Interaction of Dye-surfactants and Dye-amino Acids

Interaction of Dye-surfactants and Dye-amino Acids Review of the literature shows that the study of interaction of dye-surfactants and dye-amino acids provide useful important information about physiological systems because of its widespread applications and relatively complex behaviour. These investigations are important from point of view of technology of dyeing processes as well as for chemical researches, such as biochemistry, analytical chemistry, and photosensitization. Most of the work on amino acids and biomolecules have been carried out in pure and mixed aqueous solutions but the investigation of spectroscopic, tensiometric and thermodynamic properties of amino acids in aqueous dye solution has rarely been done. On the other hand although studies have been made involving dye–surfactant interactions, yet this particular field of research is still important for improvised dyeing process in terms of theoretical, technological, environmental as well as economic point of view [1]. The dye-surfactant interaction has importa nce in many areas such as the spectral behaviour of dye in microheterogenous systems, dye-sensitized solar cells, and photocatalysis like photocatalytic water splitting. It is important to understand how surfactants and dyes interact in aqueous solutions to clarify the mechanisms of dyeing and other finishing procedures. Hence the investigation of interaction between surfactants / amino acid in aqueous dye solution was undertaken using different useful techniques. Mata et. al [2] investigated the physicochemical properties of pure cationic surfactants (quaternary salts) in aqueous solution by means of surface tension (at 303.15 K), conductance (at 293.15–333.15 K), dye solubilization and viscosity measurements. From the results it appeared that changes in the nature of the surfactant (such as changes in chain length, polar head group or counter ion) have a severe effect on the subsequent self-assembly in water. The increase in hydrophobic character of the surfactant decreases the CMC, induces sphere-to-rod transition at lower concentration and increases the solubilizing power of surfactant towards orange OT. Viscosity results indicated that the size of the micelles is relatively small at CMC and grows longer with increasing surfactant concentration. The plots of differential conductivity, (dk/dc)T,P, versus the total surfactant concentration enables us to determine the CMC values more precisely. The critical micelle concentration (cmc) and degree of ionization (ÃŽ ²) of cationic surfactants, dodecyldimethylethylammonium bromide (DDAB) and dodecyltrimethylammonium chloride (DTAC) in aqueous media were determined by Mehta et. al [3] from the conductivity measurements at different temperatures. The cmc behavior of DDAB and DTAC was analyzed in comparison with the results of DTAB in terms of effect of counter ion and increase in alkyl chain. It was observed that by changing the counter ion from chloride (DTAC) to bromide along with the increase in alkyl chain on polar head group (DDAB), the cmc shows a decrease. Thermodynamics of the system reveals that at lower temperatures, the micellization in case of DDAB was found to be entropy-driven, while at higher temperatures it was enthalpy driven. In DTAC system only entropic effect dominates over the entire temperature range. The aggregation properties of a cationic surfactant, DTAB, at different compositions in water-DMSO mixtures was studied by Và ©ronique Peyre et. al [4] using combination of techniques such as SANS, conductivity, and density measurements. Different complementary approaches were used for the interpretations of data. This multi-technique study explains the reason for the decrease in ionization degree, role of solvation in micellization and emphasizing the dissymmetric solvation of the chain by DMSO and the head by water. The study is interesting from the point of view that micellization process has been described by using combined analysis from molecular to macroscopic scale. Apparent and partial molar volumes of decyldimethylbenzylammonium chloride (C10DBACl) at (15, 25, and 35)  °C have been calculated from results of density measurements by A. G. Perez et. al [4]. The specific conductivities of the solutions have been determined at the same temperatures. The results served for the estimation of critical micelle concentration, cmc, ionization degree, (ÃŽ ²), and standard free energy of micellization, (à ¢Ã‹â€ Ã¢â‚¬  G), of the surfactant. J. J. Galan, J. R. RodrÄ ±guez [5] studied the molality dependence of specific conductivity of pentadecyl bromide, cetylpyridinium bromide and cetylpiridinium chloride in aqueous solutions in the temperature range of 30–45 à ¢-†¹C. The critical micelle concentration (cmc) and ionization degree of the micelles, ÃŽ ², were determined directly from the experimental data. Comparing our results for C16PBr and C16PCl water solutions, it can be observed that the substitution of the bromide anion by the more hydrophilic chloride leads to an increase in cmc by a factor of approximately 1.3. Chanchal Das and Bijan Das [6] have studied the micellization behavior of three cationic surfactants, viz., hexadecyl-, tetradecyl-, and dodecyltrimethylammonium bromide (CTAB, TTAB, and DTAB, respectively) in ethylene glycol (EG) (1) + water (2) mixed solvent media with varying mass fractions of EG (w1) by means of electrical conductivity and surface tension measurements. Temperature dependence of the critical micelle concentrations was also investigated to understand the micellar thermodynamics of these systems. From the study of the temperature dependence of the cmc of these surfactants in the EG (1) + water (2) mixture with w1 ) 0.30, they had demonstrated that the micellization was mainly governed by an enthalpy-entropy compensation effect. Data on the thermodynamics of adsorption demonstrate that the surface activity of these surfactant decreases with the addition of EG to water at a given temperature and that the adsorption of surfactant at the air/mixture interface takes plac e spontaneously. The micellisation behaviour of cetyltrimethylammonium bromide (CTABr) in different mass fraction (17–47) of ethylene glycol (EG), dimethylsulfoxide (DMSO), and dimethylformamide (DMF)–water mixed solvents, was studied by Olaseni et. al [7] using electrical conductivity measurement at different temperatures (293.1–313.1 K). The results of the thermodynamic analysis showed that addition of organic solvents, which are principally located in the bulk phase made the micellisation process less spontaneous. The London-dispersion interaction represented the major attraction force for micellisation and micellisation proceeded via an exothermic process. Sar Santosh K and Rathod Nutan [8] evaluated cmc, ÃŽ ± value and the thermodynamic parameters of the process of micellization for alkyl (C12, C14, and C16) trimethylammonium bromide systems in presence of water-dimethylformamide (5-20 % v/v) binary mixtures over a temperature range of 298-318 K. It was observed that both the cmc and ÃŽ ± value were dependent upon the (v/v %) of solvent and temperature and the micellization tendency of cationic surfactant decreases in the presence of solvents. It was also observed that the micellization is favored in general by entropy and enthalpy at higher temperatures, whereas it is favored mainly by entropy at low temperatures. A. Ali et. al [9] have studied the thermodynamic properties of sodium dodecyl sulphate in micellar solution of L-serine and L-threonine by fluorescence spectroscopy and dynamic light scattering techniques. They observed a decrease in cmc of SDS in Thr solutions as compared to that in Ser. The determined values of à ¢Ã‹â€ Ã¢â‚¬  G become increasingly negative in the order: water > Ser >Thr, suggesting that the formation of micelles is more favorable in presence of amino acids than in pure water. The aggregation behavior of SDS was explained in terms of structural changes in mixed solutions. On the basis of dynamic light scattering it was suggested that the size of SDS micelles was influenced by the presence of amino acids. F. Jalali and A. Gerandaneh [10] computed the critical micelle concentration (cmc) of cetyltrimethylammonium bromide (CTAB) conductometrically in binary mixtures of water + cosolvent at various temperatures and in the presence of potassium bromide (2.0 – 14 X10-3 M). Dioxane and acetonitrile were used as cosolvents added to water. Addition of organic solvents to water increased the cmc value of CTAB, but the presence of KBr lowered cmc. Thermodynamic parameters of micellization, were evaluated for each solution according to the pseudo-phase model, and the changes observed in these parameters were related to the presence of KBr and cosolvents in aqueous solution. The conductivity of (cosolvent C water) in the presence of increasing concentration of 1-hexadecylpyridinium bromide was measured at various temperatures by F. Jalali et al. [11]. Acetonitrile, dimethylformamide, dimethylsulfoxide, dioxane and ethylene glycol were used as cosolvents. From the conductivity data, the critical micelle concentration c.m.c., and the effective degree of counter ion dissociation ÃŽ ±, were obtained at various temperatures. In all the cases studied, a linear relationship between ([c.m.c] / mol . dm-3) and the mass fraction of cosolvent in solvent mixtures was observed. The thermodynamic properties à ¢Ã‹â€ Ã¢â‚¬  Hand à ¢Ã‹â€ Ã¢â‚¬  Swere evaluated from the temperature dependence of the equilibrium constants for micellization of the surfactant. While the micellization process in pure water is both enthalpy and entropy stabilized, it becomes entropy destabilized in all solvent mixtures used; the values of à ¢Ã‹â€ Ã¢â‚¬  S being more negative with increase i n the cosolvent content of the solvent mixtures. The resulting à ¢Ã‹â€ Ã¢â‚¬  H against Tà ¢Ã‹â€ Ã¢â‚¬  S plot showed a fairly good linear correlation, indicating the existence of an enthalpy–entropy compensation in the micellization process. The effect of the simultaneous presence of an electrolyte (NaBr) and nonelectrolyte species (DMSO and AN) in aqueous solution on the micellization of HDPB was studied by F. Jalali and A. Shaeghi Rad [12]. They concluded that the presence of NaBr favors the micellization of HDPB mainly due to a decrease in repulsions between micelle head groups. Adding a cosolvent, such as DMSO or AN, to water inhibits the formation of micelles because of the increase in hydrophobic character of the mixed solvent, which increases the attraction of surfactant monomers toward the solvent.

Dust Bowl of the 1930s

The Dust Bowl of the 1930’s had such an antagonistic effect on the United States economy that was already plummeting. The Dust Bowl affected the U. S economy in just about every way possible ranging from agriculture to finances including government expenses to population changes. This phenomena can be considered as one of the worst natural disasters that has affected the United States. The â€Å"Dust Bowl† was the name given to the Great Plains region that was greatly affected by drought in the 1930’s during the Great Depression. The major contribution that led to the Dust Bowl was overproduction of crops however there were some natural causes. Much of the soil there had been damaged by wind and rain. The soil in this area was subjected to water and wind damage because the protective cover of vegetation was impaired through poor farming and the grazing of too many animals† (World Book Encyclopedia). The overproduction was due in part to the fact that the co untry was in the midst of World War I. â€Å"During World War I international demand for food crops like wheat and corn soared. Because of this farmers planted more crops and took out loans to buy land and equipment. But after the war demand for farm products declined and crop prices fell by fifty percent† (Danzer 651-652). In and effort to make up for the falling prices, farmers tried to plant even more crops, but this only caused lower prices. As a result of these poor land management practices and lack of precipitation the land became arid. There was little grass and few trees to hold the soil down. When the wind storms hit, dust was blown all over, making it virtually impossible for farming. When farming in the Great Plains was no longer a way of making a living many of the inhabitants left the land behind and moved west to California in search of work. â€Å"Plagued by dust storms and evictions, thousands of farmers and sharecroppers left their land behind. They packed up their families and their few belongings and headed west, following route 66 to California† (Danzer 652). The term Okies was coined to describe the migrants from Oklahoma but was later used to describe all migrants. â€Å"By the end of the 1930’s, the population of California had grown by more than one million† (Danzer 652). Those who remained in the drought regions were forced to endure severe dust storms and their health effects, diminished incomes, animal infestations, and the physical and emotional stress over their uncertain futures was unbearable (National Drought Mitigation Center, online). As the Great Depression wore on, the government took steps to intervene and try to save the nation. Led by the effort within the U. S. Department of Agriculture, newly created agencies like the Soil Conservation Service (SCS), the Resettlement Administration (RA), and the Farm Security Administration (FSA) were the loudest to publicize and deplore the Dust Bowl wracking America's heartland (Cunfer, online). Also led by the President Herbert Hoover and the United States Congress, the Federal Home Loan Bank Act was passed in 1933. This act lowered mortgage rates for homeowners and allowed farmers to refinance their farm loans and avoid foreclosure. Newly elected President Franklin Delano Roosevelt succeeded Hoover in 1932 during the ongoing Depression. FDR proposed many acts to try and resolve the national issues in his program titled the â€Å"New Deal† . One of his most recognized acts that directly assisted farmers was known as the Agricultural Adjustment Act. â€Å"This act sought to raise crop prices by lowering production, which the government achieved by paying farmers to not grow† (Danzer 667). A second program that was passed was the Civilian Conservation Corps. This program put young men to work to perform public jobs including planting trees and helping soil erosion. The United States government spent unprecedented amounts of money to recover from the Great Depression and the Dust Bowl. â€Å"The magnitude of the droughts of the 1930s, combined with the Great Depression, led to unprecedented government relief efforts. Congressional actions in 1934 alone accounted for relief expenditures of $525 million, the total cost would be impossible to determine† (National Drought Mitigation Center, online). Despite all the negative effects of the Dust Bowl and the Great Depression there were a few positives. For one thing all the government sponsored programs provided jobs and a source of income for those who were unemployed. Also the Roosevelt era marked the beginning of large-scale aid. This also ushered in some of the first long-term, proactive programs to reduce future vulnerability to drought (National Drought Mitigation Center, online). The Dust Bowl was one of the worst natural disasters that has affected the United States. This disaster along with the Great Depression had negative influences on agriculture, state populations, and finances including individual families and the government. However, in the face of all this commotion a few positive results occurred. People found jobs and a source of income and the government was able to bring the nation out of turmoil. Work Cited Danzer, Gerald A, et al. â€Å"The Depression. † The Americans. Boston: McDougal Littell, 2000. 642-676. Print. â€Å"Dust Bowl. † The World Book Encyclopedia. Vol. 4. N. p. : Field Enterprises, 1958. Print. 18 vols. Drought in the Dust Bowl Years. National Drought Mitigation Center, 2006. Web. 14 Nov. 2009. . Cunfer, Geoff. EH. Net Encyclopedia: The Dust Bowl. N. p. , n. d. Web. 14 Nov. 2009. .

In-Depth Psychoanalysis Essay

The formation and maintenance of the psychoanalysis frame is important for the function of setting up an ideal emotional relationship with a patient. It is the ability to know how to help the patient by deducing the emotional projections and barriers that are present within the patient’s psyche (Bishop, 1989). The concept of psychic reality embraces the image of the external world, which accommodates the internal world in an individual that is composed of masculine and feminine energies. It is important for psychoanalysts to comprehend this existing relationship between the external and internal world so that the patient will not be confused in understanding his or her situation (Bishop, 1989). In psychoanalysis, both analyst and patient are expected to merge the inner and outer subjectivity of the patient. The analyst’s main role is to figure out what is the scope of that subjectivity and form a suitable analysis of it that will be able to help both of them to find a solution. The analyst should strive to become a part of the patient’s illness in order to arrive at a solution. This is called Transference which is a central element to psychoanalysis (Bishop, 1989). The door to the past is opened through transference as it seeks to make sense of the present. Objectivity has no place in psychoanalysis because the process is derived from the complexities found within the patient’s psyche. An analyst must be able to honor the patient’s projections of reality for it is there that the solution may be brought to light (Bishop, 1989). A conceptual frame exists in the process of psychoanalysis in which the mode of transference is indicative of the projections offered by both the patient and the analyst. It is imperative that an analyst maintains the frame by respecting the patient’s time as it is giving the patient an opportunity to handle his or her own problems (Bishop, 1989). While both the analyst and the patient remain independent, mental interpenetration should be experienced by both parties through the combined efforts of projective identification. It is a process that permits bonding with the patient, alluding to a psychic intercourse. In psychotherapy, the psychotherapist is expected to psychically bond with the patient as a marital partner that nurses the wounded child found within the patient (Bishop, 1989). Psychological elements within the frame emphasizes on three things: Neutrality, anonymity and avoidance of extra-analytic contact. The first element, neutrality, considers a behavior in which the analyst withholds external manifestations of judgment to keep things professional and the psychoanalytic process unaffected. The second element deals with anonymity, which exhibits separation of an analyst’s personal life from the profession. It is obscuring personal attributes and judgment from a patient, except if it is considered beneficial to the situation at hand. The last element, avoidance of extra-analytic contact, upholds the professionalism of the psychoanalyst by deciding to evade places where patients would most likely be. This will set limitations between analyst and patient by not encouraging further contact between the two parties aside from those established within the bounds of the psychoanalysis sessions (Bishop, 1989). Along with these elements, silence contributes a great deal toward intervention in psycho-analytic treatment. It promotes an attitude toward to a gestational state where the individual could combine thoughts and feelings. The space in the room should be filled with the patient’s mind and not the therapists’ knowledge. Silence allows the patient to center on what is inside rather than what is outside. An analyst should take care not to interfere with this process as language may affect its course (Bishop, 1989). Another thing an analyst should keep in mind is interpreting the silence by giving importance to the transference process, exposing the unconscious mind. The purpose of unraveling such consciousness is to project the instinctual or the here and now. Transference brings rise to object relations connected with the patient’s anxieties toward unconsciousness (Bishop, 1989). For an analyst to be more attuned toward the needs of the patient, derivatives must be presented in order to clarify what was obtained from the transference. It is keeping the exchange route open and flowing. The frame of psychoanalysis should be preserved in such a way that it allows room for both the patient and the analyst to bond together by figuring out the source of the psychological discomfort. It is establishing a stable connection between the patient and the analyst (Bishop, 1989). 2. Discuss Bion’s Model as it relates to psychological development and psychotherapeutic process. What correlates do you find in the work of Freud and Kohut? Initially, Bion’s interpretations of the subconscious mind gravitate toward the idea that thoughts precede thinking. He believes that people have existing preconceptions about the environment and their realizations. When these two factors meet, it serves as a basis for thinking (Bishop, 1989). Bion postulates that each person possesses an inclination to be psychotic (PPP), though it is very much different from being in a state of psychosis. For Bion, it involves a set of process in which sufficient trauma activates the reversion of PPP, enabling one to experience such a state. It is fueled by the death instinct that affects the instinctual drive to kill and the ability to think and feel (Bishop, 1989). Feelings and thoughts are processed by the patient as a separate entity from him or her; therefore, the psychotic part emerges as a detached state that breaks the linkages between thoughts and feelings. As a result, destructive impulses, intolerant frustrations, hatred and irritability occur within the patient, rendering narcissistic love into sadism (Bishop, 1989). The patient experiencing this kind of state lives in a state of persecution through the creation of bizarre objects or hallucinations. This part of the personality relies on removing any negative thought-process through projective identification. Most often, projective identification refers to the pathological element of execution but under normal circumstances, it is a mode of interpersonal communications that permits the patient to express his or her feelings for the analyst to make sense of them. Such frightening expressions of the patient create a digestible container in the analyst who accepts the projected reality (Bishop, 1989). The analyst then interjects such expressions or beta elements surrounding the projection. The analyst needs to acknowledge how frightening the projection is and respond to it appropriately. Â  This process is known as alpha function, which simply associates itself from the feeding ritual of birds. The parent bird feeds the baby by taking the worm and digesting it through the creation of bite-size pieces. When the digestion is achieved, the parent bird regurgitates it in the mouth of the baby bird in order to help the baby bird digest the food. The human counterpart features the analyst as the parent bird and the patient as the baby bird. The patient projects a reality to the analyst, which in turn is emotionally digested by the analyst and offered back to the patient. The analyst needs to regress in order to process projective identification so that it coincides with what the patient has given (Bishop, 1989). If the beta element returned by the therapist is unstable, the patient will assume that the therapist is of no help as he or she could not comprehend the situation. This leads the patient to feel misunderstood and alone. From this, the patient starts to project a more violent attitude toward the analyst. The outcome may lead to psychosis if the patient is unable to find another container on which to project the beta elements. The analyst must be able to reframe the beta elements in order to provide the big picture to the patient (Bishop, 1989). With regard to Kohut and Freud, both place special emphasis on narcissism. Kohut identifies narcissism as a way of rejection by discarding oneself into another’s experience through empathy. It is the primary therapeutic tool that does not connote affect or emotional attitude. The affect is only experienced once the analyst finally comprehends the patient’s circumstance (Curtis, 2008). While Freud may have discussed how an individual relates to his or her being as an object and creates conflict within if disappointments occur, separating it from the line of development, Kohut believes that the narcissistic line is a long-term process. People take what they can from their environment all throughout their lives, which is what fuels narcissism (Curtis, 2008). The transference in Kohut’s explanation takes place in the selfobject relationship which provides a mirroring positive response to the patient that is in dire need of it. It is the proliferation of affirmation, appreciativeness, and fulfillment of purpose, which supports narcissism in its most positive sense. The function of this is to supply the emotional deficit that is lacking in the environment of the patient (Curtis, 2008). One of the major changes that have occurred from traditional psychoanalysis is the introduction of selfobject as a counterpart of the projective identification of Klein/Freud. It sets up primary emotional connections that aid in psychological development. The process is not concerned with the outside notions of the self but of the inner projections that manifests itself through deficits (Curtis, 2008). Another modification concerns the predisposition of the analyst of the past to take things from an objective perspective to a subjective experience. This view intercepts the existing relationship of the analyst-patient into one unit which also encourages counter-transference on the part of the analyst (Curtis, 2008). Psychotherapy involves the examination of a patient’s long history and the fragments of mal-attunments that affects his or her sense of self. The role of the analyst is to assist the patient in re-establishing the nuclear self and assesses realistically the positive side of the patient’s psyche. This is the only way for the patient to willingly internalize the deficits through optimal failures. Failure is essential to the growth of an individual since it helps develop perseverance and maintain a healthy ego. Psychotherapy helps in the process of arriving at the selfobject needs of patient through the awareness of the existing deficits and responding empathically to it (Curtis 2008). References: Bishop, A. (1989). Classical psychoanalytic technique. In R. Langs (Ed.). New York: Guilford Press. Curtis, R.C. (2008). Desire, Self, Mind, and the Psychotherapies: Unifying Psychological Science and Psychoanalysis (The New Imago). (1st ed.). New York: Jason Aronson.

Early Explorers of Africa

Even in the 18th century, much of the interior of Africa was unfamiliar to Europeans. Most of their time in Africa was limited to trade along the coast, first in gold, ivory, spices, and later slaves. In 1788 Joseph Banks, the botanist whod sailed across the Pacific Ocean with Cook, went as far as to found the African Association to promote the exploration of the interior of the continent. Ibn Battuta Ibn Battuta (1304-1377) traveled over 100,000 kilometers from his home in Morocco. According to the book he dictated, he traveled as far as Beijing and the Volga River; scholars say its unlikely he traveled everywhere he claims to have. James Bruce James Bruce (1730-94) was a Scottish explorer who set off from Cairo in 1768 to find the source of the River Nile. He arrived at Lake Tana in 1770, confirming that this lake was the origin of the Blue Nile, one of the tributaries of the Nile. Mungo Park Mungo Park (1771-1806) was hired by the African Association in 1795 to explore the River Niger. When the Scotsman returned to Britain having reached the Niger, he was disappointed by the lack of public recognition of his achievement and that he was not acknowledged as a great explorer. In 1805 he set out to follow the Niger to its source. His canoe was ambushed by tribesmen at the Bussa Falls and he drowned. Renà ©-Auguste Caillià © Renà ©-Auguste Caillià © (1799-1838), a Frenchman, was the first European to visit Timbuktu and survive to tell the tale. Hed disguised himself as an Arab to make the trip. Imagine his disappointment when he discovered that the city wasnt made of gold, as legend said, but of mud. His journey started in West Africa in March 1827, headed towards Timbuktu where he stayed for two weeks. He then crossed the Sahara (the first European to do so) in a caravan of 1,200 animals, then the Atlas Mountains to reach Tangier in 1828, from where he sailed home to France. Heinrich Barth Heinrich Barth (1821-1865) was a German working for the British government. His first expedition (1844-1845)was from Rabat (Morocco) across the coast of North Africa to Alexandria (Egypt). His second expedition (1850-1855) took him from Tripoli (Tunisia) across the Sahara to Lake Chad, the River Benue, and Timbuktu, and back across the Sahara again. Samuel Baker Samuel Baker (1821-1893) was the first European to see the Murchison Falls and Lake Albert, in 1864. He was actually hunting for the source of the Nile. Richard Burton Richard Burton (1821-1890) was not only a great explorer but also a great scholar (he produced the first unabridged translation of The Thousand Nights and a Night). His most famous exploit is probably his dressing as an Arab and visiting the holy city of Mecca (in 1853) which non-Muslims are forbidden to enter. In 1857 he and Speke set off from the east coast of Africa (Tanzania) to find the source of the Nile. At Lake Tanganyika Burton fell seriously ill, leaving Speke to travel on alone. John Hanning Speke John Hanning Speke (1827-1864) spent 10 years with the Indian Army before starting his travels with Burton in Africa. Speke discovered Lake Victoria in August 1858 which he initially believed to be the source of the Nile. Burton didnt believe him and in 1860 Speke set out again, this time with James Grant. In July 1862 he found the source of the Nile, the Ripon Falls north of Lake Victoria. David Livingstone David Livingstone (1813-1873) arrived in Southern Africa as a missionary with the aim of improving the life of Africans through European knowledge and trade. A qualified doctor and minister, he had worked in a cotton mill near Glasgow, Scotland, as a boy. Between 1853 and 1856 he crossed Africa from west to east, from Luanda (in Angola) to Quelimane (in Mozambique), following the Zambezi River to the sea. Between 1858 and 1864 he explored the Shire and Ruvuma river valleys and Lake Nyasa (Lake Malawi). In 1865 he set off to find the source of the River Nile. Henry Morton Stanley Henry Morton Stanley (1841-1904) was a journalist sent by the New York Herald to find Livingstone who had been presumed dead for four years as no-one in Europe had heard from him. Stanley found him at Uiji on the edge of Lake Tanganyika in Central Africa on 13 November 1871. Stanleys words Dr. Livingstone, I presume? have gone down in the history as one of the greatest understatements ever. Dr. Livingstone is said to have replied, You have brought me new life. Livingstone had missed the Franco-Prussian War, the opening of the Suez Canal, and the inauguration of the transatlantic telegraph. Livingstone refused to return to Europe with Stanley and continued on his journey to find the source of the Nile. He died in May 1873 in the swamps around Lake Bangweulu. His heart and viscera were buried, then his body was carried to Zanzibar, from where it was shipped to Britain. He was buried at Westminster Abbey in London. Unlike Livingstone, Stanley was motivated by fame and fortune. He traveled in large, well-armed expeditions -- he had 200 porters on his expedition to find Livingstone, who often traveled with only a few bearers. Stanleys second expedition set off from Zanzibar towards Lake Victoria (which he sailed around in his boat, the Lady Alice), then headed into Central Africa towards Nyangwe and the Congo (Zaire) River, which he followed for some 3,220 kilometers from its tributaries to the sea, reaching Boma in August 1877. He then set off back into Central Africa to find Emin Pasha, a German explorer believed to be in danger from warring cannibals. The German explorer, philosopher, and journalist Carl Peters (1856-1918) played a significant role in the creation of Deutsch-Ostafrika (German East Africa) A leading figure in the Scramble for Africa Peters was ultimately vilified for his cruelty to Africans and removed from office. He was, however, considered a hero by the German emperor Wilhelm II and Adolf Hitler. Mary Kingsley's Mary Kingsleys (1862-1900) father spent most of his life accompanying noblemen around the world, keeping diaries and notes which he hoped to publish. Educated at home, she learned the rudiments of natural history from him and his library. He employed a tutor to teach his daughter German so she could help him translate scientific papers. His comparative study of sacrificial rites around the world was his major passion and it was Marys desire to complete this which took her to West Africa after her parents deaths in 1892 (within six weeks of each other). Her two journeys werent remarkable for their geological exploration, but were remarkable for being undertaken, alone, by a sheltered, middle-class, Victorian spinster in her thirties without any knowledge of African languages or French, or much money (she arrived in West Africa with only  £300). Kingsley did collect specimens for science, including a new fish which was named after her. She died nursing prisoners of war in Simons Town (Cape Town) during the Anglo-Boer War. The article is a revised and expanded version of that first published on 25 June 2001.