549 research outputs found

    H2 detection mechanism in chemoresistive sensor based on low-cost synthesized WO3 nanorods

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    Abstract Nanostructured WO3 represents a promising material for fast and reliable molecular hydrogen detection through chemo-resistive effect. Here, an extended experimental investigation of WO3-H2 interaction is presented and modeled. A powder of WO3 nanorods (400 nm long, 50 nm large) is produced by hydrothermal technique and drop casted on Pt interdigitated electrode. H2 sensing tests at different concentrations (2000–50,000 ppm) and temperatures (250–400 °C) are reported. Scanning Electron Microscopy (SEM), X-ray Diffraction analysis (XRD), and electrical measurements were performed. The response and recovery kinetics of H2 sensing are carefully described by using a two-isotherms Langmuir model, and kinetics barriers for WO3-H2 interaction are evaluated. Two microscopic processes lead to gas detection. A fast process (shorter than 4 s) is attributed to H2 interaction with adsorbed oxygen at WO3 nanorods surface. A slow process (20–1000 s), with activation energy of 0.46 eV, is attributed to oxygen vacancy generation in WO3. H intercalation in WO3 is ruled out. The recovery of WO3 after H2 exposure is also modeled. The chemo-resistive effect leading to H2 sensing by WO3 is explained through the above processes, whose kinetic barriers have been quantified. These data open the route for the development of fast, sensitive, and low-temperature operating H2 sensors based on WO3

    Fast and selective detection of volatile organic compounds using a novel pseudo spin-ladder compound CaCu2O3

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    A novel pseudo spin-ladder CaCu2O3 compound (2-leg) based conductometric gas sensor has been proposed, for the first time, for the detection of volatile organic compounds (VOCs); (a) the proposed reaction mechanism in air, and (b) in the presence of acetone and ethanol

    Congenital generalized hypertrichosis: The skin as a clue to complex malformation syndromes

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    Hypertrichosis is defined as an excessive growth in body hair beyond the normal variation compared with individuals of the same age, race and sex and affecting areas not predominantly androgen-dependent. The term hirsutism is usually referred to patients, mainly women, who show excessive hair growth with male pattern distribution. Hypertrichosis is classified according to age of onset (congenital or acquired), extent of distribution (generalized or circumscribed), site involved, and to whether the disorder is isolated or associated with other anomalies. Congenital hypertrichosis is rare and may be an isolated condition of the skin or a component feature of other disorders. Acquired hypertrichosis is more frequent and is secondary to a variety of causes including drug side effects, metabolic and endocrine disorders, cutaneous auto-inflammatory or infectious diseases, malnutrition and anorexia nervosa, and ovarian and adrenal neoplasms. In most cases, hypertrichosis is not an isolated symptom but is associated with other clinical signs including intellective delay, epilepsy or complex body malformations. A review of congenital generalized hypertrichosis is reported with particular attention given to the disorders where excessive diffuse body hair is a sign indicating the presence of complex malformation syndromes. The clinical course of a patient, previously described, with a 20-year follow-up is reported

    Treatment of central and sensorineural tinnitus with orally administered Melatonin and Sulodexide: Personal experience from a randomized controlled study

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    Since very little is understood about the exact aetiology of tinnitus, this has made treatment of the condition difficult. Even though -10-15% of the general population suffer from tinnitus, only 2% consider it serious enough to warrant any treatment. The main problem arising from tinnitus is the disturbance it causes not only in day to day life but also in sleep, leading to fatigue and general discomfort. The present study focused on the effect of Melatonin in conjunction with Sulodexide as a treatment method for tinnitus. Overall, 102 patients suffering from tinnitus were evaluated in a prospective randomised controlled study conducted in a tertiary care ENT department. After randomisation, 34 patients were treated with Melatonin and Sulodexide, another 34 were treated with Melatonin alone, while the remaining 34 (control group) were managed without treatment in order to evaluate spontaneous variations in the quality of tinnitus. Patients were assessed prospectively with the Tinnitus Handicap Inventory and Acufenometry, both pre- and post-treatment. Among the patients studied, better results with both Tinnitus Handicap Inventory and Acufenometry were found in the group who received Melatonin and Sulodexide compared to those receiving Melatonin alone. No improvement was observed in the control group. In conclusion, Melatonin in combination with Sulodexide is, in our opinion, a viable treatment option for patients suffering from central or sensorineural tinnitus

    Changes in sputum composition during 15min of sputum induction in healthy subjects and patients with asthma and chronic obstructive pulmonary disease

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    SummaryIntroductionThe use of sputum induction by inhalation of hypertonic saline to study the cellular and biochemical composition of the airways allows noninvasive sampling of the airways content and identification of markers of airways inflammation.ObjectiveThe present study aimed to identify possible changes in the cellular composition of induced sputum between samples obtained sequentially (three periods of 5min each) during one sputum induction. Moreover, difference between these samples and the mixed one (mixture of samples obtained after 5, 10 and 15min of induction) was investigated.MethodsForty-six subjects (10 healthy volunteers, 12 patients with chronic obstructive pulmonary disease (COPD) and 24 patients with asthma) (mean age 53.0±14.0yr, forced expiratory volume in one second (FEV1) 71.8±19.0% pred) produced sputum after three consecutive 5min periods of hypertonic (4.5%) saline inhalation. Stained cytospins from the three periods separately and from the mixed sample were produced and analyzed.ResultsThe mean percentage of neutrophils, eosinophils, lymphocytes and epithelial cells did not change significantly in samples obtained consecutively after 5, 10 and 15min of the induction procedure. There was no significant difference in the cellular composition of samples obtained after 5, 10 and 15min of induction and the cellular composition of the mixed sample (P=0.06).ConclusionThe separate analysis of induced sputum from three consecutive sampling and the mixed sample did not demonstrate significant changes in their cellular composition. Fifteen minutes induction procedure with the fixed concentration of hypertonic saline and processing of the mixed sample can be recommended for clinical settings and clinical trials

    Mucinous and Signet-Ring Cell Colonic Adenocarcinoma in Inflammatory Bowel Disease: A Case-Control Study

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    Simple Summary Chronic active inflammation is a known risk factor for colorectal cancer (CRC) in inflammatory bowel disease (IBD), while the adenoma-carcinoma sequence appears to be associated with sporadic CRC. In the general population, mucinous and signet-ring cell adenocarcinomas are characterized by a worse prognosis. In IBD, a higher frequency of these CRC histotypes has been reported. In the present study, we investigated the frequency and characteristics of mucinous and signet-ring cell adenocarcinomas in patients with IBD versus age-matched non-IBD Controls. CRC was more frequently represented by mucinous/signet-ring cell adenocarcinoma in IBD than in Controls. In rectal CRC, there was a higher proportion of mucinous/signet-ring cell adenocarcinoma vs. standard adenocarcinoma in IBD but not in non-IBD Controls. No risk factors for these two CRC histotypes were identified in IBD. Present findings support that the frequency of mucinous/signet-ring cell colorectal adenocarcinoma is higher in IBD, being associated with rectal involvement of CRC. A higher frequency of mucinous and signet-ring cell colonic adenocarcinoma has been reported in inflammatory bowel disease (IBD). The primary aim was to investigate the frequency of mucinous and signet-ring cell colorectal adenocarcinoma in patients with IBD (Cases) versus age-matched non-IBD Controls. The secondary aims were to compare the characteristics of these two histotypes of colorectal cancer (CRC) in IBD patients vs. Controls and to search for specific risk factors in IBD. In a case-control study, all IBD patients with CRC diagnosed from 2000 to 2022 were enrolled and matched for age (1:2) with non-IBD Controls with CRC. The study population included 120 CRC patients (40 IBD, 80 Controls). In IBD, CRC included standard adenocarcinoma in 23 (57.5%) patients mucinous/signet-ring cell adenocarcinoma in 17 (42.5%) patients. The proportion of mucinous/signet-ring cell adenocarcinoma was higher in IBD than in Controls (17 [42.5%] vs. 18 [22.5%]; p = 0.03). In rectal CRC, the proportion of mucinous/signet-ring cell adenocarcinoma was higher than standard adenocarcinoma in IBD (8 [47.1%] vs. 4 [17.4%]; p = 0.04) but not in Controls (4 [22.2%] vs. 20 [32.2%]; p = 0.59). In rectal CRC, the proportion of these two histotypes was higher in Cases than in Controls (8/12 [66.6%] vs. 4/24 [16.6%]; p = 0.008), with no risk factors identified in IBD. CRC was more frequently represented by mucinous/signet-ring cell adenocarcinoma in IBD than in age-matched non-IBD Controls. In IBD, these two CRC histotypes were more frequent in the rectum

    ZC4H2, an XLID gene, is required for the generation of a specific subset of CNS interneurons

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    Miles-Carpenter syndrome (MCS) was described in 1991 as an XLID syndrome with fingertip arches and contractures and mapped to proximal Xq. Patients had microcephaly, short stature, mild spasticity, thoracic scoliosis, hyperextendable MCP joints, rocker-bottom feet, hyperextended elbows and knees. A mutation, p.L66H, in ZC4H2, was identified in a XLID re-sequencing project. Additional screening of linked families and next generation sequencing of XLID families identified three ZC4H2 mutations: p.R18K, p.R213W and p.V75in15aa. The families shared some relevant clinical features. In silico modeling of the mutant proteins indicated all alterations would destabilize the protein. Knockout mutations in zc4h2 were created in zebrafish and homozygous mutant larvae exhibited abnormal swimming, increased twitching, defective eye movement and pectoral fin contractures. Because several of the behavioral defects were consistent with hyperactivity, we examined the underlying neuronal defects and found that sensory neurons and motoneurons appeared normal. However, we observed a striking reduction in GABAergic interneurons. Analysis of cell-type-specific markers showed a specific loss of V2 interneurons in the brain and spinal cord, likely arising from mis-specification of neural progenitors. Injected human wt ZC4H2 rescued the mutant phenotype. Mutant zebrafish injected with human p.L66H or p.R213W mRNA failed to be rescued, while the p.R18K mRNA was able to rescue the interneuron defect. Our findings clearly support ZC4H2 as a novel XLID gene with a required function in interneuron development. Loss of function of ZC4H2 thus likely results in altered connectivity of many brain and spinal circuit

    The physical scale of the far-infrared emission in the most luminous submillimetre galaxies II: evidence for merger-driven star formation

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    We present high-resolution 345 GHz interferometric observations of two extreme luminous (L_{IR}>10^{13} L_sun), submillimetre-selected galaxies (SMGs) in the COSMOS field with the Submillimeter Array (SMA). Both targets were previously detected as unresolved point-sources by the SMA in its compact configuration, also at 345 GHz. These new data, which provide a factor of ~3 improvement in resolution, allow us to measure the physical scale of the far-infrared in the submillimetre directly. The visibility functions of both targets show significant evidence for structure on 0.5-1 arcsec scales, which at z=1.5 translates into a physical scale of 5-8 kpc. Our results are consistent with the angular and physical scales of two comparably luminous objects with high-resolution SMA followup, as well as radio continuum and CO sizes. These relatively compact sizes (<5-10 kpc) argue strongly for merger-driven starbursts, rather than extended gas-rich disks, as the preferred channel for forming SMGs. For the most luminous objects, the derived sizes may also have important physical consequences; under a series of simplifying assumptions, we find that these two objects in particular are forming stars close to or at the Eddington limit for a starburst.Comment: 9 pages, 3 Figures, submitted to MNRA

    Evidence for an excess of B -> D(*) Tau Nu decays

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    Based on the full BaBar data sample, we report improved measurements of the ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or mu. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) = 0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0 sigma and 2.7 sigma, respectively. Taken together, our results disagree with these expectations at the 3.4 sigma level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model. We also report the observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.Comment: Expanded section on systematics, text corrections, improved the format of Figure 2 and included the effect of the change of the Tau polarization due to the charged Higg
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