Electrocatalytic performance of tyrosinase detection in Penaeus vannamei based on a [(PSS/PPy)(P2Mo18/PPy)5] multilayer composite film modified electrode.

Polyoxometalates (POMs) are widely used in the preparation of sensors that detect the content of substances because of their excellent electron transfer capabilities. In this paper, a [(PSS/PPy)(P2Mo18/PPy)5] multilayer composite film modified electrode was prepared by the potentiostatic deposition method. The electrochemical performance of the modified electrode was studied by cyclic voltammetry under the conditions of different modified layers, different supporting electrolytes and different sweep rates. Different concentrations of tyrosinase were catalyzed by the modified electrode under a suitable supporting electrolyte, and the electrochemical sensing of tyrosinase by the modified electrode was studied. The research results show that the modified electrode has good stability and reproducibility for electrochemical sensing of tyrosinase, and the response current has a good linear relationship with the amount of tyrosinase added. Taking peak III as an example, the detection limit (S/N = 3) was 2.7649 U mL-1. It can be known from the timing ampere curve that as the concentration of tyrosinase in the reaction system continues to increase, its response current increases stepwise, providing a linear curve in the range of 3.66 U mL-1 to 26.87 U mL-1, and the minimum detection limit (S/N = 3) reaches 0.0021 U mL-1. The [(PSS/PPy)(P2Mo18/PPy)5] multilayer composite membrane modified electrode was used to detect tyrosinase in Penaeus vannamei. The spiked recovery of the sample was 96.3-100.8%, indicating that the modified electrode has high accuracy and can be used for the detection of tyrosinase in actual samples.

A stepwise approach in the management of chronic spontaneous urticaria in children.

BACKGROUND: There is limited literature in the management of chronic urticaria in children. Treatment algorithms are generally extrapolated from adult studies. OBJECTIVE: Utility of a weight and age-based algorithm for antihistamines in management of chronic spontaneous urticaria (CSU) in childhood. To document associated factors that predict for step of control of CSU and time taken to attain control of symptoms in children. METHODS: A workgroup comprising of allergists, nurses, and pharmacists convened to develop a stepwise treatment algorithm in management of children with CSU. Sequential patients presenting to the paediatric allergy service with CSU were included in this observational, prospective study. RESULTS: Ninety-eight patients were recruited from September 2012 to September 2013. Majority were male, Chinese with median age 4 years 7 months. A third of patients with CSU had a family history of acute urticaria. Ten point two percent had previously resolved CSU, 25.5% had associated angioedema, and 53.1% had a history of atopy. A total of 96.9% of patients achieved control of symptoms, of which 91.8% achieved control with cetirizine. Fifty percent of all the patients were controlled on step 2 or higher. Forty-seven point eight percent of those on step 2 or higher were between 2 to 6 years of age compared to 32.6% and 19.6% who were 6 years and older and lesser than 2 years of age respectively. Eighty percent of those with previously resolved CSU required an increase to step 2 and above to achieve chronic urticaria control. CONCLUSION: We propose a weight- and age-based titration algorithm for different antihistamines for CSU in children using a stepwise approach to achieve control. This algorithm may improve the management and safety profile for paediatric CSU patients and allow for review in a more systematic manner for physicians dealing with CSU in children.

[Biomechanical analysis on healing process of sagittal fracture of the mandibular condyle after rigid fixation].

PURPOSE: To analyze the biomechanical healing process on rigid fixation of sagittal fracture of the mandibular condyle (SFMC), and to provide guidelines for surgical treatment. METHODS: Three-dimensional finite element model (3D-FEAM) of mandible and condyle was established. The right condyle was simulated as SFMC with 0.1 mm space across the condyle length ways. The 3D-FEAM of rigid fixation was established. The biomechanical factors such as stress distribution of condylar surface, displacement around fracture, stress on the plate and stress shielding were calculated during 0, 4, 8 and 12-week after rigid fixation. RESULTS: The maximum equivalent stress of normal condyle was located at the area of middle 1/3 of condylar neck. The maximum equivalent stress at 0-week after fixation was 23 times than that on normal condyle. They were located at the condylar stump and the plate near inferior punctual areas of fracture line. There were little stress on the other areas. The maximum equivalent stress at 4, 8 and 12-week was approximately 6 times than that on normal condyle. They were located at the areas same as the area at 0-week. There were little stress on the other areas at the condyle. The maximum total displacement and maximum total corner were increased 0.57-0.75 mm and 0.01-0.09° respectively during healing process. The maximum equivalent stress at 0-week on the condylar trump was 5-6 times compared with that at 4, 8, and 12-week. The maximum equivalent stress, maximum total displacement and maximum total corner on the fractured fragment were not changed significantly during healing process. The maximum equivalent stress at 0-week on the plate was 7-9 times compared with that at 4, 8, 12-week. CONCLUSIONS: The stress of the condyle and stress shielding of the plate may be the reasons of absorbing and rebuilding on the condyle in healing process of SFMC. The biomechanical parameters increase obviously at 4-week after fixation. Elastic intermaxillary traction is necessary to decrease total displacement and total corner of the condyle, and liquid diet is necessary to decrease equivalent stress within 4 weeks. Rehabilitation training should be used to recover TMJ functions after 4 weeks because the condyle and mandible have the ability to carry out normal functions.

[Effects of delayed opening of infarct-related artery on late left ventricular remodeling in patients with acute anterior myocardial infarction].

OBJECTIVE: To assess the effect of delayed opening of the infarct-related artery (IRA) by percutaneous coronary intervention (PCI) on the late left ventricular remodeling after acute anterior myocardial infarction (AAMI). METHODS: Sixty four patients with initial Q-wave AAMI and with the total occluded IRA conformed by angiogram at 9.1 +/- 2.3 (2 - 14) days after the onset were divided into successful PCI group and control group (not receiving PCI or the IRA not re-opened). Two-D echocardiogram was performed at acute phase (about 3 weeks), 2 and 6 months after onset of AAMI respectively to detect the left ventricular function and left ventricular wall motion abnormality (VWMA). The total congestive heart failure events were recorded during 6 months follow-up. RESULTS: VWMA scores, left ventricular ejection fraction (LVEF), left ventricular end-diastolic and end-systolic volume indexes (LVEDVI and LVESVI) were similar in 2 groups at acute phase and 2 months after the onset of AAMI. There were no differences between the parameters above at acute phase and 2 months in each group too. VWMA scores and LVEF did not changed significantly at 6 months in each group compared with those at acute phase and 2 months (P > 0.05). But LVEDVI and LVESVI were significantly smaller in the successful PCI group than those in the control group (P < 0.01, P < 0.05). The rate of congestive heart failure events was 19% in control group and 2.0% in successful PCI group (P > 0.05) respectively. CONCLUSIONS: Delayed opening of IRA in AAMI could prevent the late phase but not the early phase of left ventricular remodeling after AMI.