Dynamics of a vesicle in general flow.

An approach to quantitatively study vesicle dynamics as well as biologically-related micro-objects in a fluid flow, which is based on the combination of a dynamical trap and a control parameter, the ratio of the vorticity to the strain rate, is suggested. The flow is continuously varied between rotational, shearing, and elongational in a microfluidic 4-roll mill device, the dynamical trap, that allows scanning of the entire phase diagram of motions, i.e., tank-treading (TT), tumbling (TU), and trembling (TR), using a single vesicle even at lambda = eta(in)/eta(out) = 1, where eta(in) and eta(out) are the viscosities of the inner and outer fluids. This cannot be achieved in pure shear flow, where the transition between TT and either TU or TR is attained only at lambda>1. As a result, it is found that the vesicle dynamical states in a general are presented by the phase diagram in a space of only 2 dimensionless control parameters. The findings are in semiquantitative accord with the recent theory made for a quasi-spherical vesicle, although vesicles with large deviations from spherical shape were studied experimentally. The physics of TR is also uncovered.

Complex refractive indices of aerosols retrieved by continuous wave-cavity ring down aerosol spectrometer.

The major uncertainties associated with the direct impact of aerosols on climate call for fast and accurate characterization of their optical properties. Cavity ring down (CRD) spectroscopy provides highly sensitive measurement of aerosols' extinction coefficients from which the complex refractive index (RI) of the aerosol may be retrieved accurately for spherical particles of known size and number density, thus it is possible to calculate the single scattering albedo and other atmospherically relevant optical parameters. We present a CRD system employing continuous wave (CW) single mode laser. The single mode laser and the high repetition rate obtained significantly improve the sensitivity and reliability of the system, compared to a pulsed laser CRD setup. The detection limit of the CW-CRD system is between 6.67 x 10(-10) cm(-1) for an empty cavity and 3.63 x 10(-9) cm(-1) for 1000 particles per cm(3) inside the cavity, at a 400 Hz sampling and averaging of 2000 shots for one sample measurement taken in 5 s. For typical pulsed-CRD, the detection limit for an empty cavity is less than 3.8 x 10(-9) cm(-1) for 1000 shots averaged over 100 s at 10 Hz. The system was tested for stability, accuracy, and RI retrievals for scattering and absorbing laboratory-generated aerosols. Specifically, the retrieved extinction remains very stable for long measurement times (1 h) with an order of magnitude change in aerosol number concentration. In addition, the optical cross section (sigma(ext)) of a 400 nm polystyrene latex sphere (PSL) was determined within 2% error compared to the calculated value based on Mie theory. The complex RI of PSL, nigrosin, and ammonium sulfate (AS) aerosols were determined by measuring the extinction efficiency (Q(ext)) as a function of the size parameter ((piD)/lambda) and found to be in very good agreement with literature values. A mismatch in the retrieved RI of Suwannee River fulvic acid (SRFA) compared to a previous study was observed and is attributed to variation in the sample composition. The small system presented delivers high ability for fast measurements and accurate analysis, making it a good candidate for field aerosol optical properties studies.

Photoluminescence ring formation in coupled quantum wells: excitonic versus ambipolar diffusion.

In this Letter, we study the diffusion properties of photoexcited carriers in coupled quantum wells around the Mott transition. We find that the diffusion of unbound electrons and holes is ambipolar and is characterized by a large diffusion coefficient, similar to that found in p-i-n junctions. Correlation effects in the excitonic phase are found to significantly suppress the carriers' diffusion. We show that this difference in diffusion properties gives rise to the appearance of a photoluminescence ring pattern around the excitation spot at the Mott transition.

Mixing by polymers: experimental test of decay regime of mixing.

By using high molecular weight fluorescent passive tracers with different diffusion coefficients and by changing the fluid velocity we study the dependence of a characteristic mixing length on the Peclet number, Pe, which controls the mixing efficiency. The mixing length is found to be related to Pe by a power law, L(mix) proportional, variant Pe0.26+/-0.01, and increases faster than expected for an unbounded chaotic flow. The role of the boundaries in the mixing length abnormal growth is clarified. The experimental findings are in good quantitative agreement with recent theoretical predictions.

Naproxen sodium (Anaprox): pharmacology, pharmacokinetics and drug interactions.

Naproxen sodium (Anaprox) is a potent antiinflammatory and analgesic agent. The drug has demonstrated a variety of biologic actions, including stabilization of lysosomal membranes, but most of its therapeutic activity is probably mediated through prostaglandin synthesis inhibition. The linkage between inhibition of prostaglandin synthesis and relief of dysmenorrhea has been documented in clinical studies, reported elsewhere in this supplement. Of relevance is the selective activity of naproxen sodium on uterine microsomal preparations. Once dissolved in biologic fluids, naproxen and naproxen sodium are chemically identical species and have the same biologic properties. Administration of naproxen as the sodium salt (Anaprox), however, permits more rapid absorption from the gastrointestinal tract. In either form, the drug is essentially completely absorbed. Its metabolic half-life averages 13 hours. The metabolism of naproxen is quite simple: it is excreted almost entirely in the urine as the native molecule, its oxidative 6-desmethyl metabolite and their respective conjugates. Naproxen is an acidic drug that is highly bound to plasma albumin. It may thus be expected to displace and transiently increase the tissue availability of other protein-bound drugs. In practice, however, potential interactions with both warfarin and tolbutamide have been evaluated and do not appear to be of clinical significance. Naproxen has a high therapeutic index and a shallow dose-response curve, so the effect of other drugs on its pharmacokinetics is not likely to have a large clinical impact.

Bioavailability of naproxen sodium and its relationship to clinical analgesic effects.

1 In the first of a series of trials with naproxen sodium it was shown that patients achieved significantly earlier and higher plasma levels of naproxen when naproxen sodium was administered. 2 In a second study comparing naproxen with naproxen sodium in patients with post-partum pain, pain intensity was consistently lower for the group receiving naproxen sodium. However, statistically significant differences were not seen until 4 to 5 h after medication. 3 A final study documented that a more frequent dosage schedule of every 6 h led to clearly higher plasma levels than those achieved with an every 8 h regimen; plasma levels did not plateau. Doses up to 1,375 mg/day were well tolerated. 4 In conclusion, naproxen sodium appears to be an improved form of naproxen for use as a analgesic agent.

Comparative analgesic effects of naproxen sodium, aspirin, and placebo.

The analgesic efficacy of a single 550-mg dose of naproxen sodium was compared with that of 650 mg aspirin and a placebo in a double-blind, parallel trial. The study was carried out in an industrial setting and included 201 adult patients with various acute pain states. Musculoskeletal pain was the most common type of pain treated. Pain intensity differences and patients' evaluation of pain relief indicated statistically significantly earlier and better analgesia with naproxen sodium than with both aspirin and placebo. The summed pain intensity differences (SPID) showed that naproxen sodium performed better than aspirin, which in turn did better than placebo. the difference between naproxen sodium and aspirin means for SPID was numerically equal to the difference between the aspirin and placebo means for SPID. Further, the incidence of side effects was less with naproxen sodium than with aspirin. The study demonstrated that naproxen sodium provided earlier and better pain relief than aspirin, that this effect was consistent over time, and that the incidence of side effects associated with naproxen sodium was less than with aspirin.

Cloprednol bioavailability in humans.

The bioavailability of cloprednol, a new systemic corticosteroid, was examined in a 12-subject crossover study in which two capsules, a tablet, and a solution were tested. Plasma was analyzed for cloprednol by a GLC-mass spectrometric method. The biological half-life, peak plasma concentration, peak time, plasma concentration at all sampling times, and plasma areas were evaluated for differences (p less than or equal to 0.05) in comparisons of pairs among the four formulations. An analysis of variance revealed that cloprednol was absorbed to the same extent from all formulations and rapidly cleared from the plasma with a half-life of 1.86 +/- 0.36 (SD) hr. All plasma profile parameters from the solid dose formulations were the same, demonstrating bioequivalence in both rate and extent of absorption. Significant differences were observed between the solution and solid dose formulations with respect to peak time, 15-min plasma concentration, and 0-30 min area, indicative of faster absorption from the solution; however, total plasma areas were the same for all four formulations. Comparison of plasma cloprednol levels in this study to those of a prior intravenous-oral dose study suggests that cloprednol was completely bioavailable from all formulations.

The treatment of dysmenorrhea with naproxen sodium: a report on two independent double-blind trials.

The efficacy of naproxen sodium (naproxen-Na) in dysmenorrhea has been established in two independent double-blind (placebo-controlled) studies. An initial dose of 550 mg. of naproxen-Na was followed by 275 mg. every six hours for a maximum of five days. Twenty patients were included in Study I (10 treated with naproxen-Na) and 23 patients in Study II (12 treated with naproxen-Na). Each patient received the medication during four dysmenorrheic episodes. Thus, a total of 172 treatment courses could be evaluated. A variety of efficacy criteria were measured: frequency of pill intake, changes in pain intensity, the degree of relief achieved by the medication, and need for additional analgesics. In both studies naproxen-Na was demonstrated to be superior to the placebo treatment with high statistical significance in each of these parameters.

Pharmacokinetics of naproxen overdoses.

In earlier safety studies, naproxen, 600 mg three times daily, was administered to healthy subject without significant adverse effects. Another study demonstrated that single doses of 500 to 900 mg resulted in accelerated renal clearance and a nonlinear naproxen plasma level response after the higher doses. Our report describes the pharmacokinetics of naproxen when administered in single doses of 1, 2, 3, or 4 gm (up to eight times the clinically effective dose in rheumatoid arthritis) to healthy subjects. An increase in urinary excretion rate and continuation of the previously documented nonlinear plasma level response were observed. There were no signs that capacity to conjugate or to excrete the drug was exceeded. There were no adverse effects.

Combination therapy with naproxen and aspirin in rheumatoid arthritis.

Thirty-six patients with rheumatoid arthritis were studied to determine the effectiveness and safety of combined therapy with naproxen and aspirin. An 8-week double-blind crossover trial was performed in which naproxen and placebo were administered on a background of constant-dose aspirin. Combination therapy was demonstrated to be more effective than aspirin alone. Tolerance of the two regimens was comparable.

[Prospects of therapeutic intervention in drug addiction in prisons]. / Prospettive di intervento terapeutico sui tossicomani in carcere

The non-penalization envisaged by the new law concerning the use and possession of drugs, will not cause the population of drug addicts to disappear from the prisons; it is however to be expected a qualitative modification of them, with the drug addicts clinically in most serious and persistent conditions and more involved with the criminal subculture, gradually increasing in number. Such individuals will represent a group of potential customers much different from that found up to now, and their more meaningful features will concern their age (higher), polytoxicomania (almost always resulting in heroinism), the abandonment of all family ties, of the pristine social and cultural status, of work, to acquire a new role, where identity is extremely ambiguous and uncertain. As concerns the treatment hypotheses, the less involved users being no longer dealth with--upon whom the attention of operators had been chiefly centered, and on whom the prospects of a psychotherapeutic success had been founded--only two solutions are regarded as implementable in the future: either to give up all intramural treatments, with the exception of those having a medical character, and, extramurally, to provide for the supply (controlled and through dispensaries) of heroin or substitute drugs, so as to reduce as much as possible the danger drug addicts represent for society; or to establish therapeutic or intramural communities, forming the one instrument capable of suggesting or conditioning new identity patterns, as an initial stage of an analogous institutional treatment to be continued when the convict leaves the prison.

Metabolic effects of cloprednol-a new systemic corticosteroid.

The short-term metabolic effects of cloprednol, a new short-acting synthetic corticosteroid, were evaluated in four normal subjects. Cloprednol, 12.5 mg/day, in one subject had no appreciable effect on urinary excretion of sodium, potassium, nitrogen, or calcium. Cloprednol, 20 mg/day, in three subjects had no significant effect on mean daily urinary sodium and potassium excretion, although mild, transient sodium retention and kaliuresis were observed. One subject had increased nitrogen excretion and all three had a small increase in calcium excretion. Prednisolone, 40 mg/day, a dose with antiinflammatory potency equivalent to 20 mg/day cloprednol, given subsequently to two subjects under identical conditions resulted in sodium and potassium excretion results similar to those of cloprednol, 20 mg/day, but produced a much greater increase in nitrogen and calcium excretion. These results suggest that, like prednisolone, cloprednol lacks the sodium-retaining properties of hydrocortisone and raise the possibility that cloprednol has less of a deleterious effect on nitrogen and calcium excretion than prednisolone.