We vessels can be divided into three main groups in terms of structure and function. The ones with thicker walls, which bring every organ the blood they need from the heart, are the arteries. The pressure inside us is higher and we easily carry blood to the organs. The ones with thinner walls, lower pressure, and larger inner space are called veins. As a matter of fact, both arteries and veins have a three-layered structure that is very suitable for holding a fluid like blood. Since our walls are strengthened with both connective tissue and smooth muscle layers, we bear the pressure coming from the heart and help blood proceed by contracting and relaxing. Since arteries are directly subjected to the strong pressure from the heart, our walls were created in a thicker and stronger form. Since the veins return blood to the heart and thus have lower pressure, we have valves that close after blood passes, so it does not flow backward due to gravity. This is a serious challenge for the blood passing through your legs. Varicose veins might develop due to weight gain from pregnancy or obesity, which increases pressure on the legs, or to hours of standing, walking, or running on hard surfaces.

Capillaries are the most delicate blood vessels, with walls made of a single layer of epithelium, which enables us to exchange substances between blood and tissues. As blood vessels, our total length is about 120,000 kilometers. Try to imagine if a fisherman’s net were made from a rope of this length and how wide it would be! And yet, such a vast network of blood vessels is located in your body, and capillaries take blood to every part, without neglecting an area as tiny as the head of a pin.

The well-being of your organs is directly related to us. If our interiors begin to narrow, because of fatty cholesterol plaque for instance, then we begin to lose our flexibility. This means malnutrition for that organ, since a lesser amount of blood than expected can come. If a blood clot sticks to our wall and blocks the blood flow, the relevant organ may be in terrible trouble. If other arteries supply blood to that organ, then it can handle this, but if a main artery is blocked and if secondary channels do not exist or are insufficient, you experience infarction. Taking this into consideration, you need to be careful what you eat and lead a physically active life. When you get old, if sufficient blood does not pass through us in your brain, failures with brain activities appear and you go senile. As the walls of veins and arteries have a rich network of nerves, we let the suitable amount of blood flow according to the need of the organ we’re serving, under the control of the autonomous nervous system. While blood vessels that are connected to an organ not currently requiring much blood contract to reduce the amount supplied, those that are connected to currently more active organs expand. And dear Peter, the greatest blessing here is that none of these activities require any conscious effort from you; everything works smoothly without your even being aware.

This wonderful network of ours finds its value in the vital fluid we carry. If it weren’t for blood, we would have no value at all, and such a perfect means of distribution would be unnecessary. Even the duty of the heart is to make this fluid circulate throughout the body. Now, let us step aside and allow blood to have the floor.

The problem of pulmonary tuberculosis in pregnancy has attracted the attention of doctors for many years and it is still a current issue. Modern researchers and physicians divide tuberculosis into several independent problems which have difficult solutions. On the one hand, there is the influence of tuberculosis on the course of pregnancy and child delivery as well as on the health of a mother and her child. On the other hand, there is the influence of pregnancy and childbirth, the puerperal period and lactation on the course and progress of tuberculosis.

Research on how pregnancy influences the course of tuberculosis has been carried out for many years. Even in the oldest available documents we can find instructions for “personal precautions” and preventative measures against tuberculosis, as well as thoughts about pregnancy and tuberculosis. In 1400 BC the Law of Manu from ancient India prohibited marriages to girls from families with tuberculosis. In different world religions, including Islam and Christianity, there are special restrictions concerning people who suffer from this illness.

In ancient times Hippocrates and Galen taught that pregnancy has a positive influence on the function of lungs. But the Islamic doctors, Arabian as well as Spanish, of the Cordoba Caliphate considered that the blessed process of pregnancy must not be complicated by pulmonary diseases.

With time European medical science changed its point of view. From the second part of the 17th century until the beginning of the 19th century doctors considered that pregnancy had a bad effect on the course of tuberculosis, but then the situation, for some reason, changed. Doctors began to think that pregnancy had a good influence on lung diseases. They even started to advise girls who were susceptible to tuberculosis to marry. Time passed and doctors began to change their opinion on tuberculosis in pregnancy and the extremes in views became less obvious. This happened due to the introduction of an artificial pneumothorax into the treatment of tuberculosis.

Since then the third period in the understanding of the relationship between pregnancy and tuberculosis has begun. The opinion about the course of tuberculosis in pregnant women has changed due to the successful therapy of tuberculosis with the help of the artificial pneumothorax.

During the gestation period, all the organs and tissues of the entire organism experience an increased load, as they are trying to satisfy both their own needs and that of the developing fetus. These morphological and functional changes do not lead to any pathological state in the mother if she is healthy and her course of pregnancy is normal. If the woman’s organism has been weakened by a chronic immunodeficiency due to poor environmental conditions or if she has a tuberculosis process in her organism, then functional changes and tissue dystrophies can develop in her nervous system which will lead to metabolic disorders. Changes in ergasia caused by pregnancy and connected with changes in higher nervous activity, as well as with endocrine reorganization, can influence the development and the course of the tubercular process.

Before penicillin was discovered, pregnancy usually led to the progression of the disease and in many cases even ended fatally. Nowadays due to the use of effective antituberculous medicines the attitude towards possible pregnancy of women who have active tuberculosis has considerably changed.

Tuberculosis in a pregnant woman usually starts in an acute form; at this stage infiltrative forms of the disease with necrogenic and bacterioexcretion prevail, often combined with exudative pleurisy, trachea, larynx and bronchi lesions.

Frequent consecutive pregnancies have a negative effect on the state of women who suffer from tuberculosis; they weaken the organism and can cause the recrudescence of the tuberculosis process. This is very typical of many families in poor Asian and African countries. More than half of all pregnant women suffering from an active form of tuberculosis experience a progressive iron deficiency anemia during the first three months of pregnancy and in the second trimester of pregnancy this can be observed in almost all patients. Malaria is also widespread in Asian and African countries that are situated to the south of Sahara and are the second reason for iron deficiency anemia.

According to modern views, one of the reasons for the recrudescence of the tubercular process during pregnancy is an irregular or non-systematic treatment of this illness or the absence of any treatment at all. The recrudescence of the process observed in those suffering from destructive pulmonary tuberculosis is caused by the severity of the illness itself when new conditions for the organism occur. In this case, pregnancy begins against the background of an advanced chronic immune deficiency. At the same time, due to the feto-placental complex operation, functional changes in the nervous, respiratory, cardiovascular and urinary systems, as well as hormonal changes, in the organism of a pregnant woman take place.

Moreover, the development of the fetal skeleton requires calcium which is absorbed not only via the blood of the mother, but also from the healed niduses of tuberculosis and as a result, the progression of a specific process can appear.

The reactivation of the tubercular process happens due to a decrease in the responsiveness of the organism and because of an increase in the activity of the reproductive hormones and the loosening of the connective tissues which are physiologically involved in pregnancy. The amount of plasma and extra vascular fluid increases. Due to these changes, a swelling and loosening in the inactive tubercular niduses with the mycobacteria of tuberculosis can appear. And loosening, in its turn, enables a lymphohematogenous spread of mycobacteria.

In addition to these, the delivery of a child leads to a speedy reorganization of all the functions of the organism; lactation and nursing in their turn are combined with an increased loss daily of nutritious matters and a large amount of protein and fats. In case of destructive pulmonary tuberculosis, due to the fact that the diaphragm descends (resulting in the abdominal decompression ceasing to have a therapeutic action of pneumoperitoneum) bronchogenic dissemination appears in the unaffected parts of the lungs.

A specific active process can be observed in women belonging to the high-risk group in connection with tuberculosis. The high-risk group combines women who have recently suffered from tuberculosis (less than one year after treatment), those who have just been operated on for a tuberculosis connected illness (less than one year), women with tuberculosis of different localizations younger than 20 years (for Asia and Africa) and those older than 35 years (for Europe and the USA), those with widespread forms of the tubercular process withstanding its stage, women who have had contact with people discharging bacteria or people suffering from tuberculosis but not discharging bacteria, and also those who have coexisting illnesses (diabetes, chronic nonspecific pulmonary illnesses, problems with kidneys, stomach and duodenum ulcer), and also women who use alcohol, narcotics, those who smoke and lead asocial ways of life. In these cases, the women must be properly examined during the gestation period, including X-rays.

Treatment of tuberculosis during pregnancy

All other conditions being equal, the timely detection of active tuberculosis during pregnancy allows doctors to provide a full course of treatment, allowing the woman to recover and give birth to a healthy child. Untreated active tuberculosis of the mother is much more dangerous for the fetus than anti-tuberculosis chemotherapy.

Special attention must be paid to healthy women who are in contact with bacillary patients. Quite often these women might undergo active tuberculosis for the first time during pregnancy or after the delivery itself.

In the pre-penicillin era the recrudescence of the tubercular process during pregnancy and after the delivery proceeded in an acute form with frank infiltrative changes, a necrogenic process, bloody expectoration and very often a generalization of the process. Nowadays, the clinical outlook for complications and the recrudescence of tuberculosis against the background of pregnancy is less gloomy. It more resembles the toxicosis of pregnancy or respiratory diseases.

While examining a patient, special attention must be paid to chest problems like moist or dry coughs, bloody expectoration, pain in the chest and shortness of breath. If the patient coughs with expectoration for 2 weeks then she must be examined for mycobacteria with the usage of a microscopic technique.

Another syndrome, which is also very important, is a complex of intoxication symptoms (weakness, hidrosis, anorexia, weight loss, long-lasting low grade fever and hyperirritability) which need to be detected to discover the reason for their development. While examining the anamnesis of a pregnant woman it is necessary to learn if she has ever suffered from tuberculosis before, if she has had any possible contacts with infected people, whether there are cases of tuberculosis or concomitant diseases in her family as all of these can be very useful for the verification of tuberculosis.

When active pulmonary tuberculosis is suspected an X-ray examination is necessary. When the chest is in frontal projection, the X-ray exposure of the fetus is 10 times lower than that of its mother (with compulsory use of a protective apron). Examination of the cough expectoration for the presence of tubercular mycobacteria is one of the easiest, most effective and informative diagnostic methods.

Chemotherapy, which destroys the tubercle bacillus that spread in the organism, plays a leading role in the variety of methods for tuberculosis treatment. By reducing the population of bacteria, chemotherapy supports the healing process, the dispersion of inflammatory changes, the closing of caverns, the encapsulation of the remaining loci as well as preventing the development of sclerosis. When the patient suffers from tuberculosis, the healing processes are very slow; the first stage of the recovery process of mycobacteria ceases and only after some months, in the case of a successful treatment of tuberculosis, does the healing process finish.

The necessary treatment of pregnant women who suffer from tuberculosis must start as soon as the diagnosis has been made. Chemotherapy implies taking antibacterial medicines (isoniaside, rifampicin, pyrazinamide, ethambutol, ethionamide and etc.) in different combinations. The choice of this or that combination depends on the stage of the disease as well as on any undesirable reactions to the medicines prescribed.

The treatment of tuberculosis (if there are indications) continues during the entire pregnancy and lactation period. In particular, patients with tuberculosis that has been diagnosed during the pregnancy are in need of treatment. When there is a systematic treatment, up to the moment of delivery and in the puerperal period, positive clinicoradiologic dynamics can be observed regarding the specific inflammation (stoppage of bacterioexcretion, closing of caverns, dispersion of loci, infiltration and exudate). Patients who reject treatment during the process of pregnancy suffer from an advancement of the illness.

Transplacental infection of the fetus with tuberculosis almost never occurs, but the baby can be infected from the mother in the puerperal period. There is also a possibility of contamination during delivery, but this is a rare occurrence.. God truly protects the innocent!

Permission to breast feed must be given by a joint resolution of an obstetrician, a pediatrician, and a specialist of tuberculosis taking into account the state of a woman and the form and the stage of the tubercular process. Overall precautionary measures must be taken (a nonbacterial mask of 5-6 layers covering the nose and the mouth, a kerchief covering the head and thoroughly washed hands).

A bacteriological study of the breast milk of women who suffer from tuberculosis shows that typical mycobacteria rarely vegetates (no more than 0.33%). Human milk has the ability to suppress the development of the mycobacteria of tuberculosis. This must be connected with the rich spectrum of ferments, immunoglobulins, cellular elements, macro-phages, the complement system, interferon and other factors of nonspecific protection which human milk contains.

The contraindications for nursing are as follows: tuberculosis of the lactiferous gland, an acute form of tuberculosis, active pulmonary tuberculosis with bacterioexcretion, active tuberculosis of any organs detected at the end of the pregnancy or after the delivery, and recrudescence of tuberculosis during the pregnancy. Children born to such mothers are immediately isolated after their birth and bottle fed, they are vaccinated and stay in the hospital for 6 weeks if possible (the minimum period for compulsory postvaccinal isolation).

Thus the tubercular process in the lungs, especially an active one, will have a negative influence on pregnancy and delivery. Babies born to such mothers belong to a high-risk group as far as the possibility of neonatal pathology and antenatal death of the fetus are regarded. Women with pulmonary tuberculosis must undergo regular consultations with both an obstetrician-gynecologist and a phthisiologist from the very early stages of their pregnancy. They must also receive special treatment until all the signs of active tuberculosis have been eliminated.

Smart structures can sense changes in their environment and respond accordingly. These adaptive structures can autonomously modify their shapes to perform the desired task regardless of the particular environmental disturbance.

“It’s difficult to bet on technology-you cannot always pick the winners, but it looks like smart materials would be the next step in engineering design,” says Craig A. Rogers, director of Virginia Tech’s Center for Intelligent Systems and Structures.

By using smart materials instead of adding mass, engineers can endow structures with built-in responses to a myriad of contingencies. In their various forms, these materials can perform as actuators, which can adapt to their environments by changing such characteristics as shape and stiffness, or as sensors, which provide actuators with information about structural and environmental changes.

Smart structures have numerous applications, among them the following:

SPACE STRUCTURES

Large space structures are subject to a variety of dynamic perturbations produced by the crew, the docking of other spacecraft, transient thermal states during the orbit, micrometeorities, and so on. The vibration amplitude of the perturbations has to be dampened in time to avoid further nonstability in the space structure.

In addition to that, the dampening of the flexible models is a necessary ingredient in achieving robust attitude control of the spacecraft.

AIRPLANES

Smart wings. Airplanes that have smart wings will control surfaces that can reshape themselves on the fly. Airplane wings will flex themselves like fish tails. With the help of smart structures, airfoil will be shaped and the aircraft’s lift will be improved. This improved lift will help to get a single-engine fighter off the deck of an aircraft carrier without a catapult.

Replacing current (and heavy) hydraulic control systems with light-weight, high-performance smart materials could increase aircraft payloads by as much as 30 percent and flight range by 50 percent.

Adaptive surfaces would replace stiff structures designed as a compromise among ideal wing shapes for various maneuvers. Eventually vertical tails, ailerons, and stiff structures could be eliminated.

HELICOPTERS

Active helicopter blades that adjust shape continuously to respond to vibration-engendering pressure changes in the air. These fluctuations knock the machinery out of alignment and cause a lot of down time. A helicopter’s maintenance schedule is approximately 15 percent of its time. In the helicopter project, piezoelectric patches on blade surfaces function both as sensors and as actuators, or as generators of counter-force.

Flutter suppression is a particularly important problem. Recent experiments in NASA wing tunnels with unoptimized smart structure designs have shown a 70 percent decrease in displacement and a 20 percent increase in blade speed by utilizing active vibration control concepts.

Active noise suspension for helicopter cabins promise greatly decreased acoustic noise/vibration intensities. This reduces stress upon crew members involved in increasingly longer duration missions.

SUBMARINES

Stealth submarines using smart skins. Smart materials technology may result in stealth submarines. Their acoustically hypersensitive smart skins would detect the pressure of an incoming sonar wave, and then automatically generate an equal but opposite counter-pressure to cancel out the ping. With nothing reflected back to enemy boat, the submarine would be invisible.

CARS

The automotive industry also is eager to incorporate intelligent materials technology. Some of the areas where smart material will be used are:

Smart car seats. Researchers are working on an industry-sponsored project to develop smart car seats that can identify primary occupants and adapt to their preferences for height, leg room, back support, and so forth.

Maintenance information. The technology exists to enable cars to tell owners how much air pressure tires have, when oil changes are needed, and other maintenance information.

Suspension and transmission. Smart materials that can change their viscosity (inherent thickness or resistance to flow) when exposed to electric or magnetic fields. This kind of smart material will lead to new kinds of auto suspensions and transmissions.

SKIS

A revolutionary piezo control module, developed by Active Control eXperts, Inc. (ACX), serves as “the brain inside the ski.”

The ACX “brain” is a small, thin, rectangular card containing piezoelectric smart materials and control circuits, which are embedded while the skis are being made. These materials detect unwanted vibrations in the skis and convert them into useful electrical energy. The control circuitry then uses the energy to smooth out the vibrations, putting the skis back on the snow. The result is a smoother ride, more responsive turning, and “solid stability.”

SOUND

Ultra-high-fidelity stereo speakers. Using piezoelectric actuators, such speakers can expand and contract in thousandths of a second in response to applied voltage. Speaker speakers in their homes and cars to achieve maximum musical effects. Their cars and houses will offer built-in surround-sound.

BUILDINGS

New bridge systems using fiber-optic lines and other sensors as strain indicators. Embedded in building materials, these devices would generate telltale optical or electrical signals when the system is stressed. Eventually, earthquake-resistant structures could be made using materials that would alter their stiffness in response to the ground’s motion, much as horseback riders flex their legs while riding.

Earthquake resistant structures. Smart structures will shake the building to cancel the effect of the earthquake.

Early warning. Smart structures will help determine possible structural damages due to the onset of structural degradation.