5,716 research outputs found
John Blair Deaver, M.D., and his marvelous retractor.
John Blair Deaver was born near Buck, Pennsylvania, in Lancaster County on July 25, 1855, to Dr. Joshua Montgomery Deaver and Elizabeth Clair Moore. The elder Deaver was a reputable country physician, educated at the University of Maryland, who fathered three physicians and a college president. John Blair Deaver (Fig. 1) went to boarding school at West Nottingham Academy in Maryland. After boarding school he taught in Lancaster County country schools to raise funds to attend the nation’s first medical school, the University of Pennsylvania. On receiving his M.D. degree in 1878, Dr. Deaver completed 1-year internships at both Germantown Hospital and Philadelphia Children’s Hospital, after which he embarked into clinical practice. Alongside his brother, Dr. Harry Clay Deaver, he made home visits to patients to perform surgeries as well as managed a busy 16th Street and Vine Street Philadelphia office
Concurrent Magnetic and Metal-Insulator Transitions in (Eu,Sm)B_6 Single Crystals
The effects of magnetic doping on a EuB_6 single crystal were investigated
based on magnetic and transport measurements. A modest 5% Sm substitution for
Eu changes the magnetic and transport properties dramatically and gives rise to
concurrent antiferromagnetic and metal-insulator transitions (MIT) from
ferromagnetic MIT for EuB6. Magnetic doping simultaneously changes the
itinerant carrier density and the magnetic interactions. We discuss the origin
of the concurrent magnetic MIT in (Eu,Sm)B_6.Comment: 13 pages, 3 figures, final version to appear in Appl. Phys. Lett
John H. Gibbon, Jr., M.D.: surgical innovator, pioneer, and inspiration.
Throughout history there have been many discoveries that have changed the world, including Albert Einstein’s theory of relativity, Alexander Graham Bell’s telephone, and Jack Kilby and Robert Noyce’s microchip. There are a few analogous contributions that have been made in medicine: Sir Alexander’s discovery of penicillin, Lister’s principles of antiseptic technique, Salk and Sabin’s vaccines for polio, as well as numerous others. These innovative thinkers all had two factors in common. First, they were pioneers who faced problems that had no solutions at the time and who refused to accept the status quo in the face of great scrutiny and resistance. Second, their contributions would forever change the world. In 1930, a profound experience with a patient would forever change Dr. John H. Gibbon, Jr. and stimulate an idea to create a device that at the time sounded audacious and impossible. His device would temporarily take the role of both the heart and lungs to make repairs inside the heart or the great vessels. Twentythree years later, Dr. Gibbon used his machine to perform the first successful bypass-assisted open heart surgery
John Y. Templeton III: Pioneer of modern cardiothoracic surgery.
John Young Templeton III was born in 1917 in Portsmouth, Virginia, and graduated from Jefferson Medical College in 1941. He completed his residency training under Dr. John H. Gibbon, Jr., and was the first resident who worked on Gibbon\u27s heart-lung machine. After his training, he remained at Jefferson as an American Cancer Society fellow and Damon Runyon fellow and went on to become the fourth Samuel D. Gross Professor and Chair of the Department of Surgery in 1967. Dr. Templeton was the recipient of numerous grants and published over 80 papers in the field of cardiothoracic surgery. As a teacher and mentor, he was a beloved figure who placed great faith in his residents. He participated in over 60 professional societies, serving as president to many such as the Philadelphia Academy of Surgery and the Pennsylvania Association of Thoracic Surgery. He was also recognized through his many awards, in particular the John Y. Templeton III lectureship established in 1980 at Jefferson of whom Denton Cooley was the first lecturer. Dr. Templeton retired from practice in 1987. He is forever remembered as an important model of a modern surgeon evident in numerous academic achievements, the admiration and affection of his trainees, and the lives of patients that he had touched
Simple Ginzburg-Landau Theory for Vortices in a Crystal Lattice
We study the Ginzburg-Landau model with a nonlocal quartic term as a simple
phenomenological model for superconductors in the presence of coupling between
the vortex lattice and the underlying crystal lattice. In mean-field theory,
our model is consistent with a general oblique vortex lattice ranging from a
triangular lattice to a square lattice. This simple formulation enables us to
study the effect of thermal fluctuations in the vortex liquid regime. We
calculate the structure factor of the vortex liquid nonperturbatively and find
Bragg-like peaks with four-fold symmetry appearing in the structure factor even
though there is only a short-range crystalline order.Comment: Revised version with new title and additional results for the vortex
liquid regime, to be published in Phys. Rev. Lett. 5 pages RevTeX, 1 figure
include
Pattern formation of indirect excitons in coupled quantum wells
Using a nonlinear Schr\"odinger equation including short-range two-body
attraction and three-body repulsion, we investigate the spatial distribution of
indirect excitons in semiconductor coupled quantum wells. The results obtained
can interpret the experimental phenomenon that annular exciton cloud first
contracts then expands when the number of confined excitons is increased in
impurity potential well, as observed by Lai \emph{et al.} [Lai ,
Science \textbf{303}, 503 (2004)]. In particular, the model reconciles the
patterns of exciton rings reported by Butov \emph{et al.} [Butov ,
Nature \textbf{418}, 751 (2002)]. At higher densities, the model predicts much
richer patterns, which could be tested by future experiments.Comment: 5 Revtex4 pages, 3 figure
Non-commutative field theory approach to two-dimensional vortex liquid system
We investigate the non-commutative (NC) field theory approach to the vortex
liquid system restricted to the lowest Landau level (LLL) approximation. NC
field theory effectively takes care of the phase space reduction of the LLL
physics in a -product form and introduces a new gauge invariant form of
a quartic potential of the order parameter in the Ginzburg-Landau (GL) free
energy. This new quartic interaction coupling term has a non-trivial
equivalence relation with that obtained by Br\'ezin, Nelson and Thiaville in
the usual GL framework. The consequence of the equivalence is discussed.Comment: Add vortex lattice formation, more references, and one autho
Is chloride toxic to seed germination in mixed-salt environments? A case study with the coastal halophyte Suaeda maritima in the presence of seawater
Abstract Most salt tolerant plants, halophytes, use seed germination for natural regeneration. However, germination in mixed-salt environments such as seawater is poorly understood and ion toxicity by Cl−, the most highly concentrated ion in seawater, is rarely considered over Na+. Here, we investigate Cl− toxicity in the germination of the halophyte Suaeda maritima in the presence of artificial seawater (ASW). Seeds were germinated at 15/5 °C in dilutions of ASW and at concentrations of NaCl, MgCl2, CaCl2 and KCl as found in ASW. Solutions of polyethylene glycol (PEG) were used for osmotic comparison. Germination percentage and normal seedlings were quantified. Non-germinated seeds were tested for recovery on water. Germination rate (1/t50) was used in a halotime model to quantify the maximum concentration of Cl− (Cl−max) and Na+ (Na+max) for germination. Germination was most negatively affected when all salts were combined in the concentrations found in ASW. Recovery of non-germinated seeds from all salt treatments on water was low, but all germinated seeds formed normal seedlings. Germination on ASW was higher than on iso-osmotic solutions of PEG. The 1/t50 decreased with increasing Cl− and Na+ concentration, indicating maximum thresholds to germination at 1381 mM (Cl−max) and 1262 mM (Na+max). The results indicate that ASW does not produce an osmotic limitation to the germination of S. maritima, and exposure to salt ions can even promote germination. However, ion toxicity is the major limitation, with Cl− similarly as toxic as Na+. In mixed-salt environments such as seawater, Cl− toxicity should not be overlooked
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