1,679 research outputs found

    Multimodal Imaging of Autofluorescent Sites Reveals Varied Chemical Speciation in SSZ-13 Crystals

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    A multimodal imaging study of chabazite is used to show the distribution of and discriminate between different emissive deposits arising as a result of the detemplation process. Confocal imaging, 3D fluorescence lifetime imaging, 3D multispectral fluorescence imaging, and Raman mapping are used to show three different types of emissive behaviours each characterised by different spatial distributions, trends in lifetime, spectral signals, and Raman signatures. A notable difference is seen in the morphology of agglomerated surface deposits and larger subsurface deposits, which experience lifetime augmentation due to spatial confinement. The distribution of organic residue throughout the crystal volume is comparable to XRF mapping that shows Si enrichment on the outer edges and higher Al content through the centre, demonstrating that a fluorescence‐based technique can also be used to indirectly comment on the compositional chemistry of the inorganic framework

    A Multimodal Label-Free Imaging Study of Zeolite Crystals

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    Zeolites are complex materials that are widely employed in industry as heterogenous catalysts. Their unique open framework structures allow them to not only act as size-selective sieves, but to play host to an adsorbed phase of organic guest molecules. Imaging both the framework and the concomitant adsorbed organic material in a single micrograph is very challenging because each material has different requirements for generating image contrast. In particular, chemically interesting organic material is hard to see using electron imaging techniques that otherwise resolve the framework relatively successfully

    Enhancement of Noise-induced Escape through the Existence of a Chaotic Saddle

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    We study the noise-induced escape process in a prototype dissipative nonequilibrium system, the Ikeda map. In the presence of a chaotic saddle embedded in the basin of attraction of the metastable state, we find the novel phenomenon of a strong enhancement of noise-induced escape. This result is established by employing the theory of quasipotentials. Our finding is of general validity and should be experimentally observable.Comment: 4 page

    Lymph node core biopsies reliably permit diagnosis of lymphoproliferative diseases. Real‐World Experience from 554 sequential core biopsies from a single centre

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    INTRODUCTION: Whilst excision biopsy is traditionally preferred, advances in radiological and histological techniques warrant a re-look at core biopsy as a viable primary diagnostic method. METHOD: Over a 3-year period, all patients who underwent core biopsy to investigate lymphoma at our centre were included. RESULTS: 554 consecutive patients were included (40.1% prior lymphoma and 59.4% new presentations). Three or more cores were taken in 420 (75.8%) cases. Median time from request to biopsy and biopsy to histology report was 2 (0-40) days and 7 (1-24) days respectively. 510/544 (93.8%) biopsies were diagnostic. There was no difference in whether the biopsy was diagnostic based on indication (new vs. relapsed lymphoma) (p=0.445), whether biopsy was PET-directed (p=0.507), for T-cell lymphoma (p=0.468) or nodal vs. extra-nodal (p=0.693). Thirty-eight patients (6.9%) required a second biopsy due to inadequate tissue. In a patient experience survey, only 13.9% reported any complications (1 self-limiting minor bleeding, 4 bruising) whilst 16.7% reported any discomfort beyond 12 hours. CONCLUSION: Core biopsy performed by experienced radiologists and analysed by expert haemato-pathologists is a reliable, well-tolerated method for diagnosing lymphoma and confirming relapse. Multiple cores can be obtained under local anaesthetic yielding sufficient material in the majority of cases

    A Randomized Controlled Trial of Extended Brief Intervention for Alcohol-Dependent Patients in an Acute Hospital Setting

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    To determine whether alcohol-dependent patients in a hospital setting benefit from extended brief interventions (EBI) delivered by an Alcohol Specialist Nurse. Methods Alcohol-dependent patients recruited via screening at the emergency department (ED) (n = 267), whether or not admitted to hospital, were randomized to EBI (up to six counselling sessions offered) or control. At 6 months, 84.2% of patients were assessed by a researcher blinded to the intervention. The primary outcome was a fall in Severity of Alcohol Dependence Questionnaire. Results There was no difference between groups in the primary outcome [odds ratio (OR) 1.02; 95% confidence interval (CI): 0.38, 2.75, P = 0.97]. Secondary outcomes including alcohol consumption and readiness to change did not show a significant difference between groups. However, all secondary outcome measures improved, on average, in both arms. Conclusions Although EBI can be delivered in an ED or inpatient setting, it was not shown to be an advantage over screening and usual management (which included advice on alternative services), with patients in both groups showing an average improvement

    The promoter polymorphism -232C/G of the PCK1 gene is associated with type 2 diabetes in a UK-resident South Asian population

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    Background: The PCK1 gene, encoding cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C), has previously been implicated as a candidate gene for type 2 diabetes (T2D) susceptibility. Rodent models demonstrate that over-expression of Pck1 can result in T2D development and a single nucleotide polymorphism (SNP) in the promoter region of human PCK1 (-232C/G) has exhibited significant association with the disease in several cohorts. Within the UK-resident South Asian population, T2D is 4 to 6 times more common than in indigenous white Caucasians. Despite this, few studies have reported on the genetic susceptibility to T2D in this ethnic group and none of these has investigated the possible effect of PCK1 variants. We therefore aimed to investigate the association between common variants of the PCK1 gene and T2D in a UK-resident South Asian population of Punjabi ancestry, originating predominantly from the Mirpur area of Azad Kashmir, Pakistan. \ud \ud Methods: We used TaqMan assays to genotype five tagSNPs covering the PCK1 gene, including the -232C/G variant, in 903 subjects with T2D and 471 normoglycaemic controls. \ud \ud Results: Of the variants studied, only the minor allele (G) of the -232C/G SNP demonstrated a significant association with T2D, displaying an OR of 1.21 (95% CI: 1.03 - 1.42, p = 0.019). \ud \ud Conclusion: This study is the first to investigate the association between variants of the PCK1 gene and T2D in South Asians. Our results suggest that the -232C/G promoter polymorphism confers susceptibility to T2D in this ethnic group. \ud \ud Trial registration: UKADS Trial Registration: ISRCTN38297969
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