Immunofluorescent-aggregation assay based on anti-Salmonella typhimurium IgG-AuNCs, for rapid detection of Salmonella typhimurium.

Sensitive and rapid detection of pathogenic bacteria plays an important role in avoiding food poisoning. However, the practical application value of conventional assays for detection of foodborne bacteria, are limited by major drawbacks; these include the laboriousness of pure culture preparation, complexity of DNA extraction for polymerase chain reaction, and low sensitivity of enzyme-linked immunosorbent assay. Herein, we designed a non-complex strategy for the sensitive, quantitative, and rapid detection of Salmonella typhimurium with high specificity, using an anti-Salmonella typhimurium IgG-AuNC-based immunofluorescent-aggregation assay. Salmonella typhimurium was agglutinated with fluorescent anti-Salmonella typhimurium IgG-AuNC on a glass slide, and observed using a fluorescence microscope with photoexcitation and photoemission at 560 nm and 620 nm, respectively. Under optimized reaction conditions, the AuNC-based immunofluorescent-aggregation assay had a determination range between 7.0 × 103 and 3.0 × 108 CFU/mL, a limit of detection of 1.0 × 103 CFU/mL and an assay response time of 3 min. The technique delivered good results in assessing real samples.

Exploring Public Awareness of Overwork Prevention With Big Data From Google Trends: Retrospective Analysis.

BACKGROUND: To improve working conditions and prevent illness and deaths related to overwork, the Taiwanese government in 2015, 2016, and 2018 amended regulations regarding working time, overtime, shifts, and rest days. Such policy changes may lead to a rising public awareness of overwork-related issues, which may in turn reinforce policy development. OBJECTIVE: This study aimed to investigate to what extent public awareness of overwork-related issues correlated with policy changes. METHODS: Policies, laws, and regulations promulgated or amended in Taiwan between January 2004 and November 2019 were identified. We defined 3 working conditions (overwork, long working hours, and high job stress) related to overwork prevention, generated a keyword for each condition, and extracted the search volumes for each keyword on the Google search engine as proxy indicators of public awareness. We then calculated the monthly percentage change in the search volumes using the Joinpoint Regression Program. RESULTS: Apparent peaks in search volumes were observed immediately after policy changes. Especially, policy changes in 2010 were followed by a remarkable peak in search volumes for both overwork and working hours, with the search volumes for overwork increased by 29% per month from June 2010 to March 2011. This increase was preceded by the implementation of new overwork recognition guidelines and media reports of several suspected overwork-related events. The search volumes for working hours also steadily increased, by 2% per month in September 2013 and afterward, reaching a peak in January 2017. The peak was likely due to the amendment to the Labor Standards Act, which called for "1 fixed and 1 flexible day off per week," in 2016. The search volumes for job stress significantly increased (P=.026) but only by 0.4% per month since March 2013. CONCLUSIONS: Over the past 15 years, Taiwanese authorities have revised and implemented several policies to prevent overwork-related health problems. Our study suggests a relationship between the implementation of policies that clearly defined the criteria for overwork and working hours and the rising public awareness of the importance of overwork prevention and shorter working hours.

[Analysis of Gene Mutation Types of Thalassemia in Quanzhou Area of Fujian Province in China].

OBJECTIVE: To investigate the gene mutation types and gene carrying rate of common thalassemia in patients with thalassemia in Quanzhou, and to analyze its molecular epidemiological characteristics in Quanzhou. METHODS: 546 patients with thalassemia diagnosed at the first hospital of Quanzhou from January 2017 to October 2018 were collected and retrospectively analyzed for their types of mutations and carrier rates. RESULTS: Among the 4226 samples submitted, 546 positive samples were detected, the total carrying rate of the thalassaemia genes was 12.92%; the carrier rate of α-thalassemia was 8.16%; the carrier rate of ß-thalassemia was 4.76%; There were more α-thalassemia missing patients than non-deleted patients. The Southeast Asian deletion type (--SEA /αα) was the most common one, with a composition ratio of 68.98%, which was followed by 22.61% (-α3.7/αα), 2.61% (αWSα/αα), and 2.32% (ααCS/αα), 2.32% (αQSα/αα), 1.16% (-α4.2/αα); 9 types of ß-thalassemia gene mutations were detected. The most common three mutations were IVSII-654 (C→T, 42.29%), CD41-42 (-TTCT, 33.83%), CD17 (A→T, 12.94%). 2 cases of --THAI/αα , 1 case of αα/αααanti3.7 and 1 case of HKαα were detected. CONCLUSION: This study shows that the gene carrying rate of thalassemia in Quanzhou is high and has diversity, which can provide some reference for the prevention and control of thalassemia in Quanzhou.

[Epidemiological Survey of Thalassemia in Women of childbearing age in Quanzhou Area of Fujian Province in China].

OBJECTIVE: To investigate the gene prevalence and spectrum of thalassemia in the women of childbearing age in quanzhou area. METHODS: Venous blood of the women were collected for study, all subjects were registered in each county of quanzhou area by using cluster sampling. Both the mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) were used for screening thalassemia．Genotyping of the screened positive samples was performed by gap single polymerase chain reaction (gap-PCR) and reverse dot blot (RDB) hybridization．Unknown positive samples were analyzed with DNA sequencing. RESULTS: Out of all 7 082 samples, Three hundred and eighty four were identified as thalassemia gene carriers with a carrying rate of 5.42 %. The α and ß thalassemia were 3.21% and 2.15% respectively. --SEA /αα was the most common genotype with 68.72 % in mutation types of α thalassemia, In addition gene, 2 cases of --THAI/αα and 1 case of αα/αααanti3.7 were also detected. IVS-Ⅱ-654/N and CD41-42/N were the most common gentypes with 75.00 % in mutation types of ß thalassemia gene, 5 cases were found to be α ß compogite thalassemia. CONCLUSION: The carrying rate of thalassemia gene in quanzhou area is higher, and with the most common gentypes including --SEA /αα、IVSⅡ-654(C→T)/N and CD41-42(-TTCT)/N. The study results are beneficial for the screening of thalassemia in the genetic consultation and the prenatal gene diagnosis.

Peroxidase-like activity of nanocrystalline cobalt selenide and its application for uric acid detection.

Dendrite-like cobalt selenide nanostructures were synthesized from cobalt and selenium powder precursors by a solvothermal method in anhydrous ethylenediamine. The as-prepared nanocrystalline cobalt selenide was found to possess peroxidase-like activity that could catalyze the reaction of peroxidase substrates in the presence of H2O2. A spectrophotometric method for uric acid (UA) determination was developed based on the nanocrystalline cobalt selenide-catalyzed coupling reaction between N-ethyl-N-(3-sulfopropyl)-3-methylaniline sodium salt and 4-aminoantipyrine (4-AAP) in the presence of H2O2. Under optimum conditions, the absorbance was proportional to the concentration of UA over the range of 2.0-40 µM with a detection limit of 0.5 µM. The applicability of the proposed method has been validated by determination of UA in human serum samples with satisfactory results.