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The radial force of the degradable esophageal stent before and after degradation is one of the important indicators for effective treatment of esophageal stricture. Based on a combination of in vitro experiments and finite element analysis, this paper studies and verifies the biomechanical properties of a new type of degradable esophageal stent under different esophageal stricture conditions. Under radial extrusion conditions, the maximum stress at the port of the stent is 65.25 MPa, and the maximum strain is 1.98%; The peak values of stress and strain under local extrusion and plane extrusion conditions both appear in the extrusion area and the compression expansion area at both ends, which are respectively 48.68 MPa, 46.40 MPa, 0.49%, 1.13%. The maximum radial force of the undegraded stent was 11.22 N, and 97% and 51% of the maximum radial force were maintained after 3 months and 6 months of degradation, respectively. The research results verify the safety and effectiveness of the radial force of the new degradable esophageal stent, and provide a theoretical basis for the clinical treatment of esophageal stricture.
Subject(s)
Humans , Esophageal Stenosis/surgery , Finite Element Analysis , Mechanical Phenomena , StentsABSTRACT
Percutaneous renal puncture device has very important clinical value. Qualified percutaneous renal puncture device is one of the important ways to evaluate its safety and efficacy, and it is also an important prerequisite for the device to be marketed in China. When manufactuers test the product, the selection of representative products is suggested from the aspects of performance parameter, structure, material and production process.
Subject(s)
Humans , China , Kidney , Nephrostomy, Percutaneous , PuncturesABSTRACT
Objective To analyze the clinical characteristics of patients with presbycusis by using disyllabic mandarin speech test materials (MSTMs).Methods A total of 59 subjects (23 men and 36 women) with presbycusis,from 61 to 84 years old with the average as 71.3±6.7.They were divided into three groups:the mild group (10 subjects),the moderate group (35 subjects)and the severe group (14 subjects)according to the pure tone average (PTA) thresholds at 0.5,1,2 and 4 kHz from the better ear.In addition,11 subjects of elderly persons with normal hearing were used as the control group.All the subjects enrolled in this study could speak Mandarin well in their daily lives.Nine lists of disyllabic mandarin speech test materials were utilized to test speech recognition threshold (SRT) and P-I function for these groups respectively.Results The PTA(51.65±11.98)and SRT (50.98±16.05)from presbycusis group were much higher than the control group(PTA 19.55± 4.55,SRT 18.79± 7.45),while the average slope of the P-I function 2.63％/dB from the presbycusis group was lower than the control group 4.65％/dB (P＜0.01).The SRT of male patients (56.54±17.23) was higher than the females(47.99± 15.63) (P＜0.05).The PTA and SRT in these three groups divided by degrees of hearing loss were higher than the control group obviously.The PTA and SRT had significantly increased as the degree of hearing loss increased.The differences among these groups were significant (P＜0.01).The average slope of P-I function of these three groups divided by degrees of hearing loss (mild group:2.47％/dB,moderate group:2.76％/dB,severe group:2.42％/dB) was smaller than the slopes in the control group which was 4.65 ％/dB (P＜0.01).The average slope of P-I function among these groups had no significant difference (P＞0.05).Conclusion The SRT of patients with presbycusis increased and the SRT of male was higher than the females.The average slope of P-I function decreased and the curve moved to right side and became a gradual curve.As hearing loss became more severe,the SRT rose more apparently.
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Objective To compare the performance of Mandarin screening version of hearing handicap inven-tory in elderly (HHIE-S)and the single question of hearing loss in the hearing screening in the old adults.Methods A total of 570 participants,aged from 50~85 years,of native Mandarin speakers were tested with standard pure tone audiometry (PTA),HHIE-S and single questionAre you now having difficulty in hearing?.HHIE-S>8 was taken as an indicator of hearing handicap.Sensitivity,specificity,negative predictive values and positive predic-tive values of both HHIE-S and single question inquiry when 0.5~4 kHz PTA average > 25 dB,>40 dB and >60 dB were compared.Results The prevalence was 83.9% (478)measured by PTA.The prevalence was 55.3%and 52.5% for HHIE-S and positive answer for single question,respectively.The sensitivity of HHIE-S when the participants grouped with 0.5~4 kHz PTA average > 25 dB,>40 dB and > 60 dB was 61%,85% and 96%, respectively,whereas the sensitivity of single question of the above 3 conditions was 58%,81% and 100%,respec-tively.The specificity of HHIE-S decreased with greater hearing loss.It was 72%,88% and 47% respectively for HHIE-S and 75%,61% and 50% for the single question.There was no significant difference either for sensitivity and specificity between the HHIE-S and the single question.Conclusion Both the Mandarin version of HHIE-S and single question are effective in the hearing screening of old adults.Depending on the purpose and availability of resources,one or both of them can be adopted.
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Objective To compare the results of manually -tested speech recognition threshold (SRT ) with automatically software -recorded SRT in the trial of Mandarin disyllabic test ,exploring the significance to the clini-cal applying .Methods 128 normal people of different ages without hearing loss and 57 workers exposed to noise in an automobile manufacturing was selected .These two group of volunteers speak mainly Mandarin in their daily life . MADSEN Conera (Danmark) clinical audiometr was applied .A group of double syllable word list with the same dif-ficulty of equivalence was used as test material .The initial presentation level was 20 dB HL higher than PTA .Then compared the results of manually -tested SRT with automatically software -recorded SRT .Results In the normal group ,the automatic value SRT was 7 .84 ± 3 .98 dB HL ,the manual value was 9 .19 ± 4 .47 dB HL ,and the average value of speech frequency threshold was 7 .63 ± 5 .78 dB HL .In the noise group ,the automatic value SRT was 6 .10 ± 8 .40 dB HL ,the manual value was 18 .81 ± 9 .52 dB HL ,and the average value of language frequency threshold was 27 .18 ± 19 .13 dB HL .There was significant difference between the values of SRT tested manually and recorded automatically (P<0 .01) .Conclusion There are differences between SRT valued manually and automatically .The SRT in people with normal hearing can be tested using automatic -recorded method .This method is convenient for screening in people without hearing loss .To exam in people with hearing loss ,the manual test is more appropriate .
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Objective To analyze the test results of persons with noise -induced hearing loss using disyllabic Mandarin speech test materials (MSTMs) .Methods 57 subjects with noise -induced hearing loss (noise group) were divided into three groups according to the duration of noise exposure :less than 10 years ,between 11 and 20 years and more than 20 years ,and also separated into 2 groups in terms of the degrees of hearing loss (group A :pure tone average thresholds of 0 .5 ,1 ,2 ,and 4 kHz less than or equal to 30 dB HL ,group B:pure tone average threshold of 0 .5 ,1 ,2 ,and 4 kHz greater than 30 dB HL) .66 subjects with normal hearing were in the control group .All the subjects enrolled in this study could speak Mandarin well in their daily life .Nine lists of disyllabic Mandarin speech test materials were utilized to test SRT and P -I function for these groups respectively .Results PTA and SRT in the noise group were much higher than the control group ,the average slope of P -I function was 5 .94% /dB ,and the curve of P-I function moved to the right side .SRT showed obvious changes as the increase of the years of noise exposure and especially in the group which had more than 20 years noise exposure (P<0 .01) . SRT of group B which had more hearing loss were greater than that of group A (P<0 .01) .Conclusion SRTs in the noise group are much higher than the control group with the average slope of P -I functions decreasing and the curve moving to the right side .As the years of noise exposure increase and the degrees of hearing loss become more severe ,SRT rise more apparently .
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OBJECTIVE@#To valuate test results of normal hearing persons with different ages using disyllabic mandarin speech test materials (MSTMs). Obtaining speech recognition threshold (SRT) and P-I function of different ages as clinical reference of hearing recovery and individual's ability to perceive and process speech.@*METHOD@#One hundred and twenty subjects with normal hearing who speak mandarin well in their daily lives were enrolled in this study and divided into four groups (18-30, 31-40, 41-50 and 51-60 years old). Nine lists of disyllabic mandarin speech test materials with equal difficulty were utilized to test each age group.@*RESULT@#There are good agreement between SRT and mean PTA thresholds (at 0.5, 1.0, 2.0, and 4.0 kHz) in each age group. PTA thresholds have little change as age increasing in age group 18-30, 31-40 and 41-50 (P > 0.05). PTA threshold of age group 51-60 increases more apparently compared with the other three groups (P < 0.01). SRT thresholds of each age group increase as age increasing (P < 0.05) and SRT threshold of age group 51-60 increases more apparently (P < 0.01). Slopes of P-I function in each age group are 5.8%/dB, 4.7%/dB, 3.8%/dB, 2.9%/dB respectively.@*CONCLUSION@#Nine lists of disyllabic MSTMs were used to test normal hearing persons in different ages and SRT and P-I function of four different age groups were obtained. As age increases, SRT increases and slope of P-1 functions decreases. PTA and SRT thresholds of age group 51-60 increase more apparently. The SRT and P-I functions provide reference data of normal hearing for utilizing of disyllabic mandarin speech test materials clinically.