Fast dynamics and high effective dimensionality of liquid fluidity.

Fluidity, the ability of liquids to flow, is the key property distinguishing liquids from solids. This fluidity is set by the mobile transit atoms moving from one quasi-equilibrium point to the next. The nature of this transit motion is unknown. Here, we show that flow-enabling transits form a dynamically distinct sub-ensemble where atoms move on average faster than the overall system, with a manifestly non-Maxwellian velocity distribution. This is in contrast to solids and gases where no distinction of different ensembles can be made and where the distribution is always Maxwellian. The non-Maxwellian distribution is described by an exponent [Formula: see text] corresponding to high dimensionality of space. This is generally similar to extra synthetic dimensions in topological quantum matter, albeit higher dimensionality in liquids is not integer but is fractional. The dimensionality is close to 4 at melting and exceeds 4 at high temperature. [Formula: see text] has a maximum as a function of temperature and pressure in liquid and supercritical states, returning to its Maxwell value in the solid and gas states.

Universal interrelation between dynamics and thermodynamics and a dynamically driven "c" transition in fluids.

Our very wide survey of the supercritical phase diagram and its key properties reveals a universal interrelation between dynamics and thermodynamics and an unambiguous transition between liquidlike and gaslike states. This is seen in the master plot showing a collapse of the data representing the dependence of specific heat on key dynamical parameters in the system for many different paths on the phase diagram. As a result, the observed transition is path independent. We call it a "c" transition due to the c-shaped curve parametrizing the dependence of the specific heat on key dynamical parameters. The c transition has a fixed inversion point and provides a new structure to the phase diagram, operating deep in the supercritical state (up to, at least, 2000 times the critical pressure and 50 times the critical temperature). The data collapse and path independence as well as the existence of a special inversion point on the phase diagram are indicative of either of a sharp crossover or a new phase transition in the deeply supercritical state.

Pronounced structural crossover in water at supercritical pressures.

There have been ample studies of the many phases of H2O in both its solid and low pressure liquid states, and the transitions between them. Using molecular dynamics simulations we address the hitherto unexplored deeply supercritical pressures, where no qualitative transitions are thought to take place and where all properties are expected to vary smoothly. On the basis of these simulations we predict that water at supercritical pressures undergoes a structural crossover across the Frenkel line at pressures as high as 45 times the critical pressure. This provides a new insight into the water phase diagram and establishes a link between the structural and dynamical properties of supercritical water. Specifically, the crossover is demonstrated by a sharp and pronounced at low pressures, and smooth at high pressures, signified by changes in the pair distribution functions and local coordination which coincide with the dynamical transition (the loss of all oscillatory molecular motion) at the Frenkel line on the phase diagram.

Crossover of dynamical instability and chaos in the supercritical state.

We calculate the maximal Lyapunov exponent for a bulk system of 256 Lennard-Jones particles in constant energy molecular dynamics simulations deep into the supercritical state. We find that the maximal Lyapunov exponent undergoes a crossover and that this crossover coincides with the dynamical crossover at the Frenkel line from liquid physics. We explain this crossover in terms of two different contributions to dynamical instability: diffusion in the liquidlike state below the Frenkel line and collisions in the gaslike state above. These results provide insight into the phase-space dynamics far from the melting line and densities where rare-gas approximation are inapplicable.

Prostate cancer and its mimics at multiparametric prostate MRI.

One in six males will develop prostate cancer during their lifetime. Prostate cancer is the second leading cause of cancer death in American males, behind only lung cancer. Unfortunately, even though this disease is so common, clinical screening methods such as prostate-specific antigen test and transrectal ultrasound-guided prostate biopsy lack sensitivity and specificity in diagnosing prostate cancer. In recent years, multiparametric prostate MRI has emerged as a very important tool in the diagnosis of prostate carcinoma with a high accuracy. However, diagnostic difficulty is often encountered even with an experienced abdominal radiologist. That is mainly because many normal and abnormal entities can mimic prostate carcinoma at multiparametric MRI. Therefore, the purpose of this pictorial review is to discuss the usefulness of multiparametric prostate MRI in the diagnosis of prostate carcinoma, emphasizing the key MRI features that help to make a distinction of prostate carcinoma from its mimics.

Wound healing in cell studies and animal model experiments by Low Level Laser Therapy; were clinical studies justified? a systematic review.

Based on results of cell studies and animal experiments, clinical trials with Low Level Laser Therapy (LLLT) were performed, which finally did not demonstrate a beneficial effect on outcome of wound healing. The aim of this study was to investigate whether the evidence from cell studies and animal experiments with respect to wound healing was unequivocally in favour of LLLT, which would imply that these models might be adequate to predict treatment response in patients, or that the data of cell studies and animal experiments were inconclusive, which would mean that the clinical trials were based on insufficient evidence. We performed a systematic review of cell studies and animal experiment with LLLT on wound healing. Manuscripts were identified by searching Medline, Embase, and SPIE (the International Society for Optical Engineering). We assessed whether studies showed a beneficial effect of active treatment or not. The effect size was expressed in standardised mean difference [(SMD) the mean outcome measure of the treatment group minus the mean outcome measure of the control group, divided by the pooled standard deviation of these measurements]. In-depth analyses were performed on (1) studies in which inflicted wounds on animals were irradiated and evaluated; (2) studies with primary outcome measures on dimensions with direct reference to wound healing (ranging from acceleration of wound closure to epithelialisation, but excluding surrogate dimensions with regard to wound healing; in this case: tensile strength); (3) animal studies with 'true controls'; (4) studies in which animals functioned as their 'own controls' and (5) studies with the highest methodological quality score. The 36 included studies contained 49 outcome parameters of which 30 reported a positive effect of laser irradiation and 19 did not. Eleven studies presented exact data about the effect of active treatment and controls. The pooled effect size (SMD) over 22 outcome measures of these studies was - 1.05 (95% Cl: - 1.67 to - 0.43) in favour of LLLT. Methodological quality of the studies was poor. In-depth analysis of studies showed no significant pooled effect size in studies with highest methodological quality scores [0.06 (95% CI:- 0.42 to 0.53)]. Summarising the data of cell studies and animal experiments, reviewed in this manuscript, these studies failed to show unequivocal evidence to substantiate the decision for trials with LLLT in a large number of patients. In fact, there were no differences between the results of these experiments and clinical studies. Remarkably, we found that (almost from the introduction on) animal experiments and clinical studies that address the biological effects of LLLT on wound healing, ran simultaneously, rather than in sequence. We conclude that this type of phototherapy should not be considered a valuable (adjuvant) treatment for this selected, generally therapy-refractory condition in humans.

Angiographic evaluation of patients with unilateral massive perfusion defects in the lung scan.

Pulmonary embolism is an uncommon cause of a massive unilateral lung scan perfusion defect; other causes may mimic PE clinically. Angiography may, therefore, be essential for accurate diagnosis.

Selective low-dose streptokinase infusion in the treatment of acute transplant renal vein thrombosis.

A renal transplant recipient developed acute renal transplant vein thrombosis following surgery for a total hip replacement. As an alternative to standard surgical therapy, the patient was treated with selective intravenous low-dose infusion of streptokinase at doses of 5,000-20,000 units/h. The infusion was continued for 120 h with constant monitoring of PT, PTT, and fibrinogen levels. Therapy resulted in excellent preservation of renal function without complications. Low-dose selective infusion of streptokinase should be considered a potential alternative therapy for acute transplant renal vein thrombosis.

Lipoxygenase metabolism of arachidonic acid in brain.

When blood-free mouse brain slices were incubated with exogenous radiolabeled arachidonic acid, gas chromatography/mass spectrometry confirmed that the major radioactive lipoxygenase enzyme product of arachidonic acid was 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE), with lesser amounts of 5-hydroxy-5,6,8,11,14-eicosatetraenoic acid and 15-hydroxy-5,8,11,13-eicosatetraenoic acid. When 12-[2H]HETE was used to measure endogenous 12-HETE in brain tissue frozen with liquid nitrogen, the level of 12-HETE was 41 +/- 6 ng/g of wet weight tissue. This frozen tissue level was not due to the presence of blood. When brain slices were incubated in vitro for 20 min, the 12-HETE level increased to 964 +/- 35 ng/g of wet weight tissue. Elimination of residual intravascular blood before tissue incubation reduced the brain slice 12-HETE concentration by one-half.

Crystal retention by injured urothelium of the rat urinary bladder.

Injuries caused by hydrochloric acid or Triton X 100 application to the rat bladder urothelium, and the effects on calcium oxalate crystal retention, were examined by light and scanning electron microscopy. Damage due to either compound resulted in desquamation of urothelial cells. The crystals appeared to be retained by a fibrillar material, some of which was identified as fibrin. Heparin treatment of injured urothelium was found to prevent crystal retention.

Upright tomographic oral cholecystography.

Linear tomography performed with the patient in the upright position is a horizontal beam examination useful for further evaluation of the gallbladder during oral cholecystography in cases of superimposed densities and for confirmation of lesions attached to the wall of the gallbladder.

Intramural gastric diverticula: a report of three cases.

Intramural gastric diverticula are true diverticula, entirely contained within the wall of the stomach without deformity of the serosa. All of the 13 known reported cases are at the greater curvature of the distal antrum. This is true of our three cases as well. The unique location and characteristic change in shape with peristalsis distinguish them from pathological entities.

The effect of superoxide dismutase and catalase on metabolism of 3H-arachidonic acid by washed platelets.

Previous experiments have suggested that superoxide dismutase (SOD) and catalase (CAT) may inhibit prostaglandin synthesis. The purpose of this study was to determine if these free radical scavengers can alter the metabolism of free arachidonic acid (AA) by the cyclooxygenase and lipoxygenase enzyme systems in platelets. In control experiments washed platelets were incubated with 3H-AA for 5 minutes, extracted and the products separated by reverse phase high pressure liquid chromatography (HPLC). In normal intact platelets 13.5 +/- 0.6% of the radioactivity was found in TxB2, 16.3 +/- 1.4% in HHT, 61.3 +/- 1.1% in 12-HETE and 9.0 +/- 1.0% was unconverted AA. Pre-incubating the platelets for 1 minute with 10 micrograms/ml SOD or CAT or 10 micrograms/ml SOD plus 10 micrograms/ml CAT did not inhibit AA conversion or alter the percent product distribution. Similarly, SOD and CAT had no effect on AA metabolism in broken cells. However, as expected, pretreating platelets with indomethacin blocked TxB2 and HHT formation (P less than .0001). We conclude that SOD and CAT do not inhibit cyclooxygenase or lipoxygenase metabolism of free AA in platelets.

The effect of PGF2 alpha on in vivo cerebral arteriolar diameter in cats and rats.

We compared the effect of topical application of PGF2 alpha on cerebral arterioles in cats and rats equipped with an acutely implanted cranial window. Arterial diameter was measured using a microscope and image splitting device. PGF2 alpha in a concentration ranging from 10(-7) to 10(-5) M had no effect on large (greater than or equal to 100 microns) or small (less than 100 microns) cat pial arterioles, but induced a dose dependent constriction of rat pial arterioles with a maximum constriction to 76% of control diameter. Dilation of cat large cerebral arterioles by topically applied PGE2 was not affected by simultaneous application of PGF2 alpha and PGE2 induced dilation of small arterioles was decreased 3% by PGF2 alpha. While we and others have previously shown that both cat and rat brain can synthesize PGF2 alpha, it appears that PGF2 alpha is not likely to normally be a major modulator of cerebral arteriolar resistance in all species.

Some properties of mouse platelets.

Mouse platelets were aggregated by arachidonate, thrombin, collagen and ADP. In general they were, like rat platelets, more aggregative in heparinized PRP than in citrated (3.8%) PRP. Mouse platelets underwent the release reaction when aggregated by arachidonate, collagen and thrombin, but not when stimulated by ADP. The aggregation of the platelets to arachidonate was inhibited by cyclooxygenase inhibitors and by prostacyclin. Studies with tritiated arachidonate showed that mouse platelets possess the lipoxygenase and cyclooxygenase pathways found in other mammalian platelets and produce thromboxane and 12-HETE. The mouse provides a convenient model for the study of many conditions known to affect platelet aggregation. The similarity of mouse platelets to the platelets of other mammals together with the ability to study large numbers of animals at low cost, should encourage further use of mouse platelets.

Characterization of steroid binding specificity of the androgen receptor in human foreskin fibroblasts.

Our objective was to evaluate a convenient in vitro model for measuring steroid affinities to the human androgen receptor. The ability of unlabeled analogues of dihydrotestosterone (DHT) to compete with [3H]DHT for binding to the receptor in human fibroblasts was measured and expressed relative to DHT. The C-3 ketone group and the planar configuration of the A and B rings were critical for binding. Absence of the 10 beta-methyl group increased affinity of the androstane compounds for the receptor. The 17 beta-hydroxyl group was also essential for high affinity binding and addition of a 17 alpha-methyl group enhanced binding. Binding of steroids with a delta 4 double bond was consistently less than that of the 5 alpha-reduced steroids. This was true of both the androstene and estrene series. We conclude that human foreskin fibroblasts offer a useful model for in vitro studies characterizing the effects of steroid structural modifications on binding to the human androgen receptor.