bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlation between fatigue crack growth rate and striation spacing in XZM
Authors: DeTurk Scott M. , Cunningham Roy J.
Published: June 2020

Much information can be learned from the fracture surface of a metallic component. At a microscopic level, the relationship between a fatigue fracture surface and the rate at which the crack propagated through the material is of particular interest. At certain growth rates, a fatigue fracture surface is comprised of striations which are the results of a cyclical loading being applied to a component. When evaluating a fatigue fracture surface to determine crack growth rates, a Transmission Electron Microscope (TEM) is employed to observe the striations. However, the following question arises, “Does one fatigue striation equal one load cycle”? In previously published literature, the relationship of one striation being equal to one load cycle has been confirmed for various aluminum alloys. The test data presented herein is for steel, i.e., a High Hot Hardness (HHH) gear material utilized in helicopter transmissions. The correlation of one striation being equal to one load cycle was obtained and documented during a fatigue crack growth test of X2M gear steel. A prime use of this data would be in the evaluation of a fatigue fracture surface to determine the initiation time and propagation rate for a service related failure.
Applications of SEM/EDXA in cement clinker investigation
Authors: Tagnit-Hamou Arezki , Sarkar Shondeep L.
Published: June 2020

All the desired properties of cement primarily depend on the physicochemical characteristics of clinker from which the cement is produced. The mineralogical composition of the clinker forms the most important parameter influencing these properties.

Optical microscopy provides reasonably accurate information pertaining to the thermal history of the clinker, while XRDA still remains the proven method of phase identification, and bulk chemical composition of the clinker can be readily obtained from XRFA. Nevertheless, all these microanalytical techniques are somewhat limited in their applications, and SEM/EDXA combination fills this gap uniquely by virtue of its high resolution imaging capability and possibility of instantaneous chemical analysis of individual phases.

Inhomogeneities and impurities in the raw meal, influence of kiln conditions such as sintering and cooling rate being directly related to the microstructure can be effectively determined by SEM/EDXA. In addition, several physical characteristics of cement, such as rhcology, grindability and hydraulicity also depend on the clinker microstructure.
Imaging of chemical reactions in Pt-Sn thin films
Authors: Dufner D. C.
Published: June 2020

The general goal of this research is to clarify mechanisms of solid state reactions at the atomic level as a step in the rationalization of macroscopic reaction behavior in solids. A study of chemical reactions occurring as interdiffusion or other transport processes proceed in thin films can be made by means of HRTEM. In this research, chemical changes occurring near interfaces in solid specimens which are very thin (<20nm) in at least one direction are studied.

As previously studied with the Au-Sn system, the chemical reactions in the Pt-Sn system are being observed in this investigation. Thin film samples were prepared by the two-film method introduced by Shiojiri. Several hundred nanometers of Pt were vacuum deposited onto holey carbon films mounted on TEM grids. Sn films with an average thickness of 20nm were created by evaporation at rates of 1.5-3.0 nm/sec onto air-cleaved KBr substrates. The Sn films were wet-stripped and collected on the holey Pt grids. This combination of Pt and Sn films formed a solid-solid interface through which interdiffusion of Pt and Sn can take place and allowed for compositional and structural changes to be observed in the TEM. In some preparations, islands of Pt were evaporated directly onto the Sn films. TEM was carried out on the Philips 400T at 120kV or on the JEOL 2000FX at the Texas Center for Superconductivity at the University of Houston.
A symmetry-violating precipitation process induced under irradiation
Authors: Kesternich W.
Published: June 2020

TiC precipitates in austenitic steel have been found to reveal a very unusual precipitation behaviour /l,2/. As a consequence, nucleation initiated by dislocation recovery or growth induced during recrystallization can be used to create predesired modifications of the microstructure and the mechanical properties /2—3/. The extraordinary high resistance to precipitate growth and coarsening /l/ appears to be the key property in these applications and also appears to be the origin for a unique precipitate phenomenon which was observed in the present irradiation experiment.

A 1.4970 type steel (15Ni—15Cr austenite, containing Ti and C) was neutron irradiated at 845 K to a dose of 2.6 x 1025 m-2 thermal neutrons (helium production) and 3.0 x 1025 fast neutrons (1.5dpa). Before irradiation the steel was solution annealed leaving about half of the Ti and C in supersaturated solution. Defect cascades introduced by the neutron irradiation acted as nucleation centres for MC (M=Ti, Nb, Mo...) precipitates as has already previously been demonstrated in Ti- and Nb-stabilized steels /4/. In addition to the common, irregularly shaped MC precipitates, however, two further precipitate variants were created during the present high temperature neutron irradiation. One precipitate variant was star—shaped with cube—on—cube orientation relationship with the matrix. The other variant was nail—shaped. Analysis of crystal structure and orientation relationship of the nail—shaped precipitates was made difficult by their small shape and by double diffraction effects. Fig. la shows a (001) SAD pattern of matrix (heavy spots) and precipitates (fine spots). The quadruplets in the vicinity of <110> are created from the new precipitates. Each of the four quadruplet spots actually consists of three closely spaced spots (Fig. lb), and the eight precipitate spots surrounding each of the matrix spots in Fig. la each consist of two spots. After the double diffraction effects had been assigned (schematic in Fig. lb for example) they were reduced by specified specimen tilting around two axes (Fig. lc). It was found by combined dark- field and diffraction analyses that all diffraction spots originated from TiC precipitates and that four orientation variants of the TiC precipitates were distinguishable. They are imaged in Fig. 1d in bright field and in Fig. 2 in four corresponding dark field images by using reflections 0 to 3 of Fig. lc. 0 shows precipitates of the common cube—on— cube orientation relationship. 1 to 3 shows nail—shaped precipitates with nail axes pointing along the three <110> directions. The diffraction analysis revealed that the lattice of the nail precipitates is rotated by 45 degrees around the nail axes from cube-on-cube orientation, thus giving rise to the three orientation variants.
The effect of radiation-induced segregation on void swelling in electron-irradiated austenitic Fe-Cr-Ni-Ti-P Alloy
Authors: Watanabe H. , Muroga T. , Yoshida N.
Published: June 2020

It has been reported that the void swelling in austenitic steels at higher temperatures is enhanced by a nickel depletion in matrix . The objective of the present study is to understand the effect of solute addition on void swelling, in association with microchemical changes, in austenitic steels during electron irradiation.

Four types of model alloys (Fe-16Cr-17Ni, Fe-16Cr-17Ni-0.25Ti, Fe- 16Cr-17Ni-0.1P, Fe-16Cr-17Ni-0.25Ti-0.IP) and JPCA-2 were used in this study. Irradiation and in-situ observation were carried out with 1.0 MeV electrons utilizing JEM-1000 of HVEM Lab. Kyushu Univ.

Fig. 1 shows the irradiation temperature dependence of nickel concentration in matrix after irradiated at 2 dpa. The ternary alloy and alloys containing phosphorus(or titanium) only show a strong nickel depletion in matrix due to nickel segregation to defect sinks. Our previous results about void swelling in these alloys showed that the temperature, where nickel depletion in matrix became prominent, corresponded to that of maxium void swelling. On the other hand, void swelling and the nickel depletion were not detected in Fe-16Cr-17Ni-0.25Ti-0.IP and JPCA-2.
“Cavity” formation in superplastically deformed aluminium alloys
Authors: Cziráki A. , Ková-csetényi E. , Torma T. , Turmezey T.
Published: June 2020

It is known that the formation of cavities during superplastic deformation can be correlated with the development of stress concentrations at irregularities along grain boundaries such as particles, ledges and triple points. In commercial aluminium alloys Al-Fe-Si particles or other coarse constituents may play an important role in cavity formation.

Cavity formation during superplastic deformation was studied by optical metallography and transmission scanning electron microscopic investigations on Al-Mg-Si and Al-Mg-Mn alloys. The structure of particles was characterized by selected area diffraction and X-ray micro analysis. The volume fraction of “voids” was determined on mechanically polished surface.

It was found by electron microscopy that strongly deformed regions are formed during superplastic forming at grain boundaries and around coarse particles.

According to electron diffraction measurements these areas consist of small micro crystallized regions. See Fig.l.

Comparing the volume fraction and morphology of cavities found by optical microscopy a good correlation was established between that of micro crystalline regions.
Structure of a new orthorhombic phase in NiTi: Mn shape memory alloys
Authors: Beyer Jenö , Tóth Lajos
Published: June 2020

The structural changes during reversible martensitic transformation of near-equiatomic NiTi alloys can best be studied in TEM at around room temperature. Ternary additions like Mn offer this possibility by suppressing the Ms temperature below RT. Besides the stable intermetallic phases (Ti2Ni, TiNi, TiNi3) several metastable phases with various crystallographic structures (rhombohedral, hexagonal, monoclinic, cubic) have also been reported to precipitate due to suitable annealing procedures.

TiNi:Mn samples with 0.9 and 1.3 at% Mn were arc melted in argon atmosphere and homogenized at 948 °C for 72 hours in high vacuum in an infrared furnace. After spark cutting slices of 0.2 mm, TEM specimens were prepared by electrochemical polishing with the twin-jet technique in methanol - perchloric acid electrolyte. The TEM study was carried out in a JEOL 200 CX analytical electron microscope.

In this paper a new intermetallic phase is reported which has been observed in both samples by TEM during the martensitic transformation process.
A HVEM study on the deformation microstructures of quartz in the fault rocks from a seismic fault zone in west china
Authors: Zhuoran Lin , Zhuen Yang , Chunping Zhou
Published: June 2020

Our work has been aimed at the exploratory observation and study on the intracrystalline submicron deformation structures of quartz in a series of deformed rocks occurred along the Fuyun fault zone in Xinjian, West China, which is a typical seismic one with strong activities since Cenozoic period, in connection with the corresponding works on seismology and structural petrology, using the ultra high voltage electron microscope (HVEM).

With the successful method of sample preparation by select area stripping from a petrographic microscopy section and ion thinning, and with the advantages of stronger penetration power and lower radiation damage of HVEM, our observation on the intracrystalline deformation microstructure has been made more reliable and productive.

In the light of dislocation theory and the experimental results of quartz deformation, up to hundred of HVEM micrographs have been analysed and summarized with reference to the current conceptual model of fault.
High-Resolution Lattice Images of Superconductors Observed at 4.2 K
Authors: Yoshida Hiroyuki , Yokota Yasuhiro , Hashimoto Hatsujiro , Iwatsuki Masashi , Harada Yoshiyasu
Published: June 2020

High resolution cryo electron microscopy has been applied to the observation of microstructures of A15-type and oxide superconductors. In order to study the relation between atomic structures and superconducting properties the atomic resolution observation at cryogenic temperatures seems to be important, especially for high Tc superconductors with perovskite structure whose coherent length along c axis is closed to the lattice spacings. High resolution lattice images were obtained using a superconducting cryo electron microscope JEM-2000 SCM operated at 160 KV. The microscope enable the specimen to keep at 4.2 K without thermal drift and vibration under ultra high vacuum. The magnetic field at the specimen position is 1.4 T when the electron microscope is operated at 160 kV.

Figure 1 shows a high resolution image of the electropolished thin crystal of Nb3(A10.77Ge0.23) (Tc=19 K). In the both sides of the grain boundary the (100) lattice fringes with 0.52 nm spacing of the A15 structure are clearly resolved. The high resolution images obtained for Nb3Sn superconductors gave the bright dots at the position of Nb atom chains along 001 direction as confirmed by the image contrast calculation.
HREM Study of the Plasticity in a Si Bicrystal
Authors: Thibault Jany , Luc Putaux Jean , Elkajbaji Mohamed
Published: June 2020

The Σ=9(122) <011> pure tilt silicon bicrystal has been deformed. The evolution of its structure under stress has been studied in details. It was shown /1,2,3,4,5/ that the deformation induced dislocations generally enter the grain boundary (GB) where they decompose into elementary GB dislocations (GBD'). GBD's react by glide and climb. The GB migrates when GBD's associated with step are moving along the interface. This leads to appreciable changes of the original GB structure whereas the misorientation angle between the two grains varies. This paper deals with the structure determination of all the defects involved in the previous transformation and of the different GB's structures encountered during the process. The HREM observations were performed on the JEOL 200CX (Cs=1.05mm) to avoid electron irradiation damage in silicon and the images were simulated using a dedicated computer.

i) Initial Σ=9 (122) GB (θ = 38.94°): the initial structure has been studied /6,7,8/. The main feature is the zig-zag stacking of the 7-5 atom rings (called M structural unit Jin the (122) common plane.In the following the stacking of the GB period will be described by the sequence M+M− (M+ is the mirror of M− with respect to the GB plane).
Electron Crystallographic Determination of the Structure of Bacteriorhodopsin
Authors: Henderson R. , Baldwin J.M. , Ceska T.A. , Beckman E. , Zemlin F. , Downing K. H.
Published: June 2020

The light driven proton pump bacteriorhodopsin (bR) occurs naturally as two-dimensional crystals. A three-dimensional density map of the structure, at near atomic resolution, has been obtained by studying the crystals using electron cryo-microscopy to obtain diffraction patterns and high resolution micrographs (1).

New methods have been developed for analysing micrographs from tilted specimens, incorporating the methods previously developed for untilted specimens that enable large areas to be analysed and corrected for distortions. Data from 72 images, from both tilted and untilted specimens, have been analysed to produce the phases of 2700 independent Fourier components of the structure. The amplitudes of these components have been accurately measured from 150 diffraction patterns. Together, these data represent about half of the full three-dimensional transform to 3.5 Å. The distribution of the data which is included in the map is shown in fig. 1. For specimen tilts up to around 20° the data is essentially complete. For higher tilts the data is more sparsely sampled, and is at present about half complete.
Development of 120KV Electron Microscope
Authors: Suzuki S. , Mori S. , Mizuno M. , Ichikawa R. , Honda T.
Published: June 2020

A new electron microscope (EM) of 120 kV has been developed. This EM is designed for biological study but it incorporates many new ideas as a new transmission electron microscope. The main features of this new electron microscope are as follows.

A. New Lens System and Control

The illumination lens and imaging lens system and these control methods have been improved in this EM. It has three illumination mode, which are the spot focus mode, the parallel focus mode and the α focus mode. In the parallel focus mode, the cross over point under the specimen is kept on an objective aperture, which is placed in the back focal plane. That makes it possible to set the small objective aperture such as 20 micron without field cut and any sacrifices of specimen tilting angle at very low magnification. The objective lens condition in the diffraction mode is depending on the imaging mode, which are MAG mode and LOW MAG mode. That means it has two diffraction mode, the objective lens is kept on in one mode and off in the other mode corresponding to the imaging mode, MAG and LOW MAG modes. So the beam position is kept exactly on the specified area on the specimen during the changeover between the imaging mode and diffraction mode.
Beyond One Angstrom
Authors: Crewe Albert. V.
Published: June 2020

I believe everyone would agree we have just about reached the limit of performance of today's electron microscopes. This is not to say that additional advances will not take place, because there is always one more drop of blood to squeeze out. But it is certainly becoming increasingly apparent that we can not expect more out of the magnetic lenses that we now have. I am sure that everyone who has ever been concerned with this problem has arrived at the same set of conclusions but it may help to set them down one more time.

The available resolution in electron microscopy is distressingly poor compared to the wavelength of the electrons. The culprit is always the objective lens. For low energy, say less than 5,000 volts, chromatic aberration is the offending element whereas at high voltages it is the spherical aberration coefficient which we must be concerned with. In both cases, there are some basic restrictions which apply. In the case of chromatic aberration it is always very closely equal with the focal length of the lens and for the spherical aberration coefficient the best we can do is about 1/4 or 1/2 the focal length.
Experimental Study on Correction of Spherical Aberration in Electro-Magnetic Round Lens
Authors: Chen Ergang , Mu Chongjun
Published: June 2020

As we know that the spherical aberration in a round electromagnetic lens can not be eliminated. Therefor,the correcting of such aberration is an important subject to improve the ultimate resolution of electron microscopes and the performance of other electron optical instruments, such as electron beam manufactureing machines, electron lithographic machine etc.

A combination of quadrupoles and octupoles which was proposed by Scherzer is a reasonable way to correct this aberration, but it has been proved practically unsuccessful. Crewe suggested that the sextu-pole elements could be used as a device to correct the 3rd order aberration of a round lens. Later he has showed that a system of two sextupoles with a round lens placed in the middle of it can acturely act as an electromagnetical concave lens if the focal length of this middle lens be settled to satisfy certain condition. Instead of taking terms of z7 in series solution of motion equation of electron in sextu-pole which Crewe had done, we took it up to z20to compute the amplitude r and slope r' of electron trajectory at each specific point z1 , z2 , z3, and z4along the optical axis. The results show that the action of sex-tupole-lens-sextupole system does act as an optical concave lens. It produces a negative spherical aberration. Differing from optical concave lens, in this system the negative aberration can be varied in a wide rang by adjusting the strength of sextupole k. Fig.2 shows a series of computed performances of electron beam near Gaussian image point while the strength of sextupole k=0 incase(a) and k1< k2in case (b) and (c). Evidently, this system does produce a negative spherical aberration while k is not zero.
CRYO-Electron Microscopy of Muscle and Muscular Componants
Authors: Lepault Jean , Delacroix Hervé , Erk Inge , Nicolas Gisèle , Ranck Jean-Luc
Published: June 2020

Cryo-electron microscopy of vitrified specimens is used to study biological objects in their native aqueous environment. Preparation artifacts are therefore minimized. In addition, due to the fast cryo-fixation associated with the vitrification process, cryo-electron microscopy may be used for dynamic structural investigations. To take full advantage of these possibilities, we are studying isolated muscular componants: actin and myosin.

We observed the polymerization process of actin filaments. When the ionic strength of a globular actin suspension (G-actin-ATP) is increased, actin polymerized and filamentous actin (F-actin) is formed. During the polymerization, ATP is hydrolyzed. Three chemical forms of F-actin are then successively formed: F-actin-ATP, F-actin-ADP-Pi and F-actin-ADP. F-actin visualized in the short time of the polymerization process (F-actin-ATP; F-actin-ADP-Pi is characterized by a disordered polymer. At steady state (F-actin-ADP), F-actin appears more ordered and has its well known appearence of a helical polymer. These results show that actin has different structures which may play a role in muscular contraction.
Performance Evaluation of a Novel Type of Low-Energy Electron Microscope
Authors: Senftinger Bertholdand , Liebl Helmut
Published: June 2020

During the last few years the investigation of clean and adsorbate-covered solid surfaces as well as thin-film growth and molecular dynamics have given rise to a constant demand for high-resolution imaging microscopy with reflected and diffracted low energy electrons as well as photo-electrons. A recent successful implementation of a UHV low-energy electron microscope by Bauer and Telieps encouraged us to construct such a low energy electron microscope (LEEM) for high-resolution imaging incorporating several novel design features, which is described more detailed elsewhere.

The constraint of high field strength at the surface required to keep the aberrations caused by the accelerating field small and high UV photon intensity to get an improved signal-to-noise ratio for photoemission led to the design of a tetrode emission lens system capable of also focusing the UV light at the surface through an integrated Schwarzschild-type objective. Fig. 1 shows an axial section of the emission lens in the LEEM with sample (28) and part of the sample holder (29). The integrated mirror objective (50a, 50b) is used for visual in situ microscopic observation of the sample as well as for UV illumination. The electron optical components and the sample with accelerating field followed by an einzel lens form a tetrode system. In order to keep the field strength high, the sample is separated from the first element of the einzel lens by only 1.6 mm. With a numerical aperture of 0.5 for the Schwarzschild objective the orifice in the first element of the einzel lens has to be about 3.0 mm in diameter. Considering the much smaller distance to the sample one can expect intense distortions of the accelerating field in front of the sample. Because the achievable lateral resolution depends mainly on the quality of the first imaging step, careful investigation of the aberrations caused by the emission lens system had to be done in order to avoid sacrificing high lateral resolution for larger numerical aperture.
A Simulation of Electron Scattering in Metals and its Application for Scanning Electron Microscopy
Authors: Kotera Masatoshi , Ijichi Ryoji , Fujiwara Takafumi , Suga Hiroshi , Wittry David B.
Published: June 2020

In a recent research, the scanning electron microscope(SEM) has been shown to provide spatial resolution of less than 0.5nm. With the knowledge of the ultimate resolution or the factor which controls the resolution, it is possible to optimize the specimen preparation method and the choice of various electron beam parameters (eg. acceleration voltage etc.) For a precise discussion of the SEM image, it is necessary to take into account not only the signal (electron) production and the propagation in a specimen and its emission from the surface, but also electron trajectories in vacuum toward the detector. However, electron scattering process in the specimen does not depend on the detection system, and the resolution is mainly attributed to the spatial distribution of the electron emission from the specimen surface. Here, we focused on the electron scattering mechanisms in metals and developed a Monte Carlo simulation model of electron trajectories. Also, this simulation is applied to evaluate a compositional contrast in the SEM.

In the present study electron interactions with atomic potential, inner-shell electrons, conduction electrons are taken into account. Cross sections calculated by the present model are shown in Fig.1 for [l]elastic scattering, [2]inner-shell (1s, 2s, 2p for Al) electron ionization, [3]conduction electron ionization through non-radiative plasmon decay, and [4] stable plasmon excitation in the conduction band electrons for Al. For the elastic scattering, the Mott cross section is used. For inner-shell electron ionizations by an electron collision, the Gryzinski equation is used. In order to express the plasmon-electron interaction in a free electron gas at the conduction band, the Lindhard treatment is used. This treatment is based on the random phase approximation in the dielectric response function of metals. The cross section is shown in a unit of the inverse mean free path. The cross sections for conduction electron ionization and the plasmon excitation agree with the data of Tung, Ashley, and Ritchie. Cross sections for inner-shell electron ionization, which Tung et al. have derived using the generalized oscillator strength, are also shown in Fig.1 for a comparison.
EDS Image Classification by Projection after Partitioning
Authors: King L. , Browning R. , Paque J. M. , Pianetta P.
Published: June 2020

In the analysis of multispectral x-ray dispersive images of geological materials, it is found that the large number of mineral phases typically present, leads to a large number of significant principal component images. This large dimensionality produces difficulties in graphically presenting the data, and interactively partitioning die image. A further problem is in the nature of the mineral phase distributions. Some phases will be well separated, in at least one projection direction, and other phases are continuous mixtures, with two or more end points. Both types of mineral phase distributions can be found intimately mixed in a geological sample. The very different types of these distributions implies that routines for searching n-space for clustering will have difficulty producing a good projection of the continuous mixture phase. Also for this reason it is difficult to see how alternative projection techniques can give a meaningful weight to a mixed phase in the presence of well separated components.

Here we describe a multi-step image analysis which circumvents the above problem, and promises to be a convenient, and relatively simple extension of principal component analysis (PCA). The analysis method relies on the fact that there is very often, some clear separation of an image after PCA, and that this clear separation can be readily observed in the first few principal component images. Thus the information in the first few principal component scatter diagrams can be partitioned interactively into regions that are well separated from each other, but may be individually complex. PCA can then be applied to the data subsets, and the process can be repeated until a meaningful projection of the data can be viewed in a low dimensional scatter diagram. The real image can then be formed using either density or false color imaging, depending on which is appropriate for the subset alone. The method is thus finding projections after partitioning.
Advantages of using Digitized Micrographs for Serial-Section 3-D Reconstruction
Authors: Marko Michael , Leith ArDean , Parsons Donald
Published: June 2020

Digitized micrographs provide advantages in making 3-D reconstructions from serial sections. The use of image enhancement, magnification zoom, synthetic stereo, and rapid interactive review of the entire set of serial sections improves the accuracy and ease of reconstruction. We use the STERECON system for tracing contours from serial sections, storing the contour data, editing, and displaying the 3-D reconstructions. STERECON has options for stereoscopic input and display. Either digitized or conventional photographic images can be used with the system.

Structures can be traced more easily in digitally-enhanced images. Digital image enhancement techniques have been extensively developed in the medical imaging field, and many of the same techniques are also useful for microscopy. Among the most difficult images to deal with photographically are those which have uneven exposure or a large variation in density. Since photographic film has a wider dynamic range than paper, it is difficult to bring out details in both light and dark areas of the image on the same print. Dodging results in loss of contrast which cannot always be recovered by using higher contrast grades of paper. Routine digital techniques can easily deal with this situation. In addition, nearly invisible, very-low-contrast structures in the image can be made distinct. Most importantly, edges of structures can be enhanced for more accurate tracing of contours. The extension of this is automatic contouring, which is used with varying degrees of success, depending on the complexity of the image.
Interaction of Proteins with Functional Monolayers: Recognition, 2D-Crystallization and Function
Authors: Ahlers M. , Darst S.A. , Grainger D.W. , Kornberg R.D. , Müller W. , Reichert A. , Ringsdorf H. , Rump E. , Salesse C.
Published: June 2020

The interaction of molecular self organization and molecular recognition leads to the formation of functional supramolecular systems (see Figure 1). They combine order and mobility and their function is based on their organization.’ These fascinating phenomena - and the living cell is only the most perfect example - can help to mimic biomembrane processes as well as to develop new materials. The interaction of proteins with biomembranes is of fundamental relevance in many fields of biochemistry and medicine. Model biomembranes offer the possibility to simulate such naturally occuring processes. The monolayer technique in particular has proven to be an ideal tool to investigate the interaction of water soluble proteins with model membranes. Unspecific adsorption of proteins at charged lipid monolayers, specific recognition of ligand molecules by proteins and enzyme binding followed by enzyme action may lead to highly oriented protein domains and even to 2D-crystallization (see Figure 2).

Due to its high binding constant (Kd = 10−15 mol-1), the biotin/streptavidin system is an ideal tool to investigate the specific interaction between a membrane incorporated receptor and a protein. Streptavidin is a protein which comprises four identical subunits, each binding one biotin molecule, and is well known from affinity chromatography. Biotin lipids with biotinylated headgroups have been synthesized to act as the membrane-incorporated receptors. Injection of fluorescent-labeled streptavidin underneath a monolayer of biotin lipids in the gas-analogue state results in formation of regular H-shaped optically anisotropic two-dimensional streptavidin domains. The crystallinity of these two-dimensional domains was determined by electron crystallography, revealing diffraction patterns with a resolution of 1.5 nm. The match of the electron density map thus obtained and the X-ray crystal structure of streptavidin is remarkably close, showing that two binding sites are still free and face away from the lipid layer, exposed to the aqueous solution. This offers the possibility of building up protein multilayer structures - even a second crystalline protein layer is imaginable, using the first streptavidin layer as a matrix for the binding of other biotinylated proteins.
Dosimetric evaluation of whole-pelvis radiation therapy of prostate cancers: clinical experience
Authors: Osei Ernest , Mansoor Hafsa , Darko Johnson , Osei Beverley , Fleming Katrina , Rachakonda Ramana
Published: June 2020

Background:

The standard treatment modalities for prostate cancer include surgery, chemotherapy, hormonal therapy and radiation therapy or any combination depending on the stage of the tumour. Radiation therapy is a common and effective treatment modality for low-intermediate-risk patients with localised prostate cancer, to treat the intact prostate and seminal vesicles or prostate bed post prostatectomy. However, for high-risk patients with lymph node involvement, treatment with radiation will usually include treatment of the whole pelvis to cover the prostate and seminal vesicles or prostate bed and the pelvic lymph nodes followed by a boost delivery dose to the prostate and seminal vesicles or prostate bed.

Materials and Methods:

We retrospectively analysed the treatment plans for 179 prostate cancer patients treated at the cancer centre with the volumetric-modulated arc therapy (VMAT) technique via RapidArc using 6 MV photon beam. Patients were either treated with a total prescription dose of 78 Gy in 39 fractions for patients with intact prostate or 66 Gy in 33 fractions for post prostatectomy patients.

Results:

There were 114 (64%) patients treated with 78 Gy/39 and 65 (36%) treated with 66 Gy/34. The mean homogeneity index (HI), conformity index (CI) and uniformity index (UI) for the PTV-primary of patients treated with 78 Gy are 0.06 ± 0.01, 1.04 ± 0.01 and 0.99 ± 0.01, respectively, and the corresponding mean values for patients treated with 66 Gy are 0.06 ± 0.02, 1.05 ± 0.01 and 0.99 ± 0.01, respectively. The mean PTV-primary V95%, V100% and V105% are 99.5 ± 0.5%, 78.8 ± 12.2% and 0.1 ± 0.5%, respectively, for patients treated with 78 Gy and 99.3 ± 0.9%, 78.1 ± 10.6% and 0.1 ± 0.4%, respectively, for patients treated with 66 Gy. The rectal V50Gy, V65Gy, V66.6Gy, V70Gy, V75Gy and V80Gy are 26.8 ± 9.1%, 14.2 ± 5.3%, 13.1 ± 5.0%, 10.8 ± 4.3%, 6.9 ± 3.1% and 0.1 ± 0.1%, respectively, for patients treated with 78 Gy and 33.7 ± 8.4%, 14.1 ± 4.5%, 6.7 ± 4.5%, 0.0 ± 0.2%, 0.0% and 0.0%, respectively, for patients treated with 66 Gy.

Conclusion:

The use of VMAT technique for radiation therapy of high-risk prostate cancer patients is an efficient and reliable method for achieving superior dose conformity, uniformity and homogeneity to the PTV and minimal doses to the organs at risk. Results from this study provide the basis for the development and implementation of consistent treatment criteria in radiotherapy programs, have the potential to establish an evaluation process to define a consistent, standardised and transparent treatment path for all patients that reduces significant variations in the acceptability of treatment plans and potentially improve patient standard of care.
Inklusion – Forderungen und Umsetzungsmöglichkeiten im deutschen Schulsystem
Authors: Seitz Stefan
Published: June 2020

Zusammenfassung. Schulen in Deutschland haben aufgrund internationaler Vereinbarungen seit zehn Jahren den Auftrag, in ihren Klassen auf Wunsch der Eltern Schüler_innen, ohne und mit Beeinträchtigungen gemeinsam zu beschulen und zu fördern. Dies erfordert von allen Beteiligten ein grundlegendes Umdenken in ihrem beruflichen Selbstverständnis sowie neuartige Kompetenzen, um dieser gemischten Schülerklientel gerecht zu werden.
Estimation of Sea Ice Production in the Bering Sea From AMSR‐E and AMSR2 Data, With Special Emphasis on the Anadyr Polynya
Authors: Ohshima Kay I. , Tamaru Naoya , Kashiwase Haruhiko , Nihashi Sohey , Nakata Kazuki , Iwamoto Katsushi
Published: June 2020

We created, for the first time, a map of sea ice production in the Bering Sea, based on thin‐ice thickness data from the Advanced Microwave Scanning Radiometers (AMSR‐E and AMSR2) with a heat flux calculation. We used the AMSR‐E thin‐ice algorithm developed for the Arctic Ocean with some modification. We provided a 16‐yr data set of ice production from the 2002/2003 to 2018/2019 seasons, excepting the 2011/2012 season. It is found that the Anadyr polynya has by far the highest sea ice production (average of 93 km3/yr) and accounts for more than 30% of all polynya ice production in the Bering Sea. The combined ice production in the Anadyr, Anadyr Strait, and St. Lawrence polynyas becomes the second‐largest ice production during the AMSR‐E period in the Northern Hemisphere. It is considered that the high ice production in the Anadyr polynya produces cold, saline, nutrient‐rich water, so‐called Anadyr Water, which would contribute to the formation of the cold halocline layer and high biological productivity. The ice production in the Anadyr polynya shows very large year‐to‐year variability. The record low ice extent year of the 2017/2018 season is also the lowest ice production year; the production is only one tenth of the highest value, observed during the 2015/2016 season. The high sensitivity of the wind direction and strength to the location of the Aleutian Low causes this large variability. We also built reconstruction schemes of ice production in the polynyas, using the offshore wind and air temperature, by multiple linear regression.
Abundances and Microphysical Properties of Light‐Absorbing Iron Oxide and Black Carbon Aerosols Over East Asia and the Arctic
Authors: Yoshida Atsushi , Moteki Nobuhiro , Ohata Sho , Mori Tatsuhiro , Koike Makoto , Kondo Yutaka , Matsui Hitoshi , Oshima Naga , Takami Akinori , Kita Kazuyuki
Published: June 2020

Black carbon (BC), brown carbon, and light‐absorbing iron oxides (FeOx) aerosols affect Earth's energy budget through their strong absorption of solar radiation. FeOx aerosols can also affect global biogeochemical cycles through their role as a nutrient for oceanic phytoplankton. However, observational data for these aerosols required for evaluating their effects using global models are scarce, especially for FeOx. Here, we summarize and compare the data sets of BC and FeOx from five ground‐based and three aircraft observation campaigns conducted in the East Asian and Arctic regions during the 2009–2018 period acquired using a modified single‐particle soot photometer. In these campaigns, >80% of FeOx‐containing aerosols in the 170–270 nm FeOx core size range had microphysical features indicating an anthropogenic origin. The particle size distribution for each of the BC and FeOx was similar in all of the data sets except for those dominated by fresh urban pollution or pristine Arctic air. The campaign‐averaged mass concentrations of FeOx and BC were ~60–360 ng/m3 and ~240–1,300 ng/m3, respectively, in East Asia, and ~6 ng/m3 and ~20–30 ng/m3, respectively, in the Arctic. The campaign‐averaged FeOx/BC mass concentration ratio varied within a narrow range of 0.2–0.6 in both East Asian and Arctic regions. In every campaign, FeOx, BC, and carbon monoxide were tightly correlated with each other with similar slope to the urban campaigns (around Tokyo), implying the spatiotemporal variation of anthropogenic FeOx emission around northern middle‐to‐high latitudes is similar to those of anthropogenic BC and CO emissions.
Hydraulic Fracturing‐Induced Seismicity
Authors: Schultz Ryan , Skoumal Robert J. , Brudzinski Michael R. , Eaton Dave , Baptie Brian , Ellsworth William
Published: June 2020

Hydraulic fracturing (HF) is a technique that is used for extracting petroleum resources from impermeable host rocks. In this process, fluid injected under high pressure causes fractures to propagate. This technique has been transformative for the hydrocarbon industry, unlocking otherwise stranded resources; however, environmental concerns make HF controversial. One concern is HF‐induced seismicity, since fluids driven under high pressure also have the potential to reactivate faults. Controversy has inevitably followed these HF‐induced earthquakes, with economic and human losses from ground shaking at one extreme and moratoriums on resource development at the other. Here, we review the state of knowledge of this category of induced seismicity. We first cover essential background information on HF along with an overview of published induced earthquake cases to date. Expanding on this, we synthesize the common themes and interpret the origin of these commonalities, which include recurrent earthquake swarms, proximity to well bore, rapid response to stimulation, and a paucity of reported cases. Next, we discuss the unanswered questions that naturally arise from these commonalities, leading to potential research themes: consistent recognition of cases, proposed triggering mechanisms, geologically susceptible conditions, identification of operational controls, effective mitigation efforts, and science‐informed regulatory management. HF‐induced seismicity provides a unique opportunity to better understand and manage earthquake rupture processes; overall, understanding HF‐induced earthquakes is important in order to avoid extreme reactions in either direction.
Anomaly Kriging Helps to Remove Bias in Spatial Model Runoff Estimates
Authors: Loonat Nadir I. , Van Dijk Albert I. J. M. , Hutchinson Michael F. , Weerts Albrecht H.
Published: June 2020

The low spatial density of streamflow gauging stations limits the accuracy of spatial streamflow estimates in many parts of the world. Strategies to improve runoff estimates in the absence of dense measurements have tended to focus on estimating parameters of runoff models in ungauged regions, through so‐called parameter regionalization methods. However, parameter regionalization can be affected by overdependence on calibration at gauged sites, model parameter equifinality, and ensuing estimation errors. As a result, spatial model runoff estimates typically exhibit spatially correlated biases. This analysis attempts to enhance the use of observations in spatial runoff estimation. Specifically, we assessed the potential to reduce systematic errors by spatially interpolating residuals (i.e., errors) between prior grid‐based streamflow estimates for Australia at 0.05° × 0.05° grid from the Australian Bureau of Meteorology's calibrated, operational Australian Water Resources Assessment Landscape model (AWRA‐L) and streamflow gauging records from 780 unimpeded, relatively small catchments. We analyzed spatial autocorrelation in residuals and tested an efficient two‐step correction approach involving a uniform correction and subsequent kriging of residuals. The approach removed an average of 41% of systematic bias in the model estimates and also improved other model performance measures. Further reduction in errors at shorter timescales may be achievable through a temporally hierarchical correction scheme.
Hackathon Participants Solve Global Problems—from Home
Authors: Wendel JoAnna
Published: June 2020

More than 200 participants from 38 countries joined the virtual INSPIRE Hackathon to solve problems in food security, transportation, and more.
New Crustal Vs Model Along an Array in South‐East China: Seismic Characters and Paleo‐Tethys Continental Amalgamation
Authors: Li Tingzi , Zhao Liang , Wan Bo , Li Zheng‐Xiang , Bodin Thomas , Wang Kun , Yuan Huaiyu
Published: June 2020

The assembly of East Asia was closely linked to the closure of the Tethyan oceans. In south‐east China, the closure of the Paleo‐Tethys ocean led to a continental collision between the South China and North China blocks (SCB and NCB), forming the world renowned (ultra‐) high pressure (UHP) metamorphic belt of the Dabie‐Sulu Orogen. The region was subsequently reworked by postorogenic extensional processes. These tectonic processes likely have left lithospheric scars identifiable by seismic imaging techniques. Here we characterize seismic structures across the orogen and analyze processes related to the closure of the Paleo‐Tethys. Using cutting‐edge tomographic approaches and ambient noise dispersion data, we developed a fine‐scale crustal shear‐wave velocity model beneath key crustal domains in the region. Distinct crustal scale velocity domains are identified, corresponding to the normal Precambrian crust, slow‐velocity suture zones and fault systems, and fast‐velocity orogens, suggesting a deep root of the corresponding surface geological features. By combining recent models of active‐source, gravity and magnetotellurics, characteristic lithospheric deformation patterns such as crustal thrust systems and lithospheric wedges can be inferred, which are attributed to a northward subduction of the SCB lithosphere and the eventual continental collision after the closure of the Paleo‐Tethys Ocean.
Impact of Cloud Longwave Scattering on Radiative Fluxes Associated With the Madden‐Julian Oscillation in the Indian Ocean and Maritime Continent
Authors: Ren Tong , Yang Ping , Schumacher Courtney , Huang Xianglei , Lin Wuyin
Published: June 2020

Previous studies suggested that cloud longwave radiation contributes to the development and maintenance of the Madden‐Julian Oscillation (MJO) and model‐based convection is highly sensitive to the radiation scheme. However, currently used radiation schemes do not take cloud longwave scattering into account, resulting in an overestimation of the outgoing longwave radiation (OLR) and an underestimation of the downward longwave flux at the surface. We use combined active and passive satellite cloud property retrievals to quantify the one‐layer cloud OLR and heating rate (HR) biases introduced by neglecting cloud longwave scattering in the Indian Ocean and Maritime Continent in the context of MJO, with a focus on its phases 3, 5, and 6. The results show that the satellite‐detected one‐layer cloud area consists primarily of ice clouds, particularly during the boreal winter in the 4‐year study period. An increased ice cloud area fraction of one‐layer cloud groups is present up to 5 days before the onset of MJO events. If longwave scattering is neglected, the composite mean OLR overestimation over the one‐layer ice cloud area from 5 days before to 4 days after the MJO passage is approximately 3.5 to 5.0 W m−2. Neglecting longwave scattering also leads to a HR underestimation at cloud base and an overestimation at cloud top, making the base‐to‐top heating gradient less sharp at the cloud‐resolving scale.
An Analytical Solution of Groundwater Flow in a Confined Aquifer With a Single‐Well Circulation System
Authors: Tu Kun , Wu Qiang , Simunek Jirka , Chen Chaofan , Zhu Ke , Zeng Yifan , Xu Shengheng , Wang Yang
Published: June 2020

In this study, a general analytical model for the single‐well circulation system is developed to analyze transient drawdown in a confined aquifer. The analytical solution of transient drawdown in the Laplace domain, which is numerically inverted into the time domain using the Stehfest method, is derived by employing a combination of the Laplace and Fourier cosine transforms. The characteristics of transient drawdown and the effects of different parameters related to the single‐well circulation system on drawdown are investigated. Furthermore, the analytical solution under steady‐state conditions is obtained using the Fourier cosine transform. The results show that steady drawdown contours are symmetric around a horizontal midplane of an aquifer and vary tremendously with distance from the well axis. The contours of drawdown around the sealed section are dense, meaning that the hydraulic gradient in this area is relatively large. The sensitivity analysis, performed to evaluate the characteristics of drawdown to changes in each parameter, indicates that the radial hydraulic conductivity and the length of the sealed section have a large impact on the drawdown and that each parameter has its influence period on the drawdown.