Entropy production and irreversibility of dissipative trajectories in electric circuits.

We experimentally examine the equivalence between the entropy production evaluated from irreversibility of trajectories and the physical dissipation in dissipative processes via electric resistor-capacitor (RC) circuits. The examinations are performed for two nonequilibrium steady states that are driven by an injected current and temperature difference, respectively. Such an equivalence demonstrates a parameter-free method to evaluate the entropy production of a system. The effects of configurational and temporal resolutions are also studied.

Electrical autonomous Brownian gyrator.

We study experimentally and theoretically the steady-state dynamics of a simple stochastic electronic system featuring two resistor-capacitor circuits coupled by a third capacitor. The resistors are subject to thermal noises at real temperatures. The voltage fluctuation across each resistor can be compared to a one-dimensional Brownian motion. However, the collective dynamical behavior, when the resistors are subject to distinct thermal baths, is identical to that of a Brownian gyrator, as first proposed by Filliger and Reimann [Phys. Rev. Lett. 99, 230602 (2007)PRLTAO0031-900710.1103/PhysRevLett.99.230602]. The average gyrating dynamics is originated from the absence of detailed balance due to unequal thermal baths. We look into the details of this stochastic gyrating dynamics, its dependences on the temperature difference and coupling strength, and the mechanism of heat transfer through this simple electronic circuit. Our work affirms the general principle and the possibility of a Brownian ratchet working near room temperature scale.

Epidermal growth factor-induced ANGPTL4 enhances anoikis resistance and tumour metastasis in head and neck squamous cell carcinoma.

Epidermal growth factor (EGF) is important for cancer cell proliferation, angiogenesis and metastasis in many types of cancer. However, the mechanisms involved in EGF-induced head and neck squamous cell carcinoma (HNSCC) metastasis remain largely unknown. In this study, we reveal that angiopoietin-like 4 (ANGPTL4) plays an important role in the regulation of EGF-induced cancer metastasis. We showed that EGF-induced ANGPTL4 expression promoted anoikis resistance and cancer cell migration and invasion in HNSCC. In addition, depletion of ANGPTL4 inhibited EGF-induced cancer cell invasion. Autocrine production of EGF-induced ANGPTL4 regulated the expression of matrix metalloproteinases (MMPs). The induction of MMP-1 gene expression by ANGPTL4-activated integrin ß1 signalling occurred through the AP-1 binding site in the MMP-1 gene promoter. Furthermore, down-regulation of MMP-1 impeded EGF- and recombinant ANGPTL4-enhanced HNSCC cell migration and invasion. Depletion of ANGPTL4 significantly blocked EGF-primed extravasation and metastatic seeding of tumour cells and MMP-1 expression in lungs. However, no effect of ANGPTL4 on tumour growth was observed. These results suggest that EGF-induced expression and autocrine production of ANGPTL4 enhances HNSCC metastasis via the up-regulation of MMP-1 expression. Inhibition of ANGPTL4 expression may be a potential strategy for the treatment of EGFR-mediated HNSCC metastasis.

Introduction of an AmpR-L2 intergenic segment attenuates the induced beta-lactamase activity of Stenotrophomonas maltophilia.

Expression of the L1 and L2 beta-lactamase genes is generally regulated by a LysR type regulator of the AmpR in Stenotrophomonas maltophilia. The ampR gene is located immediately upstream of L2 and is transcribed divergently, forming an ampR-L2 module. The ampR-L2 modules of 16 S. maltophilia isolates were analyzed, revealing that the ampR-L2 intergenic (IG) regions show a significant genetic diversity, whereas AmpR proteins are highly conserved. The induction potential of the different AmpR toward the different ampR-L2 IG regions was evaluated by introducing the various IG-xylE transcriptional fusion constructs into a wild S. maltophilia strain. The induction levels achieved in the various AmpR-IG pairs display quantitative differences; meanwhile, the host beta-lactamase activity, in some cases, is attenuated by the introduced IG segment. Similar beta-lactamase attenuation phenomenon was observed in Enterobacter cloacae with an ampR-L2 IG segment of S. maltophilia. A concept of oligonucleotides attenuator for the development of an antimicrobial agent is proposed.

Coronary artery air embolism: a potentially fatal complication of CT-guided percutaneous lung biopsy.

CT-guided transthoracic lung biopsy is becoming a widely accepted procedure for the diagnosis of pulmonary lesions. The rate of severe complications following such a procedure has been reported. Of these complications, air embolism is the most likely to be fatal. We report a case of right coronary air embolism resulting in myocardial infarction after a CT-guided percutaneous needle biopsy of the lung. The patient died from underlying malignant disease 4 months later.

Modified nitrocefin-EDTA method to differentially quantify the induced L1 and L2 beta-lactamases in Stenotrophomonas maltophilia.

AIM: To estimate the ethylene diamine tetraacetic acid (EDTA) concentration at which the L1 enzyme activity in the cell extracts of Stenotrophomonas maltophilia can be mostly inhibited. METHODS AND RESULTS: The effective inhibition concentration of EDTA against the L1 enzyme in the cell extracts was firstly evaluated by using the L2 isogenic mutant of S. maltophilia KJ, KJDeltaL2, as the assayed strain. Approximately 92% L1 activity was inhibited by 10 mmol l(-1) EDTA, which is 100-fold higher than that from previously reported protocols (0.1 mmol l(-1)). Three phylogenetic clusters of L1 proteins were revealed from 11 clinical S. maltophilia isolates, with a L1 protein divergence of 0-11%. The EDTA concentration required to inhibit the L1 enzymes of different phylogenetic clusters was estimated to be 10 mmol l(-1). conclusion: The previous nitrocefin-EDTA protocol for differentially quantifying the L1 and L2 activity in the cell extracts has been modified by raising the added EDTA concentration to 10 mmol l(-1). SIGNIFICANCE AND IMPACT OF THE STUDY: A rapid and accurate method for determination of L1 and L2 activity will provide a convenient tool for enzyme characterization and induction mechanism study of S. maltophilia.

Synchronous ipsilateral renal cell and transitional cell carcinoma.

The coexistence of multiple and synchronous primary neoplasms in the genitourinary system has only rarely been described in the literature. We present the case of a 78-year-old man with haematuria as the initial presentation, finally proven to be transitional cell carcinoma (TCC) combined with renal cell carcinoma (RCC). Intravenous urography (IVU), CT and arterial angiography studies revealed a space-occupying nodule at the right upper renal pelvicalyces showing mild enhancement with contrast medium. Another strong contrast medium enhancing exophytic tumour was found at the lower pole of kidney; there were hypodense foci and calcified components in this lesion. A right nephroureterectomy was performed. Pathological diagnosis was a papillary TCC and a clear cell type RCC. This is a rare case of combined renal malignancies diagnosed by imaging.

MR findings of penile lymphoma.

Penile lymphoma is extremely rare and secondary involvement of the penis by lymphoma may be due to retrograde spread or to direct extension from neighbouring organ. The appearance of penile lymphoma varies and can be mistaken for other soft tissue tumours. We report on a case with malignant lymphoma of the penis. MRI findings revealed soft-tissue mass of homogeneous isointensity around the middle to distal part of penis on T(1) weighted imaging and T(2) weighted imaging. It was well encapsulated, minimally enhanced and distinct from corpus cavernosum and corpus spongiosum.

Nd-YAG Laser Treatment for Tracheobronchial Obstruction.

The Nd-YAG laser has good tissue penetration and coagulation effects thus has become an important weapon for photoresection of tracheobronchial obstructive lesions since 1980.Treatment of benign lesions including benign tumors and scar tissues using the Nd-YAG laser has good results. In the treatment of malignant tumors however, it has a lower effectivity rate when compared to benign lesions. From July 1984 to September 1995, a total of 65 patients were treated with Nd-YAG laser for tracheobronchial obstruction. There were 32 (49%) malignant tumors and 33 (51%) benign lesions. 116 resections were performed in 48 patients using the non-contact Nd-YAG laser (MBB, Medilas 2) before 1992. Thereafter, another 41 resections were performed in 17 cases using contact Nd-YAG laser (SLT, CL-X). The overall effectivity rate was 60%. The effectivity rate for benign lesions was 81.3% and 39.4% for malignant tumor. The effectivity rate between non-contact and contact Nd-YAG laser was not significantly different.

Direct measurement of the effective refractive indices of GaAs/AIGaAs slab waveguides: a new technique.

A new method is presented for accurately and nondestructively measuring the effective refractive indices of GaAs slab waveguides. The experimental setup is extremely simple. This method is particularly applicable for buried waveguides and high refractive index waveguides that cannot be measured by prism couplers. It is also suitable for glass and LiNbO(3) waveguides.