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The objective was to compare the performance of the updated Charlson comorbidity index (uCCI) and classical CCI (cCCI) in predicting 30-day mortality in patients with Staphylococcus aureus bacteraemia (SAB). All cases of SAB in patients aged ⩾14 years identified at the Microbiology Unit were included prospectively and followed. Comorbidity was evaluated using the cCCI and uCCI. Relevant variables associated with SAB-related mortality, along with cCCI or uCCI scores, were entered into multivariate logistic regression models. Global model fit, model calibration and predictive validity of each model were evaluated and compared. In total, 257 episodes of SAB in 239 patients were included (mean age 74 years; 65% were male). The mean cCCI and uCCI scores were 3.6 (standard deviation, 2.4) and 2.9 (2.3), respectively; 161 (63%) cases had cCCI score ⩾3 and 89 (35%) cases had uCCI score ⩾4. Sixty-five (25%) patients died within 30 days. The cCCI score was not related to mortality in any model, but uCCI score ⩾4 was an independent factor of 30-day mortality (odds ratio, 1.98; 95% confidence interval, 1.05–3.74). The uCCI is a more up-to-date, refined and parsimonious prognostic mortality score than the cCCI; it may thus serve better than the latter in the identification of patients with SAB with worse prognoses.
Increasingly, the evidence from optical and infra–red wavebands suggests that the difference between Seyfert 1 and Seyfert 2 nuclei is due largely to orientation effects rather than intrinsic differences between the two classes, but the evidence from radio observations has been less clear–cut. We have observed the CfA Seyfert Sample at 8.4 GHz using the VLA in A– and C–configurations. At this frequency our A–array maps have a resolution of 0.25″ – much higher than those achieved in previous surveys – whilst the 3″ C–array beam is ideal for measuring the total radio flux of the active nucleus. The 1–sigma noise in both sets of observations was 70 μJy.
Since the date of the 1935 Paris meeting two total eclipses have been successfully observed. Throughout the long path crossing Siberia and Japan the weather on June 19, 1936 on the whole about lived up to predictions. On account of widely scattered clouds neighbouring expeditions had quite different luck with the weather. In contrast, the June 8, 1937 eclipse was seen throughout the whole track under universally clear skies, which is all the more surprising for the reason that eclipse expeditions to the tropics usually fare badly with the weather. Stewart and Stokley in a ship at sea were able to observe the eclipse with a measured duration of 7 min. 6 sec., the longest period of totality in 1200 years.
An obesity paradox has been proposed in many conditions including HIV. Studies conducted to investigate obesity and its effect on HIV disease progression have been inconclusive and are lacking for African settings. This study investigated the relationship between overweight/obesity (BMI≥25 kg/m2) and HIV disease progression in HIV+ asymptomatic adults not on antiretroviral treatment (ART) in Botswana over 18 months. A cohort study in asymptomatic, ART-naïve, HIV+ adults included 217 participants, 139 with BMI of 18·0–24·9 kg/m2 and seventy-eight participants with BMI≥25 kg/m2. The primary outcome was time to event (≥25 % decrease in cluster of differentiation 4 (CD4) cell count) during 18 months of follow-up; secondary outcomes were time to event of CD4 cell count<250 cells/µl and AIDS-defining conditions. Proportional survival hazard models were used to compare hazard ratios (HR) on time to events of HIV disease progression over 18 months. Higher baseline BMI was associated with significantly lower risk of an AIDS-defining condition during the follow-up (HR 0·218; 95 % CI 0·068, 0·701; P=0·011). Higher fat mass at baseline was also significantly associated with decreased risk of AIDS-defining conditions during the follow-up (HR 0·855; 95 % CI 0·741, 0·987; P=0·033) and the combined outcome of having CD4 cell count≤250/µl and AIDS-defining conditions, whichever occurred earlier (HR 0·918; 95 % CI 0·847, 0·994; P=0·036). All models were adjusted for covariates. Higher BMI and fat mass among the HIV-infected, ART-naïve participants were associated with slower disease progression. Mechanistic research is needed to evaluate the association between BMI, fat mass and HIV disease progression.
Using Hubble Space Telescope WFPC2 images of 3CR compact steep spectrum (CSS) radio sources and literature radio maps makes detailed comparison between optical and radio structures possible. All CSS sources for which the optical and radio orientation can reliably be measured, display good alignment between the optical and radio emission. This alignment is observed down to the lowest redshift in the sample, at z ~ 0.1. Optical emission from CSS galaxies is found to be dominated by this aligned component, especially at higher redshifts. Both the alignment and the relative brightness of this component indicate that CSS sources have large amounts of matter co-spatial with the radio structure. In order to assess the nature of the aligned light, we calculated line emission contamination in the passband using ground based spectra. From this we can conclude that at least in some sources (notably 3C 213.1, 3C346, and 3C 380) line emission is not important. The detailed optical–radio correspondence makes optical synchrotron the most likely mechanism for these three sources.
From the photoinduced transport of energy that accompanies photosynthesis to the transcontinental transmission of optical data that enable the Internet, our world relies and thrives on optical signals. To highlight the importance of optics to society, the United Nations designated 2015 as “The International Year of Light and Light-based Technologies.” Although conventional optical technologies are limited by diffraction, plasmons—collective oscillations of free electrons in a conductor—allow optical signals to be tailored with nanoscale precision. Following decades of fundamental research, several plasmonic technologies have now emerged on the market, and numerous industrial breakthroughs are imminent. This article highlights recent industrially relevant advances in plasmonics, including plasmonic materials and devices for energy; for medical sensing, imaging, and therapeutics; and for information technology. Some of the most exciting industrial applications include solar-driven water purifiers, cell phone Raman spectrometers, high-density holographic displays, photothermal cancer therapeutics, and nanophotonic integrated circuits. We describe the fundamental scientific concepts behind these and related technologies, as well as the successes and challenges associated with technology transfer.
Keratitis is an ocular emergency that can lead to severe visual disability and requires prompt diagnosis and treatment. Sequelae can vary in severity from little or no visual loss to corneal scarring, perforation, endophthalmitis, and loss of the eye. Although the corneal surface is awash with microorganisms of the normal flora, an intact corneal epithelium and ocular defense mechanism serve to prevent infection in the normal eye. Although some organisms such as Neisseria gonorrhoeae, Neisseria meningitidis, Corynebacterium diptheriae, Listeria, and Shigella can penetrate an intact epithelium, all others require damage to the epithelial layer to invade the cornea. Several risk factors predispose the cornea to infection. Dry eyes from Sjogren syndrome, Stevens–Johnson syndrome, or vitamin A deficiency can result in bacterial keratitis. Prolonged corneal exposure from ectropion, lagophthalmos, or proptosis can lead to secondary infection. Entropion and trichiasis resulting in epithelial defects put the cornea at risk. Neurotropic keratopathy from cranial neuropathy, prior herpes simplex, or zoster infections predispose to secondary infections. Some systemic conditions such as chronic alcoholism, severe malnutrition, immunosuppressive drug use, immunodeficiency syndromes, and malignancy can impair immune defenses and allow infection by unusual organisms. Prior ocular surgery such as penetrating keratoplasty or refractive procedures is also a risk factor. Trauma is a common predisposing factor of bacterial keratitis, especially for patients at the extremes of age and in developing countries. Injury to the corneal surface and stroma allows invasion of normal flora as well as organisms harbored by foreign bodies.
Contact lens wear is the most common established risk factor for bacterial keratitis in developed countries. All types of contact lenses have been linked to infection, with extended-wear soft lenses conferring greater risk than daily wear hard or soft lenses. Corneal changes from contact lens use include an induced hypoxic and hypercapnic state promoting epithelial cell derangement and allowing bacterial invasion. Contact lenses also induce dry eye and corneal hypesthesia. Overnight rigid gas-permeable lens use for orthokeratology has also been associated with bacterial keratitis, but with a disproportionately high incidence of Acanthamoeba keratitis.
The directional dark-field signal obtained with X-ray grating interferometry yields direction-dependent information about the X-ray scattering taking place inside the examined sample. It allows examination of its morphology without the requirement of resolving the micrometer size structures directly causing the scattering. The local morphology in turn gives rise to macroscopic mechanical properties of the investigated specimen. In this study, we investigate the relation between the biomechanical elasticity (Young’s modulus) and the measured directional dark-field parameters of a well-defined sample made of wood. In our proof-of-principle experiment, we found a correlation between Young’s modulus, the average dark-field signal, and the average dark-field anisotropy. Hence, we are able to show that directional dark-field imaging is a new method to predict mechanical sample properties. As grating interferometry provides absorption, phase-contrast, and dark-field data at the same time, this technique appears promising to combine imaging and mechanical testing in a single testing stage. Therefore, we believe that directional dark-field imaging will have a large impact in the materials science world.
We have obtained HST/STIS long slit spectroscopy of the aligned emission line nebulae in three compact steep spectrum (CSS) radio sources — 3C 67, 3C 277.1, and 3C 303.1. We find systematic offsets (˜300–500 kms) of the emission line velocities on one or both sides of the radio sources. We also see evidence for broad lines (FWHM ˜500 kms) and complex emission line profiles. In 3C 303.1 the data are consistent with multiple components and possibly split lines. The amplitude of the velocity variations is not so large as to exclude gravitationally-induced motions. However, the complex kinematics, the lack of a signature of Keplerian rotation, and the association of the velocity variations with the radio lobes are consistent with the observed ˜300–500 kms velocities being driven by the expansion of the radio source. Acceleration of the clouds by the bow shock is plausible given the estimated densities in the clouds and the velocities observed in the much smaller compact symmetric objects and with expansion velocities estimated from spectral ageing. This conclusion is unchanged if we consider the scenario in which the cloud acceleration is dominated by the post bow shock flow.
We have obtained long slit spectra of 3C 67 and 3C 277.1 with the HST/STIS spectrograph. We present our preliminary results on the diagnostic emission line ratios along the radio source axes in 3C 67 and 3C 277.1.
The development of the triphenylethylene derivatives has been a major advance in the treatment of breast carcinoma, due to their low toxicity. Currently there is controversy not only about their mode of action but in three main areas of clinical practice: (A) adjuvant therapy in premenopausal and oestrogen receptor-negative cases; (B) primary therapy in the elderly; (C) the prevention of breast cancer.
The United States' National Institute of Health consensus of 1985 that adjuvant tamoxifen be confined to postmenopausal women with positive nodes and ER positive tumours has been refuted by randomised clinical trials. The evidence that ER negative tumours also respond to tamoxifen has added to laboratory evidence that tamoxifen acts other than purely by oestrogen antagonism at the ER.
The use of tamoxifen as sole treatment in primary breast cancer in the elderly is being evaluated in randomised clinical trials. Two that have been reported so far have flaws which make their contradictory conclusions difficult to assess.
Recent results from the CRC trial suggest that tamoxifen has more benefit than simply preventing cancer deaths and clarification of the effects of triphenylethylenes on bone metabolism and the cardiovascular system may strengthen the case for a trial of prophylactic tamoxifen in those at risk of developing breast carcinoma.
Increasing the elastic modulus and hardness of low K films is one of the key
challenges towards integration of these materials into future integrated
circuits. Several approaches are explored for increasing the hardness of
carbon doped oxide (CDO) dielectrics. Several low K precursors and their
mixtures specifically chosen to enhance the hardness (H) and modulus (E) of
CDO films through chemically induced cross-linking. Composition and FTIR
measurements suggest the presence of C-C and C-Si cross-linking with
concurrent observation of improved film hardness and modulus at relatively
low deposition temperatures. Films deposited at 373°C using
diethoxy-methyl-oxiranyl have a hardness and modulus of 2.5 GPa and 18.1 GPa
respectively. Films deposited at 180°C using tetramethylcyclotetrasiloxane
(TMCTS) and 25% hardener have hardness and modulus of 1.5 GPa and 9.4 GPa,
respectively. These film properties are significantly higher than those
observed for TMCTS alone under similar deposition conditions. Based on these
results a low temperature process with 25% hardener and 75% TMCTS combined
with a porogen was used to produce a porous film with a k<2.5 and a
hardness of 0.72GPa.
Highly oriented proteins with characteristic nanometer dimensions are used as a template for the synthesis and support of metallic nanoparticles. Following a bottom-up approach, noble metal particles in the nanometer size range were obtained by the reduction of the corresponding metal salts in the presence of the protein assemblies. The catalytic activity of the protein-supported particles was determined by hydrogenation reactions.
A unique approach to MOCVD of complex oxides enables deposition of a number of materials of technological importance through the use of liquid delivery of metalorganic precursors. Methodologies for control of composition and exploration of. process space are compared for two film systems, one in a relatively mature state of development ((Ba,Sr)Ti03), the other in an early state of development (Ni-ferrite). In both cases, composition was controlled by mixing metalorganic precursors dissolved in solvents using a liquid delivery system. Films with excellent crystalline quality were deposited in both cases. Polycrystalline BST films displayed properties suitable for DRAM applications: charge storage densities > 80 fF/μm2 and leakage current density < 10−8 A/cm2 for films as thin as 15 nm. Growth mechanisms and rates were determined for the single component oxides of the ferrite films. Epitaxial NiFe204 films were deposited on MgO single crystal substrates at 650°C; x-ray rocking curves yielded FWHM values of 0.046°, commensurate with the substrate.
Metal ß‐diketonate complexes are common precursors for chemical vapor deposition (CVD) of a wide variety of thin‐film materials. Liquid delivery CVD has been used to deposit high dielectric constant materials, such as BaxSr1‐xTiO3. This method relies upon volumetric metering of organic soluble precursors, “flash” vaporization to transport the reactants into the gas‐phase and subsequent thermal decomposition onto the heated substrate. This approach enables the precise control of deposited film stoichiometry. In this study, simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to examine the transport and thermal decomposition properties of M(thd)2 (M = Sr, Ba) and Ti(O‐i‐Pr)2(thd)2. In an argon atmosphere, vaporization and transport are observed below 400 °C. In oxidizing atmospheres, such as nitrous oxide and oxygen, decomposition leads to metal carbonate formation as evidenced by both the mass balance and x‐ray diffraction patterns of the residual solids. In the presence of an equimolar amount of the Ti precursor, the formation of carbonates is not observed and oxides are produced at greatly reduced temperatures. Based upon this data, a cooperative oxidation mechanism is proposed which results in “clean” precursor decomposition and BST oxide formation at temperatures near 500 °C.
SrxBiyTa2O5+x+3y/2 (SBT) is a promising material for ferroelectric random access memories (FeRAM's) because of its inherently high resistance to fatigue and imprint. Metalorganic chemical vapor deposition (MOCVD) offers the ability to produce high quality, conformal SBT films for both high and low density memory applications. An MOCVD process based on liquid delivery and flash vaporization has been developed which allows precise control of film stoichiometry and thickness. In this study, wavelength dispersive x-ray fluorescence and x-ray diffractometry have been used to survey composition and preferred crystallographic orientation (texture) relationships. It is shown that as-deposited film composition can be used to influence the texture of the Aurivillius phase in the annealed film. The polarization of the films increases with increasing (115) and (200)/(020) peak intensity due to the relationship of the electric field direction with the polarization direction in the film. The highest values of polarization are found with Sr content, x<0.8 and Bi content, 2.1 <y<2.6.
Chemical vapor deposition (CVD) of noble metal thin-films is increasingly important for future memory storage applications. Integration of ferroelectric perovskites and/or high permittivity oxides requires specialized metal interconnect technologies. Platinum and iridium are two preferred metal electrode materials being explored since they are highly resistant to corrosion and exhibit excellent stability at high temperatures. Further, the formation of stable oxides (IrO2) provides a mechanism for decreased inter-diffusion of oxygen and elemental film constituents, and provides improved reliability in silicon-based devices. CVD provides conformal electrode films that are required to achieve high-densities; high purity films of both platinum and iridium were deposited in this research, using (β-diketonate)Ir(I)L and (MeCp)Me3Pt(IV) as the precursors.
Concurrently, chemical etching of these metals is highly desirable for creating patterns of the electrical contacts and for CVD reactor cleaning. To date, etching of noble metal electrodes has relied upon physical sputtering or chemically assisted etching. In this paper, we also report the first chemical etching of iridium films under ambient conditions, such as room temperature.
High-purity alkaline earth ß-diketonate compounds such as [M(thd)2]x (M = Mg, Ca, Sr, Ba) have been utilized for liquid delivery MOCVD. The “parent” compounds are oligomeric species with bridging ß-diketonate ligands and display both limited volatility and thermal instability. To enhance the precursor transport and film growth rates, Lewis base ligands are used to produce mononuclear precursors. Lewis base coordinated metal (ß-diketonates) also exhibit increased solubilities in organic solvents. In this study, two classes of Group II ß-diketonates were compared; thermal stability and transport were evaluated by simultaneous thermal analyses, using both thermogravimetric (TGA) and differential scanning calorimetry (DSC). Liquid delivery and vaporization were evaluated in an “experimental” liquid delivery system and preliminary film growth, including electrical film properties were measured. The identity of the Lewis base and Group II precursor molecular structure as relates to liquid delivery vaporization and CVD film growth of BaxSr1–xTiO3 are described.
Chemical studies on 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) were conducted to elucidate its thermal behaviors with water and under various reaction conditions. TMCTS was heated in the presence of 316L stainless steel and in the presence of water. The heated TMCTS then was evaluated using 1H NMR (proton nuclear magnetic resonance) spectroscopy, GC-MS (gas chromatography-mass spectrometry) as a function of time, temperature and residual water concentration. The thermal degradation kinetics of gas-phase TMCTS were investigated using FTIR (Fourier transform infrared) spectroscopy at elevated temperatures. These initial results indicated that TMCTS degradation rates increased with both temperature and water concentration. This work spawned the development of a “dry” TMCTS that is expected to exhibit enhanced thermal stability relative towards uncontrolled decomposition.