BACKGROUND: Although nickel and chromium are essential elements of human body, over high concentration of them will produce many adverse effects to human body, therefore biological safety of nichrome material for dental restoration deserves attention.OBJECTIVE: To observe the changes of nickel and chromium content at 6 months and 1 year after porcelain-fused-to-nichrome crown restoration, and compare to healthy controls to investigate the long-term safety of nichorme in oral cavity.DESIGN, TIME AND SETTING: A case-control observation was performed between January 2006 and December 2007 at the First Affiliated Hospital of Hebei North University, Zhangjiakou, Hebei Province, China.PARTICIPANTS: Sixty patients who visited Department of Stomatology, the First Affiliated Hospital of Hebei North University, between January and December 2006 were included in test group, including 28 male, 32 female, the mean age was 40 years. Each of them had 3 anterior maxillary teeth restored by porcelain-fused-to-nichrome crowns, without other metal fillings or protheses. Sixty healthy cases visited the hospital at the same time were used as control, including 30 male, 30 female, the mean ages was 39 years.METHODS: Fasting venous blood of participants in two groups was harvested sterilely at 6 months and 1 year after test group restoration, serum nickel and chromium content were determined using graphite furnace atomic absorption spectrometry.MAIN OUTCOME MEASURES: ① Serum nickel content changes in test and control group. ②Serum chromium content changes in test and control groupRESULTS: All cases were involved in result analysis. ① Serum nickel content changes in test and control group: At 6 months postrestoration, there was no significant difference in serum nickel content between test group and control group (P>0.05). At 1 year after restoration, serum nickel content of test group was significantly higher than that of control group (P<0.05). ② Serum chromium content changes in test and control group: There was no significant difference in chromium content between test and control group at 6 months and 1 year after test group restoration (P>0.05).CONCLUSION: Nickel and chromium released from porcelain-fused-to-nichrome crowns after restoration under oral environment, serum nickel content had an increasing tendency with the prolongation of restoration time, but in small quantity and within biosafety range, to identify whether the increasing tendency will increased continuously with the prolongation of restoration time needs long-term follow-up.

0.05). Conclusion:After Ni-Cr-Based porcelain-fused-to-metal crown application, the metal ion can be released and absorbed by human body. But the content is almost harmless to human body.

Objective to investigate the current status of preoperative anxiety level and explore the influencing factors in elderly patients with pros-tatic hyperplasia. Methods A total of 124 patients with prostatic hyperplasia were selected for the study,and the State-trait Anxiety Inventory (StAI)was analyzed using the convenience sampling method. Results the score were 55.54±4.81 for SAI,34.60±2.09 for tAI,and 90.14±5.91 for StAI. the preoperative anxiety level of patients with prostatic hyperplasia varied in different demography(P < 0.05). According to multiple lin-ear stepwise regression equation,age,cultural level,place of residence,and the medical burden are the influence factors. Conclusion the preoper-ative anxiety level of elderly patients with prostatic hyperplasia is high,and more health education is needed. It is necessary to use different psycholog-ical persuasion according to their specific situation,so as to promote their physical and mental health,and to promote the effect of postoperative recov-ery.

A novel method based on cross sensitivity of cataluminescence (CTL) on nano-Ti3CeY2O11 was proposed for simultaneous determination of formaldehyde, benzene and sulfur dioxide in air.The relations between the concentrations of formaldehyde, benzene and sulfur dioxide and their CTL intensities were respectively ascertained at three wavelengths.The accurate concentrations of formaldehyde, benzene and sulfur dioxide can be calculated by superimposed total CTL intensities.The three analysis wavelengths are 420 nm, 535 nm and 680 nm.The surface temperature of the sensitive materials is 280℃.The carrier gas flow rate is 130 mL/min.The detection limits (3σ) are 0.04 mg/m3 for formaldehyde, 0.05 mg/m3 for benzene and 0.10 mg/m3 for sulfur dioxide, respectively.The linear ranges of CTL intensity versus analyte concentration are 0.08-75.60 mg/m3 for formaldehyde, 0.1-101.40 mg/m3 for benzene and 0.3 to 115.00 mg/m3 for sulfur dioxide.The recoveries of 12 testing standard samples by this method are 96.4%-103.7% for formaldehyde, 97.8%-102.5% for benzene and 97.2%-103.3% for sulfur dioxide.Common coexisting substances, such as acetaldehyde, toluene, hydrogen sulfide, ammonia, methanol, ethanol and carbon dioxide, do not disturb the determination.The relative deviation of CTL signals of continuous 200 h detection for gaseous mixture containing formaldehyde, benzene and sulfur dioxide is less than 2%, which shows the longevity of the nanometer composite oxide to formaldehyde, benzene and sulfur dioxide.This method makes full use of the cross sensitive phenomenon, and can realize the on-line analysis of formaldehyde, benzene and sulfur dioxide in air.

Objective To inverstigate the effect and safety of refractory intrahepatic and extrahepatic bile duct stones treated by choledochoscope holmium laser combined with electrohydraulic lithotripsy.Methods The cllnical data of 67 cases of postoperative intrahepatic and extrahepatic bile duct stones treated with combined endoscopic holmium laser and electrohydraulic lithotripsy were analysed retrospectively.Results After 1 to 7 times of biliary endoscopic holmium laser electrohydraulic lithotripsy treatment,65 patients had complete removal of all residual stones with the success rate of 97%,and without complications.Conclusions After holmium laser combined with electrohydraulic lithotripsy,the effect of choledochoscopic removal of intrahepatic and extrahepatic bile duct residual stones can be greatly improved It is a safe method for treatment of refractory intra-and extra-hepatic bile duct stones.

Objective:To investigate the effect of pelvic motion in late pregnancy on the outcome of first trimester delivery.Methods:A total of 127 first-borns admitted to the midwifical clinic of Nanjing Maternal and Child Health Hospital from November 1, 2019 to March 10, 2020 were selected as the research objects, and they were divided into the walking group and the pelvic motion group according to the random number table method. In the end, 62 cases were included in the walking group and 65 cases in the pelvic motion group. The walking group did brisk walking in the third trimester. In the pelvic motion group, the motion in the third trimester consisted of the combined pelvic motion involving the two planes of the upright spine and the horizontal spine, and multiple peripelvic joints. The changes of fertility, birth canal and fetus before and after exercise were observed, and the outcomes of childbirth were compared between the two groups.Results:Indicators reflecting productivity: persistence time of "air bike" on the day before delivery was (27.12±7.73) seconds in the pelvic motion group and (20.56±6.60) seconds in the walking group, the difference was statistically significant ( t value was 5.12, P<0.01). The time of contractions after exercise before delivery was (269.38±123.70) seconds in the pelvic motion group and (591.29±201.82) seconds in the walking group, the difference was statistically significant ( t value was 10.89, P<0.01). The indicators reflecting the situation of the maternal birth canal were as follows: "sitting forward flexion level", pelvic motion group was (33.64±5.91) cm, walking group was (29.50±5.28) cm, the difference was statistically significant ( t value was 4.15, P<0.01). The cervical score during regular contractions was 8.01±1.69 in the pelvic motion group and 7.30±1.40 in the walking group, the difference was statistically significant( t value was 2.56, P<0.05). At the beginning of regular contractions, the proportion of fetal "occipital position" was 93.85% (61/65) in the pelvic motion group and 72.58%(45/62) in the walking group, the difference was statistically significant ( χ2 value was 10.41, P<0.01). The "no pain rate after exercise the day before delivery" was 72.31% (47/65) in the pelvic motion group and 29.03% (18/62) in the walking group, the difference was statistically significant ( χ2 value was 25.30, P<0.01). Time of the first labor was (395.84±165.24) min in the pelvic motion group and (574.35±152.23) min in the walking group, the difference was statistically significant ( t value was 6.32, P<0.01). The second stage of labor was (25.98±9.88) min in the pelvic motion group and (33.62±13.94) min in the walking group, the difference was statistically significant ( t value was 3.57, P<0.01). Conclusions:Pelvic motion in middle and late pregnancy can affect labor force, birth canal, fetus and other delivery factors, reduce movement pain and shorten the time of labor.

A highly sensitive magnetic enzymE-linked chemiluminescent immunoassay method was developed for the detection of human chorionic gonadotropin(HCG). The monoclonal antibody was covalently coupled on the surface of carboxylated magnetic beads to generate magnetic-biotargeting; Alkaline phosphatase(ALP) was utilized as a labeled reagent of another monoclonal antibody, whereas 3-(2-spimadamantane) 4-methoxy-4-(3-phosphoryloxy)phenyl-1,2-dioxetane(AMPPD) was utilized as the chemiluminescent substrate. Based on this concept, a highly sensitive chemiluminescent immunoassay method was established to test HCG. Then, several modifications were made to optimize the method, and the detection sensitivity and procedure were improved accordingly. The detection of the assay could be fulfilled within 60 min and the test result of HCG concentration was linear over the range of 0.15 150 IU/L with good relativity(r=0.960). The relative standard deviation(RSD) were below 5% and the sensitivity of this method was 0.15 IU/L. The proposed method with wide linear range, simple operation and fast detection showed good prospect in practical application on-site.

The magnetic nanoparticle probe was prepared by specifically connecting the streptavidin-conjugated magnetic nanoparticles and the antibody of analyte via the strong streptavidin-biotin interaction. Based on the magnetic nanoparticle probes, the concentration of human chorionicgonadotropin (HCG) was detected and a new CL method for of hormone was further established. The performances of the magnetic nanoparticle probes were characterized by UV-Vis spectrometry, transmission electron microscopy and dynamic light scattering. The experimental conditions that affected the chemiluminescence were optimized. The optimal concentrations of luminal and H_2O_2 were 2×10~(-4) mol/L and 8×10~(-4) mol/L, respectively, and optimal pH was 13. Under the optimized experiment conditions, a linear response of chemiluminescence intensity to HCG concentration was obtained with a correlation coefficients of 0.9924. The linear range was from 0.5 to 250 μg/L and wider than the conventional ELISA method (5-200 μg/L). The relative standard deviation was 3.8%. Correlation analysis showed that there was significant correlation between the method of magnetic nanoparticle probes and ELISA in 34 clinical samples. The proposed method with characters of sensitive, effective, fast response and wide detection range provided good application prospect in analysis of other ultra-micro protein.

Several key problems were analysed for the transdermal noninvasive glucose monitoring. A modified calibration equation was proposed for the high-sensitivity glucose biosensor due to its narrow linear range. The new equation has increased the sensors' linear range by 20 times. A new diffuse model was constructed for the electrode system of glucose sensor,aiming at the unique "finite space" electrochemical problem in trans-dermal technique. In addition,electrode masks were utilized to solve the problem of electrode loss in longtime glucose monitoring. In animal in-vivo experiments,70.1 % of the noninvasive glucose data points were clinically accurate,while the remains were clinically acceptable. All solutions mentioned above were based on both theoretical analysis and experimental validation,promoting the realization and optimization of transdermal noninvasive glucose monitoring techniques.

Objective:To investigate the effects of riboflavin-ultraviolet A scleral collagen cross-linking on the retina under different irradiation time, and to determine the safe irradiation time.Methods:Sixty healthy New Zealand white rabbits were randomly divided into control group (0 minute group), 10 minutes group, 20 minutes group, 30 minutes group and 40 minutes irradiation group according to the irradiation time, with 12 rabbits in each group.The left eye was irradiated with riboflavin-ultraviolet A scleral collagen (370 nm, 10 mW/cm 2). The histopathological change of retina was observed by light microscope and transmission electron microscope and compared among different groups.The concentration of MDA and the activities of SOD, CAT and GSH-Px in retinal tissue were detected by corresponding kits.The expression levels of SOD and CAT proteins in retinal tissue were detected by Western blot method.The study protocol was approved by the Binzhou Medical University Laboratory Animal Ethical Committee (No.2017-80). The use and care of animals complied with the statement of ARVO and the Regulation on the Management of Laboratory Animal Quality of China. Results:Under the light microscope, the structure of the retinas in the control group was orderly arranged.Under the transmission electron microscope, the lamellar structure in the inner segment and the mitochondrial structure in the outer segment of the photoreceptor cells were intact, and the mitochondrial ridge was continuous in the control group.There was no obvious difference in retinal morphology between the 10 minutes irradiation group and the control group under both the light microscope and the transmission electron microscope, and the retinal damage became more severe with the prolongation of irradiation time.The concentration of MDA in the retina of each group was elevated gradually with the increase of irradiation time, and the difference was statistically significant ( F=65.25, P<0.05). The concentration of MDA was (11.31±1.84), (14.94±1.04)and (18.25±1.42)nmol/mgprot in the 20 minutes, 30 minutes and 40 minutes irradiation groups respectively, which were significantly higher than (1.13±0.02)nmol/mgprot in the control group (all at P<0.05). The MDA concentration in 20 minutes, 30 minutes and 40 minutes irradiation groups was increased successively, showing statistically significant differences (all at P<0.05). With the prolongation of irradiation time, the activities of SOD, CAT and GSH-Px as well as the expression levels of SOD and CAT proteins were significantly decreased gradually ( F=44.09, 34.18, 35.60, 115.75, 78.86; all at P<0.05). The differences between the control group and 20 minutes, 30 minutes, 40 minutes irradiation groups, and the differences among 20 minutes, 30 minutes, 40 minutes irradiation groups were statistically significant (all at P<0.05). Conclusions:Riboflavin-ultraviolet A 10 mW/cm 2 scleral collagen cross-linking irradiation for 10 minutes is safe.Excessive irradiation time can cause damage to the retina of rabits.