Enantioselective synthesis and pharmacology of 11-hydroxy-(1'S,2'R)-dimethylheptyl-delta 8-THC

An enantioselective synthesis of the (1'S,2'R)-dimethylheptyl cannabinoid side chain has been developed and employed in the synthesis of 11-hydroxy-(1'S,2'R)-dimethylheptyl-delta 8-THC (3). Pharmacology, in vivo and in vitro, indicate (3) to be one of the most potent traditional cannabinoids known.     

Love as sensory stimulation: physiological consequences of its deprivation and expression

For the present purpose, love is defined as one's having stimulation that one desires. The nature of the stimulation can range on a continuum from the most abstract cognitive, to the most direct sensory, forms. Thus, this definition of love encompasses having an emotional bond with a person for whom one yearns, as well as having sensory stimulation that one desires. We address some of the physiological and perceptual consequences both of having, and of not having, love. We propose a neural mechanism by which deprivation of love may generate endogenous, compensatory sensory stimulation that manifests itself as psychosomatic illness. In addition, we propose a neuroendocrine mechanism underlying sexual response and orgasm. The latter includes vaginocervical sensory pathways to the brain that can produce analgesia, release oxytocin, and/or bypass the spinal cord via the vagus nerve. We present evidence of the existence of non-genital orgasms, which suggests that genital orgasm is a special case of a more pervasive orgasmic process. Through recent studies, the mechanisms and manifestations of love and its deprivation are becoming better understood. The better is our understanding of love, the greater is our respect for the significance and potency of its role in mental and physical health.     

Exochelin genes in Mycobacterium smegmatis: identification of an ABC transporter and two non-ribosomal peptide synthetase genes

Many strains of mycobacteria produce two ferric chelating substances that are termed exochelin (an excreted product) and mycobactin (a cell-associated product). These agents may function as iron acquisition siderophores. To examine the genetics of the iron acquisition system in mycobacteria, ultraviolet (UV) and transposon (Tn611) mutagenesis techniques were used to generate exochelin-deficient mutants of Mycobacterium smegmatis strains ATCC 607 and LR222 respectively. Mutants were identified on CAS siderophore detection agar plates. Comparisons of the amounts of CAS-reactive material excreted by the possible mutant strains with that of the wild-type strains verified that seven UV mutant strains and two confirmed transposition mutant strains were deficient in exochelin production. Cell-associated mycobactin production in the mutants appeared to be normal. From the two transposon mutants, the mutated gene regions were cloned and identified by colony hybridization with an IS6100 probe, and the DNA regions flanking the transposon insertion sites were then used as probes to clone the wild-type loci from M. smegmatis LR222 genomic DNA. Complementation assays showed that an 8 kb PstI fragment and a 4.8 kb PstI/SacI subclone of this fragment complemented one transposon mutant (LUN2) and one UV mutant (R92). A 10.1 kb SacI fragment restored exochelin production to the other transposon mutant (LUN1). The nucleotide sequence of the 15.3 kb DNA region that spanned the two transposon insertion sites overlapped the 5' region of the previously reported exochelin biosynthetic gene fxbA and contained three open reading frames that were transcribed in the opposite orientation to fxbA. The corresponding genes were designated exiT, fxbB and fxbC. The deduced amino acid sequence of ExiT suggested that it was a member of the ABC transporter superfamily, while FxbB and FxbC displayed significant homology with many enzymes (including pristinamycin I synthetase) that catalyse non-ribosomal peptide synthesis. We propose that the peptide backbone of the siderophore exochelin is synthesized in part by enzymes resembling non-ribosomal peptide synthetases and that the ABC transporter ExiT is responsible for exochelin excretion.     

Genetic basis of neurological tumours

Neurological tumours are common neoplasms of both adults and children. Recent studies have begun to delineate the genetic abnormalities that underlie such tumours, and have implicated two classes of genes, oncogenes and tumour suppressor genes. Most investigations have focused on those astrocytomas that affect the cerebral hemispheres of adults, since these are the most common and malignant brain tumours. The high-grade astrocytomas that affect adults, such as glioblastoma multiforme, often have amplification of the epidermal growth factor receptor (EGFR) oncogene and loss of a variety of chromosomal loci that probably harbour tumour suppressor genes. Of the various tumour suppressor gene loci, the p53 gene on chromosome 17p has been studied most closely and has been shown to be mutated in both low- and high-grade astrocytomas. These genetic alterations may provide a means for subdividing astrocytomas into diagnostic categories. For instance, p53 gene mutations occur more commonly in glioblastomas from young adults and women, while EGFR gene amplification is more common in glioblastomas from older adults and men. For the other primary CNS tumours, genetic studies remain in their infancy. The neurocutaneous syndromes, such as neurofibromatosis types 1 and 2, have provided unique insights into neurological oncogenesis. The NF1 gene on chromosomes 17q and its product, neurofibromin, may be important in the formation of neurofibrosarcomas, while the NF2 gene on chromosome 22q and its product, merlin, are probably involved in the formation of schwannomas and other nervous system tumours. The further characterization of these and other neurological tumour genes will undoubtedly illuminate many other areas in neurooncology.     

Water-Acetonitrile Ratio in Perchlorate Cadmium Bath and the Effectiveness of the Addition of Crown-Ester

It is shown that the strongest deceleration of the electrodeposition of cadmium in inhibited media is observed in the domain of loosening the structure of a mixed solvent (0.45 x ₂ 0.25) when the molecular adsorption of organic solvent on Cd is maximum. The process is maximally facilitated in the domain of ordering the acetonitrile's (AN) structure (0.9 x ₂ 0.75), where perchlorate anions dominate at the cathode surface. Crown-ester exhibits maximum inhibition effect under the conditions of preferential adsorption of its molecules, i.e., in the domain of the prevalence of the nonaqueous component in the mixture (x ₂ 0.95).     

Wear of magnesia spinel refractories in portion vacuum-processing steel plant

Conclusions The processes of wear in the lining of vacuum chambers of outdoor-furnace vacuum-treatment plants (UPVS) are due to the simultaneous action of high temperatures, deep vacuum, gaseous medium, molten metal, and slag. The corrosion and erosion of aggressive melts of slag and metal are the decisive forms of wear.Laboratory investigations established the relationship between slag resistance in vacuum and the ratio of corrosive and erosive constituents in the wear of different magnesia-spinel refractories and their phase composition, structure, and properties.Refractories obtained from fused periclase-chromite material with a low content of fusible silicates showed that in laboratory vacuum equipment and during service in the linings of the vaccum chamber of industrial plant they have higher slag resistance and lower wear than refractories based on sintered magnesite, spinel, and chromite ores.Translated from Ogneupory, No. 3, pp. 14–21, March, 1980.     

Development of monolithic catalysts with low noble metal content for diesel vehicle emission control

Topics in Catalysis - Monolith washcoated catalysts with potential for diesel emission control have been developed. Two types of catalysts have been prepared for further study: (1) MnO x supported...     

Predicting external sulphur requirement of alfalfa from sulphate sorption isotherm of Tanzanian soils

For Tanzanian soils dominant in hydrous oxides of iron and amorphous ferri-alumino silicate, a 48-hour (hr) mixing period with the sulphate (SO₄) solution was adequate for a near-equilibrium condition. Although differing in their SO₄ sorption capacity, all the soils sorbed SO₄ at or beyond 1µg ml^–1 sulphur (S) concentration in the supernatant. Hydroxyl (OH) ions were displaced during SO₄ sorption as indicated by a significant positive correlation between the amount of sorbed SO₄ and the difference in pH values determined in 0.1N K₂ SO₄ and 0.1N KCl, i.e. the dpH values.In a greenhouse experiment, alfalfa was grown on eight soils at six adjusted S concentrations. Sulphur deficiency symptoms appeared in the control pots of those soils which were low in native sorbed SO₄, SO₄ sorption capacity and initial soil solution S concentration. Sulphur fertilization increased dry matter (DM) yield as well as response to applied S. The external S concentration, i.e. adjusted S concentration required for 95% of the maximum DM yield, ranged from 0.8 to 8.2µg S ml^–1 with values less than 2.0 on most of the soils. The external S concentration decreased hyperbolically as the SO₄ sorption capacity of the soils increased. The total amount of fertilizer S required to obtain the external S concentration in solution, and at the same time satisfy the SO₄ sorption capacity of the soil at the external S concentration (determined from the sorption isotherm) was defined as the external S requirement for the specified yield level of alfalfa. The external S requirement for 95% of the maximum yield of alfalfa varied from soil to soil due to differences in their capacity and intensity for S nutrition.Part of a thesis by the senior author for the MSc (Agric) degree of the University of Dar es Salaam