bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive direct metal/material deposition process using a fuzzy logic-based controller
Authors: Hua Y. , Choi J.
Published: June 2006

The laser aided direct metal/material deposition (DMD) process is a layered manufacturing process able to produce a three-dimensional (3D) part directly from a computer aided design image. A closed-loop feedback control system is considered as a requirement to ensure dimensional accuracy. For conventional control methods, the effectiveness of process control strongly relies on accuracy of the analytical model of the system behavior. However, development of such an analytical model is quite difficult and impractical, since coupled process variables cause the complexity and nonlinearity of the DMD process. Fuzzy logic-based control, which no model but only knowledge of the process is required for decision making using this control technique, is attempted to overcome the difficulty. A proportional integral differential such as a fuzzy logic-based controller was developed for adaptive deposition during the DMD process. The controller has the capability of continuously tracking the reference height by varying the laser power adaptively, thus depositing a clad line with varying deposition height and a layer with a curved surface. This feature provides a potential of building 3D parts with nonlinear geometry such as overhang, while maintaining the accuracy of surface curvature. Simulation was performed tuning up fuzzy controller parameters with an experiment-based fuzzy logic model of the DMD process and simulated results were compared with experimental results to verify the performance of the controller.
Optical viewport assembly for eye-safe monitoring of thin film deposition
Authors: Robbie Kevin , Buzea Cristina , Landry Olivier , Dean Cory
Published: June 2006

This article discusses the design and application of a simple eye-safe monitoring assembly of thin film deposition and its advantages over the existent eye protection filters. This assembly prevents users from being exposed to the radiation field caused by lasers or incandescent objects during thin film deposition. Its design is simple, the device being reliable and easy to operate.
Three-dimensional analytical model on laser-powder interaction during laser cladding
Authors: Huang Yan-Lu , Liu Jian , Ma Nai-Heng , Li Jian-Guo
Published: June 2006

To compute the attenuation of laser power by powder stream and the temperature distribution of the powder particles arriving at different sites on the surface of the workpiece, a three-dimensional analytical model was presented based on Lambert-Beer theorem, Mie’s theory, and heat equilibrium principle. The obtained results revealed that for a given stream spread and speed of powder particles, the laser intensity distribution of laser spot and the temperature distribution of the powder particles reaching the surface of workpiece are both greatly affected by the powder feeding rate and the feeding angle. It was suggested that the presented results should be considered in the laser cladding process in order to control the dynamic processes in laser molten pool.
Magnetic stirring during laser welding of aluminum
Authors: Vollertsen Frank , Thomy Claus
Published: June 2006

The use of magnetic fields to influence melt flow is a well-established method, e.g., in foundry technology. For arc welding processes (especially tungsten inert gas welding), a process called magnetic stirring was first proposed, patented, and investigated in the 1970s. The central aim was to improve (by the help of an alternating magnetic field coaxial with the arc axis) weld quality especially in aluminum by the combined effects of arc current and magnetic field. It was established that such fields are indeed capable of influencing weld bead appearance, of increasing the degree of dilution, of decreasing pore formation and of producing a finer grain structure. However, the process never gained wide industrial acceptance. In the late 1990s, some efforts have been taken to apply constant magnetic fields to laser welding processes, aiming at influencing weld geometry, reducing porosity, and potentially increasing welding speed. However, neither have any detailed statements been made on possibilities to influence melt flow and, consequently, filler metal distribution, nor on the application of alternating magnetic fields on laser welding. To help this situation, basic studies on magnetically influencing melt flow during laser welding of aluminum have been conducted. To that end, alternating fields have been coaxially applied with magnetic flux densities up to 60 mT and frequencies in the range of 0–20 Hz. It was demonstrated by the help of a specially developed method that, depending on the parameters chosen, such fields are indeed capable of influencing melt flow and weld pool dilution, thus “stirring” the weld metal. The results have been so promising that further investigations will be conducted, also focusing on laser hybrid welding especially of hot-cracking sensitive aluminum alloys.
Effect of process parameter on turbulent transport in a laser surface alloying process
Authors: Chatterjee Dipankar , Chakraborty Nilanjan , Chakraborty Suman
Published: June 2006

A three-dimensional, transient numerical model is used for analyzing turbulent momentum, heat, and mass transport in typical laser surface alloying processes. The Reynolds averaged conservation equations are solved using a finite volume approach. The turbulent transport is accounted for by a suitably modified high Reynolds number k-ε model in the presence of a continuously evolving phase-change interface. Phase change aspects of the problem are addressed using a modified enthalpy-porosity technique. Subsequently, the developed turbulent transport model is used to simulate single pass laser surface alloying processes with different sets of processing parameters, such as laser power, scanning speed, and powder feedrate, in order to assess their influences on molten pool geometry and dynamics, cooling rates, as well as on species concentration distribution inside the substrate. In order to investigate the effects of turbulence, the parametric studies for the present turbulent simulation are compared with corresponding laminar simulation results. Significant differences are observed on comparing the laminar and turbulent simulation results, which provide valuable insights for controlling the process parameters based on the manufacturing needs.
Laser igniting synthesis of TiC powders with Al, Ti and C powders
Authors: Li Y. X. , Hu J. D. , Liu S. Y. , Wang H. Y. , Yang Y. , Guo Z. X.
Published: June 2006

Laser ignited self-propagating high-temperature synthesis (LISHS) was used to fabricate TiC powders. The raw powders are Ti, Al, and C powders, respectively. A pulsed Nd-yttrium–aluminum–garnet laser was used to ignite reaction in argon atmosphere. The effects of Al content and laser average energy on density, phase composition, microstructure of the reaction products, and particle size and substoichiometry of the synthesized TiC were studied. The results indicated that TiC powders with particle size ranging from 1.0 to 4.0 μm could be made by this method. TiC particulates gradually transformed from the multiangular shape to the spherical shape as laser average energy increased. Nonequilibrium TiCx was formed by LISHS reaction. The substoichiometry of the synthesized TiCx (x=0.62,0.70) was related to Al content. The density of the sintered products was smaller than that of green densities, but sintered densities increased with the increase of Al content.
The effect of shielding gas composition on welding performance and weld properties in hybrid CO2 laser–gas metal arc welding of carbon manganese steel
Authors: Fellman Anna , Kujanpää Veli
Published: June 2006

Metals industries producing large structures currently have a particular interest in hybrid laser welding processes, which possess advantages compared with conventional methods of welding. One major benefit is a reduction in deformation that enables the amount of postweld finishing work to be reduced. Assembly then also becomes simpler because of the greater accuracy that may be achieved. Larger joint tolerances may be accommodated compared with laser welding alone. By using appropriate filler metal, the weld metal composition may be controlled to meet metallurgical criteria. The hybrid CO2 laser–gas metal arc (GMA) welding process was investigated in this study; the aim being to clarify the effects of process gas composition on welding performance, weld cross section, quality, and mechanical properties, when welding carbon manganese steel. Helium, argon, and carbon dioxide were used in varying proportions as shielding gases for welding I-butt and T-butt joints. The composition of the shielding gas was found to affect welding performance, weld quality, and weld cross-section geometry. The best results were obtained by using argon, with a helium content of 40%–50% and a carbon dioxide content of 2%–5%; the exact composition depending on the groove edge quality. Hybrid laser welds of high quality may be produced in carbon manganese steel with a variety of shielding gas compositions, but to maximize productivity, reliability, and quality, while minimizing gas cost, the composition must be selected carefully.
Modeling of the melted bath movement induced by the vapor flow in deep penetration laser welding
Authors: Amara E. H. , Fabbro R. , Hamadi F.
Published: June 2006

In this article we are interested in a moving mechanism occurring in the melted bath that is produced during the deep penetration laser welding process. It concerns the displacement of the melted metal induced by the friction effect due to the interaction with the metallic vapor when it flows toward the keyhole exit. Boundary conditions resulting from a ray-tracing procedure are used in the numerical solving of the unsteady Navier–Stokes conservation equation for both liquid and gaseous phases. The melted metal is considered for the liquid phase, whereas the metallic vapor and the environing air are taken as gaseous phases. The volume of fluid approach used in our modeling allows the tracking of the vapor–liquid wall interface evolution. We will present sequences of the melted bath profiles evolution as the vapor flows and interacts with it. An estimation of the velocity of the displaced liquid boundary layer allows a comparison with experimental results concerning the expelled melted metal velocity.
Effect of oxygen in ambient atmosphere on penetration characteristics in single yttrium–aluminum–garnet laser and hybrid welding
Authors: Naito Yasuaki , Mizutani Masami , Katayama Seiji
Published: June 2006

Welding with a yttrium–aluminum–garnet (YAG) laser only or with hybrid source combined with a YAG laser and a TIG arc was carried out on Type 304 stainless steel plate with low S content in the air or in the chamber with Ar gas including 0%–15% oxygen gas. It was confirmed in both laser and hybrid welding that the penetration and geometry of welds depended upon the volume of the oxygen in the ambient atmosphere, and that a pronounced “nail head” disappeared in a weld metal containing a higher content of oxygen. An x-ray transmission real-time imaging apparatus revealed that melt flows depended on the volume ratio of oxygen in the atmosphere and there was a strong melt flow from the keyhole inlet to the surrounding pool near the top surface in pure Ar atmosphere. It is therefore considered that the melt flows induced by surface tension produces the “nail head” in pure Ar shielding atmosphere and the resulting weld becomes a wine glass shape. During YAG laser and hybrid welding in the air or in the Ar gas with the oxygen gas increased, the downward melt flows along the keyhole wall was more dominant to produce slightly deeper welds with narrower surface bead widths due to the effect of the surface tension with the positive gradient. On the other hand, the formation of shallower YAG-TIG weld beads produced in air was attributed to the mechanism that the Marangoni convection and electromagnetic convection induced by TIG arc constriction in the central part of the molten pool prevented downward melt flows from a keyhole tip resulting in deeper penetration than the tip. It was moreover confirmed that the porosity reduction in hybrid welding at a high current was due to the reduced formation of bubbles.
An experimental and theoretical investigation of combined gas- and water-atomized powder deposition with a diode laser
Authors: Pinkerton Andrew J. , Ul Haq Syed Waheed , Li Lin
Published: June 2006

Functionally graded or composite components (FGCs) have been recognized as having immense potential for many industries. So far, deposition of compositionally graded alloys is the only method that has been shown to be a practical way to produce FGCs. In this work, a second way, that allows graded structures of a single material to be formed by direct metal deposition, is investigated. Simple component samples are built using a diode laser direct metal deposition system with a side feed nozzle and blends of water- and gas-atomized 316L steel powder in varying proportions. Trends in surface finish, wall integrity, and overall wall dimensions are immediately apparent. Further analyses using optical microscopy, x-ray diffraction, and mechanical testing methods show that it is possible to produce differences in physical properties such as tensile strength and hardness across a formed component. The system is modeled and the results discussed in terms of the thermal cycle of the build material.
Investigation of the effects of nonconventional beam geometries in laser surface treatment of ceramics: Theoretical analysis
Authors: Triantafyllidis D. , Li L. , Stott F. H.
Published: June 2006

Laser surface treatment of ceramics by melting and resolidification generally leads to the formation of fully densified and homogeneous surfaces, with enhanced mechanical and physical properties. A common problem associated with the process is the formation of thermally induced cracks on solidification and cooling. This, however, can be eliminated by controlling the cooling rates and thermal gradients during processing. Such control can be achieved by applying pre- and postheating methods or by scanning the laser beam at relatively slow speeds to modify the thermal shock conditions to which the surface is subjected. The latter technique has been successfully applied to the development of crack-free surfaces in Al2O3-based refractory ceramics. The relatively slow speed, however, limits the practicability of the technique. This article presents a novel theoretical analysis of the effects of various nonconventional beam geometries on cooling rates and, hence, on interaction times and processing speeds, during laser surface treatment of ceramics. Initially, a commercial finite element analysis package was used to simulate the material-beam interaction conditions for various beam geometries, including rectangular, line, triangular, pi, and rhomboid. The cooling rates associated with these beam geometries were assessed and compared with those for the standard circular beam geometry. The model predicted that the rhomboid and pi beam geometries result in lower cooling rates, the line beam geometry in higher cooling rates, and the rectangular and the triangular beam geometries in similar cooling rates to those of the circular beam geometry. In particular, the model predicted that the processing speed for the rhomboid geometry had to be increased by a factor of about 5 and that for the pi geometry by a factor of about 2.5 compared to the standard circular beam geometry to produce similar cooling rates.
Rheumatoid Arthritis and Risk of Depression in South Korea
Authors: Jeon Keun Hye , Han Kyungdo , Jung Jinhyoung , Park Chun Il , Eun Yeonghee , Shin Dong Wook , Kim Hyungjin
Published: March 2024

Importance

Depression is among the most common comorbidities in rheumatoid arthritis (RA). There is a lack of data regarding the association of RA seropositivity and biologic agents with depression risk among individuals with RA.

Objective

To investigate the risk of depression following RA diagnosis among patients in South Korea.

Design, Setting, and Participants

This retrospective cohort study included 38 487 patients with RA and a comparison group of 192 435 individuals matched 1:5 for age, sex, and index date. Data were from the Korean National Health Insurance Service database. Participants were enrolled from 2010 to 2017 and were followed up until 2019. Participants who had previously been diagnosed with depression or were diagnosed with depression within 1 year after the index date were excluded. Statistical analysis was performed in May 2023.

Exposures

Seropositive RA (SPRA) was defined with the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes M05 and enrollment in the Korean Rare and Intractable Diseases program. Seronegative RA (SNRA) was defined with ICD-10 codes M06 (excluding M06.1 and M06.4) and a prescription of any disease-modifying antirheumatic drugs (DMARDs) for 270 days or more.

Main Outcomes and Measures

Newly diagnosed depression (ICD-10 codes F32 or F33).

Results

The mean (SD) age of the total study population was 54.6 (12.1) years, and 163 926 individuals (71.0%) were female. During a median (IQR) follow-up of 4.1 (2.4-6.2) years, 27 063 participants (20 641 controls and 6422 with RA) developed depression. Participants with RA had a 1.66-fold higher risk of depression compared with controls (adjusted hazard ratio [aHR], 1.66 [95% CI, 1.61-1.71]). The SPRA group (aHR, 1.64 [95% CI, 1.58-1.69]) and the SNRA group (aHR, 1.73 [95% CI, 1.65-1.81]) were associated with an increased risk of depression compared with controls. Patients with RA who used biologic or targeted synthetic DMARDs (aHR, 1.33 [95% CI, 1.20-1.47]) had a lower risk of depression compared with patients with RA who did not use these medications (aHR, 1.69 [95% CI, 1.64-1.74]).

Conclusions and Relevance

This nationwide cohort study found that both SPRA and SNRA were associated with a significantly higher risk of depression. These results suggest the importance of early screening and intervention for mental health in patients with RA.
Inventing the World: In and Around Illinois, 1960–75
Authors: Irish Sharon
Published: March 2024

Some of Lebbeus Woods's formative years were spent on the ‘flat, treeless plain’ at the University of Illinois School of Architecture and at various home and studio addresses in Urbana‐Champaign. Architectural historian Sharon Irish describes the dynamic setting of this urban stage and Woods's personal and professional preoccupations of the time.
Amine‐Rich Molecular Nodule‐Assembled Membrane Having 5 Angstrom Channels for CO2/N2 Separation
Authors: Zhao Song , Zhao Zhenyi , Zha Zhiyuan , Jiang Zhihao , Wang Zhi , Guiver Michael D.
Published: March 2024

Porous organic cages (POCs) with abundant porosity and interconnected cavities have garnered significant research attention as a distinct class of porous materials due to their potential applications in gas sorption and separation. However, the ordered arrangement of POCs to eliminate inter‐cage defects remains challenging in the assembly of molecular‐selective membranes, which greatly hinders the effectiveness of pore sieving. Here, amine‐rich molecular nodules (AMNs) are created by reduction of the porous organic cage CC2, in which the spatial structure incurs a vertex collapse into the interior of the original tetrahedral structure, which eliminates the large window of CC2. By an interfacial reaction with terephthaloyl chloride, the AMNs assemble into a cross‐linked topological network having angstrom‐scale channels for selective CO2/N2 separation. The AMN‐assembled membrane displays a high CO2 permeance of 752 GPU, a CO2/N2 selectivity of 67 at 1 bar, as well as high‐pressure resistance, operational stability, and scalable manufacture potential, which provides a cost‐effective and practical solution for developing membranes for capturing CO2 from industrial flue gas.
Dual‐Band Laser Selective Etching for Stretchable and Strain Interference‐Free Pressure Sensor Arrays
Authors: Xie Hongwei , Huang Zhenlong , Wan Jiawei , Zhou Rui , Chen Tao , Wang Yizhuo , Cheng Dong , Yang Longpeng , Ji Junjie , Jiang Yan , Wu Tailong , Liu Jing , Pan Taisong , Jiang Binbin , Zhu Jia , Yao Guang , Gao Min , Lin Yuan
Published: March 2024

Stretchable pressure sensor arrays are ideal for biomimetic electronic skin (e‐skin). However, conventional pressure sensors exhibit noticeable strain interference when stretched. This article introduces an advanced fabrication method based on dual‐band laser selective etching to create stretchable pressure sensor arrays free from strain interference. An intact sensitive film is sandwiched between the top and bottom electrodes and then etched into separate sensing cells. Silicone gel with an extremely low Young's modulus (0.157 kPa) is employed as the strain buffer layer, filling the space within sensing cells to absorb device strain during stretching. The pressure sensor arrays demonstrate exceptional interference‐free performance, with the resistance of sensing cells remaining unchanged under strains exceeding 20%. Pressure sensor arrays of 32 × 32 units are manufactured, showcasing a resistive response time of ≈40 ms during compression and 20 ms during release, along with a sensitivity of 0.7702 kPa−1 within the range of 1–70 kPa. Finally, the sensor arrays are integrated into a robotic hand as biomimetic e‐skin, coupled with deep learning algorithms, successfully identifying static and dynamic pressure distributions and achieving an average precision rate of over 99% in recognizing 2D shapes and objects.
Cascade Cyclization/Amination of para‐Quinone Methides with β‐Ketodinitriles: Synthesis of Polysubstituted Furans
Authors: Fan Liyong , Zhu Longzhi , Shang Wenli , Yin Mingming , Xiong Biquan , Xie Wuxing , Cao Fan , Liu Yu , Chen Yi , Qiu Renhua
Published: March 2024

A protocol for the synthesis of trisubstituted furans via phosphoric acid‐catalyzed regioselective cascade cyclization/amination of para‐quinone methides (p‐QMs) with β‐ketodinitriles has been disclosed for the first time. Various kinds of p‐QMs and β‐ketodinitriles can effectively produce the desired polysubstituted furan derivatives in 64–95% yields, demonstrating high atomic economy and their application in the construction of polysubstituted furan heterocycles. Preliminary biological activity assay suggests that these furans have potential anticancer activities.
Tetrafluoropyridinyl Thiolate as a Tool for Enabling Photoredox Alkylation of 1,2,4‐Oxadiazoles
Authors: Frumkin Alexander E. , Levin Vitalij V. , Dilman Alexander D.
Published: March 2024

A method for the radical functionalization of 1,2,4‐oxadiazoles using alkyl halides as precursors of radicals is described. The reaction efficiency is determined by potassium tetrafluoropyridinyl thiolate additive, which plays dual role. First, the thiolate converts alkyl halides into more reactive fluorinated aryl sulfides, which undergo photoredox activation of the C−S bond. Second, the thiolate decreases the unproductive loss of alkyl radicals by converting them back to the sulfides.
Friends without benefits: Extensive cytotype sympatry and polyploid persistence in an African geophyte
Authors: Vaz de Sousa Damian , Greve Michelle , Oberlander Kenneth C.
Published: March 2024

Premise

Polyploidy is a major factor in plant adaptation and speciation. Multiple mechanisms contribute to autopolyploid frequency within populations, but uncertainties remain regarding mechanisms that facilitate polyploid establishment and persistence. Here we aimed to document and predict cytotype distributions of Oxalis obliquifolia Steud. ex A. Rich. across Gauteng, South Africa, and test for evidence of possible mechanisms, including morphological, phenological, and reproductive traits, that may potentially facilitate polyploid persistence.

Methods

Over 320 O. obliquifolia plants from 25 sites were cytotyped using flow cytometry, and DNA ploidy was confirmed using meiotic chromosome squashes. Cytotypes were mapped and correlations with abiotic variables assessed using ordinations. To assess morphological and phenological associations with cytotype, we grew multiple cytotypes in a common garden, measured phenotypic traits and compared them using linear models and discriminant analyses. Intercytotype reproductive isolation was assessed using crossing experiments, and AMOVAs based on ITS DNA sequences tested for cytogeographic structure.

Results

Six cytotypes were identified, and most sites had multiple cytotypes. Abiotic variables were not predictive of cytotype distribution. A clear gigas effect was present. Differences in flower size and phenology suggested pollinator interactions could play a role in polyploid persistence. Intercytotype crosses produced seed at low frequency. DNA data suggested diploids and polyploids were largely reproductively isolated in situ, and polyploidization events were not frequent enough to explain high cytotype sympatry.

Conclusions

Diploids and polyploids are behaving as separate species, despite little observable niche differentiation and non‐zero potential intercytotype seed set. Tests on biotic interactions and intercytotype F1 fitness may provide insights into diploid and polyploid coexistence.
Thermal vs. Visible‐Light Photoredox‐Catalyzed Cascade Radical Cyclization Involving SO2 Fixation to Access 6‐Alkylsulfonylmethyl Phenanthridines
Authors: Sahu Tonish Kumar , Vishwakarma Abhaykumar , Kumar Vidyanshu , Khan Rahimuddin , Khan Tabrez
Published: March 2024

Convenient access to 6‐alkylsulfonylmethyl phenanthridines has been demonstrated both under non‐catalytic thermal and visible‐light photoredox‐catalyzed conditions. A cascade of radical cyclization is triggered by the exposure of biphenyl vinyl azides to the in‐situ generated alkyl sulfonyl radicals from 4‐substituted Hanztsch esters in the presence of an SO2 surrogate. Transition metal‐free, mild reaction conditions, and broad substrate scope constitute some of the highlights of the approach. Also, the synthetic utility of the accessed 6‐alkylsulfonylmethyl phenanthridines has been demonstrated.
The effects of feeding frequency on jaw loading in two lemur species
Authors: Yamashita Nayuta , Flowers Nina , Fogaça Mariana Dutra
Published: March 2024

Objectives

Studies on oral processing are often snapshots of behaviors that examine feeding through individual bouts. In this study, we expand on our previous work comparing bite/chew variables per feeding bout to summed daily biting, chewing, and food intake to interpret loading that could have potential morphological effects.

Materials and Methods

We observed sympatric Lemur catta and Propithecus verreauxi over two field seasons in the dry forest of Bezà Mahafaly Special Reserve in southwestern Madagascar. Bite and chew rates determined from videos filmed during observations were multiplied with time spent feeding on specific foods during focal follows to calculate daily values for each feeding bout. Food mechanical properties (FMPs) were tested on dietary items with a portable tester. We contrasted daily bite/chew numbers and intake with FMPs, species, season, and food shape.

Results

Daily bite and chew numbers increased with maximum, but not average, food toughness. Daily intake decreased with average and maximum toughness. Season had a strong effect on daily bites and chews, but not on intake. Food shape influenced intake and total bite and chew numbers. The lemur species did not differ in our models.

Discussion

Maximum food toughness impacted feeding behaviors and intake, which is consistent with higher loads having a greater effect on morphology. In contrast to feeding per bout, cumulative biting and chewing did not differ between species; taking feeding frequency into consideration affects interpretation of jaw loading. Finally, biting, as much as chewing, may generate strains that impact morphology.
Diffusion MRI relates to plasma Aβ42/40 in PET negative participants without dementia
Authors: DeSimone Jesse C. , Wang Wei‐en , Loewenstein David A. , Duara Ranjan , Smith Glenn E. , McFarland Karen N. , Armstrong Melissa J. , Weber Darren M. , Barker Warren , Coombes Stephen A. , Vaillancourt David E.
Published: March 2024

INTRODUCTION

Magnetic resonance imaging (MRI) biomarkers are needed for indexing early biological stages of Alzheimer's disease (AD), such as plasma amyloid‐β (Aβ42/40) positivity in Aβ positron emission tomography (PET) negative individuals.

METHODS

Diffusion free‐water (FW) MRI was acquired in individuals with normal cognition (NC) and mild cognitive impairment (MCI) with Aβ plasma‐/PET‐ (NC = 22, MCI = 60), plasma+/PET‐ (NC = 5, MCI = 20), and plasma+/PET+ (AD dementia = 21) biomarker status. Gray and white matter FW and fractional anisotropy (FAt) were compared cross‐sectionally and the relationships between imaging, plasma and PET biomarkers were assessed.

RESULTS

Plasma+/PET‐ demonstrated increased FW (24 regions) and decreased FAt (66 regions) compared to plasma‐/PET‐. FW (16 regions) and FAt (51 regions) were increased in plasma+/PET+ compared to plasma+/PET‐. Composite brain FW correlated with plasma Aβ42/40 and p‐tau181.

DISCUSSION

FW imaging changes distinguish plasma Aβ42/40 positive and negative groups, independent of group differences in cognitive status, Aβ PET status, and other plasma biomarkers (i.e., t‐tau, p‐tau181, glial fibrillary acidic protein, neurofilament light).

Highlights

Plasma Aβ42/40 positivity is associated with brain microstructure decline.

Plasma+/PET‐ demonstrated increased FW in 24 total GM and WM regions.

Plasma+/PET‐ demonstrated decreased FAt in 66 total GM and WM regions.

Whole‐brain FW correlated with plasma Aβ42/40 and p‐tau181 measures.

Plasma+/PET‐ demonstrated decreased cortical volume and thickness.
MoS2 Hollow Multishelled Nanospheres Doped Fe Single Atoms Capable of Fast Phase Transformation for Fast‐charging Na‐ion Batteries
Authors: Zhang Hui , Zhang Shaocheng , Guo Baiyu , Yu Li‐juan , Ma Linlin , Hou Baoxiu , Liu Haiyan , Zhang Shuaihua , Wang Jiangyan , Song Jianjun , Tang Yongfu , Zhao Xiaoxian
Published: March 2024

Low Na+ and electron diffusion kinetics severely restrain the rate capability of MoS2 as anode for sodium‐ion batteries (SIBs). Slow phase transitions between 2H and 1T, and from NaxMoS2 to Mo and Na2S as well as the volume change during cycling, induce a poor cycling stability. Herein, an original Fe single atom doped MoS2 hollow multishelled structure (HoMS) is designed for the first time to address the above challenges. The Fe single atom in MoS2 promotes the electron transfer, companying with shortened charge diffusion path from unique HoMS, thereby achieving excellent rate capability. The strong adsorption with Na+ and self‐catalysis of Fe single atom facilitates the reversible conversion between 2H and 1T, and from NaxMoS2 to Mo and Na2S. Moreover, the buffering effect of HoMS on volume change during cycling improves the cyclic stability. Consequently, the Fe single atom doped MoS2 quadruple‐shelled sphere exhibits a high specific capacity of 213.3 mAh g−1 at an ultrahigh current density of 30 A g−1, which is superior to previously‐reported results. Even at 5 A g−1, 259.4 mAh g−1 (83.68 %) was reserved after 500 cycles. Such elaborate catalytic site decorated HoMS is also promising to realize other “fast‐charging” high‐energy‐density rechargeable batteries.
A P2/P3 Biphasic Layered Oxide Composite as a High‐Energy and Long‐Cycle‐Life Cathode for Potassium‐Ion Batteries
Authors: Duan Liping , Shao Caoyang , Liao Jiaying , Song Lili , Zhang Yingna , Li Renke , Guo Shaohua , Zhou Xiaosi , Zhou Haoshen
Published: March 2024

Layered transition metal oxides are extensively considered as appealing cathode candidates for potassium‐ion batteries (PIBs) due to their abundant raw materials and low cost, but their further implementations are limited by slow dynamics and impoverished structural stability. Herein, a layered composite having a P2 and P3 symbiotic structure is designed and synthesized to realize PIBs with large energy density and long‐term cycling stability. The unique intergrowth of P2 and P3 phases in the obtained layered oxide is plainly characterized by X‐ray diffraction refinement, high‐angle annular dark field and annular bright field‐scanning transmission electron microscopy at atomic resolution, and Fourier transformation images. The synergistic effect of the two phases of this layered P2/P3 composite is well demonstrated in K+ intercalation/extraction process. The as‐prepared layered composite can present a large discharge capacity with the remarkable energy density of 321 Wh kg−1 and also manifest excellent capacity preservation after 600 cycles of K+ uptake/removal.
Unveiling the physical properties predictive of oil binding capacity in an interesterified palm‐based fat
Authors: Marsh Melissa Abigail , Bean Brennan , Maleky Farnaz , Martini Silvana
Published: March 2024

This paper identifies physical properties of an interesterified palm‐based fat (EIEPO) that predict oil binding capacity (OBC). A 100% EIEPO sample, 50% EIEPO sample diluted with 50% soybean oil (SBO), and a 20% EIEPO sample diluted with 80% SBO were used to test how saturation level impacts OBC. All samples were crystallized using either a fast (6.4°C/min) or slow (0.1°C/min) cooling rate as well as with or without the application of high‐intensity ultrasound (HIU; 20 kHz) to generate a wide range of physical properties. Immediately after crystallization, the sample's physical properties, including crystal microstructure, solid fat content (SFC), viscoelasticity (G′, G″, and δ), melting behavior, hardness, and OBC (centrifuge method) were quantified. The samples were then stored for 48 h at 22 and 5°C and the aforementioned physical properties were measured again, with one additional measurement for the samples stored at 5°C—OBC using a filter paper method (OBCp). The results indicate that OBC can be optimized in a palm‐based fat by modifying the physical properties which was achieved via the processing conditions. Both measurements of OBC were significantly correlated with SFC, hardness, δ, and enthalpy. A model was developed to predict a sample's OBCc using the following dominant variables—SFC, hardness, peak temperature, enthalpy, and the number of crystals. These results suggest that OBC can be predicted using a sample's SFC, hardness, peak temperature, enthalpy, and number of crystals and that SFC, hardness, and enthalpy are main drivers of OBC.
Electro‐bio‐mechanical behavior of graphite nanoplatelets–silicone rubber‐based composites for wearable electronic systems
Authors: Azam Siraj , Kumar Vineet , Park Sang‐Shin
Published: March 2024

Adding graphite nanoplatelets (GNP) into silicone rubber (SR) composites have shown significant potential for wearable electronics, where electrical, mechanical, and tribological properties play a crucial role. This study investigates the effects of incorporating graphite nanoplatelets (GNP) into SR composites and their impact on these key properties. Solution mixing of SR and GNP was performed to confirm good dispersion of the GNP within the SR matrix. The results showed improved tensile strength and modulus while stabilizing the flexibility and stretchability required for wearable electronics. For example, the tensile strength of the composites was 0.86 MPa (control) and increased to 1.18 MPa (5 part per hundred rubber [phr] GNP), and 1.55 MPa (15 phr GNP). Similarly, the stretchability was 177 % (control) and increased to 190 % (5 phr GNP), and 184 % (15 phr GNP). Moreover, the electro‐mechanical tests were studied and the output voltage for the samples were 0.28 milli‐volt (mV) (5 phr GNP), and 0.31 mV (15 phr GNP). Similarly, the output voltage generation was studied through human motions. The results obtained from these biomechanical motions such as thumb pressing were 0.7 mV (5 phr GNP), and 2.7 mV (15 phr GNP). The study finds the potential of GNP‐SR composites as multifunctional materials such as wearable electronics. Overall, this research guides the development of advanced wearable devices, soft robotics, and bio‐inspired electronics with improved performance and durability.
Correlation between COVID‐19 infection and fetal situs inversus
Authors: Qiu Shuo , Wu Shuang , Yin Ranran , Wang Bo , Wu Hongying
Published: March 2024

Background

Situs inversus is a rare congenital condition, defined by the mirror‐image transposition of the abdominothoracic organs. It is linked to an increased risk of different disorders, for example, congenital heart defects and primary ciliary dyskinesia. Recently, some reports have been on the increased incidence of situs inversus after the COVID‐19 pandemic.

Objectives

To investigate the association between maternal COVID‐19 infection and fetal situs inversus occurrence risk.

Methods

All pregnant women who underwent fetal ultrasound examinations at Jinan Maternal and Child Health Hospital from January to May of 2022 and 2023 were recruited. A chi‐square test was conducted to assess the association of maternal COVID‐19 infection with the incidence rate of fetal situs inversus.

Results

A total of 8381 patients, including 25 with situs inversus fetuses were recruited. A total of 3956 patients had COVID‐19, while 4400 did not. Among 25 mothers with situs inversus fetuses, 22 had COVID‐19 and 3 without recent infection. Our analysis showed a strong link between COVID‐19 and a higher risk of fetus situs inversus (P < .001, odds ratio 8.196).

Conclusion

Maternal COVID‐19 infection in the early stages of the pregnancy is associated with an increased risk of fetal situs inversion occurrence. Therefore, further research in this field seems necessary.
Preclinical Evaluation of the Reversible Monoacylglycerol Lipase PET Tracer (R)‐[11C]YH132: Application in Drug Development and Neurodegenerative Diseases
Authors: He Yingfang , Delparente Aro , Jie Caitlin V. M. L , Keller Claudia , Humm Roland , Heer Dominik , Collin Ludovic , Schibli Roger , Gobbi Luca , Grether Uwe , Mu Linjing
Published: March 2024

Monoacylglycerol lipase (MAGL) plays a crucial role in the degradation of 2‐arachidonoylglycerol (2‐AG), one of the major endocannabinoids in the brain. Inhibiting MAGL could lead to increased levels of 2‐AG, which showed beneficial effects on pain management, anxiety, inflammation, and neuroprotection. In the current study, we report the characterization of an enantiomerically pure (R)‐[11C]YH132 as a novel MAGL PET tracer. It demonstrates an improved pharmacokinetic profile compared to its racemate. High in vitro MAGL specificity of (R)‐[11C]YH132 was confirmed by autoradiography studies using mouse and rat brain sections. In vivo, (R)‐[11C]YH132 displayed a high brain penetration, and high specificity and selectivity toward MAGL by dynamic PET imaging using MAGL knockout and wild‐type mice. Pretreatment with a MAGL drug candidate revealed a dose‐dependent reduction of (R)‐[11C]YH132 accumulation in WT mouse brains. This result validates its utility as a PET probe to assist drug development. Moreover, its potential application in neurodegenerative diseases was explored by in vitro autoradiography using brain sections from animal models of Alzheimer's disease and Parkinson's disease.
Synthesis and Macrodomain Binding of Gln‐carba‐ADPr‐peptide
Authors: Engelsma Sander B. , Nardozza Aurelio Pio , de Saint Aulaire Pieter , Overkleeft Herman S. , van der Marel Gijsbert A. , Ladurner Andreas G. , Filippov Dmitri V.
Published: March 2024

Mono‐ADP‐ribosylation is a dynamic post‐translational modification (PTM) with important roles in cell signalling. This modification occurs on a wide variety of amino acids, and one of the canonical modification sites within proteins is the side chain of glutamic acid. Given the transient nature of this modification (acylal linkage) and the high sensitivity of ADP‐ribosylated glutamic acid, stabilized isosteres are required for structural and biochemical studies. Here, we report the synthesis of a mimic of ADP‐ribosylated peptide derived from histone H2B that contains carba‐ADP‐ribosylated glutamine as a potential mimic for Glu‐ADPr. We synthesized a cyclopentitol‐ribofuranosyl derivative of 5′‐phosphoribosylated Fmoc‐glutamine and used this in the solid‐phase synthesis of the carba‐ADPr‐peptide mimicking the ADP‐ribosylated N‐terminal tail of histone H2B. Binding studies with isothermal calorimetry demonstrate that the macrodomains of human MacroD2 and TARG1 bind to carba‐ADPr‐peptide in the same way as ADPr‐peptides containing the native ADP‐riboside moiety connected to the side chain of glutamine in the same peptide sequence.
Conversion of β‐1,6‐Glucans to Gentiobiose using an endo‐β‐1,6‐Glucanase PsGly30A from Paenibacillus sp. GKG
Authors: Plakys Gediminas , Urbelienė Nina , Urbelis Gintaras , Vaitekūnas Justas , Labanauskas Linas , Mažonienė Edita , Meškys Rolandas
Published: March 2024

A plethora of di‐ and oligosaccharides isolated from the natural sources are used in food and pharmaceutical industry. An enzymatic hydrolysis of fungal cell wall β‐glucans is a good alternative to produce the desired oligosaccharides with different functionalities, such as the flavour enhancer gentiobiose. We have previously identified PsGly30A as a potential yeast cell wall degrading β‐1,6‐glycosidase. The aim of this study is to characterise the PsGly30A enzyme, a member of the GH30 family, and to evaluate its suitability for the production of gentiobiose from β‐1,6‐glucans. An endo‐β‐1,6‐glucanase PsGly30A encoding gene from Paenibacillus sp. GKG has been cloned and overexpressed in Escherichia coli. The recombinant enzyme has been active towards pustulan and yeast β‐glucan, but not on laminarin from the Laminaria digitata, confirming the endo‐β‐1,6‐glucanase mode of action. The PsGly30A shows the highest activity at pH 5.5 and 50 °C. The specific activity of PsGly30A on pustulan (1262±82 U/mg) is among the highest reported for GH30 β‐1,6‐glycosidases. Moreover, gentiobiose is the major reaction product when pustulan, yeast β‐glucan or yeast cell walls have been used as a substrate. Therefore, PsGly30A is a promising catalyst for valorisation of the yeast‐related by‐products.
Paraganglioma at the cerebellopontine angle: A case report and review of literature
Authors: Akhtar Nadeem , Shahid Fatimah , Ali Alishba Shezal , Muhammad Qurat Ul Ain , Azam Noor Mahal , Dhakal Bishal , Ibrahim Muhammad , Nadeem Nehal
Published: March 2024

Key Clinical Message

Paragangliomas (PGLs) are rare neuroendocrine tumors. Sometimes, these tumors secrete excessive catecholamines, which results in the manifestations of various signs and symptoms, usually with a triad of hypertension, tachycardia, and headache. We report the case of a 42‐year‐old woman presenting with uncontrolled hypertension, right facial palsy, vomiting, and disturbed gait. Diagnosis for PGL was confirmed on postoperative histological examination of the excised mass and correlated with preoperative clinical and radiological findings. Tumor excision was done via a suboccipital craniotomy approach. Our case presents the typically severe features of a jugulotympanic PGL, but most importantly, it highlights the necessity of biochemical diagnosing, thorough probing of the causes of hypertension, and a multi‐disciplinary approach in dealing with these tumors. Moreover, the case emphasizes necessitating the use of preoperative embolization in vascular tumors of the head and neck to avoid a hemorrhagic crisis during surgery. Unfortunately, due to a lack of adequate hospital funds, the surgeon had to proceed without preoperative embolization. Despite such a risk, the excision was a success.
Rice cake ileus
Authors: Imataki Osamu , Uemura Makiko
Published: March 2024

Key Clinical Message

Japanese rice cake, mochi, is made from glutinous rice, a very sticky food. Mochi is a popular preserved food during the New Year holiday celebration. However, mochi can be hazardous because of lethal choking or ileus.
Testicular neuroendocrine tumor in a 32‐year‐old man: A case report
Authors: Dehghaniathar Reza , Moradi Asaad , Emtiazi Nikoo
Published: March 2024

Key Clinical Message

A 32‐year‐old male with painful scrotal swelling who underwent radical orchiectomy and was diagnosed with a testicular neuroendocrine tumor. Determining whether testicular neuroendocrine tumor is primary or metastasis from another origin is crucial.

Testicular neuroendocrine tumors (TNET) are one of the rarest human neoplasms, with about 132 identified cases until 2015. Testicular neuroendocrine tumors are frequently manifest with painless scrotal swelling or mass. In this study, we present a 32‐year‐old male with a chief complaint of painful progressive swelling of the right testicle without any history of trauma. All laboratory tests were within the normal range. Ultrasound revealed two hyper‐vascular masses in the right testicle. Computed tomography was performed, and patients had no evidence of metastases. The patient underwent right radical orchiectomy, and a histopathological examination diagnosed the specimen with a well‐differentiated testicular neuroendocrine tumor. Because of the rarity of TNET, there are many controversial issues in the treatment, especially in cases with metastatic TNET. Determining whether testicular neuroendocrine tumor is primary or metastasis from another origin is crucial. Further studies are required to achieve optimum treatment for TNET.
An unusual cause of inguinal swelling: Primary synovial osteochondromatosis
Authors: Limaiem Faten , Gharbi Mohamed Amine , Bouzidi Ramzi
Published: March 2024

Key Clinical Message

Inguinal swelling should raise suspicion for hip joint osteochondromatosis. Early recognition, accurate diagnosis, and prompt surgical intervention are essential for optimizing patient outcomes.
Palladium‐Catalyzed C−H Alkenylation of α‐Aryl Alkyl Nitriles
Authors: Wang Jingwen , Tao Zhonglin
Published: March 2024

A direct α‐alkenylation of nitrile compounds was realized with a palladium complex. This method exhibited excellent tolerance toward a variety of α‐aryl alkyl nitriles and vinyl bromides, leading to the formation of a series of α‐quaternary nitriles containing vinyl groups. Further manipulations of the obtained products were demonstrated, highlighting the potential synthetic utility of this method.
Photochemical Carbocatalysis: Fullerene‐, Carbon Nanotube‐ or Graphene‐Based Metal‐Free Photocatalysts for Organic Transformations
Authors: Chronopoulos Demetrios D. , Otyepka Michal , Kokotos Christoforos G.
Published: March 2024

Synthetic photochemistry is a research field, where organic transformations are promoted by the presence of photoactive species, under light irradiation. In particular, the sub‐field of photoorganocatalysis, where organic molecules are used as photocatalysts, has been launched as a “green” and sustainable approach. Carbon allotrope nanostructures (CANs) and their derivatives exhibit unique photophysical and photochemical properties, which have been exploited for the preparation of efficient metal‐free and sustainable photocatalytic systems. This review summarizes the progress on the field of photochemical carbocatalysis, presenting the achievements by fullerene‐, carbon nanotube‐ and graphene‐based nanomaterials. Additionally, future prospects for CAN‐based nanomaterials as photochemical promoters for organic transformations are also mentioned.