Positive Contrast Imaging of SPIO Nanoparticles

It is advantageous to achieve positive contrast images instead of negative contrast images in superparamagnetic iron-oxide (SPIO) nanoparticles-based MR imaging in order to distinguish the signal surrounding SPIO nanoparticles from the dark signal due to local field inhomogeneity and the artifacts due to tissue interface and background noise, eliminate the inherent defects in the traditional MRI such as partial-volume effects and large void volume for reliable visualization, and increase contrast-to-noise ratio. Many methods generating positive signal with SPIO nanoparticles have been developed in the last decade. This paper provides an overview of current visualization methods and states their advantages and disadvantages. In practice, these techniques have been widely applied to cell labeling and disease diagnosis and monitoring. However, there is still a need for an ideal method to achieve both accuracy and sensitivity

Metabolic responses of HeLa cells to silica nanoparticles by NMR-based metabolomic analyses

Silica nanoparticles are increasingly used in the biomedical fields due to their excellent solubility, high stability and favorable biocompatibility. However, despite being considered of low genotoxicity, their bio-related adverse effects have attracted particular concern from both the scientific field and the public. In this study, human cervical adenocarcinoma cells (HeLa line) were exposed to 0.01 or 1.0 mg/mL of hydrophilic silica nanoparticles. The H-1 NMR spectroscopy coupled with multivariate statistical analysis were used to characterize the metabolic variations of intracellular metabolites and the compositional changes of the corresponding culture media. At the early stage of silica nanoparticles-exposure, no obvious dose-effect of HeLa cell metabolome was observed, which implied that cellular stress-response regulated the metabolic variations of HeLa cell. Silica nanoparticles induced the increases of lipids including triglyceride, LDL, VLDL and lactate/alanine ratio and the decreases of alanine, ATP, choline, creatine, glycine, glycerol, isoleucine, leucine, phenylalanine, tyrosine, and valine, which involved in membrane modification, catabolism of carbohydrate and protein, and stress-response. Subsequently, a complicated synergistic effect of stress-response and toxicological-effect dominated the biochemical process and metabolic response, which was demonstrated in the reverse changes of some metabolites including acetate, ADP, ATP, choline, creatine, glutamine, glycine, lysine, methionine, phenylalanine and valine between 6 and 48 h post-treatment of silica nanoparticles. The toxicological-effects induced by high-dosage silica nanoparticles could be derived from the elevated levels of ATP and ADP, the utilization of glucose and amino acids and the production of metabolic end-products such as glutamate, glycine, lysine, methionine, phenylalanine, and valine. The results indicated that it is important and necessary to pursue further the physiological responses of silica nanoparticles in animal models and human before their practical use. NMR-based metabolomic analysis helps to understand the biological mechanisms of silica nanoparticles and their metabolic fate, and further, it offers an ideal platform for establishing the bio-safety of existing and new nanomaterials.Silica nanoparticles are increasingly used in the biomedical fields due to their excellent solubility, high stability and favorable biocompatibility. However, despite being considered of low genotoxicity, their bio-related adverse effects have attracted particular concern from both the scientific field and the public. In this study, human cervical adenocarcinoma cells (HeLa line) were exposed to 0.01 or 1.0 mg/mL of hydrophilic silica nanoparticles. The H-1 NMR spectroscopy coupled with multivariate statistical analysis were used to characterize the metabolic variations of intracellular metabolites and the compositional changes of the corresponding culture media. At the early stage of silica nanoparticles-exposure, no obvious dose-effect of HeLa cell metabolome was observed, which implied that cellular stress-response regulated the metabolic variations of HeLa cell. Silica nanoparticles induced the increases of lipids including triglyceride, LDL, VLDL and lactate/alanine ratio and the decreases of alanine, ATP, choline, creatine, glycine, glycerol, isoleucine, leucine, phenylalanine, tyrosine, and valine, which involved in membrane modification, catabolism of carbohydrate and protein, and stress-response. Subsequently, a complicated synergistic effect of stress-response and toxicological-effect dominated the biochemical process and metabolic response, which was demonstrated in the reverse changes of some metabolites including acetate, ADP, ATP, choline, creatine, glutamine, glycine, lysine, methionine, phenylalanine and valine between 6 and 48 h post-treatment of silica nanoparticles. The toxicological-effects induced by high-dosage silica nanoparticles could be derived from the elevated levels of ATP and ADP, the utilization of glucose and amino acids and the production of metabolic end-products such as glutamate, glycine, lysine, methionine, phenylalanine, and valine. The results indicated that it is important and necessary to pursue further the physiological responses of silica nanoparticles in animal models and human before their practical use. NMR-based metabolomic analysis helps to understand the biological mechanisms of silica nanoparticles and their metabolic fate, and further, it offers an ideal platform for establishing the bio-safety of existing and new nanomaterials

Incidence of biliary atresia associated congenital malformations: A retrospective multicenter study in China

SummaryBackgroundSome patients with biliary atresia (BA) have associated anomalies. Our study aimed to investigate the incidence of BA-associated malformations in mainland China, and compare the results with those reported in the Western literature.MethodsClinical data were collected retrospectively from five medical centers in mainland China. BA patients were diagnosed and confirmed by laparotomy with intraoperative cholangiography and liver biopsy. Cases were divided into isolated type BA and BA with associated anomalies, including polysplenia, situs inversus, intestinal malrotation, and cardiovascular anomalies.ResultsA total of 851 BA patients were recruited from Tianjin, Beijing, Wuhan, Guangzhou, and Shenzhen. Patients were grouped as follows: Type I, 13 cases (1.5%); Type II, five cases (0.6%); Type III, 833 cases (97.9%). Forty-two (4.94%) patients had 54 associated congenital abnormalities. The intra-abdominal anomalies included polysplenia (n = 4, 1 fusion between liver and spleen), situs inversus (n = 2), and intestinal malrotation (n = 3). The cardiovascular anomalies included atrial septal defect and ventricular septal defect (n = 29), patent foramen ovale (n = 1), patent ductus arteriosus (n = 4), and other cardiac malformations (n = 3, including coronary sinus dilation, left superior vena cava, Tetralogy of Fallot).ConclusionOur data showed that spleen anomaly is not as common as reported in the Western literature. The difference may suggests different genetic and environmental risk factors for BA

An expert system based on 1 H NMR spectroscopy for quality evaluation and adulteration identification of edible oils

Abstract(#br)The advantages of nuclear magnetic resonance (NMR) such as nondestructive and simultaneous detection, high reproducibility and rapidity make it easily develop the objective and credible methods for food analysis and identification. In this study, we developed a computer-aided, MATLAB-scripted expert system which enables NMR data to distinguish different edible oils and evaluate the quality of edible oils. The NMR spectral data of seven species of most popular vegetable edible oils in China were used to establish the assessment criterions including the content percentage of fatty acids and the quality parameters of edible oils. In our case, the identification accuracy of vegetable origin for the pure edible oils is 95.83% and that for the mixed edible oils is 89.58%, and all the recycled waste cooking oils and fried oils were correctly screened out and identified by the expert system. Further, the quality information of the edible oils was also provided. Our results show that the current expert system is a fast, easy-operated and convenient tool for the adulteration identification and quality control of edible oils

Improved position offset based parameter determination of permanent magnet synchronous machines under different load conditions

© The Institution of Engineering and Technology 2017.This study proposes a novel method for the parameter determination of permanent magnet (PM) synchronous machines under different load conditions. It can identify the total dq-axis flux linkages and also the PM flux linkage separately by the addition of a pair of negative and positive position offsets. It is also noteworthy that the influence of uncertain inverter non-linearity and winding resistance is cancelled during the modelling process, and the experimental results on two different PM synchronous machines show a good agreement with the finite-element prediction results. More importantly, it shows good performance in online tracking the variation of PM flux linkage, which is an important feature for aiding the condition monitoring of PMs, for example, monitoring the temperature of PMs