3,813 research outputs found
Automated measurement of coagulation and fibrinolytic activation markers: Outcomes in coronavirus disease 2019 (COVID-19) patients
BACKGROUND: Severe coronavirus disease 2019 (COVIDâ19) is characterized by marked hypoxaemia and lung oedema, often accompanied by disordered blood coagulation and fibrinolytic systems, endothelial damage and intravascular fibrin deposition. PATIENTS/METHODS: We present a retrospective observational study of 104 patients admitted to hospital with COVIDâ19. Plasma samples were collected within 72âh of admission. In addition to routine coagulation and haematology testing, soluble thrombomodulin (sTM), thrombinâantithrombin (TAT), tissue plasminogen activatorâplasminogen activator inhibitor 1 complex (tPAIâC) and plasminâα2 antiplasmin complex (PIC) were performed by automated chemiluminescent enzyme immunoassays. RESULTS: Significantly higher levels of Dâdimer, TAT, sTM and tPAIâC were observed in nonâsurvivors compared to survivors. To confirm which parameters were independent risk factors for mortality, multiple logistic regression was performed on Dâdimer, TAT. sTM, tPAIâC and PIC data. Only increasing sTM was significantly associated with mortality, with an odds ratio of 1.065 for each 1.0 TU/mL increment (95% CI 1.025â1.115). CONCLUSIONS: Of the haemostatic variables measured, sTM, which can be rapidly assayed, is the best independent predictor of mortality in patients hospitalized with COVIDâ19, and this suggests that endothelial dysfunction plays an important role in disease progression
Investigations of excitation energy transfer and intramolecular interactions in a nitrogen corded distrylbenzene dendrimer system.
The photophysics of an amino-styrylbenzene dendrimer (A-DSB) system is probed by time-resolved and steady state luminescence spectroscopy. For two different generations of this dendrimer, steady state absorption, emission, and photoluminescence excitation spectra are reported and show that the efficiency of energy transfer from the dendrons to the core is very close to 100%. Ultrafast time-resolved fluorescence measurements at a range of excitation and detection wavelengths suggest rapid (and hence efficient) energy transfer from the dendron to the core. Ultrafast fluorescence anisotropy decay for different dendrimer generations is described in order to probe the energy migration processes. A femtosecond time-scale fluorescence depolarization was observed with the zero and second generation dendrimers. Energy transfer process from the dendrons to the core can be described by a Förster mechanism (hopping dynamics) while the interbranch interaction in A-DSB core was found to be very strong indicating the crossover to exciton dynamics
Hormone replacement therapy after surgery for stage 1 or 2 cutaneous melanoma
A total of 206 women were followed for a minimum of 5 years after primary melanoma surgery to establish if hormone replacement therapy (HRT) adversely affected prognosis. In all, 123 had no HRT and 22 have died of melanoma; 83 had HRT for varying periods and one has died of melanoma. After controlling for known prognostic factors, we conclude that HRT after melanoma does not adversely affect prognosis
Assessment of the face validity, feasibility and utility of a patient-completed questionnaire for polymyalgia rheumatica: a postal survey using the QQ-10 questionnaire.
BACKGROUND: The development of a patient-reported outcome measure (PROM) for polymyalgia rheumatica (PMR), a condition that causes pain, stiffness and disability, is necessary as there is no current validated disease-specific measure. Initial literature synthesis and qualitative research established a conceptual framework for the condition along with a list of symptoms and effects of PMR that patients felt were important to them. These findings were used to derive the candidate items for a patient-completed questionnaire. We aim to establish the face validity of this initial "long form" of a PROM. METHODS: People with a current or previous diagnosis of PMR were recruited both from the community and from rheumatology clinics. They were asked to complete the PMR questionnaire along with the QQ-10 questionnaire, which is a measure used to assess the face validity, feasibility and utility of patient healthcare questionnaires. RESULTS: A total of 28 participants with an age range of 59-85 years and a length of time since diagnosis from 4 months to 18 years completed the QQ-10. The overall mean "value" score was 79% (SD 12), and the mean "burden" score was 21% (SD 18). The free-text comments were analysed thematically and were found to focus on layout, content, where in the clinical pathway the questionnaire would be most beneficial, specific items missing and other areas for consideration. CONCLUSIONS: The high mean value score and low burden score indicate that the questionnaire has good face validity and is acceptable to patients. The questionnaire now needs to undergo further psychometric evaluation and refinement to develop the final tool for use in clinical practice and research
Feshbach resonances and collapsing Bose-Einstein condensates
We investigate the quantum state of burst atoms seen in the recent Rb-85
experiments at JILA. We show that the presence of a resonance scattering state
can lead to a pairing instability generating an outflow of atoms with energy
comparable to that observed. A resonance effective field theory is used to
study this dynamical process in an inhomogeneous system with spherical
symmetry
Anti-Platelet Aggregation and Anti-Cyclooxygenase Activities for a Range of Coffee Extracts (Coffea arabica)
Coffee is rich in caffeine (CF), chlorogenic acid (CGA) and phenolics. Differing types of coffee beverages and brewing procedures may result in differences in total phenolic contents (TPC) and biological activities. Inflammation and increases of platelet activation and aggregation can lead to thrombosis. We focused on determining the chemical composition, antioxidant activity and inhibitory effects on agonist-induced platelet aggregation and cyclooxygenase (COX) of coffee beverages in relation to their preparation method. We prepared instant coffee and brewed coffee beverages using drip, espresso, and boiling techniques. Coffee extracts were assayed for their CF and CGA contents using HPLC, TPC using colorimetry, platelet aggregation with an aggregometer, and COX activity using ELISA. The findings have shown all coffee extracts, except the decaffeinated types, contained nearly equal amounts of CF, CGA, and TPC. Inhibitory effects of coffee extracts on platelet aggregation differed depending on the activation pathways induced by different agonists. All espresso, drip and boiled coffee extracts caused dose dependent inhibition of platelet aggregation induced by ADP, collagen, epinephrine, and arachidonic acid (ARA). The most marked inhibition was seen at low doses of collagen or ARA. Espresso and drip extracts inhibited collagen-induced platelet aggregation more than purified caffeine or CGA. Espresso, boiled and drip coffee extracts were also a more potent inhibitors of COX-1 and COX-2 than purified caffeine or CGA. We conclude that inhibition of platelet aggregation and COX-1 and COX-2 may contribute to anti-platelet and anti-inflammatory effects of espresso and drip coffee extracts
Dissipative Particle Dynamics with Energy Conservation
The stochastic differential equations for a model of dissipative particle
dynamics with both total energy and total momentum conservation in the
particle-particle interactions are presented. The corresponding Fokker-Planck
equation for the evolution of the probability distribution for the system is
deduced together with the corresponding fluctuation-dissipation theorems
ensuring that the ab initio chosen equilibrium probability distribution for the
relevant variables is a stationary solution. When energy conservation is
included, the system can sustain temperature gradients and heat flow can be
modeled.Comment: 7 pages, submitted to Europhys. Let
Superposition of macroscopic numbers of atoms and molecules
We theoretically examine photoassociation of a non-ideal Bose-Einstein
condensate, focusing on evidence for a macroscopic superposition of atoms and
molecules. This problem raises an interest because, rather than two states of a
given object, an atom-molecule system is a seemingly impossible macroscopic
superposition of different objects. Nevertheless, photoassociation enables
coherent intraparticle conversion, and we thereby propose a viable scheme for
creating a superposition of a macroscopic number of atoms with a macroscopic
number of molecules.Comment: 4 pages, 2 figs, to appear in Phys. Rev. Let
Exploring Droughts and Floods and Their Association with Cholera Outbreaks in Sub-Saharan Africa:A Register-Based Ecological Study from 1990 to 2010
- âŠ