Robust colorimetric detection based on the anti-aggregation of gold nanoparticles for bromide in rice samples

Inorganic bromide (Br⁻) is an important contaminant ion as it can originate from the overuse of illegal methyl bromide as a fumigant in stored rice samples. Herein, we developed a simple and highly sensitive colorimetric sensor for bromide ion detection in rice samples. The sensor is based on the anti-aggregation of gold nanoparticles (AuNPs) by Br⁻ in the presence of Cr³⁺, which made the method more selective than other typical aggregations of nanoparticles. The AuNPs underwent an aggregation process as a result of the coordination of Cr³⁺ and the carboxylate group of a citrate ion stabilized the AuNPs, resulting in a red-to-blue color change. When Br⁻ was pre-mixed with the AuNPs and Cr³⁺ was added, the solution color changed from blue to red with an increase in the Br⁻ concentration. The anti-aggregation process can be detected with the naked eye and monitored using UV-vis spectrophotometry. The linear calibration curve ranged between 0.31 and 3.75 μM Br⁻ with a low LOD and LOQ of 0.04 and 0.13 μM. The recovery was excellent, ranging from 79.9–92.2% with an RSD of less than 4.0%. The good inter-day and intra-day precisions were 2.9–6.4% and 3.1–7.1%, respectively. The developed sensor has proved to provide a robust method for Br⁻ detection in rice samples.

In this work, we developed a AuNP colorimetric sensor for the facile, sensitive and selective detection of bromide ions in rice samples.     

Spondyloarthropathies: using presentation to make the diagnosis

Diagnosing the spondyloarthropathies--chronic inflammatory diseases of the spine and peripheral joints that share several distinctive features--is challenging and depends on careful evaluation of the history, physical examination, and radiographs. The recent use of tumor necrosis factor inhibitors is exciting and may represent true disease-modifying drugs for these conditions.     

Serum S100β as a predictor of severity and outcomes for mixed subtype acute ischaemic stroke

INTRODUCTIONSerum S100β levels are mostly used for predicting outcomes of large-vessel stroke. Its application to mixed subtypes of acute ischaemic stroke (AIS) has been limited.METHODSPatients with mixed subtypes of AIS who were aged over 18 years and presented within 24 hours of stroke onset were consecutively enrolled. Serum S100β levels at presentation (S100β_b) and 72 hours (S100β_72hrs), and corresponding National Institutes of Health Stroke Scale (NIHSS_b and NIHSS_72hrs, respectively) scores were assessed. Stroke outcomes were evaluated using the modified Rankin Scale (mRs) at 30 days (mRs₃₀) and 90 days (mRs₉₀). Correlations between S100β_b and S100β_72hrs, as well as differences between the two (∆S100β) and the corresponding NIHSS, mRs₃₀ and mRs₉₀ scores, were evaluated (p < 0.05).RESULTS35 patients were eligible for analysis. On univariate analysis, stroke outcomes had a significant association with S100β_b, S100β_72hrs, NIHSS_b, NIHSS_72hrs and ∆S100β. Both S100β_b and S100β_72hrs correlated with corresponding NIHSS values (ρ_b = 0.51, p < 0.001; ρ_72hrs = 0.74, p < 0.001), mRs₃₀ (ρ_b = 0.58, p < 0.001; ρ_72hrs = 0.72, p < 0.001) and mRs₉₀ (ρ_b = 0.51, p = 0.002; ρ_72hrs = 0.68, p < 0.001). Correlations existed between ∆S100β and mRs₃₀ (ρ = 0.74, p < 0.001) and mRs₉₀ (ρ = 0.71, p < 0.001). Practical cut-off points for unfavourable outcomes (mRs 3–6) were S100β_72hrs > 0.288 µg/L (sensitivity 92.3%, specificity 86.4%) and ∆S100β > 0.125 µg/L (sensitivity 100%, specificity 81.8%).CONCLUSIONHigh serum S100β is associated with unfavourable outcomes for mixed subtype AIS. Cut-off values of S100β_72hrs and ∆S100β were optimal for predicting unfavourable stroke outcomes.     

Premalignant lesions of cholangiocarcinoma: characteristics on ultrasonography and MRI

Background and objective

Cholangiocarcinoma (CCA) is an aggressive malignancy with high prevalence rate in Asia. The CCA premalignant lesions, including Biliary intraepithelial neoplasia (Bil-IN) and Intraductal papillary neoplasm of biliary tract (IPNB), share a common carcinogenesis; however, on imaging, patterns of presentation are different. Patterns and imaging characteristics on ultrasonography (US) and Magnetic resonance imaging (MRI) of both Bil-IN and IPNB are reported herein.

Methods

In this retrospective study of imaging findings in premalignant CCA, pathology-proven cases of Bil-IN and IPNB at Chulabhorn Hospital were analyzed. Demographics, locations of lesions, imaging characteristics of both Bil-IN and IPNB were assessed, compared, and described.

Results

Twenty-one premalignant lesions, 13 Bil-INs and 8 IPNBs, from 18 patients were included. Both Bil-IN and IPNB lesions were found more commonly at the right than left intrahepatic ducts (66.7% vs. 33.3%), and had more peripheral than central locations (85.7% vs. 14.3%). On US, Bil-IN commonly presented as focal bile duct dilatation (76.9%), whereas IPNB was more variable with hyperechoic nodules (37.5%), focal bile duct dilatation (37.5%), and diffuse bile duct dilatation with intraductal nodules (25%). On MRI, focal bile duct dilatation and nonfunctioning bile excretion are the most sensitive findings with sensitivities in the range of 84.6% to 100%. The presence of intraductal nodules and connection to the biliary system are findings that were significantly different between IPNB and Bil-IN, 62.5% versus 7.7% (p = 0.014) and 75% versus 15.4% (p = 0.018), respectively.

Conclusions

Premalignant lesions of CCA, including Bil-IN and IPNB, have different imaging presentations. Knowledge of imaging presentations may improve early detection and increase confidence in diagnosis.