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Recovery and the postoperative period are times of significant physiological change, and, as with induction, the risks of complications and the need for rapid responses are at their greatest. The importance of controlled management and monitoring is discussed in this article. Airway control and breathing remain the most important aspects, and these are principally affected by residual muscular blockade, changing inhalational gas mixtures and returning reflex and conscious activity. The issues surrounding the assessment and appropriate management of muscular block, and the importance of maintaining oxygenation and normocapnia are emphasized. The various groups of sedating agents and the difficulties in their reversal are reviewed. The recovery period on the general ward is also examined, with particular emphasis on the provision and value of oxygenation, fluid management and analgesia.

Background Very late antigen (VLA-4) antagonists have been proposed as potential therapies for diseases in which cell recruitment and accumulation are causative. Asthma, which is characterized by airway inflammation involving the accumulation of eosinophils and mononuclear cells, is one such disease. Objective We sought to assess the effect of IVL745, a VLA-4 antagonist, on the early and late asthmatic response (LAR) and on markers of airway inflammation after allergen inhalation. Methods The study was of a placebo-controlled, double-blind, randomized, 2-way crossover design. Sixteen subjects with mild-to-moderate asthma controlled with short-acting β 2 -agonists only and with a LAR to inhaled allergen participated in the study. At one treatment period they took 20 mg of IVL745 and one treatment period placebo. Both treatments were taken twice daily for 7 days, with a single dose on day 8. Treatments were separated by a washout period of at least 2 weeks. On day 7 of each treatment period, sputum was induced and collected, and exhaled nitric oxide (NO) was measured. On day 8, an inhaled bolus allergen challenge was performed, and blood was taken for pharmacokinetics. On day 9, exhaled NO was measured, and a methacholine challenge was done. On day 10, sputum was induced and collected. Adverse events, peak expiratory flow (PEF), use of short-acting β 2 -agonists, and asthma symptoms were recorded daily throughout the study. Results There was no statistically significant difference between IVL745 and placebo in the effect on the LAR after allergen challenge, as measured by the area under the curve of the percentage change in FEV 1 from the prechallenge baseline (mean [SEM], −81.99 [18.80] after IVL745 and −72.58 [21.29] after placebo; 95% CI of difference, −36 to 16.8; P = .46) or by the maximum percentage change from the prechallenge baseline (mean [SEM], −23.44 [4.73] after IVL745 and −21.30 [5.17] after placebo; 95% CI of difference, −11 to 6.29; P = .60). There was a statistically significant decrease in the percentage of eosinophils in sputum on day 7 of treatment with IVL745 (mean [SEM], 7.32 [1.46]) compared with placebo (mean [SEM], 15.00 [1.92]; 95% CI of difference, −13 to −1.2; P = .02). There was no statistically significant difference between IVL745 and placebo with respect to the early asthmatic response, methacholine hyperresponsiveness, exhaled NO, postallergen sputum, symptoms, inhaled β 2 -agonist use, or PEF. Conclusion In patients with mild-to-moderate atopic asthma, IVL745 did not affect the early and late response to inhaled allergen or markers of airway inflammation, except for a modest reduction in sputum eosinophils.

The stepwise electrochemical oxidation of p-methoxyphenol and hydroquinone at boron-doped diamond (BDD) electrodes was investigated in perchloric acid media using rotating ring–disk electrode (RRDE) and hydrodynamic modulation techniques. Initial oxidation of these compounds to p-benzoquinone at the disk may be confirmed by reduction of the quinone at the ring electrode. Further oxidation, ultimately to CO2, can be followed by the loss of redox active products at the ring. Comparison of BDD anodic activity to those of graphite, gold, and platinum electrodes, utilizing RRDE configurations, shows that the high oxygen evolution overpotential exhibited by BDD allows for more efficient anodic conversion of p-methoxyphenol and hydroquinone to products beyond the quinone stage. BDD, unlike the other electrode materials, showed no corrosion or fouling when used under these conditions. These results complement product analysis studies by other groups on BDD for organic contaminant remediation by exhaustive electrolysis.

Postoperative nausea and vomiting (PONV) is a common and distressing event following surgery. About one in four patients are affected. It has an associated morbidity and mortality caused by both the direct effects of vomiting and the difficulties in managing other aspects of postoperative care. This article discusses the five principal areas to be considered when assessing and managing the risks of PONV: premorbid patient issues; the immediate preoperative situation; the nature of the proposed surgery; anaesthetic technique; and the postoperative circumstances. Advances in the understanding of normal physiology and the pathophysiological states induced by any surgical intervention have revealed that a multimodal approach is essential to manage this condition. Treatment must begin in the preoperative period and aim to reduce both physical and psychological risk factors. The anaesthetic technique must be tailored to the type and length of surgery, and a postoperative plan created to reduce the incidence of PONV and provide effective treatments. The importance of the role of polypharmacy is also discussed.

Physical, spectral and chromatographic data for all 209 individual PCB congeners is presented. The individual congeners were synthesized and then isolated and purified.Recent emphasis on the source of the toxicity of commercial PCB formulations has increased the need for a complete set of the PCB congeners. Through the use of two capillary GC columns: 40% octadecyl/ 15% phenyl methyl siloxane and 50% phenyl methyl siloxane, it was possible to separate 201 PCB congeners with only four unresolved pairs. The data compiled in this study for all 209 congeners will aid in the identification of selected individual components of these environmental pollutants. The use of this data also presents the opportunity for the improved quantification of the commercial PCB formulations.

Near field holography is a method of using grating photomasks in which the m = -1 and m = 0 diffracted beams of a UV source interfere to form a standing wave pattern. This simple hologram can then be used to expose a grating pattern on a process wafer when held in near- contact. This technique is especially attractive for use in OEICs and PICs when fabrication of the grating masks is accomplished with e-beam lithography and dry etching, since the diffractive properties of the mask can be controlled by the physical parameters of the mask. The grating period on masks made in this way can be precisely controlled to produce arrays of lasers each separated by only a small change in frequency (order 100 GHz) as may be required for WDM applications. We review the phenomenology of fused silica phase grating masks and describe work toward establishing characterization criteria, implementing practical printing methods, improving e-beam precision, and demonstrating laser array performance. We discuss principle issues and progress in each of the technical areas.

Ba1−xKxBiO3 is to date the highest Tc member of a class of superconductors which, it could be argued, belong in the same class of materials as the copper oxides. While there are striking differences between the bismuthates and the cuprates, there are some similarities. In this paper, we will report the results of our tunneling measurements on BKBO. The determination f the energy gap in this material suggests that it is a relativity weakly coupled BCS superconductor - a similar conclusion is reached in the sister compound BaPb1−xBixO3. These results are substantailly different from similar measurements in the cuprates. In addition, we have studied the background tunneling conductance in four of the compounds in this class (BaPbO3, BaPb1−xSbxO3, BaPb1−xBixO3 and Ba1−xKxBiO3) and find a remarkable correlation between the strength of the linear conductance and the superconducting transition temperature. Finally, the Josephson tunneling in these compounds will be discussed.

Anodic electrosynthesis of Ba 0.6 K 0.4 BiO 3 leads to millimeter-sized crystals of this cubic superconductor with transition temperatures of 30.5 K. Clusters of these lustrous blue-black crystals are grown on gold anodes in graphite crucibles which conveniently serve as the cathode. Details of the electrochemical procedure utilizing a hydroxide melt are given, along with the characterization of the superconductive transition by microwave absorption and magnetic measurements, and confirmation of the composition and structure with X-ray diffraction. The availability of crystals with cubic facets of up to 10 mm 2 has facilitated characterization and application of this material.

A generator—detector mode with the rotating ring—disk electrode has been used to determine the difference between Pd and Pt electrode behaviour and the origin of the larger overpotentials at Pd-hydrogen evolving cathodes. The use of thin film Pd disk electrodes has allowed full hydrogen or deuterium charging of the metal phase in short times. The electrode system has made feasible simultaneous measurements of the hydrogen uptake in PdH x films where the maximum composition reached was PdH 0.81 . Alloying Ni into Pd decreases the maximum hydrogen absorption by solid solution PdNi films to near zero at 17% Ni. The outgassing of hydrogen on open circuit from variously charge electrodes can be followed in real time and shows the losses associated with transfer of specimens to post-analysis (∼6% in 5 min).

Measurements of the flux of copper species reaching the ring electrode of a rotating Nd2CuO4−xFx disk-gold ring electrode configuration in acidified chloride solutions allow for the real-time analysis of x as the superconductor is etched. The method is based on analyzing the ratio of copper oxidation states arising from the open circuit dissolution reaction of the Nd2CuO4−xFx disk into chloride solutions. Through voltammetry at the gold ring electrode, the Cu2+ and Cu1+ products are measured quantitatively and x determined. For specimens showing a 27 K onset of Tc, the average copper oxidation state is 1.74, corresponding to the stoichiometry Nd2CuO3.74F0.26. Superconductor electrode potentials are determined directly by the Cu2+/Cu1+ ratios.

To recover part of the often substantial fraction of the sunlight lost in practical semiconductor-liquid junction solar cells by solution absorption, two designs incorporating fluorescent windows are analyzed and tested. In these schemes the luminescers absorb incident light in regions of electrolyte absorption and re-emit at wavelengths both within the semiconductor band gap and the transparent range of the solution. It is shown that complete separation of the absorption and emission spectra (large Stokes shift) is essential for useful collection of these normally lost quanta. This requirement is not met by most fluorescent dyes, including the many with high quantum efficiency used in dye lasers. It is fulfilled by a europium(III) tetrakis diketonate which was successfully applied in the window of a n-CdSe/Na 2 S-S-Se-NaOH/C cell. A more efficient realization employs two solar cells, one edge-mounted on the fluorescent window to utilize the absorbed light, while the second operates in the conventional mode with light transmitted through the window.

In an electrochemical cell with one electrode rotating asymmetrically with respect to a second fixed electrode, a constant current produces an a.c. component of the voltage between the pair at the rotational frequency. This a.c. signal arises from the varying iR drop between the extremes of rotational position and thus is a measure of the conductivity of the cell electrolyte. When such a rotating electrode is added to an operating two-electrode cell (e.g. a plating bath), the a.c. signal derived from the rotating element may be used additionally to map the spatial current distribution in the cell. The filtered and amplified signal in either system has also been used to trigger a counter for digital measurement of electrode rotational speed.

Photoelectrochemical cells based on III-V semiconductor electrodes have achieved high solar-power conversion efficiencies in regenerative cells and in photoelectrolytic production of hydrogen. In the particular examples of GaAs and InP, which have band gaps well matched to the solar spectrum, these successes have been closely tied to the control of competitive chemical processes following hole-electron pair production. The corrosion chemistry associated with charge transfer at these interfaces, the influence of film formation, and the consequences for both photoanodic and photocathodic cells are discussed.

CdSe x Te 1− x films have been electrodeposited by the co-reduction of a tellurium substrate (to telluride) and soluble SeSO −2 3 (to selenide) in the presence of cadmium complexes. The tellurium film is itself initially electroplated in acidic media from tellurite. The necessary sequence of electrode reactions to allow CdSe x Te 1− x compositions to be formed is regulated by the potentials maintained in the pH 9.6 ammonia buffer-ethylene diamine tetraacetic acid solution. Photoelectrochemical spectroscopy and X-ray diffraction of annealed films were used to characterize the products. In the absence of cadmium ion, the method allows generation of known fluxes of telluride and selenide downstream of the generating electrode surface for other synthetic purposes.

CdS and Bi 2 S 3 films from anodization of the metals in alkaline sulfide solution wereearlier shown to possess the photoelectrochemical and spectral properties of the corresponding n-type crystals, but with lower efficiency in semiconductor-liquid junction solar cells. The formation and removal of these films have been followed by rotating ring-disk electrode (RRDE) voltammetry, under dark and illuminated conditions, to define the regions of sulfide uptake and release, photovoltaic activity, hydroxide participation and mechanism of sulfur generation.

A 12% solar to electrical conversion efficiency and the equivalent of two months operation in sunlight have been realized for a semiconductor liquid junction solar cell. This external efficiency is superior to those of previous photochemical, photosynthetic, or photoelectrochemical systems and approaches the levels of solid state photovoltaic devices which are more complex to fabricate. We review here the problems associated with achieving efficient and stable cells. These difficulties originate from the electrolyte-exposed semiconductor surface, which introduces photocorrosion, light induced ion exchange, interfering surface states, and impurity effects and prevents non-reflective coatings from being applied. We show, for several cells, that solutions exist to these issues.

The cathodic formation of highly active tellurium deposits and of hydrogen telluride in acidic tellurite solution were studied voltammetrically at gold and tellurium rotating disk electrodes with gold or silver rings. Both generation and detection of H 2 Te are dependent on the activity of the tellurium substrate and the presence of Te(IV) in the solution. Electrodeposited Te in perchloric acid solution produces a very rough surface which affects the hydrodynamics of the electrode and leads to the electrochemical activity. This substrate is highly useful in the electrosynthesis of metal tellurides.

As an electrode in aqueous media, Ba 2 YCu 3 O 7 acts as a strongly oxidized, reactive metallic conductor. Understanding this behavior is essential to processing this material and exposing it to atmospheres containing water. Competition between electron transfer reactions to soluble redox couples and substrate degradation limits the potential range over which electrochemistry can be carried out. This aspect has been studied through voltammetry with several kinetically reversible redox systems at Ba 2 YCu 3 O 7 rotating disk electrodes (RDE), supplemented by rotating ring-disk and hydrodynamically modulated RDE techniques to define the reaction paths. Collectively, the data allow prediction of the system behavior from electrode potentials. Parallel experiments with the more stable CuO are performed in each case as a related model substrate.

In this paper we review the growth of bulk single crystals and of epitaxial single crystalline layers of p-type InP. The electrical properties obtained for various dopants (Cd, Zn, Mg, Mn, Be) in bulk crystals and in epitaxial p-InP layers prepared via liquid phase epitaxy, chemical vapor deposition and molecular beam epitaxy are discussed and a comparison is made of the photoluminescence properties of acceptor impurities in bulk InP and MBE epilayers. Also, we evaluate the preparation of polycrystalline films of p-InP on foreign substrates in the context of n-CdS/p-InP solar cells and present preliminary results on the preparation of InP bicrystals with pure tilt boundaries about 〈111〉.

Summary Operational amplifier circuits with an automatic self-biasing feature have been devised. These circuits nearly double the voltage available from a given pair of operational amplifiers for current or potential control applications. The principle used leads to circuit configurations that apply voltages proportional in magnitude but opposite in sign across a load to nearly double the usual voltage compliance. An existing multi-purpose electrochemical device was simply and inexpensively modified to include the self-biasing feature and the higher capability and performance of the resulting instrument were clearly demonstrated.