Flow of a liquid over large gas bubbles

An equation is given which allows calculation of the variation in size of a gas bubble as it moves through a liquid. It has been shown experimentally that the flow of a liquid over large deformed gas bubbles is not separated.     

Myelination in organotypic cultures of sympathetic ganglia

Explants of mouse superior cervical ganglion (SCG), co-cultured with dorsal spinal cord, were grown for up to 4 weeks in vitro. In such cultures, scattered internodes of peripheral nervous system (PNS) myelin were observed, apparently associated with SCG neurites. Although rare, the incidence of PNS myelination in this system might merit further experimentation to provide a model facilitating the evaluation of postganglionic sympathetic myelination, which in vivo may be both extensive and morphologically unusual.     

Derivatives of apomorphine and of other N-substituted norapomorphines

Derivatives of apomorphine and of N-n-propylnorapomorphine were prepared to obtain modified pharmacological activity and enhanced chemical stability. Mouse profile and dog emesis screens were performed, and the activity of various N-substituted derivatives and their esters was evaluated and compared to the parent compounds. The N-n-propyl diacetate derivative and N-methyl and N-n-propyl ascorbate salts were remarkably stable to air: apomorphine etherate was no more stable than the free base. The dimers, the major products formed during the acid-catalyzed rearrangement of morphines to apomorphines, were all potent emetics. Additionally, two showed a significant antagonism to morphine in mice and dogs.     

Oil well sand consolidation. I. Resins for a three-step process

Oil-bearing formations often consist of loose sandy material. In the production of oil from these formations sand tends to be carried to the well bore along with the oil. The flow of sand can be prevented by consolidating or cementing together the sand particles of the formation around the well bore. The cementing has to be accomplished in such a manner that fluid flow channels between particles remain open. This paper describes a new three-step process that was developed to consolidate oil well sand. The steps in the process involve injection of: (1) resin, (2) inert fluid, and (3) inert fluid containing a catalyst. In the first step of the process, resin in injected into the formation where it fully saturates the interstices between sand grains. Permeability is established in the second step by displacement of the excess resin from the interstices, thereby leaving a thin film of resin on the sand grains. In the third step, polymerization is activated by migration of catalyst from the inert fluid into the thin resin film on the sand. The process has the advantage that resin is placed and permeability is established before the resin is catalyzed. This avoids premature polymerization of the resin which might cause plugging of the formation or the tubing string used to inject resin. Desirable characteristics of a resin for the three-step process are: (1) viscosity of 25–200 cp. at well bore temperature; (2) stability for several days at well bore temperature; (3) high adhesion to sand in the presence of an inert flushing fluid; (4) polymerization by less than 10% catalyst; (5) the polymerized resin binds sand together with a strong bond that is not affected by well fluids. Five different resin types have been tested for use in the three-step sand consolidation process. These are: (1) epoxy–anhydride cured with a tertiary amine; (2) epoxy–epoxy diluent cured with a primary–tertiary amine mixture; (3) furan; (4) unsaturated polyester–vinylpyrrolidone; (5) unsaturated polyester–styrene. The two epoxy resins give strong, permeable consolidated sand which is resistant to well fluids such as brine and crude oil. The furan resin gives a weak consolidation. The unsaturated polyester–vinylpyrrolidone gives good strength and oil resistance but is sensitive to brine. The unsaturated polyester–styrene is difficult to apply. Many oil wells have been successfully treated in the Gulf Coast area and in California with the two epoxy resins. Almost all of these wells are producing free of sand, and, to date, more than five million barrels of oil have been produced from these wells.     

Comparative investigation of human stratum corneum ceramides

The stratum corneum (SC) requires ceramides, cholesterol, and fatty acids to provide the cutaneous permeability barrier. SC lipids can be analyzed by normal-phase high-performance thin-layer chromatography (HPTLC). However, without further analysis, some uncertainty remains about the molecular composition of lipids represented by every TLC band of an unknown sample. We therefore analyzed each ceramide band further by subjecting the isolated lipids to a direct coupling of reversed-phase high-performance liquid chromatography and electrospray ionization-mass spectrometry (HPLC/ESI-MS, or IC/MS). IC/MS analysis and ESI-MS/MS negative ion and collision-induced dissociation experiments revealed that ceramide band 4 contained not only N-(ω-OH-acyl)acyl-6-OH-sphingosine, Cer(EOH), but also N-(α-OH-acyl)-sphingosine. Band 5 exclusively contained N-acyl-6-OH-sphingosine. Our results demonstrate the benefit of LC/MS analysis for selective identification of human SC ceramides. Moreover, the combination of HPTLC for pre-separation and LC/MS for identification of lipids is an even more powerful tool for detailed ceramide analysis.     

GABA(A)-receptor subtypes: clinical efficacy and selectivity of benzodiazepine site ligands

Corticobasal degeneration (CBD) is a slowly progressive disorder characterized by an asymmetrical akinetic-rigid syndrome, supranuclear ophthalmoplegia, dystonia, often accompanied by involuntary movements, particularly myoclonus, and associated with lateralized cortical signs such as alien limb behavior and apraxia. Computerized tomography demonstrates asymmetrical frontoparietal cortical atrophy in the later stages of the illness. Neuropathological examination reveals neuronal loss, gliosis and swollen achromatic neurons within the frontal and temporal cortices, and the substantia nigra. We discuss here a unique phenomenon not described so far in three patients with clinical features of CBD, one with subsequent autopsy observations. When awake, they all showed a common behavior, their mouth opened constantly and immediately, when a tongue-depresser was approached in front of it by the examiner. In two of them, their mouth also opened when its corner was stroked by a tongue-depressor. They could not control these phenomena at all, even they were asked not to open their mouth. We would like to call these phenomena "forced mouth opening reactions" because they were uncontrollable voluntarily. They may be divided into two groups, i.e. visual and tactile "forced mouth opening reactions". In all the patients the neurological, neuro-imaging and neuropathological data showed that the frontal lobes were damaged. Additionally, they had some frontal lobe release signs such as forced grasping, forced groping, or alien limb sign. We would like to apply the mechanism for these release signs to the "forced mouth opening reactions". Thus, we speculate that the frontal lobe contains a higher motor control mechanism for normal mouth opening movement, and the "forced mouth opening reactions" result from impairment of this control.     

Clients and brothel managers in Kramat Tunggak, Jakarta, Indonesia: interweaving qualitative with quantitative studies for planning STD/AIDS prevention programs

Clients and brothel managers are often the most powerful decision-makers regarding condom use in brothels, but since publicly promoting condom use is still "culturally" difficult in Indonesia, the most feasible way of reaching clients is through the female commercial sex workers (FCSWs) and their managers. The existence of quasi-official brothel complexes in many major Indonesian cities, however, does make the government a key player in promoting condom use within these complexes. Interweaving qualitative with quantitative studies, this paper, which is part of a larger study, reveals the FCSWs' client/managers-related determinants of condom use. Policies that will promote condom use in brothel complexes are critical to the prevention of the spread of HIV throughout this community, as well as from it to the greater community.     

Differences in Ca2+ channels governing generation of miniature and evoked excitatory synaptic currents in spinal laminae I and II

Many neurons of spinal laminae I and II, a region concerned with pain and other somatosensory mechanisms, display frequent miniature "spontaneous" EPSCs (mEPSCs). In a number of instances, mEPSCs occur often enough to influence neuronal excitability. To compare generation of mEPSCs to EPSCs evoked by dorsal root stimulation (DR-EPSCs), various agents affecting neuronal activity and Ca2+ channels were applied to in vitro slice preparations of rodent spinal cord during tight-seal, whole-cell, voltage-clamp recordings from laminae I and II neurons. The AMPA/kainate glutamate receptor antagonist CNQX (10-20 microM) regularly abolished DR-EPSCs. In many neurons CNQX also eliminated mEPSCs; however, in a number of cases a proportion of the mEPSCs were resistant to CNQX suggesting that in these instances different mediators or receptors were also involved. Cd2+ (10-50 microM) blocked evoked EPSCs without suppressing mEPSC occurrence. In contrast, Ni2+ (相似文献