Search results for "Chlorobenzene"

Gas chromatographic determination of organochlorine pesticides; contamination of dicofol, fenson, and tetradifon in fish and natural waters of a wet …

1986

Cellular and molecular mechanisms in the induction phase of contact sensitivity.

1995

During the induction phase of contact sensitivity, hapten-specific Th1 cells are primed by epidermal Langerhans cells. These Langerhans cells present hapten on MHC class II molecules and provide costimulatory signals. This presentation discusses the induction of cytokines in Langerhans cells and keratinocytes by haptens and their regulatory effects on contact sensitivity. Haptens were painted on the skin of normal BALB/c mice and epidermal cells were prepared at various times thereafter. Langerhans cell-derived interleukin (IL)-1 beta mRNA was observed as early as 15 min after hapten paining. In keratinocytes, tumor necrosis factor-alpha, IL-1 alpha, IP-10, MIP-2 and IL-10 were found to be …

Properties of the microsomal and cytosolic glutathione transferases involved in hexachloro-1:3-butadiene conjugation

1989

Hexachloro-1,3-butadiene (HCBD) is a substrate for the hepatic microsomal glutathione transferases and is metabolised at higher rates by these enzymes than their cytosolic counterparts. Conjugation reactions catalysed by the microsomal and cytosolic transferases have been studied and characterized using this substrate and 1-chloro-2,4-dinitrobenzene (CDNB). In rat liver microsomes the Km values for HCBD and CDNB were 0.91 and 0.012 mM and in cytosol 0.51 and 0.10 mM respectively. Vmax values for HCBD were 1.39 and 0.35 nmol conjugate formed/min/mg protein for microsomes and cytosol respectively. In microsomal systems HCBD was a potent competitive inhibitor of the metabolism of CDNB with a K…

Prenatal and postnatal exposure to persistent organic pollutants and attention-deficit and hyperactivity disorder: a pooled analysis of seven Europea…

2018

International audience; Background - Attention-deficit/hyperactivity disorder (ADHD) is increasing worldwide for reasons largely unknown and environmental chemicals with neurotoxic properties, such as persistent organic pollutants (POPs), have been proposed to play a role. We investigated the association between prenatal and postnatal exposure to polychlorinated biphenyl-153 (PCB-153), p-p´-dichlorodiphenyldichloroethylene (p-p'-DDE) and hexachlorobenzene (HCB) and ADHD in childhood. Methods - We pooled seven European birth cohort studies encompassing 4437 mother-child pairs from the general population with concentrations of PCB-153, p-p´-DDE and HCB measured in cord blood, maternal blood o…

Porphyrin Antenna-Enriched BODIPY–Thiophene Copolymer for Efficient Solar Cells

2018

International audience; Low bandgap A−π–D copolymer, P(BdP-DEHT), consisting of alternating BOronDIPYrromethene (BODIPY) and thiophene units bridged by ethynyl linkers, and its porphyrin-enriched analogue, P(BdP/Por-DEHT), were prepared, and their optical and electrochemical properties were studied. P(BdP-DEHT) exhibits strong absorption in the 500–800 nm range with an optical bandgap of 1.74 eV. On the basis of cyclic voltammetry, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels are evaluated to be −5.40 and −3.66 eV, respectively. After the anchoring of zinc(II) porphyrin on the BODIPY unit, P(BdP/Por-DEHT) displays broadened absor…

Relaxation of photogenerated carriers in P3HT:PCBM organic blends.

2009

Relaxing in the sunlight. Long time-transient decays of photogenerated carriers in P3HT:PCBM blends for organic solar cells are interpreted in terms of the relaxation of hole carriers in a broad density of states. The after-pulse time-resolved microwave conductivity (TRMC) decays observed in P3HT:PCBM blends display a dependence on time close to t−β, independent of excitation intensity, in the 10 ns–1 μs range. This is explained in terms of the relaxation of carriers in a Gaussian density of states (DOS). The model is based on a demarcation level that moves with time by thermal release and retrapping of initially trapped carriers. The model shows that when the disorder is large the after-pu…

Congested ferrocenyl polyphosphanes bearing electron-donating or electron-withdrawing phosphanyl groups: assessment of metallocene conformation from …

2011

International audience; The synthesis of novel substituted cyclopentadienyl salts that incorporate both a congested branched alkyl group (tert-butyl, (triphenyl)methyl, or tri(4-tert-butyl)phenylmethyl) and a phosphanyl group is reported. The introduction of either electron-withdrawing or electron-donating substituents (furyl, i-propyl, cyclohexyl, tert-butyl) on P atoms was generally achieved in high yield. The modular synthesis of ferrocenyl polyphosphanes from an assembly of these cyclopentadienyl salts was investigated, leading to the formation of new triphosphanes (denoted as 9-12) and diphosphanes (denoted as 14-16). The resulting phosphanes are not sensitive to air or moisture, even …

A DFT study of [3 + 2] cycloaddition reactions of an azomethine imine with N-vinyl pyrrole and N-vinyl tetrahydroindole

2016

The mechanism and selectivities of the [3+2] cycloaddition (32CA) reactions of azomethine imine (AI) 8 with two N-vinyl five-membered heterocycles (NVFH), 9a and 9b, have been theoretically studied using DFT methods at the MPWB1K/6-31G(d) computational level. The possible ortho/meta regio- and endo/exo stereoselective channels were explored and characterised. The low polar character of these 32CA reactions, which is the consequence of the high nucleophilic character of both reagents, as well as the non-effective reactivity of these NVFH as nucleophiles, accounts for the high calculated activation energies, 16.1 (9a) and 16.8 (9b) kcalmol-1 in chlorobenzene. Analysis of the relative electron…

CCDC 684536: Experimental Crystal Structure Determination

2008

Related Article: A.Valkonen, R.Gawinecki, H.Janota, B.Osmialowski, E.Kolehmainen|2008|Acta Crystallogr.,Sect.E:Struct.Rep.Online|64|o737|doi:10.1107/S1600536808007435

1971

The polymerisation of ethylene was carried out in the presence of (C5H5)2TiCl2/(C2H5)2AlCl in benzene (I) and of TiCl4/(C2H5)AlCl2 in chlorobenzene (II). In the initial state of the polymerisation with I oligomers with a narrow molecular weight distribution are formed. According to their IR and NMR spectra they were identified as predominantly saturated linear hydrocarbons. The effect of a substitution of the cyclopentadienyl rings by R = CH3 and C2H5 was studied as well as the influence of aging particularly on the molecular weight distribution. The catalytic system II yields predominantly unsaturated branched oligomers with broad molecular weight distribution. The ligand effect on the str…