From University to Court: The Reversal of Stahl's Positions on Gold-Making.

Georg Ernst Stahl, an influential chymical-medical author of the late seventeenth and early eighteenth centuries, first believed in alchemical transmutation and reversed his position over the course of his career. This essay begins by placing Stahl's early teaching in alchemy in a larger background in which German princes and academics shared intense interest in gold-making. Then, tracing Stahl's intellectual development, it shows that he developed an increasing reservation about alchemy, though he remained open to the possibility of transmutation during his tenure at Halle. Finally, this essay shows that Stahl's service to King Friedrich Wilhelm I was an important context for his later public denunciation of alchemy. An analysis of Stahl's career shift from a university professor to a royal physician at court thus sheds light on the reversal of his positions.

Integrated quantum dot barcode smartphone optical device for wireless multiplexed diagnosis of infected patients.

Inorganic nanoparticles are ideal precursors for engineering barcodes for rapidly detecting diseases. Despite advances in the chemical design of these barcodes, they have not advanced to clinical use because they lack sensitivity and are not cost-effective due to requirement of a large read-out system. Here we combined recent advances in quantum dot barcode technology with smartphones and isothermal amplification to engineer a simple and low-cost chip-based wireless multiplex diagnostic device. We characterized the analytical performance of this device and demonstrated that the device is capable of detecting down to 1000 viral genetic copies per milliliter, and this enabled the diagnosis of patients infected with HIV or hepatitis B. More importantly, the barcoding enabled us to detect multiple infectious pathogens simultaneously, in a single test, in less than 1 h. This multiplexing capability of the device enables the diagnosis of infections that are difficult to differentiate clinically due to common symptoms such as a fever or rash. The integration of quantum dot barcoding technology with a smartphone reader provides a capacity for global surveillance of infectious diseases and the potential to accelerate knowledge exchange transfer of emerging or exigent disease threats with healthcare and military organizations in real time.

Strategies for the intracellular delivery of nanoparticles.

The ability to target contrast agents and therapeutics inside cells is becoming important as we strive to decipher the complex network of events that occur within living cells and design therapies that can modulate these processes. Nanotechnology researchers have generated a growing list of nanoparticles designed for such applications. These particles can be assembled from a variety of materials into desirable geometries and configurations and possess useful properties and functionalities. Undoubtedly, the effective delivery of these nanomaterials into cells will be critical to their applications. In this tutorial review, we discuss the fundamental challenges of delivering nanoparticles into cells and to the targeted organelles, and summarize strategies that have been developed to-date.

Collaborative production and experimental labor: two models of dissertation authorship in the eighteenth century.

This article examines two early modern models of dissertation authorship that both relied on extensive collaboration between the degree candidate and his supervisor. The dissertation conducted on the traditional model, practiced until the eighteenth century at German universities, was a joint product of the supervisor, who prepared the thesis in writing, and the degree candidate, who defended it in the oral disputation. The two collaborators shared the credit for a successfully defended thesis in different forms: right for public recognition and rights to use and reproduce the thesis. Instead of sharing the credit as two equal partners, each of them took advantage of his credit in ways that benefited his status. In the model that Albrecht von Haller introduced at Göttingen, the supervisor provided the student with a laboratory and experimental training, while the degree candidate wrote a thesis by himself based on the experiments he carried out, and defended the thesis without the supervisor chairing the disputation. The Haller model reveals two new elements that heralded the development of modern scientific education: divisibility of laboratory labor between the student's experimentation and the research program to which it belongs; and feasibility of the requirement of experimental work in return for the exclusive authorship of the doctoral thesis.

Fermentation, phlogiston and matter theory: chemistry and natural philosophy in Georg Ernst Stahl's Zymotechnia Fundamentalis.

This paper examines Georg Ernst Stahl's first book, the Zymotechnia Fundamentalis, in the context of contemporary natural philosophy and the author's career. I argue that the Zymotechnia was a mechanical theory of fermentation written consciously against the influential "fermentational program" of Joan Baptista van Helmont and especially Thomas Willis, Stahl's theory of fermentation introduced his first conception of phlogiston, which was in part a corpuscular transformation of the Paracelsian sulphur principle. Meanwhile some assumptions underlying this theory, such as the composition of matter, the absolute passivity of matter and the "passions" of sulphur, reveal the combined scholastic and mechanistic character of Stahl's natural philosophy. In the conclusion I show that Stahl's theory of fermentation undermined the old fermentational program and paved the way for his dualist vitalism.