The influence of water hardness perturbations on bubble departure dynamics.

The influence of small changes to water hardness on the nonlinear behaviour of liquid penetration into a capillary and the resulting air pressure fluctuations during air bubble formation are examined in this paper. Experiments were undertaken in which bubbles were generated both in water having a surface tensile force of σ = 72.2 mN/m and in an aqueous solution of calcium carbonate having a surface tensile force of σ = 75.4 mN/m, each contained in a glass capillary with an internal diameter of 1 mm. It is shown that both the maximum value of liquid penetration into the capillary and bubble growth time are affected by perturbations to the water hardness. The time it takes for the bubble to depart the capillary was estimated using the following nonlinear data analysis methods: time delay (τ), attractor reconstructions, correlation dimension (D), and largest Lyapunov exponent (λ). All estimates demonstrate that the pressure fluctuations in the c-c aqueous solutions and extent of liquid solution penetration into the capillary during the time between subsequent bubble departures behave chaotically. Furthermore, this work demonstrates that the dynamics of bubble formation along with the bubble waiting time are very sensitive to small perturbation in the physical properties of the liquid, and this sensitivity has a significant effect on the observed chaotic behaviour.

Procedures for risk-stratification of lung cancer using buccal nanocytology.

Lung cancer is the leading cause of cancer deaths in the U.S. with survival dramatically depending on stage at diagnosis. We had earlier reported that nanocytology of buccal cells can accurately risk-stratify smokers for the presence of early and late-stage lung cancer. To translate the technique into clinical practice, standardization of operating procedures is necessary to consistently yield precise and repeatable results. Here, we develop and validate simple, robust, and easily implementable procedures for specimen collection, processing, etc. in addition to a commercially-viable instrument prototype. Results of this work enable translation of the technology from academic lab to physicians' office.

Tautomerism of 2-azidoadenine nucleotides. Effects on enzyme kinetics and photoaffinity labeling.

The 2-azidoadenine nucleotides show promise as photoaffinity probes. Substitution at the C-2 position should favor an anti conformation and enable binding of the analogue to enzyme sites which exhibit low affinity for the 8-azidoadenine derivatives. The 2-azidoadenine nucleotides were found to be substrates for pyruvate kinase, phosphofructokinase, adenylate kinase, hexokinase and the mitochondrial F1-ATPase. However, tautomerism of 2-azidoadenine nucleotides to two nonphotoreactive tetrazole forms complicates kinetic analyses and their use as photoaffinity probes. An analysis of the ultraviolet spectra of these analogues enables an estimation of the tetrazolo isomer content and the rates of tautomerization. The photoreactive azido isomer was found to represent only 45% of the total analogue population in neutral aqueous solution. The azidoazomethine-tetrazole equilibrium favors the azido isomer in acidic or nonpolar solutions. The first-order rate constants at 25 degrees C were determined to be 0.017 min-1 and 0.021 min-1 for tautomerism to the azido and tetrazolo isomers, respectively. Prior equilibration of the probe in various solvents thus allows investigation of the analogue's behavior with an enzyme system at different, essentially fixed, isomer ratios. The determination of the impact of the tetrazolo tautomers on the system allows optimization of conditions for photoaffinity-labeling experiments.

Photoaffinity labeling of the tight ADP binding site of the chloroplast coupling factor one (CF1): the effect on the CF1-ATPase activity.

Chloroplast thylakoid membranes contain tightly bound ADP which is intimately involved in the mechanism of photophosphorylation. The photoaffinity analog 2-azido-ADP binds tightly to spinach thylakoid membrane-bound coupling factor one (CF1) and, in a manner similar to ADP, inhibits the light-triggered ATPase activity (Czarnecki, J.J., Abbott, M.S. and Selman, B.R. (1983) Eur. J. Biochem. 136, 19-24). Ultraviolet irradiation of thylakoid membranes containing noncovalently, tightly bound 2-azido[beta-32P]ADP results in the inactivation of both the methanol-stimulated MgATPase activity of the membrane-bound CF1 and the octylglucoside-dependent MgATPase activity of the solubilized enzyme. There is a linear correlation between the loss of enzyme activity and the covalent incorporation of the photoaffinity analog. Full inactivation of catalytic activity is estimated to occur upon incorporation of 1.07 mol analog and 0.65 mol analog per mol enzyme for the methanol- and octylglucoside-stimulated activities, respectively. Since 2-azido-ADP modifies only the beta subunit of the CF1 and since there are probably three beta subunits per CF1, these results indicate strong cooperativity among beta subunits and between the site of tightly bound nucleotides and the catalytic sites.

Effect of thymosin peptides on the chick chorioallantoic membrane angiogenesis model.

The effect of alpha- and beta-thymosin peptides, namely prothymosin alpha (ProT(alpha)), thymosin alpha(1) (T(alpha)1), parathymosin alpha (ParaT(alpha)), thymosin beta(4) (Tbeta4), thymosin beta(10) (Tbeta10), and thymosin beta(9) (Tbeta9), on the angiogenesis process was investigated using the chick chorioallantoic membrane as an in vivo angiogenesis model. The thymosin peptides tested were applied in 10 microl aliquots containing 0.01-4 nmoles of Tbeta4, Tbeta10 or Tbeta9, 0.016-6.66 nmoles of T(alpha)1, 4.1 pmoles-1.66 nmoles of ProT(alpha), and 4.4 pmoles-1.76 nmoles of ParaT(alpha). Phorbol 12-myristate 13-acetate and hydrocortisone were also used as positive and negative control, respectively. Tbeta4, ProT(alpha) and T(alpha)1 were found to enhance angiogenesis, while Tbeta10, Tbeta9 and ParaT(alpha) exhibited an inhibitory effect on the angiogenesis process. When mixtures of Tbeta4 and Tbeta10 containing active amounts of the two peptides at different proportions were applied, the promoting effect of Tbeta4 on angiogenesis was reversed in the presence of increasing concentrations of Tbeta10 and vice versa. The effect of Tbeta10, Tbeta9, ProT(alpha) and ParaT(alpha), in parallel with Tbeta4 and T(alpha)1, on the angiogenesis process was investigated for the first time as far as we know and the results of this study offer more insight into the biological regulatory roles of thymosin peptides, and provide helpful information about their therapeutic potential. Whether these agents could be used either as inhibitors of angiogenesis in disease states where uncontrolled angiogenesis is involved, e.g. in carcinogenesis, or as angiogenesis promoters that could be useful in wound healing, fracture repair, peptic ulcers etc., remains to be further studied.

Molecular cloning, characterization and expression of a novel retinal clusterin-like protein cDNA.

A novel gene expressed predominantly in retina, but detected at a conspicuously lower level in retina of canine progressive rod cone degeneration (prcd), has been identified by suppression subtractive hybridization and retinal cDNA library screening. The characterized region of cDNA of the novel gene includes 1017 nucleotides of coding sequence predicted to encode a protein of 338 amino acids (M(r) 39389), 791 nucleotides of 5'-untranslated region (UTR), and 300 nucleotides of 3'-UTR including the poly(A)(+) tail. Multiple transcripts were detected in retina by Northern blot analysis, and a lower level of expression was observed in brain and liver by RT-PCR. The transcript appears to be developmentally regulated with a burst in gene expression at a time period (34 postnatal days) that coincides with the photoreceptor differentiation phase of retinal development. The deduced amino acid sequence from the cDNA of the novel gene has 24% identity and 48% similarity with the multifunctional glycoprotein clusterin. Hence, the putative gene product from the novel transcript has been named clusterin-like protein 1 (CLUL1). The human homologue of CLUL1 cDNA has 84 and 70% identity at the level of nucleotides and amino acids, respectively, with the characterized canine cDNA. The presence of a stretch of 128 amino acids in the putative human CLUL1, not detected in canine CLUL1, suggests alternate splicing events. An STS database search revealed that the human homologue of CLUL1 maps to chromosome 18p, a location not yet reported to harbor an RP locus. Tissue-specific expression of CLUL1 in retina, and its lower abundance in different forms of PRA suggest that this novel gene may represent an as-yet unidentified locus for a retinal disorder.

Distinguishing postganglionic from preganglionic lesions. Studies in rabbits with surgically produced Horner's syndrome.

It has been suggested that the pupillary response to hydroxyamphetamine hydrobromide eyedrops will separate distal from proximal lesions of the sympathetic pathway from the brain to the eye (the pupil fails to dilate in postganglionic lesions). We studied the pupillary response to hydroxyamphetamine in two groups of rabbits with surgically produced Horner's syndrome. Rabbits in one group had postganglionic lesions. In all animals, a miotic pupil developed ipsilateral to the surgical lesion, and oculosympathetic paresis was confirmed in each by testing pupillary response to topically applied cocaine. In rabbits with postganglionic lesions, hydroxyamphetamine failed to dilate the miotic (Horner's) pupils as well as it dilated the normal pupils, while in rabbits with preganglionic lesions both miotic and normal pupils dilated equally. Hydroxyamphetamine appears to be a diagnostically useful drug in Horner's syndrome.

The iris sphincter in aberrant regeneration of the third nerve.

Fourteen patients with aberrant regeneration of the third cranial nerve were examined using self-developing photographs, motion pictures, and pupillography. These pupillary phenomena were noted: (1) sector contractions of the iris sphincter in response to light, (2) sector contractions of the iris sphincter associated with eye movements, and (3) an abnormal pupillary unrest. The observations strongly support the concept that after injury, fibers regenerate and sprout collateral branches that finally reach muscles of the oculomotor group other than those originally innervated.

Spontaneous cyclic segmental sphincter spasms in an Adie's tonic pupil.

A 43-year-old woman with bilateral Adie's tonic pupils had a segment of one iris sphincter that contracted spontaneously every few seconds, but was not influenced by light, near vision, or eye movements.

Tadpole-shaped pupils caused by segmental spasm of the iris dilator muscle.

Segmental spasms of the iris dilator muscle produce intermittent pupillary distortion. A study of 26 case histories (six previously reported and 19 reported for the first time) showed that the episodes are brief (lasting less than five minutes in 23 of 26 patients, less than two minutes in 18 patients, and less than one minute in eight patients) but can occur several times a day. The patients ranged in age from 24 to 48 years (the age of one patient was not known); five were men and 21 were women. Eleven patients had Horner's syndrome, four had Adie's tonic pupil, and eight had definite or probable migraine (another three had possible migraine). The episodes eventually stopped, leaving no serious sequelae. Focal application of phenylephrine produced a similar distortion in a normal human eye.

The influence of the thymic preparation thymex-L on deficient antitumor-activity of monocytes from melanoma patients in-vitro.

Recently we demonstrated that, in vitro, prothymosin alpha 1 (ProT alpha), a polypeptide from calf thymus, was able to enhance the deranged tumoristatic activity of peripheral blood monocytes from melanoma patients. Now we report, that the thymic preparation Thymex-L significantly enhanced the level of depressed monocyte activity from 19% to 26%, whereas in normal donor groups no significant change of basal activity (35%) was seen. Although the improvement of median levels of killer cell activity was found to be independent from the disease stage, the Thymex-L effect was only statistically significant in stage I and melanoma patients after chemotherapy. In contrast to ProT alpha, Thymex-L did not further enhance monocyte-mediated cytotoxicity when it was applied in combination with rIFN-gamma. However, after stimulation with rIFN-gamma, the median level of TNF-alpha secretion by melanoma monocytes significantly increased (about 2-fold) when preincubated with Thymex-L. These results indicate that depressed monocyte functions in selected melanoma patients may be partially improved by Thymex-L.

Shear-induced coalescence of emulsified oil drops.

Crude oil droplets, when suspended in water, possess negative surface charges which give rise to double-layer repulsive forces between the drops. According to conventional DLVO theory, the magnitude of this repulsion (based on the measured zeta potential) is more than sufficient to prevent coalescence of the droplets. Indeed, when two such droplets were brought together on direct (i.e., "head-on") approach, coalescence was rarely observed. Upon oblique approach, however, the same droplets were seen to coalesce readily. An oblique encounter must necessarily give rise to lateral relative motion-or shearing-between the droplet surfaces. It is speculated that, if the charge distributions at the droplet surfaces were heterogeneous, lateral shearing would facilitate many encounters between surface patches of different zeta potentials across the intervening water film. If the repulsion across any local region were sufficiently weak to allow formation of an oil bridge across the water film, coalescence of the drops would follow inevitably. With the hypothesis of surface heterogeneity, it is not necessary to invoke any additional colloidal interactions (such as "hydrophobic forces") to account for the observed droplet-droplet coalescence. This finding may have important implications for the underlying mechanisms of emulsion stability in general and the commercial extraction of bitumen from oil sands in particular.

Dynamic and static interactions between bitumen droplets in water.

In the commercial bitumen extraction operation, dynamic and static interaction forces between bitumen drops in water determine the likelihood of desirable bitumen coalescence at different process stages. These dynamic and static forces were measured using colloidal particle scattering and hydrodynamic force balance techniques, respectively. In the former technique, dynamic interactions are studied through droplet-droplet collision trajectory measurement. In the latter technique, the static attractive forces between droplets are determined when a doublet is separated with a known and adjustable hydrodynamic force. The dynamic force measurement implies the presence of rigid chains on bitumen surfaces. The mean chain lengths for deasphalted bitumen at pH 7, whole bitumen at pH 7, and whole bitumen at pH 8.5 are 50, 78, and 41 nm, respectively. However, the static force measurement indicates much shorter mean chain lengths (<9 nm) in these three bitumen systems. Shorter chain length indicates weaker repulsive force. This finding of a much weaker repulsion between bitumen droplets under static conditions has important implications on the commercial bitumen extraction operation.

The pupil in stroke.

Pupil sizes were assessed in 100 patients admitted to an intensive care stroke unit over a 1-year period to determine if differences existed and if anisocoria might help in diagnosis. From life-size photographs the pupil diameters were measured accurately, and clinical information compiled by the neurology staff was studied. Of the 19 patients with anisocoria 13 had a final diagnosis of stroke. This incidence of anisocoria, 16%, is similar to that in a normal population (20%). The side of the mydriasis was unrelated to the site of the lesions except when the stroke was due to a brainstem infarction; then ipsilateral Horner's syndrome occurred.

Alternating Horner's syndrome: is it or isn't it?

Two cases of so-called alternating Horner's syndrome are presented. Pupillary testing with cocaine and hydroxyamphetamine failed to reveal whether the problem was due to a lesion that shifted and thus had a truly alternating effect or whether it was due to a one-sided lesion that was at times hypoactive and at other times irritative.

The analysis of anisocoria. The use of photography in the clinical evaluation of unequal pupils.

Unequal pupils are common and can be difficult to sort out. A flow chart is presented to help in localizing the cause for anisocoria. Also, an inexpensive and simple camera is suggested for use in accurately measuring pupils.

"Twin peaks" papilledema: the appearance of papilledema with optic tract atrophy.

A woman with a right middle fossa meningioma causing right optic tract atrophy and papilledema had distinctive funduscopic changes. The ipsilateral eye showed temporal disc pallor and nasal edema. The contralateral disc showed edema of the upper and lower poles which was separated by a horizontal band of optic atrophy. The fluorescein angiographic changes clearly illustrate this pattern. Apart from its theoretical interest this appearance of papilledema and atrophy provides definite localizing information.

How acoustic cavitation can improve adhesion.

In general, ultrasound is commonly used at low power level for non-destructive testing (NDT) and detection of delaminations in adhesive bonded structures. The present paper instead presents an approach where power ultrasound is used to improve interface formation prior to the bonding process and to ensure the quality of adhesive bonds by using acoustic cavitation in the liquid adhesive. Results from high-speed videos, rheological and thermal measurements and destructive testing of adhesive bonds with contaminated surfaces are presented and discussed. Power ultrasound can be used in general to improve adhesion and significantly to improve contamination tolerance and robustness of adhesive bonding processes.