Electrochemical Biosensing Interface Based on Carbon Dots-Fe3O4 Nanomaterial for the Determination of Escherichia coli O157:H7.

Escherichia coli (E. coli) O157:H7 can cause many food safety incidents, which seriously affect human health and economic development. Therefore, the sensitive, accurate, and rapid determination of E. coli O157:H7 is of great significance for preventing the outbreak and spread of foodborne diseases. In this study, a carbon dots-Fe3O4 nanomaterial (CDs-Fe3O4)-based sensitive electrochemical biosensor for E. coli O157:H7 detection was developed. The CDs have good electrical conductivity, and the surface of carbon dots contains abundant carboxyl groups, which can be used to immobilize probe DNA. Meanwhile, the CDs can be used as a reducing agent to prepare CDs-Fe3O4 nanomaterial. The Fe3O4 nanomaterial can improve the performance of the electrochemical biosensor; it also can realize the recovery of CDs-Fe3O4 due to its magnetism. As expected, the electrochemical biosensor has excellent specificity of E. coli O157:H7 among other bacteria. The electrochemical biosensor also exhibited good performance for detecting E. coli O157:H7 with the detection range of 10-108 CFU/ml, and the detection limit of this electrochemical biosensor was 6.88 CFU/ml (3S/N). Furthermore, this electrochemical biosensor was successfully used for monitoring E. coli O157:H7 in milk and water samples, indicating that this electrochemical biosensor has good application prospect. More importantly, this research can provide a new idea for the detection of other bacteria and viruses.

[Concentrations and pollution assessment of mercury in farmland soil of Xinqiao Mining Area of Tongling, Anhui, China.] / é“œé™µæ–°æ¡¥çŸ¿åŒºå‘¨è¾¹å†œç”°åœŸå£¤æ±žå«é‡åˆ†å¸ƒç‰¹å¾åŠå ¶æ±¡æŸ“è¯„ä»·.

To investigate the effects of mining activities on mercury (Hg) enrichment in farmland soil, soil samples were collected from four villages (Xinjian Village, Yehu Village, Xinhu Village and Hucheng Village) in the vicinity of Xinqiao Mining Area, Tongling. Hg concentration was measured by atomic fluorescence spectrophotometer. The geo-accumulation index was used to evaluate the Hg pollution level of the soils. The results showed that average concentration of total Hg in farmland soil was (0.137±0.078) mg·kg-1, which exceeded the background value of soil Hg in Tongling area. The average concentration of Hg in four villages followed the order of Xinjian Village (0.221 mg·kg-1)>Xinhu Village (0.118 mg·kg-1)>Yehu Village(0.115 mg·kg-1)>Hucheng Village (0.096 mg·kg-1). Moreover, the average Hg concentration of different forms in Xinjian Village followed the order of residue (0.036 mg·kg-1) > alkali soluble (0.031 mg·kg-1) > hydrogen peroxide soluble (0.022 mg·kg-1)> acid soluble (0.020 mg·kg-1)> water soluble (0.012 mg·kg-1). The distance from the mining area was the main factor affecting the distribution of soil Hg concentration in farmlands. The contaminated Xinqiao River, to some degree, had exa-cerbated soil Hg pollution. Soil organic matter affected the accumulation and transformation of total Hg and hydrogen peroxide Hg in the farmlands. The order of the geo-accumulation index followed as Xinjian Village(1.559) >Xinhu Village(0.654) >Yehu Village(0.616) >Hucheng Village(0.356). The pollution level of farmland soil in Xinjian Village belonged to middle level of Hg pollution,which deserved more attention.

Comparison of the responsiveness of the SF-36, the Oxford Knee Score, and the Knee Society Clinical Rating System in patients undergoing total knee replacement.

OBJECTIVES: To compare the responsiveness of the Knee Society (KS) Clinical Rating System, the general health status measure Short Form 36 (SF-36), and both the raw and Rasch-based scores of the condition-specific Oxford Knee Score (OKS) in patients undergoing total knee replacement (TKR) METHODS: Data were prospectively collected as part of routine care from adult patients who underwent TKR between 2001 and 2006. OKS data fit the Rasch partial credit model after removing items regarding limping and kneeling. Responsiveness was assessed using effect size (ES), standardised response mean (SRM), and relative validity (RV). RESULTS: Among 702 patients with complete data at baseline and two follow-ups, the pain subscale of the KS (KS-P), raw-OKS, and Rasch-OKS consistently had higher levels of responsiveness than all eight SF-36 and the other KS subscales. At 6-month follow-up, Rasch-OKS had the largest ES and KS-P had the largest SRM (2.7 and 2.0, respectively). When compared to raw-OKS, the RVs of KS-P, Rasch-OKS, SF-36 bodily pain, and SF-36 physical functioning were 1.1, 0.66, 0.49, and 0.36, respectively. A similar ordering of responsiveness was observed at 24-month follow-up. CONCLUSION: The OKS and KS-P are more responsive than most SF-36 subscales in TKR patients. Raw-OKS and Rasch-OKS have comparable responsiveness. Different responsiveness indices may give different results.

Natural occurrence of ochratoxin A in wolfberry fruit wine marketed in China.

Wolfberry fruit wine (WFW) is widely used as a global functional food to improve the immune system and prevent human disease. A total of 36 bottled WFWs were randomly collected in China between 2005 and 2010. Samples were analysed for the presence of ochratoxin A (OTA) using immunoaffinity column (IAC) clean-up and high-performance liquid chromatography with fluorescence detection (HPLC-FLD). Positive results were confirmed by liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS). The limit of detection (LOD), based on a signal-to-noise ratio of 3, was 0.05 ng mL⁻¹. Recoveries ranged from 78.3% to 94.7% and relative standard deviations from 1.1% to 4.3% within the spiking range of 0.2-20 ng mL⁻¹. OTA was detected in one sample, below the maximum allowable limit as established by the European community.

A study on indirect and intangible costs for patients with knee osteoarthritis in Singapore.

OBJECTIVES: To estimate indirect costs through human capital approach and intangible costs through willingness-to-pay (WTP), and identify factors potentially affecting these costs in multiethnic Asian patients with knee osteoarthritis (OA). METHODS: Data were collected through face-to-face interviews among knee OA patients. Human capital approach was used to estimate indirect costs by multiplying: 1) days of absence from work because of OA, with average earnings per capita per day for working patients; or 2) productivity loss with the market price of housekeeping for retirees/homemakers. A closed-ended iterative bidding contingent valuation method was used to elicit willingness-to-pay for a hypothetical cure of OA as a proxy for intangible costs. Mann-Whitney U or Kruskal-Wallis H-tests were performed in univariate analyzes, and linear regression in multivariate analyses. RESULTS: Indirect costs per year and intangible costs were estimated at US$1008 and US$1200, accounting for 2.8% and 3.3% of annual household income, respectively. The indirect costs were significantly higher for male or working patients, while intangible costs were higher for Chinese, working patients, with higher income, or worse global well-being. CONCLUSION: This study demonstrated that eliciting indirect costs through human capital approach and intangible costs through WTP are acceptable and feasible in Asian patients with knee OA. Besides the direct costs, the indirect and intangible costs for the OA patients could be substantial.

Comparison of the EuroQol and short form 6D in Singapore multiethnic Asian knee osteoarthritis patients scheduled for total knee replacement.

OBJECTIVE: To compare the EuroQol (EQ-5D) and Short Form 6D (SF-6D) among multiethnic Asian patients with knee osteoarthritis (OA) scheduled for total knee replacement in Singapore. METHODS: Patients were asked to complete questionnaires including the EQ-5D, Short Form 36, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Lequesne knee index. EQ-5D and SF-6D utility scores were calculated using the scoring algorithms developed from the UK general population. Agreement between the 2 instruments was assessed by comparing their score distributions, means, medians, intraclass correlation coefficients (ICCs), and a Bland-Altman plot. Correlations of the EQ-5D and SF-6D with WOMAC and Lequesne knee index scores were also examined. RESULTS: A consecutive sample of 258 knee OA patients (127 English-speaking and 131 Chinese-speaking) participated. The mean +/- SD EQ-5D utility score was 0.49 +/- 0.31 (range -0.25-1.00) and the mean SF-6D utility score was 0.63 +/- 0.12 (range 0.32-0.89). In a hypothetical example, this 0.14-point difference in mean utility scores yielded a difference of $10,000/quality-adjusted life year (QALY) in cost-effectiveness ratios. The score distribution was bimodal for the EQ-5D and normal for the SF-6D. This poor agreement was also demonstrated by the Bland-Altman plot and the low ICC (range 0.18-0.54). Correlations of the WOMAC and Lequesne index with the EQ-5D were higher than with the SF-6D. CONCLUSION: Using different preference-based health-related quality of life instruments may yield different utility scores, which could have a great impact on QALY estimates. This highlights the importance of selecting appropriate instruments for economic evaluation. Additional research is needed to determine which instrument (the EQ-5D or the SF-6D) should be used in OA patients.

Direct and indirect costs of osteoarthritis in Singapore: a comparative study among multiethnic Asian patients with osteoarthritis.

OBJECTIVE: To estimate and compare the direct and indirect costs of osteoarthritis (OA) in multiethnic Asian patients with OA in Singapore. METHODS: The study was a retrospective and cross-sectional design. Patients were stratified according to ethnicity and presence or absence of joint surgery. Direct costs were estimated from both a societal and a patient perspective using the Singapore General Hospital database; indirect costs were estimated using the human capital approach. All costs were expressed as mean costs per patient per annum in 2003 Singapore dollars. RESULTS: A total of 1179 patients (83.6% Chinese, 7.2% Malay, 3.5% Indian, 5.7% others) were included in estimating direct costs, of which 513 (43.5%) had total knee replacement (TKR) and 92 (7.8%) total hip replacement (THR), while 105 patients (71.4% Chinese, 14.3% Malay, 14.3% Indian) were included in estimating indirect costs. Direct costs to patients ranged from 1460 dollars to 7477 dollars for Chinese, 1362 dollars-7211 dollars for Malays, 1688 dollars-6226 dollars for Indians, and 1437 dollars-12,140 dollars for other ethnic patients; direct costs to society ranged from 3351 dollars to 15,799 dollars for Chinese, 2939 dollars-15,436 dollars for Malays, 3150 dollars-10,990 dollars for Indians, and 2597 dollars-17,879 dollars for other ethnic patients. In contrast, the indirect costs ranged from 1215 dollars to 3834 dollars for Chinese, 1138 dollars-6116 dollars for Malays, and 1371 dollars-5292 dollars for Indians. However, most ethnic variations were not statistically significant. CONCLUSION: The economic burden of OA to society and patients increased by 3-fold or more in the patients with TKR/THR compared to those without. The ethnic differences in health resources consumed were more apparent when the disease progressed.