Sulphonate buffers affect the recovery of microtubule-associated proteins MAP1 and MAP2: evidence that MAP1A promotes microtubule assembly

The influence of two commonly used sulphonate buffers, PIPES and MES, on the in vitro assembly of bovine brain microtubule protein was examined. Microtubule assembly was monitored by turbimetry and, after centrifugation, the polymerised protein was analysed by SDS-PAGE and western blotting. Assembly in MES when compared with PIPES resulted in a higher recovery of microtubule proteins at both pH 6.4 and pH 6.9 and in an altered protein composition. The buffer pH affected the total amount of protein polymerised but did not significantly affect the protein composition. At both pH conditions the recovery of HMW-MAPs was markedly increased in MES buffer and this increase was mostly due to an increase in the amount of MAP1.     

Reaction of the cardio-respiratory-system following acetylcholine inhalation and the dependency from the body position on anaesthetised dogs (author's transl)

The bronchomotoric reaction following ACH-aerosol in low concentrations is dependend on the position of the body on dogs. Up till one maximal reaction the increase of the airway resistance is always stronger in the lateral position. Nevertheless the breathing minute volume is constant. Concentration reaction curves will be shown. Arterial blood gases, heart rate, and pressure in the arteria femoralis were also measured. The different strongness of the reaction following ACH-inhalation will be caused by the predominantely unilateral ventilation of the animals in the lateral position.     

Use of silica gel for improving waterflooding performance of bottom-water reservoirs

This research addresses the problem of waterflooding a medium-gravity of oil-bearing formation with a water leg, and offers recommendations for process selection. In many reservoirs the presence of a bottom-water zone results in a very poor areal and vertical sweep efficiencies. However, waterflooding still remains the most widely used oil-recovery technique for these reservoirs. Waterflood performance in these reservoirs can be improved greatly with effective methods of partially plugging the bottom-water zone. One such method is the use of CO₂-activated silica gel as a blocking agent in the presence of a bottom-water zone.Thirteen large-model experiments were conducted using silica gel, to study the effect of oil-to-water zone permeability contrast and thickness ratio, oil viscosity, and CO₂ injection. A qualitative comparison is made to show the relative merit of CO₂-activated silica gel injection among other mobility control agents. Several runs were conducted to study silica gel rheology both in presence and in absence of CO₂.     

Temperature-dependent studies on the electrical properties of pyrolytic ZnO thin film prepared from Zn(C2H3O2)2

Pyrolytically deposited transparent conducting zinc oxide thin films on glass substrates were successively subjected to a post-deposition heat treatment in air and in vacuum. The effects of heat treatment on the electrical transport properties were studied in detail. The films were polycrystalline in structure and the oxygen chemisorption-desorption process was found to play an important role in controlling the electronic properties. Various grain-boundary and energy-band parameters were calculated by taking conventional extrinsic semiconductor theory and grain-boundary trapping models into account. The samples were non-degenerative at room temperature and Hall mobility was found to be modulated by the grain-boundary potential barrier height via sample temperature.     

Immunogenetics of episcleritis in leprosy

BACKGROUND: Neurenteric cysts are rare endothelium-lined structures. Two patients with symptomatic neurenteric cysts at the craniovertebral junction are presented. CASE PRESENTATION: Intermittent progression of neurologic symptoms delayed diagnosis for both patients. In one case, marked enlargement of the cyst was detected on serial imaging studies, and pathological examination of the excised lesion indicated rupture of the cyst. These cysts were totally resected by transoral or suboccipital approaches, as they were not firmly adherent to surrounding neural structures. The diagnosis of neurenteric cyst was confirmed by immunohistochemical analysis of the cyst wall. CONCLUSION: In view of the clinical course of these patients, we recommend early surgical resection of neurenteric cysts located at the craniovertebral junction.     

Antibiotics MDL 62,879 and kirromycin bind to distinct and independent sites of elongation factor Tu (EF-Tu)

Antibiotic MDL 62,879 inhibits bacterial protein synthesis by acting on elongation factor Tu (EF-Tu). In this study we show that the inhibition of protein synthesis by MDL 62,879 in an Escherichia coli cell-free system was fully reversed by addition of stoichiometric amounts of EF-Tu but not by large excesses of EF-Ts, ribosomes, or aa-tRNA. MDL 62,879 bound tightly to EF-Tu and formed a stable 1:1 MDL 62,879:EF-Tu (M:EF-Tu) complex. We show that binding of MDL 62,879 to EF-Tu strongly affects the interaction of EF-Tu with aa-tRNA and causes rapid dissociation of preformed EF-Tu.aa-tRNA complex, suggesting that inhibition of aa-tRNA binding is due to a conformational change in EF-Tu rather than competition for the aa-tRNA binding site. Indication of a conformational change in EF-Tu induced by MDL 62,879 is further confirmed by proteolytic cleavage experiments: MDL 62,879 binding strongly protects EF-Tu against trypsin cleavage. The observed effects of MDL 62,879 appear to be different from those of the kirromycin class of antibiotics, which also inhibit protein synthesis by binding to EF-Tu, suggesting two distinct binding sites. Indeed, the M:EF-Tu complex was able to bind stoichiometric amounts of kirromycin to form a 1:1:1 M:EF-Tu:kirromycin (M:EF-Tu:K) complex, providing direct evidence that the two antibiotics bind to independent and distinct sites on the EF-Tu molecule. The interaction of the M:EF-Tu:K complex with aa-tRNA and other co-factors suggest that the contemporary binding of the two antibiotics locks EF-Tu into an intermediate conformation in which neither antibiotic exhibits complete dominance.     

A novel dehumidification technique using electric field

A completely new concept of dehumidification is presented. The polar nature of the electronic bond structure between oxygen and hydrogen atoms in a water molecule is utilized to attract them using an electric field. It is possible to single out and remove the water molecules from the air inside a room to make the room dehumidified. A theoretical formulation is developed and a simple experiment was performed to validate the theory. Unlike the conventional dehumidification process, this process does not involve any condensation of the moisture and hence requires a very small amount of power. The technique can also be very useful for air-conditioning as well     

A random graph model for the final-size distribution of household infections

In epidemiological/disease control studies, one might be interested in estimating the parameters community probability infection (CPI) and the household secondary attack rate (SAR), as introduced by Longini and Koopman. The quasi-binomial distribution I (QBD I) with parameters n, p and theta, introduced by Consul, is proposed as a model for the final-size distribution of household infections, where p (CPI) is the probability of an individual being infected from the community and theta (SAR) is the rate of secondary transmission of infection within household. An individual can be infected either from within the household or from the community. Let X be the total number of infected members in a household of size n. Then the distribution of X is given by the QBD I with the probability mass function: (formula: see text) with 0 < p < 1, theta > or = 0 such that p + n theta < 1. The epidemic model is derived from a directed random graph. Data from influenza epidemics in Asian and American households are used to test the model and a comparison is made with the Longini-Koopman model. It is shown empirically that the QBD I is as good as the L-K model in describing the household infectious disease data, and both models provide almost identical estimates for community and household transmission parameters although they are derived from different perspectives and conditions.     

Solvent extraction of Ti(IV), Fe(III) and Fe(II) from acidic sulfate medium with di-o-tolyl phosphoric acid-benzene — hexan-1-ol system: A separation and mechanism study

The extraction of Ti(IV), Fe(III) and Fe(II) with di-o-tolyl phosphoric acid (HDTP, HA)-benzene-20% hexan-1-ol system was studied as function of contact time, concentrations of extractant in the organic phase and of H₂SO₄ in the aqueous phase, and temperature. The order of extractability under identical conditions is: Ti(IV) > Fe(III) ? Fe(II). The relative separations of these metal ions are also dependent on the above four factors. The maximum values of the separation factors, $\text{β}{}_1\text{=}\text{E}{}_{\mathrm{<mtext>Ti(IV)</mtext>}}{}^0\text{E}{}_{\mathrm{<mtext>Fe(IlI)</mtext>}}{}^0\text{= 175}$ at 0.10 M HDTP and 3.50 M H₂SO₄ concentrations, and $\text{β}{}_2\text{=}\text{E}{}_{\mathrm{<mtext>Ti(IV)</mtext>}}\text{E}{}_{\mathrm{<mtext>Fe(II)</mtext>}}{}^0\text{= 7800}$ at 0.10 M HDTP and 0.50 M H₂SO₄ concentrations, indicate that the separation of Ti(IV) from iron seems to be promising if iron is present in the divalent state. The mechanisms of extraction are discussed.