Mechanisms of atomic layer deposition on substrates with ultrahigh aspect ratios

Atomic layer deposition (ALD) appears to be uniquely suited for coating substrates with ultrahigh aspect ratios (> or similar 10(3)), including nanoporous solids. Here, we study the ALD of Cu and Cu3N on the inner surfaces of low-density nanoporous silica aerogel monoliths. Results show that Cu depth profiles in nanoporous monoliths are limited not only by Knudsen diffusion of heavier precursor molecules into the pores, as currently believed, but also by other processes such as the interaction of precursor and reaction product molecules with pore walls. Similar behavior has also been observed for Fe, Ru, and Pt ALD on aerogels. On the basis of these results, we discuss design rules for ALD precursors specifically geared for coating nanoporous solids.

New method for objectively assessing lameness in broiler chickens

A new method for assessing the severity of lameness in broiler chickens is described. The length of time that birds remained standing in shallow water was measured and the results were compared with the results of conventional gait scoring. There was a highly significant (P < 0.001) relationship between the birds' gait scores and their latency to lie down. Over 750 broilers aged between 32 and 45 days of age were tested in commercial houses and whereas nearly all the sound birds were able to stand for at least 15 minutes, the majority of lame birds lay down within five minutes.

Interaction of HIV-1 Tat with Puralpha in nuclei of human glial cells: characterization of RNA-mediated protein-protein binding

A complex between the Tat protein, encoded by human immunodeficiency virus type 1 (HIV-1), and the cellular protein, Puralpha, has been implicated in activation of the late promoter of JC virus (JCV) and in enhancement of JCV DNA replication. JCV is the causative agent of progressive multifocal leukoencephalopathy (PML), an acquired immunodeficiency syndrome (AIDS) opportunistic infection of the brain. Puralpha also binds the HIV-1 TAR RNA element and activates HIV-1 transcription, suggesting a role for RNA binding in the action of this protein. Using immunoelectron microscopy, we find that in human glial cells expressing both proteins, Tat and Puralpha are colocalized in extranucleolar chromatin structural elements. The colocalized Puralpha and Tat are nearly exclusively nuclear, although individual proteins can be seen in both nucleus and cytoplasm, suggesting a preferential tropism of the complex for the nucleus. Analysis of the interaction between purified proteins indicates that the Tat-Puralpha interaction is strongly enhanced by the presence of RNA. Tat amino acids from 37-48 are essential for Tat binding. Residues 49-72, including the TAR RNA-binding domain, are critical for binding to Puralpha, while Cys(22), in the Tat transactivation domain, is responsible for an important global effect. Puralpha repeat II domains are involved in the interaction, and a polypeptide based on one such sequence inhibits binding. After RNase treatment of Puralpha enhancement of Tat binding can be partially restored by addition of a single-stranded JCV DNA PUR element, to which Tat does not bind. The results indicate that the Tat-Puralpha interaction is direct, rather than through an RNA link, and that RNA binding configures Puralpha for optimal interaction with Tat.

Paleomagnetic Tests of Pacific Plate Reconstructions and Implications for Motion Between Hotspots

The plate-motion circuit through the South Pacific and Antarctica is shown to fail paleomagnetic tests of consistency. These failures imply that reconstructions of Pacific basin plates relative to surrounding plates inferred from this circuit are systematically in error and that estimates of motion between hotspots inferred from this circuit are probably too large. Therefore, the motions between hotspots remain poorly known and may be much smaller than previously estimated.

Global Tectonics and Space Geodesy

Much of the success of plate tectonics can be attributed to the near rigidity of tectonic plates and the availability of data that describe the rates and directions of motion across narrow plate boundaries \m=~\1 to 60 kilometers wide. Nonetheless, many plate boundaries in both continental and oceanic lithosphere are not narrow but are hundreds to thousands of kilometers wide. Wide plate boundary zones cover \m=~\15 percent of Earth's surface area. Space geodesy, which includes very long baseline radio interferometry, satellite laser ranging, and the global positioning system, is providing the accurate long-distance measurements needed to estimate the present motion across and within wide plate boundary zones. Space geodetic data show that plate velocities averaged over years are remarkably similar to velocities averaged over millions of years.

Ankle arthrodesis with an anterior tension plate

The incidence of complications associated with arthrodesis of the ankle has remained high, especially in wound complications and infections. A new method to achieve arthrodesis of the ankle that utilizes an anterior surgical approach and an anterior tension plate was assessed in 17 patients. This method transforms the potentially deforming force of the tendoachilles into a compressive and corrective force and facilitates realignment of the ankle in all planes. Also, dissection and subperiosteal elevation is minimized while soft tissue coverage of the hardware is maximized. Whereas the predominant preoperative diagnosis was posttraumatic degenerative joint disease, others included failed ankle arthroplasty, failed arthrodesis, and a fixed equinus deformity. A solid arthrodesis was achieved in 82% of the patients. Although complications occurred and two patients required reoperations, there were no problems with respect to wound healing or infection, which is a marked contrast to other series. This technique is recommended as a simple, safe, and effective method to achieve an arthrodesis of the ankle joint.

Nalbuphine: a supplement to isoflurane and enflurane anaesthesia

A retrospective study was carried out to review the intra-operative use of nalbuphine at the average dose of 1.5 mg/kg as a supplement to isoflurane and enflurane in balanced anaesthesia in 108 surgical patients. Intra-operative cardiovascular stability and the quality of emergence were examined. The amount of halogenated anaesthetic used was compared to the theoretical amount that would have been needed in the absence of nalbuphine. In 90% to 95% of patients, blood pressures remained within 20% of baseline for the duration of anaesthesia. At emergence, 80% of patients had no pain. Nalbuphine appeared to reduce halogenated anaesthetic requirements by approximately 50%. These promising results for the intraoperative use of nalbuphine need to be confirmed by controlled prospective studies.