Combined Scanning Research Articles

Value of the color Doppler imaging mode in improving physicians' diagnostic performance in patients with mid-ureteric stones larger than 5mm: a retrospective study.

The aim of this study was to retrospectively evaluate the value of the color Doppler flow imaging mode compared to the gray-scale mode for diagnosing mid-ureteric stones larger than 5mm. We consecutively collected images from 79 patients possibly suffering from mid-ureteric stones under gray-scale and color Doppler flow imaging modes. Using computed tomography as the gold standard, all the included images were reviewed in a blinded manner for the confirmation of ureteral stones by 15 physicians divided into three groups according to their clinical experience level (resident, attending, and senior). During the evaluation process, the evaluation consistency was calculated and compared using Kendall's coefficient of concordance (Kendall's W). Moreover, diagnostic performance considering gray-scale and color imaging modes was compared. Especially for the diagnosis of mid-ureteric stones larger than 5mm, the Kendall's W for the combined gray-scale and color Doppler flow imaging ultrasound scanning modes was greater than that for the gray-scale mode (P < 0.05). Additionally, significant improvements in the diagnostic sensitivity, negative predictive value, and accuracy were noted with color Doppler imaging (P < 0.05). Under isolated gray-scale mode, the resident group had reduced diagnostic sensitivity and negative predictive value and poorer accuracy compared with the attending and senior groups (P < 0.05). In contrast, no significant differences in the combined gray-scale and color Doppler flow imaging modes were noted among all groups (P > 0.05). In summary, the color Doppler flow imaging mode is useful for the diagnosis of mid-ureteric stones larger than 5mm, especially in the resident group.

Joint metallothermic reduction of titanium and rare refractory metals of V group

The features of phase formation during the joint aluminothermic reduction of titanium, niobium, tantalum, vanadium from their oxides using methods of thermodynamic modeling, differential thermal and X-ray phase analysis were studied. Computer thermodynamic modeling made it possible to predict the optimal temperature conditions in the metallothermic process, composition and ratio of reagents in the charge, behavior of elements and sequence of phase formation. Thermodynamic calculations were supplemented by differential thermal studies using the combined scanning calorimetry method to identify the kinetic and thermochemical components of the process. An analysis of theoretical and experimental data allowed us to establish that the interaction of aluminum with titanium dioxide proceeds through the stage of titanium monoxide formation and features by the formation of TixAly intermetallic compounds of various compositions (TiAl3, TiAl, Ti2Al) depending on the Al and TiO2 ratio in the charge. When titanium dioxide is partially replaced by niobium, tantalum and vanadium oxides, the metallothermic process during interactions in the Al–TiO2–Nb2O5, Al–TiO2–Ta2O5 and Al–TiO2–V2O5 systems has a similar nature, enters the active phase once liquid aluminum appears, is accompanied by exothermic effects and features by the priority formation of titanium aluminides and binary and ternary intermetallic aluminum compounds with Group 5 rare refractory metals – AlNb3, Al3Nb, Al3Ta, Al3(Ti1–х, Taх), Al3(Ti0,8V0,2). The joint conversion of titanium dioxide and rare refractory metal pentoxides during the reduction process is carried out through sequential and parallel stages of the formation of simple and complex element oxides with low oxidation states.

Additive manufacturing of tungsten using directed energy deposition for potential nuclear fusion application

Building better nuclear fusion equipment with reduced cost is important for a sustainable society. In this study, pure tungsten is deposited on different steel substrates by directed energy deposition (DED). Specifically, the deposited layers with graded tungsten content by low and high laser scanning speed are fabricated. In addition, the processing parameters were optimized by analyzing the microstructure, phases and defects. Results show that the 9-layer sample (3000 W @ 3000 mm/min) exhibits a better thermal performance, which the thermal conductivity is about 73.75 W/(m·K) at room temperature and 147.45 W/(m·K) at 900 °C, respectively. Finally, the surface of the manufactured thick deposited layer by high-low combined laser scanning speed can reach a high tungsten content of up to 99.78 wt%. It is believed that the additive manufacturing of pure tungsten by DED can combine the advantages of tungsten and steel substrates, and simplify the manufacturing process of thermo-nuclear fusion devices.

Characterization of discontinuity surface morphology based on 3D fractal dimension by integrating laser scanning with ArcGIS

The fractal geometry method has been employed to quantitatively characterize the roughness of a rock discontinuity, which is one of the key factors affecting its shear strength and the seepage characteristics of a rock mass. However, the current fractal methods involving the three-dimensional discontinuity morphology suffer from one or more problems, such as a complicated calculation procedure, an inaccurate calculation result and an inability to characterize the undulation and anisotropy of a discontinuity. To cope with these problems, the discontinuities in artificial granite samples with irregular and undulating surfaces were taken as examples, and a quantitative study on the discontinuity morphology was conducted based on the method of three-dimensional laser scanning in combination with ArcGIS data processing, geographical research, theoretical calculations and regression analysis. After performing systematic research, we proposed an extensive 3D fractal dimension including three discontinuity morphological parameters, i.e. the fractal dimension of discontinuity morphology, the ratio between the maximal undulating amplitude and the discontinuity length, and the average value of all the apparent dip angles of the discontinuity surfaces dipping opposite the shear direction. The extensive 3D fractal dimension can comprehensively characterize the roughness, undulation and anisotropy of the discontinuity morphology. A set of theoretical calculation methods were then developed to determine the three discontinuity morphological parameters of the extensive 3D fractal dimension based on ArcGIS. We finally established a mathematical expression of the extensive 3D fractal dimension. Compared with the current fractal methods, the extensive 3D fractal dimension can effectively compensate for the inability to characterize the undulation and anisotropy of the discontinuity morphology. Its calculation methods have the advantages of simplification, low-time consumption and high precision.

GAS SIPS AND SHALLOW ACCUMULATIONS OF GAS ON THE SHELF OF TURKEY IN THE BLACK SEA

It has been suggested that shelf and slope sediments of high deposition rate are methane sources, whereas the deep basin is methane sink. The methane production and migration in sediments may cause massive slope failures so methane is geologically important. Methane production is also economically important as methane seeps may indicate the presence at depth of hydrocarbon reservoirs, and methane hydrate may be an important source of energy. Recent studies in marine geology indicate potential geo-resources in the Turkish coast of Black Sea. The Black Sea sediments are rich in calcite and organic carbon, the latter showing a high degree of preservation due to anoxia in the waters below 100-150 m. Different marine geophysical surveys at different times were carried out in order to understand the sedimentary features of gas-saturated sediments in the Black Sea. Multibeam, side scan sonar, sub-bottom profiler and multi-channel seismic data were collected to make both high-resolution bathymetric and reflectivity maps of the seafloor. In some cruises, deep-tow combined side scan sonar and subbottom profiler was used to obtain acoustic images of both the seafloor surface and subbottom sediments. Several different structures were observed in the Black Sea basin as slumps, pockmarks, faults, gas chimneys, shallow gas accumulations and dome-like structures. Structures, which contain gas hydrates, are present on the seismic sections as strong acoustic reflections.

Table-top combined scanning X-ray small angle scattering and transmission microscopies of lipid vesicles dispersed in free-standing gel.

A mm thick free-standing gel containing lipid vesicles made of 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC) was studied by scanning Small Angle X-ray Scattering (SAXS) and X-ray Transmission (XT) microscopies. Raster scanning relatively large volumes, besides reducing the risk of radiation damage, allows signal integration, improving the signal-to-noise ratio (SNR), as well as high statistical significance of the dataset. The persistence of lipid vesicles in gel was demonstrated, while mapping their spatial distribution and concentration gradients. Information about lipid aggregation and packing, as well as about gel density gradients, was obtained. A posteriori confirmation of lipid presence in well-defined sample areas was obtained by studying the dried sample, featuring clear Bragg peaks from stacked bilayers. The comparison between wet and dry samples allowed it to be proved that lipids do not significantly migrate within the gel even upon drying, whereas bilayer curvature is lost by removing water, resulting in lipids packed in ordered lamellae. Suitable algorithms were successfully employed for enhancing transmission microscopy sensitivity to low absorbing objects, and allowing full SAXS intensity normalization as a general approach. In particular, data reduction includes normalization of the SAXS intensity against the local sample thickness derived from absorption contrast maps. The proposed study was demonstrated by a room-sized instrumentation, although equipped with a high brilliance X-ray micro-source, and is expected to be applicable to a wide variety of organic, inorganic, and multicomponent systems, including biomaterials. The employed routines for data reduction and microscopy, including Gaussian filter for contrast enhancement of low absorbing objects and a region growing segmentation algorithm to exclude no-sample regions, have been implemented and made freely available through the updated in-house developed software SUNBIM.

Advances in multimodal imaging in ophthalmology.

Multimodality ophthalmic imaging systems aim to enhance the contrast, resolution, and functionality of existing technologies to improve disease diagnostics and therapeutic guidance. These systems include advanced acquisition and post-processing methods using optical coherence tomography (OCT), combined scanning laser ophthalmoscopy and OCT systems, adaptive optics, surgical guidance, and photoacoustic technologies. Here, we provide an overview of these ophthalmic imaging systems and their clinical and basic science applications.

Host guest chemistry and supramolecular doping in triphenylamine-based covalent frameworks on Au(111).

The post-synthetic modification of covalent organic frameworks (COFs) via host-guest chemistry is an important method to tailor their electronic properties for applications. Due to the limited structural control in the assembly of two-dimensional surface-supported COFs, supramolecular networks are traditionally used at present for host-guest experiments on surfaces, which lack structural and thermal stability, however. Here, we present a combined scanning tunneling microscopy and density functional theory study to understand the host-guest interaction in triphenylamine-based covalently-linked macrocycles and networks on Au(111). These triphenylamine-based structures feature carbonyl and hydrogen functionalized pores that create preferred adsorption sites for trimesic acid (TMA) and halogen atoms. The binding of the TMA through optimized hydrogen-bond interactions is corroborated by selective adsorption positions within the pores. Band structure calculations reveal that the strong intermolecular charge transfer through the TMA bonding reduces the band gap in the triphenylamine COFs, demonstrating the concept of supramolecular doping by host-guest interactions in surface-supported COFs. Halogen atoms selectively adsorb between two carbonyl groups at Au hollow sites. The mainly dispersive interaction of the halogens with the triphenylamine COF leads to a small downshift of the bands. Most of the halogens change their adsorption position selectively upon annealing near the desorption temperature. In conclusion, we demonstrate evidence for supramolecular doping via post-synthetic modification and to track chemical reactions in confined space.

On Vacancy and Solute Co-Segregated η1 Interface in Over-Aged Al-Zn-Mg Alloys

We represent a combined first-principles and scanning transmission electron microscopy (STEM) study of the η1A1 interfaces in an over-aged Al-Zn-Mg alloy. As one of the major η-MgZn2 precipitate phase variants, η1A1 tends to form highly coherent interfaces with Al matrix, along with various unique solute segregation patterns on its interfacial layers. The interface phase diagram suggests either an Mg-rich or a Zn-rich interface, depending on the chemical potential range of Zn. Further segregation calculations, however, strongly suggest the STEM Z-contrast imaged interface to be a vacancy and solute co-stabilized Mg-rich structure that is favored at relatively low Zn chemical potentials. Based on our experimental and calculation results, the profound thermodynamics origin of the η1A1 interface and its intricate segregation behavior were clarified and described using a generalized structure model. The η1A1l interface structure and segregation at higher Zn chemical potentials were also predicted for future experimental validation.

Additive value of positron emission tomography/computed tomography scan for detection of aortic tube graft infection: a case report.

BackgroundDiagnosis of aortic graft infection is challenging, and delayed diagnosis is associated with poor prognosis. Positron emission tomography/computed tomography (PET/CT) has improved diagnostic accuracy.Case summaryA patient with a history of congenital heart disease was admitted due to fever. He had a history of four cardiac surgeries, including the Bentall procedure for endocarditis. Blood cultures were negative. A semi-mobile mass was detected in the distal portion of the aortic tube graft in echocardiography. PET/CT scan was used to confirm tube graft infection and to support proceeding to cardiac surgery.DiscussionUsing multimodality imaging, including PET/CT scan in combination with echocardiography, can improve diagnostic accuracy for the detection of aortic tube graft infection, infection of prosthetic valves, or intra-cardiac devices, especially in high-risk surgical cases.

Evaluation of the FUSION-X-US-II prototype to combine automated breast ultrasound and tomosynthesis

ObjectiveThe FUSION-X-US-II prototype was developed to combine 3D automated breast ultrasound (ABUS) and digital breast tomosynthesis in a single device. We evaluated the performance of ABUS and tomosynthesis in a single examination in a clinical setting.MethodsIn this prospective feasibility study, digital breast tomosynthesis and ABUS were performed using the FUSION-X-US-II prototype without any change of the breast position in patients referred for clarification of breast lesions with an indication for tomosynthesis. The tomosynthesis and ABUS images of the prototype were interpreted independently from the clinical standard by a breast diagnostics specialist. Any detected lesion was classified using BI-RADS® scores, and results of the standard clinical routine workup (gold standard) were compared to the result of the separate evaluation of the prototype images. Image quality was rated subjectively and coverage of the breast was measured.ResultsOne hundred one patients received both ABUS and tomosynthesis using the prototype. The duration of the additional ABUS acquisition was 40 to 60 s. Breast coverage by ABUS was approximately 80.0%. ABUS image quality was rated as diagnostically useful in 86 of 101 cases (85.1%). Thirty-three of 34 malignant breast lesions (97.1%) were identified using the prototype.ConclusionThe FUSION-X-US-II prototype allows a fast ABUS scan in combination with digital breast tomosynthesis in a single device integrated in the clinical workflow. Malignant breast lesions can be localized accurately with direct correlation of ABUS and tomosynthesis images. The FUSION system shows the potential to improve breast cancer screening in the future after further technical improvements.Key Points• The FUSION-X-US-II prototype allows the combination of automated breast ultrasound and digital breast tomosynthesis in a single device without decompression of the breast.• Image quality and coverage of ABUS are sufficient to accurately detect malignant breast lesions.• If tomosynthesis and ABUS should become part of breast cancer screening, the combination of both techniques in one device could offer practical and logistic advantages. To evaluate a potential benefit of a combination of ABUS and tomosynthesis in screening-like settings, further studies are needed.

CONTROLLING OPTICAL BEAMS USING MUTUALLY COMPLEMENTARY SCANNERS

Devices based on scanners (deflectors, scanning devices) with mutually complementary characteristics can be a solution to control problems of an optical scanning beam in a number of applications. The paper considers optical-mechanical, electronic, acousto-optical, electro-optical, as well as microelectromechanical (MEMS), micro-optical electromechanical (MOEMS) scanners as components of combined scanning devices. The qualitative indicators of composite scanning, including the speed, resolution, control accuracy of the optical beam, the dimensions of the scanned space, etc., are given. Along with the advantages, the difficulties arising in the implementation of combined scanning are noted.

High temperature oxidation behaviour of non-equimolar AlCoCrFeNi high entropy alloys

Oxidation properties of AlCoCrFeNi high entropy alloys, i.e. 5%Al–35%Co–25%Cr–15%Fe–20%Ni (Al5Co35Cr25Fe15Ni20) and 5%Al–25%Co–20%Cr–15%Fe–35%Ni (Al5Co25Cr20Fe15Ni35), were investigated in air atmosphere at 1273 K. Thermogravimetry (TG) investigations determined that, under these conditions, the samples demonstrate scale growth according to the parabolic rate law with rate constants the order of 10−11 g2cm−4s−1. Combined scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS) surface analysis and X-ray diffraction (XRD) studies revealed that the formed protective scales consisted primarily of chromium oxide. Underneath the external Cr2O3 scale, a thin layer of the metallic substrate can be found. Below that, an internal chromium oxide scale with discontinuous Al2O3 can be observed. Al-rich precipitates can also be found in the internal layers, as well as the metallic substrates after oxidation. XRD analysis also indicated that the initial materials are single FCC phase solid solutions. From all these studies it can be concluded that both Co and Ni-rich non-equimolar AlCoCrFeNi high entropy alloys exhibit similar high temperature oxidation behaviour. Furthermore, each of the alloys has promising anti-corrosion properties that can possibly be further improved on, e.g. with higher aluminium content inside the materials.

Designer spin order in diradical nanographenes

The magnetic properties of carbon materials are at present the focus of intense research effort in physics, chemistry and materials science due to their potential applications in spintronics and quantum computing. Although the presence of spins in open-shell nanographenes has recently been confirmed, the ability to control magnetic coupling sign has remained elusive but highly desirable. Here, we demonstrate an effective approach of engineering magnetic ground states in atomically precise open-shell bipartite/nonbipartite nanographenes using combined scanning probe techniques and mean-field Hubbard model calculations. The magnetic coupling sign between two spins was controlled via breaking bipartite lattice symmetry of nanographenes. In addition, the exchange-interaction strength between two spins has been widely tuned by finely tailoring their spin density overlap, realizing a large exchange-interaction strength of 42 meV. Our demonstrated method provides ample opportunities for designer above-room-temperature magnetic phases and functionalities in graphene nanomaterials.

Radiation Mapping and Laser Profiling Using a Robotic Manipulator

The use of a robotic arm manipulator as a platform for coincident radiation mapping and laser profiling of radioactive sources on a flat surface is investigated in this work. A combined scanning head, integrating a micro-gamma spectrometer and Time of Flight (ToF) sensor were moved in a raster scan pattern across the surface, autonomously undertaken by the robot arm over a 600 × 260 mm survey area. A series of radioactive sources of different emission intensities were scanned in different configurations to test the accuracy and sensitivity of the system. We demonstrate that in each test configuration the system was able to generate a centimeter accurate 3D model complete with an overlaid radiation map detailing the emitted radiation intensity and the corrected surface dose rate.

Lithium Deposition in Single-Ion Conducting Polymer Electrolytes

Lithium metal is considered as potential anode material due to its superior energy density compared to conventional graphitic anodes.[1] However, so far its application is restricted due to inhomogeneous Li deposition during cycling, potentially causing contact losses between bulk and deposited Li or short circuit of the cell related to formation of ‘dendritic’ deposits. Theoretical models propose that single-ion conducting electrolytes afford safe and ‘dendrite-free’ cycling of lithium metal batteries (LMBs) due to immobilization of anions and thus, prevention of cell polarization.[2] In this contribution, a blend type quasi-solid single-ion conducting polymer electrolyte (SIPE), a polymer class that has attracted much attention recently, is consulted for analysis of the Li deposition behaviour. Combined scanning electron microscopy (SEM) and X-ray tomography are applied illustrating the occurrence of inhomogeneous, rather dense Li deposits agglomerating and eventually penetrating the polymer membrane independent of the applied current densities. Raman mapping, nano-mechanical (QNM) and electrochemical strain microscopy (ESM) mapping further reveal that membrane constituents and consequently membrane properties such as (mechanical) stiffness and ionic conductivity are non-homogeneously distributed within the membrane related to the phased separated morphology of the blend. This implies that the intrinsic nature of the polymer membrane is responsible for the formation of conduction channels, also governing the homogeneity of Li deposition. Beyond that, it is demonstrated how characteristics of the Li│polymer interface in salt- free SIPEs limit the achievable cell performance, particularly since limited Li+ ion diffusivity through the interfaces substantially impair efficient charge carrier transport within the cell system.

Surface Conductivity of the Honeycomb Spin–Orbit Mott Insulator Na2IrO3

The search for materials with novel and unusual electronic properties is at the heart of condensed matter physics as well as the basis to develop conceptual new technologies. In this context, the correlated honeycomb transition metal oxides have attracted large attention for both, being a possible experimental realization of the theoretically predicted magnetic Kitaev exchange and the theoretical prospect of topological nontriviality. Mott‐insulating Na2IrO3 is prototypical among these materials, characterized by crystal field splitting, spin–orbit coupling, and Hubbard repulsion being on similar energy scales. Herein, a combined electrical transport and scanning tunneling spectroscopy (STS) study of the surface of sodium iridate cleaved and in situ investigated under ultrahigh vacuum is reported. Temperature‐dependent transport measurements prove the existence of surface conductance with a surprisingly high and temperature‐independent conductivity. STS shows a variety of different spectra. Most importantly, a significant density of states is found within the bandgap of sodium iridate at the surface. Based on the local spectroscopic information, multiple conductive channels with differing nature being simultaneously apparent in this material are discussed.

Evaluation of the Cesarean Scar Niche In Women With Secondary Infertility Undergoing ICSI Using 2D Sonohysterography Versus 3D Sonohysterography and Setting a Standard Criteria; Alalfy Simple Rules for Scar Assessment by Ultrasound To Prevent Health Problems for Women.

BackgroundMany expressions were used to define the defect that is seen by ultrasound after cesarean section (CS) namely scar defect, niche, isthmocele, uterine pouch or diverticula.ObjectiveTo compare the accuracy of 2 dimensional sonohysterography (2D SHG) to 3 dimensional sonohysterography (3D SHG) in evaluating cesarean section uterine scar depth (D), base width (BW), width (W) and residual myometrial thickness (RMT) in women with secondary infertility and establishment of a standard criteria; Alalfy simple rules for scar assessment.Patients and MethodsThis was an observational cross-sectional comparative study that was conducted on women who presented with secondary infertility and were candidates for intracytoplasmic sperm injection (ICSI) and giving a history of a previous cesarean section. Assessment of uterine scar in each woman was performed using 2D transvaginal ultrasound with sonohysterography (SHG) followed by 3D transvaginal with SHG with evaluation of niche depth, width, RMT, niche BW and RMT/depth ratio. The study was conducted at Algezeera hospital, Egypt.ResultsThe present study revealed that 3D ultrasound with SHG is superior in evaluation of the RMT and niche width prior to ICSI providing better characterization of the scar niche.ConclusionScar niche should be assessed by a combined integrated 2D SHG and 3D SHG scan with the specific geometrical and anatomical considerations, Alalfy simple rules for scar niche assessment that involvemeasurement of niche depth, (Base width) BW, width, RMT and RMT/depth ratio in sagittal plane, RMT in coronal plane / niche width in coronal plane ratio (ratio less than 1 denotes scar weakness with more liability for dehiscence).Trial RegistrationClinical Trials.gov Id NCT04076904.

Features of Two-Dimensional Bifurcations during Dissipative Electron Tunneling in Arrays of Au Nanoparticles

Within the 2D theory of dissipative tunneling in the semiclassical approximation (a rarefied gas of instanton–anti-instanton pairs) at a finite temperature in the presence of an external electric field, the features of tunneling transport in the planar structures with the quantum dots made of colloidal gold—which, presumably, possess the properties of a metamaterial—are investigated. It is shown experimentally that either a single effect or a double effect of 2D tunnel bifurcations (in the form of a kink or kinks on the tunneling current–voltage curve) is observed depending on the position of the cantilever tip of a combined atomic force and scanning tunneling microscope (AFM/STM), which can be either above a single quantum dot or between two adjacent quantum dots, respectively. As our theoretical model shows, such a regime of double bifurcation (a double smoothed kink on the tunneling current–voltage curve) that is associated with the manifestation of the properties of a metamaterial by the structure under study. A convincing qualitative agreement is obtained between the experimental current–voltage characteristics and the field dependence of the probability of 2D dissipative tunneling in the two investigated regimes with due regard for the observed quantum beats (oscillations) in the vicinity of 2D bifurcation points.

Gastric Fistula in the Chest After Sleeve Gastrectomy: a Systematic Review of Diagnostic and Treatment Options.

This study aimed to establish the optimal diagnostic and treatment algorithm for the management of gastric fistula in the chest (GFIC) after sleeve gastrectomy (SG) through a systematic review of published cases. A multi-database search was performed, which produced 1182 results, of which 26 studies were included in this systematic review. The initial presentation included subphrenic collections, leaks, or (recurrent) pneumonia with associated symptoms such as persistent cough, fever, and/or dyspnea. Computed tomography (CT) scan in combination with either upper gastrointestinal (UGI) series or an esophagogastroduodenoscopy (EGD) was used to adequately diagnose the fistulas. Initial treatment was either with clips and/or clips and stents that were placed endoscopically. When unsuccessful in the majority of the cases, the surgical treatment consisted of total gastrectomy and Roux-en-Y esophagojejunostomy in a laparoscopic or open fashion.