Search

Carbyne, a linear chain of carbon atoms, is the truly one-dimensional allotrope of carbon and the strongest known Raman scatterer. Here, we use tip-enhanced Raman scattering (TERS) to further enhance the Raman response of a single carbyne chain confined inside a double-walled carbon nanotube. We observe an increase of the anti-Stokes scattering by a factor of 3290 and a 22-fold enhancement of the anti-Stokes/Stokes ratio relative to far-field measurements. The power dependence of the anti-Stokes/Stokes ratio under TERS conditions is indicative of coherent Stokes–anti-Stokes scattering mediated by an excited phonon. The role of resonance effects and laser-induced heating are discussed and potential opportunities are outlined., Nano Letters, 22 (8), ISSN:1530-6984, ISSN:1530-6992

Prodrug-based nanoassembly emerges as a hopeful way for the efficient delivery of antitumor drugs, with carrier-free structure and ultra-high drug loading. Carbon chains are widely used to design self-assembling prodrugs. The impacts of the length of carbon chains on the self-assembly stability, drug delivery efficiency and antitumor effect of prodrugs have not been fully elucidated. Here, three paclitaxel prodrugs were synthesized by conjugating paclitaxel with octanol (C8), decanol (C10) or dodecanol (C12) through disulfide bond. The three prodrugs could form homogeneous nanoparticles, with over 50% drug loading and redox dual-responsivity. Interestingly, the length extension of carbon chains ameliorates the self-assembly and the colloidal stability of prodrugs, thus improving the drug delivery efficiency. The optimal paclitaxel-dodecanol prodrug nanoassemblies exhibit better antitumor efficacy than Taxol and Abraxane. These findings are meaningful for the rational design of advanced nanomedicines in cancer therapy.

A series of probes KJ-x (x = 1−3) with carbon chains of different lengths based on the matrix of rhodamine B were engineered to detect Ag+ in aqueous solution in this work. Among them, KJ-1 is selected as the best option after in vitro investigation in view of its most sensitive and rapid response to Ag+, whose possible sensing mechanism is studied by experimental investigation and theoretical calculation. To identify the practical application of the probe, the detection of Ag+ in nonantibiotic fungicide Silver&Health and differentiation between normal hepatocytes and hepatoma cells using confocal imaging was conducted.

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.

Three new trichostatin analogues, ulleunganilines A-C (1-3), and seven known trichostatins (4-10) were isolated from cultures of Streptomyces sp. 13F051. NMR, UV, and MS data indicated that the planar structures of 1-3 consisted of modified side chains in the trichostatic acid moiety. The absolute configuration of the 2,4-dimethyl-branched carbon chains in 1 and 2 was determined by the PGME method, while the amino acid group in 3 was identified by advanced Marfey's method. Based on the structure of the modified side chains, the origin of 1-3 is proposed. Further experiments indicated that 1 and 3 displayed moderate histone deacetylase inhibitory activity, suggesting that not only the hydroxamate group but also the N,N-dimethyl group were essential for the inhibitory activity.

Ketonization reactions provide a feasible approach to remove oxygen and increase carbon chain length for conversion of biomass derived carboxylic acids. However, the reaction suffers from fast catalyst deactivation and low ketone selectivity. In this work, Lewis acidic heteroatom Ti-, Zr-, Ce-, and Sn-Beta zeolites were prepared using a two-step post-synthesis method and applied in vapor phase ketonization of propionic acid at 350 °C. Among these zeolites, Zr-Beta shows both the highest activity and selectivity. Characterizations indicate that Zr prefers the vacant tetrahedral site when the Zr content is 96% at a space time of 2 h. The amount of coke deposition on Zr-Beta is about 1/3 of that on H-Beta, and the structure of Zr-Beta is preserved after 60 h of reaction. The results of this work indicate that Zr-Beta zeolite is a promising catalyst for ketonization with good stability and high selectivity toward ketone.

For the first time (N = 6291), a study was undertaken to estimate associations between the concentratio ns of red blood cell folate (RBCF) and concentration of six perfluoroalkyl acids (PFAAs), namely, perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorodecanoic acid (PFDA), perfluorononanoic acid (PFNA), and perfluoroundecanoic acid (PFUnDA) for US adults aged ≥20 years by fitting regression models for the data from National Health and Nutrition Examination Survey for 2007-2014. In almost consistent fashion, increasing concentrations of PFAAs were associated with decreasing concentrations of RBCF. For the total population, for a 10% increase in the concentrations of PFOA, PFOS, PFDA, PFHxS, PFNA, and PFUnDA, percent decreases in RBCF concentrations were found to be 0.33%, 0.66%, 0.83%, 0.16%, 0.89%, and 0.43%, respectively. RBCF concentrations of PFAAs were found to be 1104, 1042, 100, and 936 nmol/L across the four quartiles of PFOS; 112, 1068, 1009, and 948 nmol/L across the four quartiles of PFDA; 1125, 1054, 1005, and 967 nmol/L across the four quartiles of PFNA; and 1099, 1094, 989, and 952 nmol/L across the four quartiles of PFUnDA. Perfluorinated carboxylic acids with carbon chain length > 8 decreased concentrations of RBCF to a greater degree than those carbon chain length ≤ 8. Perfluorinated chemicals with a sulfonic group with carbon chain length > 6 decreased concentrations of RBCF to a greater degree than those carbon chain length ≤ 6. The degree to which concentrations of RBCF decrease varied by age, gender, and race/ethnicity. Non-Hispanic blacks as compared to non-Hispanic whites and Hispanics had the lowest decreases in RBCF concentrations. Mechanisms responsible for negative associations between RBCF and PFAA concentrations are not known and will need to be researched further.

As the known allotropes of carbon have expanded, increasing interest has been shown in one-dimensional carbyne. One approach to studying carbyne has been to synthesize linear carbon chains (LCCs) w...

4-Nonylphenol (4-NP) is a para-substituted phenolic compound comprising a straight or branched carbon chain group while branched 4-NP consists of 211 possible structural isomers. NP is recognised as an environmental pollutant and exists ubiquitously in both the environment and in food. 4-NP, especially branched 4-NP, has been shown to have the potential role of endocrine disruptor and xeno-oestrogen. Moreover, different NP isomers also exhibit different oestrogen-like activities. Recently, it was reported that the isomer-specific profile of 4-NP in foodstuffs varies greatly between and within food groups. Hence, risk assessment based on total branched 4-NP cannot reflect dietary risk. This study reviews the analytical methods applicable to conduct an isomer-specific analysis of 4-NP and its occurrence in foodstuffs. Lastly, research gaps are identified for future research.

In an overview, the relationships between activity, property, and chemical structure of the anthracycline derivatives, as topoisomerase II enzyme inhibitors, were studied in pairs. These analogs were investigated in three categories with known half-maximal inhibitory concentration (IC50), known octanol/water partition coefficient (logP), and both IC50 and logP unknown values. The QSAR and QSPR models were developed on analogs of the first and second groups, respectively. LogP was related to calculated pIC50 ((pIC50)calc) surprisingly (R2 = 0.929, Q2LOO = 0.910, RMSE = 0.235, F = 157.511). External verification was performed through comparing calculated logP (logPcalc) with three programs using 77 analogs out of the training and test sets. In application domain of the model, the suggested model had the highest correlation with ClogP method (R = 0.744) and this was better than the correlation between milogP–ClogP (R = 0.724), AlogP–ClogP (R = 0.662), and AlogP–milogP (R = 0.691). Furthermore, in the case of analogs possessing a long carbon chain substitution (nc ≥ 3), estimation methods had a significant error in calculation logP, while our suggested model provides more accurate results. The proposed algorithm can be useful in primary screening among anthracycline derivatives to select potent drug candidates.

ZSM-48 and ZSM-22 zeolites with similar Si/Al ratio were synthesized and modified by alkali treatment. Moreover, n-dodecane hydroisomerization performance of Pt supported ZSM-22 and ZSM-48 were investigated. The catalytic results showed that the activity and the isomers selectivity of n-dodecane hydroisomerization could be improved by alkali treatment. The isomers distributions were distinct for Pt/ZSM-48 and Pt/ZSM-22. Mono-branched isomers near the end of the chains were more prone to be generated on Pt/ZSM-22 catalyst, which suggested “pore-mouth” catalysis model dominating the hydroisomerization catalysis. However, di-branched isomers and mono-branched isomers with methyl near the middle of the carbon chains were favorable to be formed over Pt/ZSM-48 catalyst according to the “key-lock” catalysis model. Moreover, more central-branched isomers were formed at high reaction temperature (> 320 °C) especially for Pt/ HZSM-22.

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.

The Gemini imidazoline surfactants were synthesized from a series of saturated fatty acids. Electrochemical impedance spectroscopy (EIS), polarization curve, and quantum chemistry methods were used to study the corrosion inhibition behavior of Gemini imidazoline surfactants for X70 carbon steel in NaCl solution. Results reveal that such kind of surfactants has an outstanding inhibition effect on carbon steel X70 in NaCl solution and that the restrained efficiency of Gemini imidazoline in an alkaline solution is better than that in a neutral solution. The shorter the carbon chain length, the higher the suppressive efficiency. The higher the concentration of Gemini imidazoline surfactant, the better the inhibition effect.

The adsorption dynamic and thermodynamic characteristics of Na-Montmorillonite (Na-MT) with two different layer charge density for four types of alkyl ammonium with diverse carbon chain length were systematically studied. The result of adsorption dynamics shows that the adsorption process of Na-MT for alkyl ammonium follows the quasi-second-order dynamics equation; with the increase of layer charge density or carbon chain length of alkyl ammonium, the adsorption reaction rate of Na-MT for alkyl ammonium gradually increases; the adsorption reaction rate of Na-MT for alkyl ammonium at a low amount of added modifier is significantly higher than that at a high amount. The result of adsorption thermodynamics indicates that the adsorption process of Na-MT for alkyl ammonium is an exothermic reaction, and the adsorption efficiency of Na-MT for alkyl ammonium decreases with the decrease of layer charge density or carbon chain length of alkyl ammonium. The change in the entropy of adsorption reaction ΔS showes a decreasing trend after the first increase when the amount of added alkyl ammonium increases; at the same amount of added alkyl ammonium, the increase of temperature contributes to the spontaneous adsorption of Na-MT for alkyl ammonium, and the strength of the spontaneous adsorption process is negatively correlated with the carbon chain length and the amount of added alkyl ammonium. The research result of this study provides a theoretical basis for the application of the adsorption of montmorillonite for alkylammonium in industry.

Super-carbon-chain compounds (SCCCs) are marine organic molecules featuring long polyol carbon chains with numerous stereocenters. Polyol–polyene compounds (PPCs) and ladder-frame polyethers (LFPs) are two major families. It is highly challenging to establish the absolute configurations of SCCCs. In this century, few new SCCC families have been reported. Benthol A, an aberrant SCCC, was obtained from a South China Sea benthic dinoflagellate that should belong to a new taxon. Its planar structure and absolute configuration, containing thirty-five carbon stereocenters, were unambiguously established by a combination of extensive NMR spectroscopic investigations, periodate degradation of the 1,2-diol groups, ozonolysis of the carbon–carbon double bonds, J-based configurational analysis, NOE interactions, modified Mosher's MTPA ester method, and DFT-NMR 13C chemical-shift calculations aided by DP4+ statistical analysis. Benthol A displayed potent antimalarial activity against Plasmodium falciparum 3D7 parasites. This new molecule combines extraordinary structural features, particularly eight scattered ether rings on a C72 backbone chain, which places it within a new SCCC family between PPCs and LFPs, herein termed polyol–polyether compounds. This suggestion was strongly supported by principal component analysis. The discovery of benthol A does not only provide new insights into the untapped biosynthetic potential of marine dinoflagellates, but also opens up a new window for skeletal diversity of SCCCs., The discovery of benthol A, a marine natural product featuring thirty-five carbon stereocenters and eight scattered ether rings within a C72 backbone chain, inaugurates a new family of super-carbon-chain compounds.

A series of viscosity sensitive fluorescent probes 1a-e were synthesized by linking coumarin and oxazolopyridinium via dimethylene in this paper. The viscosity test of probes 1a-e indicated that the fluorescence intensity of the probes enhanced significantly with the increase of viscosity of the system (0.89-865 cP), and exhibited a nearly OFF-ON response to viscosity at 648 nm, 650 nm and 650 nm, respectively. In addition, cells still had a high survival rate after co-culturing with probes 1a-e for 12 h (94-98%). Meanwhile, the laser confocal experiment showed that the variation of the carbon chain length in the oxazolopyridinium could affect the subcellular region of the localization of the probes in cells. When the length of the carbon chain in oxazolopyridinium was between n-C7H15 and n-C12H23, probes 1b-d had the ability to target the endoplasmic reticulum in the cells. Moreover, probes 1b-d showed no significant change in fluorescence intensity after 35 min of continuous laser confocal irradiation, indicating that they had excellent anti-photobleaching properties.

Herein, we report a new uranyl–organic polyhedron U4L4 (L = BTPCA) assembled from uranyl and a semirigid tritopic ligand. By adjusting the carbon chain length of organic templates, two complexes can be obtained based on the diverse secondary assembly of U4L4 cages. The mechanism of different arrangements of U4L4 cages induced by organic templates was explored in detail.

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.

Marine microorganisms are known to produce natural products, so called super carbon chain compounds whose molecular weights (MWs) exceed one thousand, such as amphidinol 3 (AM3) and maitotoxin (MTX...

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.

The study of organic aerosol hygroscopic growth and cloud droplet activation is crucial for accurately quantifying their climate and environmental impacts. However, the physical mechanisms behind organic aerosol hygroscopicity variations are not well understood. In this review, we summarized laboratory and field measurements of the organic aerosol hygroscopicity parameter κOA, discussed the physical understanding of why κOA was generally positively correlated with organic aerosol oxidation level, summarized proposed κOA parameterization schemes, and examined possible explanations for the marked differences among these parameterization schemes. Recent findings challenged the general cognition that cloud condensation nuclei (CCN) activity of secondary organic aerosol depended largely on solubility, showing it to be mainly controlled by molecular weight, yet the universality of this finding needs to be further examined. It was found that carbon chain length and functional groups had significant impacts on κOA and additional parameters other than O/C ratio need to be included when parameterizing κOA of multifunctional compounds, which is typically the case for ambient atmospheric aerosols. Additionally, laboratory results of secondary organic aerosol suggest that κOA might be highly RH-dependent under sub-saturated conditions, especially for biogenic secondary organic aerosols. This review summarized laboratory and field measurements of atmospheric organic aerosol hygroscopicity parameter κOA and its parameterization schemes. The results demonstrate that representing κOA with a single oxidation level parameter still bears large uncertainty, and physical mechanisms associated with hygroscopic growth and cloud activation processes of organic aerosol still remain unresolved and need further investigation.

Monohydric alcohols with varying chain lengths and isomeric structures, which had significant effects on improving the magnesite and dolomite flotation, were added separately to replace part of dodecylamine (DDA). The intensified effects of alcohols differ with different chain lengths and isomeric structures. Alcohols can enhance the adsorption of DDA and reduce the adsorption distance of DDA on both surfaces of magnesite and dolomite. And the adsorption energy of the mixed collector decreased with the increasing chain length of alcohol. The isomeric alcohols presented more significant effects on lowering the adsorption energy of the collectors. The co-adsorption of alcohol compressed the hydration layer and dilute the water concentration in the hydration layer. Changes of the hydration layer were greater with adding alcohol with a long carbon chain and isomeric structure. Thus, alcohols with long chain lengths and isomeric structures performed better in improving the flotation of magnesite and dolomite.

This study synthesized water-based polyurethane with acrylate terminal group (WPUA) using the long carbon chain of stearyl acrylate to synthesize hydrophobic poly-stearyl acrylate (PSA). The proposed process could minimize environmental pollution caused by fluorine-containing monomers. As a water-based polyurethane (WPU) end-capping agent, the hydrophobic PSA and the hydrophilic and water vapor permeable WPU are copolymerized to form a WPUA functional resin with simultaneous water vapor permeability (WVP) and water repellency. Here, 2-mercaptoethanol was used to control the molecular weight of PSA to prepare the acrylate end-capping agent. PSA was then employed in WPU to form WPUA, which is characterized by the moisture permeability of WPU and water repellency of acrylic resin simultaneously. During the WPUA process, dimethylacetamide was used as a neutralizer to replace the traditional toxic chemical control drug triethylamine. This study set up the material and chemical structure to replace the toxic chemical-controlled drugs and organofluoride in the traditional preparation of moisture permeable and water repellent materials. The proposed process was proven to reduce the consumption of organic solvent, achieve WPUA copolymer stability, and provided moisture permeable and water repellent functions. In addition, Fourier transform infrared spectroscopy was used to determine the structure of WPUA, while thermogravimetry analysis and differential scanning calorimetry were performed to establish the thermal properties of WPUA. After the WPUA was padded on nylon fabric, its water drop contact angle was observed through a scanning electron microscope. The results showed that the contact angle of nylon fabric increased significantly, water repellency was reached, and WVP rises by 23.75%.

Herein, we report the facile growth of three-dimensional CsPbBr3 perovskite supercrystals (PSCs) self-assembled from individual CsPbBr3 perovskite quantum dots (PQDs). By varying the carbon chain length of a surface-bound ligand molecule, 1-alkynyl acid, different morphologies of PSCs were obtained accompanied by an over 1000-fold photoluminescence improvement compared with that of PQDs. Systematic analyses have shown, for the first time, that under UV irradiation, CsBr, the byproduct formed during PQDs synthesis, could effectively catalyze the homocoupling reaction between two alkynyl groups, which further worked as a driving force to push forward the self-assembly of PQDs.