71 research outputs found

    Liquid-jet target for laser-plasma soft x-ray generation

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    We describe a new liquid-target system for low-debris laser-plasma soft x-ray sources. The system is based on a microscopic liquid jet and is experimentally evaluated for 0.7-1 keV proximity lithography and water-window x-ray microscopy applications. Compared to an existing liquid-droplet target, this target system has the same low debris emission, high x-ray photon flux, and narrow spectral bandwidth. The advantages of the liquid-jet target include improved x-ray flux stability, increased range of suitable target liquids, and elimination of the need for temporal synchronization, thereby allowing less complex laser systems to be used. (C) 1996 American Institute of Physics

    Assessment Based Information Needs in Manual Assembly

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    To handle the complex and flexible manufacturing of today it is vital to have well functional information systems for the operators so that they know when, what and where to assemble. The current designs of assembly work instructions differ much between companies, but also between plants within the same company. The digitalization trends and initiatives such as Industry 4.0 show the manufacturing industry the advantages to incorporate new methods and tools into their businesses. Even though manufacturing IT systems are designed to be adaptive to product and volume changes, they are still widely characterized by their rigid structures. Making large changes to manufacturing IT systems with comprehensive structures is complex and requires large amounts of resources. Therefore, it is important for the manufacturing companies to make the correct investments. In previous studies, two current state analyses have been conducted with the aim to map manufacturing engineering processes and IT systems producing assembly work instructions in a mass customization context. This paper presents results from the third part of a longitudinal study which focuses on identifying operators’ information needs in manual assembly of heavy vehicles. This third study aims to identify the information gap between the current state and the wanted state by assessing information needs at 13 assembly stations in three plants belonging to a global production network. The purpose is to identify design requirements for future assembly information systems enabling the practical use of the digitalization

    Hard and transparent films formed by nanocellulose-TiO2 nanoparticle hybrids

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    T he formation of hybrids of nanofibrillated cellulose and titania nanoparticles in aqueous media has been studied. Their transparency and mechanical behavior have been assessed by spectrophotometry and nanoindentation. The results show that limiting the titania nanoparticle concentration below 16 vol% yields homogeneous hybrids with a very high Young's modulus and hardness, of up to 44 GPa and 3.4 GPa, respectively, and an optical transmittance above 80%. Electron microscopy shows that higher nanoparticle contents result in agglomeration and an inhomogeneous hybrid nanostructure with a concomitant reduction of hardness and optical transmittance. Infrared spectroscopy suggests that the nanostructure of the hybrids is controlled by electrostatic adsorption of the titania nanoparticles on the negatively charged nanocellulose surfaces

    Метод численно-аналитического расчета полей напряжений в системе "механический клиновидный нанодвойник - трещина" при поперечном сдвиге

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    Background Exercise-induced respiratory symptoms are common among adolescents. Exercise is a known stimulus for transient narrowing of the airways, such as exercise-induced bronchoconstriction (EIB) and exercise-induced laryngeal obstruction (EILO). Our aim was to investigate the prevalence of EIB and EILO in a general population of adolescents. Methods In this cross-sectional study, a questionnaire on exercise-induced dyspnoea was sent to all adolescents born in 1997 and 1998 in Uppsala, Sweden (n=3838). A random subsample of 146 adolescents (99 with self-reported exercise-induced dyspnoea and 47 without this condition) underwent standardised treadmill exercise tests for EIB and EILO. The exercise test for EIB was performed while breathing dry air; a positive test was defined as a decrease of &gt;= 10% in FEV1 from baseline. EILO was investigated using continuous laryngoscopy during exercise. Results The estimated prevalence of EIB and EILO in the total population was 19.2% and 5.7%, respectively. No gender differences were found. In adolescents with exercise-induced dyspnoea, 39.8% had EIB, 6% had EILO and 4.8% had both conditions. In this group, significantly more boys than girls had neither EIB nor EILO (64.7% vs 38.8%; p=0.026). There were no significant differences in body mass index, lung function, diagnosed asthma or medication between the participants with exercise-induced dyspnoea who had or did not have a positive EIB or EILO test result. Conclusions Both EIB and EILO are common causes of exercise-induced dyspnoea in adolescents. EILO is equally common among girls and boys and can coexist with EIB.Henrik Johansson and Katarina Norlander have shared first authorship on this paper.</p

    Clonal spread of carbapenem-resistant Klebsiella pneumoniae among patients at admission and discharge at a Vietnamese neonatal intensive care unit

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    Background The increasing prevalence of carbapenem-resistant Enterobacteriaceae (CRE) is a growing problem globally, particularly in low- to middle-income countries (LMICs). Previous studies have shown high rates of CRE colonisation among patients at hospitals in LMICs, with increased risk of hospital-acquired infections. Methods We isolated carbapenem-resistant Klebsiella pneumoniae (CRKP) from faecal samples collected in 2017 from patients at admission and discharge at a Vietnamese neonatal intensive care unit (NICU). 126 CRKP were whole-genome sequenced. The phylogenetic relationship between the isolates and between clinical CRKP isolates collected in 2012-2018 at the same hospital were investigated. Results NDM-type carbapenemase-(61%) and KPC-2-encoding genes (41%) were the most common carbapenem resistance genes observed among the admission and discharge isolates. Most isolates (56%) belonged to three distinct clonal clusters of ST15, carrying bla(KPC-2), bla(NDM-1) and bla(NDM-4), respectively. Each cluster also comprised clinical isolates from blood collected at the study hospital. The most dominant ST15 clone was shown to be related to isolates collected from the same hospital as far back as in 2012. Conclusions Highly resistant CRKP were found colonising admission and discharge patients at a Vietnamese NICU, emphasising the importance of continued monitoring. Whole-genome sequencing revealed a population of CRKP consisting mostly of ST15 isolates in three clonally related clusters, each related to blood isolates collected from the same hospital. Furthermore, clinical isolates collected from previous years (dating back to 2012) were shown to likely be clonally descended from ST15 isolates in the largest cluster, suggesting a successful hospital strain which can colonise inpatients

    Multilevel analysis of systolic blood pressure and ACE gene I/D polymorphism in 438 Swedish families – a public health perspective

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    BACKGROUND: Individuals belonging to the same family share a number of genetic as well as environmental circumstances that may condition a common SBP level. Among the genetic factors, the angiotensin converting enzyme (ACE) gene I/D polymorphism appears as a possible candidate as it might influence both SBP and the pharmacological effect of ACE inhibitors. We aimed to combine genetic epidemiology with public health ideas concerning life-course and multilevel epidemiology in order to understand the role of familial factors regarding individual SBP. METHODS: We applied multilevel regression analysis on 1926 individuals nested within 438 families from South Sweden. Modelling familial SBP variance as a function of age and use of ACE inhibitors we calculates a variance partition coefficient and the proportional change in familial SBP variance attributable to differences in ACE gene I/D polymorphism RESULTS: Our results suggest the existence of genetic or environmental circumstances that produce a considerable familial clustering of SBP, especially among individuals using ACE-inhibitors. However, ACE gene I/D polymorphism seems to play a minor role in this context. In addition, familial factors – genetic, environmental or their interaction – shape SBP among non-users of ACE inhibitors but their effect is expressed later in the life-course. CONCLUSION: Strategies directed to prevent hypertension should be launched in younger rather than in older ages and both prevention of hypertension and its treatment with ACE inhibitors should be focused on families rather than on individuals
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