Thursday, December 23, 2010

Projects For You : Pyroelectric Fire Alarm

PYROELECTRIC FIRE ALARM 
By D. Mohan Kumar [Electronics For you]


Here is an ultra-sensitive fire sensor that exploits the direct piezoelectric property of an ordinary piezo element to detect fire. The lead zirconate titanate crystals in the piezo element have the property to deform and generate an electric gate protected p-channel MOSFETs in the inputs. It has high speed of performance and low input current requirements.

There are two inputs—the non-inverting input (pin 3) connected to the piezo element through diode D7 (OA71) that carries the voltage signal from the piezo element and the inverting input (pin 2) that gets a preset voltage momentarily changes the voltage level at pin 3 of IC1 and its output swings high. Transistor T1 conducts taking the reset pin 12 of IC2 to ground. IC2 is now enabled and starts oscillating. With the shown values of the oscillating components C3 (0.22μ) and R6 potential when heated, thus converting the piezo element into a heat sensor.

The circuit described here is very sensitive. It gives a warning alarm if the room temperature increases more\ than 10°C. The entire circuit has two sections—the sensor and the power supply section.

Sensor side circuit. Fig. 1 shows the fire sensor circuit. The front end of the circuit has a sensitive signal amplifier built around IC1 (CA3130). It gives a high output when temperature near the piezo element increases. IC CA3130 is a CMOS operational amplifier with voltage through VR1. By adjusting VR1, it is easy to set the reference voltage level at pin 2. 

In normal condition, IC1 gives a low output and the remaining circuitry is in a standby state. Capacitor C2 keeps the non-inverting input of IC1 stable, so that even a slight change in voltage level in the inputs can change the output to high.

Normally, IC1 gives a low output, keeping transistor T1 non-conducting. Reseting pin 12 of IC2 (CD4060) connected to the collector of transistor T1 gets a high voltage through R5 and IC2 remains disabled. When the piezo element gets heat from fire, asymmetry in its crystals causes a potential change, enabling capacitor C2 to discharge. 

It (1M), the first output (Q3) turns high after a few seconds and a red LED2 starts flashing. If heat near the piezo persists, Q7 (pin 14) output of IC2 becomes high after one minute, and the alarm starts beeping. If heat continues, Q9 (pin 15) turns high after four minutes and turns on the relay driver transistor T2. At the same time, diode D8 conducts and IC2 stops oscillating and toggles.

The solenoid pump connected to the N/O (normally opened) contact of the relay starts spraying the fire-ceasing foam or water to the possible sites of fire. 

Power supply circuit. Power supply section (Fig. 2) comprises a 0-12V, 1A step-down transformer with a standard full-wave rectifier formed by D1 through D4 and filter capacitor C1. A battery backup is provided if the mains supply is cut-off due to short-circuit and fire. A 12V, 4.5Ah rechargeable battery is used for backup to give sufficient current to the solenoid pump. 

When mains power is available, diode D5 forward biases. It provides power to the circuit and also charges the battery through resistor R2, and it limits the charging current to 120 mA. When power fails, diode D5 reverse biases and diode D6 forward biases, giving instant backup to the circuit. LED1 indicates the availability of mains power.

Assemble the circuit on a general purpose PCB and enclose it in a suitable case. Connect the piezo element to the circuit using a thin insulated wire. Glue the flat side of the piezo elto the circuit. LED1 indicates the availability of mains power.

Assemble the circuit on a general purpose PCB and enclose it in a suitable case. Connect the piezo element to the circuit using a thin insulated wire. Glue the flat side of the piezo element on a 30×30cm aluminium sheet to increase its sensitivity. Fix the sheet with the piezo sensor to the site where protection is needed. The remaining circuit can be fixed at a suitable place. If only the alarm generator is needed, omit the relay driver section.

Fig. 1: Pyroelectric fire sensor Figure 2: Power Supply



Wednesday, June 9, 2010

Lasers in Angioplasty/Angiography

Laser Angioplasty


Angioplasty
Angioplasty is used to widen arteries, which are narrowed by stenoses or occlusions. This procedure is helpful in many ways, like, clearing of plaque from coronary arteries, emergency relief from a heart attack that is in progress, and widening narrowed arteries in limbs, such as the femoral or iliac artery to the leg. It is also useful in relieving chest pain, caused by narrowing down of coronary arteries. Angioplasty performed earlier was done by dilating the blood vessel with the introduction of larger stiff catheters, through the narrowed space. However, complications involved in this procedure gave motive to scientists and researchers, to develop a means of widening the vessel using a minimally sized device. Now lasers may be used to assist in the break up of fat or calcium plaque and catheters may also be equipped with spinning wires or drill tips to clean out the plaque.

Laser Angioplasty
In the laser angioplasty technique, a thin and flexible plastic tube called a catheter, with a laser at its tip, is used. It is inserted into an artery that opens into coronary arteries blocked by plaque, a build-up of cholesterol, cells and other fatty substances in an artery's inner lining. Then the plastic tube is advanced through the artery to the blockage in the coronary artery, and it emits pulsating beams of light from where the laser is in position. These lasers help in vaporizing the plaque. The laser technology can be used alone, or in combination with balloon angioplasty. If used along with balloon angioplasty, the balloon is inserted first to attack the hard plaque.

In laser angioplasty mostly eximer laser is used.

Eximer Laser

An excimer laser (sometimes, and more correctly, called an exciplex laser) is a form of ultraviolet laser which is commonly used in angioplasty, eye surgery and semiconductor manufacturing.

The term excimer is short for 'excited dimer', while exciplex is short for 'excited complex'. An excimer laser typically uses a combination of an inert gas (argon, krypton, or xenon) and a reactive gas (fluorine or chlorine).

Under the appropriate conditions of electrical stimulation, a pseudo-molecule called an excimer (or in case of noble gas halides, exciplex) is created, which can only exist in an energized state and can give rise to laser light in the ultraviolet range.

Lasers in Endoscopy

Lasers in Endoscopy


INTRODUCTION

Laser, the acronym for Light Amplification by Stimulated Emission of Radiation is merely a beam of ordinary light radiation. Visible light which is a day-to-day experience in our natural environment, represents only one facet of a much broader physical phenomenon known as electro-magnetic radiation.

The unique properties of laser radiation that differentiates it from ordinary light are:

a. It is monochromatic as it is made up of identical atoms all emitting photons of the same wave length.

b. It is coherent

c. The beam being parallel to the longitudinal axis of the tube features a very low angular divergence.

The clinical implications of these properties are far reaching and allows the surgeon to focus the beam precisely on the target area.

In the hands of a skilled surgeon, the laser becomes an instrument capable of inducing desired therapeutic effects, far beyond the scope of conventional surgical tools such as cold knives or electro cautery probes. Precise incision can be performed, lesions extending over large areas can be vapourized, voluminous lesions can be debulked and destroyed by ablation or necrotization.

Laser energy can be delivered to tissue in a variety of ways: by contact or from a distance. In majority of cases, laser provides a largely haemostatic effect where the surgeon enjoys the convenience of a dry and clear field. Moreover the extent of injury to the surrounding tissue is to a high degree controllable. The laser enables the surgeon to reach anatomical structures whose size or location render them inaccessible to any other known surgical instrument. Consequently the post operative complications, pain or irreversible damage is reduced considerably.

The properties which make laser so unique are:

 High precision of incision

 Controlled depth of penetration

 Minimal bleeding

 Minimal damage to adjacent structures

 Better healing with minimal scar tissue

 Less post operative pain

Commonly used lasers in gynaecology are carbon dioxide and ND: YAG (Neo Dynium Ytrium Aluminium Garnet) Lasers.

The CO2 laser features a wave length of 10.6 microns in the far infra red range. It is strongly absorbed by water. CO2 laser is readily absorbed by the first twoellular layers of tissue, constituting the first 100Mm. Consequently this is a laser used for superficial treatment.

The various limitations of CO2 laser are:

• Need to use a cumbersome instrument

• Inability to work in liquid medium, hence it cannot be used in hysteroscopy

• Excessive smoke production.

Nd: YAG laser features a wavelength of 1.06 Mm (near infra red) It creates a deep and laterally extended ball of affected tissue, 3-5 mm in diameter. Nd: YAG laser is ideal for the treatment of lesions located in liquid filled cavities such as the bladder and the uterus filled with a distension liquid, as water is completely transparent to this type of radiation.

The various conditions in which lasers can be used in gynaecology are infertility, chronic pelvic pain, endometriosis, ectopic pregnancy and fibroids.

Laser in ophthamology

Therapeutic application of lasers in ophthalmology (Do any two)

Misiuk-Hojlo M¹., Krzyzanowska P.¹, Hill-Bator A.¹

¹ Department of Ophthalmology, Wroclaw Medical University, Poland




Laser effects in biological tissues can be divided into three general categories:

photochemical, thermal, and ionizing.

With the improvement of laser technology, the techniques with using different types of lasers (ruby, neodymium, neodymium: yttrium-aluminum-garnet, erbium, and argon) allowed to utilize lasers in the treatment and diagnostics of many eye disorders.

Photoradiation takes place when photosensitized tumor tissues are exposed to laser light for the purpose of producing photochemical damage. During photoablation, tissue is removed in some way by light, such as when intermolecular bands of biological tissues are broken, disintegrating target tissues, and the disintegrated molecules are volatilized. This can
be effected with, for example, excimer laser.

Photocoagulation causes denaturation of biomolecules when temperatures are
sufficiently high, about 600C or more. Temperature rise in tissues is proportional to the amount of light absorbed by that tissue. Absorption of certain light frequencies is high in pigmented trabecular meshwork, iris, ciliary body, and retinal pigment epithelium (owing to melanin), and in the blood vessels (owing to hemoglobin). Lasers commonly used
photocoagulation are argon, krypton, or diode Nd:YAG lasers.

Photovaporization occurs when the tissue temperature quickly reaches the boiling point of water, causing disruption (evaporation) before denaturation (photocoagulation).

Examples of clinical uses of these lasers are holmium: YAG or erbium: YAG laser sclerostomy.

In photodisruption, short-pulsed, high-power lasers disrupt tissues by delivering enormous irradiance to tissue targets. The high level of irradiance ionizes molecules in a small volume of space at the focal point of the laser beam, disintegrating into collections of ions and
electrons called plasma. This plasma expands rapidly, producing shock and acoustic waves that mechanically disrupt tissues adjacent to the region of laser focus.

Examples of photodisrupter lasers are the Q-switched and pulsed Nd:YAG laser.

Glaucoma laser treatment is often recommended when medical therapy alone is insufficient in controlling intraocular pressure, for those patients who have contraindications to glaucoma medications or, for any reason, are unable to use eye drops.

The most common glaucoma laser procedure is laser peripheral iridotomy (PI). A laser iridotomy is performed for patients with narrow angles, acute angle closure glaucoma, in the fellow eye of a patient with acute or chronic primary angle closure, or pupillary-block
glaucoma.

Laser peripheral iridotomy involves creating a tiny opening in the peripheral iris, allowing aqueous fluid to flow from behind the iris directly to the anterior chamber of the eye. This typically results in resolution of the forwardly bowed iris and thereby an opening up
of the angle of the eye.

There are two types of lasers in use today - Nd:YAG Q-switched
laser (2 – 8 mJ) or argon laser (800 – 1000 mW). Argon laser began to replace surgical iridectomy as a safer, non-invasive method of making an iridotomy in the late 1970s. It was demonstrated to be safe and effective, but required melanin for tissue absorption of the
energy, making it less easy to penetrate lightly pigmented blue irides.

The Nd:YAG laser replaced argon as the most common means of performing LPI in the late 1980s. The Q -switched mode of the Nd:YAG laser causes photodisruption of tissues by the formation of energy ionic plasma at the location of focus of very intense energy. It has the advantage
of not requiring the presence of melanin pigment for iris absorption.

Complications of laser iridotomy include: irritation, blurred vision, iritis, iris hemorrhage, elevated intraocular pressure, corneal injury or retinal burns.

Argon laser trabeculoplasty (ALT) is a procedure which has been proven to be efficacious for different types of open angle glaucoma: primary open angle glaucoma, pseudoexfoliation glaucoma and pigment dispersion glaucoma. Patients with poor medical compliance can benefit from ALT before other surgical intervention is considered.

In the ALT procedure, the eye surgeon directs a laser beam into the trabecular meshwork, which is the primary aqueous (fluid) drainage region of the eye. In most cases, 180 up to 360 degrees of the trabecular meshwork is treated with laser spots, which typically requires about 40 to 80 laser applications. The effect of the procedure is increased drainage of aqueous fluid out of the eye and intraocular pressure reduction to 20 – 25%. Efficacy of the ALT procedure lasts for about 5 years.

Modification of this procedure is selective laser trabeculoplasty (SLT) performed with a Q-switched 532 Nd:YAG laser. SLT works by using a specific wavelength to irradiate and target only the melanin-containing cells in the trabecular meshwork, without incurring collateral thermal damage to adjacent non-pigmented trabecular meshwork cells and
underlying trabecular beams. The laser beam bypasses surrounding tissue leaving it undamaged by light. This is why, unlike ALT, SLT is repeatable several times. Indications for this procedure and complications (intermittent intraocular pressure elevation, iritis or
heamorrhage) are similar like in ALT.

Another glaucoma laser procedure is argon laser peripheral iridoplasty (ALPI). ALPI is a method of opening an appositionally closed angle in situations in which laser iridotomy either cannot be performed or does not eliminate appositional angle-closure because mechanisms other than pupillary block are present. The procedure consists of placing
contraction burns of low power, long duration, and large spot size in the extreme iris periphery to contract the iris stroma between the site of the burn and the angle, physically pulling open the angle. ALPI is recommended in plateau iris syndrome, or angle closure
glaucoma. The argon laser is set to produce contraction burns (500 µm spot size, 0.5 to 0.7 second duration, and, 200-400 mW power).

Cyclodestructive procedures in glaucoma lower the intraocular pressure (IOP) by reducing aqueous inflow as a result of distruction ciliary processes. The use of light energy to ablate the ciliary body was first proposed by Weekers and co-workers in 1961 using xenon arc photocoagulation In 1972 Beckman and Waeltermann performed the first
transscleral cyclophotocoagulation (TSCPC) procedure with the ruby laser. Since then, the neodymium (Nd):YAG and diode lasers have been used for transscleral cyclophotodestruction. Due to the high complications rate, and the unpredictability of the amount of IOP reduction, these procedures are usually reserved for the following conditions:
eyes with glaucoma refractory to other forms of surgical or medicinal therapy, eyes with poor visual potential, neovascular glaucoma, traumatic glaucoma, aphakic and pseudophakic glaucoma, chronic partial or total angle-closure glaucoma, aniridia or iridocorneal endothelial
syndrome.

Light coagulation and laser treatment of the retina were introduced to ophthalmology around middle of the last century. They are widely used for the treatment of diabetic retinopathy and other ischemic retinopathies. Retinal laser photocoagulation improves inner retinal oxygenation, which affects retinopathy through the relief of hypoxia and consequent
change in growth factor production and hemodynamics.

Diabetic retinopathy is a leading cause of visual loss in industrialized countries. Its classification includes preclinical, nonproliferative (mild, moderate, and severe or preproliferative diabetic retinopathy) and proliferative stages (low risk, high risk, and advanced). Diabetic maculopathy (exudative, edematous, or ischemic) may be associated with
either nonproliferative or proliferative retinopathy. Prevention requires the tightest possible control of both blood glucose and blood pressure. Laser photocoagulation remains the only procedure recommended for severe nonproliferative or proliferative retinopathy and maculopathy. (14) The Diabetic Retinopathy Study (DRS) showed that the rate of severe
visual loss in high- risk proliferative diabetic retinopathy could be reduced by as much as 60% following the timely application of panretinal laser photocoagulation therapy.

Results from the Early Treatment Diabetic Retinopathy Study (ETDRS) demonstrated that focal laser photocoagulation treatment to the macula region could substantially reduce the risk of visual acuity loss in patients with clinically significant diabetic macular edema.

Retinal vein occlusion (RVO) is a common retinal vascular disorder that frequently is associated with severe visual loss. There are two forms of retinal vein occlusion, branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). A branch retinal vein occlusion is essen tially a blockage of the portion of the circulation that drains the retina
of blood. Central retinal vein occlusion is closure of the final retinal vein (located at the optic nerve) which collects all of the blood after it passes through the capillaries. There is presently no effective treatment available to prevent or restore the visual loss from acute CRVO.

Following a vein occlusion, the primary concern is to treat the secondary complications: macular edema, macular ischemia (non -perfusion) and neovacularization (growth of new abnormal blood vessels). Argon or diode l aser treatment may be useful in managing these complications. One type of laser treatment, focal laser, can be used to close off areas of
leakage from the blood vessels that cause macular edema. Another type of laser treatment, panretinal photocoagulation, can cause neovascularization to regress by making the retina less starved for oxygen.

Nowadays, laser treatment is also available in the age-related macular degeneration (AMD), a disease of our civilization. Macular degeneration is a progressive eye condition affecting the central vision and causing irreversible blindness in people over the age of 50. AMD has two basic forms: dry and exsudative. Dry AMD accounts for about 90% of cases, is
the milder form of the disorder. Exsudative AMD is the much more visually debilitating form of macular degeneration, often accompanied by choroidal neovascular membranes, which are the leaky vascular structures under the retina. There are two basic forms of laser treatment for exsudative AMD: conventional argon or diode laser therapy and the recently approved photodynamic therapy (PDT). Conventional laser burns the abnormal blood vessels and thus stops the leakage. However, since it also damages the normal retina structures, it may itself lead to decreased vision. Hence, it is suitable only in selected cases where the new vessels are
not very close to the central macular area.

The concept of the new treatment for exsudative AMD is the closure of subretinal choroidal neovascularization (CNV) without significant
damage to the surrounding tissues, such as photoreceptors or retinal pigment epithelium (RPE).

In PDT, a photosensitizer, Verteporfin is administered intravenously and allowed to perfuse the CNV, as well as the remainder of the body. Fifteen minutes after the start of intravenous infusion, the verteporfin is activated by a red laser of a specific wavelength (689nm). The non -thermal laser light activates the verteporfin producing the singlet oxygen
that both coagulates and reduces the growth of abnormal blood vessels. This, in turn, inhibits the leakage of fluid from the CNV.

The first attempts to treat intraocular tumors by means of photocoagulation were carried out in the late 1950s by G. Meyer-Schwickerath with the xenon arc photocoagulator. (13) Nowadays, lasers are an irreplaceable tool in the management of malignant and benign
intraocular lesions. Transpupillary thermotherapy (TTT) using an 810nm i nfrared laser has become one of the most popular treatments for small melanomas. Lasers can be also used as an adjunctive tool in combination with other treatment modalities in therapy regimens for
medium or even large melanomas. The main advantages of laser treatment compared to other modalities like irradiation are the broad availability, the relatively easy performance and thus reproducibility, the high precision during the treatment, and the safety for the adjacent tissues.
Corneal laser surgery with the modern excimer laser is known to be the most frequently applied laser procedure in medicine. The interaction between corneal tissue and the excimer laser was first investigated in 1981 by Taboada, who studied the response of the epithelium to the argon fluoride (AF) and krypton fluoride (KrF) excimer laser. (19) The use
of lasers to reshape the anterior corneal curvature to correct refractive errors has become an established clinical procedure.

Surgical techniques such as photorefractive keratectomy (PRK) and laser in-situ keratomileusis (LASIK) are used to correct optical aberrations of the eye, such as myopia or hyperopia, as well as astigmatism. During PRK for the correction of myopia, direct flattening is achieved by the removal of a convex-concave lenticule of tissue from the outer surface of the central cornea. Clinical studies determined refractive success
rates of between 80 and 95% for corrections up to –6 D of myopia. (18) A modification of this technique involves the microkeratome to make a lamellar flap (average thickness, 120-160 mm) of anterior corneal stroma, followed by refractive ablation of the exposed stromal bed.
This flap is then repositioned on the exposed stroma, and good adhesion is usually obtained without the need for sutures. This procedure was particularly investiga ted in eyes needing high myopic corrections if more than – 6 D.

In the recent years, a new method has been developed and used. This is called laser subepithelial keratectomy (LASEK). (3) In this procedure, the epithelial layer is completely removed, but about 900
of the circumference is allowed to remain as a short of hinge. After
the laser treatment, which is equivalent to PRK, the epithelium is replaced.

Laser photocoagulation is also mainly used in the retina abnormalities such as: tears, breaks, holes, lattice degeneration or retinoschisis, which predispose to a rhegmatogenous retinal detachment. With argon laser photocoagulation a thermal burn is created to surround the lesion and any subretinal fluid associated with it. The burn becomes an adhesion between
the retina and retinal pigment epithelium, and this limits potential flow of fluid from the vitreous cavity through a break.
Visual loss occurring secondary to opacification of the posterior capsule after extracapsular cataract extraction is the major indication for laser capsulotomy. Posterior capsulotomy for creating openings in an opacified posterior capsule can be performed with the argon laser of the pulsed Neodymium-YAG laser.

It is impossible to imagine ophthalmology today without lasers, ubiquitously and thoroughly do they dominate the field. A rapid explosion of argon laser techniques occurred in the late 1970s and early 1980s. In the 1990s, another explosion occurred in the treatment of posterior segment disorders, including macular degeneration and intraocular tumors.

The development of lasers for plastic surgery, cataract extraction, and ocular imaging is progressing rapidly and is expected to find much greater use and usefulness in the coming years.

Monday, January 18, 2010

Co-Evolution of Man and Machine: Neuroprosthetics in the 21st Century




NEUROPROSTHETICS IN 21ST CENTURY



Promise of Neuroprosthesis



Develop communications pathways between the brain and external devices to restore lost sensory, motor, or other internal
neural function.                         



Use the device to bypass injury or aid  in rehabilitation



Direct contact with body’s command and control systems



Seamless, intertwining of electronics, mechanics and materials.



Biomimicry : Closely replicates physiological function.      





              Figure 1



 



THE 21ST CENTURY BIONIC HUMAN





Figure 2



TRANSLATING THOUGHTS INTO ACTIONS  : THE NEURAL CODE



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Figure 3



 



THE NEUROPROSTHESIS DESIGN



Neural Information Processing , Adaptive Signal Processing , Feedback Control  



 





Figure 4



 



THE NEUROPROSTHESIS DECODING THEORY



Supervised and Unsupervised learning have been the key players in BMI design.



 





Figure 5



THE NEXT GENERATION BRAIN - MACHINE INTERACTION



Intelligent behavior arises from the actions of an individual  seeking to maximize received  reward in a complex and changing world.





Figure 6



Perception-Action Cycle:  Adaptive, continuous process of using sensory information to guide a series of goal-directed actions.



THE NEW FRAMEWORK



Co-Adaptive BMI involves TWO intelligent  agents involved in a continuous dialogue!!!





Figure 7





Figure 8



 



THE INFORMATION IS TAKEN FROM



Co-Evolution of Man and Machine: Neuroprosthetics in the 21st  Century



Justin C. Sanchez, Ph.D.

Assistant Professor

Neuroprosthetics Research Group (NRG)

University of Florida

http://nrg.mbi.ufl.edu 

jcs77@ufl.edu




Sunday, January 10, 2010

Biogas Generator : A Renewable Energy Project Kit

Build Your Own Biogas Generator : By The Pembina Institute


File : 1



File : 2



File : 3





File : 4







File : 5















Thursday, January 7, 2010

BRAIN SENSE - The Preface


BRAIN SENSE - By Faith Hickman Brynie

It makes a very good reading...

The Preface : Falling in Love with Science


I don’t recall when I first fell in love with science, but I remember the day when I said, “’Til death do us part.” I was counting raspberry bushes. They grew wild around the abandoned strip mines of Appalachia. As an ecology student at West Virginia University in Morgantown, I clambering around an old mine’s precarious slopes with twenty other eager undergraduates. We shot line transects and counted the bushes, orienting our test sites by the compass, while measuring roped-off segments ten-meters square for careful counting and mapping. The day was hot and sticky. The prickly bushes tore our clothes and gouged our flesh. Black coal dust clogged our lungs. Sunburned and sweaty, we learned
that wrestling truth from reality was difficult . . . and fun!

Field science infatuated me that day, but my pledge of lifelong devotion to
the scientific process came a few days later, when we pooled data from several
teams. We made graphs of numbers of raspberry bushes, north and east, upslope
and down. The graphs sang to me. Their meaning popped off the page and danced
around my desk. In axes, points, clusters, and lines, the numbers of raspberry
bushes revealed the history of the mine. In the days long before ecology became
a household word, those bars, dots, lines, and curves mirrored the fifty-year history of the mine, disclosing how the site had been worked, when it had been
abandoned, where the acid mine drainage had polluted most, and how nature
had attempted—with wild raspberries—to bandage the land so it could heal from
within. The data painted a picture more beautiful to me than any art museum
masterpiece.

From that day on, I never questioned my choice of a career. It was science
for me, in some form, and I’ve tried quite a few. In the bacteriology labs at WestVirginia University, I grew on agar culture plates the acidophilic microorganisms that can survive in acid mine drainage when nothing else can. At Oak Ridge National Laboratories, I zapped protozoans with ultraviolet light to see if they would die. They did. At West Virginia University Medical Center, I worked under a grant from the U.S. Army, screening the effects of possible new malarial drugs on blood samples run through a labyrinth of tubes, reaction vessels, and colorimeters. (Computers do all that now.) In Colorado, I mixed reagents for thyroid tests in a medical lab. I stuck thermometers down prairie dog burrows in Rocky Mountain National Park, and I set up anemometers in mountain meadows.
Then I got into science teaching and educational reform because I wanted every
young person to fall in love with science just as I had. Writing curriculum and
designing educational materials led me into topics ranging from medical genetics
to land use planning.

In the early 1990s, I read a sentence that riveted my attention. The neuroscientist
Richard Restak wrote, “The [human] brain is the only organ in the known
universe that seeks to understand itself.”1 That sentence stopped me dead in my
tracks. Here was the science of science itself—an organ of tissue and blood attempting to understand its own functioning. To my mind, that was bigger than
malaria drugs, bigger than burrowing animals, bigger even than my raspberry
bushes. I couldn’t wait to find out what neuroscientists were doing with their
brains as they attempted to comprehend . . . their own brains! So I started digging
though the scientific literature and eventually I wrote a book called 101
Questions Your Brain Has Asked About Itself But Couldn’t Answer . . . Until Now.
The book was moderately successful, garnering a “Best Book” honor from the
American Association for the Advancement of Science in 1999. The book is now
in its second edition and continuing to make a contribution, I hope.

For me, however, one hundred and one questions formed only the tip of the
iceberg. The more questions I asked and the more I read and learned, the more
I wanted to know. I became fascinated with research on how the brain and senses
interact—thus this book’s title, Brain Sense. “Brain sense” is a field that many
tillers are plowing: the neurologists who study the interaction of peripheral and
central nervous system; the brain mappers who chart the regions of the brain that
handle specialized functions and the nerve networks that connect those regions;
the biochemists who probe the molecular receptors that initiate the impulses
of the chemical senses; the biophysicists who explore how light and sound waves
can sometimes translate themselves into sensory perceptions; the physicians and
surgeons who seek to treat the maladies that befall the senses and the brain; the
engineers and biomechanicists who try to understand how perception works so
they can construct devices ranging from prosthetics to virtual reality simulators;
the cognitive psychologists who want to understand how we learn; the behavioral
psychologists who hope to explain why we do the things we do; and the clinical
psychologists who strive to cure the intellectual, social, and emotional sequelae
of sensory perception gone awry.

The organization of this book follows traditional lines. There’s a part on each
of the five major senses: touch, smell, taste, vision, and hearing. The book begins
with touch because, in my opinion, it’s the least appreciated of all the senses
and perhaps the most vital. We explore the chemical senses next, because taste
and smell work in similar ways. Next come sight and sound, the senses that we
rely on the most and can trust the least.

In the individual chapters about each sense, I’ve tried to include some stories
about how ordinary people live when their sensory capacities are diminished
or lost. I’ve also included as much of the latest in scientific research as I could
jam onto each page. There is so much going on in brain-sense research, I can
scarcely scratch the surface here, but I hope that the studies I’ve chosen for inclusion impart some sense of the endless fascination of that work.

Throughout these chapters, you’ll notice two recurring themes. The first is
brain plasticity. Plasticity means that the brain changes throughout life. Once,
we thought of the adult brain as fixed and unchanging (except for the deterioration that comes with age), but research in the last two decades has shattered that notion. The brain is constantly rewiring itself, reshaping its own structure, recruiting new circuits to perform its work when old ones are damaged or lost.

It even re-creates memories each time it retrieves them. The implications of brain
plasticity for understanding our senses, our consciousness, and the essence of
what it means to be human are nothing short of staggering.

The second theme is what I’ve come to think of as a negotiable reality. We
believe in our senses, and we trust that they are providing us with objective, complete, and accurate data about the world around us. We are wrong. Our brains
construct our reality, molding every input to what we expect, what we imagine,
what we wish for. Our brains have minds of their own. They shape light waves
into expected images, sound waves into patterns ranging from noise to music.
Our sense of touch is malleable, variable, and refinable. We taste and smell what
we believe we will taste and smell. In precisely the same environment, you and
I will neither see, hear, taste, touch, nor smell the same things—nor will we draw
the same conclusions about the information our senses have collected. Our personal worlds are constructions built by our brains using the raw materials of the senses—raw materials that are greatly modified during the construction process.

That idea of a negotiable reality is the reason for the last part of this book,
“Beyond the Big Five,” which looks briefly at some of the other “senses” or sensory
experiences that don’t fit with the big five but are too intriguing to ignore,
such as the mingling of the senses known as synesthesia, the experience of déjà
vu, the phantom sensations and phantom pain often experienced by people who
have amputations, the possibilities and probabilities of extraordinary sensory perception, and the brain’s sense of time kept by a body clock far more precise than most of us realize.

I hope that people who know a lot about the brain and the senses will read
this book. I hope that people who know very little about those topics will read it,too.

For those readers who are interested in the brain and the senses but don’t
know much about the brain’s structure and function, I’ve included an appendix
at the end of the book, “The Brain and the Nervous System—A Primer,” which
provides a short course in neuroscience and explains many of the terms and concepts used in this book. It also includes diagrams showing the locations of many of the brain regions discussed in the book. Before long, you’ll know your occipital lobe from your parietal, and you’ll be well on your way to comprehending your own “brain sense.”

From beginning to end, this book is many things. It’s part memoir because
it’s my opportunity to reminisce about some things I’ve learned from science and
from life. It’s part investigative reporting because I’ve delved into the work of some cutting-edge researchers who are designing clever experiments to gain answers to questions that we didn’t even know how to ask a decade ago. It’s part biography because I want you to know—as I have come to know—what real scientists are like as they work in real labs on real questions that have never before been answered. It’s part textbook because basic knowledge about how our senses work is important to everyone. It’s part history because we can’t appreciate where we’re going if we don’t value where we’ve been. It’s part newspaper because it contains some of the late-breaking stories that are making headlines on a daily basis. It’s part travel journal because I invite you to fly with me as I visit working neuroscientists in Washington, Minnesota, Michigan, and Massachusetts. It’s part
personality profiles because the scientists I met and talked with are intriguing
people, doing interesting work and living full and satisfying lives. I want readers
of this book to see scientists as I have seen them—not as geeky weirdos in lab
coats, but as warm, humorous, engaging human beings who thrive on the search
for knowledge as they toil among the “raspberry bushes” of their chosen research
specialty.

Most of all, this book is a tribute to courage and to some of the wonderful
people who shared their stories with me: the tour guide who faced death as her
ship sank in Antarctica; the hairdresser who lost her sense of smell to brain injury; the woman who had a mastectomy but continues to feel her breasts; the
young poet, born deaf, who had a cochlear implant; the synesthete who sees letters in colors; the electronic genius who engineers phone lines and ignores his
tinnitus; the teenager who was born without the sense of touch and the mother
who has loved him totally and unconditionally through all he has achieved.
Finally, this book is a love letter to science and scientists. I’ve been wedded
to science all my life, and my fascination with the questions, methods, and inferences of scientific research has never diminished. Science isn’t the only way
to see, to know, to understand, but it’s the one that won my heart. Come meet
the love of my life.




Tips to master the Web

Tips and Tricks - MASTER THE INTERNET

Save time as you shortcut your way through the Internet with these nifty, must-know tricks

1. Receipt notification

If you have a really important message and need to know if it’s been received, use a feature called Read Receipt in Outlook Express. This feature is available on most e-mail clients and requests the recipient to confirm that he has received the message by a return e-mail.

To do this while composing a mail in Outlook Express, click on Tools > Request Read Receipt in your message window. If you desire, you can have all your outgoing messages sent with the Read Receipt notification. For this, go to Tools > Options, click on the Receipts tab and tick ‘Request a read receipt for all sent messages’. Remember, the read receipt confirmation is dependent on the e-mail client the recipient is using and also whether he wants to send the confirmation.

2. Adding signatures to your e-mail

If you send a lot of mail each day, then a repetitive task like signing your name at the end of each mail can be quite tedious. It’s easier to create a signature and attach it automatically to every mail that’s sent. To do this in Outlook Express, go to Tools > Options > Signatures. Then go to New and add the contents of the signature in the Edit Text field. Also select the option of sending the signature automatically with all outgoing messages. In case you don’t want to send this with replies or forwards, enable the option, ‘Don’t add signatures to Replies and Forward’. For creative signatures, use the option to append a file that contains the signature you have created. If you happen to have multiple e-mail accounts, select the account with which you want to send the signature. To do this, go to Tools > Options > Signatures and click on the Advanced button near the Edit Signature tab. A new box will appear saying ‘Advanced Signature Settings’ where you can select the account with which the signature should be automatically added.

3. Auto-respond facility

Won’t be checking mail for some time? Activate a feature called ‘vacation reply’ (if you are using a Web-based service). Most e-mail services such as Indiatimes provide this feature which can be activated through the options menu. You can type a short message which will be sent to all who e-mail you while you are away. In Outlook Express, you can do this from Tools > Message Rules > Mail and clicking on the New Rule option. Select the ‘For all Messages’ options from the condition for your rule field and in the Action select Reply with a message. You will have to select a message that you have already created and saved.

4. Keep a copy of the message

If you are on a trip and want to access your e-mail from another machine, keep a copy of your messages on the server of your e-mail service provider. Go to Tools > Accounts and select the account (if you have multiple accounts), then go to Properties > Advanced. Check ‘Leave a copy on server’. This has one more advantage: if you’ve formatted your machine without taking a backup of your mail, you can retrieve the mail as a stored copy.

5. Disable MSN Messenger from auto-starting

Whenever one opens Outlook Express or Microsoft Outlook XP, MSN Messenger loads automatically. To disable it, go to Tools > Options in Outlook Express and uncheck ‘Automatically log on to MSN Messenger Service’. Then go to View > Layout and uncheck the option of Contacts. In Microsoft Outlook XP, go to Tools > Options > Other and uncheck ‘Enable MSN Messenger’. The over-eager Messenger won’t be so eager now!

6. Optimising your Inbox

A three-step process to ensure that your Inbox never looks cluttered.

1. Organising: Outlook Express allows you to create folders within which mail can be organised. To create a new folder in Outlook Express, go to File > Folder > New. This will display the directory tree of your Inbox. Just select the location (say Inbox) where you want to create a folder and enter the Folder Name. Or, you could use the shortcut [Ctrl] + [Shift] + [E] and enter the Folder Name. You can also drag and drop folders to change their location. Folders can be quite useful, especially if you have multiple accounts configured on the same identity or to sort out e-mail messages on the basis of sender, subject, etc.

2. Filtering: Message Rules can automatically sort your mail into the appropriate folder as soon as it is downloaded. Specify the folders where you want the messages to be downloaded based on names in the From address, names in the To address, certain words in the Subject line or in the message body.

Go to Message > Create Rule From Message. Create a rule selecting the appropriate options offered, and the next time you download your mail, it will be sorted according to the rules created.

You can also sort your existing messages based on the message rules created. In Outlook Express, go to Tools > Message Rules and click on Mail. You will get a list of the message rules you have created. Click on ‘Apply Now...’, select the rules to apply, and click on Apply to filter your existing folder.

3. Grouping: Outlook Express allows you to group e-mail messages on the basis of the conversation carried. To enable this, go to View > Current View and click ‘Group Messages by Conversation’ (In Outlook, this option is available from View > Current View > Conversation Topic).

With this feature, all e-mail messages are sorted on the basis of the subject line and the messages that are a reply to that particular subject are grouped together. A ‘+’ sign next to a message indicates responses based on that subject.

7. Download Mail to your PC

If you use a Web-based e-mail service, such as those run by Yahoo! and MSN, download a copy of your mail directly to your browser. This is much quicker than using the bandwidth-hungry Web interface and also allows you to access your mail without having to be connected to the Internet. To do this first add a new account by going to Tools > Accounts > Add and select the Mail option. You will be prompted for personal details and account information.

Select the POP3 server option in the screen that asks you for your e-mail server information and enter the appropriate POP3 server address for incoming mail.

8. Browsing offline

Quite often you may want to refer to a page that you have visited at some point in time. While finding the link in your browser’s History is not too difficult, you can view the site without actually logging on to the Internet by going to File > Work Offline. Then just click on a link in your History folder to view the complete page from your hard disk.

9. PC-to-PC calls

Buddy Phone, Yahoo! and MSN Messenger allow users to make phone calls from one computer to another, provided both computers are online. If you would like to use this facility in MSN Messenger, select your friend’s name from the list and go to Actions > Start a voice conversation. This can also be done by right-clicking on the person’s name and selecting the option of ‘Start a Voice Conversation’. After the opposite person has accepted your request, you can start talking into the microphone.

10. Split files

Splitting files can increase download speeds tremendously in FlashGet. Usually, splitting the file in three or five segments is sufficient. However, if you are downloading a particularly large file which is available from several servers, you could get better speeds by increasing the number of segments being downloaded simultaneously.

The number of segments that you want the file in can be set in the option box that pops up when a download begins. Just set the option for the number of segments that you want the file to be split into.