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Nitrogen-vacancy (NV-) centers in nanodiamonds have emerged as a versatile platform for a wide range of applications, including bioimaging, photonics, and quantum sensing. However, the widespread adoption of nanodiamonds in practical applications has been hindered by the challenges associated with patterning them into high-resolution features with sufficient throughput. In this work, we overcome these limitations by introducing a direct laser-writing bubble printing technique that enables the precise fabrication of two-dimensional nanodiamond patterns. The printed nanodiamonds exhibit a high packing density and strong photoluminescence emission, as well as robust optically detected magnetic resonance (ODMR) signals. We further harness the spatially resolved ODMR of the nanodiamond patterns to demonstrate the mapping of two-dimensional temperature gradients using high frame rate widefield lock-in fluorescence imaging. This capability paves the way for integrating nanodiamond-based quantum sensors into practical devices and systems, opening new possibilities for applications involving high-resolution thermal imaging and biosensing.

The design of color-tunable upconversion luminescence for expand the application of optical fields has been a hot research topic. Herein, Yb3+, Ho3+ co-doped YNb 1-x V x O 4 (x = 0, 0.25, 0.5, 0.75, 1) are synthesized by solid state method. The color tunability of UC luminescence from green to red is achieved by varying the component ratio of Nb5+ and V5+ in the mixed compositions. The continuous introduction of V5+ component strengthens the vibrational band of the mixed host, thus promoting the non-radiative relaxation of 5I 6 →5I 7 in activator Ho3+, which becomes the key to obtain the color-tunable UC luminescence. Besides, the Ho3+ activated system exhibits strong temperature dependent variation in UC luminescence intensity of 5F 4 /5S 2 →5I 8 and 5F 5 →5I 8. The optimal sensitivity parameters can be obtained as 35.64 × 10−3 K−1 for S A-max and 3.78 % for S R-max in YVO 4 :Yb3+,Ho3+ thermometer. Benefit by the luminescence color tunability and excellent thermometry performance, phosphors with host dependent upconversion of Ho3+ activated system are expected to achieve optical applications in various fields of anti-counterfeiting, display, and temperature sensing. [ABSTRACT FROM AUTHOR]

Fluorescence intensity ratio (FIR) technique has been a promising non-contact thermometry method owing to the characteristics of rapid response and exceptional resolution. In this study, a new iodate phosphor NaYI 4 O 12 :Er3+ (NYIO:Er3+) is synthesized via a microwave-assisted hydrothermal method. It exhibits bright green emission under 380 and 980 nm excitations. The power-dependent upconversion and Er3+ content-dependent downshifting performances are investigated. Excited by 380 nm, the temperature-dependent FIR originating from thermally coupled levels of Er3+ are discussed in detail. The resulting material displays outstanding temperature sensing properties across the temperature range of 298–523 K. The absolute and relative sensitivities can reach the maximum values of 0.51 × 10−2 K−1 and 1.3 % K−1, separately. Meanwhile, the reliability and repeatability of the temperature sensing characteristics are verified. The result demonstrates that the Er3+-activated iodate phosphor NaYI 4 O 12 :Er3+ is a promising candidate in non-contact optical thermometry domain. [Display omitted] [ABSTRACT FROM AUTHOR]

In the recent past, noncontact optical thermometry has flourished as a result of the growing demand for temperature determination. In this work, we presented the first systematic investigation of a novel red phosphor Ca 3 La 2-x W 1.984 O 12 : 0.016Mn4+/ x Dy3+ (CLW: Mn4+/ x Dy3+). Compared with Dy3+, the emitting intensity of Mn4+ decreases more rapidly with increasing temperature. This property enables CLW: 0.016Mn4+/0.08Dy3+ to be used as a fluorescence intensity ratio thermometer with absolute sensitivity (S a) of 0.0364 K−1 at 573 K and relative sensitivity (S r) of 1.551 % K−1 at 473 K. On the other hand, a second temperature sensing model based on the fairly rapid decay of the lifetime is achieved with S r = 1.953 % K−1 at 523 K and S a = 0.0034 K−1 at 448 K. The results of this study suggest that phosphor CLW: 0.016Mn4+/0.08Dy3+ could be useful as optical thermometer material with a temperature range of 298K–573K. [ABSTRACT FROM AUTHOR]

Phosphors with multifunctional applications have attracted extensive research, especially in thermometer and anti‐counterfeiting fields. Herein, a series of Pr3+‐doped YNbO4 (YNO) phosphors with adjustable photoluminescence and red persistent luminescence (PersL) performances are developed. YNO host exhibits the blue self‐activated luminescence, and the different Pr3+ emission peaks possess various thermal stability properties due to the thermal quenching channel generated by the intervalence charge transfer state between Pr3+ and Nb5+ ions. Two kinds of fluorescence intensity ratio models with high absolute and relative sensitivities are realized to measure the temperature under dual‐wavelength excitation. Moreover, YNO:Pr3+ exhibits the red PersL with a duration of about 120 s upon ceasing the UV excitation light source. The fabricated YNO:Pr3+‐polydimethylsiloxane films display different luminescence patterns with the passage of time after turning off UV light, which can cleverly achieve dynamic conversion. These results demonstrate that YNO:Pr3+ phosphor has potential applications in dual‐wavelength excited thermometry and dynamic anti‐counterfeiting fields. [ABSTRACT FROM AUTHOR]

Understanding the microscopic thermal effects of the hydrogel is important for its application in diverse fields, including thermal‐related studies in tissue engineering and thermal management for flexible electronic devices. In recent decades, localized thermal properties, such as thermal conductivity, have often been overlooked due to technical limitations. To tackle this, the study proposes a new hybrid diamond microsensor that is capable of simultaneous temperature control and readout in a decoupled manner. Specifically, the sensor consists of a silicon pillar (heater) at ≈10 microns in length, topped by a micron‐sized diamond particle that contains silicon‐vacancy (SiV) centers (thermometer) with 1.29 KHz−12${\mathrm{K}} {\mathrm{H}}{{{\mathrm{z}}}^{ - \frac{1}{2}}}$ temperature measurement sensitivity. Combining this innovative, scalable sensor with a newly established simulation model that can transform heating‐laser‐induced temperature change into thermal conductivity, an all‐optical decoupled method is introduced with ≈0.05 W m−1 K−1 precision, which can reduce laser crosstalk. For the first time, the thermal conductivity change of hydrogels during the gelation process is tracked and the existence of variation is demonstrated. The study introduces a rapid, undisturbed technique for measuring microscale thermal conductivity, potentially serving as a valuable tool for cellular thermometry, and highlights the idea that decoupling can reduce crosstalk from different lasers, which is helpful for quantum sensing. [ABSTRACT FROM AUTHOR]

The Er3+/Yb3+ co‐doped tellurite glasses and glass‐ceramics (GCs) containing the Gd2Te6O15 phase were successfully fabricated via the conventional melting‐quenching technique followed by a crystallization regime. The Er3+/Yb3+ co‐doped tellurite glasses generated intense up‐conversion green (524 and 546 nm) and red (658 nm) emissions when stimulated by a 980 nm laser. The up‐conversion green emission intensity increased by 68 and 46 times with the increase of the Yb3+/Er3+ ratio, and the optimal Yb3+/Er3+ ratio was found to be 8:1. The surface crystallization process of the Gd2Te6O15 GCs was confirmed through analysis of crystallization kinetics and microscopic morphology. The up‐conversion luminescence and lifetime of Er3+ ions were enhanced by the precipitation of low‐phonon‐energy Gd2Te6O15 crystals. The GC sample crystallized at 480°C for 4 h showed the highest luminescence intensity. The optical thermometry properties of Er3+ ions at thermally coupled energy levels (2H11/2/4S3/2→4I15/2) were explored. The Gd2Te6O15 GCs co‐doped with 0.25 mol% Er2O3 and 2.0 mol% Yb2O3 exhibited an excellent temperature relative sensitivity (Sr) of 1.22% K−1 at 293 K and a great repeatability of 98.07%. These results suggest that the Er3+/Yb3+ co‐doped Gd2Te6O15 GCs show promise for optical thermometry. [ABSTRACT FROM AUTHOR]

Thermal heating of biological samples allows to reversibly manipulate cellular processes with high temporal and spatial resolution. Manifold heating techniques in combination with live‐cell imaging were developed, commonly tailored to customized applications. They include Peltier elements and microfluidics for homogenous sample heating as well as infrared lasers and radiation absorption by nanostructures for spot heating. A prerequisite of all techniques is that the induced temperature changes are measured precisely which can be the main challenge considering subcellular structures or multicellular organisms as target regions. This article discusses heating and temperature sensing techniques for live‐cell imaging, leading to future applications in cell biology. [ABSTRACT FROM AUTHOR]

Over the past three decades, luminescence thermometry has gained significant attention among researchers and practitioners. The method has progressed in terms of utilizing temperature-sensitive luminescent materials, obtaining temperature read-outs from luminescence, developing applications, and improving performance. This paper reviews and critically analyzes routes for improving luminescence thermometry performance, in particular the sensitivity, accuracy, and precision of the method. These include the use of highly temperature-sensitive probes, temperature read-outs from luminescence with improved sensitivity, multiparameter temperature-reading methods, the applications of principal component analysis and artificial neural networks, and sensor fusion. [ABSTRACT FROM AUTHOR]

Objective: Epileptogenesis is linked to neuroinflammation. We hypothesized that local heat production caused by neuroinflammation can be visualized non‐invasively in vivo via brain magnetic resonance spectroscopic imaging (MRSI) and MRSI‐thermometry (MRSI‐t) and that there is a relationship in patients with temporal lobe epilepsy (TLE) between MRSI‐t and brain metabolites choline and myo‐inositol and between neuroimaging and cellular and serum biomarkers of inflammation. Methods: Thirty‐six (36) participants, 18 with temporal lobe epilepsy (13 females) and 18 age‐matched healthy controls (nine females), were enrolled prospectively and underwent MRSI/MRSI‐t; TLE participants also provided blood samples. Temperature was measured using creatine as a reference metabolite. Analysis of Functional NeuroImages 3dttest++ tool was used to analyze voxel‐level group differences in temperature, choline, and myo‐inositol. Associations with immune cell subsets, cytokines, and chemokines related to inflammation were quantified using correlation coefficients with significant relationships as noted. Results: Patients with TLE showed elevated temperature, choline, and myo‐inositol in the temporal lobes. Higher brain temperature was associated with higher levels of cytokines and chemokines, including GM‐CSF, TNF, IL‐1β, and IL − 12p70, and lower frequency of immune cells including CD3+ T‐cells, CD4+ T‐cells, CD8+ T‐cells, and classical monocytes. Higher choline was associated with higher levels of the cytokines including LT‐α, IL‐13, and IL‐4, and higher myo‐inositol was associated with a higher frequency of CD4+ T‐cell and CD19+ B‐cell subsets and higher levels of cytokines and chemokines including LT‐α, IL‐13, and CCL3. Significance: This study, for the first time, showed that in temporal lobes of patients with TLE temperature and metabolite changes correlate with cellular and serum biomarkers of inflammation. Our results provide support for further development of MRSI‐t as a measure of neuroinflammation in epilepsy and potentially other neurological disorders and as an investigative and clinical tool. Plain Language Summary: Neuroinflammation is associated with excessive heat production which can be visualized with magnetic resonance spectroscopic imaging and thermometry (MRSI‐t). We prospectively investigated the relationship between MRSI‐t and cellular and serum measures of peripheral inflammation in patients with temporal lobe epilepsy (TLE); we compared the results of MRSI‐t in patients with TLE to healthy controls. We showed a relationship between the temperature elevations in TLE and elevations of various measures of peripheral inflammation. Our results support further development of MRSI‐t as a measure of neuroinflammation in epilepsy and potentially other neurological disorders and as an investigative and clinical tool. [ABSTRACT FROM AUTHOR]

Temperature sensing at the nanoscale is a significant experimental challenge. Here, an approach using dressed states is reported to make a leading quantum sensor – the nitrogen‐vacancy (NV) center in diamond – selectively sensitive to temperature, even in the presence of normally confounding magnetic fields. Using an experimentally straightforward approach, the magnetic sensitivity of the NV center is suppressed by a factor of seven, while retaining full temperature sensitivity and narrowing the NV center linewidth. These results demonstrate the power of engineering the sensor Hamiltonian using external control fields to enable sensing with improved specificity to target signals. [ABSTRACT FROM AUTHOR]

Background: T1 thermometry is considered a straight method for the safety monitoring of patients with deep brain stimulation (DBS) electrodes against radiofrequency-induced heating during Magnetic Resonance Imaging (MRI), requiring different sequences and methods. Objective: This study aimed to compare two T1 thermometry methods and two low specific absorption rate (SAR) imaging sequences in terms of the output image quality. Material and Methods: In this experimental study, a gel phantom was prepared, resembling the brain tissue properties with a copper wire inside. Two types of rapid gradient echo sequences, namely radiofrequency-spoiled and balanced steadystate free precession (bSSFP) sequences, were used. T1 thermometry was performed by either T1-weighted images with a high SAR sequence to increase heating around the wire or T1 mapping methods. Results: The balanced steady-state free precession (bSSFP) sequence provided higher image quality in terms of spatial resolution (1×1×1.5 mm³ compared with 1×1×3 mm³) at a shorter acquisition time. The susceptibility artifact was also less pronounced for the bSSFP sequence compared with the radiofrequency-spoiled sequence. A temperature increase, of up to 8 °C, was estimated using a high SAR sequence. The estimated change in temperature was reduced when using the T1 mapping method. Conclusion: Heating induced during MRI of implanted electrodes could be estimated using high-resolution T1 maps obtained from inversion recovery bSSFP sequence. Such a method gives a direct estimation of heating during the imaging sequence, which is highly desirable for safe MRI of DBS patients. [ABSTRACT FROM AUTHOR]

Photothermal therapy (PTT) is a type of cancer treatment capable of damaging tumors using laser irradiation. This procedure can be a promising approach to complement current cancer therapies, due in part to its minimal invasiveness. One of the challenges of photothermal therapy is the potential collateral damage to the surrounding healthy tissue, as well as excessive temperature increase in the target tumor region that can cause tissue carbonization and evaporation. With the aim of increasing the performance of photothermal therapy in damaging targeted tumor while keeping healthy nearby tissue unaffected, this research proposes the use of a feedback control system that considers the cumulative thermal damage to both types of tissue. Two separate control algorithms (fuzzy logic and PI) were designed and tested in silico using simulations made in MATLAB® and Python. Results showed that both controllers successfully accomplished the proposed goals. Therefore, the feasibility of using these automated systems to improve the efficacy and safety of PTT was demonstrated. [ABSTRACT FROM AUTHOR]

Background Purpose Methods Results Conclusion Quantitative real‐time MRI‐based temperature mapping techniques are hampered by abdominal motion. Intrascan motion can be reduced by rapid acquisition sequences such as 2D echo planar imaging (EPI), and inter‐scan organ displacement can be compensated by image processing such as optical flow (OF) algorithms. However, motion field estimation can be seriously affected by local variation of signal intensity on magnitude images inherent to tissue heating, potentially leading to erroneous temperature estimates.This study aims to characterize, in the context of clinical MRI‐guided microwave ablation (MWA), a novel deformable image registration (DIR) algorithm that enhances the generation of thermal maps aligned to a reference position, a critical step for calculating cumulative thermal dose and, consequently, for the real‐time evaluation of interventional procedure progress.A retrospective image analysis was performed on 11 patients that underwent MWA of a liver tumor (primary or metastasis). Ablation duration was set to 9 ± 2 min with a 14‐gauge large antenna. A stack of 13–20 contiguous slices was acquired dynamically (350 repetitions) at 1.5T using a single‐shot EPI sequence. Evaluation was first performed on motion‐free datasets (5 gated acquisitions using a cushion positioned in the patient abdomen) then with ones with motion (8 fixed‐frequency acquisitions at 0.5 Hz). Temperature, thermal dose and lesion size were computed using three workflows: (i) standard phase subtraction (gold standard), (ii) conventional OF motion compensation, (iii) PCA‐based OF motion compensation. The impact of flow field, temperature and lesion volume estimation were compared using averaged endpoint error (AEE), NRMSE and bland Altman plot, respectively.Intensity signal decreases (close to 50%) were observed in the vicinity of the probe during MW energy delivery. Both motion correction algorithms reduce the NRMSE of magnitude images throughout the acquisition (p < 0.005) and achieve similar results between them. Gated acquisition results. Conventional OF produced erroneous vector fields compared to the PCA‐based OF, leading to higher maximal EE (3 mm vs. 1 mm) and temperature errors up to 15°C–20°C. PCA‐based OF algorithm significantly reduces the NRMSE of temperature (p < 0.005). The conventional OF method underestimated the final size of lesions with a bias of 0.93 cm3 while the PCA‐based OF reported a bias of 0.5 cm3. Fixed frequency acquisition results. The temperature estimation without motion correction led to strong fluctuations or loss of temperature measurement while the proposed PCA‐based OF recovered both a stable and precise measurement with null bias.The deformable image registration algorithm is less sensitive to local variations of the signal. Volumetric temperature imaging without gating (20 slices/2 s) could be performed with the same accuracy, and offer trade‐offs in acquisition time or volume coverage. Such a strategy is expected to increase procedure safety by monitoring large volumes more rapidly for MR‐guided thermotherapy on mobile organs. [ABSTRACT FROM AUTHOR]

In recent years, phosphors have been used in the field of temperature sensing, which has aroused great interest because of its advantages of quick response, high sensitivity and high accuracy. However, exploring optical thermometers with ultra-high sensitivity remains a challenge. In this work, we have designed and synthesized Sm3+ and Mn4+ co-doped La 3 Mg 2 NbO 9 phosphor for temperature sensing for the first time by utilizing the anomalous thermal quenching property of Sm3+ ions and the sensitive thermal quenching property of Mn4+ ions. Furthermore, the structure, elemental distribution, morphology and optical characteristics of La 3 Mg 2 NbO 9 :Sm3+,Mn4+ were studied in detail. Benefiting from the different responses of the Sm3+ and Mn4+ ions to temperature, the fluorescence intensity ratios of Sm3+ to Mn4+ in La 3 Mg 2 NbO 9 samples show excellent optical thermometry performance in the range of 303–463 K. The maximum absolute sensitivity (S a) and relative sensitivity (S r) values of La 3 Mg 2 NbO 9 :Sm3+,Mn4+ sample reach as high as 0.117 K-1 (@463 K) and 4.48 % K−1 (@303 K), respectively. Furthermore, the maximum of S a is 0.385 K−1 (@463 K) and the maximum of S r is 4.54 % K−1 (@303 K) based on the fluorescence lifetime temperature measurement method. The temperature cyclotron curve of the sample proves that the sample has excellent stability and repeatability in temperature measurement. These results demonstrate that the designed La 3 Mg 2 NbO 9 :Sm3+,Mn4+ phosphor is promising for the field of non-contact optical temperature thermometry. [ABSTRACT FROM AUTHOR]

Accurate temperature measurement is critical across various scientific and industrial applications, necessitating advancements in thermometry techniques. This study explores luminescence thermometry, specifically utilizing machine learning methodologies to enhance temperature sensitivity and accuracy. We investigate the performance of principal component analysis (PCA) on the Eu3+-doped Y2Mo3O12 luminescent probe, contrasting it with the traditional luminescence intensity ratio (LIR) method. By employing PCA to analyze the full emission spectra collected at varying temperatures, we achieve an average accuracy (ΔT) of 0.9 K and a resolution (δT) of 1.0 K, significantly outperforming the LIR method, which yielded an average accuracy of 2.3 K and a resolution of 2.9 K. Our findings demonstrate that while the LIR method offers a maximum sensitivity (Sr) of 5‰ K⁻1 at 472 K, PCA's systematic approach enhances the reliability of temperature measurements, marking a crucial advancement in luminescence thermometry. This innovative approach not only enriches the dataset analysis but also sets a new standard for temperature measurement precision. [ABSTRACT FROM AUTHOR]

Background: T1 thermometry is considered a straight method for the safety monitoring of patients with deep brain stimulation (DBS) electrodes against radiofrequency-induced heating during Magnetic Resonance Imaging (MRI), requiring different sequences and methods.Objective: This study aimed to compare two T1 thermometry methods and two low specific absorption rate (SAR) imaging sequences in terms of the output image quality.Material and Methods: In this experimental study, a gel phantom was prepared, resembling the brain tissue properties with a copper wire inside. Two types of rapid gradient echo sequences, namely radiofrequency-spoiled and balanced steady-state free precession (bSSFP) sequences, were used. T1 thermometry was performed by either T1-weighted images with a high SAR sequence to increase heating around the wire or T1 mapping methods.Results: The balanced steady-state free precession (bSSFP) sequence provided higher image quality in terms of spatial resolution (1×1×1.5 mm3 compared with 1×1×3 mm3) at a shorter acquisition time. The susceptibility artifact was also less pronounced for the bSSFP sequence compared with the radiofrequency-spoiled sequence. A temperature increase, of up to 8 ℃, was estimated using a high SAR sequence. The estimated change in temperature was reduced when using the T1 mapping method. Conclusion: Heating induced during MRI of implanted electrodes could be estimated using high-resolution T1 maps obtained from inversion recovery bSSFP sequence. Such a method gives a direct estimation of heating during the imaging sequence, which is highly desirable for safe MRI of DBS patients.

Aim: Focused ultrasound (FUS) therapies are often performed within magnetic resonance imaging (MRI) systems providing thermometry-based temperature monitoring. Herein, MRI thermometry was assessed for FUS sonications executed using a preclinical system on agar-based phantoms at 1.5T and 3T MRI scanners, using the proton resonance frequency shift technique. Materials and Methods: Sonications were executed at 1.5T and 3T to assess the system and observe variations in magnetic resonance (MR) thermometry temperature measurements. MR thermometry was assessed at 3T, for identical sonications on three agar-based phantoms doped with varied silica and evaporated milk concentrations, and for sonications executed at varied acoustic power of 1.5–45 W. Moreover, echo time (TE) values of 5–20 ms were used to assess the effect on the signal-to-noise ratio (SNR) and temperature change sensitivity. Results: Clearer thermal maps with a 2.5-fold higher temporal resolution were produced for sonications at 3T compared to 1.5T, despite employment of similar thermometry sequences. At 3T, temperature changes between 41°C and 50°C were recorded for the three phantoms produced with varied silica and evaporated milk, with the addition of 2% w/v silica resulting in a 20% increase in temperature change. The lowest acoustic power that produced reliable beam detection within a voxel was 1.5 W. A TE of 10 ms resulted in the highest temperature sensitivity with adequate SNR. Conclusions: MR thermometry performed at 3T achieved short temporal resolution with temperature dependencies exhibited with the sonication and imaging parameters. Present data could be used in preclinical MRI-guided FUS feasibility studies to enhance MR thermometry.

Abstract Objective Epileptogenesis is linked to neuroinflammation. We hypothesized that local heat production caused by neuroinflammation can be visualized non‐invasively in vivo via brain magnetic resonance spectroscopic imaging (MRSI) and MRSI‐thermometry (MRSI‐t) and that there is a relationship in patients with temporal lobe epilepsy (TLE) between MRSI‐t and brain metabolites choline and myo‐inositol and between neuroimaging and cellular and serum biomarkers of inflammation. Methods Thirty‐six (36) participants, 18 with temporal lobe epilepsy (13 females) and 18 age‐matched healthy controls (nine females), were enrolled prospectively and underwent MRSI/MRSI‐t; TLE participants also provided blood samples. Temperature was measured using creatine as a reference metabolite. Analysis of Functional NeuroImages 3dttest++ tool was used to analyze voxel‐level group differences in temperature, choline, and myo‐inositol. Associations with immune cell subsets, cytokines, and chemokines related to inflammation were quantified using correlation coefficients with significant relationships as noted. Results Patients with TLE showed elevated temperature, choline, and myo‐inositol in the temporal lobes. Higher brain temperature was associated with higher levels of cytokines and chemokines, including GM‐CSF, TNF, IL‐1β, and IL − 12p70, and lower frequency of immune cells including CD3+ T‐cells, CD4+ T‐cells, CD8+ T‐cells, and classical monocytes. Higher choline was associated with higher levels of the cytokines including LT‐α, IL‐13, and IL‐4, and higher myo‐inositol was associated with a higher frequency of CD4+ T‐cell and CD19+ B‐cell subsets and higher levels of cytokines and chemokines including LT‐α, IL‐13, and CCL3. Significance This study, for the first time, showed that in temporal lobes of patients with TLE temperature and metabolite changes correlate with cellular and serum biomarkers of inflammation. Our results provide support for further development of MRSI‐t as a measure of neuroinflammation in epilepsy and potentially other neurological disorders and as an investigative and clinical tool. Plain Language Summary Neuroinflammation is associated with excessive heat production which can be visualized with magnetic resonance spectroscopic imaging and thermometry (MRSI‐t). We prospectively investigated the relationship between MRSI‐t and cellular and serum measures of peripheral inflammation in patients with temporal lobe epilepsy (TLE); we compared the results of MRSI‐t in patients with TLE to healthy controls. We showed a relationship between the temperature elevations in TLE and elevations of various measures of peripheral inflammation. Our results support further development of MRSI‐t as a measure of neuroinflammation in epilepsy and potentially other neurological disorders and as an investigative and clinical tool.

Thermal heating of biological samples allows to reversibly manipulate cellular processes with high temporal and spatial resolution. Manifold heating techniques in combination with live‐cell imaging were developed, commonly tailored to customized applications. They include Peltier elements and microfluidics for homogenous sample heating as well as infrared lasers and radiation absorption by nanostructures for spot heating. A prerequisite of all techniques is that the induced temperature changes are measured precisely which can be the main challenge considering subcellular structures or multicellular organisms as target regions. This article discusses heating and temperature sensing techniques for live‐cell imaging, leading to future applications in cell biology.

Interest in transcranial MR imaging-guided focused ultrasound procedures has recently grown. These incisionless procedures enable precise focal ablation of brain tissue using real-time monitoring by MR thermometry. This article will provide an updated review on clinically applicable technical underpinnings and considerations of proton resonance frequency MR thermometry, the most common clinically used MR thermometry sequence.

BACKGROUND: T2-weighted Single Shot Fast Spin Echo (SSFSE) scans at 3 Tesla (3T) are increasingly used to image fetal pathology due to their excellent tissue contrast resolution and signal-to-noise ratio (SNR). Temperature changes that may occur in response to radio frequency (RF) pulses used for these sequences at 3T have not been studied in human fetal brains. To evaluate the safety of T2-weighted SSFSE for fetal brains at 3T, magnetic resonance (MR) thermometry was used to measure relative temperature changes in a typical clinical fetal brain MR exam. METHODS: Relative temperature was estimated using sets of gradient recalled echo (GRE) images acquired before and after T2-weighted SSFSE images which lasted 27.47±8.19 minutes. Thirty-one fetuses with cardiac abnormalities, and 20 healthy controls were included in this study. Fetal brain temperature was estimated by proton resonance frequency (PRF) thermometry and compared to the estimated temperature in the gluteal muscle of the mother. Seven scans with excessive motion were excluded. Local outlier factor (LOF) was performed to remove 12 additional scans with spurious phase measurements due to motion degradation and potential field drift. Linear regression was performed to determine if temperature changes are dependent on the rate of energy deposition during the scan. RESULTS: For the 32 participants used in the analysis, 17 with cardiac abnormalities and 15 healthy controls, the average relative fetal temperate change was 0.19±0.73 ℃ higher than the mother, with no correlation between relative temperature change and the rate of images acquired during the scans (regression coefficient =-0.05, R-squared =0.05, P=0.22, F-statistic =1.60). The difference in the relative temperature changes between the fetal brain and mothers gluteal tissue in the healthy controls was on average 0.08 ℃ lower and found not to be statistically different (P=0.76) to the group with cardiac abnormalities. CONCLUSIONS: Our results indicate that the estimated relative temperature changes of the fetal brain compared to the mothers gluteal tissue from RF pulses during the course of the T2-weighted SSFSE fetal MR exam are minimal. The differences in acquired phase between these regions through the exam were found not to be statistically different. These findings support that fetal brain imaging at 3T is within FDA limits and safe.

As the demand for computing applications capable of processing large datasets increases, there is a growing need for new in-memory computing technologies. Oxide-based resistive random-access memory (RRAM) devices are promising candidates for such applications because of their industry readiness, endurance, and switching ratio. These analog devices, however, suffer from poor linearity and asymmetry in their analog resistance change. Various reports have found that the temperature in RRAM devices increases locally by more than 1000 K during operation. Therefore, temperature control is of paramount importance for controlling their resistance. In this study, scanning thermal microscopy is used to map the temperature of Au/Ti/HfOx/Au devices at a steady power state and to measure temperature dynamics of the top electrode above the filament location during both resistive switching loops and voltage pulsing. These measurements are used to verify the thermal parameters of a multiphysics finite elements model. The model is then used to understand the impact of thermal conductivities and boundary conductances of constituent materials on resistance change during the first reset pulse in RRAM devices. It is found that the resistance change can be reduced significantly when the temperature in the titanium capping layer is reduced. We find that the greatest temperature reduction and, therefore, the lowest resistance change in the device are afforded by capping layers with increased thermal conductivities. This work links thermal properties to the resistance change in RRAM devices, providing critical insights into engineering devices with improved switching dynamics. [ABSTRACT FROM AUTHOR]

Hyperthermia plays a significant role in cancer treatment by inducing cell damage through temperature elevation, often used alongside other treatment modalities. During hyperthermia therapy, temperature control is crucial. Here, we report on a simple synthesis route of hybrid plasmonic nanodiamonds either completely wrapped with an Au shell (NV@Au) or densely covered with Au NPs (NV@SiO 2 @Au). Such integration of nanodiamonds with Au NPs is advantageous both for heating and precise thermometry at nanoscale. After structural and optical investigations, heating abilities of the obtained plasmonic nanodiamonds were thoroughly inspected on glass, in association with living cells, and in tissue slices ex vivo, revealing their effective heat generation under excitation with light using a single excitation source. The developed hybrid plasmonic nanodiamonds were finally applied for local photothermal therapy of melanoma in vivo, demonstrating their efficacy in eradicating cancer cells and monitoring temperature during the process.

Excitation wavelength controllable lanthanide upconversion allows for real-time manipulation of luminescent color in a composition-fixed material, which has been proven to be conducive to a variety of applications, such as optical anti-counterfeiting and information security. However, current available materials highly rely on the elaborate core–shell structure in order to ensure efficient excitation-dependent energy transfer routes. Herein, multicolor upconversion luminescence in response to both near-infrared I and near-infrared II (NIR-I and NIR-II) excitations is realized in a novel but simple NaYGeO4:Yb3+/Er3+ phosphor. The remarkably enhanced red emission ratio under 1532 nm excitation, compared with that under 980 nm excitation, could be attributed to the Yb3+-mediated cross-relaxation energy transfers. Moreover, multi-wavelength excitable temperature-dependent (295–823 K) upconversion luminescence realizes a ratiometric thermometry relying on the thermally coupled levels (TCLs) of Er3+. Detailed investigations demonstrate that changing excitation wavelength makes little difference for the performances of TCL-based ratiometric thermometry of NaYGeO4:Yb3+/Er3+. These findings gain more insights to manipulate cross-relaxations for excitation controllable upconversion in single activator doped materials and benefit the cognition of the effect of excitation wavelength on ratiometric luminescence thermometry. [ABSTRACT FROM AUTHOR]

In this study, a solid-state reaction was employed to synthesize SrY 2 O 4 : Sm3+, SrY 2 O 4 : Eu3+ and SrY 2 O 4 : Sm3+/Eu3+ phosphors. An intriguing redshift phenomenon from charge transfer band (CTB) edge was investigated for single-band ratiometric (SBR) thermometry applications. The phosphors synthesized exhibited an orthogonal CaFe 2 O 4 structure with Pnam (62) space group. The Y3+ sites from host lattice were most likely to be replaced by Sm3+/Eu3+ ions. The sample of SrY 2 O 4 : 0.03 Sm3+/0.3Eu3+ showed a large degree of agglomeration with elongated particles, having an average size of approximately 4 μm. The energy bandgap decreased due to increased surface imperfections, resulting in enhanced defect level concentration. The dipole-dipole interaction could be used to explain energy transfer (ET) of Sm3+-Sm3+ and Sm3+-Eu3+. Furthermore, the energy transfer (ET) efficiency of Sm3+→Eu3+ in Sr 2 YO 4 reached 77.7 %. The sample exhibited a good thermal stability (90.956 %@423 K) with E a of 0.31 eV, which was an important parameter for broadening thermometry range. A thermometry strategy utilized this redshift phenomenon from CTB edge with anti-thermal quenching behavior and other peaks or bands with thermal quenching was therefore proposed. The high S r value of 1.533 % K−1@298 K provides a great potential for optical thermometry application, contributing significantly to the advancement of single band ratiometric thermometry technologies. [ABSTRACT FROM AUTHOR]

Fluorescence intensity ratio (FIR) thermometers have obtained great attention in industrial production, medical diagnosis and scientific research. However, the sensitivity has a large decline at high temperatures, which seriously limits the practical applications. Here, the Yb,Er,Tm:Sc 2 O 3 single crystal fibers were grown by laser-heated pedestal growth (LHPG) technique and its multi-mode FIR thermometry based on thermal coupled energy levels (TCLs) and non-thermal coupled energy levels (NTCLs) has been well demonstrated. The temperature measuring range of Yb,Er,Tm:Sc 2 O 3 single crystal fibers covers 298–973 K, with an increase of 2 orders of magnitude in absolute sensitivity. The relative sensitivity is higher than 0.02 % K−1 in the whole T-range of 298∼973 K, with a maximum value of 1.02 % K−1. Especially at the high temperatures of 973 K, it can still maintain 0.31 % K−1. This work proposes an innovative fluorescence intensity ratio detection strategy to achieve complementary disadvantages between TCLs and NTCLs and provides an effective method for improving detection sensitivity. [ABSTRACT FROM AUTHOR]

Accurate local temperature measurement at micro and nanoscales requires thermometry with high resolution because of ultra-low thermal transport. Among the various methods for measuring temperature, optical techniques have shown the most precise temperature detection, with resolutions reaching (~10−9 K). In this work, we present a nanomechanical device with nano-Kelvin resolution (~10−9 K) at room temperature and 1 atm. The device uses a 20 nm thick silicon nitride (SiN) membrane, forming an air chamber as the sensing area. The presented device has a temperature sensing area >1 mm2 for micro/nanoscale objects with reduced target placement constraints as the target can be placed anywhere on the >1 mm2 sensing area. The temperature resolution of the SiN membrane device is determined by deflection at the center of the membrane. The temperature resolution is inversely proportional to the membrane's stiffness, as detailed through analysis and measurements of stiffness and noise equivalent temperature (NET) in the pre-stressed SiN membrane. The achievable heat flow resolution of the membrane device is 100 pW, making it suitable for examining thermal transport on micro and nanoscales. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the dose-dependent brain temperature effects of transcranial photobiomodulation (t-PBM). Thirty adult subjects with major depressive disorder were randomized to three t-PBM sessions with different doses (low: 50 mW/cm2, medium: 300 mW/cm2, high: 850 mW/cm2) and a sham treatment. The low and medium doses were administered in continuous wave mode, while the high dose was administered in pulsed wave mode. A 3T MRI scanner was used to perform proton magnetic resonance spectroscopy (1H-MRS). A voxel with a volume of 30 × 30 × 15 mm3 was placed on the left prefrontal region. Brain temperature (°C) was derived by analyzing 1H-MRS spectrum chemical shift differences between the water (~ 4.7 ppm) and N-acetyl aspartate (NAA) (~ 2.01 ppm) peaks. After quality control of the data, the following group numbers were available for both pre- and post-temperature estimations: sham (n = 10), low (n = 11), medium (n = 10), and high (n = 8). We did not detect significant temperature differences for any t-PBM-active or sham groups post-irradiation (p-value range = 0.105 and 0.781). We also tested for potential differences in the pre-post variability of brain temperature in each group. As for t-PBM active groups, the lowest fluctuation (variance) was observed for the medium dose (σ2 = 0.29), followed by the low dose (σ2 = 0.47), and the highest fluctuation was for the high dose (σ2 = 0.67). t-PBM sham condition showed the overall lowest fluctuation (σ2 = 0.11). Our 1H-MRS thermometry results showed no significant brain temperature elevations during t-PBM administration. [ABSTRACT FROM AUTHOR]