Energy-dispersive X-ray micro Laue diffraction on a bent gold nanowire

This article reports on energy-dispersive micro Laue (µLaue) diffraction of an individual gold nanowire that was mechanically deformed in three-point bending geometry using an atomic force microscope. The nanowire deformation was investigated by scanning the focused polychromatic X-ray beam along the nanowire and recording µLaue diffraction patterns using an energy-sensitive pnCCD detector that permits measurement of the angular positions of the Laue spots and the energies of the diffracted X-rays simultaneously. The plastic deformation of the nanowire was shown by a bending of up to 3.0 ± 0.1°, a torsion of up to 0.3 ± 0.1° and a maximum deformation depth of 80 ± 5 nm close to the position where the mechanical load was applied. In addition, extended Laue spots in the vicinity of one of the clamping points indicated the storage of geometrically necessary dislocations with a density of 7.5 × 1013 m-2. While µLaue diffraction with a non-energy-sensitive detector only gives access to the deviatoric strain, the energy sensitivity of the employed pnCCD offers absolute strain measurements with a resolution of 1%. Here, the residual strain after complete unloading of the nanowire amounted to maximum tensile and compressive strains of the order of +1.2 and -3%, which is comparable to the actual resolution limit. The combination of white-beam µLaue diffraction using an energy-sensitive pixel detector with nano-mechanical testing opens up new possibilities for the study of mechanical behavior at the nanoscale.

Normal Load and Counter Body Size Influence the Initiation of Microstructural Discontinuities in Copper during Sliding

Near the interface of two contacting metallic bodies in relative motion, the microstructure changes. This modified microstructure leads to changes in material properties and thereby influences the tribological behavior of the entire contact. Tribological properties such as the friction coefficient and wear rate are controlled by the microstructure, while the elementary mechanisms for microstructural changes are not sufficiently understood. In this paper, the influence of the normal load and the size of the counter body on the initiation of a tribologically induced microstructure in copper after a single sliding pass is revealed. A systematic variation in the normal load and sphere diameter resulted in maximum Hertzian contact pressures between 530 MPa and 1953 MPa. Scanning electron microscopy, focused ion beam, and transmission electron microscopy were used to probe the subsurface deformation. Irrespective of the normal load and the sphere diameter, a sharp line-like feature consisting of dislocations, the so-called dislocation trace line, was identified in the subsurface area at depths between 100 nm and 400 nm. For normal loads below 6.75 N, dislocation features are formed below this line. For higher normal loads, the microstructure evolution directly underneath the surface is mainly confined to the area between the sample surface and the dislocation trace line, which itself is located at increasing depth. Transmission Kikuchi diffraction and transmission electron microscopy demonstrate that the misorientation is predominantly concentrated at the dislocation trace line. The results disclose a material rotation around axes roughly parallel to the transverse direction. This study demonstrates the generality of the trace line phenomena over a wide range of loads and contact pressures and the complexity of subsurface processes under a sliding contact and provides the basis for modeling the early stages in the microstructure evolution.

Matter-wave interference of a native polypeptide

The de Broglie wave nature of matter is a paradigmatic example of quantum physics and it has been exploited in precision measurements of forces and fundamental constants. However, matter-wave interferometry has remained an outstanding challenge for natural polypeptides, building blocks of life, which are fragile and difficult to handle. Here, we demonstrate the wave nature of gramicidin, a natural antibiotic composed of 15 amino acids. Its center of mass is delocalized over more than 20 times the molecular size in our time-domain Talbot-Lau interferometer. We compare the observed interference fringes with a model that includes both a rigorous treatment of the peptide’s quantum wave nature as well as a quantum chemical assessment of its optical properties to distinguish our result from classical predictions. The realization of quantum optics with this prototypical biomolecule paves the way for quantum-assisted measurements on a large class of biologically relevant molecules.

Matter-wave interferometry of complex molecules is challenging due to difficulties in preparing and detecting molecular beams. Here the authors demonstrate quantum behavior of a polypeptide using matter-wave interference in an all-optical time-domain Talbot-Lau interferometer.

Ionic conductivity of melt-frozen LiBH4 films

The fast Li conductivity of LiBH₄ envisages its use in all-solid-state batteries. Powders are commonly applied. But here, we study the formation of dense micrometer films by melting, spinning and subsequent solidifying. Characterized by electron microscopy, and spectroscopy (EDX/XPS/impedance), a reversible phase transformation is confirmed as well as a maximum conductivity of 10³ S cm⁻¹.

LiBH₄ melt-frozen film as solid state electrolyte.

Assessment of Bleeding for the Evaluation of Therapeutic Preparations in Small Animal Models of Antibody-Induced Hemophilia and von Willebrand Disease

Three small animal models of bleeding are described and used to evaluate the effects of preparations intended for therapy of human bleeding disorders. We modified techniques for the assessment of bleeding to be able to reproducibly quantify blood loss and rate of blood flow in addition to the measurement of bleeding time.

Temporary hemophilia was induced in a rabbit model by injection of high titer human inhibitor plasma [>1000 Bethesda units (BU)/ml]. A decrease in rabbit FVIII from normal values to below the limit of detection was observed within 30 min, cuticle bleeding time changed from normal (approx. 10 min) to steady state bleeding (>30 min), and the rate of blood flow increased from 4 to >30 µl blood/min. Infusion of an activated prothrombin complex concentrate (FEIBA STIM4, Immuno) at doses between 75 and 150 U/kg normalized the rate of blood flow, while infusion of FVIII/vWF concentrate resulted in partial correction. Administration of FVIIa, both recombinant and plasma-derived, failed to correct bleeding, however. In an analogous murine model, FVIII/ vWF inhibitor plasma was obtained by immunizing goats with a purified human FVIII/vWF complex. This plasma cross-reacted with mouse vWF in vitro. Injection of the anti-FVIII/vWF inhibitor plasma into mice caused a decrease in vWF antigen, in some animals with a complete loss of vWF multimers comparable to severe von Willebrand disease. A specific anti-vWF inhibitor plasma obtained by immunization of goats with recombinant vWF was used in a further murine model, resulting in a gradual but substantial decrease in FVIII as well as in intensive bleeding. The infusion of a FVIII/vWF concentrate (IMMUNATE, IMMUNO) normalized the rate of blood flow in both murine models. The same assessment methods were used to characterize bleeding in a natural mouse model of von Willebrand disease (strain RIIIS/J). The use of quantitative techniques of assessment of blood loss and rate of blood flow appears to be a helpful tool for characterizing hemorrhagic situations and evaluating the capacity of therapeutic preparations to correct hemostatic defects.

In situ Bragg coherent X-ray diffraction during tensile testing of an individual Au nanowire

Systematic tensile tests were performed on single defect-free 〈110〉 Au nanowires grown by physical vapor deposition while simultaneously recording three-dimensional Bragg peaks using coherent X-rays. The trajectory of three-dimensional Bragg peaks in reciprocal space during tensile testing allowed for measurements of the evolution of strains and rotations of the nanowire, thus sensitively uncovering the full deformation geometry of the nanowire. The transition from elastic to plastic deformation is accompanied by rotations of the nanowire as quantified by analysis of the motion of Bragg peaks, showing the importance of boundary conditions in interpreting nanoscale mechanical deformations.

Serum Vitamin E Levels in Patients with Chronic Renal Failure

27 patients with chronic renal failure, 21 patients on chronic intermittend dialysis treatment and 27 healthy controls were tested for serum level of vitamin E estimated spectrophotometrically. Both patient groups had significant higher mean values (12.1 ± 1.2 and 7.2 ± 0.8 μg/ml respectively) in comparison with normal controls (4.6 ± 0.7 μg/ml). No correlation was found to serum creatinine, hematologic values, protein and lipoprotein concentration, nor to mode and duration of treatment regimes. Vitamin E was not extracted from blood throughout dialysis.

Under normal conditions of conservative or dialysis treatment of chronic renal failure patients vitamin E seems not to be a factor concerning uremic symptoms and there is no need for supplementation.

The PF4/PPBP/CXCL5 Gene Cluster Is Associated with Periodontitis

Periodontitis is a common dysbiotic inflammatory disease with an estimated heritability of 50%. Due to the limited sample size of available periodontitis cohorts and the underlying trait heterogeneity, genome-wide association studies (GWAS) of chronic periodontitis (CP) have been unsuccessful in discovering susceptibility factors. A strategy that combines agnostic GWAS with a well-powered candidate-gene approach has the potential to discover novel loci. We combined RNA-seq data from gingival tissues with quantitative trait loci (QTLs) that were identified in a F₂-cross of mice resistant and susceptible to infection with oral bacterial pathogens. Four genes, which were located within the mapped QTLs, showed differential expression. The chromosomal regions across the human orthologous were interrogated for putative periodontitis-associated variants using existing GWAS data from a German case-control sample of aggressive periodontitis (AgP; 651 cases, 4,001 controls), the most severe and early onset form of periodontitis. Two haplotype blocks, one upstream to the coding region of UGT2A1 (rs146712414, P = 9.1 × 10^-5; odds ratio [OR], 1.34; 95% confidence interval [CI], 1.16-1.56) and one downstream of the genes PF4/PPBP/CXCL5 (rs1595009, P = 1.3 × 10^-4; OR, 1.32; 95% CI, 1.15-1.52), were associated with AgP. The association of rs1595009 was validated in an independent cohort of CP of European Americans (1,961 cases and 1,864 controls; P = 0.03; OR, 1.45; 95% CI, 1.01-1.29). This association was further replicated in another sample of 399 German CP cases (disease onset <60 y of age) and 1,633 controls ( P = 0.03; OR, 1.75; 95% CI, 1.06-2.90). The combined estimates of association from all samples were P = 2.9 × 10^-5 (OR, 1.2; 95% CI, 1.1-1.3). This study shows the strength of combining QTL mapping and RNA-Seq data from a mouse model with association studies in human case-control samples to identify genetic risk variants of periodontitis.

X-ray Microanalysis of Elements in the Masticatory Muscle after Paresis of the Right Masseter

Muscle activity and function appear to be related to ionic concentrations in the muscle. We investigated whether muscle paresis induced by injection of Botulinum toxin A (Botox) in 16-week-old pigs over a 56-day period is associated with ionic changes in the affected muscles. Tissue samples were taken from the masseter, temporalis, medial pterygoid, and geniohyoid muscles by a standardized method and used for energy-dispersive x-ray microanalysis in an environmental scanning electron microscope. The largest increase in Na+ was measured in the right and left sides of the masseter muscle in treated animals. Additionally, a significant elevation of Na+ was measured in the anterior part of the temporalis muscle and in the pterygoid muscle (P < 0.05). In temporalis and pterygoid muscles, an increase in sulfur in both sides of treated pigs’ heads was observed. Botox® has an indirect impact on ion concentrations, resulting in changes in muscle functional capacity and adaptive compensation of paretic muscle function by other muscles.

KB scanning of X-ray beam for Laue microdiffraction on accelero-phobic samples: application to in situ mechanically loaded nanowires

A mapping technique has been developed where a sub-micrometer focused polychromatic X-ray beam is scanned across a stationary sample instead of scanning the sample in front of the X-ray microbeam. This method is applied to a gold nanowire during its mechanical loading using the tip of an atomic force microscope. During the loading process, such a sample is `accelero-phobic', i.e. the sample scanning stages must not to be moved to avoid parasitic additional load. Without beam scanning, only one single position within the sample can be probed during the test. The probed material point may even change because of drifts or movements induced by the test itself. The new scanning approach facilitates the in situ mapping of the entire wire giving access to the evolution of the wire shape as well as to the boundary conditions. This novel scanning technique opens promising perspectives for studies where sample motion is forbidden because of the sample environment.

[Traumatic aortic rupture and concomitant type B aortic dissection after skiing accident]

The occurrence of aortic dissections after deceleration trauma is commonplace but aortic injuries after blunt trauma are extremely rare complications. We report a case of an acute aortic rupture accompanied by a type B dissection after a skiing accident with blunt thoracic trauma and renal contusion. The leading symptom was the onset of hematuria 12 h later. The computed tomography (CT) angiography permitted the exact diagnosis and the patient was transferred for acute thoracic endovascular aortic repair. This regimen resulted in the patient achieving a stable condition and potentially harmful complications could be avoided.

Identification of germline susceptibility loci in ETV6-RUNX1-rearranged childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a malignant disease of the white blood cells. The etiology of ALL is believed to be multifactorial and likely to involve an interplay of environmental and genetic variables. We performed a genome-wide association study of 355 750 single-nucleotide polymorphisms (SNPs) in 474 controls and 419 childhood ALL cases characterized by a t(12;21)(p13;q22) - the most common chromosomal translocation observed in childhood ALL - which leads to an ETV6-RUNX1 gene fusion. The eight most strongly associated SNPs were followed-up in 951 ETV6-RUNX1-positive cases and 3061 controls from Germany/Austria and Italy, respectively. We identified a novel, genome-wide significant risk locus at 3q28 (TP63, rs17505102, P(CMH)=8.94 × 10(-9), OR=0.65). The separate analysis of the combined German/Austrian sample only, revealed additional genome-wide significant associations at 11q11 (OR8U8, rs1945213, P=9.14 × 10(-11), OR=0.69) and 8p21.3 (near INTS10, rs920590, P=6.12 × 10(-9), OR=1.36). These associations and another association at 11p11.2 (PTPRJ, rs3942852, P=4.95 × 10(-7), OR=0.72) remained significant in the German/Austrian replication panel after correction for multiple testing. Our findings demonstrate that germline genetic variation can specifically contribute to the risk of ETV6-RUNX1-positive childhood ALL. The identification of TP63 and PTPRJ as susceptibility genes emphasize the role of the TP53 gene family and the importance of proteins regulating cellular processes in connection with tumorigenesis.

Incontinetia pigmenti-related myopathy or unsolved "double trouble"?

Incontinentia pigmenti is an X-linked dominant or sporadic multisystemic disorder with involvement of skin, eyes and central nervous system which results from mutations in the gene for NF-kappaB essential modulator (NEMO). We report on a patient with genetically confirmed Bloch-Sulzberger syndrome, who presented with a progressive myopathy and cardiomyopathy. Genetic analyses revealed an intragenic deletion (Intron3 and Exon10) of the NEMO/IKKgamma/IKKAP/IKBKG gene. Further complete sequencing of genes encoding for desmin, lamin A/C, emerin, and FHL1 showed no evidence of pathogenic mutations. A pathological expansion of CCTG repeats of the ZNF9 gene (PROMM) was ruled out by PCR amplification analysis. MLPA-analysis showed no evidence for duplications or deletions of the dystrophin gene. This report highlights the unusual combination of a genetically confirmed incontinentia pigmenti and a proximal myopathy and dilatative cardiomyopathy of unknown origin. We discuss that the striated muscle involvement (i) might be based on the observed intragenic deletion of the NEMO gene, or (ii) on an additional gene defect leading to an adult onset myopathy. Further studies on neuromuscular involvement in patients with incontinentia pigmenti are needed to clarify this issue.