Variable Venting Valve for Earmolds

The frequency response and loudness reduction characteristics of earmolds with variable venting valves (VVV) were investigated. Both side-branch and laterally vented earmolds were employed. Sound pressures were measured at 44 frequencies from 100 to 4 000 Hz in a modified HA-2 coupler with the VVV in four stages of opening: closed; ? open; ? open and 3/3 open

The effect of venting is primarily in the low frequencies. Little or no reduction in intensity is observed in the ‘speech frequency’ range and a modest amount is noted in the higher frequencies. The side-branch vented earmolds were more effective than the laterally vented earmolds. Calculated loudness reductions in phons were small. The effectiveness of the VVV, whether assessed by the frequency response or loudness reduction characteristics, is achieved within the first ? of opening: further opening has little effect. The utility of the VVV, especially to the geriatric hearing aid user, is questionable     

使用一次性输液器组件中排气针服用中药汤剂

目的将一次性输液器组件中排气针用于老年患者中药汤剂的服用,确保安全服用,减少浪费。方法使用剪好的一次性输液器组件中排气针(用剪刀剪下针头一侧和滤网一侧)为126例老年患者服用中药汤剂。结果使用一次性输液器组件中排气针为患者服用中药汤剂2963次,均确保了安全服用,无床单污染、咳呛现象。结论使用一次性输液器组件中排气针为患者服用中药汤剂的方法简单、方便、实用,节省了服用中药的时间,减少了不必要的护理工作,为老年患者提供了方便。     

Effect of low-frequency gain and venting effects on the benefit derived from directionality and noise reduction in hearing aids

When the frequency range over which vent-transmitted sound dominates amplification increases, the potential benefit from directional microphones and noise reduction decreases. Fitted with clinically appropriate vent sizes, 23 aided listeners with varying low-frequency hearing thresholds evaluated six schemes comprising three levels of gain at 250 Hz (0, 6, and 12 dB) combined with two features (directional microphone and noise reduction) enabled or disabled in the field. The low-frequency gain was 0 dB for vent-dominated sound, while the higher gains were achieved by amplifier-dominated sounds. A majority of listeners preferred 0-dB gain at 250 Hz and the features enabled. While the amount of low-frequency gain had no significant effect on speech recognition in noise or horizontal localization, speech recognition and front/back discrimination were significantly improved when the features were enabled, even when vent-transmitted sound dominated the low frequencies. The clinical implication is that there is no need to increase low-frequency gain to compensate for vent effects to achieve benefit from directionality and noise reduction over a wider frequency range.     

不同时机左心引流对婴儿体外循环肺保护作用的研究

目的探讨不同时机左心引流对婴儿体外循环肺保护的作用。方法 81例≤10个月的先天性心脏病患儿,分成三组,N1组体外循环开始即刻开启左心引流,术毕,心排量恢复后停止;N2组主动脉阻断,心脏停跳后开启左心引流,结束与N1组相同;N3组左心引流开始时间与N1组相同,心内操作结束后停止。比较三组体外循环前及结束时、术后1h、6h血清肿瘤坏死因子-α(TNF-α)、白介素-6(IL-6)的浓度、气道峰压(Ppeak)、气道平压台(Pplate)、肺水含量(TAF)、氧合指数(OI)及术后呼吸机辅助通气时间。结果 N1组体外循环后TNF-α、IL-6的浓度及Ppeak、Pplate及TAF较其他组明显下降(P0.05),OI则明显增高(P0.05),呼吸机辅助通气时间较其他组明显缩短(P0.05)。结论早开始、晚结束左心引流能减轻婴幼儿体外循环肺损伤,具有良好的肺保护作用。     

Physical and Subjective Correlates of Earmould Occlusion

Physical and subjective aspects of earmould occlusion are examined and related. In particular, measurements made in an ear-like coupler for various venting arrangements are compared with those obtained subjectively by a loudness balance procedure. The results demonstrate the effectiveness of an open (completely non-occluding) earmould at low-frequency sound reduction but indicate some of the factors which make its individual effect difficult to predict. It is further seen the group of hearing-impaired persons was less able to make systematic judgements on sound quality than was the control group of normally hearing persons.

Les facteurs physiques et subjectifs intervenant lors de l'emploi d'embouts d'appareils de correction auditive occlusifs ont été etudies et rapportés. Ont été comparés, en particulier, les mesures faites avec une oreille artiflcielle dans laquelle ont été aménagés plusieurs types d'ouvertures et les résultats obtenus subjectivement par balance alternée de la sonie. Les résultats démontrent l'efficacité de l'embout ouvert (sans occlusion aucune) pour les basses fréquences; mais, ils révèlent également un certain nombre de facteurs qui montrent que son effet peut varier d'un individu à l'autre. Nos résultats ont montré, par ailleurs, que les personnes souffrant de troubles de l'audition éprouvaient plus de difficultés à émettre des appréciations systématiques sur la qualité du son que le groupe témoin, composé de personnes jouissant d'une audition normale.     

An Analysis of the Effect of a Vent Hole on Excess Cement Expressed at the Crown–Abutment Margin for Cement-Retained Implant Crowns

Purpose: The labial margins of anterior implant‐retained crowns are often positioned subgingivally for a superior esthetic appearance. One of the consequences of subgingival margins is the increased risk of leaving excess cement behind following cementation. This can lead to potential problems, including peri‐implant inflammation, soft tissue swelling, soreness, bleeding or suppuration on probing, and bone loss. The purpose of this laboratory study was to investigate the effect of placement, location, and diameter of a vent hole on the amount of cement being expressed at the margin of an anterior implant abutment‐retained crown. Materials and Methods: Three implant crown copings were fabricated to fit on the same custom abutment. Three vent diameters (0.75, 1.25, and 1.65 mm) and three locations on the palatal surface of the coping (cervico‐palatally, mid‐palatally, inciso‐palatally) were chosen for vent hole placement. For each test, the coping was cemented onto the abutment under standardized conditions. A preweighed thin coating of cement was applied to the fit surface of the coping. The amount of cement expressed at the margin and vent hole was measured by weight and calculated as a proportion of the amount of cement placed in the coping before seating. The procedure was completed 15 times for each variable. The results were statistically analyzed using univariate ANOVA with post hoc Bonferroni‐adjusted independent samples t‐tests. Results: The presence of a vent hole influenced the proportion of cement expressed at the coping margin (p < 0.05). The location of a vent hole influenced the proportion of cement expressed at the coping margin (p < 0.05), with the exception of the mid‐palatal and inciso‐palatal positioning where there was no significant difference (p= 0.61) between groups. The diameter of the vent hole did not significantly influence the proportion of cement expressed at the coping margin (p= 0.096). Conclusions: When using anterior cement‐retained implant crowns, the use of a 0.75‐mm mid‐palatal or inciso‐palatal vent hole to minimize the amount of cement expressed at the margin during cementation should be considered.     

左心引流对离体大鼠心肌影响

目的 本实验的目的是研究左心引流的心肌保护作用。方法 将健康SD大鼠随机分为两组：左心引流组（A组）和对照组（B组，不建立左心引流）建立改良式Langendorff离体鼠心灌注模型，将大鼠离体心脏置于模型中，A组做相当于左心引流效应的干预，对B组则不进行任何干预处理。记录干预前、恢复后5、10、20、30、60分钟测定心功能指标（LVEDP、LVESP、LVDP、dP／dt），CK-MB含量，全程心电活动以及左室心内膜下心肌组织送电镜检查。结果 左心引流组和对照组在心肌舒张收缩功能、心肌酶CK-MB的指标具有显著性差异（P〈0．05），心肌的电镜超微结构也有明显的不同。结论 左心引流对心肌有更好的保护作用（P〈0．05）。     

左心引流对离体大鼠心肌影响

目的本实验的目的是研究左心引流的心肌保护作用。方法将健康 SD 大鼠随机分为两组:左心引流组(A组)和对照组(B 组,不建立左心引流)建立改良式 Langendorff 离体鼠心灌注模型,将大鼠离体心脏置于模型中,A 组做相当于左心引流效应的干预,对 B 组则不进行任何干预处理。记录干预前、恢复后5、10、20、30、60分钟测定心功能指标(LVEDP、LVESP、LVDP、dP/dt),CK-MB 含量,全程心电活动以及左室心内膜下心肌组织送电镜检查。结果左心引流组和对照组在心肌舒张收缩功能、心肌酶 CK-MB 的指标具有显著性差异(P<0.05),心肌的电镜超微结构也有明显的不同。结论左心引流对心肌有更好的保护作用(P<0.05)。