543 research outputs found
On admissibility criteria for weak solutions of the Euler equations
We consider solutions to the Cauchy problem for the incompressible Euler
equations satisfying several additional requirements, like the global and local
energy inequalities. Using some techniques introduced in an earlier paper we
show that, for some bounded compactly supported initial data, none of these
admissibility criteria singles out a unique weak solution.
As a byproduct we show bounded initial data for which admissible solutions to
the p-system of isentropic gas dynamics in Eulerian coordinates are not unique
in more than one space dimension.Comment: 33 pages, 1 figure; v2: 35 pages, corrected typos, clarified proof
Birdsfoot trefoil seed production in northern Minnesota
1 online resource (PDF, 4 pages)This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu.Elling, Laddie J.; McGraw, Robert L.; Wyse, Donald L.. (1985). Birdsfoot trefoil seed production in northern Minnesota. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/207449
Toward Automated Enzymatic Glycan Synthesis in a Compartmented Flow Microreactor System
Immobilized microfluidic enzyme reactors (IMER) are of particular interest for automation of enzyme cascade reactions. Within an IMER, substrates are converted by paralleled immobilized enzyme modules and intermediate products are transported for further conversion by subsequent enzyme modules. By optimizing substrate conversion in the spatially separated enzyme modules purification of intermediate products is not necessary, thus shortening process time and increasing space‐time yields. The IMER enables the development of efficient enzyme cascades by combining compatible enzymatic reactions in different arrangements under optimal conditions and the possibility of a cost‐benefit analysis prior to scale‐up. These features are of special interest for automation of enzymatic glycan synthesis. We here demonstrate a compartmented flow microreactor system using six magnetic enzyme beads (MEBs) for the synthesis of the non‐sulfated human natural killer cell‐1 (HNK‐1) glycan epitope. MEBs are assembled to build compartmented enzyme modules, consisting of enzyme cascades for the synthesis of uridine 5′‐ diphospho‐α‐ d‐galactose (UDP‐Gal) and uridine 5′‐diphospho‐α‐d‐glucuronic acid (UDP‐GlcA), the donor substrates for the Leloir glycosyltransferases β4‐galactosyltransferase and β3‐glucuronosyltransferase, respectively. Glycan synthesis was realized in an automated microreactor system by a cascade of individual enzyme module compartments each performing under optimal conditions. The products were analyzed inline by an MS‐system connected to the microreactor. The high synthesis yield of 96% for the non‐sulfated HNK‐1 glycan epitope indicates the excellent performance of the automated enzyme module cascade. Furthermore, combinations of other MEBs for nucleotide sugars synthesis with MEBs of glycosyltransferases have the potential for a fully automated and programmed glycan synthesis in a compartmented flow microreactor system
Of autoregressive continuous time model parameters estimation
This article revisits a sequential approach to the estimation of the parameter in a first-order autoregressive model (AR(1)) with continuous time. There is provided a numerical study to get a results of sequential estimations of the parameter in first-order autoregressive model with continuous time and is computed a stopping rule and the optimal time of observations. Also there is provided a comparing analysis of estimation results with using the sequential approach both the optimal time of observations
Deceased donor organ procurement injuries in the United States
AIM: To determine the incidence of surgical injury during deceased donor organ procurements.
METHODS: Organ damage was classified into three tiers, from 1-3, with the latter rendering the organ non-transplantable. For 12 consecutive months starting in January of 2014, 36 of 58 organ procurement organization's (OPO)'s prospectively submitted quality data regarding organ damage (as reported by the transplanting surgeon and confirmed by the OPO medical director) seen on the procured organ.
RESULTS: These 36 OPOs recovered 5401 of the nations's 8504 deceased donors for calendar year 2014. A total of 19043 organs procured were prospectively analyzed. Of this total, 59 organs sustained damage making them non-transplantable (0 intestines; 4 pancreata; 5 lungs; 6 livers; 43 kidneys). The class 3 damage was spread over 22 (of 36) reporting OPO's.
CONCLUSION: While damage to the procured organ is rare with organ loss being approximately 0.3% of procured organs, loss of potential transplantable organs does occur during procurement
Multi-omic studies on missense PLG variants in families with otitis media
Otitis media (OM), a very common disease in young children, can result in hearing loss. In order to potentially replicate previously reported associations between OM and PLG, exome and Sanger sequencing, RNA-sequencing of saliva and middle ear samples, 16S rRNA sequencing, molecular modeling, and statistical analyses including transmission disequilibrium tests (TDT) were performed in a multi-ethnic cohort of 718 families and simplex cases with OM. We identified four rare PLG variants c.112A > G (p.Lys38Glu), c.782G > A (p.Arg261His), c.1481C > T (p.Ala494Val) and c.2045 T > A (p.Ile682Asn), and one common variant c.1414G > A (p.Asp472Asn). However TDT analyses for these PLG variants did not demonstrate association with OM in 314 families. Additionally PLG expression is very low or absent in normal or diseased middle ear in mouse and human, and salivary expression and microbial a-diversity were non-significant in c.1414G > A (p.Asp472Asn) carriers. Based on molecular modeling, the novel rare variants particularly c.782G > A (p.Arg261His) and c.2045 T > A (p.Ile682Asn) were predicted to affect protein structure. Exploration of other potential disease mechanisms will help elucidate how PLG contributes to OM susceptibility in humans. Our results underline the importance of following up findings from genome-wide association through replication studies, preferably using multi-omic datasets.Peer reviewe
The changing spectrum of microbial aetiology of respiratory tract infections in hospitalized patients before and during the COVID-19 pandemic
Background: The COVID-19 pandemic was met with strict containment measures. We hypothesized that societal infection control measures would impact the number of hospital admissions for respiratory tract infections, as well as, the spectrum of pathogens detected in patients with suspected community acquired pneumonia (CAP).
Methods: This study is based on aggregated surveillance data from electronic health records of patients admitted to the hospitals in Bergen Hospital Trust from January 2017 through June 2021, as well as, two prospective studies of patients with suspected CAP conducted prior to and during the COVID-19 pandemic (pre-COVID cohort versus COVID cohort, respectively). In the prospective cohorts, microbiological detections were ascertained by comprehensive PCR-testing in lower respiratory tract specimens. Mann–Whitney’s U test was used to analyse continuous variables. Fisher’s exact test was used for analysing categorical data. The number of admissions before and during the outbreak of SARS-CoV-2 was compared using two-sample t-tests on logarithmic transformed values.
Results: Admissions for respiratory tract infections declined after the outbreak of SARS-CoV-2 (p < 0.001). The pre-COVID and the COVID cohorts comprised 96 and 80 patients, respectively. The proportion of viruses detected in the COVID cohort was significantly lower compared with the pre-COVID cohort [21% vs 36%, difference of 14%, 95% CI 4% to 26%; p = 0.012], and the proportion of bacterial- and viral co-detections was less than half in the COVID cohort compared with the pre-COVID cohort (19% vs 45%, difference of 26%, 95% CI 13% to 41%; p < 0.001). The proportion of bacteria detected was similar (p = 0.162), however, a difference in the bacterial spectrum was observed in the two cohorts. Haemophilus influenzae was the most frequent bacterial detection in both cohorts, followed by Streptococcus pneumoniae in the pre-COVID and Staphylococcus aureus in the COVID cohort.
Conclusion: During the first year of the COVID-19 pandemic, the number of admissions with pneumonia and the microbiological detections in patients with suspected CAP, differed from the preceding year. This suggests that infection control measures related to COVID-19 restrictions have an overall and specific impact on respiratory tract infections, beyond reducing the spread of SARS-CoV-2.publishedVersio
Structural barriers to knowledge transfer and exchange among men and women in low-, middle- and high-income countries: an international cross-sectional study with vaccine researchers in 44 countries
Background:
Globally, women constitute 30% of researchers. Despite an increasing proportion of women in research, they are still less likely to have international collaborations. Literature on barriers to knowledge transfer and exchange (KTE) between men and women remains limited. This study aimed to assess perceived gender barriers to KTE activities in vaccination-related research in low-, middle- and high-income countries.
Methods:
This was a cross-sectional data assessment from a self-administered questionnaire distributed to researchers in the field of vaccination research. The administered questionnaire was developed and validated by WHO and McMaster University. Descriptive statistics were carried out. Structural factors of KTE were assessed using 12 statements measured with a five-point Likert scale, ranging from 1 (strongly disagree) to 5 (strongly agree). An index ranging from 12 to 60 points was created to assess structural factors of KTE, with higher score indicating fewer perceived barriers. Multivariable linear regression modelling was applied to examine the association between KTE barriers and gender.
Results:
A total of 158 researchers were included in the analysis. Regardless of gender and country of affiliation, researchers experienced challenges with respect to KTE activities; particularly factors related to the availability of human and financial resources and level of technical expertise among their target audience. We were also able to identify perceived facilitators among men and women, such as the presence of structures that link researchers and target audiences, the investment of target audiences in KTE efforts and the presence of stable contacts among target audiences. Our linear regression analysis showed that women perceived more barriers than men (R2 = 0.014; B = −1.069; 95% CI −4.035; 1.897).
Conclusions:
Men and women shared common perspectives on barriers to KTE. KTE activities could be strengthened by improving structural efforts to reduce gender differences and increase collaborations between researchers and their target audience
- …