Improving the heat transfer of nanofluids and nanolubricants with carbon nanotubes

Low thermal conductivity is a primary limitation in the development of energyefficient heat transfer fluids required in many industrial and commercial applications. To overcome this limitation, a new class of heat transfer fluids was developed by suspending nanoparticles and carbon nanotubes in these fluids. The resulting heat transfer nanofluids and nanolubricants possess significantly higher thermal conductivity compared to unfilled liquids. Three types of heat transfer nanofluids and nanolubricants, each containing controlled fractions of single-wall carbon nanotubes, multiwall carbon nanotubes, vapor grown carbon fibers, and amorphous carbon have been developed for multifunctional applications, based on their enhanced heat transfer and lubricity properties. For more information, contact F.D.S. Marquis, South Dakota School of Mines and Technology, Department of Materials and Metallurgical Engineering, Rapid City, SD 57701; (605) 394-1283; fax (605) 394-3369; e-mail fernand.marquis@sdsmt.edu.     

Diagnosis and treatment of aortic valve stenosis

The present review has attempted to summarize the classic symptoms and signs of aortic valve stenosis, especially in an adult. It is emphasized that all the classic signs rarely are present and their absence may mislead an unwary clinician. The diagnostic help provided by noninvasive tests, including echocardiography and phonocardiography, has been emphasized. A need for cardiac catheterization and angiography in most patients prior to corrective surgery is stressed. The natural history of the disease without operative intervention is dim and a significant risk of sudden death exists. The current surgical approach with immediate and long-term results is summarized. Finally, attention has been drawn to the special clinical circumstances when the aortic valve stenosis provides a strinkingly different clinical picture. We cannot find a better way to end this review than by quoting a warning note given by Thomas Lewis in 1920: "It is the faint cry of an anguished and fast failing muscle, which, when it comes, all should strain to hear, for it is not long repeated. A few months, a few years at most, and the end comes."     

What do children value in entertainment programs? A cross-cultural investigation

We investigated which program characteristics in children's entertainment television programs children between 6 and 11 years of age value. We collected data by means of questionnaires among 100 Dutch and 100 U.S. first through fourth graders. The most important characteristics for both Dutch and U.S. children were comprehensibility and action, closely followed by humor, interestingness, innocuousness, realism, violence, and romance, respectively. Compared to Dutch children, U.S. children attached more value to realism, innocuousness, and interestingness. Boys in both samples attached more value to action and violence in a children's program, whereas girls in both samples attached more value to innocuousness and comprehensibility.     

Perinatal observations on the etiology of congenital dislocation of the hip

At least 1 per cent of all newborn infants in the United Kingdom have CDH (Fig 10). Among these infants, approximately 85 per cent are normally formed and 15 per cent malformed. Among the normally formed infants, 90 per cent of the CDH are of the Grade 1 type, and 10 per cent of Grades 2 and 3. Such infants have a perinatal mortality of about 5 per cent. In contrast, among the malformed infants, about 50 per cent are CDH Grade 1, and 50 per cent Grades 2 and 3; their perinatal mortality is around 70 per cent. In other words, a much higher proportion than usual of the severe grades of CDH are found among the infants with a high perinatal mortality.     

Binding of radioactively labeled carboxyatractyloside, atractyloside and bongkrekic acid to the ADP translocator of potato mitochondria

1. The inhibition of the ADP-stimulated respiration of potato mitochondria by carboxyatractyloside is relieved by high concentration of ADP or by the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP). Atractyloside is a much less potent inhibitor than carboxyatractyloside. The inhibition of the ADP-stimulated respiration required about 60-times more atractyloside than carboxyatractyloside. 2. [35S]carboxyatractyloside and [3H]bongkrekic acid bind to potato mitochondria with high affinity (Kd = 10 to 20 nM, n=0.6-0.7 nmol per mg protein). Added ADP competes with carboxyatractyloside for binding; on the contrary ADP increases the amount of bound bongkrekic acid. [3H]atractyloside binds to potato mitochondria with a much lower affinity (Kd=0.45 muM) than carboxyatractyloside or bongkrekic acid. 3. Bound [3H]atractyloside is displaced by ADP, carboxyatractyloside and bongkrekic acid. The displacement of bound [35S]carboxyatractyloside by bongkrekic acid and of bound [3H]bongkrekic acid by carboxyatractyloside is markedly increased by ADP. 4. Bongkrekic acid competes with [35S]carboxyatractyloside for binding. Addition of a small concentration of ADP considerably enhances the inhibitory effect of bongkrekic acid on [35S]carboxyatractyloside binding. 5. The adenine nucleotide content of potato mitochondria is of the order of 1 nmol per mg protein. ADP transport in potato mitochondria is inhibited by atractyloside 30- to 40-times less efficiently than by carboxyatractyloside.     

Corneal neovascularization treated with argon laser

The argon laser set at 50 mum, 100-150 mW, o-2 s occluded corneal blood vessels in pigmented Dutch rabbits provided the corneal responsible for inducing vascularization was inactive. After arterial treatment with the argon laser retrograde flow in untreated veins was demonstrated by fluorescein angiography. Therefore all corneal new vessels should be treated, not just arteries. Minimal iris damage complicated the laser therapy, but this was not thought necessarily to contraindicate the use of the argon laser to treat corneal blood vessels in man. The iris damage was associated with outpouring of aqueous from the ciliary processes, and it took up to a week for the blood-aqueous barrier to return to its normal state.