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Acid value, as an important indicator of its oxidation and quality, is used to measure the content of free fatty acid (FFA) in edible vegetable oil. At present, titration is the most widely used method to examine the acid value of edible oil, which is simple and easy to operate. Titration is effective for the detection of acid in most edible oils, but the detection error rate is higher for edible oil with lower acid value, darker color or certain interference components except FFA. Instrumental analysis methods, such as spectroscopy,electrochemistry, colorimetry and chromatography, can be used as alternatives to titration. Besides, the instrumental analysis methods have better sensitivity and accuracy. In order to further expand and innovate the technology of acid value detection in edible vegetable oil, the production pathway of edible vegetable oil FFA, the features and current situation of acid value detection methods are analyzed and compared, to provide reference for the improvements of acid value detection method and the establishment of new methods.

Manipulating single cells with a micropipette is the oldest, yet still a widely used technique. This paper discusses the aspiration of a single cell into a micropipette and positioning the cell accurately to a target position inside the micropipette. Due to the small volume of a single cell (picoliter) and nonlinear dynamics involved, these tasks have high skill requirements and are labor intensive in manual operation that is solely based on trial and error and has high failure rates. We present automated techniques in this paper for achieving these tasks via computer vision microscopy and closed-loop motion control. Computer vision algorithms were developed to detect and track a single cell outside and inside a micropipette for automated single-cell aspiration. A closed-loop robust controller integrating the dynamics of cell motion was designed to accurately and efficiently position the cell to a target position inside the micropipette. The system achieved high success rates of 98% for cell detection and 97% for cell tracking (n = 100). The automated system also demonstrated its capability of aspirating a single cell into a micropipette within 2 s (versus 10 s by highly skilled operators) and accurately positioning the cell inside the micropipette within 8 s (versus 25 s by highly skilled operators). [ABSTRACT FROM PUBLISHER]

Objective To learn about past experiences in studying ideological and political theory courses of doctoral students in Peking Union Medical College and the actual teaching outcomes of Selected Readings of Marxist Classics after the implementation of the teaching reform. Methods Two sets of questionnaires were distributed to 530 MD candidates of Grade 2019 before and after the course in order to investigate and compare their cognition, attitude and evaluation. Results In the pre-course survey, 462 valid questionnaires were recovered, and the recovery rate was 87.17%. In the after-course survey, 466 effective questionnaires were recovered, and the recovery rate was 87.92%. Most students' recognized the significance of this course and were satisfied with the teaching methods and assessment methods. Conclusions Medical students have a good reading and learning experience in this course. However, it is required to continuously strengthen humanistic care in ideological and political teaching to enhance students' sense of gain and further improve their political and moral qualities from the perspective of cognition, feeling and action.

Objective: To study the value of multiple Helicobacter pylori (H.pylori) antibody detection by protein array in the diagnosis of H.pylori infection in children., Methods: Biopsy specimens obtained by gastroscopy from 120 children with digestive system symptoms were detected by rapid urease test (RUT) and modified Giemsa staining. Positivity in both RUT and Giemsa staining was the "gold criterion" of H.pylori infection. Serum samples of these patients were obtained and the antibodies against cytotoxin associated gene A protein (CagA), vacuolating toxin A (VacA), urease, heat shock protein 60 (Hsp60) and RdxA (nitroreductase) were detected by protein array technique., Results: H.pylori infection was identified according to the "gold criterion" in 60 children. Compared with the "gold criterion", the goodness of fit and the coefficient of contingency in the diagnosis of H.pylori infection of the following four groups antibody detection were all statistically significant (P<0.001): anti-Ure antibody alone, anti-Ure antibody combined with anti-CagA antibody, anti-Ure antibody combined with anti-VacA antibody and anti-Ure antibody combined with anti-CagA and anti-VacA antibody. The sensitivity, specificity and accuracy of the detection of anti-Ure antibody combined with anti-CagA antibody for the diagnosis of H.pylori infection were 81.7%, 91.7% and 86.7%, respectively. The antibody detection showed a high positive predictive value (90.7%) and a high negative predictive value (83.3%)., Conclusions: The antibody detection by protein array, especially the detection of anti-Ure antibody combined with anti-CagA antibody, is valuable in the diagnosis of H.pylori infection.

Objective: Infection with clarithromycin-resistant Helicobacter pylori (Hp) is often predictive of treatment failure. Susceptibility testing for Hp could guide therapy of Hp infections. However, agar dilution approved by the Clinical and Laboratory Standards Institute (CLSI) to test for antimicrobial susceptibility of Hp is time consuming (results are often not available in a week or more). So a more expeditious method is necessary. The purpose of this study was to evaluate polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) test performed directly on gastric biopsy specimen from children to detect 23S rRNA mutations (A2143G and A2144G) indicating clarithromycin resistance., Methods: All biopsy specimens were derived from patients presenting with upper gastrointestinal symptoms, submitted to endoscopy in the Affiliated Children's Hospital, Zhejiang University School of Medicine from September 2006 to February 2007. No patients had undergone eradication therapy. Thirty-nine samples randomly selected from positive specimens by rapid urease test, were homogenized in 500 microl brucella broth with 30% glycerol. The 200 microl homogenized fluid was used to purify genomic DNA with the kit according to the instructions provided by manufacturer, and the rest was used to isolate Hp strains by culturing. All the Hp isolates were tested for clarithromycin susceptibility with the agar dilution and classified as resistant if the minimum inhibitory concentrations (MIC) exceeded 1 microg/ml. Simultaneously, PCR-RFLP analysis was performed in order to identify 23S rRNA mutations (A2143G and A2144G). Finally, the two methods were compared by statistics. The agar dilution was used as a standard to determine the sensitivity and specificity of the PCR-RFLP assay., Results: Of the 39 samples, agar dilution and PCR-RFLP method respectively detected 13 (33.3%) and 14 (35.9%) clarithromycin-resistant gastric specimens. The sensitivity and specificity of PCR-RFLP for the detection of Hp in biopsy specimens were both 92%. The positive and negative predictive value was 85.7% and 96% respectively. No statistically significant difference was found between the two methods (chi2=0.06, P>0.05). The rate of Hp resistance to clarithromycin significantly increased compared with a previous report from the authors' hospital in 2004 (chi2=6.20, P<0.05)., Conclusions: Rising clarithromycin resistance rates were observed in children who visited the authors' hospital. PCR-RFLP test is reliable and rapid for detection of clarithromycin resistance directly on gastric biopsy specimen from children and may help choose appropriate antibiotic in Hp eradication therapy.

Objective: To evaluate the benefits of biofeedback therapy in children with functional constipation caused by pelvic floor dysfunction (PFD)., Method: Anorectal manometry (PC Polygraf HR, Medtronic) was performed in children with functional constipation according to the diagnostic criteria of Rome III. Among them, 47 cases with PFD were trained with biofeedback therapy (PC Polygraf HR, Medtronic) according to the degree of cooperation. They received the treatment twice every week, and those in whom the therapy was performed at least three times were enrolled to evaluate the efficacy in this study., Result: A total of 27 cases (20 male and 7 female) in whom the procedure was performed at least three times were eligible for inclusion into this study. The mean age of them was (6.7 + or - 2.2) years (range 4 to 12 years), and the mean duration of symptoms was (3.0 + or - 2.3) years with a range of 6 months to 8 years. Among them, 16 cases received the biofeedback training more than 5 times, while 8 cases more than 7 times. The rectal maximum contraction pressure during defecation was increased significantly with the number of biofeedback training before treatment and after 3, 5, and 7 times of treatment was (36.2 + or - 10.4), (45.1 + or - 9.5), (47.6 + or - 9.1), and (47.8 + or - 8.8) mm Hg (1 mm Hg = 0.133 kPa) respectively (P < 0.01). The potential of electromyography of external anal sphincter decreased progressively, but had not reached significance. Follow-up continued for 3 to 12 months by telephone, the clinical response to biofeedback treatment was evaluated as excellent (complete resolution of constipation), good (improvement of constipation), partial or poor (no improvement of constipation). The response was excellent in 13 cases (48.1%), good in 8 (29.6%), partial in 3 (11.1%), and 2 (7.5%) cases had no improvement, and 1 case was lost to follow-up, and the rate of success was 88.9% (24/27)., Conclusion: Biofeedback therapy is a safe and effective treatment option for functional constipation due to PFD in children probably by increasing the rectal maximum contraction pressure during defecation.

Objective: To investigate the role of oxidative stress in the pathogenesis of esophageal mucosa injury in children with reflux esophagitis (RE)., Methods: Esophageal mucosal samples from 36 children with RE (7 months to 16 years of age) were obtained by gastroscopy. The parameters of oxidative stress, including the contents of malondialdehyde (MDA), glutathione (GSH) and nitric oxide (NO) and total superoxide dismutase (T-SOD) activity in the esophageal mucosa as well as the protein content of the esophageal mucosa, were measured. Twenty children (3 to 16 years of age) without esophageal mucosal injury by gastroscopy served as controls., Results: There was no significant difference in the protein content of the esophageal mucosa between the RE and the control groups. The content of MDA in the RE group (15.36+/- 16.67 nmol/mg) was significantly higher than that in the control group (7.51+/- 6.17 nmol/mg) (P<0.01). The activity of T-SOD in the RE group (30.43+/- 35.09 U/mg) was statistically lower than that in the control group (56.34+/- 51.73 U/mg) (P<0.05). No significant differences were observed in GSH and NO contents between the two groups., Conclusions: The MDA content increases and the SOD content decreases in the esophageal mucosa in children with RE. This suggests that oxidative stress seems to be an important mediator in generation of esophageal mucosal injury.