10 research outputs found
3-D printed band-pass combline filter
This article describes a fourth-order 3-D printed combline filter with a Chebyshev response, operating at central frequency 3 GHz and having a 3% fractional bandwidth. The filter is designed using the coupling matrix theory, fabricated, and experimental results are presented. Comparison between simulations and measurements shows good agreement
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Effect of ultrapure lipopolysaccharides derived from diverse bacterial species on the modulation of platelet activation
Platelets are small circulating blood cells that play essential roles in the maintenance of haemostasis via blood clotting. However, they also play critical roles in the regulation of innate immune responses. Inflammatory receptors, specifically Toll-like receptor (TLR)-4, have been reported to modify platelet reactivity. A plethora of studies have reported controversial functions of TLR4 in the modulation of platelet function using various chemotypes and preparations of its ligand, lipopolysaccharide (LPS). The method of preparation of LPS may explain these discrepancies however this is not fully understood. Hence, to determine the impact of LPS on platelet activation, we used ultrapure preparations of LPS from Escherichia coli (LPSEC), Salmonella minnesota (LPSSM), and Rhodobacter sphaeroides (LPSRS) and examined their actions under diverse experimental conditions in human platelets. LPSEC did not affect platelet activation markers such as inside-out signalling to integrin IIb3 or P-selectin exposure upon agonist-induced activation in platelet-rich plasma or whole blood whereas LPSSM and LPSRS inhibited platelet activation under specific conditions at supraphysiological concentrations. Overall, our data demonstrate that platelet activation is not largely influenced by any of the ultrapure LPS chemotypes used in this study on their own except under certain conditions
Structure-activity relationship (SAR) in monosaccharide-based Toll-like receptor 4 (TLR4) antagonists
The structure-activity relationship was investigated in a series of synthetic TLR4 antagonists formed by a glucosamine core linked to two phosphate esters and two linear carbon chains. Molecular modeling showed that the compounds with 10, 12 and 14 carbons chains are associated to higher stabilization of the MD-2/TLR4 antagonist conformation than in the case of the C16 variant. Binding experiments with human MD-2 showed that the C12 and C14 variants have higher affinity than C10, while the C16 variant did not interact with the protein.
The molecules, with the exception of the C16 variant, inhibited the LPS-stimulated TLR4 signal in human and murine cells and the antagonist potency mirrored the MD-2 affinity calculated from in vitro binding experiments. FT-IR, NMR, and SAXS measurements suggested that the aggregation state in aqueous solution depends on fatty acid chains lengths and that this property can influence TLR4 activity in this series of compounds
Feasibility of a prehabilitation programme dedicated to older patients with cancer before complex medical–surgical procedures: the PROADAPT pilot study protocol
Background Ageing is associated with an increased prevalence of comorbidities and sarcopenia as well as a decline of functional reserve of multiple organ systems, which may lead, in the context of the disease-related and/or treatment-related stress, to functional deconditioning. The multicomponent ‘Prehabilitation & Rehabilitation in Oncogeriatrics: Adaptation to Deconditioning risk and Accompaniment of Patients’ Trajectories (PROADAPT)’ intervention was developed multiprofessionally to implement prehabilitation in older patients with cancer.Methods The PROADAPT pilot study is an interventional, non-comparative, prospective, multicentre study. It will include 122 patients oriented to complex medical–surgical curative procedures (major surgery or radiation therapy with or without chemotherapy). After informed consent, patients will undergo a comprehensive geriatric assessment and will be offered a prehabilitation kit that includes an advice booklet with personalised objectives and respiratory rehabilitation devices. Patients will then be called weekly and monitored for physical and respiratory rehabilitation, preoperative renutrition, motivational counselling and iatrogenic prevention. Six outpatient visits will be planned: at inclusion, a few days before the procedure and at 1, 3, 6 and 12 months after the end of the procedure. The main outcome of the study is the feasibility of the intervention, defined as the ability to perform at least one of the components of the programme. Clinical data collected will include patient-specific and cancer-specific characteristics.Ethics and dissemination The study protocol was approved by the Ile de France 8 ethics committee on 5 June 2018. The results of the primary and secondary objectives will be published in peer-reviewed journals.Trial registration number NCT03659123. Pre-results of the trial