate the influence of various Hf-impurity concentrations on the performance of tantalum-doped LLZO. We synthesised Li6.45Al0.05La3Zr1.6−xHfxTa0.4O12 (LLZHO with x = 0 – 1.6) via conventional solid-state synthesis and have demonstrated that up to x = 0.1, hafnium impurities do not have a significant impact on the performance of the material. Above this concentration, the Li-ion conductivity is steadily reduced to around 70% when zirconium is fully substituted by hafnium resulting in Li6.45Al0.05La3Hf1.6Ta0.4O12. As the purity of Zr precursors has a great impact on their price, these findings can help to reduce the price of LLZO in general, as lower grade zirconium can be used in industrial scale applications.
48
Elahi, Nahid Jalalian, Masoud Salehmoghadam, Danial Taherzadeh, Alireza Hashemzadeh, and Majid Darroudi. "Ammonia Sensing and Cytotoxicity of the Biosynthesized Silver Nanoparticle by Arabic Gum (AG)." Recent Patents on Biotechnology 13, no. 3 (August 6, 2019): 228–38. http://dx.doi.org/10.2174/1872208313666190118123141.
Повний текст джерелаАнотація:
Background: The green synthesizing procedure of Silver nanoparticles (AgNPs) has been performed through the usage of a natural polysaccharide; Arabic gum (AG) as a stabilizing/ capping agent. For characterization of AgNPs, TEM, particle size analyzer and UV-Vis were used. Methods: The aim of our project was to identify biosynthesized AgNPs for sensing ammonia and to explore its toxicity on Neuro-2A cells. We also reviewed the patents for biosynthesized AgNO3 and ammonia sensing. The optimal conditions for the synthesis of AgNPs in AG consist of utilizing (0.1g) AG in dH2O (70 ml), 10 ml of 1 mM silver solution and 0.1 mM (AA) at 70°C stirring for 30 minutes. The AgNPs cytotoxicity was evaluated on Neuro-2A cells; consequently, ammonia was sensed with the lowest possible concentration of 10-6. Results: Particle size analyzer displayed the mean diameter of about 70 nm for the sphericalshaped Ag-NPs. UV–Vis revealed that the prepared AgNPs were ammonia sensitive in solution as the concentration of ammonia was increased. The cytotoxicity of AgNPs indicated lower Cell viability at higher concentrations of the AG-capped AgNPs. Conclusion: By synthesis of AgNPs in GA by using AA, we successfully prepared a sensor to diagnose ammonia in a cell and sensing its level at concentrations of 10-6 M. In this study, no therapeutic application has been shown, but this method could be utilized industrially for therapeutic purposes in the future.
49
Gad, Hend A., Fawzia A. Alshubaily, Mohammed A. Alsieni, Ahmed A. Tayel, and Amany M. Diab. "Biosynthesis of nano-curcumin/nano-selenium composite and their potentialities as bactericides against fish-borne pathogens." Green Processing and Synthesis 11, no. 1 (January 1, 2022): 1098–107. http://dx.doi.org/10.1515/gps-2022-0095.
Повний текст джерелаАнотація:
Abstract Fish-borne zoonotic bacteria can endanger the health of human and aquatic organisms; the nanobiotechnology applications can help. Curcumin nanoparticles (NC) were synthesized using gum Arabic (GA) and the resulted NC was innovatively employed for mediating selenium nanoparticles (NSe), then each compound/composite was evaluated as candidates for inhibiting fish-borne pathogens (Aeromonas hydrophila, Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus). The nanomaterials’ characterizations revealed the successfulness of their synthesis and conjugation. Promisingly, the NSe had particles’ diameter in the range of 2.4–15.8 nm and mean diameter of 6.1 nm, whereas the NC/NSe particles’ diameter was in the range of 15.4–92.3 nm and their mean diameter was 50.7 nm. The antibacterial activity of biosynthesized NC, NSe, and NC/NSe was validated quantitatively/qualitatively toward all examined bacteria; their powers were sorted as NC < NSe < NC/NSe. A. hydrophila was the most sensitive strain and S. aureus was the most resistant. The scan image of A. hydrophila cells exposed to NC/NSe indicated the high capability of nanocomposite to distort bacterial cells and lead them to death within 10 h of exposure. The biosynthesized NC, NSe, and NC/NSe are substantially advocated as natural biocides for controlling fish-borne zoonotic pathogens.
50
Graf, Jürgen, Michael Ruf, Holger Ott, Bruce Noll, Séverine Freisz, Alexander Gerisch, Birger Dittrich, Andreas Kleine, and Carsten Michaelsen. "Light-Atom Structures: Absolute Configuration Determination and Beyond." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C965. http://dx.doi.org/10.1107/s2053273314090342.
Повний текст джерелаАнотація:
The determination of the absolute configuration for light-atom structures is central to research in pharmaceuticals and natural-product synthesis [1]. In the absence of elements heavier than silicon, it is often problematic to make a significant assignment of absolute configuration. Traditionally, heavy-atom derivatives were prepared which have a stronger anomalous signal compared to the native compound. However, this is not always feasible. The assignment of the absolute structure of pure organic compounds has become somewhat easier with the advent of high-intensity microfocus sources [2], as the increased flux density improves the anomalous signal through improvements in counting statistics. In order to maximize the anomalous signal, X-ray sources with Cu anodes are usually used for the absolute structure determination. However, these data are usually limited to a maximum resolution of about 0.80 Å. High-brilliance microfocus X-ray sources with Mo targets enable the collection of high quality data beyond 0.40 Å within a reasonable amount of time. This allows not only a more accurate modelling of the electron density by using aspherical scattering factors, but also enables a reliable determination of the absolute structure, despite the significantly lower anomalous signal obtained with Mo Kα radiation. With the recently introduced liquid-Gallium-jet X-ray source unprecedented beam intensities can be achieved [3]. The shorter wavelength of Ga Kα compared to Cu Kα slightly weakens the anomalous signal of a typical light-atom structure. However, due to the shorter wavelength, the highest resolution for the liquid metal-jet source is typically at about 0.70 Å, compared to about 0.80 Å for Cu Kα. Hence, about 50% more unique reflections can be recorded. This clearly improves the structural model and the quality of the Flack parameter. Selected results on the absolute structure and charge density determinations for light-atom structures will be presented.