76 FR 57019 - Ball Bearings and Parts Thereof From France, Germany and Italy: Final Results of Sunset Reviews...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-15

... with integral shafts, ball bearings (including radial ball bearings) and parts thereof, and housed or... thereof (inner race, outer race, cage, rollers, balls, seals, shields, etc.) outlined above with certain...

Effect of cage design on characteristics of high-speed-jet-lubricated 35-millimeter-bore ball bearing. [turbojet engines

NASA Technical Reports Server (NTRS)

Schuller, F. T.; Pinel, S. I.; Signer, H. R.

1980-01-01

Parametric tests were conducted with a 35 mm bore angular contact ball bearing with a double outer land guided cage. Provisions were made for jet lubrication and outer-ring cooling of the bearing. Test conditions included a combined thrust and radial load at nominal shaft speeds of 48,000 rpm, and an oil-in temperature of 394 K (250 F). Successful operation of the test bearing was accomplished up to 2.5 million DN. Test results were compared with those obtained with similar bearing having a single outer land guided cage. Higher temperatures were generated with the double outer land guided cage bearing, and bearing power loss and cage slip were greater. Cooling the outer ring resulted in a decrease in overall bearing operating temperature.

Corrosion-Resistant Ball Bearings

NASA Technical Reports Server (NTRS)

Zdankiewicz, E. M.; Linaburg, E. L.; Lytle, L. J.

1990-01-01

Self-lubricating bearing system withstands highly corrosive environment of wastewater-recycling unit. New bearings contain cobalt-based-alloy balls and races, graphite/polyimide polymer ball cages, and single integral polytetrafluoroethylene seals on wet sides. Materials and design prevent corrosion by acids and provide lubrication.

Management of long span partially edentulous maxilla with fixed removable denture prosthesis

PubMed Central

Jeyavalan, Mahilan I.; Narasimman, M.; Venkatakrishnan, C. J.; Philip, Jacob M.

2012-01-01

Restoration of a long span partially edentulous maxilla with tooth supported prosthesis is challenging because of inherent anatomic limitations and unfavourable biomechanics present after the loss of teeth. A tooth supported fixed-removable prosthesis is a treatment option for restoration of such long span partially edentulous maxillary arches. This prosthesis meets the requirements for esthetics, phonetics, comfort, and hygiene, as well as favourable biomechanical stress distribution to the remaining natural tooth abutments. This article presents a procedure for fabrication of a fixed-removable prosthesis that has cement-retained custom cast bar metal substructure and a ball attachment retained removable superstructure prosthesis. PMID:23293488

Management of long span partially edentulous maxilla with fixed removable denture prosthesis.

PubMed

Jeyavalan, Mahilan I; Narasimman, M; Venkatakrishnan, C J; Philip, Jacob M

2012-07-01

Restoration of a long span partially edentulous maxilla with tooth supported prosthesis is challenging because of inherent anatomic limitations and unfavourable biomechanics present after the loss of teeth. A tooth supported fixed-removable prosthesis is a treatment option for restoration of such long span partially edentulous maxillary arches. This prosthesis meets the requirements for esthetics, phonetics, comfort, and hygiene, as well as favourable biomechanical stress distribution to the remaining natural tooth abutments. This article presents a procedure for fabrication of a fixed-removable prosthesis that has cement-retained custom cast bar metal substructure and a ball attachment retained removable superstructure prosthesis.

Bar versus ball attachments for implant-supported overdentures in complete edentulism: A systematic review.

PubMed

Anas El-Wegoud, Marwah; Fayyad, Ahmed; Kaddah, Amal; Nabhan, Ashraf

2018-04-01

Implant-supported overdenture is one of the most predictable treatment options used in complete edentulism. However, differences have been reported between bar and ball attachments used to retain overdentures in terms of patient satisfaction and prosthesis retention. The purpose of this study is to compare the effectiveness of bar and ball attachments for conventionally loaded implant-supported overdentures in completely edentulous patients to improve patient satisfaction and prosthesis retention. We conducted the review according to the Cochrane methods and following MECIR standards. We searched Cochrane Oral Health Group Trial register, Cochrane Central Register of Controlled Trials, MEDLINE, and the WHO ICTRP (March 31, 2017). Two review authors assessed trials for inclusion and risk of bias, extracted data, and checked for accuracy. We have expressed results as risk ratio or mean differences, together with their 95% confidence intervals. We included 10 trials (465 participants). After 5 y, one trial reported higher patient satisfaction when bar attachment was used (MD 1.30, 95% CI 0.20-2.40), and reported no difference between both systems in prosthesis retention (MD -0.90, 95% CI -1.90 to 0.10). Two trials reported no implant failures after 1 and 5 y in both attachments. Downgrading of evidence was based on the unclear risk of bias of included studies and the wide CI crossing the line of no effect. There is insufficient evidence to support bar or ball attachment to be used with implant-supported overdentures in completely edentulous patients to improve patient satisfaction and prosthesis retention (PROSPERO 2014:CRD42014014594). © 2017 Wiley Periodicals, Inc.

Lubrication of 35-millimeter-bore ball bearings of several designs to 2.5 million DN

NASA Technical Reports Server (NTRS)

Schuller, F. T.

1983-01-01

Parametric tests were conducted with 35mm bore, angular contact ball bearings with either a single or double outer and guided cage. The bearings were either lubricated by oil jets or employed inner ring lubrication. Outer ring cooling was added in selected tests. Lubricant flow to the bearing ranged from 300 to 1900 cc/min. All bearings were successfully run at speeds to 2.5 million DN. Increasing the lubricant flow decreased bearing ring temperatures but increased bearing power lines. The power loss and race temperatures of a jet lubricated with double outer land guided cage were always higher than those of the single land guided design at similar test conditions. The lowest bearing operating temperatures were achieved when inner ring lubrication and outer ring cooling were combined. It is found that cage slip of a double outer land guided cage is approximately twice that of a single outer land guided cage.

Operating limitations of high speed jet lubricated ball bearings

NASA Technical Reports Server (NTRS)

Zaretsky, E. V.; Signer, H.; Bamberger, E. N.

1975-01-01

A parametric study was performed with 120-mm bore angular-contact ball bearings having a nominal contact angle of 20 degrees. The bearings had either an inner- or an outer-race land riding cage, and lubrication was by recirculating oil jets which had either a single or dual orifice. Thrust load, speed, and lubricant flow rate were varied. Test results were compared with those previously reported and obtained from bearings of the same design which were under-race lubricated but run under the same conditions. Jet lubricated ball bearings were limited to speeds less than 2,500,000 DN, and bearings having inner-race land riding cages produced lower temperatures than bearings with outer-race land riding cages. For a given lubricant flow rate dual orifice jets produced lower bearing temperatures than single orifice jets, but under-race lubrication produced lower bearing temperatures under all conditions of operation with no apparent bearing speed limitation.

Batting cage performance of wood and nonwood youth baseball bats.

PubMed

Crisco, Joseph J; Rainbow, Michael J; Schwartz, Joel B; Wilcox, Bethany J

2014-04-01

The purpose of this study was to examine the batting cage performance of wood and nonwood baseball bats used at the youth level. Three wood and ten nonwood bats were swung by 22 male players (13 to 18 years old) in a batting cage equipped with a 3-dimensional motion capture (300 Hz) system. Batted ball speeds were compared using a one-way ANOVA and bat swing speeds were analyzed as a function of bat moment of inertia by linear regression. Batted ball speeds were significantly faster for three nonwood bat models (P<.001), significantly slower for one nonwood model, and not different for six nonwood bats when compared with wood bats. Bat impact speed significantly (P<.05) decreased with increasing bat moment of inertia for the 13-, 14-, and 15-year-old groups, but not for the other age groups. Ball-bat coefficients of restitution (BBCOR) for all nonwood were greater than for wood, but this factor alone did not correlate with bat performance. Our findings indicate that increases in BBCOR and swing speed were not associated with faster batted ball speeds for the bats studied whose moment of inertia was substantially less than that of a wood bat of similar length.

Wear-resistant ball bearings for space applications. [coated with titanium carbide

NASA Technical Reports Server (NTRS)

Boving, H.; Hintermann, H. E.; Haenni, W.; Bondivenne, E.; Boeto, M.; Conde, M.

1977-01-01

Ball bearings for hostile environments were developed. They consist of normal ball bearing steel parts of which the rings are coated with hard, wear-resistant, chemical vapor deposited (C.V.D) TiC. Experiments in ultrahigh vacuum, using cages of various materials with self-lubricating properties, have shown that such bearings are suitable for space applications.

Comparison of 2 Zero-Profile Implants in the Treatment of Single-Level Cervical Spondylotic Myelopathy: A Preliminary Clinical Study of Cervical Disc Arthroplasty versus Fusion.

PubMed

Shi, Sheng; Zheng, Shuang; Li, Xin-Feng; Yang, Li-Li; Liu, Zu-De; Yuan, Wen

2016-01-01

Cervical disc arthroplasty (CDA) with Discover prosthesis or anterior cervical discectomy and fusion (ACDF) with Zero-P cage has been widely used in the treatment of cervical spondylotic myelopathy (CSM). However, little is known about the comparison of the 2 zero-profile implants in the treatment of single-level CSM. The aim was to compare the clinical outcomes and radiographic parameters of CDA with Discover prosthesis and ACDF with Zero-P cage for the treatment of single-level CSM. A total of 128 consecutive patients who underwent 1-level CDA with Discover prosthesis or ACDF with Zero-P cage for single-level CSM between September 2009 and December 2012 were included in this study. Clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) score and Neck Disability Index (NDI). For radiographic assessment, the overall sagittal alignment (OSA), functional spinal unit (FSU) angle, and range of motion (ROM) at the index and adjacent levels were measured before and after surgery. Additionally, the complications were also recorded. Both treatments significantly improved all clinical parameters (P < 0.05), without statistically relevant differences between the 2 groups. The OSA and FSU angle increased significantly in both groups (P <0.05). Compared with Zero-P group, ROMs at the index levels were well maintained in the Discover group (P < 0.05). However, there were no statistical differences in the ROMs of adjacent levels between the 2 groups (P > 0.05). Besides, no significant differences existed in dysphagia, subsidence, or adjacent disc degeneration between the 2 groups (P > 0.05). However, significant differences occurred in prosthesis migration in CDA group. The results of this study showed that clinical outcomes and radiographic parameters were satisfactory and comparable with the 2 techniques. However, more attention to prosthesis migration of artificial cervical disc should be paid in the postoperative early-term follow-up.

Insidious strut fractures in a DeBakey-Surgitool aortic valve prosthesis.

PubMed

Scott, S M; Sethi, G K; Paulson, D M; Takaro, T

1978-04-01

Recent reports of cage wear occurring in DeBakey-Surgitool aortic valve prostheses prompted us to examine with image intensification all our patients who have had this type of prosthesis implanted. One patient, who was asymptomatic, was discovered to have a prosthesis with two fractured struts. This patient's prosthetic valve was replaced successfully with a stented porcine heterograft prosthesis. Including the valve removed from this patient, 8 DeBakey-Surgitool aortic valves with structural defects have been reported to the manufacturer. In the absence of a catastrophic event, patients with valves having fractured or worn struts may be totally asymptomatic, and routine periodic roentgenographic examination may be the only way of detecting strut wear or fracture.

Measurement of separator contact forces in ball bearings using a derotation prism

NASA Technical Reports Server (NTRS)

Nypan, L. J.

1978-01-01

A derotation prism was used to produce a stationary image of balls deflecting a portion of the separator. Ball to cage contact forces in a 110 mm bearing at speeds to 12,000 rpm were found to be 25 N (five lb) maximum. Inner race land contact force was found to vary up to 20 N (four lb).

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

Evaluation of drilled-ball bearings at DN values to three million. 1: Variable oil flow tests

NASA Technical Reports Server (NTRS)

Holmes, P. W.

1932-01-01

Two 125-mm-bore solid ball bearings and two similar drilled ball bearings were operated at speeds up to 24,000 rpm (3.0 million DN) with a 13,000 newton (3000 lb) thrust load. The oil flow rate was varied from 0.045 to 0.121 kilograms per second (6 to 16 lb/min). The solid ball bearings operated satisfactorily over the entire range of conditions. The drilled ball bearing experienced cage rub with marginal lubrication at 0.045 kilograms per second (6 lb/min). The drilled ball bearing generally ran cooler than the solid ball bearings.

A geometric constraint, the head-to-tail exclusion rule, may be the basis for the isolated-pentagon rule in fullerenes with more than 60 vertices

PubMed Central

Schein, Stan; Friedrich, Tara

2008-01-01

Carbon atoms self-assemble into the famous soccer-ball shaped Buckminsterfullerene (C60), the smallest fullerene cage that obeys the isolated-pentagon rule (IPR). Carbon atoms self-assemble into larger (n > 60 vertices) empty cages as well—but only the few that obey the IPR—and at least 1 small fullerene (n ≤ 60) with adjacent pentagons. Clathrin protein also self-assembles into small fullerene cages with adjacent pentagons, but just a few of those. We asked why carbon atoms and clathrin proteins self-assembled into just those IPR and small cage isomers. In answer, we described a geometric constraint—the head-to-tail exclusion rule—that permits self-assembly of just the following fullerene cages: among the 5,769 possible small cages (n ≤ 60 vertices) with adjacent pentagons, only 15; the soccer ball (n = 60); and among the 216,739 large cages with 60 < n ≤ 84 vertices, only the 50 IPR ones. The last finding was a complete surprise. Here, by showing that the largest permitted fullerene with adjacent pentagons is one with 60 vertices and a ring of interleaved hexagons and pentagon pairs, we prove that for all n > 60, the head-to-tail exclusion rule permits only (and all) fullerene cages and nanotubes that obey the IPR. We therefore suggest that self-assembly that obeys the IPR may be explained by the head-to-tail exclusion rule, a geometric constraint. PMID:19050075

Comparison of retention and stability of implant-retained overdentures based upon implant number and distribution.

PubMed

Scherer, Michael D; McGlumphy, Edwin A; Seghi, Robert R; Campagni, Wayne V

2013-01-01

The purpose of this investigation was to evaluate the effects of number and distribution of implants upon in vitro dislodging forces to a simulated implant-supported overdenture and to examine differences between several different attachment systems. An experiment was undertaken utilizing a model simulating a mandibular edentulous ridge with dental implants in positions on the model approximating tooth positions in the natural dentition. A cobalt-chromium-cast testing framework was used to measure the peak load required to disconnect an attachment. Four different types of commercially available attachments were used in various positions on the model in sequence to evaluate the effects of retention and stability of overdentures based on implant number and distribution: (1) ERA, (2) O-Ring, (3) Locator, and (4) Ball. For each group, 10 measurements were made of peak dislodging forces. Means were calculated and differences among the systems, directions, and groups were identified using a repeated measured analysis of variance (α = .05). The interactions between the attachment system, direction of force, and implant number and distribution were statistically significant. Vertical dislodging forces of the simulated overdenture prosthesis increased with additional widely spaced implants. Oblique dislodging forces of the simulated prosthesis increased with additional widely spaced implants except in the two-implant model with all attachments, and in the four-implant groups with Locator attachments. Anteroposterior dislodging forces of a simulated overdenture prosthesis increased with additional widely spaced implants except in the four-implant groups with Ball and Locator attachments. Ball attachments reported the highest levels of retention and stability followed by Locator, O-Ring, and ERA. Within the limitations of this study, retention and stability of an implant overdenture prosthesis are significantly affected by implant number, implant distribution, and abutment type.

Simulated studies of wear and friction in total hip prosthesis components with various ball sizes and surface finishes

NASA Technical Reports Server (NTRS)

Swikert, M. A.; Johnson, R. L.

1976-01-01

Experiments were conducted on a newly designed total hip joint simulator. The apparatus closely simulates the complex motions and loads of the human hip in normal walking. The wear and friction of presently used appliance configurations and materials were determined. A surface treatment of the metal femoral ball specimens was applied to influence wear. The results of the investigation indicate that wear can be reduced by mechanical treatment of metal femoral ball surfaces. A metallographic examination and surface roughness measurements were made.

[Phonomechanocardiography in the evaluation of the functional status of valvular prosthesis].

PubMed

Esquivel Avila, J; Molina Zapata, B; Martínez Ríos, M A; Flamand, E

1975-01-01

The FMCG in 22 patients with valvular prosthesis is analyzed and its clinical, hemodynamic and surgical correlation are established (11 from the I.N.C. and 11 from the Hospital Infantil I.M.A.N.). The average age of the patients was 15 years old, 18 had a mitral and six aortic valvulopathy, and they all required a valvular replacement. Of the mitral prosthesis, 14 were Starr-Edwards (13 of ball valve and one of disc), three Lillehei-Kaster and one Börck-Shiley. In 5 patients, the FMCG suspected disfunction that was later corroborated by catheterism in three patients and by surgery in all of them. The important differences of the FMCG between the group with good and the one with bad function were: the aparition of a rumble, a decrease in the amplitud of the closing snap, index of closing snap opering snap of less than one, lenghtening of fases PFVP and IVCP, and shortening of IVDRP. In the patients with auricular fibrilation, after long dyastoles; that would represent an adequate atrial emptying; the closing snap was more intense, the PFVP was lennthened the IVDRP was shortened when the prosthesis was not properly functioning. All the aortic prosthesis were ball valve Starr-Edwards type; in one the FMCG suspected disfunction and the patient had a sudden death outside of the Hospital. The significant differences of the FMCG were the decrease in the intensity of the opening snap, with a Hylen index of less than one, lengthening of the PFVP, IVCP and of the expulsive period (EP). The authors conclude that the FMCG is a good method for an early detection of the disfunctions of valvular prosthesis.

Failure analysis of the ball bearings of dental air turbine handpieces.

PubMed

Wei, M; Dyson, J E; Darvell, B W

2013-12-01

The aim of this study was to identify the nature and causes of deterioration and failure in dental handpiece ball bearings and thus provide guidance for clinical handling for service longevity. The bearings of 36 turbine assemblies were dismantled for visual inspection, documented using a digital camera, and examined using scanning electron microscopy, as appropriate. For the metal parts of the ball bearing assembly, defects observed were mainly wear arising from the running load and corrosion. This was in the form of scratches and discoloured circumferential bands on the balls, and dull or worn surfaces extending around the circumference of the raceways. Cage damage including cracking, fracture, surface rubbing and distortion occurred, in varying degrees, in every failed turbine. Dental ball bearing failure modes have been identified. Cumulative effects of damage from corrosion and mechanical factors lead to handpiece deterioration. The cage was found to be very vulnerable to damage, and this may be the key limitation on bearing lifetime. Autoclaving may contribute to that, as it does to corrosion in the absence of adequate lubrication, but this seems to be minor in comparison to the effects of abuse. There is no justification for failing to observe usage and sterilization instructions. © 2013 Australian Dental Association.

Metallurgical Analysis of Ball Bearing Seized During Operation

NASA Astrophysics Data System (ADS)

Jha, Abhay K.; Swathi Kiranmayee, M.; Ramesh Narayanan, P.; Sreekumar, K.; Sinha, P. P.

2012-06-01

440C stainless steel of martensitic grade is being extensively used for bearing application because of its high wear and corrosion resistance. This alloy steel with 1 wt.% C along with 17 wt.% Cr, 1 wt.% Mn and up to 0.75 wt.% Mo has a number of primary carbides, which provide high hardness and good wear resistance. Owing to its unique performance characteristic, this steel finds a number of applications in space program. One such application is bearing used in booster pump assembly of propulsion system. During one of the ground tests of propulsion system, booster pump bearing seized operation after performing its partial intended function. The bearing was removed from the assembly and cut open. The ball and outer caging were analyzed using metallographic techniques and compared with another bearing taken from the fresh stock. Study indicated that ball as well as outer caging experienced exposure to high temperature and resulted in phase transformation. This article highlights the details of investigations carried out.

75 FR 22384 - Ball Bearings and Parts Thereof From France, Germany, Italy, Japan, and the United Kingdom...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-28

... orders cover all the subject bearings and parts thereof (inner race, outer race, cage, rollers, balls... producer, i.e., sales were made at arm's-length prices. See 19 CFR 351.403(c). We excluded from our... arm's-length prices. To test whether these sales were made at arm's-length prices, we compared the...

Wear-resistant ball bearings for space applications

NASA Technical Reports Server (NTRS)

Boving, H.; Hintermann, H. E.; Hanni, W.; Bondivenne, E.; Boeto, M.; Conde, E.

1977-01-01

Ball bearings consisting of steel parts of which the rings are coated with hard, wear resistant, chemical vapor deposited TiC are described. Experiments conducted in ultrahigh vacuum, using cages of various materials with self-lubricating properties, show that such bearings are suitable for space applications. The results of laboratory tests on the ESA Meteosat Radiometer Focalizing mechanism, which contains six coated bearings, are summarized.

Evaluation of bearing configurations using the single bearing tester in liquid nitrogen

NASA Technical Reports Server (NTRS)

Jett, T.; Hall, P.; Thom, R.

1991-01-01

Various bearing configurations were tested using the Marshall Space Flight Center single bearing tester with LN2 as the cryogenic coolant. The baseline was one Rocketdyne phase one high pressure oxidizer turbopump (HPOTP) pump end 45-mm bore bearing. The bearing configurations that were tested included a Salox/M cage configuration, a silicon nitride ball configuration, an elongated cage configuration, and a Bray 601 grease configuration.

Design and Operating Characteristics of High-Speed, Small-Bore, Angular-Contact Ball Bearings

NASA Technical Reports Server (NTRS)

Pinel, Stanley I.; Signer, Hans R.; Zaretsky, Erwin V.

1998-01-01

The computer program SHABERTH was used to analyze 35-mm-bore, angular-contact ball bearings designed and manufactured for high-speed turbomachinery applications. Parametric tests of the bearings were conducted on a high-speed, high-temperature bearing tester and were compared with the computer predictions. Four bearing and cage designs were studied. The bearings were lubricated either by jet lubrication or through the split inner ring with and without outer-ring cooling. The predicted bearing life decreased with increasing speed because of increased operating contact stresses caused by changes in contact angle and centrifugal load. For thrust loads only, the difference in calculated life for the 24 deg. and 30 deg. contact-angle bearings was insignificant. However, for combined loading, the 24 deg. contact-angle bearing gave longer life. For split-inner-ring bearings, optimal operating conditions were obtained with a 24 deg. contact angle and an inner-ring, land-guided cage, using outer-ring cooling in conjunction with low lubricant flow rates. Lower temperature and power losses were obtained with a single-outer-ring, land-guided cage for the 24 deg. contact-angle bearing having a relieved inner ring and partially relieved outer ring. Inner-ring temperatures were independent of lubrication mode and cage design. In comparison with measured values, reasonably good engineering correlation was obtained using the computer program SHABERTH for predicted bearing power loss and for inner- and outer-ring temperatures. The Parker formula for XCAV (used in SHABERTH, a measure of oil volume in the bearing cavity) may need to be refined to reflect bearing lubrication mode, cage design, and location of cage-controlling land.

Design and preliminary biomechanical analysis of artificial cervical joint complex.

PubMed

Jian, Yu; Lan-Tao, Liu; Zhao, Jian-ning; Jian-ning, Zhao

2013-06-01

To design an artificial cervical joint complex (ACJC) prosthesis for non-fusion reconstruction after cervical subtotal corpectomy, and to evaluate the biomechanical stability, preservation of segment movements and influence on adjacent inter-vertebral movements of this prosthesis. The prosthesis was composed of three parts: the upper/lower joint head and the middle artificial vertebrae made of Cobalt-Chromium-Molybdenum (Co-Cr-Mo) alloy and polyethylene with a ball-and-socket joint design resembling the multi-axial movement in normal inter-vertebral spaces. Biomechanical tests of intact spine (control), Orion locking plate system and ACJC prosthesis were performed on formalin-fixed cervical spine specimens from 21 healthy cadavers to compare stability, range of motion (ROM) of the surgical segment and ROM of adjacent inter-vertebral spaces. As for stability of the whole lower cervical spine, there was no significant difference of flexion, extension, lateral bending and torsion between intact spine group and ACJC prosthesis group. As for segment movements, difference in flexion, lateral bending or torsion between ACJC prosthesis group and control group was not statistically significant, while ACJC prosthesis group showed an increase in extension (P < 0.05) compared to that of the control group. In addition, ACJC prosthesis group demonstrated better flexion, extension and lateral bending compared to those of Orion plating system group (P < 0.05). Difference in adjacent inter-vertebral ROM of the ACJC prosthesis group was not statistically significant compared to that of the control group. After cervical subtotal corpectomy, reconstruction with ACJC prosthesis not only obtained instant stability, but also reserved segment motions effectively, without abnormal gain of mobility at adjacent inter-vertebral spaces.

A BAPTA employing rotary transformers, stepper motors and ceramic ball bearings

NASA Technical Reports Server (NTRS)

Auer, W.

1981-01-01

The utilization of rotary transformers as an alternative to slip rings for the power transfer from solar panels to a satellite's main body could be advantageous, especially if an ac bus system is taken into consideration. Different approaches with main emphasis on the electromagnetic design were investigated and showed efficiencies of up to 99% with a 3 kW power capability. A solidly preloaded pair of ball bearings with ceramic balls assures proper transformer air gaps and acceptable torque changes over temperature and temperature gradients. The bearing and power transfer assembly is driven by a direct drive stepper motor with inherent redundancy properties and needs no caging mechanism.

A high-precision instrument for analyzing nonlinear dynamic behavior of bearing cage.

PubMed

Yang, Z; Chen, H; Yu, T; Li, B

2016-08-01

The high-precision ball bearing is fundamental to the performance of complex mechanical systems. As the speed increases, the cage behavior becomes a key factor in influencing the bearing performance, especially life and reliability. This paper develops a high-precision instrument for analyzing nonlinear dynamic behavior of the bearing cage. The trajectory of the rotational center and non-repetitive run-out (NRRO) of the cage are used to evaluate the instability of cage motion. This instrument applied an aerostatic spindle to support and spin test the bearing to decrease the influence of system error. Then, a high-speed camera is used to capture images when the bearing works at high speeds. A 3D trajectory tracking software tema Motion is used to track the spot which marked the cage surface. Finally, by developing the matlab program, a Lissajous' figure was used to evaluate the nonlinear dynamic behavior of the cage with different speeds. The trajectory of rotational center and NRRO of the cage with various speeds are analyzed. The results can be used to predict the initial failure and optimize cage structural parameters. In addition, the repeatability precision of instrument is also validated. In the future, the motorized spindle will be applied to increase testing speed and image processing algorithms will be developed to analyze the trajectory of the cage.

A high-precision instrument for analyzing nonlinear dynamic behavior of bearing cage

NASA Astrophysics Data System (ADS)

Yang, Z.; Chen, H.; Yu, T.; Li, B.

2016-08-01

The high-precision ball bearing is fundamental to the performance of complex mechanical systems. As the speed increases, the cage behavior becomes a key factor in influencing the bearing performance, especially life and reliability. This paper develops a high-precision instrument for analyzing nonlinear dynamic behavior of the bearing cage. The trajectory of the rotational center and non-repetitive run-out (NRRO) of the cage are used to evaluate the instability of cage motion. This instrument applied an aerostatic spindle to support and spin test the bearing to decrease the influence of system error. Then, a high-speed camera is used to capture images when the bearing works at high speeds. A 3D trajectory tracking software tema Motion is used to track the spot which marked the cage surface. Finally, by developing the matlab program, a Lissajous' figure was used to evaluate the nonlinear dynamic behavior of the cage with different speeds. The trajectory of rotational center and NRRO of the cage with various speeds are analyzed. The results can be used to predict the initial failure and optimize cage structural parameters. In addition, the repeatability precision of instrument is also validated. In the future, the motorized spindle will be applied to increase testing speed and image processing algorithms will be developed to analyze the trajectory of the cage.

A high-precision instrument for analyzing nonlinear dynamic behavior of bearing cage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Z., E-mail: zhaohui@nwpu.edu.cn; Yu, T.; Chen, H.

2016-08-15

The high-precision ball bearing is fundamental to the performance of complex mechanical systems. As the speed increases, the cage behavior becomes a key factor in influencing the bearing performance, especially life and reliability. This paper develops a high-precision instrument for analyzing nonlinear dynamic behavior of the bearing cage. The trajectory of the rotational center and non-repetitive run-out (NRRO) of the cage are used to evaluate the instability of cage motion. This instrument applied an aerostatic spindle to support and spin test the bearing to decrease the influence of system error. Then, a high-speed camera is used to capture images whenmore » the bearing works at high speeds. A 3D trajectory tracking software TEMA Motion is used to track the spot which marked the cage surface. Finally, by developing the MATLAB program, a Lissajous’ figure was used to evaluate the nonlinear dynamic behavior of the cage with different speeds. The trajectory of rotational center and NRRO of the cage with various speeds are analyzed. The results can be used to predict the initial failure and optimize cage structural parameters. In addition, the repeatability precision of instrument is also validated. In the future, the motorized spindle will be applied to increase testing speed and image processing algorithms will be developed to analyze the trajectory of the cage.« less

Cortical Photostimulation Technology for Vision Prosthesis

DTIC Science & Technology

2017-05-01

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions...SUPPLEMENTARY NOTES 14. ABSTRACT The overall goal of the project is to evaluate the feasibility of using photochemical stimulation of cortical neurons as the...glutamate, which can directly stimulate cortical neurons. The new caged molecule has an absorption peak in the visible wavelength range, at 458 nm

Research report: User's manual for computer program AT81y003 SHABERTH. Steady state and transient thermal analysis of a shaft bearing system including ball, cylindrical and tapered roller bearings

NASA Technical Reports Server (NTRS)

Hadden, G. B.; Kleckner, R. J.; Ragen, M. A.; Sheynin, L.

1981-01-01

The SHABERTH program is capable of simulating the thermomechanical performance of a load support system consisting of a flexible shaft supported by up to five rolling element bearings. Any combination of ball, cylindrical, and tapered roller bearings can be used to support the shaft. The user can select models in calculating lubricant film thickness and traction forces. The formulation of the cage pocket/rolling element interaction model was revised to improve solution numerical convergence characteristics.

Design and fabrication of prototype system for early warning of impending bearing failure

NASA Technical Reports Server (NTRS)

Broderick, J. J.; Burchill, R. F.; Clark, H. L.

1972-01-01

Ball bearing performance tests run on several identical ball bearings under a variety of load, speed, temperature, and lubrication conditions are reported. Bearing temperature, torque, vibration, noise, strain, cage speed, etc., were monitored to establish those measurements most suitable as indicators of ball bearing health. Tape records were made under steady-state conditions of a variety of speeds and loads. Sample sections were selected for narrowband spectral analysis with a real time analyzer. An artificial flow was created across the inner race surface of one bearing using an acid etch technique to produce the scratch. Tape records obtained before and after established a characteristic frequency response that identifies the presence of the flow. The signals found most useful as indicators of performance degradation were ultrasonic outputs.

Comparative analysis of use of porous orbital implant with mucus membrane graft and dermis fat graft as a primary procedure in reconstruction of severely contracted socket

PubMed Central

Bhattacharjee, Kasturi; Bhattacharjee, Harsha; Kuri, Ganesh; Das, Jayanta Kr; Dey, Debleena

2014-01-01

Purpose: The purpose of our study is to present a surgical technique of primary porous orbital ball implantation with overlying mucus membrane graft (MMG) for reconstruction of severely contracted socket and to evaluate prosthesis retention and motility in comparison to dermis fat graft (DFG). Study Design: Prospective comparative study. Materials and Methods: A total of 24 patients of severe socket contracture (Grade 2-4 Krishna's classification) were subdivided into two groups, 12 patients in each group. In Group I, DFG have been used for reconstruction. In Group II, porous polyethylene implant with MMG has been used as a primary procedure for socket reconstruction. In Group I DFG was carried out in usual procedure. In case of Group II, vascularized scar tissues were separated 360° and were fashioned into four strips. A scleral capped porous polyethylene implant was placed in the intraconal space and four strips of scar tissue were secured to the scleral cap and extended part overlapped the implant to make a twofold barrier between the implant and MMG. Patients were followed-up as per prefixed proforma. Prosthesis motility and retention between the two groups were measured. Results: In Group I, four patients had recurrence of contracture with fall out of prosthesis. In Group II stable reconstruction was achieved in all the patients. In terms of prosthesis motility, maximum in Group I was 39.2% and Group II, was 59.3%. The difference in prosthesis retention (P = 0.001) and motility (P = 0.004) between the two groups was significant. Conclusion: Primary socket reconstruction with porous orbital implant and MMG for severe socket contracture is an effective method in terms of prosthesis motility and prosthesis retention. PMID:24618485

Structural valve deterioration in a starr-edwards mitral caged-disk valve prosthesis.

PubMed

Aoyagi, Shigeaki; Tayama, Kei-Ichiro; Okazaki, Teiji; Shintani, Yusuke; Kono, Michitaka; Wada, Kumiko; Kosuga, Ken-Ichi; Mori, Ryusuke; Tanaka, Hiroyuki

2013-01-01

The durability of the Starr-Edwards (SE) mitral caged-disk valve, model 6520, is not clearly known, and structural valve deterioration in the SE disk valve is very rare. Replacement of the SE mitral disk valve was performed in 7 patients 23-40 years after implantation. Macroscopic examination of the removed disk valves showed no structural abnormalities in 3 patients, in whom the disk valves were removed at <26 years after implantation. Localized disk wear was found at the sites where the disk abutted the struts of the cage, in disk valves excised >36 years after implantation in 4 patients. Disk fracture, a longitudinal split in the disk along its circumference at the site of incorporation of the titanium ring, was detected in the valves removed 36 and 40 years after implantation, respectively, and many cracks were also observed on the outflow aspect of the disk removed 40 years after implantation. Disk fracture and localized disk wear were found in the SE mitral disk valves implanted >36 years previously. The present results suggest that SE mitral caged-disk valves implanted >20 years previously should be carefully followed up, and that those implanted >30 years previously should be electively replaced with modern prosthetic valves

Architecture of clathrin fullerene cages reflects a geometric constraint--the head-to-tail exclusion rule--and a preference for asymmetry.

PubMed

Schein, Stan

2009-03-27

Fullerene cages have n trivalent vertices, 12 pentagonal faces, and (n-20)/2 hexagonal faces. The smallest cage in which all of the pentagons are surrounded by hexagons and thus isolated from each other has 60 vertices and is shaped like a soccer ball. The protein clathrin self-assembles into fullerene cages of a variety of sizes and shapes, including smaller ones with adjacent pentagons as well as larger ones, but the variety is limited. To explain the range of clathrin architecture and how these fullerene cages self-assemble, we proposed a hypothesis, the "head-to-tail exclusion rule" (the "Rule"). Of the 5769 small clathrin cage isomers with n< or =60 vertices and adjacent pentagons, the Rule permits just 15, three identified in 1976 and 12 others. A "weak version" of the Rule permits another 99. Based on cryo-electron tomography, Cheng et al. reported six raw clathrin fullerene cages. One was among the three identified in 1976. Here, (1) we identify the remaining five. (2) Four are new and are among the 12 others permitted by the Rule. (3) One, also new, is among the 99 weak version cages. (4) Of particular note, none of the remaining 5565 excluded cages has been identified. These findings provide powerful experimental confirmation of the Rule and the principle on which it is based. (5) Surprisingly, the newly identified clathrin cages are among the least symmetric of those permitted. (6) By devising a method for counting assembly paths, (7) we show that asymmetric cages can be assembled by larger numbers of paths, thus providing a kinetic explanation for the prevalence of asymmetric cages. (8) Finally, we show that operation during cage growth of the Rule greatly increases the likelihood of producing a closed fullerene cage, specifically one of those permitted, but efficient assembly still appears to require internal remodeling.

FLUID MECHANICS OF ARTIFICIAL HEART VALVES

PubMed Central

Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P

2009-01-01

SUMMARY 1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird’s-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10–15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage. PMID:19220329

Timing of anticoagulant re-initiation following intracerebral hemorrhage in mechanical heart valves: Survey of neurosurgeons and thrombosis experts.

PubMed

AlKherayf, Fahad; Xu, Yan; Westwick, Harrison; Moldovan, Ioana Doina; Wells, Philip S

2017-03-01

While oral anticoagulation (OAC) is universally indicated for patients with mechanical heart valves (MHVs), OAC resumption following anticoagulant-associated intracerebral hemorrhage (ICH) is an area of uncertainty. We sought to determine the practice preferences of North American neurosurgeons and thrombosis experts on optimal timing of OAC re-initiation. A cross-sectional survey was disseminated to North American members of the American Association of Neurological Surgeons and the International Society for Thrombosis and Haemostasis. Demographic factors, as well as a clinical scenario with 14 modifiable clinical risk factors were included in the survey. 504 physicians completed our survey (response rate 34.3%). Majority of participants were affiliated with academic centres, and managed≤10 ICH patients with MHV per year. There was wide distribution in response in optimal timing for OAC resumption following an ICH: 59% and 60% preferred to re-start OAC between 3 and 14 days following the hemorrhagic event (median of 6-7 days). Smaller hemorrhages (<30cm 2 ). CHADS 2 score ≥2, concomitant venous thromboembolism, mitral valve prosthesis, caged-ball valves and multiple valves prompted earlier OAC resumption. Wide variation in the current practice of neurosurgeons and thrombosis specialists exist when they encounter patients with ICH and MHV, though decisions were influenced by patient- and valve-related factors. As our observed variation likely reflects the immense gap in current evidence, prospective randomized trials in this population are therefore urgently needed. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluid mechanics of artificial heart valves.

PubMed

Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P

2009-02-01

1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird's-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10-15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage.

[Biomechanical analysis of different ProDisc-C arthroplasty design parameters after implanted: a numerical sensitivity study based on finite element method].

PubMed

Tang, Qiaohong; Mo, Zhongjun; Yao, Jie; Li, Qi; Du, Chenfei; Wang, Lizhen; Fan, Yubo

2014-12-01

This study was aimed to estimate the effect of different ProDisc-C arthroplasty designs after it was implanted to C5-C6 cervicalspine. Finite element (FE) model of intact C5-C6 segments including the vertebrae and disc was developed and validated. Ball-and-socket artificial disc prosthesis model (ProDisc-C, Synthes) was implanted into the validated FE model and the curvature of the ProDisc-C prosthesis was varied. All models were loaded with compressed force 74 N and the pure moment of 1.8 Nm along flexion-extension and bilateral bending and axial torsion separately. The results indicated that the variation in the curvature of ball and socket configuration would influence the range of motion in flexion/extension, while there were not apparently differences under other conditions of loads. The method increasing the curvature will solve the stress concentration of the polyethylene, but it will also bring adverse outcomes, such as facet joint force increasing and ligament tension increasing. Therefore, the design of artificial discs should be considered comprehensively to reserve the range of motion as well as to avoid the adverse problems, so as not to affect the long-term clinical results.

Biofilm formation and design features of indwelling silicone rubber tracheoesophageal voice prostheses--an electron microscopical study.

PubMed

Leunisse, C; van Weissenbruch, R; Busscher, H J; van der Mei, H C; Dijk, F; Albers, F W

2001-01-01

After total laryngectomy, voice can be restored with a silicone rubber tracheoesophageal voice prosthesis. However, biofilm formation and subsequent deterioration of the silicone material of the prosthesis will limit device life by impairing valve function. To simulate the natural process of biofilm development under dynamic nutrient conditions, a modified Robbins device was used to evaluate the biofilm-related valve dysfunction of the Groningen, Provox2, Blom-Singer indwelling, and VoiceMaster voice prostheses. Obstruction of the semicircular slit-valved Groningen prosthesis leading to increased airway resistance was caused not only by a buildup of deposits on the esophageal flange and valve hat, but also by accumulation of deposits on the semicircular valve seating. The hinged flap valved Provox2 and indwelling Blom-Singer prostheses failed to close sufficiently because of biofilm formation on the valve seating. The esophageal flange of the VoiceMaster prosthesis was affected, but the tripod structure of the ball valve was fully colonized up to the titanium sleeve, which interfered with proper valve opening and closure. These findings on biofilm formation could be used for the further development and modification of critical design features of voice prostheses to facilitate tracheoesophageal speech. Copyright 2001 John Wiley & Sons, Inc.

A study on the noise characteristics of polymer ball bearings under various lubrication conditions

NASA Astrophysics Data System (ADS)

Dinç, S. K.; Temiz, V.; Kamburoǧlu, E.

2013-12-01

Polymer bearings are generally praised by the manufacturers for running silently. However such statements never go beyond qualitative assumptions. Therefore, studying polymer ball bearing noise would have been meaningful solely on the perspective of silent running machinery. On the other hand, the service life of a polymer ball bearing is unpredictable and there's no preventive maintenance practice that provides data regarding the condition of a polymer ball bearing. In this study, we assume that an investigation of their noise characteristics could also reveal clues concerning their performances. The main objective of this study is to determine the noise characteristics of polymer ball bearings lubricated with different lubricant greases of varying viscosity grades through experimental means. Sound pressure level measurements of SKF brand polymer bearings with polypropylene rings, polypropylene cage and glass balls were made with a 1/2 inch microphone in 1/3-octave bands, at frequencies up to 12.5 kHz, under various radial loads and rotational speeds. The bearings were mounted on a shaft driven by an AC motor with stepless speed control, adjustable between 0 - 1400 rpm. The ball bearings were running inside an acoustic chamber designed for the insulation of environmental noise and the noise of the motor at target frequencies. The resulting sound pressure level spectra were evaluated and the effects of the lubrication conditions on the noise of the ball bearing and possible diagnostic insight that could be gained through studying bearing noise characteristics were discussed.

Comparison Between Oil-mist and Oil-jet Lubrication of High-speed, Small-bore, Angular-contact Ball Bearings

NASA Technical Reports Server (NTRS)

Pinel, Stanley I.; Signer, Hans R.; Zaretsky, Erwin V.

2001-01-01

Parametric tests were conducted with an optimized 35-mm-bore-angular-contact ball bearing on a high-speed, high-temperature bearing tester. Results from both air-oil mist lubrication and oil-jet lubrication systems used to lubricate the bearing were compared to speeds of 2.5 x 10(exp 6) DN. The maximum obtainable speed with air-oil mist lubrication is 2.5 x 10(exp 6) DN. Lower bearing temperatures and higher power losses are obtained with oil-jet lubrication than with air-oil mist lubrication. Bearing power loss is a direct function of oil flow to the bearing and independent of oil delivery system. For a given oil-flow rate, bearing temperature and power loss increase with increases in speed. Bearing life is an inverse function of temperature, the difference in temperature between the individual bearing ring components, and the resultant elastohydrodynamic (EHD) film thicknesses. Bearing life is independent of the oil delivery system except as it affects temperature. Cage slip increased with increases in speed. Cage slip as high as 7 percent was measured and was generally higher with air-oil mist lubrication than with oil-jet lubrication.

Fullerenes formation in flames

NASA Technical Reports Server (NTRS)

Howard, Jack B.

1993-01-01

Fullerenes are composed of carbon atoms arranged in approximately spherical or ellipsoidal cages resembling the geodesic domes designed by Buckminster Fuller, after whom the molecules were named. The approximately spherical fullerene, which resembles a soccer ball and contains sixty atoms (C60), is called buckminsterfullerene. The fullerene containing seventy carbon atoms (C70) is approximately ellipsoidal, similar to a rugby ball. Fullerenes were first detected in 1985, in carbon vapor produced by laser evaporation of graphite. The closed shell structure, which has no edge atoms vulnerable to reaction, was proposed to explain the observed high stability of certain carbon clusters relative to that of others at high temperatures and in the presence of an oxidizing gas.

Seedling ecology and restoration of blackbrush (Coleogyne ramosissima) in the Mojave Desert, United States

USGS Publications Warehouse

Jones, Lisa C.; Schwinning, Susanne; Esque, Todd C.

2014-01-01

Increases in fire frequency are disrupting many ecological communities not historically subjected to fire. In the southwestern United States, the blackbrush (Coleogyne ramosissima) community is among the most threatened, often replaced by invasive annual grasses after fire. This long-lived shrub is vulnerable because it recruits sporadically, partially due to mast seeding and the absence of a seed bank. The goal of this study was to evaluate if shrub restoration can be enhanced by identifying and ameliorating recruitment limitations. Specifically, we tested the effect of encapsulating seeds in predation-deterring “seed balls.” We also tested the effects of nurse plants and mammalian exclusion cages on seedling emergence, growth, and survivorship. These experiments were conducted in a full-factorial design across three sites differing in elevation. Over 2 years, 13% of all planted seeds emerged and the effect of seed balls was overwhelmingly negative because of low emergence. Nurse plants had overall positive effects at Low Elevation, but negative effects at Mid- and High Elevation. Emergence and survival were highest in caged plots everywhere, and effect sizes increased with elevation. Interactions between the cage and the nurse plant treatments indicated that nurse plants tended to attract mammalian predators, lowering emergence and seedling survivorship, particularly at higher elevations. Findings conform to the stress-gradient hypothesis in that interactions among seedlings and mature plants shifted from facilitation to competition as environmental stress decreased with increasing elevation, suggesting that they are transferable to ecologically similar communities elsewhere. Knowledge of site-specific recruitment limitations can help minimize ineffective restoration efforts.

Influence of number of dental autoclave treatment cycles on rotational performance of commercially available air-turbine handpieces.

PubMed

Nagai, Masahiro; Takakuda, Kazuo

2006-06-01

The influence of number of autoclave treatment cycles (N) on rotational speed and total indicated run-out of commercially available air-turbine handpieces from five manufacturers was investigated at N=0, 50, 100, 150, 200, 250 and 300 cycles, and the significance in the test results was assessed by Dunnett's multiple comparison test. Some air-turbine handpieces showed the significant differences in rotational speed at N=300 cycles, however, the decreases of the rotational speeds were only 1 to 3.5 percent. Some air-turbine handpieces showed the significant differences in total indicated run-out, however, the respective values were smaller than that at N=0 cycle. Accordingly, it can be considered that the ball bearing in the air-turbine handpieces is not affected significantly by autoclave. To further evaluate rotational performance, this study focused on the rotational vibration of the ball bearing components of the air-turbine, as measured by Fast Fourier Transform (FFT) analysis; the power spectra of frequency of the ball's revolution, frequency of the cage's rotation and frequency of the ball's rotation were comparatively investigated at N=0, 150 and 300 cycles, and the influence of autoclave was evaluated qualitatively. No abnormalities in the ball bearings were recognized.

Evaluation of transfer films of Salox M on 440C for HPOTP bearing cage applications, task 119

NASA Technical Reports Server (NTRS)

Barber, S. A.; Kannel, J. W.; Dufrane, K. F.

1986-01-01

The objective of the task was to evaluate the suitability of a bronze-filled polytetra fluoroethylene (Salox M) as the cage material in Space Shuttle Main Engine (SSME) high pressure oxygen turbo pump (HPOTP) bearings. The role of the cage pocket material will be to provide a transferred lubricating interface at the ball-race contact region. A series of experiments was conducted which involved block-on-ring tests (the block was the polytetrafluoroethylene (PTFE) -filled material and the ring was through-hardened 440C steel) and high speed traction tests of two 440C disks with one disk rubbed with a PTFE block to generate a transfer film. Measurements included post test visual observations of the condition of the 440C, wear rate measurements of the blocks, and traction measurements between the disks. It was observed that both Salox M and glass-filled PTFE (Armalon) transferred PTFE to 440C at cryogenic temperatures. Bronze is also transferred to uncoated 440C from the Salox M. At room temperature no PTFE transfer was observed in the high speed disk tests due to severe frictional heating, although bronze transfer still occurred with the bronze-PTFE Salox M material. Since the bearing will operate at cryogenic temperature, transfer films are very probable. Salox M wore slightly, although probably tolerably, more than glass-filled PTFE against 440C. However, Salox M is clearly less abrasive to 440C than is the glass-filled material. When the surface layer of PTFE is depleted from the glass-filled material, the glass fibers tend to seriously abrade the steel. This problem does not occur with Salox M. The surface roughness studies indicate that smooth balls are quite reasonable for transfer films. No significant difference in wear rates of the candidate cage materials was observed when the 440C surface finish was increased from 0.025 micron to 0.1 micron cla. At higher levels of roughness, the wear rate increased. Two surface coatings (MoS2 and TiN) were tested. The surface coatings tended to reduce the Salox M wear rate and reduce bronze transfer. PTFE transfer at cryogenic temperatures still occurred with the surface coatings. Two cage design concepts are presented utilizing Salox M material. One design involves a metal-reinforced Salox M cage, while the second design uses Salox M inserts in a metal structure.

Evaluation of bearing mounting design and excessive wear phenomena

NASA Technical Reports Server (NTRS)

Kannel, J. W.

1982-01-01

The effect of bearing thermal growth on the effectiveness of the bearing preload springs on the space shuttle main engine high pressure oxygen turbopump (SSME HPTOP) were examined. The SSME HPTOP turbine end bearings, preload spring, and bearing mounting design were evaluated relative to spalling, excessive ball wear, possible thermal problems, and cage delamination. The magnitude of the thermal stresses required to cause high levels of ball wear were calculated. Plots of maximum sheer stress and maximum reversing shear versus the axial load for the 57 mm SSME HPTOP bearing were created. A plot of the bearing thermal growth versus preload spring deflection was generated. It was determined that metallic wear, rather than thermal growth, caused enlargement of the contact zone between ball and races, that high fatigue-inducing shear stresses are generated under increased loads, and that at temperatures between 100 and 150 deg C, the springs bottom out and very high loads are developed in the bearing. Allowance for adequate spring movement after assembly is recommended.

Dry Lubrication of High Temperature Silicon Nitride Rolling Contacts.

DTIC Science & Technology

1980-11-01

comparable to M50 bearing steel [2]. Quality control measures were implemented in the areas of raw material inspection as well as non-destructive evaluation...to oil lubricated bearing steels . Due to the apparent success of graphite at high tem- perature, three vendors were selected that manufacture graph...hybrid bearings ( steel rings and silicon nitride balls) to establish solid lubricant/cage design practices. High temperature bearing tests with silicon

Effect of two inner-ring oil-flow distribution schemes on the operating characteristics of a 35 millimeter bore ball bearing to 2.5 million DN

NASA Technical Reports Server (NTRS)

Schuller, F. T.; Pinel, S. I.; Signer, H. R.

1985-01-01

Parametric tests were conducted with a 35-mm-bore, split-inner-ring ball bearing with a double-inner-land-guided cage. Provisions were made for through-the-inner-ring lubrication. Test condictions were either a thrust load of 667 N (150 lb) or a combined load of 667 N (150 lb) thrust and 222 N (50 lb) radial, shaft speeds from 32000 to 72000 rpm, and an oil-inlet temperature of 394 K (250 deg F). Outer ring cooling was used in some tests. Tests were run with either 50 or 75 percent of the total oil flow distributed to the inner-ring raceway. Successful operation was experienced with both 50% and 75% flow patterns to 2.5 million DN. Cooling the outer ring had little effect on inner-ring temperature; however, the outer-ring temperature decreased as much as 7% at 2.5 million DN. Maximum recorded power loss was 3.1 kW (4.2 hp), and maximum cage slip was 8.7 percent. Both occurred at a shaft speed of 72000 rpm, a lubricant flow rate of 1900 cu/min (0.50 gal/min), a combined load, and no outer-ring cooling.

Therapeutical attitudes in tooth supported overdentures with ball attachements. Case report

PubMed Central

Țâncu, AM; Melescanu Imre, M; Preoteasa, CT; Preoteasa, E

2014-01-01

Tooth supported overdenture with ball attachments has a number of advantages in prosthetics, but presents some difficulties as well, which sometimes make impossible the use of these anchoring systems; these difficulties should be well known. In this regard we present a suggestive case. It is the case of a patient, aged 57, who came for treatment, suffering from subtotal maxillary and mandibular edentulism (present 11 and 21, respectively 33 and 43), previously having an overdenture prosthesis on natural teeth, with special systems – ball attachment type, dissatisfied with the treatment (due to repeated fractures and functional intolerance to dentures). Clinical examination revealed an increase of the vertical dimension of occlusion and reduced prosthetic space at a correct, functional DVO value, aspects that were explaining the patient’s reported complaints. As a therapeutic approach, having into consideration the balance conditions that were favorable for complete dentures and the large ball attachments volume, which did not allow keeping them at a functional DVO at any of the jaws, and the relatively young age of the patient, it was decided to remove the ball attachments and to keep the teeth for a simple overdenture, both to the maxillar and the mandible, over coronary reduced teeth, enough to allow the denture thickness at a functional DVO. Good end result of prosthetics, with stable, functional dentures, which were well tolerated and offered satisfaction to the patient, have led to an increased quality of life. PMID:27057258

Therapeutical attitudes in tooth supported overdentures with ball attachements. Case report.

PubMed

Țâncu, A M; Melescanu Imre, M; Preoteasa, C T; Preoteasa, E

2014-01-01

Tooth supported overdenture with ball attachments has a number of advantages in prosthetics, but presents some difficulties as well, which sometimes make impossible the use of these anchoring systems; these difficulties should be well known. In this regard we present a suggestive case. It is the case of a patient, aged 57, who came for treatment, suffering from subtotal maxillary and mandibular edentulism (present 11 and 21, respectively 33 and 43), previously having an overdenture prosthesis on natural teeth, with special systems - ball attachment type, dissatisfied with the treatment (due to repeated fractures and functional intolerance to dentures). Clinical examination revealed an increase of the vertical dimension of occlusion and reduced prosthetic space at a correct, functional DVO value, aspects that were explaining the patient's reported complaints. As a therapeutic approach, having into consideration the balance conditions that were favorable for complete dentures and the large ball attachments volume, which did not allow keeping them at a functional DVO at any of the jaws, and the relatively young age of the patient, it was decided to remove the ball attachments and to keep the teeth for a simple overdenture, both to the maxillar and the mandible, over coronary reduced teeth, enough to allow the denture thickness at a functional DVO. Good end result of prosthetics, with stable, functional dentures, which were well tolerated and offered satisfaction to the patient, have led to an increased quality of life.

Finger forces in fastball baseball pitching.

PubMed

Kinoshita, Hiroshi; Obata, Satoshi; Nasu, Daiki; Kadota, Koji; Matsuo, Tomoyuki; Fleisig, Glenn S

2017-08-01

Forces imparted by the fingers onto a baseball are the final, critical aspects for pitching, however these forces have not been quantified previously as no biomechanical technology was available. In this study, an instrumented baseball was developed for direct measurement of ball reaction force by individual fingers and used to provide fundamental information on the forces during a fastball pitch. A tri-axial force transducer with a cable having an easily-detachable connector were installed in an official baseball. Data were collected from 11 pitchers who placed the fingertip of their index, middle, ring, or thumb on the transducer, and threw four-seam fastballs to a target cage from a flat mound. For the index and middle fingers, resultant ball reaction force exhibited a bimodal pattern with initial and second peaks at 38-39ms and 6-7ms before ball release, and their amplitudes were around 97N each. The ring finger and thumb produced single-peak forces of approximately 50 and 83N, respectively. Shear forces for the index and middle fingers formed distinct peak at 4-5ms before release, and the peaks summed to 102N; a kinetic source for backspin on the ball. An additional experiment with submaximal pitching effort showed a linear relationship of peak forces with ball velocity. The peak ball reaction force for fastballs exceeded 80% of maximum finger strength measured, suggesting that strengthening of the distal muscles is important both for enhancing performance and for avoiding injuries. Copyright © 2017 Elsevier B.V. All rights reserved.

Study on torsional fretting wear behavior of a ball-on-socket contact configuration simulating an artificial cervical disk.

PubMed

Wang, Song; Wang, Fei; Liao, Zhenhua; Wang, Qingliang; Liu, Yuhong; Liu, Weiqiang

2015-10-01

A ball-on-socket contact configuration was designed to simulate an artificial cervical disk in structure. UHMWPE (ultra high molecular weight polyethylene) hot pressed by powders and Ti6Al4V alloy were selected as the material combination of ball and socket. The socket surface was coated by a ~500 nm C-DLC (carbon ion implantation-diamond like carbon) mixed layer to improve its surface nano hardness and wear resistance. The torsional fretting wear behavior of the ball-on-socket model was tested at different angular displacements under 25% bovine serum lubrication with an axial force of 100 N to obtain more realistic results with that in vivo. The fretting running regimes and wear damage characteristics as well as wear mechanisms for both ball and socket were studied based on 2D (two dimension) optical microscope, SEM (scanning electron microscope) and 3D (three dimension) profiles. With the increase of angular displacement amplitude from 1° to 7°, three types of T-θ (Torsional torque-angular displacement amplitude) curves (i.e., linear, elliptical and parallelogram loops) corresponding to running regimes of PSR (partial slip regime), MR (mixed regime) and SR (slip regime) were observed and analyzed. Both the central region and the edge zone of the ball and socket were damaged. The worn surfaces were characterized by wear scratches and wear debris. In addition, more severe wear damage and more wear debris appeared on the central region of the socket at higher angular displacement amplitude. The dominant damage mechanism was a mix of surface scratch, adhesive wear and abrasive wear for the UHMWPE ball while that for the coated socket was abrasive wear by PE particles and some polishing and rolling process on the raised overgrown DLC grains. The frictional kinetic behavior, wear type, damage region and damage mechanism for the ball-on-socket model revealed significant differences with those of a ball-on-flat contact while showing better consistency with that of in vitro cervical prosthesis simulations according to the literature. Copyright © 2015. Published by Elsevier B.V.

Early failure mechanisms of constrained tripolar acetabular sockets used in revision total hip arthroplasty.

PubMed

Cooke, Christopher C; Hozack, William; Lavernia, Carlos; Sharkey, Peter; Shastri, Shani; Rothman, Richard H

2003-10-01

Fifty-eight patients received an Osteonics constrained acetabular implant for recurrent instability (46), girdlestone reimplant (8), correction of leg lengthening (3), and periprosthetic fracture (1). The constrained liner was inserted into a cementless shell (49), cemented into a pre-existing cementless shell (6), cemented into a cage (2), and cemented directly into the acetabular bone (1). Eight patients (13.8%) required reoperation for failure of the constrained implant. Type I failure (bone-prosthesis interface) occurred in 3 cases. Two cementless shells became loose, and in 1 patient, the constrained liner was cemented into an acetabular cage, which then failed by pivoting laterally about the superior fixation screws. Type II failure (liner locking mechanism) occurred in 2 cases. Type III failure (femoral head locking mechanism) occurred in 3 patients. Seven of the 8 failures occurred in patients with recurrent instability. Constrained liners are an effective method for treatment during revision total hip arthroplasty but should be used in select cases only.

The formation of ReS(2) inorganic fullerene-like structures containing Re(4) parallelogram units and metal-metal bonds.

PubMed

Coleman, Karl S; Sloan, Jeremy; Hanson, Neal A; Brown, Gareth; Clancy, Gerald P; Terrones, Mauricio; Terrones, Humberto; Green, Malcolm L H

2002-10-02

The encapsulation of ReO(x) within ReS(2) inorganic fullerene-like cages is described for the first time. The encapsulate was prepared by the sulfidization of both hand-milled and ball-milled samples of ReO(2); partial conversion of the oxide to the sulfide was achieved with the degree of sulfidization depending on the exposure to the sulfidizing agent, H(2)S.

Design and Use of a 3D Prosthetic Leg in a Red-lored Amazon Parrot ( Amazona autumnalis).

PubMed

Galicia, Cecilia; Hernandez Urraca, Vanessa; Del Castillo, Luis; Mvz, Jaime Samour

2018-06-01

A three-dimensional (3D) prosthesis was designed and built for a red-lored Amazon parrot ( Amazona autumnalis) with a pre-existing amputation of the distal left leg at the tibiotarsal-tarsometatarsal joint and injuries to the right leg caused by cage companion aggression. The prosthesis consisted of a straight main imprint, with a round element at both ends to provide stability, and a bridge connecting this to a socket without a bottom where the stump could be accommodated and held securely with self-adhesive bandaging. Over a 4-month period, 3 different 3D prosthetic models were made and evaluated. The first model was fitted, but the parrot would only use the tip of the main imprint to stand and walk. The second model was designed with a semicircular imprint with only 1 round element at the cranial end, a different bridge to accommodate the change to the main imprint, and the same socket. With these changes, the parrot was able to place the imprint of the prosthesis on the floor to stand and move freely around its enclosure. To accommodate morphologic changes on the stump, a third model was created consisting of the same imprint and bridge, but the socket was cut vertically all the way on one side to allow distention on its diameter and provide a long-lasting fit to the stump over time.

Finite-Difference Solutions of the Alternate Turbopump Development High-Pressure Oxidizer Turbopump Pump-End Ball-Bearing Cavity Flows

NASA Technical Reports Server (NTRS)

Benjamin, Theodore G.; Garcia, Roberto; Mcconnaughey, Paul K.; Wang, Ten-See; Vu, Bruce T.; Dakhoul, Youssef

1993-01-01

These analyses were undertaken to aid in the understanding of flow phenomena in the Alternate Turbopump Development (ATD) High-pressure Oxidizer Turbopump (HPOTP) Pump-end ball bearing (PEBB) cavities and their roles in turbopump vibration initiation and bearing distress. This effort was being performed to provide timely support to the program in a decision as to whether or not the program should be continued. In the first case, it was determined that a change in bearing through flow had no significant effect on axial preload. This was a follow-on to a previous study which had resulted in a redesign of the bearing exit cavity which virtually eliminated bearing axial loading. In the second case, a three-dimensional analysis of the inner-race-guided cage configuration was performed so as to determine the pressure distribution on the outer race when the shaft is 0.0002 inches off-center. The results indicate that there is virtually no circumferential pressure difference caused by the offset to contribute to bearing tilt. In the third case, axisymmetric analyses were performed on an outer-race guided cage configuration to determine the magnitude of tangential flow entering the bearing. The removed-shoulder case was analyzed as was the static diverter case. A third analysis where the preload spring was shielded by a sheet of metal for the baseline case was also performed. It was determined that the swirl entering the bearing was acceptable and the project decided to use the outer-race-guided cage configuration. In the fourth case, more bearing configurations were analyzed. These analyses included thermal modeling so as to determine the added benefit of injecting colder fluid directly onto the bearing inner-race contact area. The results of these analyses contributed to a programmatic decision to include coolant injection in the design.

Spherical, rolling magnet generators for passive energy harvesting from human motion

NASA Astrophysics Data System (ADS)

Bowers, Benjamin J.; Arnold, David P.

2009-09-01

In this work, non-resonant, vibrational energy harvester architectures intended for human-motion energy scavenging are researched. The basic design employs a spherical, unidirectionally magnetized permanent magnet (NdFeB) ball that is allowed to move arbitrarily in a spherical cavity wrapped with copper coil windings. As the ball rotates and translates within the cage, the time-varying magnetic flux induces a voltage in the coil according to Faraday's Law. Devices ranging from 1.5 cm3 to 4 cm3 in size were tested under human activity scenarios—held in the user's hand or placed in the user's pocket while walking (4 km h-1) and running (14.5 km h-1). These harvesters have demonstrated rms voltages ranging from ~80 mV to 700 mV and time-averaged power densities up to 0.5 mW cm-3.

The M6-C Cervical Disk Prosthesis: First Clinical Experience in 33 Patients.

PubMed

Thomas, Sam; Willems, Karel; Van den Daelen, Luc; Linden, Patrick; Ciocci, Maria-Cristina; Bocher, Philippe

2016-05-01

Retrospective study. To determine the short-term clinical succesrate of the M6-C cervical disk prosthesis in primary and secondary surgery. Cervical disk arthroplasty (CDA) provides an alternative to anterior cervical decompression and fusion for the treatment of spondylotic radiculopathy or myelopathy. The prevention of adjacent segment disease (ASD), a possible complication of anterior cervical decompression and fusion, is its most cited--although unproven--benefit. Unlike older arthroplasty devices that rely on a ball-and-socket-type design, the M6-C cervical disk prosthesis represents a new generation of unconstrained implants, developed to achieve better restoration of natural segmental biomechanics. This device should therefore optimize clinical performance of CDA and reduce ASD. All patients had preoperative computed tomography or magnetic resonance imaging and postoperative x-rays. Clinical outcome was assessed using the Neck Disability Index, a Visual Analog Scale, and the SF-36 questionnaire. Patients were asked about overall satisfaction and whether they would have the surgery again. Thirty-three patients were evaluated 17.1 months after surgery, on average. Nine patients had a history of cervical interventions. Results for Neck Disability Index, Visual Analog Scale, and SF-36 were significantly better among patients who had undergone primary surgery. In this group, 87.5% of patients reported a good or excellent result and 91.7% would have the procedure again. In contrast, all 4 device-related complications occurred in the small group of patients who had secondary surgery. The M6-C prosthesis appears to be a valuable addition to the CDA armatorium. It generates very good results in patients undergoing primary surgery, although its use in secondary surgery should be avoided. Longer follow-up is needed to determine to what measure this device can prevent ASD.

Multi-dimensional printing in thoracic surgery: current and future applications

PubMed Central

Kwok, Jackson K. S.; Lau, Rainbow W. H.; Zhao, Ze-Rui; Yu, Peter S. Y.; Ho, Jacky Y. K.; Chow, Simon C. Y.; Wan, Innes Y. P.

2018-01-01

Three-dimensional (3D) printing has been gaining much attention in the medical field in recent years. At present, 3D printing most commonly contributes in pre-operative surgical planning of complicated surgery. It is also utilized for producing personalized prosthesis, well demonstrated by the customized rib cage, vertebral body models and customized airway splints. With on-going research and development, it will likely play an increasingly important role across the surgical fields. This article reviews current application of 3D printing in thoracic surgery and also provides a brief overview on the extended and updated use of 3D printing in bioprinting and 4D printing. PMID:29732197

Bearing tester data compilation analysis, and reporting and bearing math modeling

NASA Technical Reports Server (NTRS)

Cody, J. C.

1986-01-01

Integration of heat transfer coefficients, modified to account for local vapor quality, into the 45 mm bearing model has been completed. The model has been evaluated with two flow rates and subcooled and saturated coolant. The evaluation showed that by increasing the flow from 3.6 to 7.0 lbs/sec the average ball temperature was decreased by 102 F, using a coolant temperature of -230 F. The average ball temperature was decreased by 63 F by decreasing the inlet coolant temperature from saturated to -230 F at a flow rate of 7.0 lbs/sec. Since other factors such as friction, cage heating, etc., affect bearing temperatures, the above bearing temperature effects should be considered as trends and not absolute values. The two phase heat transfer modification has been installed in the 57 mm bearing model and the effects on bearing temperatures have been evaluated. The average ball temperature was decreased by 60 F by increasing the flow rate from 4.6 to 9.0 lbs/sec for the subcooled case. By decreasing the inlet coolant temperature from saturation to -24 F, the average ball temperature was decreased 57 F for a flow rate of 9.0 lbs/sec. The technique of relating the two phase heat transfer coefficient to local vapor quality will be applied to the tester model and compared with test data.

[Revision hip arthroplasty by Waldemar Link custom-made total hip prosthesis].

PubMed

Medenica, Ivica; Luković, Milan; Radoicić, Dragan

2010-02-01

The number of patients undergoing hip arthroplasty revision is constantly growing. Especially, complex problem is extensive loss of bone stock and pelvic discontinuity that requires reconstruction. The paper presented a 50-year old patient, who ten years ago underwent a total cement artrhroplasty of the left hip. A year after the primary operation the patient had difficulties in walking without crutches. Problems intensified in the last five years, the patient had severe pain, totally limited movement in the left hip and could not walk at all. Radiographically, we found loose femoral component, massive loss of bone stock of proximal femur, acetabular protrusion and a consequent pelvic discontinuity. Clinically, a completely disfunctional left hip joint was registered (Harris hip score--7.1). We performed total rearthroplasty by a custom-made Waldemar Link total hip prosthesis with acetabular antiprotrusio cage and compensation of bone defects with a graft from the bone bank. A year after the operation, we found clinically an extreme improvement in Harris hip score--87.8. Radiographically, we found stability of implanted components, a complete graft integration and bone bridging across the site of pelvic discontinuity. Pelvic discontinuity and massive loss of proximal femoral bone stock is a challenging and complex entity. Conventional prostheses cannot provide an adequate fixation and stability of the hip. Application of custom-made prosthesis (measured specificaly for a patient) and additional alografting bone defects is a good method in revision surgery after unsuccessful hip arthroplasty with extensive bone defects.

A Qualitative Study on Patients' Perceptions of Two Types of Attachments for Implant Overdentures.

PubMed

Pisani, Marina; Bedos, Christophe; da Silva, Cláudia Helena Lovato; Fromentin, Olivier; de Albuquerque, Rubens F

2017-12-01

The aim of this qualitative study was to gain a deeper understanding of patient perceptions of wearing implant-retained overdentures with ball-shaped or cylindrical attachment systems. Twenty-two wearers of implant-supported overdentures participated in this qualitative study based on a randomized crossover clinical trial that aimed to compare a cylindrical attachment and a ball attachment. In phase I of the study, group A experienced ball attachments (n = 11) and group B Locator attachments (n = 11) for 1 year. Afterward, in phase II, the attachments were changed; group A received Locator attachments and group B received ball attachments. One week after the attachment's replacement, semistructured individual interviews were conducted. All interviews were audiotaped and transcribed. The analysis was guided by thematic content analysis. Most of the patients from both groups preferred the attachment they received in phase II, regardless the type. A major theme raised by the participants to justify their preference between the attachment types was prosthesis retention/stability, sometimes considered as a positive and other times as a negative factor. Other themes were also explored: oral function, pain, hygiene, previous experiences, confidence on the dentist's work, and esthetic. Aspects related to the retention/stability of the overdentures are the main concerns associated with the perceptions of most patients treated with implant overdentures regardless of the type of attachment. Adequate retention level should be identified and adjusted on an individual basis and maintained overtime as possible. Therefore, follow-up appointments should be planned for readjustment of the attachment's retention. Overretention should be avoided.

ENUCLEATION IN MALIGNANT CHOROIDAL MELANOMA - results in 15 years of using a new material in the prosthesis of the orbital cavity

PubMed Central

Tataru, CP; Pop, MD

2012-01-01

Rationale: Enucleation implants are covered with a material that allows the fixation of the extraocular rectus muscles. Usually, the implants are covered in donor sclera, which implies the risk of infection transmission, inflammation and implant rejection, being also an expensive procedure. The new materials used for implant meshing should be tested and a safer and cost effective solution should be researched. Objective: This study presents the results obtained after a 15-year use of an original prosthesis for the reconstruction of the orbital cavity after enucleation surgery. Methods and results: 42 eyes of 42 patients who underwent enucleation surgery for choroidal malignant melanoma were included in the study. The surgical technique was very similar to the classic enucleation, the major difference being the implant of a prosthesis made out of a Polymethyl methacrylate (PMMA) ball covered by a Polyethylene terephthalate (dacron) shell used in cardiovascular surgery. All the patients had a very good technical result, without the inflammation of the orbital cavity, conjunctiva or eyelids, which demonstrates a very high material tolerability and an excellent cosmetic result. Late implant expulsion appeared in 7.14% of the patients (3 cases). Discussion: The particularly good results obtained by using this technique, the absence of an inflammatory reaction after surgery, and the long lasting stability of the implant, recommend the method as being safe, with no major complications and a good esthetic result. AbbreviationsPolymethyl methacrylate (PMMA), Malignant choroidal melanoma (CMM) PMID:22802888

Fabrication and characterization of DLC coated microdimples on hip prosthesis heads.

PubMed

Choudhury, Dipankar; Ay Ching, Hee; Mamat, Azuddin Bin; Cizek, Jan; Abu Osman, Noor Azuan; Vrbka, Martin; Hartl, Martin; Krupka, Ivan

2015-07-01

Diamond like carbon (DLC) is applied as a thin film onto substrates to obtain desired surface properties such as increased hardness and corrosion resistance, and decreased friction and wear rate. Microdimple is an advanced surface modification technique enhancing the tribological performance. In this study, DLC coated microdimples were fabricated on hip prosthesis heads and their mechanical, material and surface properties were characterized. An Electro discharge machining (EDM) oriented microdrilling was utilized to fabricate a defined microdimple array (diameter of 300 µm, depth of 70 µm, and pitch of 900 µm) on stainless steel (SS) hip prosthesis heads. The dimpled surfaces were then coated by hydrogenated amorphous carbon (a-C:H) and tetrahedral amorphous carbon (Ta-C) layers by using a magnetron sputtering technology. A preliminary tribology test was conducted on these fabricated surfaces against a ceramic ball in simulated hip joint conditions. It was found that the fabricated dimples were perpendicular to the spherical surfaces and no cutting-tools wear debris was detected inside the individual dimples. The a-C:H and Ta-C coatings increased the hardness at both the dimple edges and the nondimpled region. The tribology test showed a significant reduction in friction coefficient for coated surfaces regardless of microdimple arrays: the lowest friction coefficient was found for the a-C:H samples (µ = 0.084), followed by Ta-C (µ = 0.119), as compared to the SS surface (µ = 0.248). © 2014 Wiley Periodicals, Inc.

Synthesis and evaluation of C-ether formulations for use as high temperature lubricants and hydraulic fluids

NASA Technical Reports Server (NTRS)

Clark, F. S.; Green, R. L.; Miller, D. R.

1974-01-01

The formulation and evaluation of C-ether fluids for use in the hydraulic and lubrication systems of the space shuttle and advanced air breathing engines were studied to lower the pour point of a reference C-ether from -29 C to -40 C without changing its evaporation loss. Use of disiloxanes mixed with C-ethers gave a -40 C pour point fluid with little change in the desired evaporation loss or in oxidative stability. A second -40 C pour point fluid containing only C-ethers was also developed. A screening program tested lubrication additives for C-ethers and the new fluids. Six additive packages were chosen for evaluation in 316 C bearing tests, two for evaluation in 260 C pump tests. The goal of the bearing test was a 100 hour run. The rig was a specially designed 80-mm axially loaded ball bearing. The C-ether base fluid ran only one hour at 316 C before cage wear failure occurred. The best additive blends ran 47, 94 and 100 hours. The 96 hour test gave excessive deposits. The 100 hour test had no wear failures; an unexplained loss of cage silver occurred from areas of direct fluid impingement on the cage.

The Ball Welding Bar: A New Solution for the Immediate Loading of Screw-Retained, Mandibular Fixed Full Arch Prostheses

PubMed Central

Bacchiocchi, Danilo

2017-01-01

Purpose To present a new intraoral welding technique, which can be used to manufacture screw-retained, mandibular fixed full-arch prostheses. Methods Over a 4-year period, all patients with complete mandibular edentulism or irreparably compromised mandibular dentition, who will restore the masticatory function with a fixed mandibular prosthesis, were considered for inclusion in this study. The “Ball Welding Bar” (BWB) technique is characterised by smooth prosthetic cylinders, interconnected by means of titanium bars which are adjustable in terms of distance from ball terminals and are inserted in the rotating rings of the cylinders. All the components are welded and self-posing. Results Forty-two patients (18 males; 24 females; mean age 64.2 ± 6.7 years) were enrolled and 210 fixtures were inserted to support 42 mandibular screw-retained, fixed full-arch prostheses. After two years of loading, 2 fixtures were lost, for an implant survival rate of 97.7%. Five implants suffered from peri-implant mucositis and 3 implants for peri-implantitis. Three of the prostheses (3/42) required repair for fracture (7.1%): the prosthetic success was 92.9%. Conclusions The BWB technique seems to represent a reliable technique for the fabrication of screw-retained mandibular fixed full-arch prostheses. This study was registered in the ISRCTN register with number ISRCTN71229338. PMID:28835752

The first stable lower fullerene: C{sub 36}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piskoti, C.; Zettl, A.

1998-08-01

A new pure carbon material, presumably composed of thirty six carbon atom molecules, has been synthesized and isolated in milligram quantities. It appears as though these molecules have a closed cage structure making them the smallest member of a new class of molecules known as fullerenes, most notably of which is the soccer ball shaped C{sub 60}. However, unlike other known fullerenes, any closed, fullerene-like C{sub 36} cage will necessarily contain fused pentagon rings. Therefore, this molecule apparently violates the isolated pentagon rule, a criterion which requires isolated pentagons for stability in fullerene molecules. Striking parallels between this problem andmore » the synthesis of other fused five member fused ring systems will be discussed. Also, it will be shown that certain biological structures known as clathrin behave in a manner which gives excellent predictions about fullerenes and nanotubes. These predictions help to explain the presence of abundant quantities of C{sub 36} in arced graphite soot. {copyright} {ital 1998 American Institute of Physics.}« less

SSME turbopump bearing analytical study

NASA Technical Reports Server (NTRS)

Kannel, J. W.; Merriman, T.

1980-01-01

Three shuttle pump bearings operating under severe overspeed and shut-down conditions are evaluated. The specific parameters investigated include outer race stresses, cage stresses, cage-race drag, bearing heating, and crush loading. A quasi-dynamic version of the BASDAP computer code was utilized which involved the calculation of ball-race forces (inner and outer), contact pressures, contact dimensions, and contact angles as a function of (1) axial load, (2) radial load, and (3) centrifugal load on the bearing. Generally, radial loads on the order of 13,300 N (3000 pounds) per bearing or 26,700 N (6000 pounds) per bearing pair, could be expected to cause severe problems to any of the bearings with a 17,800 N (4000 pounds) axial load. Further, when possible temperature excursions are considered, even a load of 8900 N (2000 pounds) may be excessive. However, high momentary radial loads with a 3800 N (850 pounds) axial load would not be anticipated to cause catastrophic failure of the fuel pump bearing.

Operating characteristics of 120-millimeter-bore ball bearings at 3 million DN

NASA Technical Reports Server (NTRS)

Zaretsky, E. V.; Bamberger, E. N.; Signer, H.

1974-01-01

A parametric study was performed with split inner-race 120-mm-bore angular-contact ball bearings at a speed of 25,000 rpm (3 million DN) at initial contact angles of 20 deg and 24 deg. Provisions were made for outer- and inner-race cooling and for injection of lubricant into the bearing through a number of radial holes in the split inner-race of the bearing. Oil flow and coolant rate to the bearing was controlled and varied for a total up to approximately 3.2 gal/min. Bearing temperature was found to decrease as the total lubricant flow to the bearing increased. However, at intermediate flow rates temperature began to increase with increasing flow. Power consumption increased with increasing flow rate. Bearing operating temperature, differences in temperatures between the inner and outer races, and bearing power consumption can be tuned to any desirable operating requirement. Cage speed increased by not more than 2 percent with increasing oil flow to the inner race.

Experimental measurement of flexion-extension movement in normal and corpse prosthetic elbow joint.

PubMed

TarniŢă, Daniela; TarniŢă, DănuŢ Nicolae

2016-01-01

This paper presents a comparative experimental study of flexion-extension movement in healthy elbow and in the prosthetic elbow joint fixed on an original experimental bench. Measurements were carried out in order to validate the functional morphology and a new elbow prosthesis type ball head. The three-dimensional (3D) model and the physical prototype of our experimental bench used to test elbow endoprosthesis at flexion-extension and pronation-supination movements is presented. The measurements were carried out on a group of nine healthy subjects and on the prosthetic corpse elbow, the experimental data being obtained for flexion-extension movement cycles. Experimental data for the two different flexion-extension tests for the nine subjects and for the corpse prosthetic elbow were acquired using SimiMotion video system. Experimental data were processed statistically. The corresponding graphs were obtained for all subjects in the experimental group, and for corpse prosthetic elbow for both flexion-extension tests. The statistical analysis has proved that the flexion angles of healthy elbows were significantly close to the values measured at the prosthetic elbow fixed on the experimental bench. The studied elbow prosthesis manages to re-establish the mobility for the elbow joint as close to the normal one.

Implant Failure After Motec Wrist Joint Prosthesis Due to Failure of Ball and Socket-Type Articulation-Two Patients With Adverse Reaction to Metal Debris and Polyether Ether Ketone.

PubMed

Karjalainen, Teemu; Pamilo, Konsta; Reito, Aleksi

2018-04-21

We describe 2 cases of articulation-related failures resulting in revision surgery after a Motec total wrist arthroplasty: one with an adverse reaction to metal debris and the other with an adverse reaction to polyether ether ketone. In the first patient, blood cobalt and chrome levels were elevated and magnetic resonance imaging showed clear signs of a pseudotumor. The other patient had an extensive release of polyether ether ketone particles into the surrounding synovia due to adverse wear conditions in the cup, leading to the formation of a fluid-filled cyst sac with a black lining and diffuse lymphocyte-dominated inflammation in the synovia. We recommend regular follow-up including x-rays, monitoring of cobalt and chrome ion levels, and a low threshold for cross-sectional imaging in patients who have undergone total wrist arthroplasty with a Motec joint prosthesis. Wear-related problems can also develop in implants in which polyether ether ketone is the bulk material. Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Cu2O-directed in situ growth of Au nanoparticles inside HKUST-1 nanocages.

PubMed

Liu, Yongxin; Liu, Ting; Tian, Long; Zhang, Linlin; Yao, Lili; Tan, Taixing; Xu, Jin; Han, Xiaohui; Liu, Dan; Wang, Cheng

2016-12-07

Controllable integration of metal nanoparticles (MNPs) and metal-organic frameworks (MOFs) is attracting considerable attention as the obtained composite materials always show synergistic effects in applications of catalysis, delivery, as well as sensing. Herein, a Cu 2 O-directed in situ growth strategy was developed to integrate Au nanoparticles and HKUST-1. In this strategy, Cu 2 O@HKUST-1 core-shell heterostructures, HKUST-1 nanocages, Cu 2 O@Au@HKUST-1 sandwich core-shell heterostructures and Au@HKUST-1 balls-in-cage heterostructures were successfully synthesized. Cu 2 O@HKUST-1 core-shell heterostructures were synthesized by soaking Cu 2 O nanocrystals in benzene-1,3,5-tricarboxylic acid solution. The well-defined Cu 2 O@HKUST-1 core-shell heterostructures were demonstrated to be dominated by the ratio of Cu 2+ cations to btc 3- ligands in solution during the period of HKUST-1 formation. Cu 2 O@Au@HKUST-1 sandwich core-shell or Au@HKUST-1 balls-in-cage heterostructures were obtained by impregnating HAuCl 4 into Cu 2 O@HKUST-1 core-shell heterostructures. Due to the porosity of HKUST-1 and reducibility of Cu 2 O, HAuCl 4 could pass through the HKUST-1 shell and be reduced by the Cu 2 O core in situ forming Au nanoparticles. Finally, CO oxidation reaction at high temperatures was carried out to assess the catalytic functionality of the obtained composite heterostructures. This strategy can circumvent some drawbacks of the existing approaches for integrating MNPs and MOFs, such as nonselective deposition of MNPs at the outer surface of the MOF matrices, extreme treatment conditions and additional surface modifications.

Behavior tests and immunohistochemical retinal response analyses in RCS rats with subretinal implantation of Okayama-University-type retinal prosthesis.

PubMed

Alamusi; Matsuo, Toshihiko; Hosoya, Osamu; Tsutsui, Kimiko M; Uchida, Tetsuya

2013-09-01

We have developed a photoelectric dye-coupled polyethylene film as a prototype of retinal prosthesis, which we named Okayama University-type retinal prosthesis. The purposes of this study are to conduct behavior tests to assess vision in Royal College of Surgeons (RCS) rats that underwent subretinal implantation of the dye-coupled film and to reveal retinal response to the dye-coupled film by immunohistochemistry. Polyethylene films were made of polyethylene powder at refined purity, and photoelectric dyes were coupled to the film surface at higher density compared with the prototype. Either dye-coupled film or dye-uncoupled plain film used as a control was implanted subretinally from a scleral incision in both eyes of an RCS rat at 6 weeks of the age. Behavior tests 2, 4, 6, and 8 weeks after implantation were conducted by observing head turning or body turning in the direction consistent with clockwise or counterclockwise rotation of a black-and-white-striped drum around a transparent cage housed with the rat. After the behavior tests at 8 weeks, rats' eyes were enucleated to confirm subretinal implantation of the films and processed for immunohistochemistry. In the behavior tests, the number of head turnings consistent with the direction of the drum rotation was significantly larger in RCS rats with dye-coupled- compared with plain-film implantation [P < 0.05, repeated-measure analysis of variance (ANOVA), n = 7]. The number of apoptotic neurons was significantly smaller in eyes with dye-coupled- compared with plain-film implantation (P < 0.05, Mann-Whitney U test, n = 6). In conclusion, subretinal implantation of photoelectric dye-coupled films restored vision in RCS rats and prevented the remaining retinal neurons from apoptosis.

GIOTTO's antenna de-spin mechanism: Ots lubrication and thermal vacuum performance

NASA Technical Reports Server (NTRS)

Todd, M. J.; Parker, K.

1987-01-01

Except in the near Earth phase of GIOTTO's mission to Comet Halley, the HGA (high gain antenna) on board GIOTTO was the only designed means of up/down communications. The spacecraft spin stabilization required that the HGA be despun at the same rotational rate of nominally 15 rpm in order to keep the HGA pointing accurately to a Earth. A dual servomotor despin mechanism was designed and built by SEP of France for this purpose. The expected thermal environment suggested that dry lubrication was preferable to wet for the ball bearings but there existed no relevant data on the torque noise spectrum of candidate solid lubricants. Therefore ad hoc torque noise tests were run with two solid lubricants: ion plated lead film plus lead bronze cage (retainer) and a PTFE composite cage only. The lead lubrication showed the better spectrum up to the mission lifetime point so it was selected for continued test over some 20 times the Halley mission life, with periodic torque spectrum monitoring. The spectrum remained well within the pointing error budget over the 100 million revolutions covered.

30 years of cosmic fullerenes

NASA Astrophysics Data System (ADS)

Berné, O.; Montillaud, J.; Mulas, G.; Joblin, C.

2015-12-01

In 1985, ``During experiments aimed at understanding the mechanisms by which long-chain carbon molecules are formed in interstellar space and circumstellar shells'', Harry Kroto and his collaborators serendipitously discovered a new form of carbon: fullerenes. The most emblematic fullerene (i.e. C_{60} ``buckminsterfullerene''), contains exactly 60 carbon atoms organized in a cage-like structure similar to a soccer ball. Since their discovery impacted the field of nanotechnologies, Kroto and colleagues received the Nobel prize in 1996. The cage-like structure, common to all fullerene molecules, gives them unique properties, in particular an extraordinary stability. For this reason and since they were discovered in experiments aimed to reproduce conditions in space, fullerenes were sought after by astronomers for over two decades, and it is only recently that they have been firmly identified by spectroscopy, in evolved stars and in the interstellar medium. This identification offered the opportunity to study the molecular physics of fullerenes in the unique physical conditions provided by space, and to make the link with other large carbonaceous molecules thought to be present in space : polycyclic aromatic hydrocarbons.

Design aspects and clinical performance of the thrust plate hip prosthesis.

PubMed

Jacob, H A C; Bereiter, H H; Buergi, M L

2007-01-01

The thrust plate hip prosthesis (TPP) was conceived to maintain the physiological stress distribution in the proximal femur so as to prevent bone atrophy in this region, often encountered after implantation of conventional stem-type prostheses. A thrust plate of TiAlNb is firmly fixed to the neck of the femur by means of a forged CoCrMo bolt introduced through the lateral cortex, just below the greater trochanter, and through the metaphysis. A boss that contains the bolt head rests on the lateral cortex. A proximal extension from the thrust plate terminates in the ball head of the hip joint. Bone remodelling causes the initial prestressing of the structure (primary stability) to decline, but full integration of the thrust plate with the underlying host bone affords secondary stability. A total of 102 TPPs were implanted in the Cantonal Hospital, Chur, Switzerland, from 1992 to 1999 in 84 patients. The TPP was selected particularly for patients of the younger age group (26-76). Through its ability to load the medial cortex of the proximal femur in a physiological manner, the cortical bone in this region is preserved. The mean Harris hip score is 97 points and the survival rate 98 per cent, 144 months post-operatively.

The simulation of the alternate turbopump development high pressure oxygen and fuel turbopumps for the space shuttle main engine using the Shaberth computer program

NASA Technical Reports Server (NTRS)

Mcdonald, Gary H.

1988-01-01

The Space Shuttle Main Engine (SSME) is basically comprised of a combustion chamber and nozzle, high and low pressure oxygen turbopumps and high and low pressure fuel turbopumps. In the current configuration, the high pressure fuel (HPTFP) and high pressure oxygen turbopumps (HPOTP) have experienced a history of ball bearing wear. The wear problem can be attributed to numerous factors including the hydrodynamic axial and radial loads caused by the flow of liquid oxygen and liquid hydrogen through the turbopump impellers and turbine. Also, friction effects between the rolling elements, races, and cage can create thermally induced bearing geometry changes. To alleviate some of the current configuration problems, an alternate turbopump development (ATD) was proposed. However, the ATD HPOTP and HPTFP are constrained to operate interchangeably with the current turbopumps, thus, the operation conditions must be similar. The ATD configuration features a major change in bearings used to support the integrated shaft, impeller, and turbine system. A single ball and single roller will replace the pump-end and turbine and duplex ball bearings. The Shaft-Bearing-Thermal (SHABERTH) computer code was used to model the ATD HPOTP and ATD HPFTP configurations. A two bearing model was used to simulate the HPOTP and HPFTP bearings and shaft geometry. From SHABERTH, a comparison of bearing reaction loads, frictional heat generation rates, and Hertz contact stresses will be attempted with analysis at the 109 percent and 65 percent power levels.

Cryogenic Motor Enhancement for the NIRISS Instrument on the James Webb Space Telescope

NASA Astrophysics Data System (ADS)

Aldridge, David; Gentilhomme, Macso; Gibson, Andrew; Cameron, Peter; McColgan, Ashley; Dhanji, Zul; Lambros, Scott; Anderson, Mike

2015-09-01

Initial testing of the JWST NIRISS Dual Wheel Mechanism showed unsatisfactory life from the motors used to drive the individual wheel components. An investigation uncovered that theinternal friction had increased due to wear at the lubricated interface between the motor gearhead planetary gears and the planet gear retaining pins, reducing output torque. Work was undertaken to improve the life of this interface. Several design options were selected for development. A successful redesign was qualified with a larger gearhead, modified to use ball-bearings for planetary gear support. To further enhance life, all internal lubrication was changed to sputtered MoS2. PGM- HT cages were also employed for planetary and motor rotor bearings.

Modeling of rolling element bearing mechanics

NASA Technical Reports Server (NTRS)

Greenhill, L. M.

1991-01-01

Roller element bearings provide the primary mechanical interface between rotating and nonrotating components in the high performance turbomachinery of the Space Shuttle Main Engine (SSME). Knowledge of bearing behavior under various loading and environmental conditions is essential to predicting and understanding the overall behavior of turbopumps, including rotordynamic stability, critical speeds and bearing life. The objective is to develop mathematical models and computer programs to describe the mechanical behavior of ball and cylinder roller bearings under the loading and environmental conditions encountered in the SSME and future high performance rocket engines. This includes characteristics such as nonlinear load/motion relationships, stiffness and damping, rolling element loads for life prediction, and roller and cage stability.

Fullerene materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malhotra, R.; Ruoff, R.S.; Lorents, D.C.

1995-04-01

Fullerenes are all-carbon cage molecules. The most celebrated fullerene is the soccer-ball shaped C{sub 60}, which is composed of twenty hexagons and twelve pentagons. Because its structure is reminiscent of the geodesic domes of architect R. Buckminster Fuller, C{sub 60} is called buckminsterfullerene, and all the materials in the family are designated fullerenes. Huffman and Kraetschmer`s discovery unleashed activity around the world as scientists explored production methods, properties, and potential uses of fullerenes. Within a short period, methods for their production in electric arcs, plasmas, and flames were discovered, and several companies began selling fullerenes to the research market. Whatmore » is remarkable is that in all these methods, carbon atoms assemble themselves into cage structures. The capability for self-assembly points to some inherent stability of these structures that allows their formation. The unusual structure naturally leads to unusual properties. Among them are ready solubility in solvents and a relatively high vapor pressure for a pure carbon material. The young fullerene field has already produced a surprising array of structures for the development of carbon-base materials having completely new and different properties from any that were previously possible.« less

Benefits of a Ball and Chain: Simple Environmental Enrichments Improve Welfare and Reproductive Success in Farmed American Mink (Neovison vison)

PubMed Central

Meagher, Rebecca K.; Ahloy Dallaire, Jamie; Campbell, Dana L. M.; Ross, Misha; Møller, Steen H.; Hansen, Steffen W.; Díez-León, María; Palme, Rupert; Mason, Georgia J.

2014-01-01

Can simple enrichments enhance caged mink welfare? Pilot data from 756 sub-adults spanning three colour-types (strains) identified potentially practical enrichments, and suggested beneficial effects on temperament and fur-chewing. Our main experiment started with 2032 Black mink on three farms: from each of 508 families, one juvenile male-female pair was enriched (E) with two balls and a hanging plastic chain or length of hose, while a second pair was left as a non-enriched (NE) control. At 8 months, more than half the subjects were killed for pelts, and 302 new females were recruited (half enriched: ‘late E’). Several signs of improved welfare or productivity emerged. Access to enrichment increased play in juveniles. E mink were calmer (less aggressive in temperament tests; quieter when handled; less fearful, if male), and less likely to fur-chew, although other stereotypic behaviours were not reduced. On one farm, E females had lower cortisol (inferred from faecal metabolites). E males tended to copulate for longer. E females also weaned more offspring: about 10% more juveniles per E female, primarily caused by reduced rates of barrenness (‘late E’ females also giving birth to bigger litters on one farm), effects that our data cautiously suggest were partly mediated by reduced inactivity and changes in temperament. Pelt quality seemed unaffected, but E animals had cleaner cages. In a subsidiary side-study using 368 mink of a second colour-type (‘Demis’), similar temperament effects emerged, and while E did not reduce fur-chewing or improve reproductive success in this colour-type, E animals were judged to have better pelts. Overall, simple enrichments were thus beneficial. These findings should encourage welfare improvements on fur farms (which house 60-70 million mink p.a.) and in breeding centres where endangered mustelids (e.g. black-footed ferrets) often reproduce poorly. They should also stimulate future research into more effective practical enrichments. PMID:25386726

Benefits of a ball and chain: simple environmental enrichments improve welfare and reproductive success in farmed American mink (Neovison vison).

PubMed

Meagher, Rebecca K; Ahloy Dallaire, Jamie; Campbell, Dana L M; Ross, Misha; Møller, Steen H; Hansen, Steffen W; Díez-León, María; Palme, Rupert; Mason, Georgia J

2014-01-01

Can simple enrichments enhance caged mink welfare? Pilot data from 756 sub-adults spanning three colour-types (strains) identified potentially practical enrichments, and suggested beneficial effects on temperament and fur-chewing. Our main experiment started with 2032 Black mink on three farms: from each of 508 families, one juvenile male-female pair was enriched (E) with two balls and a hanging plastic chain or length of hose, while a second pair was left as a non-enriched (NE) control. At 8 months, more than half the subjects were killed for pelts, and 302 new females were recruited (half enriched: 'late E'). Several signs of improved welfare or productivity emerged. Access to enrichment increased play in juveniles. E mink were calmer (less aggressive in temperament tests; quieter when handled; less fearful, if male), and less likely to fur-chew, although other stereotypic behaviours were not reduced. On one farm, E females had lower cortisol (inferred from faecal metabolites). E males tended to copulate for longer. E females also weaned more offspring: about 10% more juveniles per E female, primarily caused by reduced rates of barrenness ('late E' females also giving birth to bigger litters on one farm), effects that our data cautiously suggest were partly mediated by reduced inactivity and changes in temperament. Pelt quality seemed unaffected, but E animals had cleaner cages. In a subsidiary side-study using 368 mink of a second colour-type ('Demis'), similar temperament effects emerged, and while E did not reduce fur-chewing or improve reproductive success in this colour-type, E animals were judged to have better pelts. Overall, simple enrichments were thus beneficial. These findings should encourage welfare improvements on fur farms (which house 60-70 million mink p.a.) and in breeding centres where endangered mustelids (e.g. black-footed ferrets) often reproduce poorly. They should also stimulate future research into more effective practical enrichments.

Tribocorrosion behavior of CoCrMo alloy for hip prosthesis as a function of loads: a comparison between two testing systems

PubMed Central

Mathew, M.T.; Runa, M.J.; Laurent, M.; Jacobs, J.J.; Rocha, L.A.; Wimmer, M.A.

2011-01-01

Metal-on-metal (MOM) hip prosthesis bearings have enjoyed renewed popularity, but concerns remain with wear debris and metal ion release causing a negative response in the surrounding tissues. Further understanding into the wear and corrosion mechanisms occurring in MOM hips is therefore essential. The purpose of this study was to evaluate the tribocorrosion behaviour, or interplay between corrosion and wear, of a low-carbon CoCrMo alloy as a function of loading. The tribocorrosion tests were performed using two tribometer configurations. In the first configuration, “System A”, a linearly reciprocating alumina ball slid against the flat metal immersed in a phosphate buffer solution (PBS). In the second configuration, “System B”, the flat end of a cylindrical metal pin was pressed against an alumina ball that oscillated rotationally, using bovine calf serum (BCS) as the lubricant and electrolyte. System B was custom-built to emulate in vivo conditions. The tribocorrosion tests were performed under potentiostatic conditions at -0.345V, with a sliding duration of 1800 seconds and a frequency of 1Hz. In System A the applied loads were 0.05, 0.5, and 1N (138, 296 and 373MPa, respectively) and in System B were 16, 32, and 64N (474, 597, and 752MPa, respectively). Electrochemical impedance spectroscopy (EIS) and polarization resistance were estimated. The total mass loss (Kwc) in the CoCrMo was determined. The mass loss due to wear (Kw) and that due to corrosion (Kc) were determined. The dominant wear regime for the CoCrMo alloy subjected to sliding changes from wear-corrosion to mechanical wear as the contact stress increases. An attempt was made to compare both system, in their tribochemical responses and formulate some insights in the total degradation processes. Our results also suggest that the proteins in the serum lubricant assist in the generation of a protective layer against corrosion during sliding. The study highlights the need of adequate methodology/guidelines to compare the results from different test systems and translating in solving the practical problems. PMID:21921971

Comparison of retention and stability of two implant-retained overdentures based on implant location.

PubMed

Scherer, Michael D; McGlumphy, Edwin A; Seghi, Robert R; Campagni, Wayne V

2014-09-01

The location of dental implants and the choice of retentive attachments for implant-retained overdentures are selected based on clinician preference, expert opinion, or empirical information. Limited information is available regarding implant position and the effect on the retention and stability of 2-implant mandibular implant overdentures. The purpose of this investigation was to evaluate the effect of implant location on the in vitro retention and stability of a simulated 2-implant-supported overdenture and to examine the differences among different attachment systems. A model that simulates a mandibular edentulous ridge with dental implants in positions that approximate tooth positions, and a cobalt-chromium cast framework attached to a universal testing machine was used to measure the peak load (N) required to disconnect the attachments. Four different types of attachments (Ball/Cap, ERA, Locator, and O-Ring) were used in sequence in various positions on the model to evaluate the effect of implant location on the retention and stability of a simulated 2-implant-retained overdenture. Means were calculated, and differences among the systems, directions, and groups were identified by using a repeated measured ANOVA (α=.05). For differences observed between measurements, the Bonferroni post hoc method at the 5% level of significance was used to determine the location and magnitude of difference. The interactions between the attachment system, direction of force, and implant location were statistically significant (P=.01). The vertical retention and horizontal stability of a simulated overdenture prosthesis increased with the distal implant location up to the second premolar, and the anteroposterior stability increased with distal implant location. The attachment type affected retention and stability differently by location. Ball attachments produced the highest levels of retention and stability, followed by Locator (pink), O-Ring, and ERA (orange). The retention and stability of a 2-implant simulated overdenture prosthesis is significantly affected by implant location (P=.01) and abutment type (P=.01). Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Spatial cognition in a virtual reality home-cage extension for freely moving rodents

PubMed Central

Kaupert, Ursula; Frei, Katja; Bagorda, Francesco; Schatz, Alexej; Tocker, Gilad; Rapoport, Sophie; Derdikman, Dori

2017-01-01

Virtual reality (VR) environments are a powerful tool to investigate brain mechanisms involved in the behavior of animals. With this technique, animals are usually head fixed or secured in a harness, and training for cognitively more complex VR paradigms is time consuming. A VR apparatus allowing free animal movement and the constant operator-independent training of tasks would enable many new applications. Key prospective usages include brain imaging of animal behavior when carrying a miniaturized mobile device such as a fluorescence microscope or an optetrode. Here, we introduce the Servoball, a spherical VR treadmill based on the closed-loop tracking of a freely moving animal and feedback counterrotation of the ball. Furthermore, we present the complete integration of this experimental system with the animals’ group home cage, from which single individuals can voluntarily enter through a tunnel with radio-frequency identification (RFID)-automated access control and commence experiments. This automated animal sorter functions as a mechanical replacement of the experimenter. We automatically trained rats using visual or acoustic cues to solve spatial cognitive tasks and recorded spatially modulated entorhinal cells. When electrophysiological extracellular recordings from awake behaving rats were performed, head fixation can dramatically alter results, so that any complex behavior that requires head movement is impossible to achieve. We circumvented this problem with the use of the Servoball in open-field scenarios, as it allows the combination of open-field behavior with the recording of nerve cells, along with all the flexibility that a virtual environment brings. This integrated home cage with a VR arena experimental system permits highly efficient experimentation for complex cognitive experiments. NEW & NOTEWORTHY Virtual reality (VR) environments are a powerful tool for the investigation of brain mechanisms. We introduce the Servoball, a VR treadmill for freely moving rodents. The Servoball is integrated with the animals’ group home cage. Single individuals voluntarily enter using automated access control. Training is highly time-efficient, even for cognitively complex VR paradigms. PMID:28077665

Use of piezoelectric actuators in active vibration control of rotating machinery

NASA Technical Reports Server (NTRS)

Lin, Reng Rong; Palazzolo, Alan B.; Kascak, Albert F.; Montague, Gerald

1990-01-01

Theoretical and test results for the development of piezoelectric-actuator-based active vibration control (AVC) are presented. The evolution of this technology starts with an ideal model of the actuator and progresses to a more sophisticated model where the pushers force the squirrel cage ball bearing supports of a rotating shaft. The piezoelectric pushers consist of a stack of piezoelectric ceramic disks that are arranged on top of one another and connected in parallel electrically. This model consists of a prescribed displacement that is proportional to the input voltage and a spring that represents the stiffness of the stack of piezoelectric disks. System tests were carried out to stabilize the AVC system, verify its effectiveness in controlling vibration, and confirm the theory presented.

Fabrication of inorganic molybdenum disulfide fullerenes by arc in water

NASA Astrophysics Data System (ADS)

Sano, Noriaki; Wang, Haolan; Chhowalla, Manish; Alexandrou, Ioannis; Amaratunga, Gehan A. J.; Naito, Masakazu; Kanki, Tatsuo

2003-01-01

Closed caged fullerene-like molybdenum disulfide (MoS 2) nano-particles were obtained via an arc discharge between a graphite cathode and a molybdenum anode filled with microscopic MoS 2 powder submerged in de-ionized water. A statistical study of over 150 polyhedral fullerene-like MoS 2 nano-particles in plan view transmission electron microscopy revealed that the majority consisted of 2-3 layers with diameters of 5-15 nm. We show that the nano-particles are formed by seamless folding of MoS 2 sheets. A model based on the agglomeration of MoS 2 fragments over an extreme temperature gradient around a plasma ball in water is proposed to explain the formation of nano-particles.

SHABERTH - ANALYSIS OF A SHAFT BEARING SYSTEM (CRAY VERSION)

NASA Technical Reports Server (NTRS)

Coe, H. H.

1994-01-01

The SHABERTH computer program was developed to predict operating characteristics of bearings in a multibearing load support system. Lubricated and non-lubricated bearings can be modeled. SHABERTH calculates the loads, torques, temperatures, and fatigue life for ball and/or roller bearings on a single shaft. The program also allows for an analysis of the system reaction to the termination of lubricant supply to the bearings and other lubricated mechanical elements. SHABERTH has proven to be a valuable tool in the design and analysis of shaft bearing systems. The SHABERTH program is structured with four nested calculation schemes. The thermal scheme performs steady state and transient temperature calculations which predict system temperatures for a given operating state. The bearing dimensional equilibrium scheme uses the bearing temperatures, predicted by the temperature mapping subprograms, and the rolling element raceway load distribution, predicted by the bearing subprogram, to calculate bearing diametral clearance for a given operating state. The shaft-bearing system load equilibrium scheme calculates bearing inner ring positions relative to the respective outer rings such that the external loading applied to the shaft is brought into equilibrium by the rolling element loads which develop at each bearing inner ring for a given operating state. The bearing rolling element and cage load equilibrium scheme calculates the rolling element and cage equilibrium positions and rotational speeds based on the relative inner-outer ring positions, inertia effects, and friction conditions. The ball bearing subprograms in the current SHABERTH program have several model enhancements over similar programs. These enhancements include an elastohydrodynamic (EHD) film thickness model that accounts for thermal heating in the contact area and lubricant film starvation; a new model for traction combined with an asperity load sharing model; a model for the hydrodynamic rolling and shear forces in the inlet zone of lubricated contacts, which accounts for the degree of lubricant film starvation; modeling normal and friction forces between a ball and a cage pocket, which account for the transition between the hydrodynamic and elastohydrodynamic regimes of lubrication; and a model of the effect on fatigue life of the ratio of the EHD plateau film thickness to the composite surface roughness. SHABERTH is intended to be as general as possible. The models in SHABERTH allow for the complete mathematical simulation of real physical systems. Systems are limited to a maximum of five bearings supporting the shaft, a maximum of thirty rolling elements per bearing, and a maximum of one hundred temperature nodes. The SHABERTH program structure is modular and has been designed to permit refinement and replacement of various component models as the need and opportunities develop. A preprocessor is included in the IBM PC version of SHABERTH to provide a user friendly means of developing SHABERTH models and executing the resulting code. The preprocessor allows the user to create and modify data files with minimal effort and a reduced chance for errors. Data is utilized as it is entered; the preprocessor then decides what additional data is required to complete the model. Only this required information is requested. The preprocessor can accommodate data input for any SHABERTH compatible shaft bearing system model. The system may include ball bearings, roller bearings, and/or tapered roller bearings. SHABERTH is written in FORTRAN 77, and two machine versions are available from COSMIC. The CRAY version (LEW-14860) has a RAM requirement of 176K of 64 bit words. The IBM PC version (MFS-28818) is written for IBM PC series and compatible computers running MS-DOS, and includes a sample MS-DOS executable. For execution, the PC version requires at least 1Mb of RAM and an 80386 or 486 processor machine with an 80x87 math co-processor. The standard distribution medium for the IBM PC version is a set of two 5.25 inch 360K MS-DOS format diskettes. The contents of the diske

From here to paternity: neural correlates of the onset of paternal behavior in California mice (Peromyscus californicus).

PubMed

de Jong, Trynke R; Chauke, Miyetani; Harris, Breanna N; Saltzman, Wendy

2009-08-01

In a minority of mammalian species, including humans, fathers play a significant role in infant care. Compared to maternal behavior, the neural and hormonal bases of paternal care are poorly understood. We analyzed behavioral, neuronal and neuropeptide responses towards unfamiliar pups in biparental California mice, comparing males housed with another male ("virgin males") or with a female before ("paired males") or after ("new fathers") the birth of their first litter. New fathers approached pups more rapidly and spent more time engaging in paternal behavior than virgin males. In each cage housing two virgin males, one was spontaneously paternal and one was not. New fathers and paired males spent more time sniffing and touching a wire mesh ball containing a newborn pup than virgin males. Only new fathers showed significantly increased Fos-like immunoreactivity in the medial preoptic nucleus (MPO) following exposure to a pup-containing ball, as compared to an empty ball. Moreover, Fos-LIR in the bed nucleus of the stria terminalis (STMV and STMPM) and caudal dorsal raphe nucleus (DRC) was increased in new fathers, independent of test condition. No differences were found among the groups in Fos-LIR in oxytocinergic or vasopressinergic neurons. These results suggest that sexual and paternal experiences facilitate paternal behavior, but other cues play a role as well. Paternal experience increases Fos-LIR induced by distal pup cues in the MPO, but not in oxytocin and vasopressin neurons. Fatherhood also appears to alter neurotransmission in the BNST and DRC, regions implicated in emotionality and stress-responsiveness.

Pattern of External Breast Prosthesis Use by Post Mastectomy Breast Cancer Patients in India: Descriptive Study from Tertiary Care Centre.

PubMed

Ramu, D; Ramesh, Rakesh S; Manjunath, Suraj; Shivakumar; Goel, Vipin; Hemnath, G N; Alexander, Annie

2015-12-01

In India, Breast cancer is now the most common cancer in urban and 2nd most common in rural areas [1]. The incidence is rising, more younger women are getting affected and due to increase in survival rates there is an increase in the total number of women suffering from breast Cancer. So far there are no studies evaluating the pattern of breast prosthesis use in Indian scenario. The aim of this study is to address the patterns of external breast prosthesis used in India and view of Indian women on such prosthesis after mastectomy for breast cancer. This was a descriptive longitudinal study. In this study we interviewed (telephonic) 63 people, after three years of completing treatment under The Department of Surgical Oncology, St. Johns medical college, Bangalore. Among the study group, 27 members (40 %) were using various prosthesis, rest 36 women were not using any type of prosthesis. Among the users of prosthesis, silicon prosthesis was used by 6 women, padded cups by 8 women, cloth or cotton by 12 women and 1 woman used other type of prosthesis. Most women use simple items like cloth and cotton (44 %). Next most commonly used prosthesis are padded cups(). Only 22 % of women were found using silicon prosthesis in this study. Most of the well educated patients used external prosthesis either in the form of silicon prosthesis or padded cups. Most of women below age of 50 used external breast prosthesis. Use of prosthesis was more in urban compared to rural population (48 % vs 25 %). Prosthesis users worried more about the body image than women not using prosthesis. 25 % of women using prosthesis had body image issues where as only 5 % of non prosthesis users had such problems. Prosthesis users need improvement in terms of comfort, size, shape and affordability. Most common reasons for not using prosthesis are age, lack of motivation and awareness. Less than half of the women included in this study used external prosthesis after mastectomy for breast cancer. Most of the women are used home made prosthesis like cloth and cotton (44.4 %). Education, age and urban status are the strong factors which influences use of prosthesis. Prosthesis users are those who are more concerned about their body image. There is a palpable need to develop better prosthesis at affordable price.

The valve choice in tricuspid valve replacement: 25 years of experience.

PubMed

Van Nooten, G J; Caes, F L; François, K J; Taeymans, Y; Primo, G; Wellens, F; Leclerq, J L; Deuvaert, F E

1995-01-01

This study reviews 146 consecutive patients who underwent tricuspid valve replacement (TVR) with 69 bioprostheses (porcine and bovine pericardial) and 77 mechanical ball, disc or bileaflet valves between 1967 and 1987. The mean age was 51.4 +/- 12.1 years. Preoperatively, 97% were in New York Heart Association (NYHA) functional class III or more and over 40% had undergone previous cardiac surgery. Hospital mortality was high (16.1%). Incremental risk factors for hospital death were preoperative icterus (P < 0.01), hepatomegaly (P = 0.02), NYHA functional class IV (P = 0.02) and male sex (P = 0.04) (univariate analysis). Ninety-eight percent of the hospital survivors were followed up for a mean of 92 months. Cumulative follow-up added up to 955 patient-years. There were 70 late deaths. The actuarial survival rate was 74% at 60 months and less than 25% at 14 years. Incremental risk factors for late death indicated by univariate analysis were the type of tricuspid prosthesis (Smel-off-Cutter and Kay-Shiley prostheses) (P = 0.04), the type of operative myocardial protection (normothermia and coronary perfusion) (P = 0.05) and preoperative NYHA functional class IV (P = 0.05). We conclude that TVR carries a high operative risk and poor long-term survival, both influenced by preoperative and perioperative variables. Bearing in mind the poor prognosis for TVR, we prefer a large-sized bioprosthesis, in view of its initial good durability and low risk of valve-related events. However, in patients with good life expectancy, a bileaflet mechanical prosthesis may be an acceptable alternative.

History of Space Shuttle Main Engine Turbopump Bearing Testing at the Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Gibson, Howard; Thom, Robert; Moore, Chip; Haluck, Dave

2010-01-01

The Space Shuttle is propelled into orbit by two solid rocket motors and three liquid fed main engines. After the solid motors fall away, the shuttle engines continue to run for a total time of 8 minutes. These engines are fed propellants by low and high pressure turbopumps. A critical part of the turbopump is the main shaft that supports the drive turbine and the pump inducer and impeller. Rolling element bearings hold the shaft in place during rotation. If the bearings were to fail, the shaft would move, allowing components to rub in a liquid oxygen or hydrogen environment, which could have catastrophic results. These bearings are required to spin at very high speeds, support radial and axial loads, and have high wear resistance without the benefit of a conventional means of lubrication. The Rocketdyne built Shuttle turbopumps demonstrated their capability to perform during launches; however, the seven hour life requirement was not being met. One of the limiting factors was the bearings. In the late 1970's, an engineering team was formed at the Marshall Space Flight Center (MSFC), to develop a test rig and plan for testing the Shuttle s main engine high pressure oxygen turbopump (HPOTP) bearings. The goals of the program were to better understand the operation of bearings in a cryogenic environment and to further develop and refine existing computer models used to predict the operational limits of these bearings. In 1982, testing began in a rig named the Bearing and Seal Material Tester or BSMT as it was commonly called. The first testing investigated the thermal margin and thermal runaway limits of the HPOTP bearings. The test rig was later used to explore potential bearing improvements in the area of increased race curvatures, new cage materials for better lubrication, new wear resistant rolling element materials, and other ideas to improve wear life. The most notable improvements during this tester s time was the incorporation of silicon nitride balls and bronze filled polytetrafluoroethylene (PTFE) cage inserts into the bearings and the anchoring of the SHABERTH bearing model and SINDA thermal computer model for cryogenic bearing analysis. In the mid 1990's, Pratt and Whitney (P&W) won the contract to deliver new high pressure turbopumps for the Shuttle s engines. P&W used two new bearing materials for the rings, Cronidur 30 and AISI 9310 steel and testing was needed on these new materials. A test rig had been designed and delivered to MSFC for testing hydrostatic bearings but with the need by Pratt to validate their bearings, the rig was reconfigured for testing of two ball bearings or a ball bearing and a roller bearing. The P&W bearings are larger than the Rocketdyne bearings and could not be installed in the BSMT. This new test rig was called the LH2 test rig and began operation in 1995. The LH2 test rig accumulated 75,000 seconds of run time in hydrogen. This test rig was valuable in two areas: validating the use of silicon nitride balls and rollers in Alternate Turbopump Development (ATD) bearings, which Pratt eventually used, and in proving the robustness of the balls and rollers after river marks appeared on the surface of the rolling elements. Individual test reports have been presented at conferences and symposiums throughout the years. This paper is a comprehensive report of all the bearing testing done at Marshall. It represents thousands of hours of dedication and labor in all engineering and technical fields that made this program a success.

Association between dental prosthesis need, nutritional status and quality of life of elderly subjects.

PubMed

Pillai, Rajath Sasidharan; Mathur, Vijay Prakash; Jain, Veena; Shah, Naseem; Kalra, Sandeep; Kumar, Pravesh; Dey, A B

2015-12-01

To determine the effect of prosthesis need on nutritional status and oral health-related quality of life (OHrQoL) in elderly and to check the disparity between prosthesis need and prosthesis want in the Indian elderly. A total of 946 geriatric participants reporting to a geriatric medicine clinic were recruited in the study. Mini-nutritional assessment (MNA), geriatric oral health assessment (GOHAI) indices, prosthesis need according to WHO criteria, and prosthesis want was recorded along with age, gender, socioeconomic status and posterior occluding pair. Significant associations exist between prosthesis need and age (p = 0.005), MNA (p = 0.006) and GOHAI (p = 0.000). Prosthesis demand too was influenced by age (p = 0.004), posterior occluding pairs (p = 0.000), MNA (p = 0.012) and GOHAI (p = 0.000). GOHAI was negatively correlated with upper (r = -0.445) and lower prosthesis need (r = -0.460). Participants with some prosthesis need had significantly lower MNA and GOHAI scores as compared to those with no prosthesis need. Though prosthesis need was high (79.7 %), demand was low (39.3 %). Prosthesis need affects nutritional status and OHrQoL in elderly, and a wide gap exists between need and want of prosthesis.

Quantum interference experiments with large molecules

NASA Astrophysics Data System (ADS)

Nairz, Olaf; Arndt, Markus; Zeilinger, Anton

2003-04-01

Wave-particle duality is frequently the first topic students encounter in elementary quantum physics. Although this phenomenon has been demonstrated with photons, electrons, neutrons, and atoms, the dual quantum character of the famous double-slit experiment can be best explained with the largest and most classical objects, which are currently the fullerene molecules. The soccer-ball-shaped carbon cages C60 are large, massive, and appealing objects for which it is clear that they must behave like particles under ordinary circumstances. We present the results of a multislit diffraction experiment with such objects to demonstrate their wave nature. The experiment serves as the basis for a discussion of several quantum concepts such as coherence, randomness, complementarity, and wave-particle duality. In particular, the effect of longitudinal (spectral) coherence can be demonstrated by a direct comparison of interferograms obtained with a thermal beam and a velocity selected beam in close analogy to the usual two-slit experiments using light.

Use of permethrin eradicated the tropical rat mite (Ornithonyssus bacoti) from a colony of mutagenized and transgenic mice.

PubMed

Hill, William A; Randolph, Mildred M; Boyd, Keli L; Mandrell, Timothy D

2005-09-01

The tropical rat mite, Ornithonyssus bacoti, was identified in a colony of mutagenized and transgenic mice at a large academic institution. O. bacoti is an obligate, blood-feeding ectoparasite with an extensive host range. Although the source of the infestation was likely feral rodents, none were found in the room housing infested mice. We hypothesize that construction on the floor above the vivarium and compromised ceiling integrity within the animal room provided for vermin entry and subsequent O. bacoti infestation. O. bacoti infestation was eliminated by environmental decontamination with synthetic pyrethroids and weekly application of 7.4% permethrin-impregnated cotton balls to mouse caging for five consecutive weeks. Visual examination of the macroenvironment, microenvironment, and colony for 38 days confirmed the efficacy of treatment. We noted no treatment-related toxicities or effects on colony production.

Custom-made ocular prosthesis.

PubMed

Gunaseelaraj, Rajkumar; Karthikeyan, Suma; Kumar, Mohan N; Balamurugan, T; Jagadeeshwaran, A R

2012-08-01

An ocular defect may affect a patient psychologically. An ocular prosthesis is given to uplift the patient psychologically and improve the confidence. Ocular prosthesis can be custom made or a stock shell. To improve the comfort and matching of the prosthesis with that of the adjacent natural eye an custom made ocular prosthesis is preferred. Different techniques are available to fabricate a custom ocular prosthesis, here we have used paper iris disk technique.

Experiences in the provision, fitting and supply of external breast prostheses: findings from a national survey.

PubMed

Gallagher, P; Buckmaster, A; O'Carroll, S; Kiernan, G; Geraghty, J

2009-11-01

A good-quality external breast prosthesis and prosthesis-fitting service is integral to recovery post-mastectomy. However, this area of care has minimal information or research available. The aim of this study was to investigate women's experience of the provision, fitting, supply and use of breast prostheses in Ireland. Three national surveys were undertaken with women (n = 527), breast care nurses (BCNs) (n = 32) and retail prosthesis fitters (n = 12). The findings identified the importance of the prosthesis for shape, appearance to self, appearance to others, sense of well-being, self-confidence and femininity. Dissatisfaction with weight, comfort and movement of the prosthesis was identified. Cost and travel distance were found to influence the replacement of the prosthesis. Dissatisfaction emerged with the display and choice of products, and brochure availability at the prosthesis fitting. Women preferred to be fitted for the first silicone prosthesis by a BCN in a hospital setting whereas for the replacement prosthesis they preferred a trained fitter at a specialized prosthesis supplier. BCNs and retail fitters identified the need for service guidelines and increased availability of professional development opportunities in prosthesis-fitting. These findings contributed to the development of standards of care for breast prosthesis-fitting services to benefit women and to provide guidelines for those providing the service.

Effect of pulsed duty cycle control on tribological and corrosion properties of AISI-316 in cathodic cage plasma nitriding

NASA Astrophysics Data System (ADS)

Naeem, M.; Raza, H. A.; Shafiq, M.; Zaka-ul-Islam, M.; Iqbal, Javed; Díaz-Guillén, J. C.; Zakaullah, M.

2017-11-01

Austenitic stainless steels are of prime importance in many industrial sectors because of their excellent corrosion resistance; however, their poor mechanical and tribological features lead to their reduced applicability. In this regard, low-temperature cathodic cage plasma nitriding (CCPN) can be used to improve surface properties of steels without scarifying the inherent corrosion resistance. In this study, AISI-316 samples are processed in CCPN reactor at a temperature of 400 °C, for the treatment time of 4 h, at a pressure of 150 Pa and variable pulsed duty cycle (15-75%). The microstructure and mechanical features are analyzed using x-ray diffraction, scanning electron microscopy, microhardness tester and ball-on-disc wear tester. The anodic polarization test in 3.5% NaCl is conducted to examine the corrosion properties. The results show that hardness is enhanced up to 1327 HV at low duty cycle, which is considerably higher than base material (278 HV). The wear rate is found to be reduced up to 90% over base material by processing at low duty cycle. The base material exhibits severe abrasive wear, and the nitrided sample has dominant adhesive wear. The corrosion rate is found to be reduced up to 95% over base material for the sample nitrided at low duty cycle. This study shows that wear and corrosion resistance in CCPN can be significantly boosted by reducing the pulsed duty cycle.

Sleep disturbance induces neuroinflammation and impairment of learning and memory.

PubMed

Zhu, Biao; Dong, Yuanlin; Xu, Zhipeng; Gompf, Heinrich S; Ward, Sarah A P; Xue, Zhanggang; Miao, Changhong; Zhang, Yiying; Chamberlin, Nancy L; Xie, Zhongcong

2012-12-01

Hospitalized patients can develop cognitive function decline, the mechanisms of which remain largely to be determined. Sleep disturbance often occurs in hospitalized patients, and neuroinflammation can induce learning and memory impairment. We therefore set out to determine whether sleep disturbance can induce neuroinflammation and impairment of learning and memory in rodents. Five to 6-month-old wild-type C57BL/6J male mice were used in the studies. The mice were placed in rocking cages for 24 h, and two rolling balls were present in each cage. The mice were tested for learning and memory function using the Fear Conditioning Test one and 7 days post-sleep disturbance. Neuroinflammation in the mouse brain tissues was also determined. Of the Fear Conditioning studies at one day and 7 days after sleep disturbance, twenty-four hour sleep disturbance decreased freezing time in the context test, which assesses hippocampus-dependent learning and memory; but not the tone test, which assesses hippocampus-independent learning and memory. Sleep disturbance increased pro-inflammatory cytokine IL-6 levels and induced microglia activation in the mouse hippocampus, but not the cortex. These results suggest that sleep disturbance induces neuroinflammation in the mouse hippocampus, and impairs hippocampus-dependent learning and memory in mice. Pending further studies, these findings suggest that sleep disturbance-induced neuroinflammation and impairment of learning and memory may contribute to the development of cognitive function decline in hospitalized patients. Copyright © 2012 Elsevier Inc. All rights reserved.

Comparison of three-implant-supported fixed dentures and two-implant-retained overdentures in the edentulous mandible: a pilot study of treatment efficacy and patient satisfaction.

PubMed

De Kok, Ingeborg J; Chang, Kuang-Han; Lu, Tsui-Shan; Cooper, Lyndon F

2011-01-01

The mandibular two-implant overdenture has been shown to be a highly successful treatment. However, overdenture patients who desire a fixed prosthesis may not be satisfied with a removable overdenture. This prospective study sought to compare prosthetic outcomes, patient satisfaction, and survival rates of implants between two-implant-supported overdentures (IODs) and three-implant-supported fixed dentures (ISFDs). Twenty completely edentulous patients were randomly and equally assigned to two groups. New conventional complete dentures were made, and the mandibular denture was used as a surgical guide during implant placement. Implants were placed in one stage, followed by a mandibular denture soft reline (provisional loading). Ball attachments were inserted at 8 weeks, and ISFDs were delivered at 16 weeks. IODs were connected to the attachments at 8 weeks, using each patients's existing denture. The definitive ISFDs were fabricated using computer-aided design/computer-assisted manufacture milled titanium frameworks and acrylic resin base and teeth. Patient satisfaction and panoramic radiographs were investigated at 6 and 12 months. Both treatments had significant and positive effects on patient satisfaction and quality of life. None of the 50 implants placed had failed at 12 months of follow-up; therefore, the implant survival rate was 100%. Prosthetic complications were generally rare and easily manageable. Both the treatment modalities-the ISFD supported by three implants and the IOD supported by two implants-significantly and similarly improved patient satisfaction and oral health-related quality of life, and prosthetic complications were relatively rare for both treatments. Three implants can be used to support a mandibular fixed prosthesis; however, a longer observation period is needed to validate this treatment modality.

Sockets Manufactured by CAD/CAM Method Have Positive Effects on the Quality of Life of Patients With Transtibial Amputation.

PubMed

Karakoç, Mehmet; Batmaz, İbrahim; Sariyildiz, Mustafa Akif; Yazmalar, Levent; Aydin, Abdülkadir; Em, Serda

2017-08-01

Patients with amputation need prosthesis to comfortably move around. One of the most important parts of a good prosthesis is the socket. Currently, the most commonly used method is the traditional socket manufacturing method, which involves manual work; however, computer-aided design/computer-aided manufacturing (CAD/CAM) is also being used in the recent years. The present study aimed to investigate the effects of sockets manufactured by traditional and CAD/CAM method on clinical characteristics and quality of life of patients with transtibial amputation. The study included 72 patients with transtibial amputation using prosthesis, 36 of whom had CAD/CAM prosthetic sockets (group 1) and 36 had traditional prosthetic sockets (group 2). Amputation reason, prosthesis lifetime, walking time and distance with prosthesis, pain-free walking time with prosthesis, production time of the prosthesis, and adaptation time to the prosthesis were questioned. Quality of life was assessed using the 36-item Short Form Health Survey questionnaire and the Trinity Amputation and Prosthesis Experience Scales. Walking time and distance and pain-free walking time with prosthesis were significantly better in group 1 than those in group 2. Furthermore, the prosthesis was applied in a significantly shorter time, and socket adaptation time was significantly shorter in group 1. Except emotional role limitation, all 36-item Short Form Healthy Survey questionnaire parameters were significantly better in group 1 than in group 2. Trinity Amputation and Prosthesis Experience Scales activity limitation scores of group 1 were lower, and Trinity Amputation and Prosthesis Experience Scales satisfaction with the prosthesis scores were higher than those in group 2. Our study demonstrated that the sockets manufactured by CAD/CAM methods yield better outcomes in quality of life of patients with transtibial amputation than the sockets manufactured by the traditional method.

Aesthetic treatment of pectus excavatum: a new endoscopic technique using a porous polyethylene implant.

PubMed

Grappolini, Simone; Fanzio, Paolo M; D'Addetta, Pierluca G C; Todde, Alberto; Infante, Maurizio

2008-01-01

Pectus excavatum is the most frequent malformation of the rib cage. Functional aspects associated with this malformation often are absent even in adults not involved in competitive sports activities. Overall, these patients often live with extreme psychological discomfort when the malformations are minor. Traditionally, the correction of these malformations has been geared toward interventions that modify the architecture of the rib cage. However, all these interventions, even the most recent, involve considerably invasive major surgery. In fact, optimal results are not always achieved with corrective surgery using the insertion of silicone prosthesis, and patients often experience complications. To correct intermediate and modest pectus excavatum in a stable manner and with the least amount of invasiveness, the authors developed a camouflage technique that uses porous prostheses made from high-density linear polyethylene. This material is generally used for reconstruction of the brain case. Between February 2001 and March 2006, in the I Unit of Plastic Surgery of the authors' Institute, 11 adult pectus excavatum patients with no previous cardiorespiratory symptoms underwent the authors' surgical technique. The average patient age was 29 years. Surgical repair was successful in all cases, and the average hospital stay was short. There were no complications during the follow-up period. The described approach repairs nonfunctional pectus excavatum in the adult with satisfying aesthetic and stable results, short hospital stay, and high patient popularity ratings. The best therapeutic option for pectus excavatum, especially with intermediate or moderate severity, is still controversial: thoracic surgery or camouflage surgery with implant? Trying to address those issues we propose a new technique by a multidisciplinary, not aggressive approach using a high density linear polyethylene implant and Omentus flap and the early analysis of our data.

Women's Satisfaction with Their Breast Prosthesis: What Determines a Quality Prosthesis?

ERIC Educational Resources Information Center

Livingston, Patricia M.; White, Victoria M.; Roberts, Susan B.; Pritchard, Emma; Hayman, Jane; Gibbs, Anne; Hill, David J.

2005-01-01

The aim of this study is to determine what factors constitute a quality prosthesis and ascertain which factors affect prosthesis satisfaction. Sixty-four women who received full funding for their prosthesis and 38 women who received their hospital's usual funding were recruited. Women rated the information provided about breast prostheses very…

Penile prosthesis implant: scientific advances and technological innovations over the last four decades.

PubMed

Chung, Eric

2017-02-01

Despite introduction of oral phosphodiesterase type 5 inhibitors and intracavernosal vasoactive agents, penile prosthesis implant remains a relevant and desired option with sales of penile prostheses continue to stay high, as many men became refractory to medical therapy and/or seeking a more effective and permanent therapy. There are two types of penile prosthesis implants: inflatable and non-inflatable types, and the inflatable penile implants can be subdivided into single-, two- and three-piece devices. Non-inflatable penile prosthesis (non-IPP) may be referred to as semi-rigid rod or malleable prosthesis. IPP is considered a superior option to malleable prosthesis as it produces penile rigidity and flaccidity that closely replicates a normal penile erectile function. Since the introduction of IPP by Scott in 1973, surgical landscape for penile prosthesis implantation has changed dramatically. Advances in prosthesis design, device technologies and surgical techniques have made penile prosthesis implant a more natural, durable and reliable device. The following article reviews the scientific advances and technological innovation in modern penile prosthesis implants over the last four decades.

Penile prosthesis implant: scientific advances and technological innovations over the last four decades

PubMed Central

2017-01-01

Despite introduction of oral phosphodiesterase type 5 inhibitors and intracavernosal vasoactive agents, penile prosthesis implant remains a relevant and desired option with sales of penile prostheses continue to stay high, as many men became refractory to medical therapy and/or seeking a more effective and permanent therapy. There are two types of penile prosthesis implants: inflatable and non-inflatable types, and the inflatable penile implants can be subdivided into single-, two- and three-piece devices. Non-inflatable penile prosthesis (non-IPP) may be referred to as semi-rigid rod or malleable prosthesis. IPP is considered a superior option to malleable prosthesis as it produces penile rigidity and flaccidity that closely replicates a normal penile erectile function. Since the introduction of IPP by Scott in 1973, surgical landscape for penile prosthesis implantation has changed dramatically. Advances in prosthesis design, device technologies and surgical techniques have made penile prosthesis implant a more natural, durable and reliable device. The following article reviews the scientific advances and technological innovation in modern penile prosthesis implants over the last four decades. PMID:28217449

Use of Powered Prosthesis for Children with Upper Limb Deficiency at Hyogo Rehabilitation Center.

PubMed

Toda, Mitsunori; Chin, Takaaki; Shibata, Yaeko; Mizobe, Futoshi

2015-01-01

There has been no research investigating the use of powered prosthetic for children in Japan. To gain better insight into the state of powered prosthesis usage and identify a ratio of rejection among children. Subjects were 37 unilateral below elbow amputees between the ages of 0 and 16 at the time of their first experienced fitting with a powered prosthesis at our Center. The information was collected from medical records and through face-to-face interviews, and we examined rejection rate and the factors affecting the use of powered prosthesis. The rate of discontinuation was 21.6% as 8 of the 37 children stopped using powered prosthesis. All of them were fitted their prosthesis after 2 years of age, and they rejected prosthesis between 5 to 19 years. We found that the level of amputation had no influence on the use of a powered prosthesis. Children fitted before 2 years of age tend to accept their powered prosthesis than those fitted after 2 years. Multidisciprinary team approach, adequate rehabilitation, detailed follow-up and involvement of parents are quite important for introducing powered prosthesis for children.

Prosthetic management of mid-facial defect with magnet-retained silicone prosthesis.

PubMed

Buzayan, Muaiyed M

2014-02-01

Mid-facial defect is one of the most disfiguring and impairing defects. A design of prosthesis that is aesthetic and stable can be precious to a patient who has lost part of his face due to surgical excision. Prosthesis can restore the patients' self-esteem and confidence, which affects the patients and their life style. The aim of this case report is to describe a technique of mid-facial silicone prosthesis fabrication. To provide an aesthetic and stable facial prosthesis, the extra-oral prosthesis was fabricated using silicone material, while the intra-oral defect was restored with obturator prosthesis, and then both prostheses were connected and attached to each other using magnets. This clinical report describes the rehabilitation of a large mid-facial defect with a two-piece prosthesis. The silicone facial prosthesis was made hollow and lighter by using an acrylic framework. Two acrylic channels were included within the facial prosthesis to provide the patient with clean and patent airways. A sectional mid-facial prosthesis was made and retained in place by using magnets, which resulted in a significant improvement in the aesthetical and functional outcome without the need for plastic surgery. Silicone prostheses are reliable alternatives to surgery and should be considered in selected cases.

Wear of matrix overdenture attachments after one to eight years of clinical use.

PubMed

Fromentin, Olivier; Lassauzay, Claire; Nader, Samer Abi; Feine, Jocelyne; de Albuquerque, Rubens F

2012-03-01

Matrices of unsplinted attachment systems are generally reported to be the weak component of implant overdentures, often requiring frequent maintenance. Clinical wear results in reduced retention of the prosthesis, requiring activation or renewal of the matrix to restore the initial level of retention. The purpose of this retrospective study was to measure the wear of the matrix of a ball attachment after various periods of clinical wear. Seventy specimens of 3 groups of matrices of ball attachments that had been in use for mean periods of 12.3 months (1Y group, n=26), 39.0 months (3Y group, n=28) and 95.6 months (8Y group, n=16) were retrieved from 35 patients (2 specimens per patient) and measured on a coordinate measuring machine equipped with a touch trigger probe. Ten unused matrices were used as controls (CTRL group). The external and internal matrix diameters and deviations from circularity were measured. For the various time periods, the decreases in matrix thickness were calculated and compared with controls. Kruskal-Wallis 1-way ANOVA by ranks, followed by the Mann-Whitney post hoc tests, were conducted to test for differences in median values among groups (α =.05). For the internal upper diameter of the matrices tested, the Kruskal-Wallis and Mann-Whitney tests revealed significant differences for the 3 groups compared to the controls. For group 1Y, a significant difference (P<.001) of the internal upper diameter was found compared to the CTRL group. Compared to the controls, the nonparametric analyses for groups 3Y and 8Y showed significant differences for the internal upper diameter (P<.001) and deviations from circularity (P<.001). For groups 1Y, 3Y and 8Y, matrix thickness losses were 07, 47 and 70 μm, respectively. Within the limitations of this study, it was observed that one year of clinical wear had limited effect on the ball attachment matrices. Three to 8 years of clinical use resulted in a significant decrease of matrix thickness, especially at the tip of the retentive lamellae. Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

A Novel Thermal-activated Shape Memory Penile Prosthesis: Comparative Mechanical Testing.

PubMed

Le, Brian; McVary, Kevin; McKenna, Kevin; Colombo, Alberto

2017-01-01

To compare a novel nickel-titanium (Ni-Ti) shape memory alloy (SMA) penile prosthesis of our own design with commercially available prostheses using a format similar to mechanical testing done at major penile prosthesis manufacturers. We evaluated the mechanical parameters of commercially available penile prostheses and used this information to guide the development of the Ni-Ti-based physiological penile prosthesis that expands and becomes erect with a small amount of heat applied. A penile prosthesis consisting of an exoskeleton of temperature-tuned Nitinol was designed and prototyped. Mechanical testing was performed in a model of penile buckling, penile lateral deviation, and original penile shape recovery commonly used by penile prosthesis manufacturers for testing. Our SMA penile prosthesis demonstrated useful mechanical characteristics, including rigidity to buckling when activated similar to an inflatable penile prosthesis (2.62 kgf SMA vs 1.42 kgf inflatable penile prosthesis vs 6.45 kgf for a malleable prosthesis). The Ni-Ti also became more pliable when deactivated within acceptable mechanical ranges of existing devices. It could be repeatedly cycled and generate a restorative force to become erect. An SMA-based penile prosthesis represents a promising new technology in the treatment of erectile dysfunction. We demonstrated that an Ni-Ti-based prosthesis can produce the mechanical forces necessary for producing a simulated erection without the need for a pump or reservoir, comparable with existing prostheses. Copyright © 2016 Elsevier Inc. All rights reserved.

Penile Prosthesis Implantation in Patients with a History of Total Phallic Construction.

PubMed

Zuckerman, Jack M; Smentkowski, Katherine; Gilbert, David; Storme, Oscar; Jordan, Gerald; Virasoro, Ramon; Tonkin, Jeremy; McCammon, Kurt

2015-12-01

Outcomes following penile prosthesis implantation in patients with a history of total phallic construction are not well described. The aim of this study was to evaluate outcomes following neophallus penile prosthesis placement. Retrospective review penile prosthesis placement in patients with prior total phallic construction. GORE-TEX® (Gore Medical, Flagstaff, AZ) sleeve neotunica construction was utilized in all patients. Success defined as patient sexual activity with a functioning prosthesis. Thirty-one patients underwent neophallic prosthesis implantation at a mean 35.6 years of age. Prosthesis placement occurred at an average 56.3 months following phallic construction and follow-up was a mean of 59.7 months. Malleable prostheses were placed in 21 patients and inflatable in 10; implants were bilateral in 94%. Six percent experienced operative complications including a bladder injury (1) and phallic flap arterial injury (1). Postoperative complications occurred in 23% at a median 5.5 months following placement. Five prostheses were explanted secondary to infection or erosion and two additional required revisions. Of the explanted prosthesis two were later replaced without further complication. Eighty-one percent of patients were sexually active following prosthesis placement. Penile prosthesis placement is possible in patients with prior penile reconstruction/phallic construction. Although complications rates appear to be elevated in this population compared with historic controls of normal anatomic men, the majority of patients in this series were sexually active following prosthesis placement. This demonstrates the utility of prosthesis implantation in these difficult patients. © 2015 International Society for Sexual Medicine.

Multivariate prediction of upper limb prosthesis acceptance or rejection.

PubMed

Biddiss, Elaine A; Chau, Tom T

2008-07-01

To develop a model for prediction of upper limb prosthesis use or rejection. A questionnaire exploring factors in prosthesis acceptance was distributed internationally to individuals with upper limb absence through community-based support groups and rehabilitation hospitals. A total of 191 participants (59 prosthesis rejecters and 132 prosthesis wearers) were included in this study. A logistic regression model, a C5.0 decision tree, and a radial basis function neural network were developed and compared in terms of sensitivity (prediction of prosthesis rejecters), specificity (prediction of prosthesis wearers), and overall cross-validation accuracy. The logistic regression and neural network provided comparable overall accuracies of approximately 84 +/- 3%, specificity of 93%, and sensitivity of 61%. Fitting time-frame emerged as the predominant predictor. Individuals fitted within two years of birth (congenital) or six months of amputation (acquired) were 16 times more likely to continue prosthesis use. To increase rates of prosthesis acceptance, clinical directives should focus on timely, client-centred fitting strategies and the development of improved prostheses and healthcare for individuals with high-level or bilateral limb absence. Multivariate analyses are useful in determining the relative importance of the many factors involved in prosthesis acceptance and rejection.

Use of Powered Prosthesis for Children with Upper Limb Deficiency at Hyogo Rehabilitation Center

PubMed Central

Shibata, Yaeko; Mizobe, Futoshi

2015-01-01

Background There has been no research investigating the use of powered prosthetic for children in Japan. Objective To gain better insight into the state of powered prosthesis usage and identify a ratio of rejection among children. Methods Subjects were 37 unilateral below elbow amputees between the ages of 0 and 16 at the time of their first experienced fitting with a powered prosthesis at our Center. The information was collected from medical records and through face-to-face interviews, and we examined rejection rate and the factors affecting the use of powered prosthesis. Results The rate of discontinuation was 21.6% as 8 of the 37 children stopped using powered prosthesis. All of them were fitted their prosthesis after 2 years of age, and they rejected prosthesis between 5 to 19 years. We found that the level of amputation had no influence on the use of a powered prosthesis. Conclusions Children fitted before 2 years of age tend to accept their powered prosthesis than those fitted after 2 years. Multidisciprinary team approach, adequate rehabilitation, detailed follow-up and involvement of parents are quite important for introducing powered prosthesis for children. PMID:26125974

Laser-assisted fixation of a nitinol stapes prosthesis.

PubMed

Schrötzlmair, Florian; Suchan, Fabian; Pongratz, Thomas; Krause, Eike; Müller, Joachim; Sroka, Ronald

2018-02-01

Otosclerosis is an inner ear bone disease characterized by fixation of the stapes and consequently progressive hearing loss. One treatment option is the surgical replacement of the stapes by a prosthesis. When so called "smart materials" like nitinol are used, prosthesis fixation can be performed using a laser without manual crimping on the incus. However, specific laser-prosthesis interactions have not been described yet. The aim of the present study was to elucidate the thermo-mechanical properties of the NiTiBOND® prosthesis as a basis for handling instructions for laser-assisted prosthesis fixation. Closure of the NiTiBOND® prosthesis was induced ex vivo by either a diode laser emitting at λ = 940 nm or a CO 2 laser (λ = 10,600 nm). Total energy for closure was determined. Suitable laser parameters (pulse duration, power per pulse, distance between tip of the laser fiber and prosthesis) were assessed. Specific laser-prosthesis interactions were recorded. Especially the diode laser was found to be an appropriate energy source. A total energy deposit of 60 mJ by pulses in near contact application was found to be sufficient for prosthesis closure ex vivo. Energy should be transmitted through a laser fiber equipollent to the prosthesis band diameter. Specific deformation characteristics due to the zonal prosthesis composition have to be taken into account. NiTiBOND® stapes prosthesis can be closed by very little energy when appropriate energy sources like diode lasers are used, suggesting a relatively safe application in vivo. Lasers Surg. Med. 50:153-157, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Predictors of Receiving a Prosthesis for Adults With Above-Knee Amputations in a Well-Defined Population.

PubMed

Mundell, Benjamin F; Kremers, Hilal Maradit; Visscher, Sue; Hoppe, Kurtis M; Kaufman, Kenton R

2016-08-01

Prior studies have identified age as a factor in determining an individual's likelihood of receiving a prosthesis following a lower limb amputation. These studies are limited to specific subsets of the general population and are unable to account for preamputation characteristics within their study populations. Our study seeks to determine the effect of preamputation characteristics on the probability of receiving a prosthesis for the general population in the United States. To identify preamputation characteristics that predict of the likelihood of receiving a prosthesis following an above-knee amputation. A retrospective, population-based cohort study. Olmsted County, Minnesota (2010 population: 144,248). Individuals (n = 93) over the age of 18 years who underwent an above-knee amputation, that is, knee disarticulation or transfemoral amputation, while residing in Olmsted County, MN, between 1987 and 2013. Characteristics affecting the receipt of a prosthesis were analyzed using a logistic regression and a random forest algorithm for classification trees. Preamputation characteristics included age, gender, amputation etiology, year of amputation, mobility, cognitive ability, comorbidities, and time between surgery and the prosthesis decision. The association of preamputation characteristics with the receipt of a prosthesis following an above-knee amputation. Twenty-four of the participants received a prosthesis. The odds of receiving a prosthesis were almost 30 times higher in those able to walk independently prior to an amputation relative to those who could not walk independently. A 10-year increase in age was associated with a 53.8% decrease in the likelihood of being fit for a prosthesis (odds ratio = 0.462, P =.030). Time elapsed between surgery and the prosthesis decision was associated with a rise in probability of receiving a prosthesis for the first 3 months in the random forest algorithm. No other observed characteristics were associated with receipt of a prosthesis. The association of preamputation mobility and age with the likelihood of being fit for a prosthesis is well understood. The effect of age, after controlling for confounders, still persists and is associated with the likelihood of being fit for a prosthesis. Copyright © 2016 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Robotic lower limb prosthesis design through simultaneous computer optimizations of human and prosthesis costs

NASA Astrophysics Data System (ADS)

Handford, Matthew L.; Srinivasan, Manoj

2016-02-01

Robotic lower limb prostheses can improve the quality of life for amputees. Development of such devices, currently dominated by long prototyping periods, could be sped up by predictive simulations. In contrast to some amputee simulations which track experimentally determined non-amputee walking kinematics, here, we explicitly model the human-prosthesis interaction to produce a prediction of the user’s walking kinematics. We obtain simulations of an amputee using an ankle-foot prosthesis by simultaneously optimizing human movements and prosthesis actuation, minimizing a weighted sum of human metabolic and prosthesis costs. The resulting Pareto optimal solutions predict that increasing prosthesis energy cost, decreasing prosthesis mass, and allowing asymmetric gaits all decrease human metabolic rate for a given speed and alter human kinematics. The metabolic rates increase monotonically with speed. Remarkably, by performing an analogous optimization for a non-amputee human, we predict that an amputee walking with an appropriately optimized robotic prosthesis can have a lower metabolic cost - even lower than assuming that the non-amputee’s ankle torques are cost-free.

Preparation for the Implantation of an Intracortical Visual Prosthesis in a Human

DTIC Science & Technology

2014-10-01

Intracortical Visual Prosthesis in a Human PRINCIPAL INVESTIGATOR: Philip R Troyk, PhD... Prosthesis in a Human 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-12-1-0394 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Philip R Troyk...visual prosthesis (ICVP) for testing in a human. No human trial testing of the prosthesis will occur under the funded work. Preparatory tasks include

Long-term role of external breast prostheses after total mastectomy.

PubMed

Glaus, Simone W; Carlson, Grant W

2009-01-01

After total mastectomy, many women choose to wear external breast prosthesis rather than undergo breast reconstruction. The purpose of this study was to evaluate long-term satisfaction among external breast prosthesis wearers and the impact of satisfaction on prosthesis use. A questionnaire was designed to assess demographic information, prosthesis information provision, prosthesis use, and satisfaction with prosthesis. Fifty-nine women who had undergone total mastectomy without breast reconstruction completed the questionnaire. The majority of women (68%) were at least 5 years out from mastectomy. Approximately half (49%) of the women had received information about breast prostheses prior to mastectomy; 29% received information from the surgeon performing the operation. Frequent and prolonged prosthesis use was prevalent with 64% of participants reporting prosthesis use all the time, 6-7 days/week. Participants showed high rates (83%) of overall satisfaction. However, women who wore their prosthesis out in public only were less satisfied than more frequent wearers (50% versus 89%, chi(2) = 8.83, d.f. = 1, alpha = 0.05). Satisfaction increased over time, as women who were greater than 5 years out from mastectomy were more satisfied than women less that 5 years post-mastectomy (90% versus 67%, chi(2) = 4.43, d.f. = 1, alpha = 0.05). The vast majority of women are satisfied with their external breast prosthesis several years after mastectomy. Most women used their prosthesis all the time and overall satisfaction contributed to higher levels of prosthesis use. Given the long-term importance of external breast prostheses for women who have undergone mastectomy, a greater effort to inform patients about external breast prostheses prior to surgery is needed.

Do CTA measurements of annular diameter, perimeter and area result in different TAVI prosthesis sizes?

PubMed

Horehledova, Barbora; Mihl, Casper; Hendriks, Babs M F; Eijsvoogel, Nienke G; Vainer, Jindrich; Veenstra, Leo F; Wildberger, Joachim E; Das, Marco

2018-06-16

Incorrect prosthesis size has direct impact on patient outcome after transcatheter aortic valve implantation (TAVI) procedure. Currently, annular diameter, area or perimeter may be used for prosthesis size selection. The aim was to evaluate whether the use different annular dimensions would result in the selection of different prosthesis sizes, when assessed in the same TAVI-candidate during the same phase of a cardiac cycle. Fifty consecutive TAVI-candidates underwent retrospectively ECG-gated computed tomography angiography (CTA). Aortic root dimensions were assessed in the 20% phase of the R-R interval. Annular short diameter, perimeter and area were used to select the prosthesis size, based on the industry recommendations for a self-expandable (Medtronic CoreValve; MCV) and balloon-expandable (Edwards Sapien XT Valve; ESV) valve. Complete agreement on selected prosthesis size amongst all three annular dimensions was observed in 62% (31/50; ESV) and 30% (15/50; MCV). Short aortic annulus measurement resulted in a smaller prosthesis size in 20% (10/50; ESV) and in 60% of cases (30/50; MCV) compared to the size suggested by both annular perimeter and area. In 18% (9/50; ESV) and 10% of cases (5/50; MCV) a larger prosthesis would have been selected based on annular perimeter compared to annular diameter and area. Prosthesis size derived from area was always in agreement with at least one other parameter in all cases. Aortic annulus area appears to be the most robust parameter for TAVI-prosthesis size selection, regardless of the specific prosthesis size. Short aortic annulus diameter may underestimate the prosthesis size, while use of annular perimeter may lead to size overestimation in some cases.

Permanent Quadriplegia Following Replacement of Voice Prosthesis.

PubMed

Ozturk, Kayhan; Erdur, Omer; Kibar, Ertugrul

2016-11-01

The authors presented a patient with quadriplegia caused by cervical spine abscess following voice prosthesis replacement. The authors present the first reported permanent quadriplegia patient caused by voice prosthesis replacement. The authors wanted to emphasize that life-threatening complications may be faced during the replacement of voice prosthesis. Care should be taken during the replacement of voice prosthesis and if some problems have been faced during the procedure patients must be followed closely.

Preparation for the Implantation of an Intracortical Visual Prosthesis in a Human

DTIC Science & Technology

2013-10-01

Intracortical Visual Prosthesis in a Human PRINCIPAL INVESTIGATOR: Philip R Troyk, PhD... Prosthesis in a Human 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-12-1-0394 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Philip R Troyk, PhD...to prepare an intracortical visual prosthesis (ICVP) for testing in a human. No human trial testing of the prosthesis will occur under the funded

SHABERTH - ANALYSIS OF A SHAFT BEARING SYSTEM (CRAY VERSION)

NASA Technical Reports Server (NTRS)

Coe, H. H.

1994-01-01

The SHABERTH computer program was developed to predict operating characteristics of bearings in a multibearing load support system. Lubricated and non-lubricated bearings can be modeled. SHABERTH calculates the loads, torques, temperatures, and fatigue life for ball and/or roller bearings on a single shaft. The program also allows for an analysis of the system reaction to the termination of lubricant supply to the bearings and other lubricated mechanical elements. SHABERTH has proven to be a valuable tool in the design and analysis of shaft bearing systems. The SHABERTH program is structured with four nested calculation schemes. The thermal scheme performs steady state and transient temperature calculations which predict system temperatures for a given operating state. The bearing dimensional equilibrium scheme uses the bearing temperatures, predicted by the temperature mapping subprograms, and the rolling element raceway load distribution, predicted by the bearing subprogram, to calculate bearing diametral clearance for a given operating state. The shaft-bearing system load equilibrium scheme calculates bearing inner ring positions relative to the respective outer rings such that the external loading applied to the shaft is brought into equilibrium by the rolling element loads which develop at each bearing inner ring for a given operating state. The bearing rolling element and cage load equilibrium scheme calculates the rolling element and cage equilibrium positions and rotational speeds based on the relative inner-outer ring positions, inertia effects, and friction conditions. The ball bearing subprograms in the current SHABERTH program have several model enhancements over similar programs. These enhancements include an elastohydrodynamic (EHD) film thickness model that accounts for thermal heating in the contact area and lubricant film starvation; a new model for traction combined with an asperity load sharing model; a model for the hydrodynamic rolling and shear forces in the inlet zone of lubricated contacts, which accounts for the degree of lubricant film starvation; modeling normal and friction forces between a ball and a cage pocket, which account for the transition between the hydrodynamic and elastohydrodynamic regimes of lubrication; and a model of the effect on fatigue life of the ratio of the EHD plateau film thickness to the composite surface roughness. SHABERTH is intended to be as general as possible. The models in SHABERTH allow for the complete mathematical simulation of real physical systems. Systems are limited to a maximum of five bearings supporting the shaft, a maximum of thirty rolling elements per bearing, and a maximum of one hundred temperature nodes. The SHABERTH program structure is modular and has been designed to permit refinement and replacement of various component models as the need and opportunities develop. A preprocessor is included in the IBM PC version of SHABERTH to provide a user friendly means of developing SHABERTH models and executing the resulting code. The preprocessor allows the user to create and modify data files with minimal effort and a reduced chance for errors. Data is utilized as it is entered; the preprocessor then decides what additional data is required to complete the model. Only this required information is requested. The preprocessor can accommodate data input for any SHABERTH compatible shaft bearing system model. The system may include ball bearings, roller bearings, and/or tapered roller bearings. SHABERTH is written in FORTRAN 77, and two machine versions are available from COSMIC. The CRAY version (LEW-14860) has a RAM requirement of 176K of 64 bit words. The IBM PC version (MFS-28818) is written for IBM PC series and compatible computers running MS-DOS, and includes a sample MS-DOS executable. For execution, the PC version requires at least 1Mb of RAM and an 80386 or 486 processor machine with an 80x87 math co-processor. The standard distribution medium for the IBM PC version is a set of two 5.25 inch 360K MS-DOS format diskettes. The contents of the diskettes are compressed using the PKWARE archiving tools. The utility to unarchive the files, PKUNZIP.EXE, is included. The standard distribution medium for the CRAY version is also a 5.25 inch 360K MS-DOS format diskette, but alternate distribution media and formats are available upon request. The original version of SHABERTH was developed in FORTRAN IV at Lewis Research Center for use on a UNIVAC 1100 series computer. The Cray version was released in 1988, and was updated in 1990 to incorporate fluid rheological data for Rocket Propellant 1 (RP-1), thereby allowing the analysis of bearings lubricated with RP-1. The PC version is a port of the 1990 CRAY version and was developed in 1992 by SRS Technologies under contract to NASA Marshall Space Flight Center.

Intermittent, noncyclic dysfunction of a mechanical aortic prosthesis by pannus formation.

PubMed

Giroux, Sylvie K; Labinaz, Marino X; Grisoli, Dominique; Klug, Andrew P; Veinot, John P; Burwash, Ian G

2010-01-01

Mechanical aortic prosthesis dysfunction can result from thrombosis or pannus formation. Pannus formation usually restricts systolic excursion of the occluding disk, resulting in progressive stenosis of the aortic prosthesis. Intermittent dysfunction of a mechanical aortic prosthesis is usually ascribed to thrombus formation. We describe an unusual case of intermittent, noncyclic dysfunction of a mechanical aortic prosthesis due to pannus formation in the absence of systolic restriction of disk excursion that presented with intermittent massive aortic regurgitation, severe ischemia, and shock. Pannus formation should be considered as a potential cause of acute intermittent severe aortic regurgitation in a patient with a mechanical aortic prosthesis.

BIORESORBABLE POLYMERIC MENISCAL PROSTHESIS: STUDY IN RABBITS

PubMed Central

Cardoso, Tulio Pereira; de Rezende Duek, Eliana Aparecida; Amatuzzi, Marco Martins; Caetano, Edie Benedito

2015-01-01

Objective: To induce growth of a neomeniscus into the pores of a prosthesis in order to protect the knee joint cartilage. Methods: 70 knees of 35 New Zealand rabbits were operated. The rabbits were five to seven months old, weighed 2 to 3.8 kilograms, and 22 were male and 13 were female. Each animal underwent medial meniscectomy in both knees during a single operation. A bioabsorbable polymeric meniscal prosthesis composed of 70% polydioxanone and 30% L-lactic acid polymer was implanted in one side. The animals were sacrificed after different postoperative time intervals. The femoral condyles and neomeniscus were subjected to histological analysis. Histograms were used to measure the degradation and absorption of the prosthesis, the growth of meniscal tissue in the prosthesis and the degree of degradation of the femoral condyle joint cartilage. Results: The data obtained showed that tissue growth histologically resembling a normal meniscus occurred, with gradual absorption of the prosthesis, and the percentages of chondrocytes on the control side and prosthesis side. Conclusion: Tissue growth into the prosthesis pores that histologically resembled the normal rabbit meniscus was observed. The joint cartilage of the femoral condyles on the prosthesis side presented greater numbers of chondrocytes in all its layers. PMID:27022549

Duocentric® reversed shoulder prosthesis and Personal Fit® templates: innovative strategies to optimize prosthesis positioning and prevent scapular notching.

PubMed

Trouilloud, P; Gonzalvez, M; Martz, P; Charles, H; Handelberg, F; Nyffeler, R W; Baulot, E

2014-05-01

We describe our experience with a new system of patient-specific template called Personal Fit(®), which is unique in shoulder surgery and used in combination with Duocentric(®) prosthesis. The reverse prosthesis's concept is the invention of Paul Grammont, developed with Grammont's team of Dijon University as from 1981, which led to the first reversed total shoulder prosthesis called Trumpet in 1985. The Duocentric(®) prosthesis developed in 2001 is the third-generation prosthesis, coming from the Trumpet and the second-generation prosthesis Delta(®) (DePuy). This prosthesis provides a novel solution to the notching problem with an inferior overhang integrated onto the glenoid baseplate. Personal Fit(®) system is based on reconstructing the shoulder joint bones in three dimensions using CT scan data, placing a landmark on the scapula and locating points on the glenoid and humerus. That will be used as a reference for the patient-specific templates. We study the glenoid position planned with Personal Fit(®) software relative to native glenoid position in 30 cases. On average, the difference between the planned retroversion (or anteversion in one case) and native retroversion was 8.6°.

21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device intended...

21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device intended...

21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device intended...

21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device intended...

21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device intended...

21 CFR 872.3940 - Total temporomandibular joint prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Total temporomandibular joint prosthesis. 872.3940... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3940 Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is intended to be...

21 CFR 872.3940 - Total temporomandibular joint prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Total temporomandibular joint prosthesis. 872.3940... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3940 Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is intended to be...

MPR-CT Imaging for Stapes Prosthesis: Accuracy and Clinical Significance.

PubMed

Fang, Yanqing; Wang, Bing; Galvin, John J; Tao, Duoduo; Deng, Rui; Ou, Xiong; Liu, Yangwenyi; Dai, Peidong; Sha, Yan; Zhang, Tianyu; Chen, Bing

2016-04-01

The aims of this article are: 1) to re-evaluate the accuracy of multiple planar reconstruction computed tomography (MPR-CT) imaging on stapes-prosthesis parameters, and 2) to clarify possible relationships between prosthesis intravestibular depth and postoperative hearing outcomes. Seventy patients (46 women and 24 men; 32 right and 38 left sides) with the mean age of 40 years (range, 19-62 yr) with clinical otosclerosis. All patients underwent stapedotomy and were implanted with the same type of titanium piston prosthesis by the same surgeon. Postoperative MPR-CTs were obtained at patients' follow-up visits. The length and intravestibular depth of the stapes prosthesis (including absolute and relative depth) were calculated from the MPR-CT imaging. Relationships between the intravestibular depth of the prosthesis and hearing outcomes (pre- and postoperative audiograms) were analyzed using Spearman correlation analyses. The length of the prosthesis was overestimated by 1.8% (0.1 mm) by the MPR-CT imaging. Axial and coronal measurements were significantly correlated (p < 0.05). There was great intersubject variability in hearing outcomes differed insignificantly, regardless of intravestibular depth within the security range. No relationships were found between the intravestibular depth of the stapes prosthesis, as measured with MPR-CT, and postoperative hearing results. MPR-CT can provide an accurate estimation of stapes prosthesis parameters. However, the prosthesis intravestibular depth did not seem to affect postoperative hearing outcomes.

An innovative method of ocular prosthesis fabrication by bio-CAD and rapid 3-D printing technology: A pilot study.

PubMed

Alam, Md Shahid; Sugavaneswaran, M; Arumaikkannu, G; Mukherjee, Bipasha

2017-08-01

Ocular prosthesis is either a readymade stock shell or custom made prosthesis (CMP). Presently, there is no other technology available, which is either superior or even comparable to the conventional CMP. The present study was designed to fabricate ocular prosthesis using computer aided design (CAD) and rapid manufacturing (RM) technology and to compare it with custom made prosthesis (CMP). The ocular prosthesis prepared by CAD was compared with conventional CMP in terms of time taken for fabrication, weight, cosmesis, comfort, and motility. Two eyes of two patients were included. Computerized tomography scan of wax model of socket was converted into three dimensional format using Materialize Interactive Medical Image Control System (MIMICS)software and further refined. This was given as an input to rapid manufacturing machine (Polyjet 3-D printer). The final painting on prototype was done by an ocularist. The average effective time required for fabrication of CAD prosthesis was 2.5 hours; and weight 2.9 grams. The same for CMP were 10 hours; and 4.4 grams. CAD prosthesis was more comfortable for both the patients. The study demonstrates the first ever attempt of fabricating a complete ocular prosthesis using CAD and rapid manufacturing and comparing it with conventional CMP. This prosthesis takes lesser time for fabrication, and is more comfortable. Studies with larger sample size will be required to further validate this technique.

Stress Distribution in Splinted and Unsplinted Implant-Supported Maxillary Overdentures: A 3D Finite Element Analysis.

PubMed

Geramy, Allahyar; Habibzadeh, Sareh

2018-02-01

This study was accomplished to assess the biomechanical state of splinting in implant-supported maxillary overdentures. Two models of maxillary overdentures were designed in SolidWorks 2011. The first model included 4 separate implants and ball abutments, whereas the second one included 4 splinted implants connected with a bar. Evaluation was performed in ANSYS Workbench software with 200 N load applied at the molar-premolar region, bilaterally. The maximum equivalent stress and strain (von Mises) was recorded and analyzed along a path between the implants in the crestal bone and the prosthetic attachments. First model presented higher values of strain in prosthetic attachment and higher values of von Mises stress in crestal bone. The second model presented higher stress concentration in the gingival tissue of premolar area (near the bar), whereas the peak stress values were reported within the most distal part of the soft tissue support of the prosthesis in the first model (unsplinted). Splinting maxillary overdentures implants is associated with significant lower stress levels in the surrounding bone tissue.

Artificial limb representation in amputees

PubMed Central

van den Heiligenberg, Fiona M Z; Orlov, Tanya; Macdonald, Scott N; Duff, Eugene P; Henderson Slater, David; Beckmann, Christian F; Johansen-Berg, Heidi; Culham, Jody C; Makin, Tamar R

2018-01-01

Abstract The human brain contains multiple hand-selective areas, in both the sensorimotor and visual systems. Could our brain repurpose neural resources, originally developed for supporting hand function, to represent and control artificial limbs? We studied individuals with congenital or acquired hand-loss (hereafter one-handers) using functional MRI. We show that the more one-handers use an artificial limb (prosthesis) in their everyday life, the stronger visual hand-selective areas in the lateral occipitotemporal cortex respond to prosthesis images. This was found even when one-handers were presented with images of active prostheses that share the functionality of the hand but not necessarily its visual features (e.g. a ‘hook’ prosthesis). Further, we show that daily prosthesis usage determines large-scale inter-network communication across hand-selective areas. This was demonstrated by increased resting state functional connectivity between visual and sensorimotor hand-selective areas, proportional to the intensiveness of everyday prosthesis usage. Further analysis revealed a 3-fold coupling between prosthesis activity, visuomotor connectivity and usage, suggesting a possible role for the motor system in shaping use-dependent representation in visual hand-selective areas, and/or vice versa. Moreover, able-bodied control participants who routinely observe prosthesis usage (albeit less intensively than the prosthesis users) showed significantly weaker associations between degree of prosthesis observation and visual cortex activity or connectivity. Together, our findings suggest that altered daily motor behaviour facilitates prosthesis-related visual processing and shapes communication across hand-selective areas. This neurophysiological substrate for prosthesis embodiment may inspire rehabilitation approaches to improve usage of existing substitutionary devices and aid implementation of future assistive and augmentative technologies. PMID:29534154

Artificial limb representation in amputees.

PubMed

van den Heiligenberg, Fiona M Z; Orlov, Tanya; Macdonald, Scott N; Duff, Eugene P; Henderson Slater, David; Beckmann, Christian F; Johansen-Berg, Heidi; Culham, Jody C; Makin, Tamar R

2018-05-01

The human brain contains multiple hand-selective areas, in both the sensorimotor and visual systems. Could our brain repurpose neural resources, originally developed for supporting hand function, to represent and control artificial limbs? We studied individuals with congenital or acquired hand-loss (hereafter one-handers) using functional MRI. We show that the more one-handers use an artificial limb (prosthesis) in their everyday life, the stronger visual hand-selective areas in the lateral occipitotemporal cortex respond to prosthesis images. This was found even when one-handers were presented with images of active prostheses that share the functionality of the hand but not necessarily its visual features (e.g. a 'hook' prosthesis). Further, we show that daily prosthesis usage determines large-scale inter-network communication across hand-selective areas. This was demonstrated by increased resting state functional connectivity between visual and sensorimotor hand-selective areas, proportional to the intensiveness of everyday prosthesis usage. Further analysis revealed a 3-fold coupling between prosthesis activity, visuomotor connectivity and usage, suggesting a possible role for the motor system in shaping use-dependent representation in visual hand-selective areas, and/or vice versa. Moreover, able-bodied control participants who routinely observe prosthesis usage (albeit less intensively than the prosthesis users) showed significantly weaker associations between degree of prosthesis observation and visual cortex activity or connectivity. Together, our findings suggest that altered daily motor behaviour facilitates prosthesis-related visual processing and shapes communication across hand-selective areas. This neurophysiological substrate for prosthesis embodiment may inspire rehabilitation approaches to improve usage of existing substitutionary devices and aid implementation of future assistive and augmentative technologies.

21 CFR 888.3790 - Wrist joint metal constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wrist joint metal constrained cemented prosthesis... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3790 Wrist joint metal constrained cemented prosthesis. (a) Identification. A wrist joint metal constrained cemented prosthesis is a...

21 CFR 888.3790 - Wrist joint metal constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Wrist joint metal constrained cemented prosthesis... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3790 Wrist joint metal constrained cemented prosthesis. (a) Identification. A wrist joint metal constrained cemented prosthesis is a...

21 CFR 888.3720 - Toe joint polymer constrained prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Toe joint polymer constrained prosthesis. 888.3720... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3720 Toe joint polymer constrained prosthesis. (a) Identification. A toe joint polymer constrained prosthesis is a device made of silicone...

21 CFR 888.3780 - Wrist joint polymer constrained prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wrist joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3780 Wrist joint polymer constrained prosthesis. (a) Identification. A wrist joint polymer constrained prosthesis is a device made of...

21 CFR 888.3720 - Toe joint polymer constrained prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Toe joint polymer constrained prosthesis. 888.3720... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3720 Toe joint polymer constrained prosthesis. (a) Identification. A toe joint polymer constrained prosthesis is a device made of silicone...

21 CFR 888.3780 - Wrist joint polymer constrained prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Wrist joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3780 Wrist joint polymer constrained prosthesis. (a) Identification. A wrist joint polymer constrained prosthesis is a device made of...

21 CFR 888.3780 - Wrist joint polymer constrained prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Wrist joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3780 Wrist joint polymer constrained prosthesis. (a) Identification. A wrist joint polymer constrained prosthesis is a device made of...

21 CFR 888.3780 - Wrist joint polymer constrained prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Wrist joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3780 Wrist joint polymer constrained prosthesis. (a) Identification. A wrist joint polymer constrained prosthesis is a device made of...

21 CFR 888.3720 - Toe joint polymer constrained prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Toe joint polymer constrained prosthesis. 888.3720... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3720 Toe joint polymer constrained prosthesis. (a) Identification. A toe joint polymer constrained prosthesis is a device made of silicone...

21 CFR 888.3720 - Toe joint polymer constrained prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Toe joint polymer constrained prosthesis. 888.3720... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3720 Toe joint polymer constrained prosthesis. (a) Identification. A toe joint polymer constrained prosthesis is a device made of silicone...

21 CFR 888.3780 - Wrist joint polymer constrained prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Wrist joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3780 Wrist joint polymer constrained prosthesis. (a) Identification. A wrist joint polymer constrained prosthesis is a device made of...

21 CFR 888.3720 - Toe joint polymer constrained prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Toe joint polymer constrained prosthesis. 888.3720... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3720 Toe joint polymer constrained prosthesis. (a) Identification. A toe joint polymer constrained prosthesis is a device made of silicone...

21 CFR 872.3960 - Mandibular condyle prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3960 Mandibular condyle prosthesis. (a) Identification. A mandibular condyle prosthesis is a device that is intended to be implanted in the human jaw to... requirement for premarket approval for any mandibular condyle prosthesis intended to be implanted in the human...

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Passive tendon prosthesis. 888.3025 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or a...

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Passive tendon prosthesis. 888.3025 Section 888...) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a) Identification. A passive tendon prosthesis is a device intended to be implanted made of silicon elastomer or a...

Fluid mechanics of heart valves.

PubMed

Yoganathan, Ajit P; He, Zhaoming; Casey Jones, S

2004-01-01

Valvular heart disease is a life-threatening disease that afflicts millions of people worldwide and leads to approximately 250,000 valve repairs and/or replacements each year. Malfunction of a native valve impairs its efficient fluid mechanic/hemodynamic performance. Artificial heart valves have been used since 1960 to replace diseased native valves and have saved millions of lives. Unfortunately, despite four decades of use, these devices are less than ideal and lead to many complications. Many of these complications/problems are directly related to the fluid mechanics associated with the various mechanical and bioprosthetic valve designs. This review focuses on the state-of-the-art experimental and computational fluid mechanics of native and prosthetic heart valves in current clinical use. The fluid dynamic performance characteristics of caged-ball, tilting-disc, bileaflet mechanical valves and porcine and pericardial stented and nonstented bioprostheic valves are reviewed. Other issues related to heart valve performance, such as biomaterials, solid mechanics, tissue mechanics, and durability, are not addressed in this review.

Rocketdyne LOX bearing tester program

NASA Technical Reports Server (NTRS)

Keba, J. E.; Beatty, R. F.

1988-01-01

The cause, or causes, for the Space Shuttle Main Engine ball wear were unknown, however, several mechanisms were suspected. Two testers were designed and built for operation in liquid oxygen to empirically gain insight into the problems and iterate solutions in a timely and cost efficient manner independent of engine testing. Schedules and test plans were developed that defined a test matrix consisting of parametric variations of loading, cooling or vapor margin, cage lubrication, material, and geometry studies. Initial test results indicated that the low pressure pump thrust bearing surface distress is a function of high axial load. Initial high pressure turbopump bearing tests produced the wear phenomenon observed in the turbopump and identified an inadequate vapor margin problem and a coolant flowrate sensitivity issue. These tests provided calibration data of analytical model predictions to give high confidence in the positive impact of future turbopump design modification for flight. Various modifications will be evaluated in these testers, since similar turbopump conditions can be produced and the benefit of the modification will be quantified in measured wear life comparisons.

Radiofrequency-sputtered coatings for lubrication system components and other complex surfaces

NASA Technical Reports Server (NTRS)

Spalvins, T.

1972-01-01

Irregularly shaped surfaces, such as lubrication system components (ball bearings, seals, gears, etc.), can be coated on all surfaces, including irregular shapes, when radiofrequency sputtering is used. When the specimen is properly located with respect to the sputtering target, the sputtered material covers the entire surface of the object irrespective of its geometrical configuration. An adherent, dense film is formed. The film thickness varies from 20 to 50 percent on, for example, a hearing cage or race depending on its geometry. When sputtered solid film lubricants such as molybdenum disulfide are used, a film thickness only of the order of 10 to the minus 7th power m (thousands of angstroms) is required at the contacting areas. It is only essential to determine the required film thickness at the critical areas in need of lubrication. The sections outside the areas to be lubricated fall within the thickness deviation range of 20 to 50 percent, which still constitutes a negligible change respect to tolerance requirements.

The interactions of high-energy, highly-charged ions with fullerenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ali, R.; Berry, H.G.; Cheng, S.

1996-03-01

In 1985, Robert Curl and Richard Smalley discovered a new form of carbon, the fullerene, C{sub 60}, which consists of 60 carbon atoms in a closed cage resembling a soccer ball. In 1990, Kritschmer et al. were able to make macroscopic quantities of fullerenes. This has generated intense activity to study the properties of fullerenes. One area of research involves collisions between fullerenes and atoms, ions or electrons. In this paper we describe experiments involving interactions between fullerenes and highly charged ions in which the center-of-mass energies exceed those used in other work by several orders of magnitude. The highmore » values of projectile velocity and charge state result in excitation and decay processes differing significantly from those seen in studies 3 at lower energies. Our results are discussed in terms of theoretical models analogous to those used in nuclear physics and this provides an interesting demonstration of the unity of physics.« less

Tribological coatings for complex mechanical elements produced by supersonic cluster beam deposition of metal dichalcogenide nanoparticles

NASA Astrophysics Data System (ADS)

Piazzoni, C.; Buttery, M.; Hampson, M. R.; Roberts, E. W.; Ducati, C.; Lenardi, C.; Cavaliere, F.; Piseri, P.; Milani, P.

2015-07-01

Fullerene-like MoS2 and WS2 nanoparticles can be used as building blocks for the fabrication of fluid and solid lubricants. Metal dichalcogenide films have a very low friction coefficient in vacuum, therefore they have mostly been used as solid lubricants in space and vacuum applications. Unfortunately, their use is significantly hampered by the fact that in the presence of humidity, oxygen and moisture, the low-friction properties of these materials rapidly degrade due to oxidation. The use of closed-cage MoS2 and WS2 nanoparticles may eliminate this problem, although the fabrication of lubricant thin films starting from dichalcogenide nanoparticles is, to date, a difficult task. Here we demonstrate the use of supersonic cluster beam deposition for the coating of complex mechanical elements (angular contact ball bearings) with nanostructured MoS2 and WS2 thin films. We report structural and tribological characterization of the coatings in view of the optimization of tribological performances for aerospace applications.

Reverse Shoulder Arthroplasty Prosthesis Design Classification System.

PubMed

Routman, Howard D; Flurin, Pierre-Henri; Wright, Thomas W; Zuckerman, Joseph D; Hamilton, Matthew A; Roche, Christopher P

2015-12-01

Multiple different reverse total shoulder arthroplasty (rTSA) prosthesis designs are available in the global marketplace for surgeons to perform this growing procedure. Subtle differences in rTSA prosthesis design parameters have been shown to have significant biomechanical impact and clinical consequences. We propose an rTSA prosthesis design classification system to objectively identify and categorize different designs based upon their specific glenoid and humeral prosthetic characteristics for the purpose of standardizing nomenclature that will help the orthopaedic surgeon determine which combination of design configurations best suit a given clinical scenario. The impact of each prosthesis classification type on shoulder muscle length and deltoid wrapping are also described to illustrate how each prosthesis classification type impacts these biomechanical parameters.

Mechanical ball-milling preparation of fullerene/cobalt core/shell nanocomposites with high electrochemical hydrogen storage ability.

PubMed

Bao, Di; Gao, Peng; Shen, Xiande; Chang, Cheng; Wang, Longqiang; Wang, Ying; Chen, Yujin; Zhou, Xiaoming; Sun, Shuchao; Li, Guobao; Yang, Piaoping

2014-02-26

The design and synthesis of new hydrogen storage nanomaterials with high capacity at low cost is extremely desirable but remains challenging for today's development of hydrogen economy. Because of the special honeycomb structures and excellent physical and chemical characters, fullerenes have been extensively considered as ideal materials for hydrogen storage materials. To take the most advantage of its distinctive symmetrical carbon cage structure, we have uniformly coated C60's surface with metal cobalt in nanoscale to form a core/shell structure through a simple ball-milling process in this work. The X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectra, high-solution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrometry (EDX) elemental mappings, and X-ray photoelectron spectroscopy (XPS) measurements have been conducted to evaluate the size and the composition of the composites. In addition, the blue shift of C60 pentagonal pinch mode demonstrates the formation of Co-C chemical bond, and which enhances the stability of the as-obtained nanocomposites. And their electrochemical experimental results demonstrate that the as-obtained C60/Co composites have excellent electrochemical hydrogen storage cycle reversibility and considerably high hydrogen storage capacities of 907 mAh/g (3.32 wt % hydrogen) under room temperature and ambient pressure, which is very close to the theoretical hydrogen storage capacities of individual metal Co (3.33 wt % hydrogen). Furthermore, their hydrogen storage processes and the mechanism have also been investigated, in which the quasi-reversible C60/Co↔C60/Co-Hx reaction is the dominant cycle process.

Development and clinical application of a new testicular prosthesis

PubMed Central

Ning, Ye; Cai, Zhikang; Chen, Huixing; Ping, Ping; Li, Peng; Wang, Zhong; Li, Zheng

2011-01-01

A new type of testicular prosthesis made of silastic with an elliptical shape to mimic a normal testis was developed by our team and submitted for patenting in China. The prosthesis was produced in different sizes to imitate the normal testis of the patient. To investigate the effects and safety of the testicular prosthesis, 20 patients receiving testicular prosthesis implantation were recruited for this study. Follow-up after 6 months revealed no complications in the patients. All the patients answered that they were satisfied with their body image and the position of the implants, 19 patients were satisfied with the size and 16 patients were satisfied with the weight. These results show that the testicular prosthesis used in this study can meet patient's expectations. Patients undergoing orchiectomy should be offered the option to receive a testicular prosthesis implantation. The dimensions and weight of the available prosthetic implants should be further addressed to improve patient satisfaction. PMID:21927041

Manufacturer-provided effective orifice area index charts and the prevention of prosthesis-patient mismatch.

PubMed

House, Chad M; Nelson, William B; Kroshus, Timothy J; Dahiya, Ranjan; Pibarot, Philippe

2012-01-01

Prosthesis-patient mismatch (PPM) occurs when an implanted prosthesis is too small relative to the patient's body surface area (BSA). However, mismatch can often be prevented by indexing the expected effective orifice area (EOA) of a prosthesis to the patient's BSA and then selecting the largest implantable prosthesis to avoid mismatch. Previously, prosthesis manufacturers have attempted to simplify this process by providing charts that include the expected EOA for their prosthesis, already indexed into an array of BSA values. One caveat with these charts is that the expected EOA data must truly be reliable, or the charts will misguide the implanting surgeon. Manufacturer-provided charts could be improved by standardizing the EOA data, with one potential source being the hemodynamic data submitted to the United States Food and Drug Administration. This review discusses PPM, manufacturer-provided EOA charts, and the regulation of EOA data.

21 CFR 888.3730 - Toe joint phalangeal (hemi-toe) polymer prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Toe joint phalangeal (hemi-toe) polymer prosthesis. 888.3730 Section 888.3730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (hemi-toe) polymer prosthesis. (a) Identification. A toe joint phalangeal (hemi-toe) polymer prosthesis...

21 CFR 888.3760 - Wrist joint carpal scaphoid polymer prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wrist joint carpal scaphoid polymer prosthesis. 888.3760 Section 888.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... scaphoid polymer prosthesis. (a) Identification. A wrist joint carpal scaphoid polymer prosthesis is a one...

21 CFR 888.3770 - Wrist joint carpal trapezium polymer prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wrist joint carpal trapezium polymer prosthesis. 888.3770 Section 888.3770 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... trapezium polymer prosthesis. (a) Identification. A wrist joint carpal trapezium polymer prosthesis is a one...

21 CFR 888.3750 - Wrist joint carpal lunate polymer prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wrist joint carpal lunate polymer prosthesis. 888.3750 Section 888.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... lunate polymer prosthesis. (a) Identification. A wrist joint carpal lunate prosthesis is a one-piece...

21 CFR 888.3750 - Wrist joint carpal lunate polymer prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Wrist joint carpal lunate polymer prosthesis. 888.3750 Section 888.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... lunate polymer prosthesis. (a) Identification. A wrist joint carpal lunate prosthesis is a one-piece...

21 CFR 888.3730 - Toe joint phalangeal (hemi-toe) polymer prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Toe joint phalangeal (hemi-toe) polymer prosthesis. 888.3730 Section 888.3730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (hemi-toe) polymer prosthesis. (a) Identification. A toe joint phalangeal (hemi-toe) polymer prosthesis...

21 CFR 888.3770 - Wrist joint carpal trapezium polymer prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Wrist joint carpal trapezium polymer prosthesis. 888.3770 Section 888.3770 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... trapezium polymer prosthesis. (a) Identification. A wrist joint carpal trapezium polymer prosthesis is a one...

21 CFR 888.3760 - Wrist joint carpal scaphoid polymer prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Wrist joint carpal scaphoid polymer prosthesis. 888.3760 Section 888.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... scaphoid polymer prosthesis. (a) Identification. A wrist joint carpal scaphoid polymer prosthesis is a one...

21 CFR 888.3750 - Wrist joint carpal lunate polymer prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Wrist joint carpal lunate polymer prosthesis. 888.3750 Section 888.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... lunate polymer prosthesis. (a) Identification. A wrist joint carpal lunate prosthesis is a one-piece...

21 CFR 888.3730 - Toe joint phalangeal (hemi-toe) polymer prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Toe joint phalangeal (hemi-toe) polymer prosthesis. 888.3730 Section 888.3730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (hemi-toe) polymer prosthesis. (a) Identification. A toe joint phalangeal (hemi-toe) polymer prosthesis...

21 CFR 888.3770 - Wrist joint carpal trapezium polymer prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Wrist joint carpal trapezium polymer prosthesis. 888.3770 Section 888.3770 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... trapezium polymer prosthesis. (a) Identification. A wrist joint carpal trapezium polymer prosthesis is a one...

21 CFR 888.3760 - Wrist joint carpal scaphoid polymer prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Wrist joint carpal scaphoid polymer prosthesis. 888.3760 Section 888.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... scaphoid polymer prosthesis. (a) Identification. A wrist joint carpal scaphoid polymer prosthesis is a one...

21 CFR 888.3770 - Wrist joint carpal trapezium polymer prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Wrist joint carpal trapezium polymer prosthesis. 888.3770 Section 888.3770 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... trapezium polymer prosthesis. (a) Identification. A wrist joint carpal trapezium polymer prosthesis is a one...

21 CFR 888.3750 - Wrist joint carpal lunate polymer prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Wrist joint carpal lunate polymer prosthesis. 888.3750 Section 888.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... lunate polymer prosthesis. (a) Identification. A wrist joint carpal lunate prosthesis is a one-piece...

21 CFR 888.3760 - Wrist joint carpal scaphoid polymer prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Wrist joint carpal scaphoid polymer prosthesis. 888.3760 Section 888.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... scaphoid polymer prosthesis. (a) Identification. A wrist joint carpal scaphoid polymer prosthesis is a one...

21 CFR 888.3730 - Toe joint phalangeal (hemi-toe) polymer prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Toe joint phalangeal (hemi-toe) polymer prosthesis. 888.3730 Section 888.3730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (hemi-toe) polymer prosthesis. (a) Identification. A toe joint phalangeal (hemi-toe) polymer prosthesis...

21 CFR 888.3750 - Wrist joint carpal lunate polymer prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Wrist joint carpal lunate polymer prosthesis. 888.3750 Section 888.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... lunate polymer prosthesis. (a) Identification. A wrist joint carpal lunate prosthesis is a one-piece...

21 CFR 888.3730 - Toe joint phalangeal (hemi-toe) polymer prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Toe joint phalangeal (hemi-toe) polymer prosthesis. 888.3730 Section 888.3730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (hemi-toe) polymer prosthesis. (a) Identification. A toe joint phalangeal (hemi-toe) polymer prosthesis...

21 CFR 888.3760 - Wrist joint carpal scaphoid polymer prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Wrist joint carpal scaphoid polymer prosthesis. 888.3760 Section 888.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... scaphoid polymer prosthesis. (a) Identification. A wrist joint carpal scaphoid polymer prosthesis is a one...

21 CFR 888.3770 - Wrist joint carpal trapezium polymer prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Wrist joint carpal trapezium polymer prosthesis. 888.3770 Section 888.3770 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... trapezium polymer prosthesis. (a) Identification. A wrist joint carpal trapezium polymer prosthesis is a one...

Biomechanical Analysis of Porous Additive Manufactured Cages for Lateral Lumbar Interbody Fusion: A Finite Element Analysis.

PubMed

Zhang, Zhenjun; Li, Hui; Fogel, Guy R; Liao, Zhenhua; Li, Yang; Liu, Weiqiang

2018-03-01

A porous additive manufactured (AM) cage may provide stability similar to that of traditional solid cages and may be beneficial to bone ingrowth. The biomechanical influence of various porous cages on stability, subsidence, stresses in cage, and facet contact force has not been fully described. The purpose of this study was to verify biomechanical effects of porous AM cages. The surgical finite element models with various cages were constructed. The partially porous titanium (PPT) cages and fully porous titanium (FPT) cages were applied. The mechanical parameters of porous materials were obtained by mechanical test. Then the porous AM cages were compared with solid titanium (TI) cage and solid polyetheretherketone (PEEK) cage. The 4 motion modes were simulated. Range of motion (ROM), cage stress, end plate stress, and facet joint force (FJF) were compared. For all the surgical models, ROM decreased by >90%. Compared with TI and PPT cages, PEEK and FPT cages substantially reduced the maximum stresses in cage and end plate in all motion modes. Compared with PEEK cages, the stresses in cage and end plate for FPT cages decreased, whereas the ROM increased. Comparing FPT cages, the stresses in cage and end plate decreased with increasing porosity, whereas ROM increased with increasing porosity. After interbody fusion, FJF was substantially reduced in all motion modes except for flexion. Fully porous cages may offer an alternative to solid PEEK cages in lateral lumbar interbody fusion. However, it may be prudent to further increase the porosity of the cage. Copyright © 2017 Elsevier Inc. All rights reserved.

Prosthesis rejection in acquired major upper-limb amputees: a population-based survey.

PubMed

Østlie, Kristin; Lesjø, Ingrid Marie; Franklin, Rosemary Joy; Garfelt, Beate; Skjeldal, Ola Hunsbeth; Magnus, Per

2012-07-01

To estimate the rates of primary and secondary prosthesis rejection in acquired major upper-limb amputees (ULAs), to describe the most frequently reported reasons for rejection and to estimate the influence of background factors on the risk of rejection. Cross-sectional study analysing population-based questionnaire data (n = 224). Effects were analysed by logistic regression analyses and Cox regression analyses. Primary prosthesis rejection was found in 4.5% whereas 13.4% had discontinued prosthesis use. The main reasons reported for primary non-wear were a perceived lack of need and discrepancies between perceived need and the prostheses available. The main reasons reported for secondary prosthesis rejection were dissatisfaction with prosthetic comfort, function and control. Primary prosthesis rejection was more likely in ULAs amputated at high age and in ULAs with proximal amputations. Secondary prosthesis rejection was more likely in proximal ULAs and in women. Clinicians should be aware of the increased risk of rejection in proximal ULAs, elderly ULAs and in women. Emphasising individual needs will probably facilitate successful prosthetic fitting. Improved prosthesis quality and individualised prosthetic training may increase long-term prosthesis use. Further studies of the effect of prosthetic training and of the reasons for rejection of different prosthetic types are suggested.

Novel knee joint mechanism of transfemoral prosthesis for stair ascent.

PubMed

Inoue, Koh; Wada, Takahiro; Harada, Ryuchi; Tachiwana, Shinichi

2013-06-01

The stability of a transfemoral prosthesis when walking on flat ground has been established by recent advances in knee joint mechanisms and their control methods. It is, however, difficult for users of a transfemoral prosthesis to ascend stairs. This difficulty is mainly due to insufficient generation of extension moment around the knee joint of the prosthesis to lift the body to the next step on the staircase and prevent any unexpected flexion of the knee joint in the stance phase. Only a prosthesis with an actuator has facilitated stair ascent using a step-over-step gait (1 foot is placed per step). However, its use has issues associated with the durability, cost, maintenance, and usage environment. Therefore, the purpose of this research is to develop a novel knee joint mechanism for a prosthesis that generates an extension moment around the knee joint in the stance phase during stair ascent, without the use of any actuators. The proposed mechanism is based on the knowledge that the ground reaction force increases during the stance phase when the knee flexion occurs. Stair ascent experiments with the prosthesis showed that the proposed prosthesis can realize stair ascent without any undesirable knee flexion. In addition, the prosthesis is able to generate a positive knee joint moment power in the stance phase even without any power source.

BIOENERGETIC DIFFERENCES DURING WALKING AND RUNNING IN TRANSFEMORAL AMPUTEE RUNNERS USING ARTICULATING AND NON-ARTICULATING KNEE PROSTHESES

PubMed Central

Highsmith, M. Jason; Kahle, Jason T.; Miro, Rebecca M.; Mengelkoch, Larry J.

2016-01-01

Transfemoral amputation (TFA) patients require considerably more energy to walk and run than non-amputees. The purpose of this study was to examine potential bioenergetic differences (oxygen uptake (VO2), heart rate (HR), and ratings of perceived exertion (RPE)) for TFA patients utilizing a conventional running prosthesis with an articulating knee mechanism versus a running prosthesis with a non-articulating knee joint. Four trained TFA runners (n = 4) were accommodated to and tested with both conditions. VO2 and HR were significantly lower (p ≤ 0.05) in five of eight fixed walking and running speeds for the prosthesis with an articulating knee mechanism. TFA demonstrated a trend for lower RPE at six of eight walking speeds using the prosthesis with the articulated knee condition. A trend was observed for self-selected walking speed, self-selected running speed, and maximal speed to be faster for TFA subjects using the prosthesis with the articulated knee condition. Finally, all four TFA participants subjectively preferred running with the prosthesis with the articulated knee condition. These findings suggest that, for trained TFA runners, a running prosthesis with an articulating knee prosthesis reduces ambulatory energy costs and enhances subjective perceptive measures compared to using a non-articulating knee prosthesis. PMID:28066524

Postpneumonectomy syndrome in children: advantages and long-term follow-up of expandable prosthesis.

PubMed

Podevin, G; Larroquet, M; Camby, C; Audry, G; Plattner, V; Heloury, Y

2001-09-01

Pneumonectomy in children can be complicated by a severe mediastinal shift, which leads to bronchial stretching resulting in severe respiratory failure. This postpneumonectomy syndrome can be corrected by inserting a prosthesis in the empty side of the chest. Forty-two children, from 6 months to 15 years old, underwent a pneumonectomy. Seven of these patients were treated surgically for severe manifestations of postpneumonectomy syndrome. First insertion of an expandable prosthesis was followed up in 5 cases by its replacement with a breast prosthesis in adolescence. The expandable prosthesis was injected periodically with saline solution to maintain the mediastinum in a midline position as the children grew. The mean delay between pneumonectomy and first prosthesis implantation was 5 years (range, 11 months to 8 years). Pulmonary function tests showed a substantial improvement in the obstructive syndrome in all patients except one, in whom the functional improvement was moderate. The mean follow-up after the expandable prosthesis implantation was 6 years (range, 6 months to 10 years) and all patients are doing well. The insertion of an intrathoracic prosthesis can dramatically improve the clinical symptoms and reduce the functional obstructive syndrome. The expandable prosthesis allowed for progressive, well-tolerated recentering of the mediastinum and adjustment for growth. Copyright 2001 by W.B. Saunders Company.

Malrotation of the McGhan Style 510 prosthesis.

PubMed

Schots, Jeroen M P; Fechner, Maarten R; Hoogbergen, Maarten M; van Tits, Herm W H J

2010-07-01

Anatomically shaped cohesive silicone breast implants are frequently used in aesthetic and reconstructive surgery. After successful results with the Style 410 prosthesis, McGhan (Natrelle, Allergan) introduced the Style 510 prosthesis. After using this novel prosthesis, the authors encountered a high number of prosthesis malrotations on self-reported follow-up. Therefore, a retrospective medical record review was performed to determine the prevalence of malrotation of the Style 510 prosthesis. From January of 2005 to December of 2006, 73 (146 prostheses) aesthetic augmentation mammaplasty procedures were performed using Style 510 prostheses. All prostheses were placed subglandularly through an inframammary incision. The postsurgical protocol for the first 3 weeks involved wearing a nonwired compression bra, abstinence from sports activities, and abstinence from heavy labor. Standard follow-up was at 1 week, 3 months, and if necessary. On self-reported follow-up, 8.2 percent of all prostheses were rotated. These rotations all occurred unilaterally after a mean period of 10 months (range, 3 to 19 months). No relation to an inciting incident or prosthesis volume could be found. The number of rotations of the Style 510 prosthesis seen after primary aesthetic breast augmentation is high. An obvious cause of this major problem has not been found. This led the authors to discontinue using the Style 510 prosthesis for primary aesthetic mammary augmentations in their practice.

Biomechanical evaluation of two types of short-stemmed hip prostheses compared to the trust plate prosthesis by three-dimensional measurement of micromotions.

PubMed

Fottner, Andreas; Schmid, Markus; Birkenmaier, Christof; Mazoochian, Farhad; Plitz, Wolfgang; Volkmar, Jansson

2009-06-01

Stemless and short-stemmed hip prostheses have been developed to preserve femoral bone stock. While all these prostheses claim a more or less physiological load transfer, clinical long-term results are only available for the stemless thrust plate prosthesis. In this study, the in vitro primary stability of the thrust plate prosthesis was compared to two types of short-stemmed prostheses. In addition to the well-established Mayo prosthesis, the modular Metha prosthesis was tested using cone adapters with 130 degrees and 140 degrees neck-shaft-angles. The prostheses were implanted in composite femurs and loaded dynamically (300-1700 N). Three-dimensional micromotions at the bone-prosthesis interface were measured. In addition, the three-dimensional deformations at the surface of the composite femur were measured to gain data on the strain distribution. For all tested prostheses, the micromotions did not exceed 150 microm, the critical value for osteointegration. The thrust plate prosthesis revealed similar motions as the short-stemmed prostheses. The short-stemmed prosthesis with the 130 degrees cone tended to have the highest micromotions of all tested short-stemmed prostheses. The thrust plate prosthesis revealed the lowest alteration of bone surface deformation after implantation. The comparably low micromotions of the thrust plate prosthesis and the short-stemmed prostheses should be conducive to osseous integration. The higher alteration of load transmission after implantation reveals a higher risk of stress shielding for the short-stemmed prostheses.

Can We Improve the Tolerance of an Ocular Prosthesis by Enhancing Its Surface Finish?

PubMed

Litwin, Andre S; Worrell, Emma; Roos, Jonathan C P; Edwards, Barry; Malhotra, Raman

Patients who wear an ocular prosthesis frequently suffer with dry eye symptoms and socket discharge, often on a daily basis. The aim of the study was to determine whether a smoother, optical quality polish of the prosthesis' surface could improve symptoms and wear tolerance. The study was designed as single-center, single-masked, prospective randomized controlled trial. Eighty-eight consecutive patients undergoing annual ocular prosthesis maintenance review were approached from the prosthesis clinic. Forty-one out of 49 eligible patients were recruited. Participants were randomized to either a standard or a higher "optical quality" polish of their prosthesis. At entry to the trial, at 1 month, and 12 months they completed a questionnaire covering cleaning, lubricant use, inflammation, discomfort, and discharge. Lower scores indicated better tolerance of the prosthesis. At each visit, the prosthesis was stained and photographed against a standard background to assess deposit build up. Primary outcome measures were 1) a subjective questionnaire score and 2) an objective assessment of surface deposit build-up on prosthetic eyes by standardized photographic grading. Forty-one patients participated in the study. The median age of their prosthesis was 36 months (range 9 months-40 years). There was no statistically significant difference in questionnaire scores or deposit build up between the 2 groups at baseline. By 12-months, the higher optical quality polish showed a statistically significant reduction in symptoms and frequency of discharge (2.19 vs. 3.85; p = 0.05-lower scores better). Scoring of the prosthesis' deposit build-up showed a significant difference at 1 month, but this was not sustained at 12 months. Creating an optical quality finish to an ocular prosthesis reduces deposit build up on artificial eyes. The authors found this modification improved patient tolerance at 12 months.

Visualisation of upper limb activity using spirals: A new approach to the assessment of daily prosthesis usage.

PubMed

Chadwell, Alix; Kenney, Laurence; Granat, Malcolm; Thies, Sibylle; Head, John S; Galpin, Adam

2018-02-01

Current outcome measures used in upper limb myoelectric prosthesis studies include clinical tests of function and self-report questionnaires on real-world prosthesis use. Research in other cohorts has questioned both the validity of self-report as an activity assessment tool and the relationship between clinical functionality and real-world upper limb activity. Previously, 1 we reported the first results of monitoring upper limb prosthesis use. However, the data visualisation technique used was limited in scope. Methodology development. To introduce two new methods for the analysis and display of upper limb activity monitoring data and to demonstrate the potential value of the approach with example real-world data. Upper limb activity monitors, worn on each wrist, recorded data on two anatomically intact participants and two prosthesis users over 1 week. Participants also filled in a diary to record upper limb activity. Data visualisation was carried out using histograms, and Archimedean spirals to illustrate temporal patterns of upper limb activity. Anatomically intact participants' activity was largely bilateral in nature, interspersed with frequent bursts of unilateral activity of each arm. At times when the prosthesis was worn prosthesis users showed very little unilateral use of the prosthesis (≈20-40 min/week compared to ≈350 min/week unilateral activity on each arm for anatomically intact participants), with consistent bias towards the intact arm throughout. The Archimedean spiral plots illustrated participant-specific patterns of non-use in prosthesis users. The data visualisation techniques allow detailed and objective assessment of temporal patterns in the upper limb activity of prosthesis users. Clinical relevance Activity monitoring offers an objective method for the assessment of upper limb prosthesis users' (PUs) activity outside of the clinic. By plotting data using Archimedean spirals, it is possible to visualise, in detail, the temporal patterns of upper limb activity. Further work is needed to explore the relationship between traditional functional outcome measures and real-world prosthesis activity.

Functional evaluation of a CAD/CAM prosthesis for immediate defect repair after total maxillectomy: a case series of 18 patients with maxillary sinus cancer.

PubMed

Jiang, Fei-Fei; Hou, Yan; Lu, Li; Ding, Xiao-Xu; Li, Wei; Yan, Ai-Hui

2015-01-01

To evaluate the facial profiles and functional recovery of 18 patients treated by a computer-aided designed/manufactured hollow obturator prosthesis (CAD/CAM prosthesis) after total maxillectomy for malignant maxillary sinus tumor. A retrospective observational study was performed to evaluate the facial profiles and functional recovery of 18 patients with T3-4a N0 M0 maxillary sinus cancer, who were treated by total maxillectomy and simultaneous implantation of a computer-aided designed/manufactured hollow obturator prosthesis (CAD/CAM prosthesis). Follow-ups were performed 1, 3, 6, and 12 months after surgery. Facial measurements, speech intelligibility, and chewing and swallowing functions were examined. Thirteen patients converted to a permanent prosthesis 6 months after surgery. Comparisons were made between patients with and without the CAD/CAM or permanent prosthesis at various times using SPSS13.0 statistical software (SPSS Inc., Chicago, IL, USA). Speech intelligibility, facial depression, and eyeball prolapse results showed improvements with prosthesis use at 1, 3, and 6 months after surgery (p < 0.05). Swallowing function improved from level V to level II-IV with prosthesis use at 1, 3, and 6 months, and reached level I or II with permanent prosthesis use at 12 months after surgery. Simultaneous CAD/CAM prosthesis implantation recovered the facial profile, enhanced the speaking, swallowing, and chewing functions, and improved the quality of life of patients. Tumor recurrence can be detected by direct observation of the postoperative maxillary cavity. Therefore, this operation is recommended for simultaneous excision repair and functional reconstruction after total maxillectomy. This surgical treatment of maxillary sinus cancer is applied rarely in China, but it has a good effect based on our observation. Simultaneous CAD/CAM prosthesis implantation after total maxillectomy can recover the facial profile, enhance the speaking, swallowing, and chewing functions, and improve the quality of life of patients. Tumor recurrence can be detected by direct observation of the postoperative maxillary cavity. This technique avoids the need for dental implants because the bottom part of the prosthesis contains a palatal plate with dentures. © 2014 Wiley Periodicals, Inc.

Replacement of the valvular prosthesis in a patient with a Bentall procedure.

PubMed

Panos, A L; Teoh, K T; Wilson, J K; Salerno, T A

1992-09-01

Patients who have had the Bentall-DeBono procedure using a composite conduit with a tissue valvular prosthesis pose a great challenge when problems develop with the tissue prosthesis. We herein report the surgical management of one such case, in which the valvular prosthesis was removed and replaced without replacement of the conduit.

Vacuum form sheet as a guide for fabrication of orbital prosthesis.

PubMed

Dugad, Jinesh A; Dholam, Kanchan P; Chougule, Arati T

2014-08-01

Rehabilitation with an orbital prosthesis is done when surgical reconstruction is not possible or affordable in patients with orbital exenteration. Fabrication of orbital prosthesis requires precision in placement of the ocular portion of the prosthesis on the facial moulage. This method describes the use of a vacuum formed sheet for making an orbital template that acts as a guide for achieving optimum orientation of the ocular portion of the prosthesis. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Management of an Anophthalmic Patient by the Fabrication of Custom Made Ocular Prosthesis

PubMed Central

SINGH, Meenakshi; NAYAK, Meghanand; SOLANKI, Jitender; GUPTA, Sarika; SINGH, Anjali

2015-01-01

The loss or disfigurement of a body parts specially that pertaining to the face has a deep psychological and social impact on the patient. After enucleation, evisceration or exteneration of the eye, the aim of an ocular prosthesis should be to restore the natural appearance, install confidence and a sense social acceptability in the patient. Custom made prosthesis has several advantages over the stock eye prosthesis. This article illustrates rehabilitation of the enucleated right eye of a patient with a custom made ocular prosthesis. PMID:26715901

Furnished Cage System and Hen Well-Being: Comparative Effects of Furnished Cages and Battery Cages on Behavioral Exhibitions in White Leghorn Chickens

USDA-ARS?s Scientific Manuscript database

The battery cage system is being banned in the European Union before or by 2012; and the furnished cage system will be the only cage system allowed after 2012. This study was conducted to examine the different effects of caging systems, furnished cages vs. battery cages, on bird behaviors. One hundr...

Use of prostheses in lower limb amputee patients due to peripheral arterial disease

PubMed Central

Chamlian, Therezinha Rosane

2014-01-01

Objective To evaluate the indication of prosthesis during rehabilitation and the maintenance of their use or abandonment rate after discharge, as well as mortality of lower limb amputees due to peripheral arterial disease. Methods A retrospective and cross-sectional study carried out with lower limb amputee patients, at transfemoral and transtibial levels, due to vascular conditions. The sample was composed of 310 patients (205 men, 105 women, mean age 61.8 years), transfemoral (142) and transtibial (150) levels, unilateral or bilateral (18). A total of 217 were fitted with prosthesis and 93 did not. Nonparametric statistical tests with equality of two proportions, 95% confidence interval and p value <0,05 were used. Results Out of 195 patients we contacted, 151 were fitted with prosthesis and 44 not. Of those that were fitted with prosthesis, 54 still use it, 80 abandoned and 17 died. In the group without prosthesis, 27 were on wheelchair and 17 died. Mortality is statistically higher among patients who were not fitted with prosthesis and 34 death occur, on average, 3.91 years after amputation. Survival time of patients who were not fitted with prosthesis was smaller than those were fitted. Conclusion The use of prosthesis in lower limb amputees, due to vascular conditions, during rehabilitation is high. However, maintenance of prosthesis is not frequent after discharge. Early and high mortality is observed mainly among diabetic patients. PMID:25628194

Prosthesis use in adult acquired major upper-limb amputees: patterns of wear, prosthetic skills and the actual use of prostheses in activities of daily life.

PubMed

Østlie, Kristin; Lesjø, Ingrid Marie; Franklin, Rosemary Joy; Garfelt, Beate; Skjeldal, Ola Hunsbeth; Magnus, Per

2012-11-01

To describe patterns of prosthesis wear and perceived prosthetic usefulness in adult acquired upper-limb amputees (ULAs). To describe prosthetic skills in activities of daily life (ADL) and the actual use of prostheses in the performance of ADL tasks. To estimate the influence of prosthetic skills on actual prosthesis use and the influence of background factors on prosthetic skills and actual prosthesis use. Cross-sectional study analysing population-based questionnaire data (n = 224) and data from interviews and clinical testing in a referred/convenience sample of prosthesis-wearing ULAs (n = 50). Effects were analysed using linear regression. 80.8% wore prostheses. 90.3% reported their most worn prosthesis as useful. Prosthetic usefulness profiles varied with prosthetic type. Despite demonstrating good prosthetic skills, the amputees reported actual prosthesis use in only about half of the ADL tasks performed in everyday life. In unilateral amputees, increased actual use was associated with sufficient prosthetic training and with the use of myoelectric vs cosmetic prostheses, regardless of amputation level. Prosthetic skills did not affect actual prosthesis use. No background factors showed significant effect on prosthetic skills. Most major ULAs wear prostheses. Individualised prosthetic training and fitting of myoelectric rather than passive prostheses may increase actual prosthesis use in ADL.

Early outcome of TKA with a medial pivot fixed-bearing prosthesis is worse than with a PFC mobile-bearing prosthesis.

PubMed

Kim, Young-Hoo; Yoon, Sung-Hwan; Kim, Jun-Shik

2009-02-01

Although the design features of the Medial Pivot fixed-bearing prosthesis reportedly improve kinematics compared with TKAs using fixed-bearings, clinical improvements have not been reported. We asked whether the clinical and radiographic outcomes, ranges of motion of the knee, patient satisfaction, and complication rates would be better in knees with a Medial Pivot fixed-bearing prosthesis than in those with a PFC Sigma mobile-bearing prosthesis. We compared the results of 92 patients who had a Medial Pivot fixed-bearing prosthesis implanted in one knee and a PFC Sigma mobile-bearing prosthesis implanted in the other. There were 85 women and seven men with a mean age of 69.5 years (range, 55-81 years). The minimum followup was 2 years (mean, 2.6 years; range, 2-3 years). The patients were assessed clinically and radiographically using the rating systems of the Hospital for Special Surgery and the Knee Society at 3 months, 1 year, and annually thereafter. Contrary to expectations, we found worse early clinical outcomes, smaller ranges of knee motion, less patient satisfaction, and a higher complication rate for the Medial Pivot fixed-bearing prosthesis than for the PFC Sigma mobile-bearing prosthesis. Level I, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Frequency of technical complications in fixed implant prosthesis: the effect of prosthesis screw emergence correction by CAD-CAM.

PubMed

Anitua, Eduardo; Flores, Carlos; Piñas, Laura; Alkhraisat, Mohammad

2018-06-05

CAD-CAM technology permits the angular correction of screw emergence into the prosthesis, however there is lack of controlled clinical studies that assess the frequency of technical complications in angled screw channel restorations. This controlled clinical study was designed to assess technical incidences in angled screw channel restorations. Patients having implant prosthesis placed between November, 2014 and December, 2015 were screened. The patients were selected if they received prosthesis with up to 30º correction of the prosthesis screw emergence and had at least one non-angulated prosthesis (screw-retained). All the prostheses were located completely/partially in the posterior region. The frequency of technical complications was the principal variable. A total of 52 patients with a mean age of 62 ± 10 years participated with a total 110 prostheses (55 in the test group and 55 in the control group). A total of 11 technical complications occurred (7 in the test group and 4 in the control group). These differences were not statistically significant. All the prostheses in both groups survived the follow-up. The correction of the screw emergence into the prosthesis has not increased the risk of technical complications in CAD-CAM implant prostheses.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janik, Gregory

Renders, saves, and analyzes pressure from several sensors in a prosthesis™ socket. The program receives pressure data from 64 manometers and parses the pressure for each individual sensor. The program can then display those pressures as number in a table. The program also interpolates pressures between manometers to create a larger set of data. This larger set of data is displayed as a simple contour plot. That same contour plot can also be placed on a three-dimensional surface in the shape of a prosthesis.This program allows for easy identification of high pressure areas in a prosthesis to reduce the user™smore » discomfort. The program parses the sensor pressures into a human-readable numeric format. The data may also be used to actively adjust bladders within the prosthesis to spread out pressure in real time, according to changing demands placed on the prosthesis. Interpolation of the pressures to create a larger data set makes it even easier for a human to identify particular areas of the prosthesis that are under high pressure. After identifying pressure points, a prosthetician can then redesign the prosthesis and/or command the bladders in the prosthesis to attempt to maintain constant pressures.« less

Allograft-prosthesis composites after bone tumor resection at the proximal tibia.

PubMed

Biau, David Jean; Dumaine, Valérie; Babinet, Antoine; Tomeno, Bernard; Anract, Philippe

2007-03-01

The survival of irradiated allograft-prosthesis composites at the proximal tibia is mostly unknown. However, allograft-prosthesis composites have proved beneficial at other reconstruction sites. We presumed allograft-prosthesis composites at the proximal tibia would improve survival and facilitate reattachment of the extensor mechanism compared with that of conventional (megaprostheses) reconstructions. We retrospectively reviewed 26 patients who underwent resection of proximal tibia tumors followed by reconstruction with allo-graft-prosthesis composites. Patients received Guepar massive custom-made fully constrained prostheses. Allografts were sterilized with gamma radiation, and the stems were cemented into the allograft and host bone. The minimum followup was 6 months (median, 128 months; range, 6-195 months). Fourteen patients had one or more components removed. The median allograft-prosthesis composite survival was 102 months (95% confidence interval, 64.2-infinity). Of the 26 allografts, seven fractured, six showed signs of partial resorption, and six had infections develop. Seven allografts showed signs of fusion with the host bone. Six extensor mechanism reconstructions failed. Allograft-prosthesis composites sterilized by gamma radiation yielded poor results for proximal tibial reconstruction as complications and failures were common. We do not recommend irradiated allograft-prosthesis composites for proximal tibia reconstruction.

Simulation of a slope adapting ankle prosthesis provided by semi-active damping.

PubMed

LaPrè, Andrew K; Sup, Frank

2011-01-01

Modern passive prosthetic foot/ankles cannot adapt to variations in ground slope. The lack of active adaptation significantly compromises an amputee's balance and stability on uneven terrains. To address this deficit, this paper proposes an ankle prosthesis that uses semi-active damping as a mechanism to provide active slope adaptation. The conceptual ankle prosthesis consists of a modulated damper in series with a spring foot that allows the foot to conform to the angle of the surface in the sagittal plane. In support of this approach, biomechanics data is presented showing unilateral transtibial amputees stepping on a wedge with their daily-use passive prosthesis. Based on this data, a simulation of the ankle prosthesis with semi-active damping is developed. The model shows the kinematic adaptation of the prosthesis to sudden changes in ground slope. The results show the potential of an ankle prosthesis with semi-active damping to actively adapt to the ground slope at each step.

The polymethyl methacrylate cervical cage for treatment of cervical disk disease Part III. Biomechanical properties.

PubMed

Chen, Jyi-Feng; Lee, Shih-Tseng

2006-10-01

In a previous article, we used the PMMA cervical cage in the treatment of single-level cervical disk disease and the preliminary clinical results were satisfactory. However, the mechanical properties of the PMMA cage were not clear. Therefore, we designed a comparative in vitro biomechanical study to determine the mechanical properties of the PMMA cage. The PMMA cervical cage and the Solis PEEK cervical cage were compressed in a materials testing machine to determine the mechanical properties. The compressive yield strength of the PMMA cage (7030 +/- 637 N) was less than that of the Solis polymer cervical cage (8100 +/- 572 N). The ultimate compressive strength of the PMMA cage (8160 +/- 724 N) was less than that of the Solis cage (9100 +/- 634 N). The stiffness of the PMMA cervical cage (8106 +/- 817 N/mm) was greater than that of the Solis cage (6486 +/- 530 N/mm). The elastic modulus of the PMMA cage (623 +/- 57 MPa) was greater than that of the Solis cage (510 +/- 42 MPa). The elongation of PMMA cage (43.5 +/- 5.7%) was larger than that of the Solis cage (36.1 +/- 4.3%). Although the compressive yield strength and ultimate compressive strength of the PMMA cervical cage were less than those of the Solis polymer cage, the mechanical properties are better than those of the cervical vertebral body. The PMMA cage is strong and safe for use as a spacer for cervical interbody fusion. Compared with other cage materials, the PMMA cage has many advantages and no obvious failings at present. However, the PMMA cervical cage warrants further long-term clinical study.

In vitro biomechanical comparison after fixed- and mobile-core artificial cervical disc replacement versus fusion

PubMed Central

Lou, Jigang; Li, Yuanchao; Wang, Beiyu; Meng, Yang; Wu, Tingkui; Liu, Hao

2017-01-01

Abstract In vitro biomechanical analysis after cervical disc replacement (CDR) with a novel artificial disc prosthesis (mobile core) was conducted and compared with the intact model, simulated fusion, and CDR with a fixed-core prosthesis. The purpose of this experimental study was to analyze the biomechanical changes after CDR with a novel prosthesis and the differences between fixed- and mobile-core prostheses. Six human cadaveric C2–C7 specimens were biomechanically tested sequentially in 4 different spinal models: intact specimens, simulated fusion, CDR with a fixed-core prosthesis (Discover, DePuy), and CDR with a mobile-core prosthesis (Pretic-I, Trauson). Moments up to 2 Nm with a 75 N follower load were applied in flexion–extension, left and right lateral bending, and left and right axial rotation. The total range of motion (ROM), segmental ROM, and adjacent intradiscal pressure (IDP) were calculated and analyzed in 4 different spinal models, as well as the differences between 2 disc prostheses. Compared with the intact specimens, the total ROM, segmental ROM, and IDP at the adjacent segments showed no significant difference after arthroplasty. Moreover, CDR with a mobile-core prosthesis presented a little higher values of target segment (C5/6) and total ROM than CDR with a fixed-core prosthesis (P > .05). Besides, the difference in IDP at C4/5 after CDR with 2 prostheses was without statistical significance in all the directions of motion. However, the IDP at C6/7 after CDR with a mobile-core prosthesis was lower than CDR with a fixed-core prosthesis in flexion, extension, and lateral bending, with significant difference (P < .05), but not under axial rotation. CDR with a novel prosthesis was effective to maintain the ROM at the target segment and did not affect the ROM and IDP at the adjacent segments. Moreover, CDR with a mobile-core prosthesis presented a little higher values of target segment and total ROM, but lower IDP at the inferior adjacent segment than CDR with a fixed-core prosthesis. PMID:29019902

Difference in occurrence of heterotopic ossification according to prosthesis type in the cervical artificial disc replacement.

PubMed

Yi, Seong; Kim, Keung Nyun; Yang, Moon Sul; Yang, Joong Won; Kim, Hoon; Ha, Yoon; Yoon, Do Heum; Shin, Hyun Chul

2010-07-15

Retrospective study of the difference of heterotopic ossification (HO) occurrence according to 3 different types of prosthesis. This study was designed to investigate the difference of HO occurrence according to different type of prosthesis. HO is defined as formation of the bone outside the skeletal system. Reported HO occurrence rate in cervical artificial disc replacement (ADR) was unexpectedly high and varied. But the influencing factors of HO in cervical ADR have not been elucidated well. The prosthesis-related factors for making difference of HO occurrence were investigated in this study. A total of 170 patients undergoing cervical arthroplasty with the Bryan cervical disc prosthesis (Medtroic Sofamor Danek, Memphis, TN), Mobi-C disc prosthesis (LDR Medical, Troyes, France), and ProDisc-C (Synthes, Inc., West Chester, PA) were included. Cervical lateral radiographs obtained before and after surgery were used to identify HO. Occurrence rate, occurrence-free period, location, and grade of HOs were investigated according to the different prosthesis. Each prosthesis group included patients as follows: Bryan disc, 81 patients; Mobi-C, 61 patients; and ProDisc-C, 28 patients. Overall HO rate was 40.6% (69 of 170 patients). Each HO occurrence rate by prosthesis was as follows: the Bryan disc group, 21.0%; Mobi-C group, 52.5%; and the ProDisc-C group, 71.4%. In the survival analysis, all patients showed 27.1 +/- 3.7 months as the median survival. The Bryan disc group showed statistically longer survival (48.4 +/- 7.4 months) than the other groups. Occurrence of HO is an inevitable postoperative complication after cervical ADR. The occurrence rate of HO was higher than our expectation. Moreover, definite differences in occurrence rate according to the prosthesis type were identified by this study.

Seventeen-millimeter St. Jude Medical Regent valve in patients with small aortic annulus: dose moderate prosthesis-patient mismatch matter?

PubMed

Hu, Jia; Qian, Hong; Li, Ya-jiao; Gu, Jun; Zhao, Jing Janice; Zhang, Er-yong

2014-01-17

The study was designed to evaluate the effects of moderate prosthesis-patient mismatch (defined as 0.65 cm(2)/m(2) 

Long-term outcome of giant cell tumors of bone around the knee treated by en bloc resection of tumor and reconstruction with prosthesis.

PubMed

Yu, Xiu-chun; Xu, Ming; Song, Ruo-xian; Fu, Zhi-hou; Liu, Xiao-ping

2010-08-01

To study the long-term outcomes and complications of giant cell tumors around the knee treated with en bloc resection and reconstruction with prosthesis. From January 1991 to March 2005, 19 patients (11 men, 8 women, average age 35.4 years) were treated in our hospital with en bloc resection and reconstruction with domestic prosthesis (15 hinge knee and 4 rotating-hinge knee). The distal femur was involved in 12 and the proximal tibia in 7 cases. Nine tumors were primary and 10 recurrent. All cases were Campanacci grade III. The affected limb functions were evaluated by the Musculoskeletal Tumor Society scoring system. All patients underwent operation successfully with no complications. The mean follow-up time was 128.9 months (60 to 216 months). Apart from one patient who underwent amputation because of wound infection two years after reoperation, the range of knee motion of 18 patients was 30°-110°. The mean functional score of the affected limb was 22.7 (15 to 27 points). The length of the lower extremities was equal in nine cases; the affected limb was 2-9 cm shorter in the other ten cases. Prosthesis fracture and loosening developed in one, prosthesis aseptic loosening in three, and delayed deep infection and prosthesis loosening in two cases. The prosthesis loosening rate was 31.6%. One patient developed a proximal femur fracture. En bloc resection and reconstruction with prosthesis is a feasible method for treating giant cell tumor of bone around the knee. Complications related to the prosthesis, mainly prosthesis loosening and limb shortening, increase gradually with longer survival time. © 2010 Tianjin Hospital and Blackwell Publishing Asia Pty Ltd.

A novel open-tray impression technique for fabrication of a provisional prosthesis on immediate load implants in a completely edentulous arch.

PubMed

Kaneko, Takahiro; Yamagishi, Kiyoshi; Horie, Norio; Shimoyama, Tetsuo

2013-01-01

To evaluate the clinical outcome of a novel open-tray impression technique for fabrication of a provisional prosthesis supported by immediately loaded implants in a completely edentulous arch. An open-tray impression technique was evaluated in this retrospective study that included patients treated between March 2006 and October 2009. Preoperatively, a diagnostic prosthesis was delivered, and a novel open tray was fabricated based on this prosthesis. After implant placement, the impression and interocclusal record were taken simultaneously using the novel open tray. Laboratory-fabricated, screw-retained, all-acrylic resin provisional restorations were delivered on the same day of surgery. The prosthesis was assessed from the day of surgery until replacement with a definitive prosthesis. The study included 21 patients (mean age, 64.5 years) and a total of 125 implants. Of these, 104 implants were immediately loaded. In all patients, well-fitting provisional restorations supported by a minimum of four implants were delivered. Fracture of the first molar cusp was observed in one case after 30 days. However, there was no extensive fracture in the framework or functional disorder of the prosthesis. No implant failed during the follow-up after implant surgery. This protocol enabled fabrication of a well-fitting acrylic resin provisional prosthesis supported by immediately loaded implants because the impression was taken while in centric occlusion and an occlusion identical to the diagnostic prosthesis could be reconstructed.

Furnished cage system and hen well-being: Comparative effects of furnished cages and battery cages on behavioral exhibitions in White Leghorn chickens.

PubMed

Pohle, K; Cheng, H-W

2009-08-01

The battery cage system is being banned in the European Union before or by 2012, and the furnished cage system will be the only cage system allowed after 2012. This study was conducted to examine the different effects of caging systems, furnished cages vs. battery cages, on bird behaviors. One hundred ninety-two 1-d-old non-beak-trimmed Hy-Line W-36 White Leghorn chicks were reared using standard management practices in raised wire cages. At 19 wk of age, the birds were randomly assigned into battery cages or furnished cages. The battery cages were commercial wire cages containing 6 birds per cage, providing 645 cm(2) of floor space per birds. The furnished cages had wire floors and solid metal walls, with perches, a dustbathing area, scratch pads, and a nestbox area with a concealment curtain. Based on the company recommendations, 10 birds were housed per cage, providing a stocking density of 610 cm(2) of floor space per bird. Behavioral observations were conducted using the Noldus Observer software package. The birds were observed at 5-min intervals for the entire light period. The birds housed in battery cages had higher posture and behavioral transitions and increased time spent walking and performing exploratory behavior (P < 0.05, 0.01, respectively), which may indicate they were stressed, resulting in restlessness, whereas the birds housed in furnished cages had higher levels of preening (P < 0.05). Preening has been considered as a comfort behavior in birds. These results may suggest that furnished cages may be a favorable alternative system for housing birds by allowing them to perform certain natural behaviors.

Using Arrays of Microelectrodes Implanted in Residual Peripheral Nerves to Provide Dextrous Control of, and Modulated Sensory Feedback from, a Hand Prosthesis

DTIC Science & Technology

2015-10-01

Modulated Sensory Feedback from, a Hand Prosthesis PRINCIPAL INVESTIGATOR: Bradley Greger, PhD CONTRACTING ORGANIZATION: Arizona State University...Residual Peripheral Nerves to Provide Dextrous Control of, and Modulated Sensory Feedback from, a Hand Prosthesis 5a. CONTRACT NUMBER 5b. GRANT...Peripheral Nerve Interface, Prosthetic Hand, Neural Prosthesis , Sensory Feedback, Micro-stimulation, Electrophysiology, Action Potentials, Micro

[COMPUTER ASSISTED DESIGN AND ELECTRON BEAMMELTING RAPID PROTOTYPING METAL THREE-DIMENSIONAL PRINTING TECHNOLOGY FOR PREPARATION OF INDIVIDUALIZED FEMORAL PROSTHESIS].

PubMed

Liu, Hongwei; Weng, Yiping; Zhang, Yunkun; Xu, Nanwei; Tong, Jing; Wang, Caimei

2015-09-01

To study the feasibility of preparation of the individualized femoral prosthesis through computer assisted design and electron beammelting rapid prototyping (EBM-RP) metal three-dimensional (3D) printing technology. One adult male left femur specimen was used for scanning with 64-slice spiral CT; tomographic image data were imported into Mimics15.0 software to reconstruct femoral 3D model, then the 3D model of individualized femoral prosthesis was designed through UG8.0 software. Finally the 3D model data were imported into EBM-RP metal 3D printer to print the individualized sleeve. According to the 3D model of individualized prosthesis, customized sleeve was successfully prepared through the EBM-RP metal 3D printing technology, assembled with the standard handle component of SR modular femoral prosthesis to make the individualized femoral prosthesis. Customized femoral prosthesis accurately matching with metaphyseal cavity can be designed through the thin slice CT scanning and computer assisted design technology. Titanium alloy personalized prosthesis with complex 3D shape, pore surface, and good matching with metaphyseal cavity can be manufactured by the technology of EBM-RP metal 3D printing, and the technology has convenient, rapid, and accurate advantages.

Flexible and static wrist units in upper limb prosthesis users: functionality scores, user satisfaction and compensatory movements.

PubMed

Deijs, M; Bongers, R M; Ringeling-van Leusen, N D M; van der Sluis, C K

2016-03-15

The current study examines the relevance of prosthetic wrist movement to facilitate activities of daily living or to prevent overuse complaints. Prosthesis hands with wrist flexion/extension capabilities are commercially available, but research on the users' experiences with flexible wrists is limited. In this study, eight transradial amputees using a myoelectric prosthesis tested two prosthesis wrists with flexion/extension capabilities, the Flex-wrist (Otto Bock) and Multi-flex wrist (Motion Control), in their flexible and static conditions. Differences between the wrists were assessed on the levels of functionality, user satisfaction and compensatory movements after two weeks use. No significant differences between flexible and static wrist conditions were found on activity performance tests and standardized questionnaires on satisfaction. Inter-individual variation was remarkably large. Participants' satisfaction tended to be in favour of flexible wrists. All participants but one indicated that they would choose a prosthesis hand with wrist flexion/extension capabilities if allowed a new prosthesis. Shoulder joint angles, reflecting compensatory movements, showed no clear differences between wrist conditions. Overall, positive effects of flexible wrists are hard to objectify. Users seem to be more satisfied with flexible wrists. A person's needs, work and prosthesis skills should be taken into account when prescribing a prosthesis wrist. Nederlands Trial Register NTR3984 .

Adjuvant Maneuvers for Residual Curvature Correction During Penile Prosthesis Implantation in Men with Peyronie's Disease.

PubMed

Berookhim, Boback M; Karpman, Edward; Carrion, Rafael

2015-11-01

The surgical treatment of comorbid erectile dysfunction and Peyronie's disease has long included the implantation of an inflatable penile prosthesis as well as a number of adjuvant maneuvers to address residual curvature after prosthesis placement. To review the various surgical options for addressing curvature after prosthesis placement, with specific attention paid to an original article by Wilson et al. reporting on modeling over a penile prosthesis for the management of Peyronie's disease. A literature review was performed analyzing articles reporting the management of penile curvature in patients undergoing implantation of an inflatable penile prosthesis. Reported improvement in Peyronie's deformity as well as the complication rate associated with the various surgical techniques described. Modeling is a well-established treatment modality among patients with Peyronie's disease undergoing penile prosthesis implantation. A variety of other adjuvant maneuvers to address residual curvature when modeling alone is insufficient has been presented in the literature. Over 20 years of experience with modeling over a penile prosthesis have proven the efficacy and safety of this treatment option, providing the surgeon a simple initial step for the management of residual curvature after penile implantation which allows for the use of additional adjuvant maneuvers in those with significant deformities. © 2015 International Society for Sexual Medicine.

Active upper limb prosthesis based on natural movement trajectories.

PubMed

Ramírez-García, Alfredo; Leija, Lorenzo; Muñoz, Roberto

2010-03-01

The motion of the current prostheses is sequential and does not allow natural movements. In this work, complex natural motion patterns from a healthy upper limb were characterized in order to be emulated for a trans-humeral prosthesis with three degrees of freedom at the elbow. Firstly, it was necessary to define the prosthesis workspace, which means to establish a relationship using an artificial neural network (ANN), between the arm-forearm (3-D) angles allowed by the prosthesis, and its actuators length. The 3-D angles were measured between the forearm and each axis of the reference system attached at the elbow. Secondly, five activities of daily living (ADLs) were analyzed by means of the elbow flexion (EF), the forearm prono-supination (FPS) and the 3-D angles, from healthy subjects, by using a video-based motion analysis system. The 3-D angles were fed to the prosthesis model (ANN) in order to analyze which ADLs could be emulated by the prosthesis. As a result, a prosthesis kinematics approximation was obtained. In conclusion, in spite of the innovative mechanical configuration of the actuators, it was possible to carry out only three of the five ADLs considered. Future work will include improvement of the mechanical configuration of the prosthesis to have greater range of motion.

A new malleostapedotomy prosthesis. Experimental analysis by laser doppler vibrometer in fresh cadaver temporal bones.

PubMed

Vallejo, Luis A; Manzano, María T; Hidalgo, Antonio; Hernández, Alberto; Sabas, Juan; Lara, Hugo; Gil-Carcedo, Elisa; Herrero, David

One of the problems with total ossicular replacement prostheses is their stability. Prosthesis dislocations and extrusions are common in middle ear surgery. This is due to variations in endo-tympanic pressure as well as design defects. The design of this new prosthesis reduces this problem by being joined directly to the malleus handle. The aim of this study is to confirm adequate acoustic-mechanical behaviour in fresh cadaver middle ear of a new total ossicular replacement prosthesis, designed using the finite elements method. Using the doppler vibrometer laser, we analysed the acoustic-mechanical behaviour of a new total ossicular replacement prosthesis in the human middle ear using 10 temporal bones from fresh cadavers. The transfer function of the ears in which we implanted the new prosthesis was superimposed over the non-manipulated ear. This suggests optimum acoustic-mechanical behaviour. The titanium prosthesis analysed in this study demonstrated optimum acoustic-mechanical behaviour. Together with its ease of implantation and post-surgical stability, these factors make it a prosthesis to be kept in mind in ossicular reconstruction. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

Temperature dependence of polyhedral cage volumes in clathrate hydrates

USGS Publications Warehouse

Chakoumakos, B.C.; Rawn, C.J.; Rondinone, A.J.; Stern, L.A.; Circone, S.; Kirby, S.H.; Ishii, Y.; Jones, C.Y.; Toby, B.H.

2003-01-01

The polyhedral cage volumes of structure I (sI) (carbon dioxide, methane, trimethylene oxide) and structure II (sII) (methane-ethane, propane, tetrahydrofuran, trimethylene oxide) hydrates are computed from atomic positions determined from neutron powder-diffraction data. The ideal structural formulas for sI and sII are, respectively, S2L6 ?? 46H2O and S16L???8 ?? 136H2O, where S denotes a polyhedral cage with 20 vertices, L a 24-cage, and L??? a 28-cage. The space-filling polyhedral cages are defined by the oxygen atoms of the hydrogen-bonded network of water molecules. Collectively, the mean cage volume ratio is 1.91 : 1.43 : 1 for the 28-cage : 24-cage : 20-cage, which correspond to equivalent sphere radii of 4.18, 3.79, and 3.37 A??, respectively. At 100 K, mean polyhedral volumes are 303.8, 227.8, and 158.8 A??3 for the 28-cage, 24-cage, and 20-cage, respectively. In general, the 20-cage volume for a sII is larger than that of a sI, although trimethylene oxide is an exception. The temperature dependence of the cage volumes reveals differences between apparently similar cages with similar occupants. In the case of trimethylene oxide hydrate, which forms both sI and sII, the 20-cages common to both structures contract quite differently. From 220 K, the sII 20-cage exhibits a smooth monotonic reduction in size, whereas the sI 20-cage initially expands upon cooling to 160 K, then contracts more rapidly to 10 K, and overall the sI 20-cage is larger than the sII 20-cage. The volumes of the large cages in both structures contract monotonically with decreasing temperature. These differences reflect reoriented motion of the trimethyelene oxide molecule in the 24-cage of sI, consistent with previous spectroscopic and calorimetric studies. For the 20-cages in methane hydrate (sI) and a mixed methane-ethane hydrate (sII), both containing methane as the guest molecule, the temperature dependence of the 20-cage volume in sII is much less than that in sI, but sII is overall larger in volume.

The effects of indwelling voice prosthesis on the quality of life, depressive symptoms, and self-esteem in patients with total laryngectomy.

PubMed

Polat, Beldan; Orhan, Kadir Serkan; Kesimli, Mustafa Caner; Gorgulu, Yasemin; Ulusan, Murat; Deger, Kemal

2015-11-01

This study aims to evaluate the effects of voice rehabilitation with indwelling voice prosthesis on quality of life, depression, anxiety, self-esteem, and sexual functions in laryngectomy patients. Provox-1 was applied to 30 patients who underwent total laryngectomy by opening a tracheoesophageal fistula. WHO Quality of Life-BREF, Beck Depression Inventory, Beck Anxiety Inventory, Rosenberg Self-Esteem Scale, Arizona Sexual Experience Scale forms were asked to be filled out by the patients before voice prosthesis application. These tests were asked to be filled out again 3 months later after the voice prosthesis application. Paired samples and Wilcoxon tests were used to compare before and after operation values. Indwelling voice prosthesis was found to improve quality of life, self-esteem, and sexual function (p < 0.05). Additionally, symptoms of depression and anxiety were regressed (p < 0.05). Indwelling voice prosthesis was found to especially increase the quality of life and decrease depression (p < 0.05). This study is an uncontrolled single-arm study comparing patients' psychosocial statuses pre- and post-voice prosthesis.

Effect of Framework in an Implant-Supported Full-Arch Fixed Prosthesis: 3D Finite Element Analysis.

PubMed

Menini, Maria; Pesce, Paolo; Bevilacqua, Marco; Pera, Francesco; Tealdo, Tiziano; Barberis, Fabrizio; Pera, Paolo

2015-01-01

The aim of this study was to analyze through a three-dimensional finite element analysis (3D-FEA) stress distribution on four implants supporting a full-arch implant-supported fixed prosthesis (FFP) using different prosthesis designs. A 3D edentulous maxillary model was created and four implants were virtually placed into the maxilla and splinted, simulating an FFP without framework, with a cast metal framework, and with a carbon fiber framework. An occlusal load of 150 N was applied, stresses were transmitted into peri-implant bone, and prosthodontic components were recorded. 3D-FEA revealed higher stresses on the implants (up to +55.16%), on peri-implant bone (up to +56.93%), and in the prosthesis (up to +70.71%) when the full-acrylic prosthesis was simulated. The prosthesis with a carbon fiber framework showed an intermediate behavior between that of the other two configurations. This study suggests that the presence of a rigid framework in full-arch fixed prostheses provides a better load distribution that decreases the maximum values of stress at the levels of implants, prosthesis, and maxillary bone.

Learning from demonstration: Teaching a myoelectric prosthesis with an intact limb via reinforcement learning.

PubMed

Vasan, Gautham; Pilarski, Patrick M

2017-07-01

Prosthetic arms should restore and extend the capabilities of someone with an amputation. They should move naturally and be able to perform elegant, coordinated movements that approximate those of a biological arm. Despite these objectives, the control of modern-day prostheses is often nonintuitive and taxing. Existing devices and control approaches do not yet give users the ability to effect highly synergistic movements during their daily-life control of a prosthetic device. As a step towards improving the control of prosthetic arms and hands, we introduce an intuitive approach to training a prosthetic control system that helps a user achieve hard-to-engineer control behaviours. Specifically, we present an actor-critic reinforcement learning method that for the first time promises to allow someone with an amputation to use their non-amputated arm to teach their prosthetic arm how to move through a wide range of coordinated motions and grasp patterns. We evaluate our method during the myoelectric control of a multi-joint robot arm by non-amputee users, and demonstrate that by using our approach a user can train their arm to perform simultaneous gestures and movements in all three degrees of freedom in the robot's hand and wrist based only on information sampled from the robot and the user's above-elbow myoelectric signals. Our results indicate that this learning-from-demonstration paradigm may be well suited to use by both patients and clinicians with minimal technical knowledge, as it allows a user to personalize the control of his or her prosthesis without having to know the underlying mechanics of the prosthetic limb. These preliminary results also suggest that our approach may extend in a straightforward way to next-generation prostheses with precise finger and wrist control, such that these devices may someday allow users to perform fluid and intuitive movements like playing the piano, catching a ball, and comfortably shaking hands.

Effects of separation of resources on behaviour, physical condition and production of laying hens in furnished cages.

PubMed

Shimmura, T; Azuma, T; Eguchi, Y; Uetake, K; Tanaka, T

2009-01-01

1. Based on our previous studies, we designed a medium-sized furnished cage with a dust bath and nest box on both sides of the cage (MFS) and evaluated its usefulness. 2. We used 180 White Leghorn layers. At the age of 17 weeks, the birds were distributed at random into one of the 4 cage designs: conventional cages (CC; 6 cages and 5 hens per cage), small (SF; 6 cages and 5 hens per cage) and medium furnished cages (MFL; 6 cages and 10 hens per cage) with a 'localised' dust bath and nest box on one side of the cage, and MFS (6 cages and 10 hens per cage). The total allocation of resources per bird was similar for all furnished cage designs. Behaviour, physical condition and production were measured in each cage. 3. Moving was more frequent in MFS and MFL than in CC and SF. The proportion of hens performing aggressive pecking and severe feather pecking was higher in MFL than CC and SF. These aggressive interactions occurred frequently in the dust bath area in MFL; however, these tendencies were not found in MFS. Egg production and egg mass were lower in MFL than in SF, while the production in MFS was similar to those in CC and SF. MFS hens laid eggs on the cage floor more often than in MFL. 4. In conclusion, these results demonstrate the possible usefulness of MFS. However, some inconsistent results and ways of improving MFS design were also identified.

Control and Evaluation of a Powered Transfemoral Prosthesis for Stair Ascent.

PubMed

Ledoux, Elissa D; Goldfarb, Michael

2017-07-01

This paper assesses the metabolic effort exerted by three transfemoral amputees, when using a powered knee and ankle prosthesis for stair ascent, relative to ascending stairs with passive knee and ankle prostheses. The paper describes a controller that provides step-over stair ascent behavior reflective of healthy stair ascent biomechanics, and describes its implementation in a powered prosthesis prototype. Stair ascent experiments were performed with three unilateral transfemoral amputee subjects, comparing the oxygen consumption required to ascend stairs using the powered prosthesis (with a step-over gait), relative to using their daily-use energetically passive prostheses (with a step-to gait). Results indicate on average a 24% reduction in oxygen consumption and a 30% reduction in stair ascent timewhen using the powered prosthesis, relative to when using the passive prostheses. All subjects expressed a strong preference for ascending stairs using the powered prosthesis.

Rehabilitation of orbital cavity after orbital exenteration using polymethyl methacrylate orbital prosthesis.

PubMed

Jain, Sumeet; Jain, Parul

2016-01-01

Squamous cell carcinoma of the eyelid is the second most common malignant neoplasm of the eye with the incidence of 0.09 and 2.42 cases/100 000 people. Orbital invasion is a rare complication but, if recognized early, can be treated effectively with exenteration. Although with advancements in technology such as computer-aided design and computer-aided manufacturing, material science, and retentive methods like implants, orbital prosthesis with stock ocular prosthesis made of methyl methacrylate retained by anatomic undercuts is quiet effective and should not be overlooked and forgotten. This clinical report describes prosthetic rehabilitation of two male patients with polymethyl methacrylate resin orbital prosthesis after orbital exenteration, for squamous cell carcinoma of the upper eyelid. The orbital prosthesis was sufficiently retained by hard and soft tissue undercuts without any complications. The patients using the prosthesis are quite satisfied with the cosmetic results and felt comfortable attending the social events.

Catastrophic metallosis after tumoral knee prosthesis failure: A case report.

PubMed

La Verde, Luca; Fenga, Domenico; Spinelli, Maria Silvia; Campo, Francesco Rosario; Florio, Michela; Rosa, Michele Attilio

2017-01-01

Metallosis is a condition characterized by an infiltration of periprosthetic soft tissues and bone by metallic debris resulting from wear or failure of joint arthroplasties. Authors describe a case of a 45-year-old man treated for an osteosarcoma of the distal femur with a modular prosthesis when he was 18 years old, he developed massive metallosis with skin dyspigmentation after 17 years. His medical\\surgical history was remarkable for a left tumoral knee prosthesis implanted 21 years ago. Two years before revision, the patient had a car accident with a two-points prosthesis breakage and despite the surgeon's advice, the patient refused surgery. In two years, prosthesis malfunction caused a progressive catastrophic soft tissues infiltration of metallic debris. Authors suggest that if prosthesis fracture is detected, revision surgery should be attempted as earlier as possible. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Microbial biofilms on facial prostheses.

PubMed

Ariani, Nina; Vissink, Arjan; van Oort, Robert P; Kusdhany, Lindawati; Djais, Ariadna; Rahardjo, Tri Budi W; van der Mei, Henny C; Krom, Bastiaan P

2012-01-01

The composition of microbial biofilms on silicone rubber facial prostheses was investigated and compared with the microbial flora on healthy and prosthesis-covered skin. Scanning electron microscopy showed the presence of mixed bacterial and yeast biofilms on and deterioration of the surface of the prostheses. Microbial culturing confirmed the presence of yeasts and bacteria. Microbial colonization was significantly increased on prosthesis-covered skin compared to healthy skin. Candida spp. were exclusively isolated from prosthesis-covered skin and from prostheses. Biofilms from prostheses showed the least diverse band-profile in denaturing gradient gel electrophoresis (DGGE) whereas prosthesis-covered skin showed the most diverse band-profile. Bacterial diversity exceeded yeast diversity in all samples. It is concluded that occlusion of the skin by prostheses creates a favorable niche for opportunistic pathogens such as Candida spp. and Staphylococcus aureus. Biofilms on healthy skin, skin underneath the prosthesis and on the prosthesis had a comparable composition, but the numbers present differed according to the microorganism.

Amputation and prosthesis implantation shape body and peripersonal space representations

PubMed Central

Canzoneri, Elisa; Marzolla, Marilena; Amoresano, Amedeo; Verni, Gennaro; Serino, Andrea

2013-01-01

Little is known about whether and how multimodal representations of the body (BRs) and of the space around the body (Peripersonal Space, PPS) adapt to amputation and prosthesis implantation. In order to investigate this issue, we tested BR in a group of upper limb amputees by means of a tactile distance perception task and PPS by means of an audio-tactile interaction task. Subjects performed the tasks with stimulation either on the healthy limb or the stump of the amputated limb, while wearing or not wearing their prosthesis. When patients performed the tasks on the amputated limb, without the prosthesis, the perception of arm length shrank, with a concurrent shift of PPS boundaries towards the stump. Conversely, wearing the prosthesis increased the perceived length of the stump and extended the PPS boundaries so as to include the prosthetic hand, such that the prosthesis partially replaced the missing limb. PMID:24088746

Efficacy of high doses of levofloxacin in experimental foreign-body infection by methicillin-susceptible Staphylococcus aureus.

PubMed

Murillo, O; Doménech, A; Garcia, A; Tubau, F; Cabellos, C; Gudiol, F; Ariza, J

2006-12-01

Antimicrobial efficacy in orthopedic device infections is diminished because of bacterial biofilms which express tolerance to antibiotics. Recently, the use of high doses of levofloxacin with rifampin has been recommended for staphylococcal infections. In the present study, we evaluated the efficacy of levofloxacin at doses of 50 mg/kg/day and 100 mg/kg/day (mimicking the usual and high human doses of 500 mg/day and 750 to 1,000 mg/day, respectively) and compared it to that of to linezolid, cloxacillin, vancomycin, and rifampin in a rat tissue cage model of experimental foreign-body infection by Staphylococcus aureus. The antimicrobial efficacy in vitro (by MIC, minimum bactericidal concentration, and kill curves) for logarithmic- and stationary-phase bacteria was compared with the in vivo efficacy. In vitro bactericidal activity at clinically relevant concentrations was reached by all drugs except rifampin and linezolid in the log-phase studies but only by levofloxacin in the stationary-phase studies. The bacterial count decreases from in vivo tissue cage fluids (means) for levofloxacin at 50 and 100 mg/kg/day, rifampin, cloxacillin, vancomycin, linezolid, and controls, respectively, were: -1.24, -2.26, -2.1, -1.56, -1.47, -1.15, and 0.33 (all groups versus controls, P < 0.05). Levofloxacin at 100 mg/kg/day (area under the concentration-time curve/MIC ratio, 234) was the most active therapy (P = 0.03 versus linezolid). Overall, in vivo efficacy was better predicted by stationary-phase studies, in which it reached a high correlation coefficient even if the rifampin group was excluded (r = 0.96; P < 0.05). Our results, including in vitro studies with nongrowing bacteria, pharmacodynamic parameters, and antimicrobial efficacy in experimental infection, provide good evidence to support the use of levofloxacin at high doses (750 to 1,000 mg/day), as recently recommended for treating patients with orthopedic prosthesis infections.

Development of a Mandibular Motion Simulator for Total Joint Replacement

PubMed Central

Celebi, Nukhet; Rohner, E. Carlos; Gateno, Jaime; Noble, Philip C.; Ismaily, Sabir K.; Teichgraeber, John F.; Xia, James J.

2015-01-01

Purpose The purpose of this study was to develop a motion simulator capable of recreating and recording the full range of mandibular motions in a cadaveric preparation for an intact temporomandibular joint (TMJ) and after total joint replacement. Material and Methods A human cadaver head was used. Two sets of tracking balls were attached to the forehead and mandible, respectively. Computed tomographic (CT) scan was performed and 3-dimensional CT models of the skull were generated. The cadaver head was then dissected to attach the muscle activation cables and mounted onto the TMJ simulator. Realistic jaw motions were generated through the application of the following muscle forces: lateral pterygoid muscle, suprahyoid depressors (geniohyoid, mylohyoid, and digastric muscles), and elevator muscles. To simulate muscle contraction, cables were inserted into the mandible at the center area of each muscle's attachment. To provide a minimum mouth closing force at the initial position, the elevator muscles were combined at the anterior mandible. During mandibular movement, each motion was recorded using a high-resolution laser scanner. The right TMJ of the same head was reconstructed with a total TMJ prosthesis. The same forces were applied and the jaw motions were recorded again. CT scan was performed and 3-dimensional CT models of the skull with TMJ prosthesis were generated. Results Mandibular motions, before and after TMJ replacement, with and without lateral pterygoid muscle reattachment, were re-created in a cadaveric preparation. The laser-scanned data during the mandibular motion were used to drive 3-dimensional CT models. A movie for each mandibular motion was subsequently created for motion path analysis. Compared with mandibular motion before TMJ replacement, mandibular lateral and protrusive motions after TMJ replacement, with and without lateral pterygoid muscle reattachment, were greatly limited. The jaw motion recorded before total joint replacement was applied to the mandibular and prostheses models after total TMJ replacement. The condylar component was observed sinking into the fossa during jaw motion. Conclusion A motion simulator capable of re-creating and recording full range of mandibular motions in a cadaveric preparation has been developed. It can be used to simulate mandibular motions for the intact TMJ and total joint prosthesis, and to re-create and record their full range of mandibular motions. In addition, the full range of the recorded motion can be re-created as motion images in a computer. These images can be used for motion path analysis and to study the causation of limited range of motion after total joint replacement and strategies for improvement. PMID:21050636

Polymers containing borane or carborane cage compounds and related applications

DOEpatents

Bowen, III, Daniel E; Eastwood, Eric A

2013-04-23

Polymers comprising residues of cage compound monomers having at least one polyalkoxy silyl substituent are provided. The cage compound monomers are selected from borane cage compound monomers comprising at least 7 cage atoms and/or carborane cage compound monomers comprising 7 to 11 cage compound monomers. Such polymers can further comprise one or more reactive matrices and/or co-monomers covalently bound with the cage compound monomer residues. Articles of manufacture comprising such polymers are also disclosed.

Carbon/PEEK composite materials as an alternative for stainless steel/titanium hip prosthesis: a finite element study.

PubMed

Rezaei, Farshid; Hassani, Kamran; Solhjoei, Nosratollah; Karimi, Alireza

2015-12-01

Total hip replacement (THR) has been ranked within the most typical surgical processes in the world. The durability of the prosthesis and loosening of prosthesis are the main concerns that mostly reported after THR surgeries. In THR, the femoral prosthesis can be fixed by either cement or cementless methods in the patient's bones. In both procedures, the stability of the prosthesis in the hosted bone has a key asset in its long-term durability and performance. This study aimed to execute a comparative finite element simulation to assess the load transfer between the prosthesis, which is made of carbon/PEEK composite and stainless steel/titanium, and the femur bone. The mechanical behavior of the cortical bone was assumed as a linear transverse isotropic while the spongy bone was modeled like a linear isotropic material. The implants were made of stainless steel (316L) and titanium alloy as they are common materials for implants. The results showed that the carbon/PEEK composites provide a flatter load transfer from the upper body to the leg compared to the stainless steel/titanium prosthesis. Furthermore, the results showed that the von Mises stress, principal stress, and the strain in the carbon/PEEK composites prosthesis were significantly lower than that made of the stainless steel/titanium. The results also imply that the carbon/PEEK composites can be applied to introduce a new optimum design for femoral prosthesis with adjustable stiffness, which can decrease the stress shielding and interface stress. These findings will help clinicians and biomedical experts to increase their knowledge about the hip replacement.

Development and performance of a new prosthesis system using ultrasonic sensor for wrist movements: a preliminary study

PubMed Central

2014-01-01

Background The design and performance of a new development prosthesis system known as biomechatronics wrist prosthesis is presented in this paper. The prosthesis system was implemented by replacing the Bowden tension cable of body powered prosthesis system using two ultrasonic sensors, two servo motors and microcontroller inside the prosthesis hand for transradial user. Methods The system components and hand prototypes involve the anthropometry, CAD design and prototyping, biomechatronics engineering together with the prosthetics. The modeler construction of the system develop allows the ultrasonic sensors that are placed on the shoulder to generate the wrist movement of the prosthesis. The kinematics of wrist movement, which are the pronation/supination and flexion/extension were tested using the motion analysis and general motion of human hand were compared. The study also evaluated the require degree of detection for the input of the ultrasonic sensor to generate the wrist movements. Results The values collected by the vicon motion analysis for biomechatronics prosthesis system were reliable to do the common tasks in daily life. The degree of the head needed to bend to give the full input wave was about 45° - 55° of rotation or about 14 cm – 16 cm. The biomechatronics wrist prosthesis gave higher degree of rotation to do the daily tasks but did not achieve the maximum degree of rotation. Conclusion The new development of using sensor and actuator in generating the wrist movements will be interesting for used list in medicine, robotics technology, rehabilitations, prosthetics and orthotics. PMID:24755242

Virtual transplantation in designing a facial prosthesis for extensive maxillofacial defects that cross the facial midline using computer-assisted technology.

PubMed

Feng, Zhi-hong; Dong, Yan; Bai, Shi-zhu; Wu, Guo-feng; Bi, Yun-peng; Wang, Bo; Zhao, Yi-min

2010-01-01

The aim of this article was to demonstrate a novel approach to designing facial prostheses using the transplantation concept and computer-assisted technology for extensive, large, maxillofacial defects that cross the facial midline. The three-dimensional (3D) facial surface images of a patient and his relative were reconstructed using data obtained through optical scanning. Based on these images, the corresponding portion of the relative's face was transplanted to the patient's where the defect was located, which could not be rehabilitated using mirror projection, to design the virtual facial prosthesis without the eye. A 3D model of an artificial eye that mimicked the patient's remaining one was developed, transplanted, and fit onto the virtual prosthesis. A personalized retention structure for the artificial eye was designed on the virtual facial prosthesis. The wax prosthesis was manufactured through rapid prototyping, and the definitive silicone prosthesis was completed. The size, shape, and cosmetic appearance of the prosthesis were satisfactory and matched the defect area well. The patient's facial appearance was recovered perfectly with the prosthesis, as determined through clinical evaluation. The optical 3D imaging and computer-aided design/computer-assisted manufacturing system used in this study can design and fabricate facial prostheses more precisely than conventional manual sculpturing techniques. The discomfort generally associated with such conventional methods was decreased greatly. The virtual transplantation used to design the facial prosthesis for the maxillofacial defect, which crossed the facial midline, and the development of the retention structure for the eye were both feasible.

Effect of housing arrangement on fecal-oral transmission of avian hepatitis E virus in chicken flocks.

PubMed

Liu, Baoyuan; Sun, Yani; Chen, Yiyang; Du, Taofeng; Nan, Yuchen; Wang, Xinjie; Li, Huixia; Huang, Baicheng; Zhang, Gaiping; Zhou, En-Min; Zhao, Qin

2017-09-07

Avian hepatitis E virus (HEV) infection is common in chicken flocks in China, as currently no measures exist to prevent the spread of the disease. In this study, we analyzed the effect of caged versus cage-free housing arrangements on avian HEV transmission. First, 127 serum and 110 clinical fecal samples were collected from 4 chicken flocks including the two arrangements in Shaanxi Province, China and tested for HEV antibodies and/or virus. Concurrently, 36 specific-pathogen-free chickens were divided equally into four experimental living arrangement groups, designated cage-free (Inoculated), caged (Inoculated), cage-free (Negative) and caged (Negative) groups. In caged groups, three cages contained 3 chickens each. Three chickens each from cage-free (Inoculated) and caged (Inoculated) groups (one chicken of each cage) were inoculated by cutaneous ulnar vein with the same dose of avian HEV, respectively. The cage-free (Negative) and caged (Negative) groups served as negative control. Serum and fecal samples were collected at 1 to 7 weeks post-inoculation (wpi) and liver lesions were scored at 7 wpi. The results of serology showed that the avian HEV infection rate (54.10%) of the cage-free chickens was significantly higher than the one (12.12%) for caged chickens (P < 0.05). Also, the rate of detection of avian HEV RNA in the clinical fecal samples was significantly higher in the cage-free (22.80%, 13/57) than caged birds (5.66%, 3/53). Moreover, under experimental conditions, the infected number of uninoculated cage-free chickens (6) was significantly higher than the one for the uninoculated caged birds (2), as evidenced by seroconversion, fecal virus shedding, viremia and gross and microscopic liver lesions. These results suggest that reduction of contact with feces as seen in the caged arrangement of housing chickens can reduce avian HEV transmission. This study provides insights for prevention and control of avian HEV infection in chicken flocks.

[The influence of the stapes prosthesis on the long-term results of stapedectomy (author's transl)].

PubMed

Schöndorf, J; Pilorget, J; Gräber, S

1980-05-01

In comparing two groups of patients following stapedectomies, significantly better long-term results were obtained by using the Robinson steel piston prosthesis (n = 85) as opposed to the wire prosthesis (n = 74). By so doing, the impairment of sound transmission was reduced and the Carhart depression counterbalanced. This improvement is thought to result from the increased mass and stability of the steel prosthesis as well as from its more correct anatomical positioning.

Functional Performance Evaluation of the Northwestern University Flexible Subischial Vacuum (NU-FlexSIV) Socket for Persons with Transfemoral Amputation

DTIC Science & Technology

2016-10-01

satisfaction with device’’ (i.e. prosthesis) than the IC Socket. During year 1, we received all required IRB approvals, registered the clinical... satisfaction with device” (i.e. prosthesis) than the IC Socket. 2. KEYWORDS: Prosthetic Socket, Artificial Limbs, Prosthesis, Transfemoral Amputee, Gait...FlexSIV Socket will result in better quality of life and “ satisfaction with device” (i.e. prosthesis) than the IC socket. Accomplishments under

Categorization of compensatory motions in transradial myoelectric prosthesis users.

PubMed

Hussaini, Ali; Zinck, Arthur; Kyberd, Peter

2017-06-01

Prosthesis users perform various compensatory motions to accommodate for the loss of the hand and wrist as well as the reduced functionality of a prosthetic hand. Investigate different compensation strategies that are performed by prosthesis users. Comparative analysis. A total of 20 able-bodied subjects and 4 prosthesis users performed a set of bimanual activities. Movements of the trunk and head were recorded using a motion capture system and a digital video recorder. Clinical motion angles were calculated to assess the compensatory motions made by the prosthesis users. The video recording also assisted in visually identifying the compensations. Compensatory motions by the prosthesis users were evident in the tasks performed (slicing and stirring activities) as compared to the benchmark of able-bodied subjects. Compensations took the form of a measured increase in range of motion, an observed adoption of a new posture during task execution, and prepositioning of items in the workspace prior to initiating a given task. Compensatory motions were performed by prosthesis users during the selected tasks. These can be categorized into three different types of compensations. Clinical relevance Proper identification and classification of compensatory motions performed by prosthesis users into three distinct forms allows clinicians and researchers to accurately identify and quantify movement. It will assist in evaluating new prosthetic interventions by providing distinct terminology that is easily understood and can be shared between research institutions.

Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses.

PubMed

Schuhbaeck, Annika; Weingartner, Christina; Arnold, Martin; Schmid, Jasmin; Pflederer, Tobias; Marwan, Mohamed; Rixe, Johannes; Nef, Holger; Schneider, Christian; Lell, Michael; Uder, Michael; Ensminger, Stephan; Feyrer, Richard; Weyand, Michael; Achenbach, Stephan

2015-07-01

The geometry of the aortic annulus and implanted transcatheter aortic valve prosthesis might influence valve function. We investigated the influence of valve type and aortic valve calcification on post-implant geometry of catheter-based aortic valve prostheses. Eighty consecutive patients with severe aortic valve stenosis (mean age 82 ± 6 years) underwent computed tomography before and after TAVI. Aortic annulus diameters were determined. Influence of prosthesis type and degree of aortic valve calcification on post-implant eccentricity were analysed. Aortic annulus eccentricity was reduced in patients after TAVI (0.21 ± 0.06 vs. 0.08 ± 0.06, p<0.0001). Post-TAVI eccentricity was significantly lower in 65 patients following implantation of a balloon-expandable prosthesis as compared to 15 patients who received a self-expanding prosthesis (0.06 ± 0.05 vs. 0.15 ± 0.07, p<0.0001), even though the extent of aortic valve calcification was not different. After TAVI, patients with a higher calcium amount retained a significantly higher eccentricity compared to patients with lower amounts of calcium. Patients undergoing TAVI with a balloon-expandable prosthesis show a more circular shape of the implanted prosthesis as compared to patients with a self-expanding prosthesis. Eccentricity of the deployed prosthesis is affected by the extent of aortic valve calcification. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Improvements in survival of the uncemented Nottingham Total Shoulder prosthesis: a prospective comparative study

PubMed Central

Rosenberg, Nahum; Neumann, Lars; Modi, Amit; Mersich, Istvan J; Wallace, Angus W

2007-01-01

Background The uncemented Nottingham Total Shoulder Replacement prosthesis system (Nottingham TSR) was developed from the previous BioModular® shoulder prosthesis taking into consideration the causes of the initial implant's failure. We investigated the impact of changes in the design of Nottingham TSR prosthesis on its survivorship rate. Methods Survivorship analyses of three types of uncemented total shoulder arthroplasty prostheses (BioModular®, initial Nottingham TSR and current Nottingham TSR systems with 11, 8 and 4 year survivorship data respectively) were compared. All these prostheses were implanted for the treatment of disabling pain in the shoulder due to primary and secondary osteoarthritis or rheumatoid arthritis. Each type of the prosthesis studied was implanted in consecutive group of patients – 90 patients with BioModular® system, 103 with the initial Nottingham TSR and 34 patients with the current Nottingham TSR system. The comparison of the annual cumulative survivorship values in the compatible time range between the three groups was done according to the paired t test. Results The 8-year and 11-year survivorship rates for the initially used modified BioModular® uncemented prosthesis were relatively low (75.6% and 71.7% respectively) comparing to the reported survivorship of the conventional cemented implants. The 8-year survivorship for the uncemented Nottingham TSR prosthesis was significantly higher (81.8%), but still not in the desired range of above 90%, that is found in other cemented designs. Glenoid component loosening was the main factor of prosthesis failure in both prostheses and mainly occurred in the first 4 postoperative years. The 4-year survivorship of the currently re-designed Nottingham TSR prosthesis, with hydroxylapatite coating of the glenoid baseplate, was significantly higher, 93.1% as compared to 85.1% of the previous Nottingham TSR. Conclusion The initial Nottingham shoulder prosthesis showed significantly higher survivorship than the BioModular® uncemented prosthesis, but lower than expected. Subsequently re-designed Nottingham TSR system presented a high short term survivorship rate that encourages its ongoing use PMID:17683577

Protein cage assembly across multiple length scales.

PubMed

Aumiller, William M; Uchida, Masaki; Douglas, Trevor

2018-05-21

Within the materials science community, proteins with cage-like architectures are being developed as versatile nanoscale platforms for use in protein nanotechnology. Much effort has been focused on the functionalization of protein cages with biological and non-biological moieties to bring about new properties of not only individual protein cages, but collective bulk-scale assemblies of protein cages. In this review, we report on the current understanding of protein cage assembly, both of the cages themselves from individual subunits, and the assembly of the individual protein cages into higher order structures. We start by discussing the key properties of natural protein cages (for example: size, shape and structure) followed by a review of some of the mechanisms of protein cage assembly and the factors that influence it. We then explore the current approaches for functionalizing protein cages, on the interior or exterior surfaces of the capsids. Lastly, we explore the emerging area of higher order assemblies created from individual protein cages and their potential for new and exciting collective properties.

Microclimatic Variation Within Sleeve Cages Used in Ecological Studies

PubMed Central

Nelson, Lori A.; Rieske, Lynne K.

2014-01-01

Abstract Sleeve cages for enclosing or excluding arthropods are essential components of field studies evaluating trophic interactions. Microclimatic variation in sleeve cages was evaluated to characterize its potential effects on subsequent long-term experiments. Two sleeve cage materials, polyester and nylon, and two cage sizes, 400 and 6000 cm 2 , were tested on eastern hemlock, Tsuga canadensis (L.) Carrière. Temperature and relative humidity inside and outside cages, and the cost and durability of the cage materials, were compared. Long-term effects of the sleeve cages were observed by measuring new growth on T. canadensis branches. The ultimate goal was to identify a material that minimizes bag-induced microclimatic variation. Bagged branches whose microclimates mimic those of surrounding unbagged branches should have minimal effects on plant growth and may prove ideal venues for assessing herbivore and predator behavior under natural conditions. No differences were found in temperature or humidity between caging materials. Small cages had higher average temperatures than large cages, especially in the winter, but this difference was confounded by the fact that small cages were positioned higher in trees than large cages. Differences in plant growth were detected. Eastern hemlock branches enclosed within polyester cages produced fewer new growth tips than uncaged controls. Both polyester and nylon cages reduced the length of new shoot growth relative to uncaged branches. In spite of higher costs, nylon cages were superior to polyester with respect to durability and ease of handling. PMID:25368083

Science of Ball Lightning (Fire Ball)

NASA Astrophysics Data System (ADS)

Ohtsuki, Yoshi-Hiko

1989-08-01

The Table of Contents for the full book PDF is as follows: * Organizing Committee * Preface * Ball Lightning -- The Continuing Challenge * Hungarian Ball Lightning Observations in 1987 * Nature of Ball Lightning in Japan * Phenomenological and Psychological Analysis of 150 Austrian Ball Lightning Reports * Physical Problems and Physical Properties of Ball Lightning * Statistical Analysis of the Ball Lightning Properties * A Fluid-Dynamical Model for Ball Lightning and Bead Lightning * The Lifetime of Hill's Vortex * Electrical and Radiative Properties of Ball Lightning * The Candle Flame as a Model of Ball Lightning * A Model for Ball Lightning * The High-Temperature Physico-Chemical Processes in the Lightning Storm Atmosphere (A Physico-Chemical Model of Ball Lightning) * New Approach to Ball Lightning * A Calculation of Electric Field of Ball Lightning * The Physical Explanation to the UFO over Xinjiang, Northern West China * Electric Reconnection, Critical Ionization Velocity, Ponderomotive Force, and Their Applications to Triggered and Ball Lightning * The PLASMAK™ Configuration and Ball Lightning * Experimental Research on Ball Lightning * Performance of High-Voltage Test Facility Designed for Investigation of Ball Lightning * List of Participants

Ball Screw Actuator Including a Compliant Ball Screw Stop

NASA Technical Reports Server (NTRS)

Wingett, Paul T. (Inventor); Hanlon, Casey (Inventor)

2015-01-01

An actuator includes a ball nut, a ball screw, and a ball screw stop. The ball nut is adapted to receive an input torque and in response rotates and supplies a drive force. The ball screw extends through the ball nut and has a first end and a second end. The ball screw receives the drive force from the ball nut and in response selectively translates between a retract position and a extend position. The ball screw stop is mounted on the ball screw proximate the first end to translate therewith. The ball screw stop engages the ball nut when the ball screw is in the extend position, translates, with compliance, a predetermined distance toward the first end upon engaging the ball nut, and prevents further rotation of the ball screw upon translating the predetermined distance.

Ball Screw Actuator Including a Compliant Ball Screw Stop

NASA Technical Reports Server (NTRS)

Wingett, Paul T. (Inventor); Hanlon, Casey (Inventor)

2017-01-01

An actuator includes a ball nut, a ball screw, and a ball screw stop. The ball nut is adapted to receive an input torque and in response rotates and supplies a drive force. The ball screw extends through the ball nut and has a first end and a second end. The ball screw receives the drive force from the ball nut and in response selectively translates between a retract position and a extend position. The ball screw stop is mounted on the ball screw proximate the first end to translate therewith. The ball screw stop engages the ball nut when the ball screw is in the extend position, translates, with compliance, a predetermined distance toward the first end upon engaging the ball nut, and prevents further rotation of the ball screw upon translating the predetermined distance.

Comparative experimental re-evaluation of the two implanting methods of silicone gel testicular prostheses in beagle dogs

PubMed Central

2011-01-01

Background Testicular prosthesis has been applied clinically for decades, and implantation of testis prosthesis under the tunica albuginea has been considered to be the standard method in the most of the reports. However, postoperative scrotal appearance, the mobilization and the palpitation of the prosthesis are not always satisfactory to all the patients. Modifications in surgical techniques might be necessary to bring improvements to the clinical outcomes in testicular prosthesis implantation. Findings In a group of 9 beagle dogs in this study, an orchiectomy succeeded with a testicular prosthesis implantation under the tunica vaginalis, and a complete mechanical denudation of the testicular parenchyma succeeded with an implantation under the tunica albuginea were performed, respectively. Histopathological evaluations of the scrotal tissues and the implants, which were made at the end of the follow-up, showed that all the tested animals lived uneventful lives during the follow-up period, and no rejections or infections were found. Prostheses implanted under the tunica vaginalis showed a more satisfying mobilization and palpation than those implanted under the tunica albuginea. Chronic inflammation in the para-prosthesis tissues with vascular proliferation and fibrinogenesis were more common in the "under tunica albuginea" group than that in the "under tunica vaginalis" group, although differences in fibrinogenesis between the two groups were found to be statistically insignificant. Conclusions In this comparative study, we have re-evaluated the two most popular implantation methods of testicular prosthesis, the "under the tunica albuginea" and the "under the tunica vaginalis" pathways, in animal models. We found that the testicular prosthesis were all well tolerated, but the prosthesis implanted under the tunica vaginalis showed a more satisfying result concerning appearance, palpability, and histopathological findings than that of the "under the tunica albuginea" group. The "under the tunica vaginalis" method might become a more practical method for future testicular prosthesis implantation. PMID:21457571

[Imaging evaluation on adaptability of proximal humeral anatomy after shoulder replacement with individualized shoulder prosthesis].

PubMed

Shi, Youxing; Tang, Kanglai; Yuan, Chengsong; Tao, Xu; Wang, Huaqing; Chen, Bo; Guo, Yupeng

2015-03-24

Modern shoulder prosthesis has evolved through four generations. And the fourth generation technology has a core three-dimensional design of restoring 3D reconstruction of proximal humeral anatomy. Thus a new shoulder prosthesis is developed on the basis of the technology of 3D prosthesis. Assessment of whether shoulder prosthesis can restore individualized reconstruction of proximal humeral anatomy is based on the adaptability of proximal humeral anatomy. To evaluate the adaptability of proximal humeral anatomy through measuring the parameters of proximal humeral anatomy after shoulder replacement with individualized shoulder prosthesis and compare with normal data. The parameters of proximal humeral anatomy were analyzed and evaluated for a total of 12 cases undergoing shoulder replacement with individualized shoulder prosthesis. The relevant anatomical parameters included neck-shaft angle (NSA), retroversion angle (RA), humeral head height (HH) and humeral head diameter (HD). And the anatomical parameters were compared with the data from normal side. All underwent shoulder replacement with individualized shoulder prosthesis. The postoperative parameters of proximal humeral anatomy were compared with those of normal side. And the difference of NSA was < 3°, RA < 3°, HH < 3 mm and HD < 2 mm. And paired-sample t test was used to study the parameters of proximal humeral anatomy between postoperative and normal side. The normal and postoperative NSA was (140.2 ± 6.8)° and (139.5 ± 6.6)° respectively, RA (34.4 ± 3.3)° and (33.8-3.1)°, HH (15.3 ± 2.1) mm and (14.6+0.9) mm, HW (42.2 ± 2.82) mm and (41.8 ± 2.33) mm respectively. No significant difference existed between two groups (P > 0.05). Individualized shoulder prosthesis has excellent adaptability to shoulder. All core parameters are freely adjustable and specification models may be optimized. With matching tools, individualized shoulder prosthesis improves the accuracy and reliability in shoulder replacement.

A custom-made temporomandibular joint prosthesis for fabrication by selective laser melting: Finite element analysis.

PubMed

Xu, Xiangliang; Luo, Danmei; Guo, Chuanbin; Rong, Qiguo

2017-08-01

A novel and custom-made selective laser melting (SLM) 3D-printed alloplastic temporomandibular joint (TMJ) prosthesis is proposed. The titanium-6aluminium-4vanadium (Ti-6Al-4V) condyle component and ultra-high molecular weight polyethylene (UHMWPE) fossa component comprised the total alloplastic TMJ replacement prosthesis. For the condyle component, an optimized tetrahedral open-porous scaffold with combined connection structures, i.e. an inlay rod and an onlay plate, between the prosthesis and remaining mandible was designed. The trajectory of movement of the intact condyle was assessed via kinematic analysis to facilitate the design of the fossa component. The behaviours of the intact mandible and mandible with the prosthesis were compared. The biomechanical behaviour was analysed by assessing the stress distribution on the prosthesis and strain distribution on the mandible. After muscle force was applied, the magnitude of the compressive strain on the condyle neck of the mandible with the prosthesis was lower than that on the condyle neck of the intact mandible, with the exception of the area about the screws; additionally, the magnitude of the strain at the scaffold-bone interface was relatively high. Copyright © 2017. Published by Elsevier Ltd.

Evaluation of direct and indirect additive manufacture of maxillofacial prostheses.

PubMed

Eggbeer, Dominic; Bibb, Richard; Evans, Peter; Ji, Lu

2012-09-01

The efficacy of computer-aided technologies in the design and manufacture of maxillofacial prostheses has not been fully proven. This paper presents research into the evaluation of direct and indirect additive manufacture of a maxillofacial prosthesis against conventional laboratory-based techniques. An implant/magnet-retained nasal prosthesis case from a UK maxillofacial unit was selected as a case study. A benchmark prosthesis was fabricated using conventional laboratory-based techniques for comparison against additive manufactured prostheses. For the computer-aided workflow, photogrammetry, computer-aided design and additive manufacture (AM) methods were evaluated in direct prosthesis body fabrication and indirect production using an additively manufactured mould. Qualitative analysis of position, shape, colour and edge quality was undertaken. Mechanical testing to ISO standards was also used to compare the silicone rubber used in the conventional prosthesis with the AM material. Critical evaluation has shown that utilising a computer-aided work-flow can produce a prosthesis body that is comparable to that produced using existing best practice. Technical limitations currently prevent the direct fabrication method demonstrated in this paper from being clinically viable. This research helps prosthesis providers understand the application of a computer-aided approach and guides technology developers and researchers to address the limitations identified.

[The endo-exo femur prosthesis--a new concept of bone-guided, prosthetic rehabilitation following above-knee amputation].

PubMed

Aschoff, H H; Clausen, A; Hoffmeister, T

2009-01-01

The implantation of an intramedullary transcutaneously conducted femur prosthesis presents a rather new procedure for the rehabilitation of above-knee amputated patients. The aim of the so-called endo-exo prosthesis is to avoid the well-known problems at the interface between the sleeve of the prosthesis and the soft tissue coat of the femur stump which often impedes an inconspicuous and harmonic gait. The company ERSKA Implants in Lübeck/Germany has developed an intramedullary femur prosthesis with a spongiosa metal-configurated relief surface which, when implanted cementless, enables a secure osseointegration and allows a more direct transmission of muscle power to the lower leg prosthesis. A minimum length of 16-18 cm and a sufficient soft tissue coverage of the femur stump is needed. The problems at the perforation point of the implant through the soft tissue coat can be handled or even be avoided and they do not necessarily provoke an intramedullary infection. We report on 30 cases that were operated between 1999 and 2008. The design of the prosthesis, aspects of the operative procedure and latest results are presented.

Evaluation of a new composite prosthesis for the repair of abdominal wall defects.

PubMed

Losi, Paola; Munaò, Antonella; Spiller, Dario; Briganti, Enrica; Martinelli, Ilaria; Scoccianti, Marco; Soldani, Giorgio

2007-10-01

The degree of integration of biomaterials used in the repair of abdominal wall defects seems to depend upon the structure of the prosthesis. The present investigation evaluates the behaviour in terms of adhesion formation and integration of a new composite prosthesis that could be employed in this clinical application. Full-thickness abdominal wall defects (7 x 5 cm) were created in 16 anaesthetized New Zealand white rabbits and the prosthesis were placed in direct contact with the visceral peritoneum during the experiment. The defects were repaired with a composite prosthesis or pure polypropylene mesh to establish two study groups (n = 8 each). The composite device was constituted by a polypropylene mesh physically attached to a poly(ether)urethane-polydimethylsiloxane laminar sheet. Animals were sacrificed 7, 14, 21 and 30 days after implant and prosthesis/surrounding tissue specimens subjected to light and electron microscopy. Firm adhesions were detected in the polypropylene implants, while they were not present in the composite implants. The excellent behaviour of the composite prosthesis shown in this study warrants further investigation on its use for the repair of abdominal wall defects when a prosthetic device needs to be placed in contact with the intestinal loops.

Linking of total elbow prosthesis during surgery; a biomechanical analysis.

PubMed

De Vos, Maarten J; Wagener, Marc L; Hendriks, Jan C M; Eygendaal, Denise; Verdonschot, Nico

2013-09-01

Presently, 2 types of elbow prostheses are used: unlinked and linked. The Latitude total elbow prosthesis allows the surgeon to decide during the implantation whether the prosthesis is placed unlinked or linked, and whether the native radial head is retained, resected, or replaced. The purpose of this study is to assess and to compare the varus and valgus laxity of the unlinked and linked version of the latitude total elbow prosthesis with: (1) the native radial head preserved, (2) the native radial head excised, and (3) the native radial head replaced by a radial head component. Biomechanical testing was performed on 14 fresh-frozen upper limb specimens. Linking the prosthesis predominantly influences the valgus laxity of the elbow. Linking the Latitude total elbow prosthesis results in increased valgus stability. In the linked version of the total elbow prosthesis, the radial head only plays a small part in both valgus and varus stability. An unlinked situation is not advised in absence of a native radial head or in case of inability to replace the radial head. Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

[Osseointegration as a method of direct stabilization of amputation prostheses to the bone].

PubMed

Rochmiński, Robert; Sibński, Marcin; Synder, Marek

2011-01-01

This article summarizes important advantages, disadvantages and the process of treatment of patients after lower limb amputation on the level of the femur, with osseointegrated prosthesis. In the process of treatment bone-integrated material is implanted to the femur, with allows for structural and functional connection between live tissue and the prosthesis. This solution allows the patient for easy usage and direct steerage of the prosthesis, transferring of body weight to the floor and detection of sensation in the moment of contact between prosthesis and the ground. Osseointegrated prostheses in the femur gives the opportunity not to use the traditional solutions and socket-related problems as: mobility difficulties, skin sores, rush, pain during weight bearing, temporary changes of the stump volume, difficulty donning the prosthesis, unreliability of prosthesis being securely suspended. Osseointegration is possible even in cases, when quality of skin and short stump enables to use the traditional prosthetic socket. It is used after lower and upper limbs amputations. This kind of prosthetic solutions has some disadvantages and limitations. It is expensive and demanding. It can be used in cooperative patients, who take active part in the process of implantation, rehabilitation and in future usage if the prosthesis.

"Bail out" procedures for malpositioning of aortic valve prosthesis (CoreValve).

PubMed

Vavouranakis, Manolis; Vrachatis, Dimitrios A; Toutouzas, Konstantinos P; Chrysohoou, Christina; Stefanadis, Christodoulos

2010-11-05

Two techniques for correcting malpositioning occurring during percutaneous aortic valve replacement (PAVR) with the CoreValve ReValving™ System are described in this article. The "Removing and Reinserting Technique" was used in 2 patients, in whom the prosthesis was positioned too high. The "Snare Technique" was used in 1 patient, in whom the prosthesis was implanted too low. In all patients the aortic valve prosthesis was successfully re-implanted. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

A fiber-reinforced composite prosthesis restoring a lateral midfacial defect: a clinical report.

PubMed

Kurunmäki, Hemmo; Kantola, Rosita; Hatamleh, Muhanad M; Watts, David C; Vallittu, Pekka K

2008-11-01

This clinical report describes the use of a glass fiber-reinforced composite (FRC) substructure to reinforce the silicone elastomer of a large facial prosthesis. The FRC substructure was shaped into a framework and embedded into the silicone elastomer to form a reinforced facial prosthesis. The prosthesis is designed to overcome the disadvantages associated with traditionally fabricated prostheses; namely, delamination of the silicone of the acrylic base, poor marginal adaptation over time, and poor simulation of facial expressions.

Negative Gauge Pressure Moisture Management and Secure Adherence Device for Prosthetic Limbs

DTIC Science & Technology

2013-03-01

prosthesis feels like it is sliding up and down or falling off when I am active. D. I have been more active than normal as a result of this prosthesis ...temperature. 3. My prosthesis feels like it is sliding up and down or falling off when I am active. 4. I have been more active than normal as a result of...objective of this research was to develop and test a novel prosthesis incorporating a negative gauge pressure moisture management and secure

Development and Application of a Tendon Prosthesis for Early Functional Restoration of the Hand.

DTIC Science & Technology

1975-09-01

F’A-AOk 322 JEFFERSON MEDICAL COLL PHILADELPHIA PA F/B 6/5 DEVELOPMENT AND APPLICATION OF A TENDON PROSTHESIS FOR EARLY FU--ETC(U) SEP 75 J M HUNTER...LEVEL INVENTORY DEELOPKWTI AND APPLICATION OF A TENDON PROSTHESIS FOR EARLY FUNCTIOKAL RESTORATION OF THE RAND BIDETICATION DISTRIBUTION STATEMENT A...AND RETURN TO DTIC-DDA-2 FORM DOCUMENT PROCESSING SHEETCToc 79 0 AD DEVELOPNDT AND APPLICATION OF A TENDOR PROSTHESIS FOR EARLY FUNCTIONAL

Computational comparison of three posterior lumbar interbody fusion techniques by using porous titanium interbody cages with 50% porosity.

PubMed

Lee, Yung-Heng; Chung, Chi-Jen; Wang, Chih-Wei; Peng, Yao-Te; Chang, Chih-Han; Chen, Chih-Hsien; Chen, Yen-Nien; Li, Chun-Ting

2016-04-01

This study investigated the biomechanical response of porous cages and lumbar spine segments immediately after surgery and after bone fusion, in addition to the long-term effects of various posterior lumbar interbody fusion (PLIF) techniques, by using the finite element method. Lumbar L3-L4 models based on three PLIF techniques (a single cage at the center of the intervertebral space, a single cage half-anterior to the intervertebral space, and two cages bilateral to the intervertebral space) with and without bone ingrowth were used to determine the biomechanical response of porous cages and lumbar segments instrumented with porous titanium cages (cage porosity=50%, pore diameter=1mm). The results indicated that bone fusion enhanced the stability of the lumbar segments with porous cages without any posterior instrumentation and reduced the peak von Mises stress in the cortical bones and porous cages. Two cages placed bilateral to the intervertebral space achieved the highest structural stability in the lumbar segment and lowest von Mises stress in the cages under both bone fusion conditions. Under identical loading (2-Nm), the range of motion in the single cage at the center of the intervertebral space with bone fusion decreased by 11% (from 1.18° to 1.05°) during flexion and by 66.5% (from 4.46° to 1.5°) during extension in the single cage half-anterior to the intervertebral space with bone fusion compared with no-fusion models. Thus, two porous titanium cages with 50% porosity can achieve high stability of a lumbar segment with PLIF. If only one cage is available, placing the cage half-anterior to the intervertebral space is recommended for managing degenerated lumbar segments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Do position and size matter? An analysis of cage and placement variables for optimum lordosis in PLIF reconstruction.

PubMed

Landham, Priyan R; Don, Angus S; Robertson, Peter A

2017-11-01

To examine monosegmental lordosis after posterior lumbar interbody fusion (PLIF) surgery and relate lordosis to cage size, shape, and placement. Eighty-three consecutive patients underwent single-level PLIF with paired identical lordotic cages involving a wide decompression and bilateral facetectomies. Cage parameters relating to size (height, lordosis, and length) and placement (expressed as a ratio relative to the length of the inferior vertebral endplate) were recorded. Centre point ratio (CPR) was the distance to the centre of both cages and indicated mean position of both cages. Posterior gap ratio (PGR) was the distance to the most posterior cage and indicated position and cage length indirectly. Relationships between lordosis and cage parameters were explored. Mean lordosis increased by 5.98° (SD 6.86°). The cages used varied in length from 20 to 27 mm, in lordosis from 10° to 18°, and in anterior cage height from 10 to 17 mm. The mean cage placement as determined by CPR was 0.54 and by PGR was 0.16. The significant correlations were: both CPR and PGR with lordosis gain at surgery (r = 0.597 and 0.537, respectively, p < 0.001 both), cage lordosis with the final lordosis (r = 0.234, p < 0.05), and anterior cage height was negatively correlated with a change in lordosis (r = -0.297, p < 0.01). Cage size, shape, and position, in addition to surgical technique, determine lordosis during PLIF surgery. Anterior placement with sufficient "clear space" behind the cages is recommended. In addition, cages should be of moderate height and length, so that they act as an effective pivot for lordosis.

Development of hydroxyapatite/polyvinyl alcohol bionanocomposite for prosthesis implants

NASA Astrophysics Data System (ADS)

Karthik, V.; Pabi, S. K.; Chowdhury, S. K. Roy

2018-02-01

Hydroxyapatite (Ca10(PO4)6(OH)2) has similar structural and chemical properties of natural bone mineral and hence widely used as a bone replacement substitute. Natural bone consists of hydroxyapatite and collagen. For mimicking the natural, in the present work, a sintered porous hydroxyapatite component has been vacuum impregnated with Polyvinyl alcohol (PVA), which has better properties like biocompatibility, biodegradability and water- solubility. Hydroxyapatite powders have been made into nanosize to reduce the melting point and hence the sintering temperature. In the present investigation high energy ball mill is used to produce nano-hydroxyapatite powders in bulk quantity by optimizing the milling parameters using stainless steel grinding media. Pellets of 10 mm diameter have been produced from nano- hydroxyapatite powders under different uniaxial compaction pressures. The pellets have been sintered to form porous compacts. The vacuum impregnation of sintered pallets with PVA solution of different strength has been done to find the optimum impregnation condition. Microhardness, compressive strength, wear loss and haemocompatibility of hydroxyapatite ceramics have been studied before and after impregnation of PVA. The nano- hydroxyapatite/PVA composites have superior mechanical properties and reduced wear loss than the non-impregnated porous nano-hydroxyapatite ceramics.

Tribological behavior of Ti6Al4V cellular structures produced by Selective Laser Melting.

PubMed

Bartolomeu, F; Sampaio, M; Carvalho, O; Pinto, E; Alves, N; Gomes, J R; Silva, F S; Miranda, G

2017-05-01

Additive manufacturing (AM) technologies enable the fabrication of innovative structures with complex geometries not easily manufactured by traditional processes. Regarding metallic cellular structures with tailored/customized mechanical and wear performance aiming to biomedical applications, Selective Laser Melting (SLM) is a remarkable solution for their production. Focusing on prosthesis and implants, in addition to a suitable Young's modulus it is important to assess the friction response and wear resistance of these cellular structures in a natural environment. In this sense, five cellular Ti6Al4V structures with different open-cell sizes (100-500µm) were designed and produced by SLM. These structures were tribologicaly tested against alumina using a reciprocating sliding ball-on-plate tribometer. Samples were submerged in Phosphate Buffered Saline (PBS) fluid at 37°C, in order to mimic in some extent the human body environment. The results showed that friction and wear performance of Ti6Al4V cellular structures is influenced by the structure open-cell size. The higher wear resistance was obtained for structures with 100µm designed open-cell size due to the higher apparent area of contact to support tribological loading. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fitting a hand-glove prosthesis to enhance the reconstructed mutilated hand.

PubMed

Leow, M E; Kour, A K; Pereira, B P; Pho, R W

1998-03-01

Microsurgical reconstruction of the severely mutilated hand aimed at improving prehensile functions often does not address the esthetic aspects of the hand. The poor appearance of the reconstructed hand affects its active display and use. A hand-glove prosthesis may be prescribed in this instance to enhance the overall form and function of the mutilated hand. We reviewed 16 cases of mutilating hand injuries in which surgical reconstructions were performed and the patients were subsequently fitted with a hand-glove prosthesis to augment the outcome. An improved appearance was achieved in all patients fitted with the prosthesis. The patients' sense of confidence was also enhanced, which in turn promoted the active and open use of the reconstructed hands. While prescribed primarily to improve the appearance of the reconstructed hands, these prostheses were documented to enhance the physical hand functions in 11 cases by increasing the span of the hand and providing an opposable post and a palmar base for holding and for anchorage. The prosthesis enhanced assistive functions of the reconstructed hands and freed the contralateral normal hand for use in bimanual activities, such as holding a wallet and taking out money, supporting a note pad for writing, and holding a plate at buffet receptions. At the 18-month follow-up visit, 13 (87%) of the patients continued to use their prosthesis. Wear and tear were problems associated with the frequent use of the prosthesis. The expected life span of the prosthesis with daily use ranged from 2 to 3 years. All the patients acknowledged that the prosthesis played a role in their rehabilitation and that it helped them to overcome the initial psychological trauma and to come to terms with their physical loss.

Kinematic analysis of a posterior-stabilized knee prosthesis.

PubMed

Zhao, Zhi-Xin; Wen, Liang; Qu, Tie-Bing; Hou, Li-Li; Xiang, Dong; Bin, Jia

2015-01-20

The goal of total knee arthroplasty (TKA) is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data. Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS) knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0-135° flexion. Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, "rollback" compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis. There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis.

An integrated CAD/CAM/robotic milling method for custom cementless femoral prostheses.

PubMed

Wen-ming, Xi; Ai-min, Wang; Qi, Wu; Chang-hua, Liu; Jian-fei, Zhu; Fang-fang, Xia

2015-09-01

Aseptic loosening is the primary cause of cementless femoral prosthesis failure and is related to the primary stability of the cementless femoral prosthesis in the femoral cavity. The primary stability affects both the osseointegration and the long-term stability of cementless femoral prostheses. A custom cementless femoral prosthesis can improve the fit and fill of the prosthesis in the femoral cavity and decrease the micromotion of the proximal prosthesis such that the primary stability of the custom prosthesis can be improved, and osseointegration of the proximal prosthesis is achieved. These results will help to achieve long-term stability in total hip arthroplasty (THA). In this paper, we introduce an integrated CAD/CAM/robotic method of milling custom cementless femoral prostheses. The 3D reconstruction model uses femoral CT images and 3D design software to design a CAD model of the custom prosthesis. After the transformation matrices between two units of the robotic system are calibrated, consistency between the CAM software and the robotic system can be achieved, and errors in the robotic milling can be limited. According to the CAD model of the custom prosthesis, the positions of the robotic tool points are produced by the CAM software of the CNC machine. The normal vector of the three adjacent robotic tool point positions determines the pose of the robotic tool point. In conclusion, the fit rate of custom pig femur stems in the femoral cavities was 90.84%. After custom femoral prostheses were inserted into the femoral cavities, the maximum gaps between the prostheses and the cavities measured less than 1 mm at the diaphysis and 1.3 mm at the metaphysis. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Survival of various implant-supported prosthesis designs following 36 months of clinical function.

PubMed

Rodriguez, A M; Orenstein, I H; Morris, H F; Ochi, S

2000-12-01

The use of endosseous dental implants to replace natural teeth lost to trauma, dental caries, or periodontal disease has become a predictable form of prosthetic treatment since gaining popularity in the early 1980s. While numerous clinical studies have focused on the survival of implants, few address the survival of different prosthesis designs. Beginning in 1991, 882 prostheses supported by more than 2,900 implants (687 patients) were placed by the Department of Veterans Affairs Dental Implant Clinical Research Group (DICRG). These prostheses were divided into five research strata based on arch location. The recommended design for each stratum was: bar-supported overdenture (maxillary completely edentulous); screw-retained hybrid denture (mandibular completely edentulous); screw-retained fixed partial denture (mandibular and maxillary posterior partially edentulous); and cemented single crown (maxillary anterior single tooth). Alternative overdenture designs were utilized in the edentulous arches when the recommended prosthesis could not be fabricated. Prosthesis success rates for the research strata were calculated for an observation time of up to 36 months following prosthesis placement. Success rates for the maxillary edentulous stratum ranged from 94.6% for the bar-retained overdenture supported by five to six fixtures to 81.8% for the cap-retained overdenture. The mandibular edentulous strata produced success rates of 98.1% for the fixed hybrid prosthesis to 91.7% for the cap-retained prosthesis. Success rates for maxillary and mandibular posterior fixed partial dentures were 94.3% and 92.6%, respectively, while the maxillary anterior single-tooth prosthesis yielded a success rate of 98.1% for the 36-month observation period. The recommended prosthesis designs investigated in this study proved to be reliable, with encouraging success rates for an observation period of 36 months following placement.

Next generation shape memory prosthesis (NiTiBOND) for stapedotomy: Short-term results.

PubMed

Green, J Douglas; McElveen, John T

2017-04-01

To review hearing results and complications for the NiTiBOND next generation shape memory prosthesis and compare them with results for the current shape memory prosthesis (SMart). Retrospective, multicenter chart review. Primary laser stapedotomy was performed using either a NiTiBOND or a SMart prosthesis. Ninety-two ears in 79 patients were included in the study (67.4% female), 52 with the NiTiBOND prosthesis and 40 with the SMart prosthesis. Data collected included demographic variables, pre- and postoperative pure-tone air and bone conduction thresholds, speech discrimination scores, complications, and the need for revision surgery. Pure-tone average (PTA) and PTA air-bone gap (ABG) pre- and postoperative were computed. Success was defined as a postoperative ABG of ≤10 dB. There were no significant differences between groups in hearing results, including improvement in ABG, change in speech discrimination, change in air or bone PTA, or change in high-frequency bone PTA. Short-term (mean = 4.4 and 4.9 weeks, respectively) success rates for the NiTiBOND and SMart prostheses were 84.6% and 70.0%, respectively, with this difference closing at the most recent test (83.7% and 80.0%, respectively). No revision surgery took place in either group, and there were no differences in complications such as dizziness, tinnitus, or taste disturbance, though the NiTiBOND group tended to have a lower rate of transient or permanent vertigo. Compared with the SMart prosthesis, the NiTiBOND prosthesis is a safe prosthesis that achieves at least comparable hearing results and may offer some surgical advantages. 4 Laryngoscope, 127:915-920, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Metabolics of stair ascent with a powered transfemoral prosthesis.

PubMed

Ledoux, E D; Lawson, B E; Shultz, A H; Bartlett, H L; Goldfarb, M

2015-01-01

This paper evaluates the effectiveness of a powered knee and ankle prosthesis for stair ascent through a metabolic assessment comparing energy expenditure of a single transfemoral amputee subject while ascending stairs with the powered prosthesis relative to his passive daily use device, as well as comparing the kinematics and kinetics obtained with the passive prosthesis to healthy biomechanics. The subject wore a portable system that measured pulmonary gaseous exchange rates of oxygen and carbon dioxide while he ascended stairs with each of the prostheses in alternating tests. The results indicated that the amputee's energy expenditure decreased by 32 percent while climbing with the powered prosthesis as compared to his passive one, and the kinematics and kinetics achieved were representative of healthy biomechanics.

Prosthetic Rehabilitation of Mandibular Defects with Fixed-removable Partial Denture Prosthesis Using Precision Attachment: A Twin Case Report.

PubMed

Munot, Vimal Kantilal; Nayakar, Ramesh P; Patil, Raghunath

2017-01-01

The restoration of normal function and esthetic appearance with a dental prosthesis is a major challenge in the rehabilitation of patients who have lost their teeth and surrounding bone because of surgery for oral cyst or tumor. Rehabilitation with fixed or removable prosthesis is even more challenging when the edentulous span is long and the ridge is defective. Anatomic deformities and unfavorable biomechanics encountered in the region of resection add to the misery. In such situation, a fixed-removable prosthesis allows favorable biomechanical stress distribution along with restoration of esthetics, phonetics, comfort, hygiene, and better postoperative care and maintenance. This article describes rehabilitation of two cases with mandibular defects with an attachment-retained fixed-removable hybrid prosthesis.

21 CFR 876.3750 - Testicular prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Testicular prosthesis. 876.3750 Section 876.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Prosthetic Devices § 876.3750 Testicular prosthesis. (a...

Development of Subischial Prosthetic Sockets with Vacuum-Assisted Suspension for Highly Active Persons with Transfemoral Amputations

DTIC Science & Technology

2012-10-01

materials to facilitate dissemination of this technique. 15. SUBJECT TERMS Transfemoral amputation, sub-ischial socket, prosthesis , vacuum-assisted...an appropriate mechanical pump to create suitable vacuum for suspension of the prosthesis ...sockets of highly active prosthesis users

21 CFR 878.3610 - Esophageal prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Esophageal prosthesis. 878.3610 Section 878.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3610 Esophageal prosthesis...

21 CFR 878.3610 - Esophageal prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Esophageal prosthesis. 878.3610 Section 878.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3610 Esophageal prosthesis...

21 CFR 878.3610 - Esophageal prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Esophageal prosthesis. 878.3610 Section 878.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3610 Esophageal prosthesis...

21 CFR 878.3610 - Esophageal prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Esophageal prosthesis. 878.3610 Section 878.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3610 Esophageal prosthesis...

21 CFR 878.3610 - Esophageal prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Esophageal prosthesis. 878.3610 Section 878.3610 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3610 Esophageal prosthesis...

An interim prosthesis program for lower limb amputees: comparison of public and private models of service.

PubMed

Gordon, Robert; Magee, Christopher; Frazer, Anna; Evans, Craig; McCosker, Kathryn

2010-06-01

This study compared the outcomes of an interim mechanical prosthesis program for lower limb amputees operated under a public and private model of service. Over a two-year period, 60 transtibial amputees were fitted with an interim prosthesis as part of their early amputee care. Thirty-four patients received early amputee care under a public model of service, whereby a prosthetist was employed to provide the interim mechanical prosthesis service. The remaining 26 patients received early amputee care under a private model of service, where an external company was contracted to provide the interim mechanical prosthesis service. The results suggested comparable clinical outcomes between the two patient groups. However, the public model appeared to be less expensive with the average labour cost per patient being 29.0% lower compared with the private model. The results suggest that a public model of service may provide a more comprehensive and less expensive interim prosthesis program for lower limb amputees.

A clinical and radiostereometric study of the cemented PFC-sigma prosthesis: a 5-year study of 29 cases with a fixed bearing.

PubMed

von Schewelov, Thord; Besjakov, Jack; Sanzén, Lennart; Carlsson, Ake

2009-07-01

The press-fit condylar (PFC) cruciate-retaining total knee prosthesis is well documented in the literature. In 1997, a modification of the femoral component was introduced, and the prosthesis was renamed PFC-Sigma. The alteration may influence the migratory and rotational pattern of the tibial component and thus long-time survival rate. In this radiostereometric analysis, we found that the micromotion of the PFC-Sigma prosthesis differs slightly from the original PFC design, an advantage of the PFC-Sigma prosthesis. The median maximum total point motion at 5 years was 0.64 mm for the PFC-Sigma design and 0.79 mm for the previous version of PFC (P = .9). However, the PFC-Sigma rotated less around the transverse (x) axis than did the PFC (medians, 0.22 mm and 0.48 mm, respectively; P = .04). From the radiostereometric, radiographic, and clinical data, we conclude that the PFC-Sigma knee prosthesis can be used with confidence.

Gingival Retraction Methods for Fabrication of Fixed Partial Denture: Literature Review

PubMed Central

S, Safari; Ma, Vossoghi Sheshkalani; Mi, Vossoghi Sheshkalani; F, Hoseini Ghavam; M, Hamedi

2016-01-01

Fixed dental prosthesis success requires appropriate impression taking of the prepared finish line. This is critical in either tooth supported fixed prosthesis (crown and bridge) or implant supported fixed prosthesis (solid abutment). If the prepared finish line is adjacent to the gingival sulcus, gingival retraction techniques should be used to decrease the marginal discrepancy among the restoration and the prepared abutment. Accurate marginal positioning of the restoration in the prepared finish line of the abutment is required for therapeutic, preventive and aesthetic purposes. In this article, conventional and modern methods of gingival retraction in the fixed tooth supported prosthesis and fixed implant supported prosthesis are expressed. PubMed and Google Scholar databases were searched manually for studies on gingival tissue managements prior to impression making in fixed dental prosthesis since 1975. Conclusions were extracted and summarized. Keywords were impression making, gingival retraction, cordless retraction, and implant. Gingival retraction techniques can be classified as mechanical, chemical or surgical. In this article, different gingival management techniques are discussed. PMID:28959744

Gingival Retraction Methods for Fabrication of Fixed Partial Denture: Literature Review.

PubMed

S, Safari; Ma, Vossoghi Sheshkalani; Mi, Vossoghi Sheshkalani; F, Hoseini Ghavam; M, Hamedi

2016-06-01

Fixed dental prosthesis success requires appropriate impression taking of the prepared finish line. This is critical in either tooth supported fixed prosthesis (crown and bridge) or implant supported fixed prosthesis (solid abutment). If the prepared finish line is adjacent to the gingival sulcus, gingival retraction techniques should be used to decrease the marginal discrepancy among the restoration and the prepared abutment. Accurate marginal positioning of the restoration in the prepared finish line of the abutment is required for therapeutic, preventive and aesthetic purposes. In this article, conventional and modern methods of gingival retraction in the fixed tooth supported prosthesis and fixed implant supported prosthesis are expressed. PubMed and Google Scholar databases were searched manually for studies on gingival tissue managements prior to impression making in fixed dental prosthesis since 1975. Conclusions were extracted and summarized. Keywords were impression making, gingival retraction, cordless retraction, and implant. Gingival retraction techniques can be classified as mechanical, chemical or surgical. In this article, different gingival management techniques are discussed.

Sensory feedback add-on for upper-limb prostheses.

PubMed

Fallahian, Nader; Saeedi, Hassan; Mokhtarinia, Hamidreza; Tabatabai Ghomshe, Farhad

2017-06-01

Sensory feedback systems have been of great interest in upper-limb prosthetics. Despite tremendous research, there are no commercial modality-matched feedback systems. This article aims to introduce the first detachable and feedback add-on option that can be attached to in-use prostheses. A sensory feedback system was tested on a below-elbow myoelectric prosthesis. The aim was to have the amputee grasp fragile objects without crushing while other accidental feedback sources were blocked. A total of 8 successful trials (out of 10) showed that sensory feedback system decreased the amputee's visual dependency by improving awareness of his prosthesis. Sensory feedback system can be used either as post-fabrication (prosthetic add-on option) or para-fabrication (incorporated into prosthetic design). The use of these direct feedback systems can be explored with a current prosthesis before ordering new high-tech prosthesis. Clinical relevance This technical note introduces the first attach/detach-able sensory feedback system that can simply be added to in-use (myo)electric prosthesis, with no obligation to change prosthesis design or components.

Nontraumatic Fracture of the Femoral Condylar Prosthesis in a Total Knee Arthroplasty Leading to Mechanical Failure

PubMed Central

Swamy, Girish N.; Quah, Conal; Bagouri, Elmunzar; Badhe, Nitin P.

2014-01-01

This paper reports a case of fatigue fracture of the femoral component in a cruciate-retaining cemented total knee arthroplasty (TKA). A 64-year-old man had undergone a primary TKA for osteoarthritis 10 years previously at another institution using the PFC-Sigma prosthesis. The patient recovered fully and was back to his regular activities. He presented with a history of sudden onset pain and locking of the left knee since the preceding three months. There was no history of trauma, and the patient was mobilizing with difficulty using crutches. Radiographs revealed fracture of the posterior condyle of the femoral prosthesis. Revision surgery was performed as an elective procedure revealing the broken prosthesis. The TC3RP-PFC revision prosthesis was used with a medial parapatellar approach. The patient recovered fully without any squeal. Mechanical failure of the knee arthroplasty prosthesis is rare, and nontraumatic fracture of the femoral metallic component has not been reported before. PMID:24587928

Nontraumatic fracture of the femoral condylar prosthesis in a total knee arthroplasty leading to mechanical failure.

PubMed

Swamy, Girish N; Quah, Conal; Bagouri, Elmunzar; Badhe, Nitin P

2014-01-01

This paper reports a case of fatigue fracture of the femoral component in a cruciate-retaining cemented total knee arthroplasty (TKA). A 64-year-old man had undergone a primary TKA for osteoarthritis 10 years previously at another institution using the PFC-Sigma prosthesis. The patient recovered fully and was back to his regular activities. He presented with a history of sudden onset pain and locking of the left knee since the preceding three months. There was no history of trauma, and the patient was mobilizing with difficulty using crutches. Radiographs revealed fracture of the posterior condyle of the femoral prosthesis. Revision surgery was performed as an elective procedure revealing the broken prosthesis. The TC3RP-PFC revision prosthesis was used with a medial parapatellar approach. The patient recovered fully without any squeal. Mechanical failure of the knee arthroplasty prosthesis is rare, and nontraumatic fracture of the femoral metallic component has not been reported before.

Characterization of a new caged proton capable of inducing large pH jumps.

PubMed Central

Barth, Andreas; Corrie, John E T

2002-01-01

A new caged proton, 1-(2-nitrophenyl)ethyl sulfate (caged sulfate), is characterized by infrared spectroscopy and compared with a known caged, proton 2-hydroxyphenyl 1-(2-nitrophenyl)ethyl phosphate (caged HPP). In contrast to caged HPP, caged sulfate can induce large pH jumps and protonate groups that have pK values as low as 2.2. The photolysis mechanism of caged sulfate is analogous to that of P(3)-[1-(2-nitrophenyl)ethyl] ATP (caged ATP), and the photolysis efficiency is similar. The utility of this new caged compound for biological studies was demonstrated by its ability to drive the acid-induced conformational change of metmyoglobin. This transition from the native conformation to a partially unfolded form takes place near pH 4 and was monitored by near-UV absorption spectroscopy. PMID:12414718

The challenge of pelvic discontinuity: cup-cage reconstruction does better than conventional cages in mid-term.

PubMed

Abolghasemian, M; Tangsaraporn, S; Drexler, M; Barbuto, R; Backstein, D; Safir, O; Kuzyk, P; Gross, A

2014-02-01

The use of ilioischial cage reconstruction for pelvic discontinuity has been replaced by the Trabecular Metal (Zimmer, Warsaw, Indiana) cup-cage technique in our institution, due to the unsatisfactory outcome of using a cage alone in this situation. We report the outcome of 26 pelvic discontinuities in 24 patients (20 women and four men, mean age 65 years (44 to 84)) treated by the cup-cage technique at a mean follow-up of 82 months (12 to 113) and compared them with a series of 19 pelvic discontinuities in 19 patients (18 women and one man, mean age 70 years (42 to 86)) treated with a cage at a mean follow-up of 69 months (1 to 170). The clinical and radiological outcomes as well as the survivorship of the groups were compared. In all, four of the cup-cage group (15%) and 13 (68%) of the cage group failed due to septic or aseptic loosening. The seven-year survivorship was 87.2% (95% confidence interval (CI) 71 to 103) for the cup-cage group and 49.9% (95% CI 15 to 84) for the cage-alone group (p = 0.009). There were four major complications in the cup-cage group and nine in the cage group. Radiological union of the discontinuity was found in all successful cases in the cup-cage group and three of the successful cage cases. Three hips in the cup-cage group developed early radiological migration of the components, which stabilised with a successful outcome. Cup-cage reconstruction is a reliable technique for treating pelvic discontinuity in mid-term follow-up and is preferred to ilioischial cage reconstruction. If the continuity of the bone graft at the discontinuity site is not disrupted, early migration of the components does not necessarily result in failure.

Laryngeal complications after type 1 thyroplasty.

PubMed

Cotter, C S; Avidano, M A; Crary, M A; Cassisi, N J; Gorham, M M

1995-12-01

Type I thyroplasty has become a primary surgical choice for voice restoration in patients with glottal incompetence. This study examines factors associated with laryngeal complications after type I thyroplasty. Ten laryngoscopic variables were analyzed from preoperative, intraoperative, and postoperative videolaryngoscopies of 51 patients undergoing 58 medialization procedures. Ten patient and operative variables were examined by medical record review. Major complications were defined as wound hemorrhage, airway obstruction, or prosthesis extrusion. Minor complications were defined as vocal fold hematoma without airway obstruction or prosthesis movement. The major complication rate was 8.6%, and the minor complication rate was 29%. No delayed hemorrhage or airway obstruction occurred. Prosthesis extrusion occurred in five (8.6%) patients 1 week to 5 months after surgery. Extrusion was associated with suboptimal prosthesis placement in 80% of cases. Two patients retained excellent glottal closure despite extrusion. Vocal fold hematoma was identified in 14 (24%) cases and resolved within 1 week. Prosthesis movement occurred in three (5%) patients 1 week to 6 months after surgery and resulted in poor glottal closure. All patients with prosthesis extrusion or movement were female. Type I thyroplasty remains a safe outpatient procedure with few major complications. Prosthesis extrusion was associated with suboptimal prosthesis placement and may or may not result in poor glottal closure. Minor vocal fold hematomas were relatively frequent, resolved rapidly, and were not associated with airway obstruction. Female patients may be more prone to complications because of their small laryngeal size.

Implications of prosthesis funding structures on the use of prostheses: experiences of individuals with upper limb absence.

PubMed

Biddiss, Elaine; McKeever, Patricia; Lindsay, Sally; Chau, Tom

2011-06-01

While sparsely researched, funding structures may play an important role in use of and satisfaction with prostheses and related health services. The objectives of this study were to (1) quantify the direct costs of prosthesis wear, (2) explore variations in funding distribution, and (3) describe the role of affordability in prosthesis selection and wear. An anonymous, online cross-sectional descriptive survey was administered. Analyses were conducted of qualitative and quantitative data extracted from an international sample of 242 individuals with upper limb absence. Access to prosthesis funding was variable and fluctuated with age, level of limb absence and country of care. Of individuals who gave details on prosthetic costs, 63% (n = 69) were fully reimbursed for their prosthetic expenses, while 37% (n = 40) were financially disadvantaged by the cost of components (mean [SD] US$9,574 [$9,986]) and their ongoing maintenance (US$1,936 [$3,179]). Of the 71 non-wearers in this study, 48% considered cost an influential factor in their decision not to adopt prosthesis use. Prosthesis funding is neither homogeneous nor transparent and can be influential in both the selection and use of a prosthetic device. Inequitable access to prosthesis funding is evident in industrialized nations and may lead to prosthesis abandonment and/or diminished quality of life for individuals with upper limb absences. Increased efforts are required to ensure equitable access to upper limb prosthetics and related services in line with individuals' needs.

Mobile-bearing TKA improved the anteroposterior joint stability in mid-flexion range comparing to fixed-bearing TKA.

PubMed

Minoda, Yukihide; Ikebuchi, Mitsuhiko; Mizokawa, Shigekazu; Ohta, Yoichi; Nakamura, Hiroaki

2016-11-01

Proper anteroposterior (AP) joint displacement is an important indicator of good clinical outcome following total knee arthroplasty (TKA). We hypothesized that a newly introduced mobile-bearing posterior stabilized (PS) prosthesis reduces the AP joint displacement. The aim of this study is to compare the AP joint displacement between a newly introduced mobile-bearing PS TKA in one knee and a conventional fixed-bearing PS TKA in other knee. 82 knees in 41 patients who had bilateral TKAs were investigated. All the patients received a conventional fixed-bearing PS prosthesis in one knee and a highly congruent mobile-bearing PS prosthesis in the other knee. AP joint displacement was measured using the KT-2000 arthrometer, at 30° and 75° in flexion, at average of 3.3 years after the operation. AP joint displacements at 30° in flexion were 6 ± 3 mm in the knees with the mobile-bearing PS prosthesis and 9 ± 4 mm in the knee with fixed-bearing PS prosthesis (p < 0.001). AP joint displacements at 75° in flexion were 4 ± 2 mm in the knees with the mobile-bearing PS prosthesis and 6 ± 3 mm in the knee with fixed-bearing PS prosthesis (p < 0.001). This study suggested that the design of the prosthesis can improve the AP joint stability in mid-flexion range.

Reproductive Performance of Mice in Disposable and Standard Individually Ventilated Cages

PubMed Central

Ferguson, Danielle R; Bailey, Michele M

2013-01-01

This study assessed the reproductive performance of mice housed in 2 types of individually ventilated caging systems. Breeding pairs from 48 female and 24 male mice of 3 established transgenic mouse breeding colonies were placed in either a standard or disposable ventilated caging system. For 3 breeding cycles, the number of pups born, pup survival rate to weaning, time interval between litters, and pup weights were monitored for each breeding pair. Disposable and standard cages were maintained in the same location during breeding. Environmental parameters included intracage temperature, humidity, and ammonia and carbon dioxide levels and room light intensity and sound. Overall, 776 offspring were produced. Breeding performance did not differ significantly between the 2 cage types. By 11 wk of age, the weights of pups from both cage types were equivalent. The intracage temperature was 1.1 °F warmer and light intensity at the site of the nest was 34 lx dimmer in disposable cages than in standard caging. The difference in lighting likely was due to nest location; the nests in the disposable cages were at the back of the cages and away from the anterior air supply, whereas in standard caging, nests were at the front of the cages, with the air supply at the rear. Under these husbandry conditions, mice housed in disposable caging systems have comparable breeding performance to those housed in standard individually ventilated cages. PMID:23849403

Neutron and X-ray powder diffraction study of skutterudite thermoelectrics

DOE PAGES

Wang, H.; Kirkham, M. J.; Watkins, T. R.; ...

2016-02-17

N- and p-type filled-skutterudite materials prepared for thermoelectric power generation modules were analyzed by neutron diffraction at the POWGEN beam line of the Spallation Neutron Source (SNS) and X-ray diffraction (XRD). The skutterudite powders were processed by melt spinning, followed by ball milling and annealing. The n-type material consists of Ba–Yb–Co–Sb and the p-type material consists of Di–Fe–Ni–Sb or Di–Fe–Co–Sb (Di = didymium, an alloy of Pr and Nd). Powders for prototype module fabrication from General Motors and Marlow Industries were analyzed in this study. XRD and neutron diffraction studies confirm that both the n- and p-type materials have cubicmore » symmetry. Structural Rietveld refinements determined the lattice parameters and atomic parameters of the framework and filler atoms. The cage filling fraction was found to depend linearly on the lattice parameter, which in turn depends on the average framework atom size. Ultimately, this knowledge may allow the filling fraction of these skutterudite materials to be purposefully adjusted, thereby tuning the thermoelectric properties.« less

21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Finger joint metal/polymer constrained cemented... metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint metal/polymer..., 1996 for any finger joint metal/polymer constrained cemented prosthesis that was in commercial...

21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Finger joint metal/polymer constrained cemented... metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint metal/polymer..., 1996 for any finger joint metal/polymer constrained cemented prosthesis that was in commercial...

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Passive tendon prosthesis. 888.3025 Section 888.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a...

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Passive tendon prosthesis. 888.3025 Section 888.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a...

21 CFR 888.3025 - Passive tendon prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Passive tendon prosthesis. 888.3025 Section 888.3025 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3025 Passive tendon prosthesis. (a...

21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Finger joint metal/polymer constrained cemented... metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint metal/polymer..., 1996 for any finger joint metal/polymer constrained cemented prosthesis that was in commercial...

21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Finger joint metal/polymer constrained cemented... metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint metal/polymer..., 1996 for any finger joint metal/polymer constrained cemented prosthesis that was in commercial...

21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Finger joint metal/polymer constrained cemented... metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint metal/polymer..., 1996 for any finger joint metal/polymer constrained cemented prosthesis that was in commercial...

21 CFR 872.3960 - Mandibular condyle prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Mandibular condyle prosthesis. 872.3960 Section 872.3960 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3960 Mandibular condyle prosthesis. (a...

21 CFR 872.3950 - Glenoid fossa prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Glenoid fossa prosthesis. 872.3950 Section 872.3950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3950 Glenoid fossa prosthesis. (a) Identification...

21 CFR 878.3680 - Nose prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nose prosthesis. 878.3680 Section 878.3680 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3680 Nose prosthesis. (a...

21 CFR 878.3550 - Chin prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Chin prosthesis. 878.3550 Section 878.3550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3550 Chin prosthesis. (a...

21 CFR 878.3720 - Tracheal prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Tracheal prosthesis. 878.3720 Section 878.3720 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3720 Tracheal prosthesis. (a...

21 CFR 878.3750 - External prosthesis adhesive.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false External prosthesis adhesive. 878.3750 Section 878.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3750 External prosthesis...

21 CFR 878.3750 - External prosthesis adhesive.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false External prosthesis adhesive. 878.3750 Section 878.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3750 External prosthesis...

21 CFR 878.3550 - Chin prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Chin prosthesis. 878.3550 Section 878.3550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3550 Chin prosthesis. (a...

21 CFR 878.3750 - External prosthesis adhesive.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false External prosthesis adhesive. 878.3750 Section 878.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3750 External prosthesis...

21 CFR 878.3550 - Chin prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Chin prosthesis. 878.3550 Section 878.3550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3550 Chin prosthesis. (a...

21 CFR 878.3550 - Chin prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Chin prosthesis. 878.3550 Section 878.3550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3550 Chin prosthesis. (a...

21 CFR 878.3550 - Chin prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Chin prosthesis. 878.3550 Section 878.3550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3550 Chin prosthesis. (a...

21 CFR 878.3680 - Nose prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nose prosthesis. 878.3680 Section 878.3680 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3680 Nose prosthesis. (a...

21 CFR 878.3750 - External prosthesis adhesive.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false External prosthesis adhesive. 878.3750 Section 878.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3750 External prosthesis...

21 CFR 878.3680 - Nose prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nose prosthesis. 878.3680 Section 878.3680 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3680 Nose prosthesis. (a...

21 CFR 878.3680 - Nose prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nose prosthesis. 878.3680 Section 878.3680 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3680 Nose prosthesis. (a...

21 CFR 878.3680 - Nose prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nose prosthesis. 878.3680 Section 878.3680 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3680 Nose prosthesis. (a...

21 CFR 878.3750 - External prosthesis adhesive.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false External prosthesis adhesive. 878.3750 Section 878.3750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3750 External prosthesis...

Effects of wind speed on aerosol spray penetration in adult mosquito bioassay cages.

PubMed

Hoffmann, W Clint; Fritz, Bradley K; Farooq, Muhammad; Cooperband, Miriam F

2008-09-01

Bioassay cages are commonly used to assess efficacy of insecticides against adult mosquitoes in the field. To correlate adult mortality readings to insecticidal efficacy and/or spray application parameters properly, it is important to know how the cage used in the bioassay interacts with the spray cloud containing the applied insecticide. This study compared the size of droplets, wind speed, and amount of spray material penetrating cages and outside of cages in a wind tunnel at different wind speeds. Two bioassay cages, Center for Medical, Agricultural and Veterinary Entomology (CMAVE) and Circle, were evaluated. The screen materials used on these cages reduced the size of droplets, wind speed, and amount of spray material inside the cages as compared to the spray cloud and wind velocity outside of the cages. When the wind speed in the dispersion tunnel was set at 0.6 m/sec (1.3 mph), the mean wind speed inside of the CMAVE Bioassay Cage and Circle Cage was 0.045 m/sec (0.10 mph) and 0.075 m/sec (0.17 mph), respectively. At air velocities of 2.2 m/sec (4.9 mph) in the dispersion tunnel, the mean wind speed inside of the CMAVE Bioassay Cage and Circle Cage was 0.83 m/sec (1.86 mph) and 0.71 m/sec (1.59 mph), respectively. Consequently, there was a consistent 50-70% reduction of spray material penetrating the cages compared to the spray cloud that approached the cages. These results provide a better understanding of the impact of wind speed, cage design, and construction on ultra-low-volume spray droplets.

Long-term effects of placing one or two cages in instrumented posterior lumbar interbody fusion.

PubMed

Zhang, Mingzheng; Pu, Fang; Xu, Liqiang; Zhang, Linlin; Yao, Jie; Li, Deyu; Wang, Yu; Fan, Yubo

2016-06-01

Posterior lumbar interbody fusion (PLIF) is an established surgical procedure for spine stabilization after the removal of an intervertebral disc. Researches have shown that inserting a single oblique cage has a similar immediate effect to coupled cages, and it has been proposed that single-cage PLIF is a useful alternative to traditional two-cage PLIF. However, it is not clear whether placing one or two cages represents the best choice for long-term fusion. The aim of this study is to examine how cage placement affects bone remodeling after PLIF surgery, and how this consequently impacts the long-term fusion process. A finite element model of a L3-L4 lumbar spine with PLIF was developed. The spinal segment was modeled with a partial laminectomy and a discectomy with partial facetectomy, and implanted with posterior pedicle screws. Two models were analyzed, one with coupled parallel cages and one with a single oblique cage. Adaptive bone remodeling was simulated according to Huiskes' criterion. The results showed that in the initial state prior to any bone remodeling, cage stress, cage subsidence and cage dislodgement in the single cage model were all greater than in the coupled cage model. In the final state after significant bone remodeling had taken place, these parameters had decreased in both models and the differences between the two models were reduced. Also, the single cage model demonstrated superior bone development in the bone graft when placed under a constant 400 N axial compressive load. Based on the long-term results, instrumented PLIF with a single cage could also be encouraged in clinical practice.

Ball Screw Actuator Including a Stop with an Integral Guide

NASA Technical Reports Server (NTRS)

Wingett, Paul T. (Inventor); Perek, John (Inventor); Geck, Kellan (Inventor)

2015-01-01

An actuator includes a housing assembly, a ball nut, a ball screw, and a ball screw stop. The ball nut is rotationally mounted in the housing assembly, is adapted to receive an input torque, and is configured, upon receipt thereof, to rotate and supply a drive force. The ball screw is mounted within the housing assembly and extends through the ball nut. The ball screw has a first end and a second end, and is coupled to receive the drive force from the ball nut. The ball screw is configured, upon receipt of the drive force, to selectively translate between a stow position and a deploy position. The ball screw stop is mounted on the ball screw to translate therewith and is configured to at selectively engage the housing assembly while the ball screw is translating, and engage the ball nut when the ball screw is in the deploy position.

A novel test cage with an air ventilation system as an alternative to conventional cages for the efficacy testing of mosquito repellents.

PubMed

Obermayr, U; Rose, A; Geier, M

2010-11-01

We have developed a novel test cage and improved method for the evaluation of mosquito repellents. The method is compatible with the United States Environmental Protection Agency, 2000 draft OPPTS 810.3700 Product Performance Test Guidelines for Testing of Insect Repellents. The Biogents cages (BG-cages) require fewer test mosquitoes than conventional cages and are more comfortable for the human volunteers. The novel cage allows a section of treated forearm from a volunteer to be exposed to mosquito probing through a window. This design minimizes residual contamination of cage surfaces with repellent. In addition, an air ventilation system supplies conditioned air to the cages after each single test, to flush out and prevent any accumulation of test substances. During biting activity tests, the untreated skin surface does not receive bites because of a screen placed 150 mm above the skin. Compared with the OPPTS 810.3700 method, the BG-cage is smaller (27 liters, compared with 56 liters) and contains 30 rather than hundreds of blood-hungry female mosquitoes. We compared the performance of a proprietary repellent formulation containing 20% KBR3023 with four volunteers on Aedes aegypti (L.) (Diptera: Culicidae) in BG- and conventional cages. Repellent protection time was shorter in tests conducted with conventional cages. The average 95% protection time was 4.5 +/- 0.4 h in conventional cages and 7.5 +/- 0.6 h in the novel BG-cages. The protection times measured in BG-cages were more similar to the protection times determined with these repellents in field tests.

Influence of 5 Different Caging Types and the Use of Cage-Changing Stations on Mouse Allergen Exposure

PubMed Central

Feistenauer, Susan; Sander, Ingrid; Schmidt, Jörg; Zahradnik, Eva; Raulf, Monika; Brielmeier, Markus

2014-01-01

Animal allergens constitute a serious health risk in laboratory animal facilities. To assess possibilities for allergen reduction by technical and organizational measures, we studied personnel exposure to mouse urinary aeroallergens in an animal facility with a holding capacity of 30,000 cages. Short-term (2 h) and intermediate-term (12 h) stationary samples (n = 107) and short-term (2 h) personnel samples (n = 119) were collected on polytetrafluorethylene filters by using air pumps. Long-term (14 d) stationary dust samples containing airborne allergens (n = 165) were collected with electrostatic dust fall collectors (EDC). Mouse allergens were quantified by ELISA. Personnel samples were collected during bedding disposal and refilling of clean cages as well as during cage changing with and without use of cage-changing station. Animal rooms were equipped with either open cages, cages with a soft filter top, cages with a rigid filter top (static microisolation caging), or with individually ventilated cages (IVC) with either a sealed or nonsealed lid, each in positive- or negative-pressure mode. Highest personnel allergen exposure was detected during cage change and emptying of soiled cages. Allergen concentrations were lowest in rooms with sealed IVC under positive or negative pressure, with unsealed IVC under negative pressure, and with static microisolation caging. The use of cage-changing stations and a vacuum bedding-disposal system reduced median personnel exposures 14- to 25-fold, respectively. Using sealed IVC and changing stations minimized allergen exposure, indicating that state-of-the-art equipment reduces exposure to mouse allergens and decreases health risks among animal facility personnel. PMID:25199090

21 CFR 888.3210 - Finger joint metal/metal constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Finger joint metal/metal constrained cemented... metal/metal constrained cemented prosthesis. (a) Identification. A finger joint metal/metal constrained..., 1996 for any finger joint metal/metal constrained cemented prosthesis that was in commercial...

21 CFR 888.3210 - Finger joint metal/metal constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Finger joint metal/metal constrained cemented... metal/metal constrained cemented prosthesis. (a) Identification. A finger joint metal/metal constrained..., 1996 for any finger joint metal/metal constrained cemented prosthesis that was in commercial...

21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Finger joint metal/metal constrained uncemented... metal/metal constrained uncemented prosthesis. (a) Identification. A finger joint metal/metal... Administration on or before December 26, 1996 for any finger joint metal/metal constrained uncemented prosthesis...

21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Finger joint metal/metal constrained uncemented... metal/metal constrained uncemented prosthesis. (a) Identification. A finger joint metal/metal... Administration on or before December 26, 1996 for any finger joint metal/metal constrained uncemented prosthesis...

21 CFR 888.3100 - Ankle joint metal/composite semi-constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ankle joint metal/composite semi-constrained... Ankle joint metal/composite semi-constrained cemented prosthesis. (a) Identification. An ankle joint metal/composite semi-constrained cemented prosthesis is a device intended to be implanted to replace an...

21 CFR 888.3490 - Knee joint femorotibial metal/composite non-constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femorotibial metal/composite non... § 888.3490 Knee joint femorotibial metal/composite non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite non-constrained cemented prosthesis is a device...

21 CFR 888.3500 - Knee joint femorotibial metal/composite semi-constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femorotibial metal/composite semi... § 888.3500 Knee joint femorotibial metal/composite semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite semi-constrained cemented prosthesis is a two-part...

21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint patellofemorotibial polymer/metal/metal... § 888.3550 Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis is a device...

Facial recognition using enhanced pixelized image for simulated visual prosthesis.

PubMed

Li, Ruonan; Zhhang, Xudong; Zhang, Hui; Hu, Guanshu

2005-01-01

A simulated face recognition experiment using enhanced pixelized images is designed and performed for the artificial visual prosthesis. The results of the simulation reveal new characteristics of visual performance in an enhanced pixelization condition, and then new suggestions on the future design of visual prosthesis are provided.

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/polymer constrained... Knee joint femorotibial metal/polymer constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer constrained cemented prosthesis is a device intended to be implanted to replace part...

21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a device...

21 CFR 888.3530 - Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/polymer semi... § 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device intended...

21 CFR 888.3660 - Shoulder joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/polymer semi-constrained... Shoulder joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A shoulder joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a...

21 CFR 888.3540 - Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemoral polymer/metal semi... § 888.3540 Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis. (a) Identification. A knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis is a two-part...

21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemorotibial polymer/metal/metal... § 888.3550 Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis is a device...

21 CFR 888.3650 - Shoulder joint metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/polymer non-constrained... Shoulder joint metal/polymer non-constrained cemented prosthesis. (a) Identification. A shoulder joint metal/polymer non-constrained cemented prosthesis is a device intended to be implanted to replace a...

21 CFR 888.3530 - Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femorotibial metal/polymer semi... § 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device intended...

21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Shoulder joint glenoid (hemi-shoulder) metallic... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket) component...

21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Shoulder joint humeral (hemi-shoulder) metallic... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as cobalt-chromium...

21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Shoulder joint glenoid (hemi-shoulder) metallic... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket) component...

21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Shoulder joint humeral (hemi-shoulder) metallic... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as cobalt-chromium...

21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Shoulder joint glenoid (hemi-shoulder) metallic... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket) component...

21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint glenoid (hemi-shoulder) metallic... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket) component...

21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint humeral (hemi-shoulder) metallic... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as cobalt-chromium...

21 CFR 888.3680 - Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Shoulder joint glenoid (hemi-shoulder) metallic... Shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis. (a) Identification. A shoulder joint glenoid (hemi-shoulder) metallic cemented prosthesis is a device that has a glenoid (socket) component...

21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Shoulder joint humeral (hemi-shoulder) metallic... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as cobalt-chromium...

21 CFR 888.3690 - Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Shoulder joint humeral (hemi-shoulder) metallic... Shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis. (a) Identification. A shoulder joint humeral (hemi-shoulder) metallic uncemented prosthesis is a device made of alloys, such as cobalt-chromium...

21 CFR 888.3500 - Knee joint femorotibial metal/composite semi-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/composite semi... § 888.3500 Knee joint femorotibial metal/composite semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite semi-constrained cemented prosthesis is a two-part...

21 CFR 888.3100 - Ankle joint metal/composite semi-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ankle joint metal/composite semi-constrained... Ankle joint metal/composite semi-constrained cemented prosthesis. (a) Identification. An ankle joint metal/composite semi-constrained cemented prosthesis is a device intended to be implanted to replace an...

21 CFR 888.3490 - Knee joint femorotibial metal/composite non-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/composite non... § 888.3490 Knee joint femorotibial metal/composite non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/composite non-constrained cemented prosthesis is a device...

21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a device...

21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a device...

21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellofemorotibial polymer/metal/metal... § 888.3550 Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis is a device...

21 CFR 888.3530 - Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femorotibial metal/polymer semi... § 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device intended...

21 CFR 888.3530 - Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femorotibial metal/polymer semi... § 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device intended...

21 CFR 888.3530 - Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femorotibial metal/polymer semi... § 888.3530 Knee joint femorotibial metal/polymer semi-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device intended...

21 CFR 888.3565 - Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellofemorotibial metal/polymer... Devices § 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis. (a) Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a device...

21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellofemorotibial polymer/metal/metal... § 888.3550 Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis is a device...

21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellofemorotibial polymer/metal/metal... § 888.3550 Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis is a device...

Development of Sub-Ischial Prosthetic Sockets with Vacuum-Assisted Suspension for Highly Active Persons with Transfemoral Amputations

DTIC Science & Technology

2013-10-01

15. SUBJECT TERMS Transfemoral amputation, sub-ischial socket, prosthesis , vacuum-assisted suspension 16. SECURITY CLASSIFICATION OF: 17...vacuum for suspension of the prosthesis ...14 Task 6 Determine range of volumes to be evacuated from transfemoral sockets of highly active prosthesis users

21 CFR 878.3590 - Ear prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ear prosthesis. 878.3590 Section 878.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3590 Ear prosthesis. (a) Identification. An...

21 CFR 878.3590 - Ear prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ear prosthesis. 878.3590 Section 878.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3590 Ear prosthesis. (a) Identification. An...

21 CFR 878.3590 - Ear prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ear prosthesis. 878.3590 Section 878.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3590 Ear prosthesis. (a) Identification. An...

21 CFR 878.3590 - Ear prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ear prosthesis. 878.3590 Section 878.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3590 Ear prosthesis. (a) Identification. An...

21 CFR 878.3590 - Ear prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ear prosthesis. 878.3590 Section 878.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3590 Ear prosthesis. (a) Identification. An...

21 CFR 888.6 - Degree of constraint.

Code of Federal Regulations, 2010 CFR

2010-04-01

... replacement and prevents dislocation of the prosthesis in more than one anatomic plane and consists of either... translation and rotation of the prosthesis in one or more planes via the geometry of its articulating surfaces... total joint replacement and restricts minimally prosthesis movement in one or more planes. Its...

Prosthetic Rehabilitation of Mandibular Defects with Fixed-removable Partial Denture Prosthesis Using Precision Attachment: A Twin Case Report

PubMed Central

Munot, Vimal Kantilal; Nayakar, Ramesh P.; Patil, Raghunath

2017-01-01

The restoration of normal function and esthetic appearance with a dental prosthesis is a major challenge in the rehabilitation of patients who have lost their teeth and surrounding bone because of surgery for oral cyst or tumor. Rehabilitation with fixed or removable prosthesis is even more challenging when the edentulous span is long and the ridge is defective. Anatomic deformities and unfavorable biomechanics encountered in the region of resection add to the misery. In such situation, a fixed-removable prosthesis allows favorable biomechanical stress distribution along with restoration of esthetics, phonetics, comfort, hygiene, and better postoperative care and maintenance. This article describes rehabilitation of two cases with mandibular defects with an attachment-retained fixed-removable hybrid prosthesis. PMID:29042738

Design of a power-asymmetric actuator for a transtibial prosthesis.

PubMed

Bartlett, Harrison L; Lawson, Brian E; Goldfarb, Michael

2017-07-01

This paper presents the design and characterization of a power-asymmetric actuator for a transtibial prosthesis. The device is designed to provide the combination of: 1) joint locking, 2) high power dissipation, and 3) low power generation. This actuator functionality allows for a prosthesis to be designed with minimal mass and power consumption relative to a fully-powered robotic prosthesis while maintaining much of the functionality necessary for activities of daily living. The actuator achieves these design characteristics while maintaining a small form factor by leveraging a combination of electromechanical and hydraulic components. The design of the actuator is described herein, and results of an experimental characterization are provided that indicate that the actuator is capable of providing the functional capabilities required of an ankle prosthesis in a compact and lightweight package.

Consumer design priorities for upper limb prosthetics.

PubMed

Biddiss, Elaine; Beaton, Dorcas; Chau, Tom

2007-11-01

To measure consumer satisfaction with upper limb prosthetics and provide an enumerated list of design priorities for future developments. A self-administered, anonymous survey collected information on participant demographics, history of and goals for prosthesis use, satisfaction, and design priorities. The questionnaire was available online and in paper format and was distributed through healthcare providers, community support groups, and one prosthesis manufacturer; 242 participants of all ages and levels of upper limb absence completed the survey. Rates of rejection for myoelectric hands, passive hands, and body-powered hooks were 39%, 53%, and 50%, respectively. Prosthesis wearers were generally satisfied with their devices while prosthesis rejecters were dissatisfied. Reduced prosthesis weight emerged as the highest priority design concern of consumers. Lower cost ranked within the top five design priorities for adult wearers of all device types. Life-like appearance is a priority for passive/cosmetic prostheses, while improved harness comfort, wrist movement, grip control and strength are required for body-powered devices. Glove durability, lack of sensory feedback, and poor dexterity were also identified as design priorities for electric devices. Design priorities reflect consumer goals for prosthesis use and vary depending on the type of prosthesis used and age. Future design efforts should focus on the development of more light-weight, comfortable prostheses.

Rehabilitation of a missing ear with an implant retained auricular prosthesis

PubMed Central

Guttal, Satyabodh Sheshraj; Shanbhag, Shruti; Kulkarni, Sudhindra S.; Thakur, Srinath L.

2015-01-01

Burns can leave a patient with a severely debilitating disability even after treatment. The objectives of burn rehabilitation are to minimize the adverse effects caused by the injury while rehabilitating the patient's physical and psychological well-being, maximizing social integration. Long-term success of maxillofacial prostheses mainly depends on the retention. Extra oral implant retained prostheses have proved to be a predictable treatment option for maxillofacial rehabilitation. Replacement of a severely deformed external ear with burned tissues may be satisfactorily accomplished by a cosmetic prosthesis anchored by implants integrated in the skull. The use of such implants is now a well-recognized method for creating a stable result in maxillofacial rehabilitation. This case report describes a safe, simple and economical method for the rehabilitation of a patient with missing right auricle using an implant supported silicone prosthesis. The implant was placed in the mastoid region of the temporal bone. Reconstruction of the ear was done with auricular silicone prosthesis, retained using magnets incorporated in an autopolymerizing resin shim to decrease the weight of the prosthesis on a single implant. This method eliminates the need of tedious laboratory procedures and exact casting and fitting requirements of a metal substructure while minimizing the overall weight and cost of the prosthesis while maintaining adequate support, esthetics and retention of the prosthesis. PMID:26929490

Tracheal replacement in rabbits with a new composite silicone-metallic prosthesis.

PubMed

Dodge-Khatami, Ali; Niessen, Hans W M; Koole, Leo H; Klein, Marloes G; van Gulik, Thomas M; de Mol, Bas A J M

2003-09-01

A new composite silicone-metallic prosthesis was tested, studying the potential for respiratory epithelial covering over the biocompatible inner lining, in a rabbit survival model. Seven New Zealand White rabbits underwent near-total excision of their trachea and implantation of a sterile prosthesis. After 2 months, they were sacrificed and the prostheses were retrieved. Specimens were fixed and histologically examined for tissue reaction around the prosthesis, at the anastomotic lines, and particularly for the presence or absence of epithelialization of the inner lumen over the biocompatible surface. All rabbits survived the operation. At 2 months, the outer layer of the prosthesis was consistently covered with fibrosis and neutrophils. The inner layer showed necrotic cells and scant re-epithelialization over the biocompatible lining, up to 5 mm beyond the anastomosis, with no evidence of organized respiratory epithelium in the middle sections. The new prosthesis is a viable temporary solution for airway replacement in rabbits. Granulation tissue was not observed at the anastomosis, and re-epithelialization did occur, but failed to achieve full-length luminal covering. The potential for granulation tissue does not yet make this an ideal long-term solution. Improvements in prosthesis design or biocompatibility are required, and need to be re-evaluated before applicability for chronic use.

Design and Characterization of a Quasi-Passive Pneumatic Foot-Ankle Prosthesis.

PubMed

Lee, Jeffrey D; Mooney, Luke M; Rouse, Elliott J

2017-07-01

The majority of commercially available passive prosthetic feet are not capable of providing joint mechanics that match that of the intact human ankle. Due to their cantilever design, their stiffness characteristics contrast with what has been observed in the biological ankle, namely, an increase in stiffness during the stance phase of walking. In this paper, we introduce the design and control of a pneumatic foot-ankle prosthesis that attempts to provide biomimetic mechanics. The prosthesis is comprised of a pneumatic cylinder in series with a fiberglass leaf spring, and a solenoid valve to control the flow of air between the two sides of the cylinder. The solenoid valve acts as a mechanical clutch, enabling resetting of the ankle's equilibrium position. By adjusting the pressure inside the cylinder, the prosthesis can be customized to provide a range of ankle mechanics. A mechanical testing machine is used to compare the torque-angle curve of the pneumatic prosthesis with a low-profile passive prosthetic foot. Finally, data are presented of one transtibial amputee walking with the prosthesis at 1.2 m/s. The testing shows that the pneumatic prosthesis is capable of providing an appropriate range of motion as well a maximum torque of 94 Nm, while returning approximately 11.5 J of energy.

Developing an Ear Prosthesis Fabricated in Polyvinylidene Fluoride by a 3D Printer with Sensory Intrinsic Properties of Pressure and Temperature

PubMed Central

Suaste-Gómez, Ernesto; Rodríguez-Roldán, Grissel; Reyes-Cruz, Héctor; Terán-Jiménez, Omar

2016-01-01

An ear prosthesis was designed in 3D computer graphics software and fabricated using a 3D printing process of polyvinylidene fluoride (PVDF) for use as a hearing aid. In addition, the prosthesis response to pressure and temperature was observed. Pyroelectric and piezoelectric properties of this ear prosthesis were investigated using an astable multivibrator circuit, as changes in PVDF permittivity were observed according to variations of pressure and temperature. The results show that this prosthesis is reliable for use under different conditions of pressure (0 Pa to 16,350 Pa) and temperature (2 °C to 90 °C). The experimental results show an almost linear and inversely proportional behavior between the stimuli of pressure and temperature with the frequency response. This 3D-printed ear prosthesis is a promising tool and has a great potentiality in the biomedical engineering field because of its ability to generate an electrical potential proportional to pressure and temperature, and it is the first time that such a device has been processed by the additive manufacturing process (3D printing). More work needs to be carried out to improve the performance, such as electrical stimulation of the nervous system, thereby extending the purpose of a prosthesis to the area of sensory perception. PMID:26959026

Developing an Ear Prosthesis Fabricated in Polyvinylidene Fluoride by a 3D Printer with Sensory Intrinsic Properties of Pressure and Temperature.

PubMed

Suaste-Gómez, Ernesto; Rodríguez-Roldán, Grissel; Reyes-Cruz, Héctor; Terán-Jiménez, Omar

2016-03-04

An ear prosthesis was designed in 3D computer graphics software and fabricated using a 3D printing process of polyvinylidene fluoride (PVDF) for use as a hearing aid. In addition, the prosthesis response to pressure and temperature was observed. Pyroelectric and piezoelectric properties of this ear prosthesis were investigated using an astable multivibrator circuit, as changes in PVDF permittivity were observed according to variations of pressure and temperature. The results show that this prosthesis is reliable for use under different conditions of pressure (0 Pa to 16,350 Pa) and temperature (2 °C to 90 °C). The experimental results show an almost linear and inversely proportional behavior between the stimuli of pressure and temperature with the frequency response. This 3D-printed ear prosthesis is a promising tool and has a great potentiality in the biomedical engineering field because of its ability to generate an electrical potential proportional to pressure and temperature, and it is the first time that such a device has been processed by the additive manufacturing process (3D printing). More work needs to be carried out to improve the performance, such as electrical stimulation of the nervous system, thereby extending the purpose of a prosthesis to the area of sensory perception.

Interdisciplinary interface between fixed prosthodontics and periodontics.

PubMed

Abduo, Jaafar; Lyons, Karl M

2017-06-01

Although periodontal factors do not usually have a direct effect on the survival of a fixed prosthesis, harmony between the prosthesis and the periodontium is critical otherwise esthetics, the longevity of the prosthesis and the periodontium will be compromised. A close interdisciplinary relationship between periodontics and prosthodontics is therefore necessary to avoid an unsatisfactory treatment outcome, requiring extensive and expensive retreatment. The design of the prosthesis, the number and quality of the abutment teeth, the preparation and the pontic, the occlusion and the material need to be considered when planning prosthodontic treatment. The location of the preparation margin and the contour and emergence profile of the prosthesis will influence the response of the gingival tissues to the prosthesis. Pontic design and cleansibility also contribute to the response of the gingival tissues as well as to the clinical and esthetic outcome. Even an optimal pontic design will not prevent inflammation of the mucosa adjacent to the pontic if pontic hygiene is not maintained by removal of plaque. Case selection and the patients' ability to carry out adequate oral hygiene are therefore essential for longevity of the prosthesis, and regular reviews provide an opportunity for early detection and treatment of failures. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Design and experimental analysis of a new malleovestibulopexy prosthesis using a finite element model of the human middle ear.

PubMed

Vallejo Valdezate, Luis A; Hidalgo Otamendi, Antonio; Hernández, Alberto; Lobo, Fernando; Gil-Carcedo Sañudo, Elisa; Gil-Carcedo García, Luis M

2015-01-01

Many designs of prostheses are available for middle ear surgery. In this study we propose a design for a new prosthesis, which optimises mechanical performance in the human middle ear and improves some deficiencies in the prostheses currently available. Our objective was to design and assess the theoretical acoustic-mechanical behaviour of this new total ossicular replacement prosthesis. The design of this new prosthesis was based on an animal model (an iguana). For the modelling and mechanical analysis of the new prosthesis, we used a dynamic 3D computer model of the human middle ear, based on the finite elements method (FEM). The new malleovestibulopexy prosthesis design demonstrates an acoustical-mechanical performance similar to that of the healthy human middle ear. This new design also has additional advantages, such as ease of implantation and stability in the middle ear. This study shows that computer simulation can be used to design and optimise the vibroacoustic characteristics of middle ear implants and demonstrates the effectiveness of a new malleovestibulopexy prosthesis in reconstructing the ossicular chain. Copyright © 2014 Elsevier España, S.L.U. y Sociedad Española de Otorrinolaringología y Patología Cérvico-Facial. All rights reserved.

Advanced engineering tools for design and fabrication of a custom nasal prosthesis

NASA Astrophysics Data System (ADS)

Oliveira, Inês; Leal, Nuno; Silva, Pedro; da Costa Ferreira, A.; Neto, Rui J.; Lino, F. Jorge; Reis, Ana

2012-09-01

Unexpected external defects resulting from neoplasms, burns, congenital malformations, trauma or other diseases, particularly when involving partial or total loss of an external organ, can be emotionally devastating. These defects can be restored with prosthesis, obtained by different techniques, materials and methods. The increase of patient numbers and cost constraints lead to the need of exploring new techniques that can increase efficiency. The main goal of this project was to develop a full engineering-based manufacturing process to obtain soft-tissue prosthesis that could provide faster and less expensive options in the manufacturing of customized prosthesis, and at the same time being able to reproduce the highest degree of details, with the maximum comfort for the patient. Design/methodology/approach - This case report describes treatment using silicone prosthesis with an anatomic retention for an 80-years-old woman with a rhinectomy. The proposed methodology integrates non-contact structured light scanning, CT and reverse engineering with CAD/CAM and additive manufacturing technology. Findings - The proposed protocol showed encouraging results since reveals being a better solution for fabricating custom-made facial prostheses for asymmetrical organs than conventional approaches. The process allows the attainment of prosthesis with the minimum contact and discomfort for the patient, disclosing excellent results in terms of aesthetic, prosthesis retention and in terms of time and resources consumed.

Dual-energy CT and ceramic or titanium prostheses material reduce CT artifacts and provide superior image quality of total knee arthroplasty.

PubMed

Kasparek, Maximilian F; Töpker, Michael; Lazar, Mathias; Weber, Michael; Kasparek, Michael; Mang, Thomas; Apfaltrer, Paul; Kubista, Bernd; Windhager, Reinhard; Ringl, Helmut

2018-06-07

To evaluate the influence of different scan parameters for single-energy CT and dual-energy CT, as well as the impact of different material used in a TKA prosthesis on image quality and the extent of metal artifacts. Eight pairs of TKA prostheses from different vendors were examined in a phantom set-up. Each pair consisted of a conventional CoCr prosthesis and the corresponding anti-allergic prosthesis (full titanium, ceramic, or ceramic-coated) from the same vendor. Nine different (seven dual-energy CT and two single-energy CT) scan protocols with different characteristics were used to determine the most suitable CT protocol for TKA imaging. Quantitative image analysis included assessment of blooming artifacts (metal implants appear thicker on CT than they are, given as virtual growth in mm in this paper) and streak artifacts (thick dark lines around metal). Qualitative image analysis was used to investigate the bone-prosthesis interface. The full titanium prosthesis and full ceramic knee showed significantly fewer blooming artifacts compared to the standard CoCr prosthesis (mean virtual growth 0.6-2.2 mm compared to 2.9-4.6 mm, p < 0.001). Dual-energy CT protocols showed less blooming (range 3.3-3.8 mm) compared to single-energy protocols (4.6-5.5 mm). The full titanium and full ceramic prostheses showed significantly fewer streak artifacts (mean standard deviation 77-86 Hounsfield unit (HU)) compared to the standard CoCr prosthesis (277-334 HU, p < 0.001). All dual-energy CT protocols had fewer metal streak artifacts (215-296 HU compared to single-energy CT protocols (392-497 HU)). Full titanium and ceramic prostheses were ranked superior with regard to the image quality at the bone/prosthesis interface compared to a standard CoCr prosthesis, and all dual-energy CT protocols were ranked better than single-energy protocols. Dual-energy CT and ceramic or titanium prostheses reduce CT artifacts and provide superior image quality of total knee arthroplasty at the bone/prosthesis interface. These findings support the use of dual-energy CT as a solid imaging base for clinical decision-making and the use of full-titanium or ceramic prostheses to allow for better CT visualization of the bone-prosthesis interface.

Biomechanical Analysis of a Novel Intercalary Prosthesis for Humeral Diaphyseal Segmental Defect Reconstruction.

PubMed

Zhao, Li-Ming; Tian, Dong-Mu; Wei, Yue; Zhang, Jun-Hui; Di, Zheng-Lin; He, Zhi-Yong; Hu, Yong-Cheng

2018-02-01

To study the biomechanical properties of a novel modular intercalary prosthesis for humeral diaphyseal segmental defect reconstruction, to establish valid finite element humerus and prosthesis models, and to analyze the biomechanical differences in modular intercalary prostheses with or without plate fixation. Three groups were set up to compare the performance of the prosthesis: intact humerus, humerus-prosthesis and humerus-prosthesis-plate. The models of the three groups were transferred to finite element software. Boundary conditions, material properties, and mesh generation were set up for both the prosthesis and the humerus. In addition, 100 N or 2 N.m torsion was loaded to the elbow joint surface with the glenohumeral joint surface fixed. Humeral finite element models were established according to CT scans of the cadaveric bone; reverse engineering software Geomagic was used in this procedure. Components of prosthetic models were established using 3-D modeling software Solidworks. To verify the finite element models, the in vitro tests were simulated using a mechanical testing machine (Bionix; MTS Systems Corporation, USA). Starting with a 50 N preload, the specimen was subjected to 5 times tensile (300 N) and torsional (5 N.m) strength; interval time was 30 min to allow full recovery for the next specimen load. Axial tensile and torsional loads were applied to the elbow joint surface to simulate lifting heavy objects or twisting something, with the glenohumeral joint surface fixed. Stress distribution on the humerus did not change its tendency notably after reconstruction by intercalary prosthesis whether with or without a plate. The special design which included a plate and prosthesis effectively diminished stress on the stem where aseptic loosening often takes place. Stress distribution major concentrate upon two stems without plate addition, maximum stress on proximal and distal stem respectively diminish 27.37% and 13.23% under tension, 10.66% and 11.16% under torsion after plate allied. The novel intercalary prosthesis has excellent ability to reconstruct humeral diaphyseal defects. The accessory fixation system, which included a plate and prosthesis, improved the rigidity of anti-tension and anti-torsion, and diminished the risk of prosthetic loosening and dislocation. A finite element analysis is a kind of convenient and practicable method to be used as the confirmation of experimental biomechanics study. © 2018 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

Flexibility and fatigue evaluation of oblique as compared with anterior lumbar interbody cages with integrated endplate fixation.

PubMed

Freeman, Andrew L; Camisa, William J; Buttermann, Glenn R; Malcolm, James R

2016-01-01

This study was undertaken to quantify the in vitro range of motion (ROM) of oblique as compared with anterior lumbar interbody devices, pullout resistance, and subsidence in fatigue. Anterior and oblique cages with integrated plate fixation (IPF) were tested using lumbar motion segments. Flexibility tests were conducted on the intact segments, cage, cage + IPF, and cage + IPF + pedicle screws (6 anterior, 7 oblique). Pullout tests were then performed on the cage + IPF. Fatigue testing was conducted on the cage + IPF specimens for 30,000 cycles. No ROM differences were observed in any test group between anterior and oblique cage constructs. The greatest reduction in ROM was with supplemental pedicle screw fixation. Peak pullout forces were 637 ± 192 N and 651 ± 127 N for the anterior and oblique implants, respectively. The median cage subsidence was 0.8 mm and 1.4 mm for the anterior and oblique cages, respectively. Anterior and oblique cages similarly reduced ROM in flexibility testing, and the integrated fixation prevented device displacement. Subsidence was minimal during fatigue testing, most of which occurred in the first 2500 cycles.

Effect of joining the sectioned implant-supported prosthesis on the peri-implant strain generated in simulated mandibular model.

PubMed

Singh, Ipsha; Nair, K Chandrasekharan; Shetty, Jayakar

2017-01-01

The aim of this study is to evaluate the strain developed in simulated mandibular model before and after the joining of an implant-supported screw-retained prosthesis by different joining techniques, namely, arc welding, laser welding, and soldering. A specimen simulating a mandibular edentulous ridge was fabricated in heat-cured acrylic resin. 4-mm holes were drilled in the following tooth positions; 36, 33, 43, 46. Implant analogs were placed in the holes. University of California, Los Angeles, abutment was attached to the implant fixture. Eight strain gauges were attached to the acrylic resin model. Six similar models were made. Implant-supported screw-retained fixed prosthesis was fabricated in nickel-chromium alloy. A load of 400 N was applied on the prosthesis using universal testing machine. Resultant strain was measured in each strain gauge. All the prostheses were sectioned at the area between 36 and 33, 33 and 43, and 43 and 46 using 35 micrometer carborundum disc, and strain was measured in each strain gauge after applying a load of 400 N on the prosthesis. Specimens were joined by arc welding, soldering, and laser welding. After joining, a load of 400 N was applied on each prosthesis and the resultant strain was measured in each strain gauge. Highest mean strain values were recorded before sectioning of the prostheses (889.9 microstrains). Lowest mean strain values were recorded after sectioning the prosthesis and before reuniting it (225.0 microstrains). Sectioning and reuniting the long-span implant prosthesis was found to be a significant factor in influencing the peri-implant strain.

Sexual Function and Quality of Life Before and After Penile Prosthesis Implantation Following Radial Forearm Flap Phalloplasty.

PubMed

Young, Ezekiel E; Friedlander, Daniel; Lue, Kathy; Anele, Uzoma A; Khurgin, Jacob L; Bivalacqua, Trinity J; Burnett, Arthur L; Redett, Richard J; Gearhart, John P

2017-06-01

To provide sexual function and quality of life outcomes in patients with severe penile deficiency who underwent radial forearm flap phalloplasty with and without penile prosthesis implantation. Patients with history of severe penile deficiency who underwent microsurgical radial forearm flap phalloplasty with and without penile prosthesis implantation between 2007 and 2014 were identified. They completed a set of web-based validated questionnaires including the International Index of Erectile Function, the Pediatric Penile Perception Score, the Sexual Quality of Life for Men, and several items addressing general quality of life. Outcomes were compared between groups. Nine of the 12 identified patients who had prosthesis after phalloplasty and 4 out of the 7 phalloplasty-only patients completed the survey, resulting in an overall response rate of 68%. Among the phalloplasty-prosthesis patients, 66% reported current sexual activity and 78% reported regular masturbation, whereas 1 of the 4 phalloplasty-only patients reported both. Prosthesis patients scored notably higher in all domains of the International Index of Erectile Function except for sexual desire. In contrast, they demonstrated similar scores of penile perception, as well as general and sexual quality of life. Among patients who have undergone flap phalloplasty, the subsequent placement of penile prosthesis appears to effectively allow for both intercourse and masturbation, resulting in measurable improvements in orgasmic function, intercourse satisfaction, and overall sexual satisfaction. Despite these important benefits, prosthesis placement does not appear to result in improvements in penile perception scores, or general or sexual quality of life. Copyright © 2017 Elsevier Inc. All rights reserved.

The Evolution and Utility of the Small-Carrion Prosthesis, Its Impact, and Progression to the Modern-Day Malleable Penile Prosthesis.

PubMed

Martinez, Daniel R; Terlecki, Ryan; Brant, William O

2015-11-01

Erectile dysfunction has plagued humanity for millennia. For years, treatment had been in the hands of mental health professionals. It was not until the 1970s that urologists created a modality that was marketable, reproducible, and consistently successful at treating impotence, the Small-Carrion Penile Prosthesis. We present the evolution of the malleable/semi-rigid penile prosthesis, concentrating our efforts reviewing and critiquing the pivotal article published by Drs. Michael P. Small, Hernan M. Carrion, and Julian A. Gordon. We then discuss its continued advancement, current-day utilization, and the future of the malleable prosthesis. From the early 1900s, surgeons have been toying with the idea of creating a penile implant. These initial attempts utilized rib cartilage, and eventually synthetic materials, including acrylic, silicone, and polyethylene. In 1975, Drs. Carrion and Small presented their initial experience of 31 patients utilizing their silicone implant. In their manuscript titled, "The Small-Carrion Penile Prosthesis: New Implant for the Management of Impotence," they discuss their technique, perioperative management of complications, and results. The malleable penile prosthesis continued to evolve throughout the years to the current day Genesis and Spectra. Although the current market is dominated by the inflatable penile prosthesis, there are specific situations where the malleable is ideally utilized. The pivotal article by Drs. Carrion and Small helped pave the way for the "New Era" of penile prosthetics and still remains one of the most impactful contributions to the management of erectile dysfunction. © 2015 International Society for Sexual Medicine.

Comparison of Expandable and Fixed Interbody Cages in a Human Cadaver Corpectomy Model: Fatigue Characteristics.

PubMed

Pekmezci, Murat; Tang, Jessica A; Cheng, Liu; Modak, Ashin; McClellan, Robert T; Buckley, Jenni M; Ames, Christopher P

2016-11-01

In vitro cadaver biomechanics study. The goal of this study is to compare the in situ fatigue life of expandable versus fixed interbody cage designs. Expandable cages are becoming more popular, in large part, due to their versatility; however, subsidence and catastrophic failure remain a concern. This in vitro analysis investigates the fatigue life of expandable and fixed interbody cages in a single level human cadaver corpectomy model by evaluating modes of subsidence of expandable and fixed cages as well as change in stiffness of the constructs with cyclic loading. Nineteen specimens from 10 human thoracolumbar spines (T10-L2, L3-L5) were biomechanically evaluated after a single level corpectomy that was reconstructed with an expandable or fixed cage and anterior dual rod instrumentation. All specimens underwent 98 K cycles to simulate 3 months of postoperative weight bearing. In addition, a third group with hyperlordotic cages was used to simulate catastrophic failure that is observed in clinical practice. Three fixed and 2 expandable cages withstood the cyclic loading despite perfect sagittal and coronal plane fitting of the endcaps. The majority of the constructs settled in after initial subsidence. The catastrophic failures that were observed in clinical practice could not be reproduced with hyperlordotic cages. However, all cages in this group subsided, and 60% resulted in endplate fractures during deployment of the cage. Despite greater surface contact area, expandable cages have a trend for higher subsidence rates when compared with fixed cages. When there is edge loading as in the hyperlordotic cage scenario, there is a higher risk of subsidence and intraoperative fracture during deployment of expandable cages.

Design and modeling of Faraday cages for substrate noise isolation

NASA Astrophysics Data System (ADS)

Wu, Joyce H.; del Alamo, Jesús A.

2013-07-01

A Faraday cage structure using through-substrate vias is an effective strategy to suppress substrate crosstalk, particularly at high frequencies. Faraday cages can reduce substrate noise by 32 dB at 10 GHz, and 26 dB at 50 GHz. We have developed lumped-element, equivalent circuit models of the Faraday cages and test structures to better understand the performance of the Faraday cages. These models compare well to measured results and show that the vias of the Faraday cage act as an RLC shunt to ground that draws substrate current. Designing a Faraday cage to achieve optimum isolation requires low via impedance and mitigation of via sidewall capacitance. The Faraday cage inductance is correlated to the number of vias and via spacing of the cage and can be optimized for the frequency of operation.

21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint (hemi-hip) acetabular metal cemented... (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip) acetabular metal cemented prosthesis is a device intended to be implanted to replace a portion of the hip joint...

21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted to...

21 CFR 888.3350 - Hip joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/polymer semi-constrained cemented prosthesis. 888.3350 Section 888.3350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/polymer semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/polymer semi...

21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/composite semi-constrained cemented prosthesis. 888.3340 Section 888.3340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint metal/composite semi-constrained cemented prosthesis. (a) Identification. A hip joint metal...

21 CFR 888.3110 - Ankle joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ankle joint metal/polymer semi-constrained cemented prosthesis. 888.3110 Section 888.3110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Ankle joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An ankle joint metal...

21 CFR 888.3160 - Elbow joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Elbow joint metal/polymer semi-constrained cemented prosthesis. 888.3160 Section 888.3160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Elbow joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An elbow joint metal...

21 CFR 888.3800 - Wrist joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wrist joint metal/polymer semi-constrained... Wrist joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A wrist joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a wrist joint...

21 CFR 888.3110 - Ankle joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ankle joint metal/polymer semi-constrained... Ankle joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an ankle...

21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a device...

21 CFR 888.3120 - Ankle joint metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ankle joint metal/polymer non-constrained cemented... metal/polymer non-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer non... December 26, 1996 for any ankle joint metal/polymer non-constrained cemented prosthesis that was in...

21 CFR 888.3350 - Hip joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer semi-constrained cemented prosthesis. 888.3350 Section 888.3350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/polymer semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/polymer semi...

21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended to...

21 CFR 888.3160 - Elbow joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Elbow joint metal/polymer semi-constrained... Elbow joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An elbow joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an elbow...

21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted to...

21 CFR 888.3170 - Elbow joint radial (hemi-elbow) polymer prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Elbow joint radial (hemi-elbow) polymer prosthesis. 888.3170 Section 888.3170 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (hemi-elbow) polymer prosthesis. (a) Identification. An elbow joint radial (hemi-elbow) polymer...

21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be implanted...

21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made of...

21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended to...

21 CFR 888.3170 - Elbow joint radial (hemi-elbow) polymer prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Elbow joint radial (hemi-elbow) polymer prosthesis. 888.3170 Section 888.3170 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (hemi-elbow) polymer prosthesis. (a) Identification. An elbow joint radial (hemi-elbow) polymer...

21 CFR 888.3800 - Wrist joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Wrist joint metal/polymer semi-constrained... Wrist joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A wrist joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a wrist joint...

21 CFR 874.3540 - Prosthesis modification instrument for ossicular replacement surgery.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Prosthesis modification instrument for ossicular replacement surgery. 874.3540 Section 874.3540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3540 Prosthesis modification...

21 CFR 874.3540 - Prosthesis modification instrument for ossicular replacement surgery.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Prosthesis modification instrument for ossicular replacement surgery. 874.3540 Section 874.3540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3540 Prosthesis modification...

21 CFR 874.3540 - Prosthesis modification instrument for ossicular replacement surgery.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Prosthesis modification instrument for ossicular replacement surgery. 874.3540 Section 874.3540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3540 Prosthesis modification...

21 CFR 874.3540 - Prosthesis modification instrument for ossicular replacement surgery.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prosthesis modification instrument for ossicular replacement surgery. 874.3540 Section 874.3540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3540 Prosthesis modification...

21 CFR 874.3540 - Prosthesis modification instrument for ossicular replacement surgery.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Prosthesis modification instrument for ossicular replacement surgery. 874.3540 Section 874.3540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3540 Prosthesis modification...

21 CFR 874.3730 - Laryngeal prosthesis (Taub design).

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Laryngeal prosthesis (Taub design). 874.3730 Section 874.3730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3730 Laryngeal prosthesis (Taub design). (a) Identification. A...

21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a device...

21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a device...

21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a device...

21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a device...

21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/composite semi-constrained... Hip joint metal/composite semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/composite semi-constrained cemented prosthesis is a two-part device intended to be implanted to replace a...

21 CFR 888.3170 - Elbow joint radial (hemi-elbow) polymer prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Elbow joint radial (hemi-elbow) polymer prosthesis. 888.3170 Section 888.3170 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (hemi-elbow) polymer prosthesis. (a) Identification. An elbow joint radial (hemi-elbow) polymer...

21 CFR 888.3170 - Elbow joint radial (hemi-elbow) polymer prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Elbow joint radial (hemi-elbow) polymer prosthesis. 888.3170 Section 888.3170 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (hemi-elbow) polymer prosthesis. (a) Identification. An elbow joint radial (hemi-elbow) polymer...

21 CFR 888.3350 - Hip joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/polymer semi-constrained cemented prosthesis. 888.3350 Section 888.3350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/polymer semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/polymer semi...

21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted to...

21 CFR 888.3350 - Hip joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/polymer semi-constrained cemented prosthesis. 888.3350 Section 888.3350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/polymer semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/polymer semi...

21 CFR 888.3110 - Ankle joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ankle joint metal/polymer semi-constrained... Ankle joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an ankle...

21 CFR 888.3160 - Elbow joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Elbow joint metal/polymer semi-constrained... Elbow joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An elbow joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an elbow...

21 CFR 888.3110 - Ankle joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ankle joint metal/polymer semi-constrained... Ankle joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an ankle...

21 CFR 888.3800 - Wrist joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Wrist joint metal/polymer semi-constrained... Wrist joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A wrist joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a wrist joint...

21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted to...

21 CFR 888.3800 - Wrist joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Wrist joint metal/polymer semi-constrained... Wrist joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A wrist joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a wrist joint...

21 CFR 888.3120 - Ankle joint metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ankle joint metal/polymer non-constrained cemented... metal/polymer non-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer non... December 26, 1996 for any ankle joint metal/polymer non-constrained cemented prosthesis that was in...

21 CFR 888.3160 - Elbow joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Elbow joint metal/polymer semi-constrained... Elbow joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An elbow joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an elbow...

21 CFR 888.3160 - Elbow joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Elbow joint metal/polymer semi-constrained... Elbow joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An elbow joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an elbow...

21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended to...

21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted to...

21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended to...

21 CFR 888.3110 - Ankle joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ankle joint metal/polymer semi-constrained... Ankle joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an ankle...

21 CFR 888.3350 - Hip joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/polymer semi-constrained cemented prosthesis. 888.3350 Section 888.3350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/polymer semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/polymer semi...

21 CFR 888.3170 - Elbow joint radial (hemi-elbow) polymer prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Elbow joint radial (hemi-elbow) polymer prosthesis. 888.3170 Section 888.3170 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (hemi-elbow) polymer prosthesis. (a) Identification. An elbow joint radial (hemi-elbow) polymer...

21 CFR 888.3520 - Knee joint femorotibial metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femorotibial metal/polymer non... § 888.3520 Knee joint femorotibial metal/polymer non-constrained cemented prosthesis. (a) Identification. A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended to...

21 CFR 888.3800 - Wrist joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Wrist joint metal/polymer semi-constrained... Wrist joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A wrist joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a wrist joint...

21 CFR 888.3120 - Ankle joint metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... substantially equivalent to an ankle joint metal/polymer non-constrained cemented prosthesis that was in... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ankle joint metal/polymer non-constrained cemented... metal/polymer non-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer non...

21 CFR 888.3120 - Ankle joint metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... substantially equivalent to an ankle joint metal/polymer non-constrained cemented prosthesis that was in... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ankle joint metal/polymer non-constrained cemented... metal/polymer non-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer non...

21 CFR 888.3120 - Ankle joint metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... substantially equivalent to an ankle joint metal/polymer non-constrained cemented prosthesis that was in... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ankle joint metal/polymer non-constrained cemented... metal/polymer non-constrained cemented prosthesis. (a) Identification. An ankle joint metal/polymer non...

Femoral Prosthesis Infection by Rhodotorula mucilaginosa▿

PubMed Central

Savini, Vincenzo; Sozio, Federica; Catavitello, Chiara; Talia, Marzia; Manna, Assunta; Febbo, Fabio; Balbinot, Andrea; Di Bonaventura, Giovanni; Piccolomini, Raffaele; Parruti, Giustino; D'Antonio, Domenico

2008-01-01

This case report is a case history of a femoral prosthesis infection caused by Rhodotorula mucilaginosa in a human immunodeficiency virus patient. Though the pathogenicity of this organism for bone tissue has been previously reported, this is the first reported case of an orthopedic prosthesis infection by this species of the genus Rhodotorula. PMID:18753353

Design and Control of a Pneumatically Actuated Transtibial Prosthesis.

PubMed

Zheng, Hao; Shen, Xiangrong

2015-04-01

This paper presents the design and control of a pneumatically actuated transtibial prosthesis, which utilizes a pneumatic cylinder-type actuator to power the prosthetic ankle joint to support the user's locomotion. The pneumatic actuator has multiple advantages over the traditional electric motor, such as light weight, low cost, and high power-to-weight ratio. The objective of this work is to develop a compact and lightweight transtibial prosthesis, leveraging the multiple advantages provided by this highly competitive actuator. In this paper, the design details of the prosthesis are described, including the determination of performance specifications, the layout of the actuation mechanism, and the calculation of the torque capacity. Through the authors' design calculation, the prosthesis is able to provide sufficient range of motion and torque capacity to support the locomotion of a 75 kg individual. The controller design is also described, including the underlying biomechanical analysis and the formulation of the finite-state impedance controller. Finally, the human subject testing results are presented, with the data indicating that the prosthesis is able to generate a natural walking gait and sufficient power output for its amputee user.

Teflon-wire piston or stainless-steel bucket stapes prosthesis: does it make a difference?

PubMed

Farrior, J B; Temple, A E

1999-04-01

The goal of this study was to determine whether postoperative (implantation of a stapes prosthesis) hearing gain and the amount of air-bone gap overclosure are more improved with the Teflon-wire piston or with the stainless-steel bucket prosthesis. We retrospectively reviewed the outcomes of 82 surgeries that had been performed by the primary author; 41 of these patients had received a Fisch Teflon-wire piston, and 41 had received a Bailey-modified Robinson stainless-steel bucket prosthesis. The mean hearing gain for the patients who received the Teflon-wire piston was 23.3 dB after primary stapes surgery and 20.5 dB after revision surgery. Patients who received the stainless-steel bucket prosthesis experienced a mean hearing gain of 20.7 and 20.3 dB, respectively. Following primary stapes surgery, the air-bone gap overclosure was 4.4 dB with the Teflon-wire piston and 5.2 dB with the stainless-steel bucket prosthesis. There was no statistically significant difference in either hearing gain or air-bone gap overclosure between the two prostheses.

Design and Control of a Pneumatically Actuated Transtibial Prosthesis

PubMed Central

Zheng, Hao; Shen, Xiangrong

2015-01-01

This paper presents the design and control of a pneumatically actuated transtibial prosthesis, which utilizes a pneumatic cylinder-type actuator to power the prosthetic ankle joint to support the user's locomotion. The pneumatic actuator has multiple advantages over the traditional electric motor, such as light weight, low cost, and high power-to-weight ratio. The objective of this work is to develop a compact and lightweight transtibial prosthesis, leveraging the multiple advantages provided by this highly competitive actuator. In this paper, the design details of the prosthesis are described, including the determination of performance specifications, the layout of the actuation mechanism, and the calculation of the torque capacity. Through the authors’ design calculation, the prosthesis is able to provide sufficient range of motion and torque capacity to support the locomotion of a 75 kg individual. The controller design is also described, including the underlying biomechanical analysis and the formulation of the finite-state impedance controller. Finally, the human subject testing results are presented, with the data indicating that the prosthesis is able to generate a natural walking gait and sufficient power output for its amputee user. PMID:26146497

[Experiences with cage combinations for guinea pigs].

PubMed

von Zychlinski, J

1989-01-01

Special cage units described in 1982 for guinea pigs have been used either as cages for small groups of breeding animals or for caging of growing animals. By using these cages the following advantages have been noted; the cage size can be adapted to number, age and body weight of the animals; aggression and panic are avoided by corners, walls and tunnels; economic use of breeding males by mating with more females.

Ammonia and Carbon Dioxide Concentrations in Disposable and Reusable Ventilated Mouse Cages

PubMed Central

Silverman, Jerald; Bays, David W; Cooper, Sheldon F; Baker, Stephen P

2008-01-01

This study compares resuable and disposable individually ventilated mouse cages in terms of the formation of intracage CO2 and NH3. Crl:CD-1(ICR) female mice were placed in either disposable or reusable ventilated cages in a positive pressure animal rack. Intracage CO2 and NH3 were measured once daily for 9 d; temperature and relative humidity were monitored for the first 7 d. Results indicated higher CO2 levels in the rear of the disposable cages and in the front of the reusable cages. This pattern corresponded to where the mice tended to congregate. However, CO2 concentrations did not differ significantly between the 2 cage types. Average CO2 levels in both cage types never exceeded approximately 3000 ppm. Intracage NH3 began to rise in the reusable cages on day 4, reached approximately 50 ppm by day 5 and by day 9 was greater than 150 ppm at the cages' rear sampling port while remaining at approximately 70 ppm at the front sampling port. Intracage NH3 levels in the disposable cages remained less than or equal to 3.2 ppm. Intracage temperature and relative humidity were approximately the same in both cage types. We concluded that the disposable ventilated cage performed satisfactorily under the conditions of the study. PMID:18351723

A hollow definitive obturator fabrication technique for management of partial maxillectomy.

PubMed

Patil, Pravinkumar Gajanan; Patil, Smita Pravinkumar

2012-11-01

Maxillary obturator prosthesis is the most frequent treatment option for management of partial or total maxillectomy. Heavy weight of the obturators is often a dislocating factor. Hollowing the prosthesis to reduce its weight is the well established fact. The alternate technique to hollow-out the prosthesis has been described in this article which is a variation of previously described processing techniques. A pre-shaped wax-bolus was incorporated inside the flasks during packing of the heat-polymerized acrylic resin to automatically create the hollow space. The processing technique described is a single step flasking procedure to construct a closed-hollow-obturator prosthesis as a single unit. To best understand the technique, this article describes management of a patient who had undergone partial maxillectomy secondary to squamous cell carcinoma rehabilitated with a hollow-obturator prosthesis.

A hollow definitive obturator fabrication technique for management of partial maxillectomy

PubMed Central

Patil, Smita Pravinkumar

2012-01-01

Maxillary obturator prosthesis is the most frequent treatment option for management of partial or total maxillectomy. Heavy weight of the obturators is often a dislocating factor. Hollowing the prosthesis to reduce its weight is the well established fact. The alternate technique to hollow-out the prosthesis has been described in this article which is a variation of previously described processing techniques. A pre-shaped wax-bolus was incorporated inside the flasks during packing of the heat-polymerized acrylic resin to automatically create the hollow space. The processing technique described is a single step flasking procedure to construct a closed-hollow-obturator prosthesis as a single unit. To best understand the technique, this article describes management of a patient who had undergone partial maxillectomy secondary to squamous cell carcinoma rehabilitated with a hollow-obturator prosthesis. PMID:23236579

A new biomechanical hand prosthesis controlled by surface electromyographic signals.

PubMed

Andrade, Nei A; Borges, Geovany A; de O Nascimento, Francisco A; Romariz, Alexandre R S; da Rocha, Adson F

2007-01-01

This paper describes the development of a low-cost hand prosthesis for use in patients with an amputated hand due to congenital problems or to trauma wound, who possess a part or the forearm endowed with muscular activity. The paper covers the constructive aspects of both mechanical and electronic designs. The prototype is controlled by electromyographic signals measured at the remaining part of the injured limb of the patient. The EMG signals are measured at the surface of the skin, at a point that is close to a working muscle of the amputated arm. The prosthesis allows the patient to hold objects by means of a three finger clamp. The prosthesis presented an excellent performance in preliminary tests with an amputated patient. These tests showed that the prosthesis had a very good performance regarding force and speed.

Transition from a fixed implant dental prosthesis to an implant overdenture in an edentulous patient: a clinical report.

PubMed

Ali, Bolouri; Bhavani, Venkatachalam

2014-09-01

The lack of planning before implant placement and restoration in edentulous patients can lead to a number of problems. Prosthodontists are often faced with the challenge of re-treating patients who have only recently been treated. Although many reports discuss retreatment by fabricating all new prosthetic components, few discuss salvaging parts of the patient's existing prosthesis. This report details the treatment of an edentulous patient who presented with an implant-retained fixed dental prosthesis in the maxillary arch and no opposing prosthesis. The transition from an implant-retained fixed dental prosthesis to a removable implant- and tissue-supported overdenture that uses the patient's existing computer-aided design/computer-aided manufacturing milled titanium substructure is described. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Vent-induced prosthetic leaflet thrombosis treated by open-heart valve-in-valve implantation.

PubMed

Stamm, Christof; Pasic, Miralem; Buz, Semih; Hetzer, Roland

2015-09-01

A patient required emergency mitral valve replacement and extracorporeal membrane oxygenation (ECMO) support for acute biventricular failure. The left ventricular (LV) vent inserted via the left upper pulmonary vein induced thrombotic immobilization of a prosthetic valve leaflet, with significant intra-prosthesis regurgitation after ECMO explantation. Therefore, the left atrium was opened on the beating heart during conventional extracorporeal circulation, all prosthesis leaflets were excised and a 29-mm expandable Edwards Sapien prosthesis was inserted within the scaffold of the original prosthesis under direct vision. This case illustrates the benefits and potential problems of LV venting on ECMO support, and a rapid and safe way of replacing the prosthesis leaflets in a critical situation. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Rehabilitation with dental prosthesis can increase cerebral regional blood volume.

PubMed

Miyamoto, Ikuya; Yoshida, Kazuya; Tsuboi, Yoichi; Iizuka, Tadahiko

2005-12-01

Treatment with denture for edentulous people is highly important for maintaining quality of life. However, its effect on the brain is unknown. In this experimental study, we hypothesized that dental prosthesis can recover not only the physical condition of mastication system but also the regional brain activity. We evaluated functional brain imaging of edentulous subjects fixed by dental implant prosthesis with clenching tasks by multi-channel near-infrared optical topography. Results revealed a significantly (P<0.001; paired t-test) increased cerebral regional blood volume during maximum voluntary clenching task by implant-retained prosthesis. There were no statistically significant differences between patients with and without prosthesis in the latency to the maximum regional blood volume after the task. Conclusively, clenching can be effective for increasing cerebral blood volume; accordingly maintenance of normal chewing might prevent the brain from degenerating.

Measurements of drag and lift on smooth balls in flight

NASA Astrophysics Data System (ADS)

Cross, Rod; Lindsey, Crawford

2017-07-01

Measurements are presented on the drag and lift coefficients for three relatively smooth balls launched in air and tracked with two cameras separated horizontally by 6.4 m. The ball spin was varied in order to investigate whether the Magnus force would increase or decrease when the ball spin was increased. For one ball, the Magnus force increased. For another ball, the Magnus force decreased almost to zero after reaching a maximum. For the third ball, the Magnus force was negative at low ball spins and positive at high ball spins. For one of the balls, the ball spin increased with time as it travelled through the air.

Effects of Furnished Cage Type on Behavior and Welfare of Laying Hens.

PubMed

Li, Xiang; Chen, Donghua; Li, Jianhong; Bao, Jun

2016-06-01

This study was conducted to compare the effects of layout of furniture (a perch, nest, and sandbox) in cages on behavior and welfare of hens. Two hundred and sixteen Hyline Brown laying hens were divided into five groups (treatments) with four replicates per group: small furnished cages (SFC), medium furnished cages type I (MFC-I), medium furnished cages type II (MFC-II), and medium furnished cages type III (MFC-III) and conventional cages (CC). The experiment started at 18 week of age and finished at 52 week of age. Hens' behaviors were filmed during the following periods: 8:00 to 10:00; 13:00 to 14:00; 16:00 to 17:00 on three separate days and two hens from each cage were measured for welfare parameters at 50 wk of age. The results showed that feeding and laying of all hens showed no effect by cage type (p>0.05), and the hens in the furnished cages had significantly lower standing and higher walking than CC hens (p<0.05). The birds in MFC-III had significant higher preening, scratching and feather-pecking behavior than in the other cages (p<0.05). No difference in nesting behavior was found in the hens between the furnished cages (p>0.05). The hens in MFC-I, -II, and -III showed a significant higher socializing behavior than SFC and CC (p<0.05). The lowest perching was for the hens in SFC and the highest perching found for the hens in MFC-III. Overall, the hens in CC showed poorer welfare conditions than the furnished cages, in which the feather condition score, gait score and tonic immobility duration of the hens in CC was significantly higher than SFC, MFC-I, MFC-II, and MFC-III (p<0.05). In conclusion, the furnished cage design affected both behavior and welfare states of hens. Overall, MFC-III cage design was better than SFC, MFC-I, and MFC-II cage designs.

Effects of Furnished Cage Type on Behavior and Welfare of Laying Hens

PubMed Central

Li, Xiang; Chen, Donghua; Li, Jianhong; Bao, Jun

2016-01-01

This study was conducted to compare the effects of layout of furniture (a perch, nest, and sandbox) in cages on behavior and welfare of hens. Two hundred and sixteen Hyline Brown laying hens were divided into five groups (treatments) with four replicates per group: small furnished cages (SFC), medium furnished cages type I (MFC-I), medium furnished cages type II (MFC-II), and medium furnished cages type III (MFC-III) and conventional cages (CC). The experiment started at 18 week of age and finished at 52 week of age. Hens’ behaviors were filmed during the following periods: 8:00 to 10:00; 13:00 to 14:00; 16:00 to 17:00 on three separate days and two hens from each cage were measured for welfare parameters at 50 wk of age. The results showed that feeding and laying of all hens showed no effect by cage type (p>0.05), and the hens in the furnished cages had significantly lower standing and higher walking than CC hens (p<0.05). The birds in MFC-III had significant higher preening, scratching and feather-pecking behavior than in the other cages (p<0.05). No difference in nesting behavior was found in the hens between the furnished cages (p>0.05). The hens in MFC-I, −II, and −III showed a significant higher socializing behavior than SFC and CC (p<0.05). The lowest perching was for the hens in SFC and the highest perching found for the hens in MFC-III. Overall, the hens in CC showed poorer welfare conditions than the furnished cages, in which the feather condition score, gait score and tonic immobility duration of the hens in CC was significantly higher than SFC, MFC-I, MFC-II, and MFC-III (p<0.05). In conclusion, the furnished cage design affected both behavior and welfare states of hens. Overall, MFC-III cage design was better than SFC, MFC-I, and MFC-II cage designs. PMID:26954171

One and two hydrogen molecules in the large cage of the structure II clathrate hydrate: quantum translation-rotation dynamics close to the cage wall.

PubMed

Sebastianelli, Francesco; Xu, Minzhong; Kanan, Dalal K; Bacić, Zlatko

2007-07-19

We have performed a rigorous theoretical study of the quantum translation-rotation (T-R) dynamics of one and two H2 and D2 molecules confined inside the large hexakaidecahedral (5(12)6(4)) cage of the sII clathrate hydrate. For a single encapsulated H2 and D2 molecule, accurate quantum five-dimensional calculations of the T-R energy levels and wave functions are performed that include explicitly, as fully coupled, all three translational and the two rotational degrees of freedom of the hydrogen molecule, while the cage is taken to be rigid. In addition, the ground-state properties, energetics, and spatial distribution of one and two p-H2 and o-D2 molecules in the large cage are calculated rigorously using the diffusion Monte Carlo method. These calculations reveal that the low-energy T-R dynamics of hydrogen molecules in the large cage are qualitatively different from that inside the small cage, studied by us recently. This is caused by the following: (i) The large cage has a cavity whose diameter is about twice that of the small cage for the hydrogen molecule. (ii) In the small cage, the potential energy surface (PES) for H2 is essentially flat in the central region, while in the large cage the PES has a prominent maximum at the cage center, whose height exceeds the T-R zero-point energy of H2/D2. As a result, the guest molecule is excluded from the central part of the large cage, its wave function localized around the off-center global minimum. Peculiar quantum dynamics of the hydrogen molecule squeezed between the central maximum and the cage wall manifests in the excited T-R states whose energies and wave functions differ greatly from those for the small cage. Moreover, they are sensitive to the variations in the hydrogen-bonding topology, which modulate the corrugation of the cage wall.

Sagittal Plane Correction Using the Lateral Transpsoas Approach: A Biomechanical Study on the Effect of Cage Angle and Surgical Technique on Segmental Lordosis.

PubMed

Melikian, Rojeh; Yoon, Sangwook Tim; Kim, Jin Young; Park, Kun Young; Yoon, Caroline; Hutton, William

2016-09-01

Cadaveric biomechanical study. To determine the degree of segmental correction that can be achieved through lateral transpsoas approach by varying cage angle and adding anterior longitudinal ligament (ALL) release and posterior element resection. Lordotic cage insertion through the lateral transpsoas approach is being used increasingly for restoration of sagittal alignment. However, the degree of correction achieved by varying cage angle and ALL release and posterior element resection is not well defined. Thirteen lumbar motion segments between L1 and L5 were dissected into single motion segments. Segmental angles and disk heights were measured under both 50 N and 500 N compressive loads under the following conditions: intact specimen, discectomy (collapsed disk simulation), insertion of parallel cage, 10° cage, 30° cage with ALL release, 30° cage with ALL release and spinous process (SP) resection, 30° cage with ALL release, SP resection, facetectomy, and compression with pedicle screws. Segmental lordosis was not increased by either parallel or 10° cages as compared with intact disks, and contributed small amounts of lordosis when compared with the collapsed disk condition. Placement of 30° cages with ALL release increased segmental lordosis by 10.5°. Adding SP resection increased lordosis to 12.4°. Facetectomy and compression with pedicle screws further increased lordosis to approximately 26°. No interventions resulted in a decrease in either anterior or posterior disk height. Insertion of a parallel or 10° cage has little effect on lordosis. A 30° cage insertion with ALL release resulted in a modest increase in lordosis (10.5°). The addition of SP resection and facetectomy was needed to obtain a larger amount of correction (26°). None of the cages, including the 30° lordotic cage, caused a decrease in posterior disk height suggesting hyperlordotic cages do not cause foraminal stenosis. N/A.

Candida albicans, Staphylococcus aureus and Streptococcus mutans colonization in patients wearing dental prosthesis.

PubMed

Baena-Monroy, Tania; Moreno-Maldonado, Víctor; Franco-Martínez, Fernando; Aldape-Barrios, Beatriz; Quindós, Guillermo; Sánchez-Vargas, Luis Octavio

2005-04-01

Denture stomatitis is associated to Candida albicans, different bacteria and other co-factors such as an acid pH, a carbohydrate ingestion increase, different systemic illnesses and pharmacological treatments. The aim of this study was to determine Candida albicans, Staphylococcus aureus and Streptococcus mutans prevalence in the mucous membrane and prosthesis of patients with and without atrophic denture stomatitis and its relationship with other potential clinical co-factors. Saliva was collected from 105 patients (62 female and 43 male) wearing dental prosthesis in order to measure their pH. Oral samples of the mucous membrane and the internal surface of dental prosthesis were taken with sterile cotton to proceed with the microbiological study. The identification of the isolated microorganisms was performed using conventional microbiological methods. Diabetes and Hypertension were the most frequent systemic illnesses. High carbohydrate ingestion was observed in numerous patients. Atrophic denture stomatitis was reported in 50 patients and the pH average in saliva was of 5.2. The presence of C albicans, S. aureus and S. mutans in the mucous membrane and prosthesis was of 51.4%, 52.4% and 67.6%, respectively. C. albicans was isolated in 66.7% from the prosthesis, whereas S. aureus and S. mutans were isolated in 49.5% of those same prosthesis. C. albicans was isolated in 86% of the patients with atrophic denture stomatitis and S. aureus was isolated in a similar percentage (84% of patients). The isolation of S. mutans was less frequent, and it was observed in 16% of the oral samples of these patients. C. albicans, S. aureus and S. mutans frequently colonize the oral mucous of patients wearing dental prosthesis. This illness-bearing condition is more frequent in patients with denture stomatitis, even though dental prosthesis colonization is lower than in the oral mucous.

Biocompatible membrane of PDMS for the new chamber prosthesis stapes.

PubMed

Banasik, Katarzyna; Kwacz, Monika

2016-06-30

Stapes protheses are designed for patients with otosclerosis resulting immobilization or significant reduction of the stapes mobility. All currently used prostheses are called - piston prosthesis. However, its use to stimulate the cochlea is still imperfect. New chamber stapes prosthesis allows the perilymph excitation more effective than the piston prothesis. Moreover, the chamber prosthesis eliminates the common causes of piston-stapedotomy failures. The most important element of the new prosthesis is a flexible membrane. The membrane stiffness should be close to the stiffness of normal annular ligament. This work presents the process of selection of the membrane's thickness and its manufacturing technology. Method A 3D model of the chamber stapes prosthesis was build using Autodesk Inventor 2015. The model was imported to Abacus 6.13 computing environment. During numerical simulations, displacements corresponding to applied loads were calculated and the membrane thickness was adjusted so that its stiffness was the same as the ligament stiffness (~ 120 N/m). The compliance ratios calculated from the load-displacement curves for the membrane and the annular ligament were verified using linear regression analysis. After determining the thickness, the manufacturing technology of the membrane was developed. Results The best similarity between the membrane's and annular ligament's stiffness was achieved for PDMS membrane with the 0,15- mm thickness (similarity ratio R2=0,997752). In this work, the technological parameters of spin-coating process for membrane manufacture are also presented. Summary The proper functioning of the chamber stapes prosthesis requires the PDMS membrane with a thickness of 0,15 mm. The 0,15-mm membrane has the tiffness close to the stiffness of the normal annular ligament. Therefore, the chamber stapes prosthesis provides the perilymph stimulation at the level comparable to the healthy ear. New prosthesis is currently under pre-clinical investigation to optimize the shape of the inner chamber's surface.

Kinematic Analysis of a Posterior-stabilized Knee Prosthesis

PubMed Central

Zhao, Zhi-Xin; Wen, Liang; Qu, Tie-Bing; Hou, Li-Li; Xiang, Dong; Bin, Jia

2015-01-01

Background: The goal of total knee arthroplasty (TKA) is to restore knee kinematics. Knee prosthesis design plays a very important role in successful restoration. Here, kinematics models of normal and prosthetic knees were created and validated using previously published data. Methods: Computed tomography and magnetic resonance imaging scans of a healthy, anticorrosive female cadaver were used to establish a model of the entire lower limbs, including the femur, tibia, patella, fibula, distal femur cartilage, and medial and lateral menisci, as well as the anterior cruciate, posterior cruciate, medial collateral, and lateral collateral ligaments. The data from the three-dimensional models of the normal knee joint and a posterior-stabilized (PS) knee prosthesis were imported into finite element analysis software to create the final kinematic model of the TKA prosthesis, which was then validated by comparison with a previous study. The displacement of the medial/lateral femur and the internal rotation angle of the tibia were analyzed during 0–135° flexion. Results: Both the output data trends and the measured values derived from the normal knee's kinematics model were very close to the results reported in a previous in vivo study, suggesting that this model can be used for further analyses. The PS knee prosthesis underwent an abnormal forward displacement compared with the normal knee and has insufficient, or insufficiently aggressive, “rollback” compared with the lateral femur of the normal knee. In addition, a certain degree of reverse rotation occurs during flexion of the PS knee prosthesis. Conclusions: There were still several differences between the kinematics of the PS knee prosthesis and a normal knee, suggesting room for improving the design of the PS knee prosthesis. The abnormal kinematics during early flexion shows that the design of the articular surface played a vital role in improving the kinematics of the PS knee prosthesis. PMID:25591565

[Rehabilitation by hollow obturator prosthesis immediately after total maxillectomy for malignant tumor].

PubMed

Li, Xiao-ye; Yan, Ai-hui; Hao, Shuai; Li, Wei; Jiang, Xue-jun; Lu, Li; Qin, Xing-jun; Yan, Hai-xin

2011-05-01

The feasibility and clinical effects of hollow obturator prosthesis for the repair of maxillofacial defect immediately after maxillectomy for cancer were assessed. Thirteen patients with T3-4aN0M0 maxillary neoplasm were treated by the prostheses immediately after maxillectomy. According to the 3D-CT reconstruction of nasal sinus, the 3D stereoscopic prototype was constructed before the surgery. Simulating surgery with Surgicare 5.0 software and then the prosthesis 3D stereoscopic model was shaped. The prosthesis was made quickly and precisely with methacrylate resins according to the model and the print mold before surgery, with supplementary tooth at the bottom of prosthesis. In the surgery, the prosthesis was installed instantly after maxillectomy. The patients were followed up at 1, 3 and 6 month after the surgery, respectively. The facial features and the pronunciation clarity were examined and the questionnaires were carried out in the patients, with comparation by paired t-test. The hollow obturator prosthesis would be replaced by permanent prosthesis made of methacrylate resins at 6 month after the surgery. The hollow obturator prostheses were installed accurately and maxillofacial defects were repaired immediately after maxillectomy in the 13 patients. Postoperative follow-up showed there were significant differences in eyeball sagging (t = 4.67, P < 0.05), mid-facial region collapse (t = 5.67, P < 0.05), and pronunciation clarity (t = 16.38, P < 0.05) between patients with and without prostheses. Questionnaires showed that all the patients were satisfied with the retention of prostheses, the improvement of appearance, the improvement of the symptom of water choking and speech definition. Six months after the surgery, the hollow obturator prostheses were replaced smoothly by permanent prostheses in 11 of the 13 patients. The precise and instant repair of maxillofacial defect by prosthesis after maxillectomy can improve survival quality of patient.

A second prosthesis as a procedural rescue option in trans-apical aortic valve implantation.

PubMed

Kempfert, Jörg; Rastan, Ardawan J; Schuler, Gerhard; Linke, Axel; Holzhey, David; van Linden, Arnaud; Mohr, Friedrich-W; Walther, Thomas

2011-07-01

Trans-apical aortic valve implantation (TA-AVI) using the Edwards SAPIEN™ prosthesis has evolved to a routine procedure for selected high-risk elderly patients. In rare cases, misplacement of the SAPIEN™ valve (too low a position), dysfunction of the leaflets or perforation of the interventricular septum (ventricular septal defect, VSD) occurs and requires immediate implantation of a second prosthesis within the first one. Results of this 'bailout' maneuver have not been reported yet. Of 305 TA-AVI procedures, 15 patients required a second prosthesis due to dysfunctional leaflets (n = 6), low position (n = 7), or VSD (n = 2). Mean age was 82.5 ± 1.3 years, mean logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) was 45.5 ± 5.4, and Society of Thoracic Surgeons (STS) Score was 13.5 ± 1.5. All second SAPIEN™ valves could be implanted successfully within the first one. The second prosthesis solved leaflet dysfunction, sealed the VSD (lower position of the second prosthesis), or corrected the initial misplacement (higher position of the second prosthesis) in all patients. Within 30 days, four patients died (low cardiac output n = 3, all with preoperative ejection fraction (EF) <35%; intestinal ischemia n = 1). Intra-operative echocardiogram and angiogram revealed mild paravalvular leak in three and none/trace in 12 patients. Transvalvular gradients were low despite the implantation of the second valve (P(max)/mean 13.7 ± 4.3/6.4 ± 2.0). Placement of a second SAPIEN™ valve is a valuable 'bailout' technique in case of VSD, dysfunctional leaflets, or too low placement of the first prosthesis. The technique leads to an excellent functional result with low transvalvular gradients. The simple, straight, tubular stent design of the SAPIEN™ prosthesis may be the ideal design for such valve-in-valve procedures. Copyright © 2011 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

[Treatment of periprosthetic femoral fractures after total hip arthroplasty with specially constructed retrograde hollow nails].

PubMed

Szalay, G; Meyer, C; Mika, J; Schnettler, R; Thormann, U

2014-12-01

Treatment of periprosthetic fractures by implantation of a specially constructed, retrograde hollow nail which fits over the tip of the prosthesis and becomes locked on it. Periprosthetic femoral fractures with firmly anchored prosthesis shaft after total hip arthroplasty of types B1 and C according to the Vancouver classification. Loosened prosthesis (type B2/B3) and trochanteric fractures (type A). Broken or damaged prosthesis, florid inflammation and soft tissue injuries in the operation field, contracted knee joint, advanced deformation in the knee joint and distal femur, enclosed prosthesis and general contraindications. In a supine position the periprosthetic fracture is exposed via a lateral access. For cemented prostheses the cement is removed around the tip of the prosthesis (at least 2-3 cm) and medullary cavity. Arthrotomy with flexion of the knee joint and marking of the nail entry point. Drill the medullary cavity, retrograde introduction of the nail, visually fit the nail over the tip of the prosthesis and lock the nail with the prosthesis. If necessary use additional spongiosaplasty or also placement of additional cerclages depending on fracture type and size of the defect zone. Lock the nail distally. Use intraoperative radiological imaging to control correct positioning and length of the nail. Close the wound layer by layer with placement of suction drainage devices and dressing. Partial loading for 6 weeks with a subsequent pain-adapted loading gradient until full loading is possible. If selective partial loading is not possible, a decision must be made in individual cases as to whether the intraoperative findings allow immediate full loading. From 2004 to 2011 a total of 25 periprosthetic femoral fractures in 25 patients were treated in 2 locations using specially constructed slotted hollow nails. Within the framework of a retrospective study 20 of these patients (16 female and 4 male; average age 77.2 [72-84] years) were clinically and radiologically re-examined on average 19.3 (7-31) months postoperatively. No postoperative bleeding, wound healing disorders and infections. In all patients there was a loading stable consolidation of the fracture in the correct femoral axis, length and rotation with no evidence for radiological signs of loosening of the prosthesis or dislocation of the nails. In one case there was loosening of the prosthesis which had obviously occurred during the operative procedure. After consolidation of the fracture it was necessary to exchange the prosthesis for a long shafted prosthesis. A comparable situation to the preoperative degree of mobility was found in 12 out of the 20 patients, a moderate deterioration in 5 patients, a substantial residual impairment in 2 patients and an improvement of the situation in 1 patient.

Nasal Histopathology and Intracage Ammonia Levels in Female Groups and Breeding Mice Housed in Static Isolation Cages

PubMed Central

Mexas, Angela M; Brice, Angela K; Caro, Adam C; Hillanbrand, Troy S

2015-01-01

Many factors influence ammonia levels in rodent cages, and high intracage ammonia has been associated with specific types of abnormal nasal pathology in mice. The use of autoclaved corncob bedding and the maintenance of low room humidity reduce the accumulation of ammonia in mouse cages. However, there are no engineering standards that define the limits of ammonia exposure for mice housed in static isolation cages. Regulatory guidance indicates that solid bottom cages must be sanitized at least weekly and that cage components in direct contact with animals must be sanitized at least every 2 wk. Common practice is to replace the bottoms and bedding of static isolation cages once weekly. To determine whether changing static isolation cages once weekly is an appropriate performance standard for mice, we prospectively evaluated the relationship between ammonia levels, nasal histopathology, and housing densities in various grouping strategies of mice housed in static isolation cages. Here, we report that the average nasal pathology score per cage and intracage ammonia levels were correlated, but nasal pathology scores did not differ among mice housed in breeding pairs, breeding trios, or female groups. In light of ammonia levels and histopathology scores as performance standards, these results suggest that a weekly cage-change frequency for static isolation cages does not result in adverse effects. Our results provide evidence to support current practices in the use of static isolation cages for housing laboratory mice in modern vivaria. PMID:26424245

Disparities in Ammonia, Temperature, Humidity, and Airborne Particulate Matter between the Micro-and Macroenvironments of Mice in Individually Ventilated Caging

PubMed Central

Rosenbaum, Matthew D; VandeWoude, Susan; Volckens, John; Johnson, Thomas E

2010-01-01

Animal room environmental parameters typically are monitored with the assumption that the environment within the cage closely mirrors the room environment. This study evaluated that premise by examining macro- (room) and microenvironmental (cage) parameters in individually ventilated cages housing mice with variable amounts of bedding over a period of 17 d without cage changes. Intracage ammonia levels remained within recommended human guidelines but were higher than room levels, confirming that microisolation caging is efficient at preventing ammonia generated from animal waste from escaping into the room. Humidity and temperature within cages were consistently higher than room levels. Particles in the room predominantly consisted of fine particles (diameter less than 2.5 µm), presumably from the ambient atmosphere; some of these particles were found in the cage microenvironment. In addition, mouse activity within cages produced larger particles, and these particles contributed to substantially higher aerosol mass concentrations within the cage. These findings demonstrate that, although cage and room environmental parameters differ, knowledge of room environmental conditions can be used to predict certain conditions within the cage. This association is relevant in that typical animal care standard operating procedures rely on room measurements, not intracage measurements, which arguably are more important for assessing animal welfare. Further, location and ambient climate can influence particle concentrations in the room, and consequently within the animal cage, suggesting local weather patterns and air quality may account for variability among studies conducted at sites that are geographically divergent. PMID:20353692

Calfplasty.

PubMed

Felício, Y

2000-01-01

The author describes a method of calf augmentation by a silicone prosthesis implant for correction of asymmetrical legs or aesthetic problems. Preference is given to the placement of soft silicone implants (Glitzentein implants); they are more natural looking than hard implants. The implants are placed over both heads of the gastrocnemius muscle or beneath the fascia cruris superficialis. Operations were performed from November 1985 to August 1999. One hundred patients were studied: 95 female and 5 male. Two hundred calf implants were performed: 188 soft implants (Glitzenstein), 6 hard implants (Aiache), and 6 together on the same leg (Glitzenstein and Aiache implants). No infection problems, prosthesis rupture, or hematomas occurred. There were four seromas, but they disappeared in 15 days. Four prostheses were removed in two patients who did not like the final result. One prosthesis changed place, to the upper part of the calf. The operation is performed under sedative and local anesthesia, with an incision of approximately 4 to 5 cm in the popliteal pleat, at the same height as the fascia cruris. To date, no functional problem or muscular dysfunction has been provoked by silicone prosthesis implants. The patient walks 8 h after the surgery. We selected 500 patients who received implants in the legs with calf prostheses, fat implants, and prosthesis and fat implant together, during 14 years of follow-up, but the focus of this paper is a calf implant with prosthesis in 100 patients with 200 calf prosthesis implants.

Function of obturator prosthesis after maxillectomy and prosthetic obturator rehabilitation.

PubMed

Chen, Cheng; Ren, Wenhao; Gao, Ling; Cheng, Zheng; Zhang, Linmei; Li, Shaoming; Zhi, Pro Ke-qian

2016-01-01

Maxillary defects are usually rehabilitated by a prosthetic obturator. This study aimed to evaluate the functioning of obturators prosthesis in patients with unilateral defects after maxillectomy. Of 49 patients, 28 underwent to maxillectomy as a result of tumor ablative surgery, and acquired unilateral maxillary defects. Evaluation of the function was performed by applying the Obturator Functional Scale (OFS). From a total of 49 patients, 28 were treated as follows: 9 with a conventional retained obturator prosthesis (COP), 11 (39%) with an enhanced retentive obturator prosthesis with stud attachment (POP) and 8 (28%) with an enhanced retentive obturator prosthesis with magnetic attachment (POM). The mean OFS score was 80. Scores on functions of speech, swallowing and chewing reached statistical significances (p<0.05) among these three subgroups. Comparing COP and MOP groups, the scores of OFS in the domains of "Speech-ability to speak in public" and "Swallowing-leakage with liquids" were significantly higher in AOP group. Comparing COP group, the scores of OFS in "Swallowing-leakage with solid" and "Chewing/eating" domains were increased significantly (p<0.05) both in MOP and AOP groups. Obturator prosthesis improves oral function of patients after maxillary defects; the retention of the obturator prosthesis enhanced by the addition of attachments showed more benefits in oral function. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Percutaneous coronary angioplasty of a left anterior descending artery implanted on a Dacron coronary prosthesis on an aortic conduit.

PubMed

Drobinski, G; Thomas, D; Funck, F; Metzger, J P; Canny, M; Grosgogeat, Y

1986-08-01

Certain surgical techniques may make it difficult to catheterize the coronary ostia and perform percutaneous coronary angioplasty. We report the case of a 48 year old patient who developed unstable angina four years after a Bentall's procedure with reimplantation of the coronary arteries on a Dacron coronary prosthesis. The anginal pain was related to very severe stenosis of the proximal segment of the left anterior descending artery. The difficulties encountered during the dilatation procedure were due to: (a) the ectopic position of the ostium of the prosthesis on the anterior aortic wall; (b) the forces exerted on the aortic prosthesis wall and on the valvular prosthesis during positioning of the guiding catheter which were poorly tolerated and induced a vagal reaction; (c) the direction taken by the distal tip of the guiding catheter, perpendicular to the wall of the aortic prosthesis; (d) the sinuosity of the arterial trajectory: the left coronary segment of the coronary prosthesis was directed towards the left circumflex artery rather than towards the left anterior descending artery. Coronary angioplasty succeeded after relatively complex technical procedures: special guiding catheter, unusual intra-aortic manoeuvres for positioning the guiding catheter, dilatation catheter change on a 3-metre long guide wire in order to cross the stenotic segment; this was performed with a super low-profiled dilatation catheter. There were no complications and anginal pain disappeared.

Bionic ankle–foot prosthesis normalizes walking gait for persons with leg amputation

PubMed Central

Herr, Hugh M.; Grabowski, Alena M.

2012-01-01

Over time, leg prostheses have improved in design, but have been incapable of actively adapting to different walking velocities in a manner comparable to a biological limb. People with a leg amputation using such commercially available passive-elastic prostheses require significantly more metabolic energy to walk at the same velocities, prefer to walk slower and have abnormal biomechanics compared with non-amputees. A bionic prosthesis has been developed that emulates the function of a biological ankle during level-ground walking, specifically providing the net positive work required for a range of walking velocities. We compared metabolic energy costs, preferred velocities and biomechanical patterns of seven people with a unilateral transtibial amputation using the bionic prosthesis and using their own passive-elastic prosthesis to those of seven non-amputees during level-ground walking. Compared with using a passive-elastic prosthesis, using the bionic prosthesis decreased metabolic cost by 8 per cent, increased trailing prosthetic leg mechanical work by 57 per cent and decreased the leading biological leg mechanical work by 10 per cent, on average, across walking velocities of 0.75–1.75 m s−1 and increased preferred walking velocity by 23 per cent. Using the bionic prosthesis resulted in metabolic energy costs, preferred walking velocities and biomechanical patterns that were not significantly different from people without an amputation. PMID:21752817

[Pelvic reconstructions after bone tumor resection].

PubMed

Anract, Philippe; Biau, David; Babinet, Antoine; Tomeno, Bernard

2014-02-01

The three more frequent primitive malignant bone tumour which concerned the iliac bone are chondrosarcoma, following Ewing sarcoma and osteosarcoma. Wide resection remains the most important part of the treatment associated with chemotherapy for osteosarcoma and the Ewing sarcoma. Iliac wing resections and obdurate ring don't required reconstruction. However, acetabular resections and iliac wing resection with disruption of the pelvic ring required reconstruction to provide acceptable functional result. Acetabular reconstruction remains high technical demanding challenge. After isolated acetabular resection or associated to obdurate ring, our usual method of reconstruction is homolateral proximal femoral autograft and total hip prosthesis but it is possible to also used : saddle prosthesis, Mac Minn prosthesis with auto or allograft, modular prosthesis or custom made prosthesis, massive allograft with or without prosthesis and femoro-ilac arthrodesis. After resection of the iliac wing plus acetabulum, reconstruction can be performed by femoro-obturatrice and femora-sacral arthrodesis, homolateral proximal femoral autograft and prosthesis, femoral medialisation, massive allograft and massive allograft. Carcinological results are lesser than resection for distal limb tumor, local recurrence rate range 17 to 45%. Functional results after Iliac wing and obdurate ring are good. However, acetabular reconstruction provide uncertain functional results. The lesser results arrive after hemipelvic or acetabular and iliac wing resection-reconstruction, especially when gluteus muscles were also resected. The most favourable results arrive after isolated acetabular or acetabular plus obturateur ring resection-reconstruction.

Designing optimal stimuli to control neuronal spike timing

PubMed Central

Packer, Adam M.; Yuste, Rafael; Paninski, Liam

2011-01-01

Recent advances in experimental stimulation methods have raised the following important computational question: how can we choose a stimulus that will drive a neuron to output a target spike train with optimal precision, given physiological constraints? Here we adopt an approach based on models that describe how a stimulating agent (such as an injected electrical current or a laser light interacting with caged neurotransmitters or photosensitive ion channels) affects the spiking activity of neurons. Based on these models, we solve the reverse problem of finding the best time-dependent modulation of the input, subject to hardware limitations as well as physiologically inspired safety measures, that causes the neuron to emit a spike train that with highest probability will be close to a target spike train. We adopt fast convex constrained optimization methods to solve this problem. Our methods can potentially be implemented in real time and may also be generalized to the case of many cells, suitable for neural prosthesis applications. With the use of biologically sensible parameters and constraints, our method finds stimulation patterns that generate very precise spike trains in simulated experiments. We also tested the intracellular current injection method on pyramidal cells in mouse cortical slices, quantifying the dependence of spiking reliability and timing precision on constraints imposed on the applied currents. PMID:21511704

21 CFR 888.3358 - Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer/metal semi-constrained... Devices § 888.3358 Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis. (a) Identification. A hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis is a device...

21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint femoral (hemi-hip) metal/polymer... § 888.3390 Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis is a two-part...

Elimination of Subsidence with 26-mm-Wide Cages in Extreme Lateral Interbody Fusion.

PubMed

Lang, Gernot; Navarro-Ramirez, Rodrigo; Gandevia, Lena; Hussain, Ibrahim; Nakhla, Jonathan; Zubkov, Micaella; Härtl, Roger

2017-08-01

Extreme lateral interbody fusion (ELIF) has gained popularity as a minimally invasive technique for indirect decompression. However, graft subsidence potentially threatens long-term success of ELIF. This study evaluated whether 26-mm-wide cages can eliminate subsidence and subsequent loss of decompression in ELIF. Patients undergoing ELIF surgery using a 26-mm-wide cage were analyzed retrospectively. Patient demographics and perioperative data for radiographic and clinical outcomes were recorded. Radiographic parameters included regional sagittal lumbar lordosis and foraminal and disc height. Clinical parameters were evaluated using the Oswestry Disability Index and visual analog scale. Subsidence of 26-mm-wide cages was compared with previous outcomes of patients undergoing ELIF using 18-mm-wide and 22-mm-wide cages. There were 21 patients and 28 spinal segments analyzed. Radiographic outcome measures such as disc and foraminal height revealed significant improvement at follow-up compared with before surgery (P = 0.001). Postoperative to last follow-up cage subsidence translated into 0.34 mm ± 0.26 and -0.55 mm ± 0.64 in disc and foraminal height loss, respectively. Patients with 26-mm-wide cages experienced less subsidence by means of disc (26 mm vs. 18 mm and 22 mm, P ≤ 0.05) and foraminal height (26 mm vs. 18 mm, P = 0.005; 26 mm vs. 22 mm, P = 0.208) loss compared with patients receiving 18-mm-wide and 22-mm-wide cages. The 26-mm-wide cages almost eliminated cage subsidence in ELIF. Compared with 18-mm-wide and 22-mm-wide cages, 26-mm-wide cages significantly reduced cage subsidence in ELIF at midterm follow-up. A 26-mm-wide cage should be used in ELIF to achieve sustained indirect decompression. Copyright © 2017. Published by Elsevier Inc.

Do Lordotic Cages Provide Better Segmental Lordosis Versus Nonlordotic Cages in Lateral Lumbar Interbody Fusion (LLIF)?

PubMed

Sembrano, Jonathan N; Horazdovsky, Ryan D; Sharma, Amit K; Yson, Sharon C; Santos, Edward R G; Polly, David W

2017-05-01

A retrospective comparative radiographic review. To evaluate the radiographic changes brought about by lordotic and nonlordotic cages on segmental and regional lumbar sagittal alignment and disk height in lateral lumbar interbody fusion (LLIF). The effects of cage design on operative level segmental lordosis in posterior interbody fusion procedures have been reported. However, there are no studies comparing the effect of sagittal implant geometry in LLIF. This is a comparative radiographic analysis of consecutive LLIF procedures performed with use of lordotic and nonlordotic interbody cages. Forty patients (61 levels) underwent LLIF. Average age was 57 years (range, 30-83 y). Ten-degree lordotic PEEK cages were used at 31 lumbar interbody levels, and nonlordotic cages were used at 30 levels. The following parameters were measured on preoperative and postoperative radiographs: segmental lordosis; anterior and posterior disk heights at operative level; segmental lordosis at supra-level and subjacent level; and overall lumbar (L1-S1) lordosis. Measurement changes for each cage group were compared using paired t test analysis. The use of lordotic cages in LLIF resulted in a significant increase in lordosis at operative levels (2.8 degrees; P=0.01), whereas nonlordotic cages did not (0.6 degrees; P=0.71) when compared with preoperative segmental lordosis. Anterior and posterior disk heights were significantly increased in both groups (P<0.01). Neither cage group showed significant change in overall lumbar lordosis (lordotic P=0.86 vs. nonlordotic P=0.25). Lordotic cages provided significant increase in operative level segmental lordosis compared with nonlordotic cages although overall lumbar lordosis remained unchanged. Anterior and posterior disk heights were significantly increased by both cages, providing basis for indirect spinal decompression.

Development of furnished cages for laying hens.

PubMed

Appleby, M C; Walker, A W; Nicol, C J; Lindberg, A C; Freire, R; Hughes, B O; Elson, H A

2002-09-01

1. A 3-year trial was carried out of cages for laying hens, occupying a full laying house. The main cage designs used were 5000 cm2 in area, 50 cm high at the rear and furnished with nests and perches. F cages had a front rollaway nest at the side, lined with artificial turf. FD cages also had a dust bath containing sand over the nest. H cages had two nest hollows at the side, one in front of the other. They were compared with conventional cages 2500 cm2 in area and 38 cm high at the rear. 2. Cages were stocked with from 4 to 8 ISA Brown hens per cage, resulting in varied allowances of area, feeder and perch per bird. No birds were beak trimmed. In F and FD cages two further treatments were applied: nests and dust baths were sometimes fitted with gates to exclude birds from dust baths in the morning and from both at night; elevated food troughs, with a lip 33 cm above the cage floor, were compared with standard troughs. 3. Management of the house was generally highly successful, with temperature control achieved by ventilation. Egg production was above breeders' standards and not significantly affected by cage design. More eggs per bird were collected when there were fewer birds per cage but food consumption also then tended to be higher. 4. The number of downgraded eggs was variable, with some tendency for more in furnished cages. Eggs laid in dust baths were often downgraded. Those laid at the back of the cage were frequently dirty because of accumulation of droppings. H nests were unsuccessful, with less than 50% of eggs laid in the nest hollows. However, up to 93% of eggs were laid in front rollaways, and few of these were downgraded. 5. Feather and foot damage were generally less in furnished than in conventional cages, greater where there were more birds per cage. With an elevated food trough there was less feather damage but more overgrowth of claws. In year 2, mortality was greater in cages with more birds. 6. Pre-laying behaviour was mostly settled in front rollaway nests. Dust baths were used more for pecking and scratching than for dust bathing. Comfort behaviour was more frequent in furnished cages than conventional, although still not frequent. Locomotion was strongly affected by number of birds per cage or by space per bird, being reduced by crowding. Most birds perched at night except in one treatment providing only 10.7 cm perch per bird. 7. Behaviour was more unrestricted and varied, and physical condition was better, in furnished than in conventional cages. However, egg production will cost more in furnished cages, partly because more eggs are downgraded. Dust baths must be fitted with gates that the birds cannot open from outside, but gates for nest boxes were found unnecessary. If a low perch is fitted it must be far enough from the back of the cage for birds to walk there. 8. Where there was less space per bird (more birds per cage) than the requirements in the 1999 European Commission Directive on laying hens, there were: fewer eggs per hen, but still above the breeders' target; lower food consumption; more feather and foot damage, but less than in conventional cages; higher mortality in one trial out of three; less freedom of movement. However, the results were still very good even with 8 birds per cage, and support the principle that furnished cages provide an acceptable way of protecting the welfare of laying hens.

Variable Cadence Walking and Ground Adaptive Standing with a Powered Ankle Prosthesis

PubMed Central

Shultz, Amanda H.; Lawson, Brian E.; Goldfarb, Michael

2015-01-01

Abstract This paper describes a control approach that provides walking and standing functionality for a powered ankle prosthesis, and demonstrates the efficacy of the approach in experiments in which a unilateral transtibial amputee subject walks with the prosthesis at variable cadences, and stands on various slopes. Both controllers incorporate a finite-state structure that emulates healthy ankle joint behavior via a series of piecewise passive impedance functions. The walking controller incorporates an algorithm to modify impedance parameters based on estimated cadence, while the standing controller incorporates an algorithm to modulate the ankle equilibrium angle in order to adapt to the ground slope and user posture, and the supervisory controller selects between the walking and standing controllers. The system is shown to reproduce several essential biomechanical features of the healthy joint during walking, particularly relative to a passive prosthesis, and is shown to adapt to variable cadences. The system is also shown to adapt to slopes over a range of ± 15 deg and to provide support to the user in a manner that is biomimetic, as validated by quasi-static stiffness measurements recorded by the prosthesis. Data from standing trials indicate that the user places more weight on the powered prosthesis than on his passive prosthesis when standing on sloped surfaces, particularly at angles of 10 deg or greater. The authors also demonstrated that the prosthesis typically began providing support within 1 s of initial contact with the ground. Further, the supervisory controller was shown to be effective in switching between walking and standing, as well as in determining ground slope just prior to the transition from the standing controller to the walking controller, where the estimated ground slope was within 1.25 deg of the actual ground slope for all trials. PMID:25955789

Clinical Outcome of Medial Pivot Compared With Press-Fit Condylar Sigma Cruciate-Retaining Mobile-Bearing Total Knee Arthroplasty.

PubMed

Kim, Young-Hoo; Park, Jang-Won; Kim, Jun-Shik

2017-10-01

The purpose of this study was to compare the long-term clinical results, radiographic results, range of knee motion, patient satisfaction, and the survival rate of Medial-Pivot posterior cruciate-substituting, knee prosthesis and a press-fit condylar (PFC) Sigma cruciate-retaining mobile-bearing knee prosthesis in the same patients. One hundred eighty-two patients received Medial-Pivot knee prosthesis in one knee and a PFC Sigma knee prosthesis in the contralateral knee. The minimum duration of follow-up was 11 years (range, 11-12.6 years). The knees with a Medial-Pivot knee prosthesis had significantly worse results than those with a PFC Sigma knee prosthesis at the final follow-up with regard to the mean postoperative Knee Society knee scores (90 compared with 95 points), Western Ontario and McMaster Universities Osteoarthritis Index score (25 compared with 18 points), and range of knee motion (117° compared with 128°). Patients were more satisfied with PFC Sigma knee prosthesis (93%) than with Medial-Pivot knee prosthesis (75%). Complication rates were significantly higher in the Medial-Pivot knee group (26%) than those in the PFC Sigma knee group (6.5%). Radiographic results and survival rates (99% compared with 99.5%) were similar between the 2 groups. Although the long-term fixation and survival rate of both Medial-Pivot and PFC Sigma prostheses were similar, we observed a worse knee score, worse range of knee motion, and patient satisfaction was less in the Medial-Pivot knee group than in the PFC Sigma knee group. Furthermore, complication rate was also higher in the Medial-Pivot knee group than the other group. Copyright © 2017 Elsevier Inc. All rights reserved.