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A Galerkin-based nonlinear normal mode approach based on the concept of invariant manifolds is adopted to analyze the effect of thermoelastic damping on the nonlinear vibrations of a microbeam with mid-plane stretching and electrostatic actuation. The derivation of the mathematical model starts with two coupled equations: a general Euler–Bernoulli equation for microbeam vibrations, which includes thermal moment and thermal force terms due to the thermoelastic damping effect; and a thermal equation describing the generation of the thermal moment due to bending vibrations. Given the available information about the material properties and geometry of conventional microbeams, and a physical reasoning based on it about the time constant of the thermal equation, the two governing equations are integrated into a single nonlinear partial differential equation. Galerkin discretization is used to transform the governing equation into a system of coupled nonlinear ordinary differential equations that are uncoupled at linear order. The modal analysis is then followed by finding an invariant manifold leading to a nonlinear ordinary differential equation that governs the vibration behavior of the system. The results of the case study showed that the amount of thermoelastic damping is dependent on the excitation voltage, and the damping increases with increasing voltage. Furthermore, in the presence of thermoelastic damping, by applying the step voltage and starting the vibrations, the frequency increases over time until it reaches a certain limit. With a higher excitation voltage, the frequency increases at a higher rate, but to a lower final limit. In an undamped system, the frequency of oscillations is constant over time, but a higher excitation voltage causes lower frequency vibrations. The results of pull-in analysis showed that thermoelastic damping has no significant effect on static or dynamic pull-in voltage. [ABSTRACT FROM AUTHOR]

Simple Summary: The nematode Caenorhabditis elegans, which is only 1 mm long, is used as a model to study the effects of irradiation on tissues (organs) of living organisms. This paper reviews the development of irradiation techniques using charged-particle microbeams in Japan, the U.S., China, and France, in which heavy-ion and proton beams (types of ionizing radiation) are targeted to specific cells or regions of C. elegans, and outlines the progress made over the past 20 years and where we are today. An essential part of irradiating the targeted cell/tissue of microscopic animals is having an immobilization method which does not damage the animals' physiological activity. This article introduces some technical difficulties that differ from those concerning the irradiation of cultured cells, which have been the main target of irradiation in the past. Charged-particle microbeam irradiation devices, which can convert heavy-ion or proton beams into microbeams and irradiate individual animal cells and tissues, have been developed and used for bioirradiation in Japan, the United States, China, and France. Microbeam irradiation technology has been used to analyze the effects of irradiation on mammalian cancer cells, especially bystander effects. In 2006, individual-level microbeam irradiation of the nematode Caenorhabditis elegans was first realized using JAEA-Takasaki's (now QST-TIAQS's) TIARA collimated microbeam irradiation device. As of 2023, microbeam irradiation of C. elegans has been achieved at five sites worldwide (one in Japan, one in the United States, one in China, and two in France). This paper summarizes the global progress in the field of microbeam biology using C. elegans, while focusing on issues unique to microbeam irradiation of live C. elegans, such as the method of immobilizing C. elegans for microbeam experiments. [ABSTRACT FROM AUTHOR]

The microsensor is modeled as a two-layer micro beam in which the first layer is quartz and the second layer is silicon. This beam is clamped-free and beam has a rectangular cross-section. Sensitivity and quality factors which are two important functions in sensors are selected as objective functions. Dimensions of the micro beam are design variables, so this optimization has two functions and four variables of the design. Objective functions are depended on the natural frequency, material properties, and dimensions of the beam. The natural frequency is obtained according to the modified couple stress theory by using Rayleigh's method. Optimization is done by using genetic algorithm. Results show the length of the beam has a significant effect on the sensitivity and quality factor. Also, it can be seen that when dimensions of the beam decrease, sensitivity increases, and quality factor decreases. Results are presented based on non-classical and the classical theories. [ABSTRACT FROM AUTHOR]

• A model for the bending of the ssDNA-microbeam with surface charge effect is established. • The electric potential distribution is calculated by using finite difference method and Newton's iteration method. • The surface charge density can modulate the bending of the ssDNA-microbeam. A unified energy model for mechanical deformation of the microbeam included by single stranded DNA (ssDNA) adsorption considering the surface charge density on substrate is investigated. First, a free energy model is established to quantify the deflection and axial displacement of the microbeam, the ion concentration in the solution, as well as the electric potential distribution inside and outside the ssDNA film with a uniform surface charge density. Then, the governing equations and corresponding boundary conditions are obtained by minimizing the free energy with three types of variational variables. And, the relationship of the electric potential difference between the two sides of the ssDNA film and the deformation of microcantilever and simply support beam are determined in different solutions (1: 1, 1: 2, 1: 3). Moreover, the numerical solutions of the electric potential distribution inside and outside the ssDNA film are investigated by using the finite difference method and Newton's iteration method. The results suggest that the nonlinear model for electric potential distribution should be used under higher surface charge density. By fitting and comparing the present predictions with Arroyo-Hernandez's experimental data, the effectiveness of the model is verified. The study shows that the surface charge density can modulate the magnitude and direction of ssDNA-microbeam deformation, which also indicates that there exists a critical surface charge density, causing the failure of ssDNA-microbeam detection. These conclusions are helpful for designing the efficient biosensors based on DNA-microbeam. [ABSTRACT FROM AUTHOR]

Introduction: Spatially Fractionated Radiation Therapy (SFRT) is an unconventional therapeutic approach with the potential to disrupt the classical paradigms of conventional radiation therapy. The high spatial dose modulation in SFRT is believed to activate distinct radiobiological mechanisms which lead to remarkable increases in normal tissue tolerance. To make optimal use of SFRT and its benefits, a deeper understanding of the biological response and its relationship with the complex dosimetric and geometric components of SFRT is essential. Method: A retrospective evaluation of preclinical studies was conducted to gain insight into the dosimetric and geometric parameters that are most correlated with normal tissue response. Current literature evaluates the response of tissue to MBRT and MRT according to various end points, e.g. the level of desquamation, degree of necrosis, or the amount of malcalcification. A set of metrics was developed to allow a quantitative comparison of these results. Results: The strongest correlations were observed with the doses in both the peaks and valleys as well as the ratio of the area covered by the peak over the total area. This emphasises the geometry of the beam. MBRT challenged previous uniform dose-distribution paradigms by highlighting the critical role of Peak Dose alongside Valley Dose in tissue sparing whereas MRT underscores the significant influence of geometric beam parameters on tissue preservation. Discussion: The data exhibits variability in the results obtained using different animal models and endpoints and additional research is warranted to explore the trends observed in this study under controlled conditions. [ABSTRACT FROM AUTHOR]

Within the framework of the nonlocal strain gradient and the Euler–Bernoulli beam theories, a model of electrostatically actuated functionally graded (FG) microbeams is developed taking into account the intermolecular interaction forces in it. In addition to the electrostatic forces resulting from the applied DC voltage between a fixed substrate and the FG microbeam, the Casimir and van der Waals forces were also considered. The governing equation of motion of FG microbeams was derived by employing the Hamilton principle. Utilizing the Galerkin and the equivalent linearization methods, an analytical solution was obtained for the nonlinear vibration problem with zero initial conditions. To validate the accuracy of the results obtained, our solution was compared with the numerical and analytic solutions published in the literature. [ABSTRACT FROM AUTHOR]

The present study illustrates the thermoelastic vibrations of a rotating microbeam caused by a laser pulse heat source and sinusoidal heating in the context of three-phase thermoelasticity. Mathematical modeling of the problem was developed using the concept of the Euler–Bernoulli beam theory and the generalized theory of thermal conductivity with three relaxation coefficients of time. It was taken into account that the flexible beam suffers from initial stress at the beginning. The microbeam motion equation was derived by applying the assumptions of the Hamiltonian principle. The closed-form solutions of the studied domains are identified in the Laplace transform domain. After presenting the numerical inversion of the Laplace transform, the numerical results for the studied field variables, such as deflection and temperature, were developed. The influences of the angular velocity of rotation, the initially applied pressure, and the intensity of the laser pulse on the behavior of the physical fields have been demonstrated. In addition, the advantage of the current model has been verified by comparing the results of the field variables of the current model with the results of other thermal conduction theories, whether classical or generalized. It is believed that the results extracted from the present study may be useful for developing some high-quality electromechanical systems. [ABSTRACT FROM AUTHOR]

Highly compliant structures such as microbeams can deform substantially in response to interactions between molecules adsorbed on their surface. To understand such systems and improve their detection signals, a mechano-electro-chemical coupling model for mechanical deformations of the microbeams immobilized single-stranded DNA (ssDNA) is established due to flexoelectricity. The governing equations and corresponding boundary conditions of ssDNA microbeams are derived by using the variational principle. The bending deformations of ssDNA microbeams (one for cantilever beam and another for simply supported beam) are derived. The electric potential in the regions inside and outside the ssDNA layer is obtained by linear Poisson-Boltzmann equation for different electrolyte solutions. The analytical expressions to quantify the beam deflection and the potential difference of ssDNA layer are presented. The theoretical predictions are compared with the experimental data to validate the applicability of the present model. Numerical results reveal that the solution types, thickness, and elastic modulus of substrate materials have an obvious influence on the deflections of ssDNA microbeams. Therefore, the present model can help to improve the reading of the bending deformation signal of the microbeam biosensors. [ABSTRACT FROM AUTHOR]

The present investigation focuses on the design and mathematical modeling of a microelectromechanical (MEMS) mode-localized based sensor/actuator system. This device incorporates a sensitive clamped–clamped shallow arch microbeam with an initial curvature shaped to resemble one of the first two symmetric and asymmetric modes of free oscillations of a clamped–clamped beam. The analysis reveals that with a suitable arrangement of the initial shape of the device flexible electrode and a proper tuning of the maximum initial rise and the actuating dc load enables the transition to display certain bistable behavior. This could be a better choice to build a device with a large stroke. Furthermore, the generated data showed the occurrence of mode-veering, indicating a coupling between the concerned symmetric and asymmetric modes of vibrations, and offering the possibility for such a device to be used as a mode-localized MEMS-based sensor utilizing veering and crossing phenomena. Indeed, where a certain energy is exchanged between symmetric and asymmetric modes of a microbeam, it can be utilized to serve as a foundation for the development of a new class of highly precise resonant sensors that can capture, with a certain level of precision, any of the sensed signal amplitudes. [ABSTRACT FROM AUTHOR]

Charged-particle microbeam irradiation devices, which can convert heavy-ion or proton beams into microbeams and irradiate individual animal cells and tissues, have been developed and used for bioirradiation in Japan, the United States, China, and France. Microbeam irradiation technology has been used to analyze the effects of irradiation on mammalian cancer cells, especially bystander effects. In 2006, individual-level microbeam irradiation of the nematode Caenorhabditis elegans was first realized using JAEA-Takasaki’s (now QST-TIAQS’s) TIARA collimated microbeam irradiation device. As of 2023, microbeam irradiation of C. elegans has been achieved at five sites worldwide (one in Japan, one in the United States, one in China, and two in France). This paper summarizes the global progress in the field of microbeam biology using C. elegans, while focusing on issues unique to microbeam irradiation of live C. elegans, such as the method of immobilizing C. elegans for microbeam experiments.

The mechanical properties of native cellulose are critical for understanding the properties of natural biomaterials. To investigate the elastic moduli of the cellulose crystalline fraction an isotropic mechanical load using hydrostatic pressure ranging from 0.01 to 0.5 GPa was applied to flax fibers, pine wood and tension wood samples. The response of the crystalline part was monitored by using microfocused synchrotron radiation. The compressibility of the crystalline fraction of native cellulose was anisotropic and dependent on the crystal size and possibly on the composition of the sample. The compressibilities along the [001] direction, where covalent bonds hold the cellulose chains together, varied between 2.1 and 2.9 TPa−1 for the different samples and confirm similar values found for cotton fibres. However, the compressibilities along the [100]-direction range from 56.2 TPa−1 to 63.5 TPa−1, slightly exceeding the previously determined value of 50 TPa−1, which can possibly be attributed to differences between individual samples. [ABSTRACT FROM AUTHOR]

Purpose: The mechanical behaviors of general microbeams are presented, including the lateral forced vibration of a symmetric straight microbeam subjected to transverse excitation and the buckling and postbuckling of a symmetric curved composite microbeam subjected to axial and thermal loads. Methods: To achieve this, the nonlocal elasticity theory is taken into account and the small scale parameter is involved to modeling the symmetric straight microbeam. The nonlinear partial differential equation governing microbeam lateral motion is derived due to the axial elongation, and a set of linear ordinary differential equations are derived by the method of multiple scales. The lateral displacement is determined and the amplitude-frequency relation is presented and discussed. Subsequently, the in-plane instability of functionally graded carbon nanotube reinforced composite curved microbeams in thermal environment is examined. Results: It is showed that an increase in carbon nanotube volume fraction improves the critical buckling load of the composite microbeams. The temperature-induced tensile loading and displacement also have remarkable effects. Furthermore, geometrical parameters can be used to determine the buckling mode of the composite microbeam due to its significant effect on critical buckling loads. Conclusions: The solutions of critical geometrical parameters are determined and they are affected by the temperature change, carbon nanotube distribution and volume fraction, respectively. [ABSTRACT FROM AUTHOR]

Purpose: In this paper, the nonlinear vortex-induced vibration of electrostatically actuated microbeam is studied based on modified strain gradient theory. The effects of mid-plane stretching, electrostatic actuation, Casimir and intermolecular forces are considered. Methods: By applying the Hamilton's principle, the governing equations of motion are derived by considering the three non-local Euler–Bernoulli, Timoshenko, and hyperbolic beam theories (HBT). The nonlinear governing equations of motion are discretized using the Galerkin method, and then the solution of the equation is determined by the numerical method. The dynamic response of the system, Fast Fourier Transform (FFT) spectrum, pull-in voltage, and amplitude-fluid flow velocity curves for different values of the small size effect parameter, applied voltage, and fluid flow velocity are extracted. Results: The results reveal that non-local HBT theory and for appropriate values of the small size parameter provides more accurate results than classical beam theory and the other two theories. It is observed that the presence of electrostatic force, shifting the range of the lock-in zone, and causes a significant increase in the maximum amplitude of the microbeam. Also, the results show that by increasing the fluid flow velocity, the influence of inertia on pull-in values considerably increases. Conclusion: In predicting the dynamic behavior of microbeams, the non-local hyperbolic beam theory has a greater accuracy than other models. It is worth mentioning that the parametric study is performed under relatively small deformation condition. In future work, the influence of nonlinear behavior and large deformations will be further investigated. [ABSTRACT FROM AUTHOR]

This study investigates the nonlinear vibration motions of the Euler–Bernoulli microbeam on a nonlinear elastic foundation in a uniform magnetic field based on Modified Couple Stress Theory (MCST). The effect of size, foundation, and magnetic field on the nonlinear vibration motion of microbeam has been examined. The governing equations related to the nonlinear vibration motions of the microbeam are obtained by using Hamilton's Principle, and the Multiple Time Scale Method was used to obtain the solutions for the governing equations. The linear natural frequencies of microbeam are presented in the table according to nonlinear parameters and boundary conditions. The linear and nonlinear natural frequency ratio graphs are shown. The present study results are also compared with previous work for validation. It is observed that length scale parameters and magnetic force have a more significant effect on the natural frequency of microbeams. It is seen that when the linear elastic foundation coefficient, the Pasternak foundation and the magnetic force effects increase, the ratio of nonlinear and linear natural frequency decreases. [ABSTRACT FROM AUTHOR]

Simple Summary: Using a focused heavy-ion microbeam that produces a highly precise beam spot, we developed a technology to uniformly irradiate specific tissues of an organism with a defined dose, which cannot be achieved by conventional methods. We evaluated the performance of the developed paint irradiation technology by irradiating the CR-39 ion track detector, confirming that the technology makes it possible to uniformly paint the area at a specified dose. The targeted irradiation of the pharynx and gonads of living Caenorhabditis elegans, which demonstrated the organ shape distribution of the irradiated ion, indicated that this technology will elucidate biological mechanisms that are difficult to analyze with conventional collimated microbeam irradiation. The functions of organisms are performed by various tissues composed of different cell types. Localized irradiation with heavy-ion microbeams, which inactivate only a portion of the constituent cells without destroying the physical intercellular connections of the tissue, is a practical approach for elucidating tissue functions. However, conventional collimated microbeams are limited in the shape of the area that can be irradiated. Therefore, using a focused heavy-ion microbeam that generates a highly precise beam spot, we developed a technology to uniformly irradiate specific tissues of an organism with a defined dose, which conventional methods cannot achieve. The performance of the developed paint irradiation technology was evaluated. By irradiating the CR-39 ion track detector, we confirmed that the new method, in which each ion hit position is placed uniformly in the irradiated area, makes it possible to uniformly paint the area at a specified dose. The targeted irradiation of the pharynx and gonads of living Caenorhabditis elegans demonstrated that the irradiated ions were distributed in the same shape as the targeted tissue observed under a microscope. This technology will elucidate biological mechanisms that are difficult to analyze with conventional collimated microbeam irradiation. [ABSTRACT FROM AUTHOR]

Simple Summary: We used the charged-particle microbeam of the AIFIRA facility to investigate the effects of targeted irradiation of the progenitor gonad stem region on the organogenesis of worm gonad and vulva. A dedicated experimental approach was developed to enable the manipulation and targeted irradiation of the progenitor gonad stem region. This was achieved using three MeV protons during a definite developmental stage of the worms. The outcomes revealed distinct developmental modifications and specific gene inductions involved in cellular stress and cuticle injury responses. These findings were proven through an integration of methodologies, encompassing micro-irradiation under the reversible immobilization of worms, confocal imaging, cell sorting assays, and long-read sequencing analysis. We describe a methodology to manipulate Caenorhabditis elegans (C. elegans) and irradiate the stem progenitor gonad region using three MeV protons at a specific developmental stage (L1). The consequences of the targeted irradiation were first investigated by considering the organogenesis of the vulva and gonad, two well-defined and characterized developmental systems in C. elegans. In addition, we adapted high-throughput analysis protocols, using cell-sorting assays (COPAS) and whole transcriptome analysis, to the limited number of worms (>300) imposed by the selective irradiation approach. Here, the presented status report validated protocols to (i) deliver a controlled dose in specific regions of the worms; (ii) immobilize synchronized worm populations (>300); (iii) specifically target dedicated cells; (iv) study the radiation-induced developmental alterations and gene induction involved in cellular stress (heat shock protein) and cuticle injury responses that were found. [ABSTRACT FROM AUTHOR]

Micro- and Nano beam MEMS devices possess a broad range of applications owing to their capability to produce precise mechanical motion and sensing capabilities at a small scale. In the field of biomedicine, these devices have been employed in applications such as tissue engineering, lab-on-a-chip systems, and implantable devices. Medical devices, particularly those involved in drug delivery, are significantly impacted by the forces applied to them. Therefore, it is imperative to carefully evaluate the effects of axial force and optimize the device's design to ensure that it can endure the forces it will encounter during operation. Despite being relatively weak, the van der Waals force warrants careful consideration when working at the micro- and nanoscales. In this research, the nonlinear equation obtained by the Galerkin method for a doubly clamped nano/micro-beam under the effect of Van der Waals (vdW) force was solved. The Homotopy Perturbation Method (HPM) and the Akbari Ganji Method (AGM) are introduced to investigate the nonlinear problem in this paper analytically. To validate and investigate the accuracy of the AG and HP methods, the obtained results were compared to the Runge-Kutta approach. The obtained results for all data sets showed the high accuracy of the AG and HP methods. Also, this paper investigated the effect of axial force N on beam type N/MEMS deflection. The axial force N effect in both tensional (N > 0) and compressive (N

In situ U‐Pb geochronology and hafnium, oxygen and zirconium isotope measurements in zircons using laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) and ion microprobe techniques can provide essential isotopic data to constrain geological evolutionary histories. Developing reliable zircon reference materials is the cornerstone for in situ zircon chronology and isotopic studies. In this study, the homogeneity of U‐Pb ages and Hf‐O‐Zr isotope ratios in three Sri Lankan zircon megacrysts (SLZA, SLZB and SLZC) were investigated using multiple analytical methods. The obtained U, Th, Pb and Hf mass fractions of the SLZA zircon were 839 ± 56 μg g‐1 (1s), 151 ± 15 μg g‐1 (1s), 198 ± 28 μg g‐1 (1s) and 8635 ± 286 μg g‐1 (1s), respectively. The mass fractions of U, Th, Pb and Hf in the SLZB zircon were 1106 ± 106 μg g‐1 (1s), 331 ± 61 μg g‐1 (1s), 376 ± 57 μg g‐1 (1s) and 9673 ± 976 μg g‐1 (1s), respectively. The U, Th, Pb and Hf mass fractions determined in the SLZC zircon were 551 ± 35 μg g‐1 (1s), 111 ± 8 μg g‐1 (1s), 129 ± 18 μg g‐1 (1s) and 7881 ± 393 μg g‐1 (1s), respectively. The chemical abrasion isotope dilution thermal ionisation mass‐spectrometry (CA‐ID‐TIMS) method yielded a Th‐corrected weighted mean 206Pb/238U age of 556.94 ± 1.29 Ma (95% conf., n = 5) for the SLZA zircon, 552.90 ± 1.29 Ma (95% conf., n = 7) for the SLZB zircon and 560.83 ± 1.29 Ma (95% conf., n = 7) for the SLZC zircon. The obtained Hf isotopic compositions of the SLZA, SLZB and SLZC zircons determined with the solution MC‐ICP‐MS method were 0.281651 ± 0.000014 (2s, n = 10), 0.281704 ± 0.000008 (2s, n = 10) and 0.281676 ± 0.000006 (2s, n = 10), respectively. The obtained O isotopes of the SLZA and SLZB zircons measured with the laser fluorination method were 12.14 ± 0.56‰ (2s, n = 4) and 11.91 ± 0.30‰ (2s, n = 4), respectively. The Zr isotopes of the SLZA, SLZB and SLZC zircons determined with double spike TIMS analysis yielded mean δ94/90ZrSRM3169 values of ‐0.03 ± 0.06‰ (2s, n = 10), ‐0.03 ± 0.04‰ (2s, n = 10) and 0.00 ± 0.07‰ (2s, n = 8), respectively. The SLZA zircon can be used as a primary reference or quality control material for microbeam U‐Pb, Hf and Zr isotope measurements because of its slight heterogeneity. The U‐Pb, Hf and Zr isotopic compositions of the SLZB and SLZC megacrysts were homogeneous. The O isotopic compositions in the SLZA and SLZB zircon were slightly dispersed, indicating that these two megacrysts can only serve as secondary reference materials for microbeam O isotope measurements. [ABSTRACT FROM AUTHOR]

We developed a focal guidance system based on a thin lens approximation to support beam-focusing during microbeam experiments in which the only input parameters are the geometry, lens layout, and lens parameters of doublet-to-quadruplet systems in various couplings. The software separately calculates the X-and Y-axis magnetic fields at convergence, beam traces of any magnetic fields, and matrix elements. The operator does not need to have expertise in beam transport. The software reveals how a beam is focused, and the beam behavior as the magnetic field changes. The parasitic aberration coefficient, which is related to the excitation error, was calculated for an automatic focusing system developed at Tohoku University. Calculations were performed for typical doublet-to-quadruplet lens systems; the magnetic fields at convergence were within 1% of the values calculated by the transport code. In real-world experiments, it is relatively easy to focus the beam on only one axis. By normalizing the X and Y focal lines to the excitation currents in the X focus and Y focus, respectively, the currents for both axes focus are obtained and the user can thus understand how to change the excitation current. This is necessary for beginners who require guidance on the direction in which the excitation current should be changed. Our software will be available from http://web.tohoku.ac.jp/fnl/. [ABSTRACT FROM AUTHOR]

Purpose: To study free vibration and bending analyses of a sandwich microbeam with a functionally graded (FG) porous core and two polymeric face sheets reinforced with graphene nanoplatelets (GPLs). Methods: In this paper, the modified couple stress theory (MCST) and a quasi-3D trigonometric shear deformation beam theory are employed. The resultant material properties are examined using the rules of micromechanical. The equations derived through energy method are solved by Navier's method to obtain the natural frequencies and deflection of the nanobeam for a simply-supported boundary condition. Results: Trueness of the results are justified through comparison with the new recently published materials. Parametric static and dynamic results are presented for investigating effect of significant parameters on the frequencies and deflections of the sandwich microbeam, such as porosity parameter, distribution of the pores, the thickness of the core, volume fraction and distribution pattern of the GPLs, thickness-to-length scale parameter, and foundation coefficients. Conclusions: The results show that the VA distribution type has the biggest deflection and the AV one has the lowest value of static bending. [ABSTRACT FROM AUTHOR]

Purpose: In the present study, the linear and nonlinear vibration characteristic of the microbeam has external mass is studied under different boundary conditions and the 3:1 internal resonance is investigated. Methods: The main equation of the microbeam with mass is derived using the modified couple stress theory and Hamilton's principle. The equations are solved via the perturbation method. Result: It is shown that magnetic force, boundary conditions and mass are significant parameters for microbeam for linear and nonlinear results. In addition, it is illustrated that the hardening nonlinearity is slightly affected by the material length scale. Conclusion: A parametric study is performed for a nonlinear frequency–response curve using variable parameters. The verification of the present results has been carried out by comparing the results of previous works. The simple–simple, the clamped–clamped and the simple–clamped boundary conditions effects are compared. The material length scale parameters, mass, position of the mass and magnetic force effects have been researched on linear and nonlinear natural frequency changing. [ABSTRACT FROM AUTHOR]

Carbon concentration and distribution has a dramatic impact on mechanical properties of steel. The manufacture technology of ancient steel is an important question in archaeometallurgy, especially during medieval times when the production process evolves between indirect and direct modes. Steel is an iron alloy incorporating up to a few % of carbon in weight, heterogeneously clustered in various carbide phases that are usually imaged by metallographic microscopy after acid etching. We have investigated the capability to obtain in a direct, non-destructive way and quantitative maps of carbon in steel samples using the 12C(d,pγ)13C reaction with the simultaneous detection of the emission of the 3089 keV γ-ray (d-PIGE) and of the p 0 proton group (d-NRA). Carbon spot measurements and mappings were carried out using an external deuteron microbeam of 1.5 MeV at the New AGLAE facility of the Centre de Recherche et de Restauration des Musées de France. The beam diameter on the target was around 50 µm and its mean intensity 4nA, monitored by using the PIXE signal (Fe K α line) emitted by the sample. Spectra were fitted using the SIMNRA program and the calculated composition checked against standard reference steel targets. Carbon distribution maps were extracted from the collected γ-ray and proton spectra datacubes. Spot measurements acquired in 2 min yielded a limit of detection of 200 ppm carbon weight for d-PIGE and 10 ppm for d-NRA. Proton detection appeared more effective than γ-ray detection owing to better statistics, mainly due to higher detection efficiency and better S/N ratio while γ-rays detection is affected by the spurious emission from nitrogen contained in the exit foil. Carbon concentration was mapped on a medieval archaeological iron alloy sample (140 × 32 points, 7 mm × 1.6 mm area) using a 1.6 sec dwell time, yielding a carbon content of 0.395 % with an uncertainty of 10 %. Heterogeneities could be evidenced in the maps, and incidentally the presence of oxygen. A simple methodology was developed to derive the depth distribution maps of carbon in the first microns of the sample. [ABSTRACT FROM AUTHOR]

To create microelectromechanical systems (MEMS) with a high specific mechanical power, a system "movable electrode–nanoscale gap–thin crystalline film made of a material with a high permittivity–immobile electrode" is used. It is shown that in this system, two-dimensional electromechanical wave emerge. The emergency of such excitations bounds the limit specific power of electromechanical transducer-actuators, MEMS engines and actuators. However, this phenomenon provides numerous possibilities of application of such structures. [ABSTRACT FROM AUTHOR]

Simple Summary: X-ray microbeams are useful tools for elucidating the mechanisms underlying non-target effects, such as the radiation-induced bystander response (RIBR) that occurs under heterogeneous exposure conditions. The microbeam X-ray cell irradiation system at the Central Research Institute of Electric Power Industry (Tokyo, Japan) has been upgraded to enable irradiation with titanium characteristic X-rays (TiK X-rays), which have a longer penetration distance than aluminum characteristic X-rays. The beam size of the TiK X-rays was elliptical, with a long diameter of 7.5 μm and a short diameter of 6.9 μm. The dose rate at the sample position was approximately 0.8 Gy/min. Using this system, we irradiated the nuclei of HeLa cells with high precision and then analyzed RIBR. The percentage of bystander cells with pan-nuclear induction of phosphorylated histone H2AX on serine 139 (γ-H2AX) was significantly increased in one field of view, including microbeam-irradiated cells 180 and 360 min after TiK X-ray microbeam irradiation. Radiation-induced bystander response (RIBR) is a response induced in non-irradiated cells that receive bystander signals from directly irradiated cells. X-ray microbeams are useful tools for elucidating the mechanisms underlying RIBR. However, previous X-ray microbeams used low-energy soft X-rays with higher biological effects, such as aluminum characteristic X-rays, and the difference from conventional X-rays and γ-rays has often been discussed. The microbeam X-ray cell irradiation system at the Central Research Institute of Electric Power Industry has been upgraded to generate higher energy titanium characteristic X-rays (TiK X-rays), which have a longer penetration distance sufficient to irradiate 3D cultured tissues. Using this system, we irradiated the nuclei of HeLa cells with high precision and found that the pan-nuclear induction of phosphorylated histone H2AX on serine 139 (γ-H2AX) in the non-irradiated cells increased 180 and 360 min after irradiation. We established a new method to quantitatively evaluate bystander cells, using the fluorescence intensity of γ-H2AX as an indicator. The percentage of bystander cells increased significantly to 23.2% ± 3.2% and 29.3% ± 3.5% at 180 and 360 min after irradiation, respectively. Our irradiation system and the obtained results may be useful for studies of cell competition as well as non-targeted effects. [ABSTRACT FROM AUTHOR]

The present investigation focuses on the design and mathematical modeling of a microelectromechanical (MEMS) mode-localized based sensor/actuator system. This device incorporates a sensitive clamped–clamped shallow arch microbeam with an initial curvature shaped to resemble one of the first two symmetric and asymmetric modes of free oscillations of a clamped–clamped beam. The analysis reveals that with a suitable arrangement of the initial shape of the device flexible electrode and a proper tuning of the maximum initial rise and the actuating dc load enables the transition to display certain bistable behavior. This could be a better choice to build a device with a large stroke. Furthermore, the generated data showed the occurrence of mode-veering, indicating a coupling between the concerned symmetric and asymmetric modes of vibrations, and offering the possibility for such a device to be used as a mode-localized MEMS-based sensor utilizing veering and crossing phenomena. Indeed, where a certain energy is exchanged between symmetric and asymmetric modes of a microbeam, it can be utilized to serve as a foundation for the development of a new class of highly precise resonant sensors that can capture, with a certain level of precision, any of the sensed signal amplitudes.

Simple Summary: With the advancement in microbeam cell irradiation technologies, researchers can now investigate subcellular region irradiation-induced biological responses as well as whether and how they contribute to the overall radiation induced biological effects of individual cells and the cell population. It will be of great value not only in expanding our understanding of the mechanisms of ionizing interaction with cells, but also in the studies of radiation protection and radiotherapy. Radiation-induced biological effects are commonly associated with an increase in reactive free radicals. Nuclear factor erythroid 2-related factor 2 (NRF2) is a master regulator of cellular oxidative stress. We investigated the response of NRF2 signaling to nucleus targeted irradiation using the Single Particle Irradiation System to Cell (SPICE-QST microbeam) facility and evaluated the similarities and differences between irradiating the cytoplasm or nucleus in the stimulation of NRF2 signaling. Nuclear factor (erythroid-derived 2)-like 2 (NRF2), well-known as a master antioxidative response regulator in mammalian cells, is considered as a potential target for radiation protection and cancer therapy sensitization. We examined the response of NRF2 signaling in normal human lung fibroblast WI-38 cells to nucleus targeted irradiation by 3.4 MeV proton microbeam. Nucleus targeted irradiation stimulated the nucleus accumulation of NRF2 and the expression of its target gene, heme oxygenase 1 (HO-1). The nucleus accumulation of NRF2 increased from 3 h to 12 h post 500 proton irradiation. In the 500 protons range, higher number of protons resulted in increased NRF2 nucleus accumulation. Activating NRF2 with tert-butylhydroquinone reduced DNA double-strand break (DSB) formation in nucleus targeted irradiation by 15%. Moreover, ATM phosphorylation was found in nucleus targeted irradiation. Inhibiting ATM with ku55933 prevented NRF2 nucleus accumulation. Furthermore, nucleus targeted irradiation activated ERK 1/2, and ROS-ERK 1/2 signaling regulated NRF2 nucleus accumulation. Taken together, NRF2 signaling was activated by nucleus targeted irradiation and mitigated DNA DSB. The discovery of ATM and ERK 1/2 as upstream regulators of NRF2 signaling in nucleus targeted cells revealed new information regarding radiation protection. [ABSTRACT FROM AUTHOR]

In order to investigate the correlation between biological functions and trace elements, we have developed a spectroscopic mapping system for ion beam induced fluorescence (IBIF) analysis using a spectrometer and a CCD-based spectrometer and a photon counting type spectrometer based on a multi-pixel photon counter (MPPC) array. Biological functions and trace elements are closely related. To study this relationship, biological functions and trace elements must be mapped to the same positional coordinates. Our new IBIF analysis system, developed at the Dynamitron Laboratory of Tohoku University, has a high-speed capability of detection of IBIF by the fast response of the MPPC and a better signal-to-noise ratio (SNR) of imaging capability by the detection of fluorescence induced by the proton microprobe. As an evaluation trial, the IBIF analysis of the phosphor of cathode ray tube TV samples was performed. It was shown that spectral mapping is possible with the developed system. [ABSTRACT FROM AUTHOR]

The functions of organisms are performed by various tissues composed of different cell types. Localized irradiation with heavy-ion microbeams, which inactivate only a portion of the constituent cells without destroying the physical intercellular connections of the tissue, is a practical approach for elucidating tissue functions. However, conventional collimated microbeams are limited in the shape of the area that can be irradiated. Therefore, using a focused heavy-ion microbeam that generates a highly precise beam spot, we developed a technology to uniformly irradiate specific tissues of an organism with a defined dose, which conventional methods cannot achieve. The performance of the developed paint irradiation technology was evaluated. By irradiating the CR-39 ion track detector, we confirmed that the new method, in which each ion hit position is placed uniformly in the irradiated area, makes it possible to uniformly paint the area at a specified dose. The targeted irradiation of the pharynx and gonads of living Caenorhabditis elegans demonstrated that the irradiated ions were distributed in the same shape as the targeted tissue observed under a microscope. This technology will elucidate biological mechanisms that are difficult to analyze with conventional collimated microbeam irradiation.

We describe a methodology to manipulate Caenorhabditis elegans (C. elegans) and irradiate the stem progenitor gonad region using three MeV protons at a specific developmental stage (L1). The consequences of the targeted irradiation were first investigated by considering the organogenesis of the vulva and gonad, two well-defined and characterized developmental systems in C. elegans. In addition, we adapted high-throughput analysis protocols, using cell-sorting assays (COPAS) and whole transcriptome analysis, to the limited number of worms (>300) imposed by the selective irradiation approach. Here, the presented status report validated protocols to (i) deliver a controlled dose in specific regions of the worms; (ii) immobilize synchronized worm populations (>300); (iii) specifically target dedicated cells; (iv) study the radiation-induced developmental alterations and gene induction involved in cellular stress (heat shock protein) and cuticle injury responses that were found.

Purpose: Spatially Fractionated Radiation Therapy (SFRT) is characterized by large differences in peak and valley doses. Preclinical and clinical studies suggest that differences in biological mechanisms lead to differential normal tissue and tumor response compared to uniform irradiation. We hypothesize that to evaluate clinical effectiveness and understand fundamental biological mechanisms, radiobiological rather than physical dose quantities should be utilized for comparisons. The aim of this work is to determine whether Equivalent Uniform Dose (EUD) is a superior predictor of cell survival than absorbed dose.Methods: Absorbed dose parameters were compared to the Equivalent Uniform Dose to assess their predictive value for the relative effectiveness of uniform and SFRT with X-rays. A Bayesian bootstrap technique was utilized to model uncertainties in the biological fit parameters for a human fibroblast (MRC5) and two human tumor cell lines (LN18 and A549). Dose uncertainties were evaluated through measurements and error modeling of SFRT profiles. A dimensionless Relative Effectiveness Factor (REF) is proposed to quantify differences between uniform and SFRT irradiation.Results: For all cell lines, cell survival after SFRT matched uniform irradiation within the estimated uncertainties at equal values of the EUD. Average and peak dose showed poor correlation with in vitro cell survival. The proposed REF factor is dose dependent and suggests enhanced cell killing for both tumor cell lines (1.14 ± .08 for LN18, 1.32 ± .13 for A549 at 8 Gy EUD) for SFRT. Normal human fibroblasts showed reduced cell killing relative to uniform irradiation (.58 ± .06 for MRC5). Synthetically generated SFRT dose profiles revealed that EUD uncertainties are dominated by valley dose uncertainties, especially at high doses.Discussion: EUD is more predictive of cell survival than average or valley dose. Valley dose is close to equal to the EUD for values >10 Gy and has the advantage of being independent of uncertainties in biological parameters. The REF is a novel and useful metric to compare quantitative differences in SFRT and uniform irradiation.Conclusion: EUD is recommended for comparisons of SFRT and uniform irradiation. The results suggest an increase in survival of normal-human fibroblast cells and reduced survival for both tumor cell lines after SFRT relative to uniform irradiation.

Simple Summary: The present paper introduces a radiobiological phenomenon known as the Radiation-Induced Rescue Effect (RIRE), where the radiobiological effects developed in cells irradiated with ionizing radiations are mitigated by non-irradiated cells. The primary objective of a radiotherapy treatment is to kill cancer cells with ionizing radiation while at the same time sparing the normal cells. However, RIRE was found capable of saving some of the irradiated cancer cells, so the efficacy and outcome of radiotherapy might be undermined. As such, it would be pertinent to have a better understanding of RIRE, including its underlying mechanisms and its relationships with other non-traditional radiobiological phenomena. Microbeam irradiations have some unique features that could help research on RIRE, which are explained. The paper also reviews the insights gained from previous microbeam experiments on RIRE. Some thoughts on future priorities and directions of research on RIRE exploiting unique features of microbeam radiations are presented in the last section. The present paper reviews a non-targeted effect in radiobiology known as the Radiation-Induced Rescue Effect (RIRE) and insights gained from previous microbeam experiments on RIRE. RIRE describes the mitigation of radiobiological effects in targeted irradiated cells after they receive feedback signals from co-cultured non-irradiated bystander cells, or from the medium previously conditioning those co-cultured non-irradiated bystander cells. RIRE has established or has the potential of establishing relationships with other non-traditional new developments in the fields of radiobiology, including Radiation-Induced Bystander Effect (RIBE), Radiation-Induced Field Size Effect (RIFSE) and ultra-high dose rate (FLASH) effect, which are explained. The paper first introduces RIRE, summarizes previous findings, and surveys the mechanisms proposed for observations. Unique opportunities offered by microbeam irradiations for RIRE research and some previous microbeam studies on RIRE are then described. Some thoughts on future priorities and directions of research on RIRE exploiting unique features of microbeam radiations are presented in the last section. [ABSTRACT FROM AUTHOR]

Here we review probing biological processes initiated by the deposition of droplets on surfaces by micro- and nanobeam X-ray scattering techniques using synchrotron radiation and X-ray free-electron laser sources. We review probing droplet evaporation on superhydrophobic surfaces and reactions with substrates, basics of droplets deposition and flow simulations, droplet deposition techniques and practical experience at a synchrotron beamline. Selected applications with biological relevance will be reviewed and perspectives for the latest generation of high-brilliance X-ray sources discussed.

In this study, the free vibration analysis of a functionally graded (FG) microbeam with tapered cross-section was carried out theoretically. The beam has material distribution according to the power law throughout the thickness. The governing equation was reduced to an ordinary differential equation for a tapered beam with cross-sectional geometry whose width varies exponentially. Vibrations of a FG tapered microbeam was analyzed analytically in the elastic variation range based on the modified stress couple theory. Motion equations and boundary conditions were derived from the Hamilton principle. Analytical results of natural frequencies were calculated for cantilever exponential FG beams. Solutions for natural frequencies were obtained as the ratio of the beam's characteristic size to the material internal length parameter and according to the FGM distribution function characteristics.

[Display omitted] • A 3D numerical study was conducted on a micromixer with an oscillating microbeam. • Effects of oscillation frequency and Reynolds number on mixing were investigated. • The optimum operating condition was found for this micromixer. • Four novel designs were proposed by adding passive techniques to this micromixer. • The maximum mixing index was 88% in 0.4 s. In this research, we numerically studied a three-dimensional (3-D) T-shaped active micromixer which works based on the oscillations of a cantilever microbeam. We explored the influence of microbeam's oscillation frequency (10–40 Hz) and flow Reynolds number (2.5–30) on mixing performance, revealing optimal operating conditions. Under optimal operating conditions, using a simple microbeam in a short straight microchannel, the micromixer achieved a 76.7 % mixing index within just 0.4 s. In the next part of this paper, we introduced modifications to the microbeam and microchannel geometries to enhance mixing performance further. Adding a circular part to the channel improved the mixing index to 85.7 %. In a more complex configuration, characterized by a perforated microbeam and a circular microchannel, the micromixer achieved its highest efficiency of 88 %. Additionally, a novel configuration employing two microbeams within a straight channel achieved a mixing efficiency of 82.2 %. [ABSTRACT FROM AUTHOR]

Micro-electromechanical systems (MEMS) devices contain various mechanical components to have mechanical movement of the MEMS structure, such as the microcantilever beam. In this work, we present the new design of a microcantilever beam based on the regular hexagon shape and the conventional microcantilever beam. Experimental, analytical, and numerical analyses have been carried out for both configurations. Silicon dioxide (SiO 2) based microcantilever beams are fabricated using wet bulk micromachining. The thickness and width of the beams are kept constant at 0. 96 μ m and 35 μ m , respectively. In contrast, the length of the beam varies based on the number of hexagonal unit cells used. Here, we considered single, double, triple, quadruple, and quintuple hexagonal microbeams for the analyses. The new designs are analyzed for natural frequency, maximum deflection, and Q-factor in the first transverse vibration mode and compared with the equivalent uniform rectangular beams. Due to reduced stiffness, the first mode natural frequency of hexagon beams is lower than the equivalent uniform beams. The static deflection analysis has been performed numerically by applying a normal load of 10 nN at a free end of the beams. The maximum deflection of quadruple and quintuple hexagonal beams is found 450% and 438%, respectively, higher than the uniform beams due to a reduction in stiffness. In addition, the quality factor has been obtained for various damping mechanisms in ambient conditions. From the results obtained, it is observed that the quality factor associated with drag force damping is more dominant over other damping mechanisms. The experimentally measured quality factor has been compared with semi-analytical boundary element methods (BEM) and finite element based method in ANSYS. The values were found to be of the same order of magnitude. Due to the higher flexibility and excellent damping characteristics, the proposed hexagonal microbeams have potential applications as MEMS devices. However, its length and number of arrays can be optimized to minimize the sagging of the beam to the bottom substrate at the end. After analyzing the influence of pressure on structures consisting of hexagon beams and square membrane experimentally and numerically, we investigated the potential application of the suggested hexagonal beams as suspension springs in in-plane as well as out-of-plane MEMS accelerometers across different widths of the microbeams. [Display omitted] • Feasibility of fabricating different units of a hexagonal beam and its arrays are analyzed. • Frequency reduces and flexibility increases by around 75% using hexagonal beams. • Frequency change of around 50% can be obtained using inverse hexagonal shape. • Quality factor change of around 70% is found using inverse hexagonal shape. • Arrays of hexagonal units give near similar results as that of uniform beam of same length. [ABSTRACT FROM AUTHOR]

We investigated the applicability of Ion Beam Induced Luminescence (IBIL) analysis for identifying biological components in sequentially collected airborne particulate matter (PM) samples obtained using the automated sampler. A series of micro-IBIL spectroscopies were performed on a PTFE (polytetrafluoroethylene) membrane tape filter from the Atmospheric Environmental Regional Observation System (AEROS) during a highly concentrated air pollution event on 26–27 March 2020, collected at Ota, Japan (36.290°n, 139.381°e) using an external 3 MeV proton microprobe. IBIL at typical wavelengths associated with organic compounds such as NADH and riboflavin were identified through the series of IBIL analyses, which is a key factor for identifying existence of organic pollutions, or bioaerosols. The decay times of the IBIL indicate that the peak measured is due to organic compounds rather than inorganic particles or ambient substances. These results suggest that micro-IBIL spectroscopy can be used to identify bioaerosols in hourly collected AEROS PTFE membrane tape filters taken from the atmosphere. [ABSTRACT FROM AUTHOR]

Radiation-induced bystander response (RIBR) is a response induced in non-irradiated cells that receive bystander signals from directly irradiated cells. X-ray microbeams are useful tools for elucidating the mechanisms underlying RIBR. However, previous X-ray microbeams used low-energy soft X-rays with higher biological effects, such as aluminum characteristic X-rays, and the difference from conventional X-rays and γ-rays has often been discussed. The microbeam X-ray cell irradiation system at the Central Research Institute of Electric Power Industry has been upgraded to generate higher energy titanium characteristic X-rays (TiK X-rays), which have a longer penetration distance sufficient to irradiate 3D cultured tissues. Using this system, we irradiated the nuclei of HeLa cells with high precision and found that the pan-nuclear induction of phosphorylated histone H2AX on serine 139 (γ-H2AX) in the non-irradiated cells increased 180 and 360 min after irradiation. We established a new method to quantitatively evaluate bystander cells, using the fluorescence intensity of γ-H2AX as an indicator. The percentage of bystander cells increased significantly to 23.2% ± 3.2% and 29.3% ± 3.5% at 180 and 360 min after irradiation, respectively. Our irradiation system and the obtained results may be useful for studies of cell competition as well as non-targeted effects.

In this work, we studied and optimized the performance of electrostatic quadruple focusing lens system. Combining the power of three simulation software, we explored the lens hyper-parameter space to maximize the Figure of Merit Q that is proportional to the magnitude of the product of the horizontal and vertical demagnifications and inversely proportional to the product of the spherical aberration coefficients. For a 3 MeV/q beam with beam emittance of 0.2 μm·mrad, the most compact and high-performance system we obtained was an electrostatic quadruple triplet (EQT), which had a Q value of 24 and a length of ∼0.5 m, measured from the divergence slit to the end of the last set of electrodes. Increasing the distance l between the divergence aperture and the first lens further increased the Q value. l = 1.0 m seems to be a good trade-off between maximizing the Q value and minimizing the system length, under which Q was approximately 33. [ABSTRACT FROM AUTHOR]

In this work, a modified viscoelastic model of initially stressed microbeam on the base of the Winkler foundation under the effect of ultrafast laser heating and axial stress has been proposed. Viscosity effects are taken into account following the Kelvin–Voigt model. The governing equation for the thermoelastic vibration of the microbeam is obtained when the thermal field effect is defined by the non-Fourier Moore–Gibson–Thompson (MGT) heat equation. The microbeam is seen as an Euler–Bernoulli beam that is exposed to varying sinusoidal heat. An analytical solution to the problem has been presented on the basis of the Laplace transform in addition to applying a numerical method to find inverse transformations. A numerical illustration is organized in the discussion section which discusses the impact of different effective parameters both on the vibrational behavior of a microbeam system and on the field variables. The viscous damping coefficient, laser pulse duration, and axial load greatly affect the deflection and temperature responses. The results obtained are verified and compared with the literature. [ABSTRACT FROM AUTHOR]

This paper presents dynamic analysis of a simply supported porous microbeam made of functionally graded materials subjected to a moving load. Material properties of the porous microbeam change in the thickness direction according to power-law distribution with different porosity models. The governing equations are obtained by Lagrange procedure based on Bernoulli–Euler beam and modified couple stress theories. Then, the resulting equations are solved by Ritz and Newmark average acceleration methods. A detailed parametric study is performed to investigate the effects of porosity coefficient, porosity distribution, material distribution, and length scale parameter on the dynamic responses of functionally graded porous microbeams. [ABSTRACT FROM AUTHOR]

The motion of a slender, clamped-free, imperfect, electrically actuated microbeam is investigated. Special attention is given to the influence of imperfections and noise on the bifurcations and instabilities of the structure, a problem not tackled in the previous literature on the subject. To this end, a geometrically nonlinear theory is adopted for the microbeam retaining geometric nonlinear terms up to the third order and considering in a consistent way the effect of initial geometric imperfections. Also, additive white noise is considered to model forcing uncertainties, and the Galerkin discretization method, using as interpolating functions the linear vibration modes, is used to obtain a modal stochastic differential equation of Itô type, which is solved by the stochastic Runge–Kutta method. A parametric analysis clarifies the influence of geometric imperfections and noise level on the natural frequencies, resonance curves, and pull-in instability. Additionally, the global dynamics is examined through the generalized cell mapping, showing the effects of uncertainties on the attractor's probability density functions and basins of attraction. [ABSTRACT FROM AUTHOR]

In this paper, the vibration of microbeams due to a temperature pulse has been investigated. The thermoelastic coupled equations for microbeam resonator have been derived via the modified theory of couple stress in connection with the generalized thermoelasticity with relaxation time. The analytical expressions for studied fields due to modified couple stress for the microbeam have been obtained by applying the Laplace transform method. In addition, some comparisons have been displayed in graphs to estimate the effects of different parameters such as the couple stress parameter and pulse of temperature on the considered fields. Numerical conclusions demonstrate that the estimation of deflection expected by the new theory is lower than that of the classical one. Comparisons are made with the results of different models in the absence and presence of couple stress theory. Particular cases of interest are also derived.