4-丙基-4''''-氰基联苯的合成研究

以联苯为原料,经Friedel-Crafts反应、还原反应、碘代反应、氰化反应,合成4-丙基-4'-氰基联苯.此方法合成步骤少,操作简单,提纯方便,节省了费用.     

HOXD4 and regulation of the group 4 paralog genes

From an evolutionary perspective, it is important to understand the degree of conservation of cis-regulatory mechanisms between paralogous Hox genes. In this study, we have used transgenic analysis of the human HOXD4 locus to identify one neural and two mesodermal 3' enhancers that are capable of mediating the proper anterior limits of expression in the hindbrain and paraxial mesoderm (somites), respectively. In addition to directing expression in the central nervous system (CNS) up to the correct rhombomere 6/7 boundary in the hindbrain, the neural enhancer also mediates a three rhombomere anterior shift from this boundary in response to retinoic acid (RA), mimicking the endogenous Hoxd4 response. We have extended the transgenic analysis to Hoxa4 identifying mesodermal, neural and retinoid responsive components in the 3' flanking region of that gene, which reflect aspects of endogenous Hoxa4 expression. Comparative analysis of the retinoid responses of Hoxd4, Hoxa4 and Hoxb4 reveals that, while they can be rapidly induced by RA, there is a window of competence for this response, which is different to that of more 3' Hox genes. Mesodermal regulation involves multiple regions with overlapping or related activity and is complex, but with respect to neural regulation and response to RA, Hoxb4 and Hoxd4 appear to be more closely related to each other than Hoxa4. These results illustrate that much of the general positioning of 5' and 3' flanking regulatory regions has been conserved between three of the group 4 paralogs during vertebrate evolution, which most likely reflects the original positioning of regulatory regions in the ancestral Hox complex.     

Fourier Transform Infrared Emission Spectroscopy of the C4Delta-X4Phi, G4Phi-X4Phi, and G4Phi-C4Delta Systems of TiCl

The emission spectrum of TiCl has been investigated in the 3000-12 000 cm-1 region at high resolution using a Fourier transform spectrometer. The bands were excited in a microwave discharge through a flowing mixture of TiCl4 and helium. The observed bands have been classified into three electronic transitions, C4Delta-X4Phi, G4Phi-X4Phi, and G4Phi-C4Delta. In the 3000-3500 cm-1 region, four bands with R heads at 3368.7, 3331.8, 3291.9, and 3243.4 cm-1 have been assigned as the 0-0 bands of the 1/2-3/2, 3/2-5/2, 5/2-7/2, and 7/2-9/2 subbands, respectively, of the C4Delta-X4Phi transition. To higher wavenumbers, four transitions with 0-0 R heads at 10 930.7, 10 921.3, 10 906.5, and 10 886.9 cm-1 have been assigned as the 3/2-3/2, 5/2-5/2, 7/2-7/2, and 9/2-9/2 subbands, respectively, of the G4Phi-X4Phi system of TiCl. Four additional bands with 0-0 R heads at 7568.8, 7596.4, 7622.2, and 7651.7 cm-1 have been identified as the 1/2-3/2, 3/2-5/2, 5/2-7/2, and 7/2-9/2 subbands of the G4Phi-C4Delta transition, respectively. A rotational analysis of a number of vibrational bands of these transitions has been obtained and molecular constants have been extracted. The lowest 4Phi state has been assigned as the ground state of TiCl, by analogy with our recent work on TiF (R. S. Ram and P. F. Bernath, J. Mol. Spectrosc., in press). The correspondence between the electronic states of TiCl, TiF, TiH, and Ti+ is also discussed. Copyright 1997 Academic Press. Copyright 1997Academic Press     

Determination of the diffusion coefficients of CuSO4, ZnSO4, and NiSO4 in aqueous solution

The diffusion coefficients of CuSO₄, ZnSO₄, and NiSO₄ in the aqueous solution systems of MSO₄ and MSO₄-H₂SO₄ were measured at 298 K using a diaphragm-cell method, and are listed as a function of molar concentrations of MSO₄ and H₂SO₄. It was found that the concentration dependencies of the diffusion coefficients for CuSO₄, ZnSO₄, and NiSO₄ in each single metal sulfate solution are very similar. The presence of H₂SO₄ generally causes a less significant concentration dependency of the diffusion coefficients of MSO₄. The concentration dependencies of the diffusion coefficients of CuSO₄ in aqueous solutions of CuSO₄ and CuSO₄-H₂SO₄ are attributed to the changes in the mean activity coefficient of CuSO₄ and the viscosity of the solutions. formerly Graduate Student, Department of Metallurgy, Kyoto University, Kyoto, Japan     

Partial phase diagrams of the ternary systems NaCl-KCl-ZrCl4 and NaCl-KCl-HfCl4

Abstract

Fluoride emissions especially hydrogen fluoride from the aluminium smelting process present the potential for significant environmental damage and the care is, therefore, taken to remove them from the gas stream that leaves the plant. While previous work has focused on improving the scrubbing efficiency, more recent research has investigated the generation of fluoride emissions during the reduction process, in part to understand seasonal changes in fluoride emissions (summer syndrome). Several models have been developed to estimate the amount of hydrogen fluoride generated, but these do not consider the individual sources of fluoride generation and cannot be easily used to assess the impact of changes in relative humidity. This paper presents a new model, still under development, which simulates the hydrolysis of pot gas from an open feeder hole. During the course of this research, it has become clear that the major sources of moisture for hydrogen fluoride generation appear to be alumina, in the form of structural hydroxides and the ambient humidity. It is thought that summer syndrome can be explained by the changes in the ambient humidity. Initial results suggest that, in an open feeder hole, a 3000–5000 ppm hydrogen fluoride (HF) background in pot gas presents, the ambient moisture could account for 30–55% maximum of total HF emission, varying with ambient humidity, CO flaming and bath chemistry. However, the anode hydrogen and adsorbed alumina moisture only have limited contribution to the gaseous fluoride.     

Metabolism of 4-methylaminorex ("EU4EA") in the rat

Metabolism studies were conducted on 4-methylaminorex (4,5-dihydro-4-methyl-5-phenyl-2-oxazolamine [4-MAX]), a potent central nervous system stimulant that has emerged as a drug of abuse under the name "EU4EA", "EU4Euh", and "Ice". Tritiated norephedrine was cyclized with cyanogen bromide to form 3H-4-MAX, which was administered to rats at a dose of 10 mg/kg orally and intravenously. Radioactivity was excreted almost entirely in urine (40% of the dose was excreted by 24 h), primarily as the parent drug (60% of the total excretions were as the parent compound). Three metabolites were identified by high-performance liquid chromatography-tandem mass spectrometry with thermospray ionization: norephedrine, 5-phenyl-4-methyl-2-oxazolidinone, and 2-amino-5-(p-hydroxyphenyl)-4-methyl-2-oxazoline. Stability studies showed that 4-MAX in aqueous solution degraded very slightly to norephedrine upon standing. There was no evidence for glucuronide or sulfate conjugation. These results suggest that the metabolic fate of 4-MAX is similar to that of the amphetamines in that it is eliminated primarily unchanged but undergoes some slight oxidative deamination and aromatic hydroxylation. Hydrolytic degradation back to the synthetic precursor can also occur. There was no evidence for the hydrolysis of the oxazolamine ring to form a urea that has been reported for the demethylated congener aminorex. This suggests that 4-methyl substitution of the oxazoline ring may inhibit metabolism similar to the alpha-methyl substitution of beta-phenylethylamines.     

Moving GLUT4: the biogenesis and trafficking of GLUT4 storage vesicles

The GLUT4 system in muscle and fat cells plays an important role in whole-body glucose homeostasis. Insulin stimulates the translocation of GLUT4 from an intracellular storage compartment to the cell surface. The nature of this compartment remains largely unknown. We review recent studies describing the biogenesis and molecular constituents of the GLUT4 storage compartment and conclude that it is segregated from the endosomal and biosynthetic pathways. Further, we present evidence to suggest that the GLUT4 storage compartment moves directly to the plasma membrane in response to insulin and, hence, is analogous to small synaptic vesicles in neurons. We propose that the GLUT4 storage compartment be referred to as GLUT4 storage vesicles or GSVs.     

Inhibition of mucociliary clearance of the eustachian tube by leukotrienes C4 and D4

The effect of leukotrienes C4 (LTC4) and D4 (LTD4) and prostaglandin E2 (PGE2) on mucociliary clearance of the eustachian tube was investigated in vitro and in vivo. Normal ciliated epithelium was obtained from the eustachian tube of guinea pigs and incubated separately with LTC4, LTD4, and PGE2 at concentrations of 10(-8) mol/L and 10(-6) mol/L. Ciliary activity was measured photoelectrically. Leukotriene D4 progressively inhibited ciliary activity, while PGE2 promoted it. Leukotriene C4 also induced ciliary inhibition. One milliliter each of 10(-5) mol/L LTC4, LTD4, and PGE2 was directly injected into the tympanic bullae of chinchillas under anesthesia. The middle ears were examined by otomicroscopy, tympanometry, and auditory brain stem response over time. Clearance of middle ear effusion was delayed by LTC4 and LTD4, as compared with PGE2 and the control. These findings indicate that LTC4 and LTD4 inhibit mucociliary clearance of the eustachian tube.     

Thermoanalysis of the combined Fe3O4-reduction and CH4-reforming processes

The chemical equilibrium composition of the system Fe₃O₄ + 4CH₄, at 1300 K and 1 atm consists of solid Fe and a 2:1 gas mixture of H₂ and CO. Thermogravimetric (TG) analysis combined with gas Chromatographic measurements was conducted on the reduction of Fe₃O₄ (powder, 2-μm mean particle size) with 2.3, 5, 10, and 20 pct CH₄ in Ar, at 1273, 1373, 1473, and 1573 K. The reduction proceeded in two stages, from Fe₃O_{4 to FeO, and finally to Fe. CR}, conversion and H₂ yield increased with temperature, while the overall reaction rate increased with temperature and CH4 concentration. C (gr) deposition, due to the cracking of CR,, was observed. By applying a topochemical model for spherical particles of unchanging size, the reaction mechanism was found to be mostly controlled by gas boundary layer diffusion. The apparent activation energy reached a maximum at 30 pct reduction extent and decreased monotonically until completion. When compared with the results using instead either H₂ or CO as reducing gas, the reduction achieved completion faster using CH₄, at temperatures above 1373 K.     

The cytoplasmic domain of CD4 promotes the development of CD4 lineage T cells

Thymocytes must bind major histocompatibility complex (MHC) proteins on thymic epithelial cells in order to mature into either CD8+ cytotoxic T cells or CD4+ helper T cells. Thymic precursors express both CD8 and CD4, and it has been suggested that the intracellular signals generated by CD8 or CD4 binding to class I or II MHC, respectively, might influence the fate of uncommitted cells. Here we test the notion that intracellular signaling by CD4 directs the development of thymocytes to a CD4 lineage. A hybrid protein consisting of the CD8 extracellular and transmembrane domains and the cytoplasmic domain of CD4 (CD884) should bind class I MHC but deliver a CD4 intracellular signal. We find that expression of a hybrid CD884 protein in thymocytes of transgenic mice leads to the development of large numbers of class I MHC-specific, CD4 lineage T cells. We discuss these results in terms of current models for CD4 and CD8 lineage commitment.