Influence of rotational speed, torque and operator's proficiency on ProFile failures

AIM: The purpose of this study was to evaluate the influence of rotational speed, torque, and operator experience with a specific Ni-Ti rotary instrumentation technique on the incidence of locking, deformation and separation of instruments. METHODOLOGY: ProFile Ni-Ti rotary instruments (PRI) sizes 40-15 with a 6% taper were used in a crown-down technique. In one group of canals (n = 300) speeds of 150, 250 and 350 rpm (subgroups 1, 2 and 3) were used. Each one of the subgroups included 100 canals. In a second group (n = 300) torque was set at 20, 30 and 55 Ncm (subgroups 4, 5 and 6). In the third group (n = 300) three operators with varying experience (subgroups 7, 8 and 9) were also compared. Each subgroup included the use of 10 sets of PRI and 100 canals of extracted human molars. Each set of PRI was used in up to 10 canals and then sterilized before each case. NaOCl 2.5% was used as an irrigant. The number of locked, deformed, and separated instruments for the different groups, and within each part of the study was analysed statistically for significance with chi-squared tests. RESULTS: In group 1 only one instrument was deformed in the 150-rpm group and no instruments separated or locked. In the 250-rpm group instrument separation did not occur, however, a high incidence of locking, deformation and separation was noted in the 350-rpm group. In general, instrument sizes 30-15 locked, deformed and separated. Chi-squared statistics showed a significant difference between the 150 and 350 rpm groups but no difference between the 150 and 250 rpm groups with regard to instrument separation. Overall, there was a trend toward a higher incidence of instrument deformation and separation in smaller instruments. Locking and separation occurred during the final passage of the instruments, in the last (tenth) canal in each subgroup. In the second group, neither separation nor deformation and locking occurred during the use of the ProFile instruments, at 150 rpm, and at the different torque values. In the third group, chi-squared analysis demonstrated that significantly more instruments separated with the least experienced operator. Instrument locking, deformation, and separation did not occur with the most experienced operator. CONCLUSIONS: Preclinical training in the use of the PRI technique with crown-down at 150 rpm were crucial in avoiding instrument separation and reducing the incidence of instrument locking and deformation.     

温经通络汤联合针灸治疗风寒湿痹型关节炎的疗效及对患者血清Wnt-3α,β-catenin及BMP-2表达的影响

目的:探讨温经通络汤结合针灸治疗风寒湿痹型关节炎的疗效及对患者血清分泌型糖蛋白(Wnt)-3α,β-链蛋白(β-catenin)及骨形成蛋白-2(bone morphogenetic proteins-2,BMP-2)表达的影响。方法:选自天津中医药大学第一附属医院2015年2月—2016年11月收治的112例风寒湿痹型类风湿性关节炎(RA)患者,按照随机数字表将其分成观察组与对照组,每组56例。观察组给予温经通络汤联合针灸治疗,对照组给予塞来昔布联合来氟米特治疗,比较两组临床疗效、治疗前后中医临床证候积分、红细胞沉降率(erythrocyte sedimentation rate,ESR),C反应蛋白(C-reaction protein,CRP)及类风湿因子(rheumatoid factor,RF)变化情况以及血清Wnt-3α,β-catenin及BMP-2水平变化情况。结果:治疗后,观察组总有效率为94.64%,对照组总有效率为74.00%,观察组优于对照组(P0.01)。两组治疗后中医临床证候积分均较治疗前显著下降(P0.01),与对照组治疗后比较,观察组降低更显著(P0.01)。两组治疗后ESR,CRP,RF水平均较治疗前显著下降(P0.01),与对照组治疗后比较,观察组下降更显著(P0.05)。与治疗前比较,观察组治疗后血清Wnt-3α,β-catenin及BMP-2水平均显著下降(P0.01),对照组治疗前后比较无统计学差异。结论:温经通络汤结合针灸治疗风寒湿痹型关节炎疗效显著,其可下调Wnt-3α,β-catenin,BMP-2表达,缓解关节疼痛及改善关节功能。     

Design of a chattering-free integral terminal sliding mode approach for DFIG-based wind energy systems

This article proposes a Fuzzy Second Order Integral Terminal Sliding Mode (FSOITSM) control approach for DFIG-based wind turbines subject to grid faults and parameter variations. Since traditional terminal sliding mode control (SMC) suffers from singularity, a novel integral terminal sliding manifold is proposed to eliminate chattering and improve the wind turbine's performance in the presence of faults and disturbances. A fuzzy system is proposed to auto-tune the controllers' gains and ensures the invariance of the sliding surfaces even under heavy uncertainties, thus further improving the reliability and performance of the proposed controller. The performance of the proposed approach was assessed under various operating conditions. A comparison analysis with a standard SMC approach as well as the state of the art in voltage sag mitigation was also carried over. Reliability, robustness, and power availability under faulty grid conditions are among the main features of the proposed approach. In addition, the proposed approach exhibited chattering free dynamics and enabled the finite time convergence of the sliding manifold and overcame the singularity problem associated with standard TSMC.     

0.375%罗哌卡因不同注射速度对后入路腰方肌阻滞术后镇痛效果的影响

目的 探讨0.375%罗哌卡因不同注射速度对超声引导下后入路腰方肌阻滞术后镇痛效果的影响。
方法 拟在择期全麻下行腹腔镜Dixon直肠癌根治术患者60例,男40例,女20例,年龄35～70岁,BMI 18～30 kg/m²,ASA Ⅰ或Ⅱ级,采用随机数字表法分为两组：每侧注射速度40 ml/min组（H组）和每侧注射速度20 ml/min组（L组）,每组30例。全麻诱导前行超声引导下双侧后入路腰方肌阻滞,H组和L组每侧分别以40 ml/min和20 ml/min给予0.375%罗哌卡因20 ml。术后均行舒芬太尼PCIA。记录术中舒芬太尼用量和术后镇痛泵首次按压时间。记录术后4、8、12、24 h静息、运动时VAS疼痛评分、舒芬太尼用量、补救性镇痛例数。记录内脏损伤、局麻药中毒、穿刺血肿等并发症的发生情况。
结果 与L组比较,H组术中舒芬太尼用量明显减少,术后镇痛泵首次按压时间延长（P<0.05）;术后4、8、12、24 h静息、运动时VAS疼痛评分明显降低,舒芬太尼用量明显减少（P<0.05）;补救性镇痛例数明显减少（P<0.05）。两组均无内脏损伤、局麻药中毒、穿刺血肿等并发症发生。
结论 超声引导下后入路腰方肌阻滞中,0.375%罗哌卡因注射速度40 ml/min的术后镇痛效果优于20 ml/min。     

Linking internal and external signals for performance monitoring: An event‐related potential study

The present study explored the relevance of internal signals for the dynamics of personal and nonpersonal feedback processing. To this end, pairs of participants performed concurrently a choice‐response task and received external signals in four feedback contexts. In two contexts, feedback was informative about the personal performance (personal/private and personal/public); in the other two contexts, instructions suggested that feedback was informative about the other participant's performance (nonpersonal/other) or that it was random (nonpersonal/random). Since personal feedback was contingent on performance, the two contexts with personal feedback allowed a reference between internal and external signals. This reference significantly affected personal feedback processing. On the one hand, in the processing of personal feedback, the feedback‐related negativities (FRNs) evoked by feedback associated with distinctively fast or slow responses were less negative than the FRN elicited by feedback related to responses made with average speed. On the other hand, feedback signals evoked FRNs with similar amplitudes in the two contexts with nonpersonal feedback. Furthermore, personal and nonpersonal feedback elicited ERPs with different strength. Starting with the P2 potential, personal feedback evoked a more positive electrophysiological response than nonpersonal feedback. Based on these results, we conclude that a link between internal and external signals, as for personal feedback, is a key factor influencing the dynamics of feedback processing.     

Kinematics of 2 Reciprocating Endodontic Motors: The Difference between Actual and Set Values

Introduction

The aim of this study was to evaluate the kinematics of 2 reciprocating motors and compare it with manufacturers' declared values.

Methods

VDW Silver (VDW, Munich, Germany) and ATR Tecnika (Tecnika, Pistoia, Italy) were used in the study in 5 working modes: continuous rotation at 400 rpm on VDW Silver and ATR Tecnika and reciprocating motion on ATR Tecnika at 400 rpm and on VDW Silver in Reciproc and WaveOne mode. The polishing disk with an optical target was inserted in the contra-angle and recorded with a 1000–frames per second video camera. The direction and the amount of rotation were analyzed by computer, and the following kinematics parameters were calculated: engaging and disengaging angles, cycle rotational speeds, engaging and disengaging rotational speeds, net cycle angle, total cycle angle, and number of cycles to complete full rotation. One-way analysis of variance followed by planned pair-wise comparisons was used to compare kinematics parameters. The alpha error was set to 0.05.

Results

Analysis of variance revealed a difference between actual and set values of all 3 reciprocating modes in all kinematics parameters (P < .001). No significant difference between the actual engaging angle of Reciproc and that of the WaveOne mode was found. For reciprocating motion on the ATR Tecnika at 400 rpm, the actual engaging and disengaging angles were 8- and 9-fold greater, respectively, compared with set angles (P < .001).

Conclusions

The kinematics of reciprocating instrumentation is more complex than it seems as described only with angles and rotational speed. Actual kinematics values differ from manufacturers' declared values.     

口腔颌面部高速投射物伤致牙周膜间接损伤的实验研究

目的：研究口腔颌面部高速投射物伤导致的牙周膜间接损伤的特点。方法：将18只实验犬随机分为6组,以直径6．0 mm、质量0．88 g的高速投射物致伤右下颌骨体部第四前磨牙根尖下方区域,但不直接伤及牙齿;分别于伤后6h、24h、3d、7d、2w及4w处死实验犬,观察右下颌第四前磨牙、第二前磨牙及左下颌第二前磨牙牙周膜的组织病理学表现。结果：右下颌第四前磨牙和第二前磨牙的牙周膜损伤较明显,但病理学变化可逆;左下颌第二前磨牙牙周膜仅见一过性血管扩张、充血。结论：口腔颌面部高速投射物伤可导致牙周膜发生间接损伤,病理学变化可逆;损伤程度随着牙齿与伤区距离的增加而递减。     

持续颅内压监测下观察甘露醇不同输注速度的降压效果

目的了解不同速度静脉滴注甘露醇降压效果及作用维持时间。方法将需要定时使用甘露醇的患者随机分为3组，观察1组：10min内输完，观察2组：11～20min输完，观察3组：21～30min输完，分别在输注甘露醇前和输完甘露醇时、输完甘露醇后30min、输完甘露醇后6h记录颅内压（ICP）值，观察不同速度输注甘露醇患者ICP的变化。结果3组输完甘露醇后30min内患者的ICP都有下降，以观察1组变化的幅度最大。6h后患者ICP恢复至使用甘露醇前的水平。结论使用甘露醇降压时，输注速度越快，其降压效果越好，建议甘露醇使用的间隔时间以6h为宜。     

Frailty assessment of older adults,first-time applicants of public home care service in Norway

ObjectiveEarly detection of frailty is essential to prevent or delay disability. The most appropriate screening tool for frailty among home-dwelling older adults is under debate. The present study estimates the prevalence of frailty among older adults, first-time applicants of public home care service in Norway, and investigates the appropriateness of gait speed and Short Physical Performance Battery as screening-tools for frailty.Design and settingWe conducted a cross-sectional study of 116 older adults >65 years applying for public home care service for the first time. Frailty was assessed by an adapted version of the Fried Frailty Phenotype. The test accuracies of gait speed and Short Physical Performance Battery to detect frailty were calculated for a general population >70 years in Norway.Results62.1% of the participants were frail, 29.3% were prefrail, and 8.6% were robust. Mean gait speed and Short Physical Performance Battery-scores were significantly lower in frail compared to prefrail individuals, and significantly lower in prefrail compared to robust individuals. The sensitivity and specificity of gait speed at a cut point of 0.8 m/s to detect physical frailty phenotype was 99% and 68%, respectively.Conclusions The high prevalence of frailty in the present study indicates that screening for frailty should be considered at an earlier time point than when older adults apply for public home care service for the first time. Gait speed may be an appropriate screening tool for frailty in a general population >70 years in Norway.

KEY POINTS

• The prevalence of frailty among older adults, first-time applicants of public home care services in Norway is major.
• Screening for frailty should be considered before older adults apply for public home care service for the first time.
• Gait speed at a cut point at 0.8 m/s may be an appropriate screening tool for frailty in a general population >70 years in Norway.