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Objective:To investigate the predictive value of stone composition prediction method based on dual-source stone energy spectrum CT for uric acid stones.Methods:The clinical data of 204 patients with urinary stones, 159 males and 45 females, admitted to Shanghai Sixth People's Hospital from July 2020 to July 2022 were retrospectively analyzed. The average age was (50.7±14.3) years. There were 187 cases of upper urinary tract (kidney, ureter) stones and 17 cases of lower urinary tract (bladder, urethra) stones. All patients underwent preoperative dual-source stone energy spectroscopy CT, measuring CT values at 150 kV and 100 kV, respectively, and the calculated dual energy ratio (Ratio) was used to predict stone composition. Of the 204 cases in this group, 33 cases underwent percutaneous nephrolithotomy and 171 cases underwent ureteroscopic lithotripsy. Postoperative stone specimens were analyzed for stone composition by infrared spectroscopy. Subject work characteristic (ROC) curves were used to analyze the efficacy of preoperative dual-source stone energy spectrum CT to predict uric acid stones.Results:In 204 patients, preoperative CT predicted 28 cases of uric acid stones and 176 cases of non-uric acid stones, including 136 cases of calcium oxalate stones, 38 cases of hydroxyapatite, and 2 cases of cystine stones. Postoperative IR spectral analysis detected 26 cases of uric acid stones and 178 cases of non-uric acid stones, including 129 cases of calcium oxalate stones, 47 cases of hydroxyapatite, and 2 cases of cystine stones. Compared with the preoperative CT results, there were 2 false positives and no false negatives in the classification of uric acid stones. The ROC curve showed that the sensitivity of the CT value for predicting uric acid stones at 100 kV was 96.2%, the specificity was 99.5%, and the area under the ROC curve (AUC) was 0.995, with the best prediction value of 620 HU.The sensitivity of the CT value for predicting uric acid stones at 150 kV was 96.2%, specificity was 85.5%, AUC was 0.916, and the best predictive value was 597.5 HU. The sensitivity of using Ratio values for predicting uric acid stones was 100.0%, specificity was 97.9%, AUC was 0.996, and the best predictive value was 1.14. The CT values for uric acid stones at 100 kV and 150 kV were (558.58±77.07) HU and (521.12±83.54) HU, CT values for calcium oxalate stones were (1 335.26±301.82) HU and (878.21±200.21) HU, CT values for hydroxyapatite were (1 104.09±203.61) HU and (710.38±178.44) HU, respectively.The CT values of cystine stones were (684.5±67.18) HU and (573.5±67.10) HU, respectively, and the differences between uric acid stones and other components were statistically significant ( P<0.01). The Ratio values of uric acid stones, calcium oxalate stones, hydroxyapatite, and cystine stones were 1.08±0.06, 1.52±0.08, 1.62±0.40, and 1.19±0.02, respectively, and the differences were statistically significant ( P<0.01) when comparing uric acid stones with other components. Conclusion:The CT and Ratio values of dual-source stone energy spectrum CT can effectively distinguish uric acid stones from other types of stones, and the accuracy, sensitivity, and specificity of this method for predicting uric acid stones are high.
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Objective:To establish the quantitative relationship equation of the crantiofacial vertical points in the skeletal classⅡ malocclusion patients with various vertical types by using genetic algorithms method,and to express the measured values in the patients with different gender with the same formula.Methods:A total of 155 skeletal class Ⅱ malocclusion patients without treatment,aged from 10 to 18 years old,were selected and divided into high-angle group(n=50),average-angle group(n=58),low-angle group(n=47);5 samples were randomly selected in each group as the test samples,the rest as the experimental sample.The cephalometic radiographs were performed and measured.The relevant influencing factors of craniofacial structure were ensured.The genetic algorithm was used to optimize the equation parameters to obtain the correlation equation.The error between the predicted value and the measured value was compared.Results:The various parameters had no significant differences between different gender in high-angle,average-angle and low-angle groups(P>0.05);then the men and the women with same type were combined,most of the indicators had statistically significant differences between three groups (P0.05).Conclusion:The quantitative relationship equation of the crantiofacial vertical points in the skeletal class Ⅱmalocclusion patients with various vertical types established with genetic algorithms may show the vertical quantitative relationship and predict the growth to a certain degree.
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Objective:To optimize the parameters of the equation of sagittal craniofacial structures with different classes of malocclusion using genetic algorithms(GAS), and to explore the rules .Methods:A total of 240 patients with average angle malocclusion aged 8-18 years old were divided into three groups: Angle Class Ⅰ(n=79), Angle Class Ⅱ(n=76)and Angle Class Ⅲ(n=85) groups.In each group 10 cases were randomly selected as the test samples, the rest as the experimental samples.The cephalometric analysis was performed on all the patients'' cephalograms, and the results of Ba-N,Ba-A,Ba-S,S-Ptm,Ptm-A,Ba-Ar,Ar-Go,Go-PoG,Ba-PoG and N-S-Ar were analyzed by two independent samples t-test and One-Way ANOVA. The relevant influencing factors of craniofacial structures were found.The parameters of the equation was optimized to obtain the relevant equations using GAS.The predicted values of the optimized equation were compared with the measured values.Results:There were no significant differences in sex between Angle Class Ⅰ, Class Ⅱ and Class Ⅲ groups(P> 0.05);when the men and women with the same type were combined,the Ba-A,Ptm-A,Ar-Go,and Ba-PoG had statistically significant differences between Angle Class Ⅰ, Class Ⅱ, and Class Ⅲ groups (P 0.05), and the error was small.Conclusion: The optimal relation equation of craniofacial structure of sagittal malocclusion is established by GAS with the quantitative regularity.
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<p><b>OBJECTIVE</b>Frictions of Lock-loose brackets with ligated main wings or all six wings were measured as they slid along archwires in dry and artificial saliva environments. The Lock-loose brackets were then compared with traditional brackets and self-ligating brackets.</p><p><b>METHODS</b>The surface states of the stainless steel archwires were observed with atomic force microscopy before and after mechanical traction. The Lock-loose brackets, traditional brackets, and self-ligating brackets used in this study were composed of 0.406 4 and 0.457 2 mm stainless steel round archwires and 0.457 2 mm x 0.634 9 mm and 0.482 6 mm x 0.634 9 mm stainless steel rectangular archwires. Two different ligating methods were applied to the Lock-loose brackets, i.e., main wings ligated and all six wings ligated. Frictions were measured by using an electronic universal testing machine.</p><p><b>RESULTS</b>No significant differences were found between the roughness of different archwires before and after mechanical traction in different brackets (P > 0.05). When the main wings of the Lock-loose brackets were ligated, the frictions of the four different stainless steel archwires were close to zero, and the difference with frictions of traditional brackets was significant (P < 0.05). When using 0.457 2 mm x 0.634 9 mm rectangular archwires, maximum friction (P < 0.05; significantly different from those of other brackets) was reached when all six wings of the Lock-loose brackets were ligated. Frictions in the dry state were higher than those in the wet state (P < 0.05).</p><p><b>CONCLUSION</b>The Lock-loose brackets can adjust the friction efficiently with different ligating methods, thus solving the problem of low friction and strengthening anchorage.</p>
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Humans , Friction , Materials Testing , Microscopy, Atomic Force , Orthodontic Appliance Design , Orthodontic Brackets , Orthodontic Wires , Stainless Steel , Surface PropertiesABSTRACT
Objective To establish an equation between canine and other permanent teeth,and probe a new method to predict the sum of the mesiodistal diameters of unerupted permanent canines.Methods Samples consisted of 118 dental casts were obtained from Chinese patients(50 males,68 females,respectively).Mesiodistal tooth diameters were measured by a vernier caliper.GAS was used to establish the equation between canine and other permanent teeth,and compared with stepwise regression analysis.Those were modelling samples that optimized equations coefficient(112 samples).Others were inspection samples(6 samples).Results The equation between canine and other permanent teeth was established.MU=0.0511U1+0.2164U2+0.2780U4+0.0407U5+0.2853U6+0.8321①;ML=0.2998U1+0.1294U2+0.3912U4+0.0088U5+0.0791U6+0.9839②;FU=0.1419U1+0.1741U2+0.3258U4+0.0412U5+0.093U6+1.7355③;FL=0.2796U1+0.3750U2+0.2968U4+0.0268U5+0.0043U6+0.6030④.Compared with stepwise regression analysis,the mean error of precision by GAS was less(P