Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
DisciplineDiscipline
-
Is Peer ReviewedIs Peer Reviewed
-
Item TypeItem Type
-
SubjectSubject
-
YearFrom:-To:
-
More FiltersMore FiltersSourceLanguage
Done
Filters
Reset
48
result(s) for
"Bulla, Peter"
Sort by:
Can follow up lung ultrasound in Coronavirus Disease-19 patients indicate clinical outcome?
by
Fusco, Stefano
,
Göpel, Siri
,
Klein, Constantin
in
Biology and Life Sciences
,
Clinical outcomes
,
Coronaviruses
2021
To evaluate whether there is a change in findings of coronavirus disease 2019 patients in follow up lung ultrasound and to determine whether these findings can predict the development of severe disease. In this prospective monocentric study COVID-19 patients had standardized lung ultrasound (12 area evaluation) at day 1, 3 and 5. The primary end point was detection of pathologies and their change over time. The secondary end point was relationship between change in sonographic results and clinical outcome. Clinical outcome was assessed on development of severe disease defined as need for intensive care unit. Data of 30 patients were analyzed, 26 patients with follow-up lung ultrasound. All of them showed lung pathologies with dynamic patterns. 26,7% developed severe disease tending to have an ubiquitous lung involvement in lung ultrasound. In patients with need for intensive care unit a previously developed increase in B-lines, subpleural consolidations and pleural line irregularities was more common. A statistically significant association between change in B-lines as well as change in pleural line irregularities and development of severe disease was observed (p<0,01). The present study demonstrates that follow up lung ultrasound can be a powerful tool to track the evolution of disease and suggests that lung ultrasound is able to indicate an impending development of severe disease in COVID-19 patients.
Journal Article
An updated nuclear-physics and multi-messenger astrophysics framework for binary neutron star mergers
by
Tews, Ingo
,
Pang, Peter T. H.
,
Mansingh, Gargi
in
639/33/34/4118
,
639/33/34/4127
,
639/33/34/864
2023
The multi-messenger detection of the gravitational-wave signal GW170817, the corresponding kilonova AT2017gfo and the short gamma-ray burst GRB170817A, as well as the observed afterglow has delivered a scientific breakthrough. For an accurate interpretation of all these different messengers, one requires robust theoretical models that describe the emitted gravitational-wave, the electromagnetic emission, and dense matter reliably. In addition, one needs efficient and accurate computational tools to ensure a correct cross-correlation between the models and the observational data. For this purpose, we have developed the Nuclear-physics and Multi-Messenger Astrophysics framework NMMA. The code allows incorporation of nuclear-physics constraints at low densities as well as X-ray and radio observations of isolated neutron stars. In previous works, the NMMA code has allowed us to constrain the equation of state of supranuclear dense matter, to measure the Hubble constant, and to compare dense-matter physics probed in neutron-star mergers and in heavy-ion collisions, and to classify electromagnetic observations and perform model selection. Here, we show an extension of the NMMA code as a first attempt of analyzing the gravitational-wave signal, the kilonova, and the gamma-ray burst afterglow simultaneously. Incorporating all available information, we estimate the radius of a 1.4
M
⊙
neutron star to be
R
=
11.9
8
−
0.40
+
0.35
km.
The Nuclear-physics and Multi-Messenger Astrophysics framework, NMMA, combines multiple information from neutron stars and neutron star mergers. Here, the authors show an update of the NMMA framework to constrain neutron star equation of state by simultaneously analyzing multi-messenger observations.
Journal Article
Constraining neutron-star matter with microscopic and macroscopic collisions
by
Tews, Ingo
,
Agarwal, Kshitij
,
Pang, Peter T. H.
in
639/33/34/4118
,
639/33/34/864
,
639/766/387/1126
2022
Interpreting high-energy, astrophysical phenomena, such as supernova explosions or neutron-star collisions, requires a robust understanding of matter at supranuclear densities. However, our knowledge about dense matter explored in the cores of neutron stars remains limited. Fortunately, dense matter is not probed only in astrophysical observations, but also in terrestrial heavy-ion collision experiments. Here we use Bayesian inference to combine data from astrophysical multi-messenger observations of neutron stars
1
–
9
and from heavy-ion collisions of gold nuclei at relativistic energies
10
,
11
with microscopic nuclear theory calculations
12
–
17
to improve our understanding of dense matter. We find that the inclusion of heavy-ion collision data indicates an increase in the pressure in dense matter relative to previous analyses, shifting neutron-star radii towards larger values, consistent with recent observations by the Neutron Star Interior Composition Explorer mission
5
–
8
,
18
. Our findings show that constraints from heavy-ion collision experiments show a remarkable consistency with multi-messenger observations and provide complementary information on nuclear matter at intermediate densities. This work combines nuclear theory, nuclear experiment and astrophysical observations, and shows how joint analyses can shed light on the properties of neutron-rich supranuclear matter over the density range probed in neutron stars.
The physics of dense matter extracted from neutron star collision data is demonstrated to be consistent with information obtained from heavy-ion collisions, and analyses incorporating both data sources as well as information from nuclear theory provide new constraints for neutron star matter.
Journal Article
Discovery and Confirmation of the Shortest Gamma-Ray Burst from a Collapsar
by
Coughlin, Michael W
,
Bulla, Mattia
,
Bellm, Eric
in
639/33/34/4121
,
639/33/34/4127
,
639/33/34/864
2021
Gamma-ray bursts (GRBs) are among the brightest and most energetic events in the Universe. The duration and hardness distribution of GRBs has two clusters, now understood to reflect (at least) two different progenitors. Short-hard GRBs (SGRBs; T(sub 90) < 2 s) arise from compact binary mergers, and long-soft GRBs (LGRBs; T(sub 90) > 2 s) have been attributed to the collapse of peculiar massive stars (collapsars). The discovery of SN 1998bw/GRB 980425 marked the first association of an LGRB with a collapsar, and AT 2017gfo/GRB 170817A/GW170817 marked the first association of an SGRB with a binary neutron star merger, which also produced a gravitational wave. Here, we present the discovery of ZTF20abwysqy (AT2020scz), a fast-fading optical transient in the Fermi satellite and the Interplanetary Network localization regions of GRB 200826A; X-ray and radio emission further confirm that this is the afterglow. Follow-up imaging (at rest-frame 16.5 days) reveals excess emission above the afterglow that cannot be explained as an underlying kilonova, but which is consistent with being the supernova. Although the GRB duration is short (rest-frame T90 of 0.65 s), our panchromatic follow-up data confirm a collapsar origin. GRB 200826A is the shortest LGRB found with an associated collapsar; it appears to sit on the brink between a successful and a failed collapsar. Our discovery is consistent with the hypothesis that most collapsars fail to produce ultra-relativistic jets.
Journal Article
Distinct Roles of Classical and Lectin Pathways of Complement in Preeclamptic Placentae
by
Gulino, Alessandro
,
Belmonte, Beatrice
,
Ricci, Giuseppe
in
Animal models
,
Antigens
,
Biomarkers
2022
Pre-eclampsia is a pregnancy complication characterized by defective vascular remodeling in maternal decidua responsible for reduced blood flow leading to functional and structural alterations in the placenta. We have investigated the contribution of the complement system to decidual vascular changes and showed that trophoblasts surrounding unremodeled vessels prevalent in preeclamptic decidua fail to express C1q that are clearly detected in cells around remodeled vessels predominant in control placenta. The critical role of C1q is supported by the finding that decidual trophoblasts of female C1qa -/- pregnant mice mated to C1qa +/+ male mice surrounding remodeled vessels express C1q of paternal origin. Unlike C1qa -/- pregnant mice, heterozygous C1qa +/- and wild type pregnant mice share a high percentage of remodeled vessels. C1q was also found in decidual vessels and stroma of normal placentae and the staining was stronger in preeclamptic placentae. Failure to detect placental deposition of C1r and C1s associated with C1q rules out complement activation through the classical pathway. Conversely, the intense staining of decidual endothelial cells and villous trophoblast for ficolin-3, MASP-1 and MASP-2 supports the activation of the lectin pathway that proceeds with the cleavage of C4 and C3 and the assembly of the terminal complex. These data extend to humans our previous findings of complement activation through the lectin pathway in an animal model of pre-eclampsia and provide evidence for an important contribution of C1q in decidual vascular remodeling.
Journal Article
The Influence of Board Characteristics on Dividend Policy
by
Bulla, Denis
,
Alala, Ondiek Benedict
,
Vuhyah, Peter Anjeyo
in
Business metrics
,
Capital markets
,
Capital stock
2024
Dividend payout is one of financial options that Saccos consider as part of the key performance indicators for Saccos. Deposit taking Saccos in Kenya have faced numerous challenges namely, governance, managerial and operational such that the performance of a number of them continues to be sub optimal according to the report by SASRA. Therefore, this study sought to examine the influence of board characteristics on dividend policy of deposit taking Saccos in Kenya under guidance by agency cost theory. The study utelized causal design and descriptive survey design. The targeted population was 403 stakeholders sampling 201 through stratified simple random sampling. The sacco directors/chairpersons and the CFO/CEOs formed unit of analysis. Closed ended questionnaires were applied for primary data. A list of 20 Saccos in Starehe Sub County, Nairobi County were basis for pilot test to establish reliability and validity of research instruments. Cronbach Alpha was employed to ascertain reliability, whereas content and construct validity were utilized to attain validity. The data underwent analysis through the application of descriptive as well as inferential statistics. The investigation ensured that the assumptions of linear regression were satisfied before conducting numerous linear regressions. Tables were used to present data. The results indicated a positive significant association between board characteristics practices and dividend policy P:0.000<0.05 hence conclusive that deposit-taking Saccos in Kenya focused on board characteristics as envisaged. The study recommended that Sacco’s should diverse the board features to ensure they accommodate the dividend policy framework.
Journal Article
A pragmatic health centre-based evaluation comparing the effectiveness of a PCV13 schedule change from 3+0 to 2+1 in a high pneumococcal carriage and disease burden setting in Malawi: a study protocol
by
Chirombo, James
,
Kachala, Jean
,
Brown, Comfort
in
Carrier State - epidemiology
,
Child
,
Child, Preschool
2021
IntroductionStreptococcus pneumoniae (the pneumococcus) is commonly carried as a commensal bacterium in the nasopharynx but can cause life-threatening disease. Transmission occurs by human respiratory droplets and interruption of this process provides herd immunity. A 2017 WHO Consultation on Optimisation of pneumococcal conjugate vaccines (PCV) Impact highlighted a substantial research gap in investigating why the impact of PCV vaccines in low-income countries has been lower than expected. Malawi introduced the 13-valent PCV (PCV13) into the national Expanded Programme of Immunisations in 2011, using a 3+0 (3 primary +0 booster doses) schedule. With evidence of greater impact of a 2+1 (2 primary +1 booster dose) schedule in other settings, including South Africa, Malawi’s National Immunisations Technical Advisory Group is seeking evidence of adequate superiority of a 2+1 schedule to inform vaccine policy.MethodsA pragmatic health centre-based evaluation comparing impact of a PCV13 schedule change from 3+0 to 2+1 in Blantyre district, Malawi. Twenty government health centres will be randomly selected, with ten implementing a 2+1 and 10 to continue with the 3+0 schedule. Health centres implementing 3+0 will serve as the direct comparator in evaluating 2+1 providing superior direct and indirect protection against pneumococcal carriage. Pneumococcal carriage surveys will evaluate carriage prevalence among children 15–24 months, randomised at household level, and schoolgoers 5–10 years of age, randomly selected from school registers. Carriage surveys will be conducted 18 and 33 months following 2+1 implementation.AnalysisThe primary endpoint is powered to detect an effect size of 50% reduction in vaccine serotype (VT) carriage among vaccinated children 15–24 months old, expecting a 14% and 7% VT carriage prevalence in the 3+0 and 2+1 arms, respectively.Ethics and disseminationThe study has been approved by the Malawi College of Medicine Research Ethics Committee (COMREC; Ref: P05.19.2680), the University College London Research Ethics Committee (Ref: 8603.002) and the University of Liverpool Research Ethics Committee (Ref: 5439). The results from this study will be actively disseminated through manuscript publications and conference presentations.Trial registration numberNCT04078997.
Journal Article
S. aureus alpha-toxin monomer binding and heptamer formation in host cell membranes – Do they determine sensitivity of airway epithelial cells toward the toxin?
by
Hildebrandt, Jan-Peter
,
Möller, Nils
,
Hildebrandt, Petra
in
Abundance
,
Bacterial toxins
,
Binding
2020
Alpha-toxin (Hla) is a major virulence factor of Staphylococcus aureus (S. aureus) and plays an important role in S. aureus-induced pneumonia. It binds as a monomer to the cell surface of eukaryotic host cells and forms heptameric transmembrane pores. Sensitivities toward the toxin of various types of potential host cells have been shown to vary substantially, and the reasons for these differences are unclear. We used three human model airway epithelial cell lines (16HBE14o-, S9, A549) to correlate cell sensitivity (measured as rate of paracellular gap formation in the cell layers) with Hla monomer binding, presence of the potential Hla receptors ADAM10 or α5β1 integrin, presence of the toxin-stabilizing factor caveolin-1 as well as plasma membrane lipid composition (phosphatidylserine/choline, sphingomyelin). The abundance of ADAM10 correlated best with gap formation or cell sensitivities, respectively, when the three cell types were compared. Caveolin-1 or α5β1 integrin did not correlate with toxin sensitivity. The relative abundance of sphingomyelin in plasma membranes may also be used as a proxi for cellular sensitivity against alpha-toxin as sphingomyelin abundances correlated well with the intensities of alpha-toxin mediated gap formation in the cell layers.
Journal Article
Urban birds' tolerance towards humans was largely unaffected by COVID-19 shutdown-induced variation in human presence
by
Kaisanlahti-Jokimäki, Marja-Liisa
,
Szakony, Sára
,
Weston, Michael A.
in
631/158/856
,
631/158/858
,
Animals
2024
The coronavirus disease 2019 (COVID-19) pandemic and respective shutdowns dramatically altered human activities, potentially changing human pressures on urban-dwelling animals. Here, we use such COVID-19-induced variation in human presence to evaluate, across multiple temporal scales, how urban birds from five countries changed their tolerance towards humans, measured as escape distance. We collected 6369 escape responses for 147 species and found that human numbers in parks at a given hour, day, week or year (before and during shutdowns) had a little effect on birds’ escape distances. All effects centered around zero, except for the actual human numbers during escape trial (hourly scale) that correlated negatively, albeit weakly, with escape distance. The results were similar across countries and most species. Our results highlight the resilience of birds to changes in human numbers on multiple temporal scales, the complexities of linking animal fear responses to human behavior, and the challenge of quantifying both simultaneously in situ.
A study on urban birds' tolerance towards humans highlights their resilience to changes in human numbers, induced by COVID-19 shutdowns, across multiple temporal scales.
Journal Article
Retracted Article: Constraining Neutron-Star Matter — Combination of heavy-ion experiments, astronomy and theory
2023
This paper has been formally retracted because it has been accidentally published twice in the same volume. Request approved by the proceedings Editor and the Publisher on January 29, 2024.
Journal Article