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Improvement of environmental cleaning in hospitals has been shown to decrease in-hospital cross transmission of pathogens. Several objective methods, including aerobic colony counts (ACCs), the adenosine triphosphate (ATP) bioluminescence assay, and the fluorescent marker method have been developed to assess cleanliness. However, the standard interpretation of cleanliness using the fluorescent marker method remains uncertain.
To assess the fluorescent marker method as a tool for determining the effectiveness of hospital cleaning.
A prospective survey study.
An academic medical center.
The same 10 high-touch surfaces were tested after each terminal cleaning using (1) the fluorescent marker method, (2) the ATP assay, and (3) the ACC method. Using the fluorescent marker method under study, surfaces were classified as totally clean, partially clean, or not clean. The ACC method was used as the standard for comparison.
According to the fluorescent marker method, of the 830 high-touch surfaces, 321 surfaces (38.7%) were totally clean (TC group), 84 surfaces (10.1%) were partially clean (PC group), and 425 surfaces (51.2%) were not clean (NC group). The TC group had significantly lower ATP and ACC values (mean ± SD, 428.7 ± 1,180.0 relative light units [RLU] and 15.6 ± 77.3 colony forming units [CFU]/100 cm2) than the PC group (1,386.8 ± 2,434.0 RLU and 34.9 ± 87.2 CFU/100 cm2) and the NC group (1,132.9 ± 2,976.1 RLU and 46.8 ± 119.2 CFU/100 cm2).
The fluorescent marker method provided a simple, reliable, and real-time assessment of environmental cleaning in hospitals. Our results indicate that only a surface determined to be totally clean using the fluorescent marker method could be considered clean.
Evidence regarding the association between BMI and mortality in tuberculosis (TB) patients is limited and inconsistent. We investigated the impact of BMI on TB-specific and non-TB-specific mortality with respect to different timing of death. All Taiwanese adults with TB in Taipei were included in a retrospective cohort study in 2012–2014. Multinomial Cox proportional hazards regression was used to evaluate the associations between BMI, cause-specific mortality and timing of death. Of 2410 eligible patients, 86·0 % (2061) were successfully treated, and TB-specific and non-TB-specific mortality occurred for 2·2 % (54) and 13·9 % (335), respectively. After controlling for potential confounders, underweight was significantly associated with a higher risk of all-cause mortality (adjusted hazard ratio (AHR) 1·57; 95 % CI 1·26, 1·95), whereas overweight was not. When cause-specific death was considered, underweight was associated with an increased risk of either TB-specific (AHR 1·85; 95 % CI 1·03, 3·33) or non-TB-specific death (AHR 1·52; 95 % CI 1·19, 1·95) during treatment. With joint consideration of cause-specific and timing of death, underweight only significantly increased the risk of TB-specific (AHR 2·23; 95 % CI 1·09, 4·59) and non-TB-specific mortality (AHR 1·81; 95 % CI 1·29, 2·55) within the first 8 weeks of treatment. This study suggests that underweight increases the risk of early death in TB patients during treatment.
In situ and operando measurement techniques combined with nanoscale resolution have proven invaluable in multiple fields of study. We argue that evaluating device performance as well as material behavior by correlative X-ray microscopy with <100 nm resolution can radically change the approach for optimizing absorbers, interfaces and full devices in solar cell research. In this article, we thoroughly discuss the measurement technique of X-ray beam induced current and point out fundamental differences between measurements of wafer-based silicon and thin-film solar cells. Based on reports of the last years, we showcase the potential that X-ray microscopy measurements have in combination with in situ and operando approaches throughout the solar cell lifecycle: from the growth of individual layers to the performance under operating conditions and degradation mechanisms. Enabled by new developments in synchrotron beamlines, the combination of high spatial resolution with high brilliance and a safe working distance allows for the insertion of measurement equipment that can pave the way for a new class of experiments. Applied to photovoltaics research, we highlight today’s opportunities and challenges in the field of nanoscale X-ray microscopy, and give an outlook on future developments.
Autism spectrum disorder (ASD) is a highly heritable neurodevelopmental disorder, yet the search for definite genetic etiologies remains elusive. Delineating ASD endophenotypes can boost the statistical power to identify the genetic etiologies and pathophysiology of ASD. We aimed to test for endophenotypes of neuroanatomy and associated intrinsic functional connectivity (iFC) via contrasting male youth with ASD, their unaffected brothers and typically developing (TD) males.
The 94 participants (aged 9–19 years) – 20 male youth with ASD, 20 unaffected brothers and 54 TD males – received clinical assessments, and undertook structural and resting-state functional magnetic resonance imaging scans. Voxel-based morphometry was performed to obtain regional gray and white matter volumes. A seed-based approach, with seeds defined by the regions demonstrating atypical neuroanatomy shared by youth with ASD and unaffected brothers, was implemented to derive iFC. General linear models were used to compare brain structures and iFC among the three groups. Assessment of familiality was investigated by permutation tests for variance of the within-family pair difference.
We found that atypical gray matter volume in the mid-cingulate cortex was shared between male youth with ASD and their unaffected brothers as compared with TD males. Moreover, reduced iFC between the mid-cingulate cortex and the right inferior frontal gyrus, and increased iFC between the mid-cingulate cortex and bilateral middle occipital gyrus were the shared features of male ASD youth and unaffected brothers.
Atypical neuroanatomy and iFC surrounding the mid-cingulate cortex may be a potential endophenotypic marker for ASD in males.
This study investigates the effect of outside director experience on the performance of a firm's joint venture (JV) engagements, a type of strategic move where the influence of board remains under-investigated despite directors’ active participation in the decision-making process. By examining the direct linkage between director experience and strategic performance, our research presents the first direct evidence of the value outside director experience has for a firm's strategic engagements; this has previously been exclusively assessed by indirect indicators. We address this important issue in the following three ways. First, we explore what type of director experience contributes most to JV outcomes. Second, we investigate what circumstantial factors significantly influence the value of director experience. Lastly, we analyze whether incentive mechanisms moderate the relationship between director experience and firm performance. The results confirm the value of director experience gained from JV engagements but not from relevant industries. In addition, executive experience and the industry affiliation of the JV significantly moderate the value of director experience. Finally, experienced directors with large shareholdings outperform those with experience but limited stakes in the firms’ equity, justifying the necessity to motivate directors’ governance efforts despite their existing fiduciary obligation to shareholders. Our study contributes to agency theory by indicating that director experience holds a significant influence on a firm's strategic performance, an issue which has long been neglected in agency-based governance research. It also contributes to resource-dependence theory by providing a direct measurement of directors’ experiential assets, which have so far been exclusively assessed by indirect indicators. Finally, findings from this study can elucidate the long-standing question of how a firm can realize the purported benefits JVs provide by introducing a vital yet rarely explored factor: board experience.
In this paper we introduce a novel, flexible, system for mechanical deformation detection. The core of the system is based on an Organic Thin Film Transistor (OTFT) which has been assembled on a flexible PET substrate and patterned by means of inkjet printing. OTFT-based mechanical sensors were fabricated employing two different organic semiconductors, namely a small molecule (pentacene) deposited by thermal evaporation and its solution-processable derivative 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) deposited by drop casting. It will be shown that the surface deformation induced by an external mechanical stimulus gives rise in both cases to a marked, reproducible and reversible (within a certain rage of surface deformation) variation of the device output current. Starting from these results, more complex structures such as arrays and matrices of OTFT-based mechanical sensors have been fabricated by means of inkjet printing. Thanks to the flexibility of the introduced structure, we will show that the presented system can be transferred on different surfaces (hard and soft) and employed for a wide range of applications. In particular, we have designed and fabricated a fully functional system based on a matrix of 64 elements that can be employed for detecting mechanical stimuli over larger areas, and will demonstrate that such a system can be successfully employed for tactile transduction in the realization of artificial “robot skins”.
The prevalence and genotype distribution of human papillomavirus (HPV) infection in women with normal cervical cytology varies widely according to the population studied. Two non-overlapping population-based cohort studies of women aged ⩾30 years for the periods 2008–2009 (n=5026) and 2004–2005 (n=10 014) were analysed. The prevalence rate of HPV was 11·0% (95% CI 10·5–11·6). HPV infection was significantly associated with age, menopausal status, and inversely associated with hormone replacement therapy. There was an increasing trend of α3/α15, α5/α6, and multiple HPV infections with increasing age. The five most common types were HPV52, 18, 53, 58 and 70, while HPV16, 31, 33 ranked 21st, 25th, and 16th, respectively, in the merged cohort with normal cytology (n=14 724). HPV16, 31, and 33 were significantly associated with abnormal cytology, which could have resulted in their rarity in the total merged cohort (n=15 040).
In this paper, we report the characterization of vertically aligned ZnO nanowire (NW) arrays synthesized by metal-catalyzed chemical vapor deposition. The growth mechanism of ZnO NWs may be related to vapor-solid-nucleation. Morphological, structural, optical and field emission characteristics can be modified by varying the growth time. For growth time reaches 120 min, the length and the diameter of ZnO NWs are 1.5 μm and 350 nm, and they also show preferential growth orientation along the c-axis. Moreover, strong alignment and uniform distribution of ZnO NWs can effectively enhance the antireflection to reach the average reflectance of 5.7% in the visible region as well. Field emission measurement indicated that the growth time play an important role in density- and morphology-controlled ZnO NWs, and thus ZnO NWs are expected to be used in versatile optoelectronic devices.
A review is given on insulators (oxides and nitrides) which have been deposited on GaN to form metal-insulator (oxides and nitrides)-semiconductor (MOS or MIS) diodes with a low interfacial density of states (Dit). These insulators include AlN, SiO2, Si3N4, SiO2/Ga2O3, and Ga2O3(Gd2O3). Techniques for depositing these insulators and methods for cleaning GaN surfaces prior to the insulator deposition are discussed. Recent progress on GaN MOSFET's (with SiO2/Ga2O3, and Ga2O3(Gd2O3) as gate dielectrics) and MISFET's (with AlN as a gate dielectric) is also reviewed. When exposed to room air, GaN surface is not as robust as previously thought. Therefore, preparation of a clean GaN surface for deposition of oxides and nitrides is necessary to achieve a low Dit. By heating GaN samples in UHV to clean the surfaces followed by deposition of Ga2O3(Gd2O3) and SiO2, we have achieved a low Dit with negligible hysteretic loops in the capacitance-voltage curves
Quantification of very low density molecular coatings on large (60 nm) gold nanoparticles (AuNPs) is demonstrated via the use of antibody-mediated self-limiting self-assembly of small and large AuNPs into raspberry-like structures subsequently imaged by atomic force microscopy (AFM). AFM imaging is proposed as an automated, lower-cost, higher-throughput alternative to immunostaining and imaging by transmission electron microscopy. Synthesis of large AuNPs, containing one of three ligand molecules in one of three stoichiometries (1, 2, or 10 ligands per AuNP), and small probe AuNPs with one of three antibody molecules in a one antibody per AuNP ratio, enabled a range of predicted self-limiting self-assembled structures. A model predicting the probability of observing a given small to large AuNP ratio based on a topography measurement such as AFM is described, in which random orientational deposition is assumed and which accounts for the stochastic synthesis method of the library AuNPs with varied ligand ratios. Experimental data were found to agree very well with the predictive models when using an established AFM sample preparation method that avoids drying-induced aggregation.
The corrosion behavior of a Ni3A1–1 5at%Fe alloy has been studied in air and melted salts, and also that of Ni3Al alloys contained series boron in melted salts. The first alloy has two oxidation rate constants. Its initial oxidation activity energy is 319 kJ / mol. There was much FeAl2O4 formed at 950°C, which possessed better oxidation resistance than NiFe2O4, therefore the alloy had the best oxidation resistance at 950°C. It also had better sulfidation resistance than 00Cr19NillTi stainless steel at 850°C, but the alloy was sulfidized seriously at 950°C. The sulfides were FeS2 at 850°C and A12S3, Ni2S3 at 950°C. There were different initial oxides formed, which were Fe3O4 at 850°C, and mixture oxides of NiO, NiMoO4, A12O3 and NiAl2O4 at 950°C , respectively. The Ni3Al alloys with boron contents from 0 to 3.7at% had better sulfidation resistance than the stainless steel at 850°C, and the alloy with 1.37at%B was the best. The sulfides were the same in the boron containing Ni3Al alloys which were Al2S3 and Ni7S6.
The microstructure and mechanical properties of Ni3Al-based composites reinforced with TiC particles have been investigated. The composites, which contained 2, 6, 10 vol.%TiC particulate reinforcement, were fabricated by solidification processing method. The matrix alloy selected for this study was the advanced nickel-aluminide (Ni-16Al-8Cr-1Zr-0.8Mo-0.04B at.%).The optical micrographs revealed that the carbides in the composites distributed uniformly in the martix and appeared as fairly equiaxed particles. SEM observation showed that the interface between TiC and matrix is quite smooth, sharp and free of any phase. The test results indicated that the hardness was increased with increasing volume fraction of TiC particles at ambient temperature, and the composites exhibited higher hardness after 1100°C × 8h heat treatment. The yield strength has been improved due to reinforcement by the TiC particles at ambient and elevated temperature, but their ductility was reduced obviously. From SEM fractography, it could be seen that tensile failure occurred at the matrix / particulate interface.
The formation of porous silicon (PS) from n/p, n+/p and p+/n structures carried from polycrystalline silicon films (poly-Si) deposited on single crystal silicon (c-Si) substrates was studied by cross-sectional transmission electron microscopy. Our results clearly show that the pore formation in such structures involve the extended defects of the poly-Si film. The role played by these defects depends on the doping type and level, and on whether the anodization is performed under illumination or not.
Single crystal Gd2O3 dielectric thin films were epitaxially grown on GaAs. The Gd2O3 film has a cubic structure isomorphic to Mn2O3, and is (110) oriented in single domain on the (100) GaAs surface. The oxide film has low leakage current densities ˜ 10–9 – 10–10 A/cmT2 at zero bias. Typical breakdown field is 4 MV/cm for an oxide film 185 Å thick, and >10 MV/cm for an oxide less than 50 Å thick. Both accumulation and inversion layers were observed in the Gd2O3-GaAs metal oxide semiconductor (MOS) diodes using capacitance-voltage (C-V) measurements, with an interfacial density of states around 1011 cm–2 eV–1.
The transfer of strain between thin film features and the underlying substrate represents an important factor in the performance and reliability of semiconductor devices, particularly as the distances between these structures decrease. In order to characterize the interaction regions produced in the substrate due to strained thin film structures, we employed synchrotron-based x-ray diffraction techniques to map the enhanced diffracted intensity of the single-crystal Si substrate at sub-micron resolution. The dynamic-to-kinematic transition observed in the scattering of x-rays from deformed crystals makes this technique extremely sensitive to the amount of substrate deformation as a function of position. Measurements were conducted on 1 μm thick Ni dots evaporated onto Si (111) substrates and 0.24 μm thick, heteroepitaxially grown SiGe strips of various widths on Si (001). The interaction field resolved by the enhanced Si diffracted intensity in the substrate extended up to 100 times the thickness of these features. Although the boundary of the interaction field varied as a function of feature width, a characteristic curve was generated to describe the decay rate of enhanced Si diffracted intensity when the distance from the feature edge is normalized by a mean interaction distance (MID). The rate of decay of the strain fields predicted by traditional treatments of the mechanical interaction between the thin film and substrate did not correspond to the measured decay rates.
Highy-quality nano-structured ZnO samples have been synthesized by simple chemical solution and post-thermal treatment. The samples were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), temperature-dependent photoluminescence (PL) spectra measurements. XRD patterns illustrated that there were no second phases in these ZnO samples, and the TEM results indicated that the ZnO samples are single crystalline with a hexagonal structure. Room-temperature PL spectra of ZnO thin films showed a strong UV near-band-edge (NBE) emission located at about 390 nm and a green defect-related (G) emissions, where the intensity ratio (INBE/IG) varies with the annealing temperatures. Meanwhile, the ZnO samples exhibited free exciton and very sharp exciton emissions at low temperatures. Particularly, room-temperature UV random lasing characteristic of ZnO films has been observed as well. It is shown that these nano-structured ZnO samples can exhibit random laser action depending on the growth condition. The threshold intensity for the lasing is comparable to earlier reported data. These results indicate that nano-structured ZnO samples prepared by simple techniques may be a promising material for further photonic devices. Possible lasing mechanism is discussed and further investigation to clarify the mechanism between the nano-structured ZnO samples is still underway.