Non-invasive fluid pressure loading mitigating bone loss in disuse osteoporosis

Stresses in a bimetal strip of white metal bonded to steel, to simulate a journal bearing shell or a thrust bearing ring, have been calculated for various loading conditions. The stresses arose from: fluid pressure loading on the bearing surface whilst the back was supported on a complete rigid surface; locating and holding forces, e.g. compression due to nipping-up the bearing; elastic deformation of the bearing housing; differential thermal expansion and temperature gradients, and incomplete support of the bearing shell when subjected to fluid pressure on its bearing surface. Points at which fatigue damage is likely to originate are apparent. The stresses were calculated numerically from displacements which were found, by an iterative method, to satisfy a finite difference analogue of the governing differential equations.

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Pathophysiology of bone loss in disuse osteoporosis

Joint Bone Spine ◽

10.1016/j.jbspin.2011.04.007 ◽

2011 ◽

Vol 78 (6) ◽

pp. 572-576 ◽

Cited By ~ 61

Author(s):

Christian Alexandre ◽

Laurence Vico

Keyword(s):

Bone Loss ◽

Disuse Osteoporosis

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Non-invasive Estimation of Cerebrospinal Fluid Pressure Waveforms by Means of Retinal Venous Pulsatility and Central Aortic Blood Pressure

Annals of Biomedical Engineering ◽

10.1007/s10439-012-0563-y ◽

2012 ◽

Vol 40 (9) ◽

pp. 1940-1948 ◽

Cited By ~ 13

Author(s):

S. Mojtaba Golzan ◽

Mi Ok Kim ◽

Amir Saied Seddighi ◽

Alberto Avolio ◽

Stuart L. Graham

Keyword(s):

Blood Pressure ◽

Cerebrospinal Fluid ◽

Fluid Pressure ◽

Cerebrospinal Fluid Pressure ◽

Non Invasive ◽

Aortic Blood ◽

Aortic Blood Pressure ◽

Central Aortic Blood Pressure

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A Handheld Noninvasive Sensing Method for the Measurement of Compartment Pressures

Volume 2: Control, Monitoring, and Energy Harvesting of Vibratory Systems; Cooperative and Networked Control; Delay Systems; Dynamical Modeling and Diagnostics in Biomedical Systems; Estimation and Id of Energy Systems; Fault Detection; Flow and Thermal Systems; Haptics and Hand Motion; Human Assistive Systems and Wearable Robots; Instrumentation and Characterization in Bio-Systems; Intelligent Transportation Systems; Linear Systems and Robust Control; Marine Vehicles; Nonholonomic Systems ◽

10.1115/dscc2013-3847 ◽

2013 ◽

Author(s):

C. Flegel ◽

K. Singal ◽

R. Rajamani

Keyword(s):

Compartment Syndrome ◽

Fluid Pressure ◽

Magnetic Field Measurement ◽

In Vitro Test ◽

Non Invasive ◽

Fluid Compartment ◽

Combat Casualty ◽

The Individual ◽

Compartment Pressures

Compartment syndrome is a major concern in cases of extremity trauma, which occur in over 70% of military combat casualty. Without treatment, compartment syndrome can lead to paralysis, loss of limb, or death. This paper focuses on the development of a handheld sensor that can be used for the non-invasive diagnosis of compartment syndrome. Analytical development of the sensing principle is first presented in which a relation is obtained between the pressure in a fluid compartment and the stiffness experienced by a handheld probe pushing on the compartment. Then a handheld sensor that can measure stiffness of an object without requiring the use of any inertial reference is presented. The handheld sensor consists of an array of three miniature force-sensing spring loaded pistons placed together on a probe. The center spring is chosen to be significantly stiffer than the side springs. The ratio of forces between the stiff and soft springs is proportional to the stiffness of the soft object against which the probe is pushed. Small mm-sized magnets on the pistons and magnetic field measurement chips are used to measure the forces in the individual pistons. Experimental results are presented using an in-vitro test rig that replicates a fluid pressure compartment. The sensor is shown to measure pressure accurately with a resolution of 0.1 psi over the range 0.75 psi to 2.5 psi.

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Architectural modifications and cellular response during disuse-related bone loss in calcaneus of the sheep

Journal of Applied Physiology ◽

10.1152/jappl.1996.80.1.198 ◽

1996 ◽

Vol 80 (1) ◽

pp. 198-202 ◽

Cited By ~ 16

Author(s):

T. Thomas ◽

L. Vico ◽

T. M. Skerry ◽

F. Caulin ◽

L. E. Lanyon ◽

...

Keyword(s):

Bone Loss ◽

Cellular Response ◽

Disuse Osteoporosis ◽

Os Calcis ◽

Osteoblastic Activity ◽

Regional Effects ◽

Local Bone ◽

Bone Biopsies ◽

Strain Gauge Measurements ◽

Trabecular Number

The results of simple biomechanical unloading in models of acute-disuse osteoporosis are influenced by systemic and regional effects of the method used to generate the bone loss. A model in which strain-gauge measurements confirmed that the os calcis was unloaded in healthy ewes during ambulation was assessed by histomorphometry. Twelve nonovariectomized adult female Welsh mountain sheep were submitted to hock joint immobilization by an external fixation procedure from the tibia to the metatarsus for a period of 12 wk. Histomorphometric analysis showed that this model was able to produce pure local bone loss, as transiliac bone biopsies failed to reveal any difference between the initial and final results. Immobilized and nonimmobilized calcanei were both removed postmortem. After the 12 wk of the study, osteoclastic activity was increased in accordance with the usual disuse process. An unexpected increase of osteoblastic activity was also observed, possibly related to recovery after the initial dramatic bone loss, but an artifact of the surgical procedure such as a regional acceleration phenomenon cannot be definitively excluded. However, the increased osteoblastic activity was not sufficient to prevent accentuation of the negative bone balance, resulting in a 29% decrease of trabecular bone volume in immobilized calcanei compared with nonimmobilized calcanei. This reduction was due to thinning of trabeculae (72.4 +/- 12.1 vs. 98.9 +/- 15.9 microns; P < 0.05) without any change in trabecular number (2.74 +/- 0.72 vs. 2.79 +/- 0.40/mm2; not significant). In conclusion, this model only locally increased both osteoclastic and osteoblastic activities leading to bone loss and architectural modifications. The decreased bone formation usually observed in other models of disuse osteoporosis may therefore not constitute a local phenomenon generated by unloading.

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Enhanced alveolar bone loss in a model of non-invasive periodontitis in rice rats

Oral Diseases ◽

10.1111/j.1601-0825.2011.01893.x ◽

2012 ◽

Vol 18 (5) ◽

pp. 459-468 ◽

Cited By ~ 16

Author(s):

JI Aguirre ◽

MP Akhter ◽

DB Kimmel ◽

J Pingel ◽

X Xia ◽

...

Keyword(s):

Bone Loss ◽

Alveolar Bone ◽

Alveolar Bone Loss ◽

Non Invasive

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Pharmacokinetic (PK) and pharmacodynamic (PD) study of the effect of imatinib (Ima) on tumor (T) vascularity (V) and on gemcitabine (Ge) uptake (U) using non-invasive dynamic contrast enhanced (DCE) magnetic resonance imaging (MRI) and spectroscopy (MRS)—Study BUS228

Journal of Clinical Oncology ◽

10.1200/jco.2006.24.18_suppl.12006 ◽

2006 ◽

Vol 24 (18_suppl) ◽

pp. 12006-12006

Author(s):

W. Wolf ◽

C. A. Presant ◽

V. Waluch ◽

E. J. Chen

Keyword(s):

Accumulation Rate ◽

Phase 1 ◽

Fluid Pressure ◽

Post Contrast ◽

Dce Mri ◽

Chemotherapy Drugs ◽

Non Invasive ◽

Contrast Enhanced ◽

Magnetic Resonance Imaging Mri ◽

Moderate Nausea

12006 Background: Ima has been reported to increase T U of other chemotherapy drugs and to reduce interstitial fluid pressure (IFP) in experimental animals. Poplin et al performed a phase 1 analysis of Ima plus Ge in solid tumors (AACR 95:405, 2004). We tested ImaGe to determine the T PK and PD effects of Ima, Ge, and the ImaGe combination using DCE-MRI and MRS. Methods: Patients (pt) with measurable and MRI-imagible refractory solid T possibly responsive to Ge were randomized to receive either: one course of Ima with PK/PD, followed by one course of Ge with PK/PD, followed by the combination ImaGe; or one course of Ge with PK/PD followed by one course of Ima with PK/PD, followed by ImaGe. Ge was given at 900 mg/m2 IV over 30 min. for PK/PD and at 10 mg/m2/min. for continued therapy. Ima was given at 400 mg daily for 5 d. with Ge given on day 3. Doses were adjusted for toxicity. T V was measured by the use of DCE-MRI, as described previously (AACR 95:490,2004), where the initial contrast accumulation rate (ICAR) was calculated as the slope of the influx curve, and the delayed contrast accumulation rate (DCAR), measured between 2–20 min post contrast administration, as an approximation of IFP. Ge U was measured by serial 19F-MRS for ∼ 1hr post Ge administration. Results: To date 7 pts have been evaluated for the trial. Two pts have entered the trial and completed one cycle of therapy for PK/PD evaluation. Ima produced moderate nausea in both pts. Other toxicity was negligible. In the first pt Ima produced an 18% increase in the ICAR and a 72% increase in the DCAR but there was no significant change observed in the Ge uptake. In the second pt, Ima produced a 60% increase in the ICAR and a 21% increase in the DCAR. Neither of the 2 pts responded to treatment. Further pts are under study and their PK/PD results will be presented. Conclusions: PK and PD can be measured using DCE MRI together with MRS to determine the clinical affects of Ima, Ge, and the Ima-Ge combination. Current results indicate that Ima has a measurable effect on T V, but its relation to drug U and pt response require further pt evaluations to be definitive. [Table: see text]

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Buckling of Shear-Deformable Multi-Layered Rings due to Fluid-Pressure Loading

10.1115/imece2001/ad-23764 ◽

2001 ◽

Author(s):

Jack McNamara ◽

Li Liu ◽

Anthony M. Waas

Keyword(s):

Fluid Pressure ◽

Stacking Sequence ◽

Finite Element Method Analysis ◽

Pressure Loading ◽

Equilibrium Equations ◽

Nonlinear Equilibrium ◽

Method Analysis ◽

Shear Deformable ◽

Theoretical Results ◽

Thickness Shear

Abstract This paper is concerned with the analysis of composite rings subjected to external fluid pressure loading. Nonlinear equilibrium equations, linear stability equations, and critical fluid-pressure loads are found for thin multi-layered shear deformable rings. The extensions presented here can be shown to be generalizations of the theory given in [1]. The theory shows that introduction of multiple layers of material introduces coupling between bending and extension. The results are used to show that shear deformation is important when R h < 10 , as well as when the ratio of through thickness shear modulus to Young’s modulus becomes small. The latter has consequences when composite materials are used for the ring layers. The results are also used to show that for coupling between bending and extension the critical fluid-pressure will increase or decrease depending on the stacking sequence. For the example presented in this paper, the predicted critical fluid-pressure loading was higher for the stiffer material located on the inside of a two-layer ring. In all cases, the theoretical results are compared to a finite element method analysis.

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The socket-shield technique and early implant placement for tooth rehabilitation: A case report

Journal of Clinical Images and Medical Case Reports ◽

10.52768/2766-7820/1118 ◽

2021 ◽

Vol 1 (3) ◽

Author(s):

Getúlio Batista de Oliveira ◽

◽

Mariana de Almeida Basilio ◽

Nara Santos Araujo ◽

Patricia Ramos Cury ◽

...

Keyword(s):

Case Report ◽

Bone Loss ◽

Tooth Extraction ◽

Alveolar Bone ◽

Non Invasive ◽

Implant Placement ◽

Long Time ◽

Bone Preservation ◽

The Aesthetic

For a long time, different approaches to minimize the dimensional ridge alteration following tooth extraction have been described even though none of them was capable to avoid alveolar bone loss. The Socket-Shield Technique (SST) seems to be an alternative for alveolar bone preservation in dental extraction planning. This technique conventionally uses a flapless approach and the buccal root portion retention to prevent bone loss. This case report describes the SST with an early implant placement in a patient who presented the nonrestorable tooth # 15 due to the extensive cavity. After six months of the implant placement a porcelain-fused-to-metal crown was fabricated and screwed into the implant with a satisfactory esthetic and functional result. The SST is a non-invasive and effective approach to tooth extraction and rehabilitation, especially in the aesthetic zone. Approximately two-year follow-up shows a satisfactory aesthetic maintenance.

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