589 research outputs found
Integrability of Lie systems through Riccati equations
Integrability conditions for Lie systems are related to reduction or
transformation processes. We here analyse a geometric method to construct
integrability conditions for Riccati equations following these approaches. This
approach provides us with a unified geometrical viewpoint that allows us to
analyse some previous works on the topic and explain new properties. Moreover,
this new approach can be straightforwardly generalised to describe
integrability conditions for any Lie system. Finally, we show the usefulness of
our treatment in order to study the problem of the linearisability of Riccati
equations.Comment: Corrected typo
MMP-1 activation contributes to airway smooth muscle growth and asthma severity
Introduction: Matrix metalloproteinase-1 and mast cells are present in the airways of people with asthma. We hypothesised that matrix metalloproteinase-1 could be activated by mast cells and increase asthma severity. Methods: Patients with stable asthma and healthy controls underwent spirometry, methacholine challenge, bronchoscopy and their airway smooth muscle cells were grown in culture. A second asthma group and controls had symptom scores, spirometry and bronchoalveolar lavage before and after rhinovirus-induced asthma exacerbations. Extra-cellular matrix was prepared from decellularised airway smooth muscle cultures. Matrix metalloproteinase-1 protein and activity were assessed. Results: Airway smooth muscle cells generated pro-matrix metalloproteinase-1 which was proteolytically activated by mast cell tryptase. Airway smooth muscle treated with activated mast cell supernatants produced extra-cellular matrix which enhanced subsequent airway smooth muscle growth by 1.5 fold (p<0.05) which was dependent on matrix metalloproteinase-1 activation. In asthma, airway pro-matrix metalloproteinase-1 was 5.4 fold higher than control subjects (p=0.002). Mast cell numbers were associated with airway smooth muscle proliferation and matrix metalloproteinase-1 protein associated with bronchial hyper-responsiveness. During exacerbations, matrix metalloproteinase-1 activity increased and was associated with fall in FEV1 and worsening asthma symptoms. Conclusions: Matrix metalloproteinase-1 is activated by mast cell tryptase resulting in a pro-proliferative extra-cellular matrix. In asthma, mast cells are associated with airway smooth muscle growth, matrix metalloproteinase-1 levels are associated with bronchial hyper-responsiveness and matrix metalloproteinase-1 activation with exacerbation severity. Our findings suggest that airway smooth muscle/mast cell interactions contribute to asthma severity by transiently increasing matrix metalloproteinase activation, airway smooth muscle growth and airway responsiveness
Women's views and experiences of two alternative consent pathways for participation in a preterm intrapartum trial: a qualitative study
BACKGROUND: The Cord Pilot Trial compared alternative policies for timing of cord clamping at very preterm birth at eight UK hospitals. In addition to standard written consent, an oral assent pathway was developed for use when birth was imminent. The aim of this study was to explore women's views and experiences of two alternative consent pathways to participate in the Cord Pilot Trial.
METHODS: We conducted a qualitative study using semi-structured interviews. A total of 179 participants in the Cord Pilot Trial were sent a postal invitation to take part in interviews. Women who agreed were interviewed in person or by telephone to explore their experiences of two consent pathways for a preterm intrapartum trial. Data were analysed using inductive systematic thematic analysis.
RESULTS: Twenty-three women who gave either written consent (n = 18) or oral assent followed by written consent (n = 5) to participate in the trial were interviewed. Five themes were identified: (1) understanding of the implications of randomisation, (2) importance of staff offering participation, (3) information about the trial and time to consider participation, (4) trial secondary in women's minds and (5) reasons for agreeing to take part in the trial. Experiences were similar for the two consent pathways. Women recruited by the oral assent pathway reported being given less information about the trial but felt it was sufficient to make a decision regarding participation. There were gaps in women's understanding of the trial and intervention, regardless of the consent pathway.
CONCLUSIONS: Overall, women were positive about their experiences of being invited to participate in the trial. The oral assent pathway seems an acceptable option for women if the intervention is low-risk and time is limited.
TRIAL REGISTRATION: ISRCTN Registry, ISRCTN21456601 . Registered on 28 February 2013
Electrospinning applications in sustainable agriculture: Enhancing soil health, seed coatings and post-harvest antimicrobial protection
Nanotechnology holds significant potential in agriculture, contributing to various applications such as nanofertilizers, nanopesticides, nanoherbicides, nanosensors and more recently, electrospun nanofibers. Among such advancements, electrospinning has emerged as a versatile and cost-effective technique for fabricating nanofibers, offering significant potential to enhance sustainability in agricultural practices. Recent applications of electrospun fibers have primarily focused on drug delivery, wound dressings and seed coatings infused with growth hormones. These nanofibers exhibit notable properties such as a high surface-area-to-volume ratio, excellent porosity and the ability to facilitate controlled release of active compounds. Encapsulating microorganisms and agrochemicals within electrospun fibers offers an environmentally friendly approach to improve soil health. By forming a protective layer, the electrospun nanofibers help safeguard seeds against abiotic factors such as drought and temperature fluctuations, as well as biotic threats like pathogens and pests. Furthermore, embedding natural or synthetic antimicrobial agents into electrospun films offers an eco-friendly solution for post-harvest protection by effectively minimizing spoilage and the risk of pathogen invasion. This review emphasizes the diverse roles of electrospun nanofibers in sustainable agriculture, including soil enhancement, seed improvement and post-harvest protection, while also promoting eco-friendly practices using biodegradable polymers and bioactive agents
Picture free recall performance linked to the brain's structural connectome
Memory functions are highly variable between healthy humans. The neural correlates of this variability remain largely unknown.; Here, we investigated how differences in free recall performance are associated with DTI-based properties of the brain's structural connectome and with grey matter volumes in 664 healthy young individuals tested in the same MR scanner.; Global structural connectivity, but not overall or regional grey matter volumes, positively correlated with recall performance. Moreover, a set of 22 inter-regional connections, including some with no previously reported relation to human memory, such as the connection between the temporal pole and the nucleus accumbens, explained 7.8% of phenotypic variance.; In conclusion, this large-scale study indicates that individual memory performance is associated with the level of structural brain connectivity
Satisfaction with the oral health services. A qualitative study among non-commissioned officers in the Malaysian armed forces
Patient satisfaction is critical for the growth and prosperity of any oral health service or practice. The success of any oral health service can be assessed by an evaluation of the degree of satisfaction/dissatisfaction of its patients. Objective The aim of this study is to assess satisfaction/dissatisfaction with the oral health services among Non-Commissioned Officers (NCOs) in the Malaysian Armed Forces (MAF). Method A qualitative study using the Nominal Group Technique was undertaken. Eighty subjects from the Rasah Camp, Seremban were randomly selected from four lists, namely privates, male and female corporals and sergeants and were Grouped into 10 discussion groups of eight participants each. Of the 10 groups, four groups comprised male corporals.. three groups of privates, two groups of sergeants and one group of female corporals. Two separate discussion sessions were conducted to elicit factors/items causing dissatisfaction and satisfaction expressed by the participants. Every participant then scored all the factors perceived as important by members of the group. The score ranged from 0-9 i.e., the least to the most important. Scores were weighted, and the weighted score of every participant for each item was added. The ratings of the factors were determined by comparing the sum Of the weighted scores. Results The six most important factors/items rated in the satisfaction discussion were modern equipment (9.07), friendly dentist (8.27), pleasant surgery (8.23), good quality treatment (7.93), friendly staff (7.18) and pain alleviation (6.07). These factors were further regrouped into three broad categories i.e. (1) Clinic set-Lip, (2) Patient-personnel interaction (PPI) and (3) Technical competency (TC). In the dissatisfaction discussion six factors/items were rated i.e. long waiting time (10.39), sequence of treatment not followed (7.18), non-availability of dentist (7.16), unfriendly staff (7.05), poor quality treatment (6.80) and restricted time for treatment (5.98). The three most important categories in the dissatisfaction discussion were (1) Administrative efficiency, (2) PPI and (3) TC. Conclusion A conceptual model was developed to explain the factors affecting patients' satisfaction/dissatisfaction with the oral health services. It is recommended that a questionnaire Survey be undertaken to validate and reflect the entire population of the MAF. Remedial measures highlighted in the areas of dissatisfaction should be addressed accordingly based on the quantitative study
Mapping on slope seepage problem using Electrical Resistivity Imaging (ERI)
The stability of slope may influenced by several factors such as its geomaterial properties, geometry and environmental factors. Problematic slope due to seepage phenomenon will influenced the slope strength thus promoting to its failure. In the past, slope seepage mapping suffer from several limitation due to cost, time and data coverage. Conventional engineering tools to detect or mapped the seepage on slope experienced those problems involving large and high elevation of slope design. As a result, this study introduced geophysical tools for slope seepage mapping based on electrical resistivity method. Two spread lines of electrical resistivity imaging were performed on the slope crest using ABEM SAS 4000 equipment. Data acquisition configuration was based on long and short arrangement, schlumberger array and 2.5 m of equal electrode spacing interval. Raw data obtained from data acquisition was analyzed using RES2DINV software. Both of the resistivity results show that the slope studied consists of three different anomalies representing top soil (200 – 1000 Ωm), perched water (10 – 100 Ωm) and hard/dry layer (> 200 Ωm). It was found that seepage problem on slope studied was derived from perched water zones with electrical resistivity value of 10 – 100 Ωm. Perched water zone has been detected at 6 m depth from the ground level with varying thickness at 5 m and over. Resistivity results have shown some good similarity output with reference to borehole data, geological map and site observation thus verified the resistivity results interpretation. Hence, this study has shown that the electrical resistivity imaging was applicable in slope seepage mapping which consider efficient in term of cost, time, data coverage and sustainability
Extra-cellular matrix proteins induce matrix metalloproteinase-1 (MMP-1) activity and increase airway smooth muscle contraction in asthma
Airway remodelling describes the histopathological changes leading to fixed airway obstruction in patients with asthma and includes extra-cellular matrix (ECM) deposition. Matrix metalloproteinase-1 (MMP-1) is present in remodelled airways but its relationship with ECM proteins and the resulting functional consequences are unknown. We used airway smooth muscle cells (ASM) and bronchial biopsies from control donors and patients with asthma to examine the regulation of MMP-1 by ECM in ASM cells and the effect of MMP-1 on ASM contraction. Collagen-I and tenascin-C induced MMP-1 protein expression, which for tenascin-C, was greater in asthma derived ASM cells. Tenascin-C induced MMP-1 expression was dependent on ERK1/2, JNK and p38 MAPK activation and attenuated by function blocking antibodies against the β1 and β3 integrin subunits. Tenascin-C and MMP-1 were not expressed in normal airways but co-localised in the ASM bundles and reticular basement membrane of patients with asthma. Further, ECM from asthma derived ASM cells stimulated MMP-1 expression to a greater degree than ECM from normal ASM. Bradykinin induced contraction of ASM cells seeded in 3D collagen gels was reduced by the MMP inhibitor ilomastat and by siRNA knockdown of MMP-1. In summary, the induction of MMP-1 in ASM cells by tenascin-C occurs in part via integrin mediated MAPK signalling. MMP-1 and tenascin-C are co-localised in the smooth muscle bundles of patients with asthma where this interaction may contribute to enhanced airway contraction. Our findings suggest that ECM changes in airway remodelling via MMP-1 could contribute to an environment promoting greater airway narrowing in response to broncho-constrictor stimuli and worsening asthma symptoms
Evaluating the effect of steroids on the incidence of reintubation rates in children with laryngotracheobronchitis
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