Automatic monitoring of deposition conditions during rf sputtering of dielectric materials

Modern optics often require dielectric thin films of precisely controlled optical indices. One method of producing such films is by rf sputtering at extremely low deposition rates (～0·1 μh^?1). Thermal and plasma instabilities occur during the deposition process (often > 10 h duration) and the sputtering system therefore requires continuous monitoring to ensure appropriate corrective action.The objective of this paper is to examine the technology involved in developing supervision circuitry to monitor the parameters of a conventional commercially available rf sputtering system employed in the fabrication of high optical quality dielectric films for integrated-optics applications. The techniques used have overcome the difficulties of operating analogue circuitry in a high rf noise environment.A novel reflection-interferometer, enabling continuous monitoring of sputtered film thickness in a close spaced target-substrate system, was developed. The design has been shown to possess enhanced alignment tolerance, particularly for high refractive index films.     

Audit and its impact in the management of early prostatic cancer

An analysis was made of a prospective database of 614 men with newly diagnosed carcinoma of the prostate who presented between January 1978 and December 1990; 3-monthly updates were available on their clinical, haematological and biochemical parameters and 6-monthly updates on chest X-rays, bone scans and skeletal X-rays. It was found that 107 men (mean age 73.5 years) had early disease at presentation. Their management was based on regular surveillance and the treatment deferred until disease progression or development of symptoms. The audit of outcome measured various clinical events. Four patients (3.7%) developed local failure, 11 (10.3%) developed bone metastases, 3 (2.8%) died of cancer with a median survival of 6.3 years, and 34 (31.8%) died of intercurrent disease with a median survival of 2.6 years. The observed survival for 12 years of the whole group was similar to the expected survival for an age-matched population in Scotland. The standardised mortality ratio was 81 (95% confidence limits 57-112).     

Effects of muscarinic agents on cultured human trabecular meshwork cells

Intracellular calcium measurements were performed in cultured human trabecular meshwork cells preloaded with the cell permeant dye fura 2-AM. Fluctuations in calcium levels were then monitored with microscope-based ratio fluorometry. Carbachol increased intracellular calcium in a dose-dependent manner; as did oxotremorine-M, aceclidine, and pilocarpine. Carbachol's effect was blocked by the non-selective muscarinic antagonist atropine, as well as by muscarinic receptor subtype-selective antagonists such as pirenzepine (M1-selective), p-fHHSiD (M3-selective), and 4-DAMP (M1, M3 subtypes). Rank order of potencies for the antagonists' effects was atropine = 4-DAMP > p-fHHSiD > pirenzepine, a profile suggesting that the M3 receptor subtype is essential in the carbachol effect. Phospholipase C activity was estimated via measurement of total production of inositol phosphates in cultured human trabecular meshwork cells pre-exposed to 3H-myoinositol. In these cells, carbachol also stimulated phosphoinositide production in a dose-dependent manner, and an antagonist profile similar to that seen for calcium response was obtained when carbachol was used as the effector. The data indicate that muscarinic effects on cultured human trabecular meshwork calcium mobilization and phospholipase C activity are mediated by an M3-like receptor subtype. Therefore, the muscarinic M3 receptor may play a role in trabecular meshwork cell function(s).     

Gentle STEM: ADF imaging and EELS at low primary energies

Aberration correction of the scanning transmission electron microscope (STEM) has made it possible to reach probe sizes close to 1 Å at 60 keV, an operating energy that avoids direct knock-on damage in materials consisting of light atoms such as B, C, N and O. Although greatly reduced, some radiation damage is still present at this energy, and this limits the maximum usable electron dose. Elemental analysis by electron energy loss spectroscopy (EELS) is then usefully supplemented by annular dark field (ADF) imaging, for which the signal is larger. Because of its strong Z dependence, ADF allows the chemical identification of individual atoms, both heavy and light, and it can also record the atomic motion of individual heavy atoms in considerable detail. We illustrate these points by ADF images and EELS of nanotubes containing nanopods filled with single atoms of Er, and by ADF images of graphene with impurity atoms.     

Wear of ceramic-protected agricultural subsoilers

The high cost of wear to the farmer is generally recognized, and much research has been undertaken to improve the life of components used to work the soil. Owing to the limitations of more conventional materials and treatments, recent work has centred on using alumina ceramic to protect such components. This paper examines the performance of alumina in agricultural soils, using as an example an implement known as a subsoiler to which ceramic protection has been applied.     

Combinatorial materials research applied to the development of new surface coatings VII: an automated system for adhesion testing

An automated, high-throughput adhesion workflow that enables pseudobarnacle adhesion and coating/substrate adhesion to be measured on coating patches arranged in an array format on 4x8 in.(2) panels was developed. The adhesion workflow consists of the following process steps: (1) application of an adhesive to the coating array; (2) insertion of panels into a clamping device; (3) insertion of aluminum studs into the clamping device and onto coating surfaces, aligned with the adhesive; (4) curing of the adhesive; and (5) automated removal of the aluminum studs. Validation experiments comparing data generated using the automated, high-throughput workflow to data obtained using conventional, manual methods showed that the automated system allows for accurate ranking of relative coating adhesion performance.     

Morphology, ultrastructure, and implied function of ciliated sensory structures on the developmental stages of Merizocotyle icopae (Monogenea: Monocotylidae)

Experimental infections were used to track the fate of the dorsal sensilla of Merizocotyle icopae (Monogenea: Monocotylidae) from nasal tissue of the shovelnose ray, Rhinobatos typus (Rhinobatidae). Scanning and transmission electron microscopy revealed that 3 types of uniciliate dorsal sensilla exist at different times in the development of the monogenean. Type 1 sensilla have little or no invagination where the cilium exits the distal end of the dendrite and possess a ring of epidermis surrounding the cilium distal to the invagination. Type 2 sensilla have a deep invagination where the cilium exits the dendrite. Type 3 sensilla can be distinguished from the other types by the shape of the dendrite. The larvae have predominantly Type 1 dorsal sensilla, most of which are lost approximately 24 h after infection and a few Type 2 sensilla, which are retained. Additional Type 2 sensilla (termed Adult Type 2 sensilla), which are slightly different morphologically from the Type 2 sensilla of the larvae, form in later stages of development. Numerous Type 3 sensilla are unique to the dorsal surface of adults. Loss of all Type 1 sensilla upon attachment to the host, R. typus, suggests that these may be chemo- or mechanoreceptors responsible for host location by the swimming infective larvae. Type 2 sensilla appear to be important in the larvae, juveniles, and adults whereas the modality mediated by Type 3 is specific to adults.     

Mechanical stress induces release of ATP from Ehrlich ascites tumor cells

The supernatant from a suspension of Ehrlich cells exposed to centrifugation at 700xg for 45 s induced a transient increase in the intracellular concentration of free, cytosolic Ca2+, [Ca2+]i, as well as activation of an outwardly rectifying whole-cell current when added to a suspension of non-stimulated cells. These effects were inhibited by suramin, a non-specific P2 receptor antagonist, and mimicked by ATP. Reversed phase HPLC analysis revealed that the supernatant from Ehrlich cells exposed to centrifugation contained 2. 6+/-0.2 microM ATP, and that the mechanical stress-induced release of ATP was inhibited by glibenclamide and verapamil, non-specific inhibitors of the cystic fibrosis transmembrane conductance regulator and P-glycoprotein, respectively. After trypan blue staining, less than 0.5% of the cells were unable to extrude the dye. Addition of extracellular ATP induced a suramin-sensitive, transient, concentration-dependent increase in [Ca2+]i, activation of an outwardly rectifying whole-cell current and a hyperpolarization of the plasma membrane. The ATP-induced hyperpolarization of the plasma membrane was strongly inhibited in the presence of charybdotoxin (ChTX), an inhibitor of several Ca2+-activated K+ channels, suggesting that stimulation of P2 receptors in Ehrlich cells evokes a Ca2+-activated K+ current. The relative potencies of several nucleotides (ATP, UTP, ADP, 2-MeSATP, alpha,beta-MeATP, bzATP) in eliciting an increase in [Ca2+]i, as well as the effect of repetitive addition of nucleotides were investigated. The results lead us to conclude that mechanical stimulation of Ehrlich cells leads to release of ATP, which in turn stimulates both P2Y1 and P2Y2 receptors, resulting in Ca2+ influx as well as release and activation of an outwardly rectifying whole-cell current.