scholarly journals Study of the Distortion of the Indirect Angular Measurements of the Calcaneus Due to Perspective: In Vitro Testing

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2585
Author(s):  
Isidoro Espinosa-Moyano ◽  
María Reina-Bueno ◽  
Inmaculada C. Palomo-Toucedo ◽  
José Rafael González-López ◽  
José Manuel Castillo-López ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Frontal Plane ◽  
In Vitro Study ◽  
Body Segment ◽  
The Real ◽  
Foot Progression Angle ◽  
Regression Formula ◽  
Angular Measurements ◽  
Kinematic Analyses

The study of the foot is relevant in kinematic analyses of gait. Images captured through a lens can be subjected to various aberrations or distortions that affect the measurements. An in vitro study was performed with a rearfoot simulator to compare the apparent degrees (photographed) with the real ones (placed in the simulator) in the plane of the rearfoot’s orientation, according to variations in the capture angle in other planes of space (the sagittal plane and transverse plane—the latter determined by the foot progression angle). The following regression formula was calculated to correct the distortion of the image: real frontal plane = 0.045 + (1.014 × apparent frontal plane) − (0.018 × sagittal plane × foot progression angle). Considering the results of this study, and already knowing its angle in the transverse and sagittal planes, it is possible to determine the angle of a simulated calcaneus with respect to the ground in the frontal plane, in spite of distortions caused by perspective and the lack of perpendicularity, by applying the above regression formula. The results show that the angular measurements of a body segment made on frames can produce erroneous data due to the variation in the perspective from which the image is taken. This distortion must be considered when determining the real values of the measurements.

scholarly journals Effects of occipital-atlas stabilization in the upper cervical spine kinematics: an in vitro study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
César Hidalgo-García ◽  
Ana I. Lorente ◽  
Carlos López-de-Celis ◽  
Orosia Lucha-López ◽  
Miguel Malo-Urriés ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
In Vitro Study ◽  
Upper Cervical Spine ◽  
Lateral Flexion ◽  
Alar Ligament ◽  
Before And After ◽  
Upper Cervical

AbstractThis study compares upper cervical spine range of motion (ROM) in the three cardinal planes before and after occiput-atlas (C0–C1) stabilization. After the dissection of the superficial structures to the alar ligament and the fixation of C2, ten cryopreserved upper cervical columns were manually mobilized in the three cardinal planes of movement without and with a screw stabilization of C0–C1. Upper cervical ROM and mobilization force were measured using the Vicon motion capture system and a load cell respectively. The ROM without C0–C1 stabilization was 19.8° ± 5.2° in flexion and 14.3° ± 7.7° in extension. With stabilization, the ROM was 11.5° ± 4.3° and 6.6° ± 3.5°, respectively. The ROM without C0–C1 stabilization was 4.7° ± 2.3° in right lateral flexion and 5.6° ± 3.2° in left lateral flexion. With stabilization, the ROM was 2.3° ± 1.4° and 2.3° ± 1.2°, respectively. The ROM without C0–C1 stabilization was 33.9° ± 6.7° in right rotation and 28.0° ± 6.9° in left rotation. With stabilization, the ROM was 28.5° ± 7.0° and 23.7° ± 8.5° respectively. Stabilization of C0–C1 reduced the upper cervical ROM by 46.9% in the sagittal plane, 55.3% in the frontal plane, and 15.6% in the transverse plane. Also, the resistance to movement during upper cervical mobilization increased following C0–C1 stabilization.

The Mechanics of Cervical Muscle Recruitment on Cervical Spine Stability —A Biomechanical in Vitro Study using Porcine Model

2008 ◽  
Vol 24 (1) ◽  
pp. 63-68 ◽  
Author(s):  
C.-H. Cheng ◽  
T.-Y. Chen ◽  
Y.-W. Kuo ◽  
J.-L. Wang
Keyword(s):  
Cervical Spine ◽  
Muscle Force ◽  
Sagittal Plane ◽  
In Vitro Study ◽  
Spinal Stability ◽  
Muscle Recruitment ◽  
Spine Stability ◽  
Cervical Muscles ◽  
The Stability

ABSTRACTCervical muscles are crucial in providing the stability of the cervical spine. Many in vitro studies have investigated the relationship between muscle force and stability directly. However, the effects of different muscle dysfunctions or muscle recruitments on cervical spine stability are not yet clear and therefore, worthy of study. A spine testing apparatus with muscle force replication activated by pneumatic cylinders was developed to find the effect of muscles on spinal stability. Seven porcine cervical spines (C2-T1) were used. Three pairs of cervical muscles, including neck flexors (sternocleidomastoid, SCM) and neck extensors (splenius capitis, SPL; semispinalis capitis, SSC), were simulated. The experimental tests included: 1. no muscle recruitment, 2. full muscle recruitments, 3. SCM dysfunction, 4. SPL dysfunction, and 5. SSC dysfunction. The external pure moment in sagittal plane was applied from 0 Nm to 2 Nm to examine the stability/flexibility of specimens. The spinal stability was evaluated by the neutral zone (NZ), the range of motion (ROM), the reduced NZ (R_NZ), and the reduced ROM (R_ROM). Loading responses of C7-T1 disc were also measured. The results of this study showed: The activation of cervical muscles decreased the NZ and ROM. The degree of decrease among different muscle dysfunctions, however, was not significantly different. The SPL dysfunction induced larger anterior shear force, while the SCM dysfunction exclusively induced extension moment. In conclusion, the muscle forces could stabilize the cervical spine, but significant decrease in spinal stability was not found among dysfunctions of different muscles. The SCM and SPL dysfunction may result in abnormal stress at the C7-T1 disc.

scholarly journals Comparison between Two Radiological Methods for Assessment of Tooth Root Resorption: An In Vitro Study

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Sabina Saccomanno ◽  
Pier Carmine Passarelli ◽  
Bruno Oliva ◽  
Cristina Grippaudo
Keyword(s):  
Root Resorption ◽  
In Vitro Study ◽  
Clinical Settings ◽  
Radiographic Image ◽  
Panoramic Radiographs ◽  
The Real ◽  
Radiological Images ◽  
Digital Methods ◽  
Radiological Methods

Purpose. This study aims to verify the validity of the radiographic image and the most effective radiological techniques for the diagnosis of root resorption to prevent, cure, and reduce it and to verify if radiological images can be helpful in medical and legal situations. Methods. 19 dental elements without root resorption extracted from several patients were examined: endooral and panoramic radiographs were performed, with traditional and digital methods. Then the root of each tooth was dipped into 3-4 mm of 10% nitric acid for 24 hours to simulate the resorption of the root and later submitted again to radiological examinations and measurements using the same criteria and methods. Results. For teeth with root resorption the real measurements and the values obtained with endooral techniques and digital sensors are almost the same, while image values obtained by panoramic radiographs are more distorted than the real ones. Conclusions. Panoramic radiographs are not useful for the diagnosis of root resorption. The endooral examination is, in medical and legal fields, the most valid and objective instrument to detect root resorption. Although the literature suggests that CBCT is a reliable tool in detecting root resorption defects, the increased radiation dosage and expense and the limited availability of CBCT in most clinical settings accentuate the outcome of this study.

In vitro study of the interaction between human gut microbiota and herbal extracts using willow bark extract as an example

Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381
Author(s):  
EM Pferschy-Wenzig ◽  
K Koskinen ◽  
C Moissl-Eichinger ◽  
R Bauer
Keyword(s):  
Gut Microbiota ◽  
In Vitro Study ◽  
Vitro Study ◽  
Bark Extract ◽  
Herbal Extracts ◽  
Human Gut ◽  
Human Gut Microbiota ◽  
Willow Bark

In Vitro Effects of Urokinase — Prevention by Different Inhibitors

1990 ◽  
Vol 64 (03) ◽  
pp. 402-406 ◽  
Author(s):  
M D Oethinger ◽  
E Seifried
Keyword(s):  
In Vitro Study ◽  
Thrombin Time ◽  
Plasma Samples ◽  
Temperature Dependent ◽  
Chloromethyl Ketone ◽  
Control Value ◽  
Dose Time ◽  
In Vitro Effects ◽  
Full Protection

SummaryThe present in vitro study investigated dose-, time- and temperature-dependent effects of two-chain urokinase plasminogen activato(u-PA, urokinase) on normal citrated plasma. When 10 μg/ml u-PA wereadded to pooled normal plasma and incubated for 30 min at an ambient temperature (25° C), α2-antiplas-min decreased to 8% of the control value. Incubation on ice yielded a decrease to 45% of control,whereas α2-antiplasmin was fully consumed at 37° C. Fibrinogen and plasminogen fell to 46% and 39%, respectively, after a 30 min incubation at 25° C. Thrombin time prolonged to 190% of control.Various inhibitors were studied with respect to their suitability and efficacy to prevent these in vitro effects. Aprotinin exhibited a good protective effect on fibrinogen at concentrations exceeding 500 KlU/ml plasma. Its use, however, was limited due to interferences with some haemostatic assays. We could demonstrate that L-Glutamyl-L-Glycyl-L-Arginyl chloromethyl ketone (GGACK) and a specific polyclonal anti-u-PA-antibody (anti-u-PA-IgG) effectively inhibited urokinase-induced plasmin generation without interfering with haemostatic assays. The anti-u-PA-antibody afforded full protection ofα2-antiplasmin at therapeutic levels of u-PA.It is concluded that u-PA in plasma samples from patients during thrombolytic therapy may induce in vitro effects which should be prevented by the use of a suitable inhibitor such as GGACK or specific anti-u-PA-antibody.

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