Name:______________________________________ Section :______7.014 Problem Set 1Answers to this problem set are to be turned in at the box outside 68-120 by 11:45 am, Wednesday,February 9. Problem sets will not be accepted late. Solutions will be posted on the web.Please read the following two articles and use them to answer Question 1.Article IExcerpted from:Laptops can affect fertility in males, US researchers warn(full text at http://www.thedoctorslounge.net/fertilounge/articles/fertility_laptops)By Dr. Tamer Fouad, M.D. Saturday 1st January, 2005The increasing popularity of laptop computers (LC), coupled with existing evidence that increases intesticular or scrotal temperatures of between 1°C and 2.9°C are associated with a sustained andconsiderable negative effect on spermatogenesis and fertility, prompted researchers from the StateUniversity of New York at Stony Brook to undertake the first study into the effect of heat from LC onscrotal temperature. The findings are reported in journal Human Reproduction. They show that using anLC on the lap increased the left scrotal temperature by a median 2.6°C and the right by a median 2.8°C.Lead researcher Dr Yefim Sheynkin, Associate Professor of Urology and Director, MaleInfertility and Microsurgery at the University, said: "Laptops can reach internal operating temperatures ofover 70°C. They are frequently positioned close to the scrotum, and as well as being capable of producingdirect local heat, they require the user to sit with his thighs close together to balance the machine, whichtraps the scrotum between the thighs."The researchers worked with 29 healthy volunteers aged 21 to 35, measuring scrotal temperatureswith and without laptops. Two one-hour sessions of scrotal temperature measurements were performed ondifferent days in the same room with a median room temperature of 22.28°C. The men were dressed in thesame casual clothing for each session and sessions with and without LC were conducted at the same timeof the day. Body temperature was taken by mouth beforehand and each volunteer spent 15 minutesstanding in the room to adjust to room temperature before being seated. A non-working LC was placed onthe lap so that the volunteer could adopt the right position to balance the laptop, then removed, and theseating position held for one hour, with scrotal temperature being measured every three minutes. Thesame procedure was repeated for one hour, with the same baselines controls, but this time with a workinglaptop. The temperature of the bottom surface of the LC was also measured at intervals."We found that scrotal temperatures rose by 2.1°C when the men sat with their thighs together,which is necessary to keep LC on the lap. But, the rise was significantly higher when the LC were used –2.8°C on the right side and 2.6°C on the left," said Dr Sheynkin. "It shows that scrotal hyperthermia isproduced by both special body posture and local heating effect of LC." The median surface temperature ofPentium 4 computers used increased from nearly 31°C at the start of the experiment to nearly 40°C afterone hour.Dr Sheynkin said: "The body needs to maintain a proper testicular temperature for normal spermproduction and development (spermatogenesis). Portable computers in a laptop position produce scrotalhyperthermia by both the direct heating effect of the computer and the sitting position necessary tobalance the computer."Until further studies provide more information on this type of thermal exposure", he said,"teenage boys and young men may consider limiting their use of LC on their laps, as long-term use mayhave a detrimental effect on their reproductive health."Dr Sheynkin added that two LC brands were tested randomly to avoid criticism that brands maydiffer. "All laptop computers generate significant heat due to the increasing power requirements ofcomputer chips. New laptops with higher power requirements may produce even more heat. So far,computer fans and 'heat sinks' are not sufficient. It's possible that external protective devices couldsomewhat help, but it is essential to confirm their protective effect in a clinical study to preventcommercial advertising and use of inefficient and useless products."2Article IIExcerpted from:Hot Laptops A Male Reproductive Health Hazard - And Something You Can Do About It(full text with pictures at http://www.macopinion.com/columns/roadwarrior/05/01/04/ )by Charles Moore , Contributing Columnist 04 January 2005It has been well-established in past research that elevated scrotal temperatures caused by factors like too-tight jockey-style underwear or spending excessive amounts of time in hot tubs can damage sperm anddiminish fertility. Now it looks like using a laptop on your actual laptop can be added to the list.Recent findings published in the U.K. journal Human Reproduction by Dr. Yefim Sheynkin ofthe State University of New York at Stonybrook say that when men use laptop PCs on their laps, acombination of factors elevates temperatures around their genitals and over time can result in decreasedsperm production – jeopardizing fertility. The factors are: (1). Heat generated by the laptop (2). Unnaturalposture with knees squeezed together in order to balance the laptop on their lap.!The Sheynkin report inHuman Reproduction cautions that teenagers and young men especially should limit time spent with acomputer positioned on their lap because of the possible long-term damage to their fertility.Sheynkin’s researchers found that in 29 volunteers between the ages of 21 and 35 who took partin the study sitting with the thighs together to balance a laptop, scrotal elevated temperatures by 2.1°C(3° F). However when a laptop was in use, average temperatures rose by 2.6°C (4°F) on the left of thescrotum and 2.8°C (5°F) on the right (I deduce that the laptops used in the study had their processorlocated on the right). The average surface temperature of the computers used in the experiment increasedfrom nearly 31°C (87.8°F) at the start of the test to nearly 40°C (104°F) after one hour.But there will be a projected 60 million laptops in the U.S. and 150 million worldwide by 2005.Dr. Sheynkin is quoted by IDG News Service’s Laura Rohde commenting that: “It’s possible thatexternal protective devices could help.”One such device would be the $30 Laptop Desk from LapWorks Inc. Used as lap trays, theLaptop Desks address both the heat and the posture issues. They have
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