70 research outputs found
Airblast atomization : the effect of linear scale on the mean drop size
Stationary prefilming-cup airblast atomizers, in
which the fuel is first spread into a thin cylindrical
sheet and then exposed on both sides to high velocity
air, have several important advantages over other common
methods of fuel injection in their application to
continuous combustion systems.
This thesis reports the results of a detailed
programme of research on airblast atomization directed
primarily to the investigation of the effect of atomizer
linear scale, or size, on the mean drop diameter of
sprays and, to the provision of a comprehensive picture
of the performance of thin-sheet airblast atomizers over
a wide range of working conditions. Three geometrically
similar atomizers giving cross-sectional areas in the
ratio of 1 : 4 : 16 were used; covering the range of
prefilming cup diameter, D, from 19.05mm. to 76.20
millimeters, and were capable of handling various liquids
at flow rates from 0.003kg/s up to 0.225 kg/s, at fuel
pressures below 33 x 10^ N/m^ (about 50 p.s.i.). .
It was found that atomizer scale has an appreciable
direct effect on atomization quality. The Sauter mean
diameter of low liquid viscosity sprays increases with
the 0.44 power of atomizer linear dimension (D), while
for liquids of high viscosity this effect is slightly higher.Ph
Consensus evidence-based recommendations for treat-to-target management of immunoglobulin A vasculitis
IgA vasculitis (IgAV), formerly known as Henoch-Schönlein purpura, is the most common cause of systemic vasculitis in childhood. Given its potential life-threatening systemic
complications, early and accurate diagnosis as well as management of IgAV represent a major challenge for health care professionals. This study was carried out to attain an evidence-based expert consensus on a treat-to-target management approach for IgAV using Delphi technique.
The preliminary scientific committee identified a total of 16 key clinical questions according to the patient, intervention, comparison, and outcomes (PICO) approach. An evidence-based, systematic, literature review was conducted to compile evidence for the IgAV management.
The core leadership team identified researchers and clinicians with expertise in IgAV management in Egypt upon which experts were gathered from different governorates and health centers across Egypt. Delphi process was implemented (two rounds) to reach a consensus. An online questionnaire was sent to expert panel (n = 26) who participated in the two rounds. After completing round 2, a total of 20 recommendation items, categorized into two sections were
obtained. Agreement with the recommendations (rank 7–9) ranged from 91.7–100%.
Consensus was reached (i.e. ⩾75% of respondents strongly agreed or agreed) on the wording of all the 20 clinical standards identified by the scientific committee. Algorithms for the diagnosis and management have been suggested. This was an expert, consensus recommendations for the diagnosis and treatment of IgAV and IgA vasculitic nephritis, based on best available evidence and expert opinion. The guideline presented a strategy of care with a pathway to achieve a state of remission as early as possible
Chronic urticaria in the real‐life clinical practice setting in the UK: results from the non‐interventional multicentre AWARE study
Abstract
Background
Chronic urticaria (CU) is a skin condition characterised by repeated occurrence of itchy wheals and/or angioedema for >6 weeks.
Aim
To provide data demonstrating the real‐life burden of CU in the UK.
Methods
This UK subset of the worldwide, prospective, non‐interventional AWARE study included patients aged 18–75 years diagnosed with H1‐antihistamine (H1‐AH)‐refractory chronic spontaneous urticaria (CSU) for >2 months. Baseline characteristics, disease activity, treatments, comorbidities and healthcare resource use were documented. Quality of life, work productivity and activity impairment were assessed.
Results
Baseline analysis included 252 UK patients. Mean age and body mass index were 45.0 years and 29.0 kg/m2, respectively. Most patients were female (77.8%) and had moderate/severe disease activity (mean Urticaria Activity Score over 7 days, 18.4) and a ‘spontaneous’ component to their CU (73.4% CSU; 24.6% CSU and chronic inducible urticaria). Common comorbidities included depression/anxiety (24.6%), asthma (23.8%) and allergic rhinitis (12.7%). A previous treatment was recorded for 57.9% of patients. Mean Dermatology Life Quality Index score was 9.5 and patients reported impairments in work productivity and activity. Healthcare resource use was high. Severity of CSU was associated with gender, obesity, anxiety and diagnosis. Only 28.5% of patients completed all nine study visits, limiting analysis of long‐term treatment patterns and disease impact.
Conclusions
Adult H1‐AH‐refractory CU patients in the UK reported high rates of healthcare resource use and impairment in quality of life, work productivity and activity at baseline. The differing structures of UK healthcare may explain the high study discontinuation rates versus other countries
Complexity of case mix in a regional allergy service
<p>Abstract</p> <p>Background</p> <p>Currently in the United Kingdom (UK), there is a mismatch between limited financial resources and the large proportion of patients with suspected allergies actually being referred to specialist allergy clinics. To better understand the case mix of patients being referred, we audited referrals to a regional allergy service over an 8 year period.</p> <p>The main source of data was consultant letters to General Practitioners (GP) summarising the diagnosis of patients, archived from January 2002 to September 2009. Letters were reviewed, extracting the clinic date, doctor seen, gender, date of birth, postcode, GP, and diagnoses. Diagnoses were classified into seven groups and illustrative cases for each group noted.</p> <p>Findings</p> <p>Data from 2,028 new referrals with suspected allergy were analysed. The largest group of patients (43%) were diagnosed with a type I hypersensitivity. The other diagnostic groups were chronic idiopathic (spontaneous) urticaria (35%), suspected type I hypersensitivity but no allergen identified (8%), idiopathic (spontaneous) angioedema (8%), physical urticaria (2.5%), non-allergic symptoms (1.6%), type IV hypersensitivity (0.8%) and ACE inhibitor sensitivity (0.5%). Two thirds of patients seen were female with a higher percentage of female patients in the non type-I hypersensitivity group (71%) than the type 1 hypersensitivity (66%) (χ<sup>2 </sup>= 5.1, 1df, <it>p = 0.024</it>). The type 1 hypersensitivity patients were younger than other patients (38 Vs 46 years, t = -10.8, <it>p < 0.001</it>)</p> <p>Conclusions</p> <p>This study highlights the complexity of specialist allergy practice and the large proportion of patients referred with non-type I hypersensitivities, chronic idiopathic (spontaneous) urticaria being by far the largest group. Such information is critical to inform commissioning decisions, define referral pathways and in primary care education.</p
CD4(+)CD25(+)FOXP3(+) Regulatory T Cells Suppress Anti-Tumor Immune Responses in Patients with Colorectal Cancer
BACKGROUND: A wealth of evidence obtained using mouse models indicates that CD4(+)CD25(+)FOXP3(+) regulatory T cells (Treg) maintain peripheral tolerance to self-antigens and also inhibit anti-tumor immune responses. To date there is limited information about CD4(+) T cell responses in patients with colorectal cancer (CRC). We set out to measure T cell responses to a tumor-associated antigen and examine whether Treg impinge on those anti-tumor immune responses in CRC patients. METHODOLOGY AND PRINCIPAL FINDINGS: Treg were identified and characterized as CD4(+)CD25(+)FOXP3(+) using flow cytometry. An increased frequency of Treg was demonstrated in both peripheral blood and mesenteric lymph nodes of patients with colorectal cancer (CRC) compared with either healthy controls or patients with inflammatory bowel disease (IBD). Depletion of Treg from peripheral blood mononuclear cells (PBMC) of CRC patients unmasked CD4(+) T cell responses, as observed by IFNγ release, to the tumor associated antigen 5T4, whereas no effect was observed in a healthy age-matched control group. CONCLUSIONS/SIGNIFICANCE: Collectively, these data demonstrate that Treg capable of inhibiting tumor associated antigen-specific immune responses are enriched in patients with CRC. These results support a rationale for manipulating Treg to enhance cancer immunotherapy
Loss of function NFKB1 variants are the most common monogenic cause of CVID in Europeans.
BACKGROUND: The genetic etiology of primary immunodeficiency disease (PID) carries prognostic information. OBJECTIVE: We conducted a whole-genome sequencing study assessing a large proportion of the NIHR-BioResource - Rare Disease cohort. METHODS: In the predominantly European study population of principally sporadic unrelated PID cases (n=846), a novel Bayesian method identified NFKB1 as one most strongly associated with PID, and the association was explained by 16 novel heterozygous truncating, missense and gene deletion variants. This accounted for 4% of common variable immunodeficiency (CVID) cases (n=390) in the cohort. Amino-acid substitutions predicted to be pathogenic were assessed by analysis of structural protein data. Immunophenotyping, immunoblotting and ex vivo stimulation of lymphocytes determined the functional effects of these variants. Detailed clinical and pedigree information was collected for genotype-phenotype co-segregation analyses. RESULTS: Both sporadic and familial cases demonstrated evidence of the non-infective complications of CVID, including massive lymphadenopathy (24%), unexplained splenomegaly (48%) and autoimmune disease (48%), features prior studies correlate with worse clinical prognosis. Although partial penetrance of clinical symptoms was noted in certain pedigrees, all carriers have a deficiency in B lymphocyte differentiation. Detailed assessment of B lymphocyte numbers, phenotype and function identifies the presence of a raised CD21lowB cell population: combined with identification of the disease-causing variant, this distinguishes between healthy individuals, asymptomatic carriers and clinically affected cases. CONCLUSION: We show that heterozygous loss-of-function variants in NFKB1 are the most common known monogenic cause of CVID that results in a temporally progressive defect in the formation of immunoglobulin-producing B cells.This study was supported by The National Institute for Health Research England (grant number RG65966), and by the Center of Immunodeficiencies Amsterdam (CIDA). JET is supported by an MRC Clinician Scientist Fellowship (MR/L006197/1). AJT is supported by both the Wellcome Trust (104807/Z/14/Z) and by the National Institute for Health Research Biomedical Research Centre at Great Ormond Street Hospital for Children NHS Foundation Trust and University College London. EO receives personal fees from CSL Behring and MSD
Autosomal dominant STAT6 Gain of function causes severe atopy associated with lymphoma
The transcription factor STAT6 (Signal Transducer and Activator of Transcription 6) is a key regulator of Th2 (T-helper 2) mediated allergic inflammation via the IL-4 (interleukin-4) JAK (Janus kinase)/STAT signalling pathway. We identified a novel heterozygous germline mutation STAT6 c.1255G > C, p.D419H leading to overactivity of IL-4 JAK/STAT signalling pathway, in a kindred affected by early-onset atopic dermatitis, food allergy, eosinophilic asthma, anaphylaxis and follicular lymphoma. STAT6 D419H expression and functional activity were compared with wild type STAT6 in transduced HEK293T cells and to healthy control primary skin fibroblasts and peripheral blood mononuclear cells (PBMC). We observed consistently higher STAT6 levels at baseline and higher STAT6 and phosphorylated STAT6 following IL-4 stimulation in D419H cell lines and primary cells compared to wild type controls. The pSTAT6/STAT6 ratios were unchanged between D419H and control cells suggesting that elevated pSTAT6 levels resulted from higher total basal STAT6 expression. The selective JAK1/JAK2 inhibitor ruxolitinib reduced pSTAT6 levels in D419H HEK293T cells and patient PBMC. Nuclear staining demonstrated increased STAT6 in patient fibroblasts at baseline and both STAT6 and pSTAT6 after IL-4 stimulation. We also observed higher transcriptional upregulation of downstream genes (XBP1 and EPAS1) in patient PBMC. Our study confirms STAT6 gain of function (GOF) as a novel monogenetic cause of early onset atopic disease. The clinical association of lymphoma in our kindred, along with previous data linking somatic STAT6 D419H mutations to follicular lymphoma suggest that patients with STAT6 GOF disease may be at higher risk of lymphomagenesis
Orthogonal double cover of Complete Bipartite Graph by disjoint union of complete bipartite graphs
Let H be a graph on n vertices and G a collection of n subgraphs of H, one for each vertex, G is an orthogonal double cover (ODC) of H if every edge of H occurs in exactly two members of G and any two members share an edge whenever the corresponding vertices are adjacent in H and share no edges whenever the corresponding vertices are nonadjacent in H. In this paper, we are concerned with symmetric starter vectors of the orthogonal double covers (ODCs) of the complete bipartite graph and using the method of cartesian product of symmetric starter vectors to construct ODC of the complete bipartite graph by G, where G is a complete bipartite graph, disjoint union of different complete bipartite graphs and disjoint union of finite copies of a complete bipartite graph
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