A Brief History of Mechanical Stress and the Method of Experimental Micromechanics with the Raman Microprobe

Background: Exit-site infection (ESI) is a common complication in peritoneal dialysis (PD) patients. Clearly understanding the risk factors may be useful for the prevention of ESI. This study was to explore the prevalence and risk factors of ESI in incident PD patients. Methods: We evaluated ESI in incident PD patients who had catheter insertion in our center between 1 January 2009 and 31 December 2013, with follow-up for 1 year. We collected data on demographics, clinical features, and nursing care methods of the exit site (ES). Results: We recruited 1133 incident PD patients (687 male (60.6%); mean age 47.0 ± 15.1 years), and 245 (21.6%) had diabetes. Median follow-up was 12.0 months. One hundred and thirty-one patients had 139 episodes of ESI with a rate of 92.8 patient-months per episode (0.13 episodes per year). Coagulase-negative staphylococcus was the main pathogen, accounting for 33.8% of the ESIs. Gram-positive rods, Staphylococcus aureus, Pseudomonas, fungi, and other organisms accounted for 23.0%, 15.8%, 1.4%, 1.4%, and 2.9%, respectively. No bacterial growth was found in 15.1%. There were no differences in demographic and laboratory data (age, gender, primary kidney disease, hemoglobin, white blood cell, serum albumin, blood urea nitrogen, serum creatinine, and C-reactive protein) between the ESI and non-ESI groups. Poor competency of ES care, poor catheter immobilization, history of catheter-pulling injury, and mechanical stress on the ES were significantly associated with increased risk of ESI. Conclusions: The prevalence of ESI was 0.13 episodes per year. Poor competency of ES care, catheter mobilization, history of catheter-pulling injury, and mechanical stress by waist belt or the protective bag of PD on ES were risk factors for ESI.

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Subchondral Insufficiency Fracture of the Femoral Head Caused by Excessive Lateralization of the Acetabular Rim

Case Reports in Orthopedics ◽

10.1155/2016/4371679 ◽

2016 ◽

Vol 2016 ◽

pp. 1-5

Author(s):

Tetsuya Kimura ◽

Tomohiro Goto ◽

Daisuke Hamada ◽

Takahiko Tsutsui ◽

Keizo Wada ◽

...

Keyword(s):

Femoral Head ◽

Mechanical Stress ◽

Insufficiency Fracture ◽

Severe Osteoporosis ◽

Mri Findings ◽

Subchondral Insufficiency Fracture ◽

Plain Radiographs ◽

History Of ◽

Acetabular Rim ◽

Acetabular Overcoverage

We present a case of a 53-year-old woman with subchondral insufficiency fracture (SIF) of the femoral head without history of severe osteoporosis or overexertion. Plain radiographs showed acetabular overcoverage with excessive lateralization of the acetabular rim. A diagnosis of SIF was made by typical MRI findings of SIF. The lesion occurred at the antipodes of the extended rim. Increased mechanical stress over the femoral head due to impingement against the excess bone was suspected as a cause of SIF. The distinct femoral head deformity is consistent with this hypothesis. This is the first report of SIF associated with acetabular overcoverage.

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POS0143 POST-STRESS ULTRASOUND ASSESSMENT OF THE ACHILLES TENDON IS USEFUL TO DIFFERENCIATE PSORIATIC ARTHRITIS FROM THE PHYSIOLOGICAL ADAPTATION TO EXERCISE

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.3897 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 283.2-283

Author(s):

C. Guillén-Astete ◽

V. García García ◽

N. García-Montes ◽

Á. Andreu-Suárez

Keyword(s):

Psoriatic Arthritis ◽

Achilles Tendon ◽

Mechanical Stress ◽

Morphological Changes ◽

Power Doppler ◽

Heel Pain ◽

Ultrasound Scan ◽

History Of ◽

Low Activity ◽

Power Doppler Signal

Background:Achilles enthesitis is the most accessible psoriatic arthritis hallmark to assess through ultrasound scan. Recently it has been demonstrated that continuous mechanical stress such as experimented by runners can drive to the development of physiological morphological changes that resembles those observed in psoriatic arthritis. In a subject with the suspicious diagnostic of psoriatic arthritis who practice any sports associated to continuous impact over the heels, the challenge to determine in what extent the morphological changes are linked to the exercise or to the disease, is remarkable.Objectives:To determine morphological differences between patients with psoriatic arthritis, trained runners and sedentary volunteers through ultrasound scan of the Achilles tendon.Methods:An ultrasound scan of the Achilles tendon was performed to the following subjects: Patients with diagnosis of psoriatic arthritis with a DAPSA score of low activity in at least six months and with history of heel pain in the past, volunteers runners with not less of 3-year sport activity at least three times a week and sedentary volunteers. In the group of patients, ultrasound scan was performed over the feet with history of heel pain. In the case of volunteers, the ultrasound scan was performed in the dominant feet. The selection of volunteers was not randomly-based in order to match their age and sex to the patients as much as possible. Besides demographic features, a comparison between tendon thickness at the level of the calcaneus bone border and the height of the retrocalcaneus bursae in the longitudinal axis were performed through ANOVA test. Power Doppler signal was scaned in all subjects before and after a controlled mechanical stress of the Achilles tendon by climbing stairs (100 steps, two times).Results:Female/male distribution of the group of patients, runners and sedentary people were: 12/10, 18/18 and 20/18, respectively. Achilles tendon mean thickness ± standard deviation was 6.61 ± 1.05, 5.91 ± 1.44 and 4.61 ± 2.1mm, respectively (P=0.01). Retrocalcaneus bursae height was 3.42 ± 0.21, 3.22 ± 0.27 and 2.21 ± 0.31 (P=0.01). Basal PD signal was present into the enthesis of 2/22, 1/36 and 0/38, respectively (P not significant). After exercise, PD signal was present in 8/22, 5/36 and 0/38, respectively (P<0.001).Conclusion:Power Doppler signal after exercise was identified as the most relevant ultrasound hallmark to distinguish a patient with psoriatic arthritis from a trained runner, even when psoriatic arthritis were considered as low activity. Post exercise ultrasound scan should be considered as a diagnosis tool in sportsmen with suspicious of psoriatic arthritis, until further studies confirm our findings.Disclosure of Interests:None declared

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Electric signal emissions during repeated abrupt uniaxial compressional stress steps in amphibolite from KTB drilling

Natural Hazards and Earth System Science ◽

10.5194/nhess-7-149-2007 ◽

2007 ◽

Vol 7 (1) ◽

pp. 149-154 ◽

Cited By ~ 26

Author(s):

D. Triantis ◽

C. Anastasiadis ◽

F. Vallianatos ◽

P. Kyriazis ◽

G. Nover

Keyword(s):

Mechanical Stress ◽

Laboratory Experiments ◽

Acoustic Emissions ◽

Uniaxial Stress ◽

Electric Signal ◽

Electric Currents ◽

Loading Cycle ◽

Compressional Stress ◽

History Of ◽

Loading And Unloading

Abstract. Laboratory experiments have confirmed that the application of uniaxial stress on rock samples is accompanied by the production of weak electric currents, to which the term Pressure Stimulated Currents – PSC has been attributed. In this work the PSC emissions in amphibolite samples from KTB drilling are presented and commented upon. After having applied sequential loading and unloading cycles on the amphibolite samples, it was ascertained that in every new loading cycle after unloading, the emitted PSC exhibits lower peaks. This attitude of the current peaks is consistent with the acoustic emissions phenomena, and in this work is verified for PSC emissions during loading – unloading procedures. Consequently, the evaluation of such signals can help to correlate the state and the remaining strength of the sample with respect to the history of its mechanical stress.

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