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Los materiales compuestos reforzados con fibras de carbono (CFRP), presentan excelentes propiedades mecánicas, debido a sus elevadas propiedades específicas, por esto cada día están siendo implementados por diversos sectores industriales, como el aeroespacial, automotriz, marino, entre otros. Lo que genera un aumento en los residuos de este material, los cuales son eliminados mediante dos métodos no sostenibles, los vertederos y la incineración. Una solución a esta problemática consiste en reciclar estos materiales, sin embargo, luego del reciclaje existe una reducción de las propiedades al usar fibras de carbono recicladas (rCF), como la pérdida de resistencia a la tracción y la poca adherencia entre el material reciclado y la nueva matriz. El objetivo de este trabajo es desarrollar CFRP, incorporando nanorods de ZnO alineados verticalmente sobre rCF, para mejorar la interfase resina-fibra y de esta manera mejorar las propiedades mecánicas del material compuesto. Las rCFs se modificaron superficialmente por oxidación ácida (HNO3), posteriormente se hicieron crecer nanorods de ZnO utilizando el proceso por vía húmeda. Luego, fueron funcionalizadas con APTES (3-aminopropiltrietoxisilano) mediante el proceso de hidrolisis para mejorar la interacción físico/química con la matriz epoxi. Las fibras fueron caracterizadas mediante la microscopía electrónica de barrido (SEM), microscopía electrónica de transmisión (TEM), microscopía de fuerza atómica (AFM), espectroscopia ultravioleta-visible (UV-V), difracción de rayos X (DRX), espectroscopia Raman y espectroscopia infrarroja (FT-IR). Por último, se evaluaron las propiedades mecánicas de todas las fibras mediante una prueba de tracción al compuesto y nanoindentación. En la caracterización estructural Raman, se aprecia que la relación 𝐼𝐷/𝐼𝐺, son de 2.037 para las rCF-P-NRDs ZnO y 2.066 para rCF-M-NRDs ZnO, lo que indica que hay un menor daño morfológico respecto a las rCF de control, afirmando que el crecimiento indujo en la recuperación de las fibras. Por otro lado, según los resultados SEM, se puede hacer crecer nanorods de ZnO alineados verticalmente sobre rCF mediante la reacción por vía húmeda, obteniendo diámetros de 179.642 nm. Por último, los valores obtenidos mediante los ensayos de tracción indicaron que hubo una mejora del 45% (rCF-P-NRDs ZnO) y 56% (rCF-M-NRDs ZnO) respecto a la fibra de carbono virgen. 1. INTRODUCCIÓN. ................................................................................................... 1 2. HIPÓTESIS .............................................................................................................. 4 3. OBJETIVOS ............................................................................................................. 4 3.1. Objetivo General ................................................................................................ 4 3.2. Objetivos Específicos ........................................................................................ 4 4. ESTADO DE ARTE. ................................................................................................ 5 4.1. Fibras de Carbono. ............................................................................................. 5 4.1.1. Precursores para obtener fibras de carbono. ............................................... 6 4.1.2. Demanda mundial de las fibras de carbono. ............................................... 9 4.2. Materiales Compuestos. ................................................................................... 11 4.2.1. Tipos de matrices poliméricas. ................................................................. 11 4.3. Propiedades Mecánicas. ................................................................................... 14 4.3.1. Tracción al Compuesto. ............................................................................ 15 4.3.2. Nanoindentación. ...................................................................................... 15 4.4. Reciclaje de Fibras de Carbono. ...................................................................... 16 4.4.1. Tipos de reciclaje. ..................................................................................... 17 4.4.2. Recuperación de rCF a partir de modificaciones superficiales. ............... 20 5. METODOLOGÍA. .................................................................................................. 27 5.1. Modificación superficial de Fibras de Carbono con HNO3 ............................. 27 5.2. Síntesis de nanopartículas de ZnO. .................................................................. 28 5.3. Crecimiento de Nanorods de ZnO. .................................................................. 30 5.4. Funcionalización amínica de fibras de Carbono con Nanorods de ZnO ......... 32 5.5. Fabricación del material compuesto. ............................................................... 33 5.5.1. Caracterización de material compuesto. ................................................... 33 6. RESULTADOS Y DISCUSIÓN DE RESULTADOS. .......................................... 35 6.1. Modificación superficial con HNO3 ................................................................ 35 6.1.1. Resultados FT-IR. ..................................................................................... 35 6.1.2. Resultados Raman. ................................................................................... 37 6.2. Síntesis de Nanopartículas de ZnO .................................................................. 41 6.2.1. Resultados UV-Visible. ............................................................................ 41 6.2.2. Resultados de Microscopia de fuerza atómica AFM. ............................... 41 6.3. Crecimiento de Nanorods de ZnO alineados verticalmente en fibras de carbono recicladas. ................................................................................................................... 43 6.3.1. Resultados de Microscopia Electrónica de Barrido SEM y Microscopia Electrónica de Trasmisión (TEM). ......................................................................... 43 6.3.2. Resultados de Difracción de Rayos X (DRX). ......................................... 46 6.3.3. Resultados Raman. ................................................................................... 49 6.4. Funcionalización amínica de fibras de carbono recicladas con nanorods de ZnO. 52 6.4.1. Resultados FT-IR. ..................................................................................... 52 6.4.2. Resultados Raman. ................................................................................... 53 6.5. Fabricación del Material Compuesto. .............................................................. 55 6.5.1. Resultados de tracción al compuesto. ....................................................... 55 6.5.2. Resultados de Nanoindentación................................................................ 60 7. CONCLUSIONES .................................................................................................. 63 8. REFERENCIAS BIBLIOGRAFICAS ................................................................... 64 Pregrado Químico(a) Trabajos de Investigación y/o Extensión

Our objective was to determine the influence of a high-fat diet (HFD) on fasting and postprandial skeletal muscle substrate metabolism in endurance-trained (ET) compared with sedentary (SED) humans. SED ( n = 17) and ET ( n = 7) males were control-fed a 10-day moderate-fat diet followed by a 5-day isocaloric HFD (55% fat, 30% carbohydrate). Skeletal muscle biopsies were taken in the fasted condition and 4 h after a high-fat meal (820 kcals; 63% fat and 25% carbohydrate). Palmitate-induced suppression of pyruvate oxidation, an indication of substrate preference, and oxidation of fat and glucose were measured in homogenized skeletal muscle in fasted and fed states. Postprandial responses were calculated as percent changes from fasting to fed states. Postprandial suppression of pyruvate oxidation was maintained after the HFD in ET, but not SED skeletal muscle, suggesting greater adaptability to dietary intake changes in the former. Fasting total fat oxidation increased due to the HFD in ET skeletal muscle ( P = 0.006), which was driven by incomplete fat oxidation ( P = 0.008). Fasting fat oxidation remained unchanged in skeletal muscle of SED individuals. Yet, postprandial fat oxidation was similar between groups. Fasting glucose oxidation was elevated after the HFD in ET ( P = 0.036), but not SED, skeletal muscle. Postprandial glucose oxidation was reduced due to the HFD in SED ( P = 0.002), but not ET, skeletal muscle. These findings provide insight into differing substrate metabolism responses between SED and ET individuals and highlight the role that the prevailing diet may play in modulating fasting and postprandial metabolic responses in skeletal muscle.NEW & NOTEWORTHY The relationship between high dietary fat intake and physical activity level and their combined effect on skeletal muscle substrate metabolism remains unclear. We assessed the influence of the prevailing diet in modulating substrate oxidation in skeletal muscle of endurance-trained compared with sedentary humans during a high-fat challenge meal. Collectively, our findings demonstrate the adaptability of skeletal muscle in endurance-trained individuals to high dietary fat intake.

The present article reviews the current state of the UV-spectroscopy method in the pharmaceutical analysis of phenothiazine derivatives. There are three main areas of applied research using UV VIS spectrophotometry in pharmaceutical analysis: quantitative determination of the concentration of organic substances by their own light absorption; resolving the issues of quality control and standardization of medicinal products using UV VIS spectrophotometry; elaboration and improvement of techniques for processing spectral curves, obtaining from them more complete information about the properties of substances. The peculiarities of determination of pharmaceutical substances in various drugs and the problems associated with the use of the chemical reactions prior to UV VIS spectrophotometric measurements are considered. This review article presents the fundamentals for the beginner and, for the expert, discusses quantitative analysis problems. The review of the UV VIS spectrophotometric methods for determination of the main type of pharmaseuticals, such as phenothiazine derivatives is given. The main attention is focused on the achievements of the last decade. The example of piperidine and piperazine derivatives of phenothiazine shows the advantages of using Oxone and diperoxydicarboxylic acids as derivatization reagents for the production of sulfoxides of the corresponding phenothiazines for selective and highly sensitive quantitative determination of them in some pharmaseuticals by UV VIS spectrophotometry.

In this study, water-soluble emissive carbon dots (CDs) are effectively fabricated with specific optical properties and colors by acid oxidation of muskmelon (Cucumis melo) fruit, which are termed as C. melo CDs (CMCDs). The fluorescence properties of CMCDs were tuned by controlling the experimental conditions that allow them to emit different colors, that is, blue (B-), green (G-), and yellow (Y-) CMCDs, with different emission wavelengths at 432, 515, and 554 nm when excited at 342, 415, and 425 nm, respectively. The fabricated multicolor-emissive CDs were confirmed by various analytical techniques. The sizes of B-, G-, and Y-CMCDs were found to be ∼3.5, ∼4.3, and ∼5.8 nm, respectively. The as-prepared CMCDs display stable emissions with quantum yields of 7.07, 26.9, and 14.3% for the three CMCDs, which could act as a promising probe for the selective detection of Hg2+ ions. Upon the addition of Hg2+ ions, the fluorescence intensity of G-CMCDs at 515 nm was quenched largely than that of B- and Y-CMCDs. The spectroscopic results display that the G-CMCDs acted as a sensor for the detection of Hg2+ ions with a wide linear range from 1.0 to 25 μM (R2 = 0.9855) with a detection limit of 0.33 μM. This method was successfully applied to detect Hg2+ ions in biological and water samples. The fabricated multicolor-emissive CMCDs possess the cell (Cunninghamella elegans, Aspergillus flavus, and Rhizoctonia solani) imaging property, suggesting the biocompatible nature for multicolor imaging of various cells.

We recently reported that feeding mice in their early life a diet containing a lipid structure more similar to human milk (eIMF, Nuturis) results in lower body weights and fat mass gain upon high fat feeding in later life, compared to control (cIMF). To understand the underlying mechanisms, we now explored parameters possibly involved in this long-term effect. Male C57BL/6JOlaHsd mice, fed rodent diets containing eIMF or cIMF from postnatal (PN) day 16-42, were sacrificed at PN42. Hepatic proteins were measured using targeted proteomics. Lipids were assessed by LC-MS/MS (acylcarnitines) and GC-FID (fatty-acyl chain profiles). Early life growth and body composition, cytokines, and parameters of bile acid metabolism were similar between the groups. Hepatic concentrations of multiple proteins involved in β-oxidation (+ 17%) the TCA cycle (+ 15%) and mitochondrial antioxidative proteins (+ 28%) were significantly higher in eIMF versus cIMF-fed mice (p

Graphene quantum dots (GQDs) have generated enormous excitement because of their superiority in chemical inertness, biocompatibility and low toxicity. Due to quantum confinement and edge effects, GQDs have excellent properties, attracting extensive attention from scientists in the fields of chemistry, physics, materials science, biology, and other interdisciplinary sciences. In this review, we aim to present a comprehensive view on the synthesis of GQDs for biological applications. We highlight potential methods like acid oxidation, hydrothermal and solvothermal reactions, microwave-assisted methods, electrochemical oxidation, as well as pyrolysis and carbonization for the successful preparation of GQDs. Meanwhile, four representative types of biomedical application based on GQDs, bioimaging, biosensing, drug delivery, and antimicrobial materials, are introduced and discussed in detail. This work will be very useful for quickly gaining knowledge and experience for synthesizing various GQDs, and developing advanced strategies for creating novel functional GQD-based nanomaterials for further applications in biomedicine, materials science, analytical science, and optical nanodevices.

Various metal-based electrocatalysts from nanocrystals, to clusters and single-atoms, have been well-discovered towards high-efficient power devices and electrocatalytic conversion. To accelerate energy transformation materials discovery, developing high-throughput DFT calculations and machine-learning techniques is of great necessity. This review comprehensively outline the latest progress of theory-guided design of advanced energy transformation materials, especially, we focus on the study of single atoms in various power devices, such as fuel cell (oxygen reduction reaction, ORR; acid oxidation reaction; alcohol oxidation reaction), and other reactions for energy-related electrocatalytic conversion of small molecules, such as H2O2 evolution reactions (2e- ORR), water splitting (H2 evolution reaction/O2 evolution reaction, HER/OER), N2 reduction reaction (NRR), and CO2 reduction reactions (CO2RR). Firstly, the electronic structure, interaction mechanism, and reaction activation path are discussed to provide an overall blueprint in electrocatalysis and batteries mentioned above. Thereafter, the experimental synthesis strategies, structural recognition, and electrocatalytic performance for the advanced energy transformation materials are figured out. Finally, some viewpoints into the current issues and future design concept of the advanced energy transformation materials are provided.

A recently reported solvent spraying technique was used herein for incorporation of multi-walled carbon nanotubes (MWCNTs) on unidirectional carbon fiber/epoxy prepregs. The role of the agglomerates reduction of oxidized MWCNTs on Mode-I interlaminar fracture toughness (GIC) of laminated composites was investigated using double cantilever beam tests. Multiscale laminate composites were fabricated using MWCNTs without and with an acid oxidation, agglomerates reduction (AR) and a sequential treatment based on oxidation and AR. For comparison, specimens without MWCNTs were also prepared and tested. Fourier transform infrared analysis shows evidence of an important amount of oxygenated functional groups on the surface of as-received and oxidized MWCNTs. The results also show Mode-I fracture toughness improvements for all the laminated composites compared to reference samples. A substantial 52% increase in the average GIC initiation was achieved for laminated composites reinforced with oxidized AR-MWCN...

The total antioxidant activity, vitamin C and total phenols were measured from sixteen fruits and four peels. The vitamin C content ranged from 8.33 to 72 mg per cent for fruits and 8.25 to 23.33 mg per cent for fruit peels. Total phenols levels were found between 156.7 to 670.7 mg per cent for fruits and 441.0 to 1042.9 mg per cent for fruit peels. Orange, pupnus, pineapple, lemon, mango, date (red) and grape(red) had high vitamin C content whereas plum, pear, papaya, apple, pineapple, orange, date(red), mango and date (yellow) had high content of phenols on fresh weight basis. The total antioxidant capacity (TAC) expressed as per cent inhibition of lenoleic acid oxidation ranged from a high of 70.88 per cent in pineapple to a low of 8.85 per cent in sapota. In case of fruit peels, it was highest for apple peel (81.47%) and lowest for pupnus peel (16.48%). Other fruits found to have higher TAC (>30%) were plum, date (red), apple, date (yellow), orange, pupnus, banana, pear and mango.

Removal of sulfur and nitrogen compounds from national commercial diesel through adsorption onto activated carbon was studied. Brazilian commercial activated carbon samples (AC) were modified by acid oxidation and, alternatively, were impregnated with palladium chloride. Modified carbon samples showed a significant increase in the quantity of acid sites, particularly those AC submitted to impregnation with palladium. Adsorption capacity of the carbon samples increased proportionally to the increase in the acid groups. Adsorption efficiency of the activated carbon impregnated with palladium chloride was over 85% for nitrogen compounds and over 60% for sulfur compounds. The treatment studied was found to be an efficient option for the removal of sulfur and nitrogen compounds present in commercial diesel, and thus it could be an alternative pretreatment in the conventional hydrotreatment process.

The reagent system Oxone®/NaHCO3 is shown to be very convenient for direct conversion of thiols to sulfonic acids. The simple procedure that involves stirring of thiol, Oxone®/NaHCO3 in CH3CN-H2O (3:2, v/v) mixture at 20±5 °C allows access to a variety of aliphatic as well as electron rich and deficient aromatic sulfonic acids. The oxidation is also shown to occur with KBrO3, albeit over longer durations. The mechanism of thiol-to-sulfonic acid oxidation with Oxone® is proposed to proceed via electron transfer steps, which is supported by the formation of disufide at low conversions.

Treatment of α-hydroxy-substituted methoxyallene derivatives with meta-chloroperbenzoic acid provided acyloxy-substituted 1,2-diketones in moderate yields. A mechanism for the formation of these unexpected products is proposed. The configuration of the enantiopure compound (S)-1-(3-methylquinoxalin-2-yl)-1-(4-nitrobenzoyl­oxy)propan-2-yl 3-chlorobenzoate – determined by X-ray crystal structure analysis – indicates the intermediacy of a carbenium ion during formation of the 1,2-diketones. The functionalized 1,2-diketones are valuable starting materials for a variety of products as demonstrated by the synthesis of quinoxalines, an imidazole derivative, and electron-deficient­ alkenes.

Commercial carbon cloth (CC) is an ideal electrocatalysis material to produce oxygen evolution reaction (OER) due to its high conductive and 3D flexible structure, but the lacked active sites limit its application. For improving its OER performance, the present study proposed an effective method combining plasma and acid treatment to introduce oxygen-containing functional groups and produce more active sites on its surface. Compared to the pristine CC, the plasma and acid treated carbon cloth (PN-CC) delivers a reduced overpotential by 34.6% to achieve current density of 10 mA cm−2. The Tafel slope declines from 97.5 mV dec–1 (pristine CC) to 55.9 mV dec–1 (PN-CC), showing an increased OER kinetic. Additionally, PN-CC electrocatalyst shows outstanding stability after 5000 cycles or 25 000 s. The combination of plasma and acid treatment shows a significant potential in surface modification for electrocatalysts.

Objective Investigation of the reactivity of fractions of bilirubin photoisomers with the vanadic acid oxidation method. Methods Bilirubin photoisomers were prepared by irradiating a bilirubin/human serum albumin solution with blue light emitting diode. Direct bilirubin and bilirubin fractions were measured using the vanadic acid oxidation method and high-performance liquid chromatography in the sample before and after irradiation. Results Direct bilirubin was increased in the solution containing bilirubin photoisomers. ( EE)-/( EZ) -cyclobilirubin-IXα and ( ZE)-/( EZ)-bilirubin-IXα completely disappeared after the addition of vanadic acid. Conclusion Bilirubin photoisomers reacted as direct bilirubin in the vanadic acid oxidation method.

In this work, oxidation assessment of vegetable and marine oils was performed based on their quantitative volatile profile and data analysis by 3-way partial least square chemometrics. Classification models were obtained using broad-spectrum isotopically labelled standards on the analysis of 25 volatile compounds from omega-3 fatty acid (FA) degradation by headspace solid phase microextraction gas chromatography time-of-flight mass spectrometry. Our oxidomic approach was performed on edible oils that differed in their origin (marine or vegetable) and in their omega-3 FA profile. In order to achieve a 3D matrix, every oil was oxidized at 6 different time-points. The obtained models classified edible oils according to their volatile degradation pattern. Oxidation of eicosapentaenoic/docosahexaenoic FA was mainly related to 2-propenal, butanal and 2-ethylfuran while α-linolenic acid oxidation was linked to 1-hydroxy-2-butanone and 5-ethyl-2(5H)-furanone. The present research provides valuable information on the degradation differences of omega-3 oils and proposes specific oxidation markers that could be used to ensure their quality assurance and avoid intentional adulterations.

Background: Ischemic heart disease is the most common cause of death all over the world; its rate is expected to be accelerated in the next decade. Adiponectin is a protein hormone that modulates a number of metabolic processes, including glucose regulation and acid oxidation. Objective: To correlate serum levels of adiponectin and CAD severity assessed by Gensini score. Subjects and methods: Ninety subjects were recruited from catheterization unit (36 subjects with normal coronary arteries and 54 patients with CAD) and they were subdivided into four groups according to the number of affected vessel. Their modified Gensini score was calculated according to the severity of coronary lesions. Blood samples were withdrawn to measure adiponectin levels. Results: Adiponectin levels were lower in patients with CAD than those with normal coronary arteries group by a highly significant statistically value (P

SSCI-VIDE+CDFA+NPR:CPI:MBE; International audience; 1,6-Hexanediol is an emerging building-block chemical, which may be derived from biomass and can produce adipic acid for the synthesis of polymers. A series of supported Pt, Bi-Pt, Au, Pd, Au-Pd, and Au-Pt catalysts were prepared and evaluated in the aerobic oxidation of 1,6-hexanediol to adipic acid in aqueous solution without the addition of a base or an acid. The influences of various molar ratios of the metals in the bimetallic systems and the support (C, ZrO2) were studied. Under the conditions used, bismuth did not promote the catalytic performance of Pt catalysts. On the other hand, formation of an alloy of Au-Pd or Au-Pt made the catalysts very effective. A yield of adipic acid of ca. 96% was achieved at 70 °C under 40 bar of air over the Au-Pt catalyst supported on zirconia with a Au/Pt molar ratio of about 1. Recycling tests revealed the possibility to use the catalyst up to 6 times without significant changes in its catalytic performance.

In this paper, the effects of acid oxidation parameters to the structural and electrochemical behavior of multi-walled carbon nanotubes (MWCNTs) were investigated. The parameters studied were acid concentration, oxidation temperature and oxidation time. The measurement of effects was calculated by how much amount of carboxylic groups (-COOH) introduced and how much structural defects occurred, measured by Fourier Transform Infra-Red Spectroscopy (FTIR) and Raman spectroscopy, respectively. Morphological study was carried out by using SEM. Meanwhile, cyclic voltammetry test (CV) was used in purpose to study the effect of COOH amounts and structural defect to the electrochemical behavior of the COOH-MWCNTs by measuring the oxidation current peaks of DNA immobilization (immobilization current, Iimmo). At the end of this study, we had found that the structural defect of COOH-MWCNTs was directly proportional to the amount of COOH produced. By increasing the acid concentration, oxidation temperature and oxidation time, the amounts of COOH will continuously increase, and so on with the structural defect. Meanwhile, from the cyclic voltammetry test, the results had shown that the immobilization current (Iimmo) was directly proportional to the increasing number of COOH. However, the current will started to reduce once the structural defect had occurred too much.

Aqueous-phase oxidation of cis-pinonic acid (CPA) by hydroxyl radicals (OH) was studied using a relative rate technique under acidic and basic conditions. Liquid chromatography (LC) coupled to the negative electrospray ionization (ESI) quadrupole tandem mass spectrometry (MS/MS) was used to monitor the concentrations of CPA and reference compounds. The measured second order reaction rate coefficients of CPA with OH were: 3.6 ± 0.3 × 109 M–1 s–1 (pH 2) and 3.0 ± 0.3 × 109 M–1 s–1 (pH 10) - combined uncertainties are 2σ. These results indicated that the lifetimes of CPA in the atmosphere are most likely independent from the aqueous-phase pH. LC-ESI/MS/MS was also used to tentatively identify the CPA oxidation products. Formation of carboxylic acids with molecular weight (MW) 216 Da (most likely C10H16O5) and MW 214 Da (C10H14O5) was confirmed with LC-ESI/MS/MS. When the initial CPA concentration was increased from 0.3 to 10 mM, formation of additional products was observed with MW 188, 200, 204, and 232 Da....

The recovery of molybdenum from Ni-Mo alloy was investigated by acid oxidation leaching in H2SO4-NaClO3 system and then ion exchange process of leach liquor. The results in the leaching tests show that the leaching rates of nickel, molybdenum and iron are 99%, 97% and 98% respectively under the optimum conditions of H2SO4 dosage of 0.24mol per 20g Ni-Mo alloy, mass ratio of NaClO3/Ni-Mo alloy of 1.0, liquid-solid ratio of 4:1, leaching temperature of 100oC and time of 4h. The extraction of molybdenum in leach liquor was studied by ion exchange. The test results of resins selection show that the D308 resin is the best among resins on molybdenum adsorption. The results from the column tests of the D308 resin indicate that the mass ratio of Ni/Mo in effluent reaches to 10.84 from initial ratio of 0.607 and the adsorption rate of molybdenum is 94.4%.

Calcium/calmodulin dependent protein kinase (CaMK) activation induces mitochondrial biogenesis in response to increasing cytosolic calcium concentrations. Calcium leak from the ryanodine receptor is regulated by reactive oxygen species (ROS), which are increased with high-fat feeding. Therefore, we examined whether ROS-induced CaMKII-mediated signalling induced skeletal muscle mitochondrial biogenesis in selected models of lipid oversupply. In obese Zucker rats and in high fat-fed rodents, in which muscle mitochondrial content was upregulated, CaMKII phosphorylation was increased independent of changes in calcium uptake, as sarco(endo)plasmic (SR) reticulum Ca2+-ATPase (SERCA) protein expression or activity were not altered, implicating altered SR calcium leak in the activation of CaMKII. In support of this, we found that high-fat feeding increased mitochondrial ROS emission and S-nitrosylation of the ryanodine receptor while hydrogen peroxide induced SR calcium leak from the ryanodine receptor and activation of CaMKII. Moreover, administration of a mitochondrial-specific antioxidant (SkQ) prevented high-fat diet-induced phosphorylation of CaMKII as well as the induction of mitochondrial biogenesis. Altogether these data suggest that increased mitochondrial ROS emission is required for the induction of SR-calcium leak, activation of CaMKII and the induction of mitochondrial biogenesis in response to excess lipid availability.

A new approach of oxidation of carbon nanotubes has been used to oxidize the CNTs. A comparative aspect of the mechanical oxidation and acid oxidation process has been established. FTIR analysis and titration method have shown the higher feasibility of the mechanical oxidation method to oxidize the CNTs. Comparatively less damage to the CNTs has been observed in case of mechanically oxidized as compared to acid oxidized CNTs. The mechanical properties of the nanocomposites reinforced with the acid oxidized CNT (ACNT) and mechanically oxidized CNTs (McCNT) were analyzed and relatively higher properties in the nanocomposites reinforced with McCNT were noticed. The less degree of entanglement in the McCNTs was noticed as compared to ACNTs. The dynamic mechanical analysis of the nanocomposites revealed much improved load transfer capability in the McCNT reinforced composites. Further, the rheological properties of the nanocomposites revealed the higher performance of McCNT reinforced composites.

* Present address: MED, Shri G S Institute of Technology & Science, 23, Park Road, Indore, Madhya Pradesh 452003, India. Surface treatment of carbon fibers (CFs) is an excellent way to enhance the fiber–matrix adhesion. However, this is generally at a cost of deterioration in the strength of a fiber. The two effects in opposite directions control the net strength of a composite. The weightage of each factor depends on the selected method and dose. Authors have recently reported on three fiber-treatment techniques (using various doses) such as that with nano-YbF3 (new method); cold remote nitrogen–oxygen plasma (newer one) and γ rays apart from one traditional method of acid oxidation of a fiber. In the present paper, comparative aspects (benefits and limitations) of all these four methods are discussed to enable a right selection of a surface treatment technique of CF to design the composite with a right combination of strength and wear resistance in abrasive wear mode. The composites with these surface treated fabrics and polyetherimide matrix were developed and evaluated for various properties including abrasive wear performance. Specific wear rate of HNO3 treated composite was lowest among these composites while plasma treated composites showed least improvement. Scanning electron microscope (SEM) analysis of worn surfaces showed mechanisms responsible for improved performance of treated composites and high wear rate of untreated composites.

Carbon nanotubes (CNTs) are promising to be the next generation of viable tools for bioapplications. Further advances in such bioapplications may depend on improved understanding of CNTs physical and chemical properties as well as control over their biocompatibility. Herein we performed a systematic study to show how acid oxidation treatment changes CNTs physical and chemical properties and leads to improved CNTs biocompatibility. Specifically, by incubating CNTs in a strong acid mixture we created a user-defined library of CNTs samples with different characteristics as recorded using Raman energy dispersive X-ray spectroscopy, atomic force microscopy, or solubility tests. Systematically characterized CNTs were subsequently tested for their biocompatibility in relation to human epithelial cells or enzymes. Such selected examples are building pertinent relationships between CNTs biocompatibility and their intrinsic properties by showing that acid oxidation treatment lowers CNTs toxicity providing feasible platforms to be used for biomedical applications or the next generation of biosensors.

Although insulin-like growth factor 2 (IGF2) has been reported to be overexpressed in steatosis and steatohepatitis, a causal role of IGF2 in steatosis development remains elusive. Aim of our study was to decipher the role of IGF2 in steatosis development. Hydrodynamic gene delivery of an Igf2 plasmid used for transient Igf2 overexpression employing codon-optimized plasmid DNA resulted in a strong induction of hepatic Igf2 expression. The exogenously delivered Igf2 had no influence on endogenous Igf2 expression. The downstream kinase AKT was activated in Igf2 animals. Decreased ALT levels mirrored the cytoprotective effect of IGF2. Serum cholesterol was increased and sulfo-phospho-vanillin colorimetric assay confirmed lipid accumulation in Igf2-livers while no signs of inflammation were observed. Interestingly, hepatic cholesterol and phospholipids, determined by thin layer chromatography, and free cholesterol by filipin staining, were specifically increased. Lipid droplet (LD) size was not changed, but their number was significantly elevated. Furthermore, free cholesterol, which can be stored in LDs and has been reported to be critical for steatosis progression, was elevated in Igf2 overexpressing mice. Accordingly, Hmgcr/HmgCoAR was upregulated. To have a closer look at de novo lipid synthesis we investigated expression of the lipogenic transcription factor SREBF1 and its target genes. SREBF1 was induced and also SREBF1 target genes were slightly upregulated. Interestingly, the expression of Cpt1a, which is responsible for mitochondrial fatty acid oxidation, was induced. Hepatic IGF2 expression induces a fatty liver, characterized by increased cholesterol and phospholipids leading to accumulation of LDs. We therefore suggest a causal role for IGF2 in hepatic lipid accumulation.

Wet acid oxidation treatment methods have been widely reported as an effective method to purify and oxidize the surface of industrial multi-walled carbon nanotubes. This work examines the use of a concentrated HNO3/H2SO4 mixture in an attempt to optimize the purification procedure of industrial multi-walled carbon nanotubes with diameter distribution statistics. It is shown that acid treatments of several hours are enough to purify the nanotubes. The electrical and thermal conductivities of epoxy composites containing 0.05–0.25 wt% of an acid-treated multi-walled carbon nanotube have been studied. The electrical conductivity of the composites decreases by more than three orders, whereas the thermal conductivity of the same specimen increases very modestly as a function of the filler content.

It is known that the high purity of carbon nanotubes (CNTs) are hard to obtain because of the impurities, which directly affect their unique properties and potential applications. Some modern purification methods including physical separation methods and chemical oxidation methods have been developed for getting the CNTs. But either way, each method still has some deficiencies, such as structure damaged, complex steps and low yield. Now there is a comprehensive multi-step method to overcome this predicament, it combines the air oxidation, hydrochloric acid treatment, SDS dispersion, centrifugation process, mixed acid oxidation and H2O2 oxidation. In this paper, the whole procedures of comprehensive methods are discussed in detail.

This paper presents the results of mass spectrometric investigations of the OH-initiated oxidative aging of α-pinene SOA under simulated tropospheric conditions at the large aerosol chamber facility AIDA, Karlsruhe Institute of Technology. In particular, the OH-initiated oxidation of pure pinic and pinonic acid, two well-known oxidation products of α-pinene, was investigated. Two complementary analytical techniques were used, on-line atmospheric pressure chemical ionization/mass spectrometry (APCI/MS) and filter sampling followed by liquid chromatography/mass spectrometry (LC/ESI-MS). The results show that 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a very low volatile α-pinene SOA product and a tracer compound for terpene SOA, is formed from the oxidation of pinonic acid and that this oxidation takes place in the gas phase. This finding is confirmed by temperature-dependent aging experiments on whole SOA formed from α-pinene, in which the yield of MBTCA scales with the pinonic acid fraction in the gas phase. Based on the results, several feasible gas-phase radical mechanisms are discussed to explain the formation of MBTCA from OH-initiated pinonic acid oxidation.

Insulin resistance is perceived as deleterious, associated with conditions as the metabolic syndrome, type 2 diabetes mellitus and critical illness. However, insulin resistance is evolutionarily well preserved and its persistence suggests that it benefits survival. Insulin resistance is important in various states such as starvation, immune activation, growth and cancer, to spare glucose for different biosynthetic purposes such as the production of NADPH, nucleotides in the pentose phosphate pathway and oxaloacetate for anaplerosis. In these conditions, total glucose oxidation by the tricarboxylic acid cycle is actually low and energy demands are largely met by fatty acid and ketone body oxidation. This beneficial role of insulin resistance has consequences for treatment and research. Insulin resistance should be investigated at the cellular, tissue and whole organism level. The metabolic pathways discussed here, should be integrated in the accepted and valid mechanistic events of insulin resistance before interfering with them to promote insulin sensitivity at any cost. (C) 2012 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved

Two types of the cementitious binders (MWNT/CB, AMNT/CB) filled with 0.5 wt.% multi-wall carbon nanotube (MWNT), and acid-treatment MWNT (AMNT) were prepared. The surfaces of MWNT and AMNT were firstly characterized with TEM micrograph and FT-IR spectrum before and after acid oxidation. The electrical resistivities (ρ) and the longitudinal strains (εl) of two cured nanocomposites under cyclic compressive stress (σ) are real-time collected, in order to investigate their piezoresistivity properties, associated with mechanical behaviors. On one hand, acid treatment can enhance interface bonding between AMNT and cementitious binder decorated with some hydrophilic groups, resulting in some mechanical improvements; on the other hand, it causes better distribution and more network pathway, AMNT/CB has resultantly balanced piezoresistivity property with regular and consistent variation ofρfollowing the σ, or theεl, and fixed stress/strain sensitivity (around 62), compared to that of MWNT/CB.

In this paper, azo dye Acid Red B (ARB) simulation of wastewater was treated with persulfuric acid. By conducting the comparative experiments of the catalysts and analyzing their catalytic mechanisms, the promotion effect of catalysts on the reaction was ranked as: AgNO3>Ag2SO4>CoCl2>CoSO4>FeSO4>FeCl2; in addition, optimum reaction conditions were attained: ARB concentration of 200mg/L, the reaction time 1h, temperature 25°C, oxidant dosage 15mL/L and 6.5×10-5mol/L with catalyst of AgNO3, under which the decolorization rate of ARB was up to 100%, and COD removal rate was up to 72%.

Acidic oxidation methods have been widely reported as an effective method to purify and functionalize the surface of carbon nanotubes (CNTs). Although effective, the strong acids typically employed and the high sonication power used to disperse the nanotubes in the solution frequently cause nanotube damage, limiting their great potential as mechanical and electrical reinforcements. This work examines the use of HNO3, H2SO4 and H2O2 at relatively low concentrations, short treatment times and low sonication power, in an attempt to achieve experimental conditions which efficiently functionalize the surface of multiwalled CNTs minimizing nanotube damage. A low power sonochemical treatment employing 3.0 M HNO3 for 2 h followed by 2 h of identical treatment with H2O2 proved to be the most effective for this aim.

AimInhibition of the acetyl-CoA carboxylase (ACC) system, consisting of the isozymes ACC1 and ACC2, may be beneficial for treatment of insulin resistance and/or obesity by interfering with de novo lipogenesis and beta-oxidation. We have evaluated effects of pharmacological inhibition of ACC by soraphen (SP) on high fat (HF) diet-induced insulin resistance in mice.MethodMale C57Bl6/J mice were fed control chow, a HF diet or a HF diet supplemented with SP (50 or 100 mg/kg/day).ResultsBody weight gain and total body fat content of SP-treated animals were significantly reduced compared with HF-fed mice. Fractional synthesis of palmitate was significantly reduced in mice treated with SP, indicative for ACC1 inhibition. Plasma beta-hydroxybutyrate levels were significantly elevated by SP, reflecting simultaneous inhibition of ACC2 activity. Mice treated with SP showed improved peripheral insulin sensitivity, as assessed by hyperinsulinaemic euglycaemic clamps.ConclusionPharmacological inhibition of the ACC system is of potential use for treatment of key components of the metabolic syndrome.