Serum hepatitis B markers in blood donors in Venezuela. What do they mean?

Adenocarcinomas metastatic to brain from lung or colon may pose differentiation difficulties. Ultrastructurally, both may have brush borders with rootlets. This study examines the ultrastructural morphology and immunohistochemical expression of villin (associated with rootlets), cytokeratin 7 (present in lung adenocarcinomas), and cytokeratin 20 (present in colon adenocarcinomas) in 19 formalin-fixed sequential surgical biopsies of lung adenocarcinomas metastatic to brain as compared to 13 colonic adenocarcinoma metastases. Of lung tumor metastases, mucinous differentiation with rootlets was most common [6/19(32%)]. All colon tumor metastases were cytokeratin 7(-), 20(+), and profusely villin(+). Well-formed rootlets were seen. All lung metastases were cytokeratin 7(+) and 20(-). 5/6(83%) lung metastases with rootlets were focally villin(+). 12/13(95%) without rootlets were villin(-). Rootlets are extremely common in lung adenocarcinoma metastatic to brain. Villin immunoreactivity closely correlates with rootlets. Its distribution is a useful adjunct to cytokeratin 7 and 20 in differentiation of lung versus colon adenocarcinomas metastatic to the brain.     

Electronic, thermal and mechanical properties of carbon nanotubes

A review of the electronic, thermal and mechanical properties of nanotubes is presented, with particular reference to properties that differ from those of the bulk counterparts and to potential applications that might result from the special structure and properties of nanotubes. Both experimental and theoretical aspects of these topics are reviewed.     

Differences in heat tolerance between preimplantation embryos from Brahman, Romosinuano, and Angus breeds

Exposure to 41 degrees C reduces development of embryos of heat-sensitive breeds (Holstein and Angus) more than for embryos of the heat-tolerant Brahman breed. Here it was tested whether embryonic resistance to heat shock occurs for a thermotolerant breed of different genetic origin than the Brahman. In particular, the thermal sensitivity of in vitro produced embryos of the Romosinuano, a Bos taurus, Criollo-derived breed, was compared to that for in vitro produced Brahman and Angus embryos. At d 4 after insemination, embryos > or = 8 cells were randomly assigned to control (38.5 degrees C) or heat shock (41 degrees C for 6 h) treatments. Heat shock reduced the proportion of embryos that developed to the blastocyst stage on d 8 after insemination. At 38.5 degrees C, there were no significant differences in development between breeds. Among embryos exposed to 41 degrees C, however, development was lower for Angus embryos than for Brahman and Romosinuano embryos. Furthermore, an Angus vs. (Brahman + Romosinuano) x temperature interaction occurred because heat shock reduced development more in Angus (30.3 +/- 4.6% at 38.5 degrees C vs. 4.9 +/- 4.6% at 41 degrees C) than in Brahman (25.1 +/- 4.6% vs. 13.6 +/- 4.6%) and Romosinuano (28.3 +/- 4.1% vs. 17.5 +/- 4.1%). Results demonstrate that embryos from Brahman and Romosinuano breeds are more resistant to elevated temperature than embryos from Angus. Thus, the process of adaptation of Brahman and Romosinuano breeds to hot environments resulted in both cases in selection of genes controlling thermotolerance at the cellular level.     

Evaluation of vapor recovery systems efficiency and personal exposure in service stations in Mexico City

Results of a field study on the efficiency of vapor recovery systems currently used in gasoline service stations in Mexico City are presented. Nine gasoline stations were studied, representing the several technologies available in Mexico City. The test was applied to a fixed vehicular fleet of approximately 10 private and public service vehicles. Each one of the gasoline service stations tested reported efficiencies above 80% in the recovery of vapor losses from gasoline which is the minimum permissible value by Mexican regulations. Implications to the emissions inventory are discussed. A second goal of this study was to measure the potential exposure of service attendants to three important components of gasoline: benzene; toluene; and xylenes. The influence of spatial location of personnel within the service station was also evaluated by measuring levels of the three compounds both at the refueling area and in the service station office. Results are discussed and compared to a previous study.     

Use of a microchip device coupled with mass spectrometry for ligand screening of a multi-protein target

Nanoflow electrospray mass spectrometry has been applied previously to investigate noncovalent protein-protein and protein-ligand interactions. Here we evaluate a commercial microchip device for this application. We show that the microchip can be used to obtain mass spectra of the noncovalent tetramer transthyretin. The device showed a 10-fold increase in signal stability compared with a nanoflow capillary and a high level of nozzle-to-nozzle reproducibility. Binding of the natural ligand thyroxine was clearly observed, and a range of small molecules proposed as inhibitors of transthyretin amyloidosis were shown to be effective in stabilizing the tetramer. We propose that measuring the ability of small molecules to stabilize protein complexes using this automated microchip technology will enable high-throughput screening of multi-protein complexes by mass spectrometry.     

The Spanish National Dose Registry and Spanish radiation passbooks

The Spanish National Dose Registry (BDN) is the Nuclear Safety Council's (CSN) national database of occupational exposure to radiation. Each month BDN receives records of individual external doses from approved dosimetry services. The dose records include information regarding the occupational activities of exposed workers. The dose information and the statistical analysis prepared by the BDN are a useful tool for effective operational protection of occupationally exposed workers and a support for the CSN in the development and application of the ALARA principle. The Spanish radiation passbook was introduced in 1990 and since then CSN, as regulatory authority, has required that all outside workers entering controlled areas should have radiation passbooks. Nowadays, CSN has implemented improvements in the Spanish radiation passbooks, taking into account previous experience and Directive 96/29/EURATOM.     

On the effect of calibration in classifier combination

A general approach to classifier combination considers each model as a probabilistic classifier which outputs a class membership posterior probability. In this general scenario, it is not only the quality and diversity of the models which are relevant, but the level of calibration of their estimated probabilities as well. In this paper, we study the role of calibration before and after classifier combination, focusing on evaluation measures such as MSE and AUC, which better account for good probability estimation than other evaluation measures. We present a series of findings that allow us to recommend several layouts for the use of calibration in classifier combination. We also empirically analyse a new non-monotonic calibration method that obtains better results for classifier combination than other monotonic calibration methods.     

Winter and spring surface velocity fields in the Cape Blanc region as deduced with the maximum cross-correlation technique

The ocean surface velocity field in the Cape Blanc region, off Northwest Africa, is investigated with the maximum cross-correlation (MCC) method applied to channel-4 Advanced Very High Resolution Radiometer satellite images. An initial sensitivity analysis allows us to select the four parameters that provide maximum area coverage and the best velocity resolution, while limiting the standard deviation for each velocity component within reasonable values. These are (m, n, MV, CT)?=?(22, 32, 50, 0.6), where m and n are the number of pixels of the search window (SW) and reference window (RW), respectively, MV is the maximum possible velocity (in cm s^?1), and CT is a correlation threshold for a feature to be tracked. A total of 489 images, for years 2005 and 2006, are analysed, and 106 velocity maps are generated with good coverage of the coastal transition zone (CTZ), most of them for the winter (34) and spring (59) seasons. We remove spurious data using the method's own filters (MV, CT, and a neighbour-vector comparison), requesting the velocity components to have Gaussian distributions and smoothing the resulting velocity fields with a median-vector filter. The instantaneous velocity maps illustrate the response of the alongshore coastal jet north of Cape Blanc (and its extension along the Cape Verde frontal region) to wind forcing, as well as the presence of numerous mesoscalar features (100–300 km wide) superposed on a westward offshore transport south of Cape Blanc. We also produce mean and standard deviation winter and spring velocity maps, which are compared with the corresponding mean sea surface temperature fields. The along-shore and offshore flow is better defined and is more intense in spring than in winter, in concordance with cross-slope sharper temperature gradients during this season, and brings about a cooling of the whole region. We identify five different ubiquitous currents: a southwestward jet north of Cape Blanc, a northwestward jet off Banc d'Argin, an offshore convergent jet, a spring jet-like feature at 18° N, and a southward flow in the southwestern CTZ.     

Nonstationary discrete-time deterministic and stochastic control systems with infinite horizon

This article is about nonstationary nonlinear discrete-time deterministic and stochastic control systems with Borel state and control spaces, possibly noncompact control constraint sets, and unbounded costs. The control problem is to minimise an infinite-horizon total cost performance index. Using dynamic programming arguments we show that, under suitable assumptions, the optimal cost functions satisfy optimality equations, which in turn give a procedure to find optimal control policies.