Trimethylbenzenes (TMB)

Project ID

1676

Category

IRIS

Added on

Aug. 3, 2011, 12:13 a.m.

Search the HERO reference database

Query Builder

Search query
Journal Article

Abstract  BACKGROUND: Conjugated linoleic acids (CLA) in general, and in particular the trans-10,cis-12 (t10,c12-CLA) isomer are potent modulators of milk fat synthesis in dairy cows. Studies in rodents, such as mice, have revealed that t10,c12-CLA is responsible for hepatic lipodystrophy and decreased adipose tissue with subsequent changes in the fatty acid distribution. The present study aimed to investigate the fatty acid distribution of lipids in several body tissues compared to their distribution in milk fat in early lactating cows in response to CLA treatment. Effects in mammary gland are further analyzed at gene expression level.

METHODS: Twenty-five Holstein heifers were fed a diet supplemented with (CLA groups) or without (CON groups) a rumen-protected CLA supplement that provided 6 g/d of c9,t11- and t10,c12-CLA. Five groups of randomly assigned cows were analyzed according to experimental design based on feeding and time of slaughter. Cows in the first group received no CLA supplement and were slaughtered one day postpartum (CON0). Milk samples were taken from the remaining cows in CON and CLA groups until slaughter at 42 (period 1) and 105 (period 2) days in milk (DIM). Immediately after slaughter, tissue samples from liver, retroperitoneal fat, mammary gland and M. longissimus (13th rib) were obtained and analyzed for fatty acid distribution. Relevant genes involved in lipid metabolism of the mammary gland were analyzed using a custom-made microarray platform.

RESULTS: Both supplemented CLA isomers increased significantly in milk fat. Furthermore, preformed fatty acids increased at the expense of de novo-synthesized fatty acids. Total and single trans-octadecenoic acids (e.g., t10-18:1 and t11-18:1) also significantly increased. Fatty acid distribution of the mammary gland showed similar changes to those in milk fat, due mainly to residual milk but without affecting gene expression. Liver fatty acids were not altered except for trans-octadecenoic acids, which were increased. Adipose tissue and M. longissimus were only marginally affected by CLA supplementation.

CONCLUSIONS: Daily supplementation with CLA led to typical alterations usually observed in milk fat depression (reduction of de novo-synthesized fatty acids) but only marginally affected tissue lipids. Gene expression of the mammary gland was not influenced by CLA supplementation.

Journal Article

Abstract  This article examines some of the ethical concerns relevant for the management of amyotrophic lateral sclerosis (ALS). We emphasize the importance for providing a competent assessment of the clinical deficit to correctly identify the disease and to avoid incorrect diagnoses. Conveying the diagnosis to the patient and their family requires empathy and it is important to remain supportive and positive, even in the face of this incurable disease. The essence of care in ALS is to permit the patient to have optimal function for their level of ability. This may require the use of gastrostomy and non-invasive or permanent ventilation. Employment of a multi-disciplinary team will permit optimization of patient care to achieve a good quality of life for as long as possible. The patient should also be informed of the risks associated with unproven therapies and the risks and potential benefits of therapeutic trials. The wishes of patients in regard to gastrostomy, long-term ventilation and end-of life decisions must be considered in an unbiased fashion. Recent advances in the genetics of familial ALS (FALS) have demonstrated some overlap between FALS, sporadic ALS and fronto-temporal lobar dementia (FTLD). The interpretation and dissemination of the results of genetic testing although important can induce confusion, considerable anxiety and guilt in patients and their families and proper counseling is imperative.

Journal Article

Abstract  On the basis of stereo specific information obtained from crystal structures of CDK2, indole and chromene analogues were designed by suitably substituting the pharmacophores on their moiety and docked with target protein for calculating binding affinities. The binding affinities are represented in glide score. (5E)-5-[(1-methyl-1H-indol-3-yl)methylidene]-2,4,6-trioxotetrahydro-2H-pyrimidin-1-ide (I1), (5E)-5-(1H-indol-3-ylmethylidene)-2,4,6-trioxotetrahydro-2H-pyrimidin-1-ide (I2) and 2-amino-4-(4-methyl phenyl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile (C9) were selected for synthesis and biological testing based on vital interactions. (5E)-5-(1H-indol-3-ylmethylidene)-2,4,6-trioxotetrahydro-2H-pyrimidin-1-ide(I2) and 2-amino-4-(4-methyl phenyl)-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile (C9) were proved to be active against MCF-7 and HeLa cell lines.

Journal Article

Abstract  The first regio- and stereocontrolled total synthesis of the bisphenolic, bisquaternary alkaloid (+)-dispegatrine (1) has been accomplished in an overall yield of 8.3% (12 reaction vessels) from 5-methoxy-d-tryptophan ethyl ester (17). A crucial late-stage thallium(III) mediated intermolecular oxidative dehydrodimerization was employed in the formation of the C9-C9' biaryl axis in 1. The complete stereocontrol observed in this key biaryl coupling step is due to the asymmetric induction by the natural sarpagine configuration of the monomer lochnerine (6) and was confirmed by both the Suzuki and the oxidative dehydrodimerization model studies on the tetrahydro β-carboline (35). The axial chirality of the lochnerine dimer (40) and in turn dispegatrine (1) was established by X-ray crystallography and was determined to be P(S). Additionally, the first total synthesis of the monomeric indole alkaloids (+)-spegatrine (2), (+)-10-methoxyvellosimine (5), (+)-lochnerine (6), lochvinerine (7), (+)-sarpagine (8), and (+)-lochneram (11) were also achieved via the common pentacyclic intermediate 16.

DOI
Journal Article

Abstract  In this paper we demonstrate that the choice of an appropriate non-polar modifier which can provide sufficient chemical interactions with the target analytes may lead to the improvement of the selectivity and sensitivity of differential ion mobility spectrometric (DMS) methods. The influence of the aromatic modifier (benzene) on the DMS sensitivity and separation ability was proven using examples of five aromatic compounds (toluene, ethylbenzene, p-xylene, 1,2,4-trimethylbenzene (TMB), and naphthalene). These compounds can provide the pi-pi interaction with the chosen modifier. The influence of the modifier concentration on the compensation voltage, peak area, and peak width was investigated and discussed. The peak capacity for the mixture of toluene, ethylbenzene, p-xylene, TMB, and naphthalene was increased by about four times when the concentration of the benzene in the carrier gas was 0.09%. The strong influence of the proton affinity of analytes on the peak area in the measurements with a modifier was demonstrated. The peak area of the compounds with low proton affinity (toluene, ethylbenzene) significantly decreases with the increase of the aromatic modifier concentration. However, the peak area of the compounds with high proton affinity was significantly increased when benzene was added to the carrier gas. When the concentration of benzene in the carrier gas was 0.4% the peak area of naphthalene was more than tripled and the peak area of TMB was almost doubled. The increase of the peak area in the DMS equipped with a Ni-63-ionization source was explained by the improved ion transport within the DMS filter region. This differs from the DMS equipped with the APPI-source, which demonstrates increased signal intensities in the presence of aromatic dopants due to the increased ionization efficiency of analytes. Despite the higher response of the DMS in the presence of an aromatic modifier, the limits of detection for calibrations without a modifier and with 0.015% of benzene are within the same range (14.2-99.9 and 10.6-89.5 ng L-1, for the calibration without and with the modifier, respectively). This originates mainly from a higher background signal caused by benzene and a benzene dimer.

DOI
Journal Article

Abstract  Phosphate-modified mesoporous silica nanoparticle (PMSN) with large pores over 10 nm is very effective in disrupting biomimetic aggregates of Pluronic F127 PEO PPO PEO block copolymer induced by Mn2+. Mesoporous silica nanoparticies were prepared using cetyltrimethyl ammonium bromide (DAB) and tetramethyl orthosilicate (TMOS) in basic conditions. Mesopores were expanded up to 15 nm using 1,3,5-trimethylbenzene (TMB) as a pore expander and phosphate groups were attached on the surface of mesoporous silica nanoparticles using 3-(trihydroxysilyl)propyl methylphosphonate (THPMP). F127 block copolymers formed aggregates in Mn2+-containing methanol solution and the aggregation process was abruptly reduced by adding small amount of PMSNs, which are attributed to negatively-charged phosphate groups on PMSN surface and high mesoporosity of PMSNs. TEM images clearly showed PMSNs adsorb F127 block copolymers as well as Mn2+. (C) 2013 Elsevier B.V. All rights reserved.

DOI
Journal Article

Abstract  While exploring water soluble rhodamine based fluorescent polymeric systems for biological imaging applications we came across new rhodamine derivatives that possess interesting optical properties. We report the synthesis of three different 2 ',7 '-diphenylated rhodamine derivatives (1-3) with distinct photophysical properties. The three rhodamine derivatives differ by the number of methyl groups present on the nitrogens and their absorption maxima are red-shifted on increased methylation. We observed an unusual inertness of these compounds toward traditional DCC-DMAP esterification conditions, which we attribute to the ease of lactonization in the presence of even minute amounts of the nucleophile/base DMAP (pK(a) = 9.2). Synthesis of acrylate esters was successfully accomplished using MSNT (1-(Mesitylene-2-sulfonyl)-3-nitro-1,2,4-triazole) coupling conditions using a much milder nucleophile/base, for example, N-methyl imidazole (pK(a) = 6.95). (C) 2014 Elsevier Ltd. All rights reserved.

DOI
Journal Article

Abstract  In July 10, 2012 cold neutrons were generated for the first time with the unique pelletized cold neutron moderator CM-202 at the IBR-2M reactor. This new moderator system uses small spherical beads of a solid mixture of aromatic hydrocarbons (benzene derivatives) as the moderating material. Aromatic hydrocarbons are known as the most radiation-resistant hydrogenous substances and have properties to moderate slow neutrons effectively. Since the new moderator was put into routine operation in September 2013, the IBR-2 research reactor of the Frank Laboratory of Neutron Physics has consolidated its position among the world's leading pulsed neutron sources for investigation of matter with neutron scattering methods. (C) 2013 Elsevier B.V. All rights reserved.

DOI
Journal Article

Abstract  This study considers the application of a PDVSA Intevep additive (HIPZD) and a FCC Y zeolite commercial catalyst to reduce sulfur species in gasoline range hydrocarbons. The HIPZD additive and the FCC catalyst are blended and contacted with thiophene or benzothiophene and 1,3,5 trimethylbenzene (TMB) in a CREC Fluidized Riser Simulator. Temperatures, partial pressures, reaction times and C/O (catalyst/oil) ratios selected for the experiments, are representative of FCC industrial units. While it is shown that as expected, the proposed additive is not able to selectively remove benzothiophene species, it is proven that HIPZD displays excellent performance for thiophene removal in gasoline aromatic hydrocarbon media. This selective thiophene adsorption can be managed with minimal thiophene alkylation and gasoline catalytic cracking. It is found in this respect, that thiophene selective adsorption on the HIPZD occurs for reaction times smaller than 7 s. It is also observed that a 10 wt% HIPZD and 90 wt% FCC catalyst blend provides both a good and a practical manner to implement the HIPZD additive in FCC. Thus, on the basis of the results reported, it is anticipated that the HIPZD additive can provide valuable "in situ'' thiophene selective adsorption for the removal of thiophene under typical FCC riser operation conditions. (C) 2014 Elsevier Ltd. All rights reserved.

Journal Article

Abstract  Complement-dependent cytotoxicity (CDC) is a potent promoter of tumor clearance during monoclonal antibody therapy. Complement activation on antibody-bearing tumor cells results in formation of the membrane attack complex (MAC), which activates cell death. The complement activation cascade that bridges between antibody binding and MAC formation is regulated by complement inhibitors that are over-expressed on tumor cells. In order to bypass those complement regulators, we have designed an immunoconjugate composed of a humanized single chain Fv of an anti-Tac (CD25) monoclonal antibody fused at its C terminus either to complement protein C9 (scFv-C9) or to complement C7 (scFv-C7) and tagged with six histidines at the C terminal end. Recombinant scFv-C9 and scFv-C7 were expressed in 293T cells and purified. Both are shown to efficiently bind to CD25-positive tumor cells. In addition, scFv-C9, but not scFv-C7, increases MAC deposition on the cells and enhances complement-mediated cell death of target CD25-positive cells. Thus, scFv-C9 fusion protein is potentially a novel reagent for application in cancer immunotherapy.

Journal Article

Abstract  PURPOSE: Total body irradiation (TBI) has been used for bone marrow transplant for hematologic and immune deficiency conditions. The goal of TBI is to deliver a homogeneous dose to the entire body, with a generally accepted range of dose uniformity being within ± 10% of the prescribed dose. The moving table technique for TBI could make dose uniform in whole body by adjusting couch speed. However, it is difficult to accurately estimate the actual dose by calculation and hence in vivo dosimetry (IVD) is routinely performed. Here, the authors present patterns of patient-specific IVD in 161 TBI patients treated at our institution.

METHODS: Cobalt-60 teletherapy unit (Model C9 Cobalt-60 teletherapy unit, Picker X-ray Corporation) with customized moving bed (SITI Industrial Products, Inc., Fishers, IN) were used for TBI treatment. During treatment, OneDose(TM) (Sicel Technology, NC) Metal Oxide-silicon Semiconductor Field Effect Transistor detectors were placed at patient body surface; both entrance and exit side of the beam at patient head, neck, mediastinum, umbilicus, and knee to estimate midplane dose. When large differences (>10%) between the prescribed and measured dose were observed, dose delivery was corrected for subsequent fractions by the adjustment of couch speed and/or bolus placement. Under IRB exempt status, the authors retrospectively analyzed the treatment records of 161 patients who received TBI treatment between 2006 and 2011.

RESULTS: Across the entire cohort, the median ± SD (range) percent variance between calculated and measured dose for head, neck, mediastinum, umbilicus, and knee was -2.3 ± 10.2% (-66.2 to +35.3), 1.1 ± 11.5% (-62.2 to +40.3), -1.9 ± 9.5% (-66.4 to +46.6), -1.1 ± 7.2% (-35.2 to +42.9), and 3.4 ± 12.2% (-47.9 to +108.5), respectively. More than half of treatments were within ± 10% of the prescribed dose for all anatomical regions. For 80% of treatments (10%-90%), dose at the umbilicus was within ± 10%. However, some large differences greater than 35% were also found at several points. For one case, the knee received double the prescribed dose. When the dose differences for multiple fractions were averaged, compliance (± 1 0%) between the prescription and measured dose was improved compared to the dose difference of the first single fraction, for example, as at umbilicus, which improved from 83.9% to 98.5%.

CONCLUSIONS: Actual dose measurement analysis of TBI patients revealed a potentially wide variance from the calculated dose. Based from their IVD method for TBI using Cobalt-60 irradiator and moving table, ± 10% over entire body is hard to achieve. However, it can be significantly improved with immediate feedback after the first fraction prior to subsequent treatments.

Journal Article

Abstract  A new antibacterial chlorinated benzophenone derivative, (±)-pestalachloride D (1), along with a related analog, (±)-pestalachloride C (2), was recently isolated from the marine-derived fungus Pestalotiopsis sp. isolated from a soft coral Sarcophyton sp. collected from Yongxing Island in the South China Sea. Both chiral HPLC analysis and single-crystal X-ray data indicated that 1 is a racemic mixture. Interestingly, 1 did not exhibit any effect in the zebrafish embryo teratogenicity assay, while 2 led to abnormal growth. The potential impact on zebrafish embryo growth is discussed based on their crystal structures. The main difference of crystal structures between 1 and 2 is that the six-member non-aromatic ring (O4, C10, C9, C8, C2', and C3') in 1 exhibits a distorted chair conformation, while 2 shows a distorted boat conformation. Moreover, compounds 1 and 2 both exhibited moderate antibacterial activity.

Journal Article

Abstract  The objective of this study was to investigate the transfer of supplemented trans-10,cis-12 (t10,c12) and cis-9, trans-11 (c9,t11) conjugated linoleic acids (CLA) into the body of dairy cows during the first 105 days in milk (DIM). Therefore, five out of 25 first lactation German Holstein cows were slaughtered at 1 DIM without previous CLA or fat supplementation. The remaining animals received daily 6.0 g t10,c12 CLA and 5.7 g c9,t11 CLA as feed supplement (Group CLA, 10 cows) or a stearic acid-based control fat supplement (Group CON, 10 cows). From both groups, five cows were slaughtered at 42 and 105 DIM, respectively. During the slaughter process, the empty body mass of the cow was partitioned into nine fractions (retroperitoneal fat, omental fat, mesenteric fat, subcutaneous fat, meat, bone, offal, hide and mammary gland). The fat content and the fatty acid composition of these fractions were determined. The c9,t11 CLA isomer was detected in all fractions across all groups, but the amount of c9,t11 CLA was not changed because of CLA supplementation. Except for the retroperitonealfat depot, no t10,c12 CLA was detected in the fractions of Group CON. After CLA supplementation, the amount of t10,c12 CLA in the retroperitoneal, mesenteric, subcutaneous, offal and mammary gland fractions was increased. The transfer of t10,c12 CLA into the fractions was more pronounced from 42 until 105 DIM. However, the transfer efficiency of consumed t10,c12 CLA into the fat depot fractions and all fractions was <0.1% and <0.2%, respectively. Overall, the transfer of supplemented CLA isomers into the dairy cow's body was only marginal during the first 105 DIM.

Journal Article

Abstract  Herein we discuss the structure elucidation of a labile estradiol-related degradant, X1. X1 was detected at Gedeon Richter as an unknown trace impurity in a pharmaceutical formulation containing estradiol (1a) and norethisterone acetate (NA) as active ingredients. The structural identification of X1 proved to be an unusually complex task involving an initial structural hypothesis based on some limited analytical data (UV) obtained from the formulation, synthetic work targeting the proposed structure, chromatographic enrichment from the synthetic reaction mixture, (HPLC)-MS and MS-MS studies of the formulation and of samples from the synthesis using almost all available ionization modes, preparative LC enrichment, and the complementary use of off-line and on-line NMR techniques. Based on these results, X1 was finally characterized as a new oxidative product of estradiol, containing an epoxy function over the C9-C10 bond. During the structure determination of X1 its secondary and tertiary decomposition products were also identified as a new secoepoxy (6) and a known seco derivative (5a) of estradiol, respectively. On this basis a new oxidative decomposition mechanism of estradiol and its analogues could be proposed. A generalization of the mechanism of this pathway can more readily explain the formation of some oxidative secosteroid degradants than the mechanism proposed earlier in the literature.

Journal Article

Abstract  Repeat expansions in C9orf72 are a major cause of frontotemporal dementia with amyotrophic lateral sclerosis (FTD-ALS). Not all FTD-ALS patients show expansions. The study examined whether there are clinical differences between FTD-ALS patients with and without expansions in C9orf72. We examined case notes from consecutive FTD-ALS patients, screened for C9orf72 expansions, and documented demographic, neurological, behavioural and cognitive characteristics. Sixty patients met the selection criteria, of whom 11 showed expanded repeats (C9-positive) and 49 did not (C9-negative). A strong male bias was present in the C9-negative group only. A family history of FTD or ALS was recorded in both groups, but was significantly more common in C9-positive cases. Psychotic and irrational behaviours, apathy, disinhibition and loss of empathy were significantly more common in C9-positive cases, with a trend towards more frequent bulbar signs. No differences were found in onset age, presentation (ALS or FTD first), or cognitive changes (language and executive impairments). In conclusion, FTD-ALS is not clinically uniform. Phenotypic differences exist between patients with and without C9orf72 expansions, suggesting that FTD-ALS may be underpinned by distinct neurobiological substrates. The presence of psychiatric symptoms in the context of FTD-ALS should alert clinicians to the possibility of C9orf72 expansions.

Journal Article

Abstract  The first step that precedes hematopoietic transplantation is elimination of pathological hematopoiesis by administration of myeloablative doses of radiochemotherapy. This eliminates hematolymphopoietic cells and at the same time damages hematopoietic microenvironment in bone marrow (BM). The damage of BM tissue leads to activation of complement cascade (CC), and bioactive CC cleavage fragments modulate several steps of BM recovery after transplantation of hematopoietic stem progenitor cells (HSPCs). Accordingly, C3 cleavage fragments (soluble C3a/desArgC3a and solid phase iC3b) and generation of soluble form of C5b-C9 also known as membrane attack complex (MAC) as well as release of antimicrobial cationic peptides from stromal cells (cathelicidin or LL-37 and beta-2 defensin) promote homing of HSPCs. To support this, C3 cleavage fragments and antimicrobial cationic peptides increase homing responsiveness of transplanted HSPCs to stroma-derived factor-1 (SDF-1) gradient. Furthermore, damaged BM cells release several other chemoattractants for HSPCs such as bioactive lipids sphingosine-1-phosphate (S1P) and ceramide-1-phosphate (C1P) and chemotactic purines (ATP and UTP). In this chapter, we will discuss the current view on homing of transplanted HSPCs into BM that in addition to SDF-1 is orchestrated by CC, antimicrobial cationic peptides, and several other prohoming factors. We also propose modulation of CC as a novel strategy to optimize/accelerate homing of HSPCs.

Journal Article

Abstract  5-N-acetylneuraminic acid, commonly known as sialic acid (Sia), constitutes a family of N- and O-substituted 9-carbon monosaccharides. Frequent modification of O-acetylations at positions C-7, C-8, or C-9 of Sias generates a family of O-acetylated sialic acid (O-AcSia) and plays crucial roles in many cellular events like cell-cell adhesion, proliferation, migration, etc. Therefore, identification and analysis of O-acetylated sialoglycoproteins (O-AcSGPs) are important. In this chapter, we describe several approaches for successful identification of O-AcSGPs. We broadly divide them into two categories, i.e., invasive and noninvasive methods. Several O-AcSias-binding probes are used for this purpose. Detailed methodologies for step-by-step identification using these probes have been discussed. We have also included a few invasive analytical methods for identification and quantitation of O-AcSias. Several indirect methods are also elaborated for such purpose, in which O-acetyl group from sialic acids is initially removed followed by detection of Sias by several approaches. For molecular identification, we have described methods for affinity purification of O-AcSGPs using an O-AcSias-binding lectin as an affinity matrix followed by sequencing using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF-TOF) mass spectroscopy (MS). In spite of special attention, loss of O-acetyl groups due to its sensitivity towards alkaline pH and high temperature along with migration of labile O-acetyl groups from C7-C8-C9 during sample preparation is difficult to avoid. Therefore there is always a risk for underestimation of O-AcSias.

Journal Article

Abstract  The concentrations of brain white-spirit (8052413) components following subchronic exposure to white-spirit vapor were determined in rats. The effects on brain neurotransmitters were also examined. Male Mol:WIST-rats were exposed to 400 or 800 parts per million (ppm) white-spirit vapor 6 hours daily for 5 days a week for 3 weeks. They were then killed and the brains were removed, weighed, and homogenized. The homogenates were analyzed for white-spirit components by gas chromatography with flame ionization detection. Other brains were assayed for total protein, noradrenaline, dopamine, 5-hydroxytryptamine (5HT), acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE). The concentrations of total white-spirit in the brains of rats exposed to 400 and 800ppm vapor were 3.4 and 10.2 milligrams per kilogram. The concentrations of the aliphatic and aromatic components increased in a dose related manner. The 800ppm exposure significantly increased brain dopamine, noradrenaline, and 5HT concentrations. The 400ppm exposure significantly increased the concentration of noradrenaline. White-spirit did not significantly affect brain weight, total protein concentration, or AChE or BuChE activity. The authors conclude that white-spirit causes significant accumulations of its aromatic and aliphatic components in the brain. The white-spirit induced increases in noradrenaline, dopamine, and 5HT concentration could reflect changes in activity of the corresponding neurons.

DOI
Journal Article

Abstract  Laminar flame speeds of mixtures of air with n-C14H30, n-C16H34, a petroleum-derived JP-5 jet fuel, a camelina-derived hydrotreated renewable JP-5 jet fuel, a petroleum-derived F-76 diesel fuel, and an algae-derived hydrotreated renewable F-76 diesel fuel, were measured in the counterflow configuration at atmospheric pressure and elevated unburned mixture temperatures. Digital particle image velocimetry was used to measure the axial flow velocities along the stagnation streamline. The experiments for n-C14H30/air and n-C16H34/air mixtures were modeled using recently developed kinetic models, and the experimental data were predicted satisfactorily. Both experiments and simulations revealed that the laminar flame speeds of n-C14H30/air and n-C16H34/air mixtures are very close to each other, as expected. On the other hand, the laminar flame speeds for the four practical fuels were found to be lower than n-C14H30 and n-C16H34, due to the presence of aromatics and branched hydrocarbons. Similarly, the laminar flame speeds for the alternative fuels were found to be higher than the petroleum-derived ones, again due to the presence of aromatic compounds in the latter. Further insight into the effects of kinetics and molecular transport was obtained through sensitivity analysis. (C) 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Journal Article

Abstract  Certain coral reef systems north of the Arabian Gulf are characterized by corals with a unique ability to thrive and flourish despite the presence of crude oil continuously seeping from natural cracks in the seabed. Harboring oil-degrading bacteria as a part of the holobiont has been investigated as a potential mechanism of adaptation and survival for corals in such systems. The use of conventional and molecular techniques verified a predominance of bacteria affiliated with Gammaproteobacteria, Actinobacteria and Firmicutes in the mucus and tissues of Acropora clathrata and Porites compressa. These bacteria were capable of degrading a wide range of aliphatic (C9-C28) aromatic hydrocarbons (Phenanthrene, Biphenyl, Naphthalene) and crude oil. In addition, microcosms supplied with coral samples and various concentrations of crude oil shifted their bacterial population toward the more advantageous types of oil degraders as oil concentrations increased.

Journal Article

Abstract  Hypoxia, which leads to dysfunctional cell metabolism, and complement activation both play central roles in the pathogenesis of rheumatoid arthritis (RA). Recent studies have reported that mice deficient for the complement-inhibitory protein CD59 show enhanced susceptibility to antigen-induced arthritis and reported that statins have anti-inflammatory effects in RA. We hypothesized that the anti-inflammatory effect of statins in RA relates in part to their ability to increase CD59 expression in hypoxic conditions and therefore to reduce complement activation. Flow-cytometric analysis showed that CD59 expression on endothelial cells (EC) was unaffected by atorvastatin in normoxia (21% O2), whereas in hypoxic conditions (1% O2) an up to threefold dose-dependent increase in CD59 expression was seen. This effect of hypoxia was confirmed by treatment of EC with chemical mimetics of hypoxia. The upregulation of CD59 protein expression in hypoxia was associated with an increase in steady-state mRNA. L-Mevalonate and geranylgeraniol reversed the response, confirming a role for inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase and geranylgeranylation. Likewise, inhibition by NG-monomethyl-L-arginine and NG-nitro-L-arginine methyl ester confirmed that CD59 upregulation in hypoxia was nitric oxide dependent. The expression of another complement-inhibitory protein, decay-accelerating factor (DAF), is known to be increased by atorvastatin in normoxia; this response was also significantly enhanced under hypoxic conditions. The upregulation of CD59 and DAF by atorvastatin in hypoxia prevented the deposition of C3, C9 and cell lysis that follows exposure of reoxygenated EC to serum. This cytoprotective effect was abrogated by inhibitory anti-CD59 and anti-DAF mAbs. The modulation of EC CD59 and DAF by statins under hypoxic conditions therefore inhibits both early and late complement activation and may contribute to the anti-inflammatory effects of statins in RA.

Journal Article

Abstract  The chemical composition of emissions from the different anthropogenic sources of non-methane hydrocarbons (NMHC) is essential for modeling and source apportionment studies. The speciated profiles of major NMHC sources in Lebanon, including road transport, gasoline vapor, power generation, and solvent use were established. Field sampling have been carried out by canisters in 2012. Around 67 NMHC (C2 to C9) were identified and quantified by using a gas chromatograph equipped with a flame ionization detector. Typical features of the roadway emissions included high percentages of isopentane, butane, toluene, xylenes, ethylene, and ethyne. Gasoline evaporation profiles included high percentage of the C4-C5 saturated hydrocarbons reaching 59%. The main compounds of the power generator emissions are related to combustion. Toluene and C8-C9 aromatics were the most abundant species in emissions from paint applications. Finally, the impact of the use of region-specific source profile is tackled regarding the implication on air quality.

Journal Article

Abstract  Aerosol samples were collected in autumn 2007 on day- and nighttime basis in the northern receptor site of Beijing, China. The samples were analyzed for total carbon (TC) and water-soluble dicarboxylic acids (C2-C12), oxocarboxylic acids (C2-C9), glyoxal and methylglyoxal to better understand the photochemical aging of organic aerosols in the vicinity of Beijing. Concentrations of TC are 50% greater in daytime when winds come from Beijing than in nighttime when winds come from the northern forest areas. Most diacids showed higher concentrations in daytime, suggesting that the organics emitted from the urban Beijing and delivered to the northern vicinity in daytime are subjected to photo-oxidation to result in diacids. However, oxalic acid (C2), which is the most abundant diacid followed by C3 or C4, became on average 30% more abundant in nighttime together with azelaic, ω-oxooctanoic and ω-oxononanoic acids, which are specific oxidation products of biogenic unsaturated fatty acids. Methylglyoxal, an oxidation product of isoprene and a precursor of oxalic acid, also became 29% more abundant in nighttime. Based on a positive correlation between C2 and glyoxylic acid (ωC2) in nighttime when relative humidity significantly enhanced, we propose a nighttime aqueous phase production of C2 via the oxidation of ωC2. We found an increase in the contribution of diacids to TC by 3 folds during consecutive clear days. This study demonstrates that diacids and related compounds are largely produced in the northern vicinity of Beijing via photochemical processing of organic precursors emitted from urban center and forest areas.

Journal Article

Abstract  Two new compounds, (2R,3R,4R)-3',5'-dimethoxy-3,4,7,4'-tetrahydroxy-flavan (1) and 2-(4-hydroxy-3-methoxybenzoyl)-4-methoxy-benzaldehyde (2), together with 35 known phenolic compounds were obtained from the fruits of Amomum tsao-ko. Structures of the new compounds were elucidated on the basis of spectroscopic means, including 2D NMR, a n d high-resolution M S analysis. The isolated compounds were tested in vitro for t heircomplement-inhibitory properties against the classical pathway (CP) and alternative pathway (AP). The results showed that 14 compounds exhibited anti-complementary activities against the CP and AP with CH50 values of 0.42 - 4.43 mM and AP50 values of 0.53 -1.51 mM. Preliminary mechanism studies showed that 1,7-bis(4-hydroxyphenyl)-4(E)-hepten-3-one (8) blocked C1q, C2, C3, C4, C5 and C9 components of the complement system, and hydroquinone (15) acted on C1q, C2, C3, C5 and C9 components.

  • <<
  • 1 of 222
  • >>
Filter Results