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Displaying 76 - 100 of 303 items.

"The Cell-Theory" (1853), by Thomas Henry Huxley

The Cell-Theory was written by Thomas Henry Huxley in Britain and published in 1853 by The British and Foreign Medico-Chirurgical Review. The twenty-two page article reviews twelve works on cell theory, including those in Germany by Caspar Friedrich Wolff in the eighteenth century and by Karl Ernst von Baer in the nineteenth century. Huxley spends much of The Cell-Theory on a cell theory proposed in the late 1830s by Matthias Schleiden and Theodor Schwann in Germany.

Format: Articles

Subject: Publications

Ignaz Philipp Semmelweis (1818-1865)

Ignaz Philipp Semmelweis demonstrated that the use of disinfectants could reduce the occurrence of puerperal fever in patients in nineteenth century Austria. Puerperal fever is a bacterial infection that can occur in the uterine tract of women after giving birth or undergoing an abortion. Semmelweis determined that puerperal fever is contagious and argued that the unhygienic practices of physicians, like examining patients after performing autopsies, caused the spread of puerperal fever.

Format: Articles

Subject: People

Dinosaur Egg Parataxonomy

Dinosaur egg parataxonomy is a classification system that organizes dinosaur eggs by descriptive features such as shape, size, and shell thickness. Though egg parataxonomy originated in the nineteenth century, Zi-Kui Zhao from Beijing, China, developed a modern parataxonomic system in the late twentieth century. Zhao's system, published in 1975, enabled scientists to organize egg specimens according to observable features, and to communicate their findings.

Format: Articles

Subject: Theories

The Hedgehog Signaling Pathway in Vertebrates 

The hedgehog signaling pathway is a mechanism that regulates cell growth and differentiation during embryonic development, called embryogenesis, in animals. The hedgehog signaling pathway works both between cells and within individual cells.

Format: Articles

Subject: Theories

Johann Friedrich Meckel, the Younger (1781-1833)

Johann Friedrich Meckel studied abnormal animal and human anatomy in nineteenth century Germany in an attempt to explain embryological development. During Meckel's lifetime he catalogued embryonic malformations in multiple treatises. Meckel's focus on malformations led him to develop concepts like primary and secondary malformations, atavism, and recapitulation- all of which influenced the fields of medicine and embryology during the nineteenth and twentieth centuries.

Format: Articles

Subject: People

"Derivation of Pluripotent Stem Cells from Cultured Human Primordial Germ Cells" (1998), by John Gearhart et al.

In November 1998, two independent reports were published concerning the first isolation of pluripotent human stem cells, one of which was "Derivation of Pluripotent Stem Cells from Cultured Human Primordial Germ Cells." This paper, authored by John D. Gearhart and his research team - Michael J Shamblott, Joyce Axelman, Shunping Wang, Elizabeith M. Bugg, John W. Littlefield, Peter J. Donovan, Paul D. Blumenthal, and George R. Huggins - was published in Proceedings of the National Academy of Science soon after James A.

Format: Articles

Subject: Publications

Ectoderm

Ectoderm is one of three germ layers--groups of cells that coalesce early during the embryonic life of all animals except maybe sponges, and from which organs and tissues form. As an embryo develops, a single fertilized cell progresses through multiple rounds of cell division. Eventually, the clump of cells goes through a stage called gastrulation, during which the embryo reorganizes itself into the three germ layers: endoderm, ectoderm, and mesoderm. After gastrulation, the embryo goes through a process called neurulation, which starts the development of nervous system.

Format: Articles

Subject: Processes

Max Ludwig Henning Delbruck (1906–1981)

Max Ludwig Henning Delbrick applied his knowledge of theoretical physics to biological systems such as bacterial viruses called bacteriophages, or phages, and gene replication during the twentieth century in Germany and the US. Delbrück demonstrated that bacteria undergo random genetic mutations to resist phage infections. Those findings linked bacterial genetics to the genetics of higher organisms. In the mid-twentieth century, Delbrück helped start the Phage Group and Phage Course in the US, which further organized phage research.

Format: Articles

Subject: People

John Chassar Moir (1900–1977)

John Chassar Moir lived in Scotland during the twentieth century and helped develop techniques to improve the health of pregnant women. Moir helped to discover compounds that doctors could administer to women after childbirth to prevent life-threatening blood loss. Those compounds included the ergot alkaloid called ergometrine, also called ergonovine, and d-lysergic acid beta-propanolamide. Moir tested ergometrine in postpartum patients and documented that it helped prevent or manage postpartum hemorrhage in women.

Format: Articles

Subject: People, Reproduction, Disorders

Meselson, Stahl, and the Replication of DNA: A History of "The Most Beautiful Experiment in Biology" (2001), by Frederic Lawrence Holmes

In 2001, Yale University Press published Frederic Lawrence Holmes' book, Meselson, Stahl, and the Replication of DNA: A History of "The Most Beautiful Experiment in Biology" (Replication of DNA), which chronicles the 1950s debate about how DNA replicates. That experiment verified that DNA replicates semi-conservatively as originally proposed by Watson and Crick. Rather than focusing solely on experiments and findings, Holmes's book presents the investigative processes of scientists studying DNA replication.

Format: Articles

Subject: Publications

Matthew Stanley Meselson (1930– )

Matthew Stanley Meselson conducted DNA and RNA research in the US during the twentieth and twenty-first centuries. He also influenced US policy regarding the use of chemical and biological weapons. Meselson and his colleague Franklin Stahl demonstrated that DNA replication is semi-conservative. Semi-conservative replication means that every newly replicated DNA double helix, which consists of two individual DNA strands wound together, contains one strand that was conserved from a parent double helix and that served as a template for the other strand.

Format: Articles

Subject: People

Sex Determination in Humans

In humans, sex determination is the process that determines the biological sex of an offspring and, as a result, the sexual characteristics that they will develop. Humans typically develop as either male or female, depending on the combination of sex chromosomes that they inherit from their parents. The human sex chromosomes, called X and Y, are structures in human cells made up of tightly bound deoxyribonucleic acid, or DNA, and proteins.

In humans, sex determination is the process that determines the biological sex of an offspring and, as a result, the sexual characteristics that they will develop. Humans typically develop as either male or female, depending on the combination of sex chromosomes that they inherit from their parents. The human sex chromosomes, called X and Y, are structures in human cells made up of tightly bound deoxyribonucleic acid, or DNA, and proteins.

Format: Articles

Subject: Processes, Processes

Thesis: Reproduction in Science Fiction

Science fiction works can reflect the relationship between science and society by telling stories that are set in the future of ethical implications or social consequences of scientific advancements. This thesis investigates how the concept of reproduction is depicted in popular science fiction works.

Format: Essays and Theses

Subject: Publications, Reproduction

Virginia Apgar (1909-1974)

Virginia Apgar worked as an obstetrical anesthesiologist, administering drugs that reduce women’s pain during childbirth, in the US in the mid-twentieth century. In 1953, Apgar created a scoring system using five easily assessable measurements, including heart rate and breathing rate, to evaluate whether or not infants would benefit from medical attention immediately after birth. Apgar’s system showed that infants who were previously set aside as too sick to survive, despite low Apgar scores, could recover with immediate medical attention.

Format: Articles

Subject: People, Reproduction

Thesis: Leo Kanner and the Psychobiology of Autism

This thesis illustrates that Kanner held an explicitly descriptive frame of reference toward his eleven child patients, their parents, and autism. Adolf Meyer, his mentor at Johns Hopkins, trained him to make detailed life-charts under a clinical framework called psychobiology. By understanding that Kanner was a psychobiologist by training, I revisit the original definition of autism as a category of mental disorder and restate its terms.

Format: Essays and Theses

Subject: People, Disorders

Dissertation: Degeneration in Miniature: History of Cell Death and Aging Research in the Twentieth Century

Once perceived as an unimportant occurrence in living organisms, cell degeneration was reconfigured as an important biological phenomenon in development, aging, health, and diseases in the twentieth century. This dissertation tells a twentieth-century history of scientific investigations on cell degeneration, including cell death and aging.

Format: Essays and Theses

Subject: Processes, Organisms

Thesis: A Contextual Understanding of the Definition of Science in South Korea

Despite the minor differences in the inclusiveness of the word, there is a general assumption among the scientific community that the 'pursuit of knowledge' is the most fundamental element in defining the word 'science.' However, a closer examination of how science is being conducted in modern-day South Korea reveals a value system starkly different from the value of knowledge. By analyzing the political discourse of the South Korean policymakers, mass media, and government documents, this study examines the definition of science in South Korea.

Format: Essays and Theses

Subject: Places

Thesis: The Hwang Woo-Suk Scandal and the Development of Bioethics in South Korea

In 2004, the South Korean geneticist Woo-Suk Hwang published what was widely regarded as the most important research finding in biotechnology that year. In the prestigious American journal Science, he claimed that he had succeeded in cloning a human blastocyst, which is an embryo in its early developmental stages (Hwang et al. 2004). A year later, in a second Science article, he made the earth-shattering announcement that he had derived eleven embryonic stem cell lines using his cloning technique (Hwang et al. 2005). The international scientific community was stunned.

Format: Essays and Theses

Subject: Ethics, People

Thesis: A History of Cellular Senescence and Its Relation to Stem Cells in the Twentieth and Twenty-First Centuries

This study aims to provide information to answer the following question: While some scientists claim they can indefinitely culture a stem cell line in vitro, what are the consequences of those culturing practices? An analysis of a cluster of articles from the Embryo Project Encyclopedia provides information to suggest possible solutions to some potential problems in cell culturing, recognition of benefits for existing or historical culturing practices, and identification of gaps in scientific knowledge that warrant further research.

Format: Essays and Theses

Subject: Processes, Publications

Dissertation: Fetal Risk, Federal Response: How Fetal Alcohol Syndrome Influenced the Adoption of Alcohol Health Warning Labels

In the fifteen years between the discovery of fetal alcohol syndrome, or FAS, in 1973 and the passage of alcohol beverage warning labels in 1988, FAS transformed from a medical diagnosis between practitioner and pregnant women to a broader societal risk imbued with political and cultural meaning. In this dissertation, I examine how scientific, social, moral, and political narratives dynamically interacted to construct the risk of drinking during pregnancy and the public health response of health warning labels on alcohol.

Format: Essays and Theses

Subject: Disorders, Reproduction, Legal

Thesis: The Genesis of Premenstrual Syndrome (PMS)

This is a project about medicine and the history of a condition called premenstrual syndrome (PMS), its “discovery” and conceptual development at both scientific and socio-cultural levels. Since it was first mentioned in medical literature, PMS has been explored empirically as a medical condition and conceptually as a non-somatic cultural phenomenon. Many attempts have been made to produce scientific, empirical evidence to bolster the theory of PMS as a biological disease.

Format: Essays and Theses

Subject: Reproduction

Lynn Petra Alexander Sagan Margulis (1938-2011)

Lynn Petra Alexander Sagan Margulis was an American biologist, whose work in the mid-twentieth century focused on cells living together in a mutually advantageous relationship, studied cells and mitochondria in the US during the second half of the twentieth century. She developed a theory for the origin of eukaryotic cells, that proposed two kinds of structures found in eukaryotic cells mitochondria in animals, and plastids in plantsÑwere once free-living bacteria that lived harmoniously and in close proximity to larger cells, a scenario called symbiosis.

Format: Articles

Subject: People, Theories

Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Gene

The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene was identified in 1989 by geneticist Lap-Chee Tsui and his research team as the gene associated with cystic fibrosis (CF). Tsui's research pinpointed the gene, some mutations to which cause CF, and it revealed the underlying disease mechanism. The CFTR gene encodes a protein in the cell membrane in epithelial tissues and affects multiple organ systems in the human body. Mutations in the CFTR gene cause dysfunctional regulation of cell electrolytes and water content.

Format: Articles

Subject: Disorders, Reproduction

Jeffrey Weinzweig's Experiments on In Utero Cleft Palate Repair in Goats (1999-2002)

Jeffrey Weinzweig and his team, in the US at the turn of the twenty-first century, performed a series of experiments on fetal goats to study the feasibility of repairing cleft palates on organisms still in the womb. Weinzweig , a plastic surgeon who specialized in cleft palate repair, and his team developed a method to cause cleft palates in fetal goats that are similar to clefts that occur in human fetuses. Using their goat congenital model, the team developed a method to repair a congenital cleft palate in utero, or in the womb.

Format: Articles

Subject: Experiments, Disorders

Craig C. Mello (1960- )

Craig C. Mello is an American developmental biologist and Nobel Laureate, who helped discover RNA interference (RNAi). Along with his colleague Andrew Fire, he developed gene knockouts using RNAi. In 006 Mello won the Nobel Prize in Physiology or Medicine for his contribution. Mello also contributed to developmental biology, focusing on gene regulation, cell signaling, cleavage formation, germline determination, cell migration, cell fate differentiation, and morphogenesis.

Format: Articles

Subject: People