Search

The protein therapeutics market, including antibody and fusion proteins, has experienced steady growth over the past decade, underscoring the importance of optimizing amino acid sequences. In our previous study, we developed a fusion protein, R31, which combines retinol-binding protein (RBP) with albumin domains IIIA and IB, linked by a sequence (AAAA), and includes an additional disulfide bond (N227C-V254C) in IIIA. This fusion protein effectively inhibited hepatic stellate cell activation. In this study, we further optimized the sequence. The G176K mutation at the C-terminus of RBP altered the initiation site of the first α-helix in domain IIIA, shifting it from P182 to K176, and promoted polar interactions between K176 and adjacent residues, enhancing the rigidity of the RBP/IIIA interface. The introduction of an additional disulfide bond (V231C/Y250C) connecting helices 3 and 4 in IIIA resulted in a three-fold increase in productivity and a 2 °C improvement in thermal stability compared to R31. Furthermore, combining the G176K mutation with V231C/Y250C further enhanced both productivity and anti-fibrotic activity. These findings suggest that the enhanced stability of domain IIIA, conferred by V231C/Y250C, along with the increased rigidity of the RBP/IIIA interface, optimizes interdomain distance and alignment, facilitating proper protein folding. [ABSTRACT FROM AUTHOR]

The pursuit of high energy densities propels the design of next‐generation nickel‐based layered oxide cathodes. The utilization of low‐cobalt, ultrahigh‐nickel layered oxide cathodes, and the extension of operating voltages promise enhanced energy density. However, stability and safety face challenges associated with nickel content, including structural degradation, lattice oxygen evolution, and thermal instability. In this study, a promising strategy of Al and Nb dual‐bulk‐doping is presented in high‐Ni cathode materials of LiNi0.96Co0.04O2 (NC) to stabilize the bulk structure, suppress oxygen release, and attain superior electrochemical performance at high voltages. The introduction of Al and Nb effectively raises the migration energy of Ni2+ into Li sites and stabilizes lattice oxygen through strengthened Al─O and Nb─O bonds. Furthermore, the substitution of high‐valence Nb ions reduces the charge depletion of lattice oxygen and induces an ordered microstructure. The Al and Nb dual‐bulk‐doping strategy mitigates strain and stress associated with the H2↔H3 phase transition, reducing the generation and propagation of microcracks. The resulting Li(Ni0.96Co0.04)0.985Al0.01Nb0.005O2 (NCAN) cathode exhibits superior cycling stability, with a capacity retention of 77.8% after 300 cycles, even when operating at a high‐voltage of 4.4 V, outperforming the NC (48.5%). This work provides a promising perspective for developing high‐voltage and high‐Ni cathode materials. [ABSTRACT FROM AUTHOR]

Indium–salen complexes with electron‐donating 9,9‐dimethyl‐9,10‐dihydroacridine (DMAC) groups at positions 4 (DMACIn1) and 4 and 6 (DMACIn2) were synthesized and characterized to investigate the effect of the substituents number and structural rigidity on photophysical properties. The single crystal structure of DMACIn1 revealed highly twisted arrays (83–89°) between the DMAC groups and salen moieties and a nearly square‐pyramidal geometry around the indium center. Both complexes exhibited green fluorescence in toluene at 298 K and in rigid states (in toluene at 77 K and in a film), which originates from intramolecular charge transfer (ICT) transitions. The absolute photoluminescence quantum yields (PLQYs) of DMACIn1 and DMACIn2 were low in solution but high in the rigid states. The film‐state PLQY of DMACIn2 (59.5%) was more than five‐fold higher than that of DMACIn1 (11.1%). A similar result was observed in toluene at 77 K. These findings were rationalized in terms of the beneficial effects of structural rigidity and higher number of DMAC donors on ICT‐based radiative decay. The experimental results agreed with those of computational studies. [ABSTRACT FROM AUTHOR]

Shear walls are one of the most popular lateral load-resisting methods used in high-rise structures. Major design factors against structural collapse in RC buildings include lateral stresses (wind, seismic). Notably, in Bangladesh, shear walls are strategically integrated into various locations to enhance both the structural rigidity and aesthetic appeal of buildings. The optimal placement for a building's shear wall is not specified in the Bangladesh National Building Code (BNBC).This study addresses this gap by thoroughly analyzing sixteen structures according to the guidelines of four different building codes. Four buildings with different shear wall locations, such as without shear wall, the shear wall at the periphery symmetrically, the shear wall at the corner symmetrically, and the box shear wall at the core of the building have been analyzed by structural analysis and design software ETABS. By contrasting the displacement, narrative drift, story shear, and story stiffness, the outcomes are evaluated. According to the calculations, the best way to lessen displacement and story drift is to symmetrically put a shear wall at the centre of the structure. The structure may be stiffer at the center than it is elsewhere due to the symmetrical shear wall. The study's conclusions could serve as a useful guide for Bangladeshi engineers in practice.

In contemporary urban environments, the scarcity of space and the prevalence of apartment living necessitate extensive excavation to secure adequate space and appropriate infrastructure for most construction projects. The influence of the structural rigidity of adjacent buildings on controlling ground displacement induced by excavation is critically important yet underexplored. This study investigates the effect of the rigidity of neighboring buildings' structural elements on excavation by analyzing nearly all relevant components. The results show that the structural rigidity of adjacent buildings significantly impacts the horizontal deformations of the excavation wall and the positions of maximum horizontal deformation in both the excavation wall and the ground beneath the structures. As the building's rigidity increases, the maximum horizontal deformations of the wall occur at greater depths within the excavation. Additionally, increased rigidity causes the location of maximum horizontal deformations of the ground beneath the structure, near the excavation, to shift towards the center of the building. Furthermore, as the building length increases, the depth at which maximum horizontal deformation occurs also increases. However, the location of deformation beneath the adjacent building is independent of the building's width and does not change with variations in the building's length.

Abstract Background Breast cancer (BrCa) is a predominant malignancy, with metastasis occurring in one in eight patients, nearly half of which target the bone, leading to serious complications such as pain, fractures, and compromised mobility. Structural rigidity, crucial for bone strength, becomes compromised with osteolytic lesions, highlighting the vulnerability and increased fracture risk in affected areas. Historically, two-dimensional radiographs have been employed to predict these fracture risks; however, their limitations in capturing the three-dimensional structural and material changes in bone have raised concerns. Recent advances in CT-based Structural Rigidity Analysis (CTRA), offer a promising, more accurate non-invasive 3D approach. This study aims to assess the efficacy of CTRA in monitoring osteolytic lesions’ progression and response to therapy, suggesting its potential superiority over existing methodologies in guiding treatment strategies. Methods Twenty-seven female nude rats underwent femoral intra-medullary inoculation with MDA-MB-231 human breast cancer cells or saline control. They were divided into Control, Cancer Control, Ibandronate, and Paclitaxel groups. Osteolytic progression was monitored weekly using biplanar radiography, quantitative computed tomography (QCT), and dual-energy X-ray absorptiometry (DEXA). CTRA was employed to predict fracture risk, normalized using the contralateral femur. Statistical analyses, including Kruskal-Wallis and ANOVA, assessed differences in outcomes among groups and over time. Results Biplanar radiographs showed treatment benefits over time; however, only certain time-specific differences between the Control and other treatment groups were discernible. Notably, observer subjectivity in X-ray scoring became evident, with significant inter-operator variations. DEXA measurements for metaphyseal Bone Mineral Content (BMC) did not exhibit notable differences between groups. Although diaphyseal BMC highlighted some variance, it did not reveal significant differences between treatments at specific time points, suggesting a limited ability for DEXA to differentiate between treatment effects. In contrast, the CTRA consistently demonstrated variations across different treatments, effectively capturing bone rigidity changes over time, and the axial- (EA), bending- (EI), and torsional rigidity (GJ) outcomes from the CTRA method successfully distinguished differences among treatments at specific time points. Conclusion Traditional approaches, such as biplanar radiographs and DEXA, have exhibited inherent limitations, notably observer bias and time-specific inefficacies. Our study accentuates the capability of CTRA in capturing real-time, progressive changes in bone structure, with the potential to predict fractures more accurately and provide a more objective analysis. Ultimately, this innovative approach may bridge the existing gap in clinical guidelines, ushering in enhanced Clinical Decision Support Tool (CDST) for both surgical and non-surgical treatments.

Shear walls are one of the most popular lateral load-resisting methods used in high-rise structures. Major design factors against structural collapse in RC buildings include lateral stresses (wind, seismic). Notably, in Bangladesh, shear walls are strategically integrated into various locations to enhance both the structural rigidity and aesthetic appeal of buildings. The optimal placement for a building's shear wall is not specified in the Bangladesh National Building Code (BNBC).This study addresses this gap by thoroughly analyzing sixteen structures according to the guidelines of four different building codes. Four buildings with different shear wall locations, such as without shear wall, the shear wall at the periphery symmetrically, the shear wall at the corner symmetrically, and the box shear wall at the core of the building have been analyzed by structural analysis and design software ETABS. By contrasting the displacement, narrative drift, story shear, and story stiffness, the outcomes are evaluated. According to the calculations, the best way to lessen displacement and story drift is to symmetrically put a shear wall at the centre of the structure. The structure may be stiffer at the center than it is elsewhere due to the symmetrical shear wall. The study's conclusions could serve as a useful guide for Bangladeshi engineers in practice. [ABSTRACT FROM AUTHOR]

Background: Breast cancer (BrCa) is a predominant malignancy, with metastasis occurring in one in eight patients, nearly half of which target the bone, leading to serious complications such as pain, fractures, and compromised mobility. Structural rigidity, crucial for bone strength, becomes compromised with osteolytic lesions, highlighting the vulnerability and increased fracture risk in affected areas. Historically, two-dimensional radiographs have been employed to predict these fracture risks; however, their limitations in capturing the three-dimensional structural and material changes in bone have raised concerns. Recent advances in CT-based Structural Rigidity Analysis (CTRA), offer a promising, more accurate non-invasive 3D approach. This study aims to assess the efficacy of CTRA in monitoring osteolytic lesions' progression and response to therapy, suggesting its potential superiority over existing methodologies in guiding treatment strategies. Methods: Twenty-seven female nude rats underwent femoral intra-medullary inoculation with MDA-MB-231 human breast cancer cells or saline control. They were divided into Control, Cancer Control, Ibandronate, and Paclitaxel groups. Osteolytic progression was monitored weekly using biplanar radiography, quantitative computed tomography (QCT), and dual-energy X-ray absorptiometry (DEXA). CTRA was employed to predict fracture risk, normalized using the contralateral femur. Statistical analyses, including Kruskal-Wallis and ANOVA, assessed differences in outcomes among groups and over time. Results: Biplanar radiographs showed treatment benefits over time; however, only certain time-specific differences between the Control and other treatment groups were discernible. Notably, observer subjectivity in X-ray scoring became evident, with significant inter-operator variations. DEXA measurements for metaphyseal Bone Mineral Content (BMC) did not exhibit notable differences between groups. Although diaphyseal BMC highlighted some variance, it did not reveal significant differences between treatments at specific time points, suggesting a limited ability for DEXA to differentiate between treatment effects. In contrast, the CTRA consistently demonstrated variations across different treatments, effectively capturing bone rigidity changes over time, and the axial- (EA), bending- (EI), and torsional rigidity (GJ) outcomes from the CTRA method successfully distinguished differences among treatments at specific time points. Conclusion: Traditional approaches, such as biplanar radiographs and DEXA, have exhibited inherent limitations, notably observer bias and time-specific inefficacies. Our study accentuates the capability of CTRA in capturing real-time, progressive changes in bone structure, with the potential to predict fractures more accurately and provide a more objective analysis. Ultimately, this innovative approach may bridge the existing gap in clinical guidelines, ushering in enhanced Clinical Decision Support Tool (CDST) for both surgical and non-surgical treatments. [ABSTRACT FROM AUTHOR]

The versatile basic structure of piperazine allows for the development and production of newer bioactive molecules that can be used to treat a wide range of diseases. Piperazine derivatives are unique and can easily be modified for the desired pharmacological activity. The two opposing nitrogen atoms in a six‐membered piperazine ring offer a large polar surface area, relative structural rigidity, and more acceptors and donors of hydrogen bonds. These properties frequently result in greater water solubility, oral bioavailability, and ADME characteristics, as well as improved target affinity and specificity. Various synthetic protocols have been reported for piperazine and its derivatives. In this review, we focused on recently published synthetic protocols for the synthesis of the piperazine and its derivatives. The structure–activity relationship concerning different biological activities of various piperazine‐containing drugs has also been highlighted to provide a good understanding to researchers for future research on piperazines. [ABSTRACT FROM AUTHOR]

The lightweight fabrication of thin-walled cabin sections is popular for advanced ships, and the dimensional tolerance generated by welding buckling significantly influences the fabrication accuracy and schedule with poststraightening. A typical thin section employed in the superstructure of a high-tech passenger ship is considered the research object. Conventional fabrication procedures and welding conditions were examined beforehand with combined thermal elastic-plastic and elastic FE computations based on the theory of welding inherent deformation, while welding buckling was represented with identical behavior compared with fabrication observation. Actually, there are usually two methods to prevent welding buckling with advanced fabrication. Stiffeners with optimized geometrical features and excellent elasticity moduli were assembled to enhance the rigidity of the ship thin section, and less welding inherent deformation with advanced welding methods can be employed to reduce mechanical loading. Computational results show that either less in-plane welding inherent strain or higher structural rigidity can reduce the magnitude of welding-induced buckling, and avoid the generation of welding-induced buckling during the lightweight fabrication. [ABSTRACT FROM AUTHOR]

Accurate localization from Cyber-Physical Systems (CPS) is a critical enabling technology for context-aware applications and control. As localization plays an increasingly safety-critical role, location systems must be able to identify and eliminate faulty measurements to prevent dangerously inaccurate localization. In this article, we consider the range-based localization problem and propose a method to detect coordinated adversarial corruption on anchor positions and distance measurements. Our algorithm, Gordian, rapidly finds attacks by identifying geometric inconsistencies at the graph level without requiring assumptions about hardware, ranging mechanisms, or cryptographic protocols. We give necessary conditions for which attack detection is guaranteed to be successful in the noiseless case, and we use that intuition to extend Gordian to the noisy case where fewer guarantees are possible. In simulations generated from real-world sensor noise, we empirically show that Gordian's trilateration counterexample generation procedure enables rapid attack detection even for combinatorially difficult problems.

This paper presents a comparative analysis of the biomechanical characteristics of an external fixator with a frame made of two different materials (stainless steel and composite material) during anterior–posterior bending. Before the test itself, two representative configurations of the Sarafix fixator were selected for application on the lower leg and upper extremities under the designations B50 and C50, which are most widely used in orthopedic practice. The examination of the biomechanical characteristics of the external fixator was carried out using the structural analysis of the construction performance of the Sarafix fixator using the finite element method, the results of which were verified through experimental tests. The developed experimental and FEM models study the movement of the fracture crack and enable the determination of the stiffness of structural designs as well as the control of the generated stresses at the characteristic locations of the fixator. The results show that the fixator with a carbon frame has lower stresses at critical points in the construction compared to the fixator with a steel frame, in the amount of up to 49% (at the measuring point MT+) or up to 46% (at the measuring point MT−) for both fixture test configurations. The fixator with a carbon frame has greater displacements at the fracture site compared to the fixator with a steel frame, in the amount of up to 45% (for configuration B50) or up to 31% (for configuration C50). The stiffness of the structure for both test configurations of the fixator is lower in the fixator with a carbon frame compared to the fixator with a steel frame by up to 27%. Based on the findings of this study, we can conclude that a fixator with a steel frame has better biomechanical characteristics compared to a carbon frame. [ABSTRACT FROM AUTHOR]

Functional oligopeptides derived from natural proteins are often used as targeting groups or therapeutic drugs but always suffer from a dramatic bioaffinity decrease due to the loss of conformational restriction in proteins, which increases their entropy state. It is worth noting that the linear Cys-Arg-Gly-Asp-Ser (CRGDS) oligopeptide can spontaneously restore its natural conformation by anchoring one terminus and forming hydrogen bonds on another terminus, on protein-like zwitterionic fifth-generation polyamide-amine (G5 PAMAM) nanocarriers, thus exhibiting high bioaffinity. However, the different physicochemical properties of nanocarriers have an impact on the bioaffinity recovery of linear CRGDS. In this work, it is found that the bioaffinity decreases with the reduction of generation of PAMAM and zwitterionic G3 PAMAM is a turning point for bioaffinity recovery via a series of in vitro experiments. This indicates that the spontaneous restoration of the native conformation of the RGD segment requires proper surface group density and structural rigidity of the zwitterionic nanocarrier for reducing the entropic energy of CRGDS peptides before binding. This approach paves a way for functional reproduction of protein molecules using low-cost synthetic polymers for extensive biomedical applications. [ABSTRACT FROM AUTHOR]

This paper numerically investigates the optimization of the geometric parameters and the coolant's inflow states of the perforated micropin-fins (MPFs) heat sink using an elitist nondominated sorting genetic algorithm-II (NSGA-II) coupled with a finite volume-based computational fluid dynamics (CFD) solver. Square-shaped MPFs with two circular perforations were considered for the investigations on the fluid flow and conjugate heat transfer using numerical simulations. Five design variables (two perforation diameters, their respective locations, and the inflow velocity) with the essential constrained equations were optimized to search for the optimal solutions. Two objective functions, viz., Nusselt number (Nu) and friction factor (f), were selected to evaluate the hydrothermal performances of the perforated MPFs heat sink. The optimization was performed for 52 generations with a population size of 30. We obtained the Pareto optimal solutions, which gave the design boundary of the important parameters. Some of the cases of the Pareto solutions were also investigated in detail to understand the underlying thermal physics and structural rigidity under thermal and hydraulic stresses. It is observed that the MPF's stiffness was not compromised upon introducing two perforations. This study identified different thermohydraulic features responsible for optimal performance at different inflow velocity regimes. The present paper demonstrates that this optimization technique has led to a better understanding of the underlying thermal physics of complex electronic cooling equipment while systematically exploring the design space. [ABSTRACT FROM AUTHOR]

The design of road surfaces involves application of a sophisticated algorithm system based on mathematical calculations and engineering solutions, with the calculation of evaluation criteria. It is precisely the observance of the standardized requirements in terms of design criteria that makes it possible to consider the design of the pavement as reliable, and the road as safe and convenient for traffic during the specified service life. When calculating the strength, based on the predicted traffic intensity and the composition of the traffic flow, calculations are carried out according to the main criteria: admissible elastic deflection, shear in layers of non-reinforced materials and in asphalt concrete, as well as the ultimate tensile stresses in cast-in-situ materials with the specified reliability level. However, in the accepted concepts for calculating the strength and reliability of road pavements, only the force effect is directly taken into account. To take into account environmental factors, it is necessary to develop a comprehensive indicator of the resulting impact of all factors. The paper presents a complex of factors influencing on traffic safety, road deformations and irregularities the height of unevenness, in particular, an increase in the dynamic impact on the road and the amplitude of vibration of a car wheel on a road with an uneven surface (when detached from the road surface), the coincidence of the vibration frequency of the car with the natural frequencies of vibration of the road surface, and as a consequence, on the behavioral features of driving. The arguments have been substantiated that the predictive models do not take into account a number of factors that have a significant impact on the formation of irreversible deformation in the layers of materials of road structures.

This paper presents a comparative analysis of the biomechanical characteristics of an external fixator with a frame made of two different materials (stainless steel and composite material) during anterior–posterior bending. Before the test itself, two representative configurations of the Sarafix fixator were selected for application on the lower leg and upper extremities under the designations B50 and C50, which are most widely used in orthopedic practice. The examination of the biomechanical characteristics of the external fixator was carried out using the structural analysis of the construction performance of the Sarafix fixator using the finite element method, the results of which were verified through experimental tests. The developed experimental and FEM models study the movement of the fracture crack and enable the determination of the stiffness of structural designs as well as the control of the generated stresses at the characteristic locations of the fixator. The results show that the fixator with a carbon frame has lower stresses at critical points in the construction compared to the fixator with a steel frame, in the amount of up to 49% (at the measuring point MT+) or up to 46% (at the measuring point MT−) for both fixture test configurations. The fixator with a carbon frame has greater displacements at the fracture site compared to the fixator with a steel frame, in the amount of up to 45% (for configuration B50) or up to 31% (for configuration C50). The stiffness of the structure for both test configurations of the fixator is lower in the fixator with a carbon frame compared to the fixator with a steel frame by up to 27%. Based on the findings of this study, we can conclude that a fixator with a steel frame has better biomechanical characteristics compared to a carbon frame.

The minimization of thermal quenching, which leads to luminescence loss at high temperatures, is one of the most important issues for near‐infrared phosphors. In the present work, we investigated the properties of near‐infrared Ca(Sc,Mg)(Al, Si)O6 : Cr3+ phosphors with a pyroxene‐type structure under blue light excitation. The CaScAlSiO6 : Cr3+ end member of Ca(Sc,Mg)(Al,Si)O6 : Cr3+ phosphor led to broadband emission at a full‐width half maximum of 215 nm, whereas the CaMgSi2O6 : Cr3+ end member exhibited high thermal stability at 150 °C, with an intensity of 88.4 % of that at room temperature. The structural analysis and density functional theory calculations revealed the absence of soft conformations and local space confinement contributed to the high structural rigidity and weakened the thermal quenching effect. [ABSTRACT FROM AUTHOR]

The elegant geometry of viruses has inspired bio‐engineers to synthetically explore the self‐assembly of polyhedral capsids employed to protect new cargo or change an enzymatic microenvironment. Recently, Yang and co‐workers used DNA nanotechnology to revisit the icosahedral capsid structure of the phiX174 bacteriophage and reloaded the original viral genome as cargo into their fully synthetic architecture. Surprisingly, when using a favorable combination of structural rigidity and dynamic multivalent cargo entrapment, the synthetic particles were able to infect non‐competent bacterial cells and produce the original phiX174 bacteriophage. This work presents an exciting new direction of DNA nanotech for bio‐engineering applications which involve bacterial interactions. [ABSTRACT FROM AUTHOR]

Combined in silico, in vitro, and in vivo comparative studies between isogenic-recombinant Mouse-Hepatitis-Virus-RSA59 and its proline deletion mutant, revealed a remarkable contribution of centrally located two consecutive prolines (PP) from Spike protein fusion peptide (FP) in enhancing virus fusogenic and hepato-neuropathogenic potential. To deepen our understanding of the underlying factors, we extend our studies to a non-fusogenic parental virus strain RSMHV2 (P) with a single proline in the FP and its proline inserted mutant, RSMHV2 (PP). Comparative in vitro and in vivo studies between virus strains RSA59(PP), RSMHV2 (P), and RSMHV2 (PP) in the FP demonstrate that the insertion of one proline significantly resulted in enhancing the virus fusogenicity, spread, and consecutive neuropathogenesis. Computational studies suggest that the central PP in Spike FP induces a locally ordered, compact, and rigid structure of the Spike protein in RSMHV2 (PP) compared to RSMHV2 (P), but globally the Spike S2-domain is akin to the parental strain RSA59(PP), the latter being the most flexible showing two potential wells in the energy landscape as observed from the molecular dynamics studies. The critical location of two central prolines of the FP is essential for fusogenicity and pathogenesis making it a potential site for designing antiviral. [ABSTRACT FROM AUTHOR]

This research paper outlines the methodology and application of geometric and static accuracy assessment of articulated industrial robots using the Extended Double Ball Bar (EDBB) as well as the Loaded Double Ball Bar (LDBB). In a first experiment, the EDBB is used to assess the geometric accuracy of a Comau NJ-130 robot. Advanced measuring trajectories are investigated that regard poses or axes configurations, which maximize the error influences of individual robot components, and, in this manner, increase the sensitivity for a large number of individual error parameters. The developed error-sensitive trajectories are validated in experimental studies and compared to the circular trajectories according to ISO 203-4. Next, the LDBB is used to assess an ABB IRB6700 manipulator under quasi-static loads of up to 600 Newton using circular testing according to ISO 230-4. The stiffness is identified from the loaded circular trajectories. Then, the stiffness is used to perform a reverse calculation to identify the kinematic errors on the path deviations. The concept is validated in a case study of quasistatic loaded circular testing using the LDBB compared to a Leica AT960 laser tracker (LT). [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) light allows fast and nondestructive detection with deep penetration into biological tissues and is widely used in food inspection, biomedical imaging, night vision security, and other fields. Cr 3+ -doped NIR first region (NIR-I) phosphors have many interesting features that have attracted a lot of attention recently. However, practical issues, such as low photoluminescence quantum efficiency and poor thermal stability, need to be addressed. We synthesized Cr 3+ -doped Lu 2 SrAl 4 SiO 12 garnet-type phosphors using a high-temperature solid-state reaction method. Under blue-light (@ 430 nm) excitation, the phosphors exhibited broadband NIR-I emission in the range of 600-1000 nm, with an emission peak at 710 nm. This system is unique, as the emission had multipeak sharp-line superposition and the Cr 3+ ions were situated in a relatively strong crystal field environment, as opposed to a weak crystal field environment for other matrix. The optimal doping content of Cr 3+ ions was 2 mol %, and its internal quantum efficiency was ∼76.8%. Surprisingly, this NIR phosphor showed an antithermal quenching effect, and the integrated luminescence intensity of NIR-I emission measured at 573 K was 206.3% of that measured at 303 K. We found that the antithermal quenching of NIR-I luminescence was caused by the extremely low thermal expansion coefficient and rigid structure of the Lu 2 SrAl 4 SiO 12 matrix in the temperature range, as well as the weakening of electron-phonon coupling with increasing temperature. The optimized phosphor was packaged with a blue chip into a NIR phosphor-converted light-emitting diode device. The light source device showed an output power of 119.02 mW and an electro-optical conversion efficiency of 11.02% under a driving current of 300 mA. The application potential of this NIR phosphor was demonstrated in the field of high-resolution nondestructive imaging.

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) as a new NIR light source has outstanding application potential in the fields of NIR spectroscopy analysis, sensing, imaging, and pattern recognition. Therefore, the development of NIR phosphors with good NIR luminescence thermal stability has attracted much attention. To this end, we developed LiAlO 2 :Cr 3+ garnet-type NIR phosphors by a high-temperature solid-state reaction method. Under 405 nm excitation, the Cr 3+ ions located in tetrahedrons of LiAlO 2 emit NIR emission in a broadband NIR emission that covers 650-900 nm mixed with several sharp narrowband R-line emissions, which showed excellent luminescence thermal stability with integrated intensity of emission measured at 573 K is ∼90.86% of that measured at 303 K caused by good structural rigidity and low thermal expansion coefficient of the matrix material. An NIR pc-LED device assembled with the optimized LiAlO 2 :Cr 3+ and a commercially available purple LED chip emitted NIR output power of ∼98.172 mW at a driving current of 300 mA and demonstrated an electro-optical conversion efficiency of ∼9.09%, while demonstrated it has excellent application potential in the fields of night vision monitoring and biomedical imaging.

Propose: Investigation of mathematical solutions for including the self-weight of a column for calculating buckling critical load. The complexity of including self-weight resides in the fact that the mathematical formulation depends on elliptical integral solutions related to differential equations of the problem. Method: Comparing the analytical solutions with computation modeling. The obtained results with these computational models are approximate since they depend on the discretization of the domain of the problem while analytical solutions tend to be exact. An experimental activity was carried out for analyzing mathematical accuracy. Results: The investigation of buckling was performed through static as well as dynamic analysis. The results found shown differences smaller than 5% among the mathematical investigated solution. Besides that, all solutions represented well the problem in comparison with a laboratory test. Conclusion: It has been evaluated solutions for stability analyses of bars under self-weight, using Euler–Greenhill analytical approach, solutions with the eigenvalues from FEM analysis, and also a dynamic solution based on the Rayleigh's method, comparing them with dynamic laboratory tests. Can be concluded that the mathematical ways and the experimental investigation had a good agreement. Level of evidence: IV, evidence obtained from multiple mathematical methods, static and dynamic, is experimentally confirmed. [ABSTRACT FROM AUTHOR]

Purpose: To quantitatively evaluate the combined influence of implant diameter and alveolar ridge width on crestal bone stress. Materials and Methods: ITI solid-screw implants, 10 mm in length and 3.3, 4.1, and 4.8 mm in diameter, and the alveolar bone were modeled using axisymmetric finite elements. Four different alveolar ridge geometries were selected for each implant: 5-, 6-, 7-, and 8-mmwide ridges for the 3.3-mm implants; 6-, 7-, 8-, and 9-mm-wide ridges for the 4.1-mm implants; and 7-, 8-, 9-, and 10-mm-wide ridges for the 4.8-mm implants. A nonaxial oblique load of 100 N was applied at 30 degrees to the implant axis. Regression analysis was used to avoid ambiguity when estimating the peak stress occurring at the coronal contact point between the implant and the crestal bone, ie, the singularity point. Results: Peak stresses were dependent on both implant diameter and alveolar ridge width. Substantially lower stresses were recorded around the implants placed in narrower ridges. Conclusion: A regression analysis may be used to quantify the peak stress at the singularity point. An implant with a diameter that is at least half the ridge width is recommended to reduce the stress concentration in the crestal bone. [ABSTRACT FROM AUTHOR]

The entry of the SARS-CoV-2, a causative agent of COVID-19, into human host cells is mediated by the SARS-CoV-2 spike (S) glycoprotein, which critically depends on the formation of complexes involving the spike protein receptor-binding domain (RBD) and the human cellular membrane receptor angiotensin-converting enzyme 2 (hACE2). Using classical site density functional theory (SDFT) and structural bioinformatics methods, we investigate binding and conformational properties of these complexes and study the overlooked role of water-mediated interactions. Analysis of the three-dimensional reference interaction site model (3DRISM) of SDFT indicates that water mediated interactions in the form of additional water bridges strongly increases the binding between SARS-CoV-2 spike protein and hACE2 compared to SARS-CoV-1-hACE2 complex. By analyzing structures of SARS-CoV-2 and SARS-CoV-1, we find that the homotrimer SARS-CoV-2 S receptor-binding domain (RBD) has expanded in size, indicating large conformational change relative to SARS-CoV-1 S protein. Protomer with the up-conformational form of RBD, which binds with hACE2, exhibits stronger intermolecular interactions at the RBD-ACE2 interface, with differential distributions and the inclusion of specific H-bonds in the CoV-2 complex. Further interface analysis has shown that interfacial water promotes and stabilizes the formation of CoV-2/hACE2 complex. This interaction causes a significant structural rigidification of the spike protein, favoring proteolytic processing of the S protein for the fusion of the viral and cellular membrane. Moreover, conformational dynamics simulations of RBD motions in SARS-CoV-2 and SARS-CoV-1 point to the role in modification of the RBD dynamics and their impact on infectivity.

The authors have developed and investigated experimentally physical and mathematical models to calculate pressure pulsations and dynamic loads produced by them, which determine vibration transfer through compensators of pipelines with a liquid. The loads caused by pressure pulsations may substantially increase with frequency. Consideration has been given to vibration transfer over the structure of the compensator′s elastic elements. The authors have shown analytically and have confirmed experimentally the presence of a broad frequency range, in which the compensation of the forces transferred over the structure by the forces from pressure pulsations occurs. Vibration transfer may be reduced ten or more times compared to the transfer over the structure of the compensator with a liquid. The revealed phenomenon has been explained physically, and the ways of using it in practice have been proposed. At frequencies exceeding this range, the presence of the liquid enhances vibration transfer through the compensator. [ABSTRACT FROM AUTHOR]

Compared to other extrinsic phonon scattering mechanisms such as surface and interior defects, phonon scattering and lattice thermal resistance due to structural rippling in few-layer two-dimensional (2D) materials are under-examined. Here, the temperature-dependent basal-plane thermal conductivities (κ) of one rippled and four flat molybdenum disulfide (MoS2) samples are measured using a four-probe thermal transport measurement method. A flat 18 nm thick sample and a rippled 20 nm thick sample show similar peak κ values of 122 ± 17 and 129 ± 19 W m−1 K−1, respectively. In comparison, a 32 nm thick flat sample has a peak κ value of only 58 ± 11 W m−1 K−1 despite having an increased thickness. The peak thermal conductivities of the five samples decrease with increasing integrated Raman intensity caused by defects in the frequency range of the phonon bandgap in MoS2. In conjunction with the experimental findings, theoretical calculations of the temperature-, thickness-, strain-, and defect-dependent κ of thin MoS2 layers reveal the importance of interior defect scattering over scattering from compression-induced ripples and surface defects in these samples. The results further clarify the conditions where ripples are important in determining the basal plane thermal resistance in layered systems. [ABSTRACT FROM AUTHOR]

A metal free topological approach is demonstrated to mimic the photophysical properties of natural gfp by synthesizing two gfp chromophore integrated conjugated microporous polymers (o-HBDI-TEB-CMP and o-MBDI-TEB-CMP). Interestingly, owing to the structural rigidity, the emission (λem = 515 nm) and excited state lifetime (4.1 ns) of hydroxy substituted o-HBDI-TEB-CMP are found to be similar to the natural gfp. The crucial role of the –OH group for the green emission is further supported by –OMe substituted o-MBDI-TEB-CMP (λem = 440 nm) and also validated theoretically. [ABSTRACT FROM AUTHOR]

The versatile basic structure of piperazine allows for the development and production of newer bioactive molecules that can be used to treat a wide range of diseases. Piperazine derivatives are unique and can easily be modified for the desired pharmacological activity. The two opposing nitrogen atoms in a six-membered piperazine ring offer a large polar surface area, relative structural rigidity, and more acceptors and donors of hydrogen bonds. These properties frequently result in greater water solubility, oral bioavailability, and ADME characteristics, as well as improved target affinity and specificity. Various synthetic protocols have been reported for piperazine and its derivatives. In this review, we focused on recently published synthetic protocols for the synthesis of the piperazine and its derivatives. The structure-activity relationship concerning different biological activities of various piperazine-containing drugs was also highlighted to provide a good understanding to researchers for future research on piperazines., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The competition between the structural rigidity and the van der Waals interactions may lead to collapsing of aligned nanotubes, and the resulting changes of both configurations and properties promise the applications of nanotubes in nano-composites and nano-electronics. In this paper, a finite-deformation model is applied to study the adhesion of parallel multiwall nanotubes with both partial and full collapsing, in which the noncontact adhesion energy is analytically determined. The analytical solutions of both configurations and energies of collapsed nanotubes are consistent with the molecular dynamics (MD) results, demonstrating the effectiveness of the finite-deformation model. To study the critical conditions of generating the partially and fully collapsed multiwall nanotubes, our analytical model gives the predictions for both the geometry- and energy-related critical diameters, which are helpful for the stability analysis and design of nanotube-based nano-devices. [ABSTRACT FROM AUTHOR]

Highlights • State of the art on the typology and retrofitting methods of masonry structures. • New post-earthquake repair method for damaged brick masonry infills of steel frame. • Urgent disaster management strategy by efficient in-situ repair method. • Recovering a damaged infill specimen in term of strength, stiffness, and ductility. • Applicable design methodology of the present repair method is recommended. Abstract The present paper first reviews the scientific information about masonry buildings in terms of the structural performance of different masonry walls, usual pre-earthquake retrofitting methods, and post-earthquake repair methods. From this, it is found that limited information is available on applicable repair methods for damaged masonry walls after the occurrence of an earthquake event. There is an essential need from the perspective of disaster management strategies to provide urgent aid to casualties of moderate seismic events well before preparing damage assessment data and a comprehensive retrofitting program for the earthquake-affected area. For this reason, three experiments were designed to investigate the effect of brick masonry infill on a simple steel frame and the success rate of a new method of repairing damaged infill. In the proposed repair method, cracks in the damaged masonry infill are stitched by crimped wire meshes in the shape of Band-Aids and cementitious plaster is used to coat the attached wire meshes. The crimped wire meshes must be fastened to the infill with hooked driven nails and must be attached perpendicular to diagonal crack paths and the four corners and centre of the infill. This method is presented for efficient and simple in situ repair interventions to provide temporary residency for casualties. Usage of plasters including accelerated cement or application of accelerated curing methods can reduce the time of repair construction and prepare the proposed method for urgent aids against aftershocks. No inappropriate structural effects of the steel frame-infill interaction were observed during these tests. Furthermore, the results indicated that the repair method not only restored the lost strength of the damaged infill but also recovered the stiffness and ductility of the reference specimen based on the experimental evidence. Following the experiments, a practical design methodology for the required crimped wire mesh specification based on the length of the infill diagonal cracks was recommended. [ABSTRACT FROM AUTHOR]

Highlights • Lateral rigidity of corrugated plate sidewalls in container-like modules was derived. • Rigidity of modules with strong ceiling, weak ceiling and without sidewalls were simulated. • Corrugated plate sidewalls presented considerate strengthening effect on lateral rigidity. • Ignorance of corrugated steel plate stiffness may underestimate structural lateral resistance and induce risk. • Structural optimization suggestions of inter-corridor modular apartment was provided. Abstract Modular construction comprises of prefabricated, room-sized volumetric units that are normally fully fitted out in factory and installed on-site, thus possessing high constructional efficiency and receiving considerable attention in recent years. However, given the limited design guidance on modular structures, the strengthening effect of sidewalls or wall panels is frequently ignored and is often regarded as a safety stock in practical structural design. This study mainly focused on the stiffness strengthening effect of corrugated sidewalls in a container-like module. The rigidity calculation and a simplified model of a corrugated steel plate sidewall were presented. And then the rigidity contribution of corrugated plate sidewalls was incorporated into the structural design of a multi-story modular apartment. Results indicated that the corrugated plate sidewall in container-like modules can significantly increase the structural rigidity. The presence of modular corrugated plate sidewall can strengthen the lateral resistance and effectively improve the global rigidity of modular structures. The ignorance of corrugated plate stiffness may change the deformation and internal force distribution pattern and may also induce damage risk in modular buildings. [ABSTRACT FROM AUTHOR]

Comprising rigid bars and spring systems at the joints and in the cells, the Hencky bar-net model (HBM) has been shown to be a physical structural representation of the finite difference plate model (FDM). In this paper, the HBM is extended for the vibration analysis of rectangular plates with rectangular cutouts. This extension addresses the rotationally elastic and transverse spring stiffnesses for the HBM at the cutout corners. After verifying the HBM model by comparing the vibration results with existing solutions for some plate problems, the model is used to obtain some new free vibration solutions for plates having various boundary conditions including cracked corners modelled by free small rectangular cutouts. [ABSTRACT FROM AUTHOR]

Abstract We show that the non-compact generalised analytic Volterra operators T g , where g ∈ BMOA , have the following structural rigidity property on the Hardy spaces H p for 1 ≤ p < ∞ and p ≠ 2 : if T g is bounded below on an infinite-dimensional subspace M ⊂ H p , then M contains a subspace linearly isomorphic to ℓ p. This implies in particular that any Volterra operator T g : H p → H p is ℓ 2 -singular for p ≠ 2. [ABSTRACT FROM AUTHOR]

Abstract In order to study the nonlinear dynamic behaviors of Thermal Protection System (TPS) and the nonlinear dynamic strength of the strain-isolation-pad (SIP), a two degree-of-freedom nonlinear dynamic theoretical model was presented under the acoustic excitation and base excitation. The tile is simplified as a mass point, a linear spring and a damping element, and the SIP is simplified as a mass point, a nonlinear spring and a damping element. On this basis, the solving process of the nonlinear theoretical model and the iterative process of the equivalent linear stiffness coefficient of SIP were derived by the statistical linearization method. The dynamic responses analyzed by the nonlinear theoretical model and linear theoretical model are compared. The nonlinear stiffness of SIP shows obvious influence on behaviors of TPS and dynamic stress of SIP, and the equivalent linear stiffness of SIP is related to the types of excitations. Finally, the influences on above dynamic responses by the nonlinear stiffness level of SIP were studied. The equivalent linear stiffness coefficient of SIP, acceleration of TPS and dynamic stress of SIP decrease with the increase of the nonlinear level for the stiffness of SIP. Highlights • Nonlinear dynamic theoretical model is presented for TPS. • Nonlinear stiffness of SIP is considered. • Iterative process of equivalent linear stiffness coefficient of SIP is derived. • Effects on dynamic responses by nonlinear stiffness level of SIP are studied. [ABSTRACT FROM AUTHOR]

A method for calculating isolation ratios of mounts at a powertrain mounting systems (PMS) is proposed assuming a powertrain as a rigid body and using the identified powertrain excitation forces and the measured IPI (input point inertance) of mounting points at the body side. With measured accelerations of mounts at powertrain and body sides of one Vehicle (Vehicle A), the excitation forces of a powertrain are identified using conversational method firstly. Another Vehicle (Vehicle B) has the same powertrain as that of Vehicle A, but with different body and mount configuration. The accelerations of mounts at powertrain side of a PMS on Vehicle B are calculated using the powertrain excitation forces identified from Vehicle A. The identified forces of the powertrain are validated by comparing the calculated and the measured accelerations of mounts at the powertrain side of the powertrain on Vehicle B. A method for calculating acceleration of mounting point at body side for Vehicle B is presented using the identified powertrain excitation forces and the measured IPI at a connecting point between car body and mount. Using the calculated accelerations of mounts at powertrain side and body side at different directions, the isolation ratios of a mount are then estimated. The isolation ratios are validated using the experiment, which verified the proposed methods for estimating isolation ratios of mounts. The developed method is beneficial for optimizing mount stiffness to meet mount isolation requirements before prototype. [ABSTRACT FROM AUTHOR]

Nitrogen doped carbon quantum dot based highly selective luminescent probe has been designed for the detection of herbicide atrazine. Nitrogen doped carbon quantum dot with PLQY 28% has been prepared from hydrothermal treatment of orthophenylene diamine. The turn-on fluorescence of the probe on addition of atrazine is attributed to aggregation induced fluorescence enhancement of amine functionalized carbon dot. The hydrogen bonding interaction of surface amine groups of carbon dot probe and atrazine makes the probe selective and ultrasensitive towards atrazine even in presence of other pesticides and metal ions. The limit of detection for atrazine sensing was found to be 3 pM, which is the lowest among all reported methods for the detection of atrazine. Due to low detection limit the utility of the developed sensor has also been explored in real agricultural samples. Owing to the excellent luminescence property and photostability this fluorescent probe can also be utilised to detect atrazine in bacterial cell by imaging. [ABSTRACT FROM AUTHOR]

Abstract: Two previous studies suggested that part of the cation sorption sites in soil organic matter with low exchange capacity have to be considered as “lonely”, i.e., too far from each other to allow direct cross‐linking by bivalent cations. The objective of this contribution was to understand the mechanisms controlling structural rigidity and physicochemical aging of the SOM (soil organic matter) and the role of water molecule bridges (WaMB) therein. For this, we evaluated the matrix rigidity of an organic surface layer of a Haplic Podzol on a quantitative basis, by assessing WaMB transition temperature (T*) directly after treatment with bivalent cations (Mg2+, Ca2+, or Ba2+) and after eight weeks of aging. Cation loading as well as cation type influenced matrix rigidity. Ba2+ induced the most rigid matrix and Mg2+ the weakest, which is in line with their binding strength in terms of Langmuir coefficient. The matrix rigidity increased with the cross‐linking activity, which is the product of loading and Langmuir constant of the respective cation. The aging process, however, was slowed down by the initial matrix rigidity, and the rigidity of the aged matrix decreased with increasing Langmuir constant. The degree of aging increased with increasing hydration enthalpy of the cation and decreased with increasing cation loading. Thus, directly after cation treatment, direct cross‐links by multivalent cations were most relevant, but WaMB increasingly gained influence on the matrix rigidity during aging. The untreated sample revealed a considerable number of WaMB, resulting in a fairly rigid and strongly cross‐linked matrix which, however, flexibly reacts on external influences like change in cation concentration or relative humidity. With these findings, the ideas on the relevance of indirect CaB‐WaMB associations between distant sorption sites for the rigidity and flexibility of the OM matrix as proposed in previous studies were confirmed on a mechanistic basis in this study. [ABSTRACT FROM AUTHOR]

Recently, weight reduction and improvement of crashworthiness of auto bodies have become important issues. At the same time, stiffness of auto bodies is also needed to ensure a smooth ride. Using hollow parts, such as bended pipes and hydroformed parts, is one of the solutions to the demand for both rigidity and light weight. To weld hollow parts and sheet panels together, welding methods which allow us to access from one side are required. Single-side resistance spot welding (single-side RSW) process is one of those, and has recently been attracting attention. However, because of the long current path and small electrode force, it is difficult to concentrate the electric current in the welding spot compared with conventional direct resistance spot welding (direct RSW). Furthermore, in multipoint welding, shunt current will occur easily, and the nugget formation will be inhibited. To obtain a guideline for making sound nuggets, influencing factors for shunt current were investigated. In addition, a numerical study was carried out to discuss the difference between direct RSW and single-side RSW. According to the CAE analysis, the shunt current of single-side RSW will be higher rate than direct RSW. The rate of shunt current was influenced by the electrical resistance of its current path. For this reason, with shorter distance between welding points, or with lower electrical resistance of material, it is difficult to get large nuggets. By enhancing the electrical resistance of shunt current path, shunt current could be reduced and a larger nugget would be obtained. [ABSTRACT FROM AUTHOR]

Reinforced concrete (RC) T-shaped walls have been studied by many researchers over the past decades due to their popularity. Among them, however, few investigations are conducted regarding T-shaped squat walls, especially for their seismic behaviors under nonprincipal bending action. To build the database and improve the understanding of structural walls, reversed cyclic tests of four RC T-shaped squat walls were conducted under displacement control. The variables were axial loads and lateral loading directions. Seismic responses of specimens were presented and assessed in detail from various aspects. Nonlinear section analyses and finite element modeling were also performed to facilitate investigations. The results indicated a significant shear lag effect exited in some T-shaped squat walls, which distinctly affected the strength and stiffness of test specimens. It was also found the impact of the shear lag effect increased with additional axial loads, and decreased as the test progressed. [ABSTRACT FROM AUTHOR]

The use of elastic analysis is prevalent in the design of building structures even under loading conditions where inelasticity would be expected. Accordingly, geometric and material properties used in the elastic analyses must be carefully selected to maintain accuracy. Steel-concrete composite columns experience different forms of inelasticity. Concrete cracking is the source of much of the inelasticity and occurs at relatively low levels of load, but partial yielding of the steel, slip between concrete and steel, and concrete crushing also contribute to losses in stiffness. In this paper, the behavior of composite columns is characterized at the cross section and member levels through comparisons between inelastic and elastic analyses. Then, through a broad parametric study, specific practical design recommendations are developed for the elastic flexural rigidity of composite columns for the determination of lateral drifts under service loads. The recommendations in this paper provide simple and robust values for the stiffness of composite columns to be used for drift computations involving lateral loads. [ABSTRACT FROM AUTHOR]

In this paper we describe the first and second cohomology groups of a solvable Lie algebra. In particular, it is shown that the data of the group are trivial, which implies the rigidity of this Lie algebra. [ABSTRACT FROM AUTHOR]

In this study, the free vibration characteristics of variable stiffness laminated composite shells is numerically studied using a higher-order accurate theory. The unique feature of the variable stiffness composites is that the fiber orientation within the lamina changes continuously leading to spatial variation of stiffness of the resulting laminate. A systematic parametric study is conducted to bring out the influence of fiber orientation within and across the laminae, shell geometry and the structural theory on the fundamental frequency. The influence of environmental factors such as the temperature and the presence of moisture is also considered. It is inferred that the spatial variation of stiffness due to curvilinear fibres introduces additional flexibility in designing structures made of such materials. [ABSTRACT FROM AUTHOR]