The Pyrococcus furiosus ironome is dominated by [Fe4S4]2+ clusters or thioferrate-like iron depending on the availability of elemental sulfur.

Pyrococcus furiosus is a hyperthermophilic anaerobic archaeon whose metabolism depends on whether elemental sulfur is (+S0) or is not (-S0) included in growth medium. Under +S0 conditions, expression of respiratory hydrogenase declines while respiratory membrane-bound sulfane reductase and the putative iron-storage protein IssA increase. Our objective was to investigate the iron content of WT and ΔIssA cells under these growth conditions using Mössbauer spectroscopy. WT-S0 cells contained ∼1 mM Fe, with ∼85% present as two spectroscopically distinct forms of S = 0 [Fe4S4]2+ clusters; the remainder was mainly high-spin FeII. WT+S0 cells contained 5 to 9 mM Fe, with 75 to 90% present as magnetically ordered thioferrate-like (TFL) iron nanoparticles. TFL iron was similar to chemically defined thioferrates; both consisted of FeIII ions coordinated by an S4 environment, and both exhibited strong coupling between particles causing high applied fields to have little spectral effect. At high temperatures with magnetic hyperfine interactions abolished, TFL iron exhibited two doublets overlapping those of [Fe4S4]2+ clusters in -S0 cells. This coincidence arose because of similar coordination environments of TFL iron and cluster iron. The TFL structure was more heterogeneous in the presence of IssA. Presented data suggest that IssA may coordinate insoluble iron sulfides as TFL iron, formed as a byproduct of anaerobic sulfur respiration under high iron conditions, which thereby reduces its toxicity to the cell. This was the first Mössbauer characterization of the ironome of an archaeon, and it illustrates differences relative to the iron content of better-studied bacteria such as Escherichia coli.

Biographical sketch: John Albert Key, 1890-1955.

This biographical sketch on John Albert Key corresponds to the historic text, The Classic: Epiphyseal coxa vara or displacement of the capital epiphysis of the femur in adolescence, available at DOI 10.1007/s11999-013-2913-y.

Biographical sketch: Ernest Amory Codman, MD (1869-1940).

This biographical sketch on E.A. Codman corresponds to the historic text, The Classic: A Study in Hospital Efficiency: As Demonstrated by the Case Report of the First Five Years of a Private Hospital (1918), available at DOI 10.1007/s11999-012-2751-3.

Biographical sketch: Franz König, MD 1832-1910.

This biographical sketch on Franz König corresponds to the historic text, The Classic: Ueber freie Körper in den Gelenken [On loose bodies in the joint] (1887), available at DOI 10.1007/s11999-013-2824-y (Translated by Drs. Richard A. Brand and Christian-Dominik Peterlein).

Biographical sketch: Harald Tscherne, MD (1933-present).

This biographical sketch on Prof. Harald Tscherne corresponds to the historic text, The Classic: Der Straßenunfall [Traffic Accidents]. Wien Med Wochenschr. 1966;116:105-108 (Translated by Dr. Roman Pfeifer), available at DOI 10.1007/s11999-013-3012-9.

Formation of precipitates in off-stoichiometric Ni-Mn-Sn Heusler alloys probed through the induced Sn-moment.

The shell-ferromagnetic effect originates from the segregation process in off-stoichiometric Ni-Mn-based Heusler alloys. In this work, we investigate the precipitation process of L21-ordered Ni2MnSn and L10-ordered NiMn in off-stoichiometric Ni50Mn45Sn5 during temper annealing, by X-ray diffraction (XRD) and 119Sn Mössbauer spectroscopy. While XRD probes long-range ordering of the lattice structure, Mössbauer spectroscopy probes nearest-neighbour interactions, reflected in the induced Sn magnetic moment. As shown in this work, the induced magnetic Sn moment can be used as a detector for microscopic structural changes and is, therefore, a powerful tool for investigating the formation of nano-precipitates. Similar research can be performed in the future, for example, on different pinning type magnets like Sm-Co or Nd-Fe-B.

Biographical sketch: Georg Clemens Perthes, MD (1869-1927).

This biographical sketch on Georg Perthes corresponds to the historic text, The Classic: On Juvenile Arthritis Deformans (1910), available at DOI 10.1007/s11999-012-2433-1.

Biographical sketch: Thomas W. Huntington, MD (1849-1929).

This biographical sketch on Thomas Huntington corresponds to the historic text, The classic: case of bone transference. use of a segment of fibula to supply a defect in the tibia (1905), available at DOI 10.1007/s11999-012-2496-z .

Biographical sketch: William John Little, FRCS (1810-1894).

This biographical sketch on William Little corresponds to the historic text, The Classic: Hospital for the Cure of Deformities: Course of Lectures on the Deformities of the Human Frame (1843), available at DOI 10.1007/s11999-012-2302-y .

Biographical sketch: George E. Bennett, MD (1885-1962).

This biographical sketch on George Bennett corresponds to the historic text, The Classic: Shoulder and Elbow Lesions Distinctive of Baseball Players (1947), available at DOI 10.1007/s11999-012-2335-2 .

Biographical sketch: Frank Wild Holdsworth, FRCS (1904-1969).

This biographical sketch on Frank Holdsworth corresponds to the historic text, The Classic: Dislocation and fracture-dislocation of the pelvis (1948), available at DOI 10.1007/s11999-012-2423-3 .

Biographical sketch: Charles Hewitt Moore, FRCS (1821-1870).

This biographical sketch on Charles Moore corresponds to the historic text, The Classic: An account of a Case of Fracture and Distortion of the Pelvis, combined with an unusual form of Dislocation of the Femur (1851), available at DOI 10.1007/s11999-012-2425-1 .

Reviewing for clinical orthopaedics and related research.

Peer review in science was established in the 17th Century and while not without detractors and some controversy, has been a mainstay of high-quality scientific publications ever since. Most believe peer review adds substantially to the value of papers that achieve publication. However, in practice, peer review can be practiced with varying degrees of rigor and the value of the review depends on rigor. The two primary tasks of a reviewer are to determine whether the manuscript makes a substantial contribution (in an age of information overload) and to determine whether there are any "fatal" flaws. If the reviewer recommends rejection, then he or she need only note the major flaws. If, however, the material is sufficiently novel and would substantially add to the literature, the reviewer's secondary task is to ensure completeness and clarity by noting information that should be added and identifying unclear points; in these cases more detailed reviews are merited. To achieve this task, the reviewer must ask numerous questions related to the background and rationale, questions or purposes, study design and methods, findings, and synthesis with the literature. In this brief review I outline such key questions. An invitation to review is an honor and reflects the confidence of the editor in the reviewer's expertise and accomplishments. Given proper reviews and recommendations, the majority of authors believe peer review adds great value to their papers and the reviewer makes contributions to the community and their own knowledge.

Creating a Ferromagnetic Ground State with Tc Above Room Temperature in a Paramagnetic Alloy through Non-Equilibrium Nanostructuring.

Materials with strong magnetostructural coupling have complex energy landscapes featuring multiple local ground states, thus making it possible to switch among distinct magnetic-electronic properties. However, these energy minima are rarely accessible by a mere application of an external stimuli to the system in equilibrium state. A ferromagnetic ground state, with Tc above room temperature, can be created in an initially paramagnetic alloy by nonequilibrium nanostructuring. By a dealloying process, bulk chemically disordered FeRh alloys are transformed into a nanoporous structure with the topology of a few nanometer-sized ligaments and nodes. Magnetometry and Mössbauer spectroscopy reveal the coexistence of two magnetic ground states, a conventional low-temperature spin-glass and a hitherto-unknown robust ferromagnetic phase. The emergence of the ferromagnetic phase is validated by density functional theory calculations showing that local tetragonal distortion induced by surface stress favors ferromagnetic ordering. The study provides a means for reaching conventionally inaccessible magnetic states, resulting in a complete on/off ferromagnetic-paramagnetic switching over a broad temperature range.

A Unique Mechanochemical Redox Reaction Yielding Nanostructured Double Perovskite Sr2FeMoO6 With an Extraordinarily High Degree of Anti-Site Disorder.

Strontium ferromolybdate, Sr2FeMoO6, is an important member of the family of double perovskites with the possible technological applications in the field of spintronics and solid oxide fuel cells. Its preparation via a multi-step ceramic route or various wet chemistry-based routes is notoriously difficult. The present work demonstrates that Sr2FeMoO6 can be mechanosynthesized at ambient temperature in air directly from its precursors (SrO, α-Fe, MoO3) in the form of nanostructured powders, without the need for solvents and/or calcination under controlled oxygen fugacity. The mechanically induced evolution of the Sr2FeMoO6 phase and the far-from-equilibrium structural state of the reaction product are systematically monitored with XRD and a variety of spectroscopic techniques including Raman spectroscopy, 57Fe Mössbauer spectroscopy, and X-ray photoelectron spectroscopy. The unique extensive oxidation of iron species (Fe0 → Fe3+) with simultaneous reduction of Mo cations (Mo6+ → Mo5+), occuring during the mechanosynthesis of Sr2FeMoO6, is attributed to the mechanically triggered formation of tiny metallic iron nanoparticles in superparamagnetic state with a large reaction surface and a high oxidation affinity, whose steady presence in the reaction mixture of the milled educts initiates/promotes the swift redox reaction. High-resolution transmission electron microscopy observations reveal that the mechanosynthesized Sr2FeMoO6, even after its moderate thermal treatment at 923 K for 30 min in air, exhibits the nanostructured nature with the average particle size of 21(4) nm. At the short-range scale, the nanostructure of the as-prepared Sr2FeMoO6 is characterized by both, the strongly distorted geometry of the constituent FeO6 octahedra and the extraordinarily high degree of anti-site disorder. The degree of anti-site disorder ASD = 0.5, derived independently from the present experimental XRD, Mössbauer, and SQUID magnetization data, corresponds to the completely random distribution of Fe3+ and Mo5+ cations over the sites of octahedral coordination provided by the double perovskite structure. Moreover, the fully anti-site disordered Sr2FeMoO6 nanoparticles exhibit superparamagnetism with the blocking temperature T B = 240 K and the deteriorated effective magnetic moment µ = 0.055 µ B per formula unit.

Biographical sketch: George L. Walton, MD and Walter E. Paul, MD.

This biographical sketch on George L. Walton and Walter E. Paul corresponds to the historic text, The Classic: Contribution to the Study of Spinal Surgery: One Successful and One Unsuccessful Operation for Removal of Tumor (1905), available at DOI 10.1007/s11999-010-1664-2 .

Biographical sketch: John Caffey, MD (1895-1978).

This biographical sketch on John Caffey corresponds to the historic text, The Classic: Multiple Fractures in the Long Bones of Infants Suffering From Chronic Subdural Hematoma (1946), available at DOI 10.1007/s11999-010-1666-0 .

Biographical sketch: William Russell MacAusland, MD 1882-1965.

This biographical sketch on William Russell MacAusland corresponds to the historic text, The Classic: Total Replacement of the Knee Joint by a Prosthesis, available at DOI 10.1007/s11999-010-1305-9 .

Biographical sketch: John Royal Moore, MD 1899-1988.

This biographical sketch on John R. Moore corresponds to the historic text, The Classic: Cartilaginous-cup Arthroplasty in Ununited Fractures of the Neck of the Femur (1948), available at DOI 10.1007/s11999-011-1974-z.

Biographical sketch: Thomas Callaway, FRCS (1822-1869).

This biographical sketch on Thomas Callaway corresponds to the historic text, The Classic: A Dissertation Upon Dislocations and Fractures of the Clavicle and Shoulder-Joint (1849) available at DOI 10.1007/s11999-011-2098-1 .