Recent developments in the Inorganic Crystal Structure Database: theoretical crystal structure data and related features

The Inorganic Crystal Structure Database (ICSD) is the world's largest database of fully evaluated and published crystal structure data, mostly obtained from experimental results. However, the purely experimental approach is no longer the only route to discover new compounds and structures. In the past few decades, numerous computational methods for simulating and predicting structures of inorganic solids have emerged, creating large numbers of theoretical crystal data. In order to take account of these new developments the scope of the ICSD was extended in 2017 to include theoretical structures which are published in peer-reviewed journals. Each theoretical structure has been carefully evaluated, and the resulting CIF has been extended and standardized. Furthermore, a first classification of theoretical data in the ICSD is presented, including additional categories used for comparison of experimental and theoretical information.

On the residual six-fold astigmatism in DCOR/ASCOR

After the introduction of the hexapole C_s-correctors for scanning transmission electron microscopes (STEM), the next big step forward was the strong reduction of the six-fold astigmatism A₅ by means of an advanced hexapole design (DCOR/ASCOR). As a result all axial aberrations up to fifth order are sufficiently small to allow for large semi-aperture angles beyond 40 mrad for electron energies in the range of 30 to 300 kV without deterioration of the STEM resolution. In this paper we derive simple expressions for the optimum hexapole strength for minimum A₅ and the size of the residual A₅. Both quantities are intrinsic properties of the hexapoles and the transfer lens doublet in between. The optimum hexapole strength scales with the inverse of the electron wavelength, while the residual A₅ does not depend on the electron energy directly, but on the spherical aberration C_s of the pole piece. With the given properties of the DCOR/ASCOR and typical values of C_s in the range of 0.5 to 2.7 mm, at all acceleration voltages A₅ remains in the range from 0.03 to 0.4 mm, the latter even for a large-gap pole piece.

Evaluation of arterial digital blood flow in dairy cows with claw horn disruption lesions using Doppler ultrasonography

Vascular changes play an important role in the pathogenesis of claw horn disruption lesions in cattle. The aim of the study was to measure arterial blood flow in the hind limbs of German Holstein cows with claw horn disruption lesions. A 10-MHz linear transducer was used to assess blood flow in the interdigital artery in the dorsal pastern region in the hind limbs of 11 non-lame and 33 lame German Holstein cows in which lameness was scored clinically. Qualitative and quantitative blood flow parameters were compared in affected limbs and unaffected contralateral hind limbs in lame cows and in the hind limbs of lame cows and non-lame cows. A pulsed-wave Doppler signal suitable for analysis was obtained in 78 of 88 limbs (33 affected and contralateral limbs, 22 limbs of control cows). Blood flow curve types 1 and 2 were predominant in the hind limbs of lame cows. Vessel diameter, end-diastolic velocity, and blood flow rate were significantly greater in lame cows than in non-lame cows and were numerically greater in moderately lame cows than in mildly lame cows. The differences in the qualitative and quantitative parameters between lame and non-lame cows were most likely caused by inflammation of the pododerm. The role of weight distribution between the paired hind limbs and the existence of claw horn disruption appeared to have an effect on the differences in local circulation in the affected and unaffected contralateral hind limbs in lame cows.

Evaluation of arterial digital blood flow in dairy cows with claw horn disruption lesions using Doppler ultrasonography

Vascular changes play an important role in the pathogenesis of claw horn disruption lesions in cattle. The aim of the study was to measure arterial blood flow in the hind limbs of German Holstein cows with claw horn disruption lesions. A 10-MHz linear transducer was used to assess blood flow in the interdigital artery in the dorsal pastern region in the hind limbs of 11 non-lame and 33 lame German Holstein cows in which lameness was scored clinically. Qualitative and quantitative blood flow parameters were compared in affected limbs and unaffected contralateral hind limbs in lame cows and in the hind limbs of lame cows and non-lame cows. A pulsed-wave Doppler signal suitable for analysis was obtained in 78 of 88 limbs (33 affected and contralateral limbs, 22 limbs of control cows). Blood flow curve types 1 and 2 were predominant in the hind limbs of lame cows. Vessel diameter, end-diastolic velocity, and blood flow rate were significantly greater in lame cows than in non-lame cows and were numerically greater in moderately lame cows than in mildly lame cows. The differences in the qualitative and quantitative parameters between lame and non-lame cows were most likely caused by inflammation of the pododerm. The role of weight distribution between the paired hind limbs and the existence of claw horn disruption appeared to have an effect on the differences in local circulation in the affected and unaffected contralateral hind limbs in lame cows.

Magnetic Cc/Cs-corrector compensating for the chromatic aberration and the spherical aberration of electron lenses

Aberration correction in transmission electron microscopy has proven feasible and useful over a large range of acceleration voltages. The spherical aberration has been corrected for beam energies from 15 kV [1] up to 1.2 MeV [2] while the correction of the chromatic aberration has been achieved for beam energies ranging from 20 kV[3] up to 300 kV[4]. Above this threshold the conventional correction principle based on mixed electric and magnetic focusing elements becomes infeasible with present technology [5]. For conventional electron sources at high voltages the relative energy width of the beam gets so small that chromatic correction becomes less important. Nevertheless, for new applications with pulsed electron sources with energy spreads in the order of 100 eV chromatic aberration will become a limiting factor even at high energies [6]. To enable chromatic aberration correction for such systems a novel type of a feasible, purely magnetic multipole aberration corrector with curved optic axis is proposed which is capable of compensating for the chromatic and spherical aberration up to several MeV.

Evidence for the Existence of Foetal Fibrinogen

Human fibrinogen was isolated from the blood of adults and from umbilical cord blood. The fibrinogen preparations obtained were clottable with thrombin to between 97 and 98% and homogeneous in acrylamide gel electrophoresis. Comparative analyses of these highly purified foetal and adult fibrinogen showed that they have the same quantitative amino acid composition and the same mobility in acrylamide gel electrophoresis at pH 9.2.

Chromatography on DEAE-cellulose made it likely that foetal and adult fibrinogen have a slightly different electrical charge. The pH-dependency of the thrombin clotting time is strikingly different. The fingerprints of the tryptic peptides showed at least 3 peptides with different mobility in chromatography.

From these data it is assumed that foetal and adult fibrinogen have a different molecular structure. Hitherto it cannot be decided if the two proteins have a different primary structure, which is most probable, or if they are chemical modifications.

Boron-phil and boron-phob structure units in novel borides Ni3Zn2B and Ni2ZnB: experiment and first principles calculations

The crystal structures of two novel borides in the Ni-Zn-B system, τ₅-Ni₃Zn₂B and τ₆-Ni₂ZnB, were determined by single crystal X-ray diffraction (XRSC) in combination with selected area electron diffraction in a transmission electron microscope (SAED-TEM) and electron probe microanalysis (EPMA). Both compounds crystallize in unique structure types (space group C2/m, a = 1.68942(8) nm, b = 0.26332(1) nm, c = 0.61904(3) nm, β = 111.164(2)°, R_F = 0.0219 for Ni₃Zn₂B, and space group C2/m, a = 0.95296(7) nm, b = 0.28371(2) nm, c = 0.59989(1) nm, β = 93.009(4)°, R_F = 0.0163 for Ni₂ZnB). Both compounds have similar building blocks: two triangular prisms centered by boron atoms are arranged along the c-axis separated by Zn layers, which form empty octahedra connecting the boron centered polyhedra. Consistent with the (Ni+Zn)/B ratio, isolated boron atoms are found in τ₅-Ni₃Zn₂B, while B-B pairs exist in τ₆-Ni₂ZnB. The crystal structure of Ni₂ZnB is closely related to that of τ₄-Ni₃ZnB₂, i.e. Ni₂ZnB can be formed by removing the nearly planar nickel layer in Ni₃ZnB₂ and shifting the origin of the unit cell to the center of the B-B pair. The electrical resistivity and specific heat of τ₅-Ni₃Zn₂B reveal the metallic behavior of this compound with an anomaly at low temperature, possibly arising from a Kondo-type interaction. Further analysis on the lattice contribution of the specific heat reveals similarity with τ₄-Ni₃ZnB₂ with some indications of lattice softening in τ₅-Ni₃Zn₂B, which could be related to the increasing metal content and the absence of B-B bonding in τ₅-Ni₃Zn₂B. For the newly found phases, τ₅-Ni₃Zn₂B and τ₆-Ni₂ZnB as well as for τ₃-Ni₂₁Zn₂B₂₀ and τ₄-Ni₃ZnB₂ density functional theory (DFT) calculations were performed by means of the Vienna Ab initio Simulation Package (VASP). Total energies and forces were minimized in order to determine the fully relaxed structural parameters, which agree very well with experiment. Energies of formations in the range of -25.2 to -26.9 kJ mol^-1 were calculated and bulk moduli in the range of 179.7 to 248.9 GPa were derived showing hardening by increasing the B concentration. Charge transfer is discussed in terms of Bader charges resulting in electronic transfer from Zn to the system and electronic charge gain by B. Ni charge contributions vary significantly with crystallographic position depending on B located in the neighbourhood. The electronic structure is presented in terms of densities of states, band structures and contour plots revealing Ni-B and Ni-Zn bonding features.

Sensors, Medical Images and Signal Processing:

Objectives To summarize current excellent research in the field of medical sensor, signal and imaging informatics.

Method: Synopsis of the articles selected for the IMIA (International Medical Informatics Association) Yearbook 2010.

Results: Current research in the field of sensor, signal, and imaging informatics is characterized by theoretically sound techniques and evaluations with focus in imaging informatics.

Conclusions: The best paper selection of articles on sensors, signal, and imaging informatics shows examples of excellent research on methods concerning theoretically sound original development in this field. Research published in 2009 was characterized by the emergence of mature computerized diagnosis aid frameworks with assessment of input and output quality. The purpose of these systems is clearly to bring new image and signal interpretation tools to clinicians.

Clinical Data Mining: a Review

Objective Clinical data mining is the application of data mining techniques using clinical data. We review the literature in order to provide a general overview by identifying the status-of-practice and the challenges ahead.

Methods The nine data mining steps proposed by Fayyad in 1996 [4] were used as the main themes of the review. MEDLINE was used as primary source and 84 papers were retained based on our inclusion criteria.

Results Clinical data mining has three objectives: understanding the clinical data, assist healthcare professionals, and develop a data analysis methodology suitable for medical data. Classification is the most frequently used data mining function with a predominance of the implementation of Bayesian classifiers, neural networks, and SVMs (Support Vector Machines). A myriad of quantitative performance measures were proposed with a predominance of accuracy, sensitivity, specificity, and ROC curves. The latter are usually associated with qualitative evaluation.

Conclusion Clinical data mining respects its commitment to extracting new and previously unknown knowledge from clinical databases. More efforts are still needed to obtain a wider acceptance from the healthcare professionals and for generalization of the knowledge and reproducibility of its extraction process: better description of variables, systematic report of algorithm parameters including the method to obtain them, use of easy-to-understand models and comparisons of the efficiency of clinical data mining with traditional statistical analyses. More and more data will be available for data miners and they have to develop new methodologies and infrastructures to analyze the increasingly complex medical data.

A User-oriented Protocol for Integrating Heterogeneous Communication Systems of Medical Facilities Using Ports

The crucial feature of future communication systems in hospitals will be the heterogeneity between the individual systems. People working in a hospital do not communicate via data objects, but via highly complex functions like preparation of a patient report or diagnosis of patients’ symptoms and signs. Essentially such tasks are accomplished by initiating remote functions in various modes of a communication system. The aim of the MEDAS protocol developed by our group is to propose a definition of such a high-level medical protocol and then to implement it. Our user-oriented protocol permits information exchange between heterogeneous systems. Modules and functions are defined. Message passing to and from a processor is realized using ports. The protocol sequence of every communication request is described. The relation of ports to the ISO model is specified. First experiences in a network for a medical school are reported.

Proton Therapy for Craniopharyngioma - An Early Report from a Single European Centre

AIMS

Proton beam therapy (PBT) is being increasingly used for craniopharyngioma. We describe our early outcome of patients treated with PBT.

MATERIALS AND METHODS

Between August 2013 and July 2016, 18 patients with craniopharyngiomas were treated with 54 Cobalt Gray Equivalent (CGE) in 30 fractions over 6 weeks at our centre. The early outcome of 16 patients included in a registry study was analysed. Radiological response was assessed by RECIST criteria and the disease- and treatment-related toxicities were scored according to the CTCAE 4.0.

RESULTS

All patients are alive at a median follow-up of 32.6 months (range 9.2-70.6 months) from initial diagnosis. The median age at PBT was 10.2 years (range 5.4-46.9 years). One patient progressed 8.7 months after PBT and subsequently had complete resection of the tumour. At a median follow-up of 18.4 months after PBT, five patients remained in complete remission, four in partial remission and seven with stable disease. The most common adverse effects during PBT were grade 1 (cutaneous in seven patients and fatigue in six patients). There were no treatment-related grade 3 toxicities.

CONCLUSIONS

Our early results are encouraging and comparable with the limited literature on PBT for craniopharyngioma.

Registration of Biplane Angiography and Intravascular Ultrasound for 3D Vessel Reconstruction

Abstract: If planned and applied correctly, intra-vascular brachytherapy (IVB) can significantly reduce the risk of restenosis after interventional treatment of stenotic arteries.

Objectives: In order to facilitate computer-based IVB planning, a three-dimensional reconstruction of the stenotic artery based on intravascular ultrasound (IVUS) sequences is desirable.

Methods: To attain a 3D reconstruction, the frames of the IVUS sequence are properly aligned in space and completed with additional intermediate frames generated by interpolation. The alignment procedure uses additional information that is obtained from biplane X-ray angiography performed simultaneously during the capturing of the IVUS sequence. After IVUS images and biplane angiography data are acquired from the patient, the vessel-wall borders and the IVUS catheter are detected by an active contour algorithm. Next, the twist between adjacent IVUS frames is determined by a sequential triangulation method combined with stochastic analysis.

Results: The above procedure results in a 3D volume-model of the vessel, which also contains information from the IVUS modality. This data is sufficient for computer-based intravascular brachytherapy planning.

Conclusion: The proposed methodology can be used to improve the current state-of-the-art IVB treatment planning by enabling computerized dosage computations on a highly accurate 3D model.

Health Information Search to Deal with the Exploding Amount of Health Information Produced

Objectives: This focus theme deals with the various aspects of health information search that are necessary to cope with the challenges of an increasing amount and complexity of medical information currently produced.

Methods: This editorial reviews the main challenges of health information search and summarizes the five papers of this focus theme.

Results and Conclusions: The five papers of the focus theme cover a large part of the current challenges in health information search such as coding standards, information extraction from complex data, user requirements analysis, multimedia data analysis and the access to big data. Several future challenges are identified such as the combination of visual and textual data for information search and the difficulty to scale when analyzing big data.

Multi-GEM Detectors in High Particle Fluxes

Gaseous Electron Multipliers (GEM) are well known for stable operation at high particle fluxes. We present a study of the intrinsic limits of GEMdetectors when exposed to very high particle fluxes of the order of MHz/mm2. We give an interpretation to the variations of the effective gain, which, as a function of the particle flux, first increases and then decreases. We also discuss the reduction of the ion back-flow with increasing flux. We present measurements and simulations of a triple GEM detector, describing its behaviour in terms of accumulation of positive ions that results in changes of the transfer fields and the amplification fields. The behaviour is expected to be common to all multi-stage amplification devices where the efficiency of transferring the electrons from one stage to the next one is not 100%.