Blood coagulation dynamic testing sensor based on electromagnetic vibration.

Rapid detection techniques and methods of blood coagulation have attracted wide attention in academia and the business community in the presence of the increased demands for rapid assessment (point-of-care testing) of patients from surgery, intensive care unit, and other departments. The differential equation of vibration system composed of elastic support and electromagnetic induction devices was set up using the principle of damping vibration and establishing the dynamics model; meanwhile, the harmonic response analysis and vibration fatigue coupling analysis were carried out, the analysis results were optimized, and the experimental device of the electromagnetic induction testing sensor was established. In addition, the experimental device with blood coagulation reagent was assorted to establish the standard point-of-care testing rapid blood coagulation detection curve, and to compare the testing curve with that of the imported point-of-care testing blood coagulation instrument. The results showed that the first-order natural frequency of the designed sensor was 102.35 Hz, the correlation between the designed sensor and the imported equipment was 0.996, and the testing repeatability of the designed sensor could reach 0.002. Therefore, the designed blood coagulation testing sensor based on electromagnetic induction had the characteristics of favorable elasticity and anti-fatigue, which could meet the accuracy requirements of clinical detection. Taken together, this study could provide the core technology for developing the point-of-care testing instrument for blood coagulation dynamic testing.

Phosphorescent quantum dots/ethidium bromide nanohybrids based on photoinduced electron transfer for DNA detection.

Mercaptopropionic acid-capped Mn-doped ZnS quantum dots/ethidium bromide (EB) nanohybrids were constructed for photoinduced electron transfer (PIET) and then used as a room-temperature phosphorescence (RTP) probe for DNA detection. EB could quench the RTP of Mn-doped ZnS QDs by PIET, thereby forming Mn-doped ZnS QDs/EB nanohybrids and storing RTP. Meanwhile, EB could be inserted into DNA and EB could be competitively desorbed from the surface of Mn-doped ZnS QDs by DNA, thereby releasing the RTP of Mn-doped ZnS QDs. Based on this mechanism, a RTP sensor for DNA detection was developed. Under optimal conditions, the detection limit for DNA was 0.045 mg L(-1), the relative standard deviation was 1.7%, and the method linear ranged from 0.2 to 20 mg L(-1). The proposed method was applied to biological fluids, in which satisfactory results were obtained.

Toxicity of sodium fluoride to Caenorhabditis elegans.

OBJECTIVE: To investigate the toxic effect of sodium fluoride (NaF) on the nematode Caenorhabditis elegans (C. elegans). METHODS: Adult C. elegans were exposed to different concentrations of NaF (0.038 mmol/L, 0.38 mmol/L, and 3.8 mmol/L) for 24 h. To assess the physiological effects of NaF, the brood size, life span, head thrashes, and body bend frequency were examined. Reactive oxygen species (ROS) and cell apoptosis were detected as parameters of biochemical response. The gene expressions were determined by real-time polymerase chain reaction (PCR) to assess the molecular-level response. RESULTS: At the physiological level, the brood size of C. elegans exposed to 0.038 mmol/L, 0.38 mmol/L, and 3.8 mmol/L concentrations of NaF were reduced by 6%, 26%, and 28% respectively in comparison with the control group. The maximum life spans of C. elegans exposed to 0.038 mmol/L, 0.38 mmol/L, and 3.8 mmol/L concentrations of NaF were reduced by 3 days and 5 days, respectively. Head thrashes and body bend frequency both decreased with increasing concentrations of NaF. At the biochemical level, the production of ROS and the incidence of cell apoptosis increased with increasing concentrations of NaF (P < 0.05). At the molecular level, different concentrations of NaF exposure raised the expression of stress-related genes, such as hsp16.1, sod-3, ctl-2, dhs-28, gst-1, and cep-1. CONCLUSION: NaF exposure could induce multiple biological toxicities to C. elegans in a concentration-dependent manner. These toxicities may be relevant to the oxidative stress induced by increased ROS production and accumulation in C. elegans.

Point prevalence surveys of healthcare-associated infection in 13 hospitals in Hubei Province, China, 2007-2008.

Successive point prevalence surveys were conducted in November 2007 and 2008 to monitor the prevalence of healthcare-associated infection (HCAI) in 13 grade III, 1st class hospitals in Hubei Province of China, using the case definition criteria established by the Ministry of Health in the People's Republic of China. In total, of 20 350 patients surveyed, 833 (4.09%) HCAIs were observed in 790 (3.88%) patients. There was no significant difference between the overall prevalence of HCAI in 2007 (4.14%) and 2008 (3.72%). Respiratory tract infection was the most common HCAI (63.15%), followed by surgical site infection (9.60%) and urinary tract infection (8.64%). Only 35.29% (294/833) of HCAI patients had positive microbiology results. Gram-negative bacteria were isolated most frequently and the most frequent organism was Pseudomonas aeruginosa, followed by Escherichia coli, Acinetobacter baumannii and Staphylococcus aureus. Antibiotic use was documented for 10,344 (50.83%) patients, and cephalosporins, penicillins, and quinolones were the most commonly used agents for treatment or prophylaxis.