Objective To investigate the situation of food contamination by lead,cadmium,mercury,copper and aluminum in Ningxia Region.Methods Ten categories of food samples up to 712 copies including dairy,edible mushrooms,eggs,preserved egg,meat,organs,aquatic products,vegetables,grains and pasta from supermarkets of five administrative cities of Ningxia Autonomous Region were selected in 2010.The contents of lead,cadmium and mercury in food were detected in 646 samples of 9 categories of food,and copper content of the 30 meat samples were detected.Aluminum content in 66 samples of flour food was tested.According to the methods of national food safety standards (GB 5009.12-2010) and national food hygiene standards (GB/T 5009.13-2003,GB/ T 5009.15-2003 and GB/T 5009.17-2003),lead,copper,cadmium and mercury in various foods were tested.Aluminum was determined using the method for determination of spectrophotometry.Results The detection rates of lead,cadmium,mercury in the nine categories of food were 52.8％ (341/646),62.1％ (401/646),51.7％ (334/646);the detection rates of copper in the meat was 90.0％ (27/30);the aluminum in flour food was 84.8％ (56/66),respectively.Compared with the national standards,the eligible rates of lead,cadmium,mercury,copper and aluminum were 97.1％ (627/646),98.2％ (539/549),100.0％ (646/646),100.0％ (30/30) and 75.8％ (50/66),respectively.Food contaminated by lead and cadmium were mainly distributed in preserved egg [lead detection rate 9.5％ (2/21)],organs [lead detection rate 6.7％ (2/30),cadmium detection rate 30.0％ (9/30)],vegetables [lead detection rate 9.9％ (8/90)] and a small amount of food products [lead detection rate 4.7％ (7/150)].The levels of lead in fried flour food and fine dried noodles were higher [40.9％ (9/22),36.4％ (4/11)].Conclusions Food contamination by lead,cadmium,mercury and copper is not serious in Ningxia.The monitoring results of lead,cadmium,mercury and copper in food are satisfying in Ningxia.But there is aluminum contamination in flour food.It is important to do the risk evaluation of aluminum contamination in food as quickly as possible.

OBJECTIVETo investigate the method for uncertainty evaluation of determination of tin and its compounds in the air of workplace by flame atomic absorption spectrometry.

METHODSThe national occupational health standards, GBZ/T160.28-2004 and JJF1059-1999, were used to build a mathematical model of determination of tin and its compounds in the air of workplace and to calculate the components of uncertainty.

RESULTSIn determination of tin and its compounds in the air of workplace using flame atomic absorption spectrometry, the uncertainty for the concentration of the standard solution, atomic absorption spectrophotometer, sample digestion, parallel determination, least square fitting of the calibration curve, and sample collection was 0.436%, 0.13%, 1.07%, 1.65%, 3.05%, and 2.89%, respectively. The combined uncertainty was 9.3%.The concentration of tin in the test sample was 0.132 mg/m³, and the expanded uncertainty for the measurement was 0.012 mg/m³ (K=2).

CONCLUSIONThe dominant uncertainty for determination of tin and its compounds in the air of workplace comes from least squares fitting of the calibration curve and sample collection. Quality control should be improved in the process of calibration curve fitting and sample collection.

Air Pollutants, Occupational ; analysis ; Models, Theoretical ; Spectrophotometry, Atomic ; Tin ; analysis ; Uncertainty ; Workplace

Objective To study the value of postmortem imaging on the diagnosis of intestinal perforation.Method Postmortem imaging(PMCT and PMCTA)data of 2 intestinal perforation deaths(and 4 controlled cases)were reviewed retrospectively.Diagnosing capacities of intestinal perforation by postmortem imaging method were further investigated.Results PMCT is sensitive in detecting the free air and liquid induced by intestinal perforation.PMCT can sometimes detect the gravity-dependent purulent secretions in the abdominopelvic cavity.PMCTA can visualize the extravasation of contrast agent from the perforation,which can be used to locate the accurate perforation region.Conclusion Postmortem imaging method(PMCT and PMCTA)is an important tool for the diagnosis of intestinal perforation,which can not only be used as a forensic diagnosis method,but is also useful to locate the perforation site before an forensic autopsy.

Medulloblastoma (MB) is a common yet highly heterogeneous childhood malignant brain tumor, however, clinically effective molecular targeted therapy is lacking. Modulation of hedgehog (HH) signaling by epigenetically targeting the transcriptional factors GLI through bromodomain-containing protein 4 (BRD4) has recently spurred new interest as potential treatment of HH-driven MB. Through screening of current clinical BRD4 inhibitors for their inhibitory potency against glioma-associated oncogene homolog (GLI) protein, the BRD4 inhibitor