Peak effect at microwave frequencies in swift heavy ion irradiated YBa2Cu3O7-δ thin films

The vortex dynamics at microwave frequencies in YBa₂Cu₃O_7-δ (YBCO) films have been studied. We observe a peak in the microwave (4.88 and 9.55 GHz) surface resistance in some films in magnetic fields up to 0.8 T. This is associated with the ‘peak-effect’ phenomenon and reflects the order-disorder transformation of the flux line lattice near the transition temperature. Introduction of artificial pinning centers like columnar defects created as a result of irradiation with 200 MeV Ag ion (at a fluence of 4×10¹⁰ ions/cm²) leads to the suppression of the peak in films previously exhibiting ‘peak effect’.     

From superhydrophobic‐ to superhydrophilic‐patterned poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) architectures as a novel platform for biotechnological applications

The manufacture of three‐dimensional patterned electroactive poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) microstructures with tailored architecture, morphology, and wettability is presented. The patterned microstructures are fabricated using a simple, effective, low cost, and reproducible technique based on microfluidic technology. These novel structures can represent innovative platforms for advanced strategies in a wide range of biotechnological applications, including tissue engineering, drug delivery, microfluidic, and sensors and actuators devices. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1802–1810     

Analytical applications of membrane extraction in chromatography and electrophoresis

An overview of the analytical applications of membrane-based systems for sample enrichment in chromatography and capillary electrophoresis is presented. A brief introduction to the different types of membranes and the main forces related to the transport through them is also given.     

Comparative study of epithelial and fibroblastic cell lines as an alternative cytotoxicity test to the Draize method

Several methods are being used with considerable advantage as alternatives to the Draize test, although some technical difficulties still persist. This work compared the sensitivity of HeLa and NCTC L 929 cells to evaluate the cytotoxicity of shampoos used by adults and children (undiluted and diluted to 25, 5, 1, and 0.1%), and eye drops and their containers and surfactants (diluted to 30, 10, 1, and 0.1%). Nondiluted adult shampoos and their 25 and 5% dilutions were cytotoxic for both cell lines. When diluted to 1%, only one of the shampoos was noncytotoxic, whereas among those diluted to 0.1%, only one was cytotoxic. Children's shampoos were cytotoxic when not diluted or diluted to 25%. From those diluted to 5%, only one was noncytotoxic for both cell lines. The cytotoxic tests showed that the eye drops and their containers were noncytotoxic. Surfactants were cytotoxic when diluted to 30 and 10% and noncytotoxic when diluted to 1 and 0.1%. An excellent correlation (r = 0.95) was demonstrated between the sensitivity of the HeLa and NCTC L929 cells in the evaluation of cytotoxicity reactions.     

Synthesis of New Xanthones,I

Condensation of salicylic acid and C-methylphloroglucinol gave the already known 1,3-dihydroxy-2-methylxanthone ( 1 ) along with two new compounds: 1,3-dihydroxy-4-methylxanthone ( 2 ) and a second one tentatively presented as being 1,3-dihydroxy-2-methyl-4-(2-hydroxybenzoyl)xanthone ( 3 ). The UV., IR., NMR, and mass spectra for the two first compounds are reported and their structures discussed on the basis of δ-values for H(2), H(4), CH₃(4) and CH₃(2). The UV. and IR. spectra for the third compound are reported too.     

Retrieval of transverse relaxation time distribution from spin-echo data by recurrent neural network

Inversion of transverse relaxation time decay curve from spin-echo experiments was carried out using Hopfield neural network, to obtain the transverse relaxation time distribution. The performance of this approach was tested against simulated and experimental data. The initial guess, necessary for the integration procedure, was established as the analytical Laplace inversion. Together with errors in the simulated data, inversion was also carried out with errors in this initial guess. The probability density function, calculated by the neural network, is used in multiple sclerosis diagnostics.     

Magnetic nanoscale aggregates of cobalt and nickel in MgO single crystals

The magnetic properties of Co and Ni nanosized aggregates formed after implantation of nickel and cobalt ions in magnesium oxide single crystals were investigated. The influence of the implantation energy and annealing treatments was characterized. The particle size distribution was determined from the combined analysis of the magnetic moment dependence on both magnetic field and temperature, and used to determine the magnetic anisotropy constant of the aggregates. The results for nickel aggregates indicate the presence of an antiferromagnetic layer after the annealing treatments.     

Liver metastases from unknown primary site: demonstration on MR images

To demonstrate the MR imaging features of liver metastases in patients with the clinical and histologic diagnosis of tumors of unknown primary tumors, a retrospective 7-year study was performed that included a total of 14 consecutive patients (7 men and 7 women; age range, 39-82 years; mean age, 60.6 years) with liver metastases from unknown primary site who had undergone MR imaging. The following lesion features were evaluated: a) number, b) diameter, c) signal intensity on T1 and T(2)-weighted images, and d) pattern of enhancement on immediate, 45 s and 90 s post gadolinium images. Lesions were classified as hypovascular, hypervascular and nearly isovascular relative to liver parenchyma as shown on immediate post gadolinium images. Patients were separated into four major groups, related to the histologic diagnosis of the lesions: (I) poorly differentiated neoplasms; (II) well-differentiated and moderately differentiated adenocarcinoma; (III) squamous cell carcinoma; (IV) combined poorly differentiated carcinoma and poorly differentiated adenocarcinoma. MRI findings were correlated with histologic information obtained by chart review and confirmed by retrospective histopathology review. All patients had the histologic diagnosis of adenocarcinoma: 8 patients belonged to group II (1 patient with the subtype well-differentiated and 7 patients with the subtype moderately differentiated) and 6 patients to group IV. Eleven patients (79%) presented with multiple lesions distributed throughout both hepatic lobes; 3 patients exhibited solitary lesions. All solitary metastases possessed a diameter equal or larger than 5 cm. Patients with multiple metastases demonstrated a wide range of diameter, ranging from less than 1.5 cm to more than 5 cm. Regarding lesion vascularity, 4 of 13 of the patients had hypovascular metastases and 9 of 13 of the patients had hypervascular lesions. One patient demonstrated both types of lesions. Five of six patients with the histopathologic diagnosis of poorly differentiated adenocarcinoma demonstrated hypervascular metastases. Solitary metastases were most often hypovascular (2 of 3); however no correlation with the histologic subtype was possible. Liver metastases from unknown primary site are often multiple and often hypervascular. Poorly differentiated tumors are the most common histologic type. Metastases are not uncommonly hypovascular, and these are often solitary.