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Abstract Background Cell transdifferentiation is characterized by loss of some phenotypes along with acquisition of new phenotypes in differentiated cells. The differentiated state of a given cell is not irreversible. It depends on the up- and downregulation exerted by specific molecules. Results We report here that HCCR-1, previously shown to play an oncogenic role in human cancers, induces epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET) in human and mouse, respectively. The stem cell factor receptor CD117/c-Kit was induced in this transdifferentiated (EMT) sarcoma tissues. This MET occurring in HCCR-1 transfected cells is reminiscent of the transdifferentiation process during nephrogenesis. Indeed, expression of HCCR-1 was observed during the embryonic development of the kidney. This suggests that HCCR-1 might be involved in the transdifferentiation process of cancer stem cell. Conclusions Therefore, we propose that HCCR-1 may be a regulatory factor that stimulates morphogenesis of epithelia or mesenchyme during neoplastic transformation.

Entropy production (EP) is a fundamental quantity useful for understanding irreversible process. In stochastic thermodynamics, EP is more evident in probability density functions of trajectories of a particle in the state space. Here, inspired by a previous result that complex networks can serve as state spaces, we consider a data packet transport problem on complex networks. EP is generated owing to the complexity of pathways as the packet travels back and forth between two nodes along the same pathway. The total EPs are exactly enumerated along all possible shortest paths between every pair of nodes, and the functional form of the EP distribution is proposed based on our numerical results. We confirm that the EP distribution satisfies the detailed and integral fluctuation theorems. Our results should be pedagogically helpful for understanding trajectory-dependent EP in stochastic processes and exploring nonequilibrium fluctuations associated with the entanglement of dividing and merging among the shortest pathways in complex networks. [ABSTRACT FROM AUTHOR]

Daniel Chonghan Hong was a professor of physics at Lehigh University and was the originator of the diffusing void model of granular flow. He died of cardiac arrest, after a period of hospitalization , on 6 July 2002 in Hershey, Pennsylvania.

Objectives/Hypothesis: Caudal septal deviation interrupts normal nasal breathing, due to the narrowing of the external valve area and nasal valve angle. In this study, we found a different approach for correction of caudal septal deviation with no associated deformity of the external nose. Study Design: Individual case-control study. Methods: The 39 patients completed questionnaires by interviews postoperatively for assessment of nasal obstruction. In addition, patients assessed the severity of their nasal symptoms (i.e., mouth breathing, mouth dryness, hyposmia, rhinorrhea, epistaxis, snoring, postnasal drip, and headache) preoperatively and postoperatively using a visual analog scale (VAS). Improvement in the treatment of nasal obstruction using a VAS and a questionnaire for subjective satisfaction were evaluated 3 months after septoplasty. To evaluate outcomes objectively, endoscopic photographs of the nasal cavity and acoustic rhinometry before and after surgery were evaluated. For comparison between preoperative and postoperative status, the Wilcoxon signed ranks test was used. Results: Patients reported a significant decrease in the VAS severity of all nasal symptoms. The minimal cross-sectional area (MCA1) of the convex side after vascular constriction using acoustic rhinometry showed significant widening. Patients were divided into a turbinoplasty group and a nonturbinoplasty group, and the turbinoplasty group showed a significant increase in both the convex side and concave side in MCA1 and in the convex side in the anterior portion of the inferior turbinate. Conclusions: Endonasal septoplasty using bony batten grafting for caudal septal deviation resulted in an improvement of nasal obstruction symptoms and acoustic rhinometry components. [ABSTRACT FROM AUTHOR]

Background: Cell transdifferentiation is characterized by loss of some phenotypes along with acquisition of new phenotypes in differentiated cells. The differentiated state of a given cell is not irreversible. It depends on the up- and downregulation exerted by specific molecules. Results: We report here that HCCR-1, previously shown to play an oncogenic role in human cancers, induces epithelialto- mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET) in human and mouse, respectively. The stem cell factor receptor CD117/c-Kit was induced in this transdifferentiated (EMT) sarcoma tissues. This MET occurring in HCCR-1 transfected cells is reminiscent of the transdifferentiation process during nephrogenesis. Indeed, expression of HCCR-1 was observed during the embryonic development of the kidney. This suggests that HCCR-1 might be involved in the transdifferentiation process of cancer stem cell. Conclusions: Therefore, we propose that HCCR-1 may be a regulatory factor that stimulates morphogenesis of epithelia or mesenchyme during neoplastic transformation. [ABSTRACT FROM AUTHOR]

We have designed and constructed a spectroscopic interferometer, and test run its operation with a pulsed discharge plasma. The plasma is produced by capacitor discharge across a gap filled with neutral argon at selected pressures. Ablation of iron from the cathode adds to argon to form equilibrium plasma of an argon-iron mixture. The ablative mass addition is measured and incorporated into the system of Saha equations. The calculated plasma energy is compared to independently measured total energy injected into the plasma to determine the peak plasma temperature. The measured coherence length of an argon emission line shows a dependence on the direction of the line of sight and a scaling with collision time within the plasma. [ABSTRACT FROM AUTHOR]

A single laser pulse is used to produce weakly nonideal plasma from a metallic aluminum target immersed in a dense neutral gas. The attendant increase in plasma density due to neutral gas confinement precipitates interfacial instability when the gas density exceeds a threshold value. This is accompanied by large fluctuations in the total attenuation of the laser beam by the laser-produced plasma plume. We have developed a new diagnostic method utilizing two mutually orthogonal side-view streak photographs of plasma continuum luminosity at a fixed distance from the target surface. The lack of axial symmetry is overcome by using a front-view luminosity image of the plasma at time zero as a two-dimensional weighting factor. The resulting profile at one time is used as the weighting factor for the next time segment. The time-resolved reconstructed plasma profiles clearly exhibit the near-threshold behavior of Rayleigh–Taylor type instability. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We have developed a novel diagnostic technique for weakly nonideal laser-produced plasma (LPP) plumes, based entirely on the continuum, and present the result for aluminum plasma. Due to significant self-absorption, the analysis is carried out in close coupling with plasma equilibrium calculations. We first invoke scaling relations linking the time- and position-resolved specific continuum intensity I, integrated over the spectral range of a streak camera, to the local temperature T and pressure p: T=S[sub T]I[sup α] and p=S[sub p]I[sup α+β]. Inversion of the two-dimensional luminosity profile into the specific continuum intensity profile (three-dimensional) is carried out self-consistently, subject to the 16 independent measurements: target mass loss, energy deposited into the LPP plume and laser beam attenuation at fundamental and its harmonic frequencies, all at four different laser energies. An agreement to within 6.1% of the measurements overall has been achieved with α=0.45±0.03, β=1.0±0.03, S[sub T]=0.190±0.003 and S[sub p]=340±5. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

X-pinch plasmas have been actively studied in the recent years. Numerical simulation of the ramp-up of metallic vapor emissions from wire specimens shows that under impulsive Ohmic heating the wire core invariably reaches a supercritical state before explosion. The heating rate depends sensitively on the local wire resistance, leading to highly variable vapor emission flux along the wire. To examine the vapor emission process, we have visualized nickel wire explosions by means of shock formation in air. In a single explosion as captured by shadowgraphy, there usually appear several shocks with spherical or cylindrical wave front originating from different parts of the wire. Growth of various shock fronts in time is well characterized by a power-law scaling in one form or another. Continuum emission spectra are obtained and calibrated to measure temperature near the explosion threshold. Shock front structures and vapor plume temperature are examined. [ABSTRACT FROM AUTHOR]

Dense atom vapors are created as remnants of a three-dimensional (3D) laser-produced plasma (LPP) plume driven from a solid aluminum target by a gigawatt-class Nd:glass laser pulse. Formation of nanoclusters as the terminal state of aluminum vapors has been investigated. By plasma structure diagnosis, we have fully characterized the LPP plume in 3D as a function of time and from its evolution modeled its cooling to the critical point in more than 110 000 vapor cells. Clustering of atoms is calculated by numerical simulation of interparticle collisions. When the cluster size histogram is rescaled relative to the maximum population and the maximal radius, the rescaled histograms all collapse into a single functional form regardless of the time or the initial atom vapor density. The cluster size distribution for the entire plasma plume is obtained by summing over all plasma cells. Independently, the clusters are captured onto electron microscope grids and size analyzed by means of transmission electron microscopy. The computed result is in excellent agreement with the measured histograms of clusters by size. [ABSTRACT FROM AUTHOR]

A method is developed for structure reconstruction of an arbitrary plasma from two luminosity streaks and a front-view snapshot as a weighting function (WF). Two scaling relations link the pressure and temperature to the local specific emission intensity. A trial plasma structure is proposed in terms of specific intensity, and the luminosity streaks are calculated according to the Saha equilibrium. Plasma absorption is included. Error signals between the calculated and measured luminosity are allocated according to the WF to find corrections to local specific intensities. Minimization of the errors completes the reconstruction at a given time, which in turn updates the WF for the next time step. Summing over the full plasma over time facilitates calculation of the total plasma mass, energy and beam attenuation through the plasma. When agreement with their measured counterparts is maximized, the scaling relations are calibrated. [ABSTRACT FROM AUTHOR]

Pays tribute to James Alan McLennan Jr., an emeritus professor of physics at Lehigh University, who died on November 18, 2002.

Background: Cell transdifferentiation is characterized by loss of some phenotypes along with acquisition of new phenotypes in differentiated cells. The differentiated state of a given cell is not irreversible. It depends on the up- and downregulation exerted by specific molecules., Results: We report here that HCCR-1, previously shown to play an oncogenic role in human cancers, induces epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET) in human and mouse, respectively. The stem cell factor receptor CD117/c-Kit was induced in this transdifferentiated (EMT) sarcoma tissues. This MET occurring in HCCR-1 transfected cells is reminiscent of the transdifferentiation process during nephrogenesis. Indeed, expression of HCCR-1 was observed during the embryonic development of the kidney. This suggests that HCCR-1 might be involved in the transdifferentiation process of cancer stem cell., Conclusions: Therefore, we propose that HCCR-1 may be a regulatory factor that stimulates morphogenesis of epithelia or mesenchyme during neoplastic transformation.

Currently, most carotid artery pathologic abnormalities resulting in pseudoaneurysm formation or stenosis are repaired by surgical intervention. Because surgical intervention requires proximal and distal control of the artery, pseudoaneurysms near the skull base may be very difficult to repair and pose greater risk to the patient. As a result, endovascular techniques have evolved in an effort to reduce morbidity associated with surgical techniques. Parent vessel occlusion and coil placement are the most frequently used endovascular techniques for carotid artery repair of pseudoaneurysms. Intimal hyperplasia is generally treated with balloon angioplasty, often in conjunction with uncovered stent placement. Parent vessel occlusion may be impractical if the patient is unable to tolerate occlusion of that artery. We report our experience in treating three patients with carotid artery stent grafts.

Background and Purpose: Clinical cerebral-fat embolism shows both reversible and irreversible changes. We used MR imaging to investigate the reversibility of embolized lesions induced with a fat-emulsion technique and to evaluate the histologic findings., Methods: A fat emulsion was made with 0.05 mL of triolein and 20 mL of normal saline and vigorous to-and-fro movement through a three-way stopcock. In 50 cats, the internal carotid artery was infused with the fat emulsion. Cats were divided into six groups on the basis of time delay after embolization: 1 hour; 1 and 4 days; and 1, 2, and 3 weeks. MR imaging and histologic examination were performed at these times., Results: Embolized lesions were hyperintense on T2-weighted images, isointense or mildly hyperintense on diffusion-weighted images, isointense on apparent diffusion coefficient maps, and enhancing on gadolinium-enhanced T1-weighted images at 1 hour. These MR imaging findings were less evident at day 1 and reverted to normal after day 4 (isointense on all images). Electron microscopy showed minimal findings in the cortical lesion in groups 1 and 2 (group 1 at 1 hour and group 2 at 1 hour and 1 day). Light microscopic findings revealed evidence of necrosis-small focal gliosis and demyelination in the periventricular white matter-in only one cat. The number of intravascular fat globules was not significantly different between groups, as visualized by oil red O staining., Conclusion: Cerebral-fat embolism induced by a triolein emulsion revealed reversible MR findings and minimal histologic findings.