| 1. |
- Beck-Friis, Thomas, et al.
(författare)
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Burden of rotavirus infection in hospitalized elderly individuals prior to the introduction of rotavirus vaccination in Sweden
- 2019
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Ingår i: Journal of Clinical Virology. - : Elsevier BV. - 1386-6532. ; 119, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- Background: Rotavirus gastroenteritis (GE) in the elderly has been much less studied than in children. Objectives: The aim of this study was to determine the morbidity and mortality for elderly hospitalized patients with rotavirus GE prior to the introduction of rotavirus vaccination in Sweden, and to investigate the epidemiology of rotavirus genotypes in these patients. Study design: All patients 60 years or older who were hospitalized at Sahlgrenska University Hospital, Gothenburg, Sweden, and were rotavirus positive in a clinical diagnostic test from 2009 to 2016, were included. Medical records were reviewed and rotavirus genotyping real-time PCR was performed. Results: One hundred and fifty-nine patients were included, corresponding to an annual incidence of hospitalization due to rotavirus GE of 16/100 000 inhabitants aged 60 years or older. G2P[4] was the most common genotype, followed by G1P[8] and G4P[8]. The majority of patients had community-onset of symptoms and no or few pre-existing health disorders. Four patients (2.5%) died within 30 days of sampling. Patients with hospital-onset rotavirus GE had a longer median length of stay following diagnosis compared with patients with community-onset of symptoms (19 vs. 5 days, p = 0.001) and higher 30-day mortality (8.6% (3/35) vs. < 1% (1/124), p = 0.03). Conclusions: Hospitalization due to rotavirus GE among the elderly seems to mainly affect otherwise healthy individuals and is associated with low 30-day mortality.
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| 2. |
- Sundell, Nicklas, et al.
(författare)
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Measles outbreak in Gothenburg urban area, Sweden, 2017 to 2018: low viral load in breakthrough infections
- 2019
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Ingår i: Eurosurveillance. - 1560-7917. ; 24:17, s. 2-12
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Tidskriftsartikel (refereegranskat)abstract
- In an outbreak of measles in Gothenburg, Sweden, breakthrough infections (i.e. infections in individuals with a history of vaccination) were common. The objective of this study was to compare measles RNA levels between naive (i.e. primary) and breakthrough infections. We also propose a fast provisional classification of breakthrough infections. Medical records were reviewed and real-time PCR-positive samples geno-typed. Cases were classified as naive, break-through or vaccine infections. We compared clinical symptoms and measles RNA cycle threshold (Ct) values between breakthrough and naive infections. Sixteen of 28 confirmed cases of measles in this outbreak were breakthrough infections. A fast provisional classification, based on previous history of measles vaccination and detectable levels of measles IgG in acute serum, correctly identified 14 of the 16 breakthrough infections, confirmed by IgG avidity testing. Measles viral load was significantly lower in nasopharyngeal samples from individuals with breakthrough compared with naive infections (median Ct-values: 32 and 19, respectively, p < 0.0001). No onward transmission from break-through infections was identified. Our results indicate that a high risk of onward transmission is limited to naive infections. We propose a fast provisional classification of breakthrough measles that can guide contact tracing in outbreak settings.
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| 3. |
- Sundell, Nicklas, et al.
(författare)
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PCR detection of respiratory pathogens in asymptomatic and symptomatic adults.
- 2019
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Ingår i: Journal of clinical microbiology. - 1098-660X. ; 57:1
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Tidskriftsartikel (refereegranskat)abstract
- The frequency of viral respiratory pathogens in asymptomatic subjects is poorly defined. The aim of this study was to explore the prevalence of respiratory pathogens in the upper airways of asymptomatic adults, as compared with a reference population of symptomatic patients sampled in the same centres during the same period. Nasopharyngeal (NP) swab samples were prospectively collected from adults with and without ongoing symptoms of respiratory tract infection (RTI) during 12 consecutive months, in primary care centres as well as hospital emergency departments, and analysed for respiratory pathogens by a PCR panel detecting 16 viruses and four bacteria. Altogether, 444 asymptomatic and 75 symptomatic subjects completed sampling as well as follow-up (FU) at day 7. In the asymptomatic subjects the detection rate of viruses was low (4.3%) and the most common virus detected was rhinovirus (3.2%). Streptococcus pneumoniae was found in 5.6% of the asymptomatic subjects and Haemophilus influenzae in 1.4%. The only factor independently associated with low viral detection rate in asymptomatic subjects was age ≥65 (p=0.04). An increased detection rate of bacteria was seen in asymptomatic subjects who were currently smoking (p<0.01) and who had any chronical condition (p<0.01). We conclude that detection of respiratory viruses in asymptomatic adults is uncommon, suggesting that a positive PCR result from a symptomatic patient likely is relevant for ongoing respiratory symptoms. Age influences the likelihood of virus detection among asymptomatic adults and smoking as well as co-morbidity may increase the prevalence of bacterial pathogens in the upper airways.
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| 4. |
- Andersson, Urban, 1965, et al.
(författare)
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Research.chalmers.se : building the next generation research information infrastructure at Chalmers University of Technology
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- research.chalmers.se is the new research infrastructure - repository platform and CRIS - that is currently being developed by the library at Chalmers University of Technology, Sweden.With the aim of eventually becoming the place for all relevant research information at the university, and built in accordance with the principles of UX (User eXperience) and agile development (SCRUM) and with a steady focus on value and continuous deliveries, research.chalmers.se is set to replace most of the current research information infrastructure at the university. It will provide new services for collecting, curating and providing quality data, as well as tools for analysis, sharing and promotion of research output by new and up-to-date means.research.chalmers.se is (or will be)- creating and preserving values - research output and data repository with qualitativedata, researcher profiles, open access.- promoting open access publishing, by proving the value of knowledge sharing, visibilityand impact as a researcher.- collecting and curating all kinds of research information, including publications,research data and information about research projects and other research activities.- built with responsive design that is adapted to current user needs. - using current standards for validity and sustainability, such as ORCID, DOI andFundRef IDs.- providing new ways of exploring and analyzing data, such as altmetrics, open APIs andvisualization tools.In the first phase (starting in 2014) a complete system for handling research project and grant information has been developed, together with integration of the local HR system for persistent and structured data about staff and organisation.In the current phase (2016-) repository services are being developed, such as a new publication database and a new digital repository, along with services for sharing and collecting data.The next phase(s) will include handling of research data, research activities, learning objects and tools for bibliometric analysis.This poster will show some of the current and future features and the principles of UX and agile development, as well as the experiences of moving out of the comfort zone and dealing with new, non-publication related data, while sustaining and enhancing existing data and current services. It will discuss the challenges and possible solutions, when handling different kinds of research information for use and re-use, in the long run enabling the comprehension of the big picture of research at Chalmers University of Technology.
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| 5. |
- Bjarnason, A., et al.
(författare)
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Incidence, etiology, and outcomes of community-acquired pneumonia: A population-based study
- 2018
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Ingår i: Open Forum Infectious Diseases. - : Oxford University Press (OUP). - 2328-8957. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- Background. The microbial etiology of community-acquired pneumonia (CAP) is often unclear in clinical practice, and previous studies have produced variable results. Population-based studies examining etiology and incidence are lacking. This study examined the incidence and etiology of CAP requiring hospitalization in a population-based cohort as well as risk factors and outcomes for specific etiologies. Methods. Consecutive admissions due to CAP in Reykjavik, Iceland were studied. Etiologic testing was performed with cultures, urine-antigen detection, and polymerase chain reaction analysis of airway samples. Outcomes were length of stay, intensive care unit admission, assisted ventilation, and mortality. Results. The inclusion rate was 95%. The incidence of CAP requiring hospitalization was 20.6 cases per 10 000 adults/year. A potential pathogen was detected in 52% (164 of 310) of admissions and in 74% (43 of 58) with complete sample sets. Streptococcus pneumoniae was the most common pathogen (61 of 310, 20%; incidence: 4.1/10 000). Viruses were identified in 15% (47 of 310; incidence: 3.1/10 000), Mycoplasma pneumoniae were identified in 12% (36 of 310; incidence: 2.4/10 000), and multiple pathogens were identified in 10% (30 of 310; incidence: 2.0/10 000). Recent antimicrobial therapy was associated with increased detection of M pneumoniae (P ≤ .001), whereas a lack of recent antimicrobial therapy was associated with increased detection of S pneumoniae (P = .02). Symptoms and outcomes were similar irrespective of microbial etiology. Conclusions. Pneumococci, M pneumoniae, and viruses are the most common pathogens associated with CAP requiring hospital admission, and they all have a similar incidence that increases with age. Symptoms do not correlate with specific agents, and outcomes are similar irrespective of pathogens identified. © The Author(s) 2018.
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| 6. |
- Bjarnason, A, et al.
(författare)
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Utility of oropharyngeal real-time PCR for S. pneumoniae and H. influenzae for diagnosis of pneumonia in adults.
- 2017
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Ingår i: European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology. - : Springer Science and Business Media LLC. - 1435-4373. ; 36:3, s. 529-536
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Tidskriftsartikel (refereegranskat)abstract
- A lack of sensitive tests and difficulties obtaining representative samples contribute to the challenge in identifying etiology in pneumonia. Upper respiratory tract swabs can be easily collected and analyzed with real-time PCR (rtPCR). Common pathogens such as S. pneumoniae and H. influenzae can both colonize and infect the respiratory tract, complicating the interpretation of positive results. Oropharyngeal swabs were collected (n=239) prospectively from adults admitted to hospital with pneumonia. Analysis with rtPCR targeting S. pneumoniae and H. influenzae was performed and results compared with sputum cultures, blood cultures, and urine antigen testing for S. pneumoniae. Different Ct cutoff values were applied to positive tests to discern colonization from infection. Comparing rtPCR with conventional testing for S. pneumoniae in patients with all tests available (n=57) resulted in: sensitivity 87%, specificity 79%, PPV 59% and NPV 94%, and for H. influenzae (n=67): sensitivity 75%, specificity 80%, PPV 45% and NPV 94%. When patients with prior antimicrobial exposure were excluded sensitivity improved: 92% for S. pneumoniae and 80% for H. influenzae. Receiver operating characteristic curve analysis demonstrated for S. pneumoniae: AUC=0.65 (95% CI 0.51-0.80) and for H. influenzae: AUC=0.86 (95% CI 0.72-1.00). Analysis of oropharyngeal swabs using rtPCR proved both reasonably sensitive and specific for diagnosing pneumonia caused by S. pneumoniae and H. influenzae. This method may be a useful diagnostic adjunct to other methods and of special value in patients unable to provide representative lower airway samples.
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| 7. |
- Broering Chaar, Ana Beatriz, 1990-, et al.
(författare)
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The Effect of Cathodic Arc Guiding Magnetic Field on the Growth of (Ti0.36Al0.64)N Coatings
- 2019
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Ingår i: Coatings. - : MDPI. - 2079-6412. ; 9:10
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Tidskriftsartikel (refereegranskat)abstract
- We use a modified cathodic arc deposition technique, including an electromagnetic coil that introduces a magnetic field in the vicinity of the source, to study its influence on the growth of (Ti0.36Al0.64)N coatings. By increasing the strength of the magnetic field produced by the coil, the cathode arc spots are steered toward the edge of the cathode, and the electrons are guided to an annular anode surrounding the cathode. As a result, the plasma density between the cathode and substrate decreased, which was observed as a lateral spread of the plasma plume, and a reduction of the deposition rate. Optical emission spectroscopy shows reduced intensities of all recorded plasma species when the magnetic field is increased due to a lower number of collisions resulting in excitation. We note a charge-to-mass ratio decrease of 12% when the magnetic field is increased, which is likely caused by a reduced degree of gas phase ionization, mainly through a decrease in N2 ionization. (Ti0.36Al0.64)N coatings grown at different plasma densities show considerable variations in grain size and phase composition. Two growth modes were identified, resulting in coatings with (i) a fine-grained glassy cubic and wurtzite phase mixture when deposited with a weak magnetic field, and (ii) a coarse-grained columnar cubic phase with a strong magnetic field. The latter conditions result in lower energy flux to the coating’s growth front, which suppresses surface diffusion and favors the formation of c-(Ti,Al)N solid solutions over phase segregated c-TiN and w-AlN.
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| 8. |
- Chen, Yu-Hsiang, et al.
(författare)
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Enhanced thermal stability and fracture toughness of TiAlN coatings by Cr, Nb and V-alloying
- 2018
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Ingår i: Surface & Coatings Technology. - : Elsevier. - 0257-8972 .- 1879-3347. ; 342, s. 85-93
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Tidskriftsartikel (refereegranskat)abstract
- The effect of metal alloying on mechanical properties including hardness and fracture toughness were investigated in three alloys, Ti 0.33Al0.50(Me) 0.17N (Me = Cr, Nb and V), and compared to Ti0.50Al0.50N, in the as-deposited state and after annealing. All studied alloys display similar as-deposited hardness while the hardness evolution during annealing is found to be connected to phase transformations, related to the alloy’s thermal stability. The most pronounced hardening was observed in Ti0.50Al0.50N, while all the coatings with additional metal elements sustain their hardness better and they are harder than Ti0.50Al0.50N after annealing at 1100 °C. Fracture toughness properties were extracted from scratch tests. In all tested conditions, as-deposited and annealed at 900 and 1100 °C, Ti0.33Al0.50Nb0.17N show the least surface and sub-surface damage when scratched despite the differences in decomposition behavior and h-AlN formation. Theoretically estimated ductility of phases existing in the coatings correlates well with their crack resistance. In summary, Ti0.33Al0.50Nb0.17N is the toughest alloy in both as-deposited and post-annealed states.
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| 9. |
- Gustavsson, Lars, et al.
(författare)
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Low serum levels of CCL5 are associated with longer duration of viral shedding in norovirus infection
- 2015
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Ingår i: Journal of Clinical Virology. - : Elsevier BV. - 1386-6532. ; 69, s. 133-137
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Tidskriftsartikel (refereegranskat)abstract
- Background: The mechanisms that determine the duration of fecal shedding of norovirus in humans have not been described in detail. Objectives: We investigated serum inflammatory mediator levels in relation to the duration of viral shedding in norovirus infection. Study design: A prospective cohort study of patients hospitalized with acute norovirus genogroup II infection. Rectal swab samples were obtained at inclusion and day 7, 14, 21 and 28. Serum levels of 42 inflammatory mediators were determined with a Luminex-based cytokine assay. Sera from 20 healthy blood donors served as controls. Results: Altogether, 28 patients (54% women, median age 83 years, median duration of symptoms 3 days) were included. Twelve subjects cleared the virus within 14 days and 16 were norovirus-RNA positive for >21 days, constituting the two study groups ("rapid" vs. "slow" clearance). Individuals with norovirus infection had higher levels of IL-18, CXCL9, CXCL10, soluble IL-2 receptor and macrophage migration inhibitory factor (MIF), compared to controls (p < 0.05), with the highest median concentrations in the slow clearance group. In contrast, CCL5 levels were lower in the slow compared to the rapid clearance group (median 54 vs. 134 ng/mL, p < 0.05), and lower in norovirus-infected patients than in controls. Conclusion: Low levels of CCL5 were associated with longer duration of viral shedding, suggesting that CCL5 may influence the clearance of norovirus. (C) 2015 Elsevier B.V. All rights reserved.
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| 10. |
- Gustavsson, Lars, et al.
(författare)
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Slow Clearance of Norovirus following Infection with Emerging Variants of Genotype GII.4 Strains.
- 2017
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Ingår i: Journal of clinical microbiology. - 1098-660X. ; 55:5, s. 1533-1539
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Tidskriftsartikel (refereegranskat)abstract
- The emergence of new norovirus genotype GII.4 strains is associated with widespread norovirus epidemics. Extended periods of viral shedding can contribute to the epidemic potential of norovirus. To describe the duration of viral shedding in infections with novel emerging GII.4 strains versus infections with previously circulating strains, we performed a prospective cohort study of patients hospitalized with norovirus gastroenteritis during separate winter seasons. Rectal swab samples were obtained at the time of inclusion and weekly during follow-ups. The subgenotype strain was determined from capsid sequences. The outcome was defined by the detection of virus for >14 days (slow clearance) or by the detection of negative samples within 14 days (rapid clearance). Two major epidemic GII.4 strains emerged during the study period, GII.4 New Orleans 2009, in 2010, and GII.4 Sydney 2012, in 2012. From these two seasons, sequences were available from 24 cases where the duration of shedding could be determined. The median age of the patients was 83 years and 50% were women. The majority of patients were infected with virus that clustered with the respective season's epidemic strain (n = 19), whereas 5 patients had previously circulating strains (3 were Den Haag 2006b, in 2010, and 2 were New Orleans 2009, in 2012). Among the patients infected with an epidemic strain, the proportion who shed virus for >14 days was significantly higher (16/19 [84%] versus 1/5 [20%], P = 0.01). In summary, a slow clearance of norovirus from stool was more common in infections with novel epidemic GII.4 strains. This suggests that the average duration of shedding may be longer during seasons when new GII.4 strains have emerged.
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| 11. |
- Hansen, Karin B., et al.
(författare)
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Flocked nasal swab versus nasopharyngeal aspirate in adult emergency room patients: similar multiplex PCR respiratory pathogen results and patient discomfort
- 2016
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Ingår i: Infectious Diseases. - : Informa UK Limited. - 2374-4235 .- 2374-4243. ; 48:3, s. 246-250
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Tidskriftsartikel (refereegranskat)abstract
- Fifty adult emergency room patients with symptoms of respiratory tract infections or acute onset of extreme fatigue were sampled by both nasopharyngeal aspirate (NPA) and flocked nasal swab (fNS). Respiratory agents were detected by a qualitative influenza PCR and an 18-valent multiplex PCR in 20 of 29 patients with a clinical diagnosis of respiratory tract infection, and in 3 of 21 without such a diagnosis. PCR detected influenza A and B in NPA samples from 11 patients and in fNS samples from 10 patients. Little or no discomfort was perceived by 60% of the patients when sampled by NPA and by 66% when sampled by fNS. We conclude that NPA and fNS were equally sensitive for detection of respiratory agents by multiplex PCR, and the two sampling methods did not differ significantly regarding discomfort perceived by patients (p=0.171, Wilcoxon signed rank test). Hence less invasive sampling by fNS might be preferable in certain settings and situations.
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| 12. |
- Magnusson, Jesper, et al.
(författare)
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Viral Respiratory Tract Infection During the First Postoperative Year Is a Risk Factor for Chronic Rejection After Lung Transplantation
- 2018
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Ingår i: Transplantation Direct. - : Ovid Technologies (Wolters Kluwer Health). - 2373-8731. ; 4:8
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Tidskriftsartikel (refereegranskat)abstract
- Background. Chronic lung allograft dysfunction (CLAD) is the major limiting factor for long-term survival in lung transplant recipients. Viral respiratory tract infection (VRTI) has been previously associated with CLAD development. The main purpose of this study was to evaluate the long-term effects of VRTI during the first year after lung transplantation in relation to CLAD development. Method. Ninety-eight patients undergoing lung transplantation were prospectively enrolled between 2009 and 2012. They were monitored for infections with predefined intervals and on extra visits during the first year, the total follow-up period ranged between 5 and 8 years. Nasopharyngeal swab and bronchoalveolar lavage samples were analyzed using a multiplex polymerase chain reaction panel for respiratory pathogens. Data regarding clinical characteristics and infectious events were recorded. Results. Viral respiratory tract infection during the first year was identified as a risk factor for long-term CLAD development (P = 0.041, hazard ratio 1.94 [1.03-3.66]) in a time-dependent multivariate Cox regression analysis. We also found that coronavirus in particular was associated with increased risk for CLAD development. Other identified risk factors were acute rejection and cyclosporine treatment. Conclusions. This study suggests that VRTI during the first year after lung transplantation is associated with long-term CLAD development and that coronavirus infections in particular might be a risk factor.
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| 13. |
- Nordén, Rickard, 1977, et al.
(författare)
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Quantification of torque teno virus and Epstein-Barr virus is of limited value for predicting the net state of immunosuppression after lung transplantation
- 2018
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Ingår i: Open Forum Infectious Diseases. - : Oxford University Press (OUP). - 2328-8957. ; 5:4
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Tidskriftsartikel (refereegranskat)abstract
- Background. Major hurdles for survival after lung transplantation are rejections and infectious complications. Adequate methods for monitoring immune suppression status are lacking. Here, we evaluated quantification of torque teno virus (TTV) and Epstein-Barr virus (EBV) as biomarkers for defining the net state of immunosuppression in lung-transplanted patients. Methods. This prospective single-center study included 98 patients followed for 2 years after transplantation. Bacterial infections, fungal infections, viral respiratory infections (VRTI), cytomegalovirus (CMV) viremia, and acute rejections, as well as TTV and EBV levels, were monitored. Results. The levels of torque teno virus DNA increased rapidly after transplantation, likely due to immunosuppressive treatment. A modest increase in levels of Epstein-Barr virus DNA was also observed after transplantation. There were no associations between either TTV or EBV and infectious events or acute rejection, respectively, during follow-up. When Tacrolimus was the main immunosuppressive treatment, TTV DNA levels were significantly elevated 6-24 months after transplantation as compared with Cyclosporine treatment. Conclusions. Although replication of TTV, but not EBV, appears to reflect the functionality of the immune system, depending on the type of immunosuppressive treatment, quantification of TTV or EBV as biomarkers has limited potential for defining the net state of immune suppression.
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| 14. |
- Sundell, Nicklas, et al.
(författare)
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A four year seasonal survey of the relationship between outdoor climate and epidemiology of viral respiratory tract infections in a temperate climate
- 2016
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Ingår i: Journal of Clinical Virology. - : Elsevier BV. - 1386-6532. ; 84, s. 59-63
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Tidskriftsartikel (refereegranskat)abstract
- Background The relation between weather conditions, viral transmission and seasonal activity of respiratory viruses is not fully understood. Objectives To investigate the impact of outdoor weather in a temperate climate setting on the seasonal epidemiology of viruses causing respiratory tract infections, particularly influenza A (IFA). Study design In total, 20,062 clinical nasopharyngeal swab samples referred for detection of respiratory pathogens using a multiplex PCR panel, between October 2010 and July 2013, were included. Results of PCR detection were compared with local meteorological data for the same period. Results Low temperature and vapor pressure (VP) were associated with weekly incidence of IFA, respiratory syncytial virus, metapneumovirus, bocavirus and adenovirus but no association with relative humidity was found. The incidence of human rhinovirus and enterovirus was independent of temperature. During seasonal IFA outbreaks, the weekly drop of average temperature (compared with the week before) was strongly associated with the IFA incidence recorded the following week. Conclusion A sudden drop in outdoor temperature might activate the annual influenza epidemic in a temperate climate by facilitating aerosol spread in dry air. These conditions also seem to affect the incidence of other respiratory pathogens but not human rhino- or enterovirus, suggesting that routes of infection other than aerosol may be relevant for these agents. © 2016 Elsevier B.V.
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| 15. |
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| 16. |
- Andersson, Ola, 1965-, et al.
(författare)
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Elective caesarean : does delay in cord clamping for 30 s ensure sufficient iron stores at 4 months of age? A historical cohort control study
- 2016
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Ingår i: BMJ Open. - : BMJ. - 2044-6055. ; 6:11
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To compare iron stores in infants born after elective caesarean section (CS) and a 30 s delay of umbilical cord clamping with those born vaginally after early (≤10 s) or delayed (≥180 s) cord clamping.DESIGN: Prospective observational study with historical control.SETTING: Swedish county hospital.POPULATION: 64 infants born after elective CS were compared with a historical control of 166 early clamped and 168 delayed clamped after vaginal birth.METHODS: Blood and iron status were measured in blood samples collected at birth, 48-96 hours after birth, 4 and 12 months of age.PRIMARY AND SECONDARY OUTCOME MEASURES: Ferritin at 4 months of age was the primary outcome, second outcome measures were other indicators of iron status, and haemoglobin, at 4 and 12 months of age, as well as respiratory distress at 1 and 6 hours after birth.RESULTS: At 4 months infants born by elective CS had better iron status than those born vaginally subjected to early cord clamping, shown by higher adjusted mean difference of ferritin concentration (39 µg/L (95% CI 10 to 60)) and mean cell volume (1.8 fL (95% CI 0.6 to 3.0)); and lower levels of transferrin receptors (-0.39 mg/L (95% CI -0.69 to -0.08)). No differences were seen between infants born after elective CS and delayed clamped vaginally born infants at 4 months. No differences were found between groups at 12 months of age.CONCLUSIONS: Waiting to clamp the umbilical cord for 30 s after elective CS results in higher iron stores at 4 months of age compared with early cord clamping after vaginal birth, and seems to ensure iron status comparable with those achieved after 180 s delayed cord clamping after vaginal birth.
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| 17. |
- Andersson, Thord, 1972-, et al.
(författare)
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Geodesic registration for interactive atlas-based segmentation using learned multi-scale anatomical manifolds
- 2018
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Ingår i: Pattern Recognition Letters. - : Elsevier. - 0167-8655 .- 1872-7344. ; 112, s. 340-345
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Tidskriftsartikel (refereegranskat)abstract
- Atlas-based segmentation is often used to segment medical image regions. For intensity-normalized data, the quality of these segmentations is highly dependent on the similarity between the atlas and the target under the used registration method. We propose a geodesic registration method for interactive atlas-based segmentation using empirical multi-scale anatomical manifolds. The method utilizes unlabeled images together with the labeled atlases to learn empirical anatomical manifolds. These manifolds are defined on distinct scales and regions and are used to propagate the labeling information from the atlases to the target along anatomical geodesics. The resulting competing segmentations from the different manifolds are then ranked according to an image-based similarity measure. We used image volumes acquired using magnetic resonance imaging from 36 subjects. The performance of the method was evaluated using a liver segmentation task. The result was then compared to the corresponding performance of direct segmentation using Dice Index statistics. The method shows a significant improvement in liver segmentation performance between the proposed method and direct segmentation. Furthermore, the standard deviation in performance decreased significantly. Using competing complementary manifolds defined over a hierarchy of region of interests gives an additional improvement in segmentation performance compared to the single manifold segmentation.
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| 18. |
- Balliu, Enkeleda, et al.
(författare)
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Selective laser sintering of inkjet-printed silver nanoparticle inks on paper substrates to achieve highly conductive patterns
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Development of cost-effective and environmentally friendly manufacturing methods will enable important advances for the production of large-scale flexible electronics. Laser processing has shown to be a promising candidate that offers a fast and non-destructive way to produce highly conductive patterns on flexible substrates such as plastics. However, an emerging option with a lower environmental impact is instead the use of cellulose-based flexible substrates, such as paper. In this work we investigate the use of laser sintering of silver nanoparticle inks, which were inkjet-printed on three different types of paper. Patterns with a high conductivity could be manufactured where a special care was taken to prevent the substrates from damage by the intense laser light. We found that the best results was obtained for a photopaper, with a conductivity of 1.63 107 S/m corresponding to nearly 26% of the bulk silver conductivity. In addition, we demonstrate laser sintering to fabricate a fully functional near field communication tag printed on a photopaper. Our results can have an important bearing for the development of cost-effective and environmentally friendly production methods for flexible electronics on a large scale.
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| 19. |
- Engholm, Magnus, et al.
(författare)
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A bio-compatible fiber optic pH sensor based on a thin core interferometric technique
- 2019
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Ingår i: Photonics. - : MDPI AG. - 2304-6732. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- There is an increasing demand for compact, reliable and versatile sensor concepts for pH-level monitoring within several industrial, chemical as well as bio-medical applications. Many pH sensors concepts have been proposed, however, there is still a need for improved sensor solutions with respect to reliability, durability and miniaturization but also for multiparameter sensing. Here we present a conceptual verification, which includes theoretical simulations as well as experimental evaluation of a fiber optic pH-sensor based on a bio-compatible pH sensitive material not previously used in this context. The fiber optic sensor is based on a Mach-Zehnder interferometric technique, where the pH sensitive material is coated on a short, typically 20-25 mm thin core fiber spliced between two standard single mode fibers. The working principle of the sensor is simulated by using COMSOL Multiphysics. The simulations are used as a guideline for the construction of the sensors that have been experimentally evaluated in different liquids with pH ranging from 1.95 to 11.89. The results are promising, showing the potential for the development of bio-compatible fiber optic pH sensor with short response time, high sensitivity and broad measurement range. The developed sensor concept can find future use in many medical- or bio-chemical applications as well as in environmental monitoring of large areas. Challenges encountered during the sensor development due to variation in the design parameters are discussed. © 2019 by the authors.
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| 20. |
- Englund, Johanna, 1988, et al.
(författare)
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Deactivation of a Pd/Pt Bimetallic Oxidation Catalyst Used in a Biogas-Powered Euro VI Heavy-Duty Engine Installation
- 2019
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Ingår i: Catalysts. - : MDPI. - 2073-4344. ; 9:12
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Tidskriftsartikel (refereegranskat)abstract
- The reduction of anthropogenic greenhouse gas emissions is crucial to avoid further warming of the planet. We investigated how effluent gases from a biogas powered Euro VI heavy-duty engine impact the performance of a bimetallic (palladium and platinum) oxidation catalyst. Using synthetic gas mixtures, the oxidation of NO, CO, and CH4 before and after exposure to biogas exhaust for 900 h was studied. The catalyst lost most of its activity for methane oxidation, and the activity loss was most severe for the inlet part of the aged catalyst. Here, a clear sintering of Pt and Pd was observed, and higher concentrations of catalyst poisons such as sulfur and phosphorus were detected. The sintering and poisoning resulted in less available active sites and hence lower activity for methane oxidation.
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| 21. |
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| 22. |
- Hammarling, Krister, 1968-, et al.
(författare)
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Broad-range hydrogel-based pH sensor with capacitive readout manufactured on a flexible substrate
- 2018
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Ingår i: Chemosensors. - Basel, Switzerland : MDPI AG. - 2227-9040. ; 6:3
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Tidskriftsartikel (refereegranskat)abstract
- Environmental monitoring of land, water and air, is an area receiving greater attention because of human health and safety concerns. Monitoring the type of pollution and concentration levels is vital, so that appropriate contingency plans can be determined. To effectively monitor the environment, there is a need for new sensors and sensor systems that suits these type of measurements. However, the diversity of sensors suitable for low, battery powered- and large area sensor systems are limited. We have manufactured and characterized a flexible pH sensor using laser processing and blade coating techniques that is able to measure pH between 2.94 and 11.80. The sensor consists of an interdigital capacitance with a pH sensitive hydrogel coating. Thin sensors can reach 95% of their final value value within 3 min, and are stable after 4 min. Good repeatability was achieved in regard to cycling of the sensor with different pH and multiple measurements from dry state. We have also studied the relation between an interdigital capacitance penetration depth and hydrogels expansion. We believe that our passive sensor is suitable to be used in low power and large area sensor networks.
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| 23. |
- Hammarling, Krister, 1968-
(författare)
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Hydrogel-based pH-sensors : Development and characterisation of optical and electrical pH sensors based on stimuli-responsive hydrogels
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The ability to measure the chemical parameter pH is of high importance in many areas. With new government regulations and evolving markets, there is a strong motivation for improving such measurements and conducting research on new types of pH sensors and sensor materials. Stimuli-responsive hydrogels (a group of polymers) have attracted a lot of attention in recent decades, due to their ability to be customized to suit many applications. One specific area where they have attracted attention is pH sensor technology.Two stimuli-responsive hydrogels are used in this thesis. One is a non-toxic hydrogel, 1,4-acryl-terminated oligo(beta-amino esters) (1,4-AOBAE). Although it was previously used in drug- and DNA- delivery systems, it has not (to my knowledge) been used in a sensor configuration, and thus it is interesting to study. The second hydrogel, 1,3-acryl-terminated oligo(beta-amino esters) (1,3-AOBAE), is an improved variant of the first one. This improved hydrogel was synthesized because the original hydrogel crystallizes at room temperature, which meant that it was not optimal for various coating techniques. This hydrogel was characterized and verified for pH responsivity in two sensor configurations: electrical and optical. Designing a hydrogel for a specific application can be a complex procedure due to the many synthesizing parameters. For example, increasing a hydrogel's mechanical strength by introducing a higher degree of cross linking, leads to a smaller mesh size, which in turn leads to a lower diffusion rate and less solution absorption. The two hydrogels examined in this thesis respond to pH changes by absorbing or desorbing water; this change in the hydrogel's water content also changes its effective refractive index and permittivity. These changes can be measured using optical or electrical sensor systems. Three types of sensor systems were used in this thesis to verify the hydrogel's pH response and to ensure that they are suitable for use in thin-film techniques on various substrates (e.g. glass and plastic). The experimental results prove that these hydrogels are suitable for use in both electrical and optical sensor configurations. For electrical systems, a pH range of approximately 3-12 was achieved, and for optical, the range was approximately 2-12. These ranges can likely be improved, as the sensor film delaminated from the substrate at low pHs due to adhesion problems and as measurements above 12 were not conducted.The findings of this thesis could, after more research, have strong implications for the development of improved pH-sensor configurations, especially for medical and healthcare applications and in environmental monitoring.
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| 24. |
- Hammarling, Krister, 1968-, et al.
(författare)
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Synthesis, Curing Behavior and Swell Tests of pH-Responsive Coatings from Acryl-Terminated Oligo(beta-Amino Esters)
- 2018
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Ingår i: CHEMOSENSORS. - : MDPI AG. - 2227-9040. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- The ability of acryl-terminated oligo(beta-amino esters) (AOBAE) to be coated on fibers and printed electronics without solvents and to be cross-linked to a pH-responsive coatings, makes AOBAE-based coatings a potential type of pH-sensor coating. However, there are currently no reports of AOBAEs used as a pH-responsive coating material in sensor applications. Here we present an investigation of the synthesis, curing behavior and swell tests of AOBAEs. AOBAEs were synthesized from reacting an excess of asymmetric diacrylates with piperazine without the use of any solvents. They were then cross-linked to an insoluble network by UV-curing. Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the AOBAEs. NMR was used to clarify the irregular structure of the AOBAE. FTIR was used to monitor the effects of UV-curing dose and air exposure on monomer conversion during curing. An interferometric technique was used to monitor the swelling behavior of the coating in response to pH variations. Swell experiments showed that the AOBAE also responded to pH variations after polymerization. Therefore, AOBAE is an interesting class of material with potential use as a pH responsive coating in optical-and printed electronics pH-sensors applications.
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| 25. |
- Jansson, Marcus, et al.
(författare)
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Water Hammer Induced Cavitation - A Numerical and Experimental Study
- 2017
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Ingår i: Fluid Power in the Digital Age.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Cavitation erosion is one of the main concerns in hydraulic rock drills and can reduce both performance as well as life span. Current simulation tools can detect a potential risk of cavitation, however, the equations do not include cavitation physics and therefore cannot estimate the severity nor erosion locations. In order to evaluate the cavitation damage, long term tests are performed which are both costly and time consuming. With better computational capacity and more accurate numerical flow models, the possibilities to simulate the course of cavitation have increased. So far, most numerical studies on cavitation focus on steady-state problems while studies on hydraulic transients and water hammer effects have received less attention. This paper is a step towards simulation of water hammer induced cavitation and cavitation erosion in pipe flow using Computational Fluid Dynamics (CFD). In order to validate the results, experimental measurements are performed with a test equipment that creates hydraulic transients in a pipe and records these using piezoelectric pressure sensors. The results from CFD are compared to both the experimental data and to numerical results from a software called Hopsan, a one-dimensional multi-domain system simulation tool that uses wave characteristics to calculate pressures and flows. For smaller transients where no cavitation occur, all results show good agreement. For larger transients with cavitation, the results from Hopsan do not longer agree with the measurements, while the CFD model still performs well and is able to predict both formation and collapse of cavitation.
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| 26. |
- Kamp, Carl Justin, 1982, et al.
(författare)
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Nanofabricated catalyst particles for the investigation of catalytic carbon oxidation by oxygen spillover
- 2017
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 33:20, s. 4903-4912
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Tidskriftsartikel (refereegranskat)abstract
- The catalytic oxidation of carbon by molecular oxygen was studied using C/Pt, Pt/C, Pt/Al2O3/C, Pt/CeO2/C, Al2O3/C and CeO2/C model samples prepared by hole-mask colloidal lithography. By this technique the degree of contact between platinum and carbon was controlled with high precision. The oxidation of carbon was monitored using atomic force microscopy and scanning electron microscopy. The results show that Pt in direct contact with carbon catalyzes the oxidation of carbon by spillover of dissociated oxygen from Pt to carbon. By physically separating Pt and carbon with a 10 nm thin spacer layer of Al2O3, the oxygen spillover was entirely blocked. However, through a corresponding spacer layer of CeO2, carbon oxidation was still observed, either by oxygen spillover from Pt to carbon or directly dissociated on the ceria, although at a slower rate compared to the case with no spacer layer between Pt and carbon.
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| 27. |
- Lam, Monika M., 1987-
(författare)
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Characterization of PAC-contaminated soil with the focus on availability, leachability and biological activities
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Current risk assessments of polycyclic aromatic compounds (PACs)-contaminated soil are often based on the 16 priority PAHs and do not consider availability of PACs in soil sufficiently. This may lead to uncertainties of the assessment, since important contaminants can be overlooked and only a small fraction of contaminants is available for the uptake for organisms. The overall aim of this thesis was to develop a refined and enhanced analytical approach based on both chemical and bioassay analysis coupled to passive sampling with polyoxymethylene (POM) and leaching tests that can provide a more comprehensive picture of chemical pollution at PAC-contaminated sites. To achieve this, bioassay-specific relative potency factors (REPs) of PACs were determined for the H4IIE-luc bioassay, detecting AhR-mediated activity, and for the VM7luc4E2 transactivation assay, detecting ER-mediated activity for the use in potency-balance analysis. Results of uptake-experiments of PACs in earthworms and POM suggested that POM is a suitable tool to study availability of AhR and ER agonists in soil. Availability and mobility of PACs in soil were investigated by the use of POM and leaching tests. The results of potency-balance analysis showed that in soil samples, in POM-fractions or in leachates, a large fraction of AhR- or ER-agonists remained unexplained, despite the use of a large number of REPs. In addition, coupling of chemical and biological analysis to passive sampling or leaching tests revealed that only a small fraction of the total mass of PACs in the soil is available or leachable in soil. The results suggests that the use of only the total concentration in soil while ignoring unknown toxicants will lead to great uncertainties in the risk assessment. Therefore, effect-based screening using bioassays, taking availability and mobility of compounds into account, as well as a widened chemical analysis should be included in modern hazard- and risk assessment of PAH contaminated soils.
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| 28. |
- Magnusson, Jesper, et al.
(författare)
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Incidence of Hepatitis E Antibodies in Swedish Lung Transplant Recipients
- 2015
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Ingår i: Transplantation Proceedings. - : Elsevier BV. - 0041-1345. ; 47:6, s. 1972-1976
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Tidskriftsartikel (refereegranskat)abstract
- Background. Hepatitis E virus (REV) is an important cause of acute and chronic hepatitis in solid organ transplant recipients, especially liver transplant recipients. However, less is known of the incidence and prevalence of HEV in lung transplant recipients. Methods. In a prospective study, 62 patients were observed during the first year after lung transplantation. Sera were analyzed for anti-REV immunoglobulin G (IgG) and IgM at 12 months after transplantation. Samples positive for anti-REV were also analyzed for REV RNA by polymerase chain reaction. Pretransplantation samples were analyzed for patients with detectable anti-REV 1 year after transplantation. Results. Eight patients (13%) had anti-REV IgG at the 12-month follow-up sample. HEV RNA could not be detected in any of these samples. One of these patients seroconverted during the follow-up without developing acute or chronic hepatitis. Conclusions. Our results show that the prevalence of REV antibodies among Swedish lung transplant recipients is similar when compared to the general population. It also suggests that the risk for REV antibody seroconversion during first year is limited.
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| 29. |
- Marcusson, Jan, et al.
(författare)
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Proactive healthcare for frail elderly persons : study protocol for a prospective controlled primary care intervention in Sweden
- 2019
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 9:5
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Tidskriftsartikel (refereegranskat)abstract
- Introduction The provision of healthcare services is not dedicated to promoting maintenance of function and does not target frail older persons at high risk of the main causes of morbidity and mortality. The aim of this study is to evaluate the effects of a proactive medical and social intervention in comparison with conventional care on a group of persons aged 75 and older selected by statistical prediction.Methods and analysis In a pragmatic multicentre primary care setting (n=1600), a prediction model to find elderly (75+) persons at high risk of complex medical care or hospitalisation is used, followed by proactive medical and social care, in comparison with usual care. The study started in April 2017 with a run-in period until December 2017, followed by a 2-year continued intervention phase that will continue until the end of December 2019. The intervention includes several tools (multiprofessional team for rehabilitation, social support, medical care home visits and telephone support). Primary outcome measures are healthcare cost, number of hospital care episodes, hospital care days and mortality. Secondary outcome measures are number of outpatient visits, cost of social care and informal care, number of prescribed drugs, health-related quality of life, cost-effectiveness, sense of security, functional status and ability. We also study the care of elderly persons in a broader sense, by covering the perspectives of the patients, the professional staff and the management, and on a political level, by using semistructured interviews, qualitative methods and a questionnaire.Ethics and dissemination Approved by the regional ethical review board in Linköping (Dnr 2016/347-31). The results will be presented in scientific journals and scientific meetings during 2019–2022 and are planned to be used for the development of future care models.
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| 30. |
- Sansone, Martina, et al.
(författare)
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Molecular characterization of a nosocomial outbreak of influenza B virus in an acute care hospital setting
- 2019
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Ingår i: Journal of Hospital Infection. - : Elsevier BV. - 0195-6701. ; 101:1, s. 30-37
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To describe a hospital outbreak of influenza B virus (InfB) infection during season 2015/2016 by combining clinical and epidemiological data with molecular methods. Methods: Twenty patients diagnosed with InfB from a hospital outbreak over a four-week-period were included. Nasopharyngeal samples (NPS) positive for InfB by multiplex real-time polymerase chain reaction were sent for lineage typing and whole genome sequencing (WGS). Medical records were reviewed retrospectively for data regarding patient characteristics, localization, exposure and outcome, and assembled into a timeline. In order to find possible connections to the hospital outbreak, all patients with a positive NPS for influenza from the region over an extended time period were also reviewed. Findings: All 20 cases of InfB were of subtype B/Yamagata, and 17 of 20 patients could be linked to each other by either shared room or shared ward. WGS was successful or partially successful for 15 of the 17 viral isolates, and corroborated the epidemiological link supporting a close relationship. In the main affected ward, 19 of 75 inpatients were infected with InfB during the outbreak period, resulting in an attack rate of 25%. One probable case of influenza-related death was identified. Conclusion: InfB may spread within an acute care hospital, and advanced molecular methods may facilitate assessment of the source and extent of the outbreak. A multifaceted approach, including rapid diagnosis, early recognition of outbreak situations, simple rules for patient management and the use of regular infection control measures, may prevent nosocomial transmission of influenza virus. (C) 2018 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
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| 31. |
- Sjöblom, Jonas, 1968, et al.
(författare)
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Catalytic aftertreatment of particulate matter
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Particulate emissions cause millions of premature deaths every year and emissions from roadtransportation makes a significant contribution. The last years more stringent emissionsregulations will enforce the implementation of particulate filters and much of the health issuescan be significantly reduced. Since the efficiency of the filter depends on a range ofparameters and since it also brings an increased fuel penalty from the increased pressure drop,it is very important to understand the different mechanisms in the filter. Through thisunderstanding, it becomes possible to eliminate the negative heath issues from particulateemissions with a minimal fuel penalty and thereby also lowering CO2 emissions.The particulate emissions, which mainly consists of soot (graphitized carbon), is oxidized inthe filter often using catalysis. This project has been focusing on experiments both in lab scaleand connected to full scale (engine bench testing). The project has also developed amethodology to enable further research within the area. The project has demonstrated that theoxidation mechanisms depends of more factors than what is usually considered in theautomotive industry. These factors include the previous history of the soot, interaction effectsof gas phase components and the sot surface as well as mass transfer limitations.In order to improve the performance of particulate reduction from road vehicles, improvedmathematical models are needed. This becomes possible by including the phenomenademonstrated in this project. More work is needed until validated models executable in realtimeis ready, but by bridging knowledge between lab scale and full scale, this work will bemore efficient.
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| 32. |
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| 33. |
- Zakrisson, Johan, 1986-, et al.
(författare)
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Cell shape identification using digital holographic microscopy
- 2015
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Ingår i: Applied Optics. - : Optical Society of America. - 1559-128X .- 2155-3165. ; 54:24, s. 7442-7448
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Tidskriftsartikel (refereegranskat)abstract
- We present a cost-effective, simple and fast digital holographic microscopy method based upon Rayleigh-Sommerfeld back propagation for identification of the geometrical shape of a cell. The method was tested using synthetic hologram images generated by ray-tracing software and from experimental images of semi-transparent spherical beads and living red blood cells. Our results show that by only using the real part of the back-reconstructed amplitude the proposed method can provide information of the geometrical shape of the object and at the same time accurately determine the axial position of the object under study. The proposed method can be used in flow chamber assays for pathophysiological studies where fast morphological changes of cells are studied in high numbers and at different heights.
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| 34. |
- Zamora, Juan Carlos, et al.
(författare)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Tidskriftsartikel (refereegranskat)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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