182 results on '"Carbon chain"'
Search Results
2. Study of enhanced gasification of biochar by non-thermal concentrating solar power using novel high-flux solar simulator thermogravimetric analyzer system
- Author
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Zhao, Deng, Wu, Tianyu, Wang, Jiantao, Ling, Shuo, Wang, Huashan, Liu, Hua, Liu, Hui, Guo, Shuai, and Wei, Xiudong
- Published
- 2025
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3. Carbon chain, hydroxyl and carbonyl: Potential drivers of nitrogen removal enhancement and nitrous oxide emissions in constructed wetlands
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Gu, Xushun, Sun, Shanshan, Zhang, Manping, Bai, Xiaohui, and He, Shengbing
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- 2025
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4. Microscopic molecular insights of different carbon chain fatty acids on shape-stabilized phase change composite.
- Author
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Ishak, Shafiq, Mandal, Soumen, Lgaz, Hassane, Atinafu, Dimberu G., Mohammad Harmay, Nurul Syahira, Lee, Han-Seung, Abdul Shukor Lim, Norhasanah, Abdullah, Mohd Mustafa Al Bakri, and Yang, Hyun-Min
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PHASE transitions , *HEAT storage , *CARBON composites , *DECANOIC acid , *STEARIC acid - Abstract
Biochar-based composite phase change materials (PCMs) are gaining popularity in thermal energy storage (TES) applications. Organic PCMs derived from fatty acids are favored for their affordability and variable melting temperatures based on carbon chain length. Understanding the interaction between different carbon-length fatty acid PCMs and porous biochar is crucial for optimizing thermal performance. Thus, this study explored the interaction between PCMs of decanoic acid (DA) and octadecanoic acid (OA) with banana peel (BP) biochar. Experimental results showed that shorter carbon chain of DA enhanced thermal properties and surface compactness compared to OA. BP-DA had higher loading efficiency and PCMs ratio, resulting in superior thermal cycle endurance and latent heat ratio. The molecular dynamics suggest that longer carbon chains affect the mean square displacement (MSD) curves, reducing the self-diffusion coefficients of BP-DA. This is due to DA's high loading rate, which occupies more space within BP biochar structure, thus limiting its diffusion capacity. Enhanced hydrogen bonding constrained DA's thermal motion during phase transition, restricting atom mobility within BP. With temperature elevations, BP-DA exhibits lesser fractional free volume than BP-OA, due to lower molecular mass. This research highlights how carbon chain length influences composite PCMs performance, offering insights for efficient TES system design. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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5. Exploring the Odd–Even Effect, Current Stabilization, and Negative Differential Resistance in Carbon-Chain-Based Molecular Devices.
- Author
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Wang, Lijun, Zhou, Liping, Wang, Xuefeng, and You, Wenlong
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CARBON nanofibers ,GREEN'S functions ,OHMIC contacts ,DENSITY functional theory ,DENSITY of states - Abstract
The transport properties of molecular devices based on carbon chains are systematically investigated using a combination of non-equilibrium Green's function (NEGF) and density functional theory (DFT) first-principle methods. In single-carbon-chain molecular devices, a distinct even–odd behavior of the current emerges, primarily influenced by the density of states (DOS) within the chain channel. Additionally, linear, monotonic currents exhibit Ohmic contact characteristics. In ladder-shaped carbon-chain molecular devices, a notable current stabilization behavior is observed, suggesting their potential utility as current stabilizers within circuits. We provide a comprehensive analysis of the transport properties of molecular devices featuring ladder-shaped carbon chains connecting benzene-ring molecules. The occurrence of negative differential resistance (NDR) in the low-bias voltage region is noted, with the possibility of manipulation by adjusting the position of the benzene-ring molecule. These findings offer a novel perspective on the potential applications of atom chains. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Overview of the Metallization Approaches for Carbyne-Based Devices.
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Tomov, Rade and Aleksandrova, Mariya
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METALLIC films , *ADHESIVES , *ATOMS - Abstract
Metallization for contacts in organic electronic nanodevices is of great importance for their performance. A lot of effects can appear at the contact/organic interface and modify the contact parameters, such as contact resistance, adhesive strength, and bonding ability. For novel materials, it is important to study the interactions with metal atoms to develop a suitable technology for contacts, fulfilling to the greatest extent the above-mentioned parameters. A novel material is carbyne, which is still under intensive research because of its great potential in electronics, especially for sensing applications. However, the most appropriate metallization strategy for carbyne-based devices is still unknown, so the interactions between carbyne and metal films should be studied to more precisely direct the development of the metallization technology, and to form contacts that are not limiting factors for device performance. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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7. Spatial variations and vertical migration potentials of petroleum hydrocarbons with varying chain lengths in soils of different depths: Roles of solid and dissolved organic matters and soil texture.
- Author
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Shu, Aiai, Yang, Zhenglun, Cui, Qianqian, Liu, Zhaoyang, Liu, Shun, Zhang, Mancheng, Sun, Heyang, Shang, Jiaqi, Tian, Huirui, Xiao, Yuting, and Tan, Wenfeng
- Published
- 2024
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8. Research on the construction of product carbon chain in supply chain and calculation of carbon footprint based on discriminant factors.
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Song, Jinyu, Li, Renwang, Guo, Lei, Wu, Xinli, and Liu, Haixia
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ECOLOGICAL impact , *SUPPLY chains , *ELECTRIC meters , *CARBON , *CARBONIZATION - Abstract
In the supply chain environment, the collection of carbon footprint data and quantitative descriptions is important for optimizing the related carbon footprint for products in order to find a low carbon production route for the products and to develop a low carbon supply chain. In this paper, by combining the life cycle method and the input-output method, a carbon footprint calculation model based on the discriminant factor is put forward. The three-phase electric meter was selected as an example. A carbon chain model was established in order to calculate the carbon footprint, which established a quantitative description for the low carbon supply chain and provided a new idea and method for the low carbonization of the supply chain. [ABSTRACT FROM AUTHOR]
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- 2020
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9. Effect of the Sintering Process on the Structure, Colorimetric, Optical and Photoluminescence Properties of SrWO4 Phosphor Powders.
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Wang, Shifa, Gao, Huajing, Wang, Yong, Sun, Guangzhuang, Zhao, Xinxin, Liu, Hufeng, Chen, Chaoli, and Yang, Liang
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OPTICAL properties ,POWDERS ,SINTERING ,SURFACE morphology ,FUNCTIONAL groups ,PHOSPHORS ,OTOACOUSTIC emissions - Abstract
Scheelite-type strontium tungstate (SrWO
4 ) phosphor powders were successfully synthesized using strontium nitrate and tungstic acid as starting materials by a gamma-ray irradiation-assisted polyacrylamide gel route. The phase purity, structure, functional groups, surface morphology, chemical composition, colorimetric, optical and photoluminescence properties of SrWO4 phosphor powders were systematically studied by various testing instruments. The crystallite size of SrWO4 phosphor powders increases with the increasing of sintering temperature. The color, optical and photoluminescence properties of SrWO4 phosphor powders are strongly dependent on the sintering temperature, carbon chain and the distortion of tetrahedral [WO4 ] clusters. The fluorescence emission at (310Â nm, 338Â nm, 360Â nm and 400Â nm) and 465Â nm can be ascribed to the new energy level formed by a carbon chain, amorphous SrWO4 or oxygen vacancy, and the distortion of tetrahedral [WO4 ] clusters, respectively. [ABSTRACT FROM AUTHOR]- Published
- 2020
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10. Dynamics of transfer of electron excitation in a donor-acceptor system with a carbon chain and ways of its relaxation
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M.M. Sevryukova and Yu.P. Piryatinsky
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merocyanines ,photoluminescence ,time-resolved emission spectra ,charge transfer ,donor-acceptor system ,carbon chain ,Physics ,QC1-999 - Abstract
The optical properties and dynamics of transport of electron excitation and the ways of its relaxation in the supramolecular D–π–A complex on the basis of merocyanines have been investigated. There have been found two components in the transfer of charge: fast and slow, which correspond to different conformational states of the carbon chain in merocyanines. It was found that the main photoluminescence of the studied molecular solutions of merocyanines by its nature is similar to the exciplex luminescence, as a manifestation of resonant and charge transfer interaction in an excited state. The lifetime in this state is about 2000 ps.
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- 2017
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11. Carbon nanobracelets.
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Vyrko, Sergey A., Polynskaya, Yulia G., Matsokin, Nikita A., Popov, Andrey M., Knizhnik, Andrey A., Poklonski, Nikolai A., and Lozovik, Yurii E.
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HYDROGEN atom , *ODD numbers , *ELECTRON density , *DENSITY functional theory , *CHEMICAL bond lengths , *CARBON - Abstract
Carbon-based cyclic molecules with alternating polycyclic regions and double carbon chains referred to as carbon nanobracelets are studied using spin-polarized density functional theory (DFT) calculations with PBE functional. Optimized structure of considered nanobracelets consisting of 1–5 identical monomers with and without hydrogen atoms at the edge of polycyclic regions is found to have highest possible symmetry and bond length alternation in chains. Nanobracelets consisting of odd number of monomers have lower HOMO energy, greater HOMO-LUMO gap and greater bond length variation in the carbon atomic chains than nanobracelets with even number of monomers. [Display omitted] • Cyclic molecules with alternate aromatic regions and double carbon chains are studied. • Alternation of short and long bond in chains of carbon nanobracelets is observed. • All considered carbon nanobracelets have the highest possible symmetry. • Difference in properties of nanobracelets with even and odd monomer number is found. • Hydrogen at aromatic region enhances the redistribution of electron density within monomer. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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12. Polyisoprenoid Distribution in Stems and Leaves of Pinus Merkusii Strains
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Rizka Amelia, Nur Indah Lestari, and Mohammad Basyuni
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Carbon chain ,Technology ,Physics and Astronomy (miscellaneous) ,biology ,General Mathematics ,Science ,Pinus merkusii ,General Chemistry ,biology.organism_classification ,chemistry.chemical_compound ,Polyprenol ,Dolichol ,chemistry ,Botany ,Pharmacology, Toxicology and Pharmaceutics (miscellaneous) - Abstract
Living things produce secondary metabolites, one of which is abundant in plants, namely polyisoprenoid alcohol compounds. Polyisoprenoids are also found in plants with different chain lengths. The distribution of polyisoprenoid compounds (dolichol and polyprenol) was found in the leaf and stem tissues of Pinus merkusii strains derived from Aceh, Tapanuli and Kerinci. The extracted samples were analyzed by the two-dimensional thin-layer chromatography (2D-TLC) method. The distribution of dolichol and polyprenol compounds on the stems and leaves of Aceh, Tapanuli and Kerinci pines provided a type II categorization, both dolichol and polyprenol were traced in pine tissues. Total lipids in stem tissue ranged from 564.4-58.9 mg/g dw, polyisoprenoid values ranged from 1.34-2.44 mg/g dw. In the leaves, total lipids ranged from 590 to 669.43 mg/g dw while polyisoprenoid values ranged from 1.29 to 5.70 mg/g dw. The dolichol carbon chain length in the Pine stem of strain composed C70-C90, C65-C90, and C65-C95. Meanwhile, carbon chain-length of C85-C105, C70-C95, and C50-C65 were found in leaf tissues. The length of the polyprenol carbon chain in the stem was C60-C90, C50-C90, and C70-C90 respectively, while the chain lengths on the leaves were C60-C115, C50-C95, and C30-C90. The present study suggested the presence of both dolichol and polyprenols in Pinus merkusii without predomination either dolichol or polyprenol.
- Published
- 2021
13. Size dependence of electronic spectrum for H-capped carbon chains, H-(C[tbnd]C)n-H (n = 3–9, 15): Analysis of its nature and prediction for carbyne.
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Wang, Jiaojiao, Dong, Chang, Liu, Zeyu, Zhou, Qing, Lu, Tian, Wang, Xia, Yan, Xiufen, Zhao, Mengdi, and Yuan, Aihua
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ELECTRONIC spectra ,INTRAMOLECULAR proton transfer reactions ,ELECTRONIC excitation ,OSCILLATOR strengths ,DENSITY functional theory ,CARBON ,FULLERENES - Abstract
[Display omitted] • Calculated geometric parameters and vertical excitation energy are perfectly consistent with the known experimental observations. • Size dependence of electronic and optical characteristics is explained by wavefunction analysis. • Extrapolation formulas of HOMO-LUMO gap, absorption wavelength, and oscillator strength have been drawn up for chains. • Suggested extrapolation formulas allow estimating the behavior of the electronic and optical properties for increasing chain length. The electronic spectrum of carbon chains has not been well understood in nature and deserves further study. In the present work, (time-dependent) density functional theory [(TD-)DFT] was employed to investigate the geometric and electronic structures as well as the allowed 1
1 Σ u+ ← X1 Σ g+ electronic transition of the H-capped carbon chains H-(C C) n -H (n = 3–9). The calculated geometric parameters and vertical excitation energy are perfectly consistent with the known experimental observations. The size dependence of electronic and optical characteristics in carbon chains is explained in depth by wavefunction analysis for electronic excitation and paid special attention to through data fitting and extrapolation, whose accuracy is confirmed by the specified species with n = 15. The suggested extrapolation formulas allow estimating the behavior of the electronic and optical properties for increasing chain length and even obtaining the limit values for sp -hybridized carbon allotrope carbine. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
14. 17α-hydroxylase/17,20 carbon chain lyase deficiency caused by p.Tyr329fs homozygous mutation: Three case reports
- Author
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Mao Zheng, Jianran Sun, Dai Zhang, Shandong Ye, Yan Xing, Jie Zhu, and Jiang Xu
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Carbon chain ,business.industry ,General Medicine ,Molecular biology ,Phenotype ,Lyase deficiency ,Cytochrome P450c17 ,03 medical and health sciences ,0302 clinical medicine ,030220 oncology & carcinogenesis ,Mutation (genetic algorithm) ,Mutation ,Case report ,Medicine ,030211 gastroenterology & hepatology ,17-α-hydroxylase-17,20-lyase deficiency ,business - Abstract
BACKGROUND p.Tyr329fs is a cytochrome P450c17 mutation among Chinese individuals. However, data on 17-α-hydroxylase deficiency caused by cytochrome P450c17 p.Tyr329fs homozygous mutation are lacking. This paper is a case report of three patients homozygous for p.Tyr329fs who were diagnosed with 17-α-hydroxylase deficiency between 2005 and 2019. CASE SUMMARY Case 1 presented with hypertension, hypokalemia, sexual infantilism and delayed bone age. The patient had a 46, XY karyotype, was homozygous for p.Tyr329fs and was recently treated with dexamethasone 0.375 mg qn. Case 2 presented with hypokalemia, sexual infantilism, osteoporosis and delayed bone age. The patient had a 46, XY karyotype, was homozygous for p.Tyr329fs and was treated with dexamethasone 0.75 mg qn at the last follow-up. Serum potassium and blood pressure could be maintained within normal range for cases 1 and 2. Case 3 presented with amenorrhea, sexual infantilism, osteopenia and delayed bone age. The patient had a 46, XX karyotype, was homozygous for p.Tyr329fs and was treated with dexamethasone 0.75 mg qn and progynova 1 mg qd. Outpatient follow-up revealed an adrenocorticotropic hormone (8 AM) of < 5.00 pg/mL. CONCLUSION The homozygous p.Tyr329fs mutation usually manifests as a combined deficiency, and definitive diagnosis depends primarily on genetic testing.
- Published
- 2021
15. Novel immunochromatographic assay based on Eu (III)-doped polystyrene nanoparticle-linker-monoclonal antibody for sensitive detection of Escherichia coli O157:H7.
- Author
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Xing, Ke-Yu, Peng, Juan, Liu, Dao-Feng, Hu, Li-Ming, Wang, Chun, Li, Guo-Qiang, Zhang, Gang-Gang, Huang, Zhen, Cheng, Song, Zhu, Fang-Fei, Liu, Na-Mei, and Lai, Wei-Hua
- Subjects
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EUROPIUM , *POLYSTYRENE , *NANOPARTICLES , *ESCHERICHIA coli identification , *MONOCLONAL antibodies - Abstract
Colloidal gold immunochromatographic assay (ICA) has poor sensitivity when used for Escherichia coli O157:H7 ( E. coli O157:H7) detection. Eu (III)-doped polystyrene nanoparticle (EuNP) has a large range of stokes shift, long decay time, and wide excitation spectrum and narrow emission spectra. EuNP has been used as novel probe in ICA to improve sensitivity. In this study, carboxyl-modified EuNPs were prepared with different linkers. ICA based on EuNP, EuNP-6 carbon chain (CC) complex, EuNP-200CC complex, EuNP-1000CC complex, and EuNP-streptavidin (EuNP-SA) complex were systematically compared for the detection of E. coli O157:H7. Under optimized working conditions, the limits of detection (LOD) of EuNP-ICA, EuNP-6CC-ICA, EuNP-200CC-ICA, EuNP-1000CC-ICA, and EuNP-SA-ICA were 9.54 × 10 2 , 1.59 × 10 2 , 3.18 × 10 2 , 2.98 × 10 2 , and 1.08 × 10 2 colony-forming units (CFU) mL −1 , respectively. The linear ranges of EuNP-ICA, EuNP-6CC-ICA, EuNP-200CC-ICA, EuNP-1000CC-ICA, and EuNP-SA-ICA were 6.36 × 10 2 –1.59 × 10 5 , 3.18 × 10 2 –1.59 × 10 5 , 6.36 × 10 2 –1.59 × 10 5 , 6.36 × 10 2 –1.59 × 10 5 , and 8.0 × 10 1 –1.59 × 10 5 CFU mL −1 , respectively. EuNP-SA-ICA exhibited the highest sensitivity and the widest linear range with good specificity, accuracy, and precision. It could be a promising analytical method for detecting E. coli O157:H7 in food samples. EuNP-SA-ICA may be a good model for detecting low concentrations of other food-borne pathogens. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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16. Dynamics of transfer of electron excitation in a donor-acceptor system with a carbon chain and ways of its relaxation.
- Author
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Sevryukova, M. M. and Piryatinsky, Yu. P.
- Subjects
CARBON ,CHARGE exchange ,ELECTRON donor-acceptor complexes ,SUPRAMOLECULAR chemistry ,SOLUTION (Chemistry) ,EXCITED states - Abstract
The optical properties and dynamics of transport of electron excitation and the ways of its relaxation in the supramolecular D-π-A complex on the basis of merocyanines have been investigated. There have been found two components in the transfer of charge: fast and slow, which correspond to different conformational states of the carbon chain in merocyanines. It was found that the main photoluminescence of the studied molecular solutions of merocyanines by its nature is similar to the exciplex luminescence, as a manifestation of resonant and charge transfer interaction in an excited state. The lifetime in this state is about 2000 ps. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
17. Theoretical studies of mixed-valence organometallic species for potential utilization as quantum cellular automata.
- Author
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Groizard, Thomas, Kahlal, Samia, and Halet, Jean-François
- Subjects
- *
ORGANOMETALLIC chemistry , *CELLULAR automata , *PHYSICAL & theoretical chemistry , *MOLECULAR electronics , *OXIDATION-reduction reaction - Abstract
The chemistry of mixed-valence complexes joins that of molecular electronics in the quantum cellular automata (QCA) paradigm, a concept which has been demonstrated to be a possible alternative to the transistor-based technology, in which binary information is encoded in the configuration of charge among redox-active molecular sites. Experimental and theoretical efforts have recently been devoted to molecular mixed-valence organometallic systems containing two and four metal centers as candidates for QCA. Properties of specific examples based on hypothetical organometallic molecules are theoretically analyzed and discussed with the aid of DFT calculations. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
18. The Vibration of a Linear Carbon Chain in Carbon Nanotubes.
- Author
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Dongqing Ding, Yang Zhao, Shuhong Dong, Peishi Yu, Liqiang Wang, and Junhua Zhao
- Subjects
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CARBON nanotubes , *VIBRATION (Mechanics) , *VAN der Waals forces , *FREQUENCIES of oscillating systems , *MOLECULAR dynamics , *NANOELECTROMECHANICAL systems - Abstract
An explicit solution for the vibration of a carbon chain inside carbon nanotubes (CNTs) was obtained using continuum modeling of the van der Waals (vdW) interactions between them. The effect of the initial tensile force and the amplitude of the carbon chain as well as the radii of the CNTs on the vibration frequency were analyzed in detail, respectively. Our analytical results show that the vibration frequency of the carbon chain in a (5,5) CNT could be around two orders of magnitude higher than that of an independent carbon chain without initial tensile force. For a given CNT radius, the vibration frequency nonlinearly increases with increasing amplitude and initial tensile force. The obtained analytical cohesive energy and vibration frequency are reasonable by comparison of present molecular dynamics (MD) simulations. These findings will be a great help towards understanding the vibration property of a nanowire in nanotubes, and designing nanoelectromechanical devices. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
19. Mechanism of Ultrasonic Physical–Chemical Viscosity Reduction for Different Heavy Oils
- Author
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Jing Liu, Fukang Yang, Feipeng Wu, Xia Junyong, and Chunsheng Pu
- Subjects
Carbon chain ,Materials science ,General Chemical Engineering ,Analytical chemistry ,General Chemistry ,Article ,Viscosity ,Chemistry ,Cavitation ,Physical chemical ,Ultrasonic sensor ,Gas chromatography ,Water content ,QD1-999 ,Asphaltene - Abstract
In this study, the mechanism of physical-chemical viscosity reduction of different heavy oils under ultrasonic wave is explored. Experiments of viscosity reduction and viscosity recovery of different heavy oils under ultrasonic excitation were carried out, and the optimal ultrasonic parameters, ultrasonic physical disturbance, and cavitation viscosity reduction extent of different oil samples were determined. Based on the element analysis methods, four-component analysis, gas chromatography analysis, and formation water pH value test, the micro-mechanism of the oil chemical structure change and water samples under ultrasonic wave was analyzed. The results show that the water content, temperature, and initial viscosity of heavy oil are the key to reduce the viscosity of heavy oil. The higher viscosity of the initial oil sample, the higher water content, and the temperature were needed. Compared with the lower viscosity oil sample, the higher viscosity oil sample has higher extent of cavitation viscosity reduction and lower extent of physical disturbance viscosity reduction under ultrasonic wave. After ultrasonic treatment, the contents of heteroatoms, resins, and asphaltenes in heavy oil samples with high viscosity decreased significantly, and the conversion extent of high carbon chain to low carbon chain was greater. In addition, the pH of water in heavy oils decreased after ultrasonic treatment, and the pH of water in high viscosity heavy oil decreased more significantly after ultrasonic treatment.
- Published
- 2021
20. The Long-Term Effect of Medically Enhancing Melanin Intrinsic Bioenergetics Capacity in Prematurity
- Author
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Lyudmila M. Mikhaleva, Siva G Somasundaram, Gjumrakch Aliev, Cecil E Kirkland, Vladimir N. Chubarev, Luis Fernando Torres Bernal, Paola Eugenia Solís Arias, Vadim V. Tarasov, Nina N. Minyaeva, Vladimir P. Fisenko, Andrey D. Bondarev, María del Carmen Arias Esparza, and Arturo Solís Herrera
- Subjects
retina ,Bioenergetics ,Article ,Melanin ,03 medical and health sciences ,0302 clinical medicine ,Dual role ,Drug Discovery ,Genetics ,retinopathy of prematurity ,Term effect ,Genetics (clinical) ,Carbon chain ,Metabolic energy ,Chemistry ,Hydrogen molecule ,prematurity ,General Medicine ,hydrogen ,030221 ophthalmology & optometry ,Biochemical engineering ,Energy source ,oxygen ,030217 neurology & neurosurgery ,energy - Abstract
Background: The ability of the human body to produce metabolic energy from light modifies fundamental concepts of biochemistry. Objective: This review discusses the relationships between the long-accepted concept is that glucose has a unique dual role as an energy source and as the main source of carbon chains that are precursors of all organic matter. The capability of melanin to produce energy challenges this premise. Methods: The prevalent biochemical concept, therefore, needs to be adjusted to incorporate a newly discovered state of Nature based on melanin’s ability to dissociate water to produce energy and to reform water from molecular hydrogen and oxygen. Results and Discussion: Our findings regarding the potential implication of QIAPI-1 as a melanin precursor that has bioenergetics capabilities. Conclusion: Specifically, we reported its promising application as a means for treating retinopathy of prematurity (ROP). The instant report focuses on the long-term treatment medical effects of melanin in treating ROP.
- Published
- 2020
21. TAO-DFT investigation of electronic properties of linear and cyclic carbon chains
- Author
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Jeng-Da Chai and S. Seenithurai
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0301 basic medicine ,Computational chemistry ,Electronic structure ,Materials science ,Chemical physics ,chemistry.chemical_element ,lcsh:Medicine ,Article ,Theoretical chemistry ,03 medical and health sciences ,Delocalized electron ,0302 clinical medicine ,Atomic orbital ,Nanoscience and technology ,lcsh:Science ,Electronic properties ,Theory and computation ,Carbon chain ,Nanoscale materials ,Multidisciplinary ,Nanowires ,Oscillation ,lcsh:R ,Chemistry ,Crystallography ,030104 developmental biology ,chemistry ,Density functional theory ,lcsh:Q ,Quantum chemistry ,Carbon ,030217 neurology & neurosurgery - Abstract
It has been challenging to adequately investigate the properties of nanosystems with radical nature using conventional electronic structure methods. We address this challenge by calculating the electronic properties of linear carbon chains (l-CC[n]) and cyclic carbon chains (c-CC[n]) with n = 10–100 carbon atoms, using thermally-assisted-occupation density functional theory (TAO-DFT). For all the cases investigated, l-CC[n]/c-CC[n] are ground-state singlets, and c-CC[n] are energetically more stable than l-CC[n]. The electronic properties of l-CC[n]/c-CC[n] reveal certain oscillation patterns for smaller n, followed by monotonic changes for larger n. For the smaller carbon chains, odd-numbered l-CC[n] are more stable than the adjacent even-numbered ones; c-CC[$$4m+2$$4m+2]/c-CC[4m] are more/less stable than the adjacent odd-numbered ones, where m are positive integers. As n increases, l-CC[n]/c-CC[n] possess increasing polyradical nature in their ground states, where the active orbitals are delocalized over the entire length of l-CC[n] or the whole circumference of c-CC[n].
- Published
- 2020
- Full Text
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22. Spatial variation of short- and medium-chain chlorinated paraffins in ambient air across Australia
- Author
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Louise M. van Mourik, Xianyu Wang, Jacob de Boer, Frank Wania, Chris Paxman, Jochen F. Mueller, Pim E.G. Leonards, E&H: Environmental Bioanalytical Chemistry, AIMMS, E&H: Environmental Chemistry and Toxicology, and Amsterdam Sustainability Institute
- Subjects
China ,010504 meteorology & atmospheric sciences ,Monitoring ,Health, Toxicology and Mutagenesis ,Antarctic Regions ,010501 environmental sciences ,Toxicology ,complex mixtures ,01 natural sciences ,Chlorinated paraffins ,Hydrocarbons, Chlorinated ,Humans ,0105 earth and related environmental sciences ,Carbon chain ,Polychlorinated n-alkanes (PCAs) ,Atmosphere ,Air ,Australia ,General Medicine ,Pollution ,Ambient air ,Paraffin ,Environmental chemistry ,Chlorinated paraffins (CPs) ,Environmental science ,Spatial variability ,Environmental Monitoring - Abstract
Atmospheric levels of chlorinated paraffins (CPs) at five remote, six rural and four urban sites in Australia were measured using XAD-2 passive air samplers (XAD-PAS). While long-chain CP (LCCP, C>17) levels were below method detection limits (MDLs), short-chain CPs (SCCPs, C10-13) and, for the first time, medium-chain CPs (MCCPs, C14-17) and CPs with a carbon chain length of nine (CP–C9) were found at many sites (88%, 81% and 88%, respectively) across the Australian continent, representing a range of environmental conditions. Applying preliminary sampling rates of the XAD-PAS for CPs, gaseous CP levels in Australian air were 3 for ΣSCCPs and ΣMCCPs, respectively, with a significant decreasing trend from more densely to less densely populated areas. Atmospheric median levels in this study (0.37 and 0.47 ng/m3 for SCCPs and MCCPs, respectively) were at the lower end of the median range (0.32–10 and 3.0–4.2 ng/m3 for SCCPs and MCCPs, respectively) reported for CPs at predominantly urban or industrial sites elsewhere (apart from China and extremely remote sites such as Antarctica). Principal component analysis matched the SCCP and MCCP congener group patterns in samples with those found in commercial mixtures, indicating a prevalence of less chlorinated congener groups in the Australian atmosphere. Information about the Australian production, use and disposal of CPs as well as their levels in other environmental matrices, including humans, is needed for assessing their emissions, behaviour, fate and potential exposure.
- Published
- 2020
- Full Text
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23. Effect of biodiesel ester structure optimization on low temperature performance and oxidation stability
- Author
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Fashe Li, Wenchao Wang, and Ying Li
- Subjects
lcsh:TN1-997 ,Materials science ,Cold filter plugging point ,Induction period ,Alcohol ,02 engineering and technology ,01 natural sciences ,Biomaterials ,chemistry.chemical_compound ,0103 physical sciences ,Organic chemistry ,Ethyl oleate ,lcsh:Mining engineering. Metallurgy ,010302 applied physics ,Carbon chain ,Biodiesel ,Metals and Alloys ,Oxidation stability ,Low-temperature performance ,Economy ,021001 nanoscience & nanotechnology ,Surfaces, Coatings and Films ,Oleic acid ,chemistry ,Ceramics and Composites ,Oleic acid-based esters ,0210 nano-technology - Abstract
The main shortcomings of biodiesel are related to the low-temperature performance and oxidation stability. Hence, this study proposes to investigate the influence of the oleic acid-based esters with various linear and branched chain alcohols on these two properties of biodiesel. The economic impact of biodiesel with various compositions is also evaluated by means of a mathematical model. The results showed that the longer the carbon chain length of the alcohol component, the better the low-temperature performance of the biodiesel. Hence, the cold filter plugging point and solidifying point of methyl oleate were −19 and −24 °C, respectively, whereas the cold filter plugging point and solidifying point of amyl oleate were −36 and −41 °C, respectively. The more irregular the molecular structure, the better the low-temperature performance of oleic acid-based lipids. For instance, the condensate point and solidifying point of oleic acid-based esters with branched chain alcohols should be lower than oleic acid-based esters with linear chain alcohols. On the other hand, for the linear esters of oleic acid, the oxidation stability is better as the carbon chain is longer. For instance, the induction period of methyl oleate is 0.07 h while for amyl oleate, it is 0.36 h, which corresponds to an increase of about 5 times. For the branched esters, although they are sensitive to oxidation, the induction period is higher than that of methyl oleate. Finally, the DEA evaluation model was used to analyze the economic aspects of the resulted biodiesel. The results showed that the addition of ethyl oleate to biodiesel significantly improved the low-temperature performance and oxidation stability of biodiesel with good economic benefits.
- Published
- 2020
24. On the relation between the strength and the plasticity of polymers.
- Author
-
Shtremel', M.
- Abstract
It is shown that the elongation to failure δ and ultimate tensile strength σ in polymers are related as σ(1 + δ) = s = const at the temperatures of non-Hookean entropy viscoelasticity. Different drawing from different initial states brings the structure of polymer to the limiting uniaxial structure with the same true stress of breaking carbon chains s . [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
25. Magnetism and spin transport of carbon chain between armchair graphene nanoribbon electrodes.
- Author
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Farghadan, R. and Yoosefi, M.
- Subjects
- *
MAGNETISM , *ELECTRIC properties of graphene , *NANORIBBONS , *FERMI energy , *SPIN polarization - Abstract
The magnetic and spin transport properties of a carbon chain between two armchair graphene nanoribbon (AGNR) electrodes were studied using tight-binding Hamiltonian, mean-field Hubbard model and Landauer–Butikker formalism. The results showed that only odd-numbered carbon chains show intrinsic magnetic moments in chain–graphene junctions. It was also found that the electronic, magnetic and spin transport properties of carbon chain–graphene junctions strongly depend on the position and the length of the carbon chains between AGNR electrodes. Interestingly, we found a fully spin-polarized transmission near the Fermi energy in all odd-numbered carbon chain–graphene junctions, regardless of their lengths and without any magnetic field and magnetic electrodes. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
26. Study on nitrogen doped carbon atom chains with negative differential resistance effect.
- Author
-
Shen, Ji-Mei, Liu, Jing, Min, Yi, and Zhou, Li-Ping
- Subjects
- *
ATOMIC number , *DENSITY functional theory , *NITROGEN absorption & adsorption , *DOPING agents (Chemistry) , *NON-equilibrium reactions , *GREEN'S functions , *DIPHENYL - Abstract
Recent calculations (Mahmoud and Lugli, 2013, [21] ) of gold leads sandwiching carbon chains which are separated by diphenyl–dimethyl demonstrated that the negative differential resistance (NDR) effect appears only for “odd” numbers of carbon atoms. In this paper, according to a first-principles study based on non-equilibrium Green's function combining density functional theory, we find that the NDR effect appears both for “odd” and for “even” numbers of carbon atoms when the chains are doped by nitrogen atom. Our calculations remove the restriction of “odd/even” chains for the NDR effect, which may promise the potential applications of carbon chains in the nano-scale or molecular devices in the future. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
27. Removal performances and mechanisms of action towards ethylenediaminetetraacetic acid nickel (II) salt by dithiocarbamate compounds having different carbon chain lengths.
- Author
-
Yan, Pingfang, Ye, Maoyou, Sun, Shuiyu, Xiao, Xiao, Dai, Wencan, and Zhang, Ning
- Subjects
- *
WASTEWATER treatment , *ETHYLENEDIAMINETETRAACETIC acid , *NICKEL , *DITHIOCARBAMATES , *METAL ions , *CARBON - Abstract
Wastewater containing EDTA-Ni (ethylenediaminetetraacetic acid nickel salt) must be treated due to its high toxicity, accumulation of nickel and non-degradability. In the present study, effect of carbon chain length of dithiocarbamate on the removal efficiency of Ni 2+ from an EDTA-Ni solution has been analyzed. Sodium dimethyl dithiocarbamate, sodium diethyl dithiocarbamate and sodium dibutyl dithiocarbamate were used to study their Ni 2+ removal performances from various types of EDTA-Ni solutions. Mechanisms of reactions between different dithiocarbamates and Ni 2+ were also studied. The results indicate that the rate of Ni 2+ increased with an increase in the carbon chain length of dithiocarbamate. Infrared spectral analysis inferred that the three dithiocarbamates had similar removal mechanisms despite having different carbon chain lengths: all showing Ni 2+ chelation. The thiol of dithiocarbamate captures Ni 2+ and tends to produce an insoluble chelate. The results from scanning electron microscope show that for longer carbon chain, the chelate product is more closely packed. Therefore, removed efficiency by sodium dibutyl dithiocarbamate was higher. Meanwhile coexistence of Cr 6+ , Cu 2+ and Fe 3+ inhibited the removal of Ni 2+ , but Zn 2+ promoted it. Metal ion impact became clearer as carbon chain length increased. The chelation capability of the three dithiocarbamates with metal ions was: Cr 6+ < Fe 3+ < Ni 2+ < Cu 2+ and Cu 2+ > Zn 2+ . Finally, these dithiocarbamates were tested in actual electroplating wastewater to validate our conclusions. After sodium dibutyl dithiocarbamate treatment, all residual metals' concentrations met the new tougher requirements announced by the Department of Environmental Protection of Guangdong province in Document No.25. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
28. Several Golgi targeting fluorescence markers based on 1,8-naphthalimide derivatives with amide and long carbon chain.
- Author
-
Feng, Xu-Chen, Zhang, Gang, Sun, Ru, Xu, Yu-Jie, and Ge, Jian-Feng
- Subjects
- *
GOLGI apparatus , *AMIDE derivatives , *FLUORESCENCE yield , *FLUORESCENCE , *CARBON compounds , *ENDOPLASMIC reticulum , *CARBON - Abstract
As an important organelle, the main function of the Golgi apparatus is to further modify and deliver proteins synthesized by the endoplasmic reticulum (ER). Dyshomeostasis of the Golgi appartus can cause many serious diseases. Therefore, monitoring the normal functioning of the Golgi appartus is particularly important. However, only a few commercially Golgi markers are available till now. In this work, three 1,8-naphthalimide related Golgi markers (4a - c) with the combination of amide and long carbon chain were designed and synthesized, their maximum emission wavelengths could reach 500–575 nm with high fluorescence quantum yields. Moreover, they possessed low cytotoxicity (cell viabilities >82%). Cell experiments exhibited that dyes 4a - c could rapidly and accurately mark the Golgi apparatus. To discuss the origin of their targeting ability, compounds 5–7 with independent amide or long carbon chain were additionally prepared. With the separation of amide and long carbon chain in compound 5 – 7 , the targeting ability was lost. The experiments showed that the targeting ability of 4a - c resulted from the combination of amide and long carbon chain structure. Also, the results may provide a new idea for designing organelle markers. [Display omitted] • Synthesis of three 1,8-naphthalimide derivatives with the combination of amide and long carbon chain. • All three dyes can quickly locate in the Golgi apparatus and not located to other organelles. • All three dyes can image at a low concentration. • The Golgi targeting ability may be attributed to the combination of amide and long carbon chain structure. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
29. Cardiometabolic impacts of saturated fatty acids: are they all comparable?
- Author
-
Aline Maria Nunes de Lira Gomes Bloise, João Henrique Costa-Silva, Aiany C. Simões-Alves, Alves Debora Santos, Béatrice Morio, Universidade Federal Rural de Pernambuco (UFRPE), Cardiovasculaire, métabolisme, diabétologie et nutrition (CarMeN), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Hospices Civils de Lyon (HCL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and CarMeN, laboratoire
- Subjects
obesity ,[SDV]Life Sciences [q-bio] ,030209 endocrinology & metabolism ,03 medical and health sciences ,0302 clinical medicine ,nutrition transition ,Environmental health ,medicine ,Nutrition transition ,Humans ,Saturated fatty acids ,Total energy ,030304 developmental biology ,2. Zero hunger ,Carbon chain ,0303 health sciences ,High prevalence ,business.industry ,Fatty Acids ,dyslipidemia ,food and beverages ,medicine.disease ,Food safety ,Dietary Fats ,Obesity ,Diet ,3. Good health ,[SDV] Life Sciences [q-bio] ,Cardiovascular Diseases ,cardiometabolic ,Energy Intake ,business ,Dyslipidemia ,Food Science - Abstract
International audience; In last decades, a phenomenon named nutrition transition has been observed in many countries around the world. It has been characterised by increased consumption of fat-rich diets, predisposing to cardiometabolic diseases and high prevalence of the obesity. In the dietary recommendations cited to prevent metabolic diseases, there is a consensus to decrease intake of saturated fatty acids (SFA) to less than 10% of total energy intake, as recommended by the Food Safety Authorities. However, fatty acids of different chain lengths may exhibit different cardiometabolic effects. Thus, our major aim was to review the cardiometabolic effects of different classes of SFA according to carbon chain length, i.e. short-, medium- and long-chains. The review emphasises that not all SFA may have harmful cardiometabolic effects since short- and medium-chain SFA can provide beneficial health effects and participate to the prevention of metabolic disorders.
- Published
- 2021
- Full Text
- View/download PDF
30. Densazalin, a New Cytotoxic Diazatricyclic Alkaloid from the Marine Sponge Haliclona densaspicula
- Author
-
Sangbum Lee, Yong Tae Jeong, Buyng Su Hwang, Eun Ju Jeong, and Jung-Rae Rho
- Subjects
Stereochemistry ,Pharmaceutical Science ,Organic chemistry ,010402 general chemistry ,Mass spectrometry ,01 natural sciences ,Analytical Chemistry ,Haliclona densaspicula ,QD241-441 ,Haliclona ,Drug Discovery ,Bioassay ,Cytotoxic T cell ,Moiety ,Physical and Theoretical Chemistry ,densazalin ,Carbon chain ,biology ,010405 organic chemistry ,Chemistry ,Alkaloid ,biology.organism_classification ,0104 chemical sciences ,Sponge ,Chemistry (miscellaneous) ,cytotoxic alkaloid ,Molecular Medicine ,1,3-alkylpyridine - Abstract
Densazalin, a polycyclic alkaloid, was isolated from the marine sponge Haliclona densaspicula collected in Korea. The complete structure of the compound was determined by spectroscopic methods, including 1D and 2D nuclear magnetic resonance techniques, high-resolution mass spectrometry, and comparison of the calculated and measured electronic circular dichroism spectra. Densazalin possesses a unique 5,11-diazatricyclo[7.3.1.02,7]tridecan-2,4,6-triene moiety, which is connected by two linear carbon chains. This compound was derived from the biogenetic precursor bis-1,3-dialkylpyridnium. Densazalin exhibited cytotoxic activity on two human tumor cell lines (AGS and HepG2) in the Cell Counting Kit-8 (CCK-8) bioassay, with IC50 values ranging from 15.5 to 18.4 μM.
- Published
- 2021
31. Optical and structural properties of cyanine dyes via electronic structure calculations
- Author
-
Augusto Batagin-Neto, C.F.O. Graeff, L.A. Galindo, O.P. Gomes, and Universidade Estadual Paulista (Unesp)
- Subjects
Carbon chain ,Electron density ,010304 chemical physics ,Chemistry ,Cationic polymerization ,Absorption spectra ,Nanotechnology ,Electronic structure ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,chemistry.chemical_compound ,Semi-empirical methods ,0103 physical sciences ,Density functional theory ,Physical and Theoretical Chemistry ,Cyanine ,Dyes - Abstract
Made available in DSpace on 2021-06-25T10:55:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Cyanine dyes are interesting compounds for diverse technological applications mainly because of their unique optoelectronic properties. Despite their interesting features, in general, structural and optical properties of these materials are not well described by electronic structure calculations. In this report distinct approaches and methods were used to evaluate structural and optical properties of a series of cyanine dyes to identify suitable methodologies. The results suggest that polymethine dyes can be properly modeled as cationic structures and non-conventional AM1/CIS and PM3/CIS approaches can describe the major optical features of these compounds, due a better description of the electron density on the carbon chains. Our data indicate very suitable and inexpensive approaches to investigate new cyanine dyes. São Paulo State University (UNESP) School of Sciences POSMAT São Paulo State University (UNESP) School of Sciences Department of Physics São Paulo State University (UNESP), Campus of Itapeva São Paulo State University (UNESP) School of Sciences POSMAT São Paulo State University (UNESP) School of Sciences Department of Physics São Paulo State University (UNESP), Campus of Itapeva CNPq: 420449/2018-3 CNPq: 448310/2014-7
- Published
- 2021
32. Ni/SiO2 catalyst prepared via Ni-aliphatic amine complexation for dry reforming of methane: Effect of carbon chain number and amine concentration.
- Author
-
Gao, X.Y., Ashok, J., Widjaja, S., Hidajat, K., and Kawi, S.
- Subjects
- *
NICKEL catalysts , *SILICA , *ALIPHATIC amines , *COMPLEXATION reactions , *METHANE , *NUCLEATION , *CHARGE exchange - Abstract
Aliphatic amines of different carbon numbers (i.e., carbon number in one linear hydrocarbon chain, N c ) and concentrations ( C a ) were used in the preparation of silicon dioxide (SiO 2 ) supported nickel catalysts by incipient wetness impregnation (IWI) method. The results showed that both the size and the metal-support interaction (MSI) were affected by the carbon chain number and the amine concentration. On one hand, the use of the aliphatic amine with a larger carbon chain number achieved a smaller size and higher dispersion due to the stronger steric hindrance; this smaller size and higher dispersion further enhanced the MSI because of the larger contact area of Ni with the silica support. On the other hand, a higher amine concentration decreases the size and improve the dispersion because of the faster nucleation rate; also when higher concentration of amine was used, more hydrogen bonds were formed between the -NH 2 and the silanol group and more electron transfer was found between Ni and the -NH 2 , leading to a stronger MSI. With a small size, high dispersion and strong MSI, NiSi-OAm showed the most stable catalytic performances (CO 2 conversion of 78% and CH 4 conversion of 70% within 20 h) with low carbon deposition (1.8 mgC/ g cat h) for dry reforming of methane (DRM) reaction. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
33. Energetic stability, atomic and electronic structures of extended γ-graphyne: A density functional study.
- Author
-
Baoqian Chi, Yi Liu, Xiaowu Li, Jingcheng Xu, Xuming Qin, Chen Sun, Chenghao Bai, and Xinluo Zhao
- Abstract
The energetic stability, atomic and electronic structures of γ-graphyne and its derivatives (γ-GYs) with extended carbon chains were investigated as a function of chain length by density functional calculations in this work. The studied γ-GYs consist of hexagon carbon rings connected by linear chains with C atoms n = 0-22. We predict that the even-numbered C chains of γ-GYs consist of alternating single and triple C-C bonds (polyyne), energetically more stable than the odd-numbered C chains made of continuous C-C double bonds (polycumulene). The calculated electronic structures indicate that γ-GYs can be either metallic (odd n) or semiconductive (even n) depending on the parity of the number of C chain atoms. The semiconducting γ-GYs are predicted to have ~1.2 eV direct band gaps and 0.1-0.2 effective electron masses independent of the chain length. Thus introducing sp carbon atoms into sp2-based graphene provides a novel way to open up band gaps without doping and defects while maintaining small electron masses critical to good transport properties. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
34. Electronic property and charge carrier mobility of extended nanowires built from narrow graphene nanoribbon and atomic carbon chain.
- Author
-
Zhu, Ying, Bai, Hongcun, and Huang, Yuanhe
- Subjects
- *
ELECTRIC properties of metals , *NANOWIRES , *ELECTRIC charge , *NANORIBBONS , *GRAPHENE , *CARBON compounds - Abstract
This work presented theoretical studies on the extended nanowires constructed from narrow graphene nanoribbons and atomic carbon chains by using self-consistent field crystal orbital method based on density functional theory. The size and connection effects on geometrical structure, relative stability and electronic property of these one-dimensional (1D) nanowires have been addressed systemically and in details. It is found that the ratio of narrow graphene nanoribbons and C C units may be the key factor to the relative thermodynamic stability of these 1D wires based on the obtained Gibbs free energy. All the extended nanowires studied have a direct band gap according to the calculated electronic band structures. The obtained band gaps of the nanowires are in the range of 0.918–2.015 eV. These flexible band gaps imply the possibility to modulate the electronic properties of these extended wires by turning the sizes and connections. Furthermore, a quantitative relation between the band gap and the ratio of phenylene and C C units is obtained. Moreover, we calculate the charge carrier mobility of the extended nanowires based on the deformation potential theory and effective mass approach. The frontier crystal orbital analyses are performed to get a better understanding of the charge carrier mobility for the 1D nanowires with various sizes and connections. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
35. Spin filtering behaviors for a carbon chain connected with armchair- and zigzag-edged graphene nanoribbon electrodes.
- Author
-
Yang, C.H., Deng, X.Q., Tang, G.P., and Fan, Z.Q.
- Subjects
- *
CARBON , *GRAPHENE , *NANORIBBONS , *ELECTRODES , *GREEN'S functions , *SPIN polarization - Abstract
Using the non-equilibrium Green’s function method combined with the density functional theory, we investigate the spin transport properties of carbon chains connected with armchair- and zigzag-edged graphene nanoribbon (ZGNR) electrodes at finite bias with the parallel magnetism configuration. When spin polarized electrons are injected into carbon chains from the ZGNR electrode, the β-spin current is nearly zero, while the α-spin current shows large values in the calculated bias region, thus the spin polarization 100% can be achieved, which is a promising pathway for developing a spin filter. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
36. Neutral-Neutral Synthesis of Organic Molecules in Cometary Comae
- Author
-
Martin A. Cordiner and Steven B. Charnley
- Subjects
Formamide ,Physics ,Carbon chain ,Earth and Planetary Astrophysics (astro-ph.EP) ,Astrochemistry ,010504 meteorology & atmospheric sciences ,Comet ,FOS: Physical sciences ,food and beverages ,Astronomy and Astrophysics ,01 natural sciences ,Submillimeter Array ,Astrobiology ,Organic molecules ,chemistry.chemical_compound ,chemistry ,Space and Planetary Science ,0103 physical sciences ,Cyanoacetylene ,Molecule ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Remote and in-situ observations of cometary gases have revealed the presence of a wealth of complex organic molecules, including carbon chains, alcohols, imines and the amino acid glycine. Such chemical complexity in cometary material implies that impacts by comets could have supplied reagents for prebiotic chemistry to young planetary surfaces. However, the assumption that some of the molecules observed in cometary comae at millimetre wavelengths originate from ices stored inside the nucleus has not yet been proven. In fact, the comae of moderately-active comets reach sufficient densities within a few thousand kilometers of the nucleus for an active (solar radiation-driven) photochemistry to ensue. Here we present results from our latest chemical-hydrodynamic models incorporating an updated reaction network, and show that the commonly-observed HC3N (cyanoacetylene) and NH2CHO (formamide) molecules can be efficiently produced in cometary comae as a result of two-body, neutral-neutral, gas-phase reactions involving well-known coma gases. In the presence of a near-nucleus distributed source of CN (similar to that observed by the Rosetta spacecraft at comet 67P), we find that sufficient HC$_3$N and NH2CHO can be synthesized to match the abundances of these molecules in previous observations of Oort Cloud comets. The precise origin of these (and other) complex organic molecules in cometary comae can be verified through interferometric mapping observations, for example, using the Atacama Large Millimeter/submillimeter Array (ALMA)., Accepted for publication in MNRAS, April 15th 2021
- Published
- 2021
37. The connection between warm carbon chain chemistry and interstellar irradiation of star-forming cores
- Author
-
Juris Kalvāns
- Subjects
Chemical Physics (physics.chem-ph) ,Physics ,Carbon chain ,Astrochemistry ,Star formation ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Cosmic ray ,Astrophysics ,Star (graph theory) ,Astrophysics - Astrophysics of Galaxies ,Connection (mathematics) ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Physics - Chemical Physics ,Astrophysics::Solar and Stellar Astrophysics ,Irradiation ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
Some observations of warm carbon chain chemistry (WCCC) cores indicate that they are often located near the edges of molecular clouds. This finding may suggest that WCCC is promoted in star-forming cores exposed to radiation from the interstellar medium. We aim to investigate the chemistry of carbon chains in such a core. A chemical simulation of a gas parcel in a low-mass star-forming core with a full level of irradiation by interstellar photons and cosmic rays was compared to a simulation of a core receiving only one-tenth of such irradiation. In the full irradiation model, the abundances of carbon chains were found to be higher by a factor of few to few hundred, compared to the model with low irradiation. Higher carbon-chain abundances in the prestellar stage and, presumably, in the extended circumstellar envelope, arise because of irradiation of gas and dust by interstellar photons and cosmic rays. A full standard rate of cosmic-ray induced ionization is essential for a high carbon-chain abundance peak to occur in the circumstellar envelope, which is heated by the protostar (the "true" WCCC phenomenon). The full irradiation model has lower abundances of complex organic molecules than the low-irradiation model. We conclude that WCCC can be caused by exposure of a star-forming core to interstellar radiation, or even just to cosmic rays. The Appendix describes an updated accurate approach for calculating the rate of cosmic-ray induced desorption., Accepted for publication in ApJ
- Published
- 2021
38. Linear carbon chain in the interior of a single walled carbon nanotube.
- Author
-
Zólyomi, Viktor, Ruszny&#x.00E1;k, Ádám, Kürti, Jenö, Shujiang Yang, and Kertesz, Miklos
- Subjects
- *
NANOTUBES , *CARBON , *DENSITY functionals , *SEMICONDUCTORS , *SIMULATION methods & models , *CHARGE transfer - Abstract
The physical properties of several kinds of single walled carbon nanotubes containing a single carbon chain in their interior are investigated with density functional theory, using the Vienna ab initio Simulation Package (VASP). The optimized geometry and the electronic band structure are both examined, and compared to the results of the isolated subsystems: the isolated carbon chain and the isolated nanotube. We find bondlength alternation in the optimized geometry of the isolated chain, as well as a gap in the band structure, clear signs of Peierls distortion. In the combined systems, hybridization and charge transfer are found between the tube and the chain, resulting in a partial or complete breakdown of the Peierls distortion of the carbon chain. The combined systems are always predicted to be metallic, even if both subsystems are semiconductors, and even if the chain still exhibits some bond length alternation. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
39. Bioelectricity-assisted partial degradation of linear polyacrylamide in a bioelectrochemical system.
- Author
-
Cui, Yu-Zhi, Zhang, Jian, Sun, Min, and Zhai, Lin-Feng
- Subjects
- *
ELECTROPHYSIOLOGY , *POLYACRYLAMIDE , *POLLUTION , *BIOLOGICAL nutrient removal , *BIODEGRADATION , *MOLECULAR weights , *PLANKTON - Abstract
The wide application of water-soluble linear polyacrylamides (PAMs) can cause serious environmental pollution. Biological treatment of PAMs receives very limited efficiency due to their recalcitrance to the microbial degradation. Here, we show the bioelectrochemical system (BES) can be used as an effective strategy to improve the biodegradation efficiency of PAMs. A linear PAM with viscosity-average molecular weight of 5 × 10 was treated in the anodic chamber of BES reactor, and the change of PAM structure during the degradation process was investigated. The anodic bacteria in the BES demonstrated abilities to utilize the PAM as the sole carbon and nitrogen source to generate electricity. Both the anode-attached and planktonic bacteria contributed to the electricity generation, while the anode-attached community exhibited stronger electron transfer ability than the planktonic one. The closed-circuit and open-circuit operations of the BES reactor obtained chemical oxygen demand (COD) removal efficiencies of 32.5 and 7.4 %, respectively, implying the generation of bioelectricity could enhance the biodegradation of PAM. Structure analysis suggested the carbon chain of PAM was partially degraded in the BES, producing polymeric products with lower molecular weight. The microbial cleavage of the carbon chain was proposed to start from the 'head-to-head' linkages and end with the formation of ether bonds. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
40. Effects of carbon chain on hole-transport properties in naphtho[2,1-b:6,5-b′]difuran derivatives: Remarkable anisotropic mobilities.
- Author
-
Zhang, Xiao-Yu, Zhao, Guang-Jiu, Huang, Jin-Dou, and Zhang, Wei-Ping
- Subjects
- *
FURAN derivatives , *ANISOTROPY , *ORGANIC semiconductors , *QUANTUM mechanics , *IONIZATION energy , *MOLECULAR orbitals - Abstract
Theoretical investigations of hole-transport properties in two naphtho[2,1-b:6,5-b′]difuran derivatives as novel p-type organic semiconductor based on the Marcus–Hush theory combining quantum mechanics are carried out. This work focuses on the effects of carbon chain on molecular orbitals, partial charge difference, ionization potential, internal energy relaxation, and hole-transport behaviors. Through computational modeling, we are shedding light on the favorable function of C8-DPNDF single crystal as p-type organic material. With the introduction of octyl group, C8-DPNDF single crystal possesses high hole-transfer mobilites (1.589 cm 2 V − 1 s − 1 ) and remarkable anisotropic behavior. The simulated anisotropic mobility curve of C8-DPNDF demonstrates the maximum value of the mobility appears when the measuring conducting channel is along the b -axis of the single crystal. The adiabatic ionization potential (AIP) and vertical ionization potential (VIP) of C8-DPNDF are about 6.312 and 6.399 eV, that is, slightly smaller than those of DPNDF. The relatively small IP values can ensure effective hole injection from the source electrode. The data obtained from the present work can be used to prove that C8-DPNDF molecule has the potential to develop into high-efficient p-type organic semiconductor materials, whose hole-transport mobility can be further improved when the measuring transistor channel is controlled carefully. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
41. A Polyol-Polyol Super-Carbon-Chain Compound Containing Thirty-Six Carbon Stereocenters from the Dinoflagellate Amphidinium gibbosum: Absolute Configuration and Multi-Segment Modification
- Author
-
Yi Yu, Zeng Luo, Yan-Lan Zhu, Jun Wu, Li Shen, and Wan-Shan Li
- Subjects
marine dinoflagellate ,super-carbon-chain compound ,Stereochemistry ,Polymers ,Pharmaceutical Science ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,Article ,Stereocenter ,multi-segment modification ,Polyol ,Drug Discovery ,Amphidinium gibbosum ,lcsh:QH301-705.5 ,Pharmacology, Toxicology and Pharmaceutics (miscellaneous) ,chemistry.chemical_classification ,Carbon chain ,biology ,Molecular Structure ,010405 organic chemistry ,Amphidinium ,Dinoflagellate ,Absolute configuration ,biology.organism_classification ,0104 chemical sciences ,NMR spectra database ,absolute configuration ,lcsh:Biology (General) ,chemistry ,Dinoflagellida ,Carbon - Abstract
A super-carbon-chain compound, named gibbosol C, featuring a polyoxygenated C70-linear-carbon-chain backbone encompassing two acyclic polyol chains, was obtained from the South China Sea dinoflagellate Amphidinium gibbosum. Its planar structure was elucidated by extensive NMR investigations, whereas its absolute configurations, featuring the presence of 36 carbon stereocenters and 30 hydroxy groups, were successfully established by comparison of NMR data of the ozonolyzed products with those of gibbosol A, combined with J-based configuration analysis, Kishi&rsquo, s universal NMR database, and the modified Mosher&rsquo, s MTPA ester method. Multi-segment modification was revealed as the smart biosynthetic strategy for the dinoflagellate to create remarkable super-carbon-chain compounds with structural diversity.
- Published
- 2020
42. A Comprehensive Understanding of Electro-Fermentation
- Author
-
Namita Khanna, Rishi Pramod Babu, Drishti Dinesh Bhagchandanii, Ram Prasad, Soumya Pandit, Santimoy Khilari, Dipak A. Jadhav, and Jayesh M. Sonawane
- Subjects
Microbial fuel cell ,microbial fuel cells ,Methanogenesis ,Industrial fermentation ,Plant Science ,010501 environmental sciences ,01 natural sciences ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,Redox ,electro fermentation ,03 medical and health sciences ,metabolic pathways ,030304 developmental biology ,0105 earth and related environmental sciences ,Carbon chain ,0303 health sciences ,lcsh:TP500-660 ,biology ,anaerobic fermentation ,Chemistry ,food and beverages ,bioelectrochemical system ,biology.organism_classification ,lcsh:Fermentation industries. Beverages. Alcohol ,Metabolic pathway ,Fermentation ,Biochemical engineering ,Bacteria ,Food Science - Abstract
Electro-fermentation (EF) is an upcoming technology that can control the metabolism of exoelectrogenic bacteria (i.e., bacteria that transfer electrons using an extracellular mechanism). The fermenter consists of electrodes that act as sink and source for the production and movement of electrons and protons, thus generating electricity and producing valuable products. The conventional process of fermentation has several drawbacks that restrict their application and economic viability. Additionally, metabolic reactions taking place in traditional fermenters are often redox imbalanced. Almost all metabolic pathways and microbial strains have been studied, and EF can electrochemically control this. The process of EF can be used to optimize metabolic processes taking place in the fermenter by controlling the redox and pH imbalances and by stimulating carbon chain elongation or breakdown to improve the overall biomass yield and support the production of a specific product. This review briefly discusses microbe-electrode interactions, electro-fermenter designs, mixed-culture EF, and pure culture EF in industrial applications, electro methanogenesis, and the various products that could be hence generated using this process.
- Published
- 2020
43. Is It Conjugated or Not? The Theoretical and Experimental Electron Density Map of Bonding in p-CH3CH2COC6H4-C≡C-C≡C-p-C6H4COCH3CH2
- Author
-
Sławomir Szafert, Karolina Osowska, Przemysław Starynowicz, Tadeusz Lis, Slawomir Berski, and Nurbey Gulia
- Subjects
Diffraction ,Carbon chain ,Electron density ,Materials science ,Mathematics::Number Theory ,Organic Chemistry ,Pharmaceutical Science ,Conjugated system ,polyynes ,Electron localization function ,Analytical Chemistry ,lcsh:QD241-441 ,Crystallography ,lcsh:Organic chemistry ,Chemistry (miscellaneous) ,Distortion ,density map ,electron localization function ,Drug Discovery ,Molecular Medicine ,Single bond ,single-crystal X-ray diffraction ,Physical and Theoretical Chemistry ,Electron distribution ,theoretical calculations - Abstract
The electron density of p-CH3CH2COC6H4-C&equiv, CC&equiv, C-p-C6H4COCH3CH2 has been investigated on the basis of single-crystal X-ray diffraction data collected to high resolution at 100 K and from theoretical calculations. An analysis of the X-ray data of the diyne showed interesting &ldquo, liquidity&rdquo, of electron distribution along the carbon chain compared to 1,2-diphenylacetylene. These findings are compatible with the results of topological analysis of Electron Localization Function (ELF), which has also revealed a larger (than expected) concentration of the electron density at the single bonds. Both methods indicate a clear &pi, type or &ldquo, banana&rdquo, character of a single bond and a significant distortion from the typical conjugated structure of the bonding in the diyne with a small contribution of cumulenic structures.
- Published
- 2020
44. Electrooxidation of C-4 polyols on platinum single- crystals: a computational and electrochemical study
- Author
-
Marc T. M. Koper, Pablo S. Fernández, Victor Y. Yukuhiro, Yuvraj Y. Birdja, José L. Bott-Neto, Cléo T. G. V. M. T. Pires, Carlos C. Lima, Cinthia R. Zanata, Miguel A. San-Miguel, and Gabriela Volpini Soffiati
- Subjects
Carbon chain ,Chemical substance ,Materials science ,Biomass ,chemistry.chemical_element ,02 engineering and technology ,Reaction intermediate ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,General Energy ,chemistry ,Chemical engineering ,Molecule ,Physical and Theoretical Chemistry ,0210 nano-technology ,Science, technology and society ,Platinum - Abstract
Many polyols are abundant and cheap molecules highly spread in the biomass. These molecules have an enormous potential to be used in electrochemical devices to generate energy and/or value-added molecules. The electrooxidation of polyols can produce different substances of interest in the chemical industry concomitantly to high purity hydrogen in electrolyzers. The cost in the production of all these chemicals depends, among other factors, on the develop of more active and selective catalysts. However, in order to search for these materials using computational experiments, it is mandatory to have a better understanding of the fundamental aspect of the reactions, which permit to base the search on the adsorption energies of one or more key reaction intermediates. To contribute to this task, we performed (spectro)-electrochemical and computational experiments to study the electrooxidation of C-4 polyols. We show that the electrooxidation of polyols does not depend on the relative orientation of their OH groups. Besides, using Pt single crystals, we demonstrate that the trend for the oxidation of the primary carbon (relative to the secondary) increases in the order Pt(111) < Pt(100) < Pt(110) and that this result can be extended to polyols with longer carbon chains. Finally, computational experiments permit us to rationalize these trends looking at the relative stability of double dehydrogenated intermediates on the Pt basal planes.
- Published
- 2020
45. G-Protein biased opioid agonists: 3-hydroxy-N-phenethyl-5-phenylmorphans with three-carbon chain substituents at C9
- Author
-
Sergio A. Hassan, Arthur E. Jacobson, Gregory H. Imler, Thomas E. Prisinzano, Kenner C. Rice, Eugene S. Gutman, Rachel Saylor Crowley, Eric W Bow, Agnieszka Sulima, Jeffrey R. Deschamps, Fuying Li, Yong-Sok Lee, and Sophia Kaska
- Subjects
0301 basic medicine ,Pharmacology ,Carbon chain ,G protein ,Stereochemistry ,Organic Chemistry ,Pharmaceutical Science ,Biochemistry ,In vitro ,03 medical and health sciences ,chemistry.chemical_compound ,Chemistry ,030104 developmental biology ,0302 clinical medicine ,chemistry ,Opioid ,Drug Discovery ,medicine ,Morphine ,Molecular Medicine ,Phenol ,Receptor ,030217 neurology & neurosurgery ,medicine.drug - Abstract
A series of compounds have been synthesized with a variety of substituents based on a three-carbon chain at the C9-position of 3-hydroxy-N-phenethyl-5-phenylmorphan (3-(2-phenethyl-2-azabicyclo[3.3.1]nonan-5-yl)phenol). Three of these were found to be μ-opioid receptor agonists in the inhibition of forskolin-induced cAMP accumulation assay and they did not recruit β-arrestin at all in the PathHunter assay and in the Tango assay. Compound 12 (3-((1S,5R,9R)-2-phenethyl-9-propyl-2-azabicyclo[3.3.1]nonan-5-yl)phenol), 13 (3-((1S,5R,9R)-9-((E)-3-hydroxyprop-1-en-1-yl)-2-phenethyl-2-azabicyclo[3.3.1]nonan-5-yl)phenol), and 15a (3-((1S,5R,9R)-9-(2-hydroxypropyl)-2-phenethyl-2-azabicyclo[3.3.1]nonan-5-yl)phenol) were partial μ-agonists. Two of them had moderate efficacies (E(MAX)ca. 65%) and one had lower efficacy, and they were ca. 5, 3, and 4 times more potent, respectively, than morphine in vitro. Computer simulations were carried out to provide a molecular basis for the high bias ratios of the C9-substituted 5-phenylmorphans toward G-protein activation.
- Published
- 2020
46. Correlation between UV resilience and wavelength of narrow diffuse interstellar bands
- Author
-
Holger F. Bettinger, Alain Omont, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut für Organische Chemie [Mainz] (IOC), and Johannes Gutenberg - Universität Mainz (JGU)
- Subjects
Physics ,Carbon chain ,Astrochemistry ,Diffuse interstellar band ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,Extinction (astronomy) ,fungi ,chemistry.chemical_element ,Astronomy and Astrophysics ,Astrophysics ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Wavelength ,chemistry ,Space and Planetary Science ,0103 physical sciences ,Band width ,Resilience (materials science) ,010303 astronomy & astrophysics ,Carbon - Abstract
Carriers of diffuse interstellar bands (DIBs) still need to be identified. In a recent paper, we reported a correlation between the DIB wavelength and the apparent UV resilience (or boost) of their carriers. We proposed that this might be an indication of the important role of conjugated elongated molecules among the DIB carriers. The aim of this paper is to further understand the origin of this correlation. The analysis of 509 optical DIBs on the lines of sight of HD 183143 and/or HD 204827 reported in the literature shows that this correlation mainly implies the 386 narrow DIBs with a band width 2andζfamilies, while the majority of the 123 broader DIBs, including the identifiedσDIBs, do not display such a correlation. We present a possible origin of this correlation from very strong bands of large conjugated elongated molecules, such as carbon chains, polyacenes, or other catacondensed polycyclic aromatic hydrocarbons. The total amount of carbon contained in all the carriers of these narrow DIBs is a very small fraction of the interstellar carbon if their oscillator strengths are ≥1. The amount of carbon locked in the carriers of the broader DIBs is higher, especially if their oscillator strengths are significantly weaker.
- Published
- 2020
- Full Text
- View/download PDF
47. Lactational Transfer of Long-Chain Perfluorinated Carboxylic Acids in Mice: A Method to Directly Collect Milk and Evaluate Chemical Transferability
- Author
-
Yukiko Fujii, Hatasu Kobayashi, Koichi Haraguchi, Akio Koizumi, and Kouji H. Harada
- Subjects
Health, Toxicology and Mutagenesis ,Transferability ,0211 other engineering and technologies ,02 engineering and technology ,010501 environmental sciences ,Breast milk ,Toxicology ,lcsh:Chemical technology ,01 natural sciences ,Article ,Milking ,chemistry.chemical_compound ,Animal science ,Lactation ,medicine ,lcsh:TP1-1185 ,perfluoroalkyl carboxylic acids ,0105 earth and related environmental sciences ,Carbon chain ,021110 strategic, defence & security studies ,Chemical Health and Safety ,Chemistry ,medicine.anatomical_structure ,Lipophilicity ,Perfluorooctanoic acid ,neonatal exposure ,intake estimation ,Long chain - Abstract
Perfluoroalkyl carboxylic acids (PFCAs), such as perfluorooctanoic acid (PFOA, C8), are a group of industrial chemicals that are detected in the serum of people throughout the world. Long-chain PFCAs (C9 to C13) have high lipophilicity, therefore they may have a high transfer rate to breast milk. This study investigated the lactational transfer of PFCAs with carbon chain lengths of 8 to 13 in mice. Lactating dams were given a single intravenous administration of PFCAs (C8 to C13) during the postnatal period (8&ndash, 13 days after delivery). Milk was collected from the dam 24 h after administration using a milking device built in-house. Plasma was obtained from the dam at the same time as milk collection. The observed milk/plasma (M/P) concentration ratios were 0.32 for C8, 0.30 for C9, 0.17 for C10, 0.21 for C11, 0.32 for C12, and 0.49 for C13. These results indicate that the M/P concentration ratio is not related to the lipophilicity of PFCAs. However, estimated relative daily intake, an indicator of how much PFCA is transferred from dams to pups per body weight, increased with chain length: 4.16 for C8, 8.98 for C9, 9.35 for C10, 9.51 for C11, 10.20 for C12, and 10.49 for C13, which may be related to the lower clearance of long-chain PFCAs. These results indicate the importance of future risk assessment of long-chain PFCAs.
- Published
- 2020
- Full Text
- View/download PDF
48. Alkyl-carbon chain length of two distinct compounds and derivatives are key determinants of their anti-Acanthamoeba activities
- Author
-
Roderick A.M. Williams, Charles McGinness, Theo Martial, Mariana Masala, Ronnie Mooney, and Fiona L. Henriquez
- Subjects
0301 basic medicine ,Parasitic infection ,Cytoplasm ,Phenotypic screening ,Phosphorylcholine ,030106 microbiology ,Antiprotozoal Agents ,lcsh:Medicine ,Article ,Microbiology ,Cell Line ,03 medical and health sciences ,Inhibitory Concentration 50 ,parasitic diseases ,medicine ,lcsh:Science ,Cytotoxicity ,Alkyl ,chemistry.chemical_classification ,Carbon chain ,Acanthamoeba castellanii ,Multidisciplinary ,biology ,Cell Death ,lcsh:R ,DNA ,medicine.disease ,biology.organism_classification ,Carbon ,Acanthamoeba ,Contact lens ,Quaternary Ammonium Compounds ,030104 developmental biology ,chemistry ,Acanthamoeba keratitis ,Cell culture ,lcsh:Q - Abstract
The opportunistic pathogen, Acanthamoeba castellanii is the causative agent for the sight threatening infection Acanthamoeba keratitis (AK). It is commonly associated with contact lens wearers, and prevalence is increasing at an alarming rate due to an inadequate preventive strategy to protect the lens from this protist. This problem is compounded by the lack of an effective acanthamoebocide, particularly with cysticidal activity in the contact lens solutions. We have used cytotoxicity assays and a variety of biophysical approaches to show that two molecules with tails made of alkyl carbon, alkylphosphocholines (APCs) and quaternary ammonium compounds (QACs) had significant chain-length dependent efficacy against A. castellanii trophozoites, the latter producing death via permeabilization, and DNA complexing. QACs were more effective than APCs and had activity against cysts. Conversely, the QAC with 12 alkyl carbon chain, was non toxic, its presence increased A. castellanii trophozoites biomass and delayed encystation by 96 h. Interestingly, it was unable to induce excystation and increased trophozoite sensitivity to APC16. These results present a mono- and multi-inhibitor management strategy effective against trophozoites and cysts that may be useful for formulating into contact lense cleaning solutions and reducing AK incidence.
- Published
- 2020
49. Is the Carbon Nanotube-Catalyst Interface Clean during Growth?
- Author
-
Qiu L and Ding F
- Subjects
- Kinetics, Catalysis, Molecular Dynamics Simulation, Nanotubes, Carbon
- Abstract
Revealing a "true" picture of the carbon nanotube (CNT) growth front at the catalyst surface is critical to understanding the mechanism of CNT growth. If the CNT-catalyst interface is clean or messy, which will greatly affect the mechanism of controlled CNT growth, has never been properly solved either experimentally or theoretically. Here, this issue by ab initial calculation-based kinetic analysis and classical molecular dynamic (MD) simulations is revisited. It is found that the appearance of carbon chains at the CNT-catalyst interfaces or the "messy" interfaces in MD simulations is a consequence of the very short simulation time, and a "clean" CNT-catalyst interface will emerge if the simulation time is close to that in real experiments. This study reveals that, during real CNT experimental growth, a "clean" CNT-catalyst interface with zigzag, armchair, and/or kink sites dominates the growth kinetics, and therefore, the controllable CNT growth by tuning the CNT-catalyst interface is feasible., (© 2022 Wiley-VCH GmbH.)
- Published
- 2022
- Full Text
- View/download PDF
50. Nonionic surfactants and their effects on asymmetric reduction of 2-octanone with Saccharomyces cerevisiae
- Author
-
Yunquan Zheng, Zhijian Huang, Yanghao Guo, Feng Li, Liangbin Li, Jianmin Yang, and Xianai Shi
- Subjects
0301 basic medicine ,2-Octanone ,Alkylphenol ,lcsh:Biotechnology ,Saccharomyces cerevisiae ,Positive reaction ,Biophysics ,Side reaction ,lcsh:QR1-502 ,Applied Microbiology and Biotechnology ,lcsh:Microbiology ,03 medical and health sciences ,lcsh:TP248.13-248.65 ,Moiety ,Organic chemistry ,Carbon chain ,Octanone ,biology ,Chemistry ,Nonionic surfactant ,Asymmetric reduction ,biology.organism_classification ,030104 developmental biology ,Yield (chemistry) ,Original Article - Abstract
In an aqueous buffer system, serious reverse and side reactions were found in the asymmetric reduction of 2-octanone with Saccharomyces cerevisiae. However, some nonionic surfactants added to the aqueous buffer system improved the bioreduction process by decreasing the reverse and side reaction rates in addition to effectively increasing the average positive reaction rate. Further, a shorter carbon chain length of hydrophilic or hydrophobic moieties in surfactants resulted in a higher yield of (S)-2-octanol. The alkylphenol ethoxylate surfactants had a less influence than polyoxyethylenesorbitan trialiphatic surfactants on the product e.e. It suggested that the product e.e. resulting from the change of carbon chain length of the hydrophobic moieties varied markedly compared with the change of carbon chain length of the hydrophilic moiety. Emulsifier OP-10 and Tween 20 markedly enhanced the yield and product e.e. at the concentration of 0.4 mmol L−1 with a yield of 73.3 and 93.2%, and the product e.e. of 99.2 and 99.3%, respectively, at the reaction time of 96 h.
- Published
- 2018
- Full Text
- View/download PDF
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