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PubMed2000

Marked elevation of urinary zinc levels and pleural-friction rub in metal fume fever.

Zinc fume is a well-recognized cause of metal fume fever, characterized by acute or subacute symptoms of respiratory tract inflammation, myalgias and fever (similar to influenza) associated with a variety of metal oxide fumes. A welder of galvanized steel developed metal fume fever, a pleural friction rub and markedly elevated urinary zinc excretion despite work-site surveillance data indicating exposures close to the Occupational Safety and Health Administration, Permissible Exposure Limit. This patient suggests that exposure data may be misleading. This case had the highest urine zinc levels reported in the literature and a previously unreported coexistent pleural friction rub. The symptoms resolved with administrative and engineering controls to decrease exposure.

Adult↗
PubMed1975

Cleat-surface friction on new and old AstroTurf.

The authors have studied the alterations in cleat-surface friction of AstroTurf associated with use and exposure. Three cleat types were studied on five year old turf and on an unused, unexposed turf sample of the same production batch. Tests were carried out with and against surface grain under wet and dry conditions. It was found that with use and exposure the surface friction of AstroTurf does change, affecting both player performance and safety.

Athletic Injuries↗
PubMed2003

[Penis friction edema: not a venereal disease].

A 35-year-old man presented with a local swelling of the penis, which increased until the entire penis was thick and swollen. After infectious and obstructive causes had been eliminated, a diagnosis of 'penis friction oedema' was made. The swelling disappeared during several weeks of abstinence from sexual intercourse. Penile abnormalities can be divided into venereal diseases (STDs), incidental affections of the skin or mucous membranes in that location, and disorders of vascularisation and lymph drainage. A traumatic disorder of lymph drainage is sometimes referred to, unjustifiably, as 'penile venereal oedema'; it is a result of friction and manifests itself as local or total penile oedema or as a cordlike congestion of the lymphatic vessels. The diagnosis is by exclusion and the treatment is temporary abstinence from sexual intercourse.

Adult↗
PubMed2005

Productive friction: how difficult business partnerships can accelerate innovation.

Companies are becoming more dependent on business partners, but coordinating with outsiders takes its toll. Negotiating terms, monitoring performance, and, if needs are not being met, switching from one partner to another require time and money. Such transaction costs, Ronald Coase explained in his 1937 essay "The Nature of the Firm," drove many organizations to bring their activities in-house. But what if Coase placed too much emphasis on these costs? What if friction between companies can be productive? Indeed, as John Hagel and John Seely Brown point out, interactions between organizations can yield benefits beyond the goods or services contracted for. Companies get better at what they do--and improve faster than their competitors--by working with outsiders whose specialized capabilities complement their own. Different enterprises bring different perspectives and competencies. When these enterprises tackle a problem together, they dramatically increase the chances for innovative solutions. Of course, misunderstandings often arise when people with different backgrounds and skill sets try to collaborate. Opposing sides may focus on the distance that separates them rather than the common challenges they face. How can companies harness friction so that it builds capabilities? Start by articulating performance goals that everyone buys into. Then make sure people are using tangible prototypes to wrangle over. Finally, assemble teams with committed people who bring different perspectives to the table. As individual problems are being addressed, take care that the underpinnings of shared meaning and trust are also being woven between the companies. Neither can be dictated--but they can be cultivated. Without them, the performance fabric quickly unravels, and business partnerships disintegrate into rivalrous competition.

Commerce↗
PubMed2005

[Rolling friction: a desing of artificial knee joint].

Resorption and osteolysis of periimplant bones resulting from the wear debris of artificial joint will cause long-term loosening. A new type of rolling knee artificial joint without UHMWPE based on the mechanics of rolling friction is designed for alleviating this problem. Because of low friction force, the resistance of extension and flexion is reduced strikingly and the stress on the interface between prosthesis and bone is reduced evidently. In addition, the bio-toxicity caused by the wear debris of UHMWPE will not occur absolutely. In consequence, the rolling artificial joint can prevent the trend of long-term loosening of the prosthesis efficiently.

Animals↗
PubMed1986

Charnley low-friction arthroplasty. Review of the past, present status, and prospects for the future.

The evolution of Charnley low-friction arthroplasty highlights the scientific basis for the operation. Long-term results show that the quality of pain relief remains excellent. The quality of the socket fixation has been improved by the use of new methods and designs, while a new technique of stem fixation has all but eliminated the loosening. Ultimately, wear and creep of the high-density polyethylene socket must be given serious consideration. Low friction remains the sound concept, and trochanteric osteotomy, now incorporating an element of compression in its reattachment, remains the method of choice for the exposure.

Follow-Up Studies↗
PubMed1986

15-21-year results of the Charnley low-friction arthroplasty.

Ninety-three patients had had 116 Charnley low-friction arthroplasties (LFA) 15 to 21 years (mean, 16.6 years) previously. Their mean age at surgery was 53 years (range, 20-71 years). Fifty-two had osteoarthritis and 19 had rheumatoid arthritis. At follow-up, 85.3% were completely pain-free and 11.2% had occasional discomfort. Seventy-eight percent had near full or full range of movements. Acetabular bone-cement junction was unchanged in 32, and 20 had nonprogressive demarcation of the outer one third measuring less than 1 mm in width. In 36, socket demarcation was complete. Medial femoral cortex was unchanged in 56% and 44% showed loss of definition. Endosteal cavitation of the femur was present in 20.7%. Subsidence of the stem or the stem-cement complex was present in 29%. The diameter of the femoral cortex near the tip of the stem remained unaltered in 83.6%. The rate of socket wear was 0.096 mm/year, and there was a highly significant correlation between time and wear but no correlation between wear and patient's weight. Twenty-two and five-tenths percent of sockets migrated; this was statistically related to the depth of socket wear. The excellent clinical results of a relatively unsophisticated early surgical technique strongly supported the correct concept of the low-frictional torque. Improvements in the surgical technique and component design will further improve the long-term results.

Adult↗
PubMed1975

Friction blisters as a manifestation of pathomimia.

Self-inflicted skin lesions (pathomimia, artefacts) can be produced in a variety of ways, by the help of nails, razor blades, cigarettes, chemicals, etc. The present study reports three cases of pathomimia, in which the lesions consisted of vesicles or bullae producted by friction. Friction blisters can easily be produced in sites where the epidermis is both thick and firmly attached to the underlying tissues. The blisters have a characteristic histological appearance, which makes it possible to distinguish them from the blisters of different forms of vesicular and bullous diseases and from burn blisters which may also occur in pathomimia.

Adult↗
PubMed1984

[Friction melanosis].

We describe 23 cases of unusual brownish pigmentation occurring over the bony tissues such as clavicle, scapula or vertebrae. There were 19 females and 4 males. The age ranged from 18 to 59, mostly between 20 and 35 years. Since the first observation in 1977, cases gradually increased. The pigmentation usually showed ripple pattern on the upper back and clavicular region, zebra-like pattern over the ribs and postage-stamp-like macule over the vertebral column. Although there was no inflammatory sign such as itching or scaling, histology revealed postinflammatory melanin deposit in the upper dermis. Exceptional detection of amyloid deposit in the papillary layer in one case could be secondary to the slight epidermal damage actually disappeared. The general condition was not affected, and laboratory data remained within normal limits. This unique melanosis should be separated from other pigmentary disorders and macular amyloidosis. We would like to propose the name of friction melanosis, because this condition should be intimately related with the repeated friction by nylon towel or brush, widely used by young peoples in the bathroom.

Adolescent↗
PubMed1980

Hepatic friction rub in uremia.

Hepatic friction rubs developed in two patients undergoing maintenance hemodialysis. Thorough evaluation, including autopsy in one patient, did not demonstrate any known cause for the rubs except that uremic pericarditis had complicated the course of both patients and one suffered from chronic hemolytic anemia. The clinical course suggests that hepatic friction rubs may be associated with either uremia or maintenance hemodialysis.

Adult↗
PubMed2006

Hemocompatibility of low-friction boron-carbon-nitrogen containing coatings.

Mechanical heart valves are exposed to extreme mechanical demands, which require a surface showing not only nonhaemostatic properties, but also wear resistance and low friction. As alternative to different forms of amorphous carbon (a-C), so-called diamond-like carbon (DLC), the suitability of boron carbonitride (BCN) coatings is tested here for hemocompatible coatings. They have similar mechanical properties like a-C surfaces, but superior chemical stability at ferrous substrates or counterparts. BCN films with different nitrogen content were compared with hydrogenated a-C films regarding their mechanical properties, surface energy, adsorption of albumin and fibrinogen, blood platelet adherence, and activation of the contact system of the clotting cascade and kinin system. Similar mechanical properties and biological response have been found in the BCN films with respect to a-C, indicating the potential of these coatings for biomedical applications. The increase in the crystallinity and tribological properties of the BCN samples with a higher incorporation of N was also followed by a lower protein adsorption and low activation of the contact system, but an increased adherence of thrombocytes.

Blood↗
PubMed2005

Compact forceps manipulator using friction wheel mechanism and gimbals mechanism for laparoscopic surgery.

This paper reports evaluation of compact forceps manipulator designed for assisting laparoscopic surgery. The manipulator consists of two miniaturized parts; friction wheel mechanism which rotates and translates forceps (62 x 52 x 150[mm3], 0.6 [kg]), and gimbals mechanism which provides pivoting motion of forceps around incision hole on the abdomen (135 x 165 x 300 [mm3], 1.1 [kg]). The four-DOF motion of forceps around the incision hole on the abdomen in laparoscopic surgery is realized. By integration with robotized forceps or a needle insertion robot, it will work as a compact robotic arm in a master-slave system. It can also work under numerical control based on the computerized surgical planning. This table-mounted miniaturized manipulator contributes to the coexistence of clinical staffs and manipulators in the today's crowded operating room. As the results of mechanical performance evaluation with load of 4 [N], positioning accuracy was less than 1.2 [deg] in pivoting motion, less than 4 [deg] in rotation of forceps, less than 1.2 [mm] in longitudinal translation of forceps. As future works, we will modify mechanism for sterilization and safety improvement, and also integrate this manipulator with robotized forceps to build a surgery assisting robotic system.

Equipment Design↗
PubMed2005

Iliotibial band friction syndrome after anterior cruciate ligament reconstruction using the transfix device: report of two cases and review of the literature.

The use of hamstrings is increasing as a treatment for anterior cruciate ligament (ACL) injuries. There are a lot of new devices and techniques that try to fix the graft without causing further injury or increased morbidity. We report two cases in relation to the transfix device for reconstructing the ACL. The first case is a 38-year-old female who was treated with an autologous hamstring graft for chronic ACL instability brought on by a sport trauma. The patient developed iliotibial band friction syndrome 3 months after the operation. MRI showed incorrect positioning and a rupture of the femoral bio-absorbable cross-pin. The hamstring graft always had good fixation and did not produce instability of the knee. We removed the cross-pin fragment in a second surgery and the patient returned to her daily lifestyle after 3 weeks. The second case is a 52-year-old female with a painful and unstable knee due to a previous lateral meniscectomy and failure of an ACL reconstruction. We performed an ACL reconstruction with an autologous hamstring graft and a lateral meniscus transplantation. Some months after the procedure she also developed this syndrome. MRI showed the same features as shown in the first case and a second surgery was needed. To our knowledge this clinical and technical problem has not been previously described.

Adult↗
PubMed2003

Retrosternal friction-induced late disruption of the anastomotic site between Bentall's valved conduit and an aortic arch graft: report of a case.

We report a case of late mediastinal false aneurysm originating from disruption of the suture line between synthetic vascular grafts for aortic root and total aortic arch replacements. This aneurysm developed without any infection in a patient with Marfan's syndrome. To our knowledge, this event has never been reported before. The only possible cause of this disruption was that the monofilament suture was broken by continuous friction between the pointed anastomotic line and the sternum since the operation. The treatment options for this unusual event after extended synthetic graft replacement are discussed.

Adult↗
PubMed2004

The effect of shoe soling tread groove width on the coefficient of friction with different sole materials, floors, and contaminants.

Tread groove design is very common in footwear. However, coefficient of friction (COF) measurements between the footwear material and floor using a slipmeter were commonly performed using flat footwear pads. Such measurements might underestimate the actual slip resistance of the footwear pad. This research investigates the effects of the tread groove width on the measured COF using four footwear materials, three floors, and four liquid-contamination conditions using a Brungraber Mark II slipmeter. The analysis of variance results indicated that the footwear material, floor, contamination conditions, and groove width were all significant (p < 0.0001) factors affecting the measured COF. The hypothesis that wider tread grooves result in higher COF values was true with some exceptions especially on oil contaminated floors. A regression model, with an R2 of 0.91, was established to describe and predict the relationship between the COF and the tread groove width under footwear material/floor/contamination conditions.

Analysis of Variance↗
PubMed2007

Effects of slip testing parameters on measured coefficient of friction.

Slips and falls are a major cause of injuries in the workplace. Devices that measure coefficient of friction (COF) of the shoe-floor-contaminant interface are used to evaluate slip resistance in various environments. Testing conditions (e.g. loading rate, timing, normal force, speed, shoe angle) are believed to affect COF measurements; however, the nature of that relationship is not well understood. This study examines the effects of normal force (NF), speed, and shoe angle on COF within physiologically relevant ranges. A polyvinyl chloride shoe was tested using a modified industrial robot that could attain high vertical loads and relatively high speeds. Ground reaction forces were measured with a loadcell to compute COF. Experiment #1 measured COF over a range of NF ( approximately 100-500 N) for two shoe angles (10 degrees and 20 degrees ), four speeds (0.05, 0.20, 0.35, and 0.50 m/s), and two contaminants (diluted detergent and diluted glycerol). Experiment #2 further explored speed effect by testing seven speeds (0.01, 0.05, 0.20, 0.35, 0.50, 0.75, and 1.00 m/s) at a given NF (350 N) and shoe angle (20 degrees ) using the same two contaminants. Experiment #1 showed that faster speeds significantly decreased COF, and that a complex interaction existed between NF and shoe angle. Experiment #2 showed that increasing speed decreased COF asymptotically. The results imply that COF is dependent on film thickness separating the shoe and the heel, which is dependent on speed, shoe angle, and NF, consistent with tribological theory.

Accidental Falls↗
PubMed2005

Charnley low-frictional torque arthroplasty for avascular necrosis of the femoral head.

Forty-nine patients (mean age, 37 years; 20-50 years) had had 69 Charnley low-frictional arthroplasties for avascular necrosis of the femoral head. Their mean follow-up was 13.4 years (2-25 years). Five patients (8 hips) had no continuing follow-up, 5 (8 hips) are known to have died, 6 (7 hips) had had a revision at a mean follow-up of 16.4 years (11-25 years): 6 for cup loosening and 1 for a fractured stem and a loose cup. The remaining 33 patients (46 hips) had an excellent clinical result with all stems remaining soundly fixed, but 6 cups were radiologically loose at a mean follow-up of 16 years and 4 months. Wear and cup loosening are the main problems limiting the survival of the arthroplasty.

Adult↗
PubMed2001

The effect of roughness, floor polish, water, oil and ice on underfoot friction: current safety footwear solings are less slip resistant than microcellular polyurethane.

Research over a period of about 18 years has shown that a microcellular polyurethane known as AP66033 is the most slip-resistant safety footwear soling material on oily and wet surfaces. In recent years it has been replaced in commercially available footwear by a dual density polyurethane (DDP) which has a dense outer layer and a soft microcellular backing. This research programme has compared the slip resistance of AP66033 with DDP and some rubber solings. In addition, data were obtained on the effects of soling and floor roughness, and floor polish on slip resistance. Some data were also obtained for walking on ice. The coefficient of friction (CoF) of the solings was measured on 19 water wet surfaces in three conditions: (I) when the solings were new, (II) following abrasion to create maximum roughness and (III) after polishing. The CoF was measured on four oily surfaces after each of 11 abrasion or polishing treatments. The profound effects of the roughening of all soles and of floor roughness on the CoF were demonstrated for both wet and oily surfaces. The superior slip resistance of AP66033 was confirmed for oily and wet conditions; however, some rubbers not suitable for safety footwear achieved higher CoF values on wet floors. All of the floor polishes reduced the CoF of all floors when contaminated with water. The mean CoF of DDP solings was lower than the mean for AP66033 on wet and oily surfaces. No safety footwear soling provided adequate grip on dry ice and the CoF was reduced by water on the ice. A rubber used for rock climbing footwear was one of the most slip-resistant solings on wet surfaces in the laboratory but recorded the lowest CoF on ice. It is concluded that the incidence of occupational injuries caused by slipping could be reduced by the following: (A) returning to safety footwear soled with the microcellular polyurethane AP66033; (B) abrading all new and smooth footwear solings with a belt sanding machine coated with P100 grit; (C) avoiding the use of floor polish; (D) informing the general public about the poor slip resistance of ordinary footwear on ice and the lowering of slip resistance in cold weather.

Accidental Falls↗