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1

Cementless large-head metal-on-metal total hip arthroplasty in patients younger than 60 years—A multicenter early result  

Microsoft Academic Search

Large-head metal-on-metal total hip arthroplasty has the theoretical advantages of less wear and better range of motion than traditional polyethylene bearings and seems to be a better choice for young and active patients. We conducted a retrospective study and reported the early results of using such prostheses in 59 patients (70 hips) with a mean age of 43.1 years (range,

Po-Ting Wu; Chih-Jen Wang; Cheng-Yo Yen; Ji-Shen Jian; Kuo-An Lai

2

Material loss at the taper junction of retrieved large head metal-on-metal total hip replacements.  

PubMed

It has been speculated that material loss, either as corrosion or wear, at the head-stem taper junction is implicated in the high revision rates reported for metal-on-metal total hip replacements. We measured the volume of material loss from the taper and bearing surfaces of retrieved devices, and investigated the associations with blood metal ion levels and the diagnosis of a cystic or solid pseudotumor. The median volumes of material lost from the female and male taper surfaces were 2.0 and 0.29?mm(3) , respectively, while the median volumes of wear from the cup and head bearing surfaces were 1.94 and 3.44?mm(3) , respectively. Material loss from the female taper was similar to that from the acetabular bearing surface (p?=?0.55), but significantly less than that from the femoral bearing surface (p?

Matthies, Ashley K; Racasan, Radu; Bills, Paul; Blunt, Liam; Cro, Suzie; Panagiotidou, Anna; Blunn, Gordon; Skinner, John; Hart, Alister J

2013-08-05

3

Cementless large-head metal-on-metal total hip arthroplasty in patients younger than 60 years--a multicenter early result.  

PubMed

Large-head metal-on-metal total hip arthroplasty has the theoretical advantages of less wear and better range of motion than traditional polyethylene bearings and seems to be a better choice for young and active patients. We conducted a retrospective study and reported the early results of using such prostheses in 59 patients (70 hips) with a mean age of 43.1 years (range, 23-59 years) at the time of surgery. Osteonecrosis of the femoral head accounted for most diagnoses. Harris Hip Scores and hip range of motion both significantly improved (p<0.001) at an average follow-up of 32.6 months (range, 24-48 months). Only one intraoperative calcar fissure was encountered, and it was fixated by cerclage wiring; there was no infection, dislocation, or osteolysis around either the cup or the stem at the latest follow-up. A postoperative gap in the acetabular component was noted in 24 hips, with a mean depth of 1.11 mm, but this was not correlated with the functional score (p=0.291). Transient thigh pain, which resolved after 6 months, was observed in six patients but was not related to either the postoperative gap or cup inclination (p=1.000 and p=0.664, respectively). All patients resumed their original jobs and recreational activities with little discomfort. Thus far, large-head metal-on-metal total hip arthroplasty has shown excellent early results. The long-term results and the effects of metal debris and potentially elevated serum metal ion levels require further observation. PMID:22226059

Wu, Po-Ting; Wang, Chih-Jen; Yen, Cheng-Yo; Jian, Ji-Shen; Lai, Kuo-An

2011-09-15

4

Metal on metal total hip arthroplasty using modular acetabular shells.  

PubMed

Metal on metal bearings were reintroduced into the United States for use in total hip arthroplasty approximately a decade ago. We evaluated a consecutive series cohort of 148 patients with 169 hips who underwent THR using a metal on metal bearing surface with a modular acetabular shell that had fixation augmentation with dome screws. At 3 to 8 year follow-up, average 4.7 years, only one component was revised (for femoral loosening). 3 hips demonstrated proximal femoral osteolysis and 3 hips demonstrated pelvic osteolysis. The average follow-up Harris Hip Score was 94 (range, 57-100). Although the results have been excellent, we continue to closely monitor these hips for any long term failures, or concerns. PMID:23489729

Liudahl, Adam A; Liu, Steve S; Goetz, Devon D; Mahoney, Craig R; Callaghan, John J

2013-03-13

5

The benefits of metal-on-metal total hip replacements.  

PubMed

The Müller's cast prosthesis with a concentric metal-on-metal articulation and 3 sliding bearings was used in Switzerland from 1965 to 1967. During the next 10 to 15 years, a number of hips in which the metal-to-metal systems were implanted were revised. Rather than osteoporosis and cranial migration occurring, the acetabular roofs were often sclerotic and the components showed no or only minor migration. At surgery, the capsule was almost normal and without signs of inflammation. Histologically, the capsule did not show the usual masses of giant cells associated with polyethylene particles. In the mid-1980s, different designs of metal-on-metal articulations were tested. From 1987 to 1990, this author developed, together with the biomaterial division of Sulzer Medical Technology, a pure titanium shell with a polyethylene-backed 28-mm forged cobalt-chromium liner insert. This combination has been successful, with no revisions required to date. In summary, with the present metal-on-metal articulations it is now possible to stop using the polyethylene. The successful long-term results of the cast cobalt-chromium metal-on-metal articulations of 1966 hold much promise for the future of the new-forged, more-precise, metallic socket. PMID:7634591

Müller, M E

1995-02-01

6

Metal-on-Metal Total Hip Resurfacing Arthroplasty  

PubMed Central

Executive Summary Objective The objective of this review was to assess the safety and effectiveness of metal on metal (MOM) hip resurfacing arthroplasty for young patients compared with that of total hip replacement (THR) in the same population. Clinical Need Total hip replacement has proved to be very effective for late middle-aged and elderly patients with severe degenerative diseases of the hips. As indications for THR began to include younger patients and those with a more active life style, the longevity of the implant became a concern. Evidence suggests that these patients experience relatively higher rates of early implant failure and the need for revision. The Swedish hip registry, for example, has demonstrated a survival rate in excess of 80% at 20 years for those aged over 65 years, whereas this figure was 33% by 16 years in those aged under 55 years. Hip resurfacing arthroplasty is a bone-conserving alternative to THR that restores normal joint biomechanics and load transfer. The technique has been used around the world for more than 10 years, specifically in the United Kingdom and other European countries. The Technology Metal-on-metal hip resurfacing arthroplasty is an alternative procedure to conventional THR in younger patients. Hip resurfacing arthroplasty is less invasive than THR and addresses the problem of preserving femoral bone stock at the initial operation. This means that future hip revisions are possible with THR if the initial MOM arthroplasty becomes less effective with time in these younger patients. The procedure involves the removal and replacement of the surface of the femoral head with a hollow metal hemisphere, which fits into a metal acetabular cup. Hip resurfacing arthroplasty is a technically more demanding procedure than is conventional THR. In hip resurfacing, the femoral head is retained, which makes it much more difficult to access the acetabular cup. However, hip resurfacing arthroplasty has several advantages over a conventional THR with a small (28 mm) ball. First, the large femoral head reduces the chance of dislocation, so that rates of dislocation are less than those with conventional THR. Second, the range of motion with hip resurfacing arthroplasty is higher than that achieved with conventional THR. A variety of MOM hip resurfacing implants are used in clinical practice. Six MOM hip resurfacing implants have been issued licences in Canada. Review Strategy A search of electronic bibliographies (OVID Medline, Medline In-Process and Other Non-Indexed Citations, Embase, Cochrane CENTRAL and DSR, INAHTA) was undertaken to identify evidence published from Jan 1, 1997 to October 27, 2005. The search was limited to English-language articles and human studies. The literature search yielded 245 citations. Of these, 11 met inclusion criteria (9 for effectiveness, 2 for safety). The result of the only reported randomized controlled trial on MOM hip resurfacing arthroplasty could not be included in this assessment, because it used a cemented acetabular component, whereas in the new generation of implants, a cementless acetabular component is used. After omitting this publication, only case series remained. Summary of Findings   Health Outcomes The Harris hip score and SF-12 are 2 measures commonly used to report health outcomes in MOM hip resurfacing arthroplasty studies. Other scales used are the Oxford hip score and the University of California Los Angeles hip score. The case series showed that the mean revision rate of MOM hip resurfacing arthroplasty is 1.5% and the incidence of femoral neck fracture is 0.67%. Across all studies, 2 cases of osteonecrosis were reported. Four studies reported improvement in Harris hip scores. However, only 1 study reported a statistically significant improvement. Three studies reported improvement in SF-12 scores, of which 2 reported a significant improvement. One study reported significant improvement in UCLA hip score. Two studies reported postoperative Oxford hip scores, but no preoperative values were reported. None of the reviewed studies r

2006-01-01

7

Serum metal ion levels after second-generation metal-on-metal total hip arthroplasty  

Microsoft Academic Search

Introduction  Metal-on-metal bearings for total hip arthroplasty are increasing in popularity. However, metal ion toxicity, metal hypersensitivity,\\u000a and metal carcinogenicity are the causes concern for patients with metal-on-metal hip replacement. We investigated serum levels\\u000a of cobalt and chromium ions in patients with successfully implanted second-generation metal-on-metal total hip arthroplasty\\u000a (THA) using PINNACLE-A (DePuy, Warsaw, IN, USA).\\u000a \\u000a \\u000a \\u000a \\u000a Materials and methods  Thirty-three patients underwent

Takao Imanishi; Masahiro Hasegawa; Akihiro Sudo

2010-01-01

8

Failure of a metal-on-metal total hip arthroplasty from progressive osteolysis  

Microsoft Academic Search

Ultra-high-molecular weight polyethylene (UHMWPE) wear, debris-induced osteolysis is a frequent cause of failure of total hip arthroplasty. Metal-on-metal total hip arthroplasty eliminates the generation of UHMWPE particulate debris. Although the volumetric wear of a metal-on-metal articulation may be lower than a metal-UHMWPE articulation, the number of particles may be higher. Osteolysis can develop in response to metallic and UHMWPE debris.

Catherine Klapperich; Jove Graham; Lisa Pruitt; Michael D. Ries

1999-01-01

9

Large-diameter metal-on-metal total hip arthroplasties: A page in orthopedic history?  

PubMed

Large-diameter metal-on-metal (MoM) bearings evolved from the success of hip resurfacing. These implants were used in revision surgery in cases with well-fixed acetabular cups but loose or failed femoral stems, to avoid cup revision. Early data showed low rates of dislocation and potentially low wear profiles due to better fluid film lubrication. The risk of impingement was also thought to be low due to the increased head-neck ratio. Subsequently large-diameter MoM heads gained popularity in primary hip replacement. Recent data has emerged on the unacceptably high revision rates among patients with large-diameter MoM total hip arthroplasties (THAs), high blood levels of metal ions, and adverse tissue reactions. The head-neck (cone-taper) modular interface probably represents the weak link in large metal heads that have been used on conventional tapers. Increased torque of the large head, micromotion, and instability at the cone-taper interface, synergistic interactions between corrosion and wear, edge loading, low clearance, and psoas impingement are the likely causes for early failure of these prostheses. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3320-3326, 2013. PMID:23529961

Singh, Gurpal; Meyer, Heiko; Ruetschi, Marcel; Chamaon, Kathrin; Feuerstein, Bernd; Lohmann, Christoph H

2013-03-25

10

5B.1 Metallosis in Metal-on-Metal PPF Total Hip Arthroplasties  

Microsoft Academic Search

Metallosis in total hip arthroplasty (THA) is a not commonly reported complication. We followed 173 consecutive patients, who had received primary, single and non-cemented proximal press fit (PFF) THA with metal-on-metal bearings made of low carbon content in 1995. Follow-up results are available for a total of 161 (93.1%) patients. The mean age of the patients was 63.3 years (31

R. Legenstein; W. Huber; P. Boesch

11

Metal-on-metal versus metal-on-polyethylene bearings in total hip arthroplasty  

Microsoft Academic Search

This case-control study was performed to investigate the hypothesis that metal-on-metal (M-M) bearings reduce the risk of aseptic component loosening when compared with metal-on-polyethylene (M-PE) bearings. Cases were identified from a computerized joint database as patients who had received a primary total hip arthroplasty using an M-M or M-PE bearing and had documented revision or radiographic loosening of the stem

Douglas Naudie; Christopher P. Roeder; Javad Parvizi; Daniel J. Berry; Stefan Eggli; Andre Busato

2004-01-01

12

Delayed hypersensitivity reaction caused by metal-on-metal total disc replacement.  

PubMed

The authors report the case of a 53-year-old woman who underwent placement of a metal-on-metal total disc replacement (TDR) device for the treatment of discogenic back pain. The initial postoperative course was normal, but 2 months after surgery she started to complain of a recurrence of pain and she progressively developed cauda equina syndrome. Radiological and biological findings showed an inflammatory polyneuropathy associated with an epidural mass. A diagnosis of cell-mediated hypersensitivity reaction (Type IV) was made after patch testing showed positive reactions for 1% cobalt chloride and chromium. A decision was made to remove the TDR device and to perform a circumferential fusion. This report is intended to inform the reader that systemic metal release and hypersensitivity reaction are possible complications of metal-on-metal TDR. PMID:23829286

Zairi, Fahed; Remacle, Jean Michel; Allaoui, Mohamed; Assaker, Richard

2013-07-05

13

No clinical difference between large metal-on-metal total hip arthroplasty and 28-mm-head total hip arthroplasty?  

Microsoft Academic Search

Purpose  We aimed to test the claim of greater range of motion (ROM) with large femoral head metal-on-metal total hip arthroplasty.\\u000a \\u000a \\u000a \\u000a Methods  We compared 28-mm metal-on-polyethylene (MP) total hip arthroplasty with large femoral head metal-on-metal (MM) total hip\\u000a arthroplasty in a randomised clinical trial. ROM one year postoperatively was determined in 50 patients. Mean head sizes were\\u000a 28 mm (MP) and 48 mm (MM).

Wierd P. Zijlstra; Inge van den Akker-Scheek; Mark J. M. Zee; Jos J. A. M. van Raay

14

Metal-on-metal bearings total hip arthroplasty: the cobalt and chromium ions release concern.  

PubMed

With certain concerns recently reported on metal-on-metal bearing couples in total hip arthroplasty, this study's objective is to review the current knowledge concerning release of metal ions and its potential consequences. Each metal-on-metal implant presents different tribological properties. The analytical techniques for metals are accurate and the Co ion rates seem acceptable up to 2 ?g/L. A delayed type IV hypersensitivity reaction (atypical lymphocytic vasculitis-associated lesion [ALVAL]) may be the source of arthroplasty failure. Idiosyncratic, it remains unpredictable even using cutaneous tests and apparently is rare (0.3%). Today, there are no scientific or epidemiologic data supporting a risk of carcinogenesis or teratogenesis related to the use of a metal-on-metal bearings couple. Solid pseudotumors nearly exclusively are observed with resurfacing procedures, carrying a high annual revision rate in women under 40 years of age, occurring particularly in cases of acetabular malposition and with use of cast molded Cr-Co alloys. Osteolysis manifests through complete and progressive radiolucent lines or through cavitary lesions stemming from ALVAL-type alterations or impingement problems or implant incompatibility. The formation of wear debris exceeding the biological tolerance is possible with implant malposition, subluxation, and jamming of the femoral head in cases of cup deformity. Moreover, each implant presents different metal ion production; assessment of their performance and safety is required before their clinical use. With the knowledge available today, metal-on-metal bearing couples are contraindicated in cases of metal allergies or end stage renal dysfunction and small size resurfacing should cautiously be used. PMID:20832379

Delaunay, C; Petit, I; Learmonth, I D; Oger, P; Vendittoli, P A

2010-09-15

15

Cementless Metasul metal-on-metal total hip arthroplasties at 13 years.  

PubMed

Second-generation metal-on-metal bearings have been used since the late 1980s as alternative bearings to eliminate aseptic loosening due to polyethylene wear. The aim of the present study was to evaluate the long-term results of a series of Metasul (Zimmer GmbH, Winterthur, Switzerland) metal-on-metal total hip arthroplasty (THA). One hundred forty-nine cementless THAs with a 28-mm Metasul articulation were performed in 111 consecutive patients. The results were retrospectively reviewed at 13 years postoperatively. Clinical and radiographic evaluations and implant survivorship were performed. Seven hips (4.7%) were revised. The overall survivorship with revision for any reason as the end point was 0.94. The average Harris hip score was 91.4. Expansive osteolysis was found adjacent to the stem in 4 hips. Metal wear-related aseptic loosening was not the major reason for failure in our Metasul metal-on-metal THAs. Recurrent dislocation was the main reason for revision in our series. PMID:21621954

Randelli, Filippo; Banci, Lorenzo; D'Anna, Alessandro; Visentin, Ornella; Randelli, Gianni

2011-05-31

16

Short-term results with the Zweymueller-SL metal-on-metal total hip arthroplasty  

Microsoft Academic Search

. In a prospective study we followed 266 consecutive patients who received 350 Zweymueller-SL uncemented total hip replacements with metal-on-metal articulation for osteoarthritis. Mean follow-up was 52 (range 37-92) months. Patient age at the time of surgery was 55±9 (25-70) years. Pre-operative Harris score of 45±19 was increased post-operatively to 96±4. Pre-operative invalidity was significantly improved post-operatively (P Résumé. étude

Panagiotis Korovessis; Georgios Petsinis; Maria Repanti; Zisis Papazisis; Panagiotis Iliopoulos; Panagiotis N. Soucacos

2002-01-01

17

Systemic metal exposure in large- and small-diameter metal-on-metal total hip replacements.  

PubMed

Large-diameter metal-metal total hip replacement (THR) offers the advantages of low wear and low dislocation risk. the aim of this investigation was to compare metal levels in large and small-diameter metal-metal hip replacements. Whole blood concentrations and daily output of cobalt and chromium in 28 patients with unilateral large diameter (42- to 54-mm) metal on metal hip replacements at 1-year follow-up were compared with levels in patients with 28-mm metal-on-metal THRs. Both bearings were made of high-carbon cobalt-chrome alloy. The larger bearing is as-cast and the smaller wrought alloy. High-resolution inductively coupled plasma mass spectrometry was used for analysis. The patients had either a cemented polished tapered stainless steel stem or a cementless porous ingrowth titanium alloy stem. Mean whole blood levels in the small- and large-diameter THRs are not significantly different at 1 year (cobalt, 1.7 vs 2.3 microg/L and chromium 1.7 vs 1.4 microg/L). Daily urinary output of cobalt and chromium was also in the same range and without a significant mean difference (cobalt 11.6 microg/24 h in large-diameter and 12.3 microg/24 h in small-diameter THRs and chromium 3.7 and 4.1 microg/24 h, respectively). PMID:19298017

Daniel, Joseph; Ziaee, Hena; Pradhan, Chandra; McMinn, Derek J W

2008-12-01

18

Metal on metal hip resurfacing versus uncemented custom total hip replacement - early results  

PubMed Central

Introduction There is no current consensus on the most appropriate prosthesis for treating symptomatic osteoarthritis (OA) of the hip in young, active patients. Modern metal on metal hip resurfacing arthroplasty (HR) has gained popularity as it is theoretically more stable, bone conserving and easier to revise than total hip arthroplasty. Early results of metal on metal resurfacing have been encouraging. We have compared two well matched cohorts of patients with regard to function, pain relief and patient satisfaction. Methods This prospective study compares 2 cohorts of young, active patients treated with hip resurfacing (137 patients, 141 hips) and custom uncemented (CADCAM) stems (134 patients, 141 hips). All procedures were performed by a single surgeon. Outcome measures included Oxford, WOMAC and Harris hip scores as well as an activity score. Statistical analysis was performed using the unpaired student's t-test. Results One hundred and thirty four and 137 patients were included in the hip replacement and resurfacing groups respectively. The mean age of these patients was 54.6 years. The mean duration of follow up for the hip resurfacing group was 19.2 months compared to 13.4 months for the total hip replacement group. Pre operative oxford, Harris and WOMAC scores in the THA group were 41.1, 46.4 and 50.9 respectively while the post operative scores were 14.8, 95.8 and 5.0. In the HR group, pre- operative scores were 37.0, 54.1 and 45.9 respectively compared to 15.0, 96.8 and 6.1 post operatively. The degree of improvement was similar in both groups. Conclusion There was no significant clinical difference between the patients treated with hip resurfacing and total hip arthroplasty in the short term.

2010-01-01

19

[Are the concerns regarding metal-on-metal total hip arthroplasties founded in 2012?].  

PubMed

Metal-on-metal total hip arthroplasty (MOM THA) fuels debate in the orthopedic community after statistics showed higher-than-expected short-term failures in comparison with metal-on-polyethylene THA. The problem of early failure in the young, active patient with a metal-on-polyethylene implant has prompted the research of another couple. Multiple studies showed the advantages of MOM THA. The results of MOM resurfacing and MOM THA in our hospital did not show concerning results. Nonetheless, the data in the literature shows divergent opinions. The most recent statistics indicate that the results are disappointing, particularly with specific types of implants. Several institutions, in the USA and in Europe, are developing protocols for the follow-up of patients with MOM hip implants. Today, we are headed towards imposing a moratorium on using MOM THA. PMID:23444826

Valcu, C A; Perdreau, A; Wouters, A; Gillet, Ph

2013-01-01

20

The Prevalence of Groin Pain After Metal-on-Metal Total Hip Arthroplasty and Total Hip Resurfacing  

Microsoft Academic Search

Background  Groin pain after total hip arthroplasty (THA) or total hip resurfacing arthroplasty can be troubling for patients and surgeons.\\u000a Potential sources of pain include infection, loosening, metal hypersensitivity, or impingement of bony structures or the iliopsoas\\u000a tendon.\\u000a \\u000a \\u000a \\u000a \\u000a Questions\\/purposes  We compared the rate of groin pain after THA or hip resurfacing using metal-on-metal to those of other bearing surfaces.\\u000a \\u000a \\u000a \\u000a Methods  We identified 347

Robert B. Bartelt; Brandon J. Yuan; Robert T. Trousdale; Rafael J. Sierra

2010-01-01

21

Poor short term outcome with a metal-on-metal total hip arthroplasty.  

PubMed

Metal-on-metal (MoM) bearings for total hip arthroplasty (THA) have come under scrutiny with reports of high failure rates. Clinical outcome studies with several commercially available MoM THA bearings remain unreported. We evaluated 78 consecutive MoM THAs from a single manufacturer in 68 patients. Sixty-six received cobalt-chrome (CoCr) monoblock and 12 received modular titanium acetabular cups with internal CoCr liners. Femoral components were titanium with modular necks. At average 2.1 years postoperatively, 12 THAs (15.4%) demonstrated aseptic failure (10 revisions, 2 revision recommended). All revised hips demonstrated capsular necrosis with positive histology reaction for aseptic lymphocytic vasculitis-associated lesions/adverse local tissue reactions. Prosthetic instability following revision surgery was relatively common. Female gender was a strong risk factor for failure, though smaller cups were not. Both monoblock and modular components fared poorly. Corrosion was frequently observed around the proximal and distal end of the modular femoral necks. PMID:23538122

Levy, Yadin D; Ezzet, Kace A

2013-03-26

22

Metallosis, psoas abscess and infected hip prosthesis in a patient with bilateral metal on metal total hip replacement  

PubMed Central

Metal on metal hip (MoM) resurfacing / replacement has recently been one of the most discussed topics in orthopaedics. Significant revision rates and complications are associated with MoM. We report a patient presenting with infection of a total hip prosthesis in conjunction with a psoas abscess in which the presentation is complicated by radiological evidence of suspected metallic debris in the lower limb tissues and elevated chromium and cobalt levels, suggestive of metallosis secondary to MoM.

Rymaruk, S; Razak, A; McGivney, R

2012-01-01

23

Understanding the differences between the wear of metal-on-metal and ceramic-on-metal total hip replacements.  

PubMed

Hip simulator studies have been carried out extensively to understand and test artificial hip implants in vitro as an efficient alternative to obtaining long-term results in vivo. Recent studies have shown that a ceramic-on-metal material combination lowers the wear by up to 100 times in comparison with a typical metal-on-metal design. The reason for this reduction remains unclear and for this reason this study has undertaken simple tribometer tests to understand the fundamental material loss mechanisms in two material combinations: metal-on-metal and ceramic-on-ceramic. A simple-configuration reciprocating pin-on-plate wear study was performed under open-circuit potential (OCP) and with applied cathodic protection (CP) in a serum solution using two tribological couples: firstly, cobalt-chromium (Co-Cr) pins against Co-Cr plates; secondly, Co-Cr pins against alumina (Al2O3) plates. The pin and plate surfaces prior to and after testing were examined by profilometry and scanning electron microscopy. The results showed a marked reduction in wear when CP was applied, indicating that total material degradation under the OCP condition was attributed to corrosion processes. The substitution of the Co-Cr pin with an Al2O3 plate also resulted in a dramatic reduction in wear, probably due to the reduction in the corrosion-wear interactions between the tribological pair. PMID:18491698

Figueiredo-Pina, C G; Yan, Y; Neville, A; Fisher, J

2008-04-01

24

Do Large Heads Enhance Stability and Restore Native Anatomy in Primary Total Hip Arthroplasty?  

Microsoft Academic Search

Background  Dislocation remains a serious complication in hip arthroplasty. Resurfacing proponents tout anatomic femoral head restoration\\u000a as an advantage over total hip arthroplasty. However, advances in bearings have expanded prosthetic head options from traditional\\u000a sizes of 22, 26, 28, and 32 mm to diameters as large as 60 mm. Large heads reportedly enhance stability owing to increased\\u000a range of motion before impingement and

Adolph V. Lombardi Jr; Michael D. Skeels; Keith R. Berend; Joanne B. Adams; Orlando J. Franchi

2011-01-01

25

Controversies in Large Metal-on-Metal Cementless Total Hip Arthroplasty  

Microsoft Academic Search

Over the last several years, many orthopaedic surgeons have embraced so-called alternative bearing surfaces in total hip arthroplasty, largely on the basis of the hypothesis that a reduction in the volumetric wear rates afforded by these improved articulating couples will reduce the prevalence of osteolysis and aseptic loosening, which in turn will improve implant survivorship. We conducted the study on

P. Botez; C. I. Stoica; P. D. Sirbu; R. Asaftei; C. Grierosu

2010-01-01

26

Metal-on-metal bearings in cementless primary total hip arthroplasty  

Microsoft Academic Search

One hundred cementless titanium primary total hip arthroplasties with 28 mm Metasul bearings were prospectively studied (osteoarthritis in 76% of hips, mean age 59.6 years). Ninety-eight were reviewed after a 6-year average follow-up (range, 17–126 months) with clinical results graded excellent and good in 97%. One femoral component was revised for aseptic loosening at 7.8 years. Postoperative cobalt level was

Christian P. Delaunay

2004-01-01

27

Wear particles from metal-on-metal total hip replacements: effects of implant design and implantation time.  

PubMed

Detailed characterization of wear particles is necessary to understand better the implant wear mechanisms and the periprosthetic tissue response. The purposes of the present study were to compare particle characteristics of current with older designs of metal-on-metal (MM) total hip replacements (THRs), and to determine the effect of implantation time on wear particle characteristics. Metal wear particles isolated from periprosthetic tissues from 19 patients with MM THRs of current and older designs and at different implantation times (very short, longer, and very long) were studied using transmission electron microscopy and energy dispersive X-ray analysis. The particles from the current design implants with implantation times of not more than 15 months (very short-term) were almost exclusively round to oval chromium oxide particles. In all other cases, although the predominance was still round to oval chromium oxide particles, greater proportions of cobalt-chromium-molybdenum (Co-Cr-Mo) particles, mainly needle-shaped, were detected. Very long-term THRs implanted for more than 20 years had the highest percentage of needle-shaped Co-Cr-Mo particles. Particle lengths were not markedly different between the different designs and implantation times except for the current design implants of not more than 15 months, which had a significantly smaller mean length of 39 nm. In conclusion, the implant design did not seem to have a significant influence on particle characteristics whereas the implantation time appeared to have the most effect on the particles. It should be noted that, because of the limited number of tissue retrievals available, some uncertainty remains regarding the generality of these findings. PMID:16669387

Catelas, I; Campbell, P A; Bobyn, J D; Medley, J B; Huk, O L

2006-02-01

28

Can we trust studies published by authors with financial conflicts? Using the decline of metal-on-metal total hip arthroplasty to investigate.  

PubMed

The objective of our study was to determine if authors with conflicts of interest are less likely to report negative study outcomes in metal-on-metal total hip arthroplasty. We performed a systematic review of 3 major orthopedic journals for articles related to metal-on-metal total hip arthroplasty over 12 years. A total of 64 studies reported clinical outcomes and were included. Reviewers assigned a positive, neutral, or negative label. Each study was noted for the presence of absence of a financial conflict. There was a significant trend from positive to negative study outcomes over time (P = .015). A similar negative trend was seen in studies written by authors with financial disclosures (P = .021). Authors with financial conflicts have contributed to the increase in negative outcomes reported in the literature. PMID:22682042

Hsu, Jason E; Liu, Stephen Y; Lee, Gwo-Chin

2012-06-06

29

Metal-on-metal hip resurfacing compared with 28-mm diameter metal-on-metal total hip replacement: A randomised study with six to nine years' follow-up.  

PubMed

A total of 219 hips in 192 patients aged between 18 and 65 years were randomised to 28-mm metal-on-metal uncemented total hip replacements (THRs, 107 hips) or hybrid hip resurfacing (HR, 112 hips). At a mean follow-up of eight years (6.6 to 9.3) there was no significant difference between the THR and HR groups regarding rate of revision (4.0% (4 of 99) vs 5.8% (6 of 104), p = 0.569) or re-operation rates without revision (5.1% (5 of 99) vs 2.9% (3 of 104), p = 0.428). In the THR group one recurrent dislocation, two late deep infections and one peri-prosthetic fracture required revision, whereas in the HR group five patients underwent revision for femoral head loosening and one for adverse reaction to metal debris. The mean University of California, Los Angeles activity scores were significantly higher in HR (7.5 (sd 1.7) vs 6.9 (sd 1.7), p = 0.035), but similar mean Western Ontario and McMaster Universities Osteoarthritis Index scores were obtained (5.8 (sd 9.5) in HR vs 5.1 (sd 8.9) in THR, p = 0.615) at the last follow-up. Osteolysis was found in 30 of 81 THR patients (37.4%), mostly in the proximal femur, compared with two of 83 HR patients (2.4%) (p < 0.001). At five years the mean metal ion levels were < 2.5 ?g/l for cobalt and chromium in both groups; only titanium was significantly higher in the HR group (p = 0.001). Although revision rates and functional scores were similar in both groups at mid-term, long-term survival analysis is necessary to determine whether one procedure is more advantageous than the other. Cite this article: Bone Joint J 2013;95-B:1464-73. PMID:24151264

Vendittoli, P-A; Rivière, C; Roy, A G; Barry, J; Lusignan, D; Lavigne, M

2013-11-01

30

Evaluation of the wear properties of a metal-on-metal total joint replacement system and in vitro macrophage response to resultant wear particles  

NASA Astrophysics Data System (ADS)

The wear of the polyethylene in total joint prostheses has been a source of morbidity and early device failure which has been extensively reported in the last ten to twelve years. While research continues to attempt to reduce the wear of polyethylene joint bearing surfaces by modifications in polymer processing, there is a renewed interest in the use of metal-on-metal bearing couples for hip replacement devices. This study investigated the in vitro wear resistance of two cobalt/chromium/molybdenum alloys, which differed primarily in the carbon content, as potential alloys for use in such a metal-on-metal hip bearing couple. The results showed that the alloy with the higher (0.25%) carbon content was more wear resistant and this alloy was chosen for testing in a hip simulator system which modeled the loads and motions which might be exerted on a clinically implanted hip replacement. Comparison of the results of metal-on-polyethylene specimens to metal-on-metal specimens showed that the volumetric wear of the metal-on-polyethylene bearing couple over 5,000,000 cycles was 110--180 times as great as that for the metal bearing couple. Polyethylene and metal particles retrieved from either pin-on-disk testing lubricant or hip simulator testing lubricant were cleaned and examined for consistency with the particles reported by other laboratories for particles from periprosthetic tissues and found to be similar. The particles were then added to macrophage (J774a) cell cultures and the release of Prostaglandin E2, Interleukin-6, and Tumor Necrosis Factor alpha measured for each experiment in response to the particles. The cell mediators released by the cells was found to correlate with the dosage of particles and the chemical identity of the particles. Most of the cellular response to the polyethylene particles seemed to be as a result of phagocytosis of the particles while most of the response to metal particles seemed to be related to cytotoxicity of the particles. Based upon the results of this study, metal-on-metal hip prostheses prepared from the high carbon cobalt/chromium alloy (CCM+) that was investigated seem to hold sufficient promise to justify human clinical trials.

St. John, Kenneth Raymond

31

Few Adverse Reactions to Metal on Metal Articulation in Total Hip Arthroplasty in a Review Study on 358 Consecutive Cases with 1 to 5 Years Follow-Up  

PubMed Central

The aim of the present study was to determine the frequency of adverse reaction to metal on metal total hip arthroplasty using a M2a-38 articulation and a Magnum articulation, (Biomet Warsaw, Indiana). All patients who had received a Metal on Metal bearing prosthesis, in two centres in Copenhagen, were asked to complete a questionnaire about groin pain. Patients with self-reported groin pain, 68/314, underwent a physical examination and had Co and Cr ion levels measured in full blood samples. Fifty patients also had a CT scan performed. The present study found one patient with bilateral arthroplasty, who had an adverse reaction on one side. In addition the study showed that females had higher values of Co and Cr, and that younger patient reported groin pain more often. The conclusion of this study is that the number of adverse reactions is low, despite the time of observation being relatively short, no high frequency of adverse reactions to this prosthesis is expected.

Sturup, Jens; Dahl, Line B; Jensen, Karl-Erik; Larsen, Anne-Birgitte; Gebuhr, Peter

2012-01-01

32

Failure of Larger-Diameter Metal-on-Metal Total Hip Arthroplasty Resulting from Anterior Iliopsoas Impingement  

Microsoft Academic Search

Anterior iliopsoas impingement is a recognized cause of persistent groin pain after total hip arthroplasty. We report 3 patients with failed total hip arthroplasties resulting from anterior iliopsoas and capsular impingement secondary to a metal femoral ball with a diameter larger than the native femoral head. All patients had the same implant design. Resolution of symptoms occurred in all patients

James A. Browne; David J. Polga; Rafael J. Sierra; Robert T. Trousdale; Miguel E. Cabanela

2011-01-01

33

The Latest Lessons Learned from Retrieval Analyses of Ultra-High Molecular Weight Polyethylene, Metal-on-Metal, and Alternative Bearing Total Disc Replacements  

PubMed Central

Knowledge regarding the in vivo performance and periposthetic tissue response of cervical and lumbar total disc replacements (TDRs) continues to expand. This review addresses the following four main questions: 1) What are the latest lessons learned from polyethylene in large joints and how are they relevant to current TDRs? 2) What are the latest lessons learned regarding adverse local tissue reactions from metal-on-metal, CoCr bearings in large joints and how are they relevant to current TDRs? 3) What advancements have been made in understanding the in vivo performance of alternative biomaterials, such as stainless steel and polycarbonate urethane, for TDRs in the past five years? 4) How has retrieval analysis of all these various artificial disc bearing technologies advanced the state of the art in preclinical testing of TDRs? The study of explanted artificial discs and their associated tissues can help inform bearing selection as well as the design of future generations of disc arthroplasty. Analyzing retrieved artificial discs is also essential for validating preclinical test methods.

Kurtz, Steven M.; Toth, Jeffrey M.; Siskey, Ryan; Ciccarelli, Lauren; MacDonald, Dan; Isaza, Jorge; Lanman, Todd; Punt, Ilona; Steinbeck, Marla; Goffin, Jan; van Ooij, Andre

2012-01-01

34

In vitro analysis of the wear, wear debris and biological activity of surface-engineered coatings for use in metal-on-metal total hip replacements.  

PubMed

Extremely low wear rates have been reported for metal-on-metal total hip replacements, but concerns remain about the effects of metal ion release, dissolution rates and toxicity. Surface-engineered coatings have the potential to improve wear resistance and reduce the biological activity of the wear debris produced. The aim of this study was to examine the wear and wear debris generation from surface-engineered coatings: titanium nitride (TiN), chromium nitride (CrN) and chromium carbon nitride (CrCN) applied to a cobalt-chrome alloy (CoCr) substrate. The coatings were articulated against themselves in a simple geometry model. The wear particles generated were characterized and the cytotoxic effect on U937 macrophages and L929 fibroblasts assessed. The CrN and CrCN coatings showed a decrease in wear compared to the CoCr bearings and produced small (less than 40 nm in length) wear particles. The wear particles released from the surface engineered bearings also showed a decreased cytotoxic effect on cells compared to the CoCr alloy debris. The reduced wear volumes coupled with the reduced cytotoxicity per unit volume of wear indicate the potential for the clinical application of this technology. PMID:12807156

Williams, S; Tipper, J L; Ingham, E; Stone, M H; Fisher, J

2003-01-01

35

Clinical outcome study and radiological findings of Zweymuller metal on metal total hip arthroplasty. a follow-up of 6 to 15 years.  

PubMed

We report the clinical and radiological outcome of 99 Zweymuller metal on metal total hip arthroplasties in 84 patients followed up prospectively for a mean period of 9.5 (range, 6-15) years. There were 29 (34.5%) male and 55 (65.5%) female patients with a mean age of 62.85 years (range, 50-70 years) at the time of surgery. All patients had osteoarthritis. One acetabular component and one stem were revised due to aseptic loosening. One femoral stem was revised due to a periprosthetic fracture. HHS score improved from a preoperative mean of 62.56 points (SD 8.87) to a final postoperative follow-up mean of 93.48 (SD 7.7). Cumulative success rate for both implants at 13 years, with aseptic loosening as the end point, was 97.05%, while for both implants at 13 years, with revision for any reason as the end point, it was 91.17%. Satisfactory results were observed with the use of this prosthesis. PMID:20041375

Paleochorlidis, Ilias S; Badras, Leonidas S; Skretas, Efstathios F; Georgaklis, Vasilios A; Karachalios, Theofilos S; Malizos, Konstantinos N

36

Does Choice of Head Size and Neck Geometry Affect Stem Migration in Modular Large-Diameter Metal-on-Metal Total Hip Arthroplasty? A Preliminary Analysis  

PubMed Central

Due to their theoretical advantages, hip systems combining modular necks and large diameter femoral heads have gradually gained popularity. However, among others, concerns regarding changes in the load transfer patterns were raised. Recent stress analyses have indeed shown that the use of modular necks and big femoral heads causes significant changes in the strain distribution along the femur. Our original hypothesis was that these changes may affect early distal migration of a modular stem. We examined the effect of head diameter and neck geometry on migration at two years of follow-up in a case series of 116 patients (125 hips), who have undergone primary Metal-on-Metal total hip arthroplasty with the modular grit-blasted Profemur®E stem combined with large-diameter heads (>36 mm). We found that choice of neck geometry and head diameter has no effect on stem migration. A multivariate regression analysis including the potential confounding variables of the body mass index, bone quality, canal fill and stem positioning revealed only a negative correlation between subsidence and canal fill in midstem area. Statistical analysis, despite its limitations, did not confirm our hypothesis that choice of neck geometry and/or head diameter affects early distal migration of a modular stem. However, the importance of correct stem sizing was revealed.

Georgiou, CS; Evangelou, KG; Theodorou, EG; Provatidis, CG; Megas, PD

2012-01-01

37

Elevated Serum Cobalt With Metal-on-metal Articulating Surfaces  

Microsoft Academic Search

We determined serum cobalt levels in 55 patients by atomic absorption spectrophotometry before and after implantation of uncemented total hip arthroplasties. In a randomised, prospective trial 27 wrought Co-28Cr-6Mo-0.2C metal-on-metal articulations were compared with 28 ceramic-on-polyethylene hips which did not contain cobalt. Other sources of iatrogenic cobalt loading were excluded. The metal-on-metal group produced detectable serum cobalt levels (median 1.1

Wolfram Brodner; Peter Bitzan; Vanee Meisinger; Alexandra Kaider; Florian Gottsauner-Wolf; R. Kotz

1997-01-01

38

Effect of femoral head size on the wear of metal on metal bearings in total hip replacements under adverse edge-loading conditions  

PubMed Central

Abstract Metal-on-metal (MoM) bearings have shown low-wear rates under standard hip simulator conditions; however, retrieval studies have shown large variations in wear rates and mechanisms. High-wear in vivo has caused catastrophic complications and has been associated with steep cup-inclination angle (rotational malpositioning). However, increasing the cup-inclination angle in vitro has not replicated the increases in wear to the same extent as those observed in retrievals. Clinically relevant wear rates, patterns, and particles were observed in vitro for ceramic-on-ceramic bearings when microseparation (translational malpositioning) conditions were introduced into the gait cycle. In the present study, 28 and 36-mm MoM bearings were investigated under adverse conditions. Increasing the cup angle from 45° to 65° resulted in a significant increase in the wear rate of the 28 mm bearings. However, for the 36 mm bearings, head-rim contact did not occur under the steep cup-angle condition, and the wear rate did not increase. The introduction of microseparation to the gait cycle significantly increased the wear rate of the MoM bearings. Cup angle and head size did not influence the wear rate under microseparation conditions. This study indicated that high-in vivo wear rates were associated with edge loading due to rotational malpositioning such as high-cup-inclination angle and translational malpositioning that could occur due to several surgical factors. Translational malpositioning had a more dominant effect on the wear rate. Preclinical simulation testing should be undertaken with translational and rotational malpositioning conditions as well as standard walking cycle conditions defined by the ISO standard. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.

Al-Hajjar, Mazen; Fisher, John; Williams, Sophie; Tipper, Joanne L; Jennings, Louise M

2013-01-01

39

Metal-on-Metal Hip Retrieval Analysis: A Case Report  

PubMed Central

This is a case report involving a single case with severe bone and soft tissue destruction in a young male patient with a 10-year-metal on-metal total hip arthroplasty. Following complete aseptic erosion of the affected hip greater trochanter and abductor muscles, the hip was revised for recurrent instability. Histological examination of the patient's periprosthetic tissues, serological studies, and review of recent medical reports of similar cases were used to support an explanation of the destructive process and better contribute to our understanding of human reaction to metal debris in some patients following metal-on-metal hip arthroplasty.

Pace, Thomas B.; Rusaw, Kara A.; Minette, Lawrence J.; Shirley, Brayton R.; Snider, Rebecca G.; DesJardins, John D.

2013-01-01

40

Metal-on-Metal Hip Retrieval Analysis: A Case Report.  

PubMed

This is a case report involving a single case with severe bone and soft tissue destruction in a young male patient with a 10-year-metal on-metal total hip arthroplasty. Following complete aseptic erosion of the affected hip greater trochanter and abductor muscles, the hip was revised for recurrent instability. Histological examination of the patient's periprosthetic tissues, serological studies, and review of recent medical reports of similar cases were used to support an explanation of the destructive process and better contribute to our understanding of human reaction to metal debris in some patients following metal-on-metal hip arthroplasty. PMID:23840999

Pace, Thomas B; Rusaw, Kara A; Minette, Lawrence J; Shirley, Brayton R; Snider, Rebecca G; Desjardins, John D

2013-06-09

41

Squeaking in Metal-on-Metal Hip Resurfacing Arthroplasties  

Microsoft Academic Search

Background  While most reports of audible squeaking in total hip arthroplasty (THA) have focused on ceramic bearings, squeaking can occur\\u000a in metal-on-metal bearings and may be an important clinical complication to consider during patient followup.\\u000a \\u000a \\u000a \\u000a \\u000a Questions\\/purposes  We retrospectively identified 10 patients with squeaking metal-on-metal hip resurfacings.\\u000a \\u000a \\u000a \\u000a Methods  This study reports acetabular inclination angles and patient satisfaction, and describes two patients with squeaking resurfacings:

Christina Esposito; William L. Walter; Pat Campbell; Anne Roques

2010-01-01

42

Abductor dysfunction and related sciatic nerve palsy, a new complication of metal-on-metal arthroplasty.  

PubMed

The optimal bearing for use in young patients with hip arthritis remains elusive. Current options include metal-on-cross-linked polyethylene, ceramic-on-cross-linked polyethylene, ceramic on ceramic, and metal on metal. Each of these bearing couples has advantages and disadvantages. Metal-on-metal designs allow the use of large heads that decrease impingement and improve stability. This fact has made this bearing an attractive option for surgeons and patients alike. This case report will illustrate a severe adverse reaction to metal debris with necrosis of soft tissues and subsequent damage to the sciatic nerve. PMID:22226612

Beaver, Walter B; Fehring, Thomas K

2012-01-05

43

A retrospective comparative study of mortality and causes of death among patients with metal-on-metal and metal-on-polyethylene total hip prostheses in primary osteoarthritis after a long-term follow-up  

PubMed Central

Background All patients with total hip arthroplasty (THA), especially those with metal-on-metal (MM) THA, are exposed to metallic particles and ions, which may cause total or site-specific mortality. We analyzed the causes of total and site-specific mortality among a cohort of patients with MM and with metal-on-polyethylene (MP) THA after a long follow-up time. Methods Standardized mortality ratios (SMR) of total and site-specific causes of death were calculated for 579 patients with MM (McKee-Farrar) and 1585 patients with MP (Brunswik, Lubinus) THA for primary osteoarthritis. Results Mean follow-up time was 17.9 years for patients with MM and 16.7 years for patients with MP. Overall SMR was 0.95 for the MM cohort and 0.90 for the MP cohort, as compared to the normal population. Both cohorts showed significantly decreased mortality for the first decade postoperatively, equal mortality over the next 10 years, and significantly increased mortality after 20 years. Patients with MM THA had higher cancer mortality (SMR 1.01) than those with MP THA (SMR 0.66) during the first 20 years postoperatively, but not thereafter. Conclusion Both MM and MP prostheses are safe based on total and site-specific mortality of recipients during the first 20 postoperative years in comparison with the general population.

2010-01-01

44

Metal-on-metal hip resurfacing: a critical review  

Microsoft Academic Search

In this article, a concise review of the current literature on metal-on-metal hip resurfacing (MoMHR) is given. In contrast\\u000a to conventional total hip arthroplasty, older age, female sex and small femoral head sizes predispose to failure. Neck fracture\\u000a and metal wear-related complications account for the most frequent reasons for re-operations. Although the long-term consequences\\u000a of metal ion release remain unknown,

Gavin J. Macpherson; Steffen J. Breusch

2011-01-01

45

Risk of cancer with metal-on-metal hip replacements: population based study  

PubMed Central

Objective To assess the risk of cancer associated with modern primary metal-on-metal hip replacements. Design Population based study. Setting Nationwide retrospective comparative register. Participants 10?728 patients who underwent metal-on-metal total hip arthroplasty and 18?235 patients who underwent conventional metal-on-polyethylene, ceramic-on-polyethylene, and ceramic-on-ceramic total hip arthroplasty (the non-metal-on-metal cohort) in the Finnish Arthroplasty Register 2001-10. Data on cancer cases up to 2010 for these cohorts were extracted from the Finnish Cancer Registry. Main outcome measures The relative risk of cancer was expressed as the ratio of observed to expected number of cases from the Finnish population—that is, the standardised incidence ratio. The relative risk of cancer in the metal-on-metal cohort compared with the non-metal-on-metal cohort was estimated with analyses of these ratios and Poisson regression. Results The overall risk of cancer in patients with metal-on-metal hip implants was similar to that in the Finnish population (378 observed v 400 expected, standardised incidence ratio 0.95, 95% confidence interval 0.85 to 1.04). The overall risk of cancer in patients with metal-on-metal hip implants was also no higher than in patients who had received non-metal-on-metal hip implants (relative risk 0.92, 0.81 to 1.05). Conclusions Metal-on-metal hip replacements are not associated with an increased overall risk of cancer during a mean follow-up of four years.

2012-01-01

46

Clinical manifestations in ten patients with asymptomatic metal-on-metal hip arthroplasty with very high cobalt levels.  

PubMed

Reports of adverse reactions to metal particle debris with metal-on-metal (MoM) hip arthroplasty have increased recently. Apart from the formation of pseudotumours and higher revision rates, another major cause for concern are the systemic effects of metal ions. Several effects of elevated systemic cobalt ions have been reported (e.g. myocardial and neurological effects, hypothyroidism). All 643 patients who underwent a stemmed large head MoM total hip replacement in our clinic were screened with repeated whole blood samples of metal ions (cobalt, chromium). We included ten asymptomatic unrevised patients with the highest cobalt concentrations, determined at a minimum of three years after implantation. These patients were subjected to an extensive neurological and cardiological screening protocol. In addition, blood samples were taken to assess renal and thyroid function. Ten patients with a cobalt level of 18-153 µg/L (mean 46.8 µg/L) were included. Nine patients were female, mean age was 65 years (range 56-75). The mean follow-up period was 4.2 years (range 3.0-6.1). Seven patients had bilateral stemmed MoM hip arthroplasty. No signs or symptoms of neurological dysfunction, cardiomyopathy, or renal or thyroid dysfunction could be identified or attributed to elevated cobalt levels. The clinical relevance of this study is that after short-term follow-up highly elevated blood cobalt levels do not cause systemic effects in our population. Hence in asymptomatic patients metal ions appear not to be a significant factor in the decision of when to revise a MoM large head total hip replacement. PMID:23813157

van Lingen, Christiaan P; Ettema, Harmen B; Timmer, Jorik R; de Jong, Gosse; Verheyen, Cees C P M

2013-06-28

47

THA Using Metal-on-Metal Articulation in Active Patients Younger Than 50 Years  

Microsoft Academic Search

The main concern of patients with longer life expectancies and of patients who are younger and more active is the longevity\\u000a of their total hip arthroplasty. We retrospectively reviewed 83 cementless total hip arthroplasties in 73 patients implanted\\u000a with metal-on-metal articulation. All patients were younger than 50 years old (average age, 41 years) at the time of the index\\u000a procedure, and 80%

Christian P. Delaunay; François Bonnomet; Philippe Clavert; Philippe Laffargue; Henri Migaud

2008-01-01

48

Metal-on-metal: history, state of the art (2010)  

PubMed Central

The history of metal-on-metal bearing began with K. Mc Kee. Several "episodes" have marked the history of metal-on-metal articulations, and each has contributed to a better understanding of this type of tribology. But to date the indications for this bearing are debated and are subject to reservations because of the existence of permanently elevated levels of circulating metal ions. It therefore appears that the monitoring of our patients, the documentation of our revisions and the collaboration with our industry partners as well as communicating with our biology and pathology colleagues is necessary to help us solve these problems.

2011-01-01

49

Short-term results of the M 2a-taper metal-on-metal articulation  

Microsoft Academic Search

A polyethylene-free, metal-on-metal acetabular system (M2a-taper [Biomet, Inc., Warsaw, IN]) was designed in an effort to improve total hip arthroplasty (THA) longevity. Minimum 2-year follow-up results involving 72 polyethylene liner THAs and 78 metal liner THAs from a multicenter, randomized, controlled, investigational device exemption study are reported. Mean Harris hip scores of 95.54 (polyethylene liner group) and 95.23 (metal liner

Adolph V. Lombardi; Thomas H. Mallory; Michael M. Alexiades; John M. Cuckler; Philip M. Faris; Kenneth A. Jaffe; E. Michael Keating; Carl L. Nelson; Chitranjan S. Ranawat; Joseph Williams; Richard Wixson; Jodi F. Hartman; Susan G. Capps; Cheryl A. Kefauver

2001-01-01

50

Taper junction failure in large-diameter metal-on-metal bearings  

PubMed Central

Objectives An ongoing prospective study to investigate failing metal-on-metal hip prostheses was commenced at our centre in 2008. We report on the results of the analysis of the first consecutive 126 failed mated total hip prostheses from a single manufacturer. Methods Analysis was carried out using highly accurate coordinate measuring to calculate volumetric and linear rates of the articular bearing surfaces and also the surfaces of the taper junctions. The relationship between taper wear rates and a number of variables, including bearing diameter and orientation of the acetabular component, was investigated. Results The measured rates of wear and distribution of material loss from the taper surfaces appeared to show that the primary factor leading to taper failure is the increased lever arm acting on this junction in contemporary large-diameter metal-on-metal hip replacements. Conclusions Our analysis suggests that varus stems, laterally engaging taper systems and larger head diameters all contribute to taper failure.

Langton, D. J.; Sidaginamale, R.; Lord, J. K.; Nargol, A. V. F.; Joyce, T. J.

2012-01-01

51

Engineering issues and wear performance of metal on metal hip implants.  

PubMed

A major concern in total hip arthroplasty is the generation of polyethylene wear particles at the articulating surfaces and resulting macrophage mediated periimplant osteolysis. There is renewed interest in metal on metal bearings as a solution to this problem in view of their potential for greatly improved wear performance. Using a commercially available hip simulator, the wear performance of metal on metal femoral head and acetabular cup combinations was evaluated and various parameters affecting metal on metal implant wear were identified. Nine implants custom manufactured from 2 medical grades of CoCrMo alloy (ASTM F1537-95 and F75-92) were tested within bovine serum as the lubricant to 3 million cycles (equivalent to approximately 3 years of service in vivo). The progressive wear of the components was determined by gravimetric methods at approximately every 300,000 cycles. The wear rates were characterized by an initial period of accelerated wear after which a lower steady state wear rate was observed for subsequent cycles. The presence of calcium phosphate films on the component surfaces, the microstructure of the lower carbon, wrought alloy, and increased effective radii (decreased diametral clearances) were identified as factors that may be favorable to improved wear performance. The extent of the effect on wear of each parameter, however, cannot be discerned at this point and necessitates a study in which parametric changes are more tightly controlled. The present study suggests that the use of metal on metal articulating surfaces may mitigate the problem of osteolysis by offering improved wear performance. PMID:8981885

Chan, F W; Bobyn, J D; Medley, J B; Krygier, J J; Yue, S; Tanzer, M

1996-12-01

52

The Otto Aufranc Award. Wear and lubrication of metal-on-metal hip implants.  

PubMed

The implication of polyethylene wear particles as the dominant cause of periprosthetic osteolysis has created a resurgence of interest in metal-on-metal implants for total hip arthroplasty because of their potential for improved wear performance. Twenty-two cobalt chromium molybdenum metal-on-metal implants were custom-manufactured and tested in a hip simulator. Accelerated wear occurred within the first million cycles followed by a marked decrease in wear rate to low steady-state values. The volumetric wear at 3 million cycles was very small, ranging from 0.15 to 2.56 mm3 for all implants tested. Larger head-cup clearance and increased surface roughness were associated with increased wear. Independent effects on wear of material processing (wrought, cast) and carbon content were not identified. Implant wear decreased with increasing lambda ratio, a parameter used to relate lubricant film thickness to surface roughness, suggesting some degree of fluid film lubrication during testing. This study provided important insight into the design and engineering parameters that affect the wear behavior of metal-on-metal hip implants and indicated that high quality manufacturing can reproducibly lead to very low wear. PMID:10611857

Chan, F W; Bobyn, J D; Medley, J B; Krygier, J J; Tanzer, M

1999-12-01

53

Metal-on-metal surface replacement: a triumph of hope over reason: opposes.  

PubMed

Hip resurfacing has been performed for over a decade but still raises controversy as an alternative to traditional total hip arthroplasty (THA). Concerns exist about the potential complications of hip resurfacing, including femoral neck fracture and osteonecrosis of the femoral head. Recently, attention has been given to the metal-on-metal bearing of hip resurfacing with regard to production of metal ions, possible tissue necrosis, and rare instances of metal hypersensitivity. Given the success of the gold-standard THA, it is understandable why some surgeons believe metal-on-metal surface replacement to be "a triumph of hope over reason." However, this article opposes that viewpoint, demonstrating that data exist to justify the practice of preserving bone in younger patients. Hip resurfacing can maintain femoral bone without the expense of removing additional acetabular bone by using modern implants with incremental sizing. Furthermore, many of the problems cited with the bearing couple (such as excess metal production) have been due to poor implant designs, which have now been removed from the market. Finally, we now realize that the metal-on-metal articulation is more sensitive to malposition; thus, good surgical technique and experience can solve many of the problems that have been cited in the past. National registry results confirm that in a select population, hip resurfacing performs comparably to THA, while fulfilling the goal of bone preservation. PMID:21902125

Su, Edwin P; Su, Sherwin L

2011-09-09

54

Metal-on-metal joint bearings and hematopoetic malignancy  

PubMed Central

Abstract This is a review of the hip arthroplasty era. We concentrate on new metal bearings, surface replacements, and the lessons not learned, and we highlight recent reports on malignancies and joint implants. A low incidence of blood malignancies has been found in bone marrow taken at prosthetic surgery. The incidence is increased after replacement with knee implants that release very low systemic levels of metal ions. A carcinogenic effect of the high levels of metal ions released by large metal-on-metal implants cannot be excluded. Ongoing Swedish implant registry studies going back to 1975 can serve as a basis for evaluation of this risk.

2012-01-01

55

Incidence of groin pain after metal-on-metal hip resurfacing.  

PubMed

Metal-on-metal hip resurfacing is offered as an alternative to traditional THA for the young and active adult with advanced osteoarthritis. However, patients undergoing hip resurfacing may be predisposed to persistent groin pain due to insufficient head/neck offset, an uncovered acetabular component, or both. We therefore determined the incidence of groin pain after metal-on-metal hip resurfacing, its impact on patient function, and possible risk factors contributing to groin pain. We evaluated 116 patients with a followup of at least 12 months after surgery (mean, 26 months; range, 12-61 months). The mean age was 48.8 years (range, 24.0-66.3 years), with 21 women (18%) and 95 men (82%). All patients were evaluated clinically and radiographically and had a Harris hip score, WOMAC, UCLA Activity Rating Scale, and the RAND-36 General Health measure; they were specifically asked if they experienced groin pain currently or since their surgery. Although all patients had functional improvements postoperatively, 21 of 116 of the patients (18%) reported groin pain; 12 of these (10% of the total) stated the pain limited their activities of daily living and 11 (10%) required medication for pain. Female patients were at greater risk of having groin pain. Of the patients with groin pain, three patients had muscle atrophy with a joint effusion on CT; one of these patients had revision surgery for the pain. Patients with metal-on-metal resurfacing may have a higher incidence of pain than those with conventional THA. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. PMID:19862587

Bin Nasser, Ahmad; Beaulé, Paul E; O'Neill, Michelle; Kim, Paul R; Fazekas, Anna

2010-02-01

56

Metal-on-Metal Bearings and Hypersensitivity in Patients with Artificial Hip Joints A CLINICAL AND H ISTOMORPHOLOGICAL S TUDY  

Microsoft Academic Search

Background: Some patients who have a total hip replacement with a second-generation metal-on-metal articulation have persistent or early recurrence of preoperative symptoms. Characteristic histological changes in the peripros- thetic tissues suggested the development of an immunological response. Therefore, in order to determine the rele- vance of these symptoms, we performed a study of the clinical data and periprosthetic tissues associated

HANS-GEORG WILLERT; GOTTFRIED H. BUCHHORN; AFSHIN FAYYAZI; RENATA FLURY; MARKUS WINDLER; GEORG KÖSTER; CHRISTOPH H. LOHMANN

57

A comparative joint simulator study of the wear of metal-on-metal and alternative material combinations in hip replacements.  

PubMed

While total hip replacement represents the major success story in orthopaedic surgery in the twentieth century, there is much interest in extending even further, early in the twenty first century, the life of implants. Osteolysis has been identified as a major factor limiting the life of prostheses, with indications that fine polyethylene wear debris, generated primarily at the interface between the femoral head and the acetabular cup, promotes the process. There is therefore considerable interest in the introduction of alternative wear resistant systems to limit the deleterious effects of wear. These alternatives include ceramic-on-ceramic and metal-on-metal configurations and the present paper is primarily concerned with the latter. Some six pairs of new metal-on-metal implants of 36 mm diameter and four pairs of existing metal-on-metal implants of 28 mm diameter were tested in a ten-station hip joint simulator in the presence of a 25 per cent bovine serum solution. The implants were tested in the anatomical position to 5 x 10(6) cycles. The new heads and cups were manufactured from CoCrMo alloy with careful attention being paid to sphericity and surface finish of both components. The wear performance of the new and existing metal-on-metal total hip replacements have been evaluated and compared. The overall wear rates have then been compared with previously reported wear rates for a zirconia-on-polyethylene prosthesis of 22 mm diameter tested on the same simulator. The comparison is taken further by recalling published penetration data for metal-on-polyethylene implants of 22 and 28 mm diameter and converting these to volumetric wear rates. It was found that the heads and cups in metal-on-metal joints wore by almost equal amounts and that the opposing surfaces converged to similar surface roughness as the testing time increased. Steady state wear rates were generally achieved after 1-2 x 10(6) cycles. The mean long-term wear rates for the metal-on-metal prostheses were very low, being 0.36 mm3/10(6) cycles and 0.45 mm3/10(6) cycles for the new implants of 36 mm diameter and established implants of 28 mm diameter respectively. These wear rates compare with 6.3 mm3/10(6) cycles for zirconia-on-ultra-high molecular weight polyethylene tested on the same simulator and representative clinical values for metal-on-polyethylene of 36 mm3/year for heads of 22 mm diameter and a reported range of 60-180 mm3/year for 28 mm heads. These values do not translate directly into numbers of particles, since the metallic debris from metal-on-metal joints is very fine. The number of metallic particles may exceed the number of polyethylene wear particles from an otherwise similar metal-on-polyethylene joint by a factor of 10(3). A detailed discussion of the size and morphology of wear debris and tissue reaction to various forms of debris is beyond the scope of this paper, but the biological response to polymeric, metallic and ceramic wear debris forms a major subject for further study. The present investigation nevertheless confirms the potential of carefully designed and manufactured metal-on-metal total replacement joints for the treatment of diseased and damaged hips. PMID:10718049

Goldsmith, A A; Dowson, D; Isaac, G H; Lancaster, J G

2000-01-01

58

Understanding the role of corrosion in the degradation of metal-on-metal implants.  

PubMed

In metal-on-metal joints the primary concerns in terms of long-term durability relate to corrosion, wear, and their joint (tribocorrosion) effects. The release of ions through corrosion processes and nanoscale debris from wear processes can seriously affect joint integrity and can lead to an adverse biological reaction by the host. In this paper an integrated study of corrosion-wear interactions in serum, Dulbecco's Modified Eagle's Medium and 0.3 per cent NaCl has demonstrated that the biological nature of the fluid affects the total degradation rate and also the level of wear-corrosion interactions. The specific action of proteins in corrosion and tribocorrosion for high-carbon Co-Cr-Mo and low-carbon Co-Cr-Mo alloys is discussed. PMID:16669385

Yan, Y; Neville, A; Dowson, D

2006-02-01

59

Incidence of Groin Pain After Metal-on-Metal Hip Resurfacing  

Microsoft Academic Search

Metal-on-metal hip resurfacing is offered as an alternative to traditional THA for the young and active adult with advanced\\u000a osteoarthritis. However, patients undergoing hip resurfacing may be predisposed to persistent groin pain due to insufficient\\u000a head\\/neck offset, an uncovered acetabular component, or both. We therefore determined the incidence of groin pain after metal-on-metal\\u000a hip resurfacing, its impact on patient function,

Ahmad Bin Nasser; Paul E. BeauleMD; Michelle O’Neill; Paul R. Kim; Anna Fazekas

2010-01-01

60

Effect of swing phase load on metal-on-metal hip lubrication, friction and wear.  

PubMed

There is renewed interest in metal-on-metal (MOM) total hip replacements (THRs), however, variable wear rates have been observed clinically. It is hypothesised that changes in soft tissue tensioning during surgery may alter loading of THRs during the swing phase of gait leading to changes in fluid film lubrication, friction and wear. This study aimed to assess the effect of swing phase load on the lubrication, friction and wear of MOM hip replacements. Theoretical lubrication modelling was carried out using elastohydrodynamic theory. All the governing equations were solved numerically for the lubricant film thickness between the articulating surfaces under the transient dynamic conditions with low and high swing phase loads. Friction testing was completed using a single axis pendulum simulator, simplified loading cycles were applied with low and high swing phase loads. MOM hip replacements were tested in a hip simulator, modified to provide different swing phase loading regimes; a low (100 N) and a high load (as per ISO 14242-1; 280 N). Results demonstrated that the performance of MOM bearings is highly dependent on swing phase load. Hence, changes in the tension of the tissues at surgery and variations in muscle forces may increase swing phase load, reduce lubrication, increase friction and accelerate wear. This may explain some of the variations that have been observed with clinical wear rates. PMID:16143337

Williams, Sophie; Jalali-Vahid, Davood; Brockett, Claire; Jin, Zhongmin; Stone, Martin H; Ingham, Eileen; Fisher, John

2005-09-06

61

The Durom large diameter head acetabular component: early results with a large-diameter metal-on-metal bearing.  

PubMed

Implantation of a large-diameter femoral head prosthesis with a metal-on-metal bearing surface reduces the risk of dislocation, increases the range of movement, minimises the risk of impingement and, in theory, results in little wear. Between February 2004 and March 2007 we implanted 100 consecutive total hip replacements with a metal-on-metal bearing and a large femoral head into 92 patients. There were 51 men and 41 women with a mean age of 50 years (18 to 70) at the time of surgery. Outcome was assessed using the Western Ontario McMaster University osteoarthritis index and the Harris hip score as well as the Devane activity score. These all improved significantly (p < 0.0001). At the last follow-up there were no cases of dislocation, no impingement, a good range of movement and no osteolysis, but seven revisions, two for infection and five for aseptic loosening. The probability of groin pain increased if the other acetabular component inclination exceeded 50 degrees (p = 0.0007). At 4.8 years of follow-up, the projected survival of the Durom acetabular component, with revision for any reason, was 92.4% (sd 2.8) (95% confidence interval 89.6 to 95.2). The design of the component made it difficult both to orientate and seat, which when combined with a poor porous coating, produced unpredictable fixation and a low survival at five years. PMID:20130309

Berton, C; Girard, J; Krantz, N; Migaud, H

2010-02-01

62

Perivascular Lymphocytic Infiltration Is Not Limited to Metal-on-Metal Bearings  

Microsoft Academic Search

Background  Perivascular lymphocytic infiltration (PVLI) suggests an adaptive immune response. Metal hypersensitivity after THA is presumed\\u000a associated with idiopathic pain and aseptic loosening, but its incidence and relationship to metallic wear leading to revision\\u000a are unclear as are its presence and relevance in non-metal-on-metal arthroplasty.\\u000a \\u000a \\u000a \\u000a \\u000a Questions\\/purposes  We compared (1) incidence and severity of PVLI in failed hip metal-on-metal (MoM) to non-MoM implants

Vincent Y. Ng; Adolph V. Lombardi Jr; Keith R. Berend; Michael D. Skeels; Joanne B. Adams

2011-01-01

63

Comparison of ceramic-on-metal and metal-on-metal hip prostheses under adverse conditions.  

PubMed

Ceramic-on-metal (COM) hip replacements, where the head is BIOLOX® Delta ceramic and the liner is CoCrMo alloy, have demonstrated reduced wear under standard simulator conditions compared to metal-on-metal (MOM) bearings. COM hips are now being used clinically around the world. MOM hip resurfacings have raised concerns regarding poor clinical performance and increased in vivo wear was associated with steeply inclined acetabular components and translationally malpositioned components. The aim of this study was to compare the wear rates of MOM and COM total hip prostheses under adverse edge-loading conditions in a hip simulator test. COM and MOM 36 mm hip prostheses were tested in a hip simulator, with liners mounted to provide a clinical inclination angle of 55°. A simplified gait cycle and microseparation conditions were applied for two million cycles in 25% new born calf serum. The overall mean volumetric wear rate of COM bearings under adverse conditions was 0.36 ± 0.55 mm³/million cycles; this was significantly less than MOM wear (1.32 ± 0.91 mm³/million cycles). Under these adverse conditions; the contact zone on the head intersects the rim of the cup causing substantially elevated contact stresses, disrupting the protective boundary and mixed lubrication regime causing changes in types and severity of wear mechanisms. In COM bearings, the harder head does not become damaged when there is lubricant starvation and wear does not accelerate. In conclusion, COM bearings showed reduced wear compared to MOM bearings under standard and adverse clinically relevant simulator conditions and COM bearings may provide an advantage over MOM bearings under edge-loading conditions clinically. PMID:23359608

Williams, Sophie; Al-Hajjar, Mazen; Isaac, Graham H; Fisher, John

2013-01-29

64

New Insights into Wear and Biological Effects of Metal-on-Metal Bearings  

PubMed Central

Background: Despite the renewed interest in metal-on-metal implants in the past two decades, the underlying wear mechanisms and biological effects are still not fully understood. Methods: This paper first reviews the tribology of metal-on-metal bearings, bringing new insights into the interaction of wear and corrosion, and putting the characteristics and the potential origin of wear particles in perspective with the proposed wear mechanisms. It then summarizes the current knowledge on the biological effects of particles and metal ions in relation to these wear mechanisms. Results: Tribochemical reactions play an important role in the wear of metal-on-metal joints. The generated tribomaterial, which progressively forms by mechanical mixing of the uppermost nanocrystalline zone of the metal surface with proteins from the synovial fluid, governs the wear rate and influences the corrosive behavior of the bearing. Nanometer-sized wear particles may initially originate from the passivation layer covering the implant surface and then detach from this tribolayer. The inflammatory response observed surrounding metal-on-metal implants appears to be lower than that around metal-on-polyethylene implants. However, metallic byproducts, which can complex with proteins, may lead to a T lymphocyte-mediated hypersensitivity response. Conclusions: The tribolayer appears to have beneficial effects on the wear rate. Much information has been gained on wear particle characteristics, but the exact mechanisms of particle detachment remain to be further elucidated. Excessive wear along with a hypersensitivity response may be at the origin of the early adverse tissue reactions that have been recently reported in some patients with metal-on-metal implants. Clinical Relevance: Future development of new methods to improve the tribolayer retention and optimize the tribocorrosive properties of the implant may minimize the clinical impact of implant wear and immune responses.

Catelas, Isabelle; Wimmer, Markus A.

2011-01-01

65

Effects of metal-on-metal wear on the host immune system and infection in hip arthroplasty  

PubMed Central

Background and purpose Joint replacement with metal-on-metal (MOM) bearings have gained popularity in the last decades in young and active patients. However, the possible effects of MOM wear debris and its corrosion products are still the subject of debate. Alongside the potential disadvantages such as toxicity, the influences of metal particles and metal ions on infection risk are unclear. Methods We reviewed the available literature on the influence of degradation products of MOM bearings in total hip arthroplasties on infection risk. Results Wear products were found to influence the risk of infection by hampering the immune system, by inhibiting or accelerating bacterial growth, and by a possible antibiotic resistance and heavy metal co-selection mechanism. Interpretation Whether or not the combined effects of MOM wear products make MOM bearings less or more prone to infection requires investigation in the near future.

2010-01-01

66

Early Markers of Nephrotoxicity in Patients With Metal-on-metal Hip Arthroplasty  

Microsoft Academic Search

Background  Metal ions released from arthroplasty devices are largely cleared in urine, leading to high exposure in renal tissues. Validated\\u000a early markers of renal damage are routinely used to monitor workers in heavy metal industries, and renal risk can be quantified\\u000a in these industries. It is unclear if the ion levels in patients with metal-on-metal hips are sufficient to cause renal

Massimo Corradi; Joseph Daniel; Hena Ziaee; Rossella Alinovi; Antonio Mutti; Derek J. W. McMinn

2011-01-01

67

Metal-on-metal surface arthroplasty with a cemented femoral component  

Microsoft Academic Search

Forty-two McMinn metal-on-metal surface arthroplasties were implanted in 23 males and 16 females, average age 47.5 years old. The overall survivorship at 7 years was 79%; with any reoperation surgery as endpoint, 80%; and 93%; with aseptic loosening of the socket and femoral component, respectively. The average Surface Arthroplasty Risk Index of patients who had failed or were at risk

Paul E. Beaulé; Michel Le Duff; Pat Campbell; Fred J. Dorey; Sang Hyun Park; Harlan C. Amstutz

2004-01-01

68

A retrieval analysis of explanted Durom metal-on-metal hip arthroplasties.  

PubMed

Given the recent reports of high failure rates, an improved understanding of the mechanism of failure of large diameter metal-on-metal hip arthroplasties is essential. We present clinical data and tribological analysis of a consecutive series of 74 failed large diameter metal-on-metal hips, comparing the Durom (Zimmer) with the Birmingham hip resurfacing (BHR) (Smith and Nephew). We retrospectively analysed pre-, intra-, and post-operative clinical data and measured the linear wear and component form of the explanted components using a roundness measuring machine. A significantly higher proportion of hips in the Durom group failed as a result of acetabular loosening (p=0.001) and this was supported by evidence of reduced bone in-growth on the backside of the cup. Comparison of roundness measurement revealed that the Durom hip was significantly lower wearing than the BHR (p<0.05) but the Durom femoral components were subject to significantly greater form errors (p<0.001), the pole of the head being flattened by up to 31 microns. Although the Durom hip is low wearing, reduced sphericity of the femoral component may have resulted in equatorial bearing, leading to an increased frictional torque at the cup-bone interface, preventing bone in-growth, and culminating in acetabular loosening. This supports recent clinical findings of high revision rates as a result of acetabular loosening for the Durom metal-on-metal hip system. PMID:22144337

Matthies, Ashley K; Henckel, Johann; Skinner, John A; Hart, Alister J

69

Soft Tissue Imaging in Metal-on-Metal Total Hip Arthroplasty  

Center for Biologics Evaluation and Research (CBER)

Text Version... Summary •• MoM Multiple modes of failure –– Importance of comprehensive systematic ... Summary •• Early and accurate diagnosis important ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

70

Serum Ion Level After Metal-on-metal THA in Patients With Renal Failure  

Microsoft Academic Search

We retrospectively reviewed cementless THAs with metal-on-metal bearings in five patients with chronic renal failure and investigated\\u000a the relations between renal failure and elevated serum cobalt and chromium levels and the side effects of these elevations.\\u000a Serum cobalt and chromium levels were measured by atomic absorption spectrophotometry at a minimum followup of 2.7 years (mean,\\u000a 3.9 years; range, 2.7–6.2 years) in five patients with

Chang Ich Hur; Taek Rim Yoon; Sang Gwon Cho; Eun Kyoo Song; Jong Keun Seon

2008-01-01

71

Metal-on-metal articulation for artificial hip joints: laboratory study and clinical results.  

PubMed

As wear is inevitable with artificial joint replacement, it has to be minimized to avoid possible aseptic loosening following osteolysis due to particle-initiated foreign body reaction. Co-Cr-Mo-C alloys have a long history with only minimum wear when articulating with themselves. This investigation shows that the choice of the alloy has an effect on the wear rate of this articulation couple. Tribological studies in a screening device, a pendulum apparatus and a hip joint simulator showed a marked influence of the environment as well as the diameter of the implants with metal-on-metal articulation. A wear-resistant combination with low friction characteristics has been developed by using a wrought Co-Cr-Mo-C alloy and reducing the implant diameter to 28 mm. Clinical wear rates are comparable with laboratory data and demonstrate the potential of the metal-on-metal articulation to solve the problem of wear-induced osteolysis of hip joint endoprostheses. PMID:8885660

Streicher, R M; Semlitsch, M; Schön, R; Weber, H; Rieker, C

1996-01-01

72

Comparison of alloys and designs in a hip simulator study of metal on metal implants.  

PubMed

Previous studies of metal on metal hip implants have shown that it is possible to obtain substantially lower volumetric wear than with metal on polyethylene pairings. To work toward design optimization, the gravimetric wear of serum lubricated, metal on metal implants was examined in a hip simulator apparatus. Seventeen implant specimens were fabricated from 3 alloys in various combinations of diameter and clearance and wear tested as many as 3 million cycles. Theory was developed to predict the thickness of elastohydrodynamic lubricant films, the linear wear, and wear zone geometry. To help interpret the data, implant diameter and clearance were combined into a single parameter called effective radius. Implants with larger effective radii (6-11 m) tended to experience lower wear, and theory suggested that this was a result of the correspondingly thicker elastohydrodynamic lubricant films providing an enhanced mixed film lubrication. As in most wear testing, the results were scattered but, overall, a low carbon, wrought alloy had lower wear than either a high carbon, cast alloy or a low carbon, commercial alloy. Because of the small number of specimens tested and possible variations in tribologic parameters such as calcium phosphate film formation and surface microgeometry, there was low statistical reliability of the results. PMID:8769332

Medley, J B; Chan, F W; Krygier, J J; Bobyn, J D

1996-08-01

73

The effect of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants.  

PubMed

The influence of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants was investigated in a boundary lubrication regime designed to represent the conditions that occurred some of the time in vivo. These cobalt-chromium-molybdenum alloys were either wrought, with a total carbon content of 0.05 or 0.23 wt %, cast with a solution-annealing procedure or simply as-cast but not solution annealed. Bars of these different alloy grades were subjected to various heat treatments to develop different microstructures. The wear was evaluated in a linear-tracking reciprocating pin-on-plate apparatus with a 25 per cent bovine serum lubricant. The wear was found to be strongly affected by the dissolved carbon content of the alloys and mostly independent of grain size or the carbide characteristics. The increased carbon in solid solution caused reductions in volumetric wear because carbon helped to stabilize a face-centred cubic crystal structure, thus limiting the amount of strain-induced transformation to a hexagonal close-packed crystal structure. Based on the observed surface twining in and around the contact zone and the potentially detrimental effect of the hexagonal close-packed phase, it was postulated that the wear of cobalt-based alloys in the present study was controlled by a deformation mechanism. PMID:16669383

Varano, R; Bobyn, J D; Medley, J B; Yue, S

2006-02-01

74

Metal-on-metal hip resurfacing in patients with pigmented villonodular synovitis: a report of two cases.  

PubMed

Pigmented villonodular synovitis (PVNS) of the hip joint is a rare and benign tumor of the synovia. This local, aggressive, proliferative disorder of the joint synovial membrane can lead to secondary osteoarthritis and represents a small percentage of all patients undergoing total hip replacement (THR). Because of the usually young age of the patients undergoing THR for PVNS, a resurfacing arthroplasty of the hip appears as a beneficial treatment option due to its bone-conserving nature, good joint stability, and ability to easily convert to a THR if needed. This article describes 2 cases of metal-on-metal hip resurfacing in patients with pigmented villonodular synovitis. In patient 1, PVNS was suspected on radiographs but confirmed only after removal of a mass of thick, grey-brown spotted synovia. A complete synovectomy was performed prior to hip resurfacing. Seven years postoperatively, radiographs show secure fixation of the components with no radiolucencies. In patient 2, arthroscopy of the hip joint had been performed 3 months prior, but PVNS had not been diagnosed. Pigmented villonodular synovitis was confirmed during the operation when incising a yellowish nodular mass protruding from the capsule. Granuloma was also found in the inferior and anterior part of the acetabulum. Four years postoperatively, the patient exhibits excellent clinical and radiographic results. Complete surgical removal of all tissue affected with PVNS is the key to a successful resurfacing, which is otherwise technically similar to resurfacing in patients with other etiologies. The mid-term results of the 2 presented cases are satisfying and show the potential of the resurfacing technique for young patients with PVNS of the hip. PMID:20055355

Hoberg, Maik; Amstutz, Harlan C

2010-01-01

75

Serum ion level after metal-on-metal THA in patients with renal failure.  

PubMed

We retrospectively reviewed cementless THAs with metal-on-metal bearings in five patients with chronic renal failure and investigated the relations between renal failure and elevated serum cobalt and chromium levels and the side effects of these elevations. Serum cobalt and chromium levels were measured by atomic absorption spectrophotometry at a minimum followup of 2.7 years (mean, 3.9 years; range, 2.7-6.2 years) in five patients with chronic renal failure and in six patients with normal renal function after THA. Mean serum cobalt concentration was 12.5 microg/L in patients with chronic renal failure; this was more than 100-fold higher than in patients with the same prosthesis type and similar followup period, but with no known renal disease. However, the mean serum chromium concentration was 5.1 microg/L, which was within the normal range in all 11 study patients. Side effects related to elevation of serum cobalt or serum chromium concentration were not identified and overall clinical results were good 4 years after surgery. The serum cobalt level was higher in patients with chronic renal failure. Longer followup is necessary to determine any clinical effects. PMID:18264859

Hur, Chang Ich; Yoon, Taek Rim; Cho, Sang Gwon; Song, Eun Kyoo; Seon, Jong Keun

2008-02-10

76

What Happens to Serum Metal Ion Levels After a Metal-on-Metal Bearing is Removed?  

PubMed

Serum cobalt (Co) and chromium (Cr) levels are commonly used to screen for excessive wear of metal-on-metal hip replacements. However, it is unknown how rapidly these should decline after revision. 25 patients with average Co and Cr ion levels of 56.3?g/L and 20.5?g/L were followed with serial ion level testing post-revision. Over the first 6weeks post-revision, the rate of decline for Co and Cr was approximately 2% per day and this slowed to approximately 1% decline per day over the ensuing 6weeks. This translated to a decline of approximately 80% from the starting value after 6weeks and a decline of approximately 90% after 12weeks post-revision. The rate of decline for both Co and Cr was significantly faster during the first 6weeks (P<0.001). In patients with ultra-high Cr levels>20?g/L, the rate of Cr decline is less predictable and may be protracted leading to persistent elevation above 5?g/L for one year or more post-revision in some cases. PMID:23948123

Ball, Scott T; Severns, Dustyn; Linn, Michael; Meyer, R Scott; Swenson, F Craig

2013-08-12

77

Wear of metal-on-metal hip bearings: metallurgical considerations after hip simulator studies.  

PubMed

Metal-on-metal hip-bearing components with different percentages of carbon content (low and high carbon) were tested in 6 different configurations using a hip joint simulator. The aim of this study was to characterize metallurgical and tribological events occurring at the articulating surfaces of these articulations. Also, ion release was evaluated and correlated with wear. After the test, for the high-carbon components, carbides were observed below the matrix surface. In the low-carbon content components, most carbides were "carbide-free", while a minority were worn below the matrix surface with increased test cycles. In the cast alloy components, some carbides were pulled out resulting in micropits. Scanning microscope electron characterization of the tested specimens showed scratches and holes. The surface showed a dominant severe wear mechanism due to third-body particles. A greater amount of ions was released in the lubricant used during the wear test for the smaller diameter compared with the bigger one. This study showed that the metallurgical and tribological events taking place at the articulating surfaces of metal-metal hip implants are numerous and complex. The surface morphology after the test showed the effect of more critical working conditions with smaller diameters. PMID:22198601

Affatato, Saverio; Traina, Francesco; Ruggeri, Oddone; Toni, Aldo

2011-12-01

78

Single-layer metal-on-metal islands driven by strong time-dependent forces.  

PubMed

Nonlinear transport properties of single-layer metal-on-metal islands driven with strong static and time-dependent forces are studied. We apply a semiempirical lattice model and use master-equation and kinetic Monte Carlo simulation methods to compute observables such as the velocity and the diffusion coefficient. Two types of time-dependent driving are considered: a pulsed rotated field and an alternating field with a zero net force (electrophoretic ratchet). Small islands up to 12 atoms were studied in detail with the master-equation method and larger ones with simulations. Results are presented mainly for a parametrization of Cu on Cu(001) surface, which has been the main system of interest in several previous studies. The main results are that the pulsed field can increase the current in both diagonal and axis direction when compared to static field, and there exists a current inversion in the electrophoretic ratchet. Both of these phenomena are a consequence of the coupling of the internal dynamics of the island with its transport. In addition to the previously discovered "magic size"effect for islands in equilibrium, a strong odd-even effect was found for islands driven far out of equilibrium. Master-equation computations revealed nonmonotonous behavior for the leading relaxation constant and effective Arrhenius parameters. Using cycle optimization methods, typical island transport mechanisms are identified for small islands. PMID:22400512

Kauttonen, Janne; Merikoski, Juha

2012-01-03

79

[MRI investigations in patients with problems due to metal-on-metal implants].  

PubMed

Until recently, metal-on-metal (MoM) hip implants were commonly used for joint replacement and resurfacings. Their use has rapidly declined following reports of Frühversagen and soft tissue disease caused by the release of metal debris from the prosthesis. Detection of these soft tissue lesions has proven difficult using conventional imaging techniques and blood metal ion tests. Current guidelines recommend the use of imaging modalities including metal artefact reduction sequence (MARS) magnetic resonance imaging (MRI), computed tomography and ultrasound but provide little indication which is best. MARS significantly reduces the susceptibility artefact induced by the presence of metal objects, thereby producing diagnostic quality images that can be shared with other physicians and compared over time. The clinical interpretation of MRI findings of solid pseudotumours and severe muscle atrophy is straightforward: revision is usually recommended. However, the most common MRI findings are of a cystic pseudotumour and minor muscle wasting. In these cases decision-making is difficult and we currently use multi-disciplinary and multi-colleague based meetings to make decisions regarding patient management. This article presents a comparison of imaging modalities and an update on the interpretation of MARS MRI for the investigation of patients with MoM hip implants.The English full-text version of this article is available at Springer Link (under "Supplemental"). PMID:23912305

Hart, A

2013-08-01

80

Metal presence in hair after metal-on-metal resurfacing arthroplasty.  

PubMed

The elevation of metal levels in serum and urine during post-operative follow-up is a frequent find following the implantation of certain models of metal-on-metal hip prostheses. Among 45 patients with the same resurfacing prostheses, chromium (Cr) and cobalt (Co) levels in serum and urine were determined at 3, 4, 5, and 6 years after surgery. In the same period, levels of Cr, Co and molibdene (Mo) in scalp hair were also measured. Mean Cr and Co levels in serum were 8.29?µg/L (SD 17.97) and 8.38?µg/L (SD 21.97), respectively, whereas in urine levels were 16.20?µg/L (SD SD 32.55) and 75.40?µg/L (SD 190.86), respectively. In hair, mean Cr level were 163.27?µg/g (SD 300.62), mean Co level 61.98?µg/g (SD 126.48), and Mo 31.36?µg/g (SD 37.86). A high concordance was observed between chromium-urine and chromium-serum and between cobalt-urine and cobalt-hair. A moderate concordance was present between cobalt-urine and cobalt-serum, and between cobalt-hair and cobalt-serum. Eleven patients required revision surgery, five of them due to metallosis and periarticular cyst. At 1 year after reintervention, analytics were performed again and the following decrease rates were found: 42.8% in Cr levels, 51.1% in Mo levels, and 90.3% in Co levels. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:2025-2031, 2013. PMID:23893786

Rodríguez de la Flor, María; Hernández-Vaquero, Daniel; Fernández-Carreira, José Manuel

2013-07-24

81

Wear behaviour of cobalt-chromium-molybdenum alloys used in metal-on-metal hip implants  

NASA Astrophysics Data System (ADS)

The influence of carbon (C) content, microstructure, crystallography and mechanical properties on the wear behaviour of metal-on-metal (MM) hip implants made from commercially available cobalt-chromium-molybdenum (CoCrMo) alloys designated as American Society of Testing and Materials (ASTM) grade F1537, F75 and as-cast were studied in this work. The as-received bars of wrought CoCrMo alloys (ASTM F1537 of either about 0.05% or 0.26% C) were each subjected to various heat treatments to develop different microstructures. Pin and plate specimens were fabricated from each bar and were tested against each other using a linear reciprocating pin-on-plate apparatus in 25% by volume bovine serum solution. The applied normal load was 9.81 N and the reciprocating plate had a sinusoidal velocity with an average speed of 26 mm/s. The wear was measured gravimetrically and it was found to be most strongly affected by alloy C content, irrespective of grain size or carbide morphology. More precisely, the wear behaviour was directly correlated to the dissolved C content of the alloys. Increased C in solid-solution coincided with lower volumetric wear since C helps to stabilize the face-centred cubic (FCC) crystal structure thus limiting the amount of strain induced transformation (SIT) to the hexagonal close-packed crystal structure (HCP). Based on the observed surface twinning in and around the contact zone and the potentially detrimental effect of the HCP phase, it was postulated that the MM wear behaviour of CoCrMo alloys in the present study was controlled by a deformation mechanism, rather than corrosion or tribochemical reactions.

Varano, Rocco

82

Effect of bearing geometry and structure support on transient elastohydrodynamic lubrication of metal-on-metal hip implants  

Microsoft Academic Search

An effective lubrication can significantly reduce wear of metal-on-metal artificial hip joints. The improvement of the lubrication can be achieved through the optimisation of the bearing geometry in terms of a small clearance and\\/or the structural support such as a polyethylene backing underneath a metallic bearing in a sandwich acetabular cup form. The separate effects of these two factors on

Feng Liu; Zhongming Jin; Paul Roberts; Peter Grigoris

2007-01-01

83

Outcome and serum ion determination up to 11 years after implantation of a cemented metal-on-metal hip prosthesis  

PubMed Central

Background and purpose Little is known about the long-term outcome of cemented metal-on-metal hip arthroplasties. We evaluated a consecutive series of metal-on-metal polyethylene-backed cemented hip arthroplasties implanted in patients under 60 years of age. Methods 109 patients (134 joint replacements) were followed prospectively for mean 9 (7–11) years. The evaluation included clinical score, radiographic assessment, and blood sampling for ion level determination. Results At the final review, 12 hips had been revised, mainly because of aseptic loosening of the socket. Using revision for aseptic loosening as the endpoint, the survival rate at 9 years was 91% for the cup and 99% for the stem. In addition, 35 hips showed radiolucent lines at the bone-cement interface of the acetabulum and some were associated with osteolysis. The median serum cobalt and chromium levels were relatively constant over time, and were much higher than the detection level throughout the study period. The cobalt level was 1.5 ?g/L 1 year after implantation, and 1.44 ?g/L 9 years after implantation. Interpretation Revisions for aseptic loosening and radiographic findings in the sockets led us to halt metal-on-metal-backed polyethylene cemented hip arthroplasty procedures. If the rigidity of the cemented socket is a reason for loosening, excessive release of metal ions and particles may be involved. Further investigations are required to confirm this hypothesis and to determine whether subluxation, microseparation, and hypersensitivity also play a role.

Lazennec, Jean-Yves; Poupon, Joel; Rousseau, Marc-Antoine; Roy, Carine; Ravaud, Philippe; Catonne, Yves

2009-01-01

84

A novel technique for the removal of well-fixed cementless, large-diameter metal-on-metal acetabular components.  

PubMed

Removing well-fixed cementless acetabular components can be a challenge for every orthopedic surgeon involved in revision hip arthroplasty. Forceful removal of such components often leads to acetabular bone loss and compromises reimplantation of a new socket. Instruments like the Explant Acetabular Cup Removal System (Zimmer, Warsaw, Ind) are developed to avoid such issues. We report a novel technique, cementing a polyethylene liner inside the uncemented metal-on-metal shell and using systems such as the Explant to safely extract it without the need for matching large-diameter heads. We successfully used this technique on 3 occasions and recommend its use. PMID:18555640

Olyslaegers, Christophe; Wainwright, Tom; Middleton, Robert G

2008-06-13

85

Contact mechanics of metal-on-metal hip implants employing a metallic cup with a UHMWPE backing.  

PubMed

The contact mechanics in metal-on-metal hip implants employing a cobalt chromium acetabular cup with an ultra-high molecular weight polyethylene (UHMWPE) backing were analysed in the present study using the finite element method. A general modelling methodology was developed to examine the effects of the interfacial boundary conditions between the UHMWPE backing and a titanium shell for cementless fixation, the coefficient of friction and the loading angle on the predicted contact pressure distribution at the articulating surfaces. It was found that the contact mechanics at the bearing surfaces were significantly affected by the UHMWPE backing. Consequently, a relatively constant pressure distribution was predicted within the contact conjunction, and the maximum contact pressure occurred towards the edge of the contact. On the other hand, the interfacial boundary condition between the UHMWPE backing and the titanium shell, the coefficient of friction and the loading angle were found to have a negligible effect on the contact mechanics at the bearing surfaces. Overall, the magnitude of the contact pressure was significantly reduced, compared with a similar cup without the UHMWPE backing. The importance of the UHMWPE backing on the tribological performance of metal-on-metal hip implants is discussed. PMID:12807161

Liu, F; Jin, Z M; Grigoris, P; Hirt, F; Rieker, C

2003-01-01

86

A safe zone for acetabular component position in metal-on-metal hip resurfacing arthroplasty: winner of the 2012 HAP PAUL award.  

PubMed

A safe zone for acetabular component positioning in hip resurfacing (RAIL: Relative Acetabular Inclination Limit) was calculated based on implant size and acetabular inclination angle (AIA). For AIA below the RAIL, there were no adverse wear failures or dislocations, and only 1% of cases with ion levels above 10 ?g/L. Other than high inclination angle and small bearing size, female gender was the only other factor that correlated with high ion levels in the multivariate analysis. Seven hundred sixty-one hip resurfacing cases are included in this study. The UCLA activity score, femoral shaft angle, body mass index, weight, American Society of Anesthesiologists score, combined range of motion, diagnosis, age, gender, implant brand, AIA, bearing size, and duration of implantation were analyzed to determine the potential risk factors for elevated metal ion levels. These findings apply to sub hemispheric metal-on-metal bearings with similar coverage arcs as the Biomet and Corin hip resurfacing brands. Additional problems may occur when these bearings are connected with trunions on stems for total hip arthroplasty. PMID:23540536

Liu, Fei; Gross, Thomas P

2013-03-26

87

Electrochemical instrumentation of a hip simulator: a new tool for assessing the role of corrosion in metal-on-metal hip joints.  

PubMed

Polyethylene wear debris induced osteolysis has triggered investigations to find alternative material combinations to the well-established metal-on-polyethylene hip implants. Owing to some early successful clinical cases, metal-on-metal (MoM) hip replacements have been attracting more and more interest. There is, however, considerable concern about the propensity of MoM hip replacements to release metal ions and fine, nanometre-scale metallic wear debris. The long-term effect from released metal ions and wear particles is still not clear. To date, all the work on hip simulators focused on assessing mass losses damage has been referred to as 'wear'. However, it is known in the field of tribocorrosion that mechanical removal of the passive layer on Co-Cr alloys can significantly enhance corrosion activity. In total joint replacements, it is possible that corrosion plays a significant role. However, no one has ever tried to extract, on a hip simulator, what proportion of the damage is due to mechanical processes and the corrosion processes. This paper describes the first instrumentation of an integrated hip joint simulator to provide in-situ electrochemical measurements in real time. The open circuit potential results are reported to assess the corrosion regime in the absence and presence of movement at the bearing surfaces. The importance of these measurements is that the real damage mechanisms can be assessed as a function of the operating cycle. PMID:21218689

Yan, Y; Neville, A; Dowson, D; Williams, S; Fisher, J

2010-11-01

88

Transplacental transfer of cobalt and chromium in patients with metal-on-metal hip arthroplasty: a controlled study.  

PubMed

Metal-on-metal bearings are being increasingly used in young patients. The potential adverse effects of systemic metal ion elevation are the subject of ongoing investigation. The purpose of this study was to investigate whether cobalt and chromium ions cross the placenta of pregnant women with a metal-on-metal hip resurfacing and reach the developing fetus. Whole blood levels were estimated using high-resolution inductively-coupled plasma mass spectrometry. Our findings showed that cobalt and chromium are able to cross the placenta in the study patients with metal-on-metal hip resurfacings and in control subjects without any metal implants. In the study group the mean concentrations of cobalt and chromium in the maternal blood were 1.39 microg/l (0.55 to 2.55) and 1.28 microg/l (0.52 to 2.39), respectively. The mean umbilical cord blood concentrations of cobalt and chromium were comparatively lower, at 0.839 microg/l (0.42 to 1.75) and 0.378 microg/l (0.14 to 1.03), respectively, and this difference was significant with respect to chromium (p < 0.05). In the control group, the mean concentrations of cobalt and chromium in the maternal blood were 0.341 microg/l (0.18 to 0.54) and 0.199 microg/l (0.12 to 0.33), and in the umbilical cord blood they were 0.336 microg/l (0.17 to 0.5) and 0.194 microg/l (0.11 to 0.56), respectively. The differences between the maternal and umbilical cord blood levels in the controls were marginal, and not statistically significant (p > 0.05). The mean cord blood level of cobalt in the study patients was significantly greater than that in the control group (p < 0.01). Although the mean umbilical cord blood chromium level was nearly twice as high in the study patients (0.378 microg/l) as in the controls (0.1934 microg/l), this difference was not statistically significant. (p > 0.05) The transplacental transfer rate was in excess of 95% in the controls for both metals, but only 29% for chromium and 60% for cobalt in study patients, suggesting that the placenta exerts a modulatory effect on the rate of metal ion transfer. PMID:17356138

Ziaee, H; Daniel, J; Datta, A K; Blunt, S; McMinn, D J W

2007-03-01

89

Immune responses in patients with metal-on-metal hip articulations: a long-term follow-up.  

PubMed

Metal-on-metal (MoM) hip bearings are being inserted into ever-younger patients. The effects on the immune system of chronic exposure are unknown. We investigated the immune response of patients with MoM hip bearings. In patients with MoM implants, the expression of antigen-presenting cell (APC) surface molecules (CD86 and HLA-DR) was seen to be significantly higher (P < .05) than control group. High levels of APC surface molecules suggest an activated state and attempts to propagate an immune response. However, in the same group, the expression of T-cell markers (CD3 and CD28) was low, indicating a small T-cell population. This suggests, despite the activation of APCs, that T cells down-regulate immune responses in MoM articulations. Conversely, in metal-on-polyethylene articulations, expression of T-cell molecules was elevated and expression of APC molecules lowered. PMID:18534468

Whittingham-Jones, Paul M; Dunstan, Edward; Altaf, Huwaidha; Cannon, Stephen R; Revell, Peter A; Briggs, Timothy W R

2008-04-15

90

A comparative study on medium-term results of cementless acetabular components with metal-on-metal and metal-on-polyethylene articulations  

Microsoft Academic Search

The purpose of this study was to evaluate the medium-term clinical and radiological outcomes of two metal-backed acetabular\\u000a cups with metal-on-metal and metal-on-polyethylene joint couples, in patients unselected for age. Seventy-five metal-on-polyethylene\\u000a CLS expansion cups were implanted in 70 patients and 66 metal-on-metal Fitek cups were implanted in 65 patients. The average\\u000a age at surgery in the two groups was

F. Cozzolino; M. Mariconda; L. Costa; D. Scognamiglio; A. Cozzolino; D. Marinò; C. Milano

2002-01-01

91

pH effects on catalytic ozonation of carboxylic acids with metal on metal oxides catalysts  

Microsoft Academic Search

Summary The pH influence on the catalytic ozonation of small carboxylic acids (succinic (SA), chloroacetic (CAA) and pyruvic (PA) acids) was studied and compared to ozonation alone. In the acidic systems, the conversion of these carboxylic acids and total organic carbon (TOC) during the catalytic ozonation is mainly due to the catalytic effect. Experiments on SA indicate that in the

Nathalie Karpel Vel Leitner; Hongxiang Fu

2005-01-01

92

Chromium and cobalt ion concentrations in blood and serum following various types of metal-on-metal hip arthroplasties  

PubMed Central

Background and purpose Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties. Methods Studies were searched for in the Medline database, Embase, and the Cochrane Database of Systematic Reviews. Highest mean or median ion concentrations of Cr and Co after a minimum of 1 year of follow-up were extracted and grouped according to sample- and articulation type, and average values were calculated. Results 43 studies were included and 16 different MoM implants were identified. For the different types of bearings, average ion concentrations and range were calculated from the mean or median ion concentration. The average Cr concentration ranged between 0.5 and 2.5 ?g/L in blood and between 0.8 and 5.1 ?g/L in serum. For Co, the range was 0.7–3.4 ?g/L in blood and 0.3–7.5 ?g/L in serum. Interpretation When the average blood ion concentrations calculated for the different implants, together with the concentrations measured in the individual studies, were compared with the upper acceptable limit for Cr and Co in blood, no clear pattern was recognized. Furthermore, we were unable to detect any clear difference in ion concentrations between different types of implants (THA and resurfacing).

2013-01-01

93

Lymphoid Aggregates That Resemble Tertiary Lymphoid Organs Define a Specific Pathological Subset in Metal-on-Metal Hip Replacements  

PubMed Central

Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) has been used to describe the histological lesion associated with metal-on-metal (M-M) bearings. We tested the hypothesis that the lymphoid aggregates, associated with ALVAL lesions resemble tertiary lymphoid organs (TLOs). Histopathological changes were examined in the periprosthetic tissue of 62 M-M hip replacements requiring revision surgery, with particular emphasis on the characteristics and pattern of the lymphocytic infiltrate. Immunofluorescence and immunohistochemistry were used to study the classical features of TLOs in cases where large organized lymphoid follicles were present. Synchrotron X-ray fluorescence (XRF) measurements were undertaken to detect localisation of implant derived ions/particles within the samples. Based on type of lymphocytic infiltrates, three different categories were recognised; diffuse aggregates (51%), T cell aggregates (20%), and organised lymphoid aggregates (29%). Further investigation of tissues with organised lymphoid aggregates showed that these tissues recapitulate many of the features of TLOs with T cells and B cells organised into discrete areas, the presence of follicular dendritic cells, acquisition of high endothelial venule like phenotype by blood vessels, expression of lymphoid chemokines and the presence of plasma cells. Co-localisation of implant-derived metals with lymphoid aggregates was observed. These findings suggest that in addition to the well described general foreign body reaction mediated by macrophages and a T cell mediated type IV hypersensitivity response, an under-recognized immunological reaction to metal wear debris involving B cells and the formation of tertiary lymphoid organs occurs in a distinct subset of patients with M-M implants.

Barone, Francesca; Hardie, Debbie L.; Matharu, Gulraj S.; Davenport, Alison J.; Martin, Richard A.; Grant, Melissa; Mosselmans, Frederick; Pynsent, Paul; Sumathi, Vaiyapuri P.; Addison, Owen; Revell, Peter A.; Buckley, Christopher D.

2013-01-01

94

(v) Simulation and measurement of wear in metal-on-metal bearings in vitro- understanding the reasons for increased wear  

PubMed Central

A new Stratified Approach For Enhanced Reliability (SAFER) pre-clinical simulation testing of joint prostheses has been described in a preceding paper in this volume. The application of SAFER in vitro simulation and testing to metal-on-metal bearings is described in this review paper. The review aims to provide further understanding of the reasons for, and causes of, increased wear in metal-on-metal hips in a proportion of patients. Variation in positioning (mal-positioning) of the head and cup in hip prostheses results in the head contacting the rim of the cup and producing increased wear. Variation in both translational and rotational positioning has been investigated. Variation in translational positioning of the centres of the head and cup, which is not detected on radiographs, is a frequent occurrence clinically and can result in a substantial increase in wear rate. The variation in translational positioning acts synergistically with variation in rotational positioning to produce substantial increases in wear. These recent findings are consistent with the wear mechanisms and formation of stripe wear reported for ceramic-on-ceramic bearings over a decade ago, and provide insight into the reasons for the variation and increases in the wear rate found clinically in metal-on-metal hips in specific patients, which may cause premature failure.

Fisher, John; Al Hajjar, Mazen; Williams, Sophie; Tipper, Joanne; Ingham, Eileen; Jennings, Louise

2012-01-01

95

Activation of Noble Metals on Metal-Carbide Surfaces: Novel Catalysts for CO Oxidation, Desulfurization and Hydrogenation Reactions  

SciTech Connect

This perspective article focuses on the physical and chemical properties of highly active catalysts for CO oxidation, desulfurization and hydrogenation reactions generated by depositing noble metals on metal-carbide surfaces. To rationalize structure-reactivity relationships for these novel catalysts, well-defined systems are required. High-resolution photoemission, scanning tunneling microscopy (STM) and first-principles periodic density-functional (DF) calculations have been used to study the interaction of metals of Groups 9, 10 and 11 with MC(001) (M = Ti, Zr, V, Mo) surfaces. DF calculations give adsorption energies that range from 2 eV (Cu, Ag, Au) to 6 eV (Co, Rh, Ir). STM images show that Au, Cu, Ni and Pt grow on the carbide substrates forming two-dimensional islands at very low coverage, and three-dimensional islands at medium and large coverages. In many systems, the results of DF calculations point to the preferential formation of admetal-C bonds with significant electronic perturbations in the admetal. TiC(001) and ZrC(001) transfer some electron density to the admetals facilitating bonding of the adatom with electron-acceptor molecules (CO, O{sub 2}, C{sub 2}H{sub 4}, SO{sub 2}, thiophene, etc.). For example, the Cu/TiC(001) and Au/TiC(001) systems are able to cleave both S-O bonds of SO{sub 2} at a temperature as low as 150 K, displaying a reactivity much larger than that of TiC(001) or extended surfaces of bulk copper and gold. At temperatures below 200 K, Au/TiC is able to dissociate O{sub 2} and perform the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(001) or Au(111), a Au/TiC(001) surface displays an activity for the hydrodesulfurization of thiophene higher than that of conventional Ni/MoS{sub x} catalysts. In general, the Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces. Thus, metal carbides are excellent supports for enhancing the chemical reactivity of noble metals.

Rodriguez J. A.; Illas, F.

2012-01-01

96

Individual motion patterns during gait and sit-to-stand contribute to edge-loading risk in metal-on-metal hip resurfacing.  

PubMed

The occurrence of pseudotumours (soft tissue masses relating to the hip joint) following metal-on-metal hip resurfacing arthroplasty has been associated with higher than normal bearing wear and high serum metal ion levels although both these findings do not necessarily coexist. The purpose of this study was to examine patient activity patterns and their influence on acetabular component edge loading in a group of subjects with known serum metal ion levels. Fifteen subjects with metal-on-metal hip resurfacing arthroplasty (eight males and seven females) were recruited for motion analysis followed by computed tomography scans. They were divided into three groups based on their serum metal ion levels and the orientation of their acetabular component: well-positioned acetabular component with low metal ions, mal-positioned acetabular component with low metal ions and mal-positioned acetabular component with high ions. A combination of motion analysis, subject-specific modelling (AnyBody Modeling System, Aalborg, Denmark) and computed tomography measurements was used to calculate dynamically the contact patch-to-rim distance for each subject during gait and sit-to-stand. The contact-pitch-to-rim distance for the high ion group was significantly lower (p<0.001) than for the two low ion groups (well-positioned and mal-positioned) during the stance phase of gait (0%-60%) and loading phase of sit-to-stand (20%-80%). The results of this study, in particular, the significant difference between the two mal-positioned groups, suggest that wear of metal-on-metal hip resurfacing arthroplasty is not only affected by acetabular cup orientation but also influenced by individual patient activity patterns. PMID:23636762

Mellon, Stephen J; Grammatopoulos, George; Andersen, Michael S; Pegg, Elise C; Pandit, Hemant G; Murray, David W; Gill, Harinderjit S

2013-04-16

97

Is increased modularity associated with increased fretting and corrosion damage in metal-on-metal total hip arthroplasty devices?: a retrieval study.  

PubMed

This retrieval study documents taper damage at modular interfaces in retrieved MOM THA systems and investigates if increased modularity is associated with increased fretting and corrosion. One hundred thirty-four (134) heads and 60 stems (41 modular necks) of 8 different bearing designs (5 manufacturers) were analyzed. Damage at the shell-liner interface of 18 modular CoCr acetabular liners and the corresponding 11 acetabular shells was also evaluated. The results of this study support the hypothesis that fretting and corrosion damage occurs at a variety of modular component interfaces in contemporary MOM THAs. We also found that modularity of the femoral stem was associated with increased damage at the head. An analysis of component and patient variables revealed that dissimilar alloy pairing, larger head sizes, increased medio-lateral offsets and longer neck moment arms were all associated with increased taper damage at the modular interfaces. PMID:23910820

Higgs, Genymphas B; Hanzlik, Josa A; MacDonald, Daniel W; Gilbert, Jeremy L; Rimnac, Clare M; Kurtz, Steven M

2013-08-01

98

Experience with the Metasul total hip bearing system.  

PubMed

The author and Sulzer Medical Technology Ltd, Switzerland, have developed a new generation of metal on metal bearing total hip joints. The design is different than the McKee type prostheses in that the cobalt chrome alloy heads and cups (Metasul) are of the highest precision with controlled loose fitting. These allow low friction and low wear of approximately 5 micrometers per year. It is anticipated that debris related late loosening will be avoided by the use of this design. Approximately 30,000 Metasul hearings have been produced. The first 110 Weber metal on metal hip implants have been analyzed. No adverse effects from the wear of the new metal on metal components have been noted in this series. PMID:8769324

Weber, B G

1996-08-01

99

Influence of head size on the development of metallic wear and on the characteristics of carbon layers in metal-on-metal hip joints  

PubMed Central

Background and purpose Particles originating from the articulating surfaces of hip endoprostheses often induce an inflammatory response, which can be related to implant failure. We therefore analyzed the metal content in capsular tissue from 44 McKee-Farrar metal-on-metal hip prostheses (with 3 different head sizes) and we also analyzed the morphological structure of layers located on articulating surfaces. Methods Atomic absorption spectrometry (AAS) was used to analyze the metal content in capsular tissue. Visually detectable carbon layers located on the articulating surfaces were evaluated using scanning electron microscopy (SEM), energy-dispersive Xray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Results Metallic debris was detected in all capsular tissue samples but no statistically significant differences in metal content were found in relation to implant head size. The morphological characteristics of the different layer zones allowed an exact analysis of contact and non-contact areas. Furthermore, surface layers appear to have a protective function because they can prevent sharp-edged particles from damaging the prostheses surface. Interpretation The implant head size does not appear to influence the amount of metallic debris. The layers obviously act like a lubricating agent because the protection function does not occur in regions without layers where the metal surface often shows numerous scratches. As layers are not generated immediately after the implantation of hip prostheses, these findings may at least partially explain the high amount of wear early after implantation.

Sprecher, Christoph M; Wimmer, Markus A; Milz, Stefan; Taeger, Georg

2009-01-01

100

Characterisation of wear debris from UHMWPE on zirconia ceramic, metal-on-metal and alumina ceramic-on-ceramic hip prostheses generated in a physiological anatomical hip joint simulator  

Microsoft Academic Search

There is currently much interest in the characterisation of wear debris from different types of artificial hip joints. There have been numerous studies on the wear of UHMWPE in hip joint simulators, but relatively few studies on the wear of alternative materials such as metal-on-metal (MOM) and ceramic-on-ceramic (COC). The aim of this study was to compare the wear volumes

J. L Tipper; P. J Firkins; A. A Besong; P. S. M Barbour; J Nevelos; M. H Stone; E Ingham; J Fisher

2001-01-01

101

Asymptomatic prospective and retrospective cohorts with metal-on-metal hip arthroplasty indicate acquired lymphocyte reactivity varies with metal ion levels on a group basis.  

PubMed

Some tissues from metal-on-metal (MoM) hip arthroplasty revisions have shown evidence of adaptive-immune reactivity (i.e., excessive peri-implant lymphocyte infiltration/activation). We hypothesized that, prior to symptoms, some people with MoM hip arthroplasty will develop quantifiable metal-induced lymphocyte reactivity responses related to peripheral metal ion levels. We tested three cohorts (Group 1: n = 21 prospective longitudinal MoM hip arthroplasty; Group 2: n = 17 retrospective MoM hip arthroplasty; and Group 3: n = 20 controls without implants). We compared implant position, metal-ion release, and immuno-reactivity. MoM cohorts had elevated (p < 0.01) amounts of serum Co and Cr compared to controls as early as 3 months post-op (Group 1:1.2 ppb Co, 1.5 ppb Cr; Group 2: 3.4 ppb Co, 5.4 ppb Cr; Group 3: 0.01 ppb Co, 0.1 ppb Cr). However, only after 1-4 years post-op did 56% of Group 1 develop metal-reactivity (vs. 5% pre-op, metal-LTT, SI > 2), compared with 76% of Group 2, and 15% of Group 3 controls (patch testing was a poor diagnostic indicator with only 1/21 Group 1 positive). Higher cup-abduction angles (50° vs. 40°) in Group 1 were associated with higher serum Cr (p < 0.07). However, sub-optimal cup-anteversion angles (9° vs. 20°) had higher serum Co (p < 0.08). Serum Cr and Co were significantly elevated in reactive versus non-reactive Group-1 participants (p < 0.04). CD4+CD69+ T-helper lymphocytes (but not CD8+) and IL-1?, IL-12, and IL-6 cytokines were all significantly elevated in metal-reactive versus non-reactive Group 1 participants. Our results showed that lymphocyte reactivity to metals can develop within the first 1-4 years after MoM arthroplasty in asymptomatic patients and lags increases in metal ion levels. This increased metal reactivity was more prevalent in those individuals with extreme cup angles and higher amounts of circulating metal. PMID:22941579

Hallab, Nadim J; Caicedo, Marco; McAllister, Kyron; Skipor, Anastasia; Amstutz, Harlan; Jacobs, Joshua J

2012-08-31

102

An in vitro study of the reduction in wear of metal-on-metal hip prostheses using surface-engineered femoral heads.  

PubMed

Although the wear of existing metal-on-metal (MOM) hip prostheses (1 mm3/10(6) cycles) is much lower than the more widely used polyethylene-on-metal bearings, there are concerns about the toxicity of metal wear particles and elevated metal ion levels, both locally and systemically, in the human body. The aim of this study was to investigate the possibility of reducing the volume of wear, the concentration of metal debris and the level of metal ion release through using surface-engineered femoral heads. Three thick (8-12 microm) coatings (TiN, CrN and CrCN) and one thin (2 microm) coating (diamond-like carbon, DLC), were evaluated on the femoral heads when articulating against high carbon content cobalt-chromium alloy acetabular inserts (HC CoCrMo) and compared with a clinically used MOM cobalt-chromium alloy bearing couple using a physiological anatomical hip joint simulator (Leeds Mark II). This study showed that CrN, CrCN and DLC coatings produced substantially lower wear volumes for both the coated femoral heads and the HC CoCrMo inserts. The TiN coating itself had little wear, but it caused relatively high wear of the HC CoCrMo inserts compared with the other coatings. The majority of the wear debris for all half-coated couples comprised small, 30 nm or less, CoCrMo metal particles. The Co, Cr and Mo ion concentrations released from the bearing couples of CrN-, CrCN- and DLC-coated heads articulating against HC CoCrMo inserts were at least 7 times lower than those released from the clinical MOM prostheses. These surface-engineered femoral heads articulating on HC CoCrMo acetabular inserts produced significantly lower wear volumes and rates, and hence lower volumetric concentrations of wear particles, compared with the clinical MOM prosthesis. The substantially lower ion concentration released by these surface-engineered components provides important evidence to support the clinical application of this technology. PMID:12206518

Fisher, J; Hu, X Q; Tipper, J L; Stewart, T D; Williams, S; Stone, M H; Davies, C; Hatto, P; Bolton, J; Riley, M; Hardaker, C; Isaac, G H; Berry, G; Ingham, E

2002-01-01

103

Peri-acetabular bone mineral density in total hip replacement  

PubMed Central

Objectives To quantify and compare peri-acetabular bone mineral density (BMD) between a monoblock acetabular component using a metal-on-metal (MoM) bearing and a modular titanium shell with a polyethylene (PE) insert. The secondary outcome was to measure patient-reported clinical function. Methods A total of 50 patients (25 per group) were randomised to MoM or metal-on-polyethlene (MoP). There were 27 women (11 MoM) and 23 men (14 MoM) with a mean age of 61.6 years (47.7 to 73.2). Measurements of peri-prosthetic acetabular and contralateral hip (covariate) BMD were performed at baseline and at one and two years’ follow-up. The Western Ontario and McMaster Universities osteoarthritis index (WOMAC), University of California, Los Angeles (UCLA) activity score, Harris hip score, and RAND-36 were also completed at these intervals. Results At two years, only zone 1 showed a loss in BMD (-2.5%) in MoM group compared with a gain in the MoP group (+2.2%). Zone 2 showed loss in both groups (-2.2% for MoM; -3.9% for MoP) and zones 3 and 4 a gain in both groups (+0.1% for MoM; +3.3% for MoP). No other between-group differences were detected. When adjusting for BMD of the contralateral hip, no differences in BMD were observed. The only significant differences in functional scores at two years were higher UCLA activity (7.3 (sd 1.2) vs 6.1 (sd 1.5); p = 0.01) and RAND-36 physical function (82.1 (sd 13.0) vs 64.5 (sd 26.4); p = 0.02) for MoM bearings versus MoP. One revision was performed in the MoM group, for aseptic acetabular loosening at 11 months. Conclusions When controlling for systemic BMD, there were no significant differences between MoM and MoP groups in peri-acetabular BMD. However, increasing reports of adverse tissue reactions with large head MoM THR have restricted the use of the monoblock acetabular component to resurfacing only.

Gauthier, L.; Dinh, L.; Beaule, P. E.

2013-01-01

104

[Clinical Wear Behaviour of UHMW Polyethylene Cups Paired with Metal and Ceramic Ball Heads in Comparison to Metal-on-Metal Pairings of Hip Joint Replacements.].  

PubMed

In the course of 30 years' hip endoprosthetics, a number of material combinations for the cups and balls of total hip prostheses have proven successful under clinical conditions. Favourably priced hip prostheses with polyethylene cups and metal balls are available for very old patients with a moderate range of activity. Polyethylene wear of 100-300 microm per year is to be expected with these models. Ceramic balls (aluminium oxide for diameters 32 and 28 mm and zirconium oxide for 22 mm) paired with polyethylene cups are recommended for patients with a life expectancy of 10 to 20 years, because the expected polyethylene wear rate with this material combination is only 50-150 microm per annum. In other words, the life cycle of the polyethylene cup is doubled, when it is paired with a ceramic ball. A similar polyethylene wear rate is also to be expected with oxygen-deephardened TiAlNb metal balls, which are currently the subject of a clinical field study. Last but not least, CoCrMoC metal/metal and AI2O3 ceramic/ceramic pairings, which have the lowest wear rate of 2 to 20 microm/year. are available for highly active patients with a life expectancy of more than 20 years. As far as the cup/ball pairing is concerned and under the current pressure of costs, the surgeon should be able to select the optimum hip prosthesis model for every patient from these three categories. PMID:20470544

Semlitsch, M; Willert, H G

1996-01-01

105

Optimal bearing surfaces for total hip replacement in the young patient: a meta-analysis  

Microsoft Academic Search

Although there is general consensus about the efficacy of total hip replacement (THR) in young patients, the most appropriate\\u000a bearings in young patients remain highly debated. The three most popular bearings in use include metal-on-polyethylene (MOP),\\u000a metal-on-metal (MOM) and ceramic-on-ceramic (COC). We conducted a systematic review and meta-analysis of literature to summarise\\u000a the best available evidence on relative success of

Vijay Shetty; Bhushan Shitole; Gautam Shetty; Harshad Thakur; Mohit Bhandari

106

Metal-on-Metal Hip Systems  

Center for Biologics Evaluation and Research (CBER)

Text Version... Post-operative leg length inequality • Dislocation of the head from the socket • Post-operative nerve palsy • Implant wear • Prosthesis loosening ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

107

The complete mitochondrial genome of the large-headed frog, Limnonectes bannaensis (Amphibia: Anura), and a novel gene organization in the vertebrate mtDNA.  

PubMed

We determined the complete nucleotide sequence of the mitochondrial (mt) genome of the large-headed frog, Limnonectes bannaensis (Amphibia, Anura) by using polymerase chain reaction (PCR). The entire mtDNA sequence is 16,867 bp in length with a novel case of tRNAs in vertebrates. This mt genome is characterized by three distinctive features: (1) a tandem duplication of tRNA(Met) gene is observed, (2) the tRNA(Ala), tRNA(Asn), tRNA(Cys) and tRNA(Glu) genes coded on the L-strand are absent from the L. bannaensis mtDNA, the tRNA(Cys) and tRNA(Glu) genes change into tRNA pseudogenes by reason of degenerative anticodon, and a noncoding sequence of 206 nt long (NC1) has replaced the original position of other two tRNAs, (3) besides NC1, another three noncoding spacers (NC2-4) longer than 50 bp are found in the broken WANCY region and the region NC3-ND5-NC4-ND6-PsiE-Cytb-CR of the new sequence. These features could be explained by a model of gene duplication and deletion. The new sequence data was used to assess the phylogenetic relationships among 25 species of Anura using neighbor-joining, Bayesian, and maximum likelihood methods, and the phylogenetic tree shows the rice frog Fejervarya limnocharis is closest to L. bannaensis in the study. PMID:19397958

Zhang, Ji-Feng; Nie, Liu-Wang; Wang, Yang; Hu, Li-Li

2009-05-03

108

Alternative bearing surfaces in total hip arthroplasty.  

PubMed

Polyethylene wear and extension of indications of total hip arthroplasty into younger and younger age groups have pushed manufacturers to develop more durable bearing surfaces. Standard polyethylene, the plastic used for the first 3 decades of hip replacement, virtually ceases to exist in its original form. Modifications of the processing, including sterlization in an inert environment and cross-linking, have demonstrated some improvements in wear. Hard-on-hard bearings such as ceramic-on-ceramic and metal-on-metal also have demonstrated extremely low wear. This article reviews the pros and cons of the alternative bearing options available to assist in the proper bearing selection for a particular patient. PMID:12882250

Inzerillo, V Christopher; Garino, Jonathan P

2003-01-01

109

Clinical wear behaviour of ultra-high molecular weight polyethylene cups paired with metal and ceramic ball heads in comparison to metal-on-metal pairings of hip joint replacements.  

PubMed

In the course of 30 years of hip endoprosthetics, a number of material combinations for the cups and balls of total hip prostheses have proven successful under clinical conditions. Favourably priced hip prostheses with polyethylene cups and metal balls are available for older patients with a moderate range of activity. Polyethylene wear of 100-300 microns/year is to be expected with these models. Ceramic balls (aluminium oxide for diameters 32 and 28 mm and zirconium oxide for 22 mm) paired with polyethylene cups are recommended for patients with a life expectancy of 10 to 20 years, because the expected polyethylene wear rate with this material combination is only 50-150 microns/year. In other words, the life cycle of the polyethylene cup is doubled, when it is paired with a ceramic ball. A similar polyethylene wear rate is also to be expected with oxygen-deep-hardened TiAlNb metal balls, which are currently the subject of a clinical field study. Last but not least, CoCrMoC metal-metal and Al2O3 ceramic ceramic pairings, which have the lowest wear rate of 2-20 microns/year, are available for highly active patients with a life expectancy of more than 20 years. As far as the cup-ball pairing is concerned and under the current pressure of costs, the surgeon should be able to select the optimum hip prosthesis model for every patient from these three categories. PMID:9141893

Semlitsch, M; Willert, H G

1997-01-01

110

Metal on Metal in Resurfacing Arthroplasty: Risks or Benefits?  

Microsoft Academic Search

\\u000a At the beginning of hip endoprosthetics was the substitution of destroyed cartilage by biologigal or artificial materials.\\u000a However, successful results were only achieved after the introduction of abrasion-resistant materials in combination with\\u000a exactly matching differences of diameter (radial clearance) of head and socket. The cobalt-based alloy Vitalliun® which had\\u000a been introduced into medical therapy by dentists in 1932 was used

M. Menge

111

Types of Metal-on-Metal Hip Systems  

Center for Biologics Evaluation and Research (CBER)

Text Version... No. All artificial hips require one component to slide against ... is based on a risk-benefit ratio with ... been shown to provide significant benefits (eg, high ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

112

Fracture of the modular femoral neck component in total hip arthroplasty.  

PubMed

The use of modularity, specifically dual modular femoral stems, in total hip arthroplasty has increased in popularity over the past 2 decades. While offering several distinct advantages intraoperatively, the long-term success of adding a second modular junction has yet to be established. One potential complication of increasing modularity is component fracture. We present a case of modular femoral neck prosthesis fracture necessitating revision surgery to treat this complication. Careful preoperative planning during revision of these failures is essential to avoid morbidity and unnecessary subsequent revision surgeries, as demonstrated in this case. The combined effects of crevice and fretting corrosion, large-diameter femoral head, long modular neck, metal-on-metal articulation, patient size, and activity level may have all played integral roles in creating an environment susceptible to this classic pattern of fatigue fracture. PMID:21798696

Ellman, Michael B; Levine, Brett R

2011-07-27

113

Accelerating failure rate of the ASR total hip replacement.  

PubMed

There is widespread concern regarding the incidence of adverse soft-tissue reactions after metal-on-metal (MoM) hip replacement. Recent National Joint Registry data have shown clear differences in the rates of failure of different designs of hip resurfacing. Our aim was to update the failure rates related to metal debris for the Articular Surface Replacement (ASR). A total of 505 of these were implanted. Kaplan-Meier analysis showed a failure rate of 25% at six years for the ASR resurfacing and of 48.8% for the ASR total hip replacement (THR). Of 257 patients with a minimum follow-up of two years, 67 (26.1%) had a serum cobalt concentration which was greater than 7 ?g/l. Co-ordinate measuring machine analysis of revised components showed that all patients suffering adverse tissue reactions in the resurfacing group had abnormal wear of the bearing surfaces. Six THR patients had relatively low rates of articular wear, but were found to have considerable damage at the trunion-taper interface. Our results suggest that wear at the modular junction is an important factor in the development of adverse tissue reactions after implantation of a large-diameter MoM THR. PMID:21768621

Langton, D J; Jameson, S S; Joyce, T J; Gandhi, J N; Sidaginamale, R; Mereddy, P; Lord, J; Nargol, A V F

2011-08-01

114

Metallosis due to impingement between the socket and the femoral head in a total hip prosthesis. A case report.  

PubMed

Metallosis is usually defined as aseptic fibrosis, local necrosis, or loosening of a device secondary to metallic corrosion and release of wear debris. It is an occasional but characteristic clinical finding in patients who have a metal-on-metal design of total hip replacement, or when metal surfaces contact after a failure or erosion of the polyethylene component. We report the case of a patient who had severe metallosis caused by wear of the femoral head with the titanium socket, after the complete erosion and destruction of the polyethylene cup, with failure of the accetabular component. Breakage of the acetabular cup constitutes one of the possible long-term complications occurring as a result of a total hip replacement. This extremely rare complication can occur at any time postoperatively and may not be associated with symptoms or other problems for a long time. PMID:12643077

Gambera, Dario; Carta, Serafino; Crainz, Edoardo; Fortina, Mattia; Maniscalco, Pietro; Ferrata, Paolo

2002-01-01

115

Totally James  

ERIC Educational Resources Information Center

|This article presents an interview with James Howe, author of "The Misfits" and "Totally Joe". In this interview, Howe discusses tolerance, diversity and the parallels between his own life and his literature. Howe's four books in addition to "The Misfits" and "Totally Joe" and his list of recommended books with lesbian, gay, bisexual,…

Owens, Tom

2006-01-01

116

Totally James  

ERIC Educational Resources Information Center

This article presents an interview with James Howe, author of "The Misfits" and "Totally Joe". In this interview, Howe discusses tolerance, diversity and the parallels between his own life and his literature. Howe's four books in addition to "The Misfits" and "Totally Joe" and his list of recommended books with lesbian, gay, bisexual, transgender,…

Owens, Tom

2006-01-01

117

Total glossectomy.  

PubMed

Forty-five patients had a "total" glossectomy for initial advanced tongue carcinoma or for recurrent carcinoma. Forty percent of the patients (18) had a total laryngectomy at the time of glossectomy. Forty-nine percent of the patients (22) had either a lateral or anterior mandibulectomy at the time of glossectomy. Seventy-one percent of the patients (15 of 21) who had an intact larynx and 12.5 percent who had laryngectomy (3 of 24) had some degree of useful speech. Thirty-one percent of the patients (14 of 45) had no problems in deglutition whereas 53 percent of the patients (24) needed a nasogastric tube, 4 patients inserted the feeding tube themselves, 2 had a cervical esophagostomy, and 1 had a special prosthesis for feeding purposes. Thirty-seven percent of the patients (10 of 27) had considerable aspiration problems. Twenty-two percent (6 patients) needed a laryngectomy, and 7.5 percent (2 patients) needed a cervical esophagostomy to prevent further problems. Seven and one-half percent of the patients (2) succumbed to serious pulmonary infection. In this study, total glossectomy had a salvage rate of 65 percent at 6 months postoperatively, 27.5 percent at 1 year, 25 percent at 2 years, 25 percent at 3 years, 20 percent at 5 years, and 10 percent at 10 years. PMID:6625097

Razack, M S; Sako, K; Bakamjian, V Y; Shedd, D P

1983-10-01

118

Polyethylene Wear in Retrieved Reverse Total Shoulder Components  

PubMed Central

Background Reverse total shoulder arthroplasty has been used to treat rotator cuff tear arthropathy, proximal humeral fractures and for failed conventional total shoulder prostheses. It has been suggested that polyethylene wear is potentially higher in reverse shoulder replacements than in conventional shoulder replacements. The modes and degree of polyethylene wear have not been completely elucidated. The purpose of this study was to evaluate polyethylene wear patterns in seven specimens retrieved at revision arthroplasty and identify factors that may be associated with increased wear. Methods Reverse total shoulder components were retrieved from 7 patients during revision arthroplasty for loosening and/or pain. Pre-operative glenoid tilt and placement, and scapular notching were evaluated using pre-operative radiographs. Polyethylene wear was evaluated using microCT and optical microscopy. Results Wear on the rim of the polyethylene humeral cup, was identified on all retrieved components. The extent of rim wear varied from a penetration depth of 0.1 to 4.7 mm. We could not demonstrate a correlation between scapular notching and rim wear. However, rim wear was more extensive when the inferior screw had made contact with the liner. Metal on metal wear between the humeral component and the inferior screw of one component was also observed. Wear of the intended bearing surface was minimal. Discussion Rim damage was the predominant cause of polyethylene wear in our retrieved specimens. Direct contact between the humeral component and inferior metaglene screws is concerning because this could lead to accelerated UHMWPE wear and also induce mechanical loosening of the glenoid component.

Day, Judd S; MacDonald, Daniel W; Olsen, Madeline; Getz, Charles; Williams, Gerald R; Kurtz, Steven M

2011-01-01

119

Cost-effectiveness of total hip arthroplasty versus resurfacing arthroplasty: economic evaluation alongside a clinical trial  

PubMed Central

Objective To report on the relative cost-effectiveness of total hip arthroplasty and resurfacing arthroplasty (replacement of articular surface of femoral head only) in patients with severe arthritis suitable for hip joint resurfacing arthroplasty. Design Cost-effectiveness analysis on an intention-to-treat basis of a single-centre, single-blind randomised controlled trial of 126 adult patients within 12?months of treatment. Missing data were imputed using multiple imputations with differences in baseline quality of life and gender adjusted using regression techniques. Setting A large teaching hospital trust in the UK. Participants A total of 126 adult patients with severe arthritis of the hip joint suitable for a resurfacing arthroplasty of the hip. Results Data were received for 126 patients, 4 of whom did not provide any resource use data. For the remainder, data were imputed for costs or quality of life in at least one time point (baseline, 3, 6?months and 1?year) for 18 patients. Patients in the resurfacing arm had higher quality of life at 12?months (0.795 vs 0.727) and received 0.032 more QALYs within the first 12?months postoperation. At an additional cost of £564, resurfacing arthroplasty offers benefits at £17?451 per QALY within the first 12?months of treatment. When covariates are considered, the health economic case is stronger in men than in women. Conclusions Resurfacing arthroplasty appears to offer very short-term efficiency benefits over total hip arthroplasty within a selected patient group. The short-term follow-up in this trial should be noted, particularly in light of the concerns raised regarding adverse reactions to metal debris from metal-on-metal bearing surfaces in the longer term. Longer-term follow-up of resurfacing arthroplasty patients and decision analytic modelling is also advised. Trial registration Current controlled Trials ISRCTN33354155. UKCRN 4093.

Edlin, Richard; Tubeuf, Sandy; Achten, Juul; Parsons, Nicholas; Costa, Matthew

2012-01-01

120

New insights into hard phases of CoCrMo metal-on-metal hip replacements.  

PubMed

The microstructural and mechanical properties of the hard phases in CoCrMo prosthetic alloys in both cast and wrought conditions were examined using transmission electron microscopy and nanoindentation. Besides the known carbides of M(23)C(6)-type (M=Cr, Mo, Co) and M(6)C-type which are formed by either eutectic solidification or precipitation, a new mixed-phase hard constituent has been found in the cast alloys, which is composed of ?100 nm fine grains. The nanosized grains were identified to be mostly of M(23)C(6) type using nano-beam precession electron diffraction, and the chemical composition varied from grain to grain being either Cr- or Co-rich. In contrast, the carbides within the wrought alloy having the same M(23)C(6) structure were homogeneous, which can be attributed to the repeated heating and deformation steps. Nanoindentation measurements showed that the hardness of the hard phase mixture in the cast specimen was ?15.7 GPa, while the M(23)C(6) carbides in the wrought alloy were twice as hard (?30.7 GPa). The origin of the nanostructured hard phase mixture was found to be related to slow cooling during casting. Mixed hard phases were produced at a cooling rate of 0.2 °C/s, whereas single phase carbides were formed at a cooling rate of 50 °C/s. This is consistent with sluggish kinetics and rationalizes different and partly conflicting microstructural results in the literature, and could be a source of variations in the performance of prosthetic devices in-vivo. PMID:22659365

Liao, Y; Pourzal, R; Stemmer, P; Wimmer, M A; Jacobs, J J; Fischer, A; Marks, L D

2012-03-28

121

New Insights into Hard Phases of CoCrMo Metal-on-Metal Hip Replacements  

PubMed Central

The microstructural and mechanical properties of the hard phases in CoCrMo prosthetic alloys in both cast and wrought conditions were examined using transmission electron microscopy and nanoindentation. Besides the known carbides of M23C6-type (M=Cr, Mo, Co) and M6C-type which are formed by either eutectic solidification or precipitation, a new mixed-phase hard constituent has been found in the cast alloys, which is composed of ~100 nm fine grains. The nanosized grains were identified to be mostly of M23C6 type using nano-beam precession electron diffraction, and the chemical composition varied from grain to grain being either Cr- or Co-rich. In contrast, the carbides within the wrought alloy having the same M23C6 structure were homogeneous, which can be attributed to the repeated heating and deformation steps. Nanoindentation measurements showed that the hardness of the hard phase mixture in the cast specimen was ~15.7 GPa, while the M23C6 carbides in the wrought alloy were twice as hard (~30.7 GPa). The origin of the nanostructured hard phase mixture was found to be related to slow cooling during casting. Mixed hard phases were produced at a cooling rate of 0.2 °C/s, whereas single phase carbides were formed at a cooling rate of 50 °C/s. This is consistent with sluggish kinetics and rationalizes different and partly conflicting microstructural results in the literature, and could be a source of variations in the performance of prosthetic devices in-vivo.

Liao, Y.; Pourzal, R.; Stemmer, P.; Wimmer, M.A.; Jacobs, J.J.; Fischer, A.; Marks, L. D.

2012-01-01

122

Cementing the metaphyseal stem in metal-on-metal resurfacing: when and why.  

PubMed

Initial fixation of the femoral component in hip resurfacing is key to the enduring survival of the prosthesis. Cementing the metaphyseal stem increases the interface area between bone and cement. We compared the clinical and survivorship results of two groups in a cohort of 1000 hips (838 patients) implanted with Conserve((R)) Plus hip resurfacing; one group was resurfaced with a cemented metaphyseal stem (400 hips; Group 1) and the other with a press-fit stem (600 hips; Group 2). We carried out a time-dependent analysis to determine the indications for cementing the stem. The 5-year Kaplan-Meier survival estimate was 98.2% for Group 1 and 94.4% for Group 2, using any revision as an endpoint. Femoral aseptic failure was reduced in Group 1 compared to Group 2. Cementing the metaphyseal stem is particularly effective for hips with a small femoral component size (< 48 mm) and hips with large femoral defects (> 1 cm). There was no difference between groups in incidence of femoral neck narrowing or femoral neck fractures. Longer followup is needed to determine if cementing the stem can be detrimental to the long-term durability of the femoral implant. Level of Evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. PMID:18972179

Amstutz, Harlan C; Le Duff, Michel J

2008-10-30

123

Metal on metal oxide nanowire Co-catalyzed Si photocathode for solar water splitting.  

PubMed

We report a systematic study of Si|ZnO and Si|ZnO| metal photocathodes for effective photoelectrochemical cells and hydrogen generation. Both ZnO nanocrystalline thin films and vertical nanowire arrays were studied. Si|ZnO electrodes showed increased cathodic photocurrents due to improved charge separation by the formation of a p/n junction, and Si|ZnO:Al (n(+)-ZnO) and Si|ZnO(N(2)) (thin films prepared in N(2)/Ar gas) lead to a further increase in cathodic photocurrents. Si|ZnONW (nanowire array) photocathodes dramatically increased the photocurrents and thus photoelectrochemical conversion efficiency due to the enhanced light absorption and enlarged surface area. The ZnO film thickness and ZnO nanowire length were important to the enhancements. A thin metal coating on ZnO showed increased photocurrent due to a catalyzed hydrogen evolution reaction and Ni metal showed comparable catalytic activities to those of Pt and Pd. Moreover, photoelectrochemical instability of Si|ZnO electrodes was minimized by metal co-catalysts. Our results indicate that the metal and ZnO on p-type Si serve as co-catalysts for photoelectrochemical water splitting, which can provide a possible low-cost and scalable method to fabricate high efficiency photocathodes for practical applications in clean solar energy harvesting. PMID:22539234

Sun, Ke; Madsen, Kristian; Andersen, Pål; Bao, Weining; Sun, Zhelin; Wang, Deli

2012-04-27

124

Total hip arthroplasty in the young: special emphasis on post-SCFE patients.  

PubMed

Slipped capital femoral epiphysis (SCFE) is a hip disorder of adolescence, which has the potential for profound implications into adulthood. SCFE patients are at risk of early joint degeneration and subsequent need for arthroplasty. The rate at which arthroplasty is required is not precisely known, but is estimated to be approximately 45% by 50 years after a slip. The femoral neck and shaft displace anteriorly and rotate externally relative to the femoral epiphysis, which remains fixed in the acetabulum. Stabilization of the physis is the goal of acute management. Despite such efforts, accelerated joint degeneration may occur over time. This progression is due to avascular necrosis, chondrolysis, or following years of femoroacetabular impingement. Total hip arthroplasty (THA) and total hip resurfacing (THR) are options for end-stage hip arthritis due to SCFE. THR is technically more challenging, with very limited ability to address deformity-related issues of impingement, decreased hip offset, and trochanteric malposition. THR, as in any metal on metal arthroplasty, may be associated with local metal sensitivity or systemic metal toxicity. Given the limited utility and potential risks, THR is currently not recommended in the majority of cases. THA, although historically demonstrating poor long-term implant performance in the young patient, has become a more reliable option recently. The potential benefits of THA are considerable, even for the young patient with end-stage hip degeneration. Certain cemented and many cementless stem designs show good long-term survival, as do current cementless cups. Advances in bearing surfaces promise to minimize wear and extend implant longevity. Ceramic on ceramic, metal on highly cross-linked polyethylene, and ceramic on highly cross-linked polyethylene bearing couples offer promise. PMID:23764787

Nelms, Nathaniel J; Lewallen, Laura W; McIntosh, Amy L; Sierra, Rafael J

125

Ceramic-on-metal bearings in total hip replacement: whole blood metal ion levels and analysis of retrieved components.  

PubMed

This study reports on ceramic-on-metal (CoM) bearings in total hip replacement. Whole blood metal ion levels were measured. The median increase in chromium and cobalt at 12 months was 0.08 microg/1 and 0.22 microg/1, respectively, in CoM bearings. Comparable values for metal-on-metal (MoM) were 0.48 microg/1 and 0.32 microg/1. The chromium levels were significantly lower in CoM than in MoM bearings (p = 0.02). The cobalt levels were lower, but the difference was not significant. Examination of two explanted ceramic heads revealed areas of thin metal transfer. CoM bearings (one explanted head and acetabular component, one explanted head and new acetabular component, and three new heads and acetabular components) were tested in a hip joint simulator. The explanted head and acetabular component had higher bedding-in. However, after one million cycles all the wear rates were the same and an order of magnitude less than that reported for MoM bearings. There were four outliers in each clinical group, primarily related to component malposition. PMID:19721036

Isaac, G H; Brockett, C; Breckon, A; van der Jagt, D; Williams, S; Hardaker, C; Fisher, J; Schepers, A

2009-09-01

126

Enhanced wear and corrosion in modular tapers in total hip replacement is associated with the contact area and surface topography.  

PubMed

Widespread concern exists about adverse tissue reactions after metal-on-metal (MoM) total hip replacement (THR). Concerns have also been expressed with wear and corrosion of taper junctions in THR. We report the effect of surface finish and contact area associated with a single combination of materials of modular tapers. In an in vitro test, we investigated the head/neck (CoCrMo/Ti) interface of modular THRs using commercially available heads. Wear and corrosion of taper surfaces was compared following a 10 million loading cycle. Surface parameters and profiles were measured before and after testing. Electrochemical static and dynamic corrosion tests were performed under loaded and non-loaded conditions. After the load test, the surface roughness parameters on the head taper were significantly increased where the head/neck contact area was reduced. Similarly, the surface roughness parameters on the head taper were significantly increased where rough neck tapers were used. Corrosion testing showed breaching of the passive film on the rough but not the smooth neck tapers. Thus, surface area and surface finish are important factors in wear and corrosion at modular interfaces. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:2032-2039, 2013. PMID:23966288

Panagiotidou, Anna; Meswania, Jay; Hua, Jia; Muirhead-Allwood, Sarah; Hart, Alister; Blunn, Gordon

2013-08-21

127

Nanotoxicology of metal wear particles in total joint arthroplasty: a review of current concepts.  

PubMed

Metal-on-metal (M-M) joint replacement has raised concerns about the long-term effects of metal wear debris and corrosion products. This review summarizes the current concepts in biological reactivity to metal wear particles, ions, and corrosion products. Attention is focused on Co-Cr-Mo alloy since it is the most diffused and discussed material in arthroplasty. PMID:20740415

Billi, Fabrizio; Campbell, Pat

128

Factors correlating with long term survival of McKee-Farrar total hip prostheses.  

PubMed

Clinical and radiographic evaluations of 15 McKee-Farrar hip replacements in 13 patients with followup of 21 to 26 years were performed. The average Harris hip score was 86 with no patients having a poor result. These patients outscored the age matched controls in all categories of the SF-36 health survey. All patients were community ambulators with qualitative activity levels exceeding the average for their age. Quantitative activity assessment with a pedometer in 3 patients indicated a current average of approximately 900,000 cycles per year. This represents more than 21 million cycles when extrapolated during the life of the implants. None of the femoral components were radiographically loose. One acetabular component may be loose. Osteolysis developed in 3 apparently well fixed femurs and in 1 acetabulum. There were several features of these cases that may have contributed to the long survival: (1) relatively small stature of the patients who averaged 160.5 cm (5 feet 5 inches) in height and 66.9 kg (147 lbs) in weight; (2) favorable biomechanics of the reconstruction with the hip center of rotation being medialized by an average of 6.4 mm and the femoral offset increased by an average of 4.9 mm; (3) decreased potential for neck socket impingement with an average lateral acetabular opening of 54 degrees and all components were anteverted; (4) radiolucent cement in 13 of 15 hips; and (5) no radiographically measurable wear. Previous analyses and comparisons of the clinical performance of the McKee-Farrar implant have focused on the metal on metal bearing. As has been recognized with the many variations of total hip replacement using metal on plastic hearings, there are a myriad of variables that contribute to clinical outcome. The results of this study suggest that patient selection and technical factors may contribute to the long term survival, and conversely to the failure, of McKee-Farrar implants. PMID:8769322

Schmalzried, T P; Szuszczewicz, E S; Akizuki, K H; Petersen, T D; Amstutz, H C

1996-08-01

129

Estonian total ozone climatology  

NASA Astrophysics Data System (ADS)

The climatological characteristics of total ozone over Estonia based on the Total Ozone Mapping Spectrometer (TOMS) data are discussed. The mean annual cycle during 1979 2000 for the site at 58.3° N and 26.5° E is compiled. The available ground-level data interpolated before TOMS, have been used for trend detection. During the last two decades, the quasi-biennial oscillation (QBO) corrected systematic decrease of total ozone from February April was 3 +/- 2.6% per decade. Before 1980, a spring decrease was not detectable. No decreasing trend was found in either the late autumn ozone minimum or in the summer total ozone. The QBO related signal in the spring total ozone has an amplitude of +/- 20 DU and phase lag of 20 months. Between 1987 1992, the lagged covariance between the Singapore wind and the studied total ozone was weak. The spring (April May) and summer (June August) total ozone have the best correlation (coefficient 0.7) in the yearly cycle. The correlation between the May and August total ozone is higher than the one between the other summer months. Seasonal power spectra of the total ozone variance show preferred periods with an over 95% significance level. Since 1986, during the winter/spring, the contribution period of 32 days prevails instead of the earlier dominating 26 days. The spectral densities of the periods from 4 days to 2 weeks exhibit high interannual variability.

Eerme, K.; Veismann, U.; Koppel, R.

2002-02-01

130

Totally transrectal endoscopic total mesorectal excision (TME).  

PubMed

Surgical treatment has been in constant evolution in the search for minimizing incisions regardless of the complexity of the operation. Natural Orifice Translumenal Endoscopic Surgery (NOTES) represents this progression of surgery to less invasive procedures. Transanal endoscopic microsurgery (TEM) is an ideal NOTES platform to access the peritoneal cavity endoscopically through the anus and specifically to allow colorectal resections be performed through smaller, or indeed without, abdominal incisions. Transanal rectosigmoidectomy with total mesorectal excision (TME) using TEM is a feasible and oncologically safe option. Such use of currently available combined hybrid laparoendoscopic systems provides a safe platform to define future clinical applications and advantages of NOTES. Furthermore, it stimulates the active development of technologies that will support and enable it. PMID:22098517

Lacy, A M; Adelsdorfer, C

2011-11-01

131

Total Baseball Online  

NSDL National Science Digital Library

Total Baseball Online, provided by Tot@l Sports, is a web version of the well known Total Baseball encyclopedia. The highlight of the site is the availability of complete statistics (in a searchable database) of every major league player. Total Baseball not only gives players' raw statistics, but also its own set of derived statistics, including such variables as "Production Plus," "Park Factor," "Runs Created," and "Total Pitcher Index," among many others, all explained at the site and guaranteed to produce arguments among fans. There are also biographies, history, features, records, and a chat room--a veritable mountain of virtual information. At this time, there is no section on the World Series available. Total Baseball Online is only viewable with a browser that supports frames.

132

Total hip arthroplasty.  

PubMed Central

Total hip arthroplasty, or surgical replacement of the hip joint with an artificial prosthesis, is a reconstructive procedure that has improved the management of those diseases of the hip joint that have responded poorly to conventional medical therapy. In this review we briefly summarize the evolution of total hip arthroplasty, the design and development of prosthetic hip components, and the current clinical indications for this procedure. The possible complications of total hip arthroplasty, its clinical performance over time, and future directions in hip replacement surgery are also discussed. Images

Siopack, J S; Jergesen, H E

1995-01-01

133

Totally Confined Explosive Welding.  

National Technical Information Service (NTIS)

A method is described for eliminating the noise and debris of explosive welding techniques by totally enclosing and applying the explosive pressure through the wall of an enclosure. This method eliminates the problem of scattering debris, and personnel ha...

L. J. Bement

1973-01-01

134

Total Water Management.  

National Technical Information Service (NTIS)

There is a growing need for urban water managers to take a more holistic view of their water resource systems as population growth, urbanization, and current o perations put different stresses on the environment and urban infrastructure. Total Water Manag...

A. Cannan D. Rodrigo E. J. L. Calva L. Roesner

2012-01-01

135

Measurements of total ozone.  

National Technical Information Service (NTIS)

The renewed concern about the ozone layer initiated a project of monitoring the total ozone in 1987. A Brewer ozone spectrophotometer at the Swedish Meteorological and Hydrological Institute (SMHI) in Norrkoeping and previously used for solar ultraviolet ...

W. Josefsson

1993-01-01

136

Total Water Management - slides  

EPA Science Inventory

Total Water Management (TWM) examines urban water systems in an interconnected manner. It encompasses reducing water demands, increasing water recycling and reuse, creating water supply assets from stormwater management, matching water quality to end-use needs, and achieving envi...

137

Total Diet Study - References  

Center for Food Safety and Applied Nutrition (CFSAN)

... US Food and Drug Administration's Total Diet Study: Intake of Nutritional and Toxic Elements, 1991-96. Food Addit. Contam. 19(2):103-125. ... More results from www.fda.gov/food/foodscienceresearch/totaldietstudy

138

Total Photon Absorption.  

National Technical Information Service (NTIS)

The present discussion is limited to a presentation of the most recent total photonuclear absorption experiments performed with real photons at intermediate energy, and more precisely in the region of nucleon resonances. The main sources of real photons a...

P. Carlos

1985-01-01

139

Totally Parallel Multilevel Algorithms.  

National Technical Information Service (NTIS)

Four totally parallel algorithms for the solution of a sparse linear system have common characteristics which become quite apparent when they are implemented on a highly parallel hypercube such as the CM2. These four algorithms are Parallel Superconvergen...

P. O. Frederickson

1988-01-01

140

Total lymphoid irradiation  

SciTech Connect

Total lymphoid irradiation by itself can produce sufficient immunosuppression to prolong the survival of a variety of organ allografts in experimental animals. The degree of prolongation is dose-dependent and is limited by the toxicity that occurs with higher doses. Total lymphoid irradiation is more effective before transplantation than after, but when used after transplantation can be combined with pharmacologic immunosuppression to achieve a positive effect. In some animal models, total lymphoid irradiation induces an environment in which fully allogeneic bone marrow will engraft and induce permanent chimerism in the recipients who are then tolerant to organ allografts from the donor strain. If total lymphoid irradiation is ever to have clinical applicability on a large scale, it would seem that it would have to be under circumstances in which tolerance can be induced. However, in some animal models graft-versus-host disease occurs following bone marrow transplantation, and methods to obviate its occurrence probably will be needed if this approach is to be applied clinically. In recent years, patient and graft survival rates in renal allograft recipients treated with conventional immunosuppression have improved considerably, and thus the impetus to utilize total lymphoid irradiation for its immunosuppressive effect alone is less compelling. The future of total lymphoid irradiation probably lies in devising protocols in which maintenance immunosuppression can be eliminated, or nearly eliminated, altogether. Such protocols are effective in rodents. Whether they can be applied to clinical transplantation remains to be seen.

Sutherland, D.E.; Ferguson, R.M.; Simmons, R.L.; Kim, T.H.; Slavin, S.; Najarian, J.S.

1983-05-01

141

Head size and dislocation rate in primary total hip arthroplasty  

PubMed Central

Background: Dislocation after total hip arthroplasty (THA) has a multifactorial etiology with variables such as surgical approach, component orientation and position, type of cup, stem and head size. Review of the literature regarding the relationship of head size and dislocation rate in THA is suggestive that large femoral head size is associated with lower dislocation rate after THA. However, limited data is available as a proof of this hypothesis. The purpose of this study was to determine that the use of large head size would lead to a decreased incidence of dislocations following THA. Materials and Methods: 317 primary THAs were performed using the posterolateral approach with posterior soft-tissue repair between January 2006 and December 2009. Cases were divided into two groups (A and B). Femoral head diameter size 36 mm was used in 163 THA in group A and 28 mm in 154 THA in group B. Average period of followup being 2 years (6 month to 4 years). Patients were routinely followed at definite intervals and were specifically assessed for dislocation. Results: One or more dislocations occurred in 11 out of 317 hips with the overall rate of dislocation being 3.47%. Dislocation rate was 0.6% in 36 mm head size and 6.49% with 28 mm head size (P value is 0.0107). Keeping the stem design variable as a constant, the difference in the rate of dislocation between the two groups was again found to be statistically significant for both un-cemented and cemented stem. Conclusion: Dislocation rate decreased significantly as the size of the head increased in primary THA. However, longer followup is necessary as rate of dislocation or in vivo highly cross linked poly failure or fracture may increase in future affecting the rate of dislocations in primary THA.

Singh, Somesh P; Bhalodiya, Haresh P

2013-01-01

142

Total Energy Monitor  

SciTech Connect

The total energy monitor (TE) is a thermal sensor that determines the total energy of each FEL pulse based on the temperature rise induced in a silicon wafer upon absorption of the FEL. The TE provides a destructive measurement of the FEL pulse energy in real-time on a pulse-by-pulse basis. As a thermal detector, the TE is expected to suffer least from ultra-fast non-linear effects and to be easy to calibrate. It will therefore primarily be used to cross-calibrate other detectors such as the Gas Detector or the Direct Imager during LCLS commissioning. This document describes the design of the TE and summarizes the considerations and calculations that have led to it. This document summarizes the physics behind the operation of the Total Energy Monitor at LCLS and derives associated engineering specifications.

Friedrich, S

2008-08-11

143

Total Quality Management (TQM).  

National Technical Information Service (NTIS)

The purpose of this paper is four folded: (1) to provide a follow-up report to the article 'Implementating Total Quality Management (TQM) at Pearl Harbor Naval Shipyard' published in 1988; (2) to document Pearl Harbor Naval Shipyard's TQM strategies after...

G. A. Damon

1989-01-01

144

Total “internal” hemipelvectomy  

Microsoft Academic Search

Several authors have described resections of tumorbearing parts of the pelvis including reconstructive plastic surgery. With extensive tumor growth present mutilating hemipelvectomies often have been the last resort. Even the most sophisticated prostheses hardly ever enabled the patients to walk again. We have therefore performed total “internal” hemipelvectomies in three cases. The necessary substitute consisted of half a pelvis made

C. Burri; L. Claes; H. Gerngroß; R. Mathys

1979-01-01

145

MINIMIZING TOTAL VARIATION FLOW  

Microsoft Academic Search

We prove existence and uniqueness of weak solutions for the minimizing total variation ?ow with initial data in L1. We prove that the length of the level sets of the solution, i.e., the boundaries of the level sets, decreases with time, as one would expect, and the solution converges to the spatial average of the initial datum as t !1

F. Andreu; C. Ballester; V. Caselles; J. M. Mazon

1998-01-01

146

Total hip replacement arthroplasty  

Microsoft Academic Search

A prospective study of 62 total hip replacements performed between February 1970 and December 1972 in 50 patients was carried out. The results were assessed according to the Asaf Harofe Hip Evaluation System. There were excellent and good results in 89% of hips. Failures occured in 11% and were due to individual cases of loosening of the femoral component, loosening

D. H. Gershuni; A. Axer; D. Segal; N. Halperin

1974-01-01

147

Laparoscopic total abdominal colectomy  

Microsoft Academic Search

The aim of this study was to prospectively assess the impact of laparoscopy upon the outcome of total abdominal colectomy (TAC). Specifically, patients underwent standard laparotomy with TAC and ileoproctostomy (TAC + IP), TAC and ileoanal reservoir (TAC + IAR), laparoscopically assisted TAC + IP (L-TAC + IP), or laparoscopically assisted TAC + IAR (L-TAC + IAR). Parameters studied included

Steven D. Wexner; Olaf B. Johansen; Juan J. Nogueras; David G. Jagelman

1992-01-01

148

Total Energy CMR Production.  

National Technical Information Service (NTIS)

The following outlines the optimized pulsed laser deposition (PLD) procedure used to prepare Nd(sub 0.67)Sr(sub 0.33)MnO(sub 3) (NSMO) temperature sensors at Towson University (Prof. Rajeswari Kolagani) for the LCLS XTOD Total Energy Monitor. The samples ...

R. M. Kolagani S. Friedrich

2008-01-01

149

Total Variation in Imaging  

Microsoft Academic Search

The use of total variation as a regularization term in imaging problems was motivated by its ability to recover the image discontinuities. This is at the basis of his numerous applications to denoising, optical flow, stereo imaging and 3D surface reconstruction, segmentation, or interpolation, to mention some of them. On one hand, we review here the main theoretical arguments that

V. Caselles; A. Chambolle; M. Novaga

150

Total Quality Management Simplified.  

ERIC Educational Resources Information Center

|Maintains that Total Quality Management (TQM) is one method that helps to monitor and improve the quality of child care. Lists four steps for a child-care center to design and implement its own TQM program. Suggests that quality assurance in child-care settings is an ongoing process, and that TQM programs help in providing consistent,…

Arias, Pam

1995-01-01

151

Total Quality Management Seminar.  

ERIC Educational Resources Information Center

|This booklet is one of six texts from a workplace literacy curriculum designed to assist learners in facing the increased demands of the workplace. The booklet contains seven sections that cover the following topics: (1) meaning of total quality management (TQM); (2) the customer; (3) the organization's culture; (4) comparison of management…

Massachusetts Career Development Inst., Springfield.

152

A Total Solar Eclipse  

NSDL National Science Digital Library

The representation depicts a total solar eclipse with a static diagram showing the moon positioned between the sun and Earth. The point where the shadow cone reaches the Earth is labeled with an arrow stating it as the "eclipse path." The umbra and penumbra are also labeled.

153

Total synthesis of (-)-histrionicotoxin.  

PubMed

A total synthesis of (-)-histrionicotoxin was achieved. Our synthesis features preparation of a pseudosymmetrical dienyne through chirality transfer from an allenylsilane, a dienyne metathesis to produce the bicyclo [5.4.0] system in optically active form, selective functionalization of a diene via a 5-exo-trig iodoetherification, and an asymmetric propargylation. PMID:21793562

Adachi, Yohei; Kamei, Noriyuki; Yokoshima, Satoshi; Fukuyama, Tohru

2011-07-27

154

Training total communication  

Microsoft Academic Search

Background: Many people with severe or moderate aphasia begin to use nonverbal methods of communication spontaneously, but some need special training to do so. Use of total communication, including different nonverbal techniques, is often recommended to enable communication and participation in social interaction. Emphasis has also been placed on the importance of a communication partner in facilitating interaction and co-constructing

Pirkko Rautakoski

2011-01-01

155

Total portal robotic pneumonectomy.  

PubMed

Robotic pulmonary lobectomies have been reported to be technically and oncologically achievable; however, only three robotic pneumonectomy cases have been described. Two of them used a mini thoracotomy. We describe one case of a total portal robotic pneumonectomy without utility incision. We describe the step-by-step process. PMID:22983819

Rodriguez, Jose R

2012-09-15

156

Total energy by gasification  

Microsoft Academic Search

An oil gasification plant may be used as a ''total energy'' system for supplying all the various energy needs of a large chemical or refining plant. The plant would produce a low-Btu gas from medium- and high-sulfur crude using either the Shell or Texaco gasification process. Special arrangements can be included in the plant to recycle carbon formed in the

J. B. Fortuin; D. Haag

1974-01-01

157

Arthroscopic total trapeziectomy.  

PubMed

Trapeziometacarpal osteoarthritis is a common pathology resulting in severe impairments in daily living activities. Many procedures have been described in the treatment of stages Eaton II, III and IV. Bibliographical research evidences that other techniques could not improve the results of the simple trapeziectomy. A surgical technique with an arthroscopically assisted total resection of the trapezium is described. This technique is carried out with a 2.7-mm arthroscope, using the conventional portals (1R and 1U) and a fluoroscan. Surgery ends with soft dressings and rehabilitation begins immediately. In the last 9 years, we treated more than 70 patients. Video-assisted total trapeziectomy offers a simple technique with sufficient postoperative comfort that allows an early return to the daily living activities. PMID:21107227

Daroda, Sergio; Menvielle, Fernando; Cosentino, Rodolfo; Pereira, Paul

2010-12-01

158

Total synthesis of alternariol.  

PubMed

Total synthesis of alternariol, a toxic secondary metabolite of various Alternaria fungi, was achieved in seven steps starting with orcinol and 3,5-dimethoxybromobenzene. The longest linear sequence consists of six steps. Key reaction is a palladium-catalyzed Suzuki-type coupling of an orcinol-derived boronic acid with a brominated resorcylic aldehyde. The final demethylation furnished alternariol in 73% yield containing a smaller fraction of alternariol 9-methyl ether (approximately 20%). PMID:15822993

Koch, Karen; Podlech, Joachim; Pfeiffer, Erika; Metzler, Manfred

2005-04-15

159

Total Energy CMR Production  

Microsoft Academic Search

The following outlines the optimized pulsed laser deposition (PLD) procedure used to prepare Nd{sub 0.67}Sr{sub 0.33}MnO (NSMO) temperature sensors at Towson University (Prof. Rajeswari Kolagani) for the LCLS XTOD Total Energy Monitor. The samples have a sharp metal\\/insulator transition at T 200 K and are optimized for operation at T 180 K, where their sensitivity is the highest. These samples

S Friedrich; R M Kolagani

2008-01-01

160

Total variation blind deconvolution  

Microsoft Academic Search

We present a blind deconvolution algorithm based on the total variational (TV) minimization method proposed by Acar and Vogel (1994). The motivation for regularizing with the TV norm is that it is extremely effective for recovering edges of images as well as some blurring functions, e.g., motion blur and out-of-focus blur. An alternating minimization (AM) implicit iterative scheme is devised

Tony F. Chan; Chiu-Kwong Wong

1998-01-01

161

Total synthesis of ochnaflavone  

PubMed Central

Summary The first total syntheses of ochnaflavone, an asymmetric biflavone consisting of apigenin and luteolin moieties, and the permethyl ether of 2,3,2'',3''-tetrahydroochnaflavone have been achieved. The key steps in the synthesis of ochnaflavone were the formation of a diaryl ether and ring cyclization of an ether-linked dimeric chalcone to assemble the two flavone nuclei. Optimal experimental conditions for the oxidative cyclization to form ochnaflavone were established.

Ndoile, Monica M

2013-01-01

162

Total synthesis of methymycin.  

PubMed

Methynolide and 10-epi-methynolide were synthesized from the necessary segments, which were prepared by the addition of Grignard reagents to the corresponding alpha-alkoxyketones utilizing 1,2-stereochemical selection based on Cram chelation control. Ring-closing metathesis, as the key reaction, was carried out to combine the segments for the synthesis of methynolide and 10-epi-methynolide. The total synthesis of methymycin was also achieved by the glycosylation of methynolide with the trichloroimidate derivative of D-desosamine. PMID:19830295

Oh, Hong-Se; Xuan, Richeng; Kang, Han-Young

2009-08-18

163

Total quality assurance  

NASA Astrophysics Data System (ADS)

Quality, cost, and schedule are three factors affecting the competitiveness of a company; they require balancing so that products of acceptable quality are delivered, on time and at a competitive cost. Quality costs comprise investment in quality maintenance and failure costs which arise from failure to maintain standards. The basic principle for achieving the required quality at minimum cost is that of prevention of failures, etc., through production control, attention to manufacturing practices, and appropriate management and training. Total quality control involves attention to the product throughout its life cycle, including in-service performance evaluation, servicing, and maintenance.

Louzon, E.

1989-12-01

164

Total synthesis of lodopyridone.  

PubMed

A convergent total synthesis of the structurally unprecedented alkaloid lodopyridone was achieved using a cross-coupling of an iodopyridone fragment with a quinolinethiazolylstannane. Key features of the syntheses of the pentasubstituted 4-pyridone were a regioselective bromination of a 4-pyridone derived from kojic acid, a subsequent Cu-mediated introduction of the thioether, and a directed lithiation/iodination step. A chemoselective Negishi cross-coupling of a dibromothiazole and a quinolinylzinc reagent was used to assemble the chloroquinolinethiazol moiety. PMID:22909023

Burckhardt, Tobias; Harms, Klaus; Koert, Ulrich

2012-08-21

165

Total synthesis of (+)-crotogoudin.  

PubMed

Fellowship of the ring: The first total synthesis of (+)-crotogoudin, a 3,4-seco-atisane diterpenoid natural product, is reported. Asymmetric access to the bicyclo[2.2.2]octane core is achieved through a desymmetrization of a meso-diketone with baker's yeast (LG=leaving group, PG=protecting group). A SmI2 -induced radical cyclopropane-opening/annulation/elimination cascade affords the suitably decorated tetracyclic structure of (+)-crotogoudin. The synthesis led to revision of the reported optical rotation of the natural product and to assignment of its absolute configuration as an ent-atisane (5R,10R). PMID:24039092

Breitler, Simon; Carreira, Erick M

2013-08-26

166

Total quality is people  

SciTech Connect

Confronted by changing market conditions and increased global competition, in 1983 the Commercial Nuclear Fuel Division (CNFD) of Westinghouse Electric embarked on an ambitious plan to make total quality the centerpiece of its long-term business strategy. Five years later, the division's efforts in making continuous quality improvement a way of life among its more than 2,000 employees gained national recognition when it was named a charter recipient of the Malcolm Baldridge National Quality Award. What CNFD achieved during the 1980s was a cultural transformation, characterized by an empowered work force committed to a common vision. The company's quality program development strategy is described.

Vogel, C.E. (Westinghouse Electric Corp., Pittsburgh, PA (United States))

1991-01-01

167

Total Synthesis of (-)-Aplaminal  

PubMed Central

The total synthesis and assignment of absolute configuration of (?)-aplaminal (1), a cytotoxic metabolite from a sea hare possessing a triazobicyclo[3.2.1]octane skeleton, has been achieved. The synthesis entailed condensation of a monoprotected diamine (3) with dimethyl 2-oxomalonate (4) to generate the imidazolidine core (2). Introduction of the third nitrogen via Mitsunobu activation and azide displacement, followed by reduction and lactam formation (AlMe3) furnished (?)-aplaminal (1). Overall, the synthesis entailed 9 steps and proceeded in 17% overall yield.

Smith, Amos B.; Liu, Zhuqing

2009-01-01

168

Anisotropic Total Variation Filtering  

SciTech Connect

Total variation regularization and anisotropic filtering have been established as standard methods for image denoising because of their ability to detect and keep prominent edges in the data. Both methods, however, introduce artifacts: In the case of anisotropic filtering, the preservation of edges comes at the cost of the creation of additional structures out of noise; total variation regularization, on the other hand, suffers from the stair-casing effect, which leads to gradual contrast changes in homogeneous objects, especially near curved edges and corners. In order to circumvent these drawbacks, we propose to combine the two regularization techniques. To that end we replace the isotropic TV semi-norm by an anisotropic term that mirrors the directional structure of either the noisy original data or the smoothed image. We provide a detailed existence theory for our regularization method by using the concept of relaxation. The numerical examples concluding the paper show that the proposed introduction of an anisotropy to TV regularization indeed leads to improved denoising: the stair-casing effect is reduced while at the same time the creation of artifacts is suppressed.

Grasmair, Markus, E-mail: Markus.Grasmair@univie.ac.a [University of Vienna, Computational Science Center (Austria); Lenzen, Frank, E-mail: Frank.Lenzen@iwr.uni-heidelberg.d [University of Heidelberg, Heidelberg Collaboratory for Image Processing (Germany)

2010-12-15

169

Laparoscopic Total Mesorectum Excision  

PubMed Central

The main controversy of colon-rectal laparoscopic surgery comes from its use as a cancer treatment. Two points deserve special attention: the incidence of portsite tumor implantation and the possibility of performing radical cancer surgery, such as total mesorectum excision. Once these points are addressed, the laparoscopic approach will be used routinely to treat rectal cancer. To clarify these points, 32 patients with cancer of the lower rectum participated in a special protocol that included preoperative radiotherapy and laparoscopic total mesorectum excision. All data were recorded. At the same time, all data recorded from the experience of a multicenter laparoscopic group (Brazilian Colorectal Laparoscopic Surgeons – 130 patients with tumor of the lower rectum) were analyzed and compared with the data provided by our patients. Analysis of the results suggests that a laparoscopic approach allows the same effective resection as that of conventional surgery and that preoperative irradiation does not influence the incidence of intraoperative complications. The extent of lymph nodal excision is similar to that obtained with open surgery, with an average of 12.3 lymph nodes dissected per specimen. The rate of local recurrence was 3.12%. No port site implantation of tumor was noted in this series of patients with cancer of the lower rectum.

Quilici, F.A.; Cordeiro, F.; Reis, J.A.; Kagohara, O.; Simoes Neto, J.

2002-01-01

170

Total arterial myocardial revascularization.  

PubMed

The superiority of the internal thoracic artery (ITA) compared with venous conduits in terms of late graft patency is nowadays well documented. The inferior epigastric artery (IEA) was recently proposed as an alternative conduit for coronary artery surgery with good early clinical and angiographic results. To improve the benefits from myocardial revascularization, we expanded the use of these arterial conduits. From June 1988 to December 1991, 615 patients underwent coronary surgery in our institute. In 138 of them (22.4%) we performed total arterial myocardial revascularization placing 2 or more coronary anastomoses. An average of 2.37 anastomoses per patient were placed with the maximum number of 6 in one case. Only one patient died of cardiac related causes (0.72%). Perioperative morbidity included myocardial infarction and sternal dehiscence in 5 patients each (3.6%). No stroke or reoperation for bleeding occurred. No rectus muscle necrosis was recorded. Accurate preoperative planning of graft placement allows for the performance of as many as 6 distal anastomoses using bilateral ITA and single IEA grafts only, thus completely revascularizing most of the hearts with three-vessel disease. In our series this procedure was not reflected in an increase in the perioperative morbidity. We choose an elective total arterial revascularization in younger (under 65 years) patients who, while showing a lower incidence of complications in our study, are likely to derive the highest benefits from the good durability of ITA and hopefully IEA grafts. PMID:8442986

Paolini, G; Mariani, M A; Benussi, S; Zuccari, M; Di Credico, G; Gallorini, C; Grossi, A

1993-01-01

171

On total disc replacement.  

PubMed

Low back pain consumes a large part of the community's resources dedicated to health care and sick leave. Back disorders also negatively affect the individual leading to pain suffering, decreased quality-of-life and disability. Chronic low back pain (CLBP) due to degenerative disc disease (DDD) is today often treated with fusion when conservative treatment has failed and symptoms are severe. This treatment is as successful as arthroplasty is for hip arthritis in restoring the patient's quality of life and reducing disability. Even so, there are some problems with this treatment, one of these being recurrent CLBP from an adjacent segment (ASD) after primarily successful surgery. This has led to the development of alternative surgical treatments and devices that maintain or restore mobility, in order to reduce the risk for ASD. Of these new devices, the most frequently used are the disc prostheses used in Total Disc Replacement (TDR). This thesis is based on four studies comparing total disc replacement with posterior fusion. The studies are all based on a material of 152 patients with DDD in one or two segments, aged 20-55 years that were randomly treated with either posterior fusion or TDR. The first study concerned clinical outcome and complications. Follow-up was 100% at both one and two years. It revealed that both treatment groups had a clear benefit from treatment and that patients with TDR were better in almost all outcome scores at one-year follow-up. Fusion patients continued to improve during the second year. At two-year follow-up there was a remaining difference in favour of TDR for back pain. 73% in the TDR group and 63% in the fusion group were much better or totally pain-free (n.s.), while twice as many patients in the TDR group were totally pain free (30%) compared to the fusion group (15%). Time of surgery and total time in hospital were shorter in the TDR group. There was no difference in complications and reoperations, except that seventeen of the patients in the fusion group were re-operated for removal of their implants. The second study concerned sex life and sexual function. TDR is performed via an anterior approach, an approach that has been used for a long time for various procedures on the lumbar spine. A frequent complication reported in males when this approach is used is persistent retrograde ejaculation. The TDR group in this material was operated via an extra-peritoneal approach to the retroperitoneal space, and there were no cases of persistent retrograde ejaculation. There was a surprisingly high frequency of men in the fusion group reporting deterioration in ability to have an orgasm postoperatively. Preoperative sex life was severely hampered in the majority of patients in the entire material, but sex life underwent a marked improvement in both treatment groups by the two-year follow-up that correlated with reduction in back pain. The third study was on mobility in the lumbar spinal segments, where X-rays were taken in full extension and flexion prior to surgery and at two-year follow-up. Analysis of the films showed that 78% of the patients in the fusion group reached the surgical goal (non-mobility) and that 89% of the TDR patients maintained mobility. Preoperative disc height was lower than in a normative database in both groups, and remained lower in the fusion group, while it became higher in the TDR group. Mobility in the operated segment increased in the TDR group postoperatively. Mobility at the rest of the lumbar spine increased in both treatment groups. Mobility in adjacent segments was within the norm postoperatively, but slightly larger in the fusion group. In the fourth study the health economics of TDR vs Fusion was analysed. The hospital costs for the procedure were higher for patients in the fusion group compared to the TDR group, and the TDR patients were on sick-leave two months less. In all, these studies showed that the results in the TDR group were as good as in the fusion group. Patients are more likely to be totally pain-free when treated with TDR compared to fusion

Berg, Svante

2011-02-01

172

[Chronic total occlusions].  

PubMed

Many studies showed that successful recanalization of chronic total occlusion (CTO) provides an improvement of long-term outcome and left ventricular ejection fraction, electrical stability of the myocardium, increased tolerance to future coronary events, and last but not least an improvement in quality of life. Because of the perceived procedural complexity of percutaneous coronary interventions (PCI), patients with CTO are usually referred to coronary artery bypass surgery or medical therapy. Recent advances in PCI materials, devices, approaches, and techniques have allowed expert operators to tackle successfully with complex cases of CTO that many years ago would have sent patients to surgery. This has also been motivated by the long-term patency and freedom from restenosis obtained by drug-eluting stent implantation. Each strategy and device has advantages and disadvantages, even though percutaneous treatment of CTO needs a higher operator's skill with respect to other non-occlusive lesions as well as an appropriate training period. In order to avoid complications and to achieve CTO recanalization in more than 70% of cases, it is advisable to understand the principles of each strategy, to plan the proper strategy and choose the appropriate materials, to take time, to be zen and aware when to stop. PMID:18942554

Galassi, Alfredo R; Tomasello, Salvatore D; Costanzo, Luca; Tamburino, Corrado

2008-10-01

173

Total artificial heart.  

PubMed

End-stage heart failure represents a highly morbid condition for the patient with limited treatment options. From a surgical perspective, the treatment options for effective long-term survival are usually limited to heart transplantation, heart-lung transplantation or implantation of a destination mechanical circulatory support device. Assuming an advanced heart-failure patient is indeed deemed a candidate for transplantation, the patient is subject to shortages in donor organ availability and thus possible further decompensation and potential death while awaiting transplantation. Various extracorporeal and implantable ventricular-assist devices (VADs) may be able to provide temporary or long-term circulatory support for many end-stage heart-failure patients but mechanical circulatory support options for patients requiring long-term biventricular support remain limited. Implantation of a total artificial heart (TAH) currently represents one, if not the best, long-term surgical treatment option for patients requiring biventricular mechanical circulatory support as a bridge to transplant. The clinical applicability of available versions of positive displacement pumps is limited by their size and complications. Application of continuous-flow technology can help in solving some of these issues and is currently being applied in the research towards a new generation of smaller and more effective TAHs. In this review, we discuss the history of the TAH, its development and clinical application, implications for anaesthetic management, published outcomes and the future outlook for TAHs. PMID:22910087

Sale, Shiva M; Smedira, Nicholas G

2012-06-01

174

Total Solar Eclipse 2001  

NASA Astrophysics Data System (ADS)

Evaluation and assessments of informal education programs small or large such as science museum traveling exhibits interpretive kiosks hands-on activities and very large public programs have been challenging due to the diverse nature of objectives setups and expected outcomes of these programs. Almost all institutions that develop and present such programs include in their staff evaluation specialists. However for very large public outreach efforts which include participation of multi institutions located across the country larger evaluation groups/institutions can contribute more objective and extensive evaluation and assessment instruments that will help to identify weather the program was successful and if the learning objectives were achieved. Total Solar Eclipse 2001 event was participated by approximately 42000 people at museums science centers and Planetaria all over the world. I will share with you the results of an evaluation of this event that was surveyed and reported by an independent evaluation company. I will expand further on the properties of this program that helps to determine weather the program was successful or not including the discussion on how personal interest in the content publicity connectivity to a group educational as well as entertainment value and the challenges of using high technology can define success.

Craig, Nahide; Hawkins, Isabel

175

Total Laparoscopic Pancreaticoduodenectomy  

PubMed Central

Introduction: Total laparoscopic pancreaticoduodenectomy (TLPD) remains one of the most advanced laparoscopic procedures. Owing to the evolution in laparoscopic technology and instrumentation within the past decade, laparoscopic pancreaticoduodenectomy is beginning to gain wider acceptance. Methods: Data were collected for all patients who underwent a TLPD at our institution. Preoperative evaluation consisted of computed tomography scan with pancreatic protocol and selective use of magnetic resonance imaging and/or endoscopic ultrasonography. The TLPD was done with 6 ports on 3 patients and 5 ports in 2 patients and included a celiac, periportal, peripancreatic, and periduodenal lymphadenectomy. Pancreatic stents were used in all 5 cases, and intestinal continuity was re-established by intracorporeal anastomoses. Results: Five patients underwent a TLPD for suspicion of a periampullary tumor. There were 3 women and 2 men with a mean age of 60 years and a mean body mass index of 32.8. Intraoperatively, the mean operative time was 9 hours 48 minutes, with a mean blood loss of 136 mL. Postoperatively, there were no complications and a mean length of stay of 6.6 days. There was no lymph node involvement in 4 out of 5 specimens. The pathological results included intraductal papillary mucinous neoplasm in 2 patients, pancreatic adenocarcinoma in 1 patient (R0 resection), benign 4-cm periampullary adenoma in 1 patient, and a somatostatin neuroendocrine carcinoma in 1 patient (R0, N1). Conclusion: TLPD is a viable alternative to the standard Whipple procedure. Our early experience suggests decreased length of stay, quicker recovery, and improved quality of life. Complication rates appear to be improved or equivalent.

Kamyab, Armin

2013-01-01

176

Laparoscopic Total Mesorectal Excision  

PubMed Central

Objective To analyze total mesorectal excision (TME) for rectal cancer by the laparoscopic approach during a prospective nonrandomized trial. Summary Background Data Improved local control and survival rates in the treatment of rectal cancer have been reported after TME. Methods The authors conducted a prospective consecutive series of 100 laparoscopic TMEs for low and mid-rectal tumors. All patients had a sphincter-saving procedure. Case selection, surgical technique, and clinical and oncologic results were reviewed. Results The distal limit of rectal neoplasm was on average 6.1 (range 3–12) cm from the anal verge. The mean operative time was 250 (range 110–540) minutes. The conversion rate was 12%. Excluding the patient who stayed 104 days after a severe fistula and reoperation, the mean postoperative stay was 12.05 (range 5–53) days. The 30-day mortality was 2% and the overall postoperative morbidity was 36%, including 17 anastomotic leaks. Of 87 malignant cases, 70 (80.4%) had a minimum follow-up of 12 months, with a median follow-up of 45.7 (range 12–72) months. During this period 18.5% (13/70) died of cancer and 8.5% (6/70) are alive with metastatic disease. The port-site metastasis rate was 1.4% (1/70): a rectal cancer stage IV presented with a parietal recurrence at 17 months after surgery. The locoregional pelvic recurrence rate was 4.2% (3/70): three rectal cancers stage III at 19, 13, and 7 postoperative months. Conclusions Laparoscopic TME is a feasible but technically demanding procedure (12% conversion rate). This series confirms the safety of the procedure, while oncologic results are at present comparable to the open published series with the limitation of a short follow-up period. Further studies and possibly randomized series will be necessary to evaluate long-term clinical outcome in cancer patients.

Morino, Mario; Parini, Umberto; Giraudo, Giuseppe; Salval, Micky; Brachet Contul, Riccardo; Garrone, Corrado

2003-01-01

177

A Novel Technique for the Removal of Well-Fixed Cementless, Large-Diameter Metal-on-Metal Acetabular Components  

Microsoft Academic Search

Removing well-fixed cementless acetabular components can be a challenge for every orthopedic surgeon involved in revision hip arthroplasty. Forceful removal of such components often leads to acetabular bone loss and compromises reimplantation of a new socket. Instruments like the Explant Acetabular Cup Removal System (Zimmer, Warsaw, Ind) are developed to avoid such issues. We report a novel technique, cementing a

Christophe Olyslaegers; Tom Wainwright; Robert G. Middleton

2008-01-01

178

Monitoring the introduction and performance of a joint replacement: the United Kingdom metal-on-metal alert.  

PubMed

Recent events have made us question our ability to monitor the introduction and performance of a new prosthetic joint replacement. These concerns are mirrored in many other countries, even those with joint registries and other systems for detecting poorly performing implants. In the United Kingdom, as is the case in most European Union countries, we have assessment processes in place, particularly the CE (Conformité Européenne) mark, the National Joint Registry, and the Orthopaedic Data Evaluation Panel. It is important to realize that these organizations can only react to poor performance; it is not within their power as monitoring agencies to prevent a poor implant from entering the market. When an implant has been shown to perform badly, it is referred to the Medicines and Healthcare products Regulatory Agency (MHRA), which then discusses the report with the manufacturer. When it is deemed that there is unequivocal evidence of a serious problem with the implant, the MHRA issues alerts to all hospitals and practitioners. We have continuing concerns about how to assess and monitor modifications to already existing devices. Suggestions are made for improvements to this system, and the authors will welcome feedback. PMID:22262421

Tucker, Keith; Gregg, Paul; Kay, Peter; Porter, Martyn; Howard, Peter; Pickford, Martin; Cacou, Crina

2011-12-21

179

Femoral neck resorption following hybrid metal-on-metal hip resurfacing arthroplasty: a radiological and biomechanical analysis  

Microsoft Academic Search

Introduction  With the resurgence of resurfacing hip arthroplasty complications such as femoral neck fracture and thinning have been identified.\\u000a We therefore conducted a radiological and biomechanical evaluation of factors affecting femoral neck resorption following\\u000a resurfacing hip arthroplasty (RHA).\\u000a \\u000a \\u000a \\u000a \\u000a Methods  We retrospectively reviewed 61 resurfacing hip arthroplasties in 53 patients with a minimum of a 2-year follow-up. Data regarding\\u000a age, gender, body mass

Jibu Joseph; Michael Mullen; Andrew McAuley; Anand Pillai

2010-01-01

180

Lubrication of metal-on-metal hip joints: the effect of protein content and load on film formation and wear.  

PubMed

Lubricant films were measured for a series of bovine serum and protein containing (albumin, globulin) saline solutions for CoCrMo femoral component sliding against a glass disc. Central film thickness was measured by optical interferometry as a function of time (constant mean speed: 0 and 10 mm/s) and variable mean speed (0-50 mm/s). The effect of load (5-20 N) on film thickness was also studied. The development of the wear scar on the CoCrMo surface was monitored by measuring the width of the contact zone during the film thickness tests. The results showed film thickness increased with time for both the static and sliding tests. Films formed in the static, loaded test were typically in the range of 3-40 nm. The globulin containing solutions formed the thickest films. In the sliding tests a wear scar rapidly formed on the implant component for the bovine serum and albumin fluids, negligible wear was observed for the globulin solutions. Film thickness increased with sliding time for all test solutions and was much greater than predicted by isoviscous EHL models. The film increase was found to correlate with increasing wear scar size and thus decreasing contact pressure. A new lubricating mechanism is proposed whereby during sliding the fluid undergoes bulk phase separation rheology, so that an elevated protein phase forms in the inlet zone. This protein phase is a high-viscosity biphasic matrix, which is periodically entrained into the contact forming a thick protective hydro-gel film. One of the main findings of this study is that film thickness was very sensitive to load; to a much greater extent than predicted by EHL models. Thus film formation in MoM hip joints is very susceptible to high contact pressures which might be due to implant misalignment and edge-loading. PMID:22301171

Myant, C; Underwood, R; Fan, J; Cann, P M

2011-09-22

181

Total Quality Management in Construction.  

National Technical Information Service (NTIS)

The principles of Total Quality Management (TQM) provide a means for achieving quality in the construction process. The improvement of quality requires that every member of the organization embrace the principles of continuous improvement. Total Quality M...

C. C. Miller

1993-01-01

182

Corrosion at the Head-Neck Taper as a Cause for Adverse Local Tissue Reactions After Total Hip Arthroplasty  

PubMed Central

Background: Corrosion at the modular head-neck junction of the femoral component in total hip arthroplasty has been identified as a potential concern, although symptomatic adverse local tissue reactions secondary to corrosion have rarely been described. Methods: We retrospectively reviewed the records of ten patients with a metal-on-polyethylene total hip prosthesis, from three different manufacturers, who underwent revision surgery for corrosion at the modular head-neck junction. Results: All patients presented with pain or swelling around the hip, and two patients presented with recurrent instability. Serum cobalt levels were elevated prior to the revision arthroplasty and were typically more elevated than were serum chromium levels. Surgical findings included large soft-tissue masses and surrounding tissue damage with visible corrosion at the femoral head-neck junction; the two patients who presented with instability had severe damage to the hip abductor musculature. Pathology specimens consistently demonstrated areas of tissue necrosis. The patients were treated with debridement and a femoral head and liner exchange, with use of a ceramic femoral head with a titanium sleeve in eight cases. The mean Harris hip score improved from 58.1 points preoperatively to 89.7 points at a mean of 13.0 months after the revision surgery (p = 0.01). Repeat serum cobalt levels, measured in six patients at a mean of 8.0 months following revision, decreased to a mean of 1.61 ng/mL, and chromium levels were similar to prerevision levels. One patient with moderate hip abductor muscle necrosis developed recurrent instability after revision and required a second revision arthroplasty. Conclusions: Adverse local tissue reactions can occur in patients with a metal-on-polyethylene bearing secondary to corrosion at the modular femoral head-neck taper, and their presentation is similar to the adverse local tissue reactions seen in patients with a metal-on-metal bearing. Elevated serum metal levels, particularly a differential elevation of serum cobalt levels with respect to chromium levels, can be helpful in establishing this diagnosis. Level of Evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

John Cooper, H.; Della Valle, Craig J.; Berger, Richard A.; Tetreault, Matthew; Paprosky, Wayne G.; Sporer, Scott M.; Jacobs, Joshua J.

2012-01-01

183

Total Quality and Organization Development. Total Quality Series.  

ERIC Educational Resources Information Center

|As the global business environment becomes more turbulent, quality management seems more indispensable. This book offers strategies for integrating the theory and practice of Total Quality Management (TQM) with organizational-development (OD) theory at all organizational levels. Chapter 1 answers the question "Why Total Quality Management and…

Lindsay, William M.; Petrick, Joseph A.

184

The total charm cross section  

SciTech Connect

We assess the theoretical uncertainties on the total charm cross section. We discuss the importance of the quark mass, the scale choice and the parton densities on the estimate of the uncertainty. We conclude that the uncertainty on the total charm cross section is difficult to quantify.

Vogt, R

2007-09-14

185

Total Liability for Excessive Harm  

Microsoft Academic Search

The harm that each individual causes others is unverifiable in some circumstances where the total harm caused by everyone is verifiable. For example, the environmental agency can often measure the total harm caused by pollution much easier than it can measure the harm caused by each individual polluter. In these circumstances, implementing the usual liability rules or externality taxes is

Robert D. Cooter; Ariel Porat

2005-01-01

186

Labor participation rate, total (% of total population ages 15+)  

NSDL National Science Digital Library

Data set and map pertaining to total labor force participation rates for all countries. The World Bank specifies labor force participation as a World Development Indicator (WDI) -- the statistical benchmark that helps measure the progress of development.

Bank, World

187

Scheme for total quantum teleportation  

PubMed

We address the issue of totally teleporting the quantum state of an external particle, as opposed to studies on partial teleportation of external single-particle states, total teleportation of coherent states and encoded single-particle states, and intramolecular teleportation of nuclear spin states. We find a set of commuting observables whose measurement directly projects onto the Bell basis and discuss a possible experiment, based on two-photon absorption, allowing, for the first time, total teleportation of the state of a single external photon through a direct projective measurement. PMID:11018993

DelRe; Crosignani; Di Porto P

2000-03-27

188

Controversies in total ankle replacement.  

PubMed

Although there exist general guidelines regarding which patients are "suitable" candidates for total ankle replacement, these guidelines tend to be very conservative, much like those of knee and hip replacement from decades ago. There are also no direct comparison studies of one total ankle replacement design with another. Because of the paucity of data, surgeons are left to surmise the opinion based on limited studies, as well as industry-sponsored data and advertising material. This article examines several key, controversial issues that apply to total ankle replacement. Recommendations and points for thought are provided. PMID:23164437

Bibbo, Christopher

2012-10-06

189

Total anomalous systemic venous return.  

PubMed

We have described an 18-year-old boy who is asymptomatic nine years after surgical correction of total anomalous systemic venous return. His clinical course and anatomy are compared to the eight previously reported patients. PMID:7355335

Pearl, W R; Spicer, M J

1980-02-01

190

United States: Total Cardiovascular Diseases.  

National Technical Information Service (NTIS)

Presents 1995 death rates for the following diseases: Total cardiovascular diseases; Ischemic heart diseases; Stroke; All cancers; Lung cancer; Colorectal cancer; Breast cancer; Diabetes; Cigarette smoking; No leisure time physical activity among adults; ...

1996-01-01

191

Total Diet Study - Analytical Results  

Center for Food Safety and Applied Nutrition (CFSAN)

Results of the Total Diet Study from mind-1991 to the present for elemental analytes, radionuclides, pesticide residues, industrial chemicals, mercury ... More results from www.fda.gov/food/foodscienceresearch/totaldietstudy

192

Total hip and total knee replacement: preoperative nursing management.  

PubMed

Total hip replacement (THR) and total knee replacement (TKR) surgery are carried out for the relief of hip or knee pain, usually caused by osteoarthritis. This is the first of two articles on THR and TKR. It will outline the different types of replacement used in lower limb joint replacement surgery. Preparation of patients for surgery requires attention to physical, psychological and social factors and these are explored in detail. The organization of services along the patient pathway to ensure comprehensive preparation is considered and the nursing role highlighted. The second article, to be published in the next issue, will discuss recovery and rehabilitation from THR and TKR surgery. PMID:19060818

Lucas, Brian

193

Total body water and total body potassium in anorexia nervosa  

SciTech Connect

In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation.

Dempsey, D.T.; Crosby, L.O.; Lusk, E.; Oberlander, J.L.; Pertschuk, M.J.; Mullen, J.L.

1984-08-01

194

Total eclipses of the sun.  

PubMed

Total eclipses of the sun offer research opportunities in a variety of sciences. Some of the advances in solar physics resulting from eclipse observations are discussed. Experiments at the total eclipse of 16 February 1980 in India are also described. These included a test of general relativity, studies in coronal physics, investigations of solar prominences, diameter measurements, a search for interplanetary dust, a study of the gravity waves in the earth's atmosphere, and experiments on the biological effects on animals and humans. PMID:17817829

Zirker, J B

1980-12-19

195

Prenatal diagnosis of total arhinia.  

PubMed

Complete or total arhinia, in which there is absence of the soft tissue of the nose, is extremely rare. The embryological origin of the defect is thought to be maldevelopment of the paired nasal placodes. Available neonatal case descriptions have reported the frequent coexistence of other facial anomalies. This report is the first to describe the antenatal diagnosis of total arhinia confirmed after delivery. Sonographic views of the fetal profile, showing an absence of the nose led to consideration of the diagnosis. PMID:10846785

Cusick, W; Sullivan, C A; Rojas, B; Poole, A E; Poole, D A

2000-03-01

196

Total hip and total knee replacement: postoperative nursing management.  

PubMed

Patients having total hip replacement (THR) or total knee replacement (TKR) surgery require skilled nursing care in order to recover from surgery and anaesthesia. The first part of this article will outline the key nursing management issues during the postoperative stage of recovery. The second part will consider the longer term recovery, including the risk of THR dislocation and failure of the prosthesis due to loosening or infection. The role of the nurse in primary and secondary care in monitoring and identifying complications will be highlighted. This is the second of two articles on nursing care for patients undergoing THR or TKR surgery. The first article (Lucas, 2008) looked at preoperative nursing care. PMID:19057500

Lucas, Brian

197

Total alloplastic middle ear implant.  

PubMed

A total alloplastic middle ear prosthesis (TAM), composed of a spongy substance consisting of Teflon and pyrolytic graphite is presented. This prosthesis allows a safe eradication of the diseased tissue and approximates a physiological reconstruction of the sound conducting system. The results obtained in three patients with this TAM up to an observation period of more than two years are promising. PMID:7406761

Grote, J J; Kuijpers, W

1980-09-01

198

Total synthesis of (+)-scholarisine A.  

PubMed

An effective total synthesis and assignment of the absolute configuration of the architecturally challenging compound (+)-scholarisine A has been achieved via a 20-step sequence. Highlights include a reductive cyclization involving a nitrile and an epoxide, a modified Fischer indole protocol, a late-stage oxidative lactonization, and an intramolecular cyclization leading to the indolenine ring system of (+)-scholarisine A. PMID:22280070

Adams, Gregory L; Carroll, Patrick J; Smith, Amos B

2012-01-25

199

Total system heat loss measurements  

Microsoft Academic Search

Excessive heat losses from insulated systems in service raise critical design questions when compared with performance data obtained from individual insulation specimens tested in the laboratory. In many cases, excessive heat loss is caused by the incorrect design assumption that total system heat loss is equal only to that through individual insulation sections. However, additional heat losses result from the

B. A. Allmon; D. A. Rausch; H. W. Wahle

1983-01-01

200

Infection Following Total Knee Arthroplasty  

PubMed Central

For most orthopedists, total knee arthroplasty (TKA) has been regarded as the most effective surgery for patients with severe knee diseases. Though seldom occur, postoperative infection certainly remains one of the most devastating and dreaded complications of TKA. Thus, careful and early diagnosis is needed. After diagnosis, categorize the infection type and choose a rightful and sequential step of treatment are recommended.

Chun, Keun Churl; Kim, Kwang Mee

2013-01-01

201

Total Quality Management for Schools.  

ERIC Educational Resources Information Center

|Education in the United Kingdom has been shaped by the advent of local school management and the rapid growth of grant-maintained schools. Total Quality Management (TQM) offers a new way of looking at management principles and structures by identifying the needs of both internal and external customers. This book applies principles of TQM…

Greenwood, Malcolm S.; Gaunt, Helen J.

202

Total Quality Management for Schools.  

ERIC Educational Resources Information Center

Education in the United Kingdom has been shaped by the advent of local school management and the rapid growth of grant-maintained schools. Total Quality Management (TQM) offers a new way of looking at management principles and structures by identifying the needs of both internal and external customers. This book applies principles of TQM…

Greenwood, Malcolm S.; Gaunt, Helen J.

203

What is Total Quality Management?  

ERIC Educational Resources Information Center

|Provides a general overview of Total Quality Management (TQM) and explains why there is pressure for change in higher education institutions. Defines TQM and the various themes, tools, and beliefs that make it different from other management approaches. Presents 14 principles and how they might be applied to student affairs. (RJM)|

Bryan, William A.

1996-01-01

204

Mastalgia and total body water  

Microsoft Academic Search

Total body water (TBW) was measured early and late in a menstrual cycle in 56 women, 39 of whom had breast pain. The remainder were asymphtomatic controls. Most women did not conform to the traditional view that there is a premenstrual increase in TBW. In some TBW decreased, while in others there was no change from the early cycle measurement.

P E Preece; A R Richards; G M Owen; L E Hughes

1975-01-01

205

Total synthesis of pyoverdin D.  

PubMed

Pyoverdin D is an important siderophore that is used by the human pathogen Pseudomonas aeruginosa to import iron and gain a competitive advantage. This unique partially cyclic octapeptide bears four nonproteinogenic amino acids, including (?)N-formyl-(?)N-hydroxy-l-ornithine, and a catechol containing chiral chromophore. Here, we report the first total synthesis of pyoverdin D. PMID:23530778

Mashiach, Roi; Meijler, Michael M

2013-03-26

206

Total Synthesis of (+)-Scholarisine A  

PubMed Central

An effective total synthesis and assignment of the absolute configuration of the architecturally challenging (+)-scholarisine A has been achieved via a 20-step sequence. Highlights include a reductive cyclization, involving a nitrile and an epoxide; a modified Fischer indole protocol; a late stage oxidative-lactonization; and an intramolecular cyclization leading to the indolenine ring system of (+)-scholarisine A.

Adams, Gregory L.; Carroll, Patrick J.; Smith, Amos B.

2012-01-01

207

Enantioselective Total Synthesis of (+)-Cassiol  

PubMed Central

An enantioselective total synthesis of (+)-cassiol is reported. The complex derived from Pd2(pmdba)3 and enantiopure t-BuPHOX ligand catalyzes enantioconvergent decarboxylative alkylation to generate the quaternary carbon stereocenter at an early stage. The overall synthetic strategy involves a convergent late-stage coupling of two fragments. The synthesis features a longest linear sequence of eight steps.

Petrova, Krastina V.; Mohr, Justin T.; Stoltz, Brian M.

2009-01-01

208

Total synthesis of cladoniamide G.  

PubMed

The total synthesis of cladoniamide G, a cytotoxic compound against MCF-7 breast cancer cells (10 ?g/mL), was accomplished. Key steps in the sequence include oxidative dimerization of 3-acetoxy-5-chloroindole and a tandem process incorporating three steps: bimolecular carbonyl addition, lactam formation, and carbamate removal. PMID:23413919

Loosley, Benjamin C; Andersen, Raymond J; Dake, Gregory R

2013-02-15

209

[Total radiocarpal prosthesis. Preliminary study].  

PubMed

The mechanical requirements before satisfactory muscular balance in a total wrist prosthesis have been studied in 25 cadavers. The centre of rotation was determined in X-Rays; it was localised in the sagittal plane crossing the axis of the forearm and in the frontal plane situated in front of the axis of the forearm. A graphic model of the wrist was then established. A total prosthesis was then designed, made up of two components with a torus surface. This prosthesis was found to be compatible with the wrist model. Movement required forces only slightly greater than normal muscular activity. One male was operated on using this prosthesis. The result was satisfactory after one year. PMID:3749550

Gagey, O; Lanoy, J F; Mazas, Y; Mazas, F

1986-01-01

210

Total and subtotal abdominal hysterectomy.  

PubMed

Hysterectomy is one of the most frequently performed operations in the world, accounting for 500,000-600,000 procedures annually in the USA; the abdominal route for hysterectomy is the preferred route in 60-80% of these operations. Although the number of total abdominal hysterectomies performed annually has decreased, the number of subtotal abdominal hysterectomies increased by >400%. The major indications for abdominal hysterectomy include abnormal uterine bleeding, myomata uteri, adenomyosis, endometriosis, neoplasia, and chronic salpingitis. The basis for selection for subtotal versus total hysterectomy has little in the way of factual data to support it and may actually present some significant disadvantages, such as continued menstruation and cervical prolapse. The detailed technique for performing intrafascial abdominal hysterectomy relies heavily on precise knowledge of pelvic anatomy and compulsive detail to tissue handling. The consistent and correct usage of prophylactic antimicrobials, measures to prevent thromboemboli, and procedures to avoid urinary retention are key to the overall success of the surgery. PMID:15985251

Baggish, Michael S

2005-02-05

211

Acceleration using total internal reflection  

SciTech Connect

This report considers the use of a dielectric slab undergoing total internal reflection as an accelerating structure for charged particle beams. We examine the functional dependence of the electromagnetic fields above the surface of the dielectric for polarized incident waves. We present an experimental arrangement for testing the performance of the method, using apparatus under construction for the Grating Acceleration experiment at Brookhaven National Laboratory. 13 refs., 4 figs., 2 tabs.

Fernow, R.C.

1991-06-07

212

Total pancreatectomy for chronic pancreatitis.  

PubMed

Ten instances of total pancreatectomy performed for chronic alcohol induced pancreatitis are reported. There was no hospital mortality, and all of the patients were free of pain. The most difficult problem was labile insulin sensitive diabetes in these patients who were chronic alcoholics. In addition, steatorrhea with weight loss, bleeding marginal ulcers and general weakness diminished working ability. The present data suggest that this procedure should be considered as the last resort in the treatment of severe instances of chronic pancreatitis. PMID:3883550

Kiviluoto, T; Schröder, T; Lempinen, M

1985-03-01

213

Asymmetric total synthesis of rollicosin.  

PubMed

[structure: see text] The first total synthesis of rollicosin, a member of a rare subgroup of Annonaceous acetogenins containing two terminal gamma-lactones, is reported. The approach features a highly regio- and stereoselective tandem ring-closing/cross-metathesis reaction for construction of the east-wing lactone and incorporation of the alkyl spacer. Establishment of the C4 stereocenter and addition of the west-wing lactone were achieved by Sharpless asymmetric dihydroxylation and enolate alkylation. PMID:15787477

Quinn, Kevin J; Isaacs, André K; DeChristopher, Brian A; Szklarz, Stephanie C; Arvary, Rebecca A

2005-03-31

214

Total Synthesis of Aplyronine C  

PubMed Central

A highly stereocontrolled total synthesis of the cytotoxic marine macrolide aplyronine C is described. The route exploits aldol methodology to install the requisite stereochemistry and features a crucial boron-mediated aldol coupling of an N-vinylformamide-bearing methyl ketone with a macrocyclic aldehyde to introduce the full side chain. The synthesis of two novel C21–C34 side chain analogs is also reported.

2013-01-01

215

Total synthesis of (-)-callipeltoside A.  

PubMed

A total synthesis of (-)-callipeltoside A (1) has been achieved. The core macrocycle was made via a dual macrolactonization/pyran hemiketal formation reaction, developed to circumvent issues related to the reversible nature of acylketene formation from ?-keto lactone substrates. Initial approaches to the core of the natural product that revolved around ring-closing metathesis (RCM) and relay ring-closing metathesis (RRCM) reactions are also described. PMID:20932014

Hoye, Thomas R; Danielson, Michael E; May, Aaron E; Zhao, Hongyu

2010-11-01

216

Thrombocytopenia after total knee arthroplasty.  

PubMed

Heparin-induced thrombocytopenia is a serious complication during antithromboembolic prophylaxis caused by anti-heparin/platelet factor 4 (PF4) complex antibodies. It typically arises 3 to 15 days after the beginning of therapy and may result in an increased risk of arterial and venous thromboembolism. This article presents a case of thrombocytopenia associated with vein thrombosis in a man who underwent a total knee arthroplasty (TKA). PMID:19226055

Pesce, Vito; Patella, Vittorio; Scaraggi, Antonio; Petrera, Massimo; Sammarco, Giulio; Spinarelli, Antonio

2008-12-01

217

Total Synthesis of 7?-Desmethylkealiiquinone  

PubMed Central

The total synthesis of an analog of the marine alkaloid kealiiquinone has been completed through application of an intramolecular Diels-Alder reaction of an imidazole-containing enyne. Oxidative aromatization of the lactone adduct and N-methylation facilitates C2-oxidation via the imidazolium salt. Conversion of the lactone to the phthalaldehyde derivative and then to the dihydroxybenzoquinone was achieved via a reaction with glyoxal in the presence of KCN. Esterification of the vinylogous diacid and deprotection provided 7?-desmethylkealiiquinone.

Lima, Heather M.; Sivappa, Rasapalli; Yousufuddin, Muhammed; Lovely, Carl J.

2012-01-01

218

Total thyroidectomy: Complications and technique  

Microsoft Academic Search

During the 27-year period from 1957 to 1984, four hundred thirty patients underwent total thyroidectomies for malignant or benign disease of the thyroid gland at our institutions. Thyroid cancer was found in 83.4% of cases, and 47.2% of these had concomitant lymph node dissections. Transient recurrent laryngeal nerve injury occurred in 6.2% of the entire series. Permanent unilateral vocal cord

Jay K. Harness; Lit Fung; Norman W. Thompson; Richard E. Burney; Michael K. McLeod

1986-01-01

219

Asymmetric Total Synthesis of Pyranicin  

PubMed Central

The asymmetric total synthesis of pyranicin (1) is reported. The butenolide ring was constructed via an asymmetric alkylation/ring-closing metathesis strategy. The three stereocenters in the left-hand tetrahydropyran ring were installed by sequential chiral auxiliary-mediated aldol reactions. Closure of the tetrahydropyran and fusion of the alkyl backbone were affected via a sequential ring-closing metathesis cross-metathesis strategy.

Crimmins, Michael T.; Jacobs, Danielle L.

2010-01-01

220

Antarctic total ozone in 1958  

SciTech Connect

The Antarctic ozone hole results from catalytic destruction of ozone by chlorine radicals. The hole develops in August, reaches its full depth in early October, and is gone by early December of each year. Extremely low total ozone measurements were made at the Antarctic Dumont d'Urville station in 1958. These measurements were derived from spectrographic plates of the blue sky, the moon, and two stars. These Dumont plate data are inconsistent with 1958 Dobson spectrophotometer ozone measurements, inconsistent with present-day Antarctic observations, and inconsistent with meteorological and theoretical information. There is no credible evidence for an ozone hole in 1958.

Newman, P.A. (NASA/Goddard Space Flight Center, Greenbelt, MD (United States))

1994-04-22

221

Total synthesis of (+)-superstolide A.  

PubMed

A convergent and highly stereocontrolled total synthesis of the cytotoxic macrolide (+)-superstolide A is described. Key features of this synthesis include the use of bimetallic linchpin 36b for uniting the C(1)-C(15) (43) and the C(20)-C(27) (38) fragments of the natural product, a late-stage Suzuki macrocyclization of 49, and a highly diastereoselective transannular Diels-Alder reaction of macrocyclic octaene 4. In contrast, the intramolecular Diels-Alder reaction of pentaenal 5 provided the desired cycloadduct with lower stereoselectivity (6:1:1). PMID:18956845

Tortosa, Mariola; Yakelis, Neal A; Roush, William R

2008-12-19

222

Total Synthesis of (+)-Superstolide A  

PubMed Central

A convergent and highly stereocontrolled total synthesis of the cytotoxic macrolide (+)-superstolide A is described. Key features of this synthesis include the use of bimetallic linchpin 36b for uniting the C(1)-C(15) (43) and the C(20)-C(27) (38) fragments of the natural product, a late-stage Suzuki macrocyclization of 49, and a highly diastereoselective transannular Diels-Alder reaction of macrocyclic octanene 4. In contrast, the intramolecular Diels-Alder reaction of pentaenal 5 provided the desired cycloadduct with lower stereoselectivity (6:1:1).

Tortosa, Mariola; Yakelis, Neal A.; Roush, William R.

2009-01-01

223

Total quality in health care.  

PubMed

Quality is at the top of American consumers' demand list, and consequently American manufacturing companies have been forced to assign priority to the development of high-quality products. To improve the quality of what they offer, many manufacturers use the management philosophy known as total quality management (TQM), and now the service sector is following in their footsteps. The health care industry is a good example of a service industry that can benefit greatly from TQM, and it is the purpose of this article to show how a health care provider can implement TQM and evaluate its effects. PMID:10178544

Brannan, K M

1998-05-01

224

Concise total synthesis of spirocurcasone.  

PubMed

A concise total synthesis of spirocurcasone was accomplished. Key features of the synthesis involved a vinylogous Mukaiyama aldol reaction, a Carroll rearrangement of ?-keto allyl ester derivative, an intramolecular aldol condensation, and a spiro ring formation by ring-closing metathesis of the pentaene compound. This synthetic work was complete in nine steps from (S)- or (R)-perillaldehyde without the use of protecting groups. Interestingly, the optical rotation of the synthetic spirocurcasone was different from the reported value of the natural product. PMID:23448402

Abe, Hideki; Sato, Akimi; Kobayashi, Toyoharu; Ito, Hisanaka

2013-02-28

225

Total Synthesis of (+)-Sieboldine A  

PubMed Central

The first total synthesis of (+)-sieboldine A was completed in 20 steps from readily available (3aS,6aR)-3,3a,4,6-atetrahydro-2H-cyclopenta[b]furan-2-one (5). Key steps are: (a) a pinacol-terminated 1,6-enyne cyclization reaction to form the cis-hydrindanone core (11 ? 12), (b) formation of the spiro tetrahydrofuran ring by stereoselective DMDO oxidation of tricyclic dihydropyran intermediate 15, and (c) formation of the unprecedented N-hydroxyazacyclononane ring by cyclization of a thioglycoside precursor (18 ? 19).

Canham, Stephen M.; France, David J.

2010-01-01

226

Rotating-hinge total knee for revision total knee arthroplasty.  

PubMed

Rotating-hinge knee implants are used for revision total knee arthroplasty in patients with severe ligament instability and bone loss. This study evaluated the outcomes of a series of rotating-hinge knees. Thirty-one NexGen Rotating Hinge Knees (Zimmer, Warsaw, Indiana) were implanted in 29 patients (2 bilateral), with an average age of 72.8 years. Indications for surgery were aseptic loosening (n=23), septic loosenings (n=4), tibiofemoral instability (n=3), and wear (n=1). The Hospital for Special Surgery Knee Score and the Knee Society Roentgenographic Evaluation System were used. Statistical and cumulative survival rate analyses were performed. Average follow-up was 60.3 months (range, 32-100 months). The Hospital for Special Surgery Knee Score results indicated statistically significant improvement; the total score increased from 65.5 preoperatively to 88.4 postoperatively. Average range of motion increased from 90.9° preoperatively to 114.4° postoperatively. Radiographs showed no periprosthetic bone fractures or implant ruptures. Radiolucent lines were found in 20 of 26 patients and were progressive in 2 (both revised). Complications occurred in 10 patients. The rigidity of the hinge may be associated with a risk of aseptic loosening due to the increased stress transfer to the bone from the prosthesis through the locked hinge. Rotating-hinge knee implants provided acceptable mid-term outcomes for revision knee surgery with ligamentous instability. They are not at higher risk for early loosening unless short tibial stems are used. The high percentage of failures is more related to the complex surgery and to the status of the patients than to the hinged mechanism. PMID:22385441

Bistolfi, Alessandro; Massazza, Giuseppe; Rosso, Federica; Crova, Maurizio

2012-03-07

227

Solar total energy project Shenandoah  

SciTech Connect

This document presents the description of the final design for the Solar Total Energy System (STES) to be installed at the Shenandoah, Georgia, site for utilization by the Bleyle knitwear plant. The system is a fully cascaded total energy system design featuring high temperature paraboloidal dish solar collectors with a 235 concentration ratio, a steam Rankine cycle power conversion system capable of supplying 100 to 400 kW(e) output with an intermediate process steam take-off point, and a back pressure condenser for heating and cooling. The design also includes an integrated control system employing the supervisory control concept to allow maximum experimental flexibility. The system design criteria and requirements are presented including the performance criteria and operating requirements, environmental conditions of operation; interface requirements with the Bleyle plant and the Georgia Power Company lines; maintenance, reliability, and testing requirements; health and safety requirements; and other applicable ordinances and codes. The major subsystems of the STES are described including the Solar Collection Subysystem (SCS), the Power Conversion Subsystem (PCS), the Thermal Utilization Subsystem (TUS), the Control and Instrumentation Subsystem (CAIS), and the Electrical Subsystem (ES). Each of these sections include design criteria and operational requirements specific to the subsystem, including interface requirements with the other subsystems, maintenance and reliability requirements, and testing and acceptance criteria. (WHK)

None

1980-01-10

228

Pharyngocutaneous fistula following total laryngectomy  

PubMed Central

Summary Pharyngocutaneous fistula is the most common complication after total laryngectomy. The aim of the study was to establish the incidence of this complication in our series and analyse the predisposing factors. This is a retrospective study comprising 55 patients who underwent total laryngectomy. The following aspects were considered: sex, age, tumour site, pathologic staging according to TNM, performance and type of neck dissection, previous radiation therapy, previous tracheotomy, Cumulative Illness Rating Scale for comorbidity analysis, the use of stapler for pharyngeal closure, and peri-operative blood transfusion. In the cases of pharyngocutaneous fistula, we considered the post-operative period in which it was diagnosed, duration, period of hospitalization, as well as therapeutic approach and the eventual result of this treatment. Pharyngocutaneous fistula was diagnosed in 7 patients (12.7%). There were no statistically significant associations between fistula development and sex (p = 1.000), previous radiation therapy (p = 0.354), stapler closure (p = 0.577), comorbidity (p = 1.000) or tumour site (p = 0.926). Patients previously submitted to tracheotomy presented higher fistula incidence (60%), compared to those that had not undergone this procedure (8%) (p = 0.012). Elderly patients (> 60 years) were also more predisposed to fistula development (p = 0.051). Although without statistical significance, fistula development was also associated with peri-operative blood transfusion, T stage, and type of neck dissection.

Dedivitis, RA; Ribeiro, KCB; Castro, MAF; Nascimento, PC

2007-01-01

229

"Total IBA" - Where are we?  

NASA Astrophysics Data System (ADS)

The suite of techniques which are available with the small accelerators used for MeV ion beam analysis (IBA) range from broad beams, microbeams or external beams using the various particle and photon spectrometries (including RBS, EBS, ERD, STIM, PIXE, PIGE, NRA and their variants), to tomography and secondary particle spectrometries like MeV-SIMS. These can potentially yield almost everything there is to know about the 3-D elemental composition of types of samples that have always been hard to analyse, given the sensitivity and the spacial resolution of the techniques used. Molecular and chemical information is available in principle with, respectively, MeV-SIMS and high resolution PIXE. However, these techniques separately give only partial information - the secret of "Total IBA" is to find synergies between techniques used simultaneously which efficiently give extra information. We here review how far "Total IBA" can be considered already a reality, and what further needs to be done to realise its full potential.

Jeynes, C.; Bailey, M. J.; Bright, N. J.; Christopher, M. E.; Grime, G. W.; Jones, B. N.; Palitsin, V. V.; Webb, R. P.

2012-01-01

230

Total elbow arthroplasty: current options.  

PubMed

Total elbow arthroplasty (TEA) has changed considerably in the past three decades. Based on the good long-term results with TEA in patients with rheumatoid arthritis, the indications expanded to include management of acute traumatic and posttraumatic conditions in young, higher-demand patients. Today, unlinked, linked semiconstrained, and convertible devices are available. The high complication rate with earlier surgeries led to surgical advances such as new cementing technique and a focus on managing the triceps. Complications such as infection, aseptic loosening, polyethylene wear, periprosthetic fracture, triceps insufficiency, wound breakdown, and ulnar nerve injury will continue to spur the evolution of surgical technique and implant design. Refinement of surgical indications and improvement in implant fixation, polyethylene design, component implantation, and pathology-specific implants will determine the future success of TEA. PMID:23818030

Choo, Andrew; Ramsey, Matthew L

2013-07-01

231

Total Maximum Daily Load Program  

NSDL National Science Digital Library

The Environmental Protection Agency (EPA) provides this informative resource on Total Maximum Daily Loads (TMDL). A term used to discuss water quality, TMDL refers to "a calculation of the maximum amount of a pollutant that a water body can receive and still meet water quality standards." The TMDL Program Website offers background information on TMDLs (including FAQs), a National Overview of Impaired Waters in the US, and two standard presentations on TMDLs (HTML and Power Point). The heart of the site, however, is the interactive map of the US, which allows users access to each state's TMDL Program. Within each state, watershed names and maps, as well as source information (Water body, Parameter of Concern, Priority for TMDL Development), are provided.

232

Total synthesis of nhatrangin a.  

PubMed

A concise and stereoselective approach for the synthesis of key intermediates for aplysiatoxins, oscillatoxins, and nhatrangins and their utility for the total synthesis of nhatrangin A has been demonstrated. The advanced intermediates aromatic aldehyde 11 and dihydroxy acid 12 were synthesized in eight steps (44% overall yield) and three steps (55% overall yield), respectively. An asymmetric Michael addition, CBS reduction, and proline-catalyzed crossed-aldol reactions were utilized as key steps for the generation of all the chirality of main chain hydroxyaldehyde, while the appended side-chain-protected 3,4-dihydroxypentanoic acid was achieved in a shortest route, using Sharpless dihydroxylation, diol protection, and RuO4-catalyzed aromatic over-oxidation reactions. Synthesis of nhatrangin A was accomplished by coupling of dihydroxy acid 12 with ?-hydroxyallyl ester (obtained from 11) under Yamaguchi reaction conditions followed by a one-pot deprotection of all protecting groups. PMID:23927003

Yadav, Jhillu Singh; Rajendar, Goreti; Rao, Ramisetti Srinivasa; Pabbaraja, Srihari

2013-08-21

233

Apparatus for total immersion photography  

US Patent & Trademark Office Database

Total Immersion Photography (TIP) is disclosed, preferably for the use of screening for various medical and cosmetic conditions. TIP, in a preferred embodiment, comprises an enclosed structure that may be sized in accordance with an entire person, or individual body parts. Disposed therein are a plurality of imaging means which may gather a variety of information, e.g., chemical, light, temperature, etc. In a preferred embodiment, a computer and plurality of USB hubs are used to remotely operate and control digital cameras. The photo information is then transferred via the USB to the computer for processing and aggregation. Subject information is gathered to configure the operation of the various parameters of the device.

2008-04-15

234

TVD: Total Variation Diminishing code  

NASA Astrophysics Data System (ADS)

TVD solves the magnetohydrodynamic (MHD) equations by updating the fluid variables along each direction using the flux-conservative, second-order, total variation diminishing (TVD), upwind scheme of Jin & Xin. The magnetic field is updated separately in two-dimensional advection-constraint steps. The electromotive force (EMF) is computed in the advection step using the TVD scheme, and this same EMF is used immediately in the constraint step in order to preserve ?·B=0 without the need to store intermediate fluxes. The code is extended to three dimensions using operator splitting, and Runge-Kutta is used to get second-order accuracy in time. TVD offers high-resolution per grid cell, second-order accuracy in space and time, and enforcement of the ?·B=0 constraint to machine precision. Written in Fortran, It has no memory overhead and is fast. It is also available in a fully scalable message-passing parallel MPI implementation.

Pen, Ue-Li; Arras, Phil; Wong, ShingKwong

2013-04-01

235

[Update on total hip arthroplasty].  

PubMed

Total hip arthroplasty (THA) is one of the most common surgical procedures performed by orthopedic surgeons. Frequent indications for THA include osteoarthrosis of the hip joint that can be primary origin or secondary to dysplasia or traumatic origin, as well as fractures of the femoral neck in active patients. Other common indications include rheumatoid arthritis and osteonecrosis of the femoral head. It is a surgical intervention giving very good results giving patients pain relief and mobility with a success rate in more than 90% of cases. The point of this article is to inform the medical community on the actual situation of hip prosthetics in fields including epidemiology, clinical results, indications, contraindications, different types of prosthetic materials as well as surgical approaches. PMID:21250424

Christofilopoulos, Panayiotis; Lübbeke, Anne; Peter, Robin; Hoffmeyer, Pierre

2010-12-22

236

Enantioselective total synthesis of (+)-dibromophakellstatin.  

PubMed

The first enantioselective total synthesis of (+)-phakellstatin and (+)-dibromophakellstatin was achieved. Key steps in the synthesis were a desymmetrization of the diketopiperazine (S,S)-cyclo (Pro, Pro) via a diastereoselective acylation, an intramolecular Mitsunobu reaction to introduce the C6 aminal, and a tandem Hofmann rearrangement/cyclization to simultaneously introduce the C10 quaternary aminal center and deliver the cyclic urea. The synthesis also demonstrates the unusual stability of pyrrolo aminals. Importantly, this strategy has the potential for producing phakellstatin derivatives, derived from (R,R)-cyclo (Pro, Pro), necessary for biological studies. A similar annulation protocol is also expected to be applicable to the synthesis of palau'amine. PMID:12785755

Poullennec, Karine G; Romo, Daniel

2003-05-28

237

Total quality management program planning  

SciTech Connect

As government funding grows scarce, competition between the national laboratories is increasing dramatically. In this era of tougher competition, there is no for resistance to change. There must instead be a uniform commitment to improving the overall quality of our products (research and technology) and an increased focus on our customers` needs. There has been an ongoing effort to bring the principles of total quality management (TQM) to all Energy Systems employees to help them better prepare for future changes while responding to the pressures on federal budgets. The need exists for instituting a vigorous program of education and training to an understanding of the techniques needed to improve and initiate a change in organizational culture. The TQM facilitator is responsible for educating the work force on the benefits of self-managed work teams, designing a program of instruction for implementation, and thus getting TQM off the ground at the worker and first-line supervisory levels so that the benefits can flow back up. This program plan presents a conceptual model for TQM in the form of a hot air balloon. In this model, there are numerous factors which can individually and collectively impede the progress of TQM within the division and the Laboratory. When these factors are addressed and corrected, the benefits of TQM become more visible. As this occurs, it is hoped that workers and management alike will grasp the ``total quality`` concept as an acceptable agent for change and continual improvement. TQM can then rise to the occasion and take its rightful place as an integral and valid step in the Laboratory`s formula for survival.

Thornton, P.T.; Spence, K.

1994-05-01

238

Asymmetric Total Synthesis of Vindoline  

PubMed Central

A concise asymmetric total synthesis of (?)-vindoline (1) is detailed based on a tandem intramolecular [4+2]/[3+2] cycloaddition cascade of a 1,3,4-oxadiazole inspired by the natural product structure, in which the tether linking the initiating dienophile and oxadiazole bears a chiral substituent that controls the facial selectivity of the initiating Diels–Alder reaction and sets absolute stereochemistry of the remaining six stereocenters in the cascade cycloadduct. This key reaction introduces three rings and four C–C bonds central to the pentacyclic ring system setting all six stereocenters and introducing essentially all the functionality found in the natural product in a single step. Implementation of the approach also required the development of a unique ring expansion reaction to provide a 6-membered ring suitably functionalized for introduction of the ?6,7-double bond found in the core structure of vindoline and defined our use of a protected hydroxymethyl group as the substituent used to control the stereochemical course of the cycloaddition cascade.

Kato, Daisuke; Sasaki, Yoshikazu; Boger, Dale L.

2010-01-01

239

[Vocational Rehabilitation after Total Laryngectomy.  

PubMed

Aim of this study was to find out how many patients after a total laryngectomy (TLE) return to work successfully and what factors support vocational rehabilitation.Laryngectomees (n=231) aged up to 60 years completed questionnaires and structured interviews before TLE (t1), before rehabilitation (t2), at the end of rehabilitation (t3), 1 year after TLE (t4), 2 years after TLE (t5), and 3 years after TLE (t6).Prior to TLE, 38% of all respondents were employed, 34% were unemployed, 23% received disability-related and 3% age-related pension retirement. One year after TLE, 13% were employed, 15% 2 years and 14% 3 years after TLE. Unemployed were 10% (t4), 5% (t5), and 7% (t6) of the patients. For 59% of all respondents it was very important to have a job. Predictors of successful vocational rehabilitation were employment prior to TLE, age <50 years, being self-employed or clerical employee, good physical functioning, good speech intelligibility, high motivation to go back to work, and support from colleagues.Only few laryngectomees return to work. However, even before TLE only a third of the patients was employed, another third was unemployed. Most of the patients receive pension retirement after TLE. As return to work is important for many patients, patient consultations should consider possibilities to support vocational rehabilitation before offering to apply for retirement. PMID:23709161

Singer, S; Keszte, J; Dietz, A; Kluge, A; Plontke, S; Heim, M; J Vogel, H; Matthäus, C; Oeken, J; Breitenstein, K; Koscielny, S; Pabst, F; Schock, J; Eichhorn, T; Meister, E; Mehnert, A; Meyer, A

2013-05-24

240

Complex primary total hip arthroplasty.  

PubMed

Although total hip arthroplasty is now a classic procedure that is well controlled by orthopedic surgeons, some cases remain complex. Difficulties may be due to co-morbidities: obesity, skin problems, muscular problems, a history of neurological disease or associated morphological bone deformities. Obese patients must be informed of their specific risks and a surgical approach must be used that obtains maximum exposure. Healing of incisions is not a particular problem, but adhesions must be assessed. Neurological diseases may require tenotomy and the use of implants that limit instability. Specific techniques or implants are necessary to respect hip biomechanics (offset, neck-shaft angle) in case of a large lever arm or coxa vara. In case of arthrodesis, before THA can be performed, the risk of infection must be specifically evaluated if the etiology is infection, and the strength of the gluteal muscles must be determined. Congenital hip dysplasia presents three problems: the position and coverage of the cup, placement of a specific or custom made femoral stem, with an osteotomy if necessary, and finally lowering the femoral head into the cup by freeing the soft tissues or a shortening osteotomy. Acetabular dysplasia should not be underestimated in the presence of significant bone defect (BD), and reconstruction with a bone graft can be proposed. Sequelae from acetabular fractures presents a problem of associated BD. Internal fixation hardware is rarely an obstacle but the surgical approach should take this into account. Treatment of acetabular protrusio should restore a normal center of rotation, and prevent recurrent progressive protrusion. The use of bone grafts and reinforcement rings are indispensible. Femoral deformities may be congenital or secondary to trauma or osteotomy. They must be evaluated to restore hip biomechanics that are as close to normal as possible. Fixation of implants should restore anteversion, length and the lever arm. Most problems that can make THA a difficult procedure may be anticipated with proper understanding of the case and thorough preoperative planning. PMID:23375960

Boisgard, S; Descamps, S; Bouillet, B

2013-02-01

241

Cementless total hip arthroplasty in patients with osteonecrosis after kidney transplantation.  

PubMed

This study was to determine the mid- to long-term survivorship of cementless metal-on-metal THA in 52 patients (74 hips) who underwent THA for osteonecrosis of the femoral head with a cementless THA. The mean follow-up was 10.2 years. The mean age at operation was 42.1 years (range, 25-62 years). The survivorship analysis with revision as the end point estimated a 96.6% chance of THA survival during 16.4 years. The average Harris hip score at last follow-up was 89.2 points (range, 74-100). Two patients (two hips) required revision surgery for extensive acetabular osteolysis at 9 years and acetabular liner dissociation at 2 years. The survival rates of cementless THA in these patients are encouraging. However, the possibility of metallic wear related complications are raising concern. PMID:23498872

Chang, Jae-Suk; Han, Duck Jong; Park, Su-Kil; Sung, Jung-Hwan; Ha, Yong-Chan

2013-03-14

242

The role of biomechanics and engineering in total hip replacement. Why surgeons need technical help.  

PubMed

Implanting the acetabular cup of hard-on-hard bearings, like metal-on-metal or ceramic-on-ceramic, requires considerable surgeon skill to avoid the complications associated with edge loading. Successful cup positioning instruments have been designed in the past by pioneering surgeons, like Peter Ring and Michael Freeman, and these are re-visited in this article. An advantage of these instruments is that they could position the acetabular cup without defining a reference pelvic plane. Computer-assisted cup orientation is able to reduce outliers in cup orientation, but the technology has not been widely adopted. There may be an opportunity to improve the uptake of computer-assisted surgery by incorporating some of the concepts from historically successful manual instruments. PMID:23636958

Jeffers, Jonathan R T

2012-05-09

243

Increasing Productivity Through Total Reuse Management (TRM).  

National Technical Information Service (NTIS)

Total Reuse Management (TRM) is a new concept currently being promoted by the NASA Langley Software Engineering and Ada Lab (SEAL). It uses concepts similar to those promoted in Total Quality Management (TQM). Both technical and management personnel are c...

M. P. Schuler

1991-01-01

244

Total Quality Management: Time for a Theory.  

National Technical Information Service (NTIS)

The paper states that Total Quality is a goal that requires Quality Leadership to be reached. Important elements in what is called Total Quality Management are; Quality innovation, -maintenance, and -improvement. TQM is carried out through: (1) New norms ...

A. Aune

1991-01-01

245

75 FR 22418 - FHA TOTAL Mortgage Scorecard  

Federal Register 2010, 2011, 2012, 2013

...FR-5376-N-28] FHA TOTAL Mortgage Scorecard AGENCY: Office of the Chief Information...writing for loss of privilege to use the scorecard. DATES: Comments Due Date: May 28...Title of Proposal: FHA TOTAL Mortgage Scorecard. OMB Approval Number:...

2010-04-28

246

Benthic respiration measured by total carbonate production  

Microsoft Academic Search

Abstract The suitability of total carbonate production,instead of oxygen consumption,as a measure,of benthic respiration has been investigated. In situ fluxes of total carbonate, oxygen, calcium, total alkalinity, nutrients, and sulfide across the sediment-water interface were measured in diver- operated benthic flux chambers. Two chambers,were run in parallel to test the influence of oxygen and pH levels on total carbonate production.

LEIF G. ANDERSON; PER O. J. HALL; ÅKE IVERFELDT; MICHIEL M. RUTGERS VAN DER LOEFF; BJØRN SUNDBY; STIG F. G. WESTERLUND

1986-01-01

247

Rise of total pressure in frictional flow  

NASA Astrophysics Data System (ADS)

Examination of total pressure transport equation derived from Navier-Stokes equation reputed the assumption that total pressure can only decrease everywhere in frictional flow. Two classical flow cases with exact solutions demonstrated the local rise in total pressure due to stress application through the mechanical energy redistribution mechanism. The observed proportionality of the rise in total pressure with viscosity implied the capability of total pressure to increase more effectively in turbulent flows than in laminar flows due to higher effective viscosity and stress.

Issa, R. I.

1995-04-01

248

Effect of microstructure on the dry sliding friction behavior of CoCrMo alloys used in metal-on-metal hip implants.  

PubMed

The microstructure and its effect on the friction behavior of a medical grade wrought cobalt-chromium-molybdenum (CoCrMo) alloy for surgical implants were studied in this work. In particular, the effects of compression and carbon (C) content on the above characteristics were analyzed. Increasing amounts of deformation resulted in a decrease in the number of annealing twins in the microstructures. In addition, there was an increase in the volume fraction of the hexagonal closed-packed (HCP) phase due to a strain-induced transformation (SIT) from the metastable face-centered cubic (FCC) phase. The high C (HC) alloy had a lower volume fraction of this SIT phase. Friction studies conducted on these alloys revealed a higher coefficient of friction for the HC alloy and no significant effect of SIT on the friction characteristics. PMID:16080175

Varano, R; Bobyn, J D; Medley, J B; Yue, S

2006-02-01

249

Interactive effects of binary combinations of manganese with other heavy metals on metal uptake and antioxidative enzymes in Brassica juncea L. seedlings  

Microsoft Academic Search

The present study investigates the interactive mechanism involved during the uptake of heavy metals and stress tolerance in Brassica juncea L. seedlings under the influence of Mn(II) in binary combinations with Cr(VI), Ni(II), Co(II) and Cu(II) in terms of changes in antioxidative enzymes-superoxide dismutase (SOD), guaiacol peroxidase (GPX), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR). The order of

Rupinder Kaur; Renu Bhardwaj; Ashwani K. Thukral; Upma Narang

2011-01-01

250

Development of a Routine Method for the Determination of Trace Metals in Whole Blood by Magnetic Sector Inductively Coupled Plasma Mass Spectrometry with Particular Relevance to Patients with Total Hip and Knee Arthroplasty  

Microsoft Academic Search

Background: Joint-replacement surgery has revolution- ized the treatment of osteoarthritis and is still the most effective therapy. A recent clinical trend reintroducing metal-on-metal bearing surfaces has in turn stimulated a requirement for accurate measurement of the concentra- tions of relevant metals in both pre- and postoperative patients. Thus, there is a need for cost-effective, mul- tielement methods for trace metal

C. Patrick Case; Lyndon Ellis; Justine C. Turner; Ben Fairman

251

Free radical scavenging activity, total phenolic content, total antioxidant status, and total oxidant status of endemic Thermopsis turcica.  

PubMed

Thermopsis turcica, endemic to Turkey, is in danger of extinction. Studies on this species are very few due to the fact that it was only discovered in 1983 and grows in a small circumscribed area in Turkey. In this study, free radical scavenging activity, total phenolic content, total oxidant status (TOS), and total antioxidant status (TAS) of methanol (TTM) and acetone (TTA) extracts of T. turcica were measured spectroscopically. Free radical scavenging activity was determined according to the elimination of DPPH radicals and total phenol content was determined by the Folin-Ciocalteu reaction. Total oxidant status (TOS) and total antioxidant status (TAS) were measured with commercially available kits. Methanol and acetone extracts of T. turcica were found to have a specific radical scavenging effect. This effect was found to be related to the total phenolic content of the extracts. Since the TTA had a higher phenolic content than the methanol extract, it had a stronger radical scavenging effect. In addition, the total antioxidant capacity of the methanol extract was observed to be higher than that of its acetone counterpart. As a result, due to its antioxidative properties, T. turcica is thought to be a natural source of antioxidants. PMID:23961240

Aksoy, Laçine; Kolay, Erdi; A??lönü, Yasin; Aslan, Zeyneb; Karg?o?lu, Mustafa

2013-02-20

252

Free radical scavenging activity, total phenolic content, total antioxidant status, and total oxidant status of endemic Thermopsis turcica  

PubMed Central

Thermopsis turcica, endemic to Turkey, is in danger of extinction. Studies on this species are very few due to the fact that it was only discovered in 1983 and grows in a small circumscribed area in Turkey. In this study, free radical scavenging activity, total phenolic content, total oxidant status (TOS), and total antioxidant status (TAS) of methanol (TTM) and acetone (TTA) extracts of T. turcica were measured spectroscopically. Free radical scavenging activity was determined according to the elimination of DPPH radicals and total phenol content was determined by the Folin–Ciocalteu reaction. Total oxidant status (TOS) and total antioxidant status (TAS) were measured with commercially available kits. Methanol and acetone extracts of T. turcica were found to have a specific radical scavenging effect. This effect was found to be related to the total phenolic content of the extracts. Since the TTA had a higher phenolic content than the methanol extract, it had a stronger radical scavenging effect. In addition, the total antioxidant capacity of the methanol extract was observed to be higher than that of its acetone counterpart. As a result, due to its antioxidative properties, T. turcica is thought to be a natural source of antioxidants.

Aksoy, Lacine; Kolay, Erdi; Ag?lonu, Yasin; Aslan, Zeyneb; Karg?oglu, Mustafa

2013-01-01

253

Perfect and total altruism across the generations  

Microsoft Academic Search

The traditional formulation of the altruism model has altruistic terms that relate solely to other parties’ felicities from\\u000a consumption. But if those others are altruistic as well, their altruism benefits are being neglected. Total altruism takes the total utilities of others, rather than their mere felicities, as the basis for altruistic valuations. We assess\\u000a total altruism in an intergenerational world.

Stephen Fels; Richard Zeckhauser

2008-01-01

254

Sports Activity After Total Hip Resurfacing  

Microsoft Academic Search

Background: Little is known about sports activity after total hip resurfacing.Hypothesis: Patients undergoing total hip resurfacing can have a high level of sports activity.Study Design: Case series; Level of evidence, 4.Methods: The authors evaluated the level of sports activities with a standardized questionnaire in 138 consecutive patients (152 hips) 2 years after total hip resurfacing. Range of motion, Harris hip

Marc Banerjee; Bertil Bouillon; Carolin Banerjee; Holger Bäthis; Rolf Lefering; Miriam Nardini; Joachim Schmidt

2010-01-01

255

Method performance study for total solids and total fat in coconut milk and products  

Microsoft Academic Search

Many analytical methods are available for total solids and total fat in various kinds of food. However, none is specific for coconut milk and products. The aim of this study was to establish methods and to conduct the method performance study on determination of total solids and total fat in coconut milk and products. In the single laboratory study, three

Niphaporn Lakshanasomya; Arunee Danudol; Tipawan Ningnoi

2011-01-01

256

Image-guided total marrow and total lymphatic irradiation using helical tomotherapy  

Microsoft Academic Search

Purpose: To develop a treatment technique to spare normal tissue and allow dose escalation in total body irradiation (TBI). We have developed intensity-modulated radiotherapy techniques for the total marrow irradiation (TMI), total lymphatic irradiation, or total bone marrow plus lymphatic irradiation using helical tomotherapy. Methods and Materials: For TBI, we typically use 12 Gy in 10 fractions delivered at an

Timothy E.. Schultheiss; Jeffrey Wong; An Liu; Gustavo Olivera; George Somlo

2007-01-01

257

Treatment of instability after total elbow arthroplasty.  

PubMed

Instability after total elbow arthroplasty can be due to incorrect component selection or position, inadequacy of the medial or lateral ligaments or triceps tendon, polyethylene wear, limb malalignment, or trauma. Patients with significant loss of bone structure, ligament deficiency, and tendon deficiency around the elbow are at increased risk of instability following total elbow arthroplasty. PMID:11689380

O'Driscoll, S W; King, G J

2001-10-01

258

Total light absorption in plasmonic nanostructures  

Microsoft Academic Search

A simple physical model describing the optical properties of a metallic nanostructure in terms of the equivalent oscillating-current resonant circuit, which explains the total light absorption phenomenon in different plasmonic nanostructures on the same basis is presented. It was concluded that total light absorption results from matching the free-space impedance to the surface impedance of the nanostructure at the plasmon

T. V. Teperik; J. F. G. de Abajo; V. V. Popov

2007-01-01

259

CONICAL PLASTIC SCINTILLATORS SHOW TOTAL GAMMA ABSORPTION  

Microsoft Academic Search

Total photon absorption, at least with low energy gamma and x rays, ; was observed in plastic scintillators. The best results were obtained with lead-; loaded, conically-shaped scintillators surrounded by aluminuru oxide as a ; reflector. Low energy photons gave better absorption curves even poorer ; resolution than the higher energy photons. The best stintillation size for total ; absorption

G. J. Hine; J. A. Cardarelli

1960-01-01

260

Chinese cultural values and total quality climate  

Microsoft Academic Search

In view of the scarcity of studies on the relationship between national culture and total quality management (TQM), this paper examines the impact of Chinese cultural values on the total quality climate. Using a sample of 189 ISO 9000 certified companies in Taiwan, results from structural equation modeling indicate that Chinese cultural values do have a positive and statistically significant

Carlos Noronha

2002-01-01

261

Creating the Total Quality Effective School.  

ERIC Educational Resources Information Center

|This book shows how Deming's Total Quality Management (TQM) theory for organizational management can be integrated with the effective-schools literature. Part 1 compares the 14 principles of TQM with the tenets of effective-schools research. The second part develops a blueprint for creating the total quality effective school. The conceptual…

Lezotte, Lawrence W.

262

Total Army Quality: TQM or Something Else.  

National Technical Information Service (NTIS)

The Army has been directed by the Department of Defense (DOD) to change corporate management philosophy and practices by adopting Total Quality Management (TQM) as espoused by W. Edwards Deming and others. Total Army Quality (TAQ) is the Army's new manage...

R. R. Murfin

1993-01-01

263

Weather biases in the NFL totals market  

Microsoft Academic Search

I examine outcome predictability in the National Football League totals betting market using data from the 1984 through 2004 seasons. Results suggest that while weather is an important determinant of scoring, the market does not accurately incorporate the effects of adverse conditions into totals bet prices. Specifically, I demonstrate that heat, wind and rain reduce point production, and provide evidence

Richard Borghesi

2008-01-01

264

EVALUATION OF TOTAL ORGANIC EMISSIONS ANALYSIS METHODS  

EPA Science Inventory

The rationale and supporting experimental data for revising EPA's 1996 "Guidance for Total Organics" are summarized in this document. It reports the results of reseach and investigation of improvements to the Total Organic Emissions (TOE) guidance used by EPA to measure recovera...

265

Prodromes of failure in total knee arthroplasty  

Microsoft Academic Search

A total of 102 revision total knee arthroplasties (TKAs) were reviewed to determine the prodromal symptoms and radiographic findings associated with failure. Presenting symptoms included pain (84%); swelling (76%); progressive varus or valgus deformity (19%); instability (17%); stiffness (17%); clicking or grinding (7%); catching (4%); and patellar pain, subluxation, or clicking (4%). Radiographs were diagnostic in 91% of cases, demonstrating

Jess H. Lonner; John M. Siliski; Richard D. Scott

1999-01-01

266

Immune Modulation after Total Hip Surgery  

Microsoft Academic Search

Background: Major trauma affects the immune system, and immunosuppression may render the patients susceptible to septic complications. The purpose of this study was to investigate lipopolysaccharide (LPS)-induced releases of tumor necrosis factor-? (TNF-?) and interleukin-6 (IL-6) in whole blood in patients undergoing total hip replacement. Methods: Seven patients (6 females) who underwent elective total hip replacement were included. Ex vivo

D. Bastian; J. Sun; C. Danckert Krohn; O. Reikerås

2007-01-01

267

Total Quality and the Human Resource Professional  

Microsoft Academic Search

Interest in the total quality concept has been gaining considerable momentum within North America. Total quality, which is founded on the belief that organizations can succeed by meeting the needs of their customers, has traditionally been a concern of line management. However, specialists in the area of human and industrial relations have been espousing some of the concepts touted by

Fred Palumbo; Bradley S. O’Hara; Paul A. Herbig

1994-01-01

268

The TQM extension: Total customer relationship management  

Microsoft Academic Search

From reviewing literature pertaining to customer relationship management (CRM), most research has focused partially on profitable customers, customer segmentation, information technology, or value creation. Curry and Kkolou (2004) found that CRM has revealed many aspects that closely resemble the total quality management (TQM) approach. A comprehensive viewpoint put forward in this study is going to propose a concept of ‘total

Chun-Hsien Su; August Tsai; Chu-Ling Hsu

2010-01-01

269

Total kinetic energy of an electromagnetic body†  

Microsoft Academic Search

It is here proposed to extend the notion of the kinetic energy of a moving and deformable electromagnetic material. This extended form of kinetic energy, which we suggest naming total kinetic energy, is consistent with the classical expression of the kinetic energy, to which it reduces in the absence of electromagnetic fields. The proposed expression of the total kinetic energy

C. Trimarco

2005-01-01

270

Total recall: are privacy changes inevitable?  

Microsoft Academic Search

Total Recall is a system that records an individual perspective of the world using personal sensors such as a microphone in a pair of glasses or a camera in a necklace. There are many applications of Total Recall -- patients accurately recording what they've recently eaten, students replaying any part of a class, and so on--that can significantly improve people's

William C. Cheng; Leana Golubchik; David G. Kay

2004-01-01

271

Total colonic aganglionosis: 30 years' experience  

Microsoft Academic Search

Thirty-two patients with total colonic aganglionosis (TCA) were seen in 30 years, representing 10% of the total number with aganglionosis seen during that period (1954–1983). The mortality rate was 45%, but has shown a progressive decrease from 82% in the first decade to 9% in the last. The improvement is specifically related to earlier diagnosis, control of sepsis, and the

Daniel T. Cass; Nate Myers

1987-01-01

272

Laparoscopic Total Mesorectal Excision for Rectal Cancers  

Microsoft Academic Search

\\u000a Introduction  More and more colorectal surgeons believe that total mesorectal excision can achieve favorable oncologic results for the treatment\\u000a of rectal cancers. The present study is a feasibility study aiming to evaluate if total mesorectal excision can be safely\\u000a performed by laparoscopic approach with beneficial functional recovery.\\u000a \\u000a \\u000a \\u000a Methods  A total of 44 patients (from January 2004 to February 2005) with middle rectal

Jin-Tung Liang; Horng-Shiee Lai; Po-Huang Lee

2006-01-01

273

UNDERSTANDING CHILDREN'S TOTAL DIETARY EXPOSURE TO PESTICIDES  

EPA Science Inventory

Recent residential monitoring studies have demonstrated that significant portion of total exposure of infants and children to environmental contaminants can result from contamination of food in the home. Children's foods become contaminated through handling and contact with surf...

274

Total Synthesis of the L-Hexoses  

Microsoft Academic Search

Enantiomerically pure polyhydroxylated natural products are synthesized by using a reiterative two-carbon extension cycle consisting of four steps. The generality and efficiency of this methodology are demonstrated in the total synthesis of all eight L-hexoses.

Soo Y. Ko; Albert W. M. Lee; Satoru Masamune; Lawrence A. Reed; K. Barry Sharpless; Frederick J. Walker

1983-01-01

275

Significant total mass contained in small glaciers  

NASA Astrophysics Data System (ADS)

A single large glacier can contain hundreds of millions of times the mass of a small glacier. Nevertheless, small glaciers are so numerous that their contribution to the world's total ice volume is significant and may be a notable source of error if excluded. With current glacier inventories, total volume errors on the order of 10 % are possible at both global and regional scales. However, errors of less than 1 % require glaciers that are smaller than those available in some inventories. Such accuracy requires a global list of all glaciers and ice caps (GIC) as small as 1 km2, and for regional estimates requires substantially smaller sizes. For some regions, volume errors of less than 5 % require a complete list of all glaciers down to the smallest conceivable sizes. For this reason, sea-level rise estimates and other total mass and total volume analyses cannot ignore the world's smallest glaciers without careful justification.

Bahr, D. B.; Radi?, V.

2012-02-01

276

Total lymphoid irradiation in alloimmunity and autoimmunity  

SciTech Connect

Total lymphoid irradiation has been used as an immunosuppressive regimen in autoimmune disease and organ transplantation. The rationale for its use originated from studies of patients with Hodgkin disease, in whom this radiotherapy regimen was noted to induce profound and long-lasting immune suppression and yet was well tolerated, with few long-term side effects. Total lymphoid irradiation is a unique immunosuppressive regimen that produces a selective (and long-lasting) reduction in the number and function of helper T cells and certain subsets of B cells. Conventional immunosuppressive drugs show little selectivity, and their effects are short-lived. The most important aspect of total lymphoid irradiation is the potential for achieving transplantation tolerance and permanent remissions in autoimmune disease in laboratory animals. Attempts are being made to achieve similar goals in humans given total lymphoid irradiation, so that immunosuppressive drugs can be ultimately withdrawn from transplant recipients and patients with lupus nephritis. 28 references.

Strober, S.

1987-12-01

277

Total Diet Study - Analytical Determination Steps, Pesticides ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... Food. ... Total Diet Study - Analytical Determination Steps, Pesticides and Industrial Chemicals. CFSAN/Office of Plant and Dairy Foods and Beverages ... More results from www.fda.gov/food/foodscienceresearch/totaldietstudy

278

Sediment Total Maximum Daily Loads (TMDLs) Glossary  

EPA Pesticide Factsheets

Water Quality:  The biological, chemical, and physical conditions of a waterbody. It is a measure of a waterbody's ability to support beneficial uses.   From Sediment Total Maximum Daily Loads (TMDLs) Glossary  -  Search all glossaries for terms containing water quality

2012-12-10

279

Salmonella infection of a total knee replacement.  

PubMed

Salmonella enterica serotype Choleraesuis is a rare infective pathogen in total knee arthroplasty and accounts for less than 1% of all cases. In the United Kingdom, the most prevalent organisms are Staphylococci, which account for over 50% of cases. We present an interesting case report of an infected revision total knee replacement following foreign travel to a region with an increased prevalence of Salmonella. The patient presented typically with an effused knee and raised inflammatory markers. Tissue samples demonstrated Salmonella choleraesuis as the infective organism. Though this serotype has previously been isolated from an infected total hip prosthesis, we believe this could be the first reported case involving a total knee replacement. Following involvement of our microbiology team and aggressive antibiotic therapy, the patient was successfully treated with two-stage revision surgery and at one-year post-op is making a satisfactory recovery. PMID:19897369

Carlile, G S; Elvy, J; Toms, A D

2009-11-07

280

NASA Total Quality Management 1989 Accomplishments Report.  

National Technical Information Service (NTIS)

The document describes the accomplishments made by NASA in Total Quality Management. The principles in practice which led to these process refinements are important cultural elements to any organization's productivity and quality efforts. The catagories i...

1990-01-01

281

The Physics Classroom: Total Internal Reflection  

NSDL National Science Digital Library

This Physics Classroom article explains the concept of Total Internal Reflection. The text is accompanied by helpful diagrams. This page is part of a larger Physics Classroom lesson on the Ray Model of Light.

2010-09-17

282

Farm Family Total Noise Exposure Assessment.  

National Technical Information Service (NTIS)

A pilot project was conducted to evaluate occupational and non-occupational noise exposures of three families living and working on farms in Northwest Ohio during planting season, growing season, and harvesting season. A total of nine family members (six ...

J. R. Wilkins S. Khuder S. A. Milz

2007-01-01

283

Bilateral total renal dysplasia: a case report.  

PubMed

Bilateral total renal dysplasia is an extremely rare congenital anomaly associated with Potter's facies. We report an autopsy case of a stillborn male child. Histopathology is showing persistence of structures not seen in normal development. PMID:15471131

Zawar, M P; Kurdukar, M D; Mashal, S N; Inamdar, J S

2004-01-01

284

Outdoor Activities for a Total Lunar Eclipse  

ERIC Educational Resources Information Center

Describes several activities involving a total eclipse of the moon. Included are observations with binoculars, naked eye, and telescope; timing activities and observations of color changes during penumbral and umbral phases; and photography activities. (CS)

Glenn, William H.

1977-01-01

285

Total Performance Management: Some Pointers for Action.  

National Technical Information Service (NTIS)

Total Performance Management (TPM) is described, and the conditions for a successful program are discussed along with a nine - step procedure for implementing the program based on the experiences of four jurisdictions. TPM integrates employee feedback, pr...

1978-01-01

286

Enantioselective Total Synthesis of (+)-Gliocladin C  

PubMed Central

The first total synthesis of gliocladin C, a fungal-derived marine alkaloid containing a rare trioxopiperazine fragment, is reported. This asymmetric synthesis establishes the absolute configuration of this structurally novel natural product.

Overman, Larry E.; Shin, Youseung

2008-01-01

287

Computerized roentgenographic determination of total lung capacity.  

PubMed

A computerized technique for measuring total lung capacity from radiographic chest films based on methods originally suggested by Barnhard and associates has been developed. Total lung capacity is automatically determined by tracing the margins of the lungs in both posteroanterior and lateral radiographs with a commercially available hypersonic coordinate digitizer. The results compare favorably with those obtained using a body plethysmograph. This simple, automatic procedure requires minimal training, is rapid, and can be easily implemented. PMID:1247238

Barret, W A; Clayton, P D; Lambson, G R

1976-02-01

288

Effects of xenobiotics on total antioxidant capacity  

PubMed Central

The objective of this article was to review the effects of xenobiotics on total antioxidant capacity (TAC). Measurement of TAC is appropriate for evaluation of the total antioxidant defenses of blood, cells, and different kinds of tissues and organs. TAC is reduced by alcoholism, smoking, and exposure to radiation, herbicides, carbon monoxide, carbon tetrachloride, lead, arsenic, mercury, cadmium, aluminum, and other toxic elements. The test is also an important tool in evaluating environmental and occupational exposure.

2012-01-01

289

A solar\\/Stirling total energy system  

Microsoft Academic Search

A conceptual design of a solar-powered Stirling engine-driven total energy system (TES) is presented. Analysis results are given for a demonstration system which would supply the total energy needs of an advanced concept multi-unit residential complex. The concept also has application to commercial buildings, schools, hospitals, and shopping centers. The system is designed to make maximum use of Stirling automotive

R. L. Pons; R. J. Fox

1976-01-01

290

Asymmetric, stereocontrolled total synthesis of paraherquamide A.  

PubMed

The first total synthesis of paraherquamide A, a potent anthelmintic agent isolated from various Penicillium sp. with promising activity against drug-resistant intestinal parasites, is reported. Key steps in this asymmetric, stereocontrolled total synthesis include a new enantioselective synthesis of alpha-alkylated-beta-hydroxyproline derivatives to access the substituted proline nucleus and a highly diastereoselective intramolecular S(N)2' cyclization to generate the core bicyclo[2.2.2]diazaoctane ring system. PMID:14519003

Williams, Robert M; Cao, Jianhua; Tsujishima, Hidekazu; Cox, Rhona J

2003-10-01

291

Effects of xenobiotics on total antioxidant capacity.  

PubMed

The objective of this article was to review the effects of xenobiotics on total antioxidant capacity (TAC). Measurement of TAC is appropriate for evaluation of the total antioxidant defenses of blood, cells, and different kinds of tissues and organs. TAC is reduced by alcoholism, smoking, and exposure to radiation, herbicides, carbon monoxide, carbon tetrachloride, lead, arsenic, mercury, cadmium, aluminum, and other toxic elements. The test is also an important tool in evaluating environmental and occupational exposure. PMID:23554550

Ferrari, Carlos Kusano Bucalen

2012-09-01

292

Total Body Irradiation before Bone Marrow Transplantation  

Microsoft Academic Search

Purpose: To evaluate the total body irradiation methods in the National Institute of Oncology between January 1984 and February 1998. Patients and Method: One hundred and twenty-four patients underwent total body irradiation prior to bone marrow transplantation in the last 15 years. A special cobalt unit has been used, the dose rate was 6 to 8 cGy\\/min in the midline

Judit Székely; László Fábry; Gyula Forgács; Gábor Kontra; Julia Petrányi; Olga Ésik; György Németh

1999-01-01

293

Total OH reactivity emissions from Norway spruce  

NASA Astrophysics Data System (ADS)

Forest emissions represent a strong potential sink for the main tropospheric oxidant, the hydroxyl radical (OH). In forested environments, the comparison of the directly determined overall sink of OH radicals, the total OH reactivity, and the individually measured OH sink compounds often exposes a significant gap. This "missing" OH reactivity can be high and influenced by both direct biogenic emissions and secondary photo-oxidation products. To investigate the source of the missing OH sinks in forests, total OH reactivity emission rates were determined for the first time from a Norway spruce (Picea abies) throughout spring, summer and autumn 2011. The total OH reactivity was measured inside a branch enclosure using the Comparative Reactivity Method (CRM) with a Proton Transfer Reaction-Mass Spectrometer (PTR-MS) as the detector. In parallel, separate volatile organic compounds (VOC) emission rates were monitored by a second PTR-MS, including the signal of isoprene, acetaldehyde, total monoterpenes and total sesquiterpenes. The comparison of known and PTR-MS detected OH sink compounds and the directly measured total OH reactivity emitted from Norway spruce revealed unmeasured and possibly unknown primary biogenic emissions. These were found to be highest in late summer during daytime coincident with highest temperatures and ozone levels.

Nölscher, Anke; Bourtsoukidis, Efstratios; Bonn, Boris; Kesselmeier, Jürgen; Lelieveld, Jos; Williams, Jonathan

2013-04-01

294

Evaluation of the Technicon Block Digestor System for Total Kjeldahl Nitrogen and Total Phosphorus.  

National Technical Information Service (NTIS)

Technicon's block digestor method for the simultaneous determination of total phosphorus and total Kjeldahl nitrogen has been evaluated and modified for the semi-automated determination of these constituents in surface water and domestic and industrial wa...

M. E. Gales R. L. Booth

1978-01-01

295

Simultaneous and Automated Determination of Total Phosphorus and Total Kjeldahl Nitrogen.  

National Technical Information Service (NTIS)

Milbury's method for the simultaneous determination of total phosphorus and total Kjeldahl nitrogen (TKN) in activated sludge has been modified for the automated determination of these constituents in surface waters, domestic and industrial wastes. Modifi...

M. E. Gales R. L. Booth

1974-01-01

296

EVALUATION OF THE TECHNICON BLOCK DIGESTOR SYSTEM FOR TOTAL KJELDAHL NITROGEN AND TOTAL PHOSPHORUS  

EPA Science Inventory

Technicon's block digestor method for the simultaneous determination of total phosphorus and total Kjeldahl nitrogen has been evaluated and modified for the semi-automated determination of these constituents in surface water and domestic and industrial wastes. The Technicon diges...

297

Totally semi-continuous and semi totally-continuous functions in double fuzzy topological spaces  

NASA Astrophysics Data System (ADS)

The aim of this paper is to introduce new classes of functions called totally-continuous functions and its variants totally semi-continuous functions and semi totally-continuous functions in double fuzzy topological spaces. Their characterizations, examples and relationship with other notions of continuous functions in this space are provided.

Mahmood Mohammed, Fatimah; Md Noorani, Mohd Salmi; Salleh, Abdul Razak

2013-04-01

298

The US 2017 Total Solar Eclipse Workshops  

NASA Astrophysics Data System (ADS)

In preparation for the Total Solar Eclipse that will span across the United States in 2017, multiple eclipse workshops are being planned to bring together professional and amateur researchers, educators, and imagers. Our ultimate goal with these workshops is to maximize the amount and quality of data we can collect during the eclipse as well as to leverage this exciting event to educate and inspire people of all ages. Part of the workshops will be dedicated to discussing the science that can be learned from observing total solar eclipses, and part of the workshops will be dedicated to strategizing about how to mobilize and prepare communities in the path of totality. In this poster, we will share our preliminary results from the inaugural workshop in Maryland, April 2012.

Arndt, Martina B.; Habbal, S. R.; Wind Sherpas, Solar

2012-05-01

299

KP solitons, total positivity, and cluster algebras  

PubMed Central

Soliton solutions of the KP equation have been studied since 1970, when Kadomtsev and Petviashvili [Kadomtsev BB, Petviashvili VI (1970) Sov Phys Dokl 15:539–541] proposed a two-dimensional nonlinear dispersive wave equation now known as the KP equation. It is well-known that the Wronskian approach to the KP equation provides a method to construct soliton solutions. The regular soliton solutions that one obtains in this way come from points of the totally nonnegative part of the Grassmannian. In this paper we explain how the theory of total positivity and cluster algebras provides a framework for understanding these soliton solutions to the KP equation. We then use this framework to give an explicit construction of certain soliton contour graphs and solve the inverse problem for soliton solutions coming from the totally positive part of the Grassmannian.

Kodama, Yuji; Williams, Lauren K.

2011-01-01

300

Total solar eclipse of 1997 March 9  

NASA Astrophysics Data System (ADS)

A total eclipse of the Sun will be visible from Asia and the Pacific Ocean on 1997 March 9. The path of the Moon's umbral shadow begins in eastern Kazakhstan and travels through Mongolia and eastern Siberia, where it swings northward to end at sunset in the Arctic Ocean. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes eastern Asia, the northern Pacific, and the northwest corner of North America. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 280 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

Espenak, Fred; Anderson, Jay

1995-07-01

301

Thyroid tissue remnants after "total thyroidectomy".  

PubMed

Total Thyroidectomy (TT) is a gold standard for benign bilateral pathologies and malignant pathologies of the thyroid. TT has numerous advantages over less radical approaches, such as the resolution of the thyroid pathology, avoidance of recurrences, and improved response to life-long substitutive organotherapy. TT has a negligible rate of recurrence. Near Total Thyroidectomy (NTT) is associated with a low rate of recurrence. Subtotal Thyroidectomy (ST), in which a portion of the thyroid gland is deliberately left in the thyroid lodge, has a considerably higher rate of recurrence. The incidence of complications with TT is similar to that with other techniques of thyroid exeresis. However, despite the radical intent of surgeons, a real TT is not always carried out. The complete removal of all the thyroid tissue employing TT is not the norm and micro/macroscopic remnants almost always remain. The literature on these tissue remnants is often based on techniques that are not very accurate in terms of determining the diameters of the tissue remaining. In our study, conducted by colour echo-doppler of the thyroid lodge in 102 patients who had undergone TT for benign thyroid pathologies, we demonstrated significant thyroid tissue remnants after TT in 34 cases of 102 (33,3%). Therefore, out of a total of 102 so-called "total thyroidectomies", only 68 (66,7%) were really total, whereas 12 patients (11,76%) had near total thyroidectomy, leaving tissue remnants < 1 cm, and 22 patients (21,57%) had subtotal thyroidectomy, with tissue remnants > or = 1 cm. PMID:19735611

D'Andrea, V; Cantisani, V; Catania, A; Di Matteo, F M; Sorrenti, S; Greco, R; Kyriacou, K A; Kyriacos, K; Menichini, G; Marotta, E; De Stefano, M; Palermo, S; Di Marco, C; De Antoni, E

302

[Total ankle replacement for varus deformity].  

PubMed

Coronal plane deformity has been found to be one of the main risk factors for poor clinical results, higher complication rates and failure of total ankle replacements. Initially, many authors considered a malalignment of more than 10° to be a contraindication for total ankle replacement, however, several publications later underlined the usefulness of the distinction of different etiologies of hindfoot malalignment. This subsequently led to suggestions for additional procedures in order to avoid early implant failure.The aim of the present article is to illustrate the different causes of varus malaligned arthritic ankles and to present procedures to balance these ankles at the time of replacement. PMID:22002209

Knupp, M; Bolliger, L; Barg, A; Hintermann, B

2011-11-01

303

Employee benefits in a total rewards framework.  

PubMed

Benefits represent one of the largest investments a company makes in its talent. However, our tendency can be to design, deliver and communicate benefits programs independently, without fully considering how those programs fit within a bigger picture of total rewards. Sure, we need to manage and execute individual benefit programs--but not at the expense of getting a real return on our more significant investment in talent. This article provides employers with perspectives on the value of managing benefits within the broader framework of total rewards, why it works and, most importantly, how to make it work. PMID:23488085

Kwon, Jane; Hein, Pam

2013-01-01

304

Estimating total momentum at finite distances  

SciTech Connect

We study the difficulties associated with the evaluation of the total Bondi momentum at finite distances around the central source of a general (asymptotically flat) spacetime. Since the total momentum is only rigorously defined at future null infinity, both finite distance and gauge effects must be taken into account for a correct computation of this quantity. Our discussion is applicable in general contexts but is particularly relevant in numerically constructed spacetimes for both extracting important physical information and assessing the accuracy of additional quantities.

Gallo, Emanuel; Moreschi, Osvaldo M. [FaMAF Universidad Nacional de Cordoba, Ciudad Universitaria, (5000) Cordoba (Argentina); Lehner, Luis [Department of Physics and Astronomy, LSU, Baton Rouge, Louisiana 70803 (United States)

2008-10-15

305

Total cross section in ?? collisions at LEP  

Microsoft Academic Search

The reaction e+e??e+e??????e+e?hadrons for quasi-real photons is studied using data from s=183 GeV up to 202 GeV. Results on the total cross sections ?(e+e??e+e?hadrons) and ?(???hadrons) are given for the two-photon centre-of-mass energies 5 GeV?W???185 GeV. The total cross section of two real photons is described by a Regge parametrisation. We observe a steeper rise with the two-photon centre-of-mass energy as compared to the

M. Acciarri; P. Achard; O. Adriani; M. Aguilar-Benitez; J. Alcaraz; G. Alemanni; J. Allaby; A. Aloisio; M. G. Alviggi; G. Ambrosi; H. Anderhub; V. P. Andreev; T. Angelescu; F. Anselmo; A. Arefiev; T. Azemoon; T. Aziz; P. Bagnaia; A. Bajo; L. Baksay; A. Balandras; S. V. Baldew; S. Banerjee; A. Barczyk; R. Barillère; P. Bartalini; M. Basile; N. Batalova; R. Battiston; A. Bay; F. Becattini; U. Becker; F. Behner; L. Bellucci; R. Berbeco; J. Berdugo; P. Berges; B. Bertucci; B. L. Betev; S. Bhattacharya; M. Biasini; A. Biland; J. J. Blaising; S. C. Blyth; G. J. Bobbink; A. Böhm; L. Boldizsar; B. Borgia; D. Bourilkov; M. Bourquin; S. Braccini; J. G. Branson; F. Brochu; A. Buffini; A. Buijs; J. D. Burger; W. J. Burger; X. D. Cai; M. Capell; G. Carlino; A. M. Cartacci; J. Casaus; G. Castellini; F. Cavallari; N. Cavallo; C. Cecchi; M. Cerrada; F. Cesaroni; M. Chamizo; Y. H. Chang; U. K. Chaturvedi; M. Chemarin; A. Chen; G. Chen; H. F. Chen; H. S. Chen; G. Chiefari; L. Cifarelli; F. Cindolo; C. Civinini; I. Clare; R. Clare; G. Coignet; N. Colino; S. Costantini; F. Cotorobai; A. Csilling; S. Cucciarelli; T. S. Dai; R. D'Alessandro; P. Déglon; A. Degré; K. Deiters; E. Delmeire; P. Denes; F. DeNotaristefani; M. Diemoz; M. Dierckxsens; C. Dionisi; M. Dittmar; A. Dominguez; A. Doria; M. T. Dova; D. Duchesneau; D. Dufournaud; P. Duinker; A. Engler; F. J. Eppling; F. C. Erné; A. Ewers; P. Extermann; M. Fabre; M. A. Falagan; S. Falciano; A. Favara; J. Fay; O. Fedin; M. Felcini; T. Ferguson; H. Fesefeldt; E. Fiandrini; J. H. Field; F. Filthaut; P. H. Fisher; I. Fisk; G. Forconi; K. Freudenreich; C. Furetta; Yu. Galaktionov; S. N. Ganguli; P. Garcia-Abia; M. Gataullin; S. S. Gau; S. Gentile; N. Gheordanescu; S. Giagu; Z. F. Gong; G. Grenier; O. Grimm; M. W. Gruenewald; M. Guida; V. K. Gupta; A. Gurtu; L. J. Gutay; D. Haas; A. Hasan; D. Hatzifotiadou; T. Hebbeker; A. Hervé; P. Hidas; J. Hirschfelder; H. Hofer; G. Holzner; H. Hoorani; S. R. Hou; Y. Hu; I. Iashvili; B. N. Jin; L. W. Jones; I. Josa-Mutuberr??a; R. A. Khan; D. Käfer; M. Kaur; M. N. Kienzle-Focacci; D. Kim; J. K. Kim; J. Kirkby; D. Kiss; W. Kittel; A. Klimentov; A. C. König; M. Kopal; A. Kopp; V. Koutsenko; M. Kräber; R. W. Kraemer; W. Krenz; A. Krüger; A. Kunin; I. Laktineh; G. Landi; M. Lebeau; A. Lebedev; P. Lebrun; P. Lecomte; P. Lecoq; H. J. Lee; R. Leiste; P. Levtchenko; C. Li; S. Likhoded; C. H. Lin; W. T. Lin; F. L. Linde; L. Lista; Z. A. Liu; W. Lohmann; E. Longo; Y. S. Lu; K. Lübelsmeyer; C. Luci; D. Luckey; L. Lugnier; L. Luminari; W. Lustermann; W. G. Ma; M. Maity; L. Malgeri; A. Malinin; C. Maña; D. Mangeol; J. Mans; G. Marian; J. P. Martin; F. Marzano; K. Mazumdar; R. R. McNeil; S. Mele; L. Merola; M. Meschini; W. J. Metzger; A. Mihul; H. Milcent; G. Mirabelli; J. Mnich; G. B. Mohanty; T. Moulik; G. S. Muanza; A. J. M. Muijs; B. Musicar; M. Musy; M. Napolitano; F. Nessi-Tedaldi; H. Newman; T. Niessen; A. Nisati; H. Nowak; R. Ofierzynski; G. Organtini; A. Oulianov; C. Palomares; D. Pandoulas; S. Paoletti; P. Paolucci; R. Paramatti; H. K. Park; I. H. Park; G. Passaleva; S. Patricelli; T. Paul; M. Pauluzzi; C. Paus; F. Pauss; M. Pedace; S. Pensotti; D. Perret-Gallix; B. Petersen; D. Piccolo; F. Pierella; M. Pieri; P. A. Piroué; E. Pistolesi; V. Plyaskin; M. Pohl; V. Pojidaev; H. Postema; J. Pothier; D. O. Prokofiev; J. Quartieri; G. Rahal-Callot; M. A. Rahaman; P. Raics; N. Raja; R. Ramelli; P. G. Rancoita; R. Ranieri; A. Raspereza; G. Raven; P. Razis; D. Ren; M. Rescigno; S. Reucroft; S. Riemann; K. Riles; J. Rodin; B. P. Roe; L. Romero; A. Rosca; S. Rosier-Lees; S. Roth; C. Rosenbleck; B. Roux; J. A. Rubio; G. Ruggiero; H. Rykaczewski; S. Saremi; S. Sarkar; J. Salicio; E. Sanchez; M. P. Sanders; C. Schäfer; V. Schegelsky; S. Schmidt-Kaerst; D. Schmitz; H. Schopper; D. J. Schotanus; G. Schwering; C. Sciacca; A. Seganti; L. Servoli; S. Shevchenko; N. Shivarov; V. Shoutko; E. Shumilov; A. Shvorob; T. Siedenburg; D. Son; B. Smith; P. Spillantini; M. Steuer; D. P. Stickland; A. Stone; B. Stoyanov; A. Straessner; K. Sudhakar; G. Sultanov; L. Z. Sun; S. Sushkov; H. Suter; J. D. Swain; Z. Szillasi; T. Sztaricskai; X. W. Tang; L. Tauscher; L. Taylor; B. Tellili; D. Teyssier; C. Timmermans; Samuel C. C. Ting; S. M. Ting; S. C. Tonwar; J. Tóth; C. Tully; K. L. Tung; Y. Uchida; J. Ulbricht; E. Valente; G. Vesztergombi; I. Vetlitsky; D. Vicinanza; G. Viertel; S. Villa; M. Vivargent; S. Vlachos; I. Vodopianov; H. Vogel; H. Vogt; I. Vorobiev; A. A. Vorobyov; A. Vorvolakos; M. Wadhwa; W. Wallraff; M. Wang; X. L. Wang; Z. M. Wang; A. Weber; M. Weber; P. Wienemann; H. Wilkens; S. X. Wu; S. Wynhoff; L. Xia; Z. Z. Xu; J. Yamamoto; B. Z. Yang; C. G. Yang; H. J. Yang; M. Yang; J. B. Ye; S. C. Yeh; An. Zalite; Yu. Zalite; Z. P. Zhang; G. Y. Zhu; R. Y. Zhu; A. Zichichi; G. Zilizi; B. Zimmermann; M. Zöller

2001-01-01

306

Total synthesis of vineomycin b2.  

PubMed

The first total synthesis of vineomycin B2 (1) has been accomplished. The aglycon segment, a vineomycinone B2 derivative, and the glycon segment, an ?-l-acurosyl-l-rhodinose derivative, were prepared via C-glycosylation using an unprotected sugar and powerful chemoselective O-glycosylation using a 2,3-unsaturated sugar, respectively, as the key steps. Furthermore, effective and simultaneous introduction of the two glycon moieties to the aglycon part by concentration-controlled glycosylation led to the total synthesis of 1. PMID:24074200

Kusumi, Shunichi; Tomono, Satoshi; Okuzawa, Shunsuke; Kaneko, Erika; Ueda, Takashi; Sasaki, Kaname; Takahashi, Daisuke; Toshima, Kazunobu

2013-10-11

307

Total Knee Arthroplasty Considerations in Rheumatoid Arthritis  

PubMed Central

The definitive treatment for advanced joint destruction in the late stages of rheumatoid arthritis can be successfully treated with total joint arthroplasty. Total knee arthroplasty has been shown to be a well-proven modality that can provide pain relief and restoration of mobility for those with debilitating knee arthritis. It is important for rheumatologists and orthopedic surgeons alike to share an understanding of the special considerations that must be addressed in this unique population of patients to ensure success in the immediate perioperative and postoperative periods including specific modalities to maximize success.

Danoff, Jonathan R.; Geller, Jeffrey A.

2013-01-01

308

Asymmetric Total Syntheses of (-)-Variabilin and (-)-Glycinol  

PubMed Central

Total syntheses of (?)-variabilin and (?)-glycinol have been accomplished, using the catalytic, asymmetric “interrupted” Feist-Bénary reaction (IFB) as the key transformation to introduce both stereogenic centers. A monoquinidine pyrimidinyl ether catalyst affords the IFB products in over 90% ee in both cases. Other key steps include an intramolecular Buchwald-Hartwig coupling and a nickel-catalyzed aryl tosylate reduction.

Calter, Michael A.; Li, Na

2011-01-01

309

Total Quality Management: Implications for Internal Audit  

Microsoft Academic Search

Total Quality Management (TQM) will have major implications for the internal audit function. Argues that TQM concepts, such as people empowerment, are incompatible with traditional notions of compliance with prescribed internal controls, policies and procedures. Suggests that the fundamental principles which govern the practice of internal audit are incompatible with TQM environments. Examines a number of scenarios to assess the

Lindsay C. Hawkes; Michael B. Adams

1994-01-01

310

Total Quality Management: Implications for Higher Education.  

ERIC Educational Resources Information Center

|This book contains 19 papers describing the implementation of Total Quality Management in a variety of higher education settings. Following a Foreword by Peter Likins and a Preface by Daniel J. Julius, the chapter titles and authors are: (1) "TQM: Implications for Higher Education--A Look Back to the Future" (Allan M. Hoffman and Randall…

Hoffman, Allan M., Ed.; Julius, Daniel J., Ed.

311

Total synthesis of brevisamide and herboxidiene  

Microsoft Academic Search

Brevisamide is a recently discovered natural product. It is believed to play an important role in the biosynthesis of marine polyether toxins, such as brevenal. We have accomplished an asymmetric total synthesis of brevisamide. The synthesis is convergent and involves the efficient sp2-sp 3 type coupling of fragments via Suzuki reaction. The stereogenic tetrahydropyran ring was synthesized via a highly

Jianfeng Li

2011-01-01

312

Chinese National Strategy of Total War.  

National Technical Information Service (NTIS)

The purpose of this research is to examine the recent trends in the growth of China's national power across all elements to determine if there is an underlying national strategy based on the Chinese concept of total warfare. This research seeks to determi...

M. J. Good

2008-01-01

313

Total synthesis of chaetoquadrins A-C.  

PubMed

The first total synthesis of the monoamine oxidase inhibitors chaetoquadrins A-C has been accomplished. Key steps in the synthesis include an aromatic Claisen rearrangement, asymmetric boron aldol reaction and acid-mediated spiroketalization. Comparison of spectral data for the synthetic spiroketals confirmed the proposed structure for these natural products. PMID:23327616

Kim, U Bin; Furkert, Daniel P; Brimble, Margaret A

2013-01-17

314

Production Function Geometry with "Knightian" Total Product  

ERIC Educational Resources Information Center

|Authors of principles and price theory textbooks generally illustrate short-run production using a total product curve that displays first increasing and then diminishing marginal returns to employment of the variable input(s). Although it seems reasonable that a temporary range of increasing returns to variable inputs will likely occur as…

Truett, Dale B.; Truett, Lila J.

2007-01-01

315

Solar total-energy community project  

Microsoft Academic Search

The concept of a solar total-energy community entails collecting solar ; energy at a central area, converting part of it to electricity, and distributing ; the rest of it to homes and\\/or businesses for space heating or cooling. The ; Sandia Laboratories' concept for such uses of solar energy, its departure from ; other solarenergy approaches, and the development program

Brandvold

1974-01-01

316

Total lymphoid irradiation in renal transplantation  

Microsoft Academic Search

Total lymphoid irradiation (TLI), used in the treatment of some patients with Hodgkin's disease, produces profound immunological changes. In small rodents, mice and rats, a modified version of TLI results in transplantation tolerance for skin and heart allografts. The concept has been expanded to large outbred animals. In baboons transplantation tolerance has been produced for kidney and liver transplantation. The

J. Albertus Myburgh; Jacobus A. Smit; Anthony M. Meyers; J. René Botha; Selma Browde; Peter D. Thomson

1986-01-01

317

Periprosthetic femoral fracture after total hip arthroplast  

Microsoft Academic Search

Periprosthetic femoral fractures represent a significant complication in total hip arthroplasty. based on originand treatment considerations, these fractures are best considered on the basis of the proximal region, and middle region below the lesser trochanter, and distal region at the prosthetic tip and beyond. Proximal-region fractures are usually wired and treated conservatively. Middle-region fractures may require prosthetic revision in addition

James B. Stiehl

1995-01-01

318

Total Quality Management (TQM) in Higher Education.  

ERIC Educational Resources Information Center

This document consists largely of paper versions of the transparencies used by the author to give his conference paper on Total Quality Management (TQM) in the college and university setting. An introduction lists a series of definitional phrases, a list of what TQM is not, and 11 fundamental principles describing what TQM is. The three major…

Sullivan, Michael F.

319

Urinary Total Protein Estimation – Fact or Fiction?  

Microsoft Academic Search

In two recent surveys of urinary total protein assays, 370 laboratories in the United Kingdom were requested to determine the protein content of a simulated 24-hour urine (a solution of sodium and potassium salts and urea, with no added protein) and of a 24-hour urine from a healthy individual. The nature of these specimens was not revealed and participants used

Robin E. Chambers; David G. Bullock; John T. Whicher

1989-01-01

320

URINARY TOTAL ANTIOXIDANT CAPACITY IN SOCCER PLAYERS  

Microsoft Academic Search

Both aerobic and anaerobic exercise contributes to oxidative stress by generation of free radicals. The human body is well equipped with both enzymatic and non-enzymatic antioxidant defence system. Soccer predominantly involves aerobic exercise with repeated bouts of anaerobic activities. The response of the different antioxidants to exercise might be sports-specific and hence the total antioxidant capacity (TAC) provides a better

Swarup Mukherjee; Michael Chia

321

A Campus Is a Total Community.  

ERIC Educational Resources Information Center

Described are the various components of the total college or university community and their associated environmental health and safety problems. Included are food service, insect and rodent control, multi-use athletic facilities, housing, laboratory animal facilities, laboratory biosafety, radiological health, fire protection, and emergency…

Hunt, Robert E.

1979-01-01

322

Total Quality Management in Libraries: A Sourcebook.  

ERIC Educational Resources Information Center

|Total Quality Management (TQM) brings together the best aspects of organizational excellence by driving out fear, offering customer-driven products and services, doing it right the first time by eliminating error, and maintaining inventory control without waste. Libraries are service organizations which are constantly trying to improve service.…

O'Neil, Rosanna M., Comp.

323

Total and Organic Mercury in Marine Fish.  

National Technical Information Service (NTIS)

A study to determine total and organic mercury levels in the muscle tissue of certain pelagic and inshore fish of Hawaii which are used for human consumption is reported. In all species, except the Pacific Blue Marlin, there was close correlation between ...

J. B. Rivers J. E. Pearson C. D. Shultz

1972-01-01

324

The total ozone at mid latitudes  

NASA Astrophysics Data System (ADS)

The total ozone at mid latitudes B.D.Mendeva 1, D.G. Krastev 1, Ts.N.Gogosheva 2 1 Solar Terrestrial Influences Laboratory, Bulgarian Academy of Sciences, Stara Zagora De-partment, Bulgaria, bmendeva@abv.bg 2 Institute of Astronomy, Bulgarian Academy of Sciences, Sofia, Bulgaria, This paper presents the total ozone content (TOC) behaviour over Bulgaria from satellite ex-periments (TOMS on the Earth Probe satellite and SCIAMACHY on board ENVISAT (ESA)). The long-term variations of the total ozone monthly means values in the period 1997-2009 are examined. The calculated linear ozone trend for this time interval is shown. An analysis of the total ozone over the Balkan region is also presented. For this purpose data from the SCIA-MACHY are used. The investigation is made for Athens (37o 59'N, 23o46'E), Thessaloniki (40o31'N, 22o58'E), Sofia (42o39'N, 23o23'E) and Bucharest (44o28'N, 26o17'E) in the period 2003-2009. A comparison between the courses of the monthly mean ozone values over these places is shown.

Mendeva, Bogdana

325

Anterior iliopsoas impingement after total hip arthroplasty  

Microsoft Academic Search

Pain after total hip arthroplasty (THA) can be caused by a multitude of conditions, including infection, aseptic loosening, heterotopic ossification, and referred pain. It is also recognized that soft tissue inflammation about the hip, such as trochanteric bursitis, can lead to hip pain after THA. Two cases of persistent iliopsoas tendinitis following THA are reported, which are believed to be

Robert T. Trousdale; Miguel E. Cabanela; Daniel J. Berry

1995-01-01

326

Design options in solar total energy systems  

Microsoft Academic Search

A solar total energy system consists of a collector field which converts solar radiation to thermal energy in a working fluid which in turn drives a heat engine. Shaft power from this engine drives a mechanical electrical generator while exhaust from the heat engine is used for such applications as space heating, domestic hot water, and process heat. Cooling can

A. A. J. Hoffman; D. Rapp

1977-01-01

327

Total Quality Management, Department of Defense.  

National Technical Information Service (NTIS)

The report is a series of pages that synopsizes the Department of Defense concept of Total Quality Management (TQM). The document includes: How TQM Works; What is TQM; The DoD Vision; TQM Principles; TQM Practices; TQM Techniques and Tools; TQM Implementa...

1988-01-01

328

Total Quality Management (TQM) in Higher Education.  

ERIC Educational Resources Information Center

|This document consists largely of paper versions of the transparencies used by the author to give his conference paper on Total Quality Management (TQM) in the college and university setting. An introduction lists a series of definitional phrases, a list of what TQM is not, and 11 fundamental principles describing what TQM is. The three major…

Sullivan, Michael F.

329

Total Quality Can Help Your District's Image.  

ERIC Educational Resources Information Center

|Describes how educators in the Pearl River School District, Pearl River, New York, have implemented Total Quality Management (TQM) principles to evaluate and improve their effectiveness. Includes two charts that depict key indicators of financial and academic performance and a seven-year profile of the district's budget, enrollment, diploma rate,…

Cokeley, Sandra

1996-01-01

330

The Leica TCRA1105 Reflectorless Total Station  

SciTech Connect

This poster provides an overview of SLAC's TCRA1105 reflectorless total station for the Alignment Engineering Group. This instrument has shown itself to be very useful for planning new construction and providing quick measurements to difficult to reach or inaccessible surfaces.

Gaudreault, F.

2005-09-06

331

Total Quality Management: A Recipe for Success.  

National Technical Information Service (NTIS)

Total Quality Management (TQM) is a high level Department of Defense (DOD) initiative that is being touted as the primary management tool to force the fundamental cultural change in the way the DOD conducts business in the systems age. What is TQM. Where ...

M. G. Pazak

1990-01-01

332

Total Quality Management. ERIC Digest, Number 73.  

ERIC Educational Resources Information Center

|The Japanese success story has made W. Edwards Deming's Total Quality Management (TQM) theory increasingly popular among American managers, from car manufacturers to educational leaders. TQM is based on two tenets: the primacy of customer satisfaction and the necessity of tapping nontraditional sources (especially employee ideas) to institute…

Weaver, Tyler

333

Total Laparoscopic Hysterectomy for Large Uterus  

PubMed Central

Aim: In this review, we assessed the feasibility of total laparoscopic hysterectomy (TLH) in cases of very large uteri weighing more than 500 grams. We have analyzed whether it is possible for an experienced laparoscopic surgeon to perform efficient total laparoscopic hysterectomy for large myomatous uteri regardless of the size, number and location of the myomas. Design: Retrospective review (Canadian Task Force Classification II-1) Setting: Dedicated high volume Gynecological laparoscopy centre. Patients: 173 women with symptomatic myomas who underwent total laparoscopic hysterectomy at our center. There were no exclusion criteria based on the size number or location of myomas. Intervention: TLH and modifications of performing the surgery by ligating the uterine arteries prior, myomectomy followed by hysterectomy, direct morcellation after uterine artery ligation. Results: 72% of patients had previous normal vaginal delivery and 28% had previous cesarean section. Average clinical size of the uterus was 18 weeks (10, 32). The average weight of the specimen was 700 grams (500, 2240). The average duration of surgery was 107 min (40, 300) and the average blood loss was 228 ml (10, 3200). Conclusion: Total laparoscopic hysterectomy is a technically feasible procedure. It can be performed by experienced surgeons for large uteri regardless of the size, number or location of the myomas.

Sinha, Rakesh; Sundaram, Meenakshi; Lakhotia, Smita; Mahajan, Chaitali; Manaktala, Gayatri; Shah, Parul

2009-01-01

334

Total water management approach in steel industry  

Microsoft Academic Search

Water, due to its high specific heat capacity is considered to be an extremely attractive means for heat transfer (cooling) in industrial processes. A total water management plan for steel industry is presented here, taking into account local conditions, legal requirements and above all the availability of fresh water. The alternative water inlets which may also be used are presented

V. Tryfona-Panagopoulou; S. Panagopoulos; C. Panagopoulou; ?. ?ungolos

2011-01-01

335

Chapter 7 Total Internal Reflection Fluorescence Microscopy  

Microsoft Academic Search

Total internal reflection fluorescence microscopy (TIRFM), also known as evanescent wave microscopy, is used in a wide range of applications, particularly to view single molecules attached to planar surfaces and to study the position and dynamics of molecules and organelles in living culture cells near the contact regions with the glass coverslip. TIRFM selectively illuminates fluorophores only in a very

Daniel Axelrod

2008-01-01

336

The Total Neutron Cross Section of Nitrogen  

Microsoft Academic Search

The total cross section of nitrogen has been measured for neutrons in the energy range 200 to 1800 kev, using scatterers of liquid nitrogen and of lithium azide. Eleven resonances were found, corresponding to excited states in the compound nucleus N15, with natural widths of from 3 to 54 kev. Nine of these can be identified with resonances previously known

J. J. Hinchey; P. H. Stelson; W. M. Preston

1952-01-01

337

Iliopsoas bursitis following total hip replacement  

Microsoft Academic Search

We report the imaging features of a 52-year-old man presenting with a groin mass and gross lower limb oedema secondary to venous occlusion by massive cystic enlargement of the iliopsoas bursa 4 years after uncemented primary total hip replacement. Ultrasonography of the groin mass demonstrated a large cystic lesion extending into the pelvis. CT showed displacement of the external iliac vessels

Y. M. Cheung; C. M. Gupte; M. J. Beverly

2004-01-01

338

Mineral Analysis of Whole Grain Total Cereal  

ERIC Educational Resources Information Center

|The quantitative analysis of elemental iron in Whole Grain Total Cereal using visible spectroscopy is suitable for a general chemistry course for science or nonscience majors. The more extensive mineral analysis, specifically for the elements iron, calcium and zinc, is suitable for an instrumental or quantitative analysis chemistry course.|

Hooker, Paul

2005-01-01

339

Asymmetric total synthesis of ent-cyclooroidin  

PubMed Central

An enantiospecific total synthesis of the pyrrole-imidazole natural product cyclooroidin from histidine is described. The key N1-C9 bond is constructed through an intramolecular SN2-type of reaction of a chloro ester. Subsequent imidazole C2-azidation at the 2-position, pyrrole bromination, azide reduction and deprotection leads to the completion of the synthesis.

Mukherjee, Sabuj; Sivappa, Rasapalli; Yousufuddin, Muhammed; Lovely, Carl J.

2010-01-01

340

The Total Artificial Heart: Where We Stand  

Microsoft Academic Search

The AbioCor® total artificial heart (TAH) is undergoing clinical feasibility testing as destination therapy in patients with end-stage congestive heart failure. So far, the device has been implanted in 11 of a projected 15 patients. The TAH has performed reliably, providing adequate circulatory support while extending survival and improving quality of life in most recipients. Thromboembolism remains a problem but

O. H. Frazier; Robert D. Dowling; Nyma A. Shah; Toni Pool; Igor Gregoric

2004-01-01

341

Total Synthesis of (+)-Condylocarpine, (+)-Isocondylocarpine, and (+)Tubotaiwine  

PubMed Central

The first enantioselective total syntheses of indolealk aloids of the condylocarpine type are reported. (+)-Condylocarpine, (+)-isocondylocarpine, and (+)-tubotaiwine were prepared in high enantiomeric purity (er >99:1) from (1 S,5 R)-hexahydro-1,5-methano-1 H-azocino[4,3 -b]indole-12-one 7b by way of five or six isolated intermediates.

Martin, Connor L.; Nakamura, Seiichi; Otte, Ralf; Overman, Larry E.

2010-01-01

342

A modular total synthesis of (±)-trigonoliimine C.  

PubMed

A convergent total synthesis of trigonoliimine C has been executed by employing three catalytic transformations in sequence. The key reactions that have been developed in this context include the [Au]-catalyzed addition of protected tryptamine to isatogens and the reduction of N-OH to NH with hydrazine monohydrate. PMID:24036632

Narendraprasad Reddy, B; Ramana, Chepuri V

2013-09-26

343

Total dissociation cross section of halo nuclei.  

National Technical Information Service (NTIS)

Calculations of the total dissociation cross section is performed in the impact parameter representation. The case of (sup 11)Be and (sup 11)Li loosing one and two neutron(s), respectively, by collision on a (sup 12)C target, which remains in its ground s...

J. Formanek R. J. Lombard

1996-01-01

344

Solar Total Energy Systems. Technical progress report  

Microsoft Academic Search

A Solar Total Energy System (STES) is characterized by the use of solar energy for on-site generation of electricity, with recovery and reuse of turbine waste heat to meet thermal demands such as process heat, space heating and cooling, and water heating. The STES Mission Analysis being performed by The Aerospace Corporation has as objectives the identification and selection of

1977-01-01

345

Total quality management manifested through Ada  

Microsoft Academic Search

Depending on the source, Total Quality Management (TQM) is a philosophy, methodology, style, system, concept, or tool, or some combination thereof. As a solution to the dire predictions of America's dwindling leadership in the world marketplace, it can be said that TQM is the product of good old American ingenuity, inspired in the marketplace, in particular the high technology market,

John S. Medley

1991-01-01

346

Total synthesis of (+)-azinothricin and (+)-kettapeptin.  

PubMed

Asymmetric total syntheses of (+)-azinothricin and (+)-kettapeptin have been completed through a common new pathway that exploits a highly chemoselective coupling reaction between the fully elaborated cyclodepsipeptide 5 and the glycal activated esters 3 and 4 at the final stages of both respective syntheses. PMID:19175351

Hale, Karl J; Manaviazar, Soraya; George, Jonathan H; Walters, Marcus A; Dalby, Stephen M

2009-02-01

347

Total Synthesis of (?)-7-epi-Nemorosone  

PubMed Central

A concise total synthesis of (±)-7-epi-nemorosone is reported. Our synthetic approach establishes a viable route to polycyclic polyprenylated acylphloroglucinol natural products (PPAP’s) bearing a C-7 endo prenyl sidechain. Key steps include retro-aldol-vinyl cerium addition to a hydroxy adamantane core scaffold and palladium-mediated deoxygenation.

Zhang, Qiang; Porco, John A.

2012-01-01

348

Optimal pain management in total abdominal hysterectomy.  

PubMed

Effective postoperative pain management provides improved patient comfort and satisfaction, earlier mobilization, fewer pulmonary and cardiac complications, reduced risk of deep vein thrombosis, faster recovery, and reduced cost of care. Although many therapeutic modalities are available for pain management, the optimal combination in managing postoperative pain in total abdominal hysterectomy is controversial. The objective of this study was to review the literature to formulate optimal, evidence-based preoperative, intraoperative, and postoperative pain management for women undergoing total abdominal hysterectomy. Using the OVID platform, we searched in MEDLINE and PubMed using MeSH terms postoperative pain and total abdominal hysterectomy for published articles from 1960 to the present; we found 545 studies. We screened and included only randomized clinical trials, publications in English, human studies, and abdominal hysterectomy for noncancerous indications. We excluded 456 studies that reported on animal studies; laparoscopic, vaginal, supracervical, or robotic hysterectomy; pharmacokinetic studies; primary outcome other than pain management; and chronic pain management. Studies with inadequate power, poor methodology, or inconclusive results were further excluded from this review. Thus, 89 studies constituted the cohort for our article. Pain control remains complex given variables such as age, anxiety, and extent of surgery. In general, regimens should be tailored to the needs of the individual patient, taking into account medical, psychological, and physical condition. A multimodality approach is better than conventional, single-agent narcotic in achieving optimal pain management. After reading this article, the reader should be able to understand various modalities that can be considered for preoperative, intraoperative, and postoperative pain management in total abdominal hysterectomy. Target Audience: Obstetricians and gynecologists, family physicians Learning Objectives: After completing this CME activity, physicians should be better able to understand various modalities that can be considered for preoperative, intraoperative, and postoperative pain management in total abdominal hysterectomy. PMID:23945838

Azari, Laleh; Santoso, Joseph T; Osborne, Shelby E

2013-03-01

349

Total ozone variations at Reykjavik since 1957  

SciTech Connect

Total ozone measurements using a Dobson spectrophotometer have been performed on a regular basis at Reykjavik (65 deg 08 min N, 21 deg 54 min W), Iceland, since 1957. The data set for the entire period of observations has been critically examined. Due to problems related to the calibration of the instrument the data record of ozone observations is divided into two periods in the following analysis (1957-1977 and 1977-1990). A statistical model was developed to fit the data and estimate long-term changes in total ozone. The model includes seasonal variations, solar cycle influences, quasi-biennial oscillation (QBO) effects, and linear trends. Some variants of the model are applied to investigate to what extent the estimated trends depend on the form of the model. Trend analysis of the revised data reveals a statistically significant linear decrease of 0.11 +/- 0.07% per year in the annual total ozone amount during the earlier period and 0.30 +/- 0.11% during the latter. The annual total ozone decline since 1977 is caused by a 0.47 +/- 0.14% decrease per year during the summer with no significant change during the winter or fall. On an annual basis, ozone varies by 3.5 +/- 0.8% over a solar cycle and by 2.1 +/- 0.6% over a QBO for the whole observation period. The effect of the 11-year solar cycle is particularly strong in the data during the early months of the year and in the westerly phase of the QBO. The data also suggest a strong response of total ozone to major solar proton events.

Bjarnason, G.G.; Rognvaldsson, O.E.; Sigfusson, T.I.; Jakobsson, T.; Thorkelsson, B. [Univ. of Iceland, Reykjavik (Iceland)]|[Icelandic Meteorological Office, Reykjavik (Iceland)

1993-12-01

350

Mathematical evaluation of jumping distance in total hip arthroplasty  

PubMed Central

Background and purpose The jumping distance (JD) is the degree of lateral translation of the femoral head center required before dislocation occurs. The smaller the distance, the higher the theoretical risk of dislocation. The aim of our study was to evaluate this jumping distance and its variation according to the characteristics of the implant, and also the theoretical gain in using large head diameters of above 38 mm. Methods The JD was calculated as a function of the cup ante-version and abduction angles, the head diameter, and the head offset (defined as the distance between the center of the femoral head and the cup opening plane). Head diameters of 28, 32, 36, 40, 44 and 48 mm were analyzed. The abduction angle was increased from 0° to 80° with a 10° increment. The anteversion angle was increased from 0° to 40° with a 5° increment. Results The jumping distance was found to decrease as the cup abduction angle increased (0.25 mm each 1° for 32-mm head diameter). It increased by 0.05 mm for a 1° increase in the ante-version angle. The jumping distance increased as the head diameter increased (0.4 mm each mm diameter for a 45° abduction angle). The net gain obtained by increasing the diameter, however, decreased when abduction angle increased (0.25 each mm diameter for 60° abduction). The JD decreased by 0.92 mm for each 1-mm increase in head offset, showing that head offset was the most important parameter influencing the JD. Interpretation The theoretical gain in stability obtained by using a large femoral head (above 36 mm) is negligible in cases where there is a high cup abduction angle. An increase in offset of the femoral head substantially reduces the jumping distance and it should therefore be avoided.

Lazennec, Jean Yves; Khiami, Frederic; Catonne, Yves

2009-01-01

351

Relationship of plasma total protein and albumin to total calcium in peregrine falcons (Falco peregrinus)  

Microsoft Academic Search

A significant correlation was found between total calcium and total protein concentration in 124 plasma samples of captive peregrine falcons (r = 0.65; P<0.01). About 42% of the variability in calcium was attributable to the change in the plasma total protein concentration (R = 0.417). The correlation between calcium and albumin was significant (r = 0.33; P<0.01), but significantly smaller

J. T. Lumeij; J. D. Remple; K. E. Riddle

1993-01-01

352

Total and near-total gastrectomy for gastric cancer in patients over 70 years of age.  

PubMed

A total or near-total gastrectomy was performed in 52 patients over 70 years of age in our hospital from 1975 through 1982. The hospital mortality rate was 9.6 percent. The operation was palliative in nine patients. In these patients, the operation was performed because of an obstructing cancer. At last follow-up, 11 patients had survived more than 5 years and 6 patients were alive and free of disease more than 3 years after the operation. Total and near-total gastrectomies seem to be justified in elderly patients in good overall physical condition. PMID:2443029

Saario, I; Salo, J; Lempinen, M; Kivilaakso, E

1987-09-01

353

Surface cross-linked UHMWPE can enable the use of larger femoral heads in total joints.  

PubMed

Limiting cross-linking to the articular surfaces of ultrahigh molecular weight polyethylene (UHMWPE) to increase wear resistance while preventing detrimental effects of cross-linking on mechanical strength has been a desirable goal. A surface cross-linked UHMWPE can be achieved by blending UHMWPE with a free radical scavenger, such as vitamin E, consolidating the blend into an implant shape, extracting the vitamin E from the surface, and radiation cross-linking the surface extracted blend. This process results in high cross-link density in the vitamin E-depleted surface region because vitamin E hinders cross-linking during irradiation. In this study, we described the properties of successful extraction media and the manipulation of the wear and mechanical properties of extracted, irradiated blends. We showed that these formulations could have similar wear and significantly improved mechanical properties compared to currently available highly cross-linked UHMWPEs. We believe that these materials can enable thinner implant forms and more anatomical designs in joint arthroplasty and may provide a feasible alternative to metal-on-metal implants. PMID:22847503

Oral, Ebru; Neils, Andrew L; Lyons, Chelsea; Fung, Mitchell; Doshi, Brinda; Muratoglu, Orhun K

2012-07-30

354

Total aplasia of the paranasal sinuses.  

PubMed

Although a variety of theories have been proposed about functions of the paranasal sinuses, not one is clear today. Nonetheless, paranasal sinus-related diseases are associated with a high rate of morbidities. Therefore, it is essential to identify the structure and pathophysiology of the paranasal sinuses. Computed tomography (CT) is a valuable tool displaying anatomic variations and diseases. Because paranasal sinus development is a complex and long-lasting process, there are great structural variations between individuals. Several degrees and combinations of aplasias and hypoplasias have been reported; however, there is only one case of total paranasal sinus aplasia in the literature. Here, we present the second case of total paranasal sinus aplasia. Paranasal sinus development, functions of the paranasal sinuses, and the role of CT were evaluated. PMID:24124636

Korkmaz, Hakan; Korkmaz, Mukadder

2013-01-01

355

Total inorganic carbon in sea ice  

NASA Astrophysics Data System (ADS)

The method proposed for determining the total inorganic carbon (TC) concentrations in sea ice (Arctic region, North Pole-35 expedition) based on the measurement of the total alkalinity (TA) and the pH in the melt waters without the CO2 exchange with the atmosphere is considered. It is shown that the TC/Sal and TA/TC values through the entire ice section remain similar to these parameters in the subice water. The surface snow and the uppermost ice layers are characterized by elevated TA/TC values, which indicate the reaction Ca2+ + 2HCO{3/-} = ?CaCO3 + ?CO2 + H2O. The release of CO2 to the atmosphere due to the decomposition of calcium hydrocarbonate is as high as ˜20 mmol/m2. The meltwater of the examined ice is undersaturated with CO2, which may result in a sink of atmospheric CO2 (˜30 mmol/m2).

Nedashkovsky, A. P.; Shvetsova, M. G.

2010-12-01

356

Total body irradiation in chronic myeloid leukemia  

SciTech Connect

Total body irradiation (TBI), given as 10 rad daily for five days a week for a total dose of 150 rad has been used in an attempt to control the chronic phase of chronic myeloid leukemia (CML). Thirteen patients with CML received fractionated TBI leading to rapid and good control of WBC count without any adverse reaction. The chronic phase of CML could also be controlled with TBI, even in three patients who were resistant to busulfan. Following TBI, WBC count remained under control for a period of 32 weeks as compared to 40 weeks following vusulfan alone. Repeat TBI was also well tolerated with good response. It appears that TBI is an effective and safe therapy for controlling the chronic phase of CML.

Advani, S.H.; Dinshaw, K.A.; Nair, C.N.; Ramakrishnan, G.

1983-04-01

357

Nov. Total Solar Eclipse Observation from Antarctica  

NASA Astrophysics Data System (ADS)

PROGRAMME OF THE NOVEMBER 23/24 TOTAL SOLAR ECLIPSE OBSERVATION FROM ANTARCTICA A. Stoev1 P. Muglova2 1Yu. Gagarin Public Astronomical Observatory Stara Zagora Bulgaria 2Central Solar Terrestrial Influences Laboratory - Bulgarian Academy of Sciences Stara Zagora Department Bulgaria Observational tasks methods and instrumentation of the Total Solar Eclipse (TSE) South Pole’ 2003 program are presented in the paper. Photographic and video observations of the Sun during the different phases of the TSE are included in the programme. Basic aims of the programme are in the following directions: Investigation of the solar corona structure and microstructure dynamics and interrelation between different coronal elements and processes in time. Dust corona investigation. Experiments connected with atmospheric optic measurements actinometry and meteorology during the TSE.

Stoev, Alexey

358

Feminist leadership through total quality management.  

PubMed

Feminist leadership in nursing can be achieved through Total Quality Management. Total Quality Management (TQM) is a philosophy and technology that represents the foundation of a continuously improving organization. The feminist leadership ideas practiced by nurses, such as empowering staff and decision by consensus, are also central to TQM. Feminist leadership utilizing TQM enables employees to creatively contribute to the system without fear or intimidation. Employees at all levels in the organization are then empowered. The role of the feminist leader using TQM is one of facilitator rather than authority figure. Feminist leadership in nursing can spearhead the opportunity for improvement to provide high-quality, cost-effective health care in a troubled and complex economic environment. PMID:9119786

Lanza, M L

359

Total quality management: achieving service excellence.  

PubMed

Total Quality Management (TQM) provides a philosophy and a method for organizational renewal and redesign. It is based on the principle that productive work is accomplished through processes. Improving these processes requires the office team to objectively measure performance, discover root causes of problems, take corrective action, determine the effect of these actions, and secure achievements. TQM is a technique that provides a series of steps and set of tools. Through staff involvement and a desire for quality improvement, organizations involved in total quality note the accompanying satisfaction in taking constructive action, improving patient relations, and achieving service excellence. In today's competitive delivery environment, implementation of TQM can result in more satisfied patients, higher staff morale, and a more effective office team. PMID:9161134

Adelson, R

1997-01-01

360

Total aplasia of the paranasal sinuses  

PubMed Central

Although a variety of theories have been proposed about functions of the paranasal sinuses, not one is clear today. Nonetheless, paranasal sinus–related diseases are associated with a high rate of morbidities. Therefore, it is essential to identify the structure and pathophysiology of the paranasal sinuses. Computed tomography (CT) is a valuable tool displaying anatomic variations and diseases. Because paranasal sinus development is a complex and long-lasting process, there are great structural variations between individuals. Several degrees and combinations of aplasias and hypoplasias have been reported; however, there is only one case of total paranasal sinus aplasia in the literature. Here, we present the second case of total paranasal sinus aplasia. Paranasal sinus development, functions of the paranasal sinuses, and the role of CT were evaluated.

Korkmaz, Mukadder

2013-01-01

361

A Modern Approach to Total Wellbeing  

NASA Astrophysics Data System (ADS)

The events of the last decades have impacted our lives and our health significantly. We expected that the technology boom will improve our lives. While this may be true in a specific context, generally speaking our societies are suffering from moral decays, terrorism fears, wars, financial crisis and unpredictable acts of nature that are increasing in frequency and in intensity. The complex nature of the world we live is impacting our health and wellbeing considerably. Our health is not only determined by our physical health but is the end product of the interplay of the physical, mental, emotional, financial, relational and spiritual events of a lifetime. In this paper we develop a framework that will help us define and measure total wellbeing of individuals in our volatile societies. This framework will help us better understand the complex nature of total wellbeing and develop effective prevention and intervention strategies.

Hadzic, Maja; Chen, Meifania; Brouwer, Rick; Dillon, Tharam

362

Generalized principles of unchanging total concentration.  

PubMed

We consider the transport of multiple reacting species under the continuum assumption in situations such as those that frequently arise in electroanalytical chemistry. Under certain limitations, it has been shown that the total species concentration (as defined by Oldham and Feldberg) of such a system is uniform and constant. In this work, we extend the limits of the previous analysis to enable greater applicability. This is accomplished by using either of two new dependent variables, which are generalizations of the concept of total concentration. Then, conditions are determined under which the dependent variable will be uniform and constant in time. From a practical viewpoint, the described formalism allows one to simplify the multispecies transport problem formulation by eliminating one equation from the system of governing equations. PMID:16853140

Kottke, Peter A; Fedorov, Andrei G

2005-09-01

363

Total Synthesis of (+)-4,5-Deoxyneodolabelline  

Microsoft Academic Search

The first total synthesis of the marine dolabellane diterpene (+)-4,5-deoxyneodolabelline (1) has been accomplished. The highly efficient approach is characterized by the convergent assembly of dihydropyrans 2ab and cyclopentylsilanes 3ab. Allylic silane 3a was prepared from 2-methyl-2-cyclopen- tenone via a copper-catalyzed 1,4-addition followed by diastereoselective alkylation of the resulting enolate. A chemical resolution of racemic cyclopentanone 8 was effected by

David R. Williams; Richard W. Heidebrecht

2003-01-01

364

Total synthesis of insect antifeedant drimane sesquiterpenes  

Microsoft Academic Search

The investigations described in this thesis deal with the total synthesis of sesquiterpenes of the drimane family, named for their widespread occurrence in the stem bark of South American Drimys species. These compounds contain the bicyclofarnesol nucleus 1<\\/strong> , which is invariably oxidized at C-11 and\\/or C-12 and often at other sites as well (see figure 8.1).

B. J. M. Jansen

1993-01-01

365

Plasma total-homocysteine in anorexia nervosa  

Microsoft Academic Search

Objective: The measurement of plasma total-homocysteine (tHcy) as a marker of folate and cobalamin status in patients with anorexia nervosa.Design: Plasma tHcy, folate, cobalamin and other determinats of tHcy of a random group of patients with anorexia nervosa were compared with our own reference values.Setting: The study was performed at the tertiary children's Hospital Sant Joan de Déu.Subjects: All the

D Moyano; MA Vilaseca; R Artuch; C Valls; N Lambruschini

1998-01-01

366

Total synthesis of incarviditone and incarvilleatone.  

PubMed

The total synthesis of the racemic natural products (±)-incarviditone and (±)-incarvilleatone has been accomplished in three steps via biomimetic dimerization of (±)-rengyolone. Homochiral dimerization of (±)-rengyolone affords (±)-incarviditone through a domino oxa-Michael/Michael sequence. Heterochiral dimerization, involving a domino oxa-Michael/Michael/aldol reaction sequence, affords (±)-incarvilleatone. Single-crystal X-ray analysis of a derivative of (±)-incarviditone has resulted in revision of the originally proposed structure. PMID:22931401

Brown, Patrick D; Willis, Anthony C; Sherburn, Michael S; Lawrence, Andrew L

2012-08-29

367

Total synthesis of (-)-orthodiffenes A and C.  

PubMed

The efficient and concise synthesis of (-)-orthodiffenes A and C has been accomplished for the first time in eight steps from readily available chiral synthons, D-mannose and D-ethyl lactate. Our work confirmed the complete structure of orthodiffenes A and C, including their absolute stereochemistry. The key steps of our total synthesis involved cis-fused tetrahydrofuran cyclization, one-pot deprotection-lactonization, and intramolecular benzoyl migration according to a biosynthetic hypothesis of orthodiffenes. PMID:23051061

Liu, Jun; Liu, Yi; Zhang, Xing; Zhang, Chaoli; Gao, Yangguang; Wang, LinLin; Du, Yuguo

2012-10-22

368

Total synthesis of amphidinolide?f.  

PubMed

Orchestrated yet nonconsonant: The challenge posed by the "umpoled" 1,4-dioxygenation pattern characteristic for the polyketide frame of amphidinolide?F was mastered by a late-stage ring-closing alkyne metathesis followed by a directed transannular hydration under the aegis of a carbophilic ?-acid catalyst. This concordant strategy enabled a concise total synthesis of this enticing marine natural product. PMID:23610047

Valot, Gaëlle; Regens, Christopher S; O'Malley, Daniel P; Godineau, Edouard; Takikawa, Hiroshi; Fürstner, Alois

2013-04-22

369

Totally Chlorine Free Bleaching of Organosolv Pulps  

Microsoft Academic Search

Populustremula* tremuloides wood samples were processed in acetic acid–water–HCl media (Acetosolv pulping) and then subjected to totally chlorine free (TCF) bleaching sequences in order to obtain dissolving grade pulps. Several bleaching sequences (ZEQP1P2, EOQP1P2, EOPaaQP1P2, and EOZQP1P2) were assayed for this purpose. The best results corresponded to an EOZQP1P2 sequence, which led to pulps suitable for the manufacture of viscose

J. L. Alonso; J. C. Parajó; R. Yáñez

2003-01-01

370

Ventilation during total intravenous anaesthesia with ketamine  

Microsoft Academic Search

Total intravenous anaesthesia with ketamine (TIVAK) is widely used throughout the world especially in precarious conditions.\\u000a Although ketamine is usually considered to provide good respiratory function and may be used with spontaneous ventilation,\\u000a recent studies have shown that desaturations may occur. Seventy-six adults and 64 children scheduled for peripheral surgery\\u000a were randomly allocated to breathe spontaneously room air or 40%

Luc-Marie Joly; Dan Benhamou

1994-01-01

371

Two-level total lumbar disc replacement  

Microsoft Academic Search

Total lumbar disc replacement (TDR) has been widely used as a treatment option for 2-level symptomatic degenerative disc disease.\\u000a However, recent studies have presented conflicting results and some authors concluded that outcome deteriorated when disc\\u000a replacement was performed bisegmentally, with an increase of complications for bisegmental replacements in comparison with\\u000a monosegmental disc arthroplasty. The goal of the present retrospective study

Mario Di Silvestre; Georgios Bakaloudis; Francesco Lolli; Francesco Vommaro; Patrizio Parisini

2009-01-01

372

Measurement and prediction of total body fat.  

PubMed

Though it has been established that skinfold anthropometry has severe limitations as a method of deriving total body fat (TBF), the possibility that the problem might be related more to the assumptions implicit in densitometry has to be addressed. This paper suggests that smaller residual errors might be obtained if sums of skinfolds are regressed against TBF measured by a difference technique (IVNAA + 3H2O dilution), suggesting that the latter may perhaps be a better standard than densitometry. PMID:9569516

Beddoe, A H; Samat, S B

373

Regularized constrained total least squares image restoration  

Microsoft Academic Search

In this paper the problem of restoring an image distorted by a linear space-invariant(LSI) point-spread function (psf) which is not exactly known is formulated as the solution ofa perturbed set of linear equations. The regularized constrained total least-squares (RCTLS)method is used to solve this set of equations. Using the diagonalization properties of thediscrete Fourier transform (DFT) for circulant matrices, the

Vladimir Z. Mesarovic; Nikolas P. Galatsanos; Aggelos K. Katsaggelos

1995-01-01

374

The benefits of total quality management.  

PubMed

In this article, we will review the implementation of the ISO 9000 quality system in the Department of Nuclear Medicine. We will also discuss the benefits of working with the ISO 9000 standards and explain why we have shifted our focus from ISO 9000 towards the EFQM model. After an introduction concerning Total Quality Management and the EFQM model, we will describe how we have used the EFQM model to date and how we intend to implement TQM in the future. PMID:11137800

Geraedts, H P; Montenarie, R; van Rijk, P P

375

Total internal reflection with fluorescence correlation spectroscopy  

Microsoft Academic Search

Total internal reflection–fluorescence correlation spectroscopy (TIR-FCS) is an emerging technique that is used to measure events at or near an interface, including local fluorophore concentrations, local translational mobilities and the kinetic rate constants that describe the association and dissociation of fluorophores at the interface. TIR-FCS is also an extremely promising method for studying dynamics at or near the basal membranes

Bridgett L Steele; Nancy L Thompson

2007-01-01

376

Total Syntheses of (+)-Vigulariol and (-)-Sclerophytin A  

PubMed Central

The total synthesis of (+)-vigulariol and (?)-sclerophytin A are reported in 15 steps and 16 steps, respectively, from a known compound. The flexible, readily scalable synthetic strategy allows for rapid construction of a critical tricyclic intermediate and is demonstrated via the synthesis of these two marine natural products. A key reaction in this synthetic protocol is a combination Wittig/intramolecular Diels-Alder cycloaddition.

Stauffer, Christina S.; Mans, Mark C.

2011-01-01

377

Molecular Expressions: Total Internal Reflection Fluorescence Microscopy  

NSDL National Science Digital Library

This item is a comprehensive tutorial on TIRFM (total internal reflection fluorescence microscopy). The technology, developed in the 1980's, is used extensively in cell and molecular biology for observation of thin regions of a specimen, often less than 200nm. This tutorial includes fundamental concepts, theoretical aspects, basic and advanced microscope configurations, and a set of Java applets that depict the fluorophore excitation process and instrument configurations.

Davidson, Michael; Abramowitz, Mortimer; Axelrod, Daniel

2008-08-23

378

Total Maximum Daily Loads (303d) Glossary  

EPA Pesticide Factsheets

Water quality standards:  State or federal law or regulation consisting of a designated use or uses for the waters of the United States, water quality criteria for such waters based upon such uses, and an antidegradation policy and implementation procedures. Water quality standards protect the public health or welfare, enhance the quality of water and serve the purposes of the Clean Water Act.   From Total Maximum Daily Loads (303d) Glossary  -  Search all glossaries for terms containing (((health policy) in) US)

2012-05-09

379

Postmaterialism influencing total entrepreneurial activity across nations  

Microsoft Academic Search

The relative stability of differences in entrepreneurial activity across countries suggests that other than economic factors\\u000a are at play. The objective of this paper is to explore how postmaterialism may explain these differences. A distinction is\\u000a made between nascent entrepreneurship, new business formation and a combination of the two, referred to as total entrepreneurial\\u000a activity, as defined within the Global

Lorraine Uhlaner; Roy Thurik

2007-01-01

380

Formal total synthesis of palmerolide?A.  

PubMed

A formal total synthesis of the 20-membered marine macrolide, palmerolide?A from chiral pool tartaric acid is described. Elaboration of a ?-hydroxy amide, which is derived from the desymmetrization of tartaric acid amide, and Boord olefination are the pivotal reactions employed for the synthesis of the chiral building blocks, and Stille coupling and ring-closing metathesis (RCM) are used to assemble the macrolactone. PMID:23033158

Pawar, Amit B; Prasad, Kavirayani R

2012-10-02

381

Update on totally implantable venous access devices.  

PubMed

The use of totally implantable venous devices (TIVAD) has changed the care and quality of life for cancer patients, these devices allow chemotherapy administration, and blood sampling without the need for repeated venipuncture. These ports are used mainly when IV access is needed only intermittently over a long period of time. We are presenting a brief overview on TIVADs, with focus on the mid and long-term complications associated with these devices with their management. PMID:22425356

Zaghal, Ahmad; Khalife, Mohamed; Mukherji, Deborah; El Majzoub, Nadim; Shamseddine, Ali; Hoballah, Jamal; Marangoni, Gabriele; Faraj, Walid

2012-03-17

382

Neutron total cross section for tritium  

Microsoft Academic Search

The neutron total cross sections for hydrogen, deuterium, and tritium have been measured with the neutron-time-of-flight technique. The tritium data span the neutron energy range from 60 keV to 80 MeV, with an overall systematic uncertainty which varies from 0.5% for energies below 17 MeV to 2% at the highest energy measured; the statistical uncertainties exceed these values only below

T. W. Phillips; B. L. Berman; J. D. Seagrave

1980-01-01

383

First total synthesis of hunanamycin a.  

PubMed

The first total synthesis of hunanamycin A, an antibiotic natural product with a pyrido[1,2,3-de]quinoxaline-2,3-dione core from a marine-derived Bacillus hunanensis, is disclosed. The present effort provides access to sufficient amounts of scarce hunanamycin A for further biological evaluation and confirmation of the assigned absolute configuration. In addition, four new analogues of the natural product are reported. PMID:23964695

Shingare, Rahul D; Velayudham, R; Gawade, Jalindar R; Reddy, D Srinivasa

2013-08-21

384

Potential of tomotherapy for total scalp treatment  

Microsoft Academic Search

Purpose: Total scalp radiotherapy is required in a variety of clinical situations. We compared conventional lateral photon-electron (LPE) technique with tomotherapy (intensity-modulated radiotherapy [IMRT]).Methods and Materials: A patient with Merkel cell carcinoma was treated at our institution using conventional treatment techniques. Treatment plans were conducted using conventional three-dimensional treatment planning and IMRT. The clinical target volume included the entire scalp

Jay Locke; Daniel A Low; Todd Grigireit; K. S. Clifford Chao

2002-01-01

385

Results of near-total laryngectomy.  

PubMed

The clinical records of 225 patients undergoing primary or salvage near-total laryngectomy (NTL) for laryngeal and pyriform cancer were analyzed for local control and morbidity. If the primary cancer was laryngeal in origin, patients underwent a simple NTL; if it was pyriform, a minor modification called near-total laryngopharyngectomy (NTLP) was used. When NTLP was extended to include necessary portions of the tongue base or posterior pharyngeal wall, pharyngeal reconstructions were added. The principal outcomes studied were 1) 5-year local control of the primary cancer, 2) achievement of lung-powered shunt speech, and 3) incidence of aspiration. The local control of cancer was similar to that expected with total laryngectomy or laryngopharyngectomy. Conversational voice was achieved in 85% of patients surviving beyond 1 year. Some patients required additional surgery for voice -- usually endoscopic dilation. Aspiration was absent if primary healing was achieved. It was troublesome in wound breakdown if the shunt was directly affected. Secondary anti-aspiration procedures were required in 9% of our patients -- usually preserving shunt speech. PMID:9794609

Pearson, B W; DeSanto, L W; Olsen, K D; Salassa, J R

1998-10-01

386

Physical Activity After Total Joint Arthroplasty  

PubMed Central

Context: Total joint arthroplasty (TJA) is a common surgical option to treat painful degenerative joint disease. However, there is currently no consensus on the appropriate intensity of physical activity after TJA or how physical activity level affects the rate of revision surgery. Materials and Methods: A systematic review of the literature regarding physical or athletic activity after TJA was performed to determine current clinical opinion and recommendations regarding appropriate activity levels after TJA, as well as variables affecting successful surgery and improved outcomes. Results: Many studies in the literature regarding athletic activity after TJA focus on total hip arthroplasty and total knee arthroplasty. The literature reports contradictory results regarding rates of physical activity after TJA as well as the relationship between physical activity and rates of revision surgery. The current trend in expert opinion shows more liberal recommendations for patients to engage in athletic activity after TJA. Conclusions: Individual characteristics, lifestyle, and patient preferences must be taken into account when one considers appropriate recommendations for athletic activity after TJA. Current trends in clinical opinion favor a higher level of athletic activity after TJA, but clinicians should caution patients not to participate in contact sports or sports that create high joint loads in the replaced joint.

Vogel, Laura A.; Carotenuto, Giuseppe; Basti, John J.; Levine, William N.

2011-01-01

387

Femoral cement grading in total hip arthroplasty.  

PubMed

The current gold standard for primary total hip arthroplasty is a cemented femoral component combined with a porous-coated acetabular component. Barrack and colleagues described a femoral cement mantle grading system which is increasingly being used to evaluate surgical technique and to compare arthroplasty results. The immediate postoperative radiographs of 100 primary total hip arthroplasty cases from five community surgeons were assessed by three observers to evaluate the overall quality of cement technique, the interobserver variability in cement mantle grading, and specific characteristics of the grading system. All three observers agreed on the grading in only 73% of the x-rays (anteroposterior view, 69%; lateral view, 77%). Compared with reports in the literature from specialized hip arthroplasty centers, a very high proportion of the cases had grade C mantles. To gain a balanced perspective of the global effectiveness and longevity of cemented total hip arthroplasty it is important that follow-up studies be reported upon from representative cross sections of the orthopaedic community. PMID:9645519

Harvey, E J; Tanzer, M; Bobyn, J D

1998-06-01

388

Clinical pathway management of total knee arthroplasty.  

PubMed

Using a retrospective cohort study design, the authors examined complications, readmissions, morbidity and mortality, and function scores in two groups of patients attended by the same surgeon for the year before and the year after the implementation of an outcomes management program with clinical pathways for patients undergoing total knee arthroplasty at an academic health center. The effectiveness of the pathway constantly was adjusted using variance analysis and continuous quality improvement techniques. This program reduced the length of stay by 57% from a premanagement value of 10.9 +/- 5.4 days in 1994 (Group 1) to 4.7 +/- 1.4 days in 1996 (Group 2). Hospital costs (based on an inflation adjusted cost to charge ratio) for all total knees were reduced 11% from $13,328 +/- $3905 in 1994 to $11,862 +/- $4763 in 1996. Preoperative and postoperative knee scores were 41.1 +/- 16.3 and 84.2 +/- 16.0 for Group 1 and 42.5 +/- 13.0 and 87.0 +/- 10.4 for Group 2, respectively. There was no statistically significant difference between the preoperative or the postoperative knee scores of Groups 1 and 2. The application of clinical pathways, variance analysis, and continuous quality improvement toward the treatment of patients who had total knee arthroplasty at an academic health center resulted in significant savings in length of stay without adversely affecting overall outcome. PMID:9418629

Mabrey, J D; Toohey, J S; Armstrong, D A; Lavery, L; Wammack, L A

1997-12-01

389

Improved selection in totally monotone arrays  

SciTech Connect

This paper's main result is an O(({radical}{bar m}lgm)(n lg n) + mlg n)-time algorithm for computing the kth smallest entry in each row of an m {times} n totally monotone array. (A two-dimensional A = a(i,j) is totally monotone if for all i{sub 1} < i{sub 2} and j{sub 1} < j{sup 2}, < a(i{sub 1},j{sub 2}) implies a(i{sub 2},j{sub 1})). For large values of k (in particular, for k=(n/2)), this algorithm is significantly faster than the O(k(m+n))-time algorithm for the same problem due to Kravets and Park. An immediate consequence of this result is an O(n{sup 3/2} lg{sup 2}n)-time algorithm for computing the kth nearest neighbor of each vertex of a convex n-gon. In addition to the main result, we also give an O(n lg m)-time algorithm for computing an approximate median in each row of an m {times} n totally monotone array; this approximate median is an entry whose rank in its row lies between (n/4) and (3n/4) {minus} 1. 20 refs., 3 figs.

Mansour, Y. (Harvard Univ., Cambridge, MA (United States). Aiken Computation Lab.); Park, J.K. (Sandia National Labs., Albuquerque, NM (United States)); Schieber, B. (International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center); Sen, S. (AT and T Bell Labs., Murray Hill, NJ (United States))

1991-01-01

390

Total quality management -- Remedial actions planning program  

SciTech Connect

This paper describes the management approach being taken within the Hazardous Waste Remedial Actions Program (HAZWRAP) Support Contractor Office (SCO) to ensure quality of services in a highly competitive waste management environment. An overview is presented of the contractor support role assigned to Martin Marietta Energy Systems, Inc., by the Department of Energy (DOE) national program for managing hazardous waste. The HAZWRAP SCO mission, organizational structure, and major programs are outlined, with emphasis on waste management planning for the DOE Work for Others (WFO) Program. The HAZWRAP SCO provides waste management technical support, via interagency agreements between DOE and various Department of Defense (DOD) agencies for DOD sponsors planning remedial response actions. The remainder of the paper focuses on how the concept of Total Quality Management is applied to the HAZWRAP Remedial Actions Planning (RAP) Program. The management challenge is to achieve quality on a ''system'' basis where all functional elements of program management synergistically contribute to the total quality of the effort. The quality assurance (QA) program requirements applied to the RAP Program and its subcontractors are discussed. The application of management principles in the areas of program management, procurement, and QA to achieve total quality is presented. 3 refs.

Petty, J.L.; Horne, T.E.

1989-01-01

391

Total neutrino-scattering cross sections and total muon-capture rates in nuclei  

SciTech Connect

A simple relation between total inclusive neutrino-scattering cross sections and total muon-capture rates in nuclei is derived. The calculation makes use of the closure and the nonrelativistic impulse approximations. The relation is used to predict neutrino cross sections in /sup 12/C for E/sub ..nu../ = 150--250 MeV.

Kim, C.W.; Mintz, S.L.

1985-01-01

392

A Global Climatology of Total Ozone from the Nimbus 7 Total Ozone Mapping Spectrometer  

Microsoft Academic Search

A global climatology of total column ozone has been computed from 4 years of daily observations by the total ozone mapping spectrometer aboard the Nimbus 7 polar-orbiting satellite. Observations were made at local noon; no observations are available in polar regions during the polar night. The orbital data have been area averaged onto a regular 5 ø by 5 ø

Kenneth P. Bowman; Arlin J. Krueger

1985-01-01

393

Venous thromboembolic disease management patterns in total hip arthroplasty and total knee arthroplasty patients  

Microsoft Academic Search

The American Association of Hip and Knee Surgeons (AAHKS) distributed a survey to its members exploring practice patterns implemented to prevent venous thromboembolic disease (VTED) in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). Of 720 (33%) members, 236 responded. Prophylaxis was prescribed for 100% of patients during the course of hospitalization for THA and TKA. Warfarin

J. Wesley Mesko; Richard A Brand; Richard Iorio; Ivan Gradisar; Richard Heekin; Ross Leighton; Robert Thornberry

2001-01-01

394

Hadron-nucleon total cross section fluctuations from hadron-nucleus total cross sections  

Microsoft Academic Search

The extent to which information about fluctuations in hadron-nucleon total cross sections in the frozen approximation can be extracted from very high energy hadron-nucleus total cross section measurements for a range of heavy nuclei is discussed. The corrections to the predictions of Glauber theory due to these fluctuations are calculated for several models for the distribution functions, and differences of

David R. Harrington

1995-01-01

395

Total Synthesis of (?)- and (-)-Actinophyllic Acid  

PubMed Central

Development of efficient sequences for the total syntheses of (±)-actinophyllic acid (rac-1) and (?)-actinophyllic acid (1) are described. The central step in these syntheses is the aza-Cope/Mannich reaction, which constructs the previously unknown hexacyclic ring system of actinophyllic acid in one step from much simpler tetracyclic precursors. The tetracyclic hexahydro-1,5-methano-1H-azocino[4,3-b]indole ketone rac-37 is assembled from o-nitrophenylacetic acid in four steps, with oxidative cyclization of a dienolate derivative of tricyclic precursor rac-35 being the central step. In the first-generation synthesis, this intermediate is transformed in two steps to homoallyl amine rac-43, whose formaldiminium derivative undergoes efficient aza-Cope/Mannich reaction to give pentacyclic ketone rac-44. In four additional steps, this intermediate is advanced to (±)-actinophyllic acid. The synthesis is streamlined by elaborating ketone rac-37 to ?-hydroxyester intermediate rac-53, which is directly transformed to (±)-actinophyllic acid upon exposure to HCl and paraformaldehyde. This concise second-generation total synthesis of (±)-actinophyllic acid is realized in 22% overall yield from commercially available di-tert-butylmalonate and o-nitrophenylacetic acid by a sequence that proceeds by way of only six isolated intermediates. The first enantioselective total synthesis of (?)-actinophyllic acid (1) is accomplished by this direct sequence from tricyclic keto malonate (S)-35. Catalytic enantioselective reduction of ?,?-unsaturated ketone 66 is the key step in the preparation of intermediate (S)-35 from the commercially available Boc-amino acid 65. Discussed also is the possibility that the aza-Cope/Mannich reaction might be involved in the biosynthesis of (?)-actinophyllic acid.

Martin, Connor L.; Overman, Larry E.; Rohde, Jason M.

2010-01-01

396

Total-variation regularization with bound constraints  

SciTech Connect

We present a new algorithm for bound-constrained total-variation (TV) regularization that in comparison with its predecessors is simple, fast, and flexible. We use a splitting approach to decouple TV minimization from enforcing the constraints. Consequently, existing TV solvers can be employed with minimal alteration. This also makes the approach straightforward to generalize to any situation where TV can be applied. We consider deblurring of images with Gaussian or salt-and-pepper noise, as well as Abel inversion of radiographs with Poisson noise. We incorporate previous iterative reweighting algorithms to solve the TV portion.

Chartrand, Rick [Los Alamos National Laboratory; Wohlberg, Brendt [Los Alamos National Laboratory

2009-01-01

397

Formal total synthesis of spirangien A.  

PubMed

A formal total synthesis of the spiroketal containing cytotoxic myxobacteria metabolite spirangien A (1) is described. The approach utilizes a late introduction of the C20 alcohol that mirrors the biosynthesis of this compound. The key steps involved a high yielding cross metathesis reaction between enone 6 and alkene 7 to give E-enone 4 and a Mn-catalyzed conjugate reduction ?-oxidation reaction to introduce the C20 hydroxyl group. Acid treatment of the ?-hydroxyketone 4 gave spiroketal 19 which was converted into known spirangien A (1) advanced intermediate spiroketal 3. PMID:23320507

Gregg, Claire; Gunawan, Christian; Ng, Audrey Wai Yi; Wimala, Samantha; Wickremasinghe, Sonali; Rizzacasa, Mark A

2013-01-15

398

Gas extrusion in natural products total synthesis.  

PubMed

The thermodynamic driving force from the release of a gaseous molecule drives a broad range of synthetic transformations. This review focuses on gas expulsion in key reactions within natural products total syntheses, selected from the past two decades. The highlighted examples survey transformations that generate sulfur dioxide, carbon dioxide, carbonyl sulfide, or nitrogen through polar, radical, pericyclic, photochemical, or organometallic mechanisms. Of particular interest are applications wherein the gas extrusion enables formation of a synthetically challenging motif, such as an unusually hindered or strained bond. PMID:22940671

Jiang, Xuefeng; Shi, Lei; Liu, Hui; Khan, Akbar H; Chen, Jason S

2012-09-03

399

QCD sign problem as a total derivative  

NASA Astrophysics Data System (ADS)

We consider the distribution of the complex phase of the fermion determinant in QCD at nonzero chemical potential and examine the physical conditions under which the distribution takes a Gaussian form. We then calculate the baryon number as a function of the complex phase of the fermion determinant and show 1) that the exponential cancellations produced by the sign problem take the form of total derivatives, and 2) that the full baryon number is orthogonal to this noise. These insights allow us to define a self-consistency requirement for measurements of the baryon number in lattice simulations.

Greensite, Jeff; Myers, Joyce C.; Splittorff, K.

2013-08-01

400

Results with navigated bicontact total hip arthroplasty.  

PubMed

The position of the cup is crucial for the overall quality of a total hip arthroplasty. A malpositioning of the cup leads to increased risk of dislocation, wear, and revision. The position of the stem influences leg length and may cause impingement and dislocation. These faults may increase with minimally invasive procedures. From November 2001 to June 2005, 1081 consecutive THA patients were evaluated. Cup navigation resulted in a better alignment and additional improvement when the cup and stem were navigated. In stem navigation, a good control of the leg lengthening and a reliable prediction of the safe range of motion could be seen. PMID:16235445

Lazovic, Djordje; Kaib, Niels

2005-10-01

401

Total synthesis of 8-deshydroxyajudazol B.  

PubMed

The total synthesis of a stereoisomer of 8-deshydroxyajudazol B (4), the putative biosynthetic intermediate of the ajudazols A (1) and B (2), is described. The key steps in the synthesis included an intramolecular Diels-Alder (IMDA) reaction to secure the isochromanone fragment, a novel selective acylation/O,N-shift to give a hydroxyamide which was cyclized to the oxazole and a high yielding Sonogashira coupling to form the C18-C19 bond. Partial alkyne reduction then afforded the target 4. PMID:21410165

Birkett, Stephen; Ganame, Danny; Hawkins, Bill C; Meiries, Sébastien; Quach, Tim; Rizzacasa, Mark A

2011-03-16

402

Total synthesis and structural confirmation of (+)-longicin.  

PubMed

A stereocontrolled total synthesis of (+)-longicin, a representative of the class of mono-THF-acetogenins, is described. The strategy involves the utilization of d- and l-glutamic acids as chirons that correspond to two five-carbon segments harboring stereogenic centers at C4 and at C17 of the C(32) polyketide-derived natural product. The use of Grubbs' RCM reaction as a novel "chain elongation" strategy for the synthesis of acetogenin-type structures and a new protocol for butenolide incorporation are also described. [structure: see text] PMID:16119949

Hanessian, Stephen; Giroux, Simon; Buffat, Maxime

2005-09-01

403

Total volatile flux from Mount Etna  

Microsoft Academic Search

The Total Volatile (TV) flux from Mount Etna volcano has been characterised for the first time, by summing the simultaneously-evaluated fluxes of the three main volcanogenic volatiles: H2O, CO2 and SO2. SO2 flux was determined by routine DOAS traverse measurements, while H2O and CO2 were evaluated by scaling MultiGAS-sensed H2O\\/SO2 and CO2\\/SO2 plume ratios to the UV-sensed SO2 flux. The

A. Aiuppa; G. Giudice; S. Gurrieri; M. Liuzzo; M. Burton; T. Caltabiano; A. J. S. McGonigle; G. Salerno; H. Shinohara; M. Valenza

2008-01-01

404

Regulatory aspects of total product life cycle.  

PubMed

Total Product Life Cycle (TPLC) is a conceptual framework for assessing any product or service (medical or otherwise). This article will address how the Center for Devices and Radiological Health of the U.S. Food and Drug Administration utilizes TPLC in a regulatory paradigm. TPLC will help guide the regulation of market-driven evolution of medical devices and radiation-emitting products from conception, through pre-market development, to widespread market use, and finally to obsolescence and replacement by subsequent generations of products. PMID:15684626

Hausman, Ethan D; Altaie, Sousan S

2004-12-01

405

Total synthesis of the monoterpenoid alkaloid (±)-tangutorine.  

PubMed

A novel approach to a formal total synthesis of the monoterpenoid indole alkaloid (±)-tangutorine has been developed starting from an ?,?-unsaturated cyclic dehydroamino ester. Synthesis of the rather unusual trans-substituted 2,3-indoloquinolizidine substructure was accomplished via Cu(II)-mediated conjugate addition and organozinc/copper coupling as the key steps, thereby setting the stage for ring-closing metathesis to produce the quinolone substructure. Finally, Bischler-Napieralski cyclization gave rise to the pentacyclic system of (±)-tangutorine thereby realizing a formal synthesis in an overall yield of 5.2% in eight consecutive steps. PMID:22130791

van den Broek, Sebastiaan A M W; Lemmers, Jaap G H; van Delft, Floris L; Rutjes, Floris P J T

2011-12-01

406

Repeated events and total time on test  

PubMed Central

We adopt the Total Time on Test procedure to investigate monotone time trends in the intensity in a repeated event setting. The correct model is assumed to be a proportional hazards model, with a random effect to account for dependence within subjects. The method offers a simple routine for testing relevant hypotheses for recurrent event processes, without making distributional assumptions about the frailty. Such assumptions may severely affect conclusions concerning regression coefficients and cause bias in the estimated heterogeneity. The method is illustrated by re-analyzing Danish registry data and a long-term Swiss clinical study on recurrence in affective disorder.

Kvist, Kajsa; Andersen, Per Kragh; Angst, Jules; Kessing, Lars Vedel

2008-01-01

407

Reduction mammoplasty by the total dermoglandular pedicle.  

PubMed

The use of a total dermoglandular pedicle in 700 cases of reduction mammoplasty are described by this team of authors. They emphasize that their modification of the dermoglandular pedicle provides an extremely reliable blood supply to the areola and is quick and easy to perform. There is no anesthesia of the nipple postoperatively, and the shape of the breast is favorable both in the immediate postoperative period and over the long-term follow-up observation between the years 1979 and 1984. PMID:4072817

Moufarrege, R; Beauregard, G; Bosse, J P; Muller, G; Papillon, J; Perras, C

1985-01-01

408

Enantioselective total synthesis of macrolide (+)-neopeltolide.  

PubMed

The asymmetric total synthesis of the anti-proliferative macrolide (+)-neopeltolide has been completed. The stereochemically defined trisubstituted tetrahydropyran ring was constructed via a catalytic hetero-Diels-Alder reaction creating two new chiral centers in a highly diastereoselective manner. The other key features of this synthesis included Brown's asymmetric allylation to install the requisite C-11 and C-13 stereocenters. The synthesis of the oxazole side chain consisted of a hydrozirconation of an alkynyl stannane to establish the Z stereochemistry, followed by a palladium catalyzed cross coupling to introduce the desired Z olefin in the oxazole side chain. PMID:24121457

Ghosh, Arun K; Shurrush, Khriesto A; Dawson, Zachary L

2013-10-11

409

Paradoxical cerebral embolism after total knee arthroplasty.  

PubMed

Deep vein thrombosis is a frequent complication following total joint arthroplasty and other major orthopedic procedures. Pulmonary embolism occurs with or without a diagnosis of deep vein thrombosis, although infrequently (1.5%-10%). In patients with congenital cardiac defects, such as a patent foramen ovale, paradoxical cerebral embolism may also occur. This article describes a case of a 52-year-old woman who sustained a paradoxical cerebral embolism following total knee arthroplasty. In the workup of a patient with a known murmur and stroke symptoms, paradoxical cerebral embolism should be included in the differential. The initial evaluation should incorporate transesophageal echocardiography because of its accuracy in the demonstration of the cardiac physiology. An abnormal intracardiac or intrapulmonary shunt is essential for paradoxical cerebral embolism, allowing the entrance of the thrombus into cerebral circulation from the venous system. No clear consensus has been reached on the management of patients at risk for paradoxical cerebral embolism prior to orthopedic procedures. However, when an embolic stroke is diagnosed acutely, ideal management includes thrombolytic therapy, but further research is needed to confirm that this is the correct management. Due to the risk of recurrence, postoperative thromboprophylaxis is recommended with or without closure of the foramen ovale. Most importantly, and as demonstrated by the current patient, who partially recovered but did not require walking assistance after 2-year follow-up, treating physicians should be prepared to counsel patients through a lengthened physical rehabilitative process. PMID:23127461

Hill, Brian W; Huang, Hanwei; Li, Mengnai

2012-11-01

410

Near-total gastrectomy for gastric cancer.  

PubMed

Fifty-nine consecutive patients (95 percent) with gastric cancer of the distal portion of the stomach were operated on with 95 percent subtotal gastrectomy between 1975 and 1980. The operations were for cure in all cases. Twenty-five patients were alive after 5 years, for a crude 5 year survival rate of 42 percent. The operative mortality rate was 5 percent (three patients). Twenty-four patients (41 percent) had complications, which consisted of postoperative respiratory infection in 11 patients (19 percent), postoperative ileus in 4 patients (7 percent), and subphrenic abscess in 2 patients (3.4 percent). In addition, there was one wound dehiscence and one liver rupture (with fatal outcome), one deep venous thrombosis, one urinary infection, and one wound infection. Only one patient (1.7 percent) had an anastomotic leak at the gastrojejunostomy site. Seven relaparotomies (12 percent) had to be performed for complications. We have concluded that, in patients with distal gastric cancer, 95 percent subtotal gastrectomy can result in a 5 year survival rate that is comparable to that reported in the literature for total gastrectomy, and it has the advantage of a very low rate of anastomotic leakage between the minute gastric remnant and the jejunum. Therefore, 95 percent subtotal gastrectomy is recommended over total gastrectomy in the treatment of distal gastric cancer. PMID:3344915

Salo, J A; Saario, I; Kivilaakso, E O; Lempinen, M

1988-03-01

411

Enhanced recovery program in total hip arthroplasty  

PubMed Central

Background: Enhanced recovery program (ERP) was implemented to optimize the hospital stay in total hip arthroplasty. This study assessed the effects of optimizing preoperative and perioperative care using enhanced recovery (ER) on patients undergoing Total hip arthroplasty. Materials and Methods: We compared a prospective group of 64 patients on the ER program with a historic cohort of 63 patients that received conventional care (non ER). Results: ER patients were discharged earliest from hospital [mean length of stay (LOS) 5.3 days, median 4; P < 0.001] as compared to a mean of 8.3 days among non ER patients. Comparison based on American Association of Anesthesiologists (ASA) grades, preoperative hemoglobin, and body mass index (BMI) revealed that patients with ASA grade 3, preoperative hemoglobin of <14 g/dl, and BMI >30 on ER program spent shorter time in hospital as compared to the non ER's conventionally treated patients with more favorable physiological parameters of ASA grade 1 and 2, preoperative hemoglobin of >14 g/dl, and BMI <30. Conclusion: The ER protocol is universally beneficial and confers an advantage regardless of the patients’ preoperative condition.

Dwyer, Amitabh J; Tarassoli, Payam; Thomas, William; Porter, Paul

2012-01-01

412

Total Ore Processing Integration and Management  

SciTech Connect

This report outlines the technical progress achieved for project DE-FC26-03NT41785 (Total Ore Processing Integration and Management) during the period 01 October through 31 December of 2005. Graphical analysis of blast patterns according to drill monitor data is continuing. Multiple linear regression analysis of 16 mine and mill variables (powder factor, two modeled size fractions, liberation index, predicted grind, total crude Fe, Satmagan Fe, sat ratio, DSC, geologic blend, ambient temperature, cobbing hours, feeder plugs, and percent feeder run time-of-mill time) indicates that December variations in plant performance are generally predictable (Figure 1). The outlier on December 28th coincides with low cobbing availability and equipment downtime. Mill productivity appeared to be most influenced, as usual, by ore quality as indicated by the liberation index--the higher the liberation index, the lower the throughput. The upcoming quarter will be concerned with wrapping up the work in progress, such as the detailed statistical analyses, and writing a final report. Hibtac Mine engineers are evaluating neural network software to determine its utility for modeling, and eventually predicting, mill throughput.

Leslie Gertsch

2006-01-30

413

Totally thoracoscopic pulmonary anatomic segmentectomies: technical considerations  

PubMed Central

Background While video-assisted thoracic surgery (VATS) lobectomies are being increasingly accepted, VATS segmentectomies are still considered as technically challenging. With the renewed interest for sublobar resection in the management of early stage lung carcinomas, the thoracoscopic approach may have a major role in a near future. We report our technique and results. Patients and methods Totally thoracoscopic anatomic segmentectomiy, i.e., using only endoscopic instrumentation and video-display without utility incision, was attempted on 117 patients (51 males and 66 females), aged 18 to 81 years (mean: 62 years). The indication was a clinical N0 non-small cell lung carcinoma in 69 cases, a solitary metastasis in 17 cases and a benign lesion in 31 cases. The following segmentectomies were performed: right apicosuperior [26] right superior [10], right basilar [18], lingula sparing left upper lobectomy [15], left apicosuperior [11], lingula [7], left superior [14], left basilar [13] and subsegmental resection [3]. Segmentectomy was associated with a radical lymphadenectomy in 69 cases. Results There were 5 conversions to thoracotomy. The mean operative time was 181±52 minutes, the mean intraoperative blood loss was 77±81 cc. There were 12 postoperative complications (11.7%). The median postoperative stay was 5.5±2.2 days. Out of the 69 patients operated on for a cN0 lung carcinoma, 6 were finally upstaged. Conclusions Totally thoracoscopic anatomic pulmonary segmentectomies are feasible and have a low complication rate.

Zaimi, Rym; Fournel, Ludovic; Grigoroiu, Madalina; Brian, Emmanuel; Neveu, Charles

2013-01-01

414

Deep infection in total hip arthroplasty  

PubMed Central

Objective To report on a 30-year prospective study of deep infection in 1993 consecutive total hip arthroplasties performed by a single surgeon. Methods The relations of numerous variables to the incidence of deep infection were studied. Results The cumulative infection rate after the index total hip arthroplasties rose from 0.8% at 2 years to 1.4% at 20 years; 9.6% of the index operations required further surgery. When infections attributed to these secondary procedures were included, the infection rate rose from 0.9% at 2 years to 2% at 20 years. Although the usual variables increased the incidence of infection, the significant and most precise predictors of infection were radiologic diagnoses of upper pole grade III and protrusio acetabuli, an elevated erythrocyte sedimentation rate, alcoholism and units of blood transfused. Conclusion From 2–20 years, the incidence of deep infection doubled. Preoperative recognition of the first 4 risk factors permits the use of additional prophylactic measures. Spinal or epidural anesthesia reduced the units of blood transfused (the fifth risk factor) and, hence, the risk of infection. Although most deep infections are seeded while the wound is open, there are many possible postoperative causes. In this study, fewer than one-third of the infections that presented after 2 years were related to hematogenous spread. The efficacy of clean air technology was supported, and it is recommended that all measures that may reduce the incidence of deep infection be employed.

Hamilton, Henry; Jamieson, John

2008-01-01

415

Particle-enhanced total internal reflectance fluorescence  

NASA Astrophysics Data System (ADS)

This paper presents work toward a retrofit of an acaTMIV Discrete Clinical Analyzer (E. I. du Pont de Nemours and Company, Wilmington, DE) with a Particle Enhanced Total Internal Reflection Fluorescence technology. The DuPont acaTM line of instruments was designed to perform highly accurate unit dose clinical chemistry assays. Introduction of a Total Reflectance Fluorescence optics into an acaTMIV could provide capability to perform highly sensitive homogeneous immunoassays. Sensitivity and precision depended upon uniform immobilization of immunoglobulins or immunogens, representing examples of specific binding partners, onto an ionomeric material, acting as both solid support and wall material of the disposable reagent units called the `pack'. This study examines the uniformity of antibody coating onto various types of tough and flexible optical polymeric films including those made from the DuPont SurlynTM and NucrelTM polymers. A number of coating processes will also be described. Bioanalytical tools were developed to determine uniformity, quantity, and activity of antibody coated onto the `pack' film, thus allowing for optimization of polymer film type and process of antibody coating.

Chu, Victor P.; Zoha, Steven J.; Davis, Jim; Chance, Suzette

1995-04-01

416

Antibiotic prophylaxis in total hip replacement.  

PubMed Central

A controlled prospective trial to compare the efficacy of the antibiotics cephaloridine and flucloxacillin in preventing infection after total hip replacement was conducted at three hospitals. The antibiotic regimens began before surgery, cephaloridine being continued for 12 hours and flucloxacillin for 14 days afterwards. Over an 18-month period 297 patients undergoing a total of 310 hip replacements were entered into the trial and randomly allocated to one of the regimens. The follow-up period ranged from one to two and a half years. All operations were performed in conventional operating theatres; at two of the hospitals these were also used by various other surgical disciplines. Four patients developed deep infection, two having received the cephaloridine and two the flucloxacillin regimen. The overall rate of deep infection was therefore 1.3%. Thus three doses of cephaloridine proved to be as effective as a two-week regimen of flucloxacillin. Giving a prophylactic systemic antibiotic reduced the incidence of infection to a level comparable with that obtained in ultra-clean-air operating enclosures. Images FIG 1 FIG 2

Pollard, J P; Hughes, S P; Scott, J E; Evans, M J; Benson, M K

1979-01-01

417

On the total mass of closed universes  

NASA Astrophysics Data System (ADS)

The total mass, the Witten type gauge conditions and the spectral properties of the Sen-Witten and the 3-surface twistor operators in closed universes are investigated. It has been proven that a recently suggested expression {M} for the total mass density of closed universes is vanishing if and only if the spacetime is flat with toroidal spatial topology; it coincides with the first eigenvalue of the Sen-Witten operator; and it is vanishing if and only if Witten's gauge condition admits a non-trivial solution. Here we generalize slightly the result above on the zero-mass configurations: {M}=0 if and only if the spacetime is holonomically trivial with toroidal spatial topology. Also, we show that the multiplicity of the eigenvalues of the (square of the) Sen-Witten operator is even, and a potentially viable gauge condition is suggested. The monotonicity properties of {M} through the examples of closed Bianchi I and IX cosmological spacetimes are also discussed. A potential spectral characterization of these cosmological spacetimes, in terms of the spectrum of the Riemannian Dirac operator and the Sen-Witten and the 3-surface twistor operators, is also indicated.

Szabados, László B.

2013-08-01

418

Solar Total Energy Project final test report  

SciTech Connect

The Solar Total Energy Project (STEP), a cooperative effort between the United States Department of Energy (DOE) and Georgia Power Company (GPC) located at Shenandoah, Georgia, has undergone several design modifications based on experience from previous operations and test programs. The experiences encountered were discussed in detail in the Solar Total Energy Project Summary Report'' completed in 1987 for DOE. Most of the proposed changes discussed in this report were installed and tested in 1987 as part of two 15-day test programs (SNL Contract No. 06-3049). However, several of the suggested changes were not completed before 1988. These plant modifications include a new distributed control system for the balance of plant (BOP), a fiber a optical communications ring for the field control system, and new control configuration reflecting the new operational procedures caused by the plant modifications. These modifications were tested during a non-consecutive day test, and a 60-day field test conducted during the autumn of 1989. These test were partially funded by SNL under Contract No. 42-4859, dated June 22, 1989. Results of these tests and preliminary analysis are presented in this test summary report. 9 refs., 19 figs., 7 tabs.

Nelson, R.F.; Abney, L.O.; Towner, M.L. (Georgia Power Co., Shenandoah, GA (USA))

1990-09-01

419

Total energy concept - a special application  

SciTech Connect

As a means of making flower cultivation more economical, Dutch greenhouse operators are applying the total-energy concept by using gas-engine/generator sets to provide heat for the nursery and the soil as well as electricity for the artificial sunlight needed on overcast days. Although the gas-engine/generator set's efficiency is only 29% (compared with 34% for electricity from the grid), using heat exchangers to recover waste heat from the cooling water and the exhaust gases can raise the set's overall efficiency to more than 80%. The van den Bos nursery at Honselersdijk, Netherlands, has been operating a Caterpillar gas engine since 1977. Application of the total-energy principle has reduced energy costs (for gas plus electricity) by over $34,000/yr and primary energy (gas) consumption by 8.4 million CF/yr. Similar greenhouse installations have also chosen Caterpillar gas engines, which offer power ranges of 45-695 kW and compression ratios of 7-8:1 and 10-10.5:1, depending on the engine type and the gas quality.

de Jonge, H.F.

1980-12-01

420

On the total mass of closed universes  

NASA Astrophysics Data System (ADS)

The total mass, the Witten type gauge conditions and the spectral properties of the Sen-Witten and the 3-surface twistor operators in closed universes are investigated. It has been proven that a recently suggested expression for the total mass density of closed universes is vanishing if and only if the spacetime is flat with toroidal spatial topology; it coincides with the first eigenvalue of the Sen-Witten operator; and it is vanishing if and only if Witten's gauge condition admits a non-trivial solution. Here we generalize slightly the result above on the zero-mass configurations: if and only if the spacetime is holonomically trivial with toroidal spatial topology. Also, we show that the multiplicity of the eigenvalues of the (square of the) Sen-Witten operator is even, and a potentially viable gauge condition is suggested. The monotonicity properties of through the examples of closed Bianchi I and IX cosmological spacetimes are also discussed. A potential spectral characterization of these cosmological spacetimes, in terms of the spectrum of the Riemannian Dirac operator and the Sen-Witten and the 3-surface twistor operators, is also indicated.

Szabados, László B.

2013-11-01

421

MEASUREMENT AND DECOMPOSITION OF TOTAL EXPOSURE USING THE TOTAL-ISOLATED-BY-MICROENVIRONMENT-EXPOSURE (TIME) MONITOR  

EPA Science Inventory

This paper describes a new, highly compact and lightweight monitor that directly measures personal exposure resolved into four microenvironments. he device is the "Total-Isolated-by-Microenvironment-Exposure (TIME)" monitor. he monitor can identify electronically a subject's micr...

422

Synthesis of carbon nanotubes with totally hollow channels and/or with totally copper filled nanowires  

NASA Astrophysics Data System (ADS)

Carbon nanotubes (CNTs) with totally hollow channels and/or totally filled copper nanowires have been fabricated by methane decomposition using copper microgrid as a catalyst at 1173 K. The formation mechanism of CNTs with totally hollow channels is carbon precipitation at carbon-metal interface via the preferable surface diffusion mode of carbon. The selectivity of these CNTs can be improved by increasing the purity of copper catalysts and adding hydrogen in the feed gas. To form long and continuous copper nanowires up to 8 10 ?m the filling of copper in the CNT channel requires the liquid or quasi-liquid state capillary adsorption of nanosized copper at 1173 K under the thermal driving force. The filling volume ratio of copper to total nano-channel of the CNTs is firstly increased to about 50%. The copper inside the CNTs is of single crystalline form and face centered cubic (fcc) structure. The method is useful for further controlled synthesis of CNTs with totally hollow channels and/or totally copper filled nanowires.

Zhang, Q.; Qian, W. Z.; Yu, H.; Wei, F.; Wen, Q.

2007-02-01

423

Driver reaction times after total knee replacement.  

PubMed

We measured the driver reaction times of 40 patients before total knee replacement (TKR) and 4, 6, 8 and 10 weeks after operation. The ability to perform an emergency stop was assessed as the time taken to achieve a brake pressure of 100 N after a visual stimulus. There were 18 drivers and 11 non-drivers; the latter had longer reaction times. In drivers, the ability to transfer the right foot from accelerator to brake pedal did not recover to preoperative levels for eight weeks after right TKR and was unchanged after left TKR. Patients should be advised that they should not drive for at least eight weeks after right TKR. PMID:8083265

Spalding, T J; Kiss, J; Kyberd, P; Turner-Smith, A; Simpson, A H

1994-09-01

424

UPRE method for total variation parameter selection  

SciTech Connect

Total Variation (TV) Regularization is an important method for solving a wide variety of inverse problems in image processing. In order to optimize the reconstructed image, it is important to choose the optimal regularization parameter. The Unbiased Predictive Risk Estimator (UPRE) has been shown to give a very good estimate of this parameter for Tikhonov Regularization. In this paper we propose an approach to extend UPRE method to the TV problem. However, applying the extended UPRE is impractical in the case of inverse problems such as de blurring, due to the large scale of the associated linear problem. We also propose an approach to reducing the large scale problem to a small problem, significantly reducing computational requirements while providing a good approximation to the original problem.

Wohlberg, Brendt [Los Alamos National Laboratory; Lin, Youzuo [Los Alamos National Laboratory

2008-01-01

425

Total Quality Management and Cost of Quality  

NASA Astrophysics Data System (ADS)

Before we start analysing the philosophy of Total Quality Management it is worthwhile going back to the early days of quality and the quality movement. In fact, the quality concept dates back to the creation of Adam and Eve: “And God saw every thing that he had made, and, behold, it was very good”. (Genesis A 31). It is remarkable that at the end of each day, looking at his creations God was saying, “This is good”. However, at the end of the sixth day, after he finished the creation of human beings, he said, “This is very good”. It is amazing that he did not say, “This is excellent”. This is because excellence is something that we gain after tireless effort. God left room for improvement in order to challenge us and make our life more attractive, which has really happened!

Hadjicostas, Evsevios

426

Popliteal artery injury after total knee arthroplasty.  

PubMed

Total knee arthroplasty (TKA) is a commonly performed orthopedic procedure. The incidence of vascular complications after TKA is low. However, these complications may be debilitating, limb-threatening, and potentially avoidable. Our first patient, who had no preexisting vascular occlusive disease, developed an ischemic extremity after TKA. The second patient underwent TKA and was diagnosed with a severely ischemic limb 48 hours postoperatively. Both patients underwent above-knee to below-knee popliteal artery saphenous vein bypass grafting. Although limb salvage was obtained in both cases, one had a significantly neuropathic foot. In conclusion, long-term morbidity can be avoided by early identification and treatment of ischemia by bypass grafting. PMID:8615563

Mureebe, L; Gahtan, V; Kahn, M B; Kerstein, M D; Roberts, A B

1996-05-01

427

Sources of error in total knee arthroplasty.  

PubMed

The purpose of this study was to identify the procedural steps in a total knee arthroplasty (TKA) in which technical errors occur and to quantify the magnitude of these errors. Forty-nine consecutive TKAs were performed using a traditional exposure and manual instrumentation. An image-free computer navigation system (OrthoPilot; Aesculap AG, Tuttlingen, Germany) was used to measure and compare femoral and tibial alignment at specific procedural points during the TKA; this data was then used to evaluate possible sources of error in the procedure. The femoral cut tended to be made in hyperextension, the tibial cut tended to be made in hyperextension and valgus, and the tibial component tended to be implanted in valgus. This study identified specific points during the performance of a TKA where technical errors occur. This information suggests technical considerations that can help a surgeon achieve more reproducible, durable, and successful outcomes for his or her patients. PMID:19472971

Koyonos, Loukas; Stulberg, S David; Moen, Todd C; Bart, Gina; Granieri, Michael

2009-05-01

428

Aggregated Total Internal Reflection Optics for Solar  

NASA Astrophysics Data System (ADS)

An agglomeration of factors has stifled the economic promise of CPV. Foremost among these factors are: insufficient optical efficiency, misfit with existing solar infrastructure, high costs, and inadequate reliability of the optic-receiver package. These difficulties are significantly driven by the choice of optic. The CPV industry is constrained in a paradigm of bulky reflective or refractive optics that operate best at either low concentration (2-5x) or high concentration (100x and above). Low concentration approaches are plagued by marginal economics, while high concentration approaches face technical risks and do not fit well with the existing solar infrastructure. Using total internal reflection as the primary optical mechanism, a cost effective, line-focus optic can be produced at scale to provide superior optical performance in a flat profile and operate at a mid level of concentration to optimize the tradeoff between economic benefit and adoptability.

Schultz, David; Fine, Kevin; Evans, Matt; Ghosh, Shondip

2010-10-01

429

Totally Hip Software, Inc.: WebPainter  

NSDL National Science Digital Library

Web authors in search of a high-quality tool for creating GIF animations should consider WebPainter by Totally Hip Software. Animated GIFs are viewable with most browsers, and are an easy way to spice up a Web site. WebPainter includes excellent bitmap drawing and animation tools, including an "onion skin" feature that allows users to draw a new animation frame while seeing a lightened version of the previous frame underneath. Pricing information is available at the site. An evaluation version of both the Mac and Windows 95/NT versions of WebPainter, which allows users save the first five frames of animation, is available for download. WebPainter is an excellent product for Web authors who would like to create animated graphics.

1997-01-01

430

Total management of the open abdomen.  

PubMed

The management of complex abdominal problems with the 'open abdomen' (OA) technique has become a routine procedure in surgery. The number of cases treated with an OA has increased dramatically because of the popularisation of damage control for life-threatening conditions, recognition and treatment of intra-abdominal hypertension and abdominal compartment syndrome and new evidence regarding the management of severe intra-abdominal sepsis. Although OA has saved numerous lives and has addressed many problems related to the primary pathology, this technique is also associated with serious complications. New knowledge about the pathophysiology of the OA and the development of new technologies for temporary abdominal wall closure (e.g. ABThera™ Open Abdomen Negative Pressure Therapy; KCI USA Inc., San Antonio, TX) has helped improve the management and outcomes of these patients. This review will merge expert physician opinion with scientific evidence regarding the total management of the OA. PMID:22727136

Demetriades, Demetrios

2012-08-01

431

Recognizing the pitfalls of total quality management  

SciTech Connect

Should utilities be interested in total quality management (TQM) After all, the argument that better quality products should increase the sales and result in higher profits does not readily apply to a public utility operating in a monopolistic environment. Yet, utilities in the US are moving toward a more competitive environment; FPL's success with its TQM programs is forcing most utilities to look at TQM so as not to risk future competitive disadvantage. A few regulatory commissions have already started to inquire as to what steps utilities under their jurisdiction are taking to pursue the benefits of TQM. This article will address two facets of this issue. First, it will define what TQM is and identify the pitfalls that might keep a utility from attaining the full benefits of a well-executed TQM program. Second, it will lay out a simple, straightforward approach that a utility can use to determine whether and how to utilize this new management tool.

Laza, R.W.; Wheaton, P.L.

1990-04-12

432

Total quality management issues in managed care.  

PubMed

The implementation of total quality management (TQM) in health care has gone on in parallel with the growth of managed care. What is the interaction between the two? Key issues are the ascendance of cost control over quality in many areas, erosion of employee commitment and loyalty, and a short-run orientation. Associated with this is an emphasis on organizational learning rather than learning by autonomous professionals. Both TQM and managed care acknowledge the dynamic nature of clinical processes and the ability and responsibility of both institutions and clinicians to improve their processes. Both are consistent with efforts to identify and implement best practices. However, these similarities should not mask fundamental differences. Continuous improvement must shift its focus from avoiding unnecessary variation to facilitating rapid organizational learning and institutionalizing mass customization into the delivery of health services. PMID:9327355

McLaughlin, C P; Kaluzny, A D

1997-01-01

433

Total quality management in clinical virology laboratories.  

PubMed

The diagnostic laboratories in India are progressively promoting higher standards and are moving towards accreditation and international acceptance. Hence, the concept of "Quality" will need to be understood and implemented. Total quality management (TQM) in a laboratory is an integrated program involving all laboratory staff and management. TQM is a framework to operate and it is aiming for integration, consistency, increase in efficiency and a continuous drive for improvement. A well structured clinical virology service will include serology setup, cell culture facility and capacity for molecular diagnosis. The quality of results from the laboratory is significantly influenced by many pre-analytical and post-analytical factors which needed attention. The end goal of the TQM should be to provide the best care possible for the patient. PMID:17185843

Tibbets, M W; Gomez, R; Kannangai, R; Sridharan, G

2006-10-01

434

[Total Debranching through Mini-sternotomy].  

PubMed

Aneurysms of the aortic arch are technically challenging to repair with thoracic endovascular aneurysm repair (TEVAR). Various optional techniques such as debranching or hybrid TEVAR enable landing zones to extend, however, there is still room for improvement. We have performed total debranching to facilitate TEVAR with adequate central neck length more than 2.5 cm. In summary our procedure has 3 features:mini-thoracotomy to minimize its surgical stress which might cause post-operative respiratory failure, side-to-side anastomosis of trifurcated graft with ascending aorta to avoid its kinking after chest closure, and the usage of Pruitt-Inahara shunt tube during anastomoses of the carotid artery. PMID:24105115

Ujihira, Kosuke; Morishita, Kiyofumi; Shibata, Tsuyoshi; Saga, Toshifumi; Baba, Toshio; Mawatari, Toru

2013-10-01

435

Total Solar Eclipse Australia - Nov. 13, 2012  

NASA Video Gallery

On Nov. 13, 2012, a narrow corridor in the southern hemisphere experienced a total solar eclipse. The corridor lay mostly over the ocean but also cut across the northern tip of Australia where both professional and amateur astronomers gathered to watch. During a solar eclipse one can see – using appropriate instruments to protect the eyes since you should never look at the sun directly – dim structures around the edges of the sun. These structures are the sun's atmosphere, the corona, which extends beyond the more easily seen surface, known as the photosphere. In modern times, we know that the corona is constantly on the move. Made of electrified gas, called plasma, the solar material dances in response to huge magnetic fields on the sun. Structural changes in these magnetic fields can also give rise to giant explosions of radiation called solar flares, or expulsions of solar material called coronal mass ejections, CMEs – which make the corona a particularly interesting area to study.

Holly Zell

2012-11-14

436

Total parenteral nutrition in gynecology and obstetrics.  

PubMed

Although total parenteral nutrition (TPN) is accepted for the general surgical patient, it also has applications in management of certain gynecologic and obstetric patients. Over an 8.5-year period, 30 patients at a community hospital were referred for TPN from the obstetric and gynecologic service. The gynecologic patients were subdivided into 3 groups: those with rectovaginal fistulas, in whom colostomies were avoided; those with postoperative enterocutaneous fistulas and starvation; and those with postoperative prolonged ileus or mechanical intestinal obstruction and malnutrition, occasionally complicated by previous irradiation. Treatment with TPN obviated the need for surgery in many patients and improved the perioperative condition in others. In obstetrics, TPN was valuable in the treatment of severe hyperemesis gravidarum, inflammatory bowel disease, and the critically ill neonate. TPN can be an effective therapeutic tool in the management of a wide range of major nutritional problems facing the obstetrician-gynecologist. PMID:6768041

Hew, L R; Deitel, M

1980-04-01

437

Total endograft replacement of aortic arch  

PubMed Central

Total endovascular replacement of the aortic arch is a complex procedure that is often favoured when the pathology anatomy precludes a standard median sternotomy. Here we present the case of endograft repair in a 79 year old male with 6.5 cm arch aneurysm and 5.4 cm descending thoracoabdominal aneurysm. Following bilateral carotid-subclavian bypasses, a long 7 Fr sheath was advanced into the descending aorta through the common iliac artery purse string. A double curved long Lunderquist wire was guided to deep within the left ventricle, and the endograft carefully advanced over the wire. The graft was radiologically orientated, and deployed under asystolic conditions. Retrograde cannulation of the branches were accomplished, with carotid sheath placed into the branches followed by bridging stents. The graft delivery system was then removed. This approach obviates the need for a sternotomy, cumbersome extra-anatomic debranching, and hypothermic circulatory arrest.

Neequaye, Simon

2013-01-01

438

Total Ore Processing Integration and Management  

SciTech Connect

This report outlines the technical progress achieved for project DE-FC26-03NT41785 (Total Ore Processing Integration and Management) during the period 01 July through 30 September of 2005. This ninth quarterly report discusses the activities of the project team during the period 1 July through 30 September 2005. Richard Gertsch's unexpected death due to natural causes while in Minnesota to work on this project has temporarily slowed progress. Statistical analysis of the Minntac Mine data set for late 2004 is continuing. Preliminary results raised several questions that could be amenable to further study. Detailed geotechnical characterization is being applied to improve the predictability of mill and agglomerator performance at Hibtac Mine.

Leslie Gertsch; Richard Gertsch

2006-01-30

439

Hemodynamic regulation in total artificial heart recipients.  

PubMed

The right and left atrial pressures (RAP and LAP), circulating blood volume (CBV) and pump output were analyzed in 17 calves implanted with a free-diaphragm-type total artificial heart. A high RAP and increased CBV were common features in these animals, while the LAP was maintained in a nearly normal range throughout the course. Some correlation was seen between RAP, CBV and pump output, which was maintained in the range of 86.6 to 130.1 ml/min/kg. In the atrial myocardium various morphological changes were observed accompanied by thickening of the cell, which was conspicuous after one month of implantation. To improve this high venous pressure problem, an automatic controller for pusher-plate-type pumps wtih a greater sensitivity was introduced. A preliminary in vivo study using this new system is also reported. PMID:7247755

Harasaki, H; Takatani, S; Suwa, S; Jacobs, G; Snow, J; Kiraly, R; Nosé, Y

1981-02-01

440

Total Sleep Time Severely Drops during Adolescence  

PubMed Central

Restricted sleep duration among young adults and adolescents has been shown to increase the risk of morbidities such as obesity, diabetes or accidents. However there are few epidemiological studies on normal total sleep time (TST) in representative groups of teen-agers which allow to get normative data. Purpose To explore perceived total sleep time on schooldays (TSTS) and non schooldays (TSTN) and the prevalence of sleep initiating insomnia among a nationally representative sample of teenagers. Methods Data from 9,251 children aged 11 to 15 years-old, 50.7% of which were boys, as part of the cross-national study 2011 HBSC were analyzed. Self-completion questionnaires were administered in classrooms. An estimate of TSTS and TSTN (week-ends and vacations) was calculated based on specifically designed sleep habits report. Sleep deprivation was estimated by a TSTN – TSTS difference >2 hours. Sleep initiating nsomnia was assessed according to International classification of sleep disorders (ICSD 2). Children who reported sleeping 7 hours or less per night were considered as short sleepers. Results A serious drop of TST was observed between 11 yo and 15 yo, both during the schooldays (9 hours 26 minutes vs. 7 h 55 min.; p<0.001) and at a lesser extent during week-ends (10 h 17 min. vs. 9 h 44 min.; p<0.001). Sleep deprivation concerned 16.0% of chidren aged of 11 yo vs. 40.5% of those of 15 yo (p<0.001). Too short sleep was reported by 2.6% of the 11 yo vs. 24.6% of the 15 yo (p<0.001). Conclusion Despite the obvious need for sleep in adolescence, TST drastically decreases with age among children from 11 to 15 yo which creates significant sleep debt increasing with age.

Leger, Damien; Beck, Francois; Richard, Jean-Baptiste; Godeau, Emmanuelle

2012-01-01

441

Total Percutaneous Aortic Repair: Midterm Outcomes  

SciTech Connect

The purpose of this study was to examine the immediate and midterm outcomes of percutaneous endovascular repair of thoracic and abdominal aortic pathology. Between December 2003 and June 2005, 21 patients (mean age: 60.4 {+-} 17.1 years; 15 males, 6 females) underwent endovascular stent-graft insertion for thoracic (n = 13) or abdominal aortic (n = 8) pathology. Preprocedural computed tomographic angiography (CTA) was performed to assess the suitability of aorto-iliac and common femoral artery (CFA) anatomy, including the degree of CFA calcification, for total percutaneous aortic stent-graft repair. Percutaneous access was used for the introduction of 18- to 26-Fr delivery devices. A 'preclose' closure technique using two Perclose suture devices (Perclose A-T; Abbott Vascular) was used in all cases. Data were prospectively collected. Each CFA puncture site was assessed via clinical examination and CTA at 1, 6, and 12 months, followed by annual review thereafter. Minimum follow-up was 36 months. Outcome measures evaluated were rates of technical success, conversion to open surgical repair, complications, and late incidence of arterial stenosis at the site of Perclose suture deployment. A total of 58 Perclose devices were used to close 29 femoral arteriotomies. Outer diameters of stent-graft delivery devices used were 18 Fr (n = 5), 20 Fr (n = 3), 22 Fr (n = 4), 24 Fr (n = 15), and 26 Fr (n = 2). Percutaneous closure was successful in 96.6% (28/29) of arteriotomies. Conversion to surgical repair was required at one access site (3.4%). Mean follow-up was 50 {+-} 8 months. No late complications were observed. By CT criteria, no patient developed a >50% reduction in CFA caliber at the site of Perclose deployment during the study period. In conclusion, percutaneous aortic stent-graft insertion can be safely performed, with a low risk of both immediate and midterm access-related complications.

Bent, Clare L., E-mail: clare.bent@bartsandthelondon.nhs.uk; Fotiadis, Nikolas; Renfrew, Ian [Barts and The London NHS Trust, Department of Diagnostic Imaging (United Kingdom); Walsh, Michael; Brohi, Karim [Barts and The London NHS Trust, Department of Vascular Surgery and Trauma Surgery (United Kingdom); Kyriakides, Constantinos [Barts and The London NHS Trust, Department of Vascular Surgery and Queen Mary's School of Medicine and Dentistry (United Kingdom); Matson, Matthew, E-mail: Matthew.matson@bartsandthelondon.nhs.u [Barts and The London NHS Trust, Department of Diagnostic Imaging (United Kingdom)

2009-05-15

442

Development of a totally implantable artificial heart.  

PubMed

The first generation of an integrated, totally implantable electrohydraulic total artificial heart was designed for long-term cardiac replacement. The system consists of an elliptical blood pump with an interatrial shunt, Medtronic-Hall 27 mm and 25 mm inflow and outflow valves, respectively, an energy converter consisting of an axial-flow, hydraulic pump driven by a brushless DC motor, and an electronics system with transcutaneous energy transmission and telemetry. Energy is supplied by internal nickel-cadmium rechargeable batteries that supply power for 20 min and external silver-zinc batteries that are designed to supply energy to run the system for 5 hr. The blood pump consists of a single layer diaphragm cast from Biolon, with joined right and left ventricles sharing a common base. The dynamic stroke volume is 84 ml, and maximum cardiac output is 9.2 L/min at a heart rate of 110 beats/min on the mock circulation. A 4.3 mm diameter interatrial shunt is used to balance the volumetrically coupled ventricles. The energy converter pumps hydraulic fluid alternately between ventricles, with controlled, active filling in one ventricle during the systolic phase of the other ventricle. Internal or external controllers adjust the heart rate and motor speed to maintain normal atrial filling pressures and full stroke. Electromagnetic induction is used to transfer energy through the skin and a bidirectional infrared data link incorporated within the transcutaneous energy transmission coils is used to transmit information. The entire system is being assembled and refined for long-term animal implant studies. PMID:1457955

Rowles, J R; Khanwilkar, P S; Diegel, P D; Hansen, A C; Bearnson, G B; Smith, K D; Tatsumi, E; Olsen, D B

443

Favorable results after total wrist arthroplasty  

PubMed Central

Background and purpose During the past 40 years, several attempts have been made with total wrist arthroplasty to avoid fusion in severely destroyed wrists. The results have often been disappointing. There is only modest clinical documentation due to the small number of patients (especially non-rheumatoid cases) and short follow-up times. Here we report a multicenter series using a third-generation implant with a minimum follow-up time of 5 years. Methods In 2012, data were retrieved from a registry of consecutive wrist operations at 7 centers with units specialized in hand surgery, between 2003 and 2007. The wrists had been reviewed annually and analysis was done on the latest follow-up data. Results 60 patients had been operated (5 bilaterally), 5 wrists had been revised, and 52 were available for follow-up (with the revised cases excluded). The pain scores, QuickDASH scores, ulnar flexion, and supination for the whole group were statistically significantly better at follow-up. There were no statistically significant differences between the rheumatoid and the non-rheumatoid patients except for motion, which was better in the non-rheumatoid group. The motion obtained depended on the preoperative motion. Implant survival was 0.9 at 5–9 years. Interpretation The clinical results in terms of pain, motion, strength, and function were similar to those in previous reports. The implant survival was 0.9 at 9 years, both in rheumatoid and non-rheumatoid cases, which is an important improvement compared to the earlier generations of total wrist arthroplasty.

Boeckstyns, Michel E H; Herzberg, Guillaume; Merser, S?ren

2013-01-01

444

Malignant thyroid bed mass after total thyroidectomy  

PubMed Central

Purpose Ultrasonographic (US) criteria on malignant thyroid bed mass have been suggested, including taller than wide shape, loss of echogenic hilum, abnormal vascularity, and microcalcification. The relationship between fine-needle aspiration (FNA) cytology findings and US findings on thyroid bed mass is unknown. We have retrospectively assessed the malignant thyroid bed mass after total thyroidectomy due to papillary thyroid carcinoma (PTC). Methods We retrospectively evaluated 2,048 patients who underwent total thyroidectomy due to PTC. FNA was performed in 97 patients on the thyroid bed under US surveillance. The 97 suspicious thyroid bed masses were divided into two groups: metastatic thyroid bed group (n = 34) and nonmetastatic group (n = 63). The groups were evaluated according to various clinical, serologic, and US findings. Results Within a median 47.0 months of follow-up, the proportion of malignant thyroid bed mass was high in large tumor size (1.37 cm vs. 1.03 cm), isthmic position (10.3% vs. 3.9%), and previous N1a (55.9% vs. 34.9%). US findings revealed that the presence of microcalcification or macrocalcification (47.1% vs. 19.0%) and thyroid bed mass height (5.4 mm vs. 3.9 mm) were the only discriminable criteria for central compartment recurrence. But, degree of echogenicity, loss of hilum, and irregularity of margin failed to discriminate malignant thyroid bed mass. Conclusion US findings on malignant thyroid bed mass were different from previously reported general criteria on lateral metastatic nodes. Additional FNA cytology should be performed on patients, even low-risk patients, who present the above findings.

Park, Do Sung; Park, Min Ho; Ryu, Young Jae; Hwang, Min Jung; Shin, Sun Hyung; Kim, Hee Kyung; Lim, Hyo Soon; Lee, Ji Shin; Yoon, Jung Han

2013-01-01

445

Concerns with modularity in total hip arthroplasty.  

PubMed

Modularity is being diversified in total hip prostheses to increase surgical latitude in optimizing implant fixation and adjusting hip biomechanics. However, several problems have been clearly identified with implant modularity. First generation metal-backed acetabular components have shown deficiencies in the locking mechanism, the congruency and extent of polyethylene liner support, and polyethylene thickness, all of which have been implicated in accelerated polyethylene wear and failure. Evidence of screw motion against the metal backing, release of particulate material, and focal osteolysis have also been observed. At the head/neck junction evidence of corrosion and fretting has been documented with both similar-metal and mixed-metal taper combinations. Femoral prostheses with other sites of modularity present additional concerns with regard to mechanical integrity and generation of particulate debris by fretting. The modular junctions of three hip prostheses, the S-ROM, Infinity, and RMHS, were subjected to wet environment high cycle mechanical testing in a worst-case loading scenario. Preliminary results at relatively low loads up to three times body weight indicated gross stability of the modular junctions with evidence of minor fretting damage. Analysis of water solutions surrounding the modular junctions after ten to 20 million loading cycles yielded counts of one to three micron sized particles totalling several hundred thousand to several million. It is unknown what quantity of particulate material is sufficient to cause macrophage-mediated osteolysis or whether the debris from modular junctions can cause third-body wear of the articulating surfaces. Modular hip prostheses should be examined under stringent test conditions in order to characterize their fretting behavior and establish their mechanical limitations. PMID:8118986

Bobyn, J D; Tanzer, M; Krygier, J J; Dujovne, A R; Brooks, C E

1994-01-01

446

Image-guided total marrow and total lymphatic irradiation using helical tomotherapy  

SciTech Connect

Purpose: To develop a treatment technique to spare normal tissue and allow dose escalation in total body irradiation (TBI). We have developed intensity-modulated radiotherapy techniques for the total marrow irradiation (TMI), total lymphatic irradiation, or total bone marrow plus lymphatic irradiation using helical tomotherapy. Methods and Materials: For TBI, we typically use 12 Gy in 10 fractions delivered at an extended source-to-surface distance (SSD). Using helical tomotherapy, it is possible to deliver equally effective doses to the bone marrow and lymphatics while sparing normal organs to a significant degree. In the TMI patients, whole body skeletal bone, including the ribs and sternum, comprise the treatment target. In the total lymphatic irradiation, the target is expanded to include the spleen and major lymph node areas. Sanctuary sites for disease (brain and testes) are included when clinically indicated. Spared organs include the lungs, esophagus, parotid glands, eyes, oral cavity, liver, kidneys, stomach, small and large intestine, bladder, and ovaries. Results: With TBI, all normal organs received the TBI dose; with TMI, total lymphatic irradiation, and total bone marrow plus lymphatic irradiation, the visceral organs are spared. For the first 6 patients treated with TMI, the median dose to organs at risk averaged 51% lower than would be achieved with TBI. By putting greater weight on the avoidance of specific organs, greater sparing was possible. Conclusion: Sparing of normal tissues and dose escalation is possible using helical tomotherapy. Late effects such as radiation pneumonitis, veno-occlusive disease, cataracts, neurocognitive effects, and the development of second tumors should be diminished in severity and frequency according to the dose reduction realized for the organs at risk.

Schultheiss, Timothy E. [Department of Radiation Oncology, City of Hope Cancer Center, Duarte, CA (United States)]. E-mail: Schultheiss@coh.org; Wong, Jeffrey [Department of Radiation Oncology, City of Hope Cancer Center, Duarte, CA (United States); Liu, An [Department of Radiation Oncology, City of Hope Cancer Center, Duarte, CA (United States); Olivera, Gustavo [Tomotherapy, Inc., Madison, WI (United States); Somlo, George [Department of Medical Oncology, City of Hope Cancer Center, Duarte, CA (United States)

2007-03-15

447

38 CFR 3.343 - Continuance of total disability ratings.  

Code of Federal Regulations, 2013 CFR

...Continuance of total disability ratings. (a) General. Total disability ratings...improvement in physical or mental condition...the physical or mental demands of the course...incompatible with total disability. Neither...

2013-07-01

448

21 CFR 862.1175 - Cholesterol (total) test system.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Cholesterol (total) test system. 862.1175...Chemistry Test Systems § 862.1175 Cholesterol (total) test system. (a) Identification. A cholesterol (total) test system is a device...

2010-04-01

449

21 CFR 862.1175 - Cholesterol (total) test system.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Cholesterol (total) test system. 862.1175...Chemistry Test Systems § 862.1175 Cholesterol (total) test system. (a) Identification. A cholesterol (total) test system is a device...

2009-04-01

450

10 CFR 603.520 - Reasonableness of total project funding.  

Code of Federal Regulations, 2013 CFR

... false Reasonableness of total project funding. 603.520 Section 603.520 Energy... Pre-Award Business Evaluation Total Funding § 603.520 Reasonableness of total project funding. In cooperation with the...

2013-01-01

451

21 CFR 862.1470 - Lipid (total) test system.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Lipid (total) test system. 862.1470 Section...Clinical Chemistry Test Systems § 862.1470 Lipid (total) test system. (a) Identification. A lipid (total) test system is a device...

2009-04-01

452

21 CFR 862.1470 - Lipid (total) test system.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Lipid (total) test system. 862.1470 Section...Clinical Chemistry Test Systems § 862.1470 Lipid (total) test system. (a) Identification. A lipid (total) test system is a device...

2010-04-01

453

The Helmholtz Total Artificial Heart Labtype.  

PubMed

To perform the first experimental tests for validation of a new gear unit concept, the pump chamber, diaphragm, and pusher plate design of an orthotopic electromechanical total artificial heart (TAH) (Helmholtz Labtype) was manufactured. In its early stage of development, it provides some of the most important features of the conceptual final artificial heart. The new gear unit transforms a uniform unidirectional rotational motor movement into translatory pusher plate movements, with resting phase in the end-diastolic position, and the angled pump chamber orientation determines the available space for the motor and gear unit. Furthermore, this labtype provides flexibility with regard to use of different types of structural parts for experimental investigations. The first in vitro test results, obtained with specially designed circulatory mockloops that simulate physiological preload and afterload conditions, are presented. They comprise pressure and flow generation, motor performance, efficiency, and energy consumption. The results prove the feasibility of the new gear unit concept for an electromechanical artificial heart and allow a reliable determination of the necessary performance of the future brushless DC motor for the first in vivo TAH model. PMID:7980100

Kaufmann, R; Reul, H; Rau, G

1994-07-01

454

The (Almost) Unseen Total Eclipse of 1831  

NASA Astrophysics Data System (ADS)

The total eclipse of August 1831 began at sunrise in Australia, swept across the western South Pacific Ocean, and ended at sunset in the central South Pacific. As a result of the eclipse's path over mostly uninhabited ocean, the region's sparse European (British) population, and near-useless local predictions of the event at Hobart and Sydney in almanacs sold to the general public, almost no one witnessed its passage. In an attempt to document the eclipse, journals of naive observers - those having no access to a prediction - were examined. Thus far, the sole record is in the Pitcairn Island Register Book. Considering the Pitcairners' extreme isolation and the rather modest partial eclipse that occurred there, the entry is a surprising one; however, it can be explained in terms of events associated with their initial removal to Tahiti in March 1831 followed by their return home in June. Further, an authoritative means to identify any issues associated with eclipse predictions compiled for private-sector almanacs came in 1833 when sweeping changes in the British Nautical Almanac's section on eclipses were instituted.

Bartky, Ian R.

2008-03-01

455

Total parenteral nutrition in pancreatic disease.  

PubMed Central

Total parenteral nutrition (TPN) was given to 121 patients admitted with severe pancreatitis (73), chronic pancreatitis (23), or pancreatic malignancy (25) over 104 months. No adverse effects on the pancreas were detected from the TPN, including the provision of intravenous (IV) fat. Nutritional status was maintained or improved in all groups, including patients undergoing surgical procedures and those experiencing marked stress. No significant impact on the clinical course of pancreatitis was observed, although the death rate in acute pancreatitis (15.2%) and complicated pancreatitis (18.5%) compares favorably with other published series where early surgical intervention was undertaken. There was an increased risk of catheter-related sepsis in patients with complicated pancreatitis (14.8%) and with chronic pancreatitis (17.4%). No increase septic risk was seen in patients with acute pancreatitis or pancreatic malignancy. Eighty-two per cent of patients with acute pancreatitis required an average of 87 units of insulin per day while 78% of patients with chronic pancreatitis required an average of 54 units per day. In summary, TPN proved to be safe, effective, and well-tolerated in those patients with disorders of the pancreas.

Grant, J P; James, S; Grabowski, V; Trexler, K M

1984-01-01

456

Total auricular reconstruction without skin grafting.  

PubMed

Successful ear reconstruction depends on two factors: an ear framework and the skin covering the framework. However, the relative deficiency of skin for coverage of the cartilage framework remains an issue. This new method for total auricular reconstruction is a three-stage operation and involves the use of two tissue expanders. First, two skin expanders are implanted, one underneath the scalp and the other sited behind the microtic ear. At the second stage, after lobule transposition, the two expanded skin flaps (upper and lower) and mastoid fascial flap are raised. At the same time, the autogenous rib cartilage is harvested and the framework constructed. The cartilage framework is then anchored between the upper expanded skin flap and the fascial flap with its inferior pole inserted into the rotated earlobe. The upper expanded skin flap covers the whole anterior surface of the framework and drapes over the margins of the fascial flap, which wrap the framework from beneath. The raw surface of fascial flap is covered with the lower expanded skin flap. The formation of a pseudomeatus and tragus is performed at the third stage. Deficiency of skin is the major problem encountered with the other conventional methods. Our innovations using two tissue expanders in combination with an autogenous rib cartilage framework eliminate this problem completely. PMID:21703954

Liu, J; Sun, J; Li, X

2011-06-24

457

Acetabular blood flow during total hip arthroplasty  

PubMed Central

Objective To determine the immediate effect of reaming and insertion of the acetabular component with and without cement on periacetabular blood flow during primary total hip arthroplasty (THA). Design A clinical experimental study. Setting A tertiary referral and teaching hospital in Toronto. Patients Sixteen patients (9 men, 7 women) ranging in age from 30 to 78 years and suffering from arthritis. Intervention Elective primary THA with a cemented (8 patients) and noncemented (8 patients) acetabular component. All procedures were done by a single surgeon who used a posterior approach. Main outcome measure Acetabular bone blood-flow measurements made with a laser Doppler flowmeter before reaming, after reaming and after insertion of the acetabular prosthesis. Results Acetabular blood flow after prosthesis insertion was decreased by 52% in the noncemented group (p < 0.001) and 59% in the cemented group (p < 0.001) compared with baseline (prereaming) values. Conclusion The significance of these changes in periacetabular bone blood flow during THA may relate to the extent of bony ingrowth, periprosthetic remodelling and ultimately the incidence of implant failure because of aseptic loosening.

ElMaraghy, Amr W.; Schemitsch, Emil H.; Waddell, James P.

2000-01-01

458

Radiobiological speculations on therapeutic total body irradiation  

SciTech Connect

Unexpected total body irradiation (TBI) of human beings, involved in nuclear warfare or in accidents in nuclear reactors can be lethal. In the 1950s, bone marrow transplantation was discovered as a potentially life saving procedure after TBI in the dose range of 5.0 to 12.0 Gy. Since that time, deliberate or therapeutic TBI has been used to condition patients with a lethal bone marrow disorder for bone marrow replacement. The therapeutic ratio of TBI followed by bone marrow transplantation is small. Many potentially lethal complications can occur, such as acute TBI side effects, late TBI side effects or immunological complications of bone marrow transplantation such as graft versus host disease or graft rejection. The benefits of TBI and bone marrow transplantation are that they offer a chance for cure of previously lethal bone marrow disorders. The optimal parameters for TBI remain to be defined. The review discusses the current clinical and experimental animal data, as they relate to the future definition of less toxic TBI procedures with a better therapeutic ratio. Different TBI procedures are required for patients with malignant vs. non-malignant disorders or for patients with histoincompatible vs. histocompatible bone marrow donors.77 references.

Vriesendorp, H.M. (Johns Hopkins Hospital, Baltimore, MD (USA))

1990-01-01

459

Total syntheses of (+)-tedanolide and (+)-13-deoxytedanolide.  

PubMed

Convergent total syntheses of the potent cytotoxins (+)-tedanolide (1) and (+)-13-deoxytedanolide (2) are described. The carbon framework of these compounds was assembled via a stereoselective aldol reaction that unifies the C(1)-C(12) ketone fragment 5 with a C(13)-C(23) aldehyde fragment 6 (for 13-deoxytedanolide) or 52 (for tedanolide). Multiple obstacles were encountered en route to (+)-1 and (+)-2 that required very careful selection and orchestration of the stereochemistry and functionality of key intermediates. Chief among these issues was the remarkable stability and lack of reactivity of hemiketals 33b and 34 that prevented the tedanolide synthesis from being completed from aldol 4. Key to the successful completion of the tedanolide synthesis was the observation that the 13-deoxy hemiketal 36 could be oxidized to C(11,15)-diketone 38 en route to 13-deoxytedanolide. This led to the decision to pursue the tedanolide synthesis via C(15)-(S)-epimers, since this stereochemical change would destabilize the hemiketal that plagued the attempted synthesis of tedanolide via C(15)-(R) intermediates. However, use of C(15)-(S)-configured intermediates required that the side-chain epoxide be introduced very late in the synthesis, owing to the ease with which the C(15)-(S)-OH cyclized onto the epoxide of intermediate 50. PMID:18980317

Dunetz, Joshua R; Julian, Lisa D; Newcom, Jason S; Roush, William R

2008-12-01

460

[Total quality management in laboratory medicine].  

PubMed

The German Public Health will be continuously challenged in the future. It has to be assumed that modified managed care will not only take place sporadically. Thus, quality aspects of services gain more and more significance. Only suppliers will be successful who can offer services of highest quality at lowest prices. Quality in a comprehensive sense has to be substantiated in the near future. It is recommended to apply industry proven models also in public health service. Medical laboratories can be pioneers in this field as they have been already in the past. All previously proposed procedures can not describe quality of results comprehensively. They are based to a high degree on external control. Total quality management, however, represents a comprehensive approach. Principles are zero-defect approach, customer orientation and system management. Quality is given in the sense of TQM if the customer is permanently satisfied with the service of the supplier. In such a way, the customer defines quality of service. A customer is everyone who receives products or services. TQM overcomes the drawbacks of quality management systems, which are strongly formal and oriented by external control, as accreditation (EN 45,000) or certification (ISO 9000). Competition between hospitals is a declared goal of German health politics because usually quality is increased and cost decreased as a consequence. Competition means also comparison of services. TQM emphasizes benchmarking especially among the best suppliers. PMID:10028601

Vogt, W

1998-12-01

461

Total lightning activity in thunderstorms over Paris  

NASA Astrophysics Data System (ADS)

A statistical study of two groups of storms that occurred in the Paris area (France) during summer 2000 has been realized. The first group includes 26 high radar reflectivity (HRR) storms with radar reflectivity values exceeding 60 dBZ while the second one includes 19 moderate radar reflectivity (MRR) storms with a maximum radar reflectivity value between 50 and 55 dBZ. The radar reflectivity was provided by a C-band radar and the total lightning activity (cloud-to-ground (CG) and intra-cloud (IC) flashes) was provided by the French Météorage network and a Safir device. HRR storms seem to be characterized by a longer lifetime, and a more extended convective area. On average, they produce more CG and IC flashes than MRR storms. However, a large variability in the number, the rate, and the type of flashes is observed. The HRR storms producing the highest IC flash rates (above 100 min- 1) exhibit the lowest CG flash proportion (1.2 and 4.3%). Most of the HRR storms exhibit a peak lightning activity when the radar reflectivity is strong at low level within the cloud. However, several cases of these storms show a large time lag between the strong lightning production and the presence of high radar reflectivity values at low level. Some possible explanations of these observations, taking into account cloud dynamics, microphysics and lightning initiation, are discussed.

Boussaton, M. P.; Soula, S.; Coquillat, S.

2007-05-01

462

Human pancreatic cell autotransplantation following total pancreatectomy.  

PubMed Central

During total pancreaticoduodenectomy for chronic pancreatitis, four patients received an intraportal pancreatic mixed-cell autograft prepared by collagenase digestion. The technique of this autotransplantation procedure was successfully developed using a normal canine pancreas, but has proved difficult to apply in the human chronic pancreatitis model. Our four patients became insulin-dependent, with proof of intrahepatic insulin production in only one patient. Three factors have contributed to the lack of graft success: 1) the preoperative endocrine status, 2) systemic hypotension and portal hypertension secondary to graft infusion, and 3) difficulty applying the successful technique in a normal dog pancreas to an extensively scarred human pancreas. The preoperative insulin response during a glucose tolerance test was blunted or delayed in the three patients tested. An immediate decrease in blood pressure and rise in portal pressure occurred in every patient and prevented infusion of the entire graft (30-50%) in three patients. Unfortunately, the patient with the most compromised insulin status was the only patient able to receive the entire graft. Our experience would indicate that further refinements in technique are necessary to prevent the vascular reaction and allow infusion of the entire graft. Furthermore, normal islet cell function is necessary before a successful graft can be expected.

Traverso, L W; Abou-Zamzam, A M; Longmire, W P

1981-01-01

463

Wound necrosis after total knee arthroplasty.  

PubMed

Quickly evolutive skin necrosis and deep infection after total knee arthroplasty (TKA) are not uncommon. Several predisposing factors, such as immunosuppression, malnutrition, steroid use, rheumatoid arthritis, multiple scars, and vascular disease can be involved in the onset of wound complications, as well as long tourniquet time and early knee flexion. Skin necrosis after TKA can be treated in different ways, including local wound care, debridement, and soft tissue coverage with muscle or skin grafts. This article presents a rare case of skin necrosis occurring in a patient without any other apparent risk factor after TKA. A 78-year-old woman affected by primary osteoarthritis of the right knee who had no comorbidities and who had already undergone TKA for primary osteoarthritis on the left knee underwent a cemented TKA. Three days postoperatively, she developed a fever and wound problems, which soon after turned into skin necrosis. This complication was first treated surgically with a debridement of the wound with antibiotic therapy and local wound care, then with vacuum-assisted closure (Kinetic Concepts Inc, San Antonio, Texas) therapy and soft tissue coverage using skin grafting. She had a complete recovery in the next 3 months; the skin grafting was well tolerated and the range of motion and functional outcome were good. PMID:19292412

Patella, Vittorio; Speciale, Domenico; Patella, Silvio; Moretti, Biagio; Pesce, Vito; Spinarelli, Antonio

2008-08-01

464

APPARATUS FOR MEASURING TOTAL NEUTRON CROSS SECTIONS  

DOEpatents

An apparatus is described for measuring high-resolution total neutron cross sections at high counting rate in the range above 50-kev neutron energy. The pulsed-beam time-of-flight technique is used to identify the neutrons of interest which are produced in the target of an electrostatic accelerator. Energy modulation of the accelerator . makes it possible to make observations at 100 energy points simultaneously. 761O An apparatus is described for monitoring the proton resonance of a liquid which is particulariy useful in the continuous purity analysis of heavy water. A hollow shell with parallel sides defines a meander chamber positioned within a uniform magnetic fieid. The liquid passes through an inlet at the outer edge of the chamber and through a spiral channel to the central region of the chamber where an outlet tube extends into the chamber perpendicular to the magnetic field. The radiofrequency energy for the monitor is coupled to a coil positioned coaxially with the outlet tube at its entrance point within the chamber. The improvement lies in the compact mechanical arrangement of the monitor unit whereby the liquid under analysis is subjected to the same magnetic field in the storage and sensing areas, and the entire unit is shielded from external electrostatic influences.

Cranberg, L.

1959-10-13

465

[Rehabilitation and sport following total hip replacement].  

PubMed

The number of total hip replacement (THR) surgeries has increased significantly over the last few years and patients undergoing surgery are of decreasing age. In consequence the question of the influencing factors for the survival of artificial hip joints becomes more and more urgent. The expected survival time of an implant is nowadays 15-20 years and it seems that factors for a shorter lifetime are female gender, overweight, younger age and certain indications which led to surgery, such as rheumatoid arthritis or fractures. In the early phase of rehabilitation, measures against dislocation including training of the abductor muscles are most important. Starting rehabilitation programs early after surgery has positive effects on outcome, especially when strengthening programs are included. There are different opinions concerning the question how the lifetime of a THR is influenced by sports activities. However, it seems to have been demonstrated that suitable sports activities have a positive effect and do not necessarily correlate with higher loosening rates after THR. In general, high-impact sports should be avoided. Recommended activities are cycling, swimming, aquajogging, hiking, rowing and dancing. PMID:21607538

Schmitt-Sody, M; Pilger, V; Gerdesmeyer, L

2011-06-01

466

Total Artificial Heart and Physical Therapy Management  

PubMed Central

Purpose: To describe the total artificial heart (TAH) device as a bridge to heart transplantation (BTT), and related physical therapy management, while comparisons to left ventricular assist devices (LVAD) are made. Summary: The SynCardia CardioWest Temporary TAH System is the only TAH approved by the Food and Drug Administration (FDA), Health Canada and Consultants Europe (CE) for BTT. CardioWest implantation involves cardiectomy thus avoiding pulmonary hypertension, right heart failure, inotropic or anti-arrhythmic agents, myocardial and valve related problems. CardioWest has a fixed beat rate and cardiac output is dependent upon venous return and preload. Both TAH and LVADs are adaptive with exercise, increasing cardiac output during activities, allowing for conditioning to occur peripherally. Left ventricular assist devices have portable drivers permitting discharge home, while the CardioWest's large driver console necessitates inpatient therapy. Exercise progression, positioning, and monitoring of exercise intolerance are similar with LVAD and TAH. Ventricular fill volumes in TAH dictate cardiac output and require close attention. Cardiectomy in TAH prevents electrocardiography, telemetry, and native pulse rate monitoring. Conclusion: While mechanical differences exist between TAH and LVAD, physical therapists can provide evidence-based treatment for patients with TAH using previously established guidelines for patients with heart failure and mechanical circulatory support.

Nicholson, Clare

2010-01-01