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Background Acute respiratory distress syndrome (ARDS) is a relatively common condition of varied aetiology associated with high morbidity and mortality. A range of therapies have been proven to be useful for patients with ARDS, including ventilatory and nonventilatory strategies. Prone positioning is one of the nonventilatory strategies and has been proven to be safe and is associated with significant mortality benefit in patients with moderate to severe ARDS. It is now included in several international guidelines as the standard of care for these cases. Objectives The aim of the study was to develop, implement, and evaluate a prone positioning program in two nonmetropolitan, nontertiary intensive care units in South East Queensland. Methods A Plan–Do–Study–Act quality improvement model was used to implement changes in clinical practice in relation to prone positioning of patients. Results A description of the methods used to promote a complex change strategy is provided in this article. Conclusions In this article, we demonstrate the feasibility of introducing a nonventilatory intervention of prone positioning in the management of patients with moderate to severe ARDS in regional intensive care in South East Queensland. This implementation strategy could be replicated and adopted in other similar intensive care units that do not have the ability to provide tertiary services such as extracorporeal life support.

Background: Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population.Methods: AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921.Findings: Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [Interpretation: Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke.Funding: National Health and Medical Research Council of Australia.

Aim of the study Since over 80% of sudden cardiac arrests occur in the home, cardiopulmonary resuscitation (CPR) training for family members of high-risk cardiac patients represents a promising intervention. The use of mobile application-based (mApp) CPR training may facilitate this approach, but evidence regarding its efficacy is lacking. Methods We conducted a multicenter, pragmatic, cluster-randomized trial assessing CPR training for family members of cardiac patients. The interventions were mApp (video, no manikin) and VSI (video + manikin). CPR skills were evaluated 6-months post-training. We hypothesized that chest compression (CC) rate from training with an mApp would be no worse than 5 compressions per minute (CPM) lower compared to VSI. Results From 01/2016 to 01/2018, we enrolled 1325 eligible participants (mean age 51.6 years, 68.2% female and 59.4% white). CPR skills were evaluated 6-months post-training in 541 participants (275 VSI, 266 mApp). Mean rate was 84.6 CPM (95% CI: 80.4, 88.6) in VSI, compared to 82.7 CPM (95% CI: 76.2, 89.1) in the mApp, and mean depth was 42.1 mm (95% CI: 40.3, 43.8) in VSI, compared to 38.9 mm (95% CI: 36.2, 41.6) in the mApp. After adjustment, the mean difference in CC rate was −2.3 CPM (95% CI −9.4, 4.8, p = 0.25, non-inferiority) and CC depth was −3.2 mm (95% CI −5.9, 0.1, p = 0.056). Conclusion In this large prospective trial of CPR skill retention for family members of cardiac patients, mApp training was associated with lower CC quality. Future work is required to understand additional approaches to improve CPR skill retention. Clinical Trial Registration URL: ClinicalTrials.gov, Identifier: NCT02548793 .

There is considerable evidence of widespread damage in the 7th millennium habitation sites across Jordan. The origins of this damage are unknown, but the most widely accepted hypothesis associates the resulting rubble and gravel deposits with the Holocene Rapid Climate Change. One way of testing the various hypotheses is to provide a more reliable chronology for the event(s) in question. In this study, we used quartz OSL and feldspar IRSL signals to date accumulative rubble layers at two archaeological sites in Southern Jordan; Ba'ja and Basta. By comparison with the OSL ages, the IRSL ages demonstrate that most of the quartz samples were sufficiently well bleached at deposition to provide accurate ages. Quartz ages show that deposition of the rubble layers took place in different episodes starting around 8.5 ka and 6.0 ka. Ages from Ba'ja site agree with the archaeological expectations of time of deposition. However, the results from Basta are younger than the archaeological expectations, which are based mainly on architectural style and stratigraphy.

Mass-transport sediments are generally difficult to date directly by existing methods. Conventional luminescence dating of sand is unsuitable because the short transport distances provide little opportunity for bleaching. However, larger clasts are often exposed to sunlight for prolonged periods before becoming entrained in mass-movements, and these clasts have the potential to be used for rock-surface luminescence dating. Mass-transport is a major component of landscape change in mountain regions; in the Baksan valley, Caucasus Mountains, high uplift rates and high precipitation create a rapidly eroding landscape where preservation of sediments is poor. The area is particularly prone to destructive debris flows, because of the large quantity of detrital material in the catchments. The debris-flow and hillslope sediment the Baksan valley are used here to test the applicability of rock-surface burial dating to mass-transport sediment. We find that colluvial clasts show a high degree of bleaching and give reproducible ages, with a large colluvial deposit dated to the early–mid Holocene. The bleaching of debris flow clasts is more variable – we suppose due to the more complex transport history of the clasts, with opportunities for lengthy storage in moraines or colluvium. Overall, the results are encouraging, and suggest that rock-surface methods can provide a useful approach to mass-transport dating in mountainous regions. However, improved targeting of samples and measurement efficiency is desirable for widespread application.

This study presents results for pyrolysis experiments conducted on immature Type II and IIs source rocks (Kimmeridge Clay, Dorset UK, and Monterey shale, California, USA respectively) to investigate the impact of high water pressure on source rock maturation and petroleum (oil and gas) generation. Using a 25 ml Hastalloy vessel, the source rocks were pyrolysed at low (180 and 245 bar) and high (500, 700 and 900 bar) water pressure hydrous conditions at 350 °C and 380 °C for between 6 and 24 h. For the Kimmeridge Clay (KCF) at 350 °C, Rock Eval HI of the pyrolysed rock residues were 30–44 mg/g higher between 6 h and 12 h at 900 bar than at 180 bar. Also at 350 °C for 24 h the gas, expelled oil, and vitrinite reflectance (VR) were all reduced by 46%, 61%, and 0.25% Ro respectively at 900 bar compared with 180 bar. At 380 °C the retardation effect of pressure on the KCF was less significant for gas generation. However, oil yield and VR were reduced by 47% and 0.3% Ro respectively, and Rock Eval HI was also higher by 28 mg/g at 900 bar compared with 245 bar at 12 h. The huge decrease in gas and oil yields and the VR observed with an increase in water pressure at 350 °C for 24 h and 380 °C for 12 h (maximum oil generation) were also observed for all other times and temperatures investigated for the KCF and the Monterey shale. This shows that high water pressure significantly retards petroleum generation and source rock maturation. The retardation of oil generation and expulsion resulted in significant amounts of bitumen and oil being retained in the rocks pyrolysed at high pressures, suggesting that pressure is a possible mechanism for retaining petroleum (bitumen and oil) in source rocks. This retention of petroleum within the rock provides a mechanism for oil-prone source rocks to become potential shale gas reservoirs. The implications from this study are that in geological basins, pressure, temperature and time will all exert significant control on the extent of petroleum generation and source rock maturation for Type II source rocks, and that the petroleum retained in the rocks at high pressures may explain in part why oil-prone source rocks contain the most prolific shale gas resources.

Previous SAR-OSL dating studies using quartz extracted from Romanian and Serbian loess samples report SAR-OSL dose–response curves on fine grained (4–11 μm) quartz that grow to much higher doses compared to those of coarse-grained (63–90, 90–125, 125–180 μm) quartz. Furthermore, quartz SAR-OSL laboratory dose response curves do not reflect the growth of the OSL signal in nature. A main difference in coarse- and fine-grained quartz dating lies in the alpha irradiation history, but the effect of mixed alpha-beta fields has so far received little attention. In the present study we investigate whether the alpha dose experienced by fine grains over geological cycles of irradiation and bleaching may have an effect on the saturation characteristics of the laboratory dose response. By applying time resolved optically stimulated luminescence we confirm that the OSL signals induced in quartz by alpha and beta radiation follow the same recombination path. We also show that a mixed alpha-beta dose response reproduces the beta dose response only up to about 800 Gy. Assuming an a-value of 0.04 we have shown that laboratory alpha and beta dose response curves overlap up to effective alpha doses of ∼50 Gy. Based on these results, we conclude that exposure of fine grains to alpha radiation during burial and transport cycles prior to deposition, as well exposure to the mixed radiation field experienced during burial are not responsible for the age discrepancies previously reported on fine and coarse grained quartz extracted from Romanian and Serbian loess.

We give a theoretical overview of non-fading infrared stimulated luminescence (IRSL) signals in feldspars, followed by intercomparison of potential methods on some sediment extracts. We observe that a more stringent thermal wash on its own is not effective in obtaining a more stable signal, suggesting that the higher the stimulation temperature in post IR-IRSL methods, the greater the ability to access distant electron hole pairs. We further find that the delayed off-time signal in time-resolved IRSL has immense potential for sampling non-fading signal and should be explored further; this signal also appears to be well reset in nature and avoids unwanted thermal transfer effects in comparison to the post IR-IRSL signal measured at 290 °C.

Atrial arrhythmias and premature ventricular contractions (PVCs) are common causes of arrhythmia induced cardiomyopathy (AIC), the hallmark of which is partial or complete reversibility of left ventricular ejection fraction (LVEF) after arrhythmia suppression or elimination. Predictors of myocardial

Summary This report reviews U.S. guidelines for the identification of persons exposed to rubella during air travel. In response to an individual with rubella who traveled on multiple flights, CDC conducted an airline contact investigation that was expanded beyond customary protocol to assess if current operating procedures are adequate. Of 250 potentially exposed airline passengers, 215 (86%) were contacted and none developed a rubella-like rash, arguing against the need to notify passengers beyond the standard protocol in most cases.

In luminescence dating, the two most commonly used natural minerals, quartz and feldspar, are exposed to different dose rates in the natural environment, and so record different doses. The luminescence signals also have different stabilities. For accurate dosimetry, the signals from these two minerals must be separated, either by physical separation of the mineral grains, or by instrumental separation of the luminescence signals. The luminescence signals from quartz and feldspar have different luminescence lifetimes under pulsed optical stimulation. This difference in lifetime can be used to discriminate between the two signals from a mixed quartz-feldspar sample. The purpose of this study is to identify optimum measurement conditions for the best separation of quartz OSL from that of feldspar in a mixed sample using pulsed stimulation and time-resolved OSL. We integrate the signal from 5 μs after the LEDs are switched off until just before the LEDs are switched on again, with the pulse on -time equal to the pulse off -time of 50 μs. By using only the initial interval of the pulsed OSL decay curve (equivalent to 0.2 s of CW-OSL using blue light at 50 mW cm −2 ) we find that the quartz to feldspar pulsed OSL intensity ratio is at a maximum. By using these parameters with an additional infrared (IR) stimulation at 175 °C before measurement (to further reduce the feldspar signal intensity), we obtain a factor of 25 enhancement in signal separation compared to that from a conventional prior-IR CW measurement. This ratio can be further improved if the counting window in the pulse off -time is restricted to detect between 20 and 50 μs instead of the entire off -period.

Exchange of carbon bound hydrogen has been observed when alkenes, saturated and aromatic hydrocarbons are heated at moderate temperatures on carbonaceous surfaces (activated carbon and coal). Isomerisation of alkenes and the formation of hydrogenated/dehydrogenated products from the saturated and aromatic reactants resulted. A suite of crude oils from the Carnarvon Basin (Western Australia) have been analysed with a view to comparing their relative abundances of structurally similar hydrocarbons. The consistent relationships between hydrocarbons in crude oils that are chemically related via hydrogenation/dehydrogenation reactions suggest that a hydrogen exchange process similar to that demonstrated in laboratory experiments occurs during crude oil formation in sedimentary rocks.

Thomsen, K.J., Murray, A.S., Jain, M., Botter-Jensen, L. [2008. Laboratory fading rates of various luminescence signals from feldspar-rich sediment extracts. Radiat. Meas. 43, 1474–1486] have identified a number of feldspar signals which show significantly less anomalous fading than the conventional IRSL signal stimulated at 50 °C and detected in the blue–violet region of the spectrum. One of these was the post-IR IR signal in which first an IR bleach is carried out at a low temperature (e.g. 100 s at 50 °C) and a remaining IRSL signal is measured at an elevated temperature (100 s at 225 °C; detection in the blue–violet region). It is the latter signal that is of interest in this paper. We test such a post-IR IR dating protocol on K-feldspar extracts from a variety of locations and depositional environments and compare the results with those from the conventional IR at 50 °C protocol. Based on laboratory tests (recycling ratio, recuperation, dose recovery) we show that our SAR protocol is suitable for these samples. The observed post-IR IR fading rates (mean g 2days = 1.62 ± 0.06%/decade, n = 24; assuming logarithmic fading) are significantly lower than those measured at 50 °C (mean g 2days = 3.23 ± 0.13%/decade, n = 24). The signal is bleachable in nature although residual doses of the order of a few Gy are to be expected. After fading correction the ages are indistinguishable from those measured by IR at 50 °C over an age range from a few ka to >260 ka. However, the correction factor for anomalous fading is only ∼39% of that of the conventional IR at 50 °C signal. This smaller correction factor makes the new post-IR IR ages much less dependent on the inherent assumptions included in the fading correction model.

It is difficult to relate the IRSL signal from feldspar to a particular region of the TL curve; prior IR stimulation reduces the TL signal over a wide range of temperatures. Such data are apparently consistent with the observation from pulse anneal experiments that a laboratory-induced IRSL signal is detectably eroded by a relatively low temperature preheat. These results can be explained by a distribution of trap depths of IR sensitive traps, and/or by changes in recombination probability induced by IR exposure. To investigate the relative importance of these processes, we first examine the relationship between the loss of blue IRSL and TL signals with preheating, and the effect of prior IRSL on the TL signal. Using IRSL measured at 50 °C and a SAR protocol, we then examine the dependence on preheat temperature of equivalent dose (D e ), laboratory fading rate ( g ), and the resulting luminescence age, from three sedimentary potassium-rich feldspar extracts. We demonstrate that there is no systematic increase in D e for a preheat temperature range from ∼80 °C to ∼320 °C (60 s duration). After fading correction, age plateaus vary slightly over the temperature range examined, but there is no evidence for an increase in age with preheat temperature. We therefore conclude that the main dosimetry trap(s) in feldspar are not significantly eroded by laboratory heating for up to 60 s at 320 °C, and we tentatively identify the source of this IRSL as a TL peak lying between 410 and 420 °C; this suggestion is consistent with a kinetic analysis of sensitivity-corrected IRSL data. The corollary to our observations is that shallow (unstable) traps do not give rise to a significant IRSL signal.

Objective To report the management of a woman who presented with secondary infertility and amenorrhea after 2 Lletz procedures and a cone biopsy and who had cervical stenosis, a foreshortened cervix, and hematometra. Design Case report. Setting Fertility clinic and tertiary hospital. Patient(s) A 34-year-old woman who wanted further children but had had a previous cesarean delivery and then a cone biopsy for cervical intraepithelial neoplasia III that resulted in a foreshortened cervix and cervical obstruction. Intervention(s) Laparoscopic cervical cerclage, IVF, blastocyst tubal transfer, cesarean delivery, hysterectomy. Main Outcome Measure(s) Pregnancy; morbidity for the woman and her infant. Result(s) An intrauterine pregnancy occurred after blastocyst intrafallopian transfer, but there was uterine herniation necessitating premature delivery of a very low-birth-weight infant that had lung problems but is now healthy. The mother later developed a hematometra that ruptured, requiring an emergency hysterectomy from which her recovery was protracted. Conclusion(s) This first report of a blastocyst intrafallopian transfer was associated with an intrauterine pregnancy; however, when the indication for blastocyst tubal transfer of an obstructed cervix is associated with a foreshortened cervix requiring cervical cerclage, there can be major health risks for infant and mother.

The U 6+ ion occupies a double-well potential in SrWO 4 . Spectral hole burning takes place when the ion changes from one well to the other during the process of optical excitation and relaxation. The temperature dependence of hole refilling has been studied in order to determine the nature of the double-well potential and the hole refilling mechanism. Analysis reveals that the refill rate follows a simple Arrhenius equation with a single barrier of 0.013 eV. The high-temperature extrapolated refill rate is extremely low at only 200 s −1 . Possible explanations and the significance of this result to studies of amorphous systems are discussed.

We have investigated the anodic stripping of bismuth layers adsorbed on Pt(110)-(1 × 2) by metal vapour deposition, and through under-potential deposition (upd) from solution. We have also studied the effect of the bismuth layers on hydrogen and oxygen adsorption in ultra-high vacuum (UHV), upd hydrogen adsorption-desorption, and the electro-oxidation of CO in dilute sulphuric acid electrolyte. A bismuth monolayer (0.7 ML) undergoes electro-oxidation at 0.77 V and 0.88 V (vs. Pd | H 2 ) (saturation θ Bi = 0.75), with the lowest potential anodic peak associated with the formation of the bismuth adsorbed at coverages greater than 0.5 ML in the uniaxially compressed structure. An overall charge of two electrons is associated with the oxidation process in the monolayer, whereas three electrons are involved in the anodic stripping of the second layer at 0.59 V, and third and subsequent layers at 0.5 V. Bismuth adsorption results in a linear blocking of the β 2 hydrogen temperature programmed desorption (TPD) state without a shift in the desorption temperature, and total blocking of hydrogen at 0.5 ML of bismuth at the completion of the c(2 × 2) overlayer on the unreconstructed surface. The blocking of the upd hydrogen layer by bismuth is non-linear, and is fastest at lowest coverage of bismuth. At 0.5 ML coverage of bismuth, ca. 0.5 ML of upd hydrogen can be adsorbed, and at 0.7 ML of bismuth 0.25 ML of upd hydrogen is adsorbed. The bismuth does not change the potential of the upd hydrogen adsorption-desorption. CO adsorbed from solution on Pt(110)-(2 × 1) at 0.4 V produces on transfer to UHV the TPD characteristic of 1 ML of CO in the Pt(110)-(2 × 1)plgl overlayer. Electro-oxidation of this layer takes place in an anodic peak in the cyclic voltammetry at 0.69 V. CO adsorbed from solution at 0 V saturates at a coverage of 0.8 ML, and undergoes electro-oxidation at lower potentials, in a broader peak centred at 0.66 V and a small peak at 0.38 V. The effect of bismuth adsorption is to decrease the amount of CO adsorbed, and available for electro-oxidation, at the same rate as CO adsorption is blocked in UHV. Bismuth also has the effect of increasing the electrochemical potential for CO oxidation from 0.69 V on the clean surface to 0.78 V when CO is co-adsorbed with bismuth in the Pt(110)-c(2 × 2) Bi overlayer, or at higher coverages. A shift to a higher CO oxidation potential is observed from the smallest coverages studied, although at 0.1 ML the peak is broad. The electro-oxidation of the CO also strongly influences the subsequent oxidation behaviour of the bismuth which takes place in a highly asymmetric anodic peak at 1.0 V. The potential of CO oxidation in the mixed bismuth CO layer on Pt(110)-(1 × 2) is very similar to that on Pt(111), and the results are explained using a model involving substrate-mediated oxygen transfer in CO electro-oxidation.

We report photoluminescence studies of poly(3-dodecylthiophene) (P3DT) in solution. In a good solvent the polymer exhibits luminescence with a high quantum efficiency and a decay time of 500 ps. In a poor solvent the emission is red shifted with a 20-fold reduction in quantum efficiency and a decay profile that is non-monoexponential, but has an average lifetime that is very similar to the good solvent environment. The data indicate a large increase in the natural radiative lifetime from approximately 1 ns in a good solvent to 20 ns in a poor solvent, which implies an emitting state that is different in the two situations. In the poor solvent the spectrum is almost identical to that of the thin film, suggesting that the polymer aggregates in the solution and the emitting species is the same in both environments. The data are consistent with the formation of an excited state that is not localized on a single chain but is delocalized over more than one chain.

The deposition of rhodium through metal-organic vapour deposition (MOCVD) of [Rh(CO)2Cl]2 and direct metal vapour deposition has been investigated on TiO2(110). The nature and chemistry of the surface rhodium phase has been characterised by TPD, XPS and FT-RAIRS, using CO as a probe adsorbate molecule. The thermal stability and adsorbate induced inter-conversion of the rhodium phases is also investigated. The rhodium geminal dicarbonyl species (Rh(CO)2) is formed by the dissociative adsorption of [Rh(CO)2Cl]2 at 150 K. At this temperature the physisorption of the parent molecule subsequently takes place at higher exposures. The gem-dicarbonyl is observed exclusively during adsorption at 300 K, and is characterised by vsym(C-O) at 2112 cm−1, and vasym(C-O) at 2028 cm−1. These are observed in p-polarised FT-RAIRS by a coupling of vsym(C-O) to the normal component of the field yielding an increased reflectivity (transmission band), and the coupling of vasym(C-O) to the tangential component, yielding a decreased reflectivity (absorption band). The Rh(3d 5 2 ) binding energy of 309.1 eV is close to that of the parent molecule, while the Cl(2p 3 2 ) binding energy of 198.3 eV is clearly shifted from that found for the parent molecule (199.1 eV), and is associated with the adsorption of the chlorine onto the TiO2(110) substrate. The frequencies of the bands of the gem-dicarbonyl shift only ca. 9 cm−1 with coverage which saturates at 0.35 ML. The physisorbed layers are characterised in FT-RAIRS by a complex series of transmission and absorption bands when using p-polarised radiation which arise from the coupling of the radiation to four normal modes of an isotropic layer of the parent molecule. The four normal modes give rise to absorption bands in the p-polarised spectrum, and transmission bands in the s-polarised spectrum, at 2102, 2087, 2039 and 2027 cm−1 correspond closely to values observed in the crystalline solid state. The gem-dicarbonyl is stable to 450 K at which temperature CO is cleanly desorbed, and highly dispersed metal particles are produced. For surfaces heated to 500 K, the gem-dicarbonyl can be partly regenerated by exposure of the surface to CO at 300 K, with additional adsorption of linear CO taking place on the remaining metallic particles, characterised by a strong absorption band with vlinear(C-O) in the range 2064–2071 cm−1. For surfaces heated to 800 K, a narrower distribution of larger metallic particles is produced from which the regeneration of the gem-dicarbonyl is not facilitated by exposure to CO. The adsorption of CO on the metallic particles is characterised by a very low sticking probability, and a small coverage dependent, red frequency shift. This we suggest is associated with the migration of oxygen from the substrate over the surface of the rhodium during heating, and CO adsorption is only possible after sites are made available by the reaction of CO with adsorbed oxygen to produce CO2. Exposure of the gem-dicarbonyl to hydrogen at 300 K leads to partial dccarbonylation, and partial disproportionation of the CO resulting in adsorbed carbon. Re-exposure to CO again results in the partial regeneration of the gem-dicarbonyl species. Rhodium deposition by MVD at 300 K leads initially to layer-by-layer growth of metallic rhodium, and exposure of such layers to CO during or following deposition did not result in the formation of the gem-dicarbonyl species. A facile adsorption of linearly bound CO on these films is observed, with vlinear(C-O) in the range 2024–2090 cm−1 for both submonolayer and multilayer films. The p-polarised FT-RAIRS spectra produced transmission bands for films below ca. 7 ML, and absorption bands above ca. 20 ML. CO desorbs from the films at 420–550 K, and the TiO2(110) substrate appears not to influence the CO adsorption behaviour expected for metallic rhodium, even for the first atomic layer. Heating the rhodium layers to 500 K and above produced rhodium particles which on exposure to CO produced the same characteristics of the large particles of rhodium resulting from the decomposition of the gem-dicarbonyl.

Some nickel-uranium oxides have been prepared by evaporation techniques. The reduction properties of these materials in hydrogen are complex and depend on the initial calcination temperature of the solid and the nickel content. The surface area of the metallic nickel component of the reduced materials increases with increasing nickel content. The uranium oxide component of the catalyst appears to maintain a high dispersion of the metallic nickel and inhibit sintering. The activity of the catalysts for the hydrogenation of carbon dioxide to methane is enhanced in catalysts with high concentrations of high-surface area metallic nickel.

The adsorption of [Rh(CO)2Cl]2, on TiO2(110) has been studied using FT-RAIRS ans XPS, and at 300 K results in dissociation to produce adsorbed chlorine and the rhodium gem-dicarbonyl species Rh(CO)2. The gem-dicarbonyl is characterised in the IR by vsym (CO) and vasym(CO) observed at 2112 and 2028 cm−1, respectively. The gem-dicarbonyl decomposes through loss of CO at 450–500 K to produce metallic rhodium particles, Rh0x. Following heating to 500 K, re-exposure of the surface to ∼ 106 L of CO gives rise to the partial re-generation of the gem-dicarbonyl species, and in addition to the adsorption of linearly bound CO on Rh0x, with v(CO) observed at 2064 cm−1. Desorption of the linear bound species from Rh0xtakes place at 550–600 K. re-generation of the gem-dicarbonyl species also takes place on a surface where adsorbed chlorine has been removed using water adsorption/desorption cycles, but does not appear to involve surface hydroxyl groups or dissociative adsorption of CO. If the surface is heated to 800 K it appears that larger metal clusters are formed which do not allow the regeneration of the gem-dicarbonyl following exposure to ∼ 106 L of CO. Adsorption of CO on these larger particles of Rh0x gives rise to the linear CO species with v(CO) at 2064-2055 cm−1, and shoulders at 2030 and 2010 cm−1. In addition a broad band at 1870 cm−1 is observed which is associated with v(CO) of the bridge bound species.

A range of substituted head-to-tail polythiophene random copolymers containing alkyl and ω-hydroxyalkyl side chains has been synthesized by protection of the alcohol as a tetrahydropyranyl acetal during polymerization. The ω-hydroxyl group can be transformed into an azide which, on heating, decomposes and leads to crosslinking which renders the solid polythiophene film insoluble and modifies its optical properties. An ω-hydroxyalkyl homopolymer has also been synthesized by this route and affords polymers with unexpected optical properties.

We present the photophysics of some soluble poly(3-alkyltbiophenes) (P3ATs) in fluid solution and in the solid state. We have used quantitative time-resolved and steady-state luminescence spectroscopies to examine the photophysics of these polymers in the different environments. We report data that examine the nature of the excited states in these different media and offer an alternative explanation to the low luminescence quantum efficiency of the P3AT films in terms of a decrease in the natural radiative lifetime of the emitting state. The importance of the solvating alkyl groups will be discussed in terms of the excited state dynamics, the nature of the excited states and the influence on both the solvato — and thermochromic properties of these polymers.

The adsorption of bismuth on Pt(110)−(1 × 2), and its coadsorption with CO, has been investigated using TPD, XPS, LEED and work function measurements. Bismuth adsorption lifts the (1 × 2) surface reconstruction at coverages θBi > 0.3. The adsorbate induced lifting of the clean surface reconstruction is activated, and annealing the surface above 350 K results in more complete ordering and the formation of a series of ordered bismuth overlayers on Pt(110)−(1 × 1). At θBi = 0.5, a c(2 × 2) structure is observed. LEED measurements indicate that higher coverages are achieved by a uniaxial compression of this centered overlayer structure, subsequently converting above θBi = 0.7 to a (3 × 1) and streaked (4 × 1) structure. Saturation coverage is estimated to be θBi = 0.75. Bismuth blocks CO adsorption through a local, short range interaction, resulting in a linear decrease in CO coverage with increasing bismuth coverage. CO adsorption is completely poisoned at the saturation coverage of θBi = 0.75. Coadsorption of low coverages of bismuth with CO produces a new, c(2 × 4) structure which we associate with an ordered mixed phase of the adsorbates with θCO = 0.5 and θBi = 0.25. At higher coverages of bismuth, the co-adsorbed CO phase does not disrupt the ordered bismuth layers observed in the absence of CO. Bismuth adsorption also favours the desorption of CO from the low temperature (α) desorption peak, which we associate with repulsive interactions.

Intercellular matrices secreted by chick embryo fibroblasts in culture were studied by scanning electron microscopy. Cell-cell contact is a prerequisite for the expression of such matrices. The smallest fiber detected by transmission electron microscopy is 5--10 nm in diameter. These matrix fibers tend to cluster to form bundles. Immunofluorescence and immunoferritin procedures reveal that LETS protein is one of the components of the matrices. The matrices are isolated from other cellular organelles by detergent treatment. More than 90% of the proteins in cell-free matrices are LETS protein, suggesting that the matrices are probably made of only one component--LETS protein. Since the solubilization of matrices requires beta-mercaptoethanol, LETS protein matrices may be the first known polymer system in nature to use disulfide linkage as an intermolecular polymerization vehicle. Collagen does not appear to be involved in such matrices. The LETS protein matrix supports the morphological conversion of rounded cells into spindle-shaped, and also promotes myoblast fusion. It does not, however, exert an effect upon cell growth, the rate of glucose uptake or protease production.