Simultaneous imaging and diffraction in the dynamic diamond anvil cell.

The ability to visualize a sample undergoing a pressure-induced phase transition allows for the determination of kinetic parameters, such as the nucleation and growth rates of the high-pressure phase. For samples that are opaque to visible light (such as metallic systems), it is necessary to rely on x-ray imaging methods for sample visualization. Here, we present an experimental platform developed at beamline P02.2 at the PETRA III synchrotron radiation source, which is capable of performing simultaneous x-ray imaging and diffraction of samples that are dynamically compressed in piezo-driven diamond anvil cells. This setup utilizes a partially coherent monochromatic x-ray beam to perform lensless phase contrast imaging, which can be carried out using either a parallel- or focused-beam configuration. The capabilities of this platform are illustrated by experiments on dynamically compressed Ga and Ar. Melting and solidification were identified based on the observation of solid/liquid phase boundaries in the x-ray images and corresponding changes in the x-ray diffraction patterns collected during the transition, with significant edge enhancement observed in the x-ray images collected using the focused-beam. These results highlight the suitability of this technique for a variety of purposes, including melt curve determination.

Energetics of polymeric carbon monoxide.

The transformation of carbon monoxide (CO) from a molecular liquid to a polymeric solid under isothermal compression at room temperature is investigated using first principles theory. We report structural and thermodynamic properties from ambient density up to 2.45 g/cc obtained using density functional theory molecular dynamics simulations, including hybrid exchange corrections. The theoretical results are compared with newly obtained polymeric CO samples, synthesized in a large volume press. The explosive performance of polymeric CO is predicted and discussed. Under most favorable assumptions, it is found to be comparable to trinitrotoluene.

Rectal perforation after aquablation of the prostate: lessons learned the hard way.

INTRODUCTION: Transurethral resection of the prostate and open prostatectomy have been the standard of care for the surgical treatment of benign prostatic obstruction (BPO) over decades. New emerging techniques for the surgical management of BPO have been currently introduced, but might be associated with new, unusual complications. METHODS: We herewith report on two patients with a rectal perforation after aquablation treatment of BPO. RESULTS: In the first case, the diagnosis was made 2 days after the aquablation procedure due to unspecific postoperative symptoms. A complex combined open/endoscopic repair of the defect was carried out thereafter. As a consequence, a rectoscopy was routinely performed since then following each aquablation procedure. In the second case, intraoperative rectoscopy after uneventful aquablation revealed the rectal perforation. The perforation was clipped immediately with an over the scope-clip by colonoscopy. CONCLUSIONS: These two cases of a rectal perforation after aquablation of the prostate demonstrate an unusual complication and its complex management. Diagnostic delay complicates its treatment. Therefore, immediate rectoscopy should be performed routinely after the aquablation procedure.

Advanced Spectral Analysis Program.

Advanced Spectral Analysis Program is a LabVIEW-based program intended for rapid and accurate analysis of large sets of spectral data. It can handle a range of different types of data including angle-resolved and energy-dispersive powder diffraction and Raman spectra. We present it here with a focus on high-temperature high-pressure powder diffraction. The program contains a novel graphical user interface that allows rapid manual fitting and indexing of peaks which require precise fitting ranges and includes tools for fitting any Bravais lattice and arbitrary user-defined multivariate equations of state. The program allows the user to simultaneously view and manipulate multiple data sets from an experiment. The user can save and load analysis progress at any point, allowing for repeatable calculations to be performed, and to allow the fast comparison of different analysis parameters.

Pressure Effects on the 4f Electronic Structure of Light Lanthanides.

Using the satellite structure of the Lγ_{1} line in nonresonant x-ray emission spectra, we probe the high-pressure evolution of the bare 4f signature of the early light lanthanides at ambient temperature. For Ce and Pr the satellite peak experiences a sudden reduction concurrent with their respective volume collapse (VC) transitions. These new experimental results are supported by calculations using state-of-the-art extended atomic structure codes for Ce and Pr, and also for Nd, which does not exhibit a VC. Our work suggests that changes to the 4f occupation are more consistently associated with evolution of the satellite than is the reduction of the 4f moment. Indeed, we show that in the case of Ce, mixing of a higher atomic angular momentum state, driven by the increased hybridization, acts to obscure the expected satellite reduction. These measurements emphasize the importance of a unified study of a full set of microscopic observables to obtain the most discerning test of the underlying, fundamental f-electron phenomena at high pressures.

Single crystal toroidal diamond anvils for high pressure experiments beyond 5 megabar.

Static compression experiments over 4 Mbar are rare, yet critical for developing accurate fundamental physics and chemistry models, relevant to a range of topics including modeling planetary interiors. Here we show that focused ion beam crafted toroidal single-crystal diamond anvils with ~9.0 µm culets are capable of producing pressures over 5 Mbar. The toroidal surface prevents gasket outflow and provides a means to stabilize the central culet. We have reached a maximum pressure of ~6.15 Mbar using Re as in situ pressure marker, a pressure regime typically accessed only by double-stage diamond anvils and dynamic compression platforms. Optimizing single-crystal diamond anvil design is key for extending the pressure range over which studies can be performed in the diamond anvil cell.

A simple and portable multi-channel pyrometer allowing temperature measurements down to 800 K on the microsecond scale.

The measurement of transient temperatures less than 1000 K for samples in laser-heated diamond anvil cells remains a challenge. Here we present the design and performance characteristics of a multi-channel pyrometer that works in the near-infrared from 1200 to 2000 nm. It has a relatively small footprint, is portable, requires only low voltage power supplies, and can report temperatures down to 800 K on the millisecond scale or faster. A single data point without averaging can be acquired in 14 µs (sampling rate of 7 kilosamples per second). In conjunction with a diamond anvil cell, the system delivers accurate and rapid measurements down to ∼830 K. The pyrometer has been successfully interfaced several times with the combined x-ray diffraction and laser heating system at the High Pressure Collaborative Access Team at the Advanced Photon Source at Argonne National Laboratories.

[Approach to liver, spleen and pancreatic injuries including damage control surgery of terrorist attacks]. / Vorgehen bei Leber­, Milz­ und Pankreasverletzungen inklusive "damage control surgery" bei Terroranschlägen.

BACKGROUND: Terrorist attacks have outreached to Europe with more and more attacks on civilians. Derived from war surgery experience and from lessons learned from major incidents, it seems mandatory for every surgeon to improve understanding of the special circumstances of trauma following a terrorist attack and its' management. METHOD: A short literature review is followed by outlining the damage control surgery (DCS) principle for each organ system with practical comments from the perspective of a specialized hepatobiliary (HPB) surgery unit. CONCLUSION: Every surgeon has to become familiar with the new entities of blast injuries and terrorist attack trauma. This concerns not only the medical treatment but also tailoring surgical treatment with a view to a lack of critical resources under these circumstances. For liver and pancreatic trauma, simple treatment strategies are a key to success.

[Chylous ascites and acute appendicitis - more than an accidental finding?]. / Chylöser Aszites bei akuter Appendizitis - Zufallsbefund oder ätiologischer Zusammenhang?

INTRODUCTION: Chylous ascites with a simultaneously presenting acute appendicitis is a uncommon finding which has been rarely reported in present literature. CASE REPORT: We present the case of a 36 years old patient showing the clinical signs of an acute appendicitis with an intraoperative finding of chylous ascites. DISCUSSION: The causing factors for chylous ascites are numerous, the clinical manifestations nonspecific. Thus the adequate diagnostic measures vary. The therapy is mainly based on medicational and dietary treatment but also benefits from a surgical approach.

A versatile medium-resolution x-ray emission spectrometer for diamond anvil cell applications.

We present design and performance details for a polycapillary-coupled x-ray spectrometer that provides very high collection efficiency at a moderate energy resolution suitable for many studies of nonresonant x-ray emission spectroscopy, especially for samples of heavy elements under high pressures. Using a single Bragg analyzer operating close to backscattering geometry so as to minimize the effect of the weak divergence of the quasicollimated exit beam from the polycapillary optic, this instrument can maintain a typical energy resolution of 5 eV over photon energies from 5 keV to 10 keV. We find dramatically improved count rates as compared to a traditional higher-resolution instrument based on a single spherically bent crystal analyzer.

Strength and Debye temperature measurements of cerium across the γ → α volume collapse: the lattice contribution.

The longitudinal and transverse sound speeds, cL and cT, of polycrystalline cerium were measured under pressure across the iso-structural γ-α phase transition at 0.75 GPa to beyond 3 GPa. In contrast to previous methods all quantities were directly obtained and no assumptions were made about the size of the volume collapse. Up to the transition our values for cL are in excellent agreement with previous ones, while our values for cT are significantly lower. We deduce values for the adiabatic bulk modulus BS, the shear modulus [Formula: see text], and the pressure dependent Debye temperature, ΘD(p). ΘD(p) is in good agreement with recent results derived from phonon dispersion measurements on single crystals. The ratio of the Debye temperature values bracketing the transition indicates a lattice contribution to the entropy change across the volume collapse, ΔSvib(γ â†’ α) ≈ (0.68 ± 0.06)kB, consistent with previous results obtained by neutron scattering, but significantly larger than other previously determined values.

X-ray emission spectroscopy of cerium across the γ-α volume collapse transition.

High-pressure x-ray emission measurements are used to provide crucial evidence in the longstanding debate over the nature of the isostructural (α, γ) volume collapse in elemental cerium. Extended local atomic model calculations show that the satellite of the Lγ emission line offers direct access to the total angular momentum observable (J(2)). This satellite experiences a 30% steplike decrease across the volume collapse, validating the Kondo model in conjunction with previous measurements. Direct comparisons are made with previous predictions by dynamical mean field theory. A general experimental methodology is demonstrated for analogous work on a wide range of strongly correlated f-electron systems.

[EHEC-associated colon stenosis after ulcerous-chronic haemorrhagic colitis and consecutive resulting ileus]. / EHEC-assoziierte Kolonstenose nach ulzerös-chronisch hämorrhagischer Kolitis mit konsekutivem Ileus.

We report on the case of a segmentally emphasised, ulcerous chronic haemorrhagic colitis with the development of granulation tissue und scarred fibrosis with consecutive resulting stenosis of the colon. A 49-year-old male patient was infected with enterohaemorrhagic Escherichia coli bacteria during the EHEC-epidemic in northern Germany in early summer 2011. In the course of the infection the patient suffered from haemolytic uraemic syndrome (HUS) with acute renal failure and neurological symptoms. Haemodialysis and plasmapheresis had become mandatory. A simultaneous ileus was estimated to be of paralytic origin. One month after treatment of the acute phase of the infection a CT scan of the abdomen was performed and discovered a symptomatic stenosis of the proximal colon transversum. This obstruction needed to be treated by performing a right hemicolectomy with an ileo-transverso anastomosis. After surgery the patient recovered continuously. The histopathological examination verified an ulcerous-chronic haemorrhagic colitis on the background of an EHEC infection.

A miniature X-ray emission spectrometer (miniXES) for high-pressure studies in a diamond anvil cell.

Core-shell X-ray emission spectroscopy (XES) is a valuable complement to X-ray absorption spectroscopy (XAS) techniques. However, XES in the hard X-ray regime is much less frequently employed than XAS, often as a consequence of the relative scarcity of XES instrumentation having energy resolutions comparable with the relevant core-hole lifetimes. To address this, a family of inexpensive and easily operated short-working-distance X-ray emission spectrometers has been developed. The use of computer-aided design and rapid prototype machining of plastics allows customization for various emission lines having energies from ∼3 keV to ∼10 keV. The specific instrument described here, based on a coarsely diced approximant of the Johansson optic, is intended to study volume collapse in Pr metal and compounds by observing the pressure dependence of the Pr Lα emission spectrum. The collection solid angle is ∼50 msr, roughly equivalent to that of six traditional spherically bent crystal analyzers. The miniature X-ray emission spectrometer (miniXES) methodology will help encourage the adoption and broad application of high-resolution XES capabilities at hard X-ray synchrotron facilities.

Thermal signatures of the Kondo volume collapse in cerium.

X-ray diffraction measurements of cerium in the vicinity of the isostructural gamma-alpha transition have been performed with high precision and accuracy from room temperature to almost 800 K. The disputed location of the critical point has been found to occur at 1.5+/-0.1 GPa and 480+/-10 K. The data are well fit by the Kondo volume collapse model plus a quasiharmonic representation of the phonons. The resultant free energy is validated against data for the thermodynamic Grüneisen parameter and, beyond the dominant spin-fluctuation contribution, indicates a dramatic change in the lattice Grüneisen parameter across the transition.

Temporomandibular symptoms and occlusion: a review of the literature & the concept.

The role of occlusal factors in the etiology of temporomandibular disorders (TMD) is reviewed. The rediscovery of TMD by J. B. Costen in 1934 and the origin of this concept are historically linked. Difficulties in scientifically studying TMD are addressed. TMD lacks specific indicators (signs and symptoms), are episodic and respond to placebos. Clinical success with specific literature (experimental, epidemiological and clinical studies) reviewed fails to support the concept that occlusal factors play a significant role in the etiology of TMD. The remodeling capacity of the temporomandibular joint demonstrates that the joint can accommodate and adapt to various occlusal conditions.

Temporomandibular symptoms and occlusion: a review of the literature & the concept.

The role of occlusal factors in the etiology of temporomandibular disorders (TMD) is reviewed. The rediscovery of TMD by J.B. Costen in 1934 and the origin of this concept are historically linked. Difficulties in scientifically studying TMD are addressed. TMD lacks specific indicators (signs and symptoms), are episodic and respond to placebos. Clinical success with specific literature (experimental, epidemiological and clinical studies) reviewed fails to support the concept that occlusal factors play a significant role in the etiology of TMD. The remodeling capacity of the temporomandibular joint demonstrates that the joint can accommodate and adapt to various occlusal conditions.

The oral-facial-digital syndrome: case report of a mother and daughter.

A case report of a daughter and mother with the oral-facial digital syndrome, type I, is presented. The features were variable between the two cases. The daughter had a previously unreported feature, ridging of the metopic suture. Hand-wrist radiographs of both the patient and mother demonstrated a normal trabeculation pattern, contradicting the suggestion of Anneren et al (1984) that irregular mineralization of the hands is pathognomonic for the OFD I syndrome.

An impression procedure for the neonatal patient with a cleft palate.

An impression procedure for the neonatal patient with a cleft palate is described. The procedure has been used at Beth Israel Medical Center, New York City, for the past 10 years and has been proved safe, reliable, and precise.