Sizing the Depth and Width of Narrow Cracks in Real Parts by Laser-Spot Lock-In Thermography

We present a complete characterization of the width and depth of a very narrow fatigue crack developed in an Al-alloy dog bone plate using laser-spot lock-in thermography. Unlike visible micrographs, which show many surface scratches, the thermographic image clearly identifies the presence of a single crack about 1.5 mm long. Once detected, we focus a modulated laser beam close to the crack and we record the temperature amplitude. By fitting the numerical model to the temperature profile across the crack, we obtain both the width and depth simultaneously, at the location of the laser spot. Repeating the process for different positions of the laser spot along the crack length, we obtain the distribution of the crack width and depth. We show that the crack has an almost constant depth (0.7 mm) and width (1.5 µm) along 0.7 mm and features a fast reduction in both quantities until the crack vanishes. The results prove the ability of laser-spot lock-in thermography to fully characterize quantitatively narrow cracks, even below 1 µm.     

小鼠实验性肿瘤局部热图高温机制研究

研究表明：红外热图在肿瘤的诊断和疗效评估方面有其独特的价值。本文对实验性肿瘤动物模型发生、发展过程进行了动态的红外热图、病理形态观察及血浆ＮＯ含量、组织微血管密度检测。以肝癌（Ｈ２２）细胞接种于昆明小鼠后肢肌群建立肿瘤模型。实验小鼠随机分为两组：①肿瘤（Ｔｕ,ｎ＝８８）;②肿瘤对照组（Ｔｃ,ｎ＝８８）。结果：血浆ＮＯ含量和组织微血管密度随小鼠肿瘤生长持续增高,且与肿瘤区平均温度值呈显著正相关。提示：ＮＯ含量增高,肿瘤区微血管密度增高是肿瘤局部高温可能原因。     

功能锻炼对骨折愈合影响的红外实验与临床观察

为探讨相同负荷不同时间情况下应力对骨折愈合的影响,取同龄山羊５只,常规手术下造成桡骨横断骨折。采用测力式固定器加载固定,分别于７、１４、２１、２８、３５天处死,取出桡骨制成实验标本,做红外光谱分析。结果从骨痂的红外光谱中看到,反映有机质存在的吸收带Ｉ１的数值,与代表烃基磷灰石的吸收带Ｉ２、Ｉ３的数值比,１４－１５天内发生巨变,而Ｗｈｉｔｅ等对家兔胫骨不加载实验,骨痂强度跃度出现在２６天左右。由此看     

BeeFill^TM2in1热牙胶根充系统根充时牙根表面温度变化

目的：研究用红外成像仪监测BeeFill^TM2in1热牙胶根管充填系统根充时牙根表面温度的变化。方法：选取因牙周炎拔除的上下颌单根管中切牙22颗用BeeFill^TM2in1热牙胶根充系统进行根管充填。用红外成像仪跟踪监测从根充开始到完成这一过程中牙根表面温度的变化。结果：牙根表面温度根充后比根充前上颌中切牙平均升高8.2℃,低于引起周围组织损伤的理论阈值温度;下颌中切牙平均升高11.6℃,高于引起周围组织损伤的理论阈值温度。结论：本研究表明BeeFill^TM2in1热牙胶根充系统根充时会引起上、下颌中切牙牙根表面温度升高,但下颌中切牙牙根表面温度升高可能会造成牙周组织损伤,在临床上要谨慎使用。     

Anti-mycobacterial diynes from the Canadian medicinal plant Aralia nudicaulis

Ethnopharmacological relevance

Aralia nudicaulis, or wild sarsaparilla, is used as a traditional medicinal plant for the treatment of various illnesses by many of the Canadian First Nations. Iroquois and Algonquin First Nations of Eastern Canada use a tea prepared from dried Aralia nudicaulis rhizome as a cough medicine and for the treatment of tuberculosis. Previous investigations of aqueous extracts of Aralia nudicaulis rhizomes have shown it to possess antimycobacterial activity.

Aim of the study

To isolate and identify antimycobacterial constituents from Aralia nudicaulis rhizomes.

Materials and methods

Methanolic extracts of Aralia nudicaulis rhizomes were subjected to bioassay guided fractionation using the microplate resazurin assay (MRA) to assess inhibitory activity against Mycobacterium tuberculosis strain H37Ra. The antimycobacterial constituents were identified by NMR, MS and polarimetry.

Results

Two C17 polyacetylenes with significant antimycobacterial activity were isolated from the Aralia nudicaulis rhizome extract. The polyacetylenes were identified as (3R)-falcarinol and (3R, 9R, 10S)-panaxydol. Falcarinol and panaxydol displayed MICs of 25.6 μM and 36.0 μM and IC₅₀s of 15.3 μM and 23.5 μM against Mycobacterium tuberculosis H37Ra.

Conclusions

Falcarinol and panaxydol were identified as the principal constituents responsible for the antimycobacterial activity of Aralia nudicaulis rhizomes validating an ethnopharmacological use of this plant by the Canadian First Nations.     

Infrared thermographic SAR measurements of interstitial hyperthermia applicators: errors due to thermal conduction and convection

Thermal conduction and convection were examined as sources of error in thermographically measured SAR patterns of an interstitial microwave hyperthermia applicator. Measurements were performed in a layered block of muscle-equivalent phantom material using an infrared thermographic technique with varying heating duration. There was a 52.7%?reduction in maximum SAR and 75.5%?increase in 50%?iso-SAR contour area for a 60-s heating duration relative to a 10-s heating duration. A finite element model of heat transfer in an homogeneous medium was used to model conductive and convective heat transfer during the thermographic measurement. Thermal conduction artefacts were found to significantly distort thermographically measured SAR patterns. Convective cooling, which occurs when phantom layers are exposed for thermal image acquisition, was found to significantly affect the magnitude, but not the spatial distribution, of thermographically measured SAR patterns. Results from this investigation suggest that the thermal diffusion artefacts can be minimized if the duration of the applied power pulse is restricted to 10?s or less.     

大鼠海水浸泡体温过低症水浴复温的实验研究

目的 观察重度海水浸泡体温过低症大鼠不同热水浴复温成功率和复温曲线特征。方法 取490只雄性SD大鼠（实验前行温度记录器腹腔置入术）,随机分为浸泡组（450只）和对照组（40只）,浸泡大鼠在（15.0±0.2）℃海水中分别浸泡不同时长：2 h（100只）、5 h（150只）、10 h（200只）,每个浸泡时长的存活大鼠均随机分为5个亚组并给予相应的方法复温：被动复温（被动复温组）、37℃热水浴复温0.5 h（37℃主动复温0.5 h组）、37℃热水浴复温1 h（37℃主动复温1 h组）、42℃热水浴复温0.5 h（42℃主动复温0.5 h组）、42℃热水浴复温1 h（42℃主动复温1 h组）;对照组不进行海水浸泡,随机均分为4个亚组,分别给予上述4种不同方法的热水浴复温。计算各组的复温成功率;复温20 h后采集存活大鼠血清检测肌酸激酶同工酶（CK-MB）、丙氨酸转氨酶（ALT）、乳酸脱氢酶（LDH）水平;取出温度记录器读取动态腹腔温度数据,计算被动复温速度、热水浴复温迟发后降效应。结果 随着浸泡时间的延长,浸泡组大鼠低温海水浸泡存活率下降（P<0.05）,被动复温组及主动复温组的复温成功率均下降（P<0.05）,37℃主动复温1 h组大鼠复温成功率大于或等于其他主动复温组,且大于或等于被动复温组;对照组热水浴后均存活。存活大鼠血清CK-MB、ALT和LDH水平随着浸泡时间延长逐渐升高,主动复温组较对照组均升高（P<0.05）,在浸泡时长相同时,37℃主动复温1 h组的CK-MB、ALT和LDH水平低于其他主动复温组,且低于被动复温组,部分差异有统计学意义（P<0.05）。分析复温曲线,被动复温组复温速度随浸泡时间的延长而下降（P<0.05）,且死亡大鼠的复温速度低于存活大鼠（P<0.05）;热水浴复温大鼠腹腔温度可出现迟发后降效应,迟发后降总效应越大,死亡率越高;对照组37℃热水浴迟发后降效应不明显,42℃热水浴明显（P<0.05）。结论 在重度海水浸泡体温过低症的救治中,恰当的热水浴复温成功率大于被动复温。紧急情况下可以将热水浴作为一种复温选择,但不当的复温条件可降低救治成功率,其可能与迟发后降效应有关。     

家兔颈后肌受长期应力作用的实验研究

目的 建立颈后肌受长期应力作用动物模型并进行相关研究.方法 30只家兔随机分为模型组和对照组,每组15只.模型组家兔置于特制低头位框架中,低头角度为45度,每天1次,每次5小时;对照组除不低头外余条件相同.12周后分别进行颈椎X线、颈后部红外热像图、血清肌酸激酶和乳酸脱氢酶含量以及颈后肌超氧化物歧化酶和丙二醛含量观察.结果 模型组颈椎X线改变积分值实验后明显高于实验前和对照组,差异具有显著性;模型组与对照组颈后部红外热像图有明显差异;模型组血清肌酸激酶、乳酸脱氢酶的含量均明显高于对照组;模型组丙二醛含量明显高于对照组而超氧化物歧化酶含量明显低于对照组.结论 家兔颈后肌受长期应力作用后出现颈部的生物力学和生物化学失衡.     

具有红外线热扫描功能的人体表层血管显示仪的研制

目的:研制一种具有红外线热扫描功能的人体表层血管显示仪。方法:仪器设计有红外线热扫描功能的检测探头,探头对准人体表层皮肤后,其感光元件能感应人体表层皮肤和表层皮肤下的血管所辐射的红外线,进而将被测患者血管的静态分布图显示出来。结果:医生根据显示的血管分布图,可以快速地判定患者血管状况,实时准确地进行插管输液等必要的处理,该仪器是一种便携式诊疗工具。结论:该设备能便携、快速和准确地显示人体表层血管静态分布图,能帮助医护人员进行抢救、插管输液等医疗操作,安全、快捷、简单,值得推广应用。