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Determine the effectiveness of a personal protective equipment (PPE)-free zone intervention on healthcare personnel (HCP) entry hand hygiene (HH) and PPE donning compliance in rooms of patients in contact precautions.
Quasi-experimental, multicenter intervention, before-and-after study with concurrent controls.
All patient rooms on contact precautions on 16 units (5 medical-surgical, 6 intensive care, 5 specialty care units) at 3 acute-care facilities (2 academic medical centers, 1 Veterans Affairs hospital). Observations of PPE donning and entry HH compliance by HCP were conducted during both study phases. Surveys of HCP perceptions of the PPE-free zone were distributed in both study phases.
A PPE-free zone, where a low-risk area inside door thresholds of contact precautions rooms was demarcated by red tape on the floor. Inside this area, HCP were not required to wear PPE.
We observed 3,970 room entries. HH compliance did not change between study phases among intervention units (relative risk [RR], 0.92; P = .29) and declined in control units (RR, 0.70; P = .005); however, the PPE-free zone did not significantly affect compliance (P = .07). The PPE-free zone effect on HH was significant only for rooms on enteric precautions (P = .008). PPE use was not significantly different before versus after the intervention (P = .15). HCP perceived the zone positively; 65% agreed that it facilitated communication and 66.8% agreed that it permitted checking on patients more frequently.
HCP viewed the PPE-free zone favorably and it did not adversely affect PPE or HH compliance. Future infection prevention interventions should consider the complex sociotechnical system factors influencing behavior change.
We present very detailed images of the photosphere of an AGB star obtained with the PIONIER instrument, installed at the Very Large Telescope Interferometer (VLTI). The images show a well defined stellar disc populated by a few convective patterns. Thanks to the high precision of the observations we are able to derive the contrast and granulation horizontal scale of the convective pattern for the first time in a direct way. Such quantities are then compared with scaling relations between granule size, effective temperature, and surface gravity that are predicted by simulations of stellar surface convection.
To test the hypothesis that long-term care facility (LTCF) residents with Clostridium difficile infection (CDI) or asymptomatic carriage of toxigenic strains are an important source of transmission in the LTCF and in the hospital during acute-care admissions.
A 6-month cohort study with identification of transmission events was conducted based on tracking of patient movement combined with restriction endonuclease analysis (REA) and whole-genome sequencing (WGS).
Veterans Affairs hospital and affiliated LTCF.
The study included 29 LTCF residents identified as asymptomatic carriers of toxigenic C. difficile based on every other week perirectal screening and 37 healthcare facility-associated CDI cases (ie, diagnosis >3 days after admission or within 4 weeks of discharge to the community), including 26 hospital-associated and 11 LTCF-associated cases.
Of the 37 CDI cases, 7 (18·9%) were linked to LTCF residents with LTCF-associated CDI or asymptomatic carriage, including 3 of 26 hospital-associated CDI cases (11·5%) and 4 of 11 LTCF-associated cases (36·4%). Of the 7 transmissions linked to LTCF residents, 5 (71·4%) were linked to asymptomatic carriers versus 2 (28·6%) to CDI cases, and all involved transmission of epidemic BI/NAP1/027 strains. No incident hospital-associated CDI cases were linked to other hospital-associated CDI cases.
Our findings suggest that LTCF residents with asymptomatic carriage of C. difficile or CDI contribute to transmission both in the LTCF and in the affiliated hospital during acute-care admissions. Greater emphasis on infection control measures and antimicrobial stewardship in LTCFs is needed, and these efforts should focus on LTCF residents during hospital admissions.
Coinfection with human immunodeficiency virus (HIV) and viral hepatitis is associated with high morbidity and mortality in the absence of clinical management, making identification of these cases crucial. We examined characteristics of HIV and viral hepatitis coinfections by using surveillance data from 15 US states and two cities. Each jurisdiction used an automated deterministic matching method to link surveillance data for persons with reported acute and chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infections, to persons reported with HIV infection. Of the 504 398 persons living with diagnosed HIV infection at the end of 2014, 2.0% were coinfected with HBV and 6.7% were coinfected with HCV. Of the 269 884 persons ever reported with HBV, 5.2% were reported with HIV. Of the 1 093 050 persons ever reported with HCV, 4.3% were reported with HIV. A greater proportion of persons coinfected with HIV and HBV were males and blacks/African Americans, compared with those with HIV monoinfection. Persons who inject drugs represented a greater proportion of those coinfected with HIV and HCV, compared with those with HIV monoinfection. Matching HIV and viral hepatitis surveillance data highlights epidemiological characteristics of persons coinfected and can be used to routinely monitor health status and guide state and national public health interventions.
A multi-scale analysis, ranging from μm → nm → Å-scaie on the influence of thermal treatment on the thermotropic copolyester based on 60 mol% (l,4)-hydroxybenzoic acid (B), 5 mol% (2,6)-hydroxynaphthoic acid (N), 17.5 mol% terephthalic acid (T) and 17.5 mol% biphenol (BP) - COTBP- was carried out. The Å and nm-scale structure was investigated by synchrotron scattering (WAXS and SAXS). Extruded tapes ca. 30 μm thick were annealed at 300 °C under air, without tension. WAXS revealed fibre-like structure with crystalline order, whereas SAXS patterns exhibited diamond-shaped diffuse scattering and discrete meridional scattering elucidating structures along the fibre axis and periodic crystallites. Heat treatment produced roughness reduction, and WAXS patterns showed reflections sharpening indicating an improvement of molecular register and packing (molecular alignment and degree of crystallinity Χ increased). Thermal treatment increased the thermal stability, melting transition and tensile Young’s modulus, E, along extrusion axis, whereas nanoindentation showed decrease of hardness and elastic modulus. Hence, a thermally-induced seif-reinforcing effect was evidenced, with microstructure reorganization correlating with improved thermo-mechanical properties.
The paper analyzes the issues relating to the applicability of innovative material systems for flexible composite armors. The authors made several samplings of aramid fibers (Kevlar 49) by replacing the epoxy resin base, which is often described in the literature, with the thermoplastic matrix - polyethylene (HDPE) and polypropylene (PP). The samples were fired with .38 Special Full Metal Jacketed (FMJ) ammunition produced by the S&B Company, and then the process of firing was modeled in the ABAQUS program. The advantages and disadvantages of the new material system including the possibility of its use in the construction of hybrid composite armors have been presented on the basis of the results of numerical analyses and ballistic tests.
Initial infection with the sentinel respiratory pathogen in children with cystic fibrosis (CF), Pseudomonas aeruginosa (Pa), is generally with environmental strains of this ubiquitous organism. The purpose of this study was to evaluate the associations between meteorological and geographical factors and risk of initial Pa acquisition in young children with CF. Using the U.S. Cystic Fibrosis Foundation Patient Registry from 2003 to 2009, 3463 patients met inclusion criteria, of which 48% (n = 1659) acquired Pa during follow-up. From multivariable Weibull regression, increased risk of Pa acquisition was associated with increasing temperature [hazard ratio (HR) per 1 °C: 1·13; 95% confidence interval (CI) 1·08–1·13], dew point (HR per 1 °C: 1·10, 95% CI 1·07–1·13), rainfall (HR per cm: 1·10, 95% CI 1·07–1·12), latitude (HR per 1 °C northing: 1·15, 95% CI 1·11–1·20), longitude (HR per 1 °C easting: 1·01, 95% CI 1·01–1·02) and elevation (HR per 100 m: 1·05, 95% CI 1·03–1·07). These results suggest that environmental factors may play a previously unrecognized role in the aetiology of initial Pa acquisition.
Intermetallic titanium aluminides solidifying via the disordered β-phase are of great interest for several high-temperature applications in automotive and aircraft industries. In this paper the thermocyclic oxidation behavior of three β-solidifying γ-TiAl-based alloys at 800°C and 900°C in air, with and without fluorine treatment, is reported for the first time. The behavior of the well-known TNM alloy (Ti-43.5Al-4Nb-1Mo-0.1B, in at.%) is compared with that of two Nb-free model alloys which contain different amounts of Mo (Ti-44Al-3Mo and Ti-44Al-7Mo, in at.%). During thermocyclic high-temperature exposure in air a mixed oxide scale develops on all three untreated alloys. Small additions of fluorine in the subsurface region of the alloys change the oxidation mechanism from mixed oxide scale formation to alumina at both temperatures. The oxidation resistance of the fluorine treated samples was significantly improved compared to the untreated samples.
Ensuring microstructural stability under technical relevant conditions is a determining criterion for the development of innovative high-temperature materials. In this work, the influ-ence of C and Si on the microstructural stability during creep exposure was investigated for a β-solidifying γ-TiAl based alloy with a nominal composition of Ti-43.5Al-4Nb-1Mo-0.1B (in at.%), named TNM. With a two-step heat treatment a microstructure consisting of fine lamellar α2/γ-colonies, surrounded by βo-phase and areas of discontinuous precipitation, starting from the boundaries of the lamellar colonies, was adjusted. Creep tests were carried out to examine the potential of C and Si to prevent microstructural instability during creep and hence improving the creep properties. At 815 °C the discontinuous precipitation process of the TNM alloy continues during ensuing creep testing leading to a reduced creep resistance. In comparison, the minimum creep rate of the TNM-0.3C-0.3Si alloy was significantly decreased caused by the lower βo-phase content and average lamellar spacing within the α2/γ-colonies, the precipitation of p-Ti3AlC carbides and the retarded kinetics of discontinuous precipitation.
The distribution of alloying elements in the constituent phases of a C-containing γ-TiAl based alloy has been characterized locally by atom probe tomography. The major elements of the alloy under consideration – Ti, Al, Nb, and Mo – are distributed uniformly within each of the constituent phases. Furthermore, Mo is preferentially dissolved in the βo-phase, whereas Nb content is similar in all phases. The selected C concentration of the alloy is below the overall solubility limit as no precipitates have been observed. Therefore, C is enriched in the α2-phase, whereas the βo-phase is depleted of C. In addition, βo/γ-interfaces have been prepared by site specific sample preparation and characterized by atom probe tomography. Segregation of Mo and C into the interfaces and their close vicinity was observed.
Although impaired recognition of affective facial expressions has been conclusively linked to antisocial behavior, little is known about the modifiability of this deficit. This study investigated whether and under which circumstances the proposed perceptual insensitivity can be addressed with a brief implicit training approach.
Facial affect recognition was assessed with an animated morph task, in which the participants (44 male incarcerated violent offenders and 43 matched controls) identified the onset of emotional expressions in animated morph clips that gradually changed from neutral to one of the six basic emotions. Half of the offenders were then implicitly trained to direct attention to salient face regions (attention training, AT) using a modified dot-probe task. The other half underwent the same protocol but the intensity level of the presented expressions was additionally manipulated over the course of training sessions (sensitivity to emotional expressions training, SEE training). Subsequently, participants were reassessed with the animated morph task.
Facial affect recognition was significantly impaired in violent offenders as compared with controls. Further, our results indicate that only the SEE training group exhibited a pronounced improvement in emotion recognition.
We demonstrated for the first time that perceptual insensitivity to facial affect can be addressed by an implicit training that directs attention to salient regions of a face and gradually decreases the intensity of the emotional expression. Future studies should focus on the potential of this intervention to effectively increase empathy and inhibit violent behavior in antisocial individuals.
After almost three decades of intensive fundamental research and development activities intermetallic titanium aluminides based on the -TiAl phase have found applications in automotive and aircraft engine industries. The advantages of this class of innovative high-temperature materials are their low density as well as their good strength and creep properties up to 750°C. A drawback, however, is their limited ductility at room temperature, which is reflected by a low plastic strain at fracture. This behavior can be attributed to a limited dislocation movement along with microstructural inhomogeneity. Advanced TiAl alloys, such as β-solidifying TNM™ alloys, are complex multi-phase materials which can be processed by ingot or powder metallurgy as well as precision casting methods. Each production process leads to specific microstructures which can be altered and optimized by thermo-mechanical processing and/or subsequent heat-treatments. The background of these heat-treatments is at least twofold, i.e. concurrent increase of ductility at room temperature and creep strength at elevated temperature. In order to achieve this goal the knowledge of the occurring solidification processes and phase transformation sequences is essential. Therefore, thermodynamic calculations were conducted to predict phase fraction diagrams of engineering TiAl alloys. After experimental verification, these phase diagrams provided the base for the development of heat treatments to adjust balanced mechanical properties. To determine the influence of deformation and kinetic aspects, sophisticated ex- and in-situ methods have been employed to investigate the evolution of the microstructure during thermo-mechanical processing and subsequent multi-step heat-treatments. For example, in-situ high-energy X-ray diffraction was conducted to study dynamic recovery and recrystallization processes during hot-deformation tests. Summarizing all results a consistent picture regarding microstructure formation and its impact on mechanical properties in TNM alloys can be given.
The CALPHAD (CALculation of PHAse Diagrams) method is widely recognized as a powerful tool in both scientific and industrial development of new materials and processes. For the implementation of consistent databases, where each phase is described separately, models are used which are based on physical principles and parameters assessed from experimental data. Such a database makes it possible to perform realistic calculations of thermodynamic properties of multi-component systems. However, a commercial available TiAl database can be applied for thermodynamic calculations to both conventional Ti-base alloys and complex intermetallic TiAl alloys to describe experimentally evaluated phase fractions as a function of temperature. In the present study calculations were done for a β-solidifying TiAl alloy with a nominal composition of Ti-43.5Al-4Nb-1Mo-0.1B (in at. %), termed TNMTM alloy. At room temperature this alloy consists of ordered γ-TiAl, α2-Ti3Al and β0-TiAl phases. At a certain temperature α2 and β0 disorder to α and β, respectively. Using the commercial database the thermodynamic calculations reflect only qualitative trends of phase fractions as a function of temperature. For more exact quantitative calculations the commercial available thermodynamic database had to be improved for TiAl alloys with high Nb (and Mo) contents, as recently reported for Nb-rich γ-TiAl alloys. Therefore, the database was modified by experimentally evaluated phase fractions obtained from quantitative microstructure analysis of light-optical and scanning electron micrographs as well as conventional X-ray diffraction after long-term heat treatments and by means of in-situ highenergy X-ray diffraction experiments. Based on the CALPHAD-conform thermodynamic assessment, the optimized database can now be used to correctly predict the phase equilibria of this multi-component alloying system, which is of interest for applications in automotive and aircraft engine industry.
The development of suitable hot-forming processes, e.g. forging, is an important step towards the serial production of TiAl parts. Several microstructure parameters change during hot-forming. However, the underlying mechanisms can normally only be inferred from post process metallographic studies.
We used a deformation dilatometer modified for working in the HZG synchrotron beamlines at DESY for hot-deformation experiments. This setup enables the in situ monitoring of the interaction and evolution of microstructure parameters during processing. We observed the evolution of phase fractions, grain size and crystallographic texture during deformation while simultaneously recording the process parameters, like temperature, force and length change.
Here we present the hot compressive deformation behaviour of a Ti-43Al-4Nb-1Mo-0.1B (in at.%) alloy. Several specimens were deformed at three temperatures each with two compression rates. During the experiments the Debye-Scherrer diffraction rings were continuously recorded.
In the last decades there was a growing interest in developing new light-weight intermetallic alloys, which are able to substitute the heavy superalloys at a certain temperature range. At present a new Ti-Al-Nb-Mo family, called TNM™ alloys, is being optimized to fulfill the challenging requirements. The aim of the present work was to study the microscopic mechanisms of defect mobility at high temperature in TNM alloys in order to contribute to the understanding of their influence on the mechanical properties and hence to promote the further optimization of these alloys. Mechanical spectroscopy has been used to study the internal friction and the dynamic modulus up to 1460 K of a TNM alloy under different thermal treatments. These measurements allow to follow the microstructural evolution during in-situ thermal treatments. A relaxation process has been observed at about 1050 K and was characterized as a function of temperature and frequency in order to obtain the activation parameters of the responsible mechanism. In particular, the activation enthalpy has been determined to be H= 3 eV. The results are discussed and an atomic mechanism is proposed to explain the observed relaxation process.
Intermetallic titanium aluminides are potential materials for application in high temperature components. In particular, alloys solidifying via the β-phase are of great interest because they possess a significant volume fraction of the disordered body-centered cubic β-phase at elevated temperatures ensuring good processing characteristics during hot-working. Nevertheless, their practical use at temperatures as high as 800°C requires improvements of the oxidation resistance. This paper reports on the fluorine effect on a multi-phase TiAl-alloy in the cast and hot-isostatically pressed condition at 800°C in air. The behavior of the so-called TNM material (Ti-43.5Al-4Nb-1Mo-0.1B, in at %) was compared with that of two other TiAl-alloys which are Nb-free and contain different amounts of Mo (3 and 7 at%, respectively). The oxidation resistance of the fluorine treated samples was significantly improved compared to the untreated samples. After fluorine treatment all alloys exhibit slow alumina kinetics indicating a positive fluorine effect. Results of isothermal and thermocyclic oxidation tests at 800°C in air are presented and discussed in the view of composition and microstructure of the TiAl-alloys investigated, along with the impact of the fluorine effect on the oxidation resistance of these materials.
A robust processing route at low cost is an essential requirement for high-temperature materials used in automotive engines. Because of their excellent high-temperature properties, their low density, high elastic modulus as well as high specific strength, intermetallic γ-TiAl based alloys are potential candidates for application in advanced automotive turbochargers. So-called 3rd generation alloys, such as TNM™ alloys with a nominal composition of Ti-43.5Al-4Nb-1Mo-0.1B (in at%), are multi-phase alloys consisting of γ-TiAl, α2-Ti3Al and a low volume fraction of βo-TiAl phase. In this paper a novel hot-processing route, which is a combination of a one-shot hot-forging step and a controlled cooling treatment, leads to mechanical properties required for turbocharger turbine wheels. The observed strength can be attributed to the small lamellar spacing within the α2/γ colonies of the nearly lamellar microstructure. In order to analyze the microstructure and the prevailing phase fractions microscopic examinations and X-ray diffraction measurements were conducted. The mechanical properties were determined by hardness measurements as well as tensile and creep tests. The evolution of the microstructure during the hot-forming process is described and its relation to the obtained mechanical properties.