Entropy production and fluctuation theorems on complex networks.

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.

Transdifferentiation-inducing HCCR-1 oncogene.

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.

Use of covered stent grafts in the extracranial carotid artery: report of three patients with follow-up between 8 and 42 months.

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.

Reversible MR changes in the cat brain after cerebral fat embolism induced by triolein emulsion.

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.

How to resolve the caudal septal deviation? Clinical outcomes after septoplasty with bony batten grafting.

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.

Combined analysis of AFP and HCCR-1 as an useful serological marker for small hepatocellular carcinoma: a prospective cohort study.

Hepatocellular carcinoma (HCC) is one of the most frequent malignant tumors in the world. The only serological marker widely used for the diagnosis of HCC is alpha-fetoprotein (AFP). Despite that AFP is widely used for the diagnosis of HCC, it has a limit as a serological marker due to its low sensitivity and specificity. The human cervical cancer proto-oncogene 1 (HCCR-1) was previously reported as a new biomarker for HCC. To further evaluate the HCCR-1 as a biomarker for HCC, we conducted the prospective cohort study. We evaluated the significance of simultaneous measurement of 2 tumor markers in the diagnosis of HCC in China, Japan and Korea. Two markers for HCC, AFP and HCCR-1, were measured in the sera obtained from 1,338 patients at the time of initial diagnosis of HCC. Of the 1338 HCC patients, 616 (46%) and 686 (51.3%) were sero-positive for AFP and HCCR-1, respectively. The positive rate for HCC was increased up to 74.1% in combined use of AFP and HCCR-1. Many cases (54%) for AFP-negative HCC were positive for HCCR-1 and vice versa. More importantly, the diagnostic rate for small HCC (< 2 cm) was significantly improved in the combined analysis of AFP and HCCR-1 to 56.9% although it was only 40.1% and 23.4% in the single analysis of HCCR-1 and AFP, respectively. Our result suggests that the HCCR-1 could be an useful biomarker for HCC while the diagnostic rate could be significantly improved in the combined use of HCCR-1 and AFP.

Dynamics of vapor emissions at wire explosion threshold.

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.

Spectroscopic interferometer for coherence length spectroscopy of pulsed discharge plasma.

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.

Candidate tumor suppressor, HCCS-1, is downregulated in human cancers and induces apoptosis in cervical cancer.

To identify the genes involved in cervical carcinogenesis, we applied the mRNA differential display method and identified a candidate tumor suppressor gene, HCCS-1, which was present in normal cervical tissue but absent in cervical cancer, metastatic lymph node and CUMC-6 cervical cancer cell line. HCCS-1 transcripts were expressed in many normal tissues including leukocyte, lung, spleen, liver, heart and uterine cervix. Its expression was absent in 8 human cancer cell lines. HCCS-1-transfected HeLa cells exhibited growth inhibition by about 50%. This inhibitory effect of HCCS-1 on cervical cancer cells was associated with apoptotic process including DNA fragmentation. HCCS-1-transfected HeLa cells were shown to release cytochrome c from mitochondria, which activates caspase-9 and -3 and finally results in cleavage of poly(ADP-ribose) polymerase. Apoptosis formation was detected by propidium-iodide/annexin V. HCCS-1-transfected HeLa cells were more sensitive to adriamycin or UVC ray triggered apoptosis. These results suggest that HCCS-1 is downregulated in multiple human tumor types and may serve as a candidate tumor suppressor gene through apoptotic pathway against human cervical cancer.